Specificity of antibodies to type II collagen in rheumatoid arthritis

To reassess the role of autoantibodies to type II collagen in the pathogenesis of diseases, we studied antibodies from patients with rheumatoid arthritis (RA) and from patients with relapsing polychondritis for species specificity and collagen type specificity, using an improved enzyme-linked immunosorbent assay. Antibodies were found in the sera of 15% of the RA patients and 50% of the relapsing polychondritis patients, as well as in the cartilage of 69% of the RA patients examined. Reaction with both homologous and heterologous type II collagens was common. Analysis of 19 selected RA sera revealed that autoantibodies were generally associated with specific antibodies to some species of heterologous type II collagen. In contrast, antibodies found in 4% of the non-RA controls were specific for either bovine or chick type II collagen. These findings indicate that autoantibody formation in RA and relapsing polychondritis may occur as a result of an immune response to heterologous type II collagen. However, since RA and relapsing polychondritis patient sera differed in their reactivity with the cyanogen bromide-digested peptides, it is possible that the clinical manifestation of collagen autoimmunity might be influenced by the epitope specificity of the antibodies.

Predictive factors for development of the no-reflow phenomenon in patients with reperfused anterior wall acute myocardial infarction

OBJECTIVES

We sought to elucidate the clinical factors related to the development of no-reflow phenomenon after successful coronary reperfusion in patients with an acute myocardial infarction (AMI).

BACKGROUND

Myocardial contrast echocardiography revealed that the no-reflow phenomenon is observed in some patients with a reperfused AMI, and those patients usually have poor functional and clinical outcomes. It is still unknown what clinical factors are related to the development of the no-reflow phenomenon.

METHODS

Myocardial contrast echocardiography was performed 15 min after successful coronary reperfusion therapy in 199 patients with an anterior wall AMI who underwent successful coronary reperfusion with primary coronary angioplasty within 24 h after the onset of AMI. Multiple logistic regression analysis was used to identify independent predictors of the no-reflow phenomenon.

RESULTS

Seventy-nine patients showed the no-reflow phenomenon. Univariate analysis indicated that pre-infarction angina within 48 h before symptom onset, Killip class, Thrombolysis in Myocardial Infarction flow grade 0 on the initial coronary angiogram, the number of abnormal Q-waves and the wall motion score (WMS) on the echocardiogram obtained at hospital admission are related to the no-reflow phenomenon. Multivariate logistic regression analysis revealed that all of these factors, except for Killip class, are independent predictive factors of the no-reflow phenomenon.

CONCLUSIONS

Development of the no-reflow phenomenon is related to the severity of myocardial damage (number of Q-waves), the size of the risk area (WMS) and the occlusion status of infarct-related artery. In addition, ischemic preconditioning (pre-infarction angina) seems to be the factor that attenuates the no-reflow phenomenon.

Dobutamine stress echocardiography predicts reversible dysfunction and quantitates the extent of irreversibly damaged myocardium after reperfusion of anterior myocardial infarction

OBJECTIVES

This study was designed to evaluate dobutamine stress echocardiography in identifying reversible dysfunction and assessing the extent of irreversibly damaged myocardium early in acute myocardial infarction.

BACKGROUND

Several experimental and clinical studies have suggested that dobutamine enhances contractile function of stunned or hibernating, or both, myocardium. It is important for clinical strategy to predict the magnitude of improvement in myocardial function early in acute myocardial infarction.

METHODS

We studied 21 patients with a reperfused first anterior myocardial infarction. Two-dimensional echocardiography was performed before and during dobutamine infusion (10 micrograms/kg body weight per min) at a mean of 3 days after the infarction. Follow-up echocardiography was performed at a mean of 25 days later. To assess segmental wall motion, we divided the left ventricle into 17 segments and assigned a wall motion abnormality score: 3 = dyskinesia or akinesia; 0 = normal. Improvement in wall motion was indicated by a decrease of at least one grade in segmental score. For quantitative assessment, the ratio of endocardial length showing dyskinesia or akinesia to a left ventricular endocardial length (akinetic length ratio) was determined in the apical long-axis view at each stage.

RESULTS

Sensitivity and specificity of dobutamine infusion in detecting improvement in wall motion at follow-up echocardiography were 83% (55 of 66 segments) and 86% (43 of 50 segments), respectively. Excellent correlation was found (r = 0.93, p < 0.001; absolute difference [mean +/- SD] 0.03 +/- 0.05) between the akinetic length ratios measured during dobutamine infusion and in the late convalescent stage.

