Closed Toggle Pinning for Canine Traumatic Coxofemoral Luxation

A method of closed implantation of a toggle pin bone anchor and prosthetic ligament was developed for the treatment of traumatic canine coxofemoral luxation. Radiographic and anatomical evaluation of the canine femur and acetabulum were performed in order to develop an imaging and instrumentation technique that would allow closed placement of a toggle pin bone anchor under fluoroscopic guidance, while at the same time minimizing, or eliminating, damage to the articular cartilage. The surgical technique was then performed in 14 canine cadaver coxofemoral joints, followed by gross evaluation of implant placement, and potential cartilage or soft tissue damage. The cervical canal radiographic view of the proximal femur allowed placement of the drill hole through the fovea capitis of the femoral head without damaging the articular cartilage. The acetabular fossa was readily distinguishable from the acetabular articular cartilage on both of the lateral and ventrodorsal radiographic views of the pelvis. The toggle pin apparatus was inserted without damage to the articular cartilage in nine out of the fourteen hips and the bone tunnels were situated within the cancellous bone of the femoral neck in each of the nine specimens evaluated. Complications encountered during the procedure included bending and/or breakage of the guide wire in three hips and damage to the articular cartilage in two hips. The success of technique modifications designed to diminish the incidence of these complications awaits investigation in a clinical trial. Closed toggle pinning for canine traumatic coxofemoral luxation has the potential advantage of achieving rapid stabilization of the coxofemoral joint without damage to the articular cartilage and the need for an open approach to the joint. The clinical application of the technique is reported in one patient.

The equipment and methodology for closed implantation of a toggle pin bone anchor and prosthetic ligament was developed for the treatment of traumatic coxofemoral luxation. A cadaver study was performed to assess the viability of the technique. Clinical application in one case is described.

Accelerated total dose infusion of low molecular weight iron dextran is safe and efficacious in chronic kidney disease patients

BACKGROUND

Low molecular weight iron dextran (LMWID) is licensed for use as a total dose infusion (TDI) over 4-6 h. In order to improve patient convenience and cost-effectiveness of therapy, we investigated the safety and efficacy of adopting accelerated dosing regimens and compared this with a standard rate LMWID infusion.

METHODS

A retrospective study of patients undergoing accelerated and standard rate TDI of LMWID was conducted across three centres. A total of 1904 doses of LMWID were administered at an accelerated rate of 1 g over 1 h 40 min. This was compared with 395 patients who had standard rate infusion of 1 g LMWID over 3-4 h.

RESULTS

There were eight minor adverse events in patients receiving accelerated dose LMWID (8/1904, 0.42%) in comparison to one adverse event in patients receiving a standard regimen (1/395, 0.25%). No serious adverse events occurred. Serum haemoglobin and ferritin significantly improved in both groups.

CONCLUSION

TDI LMWID is a safe and efficacious method of iron replacement. Accelerated infusion regimen is safe and compares well with standard rate infusion regimen. Furthermore, accelerated TDI of LMWID enables greater numbers of patients to be treated and consequently there appear to be advantages for both patient and health resources.

Residence time and contact volume in sloped compost and compost/vegetated filter beds

Little is known about transport mechanisms in sloped dormant vegetated and compost only filters for roadway runoff. Residence time experiments were carried out in triplicate in 0.254 m wide × 0.65 m long by 0.10 m deep beds using a bromide tracer. Bed slope was 12°. Only at the lowest flow rate tested (0.276 l/min per m of filter width) were mean residence times in compost beds with and without dormant grasses different. Pools formed ahead of beds at higher flow rate, and pool depth reached bed depth at 3.54 l/min/m. The ideal model of a well-mixed pool in series with a plug flow porous bed was a good predictor of effluent concentration data at flows ≥2.66 l/min/m. Theoretical contact volume within the beds increased with flow rate to reach approx. 30% of available pore space, while free drainage volume declined. Data shows that designs for sloped compost filter beds must consider flow, bed depth and length, and whether or not areas for pooling are needed.

Endogenous endophthalmitis: 10-year experience at a tertiary referral centre

PURPOSE

Endogenous endophthalmitis (EE) is a sight-threatening emergency and the aetiology is often multifactorial. Delayed diagnosis may exacerbate the poor visual prognosis. We describe the management and visual outcomes of EE presenting to a tertiary referral centre.

PATIENTS AND METHODS

A prospective consecutive case series of 64 patients presenting with presumed EE from 1997 to 2007 to the Royal Victorian Eye and Ear Hospital were included. All data were collected in a standardized manner. Outcome measures included: visual acuity, microbial profiles, and vitrectomy rate.

RESULTS

In total, 64 cases of EE were identified over the study period with a mean age of 57.5 years, and 53.5% were male. Presenting acuities ranged from Snellen 6/6 to no perception of light (NPL). Identifiable risk factors were present in 78.1%, with the majority related to intravenous drug abuse. A 64.1% culture positivity rate was recorded. A vitrectomy rate of 57, 56, and 21% was recorded in documented bacterial, fungal, and no growth cases, respectively. Final Snellen acuities ranged from 6/6 to NPL. A total of 5 out of 64 eyes were enucleated, of which 3 identified Klebsiella species. Better visual outcome was documented in fungal cases.

CONCLUSION

EE is a serious ocular condition and has a varied aetiology. Visual outcomes are often poor, irrespective of the method of management. Fungal aetiology often confers a better prognosis, and vitrectomy is advocated for bacterial proven cases.

Complete hydatidiform mole in Hawaii: An epidemiological study

An analysis of hydatidiform moles occurring in Hawaii over a 14-year period (1968-1981) was undertaken. The pathology of all 278 reported molar pregnancies was reviewed and showed 69.4% to be complete, 24.5% to be partial, and 6.1% to be nonmolar. A case-control epidemiological investigation of the complete moles showed maternal age and race to be important, moles being significantly more prevalent in women under 20 and over 40 yr of age and also in women of Japanese, Filipino, and other Oriental ancestry. However no difference was seen in the prevalence of moles between Oriental women born in the Orient and those born and raised in Hawaii. No significant difference was found in paternal age, paternal race, socioeconomic status, or reproductive history, suggesting that these factors do not play an important role in the etiology of complete hydatidiform mole. Incidence rates for complete moles were calculated taking age and race into consideration and ranged from a high of 1 in 150 to a low of 1 in 2,000 naturally terminating pregnancies.

A Java application for tissue section image analysis

The medical industry has taken advantage of Java and Java technologies over the past few years, in large part due to the language's platform-independence and object-oriented structure. As such, Java provides powerful and effective tools for developing tissue section analysis software. The background and execution of this development are discussed in this publication. Object-oriented structure allows for the creation of "Slide", "Unit", and "Cell" objects to simulate the corresponding real-world objects. Different functions may then be created to perform various tasks on these objects, thus facilitating the development of the software package as a whole. At the current time, substantial parts of the initially planned functionality have been implemented. Getafics 1.0 is fully operational and currently supports a variety of research projects; however, there are certain features of the software that currently introduce unnecessary complexity and inefficiency. In the future, we hope to include features that obviate these problems.

