Cultures of human osteoblastic cells from dialysis patients: influence of bone turnover rate on in vitro selection of interleukin-6 and osteoblastic cell makers.

The factors contributing to renal osteodystrophy are still incompletely characterized. A variety of cytokines and growth factors appear to have ill-defined roles in this disease. Our aim is to compare osteoblastic cell growth and different osteoblastic markers in vitro with histomorphometric bone parameters and some serum bone-turnover markers in vivo in dialysis patients with either high- (HTBD) or low-turnover (LTBD) bone disease.

[Methods to assess the ex vivo growth capacity of mesothelial cells obtained directly from peritoneal effluent].

The anatomical and functional integrity of mesothelial cells (MC) is necessary for peritoneal membrane stability. At present, there is no satisfactory method to assess MC function and regenerative capacity in individual peritoneal dialysis (PD) patients. MC may be cultured from peritoneal biopsy specimens, but peritoneal biopsy is an invasive procedure that cannot be performed serially.

Influence of skeletal site of origin and donor age on osteoblastic cell growth and differentiation.

Bone loss with aging may be due, at least in part, to inadequate bone formation. Moreover, the process of bone aging is known to follow a different pattern throughout the skeleton. In this study, we examined the cell proliferation rate (area under the cell growth curve, AUC) and the secretion of C-terminal type I procollagen (PICP), alkaline phosphatase (ALP), and osteocalcin (OC) in primary cultures of osteoblastic cells from human trabecular bone.

Influence of skeletal site of origin and donor age on 1,25(OH)2D3-induced response of various osteoblastic markers in human osteoblastic cells.

Age-related bone loss may be a consequence of a lack of osteoblastic formation and/or function. In vitro, the osteoblastic response to 1,25(OH)2D3, an important regulator of osteoblastic function, appears to depend on the stage of osteoblastic maturation. In this study, we examined the response to 1,25(OH)2D3 of C-terminal type I procollagen (PICP), alkaline phosphatase (ALP), and osteocalcin (OC) secretion in primary cultures of osteoblastic cells from human trabecular bone (hOB).

[Bone metabolism in non-cholestatic chronic hepatopathy].

Background: Osteoporosis may be associated with parenchymal hepatopathy and chronic alcoholism. Biochemical studies which are linked with bone metabolism and the bone densitometry may help to understand its physiopathology, before the symptoms appear and its consequences become inevitable.

Patients And Methods: The study of bone metabolism and densitometry has been carried out in a population of 86 males, distributed in 4 groups: group I, control (17 men), group II, patients with chronic hepatopathy without alcoholism (25 patients), group III, chronic alcoholic without hepatopathy (21 patients), and group IV, patients with chronic alcoholic hepatopathy (23 patients).

Effect of polyethylene on osteocalcin, alkaline phosphatase and procollagen secretion by human osteoblastic cells.

We have studied the direct effects of polyethylene particles on osteoblastic function in primary human bone cell cultures. The cells were obtained from trabecular bone fragments of patients undergoing knee reconstructive surgery. When the cells reached confluency, they were subcultured into two flasks, one untreated (control culture) and the other treated with polyethylene particles, and incubated until confluency.

C-terminal parathyroid hormone-related protein inhibits proliferation and differentiation of human osteoblast-like cells.

Parathyroid hormone-related protein (PTHrP) is synthesized by osteoblasts, although its local role in bone is not completely understood. The C-terminal (107-111) region of PTHrP seems to be a potent inhibitor of osteoblastic bone resorption. We studied the effect of this PTHrP domain on the proliferation and synthesis of osteoblastic markers in osteoblast-like cells from adult human bone.

Enzymic determinations with rotating bioreactors and continuous-flow-stopped-flow processing. Determination of choline esters in pharmaceuticals.

The neuromuscular blocking agent, succinylcholine, and the neurotransmitter, acetylcholine, have been determined in pharmaceutical preparations utilizing a sensing unit comprised of a rotating bioreactor and an amperometric detector. The bioreactor consisted of a rotating disk made of Teflon (1 cm id) with cholinesterase (EC 3.1.

Remission of hypercalciuria in patients with tuberculosis after treatment.

The hypercalciuria evolution and other bone metabolism parameters were evaluated in patients with tuberculosis after treatment. Twenty-two patients with tuberculosis and 54 normal subjects were studied; they consumed an average diet (calcium intake 1000 mg/day). Ten of these patients and nine normal subjects were also studied after a low calcium diet (400 mg/calcium/day) and after a load of oral calcium of 1000 mg (calcium absorption test).

Alcohol biosensor based on alcohol dehydrogenase and Meldola Blue immobilized into a carbon paste electrode.

A yeast alcohol dehydrogenase amperometric carbon paste-based biosensor, with Meldola Blue as a mediator and a dialysis membrane with a very small molecular weight cut-off for protection, is described. The influence of membrane pore size on the stability and overall kinetics of the biosensor is shown using cyclic voltammetry and stationary potential measurements. The operating potential is + 50 mV vs.

[Vitamin D levels in patients with hip fracture in Madrid].

Background: Vitamin D appears to be implicated in the loss of bone mass and its most severe complication is the hip fracture. A change is produced in the metabolism of vitamin D in elderly people although its study has received little attention in many countries.

Methods: With the aim of evaluating vitamin D and its metabolites in the elderly people with hip fracture in our geographic environment (Madrid, Spain), 58 patients with hip fracture over the age of 70, and 39 subjects without a fracture or the similar age were studied.

Determination of Michaelis-Menten and inhibitor constants by an open-closed flow injection approach (Application to the alkaline phosphatase/theophylline system).

