The Bloom's syndrome gene (BLM) plays a pivotal role in the maintenance of genomic stability in somatic cells. It encodes a DNA helicase (BLM) of the RecQ family, but the exact function of BLM remains elusive. To study this question, we have cloned the BLM homolog of the frog Xenopus laevis (xBLM) and have raised antibodies to it. Immunodepletion of xBLM from a Xenopus egg extract severely inhibits the replication of DNA in reconstituted nuclei. Moreover, the inhibition can be rescued by the addition of the recombinant xBLM protein. These results provide the first direct evidence that BLM plays an important role in DNA replication, suggesting that Bloom's syndrome may be the consequence of defective DNA replication.

Adenosine Triphosphatases↗

PubMed2000

Preliminary results of chemoradiation as a primary treatment for vulvar carcinoma.

PURPOSE: To assess the role of chemoradiation as a primary treatment for vulvar carcinoma. METHODS AND MATERIALS: Between December 1989 and August 1997, there were 14 patients with the diagnosis of squamous cell carcinoma of the vulva. Two patients were excluded from this study because of advanced stage at presentation. Key information about the remaining 12 patients was extracted from their charts. All patients had biopsy prior to treatment, and were treated with chemoradiation. Radiation was administered to the vulva only. Surgical biopsies from the vulva and inguinal nodal dissection were done 4-6 weeks after radiation treatment. All patients were followed for evaluation of response and clinical detection of recurrence. The period of follow-up ranged from 8 to 125 months. Mean follow-up period was 41 months. RESULTS: All 12 patients showed complete response to the treatment. Only 1 patient (8.3%) developed local recurrence at 3 months posttreatment. Another patient (8.3%) developed nodal recurrence at 30 months posttreatment. Both patients were salvaged by surgical treatment and remained disease free. The actuarial 5-year disease-free survival was 43%. The actuarial 3-year disease-free survival was 84%. The majority of patients developed mild-to-moderate complications due to chemoradiation. These were well tolerated and responded to medical treatment. None of the patients developed late complications to chemoradiation treatment. CONCLUSIONS: Chemoradiation is an effective primary treatment for vulvar carcinoma as shown by these successfully managed cases.

Aged↗

PubMed2000

CD8+ T cells are necessary for recognition of allelic, but not locus-mismatched or xeno-, HLA class I transplantation antigens.

Although HLA transgenic mice (HLA TgM) could provide a powerful approach to investigate human MHC-specific T cell responsiveness, the extent to which these molecules are recognized by the mouse immune system remains unclear. We established TgM expressing HLA class I alleles A2, B7, or B27 in their fully native form (HLAnat) or as hybrid molecules (HLAhyb) of the HLA alpha1/alpha2 domains linked to the H-2Kb alpha3, transmembrane, and cytoplasmic domains (i.e., to maintain possible species-specific interactions). Comparison of each as xeno- (i.e., by non-TgM) vs allo- (i.e., by TgM carrying an alternate HLA allele) transplantation Ags revealed the following: 1) Although HLAhyb molecules induced stronger xeno-CD8+ T cell responses in vitro, additional effector mechanisms must be active in vivo because HLAnat skin grafts were rejected faster by non-TgM; 2) gene knockout recipients showed that xenorejection of HLAnat and, unexpectedly, HLAhyb grafts doesn't depend on CD8+ or CD4+ T cells or B cells; 3) each HLAhyb strain developed tolerance to "self" but rejected allele- (-B27 vs -B7) and locus- (-B vs -A) mismatched grafts, the former requiring CD8+ T cells, the latter by CD8+ T cell-independent mechanisms. The finding that recognition of xeno-HLAhyb does not require CD8+ T cells while recognition of the identical molecule in a strictly allo context does, demonstrates an alpha1/alpha2 domain-dependent difference in effector mechanism(s). Furthermore, the CD8+ T cell-independence of locus-mismatched rejection suggests the degree of similarity between self and non-self alpha1/alpha2 determines the effector mechanism(s) activated. The HLA Tg model provides a unique approach to characterize these mechanisms and develop tolerance protocols in the context of human transplantation Ags.

Alleles↗

PubMed2000

Alendronate for the treatment of osteoporosis in men.

