Suspected tick-borne flavivirus meningoencephalomyelitis in dogs from the UK: six cases (2021)

OBJECTIVES

Tick-borne encephalitis virus and louping ill virus are neurotropic flaviviruses transmitted by ticks. Epidemiologically, tick-borne encephalitis is endemic in Europe whereas louping ill's predominant geographical distribution is the UK. Rarely, these flaviviruses affect dogs causing neurological signs. This case series aimed to describe the clinical, clinicopathological, and imaging findings, as well as the outcomes in six dogs with meningoencephalitis and/or meningomyelitis caused by a flavivirus in the UK in 2021.

MATERIALS AND METHODS

Observational retrospective case-series study. Clinical data were retrieved from medical records of dogs with positive serological or immunohistochemical results from three different institutions from spring to winter 2021.

RESULTS

Six dogs were included in the study. All dogs presented an initial phase of pyrexia and/or lethargy followed by progressive signs of spinal cord and/or intracranial disease. Magnetic resonance imaging showed bilateral and symmetrical lesions affecting the grey matter of the thalamus, pons, medulla oblongata, and thoracic or lumbar intumescences with none or mild parenchymal and meningeal contrast enhancement. Serology for tick-borne encephalitis virus was positive in five dogs with the presence of seroconversion in two dogs. The viral distinction between flaviviruses was not achieved. One dog with negative serology presented positive immunohistochemistry at post-mortem examination. Three dogs survived but presented neurological sequelae. Three dogs were euthanased due to the rapid progression of the clinical signs or static neurological signs.

CLINICAL SIGNIFICANCE

These cases raise awareness of the presence of tick-borne encephalitis as an emergent disease or the increased prevalence of louping ill virus affecting dogs in the UK.

Evaluation of Radiotherapy Dose and Survival Outcomes for Teenagers, and Young Adults with Nasopharyngeal Carcinoma in UK and Ireland

PURPOSE/OBJECTIVE(S)

Nasopharyngeal carcinoma (NPC) follows a bimodal distribution with a smaller incidence peak in teenagers and young adults (TYAs). In TYAs, an over-whelming proportion are associated with Epstein-Barr virus (EBV). We have evaluated the variation in TYA NPC practice patterns across the UK and Ireland, along with survival outcomes.

MATERIALS/METHODS

We performed a multicenter, observational cohort study, of patients aged 13-25 years, with histologically confirmed NPC, treated between the years 2002-2022. An initial expression of interest was sent to selected centers treating H&N patients in the UK and Ireland. For analysis, patients were assessed based on total prescribed dose, with a cut off for low dose (LD) (≤61.2Gy) versus a high dose (HD)(>61.2Gy).

RESULTS

Ninety-five patients, from 9 centers, were eligible for inclusion. Patient demographics are shown in table1. At a median follow up of 45 months (IQR 23-111), 3-year overall survival (OS) was 98% (95% CI 93%-100%) with LD versus 91% (95% CI 83%-99%) with HD (Hazard ratio (HR) = 3.0; 95% CI 0.3-27, p = 0.3). 3-year progression free survival (PFS) was 84% (95% CI 71%-97%) with LD versus 83% (95% CI 72%-94%) with HD (HR 1.3; 95% CI 0.4-4.0, p = 0.6), and 5-year PFS was 84% (95% CI 71%-97%) with LD versus 83% (95% CI 72%-94%) with HD (HR 1.3; 95% CI 0.4-4.0, p = 0.6). Incidence of distant metastasis (DM) was 9.9%. 2 patients (6%) with T3-T4 tumors, treated with LD, had locoregional failure (LRF) compared to 1 patient (3%) treated with HD.

CONCLUSION

We have demonstrated excellent survival outcomes for the UK & Ireland TYA NPC patients. As the majority of cases in this age group have EBV+ NPC, with survival similar between LD and HD protocols, we propose that pediatric protocols, with lower radiotherapy doses should be considered for all TYA NPC, with the aim of reducing late effects. Additional analysis to better understand the impact of heterogeneity between both groups, including choice of protocol, induction and adjuvant treatment will follow this study. Prospective evaluation, as part of an international collaboration, is required to optimize the management strategy for this rare cohort of patients.