Supportive care management of brain metastases: what is known and what we need to know. Conference proceedings of the National Cancer Institute of Canada (NCIC) Workshop on Symptom Control in Radiation Oncology

OBJECTIVES

To review the results of published randomised controlled trials in the treatment of brain metastases and, from the knowledge gained from these trials, to identify potential study questions.

MATERIALS AND METHODS

The literature was searched for randomised controlled trials that dealt with the management of brain metastases. Potential research questions were identified on the basis of the results of the literature review.

RESULTS

A number of research questions were identified. In the context of the NCIC Symptom Control Group, a trial of supportive care alone vs supportive care and whole-brain radiotherapy (WBRT) in a subset of patients with the diagnosis of brain metastases was deemed to be of highest priority. We discussed a number of issues relating to the feasibility of such a trial.

CONCLUSIONS

The optimal management of brain metastases remains elusive. Despite the results of numerous randomised controlled trials, many questions remain unanswered. The magnitude of benefit using WBRT above supportive care alone is uncertain. A trial of supportive care alone vs supportive care and WBRT may be successful once target population, feasibility and methodological issues are thoroughly solved.

Generating mouse models of retinal disease using ENU mutagenesis

We used the chemical mutagen, N-ethyl-N-nitrosourea, to induce random point mutations in the germline of the mouse strain C57BL/6 in order to generate models of retinal diseases. 1163 mutagenised first generation mice produced using this approach were examined for eye abnormalities. Approximately one-third (412) presented with some form of ocular abnormality. Most changes were unilateral and confined to the anterior segment of the eye. Less than 10% (44) of identified changes affected the posterior segment of the eye. 21 mice with varying ocular abnormalities, including 17 with retinal changes, were bred to produce second generation mice to confirm genetic inheritance. Genetic inheritance was confirmed in several of these lines including three with retinal changes.

Safety of intra-arterial thrombolysis in the postoperative period

BACKGROUND AND PURPOSE

Limited systemic fibrinolysis and reduced dosage are features of intra-arterial thrombolyis (IAT) that may be advantageous in the treatment of postoperative strokes. However, IAT may increase the risk of surgical bleeding. We sought to determine the safety of postoperative IAT.

METHODS

This was a retrospective case series from 6 university hospitals. All cases of IAT within 2 weeks of surgery were identified. Demographics, stroke mechanism, stroke severity, imaging and angiographic findings, time between surgery and lysis, thrombolytic agent used, surgical site bleeding, intracranial bleeding, and mortality rates were determined. Death or complications directly related to IAT were determined.

RESULTS

Thirty-six patients (median age, 71.5 years; range, 45 to 85) were identified. Median time from surgery to stroke was 21.5 hours (range, 1 to 120). Open heart surgery was done in 18 (50%), carotid endarterectomy in 6 (17%), craniotomy in 3 (8%), ophthalmologic-ear, nose and throat surgery in 2 (6%), urologic-gynecologic surgery in 4 (11%), orthopedic surgery in 2 (6%), and plastic surgery in 1 (3%). The stroke causes were cardioembolism in 24 (67%), large-vessel atherosclerosis in 4 (11%), dissection in 3 (8%), postendarterectomy occlusion in 4 (11%), and radiation arteriopathy in 1 (3%). Median time to angiogram was 2.5 hours (0.1 to 5.5). Occlusion sites were M1 in 19 (53%), M2 in 9 (25%), internal carotid artery in 5 (14%), basilar artery in 2 (6%), and posterior communicating artery in 1 (3%). Thrombolysis was completed at a median of 4.5 hours (range, 1 to 8.0). Tissue plasminogen activator was used in 19 (53%) and urokinase in 17 (47%). Nine (26%) patients died. Surgical site bleeding occurred in 9 (25%) cases (minor in 6, major in 3). The major surgical bleeds were 2 post-craniotomy intracranial hemorrhages and 1 hemopericardium after coronary artery bypass grafting; all were fatal. Six deaths were non-IAT related: 3 caused by cerebral edema and 3 by systemic causes. Major bleeding complications were significantly more common among patients with craniotomy (P<0.02).

CONCLUSIONS

Postoperative IAT carries a risk of bleeding in up to 25% of patients but is usually minor surgical site bleeding. Avoiding IAT in intracranial surgery patients may reduce complications. Mortality rate in this series was similar to that reported in prior IAT trials. IAT remains a viable therapeutic option for postoperative strokes.

A high-resolution map of human chromosome 12

Our sequence-tagged site-content map of chromosome 12 is now integrated with the whole-genome fingerprinting effort. It provides accurate and nearly complete bacterial clone coverage of chromosome 12. We propose that this integrated mapping protocol serves as a model for constructing physical maps for entire genomes.

Identification of 6 new mutations in the iduronate sulfatase gene. Mutation in brief no. 233. Online

Mucopolysaccharidosis type II (Hunter syndrome) is an X-linked lysosomal storage disorder caused by a deficiency of the enzyme iduronate-2-sulfatase. We sequenced genomic DNA and RT-PCR products in the iduronate sulfatase (IDS) gene in 6 unrelated patients with Hunter syndrome to assess genotype/phenotype relationships and offer carrier testing where required. Six novel mutations were identified: four missense mutations, one four-base pair deletion (596-599delAACA) and a cryptic splice site mutation. Three of the missense mutations were significant amino acid substitutions (S143F, S491F, E341K) of which the latter two involve amino acids conserved amongst sulfatase enzymes. The patients identified with these mutations all had a severe clinical phenotype. One missense mutation with a minimal amino acid substitution (H342Y), in a non-conserved region of the gene, was associated with a mild clinical phenotype. We identified a novel cryptic splice site (IVS5+934G>A) with some normal (wild type) mRNA processing. We predict that the normal mRNA product confered some residual functional enzyme, resulting in a mild phenotype associated with the absence of overt central nervous system disease.

