Susceptibility to Buruli ulcer is associated with the SLC11A1 (NRAMP1) D543N polymorphism.

Similar to other mycobacterial diseases, susceptibility to Buruli ulcer (Mycobacterium ulcerans infection) may be determined by host genetic factors. We investigated the role of SLC11A1 (NRAMP1) in Buruli ulcer because of its associations with both tuberculosis and leprosy. We enrolled 182 Buruli ulcer patients (102 with positive laboratory confirmation) and 191 healthy neighbourhood-matched controls in Ghana, and studied three polymorphisms in the SLC11A1 gene: 3' UTR TGTG ins/del, D543N G/A, and INT4 G/C. Finger prick blood samples from study subjects were dried on filter papers (FTA) and processed. D543N was significantly associated with Buruli ulcer: the odds ratio (adjusted for gender, age, and region of the participant) of the GA genotype versus the GG genotype was 2.89 (95% confidence intervals (CI): 1.41-5.91). We conclude that a genetic polymorphism in the SLC11A1 gene plays a role in susceptibility to develop Buruli ulcer, with an estimated 13% population attributable risk.

Quantitative estimation of the degree of derivatization: an alternative methodology using 1-D and 2-D NMR experiments.

The precise estimation of the degree of derivatization of functional groups in polymers is important for determining their macroscopic properties. In this work, the quantitative estimation of the extent of esterification of novolac copolymers with di-tert-butyl dicarbonate was studied. Although the extent of esterification has been calculated previously by quantifying the signals from FT-IR and UV-Vis spectroscopy, these were restricted to monitoring the progress of the derivatization process. The 13C NMR signal intensities from the inverse-gated 1H-decoupled NMR spectrum have been used recently for the quantitative estimation of the degree of esterification of polymers. An alternative methodology has been suggested by us based on the fully relaxed 1H chemical shift intensities. However, since the proton signals of novolac resins are generally broad and overlapping, the proton decoupled 13C NMR spectrum was used to identify the 1H NMR signals using the 2-D HSQC technique. A TOCSY experiment was also performed to confirm further the 1H NMR signal assignments and, finally, the deconvoluted 1H NMR spectrum was used for the calculation of the extent of derivatization.

Evaluation of developing rat testis by phosporus 31P magnetic resonance spectroscopy and DNA flowcytometry.

For the assessment of germ-cell maturation of the seminiferous tubules, DNA flowcytometry is a rapid and sensitive method. Phosporus 31P magnetic resonance spectroscopy (MRS) is a non-invasive alternative that demonstrates the metabolic status of the testis, reflecting the type and relative proportion of germ cells in the testis. This study was designed to evaluate the utility of 31P MRS in reflecting the haploid-cell population of the testis as measured by DNA flowcytometry. A single testicle was evaluated in male Wistar pre-pubertal rats at 30, 40, 50, and 60 days of age. In order to minimize the contamination of signals from the contralateral testis, scrotum, and tail, the technique was modified and the testis was evaluated ex-vivo with an intact blood supply. At 30 days of age the percentage of haploid cells was 43.6 +/- 1.8, and this increased to 72.7 +/- 1.4 at 60 days of age. During this period, the testicular phosphomonoester/adenosine triphosphate (PM/ATP) ratio changed from 1.70 +/- 0.21 to 0.32 +/- 0.08. There was a significant (P < 0.001) linear correlation between the proportion of haploid cells evaluated by DNA flowcytometry and the PM/ATP ratio evaluated by 31P MRS. 31P MRS is thus a reliable, noninvasive technique for accurately assessing the status of the seminiferous epithelium.

Epidemiology of selected mycobacteria that infect humans and other animals.

This paper provides a summary of salient clinical and epidemiological features of selected mycobacterial diseases that are common to humans and other animals. Clinical and diagnostic issues are discussed and related to estimates of the incidence and prevalence of these diseases among humans. Source of infection, route of transmission and control measures are also presented. The mycobacteria discussed in this paper are Mycobacterium bovis, M. ulcerans, M. leprae and M. avium complex, although this is by no means a complete list of the mycobacteria common to humans and other animals. Certain generalities can be made regarding these species of mycobacteria and their occurrence in humans and other animals; firstly, current understanding of the epidemiology and control of many of the resultant diseases is incomplete; secondly, environmental sources other than animal reservoirs may play a role in transmission (with M. leprae perhaps being the exception); and thirdly, the incidence and prevalence of these diseases in many countries of the world are unclear, principally because of the complexity of diagnosis and lack of reporting systems.

