Swallowing disorders and 1-year functional decline in community-dwelling older adults receiving home care.

The purpose of this study was to clarify the effect of swallowing disorders on functional decline in community-dwelling older adults receiving home care. This was a 1-year follow-up survey of 176 individuals ≥60 years living at home and receiving homecare services, without total dependence in basic daily living activities, in two mid-sized municipalities in Fukuoka, Japan. Functional decline was measured using the Barthel index (BI), and the primary outcome was total dependence in basic daily living activities (BI ≤ 20 points). Swallowing function was assessed using cervical auscultation, and the primary predictor was swallowing disorders. Logistic regression models were used to assess univariate and multivariate associations between baseline swallowing function and functional decline during follow-up. During follow-up 16 (9.1%), the participants became totally dependent in basic daily living activities. The participants with swallowing disorders had 6.41 times higher odds of total dependence in basic daily living activities compared to participants with normal swallowing function. After adjusting for potential confounders, swallowing disorders were significantly associated with higher odds of total dependence in basic daily living activities (odds ratio = 5.21, 95% confidence interval = 1.33-20.44). Regarding swallowing disorders, the corresponding population attributable fraction (%) of the incidence of total dependence in basic daily living activities was 50.4%. The current findings demonstrated that swallowing disorders were associated with greater risk of functional decline in basic daily living activities among older adults living at home and receiving home nursing care. Maintenance and improvement of swallowing function may prevent late-life functional decline.

Swallowing Function and Nutritional Status in Japanese Elderly People Receiving Home-care Services: A 1-year Longitudinal Study.

OBJECTIVES: Malnutrition is a serious health concern for frail elderly people. Poor oral function leading to insufficient food intake can contribute to the development of malnutrition. In the present study, we explored the longitudinal association of malnutrition with oral function, including oral health status and swallowing function, in elderly people receiving home nursing care. DESIGN: Prospective observational cohort study with 1-year follow-up. SETTING: Two mid-sized cities in Fukuoka, Japan from November 2010 to March 2012. PARTICIPANTS: One hundred and ninety-seven individuals, aged ≥ 60 years, living at home and receiving home-care services because of physical disabilities, without malnutrition. MEASUREMENTS: Oral health status, swallowing function, taking modified-texture diets such as minced or pureed foods, nutritional status, cognitive function, and activities of daily living were assessed at baseline. The associations between malnutrition at 1-year follow-up and these related factors were analyzed using a logistic regression model. RESULTS: Swallowing disorders [risk ratio (RR): 5.21, 95% confidence interval (95% CI): 1.65-16.43] were associated with malnutrition. On the other hand, oral health status did not have a direct association with malnutrition. CONCLUSION: Swallowing disorders may be associated with the incidence of malnutrition in elderly people receiving home-care. The findings indicate that maintaining swallowing function may contribute to the prevention of malnutrition in frail elderly people.

Screening for Malnutrition in Community Dwelling Older Japanese: Preliminary Development and Evaluation of the Japanese Nutritional Risk Screening Tool (NRST).

BACKGROUND: Early and effective screening for age-related malnutrition is an essential part of providing optimal nutritional care to older populations. OBJECTIVE: This study was performed to evaluate the adaptation of the original SCREEN II questionnaire (Seniors in the Community: Risk Evaluation for Eating and Nutrition, version II) for use in Japan by examining its measurement properties and ability to predict nutritional risk and sarcopenia in community-dwelling older Japanese people. The ultimate objective of this preliminary validation study is to develop a license granted full Japanese version of the SCREEN II. PARTICIPANTS: The measurement properties and predictive validity of the NRST were examined in this cross-sectional study of 1921 community-dwelling older Japanese people. MEASUREMENTS: Assessments included medical history, and anthropometric and serum albumin measurements. Questions on dietary habits that corresponded to the original SCREEN II were applied to Nutritional Risk Screening Tool (NRST) scoring system. Nutritional risk was assessed by the Geriatric Nutrition Risk Index (GNRI) and the short form of the Mini-Nutritional Assessment (MNA-SF). Sarcopenia was diagnosed according to the criteria of the European Working Group on Sarcopenia in Older People. RESULTS: The nutritional risk prevalences determined by the GNRI and MNA-SF were 5.6% and 34.7%, respectively. The prevalence of sarcopenia was 13.3%. Mean NRST scores were significantly lower in the nutritionally at-risk than in the well-nourished groups. Concurrent validity analysis showed significant correlations between NRST scores and both nutritional risk parameters (GNRI or MNA-SF) and sarcopenia. The areas under the receiver operating characteristic curves (AUC) of NRST for the prediction of nutritional risk were 0.635 and 0.584 as assessed by GNRI and MNA-SF, respectively. AUCs for the prediction of sarcopenia were 0.602 (NRST), 0.655 (age-integrated NRST), and 0.676 (age and BMI-integrated NRST). CONCLUSIONS: These results indicate that the NRST is a promising screening tool for the prediction of malnutrition and sarcopenia in community-dwelling older Japanese people. Further development of a full Japanese version of the SCREEN II is indicated.

