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Biomedical subjects

J Ozaki

Publications and source records attributed to J Ozaki.

At least 19 recordsLinked to original sources
PubMed2000

The changes occurring after the Putti-Platt procedure using magnetic resonance imaging.

The purpose of this study is to evaluate the magnetic resonance imaging (MRI) following Putti-Platt procedure for recurrent anterior dislocation of the shoulder. Six shoulders of six patients who had received Putti-Platt procedure were evaluated by the MRI before and after operation. After the Putti-Platt procedure the subscapularis tendon was thickened and an increased signal area on T2-weighted images were observed in four patients. The area of subscapularis tendons after operation was increased maximally 3.46-fold and the volume was increased on average 1.51-fold. The course of subscapularis muscle fiber before operation was described as a mild arc, but changed to a straight line after the procedure in five patients. The findings in this study suggest that the Putti-Platt procedure leads to a remarkable increase in strength of subscapularis tendon and an improvement of laxity of subscapularis muscle. In conclusion, there is a good possibility that this procedure will increase the stability of the glenohumeral joint and be a successful treatment for recurrent anterior dislocation of the shoulder.

Adult↗
PubMed2000

Amino acid substitutions in a variant of IMP-1 metallo-beta-lactamase.

In the course of surveying for the carbapenem-hydrolyzing metallo-beta-lactamase gene bla(IMP) in pathogenic bacteria by the PCR method, we detected a gene encoding a variant metallo-beta-lactamase, designated IMP-3, which differed from IMP-1 by having low hydrolyzing activity for penicillins and carbapenems. PCR product direct sequencing of a 2.2-kb segment revealed that the gene bla(IMP-3) was located on a cassette inserted within a class I integron in the pMS390 plasmid. The 741-bp nucleotide sequence of bla(IMP-3) was identical to that of bla(IMP-1), except for seven base substitutions. Among these were two, at nucleotide positions 314 and 640, which caused amino acid alterations. Hybrid bla genes were constructed from bla(IMP-3) and bla(IMP-1) by recombinant DNA techniques, and beta-lactamases encoded by these genes were compared with those of the parents IMP-3 and IMP-1 under the same experimental conditions. The kinetic parameters indicated that the inefficient hydrolysis of benzylpenicillin, ampicillin, imipenem, and ceftazidime by IMP-3 was due to the substitution of glycine for serine at amino acid residue 196 in the mature enzyme. This alteration corresponded to the presence of guanine instead of an adenine at nucleotide position 640 of the bla(IMP-3) gene. This indicated that extension of the substrate profile in the metallo-beta-lactamase IMP-1 compared to IMP-3 is the result of a one-step single-base mutation, suggesting that the gene bla(IMP-3) is an ancestor of bla(IMP-1).

Amino Acid Substitution↗
PubMed2000

Comparison of arterial blood gases and acid-base balance in young and aged beagle dogs, with regard to postprandial alkaline tide.

