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Biomedical subjects

R Kaji

Publications and source records attributed to R Kaji.

At least 145 records · Page 8Linked to original sources
PubMed1990

[A case of mild obesity accompanied by epicardial fat deposition].

A 61-year-old woman with low grade obesity index complained of general fatigue. Cardiomegaly had been present since the age of 45. According to a roentgenogram on admission, her cardia-thoracic ratio was 61%. Pericardial effusion was strongly suspected because of extra echo spaces on both posterior and anterior walls, and unsynchronized echocardiograph waves of epicardium and pericardium. However, values of dynamic CT measured at areas equivalent to the extra echo spaces were -120. On admission, T1-emphasized MRI image showed a high signal density in those areas. After significant weight reduction, the abnormal values and signs of the clinical examinations, as well as the patient's complaints were attenuated or disappeared. Together with these results, cardiomegaly of the patient was diagnosed to be due to excessive fat deposit between the epicardium and cardiac muscle. Dissociation between mildness of obesity index and excessive deposition of fat in the pericardium was discussed from the point of view of body mass index and time course of fat deposition.

Adipose Tissue↗
PubMed1990

Induction of bone formation in an adenoid cystic carcinoma of the maxillary sinus by adoptive immunotherapy involving intra-arterial injection of lymphokine-activated killer cells and recombinant interleukin-2 in combination with radiotherapy.

A patient with an adenoid cystic carcinoma of the maxillary sinus was treated by adoptive immunotherapy involving intra-arterial injection of lymphokine-activated killer cells (a total number of 7 x 10(7) cells) and recombinant interleukin-2 (a total dose of 2.75 x 10(7) units) in combination with radiotherapy (60Co; total irradiation dose of 5,000 rads). Consequently, it was found that bone formation was induced in the treated tumor, which was then replaced completely by lamellar bone tissue with myxomatous stroma. This finding indicates that the tumor cells composing certain adenoid cystic carcinoma can be converted into normal-appearing, bone-forming cells by current therapy and this differentiation phenomenon leads to cure of the tumor.

Biopsy↗
PubMed1989

Expression of neurofilaments in a neoplastic human salivary intercalated duct cell line or its derivatives and effect of nerve growth factor on the cellular proliferation and phenotype.

A neoplastic salivary cell line with an ultrastructure similar to that of an intercalated duct cell of the salivary gland, established from a human submandibular salivary gland, has been used in our laboratory as a model for studying mechanisms regulating cytodifferentiation in salivary glands. The expression of neurofilaments (Mr 200,000, 160,000, and 68,000) in the neoplastic human salivary intercalated duct cell line and its derivatives was found by the immunofluorescence staining technique, immunoblotting, or immunoelectron microscopy. In addition, these cells stained with Bodian impregnation and expressed specific antigens such as tubulin alpha and beta chain, HNK-1 antigen, and laminin. When these cells were cultured in the presence of nerve growth factor, only the cells with a myoepithelial cell phenotype formed the long cytoplasmic processes which were densely packed with ample microfibrils in addition to microtubule bundles, and they exhibited marked suppression of anchorage-independent and anchorage-dependent growths. These findings indicate that the characteristics of neoplastic human salivary intercalated duct cell line and its derivatives are similar to those of neuronal cells.

Biomarkers↗
PubMed1989

Effect of digitalis on central demyelinative conduction block in vivo.

In searching for agents effective in treating multiple sclerosis, we studied the effect of a short-acting digitalis, ouabain, on conduction block in an animal model of central nervous system demyelination. The electrogenic sodium/potassium pump, which digitalis specifically inhibits, is responsible for part of the resting membrane potential and also the activity-related membrane hyperpolarization following high-frequency impulses. The latter causes intermittent conduction block in demyelinated fibers. Therefore, digitalis might be expected to reverse demyelinative conduction blocks by reducing the threshold at the blocking node. Somatosensory evoked potentials were monitored in 11 rats with spinal cord demyelination before and after systemic administration of ouabain (0.1-0.6 mg or 0.21-1.58 mg/kg IP). In all rats, slowed conduction velocity of the compound action potential through the lesion was significantly reversed, and failure to transmit high-frequency impulses was improved upon. The amplitude of the cortical somatosensory evoked potentials also increased significantly. Digitalis is a promising therapeutic agent for trial in patients with multiple sclerosis.

Afferent Pathways↗
PubMed1989

Slow recovery of central axons in acrylamide neuropathy.

To study the differential vulnerability of central versus peripheral axons, we observed serial changes in conduction over comparable segments of central and peripheral axons of the primary sensory neuron in 17 rats with acrylamide neuropathy using somatosensory evoked potentials. Central conduction abnormalities persisted even after peripheral conduction and clinical abnormalities had recovered. Morphometric studies showed prompt restoration of the largest-diameter fibers in the peripheral nerve after clinical recovery but persistent or even more severe loss of large- and medium-sized fibers in the cervical gracile tract. This finding suggests that recovery from central-peripheral distal axonopathy begins in the largest peripheral axons, perhaps even at the expense of central axons, and that clinical recovery can occur at a time when central conduction remains abnormal. The selective central axonopathy found in certain chronic degenerative disorders may be a consequence of this slow central recovery process associated with chronic or intermittent metabolic derangements.

