Test of the Einstein Equivalence Principle near the Galactic Center Supermassive Black Hole.

During its orbit around the four million solar mass black hole Sagittarius A* the star S2 experiences significant changes in gravitational potential. We use this change of potential to test one part of the Einstein equivalence principle: the local position invariance (LPI). We study the dependency of different atomic transitions on the gravitational potential to give an upper limit on violations of the LPI. This is done by separately measuring the redshift from hydrogen and helium absorption lines in the stellar spectrum during its closest approach to the black hole. For this measurement we use radial velocity data from 2015 to 2018 and combine it with the gravitational potential at the position of S2, which is calculated from the precisely known orbit of S2 around the black hole. This results in a limit on a violation of the LPI of |ß_{He}-ß_{H}|=(2.4±5.1)×10^{-2}. The variation in potential that we probe with this measurement is six magnitudes larger than possible for measurements on Earth, and a factor of 10 larger than in experiments using white dwarfs. We are therefore testing the LPI in a regime where it has not been tested before.

The use ultrasound guided for refilling intrathecal baclofene pump in complicated clinical cases: A practical approach.

Muscular spasticity due to neurological disorders is a heavy cause of severe pain and disability for many patients, compromising the independence and quality life. Baclofene is a good tool to guarantee patients independence and pain control. Anyway in chronic therapy oral treatment become unsatisfactory. In all these cases, intrathecal baclofen therapy (ITB), after sub fascial implantation of intrathecal pumps is used as an important long term treatment to reduce spasticity. After pump implantation the drug reservoir must be refilled periodically in order to maintain the reduction of spasticity and avoid the symptoms and signs of withdrawal. ITB refilling, which involves the insertion of a needle through the skin until the access port of the pump, is often hard, mainly due to the layer of abdominal fat, spasticity, suboptimal pump positioning, pump rotation or inversion, and scar formation over the implantation site. To avoid the difficulties of ITB refilling radiography or other invasive supportive examinations are sometimes needed. We reported here our experience and we suggest a simple method to use the ultrasound in refilling with particular attention to some cases with complications after implantation with a difficult approach in refilling. We used the ultrasound examination to identify the access port of her pump so as to avoid multiple needle punctures and infections and radiation exposition. Ultrasound-guided technique may facilitate ITB refill in technically challenging cases. With ultrasound ITB was easily detectable and was quite simple to identify the exact point of needle injection. In the last years different new applications for ultrasounds are emerging. In our opinion the use of Doppler ultrasounds in the study of muscles and nerves represent an emerging tool for the physician's neurological rehabilitation.

Strongly baryon-dominated disk galaxies at the peak of galaxy formation ten billion years ago.

In the cold dark matter cosmology, the baryonic components of galaxies-stars and gas-are thought to be mixed with and embedded in non-baryonic and non-relativistic dark matter, which dominates the total mass of the galaxy and its dark-matter halo. In the local (low-redshift) Universe, the mass of dark matter within a galactic disk increases with disk radius, becoming appreciable and then dominant in the outer, baryonic regions of the disks of star-forming galaxies. This results in rotation velocities of the visible matter within the disk that are constant or increasing with disk radius-a hallmark of the dark-matter model. Comparisons between the dynamical mass, inferred from these velocities in rotational equilibrium, and the sum of the stellar and cold-gas mass at the peak epoch of galaxy formation ten billion years ago, inferred from ancillary data, suggest high baryon fractions in the inner, star-forming regions of the disks. Although this implied baryon fraction may be larger than in the local Universe, the systematic uncertainties (owing to the chosen stellar initial-mass function and the calibration of gas masses) render such comparisons inconclusive in terms of the mass of dark matter. Here we report rotation curves (showing rotation velocity as a function of disk radius) for the outer disks of six massive star-forming galaxies, and find that the rotation velocities are not constant, but decrease with radius. We propose that this trend arises because of a combination of two main factors: first, a large fraction of the massive high-redshift galaxy population was strongly baryon-dominated, with dark matter playing a smaller part than in the local Universe; and second, the large velocity dispersion in high-redshift disks introduces a substantial pressure term that leads to a decrease in rotation velocity with increasing radius. The effect of both factors appears to increase with redshift. Qualitatively, the observations suggest that baryons in the early (high-redshift) Universe efficiently condensed at the centres of dark-matter haloes when gas fractions were high and dark matter was less concentrated.

