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Biomedical subjects

J Nakada

Publications and source records attributed to J Nakada.

At least 55 records · Page 3Linked to original sources
PubMed1986

Intra- and inter-nephron heterogeneity of gluconeogenesis in the rat: effects of chronic metabolic acidosis and potassium depletion.

The intra- and inter-nephron heterogeneity of renal gluconeogenesis within rat proximal tubules and the effects of chronic metabolic acidosis and chronic potassium(K)-depletion were studied using isolated proximal tubules of rats by directly measuring glucose synthesized. The gluconeogenic activity from pyruvate and glutamine in control rats was almost limited to within the early proximal tubule (S1: 45.4 +/- 5.7 pmol/mm/60 min from pyruvate; 58.0 +/- 6.0 from glutamine). Very low, but detectable gluconeogenesis was observed in the middle portion of the proximal tubule (S2: 9.9 +/- 2.2 from pyruvate; 4.8 +/- 1.1 from glutamine). The rate of glucose production in the terminal proximal tubule (S3) was negligible. Furthermore, gluconeogenesis from glutamine of superficial (SF) nephrons was significantly higher than that of juxtamedullary (JM) ones, whereas no difference was seen in gluconeogenesis from pyruvate. In acidotic and K-depleted rats, significant increase could be seen in S1 and S2, but the increase in S3 was not significant. By the serial determination in acidosis, the glucose production from both substrates was found to be the highest at the second 1 mm segment from the glomerulus, and it decreased downward along the proximal tubule. In acidosis, glucose production from both substrates in SF nephrons and that from glutamine in JM ones were elevated significantly compared with the control, but that from pyruvate in JM nephrons did not change. These results suggest that S1 of the SF nephron plays the most important role in gluconeogenesis in the control, whereas S1 of the JM nephron and S2 contribute to gluconeogenesis in acidotic and/or possibly K-depleted rats.

Acidosis↗
PubMed1986

Evidence that alpha-1-adrenergic stimuli specifically increase gluconeogenesis of the isolated proximal convoluted tubule in the rat.

Isolated kidney-cortical tubule suspensions and microdissected nephron segments from fed rats were used to study the action of catecholamines on gluconeogenesis. Gluconeogenesis from rat tubule suspension incubated with 5 mM pyruvate was stimulated maximally by 10(-5) M methoxamine, an alpha 1-selective agonist, and 10(-6) M noradrenaline by 29.2 +/- 5.2% (mean +/- SEM) and 32.6 +/- 2.9%, respectively. These effects were completely inhibited by 10(-7) M prazosin, a beta 1-selective antagonist. Yohimbine, an alpha 2-antagonist, also inhibited the effect, but only at a higher concentration (5 X 10(-5) M). Gluconeogenesis was not stimulated by isoproterenol, a alpha-agonist, at any concentrations between 10(-5) and 10(-7) M. With microdissected nephron segments, only the proximal tubule possessed gluconeogenic activity. Within the proximal tubule, the proximal convoluted tubule (PCT) revealed higher gluconeogenic activity than the proximal straight tubule (PST). Methoxamine at 10(-5) M stimulated gluconeogenesis in PCT, whereas in PST no increase of gluconeogenesis was observed. From these results, it can be concluded that an alpha 1-adrenergic agonist specifically stimulates renal gluconeogenesis in PCT, but not in PST.

Adrenergic alpha-Agonists↗
PubMed1985

Atrial natriuretic peptides stimulate renal gluconeogenesis.

Atrial natriuretic peptide (5-28AA; ANP) and atrial extract (ANS) stimulated rat renal gluconeogenesis in cortical tubule suspension in a dose dependent fashion only from substrates that enter gluconeogenesis via phosphoenol-pyruvate carboxylase. The effects of ANP and ANS were significantly potentiated by cAMP and cGMP, whereas methoxamine showed no effect. Extracellular calcium revealed a key role for ANP and ANS response to gluconeogenesis: a concentration of calcium higher than 1 mM was essential. Isolated cells from cortex which lost cell membrane polarity by warming but responded solely to cAMP and cGMP showed no effect by ANP nor ANS. These data suggest that ANP or ANS may act mainly from the basolateral site in the proximal tubule cell and promote gluconeogenesis through cAMP and/or cGMP system.

Animals↗
PubMed1985

[Acute myeloid leukemia with intracranial tumor formation--case report].

