In vitro analog of classical conditioning of feeding behavior in aplysia.

The feeding behavior of Aplysia californica can be classically conditioned using tactile stimulation of the lips as a conditioned stimulus (CS) and food as an unconditioned stimulus (US). Moreover, several neural correlates of classical conditioning have been identified. The present study extended previous work by developing an in vitro analog of classical conditioning and by investigating pairing-specific changes in neuronal and synaptic properties. The preparation consisted of the isolated cerebral and buccal ganglia. Electrical stimulation of a lip nerve (AT4) and a branch of the esophageal nerve (En2) served as the CS and US, respectively. Three protocols were used: paired, unpaired, and US alone. Only the paired protocol produced a significant increase in CS-evoked fictive feeding. At the cellular level, classical conditioning enhanced the magnitude of the CS-evoked synaptic input to pattern-initiating neuron B31/32. In addition, paired training enhanced both the magnitude of the CS-evoked synaptic input and the CS-evoked spike activity in command-like neuron CBI-2. The in vitro analog of classical conditioning reproduced all of the cellular changes that previously were identified following behavioral conditioning and has led to the identification of several new learning-related neural changes. In addition, the pairing-specific enhancement of the CS response in CBI-2 indicates that some aspects of associative plasticity may occur at the level of the cerebral sensory neurons.

The development and characterization of two types of chronic responses in irradiated mouse colon

The hypothesis to be tested is that there are two distinct types of chronic responses in irradiated normal tissues, each resulting from damage to different cell populations in the tissue. The first is a sequala of chronic epithelial depletion in which the tissue's integrity cannot be maintained, i.e. a "consequential" chronic response. The other response is due to cell loss in the connective tissue and/or vascular stroma, i.e. a "primary" chronic response. The purpose of this study was to test the hypothesis in the murine colon by first, establishing a model of each chronic response and then, by determining whether the responses differed in timing of expression, histology, and expression of specific collagen types. The model of late damage used was colonic obstructions/strictures induced by a single dose of 27 Gy ("consequential" response) and two equal doses of 14.75 Gy (t = 10 days) ("primary" response). "Consequential" lesions appeared as early as 5 weeks after 27 Gy and were characterized by a deep mucosal ulceration and a thickened fibrotic serosa containing excessive accumulations of collagen types I and III. Both types were commingled in the scar at the base of the ulcer. Fibroblasts were synthesizing pro-collagen types I and III mRNA 10 weeks prior to measurable increases in collagen. A significant decrease in the ratio of collagen types I:III was associated with the "consequential" response at 4-5 months post-irradiation. The "primary" response, on the other hand, did not appear until 40 weeks after the split dose even though the total dose delivered was approximately the same as that for the "consequential" response. The "primary" response was characterized with an intact mucosa and a thickened fibrotic submucosa which contained excessive amounts of only collagen type I. An increased number of fibroblasts were synthesizing pro-collagen type I mRNA nearly 25 weeks before collagen type I levels were increased. The "primary" response lesion had a significantly elevated collagen type I:III ratio at 10-13 months post-irradiation. These data show a clear difference between the two chronic response and suggest that not all chronic responses share a common pathogenesis, but depend on the cell population in the tissue that is damaged. ^

