De novo induction of island capsule flap by using two silastic sheets: Part 1. Generation

A new experimental model for de novo generation of an axial pattern island flap has been designed in a rat model. The purpose of this study was to make a sufficient vascular carrier, as an island capsule flap, with only vascular pedicles and addition of collagen fibers induced by foreign-body reaction. The femoral arteriovenous bundle was isolated and sandwiched between two 2.5 x 1.5 cm Silastic sheets. Eight weeks later, as a delay procedure, femoral vessels were ligated at the distal end of the Silastic sheets and the four margins of the sheets were divided except for the vascular pedicle. This capsule flap was raised as a secondary island flap connected only by its vascular pedicle, then it was sutured back in place. Ten days after the delay procedure, the upper Silastic sheet was removed and a full-thickness skin graft was performed on the capsular island flap. Animals were killed at 80 days. A total of 40 axial pattern capsulocutaneous flaps from 20 Sprague-Dawley rats were successfully achieved. Pathologic study revealed neovascularization, and abundantly impregnated vascular structures near the pedicle were observed with randomly developed collagen fibers. The skin graft took 100 percent on this newly formed capsular flap; therefore, the capsule structure was able to survive on its own and support skin grafts. This experiment, by using an isolated femoral artery and vein as the main pedicle, led to the formation of a capsule flap through a normal foreign body reaction between two Silastic sheet implants. This new flap can be used as a reliable vascular carrier for various needs with minimal donor morbidity.

Preparation and characterization of Japanese encephalitis virus vaccine loaded poly(L-lactide-co-glycolide) microspheres for oral immunization

Japanese encephalitis virus (JEV) vaccine loaded biodegradable poly(L-lactide-co-glycolide) (PLGA) microspheres (MSs) were prepared by W/O/W solvent evaporation method to study the possibility for oral vaccination. The influence of several preparation parameters as stirring rate, types and concentration of emulsifier, PLGA concentration, etc. has been observed on size, size distribution and biodegradation. The mean MSs size decreased when the agitation speed and the concentration of emulsifier were increased, and when the PLGA concentration was decreased. The surface morphology of porous and nonporous JEV vaccine loaded PLGA MSs was prepared from polyvinylalcohol and sodium dodecyl sulfate as used emulsifiers, respectively. From the assay of lactic acid and scanning electron microscope observation, it can be suggested that the rate of biodegradation of nonporous MSs was slower than that of porous surface morphology due to lower the surface area. Mechanisms of the formation of porous and nonporous surface by different types of emulsifier, and the biodegradation of MSs have been proposed. Also, the size and size distribution of JEV vaccine loaded PLGA MSs were discussed to apply oral vaccination through the Peyer's patches across the gastrointestinal tract.

Release of renal dipeptidase from rabbit renal proximal tubules and its inhibition by gentamicin

Effects of several drugs on rabbit renal proximal tubules were examined for the applicability of renal dipeptidase (RDPase, EC 3. 4. 13. 11) release as a model system to study nephrotoxicity. The proximal tubule prepared by the method of Taub (1990) released RDPase spontaneously in the control experiment which was confirmed by Western blotting. RDPase was also released from cisplatin, lipopolysaccharide (LPS), and indomethacin-treated tubules. Gentamicin inhibited RDPase release in a concentration-dependent manner. This RDPase release system may not be a general model to screen nephrotoxicity but could be a useful source of RDPase purification in a simple and inexpensive way.

Optimization of urinary FDG excretion during PET imaging

Accumulation of fluorodeoxyglucose (FDG) activity in the urine interferes with the visualization of pelvic and, sometimes, abdominal abnormalities. Although this is a major problem, there are few data on the physiological variables affecting FDG urinary excretion that are critical to minimizing urinary FDG interference during PET imaging.

METHODS

The excretion of FDG in urine was determined during 90 min in four groups of rats (n = 24) under the following conditions: normal, hydrated, hydrochlorothiazide treated and phlorizin treated. FDG clearance rates were measured in both normal and phlorizin-treated animals and compared with the glomeruler filtration rate measured with 99mTc-diethylenetriamine pentaacetic acid. We measured FDG excretion in 10 patients who had no known renal disease and were undergoing PET scanning (divided into two groups: hydrated and dehydrated) to relate the animal data to humans.

RESULTS

The hydrated and phlorizin-treated animals had the highest excretion of FDG (39.68+/-5.00 % injected dose (%ID) and 45.64+/-9.77 %ID, respectively). Animals given the hydrochlorothiazide had the highest urinary volume, but the percentage excreted was comparable with the normal rats. Measurement of the clearance of FDG in animals before and after the administration of phlorizin determined the amount of FDG reabsorbed in the proximal tubules to be 56%+/-9.15%. The hydrated patients had a higher excretion of FDG than dehydrated patients (16.98+/-1.99 %ID versus 14.27+/-1.00 %ID, P < 0.021), and the volume of urine voided was significantly higher (P < 0.020).

CONCLUSION

Hydrochlorothiazide increases urine volume without enhancing FDG excretion. The hydration of patients before PET scanning may lead to more FDG reaching the bladder. Reduction of bladder activity by more frequent voiding facilitated by increased urine volume in hydrated patients may be offset by increased delivery of FDG to the bladder. A preferable means of increasing urinary volume without increasing delivery of FDG to the bladder may be the use of a diuretic.

Nutritional status of Korean peritoneal dialysis patients

OBJECTIVES

To assess the nutritional status of Korean peritoneal dialysis (PD) patients and to compare with data from Western literature, and to elucidate independent factors determining nutritional status and death.

DESIGN

Cross-sectional single-center study.

SETTING

Kidney Center, Soon Chun Hyang University Hospital.

MATERIALS

Ninety-eight CAPD patients were included. Of these, 54 patients were male, 32 patients were diabetic, mean age was 47.9+/-13.1 years, and mean duration of CAPD was 22.3+/-21.6 months. The patients were followed until death, transfer to hemodialysis (HD) or other units, transplantation, or until 3 years had elapsed after the first evaluation.

METHODS

Nutritional status was assessed by subjective global assessment (SGA), biochemical and anthropometric measurements, fat-free edema-free (FFEF) body mass by creatinine (Cr) kinetics, protein equivalent of total nitrogen appearance (PNA), and urea kinetic studies.

RESULTS

By SGA score, 53.1% of patients were classified as normal, 44.9% with mild-to-moderate malnutrition, and 2% with severe malnutrition. Patients with malnutrition were significantly older and had higher peritonitis rates, lower serum albumin (Alb), blood urea nitrogen (BUN), serum Cr, FFEF body mass, mid arm muscle circumference, and PNA (p < 0.05). On stepwise multiple regression analysis, the SGA score was negatively correlated with age and peritonitis rate (p < 0.01). At the end of the 3-year follow-up period, 11 patients were still on CAPD, 26 had died, 51 had transferred to HD and 5 to other units, 3 patients had been transplanted, and 2 patients were lost to follow-up. Patients who died during follow-up were older and had higher peritonitis rates and lower total serum protein, Alb, Cr, and FFEF body mass when compared to those who survived (p < 0.05). Independent predictors of death were age, peritonitis rate, and serum Alb (p < 0.01).

CONCLUSION

Malnutrition was as common in Korean PD patients as reported in the Western literature. Our data suggests that, to prevent malnutrition and early death, it is important to reduce the peritonitis rate, to improve protein intake, and to prescribe an adequate dose of peritoneal dialysis.

