Life-threatening complications of streptococcal sepsis: a PICU contemporary series.

BACKGROUND: Life-threatening streptococcal sepsis nowadays represents an uncommon event in previously healthy infants and children. Critically ill patients suffering from severe streptococcal sepsis complications may present with pre-antibiotic era clinical pictures and require a timely clinical approach to achieve restitutio ad integrum. RESULTS: We report a series of four patient groups affected by an uncommon life-threatening streptococcal sepsis, each of them exhibiting some distinct features. Streptococcus Agalactiae sepsis was associated with cerebral thrombotic/ischaemic lesions, whereas severe cardiogenic shock was prominent in the Streptococcus Viridans group; Streptococcus Faecalis and ß-hemolytic group A Streptococcus patients mostly reported lung complications. CONCLUSIONS: Previous antibiotic treatments should not delay aggressive treatment in the intensive care setting. Early diagnostic suspicion, as well as appropriate and aggressive treatment provided within an intensive care setting are crucial for the clinical outcome.

Ketamine effects on local cerebral blood flow and metabolism in the rat.

The effects of an anesthetic dose (100 mg/kg) of ketamine, a phencyclidine derivative, on local rates of cerebral glucose utilization (LCGU) and CBF (LCBF) have been investigated by the quantitative [14C]2-deoxy-glucose and [14C]iodoantipyrine techniques in the unparalyzed, spontaneously breathing rat. In ketamine-injected animals, LCGU was significantly increased in some limbic structures and decreased in inferior colliculus, vestibular, and cerebellar nuclei. The degree and spatial distribution of drug-induced changes was similar for local blood flow rates, LCBF being increased in limbic regions and decreased in the inferior colliculus. Although Paco2 values were higher in anesthetized animals, the pattern of LCBF/LCGU ratios was not significantly affected by ketamine in the 36 brain regions examined in this study. So, at least in the rat and at the anesthetic level studied here, a net vasodilatory in vivo effect was not observed. These results support the hypothesis that CBF changes induced by the drug in animals and man are primarily related to the metabolic effects exerted by ketamine on cerebral structures.

Correlation between amount of retinal afferents to the pretectal nucleus of the optic tract and dorsal terminal accessory optic nucleus and performance of horizontal optokinetic reflex in rat.

Intraocular kainic acid injection in Long-Evans rats induces loss of retinal afferents to subcortical visual centers as assessed by the axoplasmic transport of [14C]valine. The optical terminal fields of the pretectal nucleus of the optic tract (NOT), superior colliculus and accessory optic system (AOS) nuclei appear particularly affected. Since NOT and the AOS dorsal terminal nucleus (DTN) represent the first relay station of the visuomotor pathway mediating horizontal optokinetic nystagmus (HOKR), we have studied the characteristics of HOKR after various degrees of retinal deafferentation of these nuclei induced by intraocular KA injection. Taking advantage of the arrangement of the primary optic projections to NOT-DTN, that in rats are almost entirely crossed, in each animal, monocular HOKR induced by stimulation of the injected eye was compared to monocular HOKR elicited by stimulation of the intact, ipsilateral eye. Following NOT-DTN optic denervation, HOKR gain always worsened, and in a way, that the greater the deficits of retinal afferents, the greater the HOKR inability to compensate for visual motion. Furthermore, for any given retinal denervation the higher the stimulus velocity, the greater the HOKR deficit. While the correlation between HOKR gain and the amount of retinal afferents to NOT-DTN would seem to indicate a functional homogeneity of the retinal ganglion cells sending axons to these nuclei, the finding that the extent of HOKR impairment also varied with velocity might not support the above view.

Vertical and horizontal visual whole-field motion differently affect the metabolic activity of the rat medial terminal nucleus.