A-43 Effects of Subthreshold Exercise on Post-concussive Symptom Endorsement and Cognition: A Pilot Randomized Clinical Trial

Purpose: The current study examined the effects of subthreshold exercise on symptom endorsement and neurocognitive functioning in adolescents with persisting concussion symptoms (>1 month). Methods: Sixteen participants (age M = 16.2, SD = 1.4) with persisting concussion symptoms were randomly assigned to control or subthreshold exercise intervention groups (Leddy et al., 2019). Participants engaged in concussion education before assignment to 6 weeks (3x weekly) of intervention: control (stretching) or subthreshold exercise. Both groups completed evaluations at baseline, midpoint, and follow-up, including a hybrid battery of assessments (yielding composites of processing speed and memory), a concussion symptom scale (PCS-R), and psychological inventories. Results: Both the intervention group and control group reported significant reduction in concussive symptom severity during the study period (PCS-R Change M = -21.29, SD = 13.54). Baseline endorsement of anxiety significantly differed across groups (p < 0.05); when controlling for anxiety, the intervention group demonstrated greater reduction in symptom endorsement compared to controls (F(1,13) = 7.30, p < 0.05, partial eta2 = 0.40). In contrast, after controlling for performance validity and the baseline anxiety difference, there was no significant difference (p > 0.05) in processing speed performance (partial eta2 = 0.14) or memory performance (partial eta2 = 0.11) by intervention group. Both groups remained generally intact normatively from the baseline to the follow-up evaluation across measures. Conclusions: Current results support the use of subthreshold exercise to reduce persisting symptoms of concussion post-acutely; additionally, results suggest that anxiety significantly impacted response to intervention. Lastly, there was no effect on cognitive indices by the intervention, suggesting that subthreshold exercise may have less impact on cognition than symptom endorsement in the post-acute phase of recovery.

B-48 Effects of Anxiety on Response to a Subsymptom Threshold Exercise Program for Treatment of Persistent Post-Concussive Symptoms: A Pilot Randomized Clinical Trial

Objective

There is a growing literature to support the use of subsymptom threshold exercise for treatment of both acute and chronic post-concussion symptoms. The present study aimed to explore the influence of anxiety on response to exercise intervention for patients with persistent post-concussive symptoms.

Methods

Sixteen adolescents (ages 14-18) with persistent (>1 month) concussion symptoms were randomized into a light, home exercise group and a subsymptom threshold exercise group performed by PT’s (modeled after Leddy et al.,2019). Participants underwent intervention for 6 weeks and completed evaluations at Baseline, Mid-Point, and Follow-up after treatment; evaluations included State-Trait Anxiety Inventory (STAI), the Post-Concussive Scale-Revised (PCS-R), as well as additional measures of emotional functioning, balance disturbance, and neuropsychological functioning.

Results

Average PCS-R endorsement improved by 21 points from Baseline to Follow-up across treatment groups (PCS-R Total Change M = -21.29,SD = 13.54). There were meaningful Baseline differences between intervention groups in STAI state anxiety (p < .05) and STAI trait anxiety (p = 0.51); STAI variables were used as covariates in an ANOVA comparing mean PCS-R Percent Change between treatment and control groups. After removing the influence of anxiety, the intervention groups significantly differed and showed large effect (F(3,13) = 6.94,p < .05,partial eta2 = .41), with the intervention group improving (PCS-R Percent Change M = -63.3,SD = 17.4) more than the control group (PCS-R Percent Change M = -56.8,SD = 27.8).

Conclusion

Exercise intervention appears to be more effective than standard-of-care light activity in the treatment of persistent symptoms in adolescents; however, anxiety may alter response to intervention. Complimentary mental health treatment may augment response to exercise intervention and optimize concussion recovery trajectory in patients with persisting symptoms.

The APTT Response of Pregnant Plasma to Unfractionated Heparin

Pregnancy is associated with a physiological increase in coagulation factors and heparin binding proteins; both can affect the activated partial thromboplastin time (APTT) in response to unfractionated heparin (UFH) invalidating the use of a non-pregnant APTT therapeutic range. We compared the anticoagulant response of UFH added in vitro to the plasma of 13 pregnant (third trimester) and 15 nonpregnant women to determine whether the measured APTT and antifactor Xa activities are lower in pregnancy. Increasing concentrations of UFH were added to platelet-poor plasma from each subject and the APTT and anti-factor Xa activity were measured. The amount of UFH which was reversibly bound and neutralised by plasma heparin binding proteins was assessed by comparing the anti-factor Xa activity before and after addition of low affinity heparin (LAH). Fibrinogen, von Willebrand factor antigen (vWF Ag) and factor VIII levels, were also measured. The APTT response, assessed by the slope of the regression line of log APTT versus added heparin concentration, was attenuated in pregnant plasma (0.76 s/U/mL versus 1.2 s/U/mL, p = 0.005) and was highly correlated to increased non-specific plasma protein binding (47% versus 35% p <0.01) and increased fibrinogen (5.1g/L versus 2.8 g/L, p <0.01) and factor VIII activity (2.7 U/mL versus 1.2 U/mL, p <0.01). Thus, to achieve the same heparin level, pregnant women require higher daily doses of UFH than non-pregnant women. However, if UFH dose adjustments during the third trimester are based upon a non-pregnant APTT therapeutic range, systematic overdosing of pregnant women will result, possibly increasing the risk of bleeding and osteoporosis.

