The role of percutaneous transhepatic papillary balloon dilation in percutaneous choledochoscopic lithotomy

BACKGROUND

When choledochoscopic lithotomy with basket and electrohydraulic lithotripsy is used to remove intrahepatic duct stones, fragments or small stones usually remain in the bile duct that are too small to be captured with a basket.

METHODS

An attempt was made to remove stone fragments in 16 patients with intrahepatic duct stones by antegrade balloon dilation of the sphincter of Oddi with a conventional balloon catheter. After balloon dilation, remnant stones and sludge were pushed through the papilla with the choledochoscope.

RESULTS

Bile duct stones were completely removed in 12 of 16 patients (75%); stones were removed in 1 session. There was no clinical evidence of procedure-related pancreatitis or fatal complications.

CONCLUSIONS

Percutaneous transhepatic papillary balloon dilation of the sphincter of Oddi and clearance of remnant bile duct stones and stone fragments with the tip of choledochoscope is simple and effective in patients undergoing percutaneous transhepatic choledochoscopic lithotomy.

Efficiency of absorption and metabolic conversion of quercetin and its glucosides in human intestinal cell line Caco-2

The efficiency of intestinal absorption and metabolic conversion of quercetin aglycone and its glucosides, quercetin-4'-O-beta-D-glucoside (Q4'G), quercetin-3-O-beta-D-glucoside (Q3G), and quercetin-3,4'-di-O-beta-D-glucoside (Q3,4'G), was estimated by using Caco-2 cell monolayers as an intestinal epithelial cell model. Aglycone was significantly lost from the apical side, resulting in the appearance of free and conjugated forms of quercetin and those of isorhamnetin in the cellular extracts. In the basolateral solution, the conjugated form of quercetin was predominant and increased with the elapse of incubation. As compared with quercetin aglycone, none of the quercetin glucosides were absorbed efficiently from apical side. However, Q4'G yielded conjugated quercetin and isorhamnetin in basolateral solution at higher amounts than Q3G or Q3,4'G. Lipophilicity of Q4'G was found to be higher than that of Q3G or Q3,4'G. This suggests that lipophilicity contributes to the relatively efficient absorption of Q4'G. It is likely that the occurrence of hydrolysis enhances the efficiency of intestinal absorption and metabolic conversion of dietary quercetin glucosides.

Identification of quercetin 3-O-beta-D-glucuronide as an antioxidative metabolite in rat plasma after oral administration of quercetin

The potential beneficial effect of dietary quercetin (3,3',4',5,7-pentahydroxyflavone) has attracted much attention in relation to the prevention of cardiovascular disease. It is generally recognized that dietary quercetin is subject to metabolic conversion resulting in conjugated forms during absorption and circulation. However, no quercetin conjugates have yet been identified from biological fluids or tissues. In the present study, we isolated and characterized two quercetin conjugates from the plasma of quercetin-administered rats. The blood plasma was collected from 26 rats 30 min after oral administration of quercetin (250 mg/kg body weight), concentrated, dissolved in 2% acetic acid aqueous solution (pH 2.65), and extracted with ethyl acetate. Two compounds (P2, P3) were obtained from the extract by repeated reversed-phase HPLC. On the other hand, two quercetin glucuronides were synthesized chemically and identified as quercetin 3-O-beta-D-glucuronide (Q3GA) and quercetin 4'-O-beta-D-glucuronide (Q4'GA), as determined from FABMS, 1H- and 13C-NMR, and HMBC data. The retention times of P2 and P3 in the HPLC chromatogram corresponded to those of Q3GA and Q4'GA, respectively. FABMS data demonstrated that P2 and P3 are quercetin monoglucuronides. 1H-NMR data for P2 were completely in agreement with those for Q3GA. P2 was therefore identified as Q3GA. This is, to our knowledge, the first evidence that Q3GA accumulates in vivo after oral administration of quercetin. Q3GA is likely to act as an effective antioxidant in blood plasma low-density lipoprotein, because this conjugated metabolite was found to possess a substantial antioxidant effect on copper ion-induced oxidation of human plasma low-density lipoprotein as well as 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity.

