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Biomedical subjects

S A Murray

Publications and source records attributed to S A Murray.

69 records · Page 4Linked to original sources
PubMed1984

Multiparameter morphology as a means of specifically identifying hormone stimulated adrenal cortical tumor cells (Y-1) and granulosa cells in coculture.

In order to test for biologically valid, direct communication between mouse adrenal tumor and porcine ovarian granulosa cells a method was needed for distinguishing the two cell types in culture. To this end granulosa cells were cultured for 24-48 hours after which they were challenged with rhodamine conjugated latex beads for 30 minutes to 24 hours in monolayer culture. When phagocytosis was allowed to occur for longer than one hour the phagocytic vesicles containing the conjugated beads appeared to fuse with each other and with digestive vacuoles. The resultant vesicles contained many beads and were located within the cell body close to the nucleus. At shorter incubation periods, beads were observed predominantly in the periphery of the cell. Y-1 adrenal cortical tumor cells failed to ingest beads and could be distinguished from the bead labeled granulosa cell in coculture with scanning or thin section electron microscopic as well as fluorescence microscopic techniques. Gap junctions were observed between heterotypic cell pairs; however, no evidence of cell fusion was found. ACTH stimulated granulosa: Y-1 adrenal cocultures initiated cAMP-dependent kinase dissociation in the Y-1 cells and in contacting granulosa cells identified positively by the presence of the beads. We have used the bead labeling technique and a procedure for following the kinetics of cAMP-dependent protein kinase dissociation in order to follow the specific hormonal stimulation of these heterotypic cells in coculture.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Neoplasms↗
PubMed1982

Predictive value of surveillance skin cultures in total-parenteral-nutrition-related infection.

To assess the importance of skin flora in the pathogenesis of infection complicating total parenteral nutrition and the predictive value of positive skin cultures for the development of infection 54 patients, who received 59 courses of total parenteral nutrition, were followed up. Three times per week, at the time of dressing and line changes, the skin at the site of insertion of the cannula was swabbed for culture. Results of skin cultures were compared with results of semiquantitative culture of the proximal intravascular portion of the cannula. Infected patients were defined as those having cannula cultures with greater than or equal to 15 colonies or those with primary septicaemia. 21 of 59 courses (36%) were associated with positive skin cultures; 14 of these 21 courses were associated with cannula infection, 2 with bacteraemia or fungaemia, and 12 with local infection. 38 of 59 (64%) courses had sterile skin cultures; in none of these 38 patients did infection develop (p less than 0.001). Skin colonisation was associated with otherwise unexplained fever (11 of 21 with positive skin culture versus 5 of 38 with negative skin culture, p less than 0.001), inflammation at the insertion site (13 of 21 versus 10 of 38, p less than 0.05), and violations of line protocol (11 of 21 versus 10 of 38, p less than 0.05). The absence of any organism on the skin had a negative predictive value of 98%, whereas the presence of an organism on the skin had a positive predictive value of 61%. Skin culture thus seems able to identify which patients receiving parenteral nutrition are at high risk of infection.

Adult↗
PubMed1982

Total parenteral nutrition-related infections. Prospective epidemiologic study using semiquantitative methods.

Studies of total parenteral nutrition-related infection have incorrectly relied on positive results on culture of the cannula tip to confirm the source. We undertook a prospective study of total parenteral nutrition-related infections in adult patients by obtaining blood from all total parenteral nutrition lines for pour-plate culture twice weekly and culturing intravascular line segments by the technique of Maki. Twelve of 100 courses of total parenteral nutrition (12 percent) in 69 patients resulted in infections--five (5.0 percent) had sepsis, and seven (7.0 percent) had local infection. In five of these 12, pour-plate culture gave positive results (five of 38 pour plates) with counts of 8 colony-forming units per ml (cfu/ml) for Candida tropicalis, and 25 to more than 1,000 for bacterial isolates. In nine of 12, culture of the intravascular line segment gave positive results with more than 50 cfu/ml. Pathogens isolated from intravascular line segments included Staphylococcus epidermidis (three cases), Candida species (three cases), Staphylococcus aureus (two cases), Serratia marcescens (one case) and mixed bacterial pathogens (one case). In contrast, pour-plate culture gave positive results in only seven of 88 uninfected (control) courses (318 pour plates), and culture of intravascular line segments gave positive results in two of 65 uninfected courses (p less than 0.001). No differences existed among patients with and without infection with regard to age, underlying disease, surgery, systemic antibiotic usage, or the presence of other infections. The duration of total parenteral nutrition was longer in courses without infection than in courses with infection (14.7 +/- 9.4 days versus 11.0 +/- 4.0 days; p less than 0.02). In six of 12 courses with infection, the line had been violated compared with 22 of 88 courses without infection (p less than 0.001). T-connectors for the centra administration of intralipid were associatd with infection (p less than 0.02). The value of routine pour-plate culture was illustrated in three courses in which the positive pour-plate culture results antedated positive blood culture results or line removal.

Bacterial Infections↗
PubMed1981

Gap junction assembly and endocytosis correlated with patterns of growth in a cultured adrenocortical tumor cell (SW-13).

After seeding at subconfluent densities, human adrenocortical adenocarcinoma cells (SW-13) proliferate to form a typical epithelial monolayer upon the culture vessel substratum. Single cells of the confluent monolayer are spontaneously released into the medium, however, where they may remain isolated or reaggregate with other floating cells. In this study, we examined the growth patterns of these cells in culture and analyzed alterations of their most prominent intercellular contact specialization, the gap junction, as cellular relationship changed during growth and development of the cell culture. We report here details of gap junction assembly during cellular aggregation and correlate the apparent endocytosis of gap junctions with the spontaneous release of single cells from the monolayer into the medium.