How effective is syndromic management of STDs?: A review of current studies.

BACKGROUND: Studies of the accuracy of syndromic management have demonstrated widely varying results depending upon gender, location of infection, risk group, organisms, among other factors. GOAL: To review current knowledge about syndromic management of sexually transmitted diseases (STDs) and to make recommendations about the strengths and weaknesses of different syndromic management algorithms. STUDY DESIGN: The authors identified articles and abstracts about the syndromic management of STDs. Evaluation of the effectiveness of algorithms for urethral discharge, genital ulcer disease, and vaginal discharge was based primarily on published sensitivity and specificity data. RESULTS: Overall, algorithms for the diagnosis and treatment of urethral discharge and genital ulcer disease in men had high sensitivities or cure rates (urethral discharge, 87-99%; genital ulcer disease, 68-98%). The sensitivities for the algorithms for vaginal discharge ranged from 73% to 93% among women presenting with symptoms of vaginal discharge, and from 29% to 86% among women not presenting with symptoms. Vaginal discharge was not found to be an effective indicator of cervical infection and, therefore, is not an independently effective screening tool to detect women with cervical infection, especially in low-risk or asymptomatic populations. Incorporating risk scores can improve the accuracy of algorithms to detect cervical infection. CONCLUSIONS: Algorithms for urethral discharge and genital ulcer disease can be effective in STDs. The current algorithms for vaginal discharge are not highly effective in detecting gonorrhea and chlamydia in women; risk scores can improve their efficacy, but must be tailored to reflect community risks. Without attention to the qualitative aspects of STD syndromic management, these methods will likely have even less accuracy than the studies reviewed above. There remains an urgent need for the development of an affordable, rapid, and effective diagnostic technique that will improve STD detection in resource-poor settings.

Optimization of tumor radiotherapy. Part VI: Modification of tumor glucose metabolism for increasing the bioavailability of 2-deoxy-D-glucose (2-DG) in a murine tumor model.

AIM: Differential radiomodification induced by 2-deoxy-D-glucose (2-DG) is proving to be a feasible modality for optimizing tumor radiotherapy. Our earlier work on Ehrlich ascites tumor cells has shown that pretreatment with hematoporphyrin derivatives increases the uptake and phosphorylation of 2-DG. Moreover, the alteration induced in bioenergetic profile was more drastic and less reversible. The promising combination of hematoporphyrin derivatives and 2-DG has been further evaluated in the Ehrlich ascites tumor bearing mice for determining the effects on radiotherapeutic response. MATERIALS AND METHODS: Solid tumors (average volume = 0.9 +/- 0.1 cm3) implanted in Swiss-albino strain "A" mice were focally irradiated (10 Gy) using 60Co teletherapy. Drugs were administered intravenously. Tumor bioenergetics was assessed by 31P MR spectroscopy. RESULTS: The uptake and phosphorylation of 2-DG was observed to be increased following pretreatment with hematoporphyrin derivatives. Upon hematoporphyrin derivatives + 2-DG treatment followed by irradiation, the intracellular pH reduced and a remarkable increase in glycerophosphorylcholine and inorganic phosphate levels was observed. CONCLUSION: The present study demonstrates the potential of hematoporphyrin derivative pretreatment in increasing the bioavailability of 2-DG in a mice Ehrlich ascites tumor model. The finding may have interesting clinical implications in the form of increased manifestation of the radiation-induced damage in the case of use of these drugs as a potential adjuvant in radiotherapy of tumors.

Metabolite mapping of human filarial parasite, Brugia malayi with nuclear magnetic resonance.

