NF-kappaB and AP-1 connection: mechanism of NF-kappaB-dependent regulation of AP-1 activity.

Nuclear factor kappaB (NF-kappaB) and activator protein 1 (AP-1) transcription factors regulate many important biological and pathological processes. Activation of NF-kappaB is regulated by the inducible phosphorylation of NF-kappaB inhibitor IkappaB by IkappaB kinase. In contrast, Fos, a key component of AP-1, is primarily transcriptionally regulated by serum responsive factors (SRFs) and ternary complex factors (TCFs). Despite these different regulatory mechanisms, there is an intriguing possibility that NF-kappaB and AP-1 may modulate each other, thus expanding the scope of these two rapidly inducible transcription factors. To determine whether NF-kappaB activity is involved in the regulation of fos expression in response to various stimuli, we analyzed activity of AP-1 and expression of fos, fosB, fra-1, fra-2, jun, junB, and junD, as well as AP-1 downstream target gene VEGF, using MDAPanc-28 and MDAPanc-28/IkappaBalphaM pancreatic tumor cells and wild-type, IKK1-/-, and IKK2-/- murine embryonic fibroblast cells. Our results show that elk-1, a member of TCFs, is one of the NF-kappaB downstream target genes. Inhibition of NF-kappaB activity greatly decreased expression of elk-1. Consequently, the reduced level of activated Elk-1 protein by extracellular signal-regulated kinase impeded constitutive, serum-, and superoxide-inducible c-fos expression. Thus, our study revealed a distinct and essential role of NF-kappaB in participating in the regulation of elk-1, c-fos, and VEGF expression.

Bioavailability of silver nanoparticles and ions: from a chemical and biochemical perspective

Owing to their antimicrobial properties, silver nanoparticles (NPs) are the most commonly used engineered nanomaterial for use in a wide array of consumer and medical applications. Many discussions are currently ongoing as to whether or not exposure of silver NPs to the ecosystem (i.e. plants and animals) may be conceived as harmful or not. Metallic silver, if released into the environment, can undergo chemical and biochemical conversion which strongly influence its availability towards any biological system. During this process, in the presence of moisture, silver can be oxidized resulting in the release of silver ions. To date, it is still debatable as to whether any biological impact of nanosized silver is relative to either its size, or to its ionic constitution. The aim of this review therefore is to provide a comprehensive, interdisciplinary overview--for biologists, chemists, toxicologists as well as physicists--regarding the production of silver NPs, its (as well as in their ionic form) chemical and biochemical behaviours towards/within a multitude of relative and realistic biological environments and also how such interactions may be correlated across a plethora of different biological organisms.

Transconvolution and the virtual positron emission tomograph--a new method for cross calibration in quantitative PET∕CT imaging

PURPOSE Positron emission tomography (PET)∕computed tomography (CT) measurements on small lesions are impaired by the partial volume effect, which is intrinsically tied to the point spread function of the actual imaging system, including the reconstruction algorithms. The variability resulting from different point spread functions hinders the assessment of quantitative measurements in clinical routine and especially degrades comparability within multicenter trials. To improve quantitative comparability there is a need for methods to match different PET∕CT systems through elimination of this systemic variability. Consequently, a new method was developed and tested that transforms the image of an object as produced by one tomograph to another image of the same object as it would have been seen by a different tomograph. The proposed new method, termed Transconvolution, compensates for differing imaging properties of different tomographs and particularly aims at quantitative comparability of PET∕CT in the context of multicenter trials. METHODS To solve the problem of image normalization, the theory of Transconvolution was mathematically established together with new methods to handle point spread functions of different PET∕CT systems. Knowing the point spread functions of two different imaging systems allows determining a Transconvolution function to convert one image into the other. This function is calculated by convolving one point spread function with the inverse of the other point spread function which, when adhering to certain boundary conditions such as the use of linear acquisition and image reconstruction methods, is a numerically accessible operation. For reliable measurement of such point spread functions characterizing different PET∕CT systems, a dedicated solid-state phantom incorporating (68)Ge∕(68)Ga filled spheres was developed. To iteratively determine and represent such point spread functions, exponential density functions in combination with a Gaussian distribution were introduced. Furthermore, simulation of a virtual PET system provided a standard imaging system with clearly defined properties to which the real PET systems were to be matched. A Hann window served as the modulation transfer function for the virtual PET. The Hann's apodization properties suppressed high spatial frequencies above a certain critical frequency, thereby fulfilling the above-mentioned boundary conditions. The determined point spread functions were subsequently used by the novel Transconvolution algorithm to match different PET∕CT systems onto the virtual PET system. Finally, the theoretically elaborated Transconvolution method was validated transforming phantom images acquired on two different PET systems to nearly identical data sets, as they would be imaged by the virtual PET system. RESULTS The proposed Transconvolution method matched different PET∕CT-systems for an improved and reproducible determination of a normalized activity concentration. The highest difference in measured activity concentration between the two different PET systems of 18.2% was found in spheres of 2 ml volume. Transconvolution reduced this difference down to 1.6%. In addition to reestablishing comparability the new method with its parameterization of point spread functions allowed a full characterization of imaging properties of the examined tomographs. CONCLUSIONS By matching different tomographs to a virtual standardized imaging system, Transconvolution opens a new comprehensive method for cross calibration in quantitative PET imaging. The use of a virtual PET system restores comparability between data sets from different PET systems by exerting a common, reproducible, and defined partial volume effect.

