Use of an inflatable balloon on a catheter to prevent subdural fluid collections after intraventricular tumor surgery: technical note

Ventricular tumor surgeries pose significant challenges to the neurosurgeon. Apart from the operative challenges and typical complications of surgery, subdural fluid collection is common after these surgeries. Various methods have been used to prevent this complication. The authors' technique of implanting an inflatable balloon attached to a catheter after resection of a huge intraventricular tumor was highly effective in preventing the development of a subdural fluid collection.

Semi-nested polymerase chain reaction for detection of toxigenic Vibrio cholerae from environmental water samples

A rapid and sensitive direct cell semi-nested PCR assay was developed for the detection of viable toxigenic V. cholerae in environmental water samples. The semi-nested PCR assay amplified cholera toxin (ctxA2B) gene present in the toxigenic V. cholerae. The detection sensitivity of direct cell semi-nested PCR was 2 × 10(3) CFU of V. cholerae whereas direct cell single-step PCR could detect 2 × 10(4) CFU of V. cholerae. The performance of the assay was evaluated using environmental water samples after spiking with known number of Vibrio cholerae O1. The spiked water samples were filtered through a 0.22 micrometer membrane and the bacteria retained on filters were enriched in alkaline peptone water and then used directly in the PCR assay. The semi-nested PCR procedure coupled with enrichment could detect less than 1 CFU/ml in ground water and sea water whereas 2 CFU/ml and 20 CFU/ml could be detected in pond water and tap water, respectively. The proposed method is simple, faster than the conventional detection assays and can be used for screening of drinking water or environmental water samples for the presence of toxigenic V. cholerae.

CA repeat and RsaI polymorphisms in ERbeta gene are not associated with infertility in Indian men

Oestrogen Receptor beta (ERbeta) gene plays an important role in the regulation of fertility in both males and females. Polymorphism in CA repeat located in the flanking region of ERbeta has been shown to be associated with several diseases, but its association with male infertility has not been analysed so far. However, RsaI polymorphism (rs1256049) in exon 5 of ERbeta has been shown to be associated with male infertility in Caucasian patients. Hence, we have analysed 695 Indian men, including 443 infertile and 252 fertile men to evaluate the association of CA repeat length and RsaI polymorphisms in male infertility. Our results revealed no significant difference in the distribution of CA repeat length between infertile (mean +/- SD 23.24 +/- 2.06, median 24) and fertile men (mean +/- SD 23.16 +/- 2.27, median 24). The analysis of dosage effect by classifying samples into SS (short/short), SL (short/long) and LL (long/long) groups also did not show any significant difference between infertile and fertile men. Similarly, RsaI polymorphism also did not show any significant difference between infertile and fertile men. Furthermore, the combined analysis of CA repeat and RsaI polymorphisms by haplotyping showed that the distribution of haplotypes was not significantly different between fertile and infertile men. Our results suggest that CA repeat length and RsaI polymorphisms in ERbeta are not associated with infertility in Indian men.

Expression of interferon-gamma- inducible protein-10 and its receptor CXCR3 in chronic pancreatitis

AIM

The role of CXC chemokine, interferon-gamma-inducible protein-10 and its receptor CXCR3 in pathophysiology of chronic pancreatitis (CP) is not very clear. Hence, this study was carried out to analyze the expression of CXCL10 and CXCR3 in CP tissues.

METHODS

Pancreatic tissues from 25 histopathologically graded CP cases (11 alcohol associated CP, 5 confirmed idiopathic and 9 of undefined nature) and 10 normal cases were studied. Tissues were subjected to real-time PCR, immunohistochemistry, and Western blot analysis for CXCL10 and CXCR3 expression.

RESULTS

Real-time (RT)-PCR revealed increased expression of CXCL10 (13-fold) and CXCR3 (7-fold) in CP tissue. The immunohistochemistry and Western blot analysis of the same showed significant increased protein expression and correlated well with the histopathological grades. The CXCL10 was localized mainly in the cytoplasm of pancreatic acinar cells and expression increased from grade I to grade II and declined in grade III while no expression was recorded in normal. The CXCR3 was expressed strongly at the acinar cell membrane in CP as compared to normal. Further, comparative analysis by semiquantitative RT-PCR analysis was performed for other CXC/CC chemokines (CXCL9, CXCL11, CCL3, CCL4, CCL5) and receptor (CCR5) which revealed their upregulation in the diseased state.

CONCLUSION

The existence of CXCL10 and CXCR3 with other CXC/CC chemokine signature in CP is suggestive of their vital role in the progression of chronic inflammation.

