Plasma spraying of zirconia-reinforced hydroxyapatite composite coatings on titanium: part I: phase, microstructure and bonding strength

Plasma-sprayed hydroxyapatite (HA) coatings applied to metal substrates can induce a direct chemical bond with bone and hence achieve biological fixation of the implant. However, the poor bonding strength between HA and substrate has been of concern to orthopaedists. In this study, two submicrometre ZrO2 powders stabilized with both 3 and 8 mol% Y2O3 (TZ3Y and TZ8Y, respectively) were incorporated in a plasma-sprayed HA coating on Ti-6Al-4V substrate to investigate the change in phase, microstructure and bonding strength. The results show that ZrO2 composite coatings contain more unmelted particles and greater porosity. During plasma spraying, ZrO2 reacts with the CaO in HA to form CaZrO3 and accelerates HA decomposition to alpha-TCP and Ca4P2O9. Nevertheless, bonding strength increases with increase of ZrO2 content in the range 0 to 10 wt% studied. The higher Y2O3-containing TZ8Y apparently exerts a greater strengthening effect than the lower Y2O3-containing TZ3Y.

[Three dimensional FEM analysis of stress distribution around dental implants to estimate the influence of the length]

The effect of the length of implants on stress distribution is one of the important subjects in implantology.In this study,Three dimensional finite element methods model was constructed by dental CT images,The purpose of this study was to evaluate the stress distribution in bone adjacent to an implant after application of loading in horizontal,oblique and vertical direction.It was show that the highest stress occured at the cervical bone margin adjacent to the implant only 10% decrease in inverse two times increase in implant length,and correlated little to the implant length,therefore,it was unnecessary to emphasize the length of the implants in clinic.

Magnesium and calcium in drinking water and cerebrovascular mortality in Taiwan

The relationship between death from cerebrovascular disease and the levels of magnesium and calcium in drinking water was examined using an ecological design. The study area consisted of 227 municipalities in Taiwan. Data on the levels of magnesium and calcium in drinking water have been collected from the Taiwan Water Supply Corporation (TWSC). These levels of magnesium and calcium were compared using the standardized mortality ratios (SMRs) for cerebrovascular disease (1981-1990). A statistically significant inverse relationship was present between cerebrovascular mortality and levels of both magnesium and calcium after adjusting for urbanization index. After adjustment for calcium levels in drinking water and urbanization index, the weighted multivariate-adjusted regression coefficient indicated a decrease of 0.248 in the standardized mortality ratios (SMRs) for every 100 mg/L increase in magnesium levels in drinking water. The results from this study strengthen the hypothesis that magnesium in drinking water helps to prevent death from cerebrovascular disease.

Long-term vegetarian diet and bone mineral density in postmenopausal Taiwanese women

This study examined bone density among postmenopausal Buddhist nuns and female religious followers of Buddhism in southern Taiwan and related the measurements to subjects characteristics including age, body mass, physical activity, nutrient intake, and vegetarian practice. A total of 258 postmenopausal Taiwanese vegetarian women participated in the study. Lumbar spine and femoral neck bone mineral density (BMD) were measured using dual-photon absorptimetry. BMD measurements were analyzed first as quantitative outcomes in multiple regression analyses and next as indicators of osteopenia status in logistic regression analyses. Among the independent variables examined, age inversely and body mass index positively correlated with both the spine and femoral neck BMD measurements. They were also significant predictors of the osteopenia status. Energy intake from protein was a significant correlate of lumbar spine BMD only. Other nutrients, including calcium and energy intake from nonprotein sources, did not correlate significantly with the two bone density parameters. Long-term practitioners of vegan vegetarian were found to be at a higher risk of exceeding lumbar spine fracture threshold (adjusted odds ratio = 2.48, 95% confidence interval = 1.03-5.96) and of being classified as having osteopenia of the femoral neck (3.94, 1.21-12.82). Identification of effective nutrition supplements may be necessary to improve BMD levels and to reduce the risk of osteoporosis among long-term female vegetarians.

[Stress research on support tissues of Buffer-typed conical telescopic removable denture]

In order to explore the biomechanical physiology of Buffer-typed conical telescopic removable denture restoring defected dentition with a preponderance of teeth lost and only a few remained,the authors have studied the stress distribution of the periodontal support tissue of abutments and subbasal support tissue when subjected to forced transfered from removable denture of both Buffer-typed and non Buffer-typed telescopic retainers.The results suggest that occlusal forces can be redistribute through dentures with buffer typed conical telescopic retainers which decrease forces sustained by abutments and increase the ones by subbasal support tissues thus avoiding trauma of abutments while having certain degree if physiological stimuli.We can also decrease the forces transfered to subbasal support tissues by expanding basal areas,so to alleviate the absorption of alveolar ridges.This resut is in accordance with clinical effects.

Cancer mortality and residence near petrochemical industries in Taiwan

An ecologic study design was used to investigate the relationship between cancer risks and residence in communities adjacent to petrochemical industrial counties (PICs). Directly age-adjusted mortality rates for cancer during 1982-1991 among 16 counties characterized by a heavy concentration of petrochemical industries were compared to rates among 16 matched counties with similar concentration of nonpetrochemical manufacturing industries, urbanization level, and demographic characteristics. An excess rate for liver cancer among males was found in the so-called PICs. The correlation could not be explained by confounding variables such as urbanization, socioeconomic class, or employment in nonpetrochemical industries. No other increased cancer risks were found to be associated with residence near petrochemical industries.

Oxidative modifications of apoB-100 by exposure of low density lipoproteins to HOCL in vitro

Although the products of oxidation of the lipid components of LDL have been studied extensively, much less is known about the specific products of oxidative modification of the apoprotein. We reacted native LDL and LDL that had been treated with HOCl with 2,4-dinitrophenylhydrazine (DNPH), delipidated and trypsinized the protein, and analyzed the products by HPLC. Although tryptic digests of native LDL and LDL oxidized by limited quantities of HOCl showed similar patterns by HPLC with detection at 220 nm, oxidized LDL showed several discrete peaks at 365 nm, which is characteristic of hydrazones formed with aldehydes and ketones, commonly termed protein carbonyls. Native LDl showed no peaks in the chromatograms at 365 nm. Peptides absorbing at 365 nm were isolated by HPLC and characterized. In most cases, the probable sites of modification on the peptides could be implied by failure of an anticipated amino acid to appear in the expected sequence. Of the 14 peptides isolated and characterized to date, eight peptides contained Cys residues. In other peptides, Lys, Trp, and Met were identified as amino acid residues apparently modified by HOCl treatment of LDL. Thirteen of the peptides identified are from trypsin-releasable peptides located on the surface of unoxidized native LDL. Our studies suggest a selective process of modification of apoB-100 by HOCl and the approaches used in the present studies should be useful for the characterization of the mechanisms of oxidation of this and other proteins.

