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Biomedical subjects

Y Hara

Publications and source records attributed to Y Hara.

At least 397 records · Page 22Linked to original sources
PubMed1994

Mutation analysis of a Sandhoff disease patient in the Maronite community in Cyprus.

Sandhoff disease occurs in the Christian Maronite community in Cyprus, a community that established over a thousand years ago. Nowadays, this community comprises less than 1% of the whole population, and has been culturally and socially isolated. Cultured fibroblasts from a patient from this inbred group showed a beta-hexosaminidase beta subunit mRNA of apparently the normal size but of reduced quantity. A mutational analysis of cDNA obtained by polymerase chain reaction amplification of mRNA showed a deletion of A at nt 76 (counted from A of the initiation codon, ATG). The deletion results in a frame shift and a premature termination within 20 amino acids from the N-terminus of the normal mature enzyme protein. The patient was homozygous for the deletion. The 5'-end of the gene showed many discrepancies from the previously published sequence. We consider that these differences are probably polymorphisms of little functional significance, because the patient's fibroblasts generate decreased but stable mRNA and because some of these base changes were also found in the genes from control fibroblasts. An extensive evaluation of the prevalence of this mutant allele in this community is being initiated.

Base Sequence↗
PubMed1994

An approach to the hepatic hilus with marked fibrosis: a surgical technique for reconstruction of the bile duct with a benign stricture.

It is very difficult to approach the hepatic hilus safely in patients with common and/or hepatic bile duct strictures in which normal tissue has been replaced by scarred tissue with firm fibrous adhesions. In this report, we describe how eight patients with benign strictures of the bile duct underwent an operation which involved dividing the superior mesenteric and portal veins from the lower margin of the pancreas in a dorsal direction using a finger in a tunneling technique. The common bile duct, which was buried in scar tissue, was then explored, while the common and/or proper hepatic arteries in the hepatoduodenal ligament were confirmed, after transsection at the superior margin of the pancreas. Biliary reconstruction was successfully performed after resection of the constricted bile duct in all the patients, none of whom have experienced recurrence from 6 months to 5 years after the operation.

Aged↗
PubMed1994

Absence of right superior vena cava that was not detected by insertion of a pulmonary arterial catheter via the right internal jugular vein.

Pulmonary arterial catheter (PAC) placement under fluoroscopy is a useful and safe method to diagnose certain congenital cardiac anomalies [1]. However, when a PAC for intraoperative monitoring is placed without the aid of fluoroscopy, it may be inadvertently placed into anomalous veins. The following report presents a case of persistent left superior vena cava (PLSVC) with absence of right superior vena cava, which was not detected by a PAC inserted via the right internal jugular vein.

Aged↗
PubMed1994

Effect of magnesium and calcium on myocardial protection by cardioplegic solutions.

The cardioprotective effect of the magnesium and calcium content of hyperkalemic cardioplegic solutions was investigated using isolated rat hearts subjected to hypothermic ischemic arrest. Hearts were arrested for 180 minutes at 20 degrees C by administering a 3-minute infusion of cardioplegic solution containing various concentrations of magnesium and calcium. Treatment groups received solution with either 0, 8, or 16 mmol/L magnesium. For each of these magnesium concentrations, 0.1, 0.6, or 1.2 mmol/L calcium was also present in the solution. At each concentration of magnesium, the percentage recovery of aortic flow was dependent on the calcium concentration. The maximum percentage recovery of aortic flow was 67.9% +/- 2.3% (mean +/- standard error of the mean) in the Mg-free, 0.1 mmol/L Ca group, whereas it was 65.1% +/- 2.7% in the 8 mmol/L Mg, 0.1 mmol/L Ca group and 70.0% +/- 3.5% in the 16 mmol/L Mg, 0.6 mmol/L Ca group. No significant differences in the recovery of cardiac function and creatine kinase leakage were observed between the three groups. The findings suggested that the cardioprotective effect was dependent on the relative concentration of both magnesium and calcium, and that it is important to maintain an appropriate ionic balance in cardioplegic solutions.