Leukotriene D4 inhibits Na+ uptake through cAMP and PLC pathways in primary cultured renal proximal tubular cells

Leukotriene D4 (LTD4) is one of the slow-reacting substances of anaphylaxis and is reported to have a diverse response including the mediation of glomerular nephritis. However, little is known about the functions of LTD4 and its mechanisms of action in primary cultured rabbit renal proximal tubular cells (PTCs). The purpose of this study is to investigate the effect of LTD4 on Na+ uptake and its related signal transduction pathways in PTCs. LTD4 (>10(-9) M) significantly inhibited the Na+ uptake after 15 min (in nmol/mg protein: controls 431.7+/-11.4 vs. LTD4 (10(-9) M) 355.0+/-23.6; p<0. 05); and its effect was blocked by MK-571 (10(-6) M), a leukotriene receptor antagonist, in PTCs. Preincubation with cilastatin, a renal dipeptidase inhibitor, and polyclonal antibody against renal dipeptidase potentiated the inhibitory effect of LTD4 on Na+ uptake. SQ 22536 (10(-6) M), an adenylate cyclase inhibitor, and the myristoylated protein kinase A inhibitor amide 14-22 (PKI; 10(-5) M) blocked the effect of LTD4 on Na+ uptake (in nmol/mg protein: LTD4 349.9+/-18.5 vs. SQ 22536+LTD4 476.5+/-22.0 and PKI+LTD4 440.3+/-19. 3; p<0.05), and LTD4 induced an increase in cyclic adenosine monophosphate (cAMP), suggesting the involvement of cAMP in the inhibition of Na+ uptake. In addition, U 73122 (10(-6) M) and neomycin (10(-4) M), phospholipase C (PLC) inhibitors, W-7 (10(-4) M), a calmodulin antagonist, and bisindolylmaleimide I, a protein kinase C (PKC) inhibitor, blocked the LTD4-induced inhibition of Na+ uptake, strongly suggesting involvement of the PLC-PKC signal pathways in the effect of LTD4. LTD4 significantly increased [Ca2]i by 49+/-7% as compared with baseline. TMB-8 (10(-5) M) and BAPTA/AM (10(-5) M), intracellular calcium mobilization blockers, completely blocked the LTD4-induced inhibition of Na+ uptake (in nmol/mg protein: LTD4 347.6+/-19.0 vs. TMB-8+LTD4 436.4+/-22.3 and BAPTA/AM+LTD4 419.9+/-14.3; p<0.05); however, EGTA (1 mM), a calcium chelator, partially blocked the LTD4-induced inhibition of Na+ uptake. In conclusion, LTD4-induced inhibition of Na+ uptake may be involved in both cAMP and PLC-PKC signal pathways in PTCs. In addition, Ca2+, which comes from the intracellular Ca2+ mobilization, is primarily responsible for the LTD4-induced inhibition of Na+ uptake.

Simultaneous reconstruction of the Achilles tendon and soft-tissue defect using only a latissimus dorsi muscle free flap

The combined loss of the Achilles tendon and the overlying soft tissue in the young ambulant patient with expectations of a normal life is a challenging problem. These patients need not only soft tissue but also dynamic and functional reconstruction. Four cases of major defects of the Achilles tendon and overlying soft tissue after trauma are presented. In each case, the tendon and the overlying soft tissues were reconstructed using only a latissimus dorsi muscle free flap and overlying split-thickness skin graft. In conventional methods, evolved in the reconstruction of the Achilles tendon and soft tissue, the size of the defect was a limit. However, this technique can be used to reconstruct an extensive defect, including distal calf muscle to the plantar metatarsal area. In one case, the flap was harvested in a myocutaneous unit, and the skin portion was deepithelialized for the coverage and enough padding on the bony exposure area in reverse position. The purpose of the present study was to reevaluate the potential of denervated muscle flap for a force-bearing conduit as an alternative reconstructive method of the Achilles tendon. The denervated latissimus dorsi muscle in this study eventually experienced the process of atrophy and fibrosis but maintained its original length. Although there remained some atrophic muscle fibers, a fibrosis of the muscle fibers formed a tendon-like fibrous band, and so the action of the posterior calf muscle could be transmitted through the tendon-like fibrotic change of the denervated latissimus dorsi muscle. The advantages of this technique are that (1) it is a single procedure, (2) it is adaptable to a wide range of defect sizes, (3) it allows faster wound healing supported by well-vascularized tissues, (4) it produces satisfactory function of the ankle joint and a padding effect, and (5) it produces good contour of the posterior calf to the sole and an acceptable donor-site morbidity.

Expression of ICAM-1 on conjunctival epithelium and ECP in tears and serum from children with allergic conjunctivitis

BACKGROUND

Conjunctival eosinophilia may be considered to be an indicator of conjunctival allergic disease. The absence of eosinophils on conjunctival scraping, however, cannot rule out the diagnosis of allergic conjunctivitis because eosinophil infiltration may be deeper in conjunctival tissue. Eosinophil cationic protein (ECP) is a toxic product secreted by activated eosinophil as a marker of eosinophil activation. Eosinophil cationic protein concentrations in body fluids correlate with the severity of some allergic diseases. ICAM-1 promotes adhesion of leukocytes to epithelium, endothelium, and upregulates inflammation. Expression of adhesion can be modified by many extracellular and intracellular variables such as proinflammatory cytokines, extracellular matrix proteins, and viral infection.

OBJECTIVE

We investigated whether local eosinophils are only activated in conjunctival epithelium or circulating activated eosinophils are involved in peripheral blood during allergic reaction of the eye. We also demonstrated the possible expression of ICAM-1 on epithelial cells from conjunctival scraping and compared them with soluble ICAM-1 values of serum and tears in children with allergic conjunctivitis and healthy children.

METHODS

Seventeen subjects were selected on the basis of clinical manifestations, history, skin prick test, and total serum IgE. A microcapillary tube was used to collect the tears from the inner canthus. Conjunctival epithelia were obtained by scraping the upper tarsal conjunctiva. The level of ECP was measured by the CAP system, soluble ICAM-1 was measured by ELISA, and ICAM-1 on conjunctival epithelial cells were expressed by the avidine-biotin peroxide complex procedure.

RESULTS

Serum IgE and the eosinophil count were increased in 10 out of 17 patients, positive skin prick tests were positive in 11 patients (Dermatophagoides pternyssinus; 9, Dermatophagoides farinae: 8), and eosinophilia in conjunctival epithelium was in 11 patients (4 patients: >3/HPF, 7 patients: 1-3/HPF). The ECP levels in tears were significantly increased in the patient group (12.0+/-8.0 versus 3.9+/-3.8 microg/mL, P = .01), but not in serum (52.5+/-43.1 versus 28.3+/-25.9 microg/mL). There is significant correlation between the eosinophil count in peripheral blood and on conjunctival epithelium (P = .007, r = .62; n = 25). The ICAM-1 expression score on conjunctival epithelial cells was significantly different between the patient group and controls (patient group: 1.77+/-1.25 versus control: 0.13+/-0.35 ng/mL, P = .002). There was a significant correlation between ICAM-1 expression on conjunctival epithelial cells and the ECP levels of tears (P = .01, r = .58; n = 25). Soluble ICAM-1 levels in serum and tears showed no significant difference between the patient group and controls, and also, there was no correlation between sICAM-1 levels in the serum and tears.

CONCLUSION

Eosinophil cationic protein in tears and ICAM-1 expression scores on conjunctival epithelium showed a significant difference between children with allergic conjunctivitis and the healthy controls, but circulating ECP and sICAM-1 in serum were not significantly different between the two groups. These results may suggest that ICAM-1 is locally upregulated in inflammation, mediating eosinophil activation and migration to conjunctival epithelium, but is not involved as inflammatory mediators in peripheral blood during allergic response in children with allergic conjunctivitis.

