CYP11B2 gene haplotypes independently and in concurrence with aldosterone and aldosterone to renin ratio increase the risk of hypertension

OBJECTIVES

Aldosterone synthase produces aldosterone, which regulates electrolytes and thereby blood pressure. Polymorphisms in aldosterone-synthase gene (CYP11B2) may associate with heterogeneous aldosterone production and hypertension. Hence, we investigated -344T/C, Iw/Ic polymorphisms of CYP11B2, plasma renin activity (PRA) and aldosterone concentration (PAC).

DESIGN AND METHODS

Consecutive ethnically-matched 450 hypertensive patients and 360 controls were screened by PCR-RFLP for genotypes and haplotypes; PRA and PAC were measured.

RESULTS

The Iw/Ic polymorphism distribution differed significantly between the two groups (LRT chi(2)=15.8, df=2, P=0.000). The mutant allele-Ic and genotype-Ic/Ic were overrepresented in patients (35% versus 27% and 13% versus 7%). Overrepresentation of T-Ic haplotype in patients was identified as risk haplotype (P=0.000). Patients had significantly higher PAC and aldosterone-to-renin ratio (ARR; P=0.000), which was Ic-allele dependent.

CONCLUSIONS

The haplotype T-Ic associated with hypertension susceptibility. Correlation between Ic-allele and raised ARR likely serve in hypertension management.

Multi-locus interactions of vascular homeostasis genes in essential hypertension: a gender-based study

BACKGROUND

Studies on genes of endothelial and vascular homeostasis are inadequate in females.

METHODS

We investigated the role of 7 variants of ACE, AGT and NOS3 and their correlation with NO(x) levels and ACE activity in hypertension susceptibility in 910 case-controls of both genders.

RESULTS

Prevalence of alleles D of ACE I/D; -6A of AGT -6G/A; -786C, 894T and 4a of NOS3 -786T/C, 894G/T and 4b/4a polymorphisms was observed in patients (P< or =0.05). The 3 genotypes-combinations containing 6+5 wild-type alleles of AGT and NOS3 were significantly less prevalent in patients (P< or =0.0003). The haplotypes 235T/174T/-6A of AGT (P=4E-3) and -786T/894G/4a and -786C/894G/4a of NOS3 (P=2E-3, P=0.011, respectively) were significantly more prevalent in patients. The AGT and NOS3 findings were similar in males. Genotypes-combinations with 6+5 wild-type alleles of AGT correlated with higher NO(x) levels (P=0.03). The NOS3 genotypes-combinations having 6 and 6+5 wild-type alleles correlated with decreased ACE activity (P=0.025, P=0.0015, respectively) and increased NO(x) levels (P=0.001, P=0.0001, respectively) in patients. In gene-gene interactions, ACE D allele associated with < or =4 wild-type alleles containing genotypes-combinations of AGT and NOS3 in patients (P< or =0.04).

CONCLUSION

Within gene and between genes interactions of variants influence ACE activity and NO(x) levels and associate with EH.

Endothelial nitric oxide synthase gene haplotypes and circulating nitric oxide levels significantly associate with risk of essential hypertension

Nitric oxide (NO), a potent vasodilator, plays a pivotal role in blood pressure regulation. Endothelial NO synthase gene (NOS3) polymorphisms influence NO levels. Here, we investigated the role of the -922A/G, -786T/C, 4b/4a, and 894G/T polymorphisms of the NOS3 and NO(x) levels in 800 consecutive unrelated subjects comprising 455 patients of essential hypertension and 345 controls. The polymorphisms were investigated independently and as haplotypes. Plasma NO(x) levels (nitrate and nitrite) were estimated by the Griess method. Genotype frequencies for the -786T/C, 4b/4a, and 894G/T polymorphisms differed significantly (P<0.001) between patients and controls and were associated with an increased risk of hypertension (OR=2.0, OR=3.8, OR=1.6, respectively). The 4-locus haplotypes ATaG (H1), ATaT (H2), and GCaG (H3) were significantly associated with essential hypertension and served as susceptible haplotypes (P<or=0.0001). On the other hand, haplotypes ATbG (H4) and GTbG (H5) were negatively associated with hypertension and served as protective haplotypes (P<0.0001). NO(x) levels were significantly lower in patients than controls (P<0.0001). The individual polymorphisms showed marginal association with NO(x) level; however, the susceptible haplotype H2 associated significantly with lower NO(x) levels in patients (P<0.001) and conversely the haplotype H4 with higher NO(x) levels in controls (P<0.001). In conclusion, the 4b/4a and likely -786T/C polymorphisms were identified as the determinants modifying the risk of hypertension. This study identifies the NOS3 variants and haplotypes as genetic risk factors and as useful markers of increased susceptibility to the risk of essential hypertension.

