CYP46A1-mediated cholesterol turnover induces sex-specific changes in cognition and counteracts memory loss in ovariectomized mice

The brain-specific enzyme CYP46A1 controls cholesterol turnover by converting cholesterol into 24S-hydroxycholesterol (24OH). Dysregulation of brain cholesterol turnover and reduced CYP46A1 levels are observed in Alzheimer's disease (AD). In this study, we report that CYP46A1 overexpression in aged female mice leads to enhanced estrogen signaling in the hippocampus and improved cognitive functions. In contrast, age-matched CYP46A1 overexpressing males show anxiety-like behavior, worsened memory, and elevated levels of 5α-dihydrotestosterone in the hippocampus. We report that, in neurons, 24OH contributes to these divergent effects by activating sex hormone signaling, including estrogen receptors. CYP46A1 overexpression in female mice protects from memory impairments induced by ovariectomy while having no effects in gonadectomized males. Last, we measured cerebrospinal fluid levels of 24OH in a clinical cohort of patients with AD and found that 24OH negatively correlates with neurodegeneration markers only in women. We suggest that CYP46A1 activation is a valuable pharmacological target for enhancing estrogen signaling in women at risk of developing neurodegenerative diseases.

Fluoxetine Affects Differentiation of Midbrain Dopaminergic Neurons In Vitro

Recent meta-analyses found an association between prenatal exposure to the antidepressant fluoxetine (FLX) and an increased risk of autism in children. This developmental disorder has been related to dysfunctions in the brains' rewards circuitry, which, in turn, has been linked to dysfunctions in dopaminergic (DA) signaling. The present study investigated if FLX affects processes involved in dopaminergic neuronal differentiation. Mouse neuronal precursors were differentiated into midbrain dopaminergic precursor cells (mDPCs) and concomitantly exposed to clinically relevant doses of FLX. Subsequently, dopaminergic precursors were evaluated for expression of differentiation and stemness markers using quantitative polymerase chain reaction. FLX treatment led to increases in early regional specification markers orthodenticle homeobox 2 (Otx2) and homeobox engrailed-1 and -2 (En1 and En2). On the other hand, two transcription factors essential for midbrain dopaminergic (mDA) neurogenesis, LIM homeobox transcription factor 1 α (Lmx1a) and paired-like homeodomain transcription factor 3 (Pitx3) were downregulated by FLX treatment. The stemness marker nestin (Nes) was increased, whereas the neuronal differentiation marker β3-tubulin (Tubb3) decreased. Additionally, we observed that FLX modulates the expression of several genes associated with autism spectrum disorder and downregulates the estrogen receptors (ERs) α and β Further investigations using ERβ knockout (BERKO) mDPCs showed that FLX had no or even opposite effects on several of the genes analyzed. These findings suggest that FLX affects differentiation of the dopaminergic system by increasing production of dopaminergic precursors, yet decreasing their maturation, partly via interference with the estrogen system.

Comparison of surgical treatment and nonoperative management for radial longitudinal deficiency

We compared the radiological and functional outcomes in patients with radial longitudinal deficiency treated surgically with those managed nonoperatively and correlated the ease of performance of activities with radiological and functional parameters in the two groups. A retrospective analysis was done in 446 type 3 and 4 hands (modified Bayne classification) over 20 years comparing the subjective assessment, objective and functional scores in nonoperatively managed hands (Group 1; n = 137) to hands managed with centralization or radialization (Group 2; n = 309). The subjective, objective and functional measures were significantly better in Group 2. Improved alignment, finger and wrist range of motion and grip strength were related to improvement in functional score. Surgical treatment of radial longitudinal deficiency provides improvement in cosmesis, function and ease of performance of activities when compared with nonoperatively managed hands.

Computed tomography-guided radiofrequency ablation of osteoid osteomas

PURPOSE

To report on 14 patients with osteoid osteomas treated by computed tomography-guided radiofrequency ablation.

METHODS

Nine males and 5 females aged 13 to 45 (mean, 25) years with osteoid osteomas were included. The proximal tibia was the commonest site involved. A bipolar 18-gauge radiofrequency probe with a 9- mm active tip was used. A 4.5-mm hollow drill was introduced into the nidus. Energy application was started at 2 W and increased to a maximum of 5 W. Heat was applied for 4 to 6 minutes at 90 degrees Celsius.

RESULTS

12 (86%) of the 14 patients had prompt pain relief; the remaining 2 underwent a repeat ablation. After a mean follow-up period of 19 (range, 9-25) months, no patient had pain recurrence.

