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Biomedical subjects

J Hawkins

Publications and source records attributed to J Hawkins.

At least 19 recordsLinked to original sources
PubMed1992

Substituent variation in azabicyclic triazole- and tetrazole-based muscarinic receptor ligands.

The effect of variation of the 1-azabicyclic substituent on the novel 1,2,3-triazol-4-yl-, 1,2,4-triazol-1-yl, tetrazol-5-yl-, and tetrazol-2-yl-based muscarinic receptor ligands has been studied, and the exo-azabicyclic[2.2.1]hept-3-yl substituent was found to give the most potent and efficacious compounds. In addition, variation of the second substituent on 1,2,4-triazol-1-yl- and tetrazol-2-yl-based muscarinic receptor ligands has yielded a series of novel compounds with high potencies and efficacies, ranging from full agonists to antagonists. Small lipophilic electron withdrawing substituents give potent but low efficacy compounds, while small polar electron donating substituents give potent and efficacious compounds. The activity of these compounds is described in terms of a model of the receptor involving lipophilic and hydrogen bonding interactions. These compounds provide muscarinic ligands with high potency and a range of efficacies suitable for testing as candidate drugs in the treatment of Alzheimer's disease.

Alzheimer Disease↗
PubMed1992

Synthesis and muscarinic activities of quinuclidin-3-yltriazole and -tetrazole derivatives.

The synthesis of 15 methyl or unsubstituted 1,2,3-triazoles, 1,2,4-triazoles, and tetrazoles additionally substituted with a 1-azabicyclo[2.2.2]octan-3-yl group is described. The potency and efficacy of these compounds as muscarinic ligands were determined in radioligand binding assays using [3H]oxotremorine and [3H]quinuclidinyl benzilate. Potency and efficacy were found in compounds in which the azole moiety was attached to the azabicyclic ring either through a carbon atom or a nitrogen atom. Electrostatic potential maps of both the C-linked and the novel N-linked series of compounds were calculated. A relationship between position and depth of the electrostatic minima relative to the azabicyclic ring and the potency and efficacy of the compounds was determined.

Animals↗
PubMed1992

Self-reported sleep quality in college students: a repeated measures approach.

A longitudinal assessment of sleep quality is presented. Undergraduates provided two levels of repeated measures data. Sleep log information was gathered across the 7 days of the week, in three replications, over a semester. There were several new findings. Across the week, students spent significantly more time in bed on weekend days as compared with weekdays. Further, a new measure for quality of sleep covaried with the amount of time spent in bed during the week. The students enjoyed their sleep more on the weekends. Finally, both the amount of time in bed and the number of awakenings reported dropped significantly as the semester progressed.

Adolescent↗
PubMed1992

Identification of spinal cord polypeptides related to glial fibrillary acidic protein (GFAP).

Spinal cord cytoskeletal preparations from three different mammalian species contain several polypeptides in the SDS-PAGE molecular weight range 100-220 kDa which are recognized by all members of a panel of antibodies to glial fibrillary acidic protein (GFAP) and by anti-IFA, a panspecific intermediate filament protein antibody. The polypeptides are not recognized by antibodies to other intermediate filament proteins or to ubiquitin. The proteins coelute with GFAP in ion-exchange chromatography, cosediment with GFAP under filament assembly conditions, produce similar chemical digest patterns and have an amino acid profile close to that of pure GFAP, all properties expected for covalent GFAP multimers. Further experiments provide evidence for the existence of such multimeric complexes in vivo.

Amino Acids↗
PubMed1979

Intrathoracic meningoceles and neurofibromatosis.

We describe here four additional cases of intrathoracic meningoceles associated with neurofibromatosis, bringing the total number of reported cases of thoracic meningoceles to 88. Seventy-five (85%) have been associated with neurofibromatosis. Possibly, both dural and regional vertebral dysplasia are intrinsic to neurofibromatosis and contribute to the development of the meningocele.

Adult↗
PubMed1979

Handedness and sleep duration.

The differences in habitual sleep duration and absolute deviations in habitual sleep duration from the normative mean between 60 left-, 36 mixed- and 125 right-handed college students were tested. It was found that mixed-handers tend to sleep less and as a group show significantly greater deviations in habitual sleep durations than either left- or right-handers. The heuristic value of this relationship for future research was discussed briefly.

Functional Laterality↗
PubMed1979

Pain thresholds in rats during recovery from REM sleep deprivation.

Using 30 Sprague-Dawley female rats, threshold to pain was measured over the course of recovery from REM sleep deprivation. Relative to the untreated controls and to their own pretreatment thresholds, the REM-deprived animals showed significantly reduced pain thresholds which were still evident 96 hours after the termination of the REM deprivation. Possible implications of these data for research with analgesic drugs were noted.

Animals↗
PubMed1978

Self-reported consistency of normal habitual sleep durations of college students.

A relationship between hours of sleep/night and the consistency of this normal daily sleep duration was observed for 763 college students who had rated themselves as good sleepers with stable and fairly well established patterns of sleep. Congruent with a limited literature, these data suggest that shorter sleep durations are likely, for college students, to be relatively recently acquired patterns of sleep.

Circadian Rhythm↗
PubMed1977

Decision to admit. Criteria for admission and readmission to a Veterans Administration hospital.

Factors related to the decision to hospitalize applicants for psychiatric treatment at a Veterans Administration hospital were explored. For a three-week period, decision makers completed questionnaires following interviews with applicants. It was found that 79% of applicants were "revolving door" patients. These patients were much less likely to be married, and more likely to be homeless and diagnosed as schizophrenic, than patients without previous hospitalizations. A small number of patients were admitted because of characteristics of their illness regardless of their social situations. Patients were not hospitalized on the basis of social or nonpsychiatric criteria alone. A large number were admitted because of a combination of factors, some social in nature and others related to their psychopathology. A social process taking place in the screening interview appeared to have some influence in the decision to admit.

Decision Making↗
PubMed1977

Purification and properties of L-glutaminase-L-asparaginase from Pseudomonas acidovorans.

An enzyme that catalyzes the hydrolysis of both glutamine and asparagine has been purified to homogeneity from extracts of Pseudomonas acidovorans. The enzyme having a ratio of glutaminase to asparaginase of 1.45:1.0 can be purified by a relatively simple procedure and is stable upon storage. The glutaminase-asparaginase has a relatively high affinity for L-asparagine (Km=1.5 X 10(-5) M) and L-glutamine (Km=2.2 X 10(-5) M) and has a molecular weight of approximately 156,000 the subunit molecular weight being approximately 39,000. Injections of the enzyme produced only slight increases in the survival time of C3H/HE mice carrying the asparagine-requiring 6C2HED Gardner lymphoma and of white Swiss mice carrying the glutamine-requiring Ehrlich lymphoma.

Amidohydrolases↗