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Biomedical subjects

S Schechter

Publications and source records attributed to S Schechter.

18 recordsLinked to original sources
PubMed1996

Synchronous colon carcinomas: molecular-genetic evidence for multicentricity.

BACKGROUND: The synchronous presentation of multiple colonic adenocarcinomas is an unusual, but well-recognized event accounting for approximately 2-11% of these neoplasms. Synchronous tumors may have a different biology and prognosis than solitary tumors. Evidence based on measurement of DNA ploidy suggests that a significant percentage of synchronous tumors have a common clonal origin, probably resulting from translumenal metastasis. METHODS: Fifteen synchronous colorectal cancers (30 tumors) were examined for histologic differences as well as genetic mutations. p53 gene abnormalities were detected by polymerase chain reaction (PCR) followed by single-strand conformation polymorphism analysis. Ki-ras mutations were detected by PCR followed by oligonucleotide-specific hybridization. RESULTS: p53 gene mutations were detected in 12 of 30 tumors. In only one case was the same p53 mutation present in both tumors from one patient. Similarly, Ki-ras mutations were observed in 9 of 30 tumors. Concordant Ki-ras mutations were observed in only one case, which was also concordant for p53 mutation. CONCLUSION: Because p53 and Ki-ras mutations tend to occur fairly early in tumor development, it seems likely that cases discordant for p53 and Ki-ras mutations represent independently developing tumor foci. Taken together, these findings strongly suggest that the great majority of synchronous colonic adenocarcinomas arise as independent neoplasms and their worsened prognosis is not a result of unusually early metastatic spread.

Adenocarcinoma↗
PubMed1994

Computerized tomographic scan-guided drainage of intra-abdominal abscesses. Preoperative and postoperative modalities in colon and rectal surgery.

PURPOSE: Computerized tomographic (CT) scan-guided percutaneous drainage of intra-abdominal abscesses has changed the colon and rectal surgeon's approach to preoperative and postoperative intra-abdominal infections. This study is an effort to prove the efficacy of CT scan-guided percutaneous drainage. METHODS: A retrospective study was performed on 133 patients who underwent CT scan drainage of intra-abdominal abscesses over a 6.3-year period. RESULTS: 67 patients had underlying lower gastrointestinal disease. Twenty-three of these patients (34 percent) had spontaneous abscesses and underwent drainage as a preoperative or final modality, whereas 44 patients (66 percent) were drained postoperatively. In 78 percent of patients, surgery was successfully avoided or delayed. Ten patients had acute diverticulitis associated with a large pelvic abscess. Eight patients underwent successful CT scan-guided percutaneous drainage, yielding an 80 percent success rate. Morbidity from the CT scan-guided percutaneous drainage procedure in spontaneous and postoperative groups was 0 percent and 9 percent, respectively. Mortality was 9 percent and 11 percent, respectively, and associated with an elevated Acute Physiology and Chronic Health Evaluation II (APACHE II) score. CONCLUSION: CT scan-guided percutaneous drainage of intra-abdominal abscesses is an important adjunct to colon and rectal surgery because roughly 80 percent of spontaneous and postoperative abscesses were successfully managed.

Abdominal Abscess↗
PubMed1994

Simple method for polyp retrieval during colonoscopy.

Retrieval of small polyps can often be frustrating for the skilled endoscopist. We introduce a technique of polyp retrieval that is simple and effective in yielding intact specimens for accurate pathologic examination.

Biopsy↗
PubMed1992

Recurrent breast cancer: stereotaxic localization for fine-needle aspiration biopsy. Work in progress.

The efficacy of stereotaxic localization for fine-needle aspiration biopsy in the detection of recurrent cancer manifested as calcifications on mammograms was evaluated in 43 patients that had been treated with local resection and radiation therapy. Six patients had malignant aspirates and one had an atypical aspirate; examination of the surgical specimens revealed all seven of these to be malignant. Thirteen patients underwent surgical biopsies, the results of which were malignant in seven and benign in six. The remaining 30 patients were followed up with mammography. The follow-up mammograms were obtained at 6-month intervals and demonstrated no change in appearance. On the basis of this initial experience, stereotaxic localization for aspiration biopsy offers the potential to accurately distinguish benign from malignant lesions.

Adenocarcinoma↗
PubMed1992

AIDS patients.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Invasive papillary carcinoma of the breast: mammographic appearance.

The mammographic findings in 18 patients with invasive papillary carcinoma were studied retrospectively. The mammograms of 10 patients showed a multinodular pattern, and seven patients had solitary nodules. One patient had an irregular, ill-defined mass in the retroareolar region. Two patients were found to have carcinoma in the contralateral breast, and two patients had intraductal carcinoma adjacent to the invasive papillary carcinoma. The varied mammographic features that may occur with this rare breast malignancy are discussed.

Aged↗
PubMed1987

Neonatal duodenum: fluid-aided US examination.

