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Biomedical subjects

A Rodriguez

Publications and source records attributed to A Rodriguez.

At least 19 recordsLinked to original sources
PubMed1992

Six new cases of a caterpillar-induced bleeding syndrome.

We describe six new cases of a hemorrhagic diathesis induced by contact with Lonomia achelous caterpillars. Onset of clinical bleeding varied between a few hours and 10 days post-exposure. Laboratory coagulation tests showed prolonged PT, PTT and ThT; normal platelets and a marked decrease of fibrinogen, factor V, plasminogen and factor XIII (including its subunits A and S). Factors VII, II and alfa 2 anti-plasmin were variably affected. In addition, activation of the fibrinolytic system and the generation of a procoagulant effect could also be demonstrated. Two cases developed severe hemorrhagic diathesis and one of them died of a cerebral hemorrhage. Different aspects of this rare syndrome are discussed in relation to its complex physiopathology and the variability observed in all clinical and laboratory manifestations. Therapeutic recommendations and some possible hazards following replacement transfusions are also considered.

Adult↗
PubMed1992

Structural changes in sperm from the fiddler crab, Uca tangeri (Crustacea, Brachyura), during the acrosome reaction.

The acrosome reaction (AR) was induced in sperm from the brachyuran crustacean Uca tangeri either by mixing male and female gametes in filtered seawater or by treating the spermatozoa with the divalent cation ionophore A23187. This latter method provided a sufficient number of reacted spermatozoa to allow a detailed ultrastructural study of the AR. The process consists of two separate phases: a) initial release of the acrosomal vesicle contents, and b) further elongation of the acrosomal filament, which causes reversal of the rigid capsule limiting the acrosomal vesicle contents. The elongate acrosomal filament consists of an apical perforatorium and a basal columnar structure called here the proximal piece. The former derives from the perforatorium of the uninduced sperm stage with only small ultrastructural changes. The proximal piece forms from myelin-like membrane layers which are initially distributed all around the subacrosomal region and then accumulate in a column at the perforatorial base, thus promoting a sudden forward projection of the perforatorium. The AR in brachyurans is thought to be a passive mechanism that utilizes the negative pressure exerted on the nucleus--caused by emptying of the acrosomal vesicle--for an organized accumulation of membrane-rich material immediately behind the perforatorium, with the final result of the raising of a 3 microns long acrosomal filament.

Acrosome↗
PubMed1992

Genioglossus hemorrhage after blunt facial trauma.

We present the case of a 28-year-old man admitted to a Level I trauma center after a motorcycle crash in which he sustained blunt trauma to the face and neck, including a mandibular ramus fracture. The patient had no airway compromise on admission, but he acutely developed significant partial upper airway obstruction necessitating emergency endotracheal intubation and subsequent tracheostomy approximately 36 hours after admission. This obstruction was caused by an expanding hematoma of the genioglossus muscle. Potential causes of this complication are presented, and signs and symptoms of upper airway obstruction and airway management strategies are discussed. The etiology of traumatic upper airway obstruction is reviewed.

Accidents, Traffic↗
PubMed1992

Magnetic resonance imaging in traumatic diaphragmatic rupture: case reports.

Acute traumatic diaphragmatic rupture is usually diagnosed by plain chest x-ray studies or at laparotomy. On occasion, ancillary diagnostic procedures such as computed tomography (CT) and fluoroscopy are necessary for diagnosis. Suspected acute traumatic diaphragmatic rupture was definitively diagnosed by magnetic resonance (MR) imaging in two patients. In another three patients, MR imaging was used to rule out diaphragmatic rupture. Magnetic resonance imaging may be the ancillary diagnostic procedure of choice following equivocal chest radiographs.

Adult↗
PubMed1992

Sonography in blunt abdominal trauma: a preliminary progress report.

