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Biomedical subjects

K Fukushima

Publications and source records attributed to K Fukushima.

At least 253 records · Page 14Linked to original sources
PubMed1997

Stability of ocular counterrolling and Listing's plane during static roll-tilts.

PURPOSE: To investigate whether habituation occurs in ocular counterrolling (OCR), how stable shifted Listing's plane is, and what effects visual stimulation and alertness exert on the OCR and on Listing's plane. METHODS: Two monkeys (Macaca fuscata) were engaged in this experiment. A dual scleral search coil method was used for recording three-dimensional eye movements. Spontaneous eye movements were recorded for 2 hours in dark and light, while each monkey was held in different static roll positions (up to +/-34 degrees) with its head fixed. Eye movements were also recorded during the monkeys' drowsy periods in the dark. RESULTS: In alert conditions, OCR gains showed some fluctuations but did not change consistently for 2 hours in seven of seven sessions in the dark and in seven of nine sessions in the light. The OCR gains in the light did not differ from those in the dark. The thickness of shifted Listing's plane during the static roll-tilt was also stable for 2 hours and was within the range of the thickness of Listing's plane in the upright position in the light. During drowsy periods, the thickness of Listing's plane increased, and the gain in OCR decreased. CONCLUSION: Ocular counterrolling shows no habituation for 2 hours of static roll-tilts in the alert monkey. In the same condition, Listing's plane consistently maintains its precision. Visual input does not affect OCR, but alertness is necessary to keep the stability of OCR and Listing's plane.

Adaptation, Ocular↗
PubMed1997

[Mycetoma-forming pulmonary nocardiosis and endobronchial polypoid lesion].

A 46-year-old man was admitted to the hospital for evaluation of a dense infiltrative shadow in the right middle lung field. Bronchoscopic examination revealed a polypoid lesion in the right middle-lobe bronchus (Bb11(5)). Examination of a biopsy specimen showed a lump with many Nocardia asteroides bacteria. The response to chemotherapy, which included sulfomethoxazole, was poor, and therefore a right middle lobectomy was done. Three mycetomas were found inside the ectatic bronchi in the S5 area. Pulmonary Nocardia mycetoma is rare.

Bronchi↗
PubMed1996

Evaluation of three individual glucosyltransferases produced by Streptococcus mutans using monoclonal antibodies.

We previously established murine hybridomas producing a monoclonal antibody monospecific against three glucosyltransferases (I, SI and S) of Streptococcus mutans which contribute to dental caries formation. Here, we developed a new immunochemical technique (cross-dot system) with which individual levels of glucosyltransferases expressed by S. mutans can be evaluated. We also examined glucosyltransferase production and in vitro artificial plaque formation by a reference strain and several clinical isolates of S. mutans. The findings indicate that the levels of glucosyltransferases produced greatly vary with the cells and the culture medium, and that the cells producing high levels of both glucosyltransferase-SI and glucosyltransferase-I enzymes may possess high in vitro artificial plaque forming ability. We suggest that the cross-dot system will be useful for estimating the cariogenic potential of S. mutans isolates.

Antibodies, Monoclonal↗
PubMed1996

Nitric oxide donor SNAP induces apoptosis in smooth muscle cells through cGMP-independent mechanism.

Recent evidence suggests that nitric oxide (NO) may function as a second messenger in the intracellular signal transduction pathways. We explored the possibility that NO was involved in the signal for triggering apoptosis in smooth muscle cells (SMCs). Chemical NO donors induced SMCs apoptosis in a concentration- and time-dependent manner. The membrane-permeable cGMP analogue, dibutyryl-cGMP, did not induce SMCs apoptosis, and the highly selective inhibitor of cGMP-dependent protein kinase, KT5823, was unable to inhibit the induction of NO-induced SMCs apoptosis. Inhibitor of ADP-ribosyltransferase slightly attenuated the induction of SMCs apoptosis by S-nitroso-N-acetyl penicillamine (SNAP). The inhibitor of Na+-H+ antiporter, amiloride, completely inhibited the induction of SMCs apoptosis by SNAP. These results demonstrate for the first time that NO can induce apoptosis in SMCs, suggesting that NO acts as a mediator in the development of atherosclerosis lesion via alterations in the number of SMCs. In addition, the results suggest that NO exert these effects through a pathway that does not involve guanylate cyclase and cGMP-dependent protein kinase.

Amiloride↗
PubMed1996

Extended strictureplasty for multiple short skipped strictures of Crohn's disease.

