Does the treatment of normal pressure hydrocephalus put the retinal ganglion cells at risk? A brief literature review and novel hypothesis

Normal pressure hydrocephalus (NPH) is a poorly understood entity as well as a source of continuous controversy in the neuroscientific community. The surgical management of this disease requires that intracranial pressure (ICP), also referred to as the cerebrospinal fluid pressure (CSFP), be lowered using a cerebrospinal fluid (CSF) diversion procedure. Numerous complications are linked with this procedure; we believe that new evidence suggests that the induction or acceleration of glaucomatous optic neuropathy are possible sequelae that warrant further investigation. We also suggest potential solutions derived from the increased understanding of the disease’s pathophysiology and new advances in imaging of the optic nerve head complex.     

Future ophthalmology practice pattern: A survey of Saudi Board of Ophthalmology residents

Purpose

The main purpose of the study was to examine and identify factors that influence the future practice pattern of Saudi Board of Ophthalmology residents as well as their academic goals. This study also aimed to compare the plans and career goals of the current Saudi ophthalmology residents with a former cohort of Saudi ophthalmology residents.

A method for stabilizing a lingual fixed retainer in place prior to bonding

AIM: The objective of this article is to present a simple technique for stabilizing a lingual fixed retainer wire in place with good adaptation to the teeth surfaces and checking for occlusal interferences prior to the bonding procedure. BACKGROUND: Bonding of an upper or lower fixed lingual retainer using stainless steel wires of different sizes and shapes is a common orthodontic procedure. The retainer can be constructed in a dental laboratory, made at chair side, or it can be purchased in prefabricated form. All three ways of creating a fixed retainer are acceptable. However, the method of holding the retainer wire in place adjacent to the lingual surfaces of the teeth before proceeding with the bonding process remains a problem for some practitioners. REPORT: The lingual fixed retainer was fabricated using three pieces of .010" steel ligature wire which were twisted into a single strand wire. Another four to five 0.010" pieces of steel ligature wires were twisted in the same way to serve as an anchor wire from the labial side of the teeth. The retainer wire was bonded using the foible composite. SUMMARY: The technique presented here for stabilizing the retainer wire prior to bonding provides good stabilization, adaptation, and proper positioning of the retainer wire while eliminating contamination of etched surfaces which might arise during wire positioning before bonding. This technique also allows the clinician the opportunity to check the occlusion and adjust the retainer wire to avoid occlusal interference prior to bonding maxillary retainers. This same clinical strategy can be used to stabilize wires for splinting periodontally affected teeth and traumatized teeth.     

Trauma induces a hypercoagulable state that is resistant to hypothermia as measured by thrombelastogram

Background

The aim of this study was to test the hypothesis that severely injured trauma patients would be hypercoagulable compared with controls measured by thromboelastography and that this hypercoagulability would persist over a broad range of temperatures.

Methods

A prospective study evaluating the effects of temperature on coagulation in trauma patients with Injury Severity Scores ≥ 15 and controls was completed. Thromboelastography was performed 24 hours after admission at 4 temperatures ranging from 32°C to 38°C.

Results

Ninety-two subjects (46 patients) were analyzed. Patients had a median Injury Severity Score of 20 (interquartile range, 16–26). Time to clot formation increased (P < .001) and fibrin cross-linking decreased (P < .01) in both groups as temperature decreased. Between groups, time to clot formation, fibrin cross-linking, and clot strength were significantly different at each temperature (P < .01), with patients being more hypercoagulable. Time to clot formation and fibrin cross-linking were more affected by temperature in controls compared with patients (P < .02).

Conclusions

Severely injured patients are more hypercoagulable than controls throughout a broad range of temperature. Decreasing temperature has a greater effect on coagulation in controls compared with patients.     

