Biomedical subjects

M A Rubin

Publications and source records attributed to M A Rubin.

At least 19 recordsLinked to original sources

PubMed2006

A pyrazolyl-thiazole derivative causes antinociception in mice.

The present study investigates the antinociceptive effect of the pyrazolyl-thiazole derivative 2-(5-trichloromethyl-5-hydroxy-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl)-4-(4-bromophenyl)-5-methylthiazole (B50) in mice. Male albino Swiss mice (30-40 g) were used in the acetic acid-induced abdominal writhes and tail-immersion tests. B50 caused dose-dependent antinociception (8, 23 and 80 micromol/kg, s.c.) in the acetic acid writhing assay (number of writhes: vehicle: 27.69 +/- 6.15; B50 (8 micromol/kg): 16.92 +/- 3.84; B50 (23 micromol/kg): 13.85 +/- 3.84; B50 (80 micromol/kg): 9.54 +/- 3.08; data are reported as means +/- SEM for 9 animals per group). On the other hand, B50 did not cause antinociception in the tail immersion assay. Naloxone (2.75 micromol/kg, s.c.) prevented B50-induced antinociception (number of writhes: vehicle-saline: 31.11 +/- 3.15; vehicle-naloxone: 27.41 +/- 3.70; B50 (80 micromol/kg)-saline: 8.70 +/- 3.33; B50 (80 micromol/kg)-naloxone: 31.84 +/- 4.26; morphine-saline: 2.04 +/- 3.52; morphine-naloxone: 21.11 +/- 4.26; 8-9 animals per group). The removal of the methyl group of the thiazole ring of B50 or substitution of the bromo substituent with the methyl at position 4 of the phenyl group, which is attached to the thiazole ring of B50, resulted in loss of activity, suggesting that these substituents are important for antinociceptive activity. B50 had no effect on spontaneous locomotion or rotarod performance, indicating that the antinociceptive effect of B50 is not related to nonspecific motor effects. The antinociceptive profile of B50 seems to be closer to nonsteroidal anti-inflammatory drugs than to classic opioid agents, since it had no analgesic effect in a thermally motivated test.

Acetic Acid↗

PubMed2006

[Cytogenetic alterations in renal tumors. Applications for comparative genomic hybridization and fluorescence in situ hybridization].

The WHO classification of renal cell carcinomas (RCC) takes into account chromosomal alterations. New cytogenetic techniques such as comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH) offer alternative methods to the classic cytogenetic banding technique. Clear cell (classic) RCC frequently show the loss of 3p. Papillary RCC are characterized by trisomies and tetrasomies as well as loss of the Y chromosome. CGH analysis demonstrates that DNA copy increase is more common in type I papillary RCC compared to type II. Chromophobe RCC are characterized by losses in chromosomes 1, 2, 6, 10, 13, 17, and 21. Oncocytomas can be divided into cases with rearrangements in the 11q13 region and those with loss of chromosome 1 and the sex chromosomes. Translocations involving chromosome 3, such as t(3;8)(p14;q24.13) and t(2;3)(q35;q21) have been described in familial clear cell RCC. The most recent class of RCC, seen only in men, is referred to as translocation tumors. These tumors demonstrate a tubulopapillary growth pattern and have a t(X;1)(p11.2;q21.2) translocation. Although not required for most clinical diagnoses, CGH and FISH complement the standard histologic diagnosis of RCC and may provide a definitive diagnosis in a small number of challenging cases.

Carcinoma, Renal Cell↗

PubMed2005

Succinate causes oxidative damage through N-methyl-D-aspartate-mediated mechanisms.

