Biomedical subjects

N Sugano

Publications and source records attributed to N Sugano.

At least 127 records · Page 7Linked to original sources

PubMed1992

Experimental steroid-induced osteonecrosis in adult rabbits with hypersensitivity vasculitis.

Osteonecrosis (ON) was experimentally induced in rabbits by employing a combined protocol of hypersensitivity vasculitis and administration of high-dose corticosteroids. Thirty-five adult rabbits were used: five were injected twice with horse serum (Group A), five were injected three times with methylprednisolone acetate (Group B), 20 were treated with a combination of horse serum and methylprednisolone acetate (Group C), and five were used as a control (Group D). Both femurs of each rabbit were obtained one to five weeks after the final treatment and were histologically examined. There was no evidence of ON in Groups A, B, and D, whereas vasculitis was prominent in the femurs of Group A rabbits. In Group C, 14 of 20 specimens (70%) showed histologic evidence of ON in the femoral metaphysis: seven showed marrow necrosis and seven marrow and trabecular necrosis. Intramedullary hemorrhage was detected in eight animals. All specimens that showed ON or marrow necrosis revealed arteriopathy (i.e., severe damage to the vascular wall structure of arterioles). These findings were similar to those observed in early ON of clinical materials. The authors conclude that arteriopathy plays an important role in the pathogenesis of ON.

Animals↗

PubMed1992

The fate of nontraumatic avascular necrosis of the femoral head. A radiologic classification to formulate prognosis.

One hundred fifteen hips in 87 patients with non-traumatic avascular necrosis of the femoral head (ANFH) (men, 54; women, 33) (steroid induced, 49; alcoholic, 21; idiopathic, 17) were radiologically classified into six distinct types (Types 1A, 1B, 1C, 2, 3A, and 3B) based on the following: (1) the size and location of the necrotic area in relation to the weight-bearing surface of the acetabulum as seen on anteroposterior views in the standing position and (2) initial roentgenographic abnormalities. The natural course of the disorder in each group were observed for more than two years (range, two to 18 years; mean, five years). Of the 79 hips without collapse of the femoral heads (Stage II) at the beginning of follow-up evaluation, 42 femoral heads subsequently collapsed. These collapses took place predominantly in cases involving Types 1C, 2, and 3B. Conversely, the incidence of collapse was significantly low in the other groups (Types 1A, 1B, and 3A). Collapse of the femoral head occurred in 78 femoral heads of 115. The incidences of collapse by group was 0% for Type 1A, 19% for Type 1B, 94% for Type 1C, 100% for Type 2, 12% for Type 3A, and 100% for Type 3B. These data indicate that this radiologic classification of necrosed femoral heads is useful for evaluation of the risk of collapse or for prognosis of the affected hip joints as well as for choosing an appropriate treatment modality, either conservative or surgical, during the early stages of ANFH.

Female↗

PubMed1991

A nuclease from rat-liver nuclei with endo- and exonucleolytic activity.

An Mg2(+)-dependent endonuclease endogenous to rat-liver nuclei had an exonuclease activity for single-stranded DNA, but not for duplex DNA. The activity was about twice as high in the 3'----5' direction as in the 5'----3' direction. The products by 3'----5' activity were mononucleotides alone. The 5'----3' activity released mononucleotides as main products and small amounts of di-, tri-, tetra- and oligonucleotides. Another major endonuclease endogenous to the nuclei, a Ca2+/Mg2(+)-dependent endonuclease, did not have such exonuclease activities.

Animals↗

PubMed1991

Bending of a highly repetitive component in rat nuclear DNA.

A highly repetitive component in rat nuclear DNA was isolated by HindIII digestion and cloned. A 370-bp cloned component was highly AT-rich (68.3%) in about one third of the region from the 3'-terminus and showed an anomalously slow gel electrophoretic mobility (k-factor = 1.19). These results indicated that a sequence-directed bending of the helix axis occurs in the component. Accordingly, a subclone containing a tandem dimer of the component was isolated and subjected to a circular permutation analysis for exploring the bend center (1). In consequence, the center was shown to be present in the sequence ranging from position near 270 to the 3'-terminus and estimated to be located around position 340.