CONCLUSIONS

In the early stage of acute myocardial infarction, low dose dobutamine stress echocardiography provides a useful method for predicting reversible dysfunction with excellent sensitivity and specificity and can also be used to quantitate the extent of irreversibly damaged myocardium.

Union of defects in the pars interarticularis of the lumbar spine in children and adolescents

Lumbar spondylolysis can heal with conservative treatment, but few attempts have been made to identify factors which may affect union of the defects in the pars. We have evaluated, retrospectively, the effects of prognostic variables on bony union of pars defects in 134 young patients less than 18 years of age with 239 defects of the pars who had been treated conservatively. All patients were evaluated by CT scans when first seen and more than six months later at follow-up.

The results showed that the spinal level and the stage of the defects were the predominant factors. The site of the defects in the pars, the presence or development of spondylolisthesis, the condition of the contralateral pars, the degree of lumbar lordosis and the degree of lumbar inclination all significantly affected union.

Down-regulation of CD40 and CD80 on B cells in patients with life-threatening systemic lupus erythematosus after successful treatment with rituximab

OBJECTIVES

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoreactive T cells and polyclonally activated B cells that produce autoantibodies. Five SLE patients who failed to respond to conventional immunosuppressants were treated with anti-CD20 antibody (rituximab) and their clinical manifestations and laboratory data were evaluated, including phenotypic analysis of B cells.

METHODS

Rituximab (375 mg/m(2)) was administered weekly for 2 weeks in five SLE patients who developed severe manifestations despite intensive treatment.

RESULTS

Rituximab resulted in rapid improvement (within several days) in clinical manifestations such as consciousness disorder, seizures, progressive sensory disorder, haemolytic crisis, cardiac function and laboratory data. The effects lasted 20 months in one patient; other patients were in remission for more than 6 months. Flow cytometric analysis revealed down-regulation of CD40 and CD80 expression on CD19-positive B cells 1 week after infusion of rituximab, and such down-regulation was seen for more than 7 months in two patients.

CONCLUSIONS

Our pilot study provides sufficient evidence of excellent tolerability and high efficacy of rituximab therapy in refractory SLE. Rituximab not only reduced B-cell number and IgG levels but down-regulated CD40 and CD80 on B cells, suggesting possible disturbance of T-cell activation through these costimulatory molecules. Reduction of both quantity and quality of B cells suggests that rituximab could improve the disease course in patients with refractory SLE.

Molecular phylogeny of macaques: implications of nucleotide sequences from an 896-base pair region of mitochondrial DNA

We determined the nucleotide sequences of an 896-base pair region of mitochondrial DNA (mtDNA) from 20 primates representing 13 species of macaques, a baboon, and a patas. We compared these sequences and the homologous sequences from four macaques and a human against each other and deduced the phylogenetic relationships of macaques. The results from the phylogenetic analyses revealed five groups among the macaques: (1) Barbary macaque, (2) two species of Sulawesi macaques, (3) Japanese, rhesus, Taiwanese, crab-eating, and stump-tailed macaques, (4) toque, pig-tailed, and lion-tailed macaques, and (5) Assamese and bonnet macaques. The phylogenetic position of Tibetan macaque remains ambiguous as to whether it belongs to the fourth or fifth group. Phylogenetic trees revealed that Barbary macaque diverged first from the other Asian macaques. Subsequently, the four groups of Asian macaques diverged from one another in a relatively short period of time. Within each group, most of the species diverged in a relatively short period of time following the divergence of the groups. Assuming that the Asian macaques diverged from the outgroup Barbary macaque three million years ago (MYA), the divergence times among groups of Asian macaques were estimated at 2.1-2.5 MYA and within groups at 1.4-2.2 MYA. The intraspecific nucleotide diversity observed among three rhesus macaques was so large that they did not form a monophyletic cluster in the phylogenetic trees. Instead, one of them formed a cluster with Japanese and Taiwanese macaques, whereas the other two formed a separate cluster. This implies that either polymorphisms of mtDNA sequences that existed before the divergence of these three species (ca. 700,000 years ago) have been retained in rhesus macaques or introgression has occurred among the three species.