In this study we investigated whether succinate, the accumulating substrate in succinate dehydrogenase (SDH) deficiencies and SDH inhibitor intoxication, causes lipoperoxidation and protein carbonylation, and if NMDA receptors are involved in the succinate-induced oxidative damage. Adult male mice (30-40 g) received an intracerebroventricular injection of succinic acid (0.7, 1.0 and 1.7 micromol/5 microl) or 0.9% NaCl (5 microl) and had their exploratory behavior assessed in an open field for 10 min. Succinate (0.7 and 1.0 micromol/5 microl) decreased locomotor activity behavior and increased thiobarbituric acid reactive substances (TBARS) and protein carbonylation in the forebrain. Conversely, 1.7 micromol of succinate did not alter locomotor activity or oxidative damage parameters. The involvement of NMDA receptors in the succinate-induced increase of total protein carbonylation content and exploratory behavior inhibition was assessed by co-administrating MK-801 (7 nmol/2.5 microl icv), a noncompetitive NMDA receptor antagonist, with succinate (1 micromol/2.5 microl icv). The co-administration of MK-801 protected against succinate-induced increase of total protein carbonylation and decrease of locomotor activity. These results suggest the involvement of NMDA receptors in these effects of succinate, which may of particular relevance for succinate-accumulating conditions, such as SDH inhibitors intoxication and inherited SDH deficiencies.

Animals↗

PubMed2005

Assessment of a fragment of e-cadherin as a serum biomarker with predictive value for prostate cancer.

In prostate cancer, biomarkers may provide additional value above standard clinical and pathology parameters to predict outcome after specific therapy. The purpose of this study is to evaluate an 80 kDa fragment of the cell adhesion molecule e-cadherin as a serum biomarker. A broad spectrum of prostate cancer serum samples, representing different stages of prostate cancer disease, including benign prostatic hyperplasia (BPH), localised (Loc PCA) and metastatic prostate cancer (Met PCA), was examined for the cleaved product. There is a significant difference in the expression level of the 80 kDa fragment in the serum of healthy individuals vs patients with BPH and between BPH vs Loc PCA and Met PCA (P<0.001). Highest expression levels are observed in advanced metastatic disease. In the cohort of Loc PCA cases, there was no association between the 80 kDa serum concentration and clinical parameters. Interestingly, patients with an 80 kDa level of >7.9 microg l(-1) at the time of diagnosis have a 55-fold higher risk of biochemical failure after surgery compared to those with lower levels. This is the first report of the application of an 80 kDa fragment of e-cadherin as a serum biomarker in a broad spectrum of prostate cancer cases. At an optimised cutoff, high expression at the time of diagnosis is associated with a significantly increased risk of biochemical failure, potentially supporting its use for a tailored follow-up protocol for those patients.

Aged↗

PubMed2005

"Lineage addiction" in human cancer: lessons from integrated genomics.

Genome-era advances in the field of oncology endorse the notion that many tumors may prove vulnerable to targeted therapeutic avenues once their salient molecular alterations are elucidated. Accomplishing this requires both detailed genomic characterization and the ability to identify in situ the critical dependencies operant within individual tumors. To this end, DNA microarray platforms such as high-density single-nucleotide polymorphism (SNP) arrays enable large-scale cancer genome characterization, including copy number and loss-of-heterozygosity analyses at high resolution. Clustering analyses of SNP array data from a large collection of tumor samples and cell lines suggest that certain copy number alterations correlate strongly with the tissue of origin. Such lineage-restricted alterations may harbor novel cancer genes directing genesis or progression of tumors from distinct tissue types. We have explored this notion through combined analysis of genome-scale data sets from the NCI60 cancer cell line collection. Here, several melanoma cell lines clustered on the basis of increased dosage at a region of chromosome 3p containing the master melanocyte regulator MITF. Combined analysis of gene expression data and additional functional studies established MITF as an amplified oncogene in melanoma. MITF may therefore represent a nodal point within a critical lineage survival pathway operant in a subset of melanomas. These findings suggest that, like oncogene addiction, "lineage addiction" may represent a fundamental tumor survival mechanism with important therapeutic implications.

Chromosomes, Human, Pair 3↗

PubMed2004

Antinociceptive effect of novel pyrazolines in mice.