Respiratory and irritant health effects of a population living in a petrochemical-polluted area in Taiwan

Reported herewith are the results from an ongoing study of outdoor air pollution and the health of persons living in the communities in close proximity to petrochemical industrial complexes. To determine if there is an excess of adverse health outcomes in the population exposed to petrochemical industrial emissions, a health survey was undertaken in 1996 in this area and in one reference area which has no local industrial emissions. The subjects were 436 adults (30-64 years of age) living in the Sanwei area (exposed area) and 488 in Taicei (reference area). For several indicators of respiratory health, including cough, wheezing, and chronic bronchitis, the prevalence rates were not significantly different between the study and the control populations. Acute irritative symptoms (eye irritation, nausea, throat irritation, and chemical odor perception) were significantly more common in the exposed area, particularly perception of chemical odors (84.6% vs 2.1%). It is concluded that exposure to petrochemical air emissions may be associated with increased rates of acute irritative symptoms. Future studies are needed to identify the potential role of petrochemical industrial emissions (particularly volatile organic compounds) in the genesis of acute irritative symptoms in a nearby petrochemical industrial area.

Oxidation of bovine beta-casein by hypochlorite

We recently observed two 2,4-dinitrophenylhydrazine (DNPH)-reactive proteins of 40 and 120 kDa in the bronchoalveolar lavage fluids of rats exposed to >95% O(2) for 48 h. The N-terminal sequences of these proteins were both identical over 16 amino acids with rat beta-casein, which, in addition to its more common association with milk, is produced by cytotoxic T-lymphocytes, and has been found to have proinflammatory properties. Because of the inflammatory response that accompanies hyperoxic lung injury, we investigated the oxidation of bovine beta-casein by HOCl. Following exposure to HOCl at 4 degrees C for 15 min, derivatization with DNPH, washing, and digestion with trypsin, the resultant peptides were separated by reverse-phase HPLC. One peptide isolated from a peak absorbing at 365 nm was identified as AVP(Y*)PQR, corresponding to amino acids 177-183 of bovine beta-casein. Analysis of the peptide by both electrospray and matrix assisted laser desorption ionization (MALDI) mass spectrometry identified a molecular ion MH+ of 1008.5 Da, which represents an increase of 178 Da from the calculated monoisotopic MH+ of the unmodified peptide of 830.45 Da. Daughter ion spectra of the doubly charged parent ion of the peptide further support the oxidation of the tyrosine to the quinone methide, with subsequent conversion to the corresponding hydrazone with DNPH. A second pair of products were identified as arising from oxidation of Y(193) within the tryptic peptide constituted by amino acids 184-202, and the corresponding chymotryptic cleavage side product, 191-202. Exposure of beta-casein to increasing amounts of HOCl revealed that M and Y residues were the most susceptible, although bovine beta-casein contains no C, and a single W, which would not be detected by our methods. The approach described in the present report can be used to evaluate the contributions of distinct mechanisms of oxidation in other experimental or pathological models.

Effects of occupational dust exposure on the respiratory health of Portland cement workers

The object of this study was to assess the relationship between occupational Portland cement dust exposure and respiratory health. Respiratory symptoms and ventilatory function were studied in a group of 591 male Portland cement workers employed in four cement plants. The prevalence of chronic respiratory symptoms was higher in exposed than in control workers. The exposed group had a significantly lower mean forced vital capacity (FVC), forced expiratory volume at 1 s (FEV1), and forced expiratory flows after exhalation of 50% and 75% of the vital capacity (FEF50, FEF75) than the control group. The data suggest that occupational exposure to Portland cement dust may lead to higher prevalence of chronic respiratory symptoms and the reduction of ventilatory capacity.

First direct evidence for lipid/protein conjugation in oxidized human low density lipoprotein

It has been postulated that lipids incorporated in atherosclerotic plaques are derived from the uptake of oxidized low density lipoprotein (LDL) by a macrophage-bound receptor. In vitro studies of LDL oxidation have established that reactive lipids are formed and that the exposure of native LDL to these products leads to modified protein with physical properties similar to oxidized LDL. Here we describe the application of highly specific tandem mass spectrometric techniques to the first characterization of lipid-modified LDL by demonstrating the addition of 4-hydroxy-2-nonenal to histidine residues of apolipoprotein B-100, following oxidation of LDL. The modified residues have been assigned to specific locations that have been previously shown to reside on the surface of the LDL particle.

Effects of gemfibrozil on very-low-density lipoprotein composition and low-density lipoprotein size in patients with hypertriglyceridemia or combined hyperlipidemia

To examine the effects of gemfibrozil on very-low-density lipoprotein (VLDL) composition and low-density lipoprotein (LDL) size, five men with hypertriglyceridemia (HTG) alone and five men with HTG and hypercholesterolemia (combined hyperlipidemia, CHLP) were randomized for 8 weeks to Lopid SR (slow-release gemfibrozil; two 600-mg tablets once per day) or placebo in a crossover study. Drug therapy versus placebo significantly decreased plasma triglyceride (68%), and VLDL (77%), and significantly increased high-density lipoprotein cholesterol (25%); total cholesterol, apolipoprotein B and lipoprotein[a] concentrations did not change significantly. With drug, mean total apoE in plasma was 53% lower in patients with HTG and 39% lower in patients with CHLP. Gemfibrozil significantly affected VLDL composition: protein increased 26%, molar ratio of apoE to apoB reduced 48%, apoC-II increased 19%, and apoC-III decreased 9%. LDL cholesteryl ester significantly increased with drug treatment. VLDL subfractions were separated and classified as heparin binding (VLDLR, apoE rich) or nonbinding (VLDLNR-1 and VLDLNR-2, both apoE poor). All VLDL subfractions were significantly lower with drug therapy, and the differences for total VLDL and for VLDL subfractions were greater in patients with HTG. With placebo, VLDLR accounted for 41.8% of VLDL in HTG and 49.0% of VLDL in CHLP, reduced to 27.6% and 38.6%, respectively, with gemfibrozil. Taken together, these results suggest that treatment with gemfibrozil reduces plasma concentrations of VLDL and alters the apoprotein composition of VLDL in a manner that may favor LDL- and VLDL-receptor-mediated clearance of the apoE-rich VLDL subfraction, thereby reducing TG-rich particle concentrations, and possibly reducing risk for coronary heart disease.

Erratic passage and anchorage of a right subclavian catheter caused by preoccupancy of an indwelling right jugular venous catheter--a case report

We report a case of central venous catheter (CVC) malposition. Through subclavian approach the CVC tip was intended to anchor in the superior cava, but it turned out to be in the right internal jugular vein as revealed by chest X-ray. The cause of malposition was perhaps the preoccupancy of the jugular venous CVC which interferred with a normal advancement. Although the malposition of the catheter might not produce any immediate problem, later complication might occur. Thus, removal of a problematic catheter and recatheterization was indicated.

