Fetal antigen retained by mature neurons and ependyma studied with a monoclonal antibody (6B9)

A mouse monoclonal antibody (MAb 6B9, isotype IgM) was raised against autopsy tissue samples from the central nervous system (CNS) of multiple sclerosis (MS) patients. By immunofluorescence microscopy, MAb 6B9 intensely stains most or all cells in fetal rats. However, MAb 6B9 differentially stains various cell types in adult rats. Neurons, ependymal cells, and adrenal chromaffin cells are stained intensely, whereas astrocytes and oligodendrocytes are not stained. The 6B9-reactive antigen (6B9 antigen) is sensitive to periodic acid, but insensitive to treatment with protease, RNase, or hyaluronidase. Results from immunofluorescence microscopy on semithin sections and cultured neuroblastoma cells indicate that 6B9 antigen is intracellular. This is supported by immunoelectron microscopy, where labeling for 6B9 antigen appears in the cytoplasm distinct from any identifiable organelle. Further studies on 6B9 antigen should reveal its chemical nature as well as the significance of developmental changes in its distribution.     

Genetic immunization with GPI-anchored anthrax protective antigen raises combined CD1d- and MHC II-restricted antibody responses by natural killer T cell-mediated help

Studies have demonstrated that lipid rafts ultimately regulate the endocytosis of anthrax toxin via clathrin dependent pathway. Interestingly, GPI-anchored protein rich rafts have also been shown to be transported down to the endocytic pathway to reducing late endosomes. Taking advantage of this parallelism, we tried translating the anthrax toxin natural intoxication mechanism by administering a DNA chimera that encoded protective antigen attached to a mammalian GPI-anchor sequence at its C-terminus (pGPI-PA63). We also designed a chimera that had an additional N-terminal TPA leader sequence (pTPA.GPI-PA63) with an aim to target GPI-PA63 to ER where new CD1 molecules are synthesized. Analysis of antibody titers demonstrated successful priming and potential IgG titers after the first boost. In vitro cell proliferation studies in the presence of GPI-attached PA63 peptides revealed that there was a clonal expansion of CD4⁺ NK1.1⁺ helper T cell population which rapidly produced IL-4 in response to T cell receptor ligation. These cells provided direct B cell help that aided IgG formation. Effector responses generated by NKT cells were found to be MHC II-independent and CD1d-restricted. In addition, the group pTPA.GPI-PA63 also displayed low magnitude MHC-II restricted (CD1d-independent) NKT cell and CD4⁺ T cell helper responses in response to non-GPI attached PA63 peptides which overall resulted in the heightened responses seen for this group. Importantly, DNA vaccination mediated the generation of high avidity neutralizing antibodies that mediated protection against lethal toxin challenge.     

Melatonin rhythms and pineal structure in a tropical bat, Anoura geoffroyi, that does not use photoperiod to regulate seasonal reproduction

Abstract: It has been hypothesized that pineal structure and function might differ between temperate zone and tropical species of mammals because of lower amplitudes of seasonal change in photoperiod and, in some areas, less seasonal climatic variation. Anoura geoffroyi produce a single offspring in November or December of each year on the Caribbean island of Trinidad, at 10°N latitude in the deep tropics. Previous work has shown that this population lacks reproductive responses to photoperiod, and must be enforcing seasonal breeding using a non-photoperiodic cue. Anoura geoffroyi have a minute, thin, and rod-like pineal gland. Throughout much of its length, the pineal courses irregularly within the ventrolateral wall of the great cerebral vein. This intimate relationship may have functional implications. Despite having a very small pineal gland, this species produced a nocturnal rise in serum melatonin. Serum melatonin levels in most individuals were below or near undetectable levels during the light period and rose to a peak averaging 100 pg/ml in the last third of the dark period. Our results indicate that, although the pineal gland of A. geoffroyi is extremely small, serum melatonin levels are comparable to those of other mammals.     

Effect of air pollution on peak expiratory flow rate variability.