Animals↗
PubMed1994

Racial and age-related differences in incidence and severity of focal autoimmune thyroiditis.

To determine possible racial and age-related differences of focal autoimmune thyroiditis between white and black Americans, autopsy material from American subjects was evaluated for incidence and severity of chronic lymphocytic thyroiditis. The overall incidence of lymphocytic infiltration in thyroid sections from subjects aged more than 20 years was 41.4% in white females, 20% in white males, 17.4% in black females, and 8.5% in black males. An increase to 54.8% in incidence of thyroiditis from the first decade onward was noted in white females older than 80 years of age. Age did not cause a remarkable increase in incidence of thyroiditis in white males, in black females, or black males. The susceptibility to chronic thyroiditis in American white males and females was almost the same as that of British white males and females. The incidence of thyroiditis in black females and males was similar to that in Japanese females and males. These findings showed clear racial differences in susceptibility to chronic thyroiditis.

Adult↗
PubMed1994

Expression of membrane alkaline phosphatase activity on gingival fibroblasts in chronic inflammatory periodontal disease.

We investigated the expression of membrane alkaline phosphatase (ALP) activity on fibroblasts in inflamed gingiva from 7 patients with adult periodontitis. ALP activity was ultrahistochemically detected by a cerium-based capture method. The degree of ALP activity was estimated by morphometric analysis of the percentage of the perimeter on which ALP reaction product was deposited. Fibroblasts in the non-inflammatory connective tissue were surrounded by bundles of collagen fibrils, and the majority of these fibroblasts showed ALP-negative or weakly ALP-positive reaction. By contrast, fibroblasts in the inflammatory connective tissue were either surrounded by a non-collagenous substance or in contact with inflammatory cells, and the majority of these fibroblasts showed a strong ALP-positive reaction. These results suggest that the expression of membrane ALP activity on gingival fibroblasts is induced by microenvironmental changes associated with the loss of contact between the cells and the extracellular collagenous matrix during inflammatory reactions.

Adult↗
PubMed1994

Antibacterial activity of epigallocatechin gallate against methicillin-resistant Staphylococcus aureus.

The antibacterial activity of epigallocatechin gallate (EGCg), a catechin, against 53 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) was evaluated and expressed as minimal inhibitory concentration (MIC). The MIC50 and MIC90 of the strains were found be 64 and 126 micrograms/ml, respectively by the microdilution method. A time-kill study using an isolate showed that EGCg appeared to be bacteriostatic at 1-2 x MIC and bactericidal at 6 x MIC against MRSA. In addition, the activity of EGCg was stable to various physical conditions including boiling or freezing. These findings suggest that EGCg could be a useful agent for treating MRSA infection.

Catechin↗
PubMed1994

[Effect of catechin on the ultrastructure of Trichophyton mentagrophytes].

The effects of (-) epigallocatechin gallate (EGCg) on the morphology of hyphae and conidia of Trichophyton mentagrophytes were examined using scanning and transmission electron microscopy. EGCg inhibited the germination of conidia and subsequent hyphal growth. After being treated with EGCg for 3 days, conidia showed morphological changes such as deformation, swelling, wrinkles, exfoliation of the surface layer and accumulation of granular, amorphous materials on the conidia and short hyphae surfaces. These morphological changes became apparent day by day. After 5 days, most of the ungerminating conidia were broken down. The hyphal cell walls were also exfoliated and the cytoplasm in most of the cells disappeared completely. Inner organellas were variable in size and shape. Many high electron dense particles, greatly enlarged vacuoles appeared in the cytoplasm. The degradation of cells occurred. These observations indicates that EGCg causes lysis of the conidia and hyphae. These findings suggest that EGCg may be used as an antidermatophytic agent against T. mentagrophytes infection.

Catechin↗
PubMed1994

[Inhibition of the infectivity of influenza virus by black tea extract].

