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Biomedical subjects

R Bowen

Publications and source records attributed to R Bowen.

At least 37 records · Page 2Linked to original sources
PubMed1993

Reversible monoamine oxidase-A inhibitors in panic disorder.

Monoamine oxidase (MAO) inhibitors are known to be effective in panic disorder, but a high incidence of adverse reactions have limited their use. The new, selective, and reversible MAO-A inhibitors exemplified by brofaromine and moclobemide do not require dietary restrictions, have fewer drug interactions, and are better tolerated. This paper reports a randomized, double-blind, 8-week trial in which the efficacy and safety of brofaromine was compared to clomipramine in patients with panic disorder with or without agoraphobia. Both treatments achieved a significant and comparable reduction in the number of panic attacks, and were equally effective in all the parameters measured. Side effects were typical of the drug class. Further trials are required to evaluate this promising new treatment.

Agoraphobia↗
PubMed1993

The cardiovascular and intracranial effects of laryngoscopy and endotracheal intubation in hypercarbic neonatal piglets.

Laryngoscopy and endotracheal intubation is a potent sympathetic stimulus in adults. Neonates are frequently intubated, but few data exist on the cerebral effects of this intervention. The cardiovascular and intracranial effects of laryngoscopy and endotracheal intubation were studied in 17 hypercarbic neonatal piglets. The mean arterial pressure in the study group (11 piglets) increased significantly within 2 minutes of the stimulus, and remained elevated for almost 14 minutes. The intubated animals showed significantly more haemorrhage in the basal area of the brain than the 6 control animals. The distribution suggests bleeding in the choroid plexus of the 4th ventricle. The significance of such bleeds is not immediately apparent, since none of the animals was grossly neurologically affected by the intervention. However, subtle long-term neurological deficits cannot be excluded and this aspect requires further study. Laryngoscopy and endotracheal intubation may cause non-lethal haemorrhage in the choroid plexus and central canal of the hindbrain in hypercarbic, neonatal piglets.

Animals↗
PubMed1991

Effects of nitrovasodilators on platelet cyclic nucleotide levels in rabbit blood; role for cyclic AMP in synergistic inhibition of platelet function by SIN-1 and prostaglandin E1.

Nitrovasodilators increase both cyclic GMP and cyclic AMP in isolated platelets (Maurice DH, Haslam RJ. Mol Pharmacol 1990;37:671-81). To determine whether this occurs in blood, platelet cyclic[3H]GMP and cyclic [3H]AMP were measured in prelabeled rabbit platelets resuspended in modified Tyrode's solution or citrated blood. In the former medium, increases in cyclic [3H]nucleotides in response to nitroprusside (NP) and 3-morpholinosydnonimine (SIN-1) were maximal by 1 min; in blood, maximal increases were observed only after 10 min and were much smaller. In blood, SIN-1 was more effective than the same concentration of NP. After 10 min, 100 microM SIN-1 increased platelet cyclic[3H )GMP by 475 +/- 58% and cyclic[3H]AMP by 29 +/- 7% (means +/- SEM, 18 experiments). Supraadditive increases in platelet cyclic [3H]AMP in blood were observed when SIN-1 was combined with prostaglandin E1 (PGE1). Thus, after 10 min, SIN-1 (100 microM), PGE1 (20 nM), and SIN-1 + PGE1 increased cyclic[3H]AMP by 25 +/- 7, 35 +/- 6, and 130 +/- 17%, respectively (four experiments). In the same experiments, release of platelet [14C]serotonin by platelet-activating factor (PAF) was inhibited by 22 +/- 5, 2 +/- 2, and 61 +/- 5%, respectively. Increases in platelet cyclic[3H]GMP with SIN-1 were unaffected by PGE1. These results suggest that although cyclic GMP may mediate the effects of SIN-1 alone on platelet function, cyclic AMP mediates the synergistic action of SIN-1 and PGE1. M&B 22,948 (a selective cyclic GMP phosphodiesterase inhibitor) enhanced the increases in platelet cyclic[3H]GMP and cyclic[3H]AMP caused by SIN-1 and also increased the associated inhibition of [14C]serotonin release. M&B 22,948 also augmented the synergistic increases in cyclic[3H]AMP and inhibition of platelet function caused by SIN-1 + PGE1. The results show that a selected nitrovasodilator (e.g., SIN-1), a prostaglandin and a cyclic GMP phosphodiesterase inhibitor can exert synergistic effects on platelets in blood. This may be relevant to the pharmacologic management of thromboembolic disease.

