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Biomedical subjects

S M Lin

Publications and source records attributed to S M Lin.

At least 73 records · Page 4Linked to original sources
PubMed1994

Oncogenic Ras blocks cell cycle progression and inhibits p34cdc2 kinase in activated Xenopus egg extracts.

The effect of purified, bacterially expressed human RasH proteins on embryonic cell cycle progression in activated Xenopus egg extracts was studied. Bacterially expressed human oncogenic RasH protein is able to block the progression of the Xenopus embryonic cell cycle into M-phase. In contrast, the corresponding normal human Ras protein is relatively ineffective when assayed in a like manner. The observed arresting activity can be blocked by the addition of Y13-259 anti-Ras monoclonal antibody but not by nonspecific IgG. Oncogenic Ras also induces unique morphological changes in the reconstituted nuclei; the nuclei appear to be enlarged, and the chromatin partially condenses into fiber-like structures. This induced arrest is associated with suppression of p34cdc2 kinase activity, indicating that the oncogenic Ras protein induces the arrest by inactivating p34cdc2. This inactivation by oncogenic Ras protein does not result from inhibition of the synthesis of cyclin B or of the binding of the newly synthesized cyclin B to the p34cdc2.

Animals↗
PubMed1994

Intraoperative transcranial electrical motor evoked potential monitoring during spinal surgery under intravenous ketamine or etomidate anaesthesia.

Motor evoked potentials (MEPs), monitoring the motor function directly, are superior to somatosensory evoked potentials (SSEPs) in monitoring the motor system during spinal surgery. Reliable MEPs are difficult to elicit under normal anaesthesia. Using intravenous anaesthesia with either ketamine or etomidate infusion, we performed intraoperative MEP monitoring in 12 spinal operations for 11 cases from February 1992 to May 1992. For anaesthesia, ketamine was used in 5, etomidate in 7, fentanyl was supplemented in all, muscle relaxation at 30% to 50% of pre-anaesthetic muscle power was maintained with atracurium or vencuronium infusion. Transcranial bipolar electrical stimulation was used to induce MEPs. Concomitant SSEP monitoring was performed in 3. No significant anaesthesia related side effects were noted except one episode of unpleasant dream occurred in the ketamine anaesthesia group. Successful monitoring was achieved in 10 sessions. In 5 of which warning to the surgeons was made due to sudden MEP deterioration, which recovered followed by definite management in four and persisted in one. In the other 5 sessions, no warning was made due to stationary or gradual change in MEPs. Bilateral two-channel recordings were used in 3 sessions. In 2 of which unilateral transient change was noted. Loss of SSEPs was noted in one despite unchanged MEPs, in whom only new sensory deficits occurred postoperatively. Compared to the baseline MEPs in terms of latency and amplitude, the final MEPs improved in 5 sessions, did not change significantly in 4 sessions, deteriorated in one session, and were correlated well with the immediate postoperative motor status.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Beneficial effect of prednisolone withdrawal followed by human lymphoblastoid interferon on the treatment of chronic type B hepatitis in Asians: a randomized controlled trial.

To evaluate the effect of interferon and the benefit of prednisolone pretreatment in Oriental patients with chronic active hepatitis B, 120 male Chinese patients were randomly allocated to receive: 1) group A: a 4-week course of prednisolone followed by 2 weeks of no treatment and then a 12-week course of human lymphoblastoid interferon, 4 to 6 MU/m2 intramuscularly; 2) group B: as group A, but with placebo given instead of prednisolone; 3) group C: an 18-week course of placebo. Clearance of serum hepatitis B virus-DNA and HBeAg (complete response) was achieved in 21% of group A, 5% of group B and none of group C at the end of therapy (A vs B: p = 0.054; A vs C: p < 0.01). When assessed 12 months after the end of therapy, the complete response rate was 46% in group A, 24% in group B and 25% in group C (p < 0.05). Those with baseline alanine transaminase < or = 200 U/l showed a better response to interferon following prednisolone withdrawal (48%) than with interferon therapy alone (20%, p = 0.056) and no treatment (9%, p < 0.01). Those with a baseline serum hepatitis B virus-DNA < or = 1000 pg/ml also showed a higher complete response rate when pretreated with prednisolone (59%) than when treated with interferon alone (29%, p = 0.084) or untreated (22%, p < 0.03). The strongest independent predictor of a response to treatment was prednisolone withdrawal (p < 0.05). None of the responders lost hepatitis B surface antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Cholangiography of icteric type hepatoma.

