Fibril specific, conformation dependent antibodies recognize a generic epitope common to amyloid fibrils and fibrillar oligomers that is absent in prefibrillar oligomers

BACKGROUND

Amyloid-related degenerative diseases are associated with the accumulation of misfolded proteins as amyloid fibrils in tissue. In Alzheimer disease (AD), amyloid accumulates in several distinct types of insoluble plaque deposits, intracellular Abeta and as soluble oligomers and the relationships between these deposits and their pathological significance remains unclear. Conformation dependent antibodies have been reported that specifically recognize distinct assembly states of amyloids, including prefibrillar oligomers and fibrils.

RESULTS

We immunized rabbits with a morphologically homogeneous population of Abeta42 fibrils. The resulting immune serum (OC) specifically recognizes fibrils, but not random coil monomer or prefibrillar oligomers, indicating fibrils display a distinct conformation dependent epitope that is absent in prefibrillar oligomers. The fibril epitope is also displayed by fibrils of other types of amyloids, indicating that the epitope is a generic feature of the polypeptide backbone. The fibril specific antibody also recognizes 100,000 x G soluble fibrillar oligomers ranging in size from dimer to greater than 250 kDa on western blots. The fibrillar oligomers recognized by OC are immunologically distinct from prefibrillar oligomers recognized by A11, even though their sizes overlap broadly, indicating that size is not a reliable indicator of oligomer conformation. The immune response to prefibrillar oligomers and fibrils is not sequence specific and antisera of the same specificity are produced in response to immunization with islet amyloid polypeptide prefibrillar oligomer mimics and fibrils. The fibril specific antibodies stain all types of amyloid deposits in human AD brain. Diffuse amyloid deposits stain intensely with anti-fibril antibody although they are thioflavin S negative, suggesting that they are indeed fibrillar in conformation. OC also stains islet amyloid deposits in transgenic mouse models of type II diabetes, demonstrating its generic specificity for amyloid fibrils.

CONCLUSION

Since the fibril specific antibodies are conformation dependent, sequence-independent, and recognize epitopes that are distinct from those present in prefibrillar oligomers, they may have broad utility for detecting and characterizing the accumulation of amyloid fibrils and fibrillar type oligomers in degenerative diseases.

The roles of tissue engineering and vascularisation in the development of micro-vascular networks: a review

The construction of tissue-engineered devices for medical applications is now possible in vitro using cell culture and bioreactors. Although methods of incorporating them back into the host are available, current constructs depend purely on diffusion which limits their potential. The absence of a vascular network capable of distributing oxygen and other nutrients within the tissue-engineered device is a major limiting factor in creating vascularised artificial tissues. Though bio-hybrid prostheses such as vascular bypass grafts and skin substitutes have already been developed and are being used clinically, the absence of a capillary bed linking the two systems remains the missing link. In this review, the different approaches currently being or that have been applied to vascularise tissues are identified and discussed.

Assessment of beta-cell function in humans, simultaneously with insulin sensitivity and hepatic extraction, from intravenous and oral glucose tests

Assessment of insulin secretion in humans under physiological conditions has been a challenge because of its complex interplay with insulin action and hepatic insulin extraction. The possibility of simultaneously assessing beta-cell function, insulin sensitivity, and hepatic insulin extraction under physiological conditions using a simple protocol is appealing, since it has the potential to provide novel insights regarding the regulation of fasting and postprandial glucose metabolism in diabetic and nondiabetic humans. In this Perspective, we review data indicating that an oral glucose tolerance test (OGTT) or a meal test is able to accomplish this goal when interpreted with the oral beta-cell minimal model. We begin by using the well-established intravenous minimal model to highlight how the oral minimal model was developed and how the oral assessment parallels that of an intravenous glucose tolerance test (IVGTT). We also point out the unique aspects of both approaches in relation to their ability to assess different aspects of the beta-cell secretory cascade. We review the ability of the oral model to concurrently measure insulin sensitivity and hepatic insulin extraction, thereby enabling it to quantitatively portray the complex relationship among beta-cell function, hepatic insulin extraction, and insulin action. In addition, data from 204 individuals (54 young and 159 elderly) who underwent both IVGTT and meal tolerance tests are used to illustrate how these different approaches provide complementary but differing insights regarding the regulation of beta-cell function in humans.

