Effectiveness of different treatments for odontogenic keratocyst: a network meta-analysis

Odontogenic keratocysts (OKC) are benign but aggressive lesions. As there is a lack of well randomized clinical studies assessing the effectiveness of the different treatment options for OKC, a network meta-analysis (NMA) was performed to identify the best treatment option with the lowest recurrence rate. An electronic search was performed following the PRISMA guidelines to identify all clinical studies comparing treatment options against enucleation alone. The outcome variable was recurrence. The predictor variables were treatments. The eight included treatments were: enucleation with peripheral ostectomy/curettage (E + PO/curettage); enucleation with cryotherapy (E + CRYO); enucleation with/without PO followed by modified Carnoy's solution (E ± PO+MCS); enucleation with PO and with topical 5-fluorouracil (E + PO+5FU); enucleation with/without PO followed by original Carnoy's solution (E ± PO+CS); marsupialization alone (MARS); marsupialization followed by secondary enucleation with/without PO (MARS+2°E ± PO); and resection. The odds ratio was used to estimate the recurrence rate. A frequentist NMA was performed using Stata software. A total of 2989 patients in 40 studies were included. Both direct pairwise meta-analysis and NMA showed that E + 5FU+PO was significantly superior to E ± PO+MCS. However, no statistically significant difference was found between E ± PO+CS vs E + 5FU+PO, E ± PO+MCS, and resection, respectively (all very low quality evidence). The three most effective treatments in reducing the recurrence rate were E + PO+ 5FU (98.1%; very low quality evidence), resection (83.5%; very low quality evidence), and E ± PO+CS (63.8%; moderate quality evidence). The findings from this study suggest that CS remains the most effective fixative agent after enucleation and PO until proven otherwise. Additionally, 5FU appears to be an effective method with promising results that needs further research. Finally, the efficacy of MCS remains controversial; further in vivo and in vitro studies are required to determine new protocols. As this NMA included retrospective studies, the results should be interpreted with great caution (level of evidence: type III).

Regulation of bile acid metabolism in biliary atresia: reduction of FGF19 by Kasai portoenterostomy and possible relation to early outcome

BACKGROUND

Fibroblast growth factor 19 (FGF19) is produced in the small intestine and is involved in suppression of hepatic bile acid (BA) synthesis. FGF19 is also expressed in the liver and serum levels are elevated in adults with cholestatic liver disease. This may reflect a rescue mechanism to dampen liver injury caused by increased intrahepatic BAs.

OBJECTIVES

To examine circulating FGF19 at early stages of biliary atresia and at short-term follow-up post-Kasai portoenterostomy (KPE) in relation to noncholestatic infants. The relationship between FGF19, BAs and markers for BA synthesis and hepatic gene expression of factors involved in BA metabolism were also evaluated.

METHODS

Liver tissue, portal and peripheral blood samples were obtained from fifteen patients at KPE; additional blood was collected 4-6 months after surgery. Two control groups were included; to examine possible changes related to surgery and to compare FGF19 in biliary atresia to noncholestatic infants.

RESULTS

Circulating FGF19 levels correlated to its hepatic gene expression at time of KPE in biliary atresia and levels were elevated compared to noncholestatic infants. At follow-up, FGF19 levels were markedly reduced, and the decline coincided with reductions in bilirubin and conjugated chenodeoxycholic acid and with increased levels of the BA synthesis marker C4.

CONCLUSION

Elevated circulating FGF19 in biliary atresia is of hepatic origin and reduced following KPE. Changes in serum FGF19 may reflect the level of restoration of the enterohepatic circulation, and this warrants further long-term studies on the role of FGF19 in the cholestatic liver.

Abstract P1-15-02: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Schwab R, Clark A, Yau C, Wolf D, Chien AJ, Majure M, Ewing C, Wallace A, Roesch E, Helsten T, Forero A, Stringer-Reasor E, Vaklavas C, Nanda R, Jaskowiak N, Boughey J, Haddad T, Han H, Lee C, Albain K, Isaacs C, Elias A, Ellis E, Shah P, Lang J, Lu J, Tripathy D, Kemmer K, Yee D, Haley B, Korde L, Edmiston K, Northfelt D, Viscusi R, Khan Q, I-SPY 2 Consortium, Symmans WF, Perlmutter J, Hylton N, Rugo H, Melisko M, Wilson A, Singhrao R, Asare S, van't Veer L, DeMichele A, Berry D, Esserman L. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-15-02.

