Cis-platinum treatment for malignancy-associated humoral hypercalcemia in an athymic mouse model

Summary We have established a model for malignancy-associated humoral hypercalcemia (MAHH) in athymic mice, utilizing a human squamous cell lung carcinoma. In the present studies, we evaluated cis-platinum (DDP), a cytotoxic agent known to produce hypomagnesemia, and occasionally hypocalcemia, in the treatment of MAHH. Upon development of significant hypercalcemia, defined as serum calcium (Ca)⩾11.5 mg/dl, tumor-bearing mice received either normal saline (NS) alone (1.5 ml/day, i.p.), or NS+DDP. The DDP was given as a single dose of 6 μg/g body weight i.p. Serum Ca was determined on day 6 in surviving mice (6 of 10 survived in the NS-alone group; 7 of 10 survived in the NS+DDP group). Serum Ca (mean±SE) decreased from 14.3±0.46 to a nadir of 12.7±0.33 mg/dl in the NS-alone group, and from 13.5±0.46 to a nadir of 10.4±0.48 mg/dl in the NS+DDP group. Nadir serum Ca levels were significantly lower in the NS+DDP group (P=0.003). Three of 7 surviving NS+DDP mice achieved normocalcemia, whereas none of the NS-alone animals became normocalcemic. Tumor volumes increased in all animals. There was no change in the serum Ca in 5 tumor-free mice treated with NS+DDP. There were no significant differences in serum magnesium levels among groups of control mice, tumor-free mice treated with NS+DDP, tumor-bearing mice treated with NS+DDP, and tumor-bearing mice treated with NS-alone. We conclude that DDP is an effective agent for the treatment of MAHH, through a mechanism distinct from its antitumor cytotoxic effect and its potential to produce hypomagnesemia.     

Effect of salmon calcitonin and etidronate on hypercalcemia of malignancy

Summary Hypercalcemia of malignancy is a commonly encountered serious clinical problem that often requires aggressive therapy. In order to combine the rapid hypocalcemic effects of calcitonin with the more delayed effect of a bisphosphonate, we administered etidronate, 7.5 mg/kg/day intravenously and salmon calcitonin, 100 IU subcutaneously, every 12 hours for 3 days in 9 patients with hypercalcemia associated with malignancy. The mean serum calcium concentration fell from 3.33±0.1 mmol/liter (mean±SEM) to 2.88±0.1 mmol/liter within 24 hours (P<0.001). All patients had a fall in the serum calcium concentration of >0.5 mmol/liter and it returned to normal in 7 of the 9 patients. We conclude that the combination of salmon calcitonin with etidronate more effectively lowers the serum calcium concentration in patients with hypercalcemia of malignancy then the use of either agent alone.     

The effects of dichloromethylene diphosphonate on hypercalcemia and other parameters of the humoral hypercalcemia of malignancy in the rat leydig cell tumor

Summary There is a high frequency of Leydig cell tumors associated with hypercalcemia in the aged Fischer 344 rat. We studied a transplantable tumor cell line (Rice D-6) which is associated with hypercalcemia, hypercalciuria, hypophosphatemia, renal phosphate wasting, increased urinary cyclic adenosine monophosphate (AMP) excretion, absence of bone metastases, increased osteoclastic bone resorption, and suppressed immunoreactive parathyroid hormone (iPTH) concentrations. We examined the ability of dichloromethylene diphosphonate (Cl₂MDP) to lower serum calcium and decrease the parameters of increased bone resorption. We used this drug also as a pharmacologic tool to determine the relationship of hypercalcemia and increased bone resorption to the abnormalities in renal tubular function associated with the humoral hypercalcemia of malignancy. Daily administration of Cl₂MDP before development of hypercalcemia, in doses from 2.5–40 mg/kg body weight subcutaneously, delayed and suppressed both the hypercalcemia and hypercalciuria. There was an increase in bone mass and decrease in both osteoclast number and activity compared with bones from untreated tumor-bearing animals. The urinary hydroxyproline excretion in treated animals declined towards the normal range. There were no significant effects on serum phosphorus, urine phosphorus, or urine cyclic AMP excretion. These data suggest that Cl₂MDP reverses the increased bone resorption that occurs in the humoral hypercalcemia of malignancy, and confirms that diphosphonates are effective agents in the prevention and treatment of increased bone resorption associated with malignant disease. They also suggest that renal phosphate wasting and increased urinary cyclic AMP excretion are not directly related to the hypercalcemia.     

