Study of an injection-seeded supra-atmospheric CO(2) laser operated below emission threshold with a ring cavity

The dynamics and tuning range of an injection-seeded supra-atmospheric CO(2) laser operated at a pressure of 10 atm with a ring cavity are studied theoretically and experimentally. When the losses of such a laser are sufficiently high, the short lifetime of the gain does not permit the buildup of intense pulses that start from spontaneous emission noise; the laser is then said to be operated below emission threshold. Under such circumstances, injection seeding with a few milliwatts of a single-mode signal permits nearly full extraction of the available power. The extraction efficiency is shown to depend in a sensitive manner on the frequencies of a cavity mode and of the injected signal. When these two frequencies are mismatched, a lower power is extracted, and two-mode emission takes place. The laser is shown to be tunable over 41 transition lines of the CO(2) spectrum.

Regional localization of human chromosome 15 loci

One hundred forty-nine chromosome 15 loci were mapped by PCR with respect to chromosome breakpoints in three somatic cell hybrids retaining total or part of chromosome 15 and to a 10-Mb YAC contig. This chromosome was subdivided into 5 regions, yielding an average resolution of more than 1 sequence tagged site per megabase. The mapped loci included 18 genes, 60 cDNA-derived sequence tagged sites, and 69 microsatellites. In addition, the amount of chromosome 15 retained in line A15.1 has been defined. This work represents the first attempt at an integration of the human physical, expression, and genetic maps of chromosome 15.

Mapping of a chromosome 15 region involved in limb girdle muscular dystrophy

A gene responsible for an autosomal recessive form of limb girdle muscular dystrophy (LGMD2, MIM number 253600) has been localized on chromosome 15. After genotyping additional markers of this chromosome, two were found to flank the disease locus within an interval that was assessed as 7 centiMorgans. The screening of the CEPH YAC libraries with the corresponding probes allowed the isolation of YACs which were used in fluorescence in situ hybridization to define the LGMD2 cytogenetic interval as 15q15.1-15q21.1. Four different approaches were pursued for the establishment of the physical map of this area which allowed the assembly of an uninterrupted YAC contig spanning an estimated 10-12 megabases, with an average STS resolution of 140 kb or for the 25 polymorphic microsatellites on this map, of 400 kb. Twelve genes and 25 genetic markers were positioned in this contig, which is constituted of a minimum of 10 clones.

Phase II trial of intraperitoneal carboplatin in ovarian carcinoma patients with macroscopic residual disease at second-look laparotomy. A multicentre study of the French Fédération Nationale des Centres de Lutte Contre le Cancer

BACKGROUND

Because of its antitumour activity and its pharmacological advantage when administered by the intraperitoneal route, carboplatin was studied in a phase II multicentric trial. The aim of the study was to determine the response rate and the toxicity of carboplatin administered intraperitoneally and to determine if pathological complete response could be attained in women with macroscopic residual ovarian cancer at second-look laparotomy after intravenous cisplatin chemotherapy.

PATIENTS AND METHODS

Twenty-nine patients with macroscopical residual disease after intravenous cisplatin-based chemotherapy at second-look laparotomy, were treated at that time with 300 mg/m2 of carboplatin administered in the abdominal cavity every four weeks for six cycles. In instances of negative findings at physical and CT scan examination, laparotomy evaluation was performed and the catheter was removed. The dose of carboplatin was increased or decreased according to hematological toxicity.

RESULTS

Efficacy is evaluable in 25 pts: 2 pts had pathological complete responses and 1 pt had microscopic disease (12% response rate of evaluable patients). Toxicity is evaluable for 135 cycles in 29 patients. No grade 4 hematological toxicity was observed, 2 pts had grade 3 leukopenia and 3 pts had grade 3 thrombocytopenia; grade 3 vomiting was observed in 11% of cycles. No peritoneal complication was observed; catheter dysfunction occurred after the first cycle in one patient who refused a surgical procedure to remove the catheter and to pursue treatment.

CONCLUSION

Intraperitoneal carboplatin demonstrates efficacy in patients with macroscopical residual disease at second-look laparotomy after first-line cisplatin chemotherapy. The recommended dose for further studies is 300 mg/m2 administered every 4 weeks. A low response rate does not favour a randomised study.

Targeted development of microsatellite markers from inter-Alu amplification of YAC clones

Primary genetic maps based on highly informative markers are now available. The local density of these markers may, however, not be sufficient. There is thus a need for new means to generate polymorphic markers from targeted regions of the genome. This can be achieved by selectively cloning and sequencing (CA)n-positive human inter-Alu sequences from targeted YAC clones. This method was tested on 21 YACs and led to the development of seven new polymorphic microsatellite markers.

