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Biomedical subjects

T Kondo

Publications and source records attributed to T Kondo.

At least 595 records · Page 33Linked to original sources
PubMed1997

Ultrasound biomicroscopic measurement of anterior chamber angle in premature infants.

AIM: To establish normative values for the anterior segment in premature infants in relation to postconceptional age and birth weight. METHODS: Anterior segments were measured in 39 premature infants, 25 to 39 weeks' gestational age by use of ultrasound biomicroscopy and a muscle hook with topical anaesthesia. RESULTS: Anterior chamber depth, trabecular-iris angle, angle opening (trabecular-iris) distances at 250 and 500 microns from the scleral spur, and the thickness of the thickest part of the iris showed linear increases in relation to postconceptional age and birth weight. CONCLUSIONS: Ultrasound biomicroscopy is a powerful tool for obtaining precise images and measurement of the anterior segment in preterm neonates. Normative values were established for anterior segment dimensions in relation to postconceptional age and birth weight.

Age Factors↗
PubMed1997

Brain tumors: detection with C-11 choline PET.

PURPOSE: To evaluate the effectiveness of positron emission tomography (PET) with carbon-11 choline in brain tumor imaging. MATERIALS AND METHODS: A rat glioma cell line (C6) was incubated with C-14 choline; the time course of uptake and metabolism was determined in vitro. C-11 choline was injected intravenously in tumor-bearing rats; the time course of distribution in organs was determined. C-11 choline also was injected intravenously in 20 patients (aged 6-86 years) with brain tumors and two volunteers (aged 38 and 58 years); distribution of the tracer in the brain was determined. Regional cerebral blood flow was measured by using oxygen-15 water on the same day. RESULTS: C-14 choline was metabolized to phosphoryl choline in glioma cells. The uptake of C-11 choline by glioblastoma cells was three to four times higher than that in the rat brain. All brain tumors took up more C-11 choline than did normal brain; thus, brain tumors that were not treated, as well as those that were treated with surgery or radiation therapy, were depicted. The tumor-normal brain uptake ratio of C-11 choline in brain tumor did not correlate with the O-15 water regional blood flow in the corresponding area. CONCLUSION: C-11 choline PET can depict brain tumors effectively. This method was clinically useful in patients who had undergone surgery.

Adult↗
PubMed1997

Distribution and neuropeptide content of nitric oxide synthase-containing nerve fibers in arteries and conduction system of the rat heart.

The rat heart receives its blood supply not only from the coronary arteries but also from the accessory coronary arteries that supply mainly the atria. The distribution and chemical nature of nitric oxide synthase-containing nerve fibers in the conduction system as well as the coronary and accessory coronary arteries were investigated using immunohistochemistry and NADPH diaphorase (NADPH-d) histochemistry. A few NADPH-d-positive nerve fibers were observed mainly around the main trunk of the coronary arteries, while NADPH-d-positive fibers were found along the entire course of the accessory coronary arteries from their main branches to the arteriolar level. A double-staining method demonstrated that NADPH-d-positive fibers innervating both the coronary and accessory coronary arteries contained vasoactive intestinal polypeptide or neuropeptide Y. NADPH-d-positive fibers were relatively abundant in the sinus node and penetrating bundle but were very sparse in the atrioventricular node and right bundle branch. No NADPH-d-positive fibers were detected in the left bundle branch. Some of the NADPH-d-positive fibers innervating the penetrating bundle exhibited distinct immunoreactivity to calcitonin gene-related peptide. These results suggest that nitric oxide may play a role as a neurotransmitter and/or neuromodulator in the neural control of the cardiac blood flow and impulse conduction.

Animals↗
PubMed1997

Rapid response to inhaled frusemide in severe acute asthma with hypercapnia.

We report 7 patients with severe acute asthma unresponsive to standard medication, including sympathomimetic agents, aminophylline and corticosteroids, who responded to inhaled frusemide. All were hypercapneic with a mean PaCO2 of 7.7 kPa (57.7 mm Hg) [range 6.2-8.8 kPa (46.2-66.3 mm Hg)]. Following nebulization of 20 mg frusemide, clinical response was rapid, and the mean PaCO2 fell significantly to 5.4 kPa (40.6 mm Hg) [range 5.0-6.2 kPa (37.5-46.5 mm Hg)] within 20-60 min. No adverse effect was recognized. Inhaled frusemide should be considered for treatment of acute asthma refractory to conventional therapy.

Acute Disease↗
PubMed1997

Overexpression of CuZn-superoxide dismutase reduces hippocampal injury after global ischemia in transgenic mice.

