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Biomedical subjects

J K Stephens

Publications and source records attributed to J K Stephens.

At least 19 recordsLinked to original sources
PubMed1992

Application of the cavitron ultrasonic surgical aspirator (CUSA) for gynecological laparoscopic surgery using the rabbit as an animal model.

OBJECTIVE: To study the potential application of the cavitron ultrasonic surgical aspirator (CUSA) in gynecological laparoscopic surgery using a rabbit animal model. DESIGN: Twenty-six rabbits were prospectively randomized into two groups. Laparoscopically directed standard injuries were made on the randomly assigned horn and sidewall in all animals with the CUSA. Contralateral injuries were made with a contact neodymium-yttrium aluminum garnet (Nd:YAG) laser in group 1 and with bipolar cautery in group 2. Adhesion and inflammation scores were assessed for two animals in each group at 24, 48, and 72 hours, and seven animals in each group at 14 days. SETTING: University animal research facility. MAIN OUTCOME MEASURES: Adhesion and inflammation scores were compared between animals in the CUSA versus Nd:YAG study and the CUSA versus bipolar cautery at 14 days. RESULTS: No significant difference in uterine or sidewall adhesion scores was noted between the CUSA versus Nd:YAG or the CUSA versus bipolar cautery. Bipolar cautery produced significantly less inflammation on the uterine horn compared with the CUSA (3.0 +/- 0.2 versus 5.3 +/- 0.7, P = 0.0001), but no difference in sidewall inflammation was noted between the CUSA compared with bipolar cautery. No difference in inflammation was observed between the CUSA and the Nd:YAG laser. CONCLUSIONS: The bipolar cautery appears to be preferable to the CUSA for coagulation of uterine lesions, although dissection of the uterus is not possible with bipolar cautery. The CUSA and the Nd:YAG appear to be comparable for uterine horn dissection. Because the CUSA causes similar adhesion formation and tissue inflammation at the sidewall when compared with the Nd:YAG laser and bipolar cautery and may be less likely to damage blood vessels, ureters, or other collagen-rich tissues, the CUSA may represent a promising new surgical tool for laparoscopically directed peritoneal dissection.

Animals↗
PubMed1992

Evaluation of cryopreserved allograft venous conduits in dogs.

We investigated the effects of cryopreservation, immunosuppression, and antibiotic treatment on the patency and histologic appearance of venous conduits in the arterial circulation. Twenty-eight dogs received arterial replacements with autograft vein, fresh allograft, and two types of cryopreserved allograft vein implanted into both carotid and both femoral arteries. All animals were given aspirin, and half were given cyclosporine. After 3 months the vein grafts were harvested. Patency and light, transmission, and scanning electron microscopic criteria were scored to evaluate quality of preservation of the endothelium, the appearance of rejection, and the effects of cryopreservation with and without antibiotic pretreatment. The results show that patency is not statistically different based on graft type or treatment modality. The histologic appearance among the various vein types was remarkably similar at 3 months, with the exception of a cellular infiltrate present most prominently in the fresh allografts and least in the fresh autografts. Cyclosporine, even at a low dose, decreased the incidence of cellular infiltration. Preservation of endothelium was generally good in the cryopreserved allografts both with and without antibiotic pretreatment. In general, the effects of cryopreservation, cyclosporine, and antibiotics ameliorated the effects of venous allografting into an arterial position.

Animals↗
PubMed1991

Intestinal and hepatic apolipoprotein B gene expression in abetalipoproteinemia.

A 20-year-old woman with abetalipoproteinemia underwent orthotopic liver transplantation for cirrhosis, affording access to her liver and small intestine for study. Before transplantation, her plasma apolipoprotein B concentration was less than 1 mg/dL according to enzyme-linked immunosorbent assay, whereas after transplantation her plasma apolipoprotein B concentration was 76 mg/dL (all apolipoprotein B-100). Apolipoprotein B content was reduced in her intestine and liver compared with normal and cirrhotic controls. Cultured hepatocytes from the patient's explanted liver secreted a 1.006 g/mL less than or equal to d less than or equal to 1.063 g/mL lipoprotein rich in apolipoprotein E and a 1.063 g/mL less than or equal to d less than or equal to 1.21 g/mL lipoprotein containing apolipoproteins E and A-I with no immunodetectable apolipoprotein B in the culture medium. Normal hepatocytes secreted very low-density lipoprotein and low-density lipoprotein containing apolipoprotein B-100. Abetalipoproteinemic intestinal apolipoprotein B messenger RNA concentration was 4-5-fold higher than control values. However, the patient's liver apolipoprotein B messenger RNA level was one fifth that of control normal and cirrhotic liver. Analysis of the patient's intestinal and hepatic apolipoprotein B messenger RNA for posttranscriptional stop-codon insertion revealed normally edited transcripts. These results suggest that apolipoprotein B is synthesized as the product of a normally edited messenger RNA transcript, but not secreted, in abetalipoproteinemia.