Galaxy evolution. Evidence for mature bulges and an inside-out quenching phase 3 billion years after the Big Bang.

Most present-day galaxies with stellar masses ≥10(11) solar masses show no ongoing star formation and are dense spheroids. Ten billion years ago, similarly massive galaxies were typically forming stars at rates of hundreds solar masses per year. It is debated how star formation ceased, on which time scales, and how this "quenching" relates to the emergence of dense spheroids. We measured stellar mass and star-formation rate surface density distributions in star-forming galaxies at redshift 2.2 with ~1-kiloparsec resolution. We find that, in the most massive galaxies, star formation is quenched from the inside out, on time scales less than 1 billion years in the inner regions, up to a few billion years in the outer disks. These galaxies sustain high star-formation activity at large radii, while hosting fully grown and already quenched bulges in their cores.

High molecular gas fractions in normal massive star-forming galaxies in the young Universe.

Stars form from cold molecular interstellar gas. As this is relatively rare in the local Universe, galaxies like the Milky Way form only a few new stars per year. Typical massive galaxies in the distant Universe formed stars an order of magnitude more rapidly. Unless star formation was significantly more efficient, this difference suggests that young galaxies were much more molecular-gas rich. Molecular gas observations in the distant Universe have so far largely been restricted to very luminous, rare objects, including mergers and quasars, and accordingly we do not yet have a clear idea about the gas content of more normal (albeit massive) galaxies. Here we report the results of a survey of molecular gas in samples of typical massive-star-forming galaxies at mean redshifts of about 1.2 and 2.3, when the Universe was respectively 40% and 24% of its current age. Our measurements reveal that distant star forming galaxies were indeed gas rich, and that the star formation efficiency is not strongly dependent on cosmic epoch. The average fraction of cold gas relative to total galaxy baryonic mass at z = 2.3 and z = 1.2 is respectively about 44% and 34%, three to ten times higher than in today's massive spiral galaxies. The slow decrease between z approximately 2 and z approximately 1 probably requires a mechanism of semi-continuous replenishment of fresh gas to the young galaxies.

Occult hepatitis B virus infection in a cohort of HIV-positive patients: correlation with hepatitis C virus coinfection, virological and immunological features.

BACKGROUND: An evaluation of the prevalence of occult hepatitis B virus (HBV) infection in HIV-positive individuals is important as HBV infection may have an impact on the outcome of the liver disease in these patients. MATERIALS AND METHODS: Of the 1,593 HIV-positive subjects enrolled in the Italian Cohort Naïve Antiretroviral (ICONA) program, 175 (10.9%) were selected for inclusion in the study on the basis of hepatitis B surface antigen (HBsAg) negativity and antibody to hepatitis B core antigen (anti- HBc) positivity; 101/175 (58%) were also anti-hepatitis C virus (HCV) positive. HBV-DNA was detected in plasma using a highly sensitive PCR assay (detection limit: 2.6 copies/ml). Two different genomic regions were assayed. Quantification was performed by real-time PCR. The HBV genotype was determined in 20 cases with occult HBV infection. Data on the antiretroviral therapy (ART) regimen was obtained in 169 individuals: 53 (31.4%) patients were ART-naive, 46 (27.2%) were under ART without lamivudine or tenofovir, and the remaining 70 (41.4%) were under ART including lamivudine or tenofovir. RESULTS: 27/175 (15%) patients had detectable HBV-DNA in their plasma: 21/101 (21%) were anti-HCV positive and 6/74 (8%) were anti-HCV negative. Genotype D was invariably found in the 20 cases analyzed. Occult HBV infection was significantly higher in HCV-coinfected subjects: adjusted OR 5.02, 95% CI 1.31-19.26, p = 0.02. The value was not associated with immune status, HIV load, or ART regimen. CONCLUSIONS: In relation to the high prevalence of occult HBV infection, particularly in HIV/HCV-coinfected individuals, it is necessary to clarify the clinical impact of this cryptic infection by monitoring HBV-DNA in plasma using the correct approach. Similarly to HBsAg-positive individuals of the Mediterranean area, HBV genotype D is invariably detected in this cohort of HIV-infected patients with occult HBV infection.

