Characterizing left ventricular stiffness in women with signs and symptoms of ischemia with no obstructive coronary arteries

Background

Women with signs and symptoms of ischemia and no obstructive coronary arteries (INOCA) have evidence of diastolic dysfunction and are at increased risk of developing heart failure with preserved ejection fraction (HFpEF). However, mechanisms contributing to HFpEF development are poorly understood and often attributed to underlying cardiovascular risk factors.

Purpose

To compare clinical, invasive, and imaging parameters in women with suspected INOCA and various degrees of left ventricular (LV) stiffness (as measured by invasive end-diastolic pressure [EDP]/end diastolic volume [EDV]).

Methods

Women with suspected INOCA underwent invasive LV pressure-volume loop analysis at rest and coronary function testing with a Doppler wire in the left anterior descending artery. Intracoronary vasoactive substances (adenosine, acetylcholine, nitroglycerin) were infused into the left main artery, as published. Rest and adenosine stress cardiac magnetic resonance (CMR) imaging was performed to evaluate LV function, structure, perfusion, and fibrosis. Women in different tertiles of EDP/EDV ratio were compared using t-tests.

Results

A total of 62 women with complete invasive data were included; 2 did not complete CMR. Compared to the lower EDP/EDV tertile, women in the upper tertile were older, had higher ejection fraction, higher mass/volume ratio, worse diastolic function, greater aortic stiffness and worse coronary microvascular function (Table 1). Traditional cardiovascular risk factors were not significantly different.

Conclusion

Among women with INOCA, older age, coronary microvascular dysfunction, and aortic stiffness were related to greater LV stiffness at rest. Those with the highest EDP/EDV ratio had hyperdynamic LV systolic function and the smallest LV size. More work is needed to understand contribution of coronary microvascular dysfunction to HFpEF progression.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): National Institutes of HealthErika Glazer Women's Heart Health Project

Cold Pressor Testing and Sympathetic Nervous System Contribution to Ischemia with No Obstructive Coronary Artery Disease: Results from the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction Project

Study Objective

Cold Pressor Testing (CPT) is a known stimulus of the sympathetic nervous system (SNS). To better understand sympathetic contribution to coronary blood flow regulation in women with suspected ischemia and no obstructive coronary arteries (INOCA), we compared myocardial perfusion reserve during CPT stress cardiac magnetic resonance (CMR) imaging between women with suspected INOCA and reference subjects.

Design

Prospective cohort.

Setting

Academic hospital.

Participants

107 women with suspected INOCA and 21-age-matched reference women.

Interventions

CPT stress CMR was performed with measurement of myocardial perfusion reserve index (MPRI), adjusted for rate pressure product (MPRI_RPP). Invasive coronary function testing in a subset of INOCA women (n=42) evaluated for endothelial dysfunction in response to acetylcholine, including impaired coronary diameter response ≤0% and coronary blood flow response (ΔCBF) <50%.

Main Outcome Measure

MPRI_RPP.

Results

Compared to reference women, the INOCA group demonstrated higher resting RPP (p=0.005) and CPT MPRI_RPP (1.09±0.36 vs 0.83±0.18, p=0.002). Furthermore, INOCA women with impaired ΔCBF (n=23) had higher CPT MPRI_RPP (p=0.044) compared to reference women despite lower left ventricular ejection fraction (64±7 % vs 69±2 %, p=0.005) and mass-to-volume ratio (0.79±0.15 vs 0.62±0.09, p<0.0001). These differences in CPT MPRI_RPP did not persist after adjusting for age, body mass index, and history of hypertension. CPT MPRI_RPP among INOCA women did not differ based on defined acetylcholine responses.

Conclusions

Myocardial perfusion reserve to CPT stress is greater among women with INOCA compared to reference subjects. CPT induced a higher MPRI_RPP also in women with coronary endothelial dysfunction, suggesting a greater contribution of the SNS to coronary flow than endothelial dysfunction. Further investigation in a larger cohort is needed.

