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Biomedical subjects

K M Chan

Publications and source records attributed to K M Chan.

At least 217 records · Page 12Linked to original sources
PubMed1990

Epidemiology of shoulder impingement in upper arm sports events.

An epidemiological survey was conducted to collect data relating to the prevalence and frequency of shoulder pain and other related problems among different athletic groups that demanded vigorous upper arm activities. A questionnaire was administered on site thus ensuring that the response rate was 100 percent. Analysis of results revealed that of the 372 respondents there were 242 male (65.1 percent) and 130 female subjects (34.9 percent), with seven (1.9 percent) above the age of 40, 119 (32 percent) between the ages of 25 and 40, and 246 (66.1 percent) below 25 years of age. A total of 163 athletes (43.8 percent) indicated that they had shoulder problems, 109 (29 percent) suffering pain. Diffuse pain was indicated by 20 respondents (5.4 percent), while localized pain during movement was reported in 89 (23.9 percent). The prevalence of shoulder pain ranked highest among volley ball players (N = 28) followed by swimmers (N = 22), while badminton, basketball and tennis participants were equally affected (N = 10).

Adult↗
PubMed1990

Use of lower limb prosthesis among elderly amputees.

Forty-seven elderly patients (21 males and 26 females) with lower limb amputation, and with prostheses fitted were studied. Their ages ranged from 65 years to 91 years old, with an average of 75.4 years. The three most common contributory causes for amputation were diabetes mellitus, vascular occlusion and carcinoma of the skin. Among the lower limb amputations, below knee amputation was the most common (93.6%). About 30% of the patients developed complications from prostheses, the 3 most common in order of frequency were stump pain, pressure ulcers and stump infection. Male patients tended to do better with prostheses than female patients. More male patients wanted prostheses for mobility, while most female patients cited cosmesis as the reason for wanting a prosthetic leg. More male patients used the prostheses more frequently and this was associated with a higher level of function in terms of self care and mobility. Reasons for non-usage of prosthesis were poor-fitting sockets, floppy stump, stump ulcers and infection. Carers of male amputees tended to cope better than those caring for female amputees. Both the present age of patient, and the age at amputation were found not to be a factor in deciding the frequency of usage of prosthesis, and the outcome of success in rehabilitation of the amputee. Psychological factors played an important role in the outcome of rehabilitation. Eighty-five percent of patients who functioned at a lower level despite a relative lack of serious medical condition cited psychological reasons for their poor performance, among which were age and the 'expected' loss of mobility with amputation.

Aged↗
PubMed1990

Infection in the elderly.

One hundred and eleven patients with pyogenic infections were studied. Of these, 32 patients (28.8%) were diabetic, and 33 patients (30%) had positive cultures obtained. Fifty-eight patients (52.3%) had fever (T degrees greater than 37.2 degrees C) while 69 patients (62.2%) had leucocytosis. Forty-one patients (36.9%) had nosocomial infections. It was found that patients older than 75 years-old did not respond to infection by a febrile response as often as those younger than 75 years-old. Mortality rate was increased in those whose T degrees greater than 38.2 degrees C and in those with more than one source of infection. Age and the presence of diabetes was not found to increase the mortality rate, though diabetics tend to have more than one source of infection. A positive blood culture was also associated with a higher mortality rate. There were also more deaths among patients with nosocomial infection than the community acquired group. The three most common sources of infection were lung, urinary tract and skin respectively. The most common group of organisms cultured was gram negative bacilli, of which Klebsiella species was most frequently isolated. Of these, 57% of the Klebsiella sp cultured came from the nosocomial group. Staphylococcus aureus was the next most frequently cultured bacteria, and all these isolates (100%) came from the nosocomial group. Though antibiotics were started within 48 hours of suspicion of infection in majority of patients (101 patients or 91%), and all of these received appropriate initial antibiotics, mortality rate remained high (26 deaths or 23.4%).

Age Factors↗
PubMed1990

Acute sympathotonic orthostatic hypotension with recovery.

