Multiple sclerosis prevalence among Sardinians: further evidence against the latitude gradient theory

A descriptive epidemiological survey was extended to the whole province of Sassari, northern Sardinia between latitudes 40 degrees 30' N and 41 degrees N. Results showed a crude total prevalence rate of 144.4 per 100000 on prevalence day (31 December 1997), and an onset-adjusted prevalence rate of 149.7 per 100000. The total average annual incidence rate was 4.9 per 100000 for the whole time interval studied (1968-1997), having increased from 2.0 in 1968-1972 to 6.8 in the last quinquennium considered. A substantial improvement in MS case ascertainment due to the introduction of new diagnostic procedures might account for such rates in Sardinia as well as in other Italian regions. However, when comparing our data with those obtained in the province of Ferrara, in the same time frames (1968-1997), a nine-fold versus a five-fold increase of MS prevalence was detected in Ferrara and Sassari, respectively. MS incidence temporal trend also notably increased in Sassari, but remained substantially stable in Ferrara. The progressive shortening of the time interval between clinical onset and diagnosis, and the proportion of benign-mild MS cases, were similar in both studies, thus suggesting a similar diagnostic accuracy. In our opinion, the repeatedly assessed increase of MS frequency in our province, at least partially does represent an actual rise of MS risk among Sardinians, thus disproving the latitude gradient-based theory (i.e. prevalence rates correlate with geographical latitudes) and supporting the hypothesis of a "Sardinian focus" of MS in a genetically susceptible population.

Multiple sclerosis epidemiology in Sardinia: evidence for a true increasing risk

OBJECTIVES

To update prevalence and incidence rates of MS among Sardinians.

MATERIALS AND METHODS

The present work is a "spider" kind of population based survey, conducted over the interval 1968-97, on patients with MS (Poser criteria) living in the province of Sassari, Northern Sardinia (454,904 population).

RESULTS

A crude total prevalence rate of 144.4 per 100,000, an onset-adjusted prevalence rate of 149.7 per 100,000 and an average annual incidence rate of 8.2 for the period 1993-7 were found.

CONCLUSION

Repeated epidemiological assessments of MS in Sardinia over decades have shown that the island is at high risk for MS. The present work highlights that MS incidence in Sardinia has been increasing over time. Although a substantial and widely spread improvement in MS case ascertainment can be postulated as the reason for such observations, a comparison between our data and those recently reported from a more industrialized province in Northern Italy seems to prove an at least partially real increase in MS risk among Sardinians and favours the hypothesis of a MS "Sardinian focus" as related to its latitude.

Maturation and translation mechanisms involved in the expression of a myb gene of rice

We have isolated two overlapping cDNAs coding for a MYB-related protein expressed in aerobic and anaerobic rice (Oryza sativa) roots and coleoptiles. Analysis of their sequences reveals some peculiar features, suggesting the presence of post-transcriptional regulation events: an upstream ORF, two unspliced introns and a putative leucine zipper in the ORF coded by the unspliced RNA. Transient expression in protoplasts indicates that the upstream ORF inhibits expression of a downstream coding sequence. Finally, we demonstrated that anoxia, in roots, increases the ratio between the spliced and the unspliced mRNA and affects the expression of other myb-related genes.

Effects of pyridostigmine, corticotropin-releasing hormone and growth hormone-releasing hormone on the pituitary-adrenal axis and on growth hormone secretion in dementia

Alterations of neuroendocrinological indices determined by the impaired regulating effects of cholinergic neurotransmission have been described in primary dementia. In this study we have evaluated the effects of acetylcholinesterase inhibition by pyridostigmine on growth hormone (GH), adrenocorticotropic hormone (ACTH) and cortisol secretion and on their responses to GH-releasing hormone (GHRH) and corticotropin-releasing hormone (CRH) in 7 patients with primary degenerative dementia and in 8 sex- and age-matched controls. Demented subjects showed higher cortisol basal levels and lower ACTH levels than controls. Pyridostigmine increased the GH response to GHRH in both groups, the effect being significantly enhanced in patients. An increase of ACTH and cortisol levels was found in both groups after pyridostigmine and CRH administration. Pyridostigmine pretreatment significantly increased the ACTH response to CRH in controls but not in patients. The obtained data may indicate that a muscarinic receptor upregulation and an impairment of somatostatinergic function are operative in the regulation of GH secretion in dementia. An underlying hyperactivity of the hypothalamic-pituitary-adrenal axis impairs the responses of ACTH and cortisol to CRH in this disorder.

A case of hyperglycemic hyperosmolar non-ketotic coma during anesthesia: a possible cause of failed re-awakening

The case of a non diabetic 6-year-old boy affected by Down's syndrome, who developed hyperosmolar hyperglycemic non-ketotic coma following the infusion of hypertonic dextrose solution during general anesthesia for a surgical procedure for cryptorchidism is reported. Following surgery, the patient remained deeply comatose and generalized seizures occurred. Hyperosmolarity due to hyperglycemia and acidosis were reduced by administration of insulin at low rate, hypotonic saline and sodium-bicarbonate solutions. The patient's clinical conditions promptly improved following normalization of blood glucose levels. An oral glucose tolerance test performed three months later was normal. The authors emphasize the potential risk of hyperosmolar hyperglycemic non-ketotic coma also in non diabetic patients treated with hypertonic dextrose solutions, during surgery events.