Influence of health insurance status on breast cancer diagnosis and treatment delay: A safety net hospital's experience

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Background: Given barriers to access, uninsured women with breast cancer might experience delays in diagnosis and treatment when compared to insured women. The influence of insurance status on breast cancer outcome was addressed at a single institution whose mission statement requires that all pts be treated the same, regardless of their ability to pay Methods: Records of all pts with breast cancer seen from 1/00- 12/04 at a safety net hospital were reviewed. Insurance status was defined at the time of the first abnormal mammogram. Cases were divided into Group A (private insurance), B (medicaid or medicare) or C (uninsured). Time to diagnosis (TDx) was defined as the interval from abnormal mammogram to pathologic diagnosis of breast cancer. Time to treatment (TRx) was defined as time from pathologic diagnosis to definitive surgical therapy. Results: 560 cases were reviewed. Group A: 48%, B: 33%, C: 19%. Median age= 57 (GrpA=53, B= 67, C= 55). Race Caucasian 59%; AA 34%; other 7%. Stage (0, I, II, III and IV, in %, respectively): Grp A= 14.6, 42.9, 31.5, 7.1 and 3.9; Grp B= 13.1, 46, 22.7, 12.5 and 5.7; Grp C = 13.9, 33.7, 32.7, 11.9 and 7.9. No significant diff between groups, although there was a trend towards later (III/IV) pts in grps B and C than A (18.2% and 19.8% vs 10.9%, respectively). Mean TDx: Grp A= 50.6 days, B= 68.1d and C=52.8d; p= 0.006 when Group B was compared to the other two groups but there was no difference between uninsured and private groups. Mean TRx: 43.8d, 48.6d and 47.8 days, respectively, for groups A, B and C, without any statistical difference between any of the groups. Conclusions: A 5-year review of breast cancer cases at a large safety net hospital did not reveal any difference in the time to diagnosis or initiation of treatment for insured vs. uninsured pts. Uninsured and medicaid/medicare pts tended to present with later stage disease, perhaps due to access problems. A statistically significant delay in diagnosis was noted in the medicaid/medicare group but it is unlikely that this difference (18 days) was clinically important. Because uninsured pts are provided care at greatly discounted rates at our institution, these results may differ from those at other institutions. Further studies addressing this issue are warranted.

No significant financial relationships to disclose.

Cardiovascular gene therapy: current status and therapeutic potential

Gene therapy is emerging as a potential treatment option in patients suffering from a wide spectrum of cardiovascular diseases including coronary artery disease, peripheral vascular disease, vein graft failure and in-stent restenosis. Thus far preclinical studies have shown promise for a wide variety of genes, in particular the delivery of genes encoding growth factors such as vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) to treat ischaemic vascular disease both peripherally and in coronary artery disease. VEGF as well as other genes such as TIMPs have been used to target the development of neointimal hyperplasia to successfully prevent vein graft failure and in-stent restenosis in animal models. Subsequent phase I trials to examine safety of these therapies have been successful with low levels of serious adverse effects, and albeit in the absence of a placebo group some suggestion of efficacy. Phase 2 studies, which have incorporated a placebo group, have not confirmed this early promise of efficacy. In the next generation of clinical gene therapy trials for cardiovascular disease, many parameters will need to be adjusted in the search for an effective therapy, including the identification of a suitable vector, appropriate gene or genes and an effective vector delivery system for a specific disease target. Here we review the current status of cardiovascular gene therapy and the potential for this approach to become a viable treatment option.

Evidence suggests rigid aortic grafts increase systolic blood pressure: results of a preliminary study

Abdominal aortic aneurysm (AAA) is a serious complication of the aorta and is treated using vascular bypass grafts. Two main classes of graft are available to treat AAA; grafts implanted by open surgery and stent-grafts implanted using minimally invasive endovascular techniques. Both classes of graft consist of an aortic section which bifurcates into two iliac sections. It has been hypothesized that implantation of aortic grafts and stent-grafts serve to significantly increase abdominal aortic pressures. In this study, an open-loop computer-controlled pumping system was built to produce physiologically realistic pressure and flow-rates. Models of a compliant abdominal aortic aneurysm, a compliant walled graft and a tapered graft were manufactured using an injection moulding technique and fused deposition modelling was used to create a rigid walled graft. A specific transient flow-rate waveform was then applied at the inlet of each model and the resulting pressure waveforms 30 mm upstream from the bifurcation was recorded. Peak pressure measurements were recorded over the course of the pulse for each model. The compliant aneurysm model was found to have a systolic pressure of 107 mmHg while the complaint graft model was 153 mmHg. The rigid graft model had a peak systolic pressure of 199 mmHg. In the tapered graft, the peak pressure dropped to 142 mmHg. The data suggests that implanting a graft model in place of an aneurysm model in an in vitro flow circuit can increase the pressures recorded upstream from the iliac bifurcation and that tapered grafts may alleviate this problem.

Factors associated with pelvic retraction during gait in cerebral palsy

Clinical and dynamic (gait-related) measures thought to be associated with pelvic retraction were investigated in patients with cerebral palsy. Gait laboratory data of 233 patients with cerebral palsy were studied retrospectively. Two groups were selected; those who demonstrated pelvic retraction during gait <-6.85 degrees (mean - 2 standard deviations from normal (n=88) and those with >-4.83 degrees (mean - 1 standard deviation from normal) (n=101). About 37.8% of the total population reviewed showed pelvic retraction of <-6.85 degrees . There was a higher prevalence of retraction among hemiplegics (46.3%) compared to diplegics (30.4%). Differences were also found between hemiplegic and diplegic subjects in terms of factors associated with pelvic retraction. Clinical and dynamic tightness of the gastro-soleus were the most significant features associated with pelvic retraction among hemiplegic subjects. Clinical and dynamic flexion and internal rotation of the hip were the most significant features associated with retraction in the diplegic population. This study suggests that pelvic retraction is multifactorial in origin and secondary to both static clinical measures as well as dynamic features during gait.