We determined whether black tea extract inhibits the infectivity of influenza virus to mice. When mice were inoculated intranasally with 10(5.3) PFU influenza viruses (10(1.3) LD50), their body weight decreased and all died within 10 days. Whereas, when mice were inoculated i.n. with the mixture of influenza viruses and 2% (w/w) black tea extract, 5 min after mixing, all mice showed normal body-weight increase and survived. Neutralizing antibody to influenza virus was not detected in nine of 10 survived mice. The results indicate that black tea extract at beverage concentration (2% w/w) inhibits almost completely the infectivity of influenza virus to mice and that in vivo reversion of the tea-inactivated influenza virus does not occur.

Animals↗
PubMed1994

The effects of ketamine on conduction velocity and maximum rate of rise of action potential upstroke in guinea pig papillary muscles: comparison with quinidine.

Using standard microelectrode techniques, the effects of ketamine on the maximum rate of rise of action potential upstroke (Vmax) and the conduction velocity were examined and compared with the effects of quinidine, a sodium channel blocker, in isolated guinea pig papillary muscles. Both ketamine and quinidine decreased Vmax and the square of the conduction velocity in a concentration-dependent manner. The conduction slowing paralleled the decreases in Vmax, suggesting that the sodium current inhibition produced by these drugs is responsible for the conduction slowing. In the presence of quinidine, a train of stimulation after a quiescent period produced an exponential decline in Vmax, and the decrease in Vmax was enhanced by increasing stimulation frequency (i.e., use-dependent block). Ketamine significantly depressed Vmax of the first action potential after a long quiescent period (tonic block), and failed to produce a further decrease in Vmax during the subsequent train of stimulation. The decrease in Vmax was enhanced by simultaneous administration of ketamine and quinidine. Thus, ketamine decreases conduction velocity by inhibiting the sodium current. The mode of action on cardiac conduction is similar to that of quinidine, but different from that of volatile anesthetics which produce conduction slowing by impairing cell-to-cell coupling. However, ketamine produces a tonic block of the sodium channel while quinidine produces a use-dependent block. We conclude that ketamine should be administered with caution to patients receiving Class I antiarrhythmic drugs.

Action Potentials↗
PubMed1994

Antioxidative effects of black tea theaflavins and thearubigin on lipid peroxidation of rat liver homogenates induced by tert-butyl hydroperoxide.

The antioxidative activity of theaflavins (TFs) and thearubigin (TR) purified from the infusion of black tea leaves was examined using the tert-butyl hydroperoxide-induced lipid peroxidation of rat liver homogenates. The concentrations which produced 50% inhibition of lipid peroxidation (IC50) by theaflavin (TF), theaflavin monogallate-A (TFM-A), and TR were 4.88 x 10(-4), 4.09 x 10(-4), and 4.95 x 10(-4%) (w/v), respectively. The anti-oxidative activity of these compounds was higher than that of glutathione, L(+)-ascorbic acid, dl-alpha-tocopherol, butylated hydroxytoluene, butyl hydroxyanisole, etc., but was lower than the activity of (-)-epicatechin gallate, (-)-epigallocatechin, and (-)-epigallocatechin gallate. As to the IC50 in molarity, the antioxidative activity of TFM-A was the second highest among all the samples used in this study. The antioxidative activity of lyophilized tea infusions was compared. The activity of black tea was about as potent as that of green tea. These results suggest that black tea infusion containing TFs and TR could inhibit lipid peroxidation in biological conditions in the same way as green tea infusion containing epicatechins.

Animals↗
PubMed1994

Clinical evaluation of uniaxially oriented poly-L-lactide rod for fixation of experimental femoral diaphyseal fracture in immature cats.

