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Biomedical subjects

H Kajihara

Publications and source records attributed to H Kajihara.

At least 37 records · Page 2Linked to original sources
PubMed1996

Fine structural changes of muscle spindles in the gracile axonal dystrophy mutant mouse.

Fine structural changes of muscle spindles in the extensor digitorum longus of the gracile axonal dystrophy mutant mouse were studied from 20 to 120 postnatal days. Degenerative nerve endings in muscle spindles were first recognized at 20 postnatal days. The sensory nerve endings were usually swollen with decrease of cell organelles, and the cytoplasm was electron-lucent. At 50 postnatal days, atrophic nerve endings were frequently observed in the narrow spaces between the indented cell membrane of intrafusal muscle cells and the basement membrane. In addition to degenerative and atrophic changes, regenerative axons showing fine sprouts (with or without Schwann cell projections) appeared in the sensory nerve endings at this time. At 80 postnatal days, sensory nerve endings frequently showed dystrophic changes characterized by axonal dilatation with accumulations of neurofilaments, tubulovesicular structures, mitochondria and myelin-like figures. These findings suggest that axonal transport in the sensory nerve endings is impaired in this mutant mouse. Motor nerve endings were usually well preserved and normal structures even at 80 postnatal days. Intrafusal fibrosis, decrease in number of sensory nerve endings and atrophy of intrafusal muscle fibres were clearly recognized by 100 days of age.

Aging↗
PubMed1996

Ancient schwannoma of the oral floor and ventricular portion of the tongue: a case report and review of the literature.

We report a case of ancient schwannoma, which is a rare benign neoplasm of the oral floor and ventricular portion of the tongue. Only two cases have previously been reported in the English literature. The present tumor, measuring 5.5 x 3.0 x 3.0 cm, was the largest of the three. To differentiate ancient schwannoma from schwannoma with malignant transformation, it is important to confirm the absence of abrupt transition between areas of apparently typical schwannoma and areas composed of atypical large cells with pleomorphic and hyperchromatic nuclei, as well as the absence of mitoses, necrosis, and invasiveness. In the present case, calcification was not detected, nor was hyalinization extensive, although many of the neoplastic Schwann cells showed degenerative nuclear atypia.

Adult↗
PubMed1996

Hyaline cell-rich chondroid syringoma: epithelial nature of the hyaline cells.

We report a case of hyaline cell-rich chondroid syringoma arising in the skin on the left side of the neck. The tumor was composed exclusively of hyaline cells arranged in a predominantly thick trabecular pattern. Ductal structures of various sizes in the tumor were composed of eosinophilic cuboidal cells showing transition to hyaline cells. Immunohistochemically, the hyaline cells were positive for cytokeratin, S-100, and vimentin, although the best marker for myoepithelial differentiation, alpha-smooth muscle actin, was negative. As is the case with plasmacytoid monomorphic adenomas of the salivary gland and some reported cases of hyaline cell-rich chondroid syringoma, hyaline cells in the present tumor similarly lacked any evidence of myoepithelial differentiation. These immunohistochemical findings reveal that the hyaline cells in the present tumor were epithelial.

Adenoma, Pleomorphic↗
PubMed1996

A solitary Peutz-Jeghers-type hamartomatous polyp of the rectum: report of a case and review of the literature.

A solitary Peutz-Jeghers-type polyp of the rectum in a 64-year-old Japanese man is reported. Barium enema and endoscopic examination revealed a solitary polypoid lesion in the rectum. The polyp was pedunculated, and measured 2 x 1.5 x 1.5 cm. The patient had neither mucocutaneous pigmentation nor a family history of gastro-intestinal polyposis. Histopathologically, this polyp had an arborizing muscular network originating from the muscularis mucosa, and was covered by well organized mucosa with epithelial hyperplasia. The smooth muscle bundles in the polyp were thicker than those seen in Peutz-Jeghers syndrome, but their network was not as complex.

Hamartoma↗
PubMed1996

Effects of perfluorochemical-based artificial blood compounds in discordant xenotransplantation.

