[Pressure load of the aneurysm sac after endovascular treatment of aortic aneurysm]. / Druckentlastung im Aneurysmasack nach endovaskulärer Therapie von Aortenaneurysmen.

PURPOSE: Stent grafting of aortic aneurysms should result in relief of pressure within the excluded aneurysmal sac, however confirming data are not available. This study evaluates the intra-extraluminal pressure translation and translation of maximum pressure increase (dp/dtmax) into the excluded aneurysmal sac after endovascular treatment of experimental aortic aneurysms. MATERIALS AND METHODS: Experimental autologous aneurysms were created surgically using a patch from the sheath of the rectus abdominis muscle in 12 mongrel dogs. After 12 weeks reconvalescence, endovascular treatment was performed viafemoral access using dacron-covered nitinol stents. Spiral CT and angiography were performed at one week and six weeks follow-up and 6 animals each. Laparotomy was performed for hemodynamic measurements. A manometer-tipped catheter was introduced into the excluded aneurysmal sac. A second manometer-tipped catheter was placed intraluminally within the stent graft. Pressure curves and their first derivative dp/dt were simultaneously recorded to calculate the intra-extraluminal transmembraneous pressure transmission. RESULTS: At one week follow-up systolic blood pressure and mean blood pressure were significantly reduced by factors of 0.60 +/- 0.17 (p < 0.01) and 0.78 +/- 0.3 (p < 0.05), respectively in the excluded aneurysm sac. The maximal pressure increase, dp/dt max, was considerably reduced by a factor of 0.06 +/- 0.05 (p < 0.01). However, the diastolic blood pressure was not significantly changed. There were no hemodynamic differences between one and six weeks follow-up. CONCLUSION: In experimental aortic aneurysms, endovascular treatment with stent grafts significantly reduces the systolic peak pressure and dp/dt max in the excluded aneurysmal sac, and thereby significantly reduces the wall stress in the diseased aneurysm wall. Despite complete exclusion of the aneurysm, a considerable pressure load remains in the excluded aneurysmal sac.

Calcium concentration in the CAPD dialysate: what is optimal and is there a need to individualize?

OBJECTIVE: To evaluate risk/benefit of various continuous ambulatory peritoneal dialysis (CAPD) dialysate calcium concentrations. DATA SOURCES: A review of the literature on the effects of various CAPD dialysate Ca concentrations on plasma Ca, plasma phosphate, plasma parathyroid hormone (PTH), doses of calcium carbonate, doses of vitamin D analogs, and requirements of aluminum-containing phosphate binders. STUDY SELECTION: Eleven studies of nonselected CAPD patients, and 13 studies of CAPD patients with hypercalcemia were reviewed. RESULTS: In nonselected CAPD patients, treatment with a reduced dialysate Ca concentration (1.00, 1.25, or 1.35 mmol/L) improved the tolerance to calcium carbonate and/or vitamin D metabolites and reduced the need for Al-containing phosphate binders. When using dialysate Ca 1.25 or 1.35 mmol/L, the initial decrease of plasma Ca and increase of PTH could easily be reversed with an immediate adjustment of the treatment. After 3 months, stable plasma Ca and PTH levels could be maintained using only monthly investigations. In patients with hypercalcemia and elevated PTH levels, treatment with dialysate Ca concentrations below 1.25 mmol/L implied a considerable risk for the progression of secondary hyperparathyroidism. When hypercalcemia was present in combination with suppressed PTH levels, a controlled increase of PTH could be obtained with a temporary discontinuation of vitamin D and/or a reduction of calcium carbonate treatment in combination with a dialysate Ca concentration of 1.25 or 1.35 mmol/L. CONCLUSION: Most CAPD patients can be treated effectively and safely with a reduced dialysate Ca concentration of 1.35 or 1.25 mmol/L. Treatment with dialysate Ca concentrations below 1.25 mmol/L should not be used. A small fraction of patients with persistent hypocalcemia need treatment with high dialysate Ca, such as 1.75 mmol/L.

