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Biomedical subjects

J Williams

Publications and source records attributed to J Williams.

At least 613 records · Page 34Linked to original sources
PubMed1993

Dose-related suppression of REM sleep and PGO waves by the serotonin-1 agonist eltoprazine.

Parental administration of the serotonin-1 agonist eltoprazine (0.0625 to 4.0 mg/kg [0.0002 to 0.016 mmol/kg]) in freely moving cats produced significant suppression of electrophysiologic rapid eye movement (REM) sleep signs, ponto-geniculo-occipital (PGO) activity, and REM sleep behavior. The virtual total suppression of REM sleep (0.4%, 4.0 mg/kg) and PGO wave activity (2 to 4 mg/kg) in exchange for increasing amounts of non-REM (NREM) slow-wave sleep was a dose-dependent function of the amount of eltoprazine administered. Wakefulness was unaffected by eltoprazine regardless of dose. Concurrent with this dose-dependent suppression of REM was a dose-dependent increase in electroencephalographic synchrony and mean electromyographic amplitude. Since eltoprazine was found to shift the balance between REM and NREM sleep but did not change the balance between sleep and waking, it is a potentially useful tool for the investigation of serotonergic-cholinergic interaction.

Animals↗
PubMed1993

Effects of sex-linked imperfect albinism in the chicken (sal-c) on plasma luteinising hormone concentrations and early egg production.

1. When measured before and after the onset of darkness, plasma LH concentrations in 40-day-old sex-linked albino pullets (sal-c) were slightly lower than those of nonalbinos (s+). 2. This finding prompted an experiment in which plasma LH concentrations were measured between 12 and 33 weeks of age when daylength was increased at 15 or 21 weeks. Egg production of the early and late maturing albino hens was measured. 3. Plasma LH concentrations overall and at 17 weeks were lower for albinos than for nonalbinos. In the early maturing group egg production of albinos was higher than that of nonalbinos. 4. Results suggest that increased egg production of albinos is not the direct result differences in plasma LH concentrations but may be a consequence of differences in the control of LH secretion.

Albinism↗
PubMed1993

Feeding status affects glucose metabolism in exercising horses.

Four standardbred horses were used in a Latin square design experiment to evaluate the effects of feeding status on metabolic response to exercise. Horses were deprived of food overnight and then fed 0 (control condition), 1, 2 or 3 kg of corn grain approximately 2.5-3 h before exercise. The exercise test consisted of a warm-up phase (heart rate mean = 144 beats/min) followed by 800 m of walking and then a high intensity work bout for 1600 m (heart rate mean = 206 beats/min). All tests were conducted on a high speed equine treadmill on which the horses had been previously conditioned. During exercise, the control treatment resulted in steady plasma glucose concentrations, whereas all other treatments (1, 2 or 3 kg corn) caused a decline in plasma glucose. Liver glycogen concentration was decreased by exercise in the horses only when they received the control treatment. Plasma lactate concentration was increased by exercise but was not affected by feeding state. Plasma free fatty acid concentrations were highest when the horses received the control treatment. In addition, when horses received the control treatment, plasma free fatty acid concentrations decreased during the warm-up and high intensity phases of the test and increased during the walk phase. Free fatty acid concentrations changed in the horses receiving 1, 2 or 3 kg of corn grain only during the high intensity phase of the exercise test. Feeding status affects the metabolic response of horses to exercise thus further studies are necessary to evaluate the effect of feeding status on exercise performance.

Analysis of Variance↗
PubMed1993

Influence of HLA matching on rejections and short- and long-term primary cadaveric allograft survival.

