Biomedical subjects

T Meschi

Publications and source records attributed to T Meschi.

13 recordsLinked to original sources

PubMed1999

Essential arterial hypertension and stone disease.

BACKGROUND: Cross-sectional studies have shown that nephrolithiasis is more frequently found in hypertensive patients than in normotensive subjects, but the pathogenic link between hypertension and stone disease is still not clear. METHODS: Between 1984 and 1991, we studied the baseline stone risk profile, including supersaturation of lithogenic salts, in 132 patients with stable essential hypertension (diastolic blood pressure of more than 95 mm Hg) without stone disease and 135 normotensive subjects (diastolic blood pressure less than 85 mm Hg) without stone disease who were matched for age and sex (controls). Subsequently, both controls and hypertensives were followed up for at least five years to check on the eventual formation of kidney stones. RESULTS: Baseline urine levels in hypertensive males were different from that of normotensive males with regards to calcium (263 vs. 199 mg/day), magnesium (100 vs. 85 mg/day), uric acid (707 vs. 586 mg/day), and oxalate (34.8 vs. 26.5 mg/day). Moreover, the urine of hypertensive males was more supersaturated for calcium oxalate (8.9 vs. 6.1) and calcium phosphate (1.39 vs. 0.74). Baseline urine levels in hypertensive females were different from that of normotensive females with regards to calcium (212 vs. 154 mg/day), phosphorus (696 vs. 614 mg/day), and oxalate (26.2 vs. 21.7 mg/day), and the urine of hypertensive females was more supersaturated for calcium oxalate (7.1 vs. 4.8). These urinary alterations were only partially dependent on the greater body mass index in hypertensive patients. During the follow-up, 19 out of 132 hypertensive patients and 4 out of 135 normotensive patients had stone episodes (14.3 vs. 2.9%, chi-square 11.07, P = 0.001; odds ratio 5.5, 95% CI, 1.82 to 16.66). Of the 19 stone-former hypertensive patients, 12 formed calcium calculi, 5 formed uric acid calculi, and 2 formed nondetermined calculi. Of the urinary factors for lithogenous risk, those with the greatest predictive value were supersaturation of calcium oxalate for calcium calculi and uric acid supersaturation for uric acid calculi. CONCLUSIONS: A significant percentage of hypertensive subjects has a greater risk of renal stone formation, especially when hypertension is associated with excessive body weight. Higher oxaluria and calciuria as well as supersaturation of calcium oxalate and uric acid appear to be the most important factors. Excessive weight and consumption of salt and animal proteins may also play an important role.

Adult↗

PubMed1999

Relationship between supersaturation and calcium oxalate crystallization in normals and idiopathic calcium oxalate stone formers.

BACKGROUND: In an earlier study on recurrent CaOx stone formers with no detectable abnormalities, we found that the urine of these subjects had a lower tolerance to oxalate load than controls and that the removal of urinary macromolecules with a molecular weight greater than 10,000 D improved their tolerance to oxalate. METHODS: The effects on CaOx crystallization of reduced urinary supersaturation of calcium oxalate (CaOx), induced by night water load, were studied in 12 normal males and in 15 male OxCa stone formers who were free from urinary metabolic abnormalities. The effect of the macromolecules, purified and retrieved from the natural and diluted urine, were analyzed in a metastable solution of CaOx. RESULTS: The water load caused an increase in urine volume (from 307 +/- 111 to 572 +/- 322 ml/8 hr, P = 0.014 in normal subjects, and from 266 +/- 92 to 518 +/- 208 ml/8 hr, P = 0.001 in the stone formers) and a concomitant reduction of the relative CaOx supersaturation (from 8.7 +/- 2.5 to 5.1 +/- 2.5 ml/8 hr, P = 0.001 in normal subjects, and from 10.4 +/- 3.5 to 5.0 +/- 2.7 ml/8 hr, P = 0.001 in the stone formers). The decrease in CaOx supersaturation was accompanied by an increase of the permissible increment in oxalate, both in normal subjects (from 43.8 +/- 10.1 to 67.2 +/- 30. 3 mg/liter, P = 0.018) and in the stone formers (from 25.7 +/- 9.4 to 43.7 +/- 17.1 mg/liter, P = 0.0001), without any significant variations of the upper limit of metastability for CaOx (from 21.6 +/- 5.3 to 20.5 +/- 4.2 mg/liter in normal subjects, and from 18.7 +/- 4.5 to 17.1 +/- 3.7 mg/liter in the stone formers). The inhibitory effect of urinary macromolecules with molecular weight greater than 10,000 Daltons did not undergo any change when the latter were recovered from concentrated or diluted urine, either in normal subjects or in the stone formers. CONCLUSIONS: Reduced CaOx supersaturation by means of water load has a protective effect with regards to CaOx crystallization in subjects who do not present any of the common urinary stone risk factors.

