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Biomedical subjects

W W Chen

Publications and source records attributed to W W Chen.

At least 73 records · Page 4Linked to original sources
PubMed1983

Skeletal abnormalities in mitral-valve prolapse.

One hundred and fifteen Chinese patients with mitral-valve prolapse were evaluated for skeletal abnormalities, to determine their prevalence and interrelation. Measurements of thoracic dimensions from radiographs differed significantly from the normal population. The commonest thoracic abnormality was the straight back, being present in 37.5% of the male and 26.9% of the female patients. Accurate quantitation of thoracic kyphosis was difficult. Either the ratio between antero-posterior and transverse thoracic diameters or a vertebral index characterised the straight back. Other abnormalities included scoliosis, sternal and rib deformities. The mean of metacarpal indices for the patients was also significantly higher than the normal mean. An abnormal metacarpal index was present in 20.9%. There was dissociation between peripheral and thoracic skeletal abnormalities. The diagnostic, aetiological and prognostic implications of associated skeletal abnormalities were discussed.

Adolescent↗
PubMed1983

Intravenous ranitidine has no hemodynamic effects in subjects with normal lung function and patients with chronic obstructive airway disease.

Ten patients with Chronic Obstructive Airway Disease (COAD) and five subjects with duodenal ulcers and normal lung function were given 50 mg ranitidine as a single intravenous bolus injection. Hemodynamic responses were continuously monitored. There were no significant alterations in systemic and pulmonary pressures, systemic and total pulmonary vascular resistances or cardiac output. Continuous ECG recordings did not reveal arrhythmias. Ranitidine does not appear to cause any significant disturbance of hemodynamic function in COAD patients. This contrasts with alterations in hemodynamics previously observed following administration of cimetidine.

Adult↗
PubMed1983

Myelin membrane from adrenoleukodystrophy brain white matter--biochemical properties.

Adrenoleukodystrophy (ALD) is an X-linked progressive neurological disorder characterized by the accumulation of saturated very-long-chain fatty acids (C24 to C30) in lipids, especially cholesterol esters of the brain white matter and adrenal cortex. In the present study we have investigated the localization of accumulated cholesterol esters in brain white matter. During isolation of purified myelin membrane from regions of active demyelination, significant enrichment in cholesterol ester was found in two fractions, mainly in a low-density floating fraction and to a lesser degree in the purified myelin preparation. The fatty acid composition of cholesterol esters from both the ALD floating and myelin fractions was enriched approximately 10-fold in saturated very-long-chain fatty acids (greater than or equal to C24) compared with control preparations.

Adrenoleukodystrophy↗
PubMed1983

Familial occurrence of mitral valve prolapse: is this related to the straight back syndrome?

Familial prevalence of mitral valve prolapse in a Chinese population was determined in 22 propositi of whom 10 had straight back (group A), three had abnormally high metacarpal index (group B), and nine had neither (group C). Of 71 (32 male and 39 female subjects) first degree relatives screened, mitral valve prolapse was found in 19 (seven male and 12 female subjects) (26.8%). The familial prevalence among groups A, B, and C was 20%, 30%, and 38.5%, respectively. Our study indicates that the familial occurrence of mitral valve prolapse does not depend on its association with the straight back syndrome.

Adolescent↗
PubMed1982

Is cardiac catheterisation necessary before valvular surgery?

The results of 269 patients who had undergone valvular operations during and 18-month period (January 1, 1980, to June 30, 1981) were analysed. One hundred and seventy-four patients referred for surgery had undergone routine cardiac catheterisation elsewhere, and these, together with four electively catheterised patients, constituted a group representing the conventional approach. Ninety-one patients were assessed only by clinical and non-invasive methods, including echocardiography, and were subjected to surgery without catheterisation. The two groups were comparable in their major clinical characteristics including age, sex ratio, functional class, previous history of closed mitral valvotomy, aetiology of valve lesions, and type of operative procedure performed. There was no discordance between operative finding and preoperative assessment, except in two patients of the catheterised group. Hospital mortality was acceptably low and was comparable between the two groups. Cardiac catheterisation is, thus, no longer necessary in the majority of patients undergoing surgery for valvular heart diseases.