Distribution of cadaveric donor kidneys, based upon the donor-recipient HLA match grade, remains one of the major controversies in transplantation. To determine whether matching results in fewer rejection episodes and better graft survival, we retrospectively studied our single-center patient population of 683 cyclosporine-prednisone-treated primary cadaveric renal allograft recipients. For 237 recipients of well-matched HLA A, B kidneys (< or = 2 HLA A, B mismatches [MM]) the 1-, 3-, 5-, and 7-year graft survivals of 76%, 66%, 62%, and 61%, respectively, were not significantly different from those of 71%, 65%, 63%, and 63%, respectively, for the 446 poorly matched HLA A, B (> 2 HLA A, B MM) recipients. Similarly, the 1-, 3-, 5-, and 7-year graft survivals for the 307 recipients of well-matched HLA-DR kidneys (0 or 1 DR MM) of 74%, 65%, 63%, and 61%, respectively, were not significantly different from those of 72%, 65%, 63%, and 62%, respectively, for the 366 poorly matched (2 DR MM) recipients. Patient survivals were comparable at each time point for well- vs. poorly matched recipients. Similarly, donor-recipient HLA A, B, and DR matching was not beneficial in retransplant recipients who were transplanted following negative NIH and antiglobulin (AHG) crossmatches when testing both historical (high-PRA) and pretransplant sera. Since rejection episodes may be a more sensitive indicator of immune response than graft loss, we also analyzed the relationship between donor-recipient HLA match grade and posttransplant rejections. A total of 60% (n = 413) of recipients experienced no rejections and had 1-, 3-, 5-, and 7-year graft survivals of 82%, 78%, 74%, and 73%, respectively; 32% (n = 215) of patients who experienced 1 rejection had 1-, 3-, 5-, and 7-year graft survivals of 58%, 48%, 44%, and 43%, respectively (P < 0.001 for graft survival of 0 vs. 1 rejection). The remaining 8% (n = 55) of recipients experienced more than 1 (> 1) rejection and had 1-, 3-, 5-, and 7-year graft survivals of 62%, 38%, 36%, and 36%, respectively (P < 0.001 for graft survival of 0 vs. > 1 rejection and P < 0.01 for graft survival of 1 vs. > 1 rejection). The mean numbers of rejections/patient experienced by well-matched vs. poorly matched recipients were comparable and not significantly different.(ABSTRACT TRUNCATED AT 400 WORDS)

Blood Transfusion↗
PubMed1993

Septo-optic dysplasia: the clinical insignificance of an absent septum pellucidum.

Neurodevelopmental assessments were performed on seven patients with optic nerve hypoplasia and absence of the septum pellucidum on MRI. The evaluation included neurological status, language development, neuropsychological functioning, and behavioral and emotional adjustment. Six of the seven were found to have normal cognitive development, intact neurological status, normal language development and age-appropriate behavior. Abnormal findings included early poor motor coordination, which was felt to be closely related to decreased visual acuity, as well as subtle visual attentional problems which occurred even in patients who had normal vision in one eye. Congenital absence of the septum pellucidum was not associated with significant intellectual, behavioral or neurological deficits in the majority of these patients.

Achievement↗
PubMed1993

The E1B 19-kilodalton protein is not essential for transformation of rodent cells in vitro by adenovirus type 5.

The newly constructed adenovirus type 5 mutant in1 carries a single AT base pair insertion immediately after nucleotide position 1715 in the E1B gene sequence which destroys the proximal AUG normally present in E1B messages and prevents production of intact E1B 19-kDa protein in infected cells. We have used in1, variants of in1 containing mutant alleles of viral genes known to enhance transformation frequency, and adenovirus type 5 mutant dl337 (S. Pilder, J. Logan, and T. Shenk, J. Virol. 52:664-671, 1984), in which the sequence between nucleotides 1770 and 1916 within the 19-kDa reading frame is deleted, to test the generally accepted hypothesis that this E1B protein is essential for the transformation of rodent cells and maintenance of the transformed phenotype. We find that these mutants transform rat embryo cells, rat kidney and mouse kidney primary cells, and cells of the 3Y1 rat line with decreased frequencies only when virus is added to these various cells at high input multiplicities of infection. In contrast, when lower doses of virus are used, the mutants transform with wild-type frequencies. Cells infected with higher doses of mutant virus show increased levels of DNA degradation and cell killing compared with those of cells infected with the same levels of wild-type virus, and these effects most likely contribute to the decreased transformation frequencies observed. On the basis of these results and the results of phenotypic analyses of numerous transformants, we propose that the E1B 19-kDa protein is not required for induction and/or maintenance of transformed-cell characteristics in rodent cells infected with adenovirus type 5.

