Catheter associated bloodstream infection caused by R. radiobacter.

Rhizobium radiobacter is a gram negative bacillus that is infrequently recognized in clinical specimens but is emerging as an opportunistic human pathogen. Infections due to Rhizobium radiobacter are strongly related to the presence of foreign plastic material and effective treatment often requires removal of the device. We report a case of R. radiobacter bloodstream infection associated with a central venous catheter which was easily controlled by antimicrobial treatment and did not require removal of intravascular device. To the best of our knowledge, this is the first case report from India implicating R. radiobacter as a cause of human infection.

CCR5 chemokine receptor genotype frequencies among Puerto Rican HIV-1-seropositive individuals

Some individuals remain uninfected by human immunodeficiency virus type 1 (HIV-1), despite multiple sexual contacts with subjects with confirmed HIV-1 infection. Several studies have confirmed that individuals who are homozygous for a 32 base pair (bp) deletion mutation in the chemokine receptor gene CCR5, designated as delta 32/ delta 32, are protected against HIV-1 infection. Heterozygotes of the same chemokine receptor deletion mutation are, however, not protected from acquiring HIV-1 infection but seemingly have slower progression to acquired immunodeficiency syndromes (AIDS). Genotype frequencies of the delta 32 CCR5 mutation vary markedly among different ethnic groups; heterozygosity is found in approximately 15% of Caucasians, about 5-7% of Hispanics and African Americans and 1% or less of Asians. The ethnic background of Puerto Ricans is highly complex and usually includes admixture of Caucasian, Caribbean Indian and African traits to a varying extent. This study was conducted to examine the frequencies of the delta 32 CCR5 mutation among Puerto Ricans who are infected with HIV-1. Samples were received from different geographical regions of the island. Of 377 samples tested, 94.2% were wild type (non-deletion mutant) homozygotes, 5.8% were delta 32 CCR5 heterozygotes, and none were delta 32 CCR5 homozygotes. The incidence of CCR5 delta 32/w heterozygous mutation among Puerto Ricans seems to be somewhat lower than what was reported with US Hispanics. Some age and gender associated bias of the mutation frequency were observed with the study population, the reason for which is unclear at present

Gamma radiation induced leukemia in ICRC strain of mice: a murine model closely simulating human disease for experimental chemotherapy.

We report here a murine model of transplantable lymphoblastic leukemia closely simulating human disease in albino mice of ICRC strain. Both male and female mice of this strain developed leukemia with high incidence (approximately 70%) following whole body exposure to 60Co Gamma Rays (Dose: 1.5 Gray/Week x4). The latent period for development of leukemia was six months. In the leukemic mice there is marked leucocytosis with presence of lymphoblasts in peripheral blood. These blasts infiltrate various organs like liver, spleen, kidney, lymph nodes, testes and brain, Neoplastic cells are T lymphoblasts expressing weak Thy 1.2 membrane antigen and found sensitive to anticancer drugs. Salient features of the murine model are described.