Extracranial-intracranial bypass for the treatment of cavernous sinus aneurysms.

The optimal management of symptomatic cavernous sinus aneurysms remains controversial. Carotid occlusion is a simple procedure, but carries an ongoing risk of early and late stroke. Cerebral revascularisation is technically demanding and carries a risk of morbidity and mortality of around 10%. Eight patients treated with an extracranial-intracranial vascular bypass graft over a period of 44 months for symptomatic cavernous sinus aneurysms are reviewed. At a mean follow-up of 20 months, seven patients (87.5%) had an excellent outcome (Glasgow Outcome Score 5) while one patient suffered a perioperative stroke. In only one case, where the radial artery had been used, the graft became occluded. The results of this series seem to indicate that cerebral revascularisation is an effective treatment for patients with symptomatic cavernous sinus aneurysms.

The rapid formation of a large rotating disk galaxy three billion years after the Big Bang.

Observations and theoretical simulations have established a framework for galaxy formation and evolution in the young Universe. Galaxies formed as baryonic gas cooled at the centres of collapsing dark-matter haloes; mergers of haloes and galaxies then led to the hierarchical build-up of galaxy mass. It remains unclear, however, over what timescales galaxies were assembled and when and how bulges and disks--the primary components of present-day galaxies--were formed. It is also puzzling that the most massive galaxies were more abundant and were forming stars more rapidly at early epochs than expected from models. Here we report high-angular-resolution observations of a representative luminous star-forming galaxy when the Universe was only 20% of its current age. A large and massive rotating protodisk is channelling gas towards a growing central stellar bulge hosting an accreting massive black hole. The high surface densities of gas, the high rate of star formation and the moderately young stellar ages suggest rapid assembly, fragmentation and conversion to stars of an initially very gas-rich protodisk, with no obvious evidence for a major merger.

Orbito-cranial injuries caused by penetrating non-missile foreign bodies. Experience with eighteen patients.

BACKGROUND: Penetrating non-missile orbito-cranial injuries are uncommon civilian injuries which have some special features. Only limited case-reports are available in the international literature. METHOD: We present a retrospective review of 18 such in presumed trivial orbital injury. Early identification and removal of retained foreign body fragments was achieved within 36 hours. FINDINGS: Patients were operated on and followed up for at least of 3 years. The final clinical outcome was excellent: 16 had a Glasgow Outcome Scale (GOS) of 5 while in the remaining 2 it was 4. CONCLUSION: The present report indicates that good results, in managing such injuries, can be achieved by a high index of suspicion and early diagnosis of intracranial injury in presumed trivial wounds and by the removal of every possible retained foreign body.

Image-guided microneurosurgical management of vascular lesions using navigated computed tomography angiography. An advanced IGS technology application.

BACKGROUND: Image-guided neurosurgery has become a standard practice in the last few years, with more than 2000 surgical navigation stations installed worldwide. In the same time several reports have also demonstrated the efficacy and accuracy of computed tomography angiography (CTA) in assessing cerebral vascular pathologies. Therefore, the CTA data have recently been implemented into the different navigation systems available on the market, making this new technique widely applied. The objective of this paper is to discuss and evaluate the clinical usefulness of navigated CTA in planning and performing surgery of neurovascular lesions. METHODS: Raw images acquired from an helical CTA are automatically post-processed on an independent workstation by using a three-dimensional (3D) volume-rendering images engine and/or using thresholding and drawing tools. RESULTS: The data obtained provide useful information in the preoperative stage by reconstructing the vascular tree with regard to lesion volume, aneurysm neck, dome projection, perforating vessels and their relationship with the lesion and the surrounding anatomy. Furthermore, it can help in the identification of an arteriovenous malformation (AVM) nidus and recognition of its feeding and draining vessels. CONCLUSION: This fascinating technique can give some invaluable advantages on the management of cerebral vascular lesions and provides excellent information not always available on traditional digital subtraction angiography investigation. It has also proved to be very accurate, particularly regarding the correlation between the 3D volume-rendered CT angiography and the intraoperative findings.

