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Biomedical subjects

M Shimoda

Publications and source records attributed to M Shimoda.

At least 163 records · Page 9Linked to original sources

Time course of CSF lactate level in subarachnoid haemorrhage. Correlation with clinical grading and prognosis.

Cisternal and/or ventricular cerebrospinal fluid (CSF) and arterial blood lactate and acid-base balance were measured serially in 38 patients with aneurysmal subarachnoid haemorrhage (SAH). Based on daily clinical assessment, the patients and accordingly the samples were divided into two groups according to the grading of the World Federation of Neurosurgical Societies (W.F.N.S.). In cisternal CSF, samples of Grade III-V showed significantly higher lactic acidosis than those of Grade I-II. The time course of lactate and pH in poor prognosis groups had a significant tendency of lactic acidosis, especially on the 5th, 6th, 7th day after SAH. Ventricular CSF lactate increased even without CSF acidosis in Groups III-V. Measurement of CSF lactate, especially from the cisterna magna is useful as an indicator of prognosis and changes of intracranial environment following SAH.

Acid-Base Equilibrium↗

Atrial natriuretic polypeptide in patients with subarachnoid haemorrhage due to aneurysmal rupture. Correlation to hyponatremia.

Measurement of plasma alpha-humanANP (ANP) and antidiuretic hormone (ADH) in 28 cases with aneurysmal subarachnoid haemorrhage (SAH) was carried out, and then compared with control subjects who were infused with hypertonic saline. In cases with hyponatremia (HN), statistical correlation between control subjects and cases without HN was not evident with regards to ANP and plasma osmolality (Posm), excreted fraction of filtrated sodium (FENa) and urinary Na/K. Furthermore, they secreted supernumerarilly in spite of HN. Cases with HN were further subdivided into two groups, they were those cases with negative total sodium balance at the time of appearance of HN, and those cases without total negative sodium balance. In the former, central venous pressure had a tendency to decrease, however, secretion of ANP and ADH was statistically not different in either groups. It appears that ANP regulated urinary sodium excretion against an osmotic or sodium load acts as a maintenance of homeostasis as an osmotic regulator. Cases with HN in which secretion of ADH was physiological, ANP secreted supernumerarilly in spite of hypoosmonaemia and hypovolaemia. Our findings may contribute to a better understanding of the pathophysiological processes leading to hyponatremia in cases with cerebral disorders, and may help to improve the treatment possibilities.

Adult↗

Decreased plasma albumin concentration results in increased volume of distribution and decreased elimination of midazolam in intensive care patients.

The pharmacokinetic parameters of 16 patients in the intensive care unit, sedated with midazolam, were evaluated. A large variation was observed in the plasma concentration of midazolam and between the plasma concentration of midazolam and its metabolite 1-hydroxymethylmidazolam glucuronide. The plasma albumin concentration governs the volume of distribution of midazolam. Decreased plasma albumin concentration (25 gm/L) results in an increased volume of distribution and a decreased elimination rate of midazolam. The observed plasma concentration ratio between the parent drug and its metabolite 1-hydroxymethylmidazolam glucuronide is governed by the variables of protein binding, the metabolic rate of midazolam, and the renal clearance of the glucuronide metabolite itself (which can be considered as a measure of the kidney function of the patient).

Adult↗

Nonlinear pharmacokinetics of intravenous sulphadimethoxine and its dosage regimen in pigs.

The time courses of the total (Ct) and unbound plasma (Cf) concentration after the i.v. injection of 20, 50 and 100 mg/kg of sulphadimethoxine (SDM) were examined in pigs. The area under the Ct-time curve per unit dose decreased dose-dependently. Vdarea and total body clearance of Ct increased dose-dependently. The concentration-dependent plasma protein binding of SDM was evident after 50 and 100 mg/kg. The time courses of Cf en Ct after 3 doses were analyzed by a one compartment open model with nonlinear plasma protein binding. The agreement between calculated curves of Cf and Ct and the observed values, and relative constancy of pharmacokinetic parameters were obtained over 3 doses. These results suggested that the nonlinear pharmacokinetics of SDM was caused by saturable plasma protein binding. The multiple i.v. dose of SDM was based on the dosage regimen using the nonlinear pharmacokinetic model (50 mg/kg, 24 hour interval, 4 days). The observed Cf was maintained in the intended range by the dosage regimen. Therefore, the dosage regimen based on the nonlinear pharmacokinetics may allow the unbound concentration after i.v. injection of SDM in pigs to be controlled.

