Evaluation of Distal Tibiofibular Interosseous Ligament Angle and Its Relevance in Syndesmosis Fixation

Category:

Ankle; Basic Sciences/Biologics

Introduction/Purpose:

The interosseous ligament (IOL) of the ankle, together with the anterior and posterior inferior tibiofibular ligament (ATFL and PITFL), are important structures which stabilizes the inferior tibiofibular joint. Besides securing the fibula tightly to tibia, these ligaments prevent excessive lateral fibular displacement and external talar rotation. Thus, any injury to either bone or ligaments at this level will result in instability and abnormal joint motion. Our study aims to evaluate the anatomical angle of the ankle interosseous ligament on magnetic resonance imaging (MRI) studies to better understand the biomechanical forces that act within the distal tibiofibular joint, relevance of assimilating the anatomical angle and its relevance in syndesmosis fixations.

Methods:

MRIs of ankles were chosen anonymously from the global PACS system database between the months September to October 2020. A total of 34 patients' MRIs were identified. Patients who sustained bone or soft tissue injury at the level of ankle syndesmosis were excluded to avoid any ambiguity in altered position of the IOL due to trauma. The angle of interosseous ligament from the tibial plafond was measured on the coronal plane. The axial plane was used as a reference to ensure correct position of measurement. This was done in collaboration with radiologists to ensure that IOL is correctly identified, prior to start of the study. The angle was measured separately by two different investigators and the average angle was obtained for each MRI. Data was tabulated and statistical analysis was done.

Results:

All of the 20 ankles identified during the study period were included in the analysis. There were 10 male and 10 female patients. Nine were left ankles and 11 were right ankles. The median age was 54 years (range 14 - 83). The mean IOL angle was 65.66 degrees. The standard error of difference between the 2 investigators was 0.567 and the two-tailed P value was 0.4980. By conventional criteria, this difference is considered to be not statistically significant.

Conclusion:

The ligament angle formed against tibial plafond bears theoretical relevance. We propose further cadaveric studies to confirm IOL anatomical ligament angle and carrying out implant failure stress test in a lab between the implant inserted parallel to the normal angle of IOL (65 degrees) vs 90 degrees. We also propose that such studies may show that all implants to stabilize the syndesmosis may be more effective if we try to reproduce nature by replicating as close to the IOL's anatomical angle rather than using a long held dogma of fixing syndesmosis to neutralize the forces as nature intended.

Intraosseous device for arthrodesis in foot and ankle surgery: Review of the literature and biomechanical properties

BACKGROUND

Arthrodesis is the surgical fusion of a diseased joint for the purposes of obtaining pain relief and stability. There have been numerous fixation devices described in literature for foot and ankle arthrodesis, each with their own benefits and drawbacks.

AIM

To review the use of intraosseous devices in foot and ankle surgery.

METHODS

There were 9 papers included in the review (6 clinical and 3 experimental studies) all evaluating arthrodesis in the foot and ankle using the IOFIX device (Extremity Medical™, Parsippany, NJ, United States). Outcome scores, union rates, as well as complications were analysed.

RESULTS

IOFIX appears to be safe and effective in achieving arthrodesis of the 1^st metatarsophalangeal, and talonavicular joints with early rehabilitation. In comparison to plate/screw constructs there were fewer soft tissue complications and issues of metalwork prominence. Cadaveric and biomechanical studies on the use of intramedullary fixation for fusion of the tarsometatarsal and ankle joint showed decreased load to failure, cycles to failure and stiffness in comparison to traditional fusion methods using plates and screws, however IOFIX devices produced higher compressive forces at the joint.

CONCLUSION

We describe the reasons for which this biomechanical behavior of the intraosseous fixation may be favorable, until prospective and comparative studies with larger sample size and longer follow-up confirm the effectiveness and limitations of the method.

Management of limb length problems during total hip arthroplasty for patients with developmental dysplasia of the hip

The anatomy of the acetabulum and femur is usually significantly altered in people with developmental dysplasia of the hip and this leads to secondary osteoarthritis of the hip joint. Ideal positioning of implants and reduction of the joint is technically demanding during arthroplasty. Lengthening may result in nerve palsies and therefore procedures may have to be undertaken to shorten the femur. Other complications include dislocation and non-union at the shortening osteotomy site. Thorough preoperative planning and templating is required before surgery to assess the need for shortening. Shortening osteotomies can be performed at the proximal femur, diaphysis or distal femoral levels, with subtrochanteric being the most common level. The procedure should be customised for each patient after extensive planning and detailed counselling.