Abstract AP30: PHASE IB/II WITH EXPANSION OF PATIENTS AT THE MTD STUDY OF OLAPARIB PLUS WEEKLY (METRONOMIC) CARBOPLATIN AND PACLITAXEL IN RELAPSED OVARIAN CANCER PATIENTS

BACKGROUND: We established the olaparib tablet maximum tolerated dose (MTD) at 150 mg bid, dose limiting toxicities (DLT's) and response to therapy or carboplatin, paclitaxel and olaparib tablet given simultaneously, reported at ASCO 2014. This abstract will include data from both the phase 1b and the phase 2 expansion.

METHODS: A total of 54 subjects were evaluated in this trial, 14 in phase 1b and 40 in phase 2. Eligibility required measurable disease, adequate organ function and ECOG performance status of ~ 2. Subjects had to have failed first line platinum containing chemotherapy. BRCA testing was conducted as available. Subjects received the metronomic therapy of paclitaxel 60mg/m2 IV and carboplatin AUC 2 IV weekly, 3 weeks out of 4, and olaparib tablets at 150 mg bid administered orally for 3 consecutive days (D1-D3) every week for each cycle. Subjects were assessed for toxicity and response according to the protocol. Subjects that reached a confirmed complete remission were transitioned to olaparib tablets only, 300 mg bid until disease progression.

RESULTS: Median age was 58 and median number of prior regimens was 4. There have been no deaths due to the study regimen. One patient had grade 4 neutropenia and an allergic reaction to carboplatin. The common grade 3/4 toxicities were caused by the chemotherapy (neutropenia. anemia and thrombocytopenia). Two patients had mild GI toxicities. One patient had a skin rash. There was no evidence of cardiac, hepatic, or pulmonary toxicities in any of these patients. 25% of subjects had a complete remission (CR), 31% had PR, 23% had SD and 21% had

PD. Of the 13 CRs, 4 were BRCA negative. PFS median for BRCA positive subjects is 12.6 months vs 4.8 months for BRCA negative subjects. OS median for BRCA positive subjects is 24 months vs 16 months for BRCA negative subjects. All of the CR's are alive.

CONCLUSION: Olaparib tablet can be safely administered simultaneously with a weekly regimen of carboplatin and paclitaxel in heavily pretreated ovarian cancer patients. Olaparib appears to be highly effective in BRCA positive subjects. This is the first successful combination of olaparib tablets with carboplatin and paclitaxel that has been well tolerated.

Citation Format: Rivkin SE, Moon J, Iriarte D, Sloan H, Wiseman C, Klee M, Ference K, Drescher C, Veljovich D, Bondurant A, Peters W, Jiang P, Goodman G, Park M, Fer M, Shah C, Johnston E, Kaplan H, Wahl T, Ellis E. PHASE IB/II WITH EXPANSION OF PATIENTS AT THE MTD STUDY OF OLAPARIB PLUS WEEKLY (METRONOMIC) CARBOPLATIN AND PACLITAXEL IN RELAPSED OVARIAN CANCER PATIENTS [abstract]. In: Proceedings of the 11th Biennial Ovarian Cancer Research Symposium; Sep 12-13, 2016; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(11 Suppl):Abstract nr AP30.

De Novo Donor-Specific HLA Antibody Formation in Two Patients With Crigler-Najjar Syndrome Type I Following Human Hepatocyte Transplantation With Partial Hepatectomy Preconditioning

