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Biomedical subjects

P Weber

Publications and source records attributed to P Weber.

At least 289 records · Page 16Linked to original sources
PubMed1986

Effects of exposure to salty drinking water in an Arizona community. Cardiovascular mortality, hypertension prevalence, and relationships between blood pressure and sodium intake.

A high level of sodium (440 mg/L) in the water supply of Gila Bend, Ariz, caused concern because of apparently elevated rates of hypertension in Gila Bend Papago Indians. We surveyed 342 Gila Bend Papago Indians and 375 non-Indians from July to September 1983. Participants 25 years of age and older were interviewed for health risk factors, water consumption, and dietary sodium and calcium intake and had height, weight, blood pressure, and urinary sodium and potassium levels measured. No consistent associations were found between any of the sodium values and systolic or diastolic blood pressure. Mean blood pressures for the Gila Bend whites were lower in most age groups than in comparison US white populations. The prevalence rates of hypertension in Gila Bend were not significantly higher than national rates.

Adolescent↗
PubMed1985

Reticuloendothelial-depressing substance: studies on the mechanism of action.

This study was carried out to evaluate the mechanism of action of a reticuloendothelial (RE)-depressing substance. This RE-depressing substance was obtained from the plasma of dogs subjected to 3 hr of intestinal ischemia. RE-depressing substance was partially purified by dialysis and reverse-phase column chromatography. The assay of RE-depressing activity was based on the depression of the rate of clearance of colloidal carbon from the blood of rats or mice. The effect of RE-depressing substance on three other RE system (RES) test particles (gelatinized lipid emulsion, formalinized sheep erythrocytes, and IgM-coated erythrocytes) was determined. RE-depressing substance did not affect the clearance rate or the organ localization of these three test particles. Therefore, RE-depressing substance affected only the clearance of colloidal carbon. Since platelet aggregation has been shown to contribute to the clearance of colloidal carbon, the effect of RE-depressing substance on platelet aggregation was evaluated. RE-depressing substance depressed in vitro platelet aggregation induced by ADP or collagen. It was concluded that the effect of RE-depressing substance on the clearance of colloidal carbon was due to a depression of platelet aggregation rather than to a depression of hepatic macrophage phagocytic function.

Animals↗
PubMed1985

The human connection: the role of the nurse in organ donation.

Organ transplantation has greatly improved the grim outlook of patients suffering from end-stage organ failure. Unfortunately, many of these waiting patients will not realize their dream of being transplanted since the number of organ donors referred to transplant programs simply does not meet the need. This article describes the role the nurse can play in organ donation by discussing medical criteria needed to assess the donor, the determination of neurologic death, and guidelines to approaching families for consent.

Brain Death↗
PubMed1985

[Superoxide dismutase and catalase activity in HeLa 229 cells infected with Chlamydia trachomatis].

Cytosolic superoxide dismutase (SOD) activity was found to increase with time during HeLa cell culture, this increase being due exclusively to Mn-SOD. Infection of the cells by Chlamydia trachomatis resulted in a further enhancement of this Mn-SOD activity, whereas cytosolic catalase activity was decreased in these infected cells. Superoxide (O-2.) being able to induce Mn-SOD and to inhibit catalase, these data suggest that Chlamydia trachomatis infection could be responsible for an increase in O-2. production by the infected HeLa cells.

Catalase↗
PubMed1985

Electron microscope study on the developmental stages of Wuchereria bancrofti in the intermediate host: structure of the digestive tract.

The digestive tract and its development from undifferentiated primordia of first, second and third stage larvae of Wuchereria bancrofti are described at the ultrastructural level. In the young first stage larva the future oesophageal cells form a long column surrounding the cuticularized pharyngeal thread. In the midbody region, a small number of cells associated with the inner body represent the intestinal precursor. The large R-cells around the anal vesicle are fully differentiated.--The late first stage larva shows numerous, small oesophageal cells aligned around the pharyngeal thread. The few intestinal cells have greatly enlarged and start to form small lumina between their central membranes. The anal vesicle has increased and is divided in an inner and an outer portion.--In the second stage larva the oesephageal cells gradually differentiate into an inner muscular core around the triradiate cuticularized lumen, and an outer glandular sleeve. The intestinal cells start to form small microvilli at their luminal sides. Large amounts of particulate matter fill the lumina of oesophagus and intestine at this larval stage. The R-cells are still located between the posterior end of the intestine and the inner portion of the anal vesicle. Small, undifferentiated cells around the outer portion of the anal vesicle start to form the rectal tube.--The third stage larva has a fully differentiated digestive tract. The glandular portion of the oesophagus contains an abundance of secretory granules and vacuoles, the intestinal cells show lipid inclusions and long, tightly packed microvilli. The narrow rectal tube opens to the exterior.

Animals↗
PubMed1984

Isolation of sulfited oligosaccharides from glycoproteins treated with alkaline sulfite.

