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Biomedical subjects

R Nakamura

Publications and source records attributed to R Nakamura.

At least 325 records · Page 18Linked to original sources
PubMed1988

Revascularization of digits after prolonged warm ischemia.

Four cases of digit revascularization after prolonged warm ischemia are presented. Amputation injuries occurred in the summer, with the average temperature above 23 degrees C. The average warm ischemia time was 24 hr (range: 20 to 30 hr) from injury to the time of establishment of arterial inflow. Complete survival was achieved in three cases and partial survival in one case. Previously, eight to ten hours were believed an acceptable limit for warm ischemia; however, this study indicates that successful revascularization is still possible, even after a much longer period of time.

Adult↗
PubMed1988

Dual vascularized fibula transfer on a single vascular pedicle: a useful technique in long bone reconstruction.

The use of dual vascularized fibula transfer on a single vascular pedicle for reconstruction of long bone defect is described. This technique involves dividing one length of donor vascularized fibula into two segments, without cutting the vessels. The vessels are then folded, thereby supplying blood circulation to both bones. Since 1985 the authors have treated six cases of bone reconstruction using this method. Two of these six cases are reported, with follow-up periods of over one year.

Adult↗
PubMed1988

The relationship between walking speed and muscle strength for knee extension in hemiparetic stroke patients: a follow-up study.

Walking speed and isokinetic strength of knee extension were examined in 18 hemiparetic stroke patients prior to, and 4 and 8 weeks after gait training. Although increase of the walking speed did not coincide with that of the isokinetic strength of the affected and non-affected sides, regression analyses revealed that the strength of the affected side was the primary determinant of the walking speed and the variance explained by it gradually increased with a period of the training.

Aged↗
PubMed1988

Walking cycle after stroke.

Temporal-distance parameters of gait, maximum walking speed, walking rate and stride length, were successively examined in 10 hemiparetic stroke patients for 8 weeks after starting gait training. In patients with walking speed less than 20 m/min i.e., walking rate less than 90 steps/min, the increase of walking speed was significantly related to that of walking rate and stride length. In patients with walking speed greater than 20 m/min, the increase of walking speed correlated only to that of stride length, indicating that a limiting factor of walking speed in hemiparetic patients was the decreased stride length.

Adult↗
PubMed1988

Effect of warning signal on reaction time and EMG activity of the biceps brachii muscle in elbow flexion and forearm supination.

Using a reaction time (RT) task, the biceps brachii muscle was investigated in five healthy subjects to determine whether EMG in the initial phase of activity is dependent upon the direction of movement, i.e., elbow flexion and forearm supination, and/or influenced by the presence or absence of warning signal. Results showed that in the presence of warning EMG-RT of forearm supination was faster than that of elbow flexion, and that the reverse occurred in the absence of warning. The warning signal significantly reduced EMG-RT of both movements and the reduction of EMG-RT was larger in supination than flexion. Compared to forearm supination, large amplitude potentials were observed during elbow flexion. The warning suppressed EMG activities of both movements within 30 msec after their initiation. The present study indicates that the biceps brachii muscle exhibits a motor response program specific to the direction of movements and that preparatory set conditioned by warning shortens RT and also suppresses EMG activities.

Action Potentials↗
PubMed1988

Inhibitory effect of CR-1409, a competitive inhibitor of cholecystokinin, on pancreatic exocrine secretion in the conscious rat.

The inhibitory effect of CR-1409, a new glutaramic acid derivative and a competitive inhibitor for cholecystokinin (CCK), on the basal and CCK-stimulated pancreatic secretion was examined in the conscious rat in vivo. Rats were prepared with cannulae draining pure bile and pancreatic juice separately and with a duodenal cannula and right and left jugular vein cannulae. Plasma CCK level increased to 3.65 +/- 0.79 and 19.9 +/- 4.47 pM (mean +/- S.E.) by a 2-hr infusion of 100 and 300 pmole/kg/hr of CCK-octapeptide (CCK-8), respectively. Simultaneous infusion of 170 nmole/kg/hr of CR-1409 completely abolished pancreatic responses to 100 pmole/kg/hr of CCK-8. Infusion of CR-1409 at rate of 57 nmole/kg/hr slightly but significantly inhibited CCK-8 (100 pmole/kg/hr)-stimulated secretion. Pancreatic responses to 300 pmole/kg/hr of CCK-8 were partially inhibited but not completely abolished by the 170 nmole/kg/hr of CR-1409. Neither the basal pancreatic secretion nor the bile secretion was affected by CR-1409. We conclude that CR-1409 inhibited CCK-stimulated pancreatic secretion in vivo.

