The impact of extended half-life factor concentrates on patient reported health outcome measures in persons with hemophilia A and hemophilia B

BACKGROUND

Recombinant factors VIII and IX Fc (rFVIIIFc/rFIXFc) were the only available extended half-life (EHL) products in Canada during 2016 to 2018.

OBJECTIVES

To evaluate if patient-reported outcome measures (PROMs) improved in Canadian persons with hemophilia who switched from standard half-life (SHL) to EHL products (rFVIIIFc/rFIXFc).

PATIENTS/METHODS

This prospective cohort study enrolled persons with moderate or severe hemophilia aged ≥6 years who switched to rFVIIIFc/rFIXFc (2016-2018) and those who remained on SHL. Health-related quality of life (HRQoL) was assessed using the Haemophilia-specific Quality of Life (Haem-A-QoL) and 36-item Short-Form Survey (SF-36) at baseline, 3-months, 12 months, and 24 months. Other PROMs included the Work Productivity and Impairment Questionnaire, chronic pain scale, partner/parent ratings of mood, International Physical Activity Questionnaire, and Treatment Satisfaction Questionnaire for Medication. We identified meaningful changes using minimally important difference for SF-36 and responder definition for Haem-A-QoL.

RESULTS

We enrolled 25 switchers (16 rFVIIIFc, 9 rFIXFc) and 33 nonswitchers. Those switched to rFVIIIFc/rFIXFc had improved overall HRQoL, and improved subscale physical activity, mental health, and social functioning at 3 months. The rFIXFc switchers had improved chronic pain and ability to engage in normal activities while the rFVIIIFc switchers had improved treatment satisfaction. There was no change in work impairment after the switch. Observed improvement disappeared by 24 months in most domains.

CONCLUSION

Switching from SHL to rFVIIIFc/rFIXFc resulted in short-term meaningful improvement in overall HRQoL and other PROMs in a small proportion. Longitudinal changes on PROMs are affected by ceiling effects and response shift, warranting further studies in instrument optimization in the era of EHL and nonfactor products.

Factor product utilization and health outcomes in patients with haemophilia A and B on extended half-life concentrates: A Canadian observational study of real-world outcomes

INTRODUCTION

Recombinant factors VIII and IX Fc (rFVIIIFc/rFIXFc) became available in Canada in 2016 and were the only extended half-life (EHL) factor concentrates available in Canada until 2018.

OBJECTIVES

We aim to describe the change in product utilization in Canadians who switched to rFVIIIFc/rFIXFc.

METHODS

This prospective and retrospective cohort study enrolled males aged ≥6 years with moderate or severe haemophilia who switched to rFVIIIFc/rFIXFc and those who remained on standard half-life (SHL) between 2016 and 2018. Factor utilization and annualized bleeding rates (ABR) were collected at baseline, 1-year and 2-years. Due to low prospective enrolment (n = 25 switchers), prospective and retrospective data were pooled.

RESULTS

125 switchers (93 rFVIIIFc, 32 rFIXFc) and 33 non-switchers were included. The median age was 17 (rFVIIIFc) and 38 years (rFIXFc). Prior to switch, over 80% were on prophylaxis. There was a statistically significant reduction in the prescribed weekly prophylactic dose after the switch to rFVIIIFc/rFIXFc for all age groups, with a corresponding reduction (15-16%) in actual annualized FIX utilization in switchers (combined adults and children) to rFIXFc, and a smaller non-significant reduction in actual annualized FVIIII utilization (7%) in children who switched to rFVIIIFc. A significant reduction in the median ABR was only observed in children who switched to rFVIIIFc, but not in adults who switched to rFVIIIFc or rFIXFc.

CONCLUSION

Switching from SHL to EHL products led to a small reduction in factor utilization, while preserving a low ABR in children and adults with haemophilia. Further patient-reported outcomes data will further elucidate the role of EHL in the haemophilia landscape.

Women and inherited bleeding disorders - A review with a focus on key challenges for 2019

The area of women and inherited bleeding disorders has undergone quick expansion in recent years. More patients are being identified and expertise to diagnose and manage these patients is now essential for practising physicians. Programs to help educate and empower patients and caregivers are now in place. Common inherited bleeding disorders affecting women include von Willebrand disease (VWD), inherited platelet disorders, and rare inherited bleeding disorders such as factor VII (FVII) deficiency and factor XI (FXI) deficiency. Specific clinical tools have been developed to help clinicians and patients screen for the presence of these bleeding disorders in both adult and pediatric populations. Affected women can experience heavy menstrual bleeding and resulting iron deficiency anemia, postpartum hemorrhage, and hemorrhagic ovarian cysts which need to be properly managed. Excessive bleeding can adversely affect quality of life in these women. Front line therapy for bleeding in mild cases focuses on the use of non-specific hemostatic agents such as DDAVP ®, tranexamic acid and hormonal agents but specific factor replacement and/or blood products may be required in more severe cases, in severe bleeding or as second line treatment when bleeding is not responsive to first line agents. Iron status should be optimised in these women especially in pregnancy and use of an electronic app can now help clinicians achieve this. These patients should ideally be managed by a multidisciplinary team whenever possible even remotely. Although clinical research has closed some knowledge gaps regarding the diagnosis and management of these women, there remains significant variation in practise and lack of evidence-based guidelines still exists in many spheres of clinical care in which caregivers must rely on expert opinion. Ongoing efforts in education and research will continue to improve care for these women and restore quality of life for them.

An overview of inherited factor VII deficiency

Factor VII (FVII) deficiency is the most common of the Rare Inherited Coagulation Disorders. The inheritance is autosomal recessive but there is variable penetrance. Overall there is poor correlation between the FVII level and the bleeding phenotype. Heterozygotes may have significant bleeding and severe homozygotes, or compound heterozygotes can be asymptomatic. Typically, homozygotes have FVII levels <10% and heterozygotes have levels above that. In most cases bleeding is uncommon with FVII levels>10-20%. A personal and family history is essential to determine the bleeding risk and to plan for surgical and obstetrical prophylaxis. Severe bleeding complications including central nervous system bleeding, gastrointestinal system bleeding and bleeding into the joints occurs in 10-15% of FVII deficient patients. Mucocutaneous bleeding is a common symptom but 30% of patients are asymptomatic. Fifty to 69% of women have heavy menstrual bleeding. Due to the limited number of publications regarding this rare disorder there are no consensus guidelines. There is registry data which has led to the best recommendations for treatment of bleeding episodes, initiation of long-term prophylaxis in addition to surgical plus ante and peripartum prophylaxis. Recombinant FVII concentrate is the best replacement therapy and a review of treatment and prophylaxis dosing is discussed.

