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Biomedical subjects

R Strauss

Publications and source records attributed to R Strauss.

At least 55 records · Page 3Linked to original sources
PubMed1995

Anomalous origin of right coronary artery from pulmonary artery.

A 67-year-old female was incidentally found to have an anomalous right coronary artery (RCA) arising from the pulmonary artery during evaluation of her aortic valve disease. The left main, left anterior descending, and circumflex coronary arteries were mildly dilated. Large collaterals from the left filled the RCA retrogradely. During surgery, a circumferential web was found at the ostia of the RCA. The patient underwent an aortic valve replacement, resection of the web, and translocation of the anomalous RCA into the aorta.

Aged↗
PubMed1993

[Effect of a filter system on measurement data and bacterial contamination in lung function studies].

80 measurements of the airway resistance of 20 patients did not yield any significant differences with or without using a bacterial filter (Pall PF 30) (p = 0.1213). Likewise, lung function tests conducted in 61 further patients did not reveal any relevant changes caused by introducing the filter, in respect of the lung function parameters VKin, FEV1, PEF, FEF25, FEF50, FEF75 and TLCO. In these studies the flow receptors were examined for contamination by bacteria. The introduction of the bacterial filter reduced the total count of identified germs from 108, 615 to 307, i.e. by 99.7 per cent, the greatest contamination being found in those parts that were close to the patient (57.6% with filter, 97.1% without filter). Germs of the resident flora of the mouth and pharynx were identified, and occasionally also potential infectious agents such as staphylococcus aureus and streptococcus pneumoniae. The use of a filter system results in a marked decrease in the exposition to germs in lung function tests, without exercising any adverse effect on the measurement data (cross-contamination risk: 0.00078%). This is also achieved--albeit to a lesser extent--by changing those parts of the flow receptor that are close to the patient (cross-contamination risk: 0.0841%). Hence, the use of a filter system appears particularly meaningful in patients with considerable immunodeficiency (advanced stages of HIV infection).

Airway Resistance↗
PubMed1993

A higher control center of locomotor behavior in the Drosophila brain.

In order to elucidate the behavioral significance of the central complex (CC), we have examined walking in 15 Drosophila mutant strains belonging to eight independent X-linked genes that affect the structure of the CC. Compared to four different wild-type strains, all are impaired either in a general or in a paradigm-dependent manner. Behavioral deficits concern walking activity, walking speed, or "straightness of walking" as measured in an object fixation task, in fast phototaxis, and in negative geotaxis. Behavioral deficits of three strains with mutations in different genes were studied in detail using mosaic analysis and high-speed cinematography. In all cases the focus for declining walking activity is located in the brain and is fully correlated with the respective defect of the CC. A high correlation between the degree of the behavioral impairment and the severity of the structural defect in two strains further adds to the evidence. Declining walking activity is not an unspecific side effect of structural brain defects, as steady walking is observed in structural mutants of the visual system and mushroom bodies. In mutant flies no-bridgeKS49 (nob), step size as a function of the stepping period is reduced. The focus of the resulting reduced average and maximum walking speeds resides in the brain and, again, the behavioral impairment fully correlates with the structural defects of the CC. While no indication is found for a role of the CC in setting up the basic stepping rhythm in straight walking (a respective phenotype in mutant central-complexKS181 flies resides in the ventral ganglion), a role in turning and start/stop maneuvers is suggested by aberrations in the stepping pattern of nob flies during such episodes.

Animals↗
PubMed1992

No-bridge of Drosophila melanogaster: portrait of a structural brain mutant of the central complex.

The mutant no-bridge (nobKS49) has its name from a structural defect in the protocerebral bridge of the central complex. This rod-shaped neuropil in nobKS49 has a large gap at the sagittal midplane, with some of the missing material accumulated more laterally. Mutant nob flies have a reduced maximal and average walking speed. Leg coordination is disturbed during turning but not while walking straight. Motivation for walking is low and steps are small due to slow forward swinging of the legs. Flies spontaneously may pass into an autistic (and possibly spastic) state in which they can move their legs and even perform cleaning movements but do not walk or fly. They spontaneously recover if left undisturbed. Gynandromorph experiments place the focus of the walking defects into the head. Mutant flies have a reduced tendency to escape when mechanically stimulated. In a brightly lit arena they do not avoid a black square above the horizon and they are negatively phototactic. In tethered flight optomotor responses are normal but the amplitude of spontaneous torque modulations as well as the number of torque spikes are reduced. If a single black bar is slowly rotated around the fly, the normal response pattern is observed. It vanishes, however, at moderately fast angular velocity at which the wild type still is fully responsible. The behavioral defects support the notion that the protocerebral bridge is part of a higher center for the regulation of behavior.