BACKGROUND: Despite its association with disability, death, and increased medical costs, osteoporosis in men has been relatively neglected as a subject of study. There have been no large, controlled trials of treatment in men. METHODS: In a two-year double-blind trial, we studied the effect of 10 mg of alendronate or placebo, given daily, on bone mineral density in 241 men (age, 31 to 87 years; mean, 63) with osteoporosis. Approximately one third had low serum free testosterone concentrations at base line; the rest had normal concentrations. Men with other secondary causes of osteoporosis were excluded. All the men received calcium and vitamin D supplements. The main outcome measures were the percent changes in lumbar-spine, hip, and total-body bone mineral density. RESULTS: The men who received alendronate had a mean (+/-SE) increase in bone mineral density of 7.1+/-0.3 percent at the lumbar spine, 2.5+/-0.4 percent at the femoral neck, and 2.0+/-0.2 percent for the total body (P<0.001 for all comparisons with base line). In contrast, men who received placebo had an increase in lumbar-spine bone mineral density of 1.8+/-0.5 percent (P<0.001 for the comparison with base line) and no significant changes in femoral-neck or total-body bone mineral density. The increase in bone mineral density in the alendronate group was greater than that in the placebo group at all measurement sites (P<0.001). The incidence of vertebral fractures was lower in the alendronate group than in the placebo group (0.8 percent vs. 7.1 percent, P=0.02). Men in the placebo group had a 2.4-mm decrease in height, as compared with a decrease of 0.6 mm in the alendronate group (P=0.02). Alendronate was generally well tolerated. CONCLUSIONS: In men with osteoporosis, alendronate significantly increases spine, hip, and total-body bone mineral density and helps prevent vertebral fractures and decreases in height.

Adult↗

PubMed2000

The mitochondrial genome of the stramenopile alga Chrysodidymus synuroideus. Complete sequence, gene content and genome organization.

This is the first report of a complete mitochondrial genome sequence from a photosynthetic member of the stramenopiles, the chrysophyte alga Chrysodidymus synuroideus. The circular-mapping mitochondrial DNA (mtDNA) of 34 119 bp contains 58 densely packed genes (all without introns) and five unique open reading frames (ORFs). Protein genes code for components of respiratory chain complexes, ATP synthase and the mitoribosome, as well as one product of unknown function, encoded in many other protist mtDNAs (YMF16). In addition to small and large subunit ribosomal RNAs, 23 tRNAs are mtDNA-encoded, permitting translation of all codons present in protein-coding genes except ACN (Thr) and CGN (Arg). The missing tRNAs are assumed to be imported from the cytosol. Comparison of the C.SYNUROIDEUS: mtDNA with that of other stramenopiles allowed us to draw conclusions about mitochondrial genome organization, expression and evolution. First, we provide evidence that mitochondrial ORFs code for highly derived, unrecognizable versions of ribosomal or respiratory genes otherwise 'missing' in a particular mtDNA. Secondly, the observed constraints in mitochondrial genome rearrangements suggest operon-based, co-ordinated expression of genes functioning in common biological processes. Finally, stramenopile mtDNAs reveal an unexpectedly low variability in genome size and gene complement, testifying to substantial differences in the tempo of mtDNA evolution between major eukaryotic lineages.

Algal Proteins↗

PubMed2000

The effect of stents on mucosal wound healing.

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Animals↗

PubMed2000

Ciprofibrate therapy improves endothelial function and reduces postprandial lipemia and oxidative stress in type 2 diabetes mellitus.