Alprostadil↗
PubMed1989

Bivens arm virus: a new rhabdovirus isolated from Culicoides insignis in Florida and related to Tibrogargan virus of Australia.

During field studies in 1981 on the transmission of bluetongue viruses in ruminants in Florida, a virus was isolated from Culicoides insignis collected near water buffalo (Bubalus bubalis) recently imported from Trinidad. Electron microscopy showed that this isolate, for which the name Bivens Arm virus is proposed, has rhabdovirus morphology. Serologic comparisons were made with recognized rhabdoviruses from terrestrial vertebrates and hematophagous arthropods. Indirect fluorescent antibody, complement fixation and neutralization tests indicated antigenic reactivity between Bivens Arm virus and two rhabdoviruses found only in Australia, Tibrogargan and Coastal Plains viruses. The Australian isolates cause subclinical infections in cattle and water buffalo and are believed to be transmitted by Culicoides. Initially, it was thought that Bivens Arm virus may have been introduced to Florida with the water buffalo from Trinidad, but a serologic survey of cattle serum, collected before the importation of the buffalo revealed antibody to the virus in cattle on farms located in diverse areas of Florida.

Animals↗
PubMed1988

Neurocysticercosis: correlative pathomorphology and MR imaging.

CT and MR images of 32 patients with neurocysticercosis were correlated with pathomorphology. Gross morphological features of cystic larvae, complex arachnoid cysts, granulomatous abscesses, basal meningitis and mineralised nodules correlated closely with the images obtained, especially on MR, where resolution permitted visualisation of larval protoscolices. Our material indicates three forms of the natural history of neurocysticercosis related chiefly to anatomic location, and provides details of the evolution of large, complex arachnoid cysts.

Brain↗
PubMed1985

Chylothorax review.

Chylous leakage from the thoracic duct into the pleural space may occur after any type of thoracic surgery; however, there are few reports of this condition after coronary artery bypass grafting. A case of chylothorax after combined coronary bypass and mitral valve replacement is reported to illustrate a discussion of its pathologic basis, diagnosis and management.

Chyle↗
PubMed1984

Amyloidosis at Groote Schuur Hospital, Cape Town.

The records of 52 patients with amyloidosis admitted to Groote Schuur Hospital, Cape Town, between January 1969 and August 1982 were analysed. The male: female ratio was 1,3:1 and the mean age was 49,3 years. Forty-eight per cent of the patients had secondary amyloidosis, 21% had primary amyloidosis, 11,5% had localized amyloidosis and 11,5% had amyloidosis associated with multiple myeloma. Tuberculosis, chronic pulmonary sepsis and other chronic infections were present in 88% and rheumatoid arthritis in 16% of the patients with secondary amyloidosis. The commonest features at diagnosis were proteinuria (70%), oedema (52%) and hepatomegaly (39%). The diagnosis of amyloidosis was established by renal, liver and rectal biopsy (either singly or in combination) in 82% of cases. The prevalence of amyloidosis at autopsy was 0,28%.

Adult↗
PubMed1983

Differential reactivity of monoclonal antibodies with human colon adenocarcinomas and adenomas.

