Biomedical subjects

T Oikawa

Publications and source records attributed to T Oikawa.

At least 199 records · Page 11Linked to original sources

PubMed1990

Ultrastructural evidence for an association between an oviductal glycoprotein and the zona pellucida of the golden hamster egg.

The ultrastructural localization of an oviductal glycoprotein, designated ZP-0 in golden hamster oviductal eggs, was investigated by immunolabeling methods using a monoclonal antibody (C11E8). Immunofluorescence staining showed that C11E8 specifically reacted with the zona pellucida of the oviductal egg but not the ovarian egg. In an immunoelectron microscopic study applying the protein-A gold technique, gold particles were distributed throughout the zona pellucida of the oviductal eggs and were also associated with the perivitelline matrix. Structures within the eggs and cumulus cells did not react with C11E8. Quantitative evaluations of the degree of labeling demonstrated that a large number of gold particles was bound to the zone pellucida, especially in the middle layer. Moreover, in bovine testicular hyaluronidase-treated eggs the density of labeling decreased only in the outer third of the zona pellucida. These results show that ZP-0 to the was associated with the zona pellucida and perivitelline matrix of the golden hamster egg after ovulation and suggest that there are topographical differences in the binding activity of ZP-0 to the zona pellucida. In addition, the decrease in labeling density of ZP-O induced by hyaluronidase appears to be related to changes in the properties of the outer layer of the zona pellucida.

Animals↗

PubMed1990

Mono- and disynaptic excitatory inputs from the superior colliculus to vertical saccade-related neurons in the cat Forel's field H.

Excitatory inputs to neurons in the Forel's field H (FFH) related to visually induced vertical saccades from the ipsilateral superior colliculus (SC) were investigated in chronically prepared alert cats. By stimulation of the deep or intermediate layer of the SC, upward augmenting neurons (ANs) and one long-lead downward burst neuron (BN) were found to be activated monosynaptically, while medium-lead BNs were activated disynaptically. The monosynaptically activated neurons were not antidromically activated from the oculomotor nucleus, whereas disynaptically activated neurons were also activated antidromically from the inferior rectus subdivision of the nucleus. These results suggest that an excitatory input to the FFH from the SC for inducing vertical saccades of visual origin first reaches upward ANs and/or long-lead downward BNs in the FFH, which in turn drive medium-lead BNs in the same area synapsing with motoneurons related to vertical eye movements.

Animals↗

PubMed1990

Immunological regression of metastatic cancer in the liver as a result of "in vivo xenogenization".

We attempted to induce the regression of liver metastatic tumor cells in vivo by the administration to rats of Friend leukemia virus (FV) (in vivo xenogenization). The virus which was used in this experiment, FV, is highly immunogenic and does not normally cause disease in an adult rat. At first, we induced a FV viremia in tumor bearing rats in order to deliver the virus to the site of the tumor cells. FV viremia was induced by injecting 60 mg/kg cyclophosphamide (CY) i.v. after the administration of FV, and by transferring syngeneic bone marrow cells so that FV would be able to infect them and then replicate. In order that the tumor cells which were infected with virus should regress, it was necessary to break down their tolerance to FV antigens. As adoptive immunotherapy we therefore, transferred syngeneic spleen cells from rats which had been immunized with FV to tumor bearing rats. The result of this experiment was that these tumor bearing rats infected with FV which had received either normal syngeneic spleen cells or no spleen cells as controls died from liver metastasis (8 out of 9 rats (89%) and 15 out of 17 (88%) respectively). On the other hand, only 4 out of the 15 (27%) tumor bearing rats which were infected with FV and which received FV-immune spleen cells died from liver metastasis. These sets of data indicate that the in vivo xenogenization of tumor cells are indeed able to induce the regression of metastatic tumor cells.

Animals↗

PubMed1990

Immunological properties of type IV collagen from mouse kidney.

Some immunological properties of mouse kidney type IV collagen (MKIVC) were investigated. In enzyme-linked immunosorbent assay (ELISA), rabbit anti-MKIVC antiserum reacted strongly with MKIVC but not at all with type I collagen or laminin of mouse origin. Thus, the purified MKIVC preparation was not contaminated with detectable amounts of other constituents of the extracellular matrix and the basement membrane including interstitial collagens, as suggested previously (T. Oikawa et al., Chem. Pharm. Bull., 34, 789 (1986)). In ELISA inhibition assay, human kidney type IV collagen (HKIVC) only partially inhibited the binding of MKIVC to anti-MKIVC antiserum. Similarly, HKIVC showed a far weaker binding capacity to the antiserum compared to MKIVC in ELISA direct binding assay. After the anti-MKIVC antiserum was absorbed with acetone powder of human kidney, the resulting antiserum still possessed a considerable binding activity to MKIVC but did not react with HKIVC. In accord with these findings, anti-MKIVC antiserum immunostained both mouse and human renal basement membranes, while it stained the former but not the latter after being absorbed with human kidney. Taken together, these results suggest that MKIVC possesses at least two antigenic determinants; one but not the other cross-reacts with human kidney basement membrane collagen.

