Biomedical subjects

H Hosaka

Publications and source records attributed to H Hosaka.

At least 19 recordsLinked to original sources

PubMed2001

Photocontact dermatitis to ketoprofen.

A case of photocontact dermatitis from ketoprofen is described in a 19-year-old woman with a 3-day history of pruritic lesions on the right forearm. Physical examination revealed a 105 x 46 mm, dark reddish lesion consisting of edematous erythema and papules on the extensor aspect of the right forearm. In photopatch testing, positive reactions to as-is (Mohrus compress [Hisamitsu Pharmaceutical Co, Inc, Tosu, Japan]), ketorofen 1% in petrolatum (pet.), suprofen 1% pet., and tiaprofenic acid 1% pet. were seen. We must consider the anatomic sites on which nonsteroidal anti-inflammation medicaments are applied, as well as their effects.

Adult↗

PubMed2001

The structure of the archaebacterial ribosomal protein S7 and its possible interaction with 16S rRNA.

Ribosomal protein S7 is one of the ubiquitous components of the small subunit of the ribosome. It is a 16S rRNA-binding protein positioned close to the exit of the tRNA, and it plays a role in initiating assembly of the head of the 30S subunit. Previous structural analyses of eubacterial S7 have shown that it has a stable alpha-helix core and a flexible beta-arm. Unlike these eubacterial proteins, archaebacterial or eukaryotic S7 has an N-terminal extension of approximately 60 residues. The crystal structure of S7 from archaebacterium Pyrococcus horikoshii (PhoS7) has been determined at 2.1 A resolution. The final model of PhoS7 consists of six major alpha-helices, a short 3(10)-helix and two beta-stands. The major part (residues 18-45) of the N-terminal extension of PhoS7 reinforces the alpha-helical core by well-extended hydrophobic interactions, while the other part (residues 46-63) is not visible in the crystal and is possibly fixed only by interacting with 16S rRNA. These differences in the N-terminal extension as well as in the insertion (between alpha1 and alpha2) of the archaebacterial S7 structure from eubacterial S7 are such that they do not necessitate a major change in the structure of the currently available eubacterial 16S rRNA. Some of the inserted chains might pass through gaps formed by helices of the 16S rRNA.

Amino Acid Sequence↗

PubMed2001

Effect of long-term treatment with vanadate in drinking water on KK mice with genetic non-insulin-dependent diabetes mellitus.

The glucose-lowering effect of vanadate, ammonium metavanadate (AMV), on diabetic KK mice was examined. Five-week-old male KK mice were administrated with a solution of AMV via drinking water at concentrations of vanadium (V) with 0.1, 1.0, 10 and 100 microg/mL for a period of 10 wk, respectively. Body weight, consumption of food and water, and blood glucose levels was measured every week for 10 wk. The results showed that food consumption and body weight in the experimental groups were similar to those in the control group. A statistically significant decrease of drinking water consumption and blood glucose levels in the group treated with 100 microg V/mL was observed. The glucose tolerance in the vanadate-treated mice with 10 and 100 microg V/mL was remarkably improved compared with the control group. Biochemical analyses at the end of experiments demonstrated that a distinct tendency for the glucose and hemoglobin A1c (HbA1c) levels to decrease with vanadate treatment in the blood was also observed. The glutamic pyruvic transaminase, glutamic oxaloacetate transaminase, blood urea nitrogen, triglyceride, high-density lipoprotein, and total cholesterol levels in plasma were lower in the higher vanadium groups than those in the control group. These results indicate that vanadium effectively produced the glucose-lowering effect at a higher dose than that at a low dose of vanadium in drinking water, without any overt signs of toxicity.

Animals↗

PubMed2001

The repeatability of left ventricular volume assessment by a new ambulatory radionuclide monitoring system during head-up tilt.

