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Biomedical subjects

M Matsuo

Publications and source records attributed to M Matsuo.

644 records · Page 36Linked to original sources
PubMedDate not supplied

Distinction of hepatic vein from portal vein by MR imaging.

Fast magnetic resonance (MR) imaging techniques are assuming importance in imaging of the abdomen in part due to their ability to produce images during breath-holding, which ensures high spatial resolution and no respiratory motion artifacts. One problem with rapid scanning of the liver, shared with other MR techniques, is confusion between portal and hepatic veins due to similarity in signal intensity. The fast low angle shot (FLASH) technique (flip angle 40 degrees, repetition time 28 ms, and echo time 16 ms) produces high signal in both venous systems. To remedy the problem we incorporated presaturation pulses applied across the portal and mesenteric veins to the FLASH technique; this induced a decrease in signal in the portal venous system and facilitated their differentiation from hepatic veins. Moreover, in one patient an intraportal tumor thrombus not detected on the standard FLASH technique was rendered visible by presaturation. Although the presaturation pulses in the present series were confined to the sagittal plane, the technique should be applicable in any plane as dictated by the anatomy and direction of blood flow. We anticipate wide use of combined presaturation and rapid scanning techniques.

Hepatic Veins↗
PubMedDate not supplied

Recurrent parotid swelling in children: clinical features useful for differential diagnosis of Sjögren's syndrome.

Immunological evaluations were performed in 59 children with at least five episodes of parotid swelling. Autoantibody(ies) was transiently or persistently detected in 12 (20%) of 59 patients with recurrent parotitis. Three of the 12 children with autoantibodies were diagnosed as having Sjögren's syndrome. The mean age at onset of parotid swelling in Sjögren's syndrome was significantly higher than that of recurrent parotitis of unknown etiology. The present study and the review of the literature suggest that patients with the onset of parotid swelling at age five years or over deserve screening for underlying systemic immune disorders.

Adolescent↗
PubMedDate not supplied

Characteristics of heparin-induced platelet aggregates in chronic hemodialysis with long-term heparin use.

This study investigated the usefulness of a new platelet aggregometer with a laser-scattering method for detection of heparin-induced small platelet aggregates in chronic hemodialysis patients. Using this device, small platelet aggregates (particle size 9--25 microm) were detectable, but these aggregates could not be detected using a conventional light transmittance aggregometer. The laser-scattering intensity of the small aggregates was increased with an increasing dosage of heparin as agonist. These aggregates were disaggregated by heparin neutralization with protamine sulfate. Induction of small platelet aggregates by heparin was inhibited by preincubation with nafamostat mesilate, a synthetic protease inhibitor, and cilostazol, a platelet phosphodiesterase inhibitor, but not by the therapeutic doses of aspirin or argatroban, a selective thrombin inhibitor. The dialysis patients with long-term heparin use could be divided into two groups: responders to heparin, who formed small aggregates with a scattering intensity over 0.51 x 10(5) V after addition of 0.5 IU/ml of heparin obtained from normal platelet-rich plasma without inductor, and nonresponders, who showed an intensity under 0.51 x 10(5) V. The rate of heparin responders among dialysis patients was significantly higher than the rate among normal subjects. Heparin-induced small aggregates were detected in 13 (36.1%) of 36 normal subjects with no history of heparin infusion and in 37 (62.7%) of 59 dialysis patients who received heparin anticoagulation during each dialysis session. Dialysis patients with coronary heart disease did not have a significantly higher rate of heparin responders than patients without complications. There was no significant difference in the positivity rate between cases complicated by diabetes and those without diabetes. In patients who had more than 2 episodes of thrombotic occlusions of an arteriovenous fistula, the rate of responders and the enhancement of scattering intensity of small aggregates by heparin were significantly increased compared with these in patients without occlusions during the preceding 2 years. Moreover, dialysis patients with a positive heparin response showed a marked increase in scattering intensity of small aggregates after heparin infusion in each dialysis session. Determination of the response to heparin prior to heparin use in dialysis patients with repeated thromboembolic complication may be useful in choosing anticoagulant regimens.

Aged↗
PubMedDate not supplied

Anticoagulation with nafamostat mesilate, a synthetic protease inhibitor, in hemodialysis patients with a bleeding risk.

