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Biomedical subjects

D Simpson

Publications and source records attributed to D Simpson.

At least 253 records · Page 14Linked to original sources
PubMed1983

Depression and antidepressants and the elderly.

Depression is the most common emotional disorder of the elderly. The frequency of grief reaction and the confusion with dementia, hypochondriasis, and sleep disorders complicate both the diagnosis and treatment of depression in older patients. Further, these patients often take medications that can produce or aggravate depression. The choice of antidepressant is based largely on side effects. After evaluating the risk factors, the physician can select a drug on the basis of sedative, anticholinergic, or other side effects. Prior history of response to a particular drug and the physician's experience with particular drugs weight heavily in this decision. Lower initial doses of all medications should be used in the elderly, and dosage should be increased slowly, if possible. These guidelines, derived from clinical experience with tricyclic antidepressants, are presented as a foundation for selecting from the large number of "second generation" antidepressant drugs soon to be available.

Aged↗
PubMed1983

Psychomotor effects of diazepam in anxious patients and healthy volunteers.

Psychomotor effects of diazepam, 5 and 10 mg, were compared to placebo in 30 highly anxious, nonpsychotic outpatients and age and sex-matched healthy volunteers. Diazepam did not reduce anxiety according to psychiatrists' ratings, but 10 mg of diazepam three times a day reduced the scores of the self-rated visual analogue scale for anxiety compared to placebo. Diazepam, 5 mg, was devoid of adverse psychomotor effects, but diazepam, 10 mg, impaired tracking and divided attention task performance in patients and volunteers alike. Plasma, erythrocyte, and saliva diazepam and N-desmethyldiazepam concentrations did not correlate with the impairment of psychomotor skills over time.

Adult↗
PubMed1982

Glutamine distribution in mitochondria from normal and acidotic rat kidneys.

Mitochondria from control and acidotic rat renal cortex were incubated with labeled compounds to determine the distribution of L-glutamine. The mitochondrial preparations lacked detectable phosphate-independent glutaminase activity. In control mitochondria, the distribution of glutamine exceeded that of mannitol by 8% without an added energy source in the medium and by 9.9% when tetramethyl-p-phenylenediamine (TMPD) and ascorbate were present. The distribution of D-ribose (MW 150) was similar to that of L-glutamine (MW 146), indicating that these molecules penetrate into a slightly larger space than D-mannitol (MW 182). Inhibition of phosphate-dependent glutaminase activity with 5 mM glutamate did not alter the volume of glutamine distribution. In mitochondria from chronically acidotic rats, the glutamine/mannitol ratio was 1.03 in the absence of an energy source. With an energy source this ratio fell to 0.88 due to metabolism of glutamine during the separation process. Inhibition of glutamine metabolism with glutamate or alpha-ketoglutarate resulted in distribution ratios of 1.07 and 0.97, respectively. It is concluded that, although glutamine/mannitol ratios greater than 1.00 can be demonstrated in rat kidney mitochondria, such a finding may arise from causes other than the presence of free glutamine in the matrix space. Thus, it has yet to be established whether the inner membrane carrier for glutamine releases glutamine or glutamate into the matrix space.

Acidosis, Renal Tubular↗
PubMed1981

Ethanol and menstrual cycle interactions in the visual evoked response.

Right and left hemisphere visual evoked responses from central locations were collected from 10 normal right-handed women in the follicular and luteal phases of their menstrual cycle. Subjects were tested sober and under 3 doses of ethanol. Amplitude and latency characteristics of the N120 and P180 components for each hemisphere were determined. Asymmetry between hemispheres for the various measurements was then calculated. The follicular phase was associated with a significant P180 latency asymmetry under baseline or placebo conditions. Virtually no asymmetry for P180 latency was present in the luteal phase. Ethanol eliminated the follicular P180 latency asymmetry and reduced the amplitude of both N120 and P180 in a dose-related fashion. The latency of the N120 component was prolonged by ethanol in a similar fashion. Interactions between menstrual cycle and ethanol occurred for both amplitude and latency of P180, but only for the response from the left hemisphere. These occurred at low or moderate doses of ethanol and illustrate the need to consider both the biphasic effects of low doses of ethanol and the possibility of lateralization of these effects to one cerebral hemisphere.

Adult↗
PubMed1981

Scaphocephaly: aesthetic and psychosocial considerations.

A series of 48 children with scaphocephaly has been reviewed. 44 had synostosis of the sagittal suture alone, and four had additional involvement of other sutures. Although six children showed significant developmental delay, with eventual mental retardation in five cases, it does not appear that this is caused by mechanical constriction of the brain. In the majority of cases, scaphocephaly appears to be a benign variant in cranial development. Operation by linear craniectomy was performed for cosmetic reasons in 14 cases, and in general the results were good. Operation was not performed in the other 34 cases, including 15 seen in infancy, and review of these has shown a high incidence of anxiety among parents and children. Therefore there is an acceptable case for cosmetic correction of severe scaphocephaly in infancy.

Adolescent↗
PubMed1980

Comparison of the effects of transcortical and transcallosal removal of intraventricular tumours.

Intelligence and memory functions were tested in 2 patients in whom the corpus callosum had been partially sectioned to remove intraventricular cysts or tumours and in 2 patients in whom similarly-located cysts or tumours had been removed transcortically. A patient with congenital absence of the corpus callosum was also tested. Callosal lesions per se did not appear to be responsible for memory deficits.

Adult↗
PubMed1980

Synthesis, stability, and cleavage of Newcastle disease virus glycoproteins in the absence of glycosylation.

Polypeptides synthesized in Newcastle disease virus (NDV)-infected CHO cells in the absence of glycosylation were characterized. Incorporation of either [3H]mannose of [3H]glucosamine into NDV polypeptides was inhibited to greater than 99% by the antibiotic tunicamycin. Under these conditions, infected cells synthesized proteins which comigrated on polyacrylamide gels with the viral L protein, nucleocapsid protein, membrane protein, and a polypeptide with a molecular weight of 55,000 (P55). These cells did not synthesize polypeptides with the size of the hemagglutinin-neuraminidase (HN) protein or the fusion (F0) protein. They did, however, synthesize new polypeptides with molecular weights of 75,000 (P75), 67,000 (P67), and 52,000 (P52). Peptide analysis revealed that P75 was a host cell protein whose synthesis is enhanced by tunicamycin. P67 corresponded to the unglycosylated forms of the glycoproteins were found to be relatively stable in infected cells. P55, previously thought to correspond to the cleaved form of F0, was found to be a unique viral protein which is associated with intracellular nucleocapsid structures.

Animals↗
PubMed1980

Units for reporting the results of toxicological measurements.

A survey of hospital laboratories and current literature revealed that there is a considerable diversity of units employed for reporting the results of toxicological assays. Consideration is given to some of the problems and difficulties that arise from the use of SI units for reporting drug analyses, resulting from a lack of uniformity.

Humans↗