Analysis of induced sputum to examine the effects of inhaled corticosteroid on airway inflammation in children with asthma

BACKGROUND

Analysis of induced sputum can be performed safely in children with asthma and is useful for both cellular and biochemical markers of inflammation. Glucocorticosteroid inhalation has become the first line therapy for chronic asthma by suppressing airway inflammation, which produces the decrease of bronchial hyperreactivity and reduces the number of eosinophil in bronchial submucosa.

OBJECTIVE

To determine the characteristics of the inflammatory cells and their markers in sputum and to examine the pharmacokinetic effects of glucocorticoid within 3 hours after inhalation therapy on FEV1 and sputum inflammatory indices in children with clinically defined chronic asthma.

METHODS

Thirty subjects with asthma included 14 current symptomatic asthmatics and 14 normal controls inhaled 4.5% hypertonic saline for 10 minutes by nebulizer. The expectorated sputum were collected from all asthmatics before and 3 hours after corticosteroid inhalation for children with asthma and were reduced by dithiotreitol. Total cell counts and differentials were determined. ECP was measured by CAP system. Interleukin-5, GM-CSF and albumin were measured by double sandwich ELISA.

RESULTS

The mean eosinophil percentage and ECP in induced sputum of asthmatics were significantly higher than that of controls. The induced sputum samples obtained after glucocorticoid inhalation showed a significant reduction in mean eosinophil percentage, but FEV1, IL-5, GM-CSF, albumin, and ECP values were not significantly decreased.

CONCLUSION

The present results in induced sputum may be interpreted to reflect direct steroid action on airways and lack of effect on bone marrow effectors at 3 hours after glucocorticoid inhalation.

Interaction of fibroblasts on polycarbonate membrane surfaces with different micropore sizes and hydrophilicity

Surface topography appears to be an important but often neglected factor in implant performance. In this study, fibroblasts were cultured on a range of porous polycarbonate (PC) membranes with well defined surface topography (track-etched micropores, 0.2-8.0 microm in diameter) and wettability gradients. The wettability gradient on the PC membrane surfaces was produced by treating the surfaces with corona from a knife-type electrode whose power increased gradually along the sample length. The PC membrane surfaces were characterized by scanning electron microscopy (SEM) and the water contact angle measurement. Fibroblasts were cultured on the corona-treated PC membrane surfaces with different micropore sizes for 1 and 2 days. The cells attached on the membrane surfaces were examined by SEM and the cell density on the surfaces was estimated by counting the number of attached cells along the wettability gradient. It was observed that the cells were adhered and grew more on the hydrophilic positions of the membrane surfaces than the more hydrophobic ones, regardless of micropore size. It was also observed that cell adhesion and growth decreased gradually with increasing micropore size of the membrane surfaces. It seems that the cell adhesion and growth were progressively inhibited as the membrane surfaces had micropores with increasing size, probably due to surface discontinuities produced by tract-etched pores. On the membrane surfaces with smaller micropore sizes, the cells seemed to override these surface discontinuities.

Environmental factors and nutritional utilization patterns affect niche overlap indices between Aspergillus ochraceus and other spoilage fungi

The total number, and the type of C source utilized in common by an ochratoxin producing strain of Aspergillus ochraceus and six other spoilage fungi varied with the range used (95, Biolog GN plates, or 18 major C sources found in maize). The niche size and niche overlap index (NOI) were markedly influenced by water availability (water activity, aw) and temperature. With freely available water (0.995 aw) there was ecological similarity between A. ochraceus, A. alternata, A. candidus and A. flavus, all exploiting the same sources at both 18 and 30 degrees C. However, under water stress, A. ochraceus had a low NOI compared with A. niger, A. flavus and A. candidus, and Eurotium spp., suggesting that there was very little niche overlap in utilization of different C sources. The NOIs were not directly related to growth rates. Niche overlap between species was shown to be in a state of flux and significantly influenced by environmental factors. This may have important implications in understanding ecological interactions, and dominance by species in a community, and for pre-emptive exclusion of specific species.

Chitin synthase II inhibitory activity of ursolic acid, isolated from Crataegus pinnatifida

Two triterpenoid compounds, ursolic acid and uvaol, were isolated from Crataegus pinnatifida Bunge leaves. Ursolic acid inhibits chitin synthase II from S. cerevisiae with an IC50 value of 0.84 microgram/ml and the inhibition appears to be selective for chitin synthase II, whereas uvaol has no inhibitory activity up to 280 micrograms/ml. Oleanolic acid, alpha-hederin hydrate, and betulic acid inhibited the chitin synthase II activity under the same conditions with an IC50 of 5.6, 64.3, and 98.7 micrograms/ml, respectively.

Platelet and cell interactions on gold sputter-deposited polymeric surfaces

Surface treatment as gold sputter-deposited treatment onto various polymeric surfaces has been investigated to improve the cell-, tissue- and blood-compatibility. Surface treated samples were characterized by measurement of contact angle goniometer and electron spectroscopy for chemical analysis (ESCA). The contact angles on the gold-coated polymeric surfaces decreased from 95-65 degrees to around 50 degrees, i.e., increased hydrophilicity due to incorporation of gold thin layer. From the results of ESCA analysis of the modified polymeric surfaces, surface modification by the gold-sputter method was successfully performed. Morphology of the adhered platelets on the gold-coated polymeric surfaces showed lesser activating than control, and the number of adhered platelets surface modified samples decreased with decreasing water contact angle. Fibroblast cell adhesion and growth on the gold-coated polymeric surfaces were more active than those of control. It seems that surface wettability and surface chemistry of gold play important roles for platelet adhesion and cell adhesion, spreading and growth.

Perfusion impairments in infantile autism on technetium-99m ethyl cysteinate dimer brain single-photon emission tomography: comparison with findings on magnetic resonance imaging

The neuro-anatomical substrate of autism has been the subject of detailed investigation. Because previous studies have not demonstrated consistent and specific neuro-imaging findings in autism and most such studies have been performed in adults and school-aged children, we performed a retrospective review in young children in search of common functional and anatomical abnormalities with brain single-photon emission tomography (SPET) using technetium-99m ethyl cysteinate dimer (ECD) and correlative magnetic resonance imaging (MRI). The patient population was composed of 23 children aged 28-92 months (mean: 54 months) who met the diagnostic criteria of autism as defined in the DSM-IV and CARS. Brain SPET was performed after intravenous injection of 185-370 MBq of 99mTc-ECD using a brain-dedicated annular crystal gamma camera. MRI was performed in all patients, including T1, T2 axial and T1 sagittal sequences. SPET data were assessed visually. Twenty patients had abnormal SPET scans revealing focal areas of decreased perfusion. Decreased perfusion of the cerebellar hemisphere (20/23), thalami (19/23), basal ganglia (5/23) and posterior parietal (10/23) and temporal (7/23) areas were noted on brain SPET. By contrast all patients had normal MRI findings without evidence of abnormalities of the cerebellar vermis, cerebellar hemisphere, thalami, basal ganglia or parietotemporal cortex. In conclusion, extensive perfusion impairments involving the cerebellum, thalami and parietal cortex were found in this study. SPET may be more sensitive in reflecting the pathophysiology of autism than MRI. However, further studies are necessary to determine the significance of thalamic and parietal perfusion impairment in autism.

Sequential effects of high glucose on mesangial cell transforming growth factor-beta 1 and fibronectin synthesis

BACKGROUND

Transforming growth factor (TGF)-beta is recognized as the final common mediator of the principal lesions of diabetic nephropathy such as renal hypertrophy and mesangial expansion. To gain better understanding of the temporal relationships between high glucose (HG) and mesangial cell (MC) TGF-beta 1 synthesis and between TGF-beta 1 and extracellular matrix (ECM) synthesis, the present study examined early and sequential effects of HG on TGF-beta 1 and fibronectin (FN) mRNA expression and protein synthesis.