Canine lymphosarcoma: A model for study of the hypercalcemia of cancer

Summary Lymphosarcoma of domestic dogs is often accompanied by hypercalcemia. We have carried out studies to determine the usefulness of this common canine neoplasm as a model for paraneoplastic hypercalcemia. The study population consisted of 27 healthy control dogs, 13 with hypercalcemic lymphosarcoma, and 28 normocalcemic dogs with lymphosarcoma. Studies included measurement of circulating calcium, phosphorus, creatinine, immunoreactive parathyroid hormone (iPTH) and prostaglandin E₂ (iPGE₂) concentrations, and determination of in vitro bone-resorbing activity in supernatant culture media from normal and neoplastic lymphoid tissue. Hypercalcemia was severe in the affected group (mean ± SE, 14.9±0.5 mg/dl, normals 10.1±0.1 mg/dl) and associated with decreased renal function (serum creatinine 2.0±0.4 mg/dl, normal 0.8±0.1 mg/dl,P<0.001). Radiographs and autopsies showed no bone destruction. Despite renal insufficiency, hypercalcemic dogs had subnormal serum iPTH concentrations (12±1 ngEq/ml, normals 37±6 ngEq/ml,P<0.05). Creatinine and iPTH were normal in the normocalcemic tumor-bearing dogs. When antitumor therapy lowered serum calcium to normal or below in 5 hypercalcemic dogs, iPTH rose markedly in all while renal function improved. Plasma iPGE₂ levels did not differ among the groups, nor did high-dose oral aspirin or indomethacin treatment lower elevated serum calcium (two dogs). Culture media from normal lymphoid tissue and control culture media had no effect on release of⁴⁵Ca from prelabeled fetal mouse forelimb bones, but media from tumor tissue increased⁴⁵Ca release. However, correlation of serum calcium with in vitro bone-resorbing activity was poor. We conclude that (a) the hypercalcemia of canine lymphosarcoma is mediated not by bone metastases or “ectopic” secretion of PTH, but by other bone-resorbing factors secreted by the tumors; and (b) canine lymphosarcoma may be a valuable experimental model for study of some human paraneoplastic hypercalcemias. Present address: Mackintosh Veterinary Clinic, 401 South First Street, Yakima, WA 98907, USA.     

甲状旁腺素相关肽诱导的局部骨吸收及高钙血症动物模型特点

目的研究甲状旁腺素相关肽(PTHrP)诱导的局部骨吸收及高钙血症动物模型特点。方法于小鼠颅骨注射PTHrP9μg/10μL,每日2次。注射前、注射1d、注射3d、注射5d的不同时间内检测血钙水平;注射3d及5d的不同时间内取材,行X线检查和组织学检查。结果注射PTHrP3d后出现高钙血症(>2.0mmol/L),维持3～6h,10h后下降犤(1.50±0.10)mmol/L犦,正常水平为(1.11±0.09)mmol/L;注射PTHrP5d后3h再次上升犤(2.05±0.34)mmol/L犦,10h后下降犤(1.50±0.16)mmol/L犦。骨吸收在注射3d后的24h明显犤(6.839±1.974)mm2犦,注射5d后更为明显犤(22.751±7.090)mm2犦。结论PTHrP诱导的局部骨吸收动物模型最短取材时间以注射3d后的24h为宜,血钙水平的变化呈波动性变化。     

Factors predicting the acute effect of pamidronate on serum calcium in hypercalcemia of malignancy