Evaluation of blunt abdominal trauma is clinically challenging. Diagnostic peritoneal lavage (DPL) and computed tomographic (CT) scanning have become primary diagnostic modalities. We examined the efficacy and role of ultrasonographic (US) studies in the initial abdominal evaluation of blunt trauma patients. Over an 8-month period, patients whose abdominal work-up indicated the need for DPL or CT were evaluated sonographically within the first hour after admission by trauma fellows (PGY-6) with at least 1 hour of theoretical training and 1 hour of practical training. Sonograms considered positive were those showing free peritoneal fluid or organ disruption. Hard copies of the sonograms were evaluated by a staff radiologist without knowledge of the fellows' interpretations or of DPL or CT results. Based on the fellows' interpretation of the real-time sonograms, among the first 163 patients studied were 11 true-positive, 146 true-negative, one false-positive, and five false-negative results. Sixteen patients had intra-abdominal injury documented by DPL, CT, or laparotomy. Ultrasonography was 91% sensitive in detecting the presence of hemoperitoneum. Overall, ultrasonography was 69% sensitive, 99% specific, and 96% accurate in diagnosing abdominal injury. We conclude that emergency sonography on admission can serve as a valuable adjunct to the physical diagnosis of clinically significant hemoperitoneum. It is noninvasive, portable, and accurate in determining the need for further diagnostic/surgical intervention.

Abdominal Injuries↗
PubMed1992

Body habitus as a predictor of injury pattern after blunt trauma.

The records of obese and nonobese victims of blunt trauma were compared to determine if obese individuals are predisposed to a specific injury pattern. Prospectively collected data on 6368 adults admitted to a level I trauma center over a 4-year period were analyzed. Twelve percent (743 patients) met Body Mass Index (weight/height2) criteria for obesity (greater than or equal to 30 kg/m2). The obese group was older (p less than 0.01) and had lower ISSs (p less than 0.05) and higher GCS scores (p less than 0.01). More obese patients were injured in vehicular crashes (62.7% vs. 54.1% [p less than 0.01]). The obese victims were more likely to have rib fractures, pulmonary contusions, pelvic fractures, and extremity fractures and less likely to have incurred head trauma and liver injuries (p less than 0.05). Obese people injured in vehicular crashes had a similar injury pattern with no difference in seating position, direction of impact, seat belt use, and ejection.

Accidents, Traffic↗
PubMed1992

Retinal detachment after refractive surgery for myopia.

Refractive surgery has been used widely in some countries for the last 20 years for the correction of myopia. Radial keratotomy and keratomileusis, the most common procedures, may concur with retinal detachment. A total of 14 eyes in 12 patients, 7 after keratomileusis and 7 after radial keratotomy, which had either asymptomatic or symptomatic retinal breaks, subclinical and clinical rhegmatogenous retinal detachments, or both, are discussed here. Five eyes were treated with either laser photocoagulation or cryopexy alone, seven eyes with a scleral buckling procedure, one eye with vitrectomy, and one eye was not operated on. At the final follow-up examination, anatomic reattachment had been achieved in 12 of 14 eyes (85.7%). Visual acuity improved in 3 eyes (21.4%), remained stable in 9 eyes (64.3%), and was worse in 2 eyes (14.3%). The scleral buckling procedures used in the repair of retinal detachment induced refractive changes by modifying axial length and corneal curvature, with recurrence of myopia and astigmatism. Myopia increased a mean of -3.00 diopters in 6 of 7 eyes (86%). Myopic astigmatism power changed a mean of -1.00 diopter in 5 eyes (71%), and the astigmatic axes shifted in 3 eyes (43%). This situation could be prevented with an early peripheral search for and treatment of peripheral retinal degenerative pathologic changes, by avoiding encircling bucklings, or by using alternative methods of treatment.

Adult↗
PubMed1992

Discriminative criteria for Neisseria meningitidis isolates that are moderately susceptible to penicillin and ampicillin.

The prevalence of Neisseria meningitidis isolates that are moderately susceptible to penicillin and ampicillin has increased very quickly in Spain; the current prevalences in our hospital are 48.4 and 55.6%, respectively. We studied the reliability of the disk diffusion method for discriminating between fully susceptible (MIC, less than or equal to 0.06 microgram/ml) and moderately susceptible (MICs, 0.12 to 1.0 microgram/ml) isolates. Thirty-eight isolates (12 Pen(s) Amp(s), 18 Penr Ampr, and 8 Pen(s) Ampr) were assayed by the disk diffusion and plate dilution methods by use of disks of 1, 2, 5, and 10 U of penicillin, 2 and 10 micrograms of ampicillin, and 1 microgram of oxacillin on Mueller-Hinton agar with or without 5% sheep blood. Breakpoints were generated, and their discriminative values were determined with a collection of 195 meningococcal strains isolated consecutively from cerebrospinal fluid or blood. None of the strains produced beta-lactamase. Penicillin- and ampicillin-susceptible strains (MIC, less than or equal to 0.06 microgram/ml) had oxacillin inhibition zones of greater than or equal to 11 mm on blood agar. Moderate susceptibility to ampicillin and penicillin was suggested by an inhibition zone of less than or equal to 10 mm around the 1-microgram disk and an inhibition zone of less than or equal to 26 mm around the 2-U penicillin disk. We conclude that discrimination between fully susceptible and moderately susceptible populations of N. meningitidis can be accomplished by the disk diffusion method by use of Mueller-Hinton agar plus 5% sheep blood with the 1-microgram oxacillin disk (which is especially suited for screening methods) and the 2-U penicillin disk. The lack of an oxacillin inhibition zone indicates moderate susceptibility to either penicillin or ampicillin or both.

