Biomedical subjects
Publications and source records attributed to N Perez.
Airbag-induced injury fatality is increasing in frequency. We present the case of a 6-year-old passenger who sustained a fatal atlanto-occipital dislocation associated with airbag deployment in a low-speed motor vehicle crash. The current literature regarding airbag fatalities and methods to ameliorate airbag-induced injury are reviewed.
OBJECTIVES: To determine the value of color flow imaging in the prenatal differentiation of solid placental masses protruding from the fetal surface of the placenta. METHODS: Seven pregnancies in which a large solid mass was seen on the fetal surface of the placenta were prospectively studied. Color flow imaging was used to identify vessels within the mass and the prenatal ultrasound finding correlated with placental pathology. RESULTS: Postpartum examination of the placenta revealed four cases of chorioangioma, two cases of subchorionic thrombohematoma and one case of subamniotic hematoma. Prenatal ultrasound using color flow imaging correctly identified all cases of placental chorioangioma by the demonstration of blood flow within the mass. Conversely, absence of blood flow signals was invariably documented in both cases of subchorionic thrombohematoma and in the single case of subamniotic hematoma. Among the four cases of chorioangioma, two developed complications requiring delivery. No complications were noted in cases of avascular placental masses in this series. CONCLUSIONS: Color Doppler ultrasound plays an important role in the prenatal evaluation of solid placental masses. This technique allows the identification of those cases at increased risk of pregnancy complications which need close monitoring throughout gestation.
This article presents information on considerations involved in setting up and conducting fellowship training programs in emergency medicine (EM) for physicians from other countries. General goals for these programs are to assist in providing physicians from other countries with the knowledge and skills needed to further develop EM in their home countries. The authors report their opinions, based on their cumulative extensive experiences, on the necessary and optional structural elements to consider for international EM fellowship programs. Because of U.S. medical licensing restrictions, much of the proposed programs' content would be "observational" rather than involving direct "hands-on" clinical EM training. Due to the very recent initiation of these programs in the United States, there has not yet been reported any scientific evaluation of their structure or efficacy. International EM fellowship programs involving mainly observational EM experience can serve as one method to assist in EM development in other countries. Future studies should assess the impact and efficacy of these programs.
We report changes in the cochlear nuclei (CNs) after 3 months of bilateral auditory deafferentation and simultaneous unilateral implantation of a dummy auditory brain stem implant (ABI) in 6 nonhuman primates (Macaca fascicularis). These specimens were compared to CNs of 9 controls and 7 bilaterally deafferented animals without implantation. The ABI array consists of 3 platinum electrodes mounted on a silicone pad with the back side covered with Dacron. No migration of the ABI was observed. All deafferented animals showed astrocytic reorganization in the CNs. Histologic changes consisted of superficial reactions around the implant, with formation of fibrillar bundles of fusiform cells, and the presence of giant cells close to the Dacron. Other findings were related to surgical trauma. The dummy ABI did not itself provoke serious adverse reactions in the CNs. Our observations support the possibility of ABI reimplantation surgery.
PURPOSE: To evaluate long-term results of infrapopliteal percutaneous transluminal angioplasty (PTA) for limb salvage. MATERIAL AND METHODS: A retrospective study of 71 consecutive infrapopliteal PTAs in 49 patients with rest pain (n = 20) or ulceration (n = 29) was conducted. In 18 patients, surgical minor amputation or debridment was also performed. RESULTS: Technical success was achieved in 45 patients. Four failures necessitated 2 amputations. One patient died in the postoperative course. Global morbidity rate was 16%, including minor complications in 5 patients and major vascular complications in 3 patients. After technical success during the follow-up (median duration 21 months), restenoses occurred in 4 patients, of whom 3 had a successful re-PTA (clinical success rate 72%). Survival, primary patency, secondary patency and limb salvage rates were, respectively, 75%, 81%, 88% and 87% after 3 years. The only positive predictive factor for primary patency was the presence of diabetes mellitus. CONCLUSION: Infrapopliteal PTA is a safe and effective procedure, allowing good patency and limb salvage rates with low mortality and morbidity.
