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S Rani

Publications and source records attributed to S Rani.

At least 37 records · Page 2Linked to original sources
PubMed1999

Light sensitivity of the photoperiodic response system in higher vertebrates: wavelength and intensity effects.

Most species use daily light in one way or the other in regulation of their short and/or long term activities. Light is perceived by pigment(s) present in the retinal (RP) and/or extra-retinal photoreceptors (ERPs). ERPs may be located at various sites in the body but in non-mammalian vertebrates they are found predominantly in the pineal body and hypothalamic region of the brain, Light radiations directly penetrate brain tissues to reach and stimulate the hypothalamic (deep-brain) photoreceptors. How does light information finally reach to the clock is not fully understood in many vertebrate groups? In mammals, however, the light information from the retina to the clock (the hypothalamic suprachiasmatic nuclei, SCN) is relayed through the retino-hypothalamic tract (RHT) which originates from the retinal ganglion cells, and through the geniculo-hypothalamic tract (GHT) which originates from the photically responsive cells of a portion of the lateral geniculate nucleus (LGN), called the intergeniculate leaflet (IGL). A response to light (the photoperiodic response) is the result of the interpretation of light information by the photoperiodic system. Apart from the duration, the animals use the gradual shifts in the intensity and wavelength of daily light to regulate their photoperiodic clock system. The wavelengths to which photoreceptors are maximally sensitive or the wavelengths which have greater access to the photoreceptors can induce a maximal response. There can also be differential effects of wavelength and intensity of light on circadian process(es) involved in the entrainment and induction of the photoperiodic clock. This may have some adaptive implications. Entrainment to daily light-dark (LD) cycle may be achieved at dawn or dusk, depending whether the animal is day- or night-active, when there is relatively low intensity of light. By contrast, photoperiodic induction in many species occurs during long days of spring and summer when plenty of daylight at higher intensity is available later in the day.

Animals↗
PubMed1997

Sphingosine 1-phosphate stimulates tyrosine phosphorylation of Crk.

The proto-oncogene molecule c-Crk plays a role in growth factor-induced activation of Ras. Sphingosine 1-phosphate (SPP), a metabolite of cellular sphingolipids, has previously been shown to play a role in growth factor receptor signaling (Olivera, A., and Spiegel, S. (1993) Nature 365, 557-560). SPP was found to strongly induce tyrosine phosphorylation of Crk, but not Shc, in NIH-3T3 parental, insulin-like growth factor-I receptor-overexpressing and Crk-overexpressing (3T3-Crk) fibroblasts. Sphingosine, a metabolic precursor of SPP, also produced a slight increase in tyrosine phosphorylation of Crk. In contrast, other sphingolipid metabolites including ceramide did not alter Crk tyrosine phosphorylation. Furthermore, Crk enhanced SPP-induced mitogenesis, as measured by SPP-stimulated [3H]thymidine incorporation in a manner proportional to the level of Crk expression in 3T3-Crk cells. This stimulation appears to be Ras-dependent, whereas SPP stimulation of MAP kinase activity is Ras-independent. These data indicate that SPP activates a tyrosine kinase that phosphorylates Crk and that Crk is a positive effector of SPP-induced mitogenesis.

3T3 Cells↗
PubMed1997

Impaired resistance to the development of toxoplasmic encephalitis in interleukin-6-deficient mice.

The role of interleukin-6 (IL-6) in the pathogenesis of toxoplasmic encephalitis (TE) was examined by using IL-6-targeted mutant (IL-6(-/-)) mice. At 4 and 8 weeks after infection with the ME49 strain of Toxoplasma gondii, significantly greater numbers of T. gondii cysts and areas of inflammation associated with tachyzoites were observed in brains of IL-6(-/-) mice than in those of control mice. Large areas of necrosis were observed only in brains of IL-6(-/-) mice. Tachyzoites were frequently detected in the areas of necrosis, suggesting that necrosis was caused by proliferation of the parasite. These results indicate that IL-6 is protective against development of TE by preventing formation of T. gondii cysts and proliferation of tachyzoites in brains of infected mice. Whereas in brains of control mice, large numbers of inflammatory cells were always observed in areas where tachyzoites were detected, in brains of IL-6(-/-) mice, only small numbers of inflammatory cells were observed in many areas with tachyzoites. Lymphocyte preparations isolated from brains of infected control mice had significantly higher ratios of gamma/delta T cells and CD4+ alpha/beta T cells but lower ratios of CD8+ alpha/beta T cells compared to those of infected IL-6(-/-) mice. There were no differences in the ratios of these T-cell subsets in spleens between these mice. The amounts of mRNA for gamma interferon (IFN-gamma) detected by reverse transcriptase PCR were significantly smaller in brains of IL-6(-/-) mice than in those of control mice, whereas amounts of IL-10 mRNA were greater in the former than in the latter. IL-6 mRNA was detected only in infected control mice. The protective activity of IL-6 against development of TE appears to be through its ability to stimulate IFN-gamma production and induce infiltration and accumulation of different T-cell subsets in brains of infected mice.