METHODS

Confluent primary rat MC was stimulated with 5.6 (control) or 30 (high) mM glucose after synchronizing the growth by incubation with serum-free media for 48 hours.

RESULTS

Mesangial cell TGF-beta 1 mRNA expression increased significantly in six hours and continued to increase until 48 hours in response to HG. The level of TGF-beta 1 mRNA was 1.5-fold higher than that of control glucose at six hours and 1.8-fold at 48 hours. TGF-beta activity in heat-activated conditioned media under HG increased 1.5- and 1.6-fold at 24 and 48 hours, respectively, compared to control glucose. FN mRNA increased significantly at 24 and 48 hours and 1.4-fold that of control glucose at both time points. FN protein also increased 1.5-fold that of control glucose at 48 hours. Anti-TGF-beta antibody completely abolished HG-induced FN synthesis.

CONCLUSIONS

The present finding demonstrate that HG stimulates TGF-beta 1 very early and prior to FN production and that HG-induced FN production is mediated by TGF-beta. This finding is consistent with the view that TGF-beta mediates increased ECM accumulation by MC under high glucose conditions.

Determination of 17 beta-estradiol and its metabolites in sewage effluent by solid-phase extraction and gas chromatography/mass spectrometry

The paper describes a simple and quantitative method for monitoring non-conjugated 17 beta-estradiol (E2) and its metabolites estrone (E1) and estriol (E3) as environmental contaminants in municipal sewage effluents. Estrogens were preconcentrated and cleaned up by solid-phase extraction using a reversed-phase C18 cartridge. They were derivatized with pentafluoropropionic acid anhydride, and the products were analyzed by gas chromatography/mass spectrometry. Recoveries from spiked distilled water and sewage were better than 87% at fortification levels of 100 and 20 ng/L. For a 1 L sewage sample and a concentration factor of 5000, detection limits were 5 ng/L for E1 and E2 and 10 ng/L for E3. In a brief survey of Canadian wastewater, these estrogens were detected in many raw sewage and effluent samples at concentrations ranging from 6 to 109 ng/L for E1, from < 5 to 15 ng/L for E2, and from < 10 to 250 ng/L for E3.

Interaction of Different Types of Cells on Polymer Surfaces with Wettability Gradient

Gradient surfaces whose properties are changed gradually along the sample length are of particular interest for basic studies of the interaction between biological species and surfaces since the effect of a selected property can be examined in a single experiment on one surface. We prepared a wettability gradient on low density polyethylene (PE) sheets by treating them in air with the corona from a knife-type electrode whose power increases gradually along the sample length. The PE surfaces oxidized gradually with the increasing corona power, and the wettability gradient was created on the surfaces as evidenced by the measurement of water contact angles, Fourier transform infrared spectroscopy in the attenuated total reflectance mode, and electron spectroscopy for chemical analysis. The wettability gradient surfaces prepared were used to investigate the interaction of different types of cells (Chinese hamster ovary, fibroblast, and endothelial cells) as well as serum proteins in terms of the surface hydrophilicity/hydrophobicity of polymeric materials. The cells adhered and grown on the gradient surface along the sample length were counted and observed by scanning electron microscopy. It was observed that the cells were adhered, spread, and grown more onto the positions with moderate hydrophilicity of the wettability gradient surface than onto the more hydrophobic or hydrophilic positions. The maximum adhesion and growth of the cells appeared at around water contact angles of 55 degrees, regardless of the cell types used. This result seems closely related to the serum protein adsorption on the surfaces; the serum proteins were also adsorbed more onto the positions with moderate hydrophilicity of the wettability gradient surface. Copyright 1998 Academic Press.

Platelet adhesion on the gradient surfaces grafted with phospholipid polymer

We have synthesized omega-methacryloyloxyalkyl phosphorylcholine (MAPC) polymers as new blood-compatible materials, with attention to the surface structure of the biomembrane and investigated their blood compatibility. The blood compatibility observed on the MAPC polymers is due to their strong affinity to phospholipids. When the blood comes in contact with the MAPC polymer, phospholipids in the plasma preferentially adsorb on the surface, compared with the plasma proteins or cells. The adsorbed phospholipids construct a biomembrane-like structure on the MAPC polymer surface. The MAPC polymers then have an excellent blood compatibility. In this study, we prepared a gradient poly(MAPC)-grafted polyethylene (PE) surface using a corona discharge treatment method to clarify the effect of the chemical structure of the MAPC unit on the blood compatibility of the MAPC polymers. The surface composition of MAPC and the hydrophilicity on the poly(MAPC)-grafted PE surface were determined by X-ray photoelectron spectroscopic (XPS) analysis and contact angle measurement with water, respectively. The phosphorus/carbon (P/C) ratio determined by the XPS analysis increased, but the water contact angle decreased with increasing corona irradiation energy. These results indicated that the surface density of the MAPC unit was increased. More than 2.5 cm from the starting point of the corona irradiation, the P/C ratio and water contact angle of the surface achieved a constant level. Thus, the surface was completely covered with the grafted poly(MAPC) chain. The effect of the methylene chain length of the MAPC unit on surface properties was also observed. The phospholipid polar group of the MAPC unit was effectively exposed on the surface as the chain length became longer. Moreover, the hydrophobicity of the surface was increased with the increase in the methylene chain length of the MAPC unit. The number of platelets adhering to the poly(MAPC)-grafted PE surface was reduced from the same point where the P/C ratio became constant.

Modeling the physiological responses of anuran R3 ganglion cells

Teeters and Arbib (Bio Cybernet 1991;64:197-207) presented a model of the anuran retina which qualitatively accounts for some of the characteristic response properties used to distinguish ganglion cell type in anurans. Teeters et al. (Vis Res 1993;33:2361-2379) tested the model's ability to reproduce data of Ewert and Hock (Exp Brain Res 1972;16:41-59) relating toad R2, R3 and R4 ganglion cell responses to moving worm, antiworm and square-shaped stimuli of various edge lengths for stimulus shape and size dependency. In this paper we provide an exhaustive analysis of the performance of the modeled R3 cells with respect to most of the known qualitative and quantitative physiological properties of natural R3 ganglion cells. We also introduce several relevant predictions of the model relating different responses of R3 cells under the effect of changes in different model components. In some cases the predictions have been tested in neurophysiological experiments.

Anticholinesterase induces nicotinic receptor modulation

The effects of carbamate anticholinesterases, pyridostigmine and physostigmine, on the function of the nicotinic receptor (nAChR) in TE671 cells was studied, precluding their inhibition of acetylcholine hydrolysis by carbachol usage. In radioassay, the simultaneous application of carbachol and carbamates dose-dependently decreased carbachol-induced 22Na+ influx, compared with carbachol activation alone. Increasing cell preincubation in the presence of carbamates, however, potentiated influx at low concentrations in a time-dependent manner. This facilitating effect of carbamates, even at high concentrations, was significantly increased by washing out these drugs and was blocked by pretreatment with diisopropylfluorophosphate. Similar results were also obtained in whole-cell patch-clamp study. There were insignificant changes in desensitization properties during facilitation. It is thus supposed that facilitation cannot be explained by the inhibition of acetylcholine hydrolysis. These results support a previous hypothesis that acetylcholinesterase might modulate nAChR by an unknown mechanism. In addition, the clinical effects of carbamates may be partly attributed to this facilitation.

