Tubular hypertrophy due to work load induced by furosemide is associated with increases of IGF-1 and IGFBP-1

We have examined the expression of insulin-like growth factor 1 (IGF-1), IGF binding protein-1 (IGFBP-1), and IGF binding protein-3 (IGFBP-3) in the rat distal nephron during increased cell work load and hypertrophy, induced by the diuretic, furosemide. Furosemide was given for six days to increase distal sodium delivery and uptake. To mitigate salt loss, the animals drank 0.8% NaCl and 0.1% KCl. Control rats were infused with vehicle (0.9% saline) and drank tap water. Furosemide increased urinary volume (13-fold) and sodium excretion (eightfold), and decreased urine osmolarity (fourfold). By immunocytochemistry, staining for IGF-1 and IGFBP-1 was markedly increased in distal convoluted tubules and cortical collecting ducts; both segments also underwent hypertrophy. Increased staining for the peptides was evident early (1 hr, 18 hr) after furosemide, prior to hypertrophy of cells. Whereas transcripts of IGF-1 and IGFBP-3 mRNA showed little or no increase in extracts from furosemide-treated kidney cortices, IGFBP-1 mRNA was increased threefold 18 hours after furosemide. Alterations of IGF-1 and IGFBP-1 were independent of changes in plasma aldosterone, glucocorticoids or arginine vasopressin. That IGFBP-1 mRNA increased threefold without significant changes in IGF-1 mRNA suggests that hypertrophic stimuli might initially induce the synthesis of IGF binding protein followed by the trapping of extracellular IGF-1. The present study raises the possibility of IGF-1 and IGFBP-1 being involved in processes that lead to tubular hypertrophy. IGFBP-1 may regulate these effects by binding to and interaction with IGF-1.

Nuclear factor kappa B functions as a negative regulator for the rat androgen receptor gene and NF-kappa B activity increases during the age-dependent desensitization of the liver

Transcriptional regulation of the steroid hormone receptor genes plays a central role in temporal changes of target cell sensitivity during development, maturation, and aging. Sequence-specific DNA-protein interactions mediate these regulatory functions. Progressive 5' deletion of the rat androgen receptor (rAR) gene immediately beyond the -572 base pair (bp) region causes a marked increase in its promoter activity. DNase I footprinting with nuclear proteins revealed a protected area encompassing -574- to -554-bp positions that begins with a perfectly palindromic nuclear factor kappa B (NF-kappa B) motif. Electrophoretic mobility shift analyses (EMSA) showed that the decameric rAR NF-kappa B site at positions -574 to -565 cross-competes with the authentic kappa immunoglobulin light chain enhancer for specific protein binding. Supershift with specific antibodies to NF-kappa B subunits confirmed that the two retarded bands observed in the EMSA with the labeled rAR probe are due to p50/p65 and p50/p50 dimers of the NF-kappa B/Rel proteins. Fragments of rAR promoter with either deletion or point mutation of the NF-kappa B site are found to be about 2- to 3-fold more effective as compared to the wild type control in driving a heterologous reporter gene in cellulo. Thus, unlike most other known cases, NF-kappa B acts as a negative regulator for the rAR gene. The physiological relevance of this repressor function is evident from a 10-fold increase in the p50/p50 form of the NF-kappa B activity in the liver of aged rats exhibiting hepatic androgen desensitization. The newly identified repressor element is a rare example of a naturally occurring perfect palindromic binding motif for the NF-kappa B/Rel family of transcription factors. This repressor factor and the positively acting age-dependent factor, ADF, described earlier (Supakar, P. C., Song, C. S., Jung, M. H., Slomczynska, M. A., Kim, J.-M., Vellanoweth, R. L., Chatterjee, B. & Roy, A. K. (1993) J. Biol. Chem. 268, 26400-26408) function to coordinate the tissue-specific down-regulation of the rAR gene during aging.