Animals↗

PubMed1990

Base sequences of highly repetitive components in nuclear DNAs from rat liver and rat-ascites hepatoma.

A 370-bp highly repetitive component in each of the nuclear DNAs from rat liver (RL) and rat-ascites hepatoma (AH) was isolated by HindIII digestion and cloned in pUC9. Ten of the resulting clones were arbitrarily selected and sequenced. Heterogeneity of size was found in 7 of the RL clones (366-369 bp), but in only 2 of the AH clones (369 bp). The sequence homology was 64.6% among the RL clones; 80.3% among the AH clones. The base compositions were AT-rich, ranging from 61.1% to 64.7%. Many A and/or T runs consisting of 2-5 bases were interspersed throughout each sequence. The restriction sites reported previously, EcoRI, HaeIII, HindIII, HinfI and HphI sites, were confirmed in almost all of the clones. In the present experiment, 12 kinds of the sites were further found in both RL and AH clones.

Animals↗

PubMed1989

Purification and properties of an endonuclease endogenous to rat-liver nuclei.

An endonuclease endogenous to rat-liver nuclei has been purified by a series of chromatographic procedures and finally by isoelectric focusing (IEF) electrophoresis. The nuclease fraction prepared by the IEF electrophoresis (IEF fraction) showed a pI value of 5.7 and migrated as a single band to a molecular weight position of 46,000 on an SDS-polyacrylamide gel. The activity for single-stranded DNA was enhanced by 10 mM MgCl2 and/or by 5-15 mM MgCl2 in the presence of 2 mM CaCl2 (an optimum pH, 7.0), but was lowered by CaCl2 alone and inhibited strongly by ZnCl2 or MnCl2. The activity for duplex DNA was rather low, although an optimum condition was 10 mM MgCl2. In fact, even under this condition, the activity was about 40% lower than that for single-stranded DNA. Moreover, the IEF fraction formed single-strand nicks much more rapidly than double-strand cuts in pBR322 DNA, and preferentially produced deoxyadenosine 5'-monophosphate termini in the DNA. In addition, RNAase activity was also detected in this fraction.

Animals↗

PubMed1989

[pH determination in human crevicular fluids. Examination of the pH meter and evaluation of the correlation between pH level and clinical findings or the microflora in each periodontal pocket].

The purpose of this study was to investigate the accuracy and reproduction of a microelectrode with a glass capillary, and to discuss the correlation between the pH level and the microflora in periodontal pockets or the clinical findings in the various stages of periodontal disease. The upper or lower anterior teeth of 34 patients with mild to severe periodontal disease were examined. Before the measurement, supragingival plaque was removed from each tooth. A special glass capillary was incorporated in the microelectrode to cover its tip, so that it would not touch the pocket walls or tooth surfaces during pH measurement. After the pH in the crevicular fluid was determined, subgingival plaque was collected with paper points from each periodontal pocket. This bacterial plaque was sonicated with saline solution, and examined under a phase contrast microscope with a calibrated eyepiece graticule to count and morphotype groupings of microorganisms as 1) coccoid forms, 2) rods, 3) filaments, 4) motile rods, 5) spirochetes or other cell types. Crevicular fluid flow measurements and clinical findings (pocket depth, and gingival inflammation) were also investigated. The following conclusions were drawn: The electrode with capillary was useful to determine the pH of the crevicular fluid clinically. A reduction in pH level was seen in deep pockets or severe gingival inflammation. A close correlation was seen between salivary and crevicular pH. The pH level was significantly positively related with the proportion of coccoid forms, but was negatively correlated with the proportion of motile organisms that are reported to be related with periodontal disease.

Dental Instruments↗

PubMed1989

Affinity of a DNA with highly repetitive sequence for nuclear proteins from rat liver.

A nuclear scaffold fraction (designated P fraction elsewhere) comparable to a nuclear matrix was prepared from rat liver. This fraction was composed mainly of 45-49 kDa proteins and high-molecular-weight proteins (more than 90 kDa). In addition, a 370-bp repetitive sequence DNA fragment was derived predominantly from the EcoRI digest of the deproteinized P fraction. By an immunoblot affinity assay with the P fraction, the fragment was shown to have affinity for each of the 107- and 115-kDa proteins. Moreover, by a filter binding assay with a mixture of these proteins, the affinity level was estimated to be about 6 times as high in the native (double-stranded) fragment as in the denatured (single-stranded) fragment.

