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Biomedical subjects

J Joseph

Publications and source records attributed to J Joseph.

At least 127 records · Page 7Linked to original sources
PubMed1994

Fate of side branches after intracoronary implantation of the Gianturco-Roubin flex-stent for acute or threatened closure after percutaneous transluminal coronary angioplasty.

Side branch occlusion may occur in the course of percutaneous transluminal coronary angioplasty (PTCA), particularly if complicated by site dissection. Concern that the additional placement of a stent may further jeopardize side branches is logical. Consequently, this study analyzed pre-PTCA, post-PTCA, poststent, and 6-month follow-up angiograms of 100 consecutive patients in whom 103 Gianturco-Roubin stents were implanted for acute or threatened closure after PTCA. Side branches were defined as major (> 50% of the stented vessel diameter) and minor (< 50%). Minor branches, often < 1 mm in diameter, were assessed only for patency. One hundred eight major branches, of which 33 were diseased (> 50% stenosis), and 129 minor branches were analyzed. Seven major branches (6%), all of which were diseased before PTCA, and 23 minor branches (18%) were lost after PTCA. Immediately after stent insertion, only 1 additional major and 1 minor branch were lost, whereas 2 of 7 major (29%) and 9 of 23 minor (39%) branches reappeared. At follow-up angiography, 7 major branches (6%) were more stenosed and 6 (6%) were improved compared with the angiogram before PTCA. Only 2 major (2%) and 5 minor (4%) branches remained occluded. Additionally, 2 major and 1 minor branch, which were patent after PTCA and stenting, were occluded at follow-up as a result of total occlusion of the stented segment.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1994

BR-16A protects against ECS-induced anterograde amnesia.

BR-16A is an herbal (non allopathic) medication used in India to enhance cognition. In experiment 1, 28 Wistar rats received either BR-16A (200 mg/kg/day) or vehicle alone for 3 weeks. During the third week, the rats were tested for learning in the Hebb Williams complex maze. BR-16A-treated rats showed significantly better learning than did controls. Experiment 2 was conducted identically except that during the second week all of 32 rats additionally received six once-daily electroconvulsive shocks (ECS). An advantage for learning was again demonstrated for the BR-16A group. It is concluded that BR-16A facilitates learning, and that this effect extends to a protection against ECS-induced anterograde amnesia. Cognitive deficits induced by electroconvulsive therapy are a major disadvantage of the treatment and, to-date, no drug has been found to offer satisfactory protection against such deficits. It is suggested that BR-16A may hold promise in the containment of electroconvulsive therapy (ECT)-induced cognitive compromise.

Amnesia↗
PubMed1994

In vivo pharmacokinetics of nitroxides in mice.

The in vivo reduction kinetics of twenty different nitroxide compounds in mice has been investigated by using an electron paramagnetic resonance (EPR) spectrometer, equipped with an S-band loop-gap resonator, operating at 3.5 GHz. The diameter of the resonator (4 mm) fits well the tip of the mouse tail, thus allowing the direct detection of in vivo free radicals in the blood circulation. After intravenous injection, the nitroxide signal in the circulation of the mouse tail was followed with time; no anesthetic agent was used. For the pyrrolidine nitroxides (five-member rings) with different functional groups, the t1/2 values followed the order: = O > COO- > OH > CONH2 approximately CH2NH2 > NH2. A different trend was obtained for the piperidine nitroxides (six-member rings): COO- > CH2NH2 > OH approximately NH2 > CONH2 > = O. The most striking observation was that while the t1/2 value of the cabonyl pyrrolidine is the longest among all the nitroxides tested for this property, that of the carbonyl piperidine is the shortest. Comparison of the in vivo decay kinetics of six pairs of pyrrolidine nitroxides and piperidine nitroxides with same functional groups showed that the t1/2 values of the former are 2 to 28 times longer than the latter. It is concluded here that the pyrrolidine nitroxides are more resistant to cellular metabolism in vivo when compared to the piperidine nitroxides.

Animals↗
PubMed1994

The oxidation of alpha-tocopherol and trolox by peroxynitrite.