A 44-year-old house-wife was admitted to the hematological clinic of our hospital on December 21, 1981 for the treatment of acute myeloid leukemia. Hematological examination showed severe anemia, leukocytosis and thrombocytopenia. She was soon started on DCMP therapy (Daunomycin, Cytosine arabinoside, 6-MP and prednisolone). After several repeats of remission and aggravation, she suffered from vertigo, nausea and vomiting in early August of 1982. The CT scan and angiography showed a mass lesion in the middle of the posterior cranial fossa. On August 26, surgical extirpation of the tumor locating in the vermis of the cerebellum was performed successfully. On gross examination the tumor revealed smooth yellowish-red surface, elastic in consistency and measured 40 X 40 X 30 mm in size. Histologically it comprised the leukemic cells. The pathology of the central nervous system due to leukemic cells was discussed in relation to the pertinent literature, including the CT findings and the indication of the surgical treatment.

Adult↗
PubMed1985

[5-FU concentration in blood and tissue of patients with renal cell carcinoma after administration of UFT].

UFT (3 capsules; 300mg FT) was administered to five of 10 patients with renal cell carcinoma, and concentrations of FT, 5-FU and uracil in the serum and tissues (normal renal tissues, renal tumor tissues and liver) were determined 5.2 hours on average, after administration. The levels were also compared with these in the five patients administered 300 mg of FT. There was no difference in FT concentration between the serum and the tissues in the group administered UFT, but the concentration of 5-FU in tumor tissues was significantly higher (25.6 times) than that in the serum. The level was also higher (3.2 times) than that in normal renal tissues. There was a positive correlation between the concentration of 5-FU in the tissues and the concentration of uracil in the tissues. Although there was no difference in the concentration of FT between serum and tissues in patients administered UFT or FT, the concentration of 5-FU in patients administered UFT was definitely higher than that in patients administered FT; the concentration of 5-FU in the tumor tissues of patients given UFT was 3.9 times higher than in those given FT. Thus, UFT induced a concentration of 5-FU in tumor tissues that was maintained at a high level, suggesting that an excellent antitumor effect on renal cell carcinoma can be expected with UFT.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1985

[Clinical study of UFT in renal cell carcinoma].

A clinical study of UFT, a mixture of FT and uracil in a molar ratio of 1 : 4, was conducted on 12 patients with renal cell carcinoma. UFT was continuously administered at doses of 300, 400 or 600 mg per day. CR was recorded in 2 patients, PR in 2, NC in 7 and PD in 2, respectively. The overall response rate was 33.3%. Concerning side effects, 2 of the 12 patients suffered from anorexia and stomatitis, but no hepatic disorders or bone marrow suppression was observed. We concluded that UFT therapy was effective for renal cell carcinoma.

Administration, Oral↗
PubMed1985

[The role of preoperative embolization in renal cell carcinoma].

In 84 cases of renal cell carcinoma, the effect of embolization was assessed by dividing the patients into two groups: those having undergone (42 cases) or not having undergone (42 cases) embolization. A 16% decrease in tumor volume following embolization using an MMC-micro capsule was noted. In patients without metastasis at nephrectomy, a tendency was observed for the incidence of postoperative metastasis to be lower with more favorable survival for the group with embolization than that without. On the other hand, among cases with metastasis at nephrectomy, there were more patients who survived for a longer period in the embolization group.

Carcinoma, Renal Cell↗
PubMed1985

[Lymphadenectomy for renal cell carcinoma].

The techniques, results and problems of lymphadenectomy were assessed in 56 cases of renal cell carcinoma. As the approach to the retroperitoneum, the thoracoabdominal approach was used in 22 cases and transabdominal approach in 34 cases. Radical nephrectomy was performed, followed by lymphadenectomy. All of the regional lymph nodes were dissected. The mean time required for lymphadenectomy was 1 hour and 40 minutes and the mean volume of blood loss was 350 ml. As intraoperative complications, vascular injury occurred in 3 cases. In 1 of these cases the left second lumbar vein was injured. Therefore, in lymphadenectomy caution should be exercised not to give injury to this blood vessel. The postoperative complication observed included bleeding and chylous ascites in 1 case each. In performing operations one must ligate the lymphatic vessel carefully. The 5-year-survival rate for 6 cases associated with metastasis to lymph node was 33%. From this fact, it was postulated that lymphadenectomy is helpful to improve prognosis of these patients.

Adult↗
PubMed1984

Study of the venous phase on renal angiography in cases of renal carcinoma.

The venous phase on renal angiography was studied in 65 cases of renal carcinoma. Opacification of the renal vein stem was observed in 33 cases (51%). The visualisation rate of the renal vein was lower in high stage than in low stage tumours but there was no difference between these groups if patients with tumour thrombus of the renal vein were excluded from the high stage group. Renal arteriovenous fistulas were observed in six cases (9%), in three of which tumour thrombus of the renal vein was also seen. The thrombus was discovered at operation in 14 of the 65 cases and it was in 10 of these that the striated vascular pattern was observed on renal angiography. Collateral veins were observed in 15 cases (23%), only five of which had tumour thrombus of the renal vein.

Adult↗