MR outcome parameters in multiple sclerosis: comparison of surface-based thresholding segmentation and magnetization transfer ratio histographic analysis in relation to disability (a preliminary note)

BACKGROUND AND PURPOSES: MR imaging is now widely used to monitor disease progression in patients with multiple sclerosis (MS). The purpose of this study was to explore the relationship between disability status and existing and new MR parameters in MS patients. METHODS: Forty-one patients with clinically definitive MS were studied. MR imaging included T2- and T1-weighted imaging as well as gradient-echo imaging with and without magnetization transfer contrast. We used surface-based thresholding segmentation techniques to obtain T2 and T1 lesion load, T1/T2 ratio, and several magnetization transfer ratio (MTR) lesion load parameters. MTR histographic analysis included measurements of absolute peak height (aHp), relative peak height (rHp), MTR of the peak (MTRp), mean MTR (MTRm), and MTR25, MTR50, and MTR75, relating to the integrals of the histogram at 25%, 50%, and 75%, respectively, of the total area under the curve. All MR parameters were correlated with Expanded Disability Status Scale (EDSS) score, disease duration, and patient's age. RESULTS: Using surface-based thresholding segmentation techniques, we found relatively low correlations with EDSS. T1 lesion load and T1/T2 ratios correlated most strongly. Regarding MTR histographic parameters, EDSS correlated best with rHp but only weakly with others. Similar correlations were found with disease duration, but not with age. CONCLUSION: The best MR correlations with disability were several MTR histographic parameters. Our findings may favor the use of these MR parameters over T2 lesion load to monitor disease progression in patients with MS, findings that should be explored further in longitudinal studies.     

Adenovirus-mediated gene transfer to nucleus pulposus cells. Implications for the treatment of intervertebral disc degeneration

STUDY DESIGN: In vitro and in vivo studies using a rabbit model were performed to determine the feasibility of adenovirus-mediated gene transfer to the intervertebral disc. OBJECTIVES: This study was conducted to determine whether it is possible to transfer genes to cells within the intervertebral disc by direct injection of an adenovirus and to determine the duration of gene expression obtained by this method. SUMMARY OF BACKGROUND DATA: Although growth factors have the potential to stimulate the regeneration of nucleus pulposus, sustained delivery of growth factors to a degenerated disc is clinically unfeasible with present technology. Novel approaches such as gene transfer should be investigated as possible solutions to this problem. METHODS: The lacZ marker gene was used to evaluate gene delivery to cells within intervertebral discs. For the in vitro study, cell cultures were established from the nucleus pulposus tissue of New Zealand white rabbits and infected with an adenovirus encoding the lacZ gene (Ad-lacZ). For the in vivo study, the anterior aspects of lumbar intervertebral discs were surgically exposed, and Ad-lacZ in saline solution was directly injected into the nucleus pulposus. An equal volume of saline only was injected into control discs. Expression of the transferred gene was detected by staining with 5-bromo-4-chloro-3-indolyl-beta-galactosidase (X-Gal). RESULTS: The in vitro experiments confirmed that nucleus pulposus cells were efficiently transduced by an adenoviral vector carrying the lacZ gene. In vivo injection of Ad-lacZ into the nucleus pulposus resulted in the transduction of a considerable number of cells. Marker gene expression in vivo persisted at an apparently undiminished level for at least 12 weeks. No staining was noted in control discs. CONCLUSIONS: The results show the feasibility of adenovirus-mediated gene transfer to the intervertebral disc. Expression of the marker gene persisted at least 12 weeks in vivo. This successful demonstration of exogenous gene transfer to the disc and sustained, long-term expression suggests that the adenoviral vector may be suitable for delivery of appropriate genes to the disc for the treatment of spinal disorders.     

Le vieillissement, son expression au niveau de la microanatomie et des propriétés physiques de la peau

L'aspect et les qualités physiques de la peau varient avec l'âge de l'individu. Ces propriétés dépendent de la microstructure des divers tissus, et en particulier de la couche cornée, de la couche de Malpighi, du derme adventitiel, du derme réticulaire et de l'hypoderme.
Ces caractéristiques microanatomiques et fonctionnelles peuvent être examinées en microscopie électronique à balayage sur des tissus soumis à des tensions variables.
Ageing as shown by the microanatomy and the physical properties of the skin

Summary

The aspect and the physical properties of skin vary with age. These properties depend on the microstructure of the tissues, namely the stratum corneum, the malpighian layer, the adventitial dermis, the reticular dermis and the hypodermis.
These microanatomical and functional characteristics can be observed by scanning electron microscopy on tissues under variable strain.     