Normalisation of hypoxaemia following successful percutaneous closure of a bidirectional shunting secundum atrial septal defect without pulmonary hypertension in a patient with severe non-ischaemic cardiomyopathy and refractory ventricular tachycardia

Atrial septal defects (ASD) are an uncommon cause of dyspnoea. A high index of suspicion is required, and further investigation should be prompted in patients with unexplained hypoxaemia, particularly those with pulmonary hypertension. Hypoxic ASD without pulmonary hypertension are rare, and only a handful of cases have been published. We present a middle-aged man with progressive dyspnoea with a successfully closed ASD without pulmonary hypertension caused by elevated right ventricular pressures secondary to an idiopathic cardiomyopathy.

Pulmonary arterial hypertension associated with the use of interferon therapy for chronic hepatitis C infection complicated by extrinsic left main coronary artery compression

Interferon-alpha treatment is a rare cause of pulmonary arterial hypertension (PAH). We report a case of a 43-year-old man treated for chronic hepatitis C infection complicated by decompensated right heart failure diagnosed with PAH and external coronary artery compression secondary to a dilated pulmonary trunk. The novel complication of extrinsic coronary artery compression should be considered in PAH patients presenting with chest pain or acute coronary syndrome. Establishing a diagnosis has clinical value as pulmonary vasodilator therapy may improve symptoms.

The influence of salinity and dissolved organic carbon on the toxicity of copper to the estuarine copepod, Eurytemora affinis

The objectives of this study were to determine the influence of salinity (2.5, 5, 15, and 25 ppt) at dissolved organic carbon (DOC) concentrations of 1.3-3.3 mg/L and DOC concentrations of 2, 4, 6, and 8 mg/L at a fixed salinity of 10 ppt on the acute toxicity (96-h LC50s) of copper to the sensitive estuarine copepod, Eurytemora affinis. For both salinity and DOC experiments, various other chemical constituents such as DOC, Ca2+, Cl(-), Mg2+, Na+, K+, SO4 (2-) , hardness, alkalinity, salinity, pH, temperature, and dissolved oxygen were measured at selected copper concentrations at test initiation and test termination. Dissolved copper, copper speciation, and organic copper complexation were measured at various test conditions during the salinity and DOC experiments. Ninety-six-hour dissolved copper LC50 values for the four salinities ranged from 58 microg/L (25 ppt) to 104 microg/L (5 ppt) with intermediate values of 71 microg/L (2.5 ppt) and 68 microg/L (15 ppt). The 58, 68, and 71 microg/L LC50 values were not significantly different. Copper LC50 values at 5 ppt were higher than at both 15 and 25 ppt. The isosmotic salinity of E. affinis is approximately 5-10 ppt, which was a likely factor for why the LC50 value increased for copper at 5 ppt. The dissolved copper 96-h LC50s for E. affinis increased from 76 to 166 microg/L as DOC increased from 2 to 8 mg/L. This result is not surprising and is consistent with reported values for other saltwater species.

Alloplastic lip enhancement

Alloplastic lip augmentation can be safe, effective, and predictable when properly executed. The author describes his surgical technique, which evolved from the performance of more than 432 lip augmentation procedures, and focuses in detail on the materials he uses to achieve the best results. (Aesthetic Surg J 2001;21:445-449.).

Does the presence of thrombus seen on a coronary angiogram affect the outcome after percutaneous coronary angioplasty? An Angiographic Trials Pool data experience

OBJECTIVES

This study aimed to determine whether pre-existing angiographic thrombus was associated with adverse in-hospital and six-month outcomes after percutaneous coronary interventions.

BACKGROUND

There are conflicting data about whether pre-existing thrombus is an independent predictor of adverse in-hospital and short-term outcome after coronary interventions.

METHODS

The Angiographic Trials Pool, a data set derived from eight prospective randomized trials, was analyzed. The study population consisted of 7,917 patients who underwent coronary interventions between 1986 and 1995. Two trials were excluded because they did not collect information regarding thrombus. Patients from the other six trials were divided on the basis of the presence or absence of thrombus.

