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Biomedical subjects

M A Rubin

Publications and source records attributed to M A Rubin.

102 records · Page 6Linked to original sources
PubMed1990

The pupil response to E-10-hydroxynortriptyline in rabbits with ocular sympathetic paresis.

E-10-hydroxynortriptyline, a metabolite of nortriptyline with half the norepinephrine re-uptake blocking potency of the parent drug, but only 5% of its anticholinergic effect, was as effective as cocaine in demonstrating ocular sympathetic paresis. In five rabbits with unilateral superior cervical ganglionectomies, bilateral 5% cocaine HCl or E-10-hydroxynortriptyline maleate eye drops increased (P less than 0.001) the mean +/- SE anisocoria at 1 h by 1.84 +/- 0.03 mm or 2.16 +/- 0.33 mm, respectively. A single drop of E-10-hydroxynortriptyline did not alter corneal thickness or endothelial cell count.

Animals↗
PubMed1990

Effect of caffeine administration on latent learning ability of male rats in a simple maze task.

Animals can acquire information about the environment in the absence of conventional rewards. This latent or incidental learning depends on their interaction with the environment. The present report examines whether caffeine (120 mumol/kg) could enhance latent learning of a simple maze task by increasing exploratory activity of rats in the maze. Though caffeine increased the activity of rats in the maze under a nonappetitive condition, methylxanthine did not improve performance in rats tested under an appetitive condition in the maze. These results suggest that caffeine (120 mumol/kg) does not facilitate latent learning of a simple maze task. An interesting and unexpected finding of the present study was that caffeine caused greater stimulation of exploratory activity in the open-field than in the maze under nonappetitive conditions. This may be due to differences in the complexity of the two paradigms.

Animals↗
PubMedDate not supplied

Utilization of the emergency department by patients with minor complaints.

Emergency departments (ED) are frequently utilized by patients with minor complaints. It has been a long-standing assumption in the medical community that this use was based on the inability of certain subgroups of the population to access primary care providers secondary to inability to pay. This study examines the use of the ED for minor complaints and the distribution of patients according to mode of payment. Our findings suggest that ED utilization for minor complaints is not, as previously believed, higher in patients with the inability to pay primary care providers. Rather, subsidized patients (Medicare/Medicaid) appear to use the ED equally for major and minor complaints, while there is an increased utilization by commercially insured patients for minor illnesses and injuries, and a lower rate in patients who are self-pay.

Emergency Service, Hospital↗
PubMedDate not supplied

Neuromuscular blocking agents in the emergency department.

Neuromuscular blocking agents (NMBAs) are utilized frequently in the emergency department (ED). We begin with a brief history of neuromuscular blockade, then review the indications and guidelines for its use in the emergency department setting. The relevant agents will be discussed focusing on dosage, side effects, and adverse reactions. Special attention will be paid to succinylcholine, the drug most commonly employed in the ED setting, followed by a summary of the nondepolarizing agents currently available, in particular the four shorter-acting agents that are most appropriate for administration in the ED.

Androstanols↗
PubMedDate not supplied

Profiling and verification of gene expression patterns in normal and malignant human prostate tissues by cDNA microarray analysis.

cDNA microarray technology allows the "profiling" of gene expression patterns for virtually any cellular material. In this study, we applied cDNA microarray technology to profile changes in gene expression associated with human prostate tumorigenesis. RNA prepared from normal and malignant prostate tissue was examined for the expression levels of 588 human genes. Four different methods for data normalization were utilized. Of these, normalization to ACTB expression proved to be the most rigorous technique with the least probability of producing spurious results. After normalization to ACTB expression, 15 of 588 (2.6%) genes examined by array analysis were differentially expressed by a factory of 2x or more in malignant compared to normal prostate tissues. The expression patterns for 8 of 15 genes have been reported previously in prostate tissues (TGFbeta3, TGFBR3, IGFII, IGFBP2, VEGF, FGF7, ERBB3, MYC), but those of seven genes are reported here for the first time (MLH1, CYP1B1, RFC4, EPHB3, MGST1, BTEB2, MLP). These genes describe at least four metabolic and signaling pathways likely disrupted in human prostate tumorigenesis. Reverse transcriptase polymerase chain reaction (RT-PCR) and Northern blot analyses quantitated with reference to ACTB expression levels verified the trends in gene expression levels observed by array analysis for 14/15 and 8/8 genes, respectively. However, RT-PCR and Northern blot analyses accurately verified the "fold" differences in expression levels for only 6/15 (40%) and 7/8 (88%) of genes examined, respectively, demonstrating the need to better validate quantitative differences in gene expression revealed by array-based techniques.

