[Nutritional and Functional assessment of peritoneal dialysis patients in the clinical practice: Report from MITO-DP Group]. / Valutazione Nutrizionale e Funzionale dei pazienti in dialisi peritoneale nella pratica clinica: l'esperienza del Gruppo Medico-Infermieristico Toscano di Dialisi Peritoneale (M.I.TO.-DP).

Nutritional abnormalities and physical inactivity are risk factors of increased morbidity and mortality in patients with ESRD. Identify and define malnutrition, in particular protein-energy depletion (PEW), is an important task in the management of renal patients. The aim of this multicenter observational study was to implement the assessment of nutritional status and functional capacity in patients on peritoneal dialysis, including tests and validated methods which are relatively easy to apply in daily clinical practice. The study includes all the 133 prevalent patients (80 m, 53 f, age 65 14 years), in peritoneal dialysis treatment (vintage 26 19 months) in 9 centers in Tuscany. We performed anthropometry, bioimpedance (BIA), clinical biochemistry, evaluation of habitual physical activity (RAPA tests) and performance (Sit-To-Stand test), appetite-evaluation questionnaire, and indices including the Malnutrition Inflammation Score (MIS), Geriatric Nutrition Risk Index (GNRI), Charlson comorbidity index, Barthel and Karnowsky index. The latter showed a condition of dependence in 7.2% and 19.7% of cases, respectively. Poor appetite was recorded in 48.2%. The majority of patients fell within the overweight / obesity range (51%) with waist circumference values associated with increased cardiovascular risk in 51% of males and 60% of females. At the BIA analysis, a BCMI <8 kg/m2 was detected in 39% of patients; an estimated protein intake <1.0 g / kg/d was found in 59% of cases; 34% of patients had serum albumin <3.5 g / dl; control of acidosis was good (bicarbonate 25.4 3.8 mM) but hyperphosphatemia was present in 64.6% of patients. A condition of sedentary or light physical activity was reported by 65.1% of patients, vigorous activity only by 11.9%. The 86.5% of patients able to perform the Sit-to-stand test reported a lower than the reference values for age and sex. A diagnosis of PEW was possible in 8% of our series, while a MIS score> 11, indicative of PEW, took place in 12.7% of cases. The values of the MIS correlated directly with age and the degree of comorbidity and inversely with the sit-to-stand test, RAPA tests and appetite level. The data in this study show that single tests indicative of malnutrition disorders are frequent to be found in our series of peritoneal dialysis patients. However, a diagnosis of PEW is quite infrequent. A large percentage of patients are overweight with increased abdominal adiposity, and reduced cell mass and protein intake below recommended levels; the level of habitual physical activity is low, and the level of physical capability is scarce. Therefore it is conceivable a nutritional counseling intervention to increase the intake of proteins, limiting the phosphorus and (when indicated) energy intake and to stimulating spontaneous physical activity or arranging assisted programs for functional rehabilitation. Close monitoring of the nutritional status and implementation of programs of adapted physical activity should have a prominent role in the clinical management of patients on peritoneal dialysis.

Association between vitamin D receptor gene polymorphism and nephrolithiasis.

AIMS: To study the distribution of vitamin D receptor (VDR) gene alleles in hypercalciuric and nonhypercalciuric nephrolithiasis patients, hypothesizing that distinct biochemical parameters would be associated with different VDR genotypes. METHODS: 12 hypercalciuric, 15 normocalciuric nephrolithiasis patients, and 150 healthy subjects were recruited. The individual genetic pattern for VDR was evaluated by DNA extraction followed by polymerase chain reaction amplification of the VDR gene and digestion with the restriction enzyme BsmI. RESULTS: In the hypercalciuric group, Bb patients represented 50% (6/12); bb patients 33% (4/12), and BB cases were 16% (2/12). The VDR frequency distribution was not statistically different in hypercalciuric patients and controls (Bb 72%; bb 16%; BB 12%). In the nonhypercalciuric group, the prevalence of the bb genotype (7/15; 47%) was thrice the percentage of control subjects, while the percentage of BB patients was similar to that of the control group (2/15; 13%). Patients with the bb haplotype exhibited a higher daily urinary calcium excretion. Among hypercalciuric patients, after a calcium-restricted diet, bb patients showed a 39% reduction in daily urinary calcium excretion in comparison with a nonsignificant 13% reduction observed in BB subjects (p = 0.004). CONCLUSIONS: The effects of VDR gene polymorphism on calcium metabolism contribute to the understanding of the pathogenesis of urinary calculi.

Lack of association between body weight, bone mineral density and vitamin D receptor gene polymorphism in normal and osteoporotic women.

