Simulated Cuspal Deflection and Flexural Properties of Bulk-Fill and Conventional Flowable Resin Composites

CLINICAL RELEVANCE

Some bulk-fill flowable resin composites produce less cuspal deflection than a conventional incrementally filled flowable resin composites.

SUMMARY

Objective: This study investigated simulated cuspal deflection and flexural properties of bulk-fill and conventional flowable resin composites.Methods and Materials: Five bulk-fill and six conventional flowable resin composites were evaluated. Aluminium blocks with a mesio-occlusal-distal cavity were prepared and randomly divided into groups for each of the different measurement techniques and were further subdivided according to the type of flowable resin composite. The simulated cuspal deflection caused by the polymerization of resin composite within an aluminium block was measured using a highly accurate submicron digimatic micrometer or a confocal laser scanning microscope (CLSM). In addition, the flexural properties of tested resin composites were measured to investigate the relation between cuspal deflection and flexural properties, and the resin composites were observed using scanning electron microscopy.Results: Simulated cuspal deflection of some bulk-fill flowable resin composites was found to be significantly lower than or similar to those for conventional counterparts, regardless of the measurement method. There were statistically significant differences in flexural properties depending on the material, regardless of the type of flowable resin composite. Pearson correlation analysis did not reveal a statistically significant relationship between flexural properties and cuspal deflection.Conclusion: These results indicate that some bulk-fill flowable resin composites exhibit lower cuspal deflection with the bulk-filling technique than is shown by conventional flowable resin composites using the incremental filling technique. Simulated cuspal deflection can be measured using either a micrometer or CLSM, but this experiment failed to show a significant relationship between cuspal deflection and flexural properties of flowable resin composites.

Etch-and-rinse vs self-etch mode for dentin bonding effectiveness of universal adhesives

In this study, dentin bond fatigue resistance and interfacial science characteristics of universal adhesives through etch-and-rinse and self-etch modes were investigated. Resin composite was bonded to human dentin with four universal adhesives, namely, Adhese Universal, All-Bond Universal, G-Premio Bond, and Scotchbond Universal Adhesive. The initial bond strengths, bond fatigue strengths, and interfacial science characteristics of the universal adhesives with dentin through etch-and-rinse and self-etch modes were determined. Bond fatigue resistance (initial bond strength and bond fatigue strength) of universal adhesives in etch-and-rinse mode showed no significant difference in contrast to that in self-etch mode and was material-dependent regardless of the etching mode. Although phosphoric acid conditioning of dentin did not have a strong impact on the bond fatigue resistance, surface free energy and parameters of dentin were significantly decreased by etching and by application of universal adhesives regardless of etching mode. Changes in γ_S and γ_S^h for when universal adhesive was applied to etched and ground dentin were significantly different depending on the adhesive. The results suggest that bonding performance of universal adhesives was effective in both etching modes; however, bonding mechanisms may be different for each.

Effect of Reduced Universal Adhesive Application Time on Enamel Bond Fatigue and Surface Morphology

Objective:

The purpose of this study was to evaluate the effect of reduced application times of universal adhesives on enamel bond fatigue and surface morphology of the treated enamel with constant force atomic force microscopy (AFM).

Methods:

Four universal adhesives—Adhese Universal (AU), Clearfil Universal Bond Quick (CU), G-Premio Bond (GP), and Scotchbond Universal Adhesive (SU)—were evaluated in a laboratory for their ability to adhesively bond resin composite to enamel. Shear bond strengths were initially determined using 15 specimens per test group for each adhesive. Shear fatigue strengths were then determined using 20 specimens per test group for each the adhesives. The fatigue specimens were loaded using a sine wave at a frequency of 20 Hz for 50,000 cycles or until failure occurred. AFM observations, surface Ra roughness measurements, and geometric surface area evaluations of enamel surface treated with the adhesive agents were also conducted.

Results:

A strong relationship was found between the initial shear bond strength and shear fatigue strength for enamel surface Ra roughness but not for geometric surface area. The initial shear bond strength and shear fatigue strength of CU and GP were not influenced by different application times, unlike those of AU and SU. While the surface area of enamel treated with the adhesive agents was not significantly influenced by different application times and type of adhesive, surface Ra roughness of the enamel in the AU and SU groups significantly increased with increasing application time, unlike CU and GP.

Conclusions:

The results of this study suggest that universal adhesives, used with reduced application times, have adequate Ra surface roughness to provide sufficient resistance to enamel bond fatigue at application times from <1 second to 20 seconds, while the geometric surface area of adhesive-treated enamel did not show any significant changes at these different application times.

Effect of a coating material containing surface reaction-type pre-reacted glass-ionomer filler on prevention of primary enamel demineralization detected by optical coherence tomography

We used optical coherence tomography to examine the effect of a coating material containing surface reaction-type pre-reacted glass-ionomer (S-PRG) filler on primary enamel demineralization in 18 extracted human primary teeth. The pulp was removed, and each tooth was ultrasonically cleaned with distilled water. Six teeth were treated with 0.1-M lactic acid buffer solution (De group). In the second group (n = 6), a thin film of coating material was applied before demineralization (PRG group). A third group (Control group; n = 6) was maintained in artificial saliva. Using optical coherence tomography, we measured peak signal intensity (dB) and width at 1/e² (µm) at predetermined locations on the enamel surface and calculated integrated values. All data were analyzed with ANOVA and the Tukey-Kramer test (α = 0.05). Although changes in integrated values differed between groups, there was a small but significant increase in the Control group and a small but significant decrease in the De group. In the PRG group, integrated values were significantly higher at 7 days after the start of the experiment and significantly increased thereafter. Our findings indicate that a coating material containing S-PRG fillers may prevent primary enamel demineralization.

