Biomedical subjects

T J Chen

Publications and source records attributed to T J Chen.

At least 91 records · Page 5Linked to original sources

PubMed1992

Assay of fluconazole by high-performance liquid chromatography with a mixed-phase column.

A mixed-phase liquid chromatographic column was used to assay fluconazole in plasma, serum, and cerebrospinal fluid. The assay was linear from 0.2 to 20 micrograms/ml, with an average coefficient of variation of less than 5%. The partitioning of the drug between serum and cerebrospinal fluid was determined for 34 patients. The method was demonstrated to be suitable for both pharmacokinetic studies and monitoring of patients receiving treatment with this antifungal agent.

Chromatography, High Pressure Liquid↗

PubMed1992

[Brainstem auditory evoked potentials in diabetes mellitus].

It is well-known that diabetic patients develop peripheral and autonomic neuropathy, and recent review has also suggested the occurrence of central pathway abnormality in diabetics. In this article, we conducted the BAEP study on 61 cases of NIDDM and 11 cases of IDDM. Peak latency, interpeak latency (IPL) and peak amplitude of BAEPs were analyzed in each case. For further correlation, the motor and sensory nerve conduction velocities of median nerve, the blood sugar, the serum HbA1c were measured. Two nondiabetic groups, age and sex matched with NIDDM and IDDM groups, were used as control. In NIDDM group, the results showed prolongation of all peak latency and IPL except peak latency of wave II and wave IV in the left side and bilateral IPL III-V. There was no statistically significant amplitude difference between NIDDM and age-matched control group. The result of IDDM group revealed prolongation of all peak latency and IPL, except the right IPL III-V. As for amplitude, waves III and V in the right side and waves I and V in the left side were reduced as compared with the age-matched young control group. There was no statistically significant difference in all peak latencies and IPLs between NIDDM and IDDM groups. In both groups of NIDDM and IDDM, the MNCV and SNCV of median nerve were significantly delayed in conduction. The prolongation of III and V peak latency had a linear correlation with their amplitude reduction. In conclusion, both peripheral and central conduction dysfunction occur in both IDDM and NIDDM patients.

Adult↗

PubMed1992

Spontaneous regression of hepatocellular carcinoma.

We report a 65-yr-old man with hepatitis B virus-related liver cirrhosis and biopsy-proven hepatocellular carcinoma who has undergone spontaneous regression. The tumor became impalpable, and was no longer detectable by ultrasonography and computed axial tomography, 5 and 30 months later. The alpha-fetoprotein level also decreased to normal range. The clinical course is silent, and the patient is alive and well 37 months after the initial diagnosis.

Aged↗

PubMed1992

[A clinicopathological study in primary biliary cirrhosis].

Twenty-two patients with clinical, biochemical, immunological and pathological characteristics compatible with primary biliary cirrhosis were studied. There were 17 women and 5 men with a mean age of 57.4 +/- 15.2 years and a mean follow-up of 24.1 +/- 20.1 months. Four of them expired during the follow-up and eighteen patients now survive. The most common complaints were fatigue (63.6%) and itching (59.1%). Only one case (4.5%) was asymptomatic in this series. The major physical findings were jaundice (50%) and hepatomegaly (50%). The significant laboratory findings were: elevation of alkaline phosphatase (91% of the cases greater than 3 times the upper limit of normal), gamma-glutamyl transpeptidase (100% of the cases greater than 4 times the upper limit of normal), aspartate transaminase (95%) and alanine transaminase (100%), presence of anti-mitochondrial antibodies (91%), antinuclear antibodies (73%) and the elevation of IgM (88%). One case was associated with ulcerative colitis. Pathological staging in this series revealed 57.9% of stage II, 26% of stage III, 10% of stage IV and 5.3% of stage I. All patients with granuloma survived but 4 of the 5 patients with cholestasis died during follow-up. The results show that the features in this series of PBC were similar to those observed in western countries. The very high ALP and gamma-GT level as well as only one asymptomatic case in this series, suggest that our patients were diagnosed at a late stage. The reason(s) for the higher positivity of ANA, particularly the speckled type and a lower rate of associated auto-immune disease requires further study. Liver biopsy in predicting a prognosis is valuable.

Adult↗

PubMed1992

Effects of aircraft noise on hearing and auditory pathway function of airport employees.

