Adult-type hypolactasia genotyping in Northern Italy: prevalence of C/T-13910 polymorphism and questions after comparison with existing data

A genotyping assay was setup to assess the prevalence, in the population of a Northern Italian city, of the C/T-13910 single nucleotide polymorphism, closely associated to lactose malabsorption in many world areas including Sardinia. The results were compared to published Italian data, in order to evaluate the worth of a future validation of the assay for use in routine practice. DNA was extracted from blood samples of 123 randomly chosen healthy blood donors coming from the same city area, and was analyzed by a real-time polymerase chain reaction (PCR) genotyping assay; the frequency of the hypolactasia-associated CC-genotype was compared to the weighted average of results extracted from studies reporting the frequency of hypolactasic phenotype or genotype in nearby or distant Italian regions. Sixty-five percent of donors carried the CC-genotype, a percentage similar to other northern Italian cities, but significantly higher than what previously determined in surrounding Italian regions at the phenotype level, i.e. by breath test. This discrepancy parallels recent reports of non concordance between results of genotyping and hypolactasic phenotype in some world areas, including a neighbouring Northern Italian city. A north-south gradient of CC-prevalence was also observed. These results reinforce the notion of wide inter-regional variations in the frequency of C/T-13910 polymorphism and of incostant concordance with hypolactasic phenotype, even in subjects from the same country. Given the unsatisfactory results recently obtained from validation of a related assay in a neighbouring city, the authors decided not to proceed further and keep the assay only as a diagnostic aid in special situations.

Renewal of the T-cell compartment in multiple sclerosis patients treated with glatiramer acetate

The immunomodulating activity of glatiramer acetate on T-cells of multiple sclerosis patients has only been partially clarified. The objective of this work was to investigate whether glatiramer acetate modifies thymic release of newly produced T-cells and the peripheral composition of the T-cell repertoire. T-cell receptor excision circles, (thymic) naive (CD4(+)CD45RA(+)CCR7(+)CD31(+)) T helper cells, and central (CD4(+)CD45RA(-)CCR7(+)) and effector (CD4(+)CD45RA(-)CCR7(-)) memory T-cells were evaluated in 89 untreated patients, 84 patients treated for at least 1 year, and 31 patients beginning treatment at the time of inclusion in the study and then followed-up for 12 months; controls were 81 healthy donors. The T-cell repertoire was analysed in selected samples. The percentage of (thymic)naive T helper cells was diminished in untreated patients, but rose to control values in treated subjects; a decrease in central memory T-cells was also observed in treated patients. Follow-up patients could be divided into two subgroups, one showing unmodified (thymic)naive T helper cells and T-cell diversity, the other in which the increased release of new T-cells was accompanied by modifications of the T-cell repertoire. Glatiramer acetate modifies the peripheral T-cell pool by activating a thymopoietic pathway of T-cell release that leads to a different setting of T-cell diversity and, likely, to a dilution of autoreactive T-cells.

In vitro and in vivo evaluation of an oscillometric device for monitoring blood pressure in dialysis patients

BACKGROUND

Nowadays, an increasing number of dialysis machines lodge a blood pressure (BP) measuring device, whose accuracy has a clear implication for the patients' clinical management.

METHODS

An automated oscillometric sphygmomanometer (HD-BPM by Gambro Dasco) used during haemodialysis was submitted to both in vitro and in vivo tests, in order to evaluate some modifications aimed at improving measurement accuracy and consistency. The results were compared with those obtained by another oscillometric monitor (BX-100 by Colin). Three steps of evaluation were followed. First, the maintenance of the overall accuracy requirements prescribed by ANSI/AAMI SP-10 standard was verified. Then, an in vitro validation was carried out by using a test simulator. Finally, during a multi-centre field trial, 392 BP measurement sessions on 53 dialysis patients were collected. Every session consisted of two consecutive intra-dialysis measurements by the oscillometric monitors, each one performed simultaneously to an auscultatory measurement. A comparison with the intra-arterial method was performed as well.

RESULTS

When compared with an in vivo data set previously collected, the HD-BPM accuracy complied with required limits. Second, the internal repeatability with respect to the simulator was satisfactory (SD of the differences between device and simulator readings: HD-BPM: systolic = 5.7, diastolic = 4.2; BX-100: systolic = 4.2, diastolic = 5.5 mmHg). Moreover, the comparison between oscillometric and auscultatory methods during in vivo trial gave similar results for the two monitors, even if systolic pressure SD exceeds the limit recommended by ANSI/AAMI SP-10 (mean value of the differences +/- SD: HD-BPM: systolic = 0.5 +/- 9.0, diastolic = 1.5 +/- 6.9; BX-100: systolic = 3.1 +/- 8.2, diastolic = -2.0 +/- 7.6 mmHg).

