Category: Disease - Part 3

The amazing advances in molecular genetics have also in­volved hypercalciuria, and at least three candidate genes were shown to arbour mutations leading to altered calcium excretion. The chloride channel 5 (ClC-5), the calcium sensing receptor and the paracellin-1 are proteins encoded by corresponding genes, whose mutations causing either loss or gain of function, lead to hypercalciuric syndromes (Table II). Transfection or gene-disruption studies with these genes not only contribute to clarify mechanisms of the underlying diseases, but also help to understand the pathophysiology of idiopathic hypercalciurias. Recent reports have addressed the issue of treatment of ge­netic hypercalciurias, namely, in the course of Dent’s syndrome and familial hypocalcemic hypercalciuria. The mechanism leading to hypercalciuria in Dent’s syndromes is as yet not fully elucidated, in that both intestinal hyperab- sorption and renal leak could contribute. Chlorthalidone, but not amiloride, was shown to reduce both calcium excretion and calcium oxalate and calcium phosphate supersaturation in Dent’s syndrome, yielding similar results as in patients with id- iopathic hypercalciuria. These results led authors to con­clude that the hypocalciuric response to thiazides indicates that inactivation of the ClC-5 does not impair calcium transport in the distal convoluted tubule and that thiazides should be effec­tive in reducing the risk of kidney stone recurrence in these pa­tients. cialis professional canadian drugstore

Different approaches were tried in patients with CaR mutations with gain of function. These patients may present with hypocal- cemia of various severity, some of them presenting with major clinical signs of hypocalcemia. The classical treatment with ac­tive vitamin D derivatives, while relieving hypocalcemic symp­toms, induced significant increases in calcium excretion with an attendant risk of nephrocalcinosis. More recently, synthetic human PTH-(1-34) was shown to provide a safe and effective alternative to calcitriol therapy, able to maintain normal serum calcium levels without hypercalciuria. Similar encouraging results have been reported in two such patients by using hy- drochlorothiazide (1 mg/kg), which reduced urinary calcium ex­cretion and maintained serum calcium concentrations near the lower limit of normal, allowing the vitamin D doses to be re­duced, while alleviating symptoms. Finally, magnesium salts and thiazides were used to treat pa­tients with FHHNC (see Table II) caused by paracellin-1 muta­tions. While being of some efficacy to correct biochemical changes, treatment did not prevent, however, progression to chronic renal failure, which is a feature of this disease.

…Read the rest of this article

Treatment of primary hypercalciuria

Introduction

Idiopathic hypercalciuria is the most frequent metabolic abnor­mality since up to 40 to 60% of patients with nephrolithiasis are hypercalciuric. Fasting hypercalciuria, accompanies id­iopathic hypercalciuria in up to 50% of the patients. It is widely agreed that high calcium excretion may be causative for stone disease, because the higher calcium concentration, the higher the state of saturation with the calcium forming salts. However, a more general involvement of mineral metabolism, and in particular bone turnover, comes from the fact that virtu­ally all of these patients tend to develop a negative external balance of calcium, because renal loss overtakes net calcium absorption at the intestine. We care about you health 

The mechanisms of hypercalciuria are complex and not fully clarified as yet, and this issue is the object of another article in the Journal. Anyway, a better understanding of the pathogene­sis of hypercalciuria represents the basis of the different thera­peutic options so far pursued, which will be the object of the present review. These are listed in Table I. The points concern­ing the dependence of calcium excretion on dietary factors will be omitted, being treated elsewhere in this issue. …Read the rest of this article

Pleural effusions in the yellow nail syndrome are thought to be secondary to dysfunction of pleural lymphatics. Once present, they tend to persist and may recur rapidly after therapeutic thoracentesis, making this an impractical option in many symptomatic patients. Chemical pleurodesis using quinacrine (Atabrine) and tetracycline has been successful in two patients. Nine patients have been treated successfully with open pleural abrasion, pleurectomy or decortica­tion. Unfortunately, chemical pleurodesis causes pain and discomfort and has an appreciable failure rate, and open pleural abrasion and pleurectomy, while very effective, are major surgical procedures associated with a perioperative morbidity of up to 10 percent.

…Read the rest of this article

DISCUSSION

The data reported in this study do not support the notion of a strong relationship between hypoxemia per se and an objective measure of EDS in a group of patients with chronic daytime and nocturnal hypoxe­mia. Taken together, this group of patients with COPD did not reveal any evidence of subjective or objective EDS as assessed by a reliable physiologic measure of sleepiness. Furthermore, Guilleminault et al, in a recent study, also found no relationship between hypoxemia and mean sleep onset latencies with MSLT defined mild vs severe sleepiness in patients with OSAS.

…Read the rest of this article

Table 1 presents a comparison of the age, weight, and waking respiratory measures. Overall (n=14), there was no significant correlation between mean sleep onset latencies on the MSLT and waking Pa02 (- .13), PaC02 (.02), FEV, (.04), or mean spontaneous desaturation during sleep (.31). The mean sleep onset latencies were well within the published normal range as well as the normal range for our laboratory (unpub­lished data). Only two subjects exhibited a single sleep onset REM period.

…Read the rest of this article

Fourteen male patients with stable COPD were randomly se­lected from the Chest Medicine Clinic at the Veterans Administra­tion Medical Center in Oklahoma City. Patients were selected without regard to the presence or absence of daytime sleepiness. The mean age was 60 years (range, 48 to 72 years). Patients were selected with a waking Pa02 of less than 70 mm Hg and less than 50 percent predicted FEV,. All patients were in stable condition receiving optimal therapeutic measures with no evidence of acute pulmonary disease or respiratory failure. None of the patients was receiving sedatives or psychotropic drugs at the time of the study. Clinically, none of these patients had complaints of significant daytime sleepiness.

…Read the rest of this article

 Chronic Obstructive Pulmonary Disease

The common occurrence of excessive daytime sleepiness (EDS) in patients with obstructive sleep apnea remains perhaps the most enigmatic aspect of what has been called the obstructive sleep apnea syndrome (OSAS). Initial speculation related EDS to the most obvious cause, ie, sleep deprivation, since it had been noted that these patients have numerous arousals from sleep secondary to obstructive apneic events. In a subsequent study from our laboratory, it was found that patients with equivalent sleep disruption (matched on the basis of the number of upper airway obstructions per unit time) had markedly different subjective complaints of EDS. This study documented the fact that patients with complaints of EDS had a significantly greater degree of nocturnal oxyhemoglobin desaturation than those who were without subjective daytime sleepiness.

…Read the rest of this article