Summary In this study we retrospectively reviewed results of the first 9 days of treatment with pamidronate at doses of 30 mg (n=13), 45 mg (n=9), and 90 mg (n=13) in an attempt to see what factors influenced the response of serum calcium to pamidronate.The nadir of serum calcium obtained post treatment was correlated with pretreatment levels of nephrogenous cyclic adenosine monophosphate (NcAMP), the renal tubular threshold for phosphate reabsorption (TmPO4), and the renal tubular threshold for calcium reabsorption (TmCa). Using the post treatment serum calcium levels, patients were divided into good and poor responders depending on whether a normal serum calcium was obtained.Pretreatment NcAMP was significantly correlated with the magnitude of the response of serum calcium (r=0.45, P=0.0001). Pretreatment NcAMP was significantly higher in the poor responders (mean±SEM): 65.0±9.4 nmol/liter GF (poor responders) versus 29.6±6.3 (good responders), P=0.004. NcAMP as a predictor of the acute response of serum calcium showed a sensitivity of 93% and a specificity of 72%. Pretreatment TmPO4 was negatively correlated with the serum calcium response post treatment (r=-0.41, P=0.003). However, though TmPO4 tended to be lower in the poor responders, this was not statistically significant [0.65 mmol/liter GF±0.09 (poor responders) versus 0.76 mmol/liter GF±0.06 (good responders)]. As a predictor of the acute response of serum calcium, TmPO4 was less good with a sensitivity of 70% and specificity of 58%. No significant correlation was present between TmCa and the serum calcium response. A significant negative correlation was evident between NcAMP and TmPO4 (r=-0.35, P=0.003), however, no significant correlation was evident between NcAMP and TmCa or TmPO4 and TmCa.These results suggest that in a hypercalcemic patient where evidence exists for the presence in circulation of a factor with PTH-like activity (i.e., NcAMP is elevated or TmPO4 is low) the response of serum calcium to pamidronate is less good. NcAMP would appear to be a useful predictor of the response of serum calcium, whereas TmPO4 is less discriminating.     

Nasal human calcitonin for tumor-induced hypercalcemia

Summary We treated four hypercalcemic cancer patients by nasal hCT, 3×2 mg daily, which has been reported to be active in Paget's disease at lower doses. Only one patient became normocalcemic and mean (± SEM) calcium levels fell from 11.6±0.2 mg/dl before therapy to 10.7±0.6 mg/dl 2–3 days after starting hCT. The tolerance was excellent but, because of insufficient efficacy, we do not recommend this form of therapy for cancer hypercalcemia.     

Genetic hypercalcemia

A genetic disorder should be suspected in patients with hypercalcemia, notably those who are young; have family members with hypercalcemia; or have had a tumor of the endocrine pancreas, thyroid, pituitary, adrenal gland, or jaw bone. All forms of hypercalcemia should be interpreted according to the serum level of parathyroid hormone (PTH). Genetic forms are thus classified as related or unrelated to a parathyroid gland disorder. When the PTH level is elevated or is not depressed despite the hypercalcemia, findings that suggest family history of hypercalcemia due to a genetic cause include syndromic manifestations in the patient or family members, parathyroid cancer (either suspected before surgery or confirmed during parathyroidectomy), multiple or recurrent parathyroid tumors, a family history of primary hyperparathyroidism, and the onset of primary hyperthyroidism before 50 years of age. In patients with moderate hypercalcemia, a normal PTH level, and relative hypocalciuria, the first hypothesis is a mutation in the calcium-sensing receptor gene, which is often difficult to distinguish from primary hyperparathyroidism, particularly when there is no known family history of hyperparathyroidism, as is often the case. A low PTH level suggests non-parathyroid hypercalcemia due to a genetic defect in patients with no evidence of other conditions associated with hypercalcemia and low PTH levels and in those whose calcitriol levels are elevated or normal (instead of depressed as expected when PTH is elevated). Patients with hypercalciuria but no evidence of conditions such as granulomatous diseases should be evaluated for increased vitamin D sensitivity due to a CYP 4A1 mutation. Other very rare causes include hypophosphatasia due to ALPL mutations, which is characterized by a low alkaline phosphatase level; and renal phosphate wasting due to an NPT2A mutation, in which serum phosphate levels are low. A thorough analysis of the clinical and laboratory data can point toward a genetic disorder in patients with hypercalcemia. The diagnosis is then confirmed by obtaining genetic tests tailored to the clinical and laboratory test abnormalities. The current development of diagnostic genetic testing is shedding new light on the phenotypes, thereby improving their management.     

