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Biomedical subjects

M Hirakawa

Publications and source records attributed to M Hirakawa.

At least 19 recordsLinked to original sources
PubMed1992

Changes of chemoarchitectural organization of the rat spinal cord following ventral and dorsal root transection.

Time-related changes in the distribution of chemical messengers in the rat spinal cord following the transection of dorsal and ventral roots were observed by using immunohistochemistry for the following antigens: microtubule-associated protein 2 (MAP2), calcitonin gene-related peptide (CGRP), substance P (SP), galanin (Gal), Met-enkephalin (Enk), neuropeptide Y (NPY), and serotonin (5-HT). To investigate dendrocytoarchitectonic organizational changes, morphometric analyses were performed on both the gray and the white matter of tissue samples stained with MAP2 antiserum. A significant reduction in the area of gray matter on the lesioned side was seen from 1 to 24 weeks postoperation, and progressive changes in the shape of the gray matter were also observed. CGRP-immunoreactive fibers were reduced in number in the posterior horn after root transection, except in the lateral part of lamina I. In contrast, CGRP immunoreactivity in the anterior horn cells of the ipsilateral side was increased early after transection, but later it progressively decreased. Root transection also caused significant reduction in the number of SP-immunoreactive fibers in the posterior horn, but no changes were seen in the anterior horn. Gal immunoreactivity was also affected by root transection, and it changed in a similar way to CGRP immunoreactivity. 5-HT-immunoreactive fibers were increased in the posterior horn after transection, and later decreased. In the anterior horn, there were no changes in the intensity or distribution pattern of 5-HT-immunoreactive nerve fibers following root transection. Enk and NPY immunoreactivity in the anterior and posterior horns was not affected by root transection up to 24 weeks postoperative. These results show that spinal root transection caused significant changes in the chemoarchitectural organization of nerve fibers containing certain types of chemical messengers, such as CGRP, SP, Gal, and 5-HT, in addition to altering dendritic geometry in the spinal cord.

Animals↗
PubMed1992

Time-related changes in the labeling pattern of motor and sensory neurons innervating the gastrocnemius muscle, as revealed by the retrograde transport of the cholera toxin B subunit.

Morphological changes in the motor and sensory neurons in the lumbar spinal cord and the dorsal root ganglia were investigated at different survival times following the injection of the B subunit of cholera toxin (CTB) into the medial gastrocnemius muscle. Unconjugated CTB, visualized immunohistochemically, was found to be retrogradely transported through ventral and dorsal roots to motor neurons in the anterior horn, each lamina in the posterior horn, and ganglion cells in the dorsal root ganglia at L3-L6. The largest numbers of labeled motor neurons and ganglion cells were observed 72 h after the injection of CTB. Thereafter, labeled ganglion cells were significantly decreased in number, whereas the amount of labeled motor neurons showed a slight reduction. Motor neurons had extensive dendritic trees filled with CTB, reaching lamina VII and even the pia mater of the lateral funiculus. Labeling was also seen in the posterior horn, but the central and medial parts of laminae II and III had the most extensively labeled varicose fibers, the origin of which was the dorsal root ganglion cells. The results indicate that CTB is taken up by nerve terminals and can serve as a sensitive retrogradely transported marker for identifying neurons that innervate a specific muscle.

Animals↗
PubMed1992

Effectiveness of pressure support ventilation for mechanical ventilatory support in patients with status asthmaticus.

We compared the effects of pressure support ventilation (PSV) with those of assist control ventilation (ACV) on breathing patterns and blood gas exchange in six patients with status asthmaticus. Both PSV and ACV delivered adequate minute ventilation (PSV: 7.5 +/- 1.4 l/min/m2, ACV: 7.3 +/- 1.3 l/min/m2) to correct respiratory acidosis (pH = 7.33 +/- 0.12 during both PSV and ACV) and prevent hypoxia. Peak airway pressure during PSV was significantly lower with the same tidal volume than that during ACV (PSV: 30 +/- 10 cmH2O (2.9 +/- 1.0 kPa), ACV: 50 +/- 13 cmH2O (4.9 +/- 1.3 kPa)). The lower airway pressure during PSV was due to persistent inspiratory muscle activity. The oxygen cost of breathing estimated by oxygen consumption was equivalent in both modes. We conclude that PSV is effective in supplying tidal volumes adequate to improve hypercarbia at markedly lower airway pressures than ACV.

Adolescent↗
PubMed1992

Adrenaline absorption: effect of pH in mepivacaine and bupivacaine solutions. A clinical study during halothane anesthesia.