The oligosaccharide products resulting from treatment of mucin-type glycoproteins with alkali in the presence of the sulfite anion have been investigated. Treatment of fetuin and of tryptic glycopeptides from the human erythrocyte with this reagent resulted in the release of sulfited oligosaccharides identified as N-acetylsulfohexosamine (HexNAcSO3), alpha-NeuAc-(2----6)-HexNAcSO3, and alpha-NeuAc-(2----3)-Gal-(1----3 or 4)-[GlcNAc-(1----6)]-HexNAcSO3. In addition, 2.7 moles of sialic acid were released per mole of alpha-NeuAc-(2----6)-HexNAcSO3 from fetuin. The sulfohexosamine moiety is formed via unsaturated intermediates from a 3-O-substituted 2-acetamido-2-deoxy-D-galactosyl residue at the carbohydrate-peptide linkage site when this residue is not substituted at O-4 by another sugar residue. A reaction mechanism accounting for the release of the sulfited oligosaccharides from a 3-O- and 6-O-substituted hexosamine is proposed in which the oligosaccharide branch attached to O-6 is obtained as a specific fragment terminating in sulfohexosamine.

Animals↗
PubMed1984

Photobiology in space: an experiment on Spacelab I.

The joint European/US Spacelab Mission I, scheduled for October 1983 for a 9 day lasting Earth-orbiting flight, provides a laboratory system for various disciplines of science, including exobiology. On the pallet, in the experiment ES 029 "Microorganisms and Biomolecules in Space Hard Environment" 316 dry samples of Bacillus subtilis spores will be exposed to space vacuum and/or selected wavelenghs of solar UV radiation. After recovery action spectra of inactivation, mutation induction, reparability and photochemical damage in DNA and protein will be determined. The results will contribute to the understanding of the mechanism of the increased UV sensitivity of bacterial spores in vacuo and to a better assessment of the chance of survival of resistant life forms in space and of interplanetary transfer of life.

Bacillus subtilis↗
PubMed1984

Microorganisms and biomolecules in space environment experiment ES 029 on Spacelab-1.

Bacterial spores are proper test organisms for studying problems of space biology and exobiology. During the Spacelab 1 mission, studies on the limiting factors for survival of Bacillus subtilis spores in free space have been performed. An exposure tray on the pallet of Spacelab 1 accomodated 316 samples of dry spores for treatment with space vacuum and/or the following selected wavelengths of solar UV: > 170 nm, 220 nm, 240nm, 260nm and 280 nm. After recovery, inactivation, mutation induction, reparability, and photochemical damages in DNA and protein have been studied. The results contribute to the understanding of the mechanisms of increased UV sensitivity of bacterial spores in vacuo and to a better assessment of the chance of survival of resistant forms in space and of interplanetary transfer of life.

Atmospheric Pressure↗
PubMed1984

Chemical and biological evolution in space.

Astronomical infrared spectra are used to confirm the existence of complex organic molecules produced by ultraviolet photoprocessing of interstellar grain mantles. This material is shown to be the major component of the interstellar grains between the sun and the galactic center and, by inference, constitutes more than 10 million solar masses--or close to one part in a thousand of the entire mass of the milky way galaxy. It may be demonstrated that the primitive chemistry of the earth's surface was dominated by these extraterrestrial molecules after aggregated into comets if the rate of comet impacts with the earth was comparable with that required to account for the extinction of species over the past 300 million years. Ultraviolet irradiation of bacterial spores has been studied for the first time under simulated interstellar conditions. The inactivation time predicted for the less dense regions of space is at most several hundred years. Within molecular clouds it is shown on theoretical and experimental grounds that this time may be extended to tens of million of years which is the estimated time required for their transport from one solar system to another by a molecular cloud. However survival of spores during their initial exposure to the solar ultraviolet presents a problem for panspermia because it requires that in the process of ejection from the earth's surface they must be enclosed within a cocoon (or mantle) of ultraviolet absorbing material of approximately 0.6 micrometer thickness. Thus, although panspermia can not be rejected on the basis of lack of interstellar survival there may remain insurmountable obstacles to its occurring because of the very special protective shield requirements during ejection from its planetary source.

Bacillus subtilis↗
PubMed1984

Complications of extracapsular cataract surgery. The indications and risks of peripheral iridectomy.

With the increased popularity of extracapsular cataract surgery, the need for a peripheral iridectomy has been questioned. Some surgeons feel that the risks involved in performing the iridectomy are greater than when leaving the iris untouched. The indications and risks of iridectomy with cataract surgery are discussed. Four case reports are presented. In three cases, iridectomy was not performed with cataract surgery, and a pupillary block developed. In one of these three, a congenital cataract, secondary angle closure, developed requiring filtering surgery. In the fourth case, an iridectomy prevented serious complications from an unusual degree of postoperative inflammation with complete posterior synechia following uneventful cataract surgery.

Aged↗
PubMed1984

Electron microscope study on the developmental stages of Wuchereria bancrofti in the intermediate host: structure of the body wall.

