Patients with renal hypouricemia with exercise-induced acute renal failure and chronic renal dysfunction.

We here report the case of a 38-year-old male with back pain and vomiting occurring after exercise. Serum creatinine level was elevated, and he was admitted to our hospital with diagnosis of acute renal failure (ARF). He had experienced similar attacks at least 4 times, including the present episode, from the age of 22 years. After admission, the patient was managed only by resting, and remission was nearly attained in about 1 month. The renal biopsy specimen performed on day 15 showed findings of acute tubular necrosis, thickening of the tubular basement membrane, and interstitial fibrosis. After remission, the serum uric acid level was 0.7-0.8 mg/dl, fractional excretion of uric acid was 0.63, and the possibility of other diseases facilitating the excretion of uric acid was denied. Therefore, ARF associated with idiopathic renal hypouricemia was diagnosed. Since only mild responses were observed in a pyradinamide loading test and a benzbromarone loading test, the case was considered to be a presecretary reabsorption disorder type. Renal function tests showed the almost complete recovery of the glomerular filtration rate (GFR: 114 ml/min/1.73 m2), but the urine concentrating ability was markedly decreased (specific gravity 1.019 and osmolarity 516 mOsm/kgxH2O in Fishberg test). Past data from this patient indicated that this renal dysfunction had been persisting for ten years. We examined 9 patients with renal hypouricemia and focused on the differences between the two groups (with or without complications). Four patients had a history of exercise-induced ARF or calculus. The urine concentrating ability was significantly lower in these patients (group A) than in the other patients without complications (group B). The glomerular filtration rate in group A was within the normal range, but was lower than in group B. These results suggested the possibility that patients with renal hypouricemia with complications may have chronic renal dysfunction in the future.

Decreased expression of nucleoside diphosphate kinase alpha isoform, an nm23-H2 gene homolog, is associated with metastatic potential of rat mammary-adenocarcinoma cells.

The nm23 gene [encoding nucleoside diphosphate kinase (NDPK)] may act as a metastasis suppressor in certain tumor cells. We investigated the role of NDPK isoforms (alpha and beta) in the metastatic processes, using rat mammary-adenocarcinoma cell lines of poor (MTC) and high (MTLn3) spontaneous metastatic potential respectively. In these cell lines, as in most rat tissues, the alpha isoform (nm23-H2 homolog) was more highly expressed than the beta isoform (nm23-H1 homolog) at the mRNA and protein levels. When examined by Northern- and Western-blot analyses, expression of the 2 isoforms was reduced in highly metastatic MTLn3 cells compared with poorly metastatic MTC cells. The reduced expression was also associated with diminished NDPK-enzyme activity in the cell extracts. Southern-blot and RT-PCR-SSCP analyses suggested that the 2 genes were not grossly altered or mutated in their translation regions. MTLn3 cell clones transfected with NDPKalpha or NDPKbeta cDNA were all tumorigenic when implanted into the mammary fat pad of syngeneic rats. Among those, only clones transfected with the NDPKalpha gene exhibited reduced lung metastasis in a spontaneous metastasis assay.

Bisphosphonates act on osteoblastic cells and inhibit osteoclast formation in mouse marrow cultures.

We examined the mode of action of bisphosphonates on osteoclastic cell recruitment using mouse marrow cultures with or without osteoblastic cells. Tartrate-resistant acid phosphatase-positive multinucleated cells [TRAP(+)MNC] formed in cultures were determined to be osteoclastic cells. In marrow cultures, TRAP(+) MNC formation in the presence of 10(-8) mol/L 1,25(OH)2D3 was not affected by the addition of 10(-6) mol/L dihydrogen (cycloheptylamino)-methylenebisphosphonate monohydrate (YM175). However, it was inhibited in cocultures of marrow cells with osteoblastic cells. The inhibitory effect was evident throughout the entire culture period. YM175 dose dependently inhibited TRAP(+) MNC formation, and other bisphosphonates--pamidronate and alendronate--also inhibited TRAP(+) MNC formation in the coculture. Similar observations were also made in the coculture of spleen cells with osteoblastic cells. The conditioned media of osteoblastic cells treated with 10(-6) mol/L YM175 inhibited TRAP(+) MNC formation in marrow cultures. The presence of YM175 in methylcellulose cultures affected neither the colony formation of monocyte-macrophage lineage, nor TRAP(+) MNC formation in the succeeding cocultures of recovered cells with osteoblastic cells. These results indicate that YM175 and probably other bisphosphonates as well preferentially inhibit the later stage of osteoclastogenesis through its action on osteoblastic cells. Our findings suggest that part of the inhibitory action by osteoblastic cells in the presence of bisphosphonates is mediated through soluble factor(s).

