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Biomedical subjects

O Watanabe

Publications and source records attributed to O Watanabe.

At least 55 records · Page 3Linked to original sources
PubMed1999

Comparison of MR imaging with CT in depiction of tumour extension into the pterygopalatine fossa.

The computed tomography (CT) and magnetic resonance imaging (MRI) results of 30 consecutive patients with tumours in the skull base, and who had abnormalities of the pterygopalatine fossa (PPF) on CT or MRI, were retrospectively compared with respect to visualization of tumour infiltration into the PPF. CT did not depict the abnormalities in the PPF in five patients (17%), while unenhanced T1-weighted MR images depicted tumour infiltration in all patients. Obliteration of PPF fat was better visualized on CT than T2-weighted and proton density weighted MR images, as were bony abnormalities. On MRI, intracranial extension was seen in eight of 25 patients with extracranial tumour. MRI is a sensitive method of demonstrating both tumour infiltration of the PPF and perineural tumour spread.

Adolescent↗
PubMed1999

Strain differences in peripheral-nerve regeneration in rats.

Currently, several strains of rats are used for studies of peripheral-nerve injury and repair. The purpose of this study was to determine if significant differences in regeneration between strains exist that might influence comparison of results and interpretation of scientific conclusions. One outbred (Sprague-Dawley) and four inbred stains (ACI, Wistar-Furth, Lewis, Brown-Norway) were studied. Animals were randomized to one of two experimental conditions, undergoing either posterior tibial nerve transection and repair, or Silastic conduit repair of the posterior tibial nerve (n=6/group). Endpoint evaluations at 6 and 13 weeks included histomorphometry and walking-track analysis. Evidence of excellent regeneration was noted in all rat strains undergoing primary repair. Generally, no statistically significant differences between strains were noted, regardless of endpoint evaluation used in the primary repair group. Nerve regeneration across the conduits was either poor or not present at 6 weeks, with no regeneration at all noted in any animals in the ACI and Brown-Norway groups, and regeneration in only one or two animals in the other strains. At 13 weeks, between three and five animals in each strain showed regeneration, but functional recovery was poor. Overall, few differences in peripheral-nerve recovery appear to exist between rat strains. It seems that uniform conclusions may be drawn regardless of strain used.

Analysis of Variance↗
PubMed1999

Peripheral nerve injection injury with antiemetic agents.

Antiemetics are widely used drugs, frequently administered to alleviate postoperative and postchemotherapeutic nausea and vomiting. While antiemetics do not induce peripheral neurotoxicity when administered systemically, it is not known whether peripheral nerve injury can occur as a result of inadvertent intraneural injection during intramuscular administration. The purpose of this study was to characterize the neurotoxic effect of three commonly used antiemetic agents (promethazine, dimenhydrinate, and prochlorperazine) as compared to saline in the rat sciatic nerve model. Intrafascicular and extrafascicular injection as well as direct application of the antiemetic drugs were performed. Nerves were harvested at 2 weeks postoperatively for histology and morphometry, with an additional sacrifice point at 8 weeks for the intrafascicular injection group. Injection injuries caused by antiemetic drugs differed depending on the agent injected and the location of injection. Extrafascicular injection and direct application caused no damage. Intrafascicular injection caused diffuse axonal injury in the promethazine and dimenhydrinate groups, while prochlorperazine caused only focal injury. Regeneration was prominent at 8 weeks in all intrafascicular injection groups in this rat model. Prochlorperazine thus appears to be less neurotoxic when injected intraneurally and should preferentially be used for intramuscular injections.

Animals↗
PubMed1999

Nicorandil, a potassium channel opener, abolished torsades de pointes in a patient with complete atrioventricular block.

TdP is a serious complication of AV block. We report a case of complete AV block with QT prolongation who had bouts of TdP resistant to lidocaine and isoproterenol. Temporary pacing could not be performed, because insertion of a pacing lead triggered TdP that deteriorated into ventricular fibrillation. Nicorandil, a potassium channel opener, shortened the QT interval and abolished TdP. This may suggest that potassium channel opening drugs are clinically effective against TdP associated with bradycardia-dependent QT prolongation.

Aged↗
PubMed1999

Abrupt exacerbation of acute subdural hematoma mimicking benign acute epidural hematoma on computed tomography--case report.