Animals↗

An appropriate ingestion volume of oral sulfa drug suspension in pigs.

The influence of ingested volume of a sulfa drug suspension, sodium sulfamonomethoxine (SMMNa), on the oral pharmacokinetics was studied in pigs, with regard to bioavailability and gastric emptying. Eighteen pigs, weighing 30-70 kg, were used. Phenol red solution was used for the evaluation of gastric emptying study. SMMNa suspension was used for pharmacokinetic study. Both of these fluids were administered by natural swallowing. Three experimental groups were constructed: G-I; 5 ml/kg of the test fluids to starved animals, G-II; 5 ml/kg of the test fluids to fed animals and G-III; 20 ml/kg of the fluids to fed animals. The glucose glycine electrolyte solution (GGES) was used as the vehicle for both the compounds. Six pigs, having duodenal cannula, were used for the study of gastric emptying. The gastric emptying rate was rapid in G-I, relatively rapid in G-III, and slow and variable in G-II. In agreement with the result of gastric emptying study, the values of Cmax and tmax were high and rapid in G-I, relatively high and rapid in G-III, and low and slow in G-II. Accordingly, the voluminous ingestion of drug suspension can facilitate the gastric emptying, in turn may make the oral absorption of the drug rapid-and-uniform. The 20 ml/kg volume of sulfa drug suspension may practically be recommended for the oral administration in pigs.

Administration, Oral↗

[Nasal cavity paraganglioma with intracranial extension. Case report].

A 58-year-old male was admitted following an episode of unconsciousness. Nine years prior to this, he had undergone surgery and radiation therapy for a nasal tumor. Subsequently, he had undergone surgical excision of recurrent nasal tumors and metastases to the cervical lymph nodes. The final pathological diagnosis was paraganglioma. On admission, he had no neurological deficit other than anosmia. Laboratory studies showed no abnormalities in urinary concentrations of vanillylmandelic acid or catecholamines. Computed tomography (CT) demonstrated a calcified, heterogeneously enhanced mass in the anterior ethmoid sinus and bilateral frontal fossa. Cerebral angiography revealed a mesh-like tumor stain. Through a bifrontal craniotomy the intracranial tumor was totally removed. It was hypervascular and clearly demarcated from the surrounding cerebral tissue. The pathological diagnosis was paraganglioma without malignant features. Radiation therapy was administrated postoperatively at a total dose of 5060 rads, and follow-up CT showed regression of the ethmoid sinus tumor. As of 2 years postoperatively, the tumor has not recurred.

Brain Neoplasms↗

Indications for cisternal drainage in conjunction with early surgery in ruptured aneurysms and timing of its discontinuation.

The efficacy of cisternal drainage in association with early aneurysmal surgery remains highly controversial. The authors attempted to clarify the indications for this procedure and the proper timing of drainage removal in a series of 205 patients with no evidence of intracerebral hematoma who underwent surgical obliteration of bleeding aneurysms within 72 hours after subarachnoid hemorrhage. The 136 patients in whom cisternal drainage was performed constituted Group A and the remaining 69 patients Group B. The acid-base balance and lactate concentration were measured serially in cisternal cerebrospinal fluid (CSF) and arterial blood of 33 patients. Subarachnoid blood demonstrated by computed tomography (CT) was graded according to the system of Fisher et al. The outcome at 6 months did not differ significantly between Groups A and B among patients of preoperative CT grade 2 and clinical grades I-II. However, among patients of CT grade 3 or clinical grade III, those in Group A had better outcomes. The rates of symptomatic vasospasm in Groups A and B were 39.7% and 40.6%, respectively. However, persistent vasospasm was more frequent in Group B (11.8% vs. 26.1%), particularly in CT grade 3 patients. Ventricular enlargement was more prevalent in Group A (33% vs. 17%). CSF pH higher than arterial pH after the 7th postoperative day was associated with a poor outcome and was fairly well correlated with a rise in CSF HCO3- and a fall in CSF PCO2. CSF lactate increased with clinical deterioration but was not well correlated with preoperative CT findings, total volume of CSF outflow, or prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[Peripheral superior cerebellar artery aneurysm. Case report].