Ampicillin↗
PubMed1992

Aromatase activity and estradiol in human breast cancer: its relationship to estradiol and epidermal growth factor receptors and to tumor-node-metastasis staging.

PURPOSE: The present report attempts to clarify whether there is a relationship between aromatase activity (ARAC) and estradiol (E2), hormonal receptors, E2 receptor (ER), and epidermal growth factor receptor (EGFR), as well as with tumor stage and histopathology in human breast cancers. MATERIALS AND METHODS: We studied 225 breast carcinomas, 67 of which were premenopausal and 158 postmenopausal. In each sample, ARAC, EGFR, ER, and E2 were quantified. ARAC was quantified by Thompson and Siiterii's method, EGFR was quantified with a two-point assay method using radioactive iodine (125I)-EGF as ligand, and ER was measured by the Scatchard method using 3H-E2. E2 was quantified by radioimmunoassay in the diethylether tumor extract. RESULTS: ARAC was found in 64% of the cancers studied. There is a strong direct association between ARAC and tumor size in postmenopausal patients (P = .001). In the postmenopausal group, the proportion of ARAC-positive (ARAC+) tumors is significantly higher among ER-positive (ER+) than ER-negative (ER-) ones (P less than .001). ER+ tumors also have significantly higher levels of E2 than do ER- ones (P less than .0001); similarly, ARAC+ tumors have significantly higher levels of E2 than do ARAC- ones (P less than .0001). There is a significant multiple linear correlation between the log of the levels of ARAC, ER, and EGFR and the log of tumor E2 (P less than .0001). The correlation coefficients obtained show that ARAC and ER have a positive effect on tumor E2. CONCLUSION: The results obtained suggest the importance of tumor ARAC in the tumoral levels of E2 and reinforce the possible biologic significance of tumor ARAC, especially in postmenopausal breast carcinoma patients.

Adult↗
PubMed1992

Suppressive effect of tetrahydrocannabinol on specific T cell subpopulations in the thymus.

The effects of THC (delta-9-tetrahydrocannabinol) on thymocytes from adult BALB/c mice were investigated following in vitro stimulation with the T cell mitogen Concanavalin A (Con A). Con A treatment resulted in a decrease in the relative percent of L3T4+/Ly2+ cells (double positive; immature) with a concomitant increase in the percent of Ly2 cells (suppressor/cytotoxic). No change in the percent of L3T4 cells (helper) occurred. In addition, Con A stimulation resulted in an increase in the absolute number of Ly2 cells, with no change in number of L3T4 cells. Stimulation with the mitogen led to an increase in fluorescence intensity (indicative of relative number of markers) of Ly2 markers on Ly2 single positive cells as well as on L3T4+/Ly2+ cells. There was a moderate mitogen induced increase of L3T4 markers, but only on L3T4 single positive cells. Exposure to THC resulted in a definitive suppressive effect on Con A induced thymus cell proliferation. The suppression was primarily evidenced in the single positive Ly2 subpopulations. Since the thymus is the source of immunocompetent lymphocytes to the secondary lymphoid organs, it seems plausible that marijuana negatively affects maturation of these cells in the developing individual.

Animals↗
PubMed1992

The RBE-LET relationship for rodent intestinal crypt cell survival, testes weight loss, and multicellular spheroid cell survival after heavy-ion irradiation.