Animals↗

PubMed1989

[A case report of aortic and mitral regurgitation combined with ankylosing spondylosis].

The purpose of this communication is to present a successful case of surgical treatment of aortic and mitral valve regurgitation associated with ankylosing spondylosis. A 48-year-old male was admitted with symptoms of palpitation and shortness of breath. His heart murmur had been pointed out for 4 months prior to this admission. His previous history did not show any evidence of rheumatic heart disease. Retrograde aortography showed moderate to severe aortic valvular regurgitation and echocardiography revealed mitral valve regurgitation with minor degree. At the same time he complained of rigidity of neck muscle as well as back pain for last 15 years. He underwent aortic valve replacement and mitral valve was left alone. His postoperative course was uneventful. In Japan, aortic valve regurgitation associated with ankylosing spondylosis has been reported to be very rare compared to the European or American people. Several important features in the diagnosis and operative treatment for this combination of diseases have been also discussed.

Aortic Valve Insufficiency↗

PubMed1989

[Anesthetic management of a patient with perforated necrotic trachea after radical esophageal cancer surgery].

We anesthetized a 69-year-old man with perforated necrotic trachea after radical esophageal cancer surgery. We recognized during the reoperation that necrotizing part of the trachea was perforated from the cricoid cartilage to 2cm above the carina. We ventilated the both lungs successfully without leaks by inserting a double-lumen tube into the trachea after tracheostomy. Postoperatively, the carina and the main bronchi were also necrotized and perforated. We ventilated the both lungs without leaks by inserting two single-lumen tubes into the left and right bronchi separately. But, eventually the distal part of the both bronchi was also necrotized and perforated. Finally, the patient died of respiratory failure due to hypoventilation on the 7th day after the re-operation. We should remember this type of emergency complication after radical esophageal cancer surgery.

Aged↗

PubMed1988

Purification and properties of a magnesium-dependent endodeoxyribonuclease endogenous to rat-liver nuclei.

An Mg2+-dependent endonuclease has been purified from a 0.6 M NaCl extract of rat-liver nuclei by a series of chromatographic procedures and finally by isoelectric focusing (IEF) electrophoresis. The nuclease fraction prepared by the IEF electrophoresis (IEF fraction) was shown to have a pI value of 7.1 and to migrate as a single band to a molecular-weight position of 36,500 on SDS-polyacrylamide gel. The IEF fraction was subjected to a sedimentation analysis. In a hypotonic buffer (10 mM Tris), the nuclease activity sedimented to have an S value of 4.1 S. However, in an isotonic buffer (0.15 M NaCl), this fraction exhibited two activity peaks of 2.8 and 4.3 S. In a hypertonic buffer (0.3 M NaCl), almost all of the nuclease activity sedimented at 2.7-2.8 S. In this connection, values of 2.8 and 4.3 S were determined to correspond to molecular weights of about 36,000 and 70,000, respectively. Thus, an Mg2+-dependent endonuclease, endogenous to rat-liver nuclei, has been inferred to exist in the reversible form of a monomer/homodimer as its native state. Moreover, the IEF fraction formed single-strand nicks more rapidly than double-strand cuts in pBR322 DNA, and preferentially produced deoxyguanosine 5'-monophosphate termini in the DNA at an early incubation time. In addition, RNAase activity was not detected in this fraction.

Animals↗

PubMed1987

Cat hindlimb motoneurons during locomotion. I. Destination, axonal conduction velocity, and recruitment threshold.

