Backbone dynamics and refined solution structure of the N-terminal domain of DNA polymerase beta. Correlation with DNA binding and dRP lyase activity

Mammalian DNA polymerase beta functions in the base excision DNA repair pathway filling in short patches (1-5 nt) in damaged DNA and removing deoxyribose 5'-phosphate from the 5'-side of damaged DNA. The backbone dynamics and the refined solution structure of the N-terminal domain of beta-Pol have been characterized in order to establish the potential contribution(s) of backbone motion to the DNA binding and deoxyribose 5'-phosphate lyase function of this domain. The N-terminal domain is formed from four helices packed as two antiparallel pairs with a 60 degrees crossing between the pairs. The RMSD of the NMR conformers (residues 13-80) is 0.37 A for the backbone heavy atoms and 0.78 A for all heavy atoms. NMR characterization of the binding site(s) for a ssDNA-5mer, ssDNA-8mer, ssDNA-9mer, and dsDNA-12mer shows a consensus surface for the binding of these various DNA oligomers, that surrounds and includes the deoxyribose 5'-phosphate lyase active site region. Connection segments between helices 1 and 2 and between helices 3 and 4 each contribute to DNA binding. Helix-3-turn-helix-4 forms a helix-hairpin-helix motif. The highly conserved hairpin sequence (LPGVG) displays a significant degree of picosecond time-scale motion within the backbone, that is possibly important for DNA binding at the phosphodiester backbone. An Omega-loop connecting helices 1 and 2 and helix-2 itself display significant exchange contributions (R(ex)) at the backbone amides due to apparent conformational type motion on a millisecond time-scale. This motion is likely important in allowing the Omega-loop and helix-2 to shift toward, and productively interact with, gapped DNA. The deoxyribose 5'-phosphate lyase catalytic residues that include K72 which forms the Schiff's base, Y39 which is postulated to promote proton transfer to the aldehyde, and K35 which assists in phosphate elimination, show highly restricted backbone motion. H34, which apparently participates in detection of the abasic site hole and assists in the opening of the hemiacetal, shows conformational exchange.

FEN1 stimulation of DNA polymerase beta mediates an excision step in mammalian long patch base excision repair

In mammalian cells, single-base lesions, such as uracil and abasic sites, appear to be repaired by at least two base excision repair (BER) subpathways: "single-nucleotide BER" requiring DNA synthesis of just one nucleotide and "long patch BER" requiring multi-nucleotide DNA synthesis. In single-nucleotide BER, DNA polymerase beta (beta-pol) accounts for both gap filling DNA synthesis and removal of the 5'-deoxyribose phosphate (dRP) of the abasic site, whereas the involvement of various DNA polymerases in long patch BER is less well understood. Recently, we found that beta-pol plays a role in mammalian cell extract-mediated long patch BER, in that formation of a key excision product, 5'-dRP-trinucleotide (5'-dRP-N(3)), is dependent upon beta-pol (Dianov, G. L., Prasad, R., Wilson, S. H., and Bohr, V.A. (1999) J. Biol. Chem. 274, 13741-13743). The structure-specific endonuclease flap endonuclease 1 (FEN1) has also been suggested to be involved in long patch BER excision. Here, we demonstrate by immunodepletion experiments that 5'-dRP-N(3) excision in long patch BER of uracil-DNA in a human lymphoid cell extract is, indeed, dependent upon FEN1. Next, we reconstituted the excision step of long patch BER using purified human proteins and an oligonucleotide substrate with 5'-dRP at the margin of a one-nucleotide gap. Formation of the excision product 5'-dRP-N(3) was dependent upon both strand displacement DNA synthesis by beta-pol and FEN1 excision. FEN1 stimulated strand displacement DNA synthesis of beta-pol. FEN1 acting either alone, or without DNA synthesis by beta-pol, produced a two-nucleotide excision product, 5'-dRP-N(1), but not 5'-dRP-N(3). These results demonstrate that human FEN1 and beta-pol can cooperate in long patch BER excision and specify the predominant excision product seen with a cell extract.

