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.

Reconstitution of the skeletal muscle ryanodine receptor-Ca2+ release channel protein complex into proteoliposomes

The 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid-solubilized 30 S ryanodine receptor (RyR)/Ca2+ release channel complex from rabbit skeletal muscles, purified by density gradient centrifugation, was reconstituted with an excess of phospholipid into proteoliposomes by removal of the detergent by dialysis. Reconstituted proteoliposomes were concentrated by centrifugation, frozen and thawed, and sonicated. [3H]Ryanodine binding measurements indicated close to 50% recovery of calculated binding activity following reconstitution of the purified RyR and dynamic light scattering measurements a mean vesicle diameter of approximately 150 nm. Using these values, a functional RyR was estimated to be present in only a small fraction (< 15%) of the reconstituted vesicles. SDS-polyacrylamide gel electrophoresis of trypsin-treated proteoliposomes revealed that about four-fifths of the reconstituted 30 S complex was readily accessible to proteolytic attack. Vesicle-45Ca2+ flux and fusion of proteoliposomes with planar lipid bilayers showed that the reconstituted channel complex could be activated by Ca2+ and ATP, inhibited by Mg2+ and ruthenium red, and modified by ryanodine, similarly as observed for native sarcoplasmic reticulum vesicles. These results suggest that the method described here results in the reconstitution of a functional channel and thus provides the opportunity to study the structure and function of the sarcoplasmic reticulum Ca2+ release channel under well defined conditions.

The effect of radiation therapy on immune function in patients with squamous cell lung carcinoma

The immune response is impaired in patients with malignancy, and radiation therapy (RT) can exacerbate the cancer induced-attenuation of immune response. In order to search for the fine mechanisms behind the RT-induced attenuation of cell-mediated immune response, we measured the number of lymphocytes in peripheral blood, its subsets, and lymphoblast transformation induced by phytohemagglutinin (PHA), purified protein derivatives (PPD), mitogenic monoclonal antibody anti-CD3, and mitogenic combination of anti-CD2 antibodies 9-1 and 9.6 before and after RT in 19 patients with squamous cell lung cancer. Radiation therapy significantly decreased the total numbers of lymphocytes, CD-3, CD-4, and CD8-positive lymphocytes in peripheral blood. However, RT did not change the percentages of lymphocytes and its subsets. Radiation therapy increased the percentage of interleukin 2 (IL-2) receptor-positive lymphocytes, and RT significantly decreased in vitro lymphoblast transformation by PHA, PPD, or monoclonal antibodies to T-cell surface antigens (anti-CD2 or anti-CD3). In vitro incubation with IL-2 did not increase lymphoblast transformation by anti-CD3 before RT but significantly increased after RT. In conclusion, we suggest that one of the fine mechanisms behind the RT-induced suppression of immune responsiveness of patients with lung cancer is a defect in IL-2 synthesis by lymphocytes.

Cloning of Pseudomonas fluorescens carboxylesterase gene and characterization of its product expressed in Escherichia coli

A gene (estC) coding for an esterase (esterase III) of Pseudomonas fluorescens was cloned into Escherichia coli JM83. DNA sequencing showed a single open reading frame with GTG as a translation initiation codon for esterase III. This was confirmed by N-terminal amino acid sequence analysis of the purified esterase III protein from an E. coli clone. The promoter sequence and a potential Shine-Dalgarno sequence were followed by the coding sequence of the estC gene. The amino acid sequence deduced from the nucleotide sequence contains the consensus active site sequence, G-X-S-X-G, of serine esterase. The esterase III expressed in an E. coli clone was purified by ion-exchange chromatography and gel filtration. The native form of the enzyme was a monomer with a molecular weight of 41,000. The results of substrate specificity and the inhibitor studies suggest that this enzyme is a carboxylesterase (EC 3.1.1.1) and a serine residue is present at the active site of the enzyme.

