Diversity of HLA-DQA1 gene in the Korean population.

Genotype of the human leukocyte antigen (HLA)-DQA1 locus was analyzed in Koreans (n= 467) using the 14th International Workshop protocol established to characterize the sequences of exons 1-4 of the gene. Unexpectedly, it appeared that the DQA1 (19 alleles) was more diverse than DQB1 (15 alleles) in the study population. DQA1*010201, DQA1*0303, DQA1*0103, and DQA1*0302 appeared to be major alleles exhibiting more than 10%. Among six allele groups, DQA1*01-*06, DQA1*01 showed highest diversity exhibiting seven different alleles. Analysis using maximum likelihood method showed numerous multi-locus HLA haplotypes. High relative linkage disequilibrium values (RLD) of the two-locus haplotypes and exclusive association of a specific DQA1 allele with a specific DRB1 and/or DQB1 alleles suggested tight linkage of DQA1 to DRB1 and DQB1. In HLA-matching process for hematopoietic stem cell transplantation, however, DQA1 typing would be informative for individuals carrying specific DRB1 allele (DRB1*0802, DRB1*1201, or DRB1*1403) that could be associated with multiple DQA1 alleles in the study population. Information obtained in this study will be useful in medical and forensic areas as well as in anthropology.

Spatially localized generation of nucleotide sequence-specific DNA damage.

Psoralens linked to triplex-forming oligonucleotides (psoTFOs) have been used in conjunction with laser-induced two-photon excitation (TPE) to damage a specific DNA target sequence. To demonstrate that TPE can initiate photochemistry resulting in psoralen-DNA photoadducts, target DNA sequences were incubated with psoTFOs to form triple-helical complexes and then irradiated in liquid solution with pulsed 765-nm laser light, which is half the quantum energy required for conventional one-photon excitation, as used in psoralen + UV A radiation (320-400 nm) therapy. Target DNA acquired strand-specific psoralen monoadducts in a light dose-dependent fashion. To localize DNA damage in a model tissue-like medium, a DNA-psoTFO mixture was prepared in a polyacrylamide gel and then irradiated with a converging laser beam targeting the rear of the gel. The highest number of photoadducts formed at the rear while relatively sparing DNA at the front of the gel, demonstrating spatial localization of sequence-specific DNA damage by TPE. To assess whether TPE treatment could be extended to cells without significant toxicity, cultured monolayers of normal human dermal fibroblasts were incubated with tritium-labeled psoralen without TFO to maximize detectable damage and irradiated by TPE. DNA from irradiated cells treated with psoralen exhibited a 4- to 7-fold increase in tritium activity relative to untreated controls. Functional survival assays indicated that the psoralen-TPE treatment was not toxic to cells. These results demonstrate that DNA damage can be simultaneously manipulated at the nucleotide level and in three dimensions. This approach for targeting photochemical DNA damage may have photochemotherapeutic applications in skin and other optically accessible tissues.

Transverse myelitis in a patient with long-standing ankylosing spondylitis.

Ankylosing spondylitis is reported to involve not only the joints but other organs as well. Among these extra-articular involvements, uncommon complications associated with nervous system such as single root lesions, compression of the myelum and cauda equina syndrome have also been documented. Here we present a patient with long-standing ankylosing spondylitis who developed spastic paraparesis. Extensive study to find the cause of a spastic paraparesis failed and therefore led to the conclusion that this patient was suffering from transverse myelitis. Similar reports in the past have been attributed to an association with multiple sclerosis; however, we suggest that the findings support the diagnosis of a rare complication of ankylosing spondylitis with an unknown etiology.

Incidence and characterization of Listeria spp. from foods available in Korea.

A total of 410 domestic Korean food samples were analyzed for the presence of Listeria spp. by the conventional U.S. Department of Agriculture protocol, and presumptive strains were identified by morphological, cultural and biochemical tests according to Bergey's manual and confirmed by API-Listeria kit. Among the total 410 food samples, 46 samples (11.2%) were found to be contaminated with Listeria species. Among the 46 strains of Listeria spp. isolates, 8 strains (17.42%) for Listeria monocytogenes, 3 strains (6.5%) for Listeria seeligeri, 33 strains (71.7%) for Listeria innocua, and 2 strains (4.4%) for Listeria welshimeri were identified, respectively. Also, only beef, chicken, pork, frozen foods, and sausage were contaminated with L. monocytogenes, and the other products were free of L. monocytogenes. Of 46 Listeria spp. isolates, L. innocua (71.7%) was the most predominantly isolated in a variety of foods compared to other Listeria spp. An in vitro virulence assay for Listeria spp. using myeloma and hybridoma cells from murine and human sources was performed. The result showed that only L. monocytogenes killed approximately 95 to 100% hybridoma cells after 6 h and the other Listeria species, such as L. innocua, L. seeligeri, and L. welshimeri strains had about 0 to 10% lethal effect on hybridoma cells. Also, an antibiotic susceptibility test showed that Listeria spp. isolates were very susceptible to the antibiotics tested, except for nalidixic acid. Also, serotyping results showed 75% of L. monocytogenes isolates from beef, chicken, and frozen pizza belonged to serotype 1 and 25% from sausage were type 4.

