Biomedical subjects

H C Chang

Publications and source records attributed to H C Chang.

At least 163 records · Page 9Linked to original sources

PubMed1994

Alveolar soft part sarcoma of the vagina. A case report.

We present a case of alveolar soft part sarcoma of the vagina in an 18-year-old woman. The presenting symptoms were menometrorrhagia and a painless vaginal mass. The tumor was in the vaginal stroma with intact mucosa. Periodic acid-Schiff stain showed positive diastase-resistant crystals in some of the tumor cells. Electron microscopy demonstrated characteristic intracytoplasmic crystals. Formaldehyde-induced fluorescence stain showed no catecholamines, and Grimelius stain showed no argyrophilic granules. Black pigment was found within some tumor cells; it proved to be melanin pigment by Masson-Fontana stain. The tumor mass recurred four months after local excision. Following the second surgical removal, the patient received adjuvant radiotherapy to the whole pelvis, including the vagina. At this writing she was currently alive, without evidence of recurrence, five years after the primary diagnosis.

Adolescent↗

PubMed1994

Small granule-containing (SGC) cells in the hamster adrenal medulla.

In addition to adrenalin (A)- and noradrenaline (NA)-containing cells in the hamster adrenal medulla, a third type of small granule-containing (SGC) cells was identified. These cells were characterized by their small size (about 15 microns in diameter) and location adjacent to A-cells. Numerous pleomorphic dense-cored cytoplasmic granules (306 +/- 44.5 nm x 204.5 +/- 58.3 nm, mean +/- standard error) were present in their cytoplasm. The ultrastructure of these granules were similar to that of NA-containing granules but smaller in size. The granular inclusions of the granules were moderate to high in electrol density. The cytoplasm of the SGC cells contained short profiles of rough endoplasmic reticulum and some free ribosomes.

Adrenal Medulla↗

PubMed1994

Lipopolysaccharide binding and antibacterial activities of a synthetic peptide representing amino acids 90-101 of bactericidal/permeability-increasing protein.

The bactericidal/permeability-increasing protein (BPI) of polymorphonuclear leukocytes is a potent antibacterial agent specific for gram-negative bacteria. BPI can bind to lipopolysaccharide (LPS) and neutralize its toxicity. However, little is known about the specific site and mechanisms of the BPI involved in this LPS binding and antibacterial activities. This study compared the amino acid sequences among BPI, cecropin A, magainin 2, and polymyxin B, and identified a common structure among these four bactericidal agents. They share a basic amphipathic alpha helix motif (Baah). A short peptide that represents amino acids 90-101 of BPI was then synthesized to test if it possessed any LPS binding and antibacterial activities. Results from in vitro lymphocyte culture indicated this peptide was able to inhibit LPS-induced lymphocyte proliferation, suggesting that it may interact with LPS. This LPS binding ability of BPI peptide 90-101 was further supported by the results from HPLC assays which showed the mobility of the peptide shifted in the presence of LPS. Furthermore, the antibacterial spectra of this peptide and cecropin peptide 1-11 were very similar to that of polymyxin B, even though the antibacterial activities of these two peptides were less potent than that of polymyxin B. In addition, the antibacterial activities of these two peptides and polymyxin B were inhibited by free LPS or a high concentration of MgCl2. These results thus suggest that a common structure (Baah) and antibacterial mechanism may be involved in these antibacterial agents.

Animals↗

PubMed1993

Splicing mutations of the p53 gene in human hepatocellular carcinoma.

Point mutations in exons of the tumor suppressor p53 gene occur frequently in many human tumors including hepatocellular carcinoma and are extensively studied. However, intronic point mutations are rare and are totally unknown for hepatocellular carcinoma. By reverse transcription and polymerase chain reaction amplification of p53 RNA from hepatocellular carcinoma tissues of 45 Taiwanese patients, we found amplified complementary DNA fragments of abnormal size in 4 (9%) tumor samples. Sequence analysis of these complementary DNA products revealed aberrant retention of intron 7 in one sample, insertion of 49 base pairs of the 3' end of intron 6 in 2 samples, and deletion of exon 4 in the other sample. Direct sequencing of their genomic DNA revealed relevant point mutations at consensus sequence at either the 5' or 3' splice site of intron 7, 6, 6, and 3, respectively. The splicing mutations produced p53 mutants with truncation of COOH-terminus that are identical to those found in lung cancers. Three of the 4 patients with splicing mutations were younger and had huge tumors. The results suggest a possible role of these p53 mutants in the development of human cancers.