The application of non-parametric statistical techniques to an ALARA programme

For the cost-effective reduction of occupational radiation dose (ORD) at nuclear power plants, it is necessary to identify what are the processes of repetitive high ORD during maintenance and repair operations. To identify the processes, the point values such as mean and median are generally used, but they sometimes lead to misjudgment since they cannot show other important characteristics such as dose distributions and frequencies of radiation jobs. As an alternative, the non-parametric analysis method is proposed, which effectively identifies the processes of repetitive high ORD. As a case study, the method is applied to ORD data of maintenance and repair processes at Kori Units 3 and 4 that are pressurised water reactors with 950 MWe capacity and have been operating since 1986 and 1987 respectively, in Korea and the method is demonstrated to be an efficient way of analysing the data.

NMR analytical approach to clarify the molecular mechanisms of the antioxidative and radical-scavenging activities of antioxidants in tea using 1,1-diphenyl-2-picrylhydrazyl

(+)-catechin, ethyl gallate, ascorbic acid, and alpha-tocopherol were reacted with 1,1-diphenyl-2-picrylhydrazyl (DPPH), and the reaction mixtures were subjected to 13C-nuclear magnetic resonance (NMR) analyses to clarify the molecular mechanisms of the antioxidative and radical-scavenging activities of each antioxidant. When ascorbic acid was reacted with DPPH, it was oxidized to dehydroascorbic acid by DPPH. When a mixture of ascorbic acid and (+)-catechin was reacted with DPPH, ascorbic acid scavenged DPPH radical faster than (+)-catechin. Ascorbic acid also scavenged DPPH radical faster than ethyl gallate and alpha-tocopherol. When (+)-catechin was reacted with DPPH, the B-ring of (+)-catechin changed to an o-quinone structure. However, it was reduced to (+)-catechin by ethyl gallate or alpha-tocopherol. alpha-Tocopherol and ethyl gallate had almost identical antioxidative activities. Therefore, the order of radical-scavenging ability (speed) suggested by our 13C NMR study was as follows: ascorbic acid > alpha-tocopherol = ethyl gallate > (+)-catechin.

Accumulation of quercetin conjugates in blood plasma after the short-term ingestion of onion by women

Quercetin is a typical flavonoid present mostly as glycosides in plant foods; it has attracted much attention for its potential beneficial effects in disease prevention. In this study, we examined human volunteers after the short-term ingestion of onion, a vegetable rich in quercetin glucosides. The subjects were served diets containing onion slices (quercetin equivalent: 67.6-93.6 mg/day) with meals for 1 wk. Quercetin was only found in glucuronidase-sulfatase-treated plasma, and its concentration after 10 h of fasting increased from 0.04 +/- 0.04 microM before the trial to 0.63 +/- 0.72 microM after the 1-wk trial. The quercetin content in low-density lipoprotein (LDL) after glucuronidase-sulfatase treatment corresponded to <1% of the alpha-tocopherol content. Human LDL isolated from the plasma after the trial showed little improvement of its resistance to copper ion-induced oxidation. It is therefore concluded that conjugated metabolites of quercetin accumulate exclusively in human blood plasma in the concentration range of 10(-7) approximately 10(-6) M after the short-term ingestion of vegetables rich in quercetin glucosides, although these metabolites are hardly incorporated into plasma LDL.

A Hyperbranched Poly(ethyleneimine) Grown on Surfaces

Aminosilylated substrate was treated with aziridines in order to prepare hyperbranched polymers on solid supports such as silicon wafer and fused silica. It is observed that the primary amine on the substrate is good enough to initiate the ring-opening polymerization of aziridine. Measuring the thickness of the film and the absolute density of the primary amine functionality shows that a very highly branched poly(ethyleneimine) is formed upon the reaction. The surface density of the primary amine functional group (-NH(2)) on the very top surface increased dramatically (from 3.5 amines/nm(2) to 66 amines/nm(2)). A protected aziridine, benzyl 1-aziridinecarboxylate, was employed for the stepwise growth of the film. Two step-processes, chain growth and deprotection, were successful in growing the molecular layer, and a linear chain was formed without branching. Copyright 2000 Academic Press.