Cardiac troponin I is a sensitive, specific biomarker of cardiac injury in laboratory animals

This study directly demonstrates that cardiac troponin I (cTnI) is a sensitive, specific, and persistent biomarker in laboratory animals. Histopathological and pathophysiological cardiac changes in dogs, rats and mice correlated with increased serum cTnI with various cardiac inotropic agents, and cardiotoxic drugs and with cardiac arrhythmias, tachycardia, cardiac effusion with dyspnoea, and ageing. A comparison of six immunoassays for cTnI and cardiac troponin T (cTnT) to detect and monitor cardiac injury in a rodent model indicated that enzyme-linked immunosorbent (Life Diagnostics Inc and TriChem Resources Inc, West Chester, Philadelphia, USA) and Immulite (Diagnostic Products Corporation, Llanberis, UK) assays had low sensitivity and less than 1% of the dynamic range of Centaur (Bayer Healthcare Diagnostics, Newbury, UK) cTnI and Elecsys (Roche Diagnostics, Basel, Switzerland) and M8 (Bioveris Europe, Whitney, UK) cTnT assays. In dogs, however, the Immulite assay was effective and correlated with the Centaur. Serum concentrations were highly correlated but 10-fold lower for cTnT compared with cTnI with cardiac injury. Centaur assay also detected cTnI in myocardium from marmosets, swine, cattle, and guineapigs, indicating it to be candidate cardiac biomarker for these species as well. Purified rat cTnI was 50% more reactive than purified human cTnI in the Centaur assay. In the rat, an age- and gender-dependent variation in serum cTnI was found. Male rats aged six and eight months had a 10-fold greater serum cTnI than age-matched females and three-month-old rats. These increases correlated with minimal histopathological change. Isoproterenol-induced serum cTnI increased up to 760-fold the minimal detectable concentration of 0.07 μg/L, within 4–6 h and decreased with a half-life of 6 h, with an expected return to baseline of 60 h. Severity of histopathological change correlated with serum cTnI during the ongoing injury.

The role of the dynamics of focal adhesion kinase in the mechanotaxis of endothelial cells

The migration of vascular endothelial cells (ECs) is critical in vascular remodeling. We showed that fluid shear stress enhanced EC migration in flow direction and called this "mechanotaxis." To visualize the molecular dynamics of focal adhesion kinase (FAK) at focal adhesions (FAs), FAK tagged with green fluorescence protein (GFP) was expressed in ECs. Within 10 min of shear stress application, lamellipodial protrusion was induced at cell periphery in the flow direction, with the recruitment of FAK at FAs. ECs under flow migrated with polarized formation of new FAs in flow direction, and these newly formed FAs subsequently disassembled after the rear of the cell moved over them. The cells migrating under flow had a decreased number of FAs. In contrast to shear stress, serum did not significantly affect the speed of cell migration. Serum induced lamellipodia and FAK recruitment at FAs without directional preference. FAK(Y397) phosphorylation colocalized with GFP-FAK at FAs in both shear stress and serum experiments. The total level of FAK(Y397) phosphorylation after shear stress was lower than that after serum treatment, suggesting that the polarized change at cell periphery rather than the total level of FAK(Y397) phosphorylation is important for directional migration. Our results demonstrate the dynamics of FAK at FAs during the directional migration of EC in response to mechanical force, and suggest that mechanotaxis is an important mechanism controlling EC migration.

How Do head and neck cancer patients prioritize treatment outcomes before initiating treatment?

PURPOSE

To determine, pretreatment, how head and neck cancer (HNC) patients prioritize potential treatment effects in relationship to each other and to survival and to ascertain whether patients' preferences are related to demographic or disease characteristics, performance status, or quality of life (QOL).