Relationship between water hardness and coronary mortality in Taiwan

A number of studies carried out in other countries have shown the existence of negative correlations between coronary mortality and the hardness of water supplies. Data on water hardness throughout Taiwan have been collected from Taiwan Water Supply Corporation (TWSC) to examine the ecological correlation between deaths from coronary disease (1981-1990) and total hardness in drinking water. Analysis demonstrates a significant negative association between drinking water hardness and coronary mortality. After adjustment for the urbanization index, coronary mortality in municipalities with soft water was estimated to be 9.6% higher than that in municipalities with hard water. The weighted multivariate-adjusted regression coefficient indicated a decrease of 0.053 in standardized mortality ratios (SMRs) for every 100 mg/L increase in total hardness in drinking water after allowing for the urbanization condition.

Two-stage cementless revision THR after infection. 5 recurrences in 40 cases followed 2.5-7 years

We revised 40 infected hip prostheses in 40 patients as a two-stage procedure, including intravenous and oral antibiotics, gentamicin beads, and delayed cementless implantation of porous-coated THR. The duration of antibiotic treatment was 8 weeks. The interval from resection to reimplantation was, on average, 48 (8-108) weeks. 39 patients were followed, on average, 4 (2.5-7) years. 5 patients had a recurrent infection. In patients who did not have a recurrent infection, the Harris hip score exceeded 80 in 32 patients. Radiographically, femoral component migration of 2-6 mm was noted in 3 cases. The recurrent infection rate, and the functional and radiographic results are comparable with those obtained using a two-stage procedure with antibiotic cement.

Glutamate immunoreactivity in the tiger salamander retina differentiates between GABA-immunoreactive and glycine-immunoreactive amacrine cells

A higher proportion of retinal amacrine cells, largely thought to be inhibitory, in tiger salamander retina are immunoreactive (+) for the excitatory amino acid glutamate than for either of the inhibitory amino acids, GABA and glycine. The colocalizations of glutamate immunoreactivity, GABA immunoreactivity and glycine immunoreactivity were studied in the proximal retina of tiger salamander using postembedding immunocytochemical methods in consecutive semithin sections. A considerable degree of colocalization was observed between glutamate immunoreactivity and GABA immunoreactivity and to a lesser extent with glycine immunoreactivity. No glutamate-immunoreactive cells were single labelled in INL3 (proximal inner nuclear), 12% were single labelled in INL2 (mid INL; these are bipolar cells), 62% were singled labelled in the ganglion cell layer (GCL) and likely to be ganglion cells. Single-labelled glycine-immunoreactive cells comprised 16% in INL3, 2%; INL2 and GCL, 0%). Glutamate immunoreactivity co-localized four times as often with GABA immunoreactivity than glycine immunoreactivity in INL3 (77% versus 19%), comparably in INL2 (37% and 32%) and six times as often in the GCL (29% versus 5%). A computerized image analysis of the relative intensities of glutamate immunoreactivity in GABA-immunoreactive/glutamate-immunoreactive and glycine-immunoreactive/glutamate-immunoreactive double labelled amacrine cells in INL3 revealed that all glycine-immunoreactive cells contained low intensities of glutamate immunoreactivity; whereas 35% of GABA-positive cells had medium to high intensities of glutamate immunoreactivity. There was a significant correlation (r = 0.44; p < 0.01) between the intensities of glutamate immunoreactivity and GABA immunoreactivity in GABA-immunoreactive/glutamate-immunoreactive amacrine cells. The common colocalization of glutamate immunoreactivity with GABA immunoreactivity and the positive correlation of their relative intensities suggests that glutamate is likely to serve as a precursor for GABA synthesis. However, intense glutamate immunoreactivity in 5% of the amacrine cells suggests a transmitter function. Glycine-immunoreactive amacrine cells contained little or no glutamate immunoreactivity, suggesting a minimal role for glutamate as a neurotransmitter in these cells. The major distribution of intense glutamate immunoreactivity is in bipolar cells and ganglion cells, consistent with data suggesting that glutamate is the transmitter in the retinal through pathway.

Cementless reimplantation of hydroxyapatite-coated total hips after periprosthetic infections

From February 1991 to July 1993, 26 hydroxyapatite (HA) coated total hips were implanted in 26 patients with infected hip prostheses. Seven were done as one-stage exchange arthroplasties and the other 19 were delayed reimplantations. Successful reimplantation was defined as a functioning hip without recurrence of infection at least 2 years after reimplantation. During a follow-up period of 25 to 54 months, 24 of the reimplantations were successful. Our success rate using the HA-coated prosthesis is similar to previous reports that used antibiotic impregnated bone cement. The HA method avoids the complications encountered with bone cement.

Subunit structure of vacuolar proton-pyrophosphatase as determined by radiation inactivation

Vacuolar proton-pyrophosphatase (H(+)-PPase) of mung bean seedlings contains a single kind of polypeptide with a molecular mass of approx. 73 kDa. However, in this study, a molecular mass of approx. 140 kDa was obtained for the purified vacuolar H(+)-PPase by size-exclusion gel-filtration chromatography, suggesting that the solubilized form of this enzyme is a dimer. Radiation inactivation analysis of tonoplast vesicles yielded functional masses of 141.5 +/- 10.8 and 158.4 +/- 19.5 kDa for PP1 hydrolysis activity and its supported proton translocation respectively. These results confirmed the in situ dimeric structure of the membrane-bound H(+)-PPase of plant vacuoles. Further target-size analysis showed that the functional unit of purified vacuolar H(+)-PPase was 71.1 +/- 6.7 kDa, indicating that only one subunit of the purified dimeric complex would sufficiently display its enzymic reaction. Moreover, in the presence of valinomycin and KCl, the functional size of membrane-bound H(+)-PPase was decreased to approx. 63.4 +/- 6.3 kDa. A working model was proposed to elucidate the structure of native H(+)-PPase on vacuolar membrane as a functional dimer. Factors that would disturb the membrane, e.g. membrane solubilization and the addition of valinomycin and KCl, may induce an alteration in its enzyme structure, subsequently resulting in a different functional size.

Intrathecal ketamine reduces morphine requirements in patients with terminal cancer pain

PURPOSE

Ketamine has been administered epidurally and intrathecally for operative and post-operative pain control. Animal studies showed potentiation of analgesia induced by ketamine and morphine. We hypothesized that intrathecal ketamine would potentiate the effects of intrathecal morphine in the treatment of cancer pain.

METHODS

A double blind, cross over study was designed to evaluate the effect of ketamine on spinal morphine analgesia in terminal cancer pain patients. A two-phase protocol was used; phase M, intrathecal morphine alone twice daily; phase M + K, co-administration of ketamine (1.0 mg) with morphine intrathecally twice daily. The dose of morphine was titrated upwards until acceptable pain relief was achieved, defined by numeric rating scales (0-10) < or = 3, and the rescue dose of morphine was less than 5 mg after each intrathecal administration for two days. The dose of intrathecal morphine was defined as the effective dose.

