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Biomedical subjects

S Hsu

Publications and source records attributed to S Hsu.

At least 73 records · Page 4Linked to original sources
PubMed2000

Computer palms.

We describe a new occupation-related skin finding in 2 computer programmers and discuss its characteristics and causes.

Adult↗
PubMed2000

Calciphylaxis.

Calciphylaxis is a rare, life-threatening condition of widespread metastatic calcification most commonly seen in the setting of end-stage renal disease. The etiology of calciphylaxis is not well described, though there are several hypotheses. Cutaneous lesions are characteristically found on the abdomen, buttocks, or thighs as reticulated, painful, purple plaques that often undergo ulceration and may serve as a portal of entry for potentially life-threatening infectious agents. Histology reveals medial calcification with intimal proliferation involving small vessels in the subcutaneous fat, associated with a lymphohistiocytic infiltrate of the affected lobules. Treatment, including phosphate binders and parathyroidectomy, is not universally effective. We present one case of calciphylaxis and discuss the clinical features, pathophysiology, histology, and treatment of the condition.

Adult↗
PubMed2000

Maintaining updated DNA-based HLA assignments in the National Marrow Donor Program Bone Marrow Registry.

The National Marrow Donor Program (NMDP) has instituted an approach to address the impact of new alleles on the DNA-based HLA assignments obtained during volunteer donor typing. This approach was applied to the DRB typing results from 371,187 donors received from 14 laboratories in 1999. Samples were tested with a standardized set of sequence specific oligonucleotide reagents and the positive and negative hybridization results transmitted electronically to the NMDP. A software program interpreted the primary data into HLA assignments and rejected assignments which did not produce a result at the specified level of resolution. Comparison of the HLA assignments derived by the NMDP software to the assignments made by the laboratories using several local software prograins showed 90.5% of the assignments to be identical. Differences in assignments were explained by varying levels of typing resolution, variation in the inclusion of the second expressed DRB loci, disparity arising when alternative assignments were summarized, and failure to submit correct information. When the primary data collected in 1999 were interpreted into HLA assignments using the set of alleles defined in July 2000, 74% of the HLA-DRB assignments were altered by the description of new alleles, justifying the development of this software.

Base Sequence↗
PubMed1999

Two roads diverged: interferon alpha/beta- and interleukin 12-mediated pathways in promoting T cell interferon gamma responses during viral infection.

Viral infections induce CD8 T cell expansion and interferon (IFN)-gamma production for defense, but the innate cytokines shaping these responses have not been identified. Although interleukin (IL)-12 has the potential to contribute, IL-12-dependent T cell IFN-gamma has not been detected during viral infections. Moreover, certain viruses fail to induce IL-12, and elicit high levels of IFN-alpha/beta to negatively regulate it. The endogenous factors promoting virus-induced T cell IFN-gamma production were defined in studies evaluating CD8 T cell responses during lymphocytic choriomeningitis virus infections of mice. Two divergent supporting pathways were characterized. Under normal conditions of infections, the CD8 T cell IFN-gamma response was dependent on endogenous IFN-alpha/beta effects, but was IL-12 independent. In contrast, in the absence of IFN-alpha/beta functions, an IL-12 response was revealed and substituted an alternative pathway to IFN-gamma. IFN-alpha/beta-mediated effects resulted in enhanced, but the alternative pathway also promoted, resistance to infection. These observations define uniquely important IFN-alpha/beta-controlled pathways shaping T cell responses during viral infections, and demonstrate plasticity of immune responses in accessing divergent innate mechanisms to achieve similar ultimate goals.

Animals↗
PubMed1999

Inhibitory effects of combinations of HER-2/neu antibody and chemotherapeutic agents used for treatment of human breast cancers.

Previous studies have demonstrated a synergistic interaction between rhuMAb HER2 and the cytotoxic drug cisplatin in human breast and ovarian cancer cells. To define the nature of the interaction between rhuMAb HER2 and other classes of cytotoxic drugs, we applied multiple drug effect/combination index (CI) isobologram analysis to a variety of chemotherapeutic drug/rhuMAb HER2 combinations in vitro. Synergistic interactions at clinically relevant drug concentrations were observed for rhuMAb HER2 in combination with cisplatin (CI=0.48, P=0.003), thiotepa (CI=0.67, P=0.0008), and etoposide (CI=0.54, P=0.0003). Additive cytotoxic effects were observed with rhuMAb HER2 plus doxorubicin (CI=1.16, P=0.13), paclitaxel (CI=0.91, P=0.21), methotrexate (CI=1.15, P=0.28), and vinblastine (CI=1.09, P=0.26). One drug, 5-fluorouracil, was found to be antagonistic with rhuMAb HER2 in vitro (CI=2.87, P=0.0001). In vivo drug/rhuMAb HER2 studies were conducted with HER-2/neu-transfected, MCF7 human breast cancer xenografts in athymic mice. Combinations of rhuMAb HER2 plus cyclophosphamide, doxorubicin, paclitaxel, methotrexate, etoposide, and vinblastine in vivo resulted in a significant reduction in xenograft volume compared to chemotherapy alone (P<0.05). Xenografts treated with rhuMAb HER2 plus 5-fluorouracil were not significantly different from 5-fluorouracil alone controls consistent with the subadditive effects observed with this combination in vitro. The synergistic interaction of rhuMAb HER2 with alkylating agents, platinum analogs and topoisomerase II inhibitors, as well as the additive interaction with taxanes, anthracyclines and some antimetabolites in HER-2/neu-overexpressing breast cancer cells demonstrates that these are rational combinations to test in human clinical trials.

