Soil dermatophytes in Madras, India, in relation to human ringworm

A total of 269 soil samples collected from different habitats in Madras, India, were screened for the presence of dermatophytes by the hair-baiting technique. Three strains of Trichophyton mentagrophytes and 16 strains of Microsporum gypseum complex were isolated. These strains were subjected to the mating experiment. 2/3 soil isolates of Trichophyton mentagrophytes belonged to Arthroderma vanbreuseghemii (+) mating type, and 1/3 was Arthroderma vanbreuseghemii (-) mating type. Similarly 6/70 clinical strains of Trichophyton mentagrophytes isolated in our previous study also belonged to Arthroderma vanbreuseghemii (+) mating type. These 6 strains were isolated from severe cases of tinea capitis in children belonging to rural Madras. The teleomorphic and mating type homology between the clinical and soil isolates of T. mentagrophytes suggest that soil may act as reservoir for these organisms. The incompatible clinical strains of T. mentagrophytes var. interdigitale and A. vanbreuseghemii showed DNA homology, thereby establishing the epidemiologic link which supports the above findings.

Isolation of Microsporum nanum from a patient with tinea corporis in Madras, India

Microsporum nanum was isolated from a case of tinea corporis in a 16-year-old boy. This is the first recorded case of human ringworm infection caused by M. nanum in India.

Interaction of apolipoprotein J-amyloid beta-peptide complex with low density lipoprotein receptor-related protein-2/megalin. A mechanism to prevent pathological accumulation of amyloid beta-peptide

Apolipoprotein J (apoJ) has been shown to be the predominant amyloid beta-peptide (Abeta)-binding protein in cerebrospinal fluid. We have previously demonstrated that the endocytic receptor low density lipoprotein receptor-related protein-2/megalin (LRP-2), which is expressed by choroid plexus epithelium and ependymal cells lining the brain ventricles and neural tube, binds and mediates cellular uptake of apoJ (Kounnas, M. Z., Loukinova, E. B., Stefansson, S., Harmony, J. A., Brewer, B., Strickland, D. K., and Argraves, W. S. (1995) J. Biol. Chem. 270, 13070-13075). In the present study, we evaluated the ability of apoJ to mediate binding of Abeta1-40-apoJ complex to LRP-2 in vitro. Immunoblot analysis showed that incubation of apoJ with Abeta1-40 resulted in the formation of Abeta1-40-apoJ complex and the inhibition of the formation of Abeta1-40 aggregates. Using an enzyme-linked immunosorbent assay, an estimated dissociation constant (Kd) of 4.8 nM was derived for the interaction between Abeta1-40 and apoJ. Enzyme-linked immunosorbent assay was also used to study the interaction of the Abeta1-40-apoJ complex with LRP-2. The results showed that Abeta alone did not bind directly to LRP-2; however, when Abeta1-40 was combined with apoJ to form a complex, binding to LRP-2 took place. The binding interaction could be blocked by inclusion of the receptor-associated protein, an antagonist of apoJ binding to LRP-2. When LRP-2-expressing cells were given 125I-Abeta1-40, cellular uptake of the radiolabeled peptide was promoted by co-incubation with apoJ. When the cells were provided purified 125I-Abeta1-40-apoJ complex, the complex was internalized and degraded, and both processes were inhibited with polyclonal LRP-2 antibodies. Furthermore, chloroquine treatment inhibited the cellular degradation of the complex. The data indicate that apoJ facilitates Abeta1-40 binding to LRP-2 and that the receptor mediates cellular clearance of Abeta1-40-apoJ complex leading to lysosomal degradation of Abeta1-40. The findings support the possibility that LRP-2 can act in vivo to mediate clearance of the complex from biological fluids such as cerebrospinal fluid and thereby play a role in the regulation of Abeta accumulation.

Scatter factor/hepatocyte growth factor expression enhances human glioblastoma tumorigenicity and growth

We have shown previously that the multifunctional cytokine scatter factor/hepatocyte growth factor (SF/HGF) is elevated in human malignant gliomas. In this study we investigated how human SF/HGF expression affects the malignancy of the U373 human glioblastoma cell line in vivo and in vitro. Human SF/HGF gene transfer increased U373 glioblastoma tumorigenicity by > or = 20-fold and enhanced the growth rate of intracerebral U373 xenografts by 3- to 8-fold. SF/HGF expression had no effect on the proliferation of glioblastoma cell monolayers but increased their anchorage-independent colony formation in soft agar by 5- to 8-fold. These results are the first to show that SF/HGF expression by human glioblastoma cells enhances their growth dysregulation in vitro and malignancy in vivo.