Arterial blood pH and blood gas tensions were measured before and after feeding in seven young (1-year-old) and 6 aged (10 to 12 year-old) conscious beagle dogs with a portable "i-STAT" blood gas analyzer to obtain the fundamental physiological data on the laboratory dogs. Before feeding, arterial blood pH, HCO3- and base excess (BE) were 7.395 +/- 0.022, 20 +/- 1.0 mmol/L and -4 +/- 1.1 mmol/L in young dogs, and 7.408 +/- 0.031, 23 +/- 1.5 mmol/L and -2 +/- 1.8 mmol/L in aged ones. After feeding, the above values changed to 7.449 +/- 0.021, 25 +/- 1.1 and 1 +/- 1.3 in young dogs, and 7.456 +/- 0.022, 28 +/- 1.7 and 4 +/- 1.9 in aged ones. After feeding, each of the values for pH, HCO3- and BE was increased in comparison with those before feeding in both young and aged dogs, and alkalinization of blood, the alkaline tide, was observed in all healthy dogs. The values for PCO2 also rose from 33.6 +/- 1.91 to 36.7 +/- 1.95 (mmHg) in young dogs, and 36.4 +/- 2.97 to 40.3 +/- 3.06 (mmHg) in aged ones, and in 3 of 6 aged dogs slight hypoxia (PO2 < 80 mmHg) was noted. These changes in PCO2 and PO2 were considered to be due to compensatory hypoventilation for the alkalinization of blood. To confirm the cause of the alkaline tide phenomenon, we investigated the association of the alkaline tide with gastric acid secretion by cimetidine, an H2-blocker; and found that it was effective to inhibit postprandial alkaline tide in dogs. After feeding, ionized Ca concentration (iCa) was decreased inversely with an arterial blood pH increase in both young and aged dogs. The mean values of iCa in aged dogs after feeding was lower than those in young dogs. In the present experiments, it was demonstrated that in beagle dogs the acid-base balance and blood gas values were largely affected by feeding, especially in aged dogs. In case blood gases would be evaluated in toxicity studies, we should consider the influence of feeding and aging.

Acid-Base Equilibrium↗
PubMed1999

Enzymatic inactivation of major circulating forms of atrial and brain natriuretic peptides.

We compared the enzymatic inactivation of major circulating forms of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). Both ANP and BNP induced a significant increase in cyclic GMP (cGMP) formation in cultured epithelial cell line derived from porcine kidney, LLC-PK1. The cGMP formation stimulated by ANP in LLC-PK1 cells was significantly decreased by pre-treatment of the peptide with rat renal brush-border membranes, and the inactivation of ANP was inhibited by neutral endopeptidase inhibitors, phosphoramidon and S-thiorphan. BNP exhibited greater resistance to enzymatic inactivation than did ANP. In addition, phosphoramidon potentiated the natriuresis with a low dose (7.5 pmol min(-1) kg(-1)) of ANP but not of BNP in rats. These results suggest that enzymatic degradation of natriuretic peptides is highly dependent on peptide structure, and that the affinity of BNP to neutral endopeptidase is less than that of ANP.

Animals↗
PubMed1999

Bone mineral density of the shoulder joint in frozen shoulder.

The purpose of this study was to evaluate the osteopenia in several parts of the shoulder joint in a series of individuals suffering from frozen shoulder and to elucidate the pathogenesis. The bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DEXA). In 30 cases of frozen shoulder, 16 men and 14 women, BMD of the head of the humerus, greater tubercle of the humerus, surgical neck of the humerus, and neck of the scapula was evaluated. The average age of the male patients was 58.4 years and of the women, 59.5 years. At the neck of the scapula, there were no significant differences in any of the cases. However, there was a marked decrease in BMD at the proximal end of the humerus on the affected side of women. In contrast, men showed no significant difference between the affected and unaffected shoulders, suggesting that the degree of osteopenia remains low compared with women. Although frozen shoulder is a disease which may occur in both men and women, the loss of bone was conspicuous only in women. This may be due to the involvement of female hormones in alterations of bone in frozen shoulder, as in cases of osteoporosis, in addition to the originally low bone density in women. The degree of osteopenia of the proximal humerus with frozen shoulder was not correlated with the duration of the disease, range of motion of the shoulder joint, or patient's age.

Absorptiometry, Photon↗
PubMed1999

Resonance assignments, secondary structure and 15N relaxation data of the human transcriptional coactivator hMBF1 (57-148).

Multiprotein bridging factor 1 (MBF1) is a transcriptional coactivator that is thought to bridge between the TATA box-binding protein (TBP) and DNA binding regulatory factors, and is conserved from yeast to human. Human MBF1 (hMBF1) can bind to TBP and to the nuclear receptor Ad4BP, and is suggested to mediate Ad4BP-dependent transcriptional activation. Here we report the resonance assignments and secondary structure of hMBF1 (57-148) that contains both TBP binding and activator binding residues. 15N relaxation data were also obtained. As a result, hMBF1 (57-148) was shown to consist of flexible N-terminal residues and a C-terminal domain. The C-terminal domain contains four helices and a conserved C-terminal region.