A 75-year-old male was hit by a car, when riding a bicycle. The diagnosis of acute epidural hematoma was made based on computed tomography (CT) findings of lentiform hematoma in the left temporal region. On admission he had only moderate occipitalgia and amnesia of the accident, so conservative therapy was administered. Thirty-three hours later, he suddenly developed severe headache, vomiting, and anisocoria just after a positional change. CT revealed typical acute subdural hematoma (ASDH), which was confirmed by emergent decompressive craniectomy. He was vegetative postoperatively and died of pneumonia one month later. Emergent surgical exploration is recommended for this type of ASDH even if the symptoms are mild due to aged atrophic brain.

Accidents, Traffic↗
PubMed1999

[Posterior mediastinal diffuse pleomorphic lymphoma].

A 26-year-old man presented with a 38 degrees C fever of undetermined origin in November 1977. His fever subsided in 1 month, but recurred concomitantly with dysphagia on December 10. For this reason, the patient visited our out patient clinic on December 15, and was hospitalized because a mass was found radiographically in the left lower lung field. A contrast-enhanced computed tomographic scan of the chest revealed an irregularly-shaped mass encircling the esophagus. Based on open-lung biopsy findings, the mass was diagnosed as non-Hodgkin's lymphoma, diffuse pleomorphic type. Neither swelling of the superficial lymph nodes nor hepatosplenomegaly was detected, and a bone-marrow aspiration specimen disclosed no atypical cells. Ga scintigraphy found accumulation only in this region, suggesting the posterior mediastinum as the origin of the lymphoma. Reports of non-Hodgkin's primary lymphoma in the posterior mediastinum are rare. Further, to our knowledge, there have been no reports at all on the diffuse pleomorphic type to date. This case was accordingly considered to be of highly informative value.

Adult↗
PubMed1999

[A case of Morgagni's foramen hernia difficult to differentiate from lipoma].

A 61-year-old woman was admitted for chest discomfort. She had been admitted before, in March 1995, because of a lesion detected on chest roentgenograms. At that time, she was given a diagnosis of mediastinal lipoma based on the findings of chest computed tomography (CT) and magnetic resonance imaging (MRI), but was discharged without active intervention due to lack of subjective symptoms. During follow-up, the patient again reported chest discomfort beginning in March 1998. Because chest radiography disclosed. The tumor had enlarged, the patient was admitted to the hospital by our department. Chest MRI disclosed a mass with a signal intensity equal to that of subcutaneous fat in the pericardial space on both T1-weighted and T2-weighted images. Although sagittal images demonstrated continuity of the mass into intraperitoneal fat, a conclusive diagnosis of diaphragmatic hernia could not be made at that time. On April 30, 1998, a thoracotomy was performed on the basis of a preoperative diagnosis of mediastinal lipoma. During surgery, a hernial ring was observed slightly to the right and behind the sternum. The hernia consisted only of greater omentum, and was diagnosed as Morgagni's foramen hernia.

Diagnosis, Differential↗
PubMed1999

[Sarcoidosis synchronously detected in identical twins].

We report on the synchronous detection of sarcoidosis in identical 22-year-old male twins. The patients visited a nearby physician because of fever and cough, were found to have abnormal chest shadows and thus admitted to our hospital. Both had swollen cervical and hilar nodes and lesions in both left and right lung fields, and also presented similar clinical symptoms. However, bilateral uveitis was observed only in the elder twin. Because epithelioid cell granulomas without caseous necrosis were histopathologically observed in tissue specimens from their cervical lymph nodes, the patients were given a diagnosis of sarcoidosis. Although they were positive for the HLA-D antigens DR 2 and DR 12, they were negative for DRw 52. an antigen that is considered to be quite common in Japanese sarcoidosis patients. Genetic factors were thought to be involved in the onset of sarcoidosis in these twins.

Adult↗
PubMed1999

[Three cases of semi-invasive pulmonary aspergillosis occurring in healthy or diabetic individuals].

We encountered three cases of suspected semi-invasive pulmonary aspergillosis, occurring in healthy or diabetic patients. Radiographic findings disclosed cavity formation in 2 of the patients, but only nodular lesions in 1. The beta-D glucan level was elevated in 1 patient, but was within the normal range in the other 2. Morphological findings indicated that all 3 patients had pulmonary aspergillosis. Following the oral administration of FLCZ to 1 patient and ITCZ to the other 2 for about 2 months, the radiographic lesions resolved and hematologic inflammatory reactions cleared up. Gefter et al and Sider et al have defined 2 types of aspergillosis that occur in mildly immuno-compromised or healthy individuals: the semi-invasive type, which destroys pulmonary tissue without vascular invasion and leads to cavity formation; and the locally invasive type, which is characterized by nodular or massive radiographic lesions without cavity formation. Semi-invasive aspergillosis was diagnosed in all 3 of the cases we reported.

