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Biomedical subjects

S Kitamura

Publications and source records attributed to S Kitamura.

At least 613 records · Page 34Linked to original sources
PubMed1992

[A case of motor neuron disease with dementia--cerebral blood flow and cerebral oxygen metabolism].

A 51-year-old man developed muscle weakness of the bilateral upper extremities, and mental changes beginning with personality change. There was no history of mental illness in his family. A neurological examination 1 year after the onset revealed muscle atrophy and fasciculation of his bilateral upper extremities Neuropsychological examination revealed concrete speech, paraphasia, and lack of judgment. Disorientation, amnesia, dyscalculia, and spatial agnosia, however, were not recognized. These neuropsychological findings were compatible with dementia of frontal lobe type. EMG and muscle biopsy revealed neurogenic muscular atrophy. There was no abnormal findings in the brain X-CT and the brain MRI. PET study using C15O2 and 15O2 revealed reduction of cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) in the bilateral medial frontal cortex, the left temporal cortex and the bilateral thalamus. From these these findings the patient was diagnosed as having motor neuron disease with dementia. Muscle atrophy and dementia worsened gradually. A second PET study 2 years and 6 months after the onset revealed severe reduction of CBF and CMRO2 in the bilateral temporal cortex and the thalamus. These PET findings suggested that dysfunction of the temporal cortex and the thalamus related to dementia in this case.

Brain↗
PubMed1992

[A case of anaplastic carcinoma of the mediastinal goiter].

We reported a case of anaplastic carcinoma of mediastinal goiter. The initial symptom was hoarseness, and thyroid scintigram and venogram revealed mediastinal thyroid malignant tumor, although cervical tumor could not be palpated. Operation was performed with median sternotomy. The size of the tumor was 8 x 6 x 3cm. Histological examination showed papillary adenocarcinoma of left lower pole of the thyroid gland which was transformed into anaplastic carcinoma and extended to the mediastinal cavity. Anaplastic carcinoma of mediastinal goiter is very rare, and our case showed anaplastic transformation from papillary adenocarcinoma.

Adenocarcinoma, Papillary↗
PubMed1991

Synaptic connections of a low-threshold mechanoreceptive primary neuron within the trigeminal subnucleus oralis.

The central axon of a primary afferent neuron that responded to indentation of the glabrous skin of the lower lip in a slowly adapting fashion was intra-axonally injected with horseradish peroxidase. The labeled terminal within the subnucleus oralis was examined electron microscopically. The labeled ending had a pale axoplasm and contained clear spherical synaptic vesicles. The labeled ending formed a synaptic triad with a dendrite and an unlabeled axonal ending with pleomorphic vesicles (a mixture of oval, flattened and dense core vesicles). The labeled primary ending was presynaptic only to the dendrite, while the unlabeled ending was presynaptic to both the dendrite and the labeled primary ending.

Animals↗
PubMed1991

A differential scanning calorimetric study of the thermal unfolding of seven mutant forms of phage T4 lysozyme.

High-sensitivity differential scanning calorimetry has been applied to the study of the reversible thermal unfolding of the lysozyme of T4 bacteriophage in which the threonine residue at position 157 has been replaced by seven different residues. High-resolution structures derived from X-ray crystallography have been reported for these and six other mutants by Alber et al. [Alber, T., Dao-Pin, S., Wilson, K., Wozniak, J. A., Cook, S. P., & Matthews, B. W. (1987) Nature 330, 41-46]. At pH 2.5 the changes relative to the wild-type protein in the standard free energy of unfolding produced by these mutations indicate apparent destabilizations of 0.6 kcal mol-1 (T157R) to 1.9 kcal mol-1 (T157I), whereas the changes in enthalpy of unfolding range from -5.8 kcal mol-1 (T157N) to 11.9 kcal mol-1 (T157E). Since the denaturations are in all cases accompanied by large changes in heat capacity amounting to 2.5 kcal K-1 mol-1, both the free energies and enthalpies are functions of temperature. An intriguing feature of the present results is the relatively large enthalpy changes and the corresponding compensating entropy changes. Our present understanding of the intramolecular energetics of proteins is insufficient to account for these changes.

