Effects of very-low-calorie diet weight reduction on glucose tolerance, insulin secretion, and insulin resistance in obese non-insulin-dependent diabetics

We put 12 obese subjects on a very-low-calorie diet (VLCD) and observed how their weight loss affected their glucose tolerance. Seven had non-insulin-dependent diabetes and five did not. They consumed 1000 kcal/day for at least 1 week, then 420 kcal/day for 4 weeks, and 1000 kcal/day thereafter. VLCD improved glucose tolerance and insulin response to a glucose load in the diabetics and did not affect these parameters in the non-diabetics. It did not change insulin responsiveness to intravenous glucagon in either group. Both groups showed improved insulin resistance, as measured by an insulin suppression test. Regression analysis showed that insulin resistance correlates well with obesity and glycemic control. Weight reduction did not change hepatic insulin extraction. Thus, the improvement in glucose tolerance by some of the diabetics seems to have arisen from improvements in their insulin resistance and insulin response to a glucose load. Insulin resistance improved because of weight reduction and subsequent improvements in glycemic control.

Comparisons of maltase activities in kidney brush border membranes from normal, diabetic, glucose-infused and maltose-infused rabbits

The specific activities of membrane-bound maltase (alpha-D-glucoside glucohydrolase, EC 3.2.1.20) in isolated brush border membranes (BBMs) of alloxan-induced diabetic, glucose-infused and maltose-infused rabbits were 30%, 140% and 160%, respectively, of those of control rabbits. Differences in the relative activities of trehalase (EC 3.2.1.28), another disaccharidase, in these groups were similar but less marked. However, the activities of two other marker enzymes of the brush border, alkaline-phosphatase and gamma-glutamyl transpeptidase, were similar in the 4 groups of rabbits. The decreases in the activities of the two disaccharidases were due to changes in the Vmax values of the enzymes without change in their Km values for maltose and trehalose. The maltase activities in the 4 groups showed similar dependences on Tris-HCl, KCl and NaCl. The electrophoretic profiles of the BBMs of the 4 groups on SDS-polyacrylamide gel showed slight differences. From these results, we conclude that diabetes, glucose infusion and maltose infusion probably change the concentrations of active enzymes in the BBM of the kidney in rabbits.

Nephrectomy in renal carcinoma with distant metastasis

A total of 96 cases of renal carcinoma with distant metastasis at the time of diagnosis was studied. The patients were classified into 4 groups: Group O (16) in whom nephrectomy was not performed, Group A (51) who died due to carcinoma within 1 year of nephrectomy, Group B (25) who died due to carcinoma 1 to 3 years after nephrectomy, and Group C (4) who survived for 3 years or more after nephrectomy. Six clinical measurements were evaluated: haemoglobin, ESR, alpha 2 globulin, temperature, weight and C reactive protein. In addition, performance status, the number of organs with metastases, number of metastatic lesions and tumour growth rate were measured. The results showed that in patients surviving for 1 year or more after nephrectomy, there was an abnormality in the results of 3 or less of the 6 clinical measurements, performance was 0 or 1, and the carcinoma had metastasised to only one organ. In addition, it was found that the growth of metastatic lesions in patients who survived for 3 years or more was much slower than in the other patients. Nephrectomy was found to be effective in only 27% of our cases and we consider that careful deliberation should be made pre-operatively as to whether nephrectomy is really necessary in patients with metastasis. The decision should be made on the basis of the results obtained in the 6 clinical measurements given above.

Hyperthermia with simultaneous administration of interferon using established human renal carcinoma heterotransplanted in nude mice

Using human renal carcinoma heterotransplanted in nude mice, the effects of the combined use of hyperthermia and interferon (natural human interferon-alpha; IFN-alpha, and recombinant interferon-gamma; IFN-gamma) were examined. The hyperthermic device used was the Clini-Therm, Mark VII, 915 MHz, microwave. The administration of interferon was started immediately before hyperthermia and carried out on consecutive days. The combined use of hyperthermia and IFN was compared with hyperthermia and with IFN alone. The combined use of hyperthermia and IFN-alpha was shown to have significant anti-tumour effects compared with the former or latter alone. Of 10 nude mice (10 implanted tumours) used for the experiment, 5 showed complete disappearance of the implanted tumours and the others showed prolongation of survival. Combined treatment with IFN-gamma and hyperthermia showed no significant effect when compared with other treatment groups. Combined treatment with local hyperthermia and IFN-alpha may have some application to the clinical management of renal carcinoma.