OBJECTIVES: Icteric type hepatoma caused by floating tumor debris in the major bile duct was rare. Such cases were often incorrectly identified as biliary carcinoma or choledocholithiasis until pathological proof. The goal of this study was to analyze the cholangiograms of icteric type hepatomas, and to identify the characteristic cholangiographic features of this rare disease. METHODS: A retrospective analysis of 20 cholangiographies of icteric type hepatomas during a 10-yr period was carried out. RESULTS: There were 15 males and five females in this series. Seventeen (85%) patients were hepatitis B virus carriers, and liver cirrhosis was detected in 16 (80%) patients. Serum alpha-fetoprotein levels in 13 (65%) of the patients were over 400 ng/ml. The cholangiographic findings included: 1) intraductal filling defects resulting in partial or complete obstruction and ductal dilation in 14 cases (70%), 2) abrupt complete obstruction of the common hepatic duct with an irregular cut surface in three cases (15%), and 3) tumor encasement and stricture of the biliary system in three cases (15%). Management of these patients included hepatic resection, choledochotomies with T tube stenting, or PTCD. Most of them died within one-half year after diagnosis, but one patient in our series, who received hepatic resection, survived more than 70 months. CONCLUSIONS: It is important to recognize this group of patients. Because with proper management, good palliation or cure is possible. The cholangiographic appearances, when taken alone, are not diagnostic of icteric type hepatomas. Once these cholangiograms are seen in patients with associated risks of developing a hepatoma, such as liver cirrhosis, chronic viral hepatitis, and elevated serum alpha-fetoprotein, however, an icteric type hepatoma should be suspected.

Adult↗
PubMed1994

Percutaneous lumbar discectomy: indications and surgical results in 35 consecutive cases.

Thirty-five patients (27 men and eight women) who met our criteria of case selection for percutaneous lumbar discectomy (PLD) were treated by this method during the period May 1992 to June 1993. Thirty-six spaces, including one man with double disc disease, were decompressed. Patients ranged in age from 14 to 64 years. All patients but one were followed up for a minimum of six months. The operative results, evaluated by a more objective functional grading system, revealed a short-term (two months) success rate of 83% and a mid-term (six months) success rate of 76%. This discrepancy resulted from two recurrences of sciatic symptoms. It indicates that the medical conditions of those who have received PLD are by no means static, but instead may fluctuate. The operative result was similar to that of open discectomy, averaging 81.1% in reported series. Our "functional grading system" reflects these fluctuations quantitatively. With respect to the operative success rate, there was a statistical difference between the very good, good and fair-poor indication groups of patients, as were categorized by our major criteria of indications that included three clinical manifestation criteria and the other three radiographic findings. This result emphasizes the critical role of case selection in the operative success rate. Complications consisted of one disc infection which cleared without sequelae. This study provides an objective means of selecting cases and evaluating surgical results which, in turn, makes the use of this procedure convincing and predictable.

Adolescent↗
PubMed1994

Sexual precocity due to intracranial human chorionic gonadotropin-secreting tumor: report of a case.

Human chorionic gonadotropin (HCG)-secreting tumors are one of the causes of isosexual precocity in boys. A seven-year-old boy had been noted to have an increased appetite, accelerated growth and the development of pubic hair in the previous three months. He had an elevated serum testosterone level (16.79 ng/mL). However, the response of luteinizing-hormone and follicle-stimulating-hormone to gonadotropin releasing hormone stimulation was suppressed. An intracranial tumor at the left thalamus was disclosed by a magnetic resonance image scan of the head, and an elevated HCG level (120 mIU/mL) was also noted. Sexual precocity due to an intracranial HCG-secreting tumor was diagnosed and a partial resection of the tumor followed by radiotherapy was carried out. His serum testosterone and HCG levels became undetectable, and the secondary sexual characteristics regressed after treatment.

Brain Neoplasms↗
PubMed1993

Ultrasonographic changes of early liver cirrhosis in chronic hepatitis B: a longitudinal study.

Ultrasonography of prospectively followed chronic hepatitis B patients who developed liver cirrhosis were reevaluated in order to identify the ultrasonographic changes of early cirrhosis. Ultrasonographic features of 29 patients before and after cirrhosis were as follows: portal vein diameter--1.20 cm/1.29 cm (NS); cirrhosis score--5.69/7.52 (p < 0.01); spleen size index--21.99 cm2/25.84 cm2 (NS). The result suggests that ultrasonographic diagnosis of early cirrhosis is not easy on a single occasion; however, the score system method is helpful in longitudinal follow-up chronic hepatitis patients. A careful comparison of hepatic parenchymal and surface changes are mandatory.

Chronic Disease↗
PubMed1993

Sex difference in chronic hepatitis B virus infection: studies of serum HBeAg and alanine aminotransferase levels in 10,431 asymptomatic Chinese HBsAg carriers.