Effect of gene delivery of NOS isoforms on intimal hyperplasia and endothelial regeneration after balloon injury

Endothelial cell loss is a critical event in the pathological repair of the injured blood vessel. Impaired endothelial function results in reduced production of key vascular mediators such as nitric oxide (NO) within the vessel wall leading to enhanced smooth muscle cell proliferation and migration and ultimately intimal hyperplasia. The aim of the present study was to directly compare the effects of adenoviral-mediated gene delivery of two nitric oxide synthase (NOS) isoforms, eNOS and iNOS on endothelial regeneration and intimal hyperplasia following endothelial injury in the rabbit carotid artery. The right carotid arteries of male New Zealand white rabbits were denuded by passing a 3French Fogarty balloon catheter along the artery three times. In all, 1 x 10(9) PFU of adenoviral(Ad)eNOS, AdiNOS or Adbeta-galactosidase (Adbeta-Gal) was then delivered intraluminally and allowed to dwell for 20 min. Transgene expression was sought after 3 days by immunohistochemistry and at 7 days by quantitative reverse transcriptase PCR. The effect on intimal hyperplasia was sought using histological staining after 14 days. Evans blue staining was used to determine the effect on endothelial regeneration. eNOS and iNOS expression was detected in transduced arteries. Neointima/media ratios were significantly reduced in eNOS (0.07+/-0.044) and iNOS (0.087+/-0.086) transduced arteries compared with Adbeta-Gal (0.332+/-0.14) transduced arteries (n=7). In addition, AdeNOS treatment (4.21+/-3.12% de-endothelialized area) enhanced endothelial regeneration compared to Adbeta-Gal treatment (10.05+/-4.98), while treatment with AdiNOS (25.17+/-11.92) inhibited endothelial regeneration in the injured rabbit carotid artery (n=7-8). These results highlight the potential of NOS gene therapy, in particular, eNOS gene therapy as a potential therapeutic strategy for the prevention of restenosis after vascular injury.

Adolescent and young adult cancer: a revolution in evolution?

The optimal management of adolescent and young adult cancer has been the subject of vigorous debate in paediatric and adult cancer community for many years. This debate is rapidly coming to the boil. There is international recognition that not only is cancer in young people on the rise but also that improvements in outcomes of cancer in young people lag well behind the advances that have been achieved for both children and older adults in the past 30 years. The underlying problems appear to relate to a complex set of interactions between the health-care system and the prevalence of cancer in this age group and the unique psychosocial and educational needs of this population. This article explores why we should be concerned about Australian health outcomes in this group and considers how best we might respond to these concerns.

Vitamin D insufficiency in older female community-dwelling acute hospital admissions and the response to supplementation

OBJECTIVES

A significant proportion of the older population may exhibit vitamin D insufficiency. We sought to establish the proportion of 25-hydroxyvitamin D (25OHD) insufficient individuals in an older female cohort presenting for acute medical admission and how they responded to supplementation.

DESIGN

A prospective cohort study.

SETTING

Hospital admissions followed up as a population-based study.

SUBJECTS

A total of 114 consecutive female acute medical admissions aged over 65 years from November 2003 to January 2004 were enrolled. All admissions with hypercalcaemia, metabolic bone disease (other than osteoporosis/osteomalacia) and creatinine > 150 micromol/l were excluded.

INTERVENTIONS

iPTH, calcium and 25OHD levels were measured in each patient. Of the total, 22 were already receiving calcium and vitamin D supplementation at enrolment. The remaining 92 were commenced on 800 IU of vitamin D and 1 g calcium, and levels were reassessed after supplementation for 3 months.

RESULTS

25-Hydroxyvitamin D insufficiency, as defined by a 25OHD concentration of < 50 nmol/l, was present in 86 (75.4%) patients at initial assessment (mean 35.8 nmol/l, s.d. 23.3). Secondary hyperparathyroidism was present in only 36.7% of those with 25OHD deficiency at baseline. Of the total, 51 (44.7%) patients presented for follow-up. 25-Hydroxyvitamin D concentration increased in this group from 42.1 nmol/l (s.d. 26.6) to 59.5 nmol/l (s.d. 27.4) after supplementation, P < 0.001, but 18(35.3%) still remained deficient. There was no significant change in iPTH or calcium following supplementation. Assessment of compliance revealed 6 (11.7%) admitted to partial or non-compliance.

CONCLUSIONS

Insufficiency of 25OHD was very common in this cohort. Despite calcium and vitamin D supplementation, 25OHD concentrations failed to reach normality in a significant proportion. Maintaining vitamin D and calcium intake at the level of current recommended doses may not be sufficient to ensure adequate 25OHD stores.

Ophthalmoplegia in tiger snake envenomation

Herein, we present the case of a 67-year-old grazier who was bitten by a tiger snake and developed coagulopathy and respiratory distress. The patient required intubation and ventilation in intensive care. There was delayed detection of snake envenomation and administration of antivenom. On extubation several days later, gross external ocular paresis was noted. Clinical testing indicated that the ocular pathology was secondary to neurotoxin-mediated presynaptic blockade. The paresis was partially resolved by the time of discharge one week later. The present case report discusses the possible mechanisms for the delayed development of ophthalmoplegia.