Clinical hepatocyte transplantation is hampered by low engraftment rates and gradual loss of function resulting in incomplete correction of the underlying disease. Preconditioning with partial hepatectomy improves engraftment in animal studies. Our aim was to study safety and efficacy of partial hepatectomy preconditioning in clinical hepatocyte transplantation. Two patients with Crigler-Najjar syndrome type I underwent liver resection followed by hepatocyte transplantation. A transient increase of hepatocyte growth factor was seen, suggesting that this procedure provides a regenerative stimulus. Serum bilirubin was decreased by 50%, and presence of bilirubin glucuronides in bile confirmed graft function in both cases; however, graft function was lost due to discontinuation of immunosuppressive therapy in one patient. In the other patient, serum bilirubin gradually increased to pretransplant concentrations after ≈600 days. In both cases, loss of graft function was temporally associated with emergence of human leukocyte antigen donor-specific antibodies (DSAs). In conclusion, partial hepatectomy in combination with hepatocyte transplantation was safe and induced a robust release of hepatocyte growth factor, but its efficacy on hepatocyte engraftment needs to be evaluated with additional studies. To our knowledge, this study provides the first description of de novo DSAs after hepatocyte transplantation associated with graft loss.

The effect of lung compliance and experience on manual hyperinflation

This study was designed to investigate the factors which affect the safe and effective performance of manual hyperinflation by physiotherapists. To determine this, experienced and student physiotherapists were requested to deliver manual hyperinflations at tidal volumes of 1000mLorpeak inspiratory pressures of 15cm H2O during a series of trials with variations in lung compliance. These hyperinflations were delivered into an artificial lung system. Subjects were blind to random changes in lung compliance and were only allowed the feel of the bag for feedback during testing. It was found that compliance had a significant effect on the tidal volumes and pressures generated, and bothgroups of subjects allowed peak inspiratory pressure to rise significantly when lung compliance was low. Experience, hand size and grip strength of individuals did not influence these results.

Piecing the puzzle together: foreign-born tuberculosis in an immigrant-receiving country

In major immigrant-receiving countries, annual foreign-born tuberculosis (TB) case counts and rates are relatively constant. Why this is so, and who might be a high-yield target for screening for latent TB infection, remain open questions. Foreign-born TB in Canada during 1986-2002 was retrospectively examined using national TB and immigration data as well as census data. Case counts and rates were analysed in relation to demographics, immigration period and time since arrival. Pre-1986 immigrants (n=3,860,853) and 1986-2002 immigrants (n=3,463,283) contributed 8,662 and 9,613 TB cases, respectively. Immigrants arriving ≤ 5 yrs ago and those arriving >10 yrs ago contributed almost equally to the annual foreign-born TB case count despite a 3.5-fold difference in in-country person-yrs. Remarkably stable and relatively low TB incidence was observed among immigrants >10 yrs post-arrival. Conversely, TB incidence within 5 yrs of arrival was dynamic, demonstrating a strong inverse association with time since arrival and higher sensitivity to changes in immigration level than shifts toward higher incidence source countries. Relative constancy in foreign-born TB incidence is explained by a complex convergence of several factors. Immigrants born in high-incidence countries who arrived ≤ 2 yrs ago and were aged 15-34 yrs upon arrival constitute high-yield targets for preventive therapy.

Diabetes outpatient care before and after admission for diabetic foot complications

OBJECTIVE

To assess the number of patients admitted with a diabetic foot complication to a regional teaching hospital over a 12-month period (July 2005 to June 2006) and determine the percentage that went though an optimal diabetes outpatient management pathway before and after this admission.

METHOD

Diabetic inpatients with foot ulcers and infections were identified through the relevant International Classification of Diseases (ICD) codes. Both inpatient and outpatient data were obtained through the local electronic patient management system and review of clinical notes.

RESULTS

Forty-nine patients were admitted to hospital with diabetic foot ulcers or infections during the audit period. Median age was 66 years and 67% were male. The most common admitting speciality was vascular surgery. The main associated procedure was toe amputation. In the six month period before and after the index admission, 63% of patients were seen by a health professional at the diabetes centre before or after the admission. 45% of patients were seen at the diabetes centre before and after the admission; 33% were seen by a podiatrist before and after the admission. However, 37% had no contact with the diabetes Centre and 51% did not see a podiatrist from the diabetes centre at any time during the six months before and after their admission.

CONCLUSION

Despite the availability of a multidisciplinary high risk foot clinic, only 45% of patients admitted to our regional hospital during the audit period followed an interdisciplinary pathway that included specialist diabetes input of some form and only 33% were assessed by a specialist diabetes podiatrist both before and after their hospital admission. A formalised patient pathway is likely to improve clinical management and may minimise further admissions. In this way it will help reduce morbidity and mortality in this high-risk patient group. In the future, this might best be achieved using an electronic referral and decision support system.

