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Biomedical subjects

T Shirota

Publications and source records attributed to T Shirota.

At least 73 records · Page 4Linked to original sources
PubMed1992

Hyperbilirubinemia after esophagectomy. A possible role of lipid peroxidation.

Postoperative hyperbilirubinemia was investigated in 18 patients who underwent a single-staged esophagectomy and reconstruction. The total serum bilirubin (TSB) concentration increased progressively after surgery without any evidence of sepsis and reached a peak on day 5 from 0.5 +/- 0.1 to 2.4 +/- 0.4 mg/dl (p less than 0.01), and then decreased by day 14. The TSB concentration rose above 2.5 mg/dl on days 5 or 7 in 8 patients (44%). Alkaline phosphatase and SGOT showed a mild increase during the postoperative period. The increase in the serum lipid peroxide (LPO) concentration, which was measured as malondialdehyde, after surgery correlated closely with the change in the TSB concentration. The LPO concentration was significantly elevated only in the patients with postoperative hyperbilirubinemia, and showed a correlation with the TSB concentration (r = 0.81, p less than 0.01). The level of serum alpha-tocopherol decreased after surgery, but did not differ between the patients with or without postoperative hyperbilirubinemia. These results suggest that lipid peroxidation reactions play a role in the development of hyperbilirubinemia after esophagectomy, which may be due to benign intrahepatic cholestasis.

Aged↗
PubMed1992

Alterations of bone marrow sinus endothelium induced by ionizing irradiation: implications in the homing of intravenously transplanted marrow cells.

The endothelium of bone marrow sinuses is a continuous layer which is selective in its cellular transport. It is not known how selective and massive seeding of hemopoietic progenitor cells after intravenous transplantation of marrow cells occurs. We postulate that the conditioning irradiation could disrupt the endothelial barrier, thus permitting the "homing" of progenitor cells to occur. To demonstrate this phenomenon, we irradiated mice with doses ranging from 100-2000 cGy-total body and studied perfusion-fixed marrow by transmission electron microscopy. The major finding was sloughing and denudation of plasma membrane, particularly on the luminal side of endothelium. Membrane vesiculation was also frequently seen in this border. Moreover, dilatation of the perinuclear space and rough endoplasmic reticulum was commonplace and testified to instability and fragility of the membrane system. Focal cytoplasmic swelling of endothelium was seen reflecting increased permissiveness of the endothelial barrier. Endocytosis and phagocytosis were increased in the marrow; and the endothelium, normally quiescent with regard to phagocytosis, was now overtly phagocytic. A dipogenecity of the adventitial layer was increased as hemopoietic function of marrow decreased. The end result of membrane alterations in the endothelium was the appearance of discontinuities in these cells, which form the essential element of bone marrow-blood barrier. Consequent to these discontinuities, the permissiveness of the endothelial barrier was enhanced and those cellular elements, such as mature, nonreticulated erythrocytes that are normally confined to the vascular space, now appeared in large number in the hemopoietic compartment. With low doses, these findings were transient and repair set in by 1-2 weeks. With higher doses, total disruption of marrow-blood barrier occurred and the process did not seem to be repairable. We conclude that the conditioning irradiation before bone marrow transplantation is essential in disrupting the endothelial barrier and permitting large-scale entry of transplanted cells into the hemopoietic compartment.

Animals↗
PubMed1992

Primary hypothyroidism and multiple endocrine failure in association with hemochromatosis in a long-term hemodialysis patient.

A 56-year-old male patient on chronic hemodialysis developed liver cirrhosis. He received a total of 20 liters of blood transfusion. Bronze pigmentation of the skin and iron deposition to the liver, spleen, pancreas and thyroid gland, which was demonstrated by computed tomography and magnetic resonance imaging studies, and histological demonstration of iron deposition to the thyroid gland, bone marrow and gastric mucosa established a diagnosis of secondary hemochromatosis. Endocrine work-up revealed the presence of diabetes mellitus with minimum insulin secretory response, primary (or thyroprivic) hypothyroidism, hypoparathyroidism and hypogonadotropic hypogonadism. A wide-spread endocrine involvement as seen in this patient is a rare clinical feature of hemochromatosis secondary to massive blood transfusion in hemodialysis patients. Particularly, primary hypothyroidism due to iron deposition to the thyroid gland was quite a rare feature of hemochromatosis.

Diabetes Mellitus↗
PubMed1991

[Studies on the renal handling of urea nitrogen, creatinine, water and electrolytes in hyperthyroid patients with Graves' disease].