Interaction of antioxidants and their implication in genetic anemia

The generation of reactive oxygen species (ROS) is a steady-state cellular event in respiring cells. Their production can be grossly amplified in response to a variety of pathophysiological conditions such as inflammation, immunologic disorders, hypoxia, hyperoxia, metabolism of drug or alcohol, exposure to UV or therapeutic radiation, and deficiency in antioxidant vitamins. Uncontrolled production of ROS often leads to damage of cellular macromolecules (DNA, protein, and lipids) and other small antioxidant molecules. A number of major cellular defense mechanisms exist to neutralize and combat the damaging effects of these reactive substances. The enzymic system functions by direct or sequential removal of ROS (superoxide dismutase, catalase, and glutathione peroxidase), thereby terminating their activities. Metal binding proteins, targeted to bind iron and copper ions, ensure that these Fenton metals are cryptic. Nonenzymic defense consists of scavenging molecules that are endogenously produced (GSH, ubiquinols, uric acid) or those derived from the diet (vitamins C and E, lipoic acid, selenium, riboflavin, zinc, and the carotenoids). These antioxidant nutrients occupy distinct cellular compartments and among them, there are active recycling. For example, oxidized vitamin E (tocopheroxy radical) has been shown to be regenerated by ascorbate, GSH, lipoic acid, or ubiquinols. GSH disulfides (GSSG) can be regenerated by GSSG reductase (a riboflavin-dependent protein), and enzymic pathways have been identified for the recycling of ascorbate radical and dehydroascorbate. The electrons that are used to fuel these recycling reactions (NADH and NADPH) are ultimately derived from the oxidation of foods. Sickle cell anemia, thalassemia, and glucose-6-phosphate-dehydrogenase deficiency are all hereditary disorders with higher potential for oxidative damage due to chronic redox imbalance in red cells that often results in clinical manifestation of mild to serve hemolysis in patients with these disorders. The release of hemoglobin during hemolysis and the subsequent therapeutic transfusion in some cases lead to systemic iron overloading that further potentiates the generation of ROS. Antioxidant status in anemia will be examined, and the potential application of antioxidant treatment as an adjunct therapy under these conditions will be discussed.

Interaction of antioxidants and their implication in genetic anemia

The generation of reactive oxygen species (ROS) is a steady-state cellular event in respiring cells. Their production can be grossly amplified in response to a variety of pathophysiological conditions such as inflammation, immunologic disorders, hypoxia, hyperoxia, metabolism of drug or alcohol, exposure to UV or therapeutic radiation, and deficiency in antioxidant vitamins. Uncontrolled production of ROS often leads to damage of cellular macromolecules (DNA, protein, and lipids) and other small antioxidant molecules. A number of major cellular defense mechanisms exist to neutralize and combat the damaging effects of these reactive substances. The enzymic system functions by direct or sequential removal of ROS (superoxide dismutase, catalase, and glutathione peroxidase), thereby terminating their activities. Metal binding proteins, targeted to bind iron and copper ions, ensure that these Fenton metals are cryptic. Nonenzymic defense consists of scavenging molecules that are endogenously produced (GSH, ubiquinols, uric acid) or those derived from the diet (vitamins C and E, lipoic acid, selenium, riboflavin, zinc, and the carotenoids). These antioxidant nutrients occupy distinct cellular compartments and among them, there are active recycling. For example, oxidized vitamin E (tocopheroxy radical) has been shown to be regenerated by ascorbate, GSH, lipoic acid, or ubiquinols. GSH disulfides (GSSG) can be regenerated by GSSG reductase (a riboflavin-dependent protein), and enzymic pathways have been identified for the recycling of ascorbate radical and dehydroascorbate. The electrons that are used to fuel these recycling reactions (NADH and NADPH) are ultimately derived from the oxidation of foods. Sickle cell anemia, thalassemia, and glucose-6-phosphate-dehydrogenase deficiency are all hereditary disorders with higher potential for oxidative damage due to chronic redox imbalance in red cells that often results in clinical manifestation of mild to serve hemolysis in patients with these disorders. The release of hemoglobin during hemolysis and the subsequent therapeutic transfusion in some cases lead to systemic iron overloading that further potentiates the generation of ROS. Antioxidant status in anemia will be examined, and the potential application of antioxidant treatment as an adjunct therapy under these conditions will be discussed.

Agreement and variability in the interpretation of early CT changes in stroke patients qualifying for intravenous rtPA therapy

BACKGROUND AND PURPOSE

Ischemic changes identified on CT scans performed in the first few hours after stroke onset, which are thought to possibly represent early cytotoxic edema and development of irreversible injury, may have important implications for subsequent treatment. However, insecurity and conflicting data exist over the ability of clinicians to correctly recognize and interpret these changes. We performed a detailed review of selected baseline CT scans from the NINDS rt-PA Stroke Trial to test agreement among experienced stroke specialists and other physicians on the presence of early CT ischemic changes.

METHODS

Seventy baseline CT scans from the NINDS Stroke Trial were read and classified for the presence or absence of various early findings of ischemia by 16 individuals, including NINDS trial investigators, other neurologists, other emergency medicine physicians, and radiology or stroke fellows. CT scans included normal scans and scans from patients who later developed symptomatic intracranial hemorrhage, as well as scans on which the NINDS rt-PA Stroke Trial neuroradiologist identified clear-cut early CT changes. For each CT finding, kappa-statistics were used to assess the proportion of agreement beyond chance.

RESULTS

kappa-Values (95% confidence interval [CI]) ranged from 0.20 (-0.20, 0.61) (fair agreement) to 0.41 (0.37, 0.45) (moderate agreement) among the 16 viewers, and the kappa-value was only 0.39 (0.29, 0.49) (fair) in answer to the question "do early CT changes involve more than one third of the MCA [middle cerebral artery] territory?" There was substantial variability within each specialty group and between groups. kappa-Values were only fair to moderate even among physicians experienced in selecting and treating acute stroke patients with rtPA. Observed agreement ranged from 68% to 85%. Physicians agreed on the finding of early CT changes involving >33% of the MCA territory 77% of the time, although the kappa-value of 0.39 suggested only moderate agreement beyond chance.

CONCLUSIONS

There is considerable lack of agreement, even among experienced clinicians, in recognizing and quantifying early CT changes. Improved methods of recognizing and quantifying early ischemic brain damage are needed.

Orthostatic hypotension predicts mortality in elderly men: the Honolulu Heart Program

BACKGROUND

Population-based data are unavailable concerning the predictive value of orthostatic hypotension on mortality in ambulatory elderly patients, particularly minority groups.

METHODS AND RESULTS

With the use of data from the Honolulu Heart Program's fourth examination (1991 to 1993), orthostatic hypotension was assessed in relation to subsequent 4-year all-cause mortality among a cohort of 3522 Japanese American men 71 to 93 years old. Blood pressure was measured in the supine position and after 3 minutes of standing, with the use of standardized methods. Orthostatic hypotension was defined as a drop in systolic blood pressure (SBP) of >/=20 mm Hg or in diastolic blood pressure of >/=10 mm Hg. Overall prevalence of orthostatic hypotension was 6.9% and increased with age. There was a total of 473 deaths in the cohort over 4 years; of those who died, 52 had orthostatic hypotension. Four-year age-adjusted mortality rates in those with and without orthostatic hypotension were 56.6 and 38.6 per 1000 person-years, respectively. With the use of Cox proportional hazards models, after adjustment for age, smoking, diabetes mellitus, body mass index, physical activity, seated systolic blood pressure, antihypertensive medications, hematocrit, alcohol intake, and prevalent stroke, coronary heart disease and cancer, orthostatic hypotension was a significant independent predictor of 4-year all-cause mortality (relative risk 1.64, 95% CI 1.19 to 2.26). There was a significant linear association between change in systolic blood pressure from supine position to standing and 4-year mortality rates (test for linear trend, P<0.001), suggesting a dose-response relation.