Synovial sarcoma in children and adolescents: the European Pediatric Soft Tissue Sarcoma Study Group prospective trial (EpSSG NRSTS 2005)

BACKGROUND

To report the results of the first European prospective nonrandomized trial dedicated to pediatric synovial sarcoma.

PATIENTS AND METHODS

From August 2005 to August 2012, 138 patients <21 years old with nonmetastatic synovial sarcoma were registered in 9 different countries (and 60 centers). Patients were treated with a multimodal therapy including ifosfamide-doxorubicin chemotherapy and radiotherapy, according to a risk stratification based on surgical stage, tumor size and site, and nodal involvement.

RESULTS

With a median follow-up of 52.1 months (range 13.8-104.4 months), event-free survival (EFS) was 81.9% and 80.7%, and overall survival (OS) was 97.2% and 90.7%, at 3 and 5 years, respectively. The only significant prognostic variable at univariate analysis was the risk group: 3-year EFS was 91.7% for low-risk, 91.2% for intermediate-risk, and 74.4% for high-risk cases. In 24 low-risk patients (completely resected tumor ≤5 cm in size) treated with surgery alone, there were two local relapses and no metastatic recurrences. Among 67 high-risk patients (unresected, or axial tumor or nodal involvement), 66 underwent surgery after neoadjuvant chemotherapy. Response to chemotherapy was 55.2%, including 22.4% cases with complete or major partial remissions, and 32.8% with minor partial remissions.

CONCLUSION

This study demonstrates that collaborative prospective studies on rare pediatric sarcomas are feasible even on a European scale, with excellent treatment compliance. The overall results of treatment were satisfactory, with higher survival rates than those previously published by pediatric groups. Nonetheless, larger, international projects are needed, based on a cooperative effort of pediatric and adult oncologists.

CLINICAL TRIALS NUMBER

European Union Drug Regulating Authorities Clinical Trials No. 2005-001139-31.

Are we ready to "think ahead"? Acceptability study using an innovative end of life planning tool

This is a cross sectional study in 5 GP Training Practices, sample size 100 clinically stable patients, attending for routine care. Purpose of the study was explained and informed written consent was sought. Participants were provided with 'Think Ahead,' an innovative end of life planning tool, devised by The Forum on The End of Life, based on best international practice, presented in a questionnaire format, detailing main decision centres relevant in end of life planning. Participants completed telephone surveys at 1 and 3 weeks, ascertaining their experience with 'Think Ahead;' 92/100 completed both surveys. Results indicate high levels of acceptability and positive experience for most participants. A majority (63%) indicated 'no difficulty' in completing 'Think Ahead;' 74% indicated reported they did not find completing the folder to cause upset; 87% indicated they felt the folder should be more widely available, and 68% indicated they felt 'Think Ahead' would be of general interest. The study was effective in encouraging discussion on end of life issues with family (83%) with 49% indicating they had done so in detail, and 34% indicating having 'done so somewhat,' having read 'Think Ahead; 27% indicated aspects of it were upsetting. Results will be used to inform further development of the tool. General Practice consulting is a suitable context in which to systematically present 'Think Ahead.'

Paediatric and adolescent alveolar soft part sarcoma: A joint series from European cooperative groups

BACKGROUND

Alveolar soft part sarcomas (ASPS) are generally chemo- and radio-resistant mesenchymal tumours, with no standardized treatment guidelines. We describe the clinical behaviour of paediatric ASPS and compare these features to previously reported adult series.

PATIENTS AND METHODS

The clinical data of 51 children and adolescents with ASPS, prospectively enrolled in or treated according to seven European Paediatric trials were analysed.

RESULTS

Median age was 13 years [range: 2-21]. Primary sites included mostly limbs (63%). IRS post-surgical staging was: IRS-I (complete resection) 35%, II (microscopic residual disease) 20%, III (gross residual disease) 18% and IV (metastases) 27%. Only 3 of the 18 evaluable patients (17%) obtained a response to conventional chemotherapy. After a median follow-up of 126 months (range: 9-240), 14/18 patients with IRS-I tumour, 10/10 IRS-II, 7/9 IRS-III and 2/14 IRS-IV were alive in remission. Sunitinib treatment achieved two very good partial responses in four patients. Ten-year overall survival (OS) and event free survival (EFS) was 78.0 ± 7% and 62.8 ± 7% respectively. Stage IV, size >5 cm and T2 tumours had a poorer outcome, but only IRS staging was an independent prognostic factor.

CONCLUSIONS

ASPS is a very rare tumour frequently arising in adolescents and in the extremities, and chemo resistant. Local surgical control is critical. ASPS is a poorly chemo sensitive tumour. For IRS-III/IV tumours, delayed radical local therapies including surgery are essential. Metastatic patients had a poor prognosis but targeted therapies showed promising results.

