Biomedical subjects

T Ohwada

Publications and source records attributed to T Ohwada.

At least 91 records · Page 5Linked to original sources

PubMed1993

Correlation between intravascular pressure and risk of hemorrhage due to arteriovenous malformations.

The correlation between intraoperative pressure levels measured in the feeding arteries and in the draining veins, and the risk of hemorrhage from arteriovenous malformations (AVMs) is discussed. Feeding artery pressure (FAP) was significantly higher in AVMs with hemorrhage (57 +/- 11 mmHg) than in AVMs without hemorrhage (38 +/- 4), and draining vein pressure (DVP) in the former (24 +/- 5) was significantly higher than that in the latter (13 +/- 5). FAP and DVP were inversely related to the number of draining veins and size of the AVMs. The present study suggests that a high FAP and a high DVP may contribute to the development of hemorrhage from AVMs, and supports previous reports that small AVMs and AVMs with only one draining vein are susceptible to hemorrhage.

Blood Pressure↗

PubMed1993

Radical removal of craniopharyngioma: a long-term follow-up.

Radical removal of craniopharyngiomas was attempted as the primary treatment in 12 adult and six child patients. No postoperative radiotherapy was given to patients undergoing total removal, while those undergoing subtotal removal received 50-60 Gy. Overall evaluation showed 15 cases of total removal and three of subtotal removal. One patient died of septicemia 2 months postoperatively and another developed a recurrent tumor which was removed totally at a second operation. The mean follow-up period was 7 years. The quality of life was "excellent" in 10 patients, "good" in five, and "fair" in two. Visual losses were minimized and endocrinological disturbances treated medically. These satisfactory results indicate that radical surgical removal is the first choice for treatment of craniopharyngioma irrespective of the age of patients.

Adolescent↗

PubMed1993

Transmigration routes and a delayed systemic hypotension in rats after intraperitoneal injection of endotoxin from Escherichia coli.

An intraperitoneal injection of endotoxin (ETX; 3 mg/kg) to rats caused gradual decrease in the systemic arterial blood pressure for up to 3 hr, together with decrease in heart rate, increase in hematocrit, and changes in the core temperature (an initial increase and a subsequent decrease). Pretreatment of rats with indomethacin (10 mg/kg, p.o.) prevented the decrease in the systemic blood pressure and the changes in other three parameters. The intraperitoneal injection of ETX also induced a gradual increase in exudation of plasma for up to 3 hr, with increased levels of prostaglandin (PG) E2 and 6-keto-PGF1 alpha in the peritoneal exudate. Indomethacin inhibited the exudation of plasma. The levels of ETX in the arterial and portal venous plasmas began to increase 5 min after the intraperitoneal injection of ETX, and reached levels on the order of micrograms per milliliter plasma 10-20 min after the injection. The levels of ETX in the right and left thoracic lymph nodes, but not in the mesenteric lymph nodes, increased in parallel with those in the systemic arterial plasma. In conclusion, the delayed hypotension may be attributable to the mesenteric vasodilatation induced by PGs generated in the peritoneal cavity, and the ETX injected entered the systemic circulation mainly through lymphatic vessels, but in the initial stage, a part of ETX may be transmigrated into portal vein through damaged intestine.

Animals↗

PubMed1993

[Clinical study in patients with perimesencephalic subarachnoid hemorrhage of unknown etiology].