Blotting, Northern↗
PubMedDate not supplied

Loss of expression of human spectrin src homology domain binding protein 1 is associated with 10p loss in human prostatic adenocarcinoma.

The gene encoding human spectrin Src homology domain binding protein 1, or Hssh3bp1, which is a marker of macropinocytic vesicles and a potential regulator of macropinocytosis, co-localizes to a YAC containing chromosome 10p sequences at loci D10S89 and D10S111 that are frequently deleted in prostate tumors. Expression of Hssh3bp1 was evaluated at the protein level in 17 paired normal and malignant prostate tumor samples using the monoclonal antibody 2G8 to Hssh3bp1. These experiments demonstrated that 4/6 tumors (67%) with 10p deletion failed to express Hssh3bp1 protein compared to 5/11 (46%) tumors with intact 10p. Thus, loss of Hssh3bp1 expression is concordant with allelic loss of adjacent 10p sequences in human prostate tumors. In addition, two prostate tumor cell lines contain an exon skipping mutation in the Hssh3bp1 gene that leads to the abnormal splicing of the mRNA and loss of a portion of Abl tyrosine kinase SH3 domain binding site in the protein. These data are consistent with a role for Hssh3bp1 as a candidate tumor suppressor gene inactivated during prostate tumorigenesis.

Adaptor Proteins, Signal Transducing↗
PubMedDate not supplied

Edge complexity and partial volume effects.

PURPOSE: The accuracy of MR brain image segmentation is limited by so-called partial volume effects. We hypothesized that "edge complexity" (i.e., tissue class interface border complexity) significantly influences the magnitude of such effects. METHOD: To investigate partial volume effects and provide a vehicle for validation of segmentation algorithm accuracy in brain MRI. We developed a computer simulation, the "gigabrain." The simulation is based on interpolated (supersampled) data from actual MR studies. The voxels are assigned to one of five compartments (gray matter, white matter, CSF, fat, or "background"), the compartment interfaces are "jittered" to add high frequency "signal" or "edge complexity," and the voxels are populated with appropriate values determined from human data, low pass filtered (based on the MR scanner's point spread function), and subsampled back to the sampling and voxel size of the original MR data set. RESULTS: In comparison studies with actual phantoms and human MR data, our simulation approach was able to produce images whose appearance and quantitative values were comparable with the actual data, but only when edge complexity was added to the original MR data. CONCLUSION: Edge complexity is a significant source of partial volume effects. MR simulations must include edge complexity to adequately test segmentation algorithms.

Adipose Tissue↗
PubMedDate not supplied

Preliminary evaluation of prostate cancer metastatic risk biomarkers.

Prostate cancer patients at high risk of metastasis need to be identified as early as possible since metastasis is invariably fatal. Treatment could be tailored to risk. Recent array comparative genomic hybridization (aCGH) studies of primary and metastatic prostate tumors identified 39 BAC clones capable of detecting genomic signatures of metastasis. We termed these loci the genomic evaluators of metastatic CaP (GEMCaP). Risk assessments were made on a set of men who were managed with radical prostatectomy. We compared the utility of GEMCaP loci and the Kattan nomogram, a common risk assessment tool, in relation to biochemical outcome. This preliminary evaluation experiment suggests we can use aCGH to detect genomic signatures of metastasis in primary tumors with an accuracy of 78%. The classification accuracy for the Kattan nomogram was 75%. Therefore, validation of GEMCaP is warranted in a larger, appropriately designed cohort.

Biomarkers, Tumor↗