Animals↗
PubMed1988

Time course of tension development of knee extensor muscle on twitch, tetanic, and fast voluntary contraction in normal subjects.

Tension lag time (TLT), a latency from the onset of electromyographic activities of prime mover muscle to the rise of tension, of knee extensor muscle was measured at twitch, tetanic, and fast voluntary contraction in three normal subjects. Twitch and tetanic contractions were evoked by four different strengths of electrical stimuli, and the peak tensions attained at fast voluntary contraction were within the range of tensions evoked by electrical stimulation. In each mode of contraction, the relationship between TLT and peak tension (Fmax) was approximated by a hyperbolic function of Fmax (TLT-a) = b. TLT was influenced by three factors: (1) Fmax, the greater Fmax, the shorter TLT; (2) force detection level to point out timing of the rise of tension, the higher the level, the longer TLT was; and (3) the mode of contraction, shortest at the twitch, longest at the voluntary, and intermediate in the tetanic contraction.

Adult↗
PubMed1988

Application of computer-assisted gait training (CAGT) program for hemiparetic stroke patients: a preliminary report.

Thirteen hemiparetic stroke patients (experimental group) underwent the recently developed CAGT program during the early recovery phase, and their functional gain in walking capacity was compared with 17 other stroke patients (control group) being prescribed the conventional gait training program. Results showed that the recovery process of maximum walking speed after a stroke fitted the hyperbolic function in the experimental group and furthermore, the maximum walking speed that might be attained could be higher in the experimental than the control group. The CAGT program makes it possible to analyze and predict gait capacity, i.e., maximum walking speed, and to increase the functional gain of patients during early intensive physical therapy.

Adult↗
PubMed1988

Prolonged tension lag time of knee extensor muscle on twitch contraction in patients with spastic hemiparesis.

Tension lag time on electric stimulation (TLTe), i.e., latency from the stimulus to the rise of tension, and contraction time (CT) of the rectus femoris muscle on twitch contraction were measured on the affected and non-affected sides of eight patients with spastic hemiparesis due to stroke. Both TLTe and CT were significantly longer on the affected side than on the non-affected side, suggesting changes in contractile properties of the spastic muscle.

Aged↗
PubMed1988

Effect of ankle-foot orthosis (AFO) on body sway and walking capacity of hemiparetic stroke patients.

Body sway, the total length of the sway of the center of foot pressure (CFP) and maximum walking speed were examined with and without AFO in eight post-stroke hemiparetic patients. Without AFO, the CFP moved towards the non-affected limb and the body sway was large. Wearing AFO, the CFP shifted to the midposition and the body sway became small. Without AFO, the time to walk the prescribed distance was longer, the cadence slower and the steps shorter than with AFO. However, there was no correlation between the improvements in body sway and walking capacity. The AFO compensated only for the instability of the ankle joint but not for the dysfunction of the central nervous system after the stroke.

Aged↗
PubMed1988

Sequence of preparatory set for response movement.

Electromyographic reaction times (EMG-RTs) of the right biceps brachii muscle were examined for two movement patterns, elbow flexion and forearm supination, in 8 healthy male subjects under simple and complex RT conditions with varied preparatory intervals (PIs): 0, 200, 400, 600, and 800 msec. In the simple RT condition, the subject was informed of the movement patterns to be performed prior to beginning the trials. In the complex RT condition the subject had to choose one of the two movement patterns at the time of the presentation of a warning signal. The results indicated that: (1) compared with the simple RT condition a delay of about 100 msec. in over-all mean EMG-RT was observed at PI = 0 msec. in the complex RT condition; (2) the difference of over-all mean EMG-RT between the two RT conditions disappeared when PI = 400 msec.; and (3) the difference in EMG-RTs between flexion and supination in the complex RT condition became the same as that in the simple RT condition when PI = 700 msec. It is assumed that the preparatory set for response movements is organized in an order, resulting in the differentiation of RT.

Arousal↗
PubMed1988

Effect of reaction time condition on EMG activities of the biceps brachii muscle in elbow flexion and forearm supination.