Cytomegalovirus pneumonia: high-resolution CT findings in ten non-AIDS immunocompromised patients

OBJECTIVE

To describe the HRCT findings of cytomegalovirus (CMV) pneumonia in non-AIDS immunocompromised patients

MATERIALS AND METHODS

This retrospective study involved the ten all non-AIDS immunocompromised patients with biopsy-proven CMV pneumonia and without other pulmonary infection encountered at our Medical Center between January 1997 and May 1999. HRCT scans were retrospectively analysed by two chest radiologists and decisions regarding the findings were reached by consensus.

RESULTS

The most frequent CT pattern was ground-glass opacity, seen in all patients, with bilateral patchy (n = 8) and diffuse (n = 2) distribution. Other findings included poorly-defined small nodules (n = 9) and consolidation (n = 7). There was no zonal predominance. The small nodules, bilateral in eight cases and unilateral in one, were all located in the centrilobular region. Consolidation (n = 7), with patchy distribution, was bilateral in five of seven patients (71%). Pleural effusion and bilateral areas of thickened interlobular septa were seen in six patients (60%).

CONCLUSION

CMV pneumonia in non-AIDS immunocompromised patients appears on HRCT scans as bilateral mixed areas of ground-glass opacity, poorly defined centrilobular small nodules, and consolidation. Interlobular septal thickening and pleural effusion are frequently associated.

Inhibitory effect of quercetin metabolites and their related derivatives on copper ion-induced lipid peroxidation in human low-density lipoprotein

To determine the antioxidant activity of dietary quercetin (3,3',4', 5,7-pentahydroxyflavone) in the blood circulation, we measured the inhibitory effect of quercetin metabolites and their related derivatives on copper ion-induced lipid peroxidation of human low-density lipoprotein (LDL). Conjugated quercetin metabolites were prepared from the plasma of rat 1 h after oral administration of quercetin aglycone (40 micromol/rat). The rate of cholesteryl ester hydroperoxide (CE-OOH) accumulation and the rate of alpha-tocopherol consumption in mixtures of LDL solution (0.4 mg/ml) with equal volumes of this preparation were slower than the rates in mixtures of LDL with preparations from control rats. The concentrations of CE-OOH after 2 h oxidation in the mixtures of LDL with preparations of conjugated quercetin metabolites were significantly lower than those in the control preparation. It is therefore confirmed that conjugated quercetin metabolites have an inhibitory effect on copper ion-induced lipid peroxidation in human LDL. Quercetin 7-O-beta-glucopyranoside (Q7G) and rhamnetin (3,3',4', 5-tetrahydroxy-7-methoxyflavone) exerted strong inhibition and their effect continued even after complete consumption, similarly to quercetin aglycone. The effect of quercetin 3-O-beta-glucopyranoside (Q3G) did not continue after its complete consumption, indicating that the antioxidant mechanism of quercetin conjugates lacking a free hydroxyl group at the 3-position is different from that of the other quercetin conjugates. The result that 4'-O-beta-glucopyranoside (Q4'G) and isorhamnetin (3,4',5, 7-tetrahydroxy-3'-methoxyflavone) showed little inhibition implies that introduction of a conjugate group to the position of the dihydroxyl group in the B ring markedly decreases the inhibitory effect. The results of azo radical-induced lipid peroxidation of LDL and the measurement of free radical scavenging capacity using stable free radical, 1,1,-diphenyl-2-picrylhydrazyl, demonstrated that the o-dihydroxyl structure in the B ring is required to exert maximum free radical scavenging activity. It is therefore likely that conjugation occurs at least partly in positions other than the B ring during the process of metabolic conversion so that the inhibitory effect of dietary quercetin is retained in blood plasma after absorption.