The precise measurement of changes in left ventricular volume is important to elucidate the mechanisms of neurally mediated syncope. This study was conducted to determine whether or not a brand-new ambulatory radionuclide monitoring system (C-VEST system) can be clinically used to easily and precisely measure left ventricular volume and function in tilt testing. To assess the repeatability of the C-VEST system, 12 healthy volunteers (mean age 24+/-4 years old) underwent 20 minute head-up tilt testing and we measured the temporal changes in left ventricular volume and ejection fraction twice a day (first and second studies). To investigate the changes in the C-VEST measurements and the detector position in the first and second studies, tilt testing was performed with an 80-degree passive tilt, which is the same as the standard procedure used in diagnosing neurally mediated syncope. The coefficient of repeatability for both the C-VEST and detector position was well within the clinical range (coefficient of repeatability in left ventricular volume ranged from 1.7 to 2.8; coefficient of repeatability in the detector position ranged from 2.3 to 3.1). Precise evaluation of the left ventricular volume can be achieved by an ambulatory radionuclide monitoring system in tilt testing.

Adult↗

PubMed2000

Evaluation of immunological rapid urease testing for detection of Helicobacter pylori.

The aim of this study was to evaluate in clinical specimens the immunological rapid urease test (IRUT), a new diagnostic system for detection of Helicobacter pylori which employs a monoclonal antibody against Helicobacter pylori urease. Helicobacter pylori urease adsorbed on a solid-phase tip coated with a monoclonal antibody against Helicobacter pylori urease after 15 min of incubation with a gastric mucus sample solution was measured by the pH change of the urea solution inside the tip. The detection limit of Helicobacter pylori urease using this system was determined and compared with that of a commercially available rapid urease test. Clinical evaluation of the system was performed in 155 patients. The IRUT could detect 0.25 milli-international units (mIU) of Helicobacter pylori urease per milliliter in less than 20 min. If a patient with at least one positive result in a standard test for Helicobacter pylori was considered to be Helicobacter pylori positive, the sensitivity, specificity, positive and negative predictive values of the system were calculated as 95.2%, 98.9%, 98.4% and 96.8%, respectively. However, 10 of 19 Helicobacter pylori-positive patients in whom the pH change was less than 0.1 had negative results in at least one of the standard tests, whereas the IRUT correctly detected Helicobacter pylori in all but 3 of these 19 patients. The IRUT accurately determined the Helicobacter pylori status of 75 (98.7%) of 76 patients who had completed treatment. This system has high sensitivity for the detection of Helicobacter pylori, especially in patients with low urease activity.

Adult↗

PubMed2000

Self-cleavage of p2Sp1 RNA with Mg2+ and non-ionic detergent (Brij 58).

The precursor of an RNA molecule from T4-infected E. coli cells (p2Sp1 RNA) has the capacity to cleave itself at specific positions [(UpA (139-140) and CpA (170-171)], within a putative loop and stem structure. This sequence-specific cleavage requires at least a monovalent cation and non-ionic detergents. We studied the self-cleavage reaction of an RNA fragment (GUUUCGUACAAAC) (R1) with the sequence corresponding to the p2Sp1 RNA in the presence of Mg2+ and non-ionic detergents. It requires Mg2+ and is aided by a non-ionic detergent, Brij 58. The cleavage reaction is time, temperature, and pH-dependent. The cleavage occurs at the phosphodiester bond between UpA and CpA on the RNA fragment (GUUUCGUACAAAC) (R1). Furthermore, the maximum of cleavage of R1 occurs at a very low Mg2+ concentration (< or = 5 mM).

Cetomacrogol↗

PubMed2000

Simulation of body surface Laplacian maps during ventricular pacing in a 3D inhomogeneous heart-torso model.