Non-cushingoid Cushing's syndrome due to adrenocorticotropic hormone-independent bilateral adrenocortical macronodular hyperplasia.

This case report describes a 68-year-old man with Cushing's syndrome due to adrenocorticotropic hormone (ACTH)-independent bilateral adrenocortical macronodular hyperplasia (AIMAH). He was referred to our hospital for evaluation of bilateral enlargement of the adrenal glands found incidentally by computed tomography (CT). He had a ten-year history of hypertension. Although he was normokalemic and did not show Cushingoid features, the diagnosis of ACTH-independent Cushing's syndrome was established by endocrinological examinations. His plasma cortisol showed no diurnal rhythm and was unsuppressible by high-dose (8 mg/day) dexamethasone. Plasma ACTH was undetectable and did not respond to corticotropin-releasing hormone. Excised adrenal glands were markedly enlarged (right 28 g and left 64 g). Macroscopic appearance of the glands showed multiple yellowish nodules typical for AIMAH; microscopic findings were also compatible with AIMAH. The present case indicates that patients with AIMAH sometimes do not show typical Cushingoid features and therefore AIMAH can be found incidentally from ultrasound or CT examination of the abdomen.

Changes of bone metabolic markers in patients with bone metastases: clinical significance in assessing bone response to chemotherapy.

To determine the changes in bone metabolism in response to combined chemotherapy in patients with bone metastases (BM), we examined osteocalcin (BGP), alkaline-phosphatase (ALP), hydroxyproline (HYP), pyridinoline (PYR), and/or deoxypyridinoline (D-PYR) in 25 cancer patients. In patients without BM, serum BGP was normal and not affected by chemotherapy. In patients with BM, however, BGP was often abnormally high or low, and some patients reacted to chemotherapy with a BGP increase at 4 weeks after initiation of therapy. Such an increase was observed in the group of patients who responded favorably to therapy as judged by a decrease in bone pain and tumor-associated biochemical markers. Urine HYP, PYR, and D-PYR were high in patients with BM before therapy; D-PYR decreased transiently at 2 weeks and increased thereafter. We assume that increased bone-resorption markers along with increased bone formation markers after therapy would indicate recovery of coupled bone metabolism, as the deranged bone remodeling is improved by tumor-regression. This study suggests that BGP and D-PYR can be useful early markers to predict favorable bone response to chemotherapy in patients with BM.

Estradiol up-regulates the stimulatory GTP-binding protein expression in the MCF-7 human mammary carcinoma cell line.

The effect of estradiol treatment of the human mammary carcinoma cell MCF-7 on the adenylyl cyclase system was examined. Treatment with 10 nM estradiol for 72 h increased the basal level of cAMP, and isoproterenol-, PGE2- or calcitonin-stimulated cAMP production. Estradiol also increased the response to cholera toxin but did not alter the response to forskolin. No significant change in growth rate was observed during the 72 h of estradiol treatment. In MCF-7 cell membranes the responsiveness to isoproterenol, PGE2, or cholera toxin was also enhanced by estradiol treatment. The cholera toxin-catalyzed ADP-ribosylation of Gs alpha in MCF-7 cell membranes was significantly increased by 72 h of treatment with estradiol. Consistent with this observation, the level of Gs alpha immunoreactivity was increased in the estradiol-treated cell membranes. On the other hand, pertussis toxin did not change the responsiveness to isoproterenol, PGE2 or calcitonin in either control or estradiol-treated cells. In addition, ADP-ribosylation with pertussis toxin also did not reveal any change in Gi. These results clearly indicate that Gs expression is under the control of estradiol, and that this effect may contribute to the increased sensitivity of hormone-stimulated adenylyl cyclase activities in MCF-7 cells.

[Parathyroid hormone and calcitonin].

Parathyroid hormone (PTH) is essential for the physiologic maintenance of mineral homeostasis. PTH regulates the mineral transport in bone and kidney and through its secondary actions on mineral transport in intestine (mediated by 1.25 (OH)2D). Calcitonin, in many ways, acts as a physiologic antagonist to PTH. Recently the techniques of molecular biology have been applied to the study of these hormones and more precise mechanism of action of these hormones has been elucidated. Last year both PTH receptor and calcitonin receptor were cloned. This review briefly summarizes new informations about their biosynthesis, secretion, metabolism, action, and structures of their receptors.

Simultaneous occurrence of SIADH, secondary hypogonadism and alopecia universalis in a woman with IDDM.

