Intestinal absorption of water and electrolytes.

1. Recent advances in knowledge of intestinal physiology have provided some insight into disturbed mechanisms and their clinical effects; for example, diarrhoea can now be defined biochemically as excessive fluid and electrolyte loss due to their malabsorption or excessive secretion. 2. Because of differences in structure and in absorptive and secretory mechanisms, the various parts of the gut perform different functions. In the jejunum, transport activity is extensive and the rapid equilibration of its content provides the optimal absorptive mixture. Functionally, the ileum and colon are similar; compared with the jejunum, they have greater absorptive capacity for electrolytes and generate significantly higher transmural electrical potentials. In the colon, some transport mechanisms are potentiated by adrenocortical steroids. 3. Water and electrolyte absorption and secretion are the end-products of bidirectional fluxes across the intestinal wall that are several times greater than net movement in either direction. Secretion is the surplus of negative flux (into the lumen) and absorption the surplus of positive flux (out of it). 4. Many electrolyte transport mechanisms require the absorption of other electrolytes or non-electrolytes, and some are concerned with electrolyte exchange. Water transport is always passive, in the direction of solute flow, but its solvent drag can move solutes across the intestinal membrane.     

Criteria for Emergency Brain MRI During Stroke-Alert

ObjectivesIntravenous (IV) tissue plasminogen activator (tPA) should be given to patients with acute ischemic stroke (AIS) and avoided in stroke mimics (SM). Select use of emergency brain magnetic resonance imaging (eMRI-brain) in stroke-alerts aids diagnosis, but accepted utilization criteria for eMRI-brain do not currently exist. We developed criteria for eMRI-brain and report the yield of eMRI-brain in stroke-alert patients.Materials and MethodsWe developed three history-based criteria for performing eMRI-brain during stroke-alerts: (1) history of previous similar deficits, (2) change in consciousness at onset of symptoms, (3) symptom presentation consistent with migraine aura. We then performed a retrospective chart review of patients who presented as a stroke-alert over a 5-year period and determined how these criteria affected administration of IV tPA to AIS and SM patients.ResultsAmong 3,512 stroke-alerts, 230 (8.1%) patients met our criteria for eMRI-brain exams: 217 (92.6%) had SM and 17 (7.4%) had AIS. Our IV tPA decision-making analysis showed that based on eMRI-brain IV tPA was less frequently administered to SM patients (PCC-0.841, p=0.036) with less failures to administer IV tPA to patients with AIS (PCC -0.907, p-value=0.013, Pearson correlation coefficient). No patients became ineligible for IV tPA due to MRI-related time delays.ConclusionsOur history based criteria for performing eMRI-brain during stroke-alerts show a high yield of stroke mimics. Selective eMRI-brain improves decision-making accuracy regarding IV tPA administration.     

Lipid Composition in Rats with Nonischemic Chronic Heart Failure

The initial stages of nonischemic chronic heart failure in rats (model of oleothorax) were accompanied by the development of dyslipidemia. This state was characterized by an increase in total cholesterol concentration (due to the fraction of low-density lipoproteins) and atherogenicity index. The concentrations of plasma total cholesterol and low-density lipoproteins were shown to decrease in animals with severe course of nonischemic chronic heart failure. These changes were accompanied by a decrease in the atherogenicity index. Intragastric administration of cholesterol had little effect on the lipid composition of blood plasma in rats, irrespective of the severity of heart failure.     

Glutamic acid in treatment of alcohol intoxication aggravated by ecologically unfavorable factors

Alcohol intoxication aggravated by exposure to ecologically unfavorable factors (methanol and furfural vapors) induced pronounced desynchronization of hematologic processes, dramatic disturbance of carbohydrate metabolism, and considerable structural changes in internal organs. Treatment with glutamic acid reduced pathological manifestations and increased the adaptive capacities of the organism. Functional and morphological changes observed in laboratory animals after treatment with the neurometabolic compound glutamic acid could be classified as reversible. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 3, pp. 321–325, March, 2000     

An amplifying screen-film combination for mammography

Moscow Scientific-Research Institute for Diagnosis and Surgery. Institute of Chemical Physics, Russian Academy of Sciences, Moscow. Kazan' Scientific-Research Institute Tekhfotoproekt. Translated from Meditsinskaya Tekhnika, No. 6, p. 6, November–December, 1992.     

Influence of polarization filtration on the information readout from pulsating blood vessels

Imaging photoplethysmography (IPPG) is a recently developed technique for noncontact assessment of cardiovascular function. However, its wide use is limited by low signal-to-noise ratio due to motion artifacts. The aim of this work is to estimate the polarization-filtration impact on discriminating artifacts in IPPG measurements. Experiments were carried out in-vivo by almost simultaneous illumination of subject’s palm with polarized and non-polarized light during video recording of 41 subjects. It was found that the light-polarization filtration efficiently reduces motion artifacts compared to the non-polarized illumination while the pulsation amplitude measured at the heartbeat frequency remains unaffected. The polarization filtration improves reliability of IPPG system in non-contact monitoring of subject’s heart rate and its variability.OCIS codes: (170.0170) Medical optics and biotechnology, (170.3880) Medical and biological imaging, (280.0280) Remote sensing and sensors, (170.3660) Light propagation in tissues