CONCLUSION

Radiofrequency ablation is a minimally invasive and cost-effective treatment for osteoid osteomas.

Dextrose prolotherapy for recalcitrant coccygodynia

PURPOSE

To present the results of dextrose prolotherapy undertaken for chronic non-responding coccygodynia in 37 patients.

METHODS

14 men and 23 women (mean age, 36 years) with chronic coccygodynia not responding to conservative treatment for more than 6 months were included. 27 of them had received local steroid injections. A visual analogue score (VAS) was recorded for all patients before and after injection of 8 ml of 25% dextrose and 2 ml of 2% lignocaine into the coccyx. In 8 patients with a VAS of more than 4 after the second injection, a third injection was given 4 weeks later.

RESULTS

The mean VAS before prolotherapy was 8.5. It was 3.4 after the first injection and 2.5 after the second injection. Minimal or no improvement was noted in 7 patients; the remaining 30 patients had good pain relief.

CONCLUSION

Dextrose prolotherapy is an effective treatment option in patients with chronic, recalcitrant coccygodynia and should be used before undergoing coccygectomy. Randomised studies are needed to compare prolotherapy with local steroid injections or coccygectomies.

Tuberculosis of the sternum

A series of 14 patients suffering from tuberculosis of the sternum with a mean follow-up of 2.8 years (2 to 3.6) is presented. All were treated with antitubercular therapy: ten with primary therapy, two needed second-line therapy, and two required surgery (debridement). All showed complete healing and no evidence of recurrence at the last follow-up. MRI was useful in making the diagnosis at an early stage because atypical presentations resulting from HIV have become more common. Early adequate treatment with multidrug antitubercular therapy avoided the need for surgery in 12 of our 14 patients.

Treatment of aneurysmal bone cysts with percutaneous sclerotherapy using polidocanol. A review of 72 cases with long-term follow-up

Aneurysmal bone cyst is a rare tumour-like lesion which develops during growth. Our aim was to determine the efficacy of the administration of percutaneous intralesional 3% polidocanol (hydroxypolyaethoxydodecan) as sclerotherapy. Between July 1997 and December 2004 we treated 72 patients (46 males, 26 females) with a histologically-proven diagnosis of aneurysmal bone cyst, at various skeletal sites using this method. The sclerotherapy was performed under fluoroscopic guidance and general anaesthesia or sedation and local anaesthesia. The mean follow-up period was 34 months (26.5 to 80). The patients were evaluated using the Enneking system for functional assessment and all the lesions were radiologically quantified into four grades. The mean age of patients was 15.6 years (3 to 38) and the mean number of injections was three (1 to 5). Ten patients were cured by a single injection. The mean reduction in size of the lesion (radiological healing) was found to be 76.6% (61.9% to 93.2%) with a mean clinical response of 84.5% (73.4% to 100%). Recurrence was seen in two patients (2.8%) within two years of treatment and both were treated successfully by further sclerotherapy. Percutaneous sclerotherapy with polidocanol is a safe alternative to conventional surgery for the treatment of an aneurysmal bone cyst. It can be used at surgically-inaccessible sites and treatment can be performed on an out-patient basis.

Isolated tuberculosis of the coccyx

Vertebral disease constitutes approximately 50% of all skeletal tuberculosis. We describe a patient who developed a discharging sinus at the tip of the coccyx. Extensive examination revealed isolated tuberculosis of the coccyx. Although rare, the condition should be suspected in patients presenting with a chronic sinus in the sacrococcygeal area and a lytic lesion in the coccyx on CT or MRI, particularly in the developing world.

Effect of simultaneous isoniazid administration on pharmacokinetic parameters of pyrazinamide

Pyrazinamide (PZN) was administered to 10 patients of pulmonary tuberculosis (for 7 consecutive days) each day after an overnight fast. On 8th day serum levels and urinary elimination were measured at 2,4,6 and 8 hours. Simultaneous administration of isoniazid to same patients significantly decreased the peak serum concentration (Cmax). Although, time to peak serum concentration (Tmax) remained unaffected, serum half life (t1/2) prolonged, the elimination rate constant (Kel) and area under serum concentration time curve (AUC) decreased and apparent volume of distribution (Vd) and plasma clearance (Clp) of PZN increased significantly. However, the cumulative per cent dose of PZN excreted in urine was not changed significantly. Although, serum levels of PZN were decreased at 2, 4, 6, and 8 hours, PZN levels remained above minimum effective concentration thereby not affecting the therapeutic status of PZN administered in combination with isoniazid, if PZN is administered in moderate doses.