Does Platelet-rich Plasma Augmentation Following Hip Arthroscopy Improve Outcomes: A Systematic Review

Platelet-rich plasma (PRP) has gathered widespread acceptance among orthopaedic surgeons because of its multimodal effects on tissue healing. Varying results have been reported when PRP injections are combined with hip arthroscopic surgery. To evaluate the influence of PRP on clinical outcomes following hip arthroscopy. We hypothesized that patients treated with PRP would have improved postoperative outcome scores. A search of the National Institute for Health and Care Excellence (NICE) healthcare database advanced search (HDAS) via Athens (PubMed, MEDLINE, CINAHL, EMBASE, and AMED databases) was conducted from their years of inception to May 2018 with the keywords: "Hip Arthroscopy" and "Platelet-Rich Plasma". A quality assessment was performed based on the Cochrane risk of bias tool. Three studies were included for analysis; two of which had low risk of bias. The studies included 363 hips, of which 141 were randomised for PRP treatment. The mean age of all patients was 35 years and the follow-up ranged from 18.5 to 36 months. Authors used different PRP systems and preparations. Modified Harris hip score was reported in all three studies with two studies favouring the use of PRP. The use of PRP following hip arthroscopy did not lead to significantly improved postoperative pain or functional outcomes when compared to control groups in the studies included in this review.

Hematological Effects of Non-Homogenous Ionizing Radiation Exposure in a Non-Human Primate Model

Detonation of a radiological or nuclear device in a major urban area will result in heterogenous radiation exposure, given to the significant shielding of the exposed population due to surrounding structures. Development of biodosimetry assays for triage and treatment requires knowledge of the radiation dose-volume effect for the bone marrow (BM). This proof-of-concept study was designed to quantify BM damage in the non-human primate (NHP) after exposure to one of four radiation patterns likely to occur in a radiological/nuclear attack with varying levels of BM sparing. Rhesus macaques (11 males, 12 females; 5.30-8.50 kg) were randomized by weight to one of four arms: 1. bilateral total-body irradiation (TBI); 2. unilateral TBI; 3. bilateral upper half-body irradiation (UHBI); and 4. bilateral lower half-body irradiation (LHBI). The match-point for UHBI vs. LHBI was set at 1 cm above the iliac crest. Animals were exposed to 4 Gy of 6 MV X rays. Peripheral blood samples were drawn 14 days preirradiation and at days 1, 3, 5, 7 and 14 postirradiation. Dosimetric measurements after irradiation indicated that dose to the mid-depth xiphoid was within 6% of the prescribed dose. No high-grade fever, weight loss >10%, dehydration or respiratory distress was observed. Animals in the bilateral- and unilateral TBI arms presented with hematologic changes [e.g., absolute neutrophil count (ANC) <500/ll; platelets <50,000/ll] and clinical signs/symptoms (e.g., petechiae, ecchymosis) characteristic of the acute radiation syndrome. Animals in the bilateral UHBI arm presented with myelosuppression; however, none of the animals developed severe neutropenia or thrombocytopenia (ANC remained >500/µl; platelets >50,000/µl during 14-day follow-up). In contrast, animals in the LHBI arm (1 cm above the ilieac crest to the toes) were protected against BM toxicity with no marked changes in hematological parameters and only minor gross pathology [petechiae (1/5), splenomegaly (1/5) and mild pulmonary hemorrhage (1/5)]. The model performed as expected with respect to the dose-volume effect of total versus partial-BM irradiation, e.g., increased shielding resulted in reduced BM toxicity. Shielding of the major blood-forming organs (e.g., skull, ribs, sternum, thoracic and lumbar spine) spared animals from bone marrow toxicity. These data suggest that the biological consequences of the absorbed dose are dependent on the total volume and pattern of radiation exposure.

A functional comparison of medial pivot and condylar knee designs based on patient outcomes and parameters of gait

Aims

The outcome of total knee arthroplasty (TKA) is not always satisfactory. The purpose of this study was to identify satisfaction and biomechanical features characterising the gait of patients who had undergone TKA with either an anatomical single radius design or a medial pivot design. We hypothesised that the latter would provide superior function.

