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Biomedical subjects

L Tamayo

Publications and source records attributed to L Tamayo.

At least 37 records · Page 2Linked to original sources
PubMed1987

Phacomatosis pigmentovascularis: a new syndrome? Report of four cases.

We examined four patients who had a combination of extensive nevus flammeus, significant oculocutaneous pigmentation, and severe neurologic alterations. All cases were sporadic. The vascular and neurologic alterations were clinically similar to those observed in the Sturge-Weber syndrome. The capillary vessels are ultrastructurally different in phacomatosis pigmentovascularis from those of a nevus flammeus in the Sturge-Weber syndrome; however, melanocytes of normal aspect were present in the middle and deep dermis. The characteristic oculocutaneous pigmentation probably represented a noncoincidental association. The term phacomatosis pigmentovascularis seems appropriate for this apparently new neurocutaneous syndrome.

Brain Diseases↗
PubMed1987

Retinoids in disorders of keratinization: their use in children.

During the last 10 years we treated 39 children with severe keratinization disorders with the aromatic retinoid etretinate. Six of these children were followed-up for 8-9 years. Mucocutaneous serum enzymatic and lipid side effects of etretinate were mild, transient and well tolerated. Osseous side effects were present after 4-6 years in all our 6 patients on prolonged retinoid therapy. Asymptomatic osseous neoformation and osseous reabsorption in the absence of calcium, phosphate, and alkaline phosphatase serum alterations have been observed. The growth and development curves and the sexual development of our patients (with exception of a patient with Rud's syndrome) have been normal. Osteoporosis and slender diaphysis were often present at initiation of therapy. On the basis of our findings and recent reports of the literature we suggest restricting retinoid therapy of keratinizing disorders in children to conditions severe enough to be physically, psychologically or socially incapacitating. In an attempt to reduce the risk of chronic toxicity and possibly to allow regression of initial bone alterations, intermittent therapy and combination therapy are recommended.

Adolescent↗
PubMed1986

Effects of morphine in the isolated mouse urinary bladder.

Acute morphine increased the responses to acetylcholine of the isolated mouse urinary bladder. A chronic morphine treatment did not change the responses of the urinary bladder to acetylcholine or ATP. The acute administration of morphine did not modify the contractile response to ATP in the urinary bladders from untreated or chronically morphine treated mice. Methadone and ketocyclazocine decreased the responses to the electrical stimulation of the urinary bladder. These depressant effects were not modified by naloxone. The results suggest the nonexistence of opiate receptors in the mouse urinary bladder and the lack of direct effects of morphine on the neuroeffector junction.

Acetylcholine↗
PubMed1985

Effects of ethylenediamine on morphine analgesia and tolerance-dependence in mice.

Ethylenediamine, a GABA receptor agonist induced a small hyperalgesic state in mice, but increased morphine analgesia. The interaction with this morphine effect was not dose-dependent. Ethylenediamine significantly antagonized tolerance development at relatively low doses (5-10 mg/kg). The GABA mimetic agent increased the frequency of abstinence signs in the naloxone-precipitated morphine withdrawal in mice. The effect of ethylenediamine on morphine withdrawal was suppressed by the irreversible GABA transaminase inhibitor, gamma-vinyl GABA.

Analgesia↗
PubMed1984

Effects of taurine on tolerance to and dependence on morphine in mice.

The effects of taurine on the analgesic response to morphine, on the intensity of tolerance and on physical dependence were examined. Taurine induced a hyperalgesic state and attenuated morphine analgesia in mice. The hyperalgesia was maximal at a dose level of 1.5 mg/kg i.p., while the effects of higher doses (6.0 and 10.0 mg/kg) were masked by a depression of the animals' gross behavior. Taurine induced a dose related antagonism of morphine tolerance. The amino acid administered 30 min before naloxone, produced a partial reduction in the abstinence signs in the chronically treated mice. Taurine also attenuated the abstinence behavior when administered during the course of dependence. The results are consistent with taurine antagonism to the known effects of morphine on intracellular calcium disposition in nervous tissue.

Analgesia↗
PubMed1983

Progressive cardiomyopathic lentiginosis: report of six cases and one autopsy.

Progressive cardiomyopathic lentiginosis (PCL) is a syndrome with progressive multisystem abnormalities. Lentigines, the cutaneous hallmark, are usually present from early age and are of utmost diagnostic value. Six children with PCL are reported. The most constant diagnostic features in this age group were multiple cutaneous lentigines, structural cardiac anomalies, and electrocardiographic alterations. Less constant findings were neurosensory deafness, short stature, and osseous, ocular, and genitourinary abnormalities.

Arrhythmias, Cardiac↗
PubMed1983

A dual action of valproic acid upon morphine analgesia and morphine withdrawal.

Effects of valproic acid administration on morphine analgesia and on morphine tolerance and dependence were investigated in mice. Valproate increased the reaction time to thermal stimulation in naive animals. This effect was additive with morphine when valproate was administered shortly before the analgesic. However, an antagonism was observed if a 4-hour period elapsed between valproate and morphine administration. When administered to mice receiving a sustained release preparation of morphine, valproate antagonized the development of tolerance to morphine. Valproate elicited a dual action on the abstinence signs observed after naloxone administration in morphine-treated mice. The effect consisted in a reduction of abstinence behavior if the anticonvulsant was administered a few minutes before naloxone; the same treatment increased the severity of the abstinence behavior when valproate was injected 1 h before the precipitating dose of naloxone. In this latter schedule, concomitant administration of gamma-vinyl-GABA failed to reduce the severity of the convulsions observed during the abstinence syndrome. These results suggest that valproate is metabolized to a compound responsible for decreased analgesia and intensified withdrawal signs.