Demographic, laboratory and clinical characteristics of HIV-positive tuberculosis cases in Canada

BACKGROUND

Human immunodeficiency virus (HIV) is an important risk factor for the global incidence and mortality of tuberculosis (TB) and has had a tremendous impact on the epidemiology and the control of the disease. The purpose of this study was to determine the demographic, laboratory and clinical characteristics of HIV-positive TB cases in Canada as compared to HIV-negative cases.

METHODS

TB cases reported to the Canadian TB Reporting System (CTBRS) from 1997 to 2006 were retrospectively reviewed and for those with known HIV serostatus, the distributions of age, sex, country of birth, smear and culture positivity, drug resistance, site of disease and treatment outcome were compared.

RESULTS

2710 TB cases had a report of an HIV test with a 12.9% positivity rate. HIV-positive cases were more likely to be 30-44 years old, male, Canadian born non-Aboriginal or African born. Sputum and lymph node biopsies were significantly more likely to be smear-positive and sputum was more likely to be culture positive. Anti-TB drug resistant rates were similar, except for lower streptomycin resistance in new HIV-positive cases. HIV-positive cases were significantly more likely to present with miliary or central nervous system TB, to have multi-system disease, to have lower treatment success rates (66.4% versus 88.5%) and to have a 5.6 higher case-fatality rate.

INTERPRETATION

HIV-positive cases have a different demographic profile, present with more advanced and severe forms of disease, have poorer treatment outcomes and higher mortality. All TB cases should be tested for HIV so as to offer appropriate case management and treatment.

Choice of secondary prevention improves risk factors after acute coronary syndrome: 1-year follow-up of the CHOICE (Choice of Health Options In prevention of Cardiovascular Events) randomised controlled trial

OBJECTIVE

To determine the effect of a new CHOICE (Choice of Health Options In prevention of Cardiovascular Events) programme on cardiovascular risk factors in acute coronary syndrome (ACS) survivors.

DESIGN

Single-blind randomised controlled trial.

SETTING

Tertiary referral hospital in Sydney Australia.

PATIENTS

144 ACS survivors who were not accessing standard cardiac rehabilitation. Data were also collected on a further 64 ACS survivors attending standard cardiac rehabilitation.

INTERVENTION

The CHOICE group (n = 72) participated in a brief, patient-centred, modular programme comprising a clinic visit plus telephone support, encompassing mandatory cholesterol lowering and tailored preferential risk modification. The control group (n = 72) participated in continuing conventional care but no centrally coordinated secondary prevention.

MAIN OUTCOME MEASURES

Values for total cholesterol, systolic blood pressure, smoking status and physical activity.

RESULTS

CHOICE and control groups were well matched at baseline. At 12 months, the CHOICE group (n = 67) had significantly better risk factor levels than controls (n = 69) for total cholesterol (TC) (mean (SEM) 4.0 (0.1) vs 4.7 (0.1) mmol/l, p<0.001), systolic blood pressure (131.6 (1.8) vs 143.9 (2.3) mm Hg, p<0.001), body mass index (28.9 (0.7) vs 31.2 (0.7) kg/m(2), p = 0.025) and physical activity (1369.1 (167.2) vs 715.1 (103.5) METS/kg/min, p = 0.001) as well as a better knowledge of risk factor targets. Also at 1 year, fewer CHOICE participants (21%) had three or more risk factors above widely recommended levels then controls (72%) (p<0.001).

CONCLUSIONS

Participation in a brief CHOICE programme significantly improved the modifiable risk profiles and risk factor knowledge of ACS survivors over 12 months. CHOICE is an effective alternative for dealing with the widespread underuse of existing secondary prevention programmes.

TRIAL REGISTRATION NUMBER

ISRCTN42984084.