Adolescent↗

PubMed1993

Monoclonal anti-CD44 antibody acts in synergy with anti-CD2 but inhibits anti-CD3 or T cell receptor-mediated signaling in murine T cell hybridomas.

We investigated the effects of anti-murine CD44 monoclonal antibodies on the activation of antigen-specific T cell hybridomas. Anti-murine CD44 antibodies by themselves did not induce the production of IL-2 by antigen-specific T cell hybridomas. However, anti-murine CD44 monoclonal antibodies were able to either inhibit or enhance the production of IL-2, depending on the other monoclonal antibodies used as comitogenic stimuli. When a T cell hybridoma was activated by antigen and antigen-presenting cells or anti-CD3 antibodies, addition of anti-CD44 antibodies inhibited IL-2 production. In contrast, monoclonal anti-CD44 antibodies acted in synergy with anti-human CD2 antibodies in stimulating a murine T cell hybridoma stably transfected with the human CD2 gene to produce IL-2. Therefore, cross-linking of surface CD44 is able to deliver either a positive or a negative signal in murine antigen-specific T cell hybridomas. One of the ligands for CD44 is hyaluronic acid. Hyaluronic acid in vitro significantly increased the activation of murine T cell hybridomas. Hyaluronic acid itself was mitogenic for T cell hybridomas. Therefore, in addition to being an adhesion molecule, CD44 functions as a signal-transducing molecule on murine T cell hybridomas.

Animals↗

PubMed1993

Prognostic factors and impacts of adjuvant therapy in early-stage cervical carcinoma with pelvic node metastases.

Three hundred seventy cases of clinical stage Ib-II cervical carcinoma treated with radical abdominal hysterectomy and bilateral pelvic lymphadenectomy at Chang Gung Memorial Hospital between 1981-1986 were reviewed retrospectively. Of these, 105 patients had pelvic lymph node metastases. Clinicopathological variables including flow cytometric DNA analysis and the use of adjuvant therapy were studied. Recurrence-free survival was significantly worse among patients with positive pelvic nodes by parametrial extension, increasing number of positive nodes, and DNA index greater than 1.3. In patients with positive nodes and negative parametria, the number of positive nodes remained a significant predictor of survival. Utilizing these significant variables, we identified three distinct risk groups. Those patients who had negative parametria, only one positive node, and a DNA index not greater than 1.3 were categorized as the low-risk group. Those who had either positive parametria or more than three positive nodes were categorized as the high-risk group. All the others fell into the intermediate-risk group. Five-year recurrence-free survival rates were 84.6, 71.6, and 42.1%, respectively (P = 0.0006). Applying this risk group classification and the significant risk factors, we may select more appropriate subsets of patients and good stratification for future prospective trials in surgically treated early-stage cervical carcinoma patients with pelvic node metastases.

Antineoplastic Agents↗

PubMed1993

Antitumor agents, 145. Cytotoxic asprellic acids A and C and asprellic acid B. new p-coumaroyl triterpenes, from Ilex asprella.

Three new p-coumaroyl triterpenes, asprellic acids A [1], B [2], and C [3], were isolated from the EtOH extract of dried leaves of Ilex asprella. The structures for 1-3 have been established as 3,27-di-O-trans-p-coumaroyl [1], 3-O-trans-p-coumaroyl-27-O-cis-p-coumaroyl- [2], and 3-O-cis-p-coumaroyl-27-O-trans-p-coumaroyl- [3] 3 beta,27-dihydroxyolean-12-en-28-oic acid, respectively, by spectral and chemical examinations. Asprellic acid A [1] exhibited potent cytotoxicity against the RPMI-7951 cell line with an ED50 value of 0.62 micrograms/ml, while the cytotoxicity of asprellic acid C [3] against RPMI-7951 was marginal (ED50 5.5 micrograms/ml). Compounds 1 and 3 also showed cytotoxicity against KB cells with ED50 values of 3.75 and 2.86 micrograms/ml, respectively. Asprellic acid B [2] did not show cytotoxicity (> 10 micrograms/ml) against KB or RPMI-7951 cell lines.

Adenocarcinoma↗

PubMed1993

A comparative study on commercial samples of phellodendri cortex.

