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Biomedical subjects

K F Cheng

Publications and source records attributed to K F Cheng.

35 records · Page 2Linked to original sources
PubMed1995

Performance of older adults with and without cerebrovascular accident on the test of visual-perceptual skills.

OBJECTIVES: The purposes of this study were to (a) investigate whether older subjects with brain damage score lower on the Test of Visual-Perceptual Skills (TVPS) than control subjects without brain damage matched for age and education, (b) determine the demographic effects on test performance in both groups, and (c) determine the capacity of TVPS in identifying visual-perceptual deficits in adults with brain damage. METHOD: The study sample consisted of 22 subjects with cerebrovascular accident (CVA) and 155 subjects who were neurologically intact (control group). The TVPS was administered individually to each subject. Raw scores (total response time and accuracy) were analyzed to generate descriptive statistics. Other statistical analysis included analysis of variance, analysis of covariance, discriminant analysis, and Pearson product-moment correlations. RESULTS: There were significant between-group differences on all TVPS measures, with control subjects performing better than subjects with CVA. Age was shown to affect performance on most subtests of the TVPS in the control group. Education had significant influence over each measure, whereas gender differences were significant only in two subtests. No demographic effects were found in the group with CVA. The total TVPS accuracy score was the most powerful discriminator between the two groups, correctly classifying 74.4% of the subjects. Finally, the total accuracy score inversely correlated with total time score. CONCLUSION: The TVPS may be useful in screening for visual-perceptual impairments in adults with CVA. Age, gender, and educational level have no significant impact on the magnitude of visual-perceptual dysfunctions.

Age Factors↗
PubMed1995

Primary culture of mouse myoblasts.

The literature has revealed variations in the protocols for myoblast cultures, and little information is available on myoblast and fibroblast proliferation. Therefore, the purposes of this study were to establish a prudent protocol for myoblast cultures by comparing a variety of culturing procedures used in previous research and to quantitate myoblast proliferation and fusion under different culture conditions. In addition, the growth status of myoblasts and fibroblasts was investigated. Results indicate that the requirements for an ideal myoblast culture should include a combined enzyme of 0.25% trypsin and 0.2% collagenase type IV (1:1), a preplating time of approximately 15-20 minutes, and a seeding density at 1 x 10(5) cells/ml. Furthermore, the mouse sample should be those of newborns. A better proliferative capacity of myoblasts was noted in an incubator of 10% CO2, coupled with Dulbecco's MEM plus 15% fetal calf serum. The doubling times of myoblasts were shorter than those of fibroblasts, and myoblast number reached its highest at 4 and 5 days. The findings of this study are valuable in understanding the growth status of myoblasts and fibroblasts in primary cultures. Moreover, the establishment of requirements for a good growth of myoblast cultures will facilitate myoblast transfer therapy.

Animals↗
PubMed1995

A study of pinch strength in normal Taiwanese adults.

The purpose of this study was to describe norms of pinch strength for normal Taiwanese adults and to investigate the effects of age, gender, height, weight, and digit length on pinch strength. Three types of pinch (i.e. tip, key, and palmar pinch) were measured for a sample of 356 adults aged 20 to 88 years from a major metropolitan city located in southern Taiwan. A newly calibrated B&L pinch gauge was used for strength measurements with a standardized position during testing. The dominant hand was tested first, followed by the nondominant hand. The average of two trials for each pinch strength test was used as the subject's test scores. The results indicated that in the male group, pinch strength remained relatively stable up to 50 to 59 years old before a decline began, whereas pinch strength peaked with the 40- to 59-year-old group for female subjects. Males were stronger than females on all prehension patterns. Pinch strength of the right hand was significantly affected by such variables as the lengths of thumb and index finger and height, along with weight. With regard to the left hand, only height and weight had significant impact on pinch strength. Finally, there was an overall 13% pinch strength difference between the dominant and nondominant hands for the total sample. These findings provide therapists with objective data concerning the pinch strength of the Taiwanese adult's hand for clinical use.

Adult↗
PubMed1994

Mixed estrogenic and anti-estrogenic activities of yuehchukene--a bis-indole alkaloid.

Anti-estrogenic effects of yuehchukene were observed in rat uterotrophic, mice vaginal smear and MCF-7 cell growth assays. Whereas yuehchukene per se was estrogenic in these bioassay models, the co-administration of yuehchukene and an optimal dose of 3,17 beta-estradiol (estradiol) could attenuate the maximum estrogenic response due to estradiol alone. The anti-estrogenic effect of yuehchukene in rat uterine hypertrophy was corroborated by a parallel attenuation of ornithine decarboxylase activity in these tissues. Yuehchukene binds to rat, mice and MCF-7 cell estrogen receptors with a relative binding affinity of 1/150 to 1/300. This binding affinity was positively related to estrogenicity as determined by uterotrophic assay and MCF-7 cell growth. However, this estrogenic effect did not correlate with the degree of competitive receptor binding by a weaker agonist. Indole-3-carbinol and methylbutadienylindole could induce ethoxyresorufin O-deethylase and estradiol-2-hydroxylase in rat liver and MCF-7 cells. It is postulated that the 'free' indole moiety of yuehchukene could possess similar induction activity. Thus yuehchukene may have a dual pharmacological function. While the intact molecule is a weak estrogen, the 'free' indole moiety in yuehchukene may induce an enhancement of estradiol-2-hydroxylase, thus terminating the biological activity of the endogenous estrogen pool. There is obvious benefit in attenuating the estrogen level in post-menopausal breast cancer patients without going directly to the use of tamoxifen or aromatase inhibitor. Yuehchukene may serve this purpose. In this context, the pharmacological evaluation of a hydroxylated yuehchukene analogue and the anti-estrogenic effect of methylbutadienylindole acid-condensation products are now being studied in earnest.