Pharmacokinetic (PK) interactions between capecitabine (X), oxaliplatin (O) and bevacizumab (A) when used in combination for first-line treatment of metastatic colorectal cancer (MCRC)

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Background: X + O in combination (XELOX) has similar efficacy to FOLFOX-4 in untreated MCRC patients (pts) [1]. The addition of A to irinotecan/5-FU/LV improves progression-free survival (PFS) and overall survival [2], and the potential improvement of adding A to XELOX in MCRC is currently being investigated. Here we present the first PK evaluation of the effects of X on O, O on X, X+A on O, and O+A on X in a multicenter open-label study of pts with untreated MCRC. Methods: Pts received treatment for up to 16 cycles with blood samples for PK analysis taken during cycles 1–3. Treatment: cycle 1: X 1000 mg/m2 orally on morning of d1, O 130 mg/m2 i.v. infusion d2, X 1000 mg/m2 bid orally d5–14, rest d15–21; cycle 2: O 130 mg/m2 i.v. infusion d1 + X 1000 mg/m2 bid orally d1–14, rest d15–21; cycle 3 (XOA): A 7.5 mg/kg i.v. infusion d1 + O 130 mg/m2 i.v. infusion d1 + X 1000 mg/m2 bid orally d1–14, q3w. Treatment with the XOA regimen continued for a further 13 cycles. Safety was evaluated throughout. Results: 36 pts were enrolled; 26 pts completed cycles 1–3 and were evaluable for PK analysis; all pts were evaluable for safety. Baseline characteristics were: M/F 42%/58%; median age 60 years (range 22–74). The primary parameter for PK analysis of X, AUC0-8 of 5’-DFUR, was slightly lower in cycle 2 d1 (XO) and cycle 3 d1 (XOA) vs. cycle 1 d1 (X) (10% and 13% lower, respectively, with CV 27–33%); a decrease in the Cmax of 5’-DFUR was also observed (26% and 36% lower, respectively, with CV 48–54%). However these differences were not considered clinically important. The primary parameter for PK analysis of O, AUC0-8 of free platinum, was very similar among cycle 2 d1 (XO), cycle 3 d1(XOA), and cycle 1 d2 (O), with geometric mean ratios very close to 1. Treatment with X, O and A in combination was generally well tolerated. Conclusions: No large differences in exposure of X or its metabolites, free platinum or total platinum occur when X, O and A are administered in combination. This provides further support for the development of the above dosing regimen in MCRC. References: 1. Cassidy J et al. J Clin Oncol 2004;22:2084–91. 2. Hurwitz H et al. N Eng J Med 2004;350:2335–42.

No significant financial relationships to disclose.

Effect of age and gender on the pharmacokinetics of R667, a novel agent for the treatment of emphysema, in healthy volunteers

The purpose of the present study was to assess the impact of age and gender on the pharmacokinetics (PK) of R667. Thirty six healthy male and female volunteers (12 m 18-45 years; 12 m and 12 f > or = 65 years) received a single 1 mg oral dose of R667. Serial blood samples were collected for determination of plasma R667 and metabolite concentrations. The PK parameters of R667 were similar between elderly males and young males (Cmax = 9.8 vs 9.8 ng/mL; AUC(0-last) = 50.9 vs 47.3 ng x h/mL, respectively). Exposure of R667 increased in elderly females compared to elderly males (Cmax = 13.1 vs 9.8 ng/mL; AUC(0-last) = 60.8 vs 47.3 ng x h/mL, respectively). When the CL/F was corrected for BSA and V/F corrected for weight these differences were no longer evident. In conclusion these exposure differences are not considered clinically relevant, and no dose adjustment of R667 is required based on gender or age.

The APTT response of pregnant plasma to unfractionated heparin

Pregnancy is associated with a physiological increase in coagulation factors and heparin binding proteins; both can affect the activated partial thromboplastin time (APTT) in response to unfractionated heparin (UFH) invalidating the use of a non-pregnant APTT therapeutic range. We compared the anticoagulant response of UFH added in vitro to the plasma of 13 pregnant (third trimester) and 15 nonpregnant women to determine whether the measured APTT and antifactor Xa activities are lower in pregnancy. Increasing concentrations of UFH were added to platelet-poor plasma from each subject and the APTT and anti-factor Xa activity were measured. The amount of UFH which was reversibly bound and neutralised by plasma heparin binding proteins was assessed by comparing the anti-factor Xa activity before and after addition of low affinity heparin (LAH). Fibrinogen, von Willebrand factor antigen (vWF Ag) and factor VIII levels, were also measured. The APTT response, assessed by the slope of the regression line of log APTT versus added heparin concentration, was attenuated in pregnant plasma (0.76 s/U/mL versus 1.2 s/U/mL, p = 0.005) and was highly correlated to increased non-specific plasma protein binding (47% versus 35% p <0.01) and increased fibrinogen (5.1 g/L versus 2.8 g/L, p < 0.01) and factor VIII activity (2.7 U/mL versus 1.2 U/mL, p <0.01). Thus, to achieve the same heparin level, pregnant women require higher daily doses of UFH than non-pregnant women. However, if UFH dose adjustments during the third trimester are based upon a non-pregnant APTT therapeutic range, systematic overdosing of pregnant women will result, possibly increasing the risk of bleeding and osteoporosis.

