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Biomedical subjects

D Perez

Publications and source records attributed to D Perez.

13 recordsLinked to original sources
PubMed1992

Synthesis of lactoferrin and transport of transferrin in the lactating mammary gland of sheep.

Two iron-binding proteins, lactoferrin and transferrin, are present in ruminant milk. Lactoferrin commonly has been assumed to be a product of mammary synthesis, but the origin of milk transferrin has not been elucidated. The objective of this experiment was to study the synthesis and distribution of these two proteins in the mammary gland of sheep. Explants from lactating mammary gland of sheep have been cultured in the presence of [3H]leucine to determine rates of synthesis of lactoferrin and transferrin. After incubation, [3H]lactoferrin was found, but labeled transferrin was not. The capacity of the mammary gland to synthesize lactoferrin decreased markedly in the first 24 h of lactation. Immunohistochemical techniques were utilized to identify the locations of lactoferrin and transferrin in the mammary gland. Transferrin was found in the colostrum contained in the alveolar lumen, in the cytoplasm of the secretory cells, and in the connective tissue between the mammary acini. High concentration of transferrin was found in the basal membrane of the secretory alveolar cells, mainly in those near capillary vessels. Lactoferrin was found in the colostrum and in the cytoplasm of secretory cells with a more homogeneous distribution than transferrin. The connective tissue stained negative for lactoferrin. These results suggest that, although lactoferrin is synthesized by mammary gland of the sheep, transferrin comes from blood serum, probably by a receptor-mediated mechanism of transcytosis.

Animals↗
PubMed1990

Carbon monoxide diffusing capacity is a poor predictor of clinically significant bleomycin lung. New Zealand Clinical Oncology Group.

In a retrospective analysis, serial lung function tests from 81 patients receiving bleomycin were studied to determine the accuracy of carbon monoxide diffusing capacity (DLCO) as a predictor of clinically significant bleomycin lung. Six of 81 patients developed clinically significant bleomycin lung, and the DLCO predicted its development in only one patient (sensitivity, one of six patients; 16.7%). Respiratory symptoms and chest x-ray abnormalities were the earliest manifestations in the other five patients. Seventy-five of 81 patients did not develop clinically significant bleomycin lung, and 12 of these had major falls (greater than or equal to 35% pretreatment level) in DLCO (specificity, 63 of 75 patients; 84.0%). In eight patients, bleomycin was continued after a major fall in DLCO, and none developed clinically significant lung toxicity. In this study, the DLCO failed to predict the development of serious bleomycin lung toxicity in all but one case. Furthermore, in some patients, it would appear that bleomycin may be stopped inappropriately after low DLCO measurements. It is important to monitor for respiratory symptoms and chest x-ray abnormalities during bleomycin treatment as these will be the earliest signs of lung toxicity in most cases.

Adolescent↗
PubMed1989

Interaction between noradrenaline and diltiazem in rat isolated atria.

1. The present study describes the effects of diltiazem (DIL) on noradrenaline (NA) activity in the isolated right atria of the rat. 2. Interactions between DIL and NA showed that DIL significantly shifted the concentration-response curve of NA to the right in a concentration-dependent manner. 3. The antagonist between DIL and NA is not consistent with a competitive antagonist since the slope is significantly lower than the unity. 4. A high calcium solution (4.5 mM) significantly increased the chronotropic effects of noradrenaline. 5. These results suggest that influx of calcium through calcium antagonist sensitive channels may be involved in linking of chronotropic responses to activation of alpha 1-adrenoceptors.

Animals↗
PubMed1987

Postoperative analgesia induced by subarachnoid lidocaine plus calcitonin.

A randomized double-blind study tested the analgesic effects of subarachnoid administration of salmon calcitonin (sCT) in acute postoperative pain. Sixty patients were grouped according to type of surgery (intraabdominal, extraabdominal, and lower extremities), subdivided into those given subarachnoid lidocaine 1 mg/kg plus sCT (100 IU) or lidocaine plus saline. Pain was evaluated by a descriptive scale 3, 6, 12, 24, 48, and 72 hr after surgery, as well as by the frequency of the patients' requests for postoperative analgesics. In all instances, the sCT-treated patients had significantly less postoperative pain. Similarly, the requests for analgesics was significantly lower or absent in the sCT-treated group. Minor side effects such as nausea and vomiting, abdominal pain, and "nervousness" were observed in a small number of sCT-treated patients. In our series of 30 patients, subarachnoid administration of sCT was an effective analgesic with minimal side effects. Its safety remains to be proved by further studies.

Acute Disease↗
PubMed1987

The effects of propranolol stereoisomers on nomotopic and ectopic cardiac automaticity in the rat.

The effect of the two isomers of propranolol was tested on nomotopic and ectopic cardiac automaticity in the rat. The spontaneously beating isolated right atria of the rat was used as a model for studying the effect of these drugs on nomotopic automaticity. Ectopic automaticity was induced by local injury of the isolated right ventricle. Both dextro and levopropranolol reduce nomotopic and abolish ectopic automaticity (ID50 was 0.17 microM for d-propranolol and 0.96 microM for 1-propranolol) in the rat heart. We conclude that the membrane stabilizing activity, which is present functionally in both stereoisomers, plays a significant role in the effect of these drugs on cardiac automaticity. On the other hand, the property of competitive blocking of beta-adrenergic receptors, which mainly resides in the levoisomer of propranolol does not seem to be essential for this effect.

