Quantitative structure activity relationship and risk analysis of some heavy metal residues in the milk of cattle and goat

Milk of cattle and goat was collected from various localities of Faisalabad, Pakistan. Heavy metal concentration in milk was determined by atomic absorption spectrophotometer. Milk from both of the species was found richly contaminated with cadmium (Cd), chromium (Cr), nickel (Ni), and lead (Pb). Lead concentration in the milk of goat was significantly higher as compared to cattle milk. Quantitative structure activity relationship (QSAR) models were suggested to predict the residues of unknown heavy metals in the milk of cattle and goat using their known physicochemical properties such as molecular weight (MW), melting point (MP), and boiling point (BP) as well as the milk characteristics such as pH, % fat, and specific gravity (SG) of both of these species. The analysis revealed good correlation coefficients ( R2 = 0.759) and ( R2 = 0.876) for cattle and goat QSAR models, respectively. This analysis indicates the need to construct species specific QSAR models for residue prediction. The coefficients for SG for the studied metals were higher in both cattle and goat milk. This suggests that SG is a better determinant for heavy metal residue prediction in the milk of these animals. Risk analysis was conducted based upon the determined heavy metal residues and their provisional tolerable daily intakes. The daily intake of Cd, Cr, and Pb was found to be 1.6, 27, and 116 times higher, respectively, in cattle milk and 1.8, 29, 262 times higher respectively, in goat milk. This intake of heavy metal contaminated milk might pose health hazards to humans in this locality.

Effect of thioperamide on oxidative stress markers in middle cerebral artery occlusion model of focal cerebral ischemia in rats

In view of the recent evidence for the involvement of histamine in cerebral ischemia, the present study evaluated the effect of thioperamide (THP), a selective histamine H3-receptor antagonist, on middle cerebral artery occlusion (MCAO) induced focal cerebral ischemia in rats. The rats were subjected to 2 h of MCAO followed by 22 h reperfusion after which the grip strength, locomotor activity and spontaneous alternation performance were assessed. Animals were then killed and oxidative stress markers were estimated in the whole brain. An elevation of thiobarbituric acid reactive substance (TBARS) and a reduction in glutathione (GSH) and antioxidant enzymes, such as glutathione-S-transferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR) and superoxide dismutase (SOD), was observed following MCAO, the last two being statistically insignificant. Pretreatment with THP (5.5 mg/kg i.p. and 11 mg/kg i.p.) significantly reversed the MCAO-induced increase in TBARS, but could not reverse the other parameters. Paradoxically, it further reduced the levels of GPx, GR and SOD. No significant changes were observed in the catalase levels and in the grip strength and spontaneous alternation behavior of rats. Locomotor activity was reduced slightly, but reversed on pretreatment with THP. The dual effect of THP on oxidative stress requires further investigation and raises doubts on its possible use in cerebral ischemia.

Crystallization and preliminary X-ray diffraction analysis of L-threonine dehydrogenase (TDH) from the hyperthermophilic archaeon Thermococcus kodakaraensis

The enzyme L-threonine dehydrogenase catalyses the NAD(+)-dependent conversion of L-threonine to 2-amino-3-ketobutyrate, which is the first reaction of a two-step biochemical pathway involved in the metabolism of threonine to glycine. Here, the crystallization and preliminary crystallographic analysis of L-threonine dehydrogenase (Tk-TDH) from the hyperthermophilic organism Thermococcus kodakaraensis KOD1 is reported. This threonine dehydrogenase consists of 350 amino acids, with a molecular weight of 38 kDa, and was prepared using an Escherichia coli expression system. The purified native protein was crystallized using the hanging-drop vapour-diffusion method and crystals grew in the tetragonal space group P4(3)2(1)2, with unit-cell parameters a = b = 124.5, c = 271.1 A. Diffraction data were collected to 2.6 A resolution and preliminary analysis indicates that there are four molecules in the asymmetric unit of the crystal.

First national tuberculin survey in Nepal

SETTING

The size of the tuberculosis (TB) problem in Nepal is unknown, as no national tuberculin or TB prevalence survey has yet been performed.

OBJECTIVE

To assess the prevalence of TB infection and the annual risk of TB infection (ARTI) in primary schoolchildren in the three ecological zones (mountains, hills and terai) and Kathmandu valley.

DESIGN

A representative sample of primary schoolchildren were tuberculin skin tested using the Mantoux method. The data were analysed using cut-off levels to define infection and by the mirror method.