IN VITRO INDUCTION OF XENOIMMUNE RESPONSES TO LIPOSOMES CONTAINING HUMAN COLON TUMOR ANTIGENS

Liposomes prepared with human LS174T colon tumor cell membranes induce specific primary and secondary xenogeneic immune responses in BALB/c splenocytes in vitro. The multilamellar vesicular liposomes were prepared by adding sonicated membrane fragments in 8 mM CaCl(,2) to a dried lipid film. Cytoxic splenocytes generated in vivo exhibited specificity for the LS174T cell; liposomes elicited higher levels of cytotoxicity than did membranes (P < 0.01). Secondary blastogenic responses elicited in in vivo-primed spleen cells by liposomes also produced a significantly greater (P < 0.005) response than membranes. Subsequently, in vitro induction of primary blastogenic and cytotoxic responses by liposomes were accomplished and revealed similar kinetics to that of whole LS174T cell immunogens. Specificity of the in vitro-primed spleen cells was clearly demonstrated (P < 0.01) on a variety of human tumor cells using both the primed lymphocyte and cell-mediated cytotoxicity assays. The results of competitive inhibition tests with autologous lymphoblasts demonstrated that 30% of the cytotoxic activity was directed against lymphocyte antigens.^ The adjuvant effect of liposomes was shown to be mediated primarily by tumor antigens exposed on the outer surface of liposomes. Trypsinization of the liposomes which eliminated 96% of the surface protein reduced the ability of liposomes to induce cytotoxic splenocytes. The generation of cytolytic activity with liposomes of increasing protein concentration showed that while 10 (mu)g protein was threshold, 100 (mu)g protein induced maximal responses. In addition, membrane fluidity studies revealed that rigid liposomes were significantly (P < 0.05) more efficacious than fluid liposomes in inducing cytotoxicity.^ The induction of the primary response required the presence of nonadherent splenocytes bearing the Thy-1, Lyt-1, and Lyt-2 surface markers. The role of a Lyt-123 subpopulation was suggested by the inability of both the Lyt-1 and Lyt-2 depleted populations to completely restore the cytolytic levels to normal. In addition, the interaction of I-A('+) spleen adherent cells with liposomes for at least 8 hours was required to generate maximal cytotoxic activity. The phenotype of the cytotoxic effector was Thy-1('+), Lyt-2('+), and I-A('d-).^ Incorporation of tumor antigens into liposomes has thus enabled primary immunization in vitro to human colon cancer antigens and may afford an adaptable means to evaluate and to select specific immune responses, as well as to identify colon tumor-specific determinants.^

Behavioral and cellular analysis of classical conditioning of feeding behavior in Aplysia

In classical conditioning, an associative form of learning, animals learn to associate two stimuli. Cellular and molecular mechanisms for the induction and consolidation of associative learning and memory at the level of single cells and synaptic connections have been studied in both vertebrate and invertebrate animals. The majority of studies, however, relied on aversive stimuli to induce learning. This bias may limit the extent to which identified mechanisms generalize to other forms of associative learning and memory, such as appetitive forms. The goal of the present study was to develop a classical conditioning procedure for the marine mollusk Aplysia californica using appetitive reinforcement, and to analyze associative learning using behavioral and electrophysiological techniques. ^ Using tactile stimulation of the lips as the conditional stimulus (CS) and food as the unconditional stimulus (US) a training protocol was developed that reliably induced classical conditioning of feeding behavior. Memory persisted for at least 24 hours. The gross organization of reinforcement-mediating pathways was analyzed in additional behavioral experiments. Moreover, neurophysiological correlates of classical conditioning were identified and characterized in an in vitro preparation containing the circuitry for feeding behavior. In vitro stimulation of a nerve (AT4) that may mediate the CS during training, resulted in a greater number of buccal motor patterns (BMPs) in brains from conditioned animals, as compared to control animals. The majority of these BMPs were ingestion-like, consistent with the increased number of bites in response to the CS after classical conditioning. Moreover, classical conditioning correlated with increased excitatory synaptic input to BMP-initiating neuron B31/32, in response to stimulation of AT 4, as compared to controls. The expression of the correlates of classical conditioning identified in this study was specific to stimulation of AT 4, which is consistent the stimulus specificity that is characteristic for classical conditioning. ^ The identification of cellular correlates of classical conditioning documented here provides the basis for future, more detailed analyses of an appetitive form of associative learning and memory, that may extend the working knowledge of the cellular and molecular mechanisms for associative plasticity in general. ^

Mechanisms involved in suppression of the elicitation of immune responses by ultraviolet light