Effects of acute brainstem compression on auditory brainstem response in the guinea pig

BACKGROUND: The purpose of this study was to establish the norm for parameters of auditory brainstem response (ABR) in the guinea pig and to investigate if acute brainstem compression results in significant changes to these parameters. METHODS: Thirty-six guinea pigs with positive Preyer's reflex were anesthetized. A craniectomy was performed to remove the right occipital bone and the dura mater was opened to expose the brain, cerebellum and cerebellopontine angle (CPA). A small inflatable balloon was placed into the CPA precisely and slowly. ABR was recorded before incision of the skin as a baseline value, after placement and after inflation of the balloon with water at 0.1-ml intervals. RESULTS: Five stable peaks were recorded in 27 experimental animals. When the balloon was inflated with 0.1 ml water, the absolute latency (AL) of peaks IV and V and the interpeak latency (IPL) of peaks III and IV, and IV and V were prolonged. The amplitude ratios (AR) of peaks II, III, IV and V to peak I decreased. Inflation of the balloon with 0.2 ml of water caused further elongation of ALs of peaks IV and V and decreases in each AR. When the balloon volume increased to 0.3 ml, peak V became unrecognizable and peaks III and IV showed significant elongation of AL; peaks I and II did not show significant change in ALs. Further increase of the balloon volume to 0.4 ml resulted in disappearance of peaks III, IV and V; AL of peak II was also elongated. However, the amplitude and AL of peak I remained unchanged. Similar changes were observed in IPLs. CONCLUSIONS: This study establishes the norm of parameters of ABR in guinea pigs and demonstrates that acute brainstem compression causes elongation of ALs and IPLs of peaks II, III, IV and V. This suggests that peaks II, III, IV and V come from the brainstem and that peak I is not generated from the brainstem in the guinea pig.     

Acute and chronic arsenic poisoning associated with treatment of acute promyelocytic leukaemia

Seven relapsed and/or refractory acute promyelocytic leukaemia patients were treated by arsenic trioxide (As2O3). Four patients (4/7, 57%) achieved complete remission after one to three cycles of treatment and the most common acute side-effect was fluid retention (in six patients, 86%), including weight gains and pleuro-pericardial effusions. Evident polyneuropathy compatible with chronic arsenic toxicity was noted in two of the three patients who received As2O3 maintenance therapy and one of them had marked distal muscular atrophy. We suggest that As2O3 may be a useful salvage therapy for relapsed and refractory APL patients, but the acute or chronic arsenic toxicity should be carefully monitored.     

Video-assisted minimal access in excision of left atrial myxoma

BACKGROUND: Minimal access surgery with video-assisted endoscopy has been applied to the correction of intracardiac lesions. We report our experience using this technique in surgical excision of left atrial myxoma in 3 patients. METHODS: From November 1995 to March 1997, 3 female patients, ages 45 to 80 years (mean, 62.7 years), received emergency operations for excision of left atrial myxoma. These operations were performed through a right anterior submammary minithoracotomy or right parasternal incision with the assistance of endoscopy during femoro-femoral cardiopulmonary bypass. The myocardium was protected by continuous coronary perfusion with fibrillatory arrest or cardioplegic arrest with aortic cross-clamping. RESULTS: All the tumors were excised completely through the right atrial approach. The bypass time was 92 to 148 minutes (mean, 111 minutes). The operation time was 3.2 to 4.4 hours (mean, 3.7 hours). There were no hospital deaths. Follow-up, which ranged from 6 to 19 months (mean, 10.5 months), was complete in all patients. Transthoracic echocardiographic examination showed good ventricular function without any residual tumors. Patients were found to be in New York Heart Association functional class I or II. They were satisfied with the good cosmetic healing of the incision. CONCLUSIONS: Our experience demonstrates that minimal access surgery is a technically feasible, safe, and effective procedure in surgical excision of left atrial myxoma.     

Suppression of the carbachol-activated nonselective cationic current by antibody against alpha subunit of Go protein in guinea-pig gastric myocytes

In this study, we investigated which subtype of GTP-binding protein (G protein) is related to muscarinic activation of nonselective cation (NSC) channels in gastric smooth muscle. Inward cationic current was activated by the application of 50 microM carbachol (ICCh) at a holding potential of -60 mV with the same CsCl-rich solution in both pipette and bath. The same cationic current as ICCh was slowly activated by the dialysis of guanosine 5'-O-(3-thiotriphosphate) (GTP[gamma-S]) through the pipette. Since it is known that pertussis toxin pretreatment can block ICCh, antibodies (Abs) against Galpha,i (anti-Galpha,i) or Galpha,o (anti-Galpha,o) were tested. Activation of ICCh was blocked by the addition of anti-Galpha,o. However, anti-Galpha,i Abs had no significant effect on ICCh. The expression of Galpha,o in guinea-pig gastric smooth muscle was confirmed by Western immunoblot analysis. These results suggest that Go-type protein may mediate signals from the muscarinic receptor to NSC channel in guinea-pig gastric myocytes.     

Shoulder instability

The importance of the labrum and glenohumeral ligament complex for the stability of the shoulder joint has been known since the beginning of this century. Shoulder instability may be classified into two large groups. TUBS, characterized by Traumatic, Unidirectional instability and Bankart lesion which often requires Surgery. The second group AMBRI, is characterized by Atraumatic, Multidirectional, Bilateral instability that often responds to Rehabilitation, but in case of surgery Inferior capsular shift is indicated. The high recurrence rate after primary traumatic anterior dislocation in young adults has caused an ongoing discussion about the indications for primary surgery. Anatomical reconstruction focusing on the pathoanatomy is recommended due to better results and a lower complication rate as compared to non-anatomical reconstruction that alters the normal anatomy and kinematics. The recurrence rate after arthroscopic Bankart repair is still generally higher than after open surgery but may be improved by better patient selection.