A linkage map of human chromosome 15 with an average resolution of 2 cM and containing 55 polymorphic microsatellites

We have constructed a 2.0 centiMorgan (cM) resolution genetic linkage map for chromosome 15q that contains 55 polymorphic satellites and 3 RFLPs that have placed on the map with odds for order of at least 1,000:1. Genotypes from 67 polymorphic loci (64 polymorphic microsatellites) were used to construct the map. Nine genes are included in the 1,000:1 map and 37 markers have heterozygosities of at least 70%. The sex-equal map length is 128 cM and the largest genetic interval is 11 cM (15.5 cM on the female map). The female and male map lengths are 150 cM and 106 cM, respectively. The map was constructed with 'MultiMap' and is based on the CEPH reference pedigrees and includes over 12,000 new genotypes. A sub-set of 12 markers spanning the length of the linkage map were genotyped in a somatic cell hybrid panel with breakpoints that divided 15q into five segments. Cytogenetic placement agreed with the linkage positions for each of the microsatellites tested with the exception of one (ACTC) which failed to give consistent results. Ten spontaneous new mutations were identified from a subset of 42 polymorphic microsatellites (out of a total of 20,420 transmissions), giving an apparent observed spontaneous mutation rate of 5 x 10(-4) per locus. An integrated map of chromosome 15q was also constructed with the microsatellite markers described here and previously genotyped RFLP-based markers. The sex average map spans 144.7 cM with an average distance between unique map locations of 3.5 cM and a maximum intermarker distance of 11.5 cM. These genetic linkage maps can be considered baseline maps for 15q which will be useful for physical mapping and the localization of disease genes and other genes of interest.

The gene for creatine kinase, mitochondrial 2 (sarcomeric; CKMT2), maps to chromosome 5q13.3

YAC clones for the creatine kinase, mitochondrial 2 (sarcomeric; CKMT2), gene were isolated. One of these YACs was localized on chromosome 5q13.3 by fluorescence in situ hybridization. A polymorphic dinucleotide repeat (heterozygosity 0.77) was identified within the seventh intron of the CKMT2 gene. Genotyping of CEPH families allowed positioning of CKMT2 on the multipoint map of chromosome 5 between D5S424 and D5S428, distal to spinal muscular atrophy (SMA) (5q12-q14).

Mapping of the formin gene and exclusion as a candidate gene for the autosomal recessive form of limb-girdle muscular dystrophy

Limb-Girdle Muscular Dystrophy (LGMD) is a myopathy with clinical and transmission heterogeneity. The recessive form, LGMD2, has been recently mapped by linkage analysis to 15q. As an attempt to identify the gene involved in this pathology, we tested as candidate gene the LD locus, called LD for limb deformity. This gene has recently been identified and mapped to chromosome 15q13-q14. It is homologous to the murine formin gene which is localized to mouse chromosome 2. Mutations in this murine gene have been shown to cause limb deformity and kidney defect. YAC clones containing the LD gene were isolated and utilised to confirm the cytogenetic localisation. Internal DNA polymorphisms of the LD locus were analyzed in LGMD2 and CEPH families. The LD gene was mapped between the alpha cardiac actin gene and the D15S24 locus. Crossovers between the LGMD2 and the LD loci excluded the LD gene as a candidate for LGMD2.

Evidence of genetic heterogeneity in the autosomal recessive adult forms of limb-girdle muscular dystrophy following linkage analysis with 15q probes in Brazilian families

The autosomal recessive limb-girdle muscular dystrophies (LGMD) represent a heterogeneous group of diseases which may be characterised by one or more autosomal loci. A gene at 15q has recently been found to be responsible for a mild form of LGMD in a group of families from the isolated island of Réunion, now classified as LGMD2. Based on results of eight out of 11 large Brazilian LGMD families of different racial background (which were informative for the closest available probe to the LGMD2 gene), we confirmed linkage to the LGMD2 gene at 15q in two of these families and exclusion in six others. These data provide the first evidence of genetic heterogeneity for the autosomal recessive limb-girdle muscular dystrophies.

Effect of lime composition on the formation of reactive oxygen species from areca nut extract in vitro

Lime, representative of that used by betel quid chewers, was collected in a region of Papua New Guinea where the incidence of oral cancer is high. The free calcium hydroxide content and pH of 25 lime samples were highly correlated with the generation of reactive oxygen species from areca nut extract in vitro, and DNA damage in vitro, measured as 8-hydroxy-2'-deoxyguanosine. Fe2+ and Mg2+ levels in the lime samples were too low to modify formation of reactive oxygen species, but hydrogen peroxide formation was almost entirely inhibited by addition of Mg2+ to the reaction mixture. These results suggest that the calcium hydroxide content of lime in the presence of areca nut is primarily responsible for the formation of reactive oxygen species which might cause oxidative damage in the DNA of buccal mucosa cells of betel quid chewers.

High-grade malignant cutaneous plasmacytoma metastatic to the central nervous system. A case report with electron microscopy, immunohistological, and neuropathological studies

A case of high-grade malignant extramedullary plasmacytoma (EMP), unusual in its initial cutaneous localization and major involvement in the central nervous system rapidly resulting in death, is reported. Light- and electron-microscopic studies of a skin nodule revealed a high proportion of immature and mature plasmacytes. Immunohistological study revealed that both cells synthesized different amounts of a monotypic cytoplasmic kappa light chain. Neuropathological study revealed extensive infiltration of the leptomeninges and perivascular spaces as far as the deep parenchyma. In several places, effraction of vessels resulted in parenchymatous, tumor-like, plasmacytic infiltration. The findings of this case were compared with those of the few previously reported cases of EMP with initial cutaneous or intracranial localization, and with those of immunoblastic sarcoma occurring in some cases of myeloma.