Targeted intracellular delivery of therapeutics: an overview

During the last decade, intracellular drug delivery has become an emerging area of research in the medical and pharmaceutical field. Many therapeutic agents such as drugs and DNA/oligonucleotides can be delivered not just to the cell but also to a particular compartment of that cell to achieve better activity e.g. proapoptotic drugs to the mitochondria, antibiotics and enzymes to the lysosomes and various anticancer drugs and gene to the nucleus. The lipidic nature of biological membrans is the major obstacle to the intracellular delivery of macromolecular and ionic drugs. Additionally, after endocytosis, the lysosome, the major degradation compartment, needs to be avoided for better activity. To avoid these problems, various carriers have been investigated for efficient intracellular delivery, either by direct entry to cytoplasm or by escaping the endosomal compartment. These include cell penetrating peptides, and carrier systems such as liposomes, cationic lipids and polymers, polymeric nanoparticles, etc. Various properties of these carriers, including size, surface charge, composition and the presence of cell specific ligands, alter their efficacy and specificity towards particular cells. This review summarizes various aspects of targeted intracellular delivery of therapeutics including pathways, mechanisms and approaches. Various carrier constructs having potential for targeted intracellular delivery are also been discussed.

Efficient, high-brightness wavelength-beam-combined commercial off-the-shelf diode stacks achieved by use of a wavelength-chirped volume Bragg grating

We report a method of scaling the spatial brightness from commercial off-the-shelf diode laser stacks through wavelength beam combining, by use of a linearly wavelength-chirped volume Bragg grating (VBG). Using a three-bar commercial stack of broad-area lasers and a VBG, we demonstrate 89.5 W cw of beam-combined output with a beam-combining efficiency of 75%. The output beam has a propagation factor M2 approximately 26 on the slow axis and M2 approximately 21 on the fast axis. This corresponds to a brightness of approximately 20 MW/cm2 sr. To our knowledge, this is the highest brightness broad-area diode laser system. We achieve 81% coupling efficiency into a 100 microm, 0.22 N.A. fiber.

Near-diffraction-limited diode laser arrays by wavelength beam combining

We demonstrate 35 W output peak power with M2 approximately 1.35 in both dimensions from a 100 element, 100 microm pitch slab-coupled optical waveguide laser diode array using wavelength beam combining.

Wavelength beam combining of ytterbium fiber lasers

Wavelength beam combining of five ytterbium fiber lasers is demonstrated in a master-oscillator power-amplifier configuration at combined powers up to 6 W. The combined beam profile has an M2 value of 1.14, which is equal to that of an individual fiber. Beam steering in one dimension over 140 resolvable spots is also demonstrated.

Barium carbonate poisoning mimicking Guillain-Barre syndrome

Areflexic quadriplegia due to barium carbonate (rat poison) poisoning is described in two young patients. These cases very closely resembled Guillain-Barre syndrome. The various effects of barium carbonate along with the pathogenesis of hypokalaemic paralysis are highlighted.

High-power 390-nm laser source based on efficient frequency doubling of a tapered diode laser in an external resonant cavity

We frequency doubled the single-frequency beam from an external-cavity tapered laser diode operating at 780 nm in a resonant cavity containing a beta -barium borate crystal to generate an output at 390 nm with high efficiency. Output powers as great as 233 mW were obtained, corresponding to an efficiency of 65%/W . The resonant-cavity design was a low-loss three-mirror configuration that provided compensation for astigmatism and coma. The laser diode frequency was locked to the doubling-cavity resonance by use of the Hänsch-Couillaud discrimination technique.

