Comprehensive study of the geometry, surface area, membrane reserve potential, and osmoregulation of blood leukocytes

Comprehensive method for examining the morphology and function of leukocytes is based on the comparison of the size and count of cells before and after incubation of different duration in media with low osmolarity. The method helps assess the leukocyte geometry, the reserve potential of the cytoplasmatic and nuclear membranes, the regulatory features and osmotic stability of cells.     

Modeling multimode-input star couplers in polymers

In this paper, we present the first numerical study of highly multimode-input integrated-optic star couplers. Although the design utilizes the physical quantities appropriate for a polymer device, many of the results are applicable to multimode-input star couplers using a wide range of materials. Design parameters explored include the input-port waveguide width, refractive index difference, and insertion angle. The simulation work is done utilizing the beam propagation method. The statistically based scaling parameters for these highly multimode structures are shown to be compatible with the results of an analytical model which is suitable for initial device design     

Nasal polyps in children

The inflammatory nasal polyp is the most common benign or malignant nasal mass seen in children. Nasal polyps in the pediatric population appear to occur as inflammatory responses to bacterial infections. In 33% of the patients with polyps whom we studied, antral choanal polyps were noted, and in 20% of the patients the polyps were unilateral but not antral choanal. In 18% of the patients the polyps were bilateral and in an additional 29% they occurred bilaterally in association with cystic fibrosis. History of an allergy is infrequently associated with nasal polyps; allergies are potentially major contributing factors to nasal polyps only in patients without cystic fibrosis whose nasal polyps are bilateral. Patients with antral choanal polyps are most successfully managed by simultaneous Caldwell-Luc antrostomy and polypectomy. Sixty percent of patients with nasal polyps and cystic fibrosis are adequately managed with a single intranasal polypectomy. Simultaneous sinus surgery and polypectomy should be considered for all patients with recurrent polyps and for all patients with clinical or radiographic evidence of significant sinusitis. Complications, including epistaxis and intranasal synechia, occurred in 3% of the 170 surgical procedures performed.     

The influence of thrombopoietin (TpO) on human erythropoiesis. In vitro studies--clinical implications

beta-Glucuronidase of human or bacterial origin may deconjugate bilirubin diglucuronide, causing pigment gallstones. Intrinsic interference by biliary compounds must be minimized for accurate assay of beta-glucuronidase. We report a modified ion-pair extraction of interfering substances by tetrahexylammonium chloride (THAC) in ethyl acetate in the presence of albumin, and a microtitre plate assay for biliary beta-glucuronidase activity in bile with the substrate p-nitrophenol-glucuronide. Adding albumin improved the recovery of beta-glucuronidase activity to 99.8% (CV 1.9%), and 92.2% of the bilirubin in bile samples was extracted in one step. Competitive inhibition was overcome by increasing the substrate concentration. In endoscopically obtained common duct bile from 44 patients, five different beta-glucuronidase activity peaks were identified, at pH 3.9, 4.8, 5.3, 5.8 and 7.2. The pH profiles were classified into one bacterial pattern and five patterns for presumed human beta-glucuronidase. Of the latter patterns, four displayed dual activity peaks. In a second sample, obtained at follow up in four patients, their original pH profile was maintained. In conclusion, using the modified purification and assay system, we found functionally diverse subcategories of human beta-glucuronidase with respect to activity at variable pH. Our results indicate that several pH optima have to be taken into consideration in order to clarify the role of human biliary beta-glucuronidase in the pathogenesis of pigment gallstones. Bacterial beta-glucuronidase activity was associated with duodenal diverticula (p < 0.05) and common duct stones (p < 0.05).     

Gliogenesis in postnatal rat optic nerve: LC1 + microglia and S100-beta + astrocytes

Lipocortin 1 (LC1) and S100-beta, two Ca(2+)-binding proteins that serve as specific markers for microglia and astrocytes, respectively, have been used to study postnatal gliogenesis in the rat optic nerve. Computerized image analysis was used to quantify and map the stained and unstained glia in transverse sections (10 microns thick) taken 1-2 mm from the chiasm in optic nerves from rat pups at postnatal day 0 (P0), P7, P14, P21, P28, P38 and adults. The number of astrocytes was remarkably constant (100 per section) at all ages. Because the area of the nerve increases 10-fold from P0 to adult, the population density of astrocytes begins al > 5000 mm-2 and drops to 400 mm-2 in the mature nerve; however, because the nerve length increases two-fold, the number of astrocytes doubles over the same period. In contrast, the number of LC1 + cells per section initially is sparse (4 at P0), increases rapidly up to 36 at P21 and levels off at 49 in adults. The microglia population density is relatively stable throughout development (200-300 mm-2) except during the peak of oligodendroblast apoptosis (P21) when it rises to 450 mm-2. Neonatally, LC1 immunoreactivity predominantly labels spherical-ameboid cells; but by P28 they are replaced by mature ramified microglia. The number of unstained cells (putative oligodendrocytes) per section increases from 11 at P0 to a peak of 308 at P21, and declines slightly to 269 in adults. While generally confirming concepts of astrocyte and oligodendrocyte ontogeny from the literature, the present report adds considerable detail regarding microglia, which often have been ignored. Microglia identified by LC1 immunoreactivity comprise 12% of the glia in adult optic nerve near the chiasm.     