Patients and Methods

This is a study of a subset of patients recruited into a prospective randomised study of a single radius design versus a medial pivot design, with a minimum follow-up of one year. Outcome measurements included clinical scores (Knee Society Score (KSS) and Oxford Knee Score (OKS)) and gait analysis using an instrumented treadmill.

Results

There was no statistically significant difference between the two groups for both the KSS and OKS. There was also no statistical significance in cadence, walking speed, stride length and stance time, peak stride, mid support and push-off forces.

Conclusion

This study corroborates a previous study by the same authors that showed equally good results in clinical outcome and gait between the conventional single radius and medial pivot designs under stringent testing conditions.

Cite this article: Bone Joint J 2018;(1 Supple A)100-B:76–82.

Approaches towards the development of chimeric DPP4/ACE inhibitors for treating metabolic syndrome

Designing drug candidates exhibiting polypharmacology is one of the strategies adopted by medicinal chemists to address multifactorial diseases. Metabolic disease is one such multifactorial disorder characterized by hyperglycaemia, hypertension and dyslipidaemia among others. In this paper we report a new class of molecular framework combining the pharmacophoric features of DPP4 inhibitors with those of ACE inhibitors to afford potent dual inhibitors of DPP4 and ACE.

Role of the Whole Body Vibration Machine in the Prevention and Management of Osteoporosis in Old Age: A Systematic Review

A literature search of related articles was carried out in electronic data sources. Initially, 276 randomised controlled trials related to the title were collected, after which 44 were selected using the keywords. Overlapping articles, articles with a study duration of less than six months, and studies involving young participants were removed from the list. The remaining 20 articles were checked for entitlement using the PEDro scale. A total of nine eligible articles with 1486 participants were analysed. Seven trials used dual-energy x-ray absorptiometry (DXA) to measure bone mineral density (BMD). The six trials published from 2005 to 2013 found a significant increase in BMD. In the remaining one trial, there was no significant increase in BMD. One study published in 2013 reported a significant increase in BMD measured with peripheral qualitative computed tomography, whereas another trial published in 2014 stated that there was a reduction in calcaneal bone density measured by peripheral qualitative ultrasound. From these findings it can be concluded that the whole body vibration machine is a good adjunctive therapy for the prevention and management of osteoporosis in postmenopausal women. However, further investigations are necessary before the same can be recommended for elderly men.

Review on the comparison of effectiveness between denosumab and bisphosphonates in post-menopausal osteoporosis

Objectives

Osteoporosis is a rapidly rising cause of concern for elderly patients. Various classes of drugs are available in the market. Bisphosphonates are considered as a first-line therapy for the prevention and treatment. Denosumab is an antiresorptive agent which is a RANK ligand inhibitor. There is a scarcity of comparison between these two classes of drugs. The aim of this study is to compare efficacy of Bisphosphonates and Denosumab in various parameters.

Methods

Literature search was done for randomized controlled trials (RCTs) comparing bisphosphonates with denosumab. RCTs with a treatment period of at least one year with a baseline bone mineral density (BMD) and bone turnover markers (BTM) and follow up values at one year were included in the study. All included studies were also analysed for complications. The study has also been registered in PROSPERO International prospective register of systematic reviews.

Results

A total of five RCTs were identified providing data on 3751 participants. In all five studies, the BMD changes at both hip and spine were statistically significant in favour of denosumab. Result was similar in three studies that studied BMD changes at the wrist. Denosumab also produced significant reduction in BTM as early as one month, but at one year there was no difference compared to the bisphosphonates. There was no statistically significant differences in the complication rates.

Conclusions

Though both bisphosphonates and denosumab were effective with similar side effects, the latter was statistically superior in increasing the BMD and reducing the BTM.

Biological evaluation of RBx-0128, a potent and selective dipeptidyl peptidase-IV inhibitor in type 2 diabetes genetic model

AIM

Dipeptidyl peptidase IV (DPP-IV) inhibition to modulate the incretin effect is a proven strategy to treat type 2 diabetes mellitus. The present study describes the pharmacological profile of a novel DPP-IV inhibitor RBx-0128, as an antidiabetic agent.

