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Biomedical subjects

J Gilbert

Publications and source records attributed to J Gilbert.

At least 37 records · Page 2Linked to original sources
PubMed1991

Endoscopic thoracic sympathectomy: evaluation of pulsatile laser, non-pulsatile laser, and radiofrequency-generated thermocoagulation.

We describe a modified technique for percutaneous denervation of the thoracic sympathetic chain by laser to treat selected cases of sympathetic causalgia of the upper extremities. The technique involves transpleural ablation with laser under thoracoscopic guidance through the second or third intercostal space-anterior axillary line. We also compare four different modalities of endoscopic denervation: A xenon chloride excimer laser (308 nm, 35 mJ/pulse, 20 pulses/sec, 2.2 mm catheter tip), CO2 laser (14 W, CW, 2 mm spot size), Nd:YAG laser (88 W, CW, 3 mm spot size), and radiofrequency-generated thermocoagulation (3 W, CW, 2.1 mm catheter tip) by performing bilateral thoracic sympathectomy on 12 mongrel dogs (three dogs each). Criteria analyzed included duration of exposure, power density, total energy output, laser penetration and spread, gross morphology, and scanning electron microscopy (SEM) of the destroyed neural tissue. Total ablation of the inferior segment of the stellate ganglion and the T1-T2 nerve roots by excimer laser required 83 +/1 1 Joules over an exposure period of 118 seconds. Ablation by CO2 and Nd:YAG laser required 153 +/- 13 Joules and 554 +/- 47 Joules delivered over 11 and 6 seconds respectively. In contrast, ablation of the same volume of nerve tissue by RF required 810 +/- 50 Joules over 270 seconds. SEM evaluation revealed that excimer and CO2 laser lesions were narrower in configuration compared to RF and Nd:YAG lesions which showed more lateral spread. The actual depth of penetration per 1 second exposure was similar for Excimer and CO2 (1.5 mm) and RF (1.3 mm), but deeper for Nd:YAG (3 mm).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

The outcome index and system outcome score: a method of quality assurance through outcome analysis in the special care area.

A scoring system intended to assess mortality risk and permit surveillance, evaluation and comparison of medical care was developed in our Surgical Intensive Care Unit. Five simple clinical components were identified and assigned scores according to their statistically validated relationship to mortality and the summation of the component scores resulted in a daily System Outcome Score (SOS). Cluster analysis was used to divide the creation data set of 2,777 patients into suitable groupings of scores to predict mortality and the clustering was confirmed for reproducibility with a validation set of an additional 2,860 patients. Two patient care surveillance techniques were then developed. The first involved the definition of three unfavourable SOS patterns evolving during the course of a patient's admission and detection of one or more of these patterns permits identification of specific patients for whom review of care delivered may be appropriate. The second involves a global assessment of care utilizing the Outcome Index (OI) which relates overall mortality risk in the unit to the actual mortality rate over a given time period. The effectiveness of care can then be compared between different time periods within the one unit or between different units with similar patient mix. A simple menu driven program has been developed for the IBM personal computer and clones that facilitates data storage and retrieval, production of outcome reports and customization of the scoring ranges to meet local standards of performance.

Adolescent↗
PubMed1991

Utility of a rapid lamellar body count in the assessment of fetal maturity.

The authors investigated the use of a recently described method for the rapid determination of the lamellar body count (LBC) as a means of evaluating fetal pulmonary maturity. Results of the rapid LBC were compared, alone and in combination with the foam stability index (FSI), with the results obtained by thin-layer chromatography (TLC). The study used 90 consecutive amniotic fluid specimens from 82 patients. Rank ordering of the data suggested cutoff points of 19,000/microL for the rapid LBC and 46 for the FSI. Statistical analysis indicated that the addition of the LBC improved the sensitivity of the FSI (P less than 0.01 by the McNemar test), although the reverse was not the case (P greater than 0.1). The linearity and reproducibility of the LBC were considered acceptable.

Amniotic Fluid↗
PubMed1991

Immunoenhancing properties and antiviral activity of 7-deazaguanosine in mice.