Adult↗
PubMed1982

Abnormalities of lysosomes in human diploid fibroblasts from patients with Farber's disease.

An accumulation of ceramide associated with the deficiency of acid ceramidase has been demonstrated in cultured diploid skin fibroblasts from a patient with Farber's disease. We extend this observation to investigate the lysosomal localization of accumulated ceramide and the abnormalities of lysosomes caused by this ceramide accumulation in Farber's diseased fibroblasts. We have found that the lysosomal fraction isolated from Farber's diseased fibroblasts by a subcellular fractionation procedure is markedly low in density compared with that of normal fibroblasts and is separated from other subcellular organelles. Ultrastructural studies of the isolated lysosomal fraction from Farber's diseased fibroblasts showed a mixed population of intact and swollen vesicles with a lysosomal appearance. Examination under high magnification clearly demonstrated lysosomal inclusions which contain lamellar and curvilinear membranes and resembled those seen in the intact fibroblasts. Subcellular localization of Farber's fibroblasts showed that the accumulated [3H]ceramide from the culture medium was predominantly localized in the lysosomal fraction with a markedly low density and very little was found to be associated with other cellular membranes. Our finding that ceramide is accumulated in the lysosomal fraction of Farber's fibroblasts and that these cells also show membranous inclusions strongly suggests that the accumulation of ceramide is directly involved in the formation of lysosomal inclusions.

Acid Ceramidase↗
PubMed1982

Metabolism of ceramide-containing endocytotic vesicles in human diploid fibroblasts.

Two isoenzymes of ceramidase, including lysosomal acid ceramidase and nonlysosomal alkaline ceramidase, catalyze the degradation of ceramide in cultured human skin fibroblasts. A genetically determined disorder of sphingolipid metabolism (Farber's-disease) is characterized by the deficiency of acid ceramidase and by the pathological accumulation of ceramide. In this report, we take advantage of this genetic deficiency to study the intracellular transport of reconstituted low density lipoprotein (LDL) containing ceramide and of ceramide-containing liposomes into lysosomes. Our findings show that there is decreased incorporation of LDL in Farber's diseased fibroblasts, presumably related to the lack of lysosomal degradation of ceramide. In turnover experiments, the deficiency of lysosomal acid ceramidase in Farber's disease fibroblasts leads to the complete lack of degradation of ceramide internalized through the LDL uptake process. In contrast, this genetic defect does not affect either the uptake or turnover of ceramide-containing phosphatidylcholine liposomes. Comparison of these results suggests that in cultured skin fibroblasts the coated vesicles containing ceramide-LDL are designated for lysosomal delivery and are clearly distinguished from endocytotic vesicles involved in the uptake of ceramide-containing liposomes, which may be destined to be transported into subcellular organelles other than lysosomes.

Acid Ceramidase↗
PubMed1982

Mitral valve prolapse and pre-excitation.

Two out of 118 patients with mitral valve prolapse were found to have pre-excitation. The presence of mitral valve prolapse in one patient with Lown-Ganong-Levine syndrome and the persistence of prolapse in the presence and absence of pre-excitation in another patient with intermittent type B Wolff-Parkinson-White syndrome suggest that mitral valve prolapse in pre-excitation syndrome may not be secondary to the abnormal activation pattern of the left ventricle, which has been suggested as a possible mechanism by some investigators.

Adolescent↗
PubMed1982

Studies on the origin of human amniotic fluid cells by immunofluorescent staining of keratin filaments.

Cultivated cells obtained by amniocentesis for antenatal diagnosis were examined for the presence of keratin filaments by immunofluorescent staining techniques. In primary cultures, cells in fibroblast type colonies do not possess keratin filaments whereas cells in epithelial type colonies show positive staining of keratin fibres. The majority of cells in amniotic fluid type colonies also stain positively with antikeratin antibody. After the primary cells have been subcultured, most of them appear fibroblastic yet stain positively with antikeratin antibody. The patterns formed by these stained fibres resemble those seen in primary cultures of amniotic fluid type cells. These results indicate that the amniotic fluid type cells (which predominate in primary cultures) and the majority of cells in subcultures (routinely used for antenatal diagnosis of genetic metabolic disorders) are epithelial in origin.