Animals↗
PubMed1996

Effects of wavelength and intensity of light in initiation of body fattening and gonadal growth in a migratory bunting under complete and skeleton photoperiods.

A series of experiments investigated the effects of wavelength and intensity of light in initiation of body fattening (gain in body weight) and gonadal growth in migratory blackheaded bunting under complete and skeleton photoperiods. Using fluorescent light at an intensity approximately 700 lx, the first experiment compared the inductiveness of a complete (13 h continuous light coupled with 11 h darkness; 13L:11D) and a skeleton (two light pulses of 6 and 1 h at 6 h apart; 6L:6D:1L:11D) photoperiod. Observations at the beginning and after 3, 8, 10, and 13 weeks of the treatment indicated that both photoperiods were fully inductive but that birds under 13L photoperiod fattened and lost body weight significantly earlier than birds under skeleton photoperiod. In the second experiment, bunting were subjected to 13L:11D (L = 100 lx; D = 0 lx) of white, green (528 nm), and red (654 nm) light for a period of 5 weeks. Birds gained weight and testes grew in all groups except for an inconsistent fattening response in the white light group. The third experiment tested if the inductive effects of 1-h light pulse in a skeleton photoperiod were intensity dependent. Groups of bunting were exposed to 6L:6D:1L:11D (intensity of 1-h white light pulse = 2, 10, 50, or 100 lux) and examined at the beginning and after 3 and 8 weeks of the treatment. Photoinduction occurred at a slower rate and only at 50- and 100-lx intensities. The fourth experiment was similar to the third in design but it employed 1-h light pulse of two different wavelengths (green = 528 nm, and red = 654 nm) at 50- and 100-lx intensities. Birds fattened and testes grew only under red light. The last experiment varied the wavelength and intensity of the first (6 h) light pulse of the skeleton photoperiod (6L:6D:1L:11D): 6-h entraining light pulse of white, green (528 nm), or red (654 nm) colour at 10- or 50-lx intensity was used with 1-h inducing light pulse of white light at approximately 700-lx intensity. Testes grew in all groups but significant fattening occurred only in birds entrained to 50-lx light intensity. These results indicate i) the dissociation of body weight and gonadal responses, in the sense that the timing of photostimulation and/or magnitude of photoperiod-induced body weight and testicular responses differed under various photoperiodic manipulations, and ii) the circadian processes involved in photoperiod-induced responses have differential spectral and intensity sensitivity.

Animals↗
PubMed1996

Religion, ethnicity and obsessive-compulsive disorder.

Obsessive-compulsive disorder (OCD) is seen in many contrasting cultures but it is not known if the form of the disorder varies between these cultures. There have been anecdotal case reports where religion appeared to play a significant aetiological role in the disorder but the relationship between religion and OCD has not previously been systematically studied. This study was a retrospective, casenote study comparing the country of birth and religious affiliation of three groups of 50 patients. Its aim was to investigate the aetiological role played by religion in the development of OCD. The groups were patients with OCD from a specialist behavioural-cognitive unit, patients assessed in a specialist psycho-dynamic psychotherapy department and patients attending a general adult psychiatry outpatient department. More patients with OCD affiliated themselves with a religion as opposed to either of the other two groups. This difference disappeared when the type of religion was taken into account so that no conclusive relationship between OCD and religion could be identified. The findings do not diminish the importance of religion in the development of OCD in some individuals and suggest that future research in this area should include examination of the rigidity of upbringing and personal perception of the experience of strict rules or imposed religious practices.

Adolescent↗
PubMed1996

Development of indicators for cephamycin bioassay.

Several species of bacteria have been tested, for their sensitivity to cephamycin C and other beta-lactam antibiotics with a view to develop an indicator system for identification and quantitation of cephamycin. During the study, a mutant derived from E. coli K 802, exhibited a 10-fold increased sensitivity to cephamycin C than E. coli ESS (reference strain)1,2 and was designated as supersensitive E. coli K 8025. Another interesting feature observed during the investigation was that a strain of Serratia, showed a high degree of resistance to penicillins and cephalosporins however, it was sensitive to cephamycin and its derivative. It has been suggested that E. coli K 8025 and Serratia would serve as good indicator organisms for detection and quantitation of cephamycin.

Anti-Bacterial Agents↗
PubMed1996

Splenic lymphocytes with circulating villous lymphocytes--a case report.

A 25 years old male presented with hepatomegaly splenomegaly and fever. He was diagnosed as splenic lymphoma with circulating villous lymphocytes (SLVL) on morphology, cytochemistry and immunocytochemistry performed on peripheral blood and bone marrow smears. Case is being presented because of rarity and unusual presentation at young age.

Adult↗
PubMed1993

Expression of differentially phosphorylated Rb and mutant p53 proteins in myeloid leukemia cell lines.