Single multiplex polymerase chain reaction for environmental surveillance of toxigenic-pathogenic O1 and non-O1 Vibrio cholerae

A multiplex PCR assay was developed for the detection of toxigenic and pathogenic V. cholerae from direct water sources using specific primers targeting diverse genes, viz. outer membrane protein (ompW), cholera toxin (ctxB), ORF specific for O1 (rfbG), zonula occludens (zot) and toxin co-regulated pilus (tcpB); among these genes, ompW acts as internal control for V. cholerae, the ctx gene as a marker for toxigenicity and tcp for pathogenicity. The sensitivity of multiplex PCR was 5 x 10(4) V. cholerae cells per reaction. The procedure was simplified as direct bacterial cells were used as template and there was no need for DNA extraction. The assay was specific as no amplification occurred with the other bacteria used. Toxigenic V. cholerae were artificially spiked in different water samples, filtered through a 0.45 microm membrane, and the filters containing bacteria were enriched in APW for 6 h. PCR following filtration and enrichment could detect as little as 8 V. cholerae cells per mL in different spiked water samples. Various environmental potable water samples were screened for the presence of V. cholerae using this assay procedure. The proposed method is rapid, sensitive and specific for environmental surveillance for the presence of toxigenic-pathogenic and nonpathogenic V. cholerae.

Amperometric immunosensor for the detection of Vibrio cholerae O1 using disposable screen-printed electrodes

A disposable amperometric immunosensor was studied for the rapid detection of Vibrio cholerae (V. cholerae), the causative agent of cholera, employing an indirect sandwich enzyme linked immunosorbent assay (ELISA) principle. Screen-printed electrodes (SPEs) were fabricated (by using commercial and homemade carbon inks), electrochemically characterized and the assay conditions were optimized for capturing antibodies and antigen. Whole cell lysate (WCL) of V. cholerae was used to raise antibodies in rabbits and mice. The antibodies raised against WCL of V. cholerae were found to be specific, and no cross reactivity was observed with other enteric bacteria. 1-Naphthyl phosphate was used as a substrate with the amperometric detection of its enzymatic hydrolysis product 1-naphthol at a potential of +400 mV vs. Ag/AgCl reference electrode. A comparison between the amperometric detection technique and the standard ELISA was made in terms of the total assay time, the amount of biological materials used and the sensitivity of detection. The minimum detection limit of the amperometric immunosensor for V. cholerae was found to be 10(5) cells/ml in 55 min, while ELISA detected 10(6) cells/ml in 4 h.

Isolation and characterization of heat resistant enterotoxigenic Staphylococcus aureus from a food poisoning outbreak in Indian subcontinent

Outbreaks of staphylococcal food poisoning (SFP) are very common across the world; however, there is hardly any report of SFP from the Indian subcontinent. An outbreak occurred in the state of Madhya Pradesh (India) after the consumption of a snack called "Bhalla" made up of potato balls fried in vegetable oil. More than 100 children and adults who ate the snack suffered from the typical symptoms of SFP and required hospitalization. Food and clinical samples were found to contain a large number of enterotoxigenic Staphylococcus aureus. All enterotoxigenic isolates produced a combination of SEB and SED enterotoxins and were sensitive to oxacillin and vancomycin. Isolates were characterized by molecular biology tools, viz., SDS-PAGE, amplified ribosomal DNA restriction analysis (ARDRA), randomly amplified polymorphic DNA (RAPD) and nucleotide sequencing of seb, sed, and 16S rDNA genes. Results of these studies suggested that the isolates, irrespective of their isolation from food or clinical samples, were clonal in origin. Further, seb gene sequence of isolates showed nucleotide variations at multiple sites when compared with other sequences available in the database. Representative isolates, one each from food and clinical samples, were found to be highly heat resistant (D(60) approximately 15-16 min). Isolates obtained in the current outbreak need to be further studied to find out the impact on food safety guidelines with respect to thermal processing.

Surgical treatment of pulmonary aspergilloma: a series of 72 cases

BACKGROUND

The objective of this study was to evaluate the immediate and long-term result of resectional surgery in pulmonary aspergilloma.

METHODS

Seventy-two patients who underwent pulmonary resectional surgery for symptomatic aspergilloma between 1990 to 2002 were studied. Seventy-nine definitive operations were carried out, including one bilateral lobectomy for recurrent lesions and six thoracoplasties to deal with post-operative complications, besides 21 pneumonectomies and 51 lobectomies. There were 10 bilobectomies as well, included in the lobectomy group.

RESULTS

At a mean follow-up of 3.5 years, there were two post-operative deaths and a few complications occurred in 20 cases translating into a morbidity of 28.57% and a mortality of 2.77 percent. Major complications included were persistent air leak, persistent pleural space, empyema, bronchopleural fistula and massive haemorrhage. All events were seen in cases of complex aspergilloma; cases of simple aspergillomas had an uneventful course.

