Differential inhibition of rat hepatic glutathione S-transferase isoenzymes in the course of fascioliasis

The effects of a subclinical fascioliasis at various stages of its development (at week 3, 6 and 9 after infection by oral administration of 20 metacercariae of Fasciola hepatica) in rats were determined on the activity of enzymes involved in liver metabolism of glutathione and on the subunit pattern of cytosolic glutathione S-transferase. The parasitic pathology was ascertained by clinical observation of the rats and at autopsy. Hepatic microsomal cytochrome P-450 content was significantly decreased in infected rats by week 3 and 6 post-infection. Not correlatively, the catalytic activities of glutathione S-transferase towards 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene were significantly lowered in last stages of the experimental fascioliasis (by week 6 and 9 post-infection). These decreases were correlated to that of subunit 1 as determined by means of high-performance liquid chromatography of cytosolic proteins whereas subunit 6 could also be decreased. Fascioliasis did not alter cytosolic glutathione, glutathione reductase and glutathione peroxidase activities or plasma glutathione S-transferase activity accepting 1-chloro-2,4-dinitrobenzene as the substrate.     

Distribution of alpha glutathione S-transferase in ovarian neoplasms: an immunohistochemical study

AIMS: Alpha glutathione S-transferase (alpha-GST) has been shown to be an immunohistochemical marker for delta(4-5) isomerase, an enzyme active in steroidogenesis. The purpose of this study was to document the distribution of alpha-GST in ovarian neoplasms in order to evaluate its usefulness as a diagnostic tool. METHODS AND RESULTS: A total of 92 tumours (25 sex cord/stromal, 53 epithelial and 14 germ cell) were subjected to immunohistochemistry using a commercially available polyclonal antibody to alpha-GST. The avidin-biotin complex was used as a detection system. Positive staining was found in luteinized stromal cells of all tumour types (58/92). This included the Leydig cells of Sertoli-Leydig cell tumours (7/7) and was particularly prominent in the stromal cells of both benign and malignant mucinous tumours (24/25). Granulosa and Sertoli cells showed weak or no intracytoplasmic staining, which is expected because they do not normally produce androstenedione. They did show some intranuclear staining. Malignant mucinous (12/25) and occasional other epithelial tumours showed focal intracytoplasmic positive staining. Yolk sac tumours showed focal positivity (7/8). CONCLUSIONS: Intracytoplasmic staining of stromal cells is considered to indicate steroidogenesis and intranuclear staining the intracytoplasmic transport function of alpha-GST. The intracytoplasmic staining of mucinous carcinomas might represent an up-regulation of some detoxification function. The findings suggest that antibody to alpha-GST has some value in the investigation of ovarian pathology and could readily be included in any panel of antibodies used to investigate ovarian neoplasms of uncertain histogenesis.     

Electrophoretic and immunological analysis of human glutathione S-transferase isozymes

Several electrophoretically distinct glutathione S-transferase isozymes from different tissues have been purified and characterized. The data confirm the suggestion that GST-1, GST-2 and GST-3 are the products of separate genetic loci.
An apparently muscle-specific isozyme termed GST-4 has been identified and shown to differ structurally from GST-1, GST-2 and GST-3. It is likely that GST-4 is the product of an additional gene locus.
Two isozymes termed GST-5 and GST-6 were purified from brain. GST-5 has a different isoelectric point, but shares many structural features with GST-1. GST-5 may be a brain-specific post-translationally modified product of the GST-1 gene. GST-6 is an acidic isozyme found in many tissues. The data indicate that GST-6 is composed of two dissimilar subunits that do not cross-react with antiserum directed against GST-1, GST-2 or GST-3. These observations therefore suggest that GST-6 may have an independent genetic origin.     

