CIRCADIAN RHYTHM IN THE BIOAVAILABILITY OF ORALLY ADMINISTERED THEOPHYLLINE

The effect of time (i.e., biologic time structure) of drug administration on the bioavailability of theophylline was investigated in man after both a single dosage as well as after repeated, or chronic, drug administrations. Preliminary laboratory investigations on Balb-C mice showed the toxic

Aggression, impulsivity and serotonin in drug dependence

Aggression, impulsivity, and central serotonergic function were evaluated in two groups of human volunteers; one group having a history of substance dependence (DRUG+) and another group with no drug use history (DRUG$-$). The hypothesis was that DRUG+ subjects would be more aggressive, more impulsive, and have attenuated serotonergic function. Results showed that DRUG+ subjects behaved more aggressively in a computer paradigm of aggression and also reported more aggression on questionnaires than DRUG$-$ subjects. In a computer paradigm of impulsivity, the DRUG+ group showed a lesser ability to delay gratification than the DRUG$-$ group in the last session of testing. The DRUG+ subjects also reported more venturesomeness and problems associated with low impulse control on questionnaires. Serotonergic function was measured through the neuroendocrine and hypothermic response to an orally administered serotonin (5-HT) agonist specific to the 5-HT$\rm\sb{1A}$ receptor subtype (ipsapirone). The neuroendocrine responses did not differ between DRUG$\pm$ groups, indicating no difference in the sensitivity of the presynaptic or postsynaptic 5-HT$\rm\sb{1A}$ receptors. An unexpected result was that the indicator hormone, cortisol, was at a lower baseline level in the DRUG+ group than the DRUG$-$ group. Lowered cortisol levels have been previously noted in children at high risk foul antisociality and future drug use. A principal components analysis including impulsivity, aggression, and serotonergic function measures produced three unique factors. The factors, Antisocial Tendency and Self-Control and Serotonergic Function combined to produce a significant regression equation explaining 36% of variability in the DRUG$\pm$ groups. These factors included measures of aggression, impulsivity, mood, and educational attainment. These results suggest that the current measures of aggression and impulsivity were predictive of a drug dependence disorder but that neuroendocrine function is not yet a useful indicator of drug dependence status. ^

Using Blackboard Administered Precourse and Post course Tests to Assess Student Readiness to Learn and Change in Knowledge

Students arrive at classes with a varying social situations and course subject knowledge. Blackboard is a web based course delivery program that permits testing of students before arriving at the first class. A pretest was used to assess preexisting subject knowledge(S) and a survey was used to assess non-subject (N) factors that might impact the student’s final grade. A posttest was administered after all content was delivered and used to access change in S. [See PDF for complete abstract]

Double-blind comparison of rectally administered diazepam to placebo for pediatric sedation: the cardiovascular response.

The sedative and cardiovascular effects of rectally administered diazepam (0.6 mg/kg) were compared to placebo in uncooperative children who required sedation during dental treatment. Twelve healthy preschool children, who required amalgam restorations, were treated during two standardized restorative appointments in a double-blind, crossover study. Blood pressure and pulse were obtained during four specified intervals during the appointment. The behavior of the children during the treatment visits was videotaped and later statistically analyzed using a kinesics/vocalization instrument. Behavioral ratings of cooperation were significantly improved during the treatment visit following diazepam. All interfering bodily movements, patient vocalizations and operator commands for the diazepam group were reduced significantly (p≤0.0001). No significant differences were observed for noninterfering behavioral response. Rectally administered diazepam did not alter blood pressure or pulse significantly in these sedated children when compared to the placebo. These findings indicate that rectal diazepam is an effective sedative agent with minimal effect on the cardiovascular system for the management of the young pediatric dental patient.

Sulforaphane improves cognitive function administered following traumatic brain injury.

