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Biomedical subjects

G Jin

Publications and source records attributed to G Jin.

At least 73 records · Page 4Linked to original sources
PubMed1996

Resistance to retinoic acid and altered cytokeratin expression of human papillomavirus type 16-immortalized endocervical cells after tumorigenesis.

Human papillomaviruses (HPVs) and cigarette smoking are epidemiologically associated with cervical cancer. We recently found that HEN-16 and HEN-16-2 HPV type 16-immortalized endocervical cells form tumors after treatment with cigarette smoke condensate and derived 2 tumor cell line cultures, HEN-16T and HEN-16-2T, respectively. Here, we examine the molecular pathologic effect of tumorigenesis. HEN-16T and HEN-16-2T exhibit unchanged status and expression of integrated HPV 16 DNA. However, the expression of the cytokeratin CK7 and CK13 endocervical cell markers is more homogeneous in monolayer and organotypic raft cultures after tumorigenesis. For the effect of retinoic acid on monolayers for growth inhibition, HEN-16T were significantly less sensitive than the normal and immortalized non-tumorigenic cells. HEN-16-2T were completely resistant. Moreover, the rafts from both tumorigenic cell line cultures were resistant to retinoic acid and continued to display thick rafts and homogeneous severe dysplasia/carcinoma in situ. In contrast, the non-malignant HEN-16 and HEN-16-2 rafts were thinner, and treatment with retinoic acid blocked the formation of severe dysplasia, reconstructing an epithelium resembling that of the normal endocervix. Our results support the significance of non-viral factors in the mechanism by which cigarette smoking induces tumorigenesis in the late stages of HPV-initiated progression to cervical cancer. Importantly, our data indicate that the sensitivity to retinoic acid of the HPV-containing endocervical cells is lost following tumorigenesis in vitro and possibly in women.

Cell Division↗
PubMed1996

Transcriptional regulation of hydroxypyruvate reductase gene expression by cytokinin in etiolated pumpkin cotyledons.

To understand the mechanisms by which the expression of a specific gene is modulated by cytokinin, the regulation of hydroxypyruvate reductase (HPR) transcript levels by N6-benzyladenine (BA) in etiolated pumpkin (Cucurbita pepo L. cv. Halloween) cotyledons was investigated. A pumpkin HPR cDNA was generated by reverse transcriptase-polymerase chain reaction and its nucleotide sequence was determined. An antisense HPR RNA was prepared for RNase protection analysis of HPR-mRNA expression patterns in the cotyledons of dark-grown pumpkin seedlings. Treatment of the cotyledons with BA was shown to modulate HPR mRNA levels in a dose- and time-dependent manner. Similarly, nuclear run-on studies showed that the rate of transcription was also enhanced by BA treatment of the cotyledons. These results suggest that the enhancement of HPR mRNA by cytokinin is, at least in part, at the level of transcription.

Adenine↗
PubMed1996

Transabdominal esophagogastric devascularization as treatment for variceal hemorrhage.

BACKGROUND: During the past 18 years we have used a selective operative approach for variceal bleeders in whom endoscopic sclerotherapy failed or sclerotherapy was not indicated. Esophagogastric devascularization with splenectomy has been reserved for unshuntable patients and for those in whom a shunt was deemed inadvisable. The purposes of this study are to describe the surgical procedure technique and indications for esophagogastric devascularization and to report its long-term results. METHODS: Thirty-two patients who underwent either a limited (n = 9) or extensive (n = 23) esophagogastric devascularization procedure without esophageal transection for variceal bleeding were retrospectively reviewed. Common indications were thrombosis of all splanchnic veins (n = 12), distal splenorenal shunt thrombosis (n = 7), generalized portal hypertension with isolated splenic vein thrombosis (n = 5), and symptomatic splenomegaly or severe hypersplenism (n = 6). Eighteen patients (56%) had cirrhosis, eleven (34%) received an emergency operation, and eighteen (56%) bled from gastric varices. RESULTS: Three patients with Child's class C disease undergoing emergency surgery died during the early postoperative interval. Rebleeding occurred in nine surviving patients (31%) and was the cause of death in three. Rebleeding rates for the limited and extensive devascularization procedures were 50% and 24%, respectively. Only one of 11 patients with diffuse splanchnic venous thrombosis without liver disease has died. The 5-year survival rate of patients with liver disease was 51%. Only two patients experienced postoperative encephalopathy. CONCLUSIONS: When used in selected patients, esophagogastric devascularization without esophageal transection is a reasonably effective alternative to shunt surgery.

