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Biomedical subjects

H Nguyen

Publications and source records attributed to H Nguyen.

At least 253 records · Page 14Linked to original sources
PubMed1985

Bacterial expression of the acquired immunodeficiency syndrome retrovirus p24 gag protein and its use as a diagnostic reagent.

A retrovirus [lymphoadenopathy-associated virus, human T-cell leukemia virus type III, acquired immunodeficiency syndrome (AIDS)-related virus] suspected of causing AIDS has been isolated recently. The detection of exposure to this retrovirus in donors of various blood products is important to prevent transmission of the disease from these donors to recipients. In the majority of cases, the detection of antibodies directed against either the viral core protein, a Mr approximately equal to 24,000 protein termed p24 gag, or the viral envelope antigen is proof of previous viral infection. Thus, we have expressed the p24 gag antigen in Escherichia coli in order to produce a diagnostic reagent for the detection of virus exposure. The bacterially synthesized antigen reacts with human and rabbit antisera directed against the native p24 gag protein in both electrophoretic transfer blot assay and ELISA. In addition, the use of bacterially produced antigens for ELISAs gave results that were comparable to those obtained by using antigens isolated from the virus.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Heparan sulfate proteoglycans from mouse mammary epithelial cells: localization on the cell surface with a monoclonal antibody.

Mouse mammary epithelial cells, of the normal murine mammary gland (NMuMG) cell line, bear a heparan sulfate-rich proteoglycan (HSPG) on their surfaces. A hybridoma (281-2) secreting a monoclonal antibody that recognizes this HSPG was produced by fusion of SP-2/0 myeloma cells with spleen cells from rats immunized with NMuMG cells. The 281-2 monoclonal antibody is directed against the core protein of the cell surface HSPG, as demonstrated by (a) recognition of the isolated proteoglycan but not its glycosaminoglycan chains, (b) co-localization of 281-2-specific antigen and radioactive cell surface HSPG on gradient polyacrylamide gel electrophoresis and on isopycnic centrifugation, and (c) abolition of immunofluorescent staining of the NMuMG cell surface by the intact, but not the protease-digested ectodomain of the cell surface HSPG. The antibody is specific for cell surface HSPG and does not recognize the HSPG that accumulates extracellularly beneath the basal cell surface. Therefore, the 281-2 antibody may be used to isolate the cell surface HSPG and to explore its distribution in tissues.

Aggrecans↗
PubMed1985

[Assessment of 7 years of automatic suturing in pulmonary surgery].

In 738 patients, the stapler-suturing methods were used in 2 main areas of concern: closure of the major hilar broncho-vascular structures (for smaller pulmonary vessels, we use absorbable ligating clips: Absolok from Ethicon and Polysurgiclip from USSC), suture of the lung parenchyma. Regarding pedicular sutures, our rate of bronchial fistula is 1,0% (or 4,4% if only pneumonectomies are taken into account: 1,4 on the left and 7,7 on the right). These rates are compared with those gathered from the literature, with emphasis on the right main bronchus. Regarding parenchymal sutures, we place TA and GIA on collapsed parenchyma for achieving a wide range of either intralobar or translobar procedures. We lay emphasis on: the conventional segmentectomies with stapling of the intersegmental surface, and the newer and more economical "non réglées" transsegmental resections in which the surgeon is anymore limited by segmental frontiers. The control of blood and air leakage from the cut surface is quite satisfactory, reducing significanthy the postoperative morbidity. For both major pedicular structures and fragile lung parenchyma, the stapler-suturing methods are very reliable and provide a quicker, simpler, safer, easier and more economical surgery in lung resections.

Bronchi↗
PubMed1984

Anatomical bases of transaxillary resection of the first rib.

Anatomical study of the costoclavicular space, with approach via inferolateral axillary route, allowing resection of the first rib. With the patient in the semisupine position, lifting the arm to the zenith allows the costoclavicular space to be opened widely and separation of the plane of the first rib from the neurovascular structures of the lateral wall of the axillary pyramid. In the first part of our work, we study successively the bony frame and its anatomical variations, the muscular frame and its anomalies, the cervical pleura and its associated fibromembranous complex. The second part is a succinct summary of the different stages of transaxillary resection of the first rib, with mention of the operative risks and landmarks in this approach.