Quantitative modeling of responses of anuran retina: stimulus shape and size dependency

Teeters and Arbib presented a model of the anuran retina which qualitatively accounts for the characteristic response properties used to distinguish ganglion cell type in anurans. In this paper we test the model's ability to reproduce quantitatively tabulated data on the dependency on stimulus shape and size, with a new implementation of the model in the neural simulation language NSL. Data of Ewert and Hock relating toad R2, R3, and R4 ganglion cell responses to moving worm, antiworm, and square-shaped stimuli of various edge lengths are used to test stimulus shape and size dependency. A close match to the data can be achieved by tuning some of the model parameters while still retaining the characteristic responses to the typical stimulus types. We stress here the importance of a populational approach to the models. We place more emphasis on the variation of response properties in a population of neurons of the same class, rather than questing for the neuron of a given type. As an example of the populational approach we offer a model for the respiratory R3 response following researchers who argue that a subclass of R3 neurons are activated by stationary boundaries owing to the anuran's self induced respiratory eye movement.

Immobilization of proteins on poly(methyl methacrylate) films

Polymethyl methacrylate (PMMA) films were treated by oxygen plasma discharge followed by acrylic acid (AA) grafting. The amount of carboxyl groups introduced by the grafting of AA on to the film surfaces was in the range 0.47-9.48 mumol/cm2, depending on the pressure of the plasma chamber during the discharge treatment. The carboxyl groups of the PMMA film surface previously activated with water soluble carbodiimide were coupled with bovine serum albumin, collagen and gelatin. The protein immobilization on the surface was confirmed by attenuated total reflection Fourier transform infra-red spectroscopy (ATR-FTIR) and electron spectroscopy for chemical analysis (ESCA). The amount of albumin, collagen and gelatin immobilized on the PMMA surface was 6.25, 7.25 and 13.75 micrograms/cm2, respectively, as determined by the coomassie brilliant blue-protein interaction. The water contact angle of the PMMA film was markedly decreased by oxygen plasma treatment, AA grafting or protein immobilization, indicating the increase of hydrophilicity of the surface-modified PMMA films. The protein-immobilized PMMA films may be widely used as a biocompatible material.

Soluble interleukin-2 receptor and cellular profiles in bronchoalveolar lavage fluid from patients with bronchial asthma

BACKGROUND

To elucidate the role of T-cell activation in the physiologic changes and cellular infiltrations in the bronchial tree of patients with symptomatic bronchial asthma, we measured the concentration of soluble interleukin-2 receptor (sIL-2R), cellular compositions and IL-2R expression on cells in bronchoalveolar lavage (BAL) fluid. We also measured physiologic parameters, including a provocation concentration of histamine required to reduce the forced expiratory volume in 1 second by 20% of the prechallenge baseline (PC20).

RESULTS

The concentration of sIL-2R and the ratio of IL-2R expression on CD3 positive lymphocytes were significantly higher in BAL fluid from 20 patients with symptomatic bronchial asthma than concentrations in fluid from nine healthy controls (p < 0.01) and six asymptomatic patients with bronchial asthma (p < 0.05). The concentration of sIL-2R correlated with the percentage of IL-2R expression on CD3 positive lymphocytes (rs = 0.709, p < 0.01). There was no difference in sIL-2R concentration of BAL fluid between the healthy control and the patient with asymptomatic bronchial asthma. Among the inflammatory cells recovered in BAL fluid, the percentages of eosinophils showed significant positive correlation with the concentration of sIL-2R in BAL fluid in the patients with bronchial asthma. The concentration of sIL-2R significantly correlated with forced expiratory volume one second, peak expiratory flow rate, and PC20 when observed in all study subjects, but not in the patients with bronchial asthma.

CONCLUSION

We conclude that T-cell activation within the bronchial tree appears to have a role in the infiltration of eosinophils into the bronchial tree, which may lead to enhanced bronchial hyperreactivity in patients with bronchial asthma.

A wettability gradient as a tool to study protein adsorption and cell adhesion on polymer surfaces

A new method for preparing a wettability gradient on polymer surfaces was developed. Low density polyethylene sheets were treated in air with corona from a knife-type electrode whose power gradually increases along the same length. The polymer surfaces oxidized gradually with the increasing 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 interactions of model protein and cells in terms of the surface hydrophilicity/hydrophobicity of polymeric materials.

