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Biomedical subjects

S Scharf

Publications and source records attributed to S Scharf.

68 records · Page 4Linked to original sources
PubMed1980

Nonhomogeneous alveolar pressure swings in the presence of airway closure.

When thoracic gas volume (TGV) is determined plethysmographically, it is assumed that the alveolar pressure swings are homogeneous and are appropriately represented by pressure swings at the mouth. However, recent studies have demonstrated differences in total lung capacities derived from TGV measurements made at different levels in the vital capacity. These differences suggested that, in the presence of airway closure, alveolar pressure swings may be nonhomogeneous during a TGV determination. This possibility was tested in six dogs. Pressure at the airway opening (ao) was measured from an endotracheal catheter. A balloon-tipped catheter was passed into the right lower lobe (RLL) bronchus for measurement of RLL pressure. delta PRLL -- delta Pao was monitored during inspiratory efforts with the airway opening occluded. With the RLL balloon inflated, delta PRLL always exceeded delta Pao by an amount averaging 8.2%. Induction of a pneumothorax eliminated all differences between delta PRLL and delta Pao. Thus, during a TGV measurement, the chest wall may apply to the lungs nonhomogeneous forces that, in the presence of airway closure (e.g., chronic obstructive pulmonary disease and asthma) would result in nonhomogeneous alveolar pressure swings and potentially significant errors in the plethysmographic determination of TGV.

Animals↗
PubMed1978

[Compression tests on the human hip joint (author's transl)].

Three human pelvises were subjected to static loading in the course of the experiments. The values determined for the elasticity modules lie between 2 and 4.5 kp/min2. The values range between 5 and 14 kp/mm2 if only the compacta is considered. The experiments show that the elasticity modules obtained at cross sections through the Os coxae are higher than those for sections through the hip joint and its immediate surroundings. Here the elasticity module reaches the minimum value of 0.77 kp/cm2 (Fig. 1, cross section No.2, Table 3). The highest breaking strain was 1045 kp (Pelvis II). The longitudinal contraction of the three pelvis was 26.6 mm on average. For the mean height of 27.2 cm for the specimens used, this means that the pelvis, as a system (with hip joint) can be reduced in length by about 10% before a fracture occurs under static load conditions.

Biomechanical Phenomena↗
PubMedDate not supplied

Regional aspects and statistical characterisation of the load with semivolatile organic compounds at remote Austrian forest sites.

Spruce needles and humus layer of 25 remote forest sites spread all over Austria were investigated for their concentrations of PCDD/F, PCB, HCH, HCB, PCP, DDX and PAH. Influences of the sites' location on the detected concentrations have been identified: The north of Austria was characterised by a comparably higher overall pollutant load. In addition, altitudinal aspects were addressed. Between several compounds significant positive correlations have been identified, which were more pronounced for compounds with a stronger causal relationship. Pattern analyses allowed to identify--even for the remote sites--differences between the relative PCDD/F, HCH, DDX and PAH patterns of the sites. Partly, these different patterns were related to significantly higher or lower corresponding absolute concentrations of the sites.

Austria↗
PubMedDate not supplied

HLA-DR, DQ and DP typing using PCR amplification and immobilized probes.

A simple, rapid, and precise method of typing HLA class II polymorphism would be valuable in the areas of disease susceptibility, tissue transplantation, individual identification and anthropological genetics. Here we describe a method of analysing class II sequence polymorphism based on polymerase chain reaction (PCR) amplification and hybridization with oligonucleotide probes. One valuable property of sequence-based HLA typing strategies, like oligonucleotide probe hybridization, is that they reveal how and where two alleles differ, not simply that they can be operationally distinguished. The nature and location of HLA polymorphisms appears to be critical in disease association studies and are likely to be important in tissue typing for transplantation. New alleles at the DRB1, DPB1 and DQB1 loci are likely to be identified as this technology is applied to more and more samples, particularly in non-Caucasian ethnic groups. A new allele is uncovered as an unusual pattern of probe binding and then confirmed by sequencing. This pattern is observed because class II polymorphism is localized to specific regions and virtually all 'new' alleles have polymorphisms in the region of probe binding. Obviously, any new allele with a new polymorphic sequence in a region for which typing probes are not available would not be revealed by oligonucleotide typing. With the PCR primers and probes described here, 7 DQA1 alleles, 15 DQB1 alleles, 18 DPB1 alleles, and 32 DRB1 alleles are distinguished. Additional primers and/or probes can, of course, increase the allelic discrimination of oligonucleotide dot blot typing. These horseradish peroxidase (HRP)-labelled oligonucleotide probes are stable (greater than 2 years when stored at 4 degrees C) and the typing system is simple and robust. Over 500 samples from the CEPH pedigrees (unpublished data; A. B. Begovich, et al., manuscript in preparation) and greater than 1000 unrelated samples have been typed by this procedure. Although this dot blot/oligonucleotide hybridization procedure is a powerful and precise method of HLA class II typing, the complexity of the procedure increases as the number of probes required for analysis increases. The reverse dot blot method, based on an array of immobilized probes, allows the typing of individual samples in one single hybridization reaction. In this approach, a panel of unlabelled oligonucleotides are immobilized to a nylon membrane. The PCR product is labelled during the amplification reaction by using biotinylated primers and hybridized to the membrane. The presence of bound PCR product specifically hybridized to a given probe is detected using streptavidin-HRP conjugates and either chromogenic or chemiluminescent substrates.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMedDate not supplied

Radionuclide bone scanning in routine clinical practice.

Bone scintigraphy (scanning) is a quick and cost-effective method for evaluating potential bone lesions not visualized on plain radiography. Uses include evaluation of primary and metastatic bone tumors, treatment of bone pain due to tumor invasion, detection of occult fractures and stress injury, evaluation of postprosthesis joint pain, evaluation of metabolic bone disorders, and diagnosis of osteomyelitis. The main advantage of bone scanning is the ability to evaluate the entire skeleton rapidly with high sensitivity.

Bone Diseases↗
PubMedDate not supplied

Plastic surgery findings in Ethiopian immigrants.

We have encountered infrequent and unfamiliar types of morbid conditions requiring plastic surgery. We present here our clinical experience with five illustrative cases and discuss the typical features of each condition and its treatment.

Adult↗