Cell age dependent decay of human erythrocytes glutathione S-transferase

Human red blood cells contain both glutathione S-transferase sigma (GST sigma) and glutathione S-transferase rho (GST rho). While the first isozyme does not change in red blood cell fractions of different mean density (age), GST rho, the main isozyme, shows a pronounced cell age dependent decay. Ion-exchange chromatographic experiments show that GST rho consists of only one isozymic form in young erythrocytes but is present in two components, with different electric charge, in mature and old cells. The "secondary" GST rho isozyme is more heat stable than the "primary" GST rho isozyme with the result that the total GST activity shows an apparent increase in heat stability during cell aging due to the formation of "secondary" isozymes. The kinetic properties and specificity of this enzyme do not show appreciable modifications during cell ageing. The data reported in this paper suggest that red blood cell aging is associated with a reduced detoxifying ability due to GST rho decay.     

Heterogeneity of clara cell glutathione. A possible basis for differences in cellular responses to pulmonary cytotoxicants

Clara-cell populations show a high degree of variation in susceptibility to injury by bioactivated cytotoxicants. Because glutathione (GSH) is critical for detoxification of electrophilic metabolites, heterogeneity in Clara cell GSH levels may lead to a wide range of cytotoxic responses. This study was designed to define the distinct GSH pools within Clara cells, characterize heterogeneity within the population, and examine whether heterogeneity contributes to susceptibility. Using fluorescent imaging combined with high-performance liquid chromatography analysis, semiquantitative measurements were obtained by evaluation of GSH using monochlorobimane and monobromobimane. In steady-state conditions, the GSH measured in isolated cells was in the femtomole range, but varied 4-fold between individual cells. Clara cells analyzed in situ and in vitro confirmed this heterogeneity. The response of these cells to compounds that modulate GSH was also variable. Diethylmaleate depleted GSH, whereas GSH monoethylester augmented it. However, both acted nonuniformly in isolated Clara cells. The depletion of intracellular GSH caused a striking decrease in cell viability upon incubation with naphthalene (NA). The sulfhydryl-binding fluorochrome BODIPY, which colocalized with tetramethylrosamine, a mitochondrial dye, demonstrated by confocal microscopy that cellular sulfhydryls are highest in the mitochondria, next-highest in cytoplasm, and lowest in the nucleus. These pools responded differently to modulators of GSH. We concluded that the steady-state intracellular GSH of Clara cells exists in distinct pools and is highly heterogeneous within the population, and that the heterogeneity of GSH levels corresponds closely to the response of Clara cells to injury by NA.     

A novel type of glutathione S-transferase in Onchocerca volvulus.

Onchocerca volvulus is a pathogenic human filarial parasite which, like other helminth parasites, is capable of evading the host's immune responses by a variety of defense mechanisms which are likely to include the detoxification and repair mechanisms of the enzyme glutathione S-transferase (GST). In this study, we show that one of the previously described GSTs from O. volvulus appears to possess the characteristics of a secreted enzyme. When the complete O. volvulus GST1 (OvGST1) sequence presented here is compared with those of other GSTs, 50 additional residues at the N terminus are observed, the first 25 showing characteristics of a signal peptide. This is consistent with the N-terminal sequence data on the native mature enzyme which begins at amino acid 26, based on the deduced protein sequence from the cDNA. The native protein, without the signal peptide sequence, possesses a 24-amino-acid extension not present in other GSTs. The deduced amino acid sequence of the OvGST1 cDNA clone was shown to possess four potential N-glycosylation sites. Digestion of O. volvulus homogenate with endoglycosidase, followed by detection of OvGST1 with specific antibody, indicated that the enzyme possesses at least two N-linked oligosaccharide chains. Gel filtration of the Escherichia coli-produced recombinant OvGST1 showed that it is enzymatically active as a nonglycosylated dimer. OvGST1 is found in the media surrounding adult worms maintained in culture, indicating that, in vitro, this enzyme is released from the worm. The strongest immunostaining for OvGST1 was observed in the outer cellular covering of the adult worm body, the syncytial hypodermis, especially in the interchordal hypodermis, where the peripheral membrane forms a series of lamellae which run into the outer zone of the hypodermal cytoplasm.     