RESULTS

In patients with (n = 2,752) and without (5,165) thrombus, in-hospital mortality following angioplasty was low (0.8 vs. 0.6%, p = 0.207). Several adverse outcomes were higher in patients with thrombus: death/myocardial infarction (8.4 vs. 5.5%, p < or = 0.001), in-hospital abrupt closure (5.9 vs. 3.9%, p < or = 0.001) and an in-hospital composite of death, myocardial infarction and/or repeat revascularization (15.4 vs. 11.2%, p < or = 0.001). Six-month mortality was low and comparable between the two groups (2.1 vs. 1.8%, p = 0.34), but the incidence of six-month death/myocardial infarction was higher in patients with thrombus (11.7 vs. 8.7%, p < or = 0.0001).

CONCLUSIONS

Percutaneous coronary angioplasty can be performed with low mortality in patients with pre-existing thrombus, although these patients are at higher risk of in-hospital and six-month death/myocardial infarction. Continued efforts are required to optimize the outcome in these high risk patients.

Design of the therapeutic angiogenesis with recombinant fibroblast growth factor-2 for intermittent claudication (TRAFFIC) trial

The Therapeutic Angiogenesis With Recombinant Fibroblast Growth Factor-2 for Intermittent Claudication (TRAFFIC) is a large, randomized, placebo-controlled, regimen-finding trial of intra-arterial recombinant fibroblast growth factor-2 in patients with intermittent claudication. This report describes the major design considerations and end points in TRAFFIC.

Syphilitic aortitis

A case of syphilitic aortitis, complicated by bilateral coronary ostial stenosis, in a 40-year-old man is described. Treatment included coronary artery bypass grafting and a drug regimen of penicillin. At 3-month follow-up, an exercise stress test revealed no signs of ischemia.

Lack of progress in cardiogenic shock: lessons from the GUSTO trials

AIMS

We used the GUSTO-I and GUSTO-III databases to evaluate our performance in treating cardiogenic shock patients over much of the 1990s.

METHODS AND RESULTS

GUSTO-I (1990-1993) and GUSTO-III (1995-1997) prospectively identified all patients with cardiogenic shock complicating acute myocardial infarction. Demographics, clinical presentation and outcomes for cardiogenic shock patients in the two trials were compared. Only patients enrolled with cardiogenic shock in countries common to both trials were included in these analysis. The 695 patients with cardiogenic shock in GUSTO-III were compared with the 2814 patients with cardiogenic shock in GUSTO-I. GUSTO-III patients were older (P=0.0001) and more likely to be diabetic (P=0.009) and hypertensive (P=0.025). They had a higher Killip class (P=0.002) and significantly greater index anterior infarction than cardiogenic shock patients enrolled in GUSTO-I. Time to treatment, presentation heart rate, and diastolic blood pressure were similar; however, systolic blood pressure at presentation was higher among GUSTO-III patients (P=0.002). Rates of coronary angiography, pulmonary artery catheterization, and mechanical ventilation declined in GUSTO-III compared with GUSTO-I (P=0.001); rates of angioplasty and bypass surgery were similar. Cardiogenic shock mortality in GUSTO-III was significantly higher than in GUSTO-I (62 vs 54%, P=0.001), as were rates of reinfarction (14 vs 11%, P=0.013) and recurrent ischaemia (35 vs 27%, P=0.00001). Mortality at non-U.S. sites (68 and 64%) was higher than at U.S. sites (53 and 50%) in both GUSTO-I and GUSTO-III studies, respectively. Angioplasty, bypass surgery, and balloon pump rates were lower for non-U.S. patients.

CONCLUSIONS

Cardiogenic shock continues to be associated with high mortality in thrombolytic-treated patients. Lower mortality observed in the U.S.A. supports consideration for percutaneous and surgical revascularization.

Low-dose daily subcutaneous interleukin-2 in combination with highly active antiretroviral therapy in HIV+ patients: a randomized controlled trial

PURPOSE

Previous studies with intermittent interleukin-2 (IL-2) therapy using intermediate and high levels of IL-2 have demonstrated significant increases in the CD4 + T cell count in HIV-infected patients. Intermittent regimens are amenable to outpatient use, but severe adverse events are frequently experienced with intermediate- and high-dose levels of IL-2. Therefore in this study, the effect of daily, subcutaneous low-dose IL-2 therapy on safety and immunological endpoints was investigated to determine whether immunological benefit could be achieved without toxicity in HIV-infected patients also receiving highly active antiretroviral therapy (HAART).