In an ethnically homogeneous population of women living in Tuscany, Italy, the relationships between age, body weight, bone mineral density and the vitamin D receptor (VDR) gene polymorphism were studied, with the objective of recognizing patients at risk for osteoporosis. In 275 women bone mineral density was measured by Dual Energy X-rays Absorptiometry (DEXA). In 50 of them the individual genetic pattern for VDR was evaluated by DNA extraction followed by PCR amplification of the VDR gene, and digestion with the restriction enzyme BsmI. Age and bone mineral density were inversely related (R2 = 0.298). Body weight was associated with bone mineral density (R2 = 0.059), but not with age. In osteoporotic women, mean (+/- SD) body weight was 59.9 +/- 6.5 Kg, lower than that recorded in non osteoporotic women (64.2 +/- 9.4 Kg), even though not significantly different (p = 0.18). No association was found between VDR gene polymorphism, bone density or body weight. The performance of anthropometric and genetic components appear to be poor, and, at least for the time being, bone mineral density measurement by means of MOC-DEXA represents the optimal method to detect women at risk for postmenopausal osteoporosis.

Bone mineral density and anthropometric measures in normal and osteoporotic men.

In an ethnically homogeneous men population living in Tuscany, Italy, the relationship between age, height, body weight and bone mineral density were studied. In 50 men bone mineral density was measured by Dual Energy X ray Absorptiometry (DEXA). 13 subjects (26%) were osteoporotic. Age and bone mineral density were not related (R2 = 0.052). Bone mineral density was associated with body weight (R2 = 0.303), and height (R2 = 0.155). In osteoporotic men, mean (+/- SD) body weight was Kg. 65.8 +/- 11.2, lower than that recorded in non osteoporotic men, Kg. 77.3 +/- 10.2, (p = 0.0013). Age in osteoporotic and non-osteoporotic men did not differ (53.8 +/- 13.6 yrs and 60.9 +/- 11.8 yrs, respectively; p = 0.077). In conclusion, anthropometric factors, as predictors of bone disease, behave differently in women and men.

Influence of static magnetic field on the antiproliferative effects of vitamin D on human breast cancer cells.

We describe the effect of a 0.2 tesla (T) static magnetic field generated by a magnetic resonance tomograph and of vitamin D treatment on a human breast cancer cell line (MCF-7). Cell damage and proliferation were monitored by measuring the incorporation of [3H]thymidine in duplicating DNA and by the clonogenic assay. [3H]Thymidine incorporation in MCF-7 was stimulated by vitamin D at low doses (10(-12)-10(-10) M), whereas it was inhibited at higher concentrations (10(-9)-10(-6) M). Magnetic field treatment (0.2 T) decreased [3H]thymidine incorporation in human breast cancer cells, eliminating the proproliferative effect of low doses of vitamin D, and enhanced the vitamin D antiproliferative effect, further reducing [3H]thymidine incorporation, from -12.5% (P < 0.05) to -66.7% (P < 0.001), over the range of 10(-9) to 10(-6) M. In the clonogenic assay, ability of MCF-7 to form colonies was inhibited by vitamin D 10(-9) M and above, whereas 3-h exposure to 0.2 T magnetic field had no effect on the number of cell colonies formed. In conclusion, vitamin D treatment yields a permanent antiproliferative effect, while magnetic field exposure only temporarily slows down cellular growth. These findings suggest that therapy with vitamin D may prove beneficial for chemoprevention or treatment of breast cancer. Static magnetic field, alone or in combination, does not appear to represent an effective candidate for breast cancer therapy, at least at the intensity used in the present study.

Vitamin D receptor gene polymorphism is associated with metastatic breast cancer.

The vitamin D receptor (VDR) has been detected in breast tumor cells. We tested the hypothesis that VDR gene polymorphism might influence the outcome of women affected by breast cancer. A total of 88 breast cancer patients were recruited: 50 women were affected by newly diagnosed breast cancer whereas 38 women suffered from relapsing disease. The individual genetic pattern for VDR was evaluated by DNA extraction followed by PCR amplification of the VDR gene, and digestion with the restriction enzyme BsmI. In 167 healthy women, participating in the osteoporosis prevention trial and being used as a control, we detected 121 Bb heterozygotes (72%), 26 homozygotes for the bb alleles (16%), and 20 homozygotes for the BB alleles (12%). In the newly diagnosed breast cancer group the occurrence of Bb patients was 58% (29/50); bb patients represented 22% (11/50), and BB cases were 20% (10/50). The VDR frequency distribution in the control and primary disease patient groups was not statistically different. In the metastatic cancer group, the prevalence of the bb genotype (14/38; 37%) was double the percentage of control subjects, whereas the percentage of BB women with metastases was half the control group (2/38; 5%). Women who were homozygous bb appeared to have almost a four times higher risk of developing metastases than BB women. Whatever the molecular mechanisms underlying the VDR effects in cancer cells, we believe that the VDR gene polymorphism may represent an important determinant in the evaluation of women affected by breast cancer and might help design targeted therapy.