Cervicothoracolumbar pneumorachis. Case report and review of the literature.

BACKGROUND: Pneumorachis is a very rare entity to occur after a major trauma. It is even rarer when its occurrence is not associated with injuries in the skull base, chest, abdomen, pelvis, or spine. Pneumorachis extending through the entire spinal canal has never been reported. CASE DESCRIPTION: We report a case of traumatic air penetration into the spinal canal in a patient, involved in a road traffic accident, who had no apparent major bone and soft tissue injuries. The patient was conscious (Glasgow Coma Scale score of 15/15) upon admission. A cervical lateral x-ray taken the day after admission showed some air in the spinal canal. A subsequent computed tomography with reconstruction disclosed some subdural air extending from the cervical region to the lumbar region. The patient was successfully treated conservatively. The pathogenesis and rarity of this pathology are discussed along with the review of relevant literature. CONCLUSION: Any patient with spinal pneumorachis should be actively investigated to determine if a possible air fistula, which might increase causing spinal cord compression, is present. If a source is not found, a skull base fracture should be suspected.

Non-invasive assessment of extracranial-intracranial bypass grafts using advanced ultrasound technology.

There have been significant developments in ultrasound technology in the last few years which have resulted in an increase in the clinical value of this technique. An illustrative case is presented of how ultrasound technology has been used in the intraoperative and postoperative period to evaluate graft patency and function in patients undergoing extracranial-intracranial bypass graft surgery.

Primary HIV-1 resistance in recently and chronically infected individuals of the Italian Cohort Naive for Antiretrovirals.

The risk of acquiring HIV-1 drug resistance at time of infection has become a public health problem following the widespread use of antiretroviral drugs in developed countries. Although a number of studies have reported data regarding the prevalence of HIV-1 primary resistance in developed countries over the past years, limited knowledge is available regarding the proportion of mutations related to drug resistance in antiretroviral naive subjects with chronic HIV-1 disease. In this study, we evaluated the prevalence of mutations in the reverse-transcriptase (RT) and protease region both in a representative group of recently HIV-1 infected subjects (n=68) and a cohort of chronically-infected HIV-positive patients (n=347) enrolled in the Italian Cohort of Antiretroviral Naive patients (I.CO.NA.). In recently infected individuals, the overall prevalence of mutations for nucleoside RTI (NRTIs) was 10/68 (14.7%). The distribution of mutations by calendar year were 0, 1 in 1996, 9, 3 in 1997 and 1, 0 in 1998 for NRTIs and protease inhibitors (PIs) respectively. Thymidine associated mutations were identified in six subjects (8.8%), five of whom had one mutation [41L, 70K (n=2), 215Y] and one had two mutations (67N+219Q). Four subjects (5.9%) showed the changes associated with resistance to lamivudine (184V or 118I). No non nucleoside-RTI (NNRTI) mutations were present in the study period. Primary PIs mutations (two 46L and two 82I) were present in four subjects (5.9%). Of note, mutations related to resistance to more than one class of antiretrovirals were present in one (1.5%). Among patients with chronic infection a large proportion (88.5%) carried no mutations in RT region, 11.5% individuals carried one or more mutations associated with resistance to NRTI (7.8%), or NNRTI (4.9%), with 4 patients carrying mutations to both classes. Among mutations associated with high-level resistance to RTI, T215Y was found in only 2 patients, M184V in 2 cases, T69D in another case, and K103N in only 1 patient, for a total of 6 patients (one carrying both T215Y and M184V) (1.7%). Primary mutations associated with substantial resistance to PIs were found in only 5/347 patients (1.4%); all the other patients carried only secondary mutations. Prevalence of mutations associated with high-level resistance to antiretroviral drugs is stable in recently infected individuals and low in patients with established HIV infection. The potential impact of transmitted mutations on the response to first regimen in individuals carrying transmitted mutations needs to be assessed by prospective studies.