Adult↗
PubMed1996

Engraftment of chronic prolymphocytic and T cell leukemia in SCID mice.

Engraftment of human acute leukemia cells in immunocompromised (SCID) mice has resulted in in vivo models for exploration of human tumor biology. Attempts at engraftment of chronic leukemia cells have been generally unsuccessful. We have engrafted cells from three human chronic leukemias in SCID mice. Cell populations were from two patients with chronic lymphocytic leukemia (CLL) and either increased proolymphocytes (CLL-Pro; patient 1), or prolymphocytic transformation (PLL; patient 2) and from a third patient with newly diagnosed T cell CLL. Both fresh and cryopreserved cells were used and were injected intravenously, intraperitoneally, or both, after conditioning with cyclophosphamide. In addition, cells derived from a mouse spleen engrafted with human leukemia were passaged into another mouse. The animals were observed daily for signs of disease or appearance of tumors and sacrificed when terminally ill. At intervals blood samples were obtained and analyzed for the presence of human cells or DNA. Human leukemic cells were demonstrated by polymerase chain reaction (PCR) analysis of the human DQalpha gene or positive staining for human leukocyte common antigen (LCA). The presence of Epstein-Barr virus (EBV)-positive cells was also investigated by PCR analysis. Disseminated tumors developed in most mice inoculated with cells from the first patient, and this was associated with shortened survival times. The methods of administration, use of fresh or frozen samples, or the size of the inoculum had no effect on the development of leukemia. Survival of the mouse receiving passaged cells was similar to mice inoculated with fresh cells. Extensive histologic, immunophenotypic, and DNA studies were performed on organs from mice engrafting with cells from patient 1. PCR analysis for EBV sequences was negative in the mice engrafting from all three cases. The successful engraftment of human CLL-Pro PLL and T cell CLL in SCID mice, and the reproducibility of this effect using frozen cells, will provide a model for exploration of disease biology and for investigations of new drugs or combinations that may be useful in the treatment of CLL.

Aged↗
PubMed1996

[Microcolony observation for rapid detection and identification of cultures of Mycobacterium tuberculosis].

219 sputa were seeded on Kuang's agar plates. A total of 112 isolates of Mycobacterium tuberculosis were detected in 219 specimens. Of these 112 isolates, 104 (92.8%) were detected in Kuang's agar media and 108 (96.4%) were detected by microcolony observation. The detection time of microcolony observation and culture method needed 11 and 18.6 days respectively. The detection time of microcolony method is much shorter (P < 0.001). The results of conventional tests of different species of Mycobacterium and microcolony differentiation were identical in 99% of isolates of Mycobacterium tuberculosis.

Colony Count, Microbial↗
PubMed1995

A biosensor concept based on imaging ellipsometry for visualization of biomolecular interactions.

A new type of optical biosensor system is proposed and its application to detection of antigen-antibody complexes on a silicon substrate is demonstrated. The biosensor system is utilizing specificities of biomolecular interactions in combination with protein patterned surfaces. Visualization of the thickness distributions of thin layers (protein patterns) on a surface is achieved by using imaging ellipsometry. This technique uses a CCD camera whereby an ellipsometric analysis of a large surface can be made. The biosensor system has the advantages of high spatial resolution, fast data acquisition, and simplicity in use.

Adsorption↗
PubMed1995

Emergency shunt. Role in the present management of variceal bleeding.

OBJECTIVE: To evaluate the results of selective and nonselective emergency portosystemic shunts in patients with acute variceal hemorrhage. DESIGN: Retrospective review. SETTING: University medical center and Veterans Affairs medical center. PATIENTS: Forty-two consecutive patients who underwent emergency portosystemic shunts from 1978 through 1994. All patients had chronic liver disease (29 [69%] had alcoholic cirrhosis) and half had Child's class C disease. Sixteen patients were actively bleeding at the time of surgery, and 26 had bled within 48 hours. Twenty-two patients underwent a nonselective shunt and 20 underwent a distal splenorenal shunt. The percentages of patients with Child's class C disease and with active bleeding at the time of surgery were significantly higher in the nonselective shunt group. MAIN OUTCOME MEASURES: Operative mortality; early postoperative rebleeding, shunt patency, encephalopathy, and ascites; and long-term survival. RESULTS: Operative mortality rates were higher in patients with Child's class C disease (43% [9/21]) than in patients with Child's class A or B disease (9% [2/21]) and were higher in patients with active bleeding (all of whom underwent nonselective shunt) (44% [7/16]) than in patients who underwent distal splenorenal shunt (10% [2/20]). All shunts were patent after surgery, and no patient had rebleeding during the early postoperative interval. Early postoperative ascites and encephalopathy rates were similar after nonselective shunt and distal splenorenal shunt. Long-term survival was superior in the lower-risk distal splenorenal shunt group. CONCLUSIONS: Even though more effective nonoperative treatments are now available, emergency portosystemic shunt remains an important option for selected patients with acute variceal hemorrhage. When bleeding can be temporarily controlled by nonoperative means, distal splenorenal shunt is an effective and safe emergency procedure. The mortality rate remains high for patients with Child's class C disease undergoing protal decompression.

