Biomedical subjects

T J Chen

Publications and source records attributed to T J Chen.

At least 19 recordsLinked to original sources

PubMed1995

Outcome of very low birth weight infants in industrialized countries: 1947-1987.

Neonatal intensive care has led to a progressive improvement in the survival of very low birth weight (VLBW, < 1,500 g) infants. However, it has not been established whether there has been a simultaneous increase or decrease in the prevalence of handicapping conditions in this group of children. To explore this question, a meta-analysis was performed using outcome data of 32 developmental studies of VLBW infants born in industrialized countries between 1947 and 1987. The authors' results show that the proportion of VLBW infants who survived and had an intact outcome progressively increased between 1947 and 1987--from 147 per 1,000 live births in the period 1947-1965 to 498 per 1,000 in the period 1980-1987 (p < 0.01). The prevalence of major handicapping conditions for the subset of VLBW infants who weighed < 1,000 g at birth increased, resulting from the increasing survival rates. However, the prevalence of major handicapping conditions among all children with VLBW decreased from 147 per 1,000 live births in 1947-1965 to 45 per 1,000 in 1980-1987 (p = 0.02). The authors' meta-analysis suggests that improved survival of VLBW infants has not been accompanied by an increase, but more likely a decrease, in the prevalence of handicapping conditions in this birth weight group.

Cohort Studies↗

PubMed1995

Effects of fetal brain grafting on adult behavioral masculinization and defeminization in neonatally androgenized female rats.

Treatment of neonatal female rats with androgen results not only in decreased female sexual behavior but also in enhanced male sexual behavior examined in adulthood. The effects of grafting fetal preoptic area (POA) neurons into the POA, and fetal hypothalamic (HPT) neurons into the ventromedial hypothalamus (VMH), were tested in neonatally androgen-sterilized rats (ASR). The rats were injected subcutaneously with 80 micrograms testosterone propionate within the 24 hours after birth to see if sexual behavior could be normalized by fetal brain grafts. In repeated tests on ASR grafted with fetal HPT into the VMH, the lordotic response was seen to increase to the level seen in non-ASR controls, while the increase in mounting behavior in ASR was suppressed following grafting of fetal POA or cerebral cortex into the POA. These results suggest that there are dysfunctions of POA and VMH in ASR, and that the dysfunctions revealed by sexual behavior can be overcome by fetal POA or HPT grafting.

Androgens↗

PubMed1995

Dopamine D2 receptor gene variants: association and linkage studies in impulsive-addictive-compulsive behaviour.

Drug and alcohol seeking behaviour has become a great global problem affecting millions of inhabitants with a cost to society in the billions. Dopaminergic reward pathways have frequently been implicated in the etiology of addictive behaviour. While other neurotransmitters have also been implicated, to date the only molecular genetic defect which has been found to associate with alcoholism, drug dependency, obesity, smoking, pathological gambling, attention-deficit-hyperactivity disorder (ADHD), Tourette syndrome, as well as other related compulsive behaviours, are the variants of the dopamine D2 receptor gene (DRD2). In this review of the available data on the subject, we report a number of independent meta-analyses that confirm an association of DRD2 polymorphisms and impulsive-additive-compulsive behaviour (IACB), which we have termed "Reward Deficiency Syndrome". While we agree that Meta-analyses of all exant studies support an association of variants of DRD2 and IACB, correct negative findings with alcoholism may be due to differences in assessing controls and inclusion/exclusion criteria for selection of diseased probands.

Behavior, Addictive↗

PubMed1995

[Locomotion of dystrophin-deficient mice].

The purpose of our study was to make a comparison of the motor function between murine dystrophy mice (MDX mice) and C57BL/10ScSn control mice. The locomotor activities of mice were measured by an animal three-dimension optical monitor. Measurements were performed at ages of 21, 45 and 60 days. Animals were tested in a dark and peaceful environment under room temperature (25 degrees C-27 degrees C) at night for an hour. Results showed that the most important differences were in data on vertical activities. Among 15 variables of locomotor activity detected by the optical activity monitor, the MDX mice and control mice at age 21 days showed significant differences in 12 variables. However, the MDX mice and control mice at age 45 days revealed significant differences in only 7 variables. The MDX mice and control mice at age 60 days had significant differences for only one variable. The results may be explained by the fact that dystrophin-deficient mice undergo more severe dystrophic degeneration at an early age (5 weeks) and new regeneration of their muscle fibres is prevalent. Moreover, a functional recovery occurred in MDX skeletal muscle which was probably due to the regeneration of dystrophic muscle.

