Is the failure to detect stimulus deviance during sleep due to a rapid fading of sensory memory or a degradation of stimulus encoding?

The mismatch negativity (MMN) is thought to reflect the outcome of a system responsible for the detection of change in an otherwise repetitive, homogenous acoustic environment. This process depends on the storage and maintenance of a sensory representation of the frequently presented stimulus to which the deviant stimulus is compared. Few studies have been able to record the MMN in non-rapid eye movement (NREM) sleep. This pattern of results might be explained by either a rapid fading of sensory memory or an inhibition of stimulus input prior to entry into the cortical MMN generator site. The present study used a very rapid rate of presentation in an attempt to capture mismatch-related negativity prior to the fading of sensory memory. Auditory event-related potentials were recorded from 12 subjects during a single sleep period. A 1000 Hz standard stimulus was presented every 150 ms. At random, on 6.6% of the trials, the standard was changed to either a large 2000 Hz or a small 1100 Hz deviant. In wakefulness, the large deviant elicited an extended negativity that was reduced in amplitude following the presentation of the small deviant. This negativity was also apparent during REM sleep following the presentation of the large deviant. These deviant-related negativities (DRNs) were probably a composite of N1 and MMN activity. During NREM sleep (stage 2 and slow-wave sleep), only the large deviant continued to elicit a DRN. However this DRN might be overlapped by the initial activity of a component that is unique to sleep, the N350. There was little evidence of the DRN or the MMN during sleep following the presentation of the small deviant. A rapid rate of presentation, therefore, does not preserve the MMN following small deviance within sleep. It is possible that inhibition of sensory input occurs before entry into the MMN generating system in the temporal cortex.     

Loss of long-term potentiation in the hippocampus after experimental subarachnoid hemorrhage in rats

Survivors of aneurysmal subarachnoid hemorrhage (SAH) often suffer from cognitive impairment such as memory loss. However, the underlying mechanisms of these impairments are not known. Long-term potentiation (LTP) of synapses in the hippocampus is generally regarded as a molecular substrate of memory. The purpose of this study was to examine the effect of SAH on LTP in the hippocampal Schaffer collateral (CA3–CA1) pathway in a rat model of SAH. We found SAH caused significant vasospasm of the middle cerebral artery (MCA) compared to saline injected or sham controls (P<0.001). Basic neurotransmission quantified as excitatory post synaptic and spike response from animals with SAH were significantly decreased as compared to naive controls (P<0.05). However, sham operated and saline injected controls showed similar amplitude as naive controls. This suggests that reduction in basic neurotransmission is due to blood in the subarachnoid space. Similarly, analysis of LTP demonstrated that naive, sham and saline controls have a 92±16%, 69±27% and 71±14% increase over the baseline in the average spike amplitude following high frequency stimulation (HFS), respectively. This indicates the presence of LTP (P<0.05). In contrast, the spike amplitude in animals of SAH returned to baseline level within 60 min post HFS indicating the absence of LTP. We conclude that SAH caused vasospasm of the MCA that was associated with disrupted basic neurotransmission and plasticity at CA3–CA1 synapses. These changes might be accountable for the memory loss in humans with SAH.     

Hepatitis E virus coinfection with hepatotropic viruses in Egyptian children

BACKGROUND AND PURPOSE: Major hepatotropic viruses continue to be important causes of acute viral hepatitis in developing countries. This work was carried out to detect the seroprevalence of hepatitis E virus (HEV) markers in children with acute viral hepatitis due to hepatotropic viruses (A, B and C) and non-A, non-B, non-C acute hepatitis, and to ascertain the influence of HEV superinfection in individuals infected with hepatitis viruses (A, B and C). METHODS: We studied prospectively 162 children with sporadic acute hepatitis who reported to our hospital. Thirteen healthy controls were also included in the study. Laboratory investigations were performed, including complete liver function tests. Complete serological profiles for hepatitis viruses A, B, C and E were evaluated. RESULTS: HEV immunoglobulin G was detected with highest percentage among patients with hepatitis B (56.7%), followed by patients with hepatitis C virus (52.0%), hepatitis A virus (34.1%) and combined hepatitis B and C viruses (30.0%). The detection rate among patients with non-A, non-B, non-C hepatitis was 7.1%. HEV immunoglobulin M was found in 4.5% of hepatitis A virus patients and in 3.3% of hepatitis B patients. The prevalence of HEV immunoglobulin G and immunoglobulin M correlated with the levels of hepatic aspartate aminotransferase and alanine aminotransferase in patients with dual markers of infection with hepatitis E and other viruses compared to patients with acute hepatitis due to A and C viruses. CONCLUSIONS: HEV serological markers are common among children with acute viral hepatitis, especially from hepatitis C and B viruses. There may be increased sensitivity to HEV coinfection in association with hepatitis B and C infections. Dual infection with HEV and other hepatotropic viruses was associated with greater elevation of aspartate and alanine aminotransferases.     

