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Biomedical subjects

R Schuster

Publications and source records attributed to R Schuster.

At least 73 records · Page 4Linked to original sources
PubMed1993

Distribution, propagation, and coordination of contractile activity in lymphatics.

The propagation and coordination of lymphatic contractions were studied in the mesentery of the rat small intestine using in situ microscopic observation. Indexes of lymphatic diameter were simultaneously measured at two adjacent lymphangions in spontaneously contracting lymphatics (n = 51). Diameter index, contraction frequency, and the percentage of the intersegmental contractions that were propagated and coordinated (PP) were determined at both sites. The conduction velocity of the contractile activity and the percentage of the coordinated contractions that were propagated both antegrade to the direction of lymph flow and retrograde to the flow stream were determined. The results indicate that 1) 80-90% of the lymphatic contractions in the vessels we evaluated were propagated, 2) the wave of contractile activity propagated both centrally and peripherally, and 3) the conduction velocity of the contractile activity was approximately 4-8 mm/s. We tested the hypothesis that gap junctional communication is responsible for the coordination of the contractile event. To accomplish this, we used the gap junction blockers n-heptanol and oleic acid. PP was 90 +/- 4% under normal conditions and fell to a minimum value of 55 +/- 7% during the gap junction blockade. These results indicate that gap junctional communication played an important role in the propagation and coordination of contractions that occurred in spontaneously active lymphatics.

Alcohols↗
PubMed1993

[Prospective study of determining the value of D-dimer in diagnosing pulmonary embolism].

Pulmonary embolism (PE) is still misdiagnosed in a high proportion of cases. 107 patients admitted for suspected pulmonary embolism were studied prospectively to shed light on the value of ELISA-D-dimer and Latex-D-dimer. Pulmonary embolism was ruled out by negative perfusion scans in 66 patients (61.7%) and by angiography in 24 patients. 58% of the scans suggesting a high probability of PE were confirmed by angiography, but only 18% of the scans suggesting a low or intermediate probability of PE. Sensitivity and specificity were 88% and 79%, respectively for the D-dimer ELISA, versus 94% and 90% for the Latex agglutination test. The Latex test increased the positive predictive value of lung scanning suggesting low to intermediate probability of PE (group B) from 18% to 75% and that of lung scanning suggesting high probability of PE (group C) from 58% to 93%. The positive predictive value was improved by ELISA-D-dimer in both groups to 75%. In order to augment the diagnostic efficacy in clinical practice the determination of Latex-D-dimer simultaneously with lung scanning is recommended.

Adult↗
PubMed1993

Cooperative social coordination and aggression: II. Effects of sex and housing among three strains of intact laboratory rats differing in aggressiveness.

Pairs of laboratory rats were rewarded with sugar solution for cooperating by means of synchronized shuttling in a rectangular chamber. Learning and performance were compared in males and females of three strains--S3, Charles River, and Wistar--ordered in terms of decreasing levels of aggressiveness. In addition, same-sex pairs of each strain were housed either together or individually. When housed together, males and females of all strains eventually cooperated at comparable levels, with rates of acquisition across strains inversely related to their aggressiveness. Individual housing, in contrast, was associated with severe deficits in males of the S3 and CR strains linked to violent fighting and prolonged freezing by animals who had previously been defeated. All other individually housed groups, including males of the Wistar strain and females of all strains, were able to cooperate, including S3 females whose violent fighting was not associated with immobility by defeated animals. In general, the majority of groups were able to cooperate despite differences in aggressiveness associated with sex, strain, and housing. Possible processes in this accommodation are discussed.

Aggression↗
PubMed1993

[Risk for humans and animals by excretion of helminth eggs].

In presence of large human and animal populations on a small area potential danger is given for frequent occurrence of helminth infections. Important helminthosis of men and animals in Middle Europe are represented, particularly the correlations between hosts and parasitic agents in epidemiological point of view. The represented helminth species are such of man as final host which are dangerous for men and animals, and such of animals which are dangerous also for both man and animals. On the one hand there is a lot of new scientific findings, on the other hand there are gaps in knowledge, concerning species of nematodes, cestodes and trematodes with reference to living expectancy, reproduction potential, duration and dynamic of elimination as well as resistance of exogenous helminth stages and finally methods for proof of pathogens in the biotope as a requirement for purposeful control with ecologically acceptance.

Animals↗
PubMed1993

[Contributions to the parasite fauna of local hosts. 10. On the endoparasitic fauna of Felis silvestris].