MATERIAL AND METHODS

DPP-IV assay was carried out to evaluate in vitro potency of RBx-0128 using human, mouse, and rat plasma as an enzyme source. Selectivity was assessed with various serine proteases. In vivo efficacy was assessed in ob/ob mice. The pharmacokinetic (PK) profile was performed in Wistar rats.

RESULTS

RBx-0128 inhibited human, mouse, and rat plasma DPP-IV activity with IC50 values of 10.6, 18.1, and 56.0 nM respectively, selective over various serine proteases (900-9000-fold). The inhibition was reversible and competitive in nature. In ob/ob mice, RBx-0128 significantly (P<0.05) inhibited plasma DPP-IV and stimulated GLP-1 and insulin at 10 mg/kg. In the oral glucose tolerance test (OGTT), glucose lowering effect was better than sitagliptin (23 vs. 17%) at 10 mg/kg. The effect was sustained till 8 hours (30-35%) at 10 mg/kg with favorable PK profile (plasma clearance: 39.3 ml/min/kg; Cmax 790 ng/ml; t1/2 1.6 hours; tmax 4.8 hours, Vss 3.24 l/kg and Foral 55%) in Wistar rats.

CONCLUSIONS

The present study showed that RBx-0128 is a novel, DPP-IV inhibitor with an antihyperglycemic effect. It can be a promising candidate for the treatment of type 2 diabetes mellitus.

A CT-based classification of prior ACL femoral tunnel location for planning revision ACL surgery

PURPOSE

The purposes of this study are to describe an ACL femoral tunnel classification system for use in planning revision ACL reconstruction based on 3-D computed tomography (CT) reconstructions and to evaluate its inter- and intra-rater reliability.

METHODS

A femoral tunnel classification system was developed based on the location of the femoral tunnel relative to the lateral intercondylar ridge. The femoral tunnel was classified as Type I if it was located entirely below and posterior to the ridge as viewed from distally, Type II if it was slightly malpositioned (either vertically, anteriorly, or both), and Type III if it was significantly malpositioned. To evaluate the reproducibility of the classification system, CT scans of 27 knees were obtained from patients scheduled for revision ACL reconstruction, and 3-D reconstructions were created. Four views of the 3-D reconstruction of each femur were then obtained, and inter- and intra-observer reliability was determined following classification of the tunnels by eight observers.

RESULTS

Twenty-five tunnels were classified as Type I (5 tunnels), Type II (9 tunnels), or type III (11 tunnels) by at least 5 of 8 observers, while insufficient agreement was noted to classify two tunnels. The interobserver reliability of tunnel classification as type I, II, or III yielded a κ coefficient of 0.57, while intra-observer reliability yielded a κ coefficient of 0.67. Subclassification of type II femoral tunnels into the subgroups anterior, vertical, and both was possible in four of the nine type II patients. The interobserver reliability of the complete classification system yielded a κ coefficient of 0.50, while the intra-observer reliability yielded a κ coefficient of 0.54.

CONCLUSION

Classification of the location of ACL femoral tunnels utilizing 3-D reconstructions of CT data yields moderate to substantial inter- and intra-observer reliability.

LEVEL OF EVIDENCE

Diagnostic Level III.

Development of lipid-based nanoparticles for enhancing the oral bioavailability of paclitaxel

The current research work investigates the potential of solid lipid nanoparticles (SLNs) in improving the oral bioavailability of paclitaxel. Paclitaxel-loaded SLNs (PTX-SLNs) were prepared by modified solvent injection method using stearylamine as lipid, soya lecithin and poloxamer 188 as emulsifiers. SLNs were characterized in terms of surface morphology, size and size distribution, surface chemistry and encapsulation efficiency. Pharmacokinetics and bioavailability studies were conducted in male Swiss albino mice after oral administration of PTX-SLNs. SLNs exhibited spherical shape with smooth surface as analyzed by transmission electron microscopy (TEM). The mean particle size of SLNs was 96 ± 4.4 nm with a low polydispersity index of 0.162 ± 0.04 and zeta potential of 39.1 ± 0.8 mV. The drug entrapment efficiency was found to be 75.42 ± 1.5% with a loading capacity of 31.5 ± 2.1% (w/w). Paclitaxel showed a slow and sustained in vitro release profile and followed Higuchi kinetic equations. After oral administration of the PTX-SLNs, drug exposure in plasma and tissues was ten- and twofold higher, respectively, when compared with free paclitaxel solution. PTX-SLNs produced a high mean C (max) (10,274 ng/ml) compared with that of free paclitaxel solution (3,087 ng/ml). The absorbed drug was found to be distributed in liver, lungs, kidneys, spleen, and brain. The results suggested that PTX-SLNs dispersed in an aqueous environment are promising novel formulations that enhanced the oral bioavailability of hydrophobic drugs, like paclitaxel and were quite safe for oral delivery of paclitaxel as observed by in vivo toxicity studies.

