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Biomedical subjects

M C Chang

Publications and source records attributed to M C Chang.

At least 163 records · Page 9Linked to original sources
PubMed1994

Gastric tonometry supplements information provided by systemic indicators of oxygen transport.

HYPOTHESIS: Assessment of splanchnic perfusion by gastric intramucosal pH (pHi) adds to the information provided by systemic indicators of oxygen transport. SETTING: University Hospital level I trauma center. DESIGN: Prospective study in 20 critically ill trauma patients comparing pHi with base deficit, lactate, oxygen delivery, and oxygen consumption (indexed to body surface area), mixed venous oxygen saturation (Svo2), oxygen utilization coefficient, and arterial pH. All measurements were obtained at admission, 1, 2, 4, 8, 16, and 24 hours, or at death. MAIN OUTCOME MEASURES: Correlation of pHi with the measured systemic variables, prediction of organ dysfunction, development of multiple organ dysfunction syndrome, and mortality. RESULTS: There was a poor correlation between pHi and the systemic hemodynamic and oxygen transport variables. Patients with a low pHi (< 7.32) on admission who did not correct within the initial 24 hours had a higher mortality (50% vs. 0.0%, p = 0.03) and incidence of organ dysfunction (2.6 organs/patient vs. 0.62 organs/patient, p = 0.02) than those who did. Using logistic regression analysis, only pHi, base deficit, and Svo2 were significantly associated with mortality during the study period. At 24 hours, only pHi was different between patients who developed multiple organ dysfunction syndrome and those who did not. There was a threshold value for pHi (7.10) which identified those patients who would go on to develop multiple organ dysfunction syndrome. CONCLUSIONS: Uncorrected splanchnic malperfusion is associated with a higher incidence of organ dysfunction and mortality. Gastric tonometry supplements information provided by systemic indicators of oxygen transport during resuscitation of critically ill trauma patients.

Acid-Base Equilibrium↗
PubMed1994

Sonographic detection of inferior vermian agenesis in Dandy-Walker malformations: prognostic implications.

PURPOSE: To compare the prognoses for fetuses with sonographically detected inferior vermian agenesis (IVA) or complete vermian agenesis (CVA). MATERIALS AND METHODS: The sonograms of 65 fetuses with Dandy-Walker malformations were retrospectively reviewed. Fetuses were divided into two groups--those with IVA and those with CVA. RESULTS: Of the 65 fetuses, 37 had IVA; 28, CVA. Thirteen (20%) of the 65-nine (24%) of the 37 with IVA and four (14%) of the 28 with CVA--lived for longer than 1 year. Chromosomal abnormalities were found in 23 (45%) of the 51 fetuses tested for karyotypic abnormalities or clinically thought to have Down syndrome. Seventeen (53%) of the 32 with IVA and six (32%) of the 19 with CVA that were tested for karyotypic abnormalities or clinically thought to have Down syndrome had chromosomal abnormalities (P = .07). Associated morphologic abnormalities were prenatally detected in 49 (75%) of the 65-in 28 (76%) of the 37 with IVA and in 21 (75%) of the 28 with CVA. CONCLUSION: The overall guarded prognosis is similar for fetuses with Dandy-Walker malformations for whom IVA or CVA has been sonographically diagnosed. Fetuses with IVA have a higher prevalence of karyotypic abnormalities.

Abnormalities, Multiple↗
PubMed1994

Purification and characterization of L-aminoacylase from Alcaligenes denitrificans DA181.

The L-aminoacylase produced intracellularly by Alcaligenes denitrificans DA181 was purified to homogeneity. This enzyme had an apparent molecular weight of 80,000, and was composed of two subunits of identical molecular weight. Its isoelectric point was pH 5.1. The optimal reaction temperature and pH were 65 degrees C and 8.0, respectively. This enzyme showed specificity toward N-acetyl-derivative of hydrophobic L-amino acids with N-acetyl-L-valine as the favored substrate, followed by N-acetyl-L-alanine.

Alcaligenes↗
PubMed1994

A multistate model of fecundability and sterility.

