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Biomedical subjects

M M Wu

Publications and source records attributed to M M Wu.

At least 55 records · Page 3Linked to original sources
PubMed1990

Phrenic nerve transfer for treatment of root avulsion of the brachial plexus.

Phrenic nerve transfer was performed in 164 patients with root avulsion of the brachial plexus. The methods of operation consisted of phrenic nerve transfer to and anastomosis with the musculocutaneous nerve, the phrenic nerve bridging to the musculocutaneous nerve, phrenic nerve anastomosis with or bridging to the median nerve, and phrenic nerve anastomosis with other nerves. Follow-up of 65 patients for more than 2 years showed an effective rate of 84.6%. The result indicated that this operation has no deleterious effects on respiration, and the surgical effects are related to severity of injury, duration, mode of operation and patient's age.

Adolescent↗
PubMed1989

Phrenic nerve transfer for brachial plexus motor neurotization.

We report a series of 164 patients who underwent phrenic neurotization to elements of the brachial plexus with root avulsion injuries. Recipient nerves included musculocutaneous nerve in 125 patients (78 direct neurotizations and 48 with intervening autograft), median nerve in 10 patients, and a variety of other nerves in 28 patients. Sixty-five patients presented a follow-up period of 2 or more years. Of this group, 55 patients (84.6%) achieved a recovery of M-3 or better. We observed no long-term deleterious effects on respiratory function.

Adolescent↗
PubMed1989

Circulatory crisis in free toe-to-hand transfer and its management: I. Clinical experience.

On the basis of experience with 226 patients undergoing free toe transfer for reconstruction of the thumb and fingers, circulatory crises during and after surgery are analyzed and classified according to the time of crisis occurrence. Prompt re-exploration is indicated when the crisis occurs within 24 hr postoperative. Crises occurring 48 hr and more postoperative are usually due to vasospasm, and antispasmodic therapy should be instituted. Surgical intervention in these later cases may prove fruitless.

Finger Injuries↗
PubMed1989

Dose-response relation between arsenic concentration in well water and mortality from cancers and vascular diseases.

Age-adjusted mortality rates were analyzed to examine the dose-response relation between ingested arsenic levels and risk of cancers and vascular diseases among residents in the endemic area of blackfoot disease, a unique peripheral vascular disease associated with long-term exposure to high-arsenic artesian well water and confined to the southwestern coast of Taiwan. The arsenic levels in well water determined in 1964-1966 were available in 42 villages of the study area, while mortality and population data during 1973-1986 were obtained from the local household registration offices and Taiwan Provincial Department of Health. Age-adjusted mortality rates from various cancers and vascular diseases by sex were calculated using the 1976 world population as the standard population. A significant dose-response relation was observed between arsenic levels in well water and cancers of the bladder, kidney, skin, and lung in both males and females, and cancers of the prostate and liver in males. However, there was no association for cancers of the nasopharynx, esophagus, stomach, colon, and uterine cervix, and for leukemia. Arsenic levels in well water were also associated with peripheral vascular diseases and cardiovascular diseases in a dose-response pattern, but not with cerebrovascular accidents. The dual effect of arsenic on carcinogenesis and arteriosclerosis and the interrelation between these two pathogenic mechanisms deserve more intensive study.

Adolescent↗
PubMed1989

Variability in biological monitoring of solvent exposure. I. Development of a population physiological model.

Biological indicators of exposure to solvents are often characterised by a high variability that may be due either to fluctuations in exposure or individual differences in the workers. To describe and understand this variability better a physiological model for differing workers under variable industrial environments has been developed. Standard statistical distributions are used to simulate variability in exposure concentration, physical workload, body build, liver function, and renal clearance. For groups of workers exposed daily, the model calculates air monitoring indicators and biological monitoring results (expired air, blood, and urine). The results obtained are discussed and compared with measured data, both physiological (body build, cardiac output, alveolar ventilation) and toxicokinetic for six solvents: 1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene, benzene, toluene, styrene, and their main metabolites. Possible applications of this population physiological model are presented.

Adipose Tissue↗
PubMed1989

Variability in biological monitoring of organic solvent exposure. II. Application of a population physiological model.

A physiological population model is used to study the variability associated with the biological monitoring of solvent exposure. The model consists of a combination of a physiological compartmental model and statistical simulation technique. Variable components considered are: exposure concentration, physical workload, body build, liver function, and renal function. The model is applied to six solvents: trichloroethylene, tetrachloroethylene, methylchloroform, benzene, toluene, and styrene. Biological indicators and air monitoring are compared as predictors of exposure, both external and internal (uptake, brain concentration, reactive metabolite formation). It appears that the choice of the best indicator depends on the type of exposure which is to be predicted. The effects of the various factors, environmental, physiological, or metabolic, are quantified and discussed. It is shown that fluctuation in exposure plays a large part in the final variability of biological indicator results. Further improvements and applications of this population model are considered.

