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Biomedical subjects

H C Chang

Publications and source records attributed to H C Chang.

At least 181 records · Page 10Linked to original sources
PubMed1992

[The effect of monosodium L-glutamate (MSG) treatment during neonatal period on the pineal function in young female rats].

The purpose of this study is to examine whether monosodium L-glutamate (MSG) influences the function of pinealocytes in female rats. MSG was administered at a does of 4 mg/g body weight to rat pups on days 1 and 3 postnatally. As the rats matured, sexual receptivity as well as proceptivity were observed by testing the lordosis quotient (LQ), rejection quotient (RQ) and solicitation. Pineal function was estimated by measuring the serum level of melatonin and the activity of protein kinase A (PKA) in the pineal gland. Blood samples were withdrawn at light and dark phases for four consecutive days, respectively. The serum concentration of melatonin was determined by radioimmunoassay and the data of each phase were pooled together. The results showed that both the receptivity and proceptivity of MSG-treated female rats were significantly lower than that of the control ones. Melatonin levels during the dark phase were significantly higher than those during the light phase in both control and MSG-treated groups, but whenever in the light or dark phase, the levels of melatonin were the same in both groups. There was no significant difference in PKA activity in the pineal gland between the control and MSG-treated group. These results indicate that MSG used as a neurotoxin to induce hypogonadal status affected neither the PKA activity of pineal gland nor the serum level of melatonin in young female rats. Thus, the decrease in receptivity and proceptivity of MSG-treated female rats was not caused by the alteration of pineal function.

Animals↗
PubMed1992

Abdominal embryonal rhabdomyosarcoma. A case report.

Rhabdomyosarcoma is the most common soft tissue sarcoma in childhood, but it is rare in young adults. It usually occurs in the pelvis or genito-urinary tract. We report a case of abdominal embryonal rhabdomyosarcoma who received a combined treatment modality with radical pelvic surgery and combination chemotherapy of vincristine, actinomycin-D and cyclophosphamide (VAC). She is well with no evidence of tumour recurrence for 3 years after primary surgery.

Abdominal Neoplasms↗
PubMed1991

Chronic lithium regulates the expression of adenylate cyclase and Gi-protein alpha subunit in rat cerebral cortex.

A possible role for adenylate cyclase and guanine nucleotide-binding proteins (G proteins) in contributing to the chronic actions of lithium on brain function was investigated in rat cerebral cortex. It was found that chronic treatment of rats with lithium (with therapeutically relevant serum levels of approximately 1 mM) increased levels of mRNA and protein for the calmodulin-sensitive (type 1) and calmodulin-insensitive (type 2) forms of adenylate cyclase and decreased levels of mRNA and protein for the inhibitory G-protein subunits Gi alpha 1 and Gi alpha 2. Chronic lithium did not alter levels of other G-protein subunits, including Go alpha, Gs alpha, and G beta. Lithium regulation of adenylate cyclase and Gi alpha was not seen in response to short-term lithium treatment (with final serum levels of approximately 1 mM) or in response to chronic treatment at a lower dose of lithium (with serum levels of approximately 0.5 mM). The results suggest that up-regulation of adenylate cyclase and down-regulation of Gi alpha could represent part of the molecular mechanism by which lithium alters brain function and exerts its clinical actions in the treatment of affective disorders.

Adenylyl Cyclases↗
PubMed1991

Enhancement of amniocyte growth on a precoated surface.

This study investigates whether cell-free amniotic fluid facilitates cell attachment to the surface of culture plates and thereby promotes rapid amniocyte growth. Isolated or pooled cell-free amniotic fluid samples at different volumes were added to culture plates. Trypsinized subcultures, grown in Eagle's minimum essential alpha medium supplemented with fetal bovine serum (4-20 per cent), were monitored by cell counts. The results demonstrated growth stimulation on culture plates precoated with amniotic fluid. The minimal time for coating the culture plates was 6 h. Maximal coating was observed after an overnight incubation with 2-3 ml of the fluid per culture vessel. No synergistic effect from addition of fetal bovine serum to amniotic fluid was observed. A freshly coated surface provided the best amniocyte growth. When primary cultures are grown on a precoated surface, there is an increase in colony counts in 80 per cent of the samples tested. This method may be used to improve amniocyte growth, especially in samples with relatively small numbers of cells.