Adult↗

PubMed1999

Urine volume: stone risk factor and preventive measure.

BACKGROUND: A high fluid intake is the oldest existing treatment for kidney stones, and, up until a few decades ago, it was the only preventive measure at the physician's disposal for stone recurrences. METHODS: Using the data available in literature and partly unpublished personal research, we examine the role of urine volume as a stone risk factor, its impact on calcium crystallization mechanisms and its real importance as a means of prevention. RESULTS: To sum up, the most important findings are: (1) a low urine volume must be considered as a real risk factor, both as regards the onset of renal calculi and stone relapses; (2) an increase in urine volume induced by a high water intake produces favourable effects on the crystallization of calcium oxalate and does not reduce the activity of natural inhibitors; (3) a sufficiently high intake of water and probably other fluids such as coffee, tea, beer and wine has a preventive effect on nephrolithiasis and its recurrence, and (4) the role of fruit juice is still to be defined. CONCLUSIONS: A high intake of fluids, especially water, is still the most powerful and certainly the most economical means of prevention of nephrolithiasis, and it is often not used to advantage by stone formers.

Calcium↗

PubMed1996

Urinary volume, water and recurrences in idiopathic calcium nephrolithiasis: a 5-year randomized prospective study.

PURPOSE: We define the role of urine volume as a stone risk factor in idiopathic calcium stone disease and test the actual preventive effectiveness of a high water intake. MATERIALS AND METHODS: We studied 101 controls and 199 patients from the first idiopathic calcium stone episode. After a baseline study period the stone formers were divided by randomization into 2 groups (1 and 2) and they were followed prospectively for 5 years. Followup in group 1 only involved a high intake of water without any dietetic change, while followup in group 2 did not involve any treatment. Each year clinical, laboratory and radiological evaluation was obtained to determine urinary stone risk profile (including relative supersaturations of calcium oxalate, brushite and uric acid by Equil 2), recurrence rate and mean time to relapse. RESULTS: The original urine volume was lower in male and female stone formers compared to controls (men with calcium oxalate stones 1,057 +/- 238 ml./24 hours versus normal men 1,401 +/- 562 ml./24 hours, p < 0.0001 and women calcium oxalate stones 990 +/- 230 ml./24 hours versus normal women 1,239 +/- 440 ml./24 hours, p < 0.001). During followup recurrences were noted within 5 years in 12 of 99 group 1 patients and in 27 of 100 group 2 patients (p = 0.008). The average interval for recurrences was 38.7 +/- 13.2 months in group 1 and 25.1 +/- 16.4 months in group 2 (p = 0.016). The relative supersaturations for calcium oxalate, brushite and uric acid were much greater in baseline urine of the stone patients in both groups compared to controls. During followup, baseline values decreased sharply only in group 1. Finally the baseline urine in patients with recurrences was characterized by a higher calcium excretion compared to urine of the patients without recurrences in both groups. CONCLUSIONS: We conclude that urine volume is a real stone risk factor in nephrolithiasis and that a large intake of water is the initial therapy for prevention of stone recurrences. In cases of hypercalciuria it is suitable to prescribe adjuvant specific diets or drug therapy.

Adult↗

PubMed1995

Effects of urinary macromolecules on the nucleation of calcium oxalate in idiopathic stone formers and healthy controls.