CONCLUSIONS

Orthostatic hypotension is relatively uncommon, may be a marker for physical frailty, and is a significant independent predictor of 4-year all-cause mortality in this cohort of elderly ambulatory men.

Sibling HLA-matched cord blood transplant for beta-thalassemia: report of two cases, expression of fetal hemoglobin, and review of the literature

PURPOSE

A program of cord blood stem cell (CBSC) transplants for patients with beta-thalassemia major was initiated in conjunction with the prenatal diagnostic service in 1994. Two patients who received HLA-matched related CBSC transplants with posttransplant fetal hemoglobin (HbF) expression are described and the literature is reviewed.

PATIENTS AND METHODS

After screening 12 pregnancies, matched sibling CBSC transplants were performed for 2 girls with beta-thalassemia major when they were 3.8 and 2.2 years old, respectively. Their HbF was assayed serially.

RESULTS

The nucleated cell counts/kg were 11.4 x 10(7) and 6.2 x 10(7), which engrafted on days 19 and 24, respectively. The children are now transfusion-independent at 3 years and 1.2 years posttransplant. Their HbF levels showed a rapid rise posttransplant and reached peak levels of 37.2% and 42.2% on day 83 and day 88, respectively. The HbF levels declined to 1.0% and 3.8% on day 581 and day 305, respectively. Nine other sibling CBSC transplants for thalassemias have been reported with an engraftment rate of approximately 50%. Graft rejection was related to insufficient CBSC number in one.

CONCLUSIONS

HbF levels in patients with beta-thalassemia major after CBSC transplants could be influenced by many factors, including reactivation of HbF synthesis, intrinsic rate of Hb switching of CBSC, and mixed chimerism.

Clinical features of moyamoya disease in the United States

BACKGROUND AND PURPOSE

We report the clinical features and longitudinal outcome of the largest cohort of patients with moyamoya disease described from a single institution in the western hemisphere. Moyamoya disease in Asia usually presents with ischemic stroke in children and intracranial hemorrhage in adults.

METHODS

Our study population included all patients with moyamoya disease evaluated at a university hospital in Houston, Texas from 1985 through 1995 (n = 35). We used Kaplan-Meier methods to estimate individual and hemispheric stroke risk by treatment status (medical versus surgical). Predictors of neurological outcome were assessed.

RESULTS

The ethnic background of our patients was representative of the general population in Texas. The mean age at diagnosis was 32 years (range, 6 to 59 years). Ischemic stroke or transient ischemic attack was the predominant initial symptom in both adults and children. Of the 6 patients with intracranial hemorrhage, 5 had an intraventricular site of hemorrhage. The crude stroke recurrence rate was 10.3% per year in 116 patient-years of follow-up. Twenty patients underwent surgical revascularization, the most common procedure being encephaloduroarteriosynangiosis. The 5-year risk of ipsilateral stroke after synangiosis was 15%, compared with 20% for medical treatment and 22% overall for surgery.

CONCLUSIONS

Our observations indicate that moyamoya disease may have a different clinical expression in the United States than in Asia, and may demonstrate a trend toward a lower stroke recurrence rate and better functional outcome after synangiosis.

Primary human herpes virus 6 infection transmitted from donor to recipient through bone marrow infusion

An 8.5-month-old boy with Wiskott-Aldrich syndrome received a sibling matched bone marrow transplant from his healthy non-identical twin brother. The donor had primary human herpes virus 6 (HHV-6) infection around the time of bone marrow donation. The recipient had hepatitis in the first week and then developed fever and rash on day 18. Skin biopsy was shown to have HHV-6 antigen and his peripheral blood leukocytes were HHV-6 DNA positive. He engrafted on day 18 but the ANC dropped from 5.5 x 10(9)/l (day 23) to 0.48 x 10(9)/l (day 34) with persistent HHV-6 DNAemia. Bone marrow on day 35 was positive for HHV-6 DNA. He was treated with G-CSF and ganciclovir with good response. He later had pneumonitis which was treated empirically with foscarnet, ceftazidime and clarithromycin.

Intravenous tissue plasminogen activator for acute ischemic stroke: feasibility, safety, and efficacy in the first year of clinical practice

BACKGROUND AND PURPOSE

The feasibility, safety, and efficacy of intravenous tissue plasminogen activator (t-PA) for patients with acute ischemic stroke in clinical practice need to be assessed.

METHODS

We initiated a prospective open-label study at a university hospital and two community hospitals in Houston, Tex, immediately after the publication of the National Institute of Neurological Disorders and Stroke (NINDS) t-PA study. A total of 30 patients, age 32 to 90 years, were treated with 0.9 mg/kg of intravenous t-PA (maximum dose, 90 mg) within 3 hours of acute ischemic stroke between December 1995 and December 1996.

RESULTS

Six percent (6%) of all patients hospitalized with ischemic stroke received intravenous t-PA at the university hospital and 1.1% at the community hospitals. The rates of total, symptomatic, and fatal intracerebral hemorrhage were 10%, 7%, and 3%. Thirty-seven percent (37%) of patients recovered to fully independent function. The average time from stroke onset to emergency department arrival was 57 minutes; emergency department arrival to computed tomography scan 41 minutes; and computed tomography scan to administration of treatment 59 minutes.

CONCLUSIONS

When treatment guidelines are carefully followed in an urban hospital setting, intravenous t-PA for acute ischemic stroke is feasible and shows safety and efficacy comparable to the results of the NINDS study.

T cell development in mice expressing splice variants of the protein tyrosine phosphatase CD45

The transmembrane protein tyrosine phosphatase CD45 is expressed in multiple isoforms as a result of alternative splicing of variable exons encoding the extracellular domain. CD45 expression is critical for T cell development, and thymocyte maturation is blocked at the immature CD4+ CD8+ double-positive stage in CD45 gene-deficient (CD45 -/-) mice. Moreover, splicing of variable CD45 exons changes during thymocyte selection. To test the role of CD45 extracellular splice variants in T cell selection and development, we introduced CD45RO (a low-m.w. splice variant lacking exons 4, 5, and 6) and CD45ABC (a high-m.w. isoform containing all exons) transgenes under the control of a thymocyte-specific promoter into a CD45 -/- background, generating CD45RO transgene-positive CD45 -/- (CD45RO) and CD45ABC transgene-positive CD45 -/- (CD45ABC) mice. We demonstrate that both CD45 splice isoforms can rescue development of CD4+ and CD8+ TCR-alphabeta+ thymocytes. Neither CD45 isoform rescued positive selection of H-Y TCR transgene thymocytes, and these cells were blocked at a HSA(high) CD69- CD5(low) stage of development. Peripheral T cells from CD45RO and CD45ABC mice proliferated in response to allogeneic stimulator cells and anti-CD3epsilon cross-linking. However, only CD45RO mice, not CD45ABC mice, generated cytotoxic T cell responses and neutralizing, Th cell-dependent IgG Abs after viral infections. In addition, we show that T cells from CD45RO and CD45ABC mice accumulate in lymph nodes but not in the spleen, liver, or skin, indicating that the CD45 phosphatase may control the homing behavior and trafficking of T cells.

