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Biomedical subjects

R C Jones

Publications and source records attributed to R C Jones.

At least 199 records · Page 11Linked to original sources
PubMed1979

Reversal of the anti-implantational effect of luteinizing hormone-releasing hormone (LRH) by estradiol-17 beta and progesterone, alone and in sequence.

The use of estradiol-17 beta and progesterone, alone or in sequence, to reverse the anti-implantational effect of 100 and 500 micrograms LRH has been studied. Sequential administration of the steroids was most efficacious in reversing the effect of 100 micrograms while progesterone alone proved to be the only treatment inhibiting the effect of 500 micrograms LRH. A possible difference in mechanism of action of the two doses of LRH is discussed.

Animals↗
PubMed1979

Local antifertility effect of luteinizing hormone-releasing hormone (LRH).

Injection of luteinizing hormone-releasing hormone (LRH) into the right uterine horn of the rat on D5 produced a dose related inhibition of pregnancy in the treated horn. The number of viable fetuses as well as the uterine weight was reduced while the number of placental sites was increased. The contralateral uninjected horn was unaffected. These data demonstrate that LRH can inhibit pregnancy in the rat through an extrapituitary effect.

Animals↗
PubMed1979

The fate of fertilized ova in rats receiving luteinizing hormone-releasing hormone (LRH).

The development and eventual fate of unimplanted fertilized ova in rats receiving pregnancy-inhibiting doses of luteinizing hormone-releasing hormone (LRH) were studied during the first 14 days of gestation. The results suggest that LRH accelerates passage of ova through the oviducts. Also, the zona pellucida of treated animals is retained by the majority of ova until day 7; zona-encased ova were observed as late as day 10. Elimination of the ova appears to occur by expulsion with uterine fluids through the vagina upon the animals' return to estrus.

Animals↗
PubMed1979

The effects of cooling to 5 degrees C and freezing and thawing on the ultrastructure of bull spermatozoa.

Semen from 6 bulls was examined under the transmission electron microscope immediately after collection, after dilution and cooling to 5 degrees C and after freezing and thawing. Conception rates were determined following artificial insemination of the frozen and thawed semen. Dilution and cooling to 5 degrees C caused acrosomal swelling in about 50% of the spermatozoa. Subsequent freezing and thawing caused considerable ultrastructural changes to the acrosomes (disruption of the plasma and outer acrosomal membranes and dispersion of the acrosomal contents) and middle pieces (breakage of the plasma membrane and a reduction in the electron density of the mitochondrial matrix) of a high proportion of spermatozoa. The average non-return rate following insemination of semen from 5 of the bulls was 61.6% and higher (P greater than 0.001) than for the sixth bull (15%). Although this difference in semen viability was also demonstrated in the structural studies (acrosome, P greater than 0.05: middle piece, P greater than 0.001), more work is required to assess the relationship between structure and function of spermatozoa.

Animals↗
PubMed1979

The biological activities of norgestrel and its enantiomers.

The dextrorotatory enantiomer of norgestrel has now been tested by oral and parenteral routes in a broad range of biological assays and its inactivity has been confirmed. The active enantiomer has been further compared with the racemate in a similarly broad range of tests, largely by the oral route. Levonorgestrel was twice as potent as the racemate in experiments in which norgestrel was effective. These data reinforce earlier findings that levonorgestrel is responsible for all the biological activity found in norgestrel.

Administration, Oral↗
PubMed1978

Staging laparotomy in Hodgkin's disease.