Fluosol-DA and FC43 emulsion were developed as red blood cell substitutes. However, these perfluorochemical (PFC)-based compounds are not very promising because of their immunosuppressive effects. Therefore we used these compounds as immunosuppressive agents in guinea pig-to-rat discordant heart xenotransplantations. In rats treated with these compounds (5 microliters/g body weight), rhythmic beating of the hearts was maintained for 265.7 +/- 50.3 min (Fluosol-DA-treated group) and 424.3 +/- 40.1 min (FC43 emulsion-treated group), respectively whereas the untreated heartbeat lasted for only 15.5 +/- 6.6 min. In the xenografted heart treated with PFC compounds, no pathologic changes, such as multiple coronary thromboses due to hyperacute rejection, had occurred by 3-4 h after reperfusion, and the endothelial cells were well preserved. We conclude that these PFC compounds can prolong the survival time of guinea pig heart xenografts by inhibiting thrombus formation in the xenografted heart.

Analysis of Variance↗
PubMed1995

[The effectiveness of perfluorotributylamine/pluronic F-68 stem-emulsion (FC43se) against xenograft rejection in the guinea pig-to-rat model].

The administration of perfluorotributylamine/pluronic F-68 stem-emulsion (FC43se), a fluorine compound emulsion, to a rodent discordant xeno-transplantation (dXT) model led to the discovery of the inhibitory effect of this compound against hyperacute rejection (HAR). When a guinea pig heart was transplanted to a rat administered with FC43se (10 microliters/g body weight), rhythmic beating was maintained for 1110 +/- 111.1 min (mean +/- SD; n = 8) whereas the untreated heart continued to beat for 15.5 +/- 6.6 min (mean +/- SD; n = 8). After 720 min of re-beating; pathologic changes observed in the untreated group, such as multiple thrombosis in the coronary vessels, were not observed in the FC43se-administered group by light and electron microscopic examination, and endothelial cells were well preserved. On the other hand, scattered necroses of the myocardium were observed and lymphocytic infiltration was demonstrated in the interstitium. We concluded that FC43se possessed a HAR inhibitory effect by inhibiting thrombus formation in the xeno-graft heart. Using this model, we speculated that action in the vessels of the graft heart (intravascular HAR) caused thrombus formation in the vessels. On the other hand, extravascular HAR causes myocardial necrosis more slowly, not resulting in cardiac arrest in the short term.

Acute Disease↗
PubMed1995

[Efferent spinal evoked potentials by transcranial magnetic stimulation in dog].

We have investigated the utility of transcranial magnetic stimulation for spinal cord monitoring, experimentally in dog. Experiment 1. Spinal cord potentials evoked by transcranial magnetic stimulation (TCMS) were recorded in the epidural space, using a bipolar mapping spinal electrode, and compared with potentials by transcranial electrical stimulation (TCES). Experiment 2. The effect of lateral compression on the spinal cord was observed, recording from 3 bipolar electrodes attached to the bilateral and dorsal midline epidural space. Experiment 3. The potentials evoked by TCMS were compared with the afferent potentials evoked by spinal electrical stimulation after lateral compression of the spinal cord. Efferent spinal cord potentials evoked by TCMS consisted of a 1 st component of high amplitude and short latency and a later polyphasic component with prolonged latency. The 1 st component was stable, and not affected by intravenous anesthesia. The potentials evoked by TCMS were similar to the potentials evoked by mild TCES, and the mean latency of the 1 st component by TCMS was very similar to that by mild TCES. After releasing the lateral compression, the amplitude recorded from the contralateral side of the spinal cord showed better recovery than that from the compression side. In experiment 3, for both potentials after good recovery, the latency was almost completely normalized, but the amplitude gradually decreased after two days. When there was relatively good recovery in the potentials by magnetic stimulation, the hind limbs resumed normal function. However when there was poor recovery in the potentials, the hind limbs showed a poor functional recovery. From these findings, we concluded that the potentials evoked by TCMS seem to reflect the function of the posterolateral portion of the spinal cord. These potentials were therefore a good indicator for monitoring the motor function of the spinal cord.

