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Biomedical subjects

D Huerta

Publications and source records attributed to D Huerta.

At least 19 recordsLinked to original sources
PubMed2000

A pharmacokinetic and tolerability evaluation of two continuous subcutaneous infusion systems compared to an oral controlled-release morphine.

The pharmacokinetic profiles, safety, and tolerability of continuous subcutaneous infusion with a novel drug deliver system (the MEDIPAD system) was compared to a standard infusion pump (the CADD-Micro) and to controlled-release tablets (MS Contin) for the administration of morphine sulfate. This was a single-center, open-label, three-treatment study conducted in 24 male and female healthy volunteers. The mean age was 40.6 yr (SD = +/- 12.27). A three treatment design was chosen to compare differences between modes of administration within each subject to minimize the impact of intersubject variability: Treatment A was a continuous 48-hr subcutaneous infusion of morphine sulfate (165.6 mg at a rate of 3. 45 mg/hr) with the MEDIPAD system attached to the chest, Treatment B was a series of four oral doses of morphine sulfate (120 mg each) at 12-hr intervals, and Treatment C was a continuous 48-hr subcutaneous infusion of morphine sulfate (163.2 mg at a rate of 3.40 mg/hr) with the CADD-Micro device attached to the chest. Subjects began treatment after eligibility was established and informed consent was obtained. The primary pharmacokinetic parameters (AUC, C(max)) for the two devices were similar; 90% confidence intervals showed that the MEDIPAD system was bioequivalent to the CADD-Micro in terms of both rate and extent of morphine absorption. The mean morphine plasma concentration versus time plot suggested that plasma concentrations rise more rapidly with the MEDIPAD device than with the CADD-Micro or oral administrations. The MEDIPAD system showed mild application and injection site reactions; there were no site reactions for the CADD-Micro or oral doses. As expected nausea, somnolence, and abdominal pain occurred more frequently in the oral treatment than the two infusion devices. These data suggest that the MEDIPAD system, which is currently undergoing clinical evaluation, is an acceptable alternative to the traditional oral treatment of morphine sulfate for delivery of analgesics as it allows rapid absorption of morphine; is small, easy to use, and disposable; and achieves plasma levels that are essentially equal to other standard infusion pumps.

Administration, Oral↗
PubMed1999

Sinonasal lymphoma.

The clinical course of 49 patients with the diagnosis of non-Hodgkin's lymphoma were studied in the Department of Otolaryngology of the Hospital General de Mexico between December 1986 and March 1997. The most frequent clinical symptoms in these patients were: nasal obstruction, rhinorrhea, fever, weight loss, cervical lymph adenopathy, rhinopharyngeal tumor, ulceration on the palate and periorbital cellulitis. In 73% of the patients in this series the primary presentation was nasal. Sixty-six percent of the patients were classified as intermediate grade lymphoma according to the New Working Formulation, and 33% were in a I B state according to the Ann Arbor predominant immunotype was B cell in 63% of the cases. An extensive review of the literature is also presented.

Adolescent↗
PubMed1989

A new physiologic correction technique for re-establishment of pulmonary circulation. Experimental surgical development.

A new physiologic technique is presented for surgical correction of truncus arteriosus, pseudotruncus, transposition of the great arteries, double right ventricular outflow tract with subpulmonary ventricular septal defect and certain cases of Fallot's tetralogy. The basis of the technique are creation of a neo-right atrium, neo-pulmonary trunk, neo-right atrioventricular valve and a neo-pulmonary valve by right angular atriotomy and insertion of a homologous pericardial patch with a monocuspid valve. The pulmonary circulation is re-established by anastomosis of the neo-pulmonary trunk to the pulmonary tree. The technique was used on 26 mongrel dogs. In 14 the experiments were preliminary, to evaluate the technique's validity, and in the other 12 it was performed with extracorporeal circulation and the hemodynamic status was studied at 30 and 180 min postoperatively. The technique and its results and potential advantages are described. Clinical application is considered to be feasible.

