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Biomedical subjects

R Gilbert

Publications and source records attributed to R Gilbert.

At least 55 records · Page 3Linked to original sources
PubMed1985

The interpretation of the spirogram. How accurate is it for 'obstruction'?

The accuracy of the spirogram in detecting or excluding airway obstruction based on airflow limitation was assessed prospectively in 200 subjects, 74 with obstruction and 126 without it. The diagnosis of airway obstruction was based on a combination of clinical and body plethysmographic data. The ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC %) had a sensitivity of 0.82 and a specificity of 0.98. A fixed lower limit seemed better than a lower limit based on prediction formulas. Because specificity is so much higher than sensitivity, less precise clinical information is required to confirm the presence of obstruction if FEV1/FVC % is abnormal than is needed to exclude obstruction if FEV1/FVC % is normal. Using a combination of FEV1/FVC % and the ratio of forced expiratory flow (FEF) at 50% of FVC gave a higher sensitivity with a comparable specificity when compared with FEV1/FVC % used alone. A normal value for FEF between 25% and 75% of FVC virtually ruled out obstruction, but low values had poor specificity.

Adult↗
PubMed1984

Patterns of alliances in nondistressed and multiproblem families.

The goal of this study was empirically to investigate differences between distressed and nondistressed families in the strength, patterning, and cross-situational consistency of alliances. Audiotapes were made of 12 distressed and 12 nondistressed families in two observational situations. The resultant interaction was then coded for family alliances by trained observers. Distressed families were characterized by low overall levels of alliance behavior, weakness in the marital alliance relative to other family alliances, and discrepancies in parental alliances with the target child. There were generally no differences between groups in the cross-situational variability of alliance strength or patterning. The results are discussed in relation to the predictions of structural models of family process.

Adolescent↗
PubMed1984

Hyperactive children: a study of the content analysis of their speech.

A group of hyperactive boys with attention deficit disorder (DSM-III) (n = 13) was compared to a group of normative, nonhyperactive boys (n = 16) with respect to Gottschalk-Gleser scores derived from 5-min speech samples they produced in response to standardized and purposely ambiguous instructions. The hyperactive boys had significantly higher mean scores than the normative boys for cognitive impairment, social alienation-personal disorganization, and total depression. Of the eight depression subscales, the hyperactive boys had significantly elevated scores on hopelessness, self-accusation (a cluster composed of shame, guilt, and hostility inwards), and psychomotor retardation. Problems with the classification of the hyperactive syndrome, which is equated with the attention deficit disorder, are briefly discussed. The present study gives some support to the concept, as adjudged from the content analysis of verbal behavior, that hyperactivity, at least in boys, may be associated with cognitive impairment, increased general psychiatric morbidity, and depression. Whether single or multiple etiological factors are involved in this disorder cannot be ascertained from this study.

Attention Deficit Disorder with Hyperactivity↗
PubMed1984

Pharmacologic identification, activation and antagonism of two muscarine receptor subtypes in the lower esophageal sphincter.

Lower esophageal sphincter pressures were monitored with water-filled catheters in anesthetized opossums. Muscarinic agonists McN-A-343 and bethanechol were administered in the arterial supply of the sphincter. McN-A-343 caused relaxation after a brief contraction of the sphincter. Bethanechol caused a dose-dependent contraction. Tetrodotoxin antagonized the inhibitory effect of McN-A-343 but did not antagonized sphincter contraction caused by McN-A-343 or bethanechol. The mean ED50 values were 6.9 nmol/kg i.a. for McN-A-343-induced relaxation, 10.5 nmol/kg i.a. for McN-A-343-induced contraction and 0.4 nmol/kg i.a. for bethanechol-induced contraction. Atropine caused a dose-dependent rightward shift in the dose-response curves of inhibitory and excitatory effects of the two muscarinic agonists. Pirenzepine caused a dose-dependent rightward shift in the dose-response curves of McN-A-343-induced relaxation. Pirenzepine did not modify sphincter contraction caused by the muscarinic agonists. 4-Diphenylacetoxy-N-methylpiperidine methiodide, on the other hand, did not modify McN-A-343-induced sphincter relaxation but caused dose-dependent rightward shifts in the dose-response curves of sphincter contraction caused by McN-A-343 or bethanechol. These studies suggest that there are two distinct types of muscarine receptors in the opossum lower esophageal sphincter. The M1 muscarine receptors are present on the inhibitory neurons and participate in the synaptic transmission between vagal preganglionic and intramural postganglionic inhibitory neurons. They are activated by McN-A-343 and antagonized by pirenzepine. The M2 muscarine receptors are located directly on the sphincter muscle. They are also activated by McN-A-343, but are selectively activated by bethanechol and are antagonized by 4-diphenylacetoxy-N-methylpiperidine methiodide.