Calorimetry, Differential Scanning↗
PubMed1991

Location of the motoneurons supplying the rabbit pharyngeal constrictor muscles and the peripheral course of their axons: a study using the retrograde HRP or fluorescent labeling technique.

The location of the motoneurons supplying the rabbit pharyngeal constrictor muscles (the superior and the middle constrictors, and the thyropharyngeus and the cricopharyngeus; the last two collectively compose the inferior constrictor) was investigated with intramuscular injection of HRP or the fluorescent tracer nuclear yellow into the individual muscles. Moreover, the peripheral course of their axons was investigated by injection of HRP into all of the pharyngeal constrictors in conjunction with intracranial severing of either the vagus or the glossopharyngeal nerves. The pharyngeal constrictor motoneurons were ipsilaterally located within a subdivision of the nucleus ambiguus which is formed by a compact arrangement of the smallest neurons of the nucleus and situated in the rostral half of the nucleus. We named that subdivision the compact cell group (CoG). Axons of the pharyngeal constrictor motoneurons traversed the vagal rootlets. The rostrocaudal extent of the pharyngeal constrictor motoneurons covered almost the entire length of CoG at a level from about 500 to 2,900 microns rostral to the obex, with their number being most numerous in the middle one-third level of the CoG. Although the motoneurons of the superior constrictor, those of the middle constrictor, and those of the thyropharyngeous and the cricopharyngeus overlapped considerably in location, they tended to be arranged rostrocaudally in that order. At the middle one-third level of the CoG, where the CoG is subdivided into dorsomedial and ventrolateral subgroups of neurons, the superior and the middle constrictor motoneurons were confined to the medial portion of the dorsomedial subgroup, while the inferior constrictor motoneurons were distributed throughout its entirety.

Animals↗
PubMed1991

Thermally induced conformational transition of double-stranded xanthan in aqueous salt solutions.

The thermally induced conformational transition of double-stranded xanthans (degree of pyruvate substitution, DSp = 0.45) having Mw = 3.1, 5.7, and 20.3 x 10(5) has been studied in aqueous salt solutions by high-sensitivity differential scanning calorimetry (DSC). The double strandedness of these samples in the ordered conformation was ascertained by the value of mass per unit length, ML = 2090 +/- 270 g mol-1 nm-1, which was determined from the contour length obtained by electron microscopic observations and the molecular weight by light scattering measurements. The temperature at half completion of the transition T 1/2 for these samples increased linearly with the logarithm of the cation (Na+, K+) concentration. The plot of 1/T1/2 vs the natural logarithm of cation (Na+) concentration in mM for the sample with Mw = 5.7 x 10(5) (15-SX) yielded the equation 10(3)/T1/2 = 3.45-0.159 ln [Na+]. The specific enthalpy delta hcal for 15-SX, essentially independent of salt concentration above 20 mM, was 8.31 +/- 0.39 J/g (SD, n = 6). No systematic dependence of molecular weight on the transition temperature and the enthalpy was observed. Application of the Manning polyelectrolyte theory to the system using the DSC data suggested that the separation of the double strand of xanthan into two single chains was not completed at the temperature where the endothermic peak was finished. This suggestion is consistent with recent findings by light scattering measurements as a function of temperature. Our DSC study was extended to include four other samples from various sources. It was found that T1/2 and delta hcal depend on the pyruvate contents of the samples. For example, the t1/2 (t1/2/degrees C = T1/2/K - 237.15) values for samples with high pyruvate content (DSp = 0.9) and depyruvated (DSp = 0.14) in 20 mM aqueous NaCl were 48.8 and 85.3 degrees C, respectively. Two other samples showed relatively broad DSC curves having shoulders, which were resolved into two independent components. Thermodynamic parameters for each component were examined as a function of salt concentration, and the results obtained were interpreted in terms of the heterogeneity of the pyruvate content of the samples.

Calorimetry, Differential Scanning↗
PubMed1991

X-ray structural studies and physicochemical characterization of (E)-6-(3,4-dimethoxyphenyl)-1-ethyl-4-mesitylimino-3-methyl- 3,4-dihydro-2(1H)-pyrimidinone polymorphs.

