Vanishing white matter: a leukodystrophy due to astrocytic dysfunction

VWM is one of the most prevalent leukodystrophies with unique clinical, pathological and molecular features. It mostly affects children, but may develop at all ages, from birth to senescence. It is dominated by cerebellar ataxia and susceptible to stresses that act as factors provoking disease onset or episodes of rapid neurological deterioration possibly leading to death. VWM is caused by mutations in any of the genes encoding the five subunits of the eukaryotic translation initiation factor 2B (eIF2B). Although eIF2B is ubiquitously expressed, VWM primarily manifests as a leukodystrophy with increasing white matter rarefaction and cystic degeneration, meager astrogliosis with no glial scarring and dysmorphic immature astrocytes and increased numbers of oligodendrocyte progenitor cells that are restrained from maturing into myelin‐forming cells. Recent findings point to a central role for astrocytes in driving the brain pathology, with secondary effects on both oligodendroglia and axons. In this, VWM belongs to the growing group of astrocytopathies, in which loss of essential astrocytic functions and gain of detrimental functions drive degeneration of the white matter. Additional disease mechanisms include activation of the unfolded protein response with constitutive predisposition to cellular stress, failure of astrocyte‐microglia crosstalk and possibly secondary effects on the oxidative phosphorylation. VWM involves a translation initiation factor. The group of leukodystrophies due to defects in mRNA translation is also growing, suggesting that this may be a common disease mechanism. The combination of all these features makes VWM an intriguing natural model to understand the biology and pathology of the white matter.     

Ramipril for the prevention and treatment of cardiovascular disease

OBJECTIVE: To evaluate the effectiveness of ramipril in the prevention and treatment of cardiovascular disease and determine its need for inclusion on a formulary. DATA SOURCES: A MEDLINE and PubMed database search was conducted (1987-May 2002). Only journals written in the English language were selected for review. DATA EXTRACTION AND STUDY SELECTION: Articles reporting the use of ramipril in humans were evaluated. Emphasis was placed on randomized, controlled trials assessing efficacy. DATA SYNTHESIS: Ramipril is an angiotensin-converting enzyme (ACE) inhibitor that exerts its effects through inhibition of the renin-angiotensin-aldosterone system. It exhibits a safety profile that is similar to that of other ACE inhibitors and is comparable in cost to the majority of the available agents. Clinical trials have proven the effectiveness of ACE inhibitors in the treatment of hypertension, heart failure, and nephropathy. Ramipril, however, is the only ACE inhibitor currently approved for the prevention of cardiovascular events in high-risk patients without evidence of left-ventricular dysfunction or heart failure, based on the results of the HOPE (Heart Outcomes Prevention Evaluation) trial. Whether this effect is specific to ramipril has yet to be proven. This article emphasizes the major trials involving ramipril including the AIRE (Acute Infarction Ramipril Efficacy), REIN (Ramipril Efficacy in Nephropathy), and HOPE trials. CONCLUSIONS: Although similar to other ACE inhibitors in many aspects, it cannot be assumed that the benefits shown with ramipril in the HOPE trial are a class effect. Ongoing trials should help to clarify this matter. Until this time, current evidence justifies the inclusion of ramipril on a formulary.     