The ultraviolet radiation (UVR) present in sunlight is the primary cause of nonmelanoma skin cancer and has been implicated in the development of cutaneous malignant melanoma. Ultraviolet radiation also suppresses the immune response. In the majority of studies investigating the mechanisms regulating UV-induced immune suppression, UV is used to suppress the induction of immune responses. Equally important, is the ability of UVR to suppress established immune responses, such as the recall reaction in humans, which protects against microbial infections. We established a murine model to help elucidate the immunological mechanisms governing UV-induced suppression of the elicitation of immune responses. 80 kJ/m2 of UVR nine days after sensitization consistently suppressed the elicitation of delayed type hypersensitivity reaction to C. albicans . We found ultraviolet A (320±400 nm) radiation was as effective as solar-simulated ultraviolet A + B (290±400 nm) in suppressing the elicitation of an established immune response. The mechanisms involved in UV-induced suppression of the induction & elicitation of the immune response are similar. For example, mice irradiated with UV after immunization generated antigen-specific T suppressor cells. Injection of monoclonal antibodies to IL-10 or recombinant IL-12 immediately after exposure to UVR blocked immune suppression. Liposomes containing bacteriophage T4N5 to the skin of mice also prevented immune suppression, demonstrating an essential role for ultraviolet-induced DNA damage in the suppression of established immune reactions. ^ In addition to damaging DNA, UV initiates immune suppression through the isomerization of urocanic acid in the epidermis. Here we provide evidence that cis-UCA induces systemic immunosuppression via the serotonin (5-hydroxyyryptamine; 5-HT) receptor. Biochemical and immunological analysis indicate that cis-UCA binds to, and activates, the serotonin receptor. Moreover, serotonin specific antibodies block UV- and/or cis-UCA-induced immune suppression. Our findings identify cis-UCA as novel serotonin receptor ligand and indicate that serotonin receptor engagement can activate immune suppression. Cumulatively, our data suggest that similar immune regulatory mechanisms are activated regardless of whether we expose mice to solar-simulated UV (UVA + UVB) radiation or UVA only, and that ultraviolet radiation activates similar immunologic pathways to suppress the induction or the elicitation of the immune response. ^

Investigations of stress responses in Saccharomyces cerevisiae: Transcriptional control and heat shock protein function

The baker's yeast, Saccharomyces cerevisiae responds to the cytotoxic effects of elevated temperature (37-42°C) by activating transcription of ∼150 genes, termed heat shock genes, collectively required to compensate for the abundance of misfolded and aggregated proteins and various physiological modifications necessary for the cell to survive and grow at heat shock temperatures. An intriguing facet of the yeast heat shock response is the remarkable similarity it shares with the global remodeling that occurs in mammalian cells in response to numerous pathophysiological conditions including cancer and cardiovascular disease and thus provides an ideal model system. I have therefore investigated several novel features of stress signaling, transcriptional regulation, and physiology. Initial work focused on the characterization of SYM1, a novel heat shock gene in yeast which was demonstrated to be required for growth on the nonfermentable carbon source ethanol at elevated temperature, and to be the functional ortholog of the mammalian kidney disease gene, Mpv17. Additional work addressed the role of two proteins, the Akt-related kinase, Sch9, and Sse1, the yeast Hsp110 protein chaperone homolog, in signaling by protein kinase A, establishing Sse1 as a critical negative regulator of this pathway. Furthermore, I have demonstrated a role for Sse1 in biogenesis and stability of the stress-response transcription factor, Msn2; a finding that has been extended to include a select subset of additional high molecular weight proteins, suggesting a more global role for this chaperone in stabilizing the cellular proteome. The final emphasis of my doctoral work has included the finding that celastrol, a compound isolated from the plant family Celasfraceae, a component of traditional Chinese herbal medicine, can activate heat shock transcription factor (Hsf1) in yeast and mammalian cells through an oxidative stress mechanism. Celastrol treatment simultaneously activates both heat shock and oxidative stress response pathways, resulting in increased cytoprotection. ^

The impact of traditional psychiatric services and case management services on the functioning of people with schizophrenia: A cross-national study in Nova Scotia and Texas

