Aging decreases vasoconstrictor responses of coronary resistance arterioles through endothelium-dependent mechanisms

OBJECTIVE: Aging decreases coronary blood flow and maximal reserve capacity. Impaired blood flow capacity may be related to an increased vasoconstrictor capacity of coronary resistance vessels. This study tested the hypothesis that aging increases the vasoconstrictor responsiveness of coronary arterioles isolated from myocardium of young (4 months) and old (24 months) Fischer 344 rats. METHODS: Isolated coronary arterioles were cannulated and pressurized (60 cm H2O) via hydrostatic pressure reservoirs. RESULTS: Contrary to our hypothesis, aging decreased responsiveness of coronary arterioles to endothelin (ET, 1 x 10(-11)-3 x 10(-8) M), potassium chloride (KCl, 10-100 mM), and pressure-induced myogenic responses (0-140 cm H2O). Removal of the endothelium from coronary arterioles increased vasoconstriction to all agonists; however, age-related KCl vasoconstrictor response differences remained, suggesting that K+ channel activity and/or the relative contribution of specific K+ channels to maintenance of vascular smooth muscle membrane potential may change with age. Removal of the endothelium, in addition to increasing responsiveness, eliminated aging-induced differences in ET- and pressure-induced vasoconstriction. L-NAME (10(-5)) incubation resulted in a greater enhancement of spontaneous tone in arterioles from old rats compared to those of young rats. ETB (BQ-788, 3 x 10(-8)) receptor blockade eliminated the age-associated differences. CONCLUSION: Collectively, these data suggest an age-associated increase in endothelial modulation of coronary resistance vessel constriction. This enhanced endothelial attenuation of coronary arteriolar constriction appears to result from increased basal release of nitric oxide. These alterations of coronary vascular reactivity may contribute to age-induced redistribution of coronary blood flow and diminished cardiac function.     

Molecular analysis of relapse in chronic myeloid leukemia after allogeneic bone marrow transplantation

Four patients with Philadelphia (Ph') positive chronic myeloid leukemia (CML) were studied before, after, and on relapse following allogeneic bone marrow transplantation (BMT). Southern analysis of DNA from cells collected before and at relapse after BMT was performed in order to investigate the origin of the leukemia at relapse. Using minisatellite probes we showed that the relapse occurred in cells of host origin in all four patients and this was confirmed with a Y chromosome specific probe in two male patients who had a female donor. Furthermore, using two probes for the breakpoint cluster region (bcr) on chromosome 22, we showed that leukemic cells at relapse bore identical rearrangements to those in the disease at time of presentation of each patient. We conclude that relapse in all four patients is due to re-emergence of the original leukemic clone.     

Placebo effect in burning mouth syndrome: a systematic review

Placebo controls play a critical role in the evaluation of any pharmacotherapy. This review surveys the placebo arm in 12 randomized controlled trials (RCTs) investigating burning mouth syndrome (BMS) and documents a positive placebo response in 6 of them. On average, treatment with placebos produced a response that was 72% as large as the response to active drugs. The lack of homogeneity in the use of placebos adds to the difficulty in comparing results and aggregating data. Future RCTs investigating BMS would benefit from larger sample sizes, adequate follow‐up periods, and use of a standard placebo.     

Opportunities with combined modality therapy for selective organ preservation in muscle-invasive bladder cancer

Combined-modality therapy for organ preservation represents an appropriate alternative to radical surgery in the management of several malignant diseases. The standard therapy for muscle-invasive bladder cancer in the United States has been radical cystectomy. Although the sequelae of radical surgery have been ameliorated somewhat by techniques for the construction of orthotopic bladders, the ideal therapy should both cure the patient of cancer and maintain a functioning natural bladder. Years of experience in Europe and Canada with bladder preservation using radiation therapy are documented. Advances in transurethral surgery technique and in the combination of radiation and chemotherapy have led to safe and effective regimens for patients with bladder cancer. Several recent trials with combined-modality therapy have established this treatment as a viable alternative to radical cystectomy in selected patients. © 1996 Wiley-Liss, Inc.     

Dermatitis during Spaceflight Associated with HSV-1 Reactivation

Human alpha herpesviruses herpes simplex virus (HSV-1) and varicella zoster virus (VZV) establish latency in various cranial nerve ganglia and often reactivate in response to stress-associated immune system dysregulation. Reactivation of Epstein Barr virus (EBV), VZV, HSV-1, and cytomegalovirus (CMV) is typically asymptomatic during spaceflight, though live/infectious virus has been recovered and the shedding rate increases with mission duration. The risk of clinical disease, therefore, may increase for astronauts assigned to extended missions (>180 days). Here, we report, for the first time, a case of HSV-1 skin rash (dermatitis) occurring during long-duration spaceflight. The astronaut reported persistent dermatitis during flight, which was treated onboard with oral antihistamines and topical/oral steroids. No HSV-1 DNA was detected in 6-month pre-mission saliva samples, but on flight day 82, a saliva and rash swab both yielded 4.8 copies/ng DNA and 5.3 × 10⁴ copies/ng DNA, respectively. Post-mission saliva samples continued to have a high infectious HSV-1 load (1.67 × 10⁷ copies/ng DNA). HSV-1 from both rash and saliva samples had 99.9% genotype homology. Additional physiological monitoring, including stress biomarkers (cortisol, dehydroepiandrosterone (DHEA), and salivary amylase), immune markers (adaptive regulatory and inflammatory plasma cytokines), and biochemical profile markers, including vitamin/mineral status and bone metabolism, are also presented for this case. These data highlight an atypical presentation of HSV-1 during spaceflight and underscore the importance of viral screening during clinical evaluations of in-flight dermatitis to determine viral etiology and guide treatment.     

Determination of molecular forms of brain acetylcholinesterase: Technical considerations

Sucrose density centrifugation has been used to characterize the relative levels of AChE molecular forms in different parts of the brain, during development, or in various disease states. We have examined the influence of various tissue or sample storage and handling techniques on the abundance of the 4S and 10S molecular forms of AChE in rat forebrain. Our results demonstrate that freezing either a subcellular fraction or the intact tissue causes dramatic shifts in the level of the 4S and 10S molecular forms as compared to the values obtained in fresh tissue. Total AChE activity was unchanged suggesting that 4S and 10S forms are equally active and that 4S AChE is easily dissociated from 10S. These observations suggest that 4S and 10S molecular forms in brain are extremely labile and that great care should be taken when studying the factors that regulate these forms.     

Antimicrobial Activities of Skincare Preparations from Plant Extracts

In this study, Tithonia diversifolia Helms. (A Gray), Aloe secundiflora (Miller) and Azadirachta indica (A. Juss) plant extracts were used to make herbal soaps while Thevetia peruviana (Schum) seed oil was used to make a herbal lotion for skincare. The soaps were tested for the growth inhibition of Escherichia coli, and Candida albicans. The lotion was evaluated against Staphylococcus aureus and E.coli. Although Tithonia diversifolia soap exhibited the highest inhibitory effect on the test bacterial strains, it had the least inhibition against C. albicans. Results from this study indicated that the ‘Tithonia diversifolia’ soap would have superior skin protection against the tested bacteria but would offer the least skin protection against C. albicans. The herbal lotion inhibited S. aureus and E. coli in a concentration dependent manner, however, the inhibitory effect was more pronounced on S. aureus.