Canadian evidence-based guideline for the first-line treatment of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (cll) is the most common adult leukemia in North America. In Canada, no unified national guideline exists for the front-line treatment of cll; provincial guidelines vary and are largely based on funding. A group of clinical experts from across Canada developed a national evidence-based treatment guideline to provide health care professionals with clear guidance on the first-line management of cll. Consensus recommendations based on available evidence are presented for the first-line treatment of cll.

Goal Attainment Scaling for haemophilia (GAS-Hēm): testing the feasibility of a new patient-centric outcome measure in people with haemophilia

INTRODUCTION

To address the need for a patient-reported outcome that can measure clinically and personally meaningful change in people with haemophilia (PwH) on prophylaxis, an approach based on Goal Attainment Scaling (GAS) was developed: the GAS-Hēm.

AIM

To establish real-world feasibility of GAS-Hēm in PwH.

METHODS

Patients aged 5-65 years were enroled from four North American centres for a 12-week study. The primary outcome was the proportion of participants who completed GAS-Hēm interviews at baseline, 6 and 12 weeks. GAS-Hēm scores were obtained by subject- and clinician-rated goal attainment at Weeks 6 and 12, and compared with quality of life (QoL) measures and annualized bleed rate (ABR) for construct validity. Goals were evaluated qualitatively for content validity. Responsiveness was calculated using standardized response means (SRM).

RESULTS

Forty-two participants set 63 goals. Participants preferred to define (37/63) their own goals or further individualize (23/63) from the GAS-Hēm menu. Thirty of the 37 self-defined goals were matched to goals on the GAS-Hēm menu. The most common goal areas were: weight, exercise and nutrition (n = 17); leisure activities (n = 8); and joint problems (n = 7). Both participant- and clinician-rated GAS-Hēm scores at 6 weeks (n = 40) and 12 weeks (n = 41) demonstrated satisfactory goal attainment (SRM [subject-rated] at 12 weeks for adult and paediatric groups was 1.25 and 1.16, respectively). Correlations of GAS-Hēm scores with QoL measures and ABR were uniformly small.

CONCLUSION

GAS-Hēm was feasible and tapped constructs not captured by ABR or QoL measures.

Acquired hemophilia A: A rare cause of gross hematuria

Acquired hemophilia A is a rare condition caused by spontaneous development of factor VIII inhibitor. This condition most commonly presents with multiple hemorrhagic symptoms and isolated hematuria is exceedingly rare. Early diagnosis is important, as this condition carries a high mortality rate (13-22%). We present a case of an 82-year-old man with isolated hematuria caused by a factor VIII inhibitor who was successfully treated with recombinant activated factor VII concentrate, as well as prednisone and cyclophosphamide.

Randomized Phase III Trial Comparing ABVD Plus Radiotherapy With the Stanford V Regimen in Patients With Stages I or II Locally Extensive, Bulky Mediastinal Hodgkin Lymphoma: A Subset Analysis of the North American Intergroup E2496 Trial

PURPOSE

The phase III North American Intergroup E2496 Trial (Combination Chemotherapy With or Without Radiation Therapy in Treating Patients With Hodgkin's Lymphoma) compared doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) with mechlorethamine, doxorubicin, vincristine, bleomycin, vinblastine, etoposide, and prednisone (Stanford V). We report results of a planned subgroup analysis in patients with stage I or II bulky mediastinal Hodgkin lymphoma (HL).

PATIENTS AND METHODS

Patients were randomly assigned to six to eight cycles of ABVD every 28 days or Stanford V once per week for 12 weeks. Two to 3 weeks after completion of chemotherapy, all patients received 36 Gy of modified involved field radiotherapy (IFRT) to the mediastinum, hila, and supraclavicular regions. Patients on the Stanford V arm received IFRT to additional sites ≥ 5 cm at diagnosis. Primary end points were failure-free survival (FFS) and overall survival (OS).

RESULTS

Of 794 eligible patients, 264 had stage I or II bulky disease, 135 received ABVD, and 129 received Stanford V. Patient characteristics were matched. The overall response rate was 83% with ABVD and 88% with Stanford V. At a median follow-up of 6.5 years, the study excluded a difference of more than 21% in 5-year FFS and more than 16% in 5-year OS between ABVD and Stanford V (5-year FFS: 85% v 79%; HR, 0.68; 95% CI, 0.37 to 1.25; P = .22; 5-year OS: 96% v 92%; HR, 0.49; 95% CI, 0.16 to 1.47; P = .19). In-field relapses occurred in < 10% of the patients in each arm.

CONCLUSION

For patients with stage I or II bulky mediastinal HL, no substantial statistically significant differences were detected between the two regimens, although power was limited. To the best of our knowledge, this is the first prospective trial reporting outcomes specific to this subgroup, and it sets a benchmark for comparison of ongoing and future studies.

Cyclobutane pyrimidine dimers are photosensitised by carprofen plus UVA in human HaCaT cells

Every year in the UK about 75,000 cases of non-melanoma skin cancer (NMSC) are registered, and about 9500 people are diagnosed with cutaneous melanoma (CM). The main risk factor for these cancers is exposure to sunlight. The effects of light on skin are wavelength dependent, with wavelengths in the UVB waveband (280-315 nm) being the most carcinogenic. UVB is directly absorbed by DNA, producing dimeric pyrimidine photoproducts including cyclobutane pyrimidine dimers (CPD) and pyrimidine (6-4) pyrimodone photoproducts (6-4PP). However UVA (315-400 nm) can also produce CPD, induce skin tumours in mice, and has been shown to be mutagenic in cell culture. Although the precise role of UVA in human skin cancer remains to be elucidated, it comprises the major portion of solar UV radiation, transmits through window glass and can be delivered in high doses from tanning lamps. Non-steroidal anti-inflammatory drugs (NSAIDs), in particular the 2-aryl propionic acid derivatives, are a well-documented group of photosensitising chemicals producing clinical phototoxic and photoallergic reactions. We have used carprofen, a model compound from this group to see if it could amplify the effects of UVA and contribute to the formation of CPD by UVA. Preliminary work has shown that carprofen combined with low doses of UVA (lambda(max): 365 nm; 5 J/cm(2)) can produce both strand breaks (SB) and CPD in human skin or blood cells. CPD were detected indirectly by both an immunofluorescence method and as T4 endonuclease V sensitive sites in the comet assay. These findings show that compounds other than fluoroquinolones and psoralen derivatives may contribute to CPD formation in skin cells in combination with UVA.

Bendamustine is effective therapy in patients with rituximab-refractory, indolent B-cell non-Hodgkin lymphoma: results from a Multicenter Study

BACKGROUND

Bendamustine hydrochloride is a novel alkylating agent. In this multicenter study, the authors evaluated the efficacy and toxicity of single-agent bendamustine in patients with rituximab-refractory, indolent B-cell lymphoma.

