Search PubMed⌕ Search

Biomedical subjects

S Kitazawa

Publications and source records attributed to S Kitazawa.

At least 91 records · Page 5Linked to original sources
PubMed1995

Effect of the angiotensin-converting enzyme inhibitor alacepril on ventricular function and beta-adrenoceptor number in rabbits with aortic regurgitation.

This study was performed to determine the effects of the angiotensin-converting enzyme inhibitor alacepril on hemodynamic variables and beta-adrenoceptor number in rabbits with heart failure induced by aortic regurgitation. Aortic regurgitation was induced by perforation of the aortic valve in 12 rabbits. Sixty mg/kg of alacepril was administered by gastric tube for 7 days after manifestation of aortic regurgitation to 6 rabbits (group AR + A). The other 6 rabbits with aortic regurgitation were administered vehicle in the same fashion (group AR + C). Seven rabbits underwent sham operation (group S). One week after induction of aortic regurgitation left ventricular end-diastolic pressure was higher and cardiac output was lower in AR + C than in S. End-diastolic and end-systolic left ventricular diameter were larger and left ventricular weight was also higher in AR + C than in S. For each of these parameters, the opposite findings were obtained from a comparison of AR + A and S. Myocardial beta-adrenoceptor density and norepinephrine content were reduced in AR + C, but were restored in AR + A. These findings indicate that alacepril has beneficial effects on ventricular remodeling and function, and on sympatho-neuronal regulation in the volume-overloaded myocardium.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

Effects of delayed visual information on the rate and amount of prism adaptation in the human.

Accurate reaching towards a visual target is initially disturbed when the visual field is displaced by prisms, but recovers with successive trials. To determine how the improvement depends on the visual error signals associated with the motor output, the time course of prism adaptation was studied with delayed visual information on the error. Subjects were trained to reach rapidly at a target on a tangent screen. Vision was always blocked during the movement, and allowed again only after the index finger touched the screen. One experiment consisted of three sets of 30 trials. In the first set, the subject wore no prisms and vision was allowed without delay. In the second, the visual field was displaced by prisms, and vision was available only after a delay period of 0-10,000 msec while the subjects maintained their final pointing position. Initially, the subject misreached the target by about the amount of visual displacement (60 mm). Errors decreased with trials by an amount proportional to the error in the preceding trial. The rate of decrease of error was generally largest when the delay was 0 msec, became significantly smaller when the delay was 50 msec, and showed only gradual change with longer delays. In the third set, the subject wore no prisms and vision was allowed without delay. Initial misreaching in the direction opposite to the visual displacement, reflecting the amount of adaptation in the second set, was generally largest with no delay (median of 46 mm) and significantly smaller with 50 msec and longer delays (17-33 mm).(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1995

Development of skeletal metastases.

Skeletal metastases result from a series of complex steps including activation of osteoclasts and interaction between adhesion molecules on cancer cells and bone matrices. Researchers of this study used pathologic specimens of breast cancer cells from primary and metastatic sites obtained at surgery or autopsy to demonstrate the expression of parathyroid hormone-related protein by immunohistochemistry and beta 3 integrin by in situ hybridization to clarify the role of tumor-derived osteoclast activating factors and adhesion molecules in the development of skeletal metastases. The results of this retrospective study showed a significant difference of parathyroid hormone-related protein and beta 3 integrin expression in cases with and without skeletal metastases. These expressions were enhanced or clonally selected or both in skeletal metastatic sites. Because activation of osteoclastic bone resorption by parathyroid hormone-related protein could facilitate tumor cells to attach to the eroded bone surface through cell adhesion molecules, these 2 factors could make it easier for tumor cells to grow in bone.

Adult↗
PubMed1995

[Sex-related differences in EEG coherence in normal young adults--evaluation during rest and photic stimulation].