Platelet adhesion onto wettability gradient surfaces in the absence and presence of plasma proteins

A wettability gradient was prepared on lowdensity polyethylene (PE) sheets by treating them in air with a corona from a knife-type electrode the power of which increased gradually along the sample length. The PE surfaces oxidized gradually with the increasing corona power and a wettability gradient was created on the surfaces, as evidenced by the measurement of water contact angles, Fourier transform infrared spectroscopy in the attenuated total reflectance mode, and electron spectroscopy for chemical analysis. The wettability gradient surfaces prepared were used to investigate the adhesion behavior of platelets in the absence and presence of plasma proteins in terms of the surface hydrophilicity/hydrophobicity of polymeric materials. The platelets adhered to the wettability gradient surfaces along the sample length were counted and examined by scanning electron microscopy (SEM). It was observed that the platelet adhesion in the absence of plasma proteins increased gradually as the surface wettability increased along the sample length. The platelets adhered to the hydrophilic positions of the gradient surface also were more activated (possessed more pseudo pods as examined by SEM) than on the more hydrophobic ones. However, platelet adhesion in the presence of plasma proteins decreased gradually with the increasing surface wettability; the platelets adhered to the surface also were more activated on the hydrophobic positions of the gradient surface. This result is closely related to plasma protein adsorption on the surface. Plasma protein adsorption on the wettability gradient surface increased with the increasing surface wettability. More plasma protein adsorption on the hydrophilic positions of the gradient surface caused less platelet adhesion, probably due to platelet adhesion inhibiting proteins, such as high-molecular-weight kininogen, which preferably adsorbs onto the surface by the so-called Vroman effect. It seems that both the presence of plasma proteins and surface wettability play important roles for platelet adhesion and activation.

The effects of ouabain and potassium on peritoneal fluid and solute transport characteristics

BACKGROUND

We reported anomalous transport characteristics of potassium during experimental peritoneal dialysis in rats and suggested that mechanisms of peritoneal potassium transport could be other than simple passive transport. Intracellular transport of potassium in cultured human mesothelial cells was reported to be regulated by three different pathways, such as channels blocked by ouabain, channels blocked by furosemide, and other.

OBJECTIVE

To investigate the effect of ouabain on peritoneal potassium and water transport characteristics.

METHODS

A single 4-hour peritoneal dwell was performed in 28 Sprague-Dawley rats. To minimize the diffusive transport of potassium, 4.5 mmol/L of KCl was added into conventional dialysis solution with 3.86% glucose [acidic peritoneal dialysis solution (APD)]. To evaluate the effect of the pH of dialysis solution on the transport of potassium and water, 4 mmol/L of NaOH was added into the potassium-containing study solutions [neutral peritoneal dialysis solution (NPD)]. To evaluate the effect of a potassium channel blocker on peritoneal potassium transport ATPase sensitive Na+-K+-transport inhibitor, ouabain (10(-5) mmol/L) was added to dialysis solutions immediately before the dwell study in eight rats with APD (APD-O) and six rats with NPD (NPD-O). Ouabain was not added in eight and six rats with APD and NPD (APD-C and NPD-C, respectively). They were used as control. Infusion volume was 30 mL. The intraperitoneal volume (V(D)) was estimated by using a volume marker dilution method with corrections for the elimination of volume marker, radioiodinated human serum albumin (RISA), from the peritoneal cavity (K(E)). The diffusive mass transport coefficient (K(BD)) and sieving coefficient (S) were estimated using the modified Babb-Randerson-Farrell model.

RESULTS

V(D) was significantly higher (p < 0.05 from 90 min to 240 min) and K(E) (0.027+/-0.018 mL/min for APD-O, 0.026+/-0.017 mL/min for NPD-O, and 0.030+/-0.022 mL/min for NPD-C, vs 0.058+/-0.030 mL/min for APD-C, p < 0.05 for each) significantly lower during dialysis with APD-O, NPD-O, and NPD-C than with APD-C. The intraperitoneal glucose expressed as a percentage of the initial amount was significantly higher with APD-O, NPD-C, and NPD-O than with APD-C (p < 0.05 from 90 min to 240 min). K(BD) for sodium was higher during dialysis with ouabain than without ouabain, while K(BD) for urea, glucose, and potassium, and S for urea, glucose, sodium, and potassium did not differ between the four groups.

CONCLUSIONS

The physiologic potassium concentration in neutral dialysis solutions and the use of ouabain decreased the intraperitoneal fluid absorption. The diffusive transport coefficient and sieving coefficient for potassium did not differ, while the diffusive transport coefficient for sodium increased during use of ouabain.

Cell and platelet adhesions on plasma glow discharge-treated poly(lactide-co-glycolide)

Surface treatment, such as plasma glow discharge treatment, onto poly(lactide-co-glycolide) (PLGA) has been investigated to improve the cell-, tissue- and blood-compatibility. Surface-treated samples were characterized by measurement with a contact angle goniometer and electron spectroscopy for chemical analysis (ESCA). The contact angles on the plasma-treated PLGA surfaces decreased with increasing plasma exposure time from 92 degrees to about 30 degrees, i.e., increased hydrophilicity. From the results of ESCA analysis of plasma-treated films, the incorporation of oxygen molecules into plasma onto the PLGA surface was observed. Cell adhesion and growth on plasma-treated PLGA surfaces were more active than on the control. Furthermore, the maximum adhesion and growth of cells in moderate hydrophilicity were investigated. Morphology of the adhered platelets on the plasma-treated PLGA surface showed less activity than on the control, and the number of adhered platelets on the plasma-exposed PLGA sample decreased with decreasing water contact angle. It seems that surface wettability of PLGA plays an important role in cell adhesion, spreading and growth, and platelet adhesion.

Comparative stereochemical analysis of glucose-binding proteins for rational design of glucose-specific agents

There is a need for synthesizing glucose-sensitive molecules which can be used in glucose sensors and self-regulating insulin delivery devices. Currently, glucose-sensitive proteins, such as glucose oxidase and concanavalin A (Con-A), are used for detecting glucose molecules. For long-term in vivo applications, it is necessary to synthesize non-proteineous glucose-sensitive molecules which are biocompatible, nontoxic, cost-effective, and independent of environmental factors such as pH, ionic strength, or the presence of divalent cations. As a first step toward synthesizing glucose sensitive molecules, we have compared glucose-binding sites of four different types of glucose-binding proteins. They are human beta-cell glucokinase, D-xylose isomerase, lectins (Lathyrus ochrus isolectin I and Con-A), and glucose/galactose binding protein. Analysis of the glucose-binding sites of their 3-dimensional crystal structures showed that the hydrogen bonds between the hydroxyl groups of glucose and a few types of amino acid residues of proteins provided the main attraction. In some cases, the same atom was involved in multiple hydrogen bonds. Hydrophobic interactions between the pyranose ring of glucose and aromatic rings of hydrophobic amino acid residues also played an important role in the glucose specificity. A sandwich geometry was observed among the hydrophobic groups. This comparative stereochemical analysis suggests that a possible glucose binding site can be made by placing Asp and Asn around glucose for hydrogen bonding and Phe on both sides of glucose for hydrophobic interaction.

Platelet adhesion onto chargeable functional group gradient surfaces

Functional group gradients were prepared on low-density polyethylene (PE) sheets. The surface density of grafted functional groups was gradually changed along the sample length by way of corona discharge treatment with gradually increasing power following graft copolymerization of acrylic acid (AA), sodium p-styrene sulfonate (NaSS), or N,N-dimethyl aminopropyl acrylamide (DMAPAA). AA and NaSS are negatively chargeable and DMAPAA is positively chargeable in phosphate-buffered saline or plasma solution at pH 7.3-7.4. The prepared functional group gradient surfaces were characterized by measurement of the water contact angle, by electron spectroscopy for chemical analysis, and by Fourier transform infrared spectroscopy in the attenuated total reflectance mode. All these measurements indicated that the functional groups were grafted onto the PE surfaces with gradually increasing density. The platelets adhered to the functional group gradient surfaces along the sample length were counted and observed by scanning electron microscopy. It was observed that the platelet adhesion to the gradient surfaces decreased gradually with the increasing surface density of functional groups. This may be related to the hydrophilicity of the surfaces. The DMAPAA-grafted surface showed a large amount of platelet adhesion, probably due to its positive charge character, while the AA-grafted surface, which is charged negatively, showed poor platelet adhesion. However, the NaSS-grafted surface, which is also charged negatively, showed a relatively large amount of platelet adhesion. This may be associated with the existence of an aromatic ring close to the ionizable group in NaSS. It seems that surface functional groups and their charge character, as well as wettability, play important roles for platelet adhesion.