METHODS

Eligible patients (N = 100, ages 31-84 years) received bendamustine at a dose of 120 mg/m(2) by intravenous infusion on Days 1 and 2 every 21 days for 6 to 8 cycles. Histologies included follicular (62%), small lymphocytic (21%), and marginal zone (16%) lymphomas. Patients had received a median of 2 previous regimens (range, 0-6 previous regimens), and 36%were refractory to their most recent chemotherapy regimen. Primary endpoints included overall response rate (ORR) and duration of response (DOR). Secondary endpoints were safety and progression-free survival (PFS).

RESULTS

An ORR of 75% (a 14% complete response rate, a 3% unconfirmed complete response rate, and a 58% partial response rate) was observed. The median DOR was 9.2 months, and median PFS was 9.3 months. Six deaths were considered to be possibly treatment related. Grade 3 or 4 (determined using National Cancer Institute Common Toxicity Criteria [version 3.0.19]. reversible hematologic toxicities included neutropenia (61%), thrombocytopenia (25%), and anemia (10%). The most frequent nonhematologic adverse events (any grade) included nausea (77%), infection (69%), fatigue (64%), diarrhea (42%), vomiting (40%), pyrexia (36%), constipation (31%), and anorexia (24%).

CONCLUSIONS

Single-agent bendamustine produced a high rate of objective responses with acceptable toxicity in patients with recurrent, rituximab-refractory indolent B-cell lymphoma.

Phase II Multicenter Study of Bendamustine Plus Rituximab in Patients With Relapsed Indolent B-Cell and Mantle Cell Non-Hodgkin's Lymphoma

Purpose

Bendamustine HCl is a bifunctional mechlorethamine derivative with clinical activity in the treatment of non-Hodgkin's lymphoma. This study evaluated bendamustine plus rituximab in 67 adults with relapsed, indolent B-cell or mantle cell lymphoma without documented resistance to prior rituximab.

Patients and Methods

Patients received rituximab 375 mg/m2intravenously on day 1 and bendamustine 90 mg/m2intravenously on days 2 and 3 of each 28-day cycle for four to six cycles. An additional dose of rituximab was administered 1 week before the first cycle and 4 weeks after the last cycle. Sixty-six patients (median age, 60 years) received at least one dose of both drugs.

Results

Overall response rate was 92% (41% complete response, 14% unconfirmed complete response, and 38% partial response). Median duration of response was 21 months (95% CI, 18 to 24 months). Median progression-free survival time was 23 months (95% CI, 20 to 26 months). Outcomes were similar for patients with indolent or mantle cell histologies. The combination was generally well tolerated; the primary toxicity was myelosuppression (grade 3 or 4 neutropenia, 36%; grade 3 or 4 thrombocytopenia, 9%).

Conclusion

Bendamustine plus rituximab is an active combination in patients with relapsed indolent and mantle cell lymphoma.

Bendamustine in Patients With Rituximab-Refractory Indolent and Transformed Non-Hodgkin's Lymphoma: Results From a Phase II Multicenter, Single-Agent Study

Purpose

Bendamustine hydrochloride is an alkylating agent with novel mechanisms of action. This phase II multicenter study evaluated the efficacy and toxicity of bendamustine in patients with B-cell non-Hodgkin's lymphoma (NHL) refractory to rituximab.

Patients and Methods

Patients received bendamustine 120 mg/m2intravenously on days 1 and 2 of each 21-day cycle. Outcomes included response, duration of response, progression-free survival, and safety.

Results

Seventy-six patients, ages 38 to 84 years, with predominantly stage III/IV indolent (80%) or transformed (20%) disease were treated; 74 were assessable for response. Twenty-four (32%) were refractory to chemotherapy. Patients received a median of two prior unique regimens. An overall response rate of 77% (15% complete response, 19% unconfirmed complete response, and 43% partial) was observed. The median duration of response was 6.7 months (95% CI, 5.1 to 9.9 months), 9.0 months (95% CI, 5.8 to 16.7) for patients with indolent disease, and 2.3 months (95% CI, 1.7 to 5.1) for those with transformed disease. Thirty-six percent of these responses exceeded 1 year. The most frequent nonhematologic adverse events included nausea and vomiting, fatigue, constipation, anorexia, fever, cough, and diarrhea. Grade 3 or 4 reversible hematologic toxicities included neutropenia (54%), thrombocytopenia (25%), and anemia (12%).

Conclusion

Single-agent bendamustine produced durable objective responses with acceptable toxicity in heavily pretreated patients with rituximab-refractory, indolent NHL. These findings are promising and will serve as a benchmark for future clinical trials in this novel patient population.

Sequential response-adapted induction and consolidation regimens idarubicin/cytarabine and mitoxantrone/etoposide in adult acute myelogenous leukemia: 10 year follow-up of a study by the Canadian Leukemia Studies Group

PURPOSE

The Canadian Leukemia Studies Group (CLSG) sought to test the safety and efficacy of response-adapted, non-cross resistant chemotherapy in de novo acute myeloid leukemia (AML). The combinations of idarubicin 12 mg/m(2)/d on days 1 - 3 and Ara-C (200 mg/m(2)/d) on days 1 - 7 (IDAC) followed by mitoxantrone 10 mg/m(2)/day, and etoposide 100 mg/m(2)/day, on days 1 - 5 (NOVE) were used according to patient response to induction and consolidation.

PATIENTS AND METHODS

In this multi-centre open-label phase II study, 140 patients up to age 80 were given induction with IDAC. Patients were entered between March 1993 and August 1995. If patients had persistent blasts at day 14 or on recovery, they were given NOVE. As consolidation, patients achieving complete remission (CR) with IDAC were given 1 further cycle of IDAC and 1 cycle of NOVE. Patients achieving CR after NOVE were given 2 further cycles of NOVE.

RESULTS

76% of all patients achieved remission after IDAC +/- NOVE, 81% in patients aged < or =60 years and 67% in patients aged >60. Overall, induction mortality was 11% and toxicity was similar to other cooperative group studies. Median follow-up was 104.0 months with 95% CI: (100.0, 105.2). Median overall survival (OS) in responding patients < or =60 was not reached: of the 79 responders < or =60, 35 died. The median disease free survival (DFS) in these responding patients was 22.7 (14.9, na) months. Median OS and DFS in responding patients >60 was 10.0 (7.3, 15.2) months and 7.5 (6.2, 15.2) months, respectively.

CONCLUSION

The results of this trial are very encouraging and suggest that there may be long-term benefit to this method. On the basis of these results, a randomized phase III trial has been performed.

