Rupture of De Novo Middle Cerebral Artery Aneurysm 8 Years After the Clipping of Ruptured M1 Middle Cerebral Artery Aneurysm.

BACKGROUND Development and rupture of a de novo intracranial aneurysm is rare. Little is known regarding its etiology and the appropriate timing of follow-up angiograms after surgical clipping or coiling. CASE REPORT We present a case report of a 39-year-old male smoker with history of hypertension who developed a de novo aneurysm 8 years after surgical clipping of an aneurysm in the middle cerebral artery in the same segment. He presented with neck rigidity and drowsiness. Laboratory analysis did not show blood dyscrasia. Brain computerized tomography showed right temporal lobe hematoma and 4-vessel angiogram demonstrated de novo aneurysm in the same segment of the M1 middle cerebral artery, which was confirmed by intraoperative microsurgical findings. We review the literature on such cases and discuss the pathophysiology, diagnosis, and treatment of this condition. De novo aneurysm, although rare, can develop within days to as long as 10 years after surgical clipping or coiling. CONCLUSIONS This rare case of de novo aneurysm supports follow-up imaging of patients after initial surgical clipping for up to 10 years.

Microsurgical Fenestration of Intracranial Arachnoid Cysts: Volumetric Analysis and Clinical Outcome.

INTRODUCTION: There is paucity of data regarding change in arachnoid cyst (AC) volume following surgery. This study aimed at investigating the clinical outcome of ACs and applying 2 volumetric methods for determination of their volume change post microsurgical fenestration. METHODS: Twenty-one ACs in 20 patients that underwent microsurgical fenestration were analyzed using 2 volumetric methods; the modified McDonald equation and the picture archiving and communication (PAC) system-based method. Patients were followed up for 23 ± 40.3 months. RESULTS: The majority of the patients (13 or 65%) were children. Preoperative symptoms in children were mainly seizures and less commonly headache. Of the 20 patients, 12 (60%) had complete resolution of their preoperative symptoms with 8 (40.0%) showing partial improvement. Volumetric studies showed a mean reduction in AC size of 73.7% in children and 64.4% in adults using the PAC system versus 67.9% in children and 70.5% in adults using the modified McDonald equation method. There was no correlation between the percentage decrease in AC volume post surgery and degree of symptom improvement (49.2 ± 34.3% in patients with complete vs. 60.9 ± 40.3% in patients with only partial resolution of symptoms, p = 0.57). DISCUSSION/CONCLUSION: Microsurgical fenestration is an effective approach for ACs with an excellent clinical outcome apparent in the complete or partial improvement of symptoms in all patients. Volumetric estimates of ACs and their change following surgery are feasible using the modified McDonald or PAC system methods. However, there is no correlation between the percentage decrease in AC volume after surgery and degree of clinical improvement.

Tuning electrical and thermal conductivities of the two-dimensional electron gas in AlN/GaN heterostructures by piezoelectricity.

We investigate the electrical and thermal conductivities of the two-dimensional electron gas (2DEG) confined in the quantum well formed at the heterojunction between a thin GaN layer and an AlN layer strained by an Al x Ga1-x N capping layer in the temperature range from 10 to 360 K. The experimental protocol developed to deduce from calorimetric and Hall-effect measurements at a variable temperature the critical characteristics and transport properties of the confined 2DEG is presented. It is found that, in the measured temperature range (10-360 K), the electrical conductivity of the 2DEG is temperature-independent, due to the predominance of scattering processes by interface defects. However, the thermal conductivity shows a linear temperature dependence, mirroring the specific heat of free electrons. The temperature-independent relaxation time associated with the overall electron scattering means that the values obtained for electrical and thermal conductivities are in excellent agreement with those stipulated by the Weidemann-Franz law. It is also found that for weak strain fields in the AlN layer, both the electrical and thermal conductivities of the two-dimensional interfacial electrons increase exponentially with strain. The importance of 2DEG in AlN/GaN quantum wells lies in the fact that the strong piezoelectricity of AlN allows the transport properties of the 2DEG to be tuned or modulated by a weak electric field even with the high density of lattice mismatch induced defects at the AlN-GaN interface .

Systems toxicology meta-analysis of in vitro assessment studies: biological impact of a candidate modified-risk tobacco product aerosol compared with cigarette smoke on human organotypic cultures of the aerodigestive tract.

Systems biology combines comprehensive molecular analyses with quantitative modeling to understand the characteristics of a biological system as a whole. Leveraging a similar approach, systems toxicology aims to decipher complex biological responses following exposures. This work reports a systems toxicology meta-analysis in the context of in vitro assessment of a candidate modified-risk tobacco product (MRTP) using three human organotypic cultures of the aerodigestive tract (buccal, bronchial, and nasal epithelia). Complementing a series of functional measures, a causal network enrichment analysis of transcriptomic data was used to compare quantitatively the biological impact of aerosol from the Tobacco Heating System (THS) 2.2, a candidate MRTP, with 3R4F cigarette smoke (CS) at similar nicotine concentrations. Lower toxicity was observed in all cultures following exposure to THS2.2 aerosol compared with 3R4F CS. Because of their morphological differences, a smaller exposure impact was observed in the buccal (stratified epithelium) compared with the bronchial and nasal (pseudostratified epithelium). However, the causal network enrichment approach supported a similar mechanistic impact of CS across the three cultures, including the impact on xenobiotic, oxidative stress, and inflammatory responses. At comparable nicotine concentrations, THS2.2 aerosol elicited reduced and more transient effects on these processes. To demonstrate the benefits of additional data modalities, we employed a newly established targeted mass-spectrometry marker panel to further confirm the reduced cellular stress responses elicited by THS2.2 aerosol compared with 3R4F CS in the nasal culture. Overall, this work demonstrates the applicability and robustness of the systems toxicology approach for in vitro inhalation toxicity assessment.