The antinociceptive effect of six novel synthetic pyrazolines (3-ethoxymethyl-5-ethoxycarbonyl-1H-pyrazole (Pz 1) and its corresponding 1-substituted methyl (Pz 2) and phenyl (Pz 3) analogues, and 3-(1-ethoxyethyl)-5-ethoxycarbonyl-1H-pyrazole (Pz 4) and its corresponding 1-substituted methyl (Pz 5) and phenyl (Pz 6) analogues) was evaluated by the tail immersion test in adult male albino mice. The animals (N = 11-12 in each group) received vehicle (5% Tween 80, 10 ml/kg, sc) or 1.5 mmol/kg of each of the pyrazolines (Pz 1-Pz 6), sc. Fifteen, thirty and sixty minutes after drug administration, the mice were subjected to the tail immersion test. Thirty minutes after drug administration Pz 2 and Pz 3 increased tail withdrawal latency (vehicle = 3.4 +/- 0.2; Pz 2 = 5.2 +/- 0.4; Pz 3 = 5.9 +/- 0.4 s; mean +/- SEM), whereas the other pyrazolines did not present antinociceptive activity. Dose-effect curves (0.15 to 1.5 mmol/kg) were constructed for the bioactive pyrazolines. Pz 2 (1.5 mmol/kg, sc) impaired motor coordination in the rotarod and increased immobility in the open-field test. Pz 3 did not alter rotarod performance and spontaneous locomotion, but increased immobility in the open field at the dose of 1.5 mmol/kg. The involvement of opioid mechanisms in the pyrazoline-induced antinociception was investigated by pretreating the animals with naloxone (2.75 micro mol/kg, sc). Naloxone prevented Pz 3- but not Pz 2-induced antinociception. Moreover, naloxone pretreatment did not alter Pz 3-induced immobility. We conclude that Pz 3-induced antinociception involves opioid mechanisms but this is not the case for Pz 2.

Analgesics↗

PubMed2004

[Tissue microarrays. High-throughput procedures to verify potential biomarkers].

High-throughput molecular screening tools have created a need for equally rapid means to verify potential biomarkers. Tissue microarray (TMA) technology facilitates effective analysis on the protein level. Hundreds of 0.6-mm-diameter tissue samples are placed on a single standard glass slide. This approach allows analysis with different in situ methods of all tissue samples in one experiment under standardized conditions. TMAs are not only perfectly suited for molecular epidemiologic studies if applied on multitumor arrays composed of a variety of tumor entities, but they are also used for tumor-specific investigations of molecular markers. In this report the technical aspects of TMAs as a miniaturized high-throughput technology are described. We further demonstrate how the TMA technique will help to accelerate the transition from basic research to clinical application in prostate cancer disease.

Biomarkers, Tumor↗

PubMed2004

Succinate increases neuronal post-synaptic excitatory potentials in vitro and induces convulsive behavior through N-methyl-d-aspartate-mediated mechanisms.

Succinate is a dicarboxylic acid that accumulates due to succinate dehydrogenase inhibition by malonate and methylmalonate exposure. These neurotoxins cause increased excitability and excitotoxic damage, which can be prevented by administering high amounts of succinate. In the present study we investigated whether succinate alters hippocampal field excitatory post-synaptic potentials. Bath application of succinate at intermediate concentrations (0.3-1 mM) increased the slope of field excitatory post-synaptic potentials in hippocampal slices, and at high concentrations (above 1 mM) did not alter or decrease field excitatory post-synaptic potentials slope. Succinate-induced enhancement of field excitatory post-synaptic potentials slope was abolished by the addition of d-2-amino-5-phosphonovaleric acid (50 microM) to the perfusate, supporting the involvement of N-methyl-d-aspartate receptors in the excitatory effect of this organic acid. Accordingly, succinate (0.8-7.5 micromol) i.c.v. administration caused dose-dependent convulsive behavior in mice. The i.c.v. co-administration of MK-801 (7 nmol) fully prevented succinate-induced convulsions, further suggesting the involvement of N-methyl-d-aspartate receptors in the convulsant action of succinate. Our data indicate that accumulation of moderate amounts of succinate may contribute to the excitotoxicity induced by succinate dehydrogenase inhibitors, through the activation of N-methyl-d-aspartate receptors.

Animals↗

PubMed2004

Intrastriatal malonate administration induces convulsive behaviour in rats.