CONCLUSIONS

Surgery offers definitive and long-term symptom-free survival in cases of pulmonary aspergilloma at a negligible risk; though almost one-third of those undergoing surgery develop some complications, these are largely manageable.

Purification and characterization of an extracellular protease produced by psychrotolerant Clostridium sp. LP3 from lake sediment of Leh, India

An anaerobic, proteolytic bacterium isolated from lake sediments of Leh, India, was characterized with respect to morphology, biochemical characteristics, and 16S rRNA sequence and was identified as Clostridium species, with closest similarity to Clostridium subterminale. Isolate LP3 was psychrophilic, forming maximum cell mass between 10 and 20 °C, and produced extracellular protease. Growth was observed in the pH range of 7.0–8.5, with optimum at pH 7.5. Protease was purified 62.4-fold with a total yield of 17.5%. The effects of temperature, pH, and salt concentration on enzyme activity were studied. Protease was found to be a serine-type metallo-enzyme, active in a broad range of pHs. It was thermolabile and resistant to sodium dodecyl sulfate. Enzyme kinetics showed a tendency to increase Km with an increase in temperature for casein substrate.Key words: Clostridium sp., psychrotolerant, protease, anaerobe.

A to G transitions at 260, 386 and 437 in DAZL gene are not associated with spermatogenic failure in Indian population

The autosomal DAZL (Deleted-in-Azoospermic-Like) gene, mapped to the short arm of the human chromosome 3, is the precursor for the Y-chromosomal DAZ cluster, which encodes for putative RNA-binding proteins. Mutations in the DAZL have been reported to be associated with spermatogenic failure in Taiwanese population but not in Caucasians. As there was no study on Indian populations, we have analysed the entire coding sequences of exons 2 and 3 of DAZL in a total of 1010 men from Indian subcontinent, including 660 infertile men with 598 non-obstructive azoospermia, 62 severe oligozoospermia and 350 normozoospermic fertile control men, to investigate whether mutation(s) in the DAZL is associated with male infertility. Interestingly, none of our samples (1010) showed A386G (T54A) mutation, which was found to be associated with spermatogenic failure in Taiwanese population. In contrast, A260G (T12A) mutation was observed in both infertile and normozoospermic fertile control men, without any significant association with infertile groups (chi2= 0.342; p = 0.556). Similarly, we have found a novel A437G (I71V) mutation, which is also present in both infertile and normozoospermic fertile control men without any significant difference (chi2 = 0.476; p = 0.490). Our study clearly demonstrates the complete absence of the A386G (T54A) mutation in Indian subcontinent and the other two mutations --A260G (T12A) and A437G (I71V)--observed are polymorpic. Therefore, we conclude that these mutations in the DAZL gene are not associated with male infertility in Indian subcontinent.

Novel mitochondrial mutation in the ND4 gene associated with Leigh syndrome

We analyzed the complete mitochondrial genome of a 3-month-old female child with basal ganglionic lesions and other clinical features suggestive of Leigh syndrome, which is caused by variations in mitochondrial and nuclear genes. Our study revealed a novel, homoplasmic T11984C missense mutation in ND4 gene, which replaces a highly conserved amino acid tyrosine with histidine. Computational analysis showed that this mutation alters the secondary structure of ND4 subunit. As the mutation observed in this study was novel and homoplasmic, we speculate that there could be interplay of this mitochondrial mutation along with nuclear gene(s) in the pathogenesis.

Integrated application of some compatible biocontrol agents along with mustard oil seed cake and furadan on Meloidogyne incognita infecting tomato plants

Experiments were carried out to study the effect of two fungal bioagents along with mustard oil cake and furadan against root knot nematode Meloidogyne incognita infecting tomato under greenhouse condition. Bioagents viz., Paecilomyces lilacinus and Trichoderma viride alone or in combination with mustard cake and furadan promoted plant growth, reduced number of galls/plant, egg masses/root system and eggs/egg mass. The fungal bioagents along with mustard cake and nematicide showed least nematodes reproduction factor as compared to untreated infested soil.

Coat protein gene diversity among Chrysanthemum virus B isolates from India

The complete coat protein (CP) sequences from 29 Indian isolates of Chrysanthemum virus B (CVB) were determined and analysed in relation to other previously characterized carlaviruses. The CP genes of the Indian CVB isolates were highly heterogeneous, sharing nucleotide sequence identities of 74-98%. Based on phylogenetic analyses, the isolates formed three groups potentially representing either two or three major CVB strain groupings. Recombination analysis revealed at least one definite recombination event involving the exchange of sequences between members of different groups. To our knowledge this is the first reported evidence of homologous recombination in carlaviruses.

