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Biomedical subjects

M Shimoda

Publications and source records attributed to M Shimoda.

At least 181 records · Page 10Linked to original sources
PubMed1988

Pharmacokinetics of oral sulfa drugs and gastric emptying in the pig.

The plasma pharmacokinetics of sulfamonomethoxine (SMM) and sulfamethazine (SMZ) in the pig were examined after the oral and intravenous (i.v.) administration of the sodium salt solutions. Eight pigs from a commercial breed and 8 Goettingen minipigs were used. Both the Cmax and tmax of SMM and SMZ ranged widely. A flipflop phenomenon was found after the SMM solution but not after the oral SMZ. Duodenal cannulae were inserted in 5 pigs. The SMM solution and the SMM suspension were directly injected into the duodenum through the duodenal cannula. Both Cmax values were in a narrow range. Both tmax values were in a narrow range and were reached within 30 min. There was no flipflop phenomenon. Gastric emptying in the pig was examined using duodenal cannulated pigs. Phenol red solution and SMM suspension were administered orally. The time courses of gastric emptying of the two markers were nearly coincident and they approximated an exponential decrease. The times required for the 50% passage of the marker from the stomach ranged widely between 0.06-7.7 h, which may cause the variation in the Cmax and tmax of the sulfadrugs after oral administration. The kappa-GE (rate constant of the terminal phase of gastric emptying) also ranged widely. Nine kappa-GE values among 22 were smaller than the minimum value of the SMM kappa el values, which may cause the flipflop phenomenon of the oral SMM. In contrast, all of the kappa el values of SMZ were smaller than the minimum value of kappa-GE. And no flipflop phenomenon was found after the oral SMZ. Accordingly, the pharmacokinetics after the oral sulfonamides solution may be intimately influenced by the gastric emptying.

Administration, Oral↗
PubMed1988

Role of deacetylation in the nonlinear pharmacokinetics of sulfamonomethoxine in pigs.

The role of deacetylation in the pharmacokinetics of sulfamonomethoxine (SMM) in pigs was studied using 6 Goettingen minipigs and a pig from a commercial breed. The rapid decrease of plasma concentration of the parent compound followed by the rapid increase of plasma concentration of the deacetylated metabolite, SMM, was observed after an i.v. injection of N4-acetylsulfamonomethoxine (AcSMM; 10 mg/kg). The concentration of the metabolite, SMM, was greater than that of AcSMM and after reaching peak, both compounds decreased in parallel on a semilogarithmic graph. On the other hand, the acetylated compound of SMM (AcSMM) appeared in the plasma and reached peak after an i.v. injection of SMM. After reaching the peak, both SMM and AcSMM decreased in parallel. The slopes of the terminal phases of SMM and AcSMM after both injections showed no significant difference. After the i.v. injection of a high dose of SMM (100 mg/kg), a nonlinear pharmacokinetics profile with capacity limited elimination type of SMM was observed. The concentration of plasma AcSMM increased rapidly and the parallel decrease of SMM and AcSMM was observed in both nonlinear and linear phases, while the renal excretion of AcSMM was saturated in the nonlinear phase. The results suggest that the deacetylation in pigs is so strong that it largely affected the pharmacokinetics of SMM in both high and low doses. In spite of the saturation in renal excretion of the main metabolite, AcSMM, after the high dose, the profile of the parallel decrease remained unchanged, which may be due to the rapid conversion of the excess AcSMM to SMM. The converted SMM was added to the existing plasma SMM. As a result, the nonlinear pharmacokinetics of SMM may have occurred after a high dose of SMM in pigs.

Acetylation↗
PubMed1988

[Renal protection in acute neurosurgical diseases--effect of a low dose dopamine with reference to acute renal failure and hypernatremia in patients with dehydration].

The authors reviewed the effect of low dose dopamine administration (1-5 micrograms/kg/min) in neurosurgical patients with acute renal failure (5 cases) or hypernatremia (7 cases) in whom cerebral dehydration therapy for intracranial hypertension was thought to be causative of these disorders. Cases with hypernatremia (serum sodium over 155 mEq/l) were considered in the stage of impending acute renal failure as in the majority of cases serum creatinine levels were mildly elevated while urinary sodium was markedly diminished. Associated with systemic hypovolemia, in cases with acute renal failure (with serum creatinine over 3.5 mg/dl and urinary output of less than 20 ml/hr for more than 4 hour duration) the urinary sodium levels were less than 20 mEq/l. In all the cases treated by low dose dopamine, urinary output and sodium increased within 6 hours and in the following 24 hours stabilized urinary output with its elevated sodium (some 100 mEq/l) was obtained. As the result, elevated urea-nitrogen or serum sodium was rather easily washed out and the patients were kept adequately hydrated afterwards. Any complications such as aggravation of cerebral edema or convulsive disorder were not associated with this regime. The authors, therefore, would emphasize that low dose dopamine administration resulting in sodium diuresis and increase in renal blood flow is a practical way of method in treating patients with hypernatremia or acute renal failure caused by hyperosmolar agent infusion in their acute stage.