PATIENTS AND METHODS

One hundred thirty-one patients were assessed pretreatment using standardized measures of QOL (Functional Assessment of Cancer Therapy-Head and Neck) and performance (Performance Status Scale for Head and Neck Cancer). Patients were also asked to rank a series of 12 potential HNC treatment effects.

RESULTS

Being cured was ranked top priority by 75% of patients; another 18% ranked it second or third. Living as long as possible and having no pain were placed in the top three by 56% and 35% of patients, respectively. Items that were ranked in the top three by 10% to 24% of patients included those related to energy, swallowing, voice, and appearance. Items related to chewing, being understood, tasting, and dry mouth were placed in the top three by less than 10% of patients. Excluding the top three rankings, there was considerable variability in ratings. Rankings were generally unrelated to patient or disease characteristics, with the exception that cure and living were of slightly lower priority and pain of higher priority to older patients compared with younger patients.

CONCLUSION

The data suggest that, at least pretreatment, survival is of primary importance to patients, supporting the development of aggressive treatment strategies. In addition, results highlight individual variability and warn against making assumptions about patients' attitudes vis-à-vis potential outcomes. Whether patients' priorities will change as they experience late effects is currently under investigation.

Tissue engineered neocartilage using plasma derived polymer substrates and chondrocytes

This study demonstrates that fibrin monomers can be polymerized into moldable gels and used for the encapsulation of isolated chondrocytes. This biologically derived scaffold will maintain three-dimensional spatial support, allowing new tissue development in a subcutaneous space. Chondrocytes isolated from the glenohumeral and humeroradioulnar joints of a calf were combined with cyroprecipitate and polymerized with bovine thrombin to create a fibrin glue gel with a final cell density of 12.5 x 10(6) cells/ml. The polymer-chondrocyte constructs were implanted subcutaneously in 12 nude mice and incubated for 6 and 12 weeks in vivo. Histologic and biochemical analysis including deoxyribonucleic acid (DNA) and glycosaminoglycan quantitation confirmed the presence of actively proliferating chondrocytes with production of a well-formed cartilaginous matrix in the transplanted samples. Control specimens from 12 implantation sites consisting of chondrocytes alone or fibrin glue substrates did not demonstrate any gross or histologic evidence of neocartilage formation. Moldable autogenous fibrin glue polymer systems have a potential to serve as alternatives to current proprietary polymer systems used for tissue engineering cartilage as well as autogenous grafts and alloplastic materials used for facial skeletal and soft-tissue augmentation.

The UK colorectal cancer screening pilot: results of the second round of screening in England

An evaluation of the second round of faecal occult blood (FOB) screening in the English site of the UK Colorectal Cancer Screening Pilot (comprising the Bowel Cancer Screening Pilot based in Rugby, general practices in four Primary Care Trusts, and their associated hospitals) was carried out. A total of 127 746 men and women aged 50–69 and registered in participating general practices were invited to participate. In all, 15.9% were new invitees not included in the previous round. A total of 52.1% of invitees returned a screening kit. Uptake varied with gender, age, and level of deprivation; was lower than in the first round (51.9 vs 58.5% P<0.0001), but was high (81.1%) in those who had participated in the first round with a negative result. Test positivity was 1.77%, significantly higher than in the first round, and the detection rate of neoplasia similar (5.67 per 1000), resulting in a lower positive predictive value. The sensitivity of FOBt in the first round was estimated as 57.7–64.4%. There was a significant impact on workload, particularly on endoscopy services. The cancer detection rate (0.94 per 1000) was lower than in the first round. Effort will be required to minimise inequalities in uptake, and to ensure adequate capacity of endoscopy services.