METHOD

A total of 115 patients were enrolled in the trial. Fifty-six asymptomatic HIV-infected patients who had CD4 + T cell counts less than 300 cells/microL at screening and a stable HIV viral load received low-dose IL-2 (1.2 million IU [MIU]/m 2 beginning dose) once daily in conjunction with HAART (IL-2 group). Fifty-nine patients received HAART alone (control group).

RESULTS

A dramatic effect of IL-2 on the natural killer (NK) cell population was observed with mean increases of 156 cells/microL in the IL-2 group compared to 19.93 cells/microL in the control group (p <.001). Additionally, IL-2-treated patients experienced a statistically significant increase in the mean percentage of CD4 + T cells (3.52% increase) when compared to control patients (1.33% increase) (p <.001). The expanded CD4 + T cell population was primarily of the naive phenotype, with mean increases of 4.53% for the IL-2 group and 0.31% for the control group (p <.001 for between-group difference). In addition, a higher proportion of IL-2-treated patients (67%) compared to control patients (33%) achieved increases of greater than 50% in the CD4+ T cell count (p =.08). Adverse events of grade 3 or grade 4 toxicity were infrequent in the current study and were substantially lower by comparison to those in studies of intermittent dose IL-2 therapy. Also, negligible changes in the HIV viral load from baseline to final measurement were observed in both groups. A trend toward a reduced number of modifications of antiretroviral therapy was apparent in the IL-2 group when compared to control patients.

CONCLUSION

Daily, low-dose subcutaneous IL-2 therapy in conjunction with HAART is safe and well tolerated and is effective in expanding lymphocyte cell types including NK cells and naive T cells in individuals who have <300 CD4+ T cells.

Adenoviral-mediated transfer of the TNF-related apoptosis-inducing ligand/Apo-2 ligand gene induces tumor cell apoptosis

TNF-related apoptosis-inducing ligand (TRAIL) is a member of the TNF superfamily of cytokines that induces apoptosis in a variety of cancer cells. The results presented in this study demonstrate that introduction of the human TRAIL gene into TRAIL-sensitive tumor cells using an adenoviral vector leads to the rapid production and expression of TRAIL protein, and subsequent death of the tumor cells. Tumor cell death was mediated by an apoptotic mechanism, as evidenced by the activation of caspase-8, cleavage of poly(ADP-ribose) polymerase, binding of annexin V, and inhibition by caspase inhibitor zVAD-fmk. These results define a novel method of using TRAIL as an antitumor therapeutic, and suggest the potential use for an adenovirus-encoding TRAIL as a method of gene therapy for numerous cancer types in vivo.

A simple method for the rapid generation of recombinant adenovirus vectors

Recombinant adenoviruses are useful vectors for basic research. When the vectors are used for delineating protein function, several viruses, each containing a mutated version of the transgene are compared at the same time. However, methods to generate multiple vectors simultaneously within a short time period are cumbersome. In this report, we show that a novel backbone plasmid, when cotransfected with routinely used shuttle vectors into HEK293 cells allowed for production of recombinant viruses in an average of 14 days. The recombinant viruses had no detectable wild-type virus contamination by A549 plaque assay and only three to 300 E1a copies per 109 adenovirus genomes by a sensitive PCR-based assay. Further culturing or serial amplification did not result in wild-type revertants nor did cultures show increased levels of E1a copy number by quantitative PCR. Thus, recombinant adenovirus vectors can be produced very simply, rapidly and with little to no contaminating wild-type particles. This system should facilitate the generation of multiple genetic variants by eliminating the need for time-consuming plaque purification and the need to manipulate and screen very large plasmids. We call this the RAPAd.I system.

Ongoing open-label trials of triple therapy with stavudine and lamivudine or stavudine and didanosine plus nelfinavir

The VZN and ZEN studies are non-comparative trials assessing triple combination therapy comprising thymidine and non-thymidine analogue nucleoside reverse transcriptase inhibitors plus a protease inhibitor. Preliminary data are available for the VZN study and recruitment for the ZEN study is underway.

