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Biomedical subjects

A Schmidt

Publications and source records attributed to A Schmidt.

At least 595 records · Page 33Linked to original sources
PubMed1986

Exercise-induced asthma after inhalation of aerosols with different osmolarities.

Five adult asthmatics completed five standardized exercise tests while inhaling aerosols with different osmolarities. The nebulized solutions were 2% NaCl (osmolarity = 616 mosm), 4% NaCl (osmolarity = 1232 mosm), 6.1% dextrose (osmolarity = 308 mosm = isoosmolar), 24.4% dextrose (osmolarity = 1232 mosm) and distilled water (osmolarity = 0). All the patients had EIA. During the study all conditions, except the osmolarity of the inhaled aerosols were kept constant. There was no statistical difference in the response to the exercise on the five days, the fall in PEF being 22.8% after exercise while inhaling 2% NaCl, 17.8% after inhaling 4% NaCl, 16.2 after inhaling 6.1% dextrose, 24.8% after inhaling 24.4% dextrose and 21.6% after exercise while inhaling nebulized distilled water, respectively. It is concluded that the osmolarity of the inhaled aerosol is of little or no importance in exercise-induced asthma.

Adult↗
PubMed1986

Lung function and bronchial hyperreactivity following exposure to four different temperatures and relative humidities.

Seven asthmatic patients were exposed to four different climatic conditions in a climate chamber. The four conditions were: 15 degrees C/30% relative humidity (RH), 15 degrees C/70% RH, 30 degrees C/30% RH and 30 degrees C/70% RH and the exposure time was 4 hours. Before and after the exposure the following lung function parameters were measured: PEF, FEV1, RV and TLC. After each exposure a bronchial challenge with histamine was performed by the doubling-dose principle. The results indicated no difference in lung function after exposure to the "extreme" conditions in this study (i.e. 15 degrees C/30% RH and 30 degrees C/70% RH, water content 3.5 and 19 g/kg dry air, respectively), while a decrease in RV and TLC was seen after exposure to the "middle" conditions (i.e. 15 degrees C/70% RH and 30 degrees C/30% RH, water content 7.5 and 8 g/kg dry air, respectively). No change in ventilatory capacity was seen, and the bronchial hyperactivity also remained unchanged. During the 4 hours exposure, measurements of FEV1 and PEF also remained constant. It is concluded that this kind of exposure is without great effect on the asthmatics condition.

Adult↗
PubMed1986

[Brazilian biomedical publications in the international scientific literature. Endemic communicable diseases].

The number of Brazilian periodicals listed in the Index Medicus dropped from 70 in 1964 to 15 in 1983, or 78%, while the total number of listed periodicals from other countries fell only 11%. The total number of articles published in Brazil on Chagas' disease, schistosomiasis, leishmaniasis, leprosy, malaria, and filariasis, and listed in the Index Medicus did not change significantly between 1965 and 1982, because, with the exception of the journal O Hospital, the Brazilian periodicals that published 74% of all articles on those diseases remained listed throughout the period considered. The predominant subjects in articles on endemic diseases were Chagas' disease and schistosomiasis, and in the later years there was a tendency to index more articles on basic than on applied research. The number of articles on Chagas' disease published by Brazilian authors directly in foreign journals increased considerably during the latter decade. Analysis of all the data together suggests that the developed countries select a specific portion of the Brazilian output of biomedical literature--which is kept listed in secondary and international publications or published directly in foreign journals--while another portion of the same output gradually loses visibility on the international scene.

Bibliographies as Topic↗
PubMed1986

Effects of pulmonary inhalation of water and histamine aerosols on nasal airflow resistance in man.

We investigated the effect of aerosols inhaled into the lungs on nasal airflow resistance (Rnaw) using a constant inflow pressure method with measured airflow. Isotonic saline and water aerosols produced no immediate significant change in Rnaw and forced expired volume in 1 s (FEV1); however, water gradually decreased FEV1 and increased Rnaw, the response being maximal 10-15 min after provocation. Histamine aerosol significantly increased Rnaw in healthy subjects, asthmatics and asthmatics with allergic rhinitis. There was also a corresponding decrease in FEV1. The increase in Rnaw and the decrease in FEV1 were reversed by inhalation of terbutaline (10 mg . ml-1). Similarly, terbutaline in patients with mild asthmatic attacks decreased Rnaw and increased FEV1. Since terbutaline applied locally into the nose is known to increase Rnaw, we conclude that lung provocation can increase nasal Rnaw, presumably via nervous pathways.

Adolescent↗
PubMed1986

Measurement and regulation of nasal airflow resistance in man.