Axilla↗
PubMed1984

Respiration in primary cultured cerebellar granule neurons and cerebral cortical neurons.

Respiration was measured polarographically in primary cultures enriched with cerebellar granule neurons or cerebral cortical neurons. The basal respiratory rate, measured on the sixth day after culturing, was 12.00 natom equiv. O/mg protein/min for the cortical neurons and 12.70 natom equiv. O/mg protein/min for the granule neurons. Maximal stimulation by 2,4-dinitrophenol produced a 20-40% increase over the basal rate for both neuronal types. Oligomycin inhibited neuronal basal respiration by 45%. These respiratory rates in neurons from primary culture are markedly lower than those measured in astrocytes grown under similar conditions.

Animals↗
PubMed1984

A two-year follow-up of a comparative trial of the cost-effectiveness of home and hospital psychiatric treatment.

The manpower and operating cost of home-based treatment was compared with the manpower and operating cost of hospital-based treatment during the second year and at the end of two years of treatment. Of the 155 patients destined to receive inpatient treatment, 76 were randomly assigned to home treatment, 79 to hospital treatment. The two groups were similar as to important social, demographic, and clinical characteristics, including psychiatric diagnosis. The manpower and operating cost of treatment, measured in two ways, was similar in the two groups during the second year. However, over the 2-year period hospital-based treatment of patients in each of the three diagnostic groups was more expensive than home-based treatment. Also, regardless of which treatment was given, the cost of treating schizophrenics was higher than the cost of treating manic-depressives which, in turn, was higher than the cost of treating individuals with depressive neurosis. Treatment failures were discussed. Over the 2-year period, failures in home-based treatment accounted for 39.1% of the total manpower and operating cost of home-based treatment, calculated according to Cost Model 1, and for 67.1% of the cost calculated according to Cost Model 2. The concept of failure in hospital-based treatment is also discussed.

Bipolar Disorder↗
PubMed1984

Maturation of resistance to lead encephalopathy: cellular and subcellular mechanisms.

The rat pup fed inorganic lead has been studied extensively as an animal model of human lead encephalopathy. As in man, the sensitivity of the brain to lead toxicity is age-dependent. Pups given daily lead feedings for one week beginning in the first week of life show pathologic changes (i.e., hemorrhage, edema, and neuronal necrosis) throughout the brain including the cerebral cortex and cerebellum. Pups begun on daily lead feedings for two weeks between 10-18 days of age show similar pathologic changes almost entirely confined to the cerebellum. Pups receiving very large quantities of lead for two weeks beginning at 20 or 24 days of age develop only minimal edema or no changes by light microscopy. We have proposed that the effects of lead on cellular aerobic energy metabolism are important in the pathogenesis of the encephalopathy in the developing brain. Early in the course of lead feedings begun at 14 days of age, isolated cerebellar mitochondria show a loss of respiratory control. During the second week of lead feedings, respiration with NAD-linked substrates is inhibited in cerebellar mitochondria, but not in cerebral mitochondria, from these animals. Cerebral mitochondrial respiration in pups fed lead from birth also is inhibited while both cerebral and cerebellar mitochondrial respiration in lead-fed adults is not affected. Isolated brain mitochondria exposed to lead in vitro show similar changes; an initial respiratory stimulation (probably reflecting an energy-coupled uptake of lead) and a secondary inhibition of dehydrogenases located in the mitochondrial matrix. Lead also may compete with calcium for brain mitochondrial carrier or binding sites. During maturation, the brain appears to become resistant to lead toxicity by sequestering lead away from the mitochondrial site of action. This hypothesis is based upon the observations that: 1. the in vitro effects of lead are the same in immature and mature cerebellar mitochondria; 2. the cerebral and cerebellar lead concentrations are the same in immature encephalopathic and mature encephalopathy-resistant lead-fed animals and; 3. cerebellar mitochondria from animals fed lead from 14 days of age contain much more lead than cerebral mitochondria from these animals and cerebellar mitochondria from lead-fed adults. This hypothesis is supported further by the results of recent electron microscopic and elemental microprobe studies of lead distribution in the brains of animals fed lead beginning at 14-18 days of age.(ABSTRACT TRUNCATED AT 400 WORDS)

Age Factors↗
PubMed1983

[5 new cases of solitary fibrous mesothelioma of the visceral pleura].