Adenoviridae↗
PubMed1993

Prognostic value of epidermal growth factor receptor expression in cervical carcinoma.

AIMS: To investigate the pattern of epidermal growth factor receptor expression and its prognostic value in the three main types of cervical carcinoma. METHODS: 62 cases of stage IB/IIA cervical carcinoma, all with a minimum of five years of follow up, were studied. Representative sections were stained for mucin to permit accurate tumour typing and a standard avidin-biotin immunoperoxidase technique using the polyclonal antibody 12E was used to demonstrate the presence of epidermal growth factor receptor. RESULTS: A proportion of all three tumour types expressed epidermal growth factor receptor, it being most common in squamous cell carcinomas (50%). Overall, there was a correlation between epidermal growth factor expression and mortality. This was particularly obvious in the absence of lymph node metastases. When the individual tumour types were considered this association with prognosis was not demonstrable for squamous cell carcinomas or adenocarcinomas but was a very prominent feature of adenosquamous carcinomas. CONCLUSIONS: Immunohistochemical demonstration of epidermal growth factor receptor expression may be useful in identifying those patients with a poor prognosis, particularly those with adenosquamous carcinomas which have not metastasised to the regional lymph nodes.

Adenocarcinoma↗
PubMed1993

Effect of inhaled prostaglandin E2 on allergen-induced asthma.

Prostaglandin E2 (PGE2) is produced in the lung but unlike most other lipid mediators has potentially important antiallergic effects. Whether these properties are relevant to asthma has not been established. The effect of inhaled PGE2 on allergen-induced asthma was examined in a double-blind crossover study of eight subjects with asthma. In Study 1 subjects inhaled 100 micrograms PGE2 or placebo 5 min before a normal saline challenge, and FEV1 and bronchial reactivity to methacholine was measured at intervals for 7 h. In Study 2, which had a similar design, subjects inhaled the same dose of PGE2 or placebo followed by a dose of allergen previously shown to cause a fall in FEV1 of 20% or more. On the normal saline challenge day inhaled PGE2 caused a small increase in FEV1 that lasted for around 60 min; there was no difference in the provocative dose of methacholine causing a 20% fall in FEV1 (PD20) at 4 and 7 h compared with placebo. PGE2 caused marked inhibition of the early and late response to allergen. The mean maximum fall in FEV1 0 to 2 h after allergen was 37.8 and 7.7% with placebo and PGE2 pretreatment, respectively (mean difference 30%; 95% CI 15, 45%; p < 0.005). The mean maximum fall in FEV1 from 4 to 7 h after allergen was 25.5 and 8.8% respectively (mean difference 16.7%; 95% CI 4, 29%; p < 0.02). The methacholine PD20 fell significantly after allergen with placebo but not with PGE2. The difference was 1.5 doubling doses at both 4 and 7 h (p < 0.01 and p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1993

The development of a radioimmunoassay for reverse triiodothyronine sulfate in human serum and amniotic fluid.