This paper develops a multistate hazards model for estimating fecundability and sterility from data on waiting times to conception. Important features of the model include separate sterile and nonsterile states, a distinction between preexisting sterility and sterility that begins after initiation of exposure, and log-normally distributed fecundability among nonsterile couples. Application of the model to data on first birth intervals from Taiwan, Sri Lanka, and the Amish shows that heterogeneity in fecundability is statistically significant at most ages, but that preexisting sterility and new sterility are unimportant before age 40. These results suggest that sterility may not be an important determinant of natural fertility until later reproductive ages.

Adolescent↗
PubMed1994

Allen score in clinical diagnosis of intracranial hemorrhage.

BACKGROUND: Allen score is a validated weighted linear score for clinical distinction between hemorrhagic and ischemic stroke. As the prevalence of hemorrhagic stroke differs between Caucasian and Chinese populations, and the predictive value of any diagnostic score depends greatly on the prevalence of disease being considered, we tried to verify prospectively this score among the Chinese living in Taiwan. METHODS: From 1 April to 31 August 1993, all patients with acute stroke syndrome, who visited the emergency room at Veterans General Hospital-Taichung, were studied prospectively. Clinical features were recorded thoroughly to calculate the Allen score. The diagnosis was all confirmed by computed tomography (CT) of the head. RESULTS: Totally 255 stroke cases were identified. The types of the stroke were cerebral infarction in 186 subjects (73%), cerebral hemorrhage in 64 subjects (25%), and subarachnoid hemorrhage in 5 subjects (2%). Seventy-five cases were excluded because of the lack of clinical details for calculation. Thus, 180 patients were included. When a cut-off of 4 or 24 was taken into account, the sensitivity of Allen score for diagnosing a hemorrhage was 67%, specificity 100%, accuracy 93%, positive predictive value 100%, and negative predictive value 91%. CONCLUSIONS: Although Allen score can be used for epidemiological studies of incidence and outcome in stroke as well as for a first bedside screening to decide the priority of patients for CT, it is not safe enough as a guide for anticoagulant or thrombolytic therapy. Its validity should be verified before use in a given population other than the Caucasian.

Cerebral Hemorrhage↗
PubMed1994

A case of intrathoracic extramedullary hematopoiesis with massive pleural effusion: successful pleurodesis with intrapleural minocycline.

Extramedullary hematopoiesis is a compensatory process for some hematologic diseases, such as spherocytosis, myelofibrosis and thalassemia. We report a 34-year-old man with beta-thalassemia intermedia who developed intrathoracic extramedullary hematopoiesis with recurrent pleural effusion. Diagnosis of extramedullary hematopoiesis of the pleura and soft tissue was established after thoracoscopic biopsy. Subsequently, the pleural effusion was controlled with intrapleural minocycline instillation. To our knowledge, this is the first case of extramedullary hematopoiesis described in the parietal pleura associated with massive pleural effusion and successfully treated with minocycline.

Adult↗
PubMed1994

[The correlation between cytology and histopathology of primary adenocarcinoma of the uterine cervix].

Cytodiagnosis is a simple, non-invasive and economical screening method for uterine cervical malignancy. Adenocarcinoma as a primary tumor of uterine cervix, although relatively rare, is increasing recently. The first part of the study consisted of 113 patients, seen during a 10-year period, with adenocarcinoma of the uterine cervix proven by tissue diagnosis with prior and/or coincident Papanicolaou smears available in our hospital. Their cytology were as follows: positive/suspicious for adenocarcinoma in 72 cases (63.7%) and incorrect diagnosis for adenocarcinoma in 41 cases (36.3%). These included epidermoid carcinoma, 21 cases (18.6%); atypia, 8 cases (7.1%); negative smears, 8 cases (7.1%); inadequate specimens, 3 cases (2.7%) and radiation effect, 1 case (0.8%). The second part of the study is concerned with the 82 cases whose smear diagnosis was adenocarcinoma in the same period. The results of their tissue diagnosis and accuracy were as follows: adenocarcinoma in 62 cases (75.6%); epidermoid carcinoma in 9 and epidermoid carcinoma in situ in 3 cases totalling 12 cases (14.6%); and false positive in 8 cases (9.8%). The cytomorphology and its correlation to underdiagnosis and overdiagnosis is discussed. Our data revealed that cervicovaginal smears served as a routine for the screening of primary adenocarcinoma of the uterine cervix and for follow-up and detection of recurrence. In order to increase the accuracy, screening cytotechnicians and cytopathologists should acquaint themselves with the morphology of cervical adenocarcinoma by comparing cervicovaginal smear with histopathology.

