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Biomedical subjects

J Gilbert

Publications and source records attributed to J Gilbert.

At least 181 records · Page 10Linked to original sources
PubMed1984

Influence of new hydroxylated triphenylethylene (TPE) derivatives on estradiol binding to uterine cytosol.

Twelve homologous triphenyl acrylonitrile derivatives with a p-OH or p-CH3 group on one or more of the phenyl rings were synthesized in order to assess the relative influence of each position on binding to the estrogen receptor (ER) and on inhibition of prostaglandin synthetase (PGS). Their relative binding affinities (RBAs) for [3H]estradiol (E2)-labeled ER were compared at 0 and 25 degrees C in mouse and rat uterus cytosol with those of tamoxifen derivatives, cyclofenil and diethylstilbestrol. RBAs in both species were closely correlated (r = 0.92) although the RBAs were about twice as high in the mouse as in the rat. The unsubstituted skeleton had an RBA of much less than 0.1 (estradiol = 100). An OH-group in R1 or R2 (Fig. 1) engendered very low affinity whereas an OH-group in R gave rise to a compound with an RBA equivalent to that of E2, emphasizing the importance of this position in the interaction with ER. Compounds with an additional OH-group in R1 or R2 were significantly better competitors than E2. No further increase in RBA was noted with the trihydroxy derivative. The effect of the introduction of a hydrophobic CH3-group decreased affinity as expected in R, but also in position R1 unless a second OH-group was present in R2. None of the 12 test-compounds competed significantly for binding to the "anti-estrogen binding site" in rat kidney supernatant. Although polar groups were not necessary for inhibition of PGS, inhibition was enhanced by the presence of a hydroxy group in R or R1 (but not R2). Even greater inhibition was obtained by the further introduction of a CH3-group in R1 or R respectively. The conformations of these derivatives are compared to those of known estrogen ligands and anti-inflammatory agents in order to obtain further information on these protein recognition sites.

Acrylonitrile↗
PubMed1984

The effect of various acrylonitriles and related compounds on prostaglandin biosynthesis.

We have studied the effect of nearly 90 arylacrylonitrile derivatives, and several related compounds, on the biosynthesis of prostaglandins from bovine seminal vesicle microsomes. This effect was compared to that of triarylacrylonitrile derivatives known for their inhibiting properties. Several arylacrylonitrile derivatives have also proved good inhibitors, especially certain N-trisubstituted compounds: trans (dimethylamino-4 phenyl)-3 (methoxy-4' phenyl)-2 acrylonitrile was the best inhibitor of the group, with an IC50 of 0.07 microM. The absence of carboxy groups in these derivatives precludes the application of any of the site-models proposed to date. We suggest that the electronic charges carried especially by the three aromatic rings play an important role in the inhibiting mechanism.

Acrylonitrile↗
PubMed1984

Life-style intervention: a conceptual framework.

Improving one's life-style may improve one's health. However, there is a lack of consensus on how to promote compliance with newly adopted health habits. This paper presents a conceptual framework that individuals can learn to assess their life-styles and plan for health-behavior changes. It can also be used by professionals from different disciplines who are developing programs to teach healthy life-style choices. The framework is organized into three ideas: (1) Health status to a large extent reflects the individual's styles of living (a composite of beliefs, emotions, and action patterns). (2) These styles can be encouraged or sabotaged by the individual's support structures (relationships, environments, and equipment). (3) The change process can be seen as a series of steps that cycle through phases of readiness appraisal, decision making, experimentation, and reevaluation. clinical examples and documentation from relevant theory and research illustrate and substantiate the framework.

Health Status↗
PubMed1984

Continuous flow apneic ventilation.

A study was designed to evaluate the adequacy of gas exchange during continuous flow apneic ventilation (CFAV) in dogs. Seventeen dogs (average weight 22.9 kg) were divided into three experimental groups. Group I (n = 7) was anesthetized, paralyzed and ventilated with air using intermittent positive pressure ventilation (IPPV) through a tracheal tube. The tube was removed and each main stem bronchus was cannulated with a 2.5 mm i.d., 4 mm o.d. polyethylene catheter using a fiberoptic bronchoscope. The tracheal tube was replaced to hold the catheters in place. Heated, humidified air was continuously delivered equally to each catheter. Total flows ranged from 8 to 28 l/min (0.4-1.4 l X kg-1 X min-1). Airway pressure (Paw) in the trachea did not exceed 2 mmHg (0.27 kPa). Adequate gas exchange in terms of arterial oxygen and arterial carbon dioxide tension (Pao2 and Paco2) was found after 30 min at flows greater than 16 l X min-1. Group II (n = 7) was managed similarly to the first group, insufflating endobronchial air using the optimal flow of 1.0 l X kg-1 X min-1 obtained from Group I. CFAV continued for 5 h in all animals. Blood gas samples and measurements of systemic blood pressure, heart rate (HR), pulmonary artery blood pressure, pulmonary artery wedge pressure, cardiac output (Qt), and temperature were taken every 30 min. Group III (n = 3) was anesthetized similarly to the other groups. Pulmonary gas distribution was evaluated in relation to catheter placement using Xe133. Results showed significant differences between Pao2 values during CFAV and IPPV; however, all animals were adequately oxygenated.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMed1983

