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Biomedical subjects

I Tanaka

Publications and source records attributed to I Tanaka.

At least 361 records · Page 20Linked to original sources
PubMed1991

Cadmium toxicity in the thyroid gland of pregnant rats.

The toxic effects of cadmium on the thyroid gland of pregnant rats were studied with an electron microscope and an X-ray microanalyzer. Serum levels of thyroid hormones (T3 and T4) were also analyzed. Deterioration of the rough-surfaced endoplasmic reticulum occurred in the thyroid follicular epithelium on the fifth day of cadmium treatment. Large intracellular vacuoles, which arose from dilated cisternae of the rough-surfaced endoplasmic reticulum, were fused together, and marked swelling of the mitochondria was also noted. Thyroglobulin-secreting granules at the apical cytoplasm were decreased in number. By energy dispersive X-ray microanalysis, cadmium peaks were preferentially obtained from swollen mitochondria in the follicular epithelial cells. Serum levels of T3 and T4 were significantly decreased in cadmium-treated rats dams when compared to those of controls. In the present experiment, cycloheximide also caused degenerative changes in the rough-surfaced endoplasmic reticulum and the disappearance of thyroglobulin-secreting granules. Cycloheximide is a known inhibitor of protein synthesis on cytosolic ribosomes. These results indicated that accumulated cadmium in the mitochondria of thyroid follicular epithelial cells might disturb the oxidative phosphorylation of this organelle and the loss of energy supply possibly caused the inhibition of the synthesis and release of thyroid hormones.

Animals↗
PubMed1991

Analysis of the forelimb crossed extension reflex in thalamic cats during stepping.

Forelimb crossed extension reflexes were examined in 22 thalamic cats. These reflexes were elicited either by backward passive movement or by repetitive electrical stimulation of cutaneous and joint afferent nerves in the contralateral forelimb. Single stimulation of the superficial radial nerve evoked two types of reflex responses--early (ER) and late (LR)--from the triceps brachii muscle on the contralateral side. The latencies were about 7 and 16-25 ms, corresponding to the propriospinal (PSR) and spino-bulbo-spinal (SBS) reflexes of the ipsilateral flexor, respectively. Repetitive stimulation of the superficial radial nerve evoked the LR but not the ER. The crossed extension reflex and LR were abolished by lesions of the dorsolateral funiculus of the cervical cord on the side opposite to the recording. The tonic EMG activity, crossed extension reflex and LR in the extensor on the side of lesions were abolished by lesions of the ventrolateral funiculus of the cervical cord. During forelimb stepping, the amplitudes of both ER and LR fluctuated depending on the phase of the step cycle. The ER appeared during a narrow period in the early phase of the stance, whereas the LR was observed during a wide period from the middle of the swing to the middle of the stance. Both responses were absent from the middle of the stance to the middle of the swing. These observations suggest that forelimb crossed extension reflexes involve both spinal and supraspinal (SBS) loop mechanisms, and that these are utilized during stepping, with the latter mechanism in particular playing an important part in the extension phase of the forelimb forward movement.

Afferent Pathways↗
PubMed1991

Atrial natriuretic peptide and brain natriuretic peptide coexist in the secretory granules of human cardiac myocytes.

To elucidate the intracellular localization of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in human cardiac myocytes, an immunocytochemical study was carried out by a double immunogold technique using antisera highly specific for ANP and BNP. Surgical and autoptic tissue specimens of human heart were studied. In the atrial myocytes, ANP was localized in almost all of the secretory granules, whereas BNP was colocalized with ANP in some of the granules. Although very few secretory granules were observed in ventricular myocytes, colocalization of ANP and BNP was basically the same as in atrial myocytes. No immunoreactive products were found in the control studies. These results suggest that secretion of BNP is under a regulatory mechanism similar to that of ANP.

Atrial Natriuretic Factor↗
PubMed1991

Reconstruction of two separated electrical burn ulcers.

In this study, we describe the reconstruction of composite tissue defects in two separated regions (left elbow and right thigh) using only one-sided rectus abdominis myocutaneous flap. We report here the results of our procedure, as it increases the usefulness of the rectus abdominis myocutaneous flap and can be applied to other clinical situations.

