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Biomedical subjects

A Conway

Publications and source records attributed to A Conway.

At least 19 recordsLinked to original sources
PubMed1999

Physostigmine challenge before and after chronic cholinergic blockade in elderly volunteers.

BACKGROUND: As a test of possible muscarinic up-regulation, the cortisol response to intravenous (i.v.) physostigmine (an anticholinesterase) was measured in 9 elderly volunteers before and after chronic cholinergic blockade with the muscarinic cholinergic antagonist scopolamine. METHODS: Each of the 9 elderly control subjects was given two physostigmine (0.5 mg i.v.) infusions separated by 21 doses of nightly scopolamine (1.2 mg p.o.). No scopolamine was administered the night before infusions, and glycopyrrolate (0.2 mg i.v.) was administered prior to physostigmine, to block its peripheral effects. Vital signs were monitored and blood samples were collected at six time points surrounding the physostigmine infusion (-10, +10, +20, +30, +50, and +70 min). Behavioral measures and cognitive tests were administered prior to and 30 min after the physostigmine. RESULTS: The cortisol response to physostigmine was greater after the second (post-chronic scopolamine) infusion study compared to the first (p < .05) as measured by an area under the curve analysis of all time points. When individual time points were compared, the mean cortisol response was significantly increased after the second physostigmine infusion at the +50- and +70-min time points (p < .05). There were no significant changes in behavioral rating scales, cognitive tests, or vital signs between the two physostigmine infusion study days. CONCLUSIONS: This study demonstrates increased hypothalamic-pituitary-adrenocortical axis responsivity to a central nervous system cholinergic stimulus after chronic muscarinic blockade in 9 elderly control subjects. It also gives further evidence to support previous suggestions of muscarinic plasticity, specifically postsynaptic up-regulation, in the aging brain following exposure to chronic anticholinergic treatment.

Aged↗
PubMed1999

Antimutagenic activity of chemical fractions isolated from a commercial soybean processing by-product.

Commercial products of agronomic crop plants may become a reliable and inexpensive source of phytonutrients, such as antimutagenic food supplements. We previously demonstrated that PCC, an ethanol extract of a commercial soybean processing by-product, was able to repress induced genomic DNA damage, whole cell clastogenicity, and point mutation in mammalian cells. In this paper we separated PCC into a series of chemically defined fractions and determined their ability to repress induced mutagenic damage in Chinese hamster lung cells, Chinese hamster ovary cells and human lymphocytes. Fraction PCC70 (PCC 70% methanol eluate) contained the flavonoids from PCC and daidzin and genistin repressed 2-acetoxyacetylaminofluorene (2AAAF)-induced DNA damage measured with single cell gel electrophoresis. Genistein, however, enhanced the genotoxic impact of 2AAAF. Fraction PCC100 (PCC 100% methanol eluate) had the greatest level of antigenotoxic activity against 2AAAF in CHO cells and repressed the genotoxic capacity of the dietary carcinogen 2-amino-3-methylimidazo-(4,5-f)quinoline (IQ) in human lymphocytes. These data indicate that commercial soybean products and by-products may be a source of chemoprotective food additives.

Animals↗
PubMed1998

A genome-wide transcriptional analysis of the mitotic cell cycle.

Progression through the eukaryotic cell cycle is known to be both regulated and accompanied by periodic fluctuation in the expression levels of numerous genes. We report here the genome-wide characterization of mRNA transcript levels during the cell cycle of the budding yeast S. cerevisiae. Cell cycle-dependent periodicity was found for 416 of the 6220 monitored transcripts. More than 25% of the 416 genes were found directly adjacent to other genes in the genome that displayed induction in the same cell cycle phase, suggesting a mechanism for local chromosomal organization in global mRNA regulation. More than 60% of the characterized genes that displayed mRNA fluctuation have already been implicated in cell cycle period-specific biological roles. Because more than 20% of human proteins display significant homology to yeast proteins, these results also link a range of human genes to cell cycle period-specific biological functions.

Cell Cycle↗
PubMed1998

The Australian Multicenter Trial of Growth Hormone (GH) Treatment in GH-Deficient Adults.

