[Biomechanical characteristics of human fetal membranes. Preterm fetal membranes are stronger than term fetal membranes]. / Biomécanique de la rupture des membranes fœtales. Les membranes fœtales sont plus résistantes avant terme qu'à terme.

The purpose of this study was to determine the biomechanical characteristics of human fetal membranes (FM) throughout gestation. Biomechanical properties were determined for 115 FM of 23-41 weeks gestation using our previously described methodology. The areas of membrane immediately adjacent to the strongest and weakest tested spots were sampled for histomorphometric analysis. Clinical data on the patients whose FM were examined were also collected. FM less than 28 weeks gestation were associated with higher incidence of abruption and chorioamnionitis. Topographically FM at all gestations had heterogeneous biomechanical characteristics over their surfaces with distinct weak areas. The most premature membranes were the strongest. FM strength represented by rupture force and work to rupture decreased with increasing gestation in both weak and strong regions of FM. This decrease in FM strength was most dramatic at more than 38 weeks gestation. The FM component amnion-chorion sublayers were thinner in the weak areas compared to strong areas. Compared to term FM, preterm FM are stronger but have similar heterogeneous weak and strong areas. Following a gradual increase in FM weakness with increasing gestation, there is a major drop-off at term 38 weeks gestation. The FM weak areas are thinner than the stronger areas. Whether the difference in thickness is enough to account for the strength differences is unknown.

Effect of tamoxifen on 1,2-dimethylhydrazine-HCl-induced colon carcinogenesis in rats.

BACKGROUND: Evidence suggests that steroid hormones may affect the natural history of colon cancer. METHODS: Baseline levels of estrogen receptors, polyamines, and ornithine decarboxylase in colonic mucosa, and blood estradiol were measured in 10 normal Sprague-Dawley outbread female rats. Therefore, 151 rats were fed a 15% fat diet and divided into three groups. Rats in the control group (n = 20) received weekly s.c injections of the 1,2-Dimethylhydrazine-HCl (DMH) vehicle. To induce colon cancer, 131 rats received weekly subcutaneous injections of DMH (20 mg/kg). Of these 131 rats, 65 also ingested 0.5 microgram/g tamoxifen, daily. Half of the rats in each group were sacrificed at 14 weeks, the remainder at 28 weeks. All measurements were repeated at these times and tumor incidence was calculated. RESULTS: The number of rats with tumors was 41% higher (P = .07) in rats treated with DMH vs those treated with tamoxifen and DMH (72.7% vs 51.5%). Tumor cells in both groups had higher levels of polyamines and ornithine decarboxylase activities (P = .03 to P < .001) and lower levels of estrogen receptors (P = .005) to P < .001) compared to adjacent normal colonic mucosa. Estrogen receptors were not detected in the colons of the rats in the control group. No correlations were found between estradiol and estrogen receptors in normal (r = .01, P = .95) or tumor (r = .03, P = .86) cells, or between polyamines or ornithine decarboxylase and estrogen receptors in normal (r = .01 to .14, P = .63 to .95) or tumor (r = .07 to .26, P = .16 to .86) cells. CONCLUSIONS: Tamoxifen reduced the incidence of DMH-induced colon cancer in rats and may thus have chemopreventive effects. Although it was not statistically significant, further studies are justified to continue this line of research.

The Kleihauer-Betke test. Clinical utility, indication, and correlation in patients with placental abruption and cocaine use.

This study examines the indications for performing the Kleihauer-Betke (KB) test and makes recommendations for its use. Results of 523 KB tests performed during 1993 at our hospital (Cleveland, Ohio) are reviewed in conjunction with surgical pathology reports of placental findings, obstetric records, and toxicology results. We conclude that the KB test should be performed following a positive screening test on all Rh negative mothers of Rh positive infants. Additional indications include cases of maternal trauma, unexplained increased maternal alpha-fetoprotein levels, fetal distress with abnormal heart tracings, intrauterine fetal death, and cases of unexplained neonatal anemia. We note that the KB test should not be performed to detect suspected placental abruption.

Somatostatin-producing neuroendocrine tumor of the ampulla (ampullary somatostatinoma). Evidence of prosomatostatin production.

Two cases of somatostatin-producing ampullary neuroendocrine tumors (somatostatinoma) are reported. The authors have characterized their immunoreactivity using antibodies specific for the amino- and carboxyl-terminal portions of prosomatostatin, the precursor of somatostatin in the normal synthetic pathway. Cytoplasmic staining was found using each of these two antibodies in the tumor cells of both ampullary somatostatinomas as well as in the cytoplasm of cells in the hypothalamus, crypt cells of the duodenal mucosa, mucosal cells of the biliary tract, D cells of the pancreatic islets, and parafollicular cells of fetal thyroid. These studies suggest that the synthesis of somatostatin in ampullary somatostatinomas occurs through the normal pathway from the precursor prosomatostatin.

