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Biomedical subjects

P Kaur

Publications and source records attributed to P Kaur.

At least 127 records · Page 7Linked to original sources
PubMed1986

Standardization and demonstration of antibody-coated Candida in urine by direct immunofluorescence test.

Acetone, carbontetrachloride, ethyl alcohol, mixture of ethyl alcohol and acetone, and heat were assessed for fixative property for direct immunofluorescent (IF) staining of antibody-coated Candida cells. The results indicated that ethyl alcohol was the most suitable fixative for the test. Antisera containing 16 units of Candida albicans type A agglutinin were found essential to get optimal detectable fluorescence of antibody-coated yeast cells. IF test showed cross reactivity between the yeasts of C. albicans and C. tropicalis. However, there was no cross reactivity with the conidia of A. flavus. The direct IF test could demonstrate antibody-coated yeast cells and pseudomycelia in deposits of urine in the direct smear. It correlated well with microscopy and culture studies. At times, it could demonstrate the antibody-coated yeasts earlier than routine significant culture. It could also differentiate the significant from non-significant fungal isolates from urine.

Agglutination Tests↗
PubMed1986

Circadian variation in migration velocity in small intestinal epithelium.

The variation in migration rates of cells within the small intestinal epithelium was studied over a 24-hr period at 3-hr intervals (migration of cells was studied independently for the crypts and the villi using the changing distributions of [3H]TdR labelled cells as an indicator of cell migration). Clear changes in the rates of cell movement were observed during a 24-hr period for both crypt and villus epithelium. The rates of cell migration in these two compartments did not correlate well with the exception of samples taken at 18.00 hours. At this time of day there appeared to be no cell movement at all in either crypts or villi. There was not a good correlation between the migration velocity throughout the day and the changes in the number of mitoses. It is proposed that mitotic rates do not directly govern migration rates but that the converse may be true. Further, the lack of correlation between crypt and villus migration rates at any time of day suggest that the mechanisms controlling all movement in these two regions of small intestinal epithelium may be different.

Animals↗
PubMed1986

Cell migration velocities in the crypts of the small intestine after cytotoxic insult are not dependent on mitotic activity.

The role of mitotic activity in the normal process of intestinal epithelial cell migration was investigated. The movement of [3H]TdR-labelled cells in the crypt-villus column was used to study migration both in the crypts and on the villi. Radiation alone or in conjunction with other cytotoxic agents (hydroxyurea, cyclophosphamide and isopropyl-methane sulphonate) was used to eliminate cell division activity and to decrease crypt cellularity. This was done in order to determine the role of 'mitotic pressure' in driving cell migration. It has been clearly demonstrated in this study that cell migration, both within the crypts and on the villi, can take place in the complete absence of mitotic activity and after a drastic decrease in crypt cellularity. These results add to the continually mounting evidence against the idea that the 'pressure' generated by mitoses within the crypt or indeed in other epithelial regions is responsible for propelling epithelial cells. The data also demonstrate that the migration mechanisms are resistant to cytotoxic exposure.

Animals↗
PubMed1986

Effects of puromycin, cycloheximide and noradrenaline on cell migration within the crypts and on the villi of the small intestine. A model to explain cell movement in both regions.

The normal process of cell migration, occurring as part of the replacement scheme within the small intestinal epithelium, was investigated extensively. The effects of puromycin, cycloheximide and noradrenaline on the movement of tritiated thymidine [( 3H]TdR) prelabelled crypt or villus cells have been studied. These studies have led to the formulation of a model for the mechanism of cell migration, postulating that the crypts and villi behave as separate units, with regard to cell migration, in addition to their distinct structural and functional properties. It is proposed that crypt cell migration is an active process requiring protein synthesis and protein glycosylation, whilst movement of villus epithelial cells is passive, depending on the continued contraction of smooth muscle cells in the lamina propria.

Animals↗
PubMed1986

Intestinal cell proliferation. I. A comprehensive model of steady-state proliferation in the crypt.