RESULTS

Of 19577 children registered, 17260 (88.2%) were available for analysis. Seventy-eight per cent had a visible bacille Calmette-Guérin scar. The best estimate of the prevalence of TB infection was 7.0% (95%CI 4.2-9.7), with an ARTI of 0.86% (95%CI 0.49-1.23) using the mirror method, with a mode at 16 mm. Although the ARTI was higher in Kathmandu and the mountains compared to the hills and terai, the difference between the areas was not significant.

CONCLUSION

The ARTI in Nepal is lower than previous estimates, indicating a decrease in transmission or overestimation of previous estimates. To obtain information about the trend of the ARTI in Nepal, the survey needs to be repeated in 5 to 7 years.

Estimation of atrazine in the stratum corneum and its toxic effects in skin following topical application to rabbits

ABSTRACT For risk assessment, a workable non-invasive method for the estimation of atrazine in skin was needed. Moreover, the dermato-toxic effects of different concentrations of atrazine have not been studied so far. Fifteen milligrams of 35% solution of atrazine in ethanol was topically applied to each of six different clipped sites on the back of rabbits (n = 6). Each site was tape-stripped with 10 consecutive adhesive tapes at 0.5, 1, 2, 3, 4, and 6 h of topical dosing to remove the stratum corneum (SC). Atrazine in tapes was extracted with methanol and analyzed with HPLC. The amount of atrazine detected in the SC at 6 h (1955.79 +/- 47.22 mug) is equivalent to 13.03% of the total applied dose. In dermal toxicity studies, 500 mul of 35%, 70% atrazine in ethanol and a commercial preparation of atrazine (Balance(R)) was dosed on clipped backs of rabbits (n = 4) for 4 days under occluded vs non-occluded conditions. Ethanol alone served as control. On the 5th day, rabbits were euthanized and skin was scored for erythema and then examined microscopically. Significant differences (p < 0.05) in erythema scores were observed with 70% atrazine and Balance(R) as compared to the control under occluded conditions. Significant differences in epidermal thickness and cell layers were observed with Balance(R) and 74% atrazine as compared to control in both dosing conditions. There were non-significant differences in erythema, epidermal thickness, or cell layers in occluded vs non-occluded applications of atrazine in ethanol, indicating that atrazine is equally toxic regardless of its application procedures. Moreover, under non-occluded application, very slight erythema was observed but microscopically significant epidermal hyperplasia was noticed. This indicates that even if there are no significant gross skin manifestations of atrazine this can still produce significant damage to the epidermal barrier and hence can result in increase in penetration of self or other toxic substances.

The modification of acetate and propionate side chains during the biosynthesis of haem and chlorophylls: mechanistic and stereochemical studies

In the conversion of uroporphyrinogen III into protoporphyrin IX and thence into chlorophylls, all eight carboxylic side chains, as well as the four meso positions, are modified, and four enzymes are involved. In the uroporphyrinogen decarboxylase-catalysed reaction all four acetate side chains are converted into methyl groups by the same mechanism, to produce coproporphyrinogen III. Both methylene hydrogen atoms remain undisturbed and the reaction occurs with the retention of stereochemistry. Several questions regarding the enzymology of the decarboxylase are posed. Do all the decarboxylations occur at the same active site and, if so, are the four acetate chains handled in a particular sequence? Is the decarboxylation reaction aided by the transient formation of an electron-withdrawing functionality in the pyrrole ring? Coproporphyrinogen oxidase converts the two propionate side chains of rings A and B into vinyl groups, with an overall anti-periplanar removal of the carboxyl group and the Hsi from the neighbouring position. Evidence is examined to evaluate whether a hydroxylated compound acts as an intermediate in the oxidative decarboxylation reaction. Protoporphyrinogen oxidase then converts the methylene-interrupted macrocycle of protoporphyrinogen IX into a conjugated system. The conversion has been suggested to involve three consecutive dehydrogenation reactions followed by an isomerization step. The face of the macrocycle from which the three meso hydrogen atoms are removed in the dehydrogenation reaction is thought to be opposite to that from which the fourth meso hydrogen is lost during the prototropic rearrangement. In an investigation of the in vivo mechanism for the esterification of the ring D propionic acid group with a C20 isoprenyl group 5-aminolaevulinic acid was labelled with 13C and 18O at C-1 and incorporated into bacteriochlorophyll a. The 18O-induced shift of the 13C resonance in the NMR spectrum showed that both oxygen atoms of the carboxyl group are retained in the ester bond. This and other results suggest that the reaction occurs by the nucleophilic attack of the ring D carboxylate anion on the activated form of an isoprenyl alcohol.

