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Biomedical subjects

R Jensen

Publications and source records attributed to R Jensen.

At least 163 records · Page 9Linked to original sources
PubMed1987

A prospective, controlled study of prophylactic drainage after colonic anastomoses.

A prospective, randomized, controlled trial was designed to study the influence of a corrugated latex drain on anastomotic integrity, wound infection, and respiratory complications after elective colonic resections above the pelvic peritoneum. Sixty patients entered the trial; 28 were drained and 32 undrained. Three patients in the undrained group died soon after surgery of causes unrelated to their colon anastomoses. There were no other differences in the incidence of postoperative complications in the two groups. When an anastomosis leaked, neither feces nor pus emerged via the drain. It is concluded that while the drains did not increase the incidence of postoperative complications, neither did they accomplish the purpose for which they were inserted. If, in addition, the economic cost of drainage is considered, it would seem that there is no advantage in inserting prophylactic drains after colonic anastomoses and their routine use needs to be reconsidered.

Adult↗
PubMed1987

Rat astrocytes and Schwann cells in culture synthesize nerve growth factor-like neurite-promoting factors.

Neurite-promoting activity in feeding medium conditioned by rat astrocytes and Schwann cells in culture was examined. The conditioned medium (CM) from both types of glial cultures stimulated extensive neurite outgrowth from embryonic chick dorsal root ganglia (DRG) as well as pheochromocytoma (PC12) cells. Both the DRG and PC12 cells also produce neurite outgrowth in the presence of nerve growth factor (NGF). With the DRG, the neurite growth rates observed with the glial cell CM were identical to growth rates seen with NGF. Although anti-NGF antibody did not inhibit the neurite outgrowth produced by either of the glial CM, a nerve growth factor radioreceptor assay did detect an NGF-like molecule in both CM. Since the extensive neurite outgrowth stimulated by the glial CM was not mimicked by pure laminin alone, we conclude that the glial neurite promoting factors are distinct from laminin.

Adrenal Gland Neoplasms↗
PubMed1987

Comparison of acute toxicities of deoxynivalenol (vomitoxin) and 15-acetyldeoxynivalenol in the B6C3F1 mouse.

The acute toxic effects of deoxynivalenol (DON) and 15-acetyldeoxynivalenol (15-ADON) were compared in the B6C3F1 female mouse after oral and intraperitoneal exposure. Using the abbreviated procedure of Lorke (Archs Toxicol. 1983, 54, 275), LD50 values for DON were estimated to be 78 mg/kg (oral) and 49 mg/kg (ip) whereas the LD50 values for 15-ADON were 34 mg/kg (oral) and 113 mg/kg (ip). Acute doses of these toxins resulted in extensive necrosis of the gastro-intestinal tract, bone marrow and lymphoid tissues, and focal lesions in kidney and cardiac tissue. The minimum doses required for these histopathological effects were consistent with LD50 estimations. The results indicate that 15-ADON was more or less toxic than DON depending on the route of administration. Risk assessments for DON should therefore consider the potential for 15-ADON occurrence and toxicity in food and feed.

Animals↗
PubMed1987

Arogenate dehydratase.

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Chromatography, DEAE-Cellulose↗
PubMed1986

Plasma prostaglandins: 6-keto-PGF1 alpha, TXB2 and PGE2 in juvenile-onset diabetes determined by high-pressure liquid chromatography and radio-immunoassay.

Some studies have recently reported increased production of platelet thromboxane and decreased vascular prostacyclin in patients with diabetes mellitus. The impact of these changes on platelet and vascular functions in vivo is still speculative. Using radio-immunoassay and high pressure liquid chromatography we have studied the plasma levels of 6-keto-PGF1 alpha, TXB2 and PGE2 in 23 juvenile-onset diabetics. There was no significant difference in these plasma prostaglandins between the diabetics and a control group. The prostaglandins were neither correlated to blood-glucose nor the degree of glycosylation (HbA1c). Our results can not support the hypothesis that decreased vascular prostacyclin and increased platelet production of TXB2 are important factors in diabetic patients.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

Effects of 8-week exposure of the B6C3F1 mouse to dietary deoxynivalenol (vomitoxin) and zearalenone.