The association of genetic groups 1, 2, and 3 of Mycobacterium tuberculosis with pulmonary and extra-pulmonary tuberculosis

Objective. To investigate the association of the three major genetic groups of Mycobacterium tuberculosis with pulmonary and extra-pulmonary tuberculosis in clustered and non-clustered TB cases in the Houston area. ^ Study design. Secondary analysis of an ambi-directional study. ^ Study population. Three hundred fifty-eight confirmed cases of tuberculosis in the Houston that occurred between October 1995 and May 1997, who had been interviewed by the Houston T13 Initiative staff at Baylor College of Medicine, and whose isolates have had their DNA fingerprint and genetic group determined. ^ Exclusions. Individuals whose mycobacterial genotype was unknown, or whose data variables were unavailable. ^ Source of data. Laboratory results, patient interviews, and medical records at clinics and hospitals of the study population. ^ Results. In clustered cases, the majority of both, pulmonary and extra-pulmonary TB cases were caused by genetic group 1. Independent factors were assessed to determine the interactions that may influence the site of infection or increase the risk for one site or another. HIV negative males were protected against extra-pulmonary TB compared to HIV negative females. Individuals ages 1–14 years were at higher risk of having extra-pulmonary TB. Group 3 organisms were found less frequently in the total population in general, especially in extra-pulmonary disease. This supports the evidence in previous studies that this group is the least virulent and genetically distinct from the other two groups. Group 1 was found more frequently among African Americans than other ethnic groups, a trend for future investigations. ^ Among the non-clustered cases, group 2 organisms were the majority of the organisms found in both sites. They were also the majority of organisms found in African Americans, Caucasians, and Hispanics causing the majority of the infections at both sites. However, group 1 organisms were the overwhelming majority found in Asian/Pacific Islander individuals, which may indicate these organisms are either endemic to that area, or that there is an ethnic biological factor involved. This may also be due to a systematic bias, since isolates from individuals from that geographic region lack adequate copies of the insertion sequence IS6110, which leads to their placement in the non-clustered population. ^ The three genetic groups of Mycobacterium tuberculosis were not found equally distributed between sites of infection in both clustered and non-clustered cases. Furthermore, these groups were not distributed in the same patterns among the clustered and non-clustered cases, but rather in distinct patterns. ^

From Matterhorn to Mt Everest: empowering rescuers and improving medical care in Nepal.

This article describes a private initiative in which professional Swiss rescuers, based at the foot of the Matterhorn, trained Nepalese colleagues in advanced high altitude helicopter rescue and medical care techniques. What started as a limited program focused on mountain safety has rapidly developed into a comprehensive project to improve rescue and medical care in the Mt Everest area for both foreign travelers and the local Nepalese people.

Medical, psychological and socio-economic implications of chronic hand eczema: a cross-sectional study.