Purification of adenovirus and adeno-associated virus: comparison of novel membrane-based technology to conventional techniques

Adenovirus (Ad) and Adeno-associated virus (AAV) are efficient gene delivery systems; manipulation of the wild-type genome allows their use as vectors for the overexpression of desirable transgenes. Generation and purification of such viral vectors can be labour intensive, costly and require specialized equipment, but a new generation of membrane-mediated ion exchange kits for purification of recombinant virus may facilitate this process. Here, we examine the yields, transgene expression and purity of preparations of Ad and AAV purified using commercially available kits in comparison to other established techniques for purification of recombinant viral vectors. We demonstrate comparable results for Ad and AAV respectively in all parameters investigated, with a substantial reduction in purification time for the kit-based technology. Such approaches are attractive methods for small-scale purification of recombinant Ad and AAV viral vectors.

Gene Transfer into Rat Mesenchymal Stem Cells: A Comparative Study of Viral and Nonviral Vectors

Mesenchymal stem cells (MSCs) have been proposed for use in combinatorial gene and cell therapy protocols for the treatment of disease and promotion of repair. The efficacy of such a therapeutic approach depends on determination of which vectors give maximal transgene expression with minimal cell death. The study was carried out on bone-marrow derived rat MSCs, and a range of vectors was tested on the same stem cell preparation. Adenovirus, adeno-associated virus (AAV; serotypes 1, 2, 4, 5, and 6), lentivirus, and nonviral vectors were compared. Lentivirus proved to be most effective with transduction efficiencies of up to 95%, concurrent with low levels of cell toxicity. Adenovirus also proved effective, but a significant increase in cell death was seen with increasing viral titer. Rat MSCs remained refractory to transduction by all AAV serotypes, in contrast to rabbit MSCs tested at the same time. Lipofection of plasmid DNA gave moderate transfection levels but was also accompanied by cell death. Electroporative gene transfer proved ineffective at the parameters tested and resulted in high cell death. High and moderate levels of cell transduction using lentivirus vectors did not affect the ability of the cells to differentiate down the adipogenic pathway.

Altering end-to-side anastomosis junction hemodynamics: the effects of flow-splitting

The long-term patency rate of peripheral artery bypass grafts remains low. Several theories exist which attempt to explain the disease forming mechanisms at the disease prone distal junction of the bypass graft. Common to these theories is that abnormal hemodynamics and wall mechanics contribute to the development of disease at the junction. This study describes a means by which the hemodynamics in the end-to-side anastomosis can be altered by inserting a flow-split into the junction, the function of which is to divert the flow away from the artery bed and toward the sidewalls. Velocity vectors through the junction are significantly altered, and artery centreline WSS magnitudes decrease by up to 36% during the deceleration phase of the flow pulse. Corresponding wall shear stress gradients are found to decrease by 49%. However, locations along the artery sidewall have been identified with increased WSS. It is possible to significantly alter junction hemodynamics using a flow-splitter.

Injection-moulded models of major and minor arteries: the variability of model wall thickness owing to casting technique

Cardiovascular disease of major and minor arteries is a common cause of death in Western society. The wall mechanics and haemodynamics within the arteries are considered to be important factors in the disease formation process. This paper is concerned with the development of an efficient computer-integrated technique to manufacture idealized and realistic models of diseased major and minor arteries from radiological images and to address the issue of model wall thickness variability. Variations in wall thickness from the original computer models to the final castings are quantified using a CCD camera. The results found that wall thickness variation from the major and minor idealized artery models to design specification were insignificant, up to a maximum of 16 per cent. In realistic models, however, differences were up to 23 per cent in the major arterial models and 58 per cent in the minor arterial models, but the wall thickness variability remained within the limits of previously reported wall thickness results. It is concluded that the described injection moulding procedure yields idealized and realistic castings suitable for use in experimental investigations, with idealized models giving better agreement with design. Wall thickness is variable and should be assessed after the models are manufactured.

Current status of catheter- and stent-based gene therapy

Significant progress has been made in the field of cardiovascular gene therapy over the past decade. Animal models of human disease have helped in identifying potential therapeutic genes and have also assisted in the evaluation of an ideal vector. A number of percutaneous catheter systems have been used in animal models with limited success. Stents represent an attractive alternative for localized gene delivery, as they provide a platform for prolonged gene elution and efficient transduction of opposed arterial walls. This gene delivery strategy has the potential to decrease the systemic spread of the viral vectors and hence a reduced host immune response. Both synthetic and naturally occurring stent coatings have shown potential to allow prolonged gene elution with no significant adverse reaction. However, further animal studies are required to evaluate the compatibility of stent coatings, vector solutions, and the arterial wall as well as assessment of the feasibility of this approach to achieve the full potential of gene therapy.

Characterisation of three novel canine osteosarcoma cell lines producing high levels of matrix metalloproteinases

Three canine osteosarcoma cell lines were established from spontaneous pelvic and radial osteosarcomas. The cell populations cultured exhibited characteristics of malignancy and consisted of adherent, pleomorphic, mostly large spindle-shaped or polyhedral cells, characterised by the presence of numerous cytoplasmic granules and vacuoles. The main ultrastructural features included the presence of abundant rough endoplasmic reticulum and numerous cytoplasmic vesicles, deposit vacuoles and small cytoplasmic protrusions. Zymography showed that the cell lines produce high levels of MMP-2 and MMP-9, enzymes directly involved in crucial aspects of the metastatic process. Consistent with their osteoblastic lineage and malignant phenotype, all cell lines were immunoreactive to vimentin, osteopontin, PCNA, p53, MMP-2 and MMP-9, while they were negative for cytokeratin, desmin, SMA, Factor VIII, NSE, GFAP, Rb and p21 protein. No retroviral particles or RNA were detected ultrastructurally or with RT-PCR, although the possibility of viral involvement in osteosarcoma cannot be excluded. The new cell lines provide excellent in vitro models that may allow further studies on the pathobiology of canine osteosarcoma to be undertaken.