Adult↗
PubMed1991

Dose dependent effects of inhaled ethylene oxide on spermatogenesis in rats.

Male Wistar rats were exposed to ethylene oxide (EO) at concentrations of 50, 100, or 250 ppm for six hours a day, on five days a week for 13 weeks. Dose effect relations of inhaled EO on spermatogenesis were evaluated from testicular and epididymal weights, histopathological changes and lactate dehydrogenase X (LDH X) activity in the testis, and sperm counts and sperm head abnormalities in the epididymis. At 250 ppm, a decrease in epididymal weights, slight degenerations in the seminiferous tubules, decreased sperm counts, and increased numbers of abnormal sperm heads in the tail of the epididymis were found; these were not seen at lower doses. When the abnormal sperm heads were classified into immature types and teratic types, the number of immature heads increased only at 250 ppm. On the other hand, the teratic type had increased at doses of 50 and 100 ppm EO when compared with the control group. Hence, subchronic inhalation of EO at low concentrations affects spermatogenesis in rats.

Alkylating Agents↗
PubMed1991

Experimental lung injury induced by trimellitic anhydride inhalation on guinea pigs.

Trimellitic anhydride (TMA) causes lung injury by inhalation exposure in humans. In order to investigate more precisely the mechanism of lung injury by TMA, an experimental animal model of TMA-induced lung injury was established. Guinea pigs were intramuscularly injected with trimellitylated bovine serum albumin (TM BSA) with complete Freund's adjuvant (CFA). Appreciable amounts of antibodies against TM epitopes were detected in the sera of these animals. Guinea pigs that were passively sensitized with anti-TM antisera as well as the actively immunized animals developed hemorrhagic pneumonitis after TMA inhalation. It is well recognized that hyperimmune antisera of guinea pigs contain two subclasses of IgG antibodies, IgG1 and IgG2, which are known as homocytotropic and heterocytotropic antibodies, respectively. To determine the role of these antibodies in the airway injury with alveolar hemorrhages, they were isolated by gel filtration and by ion exchange column chromatography, and the guinea pigs that were sensitized with each of these antibodies were exposed to TMA inhalation. The extent of lung injury in these animals was quantitatively determined by the measurements of lung extravasation of Evans blue dye injected intravenously after TMA inhalation. Significant increases in the extravasation of dye were observed in both animal groups sensitized with IgG1 and IgG2 antibodies. In addition, results obtained with heat-treated antisera and IgG1 antibody did not significantly differ from those obtained with untreated samples. These results suggest that the lung injury resulting from TMA inhalation exposure can be induced with humoral antibodies, not only IgG1 but also IgG2, and that at least two types of allergic reactions are involved in the pathogenesis of lung injury.

Alveolitis, Extrinsic Allergic↗
PubMed1991

[Inflammatory type of malignant fibrous histiocytoma in the anterior mediastinum--a case report].

A 58-year-old female was admitted to our hospital with a complaint of anterior chest tumor, fever of unknown origin and anemia. Chest X-ray films and chest CT scans revealed a large tumor in the anterior mediastinum, there were strong inflammatory reactions in laboratory studies. The tumor was resected with a part of the rt anterior chest wall. The partial resection of the upper and middle lobe of the rt lung and the pericardium which were invaded of the tumor were performed. Postoperative course was uneventful and body temperature went down. Inflammatory reaction and anemia got also improved. In histological findings, both rounded histiocyte-like and spindled fibroblast-like tumor cells were arranged in a random or haphazard fashion and showed a storiform pattern. And there was a collection of xanthoma-like foamy cells and invasive inflammatory cells. So the histological diagnosis was inflammatory type of MFH. As far as we investigated, this case was the 23rd mediastinal MFH in the world literature.

Female↗
PubMed1991

Epitope localization of monoclonal antibodies against factor VIII light chain which inhibit complex formation by factor VIII with von Willebrand factor.