Expression of a cardiac Ca(2+)-release channel isoform in mammalian brain

Mammalian brain possesses ryanodine-sensitive Ca2+ channels, which in muscle cells mediate rapid Ca2+ release from intracellular stores during excitation-contraction coupling. Analysis of bovine brain ryanodine receptor (RyR) channels suggests specific expression of the cardiac-muscle RyR isoform in mammalian brain. Localization using cardiac-muscle RyR-specific antibodies and antisense RNA revealed that brain RyRs were present in dendrites, cell bodies and terminals of rat forebrain, and highly enriched in the hippocampus. Activity of skeletal-muscle RyR channels is coupled to sarcolemmal voltage sensors, in contrast with cardiac-muscle RyR channels, which are known to be Ca(2+)-induced Ca(2+)-release channels. Thus Ca(2+)-induced Ca2+ release from intracellular stores mediated by brain RyR channels may be a major Ca(2+)-signalling pathway in specific regions of mammalian brain, and hence may play a fundamental role in neuronal Ca2+ homoeostasis.

Renal functional response to captopril during diuretic therapy

Antihypertensive agents may modify the renal effects of angiotensin converting enzyme inhibition (ACEI). This potential interaction, which is important in the diagnosis of renovascular hypertension was studied in two rat models with and without diuretic treatment prior to ACEI. Acute intravenous administration of furosemide or hydrochlorothiazide in one-kidney, one-clamp animals (1K1C) did not change glomerular filtration rate (GFR) or effective renal plasma flow (ERPF). ACEI administration after furosemide and hydrochlorothiazide decreased GFR (p less than 0.001, p less than 0.01) but not ERPF. Chlorothiazide administered to 1K1C prior to ACEI, decreased GFR (p less than 0.02) but not ERPF captopril administration to 1K1C which received hydrochlorothiazide intraperitoneally for 7-10 days decreased GFR (p less than 0.007) and ERPF (p less than 0.02), while two-kidney, one-clamp animals (2K1C) decreased GFR only in the clamped kidney (p less than 0.005). ERPF in 2K1C increased only in the contralateral kidney (p less than 0.01). Without diuretic 1K1C animals decreased GFR and ERPF after ACEI (p less than 0.005, P less than 0.001). In the clamped kidney of 2K1C rats, GFR and ERPF decreased significantly (p less than 0.0005, p less than 0.004) and contralateral kidney ERPF increased (p less than 0.001), but GFR did not. The consequences of ACEI on GFR are similar with or without diuretic. These data suggest that diuretic therapy may not significantly interfere with ACEI evaluation of renovascular hypertension.

Serum alpha 1-antitrypsin in patients with hepatocellular carcinoma

To evaluate the diagnostic value of alpha 1-antitrypsin (alpha-AT) as a tumor marker for hepatocellular carcinoma (HCC), we studied the serum levels of alpha-AT by rocket immunoelectrophoresis and alpha-fetoprotein (alpha-FP) by radioimmunoassay in 46 proven HCC patients, 43 cirrhosis patients and 200 healthy blood donors. The mean alpha-AT level of the 46 patients with HCC (4.8 +/- 2.7 mg/ml) was significantly higher than that of 200 healthy control subjects (1.7 +/- 0.7 mg/ml) (P less than 0.0001). The sensitivity of alpha-AT in 24 patients with high level of alpha-FP (greater than 400 ng/ml) and 22 patients with low level of alpha-FP (less than 400 ng/ml) were 96% and 64%, respectively. There was no substantial correlation between alpha-FP and alpha-AT in the two groups (alpha-FP greater than 400 ng/ml, alpha-FP less than 400 ng/ml) (r = 0.078, 0.064). The sensitivity for HCC using alpha-FP level alone (greater than 400 ng/ml) was only 52%, and the sensitivity using alpha-AT level alone (greater than 3.2 mg/ml) was 76% of the 46 patients. Combining both tests, sensitivity was improved only to 80%.

