Search PubMed⌕ Search

Biomedical subjects

S Lai

Publications and source records attributed to S Lai.

At least 145 records · Page 8Linked to original sources
PubMed1992

Vacuolar H(+)-translocating ATPases from plants: structure, function, and isoforms.

The vacuolar H(+)-translocating ATPase (V-type ATPase) plays a central role in the growth and development of plant cells. In a mature cell, the vacuole is the largest intracellular compartment, occupying about 90% of the cell volume. The proton electrochemical gradient (acid inside) formed by the vacuolar ATPase provides the primary driving force for the transport of numerous ions and metabolites against their electrochemical gradients. The uptake and release of solutes across the vacuolar membrane is fundamental to many cellular processes, such as osmoregulation, signal transduction, and metabolic regulation. Vacuolar ATPases may also reside on endomembranes, such as Golgi and coated vesicles, and thus may participate in intracellular membrane traffic, sorting, and secretion. Plant vacuolar ATPases are large complexes (400-650 kDa) composed of 7-10 different subunits. The peripheral sector of 5-6 subunits includes the nucleotide-binding catalytic and regulatory subunits of approximately 70 and approximately 60 kDa, respectively. Six copies of the 16-kDa proteolipid together with 1-3 other subunits make up the integral sector that forms the H+ conducting pathway. Isoforms of plant vacuolar ATPases are suggested by the variations in subunit composition observed among and within plant species, and by the presence of a small multigene family encoding the 16-kDa and 70-kDa subunits. Multiple genes may encode isoforms with specific properties required to serve the diverse functions of vacuoles and endomembrane compartments.

Amino Acid Sequence↗
PubMed1992

Survival and disease progression in human immunodeficiency virus-infected women after an index delivery.

OBJECTIVE: Our objective was to provide information on survival and disease progression in human immunodeficiency virus antibody-positive pregnant women undergoing prospective evaluation. STUDY DESIGN: After an index delivery, 103 human immunodeficiency virus antibody-positive pregnant women were identified and underwent follow-up for 3 years. The patients were assessed medically and/or gynecologically when hospitalized for a human immunodeficiency virus-related illness or at each follow-up visit. The life-table method was used to estimate the cumulative probabilities of survival and remaining free of acquired immunodeficiency syndrome. Cox's proportional-hazards analyses were used to identify prognostic factors for survival and progression to acquired immunodeficiency syndrome. RESULTS: The majority of human immunodeficiency virus-infected pregnant women were alive 3 years later. Lymphadenopathy syndrome or herpes genitalis was significantly associated with a subsequent diagnosis of acquired immunodeficiency syndrome. Of the 103 original patients, six had acquired immunodeficiency syndrome at the index delivery and acquired immunodeficiency syndrome developed in 24. Approximately 94% of evaluable patients with development of acquired immunodeficiency syndrome had CD4-lymphocyte counts < 200/mm3. The most common opportunistic infection was Pneumocystis carinii pneumonia. Acquired immunodeficiency syndrome and postpartum zidovudine therapy were independent prognostic factors affecting survival. CONCLUSION: Survival was affected by Centers for Disease Control group status of human immunodeficiency virus infection at the index delivery.

AIDS-Related Complex↗
PubMed1991

Human T-cell lymphotropic virus infection among blood donors in south Florida. The Transfusion Safety Study Group.

Knowledge of the epidemiologic pattern of human T-lymphotropic virus (HTLV) in the United States is being enlarged by blood donor screening. We tested stored sera from 29,937 donations made in South Florida in 1984-1985. Twenty-three donors were confirmed as seropositive, a prevalence of 0.8 per 1,000 donations. Specificity was supported by serologic retesting and virus culture of 11 donors located for follow-up. Sex- and age-specific prevalences did not differ significantly; blacks, however, accounted for 65% of seropositive donations. Within South Florida, one section of Miami had a prevalence of 4.5 per 1,000 donations, significantly above the 0.1 to 1.1 per 1,000 rates for other parts. An epidemiologic association with known HTLV-I endemic areas could account for most infections; all seven typed isolates were characterized as HTLV-I. Exposures, however, were diverse, sometimes multiple, and had no necessary relationship to personal lifestyle. This finding suggests that sources of infection were varied. Seropositive family members emphasize familial clustering of HTLV-I infection.

Adult↗
PubMed1991

[Changes in the internal limiting retinal membrane after epiretinal peeling].

The authors describe the histological features of an extensive epiretinal membrane surgically removed from an eye with posterior penetrating ocular trauma. A pars plana vitrectomy and removal of the epiretinal membrane were performed. Histological preparations revealed a large segment of internal limiting membrane (ILM) adherent to the epiretinal membrane. This case report illustrates two points: the adherence between ILM and Muller cells is quite weak; removal of extensive portions of ILM could encourage rapid re-proliferative phenomena.

Cell Membrane↗
PubMed1990

A new therapeutical approach to central serous retinopathy, a hypothesis.