Androgen action

Androgens are C-19 steroids that provide major regulatory influences on male reproductive function. Testosterone, the principal androgenic steroid, is secreted by the Leydig cells of the testes. Both testosterone and its 5 alpha reduced derivative 5 alpha-dihydrotestosterone (DHT) are physiological ligands for the androgen receptor (AR). Ligand-activated AR acts as a nuclear transcription factor and mediates androgen action. AR, along with receptors for a number of C-21 steroids such as glucocorticoid, mineralocorticoid, and progesterone, share the same 15 base pair consensus element composed of 5'-GGA/TACAnnnTGTTCT-3'. Despite this cross-reactivity at the level of the DNA, physiologically, androgens regulate their target genes with a high degree of receptor specificity. Such a regulatory specificity appears to be due to multiphasic interactions involving enzymatic activation/inactivation of the steroid ligand, interaction with specific receptor-associated nuclear factors on or around the hormone response element, and differential regulation of the receptor gene expression. Conversion of testosterone to 5 alpha-dihydrotestosterone in target cells is a widespread activation mechanism that amplifies the androgenic signal. Unlike the testosterone-AR complex, DHT-activated AR has a longer half-life, and thus prolongs androgen action. Oxido-reduction of androgens by 17 beta-hydroxysteroid dehydrogenase and sulfurylation by androgen sulfotransferase are two major pathways of androgen inactivation in target cells. Prenatal deprivation of androgen action, due to mutations in either the AR or the 5 alpha-reductase gene, results in developmental abnormalities of male reproductive tissues and also cause partial or complete androgen-insensitivity syndromes. Elucidation of various molecular steps in androgen action is allowing development of improved therapeutic agents for the management of disorders of androgen action such as the prostatic hypertrophy and neoplasia.

Development of methods to monitor exposure to 1-nitropyrene

On the basis of 32P-postlabeling analysis, treatment of rats with 1-nitropyrene (1-NP) resulted in the formation of multiple DNA adducts in the liver, mammary glands, and peripheral lymphocytes. The one adduct resulting from nitroreduction, N-(deoxyguanosin-8-yl)-1-aminopyrene, constitutes only a minor component among the adducts. In the present study, incubation of calf thymus DNA with mutagenic ring-oxidized metabolites of 1-NP in vitro in the presence and absence of xanthine oxidase also resulted in the formation of multiple adducts. On the basis of their chromatographic behavior, it appears that DNA adducts derived from such metabolites may have been formed in vivo; however, this needs to be confirmed. [3H]1-NP was given to male and female F344 rats and Sprague-Dawley rats by gavage at five dose levels in the range of 0.1 to 1000 micrograms/kg bw. This led to stable hemoglobin adducts accounting for 0.08 +/- 0.05% of the dose (n = 3 rats). The radioactivity associated with hemoglobin following administration of [3H]1-NP was cleared with a half-life of about 14 days, which is faster than that of unmodified erythrocytes in the rat (t1/2 = 30 days). Treatment of the hemoglobin with 1% HCl in acetone, to precipitate the globin, released the radioactivity; it was all bound to the heme moiety. The structures of the heme adducts have not been elucidated; yet, because of their stability, they may be useful as dosimeters for human exposure to 1-NP.(ABSTRACT TRUNCATED AT 250 WORDS)

EVALUATION OF NON-CARDIAC CHEST PAIN

A series of five cases of non-cardiac chest pain is being reported. In all cases, a detailed cardiac work up excluded coronary artery disease (CAD). Upper gastro-intestinal endoscopy was found to be useful. Gastro esophageal reflux disease (GERD) was diagnosed in three cases. The diagnosis of esophageal disease was clinical in the other two. All patients responded well to further treatment and have been followed up for six months to two years.

Reentry monitoring in the treatment of physicians with substance dependence

A total of 37 physicians and other health care professionals have been accepted into a monitoring and advocacy program for an average of 24 months. Thirty-five are working in their profession, one is in treatment, and one has repeatedly relapsed and is no longer practicing medicine (an overall improvement rate of 97%). The elements of "reentry monitoring" are identified and proposed as a standard for the treatment of physicians with substance dependence.

Androgen and estrogen sulfotransferases of the rat liver: physiological function, molecular cloning, and in vitro expression

Cloning of the androgen and estrogen sulfotransferases has allowed studies on their spatiotemporal regulation and physiological function. These two enzymes appear to be involved in regulating target cell sensitivity for the androgenic and estrogenic steroids. Recombinant androgen sulfotransferase produced in insect Sf9 cells through a baculoviral expression vector is capable of transferring the sulfate from PAPS (phosphoadenosine phosphosulfate) to 3 alpha, 3 beta, 17 alpha, and 17 beta hydroxyl groups of a number of steroid substrates indicating a broad range of substrate specificity.

