PubMed Health⌕ Search

Biomedical subjects

Y C Ho

Publications and source records attributed to Y C Ho.

16 recordsLinked to original sources
PubMed2001

Continuous cardiac output monitoring system.

A continuous cardiac output monitoring system has been developed in the laboratory to allow the real-time measurement of the cardiac output. This form of continuous cardiac output measurement allows the doctor to view the beat-to-beat cardiac output and can be employed to measure artery constrictions as well. The sensor comprises a laser Doppler velocimeter and an impedance measurement unit. The laser Doppler velocimeter is capable of measuring bi-directional blood flow within the vessel while the impedance measurement unit determines the cross-sectional area of the vessel. In laboratory tests, it was demonstrated on a heart-lung machine that the product of the two parameters measured is proportional to the actual flow volume of up to 6 lmin(-1) with a mean percentage error of 12.4% and a mean square error of 0.09 (using the lmin(-1) scale) were obtained. This is significantly more accurate than the measurement made using the thermodilution cathether.

Cardiac Output↗
PubMed2001

Isolation and characterization of a Vibrio vulnificus mutant deficient in both extracellular metalloprotease and cytolysin.

We isolated a Vibrio vulnificus mutant that was deficient in both metalloprotease and cytolysin by allelic exchange. The virulence of this mutant in mice and its cytotoxicity for HEp-2 cells were comparable to those of the wild-type strain, indicating that neither factor was essential for these properties. The cytolysin, but not the protease, seemed to be important for causing damage in the alimentary tract of the mice.

Animals↗
PubMed2001

Diabetic foot ulcers in the Hong Kong Chinese population: retrospective study.

OBJECTIVE: To assess the predictive power of various parameters on the final outcome of ulcerated diabetic feet among the Hong Kong Chinese population. DESIGN: Retrospective cohort study. SETTING: Regional public hospital, Hong Kong. PATIENTS: Medical records of 340 diabetic patients with foot ulcers (535) who were referred to the Diabetic Foot Clinic between July 1995 and June 2000 were reviewed. MAIN OUTCOME MEASURES: Demographic and clinical data, including assessment of the foot and blood parameters. RESULTS: Increasing age, wound depth, the presence of ischaemia, a low albumin level, and the lack of simultaneous ulceration were determined by stepwise logistic regression analysis to be the most significant independent predictors of an unfavourable outcome. CONCLUSIONS: Major amputation is more likely to occur in elderly patients, with progressive wound depth, and in the presence of ischaemia. A low albumin level was also noted to be an independent predictor of major amputation in the population studied.

Adult↗
PubMed1995

Photoaffinity labeling of retinoic acid-binding proteins.

Retinoid-binding proteins are essential mediators of vitamin A function in vertebrate organisms. They solubilize and stabilize retinoids, and they direct the intercellular and intracellular trafficking, transport, and metabolic function of vitamin A compounds in vision and in growth and development. Although many soluble retinoid-binding proteins and receptors have been purified and extensively characterized, relatively few membrane-associated enzymes and other proteins that interact with retinoids have been isolated and studied, due primarily to their inherent instabilities during purification. In an effort to identify and purify previously uncharacterized retinoid-binding proteins, it is shown that radioactively labeled all-trans-retinoic acid can be used as a photoaffinity labeling reagent to specifically tag two known retinoic acid-binding proteins, cellular retinoic acid-binding protein and albumin, in complex mixtures of cytosolic proteins. Additionally, a number of other soluble and membrane-associated proteins that bind all-trans-[11,12-3H]retinoic acid with high specificity are labeled utilizing the same photoaffinity techniques. Most of these labeled proteins have molecular weights that do not correspond to any known retinoid-binding proteins. Thus, photoaffinity labeling with all-trans-retinoic acid and related photoactivatable retinoids is a method that should prove extremely useful in the identification and purification of novel soluble and membrane-associated retinoid-binding proteins from ocular and nonocular tissues.

Affinity Labels↗
PubMed1995

Expression of the erythrocyte antigen Henshaw (He; MNS6): serological and immunochemical studies.

Production of murine monoclonal antibodies to the low prevalence MNS antigen Henshaw (He; MNS6) has enabled more detailed study of this antigen. Using these directly hemagglutinating anti-He, red blood cells (RBCs) from 1695 people of African origin were screened in the USA and England. The prevalence of He+ samples among these donors was 2.1%. In Natal, blood samples from 1218 black donors were screened with rabbit anti-He. The prevalence of He+ donors in this population was 7.0%. Immunoblotting confirmed that the He antigen is carried on an erythrocyte membrane component with a molecular mass that is indistinguishable from glycophorin B. Hemagglutination and immunoblotting demonstrated that ten of 56 He+ samples tested more extensively had a reduced expression of the He antigen. The majority of He+ RBCs were S+; those He+ RBC samples that were S-s+ more frequently had a weakened expression of He.

Antibodies, Monoclonal↗
PubMed1994

Electroejaculation for the treatment of idiopathic anejaculation: a case report.