Thermus aquaticus ATCC 33923 amylomaltase gene cloning and expression and enzyme characterization: production of cycloamylose

The amylomaltase gene of the thermophilic bacterium Thermus aquaticus ATCC 33923 was cloned and sequenced. The open reading frame of this gene consisted of 1,503 nucleotides and encoded a polypeptide that was 500 amino acids long and had a calculated molecular mass of 57,221 Da. The deduced amino acid sequence of the amylomaltase exhibited a high level of homology with the amino acid sequence of potato disproportionating enzyme (D-enzyme) (41%) but a low level of homology with the amino acid sequence of the Escherichia coli amylomaltase (19%). The amylomaltase gene was overexpressed in E. coli, and the enzyme was purified. This enzyme exhibited maximum activity at 75 degrees C in a 10-min reaction with maltotriose and was stable at temperatures up to 85 degrees C. When the enzyme acted on amylose, it catalyzed an intramolecular transglycosylation (cyclization) reaction which produced cyclic alpha-1,4-glucan (cycloamylose), like potato D-enzyme. The yield of cycloamylose produced from synthetic amylose with an average molecular mass of 110 kDa was 84%. However, the minimum degree of polymerization (DP) of the cycloamylose produced by T. aquaticus enzyme was 22, whereas the minimum DP of the cycloamylose produced by potato D-enzyme was 17. The T. aquaticus enzyme also catalyzed intermolecular transglycosylation of maltooligosaccharides. A detailed analysis of the activity of T. aquaticus ATCC 33923 amylomaltase with maltooligosaccharides indicated that the catalytic properties of this enzyme differ from those of E. coli amylomaltase and the plant D-enzyme.

Long-term potentiation of synaptic transmission in kitten visual cortex

1. Potentiation of synaptic transmission in visual cortex (areas 17 and 18) of kittens was investigated by extracellular recording of field potentials (FPs) and cortical units in cortical slices and whole-animal preparations. Responses to test stimulation (0.05 Hz) of the white matter (WM), lateral geniculate nucleus (LGN), and optic chiasm (OC) were documented before and after conditioning stimulation (2 Hz for 1 h). 2. In slice preparations of area 17, the FPs were always depressed during conditioning stimulation and were usually potentiated immediately after conditioning stimulation. Long-term potentiation (LTP) of FPs developed rapidly during the initial 1-2 h and continued to increase slowly for several hours after conditioning. 3. LTP of FPs was age dependent: LTP occurred most frequently (43/53) at the ages of 21-34 days, less frequently (4/7 and 5/11) at 14-20 and 35-41 days, and never (0/5 and 0/5) at 7-13 and 42-49 days. LTP age relationship determined as a ratio of the amplitudes of FPs after conditioning to that before conditioning was greater at 21-34 days (mean potentiation, 2.4 +/- 0.6) than at 14-20 or 35-41 days (1.7 +/- 0.5). 4. LTP was also documented by the shortening in latencies of orthodromic responses of cortical units sampled from 10 pairs of conditioned and unconditioned control slices. Unit responses were classified into mono- and polysynaptic groups according to the central delay, defined as the time required for their activation after the arrival of afferent impulses. The monosynaptic central delays were 0.22 ms shorter in conditioned (0.60 +/- 0.17 ms, n = 56) than in control slices (0.82 +/- 0.22 ms, n = 57); similarly, polysynaptic central delays were 0.66 ms smaller (1.70 +/- 0.43 ms, n = 51; and 2.36 +/- 0.79 ms, n = 51). Both differences were statistically significant (P less than 0.001). 5. There were laminar differences in LTP of mono- and polysynaptic transmission. LTP of monosynaptic transmission occurred throughout layers II-V (central delays shortened about 0.2 ms), whereas LTP of polysynaptic transmission was greatest in layer II (1.17 ms), moderate in layer III (0.66 ms), and slight in layer IV (0.3 ms). The time course of shortening in orthodromic latency in five polysynaptic units agreed with the time course of LTP of FP. 6. Location of synapses involved in LTP of synaptic transmission was studied by current source-density (CSD) analysis in slice preparations of area 17 during test stimulation of WM. CSD analysis demonstrated two components of current sinks (early and late), probably representing mono- and polysynaptic transmission.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of angina pectoris on myocardial protection in patients with reperfused anterior wall myocardial infarction: retrospective clinical evidence of "preconditioning"

OBJECTIVES

We examined whether angina pectoris occurring shortly before the onset of acute myocardial infarction can actually preserve postischemic left ventricular function in humans.

BACKGROUND

Experimental studies indicate that brief, transient episodes of ischemia render the heart very resistant to infarction from a subsequent sustained ischemic insult, an effect termed ischemic preconditioning. However, no clinical data are available concerning the implications of angina pectoris shortly before the onset of infarction in humans.