Videoendoscopic assessment of swallowing function to predict the future incidence of pneumonia of the elderly.

The purpose of the present study was to examine what dysphagic signs identified by videoendoscopy (VE) could predict the incidence of pneumonia and body weight loss in elderly patients living in nursing homes. This study was performed at six nursing care facilities in Japan from March 2007 to February 2009. The 148 subjects (85·1 ± 8·0 years, male/female: 43/105) were evaluated for their feeding and swallowing movements by clinical and VE examinations during the consumption of a regular meal. The VE examination items included the existence/absence of pharyngeal residue, laryngeal penetration, and aspiration of food and saliva. The patients were followed-up for 3 months with individualized feeding therapy based on the results of the clinical/VE examination at baseline, and the incidence of pneumonia was examined as the primary outcome. In patients without pneumonia, the body weight change was also measured as a secondary outcome. The risk factors for pneumonia and body weight loss (of 3% or more) were identified among the clinical/VE examination items by a Cox proportional hazard analysis. Even with elaborative feeding therapy, 12 (8·1%) of the 148 patients developed pneumonia during the 3 months follow-up period. The existence of signs of 'silent aspiration of saliva' or 'aspiration of saliva' detected by VE examination was a significant risk factor for both pneumonia and a body weight loss of 3% or more. This study shows that 'aspiration of saliva' detected by VE is a significant risk factor for both pneumonia and body weight loss in elderly patients living in nursing homes.

Development of rapid oral bacteria detection apparatus based on dielectrophoretic impedance measurement method.

In this study, a bacteria detection apparatus based on dielectrophoretic impedance measurement (DEPIM) method was demonstrated for rapid evaluation of oral hygiene. The authors integrated a micro electrode chip on which bacteria were captured by dielectrophoresis (DEP), an AC voltage source to induce DEP force, and an impedance measurement circuit to a portable instrument that enables rapid and automated oral bacterial inspection in hospitals and clinics. Special considerations have been made on effects of high electrical conductivity of oral samples on DEP force and DEPIM results. It was shown experimentally and theoretically that using a higher electric field frequency for the DEP bacteria trap and the impedance measurement could realise DEPIM application to bacteria inspection from oral samples with higher conductivity. Based on these investigations, the authors optimised the frequency condition of the DEPIM suitable for inspecting an oral sample along with the design and development of a portable DEPIM apparatus for on-site inspection of oral bacteria. Under the optimised frequency condition, DEPIM results were in good agreement with the conventional culture method showing significant applicability of the DEPIM apparatus for practical rapid oral bacteria inspection.

Lip closing pressure and spoon management in passive spoon feeding.

To determine the sources of lip closing pressure (P(LC) ) generation during passive spoon feeding, we used a fine pressure transducer glued into a wooden spoon, as well as electromyography (EMG) of the upper and lower lips and the submental muscle complex, in normal adult volunteers (average age 24·5 years). An assistant fed a seated subject 0·6 mL of yogurt and then withdrew the spoon from the subject's closed mouth. The spoon was held at an angle of 0° (i.e. in the naso-auricular plane) during serving and at either 0° or 60° during withdrawal. We detected simultaneous increases in P(LC) and in EMG activity in the lips and the submental muscle complex. The maximum P(LC) was significantly higher at 60° [65 ± 11 g cm(-2) (mean ± s.e.m)] than at 0° (42 ± 8 g cm(-2)). The former was correlated with the maximum EMG amplitude, which was analysed by using the mean of the root-mean-square EMG and presented as a percentage of the maximum EMG obtained in the lower lip region and the submental muscle complex during subsequent swallowing in each subject. In conclusion, in healthy adult subjects, perioral muscles of the lower lip region and the submental muscle complex participate in P(LC) generation, particularly at a steep spoon withdrawal angle. The results suggest that a steep withdrawal angle not only increases P(LC) but also promotes these muscles' activities in passive spoon feeding.