Simulated cuspal deflection and flexural properties of high viscosity bulk-fill and conventional resin composites

OBJECTIVES

The purpose of this study was to investigate the simulated cuspal deflection and flexural properties of high viscosity bulk-fill and conventional resin composites.

METHODS

Seven high viscosity bulk-fill resin composites and eight conventional resin composites were used. Aluminum blocks (10 mm x 8 mm x 15 mm) with a mesio-occlusal-distal (MOD) cavity [4 (W) mm x 8 (L) mm x 4 (D) mm] were prepared and randomly divided into groups for different measurement techniques [micrometer vs CSLM] and further subdivided according to type of resin composite (high viscosity bulk-fill vs conventional resin composite). The simulated cuspal deflection resulting from the polymerization of resin composite bonded to a precisely machined MOD cavity within an aluminum block was measured with either a novel highly accurate submicron digimatic micrometer (MDH-25 M, Mitsutoyo, Tokyo, Japan) or a confocal laser scanning microscope (CLSM, VK-9710, Keyence, Tokyo, Japan) cuspal measurement method. In addition, flexural properties of tested resin composites were measured to investigate the relationship between simulated cuspal deflection and flexural properties. Scanning electron microscopy observation of tested resin composites was also conducted.

RESULTS

The simulated cuspal deflection of high viscosity bulk-fill resin composites was similar to that of conventional resin composites, regardless of measurement method. There were no statistically significant differences (p > 0.05) between the micrometer and CLSM cuspal measurement methods. There were statistically significant differences (p < 0.05) in flexural strength and elastic modulus depending on the material, regardless of the type of resin composite. Pearson correlation analysis did not show any statistically significant (p < 0.05) relationship between flexural properties and cuspal deflection.

CONCLUSIONS

The results of this study indicate that high viscosity bulk-fill resin composites show similar cuspal deflection with bulk-filling techniques, to those shown by conventional resin composites with incremental filling techniques. Simulated cuspal deflection can be measured using either a micrometer or CLSM, but this experiment failed to show any relationship between the flexural properties and simulated cuspal deflection of resin composites.

SIGNIFICANCE

High viscosity bulk-fill resin composites produce the same level of cuspal deflection as a conventional incrementally filled resin composite.

Wear of resin composites: Current insights into underlying mechanisms, evaluation methods and influential factors

The application of resin composites in dentistry has become increasingly widespread due to the increased aesthetic demands of patients, improvements in the formulation of resin composites, and the ability of these materials to bond to tooth structures, together with concerns about dental amalgam fillings. As resistance to wear is an important factor in determining the clinical success of resin composite restoratives, this review article defines what constitutes wear and describes the major underlying phenomena involved in this process. Insights are further included on both in vivo and in vitro tests used to determine the wear resistance of resin composite and the relationships between these tests. The discussion focuses on factors that contribute to the wear of resin composite. Finally, future perspectives are included on both clinical and laboratory tests and on the development of resin composite restorations.

Application of the Self- Assembling Peptide P11-4 for Prevention of Acidic Erosion

The aim of this study was to use ultrasonography to evaluate the effect of the self-assembling peptide P11-4 on acid erosion prevention. Curodont Repair (CR), which includes peptide P11-4, was used. Rectangular prisms of bovine enamel (4×1×1 mm) were immersed in pure orange juice for a period of 5 minutes six times per day for 28 days. These samples were divided into four groups of six specimens each and treated differently for an additional period of 28 days: 1) baseline group specimens were stored in artificial saliva; 2) CR group specimens were exposed to curodont without acid challenge; 3) NCRA (no curodont+acid challenge) specimens were treated with orange juice without curodont exposure; and 4) CRA (CR+acid challenge) specimens were treated with curodont before treatment with orange juice. The propagation time of longitudinal ultrasonic velocity (UV) was measured. Ultrastructural observation of each tested enamel surface was carried out using field-emission scanning electron microscopy (SEM). The UV data were analyzed using two-way analysis of variance with time and treatment as confounding factors. Post hoc pairwise tests among groups were performed using the Tukey honestly significant difference test. The average UV in intact bovine enamel for the baseline group ranged from 4,483 to 4,549 m/s and did not vary significantly within the test period. The average ultrasonic velocity (UV) in all samples decreased after the initial erosion. The UV in NCRA decreased further over time. Increased UVs were found for CR and CRA. For CR and CRA, there was no significant difference in UV at the end of the experiment from the initial value before erosion. In the results of SEM observation, the CR and CRA groups had similar morphologic features in that etching patterns were not clearly due to precipitation between the enamel rods. From the results of this in vitro study, it might be concluded that applying enamel matrix derivatives and self-assembling peptides on erosive lesions can improve remineralization.