Adult↗
PubMed1998

Acinic Cell Adenocarcinoma Arising in the Breast of a Young Male: A Clinicopathological, Immunohistochemical and Ultrastructural Study.

A 23-year-old man with acinic cell adenocarcinoma of the breast is reported. He presented with a 4.8 x 4.2 cm mass in his left breast, and excisional biopsy was performed. Under the light microscope, tumor cells had abundant periodic acid-Schiff-positive secretory granules and eosinophlic cytoplasms. Electron microscopy revealed the granules to have various electron densities, a finding characteristic of acinic cell adenocarcinoma. Immunohistochemically, the tumor cells were stained with salivary-type amylase. Electron microscpic and immunohistochemical investigation greatly facilitated the diagnosis of this acinic cell adenocarcinoma, which was in an unusual location. We believe this is the first case report of acinic cell adenocarcinoma of the mammary gland studied utilizing light microscopic, ultrastructural and immunohistochemical techniques.

Journal Article↗
PubMed1998

Overproduction of vascular endothelial growth factor/vascular permeability factor is causative in Crow-Fukase (POEMS) syndrome.

Crow-Fukase or POEMS syndrome of polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes is a rare multisystem disorder of obscure pathogenesis that is associated with microangiopathy, neovascularization, and accelerated vasopermeability. We examined the levels of the vascular endothelial growth factor/vascular permeability factor (VEGF) in the serum and cerebrospinal fluid (CSF) from 10 patients with this syndrome. Serum VEGF levels were about 15-30 times those in control subjects or patients with Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), and other neurological disorders. The CSF VEGF levels, however, were similar to those found in GBS and CIDP. Elevated VEGF levels in the serum decreased in 7 patients with Crow-Fukase syndrome after conventional therapy. The principal isoform of VEGF in Crow-Fukase syndrome was VEGF165. Elevated VEGF was independent of M-protein. Our results suggest that the overproduction of VEGF is important in the pathogenesis of this disorder.

Adult↗
PubMed1998

End-to-side neurorraphy: a long-term study of neural regeneration in a rat model.

This study evaluated long-term reinnervation of an end-to-side neurorraphy and the resultant functional recovery in a rat model. The divided distal posterior tibial nerve was repaired to the side of an intact peroneal nerve. Control groups included a cut-and-repair of the posterior tibial nerve and an end-to-end repair of the peroneal nerve to the posterior tibial nerve. Evaluations included walking-track analysis, nerve conduction studies, muscle mass measurements, retrograde nerve tracing, and histologic evaluation. Walking tracks indicated poor recovery of posterior tibial nerve function in the experimental group. No significant difference in nerve conduction velocities was seen between the experimental and control groups. Gastrocnemius muscle mass measurements revealed no functional recovery in the experimental group. Similarly, retrograde nerve tracing revealed minimal motor neuron staining in the experimental group. However, some sensory staining was seen within the dorsal root ganglia of the end-to-side group. Histologic study revealed minimal myelinated axonal regeneration in the experimental group as compared with findings in the other groups. These results suggest that predominantly sensory regeneration occurs in an end-to-side neurorraphy at an end point of 6 months.

Action Potentials↗
PubMed1998

Long-term observation of the effect of peripheral nerve injury in neonatal and young rats.

The purpose of this study was to observe functional recovery and motoneuron death after nerve transection-and-repair in neonatal versus young animals. One hundred nine Lewis rats underwent posterior tibial nerve transection-and-repair at 6 or 22 days of age. Fifty-two and fifty-seven nerves at the 6- and 22-day times were used for endpoint analysis at 1, 3, 10, and 14 months. These assessments included serial functional walking track analysis, electrophysiologic studies, muscle mass evaluation, motoneuron counts with retrograde horseradish peroxidase tracing, and histologic and morphometric nerve analysis. Walking track analysis and nerve conduction velocity indicated significantly poorer functional regeneration in the 6-day-old group than in the 22-day-old group. Muscle mass in the 6-day-old group did not recover as well as in the 22-day-old group. Motoneuron numbers stained with horseradish peroxidase were less in the 6-day-old group than in the 22-day-old group. In contrast, morphometric analysis did not reach significance. This study suggests that the same nerve injury sustained in a neonatal rat is less likely to demonstrate functional recovery than one sustained in a young rat.