Pulsatile insulin secretion: detection, regulation, and role in diabetes

Insulin concentrations oscillate at a periodicity of 5-15 min per oscillation. These oscillations are due to coordinate insulin secretory bursts, from millions of islets. The generation of common secretory bursts requires strong within-islet and within-pancreas coordination to synchronize the secretory activity from the beta-cell population. The overall contribution of this pulsatile mechanism dominates and accounts for the majority of insulin release. This review discusses the methods involved in the detection and quantification of periodicities and individual secretory bursts. The mechanism by which overall insulin secretion is regulated through changes in the pulsatile component is discussed for nerves, metabolites, hormones, and drugs. The impaired pulsatile secretion of insulin in type 2 diabetes has resulted in much focus on the impact of the insulin delivery pattern on insulin action, and improved action from oscillatory insulin exposure is demonstrated on liver, muscle, and adipose tissues. Therefore, not only is the dominant regulation of insulin through changes in secretory burst mass and amplitude, but the changes may affect insulin action. Finally, the role of impaired pulsatile release in early type 2 diabetes suggests a predictive value of studies on insulin pulsatility in the development of this disease.

Hyperbaric oxygen as adjuvant therapy in the management of necrotizing fasciitis

BACKGROUND

Necrotizing fasciitis (NF) is an uncommon but serious infection of fascia and skin associated with considerable morbidity and mortality. One modality proposed for improving the outcome of this condition is hyperbaric oxygen (HBO) therapy. This is a form of medical treatment that involves intermittent inhalation of 100% oxygen under pressures exceeding the atmosphere. The aim of this article is to review current practice and evidence for the use of HBO as adjunctive therapy in the management of NF.

METHODS

A survey of published English literature through searches of Medline and PubMed was carried out using the following key words: "necrotizing fasciitis," "Fournier's gangrene," "necrotizing soft tissue infections," "hyperbaric oxygen therapy," "and hyperbaric oxygen chambers."

RESULTS

The results of studies on the use of HBO therapy in NF are inconsistent. Some studies have demonstrated that HBO can improve patient survival and decrease the number of debridements required to achieve wound control, whereas others have failed to show any beneficial effect.

CONCLUSIONS

Encouraging results have been achieved with the addition of HBO therapy to standard treatment regimes, thus justifying further research in this field. More robust evidence by way of a prospective randomized trial is necessary before widespread and routine use of HBO in the management of NF can be recommended.

Systematic review of patient factors affecting adipose stem cell viability and function: implications for regenerative therapy

BACKGROUND

The applications for fat grafting have increased recently, within both regenerative and reconstructive surgery. Although fat harvesting, processing and injection techniques have been extensively studied and standardised, this has not had a big impact on the variability of outcome following fat grafting. This suggests a possible larger role of patient characteristics on adipocyte and adipose-derived stem cell (ADSC) viability and function. This systematic review aims to collate current evidence on the effect of patient factors on adipocyte and ADSC behaviour.

METHODS

A systematic literature review was performed using MEDLINE, Cochrane Library and EMBASE. It includes outcomes observed in in vitro analyses, in vivo animal studies and clinical studies. Data from basic science work have been included in the discussion to enhance our understanding of the mechanism behind ADSC behaviour.

RESULTS

A total of 41 papers were included in this review. Accumulating evidence indicates decreased proliferation and differentiation potential of ADSCs with increasing age, body mass index, diabetes mellitus and exposure to radiotherapy and Tamoxifen, although this was not uniformly seen across all studies. Gender, donor site preference, HIV status and chemotherapy did not show a significant influence on fat retention. Circulating oestrogen levels have been shown to support both adipocyte function and graft viability. Evidence so far suggests no significant impact of total cholesterol, hypertension, renal disease, physical exercise and peripheral vascular disease on ADSC yield.

CONCLUSIONS

A more uniform comparison of all factors highlighted in this review, with the application of a combination of tests for each outcome measure, is essential to fully understand factors that affect adipocyte and ADSC viability, as well as functionality. As these patient factors interact, future studies looking at adipocyte viability need to take them into consideration for conclusions to be meaningful. This would provide crucial information for surgeons when deciding appropriate volumes of lipoaspirate to inject, improve patient selection, and counsel patient expectations with regards to outcomes and likelihood for repeat procedures. An improved understanding will also assist in identification of patient groups that would benefit from graft enrichment and cryopreservation techniques.