Pulp reconstruction of fingers with very small sensate medial plantar free flap

The essence in dealing with the pulp deficit accompanying fingertip injuries lies in functional restitution of the inherent skin texture and characteristics unique to that area and sufficient preservation of digital length, along with successful restoration of fine tactile sensation indispensable to delicate and skillful maneuvers. Among various techniques used to meet such demands, the very small sensate medial plantar free flap can be considered an excellent method in view of the skin texture that allows firm grasping, durability to friction rub, a cushion effect, and adequate sensation. Six cases of finger pulp reconstruction with the very small sensate medial plantar free flap are presented. At follow-up examination (an average follow-up of 24.3 months), the patients were evaluated clinically and neurologically. The operative procedures, advantages, and results in clinical cases are presented. Satisfactory results were obtained with sufficient preservation of digital length and good sensory recovery. No functional deficit was found at the donor site.

Identification of urinary dipeptidase as the released form of renal dipeptidase

Amphipathic and hydrophilic forms of human renal dipeptidase and urinary dipeptidase were purified by affinity chromatography using cilastatin, a dipeptidase inhibitor, as the ligand. The sequence analyses of the first ten amino acids of renal and urinary dipeptidases were shown to be identical, and they are Asp-Phe-Phe-Arg-Asp-Glu-Ala-Glu-Arg-Ile. Unambiguous results of amino acid sequencing, the molecular weight of native protein (190 kD), the molecular weight of subunit (47.7 kD) and a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicate that the enzymes are composed of homotetramers. This is the most direct evidence that urinary dipeptidase is the released form of renal dipeptidase. In fact, they are the same enzymes.

EGF inhibits expression of WDNM1 and sulfated glycoprotein-2 genes in mammary epithelial cells

We have previously shown that expressions of ferritin heavy chain (FHC), WDNM1, and sulfated glycoprotein-2 (SGP-2) genes are induced at an involution stage of mammary gland. Here we studied the effect of lactogenic hormones and EGF on the expression of involution-induced genes in HC11 mammary epithelial cells. Insulin, dexamethasone, prolactin, and its combinations did not affect expression of the genes. When cells were cultured in growth medium containing EGF, expression of WDNM1 and SGP-2 genes was strongly inhibited in a dose- and time- dependent manner, whereas expression of FHC gene was not influenced by EGF. Results demonstrate that EGF inhibits expression of WDNM1 and SGP-2 genes in mammary epithelial cells.

Chaperone-like function of lipocortin 1

Lipocortin 1 (LC1) is a 37 kDa member of the annexin family of proteins. It has been proposed to act as a mediator of some of the actions of glucocorticoids in anti-inflammatory and immune suppressive functions. LC1 has been shown to play a role in cell proliferation, apoptosis, and differentiation. However, the exact biological functions of LC1 still remain obscure. Here it is shown that LC1 displays a chaperone-like function. Stoichiometric amounts of LC1 suppressed thermally induced inactivation and aggregation of the test enzymes citrate synthase and glutamate dehydrogenase. LC1 was also effective in refolding guanine hydrochloride-denatured glutamate dehydrogenase, as judged by circular dichroism spectroscopy.

The 5'-upstream region of the rat phospholipase C-beta 3 gene contains two critical Sp1 sites and an HIV Inr-like element

The 5'-upstream region of the rat phospholipase C-beta 3 gene (PLC-beta 3) has been cloned and characterized. Sequence analysis of the 5'-upstream region showed that it contains a GC-rich region (-166 to +1: 79%) and multiple binding sites for the transcription factors Sp1, AP-1 and AP-2, but does not contain a canonical TATA box. Primer extension analysis of total RNA isolated from rat glial cell C6Bul revealed that single transcription start point (tsp) is located at an initiator (Inr) element similar to that found in the HIV promoter. Gel mobility shift and competitive mobility shift assays indicated that this Inr element forms a DNA-protein complex with the HIV Inr-binding protein, LBP-1/CP2 or a homologue. In order to localize functional elements of the 5'-upstream region of the rat PLC-beta 3 gene, 5'-deletion fragments were cloned into a chloramphenicol acetyltransferase (CAT) reporter vector. Transient transfection analyses of the 5'-deletion mutants identified a crucial promoter element located at -128 to -14. Supershift mobility assays, site-directed mutagenesis and DNase I footprints indicated that Sp1 binds to three GC boxes within the sequence between -128 and -14 of the PLC-beta 3 promoter. Transient transfection analyses of promoter constructs containing site-specific mutation(s) of these three GC boxes demonstrated that two GC boxes, located proximal to the tsp, are important elements for normal promoter activity.

Development and characterization of an alginate-impregnated polyester vascular graft

Alignate gels are known to be biocompatible, degradable, and nontoxic. In this study, sodium alginate was impregnated into a porous, knitted polyester graft (Microvel double velour graft) 6 mm in diameter. The alginate-impregnated graft was investigated in vitro and in vivo to evaluate its potential for use as a new vascular graft impervious to blood, while retaining high porosity for tissue ingrowth and biological healing. For in vitro investigation, the coating weight, water permeability, morphology, and mechanical properties of the alginate-impregnated grafts were compared to those of control or commercially available collagen-impregnated (Hemashield) grafts. The water permeability of the controls (1846 mL/min.cm2 at 120 mm Hg) was reduced > 99% by the alginate impregnation, rendering the graft impervious to blood. The coating weight of the alginate was 45 mg/g of graft, producing a much lower value than that of the collagen-impregnated model (310 mg/g). For in vivo investigation, the alginate-impregnated grafts were implanted in the aorta of mongrel dogs without preclotting for scheduled periods ranging from 4 h to 6 months. The control grafts after preclotting and the collagen-impregnated grafts without preclotting were also implanted for 3 and 6 months for comparison. Gross observation of the explanted grafts and histologic examination of the representative sections were conducted for three types of grafts using a light microscope after hematoxylin-eosin staining. No significant differences were observed between the histologic appearance of the alginate-impregnated grafts and that of the preclotted and collagen-impregnated grafts in terms of the degree of inflammation, foreign-body giant cell reaction, and intimal fibrosis. Endothelial-like cells were present on the midsections of all the grafts after 3 months of implantation. The resorption rate of alginate impregnated into the graft was also examined after staining the sections with periodic acid-Schiff reagent, Toluidine blue, and Alcian blue, which are specific for alginates. The staining alginate was partially visible between the graft fabrics up to 1 month after implantation, but was completely resorbed after 3 months. This preliminary study demonstrated that the use of an alginate as a biological sealant instead of proteins such as collagen, gelatin, and albumin may be a feasible approach to developing imprevious textile arterial prostheses, since the proteins have been reported to be generally unstable, hard to obtain in pure forms, not easy to crosslink and control resorption rate, and difficult to render compatible with standard storage and sterilization procedures.