Adenocarcinoma↗
PubMed1999

Localized primary cutaneous Mycobacterium kansasii infection in an immunocompromised patient.

Mycobacterium Kansasii is a rare primary cutaneous pathogen, most commonly affecting persons exposed to contaminated water, particularly after local trauma. Most patients who present with localized primary cutaneous M kansasii infection are immunocompetent, whereas the majority of patients with disseminated or pulmonary infection are immunocompromised. We describe a primary cutaneous M kansasii infection in an iatrogenically immunosuppressed patient.

Aged↗
PubMed1998

Phosphodiesterase activity in intrapulmonary arteries and veins of perinatal lambs.

The transition from fetal to newborn life is marked by a reduction in pulmonary vascular tone mediated by the intracellular second messengers, cGMP and cAMP. We have compared the rates of phosphodiesterase (PDE)-catalyzed hydrolysis of cGMP and cAMP in intrapulmonary vessels of fetal (146 +/- 2 days gestation) and newborn (3-7-day-old) lambs, each n = 6. Lung vessels of second to sixth generations were dissected and cytosol was prepared by differential centrifugation. PDE activity in cytosol was determined by radiometric assay of the hydrolysis of exogenous nucleotides at 30 degrees C for 10 min. Rates of hydrolysis (pmol/min/mg protein) of cGMP were 225 +/- 38 in fetal arteries and different from 151 +/- 7 in veins. In newborn vessels, the rates were 155 +/- 49 and 63 +/- 13 in arteries and veins, respectively. Rates of cAMP hydrolysis by the fetus were 80 +/- 11 in arteries and 45 +/- 16 veins. In newborn lambs the rates were 69 +/- 10 in arteries and different from 18 +/- 4 in veins. Inhibition of PDE activity by zaprinast, a cGMP-specific PDE inhibitor, and rolipram, a cAMP-specific PDE inhibitor, was more in veins of fetal and newborn lambs. Our data show that rates of hydrolysis of the cyclic nucleotides were faster in fetal vessels than in the newborn. We speculate that this would result in a greater accumulation of the cyclic nucleotides in newborn vessels, particularly the veins, and therefore endow the veins with less vascular tone.

Animals↗
PubMed1998

Spores and mycelia in cutaneous chromomycosis.

In 2 cases of cutaneous chromomycosis, potassium hydroxide preparations of lesional crust/scale easily revealed characteristic Medlar bodies. However, in both instances mycelia were also demonstrated. This contradicts the prevailing belief that concomitant spores and mycelia are found only in cerebral chromomycosis.

Biopsy↗
PubMed1998

Rapid, automated assay for progesterone on the Abbott AxSYM analyzer.

We describe an automated assay for progesterone (P4) in human serum and plasma with the Abbott AxSYM random-access immunoassay analyzer. In this one-step competitive assay, P4 immobilized onto latex microparticles competes with sample P4 for binding to a conjugate of alkaline phosphatase (AP) and anti-P4 antibody. Total CVs ranged from 3.4% to 8.2% in multiple precision studies conducted according to the 20-day NCCLS EP5-T protocol. The detection limit (zero calibrator + 2 SD) was 0.10 microg/L across 36 experiments. Values for diluted samples were 83-116% of expected. Recovery of P4 added to serum specimens was 92-115%. Cross-reactivities with 43 natural and synthetic steroids were 0-6.3%. No significant interference was detected from bilirubin, protein, erythrocytes, hemoglobin, triglycerides, or cholesterol. In a multisite correlation study, AxSYM P4 results compared well with results from a commercial RIA method (n = 1156; r = 0.976; slope = 1.03; y-intercept = 0.04). Assay throughput is >80 tests per hour in batch mode, 60 tests per hour with mixed load list configurations.

Autoanalysis↗