Alkaloids↗
PubMed1994

Response to supplementary vaccination with recombinant or plasma hepatitis B vaccine in healthy non-responding children.

Fifty-three children who failed to respond to four doses of plasma hepatitis B (HB) vaccine (anti-HBs titre < 10 IU l-1) were divided into two groups and received revaccination with either three doses of recombinant HB vaccine (10 micrograms/dose, by 0, 1, 6 month schedule; group A) or two additional doses of plasma HB vaccine (5 micrograms/dose, by 0, 1 month schedule; group B) respectively. Thirty-two vaccinees in group A had a response rate (with anti-HBs > 10 IU l-1) of 53.1% (17/32), 87.5% (28/32), and 100% (32/32) after first, second and third doses of the vaccine respectively. Twenty-one vaccinees in group B had a response rate of 61.9% (13/21) after two additional doses of plasma vaccine. High anti-HBs titres (> 1000 IU l-1) were noted in 50% of the vaccinees in group A after three doses of vaccine. Comparing anti-HBs response between group A and group B after two additional doses of HB vaccine, group A had a higher anti-HBs titre (geometric mean titre 104.7 IU l-1 versus 75.9 IU l-1) along with a better seroconversion rate (87.5 versus 61.9%). However, the differences in vaccine dose between the two groups may also be a contributory factor. Our findings indicate that three doses of recombinant HB vaccine were invariably effective in eliciting a good immune response in previous non-responders to the four doses of plasma HB vaccine. Therefore, it is speculated that these young vaccinees who did not respond to four doses of plasma HB vaccine may not be real non-responders, but hyporesponders.

Child↗
PubMed1994

Grip strength in different positions of elbow and shoulder.

This study investigated the effect of shoulder position on grip strength in 80 men and 80 women. A Jamar dynamometer was used to measure the grip strength in the four testing positions. The four hand strength tests consisted of three positions in which the elbow was maintained in full extension combined with varying degrees of shoulder flexion (ie, 0 degrees, 90 degrees, and 180 degrees) and of one position in which the elbow was flexed at 90 degrees with the shoulder in 0 degrees of flexion. Only the dominant hand was tested. The highest mean grip strength measurement was recorded when the shoulder was positioned at 180 degrees of flexion with elbow in full extension; whereas the position of 90 degrees elbow flexion with shoulder in 0 degrees of flexion had the lowest grip strength score. In addition, the grip strength measured with the elbow in extension, regardless of shoulder position (ie, 0 degrees, 90 degrees, and 180 degrees of flexion), was significantly higher than when the elbow was flexed at 90 degrees with the shoulder positioned at 0 degrees of flexion. Finally, grip strength differed significantly for both sexes and for each age group. The grip values of the standardized 90 degrees elbow flexed position were further analyzed to determine the average performances in the study population. For men, grip strength peaked within the 20 to 39 years age group and gradually declined thereafter. For women, the highest mean grip strength measurement was recorded in the 40- to 49-year-old age group and then deteriorated with age.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Performance of normal Chinese adults on grip strength test: a preliminary study.

This study investigated grip strength performance in normal Chinese adults. Grip strength of 160 Chinese subjects (80 males and 80 females) from a major metropolitan city in southern Taiwan was measured with a newly calibrated Jamar dynamometer. The subject was tested in a standing position, with shoulder adducted and neutrally rotated, elbow flexed at 90 degrees and forearm and wrist in neutral position. Subjects exerted one maximal effort with both right and left hands. Results indicate that the grip strength of Chinese males peaked within the 20 to 39 year-old group. For Chinese females, the highest grip strength score occurred in the 40 to 49 year-old age group and declined as a function of age. Males consistently had higher grip strength than females across age ranges. Finally, there was no 10% variance in grip strength from the dominant to nondominant hand for each age group of both sexes. Instead, there were 49 (31%) of all subjects who had nondominant hand strength scores that were equal to or greater than their dominant hand strength scores. Clinical implications and recommendations for future research are suggested.

Adult↗
PubMed1993

Grip strength: relationship to shoulder position in normal subjects.