Comparison of a nomogram and physician-adjusted dosage of warfarin for prophylaxis against deep-vein thrombosis after arthroplasty

BACKGROUND

Warfarin is an effective agent for prophylaxis against deep-vein thrombosis following total hip or knee arthroplasty. However, management with warfarin in the postoperative setting is problematic because of the need for anticoagulant monitoring. We developed a nomogram for the dosing of warfarin that was specific for joint arthroplasty. The objective of this study was to compare the performance of this nomogram with that of physician-adjusted dosing of warfarin for patients undergoing total hip or knee arthroplasty.

METHODS

The study involved two cohort trials. The historical control group consisted of 1024 patients who underwent total hip or knee arthroplasty during the course of a clinical trial (the Post-Arthroplasty Screening Study [PASS]) in which all warfarin dose adjustments were made by two hematologists. The first dose of warfarin was given on the evening of the surgery, and the warfarin dose was adjusted daily on the basis of the international normalized ratio and was discontinued at the time of discharge from the hospital. In the PASS study, the dosage of warfarin was designed to prolong the international normalized ratio to 1.7 by postoperative day 4 and to maintain it between 1.8 and 2.5 until discharge from the hospital. Subsequently, a warfarin nomogram was developed on the basis of the dose adjustments used in the PASS study, and it was used prospectively to manage a cohort of 729 patients undergoing total hip or knee arthroplasty. In the nomogram cohort, the initial dose of warfarin was given on the evening of the surgery. Both cohorts were followed for twelve weeks after the surgery to determine if any venous thromboembolic complications had developed.

RESULTS

The nomogram cohort and the control cohort had similar daily doses of warfarin (mean, 3.2 versus 3.3 mg) and levels of international normalized ratio on postoperative day 4 (mean, 1.9 versus 1.9) (p > 0.2). The average number of days to achieve an international normalized ratio of >1.7 was 4.0 for the nomogram cohort compared with 4.3 for the control cohort (p = 0.01). The percentage of days that the international normalized ratio was between 1.8 and 2.5 was 61% for the nomogram cohort and 58% for the control cohort (p < 0.01), and the percentage of days that the international normalized ratio was >3.0 was only 6.5% for the nomogram cohort and 6.0% for the control cohort (p > 0.2). Eighty-two percent of the patients managed with the nomogram achieved an international normalized ratio of >1.7 by the time of discharge from the hospital compared with 92% in the control cohort (p = 0.01). In the three-month follow-up period, a deep-vein thrombosis or a nonfatal pulmonary embolism developed in nineteen patients (2.6%; 95% confidence interval, 1.6% to 4.0%) in the nomogram cohort compared with fourteen patients (1.4%; 95% confidence interval, 0.7% to 2.3%) in the control cohort. No major bleeding event or fatal pulmonary embolism was observed in the patients managed with use of the nomogram.

CONCLUSION

This study demonstrated that the administration of warfarin during hospitalization with use of a nomogram designed for the prevention of deep-vein thrombosis following total hip or knee arthroplasty provided effective and safe prophylaxis that was comparable with that provided by physician-adjusted dosing of warfarin.

Safety of withholding heparin in pregnant women with a history of venous thromboembolism. Recurrence of Clot in This Pregnancy Study Group

BACKGROUND

Women with a history of venous thromboembolism may be at increased risk for venous thromboembolic events during pregnancy. In these women, the decision to give or withhold heparin in the antepartum period is controversial, because accurate estimates of the frequency of recurrent thromboembolic events if antepartum heparin is withheld are not available.

METHODS

We prospectively studied 125 pregnant women with a single previous episode of venous thromboembolism. Antepartum heparin was withheld, but anticoagulant therapy was given for four to six weeks post partum. Our primary objective was to determine the rate of antepartum recurrence of venous thromboembolism. Laboratory studies were performed to identify thrombophilia in 95 women.

RESULTS

Three of the 125 women (2.4 percent) had an antepartum recurrence of venous thromboembolism (95 percent confidence interval, 0.2 to 6.9 percent). There were no recurrences in the 44 women who had no evidence of thrombophilia and who also had a previous episode of thrombosis that was associated with a temporary risk factor. Among the 51 women with abnormal laboratory results or a previous episode of idiopathic thrombosis, or both, 3 (5.9 percent) had an antepartum recurrence of venous thromboembolism (95 percent confidence interval, 1.2 to 16.2 percent).

CONCLUSIONS

The risk of recurrent antepartum venous thromboembolism in women with a history of venous thromboembolism is low, and therefore routine antepartum prophylaxis with heparin is not warranted.

Management of patients with suspected deep vein thrombosis in the emergency department: combining use of a clinical diagnosis model with D-dimer testing

The management of patients presenting to hospital Emergency Departments with suspected deep vein thrombosis is problematic since urgent diagnostic imaging is at times unavailable. We evaluated the accuracy of a rapidly available D-dimer test and the potential of combining D-dimer testing with an explicit clinical model to improve the management of patients with suspected deep vein thrombosis. Two hundred and fourteen patients with suspected deep vein thrombosis presenting to the Emergency Departments of two tertiary care institutions were enrolled in this prospective cohort study. Patients were evaluated by an Emergency Physician who determined the pre-test probability for deep vein thrombosis to be either low, moderate, or high using an explicit clinical model. Patients were managed according to their pre-test probability category by specific algorithms that in all cases included venous ultrasound imaging within 24 h and a 90-day follow-up for the development of thromboembolic complications. Patients also underwent fingerstick SimpliRED(R) whole blood agglutination D-dimer testing; however, D-dimer results did not influence subsequent patient management. D-dimer had a sensitivity of 82.5% and a specificity of 84.9% for the diagnosis of deep vein thrombosis. The observed negative predictive value of D-dimer was 96.9% (95% CI, 93.0% to 99.1%) overall, and 100% (95% CI, 96.3% to 100%) in low probability patients, 94.1% (95% CI, 83.8% to 98.8%) in moderate probability patients, and 86.7% (95% CI, 59.4% to 98.3%) in high probability patients. SimpliRED(R) D-dimer has a high negative predictive value and may be useful in excluding the diagnosis in patients at low pre-test probability for deep vein thrombosis.

