Regulation of NK cell function in vivo by the dose of tumour transplanted in the peritoneum

Antigen dose is known to regulate T cell activation and anergy. Similarly, dose of antigen also regulates NK cell lytic potential and phenotype development. Resident peritoneal cells of rat contain a small population of NK and NKT cells. Inoculation of AK-5 tumour cells intraperitoneally modulate the cytotoxic function of NK and NKT cells present in the peritoneal exudate cells (PEC) in a dose dependent manner. Low dose of tumour causes activation of NK and NKT cell cytotoxic function and enhanced NK and NKT cell population in PEC, whereas, high doses of tumour cause inactivation of NK and NKT cell cytotoxic function and depletion of the two sub-populations in the peritoneum. Different doses of tumour inoculation in the peritoneal cavity did not suppress the cytotoxic function of NK cells from spleen suggesting that a direct interaction between NK cells and tumour cells is required for the suppression of NK cell cytotoxic function. Tumour inoculation induced secretion of IL-2, IL-12, IFN-gamma and TNF-alpha by tumour infiltrating mononuclear cells (TIM) in ascitic fluid as well as in serum. The levels of IL-2, IL-12, IFN-gamma and TNF-alpha secretion were higher in animals, which rejected tumours as compared with the animals that failed to reject the tumours. Injection of anti IL-12 and anti IFN-gamma antibody reduced the survival rate of tumour injected animals, however, anti IL-2 antibody had no effect on the survival of animals. Following incubation with AK-5 tumour cells, activated NK cells upregulated perform expression, whereas, there was upregulation of CD95 expression in inactivated NK cells.     

Increased Levels of Inflammatory Mediators in Children and Adults Infected with Vibrio cholerae O1 and O139

Investigations were carried out to study the production of factors associated with the innate immune response in the systemic and mucosal compartments in adults and children infected with Vibrio cholerae O1 and V. cholerae O139. The levels of nonspecific mediators of the innate defense system, i.e., prostaglandin E₂ (PGE₂), leukotriene B₄ (LTB₄), and lactoferrin (Lf), as well as myeloperoxidase (MPO), were elevated at the acute stage of the disease in stools obtained from both O1- and O139-infected adults and children. In the systemic compartment, the levels of Lf were increased after onset of disease, which in children remained elevated up to convalescence compared to the healthy controls. Increased concentrations of C-reactive protein were seen in the sera of adult cholera patients at the acute stage of infection. Elevated levels of the nitric oxide (NO^·) metabolites (nitrite and nitrate [NO₂⁻ and NO₃⁻]) were detected in plasma but not in urine. The activity of the scavenger of reactive oxygen species, superoxide dismutase, was higher in the plasma of adults immediately after the onset of disease, suggesting that an active scavenging of reactive oxygen species was taking place. The concentration of 8-iso-prostaglandin F_2α remained unchanged in the systemic and mucosal compartments in the study subjects. After the recovery of patients from cholera, the concentration of the majority of the metabolites decreased to baseline levels by day 30 after the onset of infection. Immunohistochemical staining showed increased tissue expression of MPO, Lf, and inducible nitric oxide synthase at the acute stage in the duodenal biopsies of adults and rectal biopsies obtained from children with cholera. Very little difference was seen in the levels of the different inflammatory mediators in patients infected with V. cholerae O1 or the encapsulated V. cholerae O139. In summary, these results suggest that elevated concentrations of Lf, MPO, PGE₂, LTB₄, and NO^·, as well as other metabolites, during the acute stage of the disease indicate that the innate defense system, as well as the inflammatory process, is activated in both adults and pediatric patients infected with V. cholerae O1 and O139.     

Fine-needle aspiration cytology diagnosis of tuberculosis

Fine-needle aspiration cytology of lymph nodes and extranodal swellings in 160 cases showed granulomatous reaction with or without caseation necrosis in 83%. The material was acellular or predominantly composed of necrotic material, polymorphs, and lymphocytes in 17%. The age of the patient ranged from 1.5 to 72 yr. The male to female ratio was 1:1.3. Acid-fast bacilli (AFB) could be demonstrated in 40.6% of cases. In cases associated with cellular reaction and necrosis. AFB positivity was 50.0%, while it was 66.7% in cases with acellular necrotic material.     

Characterization and physical map of choleraphage φ149 DNA

Choleraphage φ149 DNA is a linear double-stranded molecule 69 × 10⁶ Da or 104 kilobase pairs (kbp). From restriction enzyme analysis, it has been concluded that the DNA is circularly permuted. There are at least three S1 nuclease-sensitive sites along the length of the molecule. These sites represent single-strand interruptions repairable by T4 DNA ligase. A physical map of the DNA has been constructed using the restriction endonucleases BamH1 and BglII.     

Infection with an extended-spectrum beta-lactamase-producing strain of Serratia marcescens following tongue reconstruction

We report a case of postsurgical wound infection of polymicrobial etiology caused by Serratia marcescens and Pseudomonas aeruginosa following the use of a radial forearm free flap for oncological tongue reconstruction. S. marcescens was a producer of SHV-12 extended-spectrum beta-lactamase (ESBL). This is the first report from India of this ESBL. S. marcescens and P. aeruginosa were resistant to the empirical perioperative antibiotics administered. Delay in the recognition of the type of infection and in the institution of appropriate therapy resulted in total loss of the free flap.