Recent studies have shown that sulforaphane, a naturally occurring compound that is found in cruciferous vegetables, offers cellular protection in several models of brain injury. When administered following traumatic brain injury (TBI), sulforaphane has been demonstrated to attenuate blood-brain barrier permeability and reduce cerebral edema. These beneficial effects of sulforaphane have been shown to involve induction of a group of cytoprotective, Nrf2-driven genes, whose protein products include free radical scavenging and detoxifying enzymes. However, the influence of sulforaphane on post-injury cognitive deficits has not been examined. In this study, we examined if sulforaphane, when administered following cortical impact injury, can improve the performance of rats tested in hippocampal- and prefrontal cortex-dependent tasks. Our results indicate that sulforaphane treatment improves performance in the Morris water maze task (as indicated by decreased latencies during learning and platform localization during a probe trial) and reduces working memory dysfunction (tested using the delayed match-to-place task). These behavioral improvements were only observed when the treatment was initiated 1h, but not 6h, post-injury. These studies support the use of sulforaphane in the treatment of TBI, and extend the previously observed protective effects to include enhanced cognition.

TIME DEPENDENT ALTERATIONS IN CENTRAL NERVOUS SYSTEM DOPAMINE RECEPTORS INDUCED BY DOPAMINE AGONIST TREATMENT

Levodopa, the precursor of dopamine, is currently the drug of choice in the treatment of Parkinson's disease. Recently, two direct dopamine agonists, bromocriptine and pergolide, have been tested for the treatment of Parkinson's disease because of reduced side effects compared to levodopa. Few studies have evaluated the effects of long-term treatment of dopamine agonists on dopamine receptor regulation in the central nervous system. Thus, the purpose of this study was to determine whether chronic dopamine agonist treatment produces a down-regulation of striatal dopamine receptor function and to compare the results of the two classes of dopaminergic drugs.^ Levodopa with carbidopa, a peripheral decarboxylase inhibitor, was administered orally to rats whereas bromocriptine and pergolide were injected intraperitoneally once daily. Several neurochemical parameters were examined from 1 to 28 days.^ Levodopa minimally decreased striatal D-1 receptor activity but increased the number of striatal D-2 binding sites. Levodopa increased the V(,max) of tyrosine hydroxylase (TH) in all brain regions tested. Protein blot analysis of striatal TH indicated a significant increase in the amount of TH present. Dopamine-beta-hydroxylase (DBH) activity was markedly decreased in all brain regions studied and mixing experiments of control and drug-treated cortices did not show the presence of an increased level of endogenous inhibitors.^ Bromocriptine treatment decreased the number of D-2 binding sites. Striatal TH activity was decreased and protein blot analysis indicated no change in TH quantity. The specificity of bromocriptine for striatal TH suggested that bromocriptine preferentially interacts with dopamine autoreceptors.^ Combination levodopa-bromocriptine was administered for 12 days. There was a decrease in both D-1 receptor activity and D-2 binding sites, and a decrease in brain HVA levels suggesting a postsynaptic receptor action. Pergolide produced identical results to the combination levodopa-bromocriptine studies.^ In conclusion, combination levodopa-bromocriptine and pergolide treatments exhibited the expected down-regulation of dopamine receptor activity. In contrast, levodopa appeared to up-regulate dopamine receptor activity. Thus, these data may help to explain, on a biochemical basis, the decrease in the levodopa-induced side effects noted with combination levodopa-bromocriptine or pergolide therapies in the treatment of Parkinson's disease. ^

