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Biomedical subjects

J Contreras

Publications and source records attributed to J Contreras.

At least 73 records · Page 4Linked to original sources

Delayed hypersensitivity to enoxaparin.

A 65-year-old woman experienced immediate itchy erythematous patches at the subcutaneous injection sites of sodium enoxaparin. An erythematous and infiltrated 40 x 20 mm lesion on the abdominal wall could be observed at the site of enoxaparin injection when she was referred to our clinic 48 h after injection. Lesions subsided spontaneously within 1 week. She had been on this treatment 1 and 3 years before without any adverse reaction. To clarify the nature of the reaction, epicutaneous tests with sodium enoxaparin, calcium nadroparin and calcium heparin were performed, all with negative results. Skin prick test with sodium enoxaparin was also negative. Biopsy of the cutaneous lesion showed spongiotic dermatitis, strongly suggesting a delayed hypersensitivity mechanism. We report here on a new case of delayed hypersensitivity to enoxaparin. Being female, overweight and having prolonged application of the drug were suggested risk factors present in our patient. Biopsy was essential for diagnosis. Although type IV hypersensitivity reactions to enoxaparin are rare, we should start to suspect this condition in order not to underdiagnose it.

Aged↗

[Study of various factors that could have an impact on the treatment with erythropoietin of hemodialysis anemia].

Several factors influence the efficacy of the action of human recombinant erythropoietin during treatment of anaemia in haemodialysis patients. We carried out a six-month prospective study of 23 stable patients who had been on haemodialysis for at least one year to attempt to evaluate those factors modifying the dose of the hormone to attain a similar haematocrit, such as use or not of angiotensin converting enzyme inhibitors, hepatitis C virus positive or negative, age older or younger than 60 years, acquired cystic kidney disease or not, and sex. The patients were treated with subcutaneaous erythropoietin for over a year to attain a haematocrit of 35%, intravenous iron to reach plasma ferritin levels > 250 ng/ml and a transferrin saturation index > 20%, folic acid and group B vitamins. Parameters studied included age, time and duration of haemodialysis, Kt/V, albumin, haematocrit, erythropoietin in U/kg/week, intact PTH, hepatitis C virus, PCR of the hepatitis C virus, transaminases, ferritin, transferrin saturation index, folic acid, vitamin B12, and aluminium. No statistically significant differences were seen between the patients with and without hepatitis or in age or acquired cystic kidney disease and sex in the hormone dose given to achieve similar levels of haematocrit. Higher doses of erythropoietin were necessary in those patients treated with antihypertensive agents (71 +/- 25 vs 44 +/- 25 U/kg/week; p < 0.05). There were no differences between groups in factors known to cause resistance to the action of the hormone. The most important conclusions from this study concern the cost-benefit relation of treating hypertensive patients on haemodialysis with angiotensin converting enzyme inhibitors and erythropoietin.

Age Factors↗

Importance of albumin in cross-reactivity among cat, dog and horse allergens.

Different allergenic proteins have been involved in cross-reactivity among animals. Albumins seem to be cross-sensitizing allergenic components. The aim of this study was to assess the importance of albumin as a cross-reactive allergen in patients sensitized to cat, dog and horse. One hundred and seventeen patients sensitized to cat were tested for IgE reactivity using skin prick tests and RAST assays with cat, dog and horse hair/dander extracts and their purified albumin extracts. RAST-inhibition studies were carried out to assess cross-reactivity among cat, dog and horse and among their purified albumins. It was found that 22% of patients exhibited specific IgE to cat albumin; 41% of patients sensitized to cat were also sensitized to dog and horse. Out of these patients, 21% had IgE to three albumins and 17% to two. Reciprocal inhibitions were observed among cat, dog and horse albumins and also among cat, dog and horse hair/dander extracts, using in the latter experiment sera from patients not sensitized to albumins. IgE binding to horse extract was inhibited 30% by its homologous albumin and IgE binding to cat and dog extracts in almost 15% by their respective albumins. It was concluded that albumins from these three animals share some epitopes that account for the cross-reactivity observed in around one-third of patients sensitized to cat, dog and horse. Nevertheless, more than 50% of specific IgE that cross-reacts among these three animals is directed to allergens other than albumin.

Albumins↗

[Solitary rectal ulcer syndrome].

The solitary rectal ulcer syndrome is an infrequent entity consisting of a rectal lesion, caused by straining during defecation; it is characterized by specific histological changes. The condition is most frequent in adults between 30 and 50 years of age, but a few pediatric cases have been reported. Five patients (4 boys) are presented. All suffered from moderate rectal bleeding, straining, tenesmus and mucous discharge. One of them had clinical and endoscopic evidence of rectal prolapse. On defecography all children showed failure of pelvic floor relaxation during straining. Endoscopic evaluation showed single or multiple ulcers in four patients and a nodular fibrotic lesion in one. The histopathology of the rectal mucosa revealed replacement of the stroma of the lamina propria by collagen, lack of orientation of smooth muscle fibers and considerable hyperthopy of the muscularis mucosae. Medical treatment was satisfactory in four patients, one case required transabdominal rectopexy for relief of his symptoms. The most appropriate form of treatment has not been determined, but surgery should be used when prolapse is a prominent clinical feature. Greater awareness of this condition will lead to more frequent diagnosis.

Adolescent↗