To delineate the pathophysiological basis for increased blood urea nitrogen (BUN), decreased serum creatinine (SCr) and increased BUN/SCr ratio in patients with hyperthyroidism due to Graves' disease, systematic evaluation on renal handling of solutes and water was carried out before and during treatment of the disease. First, BUN, SCr, serum sodium (Na), serum potassium (K), serum chloride (Cl), creatine kinase (CK), serum triiodothyronine (T3) and serum thyroxine (T4) were consecutively measured in 16 patients (aged 18-62 yrs, 4 males and 12 females) with Graves' disease before and during antithyroid drug therapy, and 16 healthy subjects (aged 22-64 yrs, 4 males and 12 females) served as controls. BUN (14.8 +/- 2.9 mg/100ml) was significantly higher (p less than 0.01), and SCr (0.62 +/- 0.16 mg/100ml) and CK (41.7 +/- 23.6 U/l) were significantly lower (p less than 0.01) in untreated patients compared to respective values in the control group (BUN, 13.2 +/- 2.9 mg/100ml; SCr, 0.87 +/- 0.16 mg/100ml; CK, 99.3 +/- 49.5 U/l). Consequently, BUN/SCr ratio was significantly elevated (p less than 0.01) in the patients. As T4 and T3 returned to normal, BUN, SCr, BUN/SCr ratio and CK of the patients also normalized. Serum electrolytes were not significantly different in the patients compared to the controls. Second, renal clearance of para-aminohippurate (CPAH), inulin (CIn), creatinine (CCr), free water (CH2O) and chloride (CCl) was evaluated in 7 untreated patients (aged 17-44 yrs, 4 males and 3 females) and in 7 controls (aged 24-39 yrs, 5 males and 2 females). In patients with untreated Graves' disease, CPAH, CCr and Curea were significantly greater than in the controls (847 +/- 367 vs 442 +/- 124 ml/min, p less than 0.05, 132.7 +/- 14.7 vs 76.6 +/- 14.4 ml/min, p less than 0.01, and 86.9 +/- 16.0 ml/min vs 52.1 +/- 12.6 ml/min, p less than 0.05, respectively). CIn was slightly but insignificantly increased in the patients (95.3 +/- 20.8 ml/min) compared to the controls (76.7 +/- 13.3 ml/min). As a result, CCr/CIn and Curea/CIn were significantly greater in the patients than in the controls (142.7 +/- 32.0 vs 100.7 +/- 7.1%, p less than 0.01, 92.4 +/- 18.7 vs 68.4 +/- 14.4%, p less than 0.05, respectively). The difference between CCr and CIn indicates that 40% of urinary creatinine is of tubular origin. Renal excretion of urea and creatinine was increased by 117% and decreased by 77%, respectively in the patients, but the differences were not statistically significant.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1991

Histologic findings of apatite-titanium complex dental implants in the jaws of dogs.

This study concerns the histologic examination of apatite-titanium complex dental implants (two-piece, cylindrical type) in dogs. There was no plaque control. One to 3 months after implantation, the surface of the apatite root was directly bound to newly formed, woven bone. Seven-and-a-half months to 1 year after implantation, the apatite root was directly bound to the newly formed lamellar bone, which provided strong bone bonding (apatite-bone bonding). There appear to be two types of mechanisms for the resorption of apatite ceramics: first, cellular-type resorption by both multinuclear and mononuclear macrophages; and second, a noncellular, fluid mechanism (dissolution). The gingival sulcus around implants and downward growth of the epithelial cells could be observed in almost all of the implants. There was no cellular inflammation in the tissue around the implants, in the nasal cavity, or in the maxillary sinus. From this study we concluded that clinical application of this dental implant system would be practical.

Animals↗
PubMed1991

An experimental study of healing around hydroxylapatite implants installed with autogenous iliac bone grafts for jaw reconstruction.

The purpose of this study was to evaluate the use of hydroxylapatite implants (HA) with autogenous bone grafts for jaw reconstruction. After autogenous iliac bone grafts were transplanted to 36 rabbit mandibles, an HA implant was installed into the graft immediately (IM group), or 90 days (90D group), or 180 days (180D group) later. The animals were killed 7, 14, 30, 60, 90, and 180 days after the HA implant placement. The healing process was examined histologically, and histomorphometric measurements were made with a computer-based image analyzer to quantify the percentage of HA-bone bonding and trabecular bone in the medullary cavity. In the IM group, the HA-bone bonding tended to be deterred by fibrous tissue, and the rate of HA-bone bonding (BBSR) was less than that of the other groups. The trabecular bone around the implants tended to decrease after 30 days in all groups. However, the average of the trabecular bone specific volume (tVsp) in the 90D group was about 10% higher than that in the other groups. From these results, it is concluded that in clinical use of HA-coated dental implants with autogenous bone grafts, the time of installation should not be immediately after the bone graft, but when there is sufficient newly formed trabecular bone to enhance HA-bone bonding.

