Search PubMed⌕ Search

Biomedical subjects

S C Jacobs

Publications and source records attributed to S C Jacobs.

12 recordsLinked to original sources
PubMed1992

Enhanced neurovirulence of tick-borne orbiviruses resulting from genetic modulation.

The genome of orbiviruses (Reoviridae family) comprises 10 segments of double-stranded RNA. The fourth largest segment of the tick-borne Kemerovo (KEM) group orbiviruses is the genetic determinant of neurovirulence in experimentally infected mice, and segment 6 determines serotype. Reassortant viruses derived from a cross between two KEM-related viruses, Great Island (GI) and Wexford (WEX), that had the heterotypic gene combination W4G6 (segment 4 of WEX virus and segment 6 from GI virus) were nonpathogenic in mice. This apparent genetic modulation of neurovirulence may have resulted from steric interaction between the two outer capsid proteins of nonpathogenic reassortants. Further data are consistent with this hypothesis. Reassortants generated from additional KEM group viruses showed various degrees of enhanced neurovirulence in terms of their PFU/LD50 (ratio of infectivity in cell culture and in mice) and ASTmax (the average survival time at the highest virus dilution resulting in 100% mortality). Some reassortants were more pathogenic than either of their parental viruses. The results indicate that the gene determining neurovirulence dictates ASTmax, and the PFU/LD50 is a measure of the interaction between the products of the gene determining neurovirulence and that determining serotype. The nonpathogenic phenotype of a low passage isolate (St. Abb's 84-34 virus), derived from a single tick, generated neurovirulent reassortants. This result indicates that genetic modulation of KEM group viruses may occur in nature.

Animals↗
PubMed1979

Examination of peripheral nerves with the scanning electron microscope.

The theoretical applications and advantages of the scanning microscope in peripheral nerve research are presented. The internal anatomy of the peripheral nerve can be distinctly examined, and long segments of axons can be examined without the necessity of tedious study of multiple sections. The SEM should make it possible to more readily study the migration of axon sprouts across a repair site. New concepts in teaching and research may develop from the use of this excellent tool.

Animals↗
PubMed1979

Prostatic osteoblastic factor.

Cell cultures of fetal rat osteoblasts and organ cultures of fetal rat calvaria were used to study the effects of extracts of prostatic tissue on bone cell growth. Extracts of bening prostatic hyperplasia, but not an undifferentiated prostatic carcinoma, stimulated the incorporation of 3H-thymidine and 14C-proline into fetal rat osteoblasts, calvaria, and skin fibroblasts. Extracts of well-differentiated prostatic cancer and normal postpubertal prostate also stimulated 3H-thymidine incorporation by fibroblasts. These findings support the hypothesis that a potentially unique factor found in prostatic tissue induces the osteoblastic response of bone to metastatic prostatic cancer.

Adenocarcinoma↗
PubMed1978

Complications of permanent bladder catheter drainage in spinal cord injury patients.

We reviewed the effect of permanent bladder catheter drainage on the course of 59 long-term spinal cord injury patients. Current renal function, findings on excretory urography and major renal, bladder, genital and urethral complications were tabulated. Although all long-term spinal cord injury patients had severe renal function, depression and abnormal excretory urograms patients with indwelling bladder catheters had a significantly higher complication rate than those managed without an indwelling catheter.

Adult↗
PubMed1977

Effects of immunosuppression on the rejection of methylcholanthrene tumor isografts.

The effect of immunosuppression with azathioprine, methylprednisolone, or both, on primary and secondary immune responses to a transplanted tumor was studied. The ability to reject a methylcholanthrene-induced squamous cell carcinoma of the prostate in Lewis rats was determined by rechallenge with tumor cells after amputation of the primary transplant. Oral azathioprine (20 mg/kg/day) increased the incidence of tumors in a primary challenge, but did not affect the ability of immunized rats to reject subsequent tumor isografts. Similar results were obtained with 2 mg/kg day intraperitoneal (IP) azathioprine, 2 mg/kg IP methylprednisolone, and the combination of 2 mg/kg/day IP methylprednisolone and 10 mg/kg/day IP azathioprine. It appears that immunosuppression by azathioprine affects the proliferation of sensitized cells during the immunological response to antigens of this specific tumor. Immunosuppression does not appear to alter substantially the processing of tumor-specific antigens or the cytotoxic effectiveness of the immune system. This data is reassuring to the concern of whether transplantation in patients previously cured of cancer is safe.

Animals↗
PubMed1977

Bladder cancer and squamous metaplasia in spinal cord injury patients.

The influence of long-term indwelling urethral catheterization was studied by random bladder and urethral biopsies in 62 spinal cord injury patients. Six patients (10 per cent) had diffuse squamous cell bladder carcinoma, 4 of whom had no tumor visible endoscopically. Five of the patients with cancer were among 25 patients (20 per cent) managed with an indwelling urethral catheter for more than 10 years (average 21 years, range 15 to 30 years). The other cancer patient had been free of the catheter for 27 years after suprapubic cystotomy for 4 years. Gross and microscopic hematuria was associated with cancer. Squamous metaplasia of the bladder was significantly greater in patients who had been catheterized for more than 10 years (80 per cent), compared to those catheterized for less than 10 years (42 per cent) and patients without catheters (20 per cent). Urethral squamous metaplasia increased slightly in long-term catheterization patients. Urinary infection was universal and did not distinguish patients with inflammation, metaplasia or cancer. Therefore, the duration of indwelling catheterization seems to be the major factor in squamous changes in these patients.

Adult↗
PubMed1976

Dissolution of residual renal calculi with hemiacidrin.

Hemiacidrin irrigation of the renal collection system via nephrostomy for the dissolution of residual postoperative calculi is described in 14 cases. The irrigation successfully dissolved 13 to 16 caliceal calculi. It did not dissolve any parenchymal calcifications. No known stones of pure calcium oxalate or apatite have been dissolved. Residual stones can safely be dissolved with hemiacidrin irrigation via nephrostomy if clear open drainage and scrupulously sterile urine are maintained.

Adult↗
PubMed1975

Live donor nephrectomy.

Donor nephrectomy was performed on 39 living related renal donors. The preoperative evaluation, surgical technique, and postoperative follow-up are presented. Major or minor complications developed in 23 per cent of the patients and included acute myocardial infarction, brachial plexus injury, acute glomerulonephritis, ileus, pneumonia, and urinary tract infection. All complications had resolved by six months postoperatively.

Adolescent↗
PubMed1975

Topical testosterone therapy for penile growth.

Three prepubertal males were treated with daily applications to the penis of 5 per cen topical testosterone cream. Penile growth occurred in all 3 patients. Serum testosterone values rose dramatically in 2 of the patients. Topical testosterone probably causes penile growth via its systemic action, not merely through its local effect.

Administration, Topical↗