Age Factors↗

PubMed1995

[Study of myoblast culture and myoblast transfer therapy in dystrophic mice].

In this report, we study the suitable conditions for myoblast cultures through analysis of myoblast growth and differentiation, and then try to develop a mouse model for myoblast transfer therapy (MTT). Recently, some research has indicated that Muscular Dystrophy Murine Mice (MDX) have an X-linked recessive dystrophin deficiency which is caused by dystrophin gene point mutation at the X chromosome. Therefore, MDX mice are usually used for MTT models of muscular dystrophy disease. Control mice, C57BL10/SCSN (B-10) were chosen as a source of normal myoblasts. Myoblasts isolated from the hindlimb muscle tissues of two- to three-day-old neonatal B-10 mice were cultured in vitro for one to seven days. Through our modifyied techniques of isolation and culturing conditions, a myoblast purity of 70% could be achieved, with fibroblast the only contaminating cell type. The proliferative capacity and the doubling time of myoblasts were counted from analysis of growth kinetics. While differentiative capacity was analyzed morphologically, we found the fusion of myoblasts was time-dependent. Immunostaining myoblasts of different stages with anti-dystrophin antibody showed that purified myoblasts with the capacity of fusion can express dystrophin and can be utilized as a donating source in MTT. In the MTT experiment, eight young MDX mice were injected with normal myoblasts at a concentration of 1 x 10(6) cells. All transplated mice received daily cyclosporine A injection for immunosuppression. Two to three months later, dystrophin was found in the myoblast-transferred muscles while staining immunocytochemically. The result suggests that we successfully transferred the normal dystrophin gene from the normal myoblasts into the MDX mice since their myoblast-injected muscle could express dystrophin.

Animals↗

PubMed1994

[Cholangiocarcinoma with mucobilia].

Mucobilia is a rare condition, with copious mucus secretion within the extrahepatic bile ducts resulting in obstructive jaundice and cholangitis. Fifteen patients with mucobilia were treated over an 11 year period. Preoperative study included ultrasonography (15), cholangiography (15), liver scanning (2) and computed tomographic (CT) scanning (1). The diagnosis was made preoperatively in 26.6% (4/15) of the patients. The preoperative diagnosis was based on 1) mucinous substance draining out from the papilla after endoscopic cannulation or percutaneous transhepatic biliary drainage fistula 2) multiple amorphous filling defects of the bile duct on cholangiograph 3) biliary duct dilatation with an intrahepatic or liver tumor on image study (sonography or CT scan). The etiology of mucobilia was papillary cholangiocarcinoma in 10 patients, biliary cystadenocarcinoma in three patients, and cystadenocarcinoma of the liver in another two. Intraoperative choledochoscopy revealed an intrahepatic biliary tumor in seven patients, intrahepatic duct stricture or obliteration in six and normal findings in another two. Surgical treatment of the 15 patients included left hepatectomy with choledochotomy in eight and choledochotomy with tumor biopsy in another seven patients. One patient died after T-tube drainage due to septic shock for a 6.6% mortality rate. Postoperative follow-up revealed the continuous drainage of a mucinous substance from the T-tube fistula receiving regular choledochoscopic irrigation in six patients. Four cholangiocarcinoma patients with mucobilia were effectively controlled by external radiation and intraluminal radiation therapy. The overall survival time ranged from 9 months to 11 years 6 months (mean, 46 months). Three patients (20%) are still surviving more than 5 years post diagnosis.

Aged↗

PubMed1994

Effects of age on open-field behavior of male rats.

As age advances, the performance of animal behavior declines gradually. The purpose of this study was to investigate the onset of age-related changes in open-field behavior of rats from a wide age spectrum. Male Long-Evans rats, ranging from 2 to 22 months, were placed in an open-field apparatus during the dark phase for a cumulative period of 28 min. Data were collected for the following parameters of open-field behavior: horizontal activity (HA), total distance (TD), stereotypy count (SC), vertical activity (VA), movement time (MT) and margin time (MGT). The highest value of HA, TD, SC and MT was found in rats at the age of 3 months. After 3 months, the values for these parameters gradually declined, subsequently reaching statistical significance by 6 months (HA, TD and SC) or 8.5 months (MT) of age. Maximum activity of VA occurred at 8.5 months of age and thereafter gradually declined with increasing age, however, no significantly statistical difference was reached as compared to the highest value. In contrast, the values for MGT gradually declined after 2 months of age, thereby reaching statistical significance by 11 months of age. These results indicate that the onset of age-related decline in open-field behavioral parameters can differ and the age-related changes in open-field behavior depends on observational parameters.