Animals↗

PubMed1990

Inhibition of angiogenesis by bleomycin and its copper complex.

The effects of bleomycin (BLM) and its copper complex on embryonic angiogenesis were studied in the chorioallantoic membranes of 4.5-day-old chick embryos. Copper-free BLM inhibited embryonic angiogenesis in a dose-dependent manner, with activity detectable at 1 ng/egg and maximal at 1000 ng/egg. Also, treatment with copper-BLM complex dose-dependently caused inhibition of embryonic angiogenesis in a lower dose range. Since tumor growth is believed to depend on angiogenesis, the present results may indicate that the antiangiogenic activity of BLM is, at least in part, implicated in the antitumor activity of the drug.

Animals↗

PubMed1990

[Directional hearing of unilaterally hearing impaired--especially sense of sound direction in monaural hearing impairment and monaural deafness].

I. OBJECTIVE. The present study was undertaken in order to determine the onset of monaural deafness, especially whether it is congenital or acquired, making an investigation into the sense of sound direction in monaural hearing impairment and monaural deafness and comparing them between hearing-impaired patients and normal hearers. II. SUBJECTS. This study was carried out on 26 patients with monaural hearing impairment, 22 patients with monaural deafness and 10 normal hearers. III. METHODS. A circle with a radius of 1.3m was drawn around a fixed patient's position in a sound proof room, and the circle was divided into 16 directions at an equal angle of 22.5 degrees. A blindfolded hearer was instructed to listen to a speaker for white noise of 60dB (A) for one second and verbally answer in which direction he heard the noise. The normal hearers were tested in 4-, 8-, and 16-directions, and the hearing-impaired patients were tested in only 8-directions. IV. RESULTS. 1. Normal Hearers The rate of correct answers decreased with increasing directions of sound. The incorrect answers in 4-direction testing were only confusion between forward and backward directions, and similar incorrect answers were made in 8- and 16-direction testing. All other incorrect answers were errors of less than 45 degrees. 2. Monaurally Hearing-impaired Patients The rate of correct answers on the whole was low. There was such a relationship between the rate of correct answers and the mean hearing level of patients that the total rate of correct answers decreased with increasing hearing impairment. This correlation was statistically significant, and there was a still more significant correlation between the degree of hearing impairment and the rate of correct answers as to the right and left directions. Incorrect answers were errors of 90 degrees or less on the healthy side, while errors were made for all directions on the affected side. 3. Monaurally Deaf Patients The rate of correct answers was by far lower on the affected side. Whereas many errors were within 45 degrees on the healthy side, errors were made for all directions on the affected side. Judging from the onset of hearing loss, the monaurally deaf patients were divided into a group of 8 patients who obviously had sudden acquired deafness and a group of 9 patients who were presumed to have congenital monaural deafness. The mean rate of correct answers of the former group was superior to the latter group's, particularly on the effected side.

Adolescent↗

PubMed1990

[Pulse oximetry for noninvasive oxygen monitoring during dental treatment in children with congenital heart disease].

Children with congenital heart disease (CHD) are prone to present abrupt changes in cardiovascular functions which cause hypoxic spells or acute heart failure, so that oxygen monitoring during dental treatment is of great importance in cyanotic CHD patients. Monitoring of arterial oxygen saturation (SpO2) by pulse oximetry has several advantages, including rapid response time, freedom from skin injury, self-calibration and continuous readout of the SpO2 value. In these studies, SpO2 was measured in 68 pediatric patients (55 were CHD children and 13 were normal children) during dental treatment at the Pediatric Dentistry, Hokkaido University Dental Hospital. In all of the normal patients, SpO2 did not desaturate less than 95%. On the other hand, SpO2 ranged from 56% to 98% in CHD patients, and in 22% (n = 12) of these, SpO2 desaturated below 80%. All of the SpO2 less than 80% patients had been diagnosed as cyanotic CHD. Classification of CHD cases (n = 144, the total number of measurements) on the pattern of the SpO2 variation revealed that in 11% (n = 16) of the CHD cases, SpO2 decreased during dental treatment. Twelve of these 16 cases could not readily accept dental treatment. We suggest that behavior management is the most important factor in CHD patients for keeping SpO2 stable. Motion artifact of the SpO2 value, which was easily evoked when a patient bent his elbow or shook his finger, often made the pulse oximetry useless. In our studies, the SpO2 value sometimes became inaccurate in fearful infants or handicapped patients. Pulse waveform displayed on the front panel of pulse oximetry was useful to identify the motion artifact. We conclude that pulse oximetry is an appropriate apparatus for continuous arterial oxygen monitoring in pediatric patients during dental treatment as far as motion artifact is effectively eliminated.