Age Factors↗
PubMed1991

Immobilized-enzyme electrode for nicotinamide adenine dinucleotide (reduced form) (NADH) sensing and application to the kinetic studies of NADH dependent dehydrogenases.

Amperometric determination of nicotinamide adenine dinucleotide (reduced form) (NADH) at an immobilized-diaphorase (Dp) electrode is described. The measurement was conducted using ferrocenylmethanol as a mediator in a stirred solution at 0.20 V versus a saturated calomel electrode. A linear relationship between the steady-state current and the concentration of NADH was found over the range 0.005-0.125 mmol dm-3. The immobilized-Dp electrode showed outstanding stability and the current response reached a steady state within 2-3 seconds upon addition of NADH. The proposed electrode was used to follow the reactions of pig heart lactate dehydrogenase and horse liver alcohol dehydrogenase. The kinetic investigation using the immobilized-Dp electrode gave the kinetic parameters (Michaelis constants, Km values, and maximum velocities, Vm values), which were in satisfactory agreement with those determined by a conventional spectrophotometric method.

Electrodes↗
PubMed1991

Malignant mixed müllerian tumor of the fallopian tube. Case report and review of the literature.

Malignant mixed müllerian tumor of the fallopian tube is extremely rare, with less than 50 cases recorded in the English literature. Another case is reported and discussed. This 66-year-old female patient complained of profuse watery vaginal discharge for one month. Vaginal cytology was positive for malignancy while the endometrial curettage and cervical biopsy were both negative. Gynecologic sonography revealed a left adnexal mass of 6 cm in diameter. She underwent exploratory laparotomy after complete oncologic survey. The main tumor was confined to one tube but the peritoneal washing cytology was positive for adenocarcinoma cells. She tolerated the maximal debulking surgery very well but refused to receive adjuvant chemotherapy. Pathology proved that the tumor was composed of poorly differentiated adenocarcinoma and sarcoma. There were focal areas of rhabdomyoblastic differentiation with cross striation in immunoperoxidase stain. Carcinomatosis peritonii occurred 12 months after primary surgery and she expired one month later.

Aged↗
PubMed1991

Prognostic factors of stage Ib cervical carcinoma treated by radical abdominal hysterectomy.

From 1982 to 1984, 189 patients with stage Ib carcinoma of the uterine cervix underwent radical abdominal hysterectomies as primary treatment at Chang Gung Memorial Hospital. Of these patients, six were lost to follow-up. Nineteen of the 183 patients with regular follow-up recurred at intervals of from 9 to 55 months. An assessment of prognostic factors was made by reviewing the chart and pathological findings and correlating them with the patient's present status. Using univariate analysis, bulky tumor size was found to bear the greatest risk of tumor recurrence. Six of the 15 patients (40%) with a diameter of more than 4 cm recurred. The other risk factors included parametrial involvement, histologic type of adenosquamous or adenocarcinoma, lymph node metastasis, poor differentiation, deep cervical stromal invasion, and lymphatic or vascular space invasion. In conclusion, analysis of prognostic factors identified a group of patients at high risk of recurrence and decreased survival, for whom prospective trials of adjunctive treatment should be considered.

Adenocarcinoma↗
PubMed1991

[Intravenous propofol as a supplement in epidural anesthesia].