Injectable cartilage using polyethylene oxide polymer substrates

This study demonstrates that polyethylene oxide gels, which are biocompatible and biodegradable synthetic polymers, can be utilized for the encapsulation of isolated chondrocytes and maintenance of three-dimensional spatial support for new tissue development. Chondrocytes isolated from the glenohumeral and humeroradioulnar joints of a calf were added to a 20% polyethylene oxide solution in Ham's F-12 medium to generate a final cellular density of 10 x 10(6)/mL. The polymer-chondrocyte constructs were injected through a 22-gauge needle in 500-microliters aliquots subcutaneously in 12 nude mice and incubated for 6 and 12 weeks in vivo. Histologic and biochemical analyses including deoxyribonucleic acid and glycosaminoglycan quantitative analyses confirmed the presence of actively proliferating chondrocytes with production of a well-formed cartilaginous matrix in the transplanted samples. Control specimens from eight implantation sites consisting of chondrocytes alone or polyethylene oxide substrates did not demonstrate any gross or histologic evidence of neocartilage formation. These findings demonstrate the potential use of an injectable and moldable polymer substrate that can support cell proliferation and matrix synthesis after subcutaneous transplantation for neocartilage generation. The use of functional biologic tissue substitutes may serve as an alternative solution to current methods of augmentation or reconstruction of structural craniofacial contour deformities.

The incidence of craniocervical bony anomalies in the adult Chiari malformation

Detailed linear, angular and surface area measurements were undertaken on the lateral skull radiographs of 32 patients with proven idiopathic adult Chiari type 1 malformation. Basal angles were larger, the clivus was shorter and Klaus' index was reduced in patients compared to normal controls. The size of the posterior fossa was smaller in patients than in controls. By discriminant analysis of the skull X-ray data it was possible to identify correctly two thirds of patients as belonging to the patient group. The findings indicate that craniocervical bony anomalies in the adult Chiari malformation are commoner than was previously realised, and they support the view that tonsillar herniation in these patients results from bony occipital dysplasia.

Physiological cost index of walking for normal children and its use as an indicator of physical handicap

Seventy-two normal children aged between three and 12 years were assessed to establish their walking function. Speed of walking and heart rate were monitored continuously, both barefoot and in shoes, over eight consecutive lengths of a 25m walkway. Since heart rate is affected by speed, the physiological cost index (PCI)--which combines the two parameters--was calculated for each child, both barefoot and in shoes. Speed tends to increase and walking heart rate to decrease with age. However, resting heart rate also decreases with age, so the PCI has the same range for all ages. The mean PCI in shoes was 0.4 and barefoot was 0.38. The PCI for children with pathological gait is appreciably greater than that for normal children, so the PCI is a valuable quantitative indicator of the level of handicap.

The regenerative role of adipose-derived stem cells (ADSC) in plastic and reconstructive surgery

The potential use of stem cell-based therapies for the repair and regeneration of various tissues and organs offers a paradigm shift in plastic and reconstructive surgery. The use of either embryonic stem cells (ESC) or induced pluripotent stem cells (iPSC) in clinical situations is limited because of regulations and ethical considerations even though these cells are theoretically highly beneficial. Adult mesenchymal stem cells appear to be an ideal stem cell population for practical regenerative medicine. Among these cells, adipose-derived stem cells (ADSC) have the potential to differentiate the mesenchymal, ectodermal and endodermal lineages and are easy to harvest. Additionally, adipose tissue yields a high number of ADSC per volume of tissue. Based on this background knowledge, the purpose of this review is to summarise and describe the proliferation and differentiation capacities of ADSC together with current preclinical data regarding the use of ADSC as regenerative tools in plastic and reconstructive surgery.