A prospective, randomized multicenter study comparing APD and CAPD treatment.

OBJECTIVE: The goals for maintenance dialysis treatment are to improve patient survival, reduce patient morbidity, and improve patient quality of life. This is the first randomized prospective study comparing automated peritoneal dialysis (APD) and continuous ambulatory peritoneal dialysis (CAPD) treatment with respect to quality of life and clinical outcomes in relation to therapy costs. DESIGN: A prospective, randomized multicenter study. SETTING: Three Danish CAPD units. PATIENTS: Thirty-four adequately dialyzed patients with high or high-average peritoneal transport characteristics were included in the study.Twenty-five patients completed the study. INTERVENTIONS: After randomization, 17 patients were allocated to APD treatment and 17 patients to CAPD treatment for a period of 6 months. Medical and biochemical parameters were evaluated at monthly controls in the CAPD units. Quality-of-life parameters were assessed at baseline and after 6 months by the self-administered short-form SF-36 generic health survey questionnaire supplemented with disease- and treatment-specific questions. Therapy costs were compared by evaluating dialysis-related expenses. MAIN OUTCOME MEASURES: Quality-of-life parameters, dialysis-related complications, dialysis-related expenses. RESULTS: The quality-of-life studies showed that significantly more time for work, family, and social activities was available to patients on APD compared to those on CAPD (p < 0.001). Although the difference was not significant, there was a tendency for less physical and emotional discomfort caused by dialysis fluid in the APD group. Sleep problems, on the other hand, tended to be more marked in the APD group. Any positive effect of APD compared to CAPD on dialysis-related hospital days or complication rates could not be confirmed. With larger patient samples, it is possible, however, that a significant difference might have been achieved. The running costs for APD treatment were US $75 per day and for CAPD treatment US $61 per day. CONCLUSION: If APD treatment can help to keep selected patients vocationally or socially active, paying the extra cost seems reasonable.

[Stage I and II Hodgkin's disease with enlarged mediastinum in adults. Apropos of 24 cases]. / Maladie de Hodgkin stade I et II à gros médiastin de l'adulte. A propos de 24 cas.

We have reported a retrospective study on 24 cases of supra-diaphragmatic Hodgkin's disease Stage I and II, with massive mediastinal invasion, followed from January 1981 to October 1986 and treated first with chemotherapy and then supra-diaphragmatic mantle type radiotherapy up to a dose of 40 Gy in 20 sessions and over 26 days; inverted irradiation was given to the aorto-lumbar region and the spleen up to a dose of 30 Gy in 15 sessions over 19 days. Supplementary irradiation to the superior mediastinum on average 10 Gy in five sessions over five days was given in two cases and five Gy in three sessions over three days in four cases. After initial chemotherapy there appeared to be a complete remission in 29% (7 out of 24), there was a partial remission in 71% (17 out of 24), of which one gave a 25% response, two a 50% response and 14 gave a response of greater than 80%. After radiotherapy the remission rate appeared complete in 96% (23 out of 24). The overall survival was 90% (19 out of 21) with a mean follow up of 45 months (range 8-78 months) with a complete remission level of 85.5% (18 out of 21). For the 13 cases followed for five years the overall survival level and the level of survival in complete remission was 84.5% (11 out of 13) and 77% (10 out of 13) respectively. We have seen symptomatic post radiotherapy pneumonia. The association of chemo and radiotherapy in this limited series of patients has enabled us to obtain a satisfying duration of remission.(ABSTRACT TRUNCATED AT 250 WORDS)

[Plasmapheresis as life-saving treatment in acute hepatic failure]. / Plasmaferese som livsbevarende behandling før levertransplantation ved akut leversvigt.