This report presents data for survival of mouse intestinal crypt cells, mouse testes weight loss as an indicator of survival of spermatogonial stem cells, and survival of rat 9L spheroid cells after irradiation in the plateau region of unmodified particle beams ranging in mass from 4He to 139La. The LET values range from 1.6 to 953 keV/microns. These studies examine the RBE-LET relationship for two normal tissues and for an in vitro tissue model, multicellular spheroids. When the RBE values are plotted as a function of LET, the resulting curve is characterized by a region in which RBE increases with LET, a peak RBE at an LET value of 100 keV/microns, and a region of decreasing RBE at LETs greater than 100 keV/microns. Inactivation cross sections (sigma) for these three biological systems have been calculated from the exponential terminal slope of the dose-response relationship for each ion. For this determination the dose is expressed as particle fluence and the parameter sigma indicates effect per particle. A plot of sigma versus LET shows that the curve for testes weight loss is shifted to the left, indicating greater radiosensitivity at lower LETs than for crypt cell and spheroid cell survival. The curves for cross section versus LET for all three model systems show similar characteristics with a relatively linear portion below 100 keV/microns and a region of lessened slope in the LET range above 100 keV/microns for testes and spheroids. The data indicate that the effectiveness per particle increases as a function of LET and, to a limited extent, Z, at LET values greater than 100 keV/microns. Previously published results for spread Bragg peaks are also summarized, and they suggest that RBE is dependent on both the LET and the Z of the particle.

Animals↗
PubMed1992

Influences of witnessed affect on information processing in children.

Children between the ages of 5 and 10 years watched a videotape of a child having a routine medical exam. Embedded within the scenes were systematic variations of depicted facial affect shown by doctor and child. Measures were taken of autonomic reactions and information-processing errors in response to positive, neutral, and negative affective cues. For 5-6-year-olds, processing errors were greatest in the negative affect condition. Additionally, peak increases in heart rate (HR) and skin conductance level (SCL) were demonstrated by 5-6-year-olds in response to negative affect shown by the witnessed child; increases in HR were in turn predictive of processing errors. Older children (9-10 years) showed trends reflecting reduced processing errors in response to witnessed negative affect. It was suggested that younger children respond to salient threat cues with a "defensive" response pattern that is relatively adaptive at younger but not older ages.

Affect↗
PubMed1992

Retroperitoneal hematoma after blunt trauma.

We reviewed retrospectively 233 consecutive patients with retroperitoneal hematoma (RPH) resulting from blunt trauma. This study group represented 2.9 per cent of all admissions for blunt trauma and 13 per cent of all admissions for blunt abdominal trauma. Motor vehicle accidents predominated as the cause of injury. Fifty-five per cent of the patients had fractures of the pelvis. Laparotomy was the primary method used in diagnosing RPH (73 per cent). The RPH was located in zone I in 14 per cent of patients, zone II in 37 per cent, zone III in 46 per cent and zone IV in 3 per cent. The RPH was explored in 35 per cent of all patients. Major vessels were the most common organ system injured (21 per cent) in patients with zone I RPH. The kidney was the most commonly injured organ (27 per cent) in patients with zone II RPH. Injury of either the pancreas or duodenum in 14 per cent of patients with right-sided zone II RPH indicates the need for careful evaluation of those organs at operation. Patients with zone III RPH associated with fractures of the pelvis should be explored only rarely--when main iliac vascular injury is suspected (4.6 per cent in this series). Otherwise, a systematic approach using external fixator devices and angiographic embolization should be used. The over-all morbidity and mortality rates of 59 and 39 per cent, respectively, emphasize the need for aggressive resuscitation, rapid control of hemorrhage and a multidisciplinary approach to the management of these patients.

Abdominal Injuries↗
PubMed1992

Injuries of the abdominal aorta from blunt trauma.

Blunt injuries of the abdominal aorta are rarely reported in the literature. If left undiagnosed, these injuries may have catastrophic consequences. Four patients with blunt abdominal aortic lesions, identified in the authors' trauma registry, are presented in this report, along with a discussion of the pertinent literature to illustrate clinical management techniques. The mechanisms of injury include motor vehicular crashes (most frequent) with or without seatbelt use, abdominal blows, falls, and abdominal crush injuries. The spectrum of aortic lesions ranges from simple contusion or intramural hematoma to intimal disruption, false aneurysm, or frank rupture. Aortography should be performed in all stable patients with suspected aortic injury. All central-medial retroperitoneal hematomas discovered at laparotomy for blunt trauma should be explored after proximal and distal control of the aorta is obtained. Strict adherence to these principles, maintenance of standard vascular technique, and aggressive, expeditious resuscitative evaluation may improve survival.

Adult↗