Abetalipoproteinemia↗
PubMed1990

In situ distribution of the beta-subunit of platelet-derived growth factor receptor in nonneoplastic tissue and in soft tissue tumors.

The distribution of the beta-subunit of platelet-derived growth factor receptor (PDGFR-beta) was assessed by a sensitive immunoalkaline phosphatase technique using the monoclonal antibody PR7212. Frozen tissue sections of several nonneoplastic human tissues were stained along with 42 soft tissue sarcomas, 16 benign soft tissue proliferations, and 7 epithelial tumors. In all nonneoplastic tissue, there was intense labeling of cell processes of perivascular fibroblasts or pericytes in and about the walls of muscular blood vessels and of fibroblast cell processes around some glandular and ductal epithelia. No PDGFR-beta was found in the endothelial cells of muscular arteries and veins, but cells of uncertain identity within some capillaries were immunoreactive and the possibility that endothelial cells of some small capillaries express PDGFR-beta could not be excluded. In kidney there was strong labeling of glomerular mesangial cells and interstitial fibroblasts. Some histological types of soft tissue sarcomas were uniformly and strongly labeled with anti-PDGFR-beta, but other types were infrequently labeled or unreactive. The order of decreasing frequency and strength of labeling of the various types of benign and malignant soft tissue proliferations was as follows: benign fibromatosis and neurofibroma greater than malignant fibrous histiocytoma greater than liposarcoma greater than leiomyosarcoma greater than rhabdomyosarcoma. No tumor cell labeling was detected in epithelioid, synovial or clear cell sarcomas, leiomyomas, or carcinomas, but there was usually strong labeling of fibroblast and/or pericyte cell processes within tumor, especially around blood vessels. We conclude that PDGFR-beta is strongly expressed by vascular and stromal tissues of most tumors and normal organs and by tumor cells of several types of soft tissue tumors and proliferations, most notably those of fibroblastic origin.

Blood Vessels↗
PubMed1990

Flow cytometric DNA analysis of squamous cell carcinoma of the esophagus.

Although an abnormal amount of cellular DNA content is known to occur in squamous cell carcinoma of the esophagus, the significance and clinical relevance of this finding have yet to be elucidated. Paraffin-embedded blocks from 77 patients with squamous cell carcinoma of the esophagus were dewaxed and made into a suspension by mechanical mincing and enzymatic digestion. The nuclei were stained with propidium iodide, and the DNA content evaluated with flow cytometric study. The DNA index (DI) and the coefficient of variation were determined and the results were compared with other pathologic prognostic features. DNA aneuploidy was identified in 70.1% of the specimens and found to correlate significantly with both histologic grading (P less than 0.025) and the incidence of postoperative recurrence (P less than 0.05). Although the 5-year survival was slightly better in the euploid group than in the aneuploid group (28.8% and 19.1%, respectively), this difference was not statistically significant (P greater than 0.1). There was no correlation of the DI with the extent of wall penetration by the tumor, the incidence of lymph node metastases, or the surgical staging, features previously shown to correlate with prognosis in patients with esophageal carcinoma.

Carcinoma, Squamous Cell↗
PubMed1990

Expression of ras oncogene p21 protein in esophageal squamous cell carcinoma.

In order to investigate the value of ras oncogene expression as a prognostic indicator in esophageal squamous cell carcinoma, we evaluated the level of ras oncogene protein product (p21) in 52 specimens resected between 1977 and 1986. All patients were followed until death or for at least 2 years. Pathology slides and archival paraffin blocks were retrieved for confirmation of the original diagnosis, study of histopathologic features, and measurement of p21 content. P21 titers were obtained using the RAP-5 monoclonal antibody in a semiquantitative immunohistochemical assay. Titer was expressed as the highest dilution of antibody giving definitive staining using the avidin-biotin peroxidase method. Ras oncogene was expressed in 88.5% of the specimens. We did not find a significant correlation between ras expression and any of a variety of clinical and histopathologic prognostic parameters. Although patients' median survival after resection of specimens with ras oncogene expression was less than half the median survival after removal of tumors without such expression, this difference was not statistically significant. Further prospective investigations are needed to assess the role of ras oncogene evaluation in clinical practice.