Cloning, expression and characterization of human glutathione S-transferase Omega 2

The class of Omega glutathione transferases is newly identified with novel structural and functional characteristics. Human GSTO 1-1 (glutathione S-transferase Omega 1) is the first member of the GST Omega class. It was found to play a role in apoptosis and be in association with age-at-onset of AD and PD. In order to improve the understanding of the properties of other Omega class members, we screened a human fetal brain cDNA library and obtained the human GSTO2 (glutathione S-transferase Omega 2) cDNA. The full-length cDNA of human GSTO2 is 1179 bp long and encodes a protein of 243 amino acid residues. Expression pattern analysis revealed that GSTO2 was ubiquitously expressed at a low level, with a higher expression in pancreas and prostate. Enzyme assays showed that GSTO2 protein had activities similar to Omega class GSTs. It has detectable glutathione-dependent thiol transferase activity and glutathione-dependent dehydroascorbate reductase activity. But different from GSTO1-1, GSTO2 exhibits a high catalytic activity with CDNB. Subcellular localization analysis of GSTO2-EGFP fusion protein revealed that GSTO2 distributed to cytoplasm of COS-7 cells and both cytoplasm and nucleus of L-02, QGY-7703 and SMMC-7721 cells. Overexpression of GSTO2 induced apoptosis of L-02 cells detected by Annexin V-PE staining. The results suggest that GSTO2 may play an important role in cellular signaling.     

An immunohistochemical study of pi class glutathione S-transferase expression in normal human tissue

Glutathione S-transferases (GSTs), a family of isoenzymes that play an important role in protecting cells from cytotoxic and carcinogenic agents, can be separated by biochemical and immunologic characteristics into three distinct classes named alpha, mu, and pi. Previous studies have indicated that there is marked heterogeneity in the expression of different GST isoenzymes in different normal and malignant tissues. To better understand the regulation of the human pi class glutathione S-transferase isoenzyme (GST-pi), the tissue distribution of this protein wa studied by an immunohistochemical technique using an anti-GST-pi polyclonal antibody in normal paraffin-embedded human tissues. These studies indicate that there is a broad distribution of GST-pi in normal human tissues and establish a precise localization within the different organs studied. GST-pi was expressed predominantly in normal epithelial cells of the urinary, digestive, and respiratory tracts, suggesting a possible role for GST-pi in detoxication and elimination of toxic substances. Previous studies have indicated that GST-pi and the putative drug efflux pump P-glycoprotein are both overexpressed in multidrug-resistant human breast cancer cells and in xenobiotic resistant preneoplastic rat hyperplastic liver nodules. Results from this study indicate that there are also similarities between the normal tissue distribution GST-pi and that previously reported for mammalian P-glycoprotein, particularly in secretory epithelia. This finding suggests that these two gene products, which have been implicated in the development of resistance to cytotoxic drugs, may be coregulated in normal and malignant cells.     

Tubular kidney injury molecule-1 (KIM-1) in human renal disease

KIM‐1, a transmembrane tubular protein with unknown function, is undetectable in normal kidneys, but is markedly induced in experimental renal injury. The KIM‐1 ectodomain is cleaved, detectable in urine, and reflects renal damage. KIM‐1 expression in human renal biopsies and its correlation with urinary KIM‐1 (uKIM‐1) is unknown. In biopsies from various renal diseases (n = 102) and controls (n = 7), the fraction of KIM‐1 positive tubules and different renal damage parameters were scored. Double labelling was performed for KIM‐1 with macrophages (MØ), α‐smooth muscle actin (α‐SMA), proximal (aquaporin‐1) and distal (E‐cadherin) tubular markers and a dedifferentiation marker (vimentin). uKIM‐1 at the time of biopsy (n = 53) was measured by ELISA. Renal KIM‐1 was significantly increased in all diseases versus controls (p < 0.05), except minimal change. KIM‐1 was primarily expressed at the luminal side of dedifferentiated proximal tubules, in areas with fibrosis (α‐SMA) and inflammation (MØ). Independent of the disease, renal KIM‐1 correlated positively with renal damage, negatively with renal function, but not with proteinuria. uKIM‐1 was increased in renal patients versus controls (p < 0.001), including minimal change, and correlated positively with tissue KIM‐1 and MØ, negatively with renal function, but not with proteinuria. In conclusion, KIM‐1 is upregulated in renal disease and is associated with renal fibrosis and inflammation. uKIM‐1 is also associated with inflammation and renal function, and reflects tissue KIM‐1, indicating that it can be used as a non‐invasive biomarker in renal disease. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

gamma-Glutamyl transferase isoenzymes in human bile.

