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Biomedical subjects

S Tang

Publications and source records attributed to S Tang.

285 records · Page 16Linked to original sources
PubMedDate not supplied

Optical response of the indicator chlortetracycline to membrane potential.

Chlortetracycline is a fluorescent, Ca2+ indicator commonly used to monitor the internal Ca2+ concentration of membrane vesicles and organelles. We have found that the intensity of chlortetracycline fluorescence in the presence of Ca2(+)-loaded liposomes is dependent on the membrane potential of the vesicles as well as the intravesicular Ca2+ concentration. The fluorescence of chlortetracycline was lower when an inside-negative membrane potential was placed across the liposome membrane. Since chlortetracycline diffuses across the membrane in the zwitterionic form, the distribution of chlortetracycline across the membrane should not be strongly dependent on the membrane potential. However, because the proton permeability of phospholipid vesicles is relatively high, the intravesicular proton concentration is dependent on the membrane potential. The binding of Ca2+ to chlortetracycline is dependent on pH in the range of pH 6 to pH 8. Therefore, changes in the intravesicular pH as a result of a change in the membrane potential causes relatively large changes in the chlortetracycline fluorescence signal even when there isn't a change in the Ca2+ concentration.

Animals↗
PubMedDate not supplied

Is long-distance bird flight equivalent to a high-energy fast? Body composition changes in freely migrating and captive fasting great knots.

We studied changes in body composition in great knots, Calidris tenuirostris, before and after a migratory flight of 5,400 km from northwest Australia to eastern China. We also took premigratory birds into captivity and fasted them down to their equivalent arrival mass after migration to compare organ changes and nutrient use in a low-energy-turnover fast with a high-energy-turnover fast (migratory flight). Migrated birds were as economical as any fasting animal measured yet at conserving protein: their estimated relative protein contribution (RPC) to the energy used was 4.0%. Fasted birds had an estimated RPC of 6.8% and, consequently, a much lower lean mass and higher fat content for an equivalent body mass than migrated birds. Lean tissue was catabolized from most organs in both groups, except the brain. Furthermore, a principal components biplot showed that individuals were grouped primarily on the basis of overall organ fat or lean tissue content rather than by the size of specific organs. This indicates that organ changes during migratory flight are similar to those of a low-energy fast, although the length of the fast in this study probably accentuated organ reductions in some functional groups. Whether the metabolic characteristics of a flying migratory fast follow the three-phase model described in many inactive fasting animals is unclear. We have some evidence for skeletal fat being catabolized without phase 3 of a fast having been reached.

Analysis of Variance↗
PubMedDate not supplied

Folliculitis of the buttocks and pinworms. A case report.

Folliculitis, both superficial and deep, has increased in frequency, particularly during the warm months of the year. The frictional trauma from tight-fitting jeans, with overhydration and maceration of the skin, has contributed to the increase. Folliculitis is usually accompanied by pruritus, but when pruritus precedes the folliculitis, there may be another cause in addition to the wearing of tight clothes. Such was the case in our patient who had anal pinworms (Enterobius vermicularis).

Adult↗
PubMedDate not supplied

CAPD-associated peritonitis caused by Alcaligenes xylosoxidans sp. xylosoxidans.

Alcaligenes xylosoxidans is an uncommon cause of peritonitis in patients on maintenance continuous ambulatory peritoneal dialysis (CAPD). Peritonitis caused by A. xylosoxidans usually carries a poor prognosis because of the pathogen's virulence and its universal resistance to most antimicrobial agents. Even after early Tenckhoff catheter removal, the transport property of the peritoneum is often irreversibly damaged, leading to permanent technique failure. We report 2 patients with CAPD-associated peritonitis due to A. xylosoxidans sp. xylosoxidans who were successfully cured with a combination of piperacillin and tazobactam. One of them subsequently returned uneventfully to CAPD.

Adult↗
PubMedDate not supplied

Non-nutritive sucking behaviors in preschool children: a longitudinal study.

