Search PubMed⌕ Search

Biomedical subjects

M B Cohen

Publications and source records attributed to M B Cohen.

At least 127 records · Page 7Linked to original sources
PubMed1995

Clinical experience with transvenous implantable cardioverter-defibrillators for treatment of malignant ventricular arrhythmias.

The need for thoracotomy has previously limited the use of the implantable cardioverter-defibrillator. Prior investigators have shown the efficacy and reduced risk of the transvenous implantable cardioverter-defibrillator. In this study, we report our experience with the transvenous implantable cardioverter-defibrillator as a first-line system. Thirty-four patients with mean age 63.2 +/- 10.3 years and mean ejection fraction 32.6 +/- 11.4% underwent implantation of a transvenous cardioverter-defibrillator using an Endotak lead with or without a subcutaneous patch. Twenty-one patients received a biphasic device and the remainder a monophasic device. Thirty-three of 34 patients (97%) were successfully implanted. The mean defibrillation threshold was than < or = 15.3 +/- 3.6J. Overall, 25 of 34 (74%) patients were implanted with a single endocardial lead alone. In the group receiving a biphasic device 19 of 21 (90%) were successfully implanted with a single endocardial lead alone whereas in the group receiving a monophasic device only 6 of 12 (50%) were successfully implanted with single endocardial lead alone (p < 0.05). There were no serious complications. One postoperative death was a result of end-staged congestive heart failure. We conclude that the transvenous implantable cardioverter-defibrillator is safe and efficacious and that incorporation of biphasic waveform may lead to higher rates of implantation of single transvenous lead alone without the need for subcutaneous patch.

Adult↗
PubMed1995

Histopathological features and p53 nuclear protein staining as predictors of survival and tumor recurrence in patients with transitional cell carcinoma of the renal pelvis.

PURPOSE: We determine which histopathological features are predictive of recurrence and cause-specific survival in renal pelvic transitional cell carcinoma. MATERIALS AND METHODS: Univariant and multivariant analysis was done on material from 67 patients. RESULTS: Univariate and multivariate analysis identified lamina propria invasion, grade 3 tumors and capillary-lymphatic invasion as predictors of disease-specific survival. Multicentric disease was the sole independent predictor of recurrence. Multicentric disease and lamina propria invasion were independent predictors of recurrence-free survival. Also, p53 over-expression was not statistically associated with any of the studied prognostic factors. CONCLUSIONS: Histopathological features remain the cornerstone of prognostic assessment for renal pelvic transitional cell carcinoma.

Adult↗
PubMed1995

Laboratory use of the diagnosis "reactive/reparative" in gynecologic smears: impact of CLIA '88.

The Clinical Laboratory Improvement Amendments of 1988 (CLIA '88) contain regulation 493.1257(c)(1), which states: "[A]ll gynecologic smears interpreted to be showing reactive or reparative changes are confirmed by a technical supervisor in cytology." We surveyed 500 cytology laboratories to assess the utilization of the diagnosis "reactive/reparative" (R/R) for gynecologic cytology examinations. One hundred and seventy participants (34%) returned an acceptable questionnaire that described their use of this terminology, the technical supervisor's (pathologist's) role in the evaluation of these cases, and the volume of cases with this diagnosis. Prior to CLIA '88, 86 (51%) laboratories did not forward to a pathologist gynecologic smears reported as showing R/R changes, and this decreased to 20 (12%) after implementation of CLIA '88. Thirty-six (21%) laboratories changed their criteria for reporting R/R changes after CLIA '88. No correlation was noted between the demographics of the laboratory (e.g., size, type of practice affiliation, accreditation) and familiarity with this regulation. Based on the case volumes provided in the survey results, the estimated cost to the nation of complying with this single regulation is between $4.5 million and $40 million. The interpretation of and financial impact of compliance with this one selected regulation of CLIA '88 is reported.