Metabolite mapping of human filarial parasite, Brugia malayi was carried out in vitro as well as in situ in host Mastomys coucha by 31P nuclear magnetic resonance (NMR) spectroscopy. Detection of parasites by visualizing contrast spots due to pathologic changes was observed by 1H magnetic resonance imaging (MRI). Major metabolites of adult B. malayi observed by 31P-NMR spectroscopy were of sugar phosphates (SP), phosphomonoesters (PME), glycerophosphoryl-ethanolamine (GPE), -choline (GPC), phosphoenolpyruvate (PEP), inorganic phosphate (Pi), nucleoside diphosphosugar and nucleotides-mono, -di and -tri phosphates. PEP and GPC were present in high concentration; PEP being the major energy reservoir and GPC the major phospholipid in this species of filaria. The 31P NMR spectra of testis of mastomys, showed seven major peaks of SP, PME, phosphocreatine (PCr), phosphodiesters (PDE), Pi, and nucleotides di- and tri-phosphates. The 31P-NMR spectra of testis of B. malayi infected animal also consisted of seven major peaks with significant decrease in the SP and PME peak showing changes in the carbohydrate and lipid metabolism of filaria infected testis. Thus, in vivo 31P MRS provided a non-invasive assessment of tissue bioenergetics and phospholipid metabolism.

Inflammatory granulomas: evaluation with proton MRS.

Intracranial inflammatory lesions consisting mainly of tuberculomas (n = 28), neurocysticercosis (NCC) (n = 10), and non-specific inflammatory granulomas (IG) (n = 22) were evaluated with proton MRS. Water-suppressed proton spectra were acquired from 60 patients using the STEAM sequence with an echo time of 135 ms and metabolite ratios determined from the spectra. Student's paired t-test and chi2-test were used to analyse the data. Statistically significant differences were observed for the following ratios between the three patient categories: NAA/ Cr (p < 0.0001), NAA/Cho (p = 0.001) and Cr/Cho (p = 0.02) for the non-specific IG and NCC, NAA/Cho (p = 0.03) for non-specific IG and tuberculoma, and NAA/Cr (p < 0.0001) for NCC and tuberculoma. While lipids were seen in 86% of the tuberculomas, they were observed in only 20% of the NCCs (chi2 = 6.81, p = 0.009), and 21% of the non-specific IGs (chi2 = 10.75, p = 0.0001). While the presence of lipid can be used for differentiating tuberculomas from both non-specific IG and NCC, the extremely low levels of metabolites together with a poor signal/noise ratio could itself act as a marker for NCC.

Evaluation of the pituitary gland in idiopathic hypogonadotropic hypogonadism.

PURPOSE: Evaluation of the pituitary gland has been carried out in idiopathic hypogonadotropic hypogonadism (IHH) to test the potential of MR imaging in differentiating IHH patients from normals. MATERIAL AND METHODS: Thirty-seven patients (aged 18-30 years), and 20 volunteers (aged 20-30 years) were studied by T1-weighted MR imaging. Length (LA and LP), height (H), width (W), area (AA and AP), and volume (V1A, V1B V2A, V2P) of the pituitary gland were determined. (Subscripts P and A refer to measurements made with and without the posterior lobe, respectively.) V1 and V2 were estimated using two different methods. RESULTS: In the control group, LB W and V2A exhibited significant differences between female and male volunteers. While W was the only parameter that did not show significant difference between normals and patients (in both men and women), all other parameters except LB H and AP showed statistically significant differences between normals and IHH patients in both males and females. While LP was significantly different between normals and patients (men), H and AP were significantly different between normals and patients only in the female group. CONCLUSION: Correlation analysis between various parameters has shown that LA can be used for evaluating the pituitary in both the male and female IHH patients.

Diltiazem enhances tumor blood flow: MRI study in a murine tumor.