Parenteral feeding in a patient with hypertriglyceridemia and increased liver enzyme levels

OBJECTIVE

To discuss nutritional support in a patient with hypertriglyceridemia and liver dysfunction.

METHODS

We describe the hospital course of a critically ill patient with hepatic dysfunction and hypertriglyceridemia who required nutritional support, and we provide an overview of lipid metabolism.

RESULTS

A 27-year-old man with hepatic dysfunction and hypertriglyceridemia, who had undergone kidney transplantation 4 months previously, was admitted to the intensive-care unit with upper gastrointestinal bleeding. He was unable to tolerate enteral feeding, and central parenteral nutrition was initiated. Calories from dextrose and fat were limited because of the presence of increased liver enzyme levels and hypertriglyceridemia. A modified regimen of parenteral nutrition was developed for the patient. The short-term reduction of total calories to 75% of the predicted need is safe.

CONCLUSION

Nutritional support in patients with liver dysfunction and hypertriglyceridemia is complicated and may require temporary underfeeding because of the need to limit fat and dextrose intake.

A randomised trial of periprostatic local anaesthetic for transrectal biopsy

Increasingly transrectal ultrasound and biopsy is performed for the detection of prostate cancer. We have conducted a randomised trial to evaluate whether the addition of periprostatic local anaesthetic injection reduces the discomfort of the procedure. A total of 64 patients who attended a specialised prostate clinic and were being evaluated for an elevated prostate-specific antigen agreed to participate in the trial and were randomly allocated to two groups. The intervention group received 10 ml of 1% lignocaine in the periprostatic tissue prior to biopsy and the control group underwent a standard biopsy. All patients had a sextant biopsy under ultrasound guidance. After the procedure, they were asked to determine the severity of the pain on a scale of 0-10 and the whether the quality of the pain was mild, moderate or severe. The responses were distributed normally. The groups were compared using Student's t-test. Pain severity showed no significant difference between the two groups (P=0.14). There was a trend towards a statistical difference (P=0.07) on the qualitative pain scale. In conclusion, no significant difference in overall discomfort in men having sextant biopsies was detected between the two groups, suggesting that the administration of local anaesthetic may not be as valuable as early reports have suggested.

Movements at the low back during normal walking

We present a technique for measuring the kinematics of the functional low back during normal gait. We have used a similar technique previously to measure low back movement simultaneously with hip, knee, and ankle movement during the toe-touching manoeuvre. We noted that movements at the low back were biphasic. The greatest low back movements were found to occur in the transverse plane (mean = 23 degrees), whereas a mean of 17 degrees movement occurred in the coronal plane and only 5 degrees movement in the sagittal plane. These findings confirm, using a non-invasive technique, that there are significant ranges of movement at the low back during walking and lend some support to the theory that rotational movement at the low back is a major component of human locomotion.

Kinematics of the toe touching test: An investigation using motion analysis

We describe a technique for measuring dynamic motion at the low back along with the major lower limb joints during the toe touching maneuver. This type of motion analysis was carried out on eight normal volunteers. Flexion during the toe touching maneuver involves not only low back and hip movement but also ankle plantar flexion and a varying degree of knee movement. The low back and ankle movements were highly correlated within each subject to an extent that suggests a functional connection between the lower limb and low back movements. The significance of our work is two-fold. First, we emphasize that the toe touching test represents a combined movement of the low back, the hips, the knees, and the ankles and it is reasonable to suggest that abnormalities of these joints may affect the clinical relevance of the test as an indicator of back movement. Second, we point out that the guidelines of the American Medical Association in using the test to determine hip movement are incorrect as they do not take into account the effect of knee and ankle movements on the estimation of hip movement.

On the Existence of an Optimum End-to-side Junctional Geometry in Peripheral Bypass Surgery—A Computer Generated Study

BACKGROUND

To investigate hemodynamic flow changes associated with vein cuffs and patches that may be responsible for improved patency of prosthetic infrainguinal grafts.

METHODS

The role of the graft-artery junction angle was examined by computational fluid dynamics to assess the influence of anastomotic geometry on wall shear stress (WSS) distributions. Three geometrically different junction configurations were studied and the WSS and WSS gradient (WSSG) values were compared.

RESULTS

The inclusion of a patch or a cuff moves the bed stagnation point (BSP) distally, increasing the area on the bed of the junction which experiences a BSP and reducing the strength of the recirculation region opposite the heel of the junction by 54.8 and 50.8%, respectively. The patched geometry promotes earlier recovery of the flow in the distal outflow segment (DOS) than for the unpatched model. Also, the helical flow patterns in the DOS associated with the cuffed geometry are stronger. The net effect of these changes are that peak WSSG values for the patched and cuffed geometries are three times lower than those for the uncuffed geometry.

CONCLUSION

This study provides some additional insights into the hemodynamics of graft-artery junction geometry which may influence future clinical practice.

Classic papers in Urology

OBJECTIVE

Most clinicians are aware of the importance of using "evidence based medicine" to support their clinical practice, but where does the evidence come from? The aim of this study was to examine the concordance between papers deemed "important" by urologists compared with those selected by the more objective criteria of the citation index.

METHOD

To achieve this, two approaches were used; firstly "experts" in various fields of urology were asked to select what they felt were classic papers and secondly urology journals were searched to find the 100 most cited papers for 1982-1997 and 1935-1997. The results of both of these "league tables" were then combined.

