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Biomedical subjects

A Rodriguez

Publications and source records attributed to A Rodriguez.

At least 343 records · Page 19Linked to original sources
PubMed1983

Right ventricular outflow obstruction secondary to right-sided tamponade following myocardial trauma.

A case of isolated tamponade of the right side of the heart, seen as an abrupt change in the cardiac silhouette and as right ventricular outflow obstruction following myocardial trauma, is presented, along with a review of the English-language literature on delayed postoperative tamponade and loculated pericardial effusion. The importance of a low, fixed cardiac output and nonspecific physical findings in suggesting the clinical diagnosis is emphasized. The absence of many of the classic signs and symptoms of pericardial tamponade is noted, as is the possibility of unusual changes in the appearance or function of the heart in the presence of a loculated effusion. Finally, the differential diagnosis and the results of a variety of diagnostic techniques are discussed.

Adult↗
PubMed1983

Role of the ovary in the regulation of sex hormone binding globulin and its contribution to peripheral levels of androstenedione.

In order to assess the role of the ovary in the regulation of the levels of the sex-hormone-binding-globulin (SHBG) and its contribution to peripheral levels of androstenedione, three subject groups were studied: 10 normally menstruating women, 8 postmenopausic women, and 8 postmenopausic ovariectomized women. A basal venous blood sample was drawn between 8:00 to 9:00 h from all subjects in the latter two groups. The blood samples were drawn from the normally menstruating women on days 7, 14, 21 and 28 of their cycles. The following determinations were made in each sample: oestradiol, progesterone, testosterone, androstenedione SHBG, FSH and LH. It was concluded that: 1) SHBG does not vary during the menstrual cycle, nor there are significant differences between postmenopausic and castrated women, and 2) androstenedione levels in castrated women are significantly different from both postmenopausic and normally menstruating women.

Adult↗
PubMed1983

Osteoarticular abnormalities and orthopedic complications in children with chromosomal aberrations.

Chromosome abnormalities may result in a great number of osteo-articular anomalies. Little documentation concerning these anomalies is available. The main orthopedic problems encountered in 67 children with chromosomal abnormalities are reported here. Patients should be evaluated at regular intervals in order to detect osteoarticular involvement. Gradual deterioration results in disabling conditions which are difficult to manage. Orthopedic management should be mainly preventive. It's purpose is to delay or to avoid the onset of disabling complications.

Adolescent↗
PubMed1983

Traumatic rupture of the pericardium.

Patients with traumatic rupture of the pericardium rarely survive to reach a hospital. Ten cases from the Maryland Institute for Emergency Medical Services Systems and 132 previously published cases are reviewed. Patients were usually men who were victims of violent thoracic trauma. The median age was 40 years. Half of the patients had left pleuropericardial tears; tears of the diaphragmatic pericardium, right pleuropericardium, and superior mediastinal pericardium were less frequent. Associated injuries of the heart or left hemidiaphragm were common. Pericardial rupture was usually discovered during surgical exploration for other indications, but physical or radiographic signs were occasionally present. Repair is indicated for most pericardial tears to prevent herniation of the heart or abdominal viscera.

Abdominal Injuries↗
PubMed1982

Molecular and cellular radiobiology of heavy ions.

Quantitative studies at the BEVALAC have demonstrated some of the physical and radiobiological factors that promise to make accelerated heavy ions important for the therapy of cancer. The measured physical dose-biological effect relationships allow the safe and effective delivery of therapeutic schedules of heavy ions. Among the charged particle beams available, carbon, neon and helium ions in the "extended Bragg peak mode" have optimal physical and biological effectiveness for delivery of therapy to deep seated tumors. The depth-dose profiles of these beams protect intervening and adjacent tissues as well as tissues beyond the range of the particles. For the treatment of hypoxic tumors, silicon and argon beams are being considered because they significantly depress the radiobiological oxygen effect in the region of the extended Bragg ionization peak. The depth-effectiveness of the argon beam is somewhat limited, however, because of primary particle fragmentation. Silicon beams have a depth-dose profile which is intermediate between that of neon and argon, and are candidates to become the particle of choice for maximizing high LET particle effects. Heavy accelerated ions depress enzymatic repair mechanisms, decrease variations of radiosensitivity during the cell division cycle, cause greater than expected delays in cell division, and decrease the protective effects of neighboring cells in organized systems. Near the Bragg peak, enhancement of heavy particle effects are observed in split dose schedules. Late and carcinogenic effects are being studied. With the newly developed Repair-Misrepair theory we can quantitatively model most observations.

Animals↗
PubMed1982

Glucose and lactate kinetics and interrelations in an antarctic bird (emperor penguin).

The isotope single-injection method was used to investigate the glucose and lactate kinetics and the interrelationships between the glucose and lactate pools in fasting emperor penguins. In these remarkably fast-resistant birds, mean lactate concentration, replacement rate, pool, space, and transit time were 1.5 mmol.1-1,53 mumol.min-1.kg-1, 900 mumol.kg-1, 60% of body mass, and 17 min, respectively. Mean glucose concentration, replacement rate, pool, space, and transit time were 20 mmol.1-1, 23 mumol.min-1.kg-1, 4,300 mumol.kg-1, 24% of body mass, and 196 min, respectively. Maximum conversions of lactate into glucose and of glucose into lactate were 29 +/- 2.9% and 75.5 +/- 4.2%, respectively, which indicates that lactate is an effective gluconeogenic precursor and a major fate of glucose metabolism in fasting penguins. The lactate replacement rate and incorporation into glucose were related to the plasma lactate concentration, which suggests that the rate of formation of glucose from lactate is dependent on the availability of lactate. The glucose replacement rate and reduction into lactate were related with the plasma glucose concentration, suggesting that the rate of lactate formation from glucose is dependent on the plasma glucose concentration. These data suggest that in the fasting emperor penguin glucose and lactate availability is capable of regulating the rate at which these substrates are utilized and interconverted. To our knowledge, this is the first evidence for such regulatory capacities in birds.