Mini-detachable snare ligation for the treatment of esophageal varices

BACKGROUND

We manufactured and studied the usefulness of a newly designed mini-detachable snare in the treatment of esophageal varices. The use of a multiple rubber band ligator, although generally effective and well tolerated, has certain limitations, including high cost, reduced visual field, and inadvertent band release.

METHODS

We performed a prospective randomized controlled trial of the use of mini-detachable snare ligation vs. multiple band ligation in patients with recent or active esophageal variceal bleeding. The outcomes assessed were immediate hemostasis and rates of recurrent bleeding, eradication, and recurrence.

RESULTS

From March 1997 to October 1998, 103 patients were entered into this trial; 46 underwent mini-detachable snare ligations and 57 multiple band ligations. Among patients with active bleeding, hemostasis was achieved in 6 of 7 (86%) in the mini-detachable snare ligation group and 11 of 13 (85%) in multiple band ligation group. Recurrent bleeding after initial treatment occurred in 2 of 46 (5.5%) in the mini-detachable snare ligation group and 3 of 57 (5.3%) in the multiple band ligation group. Esophageal varices were eradicated or reduced to grade I in 4.8 +/- 2.1 and 4.5 +/- 1.9 sessions in the mini-detachable snare ligation group and multiple band ligation group, respectively. The recurrence rate was 5 of 46 (11%) and 6 of 57 (11%) in the mini-detachable snare ligation group and multiple band ligation group during a follow-up period of 6 and 16 months, respectively. No serious complication occurred in either group.

CONCLUSION

The mini-detachable snare is a new device that provides safe and effective treatment for esophageal varices that is comparable to multiple band ligation.

Antimicrobial activity of 4-hydroxybenzoic acid and trans 4-hydroxycinnamic acid isolated and identified from rice hull

Two antimicrobial substances in rice hull were isolated and identified as 4-hydroxybenzoic acid and trans 4-hydroxycinnamic acid by LC-MS, and 1H- and 13C-NMR. An evaluation of 50% inhibition of growth (IC50) revealed that the two substances had different inhibition profiles against various microorganisms. Most of the gram-positive and some gram-negative bacteria were sensitive to trans 4-hydroxycinnamic acid and 4-hydroxybenzoic acid at IC50 concentrations of 100-170 and 160 micrograms/ml, respectively.

Quercetin metabolites inhibit copper ion-induced lipid peroxidation in rat plasma

The oxidative susceptibility of plasma obtained from rats after intragastric administration of quercetin was studied to know whether or not quercetin acts as an in vivo antioxidant after metabolic conversion. Quercetin was raised in the rat blood plasma essentially as glucuronide and/or sulfate conjugates. The plasma obtained from rats after quercetin administration was more resistant against copper sulfate-induced lipid peroxidation than the control plasma on the basis of the accumulation of cholesteryl ester hydroperoxides and the consumption of alpha-tocopherol. The results strongly suggest that some conjugated metabolites of quercetin act as effective antioxidants when plasma is subject to metal ion-induced lipid peroxidation.

Wrist-driven prehension prosthesis for amputee patients with disarticulation of the thumb and index finger

Partial hand amputations may leave significant functional limitations that are difficult to ameliorate by either orthoses or prostheses. Disarticulation of the thumb and index finger at the metacarpophalangeal joint level and the range of motion of the three remaining fingers would be insufficient to provide any type of grasp. In cases like this, a cosmetic hand usually seems to be the best solution. This report describes the design and use of a wrist-driven prehension prosthesis that was applied to a patient and provided a considerable improvement in function and cosmesis.

