The efficacy of dietary intervention on urinary risk factors for stone formation in recurrent calcium oxalate stone patients

PURPOSE: Nutrition is suggested to be the major environmental risk factor in idiopathic calcium oxalate stone disease. The study was designed to evaluate the effect of dietary intervention on urinary risk factors for recurrence in calcium oxalate stone formers. MATERIALS AND METHODS: A total of 76 men and 31 women with idiopathic calcium oxalate stone disease collected 24-hour urine on their habitual, self-selected diets and after 7 days on a balanced standardized diet according to the recommendations for calcium oxalate stone formers. RESULTS: On the usual diet, a urine volume of less than 2.0 l per 24 hours was present in 57.9%, hypercalciuria in 25.2%, hypomagnesuria in 18.7%, hyperoxaluria in 14.0%, hyperuricosuria in 41.3% and hypocitraturia in 57.0% of patients. The frequency of metabolic abnormalities and the risk of calcium oxalate stone formation decreased significantly on the ingestion of the balanced diet, due to the significant increase in urinary volume, pH and citrate excretion and the significant decrease in urinary calcium and uric acid excretion. No change occurred in urinary oxalate and magnesium excretion. CONCLUSIONS: The evaluation of urinary risk profiles of the patients on their usual dietary habits revealed a high risk for calcium oxalate stone formation. A low fluid intake and an increased intake of protein and alcohol were identified as the most important dietary risk factors. The shift to a nutritionally balanced diet according to the recommendations for calcium oxalate stone formers significantly reduced the stone forming potential.     

Modular kinetic analysis of the adenine nucleotide translocator-mediated effects of palmitoyl-CoA on the oxidative phosphorylation in isolated rat liver mitochondria

To test whether long-chain fatty acyl-CoA esters link obesity with type 2 diabetes through inhibition of the mitochondrial adenine nucleotide translocator, we applied a system-biology approach, dual modular kinetic analysis, with mitochondrial membrane potential (Deltapsi) and the fraction of matrix ATP as intermediates. We found that 5 mumol/l palmitoyl-CoA inhibited adenine nucleotide translocator, without direct effect on other components of oxidative phosphorylation. Indirect effects depended on how oxidative phosphorylation was regulated. When the electron donor and phosphate acceptor were in excess, and the mitochondrial "work" flux was allowed to vary, palmitoyl-CoA decreased phosphorylation flux by 38% and the fraction of ATP in the medium by 39%. Deltapsi increased by 15 mV, and the fraction of matrix ATP increased by 46%. Palmitoyl-CoA had a stronger effect when the flux through the mitochondrial electron transfer chain was maintained constant: Deltapsi increased by 27 mV, and the fraction of matrix ATP increased 2.6 times. When oxidative phosphorylation flux was kept constant by adjusting the rate using hexokinase, Deltapsi and the fraction of ATP were not affected. Palmitoyl-CoA increased the extramitochondrial AMP concentration significantly. The effects of palmitoyl-CoA in our model system support the proposed mechanism linking obesity and type 2 diabetes through an effect on adenine nucleotide translocator.     

Back to basics in diagnosing diabetic polyneuropathy with the tuning fork!

OBJECTIVE: Several national and international scoring systems are used to diagnose diabetic polyneuropathy (PNP). The variety in these scores and the lack of data on validity and predictive value has led to a comparison and validation of the scores with clinical standards for PNP to determine the most powerful measurement for screening. RESEARCH DESIGN AND METHODS: Three matched groups were selected: 24 diabetic patients with neuropathic foot ulcers, 24 diabetic patients without PNP or ulcers, and 21 control subjects without diabetes. In all participants the scores from the International Consensus on the Diabetic Foot (ICDF) and the Dutch Nederlandse Diabetes Federatie-Centraal Beleids Orgaan (NDF/CBO) were tested. The Diabetic Neuropathy Symptom score, the Diabetic Neuropathy Examination score, Heart Rate Variability, the Nerve Conduction Sum score, and a San Antonio Consensus sum score were obtained as clinical standards. Reproducibility was tested in a separate study (13 patients). RESULTS: The construct validity and discriminative power of the ICDF and NDF/CBO scores were comparable, although monofilaments (NDF/CBO) scored lower. The predictive value was good for all scores, with the best results being obtained for the tuning fork (NDF/CBO). Reproducibility of the NDF/CBO scores (monofilaments and tuning fork) was high. CONCLUSIONS: The characteristics of the scores of tests recommended by ICDF and NDF/CBO are comparable. The single use of the 128-Hz tuning fork produces results similar to the extended scores of the ICDF and much better than those of monofilaments on validation and for predictive value. For screening we therefore advise the use of the tuning fork alone.     