Application of a diagnostic clinical model for the management of hospitalized patients with suspected deep-vein thrombosis

The purpose of this study was to evaluate whether the determination of pretest probability using a simple clinical model and the SimpliRED D-dimer could be used to improve the management of hospitalized patients with suspected deep-vein thrombosis. Consecutive hospitalized patients with suspected deep-vein thrombosis, had their pretest probability determined using a clinical model and had a SimpliRED D-dimer assay. Patients at low pretest probability underwent a single ultrasound test. A negative ultrasound excluded the diagnosis of deep-vein thrombosis whereas a positive ultrasound was confirmed by venography. Patients at moderate pretest probability with a positive ultrasound were treated for deep-vein thrombosis whereas patients with an initial negative ultrasound underwent a single follow-up ultrasound one week later. Patients at high pretest probability with a positive ultrasound were treated whereas those with negative ultrasound underwent venography. All patients were followed for three months for the development of venous thromboembolic complications. Overall, 28% (42/150), and 10% (5/50), 21% (14/71) and 76% (22/29) of the low, moderate and high pretest probability patients. respectively, had deep vein thrombosis. Two of 111 (1.8%; 95% CI = 0.02% to 6.4%) patients considered to have deep vein thrombosis excluded had events during three-month follow-up. Overall 13 of 150 (8.7%) required venography and serial testing was limited to 58 of 150 (38.7%) patients. The negative predictive value of the SimpliRED D-dimer in patients with low pretest probability was 96.2%, which is not statistically different from the negative predictive value of a negative ultrasound result in low pretest probability patients (97.8%). Management of hospitalized patients with suspected deep-vein thrombosis based on clinical probability and ultrasound of the proximal deep veins is safe and feasible.

Thrombosis in the emergency department: use of a clinical diagnosis model to safely avoid the need for urgent radiological investigation

CONTEXT

The management of patients presenting to hospital emergency departments with suspected deep vein thrombosis (DVT) is problematic because urgent diagnostic imaging capability is sometimes unavailable. Experienced physicians using clinical skills alone can classify patients with suspected DVT into low-, moderate-, and high-probability categories.

OBJECTIVES

To determine the accuracy of an explicit clinical model for the diagnosis of DVT when applied by emergency department physicians and to assess the safety and feasibility of a management strategy based on the clinical pretest probability for patients presenting to the emergency department with suspected DVT outside of regular hospital staff work hours.

METHODS

A prospective cohort study was performed in the emergency departments of 2 tertiary care institutions involving 344 patients with suspected DVT. Patient conditions were evaluated by an emergency department physician who determined the pretest probability for DVT to be low, moderate, or high using an explicit clinical model. Patients for whom DVT was considered a low pretest probability were discharged from the emergency department and returned the following day for venous compression ultrasound imaging of the affected leg. Patients for whom DVT was considered a moderate pre-test probability received a single, weight-adjusted dose of subcutaneous unfractionated heparin sodium (between 12 500 and 20 000 U), were discharged from the emergency department, and returned the next morning to undergo ultrasonography. Patients for whom DVT was considered a high pretest probability were admitted to the hospital, administered intravenous unfractionated heparin, and ultrasonography was arranged within 24 hours. Patients with positive ultrasonographic findings were diagnosed with DVT, except for those with low pretest probability for whom confirmatory venography was performed. Patients with DVT excluded in the initial evaluation period did not receive anticoagulant therapy. All patients were followed up for 90 days to monitor development of thromboembolic or bleeding complications.

RESULTS

Twenty-four (49.0% [95% confidence interval (CI), 34.5%-63.6%]) of 49 patients in the high-probability category, 15 (14.3% [95% CI, 8.3%-22.4%]) of 105 in the moderate-, and 6 (3.2% [95% CI, 1.2%-6.7%]) of 190 in the low-probability category were confirmed to have DVT. Overall, 45 (13.1%) of 344 patients were confirmed to have DVT. No patient developed pulmonary embolism or major bleeding complications within 48 hours of initial evaluation in the emergency department. Of the 301 patients who had DVT excluded during the initial evaluation period, only 2 (0.7% [95% CI, 0.1%-2.3%]) developed venous thromboembolic complications (calf vein thromboses in both) in the 3-month follow-up period.

CONCLUSIONS

Using an explicit clinical model, emergency department physicians can accurately classify patients with suspected DVT into high-, moderate-, and low-probability groups. A management plan based on probability for DVT that avoids the need for urgent diagnostic imaging is safe and feasible in the emergency department setting.

Accuracy of screening compression ultrasonography and clinical examination for the diagnosis of deep vein thrombosis after total hip or knee arthroplasty

OBJECTIVE

To determine whether compression ultrasonography or clinical examination should be considered as screening tests for the diagnosis of deep vein thrombosis (DVT) after total hip or knee arthroplasty in patients receiving warfarin prophylaxis postoperatively.

DESIGN

A prospective cohort study.

SETTING

A single tertiary care orthopedic centre.

PATIENTS

One hundred and eleven patients who underwent elective total hip or knee arthroplasty were enrolled. Postoperatively the warfarin dose was adjusted daily to maintain the international normalized ratio between 1.8 and 2.5. Eighty-six patients successfully completed the study protocol.

INTERVENTION

Before they were discharged from hospital, patients were assessed for DVT by clinical examination, bilateral compression ultrasonography of the proximal venous system and bilateral contrast venography.

RESULTS

DVT was found in 29 patients (34%; 95% confidence interval [CI] 24% to 45%), and 6 patients (7%; 95% CI 3% to 15%) had proximal DVT. DVT developed in 18 (40%) of 45 patients who underwent total knee arthroplasty and in 11 (27%) of 41 patients who underwent total hip arthroplasty. The sensitivity of compression ultrasonography for the diagnosis of proximal DVT was 83% (95% CI 36% to 99%) and the specificity was 98% (95% CI 91% to 99%). The positive predictive value of compression ultrasonography was 71%. In contrast, clinical examination for DVT had a sensitivity of 11% (95% CI 2% to 28%) and a positive predictive value of 25%.

CONCLUSIONS

DVT is a common complication after total hip or knee arthroplasty. Compression ultrasonography appears to be a relatively accurate noninvasive test for diagnosing postoperative proximal DVT. In contrast, clinical examination is a very insensitive test. Whether routine use of screening compression ultrasonography will reduce the morbidity of venous thromboembolism after joint arthroplasty requires confirmation in a prospective trial involving long-term follow-up of patients.

Value of assessment of pretest probability of deep-vein thrombosis in clinical management

BACKGROUND

When ultrasonography is used to investigate deep-vein thrombosis, serial testing is recommended for those who test negative initially. Serial testing is inconvenient for patients and costly. We aimed to assess whether the calculation of pretest probability of deep-vein thrombosis, with a simple clinical model, could be used to improve the management of patients who present with suspected deep-vein thrombosis.