Osteoclastogenesis inhibitory factor exhibits hypocalcemic effects in normal mice and in hypercalcemic nude mice carrying tumors associated with humoral hypercalcemia of malignancy

Osteoclastogenesis inhibitory factor (OCIF) is a novel secreted protein that inhibits osteoclastogenesis both in vitro and in vivo. In this study, we examined the effects of OCIF on serum calcium (Ca) concentrations in normal mice and in hypercalcemic nude mice carrying tumors associated with humoral hypercalcemia of malignancy. In normal mice, a single intraperitoneal injection of OCIF reduced serum Ca levels in a dose-dependent manner. Significant decrease in serum Ca (by 1.6 ± 0.3 mg/dL, n = 5) was observed 2 h after the injection of OCIF at 20 mg/kg and the hypocalcemic effect continued for up to 12 h. Serum phosphate (Pi) concentrations also decreased in response to OCIF. Urinary excretion of Ca, Pi, and creatinine did not change significantly after injection of OCIF or vehicle. In hypercalcemic, tumor-bearing nude mice, a single intraperitoneal injection of OCIF at 20 mg/kg resulted in a dramatic decrease in serum Ca (maximal decrease 2.8 ± 0.37 mg/dL, n = 11), which continued for up to 24 h. The results suggest that OCIF decreased serum Ca through its inhibitory effect on bone resorption. Furthermore, it is suggested that OCIF has therapeutic potential for the treatment of hypercalcemic conditions such as malignancy-associated hypercalcemia.     

A hypercalcemic nude rat model that completely mimics human syndrome of humoral hypercalcemia of malignancy

Summary Tumors causing humoral hypercalcemia of malignancy (HHM) were implanted to athymic nude rats. In one of these rat models transplanted with uterine cancer (UCC), a complete reproduction of human HHM syndrome was achieved: hypercalcemia, hypophosphatemia with increased urinary phosphate and cyclic AMP excretion, and suppressed serum 1,25-dihydroxy-vitamin D (1,25(OH)₂D) level. In another hypercalcemic nude rat model implanted with oral cavity cancer (OCC), all the features were similar except for markedly elevated serum 1,25(OH)₂D. Hypercalcemia disappeared by surgical removal of the tumors in both models, confirming the humoral mechanisms for causing these features. Furthermore, in UCC tumor-bearing rats, hypophosphatemia, increased renal phosphate excretion, and reduced serum 1,25(OH)₂D concentration were already present when these rats were only marginally hypercalcemic. These results raise the possibility that the changes in renal tubular phosphate handling and vitamin D metabolism in HHM are not secondary to hypercalcemia but are due to direct effects of the humoral factor(s) that cause this syndrome. Extracts of both tumors exhibited stimulation of cyclic AMP production in osteoblastlike cells, UMR 106, which could be almost completely inhibited by parathyroid hormone (PTH) antagonist, human PTH(3–34). By comparing the nature and characteristics of humoral factor(s) from UCC and OCC models, mechanisms responsible for causing these abnormalities can be explored. Thus, these nude rat models can be useful for elucidating the underlying mechanism of the development of HHM.     

Congenital mesoblastic nephroma associated with polyhydramnios and hypercalcemia

Congenital mesoblastic nephroma (CMN) can present with atypical clinical and imaging findings. A premature male neonate was born to an 18-year-old woman after 33 weeks’ gestation, which was complicated by polyhydramnios and placenta abruptio. A right abdominal mass was diagnosed antenatally. From the 1st day of life, the newborn had hypercalcemia with initially normal parathormone levels and polyuria for the first hours of life and normal urine output afterwards. Ultrasonographic study and magnetic resonance imaging of the abdomen showed at the upper pole of the right kidney a heterogeneous, solid, poorly defined mass, partially surrounded by a subcapsular fluid collection mimicking malignant rhabdoid tumor of the kidney. Surgical resection revealed a CMN of mixed, classic, and in areas, cellular type. One year after the resection, the patient is asymptomatic and normocalcemic. In conclusion, CMN may present with atypical clinical and imaging findings, necessitating an extensive work-up in order to exclude highly malignant renal tumors of the neonatal period. Received: 12 December 2000 / Revised: 1 May 2001 / Accepted: 9 October 2001     