8-oxodGTP incorporation by DNA polymerase beta is modified by active-site residue Asn279

To understand how the active site of a DNA polymerase might modulate the coding of 8-oxo-7,8-dihydrodeoxyguanine (8-oxodG), we performed steady-state kinetic analyses using wild-type DNA polymerase beta (pol beta) and two active-site mutants. We compared the coding of these polymerases by calculating the ratio of efficiencies for incorporation of dATP and dCTP opposite 8-oxodG and for incorporation of 8-oxodGTP opposite dA and dC. For wild-type pol beta, there is a 2:1 preference for incorporation of dCTP over dATP opposite 8-oxodG using a 5'-phosphorylated 4-base gap substrate. Mutation of either Asn279 or Arg283 to alanine has almost no effect on the ratio. 8-OxodGTP is preferentially incorporated opposite a template dA (24:1) by wild-type pol beta; mutation of Asn279 to alanine results dramatic change whereby there is preferential incorporation of 8-oxodGTP opposite dC (14:1). This suggests that interactions of 8-oxodGTP with Asn279 in the polymerase active site may alter the conformation of 8-oxodGTP and therefore alter its misincorporation.

Interleukin-11 enhances small intestine absorptive function and mucosal mass after intestinal adaptation

BACKGROUND/PURPOSE

Interleukin-11 (IL-11) recently has been shown to enhance mucosal mass after massive small bowel resection (MSBR). However, enhanced mucosal mass may not correlate with increased substrate absorption. This study was designed to examine the effect of systemic administration of increasing doses of IL-11 on small intestine absorptive function and mucosal mass after MSBR.

METHODS

Twenty-five Sprague-Dawley rats underwent an 80% small bowel resection and end-to-end jejunoileal anastomosis. Seven days after resection, all rats had placement of a jugular venous catheter connected to a subcutaneously placed osmotic pump. The rats were divided into 5 groups based on the content of the pump: group 1 (control, n = 5) received 0.1% bovine serum albumin (BSA) and groups 2 through 5 (n = 5 each) received IL-11 at 250, 500, 750, and 1,000 microg/kg/d, respectively. After a 14-day infusion period, [14C] galactose and [14C] glycine absorption was measured using an in vivo closed-recirculation technique. Mucosal DNA content also was determined for each group. Statistical analysis was performed by analysis of variance and expressed as mean +/-SEM.

RESULTS

IL-11 administered at 250 microg/kg/d, a dose used in previous studies, did not significantly affect substrate absorption. However, compared with the control group, administration of higher doses of IL-11 produced a significant increase in substrate absorption and mucosal mass. The dose of IL-11 producing the overall optimal response based on the parameters measured (galactose absorption, 72% increase over control; glycine absorption, 112% increase over control; and DNA content, 98% increase over control) was 750 microg/kg/d.

CONCLUSIONS

In addition to an increase in mucosal mass, these data show for the first time that IL-11 enhances absorptive function beyond the normal adaptive response after MSBR. Furthermore, the maximum effect of IL-11 on absorptive function was shown at 750 microg/kg/d, which is 3 times the dose used in previously reported studies. This study suggests that IL-11 may be useful clinically in patients with inadequate intestinal function.

Glucagonlike peptide-2 analogue enhances intestinal mucosal mass after ischemia and reperfusion

BACKGROUND/PURPOSE

Glucagonlike peptide-2 (GLP-2), a product of the posttranslational processing of proglucagon, has been shown to enhance mucosal mass and function in both normal intestine and in the residual intestine after massive small bowel resection. This study was designed to determine if a synthetic, protease-resistant analogue of GLP-2 (GLP-2alpha) can enhance mucosal mass in small intestine after ischemia and reperfusion (I/R) injury.

