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Biomedical subjects

M J Levin

Publications and source records attributed to M J Levin.

204 records · Page 12Linked to original sources
PubMedDate not supplied

Use of trimethoprim-sulfamethoxazole to prevent bacterial infections in children with acute lymphoblastic leukemia.

We assessed the efficacy of prophylactic antibiotics in children receiving intensive chemotherapy for acute lymphoblastic leukemia. The patients were randomized to receive either trimethoprim-sulfamethoxazole (TMP-SMX) or placebo in a double-blind trial. Thirty patients were evaluated in each group. Children receiving TMP-SMX had fewer episodes of bacteremia (0 vs. 5) and otitis media (3 vs. 18). The geometric mean of the neutrophil nadir was 172 in the TMP-SMX group and 287 in controls. However, no increased delay or dose reduction of chemotherapy was observed in the TMP-SMX treated patients. Five patients who received TMP-SMX developed Gram-negative rods resistant to TMP-SMX on surveillance stool cultures. We conclude that TMP-SMX prophylaxis decreased certain bacterial infections in children with acute lymphoblastic leukemia without causing clinically significant toxicity. The emergence of Gram-negative rods resistant to TMP-SMX in treated patients suggests that TMP-SMX prophylaxis should be restricted to patients who are at high risk for developing a bacterial infection or Pneumocystis carinii pneumonia.

Administration, Oral↗
PubMedDate not supplied

In vitro evaluations of condoms with and without nonoxynol 9 as physical and chemical barriers against Chlamydia trachomatis, herpes simplex virus type 2, and human immunodeficiency virus.

Simulated in vitro intercourse conditions demonstrated that unlubricated latex condoms provide an effective physical barrier to high concentrations of Chlamydia trachomatis, herpes simplex virus type 2, and human immunodeficiency virus. However, since condoms can be damaged after manufacturing inspection and prior to use, latex condoms alone should not be perceived as absolute protection against STDs. Nonoxynol 9 used in conjunction with condoms provided additional, yet still not foolproof, protection against the three viruses.

Chlamydia trachomatis↗
PubMedDate not supplied

The Trypanosoma cruzi genome project: nuclear karyotype and gene mapping of clone CL Brener.

By using improved pulsed field gel electrophoresis conditions, the molecular karyotype of the reference clone CL Brener selected for Trypanosoma cruzi genome project was established. A total of 20 uniform chromosomal bands ranging in size from 0.45 to 3.5 Megabase pairs (Mbp) were resolved in a single run. The weighted sum of the chromosomal bands was approximately 87 Mbp. Chromoblots were hybridized with 39 different homologous probes, 13 of which identified single chromosomes. Several markers showed linkage and four different linkage groups were identified, each comprising two markers. Densitometric analysis suggests that most of the chromosomal bands contain two or more chromosomes representing either homologous chromosomes and/or heterologous chromosomes with similar sizes.

Animals↗
PubMedDate not supplied

Towards the physical map of the Trypanosoma cruzi nuclear genome: construction of YAC and BAC libraries of the reference clone T. cruzi CL-Brener.

Strategies to construct the physical map of the Trypanosoma cruzi nuclear genome have to capitalize on three main advantages of the parasite genome, namely (a) its small size, (b) the fact that all chromosomes can be defined, and many of them can be isolated by pulse field gel electrophoresis, and (c) the fact that simple Southern blots of electrophoretic karyotypes can be used to map sequence tagged sites and expressed sequence tags to chromosomal bands. A major drawback to cope with is the complexity of T. cruzi genetics, that hinders the construction of a comprehensive genetic map. As a first step towards physical mapping, we report the construction and partial characterization of a T. cruzi CL-Brener genomic library in yeast artificial chromosomes (YACs) that consists of 2,770 individual YACs with a mean insert size of 365 kb encompassing around 10 genomic equivalents. Two libraries in bacterial artificial chromosomes (BACs) have been constructed, BACI and BACII. Both libraries represent about three genome equivalents. A third BAC library (BAC III) is being constructed. YACs and BACs are invaluable tools for physical mapping. More generally, they have to be considered as a common resource for research in Chagas disease.

Animals↗
PubMedDate not supplied

Parasite genome projects and the Trypanosoma cruzi genome initiative.

Since the start of the human genome project, a great number of genome projects on other "model" organism have been initiated, some of them already completed. Several initiatives have also been started on parasite genomes, mainly through support from WHO/TDR, involving North-South and South-South collaborations, and great hopes are vested in that these initiatives will lead to new tools for disease control and prevention, as well as to the establishment of genomic research technology in developing countries. The Trypanosoma cruzi genome project, using the clone CL-Brener as starting point, has made considerable progress through the concerted action of more than 20 laboratories, most of them in the South. A brief overview of the current state of the project is given.

Animals↗