Comparison of enamel bond fatigue durability of universal adhesives and two-step self-etch adhesives in self-etch mode

PURPOSE

To comparatively evaluate universal adhesives and two-step self-etch adhesives for enamel bond fatigue durability in self-etch mode.

METHODS

Three universal adhesives (Clearfil Universal Bond; G-Premio Bond; Scotchbond Universal Adhesive) and three two-step self-etch adhesives (Clearfil SE Bond; Clearfil SE Bond 2; OptiBond XTR) were used. The initial shear bond strength and shear fatigue strength of the adhesive to enamel in self-etch mode were determined.

RESULTS

The initial shear bond strengths of the universal adhesives to enamel in self-etch mode was significantly lower than those of two-step self-etch adhesives and initial shear bond strengths were not influenced by type of adhesive in each adhesive category. The shear fatigue strengths of universal adhesives to enamel in self-etch mode were significantly lower than that of Clearfil SE Bond and Clearfil SE Bond 2, but similar to that OptiBond XTR. Unlike two-step self-etch adhesives, the initial shear bond strength and shear fatigue strength of universal adhesives to enamel in self-etch mode was not influenced by the type of adhesive.

CLINICAL SIGNIFICANCE

This laboratory study showed that the enamel bond fatigue durability of universal adhesives was lower than Clearfil SE Bond and Clearfil SE Bond 2, similar to Optibond XTR, and was not influenced by type of adhesive, unlike two-step self-etch adhesives.

Corticotropin-releasing hormone receptor 1 antagonist blocks colonic hypersensitivity induced by a combination of inflammation and repetitive colorectal distension

Gastroenteritis is one of the risk factors for developing irritable bowel syndrome (IBS). However, the precise mechanism of postinfectious IBS is still unknown. We tested the hypothesis that a combination of previous inflammation and repetitive colorectal distention (CRD) makes the colon hypersensitive and that treatment with a corticotropin-releasing hormone receptor 1 (CRH-R1) antagonist blocks this colonic hypersensitivity. Rats were pretreated with vehicle or 2,4,6-trinitrobenzene sulphonic acid (TNBS) 6 weeks before CRD. For the CRD experiment, the colorectum was distended once a day for six consecutive days. The CRH-R1 antagonist (CP-154,526, 20 mg kg(-1)) or vehicle was injected subcutaneously 30 min before CRD. Visceral perception was quantified as visceromotor response (VMR) using an electromyograph. For histological examination, the rats were killed on the last day of CRD experiment, and haematoxylin and eosin-staining of colon segments was performed. Although from the first to the third day of CRD, VMRs increased in both the vehicle-treated rats and TNBS-treated rats, they were significantly higher in TNBS-treated rats than those in vehicle-treated controls. On the fifth day of CRD, however, VMRs in the vehicle-treated rats were significantly greater than those in TNBS-treated rats. Pretreatment of rats with CP-154,526 significantly attenuated the increase in VMR induced by repetitive CRD with previous inflammation. Finally, we found that repetitive CRD and repetitive CRD after colitis induced visceral inflammation. These results indicate that a combination of previous inflammation and repetitive CRD induces visceral hypersensitivity and that a CRH-R1 antagonist attenuates this response in rats.

Effect of active immunization against inhibin on hormonal concentrations and semen characteristics in Shiba bucks

Active immunization against inhibin increased ovulation rate in females; in males, the effects of active immunization against inhibin on hormonal concentrations and sperm production need more investigation. To test the hypothesis that active immunization against inhibin increases FSH secretion and sperm output, the present study was undertaken to determine the effects of active immunization against inhibin on hormonal profile and sperm production in Shiba bucks. The bucks were actively immunized against inhibin alpha-subunit (immunized group, n=6) or Freund adjuvant (control group, n=5) four times, at 5-weeks intervals. Blood samples were collected twice-weekly and two successive ejaculates of semen were collected (with an artificial vagina) once-weekly. Plasma concentrations of FSH, LH and testosterone were measured by radioimmunoassay (RIA) and sperm motility characteristics were measured by computer-assisted sperm analysis (CASA). All inhibin-immunized bucks produced antibodies against inhibin. Relative to control bucks, in immunized bucks there were significant increases in plasma FSH concentrations and in sperm concentrations from 5 to 9 weeks and from 8 to 11 weeks, respectively, after primary immunization. However, plasma concentrations of LH and testosterone, semen volume, percentage of motile spermatozoa and motility parameters (straight-line velocity, curvilinear velocity and linearity index) were similar in both groups. In conclusion, active immunization against inhibin alpha-subunit increased FSH secretions and enhanced sperm production in bucks, whereas LH and testosterone concentrations, semen volume and sperm motility parameters were unaffected. Active immunization against inhibin could be used to improve fertility in Shiba bucks.

