Three novel linear plasmids, pDHL1 (8.4 kb), pDHL2 (9.2 kb) and pDHL3 (15.0 kb), were discovered in the halophilic (salt-tolerant) yeast Debaryomyces hansenii. Exonuclease treatment indicated that all three plasmids were blocked at their 5' ends, presumably, by analogy with most other eukaryotic linear plasmids which involved protein attachment. The Debaryomyces plasmids were entirely cured simply by growing cells in normal culture medium, but were stably maintained in culture medium containing salts, sorbitol or glycerol at suitable concentrations. This suggested that the pDHL plasmids required an osmotic pressure for stable replication and maintenance. The Debaryomyces yeast secreted a killer toxin against various yeasts species. Toxin activity was demonstrated only in the presence of salts such as NaCl or KCl, but this killer phenotype was not associated with the pDHL plasmids. Analysis of the plasmid-curing pattern suggested that pDHL3 may play a key role in the replication of the Debaryomyces plasmids. Southern hybridization showed that an extensive homology exists between specific regions of pDHL1 and pDHL2, whereas pDHL3 is unique.

Blotting, Southern↗

PubMedDate not supplied

A prospective 5-year follow-up study on the behavioral disturbances of community-dwelling elderly people with Alzheimer disease.

The aim of the present study was to determine the longitudinal course of behavioral disturbances and to examine whether these disturbances are stage dependent during the course of Alzheimer disease (AD). One hundred seven community-dwelling patients with probable AD were assessed up to six times annually by using a validated and reliable rating scale, the Troublesome Behavior Scale, for assessing the frequencies of behavioral disturbances. The subjects were divided into three groups according to their baseline global function as assessed by the Clinical Dementia Rating (CDR; 1 = mild, 2 = moderate, 3 = severe). At the end of the 5-year observation period, 31 subjects were still active participants, 52 had died, 20 lived in institutions, and 4 had stopped participating. The patterns of their behavioral disturbance changes depended to a considerable extent on the baseline severity of the illness. The behavioral disturbance frequencies generally peaked at the CDR 2 stage and followed a downward trend thereafter. Considerable individual variations in the disturbance frequencies during the course of the illness were observed. Knowing the behavioral course of AD will enable clinicians to better counsel families and appraise the results of treatments for behavioral symptoms.

Aged↗

PubMedDate not supplied

DNA vaccine against hamster oral papillomavirus-associated oral cancer.

Previously we developed a carcinogenesis model involving the combination of 9,10-dimethyl-1,2-benzanthracene (DMBA) application with physical wounding of hamster lingual mucosa. The presence of a novel hamster oral papillomavirus (HOPV) was demonstrated and its genome sequenced. In the present study, this HOPV hamster model was used to test whether vaccination with the L1 gene could prevent the development of oral carcinoma. DNA plasmids encoding the L1 gene or the vector alone were injected intramuscularly into 20 vaccinated and 20 control hamsters, respectively. The lingual tips of the hamsters were painted with DMBA for 8 weeks. A portion of the lingual tips was excised, and the tips were then painted daily with DMBA until the animals were killed 13 days later. All control hamsters developed lingual carcinoma, whereas 12 of the L1-vaccinated hamsters showed no lesions. These results suggest that immunization with L1 DNA vaccines may prevent the development of papillomavirus-associated oral cancer.

9,10-Dimethyl-1,2-benzanthracene↗

PubMedDate not supplied

Enhanced natural killer cell activity in patients with pulmonary tuberculosis.

The natural killer (NK) cell activity of patients with pulmonary tuberculosis (TB) was studied using blood samples. The patients with pulmonary TB showed higher NK activity to 10 out of 12 NK-sensitive target cell lines than healthy subjects did. When NK activity was compared between active and inactive stages of the disease, the patients with active TB demonstrated higher NK activity than did patients with inactive TB. Furthermore, active patient displayed cytolysis to one out of 4 NK-resistant target cell lines. In study of NK cell cyotoxicity at single cell level, higher killing activity than binding activity to target cells was observed in patients at an active stage. Morphological and surface marker analysis of peripheral mononuclear cells showed an increase in CD16+ cells in patients with pulmonary TB. These results suggested that NK cell activity is augmented qualitatively and quantitatively in patients with pulmonary TB.

Adult↗

PubMedDate not supplied

Natural killer (NK) cell activity in patients with various malignancy against a variety of target cell lines: re-evaluation of clinical significance of natural killer cell activity.

Sixty-eight patients with various malignancy was examined for their natural killer (NK) cell activity against 14 target cell lines. The group consisted of 10 patients with gastric cancer, 10 patients with lung cancer, 8 patients with hepatoma, 11 patients with cancer of female genital organs, 14 patients with malignant lymphoma and 15 patients with acute myelogenous leukemia (AML). The target cells from a variety of lineage were selected to examine the disease-related specificity in NK cell activity. The peripheral mononuclear cells from patients with gastric cancer did not show a decrease in NK activity against 14 targets including gastric cancer cell lines. Other patients except for AML demonstrated low NK activity against one or two target cells out of 14 targets. Whereas, NK activity in patients with AML was remarkably depressed against 10 target cells out of 14. At single cell assay, killing ability rather than binding activity to target was markedly impaired in AML. Comprehensively, the data demonstrated the marked difference in the NK level between the patients with solid tumor and the patients with hematopoietic malignancy. There existed neither disease-related specificity in NK cytolysis, nor correlation in NK levels and clinical severity in the patients with malignancy. These results suggested that it was very difficult to evaluate the anti-cancer capacity in patients with malignancy by NK activity alone.

Adolescent↗