(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethy↗
PubMed1982

The presence of a receptor for complement on T lymphocytes. Restriction of the complement receptor to Fc-receptor-bearing T lymphocytes.

Using rhodaminated guinea pig anti-ovalbumin:ovalbumin:complement complexes, a fluoresceinated monoclonal anti-Thy 1 antibody and a FACS-II equipped with dual fluorescence detection channels, we find that 25-30% of Thy 1+ splenocytes express a receptor for complement. That a receptor for complement is involved in binding the guinea-pig AgAb:C' complexes is supported by the observations that: a) guinea-pig complexes, which were not treated with a serum source of complement or which were treated with either fresh serum in the presence of EDTA or with heat-inactivated serum, do not bind to the T lymphocytes, and b) heat-aggregated human gamma globulin, which effectively inhibits binding of mouse AgAb complexes to the aFcR gamma, has no effect on the binding of guinea-pig AgAb:C' complexes to the T lymphocytes. By analyzing cell subpopulations isolated by cell sorting, it is demonstrated that the C'R-positive T lymphocyte clearly delineates a major subpopulation of aFcR gamma-positive T lymphocytes, whereas no cells are found bearing a C'R, while lacking the aFcR gamma. The implications of the presence of a C'R in immunoregulation are discussed.

Animals↗
PubMed1982

Correlation of amylase and lecithin sphingomyelin ratios in amniotic fluid samples.

The use of amniotic fluid amylase (AF amylase) has been proposed as a screening test to determine fetal maturity. We reviewed data from 944 amniotic fluid samples analyzed by our laboratory for amylase and lecithin sphingomyelin (L/S) ratio between 1975 and 1980. AF amylase shows poor overall correlation with L/S ratios (r = 0.256). Retrospective analysis of AF amylase as a screen to determine the need for L/S ratios showed an overall sensitivity of 57%, and an overall specificity of 86% for AF amylase. Three groups were studied: a low amylase group (amylase less than 200 U/L), a middle group (amylase 200-300 U/L), and a high amylase group (amylase greater than 300 U/L). Only 55% of the low amylase group had an immature L/S ratio. The high amylase group had the best correlation between AF amylase and L/S ratio, but 13% of these samples had an immature or borderline L/S ratio. We conclude that AF amylase cannot be used as a screening test to determine the need to perform L/S ratios.

Amniotic Fluid↗
PubMed1981

Presence of avian pancreatic polypeptide-like immunoreactivity in catecholamine and methionine-enkephalin-containing neurones within the central nervous system.

Using single and double staining immunohistochemical procedures it has been demonstrated that an avian pancreatic polypeptide-like immunoreactivity (APP-LI) co-exists with catecholamines in neurones within the A1/A3, A2 and A6 (locus coeruleus) cell groups, and also with methionine-enkephalin in cell bodies of the sacral parasympathetic system. Axonal and terminal immunoreactivity was observed in axons and nerve terminals in particularly high density within the dorsal horn of the spinal cord and originated in part from intrinsic cell bodies. Intense terminal labelling was also found around sacral and caudal lumbar motor neurones, and thoracic lateral sympathetic column neurones. Immunoreactive material was present in fibres around neurones of the periaqueductal grey, caudal raphe and the locus coeruleus and in neurones in the arcuate nucleus.

Animals↗
PubMed1981

Relationship of rib cage and abdomen motion to diaphragm function during quiet breathing.

Although rib cage (RC) and abdomen (Ab) motion is believed to reflect intercostal and diaphragm contributions to breathing, systematic investigations have failed to confirm this. We measured inspiratory changes in RC and Ab anterior-posterior diameter (delta RC and delta Ab) both corrected for volume equivalence (isovolume) and not corrected (isodistance, observed), and correlated these with simultaneous changes in gastric (delta Pab) and esophageal (delta Ppl) pressure: delta Pab - delta Ppl = delta Pdi, the change in transdiaphragmatic pressure. The delta Pab/delta Pdi was used as an index of the relative contribution of diaphragm motion to the breathing process. Relative abdomen motion was expressed as delta Ab/(delta Ab + delta RC). Isodistance and isovolume delta Ab/(delta Ab + delta RC) correlated, R = 0.69; observed abdomen motion overestimated abdomen-diaphragm contribution to tidal volume. Isodistance delta Ab/(delta Ab + delta RC) was less for women than men; isovolume delta Ab/(delta Ab + delta RC) was similar for the two sexes. Among individuals, isodistance delta Ab/(delta Ab + delta RC) correlated with delta Pab/delta Pdi (R = 0.73, P less than 0.001). Within a given individual, the mean R for seven subjects for delta Pab/delta Pdi vs delta Ab/(delta Ab + delta RC) was 0.90. We conclude that observed rib cage and abdomen motion reflects intercostal and diaphragm contributions to breathing; the correlation is better within a given subject than among individuals.

