Correlations of purinergic, cholinergic and adrenergic functions in rabbit corporal cavernosal tissue.

Erection involves cholinergic, adrenergic as well as non-cholinergic non-adrenergic nerves. Endothelial-derived relaxation factor plays an important role in mediating smooth muscle relaxation, which is crucial in initiating and maintaining erection. We previously showed that adenosine 5'-triphosphate (ATP) can induce significant relaxation in rabbit corporal cavernosal tissue. The present study presents effects of different neurotransmitters and the role of endothelium in controlling the contractile/relaxant status of rabbit cavernosal tissue. These studies utilized isolated tissue strips prepared from the corpus cavernosum of sexually mature male New Zealand white rabbits. The results can be summarized as follows: (1) field stimulation caused relaxations with rebound contractions in most strips; (2) bethanechol (250 microM), isoproterenol (20 microM) and ATP (1 mM) all induced relaxations, though the relaxation induced by bethanechol was poorly sustained; (3) removal of the endothelium by rubbing decreased the relaxation to field stimulation and virtually eliminated the relaxation induced by bethanechol, but had no effect on the relaxation responses to isoproterenol and ATP; (4) methoxamine (200 microM) stimulated a sustained contraction of corporal cavernosal tissue, an effect unaltered by rubbing the strips; (5) low dose epinephrine induced relaxation, whereas higher concentrations contracted the tissue, and (6) beta-adrenergic inhibition with propranolol (20 microM) was significantly more effective than mascarinic blockade with atropine (20 microM) in eliminating relaxation caused by field stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Surface spectrofluorometry of the rabbit urinary bladder

Proper function of the urinary bladder is dependent on the delivery of a normal supply of blood, oxygen, and nutrients to the tissue. The smooth muscle elements of the bladder utilize metabolic energy in the form of ATP and other high-energy compounds to support bladder contraction. One of the first metabolic indications of contractile activity would be alterations in the oxidative state (redox) of the tissue, which is reflected by the NADH/ NAD ratio. NADH is a metabolic intermediate synthesized during substrate metabolism and utilized during energy production and utilization. We have studied NADH metabolism in the in vitro bladder strip preparation utilizing a surface spectrofluorometer. This instrument monitors NADH fluorescence in tissue preparations with the use of an optical fiber probe placed on the serosal surface of the strip. The bladder strips displayed rhythmic contractile activity. This was correlated with alterations in NADH fluorescence. There was an excellent correlation (correlation coeficient of 0.986) between the frequency of the spontaneous activity of both contraction and fluorescence. An increase in tension was followed (in seconds) by a decrease in fluorescence. The basal NADH fluorescence was modulated by metabolic inhibitors as would be expected by their metabolic actions: Anoxia and sodium azide (metabolic inhibitors of oxidative phosphorylation) produced a marked increase in the redox state (NADH fluorescence), whereas DNP (a mitochondrial uncoupler) produced a marked decrease. Bethanechol stimulated an increase in tension and a reduction in fluorescence. The above findings suggest that NADH surface spectrofluorometry reflects NADH metabolism in the detrusor smooth muscle and that fluctuations in such spectra correlate well with functional activity. NADH surface spectrofluorometry displays potential as a noninvasive method of monitoring one aspect of detrusor metabolism.     

Effect of Donor Factors on Early Graft Survival in Adult Cadaveric Renal Transplantation

Previous studies of the effect of donor factors on renal transplant outcomes have not tested the role of recipient body mass index, donor/recipient weight ratios and age matching, and other factors. We analyzed 20,309 adult (age 16 or older) recipients having solitary cadaveric renal transplants from adult donors from 1 July 1994 to 30 June 1998 in an historical cohort study (the 2000 United States Renal Data System) of death censored graft loss by the Cox proportional hazards models, which corrected for characteristics thought to affect outcomes. The only independently significant findings in Cox Regression analysis were a high donor/ recipient age ratio (> or = 1.10, e.g. a 55-year-old donor given to a recipient age 50years or younger, adjusted hazard ratio (AHR) 3.22, 95% confidence interval (CI) 2.36-4.39) and African American donor kidneys (AHR 1.64, 95% CI, 1.24-2.17). African American recipients and older donors were not at independently increased risk of graft failure in this model. Among donor factors, older donor kidneys given to younger recipients and donor African American kidneys were independently associated with graft loss in recipients of cadaver kidneys. The task for the transplant community should be to find the best means for managing all donor organs without discouraging organ donation.     