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PURPOSE: Evaluate the MR sensibility for detection and localisation of ACTH-secreting microadenomas of the pituitary gland. PATIENTS: and method. The MRI studies of the pituitary gland, performed before transsphenoidal surgical exploration, about 14 patients who present clinical and biological signs of Cushing disease, were reviewed retrospectively. We have always used unenhanced sagittal and coronal spin-echo T1 sequences, and coronal T1 after injection of gadolinium (1 Tesla). RESULTS: The global sensibility for detection of an adenoma was 100% (84 to 92% when the lesional localisation was considered). The injection of gadolinium increased the sensibility of 38 to 42% according the readers. 7 to 14% of the lesions were isointense after injection. The estimation of lesional size after injection was the nearer to the surgical results. The indirect sign most frequently seen (35.7 to 64.3%) was focal bulging of the sellar diaphragm. The only differences between the different radiologists, statistically significant, concerned the lesional size before injection and location of the lesion in the sagittal plane. CONCLUSION: This study confirmed the good sensibility of contrast-enhanced MRI in detection of ACTH-secreting microadenomas. The anatomo-radiological correlations are nevertheless incomplete.
Previous animal research and clinical experiences in humans suggest the existence of an auditory critical period in language acquisition. We review the literature and present the changes within the cochlear nuclei in bilaterally deafferentated adult non-human primates. We also present and analyse the results of 98 prelingually deaf children and teenagers who underwent a cochlear implantation at the University of Navarra. Patients received a Nucleus 22 or 24 multichannel cochlear implant (CI). They were grouped in five categories according to their age at surgery. Performance is compared with a control group of 58 postlinguals. Only early-implanted prelingual children (before 6 years of age) achieved a complete open-set speech recognition, even with better performance than postlinguals. These results clearly demonstrate the existence of a period of high neural auditory plasticity within the first 6 years of life. The introduction of auditory stimulation with a CI can not restore the loss of neural plasticity out of this period. Prelingual children under 6 years of age should receive a CI as soon as there is a reliable diagnosis of bilateral sensorineural hearing loss.
Dynamic MRI of the pelvis was performed in 16 young nulliparous, normally continent women. The examinations were performed in the dorsal decubitus position. Using Turbo-Flash scans (acquisition time: 2.1 sec), sagittal images were obtained at rest and with maximal pelvic straining. The sacral promontory-subpubic (PSP) and the subpubic-subsacral axes (SPSS) measured respectively 80.5 degrees and 30 degrees in relation to the horizontal plane, without a statistically significant difference between rest and straining. A marked deformation of the posterior wall of the bladder was observed in 13 cases and the bladder neck was frontally deformed in 10 cases. With straining, the base of the bladder did not descend beyond 15 mm below the SPSS, and the cervix stayed at least 14 mm above the SPSS. These were established as the normal criteria for pelvic assessment. 20 multiparous patients (mean age 65 years), referred for urinary stress incontinence and/or prolapse, were investigated using the criteria previously established. The PSP, SPSS, and vaginal angle measured 80.95 degrees, 30.57 degrees, and 69.69 degrees respectively in relation to the horizontal. No statistically significant difference was detected between straining and rest conditions. The angle of the uterus in relation to the horizontal was 57.36 degrees at rest and 65.90 degrees in straining with a difference that was statistically significant. In six patients, the base of the bladder descended more than 1.5 cm while straining and in seven patients the cervix descended at least 1.4 cm below the SPSS while straining, both statistically significant differences. Overall, between our control and study populations, there were no significant differences between PSP and SPSS measured on straining and at rest. However, differences were detected in the vaginal angle, bladder-base position, and cervical position. These results suggest the potential substitution of MRI for colpocystography.
RATIONALE AND OBJECTIVES: To evaluate the feasibility of endovascular Doppler recording in renal arteries and to compare the reliability of Doppler parameters for detection of renal artery stenosis. METHODS: The authors examined 36 renal arteries in 20 patients with a 0.018" endovascular flow wire. Peak systolic velocity and the renal artery-to-aortic peak were measured in the main renal artery. From intrarenal waveforms, acceleration, acceleration time, and the renal resistive index were obtained. Spectral analysis with consensus scoring of early systolic peak was also performed. RESULTS: Twelve significantly stenosed renal arteries and 26 normal renal arteries were examined with the Doppler guide wire, without complications. Peak systolic velocity was the only parameter significantly different in renal artery stenosis (P = 0.037). Peak systolic velocity also differed significantly between hypertensive and normotensive patients. Tardus parvus was specific for severe renal artery stenosis. CONCLUSIONS: Endovascular Doppler is a safe and accurate method for the determination of velocity measurements and may be useful during percutaneous renal artery revascularization.