Amino Acid Sequence↗
PubMed1999

Identification of the core domain and the secondary structure of the transcriptional coactivator MBF1.

BACKGROUND: Multiprotein bridging factor 1 (MBF1) is a transcriptional coactivator necessary for transcriptional activation caused by DNA binding activators, such as FTZ-F1 and GCN4. MBF1 bridges the DNA-binding regions of these activators and the TATA-box binding protein (TBP), suggesting that MBF1 functions by recruiting TBP to promoters where the activators are bound. In addition, MBF1 stimulates DNA binding activities of the activators to their recognition sites. To date, little is known about structures of coactivators that bind to TBP. RESULTS: The two-dimensional (2D) 1H-15N correlation spectrum of 15N labeled MBF1 indicated that MBF1 consists of both flexible and well structured parts. Limited digestion of MBF1 by alpha-chymotrypsin yielded a approximately 9 kDa fragment. N-terminal sequence analysis and NMR measurements revealed that this fragment originates from the C-terminal 80 residues of MBF1 and form a well structured C-terminal domain of MBF1, MBF1CTD. As previous deletion analyses have shown that MBF1CTD is capable of binding to TBP, it is suggested that MBF1CTD is the TBP binding domain of MBF1. Sequential assignments have been obtained by means of three-dimensional (3D) and four dimensional (4D) heteronuclear correlation spectroscopies, and then the secondary structure of MBF1CTD was determined. As a result, MBF1CTD was shown to contain four amphipathic helices and a conserved C-terminal region. Asp106 which is assumed to be responsible for the binding to TBP is located at the hydrophilic side of the third helix. CONCLUSIONS: Structural analyses revealed that MBF1 consists of two structurally different domains. A N-terminal region is indispensable for the binding to activators, and does not form a well defined structure. In contrast, the C-terminal 80 residues, which is capable of binding to TBP by itself, form a well-structured domain, MBF1CTD. MBF1CTD is made up of four amphipathic helices and a conserved C-terminal tail. A putative TBP binding residue is located on the hydrophilic surface of the third helix.

Amino Acid Sequence↗
PubMed1998

Morphologic changes in long head of biceps brachii in rotator cuff dysfunction.

Morphologic changes in the long head of the biceps brachii (LHB) and bicipital groove associated with cuff tears were studied in 170 cadavers. In specimens with minimum or moderate cuff tears, the primary finding was relative stenosis at the bicipital groove induced by enlargement of the LHB. However, this stenosis was not apparent in specimens with massive cuff tears and in these specimens, the medial wall of the groove exhibited wear and tear, a potential cause of LHB instability. We suggest that the long head of the biceps brachii muscle can potentially compensate for inadequate rotator cuff function. This increasing activity could lead to enlargement of the tendon and cause deterioration of the bicipital gliding mechanism.

Adult↗
PubMed1998

Electromyographic analysis of shoulder joint function of the biceps brachii muscle during isometric contraction.

Surface electromyography was performed for both heads of the biceps brachii in 11 healthy men while the muscles were under 30% maximum isometric shoulder flexion and abduction. Elbow related biceps activity was minimized by using a brace locked in neutral forearm rotation. Electromyographic activity was normalized as a percentage of maximal muscle contraction during 24 shoulder motions. Electromyographic activity was detected in all motions examined, suggesting that the biceps muscle acts as a flexor and an abductor of the shoulder. Both heads of the biceps muscle had higher activities during external rotation than during internal rotation for most motions. Activities of both heads increased with arm elevation, but showed little dependence on elbow position. The long head was still active during internal rotation of the shoulder. These findings also suggest that the biceps muscle is a flexor and an abductor of the shoulder, and that the long head can act as a humeral head stabilizer in superior and anterior directions. Muscle fatigue of the biceps and the deltoid muscle also was determined at 30% of maximum isometric flexion. All muscles had significantly decreased mean power frequency and turns count, and increased amplitude and integrated electromyography. The rate of decrease in mean power frequency was larger for the biceps than for the deltoid muscle, and the rate of increase in amplitude was larger for the long head of the biceps than for the short head or for the deltoid muscle. These findings suggest that the long head of the biceps must increase its mechanical output to keep the arm in elevation to a greater extent than do the short head and the deltoid muscle. This may be one of the causes of tendinitis or rupture of the long head.