RESULTS

The most cited papers varied depending on the time period studied. When the experts' selections were combined with those obtained via citation index it was found that the experts had chosen papers with a high citation index from non-urological as well as urological journals.

CONCLUSION

It is possible to collate the classic papers within urology and the most effective means of doing so is to combine objective selection with expert choice. This is an exercise that can be repeated within any specialty.

On using experimentally estimated wall shear stresses to validate numerically predicted results

The objective of this investigation was to assess the use of experimentally estimated wall shear stresses to validate numerically predicted results. The most commonly cited haemodynamic factor implicated in the disease initiation and proliferation processes at graft/artery junctions is wall shear stress (WSS). WSS can be determined from the product of the viscosity of the fluid and the wall shear rate. Numerically, the wall shear rate is predicted using velocity values stored in the computational cell near the wall and assuming zero velocity at the wall. Experimentally, the wall shear rate is estimated by applying a curve-fit to near-wall velocity measurements and evaluating the shear rate at a specific distance from the wall. When estimating the wall shear rate from the laser Doppler anemometry (LDA) point velocity measurements, large differences between the experimentally estimated and numerically predicted WSSs were introduced. It was found that the estimated WSS distributions from the experimental results are highly dependent on the curve-fitting method used to calculate the wall shear rate. However, the velocity profiles for both the experimental and numerical investigations show extremely good comparison. It is concluded that numerical models should be validated using unprocessed LDA point velocity measurement and not estimated WSS values.

Erectile dysfunction: cardiovascular risk and the role of the cardiologist

Erectile dysfunction (ED) shares the same risk factors as coronary artery disease, so the level of occult cardiovascular risk in men with ED was assessed. A total of 174 men presenting with ED underwent cardiac risk stratification according to the Princeton Consensus Guidelines. Thirty per cent were stratified as intermediate/high cardiovascular risk and had ED treatment deferred until further cardiological assessment; 37% had abnormal lipid profiles; 24% had elevated HbA1C/glucose levels; 17% had uncontrolled hypertension; and 6% were suspected of having significant angina. ED is associated with a high incidence of occult cardiovascular disease. We suggest that cardiologists can significantly contribute to the management of ED.

A direct mechanical method for accurate and efficient adenoviral vector delivery to tissues

We describe a mechanical method for delivery of adenoviral vector to the adventitial surface of arteries and to other tissues. Our goal was to characterize, principally in intact carotid artery, the morphological, biochemical, and functional effects of mechanical delivery of a recombinant beta-galactosidase-expressing adenoviral vector following its direct application using a small paintbrush. Our ex vivo and in vivo data demonstrate efficient, accurate, and rapid transduction of arteries without compromise of their morphological, biochemical, and functional integrity. We also demonstrate the general applicability of this technique in vivo via transduction of skeletal muscle, fibrotendinous tissue, peritoneum, serosal surface of bowel, and wounded skin. We conclude that direct mechanical delivery of an adenoviral vector to tissues using a suitable paintbrush represents an intuitive, accurate, and effective means of augmenting gene transfer efficiency, and may be a useful adjunct to other delivery methods.

In vitro toxicity of 7H-dibenzo[c,g]carbazole in human liver cell lines

7H-Dibenzo[c,g]carbazole (DBC) is a model N-heterocyclic aromatic compound (NHA) which is both a hepatotoxin and hepatocarcinogen in rodents. The focus of this investigation was to determine whether human liver cell lines display differential sensitivities to DBC-induced toxicity. Treatment of cell lines with increasing DBC concentrations produced apoptosis only in HepG2 cells. Although DBC inhibited the clonogenic growth of all cell lines at high concentrations, only the survival of HepG2 cells was reduced at lower concentrations. DBC inhibited DNA synthesis in two (HepG2, HLF) of the three cell lines at lower concentrations and was effective only at a high concentration in Mahlavu cells. Differences in DBC uptake were not observed in any of the cell lines, suggesting that bioavailability was not a limiting factor. DBC-DNA adducts were not detected in HLF or Mahlavu cells at either low or high concentrations of DBC. Consistent with the DNA adduct data, RP-HPLC analysis indicated that DBC was metabolized to a lesser degree in the HLF and Mahlavu cells. These results suggest that human liver cell lines differ markedly in the ability to metabolize DBC to toxic species and that DBC-induced apoptosis is only observed in cells that produce detectable metabolites and DBC-DNA adducts.

Low-density lipoprotein apheresis for the treatment of refractory hyperlipidemia

The advent of treatment with 3-hydroxy-3-methylglutaryl coenzyme A inhibitors has meant that, with a combination of diet and drug therapy, adequate control of serum cholesterol concentrations can be achieved in most patients with hypercholesterolemia. However, some patients, primarily those with familial hypercholesterolemia (FH), may require additional therapy to lower their cholesterol levels. In recent years, low-density lipoprotein (LDL) apheresis has emerged as an effective method of treatment in these patients. The criteria for commencement of LDL apheresis are LDL cholesterol levels of 500 mg/dL or higher for homozygous FH patients, 300 mg/dL or higher for heterozygous FH patients in whom medical therapy has failed, and 200 mg/dL or higher for heterozygous FH patients with documented coronary disease and in whom medical therapy has failed. In addition to cholesterol lowering in patients with FH, other indications for LDL apheresis are emerging. These include its use in the treatment of graft vascular disease in patients receiving cardiac transplants as well as in the treatment of certain glomerulonephritides. This review examines the role of LDL apheresis in the management of lipid disorders and the evidence available to support its use in clinical practice.