[Restoration of the habit of routine tooth brushing teeth in patients with severe dementia].

Purpose-related activities are often lost in severe dementia, including oral hygiene habits such as brushing teeth. The aim of this study is to investigate whether patients with severe dementia can be induced to develop an oral hygiene routine through an occupational therapy approach and whether routine training in oral hygiene habits can reduce dental or denture plaque. Six female inpatients in the same room, who had been given diagnosis of multiple cerebral infarction and dementia. The project design included 4 periods a, b1, b2, and c, a and c were observation periods, while b1 and b2 were general approach periods. In the approach periods we held meetings, and made the program for oral hygiene, planning and problem-solving. In the b2 period both direct intervention by the dentists, dental hygienists and occupational therapists reinforced the habit of brushing teeth in subjects and educated care approach guidance. No patient completely resumed routine habit of brushing teeth, but an improvement in brushings was found in four subjects, one case had no change, and in one case brushing deteriorated. The state of oral hygiene showed improvement in periods b1 and b2. Although the adherence of dental plaque decreased in period b2, it increased in period c. Despite the improvement in performance, sufficient improvement in oral disease prophylaxis was not recognized, suggesting the necessity of professional oral health care by dental staff, and of a disciplinary team approach.

Alumina powder/Bis-GMA composite: effect of filler content on mechanical properties and osteoconductivity.

Three composites consisting of alumina powder dispersed in a bisphenol-a-glycidyl methacrylate (Bis-GMA) matrix were prepared and evaluated to assess the effect of alumina powder content on the mechanical properties and osteoconductivity of the composite. The alumina powder composites (APC) consisted of alumina powder (AL-P) as the inorganic filler dispersed in a Bis-GMA matrix that was solidified by a radical polymerization process. Prior to polymerization the AL-P was mixed with the monomers in proportions of 50%, 70%, and 80% by weight (APC50, APC70, and APC80). A fused silica-glass-filled composite containing 70% glass by weight (SGC70) was used as a control. The compressive and bending strengths, the elastic modulus in bending, and the bending strain of the composites increased as the AL-P content increased. We also evaluated the composites in vivo by implanting them into the medullary canals of rat tibiae. To compare the osteoconductivity of the composites, an affinity index was calculated for each composite; the affinity index equals the length of a bone in direct apposition to the composite and is expressed as a percentage of the total length of the composite surface. Microradiographic examination for periods of up to 26 weeks after implantation revealed that APC50, APC70, and APC80 all exhibited excellent osteoconductivity and made direct contact with the bone with no interposed soft tissues. However, the higher the AL-P content of the composite, the higher the osteoconductivity, especially at 4 weeks after the operation. Moreover, the amount of bone directly apposed to the composite surface increased with time. In contrast, little bone formation was seen on the surface of SGC70, even after 26 weeks. Observation by scanning electron microscope-energy dispersive X-ray microanalysis demonstrated that bone made direct contact with the APC surface through a layer containing calcium, phosphorus, and alumina powder. These results suggest that APC shows promise as a basis for developing mechanically strong and highly osteoconductive composites.

Effect of bioactive filler content on mechanical properties and osteoconductivity of bioactive bone cement.