Cytological Techniques↗
PubMed1995

p53 immunoreactivity in primary and metastatic prostatic adenocarcinoma.

p53 is a tumor suppressor protein that is overexpressed in a variety of human neoplasms, including prostatic adenocarcinoma. Recent studies have demonstrated a significant positive correlation between extent of p53 overexpression and tumor grade in prostatic adenocarcinoma. Because it appears that mutations of p53 might play a role in the pathogenesis of a subset of biologically aggressive prostatic neoplasms, we sought to examine the frequency of p53 overexpression in primary and metastatic prostatic adenocarcinoma. Using a monoclonal antibody (D07) directed against both the wild-type and mutant forms of p53, we examined p53 immunoreactivity in 36 cases of primary prostatic adenocarcinoma, 17 cases of metastatic prostatic adenocarcinoma involving lymph nodes and 15 cases of metastatic prostatic adenocarcinoma involving bone. Twenty-eight percent (10/36) of the primary tumors displayed nuclear staining for p53. Increased p53 immunoreactivity was observed in only 6% (1/16) of prostatic adenocarcinomas with a total Gleason score of 6 or less, as compared with 45% (9/20) of those adenocarcinomas with a Gleason score of 7 or more. Fifty-nine percent (10/17) of the lymph node metastases and 43% (6/14) of the bone metastases displayed nuclear immunoreactivity for p53. Our results indicate that increased p53 expression is positively correlated with increased histologic grade and with the presence of metastatic disease in patients with prostatic adenocarcinoma, and they suggest that mutations of the p53 gene may play a role in mediating the behavior of a biologically aggressive subset of this common neoplasm.

Adenocarcinoma↗
PubMed1995

Brush cytology of the extrahepatic biliary tract: comparison of cytologic features of adenocarcinoma and benign biliary strictures.

Malignant strictures of the extrahepatic biliary tract are difficult to discern from benign strictures solely by clinical and/or radiographic findings. Endoscopic retrograde wire-guided brushings of strictures have proven to be useful in evaluating such lesions. Because the reported sensitivity of diagnosing adenocarcinoma of the extrahepatic biliary tract by this technique has varied considerably (44 to 100%), we undertook a retrospective study to determine if the diagnostic accuracy could be increased by identifying key cytologic features by reviewing a series of 90 biliary tract brushings from 80 patients. The cytologic diagnosis was confirmed either by additional pathologic material and/or clinical follow-up. Utilizing a multiple logistic regression analysis, three key cytologic features were identified that were useful in separating benign from malignant strictures; these features included: nuclear molding, chromatin clumping, and increased nuclear-cytoplasmic ratio. The presence of two of these three features resulted in a sensitivity of 83%; the corresponding specificity was 98%. The use of these key features should aid the cytologist in better recognizing malignant cells in biliary tract brushings.

Adenocarcinoma↗
PubMed1995

Microsatellite instability in adenocarcinoma of the prostate.

Instability of dinucleotide tandem repeat sequences has been reported to play a major role in the carcinogenic pathway of familial colon cancer, as well as a potential role in the carcinogenesis of other sporadic neoplasms. To determine the frequency of short tandem repeat instability in adenocarcinoma of the prostate, we studied 40 tumors that were stratified according to tumor grade. The tissue samples were screened with di-, tri- and tetranucleotide markers spanning a wide range of chromosomal loci, including an androgen receptor gene trinucleotide repeat. Microsatellite instability was observed overall in only one of the 40 (2.5%) prostate adenocarcinomas studied. This replication error-positive tumor demonstrated repeat length alterations at two loci. Five other tumors showed an alteration in microsatellite size at a single locus. These tumors were not considered to have the microsatellite instability phenotype. All changes were identified either within tetranucleotide sequences or within the androgen receptor gene repeat (4 or 20 total markers analyzed). Both repeat length expansions and contractions were identified. The replication error-positive case also included separate metastatic nodal tissue. Additional microsatellite analysis of the metastatic tumor tissue revealed allelic patterns identical with the normal tissue control. Our data indicate that microsatellite instability is rare in prostate adenocarcinoma. Therefore, observation of this low replication error frequency suggests that most prostate carcinomas develop in the absence of widespread accumulation of somatic mutations in short tandem repeat sequences. Additionally, these genetic alterations appear to occur more often in tetranucleotide repeat sequences as well as in an androgen receptor gene trinucleotide repeat.

Adenocarcinoma↗
PubMed1995

Use of a single solution for oral rehydration and maintenance therapy of infants with diarrhea and mild to moderate dehydration.