The registered nurse as a first assistant: the "downunder" experience

In 1996, Bernadette Brennan, RN, was awarded a fellowship from the Australian Confederation of Operating Room Nurses (now known as the Australian College of Operating Room Nurses Ltd.) to travel to the United States to study the role of the Advanced Nurse Practitioner, with an emphasis on the role of the registered nurse first assistant (RNFA). As part of this study, she undertook an RNFA course at Delaware County Community College. This article provides a description of her work to develop an educational program for RNFAs in Australia. Because of the size of the country and the many rural areas needing to be served, her challenge was to devise an accessible program that was also academically rigorous. Her trials as well as her triumphs are presented here.

Tissue distribution and physiologically based pharmacokinetics of antisense phosphorothioate oligonucleotide ISIS 1082 in rat

The aim of this study was to develop a whole body physiologically based model of the pharmacokinetics (PBPK) of the phosphorothioate oligonucleotide (PS-ODN) ISIS 1082 in vivo. Rats were administered an intravenous (i.v.) bolus dose of ISIS 1082 (10 mg/kg plus 3H tracer), and arterial blood and tissues were taken at specific times up to 72 hours. Radioactivity was measured in all samples. The parent compound was determined specifically in blood and tissues at 90 minutes and in liver and kidney also at 24 hours, using capillary gel electrophoresis (CGE). A whole body PBPK model was fitted to the combined blood and tissue radioactivity data using nonlinear regression analysis. CGE analysis indicated that the predominant species in plasma and all tissues is ISIS 1082, together with some n-1 and n-2 metabolites. Total radioactivity primarily reflects these species. The whole body model successfully described temporal events in all tissues. However, to adequately model the experimental data, all tissues had to be partitioned into vascular and extravascular spaces to accommodate the relatively slow distribution of ISIS 1082 out of blood because of a permeability rate limitation. ISIS 1082 distributes extensively into tissues, but the relative affinity varies enormously, being highest for kidney and liver and lowest for muscle and brain. A whole body PBPK model with a permeability rate limited tissue distribution was developed that adequately described events in both blood and tissue for an oligonucleotide. This model has the potential not only to characterize the events in individual tissues throughout the body for such compounds but also to scale across animal species, including human.

Pulmonary presentation of Dirofilaria immitis (canine heartworm) in man

Canine heartworm or Dirofilaria immitis can occasionally infect man. We present the case of a 36-year-old Balkan woman referred to us for a thoracoscopic biopsy of a well defined pulmonary mass. The latter was thoracoscopically resected and proved to be due to Dirofilaria immitis on histopathological examination. To our knowledge this is the second reported case in Western Australia, the first being that reported by Brine et al. The prevalence of the disease in Australia was recognized in 1969 in one study in the state of Queensland, where 12% of 761 dogs at one veterinary clinic and 20% of 296 dogs at another were shown to be infected. Dirofilaria immitis resides in the right ventricle and pulmonary arteries of dogs. The microfilariae are released into the blood stream and are transmitted to secondary hosts by mosquitoes.

Fine needle aspiration biopsy in children

BACKGROUND

Fine needle biopsy (FNB) in children has been slow to gain acceptance compared with the use of the technique in adults where it is regarded as standard clinical practice in screening significant lymphadenopathy and suspicious masses. We report our early experience with FNB in the paediatric population.

METHODS

Fifty-two biopsies were performed between June 1991 and June 1993. The age of the children ranged from 6 months to 14 years (median 2 years, mean 5 years).

RESULTS

A definite diagnosis on cytology alone was obtained in 67%. The pathologist was certain of malignant or nonmalignant potential in 79% (67% benign and 12% malignant) and unsure in 21% (17% benign and 4% malignant). There were no false positive or false negative diagnoses of malignancy. Surgical excision or biopsy was performed in 33%. Fine needle biopsy assisted in planning surgery in 12%. Surgery was necessary for a definite diagnosis in 21% and FNB assisted 42% of the patients to avoid surgery altogether.

CONCLUSIONS

Fine needle biopsy is simple, minimally invasive and useful in the evaluation of children with suspicious lymph nodes and masses.