The purpose of this study was to determine the impact of traditional psychiatric services with case management services on the functioning of people with schizophrenia. Traditional services were defined as routine clinic services consisting of medication follow-along, psychotherapy, and support services. Case management consisted of activities involved in linking, planning, and monitoring services for the outpatient client who has schizophrenia. The target population was adult schizophrenics who had been receiving outpatient clinic services for a minimum of six months. Structured interviews were conducted using standardized scales (e.g., Quality of Life, Self-Efficacy, and Brief Symptom Inventory) with 78 outpatient client volunteers from two sites: Nova Scotia (Canada) and Texas (USA). The researcher tested for differences in psychiatric symptomatology, recidivism, and quality of life for persons with schizophrenia receiving traditional psychiatric services in Nova Scotia and traditional plus case management services in Texas. Data were collected from the structured interviews and medical records review forms. Types of services were blocked into low and high levels of Intensity (frequency x minutes) and compared to determine the relative contribution of each. Finally, the role of clients' self-efficacy was tested as an intervening variable. Although the findings did not support the hypotheses in the direction anticipated, there were some interesting and useful results. From the Nova Scotia site, clients who received low levels of services were hospitalized less compared to the Texas site. The more psychotic a patient was the higher their involvement in medication follow-along and the more monitoring they received. The more psychotherapy received, the lower the reported satisfaction with social relationships. Of particular interest is the role that self-efficacy played in improved client outcomes. Although self-efficacy scores were related to improved functioning, the mechanism for this still needs to be clarified through subsequent research. ^

"I understood what she meant when she said '21st century medicine'": A qualitative analysis of patient responses for plans for colorectal cancer screening following a recommendation from their physician

Although physician recommendation has been significantly associated with colorectal cancer screening (CRCS), it still does not motivate all patients to get CRCS. Although improved physician recommendation for CRCS has been shown to increase patient CRCS screening, questions remain about what elements of that discussion may lead to screening. The objective of this study is to describe patients' perceptions and interpretations about their physician's recommendation for CRCS during their annual wellness exam. A subset of patients (n=51) participating in a supplement study of a behavioral intervention trial designed to increase CRCS completed a follow-up, open-ended interview two to four weeks after their annual wellness visit. Using qualitative methods, transcripts of these interviews were analyzed. Findings suggest that most patients would follow their physician's recommendation for CRCS despite not engaging in much discussion. Patients may refrain from CRCS discussion because of a commitment to CRCS, awareness of screening guidelines, and trust in physician's honesty and beneficence. Yet many patients left their wellness exams with questions, refraining because of future plans to consult with their physicians, perceived time constraints or a lack of a patient-physician relationship. If patients are leaving their wellness exams with unanswered questions, interventions should prepare physicians for patient reticence, teaching physicians how to assure patients that CRCS is a primary care activity where all questions and concerns, including cost and scheduling, may be resolved.^

The role of suppressor factors in the regulation of immune responses by ultraviolet radiation -induced suppressor T lymphocytes

The purpose of these studies was to determine the role of suppressor factors (TsF) in the regulation of immune responses by ultraviolet radiation-induced suppressor T lymphocytes (Ts). The Ts were induced following epicutaneous sensitization with contact allergens to an unirradiated site on mice irradiated five days earlier with 40 kJ/m$\sp2$ UVB (280-320 nm) radiation. The spleens of such mice contain afferent, hapten-specific, Thy-1$\sp+$, Lyt-1$\sp+$,2$\sp-$ Ts that suppress in vivo contact hypersensitivity (CHS) and antibody responses and the in vitro generation of cytotoxic T lymphocytes (CTL). Four approaches were used to determine the role of TsF. First, lysates produced from sonically-disrupted Ts were injected i.v. into normal animals; they inhibited CHS in vivo in a nonspecific manner. The lysates suppressed the induction and elicitation of CHS, and they inhibited the in vitro generation of CTL. Lysates prepared from splenocytes obtained from unirradiated mice or UV-irradiated, unsensitized mice failed to inhibit either response. Second, supernatants from cultures containing Ts, normal syngeneic responder lymphocytes, and hapten-modified stimulator cells were injected i.v. into normal recipients. They inhibited the induction of CHS and did so in a hapten-specific manner. Cellular and kinetic requirements were observed for the generation of suppressive activity. Splenocytes from mice treated with Ts supernatants suppressed CHS when transferred into normal animals. The supernatants also suppressed the in vitro generation of specific CTL. Third, the TsF-specific B16G monoclonal antibody was tested for its ability to modulate the effects of UV radiation in vivo. The i.v. injection of B16G into UV-irradiated mice reduced the suppression of CHS. Splenocytes of B16G-treated mice transferred into normal recipients, and they suppressed CHS, indicating that the Ts were not depleted. Fourth, B16G was used to isolate a putative TsF by antibody immunoadsorbance. When the B16G-bound fraction was eluted and injected i.v. into normal animals, it suppressed CHS and represented a 900-fold enrichment of activity over the starting material, based on specific activity. By SDS-PAGE, the B16G-bound material contained nondisulfide-linked 45- and 50-kDa components. These results suggest that TsF may play an immunoregulatory role in CHS. The isolation of a UV radiation-induced TsF lends credence to the involvement of such molecules. ^