Under study were thirty patients of ASA class I-II scheduled for lower abdominal and lower extremities surgery. Premedication included intramuscular injection of pethidine, atropine and prochlorperazine. Epidural anesthesia was accomplished with 12-15 ml 2% lidocaine with epinephrine (1:80,000). Thirty minutes later, when blood pressure returned to control value, patients were put to sleep by 2 mg/kg propofol and the sleep was maintained with continuous infusion of propofol at a rate of 6 mg/kg/h. Infusion rate was adjusted when necessary. Patients breathed room air spontaneously through the whole course of anesthesia. The results showed that all patients fell to sleep within 28.3 +/- 2.7 s after intravenous injection of propofol 2 mg/kg. Sleeping dose was satisfactorily achieved using a mean infusion rate of 6.1 +/- 1.7 mg/kg/h. The mean time from the end of the infusion of propofol to opening of the eyes on command and telling the correct date of birth were 7.9 +/- 2.8 min and 9.9 +/- 3.8 min respectively. Two minutes after injection, there were significant decrease in systolic pressure, diastolic pressure, cardiac output, and stroke volume with a mean of 17.9 +/- 3.8%, 18.8 +/- 3.3%, 7.6 +/- 0.5% and 11.1 +/- 1.9% respectively. Two patients (7%) developed apnea after 2 mg/kg propofol which was considered to be the most serious side effect. Propofol infusion had to be stopped in 13% patients due to a 30% fall of arterial blood pressure during maintenance. In the recovery stage, no other complications were noted except one patient who felt dizziness. Propofol, used as the supplementary sedative, provides satisfactory result for surgery under epidural anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[The action mechanism of the pineal gland in inhibiting sexual receptivity of female rats: (I). Is it concerned with the extrahypothalamic inhibitory pathway?].

Monosodium L-glutamate (MSG), as a neurotoxin, was administered subcutaneously at a dose of 4 mg/g body weight to rat pups on days 1 and 3 postnatally. The sexual receptivity expressed as lordosis quotient (LQ) in MSG-treated female rats (2.5 months old) was significantly lower than that of the normal female ones, and this poor sexual receptivity of MSG-treated females could be improved by pinealectomy at the age of six weeks. In order to investigate the relationship between the inhibitory role of the pineal gland and the extrahypothalamic inhibitory pathway, normal control and MSG-treated rats were ovariectomized and implanted subcutaneously with estradiol capsule (20% estradiol benzoate, in 2mm silastic tube) at the age of 2.5 months. Three days after implantation, sexual receptivity was observed. Then, the anterior roof deafferentation (ARD) was preformed one week later and the sexual receptivity in both groups was compared again. The results showed that there was no significant difference of the lordosis response between the MSG-treated and the control groups before ARD, and the level of restoration by ARD in LQ of MSG-treated rats was similar to that of the control group. It seems that the extrahypothalamic inhibitory pathway of sexual receptivity may not be influenced by neonatal MSG-treatment. Our previous results indicated that the behavioral sensitivity to estradiol was altered by ARD. However, in the present study, the lordosis responses of MSG-treated and pinealectomized female rats were not significantly different from that of the control group after ovariectomy and exogenous estradiol implantation. This means that the behavioral sensitivities to estradiol were not changed by MSG-treatment or pinealectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

The spectrum of beta-thalassemia mutations in Taiwan: identification of a novel frameshift mutation.

Seventy-four beta-thalassemia genes from 37 unrelated beta-thalassemia-major patients were systematically characterized by using PCR, dot-blot hybridization, and direct sequencing of amplified genomic DNA. We found that six mutations--namely, II-654, 41/42, -28, 17 beta, -29, and 27/28--were prevalent, accounting, respectively, for 45.9%, 28.4%, 10.8%, 10.8%, 1.4%, and 2.7% of studied patients. The 27/28 mutation has at codon 27-28 a cytosine insertion which has never been reported before. These results indicate that four oligo-probes (II-654, 41/42, -28, and 17 beta) allow allele-mutant determination by oligonucleotide analysis in 95.9% of this group of patients, and direct sequencing can be carried out for other samples. These data will facilitate the prenatal diagnosis of this disease by DNA analysis in Taiwan.

Alleles↗
PubMed1990

Reassociation of deoxyribonuclease II with the lysosomal membrane isolated from porcine spleen.