METHODS

Consecutive outpatients with suspected deep-vein thrombosis had their pretest probability calculated with a clinical model. They then underwent compression ultrasound imaging of proximal veins of the legs. Patients at low pretest probability underwent a single ultrasound test. A negative ultrasound excluded the diagnosis of deep-vein thrombosis whereas a positive ultrasound was confirmed by venography. Patients at moderate pretest probability with a positive ultrasound were treated for deep-vein thrombosis whereas patients with an initial negative ultrasound underwent a single follow-up ultrasound 1 week later. Patients at high pretest probability with a positive ultrasound were treated whereas those with negative ultrasound underwent venography. All patients were followed up for 3 months for thromboembolic complications.

FINDINGS

95 (16.0%) of all 593 patients had deep-vein thrombosis; 3%, 17%, and 75% of the patients with low, moderate, and high pretest probability, respectively, had deep-vein thrombosis. Ten of 329 patients with low pretest probability had the diagnosis confirmed, nine at initial testing and one at follow-up. 32 of 193 patients with moderate pretest probability had deep-vein thrombosis, three diagnosed by the serial (1 week) test, and two during follow-up. 53 of 71 patients with high pretest probability had deep-vein thrombosis (49 by the initial ultrasound and four by venography). Only three (0.6%) of all 501 (95% CI 0.1-1.8) patients diagnosed as not having deep-vein thrombosis had events during the 3-month follow-up. Overall only 33 (5.6%) of 593 patients required venography and serial testing was limited to 166 (28%) of 593 patients.

INTERPRETATION

Management of patients with suspected deep-vein thrombosis based on clinical probability and ultrasound of the proximal deep veins is safe and feasible. Our strategy reduced the need for serial ultrasound testing and reduced the rate of false-negative or false-positive ultrasound studies.

Electrocochleographic evaluation of the guinea pig model of endolymphatic hydrops

Electrocochleography (ECochG) was used to evaluate cochlear function in guinea pigs with experimentally induced endolymphatic hydrops (ELH) before and after osmotic dehydration with either glycerol or urea. We surgically induced ELH in the right ears of 9 guinea pigs, while the right ears of 6 guinea pigs received a sham operation. The left ears of the 15 animals constituted the normal group. Eight weeks after surgery, summating potential (SP) and action potential (AP) amplitudes were measured prior to and following the administration of glycerol or urea. The SPs and SP/AP ratios were reduced in all groups, with no significant differences among groups or between dehydrating agents. Some of the hydropic ears, however, did show an increased AP threshold and a recruitment effect. In measurements from 6 additional animals, serum osmolarity increased more with urea than with glycerol. The guinea pig model remains valuable for investigation of ELH, even though it differs in significant respects from ELH in humans.

Ultrasonographic screening before hospital discharge for deep venous thrombosis after arthroplasty: the post-arthroplasty screening study. A randomized, controlled trial

BACKGROUND

The clinical significance of asymptomatic deep venous thrombosis that develops after joint arthroplasty and the value of screening tests to detect thrombi are uncertain.

OBJECTIVES

To determine 1) the rate of symptomatic deep venous thrombosis or pulmonary embolism occurring after hospitalization for joint arthroplasty and 2) the value of screening compression ultrasonography.

DESIGN

Double-blind, randomized, controlled trial.

SETTING

Tertiary care hospital.

PATIENTS

1024 patients undergoing elective total hip or knee arthroplasty who received warfarin prophylaxis.

INTERVENTION

Patients were randomly assigned to undergo either bilateral compression ultrasonography or a sham procedure before hospital discharge. Patients with a diagnosis of asymptomatic deep venous thrombosis were treated after discharge with standard anticoagulant therapy; other patients had warfarin therapy discontinued at discharge. All patients were followed for 90 days.

RESULTS

In the screening group, asymptomatic proximal deep venous thrombosis was detected in 13 of 518 patients (2.5%). Another 4 patients subsequently developed symptomatic proximal deep venous thrombosis, and 1 patient treated for asymptomatic deep venous thrombosis developed major bleeding, for a total outcome event rate of 1.0% (5 of 518 patients). In the placebo group, 3 patients developed symptomatic proximal deep venous thrombosis and 2 had nonfatal pulmonary embolism, for a total event rate of 1.0% (5 of 506 patients) (difference, 0 percentage points [95% CI, -1.2 to 1.2 percentage points]).

CONCLUSIONS

In patients undergoing total hip or knee arthroplasty, the use of warfarin prophylaxis during hospitalization results in a very low rate of symptomatic deep venous thrombosis or pulmonary embolism after hospital discharge. The use of screening compression ultrasonography at hospital discharge does not seem to be justified in this setting.

External and middle ear pathology in TGF-alpha-deficient animals

Transforming growth factor-alpha (TGF-alpha) is a growth-regulatory peptide found in a wide range of embryonic and adult tissues. TGF-alpha is produced by keratinocytes and has been reported to be overexpressed in several epidermal diseases, including middle ear cholesteatoma. This report describes ear pathology in the waved-1 mutant mouse, which is severely deficient in TGF-alpha. Morphologic changes of the external and middle ear were studied histologically in waved-1 mutants 2 weeks to 6.5 months of age. Abnormalities found in the mutants included epidermal hyperplasia of the external ear canal (EAC) and tympanic membrane (TM) and enlargement of specialized sebaceous glands adjacent to the cartilaginous EAC. Sebum and desquamated keratin progressively accumulated within the EAC, displacing the TM into the middle ear. These changes appear similar to those occurring in Mongolian gerbils, which are known to develop cholesteatoma. The alterations found in waved-1 mutants are discussed in relation to the possible involvement of TGF-alpha in cholesteatoma pathogenesis.

Inositol transport in Saccharomyces cerevisiae is regulated by transcriptional and degradative endocytic mechanisms during the growth cycle that are distinct from inositol-induced regulation

Regulation of inositol uptake activity in Saccharomyces cerevisiae during the growth cycle was examined. Activity increased as the cell population transited from lag phase to exponential growth, and continued to increase until late exponential phase. The increase in activity was due to increased transcription of the ITR1 gene and synthesis of the Itr1 permease. When the culture reached stationary phase, uptake activity decreased and dropped to a minimum within 4 h. The decrease was due to repression of ITR1 transcription, independent of the negative regulator Opi1p, and degradation of the existing permease. Degradation depended on delivery of the permease to the vacuole through the END3/END4 endocytic pathway. During exponential growth in inositol-containing medium the permease is also rapidly degraded, whereas in inositol-free medium the permease is highly stable. Rapid degradation of the permease at stationary phase occurred in inositol-free medium, indicating that there are two distinct mechanisms that trigger endocytosis and degradation in response to different physiological stimuli. In addition, the level of the enzyme required for inositol biosynthesis, inositol-1-phosphate synthase, encoded by INO1, is not reduced in stationary-phase cells, and this contrast in the regulation of inositol supply is discussed.