We have recognized a characteristic distribution of cisternal blood in 10 (43%) of 23 patients with subarachnoid hemorrhage (SAH) of unknown etiology. On the initial CT examination undertaken within 48 hours of the onset, blood from 10 patients was found to be more densely distributed in the cisterns around the brainstem. In this study, clinical characteristics and CT findings in those 10 cases were carefully evaluated and the CT findings were compared to those of 416 patients with aneurysmal SAH (anterior circulation aneurysm 368 cases, posterior circulation aneurysm 48 cases). There were seven men and three women, with an age ranging from 39 to 64 years (average age, 50.6 years). The follow-up period ranged from 4 to 45 months (average follow-up period, 23 months). Neurological grade (WFNS) on admission was I in 9 cases and III in one case. None of the patients suffered symptomatic vasospasm, hydrocephalus or rebleeding. All the patients had favourable outcome and were categorized as good recovery according to the Glasgow Outcome Scale. In comparison with the cases of aneurysmal SAH, especially in comparison with 48 cases with SAH caused by posterior circulation aneurysm, 43 cases could be easily distinguished on CT. The other 5 cases showed almost the same pattern of SAH on CT, but 4 cases could be differentiated by either the extension of SAH to the interhemispheric fissure or the presence of intraventricular hemorrhage. Only one case could not be differentiated on CT. Thus SAH located only around the brainstem differs from aneurysmal SAH in its clinical course, and in distribution and severity of bleeding on CT. This could be recognized as a new clinical entity and could be called benign SAH.

Adult↗

PubMed1992

Isolation and some properties of a 34-kDa-membrane protein that may be responsible for ribosome binding in rat liver rough microsomes.

We have isolated, by hydroxyapatite chromatography with a non ionic detergent and a high salt concentration, a non-glycosylated, membrane protein with a relative molecular weight of 34 kDa that had previously been found to be a major constituent of the membrane protein fraction showing ribosome-binding activity derived from rat liver rough microsomes (RM). The isolated 34 kDa protein (p34), when incorporated into a liposome model membrane, exhibited significant binding activity toward ribosomes, its binding properties being similar to those observed with intact RM. Immunochemical analyses using antibodies directed against p34 suggested that it is a membrane-embedded RM surface protein, which is specifically localized in ribosome-attached organelles and widely distributed among mammalian tissues. These results would constitute evidence that p34 is a likely candidate for an RM ribosome-binding protein.

Animals↗

PubMed1992

Choroid plexus arteriovenous malformations.

Among 24 arteriovenous malformations (AVMs) involving the choroid plexus, 11 were plexal type AVMs predominantly located in the choroid plexus of the lateral ventricle, and 13 were parenchymal type AVMs mainly situated in the paraventricular cerebral parenchyma. 83% of all AVMs involved both the choroid plexus and the paraventricular cerebral parenchyma. Most cases presented with intracranial hemorrhage, particularly intraventricular hemorrhage. The most serious surgical problem was a small residual nidus unrecognized at the initial operation causing postoperative hemorrhage. Five parenchymal type AVMs presented residual niduses in the choroid plexus, causing death in two cases. Two plexal type AVMs resulted in residual AVMs supplied by the cisternal segment of the anterior choroidal artery, situated in the medial temporal lobe. To prevent postoperative hemorrhage from a small residual nidus, immediate postoperative angiography while the patient is still under general anesthesia should be performed to identify any residual nidus.

Adolescent↗

PubMed1992

An analysis of the venous drainage system as a factor in hemorrhage from arteriovenous malformations.

The authors studied the venous drainage system and its impairment in relation to risk of hemorrhage in 108 cases of supratentorial arteriovenous malformation (AVM). The proportion of AVM's undergoing hemorrhage (hemorrhagic rate) was calculated in relation to: 1) the number of draining veins (one, two, or three or more); 2) the presence or absence of impairment in venous drainage (severe stenosis or occlusion in draining veins); and 3) the location of draining veins (deep venous drainage alone, superficial venous drainage alone, or a combination of the two). Statistical analysis demonstrated that AVM's with the following characteristics had a high risk of hemorrhage: 1) one draining vein (hemorrhagic rate 89% in 54 patients); 2) severely impaired venous drainage (hemorrhagic rate 94% in 18 patients); and 3) deep venous drainage alone (hemorrhagic rate 94% in 32 patients). The present study suggests that the venous drainage system of AVM's is significantly associated with the risk of hemorrhage of these lesions. Therefore, careful preoperative angiographic evaluation of the venous drainage system is mandatory for decision making in the management of patients with AVM's.

Cerebral Hemorrhage↗

PubMed1992

[Fundus hemorrhage in patients with intracranial hemorrhage caused by cerebrovascular disease--its clinical significance].