Gene transfer of manganese superoxide dismutase reverses vascular dysfunction in the absence but not in the presence of atherosclerotic plaque

Impaired endothelium-dependent vasorelaxation (EDVR) is observed in hypercholesterolemia both in the presence and absence of morphological abnormalities and may be due to superoxide anions. Our aim was to assess the effect of gene transfer of manganese superoxide dismutase (MnSOD) to blood vessels from hypercholesterolemic animals with and without atherosclerotic plaque and to compare the effects of endothelial nitric oxide synthase (eNOS) and MnSOD over-expression on vascular dysfunction in the setting of atherosclerosis. Rabbits received a high-cholesterol diet for 10 weeks, resulting in abnormal EDVR in the absence of plaque in the carotids and the presence of plaque in the aorta. In Group 1, adenoviral vectors encoding MnSOD (AdMnSOD) or beta-galactosidase (Ad(beta)gal) were delivered to the carotid arteries in vivo. Four days later, transgene expression and vascular reactivity were assessed. In Group 2, segments of the aorta were transduced ex vivo with AdMnSOD, AdeNOS or both. Transgene expression and vascular reactivity were assessed 24 hr later. In Group 1, MnSOD expression was detected in AdMnSOD-ransduced vessels and impaired EDVR was reversed in the absence of atherosclerotic plaque. In Group 2 (with atherosclerotic plaque present), MnSOD and eNOS expression were detected by western analysis, and eNOS, but not MnSOD over-expression, improved EDVR whereas simultaneous over-expression of eNOS and MnSOD was no better than eNOS alone. Adenovirus-mediated gene transfer of MnSOD to nonatherosclerotic carotid arteries, but not atherosclerotic aorta, normalizes EDVR. eNOS gene transfer improves EDVR, even in the presence of plaque.

Remnant lipoproteins induce endothelial plasminogen activator inhibitor-1

Remnant lipoproteins (RLPs) accumulate in type III hyperlipoproteinemia, a condition associated with significant cardiovascular morbidity. The effect of RLPs on fibrinolysis is unknown. Our aim was to study the effect of RLPs on endothelial expression of plasminogen activator inhibitor-1 (PAI-1). After 24-h culture of human aortic endothelial cells with RLPs at concentrations of 0 (control), 0.038, or 0.076 mg triglyceride/mL, postculture PAI-1 antigen concentrations were: 870 +/- 80, 1963 +/- 183 (P = 0.005), and 3551 +/- 177 ng/mL (P < 0.001), respectively. Furthermore, after 24-h incubation of endothelial cells with RLPs (0 or 0.076 mg triglyceride/mL), PAI-1 activity increased from 0.667 +/- 0.144 to 1.268 +/- 0.198 U/mL, respectively (P = 0.008) and endothelial PAI-1 mRNA increased to 2.7 +/- 0.66 that of control (P = 0.048). In conclusion, RLPs from patients with type III hyperlipoproteinemia induce endothelial cell PAI-1 expression, which may contribute to a prothrombotic state.

Efficacy of adenoviral gene transfer with manganese superoxide dismutase and endothelial nitric oxide synthase in reducing ischemia and reperfusion injury

OBJECTIVE

Both superoxide dismutase (SOD), a free radical scavenger, and nitric oxide (NO), a vasodilator with anti-inflammatory properties, have been shown to protect the myocardium from reperfusion injury. They are known to interact in vivo, the influence of which on myocardial protection has not been studied.

METHODS

Four groups of rats (n=7, per group) were subjected to experimental infarction following injections into the anterior wall of the left ventricle with adenoviral vector encoding beta-galactosidase (group A), eNOS (group B), Mn-SOD (group C) and both eNOS and MnSOD (group D). Hearts were assessed for protein expression and size of infarction.

RESULTS

Efficiency of gene up regulation was confirmed by immunostaining for eNOS and Mn-SOD, and X-gal staining for beta-gal respectively. In B and D, overexpression of eNOS was demonstrated in cardiac myocytes in addition to that in the endothelium, while in C and D, Mn-SOD was overexpressed in mainly cardiomyocytes. Infarct size was 49.7+/-4.8% in A, and was significantly reduced in the other groups (29.8+/-2.7%, 21.8+/-2.5% and 24.9+/-2.4% in B, C and D respectively).

CONCLUSION

Adenoviral gene transfer of Mn-SOD was superior to eNOS in reducing the extent of in vivo ischemia-reperfusion injury in the rat heart in our model. The effect of combined application of Mn-SOD and eNOS was not different from their individual effect.

The effects of CTLA-4Ig on acute lung allograft rejection: a comparison of intrabronchial gene therapy with systemic administration of protein

BACKGROUND

Blockade of T-cell costimulation by local delivery of an adenoviral vector encoding for CTLA-4Ig and systemic administration of the protein are compared in a rat lung allograft model.

METHODS

Left lungs of Brown Norway rats (RT1n) were transplanted into Lewis (RT11) recipients in four groups of six animals each: 1) no treatment; 2) intrabronchial transduction of donor lung with adenovirus encoding mCTLA-4Ig (adeno-mCTLA-4Ig); 3) intrabronchial transduction with empty adenovirus; and 4) intraperitoneal injection of mCTLA-4Ig. Grading of rejection, mCTLA-4Ig measurement in serum and bronchial washings, RT-PCR for virally encoded transcripts, and immunohistochemistry for mCTLA-4Ig were carried out 4 days later.

RESULTS

Intrabronchial transduction with adeno-mCTLA-4Ig resulted in detectable transgene expression in graft tissue and bronchial fluid but not in serum. Significant reduction in rejection grade (from grade 3 to 2) occurred after systemic mCTLA-4Ig but not adeno-mCTLA-4Ig transduction.