Learning in the cerebellar nucleus is necessary for acquisition of Pavlovian eyelid conditioning

The cumulative work presented here supports the hypothesis that plasticity in the cerebellar cortex and cerebellar nuclei mediates a simple associative form of motor teaming-Pavlovian eyelid conditioning. It was previously demonstrated that focal ablative lesions of cerebellar anterior lobe or pharmacological block of the cerebellar cortex output disrupted the timing of the conditioned eyeblink response, unmasking a response with a relatively fixed and very short latency to onset. The results of this thesis demonstrate that the short-latency responses are due to associative learning. Unpaired training does not support the acquisition of short-latency responses while the rate of acquisition of short-latency responses during paired training is approximately the same as that of timed conditioned responses. The acquisition of short-latency responses is dependent on an intact cerebellar cortex. Both ablative lesions of the cerebellar cortex and inactivation of cerebellar cortex output with picrotoxin block the acquisition of short-latency responses. However, once the short-latency responses are acquired neither disconnection of cerebellar cortex nor inactivation of the cerebellar nucleus block reacquisition. The results are consistent with the proposal that plasticity in the cerebellar cortex is necessary for learning the timing of conditioned responses, plasticity in the interpositus nucleus mediates the short latency responses, and cerebellar cortical output and mossy fiber input are necessary for the acquisition of short latency responses. ^

Polysensory interneuronal projections to foot contractile pedal neurons in Hermissenda.

A Pavlovian-conditioning procedure may produce modifications in multiple behavioral responses. As an example, conditioning may result in the elicitation of a specific somatomotor conditioned response (CR) and, in addition, other motor and visceral CRs. In the mollusk Hermissenda conditioning produces two conditioned responses: foot-shortening and decreased locomotion. The neural circuitry supporting ciliary locomotion is well characterized, although the neural circuit underlying foot-shortening is poorly understood. Here we describe efferent neurons in the pedal ganglion that produce contraction or extension of specific regions of the foot in semi-intact preparations. Synaptic connections between polysensory type Ib and type Is interneurons and identified foot contractile efferent neurons were examined. Type Ib and type Is interneurons receive synaptic input from the visual, graviceptive, and somatosensory systems. Depolarization of type Ib interneurons evoked spikes in identified tail and lateral foot contractile efferent neurons. Mechanical displacement of the statocyst evoked complex excitatory postsynaptic potentials (EPSPs) and spikes recorded from type Ib and type Is interneurons and complex EPSPs and spikes in identified foot contractile efferent neurons. Depolarization of type Ib interneurons in semi-intact preparations produced contraction and shortening along the rostrocaudal axis of the foot. Depolarization of Is interneurons in semi-intact preparations produced contraction of the anterior region of the foot. Taken collectively, the results suggest that type Ib and type Is polysensory interneurons may contribute to the neural circuit underlying the foot-shortening CR in Hermissenda.

5-HT and GABA modulate intrinsic excitability of type I interneurons in Hermissenda.