Age-related dysfunction of the lacrimal gland and oxidative stress: evidence from the Cu,Zn-superoxide dismutase-1 (Sod1) knockout mice

An imbalance between free radical generation and radical scavenging antioxidant systems results in oxidative stress, which has been associated with cell injury observed in many age-related diseases. The superoxide dismutase (SOD) family is a major antioxidant system, and deficiency of Cu,Zn-superoxide dismutase-1 (Sod1) in mice leads to many different phenotypes that resemble accelerated aging. In this study we examined the morphologic features and the secretory functions of the lacrimal glands in Sod1(-/-) mice. Lacrimal glands showed atrophy of acinar units; fibrosis; infiltration with CD4(+) T cells, monocytes, and neutrophils; increased staining with both 4-hydroxy-2-nonenal and 8-hydroxy-2'-deoxyguanosine; increases in apoptotic cells; and the presence of the epithelial-mesenchymal transition in senescent Sod1(-/-) mice. Electron microscopy findings revealed evidence of epithelial-mesenchymal transition, presence of swollen and degenerated mitochondria, and the presence of apoptotic cell death in the lacrimal glands of senescent Sod1(-/-) mice. These alterations were also associated with the accumulation of secretory vesicles in acinar epithelial cells, decreased production of both stimulated and nonstimulated tears, and a decline in total protein secretion from the lacrimal glands. Our results suggest that Sod1(-/-) mice may be a good model system in which to study the mechanism of reactive oxygen species-mediated lacrimal gland alterations.     

Psychometric Properties of an Arabic Pain Anxiety Symptoms Scale-20 (PASS-20) in Healthy Volunteers and Patients Attending a Physiotherapy Clinic

Purpose

The aim of this study was to cross-culturally adapt the PASS-20 questionnaire for use in Libya.

Methods

Participants were 71 patients (42 women) attending the physiotherapy clinic, Ibn Sina Hospital, Sirt, Libya for management of persistent pain and 137 healthy unpaid undergraduate students (52 women) from the University of Sirt, Libya. The English PASS-20 was translated into Arabic. Patients completed the Arabic PASS-20 and the Arabic Pain Rating Scales on two occasions separated by a 14-day interval. Healthy participants completed the Arabic PASS-20 on one occasion.

Results

The internal consistency (ICC) for pain patient and healthy participant samples yielded a good reliability for the total score, cognitive anxiety, fear of pain, and physiological anxiety. The test-retest reliability of the Arabic PASS-20 score showed high reliability for the total score (ICC = 0.93, p < 0.001), escape/avoidance (ICC = 0.93, p < 0.001), fear of pain (ICC = 0.94, p < 0.001), and physiological anxiety subscales (ICC = 0.96, p < 0.001) and good reliability for the cognitive anxiety (ICC = 0.85, p < 0.001). Inspection of the Promax rotation showed that each factor comprised of five items were consistent with the theoretical constructs of the original PASS-20 subscales.

Conclusion

The Arabic PASS-20 retained internal consistency and reliability with the original English version and can be used to measure pain anxiety symptoms in both pain and healthy individual samples in Libya.