Animals↗
PubMed1987

Compared efficacy of quinidine, amiodarone and diltiazem on both nomotopic and ectopic automaticity in the rat heart.

The effect of quinidine, amiodarone and diltiazem have been studied on both nomotopic (isolated right atria) and ectopic automaticity (induced by a local injury in the isolated right ventricle) in the rat heart. The efficacy of these three drugs, measured by the corresponding ID25, was diltiazem greater than quinidine greater than amiodarone on atrial rate and amiodarone greater than quinidine greater than diltiazem on ectopic ventricular automaticity. A depression of isolated right atria rate (sinus node function) could be regarded as an adverse effect of the drug tested (toxicity-index). On the other hand, the reduction of ectopic ventricular automaticity by the antiarrhythmic agent is considered as desired effect (effectiveness-index). We conclude that this method might be useful to evaluate the effectiveness-toxicity ratio, as a first experimental step in the development of new antiarrhythmic drugs with a direct action on cardiac tissue.

Amiodarone↗
PubMed1985

A randomised trial of cyclophosphamide pretreatment ('priming') before short-duration chemotherapy for small cell lung carcinoma.

Forty-five patients with small cell anaplastic carcinoma of the bronchus were treated with four four-weekly courses of a combination of cyclophosphamide, vincristine and methotrexate. Randomisation was carried out to determine whether they received in addition 1 g/m2 of cyclophosphamide 1 week before the three-drug therapy. Patients with limited disease received radiotherapy after their chemotherapy. Myelosuppression was similar in the two groups, but the additional cyclophosphamide did not improve remission duration or survival. Confining the chemotherapy to four courses did not give shorter survival times to those reported in other studies.

Adult↗
PubMed1985

Trilostane therapy for advanced breast cancer.

Forty-one postmenopausal patients with advanced breast cancer have been treated with trilostane, a 3 beta D-hydrogenase delta 5-isomerase inhibitor, for periods of up to 1 year. One patient responded to trilostane and in six patients the disease was stabilized. The remaining patients failed to respond to therapy. Six patients who failed to respond to trilostane subsequently responded to other forms of endocrine therapy. It is concluded that trilostane alone is not a useful agent in the treatment of advanced breast cancer.

Aged↗
PubMed1978

Effects of sulfuric acid aerosol on cardiopulmonary function of dogs, sheep, and humans.

Submicronic aerosol of sulfuric acid (H2SO4) originates from the burning of fossil fuels and discharge of vapor from the automobile engine equipped with the catalytic converter. This study was conducted to determine whether brief exposure to this aerosol in high concentrations adversely affects the cardiopulmonary system. In all studies, submicronic aerosol of sodium chloride was used as a control. Anesthetized dogs that breathed H2SO4 aerosol in concentrations up to 8 mg per m3 showed no effects on respiratory resistance, static lung compliance, and functional residual capacity. A 4-hour exposure to H2SO4 aerosol (4 mg per m3) produced no significant changes in mechanics of breathing, functional residual capacity, pulmonary and systemic arterial blood pressures, cardiac output, heart rate, and arterial blood gas tensions. Conscious sheep that breathed H2SO4 aerosol in concentrations up to 14 mg per m3 for 20 min had no alteration of tracheal mucous velocity in an immediate 3-hour follow-up period or 5 to 10 days later. Conscious sheep that breathed H2SO4 aerosol (4 mg per m3) for 4 hours had no significant alteration of tracheal mucous velocity immediately and 2 hours thereafter. Both normal and asthmatic adults breathing H2SO4 aerosol in concentrations up to 1 mg per m3 for 10 min showed no significant alteration of lung volumes, distribution of ventilation, ear oximetry, dynamic mechanics of breathing, oscillation mechanics of the chest-lung system, pulmonary capillary blood flow, diffusing capacity, O2 consumption, and pulmonary tissue volume. No delayed effects in pulmonary function nor exacerbation of bronchial asthma were observe during a follow-up period of a few weeks. The present study indicates that single exposure to submicronic H2SO4 aerosol does not produce an immediate or a delayed adverse effect on cardiopulmonary function in anesthetized dogs, conscious sheep, and normal and asthmatic adults.

Aerosols↗
PubMed1978

Hyperimmunoglobulin E syndrome.

A 24-year old woman had the major features of the hyperimmunoglobulin E syndrome: recurrent staphylococcal skin infections (from the age of 6 months), an extremely elevated serum immunoglobulin E level (25,000 units/ml), and defective neutrophil chemotaxis. This patient also had peripheral blood eosinophilia and cutaneous candidiasis. There was a family history of asthma, but the patient herself did not have a history of asthma or hay fever, and, on examination, had no evidence of atopic dermatitis. The patient has not had any systemic infections. Results of the skin biopsy showed dermal edema and a perivascular infiltrate with eosinophils and an increased number of mast cells. The clinical spectrum of the hyperimmunoglobulin E syndrome may include atopic dermatitis, mucocutaneous candidiasis, systemic infections, and/or the features of Job's syndrome.

Adolescent↗