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Biomedical subjects

T Kitamura

Publications and source records attributed to T Kitamura.

At least 613 records · Page 34Linked to original sources
PubMed1988

Quantitative studies on proliferative changes of reactive astrocytes in mouse cerebral cortex.

Cell number and proliferation of reactive astrocytes were studied quantitatively in the stabbed cerebral cortex of adult mice, using immunohistochemistry for glial fibrillary acidic protein (GFAP) and [3H]thymidine autoradiography. GFAP-positive astrocytes increased in cell number gradually from 24 to 96 h after stabbing, and their immunoreactivity became intense. The maximum number of GFAP-positive cells was about 4.5 times normal in the layers II-VI of the cortex, whereas it was only 1.5 times normal in the layer I (molecular layer). In contrast to the gradual increase in cell number, no GFAP-positive astrocytes were labeled with [3H]thymidine prior to 48 h after stabbing, in either the layer I or the layers II-VI. Then 3-5% of them were labeled at 72 and 96 h, but very few again after 6 days. By injecting [3H]thymidine successively for 6 days after stabbing, only 17% of GFAP-positive astrocytes of the layer I or the layers II-VI were labeled. These results reveal that, in the cortical layers II-VI, many GFAP-negative source cells initially express much more GFAP-antigen without proliferation and change into GFAP-positive reactive astrocytes. Proliferation of reactive astrocytes is not the major factor for the marked increase in number of them. The cortical layer I would have few GFAP-negative source cells for reactive astrocytes. These source cells may be protoplasmic astrocytes.

Animals↗
PubMed1988

Sequence of simian immunodeficiency virus from African green monkey, a new member of the HIV/SIV group.

Some wild African green monkeys are known to be naturally infected with a retrovirus related to human immunodeficiency virus (HIV) without having any apparent symptoms of an AIDS-like disease. This simian immunodeficiency virus, designated SIVAGM, may be helpful in clarifying the evolution and pathogenicity of HIV. Some virus strains that were previously reported to be isolated from African green monkeys were shown to be laboratory contaminations of SIVMAC (SIV from a rhesus macaque) Here we report the complete DNA sequence of authentic SIVAGM, which was isolated from a naturally infected African green monkey of Kenyan origin. Comparison of the genome of SIVAGM with those of known HIV/SIVs indicates that the virus is a new simian lentivirus that is approximately equally distantly related to HIV-1 and HIV-2 in contrast to SIVMAC, which is much closer to HIV-2 than to HIV-1 (refs 5, 9).

Amino Acid Sequence↗
PubMed1988

Expression of the functional erythropoietin receptors on interleukin 3-dependent murine cell lines.

Two distinct hemopoietic growth factors, interleukin 3 (IL-3) and erythropoietin (EPO), support the growth and development of erythroid cells in a sequential manner in vitro. Stimulation of multipotential stem cells by IL-3 appears to develop committed erythroid progenitor cells that respond to EPO. When several murine IL-3-dependent cell lines were assayed for their ability to respond to EPO, the growth and survival of the three cell lines showing the profiles of either myeloid or mast cell lineage (IC-2, DA-1, FDC-P2) were stimulated by EPO in a dose-dependent fashion. To determine whether the biologic effects were mediated through the specific receptors for EPO, we performed binding experiments on these cells with radioiodinated EPO. All of these cells displayed significant levels of specific binding for EPO. Among a family of hemopoietic growth factors, only unlabeled EPO was able to compete for the binding of radioiodinated EPO to the cells. Analysis of the binding data revealed the existence of a single case of binding sites in extremely low abundance. IC-2 cells were used to study the effects of IL-3 on the regulation of expression of EPO receptors. It was demonstrated that a decrease in IL-3 concentration in the culture medium increased the responsiveness to EPO and the amount in specific binding of EPO as well. These results suggest that some IL-3-dependent cell lines have functional EPO receptors and their expression may be modulated by IL-3.