Artifacts↗

PubMed1990

[Repression of rearranged c-myc expression in murine cell hybrids].

In hybrids SBW I and SBW II between S194 mouse plasmacytoma and BW5147 mouse T-cell lymphoma, enhanced expression of the rearranged c-myc mRNA of heterogeneous sizes (1.8-2.4 kb) in S194 was markedly downregulated but expression of the non-rearranged c-myc of 2.4 kb in BW5147 was not. Treatment of SBW I hybrid cells with cycloheximide augmented non-rearranged c-myc expression 2-4-fold but did not release the downregulated expression of the rearranged c-myc. Nuclear run-on assay showed that the high level of c-myc transcripts in S194 cells declined in SBW I cells comparable to the level in BW5147 cells. The results suggest that the downregulation of the rearranged c-myc in SBW I hybrid cells was at a transcriptional level rather than a posttranscriptional level. Methylation patterns of the rearranged c-myc in SBW I cells was the same as S194 cells. Treatment of the SBW I cells with 5-azacytidine, TPA or forskolin did not release the downregulated expression of the rearranged c-myc, suggesting no causative involvement of DNA methylation or protein phosphorylation in the downregulation. Higher DNase I sensitivity of the rearranged c-myc in S194 cells decreased to a similar extent to that of the non-rearranged c-myc after cell fusion with BW5147 cells. All these results suggest that expression of the rearranged c-myc was downregulated at the level of transcription in murine cell hybrids between a plasmacytoma and a T-cell lymphoma probably by changing the chromatin configuration around the gene from the open to the closed state.

Animals↗

PubMed1990

Nodular glomerulosclerosis in a patient showing impaired glucose tolerance.

We report a case showing typical diabetic nodular glomerulosclerosis without retinopathy or other apparent clinical findings of DM except for impaired glucose tolerance. The 57-year-old man had a family history but no personal history of DM. In an extensive examination for DM, the results of funduscopy, daily profile of serum glucose and hemoglobin Alc were entirely within normal limits. However, the oral glucose tolerance test was abnormal. A renal biopsy showed typical nodular lesions (Kimmelstiel-Wilson's lesions). Previously, the interesting feature of transient proteinuria had been recognized. Although hypocellular nodular lesions by light microscopy are characteristic of diabetic nephropathy, renal amyloidosis, carbon disulfide intoxication, multiple myeloma and light chain disease, we concluded that the present lesions had resulted from diabetic nephropathy based on the family history, patient history, impaired glucose tolerance, immunofluorescent findings and electron microscopic observations.

Diabetic Nephropathies↗

PubMed1990

[Antibacterial activity of norfloxacin on methicillin-resistant Staphylococcus aureus. Comparison with oral antibacterial agents].

Minimum inhibitory concentrations (MIC) of norfloxacin (NFLX) to 133 strains of methicillin-resistant Staphylococcus aureus (MRSA) isolated from clinical patients were investigated and compared with those of minocycline (MINO), erythromycin (EM), amoxicillin (AMPC), cefaclor (CCL) and fosfomycin (FOM). MIC90 of these drugs were 3.13 micrograms/ml with NFLX, 0.39 micrograms/ml with MINO, greater than 100 micrograms/ml with EM, 50 micrograms/ml with AMPC, greater than 100 micrograms/ml with CCL and greater than 100 micrograms/ml with CCL and greater than 100 micrograms/ml with FOM. MIC distribution patterns with 2 peaks were recognized with EM and FOM. Of 55 strains resistant to all of EM, AMPC, CCL and FOM, 50 and 54 strains were well susceptible to NFLX and MINO, respectively. The present investigation demonstrated relatively potent antibiotic effect of NFLX against MRSA. Considering the safety of NFLX to children which have been confirmed and reported separately, it can be concluded that NFLX is a useful oral antimicrobial drug in the treatment of children with MRSA infections.