Physical activity and health: evidence from a study of deprived communities in England

This study aims to explore the relationship between physical activity levels and the self-reported health status of residents living in deprived communities in England. A cross-sectional interview survey was conducted in communities in receipt of funding from the New Deal for Communities (NDC) regeneration programme. A sample of 848 addresses was selected by random sampling from within each of the 39 NDC areas, and one adult from each household was selected for interview. A total of 19 574 residents were interviewed between July and October 2002. The main outcome measures were physical activity level and health status assessed using four self-reported health measures: health in the last 12 months, health change in the last 12 months, long-standing illness or disability and a mental health-related quality-of-life score. There are large regional and demographic variations in respect of NDC residents' physical activity levels. The areas with the lowest levels of physical activity are mainly located in northern industrial towns. Residents who did little or no physical activity were more than twice as likely to feel that their health was not good (adjusted OR 2.54, 95% CI 2.35-2.75).

Reducing inequalities in access to health care: developing a toolkit through action research

PROBLEM

Healthcare organisations are expected both to monitor inequalities in access to health services and also to act to improve access and increase equity in service provision.

DESIGN

Locally developed action research projects with an explicit objective of reducing inequalities in access.

SETTING

Eight different health care services in the Yorkshire and Humber region, including community based palliative care, general practice asthma care, hospital based cardiology clinics, and termination of pregnancy services.

KEY MEASURES FOR IMPROVEMENT

Changes in service provision, increasing attendance rates in targeted groups.

STRATEGIES FOR CHANGE

Local teams identified the population concerned and appropriate interventions using both published and grey literature. Where change to service provision was achieved, local data were collected to monitor the impact of service change.

EFFECTS OF CHANGE

A number of evidence based changes to service provision were proposed and implemented with variable success. Service uptake increased in some of the targeted populations.

LESSONS LEARNT

Interventions to improve access must be sensitive to local settings and need both practical and managerial support to succeed. It is particularly difficult to improve access effectively if services are already struggling to meet current demand. Key elements for successful interventions included effective local leadership, identification of an intervention which is both evidence based and locally practicable, and identification of additional resources to support increased activity. A "toolkit" has been developed to support the identification and implementation of appropriate changes.

Complications of rigid internal fixation for mandibular fractures

The application of rigid internal fixation to maxillofacial trauma is among the truly great advances that have been made in the field. The use of rigid internal fixation techniques has resulted in many advantages for the patient. Unfortunately, complications have occurred with this technology that are often devastating in their consequences for treatment outcomes. This article addresses some of the problems that stem from the use/misuse of rigid fixation devices in the treatment of mandibular fractures. It presents the most common complications and their management, including malunion, fibrous union, infection/osteitis, and impalement of the tooth roots and/or inferior alveolar canal.

Treatment methods for fractures of the mandibular angle

Fractures of the mandibular angle are plagued with the highest rate of complication of all mandibular fractures. Over the past 8 years, the following six accepted forms of treatment for these fractures were performed on an indigent inner-city population: closed reduction or intra-oral open reduction and nonrigid fixation; extraoral open reduction and internal fixation with an AO/ASIF reconstruction bone plate; and intraoral open reduction and internal fixation using either two 2.0 mm minidynamic compression plates, two 2.4 mm mandibular dynamic compression plates, two noncompression miniplates, or a single noncompression miniplate. This article reviews the results of those treatment modalities when used for the same patient population at one hospital. Results show that the use of either an extraoral open reduction and internal fixation with the AO/ASIF reconstruction plate or intraoral open reduction and internal fixation using a single miniplate was associated with the fewest complications.

Lag screw fixation of mandibular fractures

The lag screw is the simplest means of rigid internal fixation. By virtue of its ability to compress bone fragments without the use of a bone plate, it has wide application and achieves great stability. This article presents techniques to apply lag screws to fractures of the mandibular symphysis, the mandibular body, and the mandibular angle. Results are reviewed in studies of 315 patients whom the author has treated with lag screw fixation. The advantages of the lag screw technique over bone-plate fixation, such as a more rapid application, obviation of the need to adapt a bone plate, minimal displacement of bone segments, and the rapid application of fixation without diminishing the rigidity of the fracture reduction, are discussed, as are the technique's contraindications.