Malonic acidaemia is an inborn error of metabolism that accumulates malonate, a competitive succinate dehydrogenase (SDH; EC 1.3.99.1) inhibitor. The present study investigated the behavioural effects of unilateral intrastriatal administration of malonate (0.6, 1.8 or 6 micromol) in adult male Wistar rats (n=10-13). Low doses of malonate (1.8 micromol) decreased exploratory activity and caused ipsiversive rotational behaviour. High doses of malonate (6 micromol) induced contralateral rotational behaviour and convulsive episodes. Malonate competitively inhibited SDH in mitochondrion-enriched fractions from striatum ( Ki=0.034+/-0.008 mmol/L). Interestingly, methylmalonate, which is a weaker SDH inhibitor than malonate (Ki=4.22+/-1.3 mmol/L), induced more convulsions than malonate at equimolar doses and did not cause ipsiversive rotational behaviour. It is suggested that the potency of SDH inhibition in vitro does not correlate positively with the convulsant potential of these inhibitors in vivo.

Acute Disease↗

PubMed2004

Comparison of external radiation therapy vs radical prostatectomy in lymph node positive prostate cancer patients.

INTRODUCTION: Treatment options for lymph node positive prostate cancer are limited. We retrospectively compared patients who underwent external radiotherapy (ERT) to patients treated by radical prostatectomy (RPX). MATERIALS AND METHODS: A total of 102 lymph node positive patients from the RPX series at Ulm University were evaluated. In all, 76 patients received adjuvant androgen withdrawal as part of their primary treatment. In the ERT group, 44 patients were treated at the University of Michigan using a fractionated regimen. Of these, 21 patients received early adjuvant hormonal therapy. Patients with neoadjuvant therapy before RPX or ERT were excluded. RESULTS: In the RPX group, PSA nadir (nadir < or = 0.2 vs > 0.2 ng/ml) showed a strong association with outcome. In the ERT group, pretreatment PSA was an independent predictor of outcome (P = 0.04) and patients with adjuvant hormonal therapy had a significant longer recurrence-free interval compared to patients without adjuvant therapy (P = 0.004). Comparing only patients with adjuvant hormonal treatment after cancer-specific therapy, the ERT-treated patients had a borderline longer PSA recurrence-free survival time compared to the RPX-treated patients (P = 0.05). CONCLUSIONS: In case of positive lymph nodes, RPX and ERT might be considered and need to be explained to the patient. For future treatment decisions, the presented findings and a potential survival benefit need to be evaluated in a larger prospective setting.

Aged↗

PubMed2002

Antinociceptive effects of Cremophor EL orally administered to mice.

Surfactants are frequently used to improve solubilization of lipophilic drugs. Cremophor EL (CrEL) is a polyoxyethylated castor oil surfactant used to solubilize water-insoluble drugs such as anesthetic, antineoplastic, immunosuppressive and analgesic drugs, vitamins and new synthetic compounds, including potential analgesics. The antinociceptive effect of CrEL (3.2, 6.4 and 10.6 g/kg, in 10 ml/kg body weight, by gavage) on the abdominal writhing response induced by intraperitoneal administration of acetic acid (0.8%, 10 ml/kg body weight) and on the tail immersion test was investigated in mice. Control animals received castor oil (10 ml/kg body weight) or saline (0.9% NaCl, 10 ml/kg body weight). CrEL reduced nociception in a dose-dependent manner in both tests. At 10.6 g/kg, CrEL caused antinociception similar to that induced by dipyrone (300 mg/kg, by gavage) in the abdominal writhing test, and antinociception similar to that induced by morphine (20 mg/kg, by gavage) in the tail immersion test. The effect of castor oil was similar to that of saline in both assays. These data indicate that the appropriate controls should be used when evaluating the effects of potential antinociceptive agents dissolved in CrEL.

Administration, Oral↗

PubMed2002

Antioxidant properties of new chalcogenides against lipid peroxidation in rat brain.