Effects of passive immunization of goats against inhibin on follicular development, hormone profile and ovulation rate

This study was conducted to investigate the effect of immunoneutralization against endogenous inhibin on FSH secretion and ovulation rate, with the aim of developing a new superovulation method using inhibin antiserum in goats. Two groups of goats received an i.v. injection of either 10 ml normal goat serum (control; n = 6) or 10 ml inhibin antiserum developed against [Tyr(30)]-inhibin alpha (1-30) (n = 6) 48 h before treatment with prostaglandin F(2alpha) (PGF(2alpha)). Blood samples were collected at 6 h intervals and ovaries were examined each day using a B-mode ultrasound scanner equipped with a 7.5 MHz transducer during the experimental period. Immunization against inhibin resulted in a four- to fivefold increase (P < 0.01) in plasma concentrations of FSH. After luteolysis, plasma concentrations of oestradiol increased markedly to reach a preovulatory peak, which was about two times higher (P < 0.01) than that of the controls. The treatment was accompanied by a significant increase in the total number of follicles of > or = 3 mm in diameter at 24 (8.2 +/- 0.4 in inhibin antiserum group versus 4.8 +/- 0.3 in control group) and 96 h later (13.5 +/- 1.0 in inhibin antiserum group versus 5.3 +/- 0.6 in control group). The ovulation rate was significantly (P < 0.01) higher in goats treated with inhibin antiserum (4.2 +/- 0.5; n = 6) than in control goats (1.8 +/- 0.3; n = 6). These results indicate that inhibin is an important factor in the regulation of FSH secretion in goats and demonstrate that passive immunization against inhibin at 48 h before treatment with PGF(2alpha) induces the development of more follicles and increases ovulation rate. Thus, inhibin antiserum treatment may be an alternative to the use of exogenous gonadotrophins for induction of superovulation in goats.

Effects of passive immunization of goats against inhibin on follicular development, hormone profile and ovulation rate

This study was conducted to investigate the effect of immunoneutralization against endogenous inhibin on FSH secretion and ovulation rate, with the aim of developing a new superovulation method using inhibin antiserum in goats. Two groups of goats received an i.v. injection of either 10 ml normal goat serum (control; n = 6) or 10 ml inhibin antiserum developed against [Tyr(30)]-inhibin alpha (1-30) (n = 6) 48 h before treatment with prostaglandin F(2alpha) (PGF(2alpha)). Blood samples were collected at 6 h intervals and ovaries were examined each day using a B-mode ultrasound scanner equipped with a 7.5 MHz transducer during the experimental period. Immunization against inhibin resulted in a four- to fivefold increase (P < 0.01) in plasma concentrations of FSH. After luteolysis, plasma concentrations of oestradiol increased markedly to reach a preovulatory peak, which was about two times higher (P < 0.01) than that of the controls. The treatment was accompanied by a significant increase in the total number of follicles of > or = 3 mm in diameter at 24 (8.2 +/- 0.4 in inhibin antiserum group versus 4.8 +/- 0.3 in control group) and 96 h later (13.5 +/- 1.0 in inhibin antiserum group versus 5.3 +/- 0.6 in control group). The ovulation rate was significantly (P < 0.01) higher in goats treated with inhibin antiserum (4.2 +/- 0.5; n = 6) than in control goats (1.8 +/- 0.3; n = 6). These results indicate that inhibin is an important factor in the regulation of FSH secretion in goats and demonstrate that passive immunization against inhibin at 48 h before treatment with PGF(2alpha) induces the development of more follicles and increases ovulation rate. Thus, inhibin antiserum treatment may be an alternative to the use of exogenous gonadotrophins for induction of superovulation in goats.

Ovarian and hormonal response of female goats to active immunization against inhibin

This study was conducted to evaluate the effect of active immunization against inhibin on hormonal levels and the ovulation rate in goats. Ten adult Shiba goats (Capra hircus) in two groups were used in this study. The first group was injected with inhibin vaccine (immunized, n=5) and the second group was injected with Freund's adjuvant (control, n=5) followed by three booster injections at 4-week intervals. After the third booster injection, three consecutive periods of oestrus were induced using prostaglandin F(2alpha) at intervals of 11 days. Blood samples were collected at 2-6 h intervals and the ovaries were monitored using B-mode ultrasonography. All inhibin-immunized goats generated antibodies that bound (125)I-labelled bovine inhibin and their FSH concentrations were significantly higher than corresponding values in the control group. Also, inhibin-immunized goats had significantly higher preovulatory oestradiol-17beta (P<0.01) and higher concentrations of progesterone in the luteal phase (P<0.05). Immunization of goats against inhibin resulted in a significant (P<0.01) increase in ovulation rate (control: 1.7+/-0.3 vs immunized: 7.6+/-1.1). These results demonstrate that active immunization against inhibin enhances ovarian follicular development and ovulation rate by promoting an increase in pituitary FSH secretion. Therefore, immunization against inhibin may be a useful alternative to the conventional approach of superovulation in goats.

Relationship between insulin resistance and uremic toxins in the gastrointestinal tract

The relationship between insulin resistance and local uremic toxins was examined using an oral adsorbent. Fourteen rats demonstrating a diabetic state underwent two-thirds, nephrectomy and were divided into two groups. The control group was fed standard rat chow, and the test group was fed standard rat chow containing 5% AST-120. The target level of blood glucose was achieved by controlling the dosage of exogenous insulin. All rats were sacrificed at week 6. Body weight, blood glucose level, and renal function at week 6 were not significantly different between both groups. However, the mean blood glucose level and the mean dose of exogenous insulin in the AST-120-fed group were significantly reduced as compared with the control group. The results of the present study indicate that administration of an oral adsorbent in diabetic nephropathy decreases the doses of exogenous insulin and improves insulin resistance, and that uremic toxins which exist in the gastrointestinal tract play important roles.