Cellular proliferation and second messenger formation altered by dialysis membranes.

BACKGROUND: In this study we investigated the effect of different dialysis membranes on the clonal murine haematopoietic cell line 32D cells transmembrane signalling machinary, monitored by 1,2-diacylglycerol (DAG) formation, and on their ability to respond to the physiological growth factor interleukin-3 (IL-3). METHODS: Cells were exposed to dialysers (cuprophane, CU; polysulphone, PS; cellulose diacetate, CA; polyacrylonitrile, AN69; polymethylmethacrylate, PMMA; cellulose triacetate, CT; polyamide, PA; and polycarbonate, PC); they were collected, counted, and treated with physiological amount of IL-3. Cell proliferation was monitored as incorporation of radioactivity in duplicating DNA. DAG was measured by thin-layer chromatography in cell labelled with tritiated glycerol overnight. RESULTS: CU and PA stimulated cell proliferation in comparison with resting cells. PS and TC did not significantly affect thymidine incorporation either in IL-3-stimulated, or in resting cells. Cells exposed to AN69, PC, and CA showed depressed basal incorporation of thymidine (70, 54 and 56% of controls respectively) but retained the ability to respond to IL-3 in a manner not statistically different from controls. PMMA reduced thymidine incorporation both in basal condition and after IL-3 stimulation CU and PC activated early cell signalling (1.95 x and 1.31 x respectively, DAG increase over control), while PA and TC depressed DAG generation (0.38 x and 0.47 x respectively, DAG increase over control). PS, CA, AN69, and PMMA did not stimulate DAG generation. CONCLUSIONS: Alternations of intracellular mitogenic signalling appear to correlate with the ability to make a cell competent for function. These results might help to elucidate the effect of different dialysers, at the molecular level, on the blood cell behaviour in vivo.

[The determination of BB genotype of vitamin D receptors identifies patients at risk for osteoporosis]. / La determinazione del genotipo BB del recettore della vitamina D identifica pazienti a rischio di osteoporosi.

The gene responsible for peak bone mass has been recently identified as the gene coding for the Vitamin D Receptor (VDR); there exist two alleles, termed "B" and "b", determining a typical allelic polymorphism. We determined the VDR genotype of 50 young post-menopausal women (mean age: 56 years), and measured bone density by Dual Energy X ray Absorptiometry (DEXA) twice: at the beginning of the study and after one year. VDR genotype was determined using the DNA extracted from hair cells, thus avoiding the use of blood samples. The frequency of VDR genotypes (BB or bb homozygous; Bb heterozygous) was approximately the same in the two groups of subjects (i.e., normal controls and osteoporotic women). The bone density of normal subjects (36) was measured for the second time one year after the first measurement. All BB homozygous subjects showed significantly decreased bone density values; 50% of them showed values below 0.750 g/cm2 at the second measurement, thus being classified as osteoporotic. However, neither bb homozygous nor Bb heterozygous subjects showed any significant decrease in bone density values (about 4% of the initial value). Therefore, determining the VDR genotype was critical for identifying the subjects who were normal at the first measurement, but had markedly decreased bone density values later, thus being at risk of developing osteoporosis.

Second messenger formation altered by different dialysis membranes in human leukocytes.

A number of agents stimulate transmembrane cell-signaling in different cell types through the formation of the second messenger diacylglycerol (DAG) which activates protein kinase C (PKC). The aim of this study was to investigate phospholipase C activation, DAG formation, and cellular adhesion to dialysis membranes after simulated dialytic treatment of either human leukocytes or clonal hematopoietic cells. Cells were circulated for 60 minutes in a closed-loop dialysis system using three different dialyzers: cuprophan (CU), polysulphone (PS), and AN69 (PAN). Another cell aliquot was left within the dialyzers without circulation. Samples were taken at different time intervals and cells counted. Cells were labeled with tritiated glycerol overnight, and DAG was measured by thin-layer chromatography. Our data showed that cells tended to adhere with more efficiency to CU than to the synthetic dialyzers. Circulation in the in vitro dialysis circuit resulted in the rapid (5 min) formation of [3H]DAG (CU 1.95-; PS 1.34-; PAN 1.24-fold increase over untreated cells). The DAG level peaked at 15 to 30 minutes and remained constant thereafter (CU 1.70; PS 1.96; PAN 1.66). When we measured DAG formation in cells that had been kept in the dialyzers without circulation, we found that cells exposed to CU showed a much higher and rapid activation than those exposed to PS or PAN, as if CU per se was able to activate early cell signaling (CU 1.95-; PS 0.97-; PAN 1.09-; DAG, -fold increase over control).(ABSTRACT TRUNCATED AT 250 WORDS)

HCV incidence in a dialysis center: preliminary reports.