RESULTS

The effective dose of intrathecal morphine in phase M of 0.38 +/- 0.04 mg.day-1 was higher than that in phase M + K (0.17 +/- 0.02 mg.day-1) (P < 0.05). The average pain scales were 7.95 +/- 0.25 before intrathecal drug administration. Pain scales were decreased to 2.2 +/- 0.17 (P < 0.05) in phase M and 1.95 +/- 0.20 (P < 0.05) in phase M + K after the effective dose of morphine had been reached. No serious side effects were observed in this study.

CONCLUSION

The present study demonstrates that ketamine enhances the analgesic effect of morphine, thus reducing the dose of intrathecal morphine.

Propofol inhibits cardiac L-type calcium current in guinea pig ventricular myocytes

BACKGROUND

Propofol may exert negative inotropic and chronotropic actions in the heart. Single-channel studies show that propofol affects the kinetics of opening and closing of cardiac L-type calcium channels (ICa(L)) without altering channel conductance. The aim of this study was to investigate the mechanisms of depressant effects of propofol on cardiac whole-cell ICa(L).

METHODS

Single ventricular myocytes were freshly dissciated from guinea pig hearts using enzymatic isolation. One-suction electrode voltage-clamp technique (whole-cell mode) was used. LCa(L) was separated from other contaminated ionic currents. Propofol was applied in the commercial 10% Intralipid emulsion formula (Zeneca, UK).

RESULTS

In isolated cardiomyocytes, propofol significantly inhibited whole-cell ICa(L) in a concentration-dependent manner (K D = 52.0 microM; Hill coefficient = 1.3). The solvent (Intralipid) did not affect ICa(L). Propofol decreased ICa(L) at all potentials tested along the voltage axis and reduced the slope conductance. The threshold potential for activation and the peak potential of the current-voltage relationship were not changed by propofol. The steady-state activation curves overlapped in the absence and the presence of 56 microM propofol. In contrast, the steady-state inactivation curve was shifted in the hyperpolarizing direction. The time course of the recovery from inactivation was delayed by 56 microM propofol. The blocking action on ICa(L) of propofol shows marked resting block and use-dependent block. Propofol caused more pronounced inhibition at a higher stimulation frequency. The effect of propofol on the inactivation process was even more clear on ICa(L).

CONCLUSIONS

The authors conclude tha propofol, at supratherapeutic concentrations, inhibits cardiac ICa(L). This inhibition is mainly due to a shift of inactivation curve and a reduction in slope conductance.

Late-onset idiopathic hypoparathyroidism with thymoma: a case report

A 62-year-old male was admitted because of numbness and twitching of both hands. Hypocalcemia with positive Trousseau's sign was noted. Chest X-ray and computed tomography (CT) showed an anterior mediastinal mass. Skull X-ray and whole body bone scan could not rule out bony metastasis to the left parietal bone, causing an anterior mediastinal tumor with bony metastasis to be suspected initially. Median sternotomy and extended thymectomy were done, and Stage II thymoma with negative calcitonin staining was noted. However, hypocalcemia persisted after thymectomy and the results of pre-operative and post-operative intact-parathyroid hormone (intact-PTH) were less than the detection limit (<13.3 pg/ml). Tumor markers and gallium tumor scan were all negative. Brain CT disclosed calcification over the bilateral basal ganglia and bilateral dentate nuclei of the cerebellum; the supposed metastatic osteolytic lesions of parietal bone were considered to result from pacchionion arachnoid granulation tissues. The coexistence of late-onset idiopathic hypoparathyroidism and thymoma has not been reported before. Long-term replacement therapy with vitamin D and calcium was necessary for this case.

In hypercholesterolemia, lower peripheral monocyte count is unique among the major predictors of atherosclerosis

Many studies have shown that enhanced monocyte adherence is an important factor in the initiation of atherosclerosis. Because the relationships between circulating monocyte count and atherosclerosis or its major predictors have received little attention, we conducted this study with the aim of clarifying these relationships. The study included 409 men and women who underwent a carotid artery duplex study and white blood cell analysis (Sysmex Cell Counter) during a 2-day health check at our hospital in 1994. We found no correlation between preexisting carotid atherosclerosis and monocyte count. After adjustment for age and sex, hypercholesterolemia, among the major predictors of atherosclerosis, showed a unique correlation with both lower monocyte count and percentage (P < .001, P < .0001, respectively), whereas smoking was correlated with a higher monocyte count (P < .001). There was a slight but nonsignificant increase in monocyte count in hypertension, diabetes, and hypertriglyceridemia. Our results imply that: (1) hypercholesterolemia has a strong, peripheral monocyte-reducing effect, probably due to direct enhancement of monocyte adhesion to the endothelium, which subsequently initiates the atherosclerotic process, and (2) the mechanisms of other predictor(s)-induced atherosclerosis may be quite different from that of hypercholesterolemia. Another possible explanation for the inverse correlation between monocyte count and serum cholesterol level is that decreased monocyte levels might lead to hypercholesterolemia because of decreased uptake of cholesterol from the plasma by less monocyte-derived macrophages. The reasons why preexisting carotid atherosclerosis did not correlate with monocyte count are also discussed.

Interaction of apolipoprotein[a] with apolipoproteinB-100 Cys3734 region in lipoprotein[a] is confirmed immunochemically

Monospecific polyclonal antibodies (MPAbs) to apoB-100 regions Cys3734 and Cys4190 were isolated by affinity chromatography using the synthetic polypeptides, Q3730VPSSKLDFREIQIYKK3746 and G4182IYTREELSTMFIREVG4198, respectively, coupled to a hydrophilic resin. Molecular modeling and fluroescence labeling studies have suggested that Cys67 located in kringle type 9 (LPaK9, located between residues 3991 and 4068 of the apo[a] sequence inferred by cDNA) of the apo[a] molecule is disulfide linked to Cys3734 of apoB-100 in human lipoprotein[a] (Lp[a]). This possibility has been further explored with MPAbs. Four species of MPAbs directed to a Cys3734 region of apoB-100 (3730-3746) were isolated from goat anti-human LDL serum by a combination of synthetic peptide (Q3730VPSSKLDFREIQIYKK3746) affinity chromatography and preparative electrophoresis (electrochromatography). MPAbs to the Cys4190 region of apoB-100, a second or alternative disulfide link-site between apo[a] and apoB-100, were also isolated using a synthetic peptide (G4182IYTREELSTMFIREVG4198) affinity resin. Results of immunoassays showed that binding of these four MPAbs to Lp[a] was significantly lower than to LDL. In contrast, MPAbs to the apoB-100 region 4182-4198 which contains Cys4190, a second or alternative disulfide link-site between apo[a] and apoB-100, displayed a less significant difference in binding to Lp[a] and LDL. These results provide additional evidence that the residues 3730-3746 of apoB-100 interact significantly with apo-a- in Lp-a-, and that Cys3734 is a likely site for the disulfide bond connecting apo[a] and apoB-100.

