摘要:

Previously the authors have observed a reduction of the ventricular fibrillation threshold (VFT) in a mild diabetic model. This investigation examines the role of more severe hyperglycemia in altering the ventricular fibrillation threshold and how the sympathetic nervous system modulates the response. Alloxan diabetes was induced in eight male mongrel dogs 3–5 years of age (Group 2), for comparison with matched controls (Group 1). Hemoglobin A1crose from 2.9 ± .4–7.8 ± .3% and body weight was maintained with daily insulin. After 1 year, anesthesia was induced with chloralose and an electrode catheter placed at the right ventricular apex. VFT was 41.7 ± 1.8 ma in Group 1 and 27.8 ± 2.1 ma in the diabetics of Group 2 (p < .001). There was significantly greater decline of VFT in response to epinephrine infusion in Group 2. The threshold in diabetics rose to normal levels after infusion of the beta-blocking agent, esmolol. Subsequently, the response of the cardiac sympathetic system was assessed during ventricular pacing at 200 beats/minute. Serial paired blood samples were taken from catheters in the aorta and coronary sinus for catecholamine assay by HPLC. Both groups had similar coronary blood flow responses by the thermal method, as well as changes in arterial pressure. While no change occurred in Group 1, a progressive rise of norepinephrine (NE) concentration was observed in coronary venous effluent of Group 2 (p < .01). The basal arterial-coronary sinus difference was −123 ± 52 pg/ml, which rose during pacing in Group 2 to a peak of −376 ± 9.3 pg/ml. Ischemia appeared unlikely in view of the normal myocardial lactate extraction and coronary blood flow response as well as morphologically intact mitochondria. The observations of this study are consistent with the view that enhanced ventricular vulnerability in diabetes is associated with altered sympathetic activity in myocardium.

ISSN:0002-9629    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Danazol, an attenuated androgen, has been used successfully at its conventional dose (400–800 mg/day) in the treatment of idiopathic thrombocytopenic purpura (ITP). To minimize side effects, the authors tried a very low dose (50 mg/day) regimen which has not been used in any other disease and observed its efficacy in ITP. Fifteen patients were given this dosage of danazol. Its effects on T-cell subsets, B cells, and blastogenic response to pokeweed mitogen (PWM) and staphylococcus aureus (Staph A) were studied before and during therapy. The percentage of CD3 and the percentage and numbers of CD4 were significantly increased during therapy. Responses to PWM, a T-cell dependent B cell mitogen, were also significantly elevated during therapy. However, no change in the percentage of B (CD19) lymphocytes and response to Staph A, a polyclonal B cell mitogen, were noted. There were seven excellent-good and eight fair-poor responses in platelet counts. The excellent-good responders were found to have a more stable CD4 subset between before and during therapy compared to the fair-poor responders (p < 0.05, Fisher's exact test). Very low dose danazol regimen, therefore, produced a significant increase in the CD4 without affecting the B cells. However, the excellent-good responder patients showed no significant increase in the CD4 lymphocytes.

ISSN:0002-9629    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

The authors investigated the reductive effects of a Kunitz-type proteinase inhibitor, urinastatin, on the nephrotoxicity seen in lung cancer patients treated with cisplatin by measuring N-acetyl-β-D-glucosaminidase (NAG) activity and β2-microglobulin (BMG) content in 24 hour urine, creatinine clearance, blood urea nitrogen (BUN), serum creatinine, uric acid, and BMG as factors of nephrotoxicity. In control patients treated with anticancer drugs containing cisplatin but no supplemental urinastatin, the 24 hour urine NAG and BMG levels increased more than three-fold over the pretreatment levels, 3 days after anticancer therapy, respectively. Creatinine clearance significantly decreased and levels of BUN, serum uric acid, and BMG in control patients significantly increased over the corresponding pretreatment levels, 3 days after anticancer therapy. However, supplemental urinastatin reduced abnormalities in levels of all these factors 3 days after therapy. These results suggest that supplemental urinastatin protects from cisplatin-induced nephrotoxicity, especially proximal tubular damage.

ISSN:0002-9629    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

The authors previously demonstrated that arginine vasopressin (AVP) lowers pulmonary artery pressure in rats with hypoxic pulmonary hypertension by activation of the V1receptor. The pulmonary depressor effect of AVP in hypoxia-adapted rats is not due to its effect on cardiac output. The current study tested two alternative hypotheses: that AVP lowers pulmonary artery pressure in the hypoxia-adapted lung by (1) dilating pulmonary vasculature directly, or (2) releasing atrial natriuretic peptide (ANP) from the heart. The first hypothesis was tested by injecting AVP into the pulmonary arteries of isolated, buffer perfused lungs and monitoring pulmonary artery pressure, and by exposing preconstricted pulmonary artery rings to graded doses of AVP and monitoring the tension generated. AVP caused minimal vasodilation in perfused lungs and only a small vasodilator effect in pulmonary artery rings. The second hypothesis was tested by injecting AVP (160 ng/kg) or vehicle intravenously in conscious hypoxia-adapted (4 weeks) or air control rats and measuring ANP in arterial blood and atria, and by testing pretreatment with the V1receptor antagonist d(CH2)5Tyr(Me)AVP (130 ng/kg) on the AVP-induced increase in plasma ANP. AVP produced a 7-fold increase in plasma ANP (209 ± 33 to 1346 ± 233 pg/ml; p < 0.05) in hypoxiaadapted rats and a 5-fold increase in ANP (122 ± 22 to 573 ± 174 pg/ml; p < 0.05) in air controls. ANP release was abolished by pretreatment of both groups with d(CH2)5Tyr(Me) AVP. The AVP-induced ANP release came mainly from left atrium. These data strongly suggest that the pulmonary depressor effects of AVP in hypoxia-adapted rats is due to augmented V1receptor-induced release of ANP from left atrium.