Animals↗
PubMed1988

Biochemical changes before and during oral calcium tolerance test in calcium stone formers.

116 normocalcemic and 8 primary hyperparathyroid (PHPT) patients with calcium (Ca) nephrolithiasis and 10 normal controls underwent 1 g of oral Ca tolerance test following 4 days of Ca restricted diet (400 mg/day). On the basis of urinary Ca/creatinine (Cr) ratio obtained by the test, the 116 patients with normocalcemic nephrolithiasis were divided into 3 groups (normocalciuric nephrolithiasis; NN, absorptive hypercalciuria; AH, renal hypercalciuria; RH) according to our criteria which were slightly modified from Pak et al. Changes in urinary Ca/Cr ratio, and those in serum Ca and phosphorus (P), tubular maximum reabsorption of phosphate/glomerular filtration rate (TmPO4/GFR), nephrogenous adenosine 3',5'-monophosphate (NcAMP) and plasma immunoreactive parathyroid hormone (iPTH) were determined. As a result, the 116 patients were divided into 82NN, 13AH and 21RH. In general, a rise in serum Ca and fall in NcAMP were seen first, followed by rises in urinary Ca/Cr ratio, serum P and TmPO4/GFR although the changes were small. The group PHPT showed abnormality in the changes of TmPO4/GFR, NcAMP and plasma iPTH. The former one decreased constantly during the test and the latter two did not fall to within the normal range, suggesting parathyroid autonomy or abnormal suppressibility. Regarding the normal controls, all the changes were smallest among the 5 groups and clear parathyroid suppression was not observed while it was seen in the groups NN, AH and RH. In conclusion, oral Ca tolerance test is useful not only to separate NN, AH and RH, but also for the diagnosis of PHPT by demonstrating parathyroid autonomy or abnormal suppressibility assessed by NcAMP and/or TmPO4/GFR.

Administration, Oral↗
PubMed1988

Plasma levels of fluphenazine and prolactin in psychiatric patients.

A total of 100 patients receiving fluphenazine (FPZ) decanoate for at least 12 months (96 schizophrenics and 4 other diagnoses) were investigated for plasma levels of FPZ and prolactin on the day of injection (day 0) and 7 days later (day 7). The plasma FPZ level significantly correlated with the weekly dose of FPZ. The plasma FPZ level per weekly FPZ dose multiplied by 100 (the FPZ ratio) showed a 20-fold variation. The FPZ ratio was significantly higher in the day- and in-patients (hospital-patients) than in out-patients. The plasma prolactin level significantly correlated with the plasma FPZ level but the prolactin to FPZ ratio negatively correlated with the plasma FPZ level. The prolactin to FPZ ratio was lower in the hospital patients than in the out-patients. This may suggest either that the high prolactin to FPZ ratio is an indicator of the therapeutic efficacy of FPZ or that there are at least two biologically distinct subgroups, one with a sharp prolactin response to FPZ, therefore with good prognosis, and another with the reverse direction.

Adult↗
PubMed1988

A quantitative analysis of human astrocytosis.

The number of astrocytes in an atrophic human brain was counted with the aid of immunohistochemistry for glial fibrillary acidic protein. Microscopically, astrocytosis was remarkable in the cerebral neocortex and white matter. Taking the cortical atrophy into consideration, however, the total number of astrocytes in the cortical layers II-VI was not increased. The number of astrocytes in the white matter was not increased either. It is indicated that astrocytosis does not always mean hyperplasia (net increase of total number) of astrocytes.

Astrocytes↗
PubMed1988

Medullary sponge kidney and hyperparathyroidism.

Medullary sponge kidney (MSK), parathyroid adenoma, renal cell carcinoma, and renal-leak hypercalciuria coincided in 1 female patient. Renal-leak hypercalciuria was not corrected by removal of a parathyroid adenoma. Since the patient had renal tubular acidosis (RTA), alkali treatment was conducted and resulted in the correction of hypercalciuria. Renal cell carcinoma eventually developed and MSK was confirmed histologically. This case suggests that MSK and primary hyperparathyroidism occurred independently.