Administration, Oral↗

PubMed1990

[Pharmacokinetics and clinical safety of aztreonam in neonates].

Clinical pharmacology and safety of aztreonam (AZT) in the neonatal period were investigated. The results obtained are summarized as follows. 1. Serum concentrations of AZT at 30 minutes after administration of 10 mg/kg were 22.1-32.2 micrograms/ml and those of 20 mg/kg 22.5-75.9 micrograms/ml. 2. Serum half-lives of AZT were 3.5-6.6 hours in 0-3 day-old neonates, and 2.0-4.0 hours in neonates 4 day-old or older. 3. A dose response was evident between the 10 mg/kg administration group and the 20 mg/kg group. 4. Urinary recovery rates of AZT in the first 6 hours after administration ranged between 17.8 and 69.9%. 5. No clinical side effects were observed in the administration of AZT alone (6 cases), or in combination with ampicillin (9 cases). Thrombocytosis was observed in 1 case as an abnormal laboratory finding, but it returned to normal within 1 week after the completion of AZT administration. 6. AZT had a potent antimicrobial activity against Gram-negative aerobes and hardly induced beta-lactamase. Furthermore, side effects were not observed in this study. Therefore, AZT is considered to be useful for the treatment of urinary tract infections and other serious infections caused by Gram-negative pathogens even in the neonatal period.

Age Factors↗

PubMed1990

[Pharmacokinetic and clinical studies on aztreonam in neonates and premature infants].

Aztreonam (AZT) was studied for its pharmacokinetics, clinical effect and effect on intestinal bacterial flora in neonates, and the results obtained are summarized as follows: 1. Serum concentrations of AZT upon intravenous administration of 20 mg/kg were 38.6 micrograms/ml in 30 minutes, 30.6 micrograms/ml in 1 hour and 13.6 micrograms/ml in 6 hours. The T 1/2 was 3.73 hours. Ampicillin (ABPC) 25 mg/kg was concurrently used with AZT in 2 cases and serum concentrations of AZT in these 2 cases were 40.3 and 36.9 micrograms/ml in 30 minutes, 35.7 and 32.6 micrograms/ml in 1 hour, and 13.1 and 10.2 micrograms/ml in 6 hours, respectively. T 1/2's were 3.32 and 2.91 hours, respectively, and no interaction between the 2 drugs was observed. 2. AZT was administered to 21 neonates between 0 and 83 days of age and ABPC was concurrently administered to 18 of the cases. Clinical evaluation was made in 14 cases, where AZT was remarkably effective in 7 cases, effective in 6 cases and not effective in 1 case. Of the 21 cases, 1 case of diarrhea, 1 case each of eosinophilia, an increase in platelets, an increase in platelets and an elevation of GOT and a decrease in platelets were recorded. 3. With respect to effects of AZT on intestinal bacterial flora, fecal concentrations of AZT upon its single administration to 2 cases were low suggesting, there was little effect on the intestinal flora. Some effect on anaerobes, however, was recognized in 4 cases in which ABPC was concurrently used.

Ampicillin↗

PubMed1989

A highly potent antiangiogenic activity of retinoids.

Four retinoids, i.e. retinol (vitamin A), retinoic acid, retinyl acetate and synthetic chalcone carboxylic acid (Ch 55), were examined for their effects on embryonic angiogenesis using 4.5-day chorioallantoic membranes of chick embryo. The effects of these retinoids were compared with that of antibiotic herbimycin A, which was the most powerful inhibitor of the angiogenesis reported previously. The four retinoids strongly inhibited embryonic angiogenesis; the order of inhibitory activity was Ch 55 greater than retinoic acid greater than herbimycin A greater than retinyl acetate based on the dose required for the half-maximal inhibitory effect. The present results suggest that retinoids are effective inhibitors of angiogenesis, and can be applied for the management of certain diseases accompanied by aberrant angiogenesis, particularly that which occurs during progressive growth of solid tumors.

Animals↗

PubMed1989

Medroxyprogesterone acetate, an anti-cancer and anti-angiogenic steroid, inhibits the plasminogen activator in bovine endothelial cells.