OBJECTIVE: To compare the efficacy of two commonly used solutions in the rehydration of infants with mild to moderate dehydration caused by acute diarrhea in the United States. DESIGN AND SETTING: Double-blind, parallel-group, randomized study performed at Children's Hospital Medical Center. PATIENTS: Sixty infant boys (< or = 2 years old), with mild (< or = 5%) or moderate (6 to 9%) dehydration caused by acute diarrhea of less than 1 week's duration were included in the study. INTERVENTIONS: Infants were randomly assigned to receive treatment with either a glucose-based oral rehydration solution (ORS) (Pedialyte, Ross Laboratories, Columbus, OH) or a rice syrup solids-based ORS (Infalyte, Mead Johnson Nutritional Group, Evansville, IN). After rehydration was achieved, patients entered a maintenance phase during which, in addition to a maintenance ORS, breast milk or a soy-based formula was offered; infants older than 1 year were also given a lactose-free diet. OUTCOME MEASURES: Rehydration was judged clinically. Infants remained on a metabolic bed during the study in to separate and quantitate urine and stool output. Therefore, in addition to clinical outcome, we compared intake, output and apparent absorption and retention of fluid, sodium, and potassium between groups. RESULTS: All patients were successfully rehydrated using an ORS without the use of intravenous fluids. No differences were detected between treatment groups in time to rehydration, percentage of weight gain after rehydration, consumption of ORS to achieve rehydration, or stool output. However, the apparent sodium absorption (net intake less fecal output) was greater in the Infalyte group than the Pedialyte group during the first 24 hours. CONCLUSION: The two maintenance oral electrolyte solutions (Pedialyte and Infalyte) most commonly used in the United States are effective as rehydration solutions for infants with mild to moderate dehydration. We speculate that a strategy for oral rehydration therapy in the United States, based on the use of a single solution during the rehydration and maintenance phase, might gain additional acceptance by practicing pediatricians and family physicians.

Acute Disease↗
PubMed1994

Structure and chromosomal localization of CYP6A1, a cytochrome P450-encoding gene from the house fly.

We determined the sequence of a cytochrome P450-encoding gene, CYP6A1, in an insecticide-resistant strain (Rutgers) and in insecticide-susceptible strains (aabys and sbo) of the house fly Musca domestica. The deduced amino acid (aa) sequence of CYP6A1 is 98% identical between Rutgers and aabys, and it is identical between Rutgers and sbo. Differences in aa sequence occur in regions that are not thought to participate in the active site. CYP6A1 has a single intron, 60 bp in length. It does not occur in a position homologous to intron sites in genes of the related CYP3 family or other vertebrate P450 families. We mapped the transcription start point (tsp), TATA box and barbie box [Shaw and Fulco, J. Biol. Chem. 269 (1993) 2997-3004] of this phenobarbital-inducible gene. Although overexpression of CYP6A1 in strain Rutgers is controlled by a locus on chromosome II [Cariño et al., Insect Biochem. Mol. Biol. 24 (1994) 411-418], we have localized CYP6A1 to chromosome V, thus showing that a trans-acting factor controls the overexpression of the gene in the Rutgers strain.

Amino Acid Sequence↗
PubMed1994

Low grade transitional cell carcinoma of the bladder. Cytologic diagnosis by key features as identified by logistic regression analysis.

BACKGROUND: Bladder cytology is being used increasingly to detect and monitor early stage bladder cancer. Because of the lack of significant cytomorphologic atypia in low grade transitional cell carcinomas (TCCs), there often is great difficulty in separating these neoplastic cells from benign urothelial cells. METHODS: In an attempt to increase diagnostic sensitivity, 82 bladder wash specimens, which included 33 low grade TCCs and 49 nonneoplastic lesions, were reviewed retrospectively. With a stepwise logistic regression analysis, three key cytomorphologic criteria useful in the separation of low grade TCC from benign urothelium were identified. RESULTS: The key cytologic criteria were increased nuclear/cytoplasmic ratios, irregular nuclear borders, and cytoplasmic homogeneity. By using contingency tables, these three criteria combined had a sensitivity of 45% and a specificity of 98% in the diagnosis of low grade transitional cell carcinoma. If any two of the criteria were present, there was a sensitivity of 85% and a specificity of 96%. CONCLUSIONS: By using these three criteria, the diagnosis of TCC can be made with a high degree of accuracy in bladder wash specimens.