Urinary macromolecules have attracted great interest because of their possible role as both promoters and inhibitors of calcium oxalate (CaOx) crystallization and it remains unclear whether there is any difference, in their nucleating activity, between stone formers and controls. We selected 9 male idiopathic CaOx stone formers whose 24-h urines presented no evidence of common urinary stone risk factors such as hypercalciuria, hyperoxaluria, hyperuricosuria, hypocitraturia, hypomagnesiuria or low glycosaminoglycans excretion and 12 male controls (matched for age and body weight) whose 24-h urines did not differ from those of stone formers. The study of urinary CaOx nucleation was made in freshly voided overnight urines whose biochemical composition was almost identical in the two groups. In filtered (0.22 micron) and ultrafiltered (10 kDa) urine we performed an oxalate tolerance test to determine the permissible increment of oxalate, the oxalate level for nucleation and the permissible increment of CaOx relative supersaturation (CaOx RS). In filtered urine from stone formers the permissible increment of oxalate was lower than controls (30 +/- 10.2 vs. 46.7 +/- 9.7 mg/l, P = 0.001), the oxalate level for nucleation was lower (64.4 +/- 14.2 vs. 79.5 +/- 15.6 mg/l, P = 0.035) and the permissible increment of CaOx RS was also lower (9.71 +/- 2.59 vs. 13.39 +/- 3.62, P = 0.018). In ultrafiltered urine these differences disappeared because the removal of macromolecules in stone formers significantly enhanced the oxalate-tolerance values. The difference between the change of the oxalate permissible increment of filtered and ultrafiltered urine allowed a distinction to be made between stone formers and controls that was not feasible in other ways (7.6 +/- 5.3 vs. 3.3 +/- 5.9 mg/l, P < 0.0001). The study suggests that, in idiopathic CaOx stone formers free from common urinary risk factors of CaOx crystallization, there is an increased tendency for CaOx nucleation in urine, which is mediated by macromolecular components.

Adult↗

PubMed1994

Nifedipine and methylprednisolone in facilitating ureteral stone passage: a randomized, double-blind, placebo-controlled study.

Expulsive medical therapy of ureteral stones is not well established. To test the efficacy of a calcium antagonist (nifedipine) associated with a corticosteroid (methylprednisolone) in facilitating ureteral stone passage, we studied 86 patients with a unilateral ureteral radiopaque stone not larger than 15 mm. in maximum diameter, confirmed in each case by drop excretory urography. Patients were randomly treated for a maximum of 45 days under double-blind conditions with 16 mg. methylprednisolone plus 40 mg. nifedipine daily (group 1-13 women and 30 men, mean age 45 +/- 14 years, standard deviation) and with 16 mg. methylprednisolone plus placebo daily (group 2-18 women and 25 men, mean age 43 +/- 14 years). All patients also received 2 l. of low mineral content water daily. The average maximum diameter of the stones was 6.7 +/- 3.0 mm. in group 1 and 6.8 +/- 2.9 mm. in group 2 (not significant). Partial ureteral obstruction was present in approximately half of the patients in both groups. Four patients in group 1 and 6 in group 2 dropped out of the study. In group 1, 34 patients had successful results (stone passage without surgical manipulation) and 5 failed (success rate 87%), compared to 24 and 13, respectively, in group 2 (success rate 65%). This difference was significant (p = 0.021, Fisher's exact test). No difference was present in the maximum stone diameter among the successful cases in groups 1 and 2 (6.4 +/- 2.8 and 5.3 +/- 2.2 mm., respectively, not significant). In both groups the maximum diameter of the stone was larger in the failed than in the successful cases (group 1-10.4 +/- 3.0 versus 6.4 +/- 2.8 mm., p = 0.005, and group 2-9.3 +/- 2.5 versus 5.3 +/- 2.2 mm., p = 0.0001). In group 1 the mean interval for stone passage in the successful cases was 11.2 +/- 7.5 days, compared to 16.4 +/- 11.0 days in group 2 (p = 0.036, Student's t test). We conclude that nifedipine associated with methylprednisolone is effective in facilitating ureteral stone passage.

Adolescent↗

PubMed1993

Hot occupation and nephrolithiasis.

We investigated the prevalence of stone disease and urinary stone risk factors in machinists chronically exposed to a hot environment and massive sweating, without interference of nephrotoxic metals or other lithogenic compounds. The study was performed at a glass plant and exposure to heat stress was estimated by the Wet Bulb Globe Temperature climatic index. The prevalence of nephrolithiasis on the entire population of the machinists was 8.5% (20 of 236), while the prevalence on the controls working in normal temperature was 2.4% (4 of 165) (p = 0.03). A high incidence (38.8%) of uric acid stones was present in the workers exposed to heat stress. Among the urinary stone risk indexes determined for 3 days during the 8-hour work shift on a randomly selected sample of 21 workers exposed and 21 workers not exposed to heat stress without any evidence of stone disease significant differences were found in uric acid concentration (722 +/- 195 versus 482 +/- 184 mg./l., p < 0.001), specific gravity (1,026 +/- 4 versus 1,021 +/- 6, p < 0.005) and pH (5.31 +/- 0.28 versus 5.64 +/- 0.54, p < 0.02), respectively. Thus, high uric acid relative supersaturation was present during occupation in hot temperatures (8.67 +/- 3.49) compared to occupation in normal temperatures (4.15 +/- 2.7) (p < 0.001). This study confirms that chronic dehydration represents a real lithogenic risk factor, mainly for uric acid stones, and adequate fluid intake is recommended during hot occupations.