Fine flexible wire microelectrodes chronically implanted in the fifth lumbar ventral root (L5 VR) of 17 cats rendered stable records of the natural discharge patterns of 164 individual axons during locomotion on a treadmill. Fifty-one out of 164 axons were identified as motoneurons projecting to the anterior thigh muscle group. For these axons, the centrifugal propagation of action potentials was demonstrated by the technique of spike-triggered averaging using signals recorded from cuff electrodes implanted around the femoral nerve. The axonal conduction velocity was measured from the femoral nerve cuff records. For 43/51 motoneurons, the corresponding target muscle was identified by spike-triggered averaging of signals recorded from bipolar EMG electrodes implanted in each of the anterior thigh muscles: vastus intermedius, medialis and lateralis, sartorius anterior and medialis, and rectus femoris. For 32/51 motoneurons, the recruitment threshold during locomotion was determined from the mean value of the rectified digitally smoothed EMG of the target muscle measured at the time when the motoneuron fired its first spike for each step. The recruitment threshold of every motoneuron was relatively constant for a given speed of walking, but for some units there were small systematic variations as a function of treadmill speed (range: 0.1-1.3 m/s). Recruitment thresholds were standardized with respect to the mean value of peak EMG activity of the target muscle during 16 s of walking at 0.5 m/s. For 28/51 motoneurons recorded in nine cats, recruitment thresholds (range: 3-93% of peak target muscle EMG) were linearly correlated (r = 0.51, P less than 0.02) to axonal conduction velocities (range: 57-117 m/s). In addition, for seven recorded pairs of motoneurons that projected to the same muscle in the same cat, the recruitment thresholds were ordered by relative conduction velocities. Taken together, these results are consistent with the notion that, in normal cat locomotion up to a medium trot, anterior thigh motoneurons are progressively recruited in an orderly fashion.

Action Potentials↗

PubMed1987

Cat hindlimb motoneurons during locomotion. II. Normal activity patterns.

Activity patterns were recorded from 51 motoneurons in the fifth lumbar ventral root of cats walking on a motorized treadmill at a range of speeds between 0.1 and 1.3 m/s. The muscle of destination of recorded motoneurons was identified by spike-triggered averaging of EMG recordings from each of the anterior thigh muscles. Forty-three motoneurons projected to one of the quadriceps (vastus medialis, vastus lateralis, vastus intermedius, or rectus femoris) or sartorius (anterior or medial) muscles of the anterior thigh. Anterior thigh motoneurons always discharged a single burst of action potentials per step cycle, even in multifunctional muscles (e.g., sartorius anterior) that exhibited more than one burst of EMG activity per step cycle. The instantaneous firing rates of most motoneurons were lowest upon recruitment and increased progressively during a burst, as long as the EMG was still increasing. Firing rates peaked midway through each burst and tended to decline toward the end of the burst. The initial, mean, and peak firing rates of single motoneurons typically increased for faster walking speeds. At any given walking speed, early recruited motoneurons typically reached higher firing rates than late recruited motoneurons. In contrast to decerebrated cats, initial doublets at the beginning of bursts were seen only rarely. In the 4/51 motoneurons that showed initial doublets, both the instantaneous frequency of the doublet and the probability of starting a burst with a doublet decreased for faster walking speeds. The modulations in firing rate of every motoneuron were found to be closely correlated to the smoothed electromyogram of its target muscle. For 32 identified motoneurons, the unit's instantaneous frequencygram was scaled linearly by computer to the rectified smoothed EMG recorded from each of the anterior thigh muscles. The covariance between unitary frequencygram and muscle EMG was computed for each muscle. Typically, the EMG profile of the target muscle accounted for 0.88-0.96 of the variance in unitary firing rate. The EMG profiles of the other anterior thigh muscles, when tested in the same way, usually accounted only for a significantly smaller fraction of the variance. Brief amplitude fluctuations observed in the EMG envelopes were usually also reflected in the individual motoneuron frequencygrams. To further demonstrate the relationship between unitary frequencygrams and EMG, EMG envelopes recorded during walking were used as templates to generate depolarizing currents that were applied intracellularly to lumbar motoneurons in an acute spinal preparation.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗

PubMed1987

Cat hindlimb motoneurons during locomotion. III. Functional segregation in sartorius.