Nafamostat mesilate (FUT) is a synthetic serine protease inhibitor with a short half-life that is used during hemodialysis (HD) in patients with a high risk of bleeding because it does not prolong the systemic coagulation time. To evaluate whether or not FUT is able to effectively prevent clot formation in the extracorporeal circuit without increasing systemic bleeding, HD using FUT was carried out for 33 sessions in 12 patients with a high risk of bleeding. FUT was continuously infused during HD at 20-40 mg/h to maintain a 2-fold prolongation of activated partial thromboplastin time (APTT) at the dialyzer outlet on the venous side of the circuit. No APTT prolongation was observed on the arterial side of the circuit before FUT infusion, and none of the patients showed increased bleeding during or after HD. However, clots formed in the arterial chamber (30.3%), the dialyzer (36.6%), and the venous chamber (15.1%). In 2 of the 12 patients, HD was discontinued due to clot formation despite sufficient prolongation of APTT. The mean levels of the thrombin-antithrombin III complex and prothrombin activation fragment 1 + 2 in the circuit gradually increased on both the arterial and venous sides during HD using FUT, and protein C activity decreased. No significant changes in these parameters occurred during heparin HD in the same patients after the bleeding episode had resolved. Despite sufficient prolongation of APTT in the circuit, FUT was less effective in suppressing thrombin generation when compared to heparin.(ABSTRACT TRUNCATED AT 250 WORDS)

Anticoagulants↗
PubMedDate not supplied

Extrinsic coagulation factors and tissue factor pathway inhibitor in end-stage chronic renal failure.

The relationship between extrinsic coagulation factors, tissue factor pathway inhibitor (TFPI) and activated factor XII (FXIIa) was examined in 71 patients with end-stage chronic renal failure. They had chronic stable uremia due to regular hemodialysis. The patients were divided into two age- and sex-matched groups with and without diabetes mellitus. As extrinsic coagulation parameters, FVIIa and FVII antigen (FVIIag), tissue factor antigen and TFPI (the activity and antigen) were measured. FXIIa was measured as a marker of contact activation, and thrombin generation was evaluated using the two markers thrombin-antithrombin III complex and prothrombin fragment 1 + 2. In both hemodialysis groups with and without diabetes, significant elevations of FXIIa, FVIIa and tissue factor, with high levels of TFPI, were found. Thus, hyperactivation of the coagulation system was in part compensated by TFPI, and a significant increase in FXIIa could not directly affect FVIIa hyperactivation. No differences of these parameters, except for FVIIag and fragment 1 + 2, were found between the groups with and without diabetes. It is suggested that the long-term hemodialysis might have masked any differences due to the underlying disease in these two subgroups.

Aged↗
PubMedDate not supplied

Induction of bone loss by bile duct ligation in rats.

Metabolic bone loss is the most common complication of chronic liver disease. However, there is little information available about bone loss in rats with a ligated bile duct, a biliary-type of experimental cirrhosis model. Therefore, in this study, the effect of bile duct ligation (BDL) on bone mineral density (BMD) and plasma insulin-like growth factor-I (IGF-I) levels was examined in rats. Two weeks after BDL operation, the rats with a ligated bile duct showed a pronounced and significant decrease in both trabecular and cortical BMD of the femur. In these rats, decreases in food intake and plasma IGF-I levels plus elevated levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and bilirubin were also observed. When the effect of dietary restriction (30% or 50%) over 2 weeks was then investigated in normal rats, 50% food restriction resulted in a significant decrease in femoral trabecular bone density although BMD was unchanged by 30% dietary restriction. The plasma levels of IGF-I were also decreased in food-restricted rats. Thus, the decrease in femoral bone density in 50% food-restricted rats was less potent compared with BDL rats; nevertheless, the decrease in plasma levels of IGF-I was almost equally potent in both BDL and food-restricted rats. Overall, this study showed that BDL operation resulted in a pronounced bone loss in rats, but also that this bone loss might not be merely due to the decreases in food intake and plasma IGF-I levels. These results suggest that BDL in rats is a useful experimental cirrhosis model for evaluating the bone loss associated with chronic liver disease.

Animals↗
PubMedDate not supplied

Ossification of the posterior longitudinal ligament: MR evaluation.