Animals↗
PubMed1991

Improvement in iron deficiency anemia through therapy with ferric ammonium citrate and vitamin C and the effects of aerobic exercise.

In 781 female college students, there were 41 cases of iron deficiency anemia, 209 of latent iron deficiency, 3 of other anemias, and 528 normal cases. Fifty-four volunteers recruited from the iron deficiency anemia and severe latent iron deficiency groups were randomly divided into 4 study groups. Groups I and III received 500 mg of vitamin C daily, and groups II and IV received ferric ammonium citrate (FeAC; equivalent to 6 mg iron) in addition to vitamin C for 9 weeks. Groups I and II were loaded by aerobic exercise at 50% VO2 max. Significant differences between groups were noted in serum ferritin (SF) in III/IV, hematocrit (Ht) in II/III and III/IV, and reticulocytes (RET) in I/II, I/IV, and III/IV. Hemoglobin (Hb) and other iron-related blood indices tended to normalize in groups II and IV when compared with the pre-values. VO2 max was elevated in groups I and II regardless of iron treatment, but was augmented more in group II than group I.

Adolescent↗
PubMed1991

Cyclophosphamide-induced alterations of bone marrow endothelium: implications in homing of marrow cells after transplantation.

Bone marrow transplantation requires infusion of stem cells i.v. and transport of these cells to the extravascular compartment of the marrow where hemopoiesis takes place. This requires massive cellular traffic across the sinus endothelial barrier. We tested the hypothesis that the conditioning regimen given before transplantation alters the endothelium and permits the traffic of transplanted cells into the hemopoietic compartment. C57B1 mice were given cyclophosphamide i.p. in doses comparable to those used in conditioning regimens. Marrow was perfusion-fixed and studied by electron microscopy at various time after the dose. The salient feature of cyclophosphamide-induced endothelial injury was membrane instability, manifested by sloughing and vesiculation of membrane on the luminal surface. Considerable loss of membrane was associated with a reduction in the surface area of endothelium. There was also an associated loss of integrity of sinus endothelium so that mature circulating red cells, normally confined to the vascular space, could now traverse the vascular wall and appear in the hemopoietic compartment. Moreover, perisinal macrophages, normally confined to extravascular space, were now seen in the lumen. We conclude that the cytotoxic conditioning regimen, given with different objectives, may facilitate the traffic of transplanted cells into the hemopoietic compartment of the marrow.

Animals↗
PubMed1990

Usefulness of thrombelastography for dosage monitoring of low molecular weight heparin and unfractionated heparin during hemodialysis.

Low molecular weight heparin (LMH) acts as an anticoagulation agent mainly through its anti-activated coagulation factor X (Xa) activity. Thrombelastography (TEG) is expected to be useful to monitor the dosage of LMH during hemodialysis because reaction time on TEG (TEG-r) is considered to reflect blood thromboplastin formation time, which depends on the formation of Xa. To test this possibility, we compared the usefulness of TEG, activated coagulation time (ACT), activated partial thromboplastin time (APTT), and anti-Xa activity in 28 hemodialysis patients using both conventional unfractionated heparin (UFH) and LMH on separate dialysis procedures. Anti-Xa activity of LMH was comparable to that of UFH when it was measured using both LMH and UFH as standards. Anti-Xa activity, which theoretically depended on the heparin concentration in blood samples, did not correlate with the degree of dialyzer clotting. The APTT correlated well with anti-Xa activity in patients using LMH (r = 0.686, p less than 0.01) and UFH (r = 0.906, p less than 0.01), but not with the degree of dialyzer clotting. The TEG-r correlated well with the degree of dialyzer clotting both in patients using LMH and those using UFH (measurements of samples obtained from the venous side of the extracorporeal circuit) and weakly correlated with anti-Xa activity in patients using LMH (r = 0.402, p less than 0.05). The ACT did not correlate with the degree of dialyzer clotting or anti-Xa activity. These results suggest that TEG-r reflects the efficacy of heparin in the extra-corporeal blood circuit, whereas APTT mainly reflects heparin concentration of the blood samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Factor Xa Inhibitors↗
PubMed1990

Elevated plasma atrial natriuretic peptide level in the early phase of microalbuminuria in patients with non-insulin-dependent diabetes mellitus.