DNA vaccination with VP2 gene of very virulent infectious bursal disease virus (vvIBDV) delivered by transgenic E. coli DH5alpha given orally confers protective immune responses in chickens

The efficacy of different doses of oral DNA vaccines carrying VP2 gene of vvIBDV delivered by E. coli DH5alpha was studied and compared with purified VP2 recombinant expression plasmid DNA vaccine injected intradermally and whole virus vaccine either from homologous virus or from commercial source. The recombinant plasmid pRc-VP2 was transformed in a non-pathogenic strain of E. coli, the DH5alpha and designated as EC/pRC-VP2. Oral immunization of maternal antibody free broiler chickens at 7 and 14-day-old with different dosages of EC/pRc-VP2 elicited specific humoral immune response as measured by ELISA. Protection in different groups was calculated through clinical signs, gross and histopathological lesions, bursa of Fabricius to body weight ratio, humoral and cellular immune responses and mortality in the chickens. Vaccination with EC/pRc-VP2 at the dose rate of 10(9)CFU per chicken conferred 95.4% protection of the chickens against the challenge with homologous virulent field strain of vvIBDV. Protection afforded by attenuated vero cell adapted UAF-06 strain of vvIBDV was comparable (94%) to that by EC/pRc-VP2 and pRc-VP2 vaccines, which was significantly higher (P<0.05) than the protection provided by a commercial attenuated IBDV stain D-78 vaccine (D-78 vaccine was used as positive control due to its frequent use in the field for vaccination of poultry chickens) and other control groups in the study. The results revealed that DNA vaccines against IBDV may be successfully done by adopting bacterial-vectored oral delivery system and vaccination with homologous vvIBDV (UAF-06) conferred significantly higher protection as compared with imported non-homologous commercial IBDV vaccine.

Evaluation of the BAX gel and fluorometric systems for the detection of foodborne Salmonella

The present study compared the sensitivity of the BAX automated fluorometric and the recently discontinued BAX gel electrophoresis systems with a standard culture method to detect Salmonella in 333 high-moisture and 171 low-moisture foods. A total of 95 naturally contaminated foods, including 63 high-moisture and 32 low-moisture foods, were detected by the standard culture method. No contaminated samples were identified exclusively by the BAX systems. By means of the analytical protocol stipulated by the manufacturer, the BAX fluorometric system detected 36 (57.1%) and 29 (90.6%) of the contaminated high- and low-moisture foods, respectively. Similar results were obtained with the BAX gel electrophoresis system, which identified 40 (63.5%) and 26 (81.3%) of the contaminated high- and low-moisture foods. The rate of false-positive reactions with the BAX systems was low. Our results indicate that the low sensitivity of the BAX systems with high-moisture foods, notably raw meats and poultry products, was serovar-independent. The high levels of background microflora that commonly occur in raw meat and on fresh fruit and vegetable products, and the high successive dilutions of test materials for PCR analysis, suggestively undermined the sensitivity of the gel and the fluorometric BAX assays. The potential benefits of immunomagnetic separation of Salmonella in preenrichment cultures, of selective broth enrichment following preenrichment to markedly reduce levels of background microflora in PCR test materials, and the use of larger portions of test materials in PCR analyses should be investigated.

Diagnosis of renal tumors on needle biopsy specimens by histological and molecular analysis

PURPOSE

We diagnosed the subtypes of renal cell carcinoma on needle core biopsies using a combination of histopathology and a molecular diagnostic algorithm.

MATERIALS AND METHODS

Core biopsies were taken of renal tumors following nephrectomy. RNA was extracted and quantitative real-time polymerase chain reaction was performed for 4 gene products to differentiate among renal cell carcinoma subtypes. Histopathological diagnosis was achieved on a second core before and after obtaining the molecular diagnostic algorithm results.