Transverse diaphyseal fractures of the femur were experimentally made in immature cats, and were fixed by an intramedullary pinning technique using an uniaxially oriented poly-L-lactide (PLLA) rod, a biodegradable polymer. The healing process was evaluated radiographically and histologically. Formation of bony callus was completed in 8 weeks, and cortical bony union followed. The remodeling process was then observed form 12 to 16 weeks. The healing process was almost the same as when a metallic implant was used. Abundant periosteal callus formation may be attributable to the lower elasticity of the PLLA rod compared with metallic implants. Since no other abnormalities such as growth deformities were detected, it was concluded that the combined use of a uniaxially oriented PLLA rod and an external splint is clinically useful for the repair of diaphyseal fractures in immature cats.

Animals↗
PubMed1994

Prophylactic efficacy of milbemycin oxime against multiple infection of dogs with Dirofilaria immitis.

In order to examine the prophylactic effects of milbemycin oxime (MO) against Dirofilaria immitis infection, experiments were carried out under multiple infection with D. immitis. Ten filaria-free beagles of age 4 to 8 months were each inoculated with a total number of 480 larvae 12 times at intervals of 15 days over a period of 6 months, and MO was given monthly for the 6 months at a dose of 0.25 mg/kg. The infection rate in the medicated group of dogs was nil, this suggesting complete protection of the infection, while in the non-medicated control group it ranged from 6.5 to 14.8% (mean, 11.4%).

Animals↗
PubMed1994

Usefulness of computed tomography after myelography for surgery on dogs with cervical intervertebral disc protrusion.

Computed tomography after myelography (CTM) was performed pre- and postoperatively on four dogs diagnosed as having cervical intervertebral disc protrusion. The surgery was performed by ventral slot technique in all the cases. The direction of the ventral slot was precisely adjusted according to the location of the protruded discs as seen on CTM. Postoperative values for the transversal area of the spinal cord were greater than those measured preoperatively, suggesting effective decompression of the cord. The prognosis for these patients was excellent. In view of these results, it was considered that preoperative confirmation of the positional relationship between the spinal cord and the protruded disc by CTM was quite useful in planning the surgical technique for disc disease in the dog.

Animals↗
PubMed1994

Application of oriented poly-L-lactide screws for experimental Salter-Harris type 4 fracture in distal femoral condyle of the dog.

The clinical usefulness of biodegradable oriented poly-L-lactide (PLLA) screws for experimental Salter-Harris type 4 fracture in the distal femoral condyle of dogs was evaluated. Bony union of the osteotomized fragment of the condyle was almost completed radiographically and histologically within 1 to 2 months after surgery, suggesting that PLLA screws maintained strength long enough to fix the fragment until bone healing. At 4 to 6 months after surgery, minute fissures were histologically confirmed on the surface of the screw thread, suggesting the early stage of biodegradation and absorption of the polymer. During the observational period, no significant difference between the treated femur and the contralateral non-treated femur in either total femoral length or maximum condyle width was observed, indicating no growth disturbance in the treated femur. From these results it was concluded that the PLLA screw might be an ideal implant for the reduction and fixation of epiphyseal plate fractures such as Salter-Harris type 3 or type 4 fractures.

Animals↗
PubMed1994

Epigallocatechin gallate. The major causative agent of green tea-induced asthma.

We describe three patients who worked in green tea factories and developed asthmatic and nasal symptoms after exposure to green tea dust. To clarify what component(s) of green tea leaves might be responsible for causing asthma, we prepared catechins, the major components of green tea leaves. Epigallocatechin gallate (EGCg; MW: 458 daltons), a major catechin, was purified by high-performance liquid chromatography. Subjects included three patients with green tea-induced asthma, five asthmatics with no previous exposure to tea dust, and five healthy controls. It was found that all three patients exhibited an immediate skin and bronchial response to EGCg. Prausnitz-Küstner test with EGCg was also positive. However, none of the asthmatic and healthy controls showed a positive reaction. These results indicate that EGCg is a causative agent of green tea-induced asthma and suggest that an IgE-mediated response is, at least in part, responsible for causing this type of occupational asthma.

Asthma↗