DNase II, bound to the lysosomal membrane of porcine spleen, can be extracted from the membrane with 0.4 M NaCl. Reassociation of DNase II with the salt-extracted lysosomal membrane is readily accomplished in 0.01 M sodium acetate (pH 4.5). The reassociable amount of DNase II is approximately equal to the extractable amount. The capacity of the lysosomal membrane to bind DNase II is unaffected by the subtilisin treatment of the membrane. Phosphatidyl serine can bind DNase II as well, but with a much higher capacity. The erythrocyte plasma membrane on the other hand binds only about 20% of DNase II bound to the lysosomal membrane. The DNase II activity can be eluted from a column of the lysosomal membrane entrapped in 2% agarose and the elution pattern is very similar to that of CM-cellulose chromatography of DNase II, suggesting that electrostatic interactions may play an important role in the binding. The pH-reassociation profile is bell-shaped and is similar to the pH-activity profile of DNase II, having a maximum near pH 5. Under the nondenaturing condition, the dissociated alpha and beta subunits of DNase II cannot be reassociated to regain the enzymatic activity with or without the lysosomal membrane.

Animals↗
PubMed1990

Involvement of the PPPGHR motif in T cell activation via CD2.

Prior studies identified a segment of the CD2 cytoplasmic domain between amino acid (aa) residues 253 and 287 as important in T lymphocyte signal transduction. This region contains two repeats of the sequence motif PPPGHR, thought to form a "cage" structure involved in CD2-mediated signaling. To evaluate this segment, a series of mutant human CD2 molecules were produced by oligonucleotide-directed mutagenesis and inserted into the ovalbumin-specific, I-Ad-restricted murine T-T hybridoma 3DO54.8 using the DOL retroviral system. CD2 M1 (271-272), CD2 M2 (278-279), and CD2 M4 (264-265) mutants replaced the positively charged adjacent aa histidine and arginine (HR) in the wild-type CD2 sequence with aspartic and glutamic acid (DE) at positions 271-272, 278-279, and 264-265, respectively. In addition, a truncation mutant, CD2 M3 (268), containing only 57 of the 117 cytoplasmic aa and terminating before the second PPPGHR sequence, was generated. Stimulation of transfectants CD2 FL, CD2 M1 (271-272), and CD2 M2 (278-279) with anti-T11(2) + anti-T11(3) antibodies resulted in a rise in cytosolic-free calcium [( Ca2+]i) and subsequent interleukin 2 (IL-2) secretion. In contrast, CD2 M4 (264-265) transfectants could not be activated in either assay. Thus, alteration of histidine 264 and/or arginine 265 within the first PPPGHR motif affects the process of signal transduction via CD2, whereas identical mutations in residues at 271-272 or 278-279 were individually without effect. Consistent with these data, CD2 M3 (268) transfectants were able to generate a detectable amount of IL-2 via CD2 triggering. These data support the notion that the PPPGHR motif at aa 260-265 is important for activation of T lymphocytes via the CD2 molecule.

Amino Acid Sequence↗
PubMed1990

Electron transferase activity of diaphorase (NADH: acceptor oxidoreductase) from Bacillus stearothermophilus.

Electrochemical kinetic measurements were carried out for electron-transfer between NADH and the oxidized forms of mediators (ferrocenylmethanol (FMA), ferrocenyl-1-ethanol (FEA), N,N,N',N'-tetramethylphenylenediamine (TMPD), Co(Phen)2+(3) and Fe(CN)4-(6)) catalyzed by diaphorase (NADH: acceptor oxidoreductase, EC 1.6.99.-) purified from Bacillus stearothermophilus. Cyclic voltammograms for the mediators with excess NADH in the presence of diaphorase gave steady-state currents. The quantitative analysis of the dependence of the current on the mediator concentration yielded a Michaelis constant (Km) and molecular activity (ko), which are difficult to determine by the conventional spectrophotometric method. Small Km and large ko values were observed for the oxidized forms of FMA, FEA and TMPD compared to those for Co(Phen)3+(3) and Fe(CN)3-(6). It is suggested that the reaction pocket of the present diaphorase is hydrophobic. The present electrochemical procedure for the determination of the kinetic parameters is applicable widely to similar enzyme reactions.

