Frequency Of Other Types Research Articles

CYTOGENETIC INVESTIGATION OF THALLIUM-POISONED PEOPLE: PILOT STUDY

Thirteen blood samples of thallium-poisoned people were cytogenetically investigated. The thallium concentration in blood varied from 25 to 2700 mug/L. The mean frequency of chromosomal aberrations in the poisoned group significantly exceeded our control level (7.08 +/--2.19% and 2.03 +/--0.25, p < .001). The rate of single fragments was significantly higher in poisoned group (7.77 +/- 2.68% and 1.59 +/- 0.23% , p < .001) while the frequencies of other types of chromosomal aberrations were similar in both groups. It is possible that thallium is an S-dependent clastogenic agent because the majority of the structural aberrations are of the chromatid type. Irrespective of mechanisms, damage to genetic material was revealed in thallium-poisoned people.

Preliminary tests of a cognitive model of generalized anxiety disorder

Although worry is the central feature of Generalised Anxiety Disorder (GAD), little is known about the factors that contribute to pathological or problematic worry. In a recent cognitive model of GAD, Wells, A. (1995) proposed that negative appraisal of worrying itself (meta-worry or type 2 worry) should be distinguished from other types of worrying (type 1 worry). A central feature of this model is the idea that individuals with GAD hold rigid positive beliefs about the usefulness of worrying as a coping strategy. However, these individuals also hold negative beliefs and appraise worrying as uncontrollable and dangerous. This combination of cognitions and associated responses leads to an increased frequency and generality of worrying, and thus to the pathological worry characteristic of GAD. This paper reports a preliminary test of the hypothesis that meta-worry contributes to problematic and pathological worrying, and this relationship is independent of the frequency of other types of worry. In testing for associations between worry dimensions we controlled for overlaps with Trait anxiety, and the controllability of worrying. Results of a series of regression analyses support the hypothesis that pathological worry is associated with meta-worry and this association is independent of Trait-anxiety and type 1 worry. The clinical implications of these data are briefly discussed.

The Role of Fire During Climate Change in an Eastern Deciduous Forest at Devil's Bathtub, New York

Annual records of charcoal and sedimentation rate were compared with fossil pollen to investigate the role of fire in eastern deciduous forest around Devil's Bathtub, New York, USA. Changes in peak and background charcoal suggest that changes in fire regime have accompanied the principal vegetation and climatic changes of the last 10 400 yr. A distribution of return times (50—200—yr intervals) similar to parts of modern boreal Canada prevailed when late—Glacial spruce woodland dominated the site. Expansion of Pinus banksiana appears to have altered the fire regime to one of crown fires with high particulate emissions, but return intervals similar to those of the preceding Picea forest. Expansion of Pinus strobus might be linked to change in fire occurrence, but the broad dispersal of Pinus pollen makes interpretation difficult. If Pinus strobus expansion around the site is reflected in its pollen curve, then that expansion coincides with a time of frequent fire. Alternatively, if increasing pollen abundance precedes the local expansion of trees, as has been observed elsewhere, then local expansion might correspond to an abrupt decline in fire frequency and in regional importance of fire. An abrupt decline in background charcoal follows a fire and coincides $(\pm 100 yr)$ with the expansion of hardwood taxa such as Fagus. The decline in background charcoal occurs over several years, suggesting that it may be linked to effects of hardwood expansion on fuels. Fires do not appear to have occurred during the time of hardwood dominance, suggesting that fire may not be an explanation for maintenance of species diversity in this deciduous forest. However, frequent occurrence of thick varves during the latter half of the Holocene suggests that the frequency of other types of disturbance may have increased.

Ploidy of somatic embryos and the ability to regenerate plantlets in melon (Cucumis melo L.)

The number of chromosomes in cells of callus, somatic embryos and regenerated plantlets during somatic embryogenesis were examined in two cultivars of melon (Cucumis melo L.). Somatic embryos were diploid (50.0%/32.1%), tetraploid (38.5%/57.5%) and octoploid (11.5%/10.4%) whereas in callus cells diploidy (41.9%/43.3%), tetraploidy (27.9%/25.8%), octoploidy (11.6%/15.5%) and a low frequency of other types of ploidy and aneuploidy were observed. Mixoploid somatic embryos were not observed. These results suggest that the somatic embryos were selectively differentiated from diploid, tetraploid and octoploid cells, and that endopolyploidization of cultured cells occurred before the start of cell division leading to somatic embryogenesis. The ratio of diploid to tetraploid (1.30/0.55) in somatic embryos was less than that in callus cells (1.50/1.68) while ratios of diploid to octoploid (4.35/3.09) and tetraploid to octoploid (3.35/5.52) in somatic embryos were greater than those in callus cells (3.61/2.80 and 2.40/1.67). Therefore, it appears that the ability of callus cell to differentiate into somatic embryos increases in the following order: octoploid < diploid < tetraploid. Regenerated plantlets were diploid (65.5%/55.1%) and tetraploid (34.5%/44.9%). No octoploid plantlets were observed. The ratio of diploid to tetraploid in regenerated plantlets (1.72/1.23) was greater than that in somatic embryos. Therefore, it appears that the ability of somatic embryos to develop into plantlets increases in the following order: octoploid < tetraploid < diploid.