The effects of aircraft noise on hearing and auditory pathway function were studied in 112 airport employees, both by audiometry and brainstem auditory evoked potentials (BAEPs) to evaluate cochlear function and to verify the possibility of retrocochlear involvement. Employees were divided into five groups according to their daily jobs. Group A was made up of 23 maintenance workers, Group B of 20 firemen, Group C of 24 policemen, Group D of 34 airline ground staff, and Group E of 14 civil servants. The typical audiogram pattern of noise-induced hearing loss (NIHL) was a dip at 3 or 4 kHz and moderate hearing loss in the frequency range of 6 to 8 kHz. The results of audiograms in this study revealed the prevalence rate of high-frequency loss in all employees was 41.9%. The incidences of NIHL were highest in the groups of maintenance workers (65.2%) and firemen (55.0%), who are almost continuously exposed to aircraft noise. As for the BAEPs, both click threshold and latencies showed that the impairment was most severe in the groups of maintenance workers and firemen. There was prolongation in central conduction time, shown mainly in intervals of I-V and III-V. This suggests that involvement of the central auditory pathway, especially between the pons and midbrain, is present. In summary, the degree of auditory damage coincided with job patterns. Furthermore, damage of both peripheral cochlear organs and the central auditory pathway by high-frequency aircraft noise exposure was confirmed.

Adult↗

PubMed1991

Generator study of brainstem auditory evoked potentials by a radiofrequency lesion method in rats.

The generators of brainstem auditory evoked potentials (BAEPs) in rats were investigated experimentally. Discrete lesions of the brainstem auditory pathway were made unilaterally using a stereotaxic radiofrequency coagulation method, and the BAEPs were recorded before and after the lesions to observe the alterations. The waves of the BAEPs were affected by the lesions as follows: (1) all of the BAEP waves were attenuated or eliminated by a lesion of the auditory nerve; (2) wave II was abolished or attenuated in amplitude following a lesion of the cochlear nucleus; (3) marked reduction or abolition of wave III occurred with some effect on waves IV and V following lesions of the superior olivary complex; (4) the following trough in the wave III was significantly attenuated by lesions of the lateral lemniscus that were associated with inconsistent changes in waves IV and V; (5) no waves were affected significantly by a lesion of the inferior colliculus. The method of radiofrequency lesion using stereotaxic localization proved to be a simpler and more rapid procedure for determining the generators of BAEPs in animals than other surgical lesion methods.

Animals↗

PubMed1991

Prednisolone withdrawal followed by recombinant alfa-interferon in chronic non-A, non-B hepatitis: interim results of a randomized controlled trial.

To determine the effect of a recombinant alpha interferon 2b (Intron-A) and possible benefit of prednisolone pretreatment in chronic non-A, non-B hepatitis, 75 Chinese patients with clinico-histologically proven chronic hepatitis were randomly allocated to one of the following regimens: (A) 3 million units of Intron-A trice weekly for 6 months; (B) dose titration according to ALT-AST values; (C) prednisolone withdrawal followed by regimen A; (D) control group: no treatment for 6 months but followed by alternating treatment with 3 million units of Intron-A trice weekly for 2 weeks followed by 2 weeks no treatment for 6 months. Up to September 30, 1990, 67 patients have been followed for a minimum of 2 months. At the end of the second month, complete response (normal ALT) was achieved in 71% of group A, 50% of group B, 50% of group C and 0% of group D. At the end of the 6th month, the complete response rate was 62%, 47% and 64% respectively in groups A, B and C. The response rates in groups A and C were significantly better than the 7% in the control group. Complete response usually (91%) occurred within 2 months after the first dose of interferon. Relapse occurred in 40% of the complete responders, usually within 2 months of the last dose. The cumulative relapse rate was significantly lower in responders of group C (11% vs 43% in group A and 86% in group B during a period of 6 months). Only mild adverse effects were reported though two patients withdrew because of intolerable fatigue.(ABSTRACT TRUNCATED AT 250 WORDS)

Chi-Square Distribution↗

PubMed1991

Detection and distribution of aromatase in hypothalamus of the male rat.