Tolerance of allografts across MHC barriers by allochimeric class I MHC proteins

Class I MHC proteins have been shown to induce accelerated rejection or prolong survival of allografts in various experimental models. These immunological effects have been attributed to the highly polymorphic alpha helical regions of the extracellular portions of the class I MHC molecule. The present experiments were designed to elucidate the immunomodulatory effects of these polymorphic regions and delineate the mechanisms involved. Soluble allochimeric class I MHC proteins were produced by substituting the PVG class I MHC RT1.Ac amino acid residues within the a 1 helical region with those of the donor BN ( a 1hn-RT1.Ac), the a 2 helical region of BN ( a 2hn-RT1.Ac), and both the a 1 and a 2 helical regions (RT1.An). The class I MHC proteins were produced in an E. coli protein expression system. The a 2hn-RT1.Ac and RT1.An proteins, when administered subcutaneously into PVG hosts 7 days prior to transplantation, resulted in accelerated rejection of BN cardiac allografts. The a 1hn-RT1.Ac construct did not demonstrate such immunogenic effects. Intra-portal administration of a 1hn-RT1.Ac or RT1.An, in combination with perioperative CsA, induced tolerance to BN cardiac allografts. The a 1hn-RT1.Ac protein was able to induce tolerance in a larger majority of the PVG recipients and at a lower dose of protein when compared to the RT1.An protein. RT1.An administered orally to PVG recipients also induced long term survival of cardiac allografts. In vitro analysis revealed that lymphocytes from tolerant hosts were hyporesponsive to donor splenocytes, but responsive to 3rd party splenocytes. Evaluation of T cell cytokine expression patterns revealed that rejector PVG hosts displayed a Type I T-cell response when re-challenged with donor splenocytes, in contrast to tolerant animals that displayed a Type II T-cell response. FACS analysis of the T cells revealed that the ratio of CD4 to CD8 cells was 3:1 and was consistent in the groups tested suggesting a complex interaction between the subsets of T cells, yielding the observed results. Histologic analysis of the cardiac allografts revealed that tolerant PVG hosts maintained BN cardiac allografts without any evidence of acute or chronic rejection after 300 days post transplant. This body of work has demonstrated that the use of soluble donor/recipient allochimeric class I MHC proteins with a short peri-operative course of CsA resulted in transplant tolerance. This treatment regimen proffers a clinically relevant approach to the induction of tolerance across MHC barriers. ^

INACTIVATION OF MUTAGENIC DRUGS AND THEIR METABOLITES IN THE URINE OF PATIENTS ADMINISTERED ANTINEOPLASTIC THERAPY

Urines from patients administered mutagenic antineoplastic drugs were significantly mutagenic in the Ames assay, and hence may pose a genotoxic hazard to hospital personnel or family members caring for the patient. The urines were tested for mutagenicity in several different strains of Salmonella typhimurium that were uvr positive or negative (TA98, TA100, TA102, UTH8413, UTH8414). The urines were fractionated by high pressure liquid chromatography (HPLC) and the fractions assayed for mutagenicity in the strains in which the whole urine was mutagenic. Only fractions of urines containing the parent compound (cisplatin, doxorubicin, or mitomycin) were mutagenic; no other fraction showed significant mutagenicity. However, urine containing cyclophosphamide had two fractions that were mutagenic. One fraction, the fraction containing cyclophosphamide, required metabolic activation for mutagenicity. The other fraction did not require activation for mutagenicity.^ The chemical and mutagenic stability of these urines at room temperature was assayed over a 14 day period. The parent compound degraded within the first seven days, but the urines remained mutagenic. Cis-platinum was chemically stable in the urine; however, the urine decreased in mutagenicity. The decrease was probably the result of stable ligands binding to the platinum.^ Inactivation methods were developed to reduce the genotoxic hazard. Urine containing cisplatin was inactivated by complexing the cisplatin with diethyldithiocarbamate (DDTC). Oxidation with NaOCl of urines containing mitomycin and doxorubicin (sodium thiosulfate must be added to the doxorubicin urine) results in mutagenic inactivation. Inactivation of urine containing cyclophosphamide requires oxidation with alkaline potassium permaganate and trapping of active degradation products with sodium thiosulfate. Urines containing these drugs can be inactivated, but not always by the same method that inactivates the drug alone in solution. Therefore, in the future development of inactivation methods, both chemical and mutagenic assays are necessary to determine effectiveness. Methods of inactivation of mutagenic excreta developed in this study are both effective and practical. ^