Sulfated iodothyronines including T4-sulfate (T4S) and T3-sulfate (T3S) have been identified in human serum and amniotic fluid. Little is known, however, about the existence of sulfate conjugation of reverse T3 (rT3S) in man. In this report, we employed a novel, sensitive, and specific rT3S RIA to address this question. The rabbit antiserum to rT3S was highly specific; T4, T3, rT3, and 3,3'-T2 showed less than 0.002% cross-reaction with the antiserum. Only T4S and T3S cross-reacted significantly (0.3% and 0.01%, respectively); other analogs cross-reacted less than 0.0001%. The detection threshold of the RIA was 14 pmol/L (1.0 ng/dL). The mean serum rT3S concentration (pmol/L) was 40 in euthyroid subjects. Values were similar in hypothyroid patients (38) and pregnant women (52) but significantly (P < 0.01) elevated to 176 in hyperthyroid patient, 74 in patients with nonthyroid illnesses, and 684 in cord sera of newborns. Serum rT3S increased significantly in hyperthyroid patients 1 day after administration of 1 g sodium ipodate orally. Reverse T3S was detected consistently in amniotic fluid at 14 to 22 weeks of gestation and showed a marked rise 1-3 weeks after intraamniotic administration of 500-1000 micrograms T4. The various data suggest that: (1) rT3S is a normal component of human serum and amniotic fluid; (2) it is derived from metabolism of T4 or rT3; (3) circulating rT3S increases in hyperthyroidism and in circumstances where type I 5'-monodeiodinating activity is low, e.g. nonthyroid illnesses, fetal life, and after administration of ipodate.

Amniotic Fluid↗
PubMed1993

Use of nonverbal tests to screen for writing dysfluency in school-age children.

Writing fluency, the ability to write rapidly and easily, is critical for the timely completion of written assignments in the classroom. Children who possess basic writing skills and have an ability to communicate ideas are often penalized for slowness in completing written tasks. The present study used frequently administered nonverbal tasks to predict performance on the Writing Fluency subtest of the Woodcock-Johnson Tests of Achievement--Revised for 146 subjects from 6 to 16 years old. A stepwise-regression analysis indicated the Coding subtest of the WISC--R, Beery Developmental Test of Visual Motor Integration, the Grooved Pegboard, and gender accounted for 32% of the variance. Logistic regression suggested cut-off scores falling one standard deviation below the mean on Coding and Beery's visuomotor test would signal need for further evaluation of writing dysfluency, particularly for boys.

Adolescent↗
PubMed1993

Medicare home health: a description of total episodes of care.

The purpose of this study was to present descriptive information on the characteristics of 2,873 Medicare home health clients, to quantify systematically their patterns of service utilization and allowed charges during a total episode of care, and to clarify the bivariate associations between client characteristics and utilization. The model client was female, 75-84 years of age, living with a spouse, and frail based on a variety of indicators. The mean total episode was approximately 23 visits, with allowed charges of $1,238 (1986 dollars). Specific subgroups of clients, defined by their morbidities and frailties, used identifiable clusters of services. Implications for case-mix models and implications for capitation payments under health care reform are discussed.

Aged↗
PubMed1993

Effects of frontal cortical lesions on mouse striatum: reorganization of cell recognition molecule, glial fiber, and synaptic protein expression in the dorsomedial striatum.

Brain injury induces trophic effects within adjacent tissue through an unknown molecular mechanism. One model of this lesion effect involves the enhanced outgrowth of neuronal processes from transplanted substantia nigra in animals with cerebral cortex lesions. Since cell recognition molecules are involved in the molecular mechanisms of contact between cells and surrounding extracellular matrix components, and are important in plasticity of the nervous system, we investigated changes in L1, N-CAM, and tenascin, as well as synapse-associated proteins and gliosis, in the striatum of mice with cortical lesions. The removal of somato-sensory and motor cortex would be expected to produce changes predominantly in the dorsal striatum. Lesioned mice, however, showed a significant enhancement of both L1 and N-CAM immunostaining intensity only within the most medial-periventricular and dorsomedial parts of the striatum, as compared to the nonlesioned side. Tenascin expression was significantly decreased, but only in the most medial part of the striatum. The changes in intensity of immunostaining with L1, N-CAM, and tenascin did not diminish with time after lesioning. These changes in cell recognition molecule expression indicate a possible molecular basis of lesion-induced plasticity in neuronal circuits within the dorsomedial striatum. These changes were accompanied by decreased synapsin and synaptophysin expression, but without any significant change in neurofilament expression. In contrast, glial fibrillary acidic protein and vimentin immunoreactivities were increased in almost the entire striatum on the lesioned side. Therefore, the areas of changes in cell recognition molecule expression did not simply correlate to the increased astrogliosis or neuronal fiber damage. We postulate that the periventricular dorsomedial striatum is relatively sensitive to disturbances of corticostriatonigral circuits and, simultaneously, this striatal area has a unique ability to support and promote neurite growth.