EEG coherence is a noninvasive technique for studying functional relationships between brain regions. Although EEG coherence would be a useful method to explore the differences in cerebral functional organization between the sexes, sex differences in coherence have not been well documented. The present study was conducted therefore to examine sex differences in interhemispheric EEG coherence during rest and photic stimulation (PS) in 15 male and 15 female healthy young adults. Interhemispheric coherence of the resting EEG revealed no significant sex differences for any frequency band. In contrast, coherence during PS revealed significant sex differences, and the females had a significantly higher coherence than the males in the frequency band (4.5-5.5Hz) corresponding to 5Hz PS. In addition, the changes in interhemispheric coherence from rest to the stimulus condition (i.e., coherence reactivity) showed sex differences at the brain region primarily involved in visual functioning; the females had significantly greater coherence reactivity for O1-O2 in EEG during PS at 5 and 15Hz. These findings indicate sex differences in interhemispheric EEG coherence during PS, and provide further evidence that sex-related differences exist in the degree of lateralization of hemispheric function.

Adult↗
PubMed1995

[Ethosuximide].

Explore the source record for details and available documents.

Adult↗
PubMed1995

DNA resynthesis and binucleated metamorphosis in cardiac muscle cells after isoproterenol-induced injury: bromodeoxyuridine immunohistochemistry.

In this study, we assessed reactive DNA synthesis in mouse cardiac myocytes after injury in vivo using the Bromodeoxyuridine (BrdU) immunohistochemical method and clarified binucleated metamorphosis of S-phase cardiac myocytes in the myocardial healing process. The animals were injured by isoproterenol i.p., and studied 0, 1, 2, 3, 5 and 10 days after injury. Each animal was killed 3 hr after labeling with BrdU i.p. The BrdU labeling index was calculated 0, 1, 2, 3, 5 and 10 days after injury. Moreover, we observed the morphological difference of S-phase cardiac myocytes between Group A and Group B (A and B group were killed 3 hr and 3 days, respectively, after BrdU i.p.). Most of BrdU positive cells were mesenchymal fibroblastic, and BrdU positive cardiac myocytes were a minor phenomenon during healing process. In cardiac myocytes, the BrdU labeling index is 0.49 +/- 0.02 and 0.05 +/- 0.01 at day 3 and 0 after injury, respectively (P < 0.05). All BrdU positive cardiac myocytes were located around myocardial necrosis. All BrdU positive myocytes in Group A were mononucleated, whereas some were binucleated in Group B. These results indicated that some of the cardiac myocytes could synthesize DNA reactively even after birth, and that in a healing process, myocytic DNA synthesis is probably followed by binucleated metamorphosis.

Animals↗
PubMed1994

F0F1-ATPase of Vibrio parahaemolyticus: purification using new detergents and characterization.

Previous attempts to isolate a stable F0F1-ATPase complex (H(+)-translocating ATPase) from Vibrio parahaemolyticus have been unsuccessful. Using new non-ionic detergents (alkyl thiomaltosides), a stable F0F1 complex with a high specific activity (15-25 units/mg protein) was purified and characterized. The purified F0F1-ATPase consists of eight subunits (alpha, beta, gamma, delta, epsilon, a, b and c). The new detergents, in combination with sucrose (or glycerol), lipid, dithiothreitol and phenylmethylsulfonyl fluoride, effectively stabilized the F0F1 complex. The ATPase activity of the F0F1 complex was greatly increased by anions, such as SO4(2-) and SO3(2-). Sodium ion increased the activity by about 2-fold. Dicyclohexylcarbodiimide, Zn2+, 4-acetamido-4'-isothiocyanostilben-2,2'disulfonate and tetrachlorosalicylanilide inhibited F0F1-ATPase activity. Ethanol, which stimulated F1-ATPase activity, inhibited F0F1-ATPase activity. Methanol, Na3VO4 and bafilomycin A1 did not have any significant effect on F0F1-ATPase activity, although methanol, like ethanol, stimulated F1-ATPase activity.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1994

Parathyroid Hormone-related Protein in Breast Cancer Tissues: Relationship between Primary and Metastatic Sites.