METHODS

Ten young adult male Sprague-Dawley rats underwent laparotomy and superior mesenteric artery occlusion for a period of 40 minutes. During this period of ischemia, each rat underwent placement of a jugular venous catheter that was connected to a subcutaneously placed osmotic pump designed to deliver its contents over 3 days. The rats were divided into 2 groups based on the contents of the pumps: group 1, saline at 1 microL/h (n = 6) and group 2, GLP-2alpha at 100 microg/kg/d (n = 4). Three days after insertion of the pumps the small intestine was harvested from the surviving rats for determination of mucosal DNA and protein content. Statistical analysis was performed using unpaired Student's t test.

RESULTS

After I/R injury to the small intestine, a 3-day systemic infusion of GLP-2alpha significantly increased mucosal DNA content 41% (P<.05) and mucosal protein content 60% (P<.05) when compared with saline-treated controls. In addition, infusion of GLP-2alpha reduced mortality from 50% to 25%.

CONCLUSIONS

These data show for the first time that GLP-2alpha enhances mucosal mass following I/R injury to the small intestine. GLP-2alpha may be of benefit to patients with intestinal ischemia syndromes such as necrotizing enterocolitis and midgut volvulus.

Protection against methylation-induced cytotoxicity by DNA polymerase beta-dependent long patch base excision repair

Using a plasmid-based uracil-containing DNA substrate, we found that the long patch base excision repair (BER) activity of a wild-type mouse fibroblast extract was partially inhibited by an antibody to DNA polymerase beta (beta-pol). This suggests that beta-pol participates in long patch BER, in addition to single-nucleotide BER. In single-nucleotide BER, the deoxyribose phosphate (dRP) in the abasic site is removed by the lyase activity of beta-pol. Methoxyamine (MX) can react with the aldehyde of an abasic site, making it refractory to the beta-elimination step of the dRP lyase mechanism, thus blocking single-nucleotide BER. MX exposure sensitizes wild-type, but not beta-pol null mouse embryonic fibroblasts, to the cytotoxic effects of methyl methanesulfonate (MMS) and methylnitrosourea. Expression of beta-pol in the null cells restores the ability of MX to modulate sensitivity to MMS. The beta-pol null cells are known to be hypersensitive to MMS and methylnitrosourea, and in the presence of MX (i.e. under conditions where single-nucleotide BER is blocked) the null cells are still considerably more sensitive than wild-type. The data are consistent with a role of beta-pol in long patch BER, which helps protect cells against methylation damage-induced cytotoxicity.

Tumor implantation at the flap donor site: a case report

The genesis of cancer and its variable patterns of spread have been theorized and debated upon for decades. Recurrences, both local and metastatic, are dreaded by both the patient as well as the surgeon. An interesting case of tumor implantation at the flap donor site was noted in a patient who underwent a primary flap reconstruction for cancer of the cheek. The details of the case and theories regarding tumor implantation have been enumerated in this report.

Molecular cloning and functional characterisation of a glucose transporter, CaHGT1, of Candida albicans

We have cloned the first glucose transporter CaHGT1 (Candida albicans high-affinity glucose transporter) of a pathogenic yeast, Candida albicans. The DNA sequence (GenBank accession number Y16834) analysis revealed an ORF encoding a novel protein of 545 amino acids with a predicted molecular mass of 60.67 kDa. The putative protein with 12 transmembrane domains has 51% identity with Kluyveromyces lactis high-affinity glucose transporter, HGT1. The protein signatures which are conserved and distinctive of the sugar transporters belonging to the major facilitator superfamily (MFS) were also found in CaHgt1p. When heterologously expressed, the ORF functionally complemented a mutant strain of Saccharomyces cerevisiae RE700A which was deleted in seven hexose transporter genes and thus was unable to grow or transport glucose. The expression of CaHGT1 in C. albicans showed a transcript of 1.6 kb which was enhanced in response to the human steroid hormone progesterone. Interestingly, the transcript levels were also enhanced in the presence of drugs, e.g. cycloheximide, chloramphenicol and benomyl. The results suggest that CaHGT1, which encodes a MFS protein, could be linked to the drug resistance phenomenon in C. albicans.