Amniotic Fluid↗
PubMed1982

Pregnancy in patients with prosthetic heart valves: an experience with 45 pregnancies.

Between 1974 and 1981, 27 patients became pregnant after prosthetic heart valve replacement with a total of 45 pregnancies. Four pregnancies terminated in therapeutic abortions. Of the remaining 41 pregnancies, 30 were associated with the use of anticoagulants and 11 not. Haemorrhage related to anticoagulant therapy occurred in one patient. The foetal loss in the group with anticoagulant therapy was 33 per cent (10 abortions) and that in the group without was 9 per cent (one abortion). The use of aspirin and dipyridamole during pregnancy (eight pregnancies) did not appear to threaten the outcome of pregnancy. A total of 30 babies were born alive and 20 per cent of them were light for date. There was no perinatal mortality. The typical warfarin embryopathy was not found. Congenital anomalies in four newborns included congenital hydrocephalus, harelip and complete cleft palate, bilateral accessory auricles and bilateral incurving 5th fingers. Subsequently, all except the newborn with congenital hydrocephalus showed normal developmental milestones.

Abortion, Spontaneous↗
PubMed1978

Enzymatic synthesis of a glucose-containing oligosaccharide-lipid involved in glycosylation of proteins.

Earlier studies on the biosynthesis of an oligosaccharide-lipid with the structure (alpha-Man)4-6-beta-Man-(1 leads to 4)-beta-GlcNAc-(1 leads to 4)-GlcNAc-P-P-dolichol have been extended to show that enzymes in membrane preparations of hen oviduct catalyze synthesis of a Glc-containing oligosaccharide-lipid that is similar in properties to the Glc-free oligosaccharide-lipid. Conditions that enable enzymatic preparation of Man-, GlcNAc-, or Glc-labeled oligosaccharide-lipid have been established. Experiments with isolated [Glc-14C]oligosaccharide-lipid as substrate demonstrated that the oligosaccharide chain was transferred en bloc from the lipid to an endogenous membrane protein of apparent Mr = 25,000. In addition, an exogenous soluble protein, S-carboxymethylated alpha-lactalbumin, was shown to serve as acceptor of the oligosaccharide chain from the Glc-containing oligosaccharide-lipid. Studies on the metabolic fate of the Glc residues in these proteins are reported in the accompanying paper (Chen, W. W., and Lennarz, W. J. (1978) J. Biol. Chem. 253, 5780-5785).

Animals↗
PubMed1978

Enzymatic excision of glucosyl units linked to the oligosaccharide chains of glycoproteins.

Studies in the accompanying paper (Chen, W. W., and Lennarz, W. J. (1978) J. Biol. Chem. 253, 5774-5779) showed that hen oviduct membranes catalyze synthesis of a Glc-containing oligosaccharide-lipid and that the oligosaccharide moiety of this compound is transferred en bloc to an endogenous protein as well as to an exogenous, soluble protein. In this study we have established that the endogeneous proteins in oviduct membranes are devoid of Glc. In view of these findings, the possibility that Glc was excised from the oligosaccharide chain after it had been transferred to protein was examined. Kinetic studies involving the use of endogenous membrane proteins as acceptors of the oligosaccharide chain suggested that the Glc residues were released without significant degradation of the core oligosaccharide. Direct evidence for the presence of a membrane-bound glucosidase was obtained using either free, Glc-containing oligosaccharide or Glc-containing oligosaccharide linked to S-carboxymethylated alpha-lactalbumin as substrates. Experiments utilizing [3H]Glc- and [14C]GlcNAc-labeled, glycosylated S-carboxymethylated alpha-lactalbumin established that, under conditions leading to extensive removal of [3H]Glc, there was essentially no degradation of the [14C]GlcNAc-labeled oligosaccharide core.

Animals↗