P53 mutations in human lymphoid malignancies: association with Burkitt lymphoma and chronic lymphocytic leukemia.

We have investigated the frequency of p53 mutations in B- and T-cell human lymphoid malignancies, including acute lymphoblastic leukemia, the major subtypes of non-Hodgkin lymphoma, and chronic lymphocytic leukemia. p53 exons 5-9 were studied by using genomic DNA from 197 primary tumors and 27 cell lines by single-strand conformation polymorphism analysis and by direct sequencing of PCR-amplified fragments. Mutations were found associated with (i) Burkitt lymphoma (9/27 biopsies; 17/27 cell lines) and its leukemic counterpart L3-type B-cell acute lymphoblastic leukemia (5/9), both of which also carry activated c-myc oncogenes, and (ii) B-cell chronic lymphocytic leukemia (6/40) and, in particular, its stage of progression known as Richter's transformation (3/7). Mutations were not found at any significant frequency in other types of non-Hodgkin lymphoma or acute lymphoblastic leukemia. In many cases, only the mutated allele was detectable, implying loss of the normal allele. These results suggest that (i) significant differences in the frequency of p53 mutations are present among subtypes of neoplasms derived from the same tissue; (ii) p53 may play a role in tumor progression in B-cell chronic lymphocytic leukemia; (iii) the presence of both p53 loss/inactivation and c-myc oncogene activation may be important in the pathogenesis of Burkitt lymphoma and its leukemic form L3-type B-cell acute lymphoblastic leukemia.

Induction of specific base-pair substitutions in E. coli trpA mutants by chloroenthylene oxide, a carcinogenic vinyl chloride metabolite

Chloroethylene oxide (CEO), an ultimate carcinogenic metabolite of vinyl choride, induces base-pair substitution mutations but not frameshift mutations in bacteria. The mutational specificity of CEO was investigated in Escherichia coli, using the trpA mutants developed by Yanofsky. Reversion frequencies to tryptophan prototrophy were analysed, and CEO was found to induce more GC → AT transitions than AT → TA transversions, in addition to a low frequency of other types of substitution. This specificity indicates that CEO is mutagenic through a miscoding DNA adduct. The results are discussed in relation to the various CEO-DNA adducts formed and to their reported or expected mispairing properties

Epidemiology of parkinsonism: Incidence, classification, and mortality

An epidemiological study of parkinsonism over a 13-year period (1967 through 1979) is presented, updating previous reports on incidence and trend in the population of Rochester, Minnesota. The overall average annual incidence of parkinsonism per 100,000 population was 20.5, adjusted to the 1970 total United States population, which is virtually unchanged from previous observations. Incidences calculated for each calendar year (1967 through 1979) revealed no remarkable change following the 1976 swine flu vaccination program. There was no sex difference and the peak incidence occurred between ages 75 and 84 years. Idiopathic Parkinson's disease was the most common variant (86%), followed by drug-induced parkinsonism (7%). There were no new cases of postencephalitic parkinsonism diagnosed during the study period. Relative frequency of other types of Parkinson's disease as identified by practicing neurologists is presented. For each case two age- and sex-matched controls were selected from the Rochester population. The survival rates in the controls were comparable to the general population of the west north central region of the United States. The mortalities in the patients were significantly higher (p = 0.001) than the controls and were unchanged from previous rates reported from the same community. In the 69 (50%) patients treated with levodopa, the mortality was comparable to that in controls. The favorable outcome in these cases is attributed to bias resulting from selection of healthier patients for treatment.

Comparative Carcinogenicity of &lt;italic&gt;N&lt;/italic&gt;-Butyl-&lt;italic&gt;N&lt;/italic&gt;-(3-carboxypropyl)-nitrosamine and &lt;italic&gt;N&lt;/italic&gt;-Butyl-&lt;italic&gt;N&lt;/italic&gt;-(4-hydroxybutyl)nitrosamine for the Urinary Bladder of (C57BL/6 × DBA/2)F&lt;sub&gt;1&lt;/sub&gt; Mice&lt;xref ref-type="fn" rid="FN2"&gt;2&lt;/xref&gt;