Dry mixing technique for the large scale production of iodine fortified salt in India

Dry mixing technique was used successfully in three factories in India for the manufacture of iodine fortified salt. Permitted food additives, calcium carbonate and magnesium carbonate, were used with potassium iodate. The technology was smooth and free from any problem. Since the formerly conventional, but now superceded on analytical performance criteria, spray-mixing system was not used in the study, plants of the economics either batch mixing or continuous processes were more in evidence, and could be compared with avoidable spray mixing production performance data. The iodine fortified salt was free-flowing and retained the colour of the common salt. The iodine distribution was uniform (about 30 ppm). Long distance road transportation did not affect the iodine stability and its consistency. Storage studies showed satisfactory stability and the fortified salt had prolonged shelf-life beyond one year.

Predicted structure of the extracellular region of ligand-gated ion-channel receptors shows SH2-like and SH3-like domains forming the ligand-binding site

Fast synaptic neurotransmission is mediated by ligand-gated ion-channel (LGIC) receptors, which include receptors for acetylcholine, serotonin, GABA, glycine, and glutamate. LGICs are pentamers with extracellular ligand-binding domains and form integral membrane ion channels that are selective for cations (acetylcholine and serotonin 5HT3 receptors) or anions (GABAA and glycine receptors and the invertebrate glutamate-binding chloride channel). They form a protein superfamily with no sequence similarity to any protein of known structure. Using a 1D-3D structure mapping approach, we have modeled the extracellular ligand-binding domain based on a significant match with the SH2 and SH3 domains of the biotin repressor structure. Refinement of the model based on knowledge of the large family of SH2 and SH3 structures, sequence alignments, and use of structure templates for loop building, allows the prediction of both monomer and pentamer models. These are consistent with medium-resolution electron microscopy structures and with experimental structure/function data from ligand-binding, antibody-binding, mutagenesis, protein-labeling and subunit-linking studies, and glycosylation sites. Also, the predicted polarity of the channel pore calculated from electrostatic potential maps of pentamer models of superfamily members is consistent with known ion selectivities. Using the glycine receptor alpha 1 subunit, which forms homopentamers, the monomeric and pentameric models define the agonist and antagonist (strychnine) binding sites to a deep crevice formed by an extended loop, which includes the invariant disulfide bridge, between the SH2 and SH3 domains. A detailed binding site for strychnine is reported that is in strong agreement with known structure/function data. A site for interaction of the extracellular ligand-binding domain with the activation of the M2 transmembrane helix is also suggested.

Immunohistochemical analysis of beta-tubulin isotypes in human prostate carcinoma and benign prostatic hypertrophy

BACKGROUND

beta-tubulin, the intracellular target of several antimicrotubule agents, is encoded by at least six genes and exists as multiple isotypes with tissue-specific expression. Previous in vitro studies indicated that tubulin isotype composition may affect polymerization properties, dynamics, and sensitivity to drugs.

METHODS

To investigate the isotype composition of beta-tubulin in human prostate, tissues were collected from 26 patients after radical prostatectomy and sections were stained with isotype-specific antibodies.

RESULTS

beta IV tubulin is the predominant isotype in benign prostatic hyperplasia (BPH) and adenocarcinoma, showing significantly stronger immunohistochemical expression than beta II and beta III, particularly in Gleason's grade 3 and 4 cancers. Staining for the beta II isotype was invariably weak and often absent in BPH and normal glands. There was a marked increase in beta II isotype stain from BPH to cancer in 77% of the patients, suggesting that the expression of this isotype is related to malignant status.

CONCLUSIONS

The beta II tubulin isotype is a potential marker for prostate adenocarcinoma. The possibility that tumor beta-tubulin isotype composition may effect the response to antimicrotubule drug therapy in prostate cancer and other tumors merit investigation.

