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Biomedical subjects

M Nakamoto

Publications and source records attributed to M Nakamoto.

At least 37 records · Page 2Linked to original sources
PubMed1999

Effects of development on acetoacetyl-CoA synthetase biosynthesis in rat liver.

In order to investigate the physiological role of acetoacetyl-CoA synthetase (acetoacetate-CoA ligase, EC 6.2.1.16), a cytosolic acetoacetate-activating enzyme, the effects of animal development on the activity and content of the enzyme were examined in rat liver. In male rats, the enzyme specific activity increased 21-fold at 4 weeks of age from that at 2 weeks of age, and then gradually decreased, while in female rats, it increased similarly to that of male rats, but further increased, reaching a maximum about 3-fold higher than that of male rats, at 6 weeks of age. The developmental patterns of the enzyme content correlated with that of the enzyme specific activity. These results indicate that changes in this enzyme activity and content during the developmental process might influence the rate of ketone body utilization for the formation of physiologically important lipidic substances in rat liver.

Animals↗
PubMed1999

[Relationship between cancer chemotherapeutic drug-induced delayed emesis and plasma levels of substance P in two patients with small cell lung cancer].

We investigated the relationship between delayed emesis caused by cisplatin (CDDP) based chemotherapy and plasma levels of serotonin, 5-hydroxy-indoleacetic acid (5-HIAA), and substance P in two patients with small cell lung cancer. In each of the cases, we used the 5-HT3 receptor antagonist ramosetron every morning on day 1-4 of the chemotherapy. In case 1, plasma levels of serotonin were low, whereas substance P levels increased since 24 hours after the injection of CDDP. The increase in substance P levels paralleled the onset of vomiting. In this case, however, substance P levels decreased and yet vomiting occurred. Similarly, in case 2, plasma levels of serotonin were low, whereas substance P levels increased since 24 hours. The increase in plasma levels of substance P and the onset of vomiting were observed at the same time 2-3 days after cisplatin administration. In this case, however, vomiting was not observed during the 5 days when the substance P was highest. Therefore, we suggested that substance P was closely associated with CDDP-induced delayed emesis, though some chemical mediators other than substance P might also be related to the emesis.

Adult↗
PubMed1998

Early development of Epstein-Barr virus-associated T-cell lymphoma after a living-related renal transplantation.

We herein report a case of Epstein-Barr virus (EBV)-associated T-cell lymphoma that developed within a month after a kidney transplantation. The recipient was a 37-year-old man who had evidence of a previous EBV infection. Cyclosporine, methylprednisolone, and azathioprine were used for immunosuppression, and acute rejection was treated with high-dose methylprednisolone. The lactate dehydrogenase level started to increase on day 24 and thereafter peaked on day 37 while also demonstrating progressive jaundice and a bleeding tendency. A transplant nephrectomy was done on day 37; however, the patient could not recover and eventually died of respiratory failure as a result of diffuse pulmonary edema. A pathological examination of the resected kidney revealed a diffuse proliferation of large atypical lymphoid cells in the parenchyma. Immunohistochemically, the tumor cells were positive for CD45 and T-cell marker, CD45RO, but negative for B-cell markers. EBV-encoded RNA was demonstrated within the neoplastic cells by in situ hybridization.

Adult↗
PubMed1998

Retardation of skeletal development and cervical abnormalities in transgenic mice expressing a dominant-negative retinoic acid receptor in chondrogenic cells.

Skeletal formation is a fundamental element of body patterning and is strictly regulated both temporally and spatially by a variety of molecules. Among these, retinoic acid (RA) has been shown to be involved in normal skeletal development. However, its pleiotropic effects have caused difficulty in identifying its crucial target cells and molecular mechanisms for each effect. Development of cartilage primordia is an important process in defining the skeletal structures. To address the role of RA in skeletal formation, we have generated mice expressing a dominant-negative retinoic acid receptor (RAR) in chondrogenic cells by using the type II collagen alpha1 promoter, and we have analyzed their phenotypes. These mice exhibited small cartilage primordia during development and retarded skeletal formation in both embryonic and postnatal periods. They also showed selective degeneration in their cervical vertebrae combined with homeotic transformations, but not in their extremities. The cervical phenotypes are reminiscent of phenotypes involving homeobox genes. We found that the expression of Hoxa-4 was indeed reduced in the cartilage primordia of cervical vertebrae of embryonic day 12.5 embryos. These observations demonstrate that endogenous RA acts directly on chondrogenic cells to promote skeletal growth in both embryonic and growing periods, and it regulates the proper formation of cervical vertebrae. Furthermore, RA apparently specifies the identities of the cervical vertebrae through the regulation of homeobox genes in the chondrogenic cells. Great similarities of the phenotypes between our mice and reported RAR knockout mice revealed that chondrogenic cells are a principal RA target during complex cascades of skeletal development.