In 261 infants with vomiting, 11 duodenal abnormalities were diagnosed with fluid-aided ultrasound (US). These abnormalities included duodenal obstruction, malrotation with and without associated volvulus, incomplete rotation, and duodenal stenosis. US was the initial modality used in the evaluation of vomiting in these neonates and young infants. The overall sensitivity and specificity of fluid-aided US evaluation of duodenal abnormalities were 100% and 99%, respectively. (Workup bias limits the reliability of these figures.) Fluid-aided US examination of the stomach and duodenum provided a dynamic view of duodenal rotation and anatomy, and at the very least provided a method of triaging those infants who may require surgery, upper gastrointestinal series, or follow-up US to make a definitive diagnosis.

Duodenal Obstruction↗
PubMed1987

Ultrasonic "double track" sign in hypertrophic pyloric stenosis.

Ultrasound has been used in the diagnosis of hypertrophic pyloric stenosis since the first reports of its use with contact B mode scanners. Real-time imaging has allowed measurements of pyloric diameter, length, and muscle wall thickness. Wall thickness measurements taken with the pylorus in longitudinal (elongated) view improve diagnostic accuracy. Fluid aided real-time examination of 10 cases showed the ultrasound equivalent of the "double track" sign. This finding is the result of pyloric fluid compressed into smaller tracks as it is impinged upon circumferentially by the thickened circular muscle. This sign, previously seen in barium studies, although nonspecific, may prove to be a sensitive diagnostic criterion.

Female↗
PubMed1986

Renal candidiasis of the infant: ultrasound evaluation.

Sonographic diagnosis of 3 cases of renal candidiasis led to early diagnosis and treatment. Echogenic densities within a dilated pyelocalyceal system appeared to be the classic finding for obstructing candidal bezoars or candidal pyonephrosis in the premature neonate. Sonography was useful in guiding diagnostic and therapeutic percutaneous nephrostomies of very premature (900 and 750 g) infants. The ultrasonic findings of moderate echogenicity within dilated collecting systems in premature infants suggest pyonephrosis. Candidiasis should be considered as a prime cause.

Candidiasis↗
PubMed1985

Imaging of psoas muscle abscess in adolescents with Crohn's disease.

Two adolescents with psoas muscle abscesses secondary to Crohn's disease are presented. Musculoskeletal signs of hip flexion and scoliosis led to early clinical suspicion. Computed tomography and ultrasonography demonstrated the extent of involvement and allowed specific preoperative diagnosis.

Abscess↗
PubMed1984

Analysis of the mechanism of ATP stimulation of calf thymus DNA alpha-polymerase.

Biochemical kinetic analyses of the ATP stimulation of the A2 form of calf DNA alpha-polymerase show that when DNA or primer termini are the variable substrates, maximum reaction velocity is independent of ATP concentration. When dNTP concentration is the variable substrate, the apparent Km is invariant with ATP. Such results indicate that the increase in the synthetic rate caused by ATP results from an improvement in synthesis initiation at primer termini. The effect of ATP on the DNA binding affinity of alpha-A2-polymerase was examined by using column chromatography. Passage of the polymerase through native DNA-cellulose at 70 mM ionic strength resulted in 40% binding of the enzyme. In the presence of 4 mM ATP, binding increased to 80%. In both cases, the bound polymerase could be eluted by a 370 mM ionic strength wash. An elution profile similar to that observed in the absence of ATP was obtained with 0.1 mM ATP, 4 mM GTP, or 4 mM each of the nonhydrolyzable ATP analogues adenyl-5'-yl imidodiphosphate or adenosine 5'-O-(3-thiotriphosphate). These results suggest that hydrolysis of the gamma-phosphate occurs at millimolar levels of ATP and leads to a higher affinity of polymerase for DNA. To distinguish the effects of ATP on RNA priming from those on DNA synthesis, products synthesized processively by alpha-A2-polymerase were sized by gel filtration. Results indicate that essentially all products made on a gapped fd replicative form template in the presence of four dNTPs and 4 mM ATP result from the extension of preexisting DNA primers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1984

Choosing and using a vehicle.

The amount of topical medication needed to cover the body thinly by self-application was measured in twenty-nine adults. It averaged 22 gm and varied with surface area and size of container, but not with sex or instruction. There was no difference in amount used between cream and ointment or between alcoholic liquid and creamy liquid. Application by a trained attendant required less medication than self-application. Self-application of a fluorescent sunscreen skipped many areas.

Administration, Topical↗
PubMed1983

Chloride ion transport and its inhibition in thylakoid membranes.

Cl- translocation across energized and nonenergized thylakoid membranes was found to be inhibited by piretanide, an inhibitor of active Cl- transport in fish intestinal epithelia. Piretanide has no effect on photophosphorylation catalyzed by phenazine methosulfate or on Ca2+-dependent ATPase activity of isolated chloroplast coupling factor (CF1). Light-dependent Cl- uptake, contrary to H+ uptake, is severalfold greater at pH 8.0 than at pH 6.7.

Biological Transport↗