Animals↗
PubMed1982

The value of technetium99m pyrophosphate scanning in the diagnosis of myocardial contusion.

Twelve patients who sustained significant blunt chest trauma and had abnormal electrocardiographic changes unrelated to hypotension, hypoxia, or pre-existing myocardial disease were studied prospectively during a one-year period. The patients were divided into two groups on the basis of serum creatine phosphokinase (CPK)/MB isoenzyme concentrations: Group A (six patients) had normal CPK/MB isoenzymes (less than 8 IU), and Group B (six patients) had elevated CPK/MB isoenzymes (greater than 8 IU). All patients underwent cardiac scanning with technetium99m pyrophosphate. All studies were interpreted as normal. These data suggest that technetium99m pyrophosphate scanning is not a reliable adjunctive test to confirm myocardial contusion in patients with significant blunt trauma of the chest. However, the diagnosis of myocardial contusion in such patients can be established by the presence of abnormal electrocardiographic changes associated with an elevation of the serum CPK/MB isoenzyme concentration.

Adolescent↗
PubMed1982

Recognition of intra-abdominal injury in blunt trauma victims. A prospective study comparing physical examination with peritoneal lavage.

The accuracy of initial physical examination and peritoneal lavage in detecting intra-abdominal injury was assessed in 221 consecutive blunt trauma victims. Of the patients, 121 had negative peritoneal lavages, with one false result, and 100 had positive peritoneal lavages, including six false results and two injuries not requiring surgical correction. Hemoperitoneum occurred in 32 of 71 patients with a depressed sensorium and in 29 of 54 patients with thoracic injury. Twenty-eight of 120 patients with absent bowel tones and 20 of 100 patients with abdominal guarding or rigidity had negative peritoneal lavages. Among the 150 conscious, responsive patients there was a high incidence of false-positive and false-negative abdominal findings on physical examination. Hemoperitoneum was detected in four clinically negative patients. Significant error accompanies the initial abdominal examination and clinical assessment in the blunt trauma victim. In contract, open diagnostic peritoneal lavage is a sensitive and highly accurate test for blunt intraperitoneal injury. We believe peritoneal lavage is the single best test for intra-abdominal injury and should be performed in th majority of patients with such injuries.

Abdominal Injuries↗
PubMed1982

Peritoneal lavage in children and adolescents with blunt abdominal trauma.

The major cause of death in children is trauma. Although prompt recognition of blunt abdominal injury is essential, physical examination is an inexact means of establishing the diagnosis. One hundred thirty-five blunt trauma victims under 16 years of age underwent open diagnostic peritoneal lavage over a three-year period. The overall accuracy rate of peritoneal lavage was 95.5 per cent, which included true-negatives (65.9%), false-positives (4.5%), and true-positives (29.6%). These were no false-negative results. Of 40 patients with intra-abdominal injuries, five (12.5%) did not require surgical correction. Open diagnostic peritoneal lavage is the single best test for detecting serious intra-abdominal injury following blunt trauma in children and adolescents.

Abdominal Injuries↗
PubMed1981

Interaction of selectively spin-labeled 70S ribosomes with tRNAPhe. An electron paramagnetic resonance study.

70S ribosomes from Escherichia coli, selectively spin labeled on the SH groups of proteins S18, S12, S21, S17, and L27, were used to study the formation of the tertiary complex ribosome-poly(U)-tRNAPhe. Most of these ribosomal proteins are located in the region of binding of tRNA. The electron paramagnetic resonance observable structural change suggests a loosening of the ribosome structure upon binding of the tRNA molecule.

Ascorbic Acid↗
PubMed1981

A comparative study of flap survival rates in end-to-end and end-to-side microvascular anastomosis.

This study compared free flap survival rates following end-to-end and end-to-side arterial anastomoses. A groin flap was transferred to the anterior cervical region in 40 rats. There were 20 rats in each experimental group. The end-to-side group was further divided into subgroups depending on the angle of the anastomosis, which was either 60 degrees or 90 degrees. The results revealed no significant difference in the survival rates between any of the groups (which varied between 80 and 85 percent). A discussion of previous experimental work and the significance of these results has been presented. The advantages and disadvantages of end-to-side anastomoses have also been discussed.

Animals↗
PubMed1980

Interaction of 70 S ribosomes from Escherichia coli with spin-labeled N-Cbz-Phe-tRNAPhe. An electron paramagnetic resonance study.

Two selectively spin-labeled Cbz-Phe-tRNAsPhe, one at position s4U8 and the other at position U33, have been used to study the dynamics of tRNA-ribosome interaction in the presence of poly(U) and factors washable from ribosomes. Upon binding to the ribosome, the correlation time of the spin label at position s4U8 decreases markedly while the same parameter for the label in the anticodon increases. The presence of poly(U) is not a prerequisite condition for the EPR spectral changes observed but larger variation occurs in the presence of factors washable from ribosomes. No variation in the correlation time is observed if uncharged spin-labeled tRNAPhe (on the s4U8 residue) is used in these experiments. Most of the ribosome-bound spin-labeled Cbz-Phe-tRNAPhe are puromycin-reactive, and consequently, the observed effect is manifested mainly at the ribosomal P site. These observations seem to suggest that the interaction between the N-blocked aminoacyl residue on the tRNA and the ribosome results in a conformational change on the tRNA, possibly involving tertiary interactions in a region close to s4U8. The role that the amino acid at the 3'-end can possibly play on this structural change is discussed.

Electron Spin Resonance Spectroscopy↗