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Biomedical subjects

L Roberts

Publications and source records attributed to L Roberts.

At least 307 records · Page 17Linked to original sources
PubMed1986

Esophageal cancer staging by CT: long-term follow-up study.

To evaluate the utility of computed tomographic (CT) staging in patients with esophageal cancer, the length of patient survival was compared with pretherapy CT findings in 89 patients. Regardless of therapy, patients with evidence of mediastinal invasion, liver metastases, or abdominal adenopathy had a statistically shortened survival (P less than .05). Specific CT criteria that predicted a shortened survival included evidence of tracheal, aortic, or pericardial invasion. Patients with evidence of both mediastinal invasion and abdominal metastases had a mean survival of 180.4 days; those with no evidence, 479.6 days. The presence of enlarged upper abdominal lymph nodes indicated the worst prognosis (mean survival, 90 days). The patients with squamous cell tumors were classified by the CT staging system, and survival data were compared according to surgical procedure. Patients who underwent attempted curative surgery did not have a statistically significant difference in survival by analysis of survival curves but demonstrated a longer mean survival than those who underwent palliative or no surgery.

Adult↗
PubMed1986

Acute parathyroid hormone secretory dynamics: hormone secretion from normal primate and adenomatous human tissue in response to changes in extracellular calcium concentration.

PTH secretion has been evaluated extensively using short term incubation techniques, but these methods cannot be used to adequately evaluate the early phases of PTH secretion. We developed a dispersed cell perifusion system to study these acute secretory events. Responses to low calcium conditions were studied using dispersed cells from normal primate and adenomatous human parathyroid tissue. When these cell were perifused with 1.0 mM calcium medium, PTH secretion was stable, but increased within minutes in a dose-dependent manner in response to a lowering of extracellular calcium concentrations. Similarly, PTH secretion quickly declined when cells were exposed to higher extracellular calcium concentrations. In studies of cells from 11 human adenomas, the mean maximum secretion in response to 0.25 mM calcium conditions was 587 +/- 330% (+/- SD) of that in response to 1.0 mM calcium. The magnitude of the response to low calcium stimulation was variable, and cells from two additional adenomas failed to respond to low calcium stimulation despite responses to other secretogogues. Variation in the rate of increase in stimulated PTH secretion was also found among the adenomas examined (128 +/- 95% of baseline/min), and the rate of increase in PTH release and the eventual maximum rate of release were positively correlated. In studies of cells from 4 normal primates (rhesus macaque), the maximum response to 0.25 mM Ca2+ (544 +/- 118% of baseline) and the rate of increase in PTH secretion (95 +/- 35% of baseline/min) were similar to those in adenomatous human tissue. These results indicate that 1) acute PTH secretion can be studied in vitro, and that it appears to be similar to the in vivo process; 2) there is a wide variation among adenomatous tissues in the magnitude of secretion stimulated by low calcium concentrations; 3) in addition to varied magnitude of secretion, the rate at which hormone secretion increases in response to a low calcium stimulus varied among adenomas; and 4) PTH secretion from human adenomatous tissue is similar to that from normal primate tissue in both the rate and magnitude of response.

Adenoma↗
PubMed1986

Optimal cholangiographic technique for detecting bile duct stones.

Twenty-eight patients with proven bile duct stones were evaluated during either operative or T-tube cholangiography. Two radiographs were obtained for each patient without changing patient position between films. The first was performed with low peak kilovoltage (75-80 kVp) and 15% iodinated contrast medium and the second with high kVp (110) and 38% iodinated contrast. Seven radiologists evaluated the radiographs individually and in matched pairs for ductal filling, ductal penetration, motion unsharpness, overall quality, and stone detectability. The high-kVp radiographs were rated significantly better overall than the low-kVp studies (p less than 0.001) for all five criteria. In the second evaluation, which compared the pairs from the same patients, the 28 high-kVp radiographs were considered superior to the 28 low-kVp studies by the radiologists in almost two-thirds of the comparisons (ductal filling, 68%; penetration, 59%; less motion unsharpness, 65%; overall quality, 77%; stone detection, 62%). On the basis of the results of this study, high-kVp technique with full-strength contrast medium for operative and T-tube cholangiography is recommended.

Cholangiography↗
PubMed1986

Preoperative and postoperative CT staging of rectosigmoid carcinoma.

This study reports a 4 year experience using CT for preoperative staging and for evaluation of patients with rectal and sigmoid carcinoma after surgery. All patients were evaluated on a GE 8800 scanner using 1 cm contiguous slices. Only 15 of the 25 preoperative patients were staged correctly. The other 10 patients were understaged by CT. The accuracy of detecting local invasion was 70%, but only seven (35%) of 20 patients had accurate assessment of lymph nodes. The overall accuracy of CT staging in the 46 postoperative patients was 87%, with a sensitivity of 91% and a specificity of 72%. Most recurrences were found in the pelvis; 16 patients had liver metastases, and metastatic disease obstructing the ureters was detected in eight patients. On the basis of these results, it was concluded that CT should not be used routinely to preoperatively stage patients with rectosigmoid carcinoma. However, all patients who have undergone resection for rectal or sigmoid carcinoma should have aggressive CT evaluation including a baseline study at 2-4 months and then follow-up studies at every 6 months for at least 2 years. All new or enlarging masses should have CT-guided biopsies. This approach may prolong survival by detecting early asymptomatic recurrences.