Challenges in the diagnosis of microbial keratitis: A detailed review with update and general guidelines

The incidence of microbial keratitis (MK) is variable worldwide with an estimated 1.5–2 million cases of corneal ulcers in developing countries. The complications of MK can be severe and vision threatening. Therefore, proper diagnosis of the causative organism is essential for early successful treatment. Accurate sampling of microbiological specimens in MK is an important step in identifying the infective organism. Corneal scrapping, tear samples and corneal biopsy are examples of specimens obtained for the investigative procedures in MK. Ophthalmologists especially in an emergency room setting should be aware of the proper sampling techniques based on their microbiology-related basic information for each category of MK. This review article briefly describes the clinical presentation and defines in details the best updated diagnostic methods used in different types of MK. It can be used as a guide for ophthalmology trainees and general ophthalmologists who may be handling such cases at initial presentation.     

Anatomical and molecular mapping of the left and right ventricular His-Purkinje conduction networks

Functioning of the cardiac conduction system depends critically on its structure and its complement of ion channels. Therefore, the aim of this study was to document both the structure and ion channel expression of the left and right ventricular His–Purkinje networks, as we have previously done for the sinoatrial and atrioventricular nodes. A three-dimensional (3D) anatomical computer model of the His–Purkinje network of the rabbit heart was constructed after staining the network by immunoenzyme labelling of a marker protein, middle neurofilament. The bundle of His is a ribbon-like structure and the architecture of the His–Purkinje network differs between the left and right ventricles. The 3D model is able to explain the breakthrough points of the action potential on the ventricular epicardium during sinus rhythm. Using quantitative PCR, the expression levels of the major ion channels were measured in the free running left and right Purkinje fibres of the rabbit heart. Expression of ion channels differs from that of the working myocardium and can explain the specialised electrical activity of the Purkinje fibres as suggested by computer simulations; the expression profile of the left Purkinje fibres is more specialised than that of the right Purkinje fibres. The structure and ion channel expression of the Purkinje fibres are highly specialised and tailored to the functioning of the system. The His–Purkinje network in the left ventricle is more developed than that in the right ventricle and this may explain its greater clinical importance.     

Intraoperative blood transfusion in pediatric patients undergoing renal transplant—Effect of renal graft size

In pediatric RT, donor allograft size often exceeds the expected recipient norms, especially in younger recipients. An “oversize” graft might not only present a technical‐ and space‐related challenge, but may possibly lead to increased demands in perioperative volume requirements due to the disparity between donor and recipient in renal blood flow. We evaluated transfusion practices at a single tertiary institution with special consideration of kidney graft size, hypothesizing that oversize graft kidneys might lead to a quantifiable increased need of blood transfusion in smaller recipients. Retrospective analysis of all patients who underwent pediatric RT from January 2004 to June 2014 at a tertiary pediatric centre was performed. Variables analyzed included patient age, weight, pre‐ and postoperative Hb concentration, graft size, EBL, amount of intraoperative blood transfusion, and preoperative use of erythropoietin. Based on graft size in relation to patient's age, a SMR and an OvR were identified. A subcohort of age‐matched pairs was used to allow for comparison between groups. We calculated the expected procedure‐ and transfusion‐induced changes in Hb and compared these changes to the observed difference in pre‐ vs postoperative Hb to assess the influence of graft size on transfusion requirements. RT was performed in 188 pediatric recipients during the study period. In the matched cohort, percentage of transfused patients during transplantation in the OvR group was more than double compared with SMR (89% vs 39%, P < .001); similarly, the median number of transfused PRBC units in OvR was 1, while the median of SMR did not receive transfusion (P < .001). The difference between expected (calculated) and observed change in Hb was significantly higher in OvR with a median of 1.9 g/dL compared with SMR with a median of 1.0 g/dL (P = .026). Correspondingly, the calculated median volume taken up by a regular size kidney was significantly higher with 213 mL compared with 313 mL (P = .031) taken up by an oversize graft kidney. Median estimated intraoperative blood loss was significantly higher in OvR than in SMR (6.9 mL/kg, vs 5.3 mL/kg, respectively; P = .04). Median postoperative Hb was similar among groups (10.4 g/dL vs 10.6 g/dL for SMR vs OvR, respectively). Transplantation of an oversized kidney in pediatric RT recipients is associated with a quantifiable higher need for blood transfusion. This may be caused by a higher intraoperative EBL and/or greater blood volume sequestered by the larger renal allograft and requires further evaluation.