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Biomedical subjects

R Voss

Publications and source records attributed to R Voss.

At least 19 recordsLinked to original sources
PubMed1992

Phytohemagglutinin gene expression during seed development of the runner bean, Phaseolus coccineus.

The expression of phytohemagglutinin (PHA) genes was studied in various tissues during the development of the seeds of Phaseolus coccineus cv. Hammond's Dwarf Scarlet by means of northern hybridization and reverse transcription polymerase chain reaction (RT-PCR). The expression is highly development-dependent, starting in the late stage (cotyledons begin to fill the endosperm cavity, i.e. 17 to 24 days after pollination), and tissue-specific. The highest levels of PHA-mRNA are found in the cotyledons (at a very late stage), much lower levels in the embryo axis. Very low levels could be detected in earlier stages of the endosperm, the integument, the funiculus, and probably also in the embryo suspensor. Some PHA mRNA was found in the cotyledons of dry seeds, indicating the presence of undegraded transcripts in mature seeds.

Base Sequence↗
PubMed1992

How often is dysplasia diagnosed by biopsy or smear examination? Application of a maximum likelihood based method to the assessment of detection rates in the nasal mucosa of nickel workers.

In view of the known increased risk of nasal carcinoma and the high prevalence of dysplastic lesions of the nasal mucosa among nickel workers, regular screening for the existence of possibly precancerous dysplastic lesions is offered to workers in a Norwegian nickel refinery. Unfortunately, available sampling techniques do not allow the identification of all subjects in whom dysplastic changes are present. Independent histological and cytological (brush cytology) diagnoses, obtained for each of a group of 90 workers, have been used to estimate, by a maximum likelihood method, the probabilities that existing dysplastic lesions will be detected by each of these two screening methods. In the group studied, cytology performed rather less well than histology in unambiguously detecting dysplasia. However, when cytological specimens showing irregular (possibly dysplastic) epithelial cells were grouped with those showing clear dysplastic changes, detection probabilities were estimated at 0.52 by histology and 0.57 by cytology. Detection probabilities were estimated to be higher among subjects with a previously known history of dysplasia, particularly by histology (P < 0.01), probably due to larger dysplastic areas. In view of both its greater facility and speed of sampling, and its greater acceptability, brush cytology may be preferable to biopsy sampling for the screening of large numbers of workers at risk.

Biopsy↗
PubMed1991

Corrected TMJ tomography: effectiveness of alternatives to SMV tracing.

An axial (SMV) radiograph has been widely used to determine parasagittal head position in TMJ tomograms. The purpose of this study was to investigate the efficacy of alternative anatomic methods for patient positioning in TMJ tomograms. The positioning methods studied included (1) rotation of the patient's head toward the film plane on the basis of the condylar orientation as determined by an SMV radiograph, (2) arbitrary rotation of the patient's head 20 degrees toward the film plane, (3) placement of the zygomatic arch parallel to the film plane, and (4) positioning of the posterior occlusal plane parallel to the film plane. Statistical analysis of the accuracy of the positioning techniques revealed no differences in the SMV, the zygomatic arch, and the arbitrary 20 degrees positioning. Aligning the posterior occlusal plane did not adequately align the mandible into a favorable radiographic position.

Analysis of Variance↗
PubMed1991

[Clinical behavior of NPM dental alloys after several years of intraoral service].

179 patients from the University Dental School of Cologne with 437 crowns and bridges cast of base metal alloys (Wiron 77, Wiron 88, Microbond NP2) were evaluated after clinical exposure between two and six years. Symptoms indicating corrosion, allergic or toxic reactions were not found. Cracking of ceramometal veneers occured in 2.8%. The survival rate of the examined crowns and bridges was 95% for those cast of Wiron 88 after four years of service and 97.7% for those of Wiron 77 after six years.

Corrosion↗
PubMed1990

Activation and inhibition of fibrinolysis in septic patients in an internal intensive care unit.

Disseminated thrombotic processes in the microcirculation are considered to be an important cause of multiple organ failure in septic patients. Fibrinolysis is one endogenous mechanism protecting the circulation from overwhelming thrombosis. Therefore, we looked for alterations of fibrinolytic parameters (tissue plasminogen activator (t-PA), tissue plasminogen activator inhibitor (PAI), D-dimer, euglobulin-clot-lysis-time (ECLT), plasminogen, alpha 2-antiplasmin) and of some coagulation parameters (prothrombin time, fibrinogen, platelets, antithrombin III, protein C, factor XII) in clearly defined septic patients and for the relations of these values to the severity of the disease (APACHE II-score). An increase in D-dimer and t-PA-antigen was registered in all patients, while factor XII and plasminogen were decreased, indicating an activated fibrinolysis. In contrast the systemic fibrinolytic capacity of the blood was strongly inhibited: t-PA-activity was not detectable, PAI-function was elevated, the ECLT was prolonged and alpha 2-antiplasmin was normal. Coagulation was moderately activated: the platelets, antithrombin III and protein C were decreased, the prothrombin time was prolonged and fibrinogen was normal. The changes in t-PA-antigen, PAI-function, factor XII, prothrombin time and antithrombin III were significantly related to the APACHE II-score of the patients. We conclude that the activation of coagulation is accompanied by an activation of fibrinolysis in the microcirculation, but that systemically the increased inhibitors of fibrinolysis (PAI, alpha 2-antiplasmin) induce a decrease of the fibrinolytic capacity of the blood. The severity of the disease determines the extent of the alterations.