The effect of the pH of the solution on the rate of absorption into the blood stream of locally-injected adrenaline using an adrenaline solution mixed with either mepivacaine or bupivacaine was investigated. Forty patients undergoing elective craniotomy received one of the following five solutions for subcutaneous and subgaleaic injection in the dose 0.5 ml/kg: 1) mepivacaine-adrenaline (pH = 6.1), 2) mepivacaine-adrenaline (pH = 7.5), 3) bupivacaine-adrenaline (pH = 6.1), 4) bupivacaine-adrenaline (pH = 7.4), or 5) adrenaline (pH = 6.1). Both mepivacaine and bupivacaine added to the adrenaline solution increased the plasma concentration of adrenaline. Alkalinization attenuated the peak concentration of adrenaline in the case of a mepivacaine-adrenaline solution, but not in the case of a bupivacaine-adrenaline solution.

Absorption↗
PubMed1992

Role of afferent neural input in regression of sensory paralysis during epidural analgesia.

This study was designed to determine the role of the afferent peripheral neural input in the regression of sensory analgesia during epidural analgesia. Eighteen patients who underwent minor obstetric or gynecologic surgery under lumbar epidural analgesia with lidocaine were divided into three groups. Group A received electrical single twitch stimulation at the spinal nerve dermatome one segment rostrad of the proximal extent of sensory paralysis. Group B received electrical twitch stimulation at the anterior crural region where nerve block may have been most profound in this study. Group C was assigned as a control and did not receive any stimulation. The patients received the stimulation for 60 min (i.e., from 80 to 140 min after the epidural injection). The range of sensory analgesia at 140 min was compared with that at 80 min. The regression of sensory analgesia in group B or C was 1 +/- 0 (mean +/- SD) spinal nerve segments, but in group A it was 5 +/- 1, which was significantly (P less than 0.0025) larger than the others. We conclude that the afferent peripheral neural input to a spinal segment where the nerve block is incomplete may accelerate the regression of sensory analgesia from epidural analgesia.

Adult↗
PubMed1992

Influence of spinal cord hemisection on the configurational changes in motor and primary afferent neurons and the chemical messenger alterations in the rat lumbar segments.

Cholera toxin B subunit (CTB), a retrograde transport marker, was injected into the rat gastrocnemius muscles, and changes in CTB-labeling pattern of motoneurons and primary afferent neurons at the level L4 and L5 after spinal cord hemisection of the L1 level were observed in conjunction with the alterations of chemical messengers such as serotonin (5-HT), calcitonin gene-related peptide (CGRP), substance P (SP), galanin (Gal), Met-enkephalin (Enk), and neuropeptide Y (NPY). Motoneurons at the L4 and L5 levels on the lesioned side exhibited significant shrinkage of their dendritic arbors without apparent loss of their number throughout all stages from 1 to 12 weeks after the hemisection of the spinal cord. Postoperatively, central processes of neuron of the dorsal root ganglia (DRG) on the lesioned side increased progressively compared to that on the contralateral side with the passage of time. The percentage of CTB-labeled neurons in the DRG has been consistently smaller in number on the lesioned side after the operation, and the difference between sides became more apparent during the later postoperative stages. 5-HT-containing fibers in the anterior and posterior horns on the lesioned side showed a significant decrease in the number, while no apparent changes were observed in the distribution of nerve fibers containing CGRP, SP, Gal, Enk, and NPY.

Afferent Pathways↗
PubMed1992

[Morphometric analysis in the rat spinal cord following peripheral nerve transection with the use of MAP2 immunohistochemistry].

The physiological function of the spinal cord is regulated by two different kinds of information, namely, afferent inputs from the primary sensory fibers and descending inputs from the brain. The former conveys the sensory information from the peripheral region via the dorsal root ganglia to spinal interneurons or directly to motor neurons and brings about the voluntary and/or involuntary muscle movement. In the present study, the time-related changes in the dendrocytoarchitecture of the rat spinal cord following the transection of afferent and efferent connections from/to the peripheral organs were observed by using immunohistochemistry for microtubule-associated protein 2 (MAP2) and Nissl staining. To investigate the changes quantitatively, morphometric analyses were performed on the section of gray matter of tissue samples stained with MAP2-antisera. One to 24 weeks after hemitransection of the dorsal and ventral roots, a remarkable reduction in the area and progressive changes in the shape of the gray matter were seen in both the anterior and posterior horns on the lesioned side. These changes were found to be due to the reduction of the width of the anterior and posterior horns on the lesioned side rather than of the height. At the later postoperative stage, atrophy of the Fasciculus gracilis and disappearance of motoneurons on the lesioned side were recognized in Nissl stained tissue samples.

Animals↗
PubMed1992

[Perioperative blood glucose levels in children].