The gamma-glutamyl transferase isoenzymes of bile were studied using electrophoretic, gel filtration, and ultracentrifugation techniques. In view of the known association of other biliary enzymes with lipids the effects of butanol extraction were investigated. The results show the presence of four isoenzymes of gamma-glutamyl transferase in bile, differing in electrophoretic mobilities, molecular size, and density. The correlation between the properties of biliary gamma-glutamyl transferase and of alkaline phosphatase is discussed.     

Interference in SV40 DNA infections: a possible basis for cellular competence.

At the restrictive temperature, DNA from temperature-sensitive mutants of simian virus 40 (SV40) (in the A or B/C genes) interferes with plaque formation by wild-type SV40 DNA. This interference occurs early in the first cycle of infection. Nonhomologous DNA also can interfere with SV40 DNA infection. The mode of interference by ts SV40 DNAs and nonhomologous DNAs appears to be the same. In conjunction with other observations the interference by nonhomologous DNA and the similarity of interference by tsA DNA and tsB DNA suggest that interference does not require expression of any viral gene product. Since interference is observed even when the infections by interfering DNA and wild-type DNA are separated in time, interference must occur after the DNAs interact with cells. Furthermore, the different efficiencies with which structurally similar DNAs (SV40, PM2 and φX174 replicative form) interfere indicate that interference depends at least in part on nucleotide sequence. Those two observations suggest that interference is an intracellular, perhaps nuclear, phenomenon. The possible relevance of this interference phenomenon to observations on cellular competence for SV40 DNA infections is discussed.     

乳腺癌中胎盘型谷胱甘肽S－转移酶基因的扩增与异常表达

在国内首次制备并用光敏生物素方法标记胎盘型谷胱甘肽Ｓ－转移酶（ＧＳＴ－π）ｃＤＮＡ探针，应用斑点杂交技术检测２４例乳腺癌ＧＳＴ－π基因ＤＮＡ扩增与ｍＲＮＡ异常表达。结果发现，２４例乳腺癌中，３例（１２．５％）存在ＤＮＡ扩增，７例（２９．２％）存在ｍＲＮＡ异常表达，ＤＮＡ扩增和ｍＲＮＡ表达之间存在正相关性，二者均与患者年龄、肿瘤大小、淋巴结转移无明显相关，但ｍＲＮＡ异常表达与乳腺癌ＥＲ表达呈现负相关性。结果证实人乳腺癌中既存在ＧＳＴ－π基因ＤＮＡ扩增，又存在ｍＲＮＡ异常表达，提示ＧＳＴ－π与乳腺癌有密切关系。     

广东地区汉族人群的hGSTP1Ile105Val基因多态性的研究

目的:对广东地区汉族人群的hGSTP1Ile105Val基因多态性进行研究。方法:应用PCR-RFLP(基因体外扩增限制性片段长度多态性分析)的技术方法进行研究。结果:该人群中GSTP1基因在105位点的野生型纯合子(AA)基因型的分布频率为57.4%,突变型纯合子(GG)基因型为6.7%,杂合子(AG)基因型为35.9%。结论:GSTP1纯合突变基因型在广东地区汉族人群中的分布频率为6.7%。     

Chemical inhibition method for alkaline phosphatase isoenzymes in human serum.