Upright postures and isoproterenol infusion for provocation of neurocardiogenic syncope: a comparison of standing and head-up tilting

Head-up tilt testing has proved to be useful in provocation of neurocardiogenic syncope. The purpose of this study was to examine whether simply assuming an upright posture by standing can be an alternative to the head-up tilt testing for diagnosis of neurocardiogenic syncope. Eighty-four patients with recurrent unexplained syncope and 22 normal volunteers were recruited into the study. Forty-seven patients with syncope and all normal volunteers received the standing test. Thirty-seven of the patients with syncope received head-up tilt testing (90 degrees). All subjects lay down for 5 minutes and then assumed an upright posture until syncope or presyncope occurred or until a maximum of 10 minutes was reached in each stage of the test. The tests included four stages: baseline and infusion of 1, 2, or 3 micrograms/min isoproterenol in each of the successive stages. Five subjects could not tolerate the procedure, and further testing was terminated. Overall, the standing test was positive in 83% of the patients with syncope, and its specificity was 74%. The head-up tilt testing was positive in 75% of the patients with syncope. The duration of assuming an upright posture before occurrence of syncope or presyncope was significantly longer in the syncope-tilting group in the third stage (p < 0.01) and the fourth stage (p < 0.05) compared with the syncope-standing group. However, the curves of the time course for cumulative positive rates were not significantly different (p = 0.0739) in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in phases and crystallinity of plasma-sprayed hydroxyapatite coatings under heat treatment: a quantitative study

With three kinds of plasma-sprayed hydroxyapatite coatings (HACs) prepared, the objectives of this study were (1) to establish the calibration methods for quantitatively measuring the concentration of impurity phases and the degree of crystallinity of the HACs, and (2) to explore the effects of postheat treatments at various temperatures in vacuo on the changes of phases and crystallinity of the HACs. By the internal standard method used, the concentrations of impurity phases, such as alpha-TCP, beta-TCP, and TP, of the assprayed HACs were significantly higher than those measured by the direct intensity-ratio method, and the CaO phase was lower than the direct intensity-ratio method. When the HACs were heat treated in the temperature interval 630-850 degrees C, the concentrations of impurity phases obviously decreased, and the coating crystallinity apparently increased. After annealing at 850 degrees C, an HAC consisting of at least 95% crystallinity with few impurity phases was obtained. As the annealing temperatures in the interval 850-1000 degrees C were applied, however, the HA phase seriously decomposed, resulting in the appearance of a large number (higher than 20 wt%) of impurity phases in the HACs. This work suggests that the optimum heat treatment conditions in vacuo for maximizing crystallinity and minimizing impurity phases of the HACs do not occur at the same temperature.

[Static palatography and image processing system by computer.]

In this study the artificial palates made of black vinyl seat covering the palate and occlusal surfaces of maxillary teeth were coated with white alginate powder and inserted into the mouth of the subjects.After pronunciation of the test sounds,the tongue contact areas on artificial palate were demonstrated by wetting of powder and changing in color from white to black.Thus,photographnys of palatograms were taken.After taking 5 palatogram of each sound,the samples were averaged by an image processor.The averaged outline of each subject's palatogram was converted into a standarized dental arch form,with the gray scale of each image reversed and reduced,and then added to every pattern of the same sound produced by all subjects.Thus,palatograms were based on the frequency of over lapping.From this compiling, contact areas that were common in more than four out of six subjects were extracted.

Electropharmacological actions of propofol on calcium current in guinea-pig ventricular myocytes

Propofol, a widely-used intravenous anesthetic, causes bradycardia, depression in contractility and hypotension. The cellular mechanisms responsible for these cardiac toxicity remain unclear. In this study, we examined the cellular electropharmacological actions of propofol on calcium current in guinea-pig heart. Single ventricular myocytes were freshly isolated from guinea-pig using modified enzymatic method. Whole-cell voltage-clamp technique was applied with one suction pipette. Transmembrane L-type calcium current (ICa(L)) was separated from other ionic currents by voltage-control, ionic channel blockers and ion substitution methods. Our results show that propofol decreased ICa(L) in a concentration-dependent manner (KD = 54.2 microM). Slope conductance of current-voltage relation was decreased by 56 microM propofol. Propofol did not affect the steady-state activation curve, but shifted the inactivation curve to hyperpolarizing direction. Recovery from inactivation was slowed down by propofol. Marked resting block and use-dependent block were noted. In conclusion, our results indicate that propofol inhibits cardiac L-type calcium current mainly by shifting inactivation curve and retarding the recovery from inactivation.

ELISA quantitation of apolipoproteins in plasma lipoprotein fractions: ApoE in ApoB-containing lipoproteins (Lp B:E) and ApoB in ApoE-containing lipoproteins (Lp E:B)

Growing clinical evidence suggests that metabolic behavior and atherogenic potential vary within lipoprotein subclasses that can be defined by apolipoprotein variation. Variant constituency of apolipoproteins B and E (apoB and apoE) may be particularly important because of the central roles of these apolipoproteins in the endogenous lipid delivery cascade. ApoB is the sole protein of low-density lipoprotein (LDL), and like LDL cholesterol, the plasma apoB level has been positively correlated with risk for atherosclerotic disease. ApoE is a major functional lipoprotein in the triglyceride-rich lipoproteins, and may be crucial in the conversion of very low density lipoprotein (VLDL) to LDL. Based on work by others that enabled the quantititation of apoB-containing particles by content of up to two other types of apolipoprotein, we have developed a method for determining the amount of apoE in apoB-containing lipoproteins (Lp B:E) and the amount of apoB in apoE-containing lipoproteins (Lp E:B). From the Lp B:E and Lp E:B concentrations, the molar ratio of apoE to apoB in lipoproteins containing apoB and/or apoE in plasma can be determined. The methodology is fast, specific, and sensitive and should prove extremely useful in further categorizing lipoproteins and characterizing their behavior. In applying this method to clinical groupings of normo- and hyperlipidemia, we found that the plasma triglyceride level correlated with the apoE and Lp B:E concentrations in plasma, while the total cholesterol level correlated with the apoB and Lp E:B levels.

Application of anticancer agent embolism in Miles' operation

Presented in this paper is a report of the prospective studies on rectal cancer. By using the method of anticancer agent gelatin sponge to form embolism and by ligating the bilateral arteria iliaca internal, we performed Miles' operation on 64 cases of rectal cancer. Only 24 cases in the control group had Miles' operation. The amount of blood transfused during operation, duration of operation, days of hospitalization, infection rate of incision on the peritoneum, and relapse rate in treated group were significantly different from those in the control group (P < 0.05).