Interaction of estramustine with tubulin isotypes

The interaction of the antimitotic agent estramustine with bovine microtubule proteins and purified tubulin was investigated. Direct photoaffinity labeling of microtubule protein with [14C]estramustine resulted in the labeling of both alpha- and beta-tubulin, and this was inhibited with unlabeled estramustine in a dose-dependent manner. [14C]Estramustine was incorporated into both the soluble and polymerized forms of tubulin. The affinity constant for estramustine binding to tubulin was determined by equilibrium dialysis to be 23 +/- 5 mM. Estramustine did not affect [3H]vinblastine binding, and vinblastine had no effect on direct labeling with [14C]estramustine. Both rhizoxin and paclitaxel decreased the covalent labeling of tubulin with [14C]estramustine in a dose-dependent fashion and were noncompetitive inhibitors of the binding of estramustine to tubulin. The binding of colchicine to tubulin was not inhibited by estramustine as detected by fluorescence and DEAE filter assays. The estramustine binding site on tubulin is therefore distinct from that of colchicine and vinblastine and may at least partially overlap with the binding site for paclitaxel. In both bovine brain microtubules and cytoskeletal proteins from human prostatic carcinoma cells, the incorporation of [14C]estramustine into the beta III isotype of tubulin was found to occur with a reduced efficiency compared to that of the other beta-tubulin isotypes and alpha-tubulin. Since this isotype is overexpressed in estramustine resistant human prostate carcinoma cells, these results indicate that beta III-tubulin may play a role in the response to the effects of estramustine.

ABO blood groups in relation to the infection rate of dermatophytosis

The role of ABO blood groups in the carriage rate of dermatophytosis was studied. Blood grouping was done for 108 culture-proven dermatophytosis patients. Forty-nine patients belonged to blood group A, 54 to blood group O, three to blood group B and two to blood group AB. The incidence of dermatophytosis was found to be high in patients of blood group O and A. However, chronicity of the disease was more frequent in those in blood group A. The control group consisted of 100 healthy subjects. Sixteen out of 29 control subjects belonging to blood group A had a history of skin infections. None of the O blood group control subjects had a history of skin infections. Our study suggests that A blood group subjects may be prone to chronic dermatophytosis.

Effect of tumor necrosis factor-alpha on basal and insulin-stimulated glucose transport in cultured muscle and fat cells

It has been reported that tumor necrosis factor-alpha (TNF-alpha) inhibits insulin action in adipocytes and plays an important role as mediator of insulin resistance in non-insulin-dependent diabetes. The effect of this cytokine on insulin action in muscle, which is responsible for 80% of the glucose disposal in the body, has not been studied. Therefore, we examined the effect of TNF-alpha on basal and insulin-mediated transport of 2-deoxy[3H]-glucose in L6 rat muscle cells. TNF-alpha treatment for 5 days up to a concentration of 20 ng/mL or 8 days at 10 ng/mL did not inhibit the insulin-stimulated increase in deoxyglucose transport in L6 cells. However, there was a significant increase in basal transport in TNF-alpha- treated cells. Comparative experiments with 3T3-L1 adipocytes showed that in cells cultured with insulin, TNF-alpha decreased basal transport but the insulin-stimulated increase was unaffected. In cells cultured without insulin, basal transport was slightly increased and the insulin-stimulated increase in transport was decreased by approximately 60% but the cell protein was decreased by approximately 60%, suggesting cytotoxicity. Cells cultured without insulin were more sensitive to inhibition of 14C-alanine incorporation into proteins by low concentrations of TNF-alpha compared with cells cultured with insulin. These results suggest that TNF-alpha affects glucose metabolism, causing increased basal uptake in muscle cells and decreased uptake in adipocytes. TNF-alpha appears to affect general cell metabolism, including glucose transport in adipocytes, and not specifically insulin-stimulated glucose transport.

Renal amyloidosis--a clinicopathologic study

A total of 19,075 necropsies and 1169 renal biopsies were scrutinised over a period of 20 years (1973-1992) retrospectively with an aim to study the incidence and pattern of renal amyloidosis in Nair Hospital. A total of 75 cases with amyloidosis were detected, 33 from the necropsy series (0.162%) and 42 from biopsies (3.59%). Secondary amyloidosis was seen in 82.66% and primary amyloidosis in 10.66%. Tuberculosis of various organs was the main cause of secondary amyloidosis (79.03%). Nephrotic syndrome was the common mode of presentation (52%). Besides kidney, which were involved in all cases, the liver, spleen and adrenals were other commonly involved organs at necropsy. Renal failure was the leading cause of death (51.51%). Thioflavine-T proved to be more sensitive technique than other conventional staining methods. The potassium permanganate test is a useful test to distinguish secondary amyloid fibrils from other amyloid fibrils. Abdominal fat aspiration may prove to be specific, sensitive and a routine procedure enabling the early diagnosis of amyloidosis leading to increased incidence of amyloidosis during life than at necropsy.