Adult↗
PubMed1986

Pancreaticobronchial fistula. Case report and review of the literature.

Fistulas between the pancreas and bronchial tree are uncommon examples of internal pancreatic fistulas. We describe a case of pancreaticobronchial fistula in which the diagnosis was made by bronchoscopy and biochemical analysis of respiratory secretions. Endoscopic retrograde cholangiopancreatography was confirmatory and guided treatment by internal drainage of the pancreatic duct. Ten other cases were found in the Western literature that emphasize the principles of diagnosis and treatment.

Aged↗
PubMed1985

Muir-Torre syndrome in several members of a family with a variant of the Cancer Family Syndrome.

Distinguishing cutaneous signs which are associated with hereditary cancer-prone syndromes are known as cancer-associated genodermatoses. Muir-Torre syndrome (M-T) is characterized by the occurrence of sebaceous hyperplasia, adenoma and carcinoma, basal cell carcinoma with sebaceous differentiation, and/or keratoacanthoma in association with visceral cancer (often multiple), and improved survival. Family studies of M-T have been either wholly lacking or too incomplete to elucidate hereditary aetiology. We describe the cutaneous phenotype of M-T in an extended kindred with a possible variant of the Cancer Family Syndrome. We emphasize the need for more thorough documentation of family histories and cancer association in this cancer-associated genodermatosis in order to clarify hereditary syndrome identification, and to improve cancer control through employment of cutaneous signs as a beacon for highly targeted forms of visceral cancer.

Adolescent↗
PubMed1985

Esophageal lesions after total laryngectomy.

Clinical and endoscopic evaluation of the post-total laryngectomy patient with dysphagia may be limited by postoperative fibrosis or strictures. The barium esophagogram is a valuable adjunctive tool in further assessing these patients, as both functional and anatomic abnormalities can be evaluated. A 10-year retrospective review yielded 204 patients who had had total laryngectomies for squamous cell carcinoma of the larynx; 85 of these patients had postoperative barium esophagograms. Dysphagia was the chief complaint in 73 of these 85 patients. The studies were reviewed for anatomic abnormalities of the surgically deformed pharynx (neopharynx) and the esophagus distal to it. While most patients (51%) with dysphagia had abnormalities in the neopharynx, 17 (23%) had abnormalities distal to the neopharynx; these included four esophageal carcinomas and 13 benign esophageal strictures. These results emphasize the importance of evaluating the entire esophagus and maintaining a high index of suspicion for distal esophageal disease in the total laryngectomy patient with dysphagia.

Aged↗
PubMed1985

Hypochlorite radioiodination of parathyroid peptides (hPTH1-34, [Tyr43]hPTH44-68).

Parathyroid hormone (PTH) radioimmunoassays have conventionally utilized [125I]bPTH1-84 as a radioligand, but more region-specific PTH assays are now possible with the use of recently available synthetic PTH peptides as standards and radioligands. A radioiodination procedure has been developed that utilizes hypochlorite as an oxidant and that is capable of producing PTH tracers of high specific activity (200 to 250 microCi/micrograms), prolonged stability, and excellent immunologic potency. Radioiodinated hPTH1-34 and [Tyr43]hPTH44-68 produced by hypochlorite iodination techniques can be used to develop sensitive and region-specific PTH assays of use in clinical and research situations.

Chemical Precipitation↗
PubMed1983

Mouse histocompatibility genes: structure and organisation of a Kd gene.

The gene coding for the mouse H-2Kd antigen has been isolated by using a K-locus specific cDNA probe. The complete nucleotide sequence of the gene reveals eight exons separated by seven introns. Transcriptionally important DNA sequences (CCAAT and TATA) precede the first exon. Comparison with other H-2 genes shows extensive homology in exons as well as in introns. Two cDNA clones encoding Kd antigens have been analysed and provide evidence for at least two expressed Kd genes in the DBA/2 mouse. Comparison of the Kd antigen sequence to three other H-2 antigens indicates that gene conversion mechanism(s) act on H-2 genes. Analyses of exon donor and acceptor sites of different H-2 genes and cDNAs show that alternative splicing sites are used by different genes.

Alternative Splicing↗
PubMed1983

Malformations of the atlas vertebra simulating the Jefferson fracture.

Congenital clefts and aplasias of the atlas vertebra, while rare, are often first encountered in the emergency room setting. Thirty-six patients with atlas malformations and 10 with Jefferson fractures were encountered. Sixteen of the patients with congenital malformations showed bilateral atlantoaxial lateral offset, a finding generally considered to be the result of fracture. The diagnosis of these abnormalities is readily made from plain films by noting their characteristic features. Anomalies produce lateral offset of 1-2 mm. Jefferson fractures produce a greater offset (over 3 mm).

Atlanto-Occipital Joint↗
PubMed1983

Transluminal angioplasty of the superior mesenteric artery: an alternative to surgical revascularization.

Percutaneous transluminal angioplasty of stenotic lesions of the superior mesenteric artery was performed eight times in four patients with ischemic bowel syndrome. All patients were either poor surgical risks or had lesions not amenable to surgical correction. One patient also had angioplasty of a stenotic celiac artery. The four patients in this report have had more than 1 year of follow-up. All have had good results. Superior mesenteric artery angioplasty seems to be a nonsurgical alternative for the treatment of atherosclerotic mesenteric ischemia.

Adult↗