The authors adapted a chemical inhibition procedure using L-phenylalanine and urea as specific inhibitors to quantitate the activities of bone, liver, and intestinal alkaline phosphatase (ALP) isoenzymes in human serum. The results of this assay were compared with electrophoretic separation, gamma-glutamyl transpeptidase (GGTP) activity, and the clinical setting in a group of patients with elevated total ALP activity. In addition, expected ranges of serum ALP isoenzymes for healthy young men and also for a geriatric population are presented.     

Localized in vivo proton spectroscopy of renal cell carcinoma in human kidney.

In order to obtain proton magnetic resonance spectra from the renal tumor in human kidney we performed localized magnetic resonance spectroscopy using a saddle-type flexible surface coil. Five patients biopsy-proven as renal cell carcinoma at different stages were put in supine/lateral position to minimize motion artifacts while acquiring the spectrum. Water-suppressed 1H spectra were obtained with localized stimulated echo acquisition mode (STEAM) (20/13.7/2200; TE/TM/TR) and point resolved spectroscopy (PRESS) (288/2200; TE/TR) sequences. The principal resonances in the tumor STEAM spectrum were sorbitol (3.85 ppm), trimethylamines (TMA) (3.25 ppm), two unidentified signals (2.8 and 2.2 ppm), and lipid (0.9-1.8 ppm). In the PRESS spectrum using a long echo time (288 ms), two well localized signals, TMA at 3.25 ppm and lactate at 1.35 ppm were observed from a patient with a tumor at advanced stage. Interestingly only TMA at 3.25 ppm was observed from the patient with a low grade tumor. The spectral patterns of the tumor patients were different from those of normal kidney.     

Multiple variations of the renal and testicular vessels: possible embryological basis and clinical importance

During routine dissection of the abdominal cavity of a 55-year-old African male cadaver, multiple anomalies including renal and testicular vessels were encountered. The right kidney was supplied by three right hilar renal arteries arising from the abdominal aorta at different vertebral levels whereas only one left renal artery supplied the left kidney. On the right three renal veins drained the kidney into the inferior vena cava. In contrast, the left kidney was drained by a single renal vein which received a large primary posterior tributary. The primary posterior tributary had three tributaries from the posterior lumbar region. The right testis had two sources of arterial supply; one from the subcostal artery and another from the abdominal aorta. The left testis was supplied normally by a single testicular artery. The right testis was drained by four testicular veins as follows: one drained into the subcostal vein, the other two drained separately for a longer course and joined shortly before draining into the right main renal vein, the fourth one drained into the anterior aspect of the inferior vena cava at the level of the second lumbar vertebra. On the left, the testicle was drained by two testicular veins which travelled separately from the deep inguinal ring and joined shortly before they drain into the left renal vein. This variation may represent an immature form of complicated development of kidneys and testes. Additionally, emphasis must be put on preoperative vascular examination to avoid surgical complications from variant vessels in this region.     

Physiological basis for absorptive and renal hypercalciurias.

Idiopathic hypercalciuria constitutes two major variants-absorptive hypercalciuria, characterized by a primary intestinal hyperabsorption of calcium, and renal hypercalciuria, in which renal tubular reabsorption of calcium is primarily impaired. The two forms of hypercalciuria may be distinguished from each other, since a) parathyroid function is stimualted in renal hypercalciuria, but normal or suppressed in absorptive hypercalciuria, b) the renal leak of calcium is present in renal hypercalciuria, but not in absorptive hypercalciuria, c) intestinal calcium absorption is probably increased primarily in absorptive hypercalciuria, and secondarily in renal hypercalciuria (from parathyroid hormone excess), d) the increased calcium absorption in renal hypercalciuria probably results from the parathyroid hormone-dependent stimulation of 1,25-dihydroxyvitamin D synthesis, whereas that in absorptive hypercalciuria may be vitamin D-independent, e) the response of the two conditions to certain treatments is unique, and f) the sequelae of parathyroid hormone excess, such as low bone density and negative calcium balance, may be present in renal hypercalciuria, but not in absorptive hypercalciuria. These findings provide a physiological basis for the consideration of absorptive and renal hypercalciurias as distinct and separate entities.