Intravascular ultrasound imaging before and after angioplasty for stenosis of arteriovenous fistulae in haemodialysis patients

BACKGROUND

Complications of haemodialysis vascular access have emerged as a major cause of patient morbidity. Intravascular ultrasound imaging is a new technical modality providing visualization of the vessel lumen and wall structure in a cross-sectional fashion. Percutaneous transluminal angioplasty has long been used in the treatment of stenoses of arteriovenous fistulae. However, there is no detailed quantitative information on the stenotic lesion and the morphological change by angioplasty.

METHODS

Intravascular ultrasound studies were performed in 40 haemodialysis patients with 63 stenoses in arteriovenous fistulae who had percutaneous transluminal angioplasty. The patients were qualitatively and quantitatively evaluated for echogenic patterns and morphological changes before and after angioplasty.

RESULTS

Morphological plaque features in stenotic lesions were classified as 37 soft (58%), five hard (8%), 20 mixed (32%), and one calcified sites. Plaque fractures after angioplasty were detected in 45/63 (71%) instances. The lumen cross-sectional area was found to be dilated approximately threefold (from 3.8+/-2.4 to 11.1+/-4.5 mm(2)) and the external elastic membrane cross-sectional area was dilated approximately twofold (from 11.1+/-5.3 to 19.8+/-8.1 mm(2)) after angioplasty.

CONCLUSION

These results indicate that intravascular ultrasound allows both qualitative and quantitative assessments of arteriovenous fistulae in haemodialysis patients. The results further suggest that the mechanism of expansion of arteriovenous fistulae stenoses by percutaneous transluminal angioplasty involves stretching of the vessel wall as well as plaque fractures.

[Phosphate kinetics in patients on chronic hemodialysis]

To investigate the phosphate kinetics in hemodialysis (HD), 8 patients in a stable condition, who were receiving HD three times a week for 4 hours per session, were investigated. Plasma phosphate was under 7 mg/dl, and residual renal function had almost disappeared. Dialysate containing phosphate was prepared by adding Na2HPO4 using a micro-infusion pump from the inlet of single pass dialysate in the individual dialysate delivery system. In the first week, Na2HPO4 was not added as the control period. In the second session of the second and third week, Na2HPO4 was added to give a phosphate concentration of 1.0 and 2.0 mmol/l in the dialysate, respectively. Total phosphate mass removal was 777 +/- 46.64 mg in the control period, 403 +/- 67.21 mg in the second week, and -230 +/- 214.8 mg in the third week. Total phosphate mass removal in the second and third week was significantly lower than that of the control period. Plasma phosphate concentration was significantly decreased after the HD compared with before the HD in the control and second week. There was no significant difference in plasma phosphate concentration between the period before HD and at 48 hours in the control and the second week. Plasma phosphate concentration before HD not only depended on phosphate mass removal by HD, but also on other factors. We suggest that dialysate containing phosphate might prevent excessive phosphate removal from non-extracellular compartments during HD.

[A consideration in the care of elderly patients receiving home hospice care: administration of parenteral nutrition at home]

Due to the recent increase in the elderly population in Japan, the number of elderly patients with gastric cancer has also increased. As a result, not only the need for care of these patients has increased but also the care system has become diverse. In our hospital, more than 30% of patients who received home hospice care were over 70 years old and home hospice care of elderly patients with terminal cancer has become an important activity of our hospital. Whether home parenteral nutrition (HPN) procedures should be administered in the home for these patients is controversial. Our hospital has decided to inform patients with malignant disease of their true diagnosis under the doctrine of informed consent. In 1997, 94.1% of patients above 70 years, of age were informed of the actual nature of their disease. As a result, they were allowed to make a choice regarding home hospice care. An 81-year-old patient with terminal gastric cancer chose home hospice care and successfully managed the treatment procedures, including the use of a pump for intravenous alimentation. Through this case, we report here an ideal model of home hospice care of elderly patients under the concept of informed consent.

[The influence of correction of acidosis on plasma level of branched-chain amino acids in chronic hemodialysis patients]

Seven patients undergoing chronic hemodialysis three times a week and whose plasma bicarbonate concentration on predialysis was consistently under 18 mmol/l due to bicarbonate dialysis (BCD), were treated with BCD for 2 weeks, then switched to acetate-free biofiltration (AFB) for 8 weeks. In both periods, the same high flux dialyzer (AN69HF) was used. The treatment time, dialysate flow rate and blood flow rate were kept constant in each patient during both periods. Plasma bicarbonate concentration (HCO3-), serum urea nitrogen (SUN), serum creatinine (Cr) and plasma amino acids concentrations (AA) were measured before dialysis and KT/V was calculated on the 2nd days of the last week in both periods. HCO3- on AFB was significantly higher than that on BCD (16.4 +/- 0.9 vs 19.9 +/- 1.8 mmol/l; p < 0.05). SUN on AFB was significantly lower than that on BCD even though the dialysis schedule and dietary content were not changed (84.7 +/- 3.7 vs 76.6 +/- 3.8 mg/dl; p < 0.05). TP, Cr and KT/V were not significantly different. Plasma total amino acid concentration (TAA) and plasma essential amino acid concentration (EAA) were not significantly different in both periods. In contrast, plasma branched-chain amino acid concentrations (BCAA) on AFB were significantly higher than that on BCD (313.5 +/- 44.3 vs 390.3 +/- 50.7 mumol/l; p < 0.05). Plasma BCAA concentrations, valine (VAL), leucine (LEU) and isoleucine (ILE), were significantly higher on AFB than that on BCD, respectively (p < 0.05). These findings suggest that optimal correction of the metabolic acidosis in chronic hemodialysis patients by AFB leads to a significant increase in plasma BCAA concentration.