The perioperative blood glucose (BG) level may represent autonomic responses to various stresses by anesthesia and surgery. We studied the effects of regional blocks combined with general anesthesia on the BG response in pediatric patients. We could not find any significant differences in BG levels between blocked and non-blocked patients. However, BG levels of the children who had been hysterical or crying during the induction of anesthesia were significantly higher than those of the children who had been calm or sleeping. Forty healthy children, aged 1-3 yrs who were scheduled for elective urological surgery were studied. Anesthesia was induced with halothane in oxygen. The anesthesiologist recorded the children's attitude before and during the induction of anesthesia, and described as "calm or asleep (Calm-group), and hysterical or crying (Crying-group)". Patients were assigned randomly to two groups as follow; Group A (n = 20): receiving nerve blocks, Group B (n = 20): without the blocks. The anesthesia was maintained with 1-2.5% halothane in oxygen required to maintain the hemodynamic parameters within 10% of baseline value before surgery. Both groups received lactated-Ringer's solution during the study period. The venous BG levels were determined 5 times, i.e. immediately after asleep, 5, 15, 30 minutes after skin incision and at the conclusion of surgery. BG levels were compared between groups using Mann-Whitney Test. There was no significant difference in BG levels between Group A and B throughout the study period. But BG values of Crying-group (n = 9) were significantly higher than those of Calm-group (n = 31) during perioperative period.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Inhalation↗
PubMed1992

[In situ hybridization histochemistry for the kidney diseases].

Crucial points of in situ hybridization methods were pointed out for study on the kidney diseases at molecular level. As examples of in situ hybridization study on kidney, we introduced two cases: 1) expression of the hepatocyte growth factor gene during renal regeneration after unilateral nephrectomy, and 2) induction of the metallothionein gene expression by ischemic acute renal failure. We proposed an idea to establish a probe bank for the in situ hybridization study.

Acute Kidney Injury↗
PubMed1992

[Anesthesia for a patient with Bloom's syndrome].

Bloom's syndrome (BS) is a rare autosomal recessive disorder. The disease is due to chromosome breakage and recombination. The principal features of the syndrome are short stature of prenatal onset, a photosensitive telangiectasic erythema of the face and a marked predisposition to the development of malignant diseases. We are unaware of any previous report of the anesthetic management of a BS patient. In this paper, we reported the anesthetic experience of a male patient (37-yr-old, 26 kg, 136 cm) with Bloom's syndrome who underwent emergency laparotomy. The awake laryngoscopy was carried out, but we could not see the vocal cord directly. The trachea was blindly intubated and anesthesia was induced and maintained with fentanyl, vecuronium and enflurane in 100% oxygen. In a BS patient we should pay attention to potential difficulties with mask fit and laryngoscopy.

Adult↗
PubMed1992

[Effects of lidocaine on stimulation-coupled responses of neutrophils and protein kinase C activity].

The effects of lidocaine on superoxide generation and other stimulation-coupled responses of neutrophils induced by 12-phorbol myristate 13-acetate (PMA) were studied. Depolarization of membrane potential, superoxide generation and chemiluminescence response were inhibited by lidocaine in a concentration dependent manner. Lidocaine inhibited protein kinase C (PKC) activity in a manner competitive with phosphatidylserine. Lidocaine also inhibited the phosphorylation of 47 kDa neutrophil cytoplasmic protein, a phosphorylated protein required for activation of NADPH oxidase. The inhibitory action of lidocaine on PKC activity may correlate with the inhibition of superoxide generation induced by PMA.

Animals↗
PubMed1992

[Troubled endotracheal intubation: an adult case of anomalous tracheal bronchus].

We experienced troubled endotracheal intubation in an adult patient with asymptomatic tracheal bronchus. The breath sounds of the right upper lobe were found to be absent right after the placement of a tracheal tube. An anomalous tracheal bronchus (displaced right upper lobar bronchus originating about 1 cm above carina) was found by fiberoptic bronchoscopy. The length of trachea of the patient was about 6 cm shorter than that of the normal value of adult male, which significantly reduced the safe range of positioning a tracheal tube. In a patient with this anomaly, who is otherwise healthy, a placement of a tracheal tube may cause pulmonary complications. Thus, as a diminished breath sound is found to be located at the upper right lobe after endotracheal intubation, we have to think of tracheal bronchus as one of the possible causes.

Aged↗
PubMed1991

Breath hydrogen test using water-diluted lactulose in patients with gastrointestinal amyloidosis.

To investigate small bowel motility in gastrointestinal amyloidosis, lactulose breath hydrogen tests were performed on 16 patients with histologically proven amyloidosis and 12 age- and sex-matched controls. Fasting breath hydrogen concentration (FBHC) was not significantly different between the two groups, but there was a tendency for FBHC in symptomatic amyloidosis patients (median 31.5, range 3-78 ppm) to be higher than in asymptomatic amyloidosis patients (4, 0-34 ppm, 0.05 less than P less than 0.1) and controls (6, 1-19 ppm, 0.05 less than P less than 0.1). Orocecal transit time (OCTT) was significantly delayed in the amyloidosis group (median 150, range 40-220 min) when compared to the controls (60, 20-110 min, P less than 0.01), but OCTT was not statistically different between symptomatic and asymptomatic amyloidosis patients. These data suggest an impaired motility of the stomach and small intestine in gastrointestinal amyloidosis and the possible role of small intestinal dysfunction such as bacterial overgrowth and malabsorption in the occurrence of symptoms in this disorder.