Increase of beta(III)- and beta(IVa)-tubulin isotopes in human prostate carcinoma cells as a result of estramustine resistance

Estramustine (EM), an antimicrotubule agent, is effective against hormone-refractory prostate cancer when used in combination with vinblastine or paclitaxel. To understand the effect of EM on beta-tubulin, a cellular target for this class of drugs, human prostate carcinoma cells (DU-145) were made resistant to EM, and two cell lines were selected at 12- (EM-12) and 15-microMolar (EM-15) concentrations of the drug. These cell lines exhibited 8- to 9-fold resistance to EM and 2- to 4-fold cross-resistance to paclitaxel. Immunofluorescent staining of the cells with beta-tubulin isotype-specific antibodies showed an approximately 6-fold increase in the beta(III)-tubulin levels and moderate increase in overall beta-tubulin levels in EM-resistant cells when compared to DU-145 cells. This increase of beta(III) isotype was confirmed by Western analysis. A reverse transcriptase-PCR assay was also employed using beta-tubulin isotype-specific primers to quantify beta-tubulin isotype RNA. A 4-fold increase in beta(III) and a 3-fold increase in beta(IV alpha) transcript were seen in both EM-resistant cell lines. These results indicate that overexpression of specific beta-tubulin isotypes may play a role in the cellular defense against EM and other antimicrotubule agents.

Mating patterns of dermatophytes of diverse origin in India

The mating patterns of Trichophyton mentagrophytes var. interdigitale (74 isolates) and the Microsporum gypseum complex (17 isolates) of diverse origin and T. rubrum (25 isolates) and T. tonsurans (10 isolates) of clinical origin were studied. The results of the study showed that the teleomorph of the Indian isolates of T. mentagrophytes belong to Arthroderma vanbreuseghemii, undetermined teleomorphs of T. mentagrophytes var. interdigitale (+) mating types, and undetermined teleomorphs of T. mentagrophytes var. interdigitale indeterminate mating types. All the isolates of T. rubrum and T. tonsurans were found to be of the (-) mating type.

Minipreparation of total cellular DNA is useful as an alternative molecular marker of mitochondrial DNA for the identification of Trichophyton mentagrophytes and T. rubrum

Total cellular DNA was extracted from 18 isolates of Trichophyton mentagrophytes and six isolates of unidentified Trichophyton species taken from tinea corporis, tinea cruris and tinea pedis patients by a minipreparation method. The DNA was digested with the restriction enzymes HaeIII and MspI, followed by electrophoresis on agarose gels. The restriction enzyme profiles of the DNAs were compared with those of mitochondrial (mt) DNA extracted from reference strains of T. mentagrophytes (Arthroderma simii, A. benhamiae and A. vanbreuseghemii) and T. rubrum. All 18 T. mentagrophytes isolates showed the same DNA profiles as mtDNA from A. vanbreuseghemii. The six unidentified Trichophyton isolates exhibited DNA profiles the same as that of mtDNA from T. rubrum. Consequently, these isolates were identified as T. rubrum. In conclusion, restriction enzyme analysis of total cellular DNA prepared by the minipreparation method is considered to be useful as an alternative method of mtDNA analysis and is helpful for the identification of these dermatophyte species.

Human requirements of iodine & safe use of iodised salt

Iodine deficiency is the most common preventable cause of mental deficiency. Remarkable success has been achieved by the use of iodised salt to correct this deficiency in many industrialised countries since 1920. The Government of India has adopted a strategy to iodise all edible salt in the country to overcome iodine deficiency. Universal salt iodisation is the principal public health measure for eliminating iodine deficiency disorders. Daily iodine intakes of up to 1000 micrograms, appear to be entirely safe. In India, the likelihood of exceeding this level is quite small. Iodised salt does not cause any side effects. Iodine in iodised salt does not carry risks for persons who are already iodine sufficient. iodisation of salt at the current level of fortification (15-30 ppm iodine) keeps intakes well within a safe daily range for all populations, irrespective of their iodine status.