GH treatment in adults with GH deficiency has numerous beneficial effects, but most studies have been small. We report the results of an Australian multicenter, randomized, double-blind, placebo-controlled trial of the effects of recombinant human GH treatment in adults with GH deficiency. GH deficiency was defined as a peak serum GH of < 5 mU/liter in response to insulin-induced hypoglycemia. Patients were randomly assigned to receive either GH (0.125 U/kg per week for 1 month and 0.25 U/kg per week for 5 months) or placebo. After 6 months, all patients received GH. The primary end points were biochemical responses, body composition, quality of life, and safety. One hundred sixty-six patients (72 females and 91 males) with a mean age of 40 +/- 1 yr (+/- SEM; range 17-67 yr) were recruited. Serum insulin-like growth factor-I (IGF-I) increased from a standard deviation score of -2.64 +/- 0.27 (range -8.8 +3.82; n = 78) to +1.08 +/- 2.87 (range -7.21 to +6.42) at 6 months in the GH/GH group; 38% of the whole group were above the age-specific reference range following treatment [17.6% and 68.9% with subnormal (< 2 SD) or normal (+/- 2 SD) pretreatment levels, respectively]. Fasting total cholesterol (P = 0.042) and low-density lipoprotein cholesterol (P = 0.006) decreased over the first 6 months. Fat-free mass increased in the first 6 months whether measured by bioelectrical impedance (P < 0.001) or dual energy x-ray absorptiometry (DEXA; P < 0.001). Total-body water increased in the first 6 months whether measured by bioelectrical impedance (P < 0.001) or deuterium dilution (P = 0.002). Fat mass measured by DEXA (P < 0.001), skinfold thicknesses (P < 0.001), and waist/hip ratio (P = 0.001) decreased in the first 6 months. Most changes in body composition were complete by 3 months of treatment and maintained to 12 months. Whole-body bone mineral density (BMD) (by DEXA) was unaffected by GH treatment. Self-reported quality of life was considered good before treatment, and beneficial treatment effects were observed for energy, pain, and emotional reaction as assessed by the Nottingham Health Profile. In the initial 6 months, adverse effects were reported by 84% of patients in the GH and 75% in the placebo group, with more symptoms relating to fluid retention in the GH group (48% vs. 30%; P = 0.016). Such symptoms were mild and resolved in 70% of patients despite continued treatment. Resting blood pressure did not change over the initial 6 months. In summary, GH treatment in adults with GH deficiency resulted in 1) prominent increases in serum IGF-I at the doses employed, in some cases to supraphysiological levels; 2) modest decreases in total- and low-density lipoprotein cholesterol, together with substantial reductions in total-body and truncal fat mass consistent with an improved cardiovascular risk profile; 3) substantial increases in lean tissue mass; and 4) modest improvements in perceived quality of life. The excessive IGF-I response and side-effect profile suggests that lower doses of GH may be a required for prolonged GH treatment in adults with severe GH deficiency.

Adult↗
PubMed1994

The use of fluorescence in-situ hybridisation to clarify abnormal Y chromosomes in two infertile men.

OBJECTIVE: To characterise the structurally abnormal Y chromosomes present in two infertile men by means of the molecular technique of fluorescence in-situ hybridisation (FISH). METHODS: Both men were phenotypically normal and had azoospermia. In Case 1 the karyotype with routine cytogenetics was 46,XX; in Case 2 it was complex, with 3 cell lines--45,X/46,X,i(Yp)/46,X,+?del(Y)(q11). We used probes from the Y chromosome and FISH to clarify these karyotypes. RESULTS: In Case 1 a translocation of Y chromosome to the X chromosome was identified with FISH--t(X;Y). In Case 2, an isochromosome of the short arm of the Y chromosome was confirmed in one cell line, and another cell line was shown to contain a small Y chromosome with heterochromatic deletion. These findings explained the underlying pathogenesis in both cases. CONCLUSIONS: Molecular investigation with FISH should become part of the routine investigation of infertile men with an abnormal Y chromosome.

Adult↗
PubMed1994

Breathing and feeling: capnography and the individually meaningful psychological stressor.

This article briefly discusses capnography and the use of individually meaningful psychological stressors (IMPS) to provoke episodes of acute hyperventilation. Guidelines are provided on history taking, and a strategy for using IMPS with ongoing capnographic monitoring is described, together with a proposal for diagnostic criteria. Diagnosis of hyperventilation using IMPS and capnography can help to demonstrate that feelings, breathing, and symptoms are all interlinked, and may help to suggest appropriate targets for therapy.

Carbon Dioxide↗
PubMed1993

Comprehensive rehabilitation of the child with osteogenesis imperfecta.

Children with osteogenesis imperfecta (OI) that results in considerable deformity are often viewed as poor candidates for aggressive physical therapy and rehabilitation. To determine if this view is realistic, we have entered almost 50 children with OI type III and OI type IV into a comprehensive graduated rehabilitation program, based at the National Institutes of Health, but designed to be implemented by continuing involvement of community resources. Children are begun in the program early with emphasis on gain of head and trunk control and progression to sitting and walking, if possible, with the aid of a variety of physical supports, including internal and external bracing. Although not conducted in a randomized fashion, the program's success in bringing children into graded exercise regimes and fostering their increased involvement in school and social situations suggest that aggressive physical therapy and rehabilitation have a major place in the overall care of the infants and children with OI.

Child↗
PubMed1993

Difficulties in managing a case of stupor.

Stupor is a rare and dramatic presentation of a number of neurological and psychiatric conditions which can cause problems in both diagnosis and management. A case is described which illustrates these difficulties.

Adult↗
PubMed1993

Rehabilitation approaches to children with osteogenesis imperfecta: a ten-year experience.

Twenty-five children with severe osteogenesis imperfecta were followed and treated with physical and occupational therapy for a mean of five years, two months, 80% since the first two years of life. According to their highest achieved motor skill, they fell into three groups: (A) able to stand in braces, (B) able to ambulate short distances without braces, and (C) able to ambulate in the community without assistance. Preventable functional impairment is caused in group A by shoulder joint and hand contractures and upper extremity weakness, group by hip flexion and plantar flexion contractures of the feet, shoulder joint contractures, and upper extremity weakness, and group C by poor lower extremity joint alignment, impaired balance, and low endurance. Appropriate rehabilitation strategies have led to slow, continued functional improvement in the majority of patients. Results of the ten-year retrospective study suggest that clinical groupings based in part on functional needs will enable the clinician to provide optimal rehabilitation services.

Braces↗
PubMed1992

Clinical trials.

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Clinical Trials as Topic↗