METHODS

We studied 84 patients with an acute anterior myocardial infarction. All patients had total occlusion of the proximal or medial portion of the left anterior descending coronary artery and achieved reflow within 6 h of onset. Patients were classified into three groups on the basis of duration of antecedent angina pectoris: group 1 = no angina (37 patients); group 2 = new angina pectoris occurring < or = 7 days of onset of infarction (22 patients); group 3 = angina pectoris beginning > 7 days before onset of infarction (25 patients). All patients underwent left ventriculography on the day of, and 28 days after, onset of infarction to determine ejection fraction and regional wall motion in the territory of the left anterior descending coronary artery by the centerline method.

RESULTS

Angiographic collateral flow grade was higher in group 3 than in groups 1 and 2 ([mean +/- SD] group 1 = 0.08 +/- 0.7, group 2 = 0.7 +/- 0.7, group 3 = 1.5 +/- 0.8). Although there were no differences in baseline ejection fraction and regional wall motion among the three groups, the degree of improvement was significantly greater in groups 2 and 3 than in group 1 (late minus baseline ejection fraction: group 1 = 0 +/- 8%, group 2 = 7 +/- 10% group 3 = 6 +/- 10% [p < 0.05 group 1 vs. groups 2 and 3]; late minus baseline regional wall motion: group 1 = 0.2 +/- 0.4, group 2 = 0.6 +/- 0.5, group 3 = 0.5 +/- 0.6 SD/chord [p < 0.05, group 1 vs. group 2]). When the study was limited to those patients with no or poor collateral flow (31 in group 1, 19 in group 2, 10 in group 3), only group 2 patients had a significant improvement in wall motion. Angina pectoris within 24 h before onset of infarction was more frequent in group 2 (82%) than group 3 (28%, p < 0.05).

CONCLUSIONS

Episodes of angina pectoris occurring shortly before the onset of infarction may preserve myocardial contractile function in reperfused myocardial infarction despite less support from collateral flow channels, although these are suggestive results in a limited number of patients.

Temporal changes in myocardial perfusion patterns in patients with reperfused anterior wall myocardial infarction. Their relation to myocardial viability

BACKGROUND

Several studies demonstrated ischemic microvascular damage in patients with acute myocardial infarction (AMI). In this study, myocardial contrast echocardiography (MCE) was used to assess the temporal changes in myocardial perfusion after reflow and to investigate the relation between MCE findings and myocardial viability.

METHODS AND RESULTS

MCE was performed with the intracoronary injection of sonicated microbubbles before and shortly after coronary reflow and 1 month later in 45 patients with anterior wall AMI. MCE before reflow was analyzed to determine the risk area as an area of contrast defect in the apical long-axis view. MCE images after reperfusion were analyzed to determine peak contrast intensity, which should be in proportion to the concentration of microbubbles within the microvasculature and in the infarcted and normal myocardium, and the ratio of these (PI ratio) was used to assess microvascular integrity. Areas of residual contrast defect were expressed as a ratio to those of left ventricular myocardial (RCD ratio) to assess the spatial extent of the MCE "no reflow." Regional wall motion (RWM, SD per chord) in the territory of the left anterior descending coronary artery was determined by the centerline method in both the acute and late stages. Although the PI ratio was extremely low shortly after coronary reflow, it increased in the late stage of AMI with the improvement in regional contractile function (RWM, -3.2 +/- 0.5 versus -2.6 +/- 1.0, P < .01; PI ratio, 0.44 +/- 0.25 versus 0.60 +/- 0.29, P < .01). Reduction in the RCD ratio was observed even in 15 patients with MCE no reflow in the acute stage (0.33 +/- 0.09 versus 0.16 +/- 0.11, P < .01). Then we investigated the relation between residual contractile function and microvascular integrity in the late stage. A significant correlation was found between the PI ratio and RWM (r = .73, P < .001) in the late stage of the AMI.

CONCLUSIONS

(1) Recovery from ischemic microvascular damage is generally observed in the late stage of AMI in association with improvement in myocardial contractile function. The degree of improvement in contractile function and microvascular integrity, however, varies among patients. (2) Contrast peak intensity in the late stage of infarction may provide a useful estimate of myocardial viability.