Historical Article: Hirudo medicinalis : ancient origins of, and trends in the use of medicinal leeches throughout history

Blood letting and the therapeutic use of Hirudo medicinalis date back to ancient Egypt and the beginning of civilisation. Their popularity has varied over the years, reaching such a peak in Europe between 1825 and 1850 that supplies were exhausted. Towards the end of the century they fell out of favour and, during this period, the leech, once used by the physicians of emperors and influential academic surgeons, became associated with lay therapists and quackery. Leeches have enjoyed a renaissance in reconstructive microsurgery during the last 15 years, having been used by maxillofacial [Br. J. Oral Maxillofac. Surg 41 (2003) 44] and other reconstructive surgeons to aid salvage of compromised microvascular free tissue transfers [Laryngoscope 108 (1998) 1129; Br. J. Plast. Surg. 34 (1984) 358], replanted digits [Int. J. Microsurg. 3 (1981) 265], ears [Ann. Plast. Surg. 43 (1999) 427], lips [Plast. Reconstr. Surg. 102 (1998) 358; J. Reconstr. Microsurg. 9 (1993) 327] and nasal tips [Br. J. Oral Maxillofac. Surg. 36 (1998) 462]. Peer-reviewed evidence suggests that the survival of compromised, venous-congested tissues is improved by early application of a leech [J. Reconstr. Microsurg. 12 (1996) 165; Arch. Otolaryngol. Head Neck Surg. 114 (1988) 1395; Br. J. Plast. Surg. 45 (1992) 235]. Leeches have also recently been used to treat a wide range of conditions, including periorbital haematomas [Br. J. Ophthalmol. 75 (1991) 755], severe macroglossia [Otolaryngol. Head Neck Surg. 125 (2001) 649; J. Laryngol. Otol. 109 (1995) 442] and purpura fulminans [Ann. Plast. Surg. 35 (1995) 300]. The first medicinal leech farm, Biopharm, was set up in Swansea in 1981 by Dr Roy Sawyer, and now supplies leeches to hospitals all over the world. In this paper, we summarise the history of treatment with Hirudo medicinalis from its origin to the present day, and take a brief look at the possible future of the annelid.

Heart rates and abdominal temperatures of free-ranging South Georgian shags, Phalacrocorax georgianus

The South Georgian shag (Phalacrocorax georgianus) shows a remarkable diving ability comparable to that of penguins, yet nothing is known of the physiology of these birds. In this study, heart rates and abdominal temperatures were recorded continuously in four free-ranging South Georgian shags using an implanted data-logger. A time&shy;depth recorder was also attached to the back of the implanted birds to record their diving behaviour. The diving behaviour of the birds was essentially similar to that reported in other studies, with maximum dive durations for individual birds ranging between 140 and 287 s, and maximum depths between 35 and 101 m. The birds, while at the nest, had a heart rate of 104.0&plusmn;13.1 beats min-1 (mean &plusmn; s.e.m.) and an abdominal temperature of 39.1&plusmn;0.2 &deg;C. During flights of 221&plusmn;29 s, heart rate and abdominal temperature rose to 309.5&plusmn;18.0 beats min-1 and 40.1&plusmn;0.3 &deg;C, respectively. The mean heart rate during diving, at 103.7&plusmn;13.7 beats min-1, was not significantly different from the resting values, but the minimum heart rate during a dive was significantly lower at 64.8&plusmn;5.8 beats min-1. The minimum heart rate during a dive was negatively correlated with both dive duration and dive depth. Abdominal temperature fell progressively during a diving bout, with a mean temperature at the end of a bout of 35.1&plusmn;1.7 &deg;C. The minimum heart rate during diving is at a sub-resting level, which suggests that the South Georgian shag responds to submersion with the 'classic' dive response of bradycardia and the associated peripheral vasoconstriction and utilisation of anaerobic metabolism. However, the reduction in abdominal temperature may reflect a reduction in the overall metabolic rate of the animal such that the bird can remain aerobic while submerged.