BACKGROUND AND PURPOSE: The role of copper, zinc-superoxide dismutase (CuZn-SOD) in hippocampal injury after transient global ischemia was studied using transgenic (Tg) mice and wild-type littermates. METHODS: Global ischemia was induced by bilateral common carotid artery occlusion. The hemisphere with the hypoplastic posterior communicating artery was determined and then the hippocampus in this hemisphere was evaluated qualitatively using a score of 0 to 4 and quantitatively using an image analyzer. RESULTS: Hippocampal injury was reduced in Tg mice after both 5 and 10 minutes of ischemia. In the 5-minute ischemia group, the mean score of the injury was significantly lower in Tg than nontransgenic (nTg) mice at 3 days. In the 10-minute group, the hippocampal injury was reduced more in Tg than nTg mice at 1 day. Quantitative evaluation by an image analyzer confirmed the qualitative data. Neurons with fragmented DNA were also studied in the hippocampal injury. In the 5-minute group, despite the reduction of the injury in Tg mice, their neurons with fragmented DNA were relatively increased at 1 day. In the 10-minute group, this ratio was almost the same in both nTg and Tg mice. CONCLUSIONS: CuZn-SOD plays a protective role in the pathogenesis of selective hippocampal injury after brief ischemia, whether the insult is relatively mild or intense. Furthermore, CuZn-SOD may reduce both necrotic and DNA fragmented neuronal death after global ischemia.

Animals↗
PubMed1997

Laser monitoring of chest wall displacement.

We developed a prototype laser monitor, consisting of a single laser sensor, to observe chest wall displacement during respiration. With this monitor, respiratory waveforms are expressed as an anterioposterior motion of the chest wall. The purpose of this study was to examine the characteristics and performance of this prototype. Performance was assessed: 1) under static conditions; 2) using a lung model ventilated in both conventional and high frequency oscillation (HFOV) modes; and 3) during spontaneous breathing in normal adults. In vitro, the monitor performed well both under static conditions and during mechanical ventilation. Reliable "respiratory" wave forms, with no frequency-dependent change in the relationship between displacement and volume, were produced during both conventional ventilation and HFOV at 15 Hz. In vivo, abdominal displacement, measured in the midline, was linearly correlated with the tidal volume signal integrated from flow. The waveforms produced by the monitor were adequate for monitoring respiration and for calculating respiratory timing variables. While a single laser sensor is unlikely to be sufficient for monitoring respiration in spontaneously breathing subjects, the performance of the prototype monitor was sufficiently impressive to encourage further development and further study of this type of truly noninvasive respiratory monitor.

Abdomen↗
PubMed1997

Mn SOD activity and protein in a patient with chromosome 6-linked autosomal recessive parkinsonism in comparison with Parkinson's disease and control.

We report Mn superoxide dismutase (SOD) protein and activity in a patient with familial autosomal recessive Lewy body-negative parkinsonism in comparison with patients with sporadic Parkinson's disease (PD) and controls. We recently proved linkage of this family with markers of chromosome 6 at 6q25.2-27, which included the Mn SOD gene. We used a novel polymorphic mutation at -9 position of the signal peptide of the Mn SOD precursor protein, which caused valine to alanine substitution. All the affected members of this family showed homozygosity for alanine, whereas nonaffected members, sporadic PD patients, and the control subjects studied showed either heterozygosity of alanine and valine or homozygosity of valine. The Mn SOD activity of this familial patient was the highest among the PD patients and the control subjects studied, and an abundant expression of Mn SOD was found in the substantia nigra. The molecular weight of Mn SOD protein by Western blotting of this patient was essentially similar to that of PD patients and the control subjects. High Mn SOD activity may constitute a genetic risk factor in this familial patient. The difference in the signal peptide sequence may affect the expression of Mn SOD within mitochondria; however, it is unlikely that loss of function type Mn SOD mutation is the cause of this familial parkinsonism. Mn SOD in sporadic PD patients was similar to that in controls.

Adult↗
PubMed1997

Effect of karasurin-A on nitric oxide production by murine macrophages and mitogenic response of murine splenocytes in vitro.

We studied the effect of karasurin-A, a type-I ribosome-inactivating protein (RIP) isolated from fresh root tubers of Trichosanches kirilowii MAX. var. japonica KITAMURA, on the mitogenic response of murine splenocytes and nitric oxide (NO) production by murine peritoneal macrophages in vitro. Karasurin-A inhibited the lymphocyte proliferation by LPS, ConA and PHA and NO production by LPS at non-cytotoxic concentrations (10-1000 ng/ml for splenocytes and 10-100 ng/ml for macrophages, respectively). These data suggest that karasurin-A has immunosuppressive activity in vitro.

Animals↗
PubMed1997

Cloning and bacterial expression of a gene encoding ribosome-inactivating proteins, karasurin-A and karasurin-C, from Trichosanthes kirilowii var. japonica.