Flow-mediated dilatation of the basilar artery in vivo

Flow-mediated dilatation has been described mainly in peripheral conduit arteries. The goal of this study was to examine mechanisms and functional implications of flow-mediated dilatation in large cerebral arteries in vivo. Vessel diameter and velocity of blood flow through the basilar artery were measured using a cranial window in 45 anesthetized rats. Mean blood flow velocity through the basilar artery increased by 94 +/- 8% during unilateral common carotid artery occlusion and 203 +/- 13% during bilateral occlusion. Diameter of the basilar artery increased by 10 +/- 1% during unilateral common carotid artery occlusion and 29 +/- 2% during bilateral occlusion from control diameter of 275 +/- 8 microns. Vasodilatation appeared with a delay of 13 +/- 1 seconds after the onset of the increase in flow velocity. With systemic arterial pressure maintained at baseline levels, pressure in the basilar artery (servonull) decreased initially during carotid occlusion, and during dilatation of the basilar artery, pressure was restored partially toward normal. Indomethacin (10 mg/kg i.v.), topical application of tetrodotoxin (10(-6) M), NG-monomethyl L-arginine (5 x 10(-6) M), tetraethylammonium chloride (10(-2) M), glibenclamide (10(-5) M), SKF 525A (3 x 10(-5) M), and ouabain (10(-5) M) had no effect on flow-mediated dilatation.(ABSTRACT TRUNCATED AT 250 WORDS)

Serine racemase binds to PICK1: potential relevance to schizophrenia

Accumulating evidence from both genetic and clinico-pharmacological studies suggests that D-serine, an endogenous coagonist to the NMDA subtype glutamate receptor, may be implicated in schizophrenia (SZ). Although an association of genes for D-serine degradation, such as D-amino acid oxidase and G72, has been reported, a role for D-serine in SZ has been unclear. In this study, we identify and characterize protein interacting with C-kinase (PICK1) as a protein interactor of the D-serine synthesizing enzyme, serine racemase (SR). The binding of endogenous PICK1 and SR requires the PDZ domain of PICK1. The gene coding for PICK1 is located at chromosome 22q13, a region frequently linked to SZ. In a case-control association study using well-characterized Japanese subjects, we observe an association of the PICK1 gene with SZ, which is more prominent in disorganized SZ. Our findings implicating PICK1 as a susceptibility gene for SZ are consistent with a role for D-serine in the disease.

Microsurgical anatomy of the choroidal arteries: lateral and third ventricles

✓ The microsurgical anatomy of the arteries supplying the choroid plexus of the lateral and third ventricles was examined in 50 formalin-fixed cerebral hemispheres using × 3 to × 20 magnification. There was marked variation in the area of choroid plexus supplied by the choroidal arteries; however, the most common pattern was for the anterior choroidal artery (AChA) to supply a portion of the choroid plexus in the inferior horn and part of the atrium; the lateral posterior choroidal artery (LPChA) to supply a portion of the choroid plexus in the atrium and posterior part of the temporal horn and body; and the medial posterior choroidal artery (MPChA) to supply the choroid plexus in the roof of the third ventricle and a portion of that in the body of the lateral ventricle. The LPChA's and MPChA's occasionally sent branches to the choroid plexus on the contralateral side. The most frequent neural branches of the three choroidal arteries were as follows: AChA branches to the optic tract, cerebral peduncle, temporal lobe, and lateral geniculate body; LPChA branches to the thalamus, geniculate bodies, fornix, and cerebral peduncles; and MPChA branches to the thalamus, pineal body, cerebral peduncle, and tegmentum of the midbrain. Each of the choroidal arteries was divided into a cisternal and plexal segment. The cisternal segments were the most common site of origin of neural branches, but they also gave rise to some plexal branches. The plexal segments occasionally gave rise to neural branches.

Light transmittance characteristics of light-cured composite resins

OBJECTIVES

The purpose of this study was: (1) to examine the light transmittance characteristics of various shades of light-cured composite resins, and (2) to evaluate the effect of light transmittance characteristics on the color of the resins.

METHODS

Eleven shades of two composite resins were used. Specimens with four different thicknesses (0.5, 1.0, 2.0 and 3.0 mm) were prepared. The transmittance at wavelengths from 400 to 700 nm was measured. Also, the color values and the color differences among thicknesses of a specimen on the CIE L*a*b* color system were determined by a digital chroma meter. The differences in the transmittance, color values and color difference were determined by using a one-way analysis of variance (ANOVA) combined with a Tukey multiple-range test.

RESULTS

Significant differences were found in the wavelength dependence of transmittance between the two materials, and among shades of each material. The transmittances of the darker shades of one material were significantly lower at lower wavelengths than the other shades, but were nearly equal or significantly higher at higher wavelengths. There was a significant correlation between the changing ratio of transmittance and the color difference. Two materials showed significant differences in delta a* and delta b* of the chromatic component of color difference.