Renin predicts diastolic blood pressure response to nonpharmacologic and pharmacologic therapy

OBJECTIVE

Plasma renin activity was measured at baseline and 6 months in a trial of nonpharmacologic therapy of mild hypertension to determine whether plasma renin activity predicts the diastolic blood pressure (DBP) response to nonpharmacologic therapy.

DESIGN, SETTING, AND PARTICIPANTS

Randomized controlled trial of volunteers from the general community with mild hypertension (DBP between 90 and 100 mm Hg), off all antihypertensive therapy at baseline, treated in special research clinics (n = 593).

INTERVENTIONS

Subjects were randomly assigned to usual, weight loss, or low sodium/high potassium diet and then randomly assigned to receive placebo, chlorthalidone, or atenolol.

MAIN OUTCOME MEASURES

Renin was analyzed as plasma renin activity and as a renin index (logarithm of 24-hour urinary sodium excretion times logarithm of plasma renin activity) (593 patients at baseline and 6 months) to correct for varied sodium intakes. The DBP was measured using the random zero device.

RESULTS

Change in DBP at 6 months could be predicted from baseline plasma renin activity or renin index. The DBP was decreased after 6 months of therapy by 2 mm Hg for each unit increase in baseline plasma renin activity and by 0.16 mm Hg for each unit increase in baseline renin index. Patients in the highest renin index quartile had a greater DBP response to atenolol therapy, and patients in the lowest renin index quartile had a greater DBP response to chlorthalidone therapy. Weight loss diet achieved a greater reduction in DBP in patients with higher baseline renin index and had an additive effect on DBP response in both of the drug groups. Patients on a weight loss diet receiving placebo in the highest baseline renin index quartile had a reduction in DBP of 12.4 mm Hg, compared with 4.4 mm Hg in the lowest baseline renin index quartile (P = .009). A low sodium/high potassium diet had a lesser effect than a weight loss diet on pharmacologic therapy. As with the weight loss diet, patients on a low sodium/high potassium diet in the highest baseline renin index quartile had a greater reduction in DBP than patients in the lowest baseline renin index quartile.

CONCLUSIONS

These data suggest a significant relationship between baseline levels of plasma renin index and the likelihood of success of nonpharmacologic treatment of hypertension.

The effect of captopril on glucoheptonate uptake in experimental renal artery stenosis

This study attempted to evaluate the role of glucoheptonate (GHA) in captopril renography in an in vivo laboratory investigation in which postcaptopril glucoheptonate uptake was analysed in awake 2KlC hypertensive rats. Clamped kidney uptake in a previous study was greater in the poststenotic kidney than in the normal kidney (P = 0.01) in rats with mild renal artery stenosis. A glucoheptonate renogram protocol was developed for use in rats anaesthetized with sodium pentobarbital. An 123I-hippuran scan was performed to determine the relative renal function, followed by a control 99Tcm-GHA scan. Five minutes after administering captopril, another 99Tcm-GHA scan was performed. Relative renal uptake was determined between 30 and 90 s postinjection. 99Tcm-GHA uptake in the clamped kidney was more than 50% of total uptake in 3/9 of the abnormal rats' control scans. No abnormal rats clamped kidney 99Tcm-GHA uptake was greater than 50% in the postcaptopril scans. Captopril reduced GHA uptake in all nine of the animals with baseline scans. These findings suggest that the laboratory observation of captopril induced paradoxically increased 99Tcm-GHA uptake in renal artery stenosis may not be observed scintirenographically. Moreover, the data support a potential value of glucoheptonate in captopril renography.

Effects of erythropoietin-induced hemopoiesis on peritoneal transport and on in vitro T cell response in CAPD