T cell development in mice expressing splice variants of the protein tyrosine phosphatase CD45

The transmembrane protein tyrosine phosphatase CD45 is expressed in multiple isoforms as a result of alternative splicing of variable exons encoding the extracellular domain. CD45 expression is critical for T cell development, and thymocyte maturation is blocked at the immature CD4+ CD8+ double-positive stage in CD45 gene-deficient (CD45 -/-) mice. Moreover, splicing of variable CD45 exons changes during thymocyte selection. To test the role of CD45 extracellular splice variants in T cell selection and development, we introduced CD45RO (a low-m.w. splice variant lacking exons 4, 5, and 6) and CD45ABC (a high-m.w. isoform containing all exons) transgenes under the control of a thymocyte-specific promoter into a CD45 -/- background, generating CD45RO transgene-positive CD45 -/- (CD45RO) and CD45ABC transgene-positive CD45 -/- (CD45ABC) mice. We demonstrate that both CD45 splice isoforms can rescue development of CD4+ and CD8+ TCR-alphabeta+ thymocytes. Neither CD45 isoform rescued positive selection of H-Y TCR transgene thymocytes, and these cells were blocked at a HSA(high) CD69- CD5(low) stage of development. Peripheral T cells from CD45RO and CD45ABC mice proliferated in response to allogeneic stimulator cells and anti-CD3epsilon cross-linking. However, only CD45RO mice, not CD45ABC mice, generated cytotoxic T cell responses and neutralizing, Th cell-dependent IgG Abs after viral infections. In addition, we show that T cells from CD45RO and CD45ABC mice accumulate in lymph nodes but not in the spleen, liver, or skin, indicating that the CD45 phosphatase may control the homing behavior and trafficking of T cells.

Lack of evidence for rotavirus by polymerase chain reaction/enzyme immunoassay of hepatobiliary samples from children with biliary atresia

The purpose of this study was to analyze hepatobiliary samples of patients with biliary atresia for rotavirus groups. A, B, and C, because group A rotavirus had been used to produce an animal model of the disease and group C rotavirus had been found in hepatobiliary samples from one group of patients. Biliary remnants and liver tissue from 10 biliary atresia and 14 control patients with other liver diseases were examined for rotavirus groups A, B, and C using nonisotopic, reverse transcriptase polymerase chain reaction enzyme immunoassay. Biliary atresia patients had a median age of 3 mo and were from a confined geographic area. Rotaviral stocks from groups A and C were used as polymerase chain reaction-positive controls. The limits of detection for rotaviral RNA from these two groups were respectively, 5 plaque-forming units and 50 tissue culture infectious doses (ID50). Tissue culture was 100-fold less sensitive for groups A and C than the polymerase chain reaction. The nested nonisotopic probes hybridized in solution only with their homologous target DNAs as determined by the enzyme immunoassay, or by Southern blot hybridization. Although it was possible to detect mRNA from a beta-actin housekeeping gene in all of the hepatobiliary samples, no evidence of rotaviral RNA was found in either the biliary atresia or the negative control group. In conclusion, rotavirus is not a common viral etiology of biliary atresia.

Association of body mass index with blood pressure in elderly Japanese American men. The Honolulu Heart Program

Few data are available on the association between body mass index (BMI) and blood pressure in elderly individuals, particularly among minority groups. We studied the cross-sectional association of BMI with systolic and diastolic pressures in 1378 Japanese American men 60 to 82 years of age who were participants in the population-based Third Lipoprotein Examination of the Honolulu Heart Program conducted between 1980 and 1982. When the subjects were divided into 5-year age groups, mean BMI decreased linearly with increasing age. Mean systolic pressure rose from 134.8 mm Hg in the first quintile of BMI to 138 in the second and 141.8 in the third quintiles, with levels of 139.2 and 142 in the fourth and fifth quintiles, respectively (test for trend, P = .083). Mean diastolic pressure rose from 78.1 mm Hg in the lowest quintile of BMI to 83.9 in the highest (test for trend, P = .008). We performed multiple regression analysis, controlling for factors known to influence blood pressure values, including age, physical activity index, alcohol intake, current smoking status, and diabetes mellitus. The association between BMI and both systolic and diastolic pressures remained highly statistically significant in these analyses. These results show that obesity and high blood pressure continue to be highly correlated even in old age and suggest that it may be possible to modify rates of hypertension by changes in body weight.

Prevalence of dementia in older Japanese-American men in Hawaii: The Honolulu-Asia Aging Study

OBJECTIVE

To determine prevalence of dementia and its subtypes in Japanese-American men and compare these findings with rates reported for populations in Japan and elsewhere.

DESIGN AND SETTING

The Honolulu Heart Program is a prospective population-based study of cardiovascular disease established in 1965. Prevalence estimates were computed from cases identified at the 1991 to 1993 examination. Cognitive performance was assessed using standardized methods, instruments, and diagnostic criteria.

PARTICIPANTS

Subjects were 3734 Japanese-American men (80% of surviving cohort) aged 71 through 93 years, living in the community or in institutions.

MAIN OUTCOME MEASURES

Age-specific, age-standardized, and cohort prevalence estimates were computed for dementia (all cause) defined by 2 sets of diagnostic criteria and 4 levels of severity. Prevalence levels for Alzheimer disease and vascular dementia were also estimated.

RESULTS

Dementia prevalence by Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised ranged from 2.1% in men aged 71 through 74 years to 33.4% in men aged 85 through 93 years. Age-standardized prevalence was 7.6%. Prevalence estimates for the cohort were 9.3% for dementia (all cause), 5.4% for Alzheimer disease (primary or contributing), and 4.2% for vascular dementia (primary or contributing). More than 1 possible cause was found in 26% of cases. The Alzheimer disease/vascular dementia ratio was 1.5 for cases attributed primarily to Alzheimer disease or vascular dementia.

CONCLUSIONS

Prevalence of Alzheimer disease in older Japanese-American men in Hawaii appears to be higher than in Japan but similar to European-ancestry populations. Prevalence of vascular dementia appears to be slightly lower than in Japan, but higher than in European-ancestry populations. Further cross-national research with emphasis on standardized diagnostic methods is needed.