Integration of physicochemical and pharmacokinetic parameters in lead optimization: a physiological pharmacokinetic model based approach

There have been major strides in the development of novel ways of investigating drug like properties of new chemical entities (NCE) in the last three decades. Identification of ideal properties of a clinical candidate that would give a clinical proof of concept (POC) is the most critical step in the discovery process. Besides the biological dose-response relationship, the pharmacokinetic parameters play the most vital role in influencing the therapeutic response or toxicity of NCE. While there are numerous techniques to understand various drug-like properties individually, the behavior of an NCE in a dynamic in vivo system which influences its therapeutic or toxic effects is a composite function of its various physicochemical and pharmacokinetic parameters. This implies the need to understand the collective influence of various measured parameters, and knowing how variations made in them can result in favorable pharmacodynamic or toxicokinetic properties. Understanding this behavior holds the key to a successful and time efficient lead optimization process. Physiological based pharmacokinetic models (PBPK) are of great interest in this context as they involve a natural way of integrating the individual compound property to physiological properties, providing a rational approach to predict drug like behavior (an ideal behavior identified may be addressed generally as Target Product Profile) in vivo. In the current review, various physiological pharmacokinetic models addressing absorption, tissue distribution and clearance are discussed along with their application in integrating various physicochemical and ADME parameters to predict human pharmacokinetics helping lead optimization.

Enhanced expression of recombinant proteins utilizing a modified baculovirus expression vector

The baculovirus expression vector system (BEVS) has been widely used for over-expressing eukaryotic proteins due to a close resemblance in post-translational modification, processing, and transportation properties of the expressed protein, to that of the mammalian cells. In comparison to the bacterial expression system, protein yield from BEVS is relatively low, resulting in higher cost of production. To improve the existing recombinant protein expression levels, baculovirus homologous region1 (hr1) was strategically integrated into the bacmid-based transfer vectors. Luciferase reporter, human Protein Kinase B-alpha (PKB-A), and N-terminal-modified CYP-1A2 genes were independently cloned in non-hr1 and hr1 constructs for generating respective bacmids and baculoviruses. These recombinant baculoviruses were utilized for comparing the expression levels at varying multiplicity of infections (MOI) and time intervals in Spodoptera frugiperda (Sf21) or Trichoplusia ni (Tni) insect cell lines. Targeted insertion of hr1 upstream to CYP-1A2, PKB-A, and Luciferase genes, compared to the non-hr1 sets, led to 3-, 3.5-, and 4.5-fold increase in the resultant protein levels, respectively. Moreover, at equal protein concentration, the corresponding activity and inhibition characteristics of these high expression hr1 sets were comparable to that of the respective non-hr1 sets. Utilization of this modified baculovirus expression construct offers significant advantage of producing recombinant proteins in a cost-effective manner for various biotechnological and therapeutic applications.

HER2+ circulating tumor cells (CTCs): a more sensitive and specific marker for CTCs positivity than total CTCs count in early breast cancer