Incidence of seroconversion to anti-HCV from December 1989 to May 1991 was evaluated in patients and in their sexual partners. In December '89, 13 of 66 and in May '91, 26 of 75 patients were HCV positive. 9 of 13 new, seroconverted patients had been transfused. Seroconverted mean dialytic age was lower than that of previous HCV-positive patients. All the sexual partners were HCV negative. Blood transfusion seems to be the main risk factor for HCV infection, while environmental contamination is still debatable.

Effects of TSH on cAMP levels and thyroid hormone release in human thyroid 'autonomous' nodules: relationship with iodothyronine and iodine content in thyroglobulin.

The effect of TSH on the adenylate cyclase-cAMP system and in vitro iodothyronine release, together with the iodothyronine and iodine content of 19s thyroglobulin, were studied in seven clinically euthyroid patients with autonomous thyroid nodules. Basal cAMP and cGMP content together with phosphodiesterase and protein-kinase activities were normal in nodular, and suppressed in extranodular tissue. TSH-dependent cAMP accumulation was reduced in nodular tissue, but normal in the suppressed extranodular tissue. In vitro TSH-dependent iodothyronine release from nodular and extranodular tissue was absent. Thyroxine and iodine content of thyroglobulin extracted from nodular tissue was reduced, while triiodothyronine content was normal but with a low T4/T3 ratio. In extranodular tissue T3, T4 and iodine contents were reduced. In conclusion, autonomous thyroid nodules produced a poorly iodinated thyroglobulin leading to preferential T3 secretion with increased circulating free thyroid hormones even in clinically euthyroid patients.

Dissociation in the response of the adenylate cyclase system to thyrotropin and prostaglandin E2 in human thyroid carcinoma tissue.

Because the existence of a damaged thyrotropin (TSH) receptor in thyroid tumors may be relevant in the perspective of a correct postsurgical therapy, the effect of TSH on cAMP intracellular accumulation in thyroid carcinoma (N = 16), follicular adenoma (N = 27) and normal tissue (N = 30) slices was studied and compared with that of nonspecific stimulus of thyroid adenylate cyclase-cAMP system, such as prostaglandin E2 (PGE2). While in all follicular adenomas a normal behavior of basal and post-TSH and -PGE2 stimulated cAMP accumulation was observed, basal cAMP levels were generally higher than in controls in 14 differentiated carcinomas, responses to TSH were reduced or absent, and response to PGE2 was close to normal. On the contrary, in two anaplastic carcinomas, both TSH and PGE2 produced a negligible modification of cAMP levels. Thus, in undifferentiated carcinomas, the adenylate cyclase-cAMP system seems to be altered; in differentiated carcinomas, the catalytic part of the system appears unaffected as it is PGE2-responsive. Therefore, some hypotheses are ruled out as an explanation for decreased sensitivity to TSH of differentiated carcinomatous cells.

Prostacyclin stimulates the adenylate cyclase system of human thyroid tissue.

Since Prostacyclin (PGI2) is a major product of arachidonic acid metabolism in the human thyroid, we have studied the effects of PGI2 on cAMP accumulation in human thyroid slices and cultured thyrocytes. In both systems, PGI2 caused a dose- and time-dependent increase of cAMP accumulation with higher potency and efficacy than PGE2. Two optically active isomers of 5,6-dihydro-PGI2, i.e. stable synthetic analogs of PGI2, had qualitatively similar effects to PGI2. The relative potency ratio between the alpha- and beta- isomer as well as their potency compared to PGI2 were substantially similar to their potency in inhibiting human platelet aggregation. In thyroid slices, PGI2 and its stable analogs had a greater effect than TSH in causing cAMP accumulation; however, in contrast to TSH, this effect was not associated with increased iodothyronine release except at maximal PGI2 concentrations. TSH had no detectable effect on thyroidal PGI2 synthesis and release. In cultured thyrocytes the effects of PGI2 and its stable analogs were considerably less than those obtained with TSH and required higher concentrations. Such a discrepancy was not found in the case of PGE2. These findings suggest the existence of a specific PGI2-responsive adenylate cyclase system in human thyroid cells other than thyrocytes, of possible physiologic significance.