BACKGROUND: Exaggerated postprandial lipemia (PPL) is a factor in atherogenesis, involving endothelial dysfunction and enhanced oxidative stress. We examined the effect of ciprofibrate therapy on these parameters in type 2 diabetes mellitus. METHODS AND RESULTS: Twenty patients entered a 3-month, double-blind, placebo-controlled study. Each subject was studied fasting and after a fatty meal, at baseline, and after 3 months of treatment. Glucose and lipid profiles were measured over an 8-hour postprandial period. Endothelial function (flow-mediated endothelium-dependent vasodilatation [FMD]) and oxidative stress (electron paramagnetic resonance spectroscopy) were measured after fasting and 4 hours postprandially. At baseline, both groups exhibited similar PPL and deterioration in endothelial function. After ciprofibrate, fasting and postprandial FMD values were significantly higher (from 3.8+/-1. 8% and 1.8+/-1.3% to 4.8+/-1.1% and 3.4+/-1.1%; P<0.05). This was mirrored by a fall in fasting and postprandial triglycerides (3. 1+/-2.1 and 6.6+/-4.1 mmol/L to 1.5+/-0.8 and 2.8+/-1.3 mmol/L, P<0. 05). Fasting and postprandial HDL cholesterol was also elevated (0. 9+/-0.1 and 0.8+/-0.1 mmol/L and 1.2+/-0.2 and 1.2+/-0.1 mmol/L, P<0. 05). There were no changes in total or LDL cholesterol. Fasting and postprandial triglyceride enrichment of all lipoproteins was attenuated, with cholesterol depletion of VLDL and enrichment of HDL. There were similar postprandial increases in oxidative stress in both groups at baseline, which was significantly attenuated by ciprofibrate (0.3+/-0.6 versus 1.5+/-1.1 U, P<0.05). CONCLUSIONS: This study demonstrates that fibrate therapy improves fasting and postprandial endothelial function in type 2 diabetes. Attenuation of PPL and the associated oxidative stress, with increased HDL cholesterol levels, may be important.

Adult↗

PubMed2000

Sulfur mustard-induced skin burns in weanling swine evaluated clinically and histopathologically.

Histopathological indicators and clinical observations were used to evaluate wound severity, depth and degree of healing on days 2 and 8 for full-skin-thickness sulfur-mustard (HD)-induced burns in weanling swine. Six female weanling swine were exposed for 2 h to 400 microl of HD at each of six dose sites on the hairless abdominal skin. Biopsy samples (8 mm) were taken from the periphery and from the center of the wound on day 2, and the wound was excised on day 8. Histopathological indicators evaluated were epidermal necrosis, follicular necrosis, dermal necrosis, vascular necrosis, depth of injury, ulceration (loss of epidermis), granulation tissue response, neovascularization, re-epithelialization (hyperplasia) and completeness of healing. Wounds were more severe from anterior to posterior. Histopathological assessment of epidermal ulceration and necrosis of epidermis, dermis, basal epithelium, adnexal structures and subcutaneous tissue were useful indicators of wound development on day 2. Granulation tissue response (observed as early as day 8) and re-epithelialization were good indicators of wound healing. Clinical evaluations were performed on day 2 prior to and after debriding, and on study day 8. Clinical observations on study day 2 were for wound size and for exudation, erythema, edema, necrosis and eschar. Clinical observations on study day 8 were for the previous parameters and for re-epithelialization, granulation and infection. Wound size and severity increased from anterior to posterior position. Size, exudation and edema were useful indicators of wound development. These histological and clinical observation parameters will be used in future experiments to compare various treatments for HD-induced burns.

Animals↗

PubMed2000

Day 3 morphology is a poor predictor of blastocyst quality in extended culture.

OBJECTIVE: To determine how the quality of blastocysts formed on day 5/6 of extended culture compares with their morphology on day 3. DESIGN: Retrospective observational study of IVF laboratory records. SETTING: Private assisted reproduction clinic. PATIENT(S): 101 IVF cycles in which 5 to 25 embryos were produced. The average maternal age was 33.1 years. INTERVENTION(S): Embryos were individually cultured in vitro in sequential media for an extended time to enable use of blastocysts for fresh transfer or cryopreservation. MAIN OUTCOME MEASURE(S): Comparison of embryo quality for putative ET or cryopreservation on day 3 with quality of embryos used for actual ET and cryopreservation on day 5/6. RESULT(S): Of 1,263 cleaving embryos, 559 were judged to have been suitable for use on day 3; 355 would have been used for ET (average per ET, 3.5) and 204 would have been frozen (equivalent to 44% utilization). In actuality, 471 blastocysts were used on day 5/6, of which 234 were transferred (average per ET, 2.3), and 237 were frozen (equivalent to 37% utilization). Only 48% embryos that would have been chosen for ET and/or cryopreservation on day 3 were eventually used in such a manner at the blastocyst stage. Historically, the rate of viable pregnancy from day 3 transfers was 30.5% per transfer; this rate increased to 45% with routine day 5/6 transfers. CONCLUSION(S): Extended culture of human embryos seems to increase discrimination of potential embryonic viability. Criteria for embryo selection on day 3 seem to be inadequate. Extended in vitro culture may therefore be an effective means of optimizing IVF clinical success.

Adult↗