Isolated descemetorhexis for anterior synechiolysis prior to endothelial keratoplasty - case report and technique.

To describe the utilization of descemetorhexis for reformation of the anterior chamber in eyes with central iridocorneal synechiae before endothelial keratoplasty (EK). A 71-year-old man with a history of trabeculectomy complicated by hypotony presented with bullous keratopathy in the presence of extensive iridocorneal synechiae and a flat anterior chamber. In order to proceed with EK, synechiolysis with the use of viscoelastic and scissors was attempted. Despite successful dissection of the peripheral strands, the pupillary margin of the iris remained attached to the endothelium. Therefore, descemetorhexis was performed to detach the Descemet membrane along with central synechiae and create sufficient space for safe EK at a later stage. Corneal clarity was restored by ultrathin Descemet stripping automated endothelial keratoplasty, leaving a fibrous membrane in the pupillary plane, which was excised 2 months later, allowing an improvement of best-corrected visual acuity to 0.5. Isolated descemetorhexis was successfully employed to reform the anterior chamber and proceed with EK in a case of bullous keratopathy and resistant iridocorneal synechiae. This stepwise approach may be considered in similar cases in order to avoid a more invasive treatment, ie, penetrating keratoplasty and synechiolysis

Dynamics of Alpha-Helix Formation in the CSAW Model

We study the folding dynamics of polyalanine (Ala$_{20}$), a protein fragment with 20 residues whose native state is a single alpha helix. We use the CSAW model (conditioned self-avoiding walk), which treats the protein molecule as a chain in Brownian motion, with interactions that include hydrophobic forces and internal hydrogen bonding. We find that large scale structures form before small scale structures, and obtain the relevant relaxation times. We find that helix nucleation occurs at two separate points on the protein chain. The evolution of small and large scale structures involve different mechanisms. While the former can be describe by rate equations governing the growth of helical content, the latter is akin to the relaxation of an elastic solid.Comment: 18 pages, 10 figure

Retro-oesophageal right subclavian artery in association with thyroid ima artery: a case report, clinical impact and review of the literature

A 37-year-old female Caucasian cadaver with an aberrant right subclavian artery extending from the left side of the aortic arch and following a retro-oesophageal course is presented. A non-recurrent right laryngeal nerve and a thyroid ima artery arising from the lower part of the middle third of the right common carotid artery coexisted. The brachiocephalic trunk was absent, while both common carotid arteries and left subclavian artery followed their normal course. The aim of the current study is to highlight the clinical impact of the above abnormalities providing useful and practically applicable knowledge to interventional clinicians, thoracic and neck surgeons, since the vast majority of documented cases with an arteria lusoria are clinically silent and in most cases discovered incidentally. Clinical manifestations such as dysphagia, chronic cough, and acute ischaemia to the right upper limb may occur, leading to misinterpretation in radiographic examination and complications during neck and thoracic surgery. Review of the literature was also performed and the embryological background of the aberration is highlighted

An atypical biceps brachii and coracobrachialis muscles associated with multiple neurovascular aberrations: a case report with clinical significance

Neural and vascular variations in the axilla and upper limb area are usually paired, but coexistence of muscular aberration on top of this is uncommon. The current case report emphasizes on the unilateral coexistence of a three-headed (tricipital) biceps brachii muscle, a two-headed coracobrachialis with an accessory muscle bundle joining the superficial and deep heads of coracobrachialis muscle. On the ipsilateral side of the 72-year-old male cadaver, a connecting branch originated from the musculocutaneous nerve and joined the median nerve after surpassing the accessory muscle bundle. A large diameter subscapular trunk originated from the 2nd part of the axillary artery and after giving off the 1st lateral thoracic artery trifurcated into a common stem which gave off the 2nd and 3rd lateral thoracic arteries, the circumflex scapular artery and a common branch that gave off the 4th and 5th lateral thoracic arteries and the thoracodorsal artery, as the ultimate branch. All lateral thoracic arteries were accompanied by multiple intercostobra- chial nerves. Documentation of such muscular and neurovascular variants and their embryologic origin increases awareness of their potential impact on diagnosis and treatment of upper limb pathology. To the best of our knowledge, the currently reported cadaveric observations seem to constitute a unique finding.

Transtendinous course of the infrapatellar branch of saphenous nerve. A contribution to the aetiology of entrapment neuropathy and modification of the existing classification

Background: The course of the infrapatellar branch of saphenous nerve (IPBSN) in relation to the Sartorius muscle has been classified into presartorial, transsartorial and retrosartorial types. Mechanical compression of the IPBSN within the Sartorius tendon has been surgically recognised as a cause of entrapment neuropathy. Purpose of the present study was to differentiate the IPBSNs penetrating the Sartorius tendon from those penetrating the Sartorius muscle, from an anatomical and clinical point of views and thus modifying the existing classification. Materials and methods: The IPBSN was bilaterally dissected in 27 cadavers. The cases of the IPBSNs penetrating the Sartorius tendon were recorded separately from those penetrating the Sartorius muscle belly. Results: In 11 out of 54 limbs (20.4%) the IPBSN ran through the Sartorius muscle belly. In 3 out of 54 (5.6%) limbs, the IPBSN penetrated the Sartorius tendon. Conclusions: The penetrating type of IPBSN includes two distinct subtypes: the muscle-penetrating type and the tendon-penetrating type. These subtypes are also distinct from a clinical point of view, since only the tendon-penetrating type has been associated with the IPBSN entrapment neuropathy. According to these findings we suggest a modification of the current classification. Further clinical studies are necessary to fully demonstrate whether the tendon-penetrating type should be considered as a predisposing factor for the IPBSN entrapment neuropathy. Distinguishing the two subtypes might be helpful for that purpose