Cell replacement in the crypt of the murine small intestine has been studied and modelled mathematically under steady-state conditions. A great deal of information is available for this system, e.g. cell cycle times, S phase durations, the rate of daily cell production, the Paneth cell distribution etc. The purpose of the present work was to consider simultaneously as much of these data as possible and to formulate a model based upon the behaviour of individual cells which adequately accounted for them. A simple mathematical representation of the crypt has been developed. This consists of sixteen stem cells per crypt (TC = 16 hr, TS = 9 hr), and four subsequent transit cell divisions (TC = 11 to 12 hr, TS = 8 hr) before maturation. Experimental data considered to test the modelling were LI and data on the number of vertical runs of similarly labelled cells. All data were obtained from the ileum after 25 microCi [3H]TdR given at 09:00 hours. A number of alternative assumptions have been considered and either accepted or rejected. Two alternative model concepts of cell displacement explain the data equally well. One is dependent upon strong local cell generation age determinance while the other could accommodate any weak local cell displacement process in conjunction with an environmental cut-off determinant at the middle of the crypt. Both models provide new interpretations of the data, e.g. certain rates of lateral cell exchange between neighbouring columns (250 to 350 per crypt per day out of a total of 420 cell divisions per day) can be concluded from run data, while LI data provide information about the mechanisms involved in maintaining a position-related age order in the crypt.

Animals↗
PubMed1986

Survival and growth of Bacillus cereus in bread.

Bread doughs were artificially inoculated with spores of six Bacillus cereus strains at different inoculum levels and counts of survivors in bread determined during storage at 27.5 degrees C. No B. cereus were isolated from the centre crumb of 400 g loaves when the dough contained less than 10(4) spores/g whereas with 800 g loaves survival occurred with doughs containing 5.0 X 10(3) spores/g. With all strains there was a period of at least 24 h before multiplication took place in the bread. The inclusion in dough of 0.2% of calcium propionate, based on flour, effectively delayed germination and subsequent multiplication of B. cereus spores. It is concluded that the risk of food poisoning due to the presence of B. cereus in bread is minimal.

Bacillus cereus↗
PubMed1986

Mechanism of resistance to silver ions in Klebsiella pneumoniae.

The uptake of silver by an experimentally derived silver-resistant Klebsiella pneumoniae strain was three to four times lower than the uptake by a susceptible strain. Spheroplasts of the two strains showed no difference in uptake. AgNO3 at a concentration of 40 micrograms/ml decreased the succinate dehydrogenase activity in susceptible and resistant strains by 100 and 18%, respectively. More than one resistance mechanism may be involved.

Drug Resistance, Microbial↗
PubMed1984

Mucoid anaplastic hepatoblastoma. A case report.

A case of an unusual type of hepatoblastoma in a 5-month-old male infant is described. The tumor showed the following unusual features as compared with the epithelial and mixed types of hepatoblastoma: (1) The tumor cells presented a primitive anaplastic appearance without any resemblance in terms of cytologic features or arrangement to embryonal or fetal liver. (2) Abundant mucoid material containing acid mucopolysaccharide was present giving a slimy, gelatinous, gross appearance to the tumor and its metastases. (3) Well-defined tubular structures were present in some foci within the tumor parenchyma. (4) The tumor resulted in a rapidly fatal course, with metastases to the lungs and widespread peritoneal seeding despite complete surgical resection of the primary tumor. Yolk sac carcinoma and undifferentiated (embryonal) sarcoma of the liver were considered in the differential diagnosis. On electron microscopic examination, the tumor cells showed cytoplasmic features and junctional complexes consistent with their epithelial origin. Alpha-fetoprotein in the blood, which was markedly elevated prior to surgery, returned to a normal level postoperatively. Hepatoblastoma with the combination of features described above has not been previously reported. Because of the two striking and easily recognizable features viz. total lack of differentiation of tumor cells and presence of abundant mucoid material, the authors designated the tumor as mucoid anaplastic hepatoblastoma.

Carcinoma, Hepatocellular↗
PubMed1984

Sister-chromatid exchanges and chromosome aberrations in lymphocytes from monkeys exposed to ethylene oxide and propylene oxide by inhalation.