The investigations based on examination of the internal organs of 25 wild cats of the Harz population died from different causes in the period from 1982 to 1989. 22 animals (= 88%) were positive for parasites. The following species were found: Hydatigera taeniaeformis, Taenia crassiceps, T. martis larv. (spurious parasite), Mesocestoides litteratus, Capillaria plica, Capillaria sp. (aerophila?), Toxocara mystax, Cystoisopora felis. Toxocara mystax and Hydatigera taeniaeformis were the most often diagnosed helminths. Their number ranged up to 247 and 30 specimen respectively. The stated parasite fauna is comparable with findings in run wild domestic cats in rural areas. Voles contained in the stomach content of most of the cats play a role in the epizootiology of wild cat endoparasites.

Animals↗
PubMed1993

[A case of an Oslerus osleri infection (nematoda) in a dog].

Nodules had been found in the mucous membrane of trachea and bronchiae of an 8 month old male miniature poodle suffering from dyspnoea. Besides worm fragments one female and one male nematode as well as a number of nematode eggs and larvae were discovered by parasitological examination of tracheal rinse liquid. They could be identified as Oslerus osleri. A literature survey is given on peculiarities in the life cycle, on the epidemiology, the clinical signs, the diagnostic and the treatment of this helminthosis rarely diagnosed in Europe.

Animals↗
PubMed1993

[Compliance of children with bronchial asthma in long-term therapy with theophylline retard preparations].

427 samples of the saliva of 235 children were taken on an outpatient basis to follow up long-term theophylline treatment. 37 samples from 34 children did not reveal the presence of any theophylline. The absolute non-compliance found in this manner is 21% in the 9 to 12 years age bracket and significantly higher than with the children below 9 years and above 14 years of age (8 and 10%, respectively). Better differentiation of compliance and separation from underdosing was achieved in 38 children by comparing the outpatient-controlled theophylline levels with the values obtained on an inpatient basis. For 10 patients this method definitely revealed non-compliance, whereas compliance was doubtful with 12 children and 15 children had strictly adhered to the prescribed dosage regimen. To improve the intake discipline the theophylline levels should be regularly followed up under outpatient conditions and evaluated in cooperation with the patients.

Adolescent↗
PubMed1993

[Oral ciprofloxacin therapy in juvenile patients with cystic fibrosis--results of a prospective pilot study].

Efficacy and safety of oral ciprofloxacin were studied in a prospective study at three cystic fibrosis centres, covering 24 in-patients suffering from cystic fibrosis and acute bronchopulmonary exacerbation. The patients were between 10 and 17 years of age. Pseudomonas infection was present in 75% of these patients. Despite frequent persistence of the pathogens, clinical improvement was noted in 75% of the treated children. A definite increase of the average MIC was not seen in 20 cases of persisting strains. No serious side effects occurred during the 14-day oral treatment course. Ciprofloxacin is a useful alternative to conventional parenteral treatment with antibiotics in patients suffering from cystic fibrosis and infections of the airways.

Adolescent↗
PubMed1993

[Findings of combined ventilation/perfusion scintigraphy in children with abnormalities of the bronchi, the lung and lung blood vessels].

Combined ventilation/perfusion scintigraphy with 133Xe/99mTc-HAM was performed within the framework of bronchological diagnostics in 38 children suffering from malformations of the bronchi, lungs and pulmonary vessels, and in 9 children after surgery of hernia of the diaphragm. The findings in stenoses, cysts in the bronchial system and in children with pulmonary vessel malformations, in one child with pulmonary agenesia and in a few other malformations, are presented. The significance of these findings in bronchological diagnosis in case of pulmonary malformations or clinical follow-up is discussed. Combined ventilation/perfusion scintigraphy is a valuable contribution to preliminary diagnosis and in follow-up of children with pulmonary malformations.

Bronchi↗
PubMed1993

[Treatment strategy in childhood bronchial asthma].

Although bronchial asthma is the most frequent chronic disease in childhood, not all of the affected children are readily recognised as asthmatics well in time for appropriate treatment. Since most of the children can get rid of the symptoms if all the available treatment methods are made use of systematically, early diagnosis and correct estimation of the disease pattern are essential for good long-term prognosis. New pathogenetic knowledge on the importance of inflammatory processes affecting the bronchial mucosa has definitely shifted the points of emphasis in asthma treatment as is evident from the international consensus recommendations. Focus of drug therapy is on prophylactic antiphlogistic treatment. Only in cases of severe asthma continual bronchodilatory medication is also recommended. The inhalative route is beneficial and feasible for all age groups. Long-term treatment, wherever necessary, also includes continual medical supervision in consultation with a paediatric pneumologist.

Anti-Inflammatory Agents↗
PubMed1992

A new simulation approach for the determination of the error of parameters of biological importance describing the growth of the Ehrlich ascites tumor of the mouse.