Simultaneous multi-frequency single-pulse properties of AXP XTE J1810-197

We have used the 76-m Lovell, 94-m equivalent WSRT and 100-m Effelsberg radio telescopes to investigate the simultaneous single-pulse properties of the radio emitting magnetar AXP XTE J1810-197 at frequencies of 1.4, 4.8 and 8.35 GHz during May and July 2006. We study the magnetar's pulse-energy distributions which are found to be very peculiar as they are changing on time-scales of days and cannot be fit by a single statistical model. The magnetar exhibits strong spiky single giant-pulse-like subpulses, but they do not fit the definition of the giant pulse or giant micropulse phenomena. Measurements of the longitude-resolved modulation index reveal a high degree of intensity fluctuations on day-to-day time-scales and dramatic changes across pulse phase. We find the frequency evolution of the modulation index values differs significantly from what is observed in normal radio pulsars. We find that no regular drifting subpulse phenomenon is present at any of the observed frequencies at any observing epoch. However, we find a quasi-periodicity of the subpulses present in the majority of the observing sessions. A correlation analysis indicates a relationship between components from different frequencies. We discuss the results of our analysis in light of the emission properties of normal radio pulsars and a recently proposed model which takes radio emission from magnetars into consideration.Comment: 15 pages, 11 figures, accepted for publication by MNRA

Incidence, number and topography of Wormian bones in Greek adult dry skulls

Background: Wormian bones (WBs) are irregularly shaped bones formed from independent ossification centres found along cranial sutures and fontanelles. Their incidence varies among different populations and they constitute an anthropo- logical marker. Precise mechanism of formation is unknown and being under the control of genetic background and environmental factors. The aim of the current study is to investigate the incidence of WBs presence, number and topographical distribution according to gender and side in Greek adult dry skulls.  Materials and methods: All sutures and fontanelles of 166 Greek adult dry skulls were examined for the presence, topography and number of WBs. One hundred and nineteen intact and 47 horizontally craniotomised skulls were examined for WBs presence on either side of the cranium, both exocranially and intracranially.  Results: One hundred and twenty-four (74.7%) skulls had WBs. No difference was detected between the incidence of WBs, gender and age. Sutures and fon- tanelles located in neurocranium showed a higher incidence of WBs, contrariwise to orbital sutures that indicated a low incidence. WBs most commonly located in the lambdoid suture (44.6%), followed in order of frequency by the coronal suture (39.8%), asterion (21% on the left and 15.3% on the right side) and parie- tomastoid suture (15.1% on the left and 13.9% on the right side). Other sutures with WBs were the occipitomastoid, sagittal, squamosal, zygomaticosphenoid, metopic, frontonasal and frontozygomatic. Regarding the skull fontanelles, WBs were found at pterion, posterior and anterior fontanelles.  Conclusions: The current study highlights a high incidence of WBs in a Greek population, indicating racial variation. The in depth knowledge of exact location, frequency and number of WBs is essential for clinicians intervening in the skull area, anthropologists and forensic surgeons investigating child abuse cases.

Persistent median artery in the carpal tunnel: anatomy, embryology, clinical significance, and review of the literature

The median artery usually regresses after the eighth week of intrauterine life, but in some cases it persists into adulthood. The persistent median artery (PMA) passes through the carpal tunnel of the wrist, accompanying the median nerve. During anatomical dissection in our department, we found two unilateral cases of PMA originating from the ulnar artery. In both cases the PMA passed through the carpal tunnel, reached the palm, and anastomosed with the ulnar artery, forming a medio-ulnar type of superficial palmar arch. In addition, in both cases we observed a high division of the median nerve before entering the carpal tunnel. Such an artery may result in several complications such as carpal tunnel syndrome, pronator syndrome, or compression of the anterior interosseous nerve. Therefore, the presence of a PMA should be taken into consideration in clinical practice. This study presents two cases of PMA along with an embryological explanation, analysis of its clinical significance, and a review of the literature. The review of the literature includes cases observed during surgical procedures or anatomical dissections. Cases observed by means of imaging techniques were not included in the study

Investigation of the styloid process length in a Greek population

Background: The styloid process (SP) is a slender cylindrical bony projection of the temporal bone with 2 ligaments and 3 muscles attached to it. Symptomatic SP elongation is also referred to, as Eagle’s syndrome. The aim of the present study is to investigate the distribution of the SP length in a young adult Greek population.  Materials and methods: Moreover, we provide a comparison of the results by using two different methods for assessing SP elongation, as described in the lite- rature. Finally, we explore the possibility of using orthopantomograms (OPGs), as a diagnostic aid by investigating inter-examiner, intra-examiner and inter-exami- nation variability and we propose a limit for SP elongation measurable in OPGs.  Results: The sample comprised 805 digital OPGs, taken from student pilots and engineers entering the Hellenic Air Force Academy, from 2008 onwards. Two measuring approaches were selected, one using the temporal bone, as a cranial landmark and the other, using the external auditory meatus. The end tip of the process was always the caudal landmark. The mean SP length was 28.42 ± ± 8.48 mm in males and 26.04 ± 7.69 mm in females, when measured from the temporal bone. The mean SP length was 38.35 ± 8.90 mm in males and 34.24 ± ± 8.63 mm in females, when measured from the external auditory meatus. The length of 30 mm is most commonly used as a starting point for SP elongation. In the total sample, 30.6% of the measured SPs exceeded the length of 30 mm. In males, 33.12% of the SPs were elongated; while in females the corresponding incidence was 20%. One hundred and nineteen (14.8%) SPs were not traceable.  Conclusions: The SP is typically detectable and measurable in OPGs. An elonga- ted SP should be kept in mind, since symptoms of elongation may overlap with clinical manifestations of temporomandibular joint disorders.