Acute Kidney Injury↗
PubMed1988

[A case of multiple superficial temporal artery pseudoaneurysms following craniotomy].

A case of multiple superficial temporal artery (STA) pseudoaneurysms following craniotomy is reported and a review of the literature is made. The patient was a 17-year-old male who was hospitalized as he developed right hemiparesis 4 hours after golf ball injury to the left temporal region. He had been diagnosed as hemophilia A one year prior to the injury. CT scan showed right parietal intracranial hematoma with mass effect when he was submitted to emergency craniotomy. At surgery a linear scalp incision was made over the left temporal area after high factor VIII concentrates (con-VIII), 2,000 units, were administered. His postoperative course was uneventful and hemiparesis improved substantially, however two pulsatile masses along the incision scar over the scalp were noticed some 40 days after the hematoma removal. There was another pulsating mass in the left wrist where an arterial cannulation was made at the time of craniotomy. Selective angiograms showed two left STA pseudoaneurysms and left radial pseudoaneurysm was also demonstrated. The left STA was embolized with Gelfoam pieces through catheterization after administration of con-VIII, and the radial artery aneurysm was surgically resected. There was no evidence of recurrence of these lesions during the follow-up period of eight months. Among over 130 cases of STA pseudoaneurysms reported, there was no case with hemophilia and also no such a case described which developed after craniotomy on reviewing the literature. And it was proved that con-VIII has enabled a patient to tolerate embolization procedure through catheterization.

Adolescent↗
PubMed1987

Infantile acute subdural hematoma.

A retrospective analysis of the infantile acute subdural hematoma was made with special reference to its pathogenesis. In 11 of 15 cases, the hematomas were bilateral or a contralateral subdural fluid collection was present. In 7 of 11 patients who underwent operation the collection was bloody fluid and/or clotted blood. In 3 patients, a subdural membrane, as seen in adult chronic subdural hematoma, was found. In only 1 patient with unilateral hematoma was clotted blood present without subdural membrane. The thickest collection of clotted blood was in the parasagittal region. It is postulated that in most cases hemorrhage occurs after minor head injury, from the bridging veins near the superior sagittal sinus, into a pre-existing subdural fluid collection such as chronic subdural hematoma or subdural effusion with cranio-cerebral disproportion, and that infants without intracranial disproportion are unlikely to have acute subdural hematoma caused by minor head injury.

Acute Disease↗
PubMed1987

Spontaneous cervical epidural hematoma.

The authors report a case of spontaneous cervical epidural hematoma in a 13-year-old boy who exhibited hematoma recurrence 3 years after the first incidence. A review of the literature indicates very few reports of the recurrence of spinal epidural hematoma.

Adolescent↗
PubMed1987

[Three cases of scalp arteriovenous malformations].

Three cases of scalp arteriovenous malformation (AVM) are presented and the pertinent literature is reviewed. Case 1 was a 50-year-old male who was admitted to hospital with a pulsatile mass involving the right parietal region. Selective angiography revealed a scalp AVM fed by bilateral superficial temporal and right occipital arteries. The AVM was embolized with Gelfoam pieces through catheterization and there was no evidence of recurrence of the lesion after follow-up period of three years. Case 2 was a 25-year-old male who was noticed to have a birth mark in the left occipito-parietal region and was hospitalized with a pulsatile gradually expanding mass after an episode of minor trauma in the same region. Selective angiography revealed a cirsoid type scalp AVM fed by bilateral superficial temporal and occipital arteries, and the authors performed a total resection of the mass because of selective Gelfoam embolization was not successful. Case 3 was a 49-year-old male who was hospitalized with the chief complaints of left tinnitus and pulsatile left supra-auricular mass. There was no history of trauma. Selective angiography revealed a scalp AVM fed by the left superficial temporal and occipital arteries and the authors performed a selective Gelfoam embolization and this was successful, but three months later, the AVM recurred and mainly fed by instead this was the left posterior auricular artery. Preoperative selective Gelfoam embolization followed by a total resection of the AMV with minimal blood loss.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Possible active tubular secretion of sulfamonomethoxine and its metabolites in pigs.