GH is a regulator of IGF2 promoter-specific transcription in human liver

The regulation of the insulin-like growth factor-II gene (IGF2) is complex and involves the usage of four promoters resulting in different 5' untranslated regions, but with a common translated product. The IGF2 gene product is a mitogenic and survival factor that has been suggested to be important for a normal fetal development and cancer. In this paper we present evidence suggesting that the human IGF2 gene is regulated by GH, and that this regulation occurs in a promoter-specific way. Three lines of evidence support this finding. First, in vivo data from patients treated with GH (one injection or daily injections for 5 consecutive days) showed an increase in the IGF2 P2 promoter derived transcript after acute treatment, and of the P4 promoter transcript after short-term treatment while the P1 promoter derived transcript did not show any significant change. Secondly, isolated human liver cells treated with GH for 2 h displayed an upregulation of the P2 promoter derived transcript. Thirdly, employing transfection experiments in GH-receptor positive CHO cells with P2 and P4 promoter-luciferase constructs, an upregulation by GH was evident, while a P1 promoter construct was unresponsive. We suggest that GH may be a physiological regulator of IGF2 in humans.

Condylar process fractures of the mandible

Treatment of condylar process fractures is a highly debated topic because available minimal scientific evidence is concerning outcomes comparing open and closed treatment. Decisions on treatment are therefore based more upon experience, training, and whim rather than upon outcome data. This article presents the author's open and closed techniques for treating condylar process fractures and briefly discusses considerations about which fractures deserve open treatment.

The response of posteroanterior lumbar stiffness to repeated loading

Lumbar posteroanterior (PA) responses are determined by manual examination and are used to guide treatment decisions and interpret changes in symptoms within and between treatments. Mechanical devices that simulate manual assessment have been developed to measure lumbar PA responses. The two variables used to describe lumbar PA responses to mechanical loading are stiffness coefficient K and displacement D30. The purpose of this study was to investigate the behaviour of lumbar PA responses with repeated loading over time. Lumbar PA responses at L4 were measured in 18 pain-free subjects using a mechanical device. Measurements were made for five consecutive loading cycles on three test occasions. The responses were compared between the five cycles within a single test occasion and between three test occasions. An identical procedure was also used to test a set of elastic springs for comparison. There was a significant increase in both stiffness coefficient K and displacement D30 between the first cycle and subsequent cycles of a single test occasion on human subjects. This response which demonstrates an increase in stiffness and displacement between the first and subsequent cycles can be considered a normal response to PA loading. PA stiffness remains constant over several tests both within one day and between days.

The challenges of conducting clinical research: one research team's experiences

Conducting clinical research is an exciting and a rewarding endeavor. Each project is unique and, because of this uniqueness, research studies require considerable planning. Regardless of all the upfront planning, challenges will occur throughout the life of the study. Clinical research projects are rife with obstacles that range from the lack of administrative and physician support to subject attrition. Some of the challenges, such as subject dropout, are not unexpected, whereas other unanticipated issues can blindside a research team. This case study examines several such challenges experienced in one longitudinal study and presents the solutions engineered by the research team to keep the project on track.

The use of a pressure manometer enhances student physiotherapists' performance during manual hyperinflation

The purpose of this study was to determine the effect of using a pressure manometer on the delivery of target airway pressures during manual hyperinflation by student physiotherapists in the laboratory and clinical environments. Manual hyperinflations were delivered under control and feedback conditions where the feedback condition involved manual hyperinflation with a pressure manometer. Compared with control conditions, the availability of a manometer significantly decreased the mean absolute error (9.5 +/- 0.9 cm H2O to 1.4 +/- 0.2 cm H2O) and mean variable error (2.2 +/- 0.3 cm H2O to 1.3 +/- 0.1cm H2O) of peak airway pressures during manual hyperinflation. In addition, the availability of a manometer negated the influence of environment on accuracy. Therefore, the availability of a pressure manometer provided an effective clinical tool that was easily used to provide feedback regarding the peak airway pressures delivered during manual hyperinflation.