Anastomosis, Surgical↗
PubMedDate not supplied

[Structural and functional changes in the of heart of high-performance (canoeing) athletes].

We studied two groups of healthy subjects: Group I was integrated by 13 high-performance sportsmen (10 men and 3 women), devoted to the discipline of the rowing. Group II was integrated by 16 sedentary healthy subjects. All of them were studied with a two-dimensional echocardiogram, in order to study the anatomical and functional characteristics of the heart. Both groups had similar characteristics in regard of total body area, heart rate and blood pressure, the only difference was in age. The ventricular mass and the diastolic volume were greater in athletes in spite of the fact that the dimensions and transverse thicknesses were similar, this imply a longitudinal increase of the heart size. It is possible that this form of ventricular remodeling has functional advantages. On the other hand, it was demonstrated the existence of physiological hypertrophy without disorders in diastolic function.

Adolescent↗
PubMedDate not supplied

[The thickness/radius ratio (h/r) of the left ventricle in pure mitral insufficiency].

We studied 11 patients with severe mitral regurgitation (MR). With 2-D echocardiogram we could obtain the septal and posterior wall thickness, left ventricular internal dimensions and ventricular function. With parasternal short axis view we calculate the h/r ratio (left ventricular thickness/radius). The results were compared with normal values: we found important left atrial and ventricle dilatation with significative difference from the normal values (P < 0.001), the diastolic and systolic h/r ratio was significative lower than the normal values (P < 0.005): the systolic wall stress was significative higher in relation to normal values (P < 0.001). We conclude that patients with severe (MR) initially have an important ventricular dilatation but no hypertrophy despite volume overload. The possible explanation is that in early stages of the disease, the afterload of the left ventricle is low and does not trigger the development of hypertrophy. The hypertrophy appears only when the systolic stress is high secondary to myocardial failure. The excessive dilatation of the left ventricle probably damages the myocardial fibers by excessive stretch. This mechanism probably explains the poor late surgical evolution of patients with mitral prosthesis. This we propose that the optimal surgical timing for such patients is when the systolic wall stress elevates over the normal limits, because this is an early sign of myocardial failure.

Adolescent↗
PubMedDate not supplied

[Short and long term hemodynamic effects of amiodarone in patients with hypertrophic obstructive myocardiopathy. Combined evaluation using invasive and noninvasive methods].

Amiodarone is an antiarrhythmic drug with negative inotropic effect; therefore an study of hemodynamic effects of this drug in obstructive hypertrophic cardiomyopathy was performed. Seven consecutive patients with hypertrophic cardiomyopathy were studied prospectively. Intraventricular pressure gradient was determined at rest and during the Valsalva manoeuver during left heart catheterization; traces were obtained before (control) and at 10, 20 and 40 minutes after amiodarone, 10 mg/kg of body weight, was given IV. Simultaneously a mode M echocardiogram and carotid pulse were registered, Internal diameters, ejection time, percentual shortening, systolic anterior motion of the mitral valve, and mesosystolic aortic closure were measured. Afterwards oral amiodarone was administered to the same patients for 3 months. In this chronic phase the same phono-echocardiographic parameters and isovolumetric relaxation time were measured at 6 and 12 weeks. Parenteral administration of amiodarone reduced intraventricular gradient from 48.3 to 6.2, 8.7, and 1.3 mmHg. at 10, 20 and 40 minutes (p less than 0.001); mean pressure with Valsalva decreased from 78 to 19.6, 20.4, and 22.5 mmHg. (p less than 0.001). In four patients there was a reduction of left ventricular end diastolic pressure, Ejection time percent shortening and aortic closure intensity were reduced, systolic diameter and the distance septum, forward movement increased. The maximal effect was found 40 minutes after the injection of amiodarone. In the chronic phase the negative inotropic effect returns to near control values, but there is an increase in ventricular volumes with a significant shortening of the isovolumetric relaxation time. Amiodarone IV, decreases the intraventricular gradient in obstructive hypertrophic cardiomyopathy probably by a negative inotropic influence. This action almost disappears with oral amiodarone but there is a notorious improvement of left ventricular compliance.