PURPOSE: Diltiazem, a calcium-channel blocker, is known to differentially influence the radiation responses of normal and murine tumor tissues. To elucidate the underlying mechanisms, the effects of diltiazem on the radiation response of Ehrlich ascites tumor (EAT) in mice have been investigated, and the hemodynamic changes induced by diltiazem in tumor and normal muscle have been studied using magnetic resonance imaging (MRI) techniques. METHODS AND MATERIALS: Ehrlich ascites tumors were grown subcutaneously in Swiss albino strain A mice. Dynamic gadodiamide and blood oxygen level dependent (BOLD) contrast enhanced 1H MR imaging studies of EAT and normal muscle were performed after administration of diltiazem in mice using a 4.7 Tesla MR scanner. Tumor radiotherapy experiments (total dose = 10 Gy, 0.4-0.5 Gy/min, single fraction) were carried out with 30 min preadministration of diltiazem (27.5 or 55 mg/kg i.p.) to EAT-bearing mice using a teletherapy machine. RESULTS: The diltiazem+ radiation treated group showed significant tumor regression (in approximately/= 65% of the animals) and enhanced animal survival. MR-gadodiamide contrast kinetics revealed a higher magnitude of signal enhancement in diltiazem treated groups as compared to the controls. The observed changes in the magnitude of kinetic parameters were the same for both tumor and normal muscle. BOLD-MR images at 30 min after diltiazem administration showed a 25% and 8% (average) intensity enhancement from their basal values in tumor and normal muscle regions, respectively. The control group showed no significant changes. CONCLUSION: The present studies demonstrate the radiosensitization potential of diltiazem in the mice EAT model. The enhanced radiation response observed with diltiazem correlates with the diltiazem-induced increase in tumor blood flow (TBF) and tumor oxygenation. The present results also demonstrate the applications of BOLD-MR measurements in investigating the alterations in tumor oxygenation status.

Reversal of abnormalities of myelination by thyroxine therapy in congenital hypothyroidism: localized in vivo proton magnetic resonance spectroscopy (MRS) study.

Deficiency of thyroid hormone during central nervous system ontogeny results in a variety of clinical, anatomical and biochemical defects. Delay in thyroxine therapy in newborns with congenital hypothyroidism leads to irreversible brain damage. We have used localized in vivo proton magnetic resonance spectroscopy (MRS) to assess biochemical changes in different regions of brain in three patients with congenital hypothyroidism before and after thyroxine therapy. An abnormal lipid peak which disappeared with thyroxine therapy was observed in cerebellum and frontal lobe in one patient. Statistically significant reduction of NAA/(Cr+PCr) [P<0.009] and elevation of Cho/(Cr+PCr) [P<0.008] ratios in comparison to controls were documented in all three patients which tended to normalise with thyroxine therapy. A variety of biochemical abnormalities relatable to myelin maturation were documented and these were found to be reversible on thyroxine therapy. Reversibility was documented even though thyroxine therapy was initiated at ages beyond which abnormalities in myelinogenesis are considered irreversible. Also, proton MRS revealed biochemical heterogeneity between patients with congenital hypothyroidism.

RNA unwinding in U4/U6 snRNPs requires ATP hydrolysis and the DEIH-box splicing factor Brr2.

BACKGROUND: The dynamic rearrangements of RNA structure which occur during pre-mRNA splicing are thought to be mediated by members of the DExD/H-box family of RNA-dependent ATPases. Although three DExD/H-box splicing factors have recently been shown to unwind synthetic RNA duplexes in purified systems, in no case has the natural biological substrate been identified. A duplex RNA target of particular interest is the extensive base-pairing interaction between U4 and U6 small nuclear RNAs. Because these helices must be disrupted to activate the spliceosome for catalysis, this rearrangement is believed to be tightly regulated in vivo. RESULTS: We have immunopurified Brr2, a DEIH-box ATPase, in a native complex containing U1, U2, U5 and duplex U4/U6 small nuclear ribonucleoprotein particles (snRNPs). Addition of hydrolyzable ATP to this complex results in the disruption of U4/U6 base-pairing, and the release of free U4 and U6 snRNPs. A mutation in the helicase-like domain of Brr2 (brr2-1) prevents these RNA rearrangements. Notably, U4/U6 dissociation and release occur in the absence of exogenously added pre-mRNA. CONCLUSIONS: Disruption of U4/U6 base-pairing in native snRNPs requires ATP hydrolysis and Brr2. This is the first assignment of a DExD/H-box splicing factor to a specific biological unwinding event. The unwinding function of Brr2 can be antagonized by the annealing activity of Prp24. We propose the existence of a dynamic cycle, uncoupled from splicing, that interconverts free and base-paired U4/U6 snRNPs.

Changes in magnetic resonance imaging and sex behavior after 6-OHDA injection in the medial preoptic area.