A computer simulation study has been conducted to investigate the performance of body surface Laplacian maps (BSLMs) in localizing and imaging spatially separated myocardial electrical events. A cellular automaton model of ventricles simulates cardiac electrical activity using a two-site pacing protocol to induce dual simultaneously active myocardial electrical events. The heart model is embedded in a realistically shaped inhomogeneous volume conductor. The BSLMs are numerically computed from the induced electrical activity in the heart model. The present computer simulation results show that the BSLM can provide better separation and localization of two regional myocardial electrical events as compared with the body surface potential map (BSPM).

Artifacts↗

PubMed1999

The stem hairpin loop structure of p2Sp1 RNA is required for RNA-cleaving activity.

We studied the hairpin-loop structure of an RNA fragment (GUUUCGUACAAAC) (R13) with the sequence corresponding to the self-cleavage domain in the precursor of an RNA molecule from bacteriophage T4-infected Escherichia coli cells (p2Sp1 RNA). In order to determine the influence of the hairpin-loop structure on these sequence-specific cleavage reactions, we have synthesized oligoribonucleotides containing hairpin-loop, double-helical stem-loop, and single-stranded RNA structures. The cleavage was affected by the hairpin-loop structure. Furthermore, the helix-stem, which retains the thermodynamically extrastable stem hairpin-loop structures, is also important for the cleavage activity. However, the thermodynamically extrastable helix-stem structure reduced the cleavage activity of the adjacent UA and CA sequences at the helix-stem site. For the cleavage reactions of the RNA cleavage products, the R6 (ACAAAC), R7 (GUUUCGU), and R9 (GUUUCGUAC) mers from the parent RNA, R13 (GUUUCGUACAAAC), a very slight amount of cleavage product (2%) from the RNA 9 was observed, but no reaction occurred for the R6 and R7. We also describe the influences of the sequences (UA and CA) on the cleavage activity.

Base Sequence↗

PubMed1999

The three-dimensional structure of the RNA-binding domain of ribosomal protein L2; a protein at the peptidyl transferase center of the ribosome.

Ribosomal protein L2 is the largest protein component in the ribosome. It is located at or near the peptidyl transferase center and has been a prime candidate for the peptidyl transferase activity. It binds directly to 23S rRNA and plays a crucial role in its assembly. The three-dimensional structure of the RNA-binding domain of L2 from Bacillus stearothermophilus has been determined at 2.3 A resolution by X-ray crystallography using the selenomethionyl MAD method. The RNA-binding domain of L2 consists of two recurring motifs of approximately 70 residues each. The N-terminal domain (positions 60-130) is homologous to the OB-fold, and the C-terminal domain (positions 131-201) is homologous to the SH3-like barrel. Residues Arg86 and Arg155, which have been identified by mutation experiments to be involved in the 23S rRNA binding, are located at the gate of the interface region between the two domains. The molecular architecture suggests how this important protein has evolved from the ancient nucleic acid-binding proteins to create a 23S rRNA-binding domain in the very remote past.

Amino Acid Sequence↗

PubMed1999

Induction of urethral closure and inhibition of bladder contraction by continuous magnetic stimulation.

Magnetic stimulation has been considered to be a technique for stimulating nervous system noninvasively and it has been used for experimental and clinical testings on the central and peripheral nervous systems. However, commercially available magnetic stimulators can only discharge single pulses for less than several minutes because the coil soon overheats. We newly devised a continuous magnetic stimulator assuring long-time stimulation, and this study was designed to confirm whether continuous magnetic stimulation would result in urethral closure and inhibition of bladder contraction in anesthetized canine models. Twelve female beagle dogs, weighing 9 to 12 kg, were anesthetized with a mixture of alpha-chloralose and urethane. In six beagles, a 4 F microtip transducer was inserted transurethrally, and maximum intraurethral pressure was monitored. In the remaining six animals, urethra was ligated at the bladder neck and a 4 F double lumen catheter was inserted from the dome of the bladder to infuse physiological saline, monitoring iso-volumetric rhythmic bladder contraction. The stimulating coil, of which temperature was kept at 20-25 degrees C by the built-in cooling system, was placed on the ishio-rectal fossa to stimulate the pudendal nerve at 10 Hz. The intraurethral pressure increased by 69.1 +/- 27.8 cm H(2)O, and iso-volumetric rhythmic bladder contraction was inhibited during the stimulation with 80% (240 Joule) of maximum output. In conclusion, continuous magnetic stimulator was found effective for urethral closure and inhibition of bladder contraction. Neurourol. Urodynam. 18:505-510, 1999.