The relation of preoperative coagulation findings to diagnosis, blood usage, and survival in adult liver transplantation

A group of 70 adults with end-stage liver disease received 87 homologous liver transplants from 7/11/81 and 7/11/83. The recipients fell into the following diagnostic categories: postnecrotic cirrhosis (PNC) in 22, primary biliary cirrhosis (PBC) in 18, cancer or neoplasia (CA) in 11, sclerosing cholangitis (SC) in 8 and miscellaneous (MISC) in 11. Survival for six months or longer was 46%: survival by group was PBC = 67%, CA = 55%, PNC = 45%, SC = 25%, and MISC = 18%. Preoperative coagulation profiles were evaluated on 64 of the 70 first transplant patients by assigning a score derived from one point per abnormality in each of 8 tests. Mean coagulation abnormality scores (CAS) were strikingly elevated in the PNC and MISC groups. Mean intraoperative blood product usage was 43 units of RBCs, 40 units of fresh frozen plasma (FFP), 21 units of platelets, and 9 bags of cryoprecipitate. Direct correlations were found between CAS and RBC usage (+0.454, P = less than .001), CAS, and survival of 6 months or longer (-0.281, P = less than .02), and RBC usage and survival (-0.408, P = less than .001). These findings indicate that the degree of coagulation abnormality and the type of liver disease may be predictive of intraoperative blood usage and survival in liver transplantation in adults.

Adipose-derived stem cells for clinical applications: a review

The use of stem cells derived from adipose tissue as an autologous and self-replenishing source for a variety of differentiated cell phenotypes, provides a great deal of promise for reconstructive surgery. In this article, we review available literature encompassing methods of extraction of pluripotent adipose stem cells (ASCs) from lipoaspirate locations, their storage, options for culture, growth and differentiation, cryopreservation and its effect on stem cell survival and proliferation, and new technologies involving biomaterials and scaffolds. We will conclude by assessing potential avenues for developing this incredibly promising field.

Accumulation and metabolism of drugs and CYP probe substrates in zebrafish larvae

This study examined the accumulation and metabolism of a number of drugs and commonly used probes for human cytochrome P450s (CYPs) in zebrafish larvae under conditions relevant to pharmacological and toxicological assays. Studies with cisapride, chlorpromazine, verapamil, testosterone, and dextromethorphan showed that the zebrafish larvae catalyze a range of phase 1 (oxidation, N-demethylation, O-de-ethylation, and N-dealkylation) and phase 2 (sulfation and glucuronidation) reactions. Both similarities and differences in the metabolic pathways were observed in zebrafish larvae when compared to mammals. Metabolism of phenacetin to paracetamol and dextromethorphan to dextrorphan (metabolic reactions catalyzed by CYP 1A2 and 2D6 in humans respectively) were observed in the zebrafish larvae. In addition the zebrafish larvae 7 days post fertilization (7 d.p.f.) hydroxylated diclofenac, bupropion, tacrine, and testosterone. Although metabolites of several compounds were detected in zebrafish larvae, in the instances where the metabolite amounts were quantified, the amount of any specific metabolite formed was low, accounting for only a small percentage of the amount of parent compound added. Furthermore, when the concentrations of metabolite present in the zebrafish larvae were compared with the measured level of parent compound, the metabolite concentrations were always much lower than that of parent compound. Overall, for the compounds used in the current study it is unlikely that the quantified metabolites would significantly contribute to the outcome of safety pharmacology or toxicology studies conducted in zebrafish larvae under the paradigms typically used for such investigations.

Cervical spine injuries in patients with facial fractures: a 1-year prospective study

A total of 582 consecutive patients with facial fractures were investigated prospectively for evidence of a concomitant cervical spine injury. Of them, 1.04% (6) were found to have a cervical spine injury, all having occurred in road traffic accidents. Only two of the injuries were diagnosable on standard, three-view, plain cervical spine radiographs. Four were diagnosable from computerized tomography scan, while the remaining two required stress views under radiographic screening for definitive diagnosis.