Amphotericin B lipid complex in the management of antimony unresponsive Indian visceral leishmaniasis

Fifty-eight Indian patients with visceral leishmaniasis who did not respond or relapsed after 30 days of consecutive sodium stibogluconate therapy were randomised to treatment with amphotericin B lipid complex (ABLC) using a total dose of 7.5 or 10 mg/kg. Treatment induced a prompt clinical response in all patients with resolution of fever and regression in spleen size. Fever and chills developed during ABLC infusion, but it diminished with successive infusions. Fourteen days after treatment, 26 of 28 (93%) patients in the 7.5 mg/kg group and all 30 (100%) in the 10 mg/kg group had splenic aspirate parasite density scores of 0 and were considered apparent clinical and parasitologic responders. Four and three patients in the 7.5 and 10 mg/kg groups respectively relapsed during six months of followup; thus, overall 22 of 28 (79%) patients treated with 7.5 mg/kg and 27 of 30 (90%) treated with 10 mg/kg were definitive cures. All initial non-responders and relapses were retreated successfully with higher dose of ABLC. These results confirm the efficacy of short-course ABLC therapy for antimony-unresponsive Indian patients with visceral leishmaniasis. Since treatment with a total dose of 7.5 mg/kg did not appear to increase efficacy (79% vs. 84% induced by 5 mg/kg in a prior study), initial treatment with a total dose of 5 mg/kg followed by retreatment of any non-responders represents a potentially less costly approach in patients who fail antimony therapy. Though high cure rates are achieved with > or = 10 mg/kg total dose of ABLC, treatment using lower doses with retreatment of non-responders or relapses with higher dose can result in considerable savings.

Trial of oral miltefosine for visceral leishmaniasis

BACKGROUND

There is no effective oral treatment for visceral leishmaniasis (kala-azar), a disseminated intracellular protozoal infection that occurs worldwide. Miltefosine, an alkyl phospholipid developed as an oral antineoplastic agent, is active against visceral infection in animal models. We tested safety, tolerance, and efficacy of miltefosine in kala-azar.

METHODS

Oral doses of miltefosine were given to six groups of five Indian men for 28 days: 50 mg every second day (group 1), 100 mg every second day (group 2), 100 mg/day (group 3), 150 mg/day (group 4), 200 mg/day (group 5), and 250 mg/day (group 6). Assessment for apparent cure--taken as an afebrile state with decreased spleen size and a splenic-aspirate parasite-density score of 0--was done on days 14 and 28. Definitive cure at 8 months required a parasite-free bone-marrow aspirate and no clinical evidence of relapse.

FINDINGS

21 of 30 patients were apparently cured on day 14. Transient episodes of vomiting and diarrhoea, were common during weeks 1-2 and were seen in 22 patients. Four other patients in groups 5 and 6 had miltefosine withdrawn after 7-10 days because of vomiting. One patient in group 6 developed renal insufficiency and severe diarrhoea and died on day 21. On day 28, all 29 remaining patients were apparently cured. By 8 months, seven of ten patients in groups 1 and 2 had relapsed; however, 18 of 19 patients treated daily (groups 3-6) appeared to be cured. Among the 21 definitive cures were the four patients treated for 10 days or less and 12 for whom previous therapy with pentavalent antimony had failed.

INTERPRETATION

Treatment with miltefosine at 100-150 mg/day for 4 weeks has promise as an effective oral treatment of visceral leishmaniasis including antimony-resistant infection.