Emergency liver transplantation is the treatment of choice in acute liver failure without signs of spontaneous regeneration. However, many patients rapidly contract irreversible neurological complications before transplantation can be performed. We used high-volume plasmapheresis to increase the time span to obtain a donor liver. Four patients with acute liver failure of unknown cause and a galactose elimination capacity indicative of a virtually extinct liver function were assigned maximum priority for liver transplantation. Plasmapheresis were performed daily until transplantation. Each time 8-10 liters of patient plasma were replaced with an equal volume of fresh donor plasma. There were no major complications. None of the patients developed irreversible neurological complications for 48-144 h at which time liver transplantation was performed. High volume plasmapheresis increases the time to obtain a donor liver for emergency liver transplantation and optimizes the condition for the surgical procedure.

Effects of excess PTH on nonclassical target organs.

The classical target organs for parathyroid hormone (PTH) are the bone and kidneys. In uremia, however, numerous studies have shown that PTH may also affect the function of a number of nonclassical organs and tissues besides the bone and kidney, including the brain, heart, smooth muscles, lungs, erythrocytes, lymphocytes, pancreas, adrenal glands, and testes. Most of these effects do not apply to the generally accepted actions or normal regulatory mechanisms of PTH. Thus, the potential role of PTH as one of the possibly many toxins in uremia is of current interest. The molecular basis for the actions of elevated PTH levels on various nonrenal and nonskeletal organs or tissues might be mediated via the widespread distribution of the classical PTH/PTH-related peptide (PTHrP) receptors and via the novel PTH2 receptors. The present survey deals with an evaluation of the nonrenal and nonskeletal effects of excess PTH in uremia, taking into consideration the presently available information on the organ-specific expression of the classical and novel PTH receptors, and of the expression and function of PTHrP.

High-normal calcium (1.35 mmol/l) dialysate in patients on CAPD: efficient and safe long-term control of plasma calcium, phosphate, and parathyroid hormone.

AIM: The aim of the present study was to examine the long-term efficacy and safety of treatment with a high-normal calcium dialysate with a calcium concentration of 1.35 mmol/l in patients on CAPD. This dialysate calcium concentration is close to the high-normal plasma ionized calcium level aimed at in dialysis patients in order to suppress the parathyroid hormone secretion. The end-points of the study were (1) plasma ionized calcium (iCa) and phosphate (P) levels, (2) plasma intact parathyroid hormone (PTH) levels, (3) doses of calcium carbonate and alfacalcidol, (4) requirements of Al-containing phosphate binders, and (5) bone mineral density (BMD). RESULTS: Thirty-seven non-selected patients on CAPD treatment were followed for an average of 10 months after switching from a dialysate Ca of 1.75 to 1.35 mmol/l. After 1 week, a significant decrease of mean iCa from 1.26 +/- 0.01 to 1.23 +/- 0.01 mmol/l (P < 0.05) and an increase of median PTH from 80 to 135 pg/ml (P < 0.01) were seen. From the 2nd week and onwards, however, basal levels of iCa and PTH were restored and remained stable. mean plasma iCa was kept within 1.23-1.31 mmol/l; mean plasma P below 1.65 mmol/l and median PTH within 52-135 pg/ml. Episodes of hypercalcaemia were few (1.2 cases of plasma iCa > 1.45 mmol/l per 100 treatment weeks), and the need for Al-containing P binders low with only five patients requring this treatment for isolated and four patients for repeated episodes of hyperphosphataemia or hypercalcaemia. After switching from a dialysate Ca of 1.75 to 1.35 mmol/l, the doses of calcium carbonate and alfacalcidol could be significantly increased. Furthermore, using the dialysate Ca of 1.35 mmol/l made it possible to induce a controlled increase of PTH levels to 80-100 pg/ml by a temporarily discontinuation of alfacalcidol and/or a reduction of calcium carbonate dosage in the patients where PTH had become suppressed to levels below the upper normal limit. The intention of the treatment was to maintain PTH levels within 1.5-2.5 times the upper normal limit for non-uraemic patients. Pre-study BMD of the vertebral bodies L2-L4 and of the femoral neck were normal and not significantly different from post-study measurements. CONCLUSION: The present study demonstrated that when using a high-normal dialysate Ca concentration of 1.35 mmol/l in non-selected patients on CAPD treatment, high-normal plasma iCa and near-normal plasma P levels could be readily achieved with a minimal risk of incidental hypercalcaemia despite use of calcium carbonate as the main P binder. As a consequence of the tight Ca and P regulation, minimal doses of alfacalcidol were required to keep PTH within acceptable limits. We recommend this dialysate Ca concentration as a first-choice therapy for the majority of patients starting on CAPD treatment.