Adult↗
PubMedDate not supplied

[Pericardial effusion simulating a tumor. The value of Doppler color echocardiography for its differentiation].

We describe the case of a patient aged 64 with aortic valve disease and pericardial effusion. Echocardiographic evaluation showed an intrapericardial mass of about 7 cm of diameter with clotted appearance, adhered to the visceral leaf, at the level of the atrio-ventricular function. Because of this finding we performed color codified Doppler echocardiography, observing that this mass acquired a blue hue during diastole and mosaic hue at the end of the systole, realizing that this phenomenon was due to fluid retention. There are many publications about the value of echocardiography for the identification of pericardial masses and some of them show how an effusion can hide a tumor. The interest of this particular case lies in that the effusion simulated a tumor and by means of the color codified Doppler we could demonstrate that it corresponded to the stream of the pericardial fluid. During the surgical procedure the absence of the mass was corroborated.

Aortic Valve Insufficiency↗
PubMedDate not supplied

[The thickness/radius ratio (t/r) in patients with dilated and hypertrophic cardiomyopathy].

We studied 17 patients with cardiomyopathy (10 hypertrophic and 7 dilated). With two-dimensional echocardiography, we obtained a short axis view at the level of papillary muscle. We calculated the ratio between thickness (h), of ventricular wall and cavity's radius (r) in diastole and systole (h/r ratio). Hypertrophic cardiomyopathy has a high h/r ratio in diastole (inappropriate hypertrophy), hypercontractility and low and systolic wall stress. Dilated cardiomyopathy has a low diastolic h/r ratio (inadequate hypertrophy) with low contractility and elevated end-systolic, wall stress. We discuss the mechanisms and consequences of different patterns of hypertrophy on the ventricular performance.

Adult↗
PubMedDate not supplied

[The thickness/radius ratio of the left ventricle in aortic stenosis. Prognostic and therapeutic implications].

Using two-D echocardiography and cardiac catheterization we studied the performance of left ventricle in severe aortic stenosis with normal ventricular function (10 patients), and with heart failure (11 patients). With appropriate hypertrophy increased ventricular function, is found resulting in systolic wall stress normalization. When hypertrophic mechanism is unable to normalize the systolic wall stress; afterload increases with ensuing heart failure (inadequate hypertrophy). Surgical treatment in those cases reduces the afterload and increases de ventricular function. Normalization of systolic wall stress in patients with severe aortic stenosis and heart failure means irreversible myocardial damage.

Adolescent↗
PubMedDate not supplied

[Natural history of rheumatic carditis. A follow-up of more than 20 years].

In this retrospective study of 43 patients of the National Institute of Cardiology of Mexico, 20 to 35 years after the first attack of rheumatic carditis shows that the prognosis of the heart valve disease is directly influenced by the number of attacks of rheumatic fever. In fact, when patients had only one rheumatic attack the secuelae was mild mitral regurgitation (19%), without hemodynamic significance, with less proportion of mitral stenosis (15%), or aortic regurgitation (7.6%), less plurivalvular lesions (16%), or required heart surgery (15%). In the other hand, when the patients suffered three rheumatic attacks had more proportion of mitral stenosis (33%), aortic regurgitation (41%), pluryvalvular lesions (38%) and required more heart (50%). We conclude that prophylactic treatment is important in patients with chronic rheumatic heart disease.

Adolescent↗
PubMedDate not supplied

[Study of ventricular function by means of echocardiographic quantification of the thickness/radius (h/r) ratio of the left ventricle in healthy subjects].