Treatment of antimony-unresponsive Indian visceral leishmaniasis with ultra-short courses of amphotericin-B-lipid complex

High cost is the principal drawback of treating visceral leishmaniasis (VL; kala-azar) with any of the new lipid formulations of amphotericin B. The aim of the present study was to see if the costs of treatment with such drugs could be reduced by using ultra-short courses. Amphotericin-B-lipid complex (ABLC) was given to 77 Indian patients with antimony-unresponsive VL, either as a single infusion of 5 mg/kg (Group A) or two infusions, each of 5 mg/kg, given 5 days apart (Group B) or on consecutive days (Group C). Other than the anticipated higher fever and chills, treatment was well-tolerated. On day 19 after first infusion, 72 patients were considered apparent cures: 24 (89%) of the 27 in Group A; all 24 (100%) in Group B; and 24 (92%) of the 26 patients in Group C. Six months after treatment, 19 (70%) of 27 in Group A, 19 (79%) of 24 in Group B, and 21 (81%) of 26 in Group C were healthy, relapse-free and considered definitive cures. These cure rates were not statistically different. All 18 treatment failures (five initial non-responders and 13 relapses) were cured after treatment with a 5-day course of ABLC at a higher dose (10-15 mg/kg.day). In a related analysis of hospital plus drug costs for treating antimony-unresponsive VL, short-course ABLC (1-5 days) was compared with conventional amphotericin B (0.75-1.0 mg/kg on alternate days over 30-34 days). This analysis, which included the cost of re-treatment, identified one short-course ABLC regimen with an overall estimated expense which was only modestly higher than that of amphotericin B. Together, the present results provide further support for the use of ABLC in the management of VL patients who fail antimony therapy.

MRI of extracranial masses in children: the usefulness of gadolinium-chelate enhancement

OBJECTIVE

This study evaluated the usefulness of gadolinium (Gd) chelates in magnetic resonance imaging (MRI) of extracranial pediatric mass lesions.

MATERIALS AND METHODS

Seventy-five MRI studies were obtained on 60 children (mean age 5.06 years) with pathologically proven mass lesions. Post-contrast T1-weighted (T1W) images were compared with pre-contrast T1-weighted, T2-weighted (T2W) and both T1W and T2W images. They were evaluated for their ability to demonstrate lesion margins and extent, to add additional information, and to increase confidence in or change a diagnosis. In all patients post-contrast images were also evaluated for degree and pattern of enhancement.

RESULTS

Malignant lesions enhanced much more intensely than benign lesions (P<0.0005). Lack of enhancement was seen only in benign lesions. A heterogeneous pattern of enhancement was more frequently seen in malignancy (P<0.05). Additional information was provided on Gd-enhanced T1W images in 36% of cases compared to unenhanced T1 and T2W images. Diagnostic confidence was improved in 29%. The Gd-enhanced images changed the diagnosis correctly in 5% and incorrectly in 1%.

CONCLUSION

Post-contrast images clarified specific issues, better defined lesion extent and margins in a majority of cases, and gave additional useful information in selected cases.

Genetics of naphthalene and phenanthrene degradation by Comamonas testosteroni

Naphthalene and phenanthrene have long been used as model compounds to investigate the ability of bacteria to degrade polycyclic aromatic hydrocarbons. The catabolic pathways have been determined, several of the enzymes have been purified to homogeneity, and genes have been cloned and sequenced. However, the majority of this work has been performed with fast growing Pseudomonas strains related to the archetypal naphthalene-degrading P. putida strains G7 and NCIB 9816-4. Recently Comamonas testosteroni strains able to degrade naphthalene and phenanthrene have been isolated and shown to possess genes for polycyclic aromatic hydrocarbon degradation that are different from the canonical genes found in Pseudomonas species. For instance, C. testosteroni GZ39 has genes for naphthalene and phenanthrene degradation which are not only different from those found in Pseudomonas species but are also arranged in a different configuration. C. testosteroni GZ42, on the other hand, has genes for naphthalene and phenanthrene degradation which are arranged almost the same as those found in Pseudomonas species but show significant divergence in their sequences.