A genomic DNA clone of karasurin was isolated using the polymerase chain reaction from Trichosanthes kirilowii var. japonica (Cucurbitaceae). The amino acid sequence deduced from the nucleotide sequence was consistent with previously reported sequences of karasurin-A and karasurin-C except for a putative signal peptide and extra amino acids at the C-terminus, neither of which is present in the natural protein. Recombinant karasurin was synthesized in Escherichia coli, in which the cloned karasurin gene was expressed under the control of the trc promoter.

Amino Acid Sequence↗
PubMed1997

Novel histamine H3 receptor antagonists: synthesis and evaluation of formamidine and S-methylisothiourea derivatives.

In order to obtain a new, potent and selective histamine H3 receptor antagonists, chemical modifications of thioperamide, a well-known H3 receptor antagonist, were conducted. A new series of compounds has been synthesized by modifying the thiourea and cyclohexyl groups of thioperamide, and tested for H3 affinity by receptor binding assay using plasma membrane from rat cerebral cortex. The thiourea group of thioperamide was found to be replaceable with a basic moiety such as formamidine or S-methylisothiourea. Replacement of the cyclohexyl group in thioperamide by a 1-adamantyl or an exo-2-norbornyl group increased the affinity for H3 receptor. Among the compounds synthesized, N-(1-adamantyl)-N',N'-[3-(4(5)-1H-imidazolyl)pentamethylene] formamidine 3f (AQ0145) showed the highest H3 receptor affinity, having a potent antagonistic activity. This compound was at least 1,000-fold more active towards H3 than towards H1 and H2 receptors.

Amidines↗
PubMed1997

Effects of dietary pyrazinamide on the metabolism of tryptophan to niacin in streptozotocin-diabetic rats.

We investigated the effects of feeding with a diet containing pyrazinamide (PYR) on the metabolism of L-tryptophan (Trp) to nicotinamide in streptozotocin (STZ)-diabetic rats and whether the diabetic action of STZ is prevented by feeding with the PYR diet, which is known as an inhibitor of aminocarboxymuconate-semialdehyde decarboxylase and poly(ADP)ribose synthetase and therefore, significantly increases the formation of nicotinamide from Trp in normal rats. As was expected, feeding with the PYR diet to the STZ-injected rats caused a significantly increased excretion of nicotinamide and its metabolites like that in normal rats. The body weight increased in the STZ-injected rats fed with the PYR diet, while it was lost in the STZ-injected rats fed with the non-PYR diet. However, the blood glucose level and the urinary excretion of glucose were not improved even when the rats were fed with the PYR diet. Therefore, it was suggested that chronically increasing the formation of nicotinamide from Trp could not completely prevent the STZ-diabetic action.

Animals↗
PubMed1997

Measurements of PEEP-induced changes in lung volume: evaluation of a laser monitor.

STUDY OBJECTIVE: To evaluate a newly developed laser monitor in the measurement of positive end-expiratory pressure (PEEP)-induced changes in end-expiratory lung volume (EELV) in spontaneously breathing subjects. DESIGN: An open comparison between two different methods to assess breathing parameters. SETTING: A respiratory research unit. PARTICIPANTS: Six spontaneously breathing, healthy volunteers. INTERVENTIONS: Stepwise increases of PEEP from 0 to 0.8 to 1.6 kPa during spontaneous breathing; repeated validation of the laser monitor in each subject. MEASUREMENTS AND RESULTS: Pressure and flow were recorded at the airway opening. Abdominal wall displacement (AWD) measured by the laser sensor was recorded simultaneously. The time lag between the volume and the laser signals during baseline was 0.068+/-0.052 s and during maximal PEEP, 0.108+/-0.093 s. There was no baseline drift in either the PEEP or the AWD signals. Mean EELV decreased by 290 mL to 1,157 mL after the PEEP valve was removed. Within each individual, the ratio between EELV and AWD showed only small variations. Measurements of tidal volume (VT) and AWD showed good agreement at all PEEP levels. Mean VT decreased in all but one subject during PEEP. With the increase in PEEP, the end-expiratory abdominal baseline increased linearly over a large range of end-expiratory pressures with a flattening of the curve at high PEEP levels in all subjects. CONCLUSIONS: The laser monitor is sufficiently accurate for measuring PEEP-induced changes in EELV during spontaneous breathing in healthy adult subjects. Monitors incorporating multiple laser sensors may have considerable clinical promise.

Adult↗
PubMed1997

Yeast functional assay of the p53 gene status in human cell lines maintained in our laboratory.