     

High Grade Gynecomastia: Surgical Correction and Potential Impact on Erectile Function

IntroductionGynecomastia denotes benign enlargement of the male breast. It is a common belief that gynecomastia is stigmatizing and may frequently cause social embarrassment and psychological stress. It is possible that this may reflect on erectile function of the afflicted. High grade gynecomastia requires radical breast tissue excision and skin reduction ending up in aesthetically unappealing scars.AimThe purpose of this study is to evaluate the reduction mammaplasty using no vertical scar technique in males with high grade gynecomastia; as regards technical refinements and outcome in the hope of providing a cosmetically appealing solution to this condition. This study also reports on the effect of high grade gynecomastia on erectile function, as well as the effect of surgery.MethodsFifteen male patients with gynecomastia underwent breast reduction using the “no vertical scar reduction mammaplasty.” Erectile function was evaluated before and after surgery.Main Outcome MeasuresSurgical outcome and erectile function.ResultsAll patients but one were satisfied with the outcome. Complications were minimal and manageable. Eleven out of 15 patients had a preoperative International Index of Erectile Function (IIEF) score less than 20 denoting erectile dysfunction. All but one (n = 10) showed improvement in their IIEF score following surgery. The difference between pre-operative IIEF (average 17.8) and postoperative (average 23.5) was statistically significant.ConclusionsThe “no vertical scar reduction mammaplasty” is a reliable technique in cases with gynecomastia and significant ptosis. It has the added benefits of avoiding the vertical scar, hiding the transverse scar in the shadow of the inferior aspect of the breast, with minimal complications. Gynecomastia as a condition causing a feminized outlook may have a negative impact on self confidence and body image. We suggest that this may have a potential negative effect on erectile function, that can be improved by adequate surgical correction. El Noamani S, Thabet AM, Enab AA, Shaeer O, and El-Sadat A. High grade gynecomastia: Surgical correction and potential impact on erectile function.     

Trans-corporal incision of Peyronie's plaques

IntroductionPatients presenting with Peyronie's disease (PD) curvature and erectile dysfunction (ED) can achieve straightening and rigidity through penile prosthesis implantation and manual modeling and, if necessary, a relaxing tunical incision with or without grafting. Unfortunately, this maneuver will not correct PD‐induced shortening. In addition, incision and grafting after the prosthesis has already been implanted adds to operative time and risk, and may indicate mobilization of the neurovascular bundle and, possibly, a secondary skin incision.AimThis work describes trans‐corporal incision (TCI), a minimally invasive endoscopic approach for plaque incision from within the corpora cavernosa, restoring straightness and length to the penis, before calibration of the corpora cavernosa, allowing implantation of a longer prosthesis in a straight penis, with neither mobilizing the neurovascular bundle nor a secondary incision.MethodsSixteen patients with PD deformity and refractory ED were operated upon. Intra‐operative artificial erection demonstrated the deformity. Through a penoscrotal incision, the corpora were dilated. TCI was performed to incise Peyronie's plaques at the point of maximum deformity. Artificial erection was re‐induced and correction of curvature evaluated. Length was measured before and after TCI. Implantation proceeded as usual.Main Outcome MeasuresPenile straightness and length.ResultsFollowing implantation, the penis was straight in all cases. Pre‐TCI length of the corpora was unequal on either side. Post‐TCI, both corpora were of equal length with an average increase of 2.5 cm (11.9%) on the right side and 1.9 (9.1%) on the left.ConclusionTCI; corporoscopic incision of Peyronie's plaques upon implantation of penile prosthesis is a minimally invasive approach that restores both straightness and length to patients with PD and ED, with neither mobilization of the neurovascular bundle nor plaque incision and grafting. Shaeer O. Trans‐corporal incision of Peyronie's Plaques. J Sex Med 2011;8:589–593.     

Mutations underlying 3-Hydroxy-3-Methylglutaryl CoA Lyase deficiency in the Saudi population

Background  

3-Hydroxy-3-Methylglutaric aciduria (3HMG, McKusick: 246450) is an autosomal recessive branched chain organic aciduria caused by deficiency of the enzyme 3-Hydroxy-3-Methylglutaryl CoA lyase (HL, HMGCL, EC 4.1.3.4). HL is encoded by HMGCL gene and many mutations have been reported. 3HMG is commonly observed in Saudi Arabia.