Emergencies↗
PubMed1995

Pancreatic complications after distal splenorenal shunt.

Pancreatic complications after the distal splenorenal shunt have not been commonly recognized. Between January 1978 and June 1993, 154 patients underwent a distal splenorenal shunt, and 11 patients (7%) developed pancreatic complications, of which 4 had pancreatitis alone, and 7 developed pancreatitis-related complications. Etiology of cirrhosis, Child's classification and timing of surgery were not predictive of pancreatic complications. Eight patients (5%) were found to have chronic pancreatitis at the time of surgery, and four of these patients (50%) developed pancreatic complications following distal splenorenal shunt. Eleven early postoperative deaths in our series resulted in an overall operative mortality rate of 7%. Of these eleven patients, 6 (55%) had postoperative pancreatic complications. The operative mortality rate of patients who developed pancreatic complications (55%) after distal splenorenal shunt was significantly greater than that of patients who did not develop pancreatic complications (3%), P < .001. When compared with patients without pancreatitis, those with pancreatitis had significantly greater incidences of complete or partial portal vein thrombosis (55% v 20%, P < .02), severe ascites (64% v 13%, P < .001), and encephalopathy (45% v 3%, P < .001). We reach the following conclusions: (1) although not a frequent complication after distal splenorenal shunt in general, pancreatitis was commonly present in early postoperative deaths and was most likely a major contributor to the demise of those patients; (2) survivors with postdistal splenorenal shunt pancreatitis had a markedly increased morbidity rate; and (3) pancreatic complications after distal splenorenal shunt are more likely to occur in patients with pre-existing chronic pancreatitis.

Abscess↗
PubMed1995

Glucagon, stress, and portal hypertension. Plasma glucagon levels and portal hypertension in relation to anesthesia and surgical stress.

Glucagon has been proposed as the mediator of splanchnic hyperemia in portal hypertension. Employing an assay specific for pancreatic glucagon, we reevaluated the relationship between this peptide and portal hypertension in the portal vein (PV)-stenosed rat model addressing, in particular, the effects of anesthesia and surgical stress. Plasma glucagon levels were similar in sham-operated and portal hypertensive rats: glucagon, sham vs PV stenosed: 110.7 +/- 17.1 pmol/liter vs 140.6 +/- 23.3 pmol/liter (NS). Furthermore, plasma levels of glucagon and the related peptide VIP were not significantly influenced by anesthesia or surgical stress, and levels remained similar under all conditions in sham-operated and PV-stenosed animals. We conclude that pancreatic glucagon is not elevated in the PV-stenosed rat; differences between these results and those describing hyperglucagonemia in this model cannot be explained on the basis of a differential response to stress but may reflect differences in glucagon assay system.

Anesthesia↗
PubMed1994

Comparative effects of intraduodenal psyllium and senna on canine small bowel motility.