CONCLUSIONS

These data underline the importance of performing accuracy evaluations for BP monitors in the conditions where they normally work, by using well-accepted protocols.

Validation of automated oscillometric sphygmomanometer (HDBPM) for arterial pressure measurement during haemodialysis

An HDBPM oscillometric sphygmomanometer used for the automatic measurement of arterial blood pressure is evaluated according to the ANSI/AAMI SP10-1992 standard. The accuracy of the HDBPM is ascertained by comparing it against the standard Riva-Rocci ascultatory method. Following the ascultatory method, two independent observers use the HDBPM devise to simultaneously measure the arterial blood pressure in 92 subjects of varying ages and having different blood pressures and arm sizes. High agreement is found when comparing the observers' pressure determinations (within 10 mmHg for 100% of observations). Correlation between the average of two ascultatory determinations and the HDBPM is high both for the systolic (r = 0.98) and diastolic (r = 0.94) pressures. The mean of the differences between the pressures measured by the observers and the HDBPM device are 0.2 mmHg (systolic) and -0.4 mmHg (diastolic). The percentages of readings within 10 mmHg between those taken by the observers and those taken by the HDBPM are 88% (systolic) and 97% (diastolic). These results largely satisfy current requirements.

Fasting and postprandial gastrointestinal motility in ulcer and non-ulcer dyspepsia

This study aimed to compare fasting and postprandial gastrointestinal motor patterns in patients with ulcer and non-ulcer dyspepsia. Forty five subjects were studied: 10 with uncomplicated gastric ulcer, eight with uncomplicated duodenal ulcer, 18 with chronic idiopathic dyspepsia, and nine healthy asymptomatic controls. Gastrointestinal fasting and postprandial motor patterns were recorded using a low compliance perfusion technique. The interdigestive antral cumulative motility index, computed for 30 minutes before the appearance of duodenal activity fronts, and the number of activity fronts with an antral component were significantly less in patients with ulcers and those with non-ulcer dyspepsia compared with asymptomatic controls. The patient groups also had a reduced antral motor response to a solid-liquid test meal compared with healthy controls. Intestinal motor abnormalities (bursts of non-propagated phasic pressure activity and discrete clustered contractions) were recorded in a minority of patients, all with associated irritable bowel symptoms. In conclusion, antral hypomotility is a frequent but nonspecific motor abnormality in dyspepsia; abnormal motor patterns of the small bowel are less frequent and seem to be confined to patients with concomitant irritable bowel syndrome.

Reversibility of gastrointestinal motor abnormalities in chronic intestinal pseudo-obstruction

A 43-year-old man with chronic intestinal pseudo-obstruction is presented. He had undergone two laparotomies in an attempt to eliminate the cause of repeated episodes suggestive of obstruction. Gastrointestinal manometry showed severe abnormalities compatible with the diagnosis of chronic intestinal pseudo-obstruction. Laboratory tests indicated the presence of intestinal malabsorption and villous atrophy. A gluten-free diet accompanied by 10 days of treatment with tetracycline and 2 short periods of treatment with cisapride led to gradual, but apparently complete, resolution of the pseudo-obstructive syndrome. Repeated manometric studies showed progressive normalization of both the fasting and postprandial upper gastrointestinal motor pattern.

[Comparison of methods: gastro-duodenal manometry and study of gastric emptying]

Traditionally, the stomach is regarded as two functional unit regions: 1) a proximal portion mainly involved in receptive relaxation and emptying of liquids; and 2) a distal portion that grinds, mixes and empties solids. Manometric and radioisotopic studies have been employed to construct such a physiological model. More recently, ad hoc designed studies have led to the identification of other factors that contribute to the regulation of gastric emptying. Antral, intestinal and pyloric motility, fundic tone and antropyloroduodenal coordination appear to be all involved in the regulation of gastric emptying. Nowadays, no single technique can simultaneously measure those parameters. Gastroduodenal manometry can be regarded as the most advanced technique, in studying gastrointestinal motility. Nevertheless, fundic tone, which is an important determinant of gastric emptying, cannot be concurrently recorded.