PURPOSE: Prolonged duration of non-nutritive sucking behaviors may have consequences in regard to the developing orofacial structures and occlusion. Little is known as to why some children have prolonged sucking habits beyond the first 2 to 3 years of life. This paper reports on non-nutritive sucking patterns among a large cohort of healthy children from birth to 36 months of age and older, and identifies factors predictive of prolonged non-nutritive sucking habits. METHODS: Over 600 children were followed from birth to at least 36 months of age using mailed questionnaires sent when children reached the ages of 6 weeks, and 3, 6, 9, 12, 16, and 24 months, and then yearly thereafter. Parents answered questions concerning non-nutritive sucking behaviors including use of pacifier and digit sucking. The study categorized children who maintained habits to 36 months of age or older as having prolonged habits, and using multivariate analyses, compared them to children without prolonged habits on various sociodemographic variables. RESULTS: The study found that for over 20% of the children, a non-nutritive sucking habit was prolonged to 36 months of age or older. Factors associated with prolonged sucking habits included older maternal age, higher maternal education level, and having no older siblings. CONCLUSIONS: Identifying factors related to prolonged non-nutritive sucking habits may be important in developing and targeting recommendations regarding such behaviors in an effort to prevent malocclusions that result from prolonged sucking habits.

Chi-Square Distribution↗
PubMedDate not supplied

Mycophenolate mofetil in the treatment of steroid-resistant primary focal segmental glomerulosclerosis.

We report our experience in using mycophenolate mofetil (MMF) for the treatment of steroid-resistant focal segmental glomerulosclerosis (FSGS) in two patients. Patient 1, who was treated on disease presentation, responded well with sustained complete remission. Patient 2, who had unsuccessful steroid treatment 4 yrs before and was re-treated with MMF, showed transient retardation in renal disease progression but eventually progressed to end-stage renal failure. Our observation illustrates that MMF could be useful in treating steroid-resistant FSGS if administered at an early phase of the disease, well before histologic damage becomes irreversible. Its efficacy requires validation in randomized, controlled trials. The current armamentaria for the treatment of this condition are also discussed.

Aged↗
PubMedDate not supplied

Sternocleidomastoid pseudotumor of infants and congenital muscular torticollis: fine-structure research.

Fifty cases, 16 with sternocleidomastoid pseudotumor of infants (SCMPOI) and 34 with congenital muscular torticollis (CMT), were investigated by light and electron microscopy. The ultrastructure of the pseudotumor revealed that there were myoblasts, fibroblasts, myofibroblasts, and mesenchyme-like cells, which consisted of fibrous tissue and were regarded as fibroblasts only in the literature. The myoblasts showed the various stages of differentiation and degeneration. For those cases without mass, the collagen fibrils and fibrocytes were often arranged in tight parallel bundles in which some muscles showed normal structure and some with decreased myofibrillae. The mesenchyme-like cells and myoblasts found in the pseudotumor may be the key point to its pathologic characteristics.

Child↗
PubMedDate not supplied

A panel of monoclonal antibodies against human sperm.

To help identify and characterize antigens involved in sperm functions and immune infertility, monoclonal antibodies (mAbs) were raised against human sperm antigens. The immunoglobulin G (IgG) fraction of serum from a male donor with a spontaneous high titer of IgG-positive antisperm reactivity (as determined by immunobead binding) was purified by ammonium sulfate precipitation. This IgG preparation was coupled to Sepharose 4B and was used for immunoaffinity purification of antigens from a detergent-solubilized extract of pooled normal human sperm. The affinity-purified antigens were used to immunize female mice, and the resultant spleen cells were fused with SP 2/0 mouse myeloma cells to generate hybridomas. A single-step semisolid methylcellulose method was used to isolate hybridomas for the selection of positive clones, which were determined by enzyme-linked immunosorbent assay. Thirty-two positive hybridoma lines were selected for immunolocalization and cross-reactivity studies using an avidin-biotin complex assay. Distinctive staining patterns and distribution of sperm antigens were observed for 10 mAbs. Among them, the cross-reactivity with human lymphocytes was not observed for four mAbs.

Adolescent↗
PubMedDate not supplied

Microbial limits reviewed: the basis for unique Australian regulatory requirements for microbial quality of non-sterile pharmaceuticals.

The need to retain Australian regulatory requirements for non-sterile pharmaceutical products has been questioned following publication of guideline limits in the 1996 Addendum to the British Pharmacopoeia (BP). The Therapeutic Goods Administration (TGA) contends that, in some respects, the BP limits, formulated by the European Pharmacopoeial Commission, do not provide for adequate patient safety. The case for retention of TGA guidelines is based on laboratory investigation into the microbial quality of product groups on the Australian market, and an assessment of the risk to patients of microbial contamination in pharmaceutical products which are not manufactured as sterile.

Australia↗