Five new cases of solitary fibrous mesothelioma of the visceral pleura support this review of the literature. Well encapsulated, mostly pedunculated, the implantation on the visceral pleura remains asymptomatic for a very long time and is more likely to be an incidental finding on a chest radiograph. Two extrathoracic signs are associated with certain huge tumors : hypoglycemia and osteoarthropathy. Histologic examination discloses whorls of collagen with scattered spindle-shaped cells. Electron microscope reveals characteristic features of both fibroblasts and mesothelial cells. Complete surgical removal is the best treatment for localized fibrous mesotheliomas of the visceral pleura. Recurrences after resection are rare and late recurrence, as long as 16 years after initial excision, usually behaves in a benign fashion.

Adult↗
PubMed1983

[Anatomical basis for the surgical use of the cephalic vein (V. Cephalica). 74 anatomical dissections. 189 surgical dissections].

The delto-pectoral portion of V. Cephalica was dissected 189 times during surgery and 74 times on cadavers. In 8 out of 10 cases the disposition was of the classical type and the diameter was wide enough to allow catheterization with a 3,4 mm catheter. In 2 out of 10 cases the vein was absent or toothin. This anomaly was most often unilateral with a normal disposition on the other side in 2/3 of cases.

Arm↗
PubMed1982

Rat cerebral cortical slice respiration in media of various osmolarities.

Freshly separated immature (5-day-old) and mature (60-day-old) rat cerebral cortical tissue demonstrates a Na+-dependent respiratory component similar to that recently described in primary cultured astrocytes. This respiratory component, which is not coupled to oxidative phosphorylation, increases as the osmolarity is increased above 354 mOsm in media with NaCl as the osmotic agent. With decreasing osmolarity from 354 to 80 mOsm, this respiratory component decreases more in cortical tissue than in cultured astrocytes. We propose that the respiratory response of neurons to decreasing extracellular osmolarity may differ from that of astrocytes in situ.

Animals↗
PubMed1982

In vitro cellular respiration at elevated temperatures in developing rat cerebral cortex.

Cellular respiration in vitro was studied in cerebral cortical tissue from rats 2-60 days of age. Respiration was measured polarographically over the temperature range 34-44 degrees C in tissue slices in a basal condition; maximally stimulated by an uncoupler of oxidative phosphorylation, dinitrophenol; and inhibited by a blocker of mitochondrial oxidative phosphorylation, oligomycin. Basal respiration at 34 degrees C increased about 80% between 7 and 30 days of age. Oligomycin-insensitive respiration did not change with age. Dinitrophenol-stimulated respiration was unchanged from 2 to 10 days and then increased over 100% between 10 and 15 days of age. The Q10 for dinitrophenol-stimulated respiration increased from a value of 1 in tissue from rats 2-10 days of age to about 2 in tissue from rats 15 days and older. Our results confirm the previously reported maturational increases in basal respiration and in respiratory capacity in rat cerebral cortical tissue. The maturational increase in maximal respiratory capacity occurs in a short age interval coincident with a marked increase in the Q10 for the hyperthermic temperature range. Both these properties may be important in the increasing resistance to hyperthermia-induced seizures and their functional sequelae in the rat pup.

Animals↗
PubMed1982

Development of resistance to lead encephalopathy during maturation in the rat pup.