We took three types of bioactive bone cement (designated AWC, HAC, and TCPC), each with a different bioactive filler, and evaluated the influence of each filler on the mechanical properties and osteoconductivity of the cement. The cements consisted of bisphenol-a-glycidyl methacrylate-based (Bis-GMA based) monomers as an organic matrix, with a bioactive filler of apatite/wollastonite containing glass-ceramic (AW-GC) or sintered hydroxyapatite (HA) or beta-tricalcium phosphate (beta-TCP) powder. Each filler was mixed with the monomers in proportions of 50, 70, and 80% (w/w), giving a total of nine cement subgroups. The nine subgroups were designated AWC50, AWC70, AWC80, HAC50, HAC70, HAC80, TCPC50, TCPC70, and TCPC80. The compressive and bending strengths of AWC were found to be higher than those of HAC and TCPC for all bioactive filler contents. We also evaluated the cements in vivo by packing them into the intramedullary canals of rat tibiae. To compare the osteoconductivity of the cements, an affinity index was calculated for each cement; it equaled the length of bone in direct apposition to the cement, expressed as a percentage of the total length of the cement surface. Microradiographic examination up to 26 weeks after implantation revealed that AWC showed a higher affinity index than HAC and TCPC for each filler content although the affinity indices of all nine subgroups (especially the AWC and HAC subgroups) increased with time. New bone had formed along the AWC surface within 4 weeks, even in the cement containing AW-GC filler at only 50% (w/w); observation of the cement-bone interfaces using a scanning electron microscope showed that all the cements had directly contacted the bone. At 4 weeks the AWC had bonded to the bone via a 10 micron-thick reactive layer; the width of the layer, in which partly degraded AW-GC particles were seen, became slightly thicker with time. On the other hand, in the HAC- and TCPC-implanted tibiae, some particles on the cement surface were surrounded by new bone and partly absorbed or degraded. The results suggest that the stronger bonding between the inorganic filler and the organic matrix in the AWC cements gave them better mechanical properties. The results also indicate that the higher osteoconductivity of AWC was caused by the higher reactivity of the AW-GC powder on the cement surface.

Osteoconductivity and bone-bonding strength of high- and low-viscous bioactive bone cements.

A study was conducted to evaluate the osteoconductivity and bone-bonding ability of two types of bioactive bone cement, both consisting of apatite and wollastonite containing glass-ceramic powder (AW-P), fused silica glass powder (SG-P), submicron fumed silica as an inorganic filler, and bisphenol-a-glycidyl methacrylate (Bis-GMA) based resin as an organic matrix. The cements had two kinds of formulas: one (dough-type cement; designated DTC) composed of 85% (w/w) filler and 15% resin, which was developed for fixation of the acetabular component in total hip arthroplasty and could be handled manually; and one (injection-type cement; designated ITC) composed of 79% (w/w) filler and 21% resin. ITC was developed for fixation of the femoral component and, because it had a lower viscosity than DTC, could be injected. The DTC and ITC both contained 73% AW-P, 25% SG-P, and 2% fumed silica in the weight ratio of the filler component. Two other types of cement, both of which consisted of 83.3% AW-P or SG-P, 1.7% fumed silica, and 15% resin, were used as reference material (designated AWC or SGC) for a detaching test. Following the packing of bone defects in the rat tibiae with either DTC or ITC, histological examination revealed that the DTC and ITC had both directly contacted the bone and were almost completely surrounded by bone by 16 weeks after the surgery and that no marked biodegradation had occurred at 52 weeks postimplantation. Rectangular plates (2 x 10 x 15 mm) of AWC, DTC, ITC, and SGC were implanted into the metaphysis of the tibia of male rabbits and the failure load was measured by a detaching test at 10 and 25 weeks after implantation. The failure loads of AWC, DTC, ITC, and SGC were 3.65, 2.21, 2.44, and 0.04 kgf at 10 weeks and 4.87, 2. 81, 2.82, and 0.13 kgf at 25 weeks, respectively. Observation of the bone-implant interface by scanning electron microscopy and energy dispersive X-ray microanalysis revealed that all the samples except SGC formed direct contact with the bone and that only AWC-implanted tibiae had a layer of a low calcium and phosphorus level at the bone-implant interface. Results showed that DTC and ITC have excellent osteoconductivity and bone-bonding ability under non-weight-bearing conditions.

Bioactive bone cement: comparison of apatite and wollastonite containing glass-ceramic, hydroxyapatite, and beta-tricalcium phosphate fillers on bone-bonding strength.