BACKGROUND Hand eczema (HE) is a common skin disease with major medical psychological and socio-economic implications. Onset and prognosis of HE are determined by individual as well as environmental factors. So far, most epidemiological data on HE have been reported from Scandinavian and recently German studies. OBJECTIVE To investigate the characteristics and medical care of patients with chronic HE (CHE) in Switzerland, and identify risk factors. METHODS In this cross-sectional study, data from patients with chronic HE were obtained by means of medical history, dermatological examination and patient questionnaires. Multiple logistic regression analysis was applied to identify risk factors for high severity and dermatology life quality index (DLQI). RESULTS In seven dermatology departments, 199 patients (mean age 40.4 years, 50.8% female) with CHE (mean duration 6.6 years) were enrolled. Moderate to severe HE was reported by 70.9% of patients, and was associated with age <30 or >50 years, localization of lesions and pruritus. Because of the CHE, 37.3% of patients were on sick leave over the past 12 months, 14.8% had changed or lost their job. Practically all patients applied topical therapy, 21% were treated with alitretinoin, and 21% with psoralen plus UVA light (PUVA). The effects on the health-related quality of life was moderate to large in 33.7% and 39.4% of CHE patients, respectively. Factors associated with a high impact on DLQI (mean 9.7 ± 5.8) were female sex, lesions on back of the hands and pruritus as well as mechanical skin irritation and wearing gloves. CONCLUSION In agreement with recent studies, the Swiss data demonstrate the high impact of CHE on medical well-being, patient quality of life and work ability. As it is associated with an intense use of health care services, high rate of sick leave, job loss and change, CHE may cause a high socio-economic burden.

Association of nutritional risk and adverse medical outcomes across different medical inpatient populations

OBJECTIVE The aim of this study was to examine the prevalence of nutritional risk and its association with multiple adverse clinical outcomes in a large cohort of acutely ill medical inpatients from a Swiss tertiary care hospital. METHODS We prospectively followed consecutive adult medical inpatients for 30 d. Multivariate regression models were used to investigate the association of the initial Nutritional Risk Score (NRS 2002) with mortality, impairment in activities of daily living (Barthel Index <95 points), hospital length of stay, hospital readmission rates, and quality of life (QoL; adapted from EQ5 D); all parameters were measured at 30 d. RESULTS Of 3186 patients (mean age 71 y, 44.7% women), 887 (27.8%) were at risk for malnutrition with an NRS ≥3 points. We found strong associations (odds ratio/hazard ratio [OR/HR], 95% confidence interval [CI]) between nutritional risk and mortality (OR/HR, 7.82; 95% CI, 6.04-10.12), impaired Barthel Index (OR/HR, 2.56; 95% CI, 2.12-3.09), time to hospital discharge (OR/HR, 0.48; 95% CI, 0.43-0.52), hospital readmission (OR/HR, 1.46; 95% CI, 1.08-1.97), and all five dimensions of QoL measures. Associations remained significant after adjustment for sociodemographic characteristics, comorbidities, and medical diagnoses. Results were robust in subgroup analysis with evidence of effect modification (P for interaction < 0.05) based on age and main diagnosis groups. CONCLUSION Nutritional risk is significant in acutely ill medical inpatients and is associated with increased medical resource use, adverse clinical outcomes, and impairments in functional ability and QoL. Randomized trials are needed to evaluate evidence-based preventive and treatment strategies focusing on nutritional factors to improve outcomes in these high-risk patients.

Environmental and behavioral risk factors for moderate or severe rotavirus diarrhea in children less than 24 months

On a global basis rotaviruses are the most important agents involved in childhood diarrhea. In developing countries they account for 6% of all diarrheas and 20% of all diarrhea related deaths of children under 5 years of age, with over 1 billion episodes and over 4 million deaths annually. Given the disease burden, there is a need for better understanding the risk factors involved in rotavirus disease, to identify areas of intervention. In order to provide this information, two areas were developed: a review of the literature, examining the causal evidence for rotavirus diarrhea and a case comparison study. The case comparison study analyzed two areas: identifying climate factors and, identifying environmental and behavioral risk factors. The literature review showed that few analytical studies have identified specific risk factors such as home environment, and a winter seasonal trend for temperate areas, but in key areas evidence is contradictory. The case comparison study for climate factors demonstrated that seasonality occurs in a tropical country like Venezuela and that a complex interplay between weather conditions contribute to the seasonal pattern. A positive association between rain fall (OR 4.1); dew point (OR 2.3) and temperature differential during the day (OR 1.4) and, an inverse association with temperature (OR 0.5) and relative humidity (OR 0.8) was found. This information is useful in understanding the seasonal pattern of rotavirus and for planning health care needs. The second analysis demonstrated that environmental variables such as crowding (OR 14.3), contact with someone with an infectious disease (OR 4.9) and animal ownership (OR 2.3) were important. Restricting the analysis to animal owners demonstrated that living In a rural settling (OR 13.8), defecating in inappropriate places (OR 7.2), crowding(4.2) and indoor animals (4.0) are of importance. Behavioral variables identified were: lack of breast feeding (OR 4.0) and visiting when someone was sick (OR 3.4). Biological and demographic variables of importance were: age, with a dose response relationship; undernurishment (OR 11.3) and household per capita monthly income less than US $ 16.30 (OR 8.5). Using a diarrhea compeer group we found that, although some of the previous variables were of importance, no major differences were found. These findings are important in identifying paths for prevention and further research. ^