Systemic hyperosmolality improves beta-glucuronidase distribution and pathology in murine MPS VII brain following intraventricular gene transfer

Mucopolysaccharidosis VII, a classical lysosomal storage disease, is caused by deficiency of the enzyme beta-glucuronidase. Central nervous system (CNS) manifestations are severe with accumulations of storage vacuoles in all cell types. Intraventricular gene transfer can lead to transduction of the ependyma, with production and secretion of beta-glucuronidase into the cerebral spinal fluid and underlying cortex resulting in reversal of disease pathology restricted to the periventricular areas. We tested if systemic hyperosmolality would increase the distribution of beta-glucuronidase in brain parenchyma after intraventricular virus injection. Mice were administered mannitol, intraperitoneally, 20 days after gene transfer and 1 day prior to sacrifice. Mannitol-induced systemic hyperosmolality caused a marked penetration of beta-glucuronidase into the brain parenchyma. If mannitol was administered at the time of the intraventricular injection of virus, there was penetration of vector across the ependymal cell layer, with infection of cells in the subependymal region. This also resulted in increased beta-glucuronidase activity throughout the brain. Sections of brains from beta-glucuronidase-deficient mice showed correction of cellular pathology in the subependymal region plus cortical structures away from the ventricular wall. These data indicate that virus-mediated gene transfer to the brain via the ventricles, coupled with systemic mannitol administration, can lead to extensive CNS distribution of beta-glucuronidase with concomitant correction of the storage defect. Our findings have positive therapeutic implications for the treatment of CNS disorders with gene transfer vectors and recombinant proteins.

Extensive beta-glucuronidase activity in murine central nervous system after adenovirus-mediated gene transfer to brain

Mucopolysaccharidosis type VII (MPS VII), caused by beta-glucuronidase deficiency, is a classic lysosomal storage disease. In the central nervous system (CNS), there is widespread pathology with distention of vacuoles in neurons and glia. An approach to therapy for MPS VII would require extensive delivery of enzyme to the CNS and subsequent uptake by the affected cells. In this study we show that intrastriatal injection of recombinant adenovirus encoding beta-glucuronidase (Ad betagluc) to MPS VII or wild-type mice results in focal, intense beta-glucuronidase mRNA expression near the injection site. Further, histochemical staining for enzyme activity showed that beta-glucuronidase activity extended well beyond transduced cells. Activity was detected throughout the ipsilateral striatum as well as in the corpus callosum, ventricles, and bilateral neocortex. Similarly, after injection into the right lateral ventricle or cisterna magna, enzyme activity was present in the ependymal cells of the ventricles, in the subarachnoid spaces, and also in the underlying cortex (150-500 microm from ependyma). The distribution of enzyme was most extensive 21 days after gene transfer to normal mouse brain, with more than 50% of the hemisphere positive for beta-glucuronidase activity. Eighty-four days after adenovirus injection a substantial level of enzyme expression remained (>40% of hemisphere positive for beta-glucuronidase activity). Histological sections from striatum of beta-glucuronidase-deficient mice injected with Ad betagluc showed a marked reduction in the number of distended vacuoles in both neurons and glia, as compared with uninjected striatum. Importantly, correction was noted in both hemispheres. Our finding that a relatively small number of transduced cells produce enzyme that reaches a large proportion of the CNS has favorable implications in developing direct gene transfer therapies for lysosomal storage disorders.

Endoscopic malar/midface suspension procedure

Aging in the midface area is seen with ptosis of the malar tissues, hollowing of the infraorbital area, deepening of the nasolabial and mandibular labial folds, and increased jowling. Some of these aging changes are usually not corrected by a standard SMAS face lift. An endoscope-dependent technique was created specifically to address the midface area. The midface tissues are elevated and released in a subperiosteal manner and then suspended to a higher position after endoscopic dissection of the temporal area. The tissues are repositioned to a higher position on the malar area with softening of the nasolabial fold, decreased jowls, and recreation of the desired youthful fullness in the malar and infraorbital area. This procedure can be combined easily with other facial procedures such as rhytidectomy, neck lift, temple lift, and laser resurfacing when indicated. More than 200 procedures have been completed in the last 22 months. This report presents the surgical technique with early follow-up results.