The nucleotide analog 7-deazaguanosine has not previously been reported to possess biological (antiviral or antitumor) properties in cell culture or in vivo. Up to 10(5) U of interferon per ml was detected in mouse sera 1 to 4 h following oral (200-mg/kg of body weight) and intraperitoneal (50-mg/kg) doses of the compound. 7-Deazaguanosine also caused significant activation of natural killer and phagocytic cells but did not augment T- and B-cell blastogenesis. Intraperitoneal treatments of 50, 100, and 200 mg/kg/day administered 24 and 18 h before virus inoculation were highly protective in mice inoculated with lethal doses of Semliki Forest or San Angelo viruses. Less but still significant survivor increases were evident in treated mice infected with banzi or encephalomyocarditis viruses. In most cases, the degree of antiviral activity was similar to that exhibited by the biological response modifier 7-thia-8-oxoguanosine. 7-Thia-8-oxoguanosine was more potent than 7-deazaguanosine against encephalomyocarditis virus in mice, however. Oral efficacy was achieved with 7-deazaguanosine treatments of greater than or equal to 100 mg/kg against all virus infections, whereas 7-thia-8-oxoguanosine is reported to be devoid of oral activity in rodents. Thus, 7-deazaguanosine represents the first reported orally active nucleoside biological response modifier exhibiting broad-spectrum antiviral activity against particular types of RNA viruses.

Adjuvants, Immunologic↗
PubMed1990

Glycerophosphoethanolamine concentration is elevated in brain of patients with dominantly inherited olivopontocerebellar atrophy.

We measured the concentration of glycerophosphoethanolamine (GPEA), a membrane breakdown product, in autopsied brain of 10 patients with dominantly inherited olivopontocerebellar atrophy (OPCA), a cerebellar ataxia disorder. As compared with the controls, mean GPEA levels were significantly elevated by 37-69% in 11 of the 15 brain areas examined, including extracerebellar brain regions in which no neuronal cell loss could be detected by semiquantitative estimation. Our data suggest the possibility of altered membrane phospholipid metabolism in OPCA which could be a contributing factor in the neuronal cell death.

Adult↗
PubMed1990

Multiple mechanisms of protein kinase C inhibition by triphenylacrylonitrile antiestrogens.

The activation of type I (gamma), II (beta) and III (alpha) protein kinase C (PKC) subspecies by phosphatidylserine (PS) and diacylglycerol (DAG) is inhibited by micromolar concentrations of triphenylacrylonitrile (TPE) antiestrogens. TPE A (with p-hydroxy and p-diethylaminoethoxy groups on the 3- and 3'-phenyl rings, respectively) interacts with PS-vesicles as well as with the regulatory domain of PKC, probably at a site different from the Ca2+ and DAG binding sites. The interaction of TPE A with the regulatory domain of enzyme is very slow. Apparently, TPE A does not interact with the catalytic domain of PKC. In contrast, another TPE derivative, TPE B (with a p-hydroxy group on each of the three phenyl rings) inhibits the enzyme activity in a competitive manner with respect to ATP, suggesting that this TPE interacts with the catalytically active site of the enzyme. It seems likely that various TPE antiestrogen derivatives may exert their inhibitory action on PKC by multiple different mechanisms.

Acrylonitrile↗
PubMed1990

Hydroxylated triphenylacrylonitriles adopt a unique orientation within the binding site of the estrogen receptor.

The relative binding affinities of a series of twelve para-hydroxylated triphenylethylenes (TPEs) for the estradiol receptor (ER) of calf uterus cytosol were measured by a competition method. The results obtained under equilibrium conditions support the hypothesis of the additivity of the energies corresponding to each of the hydrogen-bond type interactions of di- or tri-hydroxylated TPEs with the estradiol binding site of ER and strongly suggest that, whichever ring is hydroxylated, the orientation of the TPE in the steroid binding site is always the same. A hydroxyl group in a given position always interacts with the same location within the site. Mono-hydroxylation of the highly hydrophobic non-substituted TPE skeleton led to a large increase in relative binding affinity for ER which could be explained by a dual mechanism whereby the interaction specific to the hydroxyl is accompanied by a temperature- or time-dependent binding process that is not related to the hydroxylation position.

Animals↗
PubMed1990

Evaluation of an inactivated rabies virus vaccine in domestic ferrets.

Efficacy of an SC-administered commercial inactivated vaccine for prevention of rabies was evaluated in domestic ferrets. Ferret immunity was challenged by the IM inoculation of street rabies virus. All ferrets developed titers of rabies virus-neutralizing antibodies within 30 days of vaccination (geometric mean titer [GMT] = 154, n = 41) that were maintained for at least one year (GMT = 106, n = 36), compared with no seroconversion in controls (GMT less than 5, n = 39). Following rabies virus challenge inoculation, 89% (32/36) of vaccinated ferrets survived vs less than 6% (2/38) survival in control ferrets. These results demonstrate the protective efficacy of a commercial, inactivated rabies vaccine of at least one year's duration for domestic ferrets.

Animals↗
PubMed1990

Dual action of hydroxylated diphenylethylene estrogens on protein kinase C1.