The medical malpractice insurance "crises" and federal medical malpractice tort reform: Collection and analysis of bills passed by the United States House of Representatives from 1995--2005

There have been three medical malpractice insurance "crises" in the United States over a time spanning roughly the past three decades (Poisson, 2004, p. 759-760). Each crisis is characterized by a number of common features, including rapidly increasing medical malpractice insurance premiums, cancellation of existing insurance policies, and a decreased willingness of insurers to offer or renew medical malpractice insurance policies (Poisson, 2004, p. 759-760). Given the recurrent "crises," many sources argue that medical malpractice insurance coverage has become too expensive a commodity—one that many physicians simply cannot afford (U.S. Department of Health and Human Services [HHS], 2002, p. 1-2; Physician Insurers Association of America [PIAA], 2003, p. 1; Jackiw, 2004, p. 506; Glassman, 2004, p. 417; Padget, 2003, p. 216). ^ The prohibitively high cost of medical liability insurance is said to limit the geographical areas and medical specializations in which physicians are willing to practice. As a result, the high costs of medical liability insurance are ultimately said to affect whether or not people have access to health care services. ^ In an effort to control the medical liability insurance crises—and to preserve or restore peoples' access to health care—every state in the United States has passed "at least some laws designed to reduce medical malpractice premium rates" (GAO, 2003, p.5-6). More recently, however, the United States has witnessed a push to implement federal reform of the medical malpractice tort system. Accordingly, this project focuses on federal medical malpractice tort reform. This project was designed to investigate the following specific question: Do the federal medical malpractice tort reform bills which passed in the House of Representatives between 1995 and 2005 differ in respect to their principle features? To answer this question, the text of the bills, law review articles, and reports from government and private agencies were analyzed. Further, a matrix was compiled to concisely summarize the principle features of the proposed federal medical malpractice tort reform bills. Insight gleaned from this investigation and matrix compilation informs discussion about the potential ramifications of enacting federal medical malpractice tort reform legislation. ^

The role and mechanism of supressor of cytokine signaling 1 in brain metastasis

Brain metastasis, which occurs in 40%-60% of patients with advanced melanoma, has led directly to death in the majority of cases. Unfortunately, little is known about the biological and molecular basis of melanoma brain metastases. In our previous study, we developed a model to study human melanoma brain metastasis and found that Stat3 activity was increased in human brain metastatic melanoma cells when compared with that in cutaneous melanoma cells. The increased activation of Stat3 is also responsible for affecting melanoma angiogenesis in vivo and melanoma cell invasion in vitro and significantly affecting the expression of bFGF, VEGF, and MMP-2 in vivo and in vitro. Interestingly, a member of a new family of cytokine-inducible inhibitors of signal transduction, termed suppressors of cytokine signaling 1 (SOCS1) was found to negatively regulate the Janus kinase signal transducer and activator of transcription (Jak/STAT) signaling cascade. Here we report that restoration of SOCS1 expression by transfecting of SOCS1-expressing vector effectively inhibited melanoma brain metastasis through inhibiting Stat3 activation and further affecting melanoma angiogenesis and melanoma cell invasion in vitro, and significantly affected the expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinase-2 (MMP-2) in vitro and in vivo. In addition, we used cDNA array to compare mRNA expression in the SOCS1-transfected and vector-transfected cell lines and found some genes are tightly correlated to the restoration of SOCS1. One of them is Caveolin-1 (Cav-1). Cav-1 was reported to function as a tumor suppressor gene by several groups. Finally, the Cav-1 expression is up-regulated in SOCS1-overexpressing cell line. Further study found the regulation of Cav-1 by SOCS1 occurs through inhibiting Stat3 activation. Activated Stat3 binds directly to Cav-1 promoter and the Cav-1 promoter within -575bp is essential for active Stat3 binding. My studies reveal that Stat3 activation and SOCS1 expression play important roles in melanoma metastases. Moreover, the expression between SOCS1, Stat3 and Cav-1 forms a feedback regulation loop. ^