PURPOSE: We will describe a new procedure for treatment of multiple short strictures involving a short segment of Crohn's disease. METHODS: This procedure involves the following: 1) stay sutures at the mid portion of the two strictures; 2) an antimesenteric longitudinal enterotomy of 12 cm or more; 3) two or three interrupted transmural sutures in the four lateral portions of the two stenoses; 4) a transverse running suture, according to Heineke-Mikulicz-type strictureplasty; and 5) interrupted seromuscular sutures. RESULTS: We performed four such "double Heineke-Mikulicz"-type strictureplasties in three patients with Crohn's disease without postoperative complications. CONCLUSION: This type of double Heineke-Mikulicz-type strictureplasty is suitable for multiple short skipped strictures of Crohn's disease in selected patients.

Adult↗
PubMed1996

Epidural administered buprenorphine in the perioperative period.

PURPOSE: To study the effect of epidural buprenorphine on minimum alveolar concentration (MAC) of volatile anaesthetics, duration of analgesia and respiratory function in the perioperative period. METHODS: One hundred and twenty patients, ASA I-II undergoing gynaecological surgery were randomly divided into three studies. The forty patients in each study were randomly divided into four groups depending on the dosage; Group I (control), Group II (80 micrograms. kg-1 morphine), Group III (4 micrograms. kg-1 buprenorphine), Group IV (8 micrograms. kg-1 buprenorphine). The MAC of halothane was measured following epidural administration of the agents in each group. The duration of analgesia was assessed by the first request for pentazocine. Postoperative analgesic effects were assessed by the total dosage of pentazocine required for the 48 hr after surgery. Respiratory rate (RR), minute volume (MV), and PaCO2 were measured during surgery and the postoperative period. The MAC of halothane was reduced in Group IV (P < 0.01). The duration of analgesia was 10.0 +/- 5.1 hr (Mean +/- SE) in Group I, 37.7 +/- 4.7 hr in Group II, 27.1 +/- 7.1 hr in Group III, and 44.4 +/- 4.1 hr in Group IV. Total dosage of pentazocine was lower in Group IV (P < 0.05) than in the other groups. The decrease of RR, MV and the increase of PaCO2 were observed within 60 min in Group III and IV dose dependently. CONCLUSION: Epidural buprenorphine administered in a dose of 4 or 8 micrograms. kg-1 provides postoperative analgesia that is no less effective than that of morphine.

Adult↗
PubMed1996

Wound infiltration with lidocaine prolongs postoperative analgesia after haemorrhoidectomy with spinal anaesthesia.

PURPOSE: There are few clinical data examining whether sensitization of peripheral nerves contributes to postoperative pain when the entry of noxious impulses to the central nervous system is blocked. We hypothesized that wound infiltration with lidocaine would provide better postoperative analgesia than with normal saline following haemorrhoidectomy with spinal blockade. METHODS: In a randomized, placebo-controlled, blinded study, 168 adults undergoing haemorrhoidectomy were allocated to two groups. In Group L (n = 88) local infiltration was provided with lidocaine 1% and in Group S (n = 80) with normal saline. Following spinal anaesthesia with lidocaine 3%, the surgeon infiltrated 15 ml of either infiltration solution to the surgical area. Postoperative analgesia was obtained by continuous epidural administration of 90 mg eptazocine in normal saline for 48 hr. Supplemental analgesics were given on request. Postoperative pain control was assessed at rest and during coughing with a 10 cm VAS on the 1st, 2nd, and 3rd postoperative days (POD). RESULTS: The VAS scores at rest in Group L were lower than those in Group S throughout the postoperative period. During coughing, VAS scores in Group S were increased on the 3rd postoperative day, while those in Group L remained constant (4.42 +/- 0.27 vs 3.14 +/- 0.28, P < 0.05). Fewer patients in Group L than in Group S required supplemental analgesics. CONCLUSION: Preoperative lidocaine infiltration to the surgical area provided prolonged postoperative analgesia in patients receiving haemorrhoidectomy with spinal anaesthesia.

Adult↗
PubMed1996

Simple-spike activity of floccular Purkinje cells responding to sinusoidal vertical rotation and optokinetic stimuli in alert cats.