We describe a 30 year-old female who presented with severe orthostatic hypotension despite appropriate compensatory tachycardia on standing, following a viral infection. Clinical assessment and laboratory evaluation failed to detect other causes of her illness besides sympathotonic orthostatic hypotension. She responded to fludrocortisone and recovered completely after 3 months. We postulate that her acute reversible illness was due to a post-viral immunological response selectively affecting the alpha adrenergic receptors subserving the post-ganglionic sympathetic vasomotor fibres.

Acute Disease↗
PubMed1989

Chromosome mapping and expression of a putative testis-determining gene in mouse.

Isolation and mapping of a mouse complementary DNA sequence (mouse Y-finger) encoding a multiple, potential zinc-binding, finger protein homologous to the candidate human testis-determining factor gene is reported. Four similar sequences were identified in Hind III-digested mouse genomic DNA. Two (7.2 and 2.0 kb) were mapped to the Y chromosome. Only the 2.0-kb fragment, however, was correlated with testis determination. Polymerase chain reaction analysis suggests both Y loci are transcribed in adult testes. A 3.6-kb fragment was mapped to the X chromosome between the T16H and T6R1 translocation breakpoints, and a fourth (6.0 kb) was mapped to chromosome 10. Hence, mYfin sequences have been duplicated several times in the mouse, although they are not duplicated in humans.

Animals↗
PubMed1989

Male-enhanced antigen gene is phylogenetically conserved and expressed at late stages of spermatogenesis.

The male-enhanced antigen gene (Mea) was previously isolated from a mouse testicular cDNA library by using a pool of specific antisera against the serological H-Y antigen. The present studies characterize the human and mouse cDNAs and indicate that the MEA gene is conserved at both nucleic acid and protein levels. The corresponding mRNA encodes proteins of 18-20 kDa. The phylogenetic conservation could be extended to other mammalian species by Southern blot analysis. Although the Mea gene was transcribed as a 1-kilobase mRNA in most tissues, it was expressed at the highest level in adult testis. The testis-enhanced expression of the Mea gene was associated with germ cell development at late stages of spermatogenesis. Chromosome walking experiments identified two linked genes, A and B, located within 38 kilobases of human genomic sequence. Like the MEA gene, genes A and B were coordinately transcribed in the testis, which suggests that MEA and genes A and B are members of a gene family. In situ hybridization studies localized the MEA gene to the short arm of human chromosome 6 at band p21.1-21.3, close to the major histocompatibility complex locus. The genetic conservation and testis-specific expression of the MEA gene support the hypothesis that it plays an important role in mammalian spermatogenesis and/or testis development.

Amino Acid Sequence↗
PubMed1989

The putative testis-determining factor and related genes are expressed as discrete-sized transcripts in adult gonadal and somatic tissues.

The zinc-finger-Y (ZFY) gene is a candidate for the testis-determining-factor gene (TDF) on the human Y chromosome and is postulated to initiate testis differentiation during embryogenesis. However, the present study indicates that the ZFY gene and its X homologue (ZFX) are differentially expressed in adult tissues. A human testis-specific ZFY cDNA was isolated and completely sequenced. The corresponding ZFY transcript encodes a protein that has 801 amino acids and a calculated molecular weight of 90.6 kD. Expression analysis demonstrated that ZFY is transcribed primarily as 3- and 5.7-kb mRNA in testis and somatic cells, respectively. In contrast, the ZFX gene is expressed as a 5-kb transcript in the testis and as 6.7- and 8-kb transcripts in both ovarian and somatic tissues. With sets of gene-specific oligonucleotides, the origin and relative amount of the respective transcripts can be demonstrated in both Northern hybridization and reverse transcriptase-polymerase chain reaction analysis. Significantly, the 3-kb ZFY transcript was also detected in other mammalian adult testes. The testis-specific transcription of the ZFY gene hence suggests that it serves a conserved function in this organ.

Adult↗
PubMed1989

Pyroglutamic acidemia in an adult patient.

