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S Hsu

Publications and source records attributed to S Hsu.

At least 37 records · Page 2Linked to original sources
PubMed2001

Solution structure of the tumor necrosis factor receptor-1 death domain.

Tumor necrosis factor receptor-1 death domain (TNFR-1 DD) is the intracellular functional domain responsible for the receptor signaling activities. The solution structure of the R347K mutant of TNFR-1 DD was solved by NMR spectroscopy. A total of 20 structures were calculated by means of hybrid distance geometry-simulated annealing using a total of 1167 distance constraints and 117 torsion angle constraints. The atomic rms distribution about the mean coordinate positions for the 20 structures for residues composing the secondary structure region is 0.40 A for the backbone atoms and 1.09 A for all atoms. The structure consists of six antiparallel alpha-helices arranged in a similar fashion to the other members of the death domain superfamily. The secondary structure and three-dimensional structure of R347K TNFR1-DD are very similar to the secondary structure and deduced topology of the R347A TNFR1-DD mutant. Mutagenesis studies identified critical residues located in alpha2 and part of alpha3 and alpha4 that are crucial for self-interaction and interaction with TRADD. Structural superposition with previously solved proteins in the death domain superfamily reveals that the major differences between the structures reside in alpha2, alpha3, and alpha4. Interestingly, these regions correspond to the binding sites of TNFR1-DD, providing a structural basis for the specificity of death domain interactions and its subsequent signaling event.

Amino Acid Sequence↗
PubMed2001

Differential diagnosis of annular lesions.

Although most annular lesions will be typical of a dermatophytosis, physicians must consider other possible diagnoses. Tinea corporis can often be diagnosed on the basis of a positive potassium hydroxide examination. Topical and systemic antifungals are usually curative. Pityriasis rosea is characterized by small, fawn-colored lesions distributed along skin cleavage lines. Treatment is symptomatic. Granuloma annulare is characterized by nonscaly, annular plaques with indurated borders, typically on the extremities. One half of cases resolve spontaneously within two years. Sarcoidosis can present as annular, indurated plaques similar in appearance to the lesions of granuloma annulare. Diagnosis is based on histopathology and the involvement of other organ systems. Hansen's disease can mimic tinea corporis by presenting as one or more annular, sometimes scaly, plaques. Urticaria may affect 10 to 20 percent of the population. The annular plaques lack scale and are evanescent. Subacute cutaneous lupus erythematosus can present in an annular form on sun-exposed surfaces or in a papulosquamous form. Erythema annulare centrifugum typically presents as annular patches with trailing scale inside erythematous borders.

Antifungal Agents↗
PubMed2001

Complex HLA-DR and -DQ interactions confer risk of narcolepsy-cataplexy in three ethnic groups.

Human narcolepsy-cataplexy, a sleep disorder associated with a centrally mediated hypocretin (orexin) deficiency, is tightly associated with HLA-DQB1*0602. Few studies have investigated the influence that additional HLA class II alleles have on susceptibility to this disease. In this work, 1,087 control subjects and 420 narcoleptic subjects with cataplexy, from three ethnic groups, were HLA typed, and the effects of HLA-DRB1, -DQA1, and -DQB1 were analyzed. As reported elsewhere, almost all narcoleptic subjects were positive for both HLA-DQA1*0102 and -DQB1*0602. A strong predisposing effect was observed in DQB1*0602 homozygotes, across all ethnic groups. Relative risks for narcolepsy were next calculated for heterozygous DQB1*0602/other HLA class II allelic combinations. Nine HLA class II alleles carried in trans with DQB1*0602 were found to influence disease predisposition. Significantly higher relative risks were observed for heterozygote combinations including DQB1*0301, DQA1*06, DRB1*04, DRB1*08, DRB1*11, and DRB1*12. Three alleles-DQB1*0601, DQB1*0501, and DQA1*01 (non-DQA1*0102)-were found to be protective. The genetic contribution of HLA-DQ to narcolepsy susceptibility was also estimated by use of lambda statistics. Results indicate that complex HLA-DR and -DQ interactions contribute to the genetic predisposition to human narcolepsy but that additional susceptibility loci are also most likely involved. Together with the recent hypocretin discoveries, these findings are consistent with an immunologically mediated destruction of hypocretin-containing cells in human narcolepsy-cataplexy.

