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Biomedical subjects

L Tamayo

Publications and source records attributed to L Tamayo.

At least 19 recordsLinked to original sources
PubMed1992

Giant pigmented nevi: clinical, histopathologic, and therapeutic considerations.

Eighty pediatric patients with giant pigmented nevi more than 20 cm in their greatest diameter are reported. The incidence was 1 in 4150 general pediatric outpatients. The mode of inheritance of giant pigmented nevi is probably multifactorial; four second-degree relatives of our patients also had large nevi, and there was a 2:1 female predominance. Satellite nevi were present in 74% and nevi in mucous membranes in 31% of the patients. Eighty-six percent of nevi were pigmented and hairy. Benign nodules were observed in 19% of the patients and plexiform overgrowths in 6%. Nevi extensively involving the extremities resulted in reduced growth of the affected limb. Electroencephalograms showed abnormalities in 20% of the patients with giant pigmented nevi involving the head and upper portion of the trunk. Malignant transformation appeared in four patients and was fatal in three of them. Management consisted of observation only in 49%, surgery in 27.5%, chemical peel in 21%, and dermabrasion in 2.5% of the patients. The mean follow-up was 4.7 years.

Follow-Up Studies↗
PubMed1992

Hypomelanosis of Ito: diagnostic criteria and report of 41 cases.

We conducted a 20-year prospective review of 41 pediatric patients with a diagnosis of hypomelanosis of Ito. No evidence pointed to hereditary transmission of the disease. Associated extracutaneous pathology was mainly of the nervous and musculoskeletal systems. Three of 19 patients had chromosomal anomalies. Hypomelanosis of Ito is a clinically well-characterized syndrome in which chromosomal instability may be a component. Criteria for its presumptive and definitive diagnosis are proposed.

Abnormalities, Multiple↗
PubMed1989

Pityrosporum ovale in infantile seborrheic dermatitis.

The presence of Pityrosporum ovale was investigated in four groups of infants age 1 to 24 months, 15 with infantile seborrheic dermatitis, 15 with infantile atopic dermatitis, 15 with other infantile dermatoses, and 15 healthy infants. Samples were taken from the scalp, face, presternal area, and inguinal area. Pityrosporum ovale was detected by smears and/or cultures in 73% of infants with seborrheic dermatitis, 33% with atopic dermatitis, 33% with other dermatoses, and 53% of healthy infants. The percentages of positive smears and/or cultures from four body sites in each patient group were 42% for seborrheic dermatitis, 20% for atopic dermatitis, 20% for other infantile dermatoses, and 23% for healthy infants. The majority of infants with positive cultures or positive direct examination for P. ovale were between 1 and 8 months of age. The organism was isolated in 28% of samples taken from the scalp, 32% from the face, 30% from the presternal area, and 15% from the inguinal area. Patients with infantile seborrheic dermatitis were treated with 2% topical ketoconazole cream for two weeks. Eleven of these children were clinically cleared and 13 became mycologically negative. Pityrosporum ovale was significantly more frequent in infants with seborrheic dermatitis than in those with atopic dermatitis, in other infantile dermatoses, or in healthy infants, both in the total number of infants with positive smears and/or cultures and in the number of positive samples per body area (P less than 0.05).

Dermatitis, Atopic↗
PubMed1989

[Pityrosporum ovale in seborrheic dermatitis in children and in other dermatoses in children].

60 children aged from one month to two years were studied: 15 presenting with childhood seborrheic dermatitis, 15 with childhood atopic dermatitis, 15 with various childhood dermatoses and 15 healthy asymptomatic children. Samples of cutaneous scales from the scalp, face, sternal area and inguinal area were taken for the purpose of determining the presence of ovale by direct microscopy examination and culture. P. ovale was found in 73% of the infants presenting with seborrheic dermatitis, in 33% of those with atopic dermatitis, in 33% of those with other dermatoses and in 53% of the healthy infants. The proportion of infants in whom all four samples were found to be positive to P. ovale was as follows: 42% for seborrheic dermatitis, 20% for atopic dermatitis, 20% for other childhood dermatoses and 23% in the healthy infants. The majority of infants with both positive microscopy and culture for P. ovale were aged one to eight months. The group presenting with seborrheic dermatitis was treated with 2% ketoconazole cream or two weeks. Clinical cure was achieved in 11; mycological examination was negative in 13. P. ovale was significantly more frequent in infants with seborrheic dermatitis than in infants belonging to the other three groups. The role of P. ovale in the pathophysiology of seborrheic dermatitis is discussed.

Child, Preschool↗
PubMed1989

[Incidence of malignant, primary and metastatic solid skin tumors at a pediatric dermatology service].

The incidence of primary and metastatic cutaneous malignant solid tumors was investigated in a pediatric dermatology department. Among 25,000 first time patients seen between 1971 and 1985, 19 had cutaneous malignant solid tumors with an annual incidence of 0.7 for every 1,000 pediatric dermatology patients. Nine cases had primary cutaneous tumors and 10 cases metastatic tumors. The majority of patients were infants (zero to two years). The tumors found were rhabdomyosarcoma, six cases; basal-cell carcinoma, four cases; neuroblastoma, three cases; malignant melanoma, two cases, squamous-cell carcinoma, dermatofibrosarcoma, atypical fibroxanthoma and myxopapillary ependymoma, one case of each. Predisposing factors for the developing of malignancy were present in 42% of patients.

Adolescent↗
PubMed1988

Calcium channel antagonists increase morphine-induced analgesia and antagonize morphine tolerance.

The influence of calcium channel blockers on morphine-induced analgesia and on tolerance to the chronic administration of the opiate was investigated in mice. The effects of a test dose of morphine were significantly increased by the administration of diltiazem, flunarizine, nicardipine and verapamil. In contrast, nifedipine induced an antagonistic effect. The calcium channel antagonists did not change the reaction time to thermal stimulation in mice (hot plate test). The administration of nifedipine, flunarizine and verapamil reduced the intensity of the tolerance induced by a single dose of morphine administered in a slow release preparation. Diltiazem induced a non-significant decrease of the process. The present results are in accordance with the known interaction of acute and chronic morphine administration with the intracellular calcium concentration in neurones of the central nervous system.

Analgesia↗
PubMed1988

Influence of adrenergic and cholinergic mechanisms in baclofen induced analgesia.

1. Baclofen induced analgesia was confirmed by means of the mouse hot plate test. 2. Physostigmine significantly increased the response to baclofen whilst neostigmine was ineffective. Baclofen analgesia was reduced by atropine. 3. The response to baclofen was increased by the administration of tolazoline, propranolol and nadolol. In contrast, the analgesic response to morphine was attenuated by the antiadrenergic drugs phenoxybenzamine, tolazoline and nadolol.

Analgesics↗
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↗