To clarify the significance of fundus hemorrhage in the acute stage of intracranial hemorrhage due to cerebrovascular disease (HCVD), the incidence of such hemorrhage (retinal, preretinal, and subhyaloid hemorrhage) was examined and its correlations with the severity of the disturbance of consciousness and the prognosis were investigated. Two hundred sixteen HCVD patients with intracranial hemorrhage were the subjects of this study, including 87 cases of subarachnoid hemorrhage (SAH), 60 cases of hypertensive intracerebral hemorrhage (HICH), 54 cases of arteriovenous malformation (AVM), and 15 cases of Moyamoya disease. Fundus hemorrhage was recognized in 41 cases of SAH (47%), 5 cases of HICH (8%), 3 cases of AVM (6%), and 2 cases of Moyamoya disease (13%). The incidence of fundus hemorrhage was significantly higher in SAH than in the other type of HCVD associated with intracranial hemorrhage. Among patients with severe disturbance of consciousness (JCS 100-300), fundus hemorrhage was recognized in 69% with SAH, 13% with HICH, 17% with AVM, and none with Moyamoya disease. Therefore, patients with both fundus hemorrhage and severe disturbance of consciousness in the acute stage are most likely to have SAH, but HICH and AVM should be also taken into consideration. In patients with slight disturbance of consciousness (JCS 0-30), fundus hemorrhage was only noted in SAH (27%) and not in other types of HCVD associated with intracranial hemorrhage. Thus, SAH is highly likely to be the primary HCVD associated with intracranial hemorrhage, if we recognize fundus hemorrhage in patients with slight disturbance of consciousness in the acute stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Hemorrhage↗

PubMed1992

[The neurological outcome in patients with acute cervical spinal cord injury].

UNLABELLED: Twenty-three patients (twenty males and three females) with acute cervical spinal cord injury were cared for within a defined protocol and followed for 14 to 589 days (mean. 133 days). We evaluated the relationship between neurological recovery and neurological examination, myelography (MLG), CT-myelography (CTM) on admission. All of them were admitted to Kitasato University Hospital within 24 hours after injury. Thirteen of the 23 patients had complete injury, and the others had incomplete injury. RESULT: Four factors were found to be related to neurological recovery. They included: 1) complete injury; 2) areflexia; 3) cord swelling on CTM; and 4) complete block on MLG. Fourteen of 15 patients who had at most two of the four factors improved. But, no patients with three or four factors improved. CONCLUSION: These four factors have been recognized as indicators of bad neurological outcome. However, our result indicates that by our result, improvement of neurological function can be expected in patients affected by only one or two of these four factors. In other words these four factors have prognostic value for predicting the neurological outcome after acute cervical spinal cord injury.

Acute Disease↗

PubMed1991

Capsular and thalamic infarction caused by tentorial herniation subsequent to head trauma.

Five patients (4 male and 1 female) were observed to have capsular and thalamic infarction ascribed to descending transtentorial herniation (DTH) caused by head injury. A lucid interval immediately after the trauma and the presence of an epidural hematoma (EDH) characterized all five cases. At the time of hospitalization consciousness was seriously impaired and signs of cerebral herniation were apparent. Two to four days after the trauma, low attenuation in the computed tomography (CT) images pinpointed intracerebral damage in the anterolateral part of the thalamus and in the internal capsule on the same side as that of the EDH in three patients, and in the other two patients bilateral thalamic and capsular damage was noted. The low attenuation implicated the perforating arteries, that is the anterior thalamoperforating and anterior choroidal arteries, suggesting infarcted regions caused by occlusion of these arteries. Findings in the present study suggest that arterial occlusion in closed head injury may result from DTH. Moreover, infarction may be attributed to the delayed effects of injury.

Adult↗

PubMed1991

Comparative efficacy of acid reflux inhibition by drug therapy in reflux esophagitis.