Cloning, sequencing and analysis of the ggh-A gene encoding a 1,4-beta-D-glucan glucohydrolase from Microbispora bispora

The ggh-A gene, encoding a 1,4-beta-D-glucan glucohydrolase/beta-glucosidase, of Microbispora bispora (Mb) was subcloned and expressed from a 4.0-kb XhoI DNA fragment. The nucleotide sequence of this fragment was determined. Analysis of the sequence revealed one open reading frame (ORF) which encodes a 986-amino-acid (aa) protein with a calculated molecular weight of 107,510. The ggh-A ORF has features typical of an actinomycete gene including high GC content (70.5%) and corresponding biased codon usage. Comparison of the aa sequence of the Mb 1,4-beta-D-glucan glucohydrolase (Mbggh-A) with other glycosidases reveals high overall homology to several beta-glucosidases and a 1,4-beta-D-glucan glucohydrolase belonging to the glycosyl hydrolase family 3. The aa sequence alignments of Mbggh-A and beta-glucosidases show that the active site region potentially involves two Asp residues. The aa sequence homology studies revealed a potential two-domain structure for Mbggh-A and other beta-glucosidases. Furthermore, Mbggh-A has localized homology to a cellulose-binding domain present in some xylanases. This report is significant, as, to date, 1,4-beta-D-glucan glucohydrolases have rarely been reported, though they are assumed to have a critical role in cellulolysis.

Molecular cloning of novel genes for polycyclic aromatic hydrocarbon degradation from Comamonas testosteroni GZ39

Three strains of Comamonas testosteroni were isolated from river sediment for the ability to degrade phenanthrene; two of the strains also grew on naphthalene, and one strain also grew on anthracene. The homology of the genes for polycyclic aromatic hydrocarbon degradation in these strains to the classical genes (nah) for naphthalene degradation from Pseudomonas putida NCIB 9816-4 was determined. The three C. testosteroni strains showed no homology to the nah gene probe even under low-stringency conditions. The genes for naphthalene and phenanthrene degradation were cloned from one of the three C. testosteroni strains. Two cosmid clones expressing polycyclic aromatic hydrocarbon dioxygenase activity were identified from a library prepared with genomic DNA from C. testosteroni GZ39. The genes coding for the first two enzymes in the catabolic pathway, phenanthrene dioxygenase and cis-phenanthrene dihydrodiol dehydrogenase, were localized to a 5.4-kb NcoI-PstI fragment by subcloning and gene expression experiments. Further subcloning and analysis revealed a novel organization of the genes, with the gene for cis-phenanthrene dihydrodiol dehydrogenase located between the genes for the individual phenanthrene dioxygenase components. A Southern blot with the cloned genes from C. testosteroni GZ39 confirmed that these genes are distinct from those found in P. putida NCIB 9816-4. Southern blots also demonstrated that C. testosteroni GZ38A possesses genes for phenanthrene degradation that are similar to those cloned from C. testosteroni GZ39. However, C. testosteroni GZ42 possesses genes for phenanthrene degradation that are not homologous to those cloned from C. testosteroni GZ39. This suggests that there are at least two different sets of genes for the degradation of phenanthrene among the three C. testosteroni strains.

Cloning, characterization, and nucleotide sequence of a gene encoding Microbispora bispora BglB, a thermostable beta-glucosidase expressed in Escherichia coli

Genomic DNA fragments encoding beta-glucosidase activities of the thermophilic actinomycete Microbispora bispora were cloned into Escherichia coli. Transformants expressing beta-glucosidase activity were selected by their ability to hydrolyze the fluorogenic substrate 4-methylumbelliferyl-beta-D-glucoside. Two genes encoding beta-glucosidase activity were isolated and distinguished by restriction analysis, Southern hybridization, and the substrate specificities of the encoded enzymes. One gene, bglB, encoded a beta-glucosidase that was expressed intracellularly in E. coli. It exhibited a molecular mass of approximately 52,000 Da by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE) and 51,280 Da by nondenaturing gradient PAGE, a pI of 4.6, and temperature and pH optima of 60 degrees C and 6.2, respectively. Cloned BglB showed greater activity against cellobiose than against aryl-beta-D-glucosides and was thermostable, retaining about 70% of its activity after 48 h at 60 degrees C. BglB activity is activated two- to threefold in the presence of 2 to 5% (0.1 to 0.3 M) glucose. The DNA sequence of the 2.2-kb insert carrying bglB has been determined. An open reading frame which codes for a protein of 473 amino acids with a predicted molecular mass of 52,227 Da showed significant homology (40 to 47% identity) with beta-glucosidases from glycosal hydrolase family 1.