Prognostic value of congestive heart failure history in patients undergoing percutaneous coronary interventions

OBJECTIVES

We sought to determine the prognostic significance of a history of congestive heart failure above that provided by baseline ejection fraction in patients undergoing percutaneous coronary interventions.

BACKGROUND

Left ventricular function is a known predictor of survival in patients with coronary artery disease, as is a history of congestive heart failure. The contribution of heart failure history independent of left ventricular function is unknown.

METHODS

Data were pooled from four interventional trials and the Duke University database. The combined dataset included 5,260 patients undergoing percutaneous interventions, 334 with and 4,926 without a history of heart failure. Patients were defined by the treating physician as having a clinical history of heart failure at the time of enrollment.

RESULTS

The 30-day and 6-month mortality were higher in patients with a clinical history of congestive heart failure than in those without such a history (2% vs. <1%, p=0.002 at 30 days, 5% vs. 1%, p=0.001 at 6 months). Heart failure history did not influence the incidence of myocardial infarction, use of angioplasty or the use of bypass surgery during follow-up. Multivariable analysis revealed that heart failure history added significantly to ejection fraction in predicting intermediate-term (6-month) mortality (p=0.01). Stepwise logistic regression also revealed heart failure history to be an independent predictor of 6-month mortality (odds risk 1.9, 95% confidence interval 1.1 to 3.5).

CONCLUSIONS

A clinical history of congestive heart failure is associated with increased early and intermediate-term mortality in patients undergoing percutaneous revascularization. Congestive heart failure history appears to provide prognostic information independent of that available from a patient's left ventricular function. These findings suggest that patients with a clinical history of congestive heart failure who undergo a percutaneous intervention should be closely monitored, especially those with the lowest ejection fractions.

Functional rescue of the sarcoglycan complex in the BIO 14.6 hamster using delta-sarcoglycan gene transfer

Four types of limb-girdle muscular dystrophy (LGMD) are known to be caused by mutations in distinct sarcoglycan genes. The BIO 14.6 hamster is a model for sarcoglycan-deficient LGMD with a deletion in the delta-sarcoglycan (delta-SG) gene. We investigated the function of the sarcoglycan complex and the feasibility of sarcoglycan gene transfer for LGMD using a recombinant delta-SG adenovirus in the BIO 14.6 hamster. We demonstrate extensive long-term expression of delta-sarcoglycan and rescue of the entire sarcoglycan complex, as well as restored stable association of alpha-dystroglycan with the sarcolemma. Importantly, muscle fibers expressing delta-sarcoglycan lack morphological markers of muscular dystrophy and exhibit restored plasma membrane integrity. In summary, the sarcoglycan complex is requisite for the maintenance of sarcolemmal integrity, and primary mutations in individual sarcoglycan components can be corrected in vivo.

A single-dose study to assess the penetration of stavudine into human cerebrospinal fluid in adults

Penetration of stavudine into the cerebrospinal fluid (CSF) was studied in healthy humans. In this open, randomized study, a single oral dose of 40 mg of stavudine was given to 12 fasting volunteers > or = 18 years of age. Subjects were divided into three groups based on the time of CSF sampling (i.e., 0.75-1.25, 2-3, or 4-5 hours after dosing). Blood samples were collected over an 8-hour period after dosing and included a sample simultaneous with CSF collection to permit an estimate of CSF : plasma ratios. Stavudine concentrations in plasma and CSF were determined by a validated high-performance liquid chromatography method. Repeated measurements of vital signs, physical examination, and clinical laboratory tests indicated that the stavudine dose was well tolerated. CSF levels were not detected 0.75 to 1.25 hours after dosing. Thereafter, levels were detected in the CSF of five subjects; the mean concentration was 61 ng/ml. The mean CSF: plasma ratio increased with time, from 0.16 at 2 to 3 hours postdose in one subject to 0.40 at 4 to 5 hours postdose in four subjects. In conclusion, the mean stavudine concentration of 61 ng/ml achieved in the CSF of five subjects exceeds the ED50 of clinical isolates of HIV (230 nM, 52 ng/ml).

Relationship between diabetes mellitus and long-term survival after coronary bypass and angioplasty

BACKGROUND

Recent subgroup analyses of randomized trials have suggested that percutaneous intervention in diabetic patients with multivessel disease results in higher mortality than coronary artery bypass graft surgery (CABG). We studied the relationship between diabetes and survival after revascularization in a large prospective cohort of patients with multivessel coronary artery disease.