Syndrome of inappropriate secretion of antidiuretic hormone (SIADH), hypothalamic hypogonadism and alopecia universalis occurred in a 31-year-old female with insulin-dependent diabetes mellitus (IDDM). Despite various clinical investigations and careful observation for 20 months, the cause and pathogenesis of SIADH and hypothalamic hypogonadism were not elucidated. The complex of these disorders had not been described. The presence of IDDM and alopecia universalis, in which an autoimmune process has been assumed to be involved, is interesting in considering the pathogenesis of the SIADH and hypothalamic hypogonadism.

The effect of PGF2 alpha on parathyroid hormone-stimulated cyclic AMP production in mouse osteoblastic cell, MC3T3E1.

The effect of prostaglandin F2 alpha (PGF2 alpha) was investigated in MC3T3E1 cells on the succeeding cAMP response to parathyroid hormone (PTH). PGF2 alpha increased the membrane-associated protein kinase C (PKC) activity, indicating the activation of this enzyme. The effect of PTH to increase cAMP production was enhanced by pretreatment with PGF2 alpha. Phorbol 12-myristate 13-acetate also enhanced cAMP production stimulated by PTH, and PKC inhibitor H7 attenuated the enhancement of PGF2 alpha. A23187 did not reproduce the PGF2 alpha effect, and this effect was not antagonized by the calmodulin antagonist W7. PGF2 alpha did not change the ED50 nor the maximally responsive dose of PTH in stimulating cAMP production. The effect of PGF2 alpha was not affected by pertussis toxin, and PGF2 alpha also enhanced cholera toxin- or forskolin-stimulated cAMP production. In accordance with the response of cAMP to PTH, the resorption of mouse limb bones stimulated submaximally by PTH was enhanced by the concomitant presence of PGF2 alpha. These results indicate that PGF2 alpha modulates cAMP response through the activation of PKC, the target of which might be the catalytic unit of adenylate cyclase. Such interaction between signal transduction systems may have significance in modulating the effect of PTH on bone, i.e., bone resorption.

Purification and partial sequencing of inhibitory factor on renal membrane adenylate cyclase in pancreatic cancer extract: identity with histones H1b or H1d.

Inhibitory activity on renal membrane adenylate cyclase (AC) has previously been found in the extract of a pancreatic cancer associated with humoral hypercalcemia of malignancy (HHM). AC inhibitor was purified employing inhibition of AC activity of renal membrane stimulated by forskolin as its index. N-terminal 9 residues and a digested fragment of purified protein (14 residues) were completely consistent with that of histones H1b and H1d. Not only histone H1 but also histones H2A, H2B and H3 from calf thymus inhibited AC activity. These results indicate that the AC inhibitor in the pancreatic cancer extract is histone H1b or H1d and histones H2A, H2B and H3 also have an AC inhibitory activity.

Inhibition of estradiol uptake and transforming growth factor alpha secretion in human breast cancer cell line MCF-7 by an alkyl-lysophospholipid.

We investigated the effect of 1-O-octadecyl-2-O-methyl-sn-glycero-3-phosphocholine (ET-18-OCH3), an alkyl-lysophospholipid, on the uptake of estrogen, the secretion of transforming growth factor (TGF) alpha and the content of progesterone receptors (PRs) in the hormone-dependent breast cancer cell line, MCF-7. The uptake of labeled estradiol by MCF-7 was dose dependently decreased by 12 h pretreatment with 10-25 micrograms/ml ET-18-OCH3, and this suppression occurred prior to the onset of the inhibitory action of ET-18-OCH3 on MCF-7 growth. Scatchard analysis demonstrated that ET-18-OCH3 reduced the number of estrogen receptors in MCF-7 without affecting their affinity. Both the secretion of TGF-alpha from MCF-7 into the conditioned medium and the PR content of MCF-7 were decreased by 48 h treatment with 10 micrograms/ml ET-18-OCH3. The estradiol uptake, the TGF-alpha secretion, and the PR content were not affected by platelet-activating factor, lyso-PAF, and palmitoyl-lysophosphatidylcholine, all at 10 micrograms/ml. These results suggest that the reduction of estrogen receptor level induced by ET-18-OCH3 resulted in decreases in both the secretion of TGF-alpha and the content of PR in MCF-7, and these effects are specific to ET-18-OCH3. We concluded that these effects of ET-18-OCH3 may lead, at least partly, to its antitumor action in hormone-dependent breast cancer cell lines.

Inhibition of renal membrane adenylate cyclase by extract of pancreatic cancer associated with humoral hypercalcemia of malignancy.