SIGNIFICANCE

The results of this study indicate that light transmittance characteristics, including the wavelength dependence, play an important role for the color of a composite resin. The significant difference in light transmittance characteristics among materials and shades will affect their clinical appearance.

Cerebral blood flow and brain function in hypertension

In mild hypertensive patients, regional cerebral blood flow, measured by positron emission tomography, was reduced in the frontal cortex and basal ganglia compared with normotensive patients. In moderate to severe hypertensive patients, cerebral oxygen metabolism was diminished, although the patients were neurologically intact. In elderly hypertensives, white matter vascular lesions on brain imaging were more frequent and cognitive function was impaired, compared with age-matched normotensives. In nontreated spontaneously hypertensive rats (SHR), local cerebral blood flow was decreased in the cortex and thalamus, compared with normotensive rats (NTR). Spatial memory and learning in maze tests were more impaired in aged SHR than in old NTR or young SHR. This impairment was related to decreased cerebral glucose utilization in the medial septal nucleus, hippocampus, and other regions of the brain. Reduced cerebral blood flow, increased media thickness of the cerebral arteries and impaired cognitive function in SHR were improved by long-term antihypertensive treatment. In humans as well as animals, long-standing hypertension per se leads to reductions in cerebral blood flow, metabolism, and cognitive function, each of which possibly may be improved by controlling hypertension with long-term antihypertensive treatment.

Esophageal stimulation by hydrochloric acid causes neurogenic inflammation in the airways in guinea pigs

To investigate whether tachykinins are released in the airways in response to stimulation of the esophagus, we studied the airway plasma extravasation induced by intraesophageal HCl in the presence or absence of neutral endopeptidase inhibitor phosphoramidon and NK1-receptor antagonist FK-888 in anesthetized guinea pigs. The airway plasma leakage was evaluated by measuring extravasated Evans blue dye in the animals pretreated with propranolol and atropine. Infusion of 1 N HCl into the esophagus significantly increased plasma extravasation in the trachea. Phosphoramidon significantly potentiated plasma extravasation in the trachea and main bronchi, whereas FK-888 significantly inhibited that extravasation in a dose-related manner. In the capsaicin-treated animals, airway plasma extravasation was completely inhibited even in the presence of phosphoramidon. Tracheal plasma extravasation potentiated by phosphoramidon was significantly inhibited in the bilateral vagotomized animals. These results suggest that 1) tachykinin-like substances are released to cause plasma extravasation in the airways as a result of intraesophageal HCl stimulation and 2) there are neural pathways communicating between the esophagus and airways, including the vagus nerve.

Impact of tranilast on restenosis after coronary angioplasty: tranilast restenosis following angioplasty trial (TREAT)

BACKGROUND

Tranilast is an antiallergic drug that suppresses the release of cytokines such as platelet-derived growth factor, transforming growth factor-beta1, and interleukin-1beta and prevents keloid formation after skin injury. Treatment with this drug reduced the restenosis rate after percutaneous transluminal coronary angioplasty in a preliminary study.

METHODS AND RESULTS

We conducted a multicenter, randomized, double-blind, placebo-controlled trial. A total of 255 patients with 289 lesions were randomly assigned to treatment with the oral administration of 600 mg/d tranilast, 300 mg/d tranilast, or a placebo for 3 months after successful angioplasty. Angiographic follow-up was done at 3 months, and a clinical follow-up examination was performed at 12 months. Two hundred ten (72.7%) lesions of 188 (73.7%) of the patients met the criteria and were eligible for the assessment of restenosis. The restenosis rates defined as >/=50% loss of the initial gain were 14.7% in the 600 mg/d tranilast group, 35.2% in the 300 mg/d tranilast group, and 46.5% in the placebo group (P <. 0001 for 600 mg/d tranilast vs placebo). The restenosis rates defined as percent diameter stenosis of >/=50% at follow-up were 17. 6% in the 600 mg/d tranilast group, 38.6% in the 300 mg/d tranilast group, and 39.4% in the placebo group (P =.005 for 600 mg/d tranilast vs placebo).

CONCLUSIONS

The oral administration of 600 mg/d of tranilast for 3 months markedly reduced the restenosis rate after percutaneous transluminal coronary angioplasty.

