Biomedical subjects

P Jaeger

Publications and source records attributed to P Jaeger.

At least 91 records · Page 5Linked to original sources

PubMed1993

Citrate and calcium effects on Tamm-Horsfall glycoprotein as a modifier of calcium oxalate crystal aggregation.

We measured the effects of Tamm-Horsfall glycoprotein (THP) on calcium oxalate monohydrate (COM) crystal aggregation (Ac) in vitro as well as intrinsic viscosities (Vi) of THP at pH 5.7 and 200 mM NaCl and studied the effects of calcium and citrate on these parameters. THP were isolated from 24-h urines of seven male recurrent calcium stone formers (RCSF) and eight age-matched male healthy volunteers (N, normal). At basal conditions, RCSF-THP inhibited Ac by 28 +/- 10% and normal THP by 60 +/- 6% (P = 0.028). In the presence of calcium, increasing THP concentrations from 16 to 28 and 40 mg/l progressively lowered inhibition by RCSF-THP, but not by N-THP. At 40 mg/l, inhibition by N-THP was 27 +/- 9% vs. -43 +/- 8% by RCSF-THP (P = 0.001), i.e., all stone former THP promoted Ac. With an additional 3.5 mM of citrate, inhibition of Ac was 56 +/- 5% by normal and 34 +/- 6% by stone former THP (P = 0.021), and all seven stone former THP again inhibited Ac. Vi of RCSF-THP was higher than that of N at basal conditions (162 +/- 21 vs. 93 +/- 15 ml/g, P = 0.021) and in the presence of 5 mM calcium (352 +/- 54 vs. 118 +/- 17 ml/g, P = 0.001), i.e., RCSF-THP were more self-aggregated, but not when citrate was added (185 +/- 29 vs. 123 +/- 19 ml/g). (ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Relative hypoparathyroidism and calcitriol up-regulation in hypercalciuric calcium renal stone formers--impact of nutrition.

The issue of secondary hyperparathyroidism in idiopathic hypercalciuria (IH) was addressed in 61 male idiopathic calcium stone formers (SF) who underwent metabolic evaluation on a free-choice diet as well as bone mineral density (BMD) measurements by dual-energy X-ray absorptiometry. They were divided into hypercalciurics (HCSF, n = 30, UCa X V > 7.5 mmol/day) and normocalciurics (NCSF, n = 31, UCa X V < 7.5 mmol/day). At identical blood Ca2+ levels, parathyroid hormone (PTH) was lower in HCSF (25.3 +/- 1.8 pg/ml) than in NCSF (31.4 +/- 1.8 pg/ml, p = 0.017). Since neither fasting urinary hydroxyproline nor pyridinoline/deoxypirdinoline excretions nor BMD values were different between HCSF and NCSF, chronic bone dissolution as the cause of relative hypoparathyroidism in HCSF could be excluded. Despite lower PTH in the face of similar phosphate, Ca2+ and IGF-1 blood levels, however, serum 1,25-dihydroxyvitamin D3 (calcitriol) concentrations were slightly (though not significantly) higher in HCSF than in NCSF (52.8 +/- 3.2 vs. 47.3 +/- 2.9 pg/ml, p = NS), and calcitriol/PTH ratio was elevated in HCSF (2.52 +/- 0.29) vs. NCSF (1.66 +/- 0.15, p = 0.001). Creatinine clearance, significantly higher in HCSF than in NCSF (113 +/- 4 vs. 92 +/- 3 ml/min/1.73 m2, p = 0.0001), was positively correlated with excretion rates of urinary markers of both protein and NaCl intake. Since serum calcitriol levels were positively correlated with creatinine clearance (r = 0.350, slope = 0.288, p = 0.006), up-regulation of calcitriol synthesis with subsequent relative hypoparathyroidism in HCSF is-at least partly-explained by exaggerated protein and sodium consumption.

Absorptiometry, Photon↗

PubMed1993

Diltiazem stimulates parathyroid hormone secretion in vivo whereas felodipine does not.