Adolescent↗
PubMed1996

Pathomechanics and operative management of chronic frozen shoulder.

Forty-three patients who had recalcitrant chronic frozen shoulder were operated on between 1979 and 1993 and were followed up for an average of five years. The contracture of the coracohumeral ligament and the rotator interval appears to be the main lesion in chronic frozen shoulder. Release of the contracted structures, combined with appropriate exercise, relieved pain and restored motion of the shoulder in all patients.

Bursitis↗
PubMed1995

Function of supraspinatus muscle with torn cuff evaluated by magnetic resonance imaging.

An estimation of the residual function of the supraspinatus muscle after rotator cuff tear is useful to select the best operative method for repair of the torn cuff and to evaluate prognosis after surgery. The residual function of the supraspinatus muscle was studied by magnetic resonance imaging with motor unit potential amplitudes on electromyograms. Forty-three normal shoulders and 41 shoulders in patients with cuff tears were scanned by magnetic resonance imaging parallel to the long axis of the supraspinatus muscle. The ratio of the largest width of the supraspinatus muscle belly to the distance from the greater tubercle to the proximal end of the supraspinatus muscle was termed the supraspinatus muscle belly ratio. The linear bands of the supraspinatus muscle and the variation in the muscular signal intensity were classified into 3 grades. With a reduction in the motor unit potential amplitude, the supraspinatus muscle belly ratio became lower than 0.15. Additionally, the degree of appearance of the linear bands in the supraspinatus muscle belly increased, and the signal intensity became less uniform. The residual function of the supraspinatus muscle decreased when such morphologic changes were shown by magnetic resonance images. By analyzing these images, the best operative method for repairing a rotator cuff tear can be selected and the prognosis can be evaluated.

Adult↗
PubMed1994

Functional evidence for an apical ANP receptor in LLC-PK1 kidney epithelial cells.

The localization of natriuretic peptide receptors was studied in LLC-PK1 cell monolayers grown on a micro-porous membrane filter. The addition of alpha-human atrial natriuretic peptide (alpha-hANP) to the apical side of the cells produced a concentration-dependent increase in cyclic GMP (cGMP) formation, the extent of which was similar to that produced by the addition to the basolateral side. More cGMP was formed with alpha-hANP (1 and 100 nM) than with the C-type natriuretic peptide (100 nM). These findings indicate that the biologically active receptors with high efficacy for alpha-hANP are expressed in both the apical and basolateral membranes in LLC-PK1 cells.

Animals↗
PubMed1994

Simulation for the analysis of distorted pharmacodynamic data.

A simulation study was conducted to compare the performance of alternative approaches for analyzing the distorted pharmacodynamic data. The pharmacodynamic data were assumed to be obtained from the natriurertic peptide-type drug, where the diuretic effect arises from the hyperbolic (Emax) dose-response model and is biased by the dose-dependent hypotensive effect. The nonlinear mixed effect model (NONMEM) method enabled assessment of the effects of hemodynamics on the diuretic effects and also quantification of intrinsic diuretic activities, but the standard two-stage (STS) and naive pooled data (NPD) methods did not give accurate estimates. Both the STS and the NONMEM methods performed well for unbiased data arising from a one-compartment model with saturable (Michaelis-Menten) elimination, whereas the NPD method resulted in inaccurate estimates. The findings suggest that nonlinearity and/or bias problems result in poor estimation by NPD and STS analyses and that the NONMEM method is useful for analyzing such nonlinear and distorted pharmacodynamic data.