Ebselen (2-phenyl- 1,2-benzisoselenazole-3 (2H)-one) is a seleno-organic compound with antioxidant properties, and anti-inflammatory actions. Recently, ebselen improved the outcome of acute ischemic stroke in humans. In the present study, the potential antioxidant capacity of organochalcogenide compounds diphenyl diselenide (PhSe)2, diphenyl ditelluride (PhTe)2, diphenyl disulfide (PhS)2, p-Cl-diphenyl diselenide (pCl-PhSe)2, bis-[S-4-isopropyl 2-phenyl oxazoline] diselenide (AA-Se)2, bis-[S-4-isopropyl 2-phenyl oxazoline] ditelluride (AA-Te)2 and bis-[S-4-isopropyl 2-phenyl oxazoline] disulfide (AA-S)2 was compared with that of ebselen (a classical antioxidant). Spontaneous and quinolinic acid (QA)- (2 mM) and sodium nitroprusside (SNP)- (5 microM)-induced thiobarbituric reactive species (TBARS) production by rat brain homogenates was determined colorimetrically. TBARS formation was reduced by ebselen, (PhSe)2, (PhTe)2, (AA-Se)2, (AA-S)2 and (pCl- PhSe)2 to basal rates. The concentrations of these compounds needed to inhibit TBARS formation by 50% (IC50) are 1.71 microM, 3.73 microM, 1.63 microM, 9.85 microM, >33.3 microM, 23.2 microM and 4.83 microM, respectively for QA. For TBARS production induced by SNP the IC50 was 2.02 microM, 12.5 microM, 2.80 microM, >33.3 microM, 24.5 microM and 7.55 microM, respectively. The compounds (AA-Te)2 and (PhS)2 have no antioxidant activity and pro-oxidant activity, respectively. These results suggest that (AA-Se)2 and (AA-S)2 can be considered as potential pharmaceutical antioxidant agents.

Animals↗

PubMed2001

Loss of heterozygosity of the putative prostate cancer susceptibility gene HPC2/ELAC2 is uncommon in sporadic and familial prostate cancer.

The recognition that prostate cancer clusters within families has led to the search for prostate cancer susceptibility genes. Recently, the HPC2/ELAC2 gene on chromosome 17p has been identified as a potential prostate cancer predisposition gene using both family based as well as case-control studies. Many cancer susceptibility genes act as tumor suppressor genes in which inactivation of one allele in the tumor can be detected via loss of heterozygosity (LOH). To determine whether the HPC2/ELAC2 gene demonstrates significant LOH in sporadic and familial prostate cancers, paired tumor and normal DNA samples were isolated using microdissection techniques from 44 radical prostatectomy specimens. Cases were analyzed using a panel of markers in the following order: TP53-D17S969-D17S947-(HPC2/ELAC2)-D17S799-D17S936. LOH was observed in < 10% of cases using the four markers that map to the HPC2/ELAC2 region. However, allelic loss was observed at the TP53 gene in 25% of informative cases. Taken together, inactivation of the HPC2/ELAC2 gene via LOH is a relatively uncommon event in prostate cancer. Future studies will determine whether 17p LOH occurs in the subset of patients with an inherited mutation in HPC2/ELAC2.

Adult↗

PubMed2001

Delineation of prognostic biomarkers in prostate cancer.

Prostate cancer is the most frequently diagnosed cancer in American men. Screening for prostate-specific antigen (PSA) has led to earlier detection of prostate cancer, but elevated serum PSA levels may be present in non-malignant conditions such as benign prostatic hyperlasia (BPH). Characterization of gene-expression profiles that molecularly distinguish prostatic neoplasms may identify genes involved in prostate carcinogenesis, elucidate clinical biomarkers, and lead to an improved classification of prostate cancer. Using microarrays of complementary DNA, we examined gene-expression profiles of more than 50 normal and neoplastic prostate specimens and three common prostate-cancer cell lines. Signature expression profiles of normal adjacent prostate (NAP), BPH, localized prostate cancer, and metastatic, hormone-refractory prostate cancer were determined. Here we establish many associations between genes and prostate cancer. We assessed two of these genes-hepsin, a transmembrane serine protease, and pim-1, a serine/threonine kinase-at the protein level using tissue microarrays consisting of over 700 clinically stratified prostate-cancer specimens. Expression of hepsin and pim-1 proteins was significantly correlated with measures of clinical outcome. Thus, the integration of cDNA microarray, high-density tissue microarray, and linked clinical and pathology data is a powerful approach to molecular profiling of human cancer.

Biomarkers, Tumor↗

PubMed2001

Intra-amygdala spermidine administration improves inhibitory avoidance performance in rats.

In the present study, we investigated the effect of immediate post-training bilateral infusion of spermidine, a polyamine agonist, into the amygdala on inhibitory avoidance learning of rats. Bilateral microinjection of spermidine (0.02--20 nmol) caused an increase in test step-down latencies at high concentrations. Administration of arcaine (0.002--0.2 nmol), an antagonist of the NMDA receptor polyamine binding site, decreased test step-down latencies. On the other hand, co-administration of arcaine and spermidine completely reversed the spermidine-induced increase of test step-down latencies. These results provide evidence that polyamines may be involved in learning and memory modulation in the amygdala.