Reference values for pulmonary function tests of Japanese-American men aged 71 to 90 years

Pulmonary function was assessed by spirometry in 3,076 elderly Japanese-American men of the Honolulu Heart Program (HHP) cohort. The assessment was done with a stringent quality assurance program that adhered to American Thoracic Society (ATS) recommendations for spirometry. Less than 6% of the participants were unable to perform three acceptable spirometry maneuvers. A "healthy" subgroup of 528 men between the ages of 71 and 90 yr was identified by excluding almost all smokers and subjects with lung disease and other factors negatively influencing FEV1. Reference equations and normal ranges for FEV1, FVC, and the FEV1/FVC ratio were derived from the healthy group. Use of prediction equations from the Cardiovascular Health Study (CHS) of elderly European-American men consistently overpredicted FVC by 0.3 to 0.4 L and FEV1 by 0.15 L. Men in the HHP were on average 11 cm shorter than those in the CHS. Use of a prediction equation derived from the HHP cohort when the men in the cohort were on average 22.6 yr younger consistently overpredicted FEV1 by 0.2 to 0.3 L. These results underscore the importance of using prediction equations appropriate to the ethnicity, age, and height characteristics of the subjects being studied.

Hypertension in elderly Japanese Americans and adult native Hawaiians

POPULATION-BASED DATA ON HYPERTENSION IN HAWAII are limited. Two groups for which data from the 1980s exist are Japanese-American men ages 60 to 81 in the Honolulu Heart Program (HHP) and native Hawaiians ages 20 to 59 in the Molokai Heart Study (MHS). In the elderly HHP men, the mean systolic blood pressure (SBP) was higher and the mean diastolic blood pressure (DBP) was lower in the older age groups. In the MHS, both the mean SBP and the mean DBP were higher with increasing age in both sexes. Among Japanese-American men, 53% of those ages 60 to 64 were hypertensive (SBP greater than or equal to 140 mmHg or DBP greater than or equal to 90 mmHg, or taking antihypertensive medications), as were 59% of those ages 65 to 74, and 67% of those ages 75 to 81. Among native Hawaiians, 6% of men and 8% of women ages 20 to 24 were hypertensive, as were 37% of men and 41% of women ages 45 to 54. At ages 55 to 59 the prevalence for men was 31%; and for women, 33%. These data indicate that hypertension is relatively common in both ethnic groups; however, native Hawaiians appear to be at greater risk of cardiovascular disease overall.

Combined effects of HDL cholesterol, triglyceride, and total cholesterol concentrations on 18-year risk of atherosclerotic disease

BACKGROUND

Whether the combination of a low level of HDL cholesterol (HDL-C) and high level of triglyceride (TG) confers increased risk of cardiovascular disease and whether risk varies across levels of total cholesterol (TC) are not well established. Combined effects of HDL-C, TG, and TC on the incidence of atherosclerotic disease were examined prospectively in Japanese-American men from the Honolulu Heart Program.

METHODS AND RESULTS

Among 1,646 men aged 51 to 72 years who were free of coronary heart disease (CHD), stroke, and cancer and were not taking lipid-lowering medication, 318 developed atherosclerotic events (angina, coronary insufficiency, aortic aneurysm, definite CHD, or thromboembolic stroke) and 170 developed definite CHD between 1970 and 1988. Subjects were stratified by TC level (desirable, < 200 mg/dL; borderline high, 200 to 239 mg/dL; high, > or = 240 mg/dL), HDL-C level (< 35 and > or = 35 mg/dL), and TG level (< 200 and > or = 200 mg/dL). With Cox regression with high HDL-C and low TG as reference, age-adjusted relative risks (RR) of atherosclerotic events were significantly elevated in men with low HDL-C and high TG at borderline-high (RR, 2.46; 95% CI, 1.48 to 4.09) and high (RR, 2.21; 95% CI, 1.34 to 3.66) TC levels but not in men with desirable TC levels (RR, 0.89; 95% CI, 0.38 to 2.09). Elevated risks were independent of blood pressure, obesity, fat distribution, diabetes, smoking, and alcohol. Results were not materially altered by exclusion of subjects with angina alone and were similar but somewhat weaker for CHD.

CONCLUSIONS

Risk of atherosclerotic disease appears elevated in subjects with low HDL-C and high TG levels when TC is borderline high or high, independent of other cardiovascular risk factors. These findings support recent cholesterol screening recommendations and suggest that joint effects of HDL-C and TG may be important to consider.

Sudden death, impaired glucose tolerance, and diabetes in Japanese American men

BACKGROUND

Diabetes and glucose intolerance have been shown to increase the risk of cardiovascular mortality in a number of different populations. Most studies have been based on short follow-up periods, and few have had sufficient numbers to allow researchers to look at sudden death as an outcome.

METHODS AND RESULTS

The relation of sudden death, defined as unexpected death occurring within either 1 or 24 hours of first symptoms, to glucose intolerance measured by a nonfasting 1-hour postload measurement made in 1965 or history of diabetes was examined by use of 23 years of follow-up on the 8006 participants enrolled in the Honolulu Heart Program. After adjustment for baseline body mass index, hypertension, cholesterol, triglycerides, smoking, alcohol consumption, and left ventricular hypertrophy or strain, the relative risks for sudden death within 24 hours in individuals with high-normal (151 to 224 mg/dL), asymptomatic high glucose values (> or = 225 mg/dL), and diabetes compared with those with lower glucose values (< 151 mg/dL) were 1.59, 2.22, and 2.76, respectively. All these relative risks were statistically significant (P < or = .05). Trends for sudden death in 1 hour were similar. Among men with sudden death < 1 hour after onset of symptoms, the strength of the association between diabetes and sudden death was stronger among those classified as having died of unknown causes who thus were more likely to have died of an arrhythmia than among those classified as having died of coronary heart disease.

CONCLUSIONS

The relations seen in these analyses indicate that individuals with glucose intolerance or diagnosed diabetes are at increased risk for sudden death.

Lifestyle and biologic factors associated with atherosclerotic disease in middle-aged men. 20-year findings from the Honolulu Heart Program

OBJECTIVES

To examine the association between a variety of baseline lifestyle and biologic factors in a middle-aged cohort of Japanese-American men and the 20-year incidence rates of total atherosclerotic end points and each of the initial clinical manifestations of this disease, including fatal and nonfatal coronary heart disease, angina pectoris, thromboembolic strokes, and aortic aneurysms.

DESIGN

Prospective epidemiologic study.

POPULATION

Japanese-American men (N = 2710) between the ages of 55 and 64 years at the time of the initial clinical examination of the Honolulu Heart Program (1965 through 1968) free from evidence of coronary heart disease, cerebrovascular disease, cancer, or aortic aneurysms.