Animals↗

PubMed1999

Highly active antiretroviral therapy used to treat concurrent hepatitis B and human immunodeficiency virus infections.

We report a case of simultaneous infection with hepatitis B virus (HBV) and human immunodeficiency virus type 1 (HIV-1) in a 26-year-old Japanese homosexual man. He was admitted to our hospital for acute hepatitis caused by HBV. At that time, HIV-1antibody (Ab) was not detected in his serum. After 6 months, he was readmitted to our hospital for further examination of his liver because of confined liver enzyme abnormalities. Anti-HIV- Ab was detected in his serum by both enzyme immunosorbent assay (EIA) and particle agglutination (PA). His serum HIV-1 RNA level was 50 x 10(4) copies/ml and serum levels of HBV DNA polymerase (DNA-P) and HBV DNA were 6535cpm and 3 plus (>1000 copies/ml). His clinical course and laboratory data suggested progression from acute to chronic hepatitis related to coinfection with HIV-1. The diagnosis was chronic active hepatitis caused by HBV as an opportunistic infection due to coinfection with HIV-1. We began highly active antiretroviral therapy (HAART) because interferon (IFN) therapy was ineffective. HAART was started at an initial dosage of 600 mg zidovudine (AZT), 300 mg lamivudine (3TC), and 2400 mg indinavir (IDV) daily. After 4 weeks, the serum level of HBV DNA-polymerase (p) had decreased markedly to 37cpm and that of HIV-1 RNA had decreased to below the sensitivity threshold, indicating considerable suppression of the replication of these viruses by the treatment. But HBV DNA remained at low levels. Although the incidence of HBV infection in patients with HIV-1 infection has been reported to be high in the United States and Europe, simultaneous HBV and HIV-1 infection leading to persistent HBV infection is rare.

Adult↗

PubMed1999

Endoscopic urease sensor system for detecting Helicobacter pylori on gastric mucosa.

BACKGROUND: It is now accepted that the curing of Helicobacter pylori infection will result in healing of chronic active gastritis and will change the natural history of gastroduodenal ulcer disease. Both endoscopic observation and evaluation of H. pylori status of the stomach are necessary for diagnosis and treatment of such patients. We carried out a clinical evaluation of an endoscopic tube type urease sensor system for the detection of H. pylori on the gastric mucosa. The differential output of two pH-sensitive field effect transistors at the tip of the endoscopic tube reflects the pH change in a urea solution depending on the existence of urease. METHODS: In vitro experiments and clinical evaluation of the system were performed. Fifty-one patients who were suspected to have a gastroduodenal disorder were examined for H. pylori infection with this system, using the combination of histologic and bacteriologic examinations and rapid urease test as the references. RESULTS: Clinical sensitivity and specificity of this system were 26 of 28 (92.9%) and 22 of 23 (95.7%), respectively. A measurement at 1 site is completed in about 1 minute. Repetition of the procedure provides multi-site measurements. CONCLUSIONS: The present system makes possible quick on-site detection of H. pylori under endoscopic observation, with satisfactory sensitivity and specificity.

Adult↗

PubMed1999

Vitamin A toxicity secondary to excessive intake of yellow-green vegetables, liver and laver.