Animals↗
PubMed1991

Dietary carbohydrate, muscle glycogen, and power output during rowing training.

The belief that high-carbohydrate diets enhance training capacity (mean power output) has been extrapolated from studies that have varied dietary carbohydrate over a few days and measured muscle glycogen but did not assess power output during training. We hypothesized that a high-carbohydrate (HI) diet (10 g.kg body mass-1.day-1) would promote greater muscle glycogen content and greater mean power output during training than a moderate-carbohydrate (MOD) diet (5 g.kg body mass-1.day-1) over 4 wk of intense twice-daily rowing training. Dietary protein intake was 2 g.kg body mass-1.day-1, and fat intake was adjusted to maintain body mass. Twelve male and 10 female collegiate rowers were randomly assigned to the treatment groups. Training was 40 min at 70% peak O2 consumption (VO2) (A.M.) and either three 2,500-m time trials to assess power output or interval training at 70-90% peak VO2 (P.M.). Mean daily training was 65 min at 70% peak VO2 and 38 min at greater than or equal to 90% peak VO2. Mean muscle glycogen content increased 65% in the HI group (P less than 0.05) but remained constant at 119 mmol/kg in the MOD group over the 4 wk. Mean power output in time trials increased 10.7 and 1.6% after 4 wk in the HI and MOD groups, respectively (P less than 0.05). We conclude that a diet with 10 g carbohydrate.kg body mass-1.day-1 promotes greater muscle glycogen content and greater power output during training than a diet containing 5 g carbohydrate.kg body mass-1.day-1 over 4 wk of intense twice-daily rowing training.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Molecular mechanisms of radiation induced DNA damage: H-addition to bases, direct ionization and double strand break.

Structures and properties of G.(-H) and of TH. were obtained from quantum mechanical calculations. New AMBER parameters for these radicals were obtained to fit their structures and charge distributions. Molecular mechanics simulations of the conformational changes induced in a 12-mer of DNA, d(CGCGAATTCGCG), by these radicals show that the distances between the base and the C2' of the sugar becomes shorter. Such changes suggest that the base radical can abstract the H2' and transfer the radical from the base to the sugar. Once the radical becomes centered on the sugar a strand break can follow. A simultaneous formation of guanine and thymine radicals on opposite strands may lead to a double strand break.

Base Sequence↗
PubMed1990

Coordination of legs during straight walking and turning in Drosophila melanogaster.

Leg coordination of Drosophila melanogaster was studied using frame-by-frame film analysis. 1. For fastest walking alternating tripod coordination is observed which slightly deviates towards tetrapody as a function of step period. During acceleration or deceleration legs may transiently recover in diagonal pairs. 2. Mean step length increases with step frequency. 3. Mean recovery stroke duration increases with step period and plateaus beyond a period of about 110 ms. Middle legs recover significantly faster than others. 4. Ipsilateral footprints are transversally separated. 5. Walking is usually initiated in tripod coordination (frequently in combination with a turn), otherwise in an accelerating sequence which rapidly shifts towards tripod pattern. Flies can stop abruptly or decelerate over about one metachronal wave. 6. Short interruptions in walking are observed. Legs interrupted during swing phase stay lifted and finish recovery thereafter. 7. Slight changes in walking direction are obtained by altering step lengths only. Tight turns are composed of two or three phases with backward, zero and forward translatory components. In fast turning tripod coordination is maintained. Otherwise body sides can decouple widely. In all turns numbers of contralateral metachronal waves were equal. Results are compared to those for other walking insects and their relevance in screens for locomotor mutants is discussed.

Animals↗
PubMed1989

Technical considerations using a pulsed neodym-YAG laser for endoscopic shock wave lithotripsy.

First clinical experience with the use of a Q-switched pulsed Neodym-YAG Laser showed promising results. This paper focuses on two problems with respect to the optimal use of this laser: (1) is there any need for a special iron (Fe3+)-enriched irrigant, and (2) what is the best frequency for laser lithotripsy? To answer these questions, we used an in vitro model, measuring the laser-induced breakdown (LIB) photographically utilizing sodium chloride as an irrigant enriched with different amounts of Fe3+ ions. The disintegrative efficacy of the laser was tested utilizing a standard stone model (plaster cube) and working at different frequencies (1, 10, 40 Hz). The addition of Fe3+ ions resulted in significant improvement of LIB. However, in the presence of a test stone no difference between sodium chloride and Fe3+-enriched irrigants was noted. The use of lower frequencies (1, 10 Hz) lead to a remarkable improvement in the disintegrative efficacy of the laser compared to the standard frequencies (40, 50 Hz). For clinical use, addition of Fe3+ ions seems only necessary if optical breakdown (LIB) is insufficient despite the increase in generator voltage. In such a situation, we recommend the addition of an 1-ml Fe3+ solution to 10 liters of sodium chloride irrigant (= 0.5 mg Fe3+/dl). Moreover, the standard frequency for laser-induced intracorporeal lithotripsy should be 1-10 Hz.