Weanling female B6C3F1 mice were fed semi-purified diets containing 0, 0.5, 2.0, 5.0, 10.0 or 25.0 ppm (mg/kg) deoxynivalenol (DON) over 8 wk and were assessed for effects on feed intake, body-weight gain, terminal organ weights, histopathology, haematology and serum immunoglobulin levels. To determine whether DON effects were potentiated by the oestrogen zearalenone (ZEA), a mycotoxin frequently found to occur with DON in cereals, two additional groups of mice were fed diets containing either 10 ppm ZEA or 10 ppm ZEA plus 5 ppm DON. The rate of body-weight gain was significantly reduced (P less than 0.01) for all mice consuming feed containing 2.0 ppm or more of DON, whereas only the mice ingesting the diet containing 25 ppm DON showed a significantly decreased (P less than 0.01) rate of feed consumption. Gross and histopathological evaluation of thymus, spleen, liver, kidney, uterus, small intestine, colon, heart, brain, lungs and bone marrow from control and all mycotoxin-exposed mice revealed that these tissues were normal in appearance and in histological architecture. DON-amended diets did however, cause dose-dependent decreases in the terminal organ weights recorded (thymus, spleen, liver, kidney and brain). In the DON-treated groups, statistically significant dose-dependent decreases in the counts of total circulating white blood cells were associated with an increase in polymorphonuclear neutrophils and a decrease in lymphocytes and monocytes. Dietary DON caused a dose-dependent decrease in serum IgM but, in contrast, a dose-dependent increase in serum IgA. In none of the above instances was 10 ppm ZEA shown to act synergistically or antagonistically with 5 ppm DON. Since dietary DON at levels as low as 2.0 ppm exerted significant effects on the growing B6C3F1 female mouse, future approaches should include studies of the mechanisms by which this mycotoxin affects nutrient utilization and modifies the normal immune response.

Animals↗
PubMed1986

Structure of the Saccharomyces cerevisiae HO gene and analysis of its upstream regulatory region.

The HO gene product of Saccharomyces cerevisiae is a site-specific endonuclease that initiates mating type interconversion. We have determined the nucleotide sequence of a 3,129-base-pair (bp) segment containing HO. The segment contains a single long open reading frame encoding a polypeptide of 586 amino acids, which has unusual (unbiased) codon usage and is preceded by 762 bp of upstream region. The predicted HO protein is basic (16% lysine and arginine) and is calculated to have a secondary structure that is 30% helical. The corresponding transcript is initiated approximately 50 nucleotides prior to the presumed initiation codon. Insertion of an Escherichia coli lacZ gene fragment into the putative HO coding segment inactivated HO and formed a hybrid HO-lacZ gene whose beta-galactosidase activity was regulated by the mating type locus in the same manner as HO (repressed by a 1-alpha 2). Upstream regions of 1,360 and 762 bp conferred strong repression; 436 bp led to partial constitutivity and 301 bp to full constitutivity. Thus, DNA sequences that confer repression of HO by a1-alpha 2 are at least 250 nucleotides upstream of the transcription start point and are within 436 nucleotides of the HO initiation codon. The progressive loss of repression suggests that both the -762 to -436 and the -436 to -301 intervals contain sites for regulation by a1-alpha 2. The HO gene contains two distinct regions that promote autonomous replication of plasmids in S. cerevisiae. These regions contain sequences that are homologous to the two conserved sequences that are associated with ARS activity.

Amino Acid Sequence↗
PubMed1986

[Influence of calcic and magnesic sulphurous thermal water on the metabolism of lipoproteins in the rat].