Deliberate metallic paint inhalation and cultural marginality: paint sniffing among acculturating central California youth.

Deliberate metallic paint inhalation, paint sniffing, has recently become the focus of community concern in central California, as numbers of recalcitrant young abusers have entered the overloaded Mental Health and Juvenile Justice systems. This study, based on an extension of psychological, sociological and anthropological explanations of inhalant abuse, describes the adolescent paint sniffer and proposes that a combination of interacting factors both differentiates him/her from other-drug abusing youth, and predisposes him/her to inhalant use. The experimental hypothesis was tested by a stepwise discriminant analysis performed on 50 subjects, equally divided into two groups, paint and other-drug. Six variables, in combination, were found to significantly differentiate the groups, and the derived function accounted for 56% of the between group differences. The following conclusions can be drawn from this investigation. Firstly, the adolescent paint sniffer is demonstrably and meaningfully different as discriminated by a combination of personal, familial and sociocultural variables. Secondly, these identified factors have predisposed the sniffer to abuse, and cannot be considered simply the consequence of said abuse. Finally, it can be concluded that the paint sniffer is a youth disengaged from the symbols and traditions of his/her culture of origin and concomitantly rejected by the majority culture. Inhalant intoxication provides a "cheap" and effective escape from his/her isolation. Recommendations for prevention, early intervention and treatment are addressed.

Acculturation↗
PubMed1983

Inhibition of prostaglandin synthetase by di- and triphenylethylene derivatives: a structure-activity study.

The syntheses of new di- and triphenylethylene derivatives are described along with their X-ray analysis and NMR study, which have helped to establish their conformation. Screening of over 50 derivatives for inhibition of prostaglandin synthetase (PGS) activity in bovine seminal vesicle microsomes has revealed that many of the triphenylethylene derivatives are potent inhibitors of PGS. Several even show marked activity at the extremely low concentration (IC50) of about 4 X 10(-8) M, which is two orders of magnitude lower than the active concentration of the majority of known nonsteroidal antiinflammatory agents (IC50 approximately equal to 10(-6) M). Unlike the latter, these compounds are not carboxylic acids. Furthermore, in contrast to biphenyl, diphenylmethane, or unsymmetrical, alpha, alpha'-diphenylethylene PGS inhibitors, the presence of a beta-phenyl ring was an essential requirement for high potency. The best inhibitors possessed a cyanide group (acids, amides, and amines were poor inhibitors), methoxy in preference to hydroxy groups on the alpha-phenyl rings, and a halogen (F or Cl) in a para position on the beta-phenyl ring. These data provide additional insight into the nature of the PGS binding site.

Animals↗
PubMed1982

The action of aldosterone and ouabain on cation concentrations in incubated renal slices.

Studies have been made on the effects of aldosterone and ouabain on Na+ and K+ concentrations in incubated rat kidney slices. The results indicate that, control slices gained Na+ over the first 10 min of incubation and subsequently extruded it, with increase in incubation time. In the presence of aldosterone, the same pattern was observed as with control slices, but tissue Na+ concentrations were significantly higher at all times. In the presence of ouabain, slices accumulated Na+ continuously, but in the presence of both drugs, tissue Na+ concentrations were not as high as with ouabain alone. Both aldosterone and ouabain increased the loss of cell K+ whereas control slices reaccumulated their intracellular K+ concentration, with increase in incubation time. The results suggest that aldosterone may have an actual mechanism of action in the renal tubule: either by activating two Na+, K+ pumps located on the luminal and serosal membranes, respectively, or by enhancing luminal membrane permeability, and at the same time stimulating Na+, K+-ATPase on the serosal membrane.

Aldosterone↗
PubMed1982

[Factor analysis of the structure-activity relationship of di- and triphenylethylenes in 2 biochemical tests].

This paper deals with the study of biochemical activity, by means of correspondence analysis, of about fifty original molecules of di- and triphenylethylene structures. The pharmacological experiments were made on glutamate deshydrogenase and prostaglandine synthetase. A typology of several molecular groups is established and the effects of various substituents are specified.

Animals↗