The impact of two calcium channel blockers of different structure, diltiazem and felodipine, on PTH secretion was studied under hyper- and hypocalcemic conditions. Six healthy volunteers were investigated before and after treatment with felodipine, then after treatment with diltiazem. Under each of these three conditions, they received first a calcium infusion (0.109 mmol/kg over 130 min). Blood was drawn every 5-10 min for measurements of Ca2+ and intact PTH concentrations, and urine was collected over the infusion periods for measurements of calcium and creatinine. Basal levels of Ca2+ and intact PTH concentrations were similar under the three conditions. During calcium infusion, Ca2+ increased linearly from 1.27 to 1.51 mmol/L during the control period. Based on the whole response curve, Ca2+/time, this rise was less marked (P < 0.002) during each of the calcium channel blocker periods than under control conditions, although the three values of urinary calcium excretion were similar. In addition, PTH secretion was less suppressed on diltiazem than on felodipine therapy or during the control period (P < 0.04). During EDTA infusion, Ca2+ decreased in a linear way from 1.27 to 1.07 mmol/L during the control period. Based on the whole response curve, Ca2+/time, this decrease was more marked during felodipine than during diltiazem treatment or in the control period (P < 0.001). Although Ca2+ concentrations did not differ between the control and diltiazem periods, PTH levels were 1.3-fold higher (P < 0.0001) during diltiazem, but similar in the control and felodipine periods. These data demonstrate that diltiazem, but not felodipine, stimulates PTH secretion in vivo in man, with a maximal effect observed under hypocalcemic conditions.

Adult↗

PubMed1993

The tale of parathyroid function in idiopathic hypercalciuria.

At the origin, idiopathic hypercalciuria has been described as a syndrome consisting of normocalcemia, low plasma phosphate levels and abnormally high urinary calcium excretion. The cause of this syndrome was subject to many investigations throughout the years. Two main pathophysiologic hypotheses have been proposed: a) primary intestinal hyperabsorption of calcium, leading to depression of parathyroid hormone (PTH) secretion ("absorptive" hypercalciuria); and b) primary renal tubular leak of calcium which stimulates PTH secretion (secondary hyperparathyroidism). Most of the published studies indicate that intestinal hyperabsorption of calcium with subsequent relative hypoparathyroidism is the primary event causing idiopathic hypercalciuria, and that this occurs as a consequence of increased production of 1,25(OH)2-vitamin D3 (calcitriol). Fasting hypercalciuria, originally taken as evidence for a "renal leak" of calcium, appears to be, at least in part, the consequence of relative hypoparathyroidism.

Calcitriol↗

PubMed1993

[Histiocytosis X of the petrous pyramid in adults. X-ray computed tomographic and MRI aspects].

Two cases are reported of histiocytosis X in young adults, both confined to the petrous bone. In one case the clinical signs were those of a progressive facial palsy, developing over 3 years; the other case had pulsatile tinnitus with clear otorrhoea and symptoms of vestibular deficiency. Computed tomography showed extensive bone destruction by a soft-tissue density process which enhanced strongly after iodinated contrast injection. Magnetic resonance imaging (T1 weighted sequences before and after intravenous gadolinium injection) confirmed the presence of a mass lesion in the petrous bone with contrast medium uptake which showed cystic areas within it: it also showed the absence of extension through the dura mater by the intracranial component which remained extradural. It confirmed the patency of arteries and veins, so enabling a differentiation to be made between histiocytosis X and advanced glomus tumours.

Adolescent↗

PubMed1993

Impact of time-interval after transplantation and therapy with fibrates on serum cholesterol levels in renal transplant patients.

