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Biomedical subjects

J Ramirez

Publications and source records attributed to J Ramirez.

At least 37 records · Page 2Linked to original sources
PubMed1987

Gastroplasty and fundoplication for complex reflux problems. Long-term results.

Between 1964 and 1984, 430 patients with complex reflux problems were managed by a modified Collis gastroplasty and partial fundoplication. The indications for selecting the addition of gastroplasty were as follows: (1) obvious acquired shortening due to peptic esophagitis and stricture, and (2) subtler degrees of acquired shortening frequently encountered in cases that required reoperation and in patients with massive sliding hiatal hernia. The addition of gastroplasty in this second group obviates the risk of even minimal tension on the repair. Follow-up is complete in 382 patients (90%), and extends 1-20 years. Two hundred fifty patients have been followed up for 5 or more years and 101 patients for more than 10 years. Results were classified as follows: good: asymptomatic, or inconsequential symptoms requiring no therapy; fair: improved, but with symptoms and/or endoscopic findings requiring intermittent therapy; poor: unimproved or worse. Patients are divided into four categories, and the results are tabulated below (see Table 2). The best results are obtained in patients with acquired shortening due to esophagitis with and without stricture who have had no prior antireflux surgery and have no associated primary motor disorder. The proportion of unsatisfactory results is almost tripled (20% fair or poor) after reoperation after one or more failed antireflux procedures. When reflux esophagitis and stricture are associated with a primary motor disorder, only half of the patients have a good result sustained throughout long-term follow-up.

Adenocarcinoma↗
PubMed1986

Usual interstitial pneumonitis is a T-cell alveolitis.

Usual interstitial pneumonitis (UIP) is an idiopathic inflammatory disorder that produces scarring of the lung parenchyma. We studied open-lung biopsies of 13 patients with UIP using immunohistological staining and monoclonal antibodies. T lymphocytes (Leu 4+) accounted for 59% of cells in the alveolar septal infiltrates in UIP and OKT8+ cells accounted for the majority of T lymphocytes in most cases. OKM1+ granulocytes comprised a smaller percentage (14%) of the alveolar infiltrates. Granulocytes were most frequent within cystic airspaces and inflamed small airways. Class II HLA (Ia) antigens were expressed on lymphocytes, macrophages, endothelial cells, and alveolar type II cells in lungs with UIP. This study demonstrates that altered immunoregulatory subsets are present in the lungs of patients with UIP and suggests the possibility that activated T cells may play a role in the pathogenesis of this disorder.

Adult↗
PubMed1986

Traumatic aneurysms of the descending thoracic aorta.

From July 1979 to December 1985 we observed 51 patients with traumatic lesions of the descending thoracic aorta. Twenty-nine had acute ruptures, mostly accompanied by multiple injuries, and 27 had to be operated upon immediately. Twenty-two patients (19 males, 3 females) had chronic traumatic aneurysms of the descending thoracic aorta (more than six weeks after trauma). Mean age at the time of trauma was 24 years. Mean age at time of surgery was 36.5 years. Twelve patients were symptomatic. All were treated surgically. At surgery, complete aortic disruption was found in 15 patients and partial rupture in seven. We did not use aortic shunting of any kind, only aortic cross-clamping. Hypertension was controlled by intravenous drug infusion. The ruptured aortic segment was replaced in all cases by prosthetic Dacron graft. There were no operative deaths. One patient (age 77) died 11 weeks after surgery from multiple organ failure. One case of postoperative paraplegia was observed. This patient recovered almost completely from his neurological deficit.

Adult↗
PubMed1985

The effect of diffusion on the binding of membrane-bound receptors to coated pits.