In order to investigate the therapeutic efficacy of subcutaneously administered erythropoietin (rHuEPO) and the effects of rHuEPO-induced hemopoiesis on peritoneal transport and on cellular immune responses, we performed standardized peritoneal equilibration tests and measured T cell subsets and phytohemagglutinin (PHA)-induced interleukin-2 receptor (IL-2R) expression of PBMC by flow cytometry before and after subcutaneous rHuEPO (Eprex-, Cilag), 4000 U twice weekly, in 13 stable CAPD patients. Hct increased from 21.3 +/- 3.4% to 30.0 +/- 4.8% after 1 mo and to 32.7 +/- 4.9% after 2 mon of rHuEPO. Drained volume after 4 hrs of dwell with 4.25% dialysate increased from 2,675 +/- 204 ml to 2,807 +/- 174 ml (P < 0.05). D4/P4 creatinine increased from 0.68 +/- 0.07 to 0.71 +/- 0.06 (P < 0.05) and creatinine clearance from 7.57 +/- 0.71 to 8.03 +/- 0.63 ml/min (P < 0.05). The number of total circulating lymphocytes, T4,T8, T4/T8 with or without PHA did not change after rHuEPO. PHA-induced IL-2R expression by PBMC as expressed by mean channel of fluorescence intensity increased from 149.8 +/- 6.7 to 156.8 +/- 6.1 (P < 0.05).

CONCLUSION

Subcutaneous rHuEPO is effective in correcting anemia in CAPD patients. rHuEPO-induced hemopoiesis is associated with increase in peritoneal creatinine and water transport and also with PHA-induced IL-2R expression.

Subcutaneously implanted catheters reduce the incidence of peritonitis during CAPD by eliminating infection by periluminal route

Recent experiences with Y-connectors suggest that the flush-before-fill effectively reduces intraluminal infection. Periluminal infection, however, remains an important route of peritonitis (P). We have recently reported reduced P incidence with the introduction of a new access technique as described by Moncrief in which the external segment of peritoneal catheter is left implanted subcutaneously for 6 weeks before exteriorization and bag exchanges. P developed once every 14.0 patient-mos with the new access while the incidence was one episode per 10.7 mos with conventional access. Significantly fewer patients with the new access compared to those with conventional access experienced P during the observation period (p < 0.01). Although the overall incidence of exit-site infection (ESI) was not different, there were significantly fewer episodes of simultaneous P and ESI with the new access (2P in 47 episodes of ESI) than with conventional access (36P in 126 ESI). While 10 of the 36 episodes of simultaneous infection in the conventional technique were caused by same organisms, none of the 2 episodes with the new access technique was caused by same organisms.

CONCLUSION

The results of this study suggest that the new access technique reduces P incidence by virtually eliminating infection by the periluminal route.

Cell adhesion and growth on polymer surfaces with hydroxyl groups prepared by water vapour plasma treatment

Various polymer surfaces--polyethylene, polypropylene, polystyrene, polyethylene terephthalate and poly(methyl methacrylate)--were modified by water vapour plasma discharge treatment. The plasma-treated polymer surfaces were characterized by water contact angle measurement and electron spectroscopy for chemical analysis. It was observed that by the water vapour plasma treatment, the wettability of the polymer surfaces increases largely and almost all functional groups produced on the surfaces are hydroxyl groups. The interactions of Chinese hamster ovary cells with the polymer surfaces having hydroxyl groups by plasma treatment were investigated. The cells adhered and grown on the polymer surfaces were counted using a haemocytometer and photographed with an inverted microscope with a camera attached. The water vapour plasma-treated polymers showed good adhesion, spreading and growth properties on the surfaces with high hydroxyl group density. We confirmed that the water vapour plasma treatment is a simple and effective method to produce hydroxyl groups on the polymer surfaces, which probably have a positive effect on cell adherence.

Determination of resin and fatty acids in sediments near pulp mill locations

A gas chromatographic method for the determination of resin and fatty acids in sediments is described. In this procedure, the sediment sample was air-dried and soxhlet-extracted with a mixture of acetone--methanol (88:12, v/v) in the presence of hydrochloric acid. The acids extracted were converted into their pentafluorobenzyl esters and were then cleaned up on a deactivated silica gel column. Final analysis was performed on either a DB-17 or a DB-5 capillary column with electron-capture detection. Quantitative recovery was obtained from fortified sediments for all acids except palustric, neoabietic and levopimaric acids. The detection limit of all acids in this method was 0.1 micrograms/g based on 1 g of sample. This procedure has been successfully applied to the monitoring of resin and fatty acids in sediment samples collected in the vicinity of several Canadian pulp mill locations.