Analgesia↗
PubMed1982

Effects of denervation on the sensitizing effect to noradrenaline induced by morphine in the vas deferens of mice treated chronically with morphine.

The acute administration of morphine to the isolated vas deferens from mice chronically exposed to this analgesic, induced a facilitatory effect on the responses of the muscle to exogenous noradrenaline. It has been suggested that this sensitizing property of morphine might reflect a dependence-like state of the vas deferens. In the present paper, the capability of met- and leu-enkephalin to substitute for morphine was studied, as well as the influence of innervation on the apparent dependence state. The contractile responses to noradrenaline and to acetylcholine were increased after the administration of morphine to the bath containing a denervated vas deferences, prepared from chronically morphinized mice. Morphine administration facilitated noradrenaline- but not acetylcholine-induced contractile effects in vas deferens isolated from mice which had been chronically treated with either morphine or morphine plus guanethidine. The presence of met- or leu-enkephalin in the isolated vas deferens from chronically morphinized mice (either intact, denervated or treated with guanethidine) failed to sensitize contractile responses to noradrenaline or acetylcholine. It is concluded that (a) the sensitizing effect induced by morphine in the vas deferens from mice chronically treated with morphine is specific for the adrenergic neurotransmitter; (b) the effect of morphine is not mimicked by opiate peptides; and (c) denervation of the vas deferens of mice treated chronically with morphine does not suppress the noradrenaline-sensitizing property of morphine.

Acetylcholine↗
PubMed1982

Sensitivity changes after morphine treatment in the mouse uterus.

The addition of morphine to a bath containing the vas deferens from chronically morphinized mice induces a facilitatory effect on noradrenaline contractile responses. This facilitatory effect of morphine has been thought to be a dependence-like effect. In the present work the possibility that a pretreatment with morphine might induce a similar effect on the contractile responses of the mouse uterus to acetylcholine and serotonin was examined. The acute effect of morphine on the uteri of untreated mice consisted in an attenuation of the responses to both substances, whereas a long term pretreatment with morphine induced a supersensitivity state. Tolerance to the depressant action of morphine on the contractile responses induced by the stimulating compounds was also observed. Acute morphine in the uteri from morphinized mice did not induce a facilitatory effect on acetylcholine or serotonin responses. Naloxone did not modify the effects of morphine in the naive or chronically treated mice. The supersensitivity state and the intensity of tolerance were unaffected by changes in the concentration of calcium in the bath medium. Caffeine or theophylline decreased the tolerance observed in the uterus from chronically morphinized mice. The attenuation of tolerance suggests that methylxanthines induce effects opposed to those of chronic morphine in the calcium distribution within the cell.

Acetylcholine↗
PubMed1981

[Lichen nitidus in children. Study of 17 cases].

Seventeen children with clinical and histological diagnosis at lichen nitidus are reported. An incidence of one case for every 882 pediatric dermatology patients was found. LN predominated in males in a 3:1 relation. The lesions usually first appeared during infancy as grouped skin colored micropapules with shiny surface. The trunk and upper limbs were the most frequently affected body segments. The histological picture was diagnostic showing a local ganulomatous infiltrate in the papillary dermis in between two rate pages and in close contact with the epidermis. No effective treatment is known. The lesions spontaneously disappeared in an average time of 18 months.

Adolescent↗
PubMed1980

Effects of glycine, beta-alanine and diazepam upon morphine-tolerant-dependent mice.

The effects in mice of glycine, beta-alanine and diazepam on the analgesic response to morphine, on the intensity of tolerance and on the physical dependence on the analgesic have been examined. The two amino acids increased the analgesic response to morphine in a dose-related manner. However, both compounds were ineffective in the analgesic test (hot plate) when administered without morphine. Diazepam was ineffective in the analgesic test and it did not alter morphine analgesia, except when administered in a high dose which decreased and analgesic response. Glycine, either in single or repeated doses, did not modify tolerance to morphine, whereas beta-alanine induced a dose-related partial antagonism, which promptly reached a plateau. Diazepam induced a small decrease in the intensity of tolerance to the analgesic. The abstinence syndrome to morphine, induced by naloxone administration to primed mice, was reduced by single doses of glycine or beta-alanine. Diazepam behaved as a weak inhibitor of the abstinence syndrome when administered at a high dose. The potentiation of morphine analgesia and the antagonism of the abstinence syndrome induced by the amino acids may be related to their hyperpolarizing action in the c.n. system. The effects of beta-alanine on morphine tolerance cannot be explained by the same mechanism.

Alanine↗
PubMed1980

Oral retinoid (Ro 10-9359) in children with lamellar ichthyosis, epidermolytic hyperkeratosis and symmetrical progressive erythrokeratoderma.

8 children with lamellar ichthyosis, 1 with epidermolytic hyperkeratosis and 5 with symmetrical progressive erythrokeratoderma were treated with a new aromatic retinoid (Ro 10-9359). Clinical improvement was dramatic. The children acquired an appearance never obtained before with other managements. The treatment had to be maintained to prevent recurrence. The tolerance to the drug was good. The side-effects were minimal and tended to disappear after several months of treatment. Our results suggest that because of its efficacy, good tolerance and easy administration, the oral retinoid Ro 10-9359 is at present the treatment of choice for the great ichthyotic disorders of children.

Child↗