CDR1, a multidrug resistance gene from Candida albicans, contains multiple regulatory domains in its promoter and the distal AP-1 element mediates its induction by miconazole

We previously demonstrated that the CDR1 gene, encoding a multidrug transporter in Candida albicans, is differentially upregulated by various drugs and steroids. In order to get an insight into the molecular basis of the induction of this gene we analyzed its promoter region. The transcription start site was mapped to 63 nucleotides upstream of the initiating ATG. Reporter assays revealed the presence of four upstream activating and four upstream repressing sequence domains along the entire promoter. Like the native gene, promoter-luciferase recombinants showed enhanced activity in response to various stresses like drugs, human steroid hormones and heavy metals. Mutational analysis demonstrated that while the proximal promoter (-345/+1) contains all the regulatory domains required for its induction by various other stresses, the miconazole response is mediated via the distal promoter (-857/-1147), harboring an AP-1 site. The involvement of the AP-1 element in mediating the latter effect was evident by an increase in AP-1 binding activity following miconazole treatment.

Efficacy of curcumin in the management of chronic anterior uveitis

Curcumin, obtained from rhizomes of Curcuma longa, was administered orally to patients suffering from chronic anterior uveitis (CAU) at a dose of 375 mg three times a day for 12 weeks. Of 53 patients enrolled, 32 completed the 12-week study. They were divided into two groups: one group of 18 patients received curcumin alone, whereas the other group of 14 patients, who had a strong PPD reaction, in addition received antitubercular treatment. The patients in both the groups started improving after 2 weeks of treatment. All the patients who received curcumin alone improved, whereas the group receiving antitubercular therapy along with curcumin had a response rate of 86%. Follow up of all the patients for the next 3 years indicated a recurrence rate of 55% in the first group and of 36% in the second group. Four of 18 (22%) patients in the first group and 3 of 14 patients (21%) in the second group lost their vision in the follow up period due to various complications in the eyes, e.g. vitritis, macular oedema, central venous block, cataract formation, glaucomatous optic nerve damage etc. None of the patients reported any side effect of the drug. The efficacy of curcumin and recurrences following treatment are comparable to corticosteroid therapy which is presently the only available standard treatment for this disease. The lack of side effects with curcumin is its greatest advantage compared with corticosteroids. A double blind multi-centric clinical trial with this drug in CAU is highly desirable to further validate the results of the present study.

Activation of Glut1 glucose transporter in response to inhibition of oxidative phosphorylation

We have previously shown that exposure of Clone 9 cells to hypoxia, cyanide, or azide results in an acute stimulation of glucose transport that is largely mediated by "activation" of glucose transporter (Glut1) sites preexisting in the plasma membrane. However, it is not known whether inhibition of oxidative phosphorylation only at its terminal step, or at any of its steps, leads to the glucose transport response. Hence, the effect of azide (5 mM), rotenone (1 microM), rotenone (1 microM) plus thenoyltrifluoroacetone (TTFA) (5 microM), antimycin A (0.3 microM), dinitrophenol (0.25 mM), carbonyl cyanide m-chlorophenylhydrazone (CCCP) (2.5 microM), and oligomycin B (0.15 microM) on glucose transport was determined. All of the above agents elicited a similar approximately 4-fold stimulation of cytochalasin B (CB)-inhibitable 3-O-methyl glucose (3-OMG) uptake in Clone 9 cells. The stimulatory effect of azide on 3-OMG uptake was not inhibited by antioxidants 2-mercaptopropionyl glycine (1.2 mM) and 1,10-phenanthroline (40 microM), while, in contrast, the antioxidants attenuated the stimulation of glucose transport in response to 250 microM H(2)O(2) by approximately 50%. To differentiate between an increase in the number of functional Glut1 sites in the plasma membrane (in the absence of "translocation") versus an increase in the "intrinsic activity" of Glut1, the effect of azide on the energy of activation (E(a)) of glucose transport was measured. The E(a) was determined by measuring the rate of CB-inhibitable 3-OMG uptake at 24.0, 28.0, 35. 0, and 40 degrees C. The E(a) of control Clone 9 cells and of cells exposed to 10 mM azide for 2 h was 32,530 +/- 1830 and 31,220 +/- 600 J/mol, respectively (P > 0.1), while the rate of CB-inhibitable 3-OMG uptake was 9.3 +/- 0.7-fold higher in azide-treated cells. It is concluded that (i) inhibition of oxidative phosphorylation, at any of its steps, leads to a stimulation of glucose transport, and (ii) the mechanism of stimulation of glucose transport in response to azide appears to be predominately mediated by an apparent increase in the number of functional Glut1 sites in the plasma membrane (instead of an increase in their "intrinsic activity"), suggesting an "unmasking" mechanism.