The authors report two cases of patients affected by Central Serous Retinopathy (C.S.R.) lasting few days; they were immediately started with an antiviral therapy (Acycloguanosine) for few days and in both cases the regression of symptoms and a flat retina were observed after a very shorter time than the spontaneous course. A fluorescein angiography confirmed a healing of the leaking points very few days after the therapy was discontinued. The authors discuss their finding in relation to the latest hypothesis on C.S.R. pathogenesis.

Acyclovir↗
PubMed1990

Immunohistochemical characterization of extracellular matrix components of yolk sac tumors.

Proteoglycans (PGs) were isolated from yolk sac tumor and chondroitin sulfate large PG (core molecule with a molecular weight congruent to 200,000) and small PG (core molecule with a molecular weight congruent to 50,000) were detected. Immunohistochemical localization of PGs in three yolk sac tumors was investigated using monoclonal antibodies raised against both small and large PGs, which were purified from human ovarian fibroma capsule and a yolk sac tumor, respectively. The localization of large PG was observed to be distinct from that of small PG. A markedly positive reaction for antibody against large PG was observed in myxomatous areas, perivascular and perivesicular portions; hyaline globules were the most intensely reactive. In the areas showing a polyvesicular vitelline tumor pattern, the compact connective tissue stroma consisted of small PGs. It is conceivable that large PGs are synthesized by immature mesenchymal cells and also by epithelial-like cells as a basement membrane component, whereas small PGs are synthesized by mature fibroblastic cells synthesizing collagen. Immunohistochemical localization of other extracellular matrix components (laminin, fibronectin, type I-IV collagen) was also studied in relation to PG localization.

Adult↗
PubMed1990

Aneurysmal bone cyst of the mandible--a case report.

Aneurysmal bone cysts originating in the craniofacial region have seldom been reported in Taiwan. A case of aneurysmal bone cyst arising in the right mandible of a 15-year-old Chinese boy was presented with both the roentgenographic and microscopic findings. In view of the high recurrent rate and the large destructive mandibular lesion, segmental resection with immediate bone grafting for reconstruction and a conscientious follow up regimen was employed. The etiology and pathogenesis of this interesting lesion remained unclear but several theories were reviewed and the differential diagnosis of this lesion was also discussed. Furthermore, immunoperoxidase staining for Factor VIII related antigen was performed to help differentiate between the aneurysmal bone cyst and a central hemangioma and then to elucidate the pathogenesis of the former.

Adolescent↗
PubMed1989

[Senile macular degeneration: surgical management and histopathologic features].

Choroidal neovascularization often complicates senile macular degeneration; argon and krypton laser photocoagulation are very useful to stop visual acuity decrease caused by extrafoveal choroidal neovascular membrane (NVM) in a large group of patients. Unfortunately, in a large number of cases, NVM causes haemorrhagic serous detachment, disciform scar and, sometimes, vitreous hemorrhage. In these patients it is impossible to perform laser treatment. A three ports pars-plana vitrectomy has been performed for the treatment of intravitreal hemorrhage in a case of haemorrhagic disciform lesion and in two cases of extensive subretinal haemorrhage secondary to subretinal NVMs. Posterior pole focal retinotomies have been created to remove the NVMs in order to prevent further hemorrhages; an internal tamponade has been performed and the retinotomies closed with endophotocoagulation or endocryo. The specimen of the membranes, stained for light microscopy, have been studied. During the months of follow-up (9 months) no subretinal membrane no retinal detachment developed but fibrosis at the retinotomy sites led to traction on the macula. The functional aim of this surgery is limited to the restoration of a clear vitreous and to a reduction in the diameter of the central scotoma in the cases of a recent subretinal haemorrhage.

Aged↗
PubMed1988

Breast cancer in relation to early use of oral contraceptives. No evidence of a latent effect.

A long-term effect of oral contraceptives (OCs) on breast cancer risk has been suggested as an explanation for some studies' failure to detect an association between OCs and breast cancer. To address this latency hypothesis, we analyzed data on 4714 case subjects and 4540 control subjects from the population-based Cancer and Steroid Hormone Study. No support was evident for a latent effect of OCs on breast cancer risk through age 54 years: among parous women who had cumulated more than six years of OC use before their first term pregnancy, the risk of breast cancer, relative to nonusers before first term pregnancy, was 0.6 at zero to four years after first term pregnancy (95% confidence interval [Cl], 0.2 to 1.8), 0.7 at five to nine years (95% Cl, 0.3 to 1.7), and 1.1 at ten to 14 years (95% Cl, 0.3 to 3.9). Among nulliparous women with more than six years of OC use in total, the relative risk of breast cancer, by interval from last use of OCs, was 1.3 at zero to four years (95% Cl, 0.8 to 2.0), 1.1 at five to nine years (95% Cl, 0.5 to 2.0), and 0.6 at ten to 14 years (95% Cl, 0.1 to 3.7).

Adult↗
PubMed1986

Percutaneous gastrostomy in a child.

A 2-year-old girl with cyanotic congenital heart disease needed to undergo gastrostomy. To avoid the use of general anesthesia, a percutaneous gastrostomy was performed as an interventional radiologic procedure with the patient under sedation and with the use of local anesthesia. The placement of a nasogastrocutaneous guide wire under fluoroscopic guidance provided a stable tract for placement of the gastrostomy tube.

Child, Preschool↗