We have formulated a kinetic model for the primary steps that occur at the cell membrane during receptor-mediated endocytosis. This model includes the diffusion of receptor molecules, the binding of receptors to coated pits, the loss of coated pits by invagination, and random reinsertion of receptors and coated pits. Using the mechanistic statistical theory of nonequilibrium thermodynamics, we employ this mechanism to calculate the two-dimensional radial distribution of receptors around coated pits at steady state. From this we obtain an equation that describes the effect of receptor diffusion on the rate of binding to coated pits. Our equation does not assume that ligand binding is instantaneous and can be used to assess the effect of diffusion on the binding rate. Using experimental data for low density lipoprotein receptors on fibroblast cells, we conclude that the effect of diffusion on the binding of these receptors to coated pits is no more than 84% diffusion controlled. This corresponds to a dissociation rate constant for receptors on coated pits (k-) that is much less than the rate constant for invagination of the pits (lambda = 3.3 X 10(-3)/s) and a correlation length for the radial distribution function of six times the radius of a coated pit. Although the existing experimental data are compatible with any value of k-, we obtain a lower bound for the value of the binding constant (k+) of 2.3 X 10(-2)(micron)2/s. Comparison of the predicted radial distributions with experiment should provide a clear indication of the effect of diffusion on k+.

Coated Pits, Cell-Membrane↗
PubMed1985

Effects of beta-pinene on yeast membrane functions.

The effects of beta-pinene on yeast cells were studied. This terpene inhibited respiration with glucose or ethanol as the substrate. The inhibition depended on the ratio of the terpene to the amount of yeast cells; for a fixed concentration of pinene, inhibition decreased as the amount of yeast cells increased. Pinene also inhibited the pumping of protons and K+ transport, but this inhibition was more marked with with ethanol than with glucose as the substrate, indicating the mitochondrial localization of the inhibition. The studies on isolated mitochondria showed a series of effects, starting with the disappearance of the respiratory control and deenergization of the organelles and followed by an inhibition of respiration at higher concentrations of the terpene. The effect on respiration could be localized to the cytochrome b region of the electron transport chain. No effect could be detected on the activity of ATPase. The effects can be ascribed to a localization of pinene on membranes which was also accompanied by a decrease in the fluorescence polarization of diphenyl hexatriene, probably meaning an increase in the fluidity of the membrane, localized preferentially to the mitochondria.

Adenosine Triphosphatases↗
PubMed1978

Echocardiographic diagnosis of ruptured aortic valve leaflet in bacterial endocarditis.

Aortic valve rupture, secondary to aortic valve endocarditis, was diagnosed echocardiographically and closely followed preoperatively. The ruptured left coronary cusp of the aortic valve was seen as dense irregular echoes, located anteriorly during ventricular diastole, and protruding into the left ventricular outflow tract in an otherwise normally appearing aortic valve. These echocardiographic findings, when correlated with changes in the clinical status of the patient, prompted immediate cardiac catheterization and aortic valve replacement. Early echocardiographic detection of abnormal aortic cusps and variation from normal aortic root echo features should alert the physician to proceed to cardiac catheterization, and aortic valve replacement if necessary.

Adult↗
PubMed1978

Determination of fetal maturity from the measurement of the sedimentary fraction of the amniotic fluid (amniocrit).

A simple technique is described for evaluating foetal maturity. This consists in measuring the sedimentary fraction of the amniotic fluid (amniocrit). The amount of sediment, expressed in percent of the total liquid volume varies between 0.33% at 36 weeks of amenorrhea and about 2.22% at 40 weeks. These values are correspond to arithmetical means. The differences between pre-term and term pregnancy are highly significant (p less than 0.001). The mean at 32--36 weeks of amenorrhea is 0.27, and at 37--41 weeks is 1.45. A close correlation between gestational age and the fraction of sediment in amniotic fluid is shown in Fig. 1. The correlation coefficient was 0.726. This technique of measuring the sediment combines simplicity and reliability and can be employed where minimal resources are available, and in rural hospitals. The feasibility of using this procedure in institutions with limited resources is emphasized.

Amniotic Fluid↗
PubMed1976

Indoramin in the treatment of hypertension: a placebo controlled trial.

The effect of the alpha-blocker indoramin was studied in a 4-week double-blind comparative trial with placebo in 39 patients with mild to moderate essential hypertension. Dosage of indoramin was individually adjusted and ranged from 125 mg to 200 mg daily. Indoramin produced a significantly greater reduction in diastolic blood pressure than placebo, and 9 (56%) out of 16 patients attained diastolic pressures of 90 mmHg or less. Heart rate, haematology and blood biochemistry were unaffected by treatment with indoramin, and there were no E.C.G. changes. Nine out of 19 patients on indoramin complained of side-effects. These were generally not troublesome, although 3 patients withdrew because of severe tiredness or weight gain.

Ambulatory Care↗