Benzene↗
PubMed1988

Retinol-regulated gene expression in human tracheobronchial epithelial cells. Enhanced expression of elongation factor EF-1 alpha.

Conducting airway epithelial cells requires vitamin A or its synthetic chemicals (retinoids) for their survival and for the expression of normal mucociliary functions. By using molecular cloning, we have shown that one of the effects of retinol on cultured human tracheobronchial epithelial (HTBE) cells is the enhancement (from 2- to 4-fold) of the mRNA encoding the elongation factor EF-1 alpha. Sequence analysis has shown that clone HT7, which was identified by differential hybridization procedures, contained a cDNA insert which encoded a protein closely resembling (81%) elongation factor EF-1 alpha from brine shrimp and completely identical to the published sequence of human elongation factor EF-1 alpha (Brands, H.H.G.M., Maassen, J.A., Van Hemert, F.J., Amons, R., and Moller, W. (1986) Eur. J. Biochem. 155, 167-171). Regions of homology of HT7 to EF-Tu from yeast mitochondria, plant chloroplasts, and Escherichia coli are also evident. A single RNA band at 1700 bases was observed for both untreated and retinol-treated HTBE cells, and for mouse liver and parotid glands when Northern transfer from denaturing agarose gel was probed with a 32P-labeled HT7 insert. An enhanced amino acid incorporation and increased protein content per cell for HTBE cells grown in the presence of retinol were observed. Results presented by these studies indicate that retinol may regulate the transcription of a factor required for translation.

Amino Acid Sequence↗
PubMed1988

Postrelational database implementation for newborn screening and tracking.

Development of microcomputer based systems for the management of data in newborn screening programs has posed special difficulties. This paper describes the specific requirements for implementing an effective newborn screening database system using a unique postrelational database system. This system has been developed by Neometrics Inc. for use by laboratories engaged in running high volume newborn screening programs, and is currently operational in a number of state health laboratories.

Database Management Systems↗
PubMed1986

Effects of retinoids on human bronchial epithelial cells: differential regulation of hyaluronate synthesis and keratin protein synthesis.

Respiratory tract epithelia are one type of tissue targeted by vitamin A. In this study the effects of vitamin A and its analogs (retinoids) on human bronchial epithelial (HBE) cells have been investigated in a serum-free hormone-supplemented medium. This serum-free medium, which was developed for the long-term cultivation of protease-dissociated HBE cells, consists of Ham's F12 nutrient medium supplemented with insulin, transferrin, epidermal growth factor, hydrocortisone, cholera toxin, and bovine hypothalamus extract. Under these in vitro conditions, retinoids specifically stimulate the synthesis and secretion of hyaluronate (HA) and alter the pattern of synthesis of keratin proteins. In regard to HA, the degree of stimulation ranges from two-fold to ten-fold and is concentration dependent. In regard to keratin proteins, the most prominent effects of retinoids are inhibition of synthesis of the 48 kd and 50 kd keratin proteins (corresponding to cytokeratins 16 and 14, respectively, in the catalog of human cytokeratins; Moll et al., 1982) and stimulation of synthesis of the 40 kd and 52-54 kd proteins. The data indicate that retinoid effects on HA and keratin protein synthesis occur at different levels. The stimulation of HA synthesis occurs immediately after the addition of retinoid and cannot be prevented by pretreatment with actinomycin D, whereas the alterations in the pattern of keratin protein synthesis appear later and are inhibited by treatment with actinomycin D at or before the administration of retinoid. This study demonstrates that HBE cultures maintained in the serum-free condition can serve as an in vitro model to elucidate the mechanisms of retinoid actions.

Bronchi↗
PubMed1986

Cerebellar granule cells in culture: monosynaptic connections with Purkinje cells and ionic currents.

Electrophysiological properties of cerebellar granule cells and synapses between granule and Purkinje cells were studied in dissociated cultures. Electrophysiological properties of neurons and synapses in the mammalian central nervous system are best studied in dissociated cell cultures because of good target cell visibility, control over the contents of the extracellular solution, and the feasibility of whole-cell patch electrode recording, which has been a powerful technique in analyzing biophysical properties of ionic channels in small cells. We have applied this whole-cell recording technique to cultured cerebellar granule cells whose electrophysiological properties have been almost unknown because of their small cell size. In this study, simultaneous intracellular recordings from presynaptic granule and postsynaptic Purkinje cells demonstrated that granule cells made functional monosynaptic connections with Purkinje cells in dissociated cell cultures. Further, the existence of Na, Ca, and K channels in granule cells is demonstrated by external ion substitutions.

Animals↗