To understand how the cerebellar flocculus is involved in the processing of semicircular canal signals in the vertical vestibulo-ocular reflex (VOR), we analyzed the simple-spike activity of floccular Purkinje (P) cells that was modulated by sinusoidal pitch rotation, and then analyzed their activity during presentation of sinusoidal vertical optokinetic stimuli in alert, head-fixed cats. The great majority of P cells also responded to optokinetic stimuli with peak discharge near peak stimulus velocity. Eighty percent of P cells that responded to both pitch and optokinetic stimuli showed increased activity when the directions of the resultant eye movements were the same. During rapid modification of the VOR induced by visual pattern movement, modulation amplitudes of the cells tested increased together with the eye velocity increase. Maximal activation directions of these cells studied during vertical rotation in many planes were near the vertical canal planes, similar to those in our previous studies. The remaining 20% of P cells showed increased discharge for the same direction of stimulus movement. These results suggest that the activity of the majority of pitch-responding P cells contains, at least partly, a vertical eye velocity component during presentation of vestibular or optokinetic stimuli in addition to canal inputs during pitch rotation.

Animals↗
PubMed1996

Cross axis vestibulo-ocular reflex induced by pursuit training in alert monkeys.

We examined the effect of conflicting vestibular and smooth pursuit information on the vestibulo-ocular reflex (VOR) in alert monkeys. Sinusoidal whole body rotation was applied either in the pitch or yaw plane while presenting a target spot that moved orthogonally to the rotation plane. The monkeys were rewarded for tracking the spot and eye movements induced by rotation alone were examined every 15-30 min in complete darkness. Orthogonal eye movement responses to rotation were not observed before training but appeared after about 30 min of training. The gains (eye/chair) of the orthogonal component increased up to 0.2 after 1-2 h and were largest at the training frequency and approximately in phase with the stimulus; phase advanced at lower frequencies and lagged at higher frequencies. Amplitude tuning was also demonstrated when examined using different amplitudes at a constant frequency after training. Two hours of training to fixate an earth-stationary spot projected onto a patterned visual background that moved orthogonally to the rotation plane during rotation, did not induce a cross axis response. These results indicate that pursuit training during VOR is effective in inducing cross-axis eye movement responses that are tuned to the metrics of the training stimulus.

Adaptation, Physiological↗
PubMed1996

Adaptive changes in human smooth pursuit eye movement.

Adaptive changes in initial eye velocity of pursuit eye movement were examined in nine normal subjects using a target that moved in a multiple ramp fashion. Significant changes in initial eye velocity occurred rapidly after training in six of the subjects. The magnitude and direction of the induced changes were a function of the training conditions. Adaptive changes started 100-200 ms after onset of pursuit eye movement (usually 140 ms), suggesting that the late (but not early) component of initial eye velocity was under adaptive control by our training paradigms.

Adaptation, Physiological↗
PubMed1996

Genotype analysis of the CYP2C19 gene in the Japanese population.

A polymorphic CYP2C19 gene was analyzed in 233 Japanese subjects, including 63 with Parkinson's disease, 92 with chronic liver diseases (35 chronic hepatitis, 19 liver cirrhosis, 16 hepatocellular carcinoma, 10 primary biliary cirrhosis and 12 autoimmune hepatitis), 14 with lung cancer (squamous cell carcinoma) and 64 healthy subjects to determine the genotype distributions of the CYP2C19 gene and to investigate its involvement in the diseases. Among Japanese healthy subjects 14.1% are predicted to be poor metabolizers (PM) of mephenytoin. The frequencies of the m1 and the m2 mutations of the CYP2C19 gene in the healthy subjects were 21.9% and 11.7%, respectively. Though the number of patients was small, patients with lung cancer (squamous cell carcinoma) are believed to have reduced enzyme activities of CYP2C19.

Aryl Hydrocarbon Hydroxylases↗
PubMed1996

Further evidence for the specific involvement of the flocculus in the vertical vestibulo-ocular reflex (VOR).

We examined the simple-spike activity of floccular Purkinje (P) cells during sinusoidal pitch rotation and vertical optokinetic stimuli in alert, head-fixed cats. The great majority of pitch-responding P cells also responded to optokinetic stimuli with increased activity when the directions of the resultant eye movements were the same. During rapid modification of the VOR induced by visual pattern movement, modulation amplitudes of the cells tested increased together with the eye velocity increase. Maximal activation directions of these cells studied during vertical rotation in many planes were near the vertical canal planes. These results suggest that the activity of the majority of pitch-responding P cells contains a vertical eye velocity component during vestibular or optokinetic stimuli in addition to canal inputs during pitch rotation.

Animals↗
PubMed1996

Pitfalls in cytokine analysis in inflammatory bowel disease.