The parathyroid hormone (PTH)-like activity, defined by the stimulation of cAMP production in MC3T3E1 cells, in the extract of a pancreatic cancer associated with humoral hypercalcemia of malignancy (HHM) was eluted in two peaks (I and II) by reverse phase HPLC. Both peaks dose-dependently inhibited the binding of human (h) PTH(1-34) to canine renal membrane in an essentially similar fashion to hPTH(1-34) or PTH-related protein (rP). In the renal membrane, neither of these peaks stimulated adenylate cyclase (AC) but rather dose-dependently inhibited AC activity stimulated by hPTH(1-34), PTH-rP(1-34) or forskolin. In rat renal cortical slices, however, both peaks could exhibit their own stimulatory effect and did not inhibit PTH or forskolin-stimulated cAMP production. It has been concluded that a factor which inhibits AC activity, probably reflecting the direct action at catalytic site, can occasionally be produced with PTH-like factor. Although PTH-like and AC-inhibiting activities were very close on reverse phase HPLC, currently the interrelation between these two activities is not clear. It may be important to be aware of the presence of such a factor in the evaluation of the bioassay data employing a broken cell preparation, which is often used to assess the PTH-like activity of tumor products.

Parathyroid hormone-related protein and transforming growth factor activities in an extract from a breast cancer associated with humoral hypercalcemia of malignancy.

The pathogeneses of hypercalcemia and hypophosphatemia which developed in a patient with metastatic invasive ductal breast carcinoma were studied. The patient had low plasma levels of immunoreactive parathyroid hormone (PTH) and 1,25(OH)2D, increased nephrogenous cyclic adenosine monophosphate (cAMP) excretion and low TmPO4/GFR, suggesting the presence of humoral PTH-like activity. The tumor extract showed activities which would stimulate bone resorption in vitro and cAMP generation in the osteogenic cell line, MC3T3 E1, and in the rat kidney cortex. In addition, the extract stimulated epidermal growth factor (EGF)-independent colony formation of the NRK 49F cells in soft agar, and inhibited the binding of EGF to A431 cells, indicating it to have transforming growth factor (TGF)-alpha activity. The extract contained appreciable amounts of immunoreactive PTH-related protein (PTH-rP) but negligible amounts of immunoreactive PTH. Thus, the PTH-like activity for stimulating cAMP generation in the bone and kidney was attributed to PTH-rP. Chromatographic analyses on reverse phase high performance liquid chromatography (HPLC) separated the PTH-rP activity from that of TGF-alpha and the bone resorbing activity in vitro was found only in the fractions of PTH-rP. It was concluded that this breast cancer produced PTH-rP as well as TGF-alpha, and the former was thought to have a major role to play in the humoral hypercalcemia of malignancy observed in this patient.

The tumor cells (FA-6) established from a pancreatic cancer associated with humoral hypercalcemia of malignancy: a simultaneous production of parathyroid hormone-like activity and transforming growth factor activity.

Human pancreatic cancer cells (FA-6) producing bone resorbing factor were established in culture. A biopsied lymphnode from a patient with pancreatic cancer associated with humoral hypercalcemia of malignancy (HHM) was transplanted to nude mice, and the cells producing high parathyroid hormone (PTH)-like activity were selected by a limited dilution from outgrowth of the xenografts of the tumor grown in nude mice. The conditioned media contained an activity to stimulate the resorption of mouse calvaria in vitro which was indomethacin-insensitive. The conditioned media had both alpha-type and beta-type transforming growth factor (TGF) activity but no interleukin-1 activity. TGF-alpha activity was co-eluted with PTH-like activity from gel-chromatography at around 15 kDa. The FA-6 cells now established are the first cells of pancreatic cancer associated with HHM producing both PTH-like and TGF-alpha activities along with bone resorbing activity.

On the activities of parathyroid hormone-like factor and transforming growth factors in extract of pancreatic cancer associated with humoral hypercalcemia of malignancy.

Extract of exocrine pancreatic cancer associated with humoral hypercalcemia of malignancy was examined for biological activities of PTH-like factor and transforming growth factor (TGFA and TGFB), both of which are possible causes of hypercalcemia. The crude extract had both PTH-like and TGF activities. On Bio Gel P-60 column chromatography, PTH-like and TGFA activities were eluted at around 10 kD, whereas TGFB activity was eluted at around void fractions, 10 kD and 6 kD. Liver extract, used as a control material, exhibited only TGFB activity at around 6 kD. CM-cellulose column chromatography of 10 kD fractions resulted in a subtle distinction between PTH-like activity and TGF activities. Further fractionation of the peak with PTH-like activity on reverse-phase high performance liquid chromatography separated PTH-like activity distinctly from TGFB activity. TGFA activity was lost through the procedure. It was concluded that the exocrine pancreatic cancer associated with hypercalcemia produced not only PTH-like activity but also TGFA and TGFB activities. Several chromatographic analyses suggested that PTH-like activity and at least TGFB activity stem from distinct molecules and that the PTH-like factor has no significant TGFB activity intrinsically.