Plasma atrial natriuretic peptide (ANP) levels were examined in 66 patients with non-insulin-dependent diabetes mellitus (NIDDM), and in 9 age-matched normal controls and 18 hypertensive controls. The diabetic patients were classified into three groups according to random urine albumin/creatinine ratio (ACR, mg/g or mg/88.4 nM); group 1 (normo-albuminuria, ACR less than 20, n = 34), group 2 (borderline microcalbuminuria, 20 less than or equal to ACR less than 100, n = 17) and group 3 (manifest microalbuminuria and macroalbuminuria, 100 less than or equal to ACR less than 2000, n = 15). Plasma ANP levels (pg per ml) were significantly elevated in group 2 (46.0 +/- 19.0 SD) when compared with either normal controls (23.8 +/- 14.2), group 1 (28.9 +/- 15.6) or group 3 (26.0 +/- 12.9). This increase in plasma ANP levels was not related to hypertension. Furthermore, plasma ANP levels correlated positively with log(ACR) among the patients with ACR under 100 (groups 1 and 2 combined, r = 0.4701, p less than 0.01). These results suggest that an elevated plasma ANP level in the early phase of microalbuminuria possibly plays a pathophysiological role in the development of nephropathy in NIDDM patients.

Albuminuria↗
PubMed1989

Immunohistochemical localization of Na+, K+-ATPase in human normal and malignant pancreatic tissues.

Localization of Na+, K+-ATPase in the human pancreas was investigated immunohistochemically using rabbit antisera against Na+, K+-ATPase of the human kidney. The reaction product existed only on the luminal surfaces of both centroacinar and ductal cells in normal pancreatic tissue, whereas in chronic pancreatitis the localization of Na+, K+-ATPase was found frequently on the luminal surfaces of both centroacinar and ductal cells, and on the basolateral surfaces of some ductal cells. However, in acinar cells, the distribution of Na+,K+-ATPase was not detected in either the normal pancreas or chronic pancreatitis. In pancreatic carcinoma tissues, Na+,K+-ATPase existed very rarely in malignant cells. These results indicate that Na+,K+-ATPase is immunohistochemically localized on the membranes of centroacinar and ductal cells of the human pancreas, and that the antigenicity of Na+,K+-ATPase in pancreatic carcinoma cells differs from that in normal cells.

Chronic Disease↗
PubMed1989

[Specific cytoplasmic crystalline inclusions in multiple myeloma with amyloidosis].

It is widely known that multiple myeloma is sometimes followed by amyloidosis. It is also not particularly rare that inclusions exist in myeloma cells. However, there has been no previous report of a case of myeloma with both inclusions and amyloidosis. A 60-year-old female initially complained of a tendency to bleed, which was caused by fibrinolysis. Amyloid deposition in bone marrow stroma and the gastric submucosa was recognized, in addition to crystalline inclusion in the cytoplasm of myeloma cells. An immunoelectron microscopic study demonstrated the amyloid fibrils and the crystals to react positively to anti-lambda serum. No crystals were found in macrophages, and no relationship was recognized between lysosomes and crystalline inclusions in the cytoplasm of myeloma cells. This case had disturbed transportation or secretion of the lambda type L chain and it was considered that crystals derived from the lambda type L chain were formed in the cytoplasm of myeloma cells.

Amyloidosis↗
PubMed1989

Intestinal pseudo-obstruction due to dialysis amyloidosis.

Marked gastric dilatation and the carpal tunnel syndrome developed concurrently in a 58-year-old man treated with hemodialysis for 14 years. Despite extensive examinations, no attributable organic lesion was demonstrated in the gastrointestinal tract. However, amyloid deposition, which was immunohistochemically identified as beta-2 microglobulin, was demonstrated in the stomach and the synovia excised from the right carpal tunnel. Intestinal pseudo-obstruction due to dialysis amyloidosis was considered to be the cause of the gastric dilatation. There have been a few recently reported cases with dialysis amyloidosis in which extra-articular amyloid deposition resulted in overt clinical problems. The present case provides additional evidence that dialysis amyloidosis can develop serious extra-articular complications; intestinal pseudo-obstruction is a very rare gastrointestinal manifestation.

Amyloidosis↗
PubMed1988

Partial resection of atrial septal aneurysm with multiple fenestrations--a case report.

Aneurysms of the interatrial septum are uncommon lesions that are often accompanied by other cardiac anomalies or systemic thrombosis. The authors report 1 case of atrial septum aneurysm that was diagnosed by two-dimensional contrast echocardiography. At surgery a membrane-like, fenestrated aneurysmal protrusion to the right atrium without thrombosis was seen. The atrial septum was closed without using an artificial patch after some of the aneurysm with fenestrations was resected.

Adult↗