The advent of histamine H2 receptor antagonists (H2-RA) has allowed the treatment of reflux esophagitis (RE) to be controlled over a relatively long term. The authors have experienced some cases resistant to H2-RA, but it was revealed that these cases can be successfully treated with proton pump inhibitors. It has been suggested that esophagogastric dysmotility can lead to RE. RE has been treated for many years by using GI-prokinetic agents, which theoretically inhibit acid reflux and improve esophageal acid clearance. In order to compare the effects on acid reflux of an H2-RA (famotidine), a proton pump inhibitor (omeprazole) and a GI-prokinetic agent (cisapride), we measured the 24-hour pH in the esophagus and stomach simultaneously, before and after treatment in 17 patients with RE. It was found that the proton pump inhibitor was the most effective drug for inhibiting esophageal acidification, followed by famotidine and then cisapride. Furthermore, we found that cisapride often actually exacerbated acid reflux. The differences in inhibitory effects on acidification allowed us to draw conclusions regarding the treatment of RE. It was concluded that the stronger the inhibitory effect of a drug on acid secretion, the more useful it was in the treatment of RE. The GI-prokinetic drug did not inhibit acid reflux as much as we had expected.

Adult↗

PubMed1991

Fluctuating CPAP (F-CPAP) versus conventional CPAP (C-CPAP) in dogs with blood aspiration.

Fluctuating CPAP(F-CPAP) is a combination of spontaneous ventilation and fluctuating PEEP, in which end-expiratory pressure (EEP) is periodically changed within a certain range. In a dog model with localized lung injury induced by the aspiration of non-heparinized blood (2 ml.kg(-1) body weight), we carried out a comparative study of the effects of F-CPAP in which the EEP was cyclically changed from 4 to 12 cmH(2)O with periods of 10 min and those of conventional CPAP with a fixed EEP of 8 cmH(2)O (C-CPAP), on hemodynamics and pulmonary oxygenation. The blood aspiration produced significant increases in the intrapulmonary shunt (Qsp/Qt), the alveolar-arterial difference of partial pressure of oxygen (A-aD o(2)), and the respiratory rate (RR). Although both F-CPAP and C-CPAP reduced Qsp/Qt and A-aD o(2) and RR, 7 dogs treated with F-CPAP showed a significantly greater recovery of Qsp/Qt and A-aD o(2) than 7 dogs treated with C-CPAP. There were no significant differences in hemodynamic variables between the two groups. These results suggest that F-CPAP is more useful in the treatment of some kinds of hypoxic respiratory failure due to uneven distribution of lung injury.

Journal Article↗

PubMed1991

Effects of portal vein occlusion on myocardial contractility.

We studied canine left ventricular contractile performance following 15 min of portal vein occlusion by analyzing the end-systolic pressure diameter relationship (ESPDR) which many investigators have reported as being independent of changes in preload and afterload but sensitive to changes in ventricular contractility. Portal vein occlusion for 15 min decreased the mean arterial pressure, left ventricular peak systolic pressure, and cardiac index, while the release of the occlusion gradually increased these values, although it did not restore them to the control values. The systemic vascular resistance index increased during portal vein occlusion and returned to the control values after release. Left ventricular end diastolic diameter decreased during portal clamping and returned to the control values after release. ESPDR and percent shortening were not significantly changed during or after portal clamping. These results indicate that the decrease in blood pressure during portal vein occlusion was not due to a reduction in myocardial contractility but rather was due to a reduction in preload.

Journal Article↗

PubMed1991

Hemorrhagic venous infarction after excision of an arteriovenous malformation: case report.

A case of arteriovenous malformation (AVM) in which postoperative hemorrhagic infarction developed, probably because of occlusion of the former draining veins, is reported. The hemorrhage developed in the temporal lobe 3 days after the initial operation and was located in the immediate vicinity of the site of the AVM. The following findings suggest that the postsurgical hemorrhage probably resulted from a venous thrombosis: 1) no evidence of residual AVM; 2) delayed onset of the hemorrhage, inconsistent with the time course of a hemorrhage developing according to the breakthrough theory or with insufficient hemostasis with a high-pressure afterload; 3) good correlation between the location of the hemorrhage and the occlusion of the draining veins; and 4) multifocal hemorrhage affecting both the gray matter and the subcortical white matter. Postoperative hemorrhagic infarction caused by thrombosis in the draining veins is rare, but it should be considered as a distinct postoperative complication after removal of an AVM.