The number of active motor units and their firing rates in voluntary contraction of human brachialis muscle

To make clear the control mechanism of force generation in human muscle, the electrical activity of the brachialis muscle was studied at various levels of contraction force by recording single motor unit discharges as well as mass electromyograms (EMGs). The firing rate of motor units increased with force along an S-shaped curve. At low levels of force, motor units increased their firing rates steeply with force. At intermediate levels of force, each motor unit increased its firing rate linearly with force at lower rates. As the maximum of force was approached, the firing rate increased very steeply, reaching as high as 50 Hz or more. By applying a new method of statistical processing to mass EMGs, the number of active motor units and the size of action potential were estimated at each level of force. The number of active motor units increased monotonously with muscle force. Motor units recruited at high levels of force had larger amplitudes of action potentials than those recruited at lower levels. Calculations were made to determine how the relative contribution to an increase in muscle force is varied between recruitment and the increase in firing rate. The contribution of recruitment gradually decreased with the increase in force. Up to about 70% of the maximum force, recruitment is the major mechanism for increasing the force of contraction.

Potassium channel blockers and the effects of cromakalim on the smooth muscle of the guinea-pig bladder

1. The K+ channel blocking drugs tetraethylammonium Cl (TEA), procaine, 4-aminopyridine (4AP) and quinidine all produced concentration-dependent contractions of strips of smooth muscle from the guinea-pig urinary bladder. Apamin and glibenclamide caused little increase in the mechanical activity, and tolbutamide inhibited it. 2. TEA, procaine, 4AP, quinidine and apamin all increased the frequencies of spontaneous action potentials recorded with microelectrodes. TEA, quinidine and procaine all caused prolongation of the falling phase of the spike, and procaine and apamin completely abolished the after-hyperpolarization. 3. TEA and procaine increased K+ efflux from the tissue, an effect blocked by nifedipine. TEA and apamin increased, whereas quinidine, procaine and 4AP decreased K+ uptake. 4. Cromakalim caused a concentration-dependent hyperpolarization of the membrane, abolished spike activity, increased K+ fluxes and relaxed the smooth muscle. The relaxant effect of cromakalim was unaffected by apamin, and in its presence the effects of cromakalim on membrane potential and K+ fluxes were unchanged. Procaine abolished all the effects of cromakalim, and TEA at high concentrations reduced but did not abolish these effects. Quinidine reduced the effects of cromakalim on tension and membrane potential, but its actions were surmounted by higher concentrations of cromakalim. The effects of 4AP on tension and membrane properties were transitory, but it had some effects on the actions of cromakalim. Glibenclamide and tolbutamide reversed the relaxant effects of submaximal cromakalim concentrations, tolbutamide only transiently. 5. It is concluded that the channels opened by cromakalim are not those involved in generating the spike after-hyperpolarization. They have properties similar to the delayed rectifier K+ channels responsible for spike repolarization, and also are similar to the ATP-dependent K channels in vascular smooth muscle.

Survival-promoting functions of 14-3-3 proteins

The 14-3-3 proteins are a family of phosphoserine/phosphothreonine-binding molecules that control the function of a wide array of cellular proteins. We suggest that one function of 14-3-3 is to support cell survival. 14-3-3 proteins promote survival in part by antagonizing the activity of associated proapoptotic proteins, including Bad and apoptosis signal-regulating kinase 1 (ASK1). Indeed, expression of 14-3-3 inhibitor peptides in cells is sufficient to induce apoptosis. Interestingly, these 14-3-3 antagonist peptides can sensitize cells for effective killing by anticancer agents such as cisplatin. Thus, 14-3-3 may be part of the cellular machinery that maintains cell survival, and targeting 14-3-3-ligand interactions may be a useful strategy to enhance the efficacy of conventional anticancer agents.

Time course of functional improvement in stunned myocardium in risk area in patients with reperfused anterior infarction

BACKGROUND

The beneficial effect of coronary reflow on myocardial salvage may be assessed more accurately than in previous studies if the size of risk area is taken into account, particularly because the size of risk area varies significantly among patients. In this study, the risk area was determined with myocardial contrast echocardiography to investigate the time course of functional recovery of postischemic myocardium within the risk area in patients with reperfused anterior myocardial infarction.