Protein kinase C (PKC) I (gamma), II (beta) and III (alpha) subspecies are all activated by 1,1-di-(p-hydroxyphenyl)ethylene derivatives (DPE) at micromolar concentrations. This PKC activation depends on the presence of both Ca2+ and phosphatidylserine (PS) but does not require diacylglycerol (DG). DPEs enhance PKC activity at low PS concentrations, but not at saturating PS concentrations. Like DG, DPEs increase the apparent affinity of PKC for PS as well as for Ca2+, but lead to a decrease in the catalytic activity (Vmax). In the presence of saturating DG concentrations, DPEs exhibit an inhibitory action. The derivatives also inhibit the activity of the proteolytic fragment of PKC, protein kinase M. It is concluded that DPEs are mixed-type inhibitors, probably interacting with the catalytic domain of the enzyme.

Animals↗
PubMed1990

Penile agenesis: a fatal variation of an uncommon lesion.

Two male neonates (46XY karyotype) were born with a triad of penile agenesis associated with imperforate anus and complete absence of the median raphe. Both patients died of renal dysplasia and secondary pulmonary hypoplasia shortly after birth. This triad appears to be secondary to a lack of caudal mesoderm migration during month 1 of gestation, leading to severe developmental defects in the caudal axis. In all reported cases to date this triad of findings has been incompatible with extrauterine life.

Abnormalities, Multiple↗
PubMed1990

Modified system outcome score and outcome index--method of monitoring patient care in a special care area.

A scoring system intended both to assess mortality risk and permit surveillance, evaluation, and comparison of medical care was developed in our surgical ICU. Five simple clinical indices of organ system failure were selected and weighted according to their statistically validated relationship to mortality, resulting in a daily System Outcome Score (SOS). Cluster analysis was used to divide the creation data set of 2,777 patients into suitable groupings of scores to predict mortality; the clustering was confirmed for reproducibility with a validation set of an additional 2,860 patients. Based on this validation of the scoring system, two computer-controlled patient care surveillance techniques were developed. The first involved the definition of three unfavorable SOS patterns evolving during the course of a patient's admission. Detection of one or more of these patterns, described by the acronym SDL, permits review of the care administered to the specific patient generating the pattern. A global assessment of care is achieved with the Outcome Index (OI), which relates overall mortality risk in the ICU to the actual mortality rate over a given time period. Effectiveness of care can then be compared between different time periods within the one unit or between different units with similar patient mix. The overall system offers the potential for a surveillance-based quality assurance system with widespread applicability.

Hospital Information Systems↗
PubMed1990

Clinical monitoring of steatorrhoea in cystic fibrosis.

In 100 patients with cystic fibrosis the severity of steatorrhoea was assessed by three separate methods. Using chemical faecal fat assay as the gold standard, two other rapid and inexpensive methods were compared with it. The steatocrit method proved unreliable in our hands and gave little indication of the presence or severity of steatorrhoea. The more simple microscopy method was highly sensitive (97%) and only three of 80 patients with steatorrhoea were missed. All patients with severe steatorrhoea (greater than 60 mmol fat/day) were clearly demonstrated. The method is applicable to spot faecal samples and can readily be carried out on an outpatient basis. In centres where faecal fat assays are not available, the simple and cheap microscopic examination will give some indication of the response to enzyme treatment and may also help to identify non-compliant individuals.

Adolescent↗
PubMed1990

Brain neurotransmitter changes in three patients who had a fatal hyperthermia syndrome.

The authors examined the autopsied brains from three patients who had a fatal hyperthermia syndrome. There was marked hypothalamic noradrenaline depletion in all three patients, severe brain choline acetyltransferase deficiency with nucleus basalis cell loss in two patients, and mild to moderate brain choline acetyltransferase loss in one patient. Striatal dopamine metabolite/dopamine ratio was below normal in two patients and not elevated, as would be expected after short-term neuroleptic administration, in the third. This suggests that reduced capability (aggravated by the cholinergic deficit) of the nigrostriatal dopamine system to respond adequately to stress and/or neuroleptic-induced receptor blockade may be important in the development and course of fatal hyperthermia syndrome.

Adolescent↗
PubMed1990

Fourth ventricular schwannoma. Case report.

A schwannoma arising from the dorsum of the pontomedullary junction and presenting as an exophytic mass in the fourth ventricle is described. A ventricular schwannoma has not previously been reported in the literature. The presenting clinical and radiographic features and the pathology of this tumor are summarized, and an explanation is sought for its unusual location.

Brain Neoplasms↗