A method for measuring human nasal airflow resistance (Rnaw) is described. Air flows at constant pressure through both nasal cavities via a face mask and out through the mouth. Airflow is inversely related to Rnaw. The method has several advantages over many other methods for measuring Rnaw, in particular allowing aerodynamic separation of nose and lungs, and frequent measurements over long periods without discomfort to or intervention with subjects or patients. We have used this method to obtain standard values of Rnaw in healthy subjects and in patients with asthma and/or rhinitis. Age has a negative correlation with Rnaw but no sexual difference was seen. Cigarette smoking increases Rnaw especially in young adults. Patients with rhinopathy have much higher resistances than healthy subjects, but those with asthma alone do not. Rnaw is sensitive to changes in ventilation and lung volumes; deep inspiration and oral hyperventilation decrease Rnaw, while deep expiration, nasal hyperventilation and breath-holding increase it. Hypoxia and hypercapnia locally applied in the nose increase Rnaw. It is suggested that these changes are predominantly due to changes in control of the nasal vascular bed.

Adolescent↗
PubMed1986

Long-term effect of magnesium pyridoxal 5-phosphate glutamate in rabbits developing hypercholesterolemia.

36 male rabbits were fed with a diet enriched with 20 g cholesterol/kg for a period of 8 weeks under a strict daily dietary control. Magnesium pyridoxal 5-phosphate glutamate (MPPG, Sedalipid) was supplemented to the diet at different quantities. Hypercholesterolemia developed later and less pronounced in animals receiving a medium or high dose of MPPG. Microscopical analysis indicated a protective effect of MPPG on calcium deposition in the aorta. The fatty acid pattern in serum showed only minor differences and was unchanged in liver extracts in animals supplemented with MPPG. This observation suggest that MPPG may act on the mechanism of cholesterol absorption in the intestine.

Animals↗
PubMed1986

[Morphometric and histochemical studies of the skeletal muscles of patients with chronic renal failure and dialysis patients].

In 19 patients with chronic renal insufficiency in the stage of compensated retention, 20 patients undergoing dialysis and 24 patients with normal renal function muscle tissue was taken by an open biopsy and investigated histologically, histochemically as well as morphometrically. A neurogenic atrophy stood in the foreground of the histologic changes of the striated musculature in uraemia, a pure type II atrophy was found more infrequently. In the patients undergoing dialysis frequency and size of these disturbances were more distinct. Except for a possible influence of a disturbed calcium metabolism other pathogenetic factors supposed in literature could not be found.

Adult↗
PubMed1986

The significance of the detection of alkaline phosphatase in the diagnosis of neuromuscular diseases.

The occurrence of alkaline phosphatase was observed in regenerating muscle fibres, especially in polymyositis and muscular dystrophy. No differences in the appearance of this enzyme were seen in these diseases. Alkaline phosphatase was not encountered in neurogenic atrophy, with the exception of cases of an accompanying myopathy. These cases show a clear picture without problems in the morphological differential diagnosis. The histochemical demonstration of the enzyme is helpful in the differential diagnosis of neurogenic atrophy and muscular dystrophy of benign type. It is of no use to distinguish between muscular dystrophy of malignant type and parenchymatous polymyositis.

Alkaline Phosphatase↗
PubMed1985

High-uptake and low-uptake forms of proteoglycans secreted by arterial smooth muscle cells.

Cultured arterial smooth muscle cells synthesize and secrete two types of sulfated proteoglycans, designated as proteoglycan A and B, into the culture medium. They are isolated as immunologically distinct monomers with relative molecular masses of 280 X 10(3) and 180 X 10(3) and are characterized as chondroitin-sulfate-rich (A) and dermatan-sulfate-rich (B) proteoglycans. Both proteoglycan A and B were labelled with [35S]sulfate and used for studies of endocytosis. Uptake of proteoglycan B by arterial smooth muscle cells shows saturable kinetics. At saturation (500 microM) one cell may endocytose up to 1.5 X 10(6) proteoglycan B molecules/h. Proteoglycan A is internalized at a 10-fold lower rate. No saturation kinetics were observed at high proteoglycan A concentrations (500 microM). Endocytosis of proteoglycan B in the presence of an excess of proteoglycan A and vice versa suggest that proteoglycan A and B do not compete for the same receptor site. Free hyaluronate or chondroitin sulfate do not inhibit the uptake of proteoglycan B or A. The results suggest that proteoglycan B is internalized by arterial smooth muscle cells via a high-affinity receptor-mediated process, whereas proteoglycan A is taken up by fluid endocytosis and/or by low-affinity endocytotic processes.

Animals↗
PubMed1985

Right ventricular function in patients with chronic obstructive pulmonary disease.

Simultaneous right heart catheterization and radionuclide ventriculography were performed in 27 patients with a wide range of chronic obstructive pulmonary disease. Central hemodynamics and radionuclide studies were done at rest and during exercise. In the resting state the right ventricular ejection fraction (RVEF) was in the normal range (43.3 +/- 6%). During exercise a significant (p less than 0.001) decrease of RVEF to 38.8 +/- 6.7% occurred. The pulmonary artery mean pressures were 19.9 +/- 3.8 at rest. During exercise a significant (p less than 0.001) increase to 41 +/- 9.8 mm Hg occurred. There was a linear relationship between pulmonary pressures and RVEF during exercise in patients with pulmonary artery pressures not exceeding 35 mm Hg. In patients with right ventricular end-diastolic wall thickness greater than or equal to 6 mm a curvilinear relationship between these parameters could be observed with a flattening of the curve at higher pressures (greater than 35 mm Hg) and lower ejection fractions (less than 35% RVEF). Radionuclide ventriculography cannot substitute for right heart catheterization. Echocardiography is useful for interpretation of right ventricular ejection fractions in advanced chronic obstructive pulmonary disease.

