Influence of cholinergic circuitries in generation of high-frequency somatosensory evoked potentials.

OBJECTIVE: High-frequency oscillations (HFOs) evoked by upper limb stimulation reflect highly synchronised spikes generated in the somatosensory human system. Since acetylcholine produces differential modulation in subgroups of neurons, we would determine whether cholinergic drive influences HFOs. METHODS: We recorded somatosensory evoked potentials (SEPs) from 31 scalp electrodes in 7 healthy volunteers, before and after single administration of rivastigmine, an inhibitor of central acetylcholinesterase. Right median nerve SEPs have been analysed after digital narrow bandpass filtering (500-700 Hz). Raw data were further submitted to Brain Electrical Source analysis (BESA) to evaluate the respective contribution of lemniscal, thalamic and cortical sources. Lastly, we analysed by Fast Fourier transform spectral changes after drug administration in the 10-30 ms latency range. RESULTS: Rivastigmine administration caused a significant increase of HFOs in the 18-28 ms latency range. Wavelets occurring before the onset latency of the conventional N20 SEP did not show any significant change. A similar increase concerned the strength of cortical dipolar sources in our BESA model. Lastly, we found a significant power increase of the frequency peak at about 600 Hz in P3-F3 traces after drug intake. CONCLUSIONS: Our findings demonstrate that the cortical component of HFOs is significantly enhanced by cholinergic activation. Pyramidal chattering cells, which are capable to discharge high-frequency bursts, are mainly modulated by cholinergic inputs; by contrast, acetylcholine does not modify the firing rate of fast-spiking GABAergic interneurons. We thus discuss the hypothesis that cortical HFOs are mainly generated by specialised pyramidal cells.     

The journey from the old to the new AMH assay: how to avoid getting lost in the values

Anti-Müllerian hormone (AMH) is set to dominate reproductive endocrinology because of its unique relationship with the ovarian reserve. To date half of the published articles have used the Diagnostic Systems Lab (DSL) assay and the other half the Immunotech (IOT) assay. Unfortunately, these assays utilize two different primary antibodies against AMH and different standards, and consequently the crude values reported can differ substantially, with the IOT assay giving values for AMH that are higher than those obtained with the DSL assay. With the recent consolidation of these two companies by Beckman Coulter, and their sole ownership of the patent to measure mammalian AMH, there is finally a single commercially available assay - the AMH Gen II assay, which will fully replace the DSL and IOT assays. The aim of this article is to briefly focus on the different assays for AMH evaluation in order to give readers hopefully helpful suggestions for a correct interpretation of the AMH measurement. A brief overview on the development and performance characteristics of the new assay, how it relates to previous values and previously developed nomograms and where the future lies for AMH is also provided.     

Comparison of biochemical markers of bone turnover and bone mineral density in different groups of climacteric women.

In the present study we evaluated plasma levels of two markers of bone turnover (osteocalcin (OC) and urinary pyridinium cross-links) in association with bone mineral density (BMI) in different groups of climacteric women. We have investigated 158 women in pre-, peri- and postmenopause. Blood and urine samples for assay of hormones and markers were collected and bone mineral density (BMD) was measured by DEXA densitometry in the distal tenth of the non-dominant forearm. There was a significant increase in mean absolute levels of both markers in perimenopause and women in natural and surgical menopause, with respect to women in premenopause. There was a significant correlation between OC and deoxypyridoline (DPYR) in peri- and postmenopause groups. In peri- and postmenopause groups, BMD was correlated with an increase in the biochemical markers of bone remodeling. In the present study, OC and DPYR were found to have good sensitivity for identifying perimenopausal women with pathological BMD. The present results reveal a positive and significant correlation between DPYR and OC, inversely proportional to BMD, during hormone replacement therapy. These markers therefore turn out to be sensitive not only for monitoring severe pathology of bone turnover, but also for monitoring slight physiological deficits in bone equilibrium beginning in perimenopause.     

Low-dose danazol after combined surgical and medical therapy reduces the incidence of pelvic pain in women with moderate and severe endometriosis.

The most effective therapy for endometriosis is a matter for debate. The aim of the present randomized study was to evaluate the efficacy of low doses of danazol on recurrence of pelvic pain in patients with moderate or severe endometriosis, who had undergone laparoscopic surgery and 6 months of gonadotrophin-releasing hormone analogue (GnRHa) therapy. After surgery, 28 patients with moderate or severe endometriosis underwent therapy for 6 months with GnRHa i. m. every 4 weeks. They were then randomized into two groups: group A (14 subjects) was treated with 100 mg/day danazol for 6 months; group B (14 subjects, control) did not receive any type of therapy. After 12 months of treatment, group A had a significantly (P < 0.01) lower pain score than group B. There was no significant difference between the groups in oestrogen concentrations, bone mineral density or side-effects. The results suggest that low-dose danazol therapy reduces recurrence of pelvic pain in patients with moderate or severe endometriosis, treated surgically, and has few or no metabolic side-effects.     