The objective of this study was to evaluate the effect of shoulder position on grip strength. A Jamar dynamometer was used to measure the grip strength of 160 subjects (80 males and 80 females), stratified on both sex and age, in the four testing positions. For each of the tests of grip strength, the subject stood with the shoulder adducted and neutrally rotated while the forearm and wrist were held in the neutral position. The four hand strength tests consisted of three positions in which the elbow was maintained in full extension combined with varying degrees of shoulder flexion (i.e., 0 degree, 90 degrees, and 180 degrees) and of one position in which the elbow was flexed at 90 degrees with the shoulder in 0 degree of flexion. Only the dominant hand was tested. The results showed that the highest mean grip strength measurement was recorded when the shoulder was positioned at 180 degrees of flexion with elbow in full extension; whereas the position of 90 degrees elbow flexion with shoulder in 0 degree of flexion had the lowest grip strength score. In addition, the grip strength measured with the elbow in extension, regardless of shoulder position (i.e., 0 degree, 90 degrees, and 180 degrees of flexion), was significantly higher than when the elbow was flexed at 90 degrees with the shoulder positioned at 0 degree of flexion. Finally, grip strength differed significantly for both sexes and for each age group. The findings are valuable in the evaluation and rehabilitation training of hand injured patients.

Adult↗
PubMed1991

Anti-implantation activity of S(-)- and R(+)-camphor-yuehchukene in rats.

(+/-)-Yuehchukene is a dimeric indole alkaloid with potent anti-implantation activity in rats. Since (+/-)-yuehchukene occurs in nature as a racemate, it would be desirable to find out which enantiometer is the bio-active form. To this end, S(-)-camphor-yuehchukene and R(+)-camphor-yuehchukene were synthesised and tested in three bioassay models. It was found that the R(+) enantiomer was the active form. It was equipotent with (+/-)-yuehchukene in both anti-implantation and estrogenic activity tests. It seems fair to conclude that both activities reside in the same molecule.

Alkaloids↗
PubMed1989

Antifertility principle of Ruta graveolens.

Chloroform extracts of the root, stem and leaf of Ruta graveolens L. showed significant anti-fertility activity in rats when administered intragastrically on days 1-10 post-coitum. Fractionation of the extracts led to the isolation of chalepensin as the active component with some toxicity. Time-dosing experiments demonstrated that chalepensin acts at the early stages of pregnancy. It is not clear at this stage if the anti-fertility effect is a direct manifestation of chalepensin toxicity.

5-Methoxypsoralen↗
PubMed1986

Sources of the anti-implantation alkaloid yuehchukene in the genus Murraya.

The genus Murraya has been widely used in traditional medicine in east Asia. In view of the recent isolation of the anti-implantation alkaloid yuehchukene from M. paniculata a search has now been made for other natural sources of this alkaloid within the genus. In this paper we report findings for nine taxa of Murraya.

Alkaloids↗
PubMed1979

Leonurine, an improved synthesis.

Leonurine (1) is the uterotonic principle of Leonurus artemisia. We have developed a simple, high-yield synthetic procedure of 1 that is adaptable to large scale preparation. The synthesis involves the condensation of syringic acid and 4-guanidino-1-butanol hydrochloride in the presence of DDC using 1:1 HMPT-ether as solvent. The synthetic leonurine showed uterotonic activity in vivo and in vitro.

Animals↗
PubMedDate not supplied

Yuehchukene, a bis-indole alkaloid, and cyclophosphamide are active in breast cancer in vitro.

Yuehchukene (YCK) is a novel bis-indole alkaloid with weak estrogenic activity. Biochemical studies showed that YCK could attenuate estrogenic action. In this study, the response of MCF-7, an estrogen-receptor-positive breast cancer cell line, under different combinations of estradiol, cyclophosphamide and YCK, was tested. From the dose-response curve, we discovered that 10(-2) M cyclophosphamide, even in its so-called 'bio-inert' form, could inhibit MCF-7 cell growth. However, the cytotoxic effect of cyclophosphamide was lost by reducing its concentration to approximately 1 x 10(-3) M. On the other hand, a low concentration ( approximately 10(-8)-10(-9) M) of YCK was found to potentiate the cytotoxic effect of cyclophosphamide on the MCF-7 cell line. Such an effect was absent in the estrogen-receptor-negative cell line MDA-MB-231. These findings, together with the dual role of a mixed estrogen and anti-estrogen effect, suggested that YCK and cyclophosphamide can be a potential combination in chemo-hormonal therapy for breast cancer.

Alkaloids↗
PubMedDate not supplied

Severe hypertension in hypoplastic kidney and bilateral renal artery stenosis: report of one case.

A three year-old boy was found incidentally to have severe hypertension (around 200/110 mmHg) when he was brought to This Hospital's Emergency Department because of his abdominal pain. After his admission, serial and detailed examinations were performed. These included: basic blood chemistry studies, abdominal and renal sonography, excretory urography, radionuclide scintigraphy and angiography with selective renal vein renin sampling. Diagnosis was made of renovascular hypertension with combination of unilateral renal hypoplasia and bilateral renal artery stenosis. The patient was given oral anti-hypertensive drugs, with resulting satisfactorily controlled blood pressure after two weeks of treatment. He was discharged without surgical intervention.

Child, Preschool↗