Abdomen↗
PubMed1980

One minute oxygen uptake in peripheral ischemic vascular disease.

Six males, ages 31-58, with ischemic vascular disease of the lower extremities, underwent treadmill testing with measurement of oxygen uptake at 45-60 seconds of exercise (VO2-45-60) as the test score. Tests were performed at 41, 123 and 164 watts of power against gravity. Depressed values were found in five subjects with aortic, iliac or common femoral disease but normal values in a subject with narrowing of the left superficial femoral artery. Reconstructive surgery resulted in normal values in four subjects retested. In three of these a calculation was made of the increased volume of oxygen uptake during the first minute of exercise associated with postsurgical improvement. The average was 430 ml, a value high enough to suggest increased aerobic metabolism of exercising muscles.

Adult↗
PubMed1980

Characterization of corticosterone-induced protein synthesis in hippocampal slices.

Corticosterone significantly increases the incorporation of [3H]leucine into specific cytosol protein(s) isolated from in vitro hippocampal slices prepared from adult male albino rats. The present study showed that in slices coincubated with glucocorticoid plus a protein synthesis inhibitor (1 mM-cycloheximide), no such enhancement of amino acid incorporation was observed, suggesting that the hormone acts in the hippocampus to increase de novo protein synthesis. Further experiments demonstrated that the steroid-induced protein synthesis was first detectable (+ 5.7%) following a 30-min exposure of slices to corticosterone; slices incubated for 1 or 2 h both showed a 12% increase in synthesis of the affected protein(s) when compared with controls. In an attempt to determine whether the glucocorticoid alteration of protein metabolism was receptor-mediated, hippocampal slices were also incubated with 10 nM-progesterone, a steroid known to compete for corticosterone binding to its cytosol receptor. Progesterone alone, which does not translocate cytoplasmic receptors to the nucleus, did not alter hippocampal protein metabolism and effectively blocked the induction by corticosterone of the 54K protein(s). These studies provide evidence that in the rat hippocampus corticosterone interacts with high-affinity steroid receptors to regulate the synthesis of specific protein(s).

Animals↗
PubMed1980

Mixed venous CO2 tension during exercise.

A series of experiments was undertaken in a total of 95 adult subjects, of whom 25 had coronary artery disease, to evaluate the extrapolation (Defares) CO2 rebreathing method vs. the equilibrium (Collier) method for estimating mixed venous CO2 tension. Collier values were corrected for the downstream effect, whereas Defares values were uncorrected. Although the methods gave similar mean values in separate series with normal subjects walking on a treadmill set at 123 W for 3 min, Collier values had a coefficient of variation (CV) of 2.5% in duplicate determinations and Defares values had a CV of 4.5%. In paired comparisons Defares values averaged either higher or lower than Collier values depending on variations in technique and the analysis of Defares tracings. Collier values were essentially unaffected by the duration of the rebreathing period (10 vs. 15 s). The Collier technique appears to be superior for the exercise evaluation of cardiac output in healthy and diseased subjects when the goal is obtain values at 82 or 123 W in single test sessions.

Adult↗
PubMed1979

Stability of the arterial/alveolar oxygen partial pressure ratio. Effects of low ventilation/perfusion regions.

The alveolar-arterial oxygen partial pressure difference (AaDO2) and the arterial/alveolar oxygen partial pressure ratio (a/APO2) were compared for stability when inspired oxygen concentration (FIO2) changed. The analysis was based on a three-compartment lung model and experimental results in 10 patients with respiratory failure receiving assisted ventilation. It was found that a/APO2 was more stable than AaDO2 and more useful for: (1) comparing gas exchange in patients receiving different levels of FIO2, (2) following gas exchange in the same patient as FIO2 is changed, and (3) estimating the PaO2 expected at a given level of FIO2 if blood gas data are available at another level. However, areas with low ventilation/perfusion (V/Q) ratios may cause sudden changes in a/PO2 at certain critical values of PAO2. Most stable is a/APO2 and, therefore, most useful at FIO2 levels greater than 0.3, and PaO2 levels less than 100 torr.

Adult↗