From brain to bile. Evidence that conjugation and omega-hydroxylation are important for elimination of 24S-hydroxycholesterol (cerebrosterol) in humans

The brain is the almost exclusive site of formation of 24S-hydroxycholesterol in man, and there is a continuous flux of this oxysterol across the blood-brain barrier into the circulation. The hepatic metabolism of 24S-hydroxycholesterol was studied here by three different approaches: incubation of tritium-labeled 24S-hydroxycholesterol with human primary hepatocytes, administration of tritium-labeled 24S-hydroxycholesterol to a human volunteer, and quantitation of free and conjugated 24S-hydroxycholesterol and its neutral metabolites in ileocecal fluid from patients with ileal fistulae. 24S-Hydroxycholesterol as well as 24R-hydroxycholesterol were converted into bile acids by human hepatocytes at a rate of about 40% of that of the normal intermediate in bile acid synthesis, 7 alpha-hydroxycholesterol. There was also a conversion of 24S-hydroxycholesterol into conjugate(s) of 5-cholestene-3 beta,24S,27-triol at a rate similar to the that of conversion into bile acids. When administered to a human volunteer, labeled 24S-hydroxycholesterol was converted into bile acids at about half the rate of simultaneously administered labeled 7 alpha-hydroxycholesterol. Free, sulfated, and glucuronidated 24S-hydroxycholesterol and 5-cholestene-3 beta,24,27-triol were identified in ileocecal fluid. The excretion of these steroids was about 3.5 mg/24 h, amounting to more than 50% of the total estimated flux of 24S-hydroxycholesterol from the brain. It is concluded that 24S-hydroxycholesterol is a less efficient precursor to bile acids and that about half of it is conjugated and eliminated in bile as such or as a conjugate of a 27-hydroxylated metabolite. The less efficient metabolism of 24S-hydroxycholesterol may explain the surprisingly high levels of this oxysterol in the circulation and is of interest in relation to the suggested role of 24S-hydroxycholesterol as a regulator of cholesterol homeostasis.

Mechanical injury alters volume activated ion channels in cortical astrocytes

Although astrocytic swelling is likely to mediate brain edema and high ICP after traumatic brain injury, the mechanism is not understood. We employed whole cell patch clamp electrophysiology and a stretch injury model to understand whether volume regulating ion currents are altered following cell injury. Mixed rat astrocytes and neurons were co-cultured on deformable silastic membranes. Mild-moderate cell injury was produced using a timed pulse of pressurized air to deform the silastic substrates by 6.5 mm. Then, ion currents were recorded with patch clamp methods. Cells were held at -65 mV and were stepped to +10 mV to monitor current changes.

RESULTS

In unstretched astrocytes, small amplitude currents were obtained under isotonic conditions. Hypotonic solution activated an outwardly-rectifying current which reversed near -40 mV. This current resembled a previously reported anion current whose activation may restore cell volume by mediating a net solute efflux. In contrast, stretch injured cells exhibited a large amplitude, nonrectifying current. This current was not due to non-specific ionic leakage, since it was fully suppressed by the cation channel blocker gadolinium. Activation of novel stretch-activated cation currents may exacerbate cell swelling in injured astrocytes. Stretch injured astrocytes thus express a dysfunctional cation current as opposed to an osmoregulatory anion current. This mechanism, if present in vivo, may contribute to the cytotoxic swelling seen after traumatic brain injury.

The relationship between surgical changes in dentofacial morphology and changes in maximum bite force

PURPOSE

This study determined whether patients with greater surgical changes, and presumably greater normalization of their skeletal morphology, showed greater increases in their maximum voluntary bite forces after orthognathic surgery.

PATIENTS AND METHODS

A total of 104 adult patients (32 males and 72 females) treated with 1 of 8 different orthognathic surgical procedures were examined. Patients' presurgical and postsurgical morphologic and biomechanical measurements were taken from lateral cephalograms. Measurements known to be related to maximum bite force were used in the analysis. Patients' presurgical and postsurgical maximum bite forces were measured at 8 tooth positions (ie, right and left incisors, canines, premolars and molars).

RESULTS

Presurgical and postsurgical morphology and biomechanics variables were strongly correlated with each other, suggesting that orthognathic surgery produced relatively little change in patients' overall craniofacial form. Maximum voluntary bite forces were primarily correlated with variables relating to jaw size-both before and after surgery. No correlations were noted between the increases in maximum voluntary bite forces and surgically produced changes in skeletal morphology and the biomechanics variables.

CONCLUSIONS

Factors other than surgically produced changes in skeletal morphology are responsible for increases in maximum voluntary bite force after orthognathic surgery.