BACKGROUND/AIM: To define the possible contribution of altered small intestinal motor activity to side-effects of bulking fibres, we sought to compare the relative effects of intraduodenal and intracolonic administration of the bulking fibre psyllium and the anthraquinone laxative senna on canine small intestinal motor activity. METHODS: Motor activity was recorded by serosal strain gauges implanted along the small intestine in 6 dogs. In random order, the motor responses to the instillation of psyllium (in doses of 5 or 10 g), senna (10 mg/kg) or appropriate vehicle (200 ml water infusion or saline 5 ml bolus) into either the proximal duodenum or proximal colon were assessed. RESULTS: The intra-duodenal administration of psyllium in either dose consistently induced a prolonged burst of 'clustered' contractions; in contrast, clusters were infrequent and of short duration following instillation of either vehicle or senna (P < 0.05). Intraduodenal instillation of psyllium inhibited migrating motor complex (MMC) migration and consistently delayed the onset of the next MMC cycle; a similar inhibition occurred with vehicle, however. Neither senna nor its vehicle inhibited MMC migration. None of these agents had any effect on small intestinal motor activity when instilled directly into the colon. CONCLUSIONS: Psyllium administered directly into the duodenum inhibits MMC activity and consistently induces 'clustered' contractions. Whilst the MMC-inhibitory effect appears to be a non-specific volume-related phenomenon, the induction of clusters is independent of volume or laxation. These motor effects of psyllium may contribute to the gastrointestinal symptomatology related to such agents and could be avoided by the preferential release of psyllium in the colon.

Animals↗
PubMed1993

Bacterial translocation in the portal-hypertensive rat: studies in basal conditions and on exposure to hemorrhagic shock.

BACKGROUND: Portal hypertension is associated with altered intestinal motor and mucosal function. The aim of this study was to determine whether portal hypertension, per se, or in association with acute hemorrhagic shock, predisposes to the translocation of bacteria across the intestine. METHODS: Translocation to both mesenteric lymph nodes and blood was compared in three groups of rats: portal-hypertensive (single-stage calibrated stenosis of portal vein), sham-operated, and unoperated controls. Half of the animals in each group were exposed to hemorrhagic shock. RESULTS: In the basal state, translocation to both mesenteric lymph nodes (portal hypertension vs. sham vs. controls, 411.5 +/- 119 vs. 151.1 +/- 42.6 vs. 18.1 +/- 12.6 colony-forming units [CFU]/g; P < 0.05) and blood (portal hypertension vs. sham vs. controls, 100% vs. 30% vs. 0% positive blood cultures; P < 0.05) was significantly increased in the portal-hypertensive animals. Furthermore, translocation was strikingly increased in these animals after hemorrhagic shock (mesenteric lymph node cultures, portal hypertension vs. portal hypertension with shock, 411 +/- 119 vs. 1018.2 +/- 372.2 CFU/g; P < 0.05). CONCLUSIONS: Portal hypertension promotes bacterial translocation, especially in relationship to acute hemorrhage. These findings may, in part, explain the susceptibility of patients with liver disease to sepsis of enteric origin.

Animals↗
PubMed1993

Shunt surgery versus endoscopic sclerotherapy for variceal hemorrhage: late results of a randomized trial.

Between September 1982 and April 1988, 60 cirrhotic patients with prior variceal hemorrhage were randomized to undergo the placement of an elective shunt (distal splenorenal: 26; nonselective: 4) or long-term endoscopic sclerotherapy (n = 30). Eighty-six percent of patients had alcoholic cirrhosis, and 33% were classified as Child's class C. After a mean follow-up of 87 months, 60% of patients undergoing sclerotherapy and 17% of shunt patients experienced rebleeding (p < 0.001). Shunt patients have survived longer than those who had sclerotherapy (6-year survival rates of 53% and 26%, respectively; p < 0.05). In part because of the wide geographic distribution of patients, only 4 of 13 patients in whom sclerotherapy failed (31%) could undergo salvage by shunt surgery. Although hepatic portal perfusion was better maintained after sclerotherapy, there were no major differences between the groups in terms of post-therapy hepatic or psychoneurologic function. In a predominantly alcoholic cirrhotic patient population (half non-urban), the results of elective shunt surgery were superior to those of chronic endoscopic sclerotherapy with respect to the prevention of recurrent variceal hemorrhage and survival.

Esophageal and Gastric Varices↗
PubMed1993

Variceal hemorrhage: surgical therapy.

Surgical options for management of variceal hemorrhage include portosystemic shunts (nonselective and selective), nonshunting operations, and hepatic transplantation. In most centers, operations that preserve hepatic portal perfusion (selective shunt and nonshunting operations) have replaced nonselective shunts as the most commonly performed surgical procedures. The results of multiple controlled trials suggest that the frequency of postshunt encephalopathy is less after the distal splenorenal shunt than after the nonselective shunts. Hepatic transplantation should be considered as initial therapy for nonalcoholic cirrhotics and abstinent alcoholic cirrhotics with variceal hemorrhage or advanced liver disease and without contraindications.

Algorithms↗