The expression of parathyroid hormone-related protein (PTHrP) at primary and metastatic sites was studied retrospectively in specimens obtained at opreation and autopsy from 11 patients. The anti-human PTHrP monoclonal antibody, 4B3, was used in the immunohistochemical studies. The 11 cases showed metastases to the liver and the lung, and 9 showed bone metastases at autopsy. At primary sites, PTHrP was positive in the 9 cases with bone metastases, while the other 2 cases were negative for PTHrP. Regardless of the intensities of immunohistochemical staining of PTHrP at primary sites, cancer cells at metastatic sites in the liver and the lung were almost all negative for PTHrP. On the other hand, all PTHrP-positive cases at primary sites at operation showed skeletal metastases at autopsy, and the intensity of the immunohistochemical staining of PTHrP was strongly positive at all the sites of skeletal metastasis. These results suggest that while PTHrP is an important factor that causes cancer cells to erode and grow in skeletal bone, the expression of PHTrP is, concurrently, affected by an osseous microenvironment.

Journal Article↗
PubMed1994

p53 gene abnormalities are closely related to hepatoviral infections and occur at a late stage of hepatocarcinogenesis.

Hepatocellular carcinoma (HCC) accumulates a mutation of the p53 gene with a common substitution of nucleotide in a particular site. It is hypothesized that infection of hepatitis B virus (HBV) or exposure to aflatoxins could induce it. In Japan, the concentration of aflatoxins in the environment is low; however, infection of HBV and/or hepatitis C virus (HCV) is frequently seen in patients with HCC. The purpose of our studies was to determine whether these hepatoviral factors influence p53 alterations. In our results, p53 abnormalities, which were composed of loss of heterozygosity (LOH) and/or point mutation, were shown in 39% of patients. We postulated that they occurred at late stages in tumor growth based on the following two results. LOH analysis on p53 showed that most of the tumor nodule consisted of two phenotypes, LOH and non-LOH cancer cells. The p53 abnormalities correlated with the grade of cancer cell atypia which advanced with tumor growth. HBV and HCV infections were identified by polymerase chain reaction using DNA extracted from cancerous and noncancerous regions of the liver. By these methods, the patients who had been infected with either HBV or HCV showed an incidence of p53 abnormalities (45%) higher than those infected by neither (13%). However, the detection rate of these viruses was lower in the HCC region (33%) than that in the noncancerous region (56%) in cases with mutated p53. The low rate of HCV detection (22%) in the HCC region with altered p53 was attributable to these different viral detection rates. There was a difference in pattern of p53 mutational changes in patients depending upon whether they were infected by HBV or by HCV. Two of three HBV-infected patients had a transversional change of nucleotide at the G:C site to T:A. However, in cases with HCV, four of eight patients had a transitional change of nucleotide of p53. These results showed that HBV and HCV infections affect carcinogenic pathways causing p53 abnormalities independently.

Adolescent↗
PubMed1994

The expression of parathyroid hormone-related protein in human breast cancer with skeletal metastases.

The relationship between the expression of parathyroid hormone-related protein (PTHrP) by breast cancer and skeletal metastases, was investigated using a monoclonal antibody against human PTHrP (4B3). The immunohistochemical localization of PTHrP was studied in sections of formalin-fixed, paraffin-embedded tissues from 28 breast cancers obtained surgically between 1980 and 1985. Of the 28 patients, 12 developed skeletal metastases, 8 developed lung metastases, and the other 8 were alive and disease-free at the time of this study. Sixteen of the 28 (57%) tumors showed positive immunoreactivity to 4B3, the PTHrP positive ratio being 83% in the patients who developed skeletal metastases, 38% in those who developed lung metastases, and 38% in those without recurrence, respectively. Thus, a significantly higher proportion of the patients who developed skeletal metastases were positive for PTHrP than the other two groups (P < 0.05). Furthermore, the level of positive staining was strongly related to positivity for estrogen and progesterone receptors (P < 0.01). These results are consistent with the hypothesis that PTHrP might be necessary for metastases to erode bone and grow in skeletal sites, and its expression could be related to certain hormones.