Age Factors↗

PubMed1993

Augmentation of liver regeneration with glucagon after partial hepatectomy in rats.

The direct stimulating effect of glucagon on partially hepatectomized rats was studied. Following a 70% hepatectomy, male Wister rats were divided into three groups. Group I received glucagon 0.8 mg/kg/day; group II received hydrocortisone 10 mg/kg/day; and group III received normal saline as a control. Their blood sugar levels and food intake were not significantly different. After one week, the regenerated livers in group I were larger (9.69 +/- 0.30 cm3 vs 8.29 +/- 0.34 cm3 in group II and 8.20 +/- 0.10 cm3 in group III), and heavier (9.83 +/- 0.28 g vs 8.52 +/- 0.33 g in group II and 8.75 +/- 0.21 g in group III) than those in the other two groups. The mitotic index in group I was also higher. The results suggest that glucagon has a direct hepatotrophic effect and enhances regeneration of the liver in rats.

Animals↗

PubMed1992

Estrogen and osteoarthritis: a study of synovial estradiol and estradiol receptor binding in human osteoarthritic knees.

Estrogen appears to be a risk factor in knee osteoarthritis (OA). Results from 21 patients revealed that synovial estradiol level was highly related to the severity of OA. Increased estradiol receptor bindings in the medial compartment of the femoral condylar and tibia plateau cartilages were observed; the increase was significantly higher in the medial than in the lateral compartment (p less than 0.05). Although the synovial estradiol level was significantly lower in women with OA than in men with OA (p less than 0.01), postmenopausal women were hypothesized to be more susceptible to OA, since the possible existence of synovial testosterone might counteract the high estradiol synovial level in men, which results in a lower incidence of knee OA in men than in postmenopausal women. We suggest that excessive synovial estradiol and higher estradiol receptor bindings may be involved in the development of knee OA, particularly in postmenopausal women.

Aged↗

PubMed1992

Concurrent hepatitis C virus and hepatitis delta virus superinfection in patients with chronic hepatitis B virus infection.

Since hepatitis C virus (HCV) and hepatitis delta virus (HDV) are transmitted by the same routes as hepatitis B virus (HBV), simultaneous or concurrent HCV and HDV infection in patients with chronic HBV infection may occur. To test this hypothesis and to examine the clinicohistological and immunopathological presentations of such multiple hepatitis virus infections, acute and/or convalescent serum specimens from 86 patients with acute HDV superinfection were tested by enzyme immunoassay for antibodies to HCV. Of the 86 patients, 18 (20.9%) were associated with HCV infection. Although patients with early mortality cannot be evaluated by the HCV markers used in this study, the results showed that the clinical and histologic features were similar except that patients with HCV infection were older than those without HCV infection (P less than 0.01). Immunopathological studies carried out within 2 months after the onset of acute HDV superinfection demonstrated that hepatitis B core antigen (HBcAg) was not detected in any patient and HDV antigen was detected in 18.2% of the patients with HCV infection whereas HBcAg and HDAg were found in 7% and 65.1%, respectively, of those without HCV coinfection (P less than 0.02). It is concluded that concurrent HCV and HDV superinfections can and do occur in patients with chronic HBV infection. In these triple viral infections, HCV may even transiently suppress HDV and HBV.

Adult↗

PubMed1992

Progesterone regulation of progesterone receptor in mesometrial and antimesometrial deciduoma in pseudopregnant hamster.

Experiments were performed to examine the trophic effects of progesterone (P) on the progesterone receptor (PR) and the maintenance of the deciduoma. Deciduomal reactions in response to artificial stimuli were induced in hamsters' uteri on the 4th (D4) day of pseudopregnancy (PSP). On and after the 8th day, PSP hamsters received P supplement (2mg; s.c.) daily. Histological observation revealed that the life span of the deciduoma was partially prolonged. The maintenance and regression of the deciduoma was heterogeneous. P was able to maintain the morphology of the cells at the mesometrial site (MS) on D12, whereas cells at the antimesometrial site (AMS) regressed. The cytosol progesterone receptor (cPR) concentration in cells of the MS was higher than that of the AMS on D10. The cPR in MS and AMS decreased drastically on D12. The nuclear PR (nPR) remained at a higher concentration in both tissues on D10 followed by a precipitous decrease. The deciduomal nPR in the AMS decreased at a faster rate. By day 12, the nPR in the MS was much higher than that in the AMS. These data show that P acts as a trophic hormone of the deciduoma. The maintenance of deciduoma is closely related to the presence of PR. Other mechanisms may exist for the heterogeneous responses observed at the MS and AMS.