Magnetic resonance imaging (MRI) of the brains of male rats was done before and after destroying the catecholamine (CA) fibers by local application of 6-hydroxydopamine (6-OHDA) in the medial preoptic area (mPOA). The male sexual behavior was also assessed before and after injection of this toxic drug. The administration of 6-OHDA (8 microg) resulted in highly variable lesions, as shown by MRI and confirmed by histological examination. A hyperintense area was visible either on one or on both sides, about 1-3 h after the administration of the drug. Postmortem histofluorescence showed destruction of CA fibers in the mPOA on those sides that showed hyperintense areas in the MRI. No CA fiber destruction was seen in those rats that had shown no change in MRI after 6-OHDA injection. There was a transient reduction in sex drive score in all the 6-OHDA-treated rats. The present findings point out a correlation between the MRI changes and CA fiber destruction, whereas the transient reduction in the sexual behavior was not related to these changes. It is suggested that some biochemical events related to 6-OHDA destruction of CA fibers may have been responsible for the hyperintensity seen in the MRI.

A spliceosomal recycling factor that reanneals U4 and U6 small nuclear ribonucleoprotein particles.

The spliceosome removes introns from pre-messenger RNAs by a mechanism that entails extensive remodeling of RNA structure. The most conspicuous rearrangement involves disruption of 24 base pairs between U4 and U6 small nuclear RNAs (snRNAs). Here, the yeast RNA binding protein Prp24 is shown to reanneal these snRNAs. When Prp24 is absent, unpaired U4 and U6 small nuclear ribonucleoprotein particles (snRNPs) accumulate; with time, splicing becomes inhibited. Addition of purified Prp24 protein regenerates duplex U4/U6 snRNPs for new rounds of splicing. The reannealing reaction catalyzed by Prp24 proceeds more efficiently with snRNPs than with deproteinized snRNAs.

Volume localized in vivo proton MR spectroscopy of breast carcinoma: variation of water-fat ratio in patients receiving chemotherapy.

Results are reported on in vivo volume localized proton magnetic resonance spectroscopy (MRS) of patients (n = 44) suffering from carcinoma of the breast, using a bilateral breast surface coil. Localized proton MR spectra of the unaffected contralateral breast of these patients are dominated by resonances arising from fat and are similar to the breast tissue from normal volunteers (controls, n = 13), while in the malignant breast tissues the water resonance dominates. On the other hand, the water suppressed proton MR spectra of malignant breast tissue reveal several metabolites of low concentration including the choline peak around 3.2 ppm and other resonances attributable to purine and pyrimidine nucleotides, in the 8.5 ppm region. Elevated water- fat (W-F) ratios are measured in the malignant tissues, compared with the normal breast tissue of controls and from the contralateral unaffected breast tissue of the patients (n = 11). In the case of patients receiving chemotherapy resulting in the reduction of primary tumor size, the W-F ratio shows a statistically significant (P < 0.01) decrease compared with the pre-therapy value, thus providing a non-invasive indicator of favourable clinical outcome of neoadjuvant chemotherapy for locally advanced breast cancer. The method provides the potential for non-invasively monitoring and assessing the response of breast cancer to neoadjuvant chemotherapy.

Evidence for left-right asymmetries in the proton MRS of brain in normal volunteers.

Although there is ample evidence in the literature for structural, functional and physiological asymmetries in the two hemispheres of human brain, direct evidence of a similar asymmetry in the in vivo distribution of brain metabolites has been lacking. In this study, the existence of chemical asymmetries in six different regions in normal human brain has been probed with single voxel proton spectroscopy using the STEAM technique in 100 normal right-handed male volunteers. Significant interhemispheric differences in the spectra were observed for all the regions studied in all the volunteers, although statistically significant asymmetries existed only for temporal, occipital and parietal regions. In addition to proven structural and functional asymmetries in the human brain, in vivo evidence of chemical asymmetry has been provided using Magnetic Resonance Spectroscopy.

1H magnetic resonance imaging and 31P magnetic resonance spectroscopy in experimental filariasis.

1H Magnetic resonance imaging and 31P magnetic resonance spectroscopy (MRS) have been carried out in experimental rodent filariasis, i.e., Acanthocheilonema viteae infection in the rodent host, Mastomys coucha. The T2-weighted image of the infected host shows fine hyperintense thread like structures of adult filariid nests in the cervical region. 31P MRS of normal and infected hosts, localized over the same region of interest, show seven major peaks corresponding to phosphomonoesters (including glucose-6-phosphate, fructose-6-phosphate, fructose-1-6-diphosphate, phosphorylcholine, and adenine monophosphate or AMP), inorganic phosphate, glycerophosphorylcholine, phosphoenolpyruvate, phosphocreatine and nucleoside di- and tri-phosphates. Concentrations of phosphomonoesters (PMEs) are higher in the normal rodent compared with the infected ones. In vivo 31P MRS provides a non-invasive assessment of tissue bioenergetics and phospholipid metabolism.