A total of 31 commercial samples of Phellodendri cortex (Rutaceous plant) which originated from PHELLODENDRON AMURENSE Ruprecht, P. CHINENSE Schneid, P. WILSONII Hayata et Kanehira, and P. AMURENSE Rupr. var. SACHALINENSE Fr. Schm., respectively, were collected from the Taiwan and Japan herbal markets. The contents of five quaternary alkaloids (berberine, palmatine, jatrorrhizine, phellodendrine and magnoflorine) in these samples were determined by capillary electrophoresis. It was found that P. WILSONII (4.10 +/- 0.78%) and P. AMURENSE var. SACHALINENSE (4.18 +/- 1.03%) were superior to P. AMURENSE (1.55 +/- 0.72%) and P. CHINENSE (1.54 +/- 0.60%). Berberine was the major alkaloid in almost all samples. In comprised about 80% of the total alkaloids in the first two of the four herbs named above, but only about 40% in the latter two. From the data on the chemical analysis of the herb's constituents, as well as the herb's texture and color, we can postulate the origin and quality of a herb drug.

Journal Article↗

PubMed1993

The thrombolytic effect of lumbrokinase is not as potent as urokinase in a rabbit cerebral embolism model.

The purpose of the present study is to determine whether lumbrokinase has an in vivo thrombolytic effect in a rabbit cerebral embolism model. In our previous studies, we found that lumbrokinase, an extract from Korean earth worms, has a strong in vitro fibrinolytic effect without the presence of plasminogen and significant in vivo thrombolytic effects of lumbrokinase in a rat human-clot-induced cerebral embolism model. We established the cerebral embolism model in rabbits by injecting a piece of human clot into the internal carotid artery via the external carotid artery and confirmed the occlusion with angiography. Twenty one rabbits were divided into three groups and 5cc of saline, urokinase of 50,000 u/ml, and equipotent LK were injected intraarterially for 30 minutes into each group of 7 animals. Ten minutes after the end of infusion, an angiogram was performed to confirm the recanalization. Clot lysis occurred in one, six, and one animals in the saline, urokinase and lumbrokinase treated groups respectively. With regard to its in vitro effect, lumbrokinase is not as potent in vivo. Further investigation should be performed to determine the cause of its weakened in vivo effect and to develop a method to potentiate it.

Animals↗

PubMed1993

Ultrasound imaging aids infraclavicular brachial plexus block.

Infraclavicular approach to the brachial plexus provides adequate anesthesia of the entire arm. Local anesthetics can be deposited over cords and branches of brachial plexus above the formation of musculocutaneous and axillary nerves. The approach can also easily block ulnar segment of medial cord and intercostobrachial nerve, which helps preventing tourniquet pain. However, distance to the plexus is deeper than the other approaches so that current blind method using anatomical landmarks requires anesthesiologists' delicate manipulation and experience. Through ultrasonography, the location of subclavian artery, as an anatomical landmark, can be easily identified. It is then very easy and safe to perform infraclavicular brachial plexus block. Our new method showed 89% (n = 9) successful rate. The time for the block was 4.2 +/- 1.5 min and there was an average of 3.2 +/- 0.6 needle penetrations. Thirty three percent (n = 3) had subclavian artery been punctured without formation of hematoma clinically. No patient had clinical postoperative pneumothorax.

Adult↗

PubMed1993

[Intravenous midazolam for sedation in epidural anesthesia].

30 cases receiving epidural anesthesia for lower extremities and abdominal surgery were selected in this study. Their physical status and average age were ASA I or II and 41 +/- 10.0 years old. Premedication included intramuscular injection of pethidine, atropine and promethazine. Epidural anesthesia was accomplished with 15 ml 2% lidocaine with epinephrine (1:80,000). After the stabilization of vital signs, the patients were put asleep by 0.1 mg/kg of midazolam intravenously. They were then evaluated by the sedative, cardiovascular, respiratory and recovery effects of intravenous midazolam in epidural anesthesia. The results were as follows: The patients receiving IV midazolam averagely fell asleep in 61.6 +/- 20.5 seconds and maintained asleep for 55.4 +/- 12.7 minutes. Pain on injection was not noted in these cases. Cardiovascular parameters revealed midazolam with general depression on systolic pressure (17.4 +/- 7.3%), diastolic pressure (13.4 +/- 8.4%), mean arterial pressure (12.7 +/- 7.0%), heart rate (10.9 +/- 7.2%), stroke volume (13.7 +/- 8.9%) and cardiac output (18.4 +/- 7.0%) respectively. The peak depression reached around 10 minutes after drug administration. Respiratory parameters dropped with SaO2 (1.1 +/- 1.6%) and respiratory rate (9.7 +/- 5.7%) and fell into trough after 5 minutes of drug administration. Although all the above parameters measured were statistically significant, they were of no clinical importance that required further management. No case had delirium, anxiety and vomiting in the recovery period. Conclusively, patients receiving epidural anesthesia with supplement of intravenous midazolam provides a good sedative effect. Clinically, there was less severe untowards reaction either in cardiovascular or respiratory systems. Smooth and stable recovery was also noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

[The mechanism of the pineal gland in inhibiting sexual receptivity of female rats treated with monosodium-L-glutamate: (III). Does it concern with the function of the pituitary gland?].