MELAS syndrome associated with diabetes mellitus and hyperthyroidism: a case report from Taiwan

MELAS syndrome is a form of mitochondrial myopathy with manifestations of seizure, stroke-like syndrome, lactic acidosis, ragged red muscle fibres and mitochondrial encephalopathy. The syndrome has been reported in association with a variety of endocrine and metabolic disorders including diabetes mellitus (DM), hypothalamo-pituitary hypofunction, hypothalamic growth hormone deficiency and delayed puberty. Mitochondrial DNA (mtDNA) point mutation may be the major pathological defect. However, association of MELAS syndrome with hyperthyroidism has not previously been reported. A case is reported from Taiwan of a 32-year-old woman suffering from MELAS syndrome with associated DM and hyperthyroidism. When the latter was diagnosed in April 1988, the patient underwent subtotal thyroidectomy. There was no family history of thyroid disease. Because of repeated seizures, she had computed tomography (CT) and magnetic resonance imaging (MRI) of the brain which showed focal, low-density lesions over the cerebral hemispheres. Both serum and cerebral spinal fluid lactic acid levels were elevated. Mild elevations of serum T4 and T3 and a high titre of TSH receptor antibody were still present. Hyperglycaemia was noted during hospitalization and DM confirmed by oral glucose tolerance test. Muscle biopsy showed ragged red fibres. DNA analysis showed an A-to-G transition at the 3243rd nucleotide position of the tRNA(Leu(UUR)) gene of the mtDNA from the patient. Quantitative polymerase chain reaction (PCR) and restriction analysis revealed that about 60% of the blood mtDNA was of mutant type. The patient received antithyroid drugs for hyperthyroidism, diet control for DM and anti-epileptic drugs for seizure.

A double-blind comparison of once-daily metoprolol controlled-release and atenolol in the treatment of Chinese patients with mild to moderate hypertension

The efficacy and tolerability of controlled-release metoprolol (metoprolol CR/ZOK), 100-200 mg, and atenolol, 50-100 mg, once daily was compared in Chinese patients with mild to moderate essential hypertension. The study was of a randomized, double-blind, two-way crossover design. The active treatment periods lasted 4 weeks each and were preceded by a 4-week placebo run-in period. The two double-blind phases were separated by a 2-week washout period on placebo. Blood pressures and heart rates were measured at rest in each 2-week visit and during exercise at the end of each treatment period. Twenty-four patients (M/F = 14/10) were valid for efficacy analysis. Their ages ranged from 39 to 68, with a mean of 53.5 years. The rest supine blood pressure and heart rate before active treatment was 160 +/- 15/106 +/- 6 mmHg and 75 +/- 14 beats/min (mean +/- SD), respectively. A responder was defined as exhibiting a supine diastolic blood pressure < or = 90 mmHg or a supine diastolic blood pressure reduction of at least 10% of the baseline level. Both agents had high response rate: 88% and 92% of all patients responded to metoprolol CR/ZOK and atenolol, respectively. Both active treatments considerably reduced resting systolic and diastolic blood pressures and heart rates as compared with baseline (p < 0.001), respectively. With controlled-release metoprolol, a more pronounced beta 1 blockade was obtained than with atenolol, which was expressed as a significant reduction in exercise-induced heart rate at the highest comparable workload compared with placebo (p < 0.05). These findings are compatible with those reported from western populations.

[The design and application of speech signal processing system by computer in stomatology.]

In this study we established a computer bases on Speech Signal Processing System and changes of formant frequencies of the vowel/i/accompany the changes in the oral cavity after maxillary surgery and prosthodontic reconstruction.The study found the F1 for vowel/i/has no change,while the F2 peak significantly shifted between the preprosthetic and postprosthetic speaking condition after anterior resection of relative energy error value and the speech intelligible measured aurally(P<0.05).

Tandem mass spectrometric characterization of a specific cysteic acid residue in oxidized human apoprotein B-100

The oxidation of low density lipoprotein (LDL) in vivo may result in its unregulated uptake by macrophages, with the consequent accumulation of cholesterol that is characteristic of the development of atherosclerosis. This paper describes initial experiments to elucidate structural changes that occur in an in vitro model of LDL oxidation. LDL was isolated from human blood and oxidized in the presence of copper ion. Lipid was removed and the isolated apoprotein was subjected to tryptic hydrolysis. The hydrolysate was separated by high performance liquid chromatography and individual fractions were screened by amino acid analysis to detect cysteic acid residues. Appropriate fractions were analyzed by fast atom bombardment mass spectrometry and hybrid tandem mass spectrometry. In this manner a tryptic fragment was identified that corresponded to residues 4187-4195 (EELCTMFIR), in which the cysteine and methionine residues were oxidized to cysteic acid and methionine sulfoxide, respectively. Identical analysis of LDL not subjected to in vitro oxidation revealed no evidence for this oxidized peptide. Earlier work established a surface location for this cysteine residue (Cys24) on the LDL particle, which suggested that its modification may significantly affect the properties of LDL, such as the propensity to intermolecular interaction via disulfide bridges. The analytical protocol developed here (involving proteolysis, screening of peptide fragments, and tandem mass spectrometry analysis) constitutes a strategy of general applicability to the characterization of targeted modifications of large proteins via mass spectrometry.

Impact of decreased serum transaminase levels on the evaluation of viral hepatitis in hemodialysis patients

The value of serum transaminases (ST) in evaluating hepatitis B (HBV) and C (HCV) infection was studied in 217 hemodialysis (HD) patients and 804 normal controls. Mean serum aspartate aminotransferase (AST) was 22.3 (22.0-22.7) and 22.6 (21.6-23.6) IU/l or 0.371 (0.366-0.378) and 0.376 (0.36-0.393) mu kat/l in controls and HD patients, respectively (nonsignificant), while mean serum alanine aminotransferase (ALT) was 20.3 (19.9-20.7) and 16.3 (15.3-17.3) IU/l or 0.338 (0.331-0.345) and 0.271 (0.255-0.288) mu kat/l in these two groups (p < 0.001). However, both AST and ALT became significantly depressed in HD patients after adjusting for age, gender, HBV surface antigen (HBsAg) and anti-HCV. The usual practice of regarding AST and ALT as being 'abnormal' in evaluating viral hepatitis when they exceeded the upper reference range (40 and 46 IU/l or 0.666 and 0.766 mu kat/l in our laboratory) was then critically assessed by the receiver operating characteristic (ROC) curve. ROC analysis showed that ST was useless in detecting HBsAg, while the best cutoff point for detecting the presence of anti-HCV was 18 IU/l (0.3 mu kat/l) for AST and 16 IU/l (0.266 mu kat/l) for ALT in HD patients, respectively. These are considerably lower than the conventional criteria for an 'abnormal' ST. We conclude that ST are decreased in HD patients and that the cutoff value of ST for detecting HCV should be set at lower levels to enhance their diagnostic yield.