It is unclear to what extent different immunosuppressive regimens contribute to increased serum cholesterol levels observed in renal transplant patients after prolonged periods of immunosuppression (i.e. 3 and 5 years following kidney grafting). Therefore 2 groups of renal transplant patients were evaluated with respect to serum cholesterol 3 years (n = 103) and 5 years (n = 66) after transplantation: Group 1: prednisone (Pred)/azathioprine (Aza) [3 years (y): n = 52; 5 y: n = 49; mean prednisone dose 12 +/- 1 mg/day]; group 2: cyclosporine A (CsA) alone or in combination with Pred (3 y: n = 51; 5 y: n = 17; prednisone dose 4 +/- 2 mg/day, p < 0.001 vs group 1). The groups were similar with respect to age, sex, body mass index, time interval after transplantation, underlying kidney diseases and concomitant drug therapy. Serum cholesterol levels were persistently higher in patients of group 2 when compared to group 1 (3 years: 7.3 +/- 0.2 vs 6.7 +/- 0.2 mmol/l, p < 0.01; 5 years: 7.5 +/- 0.1 vs 6.6 +/- 0.3 mmol/l, p < 0.01) despite 75% lower daily doses of Pred (p < 0.001) in CsA treated patients (group 2). Before transplantation, patients exhibited a similar distribution of serum cholesterol levels when compared to age, sex and body mass index matched healthy subjects. In contrast 3 and 5 years following transplantation 72% of the patients had serum cholesterol levels above 6.5 mmol/l, whereas in normal subjects, 60% had serum cholesterol levels below 6.5 mmol/l.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

[Toxicity of an organic Germanium compound: deleterious consequences of a "natural remedy"].

Reports mainly from Japan, recommend germanium (Ge)-containing compounds as "anti-cancer" and "immunostimulatory" remedies. We report on a 25-tear-old woman with stage II HIV disease who consumed a total of 47 g Ge as Ge-lactate-citrate 18%. She developed severe renal insufficiency (creatinine clearance 7 ml/min/1.73 m2, proteinuria 0.28 g/d) and hepatomegaly. Biopsies revealed tubulointerstitial nephropathy with vacuolar degeneration, mainly of distal tubular epithelia, and severe liver steatosis. Tissue Ge content in kidney and liver biopsy specimens was increased 68-and 140 fold respectively. In agreement with previous reports, renal dysfunction persisted 9 months later (creatinine clearance 11 ml/min/1.73 m2).

Acute Kidney Injury↗

PubMed1992

Chronic respiratory alkalosis induces renal PTH-resistance, hyperphosphatemia and hypocalcemia in humans.

The effects of chronic respiratory alkalosis on divalent ion homeostasis have not been reported in any species. We studied four normal male subjects during a four-day control period (residence at 500 m), during six days of chronic respiratory alkalosis induced by hypobaric hypoxia (residence at 3450 m), followed by a six-day eucapnic recovery period (500 m) under metabolic balance conditions. Chronic respiratory alkalosis (delta PaCO2, -8.4 mm Hg, delta[H+] -3.2 nmol/liter) resulted in a sustained decrement in plasma ionized calcium concentration (delta[IoCa++]p, -0.10 mmol/liter, P less than 0.05) and a sustained increment in plasma phosphate concentration (delta[PO4]p, +0.14 mmol/liter, P less than 0.005) associated with increased fractional excretion of Ca++ (+0.5%, P less than 0.005), decreased phosphate clearance (-6.1 ml/min, P less than 0.025) and decreased excretion of nephrogenous cAMP (-1.5 nmol/100 ml GFR, P less than 0.0025). Urinary phosphate excretion decreased by 15.4 mmol/24 hr on day 1 of chronic respiratory alkalosis (P less than 0.0025), but returned to control values by day 6 despite hyperphosphatemia. Serum intact [PTH] did not change. Sustained hypomagnesuria (-0.8 mmol/24 hr, P less than 0.05) occurred during chronic respiratory alkalosis and was accounted for, at least in part, by decreased fractional excretion of Mg++ (-0.7%, P less than 0.05) in the absence of change in plasma magnesium concentration. Serum 1,25(OH)2D levels were unchanged by chronic respiratory alkalosis. In conclusion, the decrease in nephrogenous cAMP generation despite unchanged serum intact PTH concentration suggests that chronic respiratory alkalosis results in impaired renal responsiveness to PTH as manifested by alterations in PTH-dependent renal calcium and phosphate transport.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Renal stone disease in the 1990s: the powder keg and tinderbox theory.