The sensory neurons (photoreceptors) in the visual system of Hermissenda are one site of plasticity produced by Pavlovian conditioning. A second site of plasticity produced by conditioning is the type I interneurons in the cerebropleural ganglia. Both photoreceptors and statocyst hair cells of the graviceptive system form monosynaptic connections with identified type I interneurons. Two proposed neurotransmitters in the graviceptive system, serotonin (5-HT) and gamma-aminobutyric acid (GABA), have been shown to modify synaptic strength and intrinsic neuronal excitability in identified photoreceptors. However, the potential role of 5-HT and GABA in plasticity of type I interneurons has not been investigated. Here we show that 5-HT increased the peak amplitude of light-evoked complex excitatory postsynaptic potentials (EPSPs), enhanced intrinsic excitability, and increased spike activity of identified type I(e(A)) interneurons. In contrast, 5-HT decreased spike activity and intrinsic excitability of type I(e(B)) interneurons. The classification of two categories of type I(e) interneurons was also supported by the observation that 5-HT produced opposite effects on whole cell steady-state outward currents in type I(e) interneurons. Serotonin produced a reduction in the amplitude of light-evoked complex inhibitory PSPs (IPSPs), increased spontaneous spike activity, decreased intrinsic excitability, and depolarized the resting membrane potential of identified type I(i) interneurons. In contrast to the effects of 5-HT, GABA produced inhibition in both types of I(e) interneurons and type I(i) interneurons. These results show that 5-HT and GABA can modulate the intrinsic excitability of type I interneurons independent of the presynaptic effects of the same transmitters on excitability and synaptic efficacy of photoreceptors.

IMMUNE MODULATION OF THE MYCOBACTERIUM TUBERCULOSIS GRANULOMATOUS RESPONSE

Tuberculosis (TB) remains a major public health burden. The immunocompetant host responds to Mycobacterium tuberculosis (MTB) infection by the formation of granulomas, which initially prevent uncontrolled bacterial proliferation and dissemination. However, increasing evidence suggests that granuloma formation promotes persistence of the organism by physically separating infected cells from effector lymphocytes and by inducing a state of non-replicating persistence in the bacilli, making them resistant to the action of antibiotics. Additionally, immune-mediated tissue destruction likely facilitates disease transmission. The granulomatous response is in part due to mycobacterial glycolipid antigens. Therefore, studies were first undertaken to determine the innate mechanisms of mycobacterial cord factor trehalose-6’6-dimycolate (TDM) on granuloma formation. Investigations using knock-out mice suggest that TNF-a is involved in the initiation of the granulomatous response, complement factor C5a generates granuloma cohesiveness, and IL-6 is necessary for maintenance of an established granulomatous responses. Studies were next performed to determine the ability of lactoferrin to modulate the immune response and pathology to mycobacterial cord factor. Lactoferrin is an iron-binding glycoprotein with immunomodulatory properties that decrease tissue damage and promote Th1 responses. Mice challenged with TDM and treated with lactoferrin had decreased size and numbers of granulomas at the peak of the granulomatous response, accompanied by increased IL-10 and TGF-b production. Finally, the ability of lactoferrin to serve as a novel therapeutic for the treatment of TB was performed by aerosol challenging mice with MTB and treating them with lactoferrin added to the drinking water. Mice given tap water had lung log10 CFUs of 7.5 ± 0.3 at week 3 post-infection. Lung CFUs were significantly decreased in mice given lactoferrin starting the day of infection (6.4 ± 0.7) and mice started therapeutically on lactoferrin at day 7 after established infection (6.5 ± 0.4). Total lung inflammation in lactoferrin treated mice was significantly decreased, with fewer areas of macrophages, increased total lymphocytes, and increased numbers of CD4+ and CD8+ cells. The lungs of lactoferrin treated mice had increased CD4+ IFN-g+ cells and IL-17 producing cells on ELISpot analysis. It is hypothesized that lactoferrin decreases bacterial burden during MTB infection by early induction of Th1 responses.

