Cerebral auditory plasticity and cochlear implants

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.

[Radio-anatomic study of the angle of origin of dysplastic renal arteries]

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.

Endovascular Doppler guide wire in renal arteries. Correlation with angiography in 20 patients

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.

Dynamic magnetic resonance imaging of the female pelvis: radio-anatomy and pathologic applications. Preliminary results

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.

[CT and MRI features of a pseudo adrenal lesion: subcardial diverticulum]

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.

Adjacent cooperation of proteins on DNA are not representative of long-distance interactions

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).

Computed tomographic appearance of three intrapulmonary lymph nodes

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.

Antiproliferative effects and mechanism of action of SCH 56592 against Trypanosoma (Schizotrypanum) cruzi: in vitro and in vivo studies

We have investigated the antiproliferative effects of SCH 56592, a new experimental triazole, against Trypanosoma (Schizotrypanum) cruzi, the etiological agent of Chagas' disease in Latin America. SCH 56592 blocked the proliferation of the epimastigote form of the parasite in vitro at 30 nM, a concentration 30- to 100-fold lower than that required with the reference compounds ketoconazole and itraconazole. At that concentration all the parasite's endogenous sterols (ergosterol, 24-ethyl-cholesta-5,7,22-trien-3 beta-ol, and its 22-dihydro analogs), were replaced by methylated sterols (lanosterol and 24-methylene-dihydrolanosterol), as revealed by high-resolution gas chromatography coupled with mass spectrometry. This indicated that the primary mechanism of action of the drug was inhibition of the parasite's sterol C-14 alpha demethylase. Against the clinically relevant intracellular amastigote form, grown in cultured Vero cells at 37 degrees C, the MIC of SCH 56592 was 0.3 nM, again 33- to 100-fold lower than that of ketoconazole or itraconazole. In a murine model of acute Chagas' disease, SCH 56592 given at > or = 10 mg/kg of body weight/day for a total of 43 doses allowed 85 to 100% survival and 90 to 100% cure of the surviving animals, as verified by parasitological, serological, and PCR-based tests, while ketoconazole given at 30 mg/kg day allowed 60% survival but only 20% cure. In a murine model of chronic Chagas' disease, SCH 56592 was again more effective than ketoconazole, providing 75 to 85% protection from death, with 60 to 75% parasitological cures of the surviving animals, while no parasitological cures were observed with ketoconazole. The results indicate that SCH 56592 is the most powerful sterol biosynthesis inhibitor ever tested against T. cruzi and may be useful in the treatment of human Chagas' disease.

[Treatment using percutaneous arterial embolization of post-traumatic priapism in children]

High flow rate priapism was diagnosed in a 14-year-old adolescent 5 days after a fall onto the perineum. Highly selective embolization of the 2 internal pudendal arteries was performed with gelatin (SPONGEL). Rapid resolution of the priapism as well as return of normal erection were observed within 48 hours. Doppler ultrasound revealed a high flow rate and identified the side of the traumatized artery. Endovascular embolization allows effective treatment of traumatic arteriocavernous fistula.

[Regression of a focal nodular hyperplasia after stopping oral contraceptives]

The complete regression of a focal nodular hyperplasia of the liver with typical MRI patterns 5 years after withdrawal of oral contraceptives was observed. Effects of oral contraceptives on this tumor's evolution and appropriate imaging by MRI are discussed.

Steroids in the hemolytic uremic syndrome

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.

Cure of renovascular hypertension by percutaneous occlusion of a large idiopathic renal arteriovenous fistula. Case report

Percutaneous balloon occlusion of a large hypertensive idiopathic renal arteriovenous fistula is reported. A lumbar thrill was noted in a 52-year-old hypertensive woman. Intravenous digital substraction angiography identified the lesion. After arteriographic assessment a percutaneous embolisation was performed with a releasable balloon positioned on a coaxial micro-catheter. Immediate post-procedural angiographic control demonstrated complete occlusion with a small segmental area of renal hypoperfusion. The lumbar thrill disappeared. Normalisation of the blood pressure was noted two days later and confirmed eight months later. Persistent occlusion of the fistula was angiographically confirmed, whereas the area of renal hypoperfusion had partially decreased. Releasable balloon percutaneous embolisation appears to be a safe alternative to surgery in the treatment of large renal arteriovenous fistulas.

[Angioplasty of renal artery stenoses before surgical treatment of subrenal abdominal aortic lesions]

PURPOSE

To evaluate the results of the association of a percutaneous transluminal renal angioplasty before a surgical revascularization of the infra-renal aorta.

PATIENTS AND METHODS

Percutaneous transluminal angioplasty of one (n = 12) or two (n = 2) renal arteries have been performed in 14 patients (11 hypertensive and one with azotemia), 2 to 240 days (mean 54) before infra-renal aortic surgery (aneurysms: 8, occlusive disease: 6).

RESULTS

15 of the 16 dilatations were completely technically successful (residual stenosis less than 20%), with one groin hematoma treated medically. Mean duration of the surgical intervention were 137 minutes (occlusive disease) and 147 minutes (aneurysm). In the post-operative course were noted resolutive infections in two patients, and one death because of myocardial infarction. At the end of the follow-up (3 to 60 months, mean 32), all of the 13 patients alive had improved in terms of vascular disease. Hypertension was improved for 2 patients, stable for 10, worse for 1. Creatinine serum level was stable for 12 patients, and the renal insufficient was worsened.

CONCLUSION

Combined percutaneous transluminal renal angioplasty and aortic revascularization seems to be reliable and safe; it can be an alternative to a simultaneous aortic and renal revascularization, notably for high-risk patients.

Cure of short- and long-term experimental Chagas' disease using D0870

Chagas' disease, a protozoan infection by the kinetoplastid Trypanosoma cruzi, constitutes a major public health problem in Latin America. With the use of mouse models of both short- and long-term forms of the disease, the efficacy of D0870, a bis-triazole derivative, was tested. D0870 was able to prevent death and induced parasitological cure in 70 to 90 percent of animals, in both the short- and long-term disease. In contrast, currently used drugs such as nifurtimox or ketoconazole prolonged survival but did not induce significant curing effects. D0870 may be useful in the treatment of human long-term Chagas' disease, a condition that is currently incurable.

Treatment of chronic, nonhealing abdominal wound in a liquid environment

A 66-year-old woman with an abdominal wound caused by infected synthetic mesh had failed to heal in spite of many surgical attempts to close the wound. A sealed transparent vinyl chamber was glued to the periphery of the wound and antibiotics in high concentrations (up to 2,500 times the minimum inhibitory concentration) were delivered through the chamber. The wound fluid in the chamber was used for analysis of microbial activity, concentration of residual antibiotics, and growth factor activity. After 10 weeks of treatment, the wound was closed and has not recurred in 24 months.