Outcome of Local Excision of Rectal Carcinoma

PURPOSE This study was designed to determine the results of patients with rectal adenocarcinoma treated with local excision.METHODS A retrospective, chart review was conducted for all patients treated with local excision for rectal adenocarcinoma from 1984 to 1998.RESULTS Sixty-four patients were retained for analysis. The median follow-up was 37 (range, 9–125) months. There were 15 local failures with a median time to local failure of 12 months. Seven patients were salvaged with further operation (4 by repeat local excision, 4 by abdominoperineal resection, and 1 by low anterior resection). The incidence of local recurrence increased with advancing stage of the carcinoma (T₁, 13 percent; T₂, 24 percent; T₃, 71 percent), histologic grade of differentiation, (well, 12 percent; moderately, 24 percent; poorly, 44 percent), and margin status (negative, 16 percent; close (within 2 mm), 33 percent; positive, 50 percent). Sixteen percent of carcinomas 3 cm failed compared with 47 percent for carcinomas > 3 cm. Nine percent (1/11) of T₂ patients treated with adjuvant radiation therapy recurred locally compared with 36 percent (5/14) without radiation therapy. Three of four T₃ patients who received radiation therapy failed locally compared with two of three who did not. Using the Kaplan-Meier method, the overall survival at five years was 71 percent, and disease-free survival was 83 percent. Actuarial local failure was 27 percent and freedom from distant metastasis was 86 percent. The sphincter preservation rate was 90 percent at five years.CONCLUSIONS Local excision alone is an acceptable option for well-differentiated, T₁ carcinomas, 3 cm. Adjuvant radiation is recommended for T₂ lesions. The high local recurrence rate in patients after local excision of T₃ lesions with or without adjuvant radiotherapy would mandate a radical resection.Reprints are not available.Poster presentation at the meeting of The American Society Colon Rectal Surgeons, Boston, Massachusetts, June 24 to 29, 2000.     

Applications of accelerator MS in pediatric drug evaluation

Accelerator MS (AMS) provides a novel method for obtaining and analyzing pharmacokinetics and pharmacodynamics in children. This paper reviews the scientific and ethical rationale for AMS in pediatric trials, the regulatory framework and general considerations with some specific examples of pediatric clinical trials using AMS. Microdosing in the context of this article refers to studies using a negligible amount (nanocuries) of (14)C as tracer, and AMS as a quantitative technique. The technology is by no means a panacea for the deficiency in pediatric clinical research; however, it lessens the challenges and provides the most quantitative tool for pediatric pharmacology studies.     

Lamotrigine in patients with epilepsy and comorbid depressive symptoms

PurposeThis open-label study evaluated the antidepressant qualities of lamotrigine (LTG) in people with epilepsy.MethodsEligible patients exhibited low to moderate depressive symptoms and required a change in antiepileptic drug (AED) therapy, but were excluded if they had a major depressive disorder (MDD). Lamotrigine was added onto a stable AED regimen, and self-report instruments were administered to evaluate changes in mood states. Evaluations were conducted at baseline, at the end of 19 weeks of adjunctive treatment, and 36 weeks following conversion to monotherapy.ResultsOne hundred and fifty-eight patients with epilepsy participated; 96 patients completed adjunctive treatment, and 66 patients completed monotherapy. Intent-to-treat analyses for all instruments showed improvement in depression scores after adjunctive LTG treatment. Improvement was maintained for those converted to monotherapy.ConclusionsThese data suggest that LTG may have antidepressant activity for patients with epilepsy and comorbid low to moderate depressive symptoms, and warrant a randomized controlled trial for validation.     

Corticotropin-releasing factor in the dorsal raphe nucleus increases medial prefrontal cortical serotonin via type 2 receptors and median raphe nucleus activity

Interactions between central corticotropin-releasing factor (CRF) and serotonergic systems are believed to be important for mediating fear and anxiety behaviors. Recently we demonstrated that infusions of CRF into the rat dorsal raphe nucleus result in a delayed increase in serotonin release within the medial prefrontal cortex that coincided with a reduction in fear behavior. The current studies were designed to study the CRF receptor mechanisms and pathways involved in this serotonergic response. Infusions of CRF (0.5 μg/0.5 μL) were made into the dorsal raphe nucleus of urethane-anesthetized rats following either inactivation of the median raphe nucleus by muscimol (25 ng/0.25 μL) or antagonism of CRF receptor type 1 or CRF receptor type 2 in the dorsal raphe nucleus with antalarmin (25–50 ng/0.5 μL) or antisauvagine-30 (2 μg/0.5 μL), respectively. Medial prefrontal cortex serotonin levels were measured using in-vivo microdialysis and high-performance liquid chromatography with electrochemical detection. Increased medial prefrontal cortex serotonin release elicited by CRF infusion into the dorsal raphe nucleus was abolished by inactivation of the median raphe nucleus. Furthermore, antagonism of CRF receptor type 2 but not CRF receptor type 1 in the dorsal raphe nucleus abolished CRF-induced increases in medial prefrontal cortex serotonin. Follow-up studies involved electrical stimulation of the central nucleus of the amygdala, a source of CRF afferents to the dorsal raphe nucleus. Activation of the central nucleus increased medial prefrontal cortex serotonin release. This response was blocked by CRF receptor type 2 antagonism in the dorsal raphe. Overall, these results highlight complex CRF modulation of medial prefrontal cortex serotonergic activity at the level of the raphe nuclei.     