Animals↗
PubMed1998

Disadvantage of long-term CAPD for preserving cardiac performance: an echocardiographic study.

The indices of cardiac performances were compared between 31 continuous ambulatory peritoneal dialysis (CAPD) and 20 long-term hemodialysis (HD) patients. They were subdivided into three groups according to dialysis duration: L-CAPD (n = 16, mean age and CAPD duration were, respectively, 53 +/- 8 [SD] years and 77 +/- 13 months); S-CAPD (n = 15; 52 +/- 12 years, 28 +/- 12 months); HD (n = 20; 51 +/- 10 years, 162 +/- 52 months). The diabetic HD patients (DM-HD; n = 13; 60 +/- 13 years of age, 22 +/- 11 months) were chosen separately. Thirteen normotensive subjects with normal kidney function (mean age, 57 +/- 9 years) were selected as an age-matched control group. There were no significant differences between groups in age, gender, incidence of original kidney disease, or serum biochemical data. The blood pressure and the cardiothoracic ratio in L-CAPD were highest among groups. The indices of left ventricular (LV) hypertrophy as well as LV performance by means of echocardiography or pulsed Doppler were compared. Among nondiabetic dialysis patients, the calculated LV mass index (LVMI) of 166.4 +/- 84.3 g/m2 and the ratio of the peak atrial filling velocity to the peak diastolic flow velocity of 1.25 +/- 0.4 in L-CAPD were greatest, and the left ventricular fractional shortening (%FS) of 34.2 +/- 10.8% in L-CAPD was smallest. LVMI or %FS of L-CAPD was the same as DM-HD of 161.0 +/- 40.7 g/m2 or 31.6 +/- 8.2%. Possibly, poor control of hypervolemia, which is caused by peritoneal problems induced by either peritonitis or chronic exposure to high-glucose dialysate, causes a substantial cardiac preload leading to incipient cardiac failure in L-CAPD. According to the similar results of L-CAPD and DM-HD, it may be that hypertension, hyperlipidemia, or long-term constant glucose loading of CAPD fluids in addition to impaired glucose tolerance by chronic renal failure is more or less related to the progression of LV hypertrophy and latent cardiac dysfunction in long-term CAPD patients. In this context, CAPD of more than 5 years' duration is disadvantageous for preserving cardiac function as compared with HD.

Adult↗
PubMed1998

Image guidance of breast cancer surgery using 3-D ultrasound images and augmented reality visualization.

This paper describes augmented reality visualization for the guidance of breast-conservative cancer surgery using ultrasonic images acquired in the operating room just before surgical resection. By combining an optical three-dimensional (3-D) position sensor, the position and orientation of each ultrasonic cross section are precisely measured to reconstruct geometrically accurate 3-D tumor models from the acquired ultrasonic images. Similarly, the 3-D position and orientation of a video camera are obtained to integrate video and ultrasonic images in a geometrically accurate manner. Superimposing the 3-D tumor models onto live video images of the patient's breast enables the surgeon to perceive the exact 3-D position of the tumor, including irregular cancer invasions which cannot be perceived by touch, as if it were visible through the breast skin. Using the resultant visualization, the surgeon can determine the region for surgical resection in a more objective and accurate manner, thereby minimizing the risk of a relapse and maximizing breast conservation. The system was shown to be effective in experiments using phantom and clinical data.

Breast Neoplasms↗
PubMed1998

Interferon-induced anosmia in a patient with chronic hepatitis C.

We report a patient with chronic active hepatitis C developing acute anosmia during interferon (IFN) therapy. On July 31, he began receiving 6 MU of IFN-alpha daily. On September 26, he failed to smell gas leaking from a gas cooker, so IFN therapy was discontinued. He showed no reaction on a standard olfactory acuity test. As the patient had borderline diabetes, the association of anosmia with impaired glucose tolerance cannot completely be excluded, but his anosmia was probably induced by IFN therapy, since anosmia developed 10 days after the initiation of the IFN therapy, without any deterioration of his glucose intolerance.