Black or African American↗
PubMed2001

Validation of DNA-based HLA-A and HLA-B testing of volunteers for a bone marrow registry through parallel testing with serology.

A total of 42,160 individuals were typed for HLA-A and HLA-B by both serology and PCR-based typing. The HLA assignments included all of the known serological equivalents. The majority of the individuals (99.9%) were from U.S. minority population groups. The serologic typing was performed between 1993 and 1997 at the time of recruitment for the National Bone Marrow Program (NMDP) registry. The polymerase chain reaction (PCR)-based typing was carried out in two phases. In phase I, DNA typing was performed by PCR using sequence-specific oligonucleotide probes (PCR-SSOP) or PCR using sequence-specific primers (PCR-SSP) without knowledge of the serologic assignments. Discrepancies were identified between the serologic and DNA assignments in 24% of the volunteers (8% of volunteers differed for only HLA-A assignments, 13% for HLA-B, and 3% for both HLA-A and -B) and a potential explanation was assigned each discrepant serology/DNA pair. In phase II, a random sampling scheme was used to select a statistically significant number of individuals for repeat DNA typing from each of these categories. The categories included antigens missed by serology, nonexpressed (null) alleles, PCR amplification failures, misassignment of antigens and nomenclature issues. Only a single individual was found to carry a null allele. DNA-based testing correctly typed nearly 99% of the donors at HLA-A, more than 98% at HLA-B, and more than 97% at both HLA-A and -B validating this methodology for registry typing.

Bone Marrow Examination↗
PubMed2001

Becker's melanosis in a woman.

Becker's melanosis is a relatively common, benign hamartoma, which is usually characterized by a hyperpigmented, hypertrichotic patch on the upper trunk or proximal upper extremities of males, with its onset during the peripubertal years. Commonly, there is an associated smooth muscle hamartoma on histology. We present a woman with a Becker's melanosis on the leg without hypertrichosis. We believe that the spectrum of Becker's nevus is greater than commonly thought and that cases similar to ours are not rare, but have been diagnosed as other conditions.

Adult↗
PubMed2001

Multicentric reticulohistiocytosis with neurofibroma-like nodules.

We describe a patient with multicentric reticulohistiocytosis (MR), who presented with 2 different clinical types of lesions. Some were characteristic for MR in that they were deeply set, small, firm papules. Many others were larger, soft, and even sessile, like neurofibromas. Histopathologic features of both types of lesions revealed MR. To our knowledge, this is the first report of lesions of MR mimicking neurofibromas.

Adrenal Cortex Hormones↗
PubMed2001

Acantholytic dermatosis of the vulvocrural area.

Acantholytic dermatosis of the vulvocrural area is a rare skin disorder characterized by solitary or multiple skin-colored to white, smooth papules or plaques. Histopathological features of both Hailey-Hailey disease and Darler's disease are present. There is acantholysis, which may involve the full thickness of the epidermis, and dyskeratosis with corps ronds and grains. There may be marked hyperkeratosis and focal parakeratosis. We report a case of this rare disease and discuss its differential diagnosis and treatment.

Acantholysis↗
PubMed2001

Erythema elevatum diutinum mimicking extensive keloids; quiz 386.

GOAL: To describe a case of erythema elevatum diutinum (EED) that clinically mimicked extensive keloids. OBJECTIVES: Upon completion of this activity, dermatologists and general practitioners should be able to: 1. Describe the clinical presentation and lesion appearance in EED. 2. Discuss the electron microscopic and laboratory findings of EED. 3. Outline treatment options for EED. CME: This article has been peer reviewed and approved by Michael Fisher, MD, Professor of Medicine, Albert Einstein College of Medicine. REVIEW DATE: April 2001. This activity has been planned and implemented in accordance with the Essentials and Standards of the Accreditation Council for Continuing Medical Education through the joint sponsorship of Albert Einstein College of Medicine and Quadrant HealthCom, Inc. The Albert Einstein College of Medicine is accredited by the ACCME to provide continuing medical education for physicians. Albert Einstein College of Medicine designates this educational activity for a maximum of 1.0 hour in category 1 credit toward the AMA Physician's Recognition Award. Each physician should claim only those hours of credit that he/she actually spent in the educational activity. This activity has been planned and produced in accordance with ACCME Essentials.

Dapsone↗