Summary measures of the insulin resistance syndrome are adverse among Mexican-American versus non-Hispanic white children: the Corpus Christi Child Heart Study

BACKGROUND: Mexican-American (MA) adults are known to have a greater burden of diabetes and insulin resistance than non-Hispanic white (NHW) people. In this report, we examined data obtained from MA and NHW third-grade children for evidence of a pattern consistent with the insulin resistance syndrome. In addition, we developed two summary measures characterizing insulin resistance syndrome to compare measures of this syndrome among our population. METHODS AND RESULTS: Data regarding fasting insulin, triglycerides, HDL cholesterol, systolic blood pressure, and body mass index (BMI) were available for 403 third-grade children. Median levels of insulin and glucose were significantly higher in MA boys and girls than in NHW boys and girls. Risk factors characterizing insulin resistance, including levels of insulin, triglycerides, systolic blood pressure, HDL cholesterol, and BMI were categorized as above or below the total population median. MA children were more likely than NHW children to have three or more adverse risk factors (55% versus 37%). When risk factors were converted to Z scores, and the five Z scores were summed for each individual, MA boys and girls had higher mean scores than NHW boys and girls (means for boys, 0.65 versus -0.97, P<.0001; girls, 0.52 versus -0.30, P<.04). Principal components analysis was used to create a summary score or index representing the insulin resistance syndrome. This summary score was significantly higher among MA boys and girls than NHW boys and girls (means for boys, 0.34 versus -0.72, P<.0001; girls, 0.35 versus -0.04, P=.056). CONCLUSIONS: Our results support the hypothesis that MA children exhibit a greater degree of the insulin resistance syndrome than NHW children, especially among boys. We conclude that some of the factors responsible for the increased risk of NIDDM seen among MA adults are demonstrable in childhood.     

The role of insulin (INS) and insulin-like growth factor-I (IGF-I) in regulating human erythropoiesis. Studies in vitro under serum-free conditions--comparison to other cytokines and growth factors

The role of insulin (INS), and insulin-like growth factor-I (IGF-I) in the regulation of human erythropoiesis is not completely understood. To address this issue we employed several complementary strategies including: serum free cloning of CD34+ cells, RT-PCR, FACS analysis, and mRNA perturbation with oligodeoxynucleotides (ODN). In a serum-free culture model, both INS and IGF-I enhanced survival of CD34+ cells, but neither of these growth factors stimulated their proliferation. The influence of INS and IGF-I on erythroid colony development was dependent on a combination of growth factors used for stimulating BFU-E growth. When BFU-E growth was optimally stimulated with erythropoietin (EpO) + kit ligand (KL) the large erythroid colonies developed normally even in the absence of INS or IGF-I. However, the addition of both of these growth factors slightly enhanced colony size. On the other hand, if erythroid colonies were stimulated suboptimally with EpO + IL-3 only, INS or IGF-I increased the number of small erythroid bursts by approximately 30%. Both INS and IGF-I activated signal transduction in maturing human erythropoietic cells as determined by phosphorylation of the insulin receptor substrate-2 (IRS-2) protein. We also found by RT-PCR that mRNA coding for INS-R is expressed in FACS sorted CD34+, c-kit-R+ marrow cells, and in cells isolated from BFU-E and CFU-GM colonies. Expression of INS-R protein on these cells was subsequently confirmed by cytofluorometry. In contrast, the receptor for insulin-like growth factor-I (IGF-IR) was not detected on CD34+ cells, and was first easily detectable on more differentiated cells derived from day 6 BFU-E and CFU-GM colonies. We conclude that INS and IGF-I may be survival factors for human CD34+ cells, but are not required during early erythropoiesis. In contrast, both growth factors may play some role at the final stages of erythroid maturation.