We report a case of sudden onset of vitamin A poisoning. A 20-year-old Japanese woman had been eating pumpkin and only a very limited amount of other foods on a daily basis for 2 years. She was overly concerned about weight reduction. Aurantiasis cutis and abnormal liver function tests were noted by her family doctor in 1995 when she was 18 years old. At that time, she stopped eating pumpkin. However, she secretly continued an excessive intake of other beta-carotene-rich vegetables, liver and laver for about 2 years. Two and one-half years after being seen by her family physician, she experienced sudden onset of low-grade fever, limb edema, cheilitis, dry skin, and headache. These symptoms worsened daily. A liver needle biopsy was performed, and it showed a normal portal tract along with fat-laden Ito cells in the space of Disse. A final diagnosis of vitamin A poisoning and hepatic injury secondary to an eating disorder was made. Her symptoms and serum beta-carotene levels returned to normal with successful adjustment of her diet.

Adult↗

PubMed1999

The relationship between modified pulse wave transit time and cardiovascular changes in isoflurane anesthetized dogs.

OBJECTIVE: To clarify the relationship between blood pressure and pulse wave transit time at the peripheral artery from the R wave of the electrocardiogram (m-PWTT), the effects of cardiovascular interventions on this relationship was evaluated. METHODS: Ten mongrel dogs were anesthetized by isoflurane inhalation, and catheter tip pressure transducers were inserted into the ascending aorta and at the bifurcation of abdominal aorta to measure central and peripheral pulse wave arrival. Pulse wave arrival at the ascending aorta from the R wave represents pre-ejection period (PEP) and pulse wave arrival between the ascending aorta and bifurcation of aorta represents pulse wave transit time (PWTT), thus m-PWTT = PEP + PWTT. Hypertension was induced by the continuous infusion of dobutamine and phenylephrine, and hypotension was induced by deepening isoflurane anesthesia, acute blood loss and nitroglycerine infusion. The relationship between timing components (PWTT, PEP, and m-PWTT) and blood pressure was recorded and analyzed by using the least squares method. RESULTS: The relationship between timing components (PWTT, PEP and, m-PWTT) and blood pressure was significant and highly correlated. When the change in blood pressure was due to the myocardial contractility, such as after dobutamine infusion, the relationship between all timing components and blood pressure was consistent and negative. However, when the change in blood pressure was due to the vasoactive agents, such as phenylephrine, the relationship between timing components and blood pressure was dependent on the reflex change in PEP. CONCLUSIONS: Change in m-PWTT is a good parameter to predict blood pressure changes, although the absolute blood pressure value cannot be obtained.

Anesthetics, Inhalation↗

PubMed1999

Wavelength and conduction inhomogeneity in each atrium in patients with isolated mitral valve disease and atrial fibrillation.

INTRODUCTION: Patients with mitral valve disease frequently have atrial fibrillation (AF), and the left atrium is presumed to be the primary atrium that develops AF. However, it is still not clear whether the electrophysiologic abnormalities responsible for AF are confined to the left atrium in this subset of patients. METHODS AND RESULTS: To examine the AF vulnerability of each atrium, we measured the wavelength and inhomogeneity of the conduction at the lateral right atrium, lateral left atrium, and Bachmann's bundle after defibrillation of AF in seven patients undergoing the maze procedure and mitral valve surgery for AF and isolated mitral valve disease, respectively (AF group). The data were compared with five coronary surgery patients in sinus rhythm (SR group). The wavelength in the AF group was significantly shorter (P < 0.05) than in the SR group not only at the lateral left atrium (225 +/- 62 vs 285 +/- 36 mm) but also at the lateral right atrium (214 +/- 54 vs 254 +/- 34 mm). The variation coefficient of the local maximum activation phase difference in the AF group (1.9 +/- 0.8 at the right atrium, 2.1 +/- 0.8 at the lateral left atrium, and 2.0 +/- 0.6 at Bachmann's bundle) was significantly greater (P < 0.05) than in the SR group at all atrial regions. CONCLUSION: AF vulnerability was not confined to the left atrium immediately after defibrillation in AF patients with isolated mitral valve disease. Electrical remodeling resulting from perpetuation of AF, pathological changes extending to the right atrium, geometric changes caused by the atrial interactions occurring across the interatrial septum, or a combination of these may explain the results.