Disparities in medical expenditure and utilization among hypertensive men and women in the U.S.: Cross-section and lifetime analysis

Objectives. To investigate procedural gender equity by assessing predisposing, enabling and need predictors of gender differences in annual medical expenditures and utilization among hypertensive individuals in the U.S. Also, to estimate and compare lifetime medical expenditures among hypertensive men and women in the U.S. ^ Data source. 2001-2004 the Medical Expenditure Panel Survey (MEPS);1986-2000 National Health Interview Survey (NHIS) and National Health Interview Survey linked to mortality in the National Death Index through 2002 (2002 NHIS-NDI). ^ Study design. We estimated total medical expenditure using four equations regression model, specific medical expenditures using two equations regression model and utilization using negative binomial regression model. Procedural equity was assessed by applying the Aday et al. theoretical framework. Expenditures were estimated in 2004 dollars. We estimated hypertension-attributable medical expenditure and utilization among men and women. ^ To estimate lifetime expenditures from ages 20 to 85+, we estimated medical expenditures with cross-sectional data and survival with prospective data. The four equations regression model were used to estimate average annual medical expenditures defined as sum of inpatient stay, emergency room visits, outpatient visits, office based visits, and prescription drugs expenditures. Life tables were used to estimate the distribution of life time medical expenditures for hypertensive men and women at different age and factors such as disease incidence, medical technology and health care cost were assumed to be fixed. Both total and hypertension attributable expenditures among men and women were estimated. ^ Data collection. We used the 2001-2004 MEPS household component and medical condition files; the NHIS person and condition files from 1986-1996 and 1997-2000 sample adult files were used; and the 1986-2000 NHIS that were linked to mortality in the 2002 NHIS-NDI. ^ Principal findings. Hypertensive men had significantly less utilization for most measures after controlling predisposing, enabling and need factors than hypertensive women. Similarly, hypertensive men had less prescription drug (-9.3%), office based (-7.2%) and total medical (-4.5%) expenditures than hypertensive women. However, men had more hypertension-attributable medical expenditures and utilization than women. ^ Expected total lifetime expenditure for average life table individuals at age 20, was $188,300 for hypertensive men and $254,910 for hypertensive women. But the lifetime expenditure that could be attributed to hypertension was $88,033 for men and $40,960 for women. ^ Conclusion. Hypertensive women had more utilization and expenditure for most measures than hypertensive men, possibly indicating procedural inequity. However, relatively higher hypertension-attributable health care of men shows more utilization of resources to treat hypertension related diseases among men than women. Similar results were reported in lifetime analyses.^ Key words: gender, medical expenditures, utilization, hypertension-attributable, lifetime expenditure ^

Evaluation of the C5a anaphylatoxin and its receptor (CD88) in allergic lung disease

Allergic asthma is characterized by airflow obstruction, airway hyperresponsiveness (AHR) and chronic airway inflammation. We and others have reported that complement component C3 and the anaphylatoxin C3a receptor promote while C5 protects against the development of the biological and physiological hallmarks of allergic lung disease in mice. In this study, we assessed if the protective responses could be mediated by C5a, an activation-induced C5 cleavage product. Mice with ablation of the C5a receptor (C5aR) either by genetic deletion or by pharmacological blockade exhibited significantly exacerbated AHR compared to allergen-challenged wild-type (WT) mice. However, there were no significant differences in many of the other hallmarks of asthma such as airway infiltration by eosinophils or lymphocytes, pulmonary IL-4-producing cell numbers, goblet cell metaplasia, mucus secretion or total serum IgE levels. In contrast to elevated AHR, numbers of IL-5 and IL-13 producing pulmonary cells, and IL-5 and IL-13 protein levels, were significantly reduced in allergen-challenged C5aR-/- mice compared to allergen-challenged WT mice. Administration of a specific cysteinyl leukotriene receptor 1 (cysLT1R) antagonist before each allergen-challenge abolished AHR in C5aR-/- as well as in WT mice. Pretreatment with a C3aR antagonist dose-dependently reduced AHR in allergen-challenged WT and C5aR-/- mice. Additionally, allergen-induced upregulation of pulmonary C3aR expression was exaggerated in C5aR-/- mice compared to WT mice. In summary, deficiency or antagonism of C5aR in a mouse model of pulmonary allergy increased AHR, which was reversed or reduced by blockade of the cysLT1R and C3aR, respectively. In conclusion, this study suggests that C5a and C5aR mediate protection against AHR by suppressing cysLT and C3aR signaling pathways, which are known to promote AHR. This also supports important and opposing roles of complement components C3a/C3aR and C5a/C5aR in AHR. ^