CONCLUSION

Local expression of immunomodulatory proteins can be achieved within lung allografts by intrabronchial delivery of adenoviral vector but may not significantly modify acute rejection.

Gene transfer of endothelial nitric oxide synthase to pulmonary allografts: impact on acute rejection

Experiments were designed to study whether overexpression of nitric oxide (NO) from endothelial nitric oxide synthase (eNOS) affects acute rejection. Allogenic, orthotopic single-lung transplantation was performed after transbronchial adenoviral-mediated gene transfer (3 x 10(8) pfu) of either of eNOS or beta-galactosidase to donor lungs of rats (n = 6 each). No immunosuppression was used. After 4 days, transplanted lungs were prepared for enzyme activity, cGMP and histology. Calcium-dependent NOS activity, reflecting eNOS, was greater in eNOS-transduced lungs (587 +/- 97 vs 2.1 +/- 1.4 pmol/mg protein per h, P <0.001). In contrast, calcium-independent NOS activity, reflecting iNOS, was comparable. Concentrations of cGMP were higher in eNOS-transduced lungs (13.2 +/- 2.3 vs 4.9 +/- 0.5 pmol/mg protein). Positive immunostaining for eNOS was present in pneumocytes only in eNOS-transduced lungs. No difference in histological grade of rejection was observed. eNOS gene transfer to pulmonary allografts results in a functionally active transgene product and increased NO production. Increasing NO from eNOS does not affect histogically identified acute rejection.

Gene transfer of superoxide dismutase isoforms reverses endothelial dysfunction in diabetic rabbit aorta

Increased production of oxygen free radicals is an important mechanism of endothelial dysfunction in diabetes mellitus. Our goal was to test whether adenovirus (Ad)-mediated gene transfer of copper/zinc (CuZn) or manganese superoxide dismutase (Mn SOD) improves relaxation of diabetic vessels. The aortas from 9 alloxan-induced diabetic mellitus (DM) and 16 control rabbits were used. Control and DM rings were transduced ex vivo with Ad vectors encoding Mn SOD (AdMn SOD), CuZn SOD (AdCuZn SOD), β-galactosidase (Adβgal), or diluents. In the absence of gene transfer, SOD activity was significantly increased in DM aortas. Transgene expression in DM AdCuZn SOD and DM AdMn SOD-transduced vessels was confirmed by Western blot analysis and by increased SOD activity (DM AdCuZn SOD, 76.2 ± 9.3; DM AdMn SOD, 65.2 ± 4.8; P < 0.05 vs. DM Adβgal; 50.9 ± 4.4 U/mg protein). Superoxide production was increased in DM Adβgal-transduced aorta and relaxations to acetylcholine were impaired in these vessels. Gene transfer of CuZn SOD and Mn SOD corrected both of these defects. Thus Ad-mediated gene transfer CuZn and Mn SOD to the diabetic aorta improves endothelium-dependent relaxation.

Effects of glutathione on chromium-induced DNA crosslinking and DNA polymerase arrest

Hexavalent chromium (Cr (VI)) is reduced intracellularly to Cr (V), Cr (IV) and Cr (III) by ascorbate (Asc), cysteine and glutathione (GSH). These metabolites induce a spectrum of genomic DNA damage resulting in the inhibition of DNA replication. Our previous studies have shown that treatment of DNA with Cr (III) or Cr (VI) plus Asc results in the formation of DNA-Cr-DNA crosslinks (Cr-DDC) and guanine-specific arrests of both prokaryotic and mammalian DNA polymerases. GSH not only acts as a reductant of Cr (VI) but also becomes crosslinked to DNA by Cr, thus, the focus of the present study was to examine the role of GSH in Cr-induced DNA damage and polymerase arrests. Co-incubation of Cr (III) with plasmid DNA in the presence of GSH led to the crosslinking of GSH to DNA. GSH co-treatment with Cr (III) also led to a decrease in the degree of Cr-induced DNA interstrand crosslinks relative to Cr (III) alone, without affecting total Cr DNA binding. DNA polymerase arrests were observed following treatment of DNA with Cr (III) alone, but were markedly reduced when GSH was added to the reaction mixture. Pre-formed polymerase-arresting lesions (Cr-DDC) were not removed by subsequent addition of GSH. Treatment of DNA with Cr (VI), in the presence of GSH, resulted in crosslinking of GSH to DNA, but failed to produce detectable DNA interstrand crosslinks or polymerase arrests. The inhibitory effect of GSH on Cr-induced polymerase arrest was further confirmed in human genomic DNA using quantitative PCR (QPCR) analysis. Treatment of genomic DNA with Cr (III) resulted in a marked inhibition of the amplification of a 1.6 kb target fragment of the p53 gene by Taq polymerase. This was almost completely prevented by co-treatment with GSH and Cr (III). These results indicate that Cr-induced DNA interstrand crosslinks, and not DNA-Cr-GSH crosslinks, are the principal lesions responsible for blocking DNA replication. Moreover, the formation of DNA-Cr-GSH crosslinks may actually preclude the formation of the polymerase arresting lesions.

Conditions of vector delivery improve efficiency of adenoviral-mediated gene transfer to the transplanted heart

OBJECTIVES

Conditions for ex vivo gene transfer to the transplanted heart were studied in a model of syngeneic abdominal heterotopic heart transplantation in the rat. Various methods of adenoviral-mediated gene transfer to the transplanted heart were compared.

METHODS

In the first experiment, a dose response study, an adenoviral vector encoding the beta-galactosidase gene was infused into the donor heart with the pulmonary artery open and flushed out prior to performing the transplant. In the second experiment, the effects of clamping the pulmonary artery during vector infusion and not flushing out the viral solution, resulting in vector dwell during the warm ischemia, were examined.