To elucidate whether pituitary function participates in the effect of the pineal gland on sexual receptivity, monosodium L-glutamate (MSG) was used as a neurotoxin to induce hypogonadal status. Long-Evans rats were divided into four groups: (1) normal control (C), (2) pinealectomized (Px), (3) MSG-treated (MSG) and (4) pinealectomized MSG-treated (Px-MSG). Pinealectomy was performed at six weeks of age. In the first part of the experiment, the sexual receptivity was estimated at the age of 2.5 months by lordosis quotient (LQ). The result indicates that the decline of receptivity by neonatal MSG treatment can be significantly improved by pinealectomy. In the second part of the experiment, the effect of pinealectomy on pituitary function was examined by two tests including (1) post-castrational LH rise and (2) pituitary response to LHRH. Ovariectomy was performed at the age of 2.5 months. Four weeks later three consecutive blood samples were collected at 10 minute intervals for LH radioimmunoassay. Then, three doses of LHRH (100 ng, 250 ng and 500 ng/100 g of body weight) were administered separately at two-week intervals, serum samples were taken before as well as 15 and 60 minutes after LHRH administration. The results showed that there was no significant difference in serum LH levels between Px and control rats after ovariectomy. The LHRH-evoked LH elevation in Px-MSG rats was just the same as that of the MSG rats, although the LH level in MSG rats was lower than in the control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

CD3 zeta dependence of the CD2 pathway of activation in T lymphocytes and natural killer cells.

In T lymphocytes, signal transduction through the CD2 adhesion molecule requires surface expression of the CD3-Ti T-cell receptor (TCR) complex. In contrast, in natural killer (NK) cells, CD2 functions in the absence of a TCR. Because the TCR on T lymphocytes and the CD16 low-affinity IgG Fc receptor (Fc gamma receptor type III) complex on NK cells share a common CD3 zeta subunit, we reasoned that CD3 zeta may be critical for CD2 signaling in T lymphocytes and NK cells. Here we show that transfection of a cDNA encoding a transmembrane form of CD16 into TCR- variants of the Jurkat T-cell line results in CD16 expression in association with endogenous CD3 zeta homodimers and restores CD2 signaling function. To test directly the role of CD3 zeta in CD2 triggering, we then transfected human CD2 into each of two murine T-T hybridomas that express TCRs containing either a full-length CD3 zeta subunit or a truncated CD3 zeta subunit incapable of transducing signals. Despite expression of equivalent surface levels of TCR, CD2-mediated signaling is seen only in the T cells containing wild-type CD3 zeta. These findings show that (i) CD16 on NK cells is functionally equivalent to the TCR on T lymphocytes for coupling CD2 to signaling pathways and (ii) CD2 signal transduction depends upon the CD3 zeta subunit of the TCR complex and, by inference, the CD3 zeta subunit of the CD16 complex.

Animals↗

PubMed1992

Neoadjuvant chemotherapy with cisplatin, vincristine, and bleomycin and radical surgery in early-stage bulky cervical carcinoma.

Neoadjuvant chemotherapy consisting of 2-3 courses of cisplatin, vincristine, and bleomycin was used in the primary treatment of 36 consecutive patients with locally advanced early-stage cervical carcinoma [International Federation of Gynecology and Obstetrics (FIGO) stages Ib or IIa; tumor size, greater than or equal to 4 cm]. The effectiveness of the preoperative chemotherapy was evaluated in the surgical specimens. Among the 33 evaluable patients, the overall clinical response rate was 84.8%, which included a complete response in 8 patients (24.2%) and a partial response in 20 subjects (60.6%). No residual tumor was found in the surgical specimens obtained from 2 complete responders. This therapy induced varying degrees of tumor shrinkage and rendered radical surgery feasible in all evaluable cases despite the initial bulky size of the lesions. No significant difference was observed in the response rate according to age and disease stage. Lymph-node metastases were found after chemotherapy in 18.2% (6/33) of the patients. Grade II and III hematological toxicities occurred in 23.3% of the 90 chemotherapy cycles completed. Nausea and vomiting occurred to a mild to moderate degree in 75 (83.3%) cycles. These preliminary results suggest that the administration of induction chemotherapy involving two to three courses of cisplatin, vincristine, and bleomycin prior to surgery is effective in reducing the tumor volume and in providing better circumstances for surgical removal of the early yet bulky cervical tumors and results in tolerable toxicity. This protocol is now undergoing prospective randomized trials to test its impact on long-term survival.