Insulin autoimmune syndrome in a patient with methimazole and carbimazole-treated Graves' disease: a case report

Insulin autoimmune syndrome (IAS) includes fasting or reactive hypoglycemia, hyperinsulinemia and the presence of insulin-binding antibodies in patients who have never been exposed to exogenous insulin. The report concerns a 34-year-old male patient with Graves' disease who had history of having taken methimazole for two months, without any consequence, 4 years previously. However, when methimazole was again administered for three weeks followed by a week of carbimazole, the patient suffered hypoglycemia 4 times during the next 4 weeks. He denied history of diabetes mellitus (DM), of taking any oral hypoglycemic agent or of having received insulin injection. Laboratory data showed total serum insulin level > 320 microU/mL, free insulin 55 microU/mL and insulin antibody 88.3%. Oral glucose tolerance test (OGTT) revealed DM pattern. Since the patient had history of allergy to anti-thyroid drugs before this event, so he was treated with radioiodine (131I). There was no episode of hypoglycemic attack during 15 months of follow-up.

Glutamate-, GABA-, and GAD-immunoreactivities co-localize in bipolar cells of tiger salamander retina

The presence of inhibitory bipolar cells in salamander retina was investigated by a comparative analysis of the distribution of glutamate- and GABA-immunoreactivities (GLU-IR; GABA-IR) using a postembedding immunocytochemical method. GLU-IR was found in virtually all photoreceptors, bipolar cells and ganglion cells, neuronal elements that transfer information vertically through the retina. GLU-IR also was found in numerous amacrine cells in the mid and proximal inner nuclear layer as well as in the cytoplasm of horizontal cells, while the nucleus of horizontal cells was either lightly labeled or not labeled at all. GLU-IR was found in the outer plexiform layer and intensely in the inner plexiform layer, in which there was no apparent sublamination. Forty-seven percent of Type IB bipolar cells in the distal inner nuclear layer and 13% of the displaced bipolar cells were GABA-IR. All bipolar cells were also GLU-IR, indicating that GABA-IR bipolar cells were a subset of GLU-IR bipolar cells rather than a separate population. About 12% of the Type IB bipolar cells were moderately GABA-IR and likely comprised a GABAergic subtype. GLU-IR levels in the presumed GABAergic bipolar cells were higher than in other purely GLU-IR bipolar cells suggesting that these GABA-IR bipolar cells are glutamatergic as well. All of the displaced bipolar cells were only lightly GABA-IR, indicating that displaced bipolar cells comprise a more homogeneous class of glutamatergic cell than orthotopic bipolar cells. GAD-IR co-localized with GABA-IR in orthotopic but not displaced bipolar cells, further supporting the idea that some orthotopic bipolar cells are GABAergic. A small proportion of bipolar cells in salamander retina contain relatively high levels of both GABA and glutamate. Co-release of these substances by bipolar cells could contribute to the "push-pull" modulation of ganglion cell responses.

Structure of human apolipoprotein D: locations of the intermolecular and intramolecular disulfide links

We have determined the primary structure of human apolipoprotein D (apoD) by aligning peptides derived from digestions by cyanogen bromide, trypsin, and chymotrypsin. Our results confirm the primary structure derived from cDNA [Drayna et al. (1986) J. Biol. Chem. 261, 16535-16539]. ApoD consists of 169 amino acid residues, including 5 cysteines. Tryptic peptide analysis indicated that Cys41 and Cys16 are joined by a disulfide bridge. Using a combination of manual Edman degradations and mass spectrometric analysis on a purified cluster of chymotryptic fragments, we identified an intramolecular disulfide bridge between Cys8 and Cys114 and an intermolecular bridge between Cys116 of apoD and Cys6 of apoA-II. In addition, sites of N-glycosylation were found at Asn45 and Asn78. Because apoD contains two intramolecular disulfide linkages and has a high content of proline to disrupt alpha-helical structures, formation of the amphipathic helical regions that characterize the other soluble apolipoproteins is unlikely. We conclude that apoD binds to lipoprotein surfaces through structures other than alpha-helices, such as disulfide links.

Immunoreactivity of apolipoprotein B-100 in oxidatively modified low density lipoprotein

Thirteen monoclonal antibodies (MAbs) against apolipoprotein B-100 (apo B) were used to analyze changes in immunoreactivity of human LDL resulting from oxidation mediated by cupric ions and oxygen. Decrease in immunoreactivity of oxidized LDL was demonstrated by competitive ELISA with MAbs 5F8, BL3, Mb43, 2G8, B3, B5, and BL7 for which the epitopes are located within residues 1-1297, 4235-4355, 4027-4081, 3728-4306, 2239-2331, 1854-1878, and in the vicinity of residue 2331, respectively. Immunoreactivity of the epitope B6 (2239-2331) increased during first 4 hours of oxidation and then diminished gradually. Epitope B1 (405-539) had slightly reduced immunoreactivity during first 8 h of LDL oxidation and then its minor increase was observed. MAb 12G10, specific to the epitope within apo B thrombin-digest fragment T4 (1-1297), displayed either weak or strong binding to LDL. LDL with weak binding pattern demonstrated significant increase in immunoreactivity upon oxidation. In contrast, LDL with strong binding pattern showed little to no change. Epitopes Mb47 (3441-3569) and 8G4 (1-1297) remained unchanged in oxidized LDL. Immunoreactivity of apo B-100 epitope recognized by MAb 4C11 (residues 2377-2658) was shown to be a function of oxidation time: it increased progressively up to 16 h and was stabilized for another 24 h of LDL oxidation. This epitope may be unmasked by LDL oxidation and may provide a useful immunochemical marker to monitor the extent of LDL oxidation.

Regulation of PG synthase by EGF and PDGF in human oral, breast, stomach, and fibrosarcoma cancer cell lines

Prostaglandins may inhibit or promote tumor cell replication, depending on the cell system that is investigated. In our laboratory, we have established and characterized four different specific human cancer cell lines. The objectives of this study were to examine and compare the prostaglandin endoperoxide synthase (PG synthase, EC 1.14.99.1) activity of these cell lines by measuring the conversion of arachidonate to 3H-PGE2 and 3H-PGF2 alpha. We found that the oral epidermal carcinoma cell line (OEC-M1) had a moderate degree of PG synthase activity. Enzyme activity could be partially blocked (statistically significant) by the addition of epidermal growth factor (EGF) at 20 ng/mL and almost completely inhibited by platelet-derived growth factor at (PDGF) 20 mU/mL. By contrast, we discovered that the human breast adenocarcinoma cell line (BC-M1) did not contain significant PG synthase, and enzyme activity could be significantly activated by the addition of epidermal growth factor at 20 ng/mL and platelet-derived growth factor at 20 mU/mL. We also found that the human stomach adenocarcinoma cell line (SCM-1) had a significant amount of PG synthase activity, and these PG synthase activities were not activated or inhibited by EGF at 20 ng/mL or PDGF at 20 mU/mL. Furthermore, the human fibrosarcoma (FS-M1) cell line also contained a moderate degree of PG synthase activity, which could be significantly inhibited by PDGF at 20 mU/mL but was not inhibited by EGF at 20 ng/mL. The results suggest that EGF and PDGF may be involved in the regulation of the PG synthase activities of human oral, breast, stomach, and fibrosarcoma cancer cells.