Antiviral Agents↗
PubMed1998

Effects of room temperature, seasonal condition and food intake on finger skin temperature during cold exposure test for diagnosing hand-arm vibration syndrome.

For diagnosing the hand-arm vibration syndrome, peripheral circulation and sensory tests immersing one hand in cold water at 10 degrees C for 10 min have been performed widely in Japan. The authors investigated the effects of room temperature, seasonal condition and food intake on the test results, especially finger skin temperature. Six healthy males were examined repeatedly under six different room temperatures at 10 degrees C, 15 degrees C, 20 degrees C, 22.5 degrees C, 25 degrees C and 30 degrees C. Eight healthy males were examined under room temperatures at 10 degrees C, 20 degrees C and 30 degrees C, repeatedly in winter, spring, summer and autumn. Six healthy males were examined in summer under room temperature at 22.5 degrees C repeatedly 1 hr after, 3 hr after meal and after fasting for 13 hr. The finger skin temperature was strongly affected by room temperature. The finger skin temperature was also affected by seasonal condition. No remarkable effect of food intake was observed. For estimating circulatory function of the upper extremities using the finger skin temperature, the room temperature should be strictly controlled and the effect of seasonal condition must be taken into consideration.

Adult↗
PubMed1998

Can recovered protein from the CAPD patient's own dialysis effluent substitute for dextrose?

Albumin has been evaluated as an osmotic agent for peritoneal dialysis as being physiologically safe and having modest colloidal osmotic pressure. However its extremely high cost inhibits clinical applications, and hypoalbuminemia is often seen in continuous ambulatory peritoneal dialysis (CAPD) patients, especially those with high peritoneal equilibration test (PET) values and who lose a large quantity of albumin everyday. This study aims at recovering protein from CAPD effluent and reusing it safely at reasonable cost as a substitute for dextrose. The dialysis effluent was collected and concentrated with a semipermeable membrane. Uremic toxins and low-molecular-weight solutes were removed by repeated filtration and water dilution. The concentrate was acidified with hydrochloric acid down to pH 2, thence de-acidified with water dialysis up to pH 5. At this point, the isoelectric point of albumin, at which precipitate was deposited, the precipitate was separated from the supernatant and re-dissolved into electrolyte solution. The acidified concentrate exhaled an unpleasant odor, like that of decayed food. The precipitate solution, however, did not smell at all. The initial ultrafiltration rate of the recovered protein solution was measured and compared with that of dextrose and dextran by using a high-sensitivity differential manometer, one end of which was connected with the test solution cell, and the other with the serum cell. The ends were separated by a semipermeable membrane. The recovered protein solution at 20 g/dL concentration was almost equivalent in initial ultrafiltration rate to the 2.0 g/dL dextrose solution and to 20 g/dL dextran (MW: 75,000 dalton) solution.

Albumins↗
PubMed1998

Echocardiographic evaluation in long-term continuous ambulatory peritoneal dialysis compared with the hemodialysis patients.

In dialysis patients, the prevalence of severe left ventricular (LV) hypertrophy and systolic failure, important predictors of cardiovascular morbidity and mortality, has been reported to be very high. Therefore, we investigated cardiac function in 17 long-term CAPD patients (dialysis duration: 76.5 +/- 13.2 months; L-CAPD) by echocardiography and pulsed Doppler, and then compared with 16 short-term CAPD patients (dialysis duration: 28.9 +/- 11.9 months; S-CAPD), 21 long-term hemodialysis patients (dialysis duration: 165.1 +/- 52.7 months; L-HD), and 22 short-term hemodialysis patients (dialysis duration: 71.3 +/- 28.9 months; S-HD), except for the cases with diabetes mellitus, ischemic heart disease, cardiac surgery or overt congestive heart failure. We selected 13 normotensive patients with normal kidney function as normal control group matched for sex and age (Control). Concerning with L-CAPD, S-CAPD, L-HD, and S-HD, these four groups were matched for age and original diseases. We examined blood pressure (BP), cardiothoracic rate (CTR), antihypertensive (AHT) drugs and laboratory data. Wall thickness, left atrium, ventricular chamber size, ejection fraction (EF) and left ventricular mass (LV mass) [Devereux et al. 1986] were measured by echocardiograph. Peak early diastolic flow velocity (E), peak atrial filling velocity (A), A/E ratio and deceleration time of peak early diastolic flow velocity (DT) were calculated by analyzing transmitral flow, recorded by pulsed Doppler. BP control, CTR and EF were significantly worse in L-CAPD than in other patient groups. A/E as one of parameters for cardiac diastolic function was significantly higher in L-CAPD than in HD patients. LVMI (LV mass index: LV mass/body surface area) was significantly higher in L-CAPD than in other groups. LVMI in CAPD patients was shown to be significantly worse as time goes. Volume control by itself without AHT drugs could achieve good BP control in the long-term CAPD patients who were changed to maintenance hemodialysis because of peritoneal sclerosis. We concluded that LV hypertrophy and systolic dysfunction tend to progress in CAPD patients as time goes on. Also it is suggested that the cause of cardiac dysfunction in CAPD patients was mainly based on poor BP control probably due to overhydration, and therefore, appropriate volume control in CAPD patients is especially important.