The Anti-Mullerian hormone and ovarian cancer

The Anti-Mullerian hormone (AMH), which is produced by fetal Sertoli cells, is responsible for regression of Mullerian ducts, the anlagen for uterus and Fallopian tubes, during male sex differentiation. Ovarian granulosa cells also secrete AMH from late in fetal life. The patterns of expression of AMH and its type II receptor in the post-natal ovary indicate that AMH may play an important role in ovarian folliculogenesis. Recent advances in the physiological role of AMH has stimulated interest in the significance of AMH as a diagnostic marker and therapeutic agent for ovarian cancer. Currently, AMH has been shown to be a circulating marker specifically for granulosa cell tumour (GCT). Its diagnostic performance seems to be very good, with a sensitivity ranging between 76 and 93%. In patients treated for GCT, AMH may be used post-operatively as marker for the efficacy of surgery and for disease recurrence. Based on the physiological inhibitory role of AMH in the Mullerian ducts, it has been proposed that AMH may inhibit epithelial ovarian cancer cell both in vitro and in vivo. These observations will be the basis for future research aiming to investigate the possible clinical role of AMH as neo-adjuvant, or most probably adjuvant, therapy for ovarian cancer.     

Research from the Model Spinal Cord Injury Systems: findings from the current 5-year grant cycle

This issue of the Archives of Physical Medicine and Rehabilitation is dedicated to current research findings of the Model Spinal Cord Injury Systems (MSCIS) program. The MSCIS grants were established by the Rehabilitation Services Administration in the 1970s. Now administered by the National Institute on Disability and Rehabilitation Research within the Office of Special Education and Rehabilitation Services in the US Department of Education, the program has included 27 spinal cord injury centers in the United States over the years. In the current 5-year grant cycle (2000-2005), there are 16 designated regional MSCIS centers. In addition to establishing a comprehensive system of care, the grantees contribute patient data to the National Spinal Cord Injury Database (which now contains data on 30,532 subjects with follow-up of up to 30 y). In addition, the MSCIS grants enable the conduct of site-specific and collaborative research projects. To highlight the research findings of the program, the MSCIS have produced a special dissemination effort during each of the previous 5 grant cycles, with this issue of the Archives representing the latest of these endeavors. This article provides a brief history of the MSCIS program and highlights the important findings of the 17 original research articles contained in this issue.     

Live birth rates in the different combinations of the Bologna criteria poor ovarian responders: a validation study

Purpose

to compare the baseline characteristics and chance of live birth in the different categories of poor responders identified by the combinations of the Bologna criteria and establish whether these groups comprise a homogenous population.

Methods

database containing clinical and laboratory information on IVF treatment cycles carried out at the Mother-Infant Department of the University Hospital of Modena between year 2007 and 2011 was analysed. This data was collected prospectively and recorded in the registered database of the fertility centre. Eight hundred and thirty women fulfilled the inclusion/ exclusion criteria of the study and 210 women fulfilled the Bologna criteria definition for poor ovarian response (POR). Five categories of poor responders were identified by different combinations of the Bologna criteria.

Results

There were no significant differences in female age, AFC, AMH, cycle cancellation rate and number of retrieved oocytes between the five groups. The live birth rate ranged between 5.5 and 7.4 % and was not statistically different in the five different categories of women defined as poor responders according to the Bologna criteria.

Conclusion

The study demonstrates that the different groups of poor responders based on the Bologna criteria have similar IVF outcomes. This information validates the Bologna criteria definition as women having a uniform poor prognosis and also demonstrates that the Bologna criteria poor responders in the various subgroups represent a homogenous population with similar pre-clinical and clinical outcomes.     

A Chaperone Enhances Blood α-Glucosidase Activity in Pompe Disease Patients Treated With Enzyme Replacement Therapy

Enzyme replacement therapy is currently the only approved treatment for Pompe disease, due to acid α-glucosidase deficiency. Clinical efficacy of this approach is variable, and more effective therapies are needed. We showed in preclinical studies that chaperones stabilize the recombinant enzyme used for enzyme replacement therapy. Here, we evaluated the effects of a combination of enzyme therapy and a chaperone on α-glucosidase activity in Pompe disease patients. α-Glucosidase activity was analyzed by tandem-mass spectrometry in dried blood spots from patients treated with enzyme replacement therapy, either alone or in combination with the chaperone N-butyldeoxynojirimycin given at the time of the enzyme infusion. Thirteen patients with different presentations (3 infantile-onset, 10 late-onset) were enrolled. In 11 patients, the combination treatment resulted in α-glucosidase activities greater than 1.85-fold the activities with enzyme replacement therapy alone. In the whole patient population, α-glucosidase activity was significantly increased at 12 hours (2.19-fold, P = 0.002), 24 hours (6.07-fold, P = 0.001), and 36 hours (3.95-fold, P = 0.003). The areas under the curve were also significantly increased (6.78-fold, P = 0.002). These results suggest improved stability of recombinant α-glucosidase in blood in the presence of the chaperone.