Low energy ion implantation in polybithiophene: microstructuring and microanalysis

Low energy ion implantation in polybithiophene (thickness 200 nm) forms a 20 nm thin modified surface layer. Combining surface analysis and electrochemical methods a non destructive depth resolved investigation of the properties of the implanted layer was performed. The composition of the modified layer is dependent on the implanted species: N causes doping, O has a sputtering effect. The modified layer acts as an electronic and ionic barrier as shown by cyclic voltammetry and electron transfer reactions. The effectivity of barrier formation is dependent on the sample pretreatment and the redox state. For reduced samples the redox charge increases for repeated voltammograms (regeneration effect). The according dose dependent band scheme shows an increasing surface resistivity for low doses. At high doses the surface resistivity decreases again due to graphitization. By application of a microstructured mask the polybithiophene was structured within a microm range. Laterally high resolving methods revealed sharp interfaces between implanted and pristine surface ranges. The doping pattern and the electronic properties are localized and do not alter even in an electrolyte. So conducting polymers can be microstructured to give stable structures with changed composition and modified electronic and ionic properties as required for microtechnological applications.

Effect of topical hyaluronic acid on experimental cholesteatoma

PURPOSE

Inflammation and connective tissue hyperplasia are believed to be important etiological factors in cholesteatoma pathogenesis. Previous work has shown that topically applied hyaluronic acid can reduce connective tissue proliferation in healing wounds and accelerate healing of tympanic membrane perforations. This study was undertaken to determine whether the antiproliferative effect of hyaluronic acid may inhibit propylene glycol-induced cholesteatoma in an animal model.

MATERIALS AND METHODS

A 60% propylene glycol solution was injected bilaterally into the middle ear cavities of 20 adult chinchillas. The control group (N = 10) received propylene glycol alone. In addition to propylene glycol injections, the experimental group (N = 10) received repeated bilateral topical applications of 1.5% hyaluronic acid onto the tympanic membranes. Animals were killed at 4 weeks for gross and light microscopic examination.

RESULTS

Seven control and 10 experimental animals survived the full 1-month study period. At the end of that time, cholesteatoma was found in 71% (10/14) of control ears and 70% (14/20) of experimental ears. Tympanic membrane structure did not differ significantly between groups by light microscopy and, in all animals, cholesteatomas originated by migration of hyperplastic epidermis through the tympanic membrane, as has been observed in previous studies using this animal model.

CONCLUSION

Under the conditions of this study, topical hyaluronic acid had no significant effect on cholesteatoma formation.

The effect of cyclophosphamide on development of experimental cholesteatoma

BACKGROUND

Recent work has shown that middle ear application of propylene glycol in chinchillas produces an inflammatory reaction resulting in cholesteatoma formation in 50% to 70% of animals. This study was done to determine if cyclophosphamide, an immune suppressor and anti-inflammatory agent, is capable of inhibiting cholesteatoma development in the animal model.

METHODS

Ten adult chinchillas received systemic cyclophosphamide (20 mg/kg per day) for 14 days. On days 5, 8, and 11 of that period, the animals also received bilateral middle ear applications of 60% propylene glycol (0.2 mL per ear). Four weeks after the first propylene glycol application, the animals were killed for histologic evaluation.

RESULTS

Eight of the 10 animals survived the full 4-week study period, providing 16 temporal bones for evaluation. It was found that cyclophosphamide reduced the leukocyte counts; however, middle ear inflammation appeared unaffected. Cholesteatoma occurred in eight (50%) of the 16 ears studied, and histologic findings were essentially identical to those previously seen in animals given propylene glycol alone.

CONCLUSION

Under the conditions of this study, cyclophosphamide had no effect on cholesteatoma development in the animal model.

A regional autologous bone marrow transplant network: transfers to designated centers on the day after transplant

Autologous bone marrow transplantation (ABMT) is becoming increasingly prevalent for treatment of advanced malignant disease. In order to increase the availability and utility of this therapy, we assessed the feasibility of transferring patients to their regional referral centers on the day after marrow infusion (day 1), for management post-transplant. This prospective study compares the outcome of 77 patients either transferred the day after marrow transplant for subsequent management at one of six selected Canadian regional centers closest to their domicile, or treated entirely at The Toronto Hospital, according to a common protocol. Study end-points included frequency of complications during transfer, transplant-related morbidity and mortality and hematopoietic recovery. Assessment of eligibility for transplant, bone marrow harvesting, autograft cryopreservation, administration of intensive therapy and marrow infusion were conducted in all cases at The Toronto Hospital. Thirty patients received marrow transplants and were transferred on day 1. There were no complications during transfer. Compared with 47 consecutive patients treated entirely at The Toronto Hospital, there were no differences in treatment-related morbidity or mortality, use of intravenous antifungal therapy or total days of hospitalization. We conclude that day 1 transfer of patients after ABMT to designated centers is feasible and safe. The operation of a regional ABMT network appears to benefit patients, relatives, referring physicians, the transplant center and may also improve health care delivery.

Cochlear permeability of neomycin and gentamicin: an immunohistochemical study

Aminoglycoside antibiotics (AGAs) target specifically the cochleo-vestibular hair cells, but with varied ototoxicity. Differences in their penetration and clearance rates into the membranous labyrinth may play a role. This in turn may be related to a difference in the number of amine groups, the cationic nature, as well as the molecular weight and size of the AGA molecule. Immunohistochemical labeling techniques were used to study the pathways of gentamicin and neomycin from the perilymph into cochlear tissues and target cells. The more cochleotoxic AGA, neomycin, penetrated into cochlear tissues faster than the less cochleotoxic AGA, gentamicin.

Effects on cochlear morphology of repeated insults to the stria vascularis

The interrelationship of stria vascularis and organ of Corti integrity was investigated. Strial morphology was altered by repeated injections of ethacrynic acid in the chinchilla. Although prolonged temporary strial damage was created, neither strial atrophy nor organ of Corti damage resulted.

