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Biomedical subjects

J Roos

Publications and source records attributed to J Roos.

At least 55 records · Page 3Linked to original sources
PubMed1994

Luteinizing hormone-releasing hormone (LHRH)-expressing cells in the nasal septum of human fetuses.

In 12-19 weeks old human fetuses, LHRH-immunoreactive (LHRH-Ir) cells were detected in the nerve fascicles arising from the vomeronasal organ (VNO), from their origin to their end point at the medial aspect of the olfactory bulb (vomeronasal and/or terminal nerves). In one 22-weeks-old fetus, LHRH-Ir cells were present only in the upper part of the nasal septum, in the nerve fascicles crossing the cribriform plate. No LHRH cells could be detected in two fetuses, 23 and 36 weeks old. Our results are discussed with regard to the migratory hypothesis of LHRH cells from the medial olfactory placode to the brain.

Abortion, Induced↗
PubMed1994

A screen for yeast mutants with defects in the dolichol-mediated pathway for N-glycosylation.

Dolichol in the form of dolichyl phosphate participates in the synthesis of N- and O-linked glycoproteins and phosphatidylinositol-linked proteins in the yeast Saccharomyces cerevisiae. In this organism, as well as in higher eukaryotes, a number of the enzymes in the polyisoprenoid and glycoprotein biosynthetic pathways have not been identified. In this study, we have developed a convenient, highly sensitive assay that uses one of the end products of the dolichylphosphate synthetic pathway, oligosaccharide-diphosphodolichol, and a 125I-labeled peptide substrate for N-linked glycosylation to screen a collection of temperature-sensitive yeast mutants for defects in protein glycosylation. By using a combination of biochemical and genetic procedures, the defective mutants were grouped into three categories: those containing defects in dolichyl-phosphate synthesis (class 1), lipid-linked oligosaccharide assembly (class 2), or oligosaccharide transferase activity (class 3). Among the mutants identified by this screen were sec59 (which encodes dolichol kinase) and a mutant that affects the activity of the ALG1-encoded mannosyltransferase that forms dolichol-PP-(GlcNAc)2Man1. Of particular interest was a mutant that exhibits a temperature-sensitive defect in oligosaccharide transferase activity. This mutant, meg1 (microsomal protein essential for glycosylation 1) assembles a complete oligosaccharide chain and, therefore, is likely to be a class 3 mutant. We report the cloning of MEG1, the gene that rescues the oligosaccharide transferase activity defect in this mutant. A number of criteria distinguish this gene from previously described genes in this pathway.

Amino Acid Sequence↗
PubMed1994

Compartment syndrome after fracture of the distal radius.

A compartment syndrome of the forearm after a fracture of the distal radius is presented. This rare complication should be considered after high velocity trauma in young people. In this setting, we prefer general anesthesia for fracture reduction. Fracture fixation and avoidance of circular casts are recommended. Repeated evaluation allows early detection of compartment syndrome. Fasciotomy should be done if this syndrome occurs.

Adult↗
PubMed1993

Histologic investigations on 33 retrieved Nobelpharma implants.

Thirty Nobelpharma implants were retrieved from 17 patients despite a remaining clinical stability, after between 1 and 16 years of clinical function. The reasons for implant removal were bone resorption in combination with soft tissue disorders, psychological causes, implant fracture and post mortem cases. When measured at the cortical passage, there was an average of 84.9% direct bone-to-implant contact and 81.8% average surface bone area in individual threads as evaluated in a computerized morphometric system at the light microscopic level.

Adult↗
PubMed1993

Prevalence of small opacities in chest radiographs of nickel sinter plant workers.

Radiographs from 745 nickel sinter plant workers were taken and classified by five readers using the International Labour Office (1980) protocol. Each reader worked independently and the films were randomly mixed with films from a non-dust exposed office population and also with films from subjects known to have silicosis or asbestosis. The prevalence of small irregular opacities was selected as the outcome of interest. In the sinter workers this was within the range identified in cigarette smokers or in workers exposed to dusts of low fibrogenicity. Only minimal evidence of small round opacities was noted. There was no evidence from the chest radiographs that exposures to high concentrations of dusts containing compounds of nickel caused an inflammatory or fibrogenic response in the lungs of the exposed population.

Adult↗
PubMed1991

Peptide binding by protein disulfide isomerase, a resident protein of the endoplasmic reticulum lumen.

Previously we had demonstrated by photoaffinity labeling that a 57-kDa protein of the endoplasmic reticulum can bind and become covalently linked to glycosylatable photoreactive peptides containing the sequence-Asn-Xaa-Ser/Thr-. Subsequently, it was found that this protein, called glycosylation site-binding protein, was a multifunctional protein, i.e. it was identical to protein disulfide isomerase (PDI), the beta-subunit of prolyl hydroxylase and thyroid hormone-binding protein. In this study, the peptide specificity for binding to this 57-kDa protein, hereafter called PDI, has been investigated in more detail using photoaffinity probes. The results reveal that although N-glycosylation by oligosaccharyl transferase in the endoplasmic reticulum has an absolute requirement for an hydroxyamino acid in the third amino acid residue of the glycosylation site sequence, no such specificity is observed in the binding of such peptides to PDI. In addition to the lack of specificity for an hydroxyamino acid in the third residue position, no specificity was observed for the asparagine residue in the first position. Thus, binding is not restricted to peptides containing N-glycosylation sites. We have investigated the discrepancy between this apparent lack of sequence specificity and earlier results indicating that binding of peptides to PDI was specific for N-glycosylation site sequences. We now demonstrate that PDI in the lumen of microsomes is more efficiently labeled by peptides containing photoreactive-Asn-Xaa-Ser/Thr- sequences than by nonacceptor site sequences because the former become glycosylated. This increased labeling does not occur because the glycosylated form of the probes are preferentially recognized by PDI. Rather, it appears that increased polarity of the affinity probe after attachment of the oligosaccharide chain prevents its exit from the sealed microsomes, in effect concentrating it within the lumen of the microsome. These results, coupled with other studies on the multifunctional nature of PDI, suggest that the observed peptide binding may be a manifestation of the ability of PDI to recognize the backbone of polypeptides in the lumen of the endoplasmic reticulum.

