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Biomedical subjects

D Tse

Publications and source records attributed to D Tse.

12 recordsLinked to original sources
PubMed1996

Relative resistance to HIV-1 infection of CD4 lymphocytes from persons who remain uninfected despite multiple high-risk sexual exposure.

Some individuals remain uninfected with human immunodeficiency virus type-1 (HIV-1) despite multiple high-risk sexual exposures. We studied a cohort of 25 subjects with histories of multiple high-risk sexual exposures to HIV-1 and found that their CD8+ lymphocytes had greater anti-HIV-1 activity than did CD8+ lymphocytes from nonexposed controls. Further studies indicated that their purified CD4+ lymphocytes were less susceptible to infection with multiple primary isolates of HIV-1 than were CD4+ lymphocytes from the nonexposed controls. This relative resistance to HIV-1 infection did not extend to T-cell line-adapted strains, was restricted by the envelope glycoprotein, was not explained by the cell surface density of CD4 molecules, but was associated with the activity of the C-C chemokines RANTES, MIP-1alpha, and MIP-1beta. This relative resistance of CD4+ lymphocytes may contribute to protection from HIV-1 in multiply exposed persons.

CD4-Positive T-Lymphocytes↗
PubMed1991

Uncoupling of attenuated myo-[3H]inositol uptake and dysfunction in Na(+)-K(+)-ATPase pumping activity in hypergalactosemic cultured bovine lens epithelial cells.

Attenuation of both the active transport of myo-inositol and Na(+)-K(+)-ATPase pumping activity has been implicated in the onset of sugar cataract and other diabetic complications in cell culture and animal models of the disease. Cultured bovine lens epithelial cells (BLECs) maintained in galactose-free Eagle's minimal essential medium (MEM) or 40 mM galactose with and without sorbinil for up to 5 days were examined to determine the temporal effects of hypergalactosemia on Na(+)-K(+)-ATPase and myo-inositol uptake. The Na(+)-K(+)-ATPase pumping activity after 5 days of continuous exposure to galactose did not change, as demonstrated by 86Rb uptake. The uptake of myo-[3H]inositol was lowered after 20 h of incubation in galactose and remained significantly below that of the control throughout the 5-day exposure period. The coadministration of sorbinil to the galactose medium normalized the myo-[3H]inositol uptake. No significant difference in the rates of passive efflux of myo-[3H]inositol or 86Rb from preloaded galactose-treated and control cultures was observed. Culture-media reversal studies were also carried out to determine whether the galactose-induced dysfunction in myo-inositol uptake could be corrected. BLECs were incubated in galactose for 5 days, then changed to galactose-free physiological medium with and without sorbinil for a 1-day recovery period. myo-Inositol uptake was reduced to 34% of control after 6 days of continuous exposure to galactose. Within 24 h of media reversal, myo-inositol uptake returned to or exceeded control values in BLECs switched to either MEM or MEM with sorbinil.2+ reversible and occurred independently of changes in Na(+)-K(+)-ATPase pumping activity in cultured lens epithelium, indicating that the two parameters are not strictly associated and that the deficit in myo-inositol uptake occurs rapidly during hypergalactosemia.

Aldehyde Reductase↗
PubMed1991

Depletion of glutathione by L-buthionine sulfoximine does not promote inactivation of myo-inositol transport in cultured bovine lens epithelial cells.

Exposure of cultured bovine lens epithelial cells (BLECs) to minimal essential medium (MEM) containing 40 mM galactose (Gal) promotes a decrease in the cellular content of reduced glutathione (GSH) as galactitol increases. Incubation of BLECs with Gal also leads to a reduction in 3H-myo-inositol (3H-MI) concentrating capability. Studies were therefore initiated to determine the nature of the relationship between polyol accumulation, GSH content and the attenuation of the active transport of myo-inositol. The inhibitor of glutathione biosynthesis, L-buthionine sulfoximine (L-BSO) was used in order to lower the intracellular pool of GSH in MEM-maintained cells to a concentration below that characteristically observed in Gal-treated cells, under conditions whereby no galactitol accumulation could or had occurred. L-BSO (0.5 mM) was simultaneously administered to BLECs maintained in either MEM or Gal for up to five days. The cellular content of GSH after five days of continuous incubation was 3.3 micrograms GSH/micrograms PO4 in MEM alone and 0.45 microgram GSH/microgram PO4 in MEM + BSO. Moreover, the GSH content in BLECs exposed to Gal for five days was 1.9 micrograms GSH/micrograms PO4 and was not detectable in the Gal + BSO-treated cells. However, the ability to concentrate 3H-MI in MEM + BSO-treated BLECs was equivalent to that observed with MEM-maintained cells regardless of the significant difference in GSH content. Likewise, L-BSO addition to Gal-treated cells, while virtually depleting the intracellular GSH content, did not further decrease the ability of the cells to accumulate 3H-MI compared to that observed with BLECs in Gal alone. Indeed, supplementation of Gal-treated cells with exogenous GSH failed to correct the Gal-induced attenuation in myo-inositol concentrating ability. These studies demonstrate that the Gal-induced depletion of cellular GSH and the Gal-induced deficit in ability to concentrate myo-inositol are not associated and represent independent events. That is, depletion of lens cell GSH does not lead to the attenuation of myo-inositol uptake in cultured lens epithelial cells.