Acrylamides↗
PubMed1989

Ouabain reverses conduction disturbances in single demyelinated nerve fibers.

Symptoms in patients with demyelinating disorders are associated with 3 important conduction abnormalities: complete conduction block, rate-dependent conduction block, and slowed impulse conduction. The recent observation that the electrogenic Na/K pump causes the nerve membrane hyperpolarization responsible for rate-dependent conduction block in demyelinated axons raises the possibility that focal inhibition of the pump may reverse the rate-dependent block. Since the pump is also responsible for maintaining part of the resting membrane potential, pump inhibition might have an additional effect of reversing the complete conduction block by reducing the threshold. We have demonstrated that inhibition of the pump by topical application of ouabain, a short-acting cardiac glycoside, reverses the conduction abnormalities in acutely demyelinated single rat ventral root axons by reducing the threshold of transmission. Ouabain or other cardiac glycosides show potential promise as agents for trial in the symptomatic treatment of patients with MS and other demyelinating disorders.

Animals↗
PubMed1989

Monoclonal antibody to a human salivary gland adenocarcinoma cell line: augmentation of antibody-dependent cell-mediated cytotoxicity activity by streptococcal preparation OK-432 in human salivary gland adenocarcinoma-bearing nude mice given the antibody.

An IgG2a mouse monoclonal antibody (MoAb) to the human salivary gland adenocarcinoma cell line HSG, 5B/10, has been generated in our laboratory. In the current study, the antitumor effects mediated by MoAb 5B/10 in human salivary gland adenocarcinoma (HSG)-bearing nude mice or the antibody-dependent cell-mediated cytotoxicity (ADCC) against HSG cells using human peripheral blood mononuclear cells (PBMC) as effector cells were examined. In addition, effects of the streptococcal preparation OK-432 on the growth of HSG tumors or on the MoAb 5B/10-mediated cellular cytotoxicity were studied. MoAb 5B/10 mediated an ADCC reaction against HSG cells that were insensitive to NK cells but not to the reaction of antibody and complement-mediated cytotoxicity. The coexistence of MoAb 5B/10 and OK-432 caused marked augmentation of cytotoxic effects. Treatment of OK-432-stimulated PBMC with antiasialo Gm1 antiserum plus complement but not with silica particles resulted in a significant decrease of cytotoxic effects as compared with relevant controls. the nude mice inoculated intraperitoneally with HSG cells and treated with MoAb 5B/10, OK-432, or (especially) a combination of the two had significantly prolonged survival times as compared with untreated controls. Moreover, spleen cells from the tumor-bearing mice treated with OK-432 alone or a combination of MoAb 5B/10 and OK-432 were found to carry high levels of effector cell activity in the MoAb 5B/10-mediated cytotoxicity assay using HSG cells as targets.

Adenocarcinoma↗
PubMed1988

Physiological consequences of antiserum-mediated experimental demyelination in CNS.

To study the pathophysiology of immunologically mediated demyelination in the central nervous system (CNS), we injected 20 to 30 microliters of polyclonal antigalactocerebroside serum (AGC) into the lower thoracic dorsal column of the spinal cord in 20 Wistar rats. AGC-injected spinal cords contained areas of fascicular demyelination adjacent to the focus of axonal degeneration at the injection site. Somatosensory evoked potentials were recorded serially after tibial nerve stimulation. In 85% of AGC-injected animals, the following characteristics were observed by 3 days after injection: (1) decreased amplitude of the cortically generated potential (P15); (2) failure of transmission of high-frequency (50 Hz) impulses (rate-dependent block); (3) delayed conduction velocity of the compound action potentials through the lesion. None of these changes was seen in 90% of 20 rats injected with normal saline or control rabbit sera. In 7 rats with acrylamide-induced axonopathy or wallerian degeneration, the rate-dependent block was not observed. The onset of clinical symptoms (hindlimb ataxia) in AGC-injected rats was best correlated with development of the rate-dependent block. Clinical recovery was observed by 14 days after injection concurrent with restoration of P15 amplitude, when the rate-dependent block and decreased conduction velocities were unchanged. High-frequency-resistant conduction was re-established much later than clinical recovery in 3 rats. These findings suggest that failure of high-frequency impulse transmission may produce clinical symptoms and that a central adaptive mechanism to remodulated trains of impulses plays a role in clinical recovery from CNS demyelination.

Acrylamide↗
PubMed1988

Effects of 4-aminopyridine in experimental CNS demyelination.