Antioxidant activity of a novel vitamin E derivative, 2-(alpha-D glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol

A novel vitamin E derivative, 2-(alpha-D-glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol (TMG), has excellent water-solubility (> 1 x 10[3] mg/ml). The antioxidant activity of TMG was investigated. Kinetic studies of the inhibition of radical-chain reaction of methyl linoleate in solution demonstrated that the peroxyl radical-scavenging activity was not changed by the replacement of phytiyl side chain of vitamin E to glucosyl group. TMG acted as an effective inhibitor on lipid peroxidation of egg yolk phosphatidylcholine (PC)-liposomal suspension induced by a water-soluble and a lipid-soluble radical generator, 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN). Its effectiveness was higher than that of ascorbic acid (AsA) when liposomal suspension was exposed to a lipid-soluble radical generator, AMVN. TMG also showed an excellent antioxidant activity on cupric ion-induced lipid peroxidation of PC-liposomal suspension, and suppressed the oxidation of rat brain homogenate which contained trace level of iron ion. On the other hand, AsA acted as a prooxidant on both the cupric ion-induced liposomal peroxidation and the oxidation of rat brain homogenate. When human plasma was exposed to either AAPH or AMVN, the accumulation of cholesteryl ester hydroperoxides was retarded by the addition of TMG.

Interlimb interaction and stabilization of contralateral leg in isokinetic knee evaluation

OBJECTIVE

To determine if peak torque (PT) production during isokinetic knee testing is affected by the stabilization and movement patterns of the contralateral leg.

DESIGN

Repeated measure design.

INTERVENTION AND MAIN OUTCOME MEASURE

Thirty subjects participated in comparing the force outputs in relation to the movement pattern of both legs. Another group of 45 subjects volunteered to perform five maximal isokinetic extension-flexion contractions in each of three different knee testing conditions: (1) without stabilization of the contralateral leg; (2) with a bar in front of the ankle joint of the contralateral leg; (3) with the contralateral leg strapped just above the level of the malleoli and the muscles of that leg induced reciprocally to perform isometric contractions with respect to the testing leg. PT was used to compare the strength of three different conditions.

RESULTS

Significantly greater PT was measured when the contralateral leg of the subject was fixed and induced to contract reciprocally.

CONCLUSION

More rigorous standardization of isokinetic strength testing procedures is needed due to differences in PT production of knee muscles according to the stabilization and movement pattern of the contralateral leg.

Cis- and trans-linalool 3,7-oxides and methyl salicylate glycosides and (Z)-3-hexenyl beta-D-glucopyranoside as aroma precursors from tea leaves for oolong tea

Two new alcoholic aroma precursors, cis- and trans-linalool, 3,7-oxides 6-O-beta-D-apiofuranosyl-beta-D-glucopyranosides (1 and 2), as well as two already known compounds, (Z)-3-hexenyl beta-D-glucopyranoside (3) and methyl salicylate 6-O-beta-D-xylopyranosyl-beta-D-glucopyranoside (beta-primeveroside: 4), and another new monoterpendiol glycoside, 8-hydroxygeranyl beta-primeveroside (5) have recently been isolated as aroma precursors in tea leaves (Camellia sinensis var. sinensis cv. Maoxie) ready for oolong tea processing.

Cis- and trans-linalool 3,7-oxides and methyl salicylate glycosides and (Z)-3-hexenyl beta-D-glucopyranoside as aroma precursors from tea leaves for oolong tea

Two new alcoholic aroma precursors, cis- and trans-linalool, 3,7-oxides 6-O-beta-D-apiofuranosyl-beta-D-glucopyranosides (1 and 2), as well as two already known compounds, (Z)-3-hexenyl beta-D-glucopyranoside (3) and methyl salicylate 6-O-beta-D-xylopyranosyl-beta-D-glucopyranoside (beta-primeveroside: 4), and another new monoterpendiol glycoside, 8-hydroxygeranyl beta-primeveroside (5) have recently been isolated as aroma precursors in tea leaves (Camellia sinensis var. sinensis cv. Maoxie) ready for oolong tea processing.

