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Biomedical subjects

J Roos

Publications and source records attributed to J Roos.

At least 19 recordsLinked to original sources
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↗
PubMed1987

Cold provocation test results from a 1985 survey of hard-rock miners in Ontario.

A total of 143 miners, 6 ex-miners, and 42 referents from five mines in northern Ontario were examined with a cold provocation test. The skin temperatures, measured by thermocouples at the tips of the fingers and thumbs were recorded at 5-s intervals throughout the immersion in cold water (10 degrees C) for 10 min and during the recovery period. The finger skin temperature was followed until 99% recovery had occurred as compared to the starting temperature. For the referents and the vibration-exposed subjects, the results by separate stage of the Taylor-Pelmear scale for hand-arm vibration syndrome were compared. There were statistically significant differences in the mean finger temperature at the 50, 75, 90, and 95% recovery times between stages 0, 0T/0N, and stages 1 through 3 combined, as well as significant differences between stages 1, 2, and 3. The mean temperature at 10 min and the mean hyperemia temperature for eight fingers combined were compared between the miners and referents. There were significant differences in the mean temperature at 10 min and in the hyperemia temperature between the referents and miners in stage 0T/0N, as well as between the referents and the miners in stages 1 through 3 combined. For the worst finger (defined as that with the lowest temperature at 10 min) there was an increasing trend towards a lower hyperemia temperature and delay in recovery time from stage 0 to stages 2 and 3 combined.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Subcapsular hematoma of the liver in an eclamptic crisis].

A patient is described who showed signs of eclampsia in the 31st week of first pregnancy. The cause of shock proved to be a subcapsular hematoma in the liver and it was accompanied by a hematothorax. The diagnosis was made by CT-scanning. The pathogenesis is discussed.

Adult↗
PubMed1978

Action of testosterone propionate on the gonadotrophic function of the pituitary gland in the cyclic female rat.

Four-day cyclic female rats were injected with 5 mg testosterone propionate (TP) at dioestrus II at 10.00. A blockade of ovulation was observed on the morning of oestrus in most of these animals. No LH surge occurred in the afternoon of pro-oestrus. By contrast the size of follicles exceeding 400 micrometer in diameter did not differ in the afternoon of pro-oestrus in TP-treated and control females. Moreover both the number of follicles and the blood FSH concentration appeared to be higher at 14.00 on pro-oestrus in TP-treated than in control females. The effects of TP in vivo are thus in agreement with the observations which showed that TP caused a blockade of LH release and the maintenance of FSH release in vitro.

Animals↗
PubMed1978

The adrenal cortex and the luteotrophic action of estrogens during the estrous cycle in the rat.

The aim of this study was to evaluate the effects of estradiol benzoate (EB) on ovarian progesterone secretion in the presence or in the absence of the adrenals. 4-day cyclic female rats were injected with 10 microgram EB on the morning of diestrus I. An increase in the rate of ovarian progesterone secretion in diestrus II at either 10--11 a.m. or at 2 : 30--3 : 30 p.m. was only observed in one of two experimental series. A very significant increase in the peripheral blood progesterone concentration was noted in adrenalectomized EB-treated females as compared to EB-injected intact females, thus suggesting that the adrenals might inhibit the luteotrophic action exerted by EB on the ovary. Experiments in dexamethasone (DEX)-EB-treated females confirmed this view. Peripheral blood progesterone concentration was significantly greater in DEX-EB-treated females than in EB-treated females. The possible mechanisms were discussed in the light of experiments involving the administration of metyrapone (MET) prior to EB injection. While blood progesterone concentration increased following MET-treatment only, no cumulative effects resulted from combined MET and EB-treatment. Progesterone of adrenal origin was then supposed to be implicated in the inhibitory action of the adrenal cortex on the luteotrophic action of EB in cyclic female rats.

Adrenalectomy↗
PubMed1977

Interlaboratory oral anticoagulant quality assessment by the Netherlands Federation of Thrombosis Services.

The 50 laboratories of the Netherlands Federation of Thrombosis Services, covering a population of 9 million and responsible for the laboratory control of approximately 150,000 patients under oral anticoagulation, have participated since 1974 in a voluntary external and internal quality control program. The external program comprises a monthly distribution to the member laboratories of a series of artificially prepared control blood samples, two of which are identical. The overall variation of the coagulation times found were 10% (CV) in 1974 and 8% (CV) in 1975. Performance improved rather abruptly at the beginning of 1975, after the application of a tight methodological standardization and improvement by the manufacturer of the thromboplastin preparation (Thrombotest) used by the great majority of the laboratories involved. The main source of variation was found to be random error in the Thrombotest determination, approximately 6%. Interbatch variation of Thrombotest and inter-aliquot variation of control blood samples both do amount to approximately 3%(CV). In terms of rabbit tissue thromboplastins, which have a lower sensitivity than Thrombotest (i.e., a flatter slope of the correlation between the PT and the anticoagulant effect), the total variation in the performance of the Dutch laboratories is 2.2--5.6% (CV), which is unusually low. The main reason for this is the fact that the laboratories can rely not only on the services of the manufacturer but also on a central information office and a reference laboratory responsible for the preparation of the control blood as well as the standardization (calibration) of thromboplastin.

Anticoagulants↗