Pyroglutamic acidemia, a rare metabolic disorder, usually appears in infancy. It is characterized by retardation, ataxia, hemolytic anemia, and chronic acidosis and is caused by a marked deficiency of glutathione synthetase (EC 6.3.2.3) activity. This disease is inherited as an autosomal recessive trait, but the clinical condition is also detected in heterozygotes. We report an unusual case of high-anion-gap metabolic acidosis in a 52-year-old woman who was admitted with neurological complaints and breathing problems but without the characteristic clinical features of congenital glutathione synthetase deficiency. The etiology of the acidosis could not be attributed to ketoacidosis, lactic acidosis, or ingestion of methanol, salicylate, or ethylene glycol. Analysis of the patient's plasma and urine for organic acids revealed the presence of high concentrations of pyroglutamate (5-oxoproline), which remained high throughout her hospitalization.

Acidosis↗
PubMed1988

Differences in values obtained with 2 assays of prostate specific antigen.

Several different assays for prostate specific antigen have become available for use in clinical laboratories. We compared the 2 most widely used assays, the Tandem-R and the Pros-Check prostate specific antigen assays, to determine if different assays yield comparable results. We analyzed 70 serum specimens from patients with suspected or known prostatic carcinoma by both assays. Results from the assays showed close linear correlation (r equals 0.988) but the Pros-Check assay yielded values 1.85 times those of the Tandem-R test. The proportional bias between assays is owing to differences in the values assigned to calibration standards in the assays, and it demonstrates a need for improved standardization of prostate specific antigen assays. Important consequences of the bias between assays are that different normal ranges apply and that values from the 2 assays cannot be compared directly.

Antigens, Neoplasm↗
PubMed1988

Epstein-Barr virus (EBV)-associated undifferentiated carcinoma of the parotid gland.

A case of undifferentiated carcinoma of the salivary gland occurring in the parotid gland of a southern Chinese was reported. Tumour cells showed immunofluorescence for Epstein-Barr virus (EBV)-associated nuclear antigen, and DNA hybridization demonstrated the presence of EBV-DNA in tumour tissue. The findings in this case, together with previous reports, suggest a causal relationship between EBV and salivary gland carcinoma. The relationships between EBV and undifferentiated epithelial tumours of the salivary glands, nasopharynx and thymus are also discussed.

Adult↗
PubMed1988

Fractured proximal end of the femur in the elderly--a medico-social study.

278 geriatric patients with fractured proximal end of the femur were studied retrospectively 1.5-5 years (average 3.5 years) after they received treatment in two hospitals. Of the survivors 63%, 56% were totally pain-free while 15% had varying degrees of hip pain. Only 26.5% could squat fully. The physical activity was inversely proportional to the age. The widowed were doing better than the married with living husbands. Of the three methods of treatment (Austin-Moore hemiarthroplasty, plating and Ender's nailing), the hemiarthroplasty group of patients was doing the best physically. In spite of some positive X-ray findings among the different groups, corresponding clinical manifestations were not encountered.

Aged↗
PubMed1988

Pyogenic osteomyelitis of the spine--a review of 16 consecutive cases.

Pyogenic osteomyelitis of the spine is an uncommon disease. A series of 16 cases is reported. The site of involvement includes the lumbar, cervical, and thoracic segments, in that order of frequency of occurrence. Drug addiction and diabetes mellitus are important predisposing factors. The spectrum of clinical presentation is described. Late presentation is usually masked by old age, debilitation, and previous antibiotic treatment. Rapid progression with septicemia is also encountered. The importance of differentiating this condition from tuberculosis spondylitis is emphasized. Definitive diagnosis should depend on bacteriological, histological, and, with the recent introduction of antituberculosis antibody test, serological studies. Timely surgical intervention is indicated in complicated cases. Radical excision and anterior spinal fusion yields early and complete eradication of the infected material plus arthrodesis, which prevents late collapse of the spine.

Adult↗
PubMed1987

Effect of W7 on Ca2+ uptake and Ca2+-ATPase activities of the endoplasmic reticulum of rat liver.