Concomitant Mycobacterium tuberculosis infection and type 2 diabetes: A descriptive model with global health implications

The type 2 diabetes (diabetes) pandemic is recognized as a threat to tuberculosis (TB) control worldwide. This secondary data analysis project estimated the contribution of diabetes to TB in a binational community on the Texas-Mexico border where both diseases occur. Newly-diagnosed TB patients > 20 years of age were prospectively enrolled at Texas-Mexico border clinics between January 2006 and November 2008. Upon enrollment, information regarding social, demographic, and medical risks for TB was collected at interview, including self-reported diabetes. In addition, self-reported diabetes was supported by blood-confirmation according to guidelines published by the American Diabetes Association (ADA). For this project, data was compared to existing statistics for TB incidence and diabetes prevalence from the corresponding general populations of each study site to estimate the relative and attributable risks of diabetes to TB. In concordance with historical sociodemographic data provided for TB patients with self-reported diabetes, our TB patients with diabetes also lacked the risk factors traditionally associated with TB (alcohol abuse, drug abuse, history of incarceration, and HIV infection); instead, the majority of our TB patients with diabetes were characterized by overweight/obesity, chronic hyperglycemia, and older median age. In addition, diabetes prevalence among our TB patients was significantly higher than in the corresponding general populations. Findings of this study will help accurately characterize TB patients with diabetes, thus aiding in the timely recognition and diagnosis of TB in a population not traditionally viewed as at-risk. We provide epidemiological and biological evidence that diabetes continues to be an increasingly important risk factor for TB.^

Perinatal mortality and quality of care at the National Institute of Perinatology: A 3-year analysis

Quality of medical care has been indirectly assessed through the collection of negative outcomes. A preventable death is one that could have been avoided if optimum care had been offered. The general objective of the present project was to analyze the perinatal mortality at the National Institute of Perinatology (located in Mexico City) by social, biological and some available components of quality of care such as avoidability, provider responsibility, and structure and process deficiencies in the delivery of medical care. A Perinatal Mortality Committee data base was utilized. The study population consisted of all singleton perinatal deaths occurring between January 1, 1988 and June 30, 1991 (n = 522). A proportionate study was designed.^ The population studied mostly corresponded to married young adult mothers, who were residents of urban areas, with an educational level of junior high school or more, two to three pregnancies, and intermediate prenatal care. The mean gestational age at birth was 33.4 $\pm$ 3.9 completed weeks and the mean birthweight at birth was 1,791.9 $\pm$ 853.1 grams.^ Thirty-five percent of perinatal deaths were categorized as avoidable. Postnatal infection and premature rupture of membranes were the most frequent primary causes of avoidable perinatal death. The avoidable perinatal mortality rate was 8.7 per 1000 and significantly declined during the study period (p $<$.05). Preventable perinatal mortality aggregated data suggested that at least part of the mortality decline for amenable conditions was due to better medical care.^ Structure deficiencies were present in 35% of avoidable deaths and process deficiencies were present in 79%. Structure deficiencies remained constant over time. Process deficiencies consisted of diagnosis failures (45.8%) and treatment failures (87.3%), they also remained constant through the years. Party responsibility was as follows: Obstetric (35.4%), pediatric (41.4%), institutional (26.5%), and patient (6.6%). Obstetric responsibility significantly increased during the study period (p $<$.05). Pediatric responsibility declined only for newborns less than 1500 g (p $<$.05). Institutional responsibility remained constant.^ Process deficiencies increased the risk for an avoidable death eightfold (confidence interval 1.7-41.4, p $<$.01) and provider responsibility ninety-fivefold (confidence interval 14.8-612.1, p $<$.001), after adjustment for several confounding variables. Perinatal mortality due to prematurity, barotrauma and nosocomial infection, was highly preventable, but not that due to transpartum asphyxia. Once specific deficiencies in the quality of care have been identified, quality assurance actions should begin. ^