Biochemical consequences of 5-fluorouracil gastrointestinal toxicity in rats; effect of high-dose uridine

Selective protection of the normal host tissues from the toxic effects of anticancer agents would allow the use of higher, probably more effective, doses of the drugs. It has been demonstrated that delayed high-dose uridine administration after 5-fluorouracil decreases the extent of myelosuppression and causes faster regeneration of the bone marrow. We studied the biochemical consequences of the gastrointestinal toxicity caused by 5-fluorouracil and the potential of high-dose uridine treatment to influence these adverse effects. 5-Fluorouracil caused dose-related decreases in the biochemical parameters (thymidine kinase, sucrase, maltase, alkaline phosphatase) selected as early markers of the impaired metabolic activity of the intestinal mucosa. The nadir of the biochemical changes was reached between 24 h and 72 h after 5-fluorouracil treatment, and complete regeneration of the mucosa took 6–7 days. Delayed high-dose uridine administration failed to mitigate the severity of the gastrointestinal damage that ensued after 5-fluorouracil treatment, but caused significantly earlier regeneration of the mucosa.     

Ritanserin in the treatment of alcohol dependence – a multi-center clinical trial

Four hundred and twenty-three alcohol dependent subjects were enrolled into a 12-week randomized, double-blind, placebo-controlled study to determine the safety and efficacy of the 5-HT₂ receptor antagonist, ritanserin (2.5 mg/day or 5 mg/day), in reducing alcohol intake and craving. All subjects received 1 week of single-blind placebo prior to randomization into the 11-week double-blind phase. Additionally, all subjects received weekly individual sessions of manual-guided cognitive-behavioral therapy. Comparing the single-blind period with endpoint, there was approximately a 23% reduction in drinks/day; 34% fall in the total number of drinking days/week; 22% decrease in drinks/drinking day; and a 37% diminution in alcohol craving for all treatment groups. All treatment groups experienced a beneficial clinical outcome as assessed by the Clinical Global Impression Scale. There was, however, no significant difference between treatment groups on any of these measures of alcohol drinking, craving, or clinical outcome. Subjects were of relatively high social functioning at baseline, and this did not change significantly during treatment. Treatment groups did not differ significantly on either medication compliance or reported adverse events. Ritanserin treatment was associated with a dose-related prolongation of subjects’ QTc interval recording on the electrocardiogram. These results suggest that alcohol dependent subjects can show marked clinical improvement within a structured alcohol treatment program. These findings do not support an important role for ritanserin in the treatment of alcohol dependence. Received: 30 April 1996/Final version: 3 July 1996     

Omeprazole: A Comprehensive Review

Omeprazole is a member of a new class of substituted benzimidazoles. These agents inhibit the proton pump in the gastric parietal cell, blocking the final step in the gastric acid secretory pathway. Omeprazole has been investigated for the treatment of gastric ulcer, duodenal ulcer, gastroesophageal reflux, and various hypersecretory states. The prolonged inhibition of gastric acid secretion allows for once-daily dosing in patients with peptic ulcer disease and gastroesophageal reflux, and once- or twice-daily dosing in patients with Zollinger-Ellison syndrome. Compared with currently available therapies, omeprazole is well tolerated and demonstrates a more rapid ulcer healing rate. It is superior to conventional therapies in the treatment of Zollinger-Ellison syndrome. Side effects are infrequent when the drug is used for the short-term management of ulcers.     

Examination of the effects of hemodynamic and pharmacologic interventions on coronary collateral flow in a patient during cardiac catheterization

The vasomotor response of native human collateral vessels to pharmacologic or hemodynamic vasodilatory stimuli is not well known. We describe a case where retrograde collateral flow velocity was measured both at baseline and following selected hemodynamic and pharmacologic interventions. This index case represents the first in a series of potential human physiologic studies designed to address questions pertaining to control of collateral blood supply in humans. © 1993 Wiley-Liss, Inc.     

Cardiovascular responses to various autonomic tests in males and females

The results of cardiovascular autonomic reflex tests on 224 healthy, randomly selected subjects were analysed to study possible sex differences in the autonomic responses. The heart rate response to the Valsalva manoeuvre (Valsalva ratio) was greater in females over 50 years than in males of the same age (1.58 ± 0.34 vs. 1.44 ± 0.30,p < 0.05). The heart rate response to deep breathing (E/I ratio) was higher in females under 50 years than in males under 50 years (1.37 ± 0.17 vs. 1.34 ± 0.18,p < 0.001). The diastolic blood pressure response to isometric handgrip was higher in males under 50 years than in females of the same age (p < 0.05). Although there were sex differences in the magnitude of the responses, the effect of age was similar in males and females and accelerated attenuation of the autonomic responses could not be demonstrated with increasing age. It can be concluded that significant sex differences exist in cardiovascular autonomic responses. The implication of such differences need consideration.     