The changes in muscle strength and relaxation time after a comprehensive rehabilitation program for patients with myotonic dystrophy

Myotonic dystrophy is a muscular disorder characterized by muscle weakness and myotonia. Myotonia manifests with abnormally slow relaxation after strong voluntary contraction of the muscles. In our previous study we reported that quinine sulfate provided therapeutic benefit to myotonia and a home exercise program based on muscle strengthening exercises improved muscle strength. The purpose of this study was to determine the effect of a multi-therapeutic program in patients with myotonic dystrophy. For six months, seven patients with myotonic dystrophy received heat therapy, were given psychologic intervention using relaxation techniques, were trained at home, and were given quinine sulfate. The changes in muscle strength and relaxation time between the post-six-months home exercise program combined with quinine sulfate therapy, and the post-six months multi-therapeutic program, were assessed from the first dorsal interossei, the elbow flexors, and the knee extensors. The results were as follows: 1) The mean muscle strength of the each of the three muscles after the six months multi-therapeutic program was improved but was not significant compared with the post-six-months home exercise program combined with quinine sulfate therapy. 2) The mean relaxation time of each of the three muscles after the six months multi-therapeutic program was significantly reduced compared with the home exercise program combined with quinine sulfate therapy. In conclusion, the multi-therapeutic program undertaken in this study was the better program for the patients with myotonic dystrophy.

DNA structural features responsible for sequence-dependent binding geometries of Hoechst 33258

The complexes of Hoechst 33258 with poly[d(A-T)2], poly[d(I-C)2], and poly[d(G-C)2], and poly[d(G-m5C)2] were studied using linear dichroism, CD, and fluorescence spectroscopies. The Hoechst-poly[d(I-C)2] complex, in which there is no guanine amino group protruding in the minor groove, exhibits spectroscopic properties that are very similar to those of the Hoechst-poly[d(A-T)2] complex. When bound to both of these polynucleotides, Hoechst exhibits an average orientation angle of near 45 degrees relative to the DNA helix axis for the long-axis polarized low-energy transition, a relatively strong positive induced CD, and a strong increase in fluorescence intensity--leading us to conclude that this molecule also binds in the minor groove of poly[d(I-C)2]. By contrast, when bound to poly[d(G-C)2] and poly[d(G-m5C)2], Hoechst shows a distinctively different behavior. The strongly negative reduced linear dichroism in the ligand absorption region is consistent with a model in which part of the Hoechst chromophore is intercalculated between DNA bases. From the low drug:base ratio onset of excitonic effects in the CD and fluorescence emission spectra, it is inferred that another part of the Hoechst molecule may sit in the major groove of poly[d(G-C)2] and poly[d(G-m5C)2] and preferentially stacks into dimers, though this tendency is strongly reduced for the latter polynucleotide. Based on these results, the importance of the interactions of Hoechst with the exocyclic amino group of guanine and the methyl group of cytosine in determining the binding modes are discussed.

A study on tea aroma formation mechanism: alcoholic aroma precursor amounts and glycosidase activity in parts of the tea plant

We have shown in molecular basis that alcoholic tea aroma is mainly formed by endogenous enzymatic hydrolysis of glycosidic aroma precursors during manufacturing. Amounts of alcoholic aroma precursor and glycosidase activity in each part of the tea shoot (Camellia sinensis var. sinensis cv Yabukita and a hybrid of var. assamica & var. sinensis cv Izumi) were indirectly measured by means of a crude enzyme assay. The aroma precursors were abundant in young leaves and decreased as the leaf aged. Glycosidase activity also decreased as leaves aged, but was high in stems.

Glycosidic aroma precursors of 2-phenylethyl and benzyl alcohols from Jasminum sambac flowers

Benzyl 6-O-beta-D-xylopyranosyl-beta-D-glucopyranoside (beta-primeveroside) (1), 2-phenylethyl beta-primeveroside (2), and 2-phenylethyl 6-O-alpha-L-rhamnopyranosyl-beta-D-glucopyranoside (beta-rutinoside) (3) were isolated as aroma precursors of benzyl alcohol and 2-phenylethanol from flower buds of Jasminum sambac Ait. The isolation was guided by an enzymatic hydrolysis and GC and GC-MS analyses.