Peroxynitrite reacts rapidly with alpha-tocopherol to generate a mixture of species. The predominant products are 8a-methoxytocopherone in methanol and alpha-tocopherylquinone in acetonitrile. Only a small fraction (about 2% of original alpha-tocopherol) was detected as alpha-tocopheroxyl radical in either solvent. We propose that peroxynitrite oxidizes alpha-tocopherol in a two-electron process yielding the alpha-tocopherone cation. The two-electron oxidation may be either concerted or sequential. The fate of the alpha-tocopherone cation is solvent dependent. In acetonitrile it undergoes hydrolysis, in the presence of trace amounts of water, to form alpha-tocopherylquinone. In methanol it undergoes nucleophilic addition to yield 8a-methoxytocopherone. Our data suggest that two-electron oxidation of alpha-tocopherol by peroxynitrite represents the major pathway, whereas one-electron oxidation to generate alpha-tocopheroxyl radical is a minor pathway. The biological consequences of two-electron oxidation of alpha-tocopherol are discussed.

Acetonitriles↗
PubMed1994

Sexual behavior research on a cohort of gay men, 1984-1990: can we predict how men will respond to interventions?

In 1984, over 1000 gay and bisexual men volunteered to participate in both the Chicago Multicenter AIDS Cohort Study (MACS) and a companion psychosocial study, the Coping and Change Study (CCS). Participants in the semiannual Chicago MACS/CCS evaluations comprise the largest cohort of high-risk men under continuous medical, behavioral, and psychosocial observation. Chicago MACS/CCS researchers prospectively chart the sexual behavior change patterns of the cohort and relate those behavioral changes to psychosocial correlates and actual HIV infection risk. This report summarizes the behavioral natural history of the Chicago MACS/CCS cohort from 1984 to 1990, focusing on receptive anal sex practices and use patterns for alcohol and the most frequently used recreational drugs. As these are prospective observational and not controlled intervention studies, psychosocial correlates of sexual behavior change by members of the cohort are suggestive of factors influencing behavior change rather than indicative of causal relationships. However, the voluntary availability to participants in the Chicago MACS/CCS of HIV-1 antibody test results beginning in late 1985 provided the opportunity to examine whether demographic, psychosocial, or behavioral factors were indicators of sexual behavior change following disclosure and counseling about HIV-1 serostatus. Recommendations for promotion and maintenance of safer sexual behavior for the long run, and limitations in the generalizability of these findings to the much more diverse populations of men who have sex with other men conclude this article.

Acquired Immunodeficiency Syndrome↗
PubMed1994

In vitro characteristics of 'undercollected' units of whole blood in CP2D-A.

Blood donation volumes less than 350 ml are classified as 'undercollected' at the NSW Red Cross Blood Transfusion Service (BTS) and are discarded. This study evaluated the in vitro characteristics during storage of both undercollected units and units of acceptable volume. Thirty-two units of whole blood were each collected into 63 ml of CP2D-A, with blood volumes ranging from 180 to 456 ml. The units were stored between 4 and 6 degrees C for 35 days and in vitro measurements were performed weekly. Biochemical parameters measured included ATP, extracellular pH, total haemoglobin, haematocrit, mean cell volume, plasma sodium and potassium, plasma haemoglobin, 2,3-DPG and lactate levels. All parameters were within the BTS acceptable quality control limits for whole blood. Thus, it appears feasible to transfuse undercollected units with volumes between 180 and 350 ml. However, routine transfusion of undercollected homologous units is undesirable. In contrast, it may be preferable to transfuse an autologous unit, even if it was undercollected. The performance of in vivo survival studies would provide confirmatory data on this proposition.

2,3-Diphosphoglycerate↗
PubMed1994

Study of a new tumor marker, CYFRA 21-1, in malignant and nonmalignant diseases.

The diagnostic value of a new tumor marker, CYFRA 21-1, was studied in the sera of 50 controls, 206 patients with benign diseases and 469 patients with malignancies. Fifty controls showed mean serum concentrations of 1.2 +/- 0.5 ng/ml. Using 3.3 ng/ml as the cutoff, abnormal CYFRA levels were found in 13.1% of patients with benign diseases, mainly in those with liver cirrhosis (29.4%) or renal failure (20.8%), and in 44.4% (180/405) of patients with active cancer. Neither healthy subjects nor no evidence of disease (64 cases) patients had serum levels higher than this limit. CYFRA 21-1 results were significantly higher in patients with active cancer than in those with benign diseases or without active tumors (p < 0.0001). CYFRA serum levels were significantly higher in patients with metastases (59.5%) than in those with locoregional disease (33.7%; p < 0.001). CYFRA 21-1 sensitivity in patients with lung cancer was related to tumor histology with abnormal levels in 65.6% of patients with non-small cell lung cancer and in 25% of patients with small cell lung cancer (p < 0.0001). In breast cancer, CYFRA 21-1 concentrations were significantly higher in patients with metastases and in patients with primary tumors but with nodal involvement (p < 0.001).