Central neurocytoma: long-term follow-up of a paediatric case.

In order to gain a better understanding of the clinical and histological features of central neurocytoma and the role of radiotherapy in the treatment of these tumours, we present an unusual paediatric case and review the pertinent literature. Most patients present in the second and third decade of life, rarely in the teenage years and exceptionally in children. Our patient was treated by a combined surgical and radiation therapy treatment for a central neurocytoma at the age of 7 years, but the tumour had been diagnosed when she was 3 years old. At a 38-year follow-up, she is well with no evidence of tumour progression. This patient seems to be the youngest histologically proven case of central neurocytoma and with the longest recorded survival.

Bilateral trigeminal neuralgia: a therapeutic dilemma.

In order to illustrate the inherent problems of managing bilateral trigeminal neuralgia a retrospective study of the 16 cases of bilateral trigeminal neuralgia, out of just over 300 cases of trigeminal neuralgia, treated over a 14-year period, has been performed. All the patients, presented with a typical history of trigeminal neuralgia and underwent surgical exploration. Pain relief was initially achieved in all cases; however, only four remained cured, three have become pain free after additional rhizotomy, a further one after peripheral cryotherapy and four with medical treatment. Four patients have had bilateral operations for trigeminal neuralgia, but in two cases the pain was relieved on one side only. Bilateral trigeminal neuralgia presents special problems of management with respect to underlying neuropathology (e.g. multiple sclerosis), the need for the limitation of the use of ablative techniques in order to minimise the disability of bilateral sensory and motor dysfunction, and the relatively poor response to microvascular decompression. These factors emphasize the multifactorial nature of the cause of trigeminal neuralgia. Magnetic resonance tomographic angiography is now available and is important in determining the range of therapeutic options for this group of patients.

Heterotopic bone formation causing recurrent donor site pain following iliac crest bone harvesting.

An unusual case of recurrent iliac crest donor site pain secondary to heterotopic bone formation is described. The literature is reviewed with a special emphasis on the aetiology and treatment of this entity.

Mutation in the PTEN/MMAC1 gene in archival low grade and high grade gliomas.

The PTEN gene, located on 10q23.3, has recently been described as a candidate tumour suppressor gene that may be important in the development of advanced cancers, including gliomas. We have investigated mutation in the PTEN gene by direct sequence analysis of PCR products amplified from samples microdissected from 19 low grade (WHO Grade I and II) and 27 high grade (WHO grade III and IV) archival, formalin-fixed, paraffin-embedded gliomas. Eleven genetic variants in ten tumours have been identified. Eight of these are DNA sequence changes that could affect the encoded protein and were present in 0/2 pilocytic astrocytomas, 0/2 oligoastrocytomas, 0/1 oligodendroglioma, 0/14 astrocytomas, 3/13 (23%) anaplastic astrocytomas and 5/14 (36%) glioblastomas. PTEN mutations were found exclusively in high grade gliomas; this finding was statistically significant. Only two of the PTEN genetic variants have been reported in other studies; two of the genetic changes are in codons in which mutations have not been found previously. The results of this study indicate that mutation in the PTEN gene is present only in histologically more aggressive gliomas, may be associated with the transition from low histological grade to anaplasia, but is absent from the majority of high grade gliomas.

Multiple meningiomas in different neuraxial compartments. Report of two cases.

Multiple meningiomas in different neuraxial compartments are quite rare. The authors report two new cases of association between cranial and spinal meningiomas, one of them in a patient operated upon for multiple intracranial meningiomas. The first case was a 60-year-old woman with progressive paraparesis who had been operated on 13 years earlier for multiple intracranial meningiomas. A myelo-CT scan showed a block of contrast medium at T1-T2; the lesion was removed via a standard laminectomy. The second patient was a 76-year-old woman with a 6-month history of spastic paraparesis. MRI detected an extramedullary intradural lesion at T6-T7. A cerebral MRI, performed because of the onset of seizures, showed a right parietal lesion. Removal of the thoracic lesion was followed, 6 months later, by removal of the cerebral one. Both patients presented a progressive improvement of the paraparesis and returned to normal daily activities.