Oligosaccharides from human milk block binding and activity of the Escherichia coli heat-stable enterotoxin (STa) in T84 intestinal cells

Enterotoxin-producing Escherichia coli are major causes of pediatric diarrhea in developing countries. The heat-stable enterotoxin of Escherichia coli (STa) causes diarrhea by virtue of its ability to bind to and stimulate intestinal membrane-bound guanylate cyclase, generating cyclic GMP (cGMP). Previous work showed that a fucosylated oligosaccharide fraction of human milk was able to protect suckling mice from the secretory effects of STa, but the mechanism of the protection could not be determined. Oligosaccharide fractions from human milk were tested for their ability to block the biochemical effects of STa in T84 cells, a human colon carcinoma line responsive to the toxin. Total and fucosylated oligosaccharide fractions were found to inhibit STa-stimulated guanylate cyclase activity in T84 cell membranes and cGMP production in intact T84 cells by 60-80%. In addition, the total oligosaccharide fraction and the fucosylated oligosaccharide fraction inhibited 125I-STa binding significantly (17% and 27% inhibition, respectively). These findings demonstrate the protective activity of human milk oligosaccharides against STa in a human-derived cell line and show that the biochemical step blocked by oligosaccharides is STa-mediated stimulation of guanylate cyclase. This represents a novel mechanism by which human milk oligosaccharides protect against diarrhea.     

Multinucleated giant cells in fine-needle aspiration of thyroid nodules: their diagnostic significance.

Multinucleated giant cells (MNGCs) are reported in many thyroid lesions. This study examines whether their quantity and quality can help in the differential diagnosis. All fine-needle aspirations (FNAs) of the thyroid with a "significant" number of MNGCs were reviewed from 1995 -1998. There were 23 cases (<1% of thyroid FNAs): 8 papillary carcinomas (PC), 4 subacute thyroiditis (ST), 3 granulomas, 7 adenomatous goiters (AG), and one Hurthle-cell adenoma (HA). MNGCs with dense cytoplasm were seen exclusively in PC, ST, and granulomas. They had angulated shapes. They were most numerous, largest, and with the highest number of nuclei in ST and granulomas. MNGCs with foamy cytoplasm were seen in AG and HA and 80% of the other cases (PC, ST, and granulomas). In PC, rare MNGCs had intranuclear inclusions and grooves. The accompanying cell population was characteristic of each disease. The quantity and quality of MNGCs in thyroid FNA may be helpful in narrowing the differential diagnosis. Diagn. Cytopathol. 1999;21:307-312.     

Double-knot transscleral suture fixation technique for displaced intraocular lenses

PURPOSE: To describe a simplified new technique for repositioning and attaching a suture to the haptic of a displaced posterior chamber intraocular lens (IOL). METHODS: We describe a double-knot technique for repositioning and transscleral suture fixation of a subluxed posterior chamber IOL after penetrating keratoplasty. Two 10-0 Prolene transscleral sutures on straight needles are passed around the IOL haptic, tied extraocularly, and used to secure the repositioned haptic of the IOL. A second knot ties the transscleral suture in the scleral bed, stabilizing the haptic in the ciliary sulcus. RESULTS: In the case described, the IOL was stable and well positioned 2 months after surgery. CONCLUSION: The double-knot technique for intraocular repositioning and transscleral suture fixation of displaced posterior chamber IOLs reduces the extensive intraocular manipulation and scleral incisions required for IOL exchange and may reduce chronic irritation associated with iris fixation.     

The effects of oxytocin on intracranial pressure

The commonly used vasodilators sodium nitroprusside and nitroglycerine increase the intracranial pressure (ICP). Oxytocin is also a vasodilator although its primary effect is contraction of uterine smooth muscle. We therefore studied the effect of oxytocin on the ICP of cats. Twelve cats were assigned to two equal groups. One group had normal ICP and in the other the ICP was artificially increased by inflating a balloon placed in the extradural space. All of the cats initially received an oxytocin infusion for 15 min. After a period of stabilization, an additional dose of oxytocin was injected as a bolus. Oxytocin administered as an infusion did not change the ICP significantly in any of the cats. Oxytocin administered as a bolus increased the ICP from 27 +/- 4 to 31 +/- 2 mm Hg in the cats with artificially increased ICP. There were no significant changes in the mean blood pressure or heart rate in either group.     

Unusual Hepatic Tumor with Features of Mesenchymal Hamartoma and Congenital Solitary Nonparasitic Cyst

We report a hepatic tumor in an adolescent that does not fit into any of the described categories of liver tumors. The patient presented with hepatomegaly, abdominal pain, and normal liver function test; the tumor was cystic in imaging studies. The resected specimen, result of a partial hepatectomy, measured 21 cm and was multicystic with solid areas. Microscopically, the cysts were lined by a mucous-producing or intestinal-type epithelium, associated with smooth muscle and small mucous-producing glands. The solid component contained fibrous and adipose tissue, smooth muscle and thick-walled vessels. Aneuploidy was demonstrated by flow cytometry. We interpreted the tumor as having features of a mesenchymal hamartoma and congenital solitary nonparasitic cyst. It is conceivable that the lesions originated with small peribiliary glands with dilatation and intestinal metaplasia.     

Continuous positive airway pressure and type 2 diabetes mellitus

Obstructive sleep apnea (OSA) is a sleep disorder, increasingly recognized. It is commonly present in obese persons, treated with continuous positive airway pressure (CPAP), being the gold standard. The disorder has been associated with diabetes mellitus and possibly related to hypoxia per se, increased sympathetic activity, disturbed hypothalamic–pituitary–adrenal axis and increased inflammatory cytokines and leptin, all of which can adversely affect both glucose metabolism and insulin sensitivity. Given this association and the presence of common risk factors, this review assessed the impact of CPAP on diabetes mellitus through various metabolic parameters including HbA1c, nocturnal glucose and insulin resistance, in addition to the effect of CPAP on the prevention of diabetes mellitus. Results have been conflicting; Randomized controlled trials are recommended to allow objective and definite conclusions.