Abstract #5023

Background: CTCs have been detected using the CellSearch System in early and metastatic breast cancer (BC). However, no studies have been reported for the detection of HER2+ CTCs using the CellSearch System. In this study we aimed to analyze CTCs for HER2 expression in different stages of BC progression from ductal/lobular carcinoma in situ (DCIS/LCIS) to early and metastatic BC. Patients and Methods: 20ml of peripheral blood per woman was analyzed from healthy women, DCIS/LCIS or early BC patients, whereas 7.5ml of blood was analyzed from metastatic BC patients. The presence of CTCs as well as HER2 expression was assessed with the CellSearchSystem (Veridex, USA). After immunomagnetic enrichment with an anti-Epcam-antibody, cells were labeled with anti-cytokeratin (8,18,19), anti-HER2 and anti-CD45 antibodies. CTCs were defined as Cytokeratin-positive/CD45-negative cells, whereas HER2+ CTCs were defined as Cytokeratin-positive/CD45-negative/HER2-positive cells. Results: The presence of CTCs and HER2+ CTCs in healthy women, DCIS/LCIS, early and metastatic BC is depicted in table.&#x2028; &#x2028; Since 1 and 2 CTCs were detected in 7 (14.8%) and 4 (8.5%) of 47 healthy women, respectively, &gt;1CTC or &gt;2CTCs were selected as cutoffs for further analysis. Using the above cutoffs, 7 (18.9%) and 5 (13.5%) of 37 patients with early BC were considered CTC-positive, respectively. Since no HER2+ CTCs were detected in any of the 47 healthy women, a cutoff of ≥1 HER2+ CTCs was chosen. With this cutoff, more women with early BC [11 (29.7%) of 37 women] were considered CTC-positive. Conclusion: HER2+ CTCs seems to be a more sensitive and specific marker for CTCs' positivity than total CTCs counts in early breast cancer. Clinical relevance of the above cutoff for CTCs positivity using HER2+ CTCs detection will be performed in ongoing clinical trials of HER2 positive early breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5023.

The possible significance of Clostridium spp. in blood cultures

The significance of Clostridium spp. in blood cultures was evaluated by two methods. In the first part of the study, a group of 80 patients with Clostridium spp. bacteraemia was compared with a group of 100 patients with Bacillus spp. in blood cultures, making the assumption that Bacillus almost invariably represents contamination (pseudobacteraemia). Significant differences were found between the two groups, suggesting that growth of Clostridium did not represent pseudobacteraemia. Patients with Clostridium bacteraemia were older, had a higher frequency of gastrointestinal disease (especially colorectal tumours), were associated more frequently with polymicrobial bacteraemia, and had a higher mortality rate. In the second part of the study, each of the 80 cases of Clostridium bacteraemia was evaluated individually for clinical relevance by an infectious diseases expert. In two-thirds of the cases, isolates of Clostridium from blood were considered to be of clinical relevance, whereas in one-third of cases, the clinical significance of this finding was doubtful. It was concluded that growth of Clostridium spp. in blood cultures, even in the absence of one of the histotoxic syndromes, is often of clinical significance, and that such findings should be properly evaluated and not ignored.

Comparative analyses of multi-species sequences from targeted genomic regions

The systematic comparison of genomic sequences from different organisms represents a central focus of contemporary genome analysis. Comparative analyses of vertebrate sequences can identify coding and conserved non-coding regions, including regulatory elements, and provide insight into the forces that have rendered modern-day genomes. As a complement to whole-genome sequencing efforts, we are sequencing and comparing targeted genomic regions in multiple, evolutionarily diverse vertebrates. Here we report the generation and analysis of over 12 megabases (Mb) of sequence from 12 species, all derived from the genomic region orthologous to a segment of about 1.8 Mb on human chromosome 7 containing ten genes, including the gene mutated in cystic fibrosis. These sequences show conservation reflecting both functional constraints and the neutral mutational events that shaped this genomic region. In particular, we identify substantial numbers of conserved non-coding segments beyond those previously identified experimentally, most of which are not detectable by pair-wise sequence comparisons alone. Analysis of transposable element insertions highlights the variation in genome dynamics among these species and confirms the placement of rodents as a sister group to the primates.

Simple method for the determination of rosiglitazone in human plasma using a commercially available internal standard

To the best of our knowledge, bioanalytical methods to determine rosiglitazone in human plasma reported in literature use internal standards that are not commercially available. Our purpose was to develop a simple method for the determination of rosiglitazone in plasma employing a commercially available internal standard (IS). After the addition of celecoxib (IS), plasma (0.25 mL) samples were extracted into ethyl acetate. The residue after evaporation of the organic layer was dissolved in 750 microL of mobile phase and 50 microL was injected on to HPLC. The separation was achieved using a Hichrom KR 100, 250 x 4.6 mm C(18) with a mobile phase composition potassium dihydrogen phosphate buffer (0.01 m, pH 6.5):acetonitrile:methanol (40:50:10, v/v/v). The flow-rate of the mobile phase was set at 1 mL/min. The column eluate was monitored by fluorescence detector set at an excitation wavelength of 247 nm and emission wavelength of 367 nm. Linear relationships (r(2) > 0.99) were observed between the peak area ratio rosiglitazone to IS vs rosiglitazone concentrations across the concentration range 5-1000 ng/mL. The intra-run precision (%RSD) and accuracy (%Dev) in the measurement of rosiglitazone were <+/-10.69 and <-12.35%, respectively across the QC levels (50-1000 ng/mL). The extraction efficiency was >80% for both rosiglitazone and IS from human plasma. The lower limit of quantitation of the assay was 5 ng/mL. In summary, the methodology for rosiglitazone measurement in plasma was simple, sensitive and employed a commercially available IS.