Adenocarcinoma↗
PubMed1994

A retrospective study of DNA ploidy of transitional cell carcinoma of urinary bladder using flow cytometry.

Transitional cell carcinoma is the most common malignancy of urothelial origin in urinary bladder. Its aggressive potential cannot be reliably predicted from the histologic appearance alone. Recently, there has been extensive studies of DNA ploidy using flow cytometry in prospective analysis of bladder tumors with fresh tissue. Techniques for the preparation of paraffin embedded tissue have been developed and successfully applied in retrospective evaluation of bladder tumors. These studies had demonstrated the correlation between histological grading and DNA ploidy, and between clinical staging and DNA ploidy. Our retrospective study showed that the cytometric method is superior to histologic grading in the predictability of patient's survival, especially in the low grade (grades 1 and 2) group. In the preparation of paraffin embedded tissue, the high background debris and wide range of coefficients of variation had some interference in the interpretation for the histogram of FCM (only 80% of the cases studied are interpretable). This interference might be due to the variation of conditions of tissue processing and fixation. The evaluation of S phase fraction and G2/M fraction is also difficult to perform because of the same problem. There was an encouraging result in the evaluation of DNA ploidy using flow cytometry with paraffin embedded tissue, although a relatively small number of patients were included in this study. The value of this technique application in clinical evaluation of the prognosticity was obvious.

Adult↗
PubMed1993

Antiplatelet protease, kistomin, selectively cleaves human platelet glycoprotein Ib.

Kistomin, a metalloprotease purified from venom of Calloselasma rhodostoma, dose- and time-dependently prolonged the latent period of aggregation and inhibited ATP secretion of human washed platelets stimulated by thrombin. It inhibited aggregation induced by low concentrations of thrombin (< or = 0.2 U/ml) whereas it had only slight effect on aggregation induced by high concentrations of thrombin (> or = 0.5 U/ml). Meanwhile it also inhibited ristocetin-induced platelet aggregation in a dose- and time-dependent manner. It significantly inhibited cytosolic calcium rise of Quin 2--loaded platelets, completely blocked thromboxane B2 formation, and blocked [3H]inositol phosphates formation of [3H]myoinositol loaded platelets stimulated by 0.1 U/ml of thrombin. Kistomin inhibited significantly thromboxane but not [3H]inositol phosphates formation of platelets stimulated by a high concentration of thrombin (1 U/ml). Incubation of platelets with kistomin resulted in a selective cleavage of platelet membrane glycoprotein Ib as revealed by SDS/PAGE stained by periodic acid/Schiff reagent. These results suggested that thrombin activates platelets at least through two receptors/or effectors-mediated events. In addition to glycoprotein Ib, other surface membrane component(s) (e.g., the seven transmembrane domain thrombin receptor) may also be important in regulating the biochemical events of human platelets in response to thrombin. However, the extent and rate of platelet aggregation stimulated by low concentrations of thrombin ( < or = 0.2 U/ml) are closely related with the intactness of glycoprotein Ib.

Ancrod↗
PubMed1993

Evidence for a cannabinoid receptor in sea urchin sperm and its role in blockade of the acrosome reaction.