Adult↗
PubMed1990

Indications for esophagectomy in nonmalignant Barrett's esophagus: a 10-year experience.

Between 1978 and 1988, 88 patients were referred for the surgical treatment of nonmalignant Barrett's esophagus. Nineteen patients required esophageal resection. Male/female ratio was 13:6; age range was 13 to 84 years (mean age, 49.8 years; median age, 40 years). Preoperative studies demonstrated strictures in 11 patients and ulcers in 7. Penetrating Barrett's ulcer resistant to treatment was the indication for resection in 5 patients. Ulcers penetrated to the pericardium (1 patient), pulmonary vein (1), lung (1), and mediastinum (2). Other indications for resection included undilatable strictures (2), previous operations (4), high-grade dysplasia (3), parietal cells lining the esophagus (1), patient's refusal of long-term surveillance (2), and the inability to exclude adenocarcinoma preoperatively (2). Reconstruction was achieved by colon interposition (15) or esophagogastrostomy (4), with one postoperative death. Mean follow-up was 41 months and was 100% complete. Of the 18 patients, 3 have occasional regurgitation but none have any dysphagia or weight loss. Esophageal resection is indicated in a select group of patients with Barrett's esophagus. Absolute indications include a deep penetrating ulcer confirmed intraoperatively, high-grade dysplasia, strong suspicion of cancer, and multiple previous operations. Relative indications include strictures not responding to dilation and young patients refusing long-term surveillance.

Adolescent↗
PubMed1990

Morphology in Ki-1(CD30)-positive non-Hodgkin's lymphoma is correlated with clinical features and the presence of a unique chromosomal abnormality, t(2;5)(p23;q35).

Ten patients with strongly Ki-1(CD30)-positive non-Hodgkin's lymphoma (NHL) were identified at our institution during the past 5 years. Based on morphology, the lymphomas of five of these patients were classified as anaplastic large-cell lymphoma (ALCL); the lymphomas of four patients lacked the morphologic features of ALCL (non-ALCL); and the lymphoma of one patient was unclassifiable. Significant clinical and cytogenetic differences were observed between patients with ALCL and those with non-ALCL. The patients with ALCL tended to be young at the time of diagnosis. They presented with peripheral lymphadenopathy, and two of the five patients had skin involvement. An identical reciprocal translocation involving chromosomes 2 and 5 [t(2;5)(p23;q35)] was observed in lymph nodes from each of the two ALCL patients whose chromosomes were studied. Four of the five patients with ALCL are alive and in complete remission 10-27 months after receiving systemic chemotherapy. In contrast, the patients with non-ALCL were heterogeneous with respect to clinical findings. All of the non-ALCLs were histologically aggressive; however, their morphology varied. The t(2;5) was absent in the lymphoma specimens from each of three non-ALCL patients studied. Three of the four patients died within 17 months after receiving systemic chemotherapy. Thus, differences in morphology are correlated with differences in the clinical findings, karyotype, and outcome in Ki-1-positive NHL.

Antigens, CD↗
PubMed1990

Endoscopic and histologic findings in the upper gastrointestinal tract of children with Crohn's disease.

In an attempt to define endoscopic and histologic changes suggestive of upper gastrointestinal Crohn's disease (CD), the medical histories, endoscopic reports, and biopsies were reviewed from 24 pediatric patients with CD and 28 age-matched patients without CD in whom esophagogastroduodenoscopies were performed because of upper GI symptoms. No differences in the overall frequency of endoscopic abnormalities were found between the two groups. However, gastric erosions and ulcerations were more frequent in CD patients. Histological abnormalities in the stomach and duodenum were also more frequent in CD patients. Noncaseating granulomas were found in five patients with CD and in one patient without clinical, radiologic, or endoscopic evidence of CD. Focal inflammation in the stomach and duodenum occurred more frequently in CD patients. Two patients with CD had focal and deep chronic inflammatory infiltrates in the esophagus, which reached the submucosa. Abnormal histology was often seen in CD patients with normal endoscopic appearances. We conclude that superficial ulcerations seen during endoscopy and the histological finding of focal inflammation may represent upper GI CD in pediatric patients. Histological changes can be missed if biopsies are not taken from normal-appearing mucosa during endoscopy.