RESULTS

In the first experiment, gene transfer was relatively inefficient; however, transgene expression improved with increases in the vector dose (range, 1x10(7)-1x10(9)). The efficiency of gene transfer was significantly greater when the conditions of the second experiment were applied. In all models studied, cardiomyocytes and not vascular endothelial cells were the predominant cell type transduced.

CONCLUSIONS

This study indicates that the conditions of adenoviral vector delivery are critical for optimizing gene transfer in the transplant setting. In addition, intravascular administration of adenoviral vector to the donor heart results predominantly in cardiomyocyte transgene expression.

Improved efficiency of gene transfer to the transplanted lung by retrograde vascular gene delivery

Experiments were designed to evaluate the efficiency of antegrade compared to retrograde vascular gene transfection of donor lungs used for transplantation. Rat donor lungs (n = 5/group) were transduced with an adenoviral vector encoding for beta-galactosidase (AdbetaGal), either antegrade in the pulmonary artery (Group A, 3 x 10(8) pfu, Group B, 3 x 10(9) pfu) or retrograde into the pulmonary vein (Group C, 3 x 10(8) pfu), immediately after pneumoplegia. After storage at 4 degrees C for 1 h, the transduced lungs were transplanted orthotopically in syngeneic animals. The lungs were assessed for transgene expression by ELISA and X-Gal-staining at day 7 after operation. Inflammation was graded based on the extent of inflammatory cell infiltration. Transgene expression was similar between Groups A (1.7 +/- 0.7 ng/mg protein) and B (2.1 +/- 1.0 ng/mg protein). With retrograde delivery, there was a four-fold (8.3 +/- 2.6 ng/ mg protein) increase (P < 0.05) in transgene expression compared to either group A or B. In all groups, pneumocytes were transduced most frequently. The degree of inflammation correlated positively with the extent of transgene expression (r = 0.75, P < 0.01). The efficiency of vascular gene delivery to transplanted lungs can be improved by retrograde delivery of the vector via the pulmonary vein. Transgene expression predominates in pneumocytes following both antegrade and retrograde delivery. The severity of inflammation in the transplanted lung appears to correlate with the extent of transgene expression.

Superoxide anions and endothelial cell proliferation in normoglycemia and hyperglycemia

-Oxygen free radicals are believed to play a key role in cellular proliferation, and increased concentrations of these molecules have been implicated in the pathogenesis of endothelial dysfunction in diabetes mellitus. Our aim was to study the role of superoxide anions in endothelial cell proliferation under conditions of normoglycemia and hyperglycemia. Human aortic endothelial cells (HAECs) and human umbilical vein endothelial cells (HUVECs) exposed to adenoviral vectors encoding CuZnSOD (AdCuZnSOD), ss-galactosidase (Adssgal), or diluent (control) were cultured in normal glucose (NG, 5.5 mmol/L) or high glucose (HG, 28 mmol/L) medium. Cell proliferation was compared by use of [(3)H]thymidine incorporation and cell count in transduced and control cells in the setting of NG and HG. Transgene expression was detected in transduced cells by X-gal staining and by Western analysis and SOD activity assay in AdCuZnSOD-transduced cells. Superoxide production was significantly (P:<0.05) decreased in AdCuZnSOD-transduced cells cultured in both NG and HG medium. In NG, AdCuZnSOD-transduced endothelial cells had decreased proliferation compared with control cells. After 48 hours in HG, superoxide levels were increased and DNA synthesis was decreased (P:<0.05) in control and Adssgal-transduced but were not affected in AdCuZnSOD-transduced cells. In addition, after 7 days in HG, cell counts were reduced (P:<0.05) in control (73+/-2.5%) and Adssgal-transduced (75+/-3.4%) but not in AdCuZnSOD-transduced cells (89+/-3.4%). These results suggest that either a deficiency or an excess of superoxide anions inhibits endothelial cell proliferation, and the inhibitory effect of increased superoxide due to hyperglycemia can be reversed by CuZnSOD overexpression.

Effects of immunosuppressants on receptor activator of NF-kappaB ligand and osteoprotegerin production by human osteoblastic and coronary artery smooth muscle cells

Osteoporosis and vasculopathy are common after organ transplantation and have been largely attributed to the use of immunosuppressants. Osteoprotegerin (OPG) is produced by osteoblastic and arterial cells, and inhibits osteoclast functions by neutralizing receptor activator of NF-kappaB ligand (RANKL). Because OPG-deficient mice develop osteoporosis and arterial calcification, we assessed the effects of immunosuppressants on OPG and RANKL expression by human osteoblastic and coronary artery smooth muscle cells (CASMC). Cyclosporine A, rapamycin, and FK-506 decreased OPG mRNA and protein levels in undifferentiated marrow stromal cells (by 63, 44, and 68%, respectively, P < 0.001). All three immunosuppressants increased RANKL mRNA levels in these cells by 60 to 210%. In contrast to these effects on marrow stromal cells, rapamycin, which may be relatively bone-sparing, increased OPG mRNA and protein production (by 120%, P < 0.001) in mature osteoblastic cells. Cyclosporine A also decreased OPG mRNA and protein production (by 52%, P < 0.001) of CASMC. In conclusion, immunosuppressants decrease OPG mRNA and protein production and increase RANKL gene expression by marrow stromal cells, and cyclosporine suppresses OPG production in CASMC. These studies thus provide a potential mechanism for immunosuppressant-induced bone loss, and the propensity of cyclosporine A to cause vascular disease.