Overview of topical therapy for common superficial fungal infections and the role of new topical agents

Until recently the treatment options for superficial fungal infections have been limited mainly to the use of fungistatic drugs of the imidazole class, discovered in the 1960s. The recent development of allylamine and benzylamine compounds provides antifungal agents with fungicidal mechanisms of action. Both imidazole and allylamine/benzylamine drugs interfere with the production of ergosterol, an essential component of the fungal cell membrane; however, the newer drugs act at an earlier stage of the metabolic pathway than the azoles and cause an accumulation of squalene in the fungal cell, which leads to cell death. In vitro test results show that allylamine/benzylamine minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) are lower than the MICs and MFCs of azoles tested by the same methods. In studies using animal models of dermatophytosis, results have shown the efficacy of the allylamine/benzylamine drugs to be superior to that of azole drugs. Clinical trials have also shown significant differences favoring allylamine/benzylamine drugs over imidazoles in the treatment of dermatophytosis. The fungicidal drugs provide earlier evidence of efficacy, higher cure rates with shorter treatment periods, and lower relapse rates than imidazoles in direct-comparison studies. The allylamine/benzylamine drugs have also shown high cure rates in patients with candidiasis.

Metabolite kinetics of ondansetron in rat. Comparison of hepatic microsomes, isolated hepatocytes and liver slices, with in vivo disposition

1. The kinetics of hydroxylation and N-demethylation of ondansetron have been determined in freshly isolated hepatocytes, hepatic microsomes and precision-cut liver slices from the male Sprague-Dawley rat. In vivo studies have also been carried out to characterize the pharmacokinetics of ondansetron and in vitro data have been assessed for their value as predictors of hepatic clearance. 2. In the three in vitro systems, the formation of hydroxylated and demethylated metabolites were characterized as a function of substrate concentration by a high-affinity, low-capacity site and a low-affinity, high-capacity site which was not saturated over the concentration range studied (2.5-500 microM). Slices gave consistently higher Km's (20 and 30 microM for hydroxylation and demethylation respectively) than hepatocytes (3 and 13 microM respectively) and microsomes (2 and 5 microM respectively.) The rank order of Vmax and CL(int) was the same for each system; hydroxylation rates exceeding demethylation rates. Although two hydroxylations (7- and 8-hydroxy metabolites) occurred exclusively in microsomes, these are believed to originate from a common precursor. 3. The high CL(int) of ondansetron (150 ml/min/SRW, where SRW is a standard rat weight of 250g) is well predicted by scaling either microsomal clearance for microsomal protein recovery or hepatocyte clearance for hepatocellularity (212 and 135 ml/min/SRW respectively). In contrast, the use of liver slice data scaled to a whole liver substantially underestimates CL(int) (9 ml/min/SRW).

Isolation of Ehrlichia canis from dogs following subcutaneous inoculation

Subcutaneous inoculation of dogs with Ehrlichia canis was investigated as a more appropriate model of canine ehrlichiosis, which is naturally transmitted by arthropod vectors. A dose-dependent response occurred following subcutaneous inoculation of seven groups of dogs with log concentrations of E. canis-infected canine-origin cells. Ehrlichial infection in dogs was defined as concurrence of an increased titer of anti-E. canis immunoglobulin G (IgG) antibody in serum, a decreased platelet concentration, and isolation of E. canis by blood culture. In dogs administered the two lowest doses, no changes were detected. In seven of nine dogs administered three intermediate doses, the only change detected was a transient and mild increase in the anti-E. canis IgG antibody titer in serum. Only two of nine dogs inoculated with the intermediate doses developed an ehrlichial infection. Five of six dogs administered the two highest dose of E. canis developed an ehrlichial infection. These dogs had the highest IgG antibody titers in serum and the earliest isolation of E. canis from blood. In dogs that developed an ehrlichial infection, thrombocytopenia occurred by 28 days after inoculation, while increased IgG antibody titers in serum and blood cultures positive for E. canis occurred as early as 14 days postinoculation. Thrombocytopenia and seroconversion occurred later in the course of infection than previously reported for ehrlichial infections induced by intravenous inoculation. The route of administration and E. canis inoculum size can influence the course of ehrlichial infection and should be regarded as important variables in experimentally induced canine ehrlichiosis.