Conversion of androgen to estrogen in the rat brain is catalyzed by aromatase. An in vitro assay for aromatase activity, which quantitates the production of 3H2O during the conversion of 1 beta-3H-androstenedione to estrone, was developed and validated in the present study. The distribution of aromatase activity in discrete hypothalamic nuclei was also explored. Individual hypothalamic nuclei were microdissected from 200-micron frozen sections. Tissues from 3 animals were pooled and assayed for aromatase activity. It was found that the rate of aromatase activity was linear with time up to 1 hour, and with protein concentrations up to 900 micrograms/ml tissue homogenate. A maximal rate was obtained with a substrate concentration of 0.3 microM. The aromatase activity was heterogeneously distributed within the rat brain. The greatest amount of aromatase activity was found in the preoptic area. The suprachiasmatic nucleus also contained a high level of aromatase activity. The aromatase activities in the anterior hypothalamus, ventromedial nucleus, arcuate nucleus and dorsomedial nucleus were less than half that found in the preoptic area.

Animals↗

PubMed1991

Protection of liver ischemia due to inflow occlusion using prior perfusion with hepatic protective solution in dogs.

Temporary occlusion of hepatic inflow is a useful maneuver to reduce hemorrhage from liver trauma and difficult hepatic resections. The liver can be protected with a hepatic protective solution before inflow occlusion, just as the stopped heart is protected by a cardioplegic solution during open heart surgery. Twenty dogs were divided into two groups. The portal inflow of group A was infused via the mesenteric venous branch with a hepatic protective solution composed of 250 mg of hydrocortisone, 15 mEq of KC1, 6 mL of 0.1 N HC1, 5 mL of 10% magnesium sulfate and 250 mg of dextrose in one liter of cold lactated Ringer's solution. Group B was infused with cold lactated Ringer's solution as a control. The hepatic artery and portal vein were isolated and then clamped for 30 minutes. The elevation of serum GOT and GPT after release of the clamps was significantly greater in group B, especially during the first 48 hours. The levels of alkaline phosphatase and total bilirubin were also higher in group B until the 7th day. The results liver biopsies 3 hours after release of the clamps revealed marked congestion and destruction of hepatocytes in group B. We conclude that liver perfusion with a hepatic protective solution before inflow occlusion results in less damage to liver tissue and less impairment of liver function. Such protection is important in liver surgery.

Animals↗

PubMed1991

Flow cytometric DNA analysis of hepatocellular carcinoma: preliminary report.

Flow cytometric DNA analysis was performed in 50 paraffin-embedded specimens of clinical hepatocellular carcinoma (HCC) after hepatic resections. The DNA distribution pattern was classified in two types, diploid and aneuploid, according to the degree of dispersion on the DNA histogram. The major DNA pattern of HCC in this report proved to be aneuploid (78%), although 22% of tumors revealed a diploid pattern. The serum alpha-fetoprotein level exceeded 40 ng/ml in 86.1% of the aneuploid tumors and in 13.9% of the diploid tumors (p less than 0.05). We found no correlation between DNA distribution and hepatitis B surface antigen positivity, the presence of liver cirrhosis or tumor size. Additionally we noted no significant correlation between the DNA pattern and survival rates in patients with HCC who underwent hepatic resection.

Adolescent↗

PubMed1991

Study of myopathy in chronic alcoholics with neurological complication.

This study was undertaken to understand the myopathic manifestations as well as the electrophysiological, pathological, and histochemical changes in muscle tissues of chronic alcoholics. Twenty eight cases of chronic alcoholics with neurological complications and confirmed myopathy were included in this study. Of these, 11 cases (39.3%) belonged to the subclinical forms with either Korsakoff-Wernicke encephalopathy or cerebellar atrophy. The remaining 17 cases (60.7%) were clinical forms with various manifestations, such as hypokalemic periodic paralysis, alcoholic rhabdomyolysis, vacuolar myopathy with phosphorylase deficiency, chronic proximal limb-girdle myopathy and neuro-myopathy. Electromyography (EMG) study showed both myopathic and neurogenic changes. The single fiber EMG revealed increased jitter and blocking rate suggesting reinnervation. In muscle biopsy, the histological and histochemical abnormalities included random atrophic fibers, necrotic fibers, fibers with internal nuclei, phagocytosis and moth-eaten fibers. There was selective atrophy of type 2 muscle fibers, particularly of type 2B fiber. Total or partial myophosphorylase deficiency was observed in some cases (33%). All these findings indicate typical myopathic changes, which might be caused by defects in the energy pathways, especially in the glycolytic processes. In some muscle specimens, there were angular atrophic fibers and fiber type groupings suggesting denervation and reinnervation changes. In conclusion, both myopathic and neurogenic alterations were frequently observed in muscles of chronic alcoholics.

Adult↗

PubMed1991

Incidence, determinants and significance of delayed clearance of serum HBsAg in chronic hepatitis B virus infection: a prospective study.