Ferric Compounds↗
PubMed1989

Effects of regular physical training in a supervised class and additional intravenous prostaglandin E1 and naftidrofuryl infusion therapy in patients with intermittent claudication--a controlled study.

UNLABELLED: The aim of this study was to investigate if PGE1 i.v.-therapy after active physical training further increases the walking distance in PAOD stage IIb according to Fontaine. 48 outpatients with intermittent claudication underwent a standardized active walking training of about 6 months twice weekly. Afterwards patients were randomly given once daily an i.v. infusion of 60 micrograms PGE1 (3 ampoules prostavasin) or 600 mg naftidrofuryl. The therapy lasted for 3 weeks with the exception of Saturdays and Sundays. Besides laboratory and doppler parameters, painfree and maximum walking distance (treadmill, 10% incline, 3.5 km/h) were determined. RESULTS: Under active physical training the patients' walking distance increased significantly to more than double the baseline levels. Further significant increase of the painfree walking distance was seen after a 3 week treatment with PGE1 from 136 to 270 m (99%) as well as with naftidrofuryl from 117 to 230 m (97%). While this difference was not significant there was a significant difference in favour to PGE1 after the follow-up period (p less than 0.01). In the PGE1-group the painfree walking distance showed a further increase (from 270m to 306m) whereas it decreased in the naftidrofuryl-group (from 230m to 210m). At the same time under PGE1 the ankle/arm index increased significantly in comparison to naftidrofuryl (p less than 0.01). Side effects differed significantly in respect of the frequency and severity. In the PGE1-group in 20.8% of the patients side effects occurred, whereas in 91.6% of the patients in the naftidrofuryl-group side effects were observed. In no case therapy had to be discontinued because of side effects.

Aged↗
PubMed1989

Low rejection rate when using unrelated or haploidentical donors for children with leukemia undergoing marrow transplantation.

Thirty-nine children with leukemia were entered into a bone marrow transplantation study comparing the use of unrelated donors who were HLA-Dr identical and matched at least with three of the four HLA-A or B loci, with haploidentical related donors. Although marrows were prepared by T lymphocyte depletion in vitro, the rejection rate of marrow in these patients was only 13% (5/39). Four patients had early rejections, and three of these four had autologous recovery immediately without evidence of leukemic recurrence. The fifth had a delayed rejection occurring approximately 2 1/2 months after transplant. These results were achievable by an ablative regimen incorporating increased immunosuppression. Although the small sample size does not yet permit evaluation of outcome comparing one donor type versus another, the early findings document a high rate of successful engraftment.

Adolescent↗
PubMed1988

Coagulation changes during packed red cell replacement of major blood loss.

A greater proportion of blood replacement needs are being met by packed red cell concentrates rather than whole blood in situations of major blood loss. Twelve patients, who required major blood replacement during elective surgery, were studied to determine the changes in coagulation when packed red cells were used to replace major blood loss. In addition, the coagulation abnormalities present at the time an observer noted excessive bleeding were determined. Prior to blood product replacement and after the estimated loss of each 0.3 blood volume, coagulation tests were obtained including prothrombin time (PT), partial thromboplastin time (aPTT), platelet count, thrombin time (TT), fibrinogen levels, and assays of coagulation Factors V, VIII, and IX. Coagulation tests were repeated when clinical hemostasis was judged inadequate by the anesthesiologist and attending surgeon. Significant decreases in platelet count, fibrinogen levels, and Factor V, VIII, and IX levels occurred as increasing blood volumes were replaced. Increases in PT and aPTT above control occurred in nine of the 12 patients prior to replacement of 1 blood volume; none of the nine patients had increased clinical bleeding. In four of seven patients who had blood replacement of greater than 1 blood volume, increased clinical bleeding was noted by the observer. Platelet counts were less than 100,000/mm3 in each of these four patients, and a platelet concentrate obtained by pheresis of a single donor was administered. In two of the four patients platelet counts increased, but clinical bleeding did not resolve.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Coagulation↗
PubMed1988

Simple microbiologic detection of Campylobacter pylori.