METHODS AND RESULTS

The study population consisted of 21 patients with anterior myocardial infarction who achieved coronary reflow within 6 hours of onset by means of thrombolysis or coronary angioplasty. Myocardial contrast echocardiography was performed with the injection of hand-agitated Haemaccel (5 ml) into the right and left coronary arteries before coronary reflow, and the risk area was defined as the area of contrast perfusion defect in the apical long-axis view. The ratio of the endocardial length of abnormal contraction (dyskinesis/akinesis) segment to that of contrast defect segment (AS/CD) was determined at days 1, 2, 3, 7, 14, and 28 of reflow. Before reflow, the length of contrast defect correlated well with the segment length of dyskinesis/akinesis. The values for AS/CD in patients with successful reperfusion significantly and progressively decreased until day 14; 1.00 +/- 0.02 at day 1, 0.93 +/- 0.11 at day 2 (p < 0.05 versus day 1), 0.84 +/- 0.16 at day 3 (p < 0.05 versus day 2), 0.80 +/- 0.13 at day 7 (p < 0.01 versus day 2), 0.73 +/- 0.10 at day 14, and 0.72 +/- 0.10 at day 28. Greater improvement in function was obtained in patients reperfused within 4 hours than in those reperfused at > or = 4 hours (AS/CD at day 28, 0.64 +/- 0.12 versus 0.75 +/- 0.09, p < 0.05).

CONCLUSIONS

Thus, a significant amount of myocardium, an average of 28% in segment length of the risk area, is salvaged in patients with reperfused anterior myocardial infarction. Major functional improvement seems to be achieved within 14 days of reflow.

Flexural properties and impact strength of denture base polymer reinforced with woven glass fibers

OBJECTIVES

The present investigation was undertaken to determine the reinforcing effect of woven glass fibers on deflection, flexural strength, flexural modulus and impact strength of acrylic denture base polymer.

METHODS

Three silanized or unsilanized woven glass fibers were used. Specimens were made by heating the denture cure resin dough containing glass fibers, which were sheathed in the dough. Specimens with four different thicknesses and of five different types were made, incorporating the glass fiber. Three-point flexural test and flywheel type impact test were employed to determine the flexural properties and impact strength.

RESULTS

When specimens contained unsilanized glass fiber, the flexural strength in specimens of 1 and 2 mm thickness and the impact strength in specimens of 2 mm thickness were higher than those of specimens without glass fiber (p < 0.01). On the contrary, the flexural strength and deflection in specimens reinforced with silanized glass fiber of 1 mm thickness were significantly higher (p < 0.01, p < 0.05) than those of unreinforced specimens. Further, the impact strength in specimens reinforced with silanized glass fiber of 2 mm thickness was significantly higher (p < 0.01) than that of unreinforced specimens. Statistically significant differences were found in the flexural strength (p < 0.05) and in the impact strength (p < 0.01) when specimens of 4 mm thickness were reinforced with two or three unsilanized glass fibers.

SIGNIFICANCE

The reinforcement with glass fiber was effective in thin specimens, and the reinforcing effect increased with the increase of the number of glass fibers in the case of thick specimens.

Crystal structure of amylomaltase from thermus aquaticus, a glycosyltransferase catalysing the production of large cyclic glucans

Amylomaltase is involved in the metabolism of starch, one of the most important polysaccharides in nature. A unique feature of amylomaltase is its ability to catalyze the formation of cyclic amylose. In contrast to the well studied cyclodextrin glucanotransferases (CGTases), which synthesize cycloamylose with a ring size (degree of polymerization or DP) of 6-8, the amylomaltase from Thermus aquaticus produces cycloamyloses with a DP of 22 and higher. The crystal structure of amylomaltase from Thermus aquaticus was determined to 2.0 A resolution. It is a member of the alpha-amylase superfamily of enzymes, whose core structure consists of a (beta, alpha)(8) barrel. In amylomaltase, the 8-fold symmetry of this barrel is disrupted by several insertions between the barrel strands. The largest insertions are between the third and fifth barrel strands, where two insertions form subdomain B1, as well as between the second and third barrel strands, forming the alpha-helical subdomain B2. Whereas part of subdomain B1 is also present in other enzyme structures of the alpha-amylase superfamily, subdomain B2 is unique to amylomaltase. Remarkably, the C-terminal domain C, which is present in all related enzymes of the alpha-amylase family, is missing in amylomaltase. Amylomaltase shows a similar arrangement of the catalytic side-chains (two Asp residues and one Glu residue) as in previously characterized members of the alpha-amylase superfamily, indicating similar mechanisms of the glycosyl transfer reaction. In amylomaltase, a conserved loop of around eight amino acid residues is partially shielding the active center. This loop, which is well conserved among other amylomaltases, may sterically hinder the formation of small cyclic products.