We studied the structure and expression of Rb and p53 genes in six myeloid leukemia cell lines (HL-60, KBM3, K562, KBM5, EM2, KBM7) in the light of the published reports that structural abnormalities of these genes are rarely seen in leukemic cells and also a recent finding that Rb gene expression can be regulated by the p53 protein. Except for HL-60 cells which have a truncated p53 gene, none of the other cell lines revealed any gross structural abnormalities in the Rb and p53 genes. KBM3, KBM5 and EM-2 expressed lower levels of Rb mRNA than HL-60, K562 and KBM7. The amount of Rb protein was lowest in KBM3 cells and in this and two other cell lines (KBM5, KBM7) Rb was markedly hypophosphorylated compared to the other three cell lines. HL-60 and K562 did not express p53 m-RNA, while the other four cell lines all expressed high levels of mutant p53 protein. Thus even in the absence of gross structural alterations, subtle abnormalities in the expression pattern of Rb and p53 genes occur in myeloid leukemia cells.

Base Sequence↗
PubMed1993

Marrow histomorphology and clinical staging of chronic lymphocytic leukemia--a rare disease in India: experience with 26 cases.

Chronic Lymphocytic Leukemia is a relatively uncommon hemopoietic malignancy in the Indian subcontinent. We have made an attempt to correlate the morphology of the marrow with staging and clinical course of the disease in 26 cases. Four out of 6 cases in Stage A showed a nodular/interstitial marrow pattern, while 18 out of 20 cases of stage B and C demonstrated a mixed/diffuse involvement of marrow. Cases showing a nodular/interstitial pattern had a relatively benign clinical course even without chemotherapy, while patients with diffuse/mixed marrow pattern required chemotherapy. Trephine histological pattern was found to be a good prognosticator and was useful in segregating cases requiring chemotherapy from those which do not.

Aged↗
PubMed1992

Detection of extrachromosomal circular DNA sequences from tumor cells by an alkaline lysis, Alu-polymerase chain reaction technique.

Extrachromosomal circular DNAs ranging in size from submicroscopic molecules of approximately 100 kb to cytogenetically resolvable structures of 1000+ kb called minute and double-minute chromosomes have been shown to harbor amplified genes in primary tumor cells, tumor cell lines, and drug-resistant cells grown in vitro. The presence of these molecules in transformed and malignant cells trends to reflect genetic instability and also suggests that role in tumor progression. Using a colon carcinoma cell line, we developed a technique to detect extrachromosomal circular DNA-specific sequences by Alu-polymerase chain reaction. Circular DNA was enriched by selective alkaline denaturation of genomic DNA. We have successfully performed this procedure with a minimum of 5 x 10(5) cells. The technique does not require any prior knowledge of the sequences located on the covalent circular DNA molecules for their detection. The procedure should be useful as a routine screen of primary tumor cells for the presence of extrachromosomal circular DNA and should permit the preparation of specific probes ot aid in their detailed characterizations.

Base Sequence↗
PubMed1992

Role of cell growth factor (interleukin-2) and its receptors in carcinoma cervix patients.

Host immunity plays an important role in neoplasia. Neoplastic activity is known to correspond with the disturbances in immunological mechanisms. T-lymphocytes DNA replication and mitosis are determined by a critical threshold of signals generated by the interaction between interleukin-2 (IL-2) and its receptors. So we planned to study the level of IL-2 in carcinoma cervix patients. Twenty healthy (normal) and fifty carcinoma cervix patients were investigated. The level of IL-2 was estimated by thymidine incorporation [Anderson et al., Eur. J. Immun. 9 (1979) 581-587]. A remarkable decrease in concentration of IL-2 in serum of the patients (mean = 21.62 U/100 microliters) when compared with normal healthy individuals (36.86 U/100 microliters). Immunotherapy in the form of IL-2 can be suggested in such patients.

Adult↗
PubMed1990

A variant form of hairy cell leukemia resistant to alpha-interferon: clinical and phenotypic characteristics of 17 patients.

We describe the clinical and laboratory features of 17 adult patients with a variant form of hairy cell leukemia (HCL-V) studied over the last 7 years. The main findings were: splenomegaly, moderate anemia, thrombocytopenia, and a raised white blood cell count (median 116 x 10(9)/L; range 15 to 482). The circulating lymphoid cells had abundant villous cytoplasm and a round, occasionally bilobed nucleus, with a prominent nucleolus. Monocytopenia, a feature of typical HCL, was not seen; neither was tartrate-resistant acid phosphatase demonstrated in eight cases tested. HCL-V cells had a mature B-cell phenotype: CD19+, CD20+, CD22+, FMC7+, CD11c+, CD10-, CD5-, with light chain isotope restriction in 15 cases. In contrast to typical hairy cells, HCL-V cells were negative with the monoclonal antibodies anti-HC2 and anti-TAC (CD25). Immunoglobulin (Ig) was not detected in two cases and IgG was expressed in the cell membrane of 73% of cases. Bone marrow histology was different from HCL, showing interstitial infiltration by cells clumped together and a moderate amount of reticulin, but the spleen showed the typical red pulp expansion of HCL. HCL-V patients did not respond to splenectomy (5 of 7) or alpha-interferon (7 of 7); 2 of 3 patients had a partial response to 2'deoxycoformycin. The clinical course was benign with 15 patients alive with a median survival greater than 4 years. We confirm that HCL-V is a distinct clinico-pathologic entity with intermediate features between HCL and B-prolymphocytic leukemia.

Aged↗