Delta-9-tetrahydrocannabinol ((-)delta 9 THC), the primary psychoactive cannabinoid in marihuana, reduces the fertilizing capacity of sea urchin sperm by blocking the acrosome reaction that normally is stimulated by a specific ligand in the egg's jelly coat. The bicyclic synthetic cannabinoid [3H]CP-55,940 has been used as a ligand to demonstrate the presence of a cannabinoid receptor in mammalian brain. We now report that [3H]CP-55,940 binds to live sea urchin (Strongylocentrotus purpuratus) sperm in a concentration, sperm density, and time-dependent manner. Specific binding of [3H]CP-55,940 to sperm, defined as total binding displaced by (-)delta 9THC, was saturable: KD 5.16 +/- 1.02 nM; Hill coefficient 0.98 +/- 0.004. This suggests a single class of receptor sites and the absence of significant cooperative interactions. Sea urchin sperm contain 712 +/- 122 cannabinoid receptors per cell. Binding of [3H]CP-55,940 to sperm was reduced in a dose-dependent manner by increasing concentrations of CP-55,940, (-)delta 9THC, and (+)delta 9THC. The rank order of potency to inhibit binding of [3H]CP-55,940 to sperm and to block the egg jelly stimulated acrosome reaction was: CP-55,940 > (-)delta 9THC > (+)delta 9THC. These findings show that sea urchin sperm contain a stereospecific cannabinoid receptor that may play a role in inhibition of the acrosome reaction. The radioligand binding data obtained with live sea urchin sperm are remarkably similar to those previously published by other investigators using [3H]CP-55,940 on mammalian brain and nonneural tissues. The cannabinoid binding properties of this receptor appear to have been highly conserved during evolution. We postulate that the cannabinoid receptor may modulate cellular responses to stimulation.

Acrosome↗
PubMed1993

Cloning and nucleotide sequence of an extracellular alpha-amylase gene from Aeromonas hydrophila MCC-1.

A gene encoding the extracellular alpha-amylase of Aeromonas hydrophila MCC-1 was cloned and expressed using its own promoter on the recombinant plasmid pCA101. Subcellular fractionation of Escherichia coli JA221 carrying pCA101 revealed that approximately 60% of the amylase activity was localized in the periplasmic space. The extracellular amylase was purified to homogeneity, identified as an alpha-type and its amino-terminal sequence was determined. Nucleotide sequence analysis predicted a 443 amino acid ORF and 24 amino acids at the amino terminus of the sequence that are not found in the secreted protein. This 24 amino acid sequence has many of the characteristics common to known signal peptides. The predicted amino acid sequence has considerable similarity with mammalian, invertebrate and Streptomycete alpha-amylases. Most of the amino acid residues that are involved in catalytic activity, substrate binding and calcium binding in several alpha-amylases were also present in A. hydrophila alpha-amylase at the corresponding positions.

Aeromonas hydrophila↗
PubMed1993

[Intraoperative cytology: the use of Liu's stain for immediate diagnosis].

We prospectively studied 305 fresh specimens submitted for intraoperative frozen section diagnosis. Three types of cytologic preparations, namely touch imprint, smearing, and crush method, were performed to obtain adequate material. Liu's stain, which takes only two minutes and is one of the rapid staining methods of the Romanowsky series, was used for immediate interpretation. The accuracy of diagnosis was measured by comparison with final histological diagnosis. Sensitivity and specificity of intraoperative cytology were 94.9% and 95.6% respectively. The false-positive rate, false-negative rate, and suspicious rate were 0.3%, 1.3%, and 1.6%. In combination of intraoperative cytology and frozen section, sensitivity and specificity became 96% and 96.3% respectively. The cytomorphology of breast, thyroid, lymph node, and ovary is briefly described. Most cases of cytological diagnostic error are found in sarcomas and ovarian tumors. We conclude that Liu's stain is a simple, rapid, and reliable staining method in intraoperative cytological diagnosis. It is apparent that intraoperative cytology is able to provide a useful adjunct to the frozen-section diagnosis and an excellent teaching file for cytopathology.

Breast↗
PubMed1993

[The immediate interpretation for fine-needle aspiration cytology].