Role of the transitional mucosa of the colon in differentiating primary adenocarcinoma from carcinomas metastatic to the colon. An immunohistochemical study.

Differentiation between primary colonic adenocarcinoma arising in flat mucosa and carcinoma metastatic to the colon is often difficult. Examination of the mucosa adjacent to the tumor, the so-called transitional mucosa (TM), may be helpful. The morphologic, ultrastructural, and histochemical characteristics of the TM have been reported previously in detail. In this study the morphologic and immunohistochemical characteristics of the TM have been compared in 18 cases of primary colonic adenocarcinoma and 13 cases of metastasis to the colon. Five immunophenotypic markers were used: carcinoembryonic antigen (CEA), Lewis (x) and (y) blood group antigens, ras oncogene p21, and tumor-associated glycoprotein (TAG-72). Neoplastic transformation of colonic epithelium is associated with altered expression of these antigens. The morphologic and immunohistochemical profile of the TM was similar in both primary colonic adenocarcinomas and metastases to the colon. In some cases the TM adjacent to colonic metastases stained with one or more antibodies while the metastatic tumor was negative. Therefore, in cases where differentiation between primary colonic adenocarcinoma arising in flat mucosa and metastasis is difficult, the use of these reagents, particularly CEA, TAG-72, or ras oncogene p21, may be helpful. The similar immunohistochemical staining pattern of the TM in both primary and metastatic colon lesions supports a reactive, non-neoplastic origin of the TM. Furthermore, expression of these antigens is not limited to neoplastic epithelial cells.

The intrathyroidal hyperfunctioning parathyroid gland.

Six cases of primary hyperparathyroidism due to hyperfunctioning intrathyroidal parathyroid glands are reported. In five cases, hyperparathyroidism was due to an intrathyroidal parathyroid adenoma; in the sixth case, hyperparathyroidism resulted from an intrathyroidal parathyroid carcinoma. All five patients with adenoma were female with ages ranging from 40 to 70 yr. The patient with carcinoma was a 55-yr-old male. In all five patients with intrathyroidal parathyroid adenoma, thyroidectomy was performed when an abnormal parathyroid gland could not be located in the neck during surgery for hyperparathyroidism. The patient with intrathyroidal parathyroid carcinoma presented with hypercalcemia and a palpable right thyroid mass. The differential diagnosis of intrathyroidal parathyroid adenoma includes thyroid follicular adenoma. In some cases, the possibility of medullary carcinoma of thyroid might also be considered. Immunocytochemical staining for parathormone (PTH), thyroglobulin, and calcitonin is valuable in establishing the correct diagnosis.

Extrapancreatic gastrinoma with pancreatic islet cell hyperplasia.

A case of Zollinger-Ellison syndrome was associated with diffuse islet cell hyperplasia of the pancreas and extrapancreatic gastrinoma. At autopsy, the patient, who had well-documented Zollinger-Ellison syndrome, was found to have gastrinoma in parapancreatic lymph nodes with islet cell hyperplasia but no evidence of pancreatic neoplasm. Possible explanations include the production of a trophic factor by the extrapancreatic gastrinoma, leading to islet cell hyperplasia, or metastasis from a microscopic nodule of gastrin cells that, despite having a "hyperplastic" appearance, exhibited malignant potential.

Accuracy of and reasons for frozen sections: a correlative, retrospective study.

Previous studies on the accuracy of frozen sections (FS) were not based on the reasons for which the FS was performed. By omitting this important information, those studies reported FS accuracy of 94% to 97.4%. The current study analyzes the accuracy of FS diagnoses based on the reasons for which they were conducted. Of 482 specimens examined by FS in 1986, 41 were performed for evaluation of section margins of tumors, 29 for identification of unknown tissue, and 43 for detection of lymph node metastases. All 113 of these examinations proved to be 100% accurate. The remaining 369 FS were performed for diagnosis of an unknown pathologic process. Of these, 83.47% were precisely diagnosed; in 10.30%, the pathologic process was correctly, but not precisely, diagnosed; in 3.79%, the diagnosis was deferred; and the remaining 2.44% were incorrectly diagnosed (with no harmful consequences to the patients). By eliminating the cases of deferred diagnoses, the accuracy rate increased to 86.76%. Therefore, we suggest that the pathologist and the surgeon should not draw any conclusion from an inconclusive interpretation of FS and should proceed as though an FS had not been performed. When combining results of "precise diagnoses" with those of "correct pathologic process," the overall accuracy rate increased to 97%. The investigators conclude that FS should be used for a general diagnosis of a pathologic process rather than for an exact or precise diagnosis. Finally, we suggest that a similar survey of FS be periodically performed in every pathology department as part of its quality assurance program.