Antihypertensive Agents↗
PubMed1994

[Anatomical study on the atrophy of supraspinatus muscle belly with cuff tear].

We dissected the 76 shoulders in 38 cadavers to investigate changes in the supraspinatus muscle with a cuff tear and correlated these with age. We made a transverse section in the supraspinatus muscle and stained the section by the van Gieson method. Then we analyzed the changes in the supraspinatus muscle belly with the cuff tear, and by age, measuring the short and long diameter of a slice of the muscle belly and the area of tendon fiber. In the group with a normal cuff, there was a negative correlation between age and the short diameter of the slice of the supraspinatus muscle but no significant correlation between the age and the long diameter of the slice. In the group with a cuff tear, not only the short diameter but also the long diameter of the slice of the supraspinatus muscle decreased with increase in the length of the cuff defect. We concluded that measuring the long diameter of the slice of the supraspinatus muscle was more efficient than measuring the short diameter to evaluate muscle atrophy with a cuff tear. The area of the tendon in the slice increased with the length of cuff defect. The increased area of the tendon may have been responsible for reducing the elasticity in the supraspinatus muscle with a cuff tear.

Adult↗
PubMed1993

Synovial chondromatosis of the acromioclavicular joint. A case report.

Synovial chondromatosis involving the acromioclavicular joint is very rare. We report a case of synovial chondromatosis of the acromioclavicular joint associated with synovial cyst formation. Arthrography of the acromioclavicular joint revealed that the loose bodies lay within a synovial cyst which was in communication with the acromioclavicular joint. Synovectomy including removal of the synovial cyst and the loose bodies relieved symptoms completely. The patient was still pain- and recurrence-free at 4 years' follow-up.

Acromioclavicular Joint↗
PubMed1992

Tear of an ossified rotator cuff of the shoulder. A case report.

A 57-year-old man with an ossified rotator cuff with acute tears was treated by resecting the ruptured part, as well as the ossicles, and by repairing the massive cuff defect with Teflon felt. Six years after surgery, the pain had been completely relieved, and shoulder motion and muscle strength had been recovered.

Humans↗
PubMed1991

Characteristics of Staphylococcus aureus isolated from lesions of horses.

Seventy-six Staphylococcus aureus strains isolated from various lesions of horses were characterized. All of the 76 strains were identified as biotypes B (38.2%) and C (61.8%). Of 55 strains tested, 42 (76.4%) were differentiated into 7 coagulase types. Coagulase types V and VII were predominant in the metritis strains. Coagulase type II was found most frequently in the strains from phlegmon, dermatitis, sinusitis, empyema sinus, and nasal catarrh. Forty-two (55.3%) of the 76 strains were differentiated into 24 phage patterns. Twenty (58.8%) of 34 typable strains from metritis were lysed by the human group I phage 52, and group II phages 3A, 3C, 55 and 71. Forty-five (59.2%) of the 76 strains were resistant to 1 or more of 6 antibiotics. Strains resistant to penicillin G, irrespective of source, were most frequent (95.6%). Forty (93.0%) of 43 strains resistant to penicillin G alone or in combination with other antibiotics produced beta-lactamase. Only 8 (10.5%) of the 76 strains produced enterotoxins A (n = 2), B (n = 1) or C (n = 5), and they all were isolated from metritis. Only 1 strain isolated from phlegmon and 2 from metritis produced exfoliative toxin (ET) and toxic shock syndrome toxin-1 (TSST-1), respectively. The latter 2 strains also produced enterotoxin C. The results of the present study showed the first evidence of the presence of both ET- and TSST-1-producing S. aureus isolated from horses.

Animals↗