Cobalt-Protoporphyrin treatment renders islets tolerant to interleukin-1 beta suppression

This study examined whether treating donor mice with a single dose of cobalt protoporphyrin (CoPP) induced heme oxygenase-1 (HO-1) and protected islet cells from interleukin-1 beta (IL-1 beta) suppression. Islets were isolated from mice receiving a single dose of either CoPP (20 mg/kg of body weight, CoPP islets) or isotonic NaCl solution vehicle (control islets), 24 hours before isolation. Glucose-stimulated insulin secretion (GSIS) and insulin content (IC) of the islets were determined following incubation in the presence versus absence of murine IL-1 beta for 21 or 65 hours. The HO-1 protein level of CoPP-induced islets, as determined by an enzyme immunoassay, was significantly higher than that of control islets at 12 hours (P <.01) and 30 hours (P <.05), and returned to basal levels at 56 hours (P = NS). Following a 21-hour incubation with IL-1 beta, CoPP islets secreted significantly more insulin upon glucose stimulation and preserved significantly more IC than control islets. After 65-hour incubation with IL-1 beta, CoPP islets secreted significantly less insulin upon glucose stimulation than control islets and preserved significantly less IC compared to islets incubated without IL-1 beta. In conclusion, treatment with cobalt-protoporphyrin to induce heme oxygenase-1 protects islets against the suppressive effects of IL-1 beta.

Cobalt-protoporphyrin treatment enhances murine isoislets engraftment

To study the effect of treatment with cobalt-protoporphyrin (CoPP) for the induction of the heme oxygenase-1 (HO-1) enzyme on islet engraftment donor mice received either a single intraperitoneal injection of CoPP (20 mg/kg body weight) 1 day prior to islet isolation or this injection plus a 9 day posttransplantation course of Copp. After a single injection of CoPP, the CoPP-induced islets contained higher HO-1 proteins than did the normal islets both at 12 (5.3 +/- 1.5 vs 0.1 +/- 0.1 ng/mg protein, P < .01) and at 30 hours (6.8 +/- 2.1 vs 0.4 +/- 0.3 ng/mg protein, P < .05), but not at 56 hours (1.9 +/- 0.8 vs 1.6 +/- 0.8 ng/mg protein, P > .05). In contrast, diabetic mice that received 75 CoPP-induced islets and a 9-day CoPP injection course posttransplantation showed better improvement in blood glucose levels and body weights than did the mice that only received CoPP-induced islets. Mice of both CoPP-treated groups displayed better improvement in glycemic control than mice that received control islets. At 8 weeks after transplantation, the insulin content of grafts from both CoPP groups was significantly higher than that in the control group. In conclusion, CoPP treatment for the induction of HO-1 enhances engraftment of islets in a syngeneic murine transplantation model.

Adenovirus hexon T-cell epitope is recognized by most adults and is restricted by HLA DP4, the most common class II allele

The immunogenicity of adenovirus (Ad) vectors is enhanced by virus-specific memory immune responses present in most individuals as a result of past exposure to these ubiquitous pathogens. We previously identified the first human T-cell epitope from the major capsid protein hexon, H910-924, and found that it is highly conserved among different Ad serotypes. Memory/effector T-cell responses to H910-924 were detected in 14 of 18 (78%) healthy adults by an interferon-gamma ELISPOT assay. Hexon peptide-specific CD4 T-cell lines were generated from three HLA-typed donors and analyzed using a panel of HLA homozygous B-cell lines and monoclonal antibodies to HLA class II loci. These studies reveal that the hexon epitope is restricted by HLA DP4, a class II allele present in 75% of the population. Analysis of overlapping peptides and peptides with single residue mutations identified a HLA DP4-binding motif. Additionally, antibodies to the hexon peptide were detected in all donor sera by dot blot assay and ELISA. Therefore, most individuals exhibit both memory B- and T-cell responses to this highly conserved epitope on hexon, an obligate component of all Ad vectors, including 'gutted' vectors. These data suggest that current strategies for the use of Ad gene therapy vectors will not evade memory immune responses to Ad.

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.

Transforming growth factor beta 1 dysregulation in a human oral carcinoma tumour progression model

A human oral tumour progression model was established that consists of normal epithelial cells and three cell lines representing stages from dysplastic to metastatic cells. To investigate the impact of exogenous transforming growth factor-beta 1 on this model system, we analysed the responsiveness of those cells to transforming growth factor-beta 1 and explored the potential mechanism underlying the transforming growth factor-beta 1 activity. We found that the growth of all cell types, regardless of their stage of tumour progression, is inhibited by transforming growth factor-beta 1, although to different degrees. Transforming growth factor-beta 1 induced the expression of cyclin-dependent kinase inhibitors p15(INK4B), p21WAF1/(CIP1) and p27(KIP1). In contrast, transforming growth factor-beta 1 was found to stimulate the invasive potential of one cell type that represents the most advanced stage of tumour phenotype, suggesting that the impact of transforming growth factor-beta 1 on functional features of tumour cells other than cellular proliferation may play a significant role in the process of oral tumour progression.

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.

Chemopreventive effects of green tea polyphenols correlate with reversible induction of p57 expression

Green tea polyphenols are known to induce apoptosis in certain types of tumor cells. However, the mechanism(s) that enables normal cells to evade the apoptotic effect is still not understood. In this study, Western blot analysis combined with cycloheximide treatment was used to examine the effects of green tea polyphenols on the expression levels of p57, a cyclin-dependent kinase and apoptosis inhibitor, in normal human keratinocytes and in the oral carcinoma cell lines SCC25 and OSC2. The results showed that the most potent green tea polyphenol, (-)-epigallocatechin-3-gallate (EGCG), induced p57 in normal keratinocytes in a dosage- and time-dependent manner, while the levels of p57 protein in oral carcinoma cells were unaltered. The differential response in p57 induction was consistent with the apoptosis status detected by annexin V assay. The data suggest that the chemopreventive effects of green tea polyphenols may involve p57-mediated cell cycle regulation in normal epithelial cells.

A sperm ion channel required for sperm motility and male fertility

Calcium and cyclic nucleotides have crucial roles in mammalian fertilization, but the molecules comprising the Ca2+-permeation pathway in sperm motility are poorly understood. Here we describe a putative sperm cation channel, CatSper, whose amino-acid sequence most closely resembles a single, six-transmembrane-spanning repeat of the voltage-dependent Ca2+-channel four-repeat structure. CatSper is located specifically in the principal piece of the sperm tail. Targeted disruption of the gene results in male sterility in otherwise normal mice. Sperm motility is decreased markedly in CatSper-/- mice, and CatSper-/- sperm are unable to fertilize intact eggs. In addition, the cyclic-AMP-induced Ca2+ influx is abolished in the sperm of mutant mice. CatSper is thus vital to cAMP-mediated Ca2+ influx in sperm, sperm motility and fertilization. CatSper represents an excellent target for non-hormonal contraceptives for both men and women.

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.

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.