The patient, a 37-year-old female, was hospitalized with a severe headache. Neurological examination on admission revealed no deficits except for neck stiffness and somnolence. Computed tomography showed a subarachnoid hemorrhage, which was especially prominent in the supracerebellar and quadrigeminal cisterns, but demonstrated no ventriculomegaly. Cerebral angiography on admission revealed no apparent abnormalities, but repeat angiography 8 days later disclosed a saccular aneurysm (2 X 3 mm) arising from the hemispheric branch of the left superior cerebellar artery (SCA). Three days after admission, the patient developed cerebellar dysarthria, which was assumed to be due to vasospasm. On the 24th day after admission, the aneurysm was successfully clipped through the infratentorial-supracerebellar approach. The postoperative course was uneventful and the patient was discharged with no neurological deficit. Nineteen other cases of peripheral SCA aneurysm have been reported in the literature. The presence of this type of aneurysm should be considered in patients who are fairly young and have focal neurological signs, such as third or fourth nerve palsy and/or cerebellar dysfunction. The prognosis for such patients is good, except in cases in which the neurological status is poor at the onset.

Adult↗

[Low-dose dopamine treatment of patients in nonketotic hyperosmolar hyperglycemic coma].

In the acute neurosurgical setting, nonketotic hyperosmolar hyperglycemic coma (NHC) is thought to be caused by cerebral dehydration therapy and administration of steroids, glycerol, or mannitol. The mortality of this complication is reportedly very high, and is due to acute renal and/or cardiac failure. The authors evaluated the effect of low-dose dopamine (LDD; 1 to 5 micrograms/kg/min) administration in 10 patients with this syndrome. LDD was given to five patients. In these cases, hypovolemia was treated under central venous pressure monitoring with an iso-osmolar hyponatremic lactate solution given in a volume greater than the urine output. After the hypovolemia was corrected, the fluid was administered in a volume equal to the urine output until the serum osmolarity was normalized. In the five patients not given LDD, a large quantity of hypotonic solution was rapidly administered. In all patients treated with LDD, the urinary sodium increased and the urinary output stabilized. Consequently, the excess urea-nitrogen and serum sodium were quite easily washed out. The total net intake volume for the normalization of serum osmolarity was small and the duration of treatment was much shorter than that of patients not treated with LDD. The LDD regimen was not associated with complications, such as aggravation of cerebral edema, renal failure, or cardiac failure. On the other hand, three of the five patients not given LDD died of acute renal and/or cardiac failure without normalization of laboratory data. It is emphasized that this therapy, which results in beta-effect of catecholamine, sodium diuresis, and increased renal blood flow, is a practical means of managing acute neurosurgical cases complicated by NHC.

Adult↗

Application of a monoclonal antibody to a comparative study of alpha-lactalbumins from various species.

A monoclonal antibody to bovine alpha-lactalbumin was prepared and purified. The binding ability of alpha-lactalbumin from different species (cow, goat, giraffe, horse, pig, human, monkey, and guinea pig) was examined by a competitive radioimmunoassay. The order in strength of the binding affinity was cow goat, giraffe, horse, cynomolgus monkey and human, pig, and guinea pig. The order of evolutional divergence calculated from the amino acid composition was cow, goat, giraffe, horse, pig, guinea pig and human, and monkey. The orders in both cases were similar. Hence, it is suggested that immunological divergence as deduced by a monoclonal antibody is likely to be close to the evolutional divergence of alpha-lactalbumin.

Amino Acids↗

[Case report: hemiballism due to a putaminal cavernous hemangioma].

A rare case of reversible hemiballism due to putaminal pathological process in a 51-year-old woman is described. She was hospitalized for evaluation of hemiballism and muscle weakness on the left side. A cranial computed tomography scan demonstrated a high density lesion in the right putamen with enhancement on delayed scan. Angiographic examination revealed no apparent abnormalities. Magnetic resonance imaging with T1 weighted showed a isodense lesion in the right putamen, while T2 weighted image revealed a ring like low signal area around a high signal lesion. These findings were compatible with the diagnosis of cavernous hemangioma. In order to establish the final diagnosis, CT-guided stereotaxic biopsy was carried out. But histological specimen showed only gliosis and calcification. Immediately after the biopsy, a small hemorrhage took place in the right putamen extending to the head of caudate nucleus head. Following this episode, hemiballism ceased, however, it gradually returned along with absorption of hemorrhage. The speculated pathophysiology of this on-and-off hemiballism was as follows; it initially developed as the result of suppression of inhibitory fibers from the striatum to the pallidum by a minor hemorrhage of putaminal cavernous hemangioma, and ceased by declining the activities of the pallidum due to interruption of excitatory fibers from the thalamus and the cortex to the striatum.

Brain Neoplasms↗