Low density lipoprotein and apoprotein B induce increases in inositol trisphosphate and cytosolic free Ca2+ via pertussis toxin-sensitive GTP-binding protein in vascular smooth muscle cells

Low density lipoprotein (LDL), a major cholesterol-carrying lipoprotein in the plasma, binds to its receptor through apoprotein B (Apo-B). The addition of LDL and Apo-B induced rapid (5 s), but transient increase in the inositol 1,4,5-trisphosphate (Ins-1,4,5-P3) level with K0.5 values of 1.1 and 0.07 microgram/ml, accompanied by increases of cytosolic free Ca2+ concentration [( Ca2+]i), in vascular smooth muscle cells (VSMC). The increases by LDL and Apo-B were both reduced by pretreatment of the VSMC with pertussis toxin. The early change in Ins-1,4,5-P3 involving a GTP-binding protein may function as an initial signal for the action of LDL in VSMC.

Association of increased intracellular free Ca2+ by platelet-derived growth factor with mitogenesis but not with proteoglycan synthesis in chondrocytes--effect of suramin

The effects of platelet-derived growth factor (PDGF) on the intracellular free Ca2+ concentration [( Ca2+]i) in chondrocytes were studied with a fluorescent Ca2+ indicator, fura 2, and compared with the effects of PDGF on mitogenesis and proteoglycan synthesis. PDGF evoked phasic and then tonic increase in [Ca2+]i dose-dependently in quiescent cultures of chondrocytes, and it also stimulated both DNA and proteoglycan syntheses dose-dependently similar to somatomedins. Suramin, which inhibits the interaction of PDGF with its receptors, caused dose-dependent inhibition of both the PDGF-evoked increase in [Ca2+]i and stimulation of DNA synthesis by PDGF. However, suramin rather enhanced the proteoglycan synthesis induced by PDGF without affecting the basal level of proteoglycan synthesis directly. These results suggest that [Ca2+]i may be an important signal for the action of PDGF on cell proliferation in chondrocytes, and that the initial signal for proteoglycan synthesis is different from that for DNA synthesis induced by PDGF after the activation of PDGF receptor.

[Dysplasia of the gallbladder]

Out of 2,027 resected gallbladders that were examined, 46 (2.2%) manifested dysplasia and, to study this further, step sections, 5 mm apart, were performed. The average age of these dysplastic cases was 63.8 years, with a male to female ratio of 1:3. The most frequent dysplastic sites in the gallbladder were in the fundus and the body. Excluding adenomas, polypoid lesions, the dysplasia appeared flat, granular, or irregular. As to diameter, 68.6% were within 1 cm, and 89% were no more than 2 cm. The majority of cases manifesting mild dysplasia had lesions of up to 5 mm in size while the lesions seen in moderate cases were within 2 cm. Stones were found in 80.4% of the cases, and incidences of intestinal metaplasia and pseudopyloric gland metaplasia were found in 80.4% and 100% of these cases, respectively. Incidences of dysplasia adjacent to the carcinoma was seen in 41.8% of the cases, and frequently found in early-stage lesions and well-differentiated carcinomas. Our findings have led us to believe that recognition of the intestinal metaplasia-dysplasia-carcinoma sequence is important.

Effects of glycyrrhizin and glycyrrhetinic acid on (Na+ + K+)-ATPase of renal basolateral membranes in vitro

Studies were made on the direct effects of glycyrrhizin and its aglycone, glycyrrhetinic acid on the activities of (Na+ + K+)-ATPase and (Ca2+ + Mg2+)-ATPase, a membrane bound Na+ and Ca2+-extrusion pump enzyme of the basolateral membranes (BLM) of canine kidney. Glycyrrhetinic acid inhibited the activity of the Na+-pump enzyme dose-dependently (IC50 = 1.5 x 10(-4) M), but had no effect on that of the Ca2+-pump enzyme of kidney BLM and homogenates. Glycyrrhizin also inhibited the Na+-pump enzyme activity but had less effect (IC50 = 2 x 10(-3) M). The effects of these compounds were due to competitive inhibition with ATP binding to the enzyme (Ki = 12 microM) and so were different from that of ouabain, which inhibits the Na+-pump by binding to its extracellular K+-binding site. The direct effect of glycyrrhetinic acid on the membrane may be important role in the multiple actions of licorice.

A patient with hypogonadotropic hypogonadism successfully treated by long-term pulsatile administration of luteinizing hormone-releasing hormone

A male patient with hypogonadotropic hypogonadism has been treated by pulsatile administration lf luteinizing hormone-releasing hormone (LHRH) (20-25 micrograms, every 2 hours, sc) for 4 years 6 months. His plasma testosterone (T) concentration began to increase after 4 weeks of treatment and reached the normal range in week 5. He showed complete secondary sexual development after 1 year of treatment. His sperm count was normalized after 1 year of treatment. He was married after 29 months of therapy, and has a healthy male child. Blood type tests showed his paternity of the child. During the long duration of pulsatile LHRH therapy, his gonadotropin secretion has been stimulated by LHRH and his T level has been maintained with no observable side effects. There are no other reports of patients treated by pulsatile LHRH injection for such a long duration, but finding in this patient indicated that long-term pulsatile LHRH therapy is a useful and safe method for treatment of hypothalamic hypogonadotropic hypogonadism.

