A new radioimmunoassay for the midregion of canine parathyroid hormone.

A new radioimmunoassay for canine PTH employs a goat antiserum against native bovine and human PTHs, with either [125I]bPTH-(41-84) or [125I] [tyr43]-hPTH-(43-68) as Tracer. The assay is monospecific for the midregion (44-68) of PTH. Assay of 40-microliters aliquots allowed detection of PTH in 20 of 22 sera from normal dogs, with these normal iPTH levels inhibiting tracer binding by 19-68%. iPTH levels rose markedly after a decrease in serum calcium ion activity induced by intravenous injection of disodium EDTA; the rise could be detected at 3 min and showed two peaks, one at 3-6 min and one at 10-15 min. After parathyroidectomy, PTH immunoreactivity disappeared rapidly from serum. After nephrectomy, iPTH increased many-fold within 12 h. The assay has a similar specificity and sensitivity to our recently described midregion assay for human PTH and should prove useful in studies of normal parathyroid physiology.

Hypercalcemia after nephrectomy in the dog: role of the kidneys and parathyroid glands.

UNLABELLED: To examine the role of the kidneys and parathyroid glands in the development of hypercalcemia after bilateral nephrectomy, changes in serum calcium and iPTH were measured in dogs after bilateral nephrectomy, bilateral ureteral ligation, bilateral nephrectomy of thyroparathyroidectomized animals, or sham operation. Total calcium increased at 24 hr after nephrectomy, remained unchanged after bilateral ureteral ligation or sham surgery, and decreased after nephrectomy of thyroparathyroidectomized dogs. Ionized calcium decreased significantly at 12 hr after nephrectomy or ureteral ligation but returned to normal after 24 to 48 hr. At 72 hr ionized calcium remained normal in the nephrectomized animals but fell significantly in the ureteral ligation animals. At 12 and 24 hr, PTH was significantly higher (4.3- and 2.0-fold, respectively) in the nephrectomized group than in the ureteral ligation group. CONCLUSIONS: (1) the increase in total serum calcium after bilateral nephrectomy in the dog is not accompanied by an increase in ionized calcium; (2) intact parathyroid function is necessary for the increase in total calcium and for the maintenance of ionized calcium after nephrectomy; (3) the presence of the kidneys in the ureteral ligation model prevents the rise in total serum calcium and allows a fall in ionized calcium.

Renal papillary necrosis: an update.

The clinical and diagnostic features of renal papillary necrosis (RPN) of 27 patients were studied. Diabetes mellitus was the most frequent (56%) condition associated with RPN. Analgesic abuse, sickle hemoglobinopathy and urinary tract obstruction were present in 4 patients each; in 6 of these 12 patients these conditions were present as a coexistent disease with diabetes mellitus. There was evidence of an acute or chronic infection of the urinary tract in 18 patients, as a coexistent condition with another underlying disease that itself can cause RPN in 14 patients and as the only cause of RPN in another 4. Thus, the presence of more than one diagnostic condition which might be implicated in the causation of RPN was present in 15 patients or 55% of the cases in this series. When infection was excluded, six patients or 22% of the cases had two coexisting diseases, each of which has been implicated as a cause of RPN. This observation underlines the multifactorial nature of this entity and might explain why RPN is not encountered more frequently in each of the various primary diseases with which it has been associated. The average age of the patients at the time of diagnosis was 53 years for women and 56 years for men. Only six of the patients were younger than 40 years, and three of these had sickle hemoglobinopathy. The diagnosis of RPN was based on x-ray findings in eight patients, on the histologic examination of papillary tissue in urine in one, and on autopsy findings in the rest. Papillary necrosis was bilateral in three-fourths of the cases. The clinical picture varied. Most of the patients (67%) presented with chills and fever. Flank pain and dysuria were present in 11 patients (41%). As a rule oliguria was rare and progressive uremia was uncommon. In cases diagnosed at post-mortem, the patients had succumbed to infection or to a primary severe extrarenal disorder with the possibility of RPN having been entertained clinically in only half these cases prior to autopsy.

Seizures and dermatitis after exposure to caprolactam.

A 22-year-old man was initially seen with dermatitis, fever, and seizures after three days of occupational exposure to caprolactam, a nylon fiber precursor. A comprehensive neurological investigation showed no organic CNS abnormalities. Although caprolactam has been shown to induce convulsive disorders in experimental animals, to our knowledge, there are no reports of caprolactam-induced seizures in man. The coincidence of typical skin lesions with otherwise unexplained grand mal seizures in this strongly suggests that caprolactam was the cause.

Augmented polymorphonuclear chemiluminescence in patients with secondary hyperparathyroidism.

The effect of secondary HPT on PMN function, as assessed by CL, was studied in two groups of patients. Group 1 comprised seven patients with no clinical evidence of secondary HPT and mildly elevated levels of serum iPTH (mean 2.7 +/-0.9 microleq/ml), and group 2 had six patients with clinical and radiological evidence of secondary HPT and higher ( p < 0.001) levels of iPTH (mean 26 +/- 7 microleq/ml). PMNs from group 2 patients demonstrated 68% +/- 9 augmented CL in the presence of autologous serum. Cross-incubation studies showed that sera from group 2 patients induced augmented CL in normal PMNs. In contrast, PMNs from group 2 patients showed reduced CL in the presence of normal serum. The augmenting effect of group 2 sera did not correlate with the level of calcium, phosphorus, creatinine, or BUN in serum. After successful subtotal parathyroidectomy, evident by the decrease of serum iPTH levels, both the CL of group 2 PMNs and the ability of group 2 sera to induce augmented CL in normal PMNs decreased (p < 0.025). These results suggest that secondary HPT is directly or indirectly responsible for the altered leukocyte function in some patients with uremia, particularly those with marked elevation of iPTH.

Glomerular IgE deposits in patients with lupus nephritis.

The presence of glomerular IgE deposits (IgE+) and its prognostic significance were examined in 241 patients with various renal diseases. 24 patients (10%) had IgE+, and nephrotic syndrome was present in 22 (92%). 17 of the 24 patients with IgE+ had lupus nephritis. These patients were compared with another group of 32 patients with lupus nephritis, but without IgE deposits (IgE-). Light and electron microscopy showed more severe pathological changes in those with IgE+ than in patients who were IgE-. The number of patients who displayed deterioration in renal function was greater in the former group than in the latter (70 vs. 31%). Our results show that (1) nephrotic syndrome is very common among patients with IgE+; (2) the incidence of IgE deposits in lupus nephritis patients is high (35%) and the incidence of lupus nephritis among patients with IgE deposits is 71%, and (3) the presence of IgE deposits in patients with lupus nephritis may carry a bad prognosis. It is suggested that immunofluorescent studies of renal biopsies should include the evaluation of IgE deposition.

The effect of parathyroid hormone on the esophageal smooth muscle of the opossum.

The effect of parathyroid hormone on the gastrointestinal motility was studied in vitro. Isolated circular smooth muscle of the opossum esophagus were stimulated by electrical field stimulation in the absence and the presence of increasing concentration of PTH. The addition of 0.1-1.0 U./ml. of PTH to the bath resulted in 21-93% increases in the amplitude of the off response of the circular strips. Complete blockade of the neural transmission with tetrodotoxin abolished the effect of PTH. Atropine (10(-6) M) did not block the augmentatory effect of PTH on the off response. In conclusion, PTH has augmentatory effect on the off response of circulatory smooth muscle of the opossum esophagus. This effect is presumably related to the cryptogenic nerves responsible for the off response. The clinical significance of this effect is yet to be studied.