Animals↗
PubMed1994

Effects of naftidrofuryl oxalate on microsphere-induced changes in acetylcholine and amino acid content of rat brain regions.

Effects of naftidrofuryl oxalate (naftidrofuryl) on neurotransmitter, acetylcholine, and amino acid content of brain regions following microsphere-induced cerebral embolism were examined to elucidate its possible therapeutic effects on ischemic brain. Rats received 900 microspheres (48 microns in diameter) via the right internal carotid artery, followed by ligation of the right common carotid artery; and histological and biochemical alterations were examined on the 3rd, 5th, and 28th days after embolism. The embolism induced increases in triphenyltetrazolium chloride- (TTC)-unstained areas and decreases in acetylcholine, glutamate, aspartate, and gamma-aminobutyric acid (GABA) contents in the cerebral cortex, striatum, and hippocampus of the right hemisphere, suggesting that microsphere embolism causes severe damage to these brain regions. Hematoxylin-eosin staining of the right cortical sections after embolism showed degeneration and necrosis of nerve cells with chromatolytic nuclei and eosinophilic cytoplasm. Changes in neurotransmitters of the left hemisphere were relatively small. Treatment with naftidrofuryl of the embolized rats with stroke-like symptoms took place from postoperative day 1 to 28. Treatment resulted in a reduction in TTC-unstained areas, less morphological damage to cerebral cortex on the 3rd and 5th days, and an appreciable restoration of acetylcholine content of three brain regions of the right hemisphere throughout the experiment, but restoration of neurotransmitter amino acids was observed to a smaller degree. The results suggest that naftidrofuryl is capable of preventing the development of ischemia-induced, sustained damage to brain regions vulnerable to oxygen deficiency, particularly by improving impaired acetylcholine metabolism.

Acetylcholine↗
PubMed1994

Cardiorespiratory haemodynamics in haemorrhage and sepsis: a comparative study.

The standard wigger's method was used to induce haemorrhagic shock (HS) in anaesthetised dogs by bleeding to a mean arterial pressure (MAP) of 50mmHg for 2 hours and then to 30mmHg for 1 hour followed by reinfusion of the shed blood. Concurrent with this, endotoxin shock (ES) was also induced by intravenous infusion of Escherichia coli endotoxin in anaesthetised dogs. Cardiorespiratory function parameters in both experiments were recorded throughout the experiment on a multichannel poligraph monitor. The experimental protocol was designed to compare the effect of haemorrhage and sepsis on cardiopulmonary haemodynamics. Indices for cardiac performance, that is cardiac output (CO) and maximum dp/dt of left ventricular pressure (max dp/dt of LVP) were observed to deteriorate at a faster rate with sepsis than with haemorrhage while indices for pulmonary function, that is, pulmonary arterial pressure (PAP) and pulmonary vascular resistance (PVR) were shown to deteriorate much earlier and faster with sepsis than with haemorrhage. These experiments indicated that, cardiorespiratory disturbance is more severe with sepsis than with haemorrhage.

Animals↗
PubMed1994

Effect of immunomodulatory artificial blood exchange (IABX) on guinea pig-to-rat heart xenografts.

The aim of this study was to assess the effectiveness of pregraft immunomodulatory artificial blood exchange (IABX) in a guinea pig-to-rat xeno discordant heart transplantation, using an artificial blood (FC43 emulsion: The Green Cross, Japan) in exchange for a large volume of whole blood to remove humoral immune factors en bloc from the recipient rat. In the rats treated with IABX, rhythmic beating of the grafted heart was maintained for 2 hr, whereas the untreated heart beat lasted for only 15.2 +/- 5.2 min (n = 6). In the graft hearts treated with IABX, no pathologic changes such as multiple coronary thromboses due to hyperacute rejection (HAR) were observed. Humoral immune factors (natural-IgM titer, ACH50 and CH50 complement activities, platelet count, prothrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen serum concentration), which are thought to contribute to HAR, decreased significantly following the IABX treatment. We conclude that IABX is an efficient method for prolonging the survival time of guinea pig heart xenografts by inhibiting thrombus formation in the xeno-graft heart. It was confirmed that IABX could remove recipient humoral immune factors en bloc.