Animals↗
PubMed1993

Interacting signalling pathways regulating prestalk cell differentiation and movement during the morphogenesis of Dictyostelium.

Analysis of the expression patterns of two genes encoding extracellular matrix proteins shows there to be an unexpectedly complex pattern of prestalk cell differentiation and movement during the morphogenesis of Dictyostelium. The organism employs both cell sorting and positional differentiation to generate a patterned structure but these two mechanisms are used at different times during development. During slug formation prestalk cells arise at scattered positions within the aggregate and then move to its apex to form the tip. In contrast, during culmination, stalk cell differentiation occurs in a positionally localized manner at the entrance to the stalk tube. Two interacting signalling pathways regulate the differentiation of prestalk and stalk cells. Prestalk cell differentiation is induced by DIF, a chlorinated hexaphenone, and a repression mechanism prevents DIF acting to induce premature stalk cell differentiation during slug migration. At culmination intracellular cAMP levels rise, the cAMP dependent protein kinase (PKA) is activated and the block to stalk cell differentiation is lifted. Activation of PKA is also necessary in order that prestalk cells move to the entrance of the stalk tube at culmination. Thus, in Dictyostelium, PKA plays a role both in the regulation of cellular differentiation and in morphogenetic cell movement.

Animals↗
PubMed1993

The use of neuropsychological data to detect altered neurological functioning in a child with myelomeningocele.

Although children with myelomeningocele often display atypical patterns on psychometric testing, this case study demonstrates the sensitivity of neuropsychological instruments to detect altered neurological functioning in a patient with spina bifida. The subject had a history of myelomeningocele at the lumbosacral level and placement of a ventriculoperitoneal shunt. During a routine neuropsychological evaluation, a 44-point discrepancy between his verbal (verbal IQ = 98) and nonverbal abilities (performance IQ = 54) on the Wechsler Intelligence for Children-Revised was found. In comparison to high average academic achievement, test findings suggested depressed memory skills and extreme slowing in psychomotor speed. A pattern of acute decline in overall cognitive functioning was suggested. Magnetic resonance imaging revealed a left frontoparietal brain mass, which was surgically removed. Follow-up neuropsychological testing 9 months postsurgery indicated an increase in nonverbal intelligence with improved psychomotor speed and information processing. This case study illustrates the importance of obtaining baseline evaluations in this neurologically high-risk population as well as the clinical usefulness of psychometric data in diagnostic workups.

Brain Neoplasms↗
PubMed1993

Effect of aspirin on the contractility of aortic rings in vitro from spontaneously hypertensive rats.

The effect of Acetylsalicylic acid (ASA) on the responsiveness of rat aortic smooth muscle was investigated by comparing the contractility of aortic rings from SHR and WKY rats in response to alpha-agonist, phenylephrine (PE). Cumulative dose response curves for PE were generated from aortic rings of SHR and WKY rats in the presence and absence of 0.2mM ASA. To investigate the involvement of endothelium on ASA mediated effects, active tension was recorded for denuded and non-denuded rings from SHR animals in response to KCl and PE. Denuded and non-denuded aortic rings from SHR animals in the presence of ASA produced significantly higher active tension than in the absence of ASA. The reactivity of aortic rings from WKY control animals was not altered significantly in the presence of ASA. These studies suggest that ASA can also modulate aortic contractility through other mechanism(s) in addition to its effect on the metabolites of arachidonic acid. Significance of these observations is discussed below.

Animals↗