Comparison of ketoconazole and fluconazole as cytochrome P450 inhibitors. Use of steady-state infusion approach to achieve plasma concentration-response relationships

The ability of two azole antifungal agents, ketoconazole and fluconazole, to inhibit hepatic cytochrome P450 activity in vivo in the rat has been determined. To make a valid comparison, differences in pharmacokinetic properties between the azoles were accounted for by using an infusion approach to maintain steady-state plasma concentrations over a range of 1-48 mg/liter. Both compounds showed a maximum inhibitory effect, assessed by a reduction in antipyrine clearance, of approximately 75%. The relationship between steady-state plasma concentration and the degree of inhibition of antipyrine clearance was nonlinear for both azoles. However, the inhibitory effect resulted at lower concentrations for ketoconazole than for fluconazole. Analysis of these data provided Ki values of 3 and 10 microM, for ketoconazole and fluconazole, respectively, based on plasma concentration of azole. This difference in activity is 2 orders of magnitude greater when Ki values are expressed in terms of unbound concentration in the blood, which may be more representative of hepatic tissue concentrations. Ki values based on unbound drug concentration are 0.07 and 8.7 microM for ketoconazole and fluconazole, respectively. These data confirm the conclusions based on in vitro findings that ketoconazole is a more inhibitory of mammalian cytochrome P450 isoenzymes than fluconazole.

In vivo disposition of caffeine predicted from hepatic microsomal and hepatocyte data

The kinetics of caffeine metabolism has been investigated in freshly isolated hepatocytes, hepatic microsomes, and in vivo in male Sprague-Dawley rats. A simple Michaelis-Menten model provides an adequate description of each of the three sets of data. There is reasonable agreement between the KM values for the three systems (56-200 microM). Vmax values for hepatocytes and microsomes show good agreement when expressed in the same units using scaling factors for hepatic cellularity and microsomal protein yield [315 and 420 nmol/min/standard rat weight (SRW), respectively]. Both values slightly exceed the in vivo-determined Vmax (190 nmol/min/SRW). Taking the Vmax/KM ratio (intrinsic clearance) as the basis for scaling, the in vitro data from both the hepatocyte (2.6 ml/min/SRW) and microsomal (2.7 ml/min/SRW) studies provide a good prediction of the in vivo total body clearance (3.4 ml/min/SRW).

Greening the OR: an Australian perspective

1. Many hospitals in Australia have become proactive about environmental issues, including use of plastics, disposable drapes, and glutaraldehyde; laundering of linen; and disposal of waste. 2. Although some standards are not mandated (as in the United States), timely, comprehensive guidelines are being published. 3. Environmental advocacy demonstrates the resourcefulness and creativity of perioperative nurses, as well as a commitment to preserving the environment for future generations.

T lymphocytes adhere to airway smooth muscle cells via integrins and CD44 and induce smooth muscle cell DNA synthesis

Asthma is a disease of airway inflammation and hyperreactivity that is associated with a lymphocytic infiltrate in the bronchial submucosa. The interactions between infiltrating T lymphocytes with cellular and extracellular matrix components of the airway and the consequences of these interactions have not been defined. We demonstrate the constitutive expression of CD44 on human airway smooth muscle (ASM) cells in culture as well as in human bronchial tissue transplanted into severe combined immunodeficient mice. In contrast, basal levels of intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) expression are minimal but are induced on ASM by inflammatory mediators such as tumor necrosis factor alpha (TNF-alpha). Activated, but not resting T cells, adhere to cultured ASM; stimulation of the ASM with TNF-alpha enhanced this adhesion. Adhesion was partially blocked by monoclonal antibodies (mAb) specific for lymphocyte function-associated antigen 1 (LFA-1) and very late antigen 4 (VLA-4) on T cells and ICAM-1 and VCAM-1 on ASM cells. The observed integrin-independent adhesion was mediated by CD44/hyaluronate interactions as it was inhibited by anti-CD44 mAb 5F12 and by hyaluronidase. Furthermore, the adhesion of activated T lymphocytes induced DNA synthesis in growth-arrested ASM cells. Thus, the interaction between T cells and ASM may provide insight into the mechanisms that induce bronchial inflammation and possibly ASM cell hyperplasia seen in asthma.

Color Doppler imaging of the thyroid gland in a fetus with congenital goiter: a case report

Fetal goiter is a rare disorder, usually associated with maternal thyroid disease. Antenatal diagnosis of fetal goiter is crucial for the immediate postpartum management of these neonates. A case report is presented of an antenatally diagnosed fetal goiter induced by antithyroid medications. Color Doppler was used to demonstrate a high flow pattern that, unlike in the adult goiter, was associated with hypothyroidism in the neonate. A scan of fetal neck region is recommended in patients with current or previous history of thyroid disease, or if neck extension is noted on routine examination of fetal spine.