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Gastric diverticula are rare. The retroperitoneal site of subcardial diverticula may be suggestive of a left adrenal mass on CT and MR. The authors report two cases. Radiological demonstration of a communication with the stomach confirms the diagnosis.
PURPOSE: To compare the angulation at the origin of dysplastic renal arteries compared to atherosclerotic renal arteries, in order to improve the technique for percutaneous transluminal angioplasty of FMD. MATERIALS AND METHODS: Retrospective analysis of 40 aortograms in patients who underwent renal angioplasty for dysplastic stenosis, with comparison with 45 control aortograms (with or without atherosclerotic lesions of the renal arteries). The angle of implantation of the renal arteries was measured relative to the aortic axis in the frontal plane, taking into account only the angulation of its proximal segment. We identified three types of kidneys with regard to their position relative to the renal artery ostium. RESULTS: The angle of implantation of dysplastic renal arteries is significantly sharper compared with the control group (63.8 degrees vs 80.9 degrees, p = 0.0001), irrespective of the side. The angulation did not correlate with the position of the kidney or the direction of the renal artery, suggesting a congenital origin. CONCLUSION: The angle of implantation of the dysplastic renal arteries relative to the aortic axis in the frontal plane is sharper than the angle measured in non dysplastic renal arteries.
To determine whether steroids could be of clinical benefit in the treatment of the hemolytic uremic syndrome (HUS), we conducted a randomized, double-blinded, placebo-controlled trial of methylprednisone (5 mg/kg per day in four oral doses over 7 days), in children with HUS during the acute phase. Ninety-two patients with typical HUS (47 receiving placebo and 45 receiving steroids) were investigated for neurological, hematological, and nephrological variables. There were no differences between groups in the number of convulsive episodes or transfusion requirements during the hospital stay. Serum creatinine levels were slightly increased on day 10 in the placebo group compared with the steroid group (P = 0.06) and declined significantly between days 1 and 10 only in the steroid group (P = 0.001). In the 51 patients with anuria (24 placebo, 27 steroids), median serum creatinine levels were reduced in the steroid group compared with the placebo group on the 10th day (P = 0.01). Differences in median days of oliguria [11.5 versus 8 (P = 0.28)], anuria [5 versus 7 (P = 0.20)], and dialysis [12 versus 10 (P = 0.26)] for the placebo and the steroid group respectively were not significant. Our data suggest that oral steroids are not able to modify hematological, neurological, or nephrological clinical parameters during the acute phase of childhood HUS, even though they do seem to be associated with a more rapid decline in serum creatinine levels.
Intrapulmonary lymph nodes are rare lesions, usually appearing as small subpleural nodule (coin lesion), at or under the height of the carina. Computed tomography (CT) is very accurate in their detection. Three observations are reported.
The cI repressor of bacteriophage lambda is better-fitted to the proximal interactions in which it naturally takes part than to the long-distance cooperative interactions on DNA for which it has become representative. The first observation in support of this statement is the ambiguity of an untypical DNAase I footprint which has become a diagnostic for DNA circularisation (and thus for the capacity of the protein to control expression at a distance). However, it was also observed without effective DNA looping when lac repressor binds to nearly contiguous sites. Additionally, the surface of interaction between the two dimers seems to be more important than the one commonly admitted (via some contacts between the flexible arms), the biological function of the repressor is lost when the sites are separated and loops have not been observed for large separation of the sites. In fact, naturally distant interactions can conform to shorter distances, as an intrinsic property of DNA looping. On the contrary, interactions which are naturally optimised for contiguity are generally constrained to proximity. Alternative protein-protein contacts are generally responsible for this situation (cf. CRP versus NRI in Escherichia coli).