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Biomedical subjects

M R Ruiz

Publications and source records attributed to M R Ruiz.

10 recordsLinked to original sources
PubMed2003

Acute immobilization stress induces clinical and neuroimmunological alterations in experimental murine cutaneous leishmaniasis.

BACKGROUND: The skin is an important component of the neuroendocrine-immune axis. Several studies have shown that stress exacerbates skin disorders, affecting the function of sebaceous glands, keratinocytes, epidermal Langerhans cells and other cells, having an impact on the pathogenesis of many immunologically associated skin diseases. In American cutaneous leishmaniasis, we have shown the importance of the epidermis as a regulatory site, with the key participation of Langerhans cells. OBJECTIVES: To analyse the effect of acute immobilization stress on Langerhans cells, substance P (SP), calcitonin gene-related peptide (CGRP) and the natural course of infection in a murine model of cutaneous leishmaniasis. METHODS: BALB/c mice, susceptible to Leishmania infection, were placed under acute stress by immobilization (confinement) for 2 or 8 h before inoculation with L. mexicana (MHOM/BZ/82/BEL21). An avidin-biotin immunoperoxidase technique was used for cell and neuropeptide identification. RESULTS: The stressed animals became more susceptible to the parasite infection, which was manifested by acceleration and exacerbation of the lesions. In addition, the stressed animals showed morphological alterations (spherical bodies and shortened dendrites) and decreased numbers of epidermal Langerhans cells, when compared with control L. mexicana-infected mice. Mice stressed for 8 h showed greater and antidromic immunoreactivity to CGRP and SP at the time of infection. Moreover, the single inoculation of parasites caused a decrease of CGRP innervation. CONCLUSIONS: Acute immobilization stress induces an immunosuppressive state that further favours Leishmania invasion in susceptible animals.

Acute Disease↗
PubMed2001

Assessment of the effectiveness of descending aortomyoplasty for nonischemic cardiac failure by means of the subendocardial viability index.

INTRODUCTION: Paraaortic or external aortic counterpulsation is been investigated as a definitive ventricular assistance in cases of terminal congestive heart failure and when heart transplantation is counterindicated. Our aims is to assess the haemodynamic effects of an descending aortomyoplasty in a biological model of congestive heart failure. MATERIALS AND METHODS: As specimens, we used 10 "Large White" pigs. Mean weight was 25,3+/-2,14 Kg. After the administration of conventional anaesthesia, dissection of the latissimus dorsi muscle was performed. Then we performed a thoracotomy at the level of the fourth intercostal space to reach the thoracic aorta. The aorta is dissected 7 centimetres from the output of the subclavia artery and it is wrapped by the dissected muscle. A cardiomyostimulator is provided in order to allow the synchronization between the diastole and the muscle contraction. The model of heart failure was provoked using Verapamil plus Propanolol i.v. RESULTS: A significant increase of the systolic and diastolic aortic pressure (54,2+/-4,05 and 27.5+/-6.77 mmHg versus 76.5+/-6.25 and 56.4+/-5.2 mmHg, p<0,001) and a significant decrease of the left ventricle telediastolic pressures were observed (12.9+/-9 versus 2.6+/-1.57 mmHg, p<0,001). An increase of the cardiac output (0.363+/-0.11 versus 0.846+/-0.08 L/min, p<0,001) and the Subendocardial Viability Index (0.968+/-0.076 versus 1.351+/-0,107, p<0,001)were observed in a model of non-ischemic heart failure. CONCLUSION: Descending Aortomyoplasty as a technique to support circulation in cases of acute heart failure, improves the parameters of ventricular function, aiding the functional recovery of the left ventricle and improving significantly cardiac output as well as diastolic and systolic cardiac pressure. In addition to this, improves the Subendocardial Viability Index in cases of acute heart failure, which indirectly reflects an improvement of the Transmural and Subendocardial Perfusion of the failing heart.

Animals↗
PubMed1995

[Factors possibly associated with the age at the onset of menopause. Multicenter study].

A transversal study was performed in 1987 to examine 9,844 postmenopausal women aging from 39 to 59 years, residents from the cities of Durango, Monterrey, Guadalajara and Leon. They had their last menstruation at least 12 months before the interview and they were not pregnant. The objective was to know if the menarche, number of deliveries, use of contraceptive methods and smoking could affect the age of menopause. A case control analysis was performed. Based on frequency distribution of the age on which the menopause appeared, cases were classified as early and late menopause when a median value minus 2 SD and plus 2 SD were found, respectively. For control subjects a median + 1 SD was selected. Two and three controls were randomly assigned for early and late menopause, respectively. In total 1,610 subjects were studied. As a measure of association it was used the odds ratio with a confidence level of 95%. It was performed an analysis of confusion and interaction of variables in this study. The most relevant results were; a significant association between smoking 15 packages of cigarettes a year with an OR of 2.31 (1.05-5.17), to have more than five pregnancies with an OR of Mantel and Haenzel of 0.51 (0.33-0.76) for the early menopause. No association with late menopause was observed. It was found that the mean age of menopause was 45.5 years + 4.5 SD (n = 9,844).

Adult↗
PubMed1988

An increment in unilateral carotid blood flow produces cerebral aneurysms in rats.

To study the effect of haemodynamic stress on cerebral aneurysm development, three groups of adult Wistar rats were used: 1) One group with ligation of the right common carotid artery; 2) One with an end-to-side common carotid artery anastomosis and 3) Another group that was sham-operated. Blood flow through the left common carotid artery was measured with an electromagnetic flow transducer (0.85 mm in diameter) in anesthetized animals. Before the experimental intervention, the mean carotid blood flow was 2.8 +/- 0.14 ml/min. Following carotid ligation the blood flow in the patent carotid artery increased 25 +/- 5% after 7 +/- 0.3 days and 37 +/- 18% after 149 +/- 23 days; whereas following carotid anastomosis, carotid blood flow increased 102 +/- 16% after 9.6 +/- 2 days and 103 +/- 35% after 169 +/- 15 days. The sham operation did not significantly affect carotid blood flow. Control values for mean arterial pressure (102 +/- 3 mmHg) and blood gases (PaO2 = 106 +/- 3.4 mmHg, PaCO2 = 38 +/- 1.2 mmHg and pH = 7.32 +/- 0.02) were similar in the three groups of rats and did not change significantly over time after the experimental procedure. Necropsy was carried out 149 +/- 15 days after the experimental intervention. No cerebral aneurysms were found in the rats with carotid ligation or which had been sham-operated, however, three of the eight rats (p less than 0.05) with carotid anastomosis presented single aneurysms in the anterior cerebral-anterior communicating arterial complex.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMedDate not supplied

Electrophysiologic changes during acute rejection of heterotopically transplanted rat hearts.

Noninvasive monitoring of heart allograft rejection was performed by electrophysiologic techniques using an implanted electrode located on the epicardial surface of the heterotopic transplanted heart of rats. R wave and slew rate determinations were performed daily in 30 syngeneic and 66 allogeneic transplants. These determinations were later compared with histopathologic studies of the transplanted hearts. R wave and slew rate values of allogeneic or rejecting hearts were found to decrease significantly compared with syngeneic or nonrejecting hearts on the days studied. This noninvasive electrophysiologic method may be a promising method for monitoring heart allograft rejection.

Abdomen↗