Magnetic resonance imaging of NMDA-induced lesion of the medial preoptic area and changes in sleep, temperature and sex behaviour.

Destruction of the medial preoptic area (mPOA) neurons of rat brain, induced by intracerebral injection of N-methyl D-aspartic acid (NMDA), has been studied by employing the non-invasive Magnetic Resonance Imaging (MRI) technique. Changes in the MRI images are compared and correlated with the functional changes after the mPOA lesion. The progress of the lesion at the injected site has been monitored (using MRI) from 15 min to 1 month after the stereotaxic microinfusion of NMDA (5 micrograms in 0.2 microliter). This study shows that the localised hyperintense (bright) area starts appearing at the mPOA from 3 h after NMDA injection, and the brightness increases progressively for about 2 days. The size and brightness of hyperintense area decrease thereafter. It has not been possible to locate the lesion site after 3 days, using MRI, except in one rat where a vacuole-like area was seen at the NMDA injected site on postmortem histological examination. The reduction in sleep after the mPOA lesion does not show any correlation with the changes in MRI, as it persists throughout the 3 weeks of recording. On the other hand, the initial drastic reduction in male sex behaviour and the increase in body temperature correlated to some extent with the increased brightness in MRI at the site of lesion. The size and location of the hyperintense area, observed during the first 2 days, match with the lesioned area which was histologically identified after 1 month of NMDA administration. Control administration of normal saline into the mPOA did not produce any alteration in the brightness of the MRI image and practically no loss of neurons at the injected site. Though some functional changes have correlation with the alteration in MRI, this cannot be used to interpret the changes in all the physiological parameters. This study also demonstrates that the disappearance of the brightness in MRI should not be taken to indicate a positive prognosis. Though the lesion could not be seen in MRI within 2 hours, its detection after 3-4 h (but within 3 days) after NMDA lesion would give very valuable information for long term studies.

Magnetic resonance imaging of temporal changes of neurotoxic lesion in the rat.

Destruction of striatal neurons in the rat brain, induced by intracerebral injection of N-methyl D-aspartic acid (NMDA), has been visualized noninvasively by magnetic resonance imaging (MRI). The changes in images were monitored from 12 h to one month after the stereotaxic microinfusion of NMDA (10 micrograms in 0.4 microliter) into the striatum, using a T2-weighted rapid acquisition by relaxation enhancement (RARE) sequence. A localised hyperintense (bright) area was visible after 12 h at the site of the injection, and it persisted for the next three days. The size of the hyperintense area decreased thereafter and, after one week, the increased brightness was restricted to the lateral ventricle. Post-mortem histological examination, done after one month, showed a dilated lateral ventricle. The size and location of the lesioned area, identified in histological sections, corresponded to the hyperintense area observed during these initial days after NMDA lesion. The present study demonstrates that noninvasive MRI techniques, using a typical RARE sequence, offer a powerful tool for the early detection of neurotoxic lesion of the brain area, although some caution is required in its use for estimating the size of the lesioned area three days after its formation. The present findings indicate that, in long-term studies, alterations of the neighbouring structures, such as enlargement of the ventricular system, may confound the MRI evaluation of neurotoxic lesions in vivo.

Brain metabolite changes in alcoholism: an in vivo proton magnetic resonance spectroscopy (MRS) study.

Image-guided, single voxel, localized proton magnetic resonance (MR) spectroscopy was performed to assess the brain metabolite changes in 10 (n = 10) alcoholic patients in the frontal lobe, cerebellum, and thalamus regions. The spectra obtained were characterized by a reduced N-acetyl-aspartate (NAA) to choline (Cho) (p < .01) and NAA to total creatine (Cr + PCr) (p < .01) ratios relative to age-matched (n = 27) controls. These decreased ratios correspond to depleted concentration of the metabolite levels such as NAA and Cho. Reduction of NAA is consistent with the neuronal loss while reduction in Cho suggests significant changes in the membrane lipids of alcoholics.