We obtained three clones of monoclonal antibodies against factor VIII by immunization with purified human factor VIII. The anti-factor VIII procoagulant activity of these antibodies ranged from 2 to 53 Bethesda units/mg of IgG. According to an immunoblotting study, all antibodies reacted with the 80 kDa light chain but not with 72 kDa peptides derived from thrombin digestion of factor VIII. We attempted to localize the antigenic epitopes of these antibodies by a competitive blocking assay using synthetic peptides and recombinant fragments of the amino-terminal region of factor VIII light chain. In the former assay, a 50 microM peptide containing the fifteen amino acid residues from the Val1670-Glu1684 completely inhibited the binding of the three monoclonal antibodies to immobilized factor VIII. In the latter experiment, 13 reactive recombinant peptides were obtained. Sequences of these peptides revealed fourteen overlapped amino acid residues from Glu1675 to Pro1688. All three antibodies at a final concentration of around 10 micrograms/ml completely inhibited the binding of 125I-labelled factor VIII to immobilized von Willebrand factor (vWF). We conclude that ten amino acid residues, 1675EDFDIYDEDE1684 in the factor VIII light chain are important for complex formation with vWF.

Antibodies, Monoclonal↗
PubMed1991

Changes in polypeptide-specific factor VIII antigen levels during whole blood clotting.

The time-course of factor VIII (FVIII) proteolysis during whole blood coagulation was monitored using polypeptide-specific enzyme-linked immunosorbent assays (ELISAs) developed with monoclonal antibodies to FVIII. Such assays of whole blood from normal subjects revealed that, within 30 min after coagulation had started, levels of the amino-terminal region of FVIII light chain and in the middle region of FVIII heavy chain had decreased to baseline in parallel with factor VIII procoagulant activity, but that levels of the 70 kDa thrombin digest decreased more slowly, with 75 U/dl of FVIII antigen (FVIII:Ag) remaining even after 2 h. Similar analysis of the blood of a patient with congenital hypoprothrombinemia indicated a lag phase of 20 min before proteolysis started. No significant change was observed until 1 h after calcium chloride was added to prothrombin-depleted plasma. On the other hand, in the presence of tissue thromboplastin, levels of FVIII:Ag in all ELISAs decreased rapidly. These results indicate a requirement for thrombin generation in the proteolysis of FVIII during the process of whole blood clotting.

Blood Coagulation↗
PubMed1991

Clinical evaluation of recombinant human factor VIII (BAY w 6240) in the treatment of hemophilia A.

A pilot clinical trial was conducted in five patients with severe hemophilia A to evaluate the safety and efficacy of a recombinant human factor VIII preparation, BAY w 6240 (rFVIII). In a comparative pharmacokinetic study of rFVIII and a plasma-derived factor VIII preparation (pdFVIII), the mean t1/2 values for rFVIII at week 1 and week 13 were 16.8 and 14.4 h, while this value for pdFVIII at week -2 was 16.9 h. There were no statistical differences between these values. The mean in vivo recovery rates of rFVIII were comparable to those of pdFVIII. When rFVIII was administered prophylactically three times a week for 4 weeks, no bleeding episodes were observed. Seventy-four bleeding episodes were assessed during the 6-month treatment period. The efficacy rate of the hemostatic effect was confirmed to be 95.9%. No adverse reactions attributable to rFVIII were observed in a total of 178 infusions. Neither FVIII-inhibitors nor antibodies to foreign proteins were detected. Vital signs and laboratory findings showed no significant changes attributable to rFVIII. These results suggest that rFVIII is safe and efficacious as replacement therapy for hemophilia A.

Adult↗
PubMed1991

[Primary pulmonary hemangiopericytoma].

Hemangiopericytoma seldom originates from the lung. Only 63 cases in the English literature and 30 cases in the Japanese literature have been reported. A 38-year-old female is presented in this paper. The patient was asymptomatic and was found a coin lesion of the left middle lobe by routine examination. She underwent tumorectomy and has been alive and well for 5 years. 1) The differential diagnosis of hemangiopericytoma from several other tumors is often difficult, as pericytes show no distinctive features on light microscopy. Therefore, it is emphasised that EM studies are obligatory to confirm the diagnosis of this tumor. 2) The origin of vessels with a characteristic staghorn appearance on light microscopy have not been described in previous papers. Bronchial arteriography in this case revealed that tumor vessels arose mainly from the bronchial artery.