Medroxyprogesterone acetate (MPA) is an anti-cancer drug for mammary carcinomas and an angiostatic steroid. The effects of MPA on the growth and plasminogen activator (PA) activity of bovine endothelial cells were investigated to elucidate the inhibitory mechanism observed in angiogenesis. MPA did not suppress the growth of capillary endothelial cells, even at high concentrations. On the other hand, in bovine endothelial cells of 3 types (adrenal cortical capillary, aortic and pulmonary artery endothelial cells), MPA inhibited extracellular and cell-associated activity of PA, which might be a protease involved in the neovascular response. MPA also greatly inhibited the high level of PA induced by basic fibroblast growth factor (FGF). The same result was obtained when PA production was induced by 4 beta-phorbol-12-myristate-13-acetate (PMA) in endothelial cells. These findings suggest that one of the points of inhibitory action of MPA in the process of angiogenesis may be the suppression of PA activity, and that inhibition of this protease might be useful for reduction of tumorigenic or excessive angiogenesis in vivo.

Animals↗

PubMed1989

Direct inhibitory synaptic connections of pontine omnipause neurons with burst neurons in Forel's field H related to vertical saccades in the cat.

This study investigated synaptic connections of omnipause neurons (OPNs) in the midline pontine tegmentum with medium-lead burst neurons (BNs) in Forel's field H (FFH), using the spike-triggered averaging technique in chronically prepared alert cats. OPNs were identified behaviorally by tonic firing during the intersaccadic period, whereas medium-lead BNs were identified by spike bursts during upward or downward saccades. A positive shift of field potential in the BN area, associated with suppression of the BNs' bursts, was observed during tonic firing of OPNs and during microstimulation in the OPN area. Averaging of BN area field potentials triggered by spikes of single OPNs on both sides, which were antidromically evoked from the BN area, revealed positive waves with monosynaptic latencies. These results strongly suggest that OPNs on both sides make direct inhibitory synaptic connections with vertical eye movement-related medium-lead BNs in the FFH.

Action Potentials↗

PubMed1989

An electrophysiologically defined trigemino-reticulo-facial pathway related to the blink reflex in the cat.

This study examines the direct projection of neurons in the pontomedullary reticular formation (RF) to the dorsal division of the facial nucleus (FN), where the orbicularis oculi motoneuron pool is located, and the nature of synaptic inputs to the RF neurons from the supraorbital branch of the trigeminal nerve (SON), using electrophysiological techniques in anesthetized cats. A large number of the RF neurons directly projected to the ipsilateral FN dorsal division, and some of these neurons issued axon branches probably terminating on motoneurons in the division. Many of the RF neurons projecting to the dorsal division were synaptically activated by ipsilateral SON stimulation. Most latencies of their activation were between the latencies of the early and late blink reflex responses, and the remaining latencies were shorter than those of the early response. These results suggest that the RF neurons mediate both the early and the late blink reflex responses, but mainly the late response, as premotor relay neurons.

Action Potentials↗

PubMed1989

Differentiation of the golden hamster oviduct epithelial cells during postnatal development: an electron microscopic study.

The ultrastructural changes in the process of differentiation of the epithelial cells of the golden hamster oviduct during postnatal development were investigated by means of electron microscopy. In the epithelium of the ampulla of the neonatal oviducts, no differentiated ciliated cells or secretory cells were identified. In these undifferentiated cells, free ribosomes were well developed, but rough endoplasmic reticulum (RER) and the Golgi apparatus were undeveloped. Cells undergoing ciliogenesis were first identified at 3.5 days after birth, and some ciliated cells appeared at 4.5 days. In the nonciliated cells, marked changes in the organelles were observed at this time. Subsequently, some nonciliated cells containing well-developed RER and Golgi apparatus were observed at 9.5 to 10.5 days after birth, and a few mature secretory cells were observed at 10.5 days. An increase in secretory granules occurred in the secretory cells at 12.5-15.5 days after birth. Many fully mature ciliated and secretory cells were observed at 15.5 days after birth. After 20.5 days after birth, the epithelium was identical with that of the adult golden hamster. Quantitative data indicated that the differentiation of ciliated cells began earlier and took place over a more extended period of time than did that of the secretory cells in the golden hamster oviduct during postnatal development.

Animals↗

PubMed1989

Reduced DNase I sensitivity of the rearranged c-myc gene in somatic cell hybrids between murine plasmacytoma cells and fibroblasts.

In mouse plasmacytoma (MPC) S194, the rearranged c-myc gene was much more sensitive to DNase I digestion than the nonrearranged gene. The sensitivity of the rearranged c-myc was markedly reduced to the same extent as that of the nonrearranged one in hybrids between the MPC cells and the fibroblasts, but not in a hybrid between the MPC and the spleen cells. These results suggest that trans-acting factors in fibroblasts alter the DNase I-sensitive structure of the rearranged c-myc gene.

Animals↗