RESULTS

Among the men studied, 602 atherosclerotic events developed during the 23-year period of follow-up (1965 through 1988). After adjustment for each of the baseline characteristics examined, significant positive associations between quartile cutoffs of body mass index, systolic blood pressure, serum levels of cholesterol, triglycerides, glucose, and uric acid, as well as cigarette smoking, and the occurrence of any atherosclerotic end point were seen, while an inverse association with alcohol consumption was observed. Characteristics associated with the development of other fatal and nonfatal clinical events in this cohort, including coronary heart disease, thromboembolic stroke, and aortic aneurysms are presented with accompanying relative and attributable risks.

CONCLUSIONS

The results of this prospective epidemiologic study provide insights to the long-term predictive utility of the commonly accepted risk factors for coronary heart disease in relation to the different clinical manifestations of atherosclerosis in a middle-aged male cohort followed up for approximately 20 years. These results provide additional support for risk factor modification in middle-aged men and for the encouragement of positive long-term lifestyle changes.

Physical activity and 23-year incidence of coronary heart disease morbidity and mortality among middle-aged men. The Honolulu Heart Program

BACKGROUND

The purpose of the study was to examine the association between physical activity and 23-year incidence of coronary heart disease morbidity and mortality. This cohort study continues to follow 8006 Japanese-American men who were 45 to 68 years of age and living on Oahu, Hawaii, in 1965, for the development of coronary heart disease morbidity and mortality.

METHODS AND RESULTS

The Framingham physical activity index was calculated by summing the product of average hours spent at each activity level and a weighting factor based on oxygen consumption. Study subjects were divided into tertiles of physical activity index at baseline. Relative risks and 95% confidence intervals (CI) for incidence of coronary heart disease morbidity and mortality were obtained using the Cox model. After age adjustment and using the lowest physical activity index tertile as a reference group, the relative risk for coronary heart disease incidence for the highest tertile of physical activity was 0.83 (CI, 0.70 to 0.99). After adjusting for age, hypertension, smoking, alcohol intake, diabetes, cholesterol, and body mass index, the relative risk was 0.95 and CI included 1 (CI, 0.80 to 1.14). For coronary heart disease mortality, the age-adjusted relative risk was 0.74 (CI, 0.56 to 0.97) and 0.85 (CI, 0.65 to 1.13) after risk factor adjustment.

CONCLUSIONS

The results suggest that the impact of physical activity index on coronary heart disease is mediated through its effects on hypertension, diabetes, cholesterol, and body mass index. These findings support the hypothesis that physical activity is inversely associated with coronary heart disease morbidity and mortality and suggest that physical activity interventions in middle-aged men, by improving cardiovascular risk factor levels, may have significant public health implications in the prevention of coronary heart disease.

Glucose intolerance and 22-year stroke incidence. The Honolulu Heart Program

BACKGROUND AND PURPOSE

This study was conducted to determine whether glucose intolerance and diabetes increase the risk of thromboembolic, hemorrhagic, and total stroke independent of other risk factors.

METHODS

Among 7549 Japanese-American men aged 45 to 68 years and free of coronary heart disease and stroke during 1965 to 1968, history of diabetes, diabetic medication, and nonfasting glucose 1 hour after a 50-g load were used to classify subjects into four glucose tolerance categories. Incidence of stroke over 22 years was ascertained using comprehensive hospital-based surveillance. Age- and risk factor-adjusted relative risks of stroke were determined using a Cox proportional hazards model.

RESULTS

A total of 374 thromboembolic, 128 hemorrhagic, and 36 type-unknown strokes occurred. Incidence of thromboembolic but not hemorrhagic stroke increased with worsening glucose tolerance category. Compared with the "low-normal" (glucose < 151 mg/dL) group, subjects in the "high-normal" (151 to 224 mg/dL), "asymptomatic high" (> or = 225 mg/dL), and "known diabetes" groups all had significantly elevated age-adjusted relative risks of thromboembolic stroke. After adjustment for other risk factors, relative risks remained significantly elevated for the asymptomatic high and known diabetes groups (1.43 and 2.45; 95% confidence intervals, 1.00 to 2.04 and 1.73 to 3.47, respectively). Associations were the same in hypertensive and nonhypertensive subjects and similar but slightly stronger in younger (aged 45 to 54 years) than in older (aged 55 to 68 years) men.

CONCLUSIONS

Subjects with diabetes and elevated glucose appear to be at increased risk of thromboembolic but not hemorrhagic stroke. These associations were largely independent of other cardiovascular disease risk factors. Excess risk is apparent in older as well as younger diabetic individuals and in hypertensive and nonhypertensive subjects with diabetes.

A prospective study of the health effects of alcohol consumption in middle-aged and elderly men. The Honolulu Heart Program

BACKGROUND

The study objective was to determine the association between reported alcohol consumption and total mortality, mortality from selected causes, and incident nonfatal chronic disease events in middle-aged (51 to 64 years old) and elderly (65 to 75 years old) men during an approximate 15-year follow-up period.

METHODS AND RESULTS

We conducted a prospective epidemiological study of Japanese-American men who were participating in the Honolulu Heart Program and were free from coronary heart disease, cerebrovascular disease, and cancer at baseline examination and at subsequent reexamination 6 years later. Self-reported alcohol consumption was determined twice: at the baseline examination in 1965 through 1968 and at reexamination approximately 6 years later (1971 through 1974). Four primary alcohol consumption groups who reported similar alcohol intake at the time of these two clinical examinations were considered: abstainers and light (1 to 14 mL of alcohol per day), moderate (15 to 39 mL of alcohol per day), and heavy (> or = 40 mL of alcohol per day) drinkers. Study end points were also determined in very light (1 to 4.9 mL of alcohol per day) drinkers and in men who reported a change in their alcohol intake between examinations. Longitudinal follow-up was carried out through the end of 1988 with determination of selected fatal and nonfatal events according to alcohol intake. After controlling for several potentially confounding factors, total mortality exhibited a J-shaped pattern in relation to alcohol consumption in middle-aged and elderly men. There was a trend for lower rates of occurrence of combined fatal and nonfatal coronary heart disease events with increasing alcohol consumption in both middle-aged and elderly men. Increasing alcohol consumption was related to an increased risk of fatal and nonfatal strokes in middle-aged men, whereas elderly light and moderate drinkers were at increased risk for fatal and nonfatal strokes. Heavy drinkers were at increased risk for fatal and nonfatal malignant neoplasms in the two age groups examined.

CONCLUSIONS

The results of this long-term prospective study provide a balanced perspective of the health effects of alcohol consumption in middle-aged and elderly men. High levels of alcohol consumption were shown to be related to an increasing risk of diseases of considerable public health importance. These findings suggest that caution be taken in formulating population-wide recommendations for increases in the population levels of alcohol consumed given the associated significant social and biological problems of high consumption levels.