Electroejaculation to produce semen from anejaculated males has been employed successfully in conjunction with intrauterine insemination (IUI), in vitro fertilization/embryo transfer, and gamete intrafallopian transfer. We herein report the use of IUI to achieve pregnancy following electroejaculation in a patient with primary idiopathic anejaculation. This 30-year-old patient had a history of anejaculation that was noted after marriage, but had normal sexual potency and occasional nocturnal emission. Electroejaculation was successfully used to obtain semen. The highly motile sperm was recovered from swim up procedure and used for IUI. The 25-year-old wife was given clomiphene citrate and Pergonal for ovulation induction. A triplet pregnancy was achieved. At 26 weeks of gestation, the first triplet was delivered after spontaneous rupture of membrane. We tried to delay delivery of this retained twin pregnancy. Thirty-two days later, the remaining two fetuses were delivered weighing 1100 gm and 900 gm. Ninety-three days after delivery, these two babies were discharged, putting on weight to 3564 gm and 3264 gm. This case represents the first success of using electroejaculation to achieve pregnancy from anejaculated patient in Taiwan.

Adult↗
PubMed1990

Platelet-associated immunoproteins (PAIg): specificity of measurement.

Platelet-associated Ig (PAIg) is raised in patients with idiopathic thrombocytopenic purpura. However, it is also raised in conditions not traditionally considered to be immune mediated. The latter finding suggests that raised PAIg may be an epiphenomenon of thrombocytopenia. The assays currently available do not distinguish between PAIg present due to a specific Fab binding or present due to non-specific binding of Ig via Fc or complement receptors. In this paper we show that by prior incubation with normal rabbit serum, an assay for PAIg can be made specific for Fab binding.

Blood Platelets↗
PubMed1989

Leucocyte count and neutrophil percentage in appendicectomy for suspected appendicitis.

The total leucocyte count (TLC) and neutrophil percentage (NP) were studied prospectively in 1032 patients who underwent appendicectomy for suspected acute appendicitis. On histopathological study of the resected appendices, 97 patients had normal appendices, and 935 patients had acutely inflamed, gangrenous or perforated appendicitis. Statistically more patients with appendicitis had either raised TLC or raised NP compared with patients with normal appendices (P less than 0.001), and also compared with 357 patients who were admitted with right lower quadrant abdominal pain but were not subjected to operation (P less than 0.001). The sensitivity and specificity of raised TLC in diagnosing appendicitis for patients who underwent appendicectomy were 81.4% and 77.3%, respectively. Sensitivity increased when either raised TLC or raised NP were used, but specificity decreased. In contrast, sensitivity decreased when both raised TLC and raised NP were used together, but specificity increased. Raised TLC, preferably combined with raised NP, is a useful diagnostic aid in acute appendicitis. The TLC and NP, however, should only be interpreted in the light of physical findings in patients with suspected appendicitis because these blood tests have false positive and false negative results.

Acute Disease↗
PubMed1988

Human beta-glucuronidase. Measurement of its activity in gallbladder bile devoid of intrinsic interference.

Our purpose is to develop a standard method for preparing the bile for beta-glucuronidase determination by removal of bile acids and conjugated bilirubin which interfere with its activity. The bile acids and conjugated bilirubin in their purified solutions and in the diluted gallbladder biles could be extracted completely with cholestyramine in powder form or tetrahexylammonium chloride (THAC) in chloroform or ethyl acetate. The enzyme was, however, partially precipitated with cholestyramine and denatured by chloroform but not by ethyl acetate. A standard procedure, therefore, includes extraction of the diluted gallbladder bile with THAC in ethyl acetate, followed by determination of the maximal velocity (Vmax) of the enzyme by a kinetic method employing phenolphthalein glucuronide as the substrate. The average Vmax of beta-glucuronidase in the 20 normal gallbladder biles was 165 +/- 86 nmol/min/ml (mean +/- SD), a 23.5-fold increase over the activity before extraction. The measured activity represented the true activity of the enzyme in the bile for recovery of activity of the enzyme added to the bile was practically complete.

Acetates↗
PubMed1985

Differential quantitation of urinary beta-glucuronidase of human and bacterial origins.

A method for the differential quantitation of urinary beta-glucuronidases of human and bacterial origins is presented. The activity of human enzyme at pH 6.5 was 36 per cent of its peak activity at pH 5.0 while the activity of bacterial enzyme at pH 5.0 was 20 per cent of its peak activity at pH 6.5. By simultaneous determination of the activity in a mixture of the enzymes of these two sources at both pH 5.0 and 6.5 and by simple mathematic proportion the individual activity of human and bacterial enzymes could be determined separately. This provides a quick method for differential diagnosis between bacterial and non-bacterial disease of the urinary system.

Escherichia coli↗
PubMed1985

Human hepatic beta-glucuronidase: an enzyme kinetic study.

beta-Glucuronidase (EC 3.2.1.31) was purified from human liver and its activity was determined by enzyme kinetic method employing phenolphthalein glucuronic acid (PGA) and conjugated bilirubin, primarily bilirubin diglucuronide purified from human bile, as substrates in the absence or presence of D-glucaro-1,4-lactone. The enzyme was capable of acting on both PGA and conjugated bilirubin with Michaelis constants of 0.435 mmol/l at 56 degrees C and 1.02 mmol/l at 37 degrees C, respectively. Both reactions were beta-glucuronidase-specific because both were inhibited by D-glucaro-1,4-lactone in a competitive fashion. Conjugated bilirubin acted as a noncompetitive inhibitor of the enzyme for PGA in a two-substrate system. The study indicates that these two substrates bind at different catalytic sites of the enzyme and, on molar base, conjugated bilirubin had higher affinity for the enzyme and less degree of inhibition by D-glucaro-1,4-lactone than PGA. Whether such catalytic sites are also common for other beta-D-glucuronid ethers and esters remains to be proven.

Bilirubin↗