Analysis of mandible of newly developing strain of Japanese white rabbit (Nib:JWNS)

In the present paper, we applied analysis of the mandible to a new strain of Japanese White rabbit being developed (Nib: JWNS), at 5th and 8th generations (F5 and F8), and evaluated the process of establishment, making comparison with the parent colonies (I, K and L), and other established JW colonies (A, E, O and R). The mandibles were measured at 12 sites and the data obtained were calculated by principal component analysis and discriminant analysis. As a result of principal component analysis, the parent colonies were found to be close to one another with intermediate size of the mandible and height of condyloid and angular processes, but in F5 and F8 the mandibles were slightly shorter in height and different from those in the parent colonies. On the other hand, results of discriminant analysis revealed that mandibles were discriminated correctly 100% in colonies A, O and R, and 90% in E and I. Colonies A, O, R, E and I were therefore regarded as established strains. In the developing colonies, the discriminant rate was 70% in F5 and 80% in F8. One mandible from F5 and two from F8 were wrongly classified to the parent colony L, which was the lowest discriminant rate among the colonies examined (61.5%). The results of both statistical analyses suggest that the JWNS are almost established at 8th generation as a new strain.

Effects of recombinant human erythropoietin (rHuEPO) on nutritional status of hemodialysis patients: investigation of direct anabolic effects of rHuEPO

To investigate whether the nutritional improvement achieved by recombinant human erythropoietin (rHuEPO) treatment is the result of anemia correction with rHuEPO or the direct anabolic effects of rHuEPO per se, nutritional assessment was performed in 2 studies (study I and II) on hemodialysis (HD) patients. Nutritional assessment included blood biochemistry determinations, anthropometric measurements, daily protein intake (DPI) and dialysis efficiency. In study I, 5 HD patients who had not been given rHuEPO and had a hematocrit (Hct) of < or = 25%, were administered rHuEPO at the initial dose of 96.2 U/kgBW. Nutritional assessment of these patients was performed before rHuEPO treatment and every 4 weeks until the 24th week after rHuEPO treatment. In study II, the same nutritional assessment as in study I except for DPI, was performed in 2 groups with the same Hct level and dialysis regimen; an EPO group (n = 8) previously given rHuEPO (88.2 +/- 13.7 U/kgBW, 25.8 +/- 2.5 mos) and a non-EPO group (n = 8) not given rHuEPO. In study I, the mean Hct level was significantly increased 4 weeks after rHuEPO treatment (23.3 +/- 0.6 to 26.9 +/- 0.9%). However, the nutritional parameters and dialysis efficiency were nearly constant over 24 weeks, suggesting either the absence of a short-term direct anabolic effect of rHuEPO or masking of such an effect due to general condition improvement by anemia correction with rHuEPO. In study II, no significant differences in nutritional assessment were confirmed between the groups, suggesting that a long-term direct anabolic effect of rHuEPO may not exist and nutritional improvement may result from correction of anemia with rHuEPO.(ABSTRACT TRUNCATED AT 250 WORDS)

Oral 1,25(OH)2D3 pulse therapy for the treatment of secondary hyperparathyroidism

We examined the effect of oral 1,25(OH)2D3 pulse therapy in hemodialyzed patients with secondary hyperparthyroidism (2 degrees HPT). Prescription of 6.0 micrograms 1,25(OH)2D3 once a week combined with calcium carbonate as a phosphate binder during the last 5 days a week for 12 weeks resulted in improvement of mild to moderate 2 degrees HPT despite no significant differences in serum total calcium and phosphate concentration. In addition, the effect was greater in cases with mild 2 degrees HPT. A single administration of 6 micrograms 1,25(OH)2D3 reduced the parathyroid hormone concentration in patients with mild 2 degrees HPT or with a short duration of hemodialysis. Tmax of the serum 1,25(OH)2D3 after single administration of 6.0 micrograms 1,25(OH)2D3 was individually different (range, 0.4-20.9 hrs). It is recommended that early employment of oral 1,25(OH)2D3 pulse therapy be undertaken once a week combined with prescription of calcium salt as a phosphate binder during the last 5 days a week for the treatment of 2 degrees HPT refractory to conventional therapy, since there is no risk of aluminum accumulation with satisfactory control of the serum total calcium and phosphate concentration.