Biomonitoring of nitropolynuclear aromatic hydrocarbons via protein and DNA adducts

Nitropolynuclear aromatic hydrocarbons (nitro-PAHs) are widely distributed in the environment. For several chemicals in this class of compounds, mutagenic activity in bacterial and mammalian systems and tumorigenic activity in laboratory animals have been clearly documented. Procedures for assessing the risk to humans from exposure to nitro-PAHs have not been clearly defined, despite the wide-spread occurrence of such agents in the environment and their possible involvement in the etiology of some human cancers. Several methods are available for determining exposure, uptake, and metabolic activation of genotoxic carcinogens in humans. DNA adducts currently are regarded as the most direct markers of genotoxicity. However, several proteins are equally capable of forming adducts with electrophiles derived from xenobiotics. We focused on developing methods to detect and quantify adducts of 1-nitropyrene and 1,6-dinitropyrene with proteins and with DNA. 1-Nitropyrene is the most abundant nitro-PAH in emissions from combustion sources such as diesel engines. Although 1,6-dinitropyrene is far more mutagenic and more tumorigenic than 1-nitropyrene, it is present in the environment at lower levels. Seeking a highly sensitive method, we have utilized the 32P-postlabeling technique to establish the pattern of the DNA adducts formed in rat tissues, as well as in peripheral blood lymphocytes, following administration of both 1-nitropyrene and 1,6-dinitropyrene. We also present results on hemoglobin and albumin adducts formed after administration of these nitro-PAHs. [3H]1-Nitropyrene was given to male or female Fischer-344 or Sprague-Dawley rats by gavage at five dose levels ranging from 0.1 to 1,000 micrograms/kg of body weight. This led to stable hemoglobin adducts, which accounted for 0.08% +/- 0.05% of the dose. The radioactivity associated with hemoglobin following administration of [3H]1-nitropyrene was cleared with a half-life of 13.6 days. This is faster than the clearance of unmodified erythrocytes in the rat (half-life of 30 days). Treating the hemoglobin with 1% hydrochloric acid in acetone, to precipitate the globin, released the radioactivity so that none remained bound to the globin. Rather, the radioactivity remained bound to the heme moiety. To obtain structural information about the heme adducts, we incubated [3H]1-nitrosopyrene and [3H]4,5-epoxy-4,5-dihydro-1-nitropyrene with rat hemoglobin. In each case, [3H] was bound mainly to globin and, to a lesser extent, to the heme moiety.(ABSTRACT TRUNCATED AT 400 WORDS)

Albendazole therapy for neurocysticercosis

Based on clinical evaluation and computed tomography (CT) of the brain, 30 cases of neurocysticercosis were diagnosed. Diagnosis was supported by presence of histopathologically proven subcutaneous cysticerci in 12 cases. Three primary neurological syndromes were established i.e. epilepsy in 22 cases, increased intracranial tension in 6 cases and meningoencephalitis in 2 cases. Albendazole was administered orally in a dose of 15 mg/kg bodyweight/day for 30 days without prophylactic steroids. Follow up CT study at 3 months and 12 months revealed complete regression of all lesions in 2 cases, partial regressions in 14 cases and change in morphology in 4 cases. Transient appearence of fresh subcutaneous cysticerci as a side effect of therapy was noted in 4 cases. Albendazole, though acting slow, is considered a suitable alternative to praziquantel in medical management of parenchymal neurocysticercosis.

In vitro analysis of the interaction between sucralfate and ketoconazole

In healthy volunteers, the bioavailability of ketoconazole is significantly decreased during simultaneous administration with sucralfate. In an effort to address this problem, we examined the interaction between sucralfate and ketoconazole in aqueous solutions and in simulated gastric fluid (SGF) at various initial pHs (1, 2, 3, and 6) in the presence or absence of glutamic acid hydrochloride (GA). Samples from each solution were taken 30 min and 2 h after the addition of ketoconazole to evaluate the solubility of ketoconazole over the usual time period of maximal absorption of ketoconazole in humans. The addition of GA to SGF leads to an increase in solution acidity, while the pHs of SGF at a pH of 1, 2, or 3 are markedly increased by the addition of sucralfate. There is a net decrease in acidity from initial pHs for the pH 1, 2, and 3 solutions when GA and sucralfate are combined. The concentration of ketoconazole in SGF at pHs of 1, 2, 3, 4, and 6 was evaluated in order to assess the pH-dependent solubility properties of the drug in the absence of other interacting species. Regardless of the initial pH, combinations of GA plus ketoconazole showed high concentrations of ketoconazole (approximately 100%) in solution. In contrast, significant decreases in the concentration of soluble ketoconazole were observed when sucralfate was mixed with ketoconazole, and, in some cases, soluble ketoconazole was not detectable. The addition of GA to a mixture of sucralfate and ketoconazole leads to a significant increase in the concentration of solubilized ketoconazole. Nonetheless, important sucralfate-ketoconazole interactions are still observed. After 2 h, approximately 35% of the maximal ketoconazole concentration remained in solution. Comparison of the ketoconazole concentrations at different pHs with the predicted concentrations of the three protonation species of ketoconazole [H2(ketoconazole)(2+), H(ketoconazole)(+), or ketoconazole] showed no correlation. Therefore, the decrease in ketoconazole solubility is not simply a reflection of pH perturbation associated with the dissolution of sucralfate. The observed data are most consistent with a model that has H2(ketoconazole)(2+) or H(ketoconazole)(+) forming an electrostatic interaction with the sucralfate polyanion. The findings of this study suggest that the coadministration of sucralfate with other azole antifungal agents should be investigated.