HPLC method for the determination of rosiglitazone in human plasma and its application in a clinical pharmacokinetic study

Rosiglitazone (CAS 155141-29-0, Avandia) is a novel insulin sensitizer used in the treatment of type 2 diabetes. A sensitive high performance liquid chromatography (HPLC) method for its determination in human plasma using fluorescence detection (excitation: 247 nm, emission: 367 nm) with a suitable internal standard (I. S.) is described. Ethyl acetate was used as extraction solvent. A mobile phase consisting of phosphate buffer, acetonitrile and methanol was used at a flow rate of 1.0 ml/min on a C18 column. The absolute recovery was > 90% and the lower limit of quantitation was 5 ng/ml. The intra- and inter-day relative standard deviations ranged from 0.58-6.69% and 0.82-6.63%, respectively. The method described is simple, economical, precise and accurate and has been successfully applied in a pharmacokinetic study conducted in healthy human volunteers.

Pediatric laryngoscopes: design and application

Examination of the upper aerodigestive tract for diagnosis and treatment has become more important in pediatric otolaryngology. Techniques of endoscopy have improved, anesthesia is safer, and there are many specialized laryngoscopes designed specifically for the small, sensitive airways of infants and children. Knowledge of the design advantages, specifications, and applications, including the use of telescopes and the operating microscope, will assist in selection of the appropriate laryngoscope for optimum exposure.

Photography of severe laryngeal obstruction

Thirty-five-millimeter photography using rigid rod lens telescopes at direct laryngoscopy is the most versatile and reliable method of laryngeal documentation. Photography of severe laryngeal obstruction, whether in pediatric or adult patients, mandates a method of anesthesia chosen for maximum patient safety, a laryngoscope selected for optimal exposure, confidence in controlling the airway, and a technique that does not jeopardize the safety of the patient.

Anesthesia for pediatric airway endoscopy

Anesthesia for endoscopic assessment and treatment of airway problems in infants and children requires a systematic and thoughtful approach. The anesthesiologist and otolaryngologist should have a sound knowledge of the causes of airway obstruction. The anesthesiologist must be aware of the instrumentation likely to be used and the endoscopist must be well informed about the principles of anesthesia. The choice of technique depends upon the needs for each patient, but in most cases, the safest and most controlled method is a gaseous induction with assisted spontaneous respiration and continued maintenance by the inhalational method, supplemented by topically applied local anesthesia.

Obstructive suprastomal granulation tissue following percutaneous tracheostomy

Percutaneous dilatational tracheostomy is frequently performed as an alternative to traditional surgical open tracheostomy with many reported benefits. Despite its relative safety and widespread acceptance, complications can be associated with the procedure itself or long-term. We present four cases where there was difficulty with decannulation because of exuberant obstructive granulation tissue. In each case, the percutaneous tracheostomy involved the cricoid cartilage.

Recurrent laryngeal nerve injury caused by a laryngeal mask airway

Although there have been few reports of serious complications with the laryngeal mask airway, we record a case of permanent unilateral vocal cord paralysis following the use of a laryngeal mask airway and review the literature describing injuries, not only to the recurrent laryngeal nerves but also to the hypoglossal and lingual nerves.