The ability of long-term exposures to inhaled ethylene oxide (EO) and propylene oxide (PO) to induce sister-chromatid exchanges (SCEs) and chromosome aberrations in peripheral lymphocytes of monkeys was investigated. Five groups of adult male cynomolgus monkeys were exposed at 0 (shared control), 50, or 100 ppm EO, and at 100 or 300 ppm PO (7 hr/day, 5 days/week) for 2 years. EO exposures at 50 and 100 ppm resulted in statistically significant increases in sister-chromatid exchange rates and in the incidence of chromosome aberrations in monkey lymphocytes. Both EO-exposed groups had increased numbers of SCEs/metaphase compared to controls, with the SCEs/metaphase of the EO 100 ppm group also significantly elevated versus the EO 50 ppm group. Variability of SCEs/metaphase within each monkey increased even more than the increase in total SCEs/metaphase group with increasing EO exposure. Chromatid-type aberrations were also significantly increased for both EO 50 and EO 100 ppm groups compared to controls. Statistically significant increases in the number of chromosome-type aberrations (excluding gaps) were found only in the EO 100 ppm group. Combined chromatid- and chromosome-type aberrations were increased in both EO 50 and EO 100 ppm groups. No group differences in the number of gaps were found. In lymphocytes from monkeys exposed at 100 and 300 ppm PO, there were no group differences compared to controls for any variable-chromatid or chromosome-type aberrations, gaps, or SCEs/metaphase. These results indicate that EO is a more potent clastogen than PO and demonstrate, for the first time, statistically significant effects of EO on both SCEs and chromosome aberrations in lymphocytes of nonhuman primates.

Animals↗
PubMed1983

Sequential bilateral nephroblastic tumors of different cell types in an infant. Possible effect of chemotherapy versus de novo origin.

A 14-month-old infant had a classical Wilms' tumor of the left kidney and subsequently developed a tumor showing predominantly mature mesenchymal elements and lack of cellular atypia in the right kidney. His father had classical Wilms' tumor of the left kidney. The various possibilities regarding the precise nature and mechanism of the development of the tumor in the right kidney are discussed. The similarities and the differences between this tumor and congenital mesoblastic nephroma are noted. The possible relation of chemotherapy to mesenchymal differentiation and maturation in Wilms' tumor is considered. The possibility of an unusual, histologically benign, mesenchymal variant in the spectrum of infantile nephroblastic neoplasia is also suggested.

Age Factors↗
PubMed1983

Follicular growth and kinetics during the estrous cycle, pregnancy and postpartum in the Indian mole rat (Bandicota bengalensis).

Follicular growth and kinetics were studied in detail in the ovaries of the Indian mole rat (Bandicota bengalensis) during various stages of the estrous cycle; days 7, 12, 15, 19, and 21 of pregnancy; and day 2 postpartum. The sizes of follicles, oocytes, nuclei, and nucleoli were measured. In all rats, regression coefficients, a, and intercepts, b, were calculated in oocyte/follicle, oocyte nucleus/follicle and oocyte nucleus/oocyte regressions. The oocyte reached its maximum size when the average follicle diameter was 117 microns in nonpregnant rats and 131 microns in pregnant rats. The oocyte nucleus attained maximum size when the follicle diameter was 110 microns during the estrous cycle and 111 microns during pregnancy and postpartum. Maximum values of the diameter of the largest antral follicle and average diameter of the four largest antral follicles were observed during proestrus (473 and 442 microns, respectively) and on day 21 of pregnancy (611 and 538 microns, respectively). Chi 2 analysis showed that distribution of various types of follicles was not independent of the stage of the estrous cycle and pregnancy. In estrus and metestrus most of the follicles were between stages I and V. However, by diestrus and proestrus, follicles of all size groups developed. The numbers of stage I and II follicles did not differ as pregnancy advanced. More stage V follicles were present on day 12 than on day 7 of pregnancy; however, their numbers decreased by day 15. Afterwards, progressive increase of stage V and (VI + VII) follicles was observed until day 21. This was accompanied by the shift of follicles from stage (III + IV) on days 19 and 21 of pregnancy and even of stage II on day 2 postpartum. Wherever possible, the results have been compared with previous observations in various rodent species.

Animals↗