The polymorphism of (E)-6-(3,4-dimethoxyphenyl)-1-ethyl-4-mesitylimino-3-methyl-3,4-di hydro- 2(1 H)-pyrimidinone (FK664; 1) was characterized by using X-ray powder diffractometry, differential scanning calorimetry (DSC), and IR spectroscopy. Structures of two polymorphs (Forms A and B) were determined by X-ray crystallographic analysis. Form A crystallized in the monoclinic space group P2(1)/c, with a = 13.504(2), b = 6.733(1), c = 24.910(8) A, beta = 96.55(4) degrees, z = 4, and dcal = 1.203 g/cm3, while Form B crystallized in the same space group, with a = 8.067(2), b = 15.128(4), c = 18.657(4) A, beta = 102.34(3) degrees, z = 4, and dcal = 1.216 g/cm3. The conformational features of 1 were very similar between the two polymorphs. Compound 1, in both crystal forms, took an energetically reasonable conformation in three rigid planes, such as 2-pyrimidone, trimethylphenyl, and dimethoxyphenyl rings, but the molecules were packed in different ways between the two polymorphs. In the Form B crystal, a short contact was possible, to form pi-pi interactions between two dimethoxyphenyl groups related with the inversion center in the crystal lattice; this interaction seems to contribute to stabilizing the crystal structure of Form B. Both Forms A and B showed only one endothermic peak due to fusion at 115 and 140 degrees C, respectively, on the DSC thermograms; therefore, it is suggested that there are no transition points between the two polymorphs. The heats of fusion obtained from the DSC thermograms were 33.2(2) kJ/mol for Form A and 36.8(1) kJ/mol for Form B.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemical Phenomena↗
PubMed1991

Dissection of the cardinal ligament in radical hysterectomy for cervical cancer with emphasis on the lateral ligament.

Surgical experience with carcinomas of the uterus and rectum has provided new insights into the surgical anatomy of a lamina, which separates the paravesical space from the pararectal space. It has been proved that each of the lamina consists of the cardinal and lateral ligaments and pelvic splanchnic nerves, descending in the following order. The cardinal and lateral ligaments, as a connective stalk, insert into the lateral walls of the uterus and rectum extending from the inner aspect of the pelvic wall. Clarification of this structural relationship led to the development of a new procedure for the dissection of the cardinal ligament in radical hysterectomy, while still preserving the lateral ligament. This facilitated systematic dissection of the cardinal and uterosacral ligaments with posterior manipulation, leading to a reduction in blood loss and to prevention of brisk bleeding from the venous plexuses.

Dissection↗
PubMed1991

Effects of trimetaphan on the cardiovascular response to tracheal intubation.

In three groups of 10 patients, we have studied the effect on the cardiovascular responses to laryngoscopy and intubation of bolus doses of saline or trimetaphan 0.05 mg kg-1 or 0.1 mg kg-1 given 1.75 min before the start of laryngoscopy. Anaesthesia was induced with thiopentone 5 mg kg-1 i.v. and tracheal intubation was facilitated with vecuronium 0.2 mg kg-1. During anaesthesia, ventilation was assisted or controlled with 1% enflurane and 50% nitrous oxide in oxygen. Patients receiving saline showed a significant increase in mean arterial pressure and rate-pressure product associated with tracheal intubation. These increases following tracheal intubation were less in trimetaphan-treated patients compared with those of the control group (P less than 0.05). There was no significant difference in heart rate following tracheal intubation between the three groups. These data suggest that trimetaphan may be used as a supplement during induction, to attenuate the hypertensive response associated with laryngoscopy and tracheal intubation.

Anesthesia, General↗
PubMed1991

Hemodynamics and coronary blood flow during exercise after coronary artery bypass grafting with internal mammary arteries in children with Kawasaki disease.