Abnormal dietary habits that lead to hypercalciuria, hyperoxaluria, hypereruricosuria, and hypocitraturia do not always result in nephrolithiasis. A concept is emerging according to which, to account for renal stone formation in the face of the aforementioned biochemical disorders, one must search for underlying conditions in patients with the disease. Work carried out over the past few years and reviewed herein definitely supports this idea and includes the following processes: 1) interleukin-1 production by monocytes to augment the impact of dietary hypercalciuria; 2) disturbed activation of pyridoxine to pyridoxal 5'-phosphate to aggravate dietary hyperoxaluria; 3) abnormal intestinal transport of citrate to aggravate dietary hypocitraturia; 4) molecular abnormalities of glycoprotein inhibitors to aggravate the promotive effect of the diet on urinary crystallization; and 5) renal tubular lesions to favor particle retention and stone formation. This article reviews the most recent literature and discusses the author's "powder keg and tinderbox" theory of idiopathic calcium stone disease.

Diet↗

PubMed1992

Use of low-osmolality contrast medium does not increase prevalence of medullary sponge kidney.

To assess the prevalence of intrapapillary linear collections of contrast medium as well as of homogeneous papillary blush on excretory urograms obtained with a low-osmolality contrast medium, iohexol was used in 300 patients. Intrapapillary linear collections of contrast medium (ie, three or more linear collections of contrast material within a papilla) were found in 10 (9.5%) of the 105 patients with renal stone disease and two (1.0%) of the 195 patients without nephrolithiasis (P less than .001). These prevalences are similar to those found in a previous study with use of a high-osmolality contrast medium (sodium amidotrizoate). The difference in the prevalence of homogeneous papillary blush between stone formers and non-stone formers was nonsignificant. The authors conclude that intrapapillary linear collections of contrast medium on excretory urograms obtained with use of a low-osmolality contrast medium should be considered to have the same clinical significance as those on excretory urograms obtained with use of a high-osmolality contrast medium, that is, as indicating the presence of medullary sponge kidney.

Adolescent↗

PubMed1992

Problems concerning the bladder in renal transplantation. Prognosis--replacement possibilities.

Problems arising from the lower urinary tract in patients with a terminal renal insufficiency are usually known long before transplantation; they can even be the cause of chronic renal failure. A careful investigation of morphology and function of upper and lower urinary tract before performing renal transplantation is still of great importance. In up to a quarter of the cases pathological findings can be recorded. Whether a supravesical urinary diversion or a bladder augmentation has to be performed in case of insufficient bladder function is dependent on the urodynamic results. However, so far there are no reliable prognostic factors indicating whether or not a bladder with increased capacity due to renal transplantation reacts with normal pressure. An investigation of the lower urinary tract also has to be carried out in patients who already have a supravesical urinary derivation at the time of renal transplantation, as a possible removal always has to be taken into consideration. Survival rate following transplantation in patients with a conduit is not lower than in those with a normal bladder.

Humans↗

PubMed1992

Impact of hydration status on body composition as measured by dual energy X-ray absorptiometry in normal volunteers and patients on haemodialysis.