重症胰腺炎动物模型制作及发病机理的研究

为探讨胰腺炎的发病机理，作者采用大鼠（ｎ＝５８只）十二指肠结扎法和犬（ｎ＝４６条）胰管内注射自身胆汁法制作重症胰腺炎的动物模型。该模型接近人类急性胰腺炎的发病因素，方法可靠，操作简便，费用便宜。前者适用于小动物实验，后者宜于大动物实验。作者认为胰管内压力增高和微生物是急性胰腺炎的重要条件；胰酶激活始动时间早在胰管内胆汁和肠液的反流后，胰酶激活的主要部位在腺泡细胞。     

A novel animal model of gastrointestinal obstruction for the development of stent

Background

The need for newer gastrointestinal (GI) stents has been continuously raised. Newly developed stents are generally tested for physical properties in vitro and directly introduced to clinical practice because there is no reliable animal model of GI obstruction. The aim of this study was to establish an animal model both that can represent obstruction of the GI tract and be used to develop new stents.

Material and methods

Surgical obstruction of the descending colon by wrapping with a nonabsorbable synthetic mesh and rubber bands was made in 17 healthy mongrel dogs. Four days later, a covered self-expanding metallic stent was placed for the obstructed segment in each dog under fluoroscopic guidance. Patency and migration of the inserted stents were evaluated clinically on a daily basis and fluoroscopically on a weekly basis. After sacrifice of the dogs, the degree and extent of residual colonic obstruction were assessed fluoroscopically. The specimen of the colonic obstructed segment was examined microscopically.

Results

In all 17 mongrel dogs, segmental obstruction in the descending colon was successfully created and confirmed with fluoroscopic examination using a contrast medium. The percentage of luminal narrowing ranged from 99%–100%. Stent placement was technically successful in all 17 dogs. During the follow-up period, stent migration occurred in 12 dogs and indwelling time of a stent ranged from 0–95 d (mean 29.2 ± 38.8 d). On postmortem pathologic examination, it was found that fibrosis had newly formed outside the colonic longitudinal muscle layer in all dogs.

Conclusions

Our canine colonic obstruction model is the first animal model that can be feasible for developing a new design of stent and provide in vivo data on complications, particularly stent migration.     

Treatment of severe hypercalcemia with peritoneal dialysis in an infant with end-stage renal disease

Recurrent and unusually severe hypercalcemia was observed in an infant undergoing continuous cyling peritoneal dialysis and receiving oral calcitriol and calcium carbonate. Rapid correction was achieved with peritoneal dialysis using a calcium-free dialysis solution.     

Familial hypercalcemia and hypercalciuria: no mutations in the Ca2+-sensing receptor gene

A 6-year-old boy presented with persistent hypercalcemia, hypercalciuria and nephrocalcinosis from early infancy. His 40-year-old father also had hypercalcemia and hypercalciuria. In both individuals serum values of intact parathyroid hormone (PTH) were repeatedly normal. Although these findings suggest a functional abnormality of the calcium-sensing receptor (CaR), no mutations in coding regions of the CaR gene could be demonstrated. Received: 2 January 2001 / Revised: 2 May 2001 / Accepted: 2 May 2001     

Mechanism of induction of hypercalcemia and hyperphosphatemia by lead acetate in the rat

Summary The present study is an investigation of the mechanism of hypercalcemia and hyperphosphatemia induced by the intravenous injection of lead acetate (Pb-Ac). A total of 118 male rats were injected with 30 mg/kg of Pb-Ac, or with 16.5 mg/kg of sodium acetate as the control. The levels of serum calcium, phosphorus and lead were then determined at various time periods after the injections. Serum calcium and phosphorus levels increased with time after Pb-Ac injection and the maximum values of calcium (17 mg%) were found after 1 h and of phosphorus (13.5 mg%) after 30 min. Both calcium and phosphorus levels reverted to the normal range after 12 h. The maximum net rates of increase of calcium and phosphorus were found immediately after Pb-Ac injection. At that time, deposition of lead at the calcifying sites of bone and incisor dentin was demonstrated by a histochemical examination. In other experiments the changes in the calcium and phosphorus contents in the medium after shaking bone powder in serum with Pb-Ac in an in vitro system were studied. It was confirmed that the calcium and phosphorus were displaced from the bone mineral, the extent of the displacement being correlated with the concentration of the Pb-Ac added to the medium, and that these displacements were very rapid reactions. These results suggest that hypercalcemia and hyperphosphatemia following Pb-Ac injection results from a direct action of lead on the bone mineral.     