Adult↗
PubMed1994

Iodixanol, a new isosmotic nonionic contrast agent compared with iohexol in cardiac angiography.

Iodixanol, a new ratio 6 nonionic iodinated contrast agent with an osmolality equal to serum, was compared with iohexol in a randomized, double-blind, parallel study. Two hundred patients undergoing elective diagnostic cardiac angiography were randomized to iodixanol (n = 101) or iohexol (n = 99). There were no differences noted between the 2 agents in the mean changes in systolic or diastolic blood pressure or heart rate during or immediately after any angiography. However, significantly more patients had a decrease in diastolic blood pressure of > 20 mm Hg during left coronary angiography with iodixanol. The only significant differences in any electrophysiologic parameter were slightly more PR prolongation during left coronary angiography with iodixanol and more ST-segment depression with iohexol during coronary angiography. Neither was clinically significant. Injection-associated discomfort occurred with both agents, but more patients experienced moderate to severe discomfort with iohexol (52%) than with iodixanol (17%) (p < 0.001). Only 1 potentially serious adverse event, ventricular fibrillation with iohexol, was considered related to contrast, and there were no differences noted between the agents. Overall, angiographic quality was equal with all angiograms being assessed as good or excellent in both groups (p = 0.885). In this low-risk population undergoing cardiac angiography, iodixanol is safe and effective without clinically important differences from iohexol. Additional studies in patients at high risk for complications should help further define the role of iodixanol in cardiac angiography.

Blood Pressure↗
PubMed1994

Black swallowtail (Papilio polyxenes) alleles encode cytochrome P450s that selectively metabolize linear furanocoumarins.

Cytochrome P450 monooxygenases are involved in metabolism of hostplant allelochemicals by larval Lepidoptera. Biochemical purification of the P450 polypeptide induced in Papilio polyxenes (black swallowtail) larvae in response to xanthotoxin, a linear furanocoumarin, has allowed us to clone cDNAs encoding two allelic variants of the CYP6B1 locus. Expression of these alleles in lepidopteran cell lines using baculovirus expression vectors has demonstrated that both P450 isoforms metabolize substantial amounts of linear furanocoumarins, such as xanthotoxin and bergapten, but not angular furanocoumarins, such as angelicin and sphondin. These linear furanocoumarins are ubiquitous constituents of the hostplants of P. polyxenes. The efficiency of linear furanocoumarin metabolism is strongly affected by the nature of the substituents on the benzene ring; methoxy-derivatives are metabolized more efficiently than are derivatives with smaller (hydroxy-) or larger (8-O isopentenyl) groups. Metabolism of either bergapten or xanthotoxin is inhibited in the presence of the other. In addition, metabolism of linear furanocoumarins is inhibited by the presence of nonmetabolizable angular furanocoumarins, indicating that the active site of CYP6B1 binds angular furanocoumarins. The reactivities described here indicate that P. polyxenes larvae express at least two selective furanocoumarin-metabolic P450s: CYP6B1, which metabolizes a discrete set of linear furanocoumarins, and another P450, as yet unidentified, which metabolizes angular furanocoumarins more efficiently than does CYP6B1.

Alleles↗
PubMed1994

Gross and microscopic pathology of induced prostatic complex tumors arising in Lobund-Wistar rats.

The necessity for additional animal models for prostate cancer has recently been stressed. The Pollard model of chemically induced prostate cancer has received attention in this regard although the histiogenetic origin of these tumors has come under question. We independently studied this model for the development of tumors in the prostate region. The tumors, all of which were adenocarcinomas, first became grossly evident 5 months after induction and ultimately occurred in 71% of the animals. Seventy-three % of the tumors involved only the seminal vesicle, 22% involved other portions of the prostatic complex as well as the seminal vesicle, and 5% were located in the coagulating gland (anterior prostate). Although the majority of tumors arose in or involved the seminal vesicle, this may still be a useful model for the study of human prostate cancer because the tumors are adenocarcinomas, occur in the large majority of animals, are hormonally induced, and have the propensity to metastasize.

Adenocarcinoma↗
PubMed1994

Malignant rhabdoid tumor of the uterus: report of a case with findings in a cervical smear.