Exposure to air pollution affects pulmonary functions adversely. Effect of exposure to pollution on diurnal variation of peak flow was assessed in healthy students. Three hundred healthy age-matched nonsmoker students were studied. They were categorized into two groups on the basis of their residence: commuters and living on campus. Peak expiratory flow (PEF) recordings were made twice daily for 2 days with the Pink City Flow Meter. The measurement was then used to calculate for each subject the amplitude percentage mean, which is an index for expressing PEF variability for epidemiological purposes (Higgins BG, Britton JR, Chinns Jones TD, Jenkinson D, Burnery PG, Tattersfield AE. Distribution of peak expiratory flow variability in a population sample. Am Rev Respir Dis 1989; 140:1368-1372). Air pollution parameters were quantified by measurement of sulfur dioxide (SO2), oxides of nitrogen (NO2), carbon monoxide (CO), and respirable suspended particulate matter (RSPM) in the ambient air at the campus and on the roadside. The mean values of PEF variability (amplitude percent mean) in the students living on campus and in the commuters were 5.7 +/- 3.2 and 11 +/- 3.6, respectively (P < .05). Among the commuters, maximum number of subjects showed amplitude percentage mean PEFR at the higher end of variability distribution, as compared to the students living on campus, among whom the majority of subjects fell in the lower ranges of variability distribution. The ambient air quality parameters, namely SO2, NO2, CO, and RSPM were significantly lower on the campus. It can be concluded that long-term periodic exposure to air pollution can lead to increased PEF variability even in healthy subjects. Measurement of PEF variability may prove to be a simple test to measure effect of air pollution in healthy subjects.     

Radiofrequency tissue ablation: an early Indian experience.

INTRODUCTION: Radiofrequency (RF) tissue ablation has been tried safely and effectively in the West as percutaneous local tissue ablation therapy. We present our experience with this technique in malignant lesions. METHODS: RF tumor ablation was done using an RF generator (Berchtold; Germany) generating 35-50 RF watts of power output. The RF needle was placed in the tumor under image guidance (n = 22) or at open surgery (n = 1). Around 1500 watts/cm3 RF energy was delivered to the tumor. Over 21 months, 23 patients underwent the procedure for 73 lesions, including metastatic liver lesions (n = 21) and locally advanced inoperable carcinoma of pancreas (n = 2). RESULTS: All lesions less than 3 cm in size (n = 15) and 39% of lesions 3-4 cm in size (17/44) had complete necrosis. Residual tumor was seen in 27/44 lesions (61%) 3-4 cm in size and in all 14 lesions more than 4 cm in size. There was no mortality or major morbidity. There were two minor complications (ascites 1, pleural effusion 1). Of 21 patients treated for liver metastases, 10 are still alive (6-month survival 19/21 [90%] and 12-month survival 11/17 [64.7%]). Only 2 of 32 (6.2%) lesions with complete necrosis had local recurrence. CONCLUSION: RF tumor ablation is a safe and effective local tissue ablative method in Indian patients.     

Inhibition kinetics of human kidney aldose and aldehyde reductases by aldose reductase inhibitors

Kinetic patterns of inhibition of homogenous human kidney aldose reductase (AR, EC 1.1.1.21) and aldehyde reductase II (AR II, EC 1.1.1.19) by statil, ICI 105552 [1-(3,4-dichlorobenzyl)-3-methyl-1,2-dihydro-2-oxoquinol-4-yl acetic acid], tolrestat, alrestatin, chromone carboxylic acid (CCA), quercetin, phenobarbital and sorbinil were studied. On the basis of the kinetic nature of inhibition, the inhibitors were classified into four distinct categories. For aldose reductase, sorbinil and phenobarbital were noncompetitive (NC; category I) and CCA and alrestatin were uncompetitive (UC; category II) to both the aldehyde substrate and NADPH. Quercetin and ICI 105552 were NC to the aldehyde and UC to NADPH (category III) and tolrestat and statil were UC to the aldehyde and NC to NADPH (category IV). For AR II, sorbinil and alrestatin were category I inhibitors, ICI 105552 and statil belong to category II, phenobarbital, tolrestat and CCA to category III, and quercetin to category IV. To determine the specificity of inhibition, the ratios of the inhibition constants (Kii) for AR and AR II were calculated. A lower ratio indicates greater specificity. With aldehyde as the varied substrate the specificity ratios were: statil less than ICI 105552 less than alrestatin less than tolrestat less than quercetin less than CCA less than sorbinil less than phenobarbital, and with NADPH as the varied substrate, ICI 105552 less than statil less than alrestatin less than tolrestat less than quercetin less than CCA less than sorbinil less than phenobarbital. For AR, double-inhibition plots generated for one inhibitor from each kinetic category versus sorbinil showed that AR inhibitors of categories I-III bind to the same site on the protein molecule as sorbinil. However, tolrestat seemed to bind to a site different from the sorbinil binding site. For AR II, inhibitors from all the four categories appeared to bind to the same inhibitor binding site.