ISSN:0002-9629    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Blood gas analysis is crucial for the proper evaluation of systemic acid-base disorders, but several reports have been critical of the current approach which relies on the Henderson-Hasselbalch equation and other possibly erroneous assumptions about the bicarbonatecarbonic acid buffer system of blood. This report studied renal failure patients receiving dialysis and nondialyzed medical patients with respect to variations of the pK'1of carbonic acid dissociation and discrepancies between measured and calculated bicarbonate. Among dialyzed patients, the mean pK'1differed significantly from 6.10, and a significant difference was found between calculated and measured total CO2even though all assays were performed on the same arterial blood. Significant correlations were observed between pK'1and calculated-measured total CO2as well as serum phosphate converted to mEq/1 in the dialyzed group. These data suggest that there is a need to reevaluate current acid-base analysis, especially as it is applied to very seriously ill individuals.

ISSN:0002-9629    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Elevations of atrial natriuretic peptide (ANP) in congestive heart failure (CHF) and chronic obstructive lung disease (COLD) are presumably due to atrial hypertension, while secondary hyperaldosteronism in these patients is thought to result from diminished renal perfusion. The responsiveness of the ANP and renin (PRA)-aldosterone (PA) systems to acute increases in right atrial pressure has not been studied in these patients, but in normals a reciprocal relationship betweenANPwithPRAandPAhas been shown. The authors monitored venous pressure (VP, reflective of right atrial pressure),ANP, PRAandPAin 15 stableCOLDpatients, seven stableCHFpatients and three normal controls at baseline and after elevation ofVPby antishock trousers. Inflation of the trousers resulted in increasedVPandANP(p < 0.05): controlANP, 84 ± 17to108 ± 23pg/ml;COLD ANP, 176 ± 5 to 200 ± 7; and CHF ANP, 388 ± 20 to 499 ± 37. PRAandPAwere not suppressed by increasingANPlevels and the deltaANPdeltaVPratio was similar among groups. No intergroup differences in restingPRAandPAwere noted, butPRAwas higher (p = 0.007) andPAtended to be higher (p = 0.08) in a sub-group of six edematous patients, as compared with non-edematous patients and controls. These findings: (1) confirm previously reportedANPdifferences betweenCOLDandCHF; (2indicate that theANPsystem remains responsive to physiologic manipulations inCOLDandCHF; and (3) demonstrate thatANPand thePRA-PAaxis are not reciprocally related in either group.

ISSN:0002-9629    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Over the last several years a number of new and potent antiarrhythmic agents have been developed. One of these promising new drugs, propafenone hydrochloride (Rhyth-mol*), will soon be available for use in this country. Although similar in some aspects to flecainide and encainide, the drug possesses some unique characteristics. The purpose of this review is to summarize the pharmacologic and physiologic effects of propafenone and to outline its clinical use.

ISSN:0002-9629    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Mucormycosis is an opportunistic invasive infection caused by fungi of the order Mucorales. Rhizopus, Absidia, and Mucor are the most commonly encountered genera. Disease is characterized by vascular invasion, thrombosis, and tissue necrosis. Rhinocerebral disease is the most common manifestation but pulmonary, cutaneous, gastrointestinal, and widely disseminated forms have been reported. Pulmonary and disseminated disease are usually seen in neutropenic patients with leukemia or lymphoma. Both present as fever and unexplained pulmonary infiltrates unresponsive to antibacterials and corticosteroids. Disease is usually fulminant and has a high mortality rate. Diagnosis is most commonly made at autopsy. A single case of disseminated disease is reported that is unusual in its subacute course and its occurrence in an otherwise healthy non-neutro-penic diabetic male.

ISSN:0002-9629    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

A young male IV drug abuser with multiple AIDS risk factors and positive HIV se-rology presented with acute onset of painful urinary retention as a result of a parasympa-thetic mononeuropathy. Because no other explanation could be found for his illness, despite a careful search for the most likely etiologic agents, the authors propose that his symptom complex may have resulted from infection with the AIDS virus. A review of the current literature relevant to the peripheral neuropathy associated with AIDS is presented.

ISSN:0002-9629    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Neuropsychiatric complications, such as metabolic encephalopathy, are common occurrences in end-stage renal disease (ESRD) patients. Frequently, metabolic encephalopathy develops in relationship to the multiple pharmacologic therapies routinely employed in this population. Such polypharmacy often leads to adverse drug reactions, drug-drug interactions, or dosage error. In this regard, over-the-counter (OTC) medications are commonly perceived as being “somewhat benign” when, in fact, their potential for adverse effect may be significant. The authors describe the course of a 64-year-old hemodialysis patient who became intoxicated on conventional doses of pseudo-ephedrine only to regain neurologic integrity upon discontinuation of the medication.

ISSN:0002-9629    

出版商:OVID    

年代:1989

数据来源: OVID