A case complicated with SLE during maintenance hemodialysis

A 40-year-old woman suffered from toxemia of pregnancy in 1977 and was admitted to hospital. Thereafter, she developed nephrotic syndrome, underwent a renal biopsy, and a diagnosis of membranoproliferative glomerulonephritis (MPGN) was made. She received steroid therapy, immunosuppressive drug and anticoagulant therapy, and recovered sufficiently to be discharged from hospital in April, 1979. During subsequent ambulatory treatment at our outpatient department, her renal function deteriorated gradually, and maintenance hemodialysis was started from June, 1990. In July, 1991, she was admitted to our hospital with pleurisy and pericarditis. There was no improvement despite antibiotic treatments. Laboratory data revealed leukopenia and lymphopenia. Under suspicion of systemic lupus erythematosus (SLE), relevant tests were carried out. Immunological abnormalities such as positive LE cells and the presence of various autoantibodies, together with clinical signs of hypersensitivity to sunlight, stomatitis and serositis, satisfied the diagnostic criteria of the ARA and a diagnosis of SLE was made. This case did not exhibit any clinical or serological abnormalities except for the renal disorder for a 10-year period after the histological diagnosis of MPGN, but was eventually diagnosed as SLE as a result of the manifestation of SLE symptoms for the first time after one year of maintenance hemodialysis. Immunological abnormalities and SLE during maintenance hemodialysis are discussed in relation to other reports.

How long can continuous ambulatory peritoneal dialysis be continued?

We investigated how long continuous ambulatory peritoneal dialysis (CAPD) could be continued in the face of peritoneal sclerosis. 15 CAPD patients with no experience of peritonitis were selected and the time limitation for CAPD was examined retrospectively, based on the dialysate osmolality, serum creatinine concentration, etc.. The values for the dialysate osmolality and serum creatinine concentration increased gradually with the duration of CAPD and were significantly increased from 6 months. 5 patients whose serum creatinine concentration during the first 6 months after initiation of CAPD increased more than 5 mg/dl, could not continue CAPD for more than 24 months because of the appearance of peritoneal membrane failure. When the time limitation for CAPD was assessed in 10 stable patients, close relationships between the mean dialysate osmolality and duration of CAPD (Y = 0.52X + 351.25, r = 0.83, P < 0.01), and between the mean serum creatinine concentration and duration of CAPD (Y = 0.18X + 6.84, r = 0.95, P < 0.001) were recognized. If the practical limitation for CAPD was set at 400 mOsm/l in terms of the dialysate osmolality or 20 mg/dl in terms of serum creatinine concentration, its value became 94.1 months or 73.1 months, respectively. It is concluded that the time limitation for CAPD can be expected to be approximately 6 to 8 years in stable CAPD patients, and we need to resolve CAPD-induced problems involving the peritoneal membrane in order to continue CAPD for more than 10 years.

Early morphological changes of tubules in rats with chronic renal failure

We investigated the early changes of tubules and effect of the oral adsorbent, AST-120, on the early changes of tubules in rats with chronic renal failure. Sprague-Dawley rats were divided into two groups with and without AST-120, after 3/4 nephrectomy. Although there were no significant differences in levels of blood urea nitrogen, serum creatinine, creatinine clearance, inulin clearance, para-aminohippuric acid clearance and urinary N-acetyl-beta-D-glucosaminidase at week 8 between the two groups, the amount of 24-hour urinary protein excretion and the direct systolic blood pressure at week 8 were significantly decreased in the group with AST-120. Examinations by light microscopy at week 8 revealed that proteinaceous casts in the tubules, tubular dilatation and infiltration of monocytes into the interstitium in the group with AST-120 were less prominent than those in the group without AST-120. A significant difference in numbers of proteinaceous casts was noted at week 8 between the two groups. In rats with chronic renal failure at the early stage, it is concluded that the formation of proteinaceous casts, resulting in tubular damage, is increased and that AST-120 delays the occurrence of proteinaceous casts by delaying the increase in urinary protein excretion.

A case of primary systemic amyloidosis with AA protein

We present here a case of young adult-onset primary systemic amyloidosis with AA protein. A 29-year-old male presenting with macrohematuria was transferred to our hospital because of aggravation of renal function. Amyloid protein was detected in the bladder, stomach and thyroid. The amyloid protein proved to be AA type by potassium permanganate histochemical analysis. Since secondary amyloidosis was excluded by the laboratory data and there was no family history of amyloidosis, a diagnosis of primary systemic amyloidosis with AA protein was reached. Although the patient was prescribed dimethyl sulphoxide, his renal function worsened with gastrocolic symptoms and a bleeding tendency. Hemodialysis (HD) was then initiated. After starting the HD, the patient's general condition recovered and subsequently the patient on treatment with maintenance HD was discharged.

Pharmacokinetics and optimum dose of disopyramide in patients with chronic renal failure

The pharmacokinetics and optimum dose for maintenance of disopyramide (DP) which is effective against arrhythmia were studied in patients with chronic renal failure (CRF, n = 10), who had a creatinine clearance (Ccr) less than 30 ml/min. The plasma concentrations (PC) of DP and mono-isopropyl-disopyramide (MDP) an active metabolite of DP, were measured by high performance liquid chromatography. Samples from patients and controls were obtained at 0, 1, 2, 3, 4, 6, 8, 12, 24, 33, and 48 hr after oral administration (OA) of 100 mg DP. The pharmacokinetic parameters were calculated using a two-compartment model. In CRF, the plasma half life (T 1/2) of DP was 5.25 to 22.42 hr (average is 12.45 hr) and that of MDP was 5.09 to 131.66 hr (average is 16.9 hr). In normal controls, the T 1/2 of DP was 6.05 hr, but that of MDP could not be determined the available sensitivity of measurement. T max was 3.11 hr at the total PC of DP and MDP, and C max was 2.48 g/ml on average. In conclusion, the present study revealed that: (1) the PC of a mixture of DP and MDP should rise following OA of DP every 8 or 12 hr in CRF; (2) it is necessary therefore to monitor the accumulation of MDP after rolling OA of DP; and (3) OA of DP every 24 hr can maintain an effective PC.