Correlation of spinal mobility with the severity of chronic lower back pain

The purpose of this study is to show the correlation between the range of spinal motion and the severity of chronic lower back pain. The subjects of this study were 40 female patients with chronic lower back pain over a 6 months' duration. The range of spinal and hip joint motion was measured with a electrogoniometer, and the severity of back pain was evaluated with the Rolland's score and Pollard's pain disability index. Results were as follows. There was a correlation between the severity of pain and the range of lumbar lateral flexion, rotation, and extension (p < 0.05). Age, height, weight and body mass index had no correlation with the range of spinal motion. These results suggest that the range of lumbar spinal motion can be used as an objective measure for the evaluation of classifying chronic lower back pain patients and for planning and following their treatment.

Crystallization, molecular replacement solution, and refinement of tetrameric beta-amylase from sweet potato

Sweet potato beta-amylase is a tetramer of identical subunits, which are arranged to exhibit 222 molecular symmetry. Its subunit consists of 498 amino acid residues (Mr 55,880). It has been crystallized at room temperature using polyethylene glycol 1500 as precipitant. The crystals, growing to dimensions of 0.4 mm x 0.4 mm x 1.0 mm within 2 weeks, belong to the tetragonal space group P4(2)2(1)2 with unit cell dimensions of a = b = 129.63 A and c = 68.42 A. The asymmetric unit contains 1 subunit of beta-amylase, with a crystal volume per protein mass (VM) of 2.57 A3/Da and a solvent content of 52% by volume. The three-dimensional structure of the tetrameric beta-amylase from sweet potato has been determined by molecular replacement methods using the monomeric structure of soybean enzyme as the starting model. The refined subunit model contains 3,863 nonhydrogen protein atoms (488 amino acid residues) and 319 water oxygen atoms. The current R-value is 20.3% for data in the resolution range of 8-2.3 A (with 2 sigma cut-off) with good stereochemistry. The subunit structure of sweet potato beta-amylase (crystallized in the absence of alpha-cyclodextrin) is very similar to that of soybean beta-amylase (complexed with alpha-cyclodextrin). The root-mean-square (RMS) difference for 487 equivalent C alpha atoms of the two beta-amylases is 0.96 A. Each subunit of sweet potato beta-amylase is composed of a large (alpha/beta)8 core domain, a small one made up of three long loops [L3 (residues 91-150), L4 (residues 183-258), and L5 (residues 300-327)], and a long C-terminal loop formed by residues 445-493. Conserved Glu 187, believed to play an important role in catalysis, is located at the cleft between the (alpha/beta)8 barrel core and a small domain made up of three long loops (L3, L4, and L5). Conserved Cys 96, important in the inactivation of enzyme activity by sulfhydryl reagents, is located at the entrance of the (alpha/beta)8 barrel.

Exercise effect of modified contralateral stabilization bar during one-legged isokinetic exercise

We compared the electrical activities recorded from the muscles of the unexercised leg with changing the position of the contralateral stabilization bar to determine whether the degree of muscle contraction was influenced by the position of the bar during one-legged isokinetic exercise using an isokinetic dynamometer. The root mean square (RMS) values recorded from the medial hamstring sites of the unexercised legs showed a significantly higher value when the bar was located behind and on both in front of and behind the unexercised leg during one-legged extension exercise. Results from the isokinetic knee flexion exercise test indicated that a significantly greater RMS value was recorded from the vastus lateralis sites when the bar was located in front of and on both sides of the unexercised leg. During one-legged isokinetic extension-flexion exercise, the mean values of RMS voltage were greater when the bar was positioned in front of and on both sides of the unexercised leg in the vastus lateralis site. At the medial hamstring site, a greater value was noticed when the bar was located behind or on both sides.