Risk/benefit in prophylaxis and treatment of secondary hyperparathyroidism. A comparison of two low calcium peritoneal dialysis fluids.

OBJECTIVE: A comparison of (i) levels of plasma ionized calcium (Ca), phosphate (P) and iPTH, (ii) risk of hypercalcaemia and (iii) need for Al-containing P binders, in patients on CAPD treated with calcium carbonate as the main P binder and twice weekly oral doses of alfacalcidol for control of secondary hyperparathyroidism during a 1 year follow-up after switching from a dialysis fluid with a Ca concentration of 1.75 mmol/l to 1.25 mmol/l (n = 39) or 1.35 mmol/l (n = 37). RESULTS: In both groups, a significant initial increase of iPTH was seen. However, iPTH was again suppressed to baseline levels after 2-6 weeks of treatment. No statistically significant difference was observed between the two groups. In both groups median PTH levels were kept below 2.5 times the upper normal limit for non-uraemic patients; median P concentrations below 1.80 mmol/l and median iCa levels within 1.25-1.30 mmol/l. The incidence of hypercalcaemia was low and did not differ between the two groups (1.04 vs 1.20 cases of plasma iCa > 1.45 mmol/l per 100 treatment weeks). The proportion of patients requiring treatment with Al-containing P binders was unchanged from the start to the end of the study period, but significantly greater in the group dialysed with a Ca concentration of 1.25 mmol/l (an average of 21% as compared to 10% in the other group). CONCLUSION: When changing from high Ca dialysate (1.75 mmol/l) to dialysate with a Ca concentration of 1.25 or 1.35 mmol/l, close attention to PTH control has to be paid during the initial months of treatment. Adequate control of plasma levels of iCa, P and PTH could be achieved with both lower Ca dialysates without either hypercalcemia or use of Al-containing P binders in the majority of patients. The small number of patients treated with Al-containing P binders, however, would probably benefit from dialysis fluids with even lower Ca concentrations.

Intake of essential and toxic trace elements in a random sample of Danish men as determined by the duplicate portion sampling technique.

Average daily intakes of essential and toxic trace elements from self-selected diets consumed by 100 men, selected as a random sample among the population of 30-34 year-old men in one urban and two rural areas of Denmark, were determined by the analysis of 48 h duplicate food portions. Median daily dietary intakes were 11.3 mg for zinc, 1.1 mg for copper, 11.3 mg for iron, 51 micrograms for selenium, 3.9 mg for manganese, 99 micrograms for molybdenum, 7 micrograms for lead and 11 micrograms for cadmium. Median dietary intake of mercury was below the detection limit. The observed nitrogen, sodium and potassium intakes were about 25% lower than the average total daily excretion of these constituents. It is therefore assumed that dietary intakes of nutrients during the duplicate portion sampling period were reduced by about 25% and that the observed intakes of trace elements can be regarded as minimum estimates of habitual intake. Taking this into consideration, it is concluded that the content of essential trace elements in Danish diets seems to be adequate and the amounts of the elements lead, mercury and cadmium are of little concern as regards health aspects.

Zinc in mononuclear leucocytes in alcoholics with liver cirrhosis or chronic pancreatitis and in patients with Crohn's disease before and after zinc supplementation.