To evaluate the influence of hydration status on the estimation of body composition using dual-energy X-ray absorptiometry (DXA), six normal volunteers and seven patients on maintenance haemodialysis were investigated using two different DXA machines (Lunar DPX, Hologic QDR 1000/W). Normal volunteers were studied (Hologic QDR 1000/W) before and 1 h after ingestion of breakfast, lunch and dinner (drinking various amounts of liquids at each meal, 0.5-2.4 kg). Whereas bone mineral content and body fat mass did not change, lean body mass of the trunk increased as a consequence of the meals. Conversely in patients on haemodialysis (Lunar DPX), lean body mass decreased in all segments of the body as a consequence of removal of 0.9-4.4 kg of salt-containing fluid by haemodialysis (trunk 61%, legs 30%, arms 5.5% and rest of the body 3.5%), whereas bone mineral content and body fat mass remained unchanged. However, this finding(s) did not hold true in one particular patient with bilateral hip prostheses. Measurement of body composition in eight normal volunteers on the same day with both machines showed similar results for lean and fat mass, whereas bone mineral content was found to be 17% higher using the Lunar DPX. In summary, in centres where both machines are available, follow-up of one individual patient should always be performed using the same equipment. In addition, hydration status and food intake must be taken into account when repetitive measurements of lean body mass are performed in the same patient.

Absorptiometry, Photon↗

PubMed1992

[Acute hemodynamic effects of SIN-1 and isosorbide dinitrate in stable left ventricular failure: a comparative double-blind, cross-over study].

The acute hemodynamic effects of intravenous SIN-1 (1 mg) and sublingual isosorbide dinitrate (5 mg) were investigated in 12 patients (8 men and 4 women) between 38 and 80 years of age and suffering from stable chronic left ventricular failure (NYHA Classes III-IV) secondary to ischemic myocardiopathy (n = 5), hypertensive disease (n = 2) or idiopathic disorder (n = 5) corresponding to the following hemodynamic inclusion criteria: stable condition, cardiac index > or = 2 l/min/m2, mean capillary pressure > or = 18 mmHg and < or = 28 mmHg. Previous treatments were continued with the exception of vasodilators and diuretics which were stopped 24 hours earlier. The hemodynamic data from this cross-over, double-blind double-dummy trial were collected for two 60-hour periods separated by a washout period of 120 minutes. Simultaneously, venous samples were taken for the assay of plasma levels of SIN-1. The heart rate, cardiac output, pulmonary artery resistance and blood pressure were not affected by either SIN-1 or isosorbide dinitrate. An obvious reduction (> 15% of the basal value) in the mean capillary pressure, pulmonary artery pressure and mean right atrial pressure was observed in 10 subjects after SIN-1 and in 7 patients isosorbide dinitrate. A statistically non-significant trend towards a more marked effect (number of patients responding and maximum amplitude of pressure reduction) which occurred more rapidly and lasted longer was observed after SIN-1. Analysis of the relationship between the pharmacodynamics and pharmacokinetics of SIN-1 suggests that an active metabolites is involved. No adverse effects were reported.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Impact of dialysis modality on body composition in patients with end-stage renal disease.

Loss of muscle mass and altered body fat distribution (i.e. increased central fat stores in the presence of normal peripheral fat stores) have been reported in patients on hemodialysis (HD), when compared to normal volunteers. Whether treatment of end-stage renal disease (ESRD) with continuous ambulatory peritoneal dialysis (CAPD) would alter body composition in a different manner than HD is unknown. To answer this question, two groups (n = 11 each) of male patients with ESRD (matched for age, residual renal function, body weight and body height as well as physical activity) were studied. Muscle mass and body fat distribution were assessed using computed tomography. Mid-thigh muscle area, peripheral and central fat stores were similar between the two groups of dialysis patients. In both patient groups muscle mass and fat stores were independent of duration of dialysis, age, daily protein intake and residual renal function. In CAPD-patients mid-thigh muscle area was correlated with plasma albumin (r = 0.56, p < 0.05), while serum cholesterol level was correlated with mediastinal fat area (r = 0.81, p < 0.01). The present results indicate that both treatment modalities of ESRD (HD vs CAPD) result in similar changes of body composition. Despite continuous glucose loading in CAPD-patients, neither central nor peripheral fat stores are increased in these subjects compared with HD treated patients.

Adipose Tissue↗

PubMed1992

[Hyper- and hypocalcemia: diagnosis and treatment].