Affinity Labels↗
PubMed1990

Lordosis behavior in intact male rats: effects of hormonal treatment and/or manipulation of the olfactory system.

The aim of this study was to investigate the olfactory mechanisms regulating the display of lordosis behavior in intact Wistar male rats bred in our colony. Gonadally intact males show a low capacity to respond by lordosis to male mounts and were insensitive to manipulations of the olfactory system (exposure to the odor of male urine or accessory bulb removal (AOBR)) which have been previously shown to facilitate the display of lordosis behavior in orchidectomized animals primed with ovarian hormones. Treatment with either estradiol benzoate (EB) or EB and progesterone (P) consecutively did not render these gonadally intact animals sensitive to the effects of AOBR. By contrast exposure to male urine was capable of facilitating the display of lordosis behavior in intact male rats given EB + P consecutively. These results are discussed in the light of previous findings showing that (1) two inhibitory structures, the accessory olfactory bulb and the septal and preoptic areas, are involved in the control of lordosis behavior in the male rat; (2) the effects of olfactory cues on the display of lordosis behavior are dependent on the action of both EB and P in orchidectomized animals.

Animals↗
PubMed1990

Occupational asthma caused by latex in a surgical glove manufacturing plant.

A 33-year-old latex glove inspector was diagnosed as having occupational asthma on the basis of peak flow and methacholine-responsiveness changes related to workplace exposure. She had latex sensitivity by skin prick testing. This finding led to a survey of her workplace. Of the 81 workers, 84% completed a questionnaire to assess work-related respiratory symptoms, 79% underwent skin prick testing to latex and six other workplace chemicals, and 62% performed workshift spirometry. Seven workers had spirometric changes consistent with asthma, of whom five had greater than or equal to 15% fall in FEV1 during the workshift. Six of these workers underwent methacholine-challenge testing, and three were found to have a significant improvement in responsiveness to methacholine away from work, suggestive of occupational asthma. Two of these workers had positive skin test responses to latex. Including the index case, 6% of workers who had pulmonary function testing had findings of latex-related occupational asthma. Skin test responses to latex occurred in 11% of workers tested. Our findings suggest that latex should be considered among the causes of occupational asthma.

Adult↗
PubMed1989

Prepubescent hormonal control of the development of accessory olfactory bulbs in the male rat.

The effects of androgen treatment (TP) from postnatal day 20 (P20) onwards on the accessory olfactory bulbs' (AOB) development were studied in rats orchidectomized at birth (PO) or on P20. TP failed to restore impaired AOB development in the rats castrated at PO but completely restored AOB development in those castrated at P20. Androgen secretion during both the perinatal and prepubescent periods appeared to be critical for male AOB development.

Aging↗
PubMed1989

[The assessment of social relations in 6 to 12-year-old children in a child and adolescent population in psychiatric consultation].

Starting from Schmiedeck's "personal sphere model" we tried to develop a similar procedure for children (age range 6 to 12 years). It should enable us to analyze the social relationships of a patient from his/her point of view. We examined 85 children of child/adolescent-psychiatric population with the presented method. It focuses upon drawings of the children and assessment of their relationships. The number of closely related persons and the frequency of interpersonal/social contacts allow to estimate the degree of embeddedness of the child into his/her social context. Importance and significance of indicated partners of interaction can be determined by the attachment the child expresses and receives. These assessments give information about the likes and dislikes for the related persons. The range of social experience extends equally for boys and girls as they grow older. At all age levels girls have more social contacts than boys. The sibling relations of the girls show more inconsistencies than those of the boys. Younger children have the tendency to name only the mother as family member. Neurotic and emotionally disturbed children express fewer wishes. Children with social behaviour disorders suffer less from the loss of a closely related person than children with emotional disturbances.

Affective Symptoms↗
PubMed1988

Sexual differences in the development of accessory olfactory bulbs in the rat.

The aim of this investigation was 1) to compare the development of AOB in male and female rats before birth, early after birth, and at later stages of sexual immaturity and maturity 2) to examine the effects of early and delayed castration after birth on AOB development in the male rat. A significant increase of the surface area of AOB was observed in both sexes from birth until postnatal day 7, but AOB was found to be larger in males than in females. From the end of the first postnatal week AOB stopped growing until day 40 in both males and females. After this time AOB resumed its development until day 60 in males, while no changes occurred in females over the same period. Castration of males at birth or six hours later impaired development of AOB. Castration of males on postnatal days 20 or 30 also impaired AOB development until day 60. The results strongly suggest that the development of AOB in the male rat is dependent on the two well known "perinatal" and "adult" phases of the endocrine activity of the testes.

Age Factors↗