Mononuclear leucocyte zinc was determined together with serum zinc, albumin and serum alkaline phosphatase activity before and after zinc supplementation (2 x 50 mg of zinc-gluconate daily during 3 months) in patients with alcoholic liver cirrhosis (n = 10), alcoholic chronic pancreatitis (n = 10) and Crohn's disease (n = 10). Initial mononuclear leucocyte zinc concentrations did not differ between the patient groups and the reference group (n = 10), whereas initial serum zinc values were lower in the patients with alcoholic liver cirrhosis and Crohn's disease. This difference disappeared, however, when serum zinc concentrations were corrected for albumin levels, which were lower in all the patient groups. Higher initial activity of serum alkaline phosphatase was found in the alcoholic patients. In all the patient groups serum zinc concentrations increased significantly after zinc supplementation. Only in patients with Crohn's disease was there also an increase in serum alkaline phosphatase and albumin. Mononuclear leucocyte zinc did not respond to zinc supplementation in any of the patient groups. The results of our study indicate that mononuclear leucocyte zinc is not a sensitive indicator of marginal zinc deficiency.

Concentration of nickel and chromium in serum: influence of blood sampling technique.

In the determination of nickel and chromium in serum, contamination is the most important source of error. In this study the influence of needle type and collection device was investigated. For each of 20 subjects the concentrations of nickel and chromium in serum obtained by the following techniques of blood collection were compared: closed collection system (acidwashed polyethylene syringes) + (A) steel needle (Terumo), (B) teflon i.v. cannula (Abbocath-T), and (C1) teflon i.v. cannula (Venflon); (C2) open collection system (acidwashed polyethylene tubes) + teflon i.v. cannula (Venflon). For each technique the first 5 ml of blood were discarded. No statistically significant differences were found between serum concentrations of nickel and chromium in specimens collected with the sampling techniques A, B, C1 and C2. This study has shown that identical results for concentrations of nickel and chromium in serum are obtained independent of whether a steel needle or a teflon i.v. cannula is used for blood sampling, provided the first 5 ml of blood are discarded. Likewise, identical results are obtained independent of whether specimens are collected in a closed or an open collection system, provided collection devices are acidwashed and sampling takes place under hospital conditions.

A method for determination of zinc in mononuclear leucocytes.

A method for the determination of the concentration of zinc in a well-characterized fraction of mononuclear leucocytes from human blood is described. Leucocytes were separated from whole blood by use of the one-step sodium metrizoate/Ficoll procedure. The cell suspensions obtained by the separation procedure had the following composition (mean, range) (N = 15): 82% (70-85%) lymphocytes, 15% (10-15%) monocytes and 4% (2-10%) neutrophils. The ratio of platelets to leucocytes was 1:1 (1:1-1.5). Cell pellets were sonicated before zinc analysis by flame atomic absorption spectrophotometry. 10 healthy volunteers (5 males and 5 females) aged 21-45 years, median age 33 years, were studied. The concentration of zinc in mononuclear leucocytes was 1.14 +/- 0.14 mumol/10(10) cells or 156 +/- 8 mumol/g protein (mean +/- SD).

Serum selenium concentration in maternal and umbilical cord blood. Relation to course and outcome of pregnancy.

The present knowledge of the role of selenium in human fetal and neonatal development is sparse. In this study we measured serum selenium concentrations in maternal and umbilical cord blood from 500 Danish mothers at delivery, looking for a relationship between various maternal and fetal complications and selenium values. In mothers with uncomplicated pregnancies and deliveries serum selenium concentrations were 0.84 +/- 0.19 mumol/l (mean +/- SD), whereas in cord blood from full-term babies born adequate for gestational age and with no malformations serum selenium concentrations were 0.60 +/- 0.11 mumol/l (mean +/- SD). Mothers who received mineral tablets (other than iron preparations) during pregnancy had significantly higher serum selenium values than unsupplemented mothers (0.92 versus 0.70 mumol/l) (p less than 0.001). Infants of mineral-supplemented mothers also had significantly higher serum selenium values than infants of unsupplemented mothers (0.62 versus 0.58 mumol/l) (p less than 0.001). Preterm infants had significantly lower serum selenium concentrations than full term infants (0.54 versus 0.60 mumol/l) (p = 0.01), whereas infants small for gestational age did not differ in serum selenium concentrations from infants adequate for gestational age. Serum selenium concentrations in malformed infants tended to be lower than in normal infants (0.55 versus 0.60 mumol/l) (p = 0.09), but the difference was not statistically significant, probably due to the small number. Serum selenium concentrations in mothers with various complications during pregnancy and delivery did not differ from values in mothers with uncomplicated pregnancies and deliveries.