A study was conducted to compare the bone-bonding strengths of three types of bioactive bone cement, consisting of either apatite- and wollastonite-containing glass-ceramic (AW-GC) powder, hydroxyapatite (HA) powder, or beta-tricalcium phosphate (beta-TCP) powder as an inorganic filler and bisphenol-a-glycidyl methacrylate (Bis-GMA) based resin as an organic matrix. Seventy percent (w/w) filler was added to the cement. Rectangular plates (10 x 15 x 2 mm) of each cement were made and abraded with #2000 alumina powder. After soaking in simulated body fluid for 2 days, the AW cement (AWC) and HA cement (HAC) formed bonelike apatite over their entire surfaces, but the TCP cement (TCPC) did not. Plates of each type of cement were implanted into the tibial metaphyses of male Japanese white rabbits, and the failure loads were measured by a detaching test at 10 and 25 weeks after implantation. The failure loads of AWC, HAC, and TCPC were 3.95, 2.04, and 2.03 kgf at 10 weeks and 4.36, 3.45, and 3.10 kgf at 25 weeks, respectively. The failure loads of the AWC were significantly higher than those of the HAC and TCPC at 10 and 25 weeks. Histological examination by contact microradiogram and Giemsa surface staining of the bone-cement interface revealed that all the bioactive bone cements were in direct contact with bone. However, scanning electron microscopy and energy-dispersive X-ray microanalysis showed that only AWC had contacted to the bone via a Ca-P rich layer formed at the interface between the AW-GC powder and the bone, which might explain its high bone-bonding strength. Neither the HAC nor the TCPC contacted the bone through such a layer between each powder and the bone, although the HAC and TCPC directly contacted with bone. Our results indicate that all three types of abraded and prefabricated cement have bonding strength to bone, but AWC has superior bone-bonding strength compared to HAC and TCPC.

Effect of polymerization reaction inhibitor on mechanical properties and surface reactivity of bioactive bone cement.

We introduced an inhibitor to the polymerization reaction of bioactive bone cement (AWC) consisting of MgO-CaO-SiO2-P2O5-CaF2 apatite and wollastonite containing glass-ceramic powder and bisphenol-alpha-glycidyl methacrylate based resin, together with an increased amount of accelerator but without any prolongation of its setting time in order to improve the degree of polymerization and decrease the amount of incompletely polymerized monomers on the cement surface. A comparison was made between the AWC containing the inhibitor [AWC(I+)] and the AWC without it [AWC(I-)] with regard to setting parameters, mechanical properties, and surface reactivity in vitro and in vivo. The proportion of glass-ceramic powder added to the AWC was 70% (w/w). The total amount of heat generation and the peak temperature of the AWC(I+) during polymerization were slightly greater than those of the AWC(I-). The mechanical strength of AWC(I+) was higher than that of the AWC(I-) under wet conditions. In simulated body fluid, the width of the Ca-P rich layer on the surface of the AWC(I+) was less than that on the AWC(I-) after 28 days of immersion, although the rate of apatite formation on the top surface of the AWC(I+) was almost identical to that on the AWC(I-) surface. Histological examination using rat tibiae up to 26 weeks revealed that the bioactivity of the AWC(I+) was equivalent to that of the AWC(I-). Scanning electron microscopy and energy-dispersive X-ray microanalysis demonstrated that the Ca-P rich layer in the AWC(I+) was significantly narrower than that in the AWC(I-) at the same time points. These results indicate that introduction of the inhibitor improved the mechanical properties of the AWC and made the Ca-P rich layer narrower, but it had no adverse effect on bioactivity.

Bioactive bone cement: effect of the amount of glass-ceramic powder on bone-bonding strength.