The effect of probenecid on the plasma kinetics of sulfamonomethoxine (SMM) was examined in conscious pigs. A linear kinetic dose of SMM (10 mg/kg) was injected with or without probenecid. Probenecid (25 mg/kg, i.v.) was injected immediately before SMM injection and against at 1, 2, 3, 4 and 6 h later. The AUCs of SMM and of the acetylated compound of SMM (AcSMM) in probenecid injected animals were significantly larger when compared with those of non-injected animals (p less than 0.05). Next, possible active secretion from the renal tubule of SMM and its metabolites was examined using probenecid and pyrazinoate. Ten commercial pigs with ureter cannulae were used under anesthesia. The plasma concentration of SMM and AcSMM was maintained at a steady state by a priming dose of SMM (5 mg/kg, i.v.) followed by sustaining infusion (4 micrograms/kg/min). Renal clearance of AcSMM was suppressed by bolus injection of probenecid (25 mg/kg), but that of SMM was not. The renal excretion of a water soluble metabolite was suppressed by probenecid. No marked changes in renal excretory kinetics were found by pyrazinoate injection (12.5 mg/kg, i.v.). Consequently, the saturation in the active tubular secretion of AcSMM may play an important role in the nonlinear pharmacokinetics of SMM in pigs.

Acetylation↗
PubMed1986

Contribution of renal active secretion in renal excretion of N4-acetylsulfamonomethoxine in conscious pigs.

The contribution of renal active tubular secretion of N4-acetylsulfamonomethoxine (AcSMM) in renal excretion was examined using 3 conscious pigs with permanent ureter cannulae. AcSMM was the main metabolite of sulfamonomethoxine (SMM) in pigs. When AcSMM (100 mg/kg) was intravenously injected, the renal clearance of AcSMM increased with the decrease of AcSMM plasma concentration. Michaelis-Menten kinetics was demonstrated in the renal excretion of AcSMM. It can be concluded that AcSMM is mostly excreted through active tubular secretion. The decrease of renal clearance of AcSMM may be thought as the causal factor of nonlinear plasma kinetics of SMM in pig.

Animals↗
PubMed1986

[A case of central pontine myelinolysis].

A case of central pontine myelinolysis (CPM) following rapid correction of hyponatremia is reported and a review of the literature is made. The patient was a 63-year-old non-alcoholic female who had no liver or kidney diseases in her past history. She was found unconscious after a series of convulsions and was admitted to the hospital. Eighteen months prior to admission, she had a surgery for a ruptured anterior communicating artery aneurysm. Her postoperative course was uneventful except for an urinary incontinence and mild disorientation. She was initially lethargic with conjugate deviation toward right. Nine days after admission, she still remained lethargic, and laboratory studies showed a serum sodium value of 93 mEq/l, serum osmolarity 206 mOsm/l and urine osmolarity 270 mOsm/l when she was clinically diagnosed as having SIADH. She was treated by a strict elimination of water, and administration of sodium, dexamethasone and demeclocycline. In three days, serum sodium was corrected and returned to 137 mEq/l. However, she deteriorated in consciousness and became comatose and developed quadriplegia. CT scans and cerebral angiograms were normal. One month later, another CT scans demonstrated a well-defined hypodensity area in the pons. Brain stem auditory response (BSAR) showed a prolongation of III-V interpeak latency, especially IV-V interval. Her neurological state was essentially unchanged thereafter and she died of septic shock after 12 months' hospitalization. No permission for autopsy was obtained. The clinical course, CT scans and BSAR reported here are indicative of the diagnosis of CPM.

Brain Stem↗
PubMed1985

A marked increase of calcium uptake in the ATP-depleted red cells of patients with iron deficiency.

Calcium (Ca) uptake was markedly increased in ATP-depleted red cells of patients with iron deficiency anemia (IDA) compared to ATP-depleted normal red cells. The extent of increased Ca uptake was related to the severity of iron deficiency as judged by decreased mean cell volume. Moreover, the increased Ca uptake returned to normal levels after oral iron supplementation therapy. The net calcium content of fresh red cells from iron-deficient individuals was the same as in red cells from normal subjects. Sodium influx and ferric ion uptake appeared to be virtually unaffected in the iron deficient red cells.

Adenosine Triphosphate↗
PubMed1985

An increased calcium accumulation in ATP-depleted red cells of the patients with paroxysmal nocturnal hemoglobinuria.

A marked increase in calcium (Ca) uptake (85.5 +/- 39.0 nmoles/ml RBC/2 hr) was observed in ATP-depleted red cells of patients with paroxysmal nocturnal hemoglobinuria (PNH) as compared to ATP-depleted normal red cells (8.0 +/- 2.0). The extent of increased Ca uptake in the PNH red cells was related to the extent of increased sensitivity to complement, as judged by the sugar water test (p less than 0.001) and the acidified serum test (p less than 0.001), and inversely correlated to the decreased activity of red cell acetylcholinesterase (p less than 0.01). The results may indicate that increased calcium uptake in PNH red cells is a possible intrinsic defect of the red cell membranes in the disorder.

Adenosine Triphosphate↗