No abstract

To determine the impact of a trace element and vitamin supplementation on infectious morbidity, a double-blind controlled trial was performed on 81 elderly subjects in a geriatric center during a 2-year period. Subjects were randomly assigned to one of four treatment groups, and received daily: placebo; trace elements /zinc 20 mg; selenium 100 µg); vitamins (vitamin C 120 mg; β-carotene 6 mg; α-tocopherol 15 mg); or a combination of trace elements and vitamins at equal doses. (1) Before supplementation, low serum values in vitamin C, folate, zinc and selenium were observed in more than two thirds of the patients. (2) After 6 months of supplementation, a significant increase in vitamin and trace element serum levels was obtained in the corresponding treatment groups: a plateau was then observed for the whole study. (3) Subjects who received trace elements (zinc and selenium) alone or associated with vitamins had significantly less infectious events during the 2 years of supplementation. These results indicate that supplementation with low doses of vitamins and trace elements is able to rapidly correct corresponding deficiencies in the institutionalized elderly. Moreover, zinc and selenium reduced infectious events.

No abstract

Unilateral dorsal rhizotomies were done at the cervicothoracic and lumbosacral spinal cord levels in rats. In preliminary experiments dermatome maps were determined for the roots to be sectioned. The behavior of 37 rats was observed for many months after the rhizotomies. The rats with the dorsal roots sectioned in the cervicothoracic spinal cord exhibited the following behavior: at the border of the skin adjacent to the zone of deafferentation, the rat scratched vigorously and progressively denuded the skin; self-mutilation of varying degrees occurred in the deafferented limb. In some animals scratching occurred in the contralateral skin dermatome opposite to the partially deafferented zone. The rats with the dorsal roots sectioned at the lumbosacral level exhibited hypersensitivity to cutaneous stimulation but there was no scratching or self-mutilation. These results are discussed in the light of previous similar research.

Biochemical mapping of five different peptide-like materials--calcitonin gene-related peptide (CGRP), substance P (SP), Met5-enkephalin (ME), cholecystokinin (CCK), and dynorphin A (1-8) (DYN)--was conducted in the dorsal and ventral zones of the spinal cord at the cervical, thoracic, and lumbar levels in 3-month-old rats 10 days after unilateral dorsal rhizotomy at the cervical level (C4-T2) or after neonatal administration of capsaicin (50 mg/kg s.c.). In control rats, all peptide-like materials were more abundant in the dorsal than in the ventral zone all along the spinal cord. However, in both zones, absolute concentrations of CGRP, SP, ME, and CCK were significantly higher at the lumbar than at the cervical level. Rhizotomy-induced CGRP depletion (-85%) within the ipsilateral dorsal zone of the cervical cord was more pronounced than that due to neonatal capsaicin (-60%), a finding suggesting that this peptide is contained in both capsaicin-sensitive (mostly unmyelinated) and -insensitive (myelinated) primary afferent fibers. In contrast, similar depletions of SP (-50%) were observed after dorsal rhizotomy and neonatal capsaicin treatment, as expected from the presence of SP only in the capsaicin-sensitive small-diameter primary afferent fibers. Although the other three peptides remained unaffected all along the cord by either intervention, evidence for the existence of capsaicin-insensitive CCKergic primary afferent fibers could be inferred from the increased accumulation of CCK (together with SP and CGRP) in dorsal root ganglia ipsilateral to dorsal root sections.

Autoradiographic studies were performed in combination with dorsal rhizotomy or selective lesion of descending serotonergic or noradrenergic systems in an attempt to identify the neuronal cell types endowed with the serotonin 5-HT1A, 5-HT1B and 5-HT3 receptors in the rat spinal cord. Unilateral sectioning of seven dorsal roots (C4-T2) at the cervical level produced a marked decrease (approximately-75%, 10 days after the surgery) in the binding of [125I]iodozacopride to 5-HT3 receptors in the superficial layers of the ipsilateral dorsal horn, further confirming the preferential location of these receptors on primary afferent fibres. In addition, a significant decrease (approximately 20%) in the binding of [3H]8-OH-DPAT to 5-HT1A receptors and of [125I]GTI to 5-HT1B receptors was also observed in the same spinal area in rhizotomized rats, suggesting that a small proportion of these receptors are also located on primary afferent fibres. The labelling of 5-HT1B receptors was significantly decreased (-12%) in the dorsal horn at the cervical (but not the lumbar) level, and that of 5-HT3 receptors was unchanged in the whole spinal cord in rats whose descending serotonergic projections had been destroyed by 5,7-dihydroxytryptamine. Conversely, the labelling of 5-HT1A receptors was significantly increased in the cervical (+13%) and lumbar (+42%) dorsal horn in 5,7-dihydroxytryptamine-lesioned rats. Similarly, [3H]8-OH-DPAT binding to 5-HT1A receptors significantly increased (+26%) in the lumbar (but not the cervical) dorsal horn in rats whose noradrenergic systems had been lesioned by DSP-4. The labelling of 5-HT1B receptors was also increased (+31% at the cervical level; +17% at the lumbar level), whereas that of 5-HT3 receptors remained unchanged in these animals. These data indicate that complex adaptive changes in the expression of 5-HT1A and 5-HT1B receptors occurred in the rat spinal cord following the lesion of descending monoaminergic systems.

No abstract

No abstract