Attachment,spreading and growthin vitro of highly malignant and low malignant murine fibrosarcoma cells

Highly malignant cell lines and low-malignant cell lines isolated from three different methylcholanthrene-induced murine fibrosarcomas were examined for their ability to attach to plastic dishes and collagen-coated dishes under serumfree conditions and in the presence of serum. Most of the cells from the three highly malignant lines attached and spread under all conditions. By 72h, there was a significant increase in the number of cells indicating that at least some of the cells had undergone division (even in the absence of serum). In contrast, fewer of the cells from the three low-malignant lines attached and spread on the plastic or collagen substrates in the absence of serum or in the presence of 0.1 per cent serum. However, when 15g laminin per dish was added along with the lowmalignant cells, they then attached and spread on the plastic and collagen-coated dishes. Previous studies have indicated that the highly malignant lines express cell surface antigens that cross-react with laminin while the low-malignant cell lines do not. We speculate that the differences between the high- and low-malignant cells in the expression of cell surface laminin-like antigens contribute to the dissimilarities in attachment and spreading capacity. These differences may also contribute to the dissimilarity between these cells in malignant potential.     

Direct detection of Mycobacterium tuberculosis complex in clinical samples from patients in Norway by ligase chain reaction.

Our aim was to investigate the use of DNA amplification with the ligase chain reaction (LCR) for detection of the Mycobacterium tuberculosis complex directly in human clinical specimens. The LCR assay employed was the Abbott LCx MTB Assay, which uses the gene encoding protein antigen b as the target template. Four hundred eighty-two samples from 457 patients in one clinical microbiology laboratory in Norway were processed by routine culture analysis (BACTEC culture), direct microscopy (Ziehl-Neelsen staining) and LCR. Of the 118 specimens containing cultivable M. tuberculosis, 106 (90.6%) were detected by LCR. Among the 364 culture-negative specimens, 356 samples were negative also by LCR and 8 (1.6%) were positive by LCR. In five of the eight LCR-positive and culture-negative samples, another sample from the same patient was M. tuberculosis culture positive and/or the patient had symptoms of tuberculosis. In comparison with culture, the sensitivity of LCR was 96.7% for smear-positive samples and 72.0% for smear-negative samples, respectively. For all samples combined, the sensitivity, specificity, and positive and negative predictive values were 90.2, 99.2, 97.4, and 96.7%, respectively. Challenging the M. tuberculosis LCR test with DNAs and cultures from strains of Mycobacterium ulcerans and Mycobacterium marinum, which are the mycobacterial species most closely related to the M. tuberculosis complex, resulted in all-negative test results. The sensitivity, specificity, and positive and negative predictive values of BACTEC culture in comparison with the LCR test and clinical criteria were 95.9, 100, 100, and 98.6%, respectively. A certain prioritization of samples subjected to the LCR assay should be based on clinical indications and risks with regard to infection transmission and patient isolation policy. More automation and lower expenses are generally desired for nucleic acid amplification kits. However, this M. tuberculosis LCR assay represents a valuable tool in routine mycobacterial diagnostics.     

Autosomal genetics and Y-chromosome haplogroup L1b-M317 reveal Mount Lebanon Maronites as a persistently non-emigrating population

Currently, there are 18 different religious communities living in Lebanon. While evolving primarily within Lebanon, these communities show a level of local isolation as demonstrated previously from their Y-haplogroup distributions. In order to trace the origins and migratory patterns that may have led to the genetic isolation and autosomal clustering in some of these communities we analyzed Y-chromosome STR and SNP sample data from 6327 individuals, in addition to whole genome autosomal sample data from 609 individuals, from Mount Lebanon and other surrounding communities. We observed Y chromosome L1b Levantine STR branching that occurred around 5000 years ago. Autosomal DNA analyses suggest that the North Lebanese Mountain Maronite community possesses an ancestral Fertile Crescent genetic component distinct from other populations in the region. We suggest that the Levantine L1b group split from the Caucasus ancestral group around 7300 years ago and migrated to the Levant. This event was distinct from the earlier expansions from the Caucasus region that contributed to the wider Levantine populations. Differential cultural adaption by populations from the North Lebanese Mountains are clearly aligned with the L1b haplotype STR haplogroup clusters, indicating pre-existing and persistent cultural barriers marked by the transmission of L1b lineages. Our findings highlight the value of uniparental haplogroups and STR haplotype data for elucidating biosocial events among these populations.Subject terms: Population genetics, Computational biology and bioinformatics     

Cardiac auscultation training of medical students: a comparison of electronic sensor-based and acoustic stethoscopes

Background  

To determine whether the use of an electronic, sensor based stethoscope affects the cardiac auscultation skills of undergraduate medical students.     