A phase II study of VP-16-fosfamide-cisplatin combination chemotherapy plus early concurrent thoracic irradiation for previously untreated limited small cell lung cancer.

BACKGROUND: At present the addition of thoracic irradiation to combination chemotherapy is a standard treatment for limited staged small cell lung cancer. However, there is still controversy about the optimum timing of chest irradiation. We conducted a phase II study of etoposide (VP-16)-ifosfamide-cisplatin (VIP) combination chemotherapy plus early concurrent thoracic irradiation for the patients with previously untreated limited small cell lung cancer in order to assess if the treatment modality could improve the response rate and the toxicity. METHODS: Forty-four patients with limited small cell lung cancer were treated with etoposide-ifosfamide-cisplatin and concurrent thoracic irradiation. Combination chemotherapy consisted of etoposide 100 mg/m2 (on days 1-3), ifosfamide 1000 mg/m2 (on days 1 and 2) and cisplatin 100 mg/m2 (on day 1). Concurrent thoracic irradiation consisted of a total of 4000 cGy over 4 weeks starting on the first day of the first chemotherapy. All patients who showed a complete response were given prophylactic cranial irradiation for 2.5 weeks. RESULTS: Forty-four of the 49 patients who entered the study from May 1994 to August 1998 were evaluable. The median age was 59 years and 40 patients had a performance status of 0 or 1. The median survival time was 22.5 months. Twenty-eight patients (62%) showed a complete response and 16 (38%) a partial response. Twenty-four patients (54%) developed grade 3 or 4 neutropenia; there was a 9% RTOG score 3 or 4 esophagitis. CONCLUSION: VIP combination chemotherapy and early concurrent thoracic irradiation for patients with limited stage small cell lung cancer revealed excellent antitumor response with tolerable toxicity.

Triple helix-forming oligonucleotides target psoralen adducts to specific chromosomal sequences in human cells.

The ability to target photochemical adducts to specific genomic DNA sequences in cells is useful for studying DNA repair and mutagenesis in intact cells, and also as a potential mode of gene-specific therapy. Triple helix-forming DNA oligonucleotides linked to psoralen (psoTFOs) were designed to deliver UVA-induced psoralen photoadducts to two distinct sequences within the human interstitial collagenase gene. A primer extension assay demonstrated that the appropriate psoTFO selectively damages a collagenase cDNA target. Site-specific genomic psoTFO DNA adducts were detected by a single-strand ligation PCR assay. The adduct, formed at a single site by a psoTFO in purified genomic DNA, contrasted with the multiple sites that were damaged within the observed segment of the collagenase gene upon treatment with free psoralen and subsequent photoactivation. When treated with psoTFOs, both repair-deficient fibroblasts from xero- derma pigmentosum complementation group A and HT1080 fibrosarcoma cells exhibited site-specific DNA adducts following UVA irradiation. Addition of phorbol ester, a transcriptional activator of the collagenase gene, to xeroderma pigmentosum cells did not detectably alter the initial levels of damage produced by psoTFOs, suggesting that further stimulation of transcription neither improves accessibility of psoTFOs to their targets nor enhances removal of non-covalently bound psoTFOs.

Five cases of calciphylaxis and a review of the literature.

Calciphylaxis is a rare phenomenon of cutaneous necrosis that typically occurs in association with renal failure and has a poor prognosis. We report 5 new cases of calciphylaxis that illustrate the important clinical and histopathologic features of the disease. All patients had end-stage renal failure at the time that purpuric plaques and nodules were noted; these subsequently progressed to necrotic ulcers with eschars. All skin biopsy specimens showed varying degrees of calcification of the medial layer of blood vessel walls in the dermis and subcutaneous fat. Neither the product of serum calcium and phosphorus concentrations nor parathyroid hormone levels correlated temporally with the clinical observations in every case, emphasizing the importance of clinical-histopathologic correlation. Although certain features of calciphylaxis in humans resemble the animal model originally proposed, there are also some crucial differences. We review the pathogenesis, epidemiology, clinical and histopathologic features, and treatment of this disease.

A young boy with a large hemifacial plaque with histopathologic features of trichoepithelioma.

Trichoepitheliomas commonly appear as sporadic solitary lesions or, more rarely, as multiple lesions that are often dominantly inherited. We describe an 8-year-old boy with multiple facial papules that coalesced into a large plaque. This presentation of multiple trichoepitheliomas may represent an unusual type of nevus.