The establishment of an abnormal calcemia first requires confirmation by a second measurement that should then be interpreted in relation to albuminemia. Should the abnormality be confirmed, measurement of intact parathormone in serum can help distinguishing between a parathyroid or non parathyroid source of origin. In presence of plasma calcium level lower than or equal to 2.9 mmol/L regular monitoring should be provided and aggravating factors such as thiazide diuretics, dehydration or high calcium intake, avoided. If plasma calcium is greater than 3 mmol/L the patient should first be rehydrated. In case of primary hyperparathyroidism, parathyroidectomy is the only effective treatment. In neoplastic hypercalcemia bisphosphonates are the first choice treatment when antitumoral therapy turns out to be insufficient. Hypocalcemia can be effectively corrected by calcium and vitamin D derivatives.

Calcium↗

PubMed1992

[Respective role of the size, location and composition of the calculus as determinants of therapeutic success after extracorporeal shock wave lithotripsy in renal lithiasis].

We evaluated the respective role of size, location and composition of renal stones as determinants of the outcome of extracorporeal shock wave lithotripsy (ESWL). The analysis of the chemical composition and of the morphology of the fragments eliminated by hundred patients who underwent ESWL has been made by X-rays diffraction. Results showed that the larger the stone, the higher the risk of having to perform an extra intervention (additional sessions of ESWL, percutaneous nephrostolithotomy, nephrolitholapaxy) or of finding residual fragments at the three month check-point. In addition, the location of the stone in a calice, especially a lower calice, strongly predisposes to incomplete elimination of the fragments. Finally, two types of stones appear to lessen the probability of success of ESWL: those of struvite and those of cystine. Indeed, out of eleven ESWL performed on struvite stones (pure or mixed), two had to be completed by percutaneous nephrolitholapaxy and even one by a nephrectomy because of superinfection. Out of the four patients with cystine stones, two had to be treated by additional percutaneous nephrolitholapaxy because of inadequate fragmentation after ESWL. However, for the remaining types of stones (pure or mixed) chemical composition seems to be less important than size or location.

Cystine↗

PubMed1992

[Biopsy of the testis].

Biopsy of the testis has been considered for a long time and continues to be an acknowledged method of examination in the framework of investigation of male infertility. A classical indication for this is the repeated statement of azoospermia with normal size of the testes. On part of the spermogram, the indication for testicular biopsy is however not limited just to azoospermia. On the other hand, one can do without a biopsy when the size of the testes is less than 2.5 cm, as almost certainly a pronounced testicular atrophy which cannot be influenced will be present. Diagnosis of testicular precancerous conditions represents a more recent indication for biopsy of the testis which will probably gain more importance in the future. Anamnestic and clinical informations and above all the correct fixation and treatment of the specimen are an absolute prerequisite for the perfect interpretation of the bioptic picture.

Atrophy↗

PubMed1991

[Physiopathology, etiology and medical treatment of non-calcium lithiasis].

Under the term "non-calcium nephrolithiasis", three types of renal stone formation are considered. (1) Infected nephrolithiasis, which is due to bacteriological ureolysis. Its treatment includes lowering of oversaturation by antibiotics, urease inhibition and/or acidification of the urine; lowering of crystallization by eradicating concomitant infections caused by non-ureolytic organisms; prevention of crystal adherence by exogenous glycosaminoglycans, and prevention of bacterial adherence by glycolipids. (2) Uric acid lithiasis is defined on physico-chemical and physiopathological grounds. Medical treatment consists of increasing water intake, reducing puric acid intake, alkalinizing the urine inhibiting xanthine-oxidase. (3) Cystinuria is described as a nephrolithogenic proximal tubulopathy. Medical treatment includes reduction of urinary cystine concentration by a strong increase of water intake; reduction of urinary cystine excretion by diet and increase of cystine solubility by urinary alkalinization or administration of some thiol compounds.

Cystinuria↗