Serum zinc and copper concentrations in maternal and umbilical cord blood. Relation to course and outcome of pregnancy.

Abnormal serum zinc and copper concentrations in pregnant women have been associated with a number of maternal and foetal complications during pregnancy and delivery. However, the results of previous studies are contradictory and few large scale studies have been reported. In this study we measured serum zinc and copper concentrations in maternal and umbilical cord blood from 500 Danish mothers at delivery, looking for an association between serum zinc and copper levels and various maternal and foetal complications. Preterm infants (n = 30) had significantly lower serum copper concentrations than reference infants (n = 346) (p = 0.01), whereas there was no difference in serum zinc concentrations. Mothers of preterm infants (n = 34) did not differ in serum zinc or copper concentrations from reference mothers (n = 220). Small for date infants (n = 37) and mothers of small for date infants (n = 47) had higher serum copper levels than reference infants and mothers (p = 0.02 and p = 0.04, respectively), whereas there was no difference in serum zinc concentrations. Serum zinc and copper concentrations in malformed infants (n = 14) and their mothers (n = 17) did not differ from concentrations in reference infants and mothers. Serum zinc and copper concentrations in mothers with various other complications during pregnancy and delivery did not differ from values in mothers with normal pregnancies and deliveries.

Long-term effects of intermittent oral alphacalcidol, calcium carbonate and low-calcium dialysis (1.25 mmol L-1) on secondary hyperparathyroidism in patients on continuous ambulatory peritoneal dialysis.

OBJECTIVES: (i) To examine the effect of alphacalcidol [1 alpha(OH)D3] given as an oral dose twice weekly in combination with CaCO3 and low-calcium dialysis (1.25 mmol L-1) on the secondary hyperparathyroidism in continuous ambulatory peritoneal dialysis (CAPD). (ii) To examine the changes in peritoneal mass transfer for calcium, phosphorus, magnesium, lactate, creatinine, urea, glucose, pH and albumin after shift to low-calcium dialysis solution. DESIGN: An open study in patients on CAPD. SETTING: Renal division, Rigshospitalet, Copenhagen. SUBJECTS: Thirty-nine patients were included and completed 12 weeks of treatment. Thirty of the patients completed 52 weeks of treatment. A peritoneal equilibrium test (PET) was performed in seven patients. INTERVENTIONS: Following two sets of blood samples obtained as basal values the calcium concentration was reduced in the dialysis fluid from 1.75 mmol L-1 to 1.25 mmol L-1. Increasing doses of oral 1 alpha(OH)D3 were then administered under careful control of p-ionized calcium (p-Ca2+) and p-inorganic phosphate (p-P1). Blood samples were obtained every 2-4 weeks for 52 weeks. PET was performed using standard dialysis fluid and 1 week later using low-calcium dialysis fluid after a preceding overnight dwell. Two litres of glucose 22.7 mg mL-1 were used. MAIN OUTCOME MEASURES: Intact parathyroid hormone (PTH), p-Ca2+, p-P1, doses of CaCO3, doses of 1 alpha(OH)D3, peritoneal mass transfer for calcium, inorganic phosphate, magnesium, lactate, creatinine, urea, glucose and albumin. RESULTS: Thirty nine patients with initial PTH values 144 +/- 26 pg mL-1 were followed for 12 weeks and 30 patients for 52 weeks. A negative calcium balance was induced after shifting to low-calcium dialysis fluid. After 2 weeks of treatment a significant increase of PTH by approximately 60% and a small but significant decrease of p-Ca2+ was observed. After 12 weeks of treatment with increasing doses of 1 alpha(OH)D3 and CaCO3, PTH was again reduced to levels not significantly different from the initial values. After 52 weeks of treatment no deterioration of the secondary hyperparathyroidism was seen. CONCLUSIONS: A calcium concentration of 1.25 mmol L-1 in the CAPD dialysate made it possible to reduce the amount of aluminium-containing phosphate binder, to increase the doses of CaCO3 and to use pulse oral 1 alpha(OH)D3 without causing severe hyper-calcaemia in the patients. After a short elevation of PTH, the PTH levels remained at normal or near normal levels and the long-term results clearly demonstrated that an aggravation of the secondary hyperparathyroidism could be inhibited.