Biomarkers, Tumor↗
PubMed1994

Seronegative antiphospholipid syndrome associated with plasminogen activator inhibitor.

Antiphospholipid syndrome is characterized by thrombosis, recurrent fetal loss, thrombocytopenia and is associated with the presence of antiphospholipid antibodies, especially anticardiolipin antibodies. We present a patient with the clinical features of antiphospholipid syndrome, namely recurrent venous and arterial thrombosis, recurrent abortions, thrombocytopenia and libido reticularis but with persistently negative serology for any type of antiphospholipid antibody. The possible existence of 'seronegative' antiphospholipid syndrome is proposed. Of additional interest in this patient is the presence of significantly elevated levels of plasminogen activator inhibitor. The role of this inhibitor, if any, in the antiphospholipid syndrome and/or seronegative antiphospholipid syndrome is not known and merits further study.

Adult↗
PubMed1994

Penetration of intravenous and oral ciprofloxacin into sterile and empyemic human pleural fluid.

OBJECTIVE: To compare the penetration of oral and intravenously administered ciprofloxacin into infected (empyemic) and noninfected (sterile) human pleural fluid. DESIGN: Eleven men and 5 women (aged 29-76) were consecutively selected from adult patients referred to the respiratory unit for pleural effusion. In this open-label, prospective trial, 13 patients with sterile pleural effusions were nonrandomly assigned to receive either ciprofloxacin 200 mg (single intravenous dose), 750 mg (single oral dose), or 750 mg (two oral doses per day for 3 days); 3 patients with infected pleural effusions received 750 mg oral doses for 10 days. Simultaneous pleural fluid and venous blood specimens were drawn over 5 hours after single dose or when steady-state was attained, and ciprofloxacin concentrations were measured by HPLC. RESULTS: Pleural fluid concentrations of ciprofloxacin equaled plasma concentrations 1.5 hours after 200 mg was given intravenously and the pleural/plasma ratio remained > or = 0.9 for 4 hours. After a single 750-mg oral dose, pleural ciprofloxacin concentrations rose from 0 to 1.4 micrograms/mL over 5 hours with the highest pleural fluid/plasma ratio (0.7) at 5 hours. Average steady-state ciprofloxacin concentrations in sterile pleural fluid after 750 mg administered twice daily for 3 days, ranged between 1.1 and 1.8 micrograms/mL with ratios between 0.3 and 0.9 over 4 hours. In empyemic pleural fluid at the same dosage, average steady-state ciprofloxacin concentrations ranged between 1.9 and 3.4 micrograms/mL with ratios between 1.0 and 2.0 over 5 hours. CONCLUSIONS: Oral ciprofloxacin penetrates into sterile and empyemic pleural fluid with concentrations 30-90 percent and 100-200 percent of plasma concentrations, respectively.

Administration, Oral↗
PubMed1994

Thoracic endometriosis. Recurrence following hysterectomy with bilateral salpingo-oophorectomy and successful treatment with talc pleurodesis.

This is a report of an unusual patient who had four of the five manifestations of thoracic endometriosis, including right pneumothorax, left hemothorax, chest pain, and hemoptysis. This patient shows that recurrence of symptoms can occur while a patient is receiving hormonal replacement therapy even after hysterectomy and bilateral salpingo-oophorectomy; estrogen replacement should probably be delayed for several months to allow complete regression of the ectopic endometrial tissue. Alternatively, chemical pleurodesis can be effective in treating recurrent pneumothorax or hemothorax while the patient is receiving hormonal replacement. Bilateral pleural involvement and hemoptysis suggest microembolization of endometrial tissue as the pathogenic mechanism for thoracic endometriosis.

Adult↗
PubMed1994

Lack of protection of PBN in isolated heart during ischemia and reperfusion: implications for radical scavenging mechanism.