To study the difference between the sexes with regard to chronic hepatitis B virus infection, we surveyed levels of serum hepatitis B e antigen (HBeAg) and alanine aminotransferase (ALT) among 10,431 asymptomatic Chinese carriers of hepatitis B surface antigen (HBsAg) in Taiwan. There were 7,095 men and 3,336 women in this study; ages ranged from 15 to 70 years. HBeAg was detected in 19.6% of HBsAg carriers. The prevalence of HBeAg decreased significantly with increasing age. HBeAg was detected in 17.7% of men and 23.6% of women. After correction for the confounding effect of age, it was found that the prevalence of HBeAg was significantly higher among women than among men. The level of serum ALT was abnormal in 20.8% of HBsAg carriers. Abnormal ALT levels were significantly more frequent among HBsAg carriers who tested positive for HBeAg (39.7%) than among those who did not (16.2%; P < .001). Among the HBeAg-positive carriers, 43.2% of men and 34.2% of women had abnormal ALT levels, and men were 1.45 times more likely to have abnormal ALT levels than women (P < .001). Among the carriers who were negative for HBeAg, 20.6% of men and only 6.0% of women had abnormal ALT levels, and men were 3.98 times more likely to have abnormal ALT levels than women (P < .001). Overall, 24.6% of men and only 12.6% of women had abnormal ALT levels, and men were 2.33 times more likely to have abnormal ALT levels than were women (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

The incidence of bladder cancer in the black foot disease endemic area in Taiwan.

A high incidence of bladder cancer (23.53/100,000 population per annum from 1981-1985) was found in an endemic area of peripheral vascular disease known as black foot disease (BFD) on the southwest coast of Taiwan. The average incidence of bladder cancer in the whole of the Taiwan area was 2.29/100,000 during the same period. The incidence of female bladder cancer (21.10/100,000) in this area was also high. The ratio of male to female bladder cancer in the BFD endemic area and the neighbouring area was 1.24 and 1.09, lower than that in the whole Taiwan area (2.75) and elsewhere around the world. The high content of arsenic and the high concentration of a "fluorescent substance" in artesian well water in this area are the only 2 related factors identified so far. Determination of the actual carcinogen requires further investigation.

Female↗
PubMed1993

Effects of prednisolone pretreatment in interferon alfa therapy for patients with chronic non-A, non-B (C) hepatitis.

The effect of corticosteroid pretreatment on interferon alfa treatment of chronic non-A, non-B or C hepatitis was evaluated in an open, randomized, controlled study. Normalization of the serum alanine aminotransferase level, which suggested complete response, was recorded in 14 (56%) of 25 patients at the end of a 6-month treatment with 3 million units of interferon alfa three times weekly alone. Prednisolone withdrawal followed by the same interferon alfa treatment resulted in complete response in 14 (61%) of another 23 patients. Both of these rates are significantly higher than the spontaneous ALT normalization rate of 9% observed in 2 of 22 patients during the same period (p < 0.01). ALT normalized within 2 months of interferon therapy in most (89%) of the complete responders. Of the patients pretreated with prednisolone, 43% showed a "rebound" following prednisolone withdrawal and 89% of the patients with "rebound" responded to subsequent interferon therapy. The cumulative probability of sustained remission in patients with and without prednisolone pretreatment in a 24-month period of follow-up after the end of therapy was 79% and 30%, respectively (p < 0.05). Clinical relapse mostly (85%) occurred within 3 months after the end of therapy. No obvious factor could be identified as a predictor of response or relapse. The results of this study suggest that prednisolone withdrawal tends to enhance the durability of the beneficial effects of interferon alfa therapy in patients with chronic non-A, non-B or C hepatitis.

Alanine Transaminase↗
PubMed1993

[The effects of ketamine, propofol and nitrous oxide on visual evoked potential during fentanyl anesthesia].

To evaluate the effects of ketamine, N2O, propofol on visual evoked potential (VEP) during fentanyl anesthesia, 14 patients undergoing transphenoid pituitary dissections were studied. Visual stimulation was done by using the goggles with red light diodes through closed eyelids and responses were recorded in one channel montage, Cz against Oz. The stimulus frequency was 1.9 flashes/sec. The VEPs were recorded from skin incision until the opening of the dura. For comparison, the preanesthesia to anesthesia values were determined. The ratio for N2 (N75) latency were 100.5 +/- 13.9% in ketamine group, 104 +/- 3.5% in N2O group, 100.5 +/- 4.2% in propofol group. The ratios for P2 (P100) latency were 97.45 +/- 5.7% in ketamine group, 101.9 +/- 3.5% in N2O group, 96.8 +/- 5.5% in propofol group. For N2P2 amplitude, the ratios were 36.3% +/- 31.4% in ketamine group, 138.5 +/- 58.0% in N2O group, 80.8 +/- 42.2% in propofol group. The percentage of inadequate recordings were 2.5 +/- 4.3% in ketamine group, 19.2 +/- 2.2% in N2O group and 20.6 +/- 16.0% in propofol group. The percentage of false positive results were 0 +/- 0% in ketamine group, 9.8 +/- 19.9% in N2O group, 12.7 +/- 13.2% in propofol group. Satisfactory anesthesia was achieved in all groups except for ketamine group which required additional medications for elevated blood pressure and intracranial pressure, and postoperative nausea and vomiting. It is concluded that there was great variability of VEP during anesthesia and surgery. Amplitude rather than latency changes were observed during anesthesia combined with fentanyl.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Therapy for supratentorial malignant astrocytomas: survival and possible prognostic factors.