Amino Acids↗
PubMed1990

Transrectal sonographic cystourethrography: studies in stress urinary incontinence.

Transrectal ultrasonic sagittal transducer is an excellent modality to image the bladder and urethra in dynamic change. In female patients, we found it is also helpful for the diagnosis of urinary stress incontinence. The posterior urethrovesical (PUV) angle is measured with the transrectal sonoprobe under strain and non-strain conditions. We compared the results of sonographic cystourethrogram with the radiographic chain cystourethrogram. The sonographic cystourethrography is superior to the radiography. The former may estimate the PUV angle accurately and differentiate between the patients with and without stress urinary incontinence. Furthermore, we also use the transrectal sagittal probe intraoperatively to adjust the suspension force as well as PUV angle in patients who underwent vesical neck suspension for stress urinary incontinence (SUI).

Adult↗
PubMed1990

Intraepidermal neutrophilic IgA dermatosis.

We report a patient with a vesiculopustular eruption with features distinct from typical subcorneal pustular dermatosis. Clinically, well-formed pustular lesions, which were flowerlike in appearance, were present. Histopathologically, early vesicular lesions showed intraepidermal bullae containing numerous neutrophils, a few eosinophils, and acantholytic cells. Direct immunofluorescence study revealed IgA deposits in the intercellular space of the epidermis. The patient's serum, however, did not contain circulating antibodies reactive with the epidermis. We consider this eruption an immunologically mediated, intraepidermal blistering disease, similar to intraepidermal neutrophilic IgA dermatosis.

Adult↗
PubMed1989

Müllerian adenosarcoma of uterus--a case report.

A rare case of Müllerian adenosarcoma occurred in the uterine endometrium of a 40-year-old woman. Histologically, the tumor was composed of an admixture of benign-appearing glands and a sarcomatous stroma. This neoplasm appears to have a relatively low malignant potential in contrast to the more aggressive form of malignant mixed Müllerian tumor. Our case was treated with hysterectomy and radiation. She was well after two and a half years.

Adult↗
PubMed1989

Dissection of the human CD2 intracellular domain. Identification of a segment required for signal transduction and interleukin 2 production.

To evaluate those residues in the 117 amino acids of the CD2 cytoplasmic domain required for transduction of T lymphocyte activation signals, a full-length human CD2 cDNA and a series of deletion and substitution mutants were inserted into the ovalbumin-specific, I-Ad-restricted murine T cell hybridoma 3DO54.8 using a retroviral system. The resulting cells express surface CD2 protein and unlike the parental murine line, are reactive with murine anti-human CD2 antibodies. Anti-T11(2) plus anti-T11(3) antibody stimulation of cells expressing a full-length CD2 cDNA results in a characteristic rise in cytosolic-free calcium [( Ca2+]i), and subsequent IL-2 secretion that accompany CD2 stimulation in human T lymphocytes. Transfectants expressing CD2 delta C98 and CD2 delta C77, partially deleted CD2 molecules containing the entire extracellular and transmembrane CD2 segments but only 98 and 77 amino acids of the cytoplasmic domain, respectively, are also activated by anti-CD2 mAbs. In contrast, clones expressing more severely truncated CD2 structures, CD2 delta C43 and CD2 delta C18, are not stimulated. These data show that the cytoplasmic domain plays an essential role in transduction of activation signals via CD2, and that the segment between amino acid residues 253 and 278 is necessary for activation. This region contains two tandem repeats of the sequence PPPGHR, thought to form part of a putative cationic site. Disruption of the latter by site-directed mutagenesis does not affect IL-2 gene induction, suggesting that only one of the repeats is required for activating this function of the CD2 molecule.

Amino Acid Sequence↗