[Legionellosis in Israel--a view of the situation]

Infection with Legionella remains an important cause of disease and death. We analyzed our laboratory data from 1993 through 1997, augmented by our 20 years of experience. The incidence of Legionella as a cause of pneumonia varied in our study from 5%-9%, with a slight increase during the winter. Isolation of these microorganisms from different water sources was higher during the summer and ranged from 7%-70%. Special laboratory tests are necessary to diagnose the disease and monitor these bacteria in water samples. The serologic method--indirect immunofluorescent assay--for 41 serogroups of Legionella was the main diagnostic method used. Legionella sg. 1 was the most frequent cause of the disease, with an incidence of 52% in 1993, decreasing to 15% in 1997. An increase in the incidence of seropositivity to "other Legionellae" is characteristic for our country. No correlation was found between the incidence of isolation of a specific strain and exposure. However, it is well known that the disease is overtreated but underdiagnosed, which requires reversal. Larger studies of Legionella colonization in water supplies and in air are needed in order to establish the risk of infection. Water sources are presently under-studied, as are respiratory devices in hospitals, or they are not studied at all in Israel, such as in mist machines in supermarkets, in dental clinics, and in ships and airplanes.

Psychosocial stressors among sheltered homeless children: relationship to behavior problems and depressive symptoms

Level of exposure to severe psychosocial stressors was assessed among homeless children in emergency family shelters in an urban locale. The relationship between such exposure and child mental health problems was then investigated, along with the effects of adult family social support. Implications of the findings are discussed.

Thirty-five-millimeter photography using the Kantor-Berci video laryngoscope

The Kantor-Berci model II laryngoscopes employ a centrally located rigid telescope. Although the primary application is for video laryngoscopy, the system can also be used for 35-mm photography during microlaryngeal operations. The fixed, unchangeable field of view and the great depth of focus make this system ideal for photographic documentation during endolaryngeal surgery without interruption of the procedure.

Acute rheumatic fever in southern Saudi Arabia

Forty six attacks of acute rheumatic fever (ARF) in forty patients were diagnosed between November 1987 and August 1995. Thirty four were initial attacks and 12 were recurrences. Arthritis was the commonest feature, 84.8%. Carditis occurred in 65.2% of the group, 67.6% of the initial attacks and 58.3% of the recurrences; however, the frequency of moderate/severe carditis was higher in recurrences, 25% versus 11.8%. Of those with carditis, mitral regurgitation occurred in 93.3%, aortic regurgitation in 16.7% and significant tricuspid regurgitation in 6.7%. Mitral stenosis was not encountered. No mortality occurred during ARF. Chorea, erythema marginatum and subcutaneous nodules were infrequent. These data are similar with those from a previous study which demonstrated the mild nature of ARF in Saudi Arabia, but showed higher frequency of carditis and suggested the frequency of carditis was not significantly higher during recurrences as compared to frequency of moderate/severe carditis.

Indirect laryngeal photography using rigid telescopes

A technique for indirect laryngeal color photography for the office or clinic using rigid rod-lens angled telescopes is outlined. The photographic equipment can be used for documentation at both direct and indirect laryngoscopy except that the latter requires purpose-designed 70 degrees or 90 degrees telescopes. The method, which requires practice and patience, and the equipment are described in detail, and the difficulties and frustrations that are encountered are discussed.

Idiopathic subglottic stenosis: diagnosis and endoscopic laser treatment

The records of 15 patients with idiopathic subglottic stenosis treated at Royal North Shore Hospital, Sydney, between 1980 and 1994 were reviewed. All were female and had similar characteristic clinical and histopathologic features. Endoscopic laser vaporization was the primary treatment in 12 patients and was successful in maintaining the airway of 8 of these 12; this outcome indicates that the disease can be managed, at least initially, by endoscopic laser treatment in most cases.

Airway management in acute infectious croup syndromes

The article presents the author's experience with airway management of 500 children with acute infectious croup and epiglottitis over a 7-year period in a teaching hospital setup. A policy of early elective protective intubation under controlled condition for children with severe croup and epiglottitis, in a multidisciplinary intensive care setting resulted in a satisfactory outcome. Recent developments in the field are discussed; these include non-invasive monitoring, medical treatment options for viral croup with parenteral high dose dexamethasone and nebulized adrenaline, newer broad-spectrum antimicrobials for drug-resistant bacterial infectious and an effective vaccine against Hemophilus influenzae type b. These hold the promise of reducing morbidity and mortality from acute infectious croup syndromes even in situations with limited surgical and monitoring facilities.

Renal agenesis and ureteropelvic junction obstruction in an infant with Turner syndrome

An infant who had Turner syndrome with left renal agenesis and right hydronephrosis due to functional ureteropelvic junction obstruction is reported. The importance of routine imaging for early identification of potentially serious renal anomalies in patients being evaluated for short stature and possible Turner syndrome is emphasized.