We evaluated the ability of alpha-phenyl-tert-butyl nitrone (PBN) to trap free radicals and to protect the rat myocardium during ischemia and reperfusion. Isolated bicarbonate buffer-perfused hearts (n = 8) were subjected to 20 min global ischemia (37 degrees C) followed by reperfusion with 0.4 to 4.0 mM PBN. Coronary effluent containing the PBN adduct was extracted in toluene. Electron spin resonance analysis of the toluene extract revealed a PBN-hydroxyl adduct. To verify this assignment, a Fenton system was used to generate an authentic PBN-hydroxyl adduct (n = 8), which yielded the same ESR spectra as the reperfusion-derived adduct. The structure of the adduct formed in the Fenton system was confirmed by gas chromatography-mass spectrometry. The ESR parameters of the PBN-hydroxyl adduct were exquisitely sensitive to solvent polarity during extraction of the adduct. Extraction of an authentic PBN-hydroxyl adduct into chloroform, chloroform:methanol, and toluene closely matched the ESR parameters obtained during reperfusion of ischemic myocardium in other animal models. To determine whether PBN could confer any protective effect during ischemia or reperfusion, hearts (n = 8/group) were subjected to 35 min global ischemia at 37 degrees C with the St. Thomas' II cardioplegic solution followed by 30 min reperfusion. Percent recovery (mean +/- SEM) of developed pressure, rate pressure product, and leakage of lactate dehydrogenase during reperfusion in control hearts were 58 +/- 3%, 48 +/- 4% and 3.2 +/- 0.5 IU/15 min/g wet wt. PBN at a concentration of 0.4 mM or 4.0 mM when present either during ischemia alone or reperfusion alone did not exert any effect upon recovery of developed pressure, rate pressure product or post-ischemic enzyme leakage. We conclude that PBN fails to improve contractile recovery and reduce enzyme leakage during reperfusion of myocardium subjected to global ischemia.

Animals↗
PubMed1994

Potentials associated with the Go/No-Go paradigm in traumatic brain injury.

Surface event-related potentials associated with visually triggered movements (Go) and the inhibition of planned movements (No-Go) were examined in seven healthy subjects and five postacute traumatic brain injured (TBI) subjects. Analysis showed that the cortical potential P1-N1 was similarly affected by condition in both the control and TB1 groups. Although TB1 subjects showed smaller P1-N1 amplitudes (Go = 2.91 uV; No-Go = 3.95 uV; p < .03) relative to control subjects (Go = 4.82 uV; No-Go = 6.03 uV; p < .03), both groups showed larger amplitudes in the No-Go condition. A bipolar lead (C3'-C3") over the sensorimotor cortex showed a reversal of polarity between Go and No-Go conditions which was synchronized with the EMG activity in all control subjects. This signal reversal and timing of potentials was absent in four of the five TB1 subjects' waveforms, suggesting difficulty in sensorimotor processes associated with movement control. In addition, TB1 subjects displayed a number of atypical stimulus-locked waveforms, which are discussed relative to the specific functional impairments of individual subjects. The results highlight the potential usefulness of such paradigms as the Go/No-Go procedure in the analyses of electroencephalographic waveforms and of the effects of TBI.

Adolescent↗
PubMed1994

ECT-induced anterograde amnesia: can the deficits be minimized?

To date, no pharmacological agent has been confirmed to lessen electroconvulsive therapy (ECT)-induced memory deficits. BR-16A is an herbal preparation, containing various organic extracts, used in India for the enhancement of cognition (among other applications). In the present study, adult male Sprague-Dawley rats received six once-daily electroconvulsive shocks (ECSs). Half the animals were treated with BR-16A (200 mg/kg/day) for 1 week before ECS, during the ECS course, and during the post-ECS learning assessment phase; the remaining animals received vehicle alone. In experiment 1, rats (n = 16/treatment group) were preassessed for learning on days 3 and 5 of exposure to the Hebb-Williams complex maze and were reassessed after comparable exposure to the maze starting from the second day post-ECS. In experiment 2, rats (n = 9/treatment group) were preassessed for number of trials to satisfactory learning and number of wrong arm entries in a T-maze and were reassessed on the second day post-ECS. The learning preassessments were conducted just prior to the commencement of the BR-16A/vehicle treatments. In both experiments, rats receiving BR-16A performed significantly better than controls. It is concluded that BR-16A protects against ECS-induced anterograde amnesia. BR-16A may therefore have scope in minimizing ECT-induced learning deficits.

Amnesia, Retrograde↗
PubMed1993

Inhibition of low-density lipoprotein oxidation by nitric oxide. Potential role in atherogenesis.