A novel regulatory element associated with age-dependent expression of the rat androgen receptor gene

A large body of evidence indicates that the genetic program of aging has co-evolved with the sexual mode of reproduction (Partridge, L., and Barton, N. H. (1993) Nature 362, 305-311). Age-dependent changes in target cell sensitivity to reproductive hormones can be considered part of this evolutionary linkage. Here we describe a novel regulatory element in the rat androgen receptor (AR) gene promoter associated with its age-dependent expression in the liver. This element consists of two (19 and 25 base pairs) contiguous sites, one specifically binding an Age-dependent Factor (ADF) and the other an Associated Factor (AF). Both deletion and point mutations of the ADF site result in about a 5-fold decline in the AR promoter function. Unlike AF, which is relatively tissue specific, ADF appears to be ubiquitous. The ubiquitous and evolutionarily conserved nature of ADF suggests a fundamental role of this novel transcription factor in programmed gene expression.

A distal activation domain is critical in the regulation of the rat androgen receptor gene promoter

The far upstream region of the rat androgen receptor (AR) gene has been cloned, and the nucleotide sequence up to -2656 bp established. Nested deletion mutants of rat AR 5' flanking sequences were ligated to the luciferase reporter gene, and their promoter activities were examined in transfected COS1 cells. Results show a critical cis-acting domain located between positions -960 and -940. Deletion of this cis element resulted in a greater than 90% decrease in the promoter activity. A nuclear protein that specifically binds to this 21-nucleotide sequence was identified by gel mobility shift analysis. The -960/-940 cis element has no identify to the binding sequence of any known transcription factor. Furthermore, the cognate binding protein is present in both rat and human (HeLa) cell nuclear extracts. We conclude that a novel trans-activator interacting at the -960/-940 region plays a critical role in the regulation of AR gene expression.

Zinc supplementation in protein energy malnutrition

A pair-matched controlled study was done with 30 children (15 males, 15 females) of mild to moderate PEM in test and equal number in control groups, aged 8-24 months old. At the beginning, in both test and control groups parents were advised to provide sufficient amount of home cooked foods so that the child received on an average 100-150 Kcal/kg/day of energy and 2-3 g/kg/day of protein. Vitamin supplements were provided to all children in both groups. In addition, the test group received a supplementation of 5.625 mg of elemental zinc daily orally while controls received a placebo. Evaluation at the end of 3 months showed that children in test group had a weight gain of 3.742 +/- 0.488 kg against 2.035 +/- 0.383 kg of the control group. Similarly, weight velocity was 5.752 +/- 0.818 g/kg/day in test group against 3.153 +/- 0.617 g/kg/day of the control group. These differences in weight gain and weight velocity were highly significant (p < 0.001). Serum zinc levels, initially and at the end of study were 87.5 +/- 9.6 micrograms/dl and 121.0 +/- 10.1 micrograms/dl, respectively in test group in comparison to 91.2 +/- 9.8 micrograms/dl and 91.0 +/- 10.1 micrograms/dl in controls. This difference was also highly significant (p < 0.001). The daily total calorie intake remained comparable in both groups. Our observations suggest that zinc supplementation during nutritional rehabilitation of mild to moderate PEM hastens the recovery.

Phenytoin-induced chronic hepatitis

Phenytoin has been associated with acute hepatotoxicity. Chronic liver enzyme abnormalities associated with phenytoin have been attributed to enzyme induction. There have been no reports of phenytoin-induced chronic hepatitis. We describe an asymptomatic 52-year-old woman who received phenytoin sodium for 11 years and was found to have elevated serum aminotransferases. Assays for hepatitis A, B, and C were negative. Liver biopsy was performed and showed chronic persistent hepatitis. This documentation of phenytoin-induced chronic persistent hepatitis was proven by histology and its etiology confirmed by drug withdrawal and by rechallenge. Although uncommon, this entity is important to recognize in the differential diagnosis of asymptomatic chronic hepatic enzyme dysfunction.