Adult↗
PubMed1989

Anorectal malformations and Down syndrome.

During 1980 to 1986, 89 children with Down syndrome and 42 with imperforate anus were diagnosed among 64,870 liveborn infants in the Jewish population of Jerusalem. Two of the children had both Down syndrome and imperforate anus. This indicates a high incidence of imperforate anus among children with Down syndrome (2.2%).

Abnormalities, Multiple↗
PubMed1989

The dilemma of chromosomal mosaicism in chorionic villus sampling--'direct' versus long-term cultures.

Chromosomal mosaicism is one of several unanswered dilemmas in first-trimester prenatal diagnosis. We report the course of a pregnancy in which a normal karyotype was detected on direct CVS preparation and fetal blood, 100 per cent trisomy 21 in one long-term CVS culture, and low-rate trisomy 21 mosaicism in a second long-term CVS culture and amniocentesis. The phenotypically normal infant had a 6 per cent mosaicism of trisomy 21. It appears that a persistent low-rate mosaicism in different tissues may be indicative of the true status of the fetus.

Adult↗
PubMed1989

Isodisomy of chromosome 7 in a patient with cystic fibrosis: could uniparental disomy be common in humans?

Maternal isodisomy for chromosome 7 was observed in a 4-year-old cystic fibrosis patient with very short stature. In an examination of 11 DNA polymorphisms spanning the entire length of chromosome 7, no paternal contribution could be shown in seven informative loci. Paternity was examined with probes for five polymorphic loci on the Y chromosome, for the pseudo beta-globin locus on chromosome 11 and by Jeffreys's hypervariable probes. The results with the latter gave a probability of 3.7 x 10(-9) for nonpaternity. Chromosomal examination revealed a centromeric heteromorphism of chromosome 7 in the mother, for which the proband was homozygous. Isodisomy of the patient was thus shown for the entire length of a maternal chromosome 7. The mechanisms leading to this isodisomy involve at least two events of abnormal cell division, events that may be meiotic, postzygotic, or both. This proband is the second reported maternal isodisomy; both were detected through homozygosity for CF. Both patients had short stature, which could have been caused by parental imprinting, since similar results have been observed in isodisomic mice. Homozygosity due to uniparental descent in man should be kept in mind as a mechanism for recessive disorders, especially for chromosome 7.

Child, Preschool↗
PubMed1988

Beneficial effects of prostacyclin in a rabbit endotoxin shock model.

Thirty rabbits received an infusion of lipopolysaccharide B (75 micrograms/kg.h) over 4 hours (groups E, EI, EA; n = 10 each). Saline was given to a control group (C; n = 8). In group EI, prostacyclin (PGI2; 500 ng/kg.min) was given simultaneously to endotoxin. Into group EA animals, aspirin (20 mg/kg) was injected before the endotoxin infusion was started. PGI2 and aspirin both improved survival of animals (6/10 each vs. 2/10 in group E). The drop of platelet counts was significantly reduced by PGI2, while leukocyte depletion was similar in all endotoxin groups. PGI2 preserved the functional capacity of platelets as indicated by collagen stimulated aggregation and thromboxane formation. PGI2 but not aspirin significantly reduced renal fibrin deposition.

Animals↗
PubMed1988

Effect of monocytopenia on trauma-induced atherosclerotic lesions in the rabbit ear artery.

In a trauma model of atherosclerosis (repeated mechanical injury of the rabbit ear artery), rabbits were pretreated either with etoposid (inducing a monocytopenia) or with prednisolone (inhibiting monocyte function) to investigate the role of monocytes in traumatically induced plaque formation. Three weeks after the last injury the arteries were carefully examined. While a profound monocytopenia during the period of injuries did not at all influence the size of the plaque formation, this was almost completely inhibited in the prednisolone-treated rabbits. Obviously, the effect of prednisolone must be attributed to other pharmacological properties. Monocytes appear to be of less importance in purely trauma atherosclerosis models.

Animals↗
PubMed1988

Fetal duodenal obstruction. A high risk indicator for Down's syndrome.

Seven cases of fetal duodenal obstruction were diagnosed during an ultrasound examination. In 5 out of the 7, Down's syndrome was later diagnosed. The finding of duodenal obstruction in a fetus is a high risk indicator for Down's syndrome. We therefore recommend prenatal cytogenetic examination to be performed in such cases.

Adult↗