Adolescent↗
PubMed1989

Correlation between automated karyometric measurements of squamous cell carcinoma of the esophagus and histopathologic and clinical features.

The clinical staging of esophageal carcinoma is unreliable currently, making it difficult to select patients for aggressive therapy. To further refine staging criteria, the nuclear characteristics of a series of 31 patients with squamous cell carcinoma of the esophagus were studied using a computerized image analysis system (MicroTICAS). Karyometric measurements, including total nuclear DNA content, nuclear area, and nuclear roundness were compared with various clinical and histologic variables. Nearly all tumors (30 of 31) were aneuploid. Tumors with nuclear areas greater than 70 microns2 were associated with transmural esophageal penetration (P less than 0.05) and to a lesser extent with poor survival (less than 6 months; P = 0.06). Surprisingly, nuclear ploidy did not correlate with either variable. These data support a role for nuclear analysis on preoperative biopsy specimens as an adjunct in clinical staging.

Aneuploidy↗
PubMed1989

Unusual urethral diverticulum lined by colonic epithelium with Paneth cell metaplasia.

Diverticulum of the female urethra has an incidence of 1.4% to 4.7%. It is generally agreed that the majority of these are acquired lesions. There is, however, evidence that some are of congenital origin. Documented cases of diverticula with colon-type tissue are rare. A case of urethral diverticulum with colonic epithelium and features of Paneth cell metaplasia is presented. Causes, symptoms, diagnostic methods, and treatment are discussed.

Adult↗
PubMed1989

A case report of three synchronous stage I malignant neoplasms.

A patient with three synchronous, Stage I neoplasms of the ovary, kidney, and lung, who underwent resection of all lesions at the same operative procedure, is presented. The incidence of multiple primary malignancies and the prognosis for Stage I cancers of the ovary, kidney, and lung are reviewed.

Adenocarcinoma↗
PubMed1988

Barrett's ulcer.

A case of an ulcer developing within previously documented Barrett's epithelium is reported. The patient had symptoms of gastroesophageal reflux for many years and Barrett's esophagus beginning 21 cm from the incisor teeth was documented by endoscopy one year earlier. Hospitalization was necessitated by an upper gastrointestinal bleed which was found to be due to an ulcer at 29 cm from the incisors. There was no inflammation of the surrounding columnar epithelium nor was there any esophagitis within the squamous epithelium. This case documents that ulcers in Barrett's esophagus can arise de novo within the columnar epithelium despite the hypothesis that this epithelium is present because it is more resistant to acid/peptic damage than squamous epithelium. This suggests that some ulcers in Barrett's epithelium may be due to spontaneous degeneration of the epithelium as this patient had no esophagitis, suggesting that gastroesophageal reflux was not causing diffuse damage.

Aged↗
PubMed1979

Hormonal effects on the regulation of hepatic heme biosynthesis.

Drug-induced porphyrin accumulation occurs in chick embryo liver cells maintained in serum-free Waymouth MD 705/1 medium. Addition of insulin and thyroxine to the medium results in a marked enhancement of porphyrin accumulation. The addition of hydrocortisone results in a further enhancement of porphyrine accumulation. Several agents which are reported to increase intracellular adenosine 3':5'-monophosphate (cAMP) levels, viz. glucagon, sodium fluoride, cAMP or its dibutyryl derivative, 3-isobutyl-1-methylxanthine and papaverine enhanced drug-induced porphyrin biosynthesis. On the other have, agents which are reported to decrease intra-cellular cAMP levels, viz. alloxan and imidazole, diminished drug-induced porphyrin accumulation. cAMP appears to enhance, but not to function as a "second messenger" in drug-induced porphyrin biosynthesis. Drug-induced porphyrin accumulation in chick embryo liver cells depend upon the insulin to glucagon ratio. A low level of porphyrin accumulation occurs at insulin to glucagon ratios similar to those found following glucose administration in vivo, suggesting a possible explanation for the therapeutic effect of glucose in hepatic porphyria. The 5 alpha A(A:B trans) and 5 beta H(A:Bcis) steroids are equipotent in inducing delta-aminolevulinic acid synthetase and porphyrin accumulation in chick embryo liver cells maintained in serum-free culture medium. Thus, there is no specific steric requirement for porphyrin-inducing activity in steroids.

1-Methyl-3-isobutylxanthine↗