Adult↗

PubMed1993

Randomized prospective study of a nonthiazide diuretic, indapamide, in preventing calcium stone recurrences.

We examined the biochemical changes and the efficacy of indapamide in the prevention of calcium stone recurrences. Seventy-five patients with calcium nephrolithiasis and hypercalciuria were randomly assigned to three different therapies: diet and fluid (group A), diet and fluid plus indapamide 2.5 mg/day (group B), and diet and fluid plus indapamide 2.5 mg/day plus allopurinol 300 mg/day (group C). Before treatment and after 6, 12, 24, and 36 months of therapy, we evaluated blood pressure, serum and urine risk parameters (including relative supersaturations of calcium oxalate, calcium phosphate and uric acid), stone rate, and the proportion of calculi-free patients. During the 3 years of treatment, urinary calcium greatly decreased in groups B and C, dropping to 50% of the pretreatment values; urinary oxalate also significantly declined in group B (-24%) and group C (-27%). Relative supersaturations of calcium oxalate and calcium phosphate decreased to the same extent in groups B and C (about one-half of the pretreatment value), and relative supersaturation of uric acid was particularly reduced in group C (-65% of the pretreatment value). The stone rate improved in all three groups (p < 0.005), but using actuarial analysis in the evaluation of calculi-free patients, indapamide, and indapamide plus allopurinol groups were found to have a significantly more favorable effect than diet and fluid treatment (p < 0.02), without any difference between the two drug groups. Because indapamide has fewer side effects than thiazide diuretics, we conclude that indapamide could be an interesting alternative to thiazides in the prevention of calcium stones in hypercalciuric patients.

Adult↗

PubMed1991

Vertebral mineral content in diet-dependent and diet-independent hypercalciuria.

The vertebral mineral content was measured using dual photon absorptiometry in 41 calcium stone patients with idiopathic hypercalciuria. These patients had been previously divided into 2 groups (diet-dependent and diet-independent hypercalciuria) during a low sodium and low calcium diet. In some of the patients (11 with diet-dependent and 11 with diet-independent hypercalciuria) the vertebral mineral content was evaluated in relation to serum ionized calcium, intact parathyroid hormone, alkaline phosphatase and osteocalcin determined after a low sodium and low calcium diet. The vertebral mineral content, expressed as Z-VMD, was normal in diet-dependent and lower in diet-independent hypercalciuric stone patients (-0.30 +/- 1.19 versus -0.26 +/- 1.18, p less than 0.02). In 7 of 21 patients (33.3%) the vertebral mineral content was less than 2 standard deviations of the normal value, indicating a true involvement in bone metabolism. Serum intact parathyroid hormone and osteocalcin levels were not different from the controls in both groups, while alkaline phosphatase activity and ionized calcium were higher in diet-independent hypercalciuric patients. Serum ionized calcium was negatively correlated with bone vertebral density. The results suggest that an increased bone turnover may be a primary event in causing hypercalciuria in calcium stone patients unable to decrease urinary calcium to less than the calcium intake.

Absorptiometry, Photon↗

PubMed1990

[Cystinuria: description of a simple method of determination and our 5-year clinical experience].

Ion exchange chromatography is the best method for the determination of cysteine in urine, but it requires an expensive apparatus, specialized technicians and a long time. The major colorimetric procedure is the nitroprusside color reaction first described by Brand, but it involves the reaction with toxic cyanide reagent. Moreover commercial stick are not available. We have experienced a colorimetric procedure in which the sulfhydryl group of cystine reduces phosphotungstic acid to tungstic blue, which is determined photometrically. This procedure avoids the use of cyanide. We used this screening test during 5 years of ambulatory evaluation of nephrolithiasis and we found these results: urine cystine 191 controls: 87 +/- 57 mg/day, 870 stone oxalate and uric acid patients: 99 +/- 57 mg/day, 11 stone cystine patients: 479 +/- 379 mg/day (p 0.001). A close correlation was found in stone cystine patients between our data obtained in the same sample with ion exchange chromatography. We conclude that this inexpensive and simple method can be recommended as a screening test for cystinuria.