Effects of candesartan cilexetil in patients with severe systemic hypertension. Candesartan Cilexetil Study Investigators

The efficacy, tolerability, and safety of the potent angiotensin II receptor blocker candesartan cilexetil were evaluated in 217 adult patients (68% men, 41% black) with severe systemic hypertension on background therapy with hydrochlorothiazide (HCTZ) in a 4-week, multicenter, randomized, double-blind, placebo-controlled study. Patients with sitting diastolic blood pressure (BP) > or =110 mm Hg during the placebo run-in received HCTZ 12.5 mg once daily for 1 week. Those with sitting diastolic BP >95 mm Hg after the HCTZ run-in were randomized (2:1) to receive candesartan cilexetil 8 mg once daily (n = 141) or placebo (n = 76), plus HCTZ 12.5 mg. After 1 week of double-blind treatment, patients with sitting diastolic BP > or =90 mm Hg were uptitrated to candesartan cilexetil 16 mg once daily or matching placebo, plus HCTZ 12.5 mg; 84% required uptitration. Primary efficacy measurement was a change in trough (24+/-3 hours after treatment) sitting diastolic BP from the end of the HCTZ run-in to double-blind week 4. Mean changes in systolic and diastolic BP were significantly greater with candesartan cilexetil than with placebo, -11.3/-9.1 mm Hg versus -4.1/-3.1 mm Hg, p <0.001/p <0.001, respectively. Patients with higher sitting diastolic BP at the end of the HCTZ run-in tended to have greater decreases in BP (p <0.05). Most patients (53%) receiving candesartan cilexetil were responders (diastolic BP <90 mm Hg or > or =10 mm Hg decrease) and 32% were controlled (diastolic BP <90 mm Hg). Tolerability and safety profiles were similar in the candesartan and placebo groups. In conclusion, candesartan cilexetil 8 to 16 mg once daily was an effective and well-tolerated therapy for lowering BP when added to HCTZ 12.5 mg in a diverse population of patients with severe systemic hypertension in the United States.

Radon exhalation rate and uranium estimation in rock samples from Bihar uranium and copper mines using the SSNTD technique

Widespread uranium mineralization is associated with copper, nickel and other sulphides in the Singhbhum shear zone developed at the northern margin of the Singhbhum craton in the state of Bihar of India. The south-eastern part of the shear zone between Surda-Mosabani-Badia is rich in copper mineralization while the central part between Jaduguda-Bhatin-Nimdih and Narwapahar-Garadih-Turamdih is enriched in uranium. In the present study, trace uranium concentration in geological samples from the Mosabani copper mine and the Narwapahar and Jaduguda uranium mine areas have been determined using fission track registration technique. For the measurement of the radon exhalation rate, the 'can technique' using alpha sensitive LR-115 type II plastic track detectors were used. Uranium concentrations were found to vary from 1.5 to 2097.9 ppm whereas the radon exhalation rate varied from 0.2 to 19.2 Bq m-2 h-1. The values of radon exhalation rate from crushed rock and soil samples are found to correspond with the measured values of uranium in the corresponding samples. A positive correlation has been found between radon exhalation rate and uranium concentration in the samples. The linear coefficients are found to be 0.40, 0.98 and 0.95 in the Mosabani, Narwapahar and Jaduguda mine areas respectively. High values of radon exhalation in subsurface mines like Jaduguda (depth approximately 800 m) and Mosabani (depth > 1000 m) seem to emphasize the need for adequate ventilation for the removal of radon and its progenies from the mines.