The purpose of this study was to determine the maturational period during which the rat pup becomes resistant to the toxic effects of lead on the brain. Pups were fed lead, as lead acetate, by esophageal catheter for 14 days beginning at various ages between 14-24 days. The daily lead doses, which produced a hemorrhagic cerebellar encephalopathy in at least 50% of pups, were 400 micrograms Pb/g body weight for animals fed from 14 days of age, 800 micrograms/g for animals fed from 16 days, and 1600 micrograms/g for animals fed from 18 days. In contrast, pups fed even higher lead doses beginning at 20 days showed only a patchy cerebellar edema by light microscopy while pups fed from 24 days had normal cerebellums by light microscopy. The encephalopathic lead doses in the younger pups resulted in the same cerebellar lead concentrations (about 30 micrograms/g protein) as the higher lead doses fed pups beginning at 20 ot 24 days. When corrected for blood lead concentrations, the cerebellar lead concentrations were 20-25% higher in the encephalopathic compared to the older encephalopathy-resistant animals. This difference may be accounted for by cerebellar hemorrhages in the younger animals. Polarographic studies showed inhibition of respiration in cerebellar slices from animals fed lead from 14 days of age but not in animals fed from 20 or 24 days of age. Our results that, during the encephalopathy-sensitive age period, a critical cerebellar concentration of lead is associated with the encephalopathy. Resistance to lead encephalopathy in older animals, with similar cerebellar lead concentrations, may be related to a capacity to sequester lead in new cellular locations away from its site of action on aerobic energy metabolism.

Age Factors↗
PubMed1982

Maturation of potassium-stimulated respiration in rat cerebral cortical slices.

Maximal dinitrophenol-stimulated respiration and K+-stimulated respiration were measured polarographically in cerebral cortical slices taken from rats aged 2-60 days. Increasing K+ concentrations produced an increase in respiration in slices from animals aged 15 days and older, but not in slices from animals aged 10 days and younger. Dinitrophenol-stimulated respiration, or the maximal respiratory capacity of the tissue, showed a similar increase between 10 and 15 days of age. At each age the maximal respiratory capacity was 6-8 ng at 0/mg protein min greater than the maximal K+-stimulated respiration.

2,4-Dinitrophenol↗
PubMed1982

Cell volume regulation in the proximal convoluted tubule.

To evaluate the effect of hyper- and hypotonicity on proximal convoluted tubule (PCT) cell volume, nonperfused PCT were studied in vitro with hypertonic solutions containing sodium chloride, urea, or mannitol (450 mosmol/kg H2O) and with hypotonic low sodium chloride solutions (160 mosmol/kg H2O). When the tubules were subjected to hypertonic peritubular solutions containing NaCl, cell volume immediately decreased by 15.5% and remained constant throughout the experimental period (60 min). With mannitol, the initial decrease was identical to that with NaCl (17.7%), but the PCT volume increased slightly during the experimental period. With urea, the decrease in cell volume was smaller (7%) and transient. In hypotonicity, the PCT swelled rapidly, but this swelling was followed by a rapid regulatory phase in which PCT volume nearly returned to control values after less than 10 min. With a potassium-free peritubular medium or 10(-3) M ouabain, the regulatory phase of hypotonicity completely disappeared, whereas the cells did not maintain their reduced volume in NaCl-induced hypertonicity. These results suggest that Na-K-ATPase plays an important role in the maintenance of a reduced cellular volume in hypertonicity and in the regulatory phase of hypotonicity, probably by an active extrusion of sodium and water from the cell.

Animals↗
PubMed1982

A comparative trial of home and hospital psychiatric treatment: financial costs.

The financial costs of community-based treatment, stressing home treatment, were compared with the cost of hospital-based treatment during one year. Of 155 patients destined to receive inpatient treatment, 76 were randomly assigned to home treatment, 79 to hospital treatment; the two groups were similar as to important social, demographic, and clinical characteristics. The principal differences between the two treatments concerned the focus of treatment, the locale of treatment, the degree to which continuity of treatment was maintained, and the roles of the respective treatment staffs. Manpower and operating costs, measured in dollars, were estimated in two ways. Either way, hospital-based treatment was more expensive during the year: 64.1% more expensive (+3,250 vs. +1,980 per patient) in the first instance, 108.9% more expensive (+6,750 vs. +3,230 per patient) in the second. With two exceptions during the first month of treatment, the proportions of patients and families receiving either treatment who incurred other costs of treatment were low, and the differences between groups were not significantly different. A higher proportion of patients and families receiving home-based treatment defrayed the cost of the patient's psychotropic drugs; second, a higher proportion of families of patients receiving hospital-based treatment defrayed transportation costs. The proportions of patients and families incurring costs of the consequences of illness were low, and the differences between treatment groups were not significant. We compared this study with similar studies, discussed the generalizability of the results of this study and similar studies, and identified issues for future research.

Adolescent↗