Content of prenatal care and spontaneous preterm birth: Findings from the 1988 National Maternal and Infant Health Survey

The purposes of this study were to examine (1) the relationship between selected components of the content of prenatal care and spontaneous preterm birth; and (2) the degree of comparability between maternal and caregivers' responses regarding the number of prenatal care visits, selected components of the content of prenatal care, and gestational age, based on analyses of the 1988 National Maternal and Infant Health Survey conducted by the National Centers for Health Statistics. Spontaneous preterm birth was subcategorized into very preterm and moderately preterm births, with term birth as the controls. The study population was limited to non-Hispanic Anglo- and African-American mothers. The racial differences in terms of birth outcomes were also compared.^ This study concluded that: (1) there was not a high degree of comparability (less than 80%) between maternal and prenatal care provider's responses regarding the number of prenatal care visits and the content of prenatal care; (2) there was a low degree of comparability (less than 50%) between maternal and infant's hospital of delivery responses regarding gestational age at birth; (3) there were differences in selected components of the content of prenatal care between the cases and controls, overall and stratified by ethnicity (i.e., hemoglobin/hematocrit test, weight measurement, and breast-feeding counseling), but they were confounded with missing values and associated preterm delivery bias; (4) there were differences in selected components of the content of prenatal care between Anglo- and African-American cases (i.e., vitamin/mineral supplement advice, weight measurement, smoking cessation and drug abuse counseling), but they, too, were difficult to interpret definitively due to item nonresponse and preterm delivery biases; (5) no significant predictive association between selected components of the content of prenatal care and spontaneous preterm birth was found; and (6) inadequate/intermediate prenatal care and birth out of wedlock were found to be associated with moderately preterm birth.^ Future research is needed to examine the validity of maternal and prenatal care providers' responses and identify the sources of disagreement between their responses. In addition, further studies are needed to examine the relationship between the quality of prenatal care and preterm birth. Finally, the completeness and quality of patient and provider data on the utilization and content of prenatal care needs to be strengthened in subsequent studies. ^

A study of the impact of cigarette advertising on adolescent susceptibility to smoking among 5th-, 8th-, and 12th-grade students in Hempstead and Hitchcock Independent School Districts

This study assessed the impact of cigarette advertising on adolescent susceptibility to smoking in the Hempstead and Hitchcock Independent School Districts. A convenience sample of 217 youths, 10-19 years of age was recruited in the study. Students completed both a paper-and-pencil and a computer-aided questionnaire in April 1996. Adolescents were defined as susceptible to smoking if they could not definitely rule out the possibility of future smoking. For the analysis, an index was devised: a 5-point index of an individual's receptivity to cigarette advertising. The index is determined by the number of positive responses to five survey items (recognizing cigarette brand logos, recognizing cigarette advertisement's pictures, recognizing cigarette brand slogans, evaluating adolescent attitudes toward cigarette advertising, and the degree to which adolescents were exposed to cigarette advertisements). Using logistic regression, we assessed the independent importance of the index in predicting susceptibility to smoking and ever smoking after adjusting for sociodemographic variables, perceived school performance and family composition. Of students surveyed, 54.4% of students appeared to have started the smoking uptake process as measured by susceptibility to smoking. Camel was recognized by the majority of students (88%), followed by Marlboro (41.5%) and Newport (40.1%). The pattern for recognition of the cigarette advertisements was the same as the pattern of market for cigarette. Advertisement featuring the cartoon character Joe Camel was significantly more appealing to adolescents than were advertisements with human models, with animal models, and with text only (p $<$ 0.001). Text only advertisement was significantly less appealing than other types of advertisements. The cigarette advertisement with White models (Marlboro) had significantly higher appeal to White students than to African-American students (p $<$ 0.001). The cigarette advertisement featuring African-American models (Virginia Slims) was significantly more appealing to African-American students than other ethnic groups (p $<$ 0.001). Receptivity to cigarette advertising was to be an important concurrent predictor of past smoking experience and intention to smoke in the future. Adolescents who scored in the fourth quartile of the Index of Receptivity to Cigarette Advertising were 7.54 (95% confidence interval (CI) = 1.92-29.56) times as likely to be susceptible to smoking, and were 4.56 (95% CI = 1.55-13.38) times as likely to have tried smoking, as those who scored in the first quartile of the Index. The findings confirmed the hypothesis that cigarette advertising may be a strong current influence in encouraging adolescents to initiate the smoking uptake process than sociodemographic variables, perceived school performance and family composition. ^