The metabolic activity of the medial terminal nucleus (MTN) of the Accessory Optic System was studied by means of the [14C]2-deoxyglucose (2-DG) method in Long-Evans rats exposed to moving and stationary visual stimuli. In particular we explored the rate of local cerebral glucose utilization (LCGU) and the spatial distribution of 2-DG uptake within MTN related to visual stimuli capable of triggering optokinetic nystagmus. It was found that increases in MTN metabolism accompanied the retinal slip signals evoked by whole-field visual patterns moving in the vertical as well as in the horizontal direction. At the same level of luminous flux neither the same but stationary pattern, nor constant, diffuse illumination were able to elicit comparable changes in MTN metabolic rates. The effects of vertical and horizontal motions differed, however, from each other. In binocular testing LCGU rates resulted significantly higher after vertically moving patterns and upon the same stimulus condition the spatial distribution of 2-DG matched very closely the spatial distribution of the retinal afferents and the cellular density within MTN, in sharp contrast with the diffuse spreading out of the label across the nucleus following horizontal motion. In monocular testings only the vertically moving patterns were able to increase LCGU rates significantly and then in contralateral MTN alone. However, comparison between the levels of glucose consumption measured in binocular and in monocular vision also showed the involvement of the uncrossed retinal path in relaying the retinal slip signals to MTN. No difference in LCGU and in spatial distribution of the label were finally observed in relation to the upward or to the downward direction of the moving pattern.

Tonic pain time-dependently affects beta-endorphin-like immunoreactivity in the ventral periaqueductal gray matter of the rat brain.

beta-Endorphin-like immunoreactivity (B-EP-LI) levels have been investigated in the ventral periaqueductal gray matter (vPAG) of rats killed 30, 60 or 120 min after the subcutaneous injection of dilute formalin (0.08 ml, 5%) in one fore- or hindpaw, or comparable handling. B-EP-LI was estimated by radioimmunoassay, using an anti-camel B-EP serum directed against the C-terminal portion of B-EP molecule. In both fore- and hindlimb groups vPAG B-EP-LI values were significantly increased 60 and 120 min after the injection relative to controls. Values from animals killed 120 min after formalin injection were higher than the ones at 30 and 60 min, forelimb effects being quantitatively more pronounced. The increase in B-EP-LI appeared distributed along the whole rostrocaudal extent of the region.

Intraocular injection of APB decreases the metabolic response of the rat superior colliculus.

The functional activity of the superior colliculus (SC) following flash stimulation was examined by means of 2-deoxyglucose (2DG) method in monocularly enucleated Long-Evans rats intraocularly injected with a solution of 2-amino-4-phosphonobutyric acid (APB), able to silence the ON retinal activity. After APB injection SC layers recipient of retinal axons suffered a sustained 2DG decrease as compared to controls. Moreover, whereas glucose utilization in normal rat SC appears unevenly distributed and closely related to retinal axon density, by contrast, APB-treated rats showed a rather uniform metabolic activity throughout the SC surface. Furthermore, we calculated the 2DG uptake percentage reduction in 12 SC loci of APB rats in respect to homologous loci of controls: glucose utilization decreases at the loci largely differ from each other, showing that retinal axons carrying ON activity are dispersed over the SC in a mosaic pattern. Thus, the SC metabolic map should be representative of its retinotopic organization which, in turn, depends on the asymmetric distribution in the rat's retina of W-like as well as of other ganglion cell types.

Kainic acid differently affects retinal projections to different pretectal nuclei.

Kainic acid (KA) damages retinal cells, thus impairing axonal anterograde transport of labeled aminoacids when injected intravitreally. In this study, Long-Evans rats were injected with KA into one eye, and seven days later were binocularly injected with 14C-valine. The extent of residual retinal afferents to two pretectal nuclei was calculated as the percentage of the contralateral, intact side. Projections to the nucleus of the optic tract (first relay station of the optokinetic pathway) appear significantly more affected than those to the olivary pretectal nucleus (involved in the pupillary light response). These results suggest a correlation between the functional properties of retinal ganglion cells and distinctive biochemical characteristics, such as their susceptibility to KA.

Pineal involvement in the alimentary behavior and taste preferences in the rat.

The purpose of this experiment was to explore the effects of pinealectomy or sham pinealectomy on circadian rhythms of taste preferences, food and fluid intake and body weight gain in rats. We compared the body weight gain, the amounts of food eaten and that of deionized water, total fluid, salt, sour, sweet and bitter near-threshold solutions consumed by rats before all surgical manipulations and after pinealectomy or sham pinealectomy. The results showed that the pineal gland does not exert a major influence on circadian organization of taste preferences, drinking, feeding and body weight modifications in the rat. The failure of pinealectomy to modify light/dark rhythms of taste preferences and other related alimentary behaviors may be explained by the fact that pinealectomy does not completely eliminate circulating melatonin.

A rapid HPLC technique for determining levels of histamine in tears from normal and inflamed human eyes.