Antihypertensive Agents↗
PubMed1998

Surgical treatments for orthopaedic complications in long-term haemodialysis patients--a review of 546 cases over the last 8 years.

We reviewed 546 operative cases in haemodialysis patients during the past 8 years between June 1990 and May 1998. The average age of the 257 male and the 289 female patients was 57.1 years. The average period of haemodialysis was 14 years and 4 months. We discussed the etiology, pathological focus, frequency, symptoms, problems and operative indications. Carpal tunnel syndrome occurred most frequently, occupying 289 cases. Short-term postoperative results were positive in the initial case within 6 months after the occurrence of the first symptoms. Because no effective method preventing recurrence existed, synovectomy was used as much as possible in the initial operation. Surgical treatment was used for amyloid arthropathy in 15 shoulders. It was effective in cases resistant to any conservative treatment. For the knee joint, the arthroscopic synovectomy was performed in 8 cases, and total knee replacement in 6 cases. The results of the total knee replacement cases were good. However, recurrences were observed in 40% of the synovectomy cases. In the hip joint, the curettage and bone grafting were performed in 7 hips of 6 patients. All bone grafts were consolidated and there was no case of postoperative pathological fracture. In some cases with destructive spondyloarthropathy, the vertebrae involved spontaneously fused without severe kyphotic deformity. A case with mild pain and without neurological deficit can be treated conservatively. A case with severe pain, instability, and myelopathy indicates operative measures must be taken. Attention must be paid for a possible collapse of the grafted bone after the cervical level two anterior fusion. Haemodialysis patients are vulnerable to infection. This diagnosis is difficult to distinguish due to the weakened state of the immune system. Rigorous attention is required to prevent and detect infection in cases using artificial joints or instrumentation. The treatment of bone and joint disturbances from dialysis-related amyloidosis has become surgical due to the advancement of dialysis control. However, it remains one of the more conservative treatments. Determining the cause and establishing a method of treatment are desired as early as possible.

Adult↗
PubMed1998

[Successful removal of a left ventricular fibroma in a 10-year-old patient].

A 10-year-old girl with negative T wave in leads I, II, III, aVF, and V2-6 in the ECG was examined. The two-dimensional echocardiogram and the MRI revealed that she had a tumor in the free wall near the apex of the left ventricle. We removed the intramural fibroma (50 x 35 x 30 mm) of the left ventricle under cardiopulmonary bypass very carefully not to perforate the left ventricular cavity. After the removal, the defect was repaired by the sutures of the myocardial layers so that the volume inside the left ventricle could be kept and its shape could be maintained. She has been doing well without any trouble for 5 months after the operation.

Cardiac Surgical Procedures↗
PubMed1998

Acute renal failure due to hypokalemic rhabdomyolysis in Gitelman's syndrome.

A 46-year-old-male developed acute renal failure (ARF) secondary to hypokalemic rhabdomyolysis. Potassium supplementation restored renal function following improvement of the rhabdomyolysis. After recovery from ARF, further evaluation disclosed he had hypokalemic metabolic alkalosis, normotensive hyperreninemia, hyperaldosteronism, renal hypomagnesemia, hypocalciuria and hyperplasia of the juxtaglomerular apparatus which are a diagnostic set of disorders in Gitelman's syndrome, a variant of Bartter's syndrome. This is the first reported case of ARF due to hypokalemic rhabdomyolysis associated with Gitelman's syndrome.

Acute Kidney Injury↗