Disposition of azole antifungal agents. I. Nonlinearities in ketoconazole clearance and binding in rat liver

The disposition of ketoconazole was characterized in the rat over a wide dose/concentration range. Bolus dose (0.03-10 mg/kg) studies indicate that plasma concentration-time profiles for ketoconazole are not superimposable when dose normalized because of nonlinearities occurring in both volume of distribution and clearance. The volume of distribution decreases from 3 to less than 1 L/kg, while the plasma clearance decreases 10-fold from 25 mL/min/kg as the dose is escalated. From these results, infusion rates were calculated to maintain the plasma concentrations achieved with particular bolus doses. The curvilinear relationship between steady-state plasma concentration (0.015-8.3 mg/L) and ketoconazole infusion rate (0.021-2.45 mg/hr/kg) was analyzed in terms of Michaelis-Menten kinetics. A Vmax of 3.2 mg/hr/kg and Km of 2.1 mg/L were obtained by nonlinear regression analysis. At the end of the ketoconazole infusion, liver, adrenals and kidneys were removed and assayed for ketoconazole. Tissue-to-plasma partition coefficients for the liver and adrenals showed a marked dependence upon steady-state plasma concentration. Both parameters (liver, 22; and adrenals, 53) showed a decrease of approximately 10-fold as the plasma concentrations were increased. In contrast, the kidney:plasma partition coefficient (1.8), blood:plasma concentration ratio (0.6), and plasma binding (96%) of ketoconazole did not show a concentration dependence over the range studied. It is concluded that the liver is an important determinant of ketoconazole's volume of distribution and that saturation of this process accounts largely for the reduction in volume of distribution with increasing dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Cloacal exstrophy: prenatal diagnosis before rupture of the cloacal membrane

Embryologically, cloacal exstrophy is thought to result from persistence and subsequent rupture of the infraumbilical cloacal membrane during the fifth embryonic week. We report a case of cloacal exstrophy in which a prenatal diagnosis was made prior to rupture of the cloacal membrane. A routine ultrasound at 17 weeks' gestation demonstrated monoamniotic twins. One twin was normal, but the other was found to have a sacral myelomeningocele, "rocker-bottom" feet, splaying of the pubic rami, and a large cystic mass protruding from the infraumbilical anterior abdominal wall. A repeat ultrasound was performed at 22 weeks, with the same findings. At 26 weeks, further examination showed disappearance of the abdominal cyst, a small omphalocele, no demonstrable bladder, and the suggestion of prolapsed bowel inferior to the umbilical cord insertion. After delivery at 34 weeks, the abnormal twin was found to have the typical findings of cloacal exstrophy, myelomeningocele, bilateral lower limb anomalies, and extremely foreshortened small bowel. Rupture of the presumed cloacal membrane after 22 weeks in this case is inconsistent with our current understanding of the embryology of this anomaly, and should stimulate a reexamination of the current concepts. If the characteristic features are recognized, cloacal exstrophy can be diagnosed by prenatal ultrasound, permitting prenatal counseling and appropriate perinatal management.

Effect of inhaled furosemide on the bronchial response to methacholine and cold-air hyperventilation challenges

Inhaled furosemide has been recently demonstrated to inhibit the bronchoconstrictive effects of exercise, ultrasonically nebulized distilled water, and antigen challenge. The presumed mechanism of action of these challenges is through mast cell degranulation. We report on the effect of inhaled furosemide on cold-air hyperventilation challenge (CAHC) and methacholine challenge. We studied 10 subjects with mild to moderate asthma in a double-blind, placebo-controlled, crossover study. Inhaled furosemide did not affect FEV1 in the hour after inhalation, and there was no significant difference between placebo or furosemide on the dose of methacholine causing a 20% fall in FEV1. Our results demonstrated inhaled furosemide significantly attenuated the bronchoconstrictive effect at 6 and 9 minutes after CAHC (p less than 0.05 and 0.029, respectively) when furosemide was compared to placebo and approached significance at 12 and 15 minutes after CAHC (p = 0.052 and 0.56, respectively). Inhaled furosemide attenuates CAHC but does not effect methacholine-induced bronchoconstriction.

Anisotropic reflectance characteristics of natural Earth surfaces

The patterns of reflection of solar radiation from cloud, water, and land surfaces were measured with an aircraft-borne medium resolution radiometer. Reflectances in the 0.2-4.0-micro and 0.55-0.85-micro portions of the electromagnetic spectrum were investigated. Results indicate that the reflectance characteristics of most of the surface types measured are anisotropic. The anisotropy is dependent on the type of surface and the angles of incidence and reflection. In general, the anisotropy increases with increasing solar zenith angle. Clouds and forests show similar reflectance patterns, with forward and backward scattering peaks. Ocean surfaces yield a pattern similar to those of the clouds and forests but with an additional peak which is associated with sun glitter. Reflectances measured in the 0.2-4.0-micro band are generally lower than those in the 0.55-0.85-micro band under cloudy conditions. Anisotropy and spectral bandwidth should be accounted for when computing the albedo of the earth from narrow field-of-view measurements from satellites; otherwise, large errors may be expected to occur.