An automatic method for the estimation of Michaelis-Menten and inhibitor constants in biochemical systems was developed using an unsegmented open-closed flow manifold, and the Lineweaver-Burk and Dixon plot methods. The methods were applied to both the determination of K(m) of the enzymatic reaction catalyzed by bovine alkaline phosphatase using 4-methylumbelliferone phosphate as substrate, and the determination of the K(i) constant from theophylline as an inhibitor of this biochemical system. The data treatment and comparative results are presented.

Effect of oral calcidiol treatment on its serum levels and peritoneal losses.

Objectives: To evaluate calcidiol serum levels in a group of continuous ambulatory peritoneal dialysis (CAPD) patients and the effect of oral calcidiol treatment on serum levels and peritoneal losses.

Study Design: Twenty patients (13 female, 7 male) were studied for 12-60 months. Their ages ranged 22-72 years (mean 46 +/- 15).

Relations between calcidiol serum levels and bone mineral density in postmenopausal women with low bone density.

The relationship between vitamin D and bone density was studied in 150 selected, mature (45-74), postmenopausal women with a lumbar spine Z score below 0. Vitamin D status was evaluated using calcidiol serum levels. Serum calcitriol and parathyroid hormone (PTH) values were also evaluated in some subjects.

Fluorimetric determination of alkaline phosphatase activity in human serum by use of a flow-through biosensor.

A fluorimetric method for the determination of alkaline phosphatase activity based on the use of a flow-through biosensor is reported. The biochemical basis of the method is the hydrolysis of 4-methyl-umbelliferone-phosphate catalyzed by the analyte with fluorimetric monitoring of the 4-methyl-umbelliferone formed (lambda ex = 365 nm, lambda em = 445 nm). The enhancement of sensitivity achieved when the reaction product is retained on the support packed in the flow-cell makes the method suitable for determination of the analytes in serum samples after 1:50 dilution.

Relation of abnormal composition of lipoproteins to HbA1c levels in non-insulin dependent diabetes.

Plasma lipids and VLDL and HDL composition were studied in a control group of 20 non diabetic subjects and in 31 male middle-age patients with non-insulin dependent diabetes treated by oral hypoglycemic agent glibenclamide and a weight maintaining diet. Data for the diabetics were separated based on haemoglobin A1c of less or greater than 7%. VLDL composition abnormalities were more frequent in the diabetic patients with HbA1c of > 7%.

Serum osteocalcin concentrations in diabetic pregnant women and their newborns.

Osteocalcin and PTH serum levels were measured in 41 insulin-dependent diabetic pregnant women through the three trimesters of pregnancy with a total of 106 determinations of osteocalcin and 137 of PTH. In parallel we quantified these parameters in 90 normal pregnant women throughout the three trimesters of pregnancy. In addition calcitriol, osteocalcin and PTH levels were quantified at delivery in 16 diabetic pregnant women and 16 normal pregnant women at delivery, in cord serum and in the infants during the first days of life.

Evidence of absorptive hypercalciuria in tuberculosis patients.

In patients with granulomatous diseases, disturbances in calcium metabolism have been described. The aim of the study was to evaluate alterations in calcium metabolism in patients with tuberculosis. Forty patients with tuberculosis (TB) were studied in a baseline state (calcium intake 1000 mg/day).

Plasma lipids and VLDL composition in male non-insulin dependent diabetic patients: relation with HbA1c levels.

In this study, plasma lipids and VLDL composition were measured in 22 middle aged male patients with non-insulin dependent diabetes and compared with 15 non-diabetic controls. Data for the diabetics were differentiated on the basis of hemoglobin A1c levels of less than or greater than 7%. Compositional abnormalities of VLDL were more frequent in the diabetic patients with HbA1c of > 7%.

[Correlations of the levels of HbA1c with plasma apoproteins and plasma lipoproteins in type II diabetic patients].

Plasma apolipoproteins from VLDL, LDL and HDL lipoproteins were measured in 56 male patients with age range 50-60 years and noninsulin-dependent diabetes mellitus (type II) and 81 normal volunteers. Diabetic patients were further divided into two subgroups according to the HbA1c (glycated haemoglobin) concentrations, lower than 7% and higher than 7% respectively, after considering that HbA1c levels may be an appropriate index to monitor long-term blood glucose level. The studied groups, control and diabetic patients, were well matched with regard to age, % of smokers, % drinkers and % hypertensive and physical activity.

The pharmacokinetics of a single dose of calcitriol administered subcutaneously in continuous ambulatory peritoneal dialysis patients.

Objectives: To evaluate the kinetics of calcitriol (1,25(OH)2D3) administered subcutaneously.

Study Design: Calcitriol kinetics and efficacy after subcutaneous administration were studied in 13 CAPD patients with varying degrees of increased plasma levels of parathyroid hormone (i-PTH). A single dose of 2 micrograms of calcitriol was administered subcutaneously, and its serum levels at baseline and after 1, 2, 6, 12, and 24 hours were determined.

Influence of calcium intake on calcitriol levels in idiopathic hypercalciuria in children.

Twenty-four children with idiopathic absorptive hypercalciuria (IAH) and a control group (CG) of 11 healthy children were studied. Plasma 1,25-hydroxyvitamin D3 (calcitriol), parathyroid hormone (PTH), calcium (Ca) and phosphate (P) levels were measured during dietary manipulation. The three diets analyzed were: (A) calcium-restrictive diet (400 mg/1.

[Alterations in calcium metabolism in patients with active tuberculosis].

Background: Abnormalities in phosphocalcic and vitamin D metabolism may develop in patients with active tuberculosis (TB). Their incidence and relationship with the disease is not well known, particularly in our area. We have prospectively evaluated 40 patients with TB [(30 with localized TB (LTB) and 10 with disseminated TB (DTB)].