Ultrasonic diagnosis of cirrhosis: reference to quantitative measurements of hepatic dimensions

Hepatic echo patterns and "right lobe to left lobe longitudinal diameter ratio" were compared in age- and sex-matched 100 normal subjects and 76 patients with diffuse liver diseases (38 cirrhotics and 38 noncirrhotics) in a prospective sonographic study. Various echo patterns, assigned to cirrhotic livers (bright liver, micronodulation, beam attenuation), could not differentiate cirrhosis from other diffuse liver diseases. In cirrhotic livers, the right lobe manifested a significant shrinkage, while the left lobe exhibited almost no alteration. Considering the right to left lobe ratio of 1.30 as a discriminatory value, the cirrhosis could be diagnosed with a sensitivity of 74%, a specificity of 100%, and an accuracy of 93%; the sensitivity rates were seen to be higher in postnecrotic cirrhosis than in alcoholic cirrhosis.

Effects of a meal on normal and hypertensive portal venous system: a quantitative ultrasonographic assessment

A prospective sonographic study was undertaken in age- and sex-matched normal subjects and patients with portal hypertension to evaluate the effects of a meal on the portal venous system. Postprandial increase in portal vessel diameters was proved to be statistically significant in normal individuals, with mean variations of 27.9% (16-60%), 46.5% (25-83%), and 45.2% (20-75%), respectively, for portal, splenic, and superior mesenteric veins. In contrast, this effect was insignificant in the hypertensive portal venous system. A diminished meal-related caliber variation in portal, splenic, and mesenteric veins less than 16%, 25%, and 20%, respectively, could be diagnostic of portal hypertension.

Upper gastrointestinal haemorrhage in portal hypertension. Is an emergency endoscopy necessarily required?

Early fibre-optic oesophago-gastroduodenoscopy was performed in 23 portal hypertensive patients with acute upper gastrointestinal haemorrhage to evaluate the source of bleeding. Oesophageal varices grade II or more were documented in all patients. None of the patients showed a source of bleeding other than the ruptured oesophageal varices, probably because, unlike western countries, the alcoholic cirrhosis as a source of portal hypertension is rather uncommon in India. Hence, we could presume that most of the emergency endoscopies are unnecessary in bleeding patients with portal hypertension.

Can sonography replace splenoportovenography in evaluation of patients with portal hypertension?

Real-time sonography and splenoportovenography were compared in 17 patients with portal hypertension for their relative efficacy and limitations with respect to diameters of portal vessels, visualization of collaterals and demonstration of portal vein occlusion. Sonography was able to diagnose portal vein thrombosis and to differentiate an occluded portal vessel from a patent portal vessel non-visualized due to hepatofugal blood flow in the presence of intrahepatic obstruction. However, sonography had limitations in demonstrating venous structures in the presence of excessive bowel gas or fat, and did not provide the flow patterns and the complete picture of the portal vasculature in a single setting. We conclude that the two procedures are complementary to each other, and if combined in patients with portal hypertension, the portal venous system can be evaluated more thoroughly for surgical treatment.

Differential diagnosis of ascitic fluid: evaluation and comparison of various biochemical criteria with a special reference to serum ascites albumin concentration gradient and its relation to portal pressure

Among various biochemical indices measured in 93 patients with ascites, ascitic LDH estimation was proved to be indiscreminatory, while ascites/serum LDH ratio has shown a diagnostic accuracy of 85 per cent. Ascitic total protein levels and ascites/serum total protein ratio (accuracy rates of 72 and 77% respectively) were limited, especially in differentiating the ascites due to heart failure. Serum ascites albumin gradient, showed a strong correlation to portal pressure (r, + 0.83 + 0.88), and was found to be the best diagnostic index (with an overall accuracy of 97 per cent) in distinguishing the 'transudative' from 'exudative' ascites. However, no index could discreminate the 'mixed' cases and provide the etiological diagnosis of the ascites.