In an initial attempt to use calmodulin antagonists as probes to study the role of calmodulin in the modulation of Ca2+ uptake activity in the endoplasmic reticulum of rat liver, we noticed that W7 had a differential effect on the Ca2+ uptake and Ca2+-ATPase activities. To test the specificity of this effect and explore the underlying mechanism, we examined the effects of W7 on Ca2+ accumulation and release by endoplasmic reticulum in both permeabilized hepatocytes and a subcellular membrane fraction (microsomes) enriched in endoplasmic reticulum. W7 reduced the steady-state Ca2+ accumulation in both preparations in a dose-dependent fashion but the half-maximal inhibitory concentrations were different for Ca2+ accumulation (90 microM) and Ca2+-ATPase activity (500 microM). Kinetic analysis indicated that the inhibition of both Ca2+ uptake and Ca2+-ATPase activity by W7 was noncompetitive with respect to Ca2+ and ATP. Addition of W7 did not enhance the rate of Ca2+ efflux from microsomes after Ca2+ influx had been terminated. The effect of W7 was apparently not related to its calmodulin antagonist properties as the phenomenon could not be demonstrated with the other more specific calmodulin antagonists, calmidazolium or compound 48/80. A similar observation with W7 has also been reported with the endoplasmic reticulum of pancreatic islets (B. A. Wolf, J. R. Colca, and M. L. McDaniel (1986) Biochem. Biophys. Res. Commun. 141, 418-425). We concluded that the effects of W7 on microsomal Ca2+ handling were not the result of increased membrane permeability to Ca2+ but rather were due to dissociation of Ca2+ uptake from Ca2+-ATPase activity.

Animals↗
PubMed1987

Mechanism of arachidonic acid-induced Ca2+ mobilization from rat liver microsomes.

Recent evidence indicates that unesterified arachidonic acid functions as a mediator of intracellular Ca2+ mobilization by inducing Ca2+ release from the endoplasmic reticulum of pancreatic islet beta cells in a manner closely similar to that of inositol 1,4,5-trisphosphate. To test the generality and explore the mechanism of this phenomenon we have examined the effects of arachidonic acid on calcium accumulation and release by hepatocyte subcellular fractions enriched in endoplasmic reticulum (microsomes). At concentrations above 0.017 mumol/mg microsomal protein, arachidonate induced rapid (under 2 min) 45Ca2+ release from microsomes that had been preloaded with 45Ca2+. Arachidonate also suppressed microsomal 45Ca2+ accumulation when present during the loading period, as reflected by reduction both of 45Ca2+ accumulation at steady state and of the rate of uptake. Neither the cyclooxygenase inhibitor indomethacin nor the lipoxygenase/cyclooxygenase inhibitor BW755C suppressed arachidonate-induced 45Ca2+ release, indicating that this effect was not dependent upon oxygenation of the fatty acid to metabolites. The long-chain unsaturated fatty acids oleate and linoleate were less potent than arachidonate in inducing 45Ca2+ release, and the saturated fatty acid stearate did not exert this effect. Albumin prevented 45Ca2+ release by arachidonate, presumably by binding the fatty acid. As is the case for inositol 1,4,5-trisphosphate, the ability of arachidonate to induce 45Ca2+ release was dependent on the ambient free Ca2+ concentration. Arachidonate did not influence microsomal membrane permeability or Ca2+-ATPase activity and may exert its effects on microsomal Ca2+ handling by activation of a Ca2+ extrusion mechanism or by dissociating Ca2+ uptake from Ca2+-ATPase activity.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1987

Roller skating--is it a dangerous sport?

A prospective survey of 111 cases of roller skating injuries within one year are reported. Males were more commonly injured than females. There was a high incidence (86%) of serious injuries, 28% of which required surgical treatment. The wrist (23%) was the commonest region involved, followed by the shoulder (20%), the elbow (15%) and the ankle (12%). Collision with other skaters and loss of control were the main factors leading to injury. Better rink discipline, instruction classes and safety publicity should be helpful in minimising accidents.

Adolescent↗
PubMed1987

Fatality due to acute hydrofluoric acid exposure.

Although hydrofluoric acid burns are frequent, fatality is rare. In the case of massive exposure, the prognosis is generally poor. We present two fatal cases resulting from extensive exposure to hydrofluoric acid which produced acute systemic metabolic acidosis with profound hypocalcemia and hypomagnesemia. Both patients died within three hours after the exposure. The current knowledge of treatment for severe hydrofluoric acid burns is reviewed and the importance of prevention and prompt recognition for proper treatment is emphasized.

Accidents, Occupational↗