The effects of nitric oxide (.NO) and nitrovasodilators on the oxidation of low-density lipoprotein (LDL) have been studied. S-Nitroso-N-acetylpenicillamine (SNAP) and sodium nitroprusside (SNP) inhibited Cu(2+)- and 2,2'-azobis-2-amidinopropane hydrochloride-dependent oxidation of LDL as monitored by oxygen consumption and the formation of thiobarbituric acid-reactive substances, conjugated dienes, and lipid hydroperoxides. In the case of SNP, inhibition of LDL oxidation occurred only when the incubation mixture was irradiated with visible light. SNAP, however, exerted a dose-dependent inhibition of Cu(2+)-catalyzed oxidation of LDL even in the dark. Addition of .NO dissolved in deoxygenated buffer also inhibited the progression of LDL oxidation. Mouse peritoneal macrophages were less able to degrade LDL that had been oxidized in the presence of SNAP. Using an .NO electrode, it was estimated that a continuous production of .NO (< or = 760 nM/min) could retard the progression of LDL oxidation. We propose that .NO can inhibit LDL oxidation by acting as a chain-breaking antioxidant that is capable of scavenging carbon-centered and peroxyl radicals. Biological implications of this novel .NO antioxidant property are discussed in relation to atherogenesis and contrasted to the prooxidant property of .NO when generated in the presence of superoxide.

Animals↗
PubMed1993

Site-specific trapping of reactive species in low-density lipoprotein oxidation: biological implications.

Abundant data suggest that the oxidative modification of low-density lipoprotein is mediated by lipid-derived free radicals and aldehydes derived from them. In this report we have addressed the site-specific aspects of low-density lipoprotein modification. To this end, both water-soluble and lipid-soluble spin traps (i.e., diamagnetic organic molecules containing nitroso or nitrone functional groups) were used. Radical adducts were detected by electron spin resonance-spin trapping technique. Biochemical indices of low-density lipoprotein modification were thiobarbituric acid reactive substances formation, electrophoretic mobility and macrophage-mediated uptake of oxidized low-density lipoprotein. Results from this study have shown that the lipophilic spin trap, alpha-phenyl-tert-butyl-N-nitrone, traps a primary low-density lipoprotein lipid-derived radical, while also inhibiting the total oxidative modification in a dose-dependent manner. The more hydrophilic analog, i.e., alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone, appeared to trap the secondary alkyl radicals and did not exert any inhibitory effect on oxidative modification of low-density lipoprotein. The lipophilic nitroso spin trap, 2-methyl-2-nitroso propane, which traps a lipid-derived radical, inhibited the low-density lipoprotein modification as did the water-soluble nitroso analog, 2-hydroxymethyl-2-nitroso propane. However, the water-soluble nitroso analog did not trap the lipid radical. The inhibitory effect of 2-hydroxymethyl-2-nitroso propane was tentatively attributed to trapping of aldehydes. It is conceivable that spin traps can inhibit the oxidative modification of low-density lipoprotein by trapping of the lipid radicals as well as trapping aldehydes formed from lipid peroxidation.

Animals↗
PubMed1993

Pleural effusions in hospitalized patients with AIDS.

OBJECTIVE: To determine the incidence, cause, and characteristics of pleural effusions in hospitalized patients with the acquired immunodeficiency syndrome (AIDS). DESIGN: Retrospective. PARTICIPANTS: A total of 222 patients with AIDS hospitalized between January 1986 and January 1992 at the Medical University of South Carolina hospitals. RESULTS: Pleural effusions occurred in 59 patients for an overall incidence of 27%. The mean age of the patients was 35 +/- 2 years (SE) and the male to female ratio was 5:1. The cause was infectious in 39 (66%) patients, noninfectious in 18 (31%), and unknown in 2 (3%). Pleural effusions were caused by bacterial pneumonia in 18 (31%) patients, Pneumocystis carinii pneumonia in 9 (15%), Mycobacterium tuberculosis in 5 (8%), septic embolism in 2 (3%), Nocardia asteroides in 2 (3%), cryptococcus neoformans in 2 (3%), and Mycobacterium arium intracellulare in 1 (2%). Among noninfectious causes (n = 18), hypoalbuminemia was the cause in 11 patients (19%), cardiac failure in 3 (5%), and atelectasis, Kaposi sarcoma, uremic pleurisy, and adult respiratory distress syndrome in 1 (2%) each. Patients with AIDS who had pleural effusions had significantly lower serum albumin levels and had lower CD4 counts than did those without pleural effusions (P < 0.001). CONCLUSIONS: Pleural effusions are common in hospitalized patients with AIDS. Bacterial pneumonia is the most common cause for pleural effusion in AIDS. Large effusions are associated with Kaposi sarcoma and tuberculosis. Hypoalbuminemia is a common cause of noninfectious pleural effusions.

AIDS-Related Opportunistic Infections↗