PURPOSE: To investigate the MR appearance of ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. MATERIALS AND METHODS: A retrospective review of MR images and conventional tomograms in 147 patients. RESULTS: In the sagittal plane, proton-density images identified the ossified lesions more clearly than did T1- and T2-weighted images. All axial sequences identified the lesions much frequently. T1-weighted images often showed areas of increased intensity within the lesions of the continuous and mixed type, especially within the thick lesions. Fat images by Dixon technique demonstrated same areas of increased intensity, which strongly suggested fatty marrow formation. On conventional tomograms, configurations of radiolucent areas within the lesions corresponded to areas of increased intensity on T1-weighted images. CONCLUSION: Proton-density sagittal and axial images are important in establishing the diagnosis of OPLL. The areas of increased intensity on T1-weighted images and radiolucent areas suggest marrow formation.

Adult↗
PubMedDate not supplied

Familial hypocalciuric hypercalcemia involving four members of a kindred including a girl with severe neonatal primary hyperparathyroidism.

A family with hypercalcemia in four members is reported. The proband, a newborn girl presenting with inadequate sucking due to muscle hypotonia, marked thoracic deformity due to decalcification, hypercalcemia, and hypophosphatemia, suffers from cerebral damage due to hypoxia despite successful total parathyroidectomy of four hyperplastic glands and replacement therapy. Her 31-year-old father showed CCa/Ccr of 0.0094, normal serum Mg, hypercalcemia, hypophosphatemia and normal renal concentrating ability without kidney stone and bone abnormality. Subtotal parathyroidectomy caused only a transient fall of serum Ca. His half sister and her daughter also had symptomless hypercalcemia. Recognition of familial hypocalciuric hypercalcemia is important to avoid unnecessary parathyroid surgery and to respond effectively to severe neonatal primary hyperparathyroidism occasionally seen in such kindred.

Adult↗
PubMedDate not supplied

Aggressive appearance of non-ossifying fibroma with pathologic fracture: a case report.

An 11-year-old boy presented with a lytic lesion in the proximal humeral metaphysis. In spite of an aggressively reactive appearance on plain radiography and MR imaging, this lesion proved to be a non-ossifying fibroma. Fracture of the cortical shell probably contributed to the relatively wide zone of transition and periosteal reaction on plain radiography and the reactive change on MR imaging.

Bone Neoplasms↗
PubMedDate not supplied

Case report: MR findings of a retained surgical sponge.

We describe here a case in which a retained surgical sponge progressed into the perirenal space and posterior pararenal space from the pelvic cavity. Sonography, CT, and T1-weighted MR image analyses could not show clearly the characteristic structure of the surgical sponge, but T2-weighted MR imaging showed a folded fabric appearance within the cystic mass. Surgical findings confirmed a lobulated cystic mass containing yellowish fluid and a surgical sponge.

Aged↗
PubMedDate not supplied

Case report: MR findings of Guillain-Barré syndrome.

Guillain-Barré syndrome (GBS) is characterized as an acute, symmetrically progressive, inflammatory demyelinating polyneuropathy. We report a case of GBS in which gadolinium-enhanced magnetic resonance (MR) imaging showed marked enhancement of nerve roots of the conus medullaris and cauda equina. On enhanced MR imaging, the spinal cord and nerve roots in the thecal sac generally do not take up much gadolinium because of the blood-nerve barrier or blood-brain barrier. Therefore, in our case, marked enhancement of nerve roots indicates a breakdown of the blood-nerve barrier. It is thought to correlate with the inflammatory infiltration of GBS.

Cauda Equina↗
PubMedDate not supplied

An adult case of retropharyngeal cellulitis; diagnosis by magnetic resonance imaging.

We experienced an adult case of cellulitis in the prevertebral space with retropharyngeal and danger space, and, which was suspected to be due to a fish bone stuck in the throat. Its lesion could not be demonstrated on plain radiograph, postcontrast computed tomography, or laryngoscopy, but noncontrast magnetic resonance imaging demonstrated the lesion and was useful in assessing the efficacy of medication.

Aged↗
PubMedDate not supplied

Ectopic ureter draining into seminal vesicle cyst: usefulness of MRI.

Ectopic ureter draining into seminal vesicle cyst is very rare congenital anomaly, which is thought to be caused by ectopic ureteral bud arising on the mesonephric duct. It is often associated with ipsilateral renal agenesis. We experienced a case of ectopic ureter draining into seminal vesicle cyst that is associated with ipsilateral renal agenesis. Generally, an invasive modality, that is, cyst puncture, cystography, or seminal vesiculography, is essential in the confirmative diagnosis of ectopic ureter. However, we could establish a definitive diagnosis with magnetic resonance imaging.

Adult↗