We used a yeast functional assay (functional analysis of separated alleles in yeast: FASAY) to determine the p53 gene status of human cell lines maintained in our laboratory. This assay enables the researcher to score wild-type p53 expression on the basis of the ability of expressed p53 to transactivate the reporter gene HIS 3 via the p53-responsive GAL 1 promoter in Saccharomyces cerevisiae. The cell lines examined were ten hepatoma, two hepatoblastoma, three in vitro immortalized fibroblast, two osteosarcoma, a chondrosarcoma, an ovarian teratocarcinoma and a colon cancer cell line. Out of 20 cell lines, 11 cell lines had mutations in both alleles of the p53 gene, and another 8 cell lines had no mutation in the p53 gene. Thus, 55% of the cell lines examined had mutations in the p53. Interestingly, PA-1 cells had both the normal and the mutant p53 alleles, showing that FASAY is a useful method for detecting the wild-type and mutated p53 genes simultaneously. As for the three liver cell lines harboring HBsAg, there was no relationship between their p53 gene status and the presence of HBsAg. Two cell lines were normal for p53 status, while the other had a mutation of the p53 gene.

Alleles↗
PubMed1997

Mortality associated with selegiline in Parkinson's disease. What do the available data mean?

A recent study by the Parkinson's Disease Research Group of the United Kingdom revealed higher mortality in patients with Parkinson's disease who were treated with selegiline (deprenyl) compared with those who were not. In this article, the methodological limitations of the UK study are discussed. Although several problems exist with this study, the mortality rate was correct, since the data were obtained from a verifiable source. The question then is whether or not the higher mortality rate can be ascribed to selegiline. It is difficult to find answers to this question in the study data, and we will have to wait for the study authors' final report. No other studies have reported higher mortality with selegiline. However, when prescribing selegiline in patients with early-stage Parkinson's disease, it is important to provide them with all the available information so that treatment decisions can be made jointly. Meanwhile, the best indication for selegiline appears to be motor fluctuations in patients with moderately advanced Parkinson's disease.

Antiparkinson Agents↗
PubMed1997

The mechanism of respiratory rhythm generation during constant flow assisted mechanical ventilation in the decerebrated dog.

In awake human subjects input from the forebrain has significant effects on the respiratory pattern during assisted (AMV) and controlled (CMV) mechanical ventilation. The hypothesis in this animal study was that if the influence from the forebrain is eliminated, the respiration during AMV and that during CMV is controlled by the same mechanism. Fifteen decerebrated and tracheostomized dogs were subjected to CMV with a variety of combinations of tidal volume and frequency. The respiratory rhythm during CMV was simulated by a mathematical model composed of the central respiratory activity and inputs from pulmonary receptors. During AMV, the respiratory cycle duration was prolonged, and this was found to be the summated effect of prolonged Ttg (ventilator trigger period) and shortened Tinf (lung inflation period). When these changes in Ttg and Tinf were included, the model for CMV predicted respiratory changes during AMV. We concluded that the basic mechanism controlling AMV and CMV may be the same.

Animals↗
PubMed1997

Total anomalous pulmonary vein drainage in an adult diagnosed by helical computed tomography.

A 41-year-old man visited our hospital with the complaint of palpitation by atrial flutter. He was finally diagnosed as total anomalous pulmonary vein drainage by helical computed tomography (CT). This case is very unusual due to the lack of symptoms until the age of 41. The absence of pulmonary artery stenosis, and the presence of atrial septal defect providing sufficient right to left shunt flow to maintain the output of left ventricle are some of the reasons to explain the lack of symptoms and very slight impact on daily life. Helical CT, in particular 3-dimensional imaging, is very useful in diagnosing complicated cardiovascular deformation as in this case.

Adult↗
PubMed1997

Rapid reduction in ryanodine binding of hippocampus CA1 in cerebral ischemia.

Ryanodine receptors located on the sarcoplasmic or endoplasmic reticulum, play an important role in the regulation of the intracellular Ca2+ level via the mechanism of Ca(2+)-induced Ca2+ release (CICR). Perturbation of intracellular Ca2+ regulation has been considered to be one of the most important mechanisms underlying acute ischemic neuronal damage. The ryanodine binding, an indicator of intracellular channels of CICR, and local cerebral blood flow (LCBF) were therefore examined at 15 min post-ischemia in the gerbil brain. The autoradiographic method developed in our laboratory enabled us to determine both parameters within the same brain. Severe hemispheric cerebral ischemia was induced by occluding the right common carotid artery. LCBF was measured at the end of the experiment using [14C]iodoantipyrine method. The ryanodine binding was evaluated autoradiographically in vitro using [3H] ryanodine. A group of gerbils who underwent a sham procedure served as controls. LCBF was found to be significantly decreased in most cerebral regions on the occluded side. In contrast, a significant reduction in ryanodine binding was noted only in the hippocampus CA1 on the occluded side. Taken together, these findings indicate that the CICR in the hippocampus CA1 may be especially susceptible to acute ischemic stress, and be closely associated with the pathophysiological mechanisms of the selective vulnerability of this region.

Animals↗