Monolaurin and acetic acid inactivation of Listeria monocytogenes attached to stainless steel.

Individual and combined antimicrobial effects of monolaurin and acetic acid on Listeria monocytogenes planktonic cells or stainless-steel-adherent cells were determined in order to evaluate cell viability during a 25-min exposure period at 25 degrees C. A 10(7)-colony-forming units (CFU)/ml population of planktonic cells was completely inactivated by the synergistic combination of 1% acetic acid with 50 or 100 microg/ml of monolaurin within 25 or 20 min, respectively. Either compound alone caused partial but incomplete inactivation within the same time periods. A population of 10(5) CFU/cm2 of 1-day adherent cells on stainless steel was completely inactivated within 25 min, but with the highest concentrations of the combined chemicals, i.e., 1% acetic acid and 100 microg/ml of monolaurin. The combined chemical treatment again synergistically produced greater inhibition. A 10(6)-CFU/cm2 population of 7-day adherent cells was not completely inactivated within 25 min of exposure, although counts did decline. The results demonstrate increased resistance of attached L. monocytogenes to acetic acid and monolaurin and show that resistance increased with culture age. Combinations of organic acids and monolaurin might be considered as sanitizers of food contact surfaces, but activities of such combinations are likely to be less than other commonly used sanitizers.

Molecular cloning and sequence analysis of the rat liver carnitine octanoyltransferase cDNA, its natural gene and the gene promoter.

The full-length cDNA and the natural gene for rat peroxisomal carnitine octanoyltransferase (COT) have been isolated and sequenced. The 2681 bp long cDNA contains an open reading frame for 613 amino acids, resulting in a protein with a deduced molecular weight of 70,301, and a C-terminal peroxisomal targeting sequence (Ala-His-Leu). The isolated COT cDNA has 51 bp of the 5' untranslated region (UTR), 791 bp of 3' UTR, two putative polyadenylation sites, and a poly(A19-23) tail. Screening of a rat genomic DNA library in the lambda phage with the COT cDNA probe resulted in the isolation of seven overlapping clones, together containing the complete COT gene with seventeen exons. All of the exon-intron boundary sequences conform to the GT-AG rule. The COT gene appears to spread over 40 to 60 kbp region of the rat genome. The transcription initiation site of the COT gene was determined through primer extension, and the promoter sequence up to the position -1140 was established. The promoter lacks the canonical TATA box and a promoter-reporter construct containing the sequence encompassing -1140 to +84 base positions and the firefly luciferase reporter cDNA yielded about 100-fold increase in promoter activity in transfected hepatoma cells. Some of the consensus sequences for putative cis elements present in the promoter sequence are: the two CCAAT motifs for CTF/NF1/CBP binding (at -284 and -93), two GC boxes for Sp1 binding (at -160 and -68), two AP2 sites (at -359 and -25), a half site (TGACCT) for the peroxisome proliferator activated receptor (PPAR) binding at -737 within a partial palindromic sequence region. Potential regulatory elements, such as several palindromes and repeat motifs for five different sequence segments, are also identified.

Inhibition of collagenase type I expression by psoralen antisense oligonucleotides in dermal fibroblasts.

Type I collagenase plays an important role in both tumor metastasis and the remodeling of connective tissue in normal human skin, during wound healing, for example, and may participate in the pathophysiology of some dermatological diseases such as skin cancer and a chronic blistering disease, recessive dystrophic epidermolysis bullosa. In an effort specifically to inhibit collagenase expression, we have designed phosphorothioate antisense oligonucleotides, linked at the 5' ends with photoreactive 4'-(hydroxyethoxymethyl)-4,5',8-trimethyl-psoralen (HMT), and directed them against the 5' end of the collagenase mRNA. Two antisense-HMT molecules targeting a region overlapping the initiation codon were compared. Only one contained the HMT moiety targeting a 5'TpA on its complementary sense strand, and we observed greater than 50-fold improvement on the cross-linking of this antisense oligonucleotide to its target sequence after ultraviolet A (UVA) irradiation. Likewise, sequence complementary to the 5'TpA target was also required to demonstrate specific inhibition of in vitro translation of collagenase mRNA. Tissue culture experiments, conducted by incubation of collagenase-specific antisense-HMT oligonucleotides with fibroblasts in monolayer or in 3-dimensional dermal equivalents, showed lowered collagenase levels 24 h after UVA irradiation as compared to controls. Initial screening of antisense oligomers for specific hybridization and photo-cross-linking is a useful step in the design of antisense oligonucleotides, and allowed us to design an HMT-linked antisense phosphorothioate oligonucleotide that specifically inhibits the expression of fibroblastic collagenase.