Calcium↗
PubMed1988

A new screening test for dementia.

The purpose of this study is to develop a new screening test for detecting the demented elderly in the early stage in communities. The test is easy to apply for consultation, guidance and care and is capable of administering differential diagnoses. Based on the 9 dementia rating scales used in Japan, Europe and the U.S., a new test was completed after investigating and modifying the design 5 times. The test consists of 20 items. This test was given to 203 subjects (59 males and 144 females) including normal elderly as well as those suspected of suffering from dementia. The internal consistency, reliability and validity were studied using clinical diagnoses (diagnostic criteria of Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III) and Karasawa's Criteria for Judging Senility), Hasegawa's Dementia Rating Scale and Mental Status Questionnaire (MSQ) as external criteria. The present test was confirmed to have sufficient effectiveness as the screening test for dementia.

Aged↗
PubMed1988

Hepatocellular carcinoma arising in the abdominal cavity. An autopsy case of ectopic liver origin.

An unusual case of extrahepatic disseminating hepatocellular carcinoma in a 64-year-old man is reported. The initial symptom was abdominal fullness and progressive ascites. Alpha-fetoprotein in the serum was 117,000 ng/ml. Exploratory laparotomy disclosed dissemination of tumor nodules throughout the abdominal cavity without any other possible primary tumor. CT scan, ultrasonography and hepatic angiography were unable to detect any tumor lesion in the liver. The final histologic diagnosis was hepatocellular carcinoma, although at first epithelioid mesothelioma was suspected. The present case of hepatocellular carcinoma was thought to have possibly developed from ectopic liver on the peritoneum.

Abdominal Neoplasms↗
PubMed1988

Bile canalicular contraction in the isolated hepatocyte doublet is related to an increase in cytosolic free calcium ion concentration.

Dynamic contractions of bile canaliculi have been observed in cultured doublet hepatocytes by means of time-lapse cinephotomicrography, and this contractile movement plays an important role in bile secretion. Although details of the mechanism are still unknown, the Ca2+-calmodulin system is believed to play a main role in this mechanism. In this study we measured the intracellular Ca2+ concentration of individual doublet hepatocytes using the Ca2+ indicator "fura 2" and microscopic fluorometry. We also observed the effects of A23187, norepinephrine and epinephrine on bile canalicular contraction and intracellular Ca2+ concentration. After loading 1 mumol/l fura 2 in doublet cells, we added A23187, epinephrine or norepinephrine and then measured the Ca2+ concentration in a given small area in the cytoplasm of individual doublet cell. A23187, norepinephrine and epinephrine caused a prompt increase of the intracellular Ca2+ concentration and also caused bile canalicular contraction. The present study indicates that the sudden increase of intracellular Ca2+ concentration causes bile canalicular contraction through the Ca2+-calmodulin system.

Animals↗
PubMed1988

[A case of primary hepatoma with marked reduction of the tumor after oral administration of tegafur].

A 57-year-old male complaining mainly of pain in the right terminal rib area was admitted to hospital for hepatic tumor examination. Primary hepatoma with infiltration of the inferior vena cava was diagnosed by various imaging techniques and the subject was started on a program of daily oral administrations of 800 mg of tegafur. Prior to commencing drug administration the hepatic tumor measured 112 x 80 mm; after four months of treatment the tumor was reduced to 56 x 48 mm and the infiltration in the inferior vena cava had disappeared. The tumor continued to decrease in size thereafter, and today measures 32 x 28 mm after three years of tegafur administration. The subject continues to be monitored as an outpatient. A marked reduction in the size of a hepatic tumor was observed in this case, and the administration of tegafur has proved effective in prolonging life for over three years.

Administration, Oral↗