Changes in prolactinomas and somatotropinomas in humans treated with bromocriptine

Effects of bromocriptine (CB) on human prolactin (PRL)-secreting adenomas (PRLomas) and growth hormone-secreting adenomas (GHomas) were analyzed morphologically and morphometrically. Treatment with CB for 2 weeks brought about a variety of changes in PRLomas, including cell shrinkage, degenerative and necrotic changes and fibrosis. Secretory granules within a cell increased in number but not in volume. However, the exocytosis of the granules increased remarkably. Single-cell necrosis was occasionally seen in the tumor nests, whereas breakdown of tumor cells occurred in clusters predominantly in the periphery of the nests. At 1 week after cessation of CB, PRLomas showed two distinct, divergent histological appearances; more advanced destructive changes and the regrowth. These findings suggest that human PRLomas consist of two populations, i.e., those sensitive and resistant to the cytocidal actions of CB. In contrast, treatment with CB produced almost no change in GHomas except for an increase in the stromal tissue volume. Vacuolation and single-cell necrosis were occasionally observed in a few GHomas.

[Unexpected renal cell carcinomas found during the operation in renal calculus: report of two cases]

Case 1: A 58-year-old man was seen with dull pain over the left flank. The X-ray examination revealed a renal stone in the left kidney. On operation, a globular hard mass was found in the lower portion of the posterior aspect of the kidney from which a biopsy specimen was obtained. A frozen section study showed renal cell carcinoma, and nephrectomy was performed. The patient is well four years after the operation without recurrence or metastasis. Case 2: A 50-year-old man consulted with microhematuria pointed out in a physical examination. At the operation for renal stone, we found the mass in the lower portion of the kidney. A frozen section study of the mass revealed renal cell carcinoma. We performed nephrectomy and lymphadenectomy on the renal pedicle. The patient is well three years after the operation. We reviewed the cases of renal cell carcinoma associated with renal calculi reported in Japan and discussed how the nephrectomy should be performed according to the frozen section study.

[Immunoreactive parathyroid hormones in the circulation and cerebrospinal fluid from patients with renal failure: possible restriction of parathyroid hormone by the blood-brain barrier]

There are reports that patients with renal failure have elevated circulating concentrations of parathyroid hormone (PTH), which is suspected to be a causal factor of the cerebral symptoms of these patients. A positive correlation between the circulating level of immunoreactive PTH and the extent of abnormality in the electroencephalogram (EEG) in humans has been reported. Moreover, in uremic dogs normalization of the EEG was observed after parathyroidectomy, and increased abnormality of the EEG was observed on infusion of PTH. If PTH is really a causal factor of uremic encephalopathy and abnormality of the EEG in patients with renal failure, the question arises as to whether PTH acts on the brain after penetrating through the blood-brain barrier or in some other way. In this work, we measured PTH by both C-terminal-specific RIA (C-PTH) and N-terminal-specific RIA (N-PTH) in the circulation and cerebrospinal fluid (CSF) of normal subjects and patients with renal failure. Blood and CSF samples were obtained from 7 normal volunteers (31 approximately 81 years old: 4 males and 3 females) and 22 patients with chronic renal failure (25 approximately 87 years old: 12 males and 10 females). No patients had a psychotic disease or endocrinopathy other than secondary hyperparathyroidism. Samples of venous blood were collected from the subjects after an overnight fast at the time of lumbar puncture for CSF sampling. C-terminal-specific RIA for measurement of the plasma and CSF concentrations of C-PTH was carried out using a commercially available RIA kit (Eiken Laboratory Inc., Tokyo, Japan).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of estrogens on renal responsiveness to parathyroid hormone in elderly female subjects