Somatic spectrum of cancer-associated single basepair substitutions in the TP53 gene is determined mainly by endogenous mechanisms of mutation and by selection

The spectrum of somatic TP53 single basepair substitutions detected in 955 cancers was compared with that of 2,224 different germline mutations in 279 different human genes (other than TP53), reported as the cause of inherited disease. This comparison reveals that, disregarding a relatively small subset (12%) of TP53 mutations that probably result from the action of exogenous mutagens, both the relative rates and the nearest-neighbor spectra of single basepair substitutions are similar in the two datasets. This spectral resemblance suggests that a substantial proportion of cancer-associated somatic TP53 mutations result from endogenous cellular mechanisms. The likelihood of clinical observation of a particular mutation type differs, however, between tumors and genetic diseases, when the chemical properties of the resulting amino acid substitutions are considered. Together with a sixfold higher observation likelihood for mutations at evolutionary conserved residues, this finding argues that selection is a critical factor in determining which TP53 mutations are found to be associated with human cancer. © 1995 Wiley-Liss, Inc.     

Rheumatoid arthritis may be primarily associated with HLA-DR4 molecules sharing a particular sequence at residues 67–74

Genomic typing of in vitro amplified DNA with sequence-specific oligonucleotide (SSO) probes was performed for DRB1, DQA1, DQB1, DPA1 and DPB1 alleles in 54 random Norwegian rheumatoid arthritis (RA) patients and 181 healthy controls. DRB1 alleles encoding the serological specificity DR4 were found in 80% of the patients, compared to 34% of the controls (relative risk = 7.9, p less than 0.0001). All DR4-positive RA patients carried either DRB1*0401 (Dw4), 0404 (Dw14), or 0405 (Dw15), while no patients were found to carry DRB1*0402 (Dw10) or 0403 (Dw13). The frequency of the DRB1*0101 allele encoding DR1 was not increased, even among DR4-negative RA patients, and we were unable to detect any sharing of other class II alleles among DR4-negative patients. No contribution of any DQA1, DQB1, DPA1 or DPB1 alleles to RA susceptibility could be detected. The results suggest that in the Norwegian population RA is primarily associated with a shared sequence at residues 67-74 of the DR beta 1 chain, but only when this sequence is expressed on DR4 molecules.     

Sera from preeclamptic women increase the content of triglycerides and reduce the release of prostacyclin in cultured endothelial cells

The causes of the "endothelial dysfunction" accompanying preeclampsia are unknown. Women with preeclampsia have a marked hyperlipidemia which reflects altered lipid metabolism. We asked if the hyperlipidemic sera of preeclamptic women could cause altered endothelial cell properties. Cultured endothelial cells were incubated with sera from women with preeclampsia (PE) or normal pregnancies as controls. Fifty PE-sera were tested and in 45 cases the endothelial cells acquired a large number of sudanophilic granules which by electron microscopy had lipid appearance. In 31 incubations with 31 individual control sera cellular lipid granules were observed in 4 cases. The cellular triglyceride content was increased to 153 +/- 30 compared to 48 +/- 10 micrograms/mg cell protein in the control cells. Furthermore, the endothelial release of prostacyclin, measured as 6-keto PGF1 alpha, was 8.8 +/- 0.6 ng/mg cell protein in cells incubated with PE-sera as compared to 40.3 +/- 6.4 ng/mg in the control cells. Conclusion: The hyperlipidemic sera from preeclamptic women induced triglyceride accumulation in cultured endothelial cells. This was accompanied by altered endothelial function as demonstrated by reduced prostacyclin release.     

Contact sensitivity reactions in the oral mucosa

In clinical practice, it is commonly assumed that occlusal splints have therapeutic value in the treatment of temporomandibular disorders (TMD), but the evidence based on randomized controlled trials is scarce. This study evaluated the short-term (10-week) efficacy of a stabilization splint in subjects with recurrent secondary otalgia and active TMD treatment need using a randomized, controlled, double-blind design. Thirty-six subjects were randomly allocated to the two treatment groups: the stabilization splint and the control splint group. After 10 weeks' treatment, the intensity of secondary otalgia, measured on a VAS scale (from 0 to 100 mm), decreased statistically significantly in the stabilization splint group (t 2.12; P 0.006), but not in the control group. Improvement in active TMD treatment need in subjects showing moderate or severe signs and symptoms of TMD was reported significantly more often in the stabilization splint group than in the control splint group (χ² 5.71; P .017). A statistically significant decrease in the Helkimo clinical dysfunction index was seen in the subjects with stabilization splint (Z -2.63; P .009), but not in the subjects with control splint. The results indicate that the use of a stabilization splint is beneficial with regard to secondary otalgia and active TMD treatment need.