Adult↗
PubMed1991

Hemodynamic effect of the prone position during anesthesia.

We studied 21 patients undergoing lumbar spinal surgery under halothane anesthesia on a convex saddle frame, in order to determine the hemodynamic effect of the prone position. A thermodilution pulmonary arterial catheter was placed in 14 patients (Group PA-1: n = 8; and Group PA-2: n = 6), and an inferior vena caval catheter in the remaining seven patients (Group IVC). Group PA-1 and Group IVC patients were placed in the prone position on a convex saddle frame. In the prone position, the cardiac index (CI) decreased significantly from 3.1 +/- 0.5 to 2.5 +/- 0.3 (l.min-1.m-2, mean +/- s.d., P less than 0.01) without accompanying significant changes in the other hemodynamic variables in Group PA-1. The postural change in Group IVC did not exert a significant effect on the inferior vena caval pressure. Group PA-2 were initially placed in the flat prone position on a flat saddle frame, which produced no significant changes in the hemodynamic variables. Then the convex curvature of the frame was adjusted to the grade appropriate for surgery, which produced a significant reduction in CI (from 2.9 +/- 0.3 to 2.4 +/- 0.4, P less than 0.05). We conclude that the prone position itself may not interfere with the circulatory function. The prone position using a convex saddle frame causes significant reductions in CI, but little change in the other hemodynamic variables.

Anesthesia, Inhalation↗
PubMed1991

[Clinical significance of thrombocytopenia associated with hemorrhagic cerebrovascular diseases].

We investigated the clinical significance of thrombocytopenia (platelet counts less than 10 x 10(4)/mm3) associated with hemorrhagic cerebrovascular disease. This study was conducted in 96 patients suffering from hemorrhagic cerebrovascular diseases. We divided the clinical course into 3 stages: acute (from the 1st to 7th day), subacute (8th-21st day) and chronic (after the 22nd day). The average age of the patients with thrombocytopenia (TCP) was 60.6 years old. TCP was more frequent in men (81.3%) than in women (18.7%). TCP developed in 18.6% (8/43) of patients with subarachnoid hemorrhage (SAH) and in 15.1% (8/53) of those with intracerebral hemorrhage (ICH). Among the patients with SAH, four were in the acute stage, three in the subacute stage and two in the chronic stage. TCP due to SAH was more likely to develop in the acute and/or subacute stage. TCP due to SAH showed two peak appearances: the first was within 24 hours (n = 3), and the second was around 10 days after onset (n = 3). The cause of TCP in its late peak appearance was presumed to be the consumption of platelets due to microembolism induced by vasospasm and/or hemodilution therapy. Among patients with ICH, five cases were in the acute stage, three in the subacute stage and two in the chronic stage. TCP due to ICH was more likely to develop in the acute stage. Fifty percent (4/8) of the patients with ICH had TCP on admission. This data suggested that TCP was possibly a cause or an inducer for ICH.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Effect of nitroglycerin and nicardipine on ICG excretion during halothane anesthesia].

We evaluated the effect of nitroglycerin and nicardipine on ICG excretion during halothane anesthesia in man. Induced hypotension with nitroglycerin during halothane anesthesia produced a significant prolongation in ICG excretion. No such significant prolongation occurred in the patients who received nicardipine. The results suggest that a reduction in hepatic blood flow during anesthesia may be much less in patients who receive halothane with nicardipine than in those who receive halothane with nitroglycerin.

Adult↗
PubMed1991

[On the etiology of the loose shoulder--biochemical studies on collagen from joint capsules].

In order to investigate the etiology of loose shoulder, biochemical characteristics of collagens from four major joint capsules of extremities and from joint capsules of loose shoulder have been investigated. Joint capsules of normal shoulder were found to synthesize less collagen fibers comparing to those of other major joints. Furthermore formation of inter-molecular cross-links of collagen from shoulder joint capsule was relatively lower than that of collagens from other major joints. Noteworthy was the fact that collagen fibers from joint capsules of loose shoulder were more soluble and contain less amount of the reducible cross-links than those from joint capsules of the normal shoulder. These data suggest that collagen synthesis and formation of collagen fibers vary with the differences in joint structures, functions and movements. It may also be implied that the joint capsules of loose shoulder produce immature collagen fibers which may reflect the clinical feature of the disease.

Adolescent↗