BACKGROUND: Saphenous vein grafts (SVG) and internal mammary artery (IMA) grafts have been used for coronary artery bypass grafting. In adult patients with bypass grafting for atherosclerotic coronary artery disease, IMA grafts have been reported to have long-term patency; however, results are conflicting on whether the graft is sufficient to meet increased myocardial oxygen demand during exercise. There have been no studies on hemodynamics and blood flow during exercise after bypass grafting with IMA in pediatric patients with Kawasaki disease. METHODS AND RESULTS: We studied 17 pediatric patients with Kawasaki disease (average age, 7.5 +/- 3.1 years), who underwent coronary artery bypass grafting with the IMA. The average number of coronary artery bypass grafts was 2.1 +/- 0.7/patient. For all patients, the left IMA was anastomosed to the left anterior descending coronary artery; for eight patients, the right IMA was also anastomosed to the right coronary artery. In addition, 11 SVGs were used. The postoperative patency rates after 1 month were 100% with the IMA graft and 91% with SVG. One year after the operation, the patency rates were 100% with IMA and 50% with SVG. Hemodynamics during exercise were measured with a bicycle ergometer, and coronary sinus blood flow was measured by the continuous thermodilution method in six patients. The relation between delta LVEDP (the difference between left ventricular end-diastolic pressure at rest and during exercise) and delta SVI (the difference between the stroke volume index at rest and during exercise) was analyzed. Four of six patients had reduced cardiac function before operation (delta LVEDP, positive; delta SVI, negative). However, after the operation, all patients demonstrated improvements in cardiac function during exercise (delta LVEDP, positive; delta SVI, positive). Coronary sinus flow per left ventricular mass increased after operation from 70 +/- 46 to 87 +/- 56 ml/min at rest (p less than 0.05) and from 139 +/- 118 to 183 +/- 150 ml/min during exercise (p less than 0.05). CONCLUSIONS: In conclusion, this study reveals improvements in both hemodynamics and coronary blood flow during exercise after coronary artery bypass grafting with IMA grafts in pediatric patients with Kawasaki disease.

Adolescent↗
PubMed1991

[Hyperperfusion syndrome following bilateral aorto-carotid bypass--a study of transcranial Doppler].

A 22-year old female with Takayasu disease, who underwent bilateral aorto-carotid bypass surgery developed hyperperfusion syndrome postoperatively. Following the operation, convulsion and headache developed and mean velocity in the middle cerebral artery, measured by transcranial doppler, elevated. Mean velocity gradually decreased on the 10th postoperatively day and became a plateau at 200% of preoperative value. Pulsatility index as a index of cerebral vascular resistance was low just after the operation, became normal the following day and gradually increased 10 days after the operation. These changes seem to be recovery of cerebral autoregulation. On the 20th postoperative day, computed tomography scan was examined and multiple low density areas were found in the basal ganglia regions, but these changes disappeared 2 months after the operation. These reversible changes of CT scan might show ischemic changes or cerebral edema induced by cerebral vasospasm.

Adult↗
PubMed1991

[Perioperative monitoring of cerebral circulation in a patient with Takayasu disease].

Transcranial Doppler (TCD) and fiberoptic oximetry for continuous measurement of jugular venous oxygen saturation (SjO2) were used as perioperative monitoring of cerebral circulation in a patient with Takayasu disease who received bilateral aorto-carotid bypass. Following revascularization of the left carotid artery, mean velocity in the middle cerebral artery (MV) increased (lt 300%, rt 200% of control values) and SjO2 also increased. Following revascularization of right carotid artery, MV increased (lt 500%, rt 400% of control values) but SjO2 was unchanged. After bilateral revascularization, high velocity continued for about 10 days, and convulsion with headache occurred. Therefore hyperperfusion syndrome was suspected. By perioperative monitoring of MV and SjO2, it might be possible to evaluate intracranial hemodynamics, necessity of shunt operation as well as bilateral bypass, and postoperative hyperperfusion syndrome.

Adult↗
PubMed1991

[A case of prolonged eosinophilic pneumonia with pulmonary emphysema and bronchial asthma diagnosed by open lung biopsy].

A 65-year-old man was admitted to our hospital complaining of productive cough, dyspnea and stridor. Chest X-ray disclosed overinflation with micronodular infiltrates. Blood examination showed mild eosinophilia and IgE elevation. Pulmonary function test disclosed severe airway obstruction and diffusion capacity impairment. Although clinical improvement was achieved after bronchodilator therapy, laboratory abnormalities continued. Open lung biopsy demonstrated mononuclear cellular and eosinophilic infiltration at alveolar lumen and vessel walls without prominent fibrosis, which was compatible for prolonged eosinophilic pneumonia. From above findings, this case was thought as a prolonged eosinophilic pneumonia combined with pulmonary emphysema and bronchial asthma.