Fast neutron therapy for locally advanced sarcomas

In this paper preliminary results of 22 patients irradiated with d + T fast neutrons for advanced sarcomas are described. The results were disappointing as only 8 patients achieved local tumor control and 6 patients had severe radiation damage. These results are compared with data described by other authors.     

An evaluation of methods to decrease the availability of inorganic sulphate for sulphate conjugation in the rat in vivo

The concentration of inorganic sulphate in serum of the rat (about 0.9 mM) could be lowered in the following three different ways. (1) Oral administration of sodium chloride (8 mmol/kg) decreased serum sulphate within 2 hr to 0.5 mM. Eight hours after administration serum sulphate had returned to the control level. (2) Feeding of a low-protein diet (8 per cent casein, without supplements of sulphur-containing amino acids or inorganic sulphate salts) reduced urinary sulphate excretion in 2 days to 10 per cent of control. Concomitantly, serum sulphate was decreased to half the control level. (3) Paracetamol (1.0 or 1.5 mmol/kg, orally), a substrate of sulphation, reduced serum sulphate within 3 hr to 30 per cent of control. Eight hours after administration the sulphate concentration tended to rise again. Fasting initially increased serum sulphate; after 3 days of fasting still considerable amounts of inorganic sulphate were excreted in urine (50–70 per cent of control). Even after 3 days serum sulphate was not yet significantly decreased below control. Lowering of the serum sulphate concentration results in a decreased availability of inorganic sulphate.Sulphation of a high dose of phenol (266 μmol/kg) was decreased at a serum concentration of sulphate of 0.3 mM, presumably because sulphate was depleted by the high dose of phenol. Feeding the low-protein diet, however, caused no decrease in sulphation at a tracer dose of [¹⁴C]-phenol (1.25 μmol/kg), while paracetamol pretreatment did cause a decrease in the fraction of the dose that became sulphated, probably because remaining unconjugated paracetamol competed with phenol for sulphation; the tracer dose of [¹⁴C]-phenol did not further deplete sulphate. The findings are discussed in relation to implications for the toxicity of many xenobiotics that are eliminated as sulphate conjugates.     

MR imaging of the wrist: comparison between 1.5- and 3-T MR imaging--preliminary experience

Institutional review board approval and informed consent were obtained from 25 healthy volunteers and 15 consecutive patients with chronic wrist pain or suspected carpal mass, and 1.5- and 3-T magnetic resonance (MR) imaging of the wrist was prospectively performed with comparable sequence parameters and surface coils of the same geometric design. Imaging protocols at both field strengths included a T1-weighted spin-echo sequence, two intermediate-weighted fast SE sequences with different echo times and with and without fat saturation, and a three-dimensional fast field-echo sequence. The contrast-to-noise ratio (CNR) between muscle and bone and between bone and cartilage was calculated for both field strengths. The visibility of various anatomic structures, including the triangular fibrocartilage complex, carpal ligaments, nerves, and cartilage, was analyzed with a four-point grading scale. CNRs were significantly higher on 3-T MR images than on 1.5-T MR images (P < .001; analysis of variance) for all sequences. Visibility of the triangular fibrocartilage complex and intercarpal ligaments and cartilage was significantly better on 3-T MR images than on 1.5-T MR images (paired sign test).     

Parallel imaging at high field strength: synergies and joint potential

MRI faces fundamental limitations in terms of sensitivity and speed. These limitations can be effectively tackled by the transition to higher field strengths and parallel imaging technology. Owing to largely independent physics, the two approaches can be readily combined. Considering the specific advantages and disadvantages of high field strength and parallel imaging, it is found that the combination is particularly synergistic. In the joint approach, the two concepts play different roles. Higher field strength acts as a source of higher baseline signal-to-noise ratio (SNR), while parallelization acts as a means of converting added SNR into a variety of alternative benefits. This interplay holds promise for a broad range of clinical applications, as recently illustrated by several imaging studies at 3 T. As a consequence, clinical MRI at 3 T and higher is expected to rely more on parallel acquisition than at lower field strength. The specific synergy with parallel imaging may even make 3 T the field strength of choice for a range of exams that conventionally work best at 1.5 T or less.