The carcinogenicity of N-butyl-N-(3-carboxypropyl)-nitrosamine [CAS: 38252-74-3; 4-(N-butyl-N-nitrosamino)butyric acid] in male and female (C57BL/6 X DBA/2)F1 mice was determined. N-Butyl-N-(3-carboxypropyl)nitrosamine given in the drinking water at a concentration of 3 mM (0.056%) for 13 weeks induced only carcinoma of the urinary bladder in both sexes. At 22-28 weeks, the incidences of bladder cancer in the male and female mice were 100 and 88%, respectively. These bladder tumors were classified histologically according to the frequency (%) of tumor type: pure transitional cell carcinoma, 42%; mixed (transitional cell carcinoma with squamous or glandular differentiation, or both), 28%; squamous cell carcinoma, 27%; and carcinoma in situ, 3%. No significant sex differences were observed. In comparative studies, the incidence of bladder cancer was 100% for both sexes after administration of 3 mM (0.052%) N-butyl-N-(4-hydroxybutyl)nitrosamine [CAS: 3817-11-6; 4-(butylnitrosoamino)-1-butanol] in the drinking water. The frequency of pure transitional cell carcinoma was 47%, which was not significantly different from that observed for the carboxypropyl compound. The frequencies of other types of bladder carcinoma induced by N-butyl-N-(4-hydroxybutyl)nitrosamine were the following: mixed, 8%; squamous cell carcinoma, 42%; and carcinoma in situ, 3%.

ADDISON'S DISEASE – CLINICAL STUDIES. A REPORT OF 108 CASES

ABSTRACT One hundred and eight cases of Addison's disease, diagnosed in Danish medical departments between 1950 and 1972, were reviewed. The idiopathic type of Addison's disease predominated (66 %) while tuberculous Addisons's disease comprised only 17 % of the present series. The remaining 17 % were unclassifiable on clinical grounds. One third of the cases had symptoms less than three months prior to diagnosis and 25 % of the patients were in need of immediate treatment because of manifest or impending crisis when admitted to the hospital. Idiopathic Addison's disease was diagnosed in all age groups, predominantly in females, while patients with tuberculous Addison's disease were preferably males of higher ages. A second disease (diabetes mellitus, thyroid disorders, pernicious anaemia or gonadal insufficiency) was diagnosed in 53 % of the patients with idiopathic Addison's disease. Associated diseases were found with significantly reduced frequency in other types of Addison's disease.

Crises tônicas axiais e crises acinéticas: estudo clínico longitudinal de pacientes tratados com derivados benzodiazepinicos

Com o uso de Nitrazepam notou-se rápida redução de freqüência das crises tônicas axiais. Os melhores resultados foram obtidos em um paciente que apresentava crises tônicas axiais isoladas, estado seqüela de encefalopatia mioclônica infantil com hipsarritmia; essas crises foram controladas após dois meses de tratamento. Em outro paciente, com manifestações críticas próprias das síndrome de Lennox, houve redução da intensidade e da freqüência das demais crises associadas às crises tônicas axiais; o tratamento não impediu, contudo, o aparecimento de novas manifestações epilépticas que completaram o quadro da síndrome de Lennox. A intercorrência de episódios infecciosos piorou o quadro clínico de um dos pacientes. Houve redução rápida e significativa da intensidade e da freqüência das crises acinéticas, desde o primeiro dia de tratamento com Diazepam em 5 dos 10 pacientes. Em mais 4 doentes as crises foram controladas desde o primeiro dia. O intervalo entre o início das crises acinéticas e o início do tratamento e o insucesso de terapêuticas anteriores não foram fatores desfavoráveis quanto aos resultados obtidos com o Diazepam. Recidivas ou agravamento do quadro clínico ocorreram em 5 pacientes. A piora não teve relação definida com afecções intercorrentes. Aumentos ulteriores da dosagem do Diazepam tiveram efeitos inconstantes.

SIDE EFFECTS OF ORAL CONTRACEPTIVES AN INVESTIGATION OF 4 GESTAGENS USING A DOUBLE BLIND CROSSOVER TECHNIQUE

Preliminary data are reported from a double blind crossover study of the side effects of 4 different oral contraceptives (megestrol acetate 4 mg plus ethynylestradiol .05 mg 3-Deoxynorethindrone 2.5 mg plus methyl-ethynylestradiol .075 mg Norethindrone acetate 3 mg plus ethynylestradiol .05 mg and Ethynodiol diacetate 1 mg plus methyl-ethynylestradiol .1 mg). Each subject received the 4 preparations randomly distributed during 4 cycles and thereafter in the same order of distribution during 8 more cycles. The study thus comprised altogether 12 cycles for each subject. Ninety subjects were included in this preliminary report and the total number of cycles was 913. No serious side effects were found. No pregnancy occurred during the study. Volidan showed a significantly higher frequency of intermenstrual spotting and bleeding than the other combinations. The average weight change induced by the 4 preparations also differed and Volidan did not seem to produce the same tendency to weight increase as the other preparations. A higher frequency of nausea and vomiting was observed during Ovulen therapy than during therapy with the other preparations but statistical analysis has not yet been performed. No significant difference in the frequency of other types of side effects could be found between the 4 preparations.((Full text))