Search PubMed⌕ Search

Biomedical subjects

D S Katz

Publications and source records attributed to D S Katz.

At least 37 records · Page 2Linked to original sources
PubMed1999

Fat collection related to the intrahepatic inferior vena cava on CT.

OBJECTIVE: The purpose of our study is to describe the CT findings of fat collections related to the intrahepatic inferior vena cava and to review the literature about this benign incidental finding. CONCLUSION: Focal collections of fat related to the inferior vena cava are benign incidental findings located exclusively at the level of the liver. The fat collections are always adjacent to the medial wall of the inferior vena cava; appear to be extraluminal in origin and may, in fact, be entirely extraluminal; and are uncommon findings that are usually of no clinical significance.

Adipose Tissue↗
PubMed1998

Catalytic center of DNA polymerase beta for excision of deoxyribose phosphate groups.

The amino-terminal 8-kDa domain of vertebrate DNA polymerase beta (pol beta) has an activity to excise deoxyribose phosphate (dRP) groups from 5'-incised apurinic/apyrimidinic (AP) sites during base excision repair. The excision reaction proceeds via a beta-elimination reaction following formation of a Schiff base between an aldehyde group of the AP site and an amino group of the enzyme. Here we report that the Lys-72 residue of this enzyme is the catalytic center for dRP excision. Substitutions of Lys-72 with Arg or Gln reduced the dRP excision activity to less than 1% of the wild-type 8-kDa domain, while substitutions of Lys-35, Lys-68, or Lys-84 did not abolish its activity. The Lys-72 mutations also significantly decreased Schiff base intermediates trapped by reduction with sodium borohydride. The 8-kDa domain alone was able to bind preferentially to a single-nucleotide gap or 5'-incised synthetic AP site on double-stranded DNA. The Lys-72 mutations did not affect this damage-specific DNA binding activity. When introduced into the intact enzyme, a mutation of Lys-72 to Arg did not affect DNA synthesis activity of pol beta, but eliminated the repair activity. Addition of the wild-type 8-kDa domain to this reaction restored the repair activity. These results indicate a specific role of Lys-72 of pol beta in the dRP excision during base excision repair.

Amino Acid Sequence↗
PubMed1998

Chondrosarcoma of the maxilla: panoramic radiographic and computed tomographic with multiplanar reconstruction findings.

Chondrosarcomas are extremely rare tumors of which approximately 10% are found in the maxillofacial region. In this report, we present the imaging findings of a maxillary chondrosarcoma on a panoramic radiograph of the jaws and computed tomography with multiplanar reconstructions. We recommend the latter as an excellent way to image evolving or suspected lesions of the maxilla, particularly for surgical treatment planning.

Adult↗
PubMed1998

Uptake of Tc-99m sestamibi by brown tumors in a patient with primary hyperparathyroidism.

This article discusses a case of Tc-99m sestamibi uptake by brown tumors in a patient with primary hyperparathyroidism. Brown tumors are characteristic tumors of hyperparathyroidism and often have well-defined margins. In this patient with clinical findings of hyperparathyroidism, a retrosternal parathyroid adenoma was identified using Tc-99m sestamibi parathyroid scintigraphy. The adenoma was resected surgically, and the diagnosis was confirmed histopathologically.

Adenoma↗
PubMed1998

Lipomas of the pancreas.

OBJECTIVE: The purpose of this study was to describe the CT findings of pancreatic lipomas in four patients. CONCLUSION: In all four cases, the lipoma was revealed incidentally on CT scans obtained for other reasons. CT scans were diagnostic, showing well-circumscribed masses within the pancreas composed almost entirely of fat, with a few scattered vessels or septa or both, which ranged in size from 1.4 x 2.0 cm to 4.5 x 5.3 cm in the axial plane. Pancreatic lipomas are rare, usually incidental tumors and, as with lipomas found elsewhere in the body, conservative management is often indicated.

Aged↗
PubMed1997

Non-contrast spiral CT for patients with suspected renal colic.

Renal colic, defined as acute flank pain caused by the passage of a ureteral calculus, is a common condition, but the correct diagnosis may not be apparent clinically. For decades, intravenous urography has been the test of choice for evaluating patients with suspected renal colic. Recently, unenhanced (non-contrast) helical CT has been shown to be an accurate and highly effective examination which can be used instead of intravenous urography. In this article, the technique is reviewed in detail, including its advantages and potential pitfalls.

Adult↗
PubMed1997

Spontaneous intramural small bowel haemorrhage: importance of non-contrast CT.

The purpose of this study was to evaluate the abdominal CT findings in patients with spontaneous intramural small bowel haemorrhage. We retrospectively reviewed the abdominal CT scans of six patients with known intramural small bowel haemorrhage. All of the patients had an underlying coagulopathy. All six patients underwent CT examinations without oral or intravenous contrast media. All six non-contrast CT scans showed hyperattenuation of the involved bowel segments, with thickened and dilated proximal small bowel. Therefore, patients who are clinically at risk for intramural small bowel haemorrhage should undergo a non-contrast CT scan of the abdomen prior to the routine oral and intravenous contrast-enhanced scan. In most cases the non-contrast scan will provide definitive diagnostic information which may not be evident from the contrast-enhanced scan alone.

Adult↗
PubMed1997

Unenhanced helical CT for suspected acute appendicitis.

OBJECTIVE: The purpose of this study was to determine the diagnostic accuracy of unenhanced helical CT scans in patients with a suspected acute appendicitis. SUBJECTS AND METHODS: Over a 20-month period, 109 adult patients with suspected acute appendicitis were referred by the emergency department for an unenhanced helical CT scan. Each scan was obtained in a single breath-hold from the T12 vertebral body to the public symphysis using a 5-mm collimation and a pitch of 1.6. No patients were given oral or IV contrast media. The primary CT criteria for diagnosing acute appendicitis was the identification of an appendix with a transverse diameter larger than 6 mm with associated periappendiceal inflammatory changes. The presence of an appendicolith was considered a secondary finding as was isolated periappendiceal inflammation; however, appendicitis was not diagnosed in such patients unless an enlarged appendix was definitely identified. Final diagnoses were established by surgical or clinical follow-up and were compared with the original CT reports. RESULTS: We found 66 true-negatives, 37 true-positives, four false-negatives, and two false-positives that yielded a sensitivity of 90%, a specificity of 97%, a positive predictive value of 95%, a negative predictive value of 95%, and an accuracy of 94%. An alternative diagnosis was established by an unenhanced helical CT scan in 24 patients (22%), which included cecal diverticulitis (seven patients), urinary tract disease (five patients), adnexal pathology (four patients), sigmoid diverticulitis (two patients), small bowel disease (three patients), right lower quadrant tumor (two patients), and an infected dialysis catheter (one patient). CONCLUSION: Unenhanced thin-section helical CT is an accurate, effective technique for diagnosing acute appendicitis.

Acute Disease↗