Three-quarters nephrectomy in rats as a model of early renal failure

To produce a compatible model of early renal failure easily, we prepared three-quarters nephrectomized animal. 20 Sprague-Dawley rats were divided into the following two groups: 10 rats which received three-quarters nephrectomy (Nx group), assuming the weight of both kidneys to be equal, and another 10 rats which underwent sham operations (S group). The levels of creatinine clearance in Nx group and S group were 286.5 +/- 33.5 vs. 431.1 +/- 55.9 microliters/min/100 g BW (P less than 0.001) on week 2, and 233.0 +/- 16.7 vs. 562.3 +/- 62.9 microliters/min/100 g BW (P less than 0.001) on week 10, respectively. The indirect and direct systolic blood pressure (SBP) values of Nx group and S group at the 10th week were 154.5 +/- 5.5 vs. 131.1 +/- 3.6 mmHg (P less than 0.01), and 148.2 +/- 4.8 vs. 130.7 +/- 6.6 mmHg (P less than 0.01), respectively. Significant changes in the levels of urinary protein excretion, urinary sodium output, urinary epinephrine, urinary norepinephrine and plasma renin activity between both groups were recognized on the 10th week. The planar area of Nx group was significantly increased as compared to that of S group (11.0 +/- 0.3 vs. 7.2 +/- 0.1 x 10(-3) mm2, P less than 0.001). It is concluded that this model resembles early renal failure in humans because slow progression of renal dysfunction occurred with mild elevation of SBP, and that it is adequate for evaluating the influence of glomerular hypertrophy, resulting in glomerulosclerosis.

Treatment of secondary hyperparathyroidism in patients on maintenance hemodialysis

The effects of CaCO3 were investigated in 7 patients undergoing maintenance hemodialysis who had been treated with 1 microgram/day 1 alpha (OH)D3 and 2 g/day Al(OH)3. CaCO3 (3 g/day) was administered instead of Al(OH)3. The levels of serum total calcium and ionized calcium were significantly increased, the level of C-terminal parathyroid hormone was appreciably decreased and the levels of serum aluminum in all patients were reduced. There were no significant changes in the levels of serum phosphate, calcium x phosphate product, alkaline phosphatase, calcitonin, magnesium and bicarbonate. It is concluded that 3 g/day CaCO3 is equivalent to 2 g/day Al(OH)3 in terms of its phosphate-binding effect, and the prescription of CaCO3 together with 1 alpha (OH)D3 ameliorates secondary hyperparathyroidism.

Influence of 1 alpha-hydroxy vitamin D3 (0.25 micrograms/day) and calcium carbonate on patients with chronic renal failure at the predialytic stage

The influence of a small amount of 1 alpha (OH)D3 on patients with chronic renal failure at the predialytic stage (CRFPS patients) receiving CaCO3 was investigated. 7 patients given CaCO3 (3 g/day) were administered 1 alpha (OH)D3 (0.25 micrograms/day) over a period of 12 weeks. 2 patients were eliminated from the study because of obvious deterioration of renal function. The others revealed no significant changes in levels of serum creatinine, adjusted calcium, phosphate, calcium x phosphate product, alkaline phosphatase, C-terminal parathyroid hormone, pH and bicarbonate. Our results indicated that even 0.25 micrograms/day 1 alpha (OH)D3 should not be prescribed to CRFPS patients given 3 g/day CaCO3. We recommend a little sole use of CaCO3 in CRFPS patients, paying attention to any exacerbation of renal function due to a rise in serum calcium concentration, when therapy for secondary hyperparathyroidism is required.

Influence of cefotaxime on renal function during the treatment of infections

A study was conducted of the effects of cefotaxime, a third generation cephalosporin antibiotic, on the function of the kidney, using several indices of renal function including urinary concentrations of the renal enzyme N-acetyl-beta-D-glucosaminidase (NAG). In 6 patients with respiratory infections and normal renal function (group I), the urinary concentrations of NAG before and after the administration of cefotaxime 2 to 4g daily were 5.7 +/- 0.6 U/L and 5.5 +/- 0.9 U/L, respectively (NS). Similarly, 9 patients with chronic renal failure who were not undergoing haemodialysis showed pre- and post-treatment urinary NAG concentrations of 8.7 +/- 4.0 U/L and 6.6 +/- 1.7 U/L, respectively (NS), while the corresponding values in 12 renally impaired patients undergoing haemodialysis (group III) were 8.1 +/- 3.5 U/L and 8.9 +/- 3.8 U/L, respectively (NS). With regard to other parameters of renal function (serum creatinine, BUN, beta 2M, and creatinine clearance), no statistically significant differences were found between the values obtained before and after therapy with cefotaxime. Therefore, it was concluded that the influence of cefotaxime on renal function is slight, and that this antibiotic can be safely used to treat patients with infections in the presence of renal dysfunction.