Maximum feasible resection of the tumor followed by 50 Gy whole brain irradiation was the routine management for patients with malignant glioma in this series. To determine treatment results and possible prognostic factors, a retrospective analysis was done of 116 patients with pathologically proven supratentorial malignant astrocytomas (71 glioblastoma multiforme and 45 anaplastic astrocytoma) from January 1981 to December 1990. The mean age of the patients at the time of diagnosis was 46 years for glioblastoma multiforme and 37 years for anaplastic astrocytoma. In 86% of the patients, their condition improved or was constant after surgery; in 14% of the patients, the conditions worsened. The median survival time was 10 months for patients with glioblastoma multiforme and 22 months for those with anaplastic astrocytoma. Cox regression analysis showed that the duration of symptoms, extent of resection, irradiation and tumor histology were significantly related to the survival time. However, gross total resection did not improve the survival time relative to a subtotal resection, although both were shown to be better than a partial resection or biopsy.

Adult↗
PubMed1993

Prognostic factors of intraspinal neurilemmoma and meningioma with severe preoperative motor deficits.

A total of 20 cases of intraspinal benign tumors (13 neurilemmomas and seven meningiomas) with severe motor deficits operated on from 1978 to 1991 were reviewed. Motor deficits were graded according to the classification of Cooper and Ebstein. Grade IV represented slight movement of the lower extremities, but no ability to walk or stand; grade V was complete paralysis. There were 16 patients classified as grade IV and four classified as grade V. All patients underwent total excision of the tumor and postoperative physical therapy. After various periods of follow-up, 13 patients could walk independently, five could walk with assistance, one could stand, and one was still restricted to a wheelchair. For the 13 patients who could walk independently, 11 were able to stand within one month after surgery. In contrast, of the seven patients who could not walk independently, only two managed to stand within one month of surgery. Statistically, age, duration of paraplegia and tumor location all had a significant influence on the recovery of motor function. Being able to stand within one month of surgery was predictive of a good recovery.

Adult↗
PubMed1993

Acute viral hepatitis in the elderly.

Seventy-six cases of acute viral hepatitis in the elderly (65 years old or older) were reviewed. Their clinical symptoms, biochemical pictures and clinical courses were compared with patients less than 40 years old (young) and those 40-64 years old (middle-aged). There were 51 men and 25 women with the mean age of 69 years (range 65 to 78 years). The most common etiology of acute viral hepatitis in the elderly is acute non-A, non-B hepatitis (48.7%), followed by acute hepatitis in HBsAg carrier (44.7%) and acute type B hepatitis (7.9%). Acute hepatitis in HBsAg carrier is the most common etiology in the young and middle-aged patients. Gastric flu, deep or tea colored urine and fatigue-weakness are the common clinical presentations. In conventional liver function tests, serum levels of GPT and albumin tended to be lower in the elderly patients. Overall, 25% of acute viral hepatitis in the elderly were complicated with fulminant hepatic failure or subacute hepatic failure and 18.4% died. The prevalence of fulminant or subacute hepatic failure and the mortality in the elderly were significantly higher than those in the younger patients.

Acute Disease↗
PubMed1992

Effects of anticoagulants and storage of blood samples on efficacy of the polymerase chain reaction assay for hepatitis C virus.

Blood samples from 11 patients with posttransfusion hepatitis C virus infection were collected. Each sample was divided into three fractions to obtain sera, sodium-citrated plasma, and heparinized plasma and then tested for HCV RNA by a nested polymerase chain reaction (PCR). Of them, eight sodium-citrated plasma samples, seven serum samples, and no heparinized plasma samples were PCR positive. Eight PCR-positive sodium-citrated plasma samples were exposed to different physical conditions and semiquantified for HCV RNA after serial dilutions. Samples stored at -70 degrees C showed the best preservation of HCV RNA, and storage at the other conditions resulted in only minimal loss of the PCR signal. Therefore, serum or sodium-citrated plasma specimens are satisfactory for detecting HCV RNA by PCR, but heparinized blood specimens are not.

Anticoagulants↗