METHODS AND RESULTS

By analyzing data for 3220 patients (24% diabetic) with symptomatic two- or three-vessel coronary disease who were undergoing percutaneous transluminal coronary angioplasty (PTCA) or CABG at Duke University Medical Center between 1984 and 1990, we found that at 5 years, unadjusted survival in the group of patients undergoing CABG was 74% in diabetics and 86% in nondiabetics. Similarly, 5-year survival among PTCA patients was 76% in diabetics and 88% in patients without diabetes. After adjustment for baseline characteristics, diabetic patients receiving either PTCA or CABG had significantly poorer survival than nondiabetics (chi2=43.56, P<.0001). Unlike previous studies, however, there was no significant differential effect of diabetes on outcome between patients treated with PTCA and those treated with CABG (chi2=0.01, P=.91).

CONCLUSIONS

Although diabetes was associated with a worse long-term outcome after both PTCA and CABG in patients with multivessel coronary artery disease, the effect of diabetes on prognosis was similar in both treatment groups. Thus, our findings support the concept that the choice of initial revascularization strategy should not be based exclusively on a history of diabetes but rather should rely on other factors, such as angiographic suitability and clinical status.

Use of intraaortic balloon counterpulsation in patients presenting with cardiogenic shock: observations from the GUSTO-I Study. Global Utilization of Streptokinase and TPA for Occluded Coronary Arteries

OBJECTIVES

We sought to examine the use, complications and outcomes with early intraaortic balloon counterpulsation (IABP) in patients presenting with cardiogenic shock complicating acute myocardial infarction and treated with thrombolytic therapy.

BACKGROUND

The use of IABP in patients with cardiogenic shock is widely accepted; however, there is a paucity of information on the use of this technique in patients with cardiogenic shock who are treated with thrombolytic therapy.

METHODS

Patients who presented within 6 h of chest pain onset were randomized to one of four thrombolytic regimens. Cardiogenic shock was not an exclusion criterion, and data for these patients were prospectively collected. Patients presenting with shock were classified into early IABP (insertion within one calendar day of enrollment) or no IABP (insertion on or after day 2 or never).

RESULTS

There were 68 (22%) IABP placements in 310 patients presenting with shock. Early IABP use occurred in 62 patients (20%) and none in 248 (80%). Most IABP use occurred in the United States (59 of 68 IABP placements) involving 32% of U.S. patients presenting with shock. Despite more adverse events in the early IABP group and more episodes of moderate bleeding, this cohort showed a trend toward lower 30-day and 1-year mortality rates.

CONCLUSIONS

IABP appears to be underutilized in patients presenting with cardiogenic shock, both within and outside the United States. Early IABP institution is associated with an increased risk of bleeding and adverse events but a trend toward lower 30-day and 1-year all-cause mortality.

Effect of fluconazole on the steady-state pharmacokinetics of delavirdine in human immunodeficiency virus-positive patients

Fluconazole, an inhibitor of certain human cytochrome P-450 isozymes, is used for the prevention and treatment of a broad range of fungal infections that predominantly affect immunocompromised individuals. This study evaluated the influence of fluconazole on the steady-state pharmacokinetics of delavirdine, a nonnucleoside inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase, in 13 HIV-1-infected patients with CD4 counts ranging from 186 to 480/mm3. Both the control group (n = 5) and the fluconazole group (n = 8) received 300 mg of delavirdine mesylate every 8 h for 30 days; subjects in the fluconazole group took a 400-mg, once-daily dose of fluconazole on study days 16 to 30. Harvested plasma from serial blood samples collected on days 15, 16, and 30 were assayed for concentrations of delavirdine and its N-desalkyl metabolite by a reversed-phase high-pressure liquid chromatography (HPLC) method. Blood samples obtained on days 16 and 30 were also assayed for fluconazole by HPLC. Delavirdine mesylate alone and in combination with fluconazole was well tolerated. There were no significant differences (P > 0.16) in delavirdine pharmacokinetic parameters between treatment groups on day 15 or day 30. After coadministration of fluconazole and delavirdine mesylate for 2 weeks (day 30), no significant differences (P > 0.058) were observed in any delavirdine pharmacokinetic parameters relative to those after receiving delavirdine mesylate alone (day 15) after in the fluconazole group. Fluconazole pharmacokinetic parameters were similar to those previously reported for healthy volunteers and HIV-positive patients. On the basis of these findings, fluconazole and delavirdine mesylate may be taken concurrently without adjustment of the dose of either drug.

