Temporary leukocyte depletion reduces ventricular dysfunction during prolonged postischemic reperfusion

Leukocyte depletion improves early postischemic ventricular performance in neonatal models of global myocardial ischemia. However, the rate of leukocyte reaccumulation after cardiopulmonary bypass and its subsequent impact on myocardial function is not known. This laboratory study examined the effect of leukocyte depletion on myocardial performance during the initial 6-hour period after bypass in an in situ, in vivo porcine model of neonatal cardiac surgery. Fifteen 3- to 5-day-old piglets (eight control and seven leukocyte depleted animals) were instrumented by placement of left ventricular short-axis sonomicrometry crystals and an intraventricular micromanometer catheter. Mechanical leukocyte depletion was achieved with Pall RC100 filters (Pall Biomedical, Inc., Fajardo, Puerto Rico) in the cardiopulmonary bypass circuit. Neonatal hearts were subjected to 90 minutes of hypothermic ischemia after a single dose of cold crystalloid cardioplegia. Two control animals died after the operation and were excluded from data analysis. Leukocyte filtration reduced the granulocyte count during initial myocardial reperfusion to 0.8% of control values. However, circulating granulocyte counts increased in leukocyte depleted animals throughout the postoperative period, reaching 68% of control values by 6 hours. Despite this rapid return of circulating granulocytes, animals subjected to leukocyte depletion had significantly better preservation of left ventricular performance (measured by preload recruitable stroke work, p < or = 0.02), left ventricular systolic function (measured by end-systolic pressure-volume relationship, p < or = 0.05), and ventricular compliance (p < or = 0.04) during the experiment. These changes in ventricular function were associated with a significant increase in left ventricular water content (p < or = 0.02) and tissue myeloperoxidase activity (p < or = 0.005) in control animals compared with leukocyte depleted animals. This study demonstrates that leukocyte depletion during initial reperfusion results in sustained improvement in postischemic left ventricular function despite the rapid return of granulocytes to the circulation.     

Long-term efficacy of cyclical etidronate therapy in postmenopausal osteoporosis

Sixty-two women (mean age 68.7 +/- 0.9 yr) with postmenopausal spinal osteoporosis were treated with cyclical etidronate therapy (400 mg for 2 weeks alternating with 12 weeks of 1 gm elemental calcium and 400 IU Vitamin D3) for a minimum of 2 yr. Bone mineral density (BMD) of the lumbar spine (g/cm2) increased significantly (p < 0.0001) after yr 1 (4.1 +/- 0.5 per cent) and yr 2 compared with yr 1 (2.2 +/- 0.5 per cent). The response rate was 89 per cent after yr 1 and 84 per cent after yr 2. BMD of the hip (30 patients) increased by 1.5 +/- 0.9 per cent after yr 1 and 5.5 +/- 1.1 per cent (p < 0.0001) after yr 2 when compared with baseline. The response rate was 63 per cent after yr 1 and 80 per cent after yr 2. Smaller numbers of patients continued with treatment up to 4 yr with no adverse long-term effects.     

Dopamine and the regulation of cell proliferation in gerbil (Meriones unguiculatus) pyloric mucosa

The epithelium of the digestive system mucosa consists of a highly dynamic cell population. The conditions under which mitotic activity in the gastrointestinal epithelium is regulated is as yet poorly understood. Nevertheless, it is assumed that some biogenic amines might be involved. Having demonstrated that dopaminergic cells occur in the stomach of gerbils (Meriones unguiculatus), in the present study we examined the influence of dopamine antagonist haloperidol on the proliferation of epithelial cells in the mucosa of the stomach. Proliferating cells were detected immunocytochemically and quantified after in-vivo labeling with 5-bromo-2'-desoxyuridine in both haloperidol- and saline-treated animals. The results show that acute doses of haloperidol significantly increases the proliferation rate in the pyloric mucosa, suggesting that dopamine plays a probable modulatory role in the regulation of mitotic activity. These findings are discussed with regard to the role of paraneurons in regulating epithelial mitosis.     