We studied the effect of systemically administered 4-aminopyridine in a model of CNS demyelination. In five rats with demyelination, slowed conduction velocity through the lesion was partially reversed at dose levels of 5.6 to 7.2 mg/kg. All rats developed convulsion at this dosage, and impaired conduction of high-frequency impulses was unchanged. These findings suggest certain limitations of 4-aminopyridine as a therapeutic agent.

4-Aminopyridine↗
PubMed1988

Monoclonal antibody to the streptococcal preparation OK-432: tissue OK-432 localization and analysis of interaction between OK-432 and macrophages or NK cells in human salivary adenocarcinoma-bearing nude mice given OK-432.

An immunoglobulin M mouse monoclonal antibody (MAb) to the streptococcal preparation OK-432, TS-1, was generated. The TS-1 antigen is a carbohydrate epitope. This antigen is stable upon fixation and embedding in paraffin. The tissue and cellular OK-432 localization in human salivary adenocarcinoma-bearing nude mice given OK-432 intratumorally was examined by various methods according to the immunological procedures using the purified TS-1 MAb. The presence of OK-432 antigen recognized by TS-1 MAb was clearly observed in the tumor as well as the spleen and lung 24 or 48 h after OK-432 administration, whereas transfer of OK-432 from the site of injection to the organs, such as liver and kidney, was rarely seen. The presence of OK-432 antigen in some immunocompetent cells, as defined by Mac-1 antigen or asialo GM1 antigen, was observed by the double-antibody labeling technique in the tumor and spleen from tumor-bearing nude mice. Moreover, interaction between OK-432 and macrophages or natural killer (NK) cells in relation to expression of interferon (IFN) in tumor-bearing nude mice given OK-432 was observed. Consequently, significant increases of Ia-positive or Ia-negative macrophages, NK cells as well as IFN-alpha/beta- or IFN-gamma-positive cells in the tumor and/or spleen were found when compared with those without OK-432 administration.

Adenocarcinoma↗
PubMed1987

Bipolar recording of short-latency somatosensory evoked potentials after median nerve stimulation.

Generators of median short-latency somatosensory evoked potentials were studied with three orthodiagonal pairs of bipolar electrodes. N11 was attributed to the dorsal root and dorsal column volleys. N13 had at least two subcomponents, generator dipoles of which are directed horizontally (N13a) and axially (N13b). N13a was generated in the lower cervical cord. N13b (bipolar) and P14 far-field (noncephalic reference) appeared to originate in the cuneate nucleus or spinocerebellar tracts as well as in the medial lemniscus. Bipolar recordings were useful in localizing cervical cord lesions, which was impossible in conventional monopolar recordings.

Adult↗
PubMed1986

Origin of short-latency somatosensory evoked potentials to median nerve stimulation in the cat. Comparison of the recording montages and effect of laminectomy.

Short-latency somatosensory evoked potentials were recorded from 23 cats with the frontal-neck, scalp-ear and scalp-noncephalic reference montages. In the frontal-neck recordings, four or five components (n9, n11, n13a, n13b and n14) were identified, whereas three components (p15, p18 and p20) were recorded in the scalp-ear leads. The noncephalic reference recordings had four to six components (p9, p10, p11, p13a, p13b and p14). The origin of these components was investigated by recording direct from the attributed generators and examining the effects of lesions. The suggested generators are as follows: n9, p9 and p10-peripheral nerve; n11, p11-dorsal column; n13a-segmental dorsal horn; p13a-spinocerebellar tract; n13b and p13b-cuneate nucleus and caudal part of the medial lemniscus; n14, p14 and p15-rostral part of the medial lemniscus; p18-thalamocortical radiation; p20-primary somatosensory cortex. Components with similar latencies such as n13a and p13a in the frontal-neck and noncephalic reference recordings had different generators. In the noncephalic reference recordings, the axially orientated dipoles, including the potential produced by the spinocerebellar tract (p13a) were clearly detectable, but the transversely orientated dipole of the segmental dorsal horn (n13a) was indistinct. The frontal-neck montage was distorted by the frontal 'reference' electrode active for part of the axially ascending volleys (p13a in some cats and p14), but could pick up the near-field potentials in the segmental dorsal horn (n13a). Desynchronized volleys in fibre tracts such as the spinothalamic tract did not contribute significantly to the potentials recorded from the skin, whereas the synaptic potential in the cuneate nucleus was shown to have a steep onset and open-field distribution with its dipole orientated in part axially, and was recorded in the noncephalic reference montage. The p9 and p11 positivities fused after laminectomy, suggesting that conductance change at the root entry to the bony spinal canal separates these components in the noncephalic reference recording.

Anesthesia↗
PubMed1985

Brainstem auditory evoked potentials in early diagnosis of basilar artery occlusion.

Brainstem auditory evoked potentials (BAEPs) were recorded in the acute and chronic phases of two patients with basilar artery occlusion. BAEPs in the acute phase showed disappearance of the waves before CT evidence of a definite low-density area in the brainstem. In one patient, the waves reappeared in the chronic phase, suggesting the importance of monitoring BAEPs in the acute phase.

Aged↗