Natural radioactivity of Indian building materials and by-products

Conventional building materials and by-products from coal power plants which are being used or have the potential for use in buildings in India were analysed for natural radioactivity due to the presence of 226Ra, 232Th and 40K using gamma-ray spectroscopy. The materials examined in this work showed the radioactivity levels below the limit estimated from radium equivalent activity the criterion formula for gamma-activity suggested for acceptable radiation doses attributable to building materials in OECD countries.

High prevalence of sexually transmitted and blood-borne infections amongst the inmates of a district jail in Northern India

Two hundred and forty male and 9 female jail inmates confined for various crimes in a district jail near Delhi were screened for sexually transmitted and blood-borne diseases including HIV, syphilis and hepatitis B and C viral infections, skin diseases etc. The inmates were aged 15-50 years with a mean of 24.8+/-0.11. Their alleged criminal background, period of stay in the jail, drug addiction, education, birth place, marital status, sexual activity, and clinical complaints were recorded by an anonymous questionnaire. Serum samples were tested for antibodies against HIV (1+2), hepatitis C (HCV), Treponema pallidum and for hepatitis B surface antigen (HBsAg). Sputum examination was done for acid-fast bacilli. Out of the 240 men, 115 were married and 125 unmarried. One hundred and eighty-four (76.6%) men gave history of penetrative sex. Of the 184, 53 (28.8%) were homosexuals or bisexuals and 131 (71.2%) had sex with women only. Sixty of the 131 (45.8%) were faithful to their partners while 124 gave a history of having multiple sexual partners and 100 of them (80.6%) had unprotected sex. Eighty-three of these 100 also had had sex with commercial sex workers (CSWs). One hundred and twenty-six were addicted for alcohol, 44 for smack/charas and 8 had a history of intravenous drug abuse. One hundred and seventy-four were not aware of AIDS. On examination 28 of the 240 (11.6%) had active hepatitis with or without a history of jaundice in the last 2 years, 25 (10.4%) active pulmonary tuberculosis (TB) and 11 (4.6%) had syphilitic ulcers on the penis. Four-fifths of the teenagers confined to a particular barrack had moderate to severe scabies. Three males (1.3%) were found to be Western blot confirmed HIV-1 positive while 28 (11.1%) men and 2 (22.2%) women were positive for HBsAg. Twelve (5.0%) men but no women, were found to be positive for anti-HCV antibodies. Out of the 3 HIV-positive persons, one was an intravenous drug user (IVDU), second was a drug addict and frequent CSW visitor while the third was a homosexual. This pilot study gives an indication that sexually transmitted and blood-borne infections are highly prevalent in jail premises and pose a threat of rapid spread of these infections through IVDU and homosexuality.

A proposal for nomenclature of aldehyde dehydrogenases in Saccharomyces cerevisiae and characterization of the stress-inducible ALD2 and ALD3 genes

The complete sequencing of the genome of Saccharomyces cerevisiae indicated that this organism contains five genes encoding aldehyde dehydrogenases. YOR374w and YER073w correspond to the mitochondrial isoforms and we propose as gene names ALD4 and ALD5, respectively. YPL061w has been described as the cytoplasmic constitutive isoform and named ALD6. We characterize here the tandem-repeated ORFs YMR170c and YMR169c as the cytoplasmic stress-inducible isoforms, with gene names ALD2 and ALD3, respectively. The expression of ALD2 and ALD3 is dependent on the general-stress transcription factors Msn2,4 but independent of the HOG MAP kinase pathway. ALD3 is induced by a variety of stresses, including osmotic shock, heat shock, glucose exhaustion, oxidative stress and drugs. ALD2 is only induced by osmotic stress and glucose exhaustion. A double null mutant, ald2 ald3, exhibited unchanged sensitivity to any of the above stresses. The only phenotype detected in this mutant was a reduced growth rate in ethanol medium as compared to the wild type.