We studied 72 healthy subjects; 31 of them were adults and 41 children. By means of two-dimensional echocardiography we obtained a short axis view at the papillary muscle level of the ratio of the thickness (h) of the ventricular wall and the radius (r) of the cavity. We analysed ventricular performance determinants (pre-load, after-load and contractility). This non-invasive method gives information similar to pressure-volume curves. Thus, we propose it for the study of left ventricular overloads.

Adolescent↗
PubMedDate not supplied

[Long-term course of infarct of the right ventricle].

The long-term evolution of 36 patients surviving the phase of hospitalization after a postero-inferior infarction with extension to the right ventricle was studied. Patients included 7 women and 29 men with a mean age of 55 years. Follow-up time averaged 39 months (range: 4 to 78 months). The evolution of acute phase was analyzed and correlated with mortality, complications and long-term evolution of functional capacity. Mortality at the end of follow-up period was 5.5%. Five patients developed another myocardial infarctions (16%). No patient manifested right heart failure; in one case tricuspid regurgitation was evident. The majority of the patients (55.5%) were in functional class I of the NYHA, while 36.6% were in class II and 8.3% in class III. We conclude that long-term mortality of those patients with right ventricular infarction is not greater than that of other patients with myocardial infarction, and that the great majority have a favorable evolution in regard of functional capacity. Impared function is generally due to left ventricular failure secondary to the severity and extension of coronary lesions. The subgroup of patients with severe right ventricular dysfunction during the acute phase of the infarction did not have a worse long-term prognosis.

Adult↗
PubMedDate not supplied

[Digital radiocardioangiography as an auxiliary method for the precise localization of zones of myocardial concentration of 99mTc-Sn(II)-pyrophosphate. Preliminary report].

A new method is introduced for the superposition of 99mTc-pyrophosphate (PiF) myocardial images on the isolated images of the radioangiocardiographic dextrophase and levophase, in order to include cardiac anatomical references for the accurate topographic localization of the PiF concentration areas. Results in two different patients are presented. In one of them, the PiF concentration was evident at the inferoseptal, inferoapical and posterolateral regions of the left ventricle. In the other, the PiF concentration was evident at the same areas than in the former plus the inferoanterior region of the right ventricle. Our project is to validate this procedure by correlating its results with those obtained through other clinical methods that detect right ventricular infarction.

Angiocardiography↗
PubMedDate not supplied

[Evaluation of the experience of the observer in the interpretation of myocardial scintillography with radioactive phosphates].

Two-hundred-and five myocardial scans with radioactive phosphates, performed in 185 patients interned at the Coronary Care Unit due to acute chest pain (147 myocardial infarcts: 58 coronary heart disease), were independently interpreted by six observers with different degrees of experience on the lectures of these kind of images (two nuclear physicians, two cardiologists, and two fellows of the Nuclear Medicine Unit). A series of six different grades of myocardial concentration of the radioactive phosphates, related to its osseous concentration were followed. Each observer reported the grade of concentration he found in each image. The fraction of myocardial infarcts and of coronary heart disease found by each observer in every grade of concentration were calculated. With these data, it was determined the optimal criterion level of each observer by which he attained the minor incidence of false negative and false positive results. Four observers found their optimal criterion level on 2F, where grades 0-2D are considered as negative, and grades 2F-4 are considered as positive. One observer found his optimal level at 2D (0-1: -; 2D-4: +) and other at 1 (0: -; 1-4: +. By using a decision matrix which relates results of the test with a binary outcome (normal, abnormal) to the actual diagnosis, also with a binary outcome (infarct, no infarct), the ratios for "sensitivity", "specificity" and "accuracy" were derived for each observer performing at his particular optimal criterion level. Our results suggests that the observer performance depends on his particular degree of experience in interpreting nuclear medical images and on his visual perception. It was concluded that it is necessary to periodically evaluate the individual optimal criterion level of the physicians in charge of the lectures of the myocardial images with radioactive phosphates, liable to shift with time in relation to the experience of the observer. The need of a more objective procedure to quantitate myocardial concentration of the radioactive phosphates is also implied.

Acute Disease↗