Letter

SIR-Comparison of the Biochemical and Hormonal Acute Effects of Calcium Salts Reginster et al. [1] recently compared the acute metabolic effects of oral administration of four calcium preparations: two of calcium gluconolactate and carbonate (Calcium Sandoz Forte effervescent tablets and Sandocal sachets), one of tricalcium phosphate (Ostram) and one of calcium citrate (Cacit). In that study, the calcium citrate group showed the greatest increase in serum calcium and inhibition of parathyroid hormone (PTH) secretion. The results were in accordance with previous reports emphasizing the good intestinal absorption of calcium citrate [2]. In a group of subjects similar to that studied by Reginster (10 young healthy adult males, 20-30 years old) we have compared the biochemical and hormonal acute effects of the oral intake of the same calcium citrate preparation (Cacit 1000; Procter & Gamble Pharmaceuticals France) with those of a preparation combining citrate and pidolate of calcium (Efical 1000 mg sachet; Laboratoires Millot-Solac, France) and those of a preparation containing pure calcium carbonate (Orocal 500 mg; Laboratoire Th6ramex, Monaco). The dose of administered elemental calcium (1 g) was the same as in Reginster's study. The subjects fasted for 12h overnight before and throughout the experiment. Blood was sampled at baseline and at 1, 2, 3 and 4h after the ingestion of calciurn, in order to measure total and ionized calcium, phosphate and intact PTH (1-84). Urine was collecting during a 2-h interval before, and 4 h after, oral calcium loading to measure calcium, phosphate and creatinine. These three calcium preparations induced a significant increase in both total and ionized serum calcium, with a maximum 2-3 h after oral calcium loading. The maximum increase in total serum calcium was significantly higher after ingestion of either calcium citrate (+ 8.5%), or calcium citrate and pidolate (+8.2%), than after administration of calcium carbonate (+5.56%) (p <0.05). The increase in serum ionized calcium l h after ingestion of either calcium citrate (+5.3%) or calcium citrate and pidolate (+5.7%) was significantly higher than after ingestion of calcium carbonate (+3.0%) (p <0.05 andp <0.01, respectively). Two and three hours after oral ingestion, calcium citrate and pidolate induced an increase in serum ionized calcium which was significantly higher (9.84% and 9.53%, respectively) than calcium carbonate (6.53% and 6.36%, respectively) (av <0.01 in each case). Calcium urinary excretion reached its maximum between 2 h and 4 h, and was significantly higher with either calcium citrate or calcium citrate and pidolate than with calcium carbonate (p <0.05 in each case). All three salts induced a highly statistically significant fall in serum PTH(1-84) between l h and 4h (p <0.001). The serum PTH (1-84) concentrations were lowest at 2 h and increased thereafter. At all time points the concentrations of serum PTH(1-84) were significantly lower after administration of either calcium citrate or calcium citrate plus pidolate than after administration of calcium carbonate (from p <0.05 to p <0.001). The decrease in serum PTH(1-84) when expressed as a percentage of baseline value was not significantly different between the two preparations of calcium citrate, which inhibited PTH(1-84) secretion more efficiently than calcium carbonate (fromp <0.05 top <0.001) (Table 1). Our results are in good agreement with those obtained by Reginster et al. [1] with the same calcium citrate salt Cacit (maximal PTH inhibition -59.6% v 65.8%), demonstrating the striking efficacy of citrate salts in inhibiting PTH secretion. The results of these two studies could be used to give an idea of the relative digestive absorption of six commercially available calcium salts.


RE: TESTICULAR HISTOPATHOLOGICAL DIAGNOSIS AS A PREDICTIVE FACTOR FOR RETRIEVING SPERMATOZOA FOR ICSI IN NON-OBSTRUCTIVE AZOOSPERMIC PATIENTS
GLINA S, SOARES JB, ANTUNES JR N, GALUPPO AG, PAZ LB, WONCHOCKIER R Int Braz J Urol. 2005; 31: 338-341 Dear Editor, ICSI has allowed some couples to have genetic offspring using a small number of spermatozoa from the testes.It seems that these patients have small foci of spermatogenesis in the testes even though remaining azoospermic.It is possible that they present a minimum quantitative threshold of spermatogenesis which must be exceeded for any spermatozoa to reach the ejaculate, estimated to be 4 to 6 mature spermatids per tubule (1).Conventional teaching has been that men with azoospermia and serum follicle-stimulating hormone concentrations more than 2 to 3 times normal have severe testicular failure not amenable by any conventional therapy.However, Kim et al. demonstrated that, 30% of those men who were previously advised against testicular biopsy if atrophy was present, were potentially able to initiate a pregnancy in the era of testicular sperm extraction with advanced micromanipulation techniques (2).
We have read with great interest the recent article by Glina et al. showing that the percentage of patients with positive sperm retrieval according to histological testicular pattern was 50% in patients with hypospermatogenesis, 33% in patients with maturation arrest, and 40% in patients with Sertoli cell only syndrome.Even though differences in sperm retrieval compared to other series (80% for hypospermatogenesis, 50% for maturation arrest and 20% for Sertoli cell only syndrome) have been brought to our attention, an important message was delivered by their article.The pregnancy rate was only 3/16 procedures, (18.75%) in patients with non-obstructive azoospermia.This does not differ from a previous study that showed a pregnancy rate of 22% in patients with non-obstructive azoospermia (3).
Non-obstructive azoospermic patients may be suffering from a genetic defect or a genetically determined barrier to reproduction.Therefore, it is not surprising that, despite succeeding in extracting live spermatozoa in non-obstructive cases of azoospermia, the pregnancy rates are significantly lower when compared to those with obstructive azoospermia (4).
Y-chromosome microdeletion screening is recommended in cases of severe spermatogenetic impairment by numerous societies (Société Française de Génétique Humaine, European Society of Human Reproduction and Embryology, European Association of Urology and American Urological Association).Investigators identified different chromosomal regions containing independent loci related to male gametogenesis and azoospermia (azoospermia factors, or AZFs).More specifically, at least 3 non-overlapping regions of Yq (called AZFa, AZFb, and AZFc) have been firmly related to male infertility, which may be related with the possibility of sperm retrieval for assisted reproductive techniques.Consequently, molecular diagnosis of Y-chromosome microdeletions is now available and routinely indicated in subfertile patients with low sperm concentrations (< 5 X 10 6 /mL).As many cases of male infertility are likely to be of a genetic origin, the potential risk of transmitting infertility to future generations is of great concern.In fact, any patient with secretory azoospermia should undergo a Karyotype and Y chromosome microdeletion search.Therefore, the authors should state the reason for not asking for Y microdeletion evaluation.

REPLY BY AUTHORS
We fully agree with Dr. Pasqualotto that any man with severe oligospermia or non-obstructive azoospermia that would be submitted to ICSI should undergo a complete genetic screening.This includes kariotype and Y chromosome microdelection search and this is part of our routine work-up.However, we did not report that in our paper because the objective was to learn, in our experience, the role of previous histological testicular pattern as a prognosis for sperm retrieval in non-obstructive azoospermic men.