Atrial Fibrillation↗

PubMed1999

A low-distortion filter method to reject muscle noise in multi-lead electrocardiogram systems.

This paper proposes a low-distortion filter method for rejection of muscle noise in multilead electrocardiogram (ECG) systems. This approach combines low-pass filtering with a modified version of source consistency filtering. The low-pass filtering splits the raw ECG signal into a muscle-noise-free part and a muscle-noise-overlapping part. The modified source consistency filtering then extracts the signal components from the muscle-noise-overlapping part. The extracted signal components are restored to the muscle-noise-free part as the output. The performance of our method was verified with simulated and clinically recorded ECG signals. The simulated ECG signals were created from computer simulation using three-dimensional, realistically shaped heart and torso models. The ideal signals are superimposed with white noise to simulate muscle noise and with a low frequency sine wave to simulate baseline drift. For verification, our method was compared with Butterworth low-pass filters. The results show that our method can effectively reduce muscle noise with less distortion of the QRS wave than conventional low-pass filters.

Artifacts↗

PubMed1998

Nuclear-recessive mutations of factors involved in mitochondrial translation are responsible for age-related respiration deficiency of human skin fibroblasts.

We addressed the question of whether both mitochondrial and cytoplasmic translation activities decreased simultaneously in human skin fibroblasts with the age of the donors and found that the age-related reduction was limited to mitochondrial translation. Then, to determine which genome, mitochondrial or nuclear, was responsible for this age-related, mitochondria-specific reduction, pure nuclear transfer was carried out from mitochondrial DNA (mtDNA)-less HeLa cells to four fibroblast lines, two from aged subjects, one from a fetus, and one from a patient with cardiomyopathy, and their nuclear hybrid clones were isolated. A normal fibroblast line from the fetus and a respiration-deficient fibroblast line from the patient were used as a positive and a negative control, respectively. Subsequently, the mitochondrial translation and respiration properties of the nuclear hybrid clones were compared. A negative control experiment showed that this procedure could be used to isolate even nuclear hybrids expressing overall mitochondrial respiration deficiency, whereas no respiration deficiencies were observed in any nuclear hybrids irrespective of whether their mtDNAs were exclusively derived from aged or fetal donors. These observations suggest that nuclear-recessive mutations of factors involved in mitochondrial translation but not mtDNA mutations are responsible for age-related respiration deficiency of human fibroblasts.

Aging↗

PubMed1998

Development of a non-invasive treatment system for urinary incontinence using a functional continuous magnetic stimulator (FCMS).

A system composed of a functional continuous magnetic stimulator (FCMS) and a saddle-type coil has been developed for non-invasive treatment of urinary incontinence, especially stress incontinence and urge incontinence. The FCMS conditions were as follows: 2 kW maximum electrical power consumption, 800 V maximum capacitor voltage, 720 microseconds pulsewidth (180 microseconds rise time), and 5-30 Hz frequency. A frequency between 5 and 10 Hz is used to treat urge incontinence and a frequency between 25 Hz and 30 Hz is used to treat stress incontinence. The coil (120 mm long, 90 mm wide and 50 mm thick) fits the most suitable region for this treatment, the region from the anus to the perineum. The coil is cooled to maintain a coil temperature between 20 and 25 degrees C so that it can be used efficiently and safely. In experiments with anaesthetised dogs, it was confirmed that the urethral pressure increased when the circumference of the perineum received continuous magnetic stimulation of 720 microseconds pulsewidth (180 microseconds rise time), 10 Hz frequency and about 520 V capacitor voltage. This result suggests that magnetic stimulation can be effective as a urinary incontinence therapy.

Animals↗