Rat C-reactive protein causes a charge modification of LDL and stimulates its degradation by macrophages

We have previously shown the binding of low-density lipoprotein (LDL) to immobilized rat C-reactive protein (CRP) and the formation of a fluid-phase complex between these two proteins. In this report we used immunoelectrophoresis and agarose gel electrophoresis to show increased anodic migration of the LDL particle as a result of the modification of LDL by rat CRP. The degradation of the modified 125I-LDL by rat peritoneal macrophages was increased more than twofold in the presence of rat CRP. The increase in rat CRP-mediated 125I-LDL degradation by macrophages was dependent on the concentrations of 125I-LDL and rat CRP. This increased 125I-LDL degradation was inhibited by phosphorylcholine. In contrast, the degradation of 125I-acetyl-LDL by macrophages was not affected by rat CRP, although acetylated LDL inhibited the rat CRP-stimulated degradation of 125I-LDL. Increasing concentrations of LDL did not affect the degradation of rat 125I-CRP by the macrophages, which suggested that the rat CRP and the modified LDL did not enter the cell as a complex. Our results suggested that the increased degradation of 125I-LDL was caused by the charge modification of 125I-LDL by rat CRP, due to a fluid-phase complex formation between 125I-LDL and rat CRP, and that the degradation involved the scavenger receptor present on the macrophages.

The healing of grafts combining freeze-dried and demineralized allogeneic bone in rabbits

The adjunctive role of demineralized bone matrix (DBM) in enhancing the incorporation of segmental freeze dried (FD)-allogeneic bone grafts has been studied in the rabbit ulna and fibula. The studies compared the healing patterns of fresh segmental autografts, FD-allografts, DBM-allografts, and FD-allografts supplemented at the graft-host junctions with FD- or DBM-allografts as particulates (ulna) or as segmental struts (fibula). The outcome was evaluated at five and ten weeks by a radiologic score, by biomechanical properties (breaking strength, energy to failure, stiffness), and histology. The ulnar autografts healed most rapidly (ten weeks = 100%), followed by DBM allografts (60%). By all criteria, FD-allografts were poorly incorporated (20-40%), and the process was not improved by supplements of FD- or DBM-particulate/strut bone. Histologically, the DBM component of composite fibular strut grafts was osteoinductive and united with host tissues within 35 days. The contiguous FD-allograft struts were not incorporated, showing fibrocartilaginous nonunions and resorptive foci. While the addition of DBM does not protect FD-allograft integrity in the rabbit, segmental mineralized FD-allografts could provide mechanical support for some intervals until, in such composite grafts, osteoinductive processes produced biomechanically competent new bone.

Structure and orientation of apo B-100 peptides into a lipid bilayer

Peptides corresponding to lipid binding domains of Apo B-100 were synthesized, purified, and incubated with dimyristoylphosphatidylcholine (DMPC) liposomes. The secondary structure of the apo B-100 peptide-lipid complexes was evaluated by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Those peptides belonging to the hydrophobic "core" domain of apo B-100 when associated with phospholipids were rich in beta sheet structure; a predominant alpha helical conformation was shown to be associated with one peptide located in a surface region of apo B-100. IR dichroic spectra revealed, in the case of the "core" peptides, that the beta sheet component is the only oriented structure with respect to the phospholipid acyl chains. This orientation of the beta sheet was recently found in LDL particles after proteolytic digestion by trypsin (Goormaghtigh, E., Cabiaux, V., De Meutter, J., Rosseneu, M., and Ruysschaert, J. M., 1993, Biochemistry 32, 6104-6110). Altogether, the data suggest that beta sheet, present in a high proportion in the native apo B-100, is probably another protein structure in addition to the amphipathic helix which strongly interacts with the lipid outer layer surrounding the LDL particle.

[Workplace risk factors associated with eye syndrome in office workers]

Four large sealed office buildings were investigated to determine the relationship between the prevalence of sick building syndrome and the indoor air quality. Questionnaires were distributed to all building occupants. Respondents suffered from upper airway, eye, lower airway and many less specific complaints. Multivariate logistic regression analyses were conducted to assess workplace risk factors associated with eye syndrome. Working with visual display terminals, glare, use of desk lamp, fabric-covered partitions, new carpet, too dim, too bright and lack of openable windows correlated significantly with the prevalence of eye syndrome.

Complete membranous obstruction of the inferior vena cava: clinical characteristics of Chinese patients

OBJECTIVES

To analyse the clinical presentations of membranous-type Budd-Chiari syndrome and the long-term outcome of balloon angioplasty.

DESIGN

A case-control study. Patients who received abdominal sonography and were suspected of having hepatic venous outflow obstruction were advised to receive cardiac catheterization and angiography.

SETTING

Patients were collected from Chung Hisao Hospital and Chang Gung Medical Centre. Angioplasty was done at Chang Gung Medical Centre.

SUBJECTS

Seventeen patients who had the symptoms and signs of portal hypertension were suspected of having hepatic venous outflow obstruction after abdominal sonography and a radionuclide liver scan and eight of them were confirmed as having membranous-type obstruction.

INTERVENTIONS

Simultaneous catheterization and contrast angiography was performed via the right brachial and femoral veins. Angioplasty was performed afterwards.

MAIN OUTCOME MEASURES

The remission of clinical symptoms and signs and a decrease of the pressure gradient between the right atrium and inferior vena cava were used as indicators of successful intervention.

RESULTS

All patients had remarkable remission of symptoms and signs. The average pressure gradient between right atrium and inferior vena cava dropped from 16.5 +/- 1.6 to 6.5 +/- 1 mmHg (mean +/- SD).

CONCLUSION

The clinical presentations of membranous-type Budd-Chiari syndrome are somewhat different from hepatic vein occlusion. Balloon angioplasty may be a modality for curing this disease. A larger patient population is necessary to confirm this study.

[An investigation on public awareness, attitude and behavior toward drinking water quality in Taiwan]

The objective of this study was to investigate the public awareness, attitude and behavior toward drinking water quality. The results showed that (1) Overall, 80.6% of those responding to the survey rated their local drinking water quality as above average or better. (2) Even though most people were happy with the present quality of their drinking water, 79.2% of the public characterized themselves as concerned about encountering substances in drinking water in their lifetime that could lead to bad health effect or death. (3) 73.8% of the survey respondents never examined the water facilities for their own use.