Staging laparotomy was performed at the University of Virginia Medical Center on 111 patients with Hodgkin's disease. The operation included multiple liver and lymph node biopsies and, excepting three patients, splenectomy. The histopathology was reviewed and the 111 patients were classified as follows: nodular sclerosis, 74; mixed cellularity, 28; lymphocyte predominance, 7; and undetermined, 2. There were no deaths. Wound, pulmonary or urinary tract complications occurred in 11 patients. One case of postoperative thrombophlebitis occurred and in another case small bowel obstruction developed, and resolved without reoperation. The pathologic stage (PS) following laparotomy was unchanged from the clinical stage (CS) in 64%, reduced in 20%, and advanced in 16%. The therapy, however, was altered in 38% of the patients. Lymphangiography in 103 patients was interpreted as showing lymph node involvement in 38, equivocal involvement in 11, and no involvement in 54. Among the 92 examinations reported as either positive or negative, 77% were confirmed histopathologically, 21% were falsely positive, and 2% were falsely negative. The spleen was positive for Hodgkin's disease in 39% of cases, and in these patients with positive spleens there was no reason to suspect intra-abdominal involvement preoperatively in 21%.

Abdominal Neoplasms↗
PubMed1978

Management of pancreatic trauma.

Since 1950, 300 patients sustaining pancreatic injuries have been managed. Three-fourths of the injuries were due to penetrating trauma with a 20% mortality and one-fourth due to blunt trauma resulting in an 18% mortality. The pancreatic injury was responsible for death in only 3% of patients. Early onset of shock resulted in 38% mortality whereas only 4% of normotensive patients died. No patient died of an isolated pancreatic injury. Sepsis was the second most common cause of death following hemorrhage. Preoperative serum amylase was elevated more frequently following blunt trauma than penetrating trauma, but did not correlate with injury. There has been a tendency toward more frequent use of distal pancreatectomy for simple penetrating injuries without obvious ductal violation which increases operative time, blood loss and possible intra-abdominal abscess since resection usually requires splenectomy. Patients considered for an 80% distal resection are better managed with a Roux-en-Y limb to the distal pancreas since three patients developed diabetes following an 80% or greater resection. A conservative approach consisting of Penrose and sump drainage is adequate for most injuries.

Abdominal Injuries↗
PubMed1978

The effects of glycerol on the metabolism and ultrastructure of boar spermatozoa.

Cooling diluted boar semen to 5 degrees C and the addition of glycerol at 20 degrees C and 5 degrees C all depressed the subsequent metabolism of glucose, but had no effect on total oxygen uptake or lactate production. Ultrastructural studies showed that although glycerol had no effect on middle-piece cytology, it increased the incidence of acrosomal vesiculation at 5 degrees C. It is concluded that acrosomal vesiculation does not affect the metabolism of spermatozoa and it is suggested that the reported detrimental effect of glycerol on the fertilizing capacity of spermatozoa is related to its membrane activity.

Animals↗
PubMed1977

Properties of the cell envelope and a cell-envelope protein of Pseudomonas facilis.

The molecular weight of the protein moiety of a phospholipoprotein complex isolated from Pseudomonas facilis has been examined with a variety of sodium dodecylsulfate-polyacrylamide gel electrophoretic systems. A molecular weight of 35 000 was determined for the protein in all analyses. A 35 000-dalton protein was present in the EDTA extract of P. facilis and in the cytoplasmic and outer membrane fractions, but not in the lipopolysaccharide and peptidoglycan. Prior inoculation of mice with the phospholipoprotein complex led to a 7.5- to 15-fold increase in the LD50 when mice were subsequently inoculated with Salmonella typhimurium; this pathogen has a cell-surface protein which cross-reacts immunologically with antibody to the P. facilis phospholipoprotein complex.

Animals↗
PubMed1977

Administration of anti-inflammatory compounds in silastic capsules.

Eleven compounds, within hollow capsules of polydimethylsiloxane (Silastic), have been studied with regard to their rate of release and anti-inflammatory activity in the Adjuvant Arthritic (AA) rat. All of the compounds diffused through the capsule wall to some extent with cortisone acetate exhibiting the slowest and ibuprofen the fastest release rate. Of the eleven encapsulated compounds, only phenylbutazone, indomethacin, ibuprofen and naproxen significantly reduced right and left paw volume below that of control value. Silastic encapsulation increases efficacy of phenylbutazone and indomethacin two to three times over subcutaneous or oral administration. Based on potency and duration of constant release, indomethacin and naproxen should exhibit anti-inflammatory activity in excess of 12 months.

Administration, Oral↗