Role of intracortical mechanisms in the late part of the silent period to transcranial stimulation of the human motor cortex

Transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (TES) of the human motor cortex produce a silent period (SP) following motor evoked potentials (MEPs). The early part of the SP can be explained by decreased alpha motor neuron excitability, whereas the late part is presumably due to suprasegmental mechanisms. In order to determine the level of the suprasegmental contribution to the generation of SPs, we recorded excitatory and inhibitory responses to TMS, TES, and percutaneous electrical brainstem stimulation (PBS) in the voluntarily activated first dorsal interosseous muscle of the hand. Stimulus intensities were set so that PBS and TES induced MEPs with areas equal to or larger than those of MEPs obtained with TMS. This procedure revealed that SPs were 49% and 83% shorter with TES and PBS, respectively, than with TMS. As TMS is more effective than TES or PBS in activating cortical interneurons, these findings support the idea that a significant component of the SP arises from intracortical mechanisms.     

Large granular lymphocyte expansions in patients with Felty's syndrome: analysis using anti-T cell receptor V beta-specific monoclonal antibodies.

Felty's syndrome (FS), the association of rheumatoid arthritis (RA) and idiopathic neutropenia, remains an unexplained phenomenon. HLA-DR4 is found in over 90% of cases. Patients with FS may have a T cell lymphocytosis of CD3+CD8+CD57+ large granular lymphocytes (LGL syndrome). In this study of 47 patients with FS, 19% had clear evidence for LGL expansions, while in total 42% had variable evidence for the LGL syndrome using currently available techniques. Of these T cell expansions, 76% were clonal, as demonstrated by Southern blotting and analysis with T cell receptor (TCR) beta chain constant region probes. This technique may fail to detect clonal populations in some patients. Cytofluorographic analysis using antibodies specific for TCR V beta chains identified patients with clonal LGL expansions with results comparable to those obtained with Southern blotting. No evidence for shared V beta usage among expansions from different patients was seen. The role of LGL in RA and FS is currently unclear, but this technique offers a practical and accessible means of identifying patients with LGL expansions, as a starting point for further investigation.     

Dorsal fracture of the hamate: distinctive radiographic appearance

Six patients who injured their wrists had radiographs documenting a dorsal, 5- to 10-mm oblong fragment of bone immediately proximal to the base of the fourth and/or fifth metacarpal bones. The fragment was seen on the pronation oblique and/or lateral projections, but not on the posteroanterior projection. The radiographic appearance of the fragment was remarkably similar in all cases. In the one patient in which it was performed, pluridirectional tomography demonstrated that the fragment originated from the dorsal surface of the hamate. Five of the six patients also had associated posterior dislocation of the fourth and/or fifth metacarpals. We conclude that this fragment represents a coronal fracture through the body of the hamate resulting from posterior dislocation or subluxation of the fourth and/or fifth metacarpal.     

Hormonal effects of high dose medroxyprogesterone acetate treatment in males with renal or prostatic adenocarcinoma

In 18 patients, 12 with renal and 6 with prostatic carcinoma, the gonadal, pituitary and adrenal functions were studied by measurements of steroid hormones and gonadotrophins, before and after six weeks treatment with medroxyprogesterone acetate (MPA), injected intramuscularly 500 mg per day for 5 days each week. The testosterone-oestradiol-binding globulin (TeBg) was measured and the amount of albumin and TeBg bound and unbound testosterone was calculated. Treatment with high doses of MPA caused a profound decrease in serum concentrations of testosterone, dehydroepiandrosterone sulphate (DHEAS), cortisol and TeBg. There were significant decreases in serum concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH) and oestradiol-17 beta. The serum concentration of prolactin was significantly elevated. The protein unbound testosterone fraction was lowered by MPA treatment but less than total testosterone. In conclusion, MPA therapy in high dose alters the gonadal, pituitary and adrenal functions suppressing serum concentrations of androgens, gonadotrophins, cortisol and TeBg but elevating prolactin concentration.     

Blood and plasma donations among a cohort of intravenous drug users

We evaluated the blood and plasma donation histories of a cohort of 2921 intravenous drug users in Baltimore, Md, and correlated these histories with their human immunodeficiency virus (HIV) serologic status, numbers of CD4 lymphocytes in the peripheral blood, and stigmata of intravenous drug use (scarred veins). Of the 793 intravenous drug users (27.1%) who had donated blood or plasma, 652 (82.2%) donated after they had started using intravenous drugs. Most subjects donated at commercial plasma centers, where they were paid $10 to $15 per donation. Although the HIV-1 seroprevalence of the entire cohort was 24.1%, the HIV-1 seroprevalence among those reporting plasma or blood donations declined progressively with time, from 17.1% in those who last donated in 1985 to 3.6% in those who last donated in 1988-1989. Many of the 437 intravenous drug users who had donated plasma or blood since 1985, when screening for HIV-1 was initiated, had not been notified and counseled about their HIV test results. Current programs to exclude individuals with a history of intravenous drug use from the plasma donor pool should be reevaluated and improved.