Unilateral multilayered musculocutaneous V-Y advancement flap for the treatment of pressure sore

We have devised a modified technique using the gluteus maximus musculocutaneous flap as multilayered sliding V-Y advancement to cover pressure sores on the sacral area. Nine patients with relatively large (average 7 x 7 cm) sacral grade IV pressure sores underwent unilateral multilayered V-Y advancement flap. All patients were followed for a minimum of 8 weeks. The mean postoperative follow-up was 32.3 months, with a range of 24 to 39 months. Using this technique, the success of surgery, i.e., the percentage of sores that healed, was 100 percent in our patients. The advantages of this technique include sufficient advancement of the flap, coverage of large ulcer defects using only a unilateral musculocutaneous flap, and preservation of the contralateral gluteus maximus muscle for future use.

Single-sample methods to measure GFR with technetium-99m-DTPA

Many single-sample methods have been suggested to simplify the methodology of glomerular filtration rate (GFR) measurement. The relative accuracy of these competing methods is still not clear for clinical practice.

METHODS

Fifty-four GFR studies with 99mTc-DTPA were performed on 37 adult patients (serum creatinine 0.8-10 mg/dl). Each study included a UV/P, plasma clearance method (three-sample) and single-sample methods. The single-sample methods used were those of Christensen and Groth (modified by Watson), Constable, Dakubu, Groth and Aasted, Jacobsson, Morgan, Russell and Tauxe.

RESULTS

When the GFR > or = 30 ml/min (n = 26), all of the single-sample methods were highly correlated with UV/P. The correlation of the single-sample method with the plasma clearance was higher than with UV/P. In this group (GFR > or = 30 ml/min), the Groth 4-hr sample method had the best value of both absolute difference and percent absolute difference (mean +/- s.e. = 11.05 +/- 2.51 ml/min and 14.08% +/- 2.43%, respectively). Most single-sample methods do not perform well at GFR < 30 ml/min (n = 28), and none of them has a good correlation with UV/P or plasma clearance at this level of renal function. However, the Groth and Aasted's 4-hr sample method was the best compared with others (mean +/- s.e. = 8.43 +/- 1.30 ml/min for absolute difference, and 65.91% +/- 16.70% for percent absolute difference).

CONCLUSION

Single-sample methods may not correctly predict GFR in advanced renal failure. Groth and Aasted's method with 4-hr plasma sample has both the lowest mean absolute difference and percent absolute difference in both the group with GFR > or = 30 ml/min and GFR < 30 ml/min. All methods perform acceptably at GFR > or = 30 ml/min.

Interaction of cells on chargeable functional group gradient surfaces

Functional group gradient surfaces where the surface density of grafted functional groups changes gradually along the sample length were prepared on low density polyethylene (PE) sheets by corona discharge treatment with gradually increasing power and graft copalymerization of acrylic acid (AA), sodium p-styrene sulphonate (NaSS), and N,N-dimethyl aminopropyl acrylamide (DMAPAA). AA and NaSS are negatively chargeable and DMAPAA is positively chargeable in phosphate buffered saline or cell culture medium at pH 7.3-7.4. The functional group gradient surfaces were characterized by the measurement of water contact angle, Fourier transform infrared spectroscopy in the attenuated total reflectance mode, and electron spectroscopy for chemical analysis. All these measurements indicated that the functional groups were grafted on the PE surfaces with gradual increase of their density. The interaction of Chinese hamster ovary cells with the functional group gradient surfaces along the sample length was investigated. The cells that had adhered and grown on the surfaces were counted and observed by scanning electron microscopy. It was observed that a greater quantity of the cells had adhered and grown onto the positions with moderate density of the functional groups. This may be related to the hydrophilicity of the surface. The DMAPAA-grafted surface showed a large amount of cell attachment probably owing to the positive charge character, while the AA-grafted surface, which is negatively charged, showed poor cell attachment, as expected. The NaSS-grafted surface which is also negatively charged showed a large amount of cell attachment. This may be closely associated with the existence of an aromatic ring close to the ionizable group in NaSS. It seems that surface functional groups and their charge character as well as wettability play important roles for cell adhesion, spreading, and growth.

Differences in immunophenotyping of mucosal lymphocytes between ulcerative colitis and Crohn's disease

OBJECTIVES

Immunologic studies have characterized the numbers and types of inflammatory cells in diseased inflammatory bowel disease (IBD) mucosa but have yielded conflicting results regarding intestinal lymphocytes activation in IBD. We investigated the levels of lymphocytes subsets, interleukin-2 receptor, transferrin receptor, and T cell receptors in mainly isolated lamina propria lymphocytes. Including intraepithelial lymphocytes of normal colonic mucosa or IBD (ulcerative colitis and Crohn's disease) mucosa to understand the pathogenesis of IBD. We have results from this study.

RESULTS

1) In comparing ulcerative colitis with control, IL-2R (p < 0.05), TR (p < 0.01), and CD3/HLA-DR (< 0.05) showed a significant increase. 2) In comparing Crohn's disease with control, CD3 (P < 0.05), TCR alpha/beta (p < 0.01) and TCR gamma/delta (p < 0.05) showed a significant decrease. 3) In comparing Crohn's disease with ulcerative colitis, CD19 (p < 0.01), TR (p < 0.01), TCR alpha/beta (p < 0.01) and TCR gamma/delta (p < 0.05) showed a significant decrease.

CONCLUSION

From these results, there are increased T cell markers, IL-2R, TR, and CD3/HLA-DR in UC, but differently, decreased CD3, TCR alpha/beta and TCR gamma/delta in CD compared with control. In addition, definitive differences in lymphocytes markers, CD19, TR, TCR alpha/beta and TCR gamma/delta, which are higher in UC than in CD, may elucidate the different immunopathogenesis between UC and CD.

Plasma protein adsorption and platelet adhesion onto comb-like PEO gradient surfaces

Comb-like polyethylene oxide (PEO) surfaces were prepared on low-density polyethylene (PE). The comb-like PEO chain density was changed gradually along the sample lengths by corona discharge treatment with gradually increasing power and the following graft copolymerization of poly(ethylene glycol) monomethacrylate macromers (PEO-MA). The macromers with different PEO repeat unit, 1, 5, and 10, were used. The prepared comb-like PEO gradient surfaces were characterized by water contact angle, Fourier transform infrared spectroscopy in the attenuated total reflectance mode, and electron spectroscopy for chemical analysis. All these measurements indicated that the PEO chains are grafted on the PE surface with gradually increasing density of PEO. Plasma protein adsorption and platelet adhesion on the PEO gradient surfaces decreased with increasing PEO chain length and surface density. As observed by scanning electron microscopy, PEO10-MA-grafted surface with high PEO density was very effective in preventing protein adsorption and platelet adhesion and did not activate the platelets.

Augmentation of tumor metastasis by platelet-activating factor

The effect of platelet-activating factor (PAF) on experimental pulmonary metastasis by the B16F10 murine melanoma and the possible involvement of PAF in the activities of tumor necrosis factor alpha (TNF-alpha) and interleukin 1alpha (IL-1alpha) in tumor metastasis were investigated. i.p. injection of PAF enhanced the lung colonization in a dose- and time-dependent manner. PAF enhanced lung colonization when it was administered after, but not before, B16F10 inoculation. Multiple injections of PAF were more effective than a single injection. Neutralization of endogenous PAF with PAF antagonist BN50739 decreased lung colonization, suggesting that endogenous PAF plays an important role in pulmonary metastases. A single i.p. injection of TNF-alpha or IL-1alpha caused a marked enhancement in lung colonization. TNF-alpha- and IL-1alpha-mediated enhancement in lung colonies was significantly inhibited by BN50739. These results demonstrate that PAF has a metastasis-enhancing effect and is a mediator of the metastatic activities of TNF-alpha and IL-1alpha.