Ionizing radiation modulates vascular endothelial growth factor (VEGF) expression through multiple mitogen activated protein kinase dependent pathways

We investigated the role of radiation-induced mitogen activated protein kinase (MAPK) pathway activity in the regulation of proliferation, cell survival and vascular endothelial growth factor (VEGF) production in primary astrocytes and in T9 and RT2 glioblastoma cells derived from Fisher 344 rats. In these cells, ionizing radiation (2 Gy) caused activation of the MAPK pathway which was blocked by specific inhibitor drugs. Blunting of radiation-induced MAPK activity weakly enhanced radiation-induced apoptosis 24 h after exposure in RT2 cells. Furthermore, blunting of MAPK activation weakly enhanced the ability of radiation to reduce RT2 cell growth in clonogenic growth assays. These findings argue that inhibition of MAPK signaling reduces proliferation and enhances cell killing by ionizing radiation in transformed astrocytes. Proliferation and survival of cancer cells has been linked in vivo to enhanced expression of angiogenic growth factors. Recently we demonstrated that the gene product of a novel rodent radiation-responsive gene, progression elevated gene 3 (PEG-3), could enhance vascular endothelial growth factor (VEGF) promoter activity in rodent fibroblasts, leading to increased VEGF protein levels and tumorigenic behavior in vivo. Thus PEG-3 and VEGF expression could be expected to directly correlate with the oncogenic potential of transformed cells. RT2 cells expressed more PEG-3 and VEGF protein than T9 cells, and were more tumorigenic in vivo than T9 cells. Radiation activated the PEG-3 promoter via MAPK signaling and ectopic over-expression of PEG-3 enhanced both basal MAPK activity and basal VEGF promoter activity. Basal MAPK activity partially correlated with basal VEGF promoter activity and VEGF protein levels in primary astrocytes, T9 and RT2 cells. Radiation increased the activity of the VEGF promoter and VEGF protein levels in primary astrocytes, T9 and RT2 cells which were dependent upon MAPK function. Furthermore, inhibition of AP-1 transcription factor signaling by dominant negative c-Jun (TAM67) also significantly reduced basal, and to a lesser extent radiation-induced, VEGF promoter function in RT2 cells. Collectively, our data demonstrate that radiation-induced MAPK signaling can both protect cells from radiation-induced cell death as well as enhance protein levels of pro-angiogenic factors such as VEGF. Enhanced VEGF expression in RT2 cells may be mediated via MAPK and JNK pathway signaling which converges upon the AP-1 transcription factor complex.

Bite forces after open or closed treatment of mandibular condylar process fractures

PURPOSE

This study compared maximum voluntary bite forces in patients who received either open or closed treatment for fractures of the mandibular condylar process.

PATIENTS AND METHODS

One hundred fifty-five patients (127 male, 28 female) with unilateral fractures of the mandibular condylar process (91 treated closed and 64 treated open) were included in this study. Maximum voluntary bite forces were measured at 6 weeks, 6 months, and 1, 2, and 3 years after fracture. At each trial, unilateral maximum voluntary bite force was measured at 4 different tooth positions bilaterally using a standard transducer. Electromyography (EMG) of the masseter muscles was also recorded during the bite force measurements, and ratios of the working/balancing side EMG were calculated. Analysis of the data was performed using standard statistical methods.

RESULTS

The only significant difference between the 2 samples was in the level of fractures on the condylar process. No patients treated open had fractures of the "head" of the condylar process, whereas there were 11 in the group treated closed. No differences were observed in maximum voluntary bite forces between the 2 treatment groups at any time period, or were there correlations between bite force magnitude and location of the fracture, displacement of the fracture, or any other variable studied. Both groups showed a significant recovery of maximum bite force from the 6-week to the 6-month testing session. For both groups, working/balancing EMG ratios were significantly greater when subjects were biting on the side opposite the fracture. When biting on that side, the working/balancing EMG ratios were higher in the closed treatment group, but the difference did not reach significance.

CONCLUSIONS

Maximum voluntary bite forces in patients treated for mandibular condylar process fractures do not differ significantly when treatment is open or closed. Neuromuscular adaptations to the fractured mandibular condylar process occur in both groups.