The Cognitive Abilities Screening Instrument (CASI): a practical test for cross-cultural epidemiological studies of dementia

The Cognitive Abilities Screening Instrument (CASI) has a score range of 0 to 100 and provides quantitative assessment on attention, concentration, orientation, short-term memory, long-term memory, language abilities, visual construction, list-generating fluency, abstraction, and judgment. Scores of the Mini-Mental State Examination, the Modified Mini-Mental State Test, and the Hasegawa Dementia Screening Scale can also be estimated from subsets of the CASI items. Pilot testing conducted in Japan and in the United States has demonstrated its cross-cultural applicability and its usefulness in screening for dementia, in monitoring disease progression, and in providing profiles of cognitive impairment. Typical administration time is 15 to 20 minutes. Record form, manual, videotape of test administration, and quizzes to qualify potential users on the administration and scoring of the CASI are available upon request.

Lability of red blood cell membranes to lipid peroxidation: application to humans fed polyunsaturated lipids

Red blood cell membranes (RBCM) were used to estimate human red blood cell lability to lipid peroxidation in vitro. RBCM were prepared from blood collected from humans fed diets with either 3 or 15% polyunsaturated fatty acids for 80 days. RBCM were isolated by centrifugation, and oxidative stress was induced by in vitro incubation with 0.1 or 0.5 mM tert-butyl hydroperoxide (t-BOOH) in the presence of 0.5 mg added hemoglobin. Lipid Peroxidation was evaluated by measurement of thiobarbituric acid-reactive substances (TBARS). Lipid peroxidation correlated with the protein content of RBCM in both noninduced and t-BOOH-induced lipid peroxidation systems. TBARS production was dependent on the amount of t-BOOH added to the RBCM. The production of TBARS by RBCM incubated with 0.5 mM t-BOOH was correlated with arachidonic acid content in the red blood cells (RBC) from which RBCM were prepared. The methodology developed was useful for comparative estimations of the lability of RBCM to lipid peroxidation.

Vitamin C deficiency in patients with sickle cell anemia

Because peroxidative damage to red cell membranes may contribute to the pathophysiology of sickle cell disease, deficiency of fat- and water-soluble antioxidants could be a determinant in the pathogenesis of this disease. We have previously reported a deficiency of vitamin E in sickle cell disease. The present study was undertaken to see if a deficiency in vitamin C might also be detected. Leukocyte vitamin C, which reflects total body vitamin C reserve, was measured by a modified 2,4-dinitrophenylhydrazine method. Sickle cell patients (N = 18) had lower leukocyte vitamin C levels (18.3 +/- 9.4 micrograms/10(8) cells) than normal controls (N = 12; 30.3 +/- 7.5 micrograms/10(8) cells; p less than 0.01). Furthermore, 50% of the patients had vitamin C levels below 15 micrograms/10(8) cells, a value consistent with vitamin C deficiency. A statistically significant correlation (r = -0.62 with 0.01 less than p less than or equal to 0.025) was found between leukocyte vitamin C levels and serum ferritin concentration. Because dietary vitamin C intake appeared to be adequate, increased vitamin C utilization may account for this deficiency. However, the mechanisms for this deficiency as well as its pathophysiologic consequences remain to be established.

Lipid peroxidation in human red cells

In this review we have discussed the chemistry and biochemistry of lipid peroxidation as well as lipid repair mechanisms in human RBCs. We have presented findings relating to the effect of lipid peroxidation on the RBC membrane and on several properties that are determinants of RBC survival in vivo. Since we have not discussed how oxidative damage to membrane proteins or hemoglobin may affect RBC survival, the role of lipid oxidation must be considered in a broader perspective. Considerable evidence has recently been reported to indicate that oxidative hemoglobin denaturation plays an extremely important role in RBC survival. Since all cellular components are susceptible to peroxidative damage, it is likely that multiple reactions will be important with regard to RBC oxidant injury, just as they have been implicated in many degenerative processes, and that certain "compartments" of the membrane may be more susceptible than others due to congenital or acquired defects in membrane structure.

Lipid alterations and cellular properties of sickle red cells

Taken together, our studies and those in other laboratories demonstrate a number of membrane lipid changes in sickle erythrocytes. These include (1) changes in membrane phospholipid dynamics, (2) perturbation of the translocase protein that translocates aminophospholipids from the exterior leaflet to the interior leaflet, (3) perturbation of the interaction between membrane phospholipids and skeletal proteins, and (4) abnormal phospholipid molecular species compositions. The mechanism underlying these alterations may involve several independent effects. Included in these will be the oxidative damage that occurs to these membranes and the dissociation of lipids and proteins that accompanies the sickling process.

Oxidative hemoglobin denaturation and RBC destruction: the effect of heme on red cell membranes

In this article, we have reviewed evidence to indicate that hemoglobin denaturation can cause sufficient membrane damage to contribute to red cell destruction. We have attempted to explain how hemoglobin denaturation may affect red cell membrane properties at the molecular level. Current information is consistent with the possibility that hemin, in addition to Heinz bodies, is an important factor contributing to red cell membrane damage following hemoglobin denaturation. The initial step in hemin-induced membrane damage appears to involve the oxidation of membrane protein sulfhydryl groups as well as lipids. Structural and functional membrane properties are likely to be altered. Further studies on the role of hemin in the process of red cell aging and in the pathophysiology of red cell disorders characterized by hemoglobin oxidation should yield new information regarding the role of hemin in these conditions.

The use of cis-parinaric acid to determine lipid peroxidation in human erythrocyte membranes. Comparison of normal and sickle erythrocyte membranes

The recently developed parinaric acid assay is shown to offer possibilities for studying peroxidation processes in biological membrane systems. Taking the human erythrocyte membrane as a model, several initiating systems were investigated, as well as the effect of residual hemoglobin in ghost membrane preparations. The effectivity of a radical generating system appeared to be strongly dependent upon whether radicals are generated at the membrane level or in the water phase. Thus, cumene hydroperoxide at concentrations of 1.0-1.5 mM was found to be a very efficient initiator of peroxidation in combination with submicromolar levels of hemin-Fe3+ as membrane-bound cofactor. In combination with cumene hydroperoxide, membrane-bound hemoglobin appeared to be about 6-times more effective in promoting peroxidation than hemoglobin in the water phase. Results comparing the behaviour of normal and sickle erythrocyte ghost suspensions in the peroxidation assay suggest that the increased oxidative stress on sickle erythrocyte membranes could be due to enhanced membrane binding of sickle hemoglobin, but also partly to a characteristically higher capability of sickle hemoglobin to promote peroxidation. The order of peroxidation-promoting capabilities that could be derived from the experiments was hemin greater than sickle hemoglobin greater than normal hemoglobin.