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Biomedical subjects

V Rowland

Publications and source records attributed to V Rowland.

13 recordsLinked to original sources
PubMed1988

Oral fluconazole therapy for patients with acquired immunodeficiency syndrome and cryptococcosis: experience with 22 patients.

PURPOSE: Cryptococcus neoformans causes infections in up to 10 percent of patients with the acquired immunodeficiency syndrome (AIDS). Nearly 50 percent of AIDS patients with previously treated cryptococcal meningitis will experience a relapse within six months. To reduce the likelihood of relapse, a maintenance regimen of amphotericin B is often administered weekly. However, the drug's intravenous route of administration and considerable toxicity have led to a search for alternative antifungal agents. In this report, we document our experience with fluconazole, a new oral triazole antifungal agent. PATIENTS AND METHODS: Twenty-two patients with AIDS and various forms of cryptococcosis were treated in an open-label study with 50 to 400 mg/day of fluconazole. The following laboratory studies were done on a monthly basis: complete blood cell count, liver function tests, serum creatinine level, serum cryptococcal antigen level, and serum fluconazole level. Lumbar puncture was performed in patients with meningitis every four to eight weeks to evaluate cerebrospinal fluid cryptococcal antigen, India ink preparation findings, fungal culture, fluconazole level, and protein, glucose, and cell count. RESULTS: Of seven patients with active culture-positive infections, four showed clinical and microbiologic responses (three of four with meningitis, one of three with extraneural cryptococcosis). Fifteen patients who had already undergone successful amphotericin B therapy for either meningitis (n = 14) or pneumonia (n = 1) received fluconazole as prophylaxis against relapse. Fourteen patients remained free of infection during 11 to 64 weeks of suppressive therapy; one patient with meningitis experienced relapse after 26 weeks of treatment. Reverse reactions were limited to increases in hepatic enzyme levels in four patients. CONCLUSION: These results appear sufficiently encouraging to warrant further trials of this oral agent in the suppression of chronic cryptococcosis and perhaps in the treatment of acute infection.

Acquired Immunodeficiency Syndrome↗
PubMed1987

A cross-referencing method for simultaneous slow and multiple unit potential recording with implanted electrodes.

The effective pairing of a non-polarizing Ag-AgCl with an adjacent polarizing stainless steel minielectrode for simultaneous recording of slow or sustained potentials, conventional ECoG, and multiple unit potentials is demonstrated. The two types of electrode reciprocate their reference functions, the non-polarizing electrode being insensitive to the low voltage 1500-2500 kHz signal transmitted by the polarizing member and the latter being insensitive to the slow potentials (0-0.5 Hz) detected by the non-polarizing member. The method enables obtaining unambiguous information from a localized source in bipolar derivations and permits use of construction methods simpler than those required for the hybrid electrodes formerly used.

Action Potentials↗
PubMed1985

Slow and multiple unit potentials in trace and temporal conditioning controlled by electrical reward in the rat.

Rats trained to expect medial forebrain bundle electrical reward every 17 sec acquire, in their visual cortex, a linear gradient of increasing negative potential over the prereinforcement half of the interval. The postreinforcement half of the interval is occupied by a less linear reversal of the negative shift. Integrated multiple unit activity from the same electrodes shows for the same half intervals, respectively, acquisition of progressive increase and sudden decrease. Behaviorally, naive subjects are most active following the reinforcement, becoming progressively less active in the second half of the interreinforcement interval. After training, the above pattern is reversed with sudden cessation of activity following reinforcement and progressive increase beginning about 5 sec later and continuing to the time of reinforcement. Slopes for the negative anticipatory potential gradient (APG) ranged from 8 to 28 microV/sec in different subjects on the 17 sec interreinforcement interval. Doubling the interval halved the slope, the maximum prereinforcement negative voltage remaining constant. The phenomenon thus appears as a relative or pacing dynamic rather than as an absolute or fixed microvolts/second function. Making the interreinforcement interval variable caused loss of both the anticipatory gradient and the integrated multiple unit increment. Trace conditioning with variable intertrial interval restored an anticipatory gradient and multiple unit increment. The specific dissociation of unit firing activity during the APG previously reported in the quietly expectant cat is not seen in this study owing to the excited expectancy in the rat anticipating MFB reward. Although the longer periods of negative potential gradient and unit action potential activity appear associated rather than dissociated, transient dissociations in patterns were observed during shorter duration shifts in the slow potential. Resolution of these variations must await more definitive study of unit activity and sustained potential genesis.

Action Potentials↗