Genetic and epigenetic alterations of the EGFR and mutually independent association with BRCA1, MGMT,and RASSF1A methylations in Vietnamese lung adenocarcinomas

Genetic and epigenetic alterations importantly contribute to the pathogenesis of lung cancer. In the study, we measured the frequency and distribution of molecular abnormalities of EGFR as well as the aberrant promoter methylations of BRCA1, MGMT, MLH1, and RASSF1A in Vietnamese lung adenocarcinomas. We investigated the association between genetic and epigenetic alteration, and between each abnormality with clinicopathologic parameters. Somatic EGFR mutation that was found in 49/139 (35.3%) lung adenocarcinomas showed a significant association with young age, female gender, and non-smokers. EGFR overexpression was identified in 82 tumors (59.0%) and statistical relationships with EGFR or BRCA1 methylation but not EGFR mutation. In addition, EGFR, BRCA1, MGMT, MLH1, and RASSF1A methylations were found in 33 (23.7%), 41 (29.5%), 46 (33.1%), 28 (20.1%), and 41 (29.5%) cases of a total of 139 lung adenocarcinomas, respectively. The RASSF1A methylation was found to be linked to the smoking habit. Methylations in MGMT and RASSF1A were also found to correlate with metastasis status. Furthermore, the distribution of EGFR mutation and that of BRCA1, MGMT or RASSF1A methylation were significantly exclusive in lung adenocarcinomas. The main finding of our study demonstrate that epigenetic abnormalities might play a critical role for the lung tumorigenesis in patients with smoking history and metastasis, and partly affect the predictive value of EGFR mutations through blocking expression due to promoter EGFR hypermethylation. Mutually exclusive distribution of genetic and epigenetic alterations reflects differently biological characteristics in the etiology of lung adenocarcinomas.     

Conversion factor for comparison of data from Humphrey and Medmont automated perimeters

Background : Clinical experience has shown that the sensitivity indices reported by the Humphrey Field Analyser (HFA) are generally higher than those given by the Medmont Automated Perimeter (M600). It is the purpose of this paper to determine a conversion factor for the two perimeters and to confirm this prediction using clinical data. Theory predicted that HFA_sensitivity ? 5 dB = M600_sensitivity. Methods : Sensitivity versus eccentricity profiles were measured over the central visual field on 10 young subjects using both perimeters. Results : Both the HFA and the M600 operate within the realms of the Weber law and measure similar Weber fractions. The sensitivity profiles had similar slopes (about ?0.2 dB/degree) and were separated by about six decibels with the HFA reporting higher sensitivity values. This result confirmed the theoretical prediction. Conclusion : The difference in threshold sensitivities between the two perimeters is a result of differences in scaling factors and instrument luminances. A suggested clinical conversion factor is to subtract 5 dB from the HFA data to approximate those of the M600.     

Abdominal angiostrongyliasis in Nicaragua: a clinico-pathological study on a series of 12 cases reports.

A retrospective study was done to determine the presence of abdominal angiostrongyliasis in Nicaragua. Twelve cases of this parasitic disease were found among 48 visceral specimens: small intestine, liver and testes. The patients with intestinal lesions presented symptoms of an acute abdomen, and in some instances, a tumor-like mass was palpated in the lower right quadrant. A thickening of the intestinal wall accompanied by necrosis and perforation were the most important macroscopic findings. One patient with hepatic localisation of Angiostrongylus costaricencis displayed a clinical picture of visceral larva migrans-like syndrome. The chief laboratory findings were leukocytosis and eosinophilia. The histopathological examination showed granulomas and heavy eosinophilic infiltration around the eggs and larvae of A. costaricencis. Also, an adult worm was seen in one biopsy.