Influencing a partner to use a condom. A college student perspective.

PIP: Many heterosexuals continue to engage in unprotected sexual intercourse despite the risk of contracting AIDS and other sexually transmitted diseases. When sex partners do not initially agree upon condom use, influence strategies may be used to persuade one to either use or not use condoms. The authors examined the opinions and experiences of 393 college students with condom power strategies. Participants were recruited from introductory psychology courses at UCLA and were of mean age 19 years. Overall, they gender-typed strategies as feminine when the goal was to persuade a partner to use condoms and masculine when trying to avoid condom use. Effectiveness and comfort ratings of the strategies varied by student gender and tactic being evaluated. Gender differences were also noted in students' actual experiences with the strategies. Men used seduction most often when trying to encourage condom use, while women most often withheld sex. To encourage avoiding condom use, men were more likely than women to use seduction, reward, and information.^ieng

Enhancement of the stimulatory effect of calcium on aldosterone secretion by parathyroid hormone.

In previous clinical investigations on uremic patients we found a stimulatory effect of the presence of hyperparathyroidism on the Ca(2+)-induced secretion of various hormones, i.e. aldosterone and vasopressin. The present investigation, therefore, examined the possible effect of PTH on the calcium-mediated aldosterone secretion from isolated, purified zona glomerulosa cells obtained from the rat. After washing the cells and after 30 min of preincubation Ca2+ was added to the preparations at concentrations from 0.5 to 2.0 mmol and PTH(1-84) or PTH(1-34) were added at concentrations from 10(-7) to 10(-10) M. The cells were then incubated for 120 min and aldosterone measured in the supernatant. The aldosterone response to Ca2+ stimulation--without PTH added--served as baseline controls, while cell preparations with ACTH 10(-6) M added secured the viability and responsiveness of the cells. In all cell preparations with PTH(1-84) as well as PTH(1-34) added the aldosterone responses to a certain Ca2+ concentration increased significantly by up to 200% (p < 0.001) above baseline values. It is suggested that PTH may have a Ca2+ ionophore-like effect on endocrine glands, which are not normally related to PTH and thus enhance the calcium-stimulated hormone secretion. The hypothesis is raised that this phenomenon may take place in uremia during the state of secondary hyperparathyroidism.

Randomized crossover study comparing the phosphate-binding efficacy of calcium ketoglutarate versus calcium carbonate in patients on chronic hemodialysis.