Study of photodynamic reactions of p-nitroacetophenone using ESR and optical techniques

The photosensitizing properties of p-nitroacetophenone (PNAP), a well-known radiosensitizer, have been studied in near UV region. The mechanism of PNAP photosensitization has been investigated by testing the efficiency of singlet oxygen production using photooxidation of 2,2,6,6-tetramethylpiperidine (TEMP) and photodegradation of guanosine. In both the cases, the enhancement effect of deuterated solvents has been observed. Results of these experiments suggest the significant role of type II mechanisms in PNAP photosensitization.

Relative efficiency of Phyllanthus emblica fruit extract and ascorbic acid in modifying lead and aluminium-induced sister-chromatid exchanges in mouse bone marrow

The identification of desmutagens and bioantimutagens in plants has prompted the search for additional plant extracts capable of modifying adverse cellular effects of environmental toxicants. The protective action of crude extracts of Phyllanthus emblica fruits (PFE) against lead (Pb) and aluminium (Al)-induced sister chromatid exchanges (SCEs) was studied in bone marrow cells of Mus musculus. The modifying effect of the crude extract was compared with that of comparable amounts of synthetic ascorbic acid (AA), a major component of the fruits. Oral administration of PFE or AA for 7 consecutive days before exposure of mice to the metals by intraperitoneal injections reduced the frequencies of SCEs induced by both metals. PFE afforded a more pronounced protective effect than AA in counteracting the genotoxicity induced by both Al and Pb: This difference was significant with Pb. The higher protection afforded by PFE may be attributed to the interaction of AA with other natural ingredients present in the crude fruit extract.

Peripartum cerebral venous thrombosis

The clinical and computed tomography (CT) features of 25 patients with peripartum CVT are described. Majority of the patients presented in postpartum period and did not receive proper antenatal care. Headache (92%), altered sensorium (80%, seizures (76%), papilloedema (80%) and hemiplegia (52%) were the common modes of presentation. CT findings included diffuse brain oedema (52%), haemorrhagic or nonhaemorrhagic infarctions on one or both sides of brain (48%), gyral enhancement (40%) and tentorial enhancement (16%). While 15 patients made good recovery, 3 cases (12%) died during acute stage of illness.

Spatio-temporal expression of estrogen sulfotransferase within the hepatic lobule of male rats: implication of in situ estrogen inactivation in androgen action

Estrogen sulfotransferase (EST) catalyzes transfer of the sulfate group from phosphoadenosine phosphosulfate to estrogenic steroids. Since estrogen sulfates do not bind to the estrogen receptor with high affinity, EST can control the intracellular level of the receptor-active estrogens. Androgen action in the rat liver, as indicated by the androgenic induction of alpha 2u-globulin, is inhibited by low levels of estrogens. Thus, in situ estrogen inactivation by EST is expected to increase hepatic androgen sensitivity. During the lifespan of the animal, rat liver undergoes three distinct phases of androgen sensitivity, i.e. prepubertal androgen insensitivity, androgen sensitivity after approximately 40 days of age, and androgen insensitivity during senescence (greater than 750 days). EST in the liver is expressed only after puberty, when the liver becomes androgen sensitive. Furthermore, localization of EST and its corresponding mRNA within the lobular unit of the liver demonstrates that only androgen-responsive hepatocytes located around the central vein contain immunoreactive EST and its corresponding mRNA. These temporal and spatial correlations of EST expression and hepatic androgen sensitivity support the concept that steroid-inactivating enzymes play important roles in sex hormone action.

Modification of metal-induced micronuclei formation in mouse bone marrow erythrocytes by Phyllanthus fruit extract and ascorbic acid

The comparative efficacy of Phyllanthus emblica fruit extract, and its main constituent, ascorbic acid, in modifying the cytotoxic action of lead and aluminium was evaluated in vivo in bone marrow cells of Mus musculus. Oral administration of Phyllanthus emblica fruit extract for 7 days before exposure to the metals through intraperitoneal injections reduced the frequency of micronuclei induced by all doses of both metals. Priming with comparable doses of synthetic ascorbic acid reduced micronuclei formation induced by both doses of aluminium and only the lower dose of lead. With the higher dose of lead (20 mg/kg body wt.) priming with ascorbic acid increased the frequency of micronuclei when compared with mice administered lead alone. The greater efficacy of Phyllanthus fruit extract in alleviating metal-induced clastogenicity may be due to the combined action of all ingredients in the crude extract, rather than to ascorbic acid alone.