Association of cathepsin B gene polymorphisms with tropical calcific pancreatitis

BACKGROUND AND AIMS

Tropical calcific pancreatitis (TCP) is a type of chronic pancreatitis unique to countries in the tropics. Mutations in pancreatic secretory trypsin inhibitor (SPINK1) rather than cationic trypsinogen (PRSS1) explain the disease in only 50% of TCP patients. As cathepsin B (CTSB) is known to activate cationic trypsinogen, we attempted to understand the role of CTSB mutations in TCP. Evidence of epistatic interaction was investigated with the previously associated N34S SPINK1 allele, a variant considered to be a modifier rather than a true susceptibility allele.

SUBJECTS AND METHODS

We sequenced the coding region of CTSB gene in 51 TCP patients and 25 controls and further genotyped 89 patients and 130 controls from the same cohort for Leu26Val, C595T, T663C, and Ser53Gly polymorphisms. The positive findings observed in the earlier cohort were re-examined in an ethnically matched replication cohort comprising 166 patients and 175 controls. Appropriate statistical analyses were performed and Bonferroni correction for multiple testing was applied.

RESULTS

We found a statistically significant association of the Val26 allele at Leu26Val polymorphism with an odds ratio (OR) of 2.15 (95% confidence interval (CI) 1.60-2.90 (p = 0.009)), after Bonferroni correction (corrected p value = 0.025). This significant association of Leu26Val with TCP was replicated in another cohort (OR 2.10 (95% CI 1.56-2.84); p = 0.013). Val26 allele also showed significantly higher frequency in N34S positive and N34S negative patients than in controls (p = 0.019 and 0.013, respectively). We also found significant differences in the mutant allele frequencies at Ser53Gly and C595T single nucleotide polymorphisms between N34S positive patients and controls (p = 0.008 and 0.001, respectively). Although haplotype analysis did not complement the results of allelic association, it did uncover a unique haplotype protective for TCP (p = 0.0035).

CONCLUSION

Our study suggests for the first time that CTSB polymorphisms are associated with TCP. As PRSS1 mutations are absent in TCP and the N34S SPINK1 mutation is proposed to play a modifier role, these variants may be critical as a trigger for cationic trypsinogen activation.

Development of an immunodetection test for a botulinum-like neurotoxin produced by Clostridium sp. RKD

BACKGROUND & OBJECTIVES

Clostridial neurotoxins are among the most toxic substances known and cause severe illnesses in both humans and animals. A neurotoxigenic Clostridium sp. (strain RKD) isolated from intestine of decaying fish produced a novel, botulinum type B like neurotoxin as suggested by mouse bioassay, protection with anti-botulinum antibodies and PCR. The aim of the present investigation was to develop a laboratory based detection assay as an alternative to the mouse bioassay without compromising sensitivity and specificity.

METHODS

Growth and toxin production were carried out in trypticase peptone yeast-extract glucose (TPYG) broth. Toxicity was estimated in terms of minimum lethal dose (MLD) by mouse bioassay. The toxin was partially purified by acid precipitation. It was used for toxoid preparation by formaldehyde treatment. This purified IgG was used for detection of neurotoxin using indirect ELISA. The culture supernatant was concentrated using a stirred cell with a 50 kDa cut-off membrane at 4 degrees C. Further purification was carried out using Prep cell. Fractions showing toxicity and sufficient purity were pooled, concentrated and analyzed on sodium dodecyl sulphatepolyacrylamide gel electrophoresis (SDS-PAGE).

RESULTS

The toxin was purified with a recovery of 8.56 per cent. Polyclonal antiserum was raised in mice using partially purified toxin with a titre of 1: 80000. A detection assay with sensitivity of approximately 15 and 300 ng/ml for partially purified and crude toxins, respectively were achieved using an indirect ELISA method.

INTERPRETATION & CONCLUSION

The Clostridium sp. RKD produced a potent neurotoxin earlier shown to have novelties. A specific detection assay for the neurotoxin has been developed that may be useful both from food safety and clinical point of view.

Unique origin of Andaman Islanders: insight from autosomal loci

Our mtDNA and Y chromosome studies lead to the conclusion that the Andamanese "Negrito" mtDNA lineages have survived in the Andaman Islands in complete genetic isolation from other South and Southeast Asian populations since the initial settlement of the region by the out-of-Africa migration. In order to obtain a robust reconstruction of the evolutionary history of the Andamanese, we carried out a study on the three aboriginal populations, namely, the Great Andamanese, Onge and Nicobarese, using autosomal microsatellite markers. The range of alleles (7-31.2) observed in the studied population and heterozygosity values (0.392-0.857) indicate that the selected STR markers are highly polymorphic in all the three populations, and genetic variability within the populations is significantly high, with a mean gene diversity of 77%. The Andaman "Negrito" populations do not show particular affinities either with the African populations or with the Indian populations, confirming their unique origin. In contrast, Nicobarese show close affinities with the Southeast Asian populations, suggesting their recent entry in the Islands.