Because of the important role of histamine in the inflammatory process, the measurement of histamine levels in tears has been considered as a possible index of eye irritancy. Histamine levels have been measured using an HPLC procedure involving fluorimetric detection after fluorescamine derivatization. Analyses, at picomole levels, were carried out in less than 5 minutes using 10 microliter of tear samples collected from either normal or inflamed human eyes.

Surface modification of proteins. Activation of monomethoxy-polyethylene glycols by phenylchloroformates and modification of ribonuclease and superoxide dismutase.

A single-step method of activation of monomethoxypolyethylene glycols suitable for its binding to polypeptides and proteins is proposed. Based on the reaction with 2,4,5-trichlorophenylchloroformate or p-nitrophenylchloroformate, it gives reactive PEG-phenylcarbonate derivatives. The PEG intermediate is stable on storage, the activating group is easily quantified,and the reaction with amino acid and proteins proceeds rapidly at pH near neutrality. The PEG derivatization of enzymes with this procedure is less inactivating than those previously reported. Ribonuclease and superoxide dismutase were modified and the effect of (a) bound polymer on clearance time in rats, (b) antibody recognition, and (c) on the enzymatic activity toward low and high molecular weight substrates were studied.

Daytime melatonin treatment influences food carrying (hoarding) behavior in rats.

OBJECTIVE: Three experiments were performed to verify whether melatonin (MEL) may influence hoarding behavior in rats. This hypothesis was supported by the consideration that leptin treatment decreases food hoarding in hamsters and that an inverse relation exists between plasma leptin concentration and MEL treatment. METHODS: Male Sprague-Dawley rats housed individually and kept on 12h:12h light-dark cycle were used. First experiment was performed to check whether a bimodal distribution of food hoarding scores exists in rats, and to select two groups of high (HH-rats) or low (LH-rats) hoarding. Second experiment was designed to verify whether MEL treatment modifies food-hoarding, while the third one was performed to investigate whether MEL treatment was able to modify the reciprocal relation between leptin and MEL plasma concentration. RESULTS: In rats the hoarding tendency fell into a bimodal distribution and the plasma leptin concentration was significantly higher in HH-rats than LH-rats. When MEL was injected, circulating concentration of leptin was decreased in both HH-rats and LH-rats and such MEL treatment significantly increased the number of pellets hoarded by LH-rats but not that hoarded by HH-rats. CONCLUSIONS: MEL influences the food-hoarding in rats either directly, or indirectly by the MEL and leptin reciprocal interaction. Our results support the hypothesis that the endocrine system either directly, by the action of one or more combined hormones (MEL, leptin), or indirectly via its actions on neural substrates determines, at least in part, food-hoarding of rats.

Rapid eye movements in the kitten.

The horizontal and vertical components of the rapid eye movements (REMs) of paradoxical sleep have been analysed in kittens of a few weeks of age and in adult cats. The following differences between young and adult animals have been found: (a) in kittens the horizontal and vertical components of the REMs are of saccadic type; in adult cats only the vertical components are saccades; (b) the peak velocity and the rate of velocity increase are surprisingly greater in kittens than in adult cats. These data might indicate that REM sleep plays a role in the maturation of neuronal organization of eye movements.

Olivofloccular circuit in oculomotor control: binocular optokinetic stimulation.

The metabolic activation of the olivocerebellar pathway during binocular optokinetic stimulation was studied in the guinea pig, by means of the semiquantitative 14C-2-deoxyglucose (2DG) technique. The experimental group underwent binocular horizontal stimulation, whereas the control animals were either kept in the dark or allowed to view a stationary pattern. The local metabolic activity index in the dorsal cap of the inferior olive was higher on the side contralateral to the eye that had been stimulated in the temporonasal (T-N) direction in the horizontal group; in contrast, the floccular region showed higher activity on the side ipsilateral to the T-N-stimulated eye. These findings support the involvement of the olivocerebellar pathway in the horizontal optokinetic response. A phylogenetic hypothesis is suggested to explain inconsistent results found in the literature.

[Esters and amides of salicyloylamino acids]. / Esteri ed ammidi di saliciloilamminoacidi

N-Salicyloylamino acids, esters and amides have been prepared by the usual condensation methods and also by methods which may demonstrate 2-(o-hydroxyphenyl)oxazoline-5-ones as possible reaction intermediates. Some derivatives display pharmacological activities.