To investigate the incidence, determinants and significance of delayed clearance of serum HBsAg in chronic hepatitis B virus infection, a prospective follow-up study was conducted in two consecutive groups of patients. Group I consisted of 984 patients (859 men and 125 women) with biopsy-proven chronic type B hepatitis, whereas group II consisted of 1,598 asymptomatic chronic carriers (998 men and 600 women) with normal serum aminotransferase activity. During a mean follow-up period of 4.0 +/- 2.3 yr, 19 patients (1.9%) of group I cleared HBsAg from their serum, whereas 35 patients (2.2%) in group II did so in a mean follow-up period of 2.7 +/- 1.4 yr. The annual incidence of delayed serum HBsAg clearance was 0.5% in group I and 0.8% in group II (p less than 0.02). The cumulative probability of HBsAg clearance was also higher in group II than in group I (p less than 0.007). Antibodies to HBsAg developed in 9 patients (47.4%) with chronic hepatitis and in 11 (31.4%) asymptomatic carriers who cleared serum HBsAg. Those who were HBeAg negative and those older than 40 at entry and those who exhibited cirrhosis during follow-up had a higher incidence of delayed HBsAg clearance. Gender, initial histological changes and hepatitis delta virus infection did not influence the occurrence of HBsAg clearance. Serum HBV DNA was not detectable by slot-blot hybridization but was still detectable by polymerase chain reaction in serum specimens collected within 1 yr of HBsAg clearance. Liver biopsy performed later in 10 patients showed no significant hepatitis activity or tissue HBV DNA, HBsAg or HBcAg.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1990

Intrahepatic expression of HBcAg and delta antigen in anti-HBe positive HBsAg carriers with acute exacerbation or chronic active liver disease.

Intrahepatic expression of HBcAg and hepatitis delta antigen (HDAg) was studied in 43 patients with acute exacerbation AE and 37 with chronic active liver disease CALD, in order to evaluate the role of hepatitis B virus (HBV) replication and hepatitis delta virus (HDV) superinfection in development of AE or CALD in anti-HBe positive HBsAg carriers in Taiwan, and the results were compared with 37 patients with only minor hepatitic activity. Only 8.1% of patients with minor hepatitic activity were HBcAg positive, and none were HDAg positive. In contrast, 41.8% and 32.6% of patients with AE were positive for HBcAg and HDAg, respectively, and the other 25.6% were negative for both. The clinical features of AE showed no difference in relation to HBcAg and HDAg activity in the liver except that patients without HBcAg and HDAg were predominantly older adults. These patients might be supposed to have non-A, non-B hepatitis (NANB) virus superinfection, as many reports have shown a predominance of older patients in acute NANB hepatitis. Of the patients with CALD, 40.5% were HBcAg positive, 27.0% were HDAg positive, and 32.5% were positive for neither. Histological features of CALD were identified in 83.3% and 100% of patients with HBcAg and HDAg activity, respectively, but only in 26.1% of those without HBcAg and HDAg. The etiology of CALD in the latter group remains unclear. Furthermore, some of the anti-delta seropositive patients with AE or CALD expressed HBcAg rather than HDAg in the liver.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

Acute hepatitis delta virus superinfection in patients with liver cirrhosis.

A clinicopathologic study in a total of 164 patients with acute hepatitis delta virus (HDV) infection showed that nine male patients (5.5%) had evidence of liver cirrhosis prior to or during the episode of acute hepatitis. All nine patients had typical clinical presentations and laboratory findings of acute viral hepatitis. Four of them had prolonged prothrombin time, three developed ascites and one finally died of hepatic failure. Clinical ascites occurred more frequently in cirrhotic patients with severe but non-fulminant hepatitis than their non-cirrhotic counterparts (p less than 0.05). In addition, histologic studies in five patients with cirrhosis disclosed diffuse lobular necrotizing inflammatory activity, with four showing bridging hepatic necrosis, which also occurs more frequently in cirrhotic than in non-cirrhotic patients (p less than 0.05). The data suggest that HBsAg positive patients with cirrhosis are susceptible to acute HDV infection which may lead to extensive necrosis or even decompensation and failure, simulating decompensation of the underlying liver disease. Therefore, careful clinicopathologic work-ups are required for accurate diagnosis and correct assessment of their outcomes.

Acute Disease↗

PubMed1990

Jadassohn's nevus sebaceous of the head and face.