Animals↗
PubMed1993

Developmental changes in paramesonephric and mesonephric ducts and the external genitalia in swine fetuses during sexual differentiation.

The paramesonephric (Müllerian) duct was first observed in the vicinity of the mesonephric (Wolffian) duct in 30-day-old swine fetuses of both sexes at the level close to the gonad. The paramesonephric duct extended caudally in parallel with the mesonephric duct on day 35 of gestation. By day 40 the paramesonephric duct reached the urogenital sinus. At this stage, the paramesonephric duct began to degenerate in the male, while it continued to develop in the female. This suggests that an anti-Müllerian duct hormone (AMH) is produced before day 40 of gestation. By day 45 of gestation, the mesonephric duct began to decrease in diameter and was accompanied with the involution of the mesonephros in both sexes. By day 60, the male and female mesonephric ducts reduced in their diameter by 70%. Thereafter, the female mesonephric ducts disappeared, while the male ducts developed again. The sex differences was first observed on day 35 in the differentiation of the external genitalia when a small circular urogenital orifice and the anogenital raphe appeared at the sites caudal to the genital tubercle in the male. Such structures were not present in the female. These results suggest that the fetal pig testis is activated to secrete androgen before day 35 of gestation.

Animals↗
PubMed1991

Clinical analysis of reexpansion pulmonary edema.

Twenty-one of 146 cases of spontaneous pneumothorax that were treated by thoracentesis or continuous low negative pressure suction drainage (-12 cm H2O) of the pleural space developed REPE. The rate of REPE was higher in patients 20 to 39 years of age than in those over the age of 40, and the rate progressively increased in proportion to the extent of pneumothorax, as assessed by roentgenographic criteria. It is postulated that age-related changes in the lung may afford some degree of protection against developing REPE. It is also suggested that the treatment of pneumothorax with thoracentesis and/or suction drainage in young patients, or in the face of a large pneumothorax, requires careful consideration in view of a relatively high incidence of REPE in such individuals.

Adult↗
PubMed1990

Blastic transformation in essential thrombocythemia. In vitro differentiation of blast cells into granulocytic, erythroid, and megakaryocytic lineages.

A 57-year-old man with essential thrombocythemia (ET) developed myelofibrosis, that progressed to a blastic transformation state. The characteristics of the blastic cells were serially studied both morphologically and phenotypically as well as in cell culture. The blastic cells that were first detected in peripheral blood had features of myeloid stem cells with slight differentiation toward megakaryocytic lineage. However, later in the course, most of the blastic cells were immature. During culture in the presence of human plasma-derived serum (PDS), some blastic cells obtained at the initial stage differentiated, mainly to both granulocytes and macrophages morphologically, but later tended to differentiate into both megakaryocytes and macrophages. Finally the blasts appeared to have lost their ability to differentiate morphologically. However, the blasts formed mixed colonies consisting of erythroblasts, granulocytes, macrophages, and immature blasts when cultured in methylcellulose with PHA-leukocyte conditioned medium. In addition, the blastic cells in suspension culture strongly expressed phenotypic features which are characteristic of erythroblasts, in the presence of both PDS and 12-0-tetradecanoylphorbol 13-acetate (TPA), whereas they expressed features of megakaryoblasts in the presence of PDS alone. These results suggest that essential thrombocythemia is of myeloid stem cell origin. This is the first case in the literature in which a clonal evolution in ET has been followed closely, essential events were identified serially, and the blastic cells, which appeared as a result of the progression of ET, were found to have the capability to differentiate toward the three myeloid lineages.

Blast Crisis↗
PubMed1990

Structural changes of Kupffer cells in rat liver following experimental thermal injury.