Animals↗
PubMed1998

Surgical successful treatment of Cushing's syndrome in a pregnant patient complicated with severe cardiac involvement.

We encountered a case of a pregnant woman with adrenal causes of Cushing's syndrome who exhibited congestive heart failure as an initial symptom. Since the patient was also a diabetic, we treated her with high levels of diuretics and insulin. Echocardiography revealed a remarkable thickening of the left ventricle without asymmetric hypertrophy. The diagnosis of Cushing's syndrome caused by adrenal adenoma was confirmed by the endocrinological data and magnetic resonance imaging. The right adrenal adenoma was removed in the 28th week of pregnancy. After the operation, her congestive heart failure and hyperglycemia dramatically improved. Five weeks after the operation, she delivered a normal infant by caesarean section without complications. Only 4 months after delivery, the thickening of her left ventricle was normalized. We consider that the progression of her left ventricular hypertrophy induced by the changes in hemodynamic load during pregnancy may have been augmented by the excess of plasma cortisol. Operative therapy may be recommended for pregnant Cushing's syndrome patients with severe hypercortisolism complicating congestive heart failure.

Adenoma↗
PubMed1998

Pregnant woman with transient diabetes insipidus resistant to 1-desamino-8-D-arginine vasopressin.

We encountered a pregnant woman with transient diabetes insipidus which developed during the third trimester. A hypertonic saline infusion study did not concentrate the osmolality of urine. Her laboratory data showed hypokalemia, hyperreninemia, an increased concentration of plasma aldosterone and an increased urinary excretion rate of prostaglandin E2, which resembled hyperprostaglandin E-syndrome. T1-weighted magnetic resonance imaging of the posterior pituitary gland revealed decreased intensity. Polyuria reached 4-6 L daily, and urine osmolality remained dilute despite a lapse of four days since treatment with intranasal 1-desamino-8-D-arginine vasopressin (dDAVP: 10-25 microg every 12 h). The patient was conservatively managed without medical treatment, then delivered in the 38th week of pregnancy without complication. The osmolality of the patient's urine was higher than that of the plasma when tested 3 days postpartum. The abnormality of magnetic resonance imaging of the posterior pituitary gland disappeared at 6 months after delivery. We consider that subclinical nephrogenic diabetes insipidus in our patient was exacerbated during pregnancy.

Adult↗
PubMed1998

Mechanism of increased serum cytokeratin 19 fragment levels in patients with diabetic nephropathy as a model of chronic renal failure.

We examined serum and urinary cytokeratin 19 fragment (CYFRA 21-1) levels in patients with diabetic nephropathy as a model of chronic renal failure, to investigate the mechanism of increased serum CYFRA 21-1 levels in chronic renal failure. Serum and urinary CYFRA 21-1 levels in non-insulin-dependent diabetes mellitus (NIDDM) patients with abnormal urinary immunoglobulin G (IgG) levels (>1.1 mg/g x Cr, n=126) were higher than those with normal urinary IgG levels. In NIDDM patients with normal urinary IgG levels (n=81); the urinary albumin or transferrin levels were not related to serum or urinary CYFRA 21-1 levels. We speculate that the increased serum CYFRA 21-1 levels contribute to metabolic abnormality in the kidney itself rather than the decreased urinary excretion per se, and that increased urinary CYFRA 21-1 levels are found in advanced cases of diabetic nephropathy with destruction of the size barrier.

Albuminuria↗
PubMed1997

Antibodies to potassium channels of PC12 in serum of Isaacs' syndrome: Western blot and immunohistochemical studies.

We investigated the pathophysiology of nerve hyperexcitability in a patient with Isaacs' syndrome, who had typical clinical and electromyographic features and responded to plasma exchange. Immunoblotting and immunohistochemistry studies showed that antibodies from this patient reacted with the lysate of a neuronal cell line (PC12). In Western blots, constituents of the patient's serum, particularly immunoglobulin M, reacted with proteins of approximately 50 and 18 kDa, whereas the control serum did not. A cross-linking study with alpha-dendrotoxin (7 kDa) showed a 57 kDa protein-peptide complex. Immunohistochemistry showed that the patient's serum reacted with PC12 cells and human intramuscular nerve axons. Our findings indicate that in Isaac's syndrome nerve hyperexcitability is the result of the immunological involvement of the voltage-dependent potassium channels located along the distal motor nerve or at the nerve terminal.

Aged↗