Rhabdoid tumors are an uncommon group of neoplasms which share a distinctive morphology. We report the cytologic and histologic findings of a uterine rhabdoid tumor. The presence of rhabdoid cells on a cervical Papanicolaou (Pap) smear raises an intriguing differential diagnosis. Cytologists should be aware of this entity and consider rhabdoid tumor in the differential diagnosis when single malignant cells are noted on cervical Pap smear.

Female↗
PubMed1994

Paranuclear blue inclusions in small cell undifferentiated carcinoma: a diagnostically useful finding demonstrated in fine-needle aspiration biopsy smears.

In a study of bone marrow aspiration smears, Wittchow et al. (Mod Pathol 1992;5:555-558) described a highly characteristic finding, paranuclear blue inclusions (PBIs), found almost exclusively in cases of metastatic small cell undifferentiated carcinoma (SCUC). PBIs are 1-4 microns, light blue, cytoplasmic inclusions best visualized with Romanowsky-type stains. These inclusions are most easily found indenting the nuclei within clusters of closely opposed tumor cells. In the current study air-dried fine-needle aspiration biopsy (FNAB) smears from 146 primary and metastatic small cell and non-small cell adult and childhood malignancies were reviewed. PBIs were found in 28/32 (88%) of SCUC but were observed in only 4/44 (9%) non-small cell carcinomas, 2/21 (9.5%) lymphomas, 1/8 (12.5%) melanomas, 0/14 sarcomas, and 6/27 (22%) small round cell neoplasms. These results suggest that the presence of PBIs in air-dried FNAB smears of adult neoplasms, while not pathognamonic of SCUC, are a diagnostically useful finding. PBIs may be seen in a variety of different childhood small round cell neoplasms which limits their utility in this setting. The recognition of PBIs is most important to the cytologist who may not have access to ancillary studies, such as immunohistochemistry and electron microscopy.

Biopsy, Needle↗
PubMed1994

Laboratory compliance with federal government and professional society recommendations.

Quality assurance issues have assumed growing importance in the cytology laboratory. The 1988 Clinical Laboratories Improvement Amendment (CLIA '88) (United States Department of Health and Human Services, Federal Register: U.S. Government Printing Office 1990;55:9495) regulates the patient identifiers and clinical data on the requisition form but does not mandate physician compliance to provide the information. We investigated the use of patient identifiers and clinical data by laboratories as specimen acceptance/rejection criteria. We surveyed 81 board certified cytopathologists and 235 randomly selected cytology laboratories for acceptance criteria of cytology specimens and received responses from 104. Approximately two thirds of all responding laboratories had specific criteria for rejecting specimens on the basis of inadequate identification or clinical data. While the vast majority required the specimens to be identified with patient name, collection date, and specimen source, a minority of laboratories required clinical information such as LMP, prior atypical cytologic/histologic specimens, and history of previous therapy. Little correlation was found between practice setting and the use of rejection criteria.

Laboratories↗
PubMed1994

Fine-needle aspiration biopsy of salivary gland mycoses.

This report details the fine-needle aspiration biopsy (FNAB) cytomorphologic features of two cases of salivary gland mycosis. Both patients had acquired immunodeficiency syndrome (AIDS) and presented with parotid gland masses. The first patient had Histoplasmosis with secondary infection by Candida. Cytopathologically, the FNAB smears showed classic features of a deep-seated mycosis characterized by necrosis and scattered fungal forms. The second patient had a colonizing sialadenitis caused by either Asperigillus or Fusarium. Cytopathologically, the findings were similar to those seen in aspergillomas of the lung or paranasal sinuses with numerous hyphal forms and an absence of an inflammatory response. Because mycotic disease can induce a wide spectrum of pathogenic change, other benign or malignant, solid or cystic lesions enter into the differential diagnosis.

AIDS-Related Opportunistic Infections↗
PubMed1994

Extraskeletal myxoid chondrosarcoma: fine-needle aspiration biopsy findings.

Extraskeletal myxoid chondrosarcoma (EMC) is a malignant soft tissue tumor which typically presents as an enlarging mass in an extremity. In this location it is amenable to sampling and diagnosis by fine-needle aspiration biopsy. We present our experience with three cases of EMC and discuss the differential diagnosis of myxoid soft tissue tumors.

Aged↗