Antibodies, Monoclonal↗
PubMed1994

Quantitative EEG analysis at rest and during photic stimulation in drug-naive patients with first-episode paranoid schizophrenia.

In the present study, quantitative EEG analysis was performed at rest and during 10 Hz photic stimulation in 14 drug-naive patients with first-episode paranoid schizophrenia and 20 sex- and age-matched control subjects. Compared with the normal controls, the patients had significantly lower alpha-2 band amplitude in the resting EEG over all recording regions. No significant group differences were found in other frequency bands. In addition, EEG analysis during photic stimulation demonstrated that the patients had a rather uniform topographic profile in EEG amplitude for the alpha band, with significant group differences being confined to the posterior regions in the left hemisphere. There were no significant group differences in the amplitude for the frequency bands harmonically related to the stimulus frequency. These findings provide further evidence that schizophrenic patients have abnormal EEG activity in both non-stimulus and stimulus conditions, and suggest a dysfunction in the mechanisms underlying EEG alpha generation in schizophrenia.

Adult↗
PubMed1994

Uterine myxoid leiomyosarcoma and CYVADIC-etoposide therapy.

OBJECTIVES: To conduct a pathological characterization of rare uterine myxoid leiomyosarcoma (MLS) and establish an effective chemotherapy for metastasis after hysterectomy. METHODS: Histological and immunohistochemical methods were used to characterize the type of uterine MLS in a 39-year-old female. For multiple lung metastases found 3 months after operation, CYVADIC (400 mg cyclophosphamide, 1 mg vincristine, 50 mg epirubicin and 400 mg dacarbazine per body for one course) and oral etoposide (50 mg/body per day for 2 weeks) were applied. RESULTS: The rapidly enlarging uterine tumors exhibited gelatinous cut surfaces, a high count of 30 mitotic cells per 10 hpf and mucinous stroma, indicating a rare high-mitotic type of uterine MLS. The two-course CYVADIC-etoposide therapy was effective for disseminated pulmonary metastases. CONCLUSION: The present MLS was a rare high-mitotic type. CYVADIC-etoposide was an optional effective chemotherapy for lung metastasis in this case.

Adult↗
PubMed1994

[Acoustic analysis of certain consonants using a computed model of the peripheral auditory system].

Stop consonants [p], [t], [k] and a fricative [s] were acoustically analyzed using a computed model of the peripheral auditory system in 12 normal subjects and 12 patients with tumors of the tongue who had undergone surgical resection and reconstruction. The model is a combination of the cochlear model that consists of 28 FIR filters (Delgutte) and the inner hair-cell/auditory nerve synapse model (Meddis), with some modification. It simulates firing of the auditory nerve in every channel related to the FIR filters in response to an input voice signal. Phonetic characteristics of the tested consonants were more clearly visualized by observing firing patterns and voice onset time (VOT) using this auditory model than with use of the conventional soundspectrogram. In patients with tumors of the tongue, the degree of distorted articulation and the area of surgical resection were significantly related to obscurity of the phonetic characteristics of the stop consonants [t] and [k]. Acoustic analysis using this auditory model may serve as a useful tool for voice analysis in research and in the clinical field.

Computer Simulation↗
PubMed1994

[Quantitative analysis of EEG background activity in drug-naive schizophrenic patients].

In this study we performed quantitative EEG analyses in 12 drug-naive patients who fulfilled DSM-IIIR criteria for schizophrenia and in a group of 12 healthy subjects. The schizophrenic patients were found to have slower activity (delta and theta) than the controls. These differences were most marked in the frontal region for delta band and in the occipital region for theta band. The schizophrenic patients also had more beta 1 activity, particularly in the occipital leads. Conversely, they had less alpha 2 activity over all regions examined. Our findings indicate cerebral dysfunction in schizophrenia and are in line with the hypothesis of hypofrontality in this disorder.

Adult↗
PubMed1993

Parathyroid hormone-related protein in gastric cancers with heterotopic ossification.