Under simple- and choice-RT conditions, the biceps brachii muscle was examined in 8 healthy male subjects to determine how the temporal and spatial characteristics of elbow flexion and forearm supination differed at the initial phase of EMG activity and whether preparation or the presence of response uncertainty influenced the EMG outputs of the two movements. In the simple-RT condition, RT of supination was significantly faster than that of flexion but EMG activity of supination was less than that of flexion. In contrast, in the choice-RT condition, RT of flexion was significantly faster than that of supination but EMG activity of flexion was significantly reduced compared to supination. These findings indicate that advanced preparation or motor set facilitates the differentiation of RTs and EMG activities of the response movements and that response uncertainty causes a significant change in the temporal and spatial specificity of both elbow flexion and forearm supination.

Adult↗
PubMed1988

Choice reaction time of elbow flexion and extension during passive elbow motions.

The effect of passive elbow motions on electromyographic reaction times (EMG-RTs) of the biceps brachii for elbow flexion and the triceps for elbow extension was investigated in 8 normal subjects, using a choice-RT task, in which the subject was uncertain about the response direction to perform until the arrival of response signal after the passive motion started. Compared to the static condition, choice EMG-RTs shortened only when the direction of passive and response movements was the same. It seems that passive motions act as prior information on direction of movement in the choice-RT task.

Adult↗
PubMed1988

Meningiomas and hemorrhagic diathesis.

The physical act of operating on 13 patients with meningiomas was studied for its effect on the fibrinolytic system. Fibrinolytic abnormalities, mainly due to an increase of plasma fibrinolytic activity, appeared in three patients prior to, during, or after surgery. These patients demonstrated hemorrhagic diathesis in the operative wounds which was associated with a consumptive coagulopathy, namely, an increase of fibrin/fibrinogen degradation product concentration and a decrease of fibrinogen concentration in plasma. Antiplasmin agents (gabexate and tranexamic acid) were effective in minimizing loss of blood during and after the operation. Abnormal hyperfibrinolysis seems to play a role in hemostatic difficulties in patients undergoing surgery for meningioma.

Adult↗
PubMed1988

[Allotransplantation of islet endocrine aggregates].

Dissociated pancreatic islets form aggregates from single cell suspension by rotation culture. Islet cell aggregates, or neoislets, newly formed from Lewis islet cells were transplanted into diabetic ACI rats intraportally and prolongation of neoislet grafts was observed (mean survival time greater than 45.8 +/- 6.4 days). Five out of seven recipients were still normoglycemic at 60 days after transplantation. Transplantation of neoislets combined with 3 day cyclosporine therapy for recipients resulted in 100% survival at 60 days after transplantation. These findings indicate that neoislets can provide endocrine constitution for streptozotocin diabetic rats and enjoy prolonged survival. As predicted by cell-cell recognition in rotation mediated aggregation, neoislets can exclude mesenchymal cells which bear Ia antigen. Therefore reduced immunogenicity is accomplished.

Animals↗
PubMed1988

[Neural regulation of auto-grafted islets of Langerhans].

The possibility of vagal reinnervation to intrasplenic islets grafts was examined by measuring portal insulin response to electric stimulation of the dorsal vagus nerve in autografted dogs. Grafted islets responded appropriately to methacholine given intravenously. However, no insulin secretory response could be observed in grafted dogs after vagal stimulation, which markedly increased portal insulin levels in control dogs. Therefore, intrasplenic grafted islets are not under direct vagal control. At the basal state, normal oscillatory release of insulin was observed in grafted animals, suggesting that the mechanism of rhythmic basal insulin release is intrinsic to the islet of Langerhans with no regulatory input from the vagus or any element of normal pancreatic structure.

Animals↗
PubMed1988

[Early esophageal cancer discovered 6 months after endoscopic injection sclerotherapy of esophageal varices].

Early esophageal cancer was discovered in a 55-year-old male with liver cirrhosis six months after the start of treatment for esophageal varices by a series of endoscopic sclerotherapeutic injections using 5% ethanolamine oleate. A histological examination of the entire length of the resected esophageal wall revealed a carcinomatous lesion oralwards and far removed from the lesion where subsequent changes due to sclerotherapy were prominent. Further, the causal relationship between sclerotherapy and carcinoma is discussed.

Carcinoma, Squamous Cell↗