Adult↗

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

Preliminary results of concurrent radiotherapy and chemotherapy with cis-platinum, vincristine, and bleomycin in bulky, advanced cervical carcinoma: a pilot study.

Twenty-four patients with bulky (greater than 4 cm), advanced (stages IIB-IVA) carcinoma of the uterine cervix were prospectively treated with a concurrent combination of radiotherapy (RT) and chemotherapy (CT). RT consisted of 4400 cGy (22 fractions) to the whole pelvis and a 1400-cGy boost to the parametrium. This was followed by two to three intracavitary brachytherapy courses. CT consisted of one to four course (median, three) of cisplatin (50 mg/m2) on Day 1, vincristine (1 mg/m2) on Day 2, and bleomycin (25 mg/m2) on Days 2-4. CT was started on the first day of external radiation and the scheduled course interval was 21 days. Among the 20 evaluable patients who completed at least one course of chemotherapy and a full course of radiation, 13 (65%) achieved complete response and 5 (25%) had partial response. Fatal complication occurred in 1 patient with stationary disease who died of septic shock due to ruptured pyometra. The other patient with primary stage IVA disease had progressive disease with ascites appearance after two courses of CT and later expired. Transient drug fever occurred in 19 (40.4%) of the 47 bleomycin-containing CT cycles. Grade 2 or 3 hematological toxicities occurred in 16 (30.2%) of a total of 53 CT cycles. Treatment delays of 1 to 7 days occurred in 15 (28.3%) CT cycles. Except for the case of septic shock, all of the other toxicities were generally tolerable and reversible. From this preliminary result we concluded that this particular combination of RT and CT in bulky, advanced cervical carcinoma is effective in enhancing local pelvic tumor control and well tolerated if strict selection of accrued patients is applied. Further investigation to assess its impact on long-term survival is in progress.

Adenocarcinoma↗

PubMed1992

Site-directed mutagenesis of pseudoazurin from Alcaligenes faecalis S-6; Pro80Ala mutant exhibits marked increase in reduction potential.

Pseudoazurin (a blue copper protein or cupredoxin) of a denitrifying bacterium Alcaligenes faecalis S-6 is a direct electron carrier for a Cu-containing nitrite reductase (NIR) of the same organism. Site-directed mutagenesis of the pseudoazurin was carried out using an Escherichia coli expression system. Replacement of Tyr74 by Phe to remove an internal hydrogen bond in the beta-barrel caused a slight decrease in heat stability as well as a requirement for a higher concentration of Cu2+ for production in the E. coli host. Exchange of Ala for Pro80 adjacent to His81, one of the four ligands binding a type I Cu atom, caused a marked increase in reduction potential by 139 mV without change in the optical absorption spectrum. The ability of the pseudoazurin to transfer electrons to NIR was markedly diminished but the apparent Km of NIR for pseudoazurin was not affected by the mutation. X-ray diffraction data collected on the oxidized and reduced forms of the Pro80Ala mutant show that a water molecule occupies the pocket created by the absent side chain. This observation suggests that the increase in reduction potential may be caused due to the increased solvent accessibility to the Cu atom. The electron density difference maps on these structures (at 2.0 A) show that this water moves during the change in oxidation state, and that there are small, but localized, conformational changes greater than 6.5 A from the copper site, as well as movement of both the Cu2+ and the cysteinate sulfur.

Alcaligenes↗

PubMed1992

Human papillomavirus in benign and malignant ovarian and endometrial tissues.

Ovarian and endometrial cancer tissues were examined for the presence of human papillomavirus (HPV) and the results were compared with the findings in normal tissues by polymerase chain reaction. Putative DNA of HPV types 16 and 18 that target DNA sequences from paraffin-embedded tissues were amplified with paired oligonucleotide primers that encode the E6 gene of HPV. The amplified DNA sequences were then detected with Southern blot hybridization analysis. The HPV DNA sequences were detected in both benign (50% ovarian, 70% endometrial) and malignant ovarian (27.2%) and endometrial (37.5%) tissue samples. Interestingly, eight hepatoma samples were also analyzed as tissue controls. The results were negative in seven, but positive in one with repeated tests. The results suggest that the spread of HPV in the upper genital tract may not be uncommon. The explanation of a positive liver tissue study result will have to await further study.

Adenocarcinoma↗