We have studied in rats fed hypercholesterolemic diet the action of calcic and magnesic sulphurous water from Capvern on the modification of the lipoproteins metabolism caused by hypercholesterolemia. The rats subjected to a hypercholesterolemic diet with thermal water of Capvern was found to have a plasma level of cholesterol significantly less increased (P less than 0.01) compared to those subjected to the same diet with ordinary drinking water (25%). We demonstrated after 105 days of experimentation on tested rats that thermal water may affect the cholesterol catabolism by increased level of cholesterol HDL (52%) and stabilizing level of cholesterol LDL comparatively to the controls. These data suggest that the thermal water from Capvern enhanced the transformation of cholesterol to biliary acids and their biliary secretion. A possible relationship between the influence of the thermal water and the metabolism of lipoproteins would be explained by a possible increase of hepatic receptors which identify apolipoproteins B (LDL) and E (HDLc) on cholesterol fed rats, suggesting a great synthesis of nascent apolipoproteins HDL which are antiatherogenic.

Animals↗
PubMed1986

Cholecystokinin-8 stimulates adrenocorticotropin release from anterior pituitary cells.

Cholecystokinin octapeptide (CCK-8) stimulated adrenocorticotropin hormone (ACTH) release from both rat anterior pituitary cells in culture and a tumor cell line of the mouse anterior pituitary (AtT-20/D16-16). The stimulation of ACTH release was dependent on the time of exposure to CCK-8 and the concentration of this peptide applied to anterior pituitary cells. Cerulein evoked ACTH release whereas human gastrin 1, CCK-4 and desulfated CCK-8 only produced minimal affects on ACTH release at concentrations of 10(-4) M. In contrast, these latter three peptides were as effective as CCK-8 in inducing the secretion of amylase from pancreatic acinar cells. Antagonists of CCK-8 receptors in the pancreas such as proglumide, benzotript and dibutyryl cyclic GMP did not affect the ACTH release response to CCK-8. The CCK-8 stimulation of ACTH release was calcium-dependent and blocked by glucocorticoid pretreatment. The mechanisms by which CCK-8 evoked ACTH release appears distinct from that of other ACTH secretagogues such as corticotropin releasing factor and vasopressin. The data suggest that CCK-8 is a corticotropin releasing factor-like agent acting through a putative novel receptor subtype in the anterior pituitary.

Adrenocorticotropic Hormone↗
PubMed1986

Eosinophilic myositis and muscular sarcocystosis in the carcasses of slaughtered cattle and lambs.

Fifty-three bovine and 7 ovine carcasses condemned for having eosinophilic myositis were evaluated. Four (7.3%) of the bovine carcasses had a few, large local lesions in skeletal muscles (category A), and 49 (92.7%) of the bovine carcasses and 7 (100%) of the ovine carcasses had multiple, small, disseminated lesions in tongue, esophagus, heart, diaphragm, or skeletal muscles (category B). Tissue from carcasses of category B were evaluated for bacteria, viruses, selenium, and pathologic changes. Pathogenic bacteria and viruses were not isolated and selenium concentrations were normal. In category B, all carcasses had granulomas; of the 49 bovine carcasses and 7 ovine carcasses, 38 (77.6%) and 7 (100%), respectively, had one or more granulomas with opened dead sarcocysts. The data indicated that opened sarcocysts killed the host myocyte and adjacent myocytes and stroma, thereby initiating granuloma formation.

Animals↗
PubMed1986

Clinical significance and etiology of infected catheters used for total parenteral nutrition.

Catheter related sepsis (CRS) is the most serious complication of total parenteral nutrition. Frequently, however, low rates of CRS are associated with a high incidence of infection of the catheter tip, the clinical significance of which is unclear. The relationships between CRS, infection of the catheter tip and infection at the site of catheter insertion have been investigated in 283 catheters of 257 patients receiving total parenteral nutrition. CRS occurred in only ten patients (3.5 per cent) whereas organisms were isolated from 108 catheter tips (38.2 per cent). The most common organism isolated was Staphylococcus epidermidis (66.7 per cent). Eight catheter tips were colonized from a distant septic focus. Organisms were isolated from 90 catheter tips which were removed electively from patients who displayed no clinical evidence of sepsis. There was a poor correlation between infected catheter tips and infected catheter insertion sites. Asymptomatic infection of the catheter tip appears to be of little clinical relevance, resulting in no patient morbidity. Contamination of the catheter tip during or after removal seems to account for a significant proportion of these infections.

Bacteria↗