Cat sartorius has two distinct anatomical portions, anterior (SA-a) and medial (SA-m). SA-a acts to extend the knee and also to flex the hip. SA-m acts to flex both the knee and the hip. The objective of this study was to investigate how a "single motoneuron pool" is used to control at least three separate functions mediated by the two anatomical portions of one muscle. Discharge patterns of single motoneurons projecting to the sartorius muscle were recorded using floating microelectrodes implanted in the L5 ventral root of cats. The electromyographic activity generated by the anterior and medial portions of sartorius was recorded with chronically implanted electrodes. The muscle portion innervated by each motoneuron was determined by spike-triggered averaging of the EMGs during walking on a motorized treadmill. During normal locomotion, SA-a exhibited two bursts of EMG activity per step cycle, one during the stance phase and one during the late swing phase. In contrast, every recorded motoneuron projecting to SA-a discharged a single burst of action potentials per step cycle. Some SA-a motoneurons discharged only during the stance phase, whereas other motoneurons discharged only during the late swing phase. In all cases, the instantaneous frequencygram of the motoneuron was well fit by the rectified smoothed EMG envelope generated by SA-a during the appropriate phase of the step cycle. During normal locomotion, SA-m exhibited a single burst of EMG activity per step cycle, during the swing phase. The temporal characteristics of the EMG bursts recorded from SA-m differed from the swing-phase EMG bursts generated by SA-a.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1986

Adjustment errors of feedback guided human forearm movements elicited by random position signal sequences.

The effects of visual and auditory relevant feedback on human forearm movements elicited by random position signal sequences were examined. We observed the adjustment error sequences when the arm moved briskly and accurately to the target position. As the results, the mean adjustment errors for each speed (clock interval) of random position signal sequence are different in the left-right target positions, and also different in the flexion-extension movements. In faster speed (1 s), the adjustment errors are approximately flat as compared with those in other speeds, on the other hand, in moderate speed (2 s) or slower speed (3 s), these indicate a upward tendency from left to right positions, and also indicate a upward tendency from flexion to extension movements. However, in the reaction times, the moving times, and the adjusting times, there are no significant differences for the left-right target positions and for the flexion-extension movements.

Acoustic Stimulation↗

PubMed1986

Endonucleolytic activities of nuclei from rat ascites hepatoma.

By autodigestion (endogenous endonucleolysis) of rat liver (RL) or rat-ascites hepatoma (AH) nuclei, the nucleosomes were released from the RL, but not from the AH, nuclei. In contrast, by micrococcal nuclease digestion (exogenous endonucleolysis), the nucleosomes were released more rapidly from the AH than from the RL nuclei. A 0.6 M NaCl extract of the RL or AH nuclei was filtered through a Sephadex G-100 column. The resulting topoisomerase fraction was subjected to DNA relaxation and catenation assays with pBR322 DNA as a substrate. Consequently, the relaxation activity was almost the same between the RL and AH fractions, whereas the catenation activity was much higher in the AH fraction.

Animals↗

PubMed1985

Differences between visually triggered human forearm movements with visual and auditory relevant feedback.

The effects of visual and auditory relevant feedback on human forearm movements elicited by random position signal sequences were examined. Forearm movements were performed with four feedback conditions. We observed the reaction time, the holding time, and the adjustment error sequences when the arm moved briskly and accurately to the target position. As the results, the reaction times for auditory relevant feedback were shorter than those for the others (visual or no feedback). The holding times for auditory relevant feedback were longer than those for the others. And the subjects had about one adjustment error to terminate on the target zone.

Acoustic Stimulation↗

PubMed1985

Anticarcinogenic action of an alcohol-insoluble fraction (LAP1) from culture medium of Lentinus edodes mycelia.

From the culture medium of Lentinus edodes mycelia, water-soluble material (LEM) was prepared and further fractionated by alcohol precipitation and gel filtration on Sepharose 6B. The resulting fraction of xylose-rich proteoglycan at the void volume was designated as LAP1. The 25% and 50% survival rates of hepatoma-bearing rats were raised by intraperitoneal (i.p.) administration of LAP1 at doses of 3-10 mg/kg (an optimum dose, 3 mg/kg). This fraction did not suppress in vitro cell proliferation of the hepatoma. Moreover, the i.p. administration of LAP1 significantly augmented the activity of macrophage-migration inhibition of the splenic cells from hepatoma-bearing rats in the early stage after transplantation. Thus, the anticarcinogenic action of LAP1 would partly be interpreted by host-dependent immunomodulation.

Animals↗