Aged↗
PubMed1985

Structural and functional studies on the interstitial collagen genes.

An understanding of the molecular mechanisms which control expression of the type I and III collagen genes may provide a rational basis for the design of more effective therapeutic approaches to fibrotic diseases. The structure of the interstitial collagen genes is reviewed and potential sites which could control their expression are examined. One approach to the study of the regulation of these genes consists in DNA-mediated gene transfection experiments and is discussed in this paper.

Animals↗
PubMed1985

Recurrent mutation pressure does not explain the prevalence of the marker (X) syndrome.

In order to test the hypothesis that the high prevalence of the mar(X) syndrome is caused by a high mutation rate in male germ cells only, the fraction of new mutants among mothers of probands in 112 informative families has been examined by segregation analysis among their brothers and sisters. The estimated fraction of new mutants among these mothers is much lower than expected if a stable equilibrium existed between an unusually high mutation rate and a selective disadvantage of mentally retarded, male and female mar(X) carriers. Hence, the above-mentioned hypothesis could not be confirmed.

Female↗
PubMed1985

Initiation factors eIF4A and C1 from wheat germ and the formation of mRNA X ribosome complexes.

The binding of ribosomes to mRNA is analyzed in a fractionated system from wheat germ with [3H]uridine-labeled poly(A)+ RNA prepared from germinating wheat embryos. The reaction requires factors eIF3, eIF4C, and eIF5; Met-tRNA and the Met-tRNA binding system; either GTP or GMP-PNP; ATP; and factors C1 and eIF4A. These requirements are identical to those previously found to be necessary for formation of ribosome X Met-tRNAMeti complexes, with the exception of ATP, and factors C1 and eIF4A. The function of factors C1 and eIF4A is therefore specifically related to the mRNA attachment reaction. The presence of GTP in the mRNA binding reaction results in the formation of 80 S ribosome complexes, while with GMP-PNP only 40 S ribosome complexes are formed. Ribosome binding to native reovirus RNA in the fractionated wheat germ system is similar to the reaction with poly(A)+ RNA, strongly requiring ATP and factors C1 and eIF4A. Binding to inosine-substituted reovirus RNA, however, is only partially dependent upon ATP, and both the ATP-dependent and the ATP-independent binding reactions strongly require factor C1 and are substantially stimulated by factor eIF4A. The ATP-independent reaction is inhibited by pm7GDP, has a strong requirement for Met-tRNAMeti, and the 40 S ribosome complex is stable to RNase. These results indicate that the ATP-independent binding of ribosomes to inosine-substituted reovirus RNA proceeds through the normal initiation process. They further suggest that neither factor C1 nor eIF4A function exclusively to unwind mRNA secondary structure. Since eIF4A is required for the ATP-independent binding to inosine mRNA, and at the same time interacts with ATP in the reaction with ATP-requiring mRNAs, this factor may have two roles in protein chain initiation, one related to the mRNA X ribosome interaction, and one related to the function of ATP.

Adenosine↗
PubMed1985

Mercuric reductase structural genes from plasmid R100 and transposon Tn501: functional domains of the enzyme.

The nucleotide sequence for the 2240 bp of plasmid R100 following the merC gene of the mercuric resistance operon has been determined and compared with the homologous sequence of transposon Tn501. The sequences following merC and preceding the next structural gene merA are unrelated between R100 and Tn501 and differ in length, with 72 bp in Tn501 and 509 bp in R100. The R100 sequence has a potential open reading frame (ORF) for a 140 amino acid polypeptide with a reasonable translational start signal preceding it. The merA genes contain 1686 (Tn501) and 1695 (R100) bp respectively. When optimally aligned, the merA sequences differ in 18% of their positions. These differences were clustered in specific regions. In addition, there was one nucleotide triplet in the Tn501 sequence which has no counterpart in the R100 sequence and one dodecyl-nucleotide sequence in the R100 sequence without counterpart in Tn501. Thus the predicted merA polypeptide of Tn501 contains 561 amino acids and the R100 counterpart contains 564 amino acids. Comparison of the R100 mercuric reductase sequences with that for human glutathione reductase [Krauth-Siegel et al.: Eur. J. Biochem. 121 (1982) 259-267], for which there is a 2 A resolution electron density map [Thieme et al.: J. Mol. Biol. 152 (1981) 763-782] shows a strong homology, with 26% identical amino acids and many conservative substitutions. This homology allows the conclusion that the active site of these enzymes and the contact positions for flavin adenine dinucleotide (FAD) and NADPH are highly conserved, while the amino- and carboxyl-terminal sequences differ.

Amino Acid Sequence↗