Purification and characterization of a major zinc binding protein from renal brush border membrane of rat

In spite of the fact that zinc is an essential trace element, mechanisms that contribute to zinc homeostasis in mammals are poorly understood. An attempt has been made to identify and purify zinc binding components from renal brush border membrane (BBM), which could be involved in the binding of zinc and the subsequent translocation across the BBM. A 40 kDa major zinc binding protein has been identified and purified from renal BBM, which showed a dissociation constant (Kd) of 211 microM and maximal binding (Bmax) of 207 nmol/mg protein. 8 g zinc atoms could interact with 1 mol of protein. Specificity of the protein for zinc was checked by metal displacement and UV-absorption assay. It was found that only Cd2+ could displace the zinc bound to the protein. Other metals tested (Cu2+, Mg2+, Ca2+) did not show any interaction with the protein. These data indicated that purified protein is highly specific and has a high affinity for zinc. The carbohydrate content was found to be 7.85 mg% in the purified protein. Immunofluorescence localization of this protein in kidney sections revealed that this major zinc binding protein is exclusively localized in the proximal convoluted tubules. These results suggested that the 40 kDa major zinc binding transmembrane glycoprotein is highly specific for zinc and has a high affinity for zinc.

Efficacy of curcumin in the management of chronic anterior uveitis

Curcumin, obtained from rhizomes of Curcuma longa, was administered orally to patients suffering from chronic anterior uveitis (CAU) at a dose of 375 mg three times a day for 12 weeks. Of 53 patients enrolled, 32 completed the 12-week study. They were divided into two groups: one group of 18 patients received curcumin alone, whereas the other group of 14 patients, who had a strong PPD reaction, in addition received antitubercular treatment. The patients in both the groups started improving after 2 weeks of treatment. All the patients who received curcumin alone improved, whereas the group receiving antitubercular therapy along with curcumin had a response rate of 86%. Follow up of all the patients for the next 3 years indicated a recurrence rate of 55% in the first group and of 36% in the second group. Four of 18 (22%) patients in the first group and 3 of 14 patients (21%) in the second group lost their vision in the follow up period due to various complications in the eyes, e.g. vitritis, macular oedema, central venous block, cataract formation, glaucomatous optic nerve damage etc. None of the patients reported any side effect of the drug. The efficacy of curcumin and recurrences following treatment are comparable to corticosteroid therapy which is presently the only available standard treatment for this disease. The lack of side effects with curcumin is its greatest advantage compared with corticosteroids. A double blind multi-centric clinical trial with this drug in CAU is highly desirable to further validate the results of the present study.

Role of DNA polymerase beta in the excision step of long patch mammalian base excision repair

The two base excision repair (BER) subpathways in mammalian cells are characterized by the number of nucleotides synthesized into the excision patch. They are the "single-nucleotide" BER pathway and the "long patch" (several nucleotides incorporated) BER pathway. Both of these subpathways involve excision of a damaged base and/or nearby nucleotides and DNA synthesis to fill the excision gap. Whereas DNA polymerase beta (pol beta) is known to participate in the single-nucleotide BER pathway, the identity of polymerases involved in long patch BER has remained unclear. By analyzing products of long patch excision generated during BER of a uracil-containing DNA substrate in mammalian cell extracts we find that long patch excision depends on pol beta. We show that the excision of the characteristic 5'-deoxyribose phosphate containing oligonucleotide (dRP-oligo) is deficient in extracts from pol beta null cells and is rescued by addition of purified pol beta. Also, pol beta-neutralizing antibody inhibits release of the dRP-oligo in wild-type cell extracts, and the addition of pol beta after inhibition with antibody completely restores the excision reaction. The results indicate that pol beta plays an essential role in long patch BER by conducting strand displacement synthesis and controlling the size of the excised flap.