Some aspects of the growth of the Ehrlich ascites tumor of the mouse can be described by the logistic function. The parameters used are fitted to the experimental data in a nonlinear way. It is important to determine the error of these parameters of biological importance in order to discriminate between different consequences induced by various experimental situations by means of statistics. But often there is a gap between the data that are available and the stronger assumptions necessary for statistics. We propose a simulation approach which also works in a much larger range of similar situations to close this gap.

Animals↗
PubMed1992

Budd-Chiari syndrome as the primary manifestation of a fibrolamellar hepatocellular carcinoma.

An 18-year-old female patient was admitted with ascites, right upper abdominal tenderness and peripheral edema. Angiography showed complete occlusion of the vena cava inferior up to the level of the right atrium. By open heart surgery, masses of thrombotic material were pulled out of the v. cava inferior/vv. iliacae which histologically contained tumor cell populations consistent with a hepatocellular carcinoma. Celiacography showed a highly vascularized tumor in the right hepatic lobe. Histologically, it proved to be fibrolamellar subtype hepatocellular carcinoma.

Adolescent↗
PubMed1992

[The modification of Helicella obvia by Dicrocoelium parthenitae].

During the pasture period in 1990 the snail species Helicella obvia, collected in a dicrocoeliosis area in the east of Brandenburg, was investigated for Dicrocoelium sporocysts. Simultaneously in adult snails the condition of albumen gland was examined. Investigations showed that Dicrocoelium infection in the snail host impairs their reproduction ability and life expectancy. The term "parasite caused sterilisation" is suggested for changes which lead to infertility in the case of parasite infection.

Animals↗
PubMed1991

Minimization of intermediate concentrations as a suggested optimality principle for biochemical networks. II. Time hierarchy, enzymatic rate laws, and erythrocyte metabolism.

The multiobjective problem of minimizing all intermediate concentrations is solved for a model of glycolysis, the pentose monophosphate shunt and the glutathione system in human erythrocytes. It turns out that one solution out of four obtained corresponds qualitatively to the real system. Furthermore, it is shown that for any reaction system, the mentioned optimality principle implies distinct time hierarchy in that some reactions are infinitely fast and subsist in quasi-equilibrium. Finally, the relationships to the standard method of deriving enzymatic rate laws are discussed.

Energy Metabolism↗
PubMed1991

Radiotherapy and breast reconstruction: clinical results and dosimetry.

Immediate or delayed reconstruction using implants or autologous tissue transfer is increasingly offered to women undergoing mastectomy for breast cancer. Some patients require radiotherapy for prevention of local/regional relapse, and some for post-surgical local/regional recurrence. Others with augmented breasts may opt for conservative surgery and irradiation. At Washington University, 70 breast cancers were irradiated in 66 patients following mastectomy with reconstruction (N = 61) or wide local excision of an augmented breast (N = 5). Two patients elected to have a second reconstruction after an unsatisfactory initial result. Thus, 72 breasts were evaluated after radiotherapy for tumor control, complications, cosmesis, and patient satisfaction. Locoregional failure occurred in only five patients, one following adjuvant radiotherapy after mastectomy with reconstruction and four following radiotherapy for recurrent breast cancer within a reconstructed breast. Grade 2 or 3 complications occurred in 34 patients (51%). The complication rate was highest in autologous tissue transfer reconstructions. Cosmetic results were evaluated good/excellent in 49% by physicians and 67% by patients. Immediate reconstructions had fewer good/excellent physician evaluations (32%) compared with reconstructions performed at least 6 weeks after radiotherapy (55%). Transverse rectus abdominis flaps had the best cosmesis scores, followed by permanent silicone prostheses, tissue expanders, latissimus dorsi, and gluteal flaps. Only 48% of patients would choose to have the same reconstructive procedure again. Phantom interface dosimetry with a parallel plate chamber and TLD measurements was performed. Radiotherapy and reconstruction are not incompatible, but careful consideration of their relative timing and technique appear to be important in optimizing cosmesis while minimizing complications.

Adult↗
PubMed1991

Factors influencing the metacercarial intensity in ants and the size of Dicrocoelium dendriticum metacercarial cysts.

During the 1990 grazing season, ants found attached to plants were collected from sheep pastures at monthly intervals and examined for Dicrocoelium metacercariae. The species Formica pratensis and F. rufibarbis showed average metacercarial intensities of 76 and 38 respectively. In addition to the ant species, the intensity of infection was found to be dependent on the length of the ant. The volume of metacercarial cysts was influenced by the intensity per ant relative to ant length but not by the ant species or the time of ant collection.

Animals↗