Adenocarcinoma↗
PubMed1980

Effects of loading density on catfish blood.

Results from this study indicate that a fish density stress syndrome exists for red blood cell morphology. Smaller (by 3.5%) and rounder (by 0.6%) red blood cells were consistently found in intensive fish cultures.

Animals↗
PubMed1979

Evidence for the participation of actin microfilaments and bristle coats in the internalization of gap junction membrane.

Thin sections of rabbit granulosa, human SW-13 adrenal cortical adenocarcinoma, and mouse B-16 melanoma cells revealed an apparent single-layered basket of 4- to 7-nm filaments surrounding cytoplasmic gap junction vesicles. This interpretation was based upon apparent longitudinal, cross, and en face sections of structures surrounding the vesicle profiles in tissue treated with tannic acid-glutaraldehyde. In granulosa cells incubated with the S-1 fragment of heavy meromyosin, arrowhead-decorated filaments were observed at the periphery of the gap junction vesicles, suggesting that these filaments contained actin. In addition, we found that small gap junctional blebs and vesicles at the cell surface were coated with short electron-dense bristles similar in appearance to the cloathrin-containing coat of coated vesicles of nonjunctional membrane. The role of these and other cytoskeletal elements in the possible endocytosis of gap junction membrane is discussed.

Actins↗
PubMed1978

Gap junctions and ACTH sensitivity in Y-1 adrenal tumor cells.

Initial studies of adrenocorticotropin-sensitivity (ACTH-sensitive) and ACTH-insensitive Y-1 adrenal cortical tumor cell lines suggest a relationship between responsiveness to ACTH and the presence of gap junctions. An ACTH-sensitive clone of Y-1 cells possesses gap junctions and these junctions appear to enlarge with ACTH treatment. GAP junctions have not been observed, however, in an ACTH-insensitive clone of Y-1 tumor cells even when stimulated to produce cyclic adenosine monophosphate and steroids with cholera toxin.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

Investigation of an epidemic of multi-drug resistant Pseudomonas aeruginosa.

Inter- and intrahospital epidemics of nosocomial infections due to gram-negative bacilli resistant to many antimicrobials have been well-documented. Prospective studies on the use of isolation along with epidemiologic analysis and appropriate environmental control have been lacking. In the six-month period from November 1978 to April 1979 Pseudomonas aeruginosa (MDR) resistant to all antibiotics except amikacin was isolated from 15 patients. This organism had not previously been seen in our hospital. Epidemiologic assessment of infected patients revealed that nine of 15 patients had contact either with a previously infected case or contaminated area. All strains of P. aeruginosa were identical by pyocin typing and antibiogram. The organism was present in an environmental reservoir, the urine graduated cylinder, and was found in three of eight receptacles (p = 0.002 vs. other environmental cultures). A case control study of patient risk factors showed aminoglycoside use, other antibiotic use, surgery, intravenous lines, Foley catheter use and mechanical ventilation to be no more frequent in cases than controls. The use of aminoglycosides in only 40% of cases suggests that antibiotic pressure was not the sole factor in perpetuating the epidemic.

Aminoglycosides↗
PubMedDate not supplied

Modulation of adrenal gap junction expression.

To increase our knowledge of the role of peptide hormone stimulation in gap junction protein expression and adrenal cortical cell function, primary rat adrenal cortical cells were treated with adrenocorticotropin, and gap junction proteins were measured. Immunocytochemistry and western blot analysis were used to detect and characterize gap junction type and distribution. The gap junction protein, connexin 43 (alpha 1), was detected. Analysis of six connexin protein types did not reveal gap junction species other than alpha 1. Cells of the inner adrenal cortical zones, zonae fasciculata and reticularis, were demonstrated to have the highest number of gap junctions per cell in the adrenal gland. Adrenal cell cultures enriched for the two inner cortical adrenal zones were established and demonstrated also to express alpha 1 gap junction protein. Adrenocorticotropin (40 mUnits/ml) and dibutyryl cyclic adenosine monophosphate (1 mM) treatments increased alpha 1 gap junction protein levels and decreased cell proliferation rates in the cell cultures. The results are consistent with the hypothesis that gap junction expression can be regulated by adrenocorticotropin acting through the second messenger cyclic adenosine monophosphate. It can be suggested that gap junction expression in the adrenal gland may be under hormonal influence, and that gap junctions serve as passage for movement of molecules involved in control of cell proliferation.

Adrenal Glands↗
PubMedDate not supplied

Characterization of gap junction expression in the adrenal gland.

To characterize the presence of gap junctions in adrenal tissue we used immunohistochemical analysis of connexin expression in whole adrenal glands and in primary rat adrenal cortical cell cultures. alpha 1 (connexin 43) gap junction protein was demonstrated in rat adrenal glands and in primary adrenal cell cultures. The alpha 1 gap junction proteins were present in different amounts such that little or no alpha 1 antigen was detected in the zona glomerulosa (ZG), while cells of the zona fasciculata (ZF) and zona reticularis (ZR) stained intensely. There was an inverse relationship between cell division rate and gap junction number in the intact adrenal gland. We placed the cells from the most intensely staining areas (ZF/ZR) of the rat adrenal cortex into culture. These primary adrenal cells expressed alpha 1 gap junction antigen on their cell surfaces in regions of cell-cell contact. ACTH (40mU/ml) treatment resulted in an increase in gap junction expression relative to controls in primary rat adrenal cultures. These results indicate that the abundance of gap junction expression is differential in the cortical zones and can be modulated by hormonal stimulation. These observations are also thought to reflect morphological and functional differences in adrenal cortical zones.

Adrenal Glands↗