The cuticle, hypodermis and musculature of first, second and third stage larvae of Wuchereria bancrofti from the mosquito vector were studied by transmission electron microscopy. The young first stage larva is characterized by a thick cuticle with distinct layers demonstrating oriented fibrils. The muscle cells are well developed while the hypodermis has undifferentiated cytoplasm. - The late first stage larva (sausage-stage) still has a thick cuticle but the fibrils are no longer discernible. The volume of the hypodermal cells increases considerably, their plasma shows an abundance of organelles. The muscle sectors are shifted apart from each other by the growth of the hypodermis. The muscle cells are small, they start to multiply. - The cuticle of the second stage larva consists of three thin laminae only. The number of the hypodermal cells increases. They form the characteristic hypodermal chords. The four muscle sectors contain poorly developed muscle cells which multiply until the onset of the second moult. - The third stage larva shows a thick, multilayered cuticle with fibrous sublayers. Hypodermis and musculature are well differentiated. The hypodermal chords protrude into the centre of the worm. The muscle cells have grown considerably and their outer fibrillar portions show beginning septation.

Animals↗
PubMed1984

Depression of left ventricular performance during canine splanchnic artery occlusion shock.

We studied canine left ventricular contractile performance following splanchnic artery occlusion (SAO) shock. We evaluated contractile performance by analyzing the left ventricular end systolic pressure-diameter relationship (sigma ES) because we have previously shown that sigma ES is independent of large changes in preload, afterload, and heart rate but sensitive to changes in ventricular contractility. Following release from 2 hours of SAO, seven dogs survived, five expired immediately, and ten expired between 0.5 and 3.5 hours (termed nonsurvivors, [NS]). The NS dogs exhibited slight tachycardia, slight increase in total peripheral resistance, marked decreases in +dP/dt, cardiac output, arterial blood pressure, stroke volume, and stroke work. Ventricular performance (sigma ES) declined with time following SAO release in the nonsurviving dogs; in contrast, surviving animals exhibited an augmentation of sigma ES during SAO and following SAO release. Sham dogs exhibited no time-dependent changes in sigma ES. The dogs that expired immediately following SAO release exhibited a precipitous decline in sigma ES from 43.0 +/- 9.0 to 23.0 +/- 4.8 mm Hg/mm within minutes of SAO release. We analyzed these data by Cox multiple regression analysis to determine the major covariates of survivability. The analysis revealed that sigma ES at the midpoint in time between SAO release and death was best correlated with the survival function. These results suggest that cardiovascular collapse of SAO shock is associated with an early and sustained loss of ventricular contractility.

Animals↗
PubMed1983

Neurotoxicity and protein binding of 2,5-hexanedione in the hen.

Previous studies in this laboratory have demonstrated 2,5-dimethylpyrrole adduct formation during in vitro exposure of protein amino groups to the neurotoxic n-hexane metabolite 2,5-hexanedione (2,5-HD). The present investigation reports in vivo pyrrole adduct formation in neural and nonneural protein from 2,5-HD-treated animals. Adult, White-Leghorn hens were given daily doses of either 200 or 70 mg 2,5-HD/kg, po, for up to 55 or 135 days, respectively. Additional animals were given 70 mg/kg for 63 days and then allowed to recover for 72 more days. Protein separation by gel electrophoresis followed by staining with a pyrrole-specific reagent yielded evidence of widespread adduct formation in protein from serum, liver, kidney, brain, and purified myelin. Binding was particularly strong in serum albumin nd myelin basic protein. Quantitation of the adduct in these tissues revealed that its formation reached peak levels at 20 days in high dose and 30 days in low-dose animals. Levels subsequently declined, suggesting the presence of a clearance mechanism capable of removing altered protein during continuing 2,5-HD exposure. Protein from animals on the recovery regimen contained no detectable pyrrole adduct. Pyrrole adduct formation was also detected in neurofilament protein preparations, although protein yields were too low to allow assessment of clearance. Hens at both dosages displayed clinical signs indicative of CNS and PNS neuropathy. Histologic findings included axonal swelling and degeneration in peripheral nerve and some spinal cord nerve tracts. A hypothesis is proposed involving differential clearance of pyrrole adduct from neural vs nonneural tissue to explain the mechanism of action and target organ specificity of 2,5-hexanedione.

Animals↗
PubMed1983

[Basilar thrombosis--an example of comprehensive rehabilitation of a 26-year-old female patient].

Medical elimination/reduction of a more or less acute functional disorder may be something considerably different from restoration to good health, or the ability to lead an independent life. The form this discrepancy may take; what it can mean to the patient, not least in terms of time consumed; which possibilities there are in view of a new beginning, a re-orientation; which ways and means there exist on the part of the patient as on that of the therapeutic personnel involved, or in the light of the legislative provisions; which role is played by society through the employer; how difficult it is to give a prognosis; these are the issues the authors intend to illustrate by describing the rehabilitation process a young woman of 26 years of age underwent following successful re-canalization of a previously thrombosed basilar artery by urokinetic fibrinolysis. It is also underlined that any rehabilitative measure taken should be oriented towards attainable goals, and be based on consultation (but not necessarily general agreement) among the rehabilitative team. This approach will help the patient comprehend the purpose of the measures taken, and serve to prevent hard feelings that may develop.

Adult↗