From December 1990 to November 1992, 2005 cases of immediate interpretation for fine-needle aspiration (FNA) cytology were performed, of which 727 cases were confirmed by surgical pathology. A mobile cytologic laboratory (a cart loaded with a dual viewing microscope, Liu's staining solutions, hair dryer, and slides) can be moved to the Out-patient Department, wards and Computed Tomography room, where clinicians perform aspiration and pathologists read smears. Immediate verbal diagnoses are documented to patients' charts and listed in cytopathologic files. Immediate interpretation in this entire series yielded a sensitivity 92.5%; specificity, 98.1%; false-positive rate, 1.1%; false-negative rate, 3.2%; positive predictive value (PV), 97.3%; negative PV, 94.7% and efficiency, 95.7%. The cause of false-negative results in the 23 cases probably came from the hesitation in making an immediate diagnosis. Most of these cases were malignant lymphoma or breast carcinoma. The roles of immediate cytodiagnosis are (1) to decrease the inadequate rate of FNA specimens; (2) to render preliminary diagnosis for clinicians to make decisions; (3) to provide on-site teaching material for both clinicians and pathology residents to better understand clinicopathological correlations; (4) to act as the initial diagnostic procedure in the evaluation of a superficial palpable mass. This study shows that immediate interpretation for FNA cytology is a simple, rapid, accurate and noninvasive diagnostic procedure that can be routinely used for superficial palpable masses.

Biopsy, Needle↗
PubMed1993

Base deficit as a guide to injury severity and volume resuscitation.

Base deficit is an expeditious and sensitive measure of both the degree and duration of inadequate perfusion, and has utility in the clinical evaluation and management of victims of trauma. It is rapid, accurate, and widely available, and as such may be very useful in the initial evaluation of these patients; it may also be used to help guide and assess the adequacy of volume resuscitation. It has in addition both clinical value and research potential in predicting outcome in these patients, and may be a useful tool to both the clinician and the researcher.

Acidosis↗
PubMed1993

Primary malignant lymphoma of the breast: report of two cases with literature review.

We report two cases of malignant lymphoma of the breast. Extensive investigation on both, demonstrated only a neoplastic lesion confined within the breast. One was managed by local excision, systemic chemotherapy and adjuvant radiotherapy; the other was managed by a modified radical mastectomy, adjuvant radiotherapy and therapeutic chemotherapy. Both of them achieved complete remission 3 years and 1.5 years respectively after management.

Adult↗
PubMed1992

A novel alpha-type fibrinogenase from Agkistrodon rhodostoma snake venom.

By means of CM-Sephadex C-50 column chromatography, gel-filtration on sephadex G-75 and Sephacryl S-200 columns, a purified fibrinogenase, kistomin, was obtained from venom of Agkistrodon rhodostoma. It was a single peptide-chain with a molecular mass of about 21,800 Da containing about 202 amino-acid residues as revealed by amino acid analysis. Kistomin preferentially cleaved A alpha- and subsequently the gamma-chain of fibrinogen, leaving the B beta-chain unaffected. Its fibrinogenolytic activity was estimated to be 36.6 +/- 4.5 mg/min per mg protein and was inhibited by the pretreatment of EDTA, suggesting that it is a metalloproteinase. Its fibrinogenolytic activity in platelet-poor plasma is much less potent as compared to that in purified fibrinogen solution. It inhibited ristocetin-induced aggregation of human platelets in a dose-dependent manner in the presence of von Willebrand factor.

Amino Acids↗
PubMed1992

Cloning and expression in Escherichia coli of the gene encoding an extracellular deoxyribonuclease (DNase) from Aeromonas hydrophila.

The gene encoding an extracellular DNase from Aeromonas hydrophila CHC-1 has been cloned and sequenced. Following expression of the dns in Escherichia coli, it was revealed that some of the cloned enzyme was present in the cell-free extracellular supernatant fluid, and there was no cell lysis and concurrent release of cytoplasmic or periplasmic proteins. Therefore, results suggest that E. coli cells were capable of secreting the DNase extracellularly, albeit very inefficiently. The dns is transcribed from its own promoter in E. coli, and expressed as a 25-kDa product, as determined by sodium dodecyl sulfate-polyacrylamide-gel electrophoresis of the culture supernatant preparations followed by a DNA-hydrolysis assay. Nucleotide sequence analysis predicted a single open reading frame of 690 bp encoding a 230-amino acid (aa) polypeptide, with a potential 20-aa signal peptide located at the N terminus of the predicted protein. The deduced aa sequence of the entire protein is highly homologous with that of the DNase of Vibrio cholerae.

Aeromonas hydrophila↗