Endovascular treatment of very small intracranial aneurysms.

The endovascular treatment of intracranial aneurysms 3 mm or less is considered controversial. The purpose of this study is to report angiographic and clinical results following coiling of such aneurysms and compare them to those of larger aneurysms (> 3 mm).Between November 1999 and November 2009 endovascular treatment was attempted in 956 consecutive intracranial aneurysms. Of 956 aneurysms, 111 aneurysms were very small aneurysms with a maximal diameter of 3 mm or less. We conducted a retrospective analysis of angiographic and clinical outcome following coiling of very small aneurysms and subsequently comparing it to the results of larger aneurysms.Coiling initially failed in eight aneurysms. In the remaining 103 aneurysms endovascular treatment was accomplished and immediate angiographic results showed complete aneurysm occlusion in 43 aneurysms, nearly complete aneurysm occlusion in 54 aneurysms and less than 90% aneurysm occlusion in six aneurysms. Complications occurred in the treatment of 15 aneurysms, including eight procedural ruptures, six thromboembolic events and one case of early hemorrhage. Compared with larger aneurysms, treatment of very small aneurysms was associated with a higher rate of procedural ruptures (7.2% versus 4.4%) and procedural mortality (4.7% versus 2.7%) but a lower procedural morbidity (1.9% versus 4.0%). However none of these differences reached statistical significance (p = 0.186, p= 0.388, respectively). The retreatment rate was higher for the larger aneurysms (8.2% and 6.3%), but this was not significant either (p= 0. 496). At nine-month follow-up significantly more small aneurysms were found to have a stable occlusion grade compared to large aneurysms.Endovascular treatment of very small aneurysms is feasible with a lower retreatment rate compared to large aneurysms (> 3 mm). However the data also suggest that endovascular treatment of very small aneurysms might be associated with an increased risk of procedural ruptures and mortality. At nine-month follow-up results indicate significantly less compaction in the very small aneurysms.

An Epidemiological Study of Abdominal and Pelvic Injury Trauma in post-mortem Cases at Hospital Kuala Lumpur Between The Year of 2002-2003 / Jurnal Sains Kesihatan Malaysia

The abdominal pelvic cavity has always been regarded as one of the most vulnerable regions of the body. Injuries to this part have been known to be very serious. Based on this a retrospective study was performed on postmortem cases with abdominal and pelvic trauma from 1 October 2002 to 31 January 2003 at the Forensic Institute, Hospital Kuala Lumpur to determine the common pattern of abdomino-pelvic injuries, the injury’s relationship to epidemiological and socio-economic factors, risk organ within the abdominopelvic region and relationship between injuries and survival period. A total of 122 cases abdomino-pelvic were obtained stemming from medico legal postmortems procedures. Results indicated that those aged between 21 to 30 years (38.5%) had the highest incidence of this type of injury. Categorization based on gender showed that males (90.2%) dominated most of the cases. Prevalence based on socio-economic status showed that lower socioeconomy class (52.5%) had the highest incident. This was followed by the middle income (39.3%) and finally the higher income group. The most numerous type of trauma was non-penetrating trauma (94.3%). It was also found that victims with low injury severity score (ISS) had a longer survival period as compared to those with high ISS. It was also noted that victims with two or more region injuries either were spot dead or brought dead. The most common combination of injuries was abdomen, pelvic, chest and limb. In most blunt trauma cases majority of victims had one or two organ involvement while penetrating injuries were difficult to asses. The most common organ involved in this type of trauma was liver (72.1%), pelvic bone (47.5%) and spleen (43.4%). In conclusion, abdomino-pelvic injury is a serious condition and should not be overlooked. Proper attention towards their diagnosis and management is important and so any patient of head injury with coma must be considered as having intra-abdominal injury until proven otherwise.

Rational solitons in deep nonlinear optical Bragg grating.

We have examined the rational solitons in the Generalized Coupled Mode model for a deep nonlinear Bragg grating. These solitons are the degenerate forms of the ordinary solitons and appear at the transition lines in the parameter plane. A simple formulation is presented for the investigation of the bifurcations induced by detuning the carrier wave frequency. The analysis yields among others the appearance of in-gap dark and antidark rational solitons unknown in the nonlinear shallow grating. The exact expressions for the corresponding rational solitons are also derived in the process, which are characterized by rational algebraic functions. It is further demonstrated that certain effects in the soliton energy variations are to be expected when the frequency is varied across the values where the rational solitons appear.