Cerebral Hemorrhage↗

PubMed1991

[Pharmacokinetic basis of mannitol administration in the treatment of raised ICP].

To study the most effective way of mannitol administration for the treatment of raised intracranial pressure (ICP), pharmacokinetics of mannitol were analysed, and the relationship among mannitol concentration, serum osmolality and changes of intracranial pressure (ICP) were examined in cats. 10%, 20% and 30% of mannitol were made and intravenously administrated with the same volume and speed (0.667 ml/kg/min) for 15 minutes to each mannitol concentration group of cats. Sequential changes of ICP were monitored and serial mannitol concentration, serum osmolality and electrolytes were then performed. Changes of mannitol concentration showed a biexponential curve and best fitted to the two-compartment model analysis. There was a strong positive correlation (r = 0.9286) between mannitol concentration and extrinsic serum osmolality. The disposition of mannitol in cats was similar to that which had been reported in dogs and humans. The distribution half-time was faster in 30% mannitol, but the elimination half-time was similar in all groups. The integrated values of mannitol concentration difference between the central (Cc) and the peripheral compartment (Pc) were greatly correlated with the changes of ICP reduction during mannitol administration (for 15min). The time to vanish the mannitol concentration difference between Cc and Pc showed strong reverse correlation with the time to reach the lowest ICP level. The result indicates that the more rapidly mannitol was administrated, the more rapidly the concentration difference between the two compartments was created, and, the higher the effective osmolality was developed, then, the more profound and prolonged ICP reduction can be obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

[A case of post-traumatic medial longitudinal fasciculus syndrome].

Medial longitudinal fasciculus (MLF) syndrome recognized 2 days after a head injury is described. The patient was a 48-year-old man who had fallen from a ladder about 3m high. On his admission, scalp contusion on the left occipital area was noticed. Neurological examination revealed no neurological abnormalities except slightly disturbed consciousness. Plain skull X-ray films demonstrated a lineal skull fracture of the left occipital bone. Computed tomographic (CT) scans showed a slight subarachnoid hemorrhage within the bilateral sylvian fissures, but no parenchymal contusion in the brain stem was observed. On the 2nd day, when the patient regained full consciousness, impairment of adduction of the right eye and a fine nystagmus of the left eye on left lateral gaze were recognized. Convergence was intact. Right side MLF syndrome was diagnosed. This syndrome gradually disappeared followed by the initial improvement of adduction of the right eye, and the patient had completely recovered about 20 days after the head injury. Three major mechanisms leading to MLF syndrome caused by head injury are reported in the literature. They are: (1) primary brain stem injury, (2) secondary brainstem injury by trans-tentorial herniation, and (3) circulatory disturbance of perforating branches of the vertebro-basilar artery due to shearing force. In our case, the slightly disturbed consciousness at the time of the head injury indicates that this syndrome was not brought on by primary or secondary brain stem injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Injuries↗

PubMed1990

Neurinoma of the oculomotor nerve--case report.

Only 10 cases of oculomotor nerve neurinoma have been reported previously. The authors report the rarity of a neurinoma originating from Schwann cells of the oculomotor nerve. The diagnosis was based on the initial sign of oculomotor nerve paresis without involvement of other cranial nerves, neuroradiological and surgical findings, and histological features of the specimen obtained at surgery.

Aged↗

PubMed1990

Retrograde thrombosis of feeding arteries after removal of arteriovenous malformations.

Five cases of retrograde thrombosis of former feeding arteries after removal of an arteriovenous malformation (AVM) are reported. The clinical features of these patients were studied and compared to those of 71 patients without this complication. The following characteristics were found to correlate with retrograde thrombosis: 1) advancing age of the patient; 2) large AVM size; and 3) markedly dilated and elongated feeders. It is suggested that the slow flow in the former feeding arteries that was observed immediately after AVM removal and pathological changes in these vessels due to long-standing hemodynamic stresses contributed to the development of retrograde thrombosis. Neurological manifestations related to retrograde thrombosis were noted in three of the five cases. Although infrequent, this complication should be considered as a serious possibility following removal of an AVM.

Adolescent↗