Chances of cure are not compromised with sphincter-saving procedures for cancer of the lower third of the rectum

BACKGROUND: The goal of this study was to compare patterns of recurrence and long-term outcome after sphincter-saving procedures (SSPs) and abdominoperineal resection (APR) in patients with tumors located in the lower third of the rectum. METHODS: We reviewed the charts of 1001 patients operated on for primary rectal adenocarcinoma between 1980 and 1991. All patients with tumors located between 5 and 7 cm from the anal verge and treated with curative intent were included. RESULTS: Of the 261 patients who met our criteria, 162 had undergone SSP and 99 had undergone APR. The local recurrence rates for SSP and APR were 8% and 11%, respectively (p = 0.41), and the distant metastases rates were 23% and 28%, respectively (p = 0.35). Recurrence and distant metastases rates for SSP and APR, respectively, did not differ by TNM classification: state I, 10% versus 9% (p = 0.9); stage II, 25% versus 43% (p = 0.13); and stage III, 56% versus 57% (p = 0.92). Five-year disease-free survival rates for SSP and APR patients were 70.5% and 62.3%, respectively (p = 0.2). CONCLUSIONS: Tumors in the lower third of the rectum can be treated with sphincter-saving procedures without compromising the chance of cure.     

On parity problems and the functional-link artificial neural network

This paper contains the proof of a theorem on the capability of functional-link artificial neural networks both to represent and to learn the n-dimensional parity problem. The result is obtained by an embedding of the problem into a space of dimension 2ⁿ — 1. It is shown that the Volterra expansion of the data in n-dimensions provides the necessary transformation. By computing the parity function, it is shown that a suitable set of neural network weights can be deduced. Finally, it is demonstrated that 2ⁿ — 1 is the minimum embedding dimension for the problem.The contribution of A Zuderell of the University of Innsbruck is acknowledged.     

Long-wavelength infrared photoinduced switching of a resonanttunneling diode using the intersubband transition

Voltage switching induced by long-wavelength infrared light from a CO₂ laser was observed using a double-barrier resonant tunneling diode (RTD) biased in the bistable region and the intersubband transition (IT) between the quantum confined states. Possible optoelectronic and all-optical switching applications involving hysteresis are proposed and discussed     

Specific heat of thin helium films in a cylindrical geometry

We report measurements of the specific heat of thin helium films adsorbed in the 0.2 µm pores of Anopore membranes. Over the temperature range of these studies, two specific heat anomalies, strongly dependent on helium film thickness, were found.     

A comparative cerebral blood flow study in a baboon model with acetazolamide provocation: 99mTc-HMPAO vs 123I(IMP)

Pharmacological interactions are important when nuclear medical procedures are applied to patients under drug therapy, or drug provocation. This study compares in baboon models (regional) cerebral blood flow [(r)CBF] results from 99mTc-HMPAO and 123I-iodoamphetamine [123I(IMP)] each with and without acetazolamide, the latter a suggested drug for testing cerebrovascular reserve. Expected differences in cerebral uptake were observed between the two radio-tracers without acetazolamide. The increase in tracer uptake resulting from acetazolamide is significantly enhanced for 123I(IMP), which could have diagnostic implications.     

Vitamin D and calcium in the prevention of corticosteroid induced osteoporosis: a 3 year followup

OBJECTIVE: To determine the efficacy and safety of vitamin D 50,000 units/week and calcium 1,000 mg/day in the prevention of corticosteroid induced osteoporosis. METHODS: A minimized double blind, placebo controlled trial in corticosteroid treated subjects in a tertiary care university affiliated hospital. The sample was 62 subjects with polymyalgia rheumatica, temporal arteritis, asthma, vasculitis, or systemic lupus erythematosus. The primary outcome measure was the percentage change in bone mineral density (BMD) of the lumbar spine in the 2 treatment groups from baseline to 36 mo followup. RESULTS: BMD of the lumbar spine in the vitamin D and calcium treated group decreased by a mean (SD) of 2.6% (4.1%) at 12 mo, 3.7% (4.5%) at 24 mo, and 2.2% (5.8%) at 36 mo. In the placebo group there was a decrease of 4.1% (4.1%) at 12 mo, 3.8% (5.6%) at 24 mo, and 1.5% (8.8%) at 36 mo. The observed differences between groups were not statistically significant. The difference at 36 mo was-0.693% (95% CI -5.34, 3.95). CONCLUSION: Vitamin D and calcium may help prevent the early loss of bone seen in the lumbar spine as measured by densitometry of the lumbar spine. Longterm vitamin D and calcium in those undergoing extended therapy with corticosteroids does not appear to be beneficial.