Analysis of cytokine production and function is an indispensable tool to study Crohn's disease and ulcerative colitis. This analysis has generated a tremendous amount of data, but a clear interpretation of results has been hampered by limited attention paid to several patient- and sample-related pitfalls. These include: clinical parameters; the relative value of circulating vs. intestinal cytokine levels; the selection of tissue specimens and their processing method; the specific cellular source of each cytokine; the effect of cytokine inducers; and the technique utilized to obtain qualitative or quantitative data on cytokine protein or mRNA. Once all of these crucial variables are taken into proper perspective, a better understanding will emerge of the true role of cytokines in the pathogenesis of inflammatory bowel disease.

Colitis, Ulcerative↗
PubMed1996

A single point mutation of hamster aminoacyl-tRNA synthetase causes apoptosis by deprivation of cognate amino acid residue.

BACKGROUND: We have isolated a series of temperature-sensitive mutants for cell-proliferation from the BHK21 cell line derived from the golden hamster (Nishimoto & Basilico 1978; Nishimoto et al. 1982). Using these mutants as a recipient of DNA-mediated gene transfer, we have been cloning human genes which complement these ts mutants. RESULTS: Cultures of tsBN269 cells, a temperature-sensitive mutant of the BHK21 cell line, underwent apoptosis at 39.5 degrees C, a nonpermissive temperature. The gene complementing the tsBN269 cells was cloned and found to encode lysyl-tRNA synthetase. Indeed, tsBN269 cells were found to have a single cytosine to a thymine point mutation at the first nucleotide of codon 542 in hamster lysyl-tRNA synthetases. Due to this mutation, the activity of lysyl-tRNA synthetase was reduced--even at 33.5 degrees C, a permissive temperature. Consistent with these findings, while supplementation with lysine permitted tsBN269 cells to grow at a nonpermissive temperature, the deprivation of lysine caused apoptosis in tsBN269 cells, even at 33.5 degrees C. Cycloheximide inhibited the apoptosis caused by lysine starvation at 33.5 degrees C, but not at 39.5 degrees C. We also found that another hamster temperature-sensitive mutant, tsBN250, which is defective in histidyl-tRNA synthetase, entered apoptosis with the deprivation of histidine. CONCLUSION: Our data suggested that the defect in aminoacyl-tRNA synthetase turned on the cascade of apoptosis that was already present in the cells.

Amino Acid Sequence↗
PubMed1996

A hamster temperature-sensitive G1 mutant, tsBN250 has a single point mutation in histidyl-tRNA synthetase that inhibits an accumulation of cyclin D1.

BACKGROUND: We have previously isolated a series of temperature-sensitive mutants for cell-proliferation from the BHK21 cell line, derived from the golden hamster. These mutants proliferate at 33.5 degrees C, the permissive temperature, but not at 39.5 degrees C the restrictive temperature. Using DNA-mediated gene transfer, human genes complementing these ts mutants were cloned. RESULTS: At 39.5 degrees C the tsBN250 cell line, a temperature-sensitive mutant of the BHK21 cell line, had a defect in the G1 phase, but not in the S phase. The human gene complementing tsBN250 cells was found to encode histidyl-tRNA synthetase. Indeed, the tsBN250 cell line had a single base change--guanine to adenine at the second position of the 362nd codon of hamster histidyl-tRNA-synthetase, converting arginine to histidine. Following release from serum starvation, cyclin E, but not cyclin D1, was accumulated, while, at 39.5 degrees C, the mRNA of cyclin D1 was normally expressed in tsBN250 cells. A similar inhibition of cyclin D1 accumulation was observed in another ts mutant, tsBN269, which has a single point mutation in lysyl-tRNA synthetase. Overexpression of cyclin D1 enabled tsBN250 cells to enter the S phase. CONCLUSION: tsBN250 cells have a single point mutation in histidyl tRNA synthetase that causes a loss of histidyl-tRNA synthetase activity which in turn reduces the content of cyclin D1, but not of cyclin E, thereby resulting in G1 arrest.

Amino Acid Sequence↗
PubMed1996

A gene for autosomal dominant late-onset progressive non-syndromic hearing loss, DFNA10, maps to chromosome 6.

Late-onset non-syndromic hearing impairment is the most common type of neurological dysfunction in the elderly. It can be either acquired or inherited, although the relative impact of heredity on this type of loss is not known. To date, nine different genes have been localized, but none has been cloned. Using an extended American family in which a gene for autosomal dominant late-onset non-syndromic hearing impairment is segregating, we have identified a new locus, DFNA10, on chromosome 6.

Chromosome Mapping↗