Monoclonal antibodies have been generated using membrane-enriched extracts of human metastatic mammary carcinoma lesions (Colcher et al., 1981), some of which demonstrated binding to the surface of human colon carcinoma cell lines. We report here an analysis of the reactivity of three of these monoclonal antibodies with formalin fixed tissue sections of human colon adenocarcinomas and adenomas. The three monoclonals employed were B72.3, which is reactive with a 220-400 kdal high molecular weight glycoprotein complex; B6.2, reactive with a 90 kdal glycoprotein, and B1.1, which is reactive with the 180 kdal glycoprotein CEA. B1.1 was least selective in its reactivity to colon carcinoma versus adenoma lesions. When 10 micrograms/ml of purified B1.1 IgG were used per slide, 94% (15 of 16) of carcinomas and 83% (15 of 18) adenomas showed reactivity. Monoclonal B72.3 demonstrated the most selective reactivity for carcinomas. Eighty-two percent (14 of 17) of carcinomas were positive while none of 18 adenomas examined showed reactivity with more than a few percent of adenoma cells positive. When a low concentration of purified B72.3 immunoglobulin was used per slide, 8 of 16 carcinomas and none of 46 adenomas or normal colon epithelium samples scored positive. Monoclonal B72.3 also reacted with cells in areas of "atypia" within adenomas. The reactivity of monoclonal B6.2 was intermediate as compared to B1.1 and B72.3 in its selectivity of reactivity for carcinoma cells. A heterogeneity in the populations of tumor cells showing reactivity with the three monoclonals was observed within many of the tumor masses. Both colon adenocarcinomas and adenomas can now be placed in several distinct groups based on their expression of antigens reactive with the three monoclonal antibodies employed.

Adenocarcinoma↗
PubMed1983

The analysis of soluble galactosyltransferase isoenzyme patterns using high resolution agarose isoelectricfocusing.

A high resolution method has been developed to separate the isoenzymes of galactosyltransferase by combining isoelectricfocusing (IEF) in 245 mm long agarose gels with a highly sensitive enzyme activity assay. The resolution and sensitivity is such that the isoenzyme pattern of 10 microliters human serum can be resolved. Using this method normal human serum was shown to contain at least 12 isoenzyme forms of galactosyltransferase, the major forms having isoelectric points of 4.33, 4.43, 4.51, 4.61, 4.74, 4.87, 4.96, 5.16 and 5.23. Part of the isoenzyme pattern complexity is due to sialylation of some isoenzymes. Alpha-lactalbumin-affinity chromatography, a method widely used in the purification of galactosyltransferase, causes a preferential purification of some of the isoenzyme forms.

Ascitic Fluid↗
PubMed1982

Comparison of biochemical properties of platelet monoamine oxidase in mentally disordered and healthy individuals.

We have investigated some biochemical properties of platelet monoamine oxidase (MAO) isolated from chronic schizophrenic and agoraphobic patients, nonschizophrenic institutional controls, and healthy volunteers. The enzyme activity level in the healthy population was reasonably constant over at least a 6-week period. High correlations were found between MAO activity assessed for different substrates (p-tyramine, beta-phenylethylamine, and tryptamine). Some heterogeneity of the platelet MAO may exist, however, at least in some of the chronic schizophrenics, since the substrate specificities were changed and the Km values reduced. The half-life of the enzyme at 58 degrees C was 2-3 minutes and the transition temperature derived from Arrhenius plots was 16-17 degrees C with respect to beta-phenylethylamine. Platelet MAO from chronic schizophrenics was not significantly different from control values with respect to temperature effects. SDS-polyacrylamide gel electrophoresis of the 3H-pargyline-MAO adduct revealed that the subunit of platelet MAO is a single band protein with a molar individuals. The adjacent structure of the flavine site of the platelet MAO was chromatographically identical to the penta-peptide isolated from MAOs from other tissues. The response of platelet MAO to thimerosal, a new differential type A MAO inhibitor, could be distinguished not only from type A MAO isolated from human placenta, but also from type B MAO isolated from bovine liver.

Agoraphobia↗