Simplified intraoperative parathormone assay for primary hyperparathyroidism in a resource-limited setting

Background: The optimum threshold of IOPTH decay remains a debate and numerous criteria have been described. In this study, we utilize a single-sample IOPTH taken 10 min post excision. Materials & methods: This 4-year query of a prospectively maintained database included primary hyperparathyroidism patients with pre-operative PTH done 1 week prior to surgery, and a 10-min post excision IOPTH value. Optimal cut-off for PTH and sensitivity/specificity were calculated. Results: A total of 93 patients had single-gland disease, of whom 79 (84.9%) were symptomatic. The 10-min post excision assay sensitivity in single-gland disease was 97.8% (50% fall), 95% (60% fall) and 83.9% (70% fall). Conclusion: A post excision single-shot IOPTH assay with a 50% fall offers a sensitivity of 97.8% in patients of primary hyperparathyroidism with single-gland benign disease.

Evidence from Terminal Recombination Gradients that FtsK Uses Replichore Polarity To Control Chromosome Terminus Positioning at Division in Escherichia coli

ABSTRACT Chromosome dimers in Escherichia coli are resolved at the dif locus by two recombinases, XerC and XerD, and the septum-anchored FtsK protein. Chromosome dimer resolution (CDR) is subject to strong spatiotemporal control: it takes place at the time of cell division, and it requires the dif resolution site to be located at the junction between the two polarized chromosome arms or replichores. Failure of CDR results in trapping of DNA by the septum and RecABCD recombination (terminal recombination). We had proposed that dif sites of a dimer are first moved to the septum by mechanisms based on local polarity and that normally CDR then occurs as the septum closes. To determine whether FtsK plays a role in the mobilization process, as well as in the recombination reaction, we characterized terminal recombination in an ftsK mutant. The frequency of recombination at various points in the terminus region of the chromosome was measured and compared with the recombination frequency on a xerC mutant chromosome with respect to intensity, the region affected, and response to polarity distortion. The use of a prophage excision assay, which allows variation of the site of recombination and interference with local polarity, allowed us to find that cooperating FtsK-dependent and -independent processes localize dif at the septum and that DNA mobilization by FtsK is oriented by the polarity probably due to skewed sequence motifs of the mobilized material.

Distinct P-Element Excision Products in Somatic and Germline Cells of Drosophila melanogaster

The footprints remaining following somatic P-element excision from the Drosophila white locus were recovered and characterized. Two different types of footprints were observed. Over 75% of the footprints were short, composed of 4 or 7 nucleotides of the P-element inverted terminal repeat, and were similar to those found in a previously described plasmid excision assay. The remaining footprints were composed of 14–18 nucleotides of both inverted terminal repeats. These large footprints were indistinguishable from those recovered following germline P-element excision. Enhanced expression of the Drosophila homologue of the Ku70 protein did not affect the structure of the somatic footprints. Therefore, this protein is not a limiting factor for double-strand break repair by nonhomologous end-joining in Drosophila somatic cells.

Immunogenic Neoplastic Clones Derived in Vitro from an Originally Non-immunogenic BALB/c Fibrosarcoma

A non-immunogenic fibrosarcoma (SDC2), obtained by spontaneous neoplastic transformation of BALB/c fibroblasts cultured within a diffusion chamber kept in the peritoneal cavity of (BALB/c × C3Hf)F1 mice, was maintained in tissue culture for 10 passages. Three different clones were then derived from the in vitro neoplastic population. Each of the clones, the original in vivo tumor, and its in vitro line taken at the 10th passage (before cloning) were tested for the presence of individual tumor-associated transplantation antigens (TATA) by in vivo growth and excision assay. Contrary to the original SDC2 neoplasm, its in vitro line and 2 out of 3 clones (CL1-SDC2 and CL3-SDC2) were immunogenic, whereas the other clone (CL6-SDC2) displayed no immunogenicity. In addition, CL1-SDC2 and CL3-SDC2 were able to induce a reciprocal cross-protection in in vivo transplantation tests, thus showing common TATA; no cross-reactions were found between these clones and 2 other chemically-induced immunogenic sarcomas. The results suggest an antigenic heterogeneity in the original population of the nonimmunogenic SDC2 sarcoma, with the presence of antigenic but sub-immunogenic neoplastic cells.