We examined the influence of the proportion of glass-ceramic powder in a bioactive bone cement of our formula on the bone-bonding ability of cement. Changes in cement bonding with time also were examined. The bioactive bone cement consisted of MgO-CaO-SiO2-P2O5-CaF2 glass-ceramic powder (AW-GC powder) and bisphenol-alpha-glycidyl methacrylate (Bis-GMA)-based resin. AW-GC powder was added to the cement as 0%, 30%, 50%, 70%, and 80% w/w. Rectangular plates (2 x 10 x 15 mm) of each cement with polished surfaces were implanted into the proximal metaphysis of the tibiae of male rabbits, and the failure load was measured by detaching tests 10 and 25 weeks after implantation. The failure loads of each cement were 0% = 0.03, 30% = 1.52, 50% = 2.67, 70% = 3.56, and 80% = 5.59 kg at 10 weeks, and 0% = 0.05, 30% = 1.68, 50% = 2.77, 70% = 3.80, and 80% = 6.37 kg at 25 weeks. Observation of the cement-bone interface revealed that all bioactive bone cements (30%-80%) formed direct contact with bone whereas intervening fibrous tissue was observed in all specimens of the 0% group. By scanning electron microscopy, all bioactive bone cements (30%-80% groups) showed direct contact with bone at the cement-bone interface. In the 0% group, direct contact with bone at the cement-bone interface was not observed. By electron-probe microanalysis, a Ca-P-rich layer was not detected at the cement-bone interfaces of the 30%-70% bioactive bone cements, but in some samples of the 80% cement specimens a thin Ca-P-rich layer (3 microns thick) was observed at the interface at 10 and 25 weeks after implantation. These results show that all of the bioactive bone cements tested had the ability to bond to bone and to function as bioactive composites of ceramics and polymers.

Bioactive bone cement: comparison of AW-GC filler with hydroxyapatite and beta-TCP fillers on mechanical and biological properties.

Three types of bioactive bone cement (designated AWC, HAC, and TCPC), each consisting of bisphenol-alpha-glycidyl methacrylate (Bis-GMA)-based resin and a bioactive filler of apatite and wollastonite containing glass-ceramic (AW-GC), sintered hydroxyapatite (HA), or beta-tricalcium phosphate (beta-TCP) powder were made in order to evaluate the influence of the bioactive filler on the mechanical and biological properties of bone cement. The proportion of filler added to the cements was 70% w/w. The compressive, bending, and tensile strengths and the fracture toughness of AWC were higher than HAC and TCPC under wet conditions. The cements were evaluated in vivo by packing them into the intramedullary canals of rat tibiae. An affinity index that equalled the length of bone in direct apposition to the cement was calculated for each cement and expressed as a percentage of the total length of the cement surface. Histological examination of rat tibiae up to 8 weeks after implantation revealed that AWC had higher bioactivity than HAC and TCPC. New bone had formed along the AWC surface within 2 weeks, and at 4 weeks newly formed bone surrounded the cement surface almost completely. In HAC- and TCPC-implanted tibiae, immature bone had formed directly toward but not along the cement surface at 2 weeks. Observation of cement-bone interfaces showed that AWC had bonded to the bone via a so-called "Ca-P-rich layer"; the cement-bone interface remained stable, and the width of the CA-P-rich layer became thicker with time. On the other hand, in HAC- and TCPC-implanted tibiae, the cement surface fillers were surrounded by new bone and were absorbed gradually to become bone matrix. The cement-bone interfaces went inside the cement with time. Our results indicate that stronger interstitial bonding between the inorganic filler and the organic matrix resin in AWC lead to higher mechanical properties; results also indicate that the more stable cement-bone interface and higher bioactivity of AWC are due to early and uniform apatite formation on the cement surface.

Mechanical and biological properties of bioactive bone cement containing silica glass powder.

Silica glass powder (SG-P) made by a fusing-quenching method was added as a second filler to a bioactive bone cement consisting of MgO-CaO-SiO2-P2O5-CaF2 apatite and wollastonite containing glass-ceramic powder (AW-P) and bisphenol-a-glycidyl methacrylate (Bis-GMA)-based resin, to achieve a higher mechanical strength and better handling properties in use. Five types of cement were used, containing different weight ratios of AW-P/SG-P (Group 1 = 100/0; Group 2 = 75/25; Group 3 = 50/50; Group 4 = 25/75; and Group 5 = 0/100) as filler, to evaluate the effect of SG-P content on the biological, mechanical, and handling properties. The total proportion of filler added to the cements was 85% w/w. The compressive, bending, and tensile strengths and fracture toughness of the cements increased with SG-P content. The viscosity of cements also increased with SG-P content, and every cement could be handled manually. The cements were evaluated in vivo by packing the intramedullary canals of rat tibiae. An affinity index was calculated for each cement; this was the length of bone directly apposed to cement expressed as a percentage of the total length of the cement surface. Histological examination of implanted tibiae for up to 26 weeks showed that the affinity indices decreased with SG-P content and that those of all the cement groups increased with time. At 26 weeks, Groups 1 and 2 had almost identical affnity indices (79% and 75%; no significant difference) but those of the other groups remained at <50%. Group 2 had better mechanical and handling properties than Group 1, and an SG-P content in the filler of no more than 25% w/w did not interfere strongly with the bioactivity of the cement.