Animals↗
PubMed1990

Sorbinil prevents the hypergalactosemic-induced reduction in [3H]-myo-inositol uptake and decreased [3H]-myo-inositol incorporation into the phosphoinositide cycle in bovine lens epithelial cells in vitro.

The synthesis of phosphatidylinositol, phosphatidylinositol-4-phosphate and phosphatidylinositol-4-5-bisphosphate was studied using 3H-myo-inositol (3H-MI) as precursor in cultured bovine lens epithelial cells (BLECs) maintained in galactose-free, physiological medium or 40 mM galactose (Gal) +/- sorbinil for six days. The formation of inositol polyphosphates from phosphoinositides was also shown. Galactitol did not exceed 2mM in Gal-incubated cells after six days of exposure; no galactitol was observed in BLECs maintained in galactose-free, physiological medium or Gal supplemented with sorbinil. Uptake of 3H-myo-inositol(3H-MI) into BLECs was significantly reduced in cells exposed to Gal. A concomitant reduction in 3H-MI incorporation was observed in the phosphoinositides, as well as with the released inositol phosphates. The simultaneous addition of sorbinil to the Gal medium corrected the drop in 3H-MI uptake and normalized 3H-MI incorporation into the phosphoinositides and inositol phosphates. While an apparent decrease in the three inositol-containing lipids was observed with the Gal-incubated cells, based on 3H-MI incorporation, there was no change in total membrane phosphatidylinositol content when compared to cells maintained in physiological medium as determined by the microgram Pl PO4 per microgram total membrane PO4. The apparent loss of radiolabeled phosphoinositides was attributed to the decreased specific activity resulting from the lower internal pool of 3H-MI in the Gal-exposed cells available for incorporation into the phosphoinositides.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldehyde Reductase↗
PubMed1990

An unusual case of orbital cellulitis.

Munchausen's syndrome, an unusual disorder related to malingering and hysteria, is occasionally seen by the ophthalmologist. Munchausen patients deliberately deceive and attempt to manipulate physicians 'through factitious signs and symptoms. They know they are acting, yet appear unable to control their actions. Unnecessary medical workups and inappropriate surgical interventions are common with this perplexing syndrome. An unusual case of orbital cellulitis that illustrates a number of these features is illustrated and the syndrome is reviewed.

Adult↗
PubMed1990

The universal orbital implant: indications and methods.

Major criticisms of quasi-integrated implants, such as the Iowa Implant, have been the time-consuming surgical technique needed to implant the prosthesis, and the high rate of extrusion. The Universal Implant (Oculo-Plastik, Montreal) is designed with these concerns in mind. In addition, those qualities that produce the motility advantages of a quasi-integrated implant and the ease of placement of a sphere have been incorporated into the design of the Universal Implant. The Universal Implant also (1) uses a faster implantation technique at surgery, (2) avoids cleaning the muscles, (3) has smaller mounds that are lower and more rounded, and should decrease the late extrusion rate, (4) can be used as an evisceration implant, enucleation implant, or secondary implant, and (5) has a larger girth and radius on the posterior surface that, in turn, helps support orbital fat and tissues and results in a more natural superior sulcus. It is recommended that the Universal Implant be used by surgeons who were pleased with the Iowa Implant, as the Universal implant represents an excellent alternative with major advantages over most other enucleation implants.

Humans↗
PubMed1977

Hospital Salmonella johannesburg infection and its possible role in the community spread of the infection in Hong Kong.

Salmonella johannesburg (1, 40: b: e, n, x), a previously rare salmonella serotype, has established itself rapidly as an important and highly prevalent cause of gastroenteritis among children. The clinical features of the infection are usually mild but chronic. It has been suggested that S. johannesburg was introduced into Hong Kong through imported foods but no common vehicle could be traced as the source of infection. A thorough investigation of one paediatric ward in a general hospital revealed that non-infected patients admitted to the ward usually acquired S. johannesburg infection within 3-7 days, with or without symptoms. Thus hospital cross-infection could be a significant factor in contributing to its rapid spread in the community. Furthermore, the rapidity with which S. johannesburg spread was facilitated by (a) its tendency to produce a chronic infection, (b) its multiple resistance to antibiotics, and (c) the higher infectivity of S. johannesburg over other salmonellas endemic in this locality. These factors combined with the overcrowded conditions in many of the hospitals in Hong Kong facilitated the occurrence of hospital infection, which in its turn contributed to the spread of the infection in the local community.

Chronic Disease↗
PubMed1976

Neonatal infection due to Salmonella worthington transmitted by a delivery-room suction apparatus.

An outbreak of diarrhoea due to Salmonella worthington in five newborn babies, 5 weeks after a similar outbreak in 13 babies for which no cause had been found, occurred in the nursery of a maternity ward. The source of infection was traced to the contaminated rubber tubing of a mechanical suction apparatus. S. worthington was isolated from the rubber tubing and the Y connexion of the suction apparatus from which all the five infected babies had received suction. Reflux of contaminated amniotic fluid into the sterile catheter connected to the apparatus some time before use could have been the means of introducing the infected material to the oropharynx of the newborn babies, and amniotic fluid, acting as a good medium to support the growth of S. worthington, might be responsible for the long-lasting contamination.

Cross Infection↗