Changes in plasma haemoglobin levels and morphology of Kupffer cells were studied in rats following lethal thermal injury. Severe haemolysis was observed immediately after thermal injury. The plasma haemoglobin levels rapidly increased to a maximum level 15 min after injury and then rapidly decreased with time. However, the values were still higher 5 h after injury than those found before injury. Soon after burning the Kupffer cells phagocytized not only circulating cell debris including erythrocyte membranes and degenerate leucocytes but also large amounts of haemoglobin. The degradation of phagocytized haemoglobin was relatively slow compared to that of other cell debris. This phagocytized haemoglobin is considered to inhibit the generation of bactericidal-free radicals and to depress Kupffer cell function. The number of Kupffer cells was markedly decreased 5 h after thermal injury, and probably relates to the persistent depletion of the reticuloendothelial system function which follows lethal thermal injury. In contrast to the decreased number of Kupffer cells, a small number of monocytic cells appeared in the sinusoidal spaces and adhered to the endothelial cells. These monocytic cells may transform into Kupffer cells.

Animals↗
PubMed1990

Aggressive natural killer cell leukaemia/lymphoma: report of four cases and review of the literature. Possible existence of a new clinical entity originating from the third lineage of lymphoid cells.

The morphologic, immunologic, genotypic and functional properties of peripheral blood and bone marrow cells or cultured cells from four patients with a clinically aggressive non-T, non-B natural killer cell leukaemia/lymphoma (ANKL/L) are described. The leukaemic cells possessed medium to large granules in the cytoplasm, antigens against CD38, CD2, OKIa 1 and NKH-1 CD56) monoclonal antibodies on their cell-surface, and also showed natural killer (NK) activity. In addition, these ANKL/L belonged to neither T- nor B-cell lineage, proved by studying clonal gene rearrangement for the T beta, T gamma and T delta receptors, and immunoglobulin. After comparing them with the seven cases of ANKL/L reported in other institutions, with regard to immunophenotype, genotype and function, we conclude that ANKL/L originating from a third lineage of lymphoid cells is a distinct clinical entity.

Adolescent↗
PubMed1990

A heterotopic cardiac transplantation model for evaluation of rejection using transvenous endomyocardial biopsy.

A model of heterotopic cardiac transplantation for diagnosis of rejection is described. Heterotopic cardiac transplantations were performed in the thorax using the left innominate artery as an arterial supply with venous return into the superior vena cava. Six pairs of mongrel dogs underwent cardiac transplantation using this technique. Two dogs died postoperatively on the 2nd and 3rd day due to respiratory failure. Another four donor hearts arrested their beats in 6 to 8 postoperative days (mean 6.3 days) resulting from acute cardiac rejection. Serial echocardiographic recordings were found to be a reliable measure of acute cardiac rejection, since the left ventricular wall thickness of the donor heart increased until the donor heart stopped by rejection. Endomyocardial biopsy was easy to perform by passage of flexible cardiac biotome into the right ventricle of the donor and the recipient heart through the right internal jugular vein. Pathological findings revealed that early changes of the donor heart were interstitial edema caused by myocardial ischemia. This was followed by lymphocyte infiltration around peripheral coronary arteries and acute rejection resulting in myocyte necrosis.

Animals↗
PubMed1989

[Aggressive natural killer cell leukemia/lymphoma--possible existence of a new clinical entity originating from the third lineage of lymphoid cells].

The morphologic, immunologic, genotypic, and functional properties of peripheral blood and bone marrow cells or cultured cells from two patients with a clinically aggressive non T, non B natural killer cell lymphoma/leukemia (ANKL/L) were described. The leukemic cells possessed medium to large granules in the cytoplasm, antigens against CD 38, CD 2, OKIal, and NKH-1 (N 901) monoclonal antibodies on their cell-surface, and also showed a high natural killer (NK) activity. In addition, these ANKL/L belonged to neither T-nor B-cell lineage, proved by studying clonal gene rearrangement for the T beta and T gamma receptor, and immunoglobulin. After we compared and investigated them with 9 cases of ANKL/L reported in other institutions, concerning immunophenotype, genotype and function, we reached the conclusion that the existence of ANKL/L originating from the third lineage in lymphoid cells is an obvious fact, suggesting this new clinical entity. It is important that all patients who have this type of a clinical disorder be diagnosed that there is no effective form of therapy at present.

Adult↗