Adolescent↗

PubMedDate not supplied

Acute polyradiculoneuropathy occurring after hymenoptera stings: a clinical case study.

Hymenoptera stings may be responsible for both local and systemic reactions; these can be immediate or delayed, depending on the time between the sting and the development of signs or symptoms. Delayed clinical reactions have been reported, although unusual, due to serum sickness and/or affecting organs or systems generally not involved in the immediate reaction, such as heart, kidneys, central and peripheral nervous systems. This paper describes the clinical and immunological findings in a 51-year-old subject, who, after two stings of paper wasps, the second one after the third venom immunotherapy (VIT) injection, presented immediate large local and systemic allergic reactions which quickly improved after e.v. methylprednisolone administration. About 40 hours later, he developed acute polyradiculoneuropathy with muscle weakness, paresthesia, difficulties in standing up and walking. Skin tests and specific IgE determination showed allergy to paper wasp. The activation, by wasp venom, of peripheral blood mononuclear cells in primary culture, evaluated by tritiated thymidine incorporation proliferation assay, showed an important hypersensitivity to wasp venom. Therefore our results suggest the hypothesis that the polyradiculoneuritis causative etiopathogenetic mechanism might be a delayed immunological response to wasp antigens followed by an allergy-triggered autoimmune reaction, as previously suggested by other authors; they found lymphocytic infiltrates in demyelinization areas and at perivascular levels, by histologic examination of autoptical and bioptical material of patients with nervous system lesions after hymenoptera stings.

Acute Disease↗

PubMedDate not supplied

[Post-acute long stay and extensive rehabilitation: study of the first year of work at a long stay university hospital unit].

Long stay is a new type of hospital admission geared to internal medicine patients requiring long-term stays in hospital and prolonged treatment for the purposes of stabilization or clinical rehabilitation. Given the lack of specific experience, we monitored the progress of a Long-Stay Unit with the aim to estimate the clinical and organizational impact. We studied 263 patients (59.3% females, 40.7% males; mean age 76.3 +/- 11.5 years, 42.2% all in their late eighties) coming from medical wards (75%) and from surgical wards (25%). The clinical complexity was prospectively estimated by a form divided into 3 sections: the first part was filled out at the time of transfer, the second part at set intervals throughout the period and the third at the end of the stay. Mean length of stay for medical patients was 33.2 days, for surgical patients 28.6 days (NS). Main transfer diagnosis: 50% of the patients fell into two diagnostic groups: malignant neoplasm (33.1%) and cerebral ictus (17.5%). Some data evidenced remarkable clinical complexity: 93.9% of the patients had one or more secondary diagnoses; when initially admitted 89.4% already presented with complications or serious outcomes; while in the Long-Stay Unit 83.3% required medical treatment and extensive nursing care; 87.1% had further major complications; 56.3% was totally dependent; 42.6% was totally bedridden and 35.4% died. In conclusion, the majority of long-stay patients in a medium-to-large polyclinic hospital present with several concomitant diseases, with extremely invalidating complaints, characterized over the short-to-mid term by serious clinical complications. They require a great deal of competent medical/nursing care as well as highly qualified internal medicine specialists.

Acute Disease↗

PubMedDate not supplied

[Artificial nutrition in acute renal failure].

Artificial nutrition in course of acute renal failure (ARF) is reviewed, on the basis of recent concepts on epidemiology and prognosis of the syndrome in critically ill patients. The relationships between nutritional status and ARF are evaluated, analyzing the possible role of nutritional status alterations as comorbidities and complications; pathogenetic mechanisms and consequences of hypercatabolism are described, with special regard to the peculiar metabolic derangements which are the hallmark of ARF. The effects of artificial nutrition on mortality and morbility in ARF are illustrated, along with quantitative and qualitative aspects of nutritional support (energy and protein needs, trace elements, vitamins etc). A rational approach to nutritional management of ARF patients is proposed, stressing the potential role of enteral nutrition, as well as the need for a full integration between nutritional support and renal replacement therapies.

Acute Kidney Injury↗