Aged↗
PubMed1991

Relationship between blood pressure and left ventricular mass in male patients with essential hypertension.

We performed retrospective study of the relationship between the severity and duration of hypertension and echocardiographically-detected left ventricular hypertrophy (echo-LVH) in patients with untreated essential hypertension. The subjects consisted of 92 untreated essential hypertensives who were observed for more than 5 years from the onset of diastolic hypertension (greater than or equal to 95 mmHg), and whose left ventricular (LV) mass index was measured at the end of the observation period. On the basis of the frequency of diastolic hypertension during the observation period, the population was categorized in 3 groups. In Group I (32 cases), diastolic hypertension was observed in more than 80% of blood pressures obtained throughout the entire observation period. In Group II (38 cases), diastolic hypertension was observed in 33 to 80% of the observation period. In Group III (22 cases), diastolic hypertension was observed in less than 33% of the observation period. The average diastolic blood pressure during the entire observation period in each group were 101.0, 96.0, and 90.7 mmHg in groups I, II, and III, respectively. The LV mass index was significantly higher in groups I (114.6 g/m2) and II (105.3 g/m2) than in group III (90.7 g/m2) (p less than 0.01). The prevalence of echo-LVH (more than 121 g/m2) was 34.4%, 18.4%, and 4.8% in groups I, II, and III, respectively. The average diastolic blood pressure in patients with echo-LVH (99.3 +/- 5.1 mmHg) was significantly higher than in patients without echo-LVH (95.7 +/- 4.7 mmHg). We concluded that the degree and duration of diastolic pressure elevation are closely correlated to the LV mass index.

Blood Pressure↗
PubMed1991

[The metabolism of peptide leukotrienes in the lung may affect their coronary vasoconstrictive effect in anesthetized dogs].

The deteriorative effect of peptide leukotrienes (LTs) on the coronary circulation are well known. On the other hand, it has been recognized that some of these prostanoids are metabolized in the pulmonary vascular bed. To clarify the influence of the metabolism of LTs in the lung on their effects to the coronary circulation, we compared the changes of coronary circulation parameters by leukotriene D4 (LTD4) and C4 (LTC4) administered (5 mcg/kg) into the right atrium (RA) and the left atrium (LA) in 8 mongrel dogs. After the administration of LTD4 and LTC4, significant reduction of coronary blood flow (LTD4-RA 65.8 +/- 3.4%, LTD4-LA 54.8 +/- 2.3%, LTC4-RA 64.3 +/- 3.9%, LTC4-LA 66.9 +/- 3.7%) and elevation of coronary vascular resistance (LTD4-RA 130.5 +/- 8.2%, LTD4-LA 157.3 +/- 6.1%, LTC4-RA 138.7 +/- 8.0%, LTC4-LA 129.5 +/- 10.1%) were recognized. The effect of LTD4, administered into the left atrium was significantly greater than that administered into the right atrium (p less than 0.05). The difference between right and left atrial administration was not statistically significant, although a tendency for the effect to be greater with right atrial administration than left was recognized. The LTC4 concentration in aortic blood measured by radioimmunoassay was significantly lower in right atrial administration than left (p less than 0.05). These results suggested that LTD4 was metabolized and inactivated in the lung during its passage through the pulmonary circulation, and LTC4 was not only inactivated but also converted to LTD4 and activated in the pulmonary vascular bed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[A new criterion for hCG administration in human IVF programs: importance of serum LH levels].

A new, simple criterion for hCG administration to induce ovulation for IVF is described. Serum LH levels were measured daily, and hCG was administered, independent of follicle size or estradiol levels, the night of the day when the LH level first exceeded the J level, defined as the minimum value + (the day 3 value-the minimum value) x 1/3. Based on this hCG criterion, the total and ongoing pregnancy percentages per cycle were 35% and 27%, respectively. It appears that the pregnancy rate decreases when hCG is administered one day before or one day after the criterion is met. Pregnancies resulting from hCG administration based on the criterion had a wide range both of dominant follicle diameter (14-21 mm) and estradiol level (229-2,050 pg/ml). The serum LH level is recommended as a useful parameter in timing hCG administration for IVF.

Chorionic Gonadotropin↗