BACKGROUND: Parathyroid hormone-related protein (PTHrP) has been regarded as one of the substances causing humoral hypercalcemia of malignancy. METHODS: The immunohistochemical localization of PTHrP was investigated in 33 cases of gastric cancer (4 with heterotopic ossification and 29 without heterotopic ossification) to clarify the role of PTHrP in heterotopic ossification by using the anti-PTHrP monoclonal antibody, 4B3. RESULTS: The four cases with heterotopic ossification showed positive staining at primary or metastatic sites, and in one case fibroblasts in the stroma surrounding the heterotopic ossifying foci also showed positive. On the other hand, of the 29 cases without heterotopic ossification, only 5 showed positive staining. CONCLUSIONS: The presence of PTHrP in ossifying gastric carcinomas at a relatively high rate indicates that PTHrP also might be related to heterotopic ossification associated with malignancies. It is speculated that PTHrP would contribute to heterotopic ossification by facilitating the process of mineralization.

Adenocarcinoma↗
PubMed1993

Common expression of parathyroid hormone-related protein and no correlation of calcium level in renal cell carcinomas.

BACKGROUND: Parathyroid hormone-related protein (PTHrP) is the predominant cause of humoral hypercalcemia of malignancy (HHM). METHODS: Using a PTHrP-specific monoclonal antibody (MoAb), 4B3, the authors investigated the immunohistochemical localization of PTHrP in formalin-fixed and paraffin-embedded sections of normal human kidney tissues and tissues from 42 human renal cell carcinomas obtained at operation or autopsy. RESULTS: In normal renal tissues, the distal tubules and collecting ducts showed positive immunostaining. PTHrP was detected in 40 of 42 renal cell carcinoma tissues (95%). Histopathologically, the granular cell subtypes of renal cell carcinomas tended to be more strongly positive than the clear cell subtypes. There was no significant correlation between the level of immunostaining and each patient's serum calcium level. CONCLUSION: PTHrP was commonly observed in renal cell carcinomas, and no significant correlation was seen between the intensity of PTHrP staining and the serum calcium level.

Antibodies, Monoclonal↗
PubMed1993

Candidate premotor neurones of skin reflex pathways to T1 forelimb motoneurones of the cat.

This study explored the locations and input-output properties of a large population of putative premotor neurones of skin reflex pathways in the cat. These neurones, interneurones excited by forelimb skin afferents and antidromically from the T1 motor nucleus (MN) and/or the lateral funiculus (LF, C8/T1 border), termed antidromic cells, were extracellularly recorded at C6-8. Selection of this site was based on data showing that cells retrogradely HRP labelled from the T1 MN were most numerous in C6-8 and the observation that transection of LF at the C8/T1 border abolished most skin-evoked postsynaptic potentials of T1 motoneurones. Antidromic cells were located in laminae IV-V, VI and VII. The latencies of antidromic excitation ranged from 0.4 to 1.8 ms, with a tendency for laminae IV-V cells to show longer latencies than laminae VI and VII cells. Latency of skin-evoked excitation ranged from 0.6 ms (IV-V cells), 0.8 ms (VI) and 1.4 ms (VII) to greater than 5 ms. The sum of the ortho- and antidromic latencies (estimated central latency) of individual cells explained the central latencies of skin-evoked postsynaptic potentials in T1 motoneurones. Skin-evoked firing responses (average of eight to ten cells) were earliest and largest in laminae IV-V antidromic cells, and latest and smallest in lamina VII cells. The antidromic cells who received inputs from muscle afferents and descending tracts. The following three results support the suggestion that the sampled antidromic cells are mostly premotor neurones. (1) Projection to the T1 MN via LF was verified in six laminae IV-VII antidromic cells, as tested with threshold mapping for antidromic excitation. (2) Three skin-excited axons of the middle LF projected to T1 MN, as revealed by intra-axonal staining (HRP). (3) PHA-L injection in laminae I-V of C8 anterogradely labelled terminals in lamina IX and LF axons at T1. It is suggested that last-order neurones of skin reflex pathways to T1 motoneurones are widely distributed in laminae IV-VII of C6-8 and consist of a variety of neurones with different locations and input patterns.

Animals↗