Systematic Review of the Use of 3-Dimensional Printing in Surgical Teaching and Assessment

OBJECTIVE

The use of 3-dimensional (3D) printing in medicine has rapidly expanded in recent years as the technology has developed. The potential uses of 3D printing are manifold. This article provides a systematic review of the uses of 3D printing within surgical training and assessment.

METHODS

A structured literature search of the major literature databases was performed in adherence to PRISMA guidelines. Articles that met predefined inclusion and exclusion criteria were appraised with respect to the key objectives of the review and sources of bias were analysed.

RESULTS

Overall, 49 studies were identified for inclusion in the qualitative analysis. Heterogeneity in study design and outcome measures used prohibited meaningful meta-analysis. 3D printing has been used in surgical training across a broad range of specialities but most commonly in neurosurgery and otorhinolaryngology. Both objective and subjective outcome measures have been studied, demonstrating the usage of 3D printed models in training and education. 3D printing has also been used in anatomical education and preoperative planning, demonstrating improved outcomes when compared to traditional educational methods and improved patient outcomes, respectively.

CONCLUSIONS

3D printing technology has a broad range of potential applications within surgical education and training. Although the field is still in its relative infancy, several studies have already demonstrated its usage both instead of and in addition to traditional educational methods.

Natural history of indeterminate pigmented choroidal tumors

PURPOSE

The purpose of this study is to delineate the natural history of indeterminate pigmented choroidal lesions and identify parameters from the initial visit that correlate with lesion enlargement.

METHODS

The authors retrospectively reviewed the records of all patients with indeterminate pigmented choroidal lesions seen in consultation at the Ocular Oncology Unit at the University of California, San Francisco, after 1975. Clinical examination, fundus photography, fluorescein angiography, and ultrasound data were examined. Investigators masked to outcome coded sequential parameters of each of these modalities. Data were analyzed using both univariate and multivariate censored data techniques.

RESULTS

Of 293 lesions, 98 grew. The 5-year actuarial rate of growth was 36%. Greater tumor thickness, presence of symptoms, orange pigment, internal quiet zone on B-scan, and hot spots on fluorescein angiography all were significant predictors of tumor enlargement (relative risk of detectable tumor growth, > 1.8). Risk scores were calculated, and subsets with higher probability of future growth were identified. In five of the patients with growing lesions, metastatic disease developed after a median posttreatment follow-up period of 51 months.

CONCLUSION

Most small indeterminate pigmented lesions can be followed safely by serial observation and ancillary testing. The authors identified models based on data from the initial visit that can be used as an adjunct to planning tumor management.

Hirudo Medicinalis and the plastic surgeon

Medicinal leech therapy is an ancient craft that dates back to ancient Egypt and the beginnings of civilisation. The popularity of Hirudo Medicinalis has varied throughout history, reaching such a peak in Europe in the early 19th century that supplies were exhausted. During the latter half of the 19th century, their use fell out of favour, as they did not fit in with the emerging concepts of modern medicine. Leeches have enjoyed a renaissance in the world of reconstructive microsurgery during recent years, and their first reported use in alleviating venous engorgement following flap surgery was reported in this journal [M Derganc, F Zdravic, Venous congestion of flaps treated by application of leeches, Br J Plast Surg 13 (1960) 187]. Contemporary plastic and reconstructive surgeons in units throughout the United Kingdom and Ireland continue to use leeches to aid salvage of failing flaps. We carried out a survey of all 62 plastic surgery units in the United Kingdom and the Republic of Ireland to assess the current extent of use, and to investigate current practice. We have shown that the majority of plastic surgery units in the UK and Ireland use leeches post-operatively and that the average number of patients requiring leech therapy was 10 cases per unit per year. Almost all units use antibiotic prophylaxis, but the type of antibiotic and combination used is variable. We outline current practice and suggest a protocol for the use of leeches. Whilst the use of leeches is widespread, the plastic surgery community has progressed little in defining indications for their use or in achieving an accepted protocol for their application in units throughout the UK and Ireland.