Membrane fluidity affects functions of Cdr1p, a multidrug ABC transporter of Candida albicans

Earlier, we have shown that the overexpression of an ABC transporter, CDR1, is involved in the emergence of multidrug resistance in Candida albicans. In this study, we checked its function in vivo by expressing it in different isogenic Saccharomyces cerevisiae erg mutants, which accumulated various intermediates of the ergosterol biosynthesis and thus altered the membrane fluidity. Functions like the accumulation of rhodamine 123, beta-estradiol, fluconazole and floppase activity associated with Cdr1p were measured to ascertain their responses to an altered membrane phase. The floppase activity appeared to be favoured by an enhanced membrane fluidity, while the effluxing of substrates and Cdr1p's ability to confer multidrug resistance were significantly reduced. We demonstrate that only some of the functions of Cdr1p were affected by an altered lipid environment.

Thyroid hormones modulate zinc transport activity of rat intestinal and renal brush-border membrane

Thyroid hormone status influences the Zn2+ and metallothionein levels in intestine, liver, and kidney. To evaluate the impact of thyroid hormones on Zn2+ metabolism, Zn2+ uptake studies were carried out in intestinal and renal brush-border membrane vesicles (BBMV). Steady-state Zn2+ transport in intestinal and renal cortical BBMV was increased in hyperthyroid (Hyper-T) rats and decreased in the hypothyroid (Hypo-T) rats relative to euthyroid (Eu-T) rats. In both the intestinal and renal BBMV, Hyper-T rats showed a significant increase in maximal velocity compared with Eu-T and Hypo-T rats. Apparent Michaelis constant was unaltered in intestinal and renal BBMV prepared from the three groups. Fluorescence anisotropy of diphenyl hexatriene was decreased significantly in intestinal and renal brush-border membrane (BBM) isolated from Hyper-T rats compared with Hypo-T and Eu-T rats. A significant reduction in the microviscosity and transition temperature for Zn2+ uptake in intestinal and renal BBM from Hyper-T rats is in accordance with the increased fluidity of these BBMs. These findings suggest that the increased rate of Zn2+ transport in response to thyroid hormone status could be associated with either an increase in the number of Zn2+ transporters or an increase in the active transporters due to alteration in the membrane fluidity. Thus the thyroid hormone-mediated change in membrane fluidity might play an important role in modulating Zn2+ transport activity of intestinal and renal BBM.

Evaluation of antiallergic activity (type I hypersensitivity) of Inula racemosa in rats

Alcoholic extract of root of Inula racemosa, was studied for its antiallergic effect in experimental models of type I hypersensitivity, viz. egg albumin induced passive cutaneous anaphylaxis (PCA) and mast cell degranulation in albino rats. The alcoholic extract was prepared by the process of continuous heat extraction. LD50 of this extract was found to be 2100 +/- 60 mg/kg, i.p. Assessment of protection against egg albumin induced passive cutaneous anaphylaxix by different doses of Inula racemosa was done by giving drug intraperitoneally or orally for seven days or once only. Mast cell degranulation studies were done by using compound 48/80 as degranulation agent with same dosage schedule. Inula racemosa (i.p. as well as p.o.) showed significant protection against egg albumin induced PCA. Protection against compound 48/80 induced mast cell degranulation by alcoholic extract of Inula racemosa (single dose) was similar to that of disodium cromoglycate. The seven days drug treatment schedule showed greater protection than disodium cromoglycate intraperitoneally. The results suggest that Inula racemosa possesses potent antiallergic properties in rats.

Study of 222Rn concentrations in some dwellings of Rajasthan

Total potential alpha energy concentrations due to radon progeny were measured in 143 dwellings of Udaipur, Bikaner, and Banswara towns of Rajasthan province of India with LR-115 type II detectors. The geometric mean values of total potential alpha energy concentrations in these three towns were found to be 1.9 x 10(-7) J m(-3), 1.2 x 10(-7) J m(-3) and 1.7 x 10(-7) J m(-3) with a geometric standard deviation of 2.2, 2.2, and 2.5, respectively. The estimated lifetime risk of lung cancer due to indoor radon exposure for a total population of study area was estimated to be 6.7 x 10(-3) or 0.67%. The mean relative loss of life expectancies were 0.20%, 0.12%, and 0.18%, respectively.