Direct bone formation on alumina bead composite.

We have developed a composite (designated ABC), consisting of alumina bead powder as an inorganic filler and bisphenol-alpha-glycidyl methacrylate (Bis-GMA)-based resin as an organic matrix, which allows direct bone formation on its surface in vivo. Alumina bead powder was manufactured by fusing crushed alpha-alumina powder and quenching it. The beads took spherical form 3 microns in average size. According to powder X-ray diffraction and Fourier transform infrared spectroscopy, the alumina bead powder was composed of amorphous and delta-crystal phases of alumina in its main crystal structure. Fused-quenched silica glass-filled composite (SGC) was used as a control. The proportion of filler added to the composites was 70% w/w. Mechanical testing of the ABC indicated that it would be strong enough for use under weight-bearing conditions. No apatite formation was detected on the surfaces of either composite after soaking in simulated body fluid for 28 days in vitro. Histological examination of rat tibiae for up to 8 weeks revealed that ABC bonded to bone directly via a layer of calcium, phosphorus, and alumina with no interposed soft-tissue layer. Moreover, the amount of bone directly apposed to the ABC surface increased with time, whereas with SGC there was poor direct bone formation even at 8 weeks. The precise mechanism of direct bone formation on ABC is as yet unknown but it is possible that changes in the crystallinity of alumina, which is known to be highly biocompatible, contribute to its excellent osteoconductivity in vivo. Although bioactive materials such as Bioglass or apatite and wollastonite-containing glass-ceramic have previously been reported to form bone-like apatite on their surfaces under acellular conditions via simple chemical reactions, ABC does not have such characteristics, and presenting favorable conditions for osteoconduction and tissue calcification may lead to direct bone formation on its surface in vivo.

Histamine activates bronchial epithelial cells to release inflammatory cytokines in vitro.

Airway epithelial cells have a potential to produce cytokines which are relevant to airway inflammation. To elucidate the mechanisms of their regulation, we focused on the effects of three chemical mediators [histamine, platelet-activating factor (PAF) and endothelin-1] important in the pathogenesis of bronchial asthma. Histamine, but not PAF or endothelin-1, showed a dose-dependent stimulatory effect on the release of interleukin-6, interleukin-8 and granulocyte-macrophage colony-stimulating factor by normal and transformed human bronchial epithelial cells when studied 6 h after the treatment. The process required protein synthesis as evaluated by the effect of cycloheximide, and was mainly via H1 receptor. We concluded that histamine might be involved in the activation of airway epithelial cells to release inflammatory cytokines in allergic responses.

Erythromycin suppresses interleukin 6 expression by human bronchial epithelial cells: a potential mechanism of its anti-inflammatory action.

We evaluated the effects of several antibiotics on IL-6 expression by human bronchial epithelial cells, potent sources of this proinflammatory cytokine important in airway inflammation. Among those tested, erythromycin (EM) and clarithromycin (CAM) uniquely suppressed mRNA levels as well as the release of IL-6 at the therapeutic and non-cytotoxic concentration (10(-6)M). Our findings suggested that these macrolide antibiotics had suppressive effect on cytokine expression in human cells, and this new mode of action may have relevance to their clinical effectiveness in airway inflammatory diseases.

Combined effects of diltiazem and oxygen in pulmonary hypertension of mixed connective tissue disease.

A 45-year-old woman with pulmonary hypertension and mixed connective tissue disease (MCTD) underwent right heart catheterization to evaluate the effects of vasodilators. Nasal oxygen at 2 l/min in addition to 300 mg diltiazem improved pulmonary hemodynamics without adverse effects. After 1 year of diltiazem and home oxygen, sustained favorable hemodynamic effects were obtained, which were more marked than the acute effects. We conclude that this combination may be a potent treatment for pulmonary hypertension in patients with MCTD.