The objective of the study was to evaluate the phosphate-binding efficacy, side effects, and cost of therapy of calcium ketoglutarate granulate as compared with calcium carbonate tablets in patients on chronic hemodialysis. The study design used was a randomized, crossover open trial, and the main outcome measurements were plasma ionized calcium levels, plasma phosphate levels, plasma intact parathyroid hormone (PTH) levels, requirements for supplemental aluminum-aminoacetate therapy, patient tolerance, and cost of therapy. Nineteen patients on chronic hemodialysis were treated with a dialysate calcium concentration of 1.25 mmol/L and a fixed alfacalcidol dose for at least 2 months. All had previously tolerated therapy with calcium carbonate. Of the 19 patients included, 10 completed both treatment arms. After 12 weeks of therapy, the mean (+/-SEM) plasma ionized calcium level was significantly lower in the ketoglutarate arm compared with the calcium carbonate arm (4.8+/-0.1 mg/dL v 5.2+/-0.1 mg/dL; P = 0.004), whereas the mean plasma phosphate (4.5+/-0.3 mg/dL v 5.1+/-0.1 mg/dL) and PTH levels (266+/-125 pg/mL v 301+/-148 pg/mL) did not differ significantly between the two treatment arms. Supplemental aluminum-aminoacetate was not required during calcium ketoglutarate treatment, while two patients needed this supplement when treated with calcium carbonate. Five of 17 (29%) patients were withdrawn from calcium ketoglutarate therapy within 1 to 2 weeks due to intolerance (anorexia, vomiting, diarrhea, general uneasiness), whereas the remaining 12 patients did not experience any side effects at all. The five patients with calcium ketoglutarate intolerance all had pre-existing gastrointestinal symptoms; four of them had received treatment with cimetidine or omeprazol before inclusion into the study. Calculations based on median doses after 12 weeks showed that the cost of the therapy in Denmark was 10 times higher for calcium ketoglutarate compared with calcium carbonate (US$6.00/d v US$0.65/d). Calcium ketoglutarate may be an effective and safe alternative to treatment with aluminum-containing phosphate binders in patients on hemodialysis who are intolerant of calcium carbonate or acetate because of hypercalcemia. However, care must be exercised when dealing with patients with pre-existing gastrointestinal discomfort. Due to the high cost of the therapy, calcium ketoglutarate should be used only for selected patients.

Myogenic oscillatory mechanism for opossum esophageal smooth muscle contractions.

We evaluated the control of phasic contractions in opossum esophageal circular smooth muscle by determining the contractile response in vitro to agents that cause membrane depolarization and excitation by different mechanisms. Transverse muscle strips taken from different sites along the length of the smooth muscle esophagus were exposed to progressively increasing concentrations of tetraethylammonium (1-30 mM), K+ (4.6-30 mM), or bethanechol (10(-6) to 10(-2) M). In normally inactive esophageal circular smooth muscle, tetraethylammonium and high K+ concentration elicited phasic contractions that were not blocked by atropine and tetrodotoxin. Bethanechol, an M2 muscarinic receptor agonist that acts selectively on smooth muscle, elicited phasic contractions that were not blocked by tetrodotoxin. We conclude that a latent myogenic oscillatory mechanism for control of phasic contractions exists in esophageal circular smooth muscle and that it may be activated by nonspecific excitation of the smooth muscle membrane. We suggest that this myogenic oscillatory mechanism is likely excited and modulated by nerves.

Myogenic mechanism for peristalsis in opossum smooth muscle esophagus.

We studied the propagation of phasic contractions initiated by tetraethylammonium (TEA, 1-10 mM), high K+ concentration (10-30 mM), and bethanechol (10(-6) to 10(-2) M) in a whole organ in vitro preparation of the opossum smooth muscle esophagus. TEA initiated phasic contractions that began at all sites along the smooth muscle esophagus and propagated in both directions with a velocity similar to that of primary peristalsis. Blockade of neural transmission by tetrodotoxin (TTX, 10(-7) M) did not prevent contraction propagation. Although a majority of contractions initiated by TEA did not propagate the full length of the esophageal specimen, with the addition of TTX most contractions initiated by TEA did propagate the full specimen length in either direction. High K+ concentration and bethanechol elicited propagated contractions similar to those initiated by TEA. We conclude that 1) a myogenic mechanism exists for propagation of contractions along the smooth muscle esophagus and 2) intramural inhibitory nerves modulate the extent of myogenic propagation in the ascending as well as descending direction. We suggest that esophageal peristalsis may occur by myogenic propagation of contractions that are normally initiated in the proximal smooth muscle esophagus by excitatory nerves. Intramural inhibitory nerves may inhibit retrograde propagation as well as mediate descending inhibition in advance of the peristaltic wave.