Enhancement of thermostability and catalytic efficiency of AprP, an alkaline protease from Pseudomonas sp., by the introduction of a disulfide bond

A site-directed mutagenesis in AprP, an alkaline protease isolated from Pseudomonas sp. KFCC 10818 was carried out in order to obtain increased thermostability. Sites for cysteine substitutions to form disulfide bond within AprP were chosen by comparing the sequences with aqualysin I, an alkaline thermostable serine protease whose disulfide bonds seems to be important for its thermostability. Gly199 and Phe236 residues were each replaced with cysteine by site-directed mutagenesis. The G199C/F236C mutant enzyme appeared to form a disulfide bond spontaneously during its expression. It also showed improved kinetic parameters for the hydrolysis of a synthetic peptide substrate at pH 8.5 and 10.5 compared to those of the wild-type enzyme. The half-life of the G199C/F236C mutant was found to be 2 to 4.8 times longer than that of wild-type under various experimental conditions, except when tested under reducing condition, where no significant differences in the half-life of the two types were observed. Therefore, it is concluded that the introduction of the disulfide bond enhanced the thermostability and the catalytic efficiency of the enzyme AprP.

Blood and cell compatibility of gelatin-carrageenan mixtures cross-linked by glutaraldehyde

Mixtures of gelatin and iota-carrageenan cross-linked by glutaraldehyde were prepared and their physical properties and blood and cell compatibility were compared to gelatin as a control material. According to scanning electron microscopic observation of fracture surfaces, the mixtures were composed of dispersed and continuous domains which might be generated by phase separation of carrageenan. The thermal degradation temperature of iota-carrageenan in the mixtures rose with increasing gelatin content. The swelling process in the mixtures proceeded slower than in gelatin. Tensile strengths of the mixtures, except that containing 50% iota-carrageenan, increased with increased amounts of iota-carrageenan in the mixtures. The iota-carrageenan contents at the surfaces of the mixtures were generally higher than those admixed originally. Static friction coefficients of the mixtures were lower than that of gelatin. Plasma recalcification times of the mixtures were longer than that of gelatin. Platelet adhesion of the mixtures was lower than that of gelatin, while cell adhesion and growth assays using Chinese hamster ovary cells showed that cell adhesion and growth were not dependent on adding iota-carrageenan. It was concluded that blood compatibility of the mixtures increased and cell compatibility did not decrease, compared to gelatin.

In situ detection of hepatitis C virus RNA in liver tissue using a digoxigenin-labeled probe created during a polymerase chain reaction

The cellular localization of hepatitis C virus (HCV) RNA in liver tissue was studied by nonisotopic in situ hybridization using a digoxigenin-labeled cDNA probe created during a polymerase chain reaction on samples from 16 patients with chronic HCV infection. Hybridization signals were recognized in the cytoplasm of the hepatocytes, and a few hepatocytes had hybridization signals in the nucleus as well. HCV RNA positive hepatocytes were found in 1 of 9 patients with chronic persistent hepatitis, 2 of 5 patients with chronic active hepatitis, and in each of 2 patients with chronic active hepatitis and cirrhosis. Positive signals were found in many hepatocytes within the lobule in liver sections of patients with advanced chronic active hepatitis. A number of HCV RNA positive hepatocytes were found in nodules, but not in the area of fibrosis. On the other hand, positive signals were found in a few hepatocytes scattered in the lobule in a patient with chronic persistent hepatitis. The mean ALT levels in the patients with positive signal (175.6 +/- 44.2 U/L) were significantly higher than in those without a signal (70.27 +/- 16.1 U/L) (P < 0.05). The findings suggest that a larger amount of HCV may be present during the advanced than during the early stages of type C hepatitis and nonisotopic in situ hybridization using a digoxigenin-labeled HCV cDNA probe created during a polymerase chain reaction deserves wider application for the detection of HCV replication in specimens.

The effect of dialysate acidity on peritoneal solute transport in the rat

OBJECTIVE

To investigate the possible effect of unphysiologically low pH in dialysis fluid on peritoneal transport.

DESIGN

A 4-hour single-cycle experimental session of peritoneal dialysis was performed in six Sprague-Dawley rats using Dianeal 3.86% solution modified by adding 5 mmol/L of sodium hydroxide, neutral pH solution (NpHS) (pH 7.4). The intraperitoneal volume (VD) and peritoneal bulk fluid reabsorption (Qa) were calculated using a marker, 131I-labeled human serum albumin (RISA). The diffusive mass transport coefficient (KBD) as well as sieving coefficient (S) for glucose, urea, sodium, and potassium were calculated using the Babb-Randerson-Farrell model. The same study was performed in seven rats using Dianeal 3.86% solution, acidic pH solution (ApHS) (pH 5.7) to provide control values.

RESULTS

The dialysate pH was stable with NpHS; 45 min after the infusion of ApHS it increased rapidly and reached the physiological value 7.4. Dialysate volume and KBD values for sodium and potassium with NpHS were significantly higher than with ApHS, while the KBD values for glucose and urea did not differ between the two solutions. S values for sodium and urea did not differ between the two solutions, while the values for glucose and potassium with NpHS were significantly higher and lower, respectively, than the values with ApHS (0.92 +/- 1.04 vs 0.04 +/- 0.63 and 0.56 +/- 060 vs 1.15 +/- 0.39, p < 0.05). The absorption of glucose from the dialysis solution expressed as a percentage of the initial amount of dialysate glucose was significantly lower with NpHS than with ApHS at 30 min (17.3 +/- 1.7% vs 29.7 +/- 2.0%, p < 0.05).

CONCLUSION

We conclude that the peritoneal transport of fluid and small solutes might to some extent be influenced by the acidity of the dialysis solution. The vasodilatory effect of acidic dialysis solution might be the most important mechanism for these differences. However, a larger KBD value and a lower S value for potassium and higher S values for glucose during dialysis with the neutral dialysis solution may indicate that transport mechanisms other than simple passive transport are involved in peritoneal transport for glucose and electrolytes.

Different effects of base analog substitutions in BamHI restriction site on recognition by BamHI endonuclease and BamHI methylase

BamHI endonuclease and BamHI methylase were used to investigate their specific interaction with the common recognition sequence, GGATCC. Five derivatives of the oligonucleotide, GACGGATCCGTC, containing a variety of single-base analog substitutions within the hexameric recognition core were synthesized. Steady-state kinetics for the reaction of the endonuclease and the methylase showed that both enzymes recognize the sequences by contacting with functional groups exposed in both major and minor grooves of the site but in different ways. Removal or substitution of the 5-methyl group in thymidine blocked the endonuclease reaction completely but still allowed the methylase reaction with less efficiency. The data also showed that the methylase made a critical minor groove contact with the 2-amino group of the first G but the endonuclease did with that of the second G.

Cell behaviour on polymer surfaces with different functional groups

Surfaces with differently chargeable functional groups were prepared on low density polyethylene sheets by corona discharge treatment, followed by graft copolymerization of acrylic acid (-COOH, negatively chargeable) and a subsequent substitution reaction of carboxylic acid groups to hydroxyl (-CH2OH, neutral) or amide (-CONH2, neutral) groups. The amide groups grafted on the surface were further converted to amine groups (-CH2NH2, positively chargeable). The prepared surfaces were characterized by measuring the water contact angle, electron spectroscopy for chemical analysis and Fourier-transform infrared spectroscopy in the attenuated total reflectance mode. It was observed that the wettability of the different functional group-grafted surfaces largely increases compared with the control surface but is not much affected by the kind of functional groups grafted. The interaction of Chinese hamster ovary cells with the functional group-grafted surfaces was investigated. The cells adhered and grown on the surfaces were counted using an electronic cell counter and observed by a scanning electron microscope. The surface grafted with amine groups was best for cell adhesion, spreading and growth probably owing to the positively chargeable character in aqueous cell culture medium. For surfaces grafted with neutral functional groups, the surface grafted with hydroxyl groups showed better cell spreading than that grafted with amide groups.