The effect of estrogens on the renal responsiveness to parathyroid hormone (PTH) was examined by PTH loading tests with synthetic human-PTH (1-34) in 8 normal elderly females (mean +/- SD age, 81.0 +/- 7.1 yr) before and after administration of estrogen (Premarin 1.25 mg/day for 4 weeks). Basal urinary adenosine cyclic 3', 5'-monophosphate (cAMP) excretion showed a tendency to increase after estrogen administration (5.47 +/- 1.68 vs 6.60 +/- 2.67 nmol/100 ml GFR) and the theoretical renal phosphorous threshold showed a tendency to decrease from 3.22 +/- 0.98 to 2.73 +/- 0.56 mg/dl. The blood ionized calcium concentration did not change after estrogen administration (4.44 +/- 0.16 vs 4.32 +/- 0.20 mg/dl) and serum phosphorous (P) decreased significantly (3.65 +/- 0.47 vs 3.01 +/- 0.42 mg/dl, p less than 0.05). There was no increase in mean serum immunoreactive PTH (0.34 +/- 0.10 vs 0.34 +/- 0.05 ngeq/ml). The urinary excretions of cAMP in response to PTH loading [100 U of human-PTH (1-34), intravenously] significantly (p less than 0.05) increased (94.8 +/- 57.0 vs 196.7 +/- 118.3 nmol/100 ml GFR/h) after estrogen administration. Moreover the changes in urinary excretion of cAMP (r = 0.698, p less than 0.01) and P (r = 0.555, p less than 0.05) induced by the PTH loading were positively correlated with serum estradiol in elderly females, assessed as groups before and after estrogen administration. These results suggest that estrogens may enhance the renal responsiveness to exogenous PTH administration.

Increase of (Ca2+ +Mg2+)-ATPase activity of renal basolateral membranes by platelet-derived growth factor through a specific receptor

Studies were made on the direct effect of platelet-derived growth factor (PDGF) on the high-affinity (Ca2+ +Mg2+)-ATPase, a membrane bound Ca2+-extrusion pump enzyme of the basolateral membranes (BLM) of canine kidney (Km for free Ca2+ = 1.0 x 10(-7) M, Vmax = 180 nmol Pi/mg/min). At 1 x 10(-7) M free Ca2+, PDGF (10(-10)-10(-8) M) stimulated the enzyme activity significantly. Addition of 5 - 200 microM suramin, a compound that blocks binding of PDGF to its receptors on cell membranes, inhibited the stimulatory effect of PDGF dose-dependently (IC50 = 40 microM). A high affinity specific receptor for PDGF (Kd = 4.4 x 10(-10) M, Bmax = 460 fmol/mg protein) was detected on BLM preparations by radioreceptor assay with 125I-PDGF and unlabelled PDGF. Suramin (10-1000 microM) also inhibited the binding of PDGF to BLM preparations dose-dependently. From these results, it is proposed that PDGF stimulates (Ca2+ +Mg2+)-ATPase activity of kidney BLM preparations by enhancing its affinity for free Ca2+ through a specific receptor.

[Anti-tumour effect of UFT on human renal cell carcinoma heterotransplanted into nude mice]

1) Using two histologically different human renal cell carcinomas heterotransplanted into nude mice, the antitumour effect of UFT was investigated, and an attempt was made to analyze the properties of the tumour strains where a drug efficacy was noted. 2) The two strains used were the JRC 1 strain (tumour doubling time of 9.4 days, clear cell type, papillary histologic pattern, grade 3) and the JRC 11 strain (tumour doubling time of 2.72 days, granular cell type, anaplastic histologic pattern, grade 4). 3) Two dose groups were set up, one receiving 10 mg/kg of tegafur (FT) and 22.4 mg/kg of uracil and the other receiving 20 mg/kg of FT and 44.8 mg/kg of uracil. Each group was further divided into an early administration group (start of administration 3 days after the tumour transplantation) and a late administration group (start of administration at a time when the transplanted tumour proliferated to weight of 100 to 300 mg). 4) Effect as noted in the tumour proliferation inhibition rate was seen only in the group receiving 20 mg/kg of FT and 44.8 mg/kg of uracil in both early and late administration groups of the JRC 1 strain. Among these groups only the early administration groups showed a histological positive effect. 5) The fact that the measured 5-FU intra-tumour concentration in the JRC 1 strain was only 1/4 that of the JRC 11 strain demonstrates more susceptibility of JRC 1 strain to UFT. Moreover, intratumoral concentration of 5-FU differed markedly even with the same administration method and dosage level. This result indicates that intra-tumour concentration will be different if the histological pattern differs.

Plasma calcitonin in rats with renal failure

To study the effect of the kidney on blood calcitonin (CT), rats were made uremic by either total or partial nephrectomy or bilateral ligation of the ureters. Plasma CT concentrations were measured by radioimmunoassay before and after calcium infusion. Uremia induced by total or partial nephrectomy produced an increase in plasma CT. Rats had higher plasma CT levels (49.3 +/- 1.7 pg/ml, mean +/- SE) after total nephrectomy than after ureteral ligation (30.9 +/- 1.5 pg/ml) even though no significant difference was observed between the blood urea nitrogen (BUN) levels of these two groups. These results indicate that the kidney contributes to the degradation of CT.