Dependence of the bilayer to hexagonal phase transition on amphiphile chain length

Several series of amphiphiles of increasing chain length were tested for their abilities to modify the L alpha-HII transition of dielaidoylphosphatidylethanolamine using differential scanning calorimetry. Acylcarnitines, alkyl sulfates, alkylsulfobetaines, and phosphatidylcholines, with chain lengths between about 6 and 12 carbon atoms, show an increasing capacity to raise the L alpha-HII phase transition temperature of phosphatidylethanolamine. This is ascribed to increased partitioning of the added amphiphile from water into the membrane as the chain length increases. Alkyl sulfates and alkyltrimethylammonium bromides have diminished capacities to raise the L alpha-HII transition temperature as the chain length is increased from 12 to 16. This is caused by an increase in the hydrophobic portion of the amphiphile leading to a change in the intrinsic radius of curvature and a decrease in the hydrocarbon packing constraints in the HII phase relative to the shorter chain amphiphiles. The L alpha-HII transition temperature of phosphatidylethanolamine with acylcarnitines of chain length 14-20 carbon atoms, alkylsulfobetaines above 14 carbon atoms, and phosphatidylcholines with acyl groups having above 10 carbon atoms is relatively insensitive to chain length. We suggest that this is caused by a balance between increasing hydrocarbon volume promoting the HII phase through decreased intrinsic radius of curvature and greater relief of hydrocarbon packing constraints vs greater intermolecular interactions favoring the more condensed L alpha phase. This latter effect is more important for amphiphiles with large headgroups which can pack more efficiently in the L alpha phase. The phosphatidylcholines show a gradual decrease in bilayer stabilization between 10 and 22 carbon atoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Cochlear vessel permeability to horseradish peroxidase after diuretic administration in the chinchilla

The permeability of strial vessels to the small protein, HRP, was examined after administration of diuretics to determine if increased vascular permeability is a factor in the development of strial edema as it is in acoustic trauma. Chinchillas were injected with HRP and either ethacrynic acid, a loop-inhibiting diuretic, or mannitol, an osmotic diuretic. There was no increased vascular permeability to HRP. Therefore, unlike the increased vessel permeability of HRP seen after an acoustic insult, increased vessel permeability of HRP is not a factor in the formation of strial edema after either mannitol or ethacrynic acid administration.

Local vs systemic effects of acoustic trauma on cochlear structure and transport

Whether certain effects of acoustic trauma on cochlear structure and function were due to local or systemic agents was investigated in the chinchilla. After unilateral ossicular disarticulation, the animals were given a noise exposure known to cause cochlear damage and vessel transport changes in the stria vascularis. The cochleas with disarticulated ossicular chains received an effective exposure well below one that causes pathologic damage. Only the cochleas with intact ossicular chains showed an increase in the permeability of the strial vessels to horseradish peroxidase tracer and manifested strial edema and organ of Corti damage. These results indicate that the effects of acoustic trauma on cochlear structure and strial vessel transport are induced locally, not systemically. In addition, the minimum time of exposure to 120-dB, 700- to 2800-Hz noise that causes massive cochlear damage in the chinchilla was shown to be between five and ten minutes.

Effects of prenatal nitrofen exposure on cardiac structure and function in the rat

The herbicide nitrofen was administered to pregnant Fischer-344 and Sprague-Dawley rats on Days 10-13 of gestation (po, 20 or 40 mg/kg daily) and its effects on cardiac structure and function were investigated in the offspring. In the 21-day fetuses, nitrofen did not influence intrauterine growth or basal heart rate. In contrast, the herbicide produced a marked depression of heart rate and abnormal electrocardiographic (ECG) profiles in the newborn rats, in conjunction with labored respiratory movements and a profound increase in postnatal mortality. A few animals displayed cardiac ventricular septal defects and diaphragmatic hernias but these malformations did not appear to be associated with the ECG changes. The chronotropic deficiencies seen in the nitrofen-treated pups were reversible by acute hyperoxia (40% oxygen). These results suggest that the teratogenic effects of nitrofen on cardiac physiology and on postnatal mortality cannot be accounted for solely by specific gross anatomical damages to the rat heart and diaphragm; rather, other more subtle morphological and physiological factors which contribute to improper systemic delivery and cellular utilization of oxygen may be involved.

A computer-assisted electrocardiographic analysis system: methodology and potential application to cardiovascular toxicology

An automated analysis of electrocardiographic (ECG) waveforms, based on a precise one-dimensional analysis of features within a generalized computer-enhanced ECG waveform, has been developed in our laboratory. ECG signals are monitored, amplified, and recorded using standard techniques. The recorder output signal is distributed to a microcomputer system. Software developed for the microcomputer slows the signal playback rate and permits operator review of the slowed signal for arrhythmia analysis. The analysis program identifies and superimposes 10-40 individual ECG complexes, depending on the heart rate, and generates an "ensembled" waveform. Operator interaction permits delineation of specific points on the displayed waveform and calculation of heart rate and duration of components within the ECG complex. The primary advantages of this system include (1) extensive automation--computer support decreases analytical time, increases precision, and permits rapid screening of large numbers of animals; (2) enhanced sensitivity--the use of functional parameters should provide a more sensitive index of toxicity than morphological parameters; (3) broad utility--this system provides the capability to utilize a variety of animals, both anesthetized and unanesthetized, ranging in age from fetuses to geriatrics, and permits studies of block as well as longitudinal design; and (4) ease of replication--standardization of equipment and techniques facilitates replication by other laboratories.

Electrocardiographic responses of rat fetuses with clamped or intact umbilical cords to acute maternal uterine ischemia

Uterine ischemia results in severe cardiac disturbances in the fetus. It has been postulated that these effects are due to interaction between the fetus and the ischemic uterus or placenta, and not to hypoxia or buildup of metabolites in the fetus. Rat fetal cardiac responses to uterine clamping and umbilical cord clamping were compared by electrocardiography. On day 21 of gestation, fetuses in a total of 14 pregnant rats were exposed to umbilical clamping, uterine clamping, or no clamping. Electrocardiograms were recorded for each fetus immediately after clamping and at 10, 20, and 30 minutes after clamping. Immediately after clamping, the uterine clamping group alone showed severe sinus bradycardia. At all other observation times, fetuses exposed to uterine or umbilical clamping showed bradycardia and other electrocardiographic changes typically associated with hypoxia. Therefore, umbilical clamping protected the fetuses from the adverse effects of uterine clamping for only a very short time.

Multigeneration study of 1,2,4-trichlorobenzene in rats

Rats were continuously exposed to 0, 25, 100, or 400 ppm 1,2,4-trichlorobenzene (TCB) in the drinking water, beginning with birth of the F0 generation and continuing through weaning of the F2 generation. The treatment did not affect fertility, growth, viability, locomotor activity, or blood chemical analysis. Adrenal gland enlargement was observed in both the F0 and F1 animals at 95 d of age. To further examine the adrenal enlargement found in the reproduction study, an acute toxicity study was undertaken in which immature females were given ip injections of 0, 250, or 500 mg/kg TCB on 3 consecutive days. It was found that TCB had no estrogenic activity and that the livers and adrenals of treated females were significantly larger than those of controls. Rather than being estrogenic, TCB in this treatment regimen resulted in a decrease in uterine weight. These two studies demonstrate that chronic or acute doses of TCB can produce adrenal enlargement in rats.