The nevus sebaceous is a congenital skin lesion that usually appears in the head and face area. The lesions often cause aesthetic problems for patients and have a high incidence of malignant degeneration. The nevus sebaceous is rarely discussed in plastic surgery literature, however. This article describes 62 cases with a review of the literature.

Adolescent↗

PubMed1990

Acute exacerbation in patients with liver cirrhosis: a clinicopathological study.

The incidence, clinicopathologic features and etiology of acute exacerbation occurring in patients with liver cirrhosis were assessed prospectively among 332 hepatitis B surface antigen (HBsAg) positive and 71 HBsAg negative patients. During an 11-year period and a mean follow-up duration of 26.8 months, 148 acute exacerbation occurred in 107 HBsAg positive patients and 32 episodes occurred in 18 HBsAg negative patients. The calculated annual incidence was 11.5%. The clinical, laboratory and histologic features were similar to those in patients with chronic hepatitis. Confluent hepatic necrosis and alphafetoprotein elevation over 100 ng/ml occurred frequently, particularly in HBeAg positive patients. In general, acute exacerbations in HBsAg negative patients were less severe than their HBsAg positive counterparts. Of the exacerbations in HBsAg positive patients, 54.8% of the HBeAg positive ones and 38.6% of the HBeAg negative ones were attributable to hepatitis B virus reactivation, while 4.8% and 7.9%, respectively, were due to hepatitis delta virus superinfection. The others might be the results of hepatitis non-A, non-B virus superinfection or increased piecemeal necrosis. The immediate outcome of acute exacerbations in cirrhotic patients was usually good, although 13.8% developed hepatic decompensation and 4.4% died. Further follow-up study is required to evaluate the long-term effect of the frequent occurrence of bridging hepatic necrosis, high elevation of alphafetoprotein and hepatic decompensation during acute exacerbation in cirrhotic patients.

Adult↗

PubMed1990

DNA measurements in chronic hepatitis, cirrhosis and hepatocellular carcinoma.

It has been documented that chronic hepatitis may progress to cirrhosis and then develop hepatocellular carcinoma (HCC). To test whether abnormal cellular DNA increases along this line of development, liver tissues from 48 patients with chronic hepatitis, 17 with cirrhosis, and 8 with HCC were investigated for cellular DNA content with a scanning microdensitometer. Seven of 8 HCCs and 2 cirrhotic livers adjacent to HCC had abnormally increased cellular DNA content. Only 4 livers from patients with chronic liver diseases other than HCC had abnormal cellular DNA content. The cellular DNA content in livers not accompanying HCC was not related to the patient's age, histological diagnosis, and hepatitis inflammatory activity. The results confirmed the increase of cellular DNA content in HCC, but did not provide evidence of a progressively increasing DNA content from chronic hepatitis to liver cirrhosis. However, cirrhotic livers with abnormal hepatocytic DNA content deserve careful follow-up for the early detection of HCC.

Adult↗

PubMed1990

Brain stem auditory-evoked potentials in different strains of rodents.

This study was conducted to evaluate variations in brain stem auditory-evoked potentials (BAEPs) among different strains of rodents. BAEPs were recorded by routine procedures from rodents of different strains or species. These included 22 Long-Evans, 28 Wistar and 28 Sprague-Dawley rats, and six hamsters. Within the first 10 ms, there were five consistent and reproducible positive waves of BAEPs in each rodent, named I, II, III, IV and V in correspondence with the nomenclature of waves I-VII in human BAEPs. These BAEPs were also similar to those observed in other vertebrates and in human controls. However, there were variations in waveforms and peak latencies among rodents, even in the rats of the same strain that came from different laboratory centres. At optimal stimulation intensity, usually around 90 dB, the mean latencies of the waves varied as follows: I, 1.23-1.53 ms; II, 1.88-2.28 ms; III, 2.62-2.94 ms; IV, 3.49-3.97 ms; and V, 4.47-5.14 ms. They were significantly different between species, but not in different strains of rats if they came from the same animal centre. The conduction time in the central portion illustrated by interpeak latencies between I and III, III and V, and I and V was dependent on the species (P less than 0.05). When recorded in a soundproof incubator, the minimal hearing threshold showed a significant species difference. The animal BAEP model can be employed for evaluating the physiological function or the pathological conditions of the brain stem. The confirmation of BAEP variations among different species or strains will be helpful in deciding which kind of rodents will be appropriate to serve as animal models for the various purposes of BAEP studies.

Animals↗