Successful palliation of hypercalcemia secondary to metastatic parathyroid cancer: an unusual indication for hepatic resection

Primary carcinoma of the parathyroid gland is a rare disease. It is often diagnosed after recurrence of hyperparathyroidism following resection for presumed adenomatous disease. Local and distant recurrence is high and aggressive resection is advocated. Patients with parathyroid cancer are frequently plagued by severe hypercalcemia, which is often refractory to medical therapy. Herein we describe the case of a patient with metastatic parathyroid cancer localized to the liver. The patient was treated with a palliative hepatic resection for the management of persistent and refractory hypercalcemia. Intraoperative parathyroid hormone levels were utilized as an adjunct to determine successful metastatectomy. Our case highlights the importance of an aggressive approach to patients with metastatic parathyroid cancer, as well as the utility of intraoperative parathyroid hormone levels to confirm successful extirpation of disease. the authors declare no conflicts of interest     

A suitable animal model for laparoscopic hepatic resection training

Background There is a growing interest in using laparoscopy for hepatic resection. However, structured training is lacking in part because of the lack of an ideal animal training model. We sought to identify an animal model whose liver anatomy significantly resembled that of the human liver and to assess the feasibility of learning laparoscopic hepatic inflow and outflow dissection and parenchyma transection on this model. Methods The inflow and outflow structures of the sheep liver were demonstrated via surgical dissection and contrast studies. Laparoscopic left major hepatic resections were performed. Results The portal hepatis of all 12 sheep (8 for anatomic study and 4 for laparoscopic hepatic resection) resembled that of human livers. The portal vein (PV) was located posteriorly; the common hepatic artery (CHA) and the common bile duct (CBD) were located anterior medially and anterior laterally with respect to the portal hepatis. The main PV bifurcated into a short right and a long left PV. The extrahepatic right PV then bifurcated into right posterior and anterior sectoral PV. The CBD and CHA bifurcated into left and right systems. The cystic duct originated from the right hepatic duct. The cystic artery originated from the right HA in 11/12 animals. The left hepatic vein drained directly into the inferior vena cava (IVC). The middle and the right hepatic veins formed a short common channel before entering the IVC. Multiple venous tributaries drained directly into IVC. Familiarity with sheep liver anatomy allowed laparoscopic left hepatic lobe (left medial and lateral segments) resection to be performed with accuracy and preservation of the middle hepatic vein. Conclusions The surgical anatomy of sheep liver resembled that of human liver. Laparoscopic major hepatic resection can be performed with accuracy using this information. Sheep is therefore an ideal animal model for advanced surgical training in laparoscopic hepatic resection.     

尿道下裂兔动物模型的建立

目的为尿道下裂的病因学研究提供实验依据。方法使用非那雄胺诱导建立兔尿道下裂动物模型。孕兔40只,随机分为5组。孕19天开始给予非那雄胺口服,10mg·kg-1·d-1,各组用药时间分别为0(A)、4(B)、5(C)、6(D)、7d(E),其中A组为对照组。出生后5周观察雄性幼兔有无尿道下裂;10周观察有无隐睾,分辨尿道下裂严重程度;解剖观察睾丸发育情况。结果A~E组子代尿道下裂发生率分别为0、22.2%、95.5%、85.2%、100.0%,根据外观将尿道下裂的严重程度分为3级。A~E组隐睾发生率分别为0、0、36.4%、40.7%、73.3%。结论应用非那雄胺可以诱导出稳定的雄性幼兔先天性尿道下裂模型。