RESULTS

Based on the nephrectomy diagnosis 6 of 77 renal masses were nonneoplastic and 71 were tumors, including 65 renal cell carcinoma/oncocytomas. The overall diagnostic accuracy using histology and our molecular diagnostic algorithm combined was 90.0% (70 of 77). Side by side comparison of histology vs molecular diagnostic algorithm was feasible for 60 classifiable renal cell carcinoma/oncocytomas (31 clear cell, 14 papillary renal cell carcinoma, 6 chromophobe renal cell carcinoma, 2 mucinous tubular and spindle cell carcinoma, and 7 oncocytoma). In this group histology correctly predicted the final histological subtype in 83.3% (50 of 60) of cores. Addition of the molecular diagnostic algorithm to histology improved the subtyping accuracy to 95% (57 of 60), whereas the molecular diagnostic algorithm alone was accurate in 50 of 60 cases (83.3%). Dividing these 60 specimens into clear cell and nonclear cell neoplasms, the addition of the molecular diagnostic algorithm improved the sensitivity for the diagnosis of clear cell carcinoma from 87.1% (27 of 31) to 100% and the negative predictive value from 87.5% to 100%.

CONCLUSIONS

Core biopsies of renal tumors provide adequate material for diagnosing and subtyping renal cell carcinoma. The addition of our molecular diagnostic algorithm to histology improved the diagnostic accuracy of core biopsies of renal masses.

Testicular vasculitis mimicking a testicular neoplasm

Vasculitis of the testis generally presents as a manifestation of systemic vasculitis which is well documented. In isolation, it has only been described on few occasions previously, and hitherto it has been in the young. It often mimics a neoplasm of the testis resulting in radical orchidectomy, only for it to be diagnosed when the specimen is examined under the microscope. In our case, an elderly man presented to us with a presumed testicular neoplasm, however, despite strong clinical and radiological suspicion a testicular vasculitis in isolation was revealed. Following our experience, we performed a literature review and examined all of the cases of testicular vasculitis reported so far and present our findings. We report the general clinical presentation, methods of investigation and subsequent management. This is the first time it has been described in the elderly population.

Primary diagnosis and REAL/WHO classification of non-Hodgkin's lymphoma by fine-needle aspiration: cytomorphologic and immunophenotypic approach

The Revised European American lymphoma (REAL) and World Health Organization (WHO) classification of non-Hodgkin's lymphoma (NHL) relies on the constellation of cytologic, phenotypic, genotypic, and clinical characteristics of NHL. For the most part, the classification does not rely on architectural pattern for classification of neoplasms. This classification makes it possible to diagnose and classify lymphomas by fine-needle aspiration (FNA). In this study, we attempted to evaluate the accuracy of FNA in diagnosing and classifying NHL within the context of the REAL/WHO classifications. Cases included only those in which FNA was the primary diagnosis, followed by a surgical biopsy for confirmation. Flow cytometry (FCM) for phenotyping was carried out whenever material was available. Two groups of pathologists were identified. Group A consisted of pathologists with background training in cytopathology and/or hematopathology (three pathologists). Group B consisted of experienced surgical pathologists with no training in cytopathology and/or hematopathology (four pathologists). Seventy-four cases were included in the study. FCM phenotyping was performed in 53 cases (71%). Large cell lymphoma constituted 63% of the cases. The remaining lymphomas included Burkitt's, small lymphocytic, lymphoblastic, follicle center cell, Ki-1, mantle cell, marginal zone, and natural killer cell lymphoma. The diagnosis of lymphoma was rendered for all cases. The correct classification was seen in 63% of the cases. Classification was more accurate in immunophenotyped than in nonimmunophenotyped cases (84% vs 33%; P = 0.00004). Group A pathologists showed higher incidence of proper classification than group B (80% vs 56%; P = 0.046). The diagnosis and classification of NHL can be achieved in a large number of cases on FNA material. This accuracy can be increased if cytomorphologic criteria are established for different entities of NHL aided by FCM for phenotyping.

Performance of seed germination and growth of Vicia faba L. in fly ash amended soil

The performance of Vicia faba L. in soil amended by different concentrations of fly ash has been studied. The parameters considered are seed germination, growth behaviour and nodulation frequency of the plant. Results revealed that while fly-ash amendment to the soil improved the growth performance at initial stages with application of lower concentrations, it was inhibitory at higher exposure concentrations. Although there was no difference in survival rates, but the seedling growth was reduced in comparison to control plants. Fly ash delayed the nodulation as lesser number of nodules was recorded at higher amendments. Results suggested feasibility of growing V. faba in fly ash contaminated area.