Adult↗
PubMed1991

[A case of jejunal metastasis from pulmonary adenocarcinoma occurring as perforative peritonitis].

On first admission on June 5, 1989, pulmonary adenocarcinoma of left S3b in a 62-year-old male had already metastasized to the brain and the clinical stage was T2N2M1. Radiation therapy for the metastatic brain lesion was very successful but chemotherapy for the primary lesion was not effective. He was discharged on August 24, 1989. He was readmitted to our hospital on Jan. 5, 1990 because of severe abdominal pain. His chest roentgenogram showed free air under the diaphragm. An emergency laparotomy was performed, because perforation of gastrointestinal tract was suspected. At operation, two localized tumors were found, one located in the jejunum approximately 20 cm distal to the ligament of Treitz, accompanied by perforation and another approximately 20 cm distal to the above lesion in the mesentery. The resected specimen of the perforated lesion demonstrated a deep and large ulcer, compared to the tumor size, similar to a submucosal tumor, accompanied by bridging folds. The pathologic interpretation was adenocarcinoma of the lung metastatic to the jejunum and mesentery. Primary lung cancer metastasizes to a wide variety of organs, but metastasis to the small intestine is uncommon, even on postmortem examination. Furthermore, it is rare that the metastatic lesion causes abdominal symptom leading to laparotomy.

Adenocarcinoma↗
PubMed1990

[The amount of nitrogenous oxygen demand (NOD) in BOD--study on effluents and influent from biological treatment plants and river waters in Kitakyushu area].

BOD (Biochemical Oxygen Demand) is utilized widely as an index of water quality. However, nitrification is a cause of significant errors in measuring BOD, particularly when a large population of nitrifying organisms are existing in water such as effluents from biological treatment plants. In this case, the use of a nitrification inhibitor is recommended, but it is not used commonly. In order to investigate the amount of nitrogenous oxygen demand (NOD) which is caused by nitrification, BOD with and without inhibitor was measured as samples in the Kitakyushu area. About 70 percent of BOD from the effluents of biological treatment plants was NOD. In the case of influent of biological treatment plant and river waters, 0-39 percent of NOD was contained in BOD.

Japan↗
PubMed1990

Crossed forelimb extension produced in thalamic cats by injection of putative transmitter substances into the paralemniscal pontine reticular formation.

To analyze the descending pathways of the paralemniscal pontine reticular formation (PLRF), a technique was used for the selective activation of cell bodies by localized injection of putative neurotransmitters in the PLRF. When a small amount (less than 0.1 microliter) of 0.1 M glutamate was injected into the PLRF unilaterally in thalamic cats, the forelimb contralateral (c-forelimb) to the injection was extended, and occasionally the ipsilateral forelimb was flexed. These responses were similar to those obtained by electrical stimulation of the PLRF, but were relatively weaker. Unit spikes of PLRF neurons were increased in frequency following administration of glutamate. The latent periods and durations of increases in spike frequency varied depending on the concentration and quantity of the glutamate solution, and were roughly similar to those of the extensor EMG in the c-forelimb. Since the firing of PLRF neurons preceded the EMG with 11 ms latency, the unit spike of PLRF neurons could be used as a triggering signal to observe a spike triggered averaged EMG response in the extensor muscle of the c-forelimb. Results similar to those with glutamate were observed upon administration of quisqualate, kainate and aspartate. The most effective compound was quisqualate. Application to the PLRF of 1-naphthylacetyl spermine (1-NA-Spm), an analogue of the natural spider toxin JSTX-3 and an antagonist of glutamate, suppressed both the PLRF neuron activity and the extensor EMG of the c-forelimb. These observations suggest that extensor muscles of the forelimb are excited by the contralateral PLRF, perhaps via the crossed reticulospinal tract from the PLRF. PLRF neurons may be activated by glutamate (quisqualate) receptors.

Animals↗