Animals↗

PubMed1992

Sex differences in estrogen and androgen receptors in hamster brain.

The present study was conducted to measure the levels of estrogen and androgen receptors (ER and AR, receptively) simultaneously in the anterior pituitary (AP), and various brain regions from adult male and proestrous female hamsters. Medial preoptic area (MPOA), medial basal hypothalamus (MBH), lateral hypothalamus (LH), medial forebrain bundle (MFB), and amygdala (AMG) were identified and removed from 200-microns frozen brain sections by the Palkovits punch-out technique. ER and AR were determined by the in vitro binding assay using [3H]-estradiol and [3H]-methyltrienolone as the binding ligands. In males, high levels of AR were found in the MPOA, MBH, and AP. In females, the MPOA, MBH, LH, and AP contained high levels of ER. The males exhibited significantly higher levels of AR than females in the MPOA, MBH, and LH, whereas the ER levels in these areas were higher in females. In males, ER and AR contents in the AP were higher, but the contents in the AMG were lower as compared to those of females. The calculated ER/AR ratio in MPOA, MBH, and LH were lowest in males. On the contrary, the ratio in these areas were highest in females. These data suggest that sex differences in response to estrogen and androgen may in part be due to sex differences in ER and AR contents in specific brain regions.

Animals↗

PubMed1992

Effects of anterior roof deafferentation on lordosis behavior and estrogen receptors in various brain regions of female rats.

This study investigated whether the estrogen receptors (ER), located at different brain areas and anterior pituitary (AP), changed after anterior roof deafferentation (ARD), and on the effects of facilitating the lordosis reflex in female rats. Female rats were ovariectomized and implanted with estradiol capsules. ARD or sham operation was performed with a Halász knife. All animals were tested for lordosis both before and after surgery. One day after the last test they were sacrificed. Cytosol and nuclear ER in the AP, medial preoptic area (MPOA), basal medial hypothalamus (BMH), amygdala (AMYG), septum (SEP), hippocampus (HPC), and cortex (CTX) were measured using an in vitro exchange assay. Rats with ARD showed significantly higher mean levels of lordosis quotient than the control and the sham groups before ARD surgery. An increase of both cytosol and nuclear ER in the BMH area compared to the control was observed, whereas the ER, in the SEP was reduced. ER in other areas were not affected by ARD. Serum estradiol and progesterone levels were not altered by the operation. These data suggest that the dorsal inhibitory pathway from the extrahypothalamus to the preoptic area and hypothalamus may modulate the estrogen receptor and the display of lordosis in female rats. Change of ER level in the BMH area may influence the hormonal sensitivity of lordosis in female rats.

Animals↗

PubMed1992

Hepatitis B X-gene expression in hepatocellular carcinoma.

A RNA-PCR method and different sets of primers were used to investigate the expression of different hepatitis B (HB) virus genes at the RNA level. We tested paired samples (tumor and non-tumor) from the liver tissues of 48 Taiwanese patients with primary hepatocellular carcinoma (HCC). By using a set of primers which spanned the sequences of the S-gene, we found expression in only 2 patients. In one HBs-RNA was only detected in the tumor tissue and in the other only in the surrounding non-tumor tissue. Using primers covering the C-gene, expression was found in 7 patients. In 2 of these RNA was detected in both the tumor and the surrounding tissue, in 2 in the tumor tissue, and in 3 in the surrounding tissue only. Finally, when primers spanning the X-gene sequences were used, RNA was detected in 40/48 patients. In 33 of these cases HBx-RNA was detected in both tumor and non-tumor tissue, in 3 patients in tumor tissue only, and in 4 in the surrounding tissue. Among the cases in which HBc and HBs-RNA was expressed, all showed HBx expression also. These data indicate that the expression of the HBx gene in HCC may play an important role in hepatocarcinogenesis.

Base Sequence↗

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↗