Amygdala↗

PubMed2001

Mitogen-activated protein kinase kinase 4 metastasis suppressor gene expression is inversely related to histological pattern in advancing human prostatic cancers.

We have shown recently (B. A. Yoshida et al., Cancer Res., 59: 5483-5487) that mitogen-activated protein kinase kinase 4 (MKK4) can suppress AT6.1 rat prostate cancer metastases in vivo. Evaluation of the expression of components of the MKK4 signaling cascade showed a loss or down-regulation of expression of MKK4 or c-Jun, a downstream mediator of MKK4, in six of eight human prostate cancer cell lines. Given these findings, we next assessed whether MKK4 dysregulation occurs during the development of clinical prostate cancer. Immunohistochemical studies showed high levels of MKK4 expression in the epithelial but not the stromal compartment of normal prostatic tissues. In neoplastic tissues, a statistically significant, direct, inverse relationship between Gleason pattern and MKK4 was established. These results demonstrate that MKK4 protein is consistently down-regulated during prostate cancer progression and support a role for dysregulation of its signaling cascade in clinical disease. To test the possibility that down-regulation of MKK4 protein is the result of allelic loss, metastatic prostate cancer lesions were examined for loss of heterozygosity (LOH) within the MKK4 locus (D17S969). These studies showed a 31% (5 of 16) LOH of MKK4 that is not associated with coding region mutations, which suggests that the nucleotide sequence of the gene in the remaining allele is infrequently mutated.

Enzyme Activation↗

PubMed2001

Activated in prostate cancer: a PDZ domain-containing protein highly expressed in human primary prostate tumors.

Critical events in prostate tumorigenesis and metastasis likely include the abnormal activation and expression of specific genes. Using RNA expression profiling techniques, we have identified a transcript originating from the activated in prostate cancer (AIPC) gene, the expression of which is preferentially up-regulated in several cultured prostate tumor cell lines and human primary prostate tumors. Sequence analysis revealed that the AIPC protein encodes six PDZ domains, which are protein-protein binding domains likely involved in protein clustering and scaffolding. Immunohistochemical analysis of a tissue microarray comprising 158 tumor, 18 high-grade prostatic intraepithelial neoplasia, and 91 normal prostate specimens with an anti-AIPC antibody demonstrated abundant AIPC protein expression in 75% of tumors, 83% of prostatic intraepithelial neoplasia lesions, and 3% of normal tissues (P < 0.0001). These data suggest that the accumulation of AIPC protein may be closely associated with the initiation or early promotion of prostate tumorigenesis.

Adaptor Proteins, Signal Transducing↗

PubMed2001

Posttranslational truncation and inactivation of human E-cadherin distinguishes prostate cancer from matched normal prostate.

An essential event in the progression of adenocarcinoma is the loss of organized epithelial attachment (both to the basement membrane and to adjoining epithelial cells). The E-cadherin cell adhesion molecule has an established function in maintaining normal phenotype and tissue homeostasis, and loss of E-cadherin function has been implicated in tumorigenesis. Aberrations in E-cadherin are associated with prostate cancer progression; however, these aberrations are not simply a result of prodigious allelic loss. We have previously demonstrated a novel posttranslational truncation within the cytosolic domain of native Mr 120,000 E-cadherin to a membrane-bound Mr 97,000 species. We hypothesize that truncation of E-cadherin is an inactivating event that is significantly increased in localized prostate tumors and that it represents a novel molecular event that may distinguish prostate cancer from adjacent normal tissue. E-cadherin was characterized by Western blot analysis in matched normal and cancer tissue from 18 prostate cancer patients. Imaging and densitometry software were used to quantify the truncation of E-cadherin by measuring the ratio of Mr 97,000 E-cadherin to Mr 120,000 E-cadherin, which was significantly increased in the tumor aspect of the prostate gland. Herein, we report the first experiment comparing case-matched human normal and cancerous prostate tissue in the context of E-cadherin truncation.

Blotting, Western↗