Behavioral teratogenicity of methamphetamine

Pregnant Wistar rats were given daily subcutaneous administrations of methamphetamine (MAPT; varying doses ranging from 1.0 to 4.5 mg/kg) from days 7 to 20 of gestation and teratogenic effects have been determined. The teratogenic effects inducible with orally administered caffeine (90 mg/kg/day) for the same durations were used as the positive controls. MAPT doses greater than 2.0 mg/kg have suppressed the rate of maternal weight gain. Some of the offsprings (F1) of the prenatal MAPT treated groups had decreased growth rate and delayed development of physical characters and functional reflexes. The male offsprings of the MAPT treated groups had significant decreases in their spontaneous motor activity but had enhanced conditioned avoidance responses. However, the mating performances of these offsprings were not affected. These results indicated that prenatal exposure of MAPT may induce some behavioral teratogenicity in rats.

Ragweed IgE and IgG4 antibody in nasal secretions during immunotherapy

We have developed sensitive amplified immunoassays for measurement of IgE and IgG4 ragweed (RW) antibodies in unconcentrated nasal washes. IgE to Amb a I (formerly antigen E) can be assayed to less than 0.1 ng/ml using IgE capture by anti-IgE on microtitre plates and an alkaline phosphatase-conjugated Amb a I with an amplification substrate technique. IgG4 to whole RW extract was assayed to less than 0.01 ng/ml by amplification ELISA using monoclonal anti-IgG4. Nasal washes (NW) (10 ml) and serum were obtained in December from 22 RW-sensitive patients before and after 1 and 2 yr of RW immunotherapy (IT), and assayed for Amb a I IgE or RW IgE and RW IgG4 antibodies Amb a I IgE could be measured in the NW of 15/22 pre IT, 19/22 at 1 yr IT, but only 3/10 at 2 yr IT (compared with pre-IT, P less than 0.05). Mean Amb a I IgE in NW was 0.66, 0.36 and 0.21 ng/ml at pre, 1 yr and 2 yr IT (P-values greater than 0.05). Mean serum RW IgE, was 76, 55 and 27 ng/ml at pre, 1 yr and 2 yr IT (P-values greater than 0.05). Amb a I IgE in nasal washes was correlated with RW IgE in serum (r = 0.56, P less than 0.001, n = 44). RW IgG4 was detectable in NW of 15/22 pre-IT, 18/22 at 1 yr IT and 9/10 at 2 yr IT (P-values greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of serum urokinase on urine fibrinolytic activity

The purpose of this study was to see if the serum level of urokinase might influence the urine fibrinolytic activity. Serum fibrinolytic activity precipitated in dextran sulfate euglobulin fraction was measured on the plasminogen-rich plate before, during, and after the urokinase infusion. The fibrinolytic activity of euglobulin increased during urokinase infusion by dose-dependent pattern (n = 4, mean: 230%, range: 173-333% of basal level) and decreased below the basal level after cessation of urokinase (n = 4, mean: 18%, range: 0-27% of basal level). There was inverse correlation between the urine fibrinolytic activity and serum fibrinolytic activity in all cases (r = -0.75, 0.01 less than p less than 0.02 in case 2; r = -0.88, 0.0001 less than p less than 0.005 in case 3; r = -0.74, 0.05 less than p less than 0.10 in case 1a and r = 0.59, 0.05 less than p less than 0.10 in case 1b). This finding suggests that the urine fibrinolytic activity production was under control of the serum urokinase level with feedback mechanism.

Atrophy of left lobe of the liver associated with hepatolithiasis and cholangiocarcinoma

A case of liver atrophy associated with hepatolithiasis and cholangiocarcinoma is presented. Intraductal calculus and left hepatic lobar atrophy were seen on both ultrasound and computerised tomography examinations. The lobar atrophy was accompanied by hypoplasia of left common hepatic artery. Cholangiocarcinoma was diagnosed on histology. There have been several reported cases of hepatolithiasis and cholangiocarcinoma. To our knowledge, there has been only one reported case of hepatolithiasis and cholangiocarcinoma with liver atrophy (Nishihara K et al 1986) but this was not angiographically demonstrated.