Hospitalized congestive heart failure after renal transplantation in the United States

PURPOSE: African Americans have increased risk for congestive heart failure (CHF) compared to Caucasians in the general population, but the risk of CHF in African American renal transplant recipients has not been studied in a national renal transplant population. METHODS: Therefore, 33,479 renal transplant recipients in the United States Renal Data System (USRDS) from 1 July, 1994 to 30 June, 1997 were analyzed in an historical cohort study of the incidence, associated factors, and mortality of hospitalizations with a primary discharge diagnosis of CHF [International Classification of Diseases-9 (ICD9) Code 428.x]. RESULTS: African American renal transplant recipients had increased age-adjusted risk of hospitalizations for congestive heart failure compared to African Americans in the general population [rate ratio 4.60, 95% confidence interval (CI) 4.59-4.62]. In logistic regression analysis, African American recipients had increased risk of congestive heart failure after renal transplantation, independent of other factors. Among other significant factors associated with congestive heart failure, the strongest were graft loss and allograft rejection. No maintenance immunosuppressive medications were associated with CHF. In Cox regression analysis patients hospitalized for CHF had increased all-cause mortality compared with all other recipients (hazard ratio 3.69, 95% CI, 2.23-6.10), but African American recipients with CHF were not at significantly increased risk of mortality compared to Caucasian recipients with CHF. CONCLUSIONS: African Americans recipients were at high risk for CHF after transplant independent of other factors. The reasons for this increased risk should be the subject of further study. All potential transplant recipients should receive particular attention for the diagnosis and prevention of CHF in the transplant evaluation process, which includes preservation of allograft function.     

HIV seroprevalence among tuberculosis patients in Nkembo Hospital, Libreville, Gabon. Short note

There are nearly 31,000 HIV infected patients in Gabon. In Libreville, the capital, the prevalence is estimated at 7.7%. About 2627 tuberculosis patients, all types included, have been notified in 2001 to the World Health Organization of which 43% of smear positive new cases. The co-infection HIV-TB worsens the overall prognosis of our patients. The objective of our study is to determine the HIV seroprevalence among our tuberculosis patients. It is a cross-sectional study conducted between June 25th and August 31th 2001. All patients are new or relapse tuberculosis cases. There is no difference between the types of tuberculosis. The diagnosis was clinical, radiological and based on smear AFB sputum (according to the Ziehl Neelsen method). The patients agreed orally for HIV testing. We made two tests: a rapid one followed by Elisa if positive. 358 patients were examined among them 141 women and 217 men. The M/F sex ratio was 1.53 and the average age 32 years. Proportion of new patients reached 61%. Ninety seven per cent of patients suffered from a pulmonary tuberculosis, 58% smear positive and 26% were HIV-1 positive. According to this status, no statistical difference was notified towards sex, types of disease or patients and the smear sputum results.     

Hospitalizations for fungal infections after renal transplantation in the United States

Abstract: Fungal infections in renal transplant recipients have not been studied in a national population. Therefore, 33,420 renal transplant recipients in the United States Renal Data System from 1 July 1994 to 30 June 1997 were analyzed in a retrospective registry study of hospitalized fungal infections (FI). FI were most commonly associated with secondary diagnoses of esophagitis (68, 23.9%), pneumonia (57, 19.8%), meningitis (23, 7.6%), and urinary tract infection (29, 10.3%). Opportunistic organisms accounted for 95.4% of infections, led by candidiasis, aspergillosis, cryptococcosis, and zygomycosis. Most fungal infections (66%) had occurred by six months post-transplant, but only 22% by two months. In logistic regression analysis, end-stage renal disease due to diabetes, duration of pre-transplant dialysis, maintenance tacrolimus and allograft rejection were associated with FI. In Cox regression analysis, recipients with FI had a relative risk of mortality of 2.88 (95% CI=2.22–3.74) compared to all other recipients. Among FI, zygomycosis and aspergillosis were independently associated with both increased patient mortality and length of hospital stay. Most fungal infections in renal transplant recipients were opportunistic, occurred later than previously reported, and were associated with greatly decreased patient survival. Recipients with diabetes, prolonged pre-transplant dialysis, rejection, and tacrolimus immunosuppression should be considered high risk for FI.