A study of 84 gastric biopsies taken from 42 adult patients revealed simple techniques for Gram stain and culture for Campylobacter pylori. In an initial study of 18 biopsies, Gram stains prepared from ground, diluted tissue were all negative for curved, gram-negative rods, whereas 13 of these specimens were positive for C. pylori by culture. The Gram stains for the remaining 66 biopsies were prepared by a rinse-imprint technique. In this group, there were 30 Gram stains positive for organisms resembling C. pylori and 32 positive cultures. By Gram-staining two sites, fundus and antrum, the sensitivity of the Gram stain for identifying a positive specimen increased from 91 to 100%. Gram stain may be the preferred technique for rapid diagnosis. When cultured, C. pylori was recovered most often on modified Thayer-Martin medium incubated microaerophilically at 35 degrees C. The presence of antibiotics in modified Thayer-Martin medium limited upper respiratory flora overgrowth, which was often present on nonselective media.

Biopsy↗
PubMed1986

Enalaprilat in hypertensive emergencies.

Enalaprilat (MK-422), an intravenously administered angiotensin-converting enzyme inhibitor, which is the parent compound of the oral angiotensin-converting enzyme inhibitor enalapril (MK-421), was studied in 11 patients with asymptomatic accelerated hypertension. Each patient received an initial intravenous dose of 1 mg, followed at one-hour intervals by enalaprilat 10 mg, furosemide 40 mg, and enalaprilat 40 mg. Six of 11 patients responded with a drop in mean arterial pressure greater than 15 mm Hg to diastolic levels below 110 mm Hg; there were four partial responders and one nonresponder. Pretreatment renins were not predictive of blood pressure response. No patient had any adverse reaction to the drug; there were no significant changes in posttreatment laboratory values. We conclude that enalaprilat is an effective, well-tolerated agent for the treatment of uncomplicated accelerated hypertension and its use does not imperil nonresponding uncomplicated patients.

Adult↗
PubMed1985

Successful administration of metoclopramide for the treatment of nausea in patients with advanced liver disease. A double-blind controlled trial.

A double-blind comparison of metoclopramide versus placebo was performed on 8 cirrhotic patients with nausea (8 cases) and heartburn (3 of the 8 cases) plus mild portal-systemic encephalopathy. As metoclopramide is a dopamine antagonist and dopamine-inadequate neurotransmission has been implicated in the pathogenesis of hepatic coma, this study was also designed to evaluate the effects of metoclopramide on mental state. The study included basal, placebo, metoclopramide, and final periods; each period lasted for 2 wk. Throughout the study patients received 3 g/day of neomycin and an 1800-cal diet containing 40 g/day of mixed protein. During the placebo and metoclopramide phases patients received either two 10-mg metoclopramide capsules t.i.d. or identical placebo capsules. During the study, biweekly liver function tests and portal-systemic encephalopathy parameters were evaluated. A self-evaluation for the presence of nausea and heartburn was also obtained. To monitor the dopamine-blockade effect of metoclopramide, serum prolactin levels were measured. Metoclopramide significantly suppressed the subjective signs of nausea (7 of 8 cases) and heartburn (all cases). Serum prolactin levels were 22 +/- 21 ng/ml, 30 +/- 31 ng/ml, 110 +/- 57 ng/ml (p less than 0.01), and 18.6 +/- 2 ng/ml during basal, placebo, metoclopramide, and final periods, respectively. In spite of these signs of dopamine blockade, no deterioration in mental state, asterixis, electroencephalograms, blood ammonia levels, or psychometric testings were observed. In addition, no extrapyramidal signs were noticeable during any period of the study. One patient presented transient somnolence at the end of the metoclopramide period. We conclude that dopamine blockade is not associated with the appearance of portal-systemic encephalopathy. Metoclopramide is a safe and effective treatment for nausea and heartburn in patients with advanced liver disease.

Chronic Disease↗
PubMed1985

Effects of cyclosporin A on experimental infection with Listeria monocytogenes.

The effects of cyclosporin A on primary and secondary infection of mice with Listeria monocytogenes was studied both at the microbiological and the histomorphological level. This drug, when given in a dose of 100 mg/kg/day, was found to inhibit the development of protective immunity after primary infection as well as the expression of acquired immunity to challenge infection as determined by counting of bacterial numbers in the spleen. The manifestation of delayed type hypersensitivity was also impaired. When the cellular immune system was functionally intact, the formation of granulomas composed of macrophages and lymphocytes enabled the animals to overcome the Listeria infection. In mice treated with cyclosporin A protective granulomatous reaction during secondary infection did not occur. Instead numerous necropurulent lesions developed in the reticuloendothelial organs, such as spleen and liver, of animals unable to control the lethal infection.

Animals↗