Leptin levels in human and rodent: measurement of plasma leptin and ob RNA in obese and weight-reduced subjects

Leptin, the gene product of the obese gene, may play an important role in regulating body weight by signalling the size of the adipose tissue mass. Plasma leptin was found to be highly correlated with body mass index (BMI) in rodents and in 87 lean and obese humans. In humans, there was variability in plasma leptin at each BMI suggesting that there are differences in its secretion rate from fat. Weight loss due to food restriction was associated with a decrease in plasma leptin in samples from mice and obese humans.

Influence of ethacrynic acid on glutathione S-transferase pi transcript and protein half-lives in human colon cancer cells

Ethacrynic acid (EA) is a plant phenolic acid that is both an inhibitor and an inducer of glutathione S-transferase (GST) activity. To determine contributory factors in the increased GST activity caused by EA treatment, human colon carcinoma HT29 cells were compared with a cloned EA-resistant population (HT6-8) maintained in medium containing 72 microM EA. Several factors are involved in the increased expression of GST pi in HT6-8. For example, nuclear run-on experiments showed an approximately 2-fold increase in the rate of transcription of GST pi. In addition, the half-life of GST pi transcript was increased from 4.1 (wild type, HT29, HT4-1) to 8.4 hr. The half-life of GST pi protein was 1-2 hr in HT4-1 cells versus 8-9 hr in HT6-8 cells. When either human ovarian carcinoma cells (SKOV3) or human prostatic carcinoma cells (DU145) were treated with EA, the half-life of the GST pi transcript was also increased. The transcript half-lives of another thiol-metabolism enzyme, gamma-glutamylcysteine synthetase (gamma-GCS), and a phase II detoxification enzyme, dihydrodiol dehydrogenase (DDH), were also increased in HT6-8, SKOV3 and DU145 cells treated with EA. However, the half-lives of transcripts from "housekeeping genes," such as glyceraldehyde 3-phosphate dehydrogenase (G3PDH), beta-actin and beta-tubulin, were not changed in these cell lines following EA. Apparently, a number of coordinated factors are involved in EA-enhanced expression of GST pi and other detoxification enzymes.

Iodised salt is safe

Iodine deficiency disorders are prevalent in all the States and Union Territories in India. Under the National Iodine Deficiency Disorders control programme, the Government of India has adopted a strategy to iodisation of all edible salt in the country which is a long term and sustainable preventive solution to eliminate iodine deficiency disorders. The benefits to be derived from universal salt iodisation are more to the population. Iodised salt is safe and does not cause any side effect.

Glyoxalase I in detoxification: studies using a glyoxalase I transfectant cell line

The glyoxalase system (glyoxalase I, glyoxalase II and GSH as cofactor) is involved in the detoxification of methylglyoxal (a byproduct of the glycolytic pathway) and other alpha-oxoaldehydes. We have transfected a 622 bp cDNA encoding human glyoxalase I into murine NIH3T3 cells. The recipient cells were shown to express elevated transcript and protein levels and a 10-fold increase in glyoxalase I enzyme activity. This was accompanied by an increased tolerance for exogenous methylglyoxal and enhanced resistance to the cytotoxic effects of two glyoxalase I inhibitors (s-p-bromobenzylglutathione diethyl ester and s-p-bromobenzylglutathione dicyclopentyl ester), a glutathione analogue [gamma-glutamyl-(S)-(benzyl)cysteinyl-(R)-(-)-phenylglycine diethyl ester] and the anti-cancer drugs mitomycin C and adriamycin. Steady-state levels of GSH were significantly lower in the transfected cells, perhaps reflecting increased flux as a consequence of elevated glyoxalase activity. This decrease did not alter the sensitivity to the alkylating agent chlorambucil. Although transfection did not affect the growth or doubling time of the NIH3T3 cells, analysis of glyoxalase I activity showed a consistent increase in tumour tissue when compared with pair-matched controls. Thus increased glyoxalase I is associated with the malignant phenotype and may also contribute to protection against the cytotoxicity of certain anti-cancer drugs.