Coronary artery angioplasty with a helical autoperfusion balloon catheter

The initial in-hospital and long-term clinical experience with a helical autoperfusion balloon catheter in the treatment of coronary artery disease is reported. This new catheter design allows blood to flow passively around the inflated balloon through a protected helical channel molded into the balloon surface. Twelve consecutive patients underwent PTCA. Continuous ST monitoring, heart rate, average peak distal coronary blood flow velocity (APV), coronary blood flow (CBF), dP/dt and systemic and pulmonary arterial pressures were determined during PTCA. During balloon inflation there were no hemodynamic changes, TIMI flow was 1.7 +/- 0.8, and APV was 39% of baseline. Luminal diameter stenosis improved from 61 +/- 17 to 29 +/- 13% (P < 0.05) following PTCA. Mean continuous inflation duration was 385 +/- 215 sec and 6/12 patients had > or = 7.5-min inflations. There were no in-hospital adverse cardiac events. One patient developed recurrent angina during 8 mo of follow-up and underwent successful PTCA of a restenotic lesion. We conclude that human plaques can be successfully dilated with a helical balloon catheter that provides autoperfusion and the ability to perform prolonged inflations with hemodynamic stability. A comparison of this PTCA catheter with standard balloon catheters is warranted.

New concept in coronary angioplasty: dilatation with a helical balloon that allows simultaneous autoperfusion

These preclinical studies investigate a new concept in coronary angioplasty and balloon catheter technology (the P100 catheter). The study sought to evaluate the morphology of experimental coronary arterial plaques dilated with the P100 in comparison to standard balloons, to determine the in vitro flow rates occurring during the inflation of the P100 in comparison to available perfusion catheters, and to assess the in vivo coronary flow velocity and the presence of ischemia during prolonged inflations with the P100. The development of myocardial ischemia is a major limitation of standard balloon angioplasty. To limit ischemia, autoperfusion catheters have been developed, in which blood flows through the balloon in the central catheter shaft. However, as the flow lumen profile is reduced to enhance the performance of these devices, so is the accompanying flow. An angioplasty catheter was designed to evaluate the feasibility of continuous autoperfusion around the dilatation balloon. The balloon surface was engineered to develop a helical trough for blood flow to occur during inflation. Arterial plaque morphology following angioplasty with the P100 (n = 8) and with standard balloons (n = 8) was evaluated in a swine model. In vitro flow rates during inflation of the P100 and available perfusion catheters were determined using 33% glycerol solution. In vivo coronary flow velocity was determined with a Doppler-tipped wire during 60-min continuous inflations with the P100, and 15-sec inflations with a standard balloon in 12 vessel segments in 7 dogs; using 3.0-3.5-mm-diameter balloons. All lesions were successfully dilated (< 50% luminal diameter stenosis) with the P100 and standard balloons. There were no morphologic differences in plaques dilated with P100 compared to standard balloons. In vitro flow rates with conventional 3.0-mm balloon perfusion catheters ranged from 27.1 +/- 2.1 ml/min (RX Flowtrack) to 38.7 +/- 0.9 ml/min (Stack Perfusion), P < .05. Flow with the P100 ranged from 54.8 +/- 4.3 ml/min (2.5-mm balloon) to 103.2 +/- 4.5 ml/min (3.5-mm balloon), P < .05. Distal average peak coronary flow velocity during prolonged P100 inflations varied from 69 +/- 7% of baseline at 5 min to 83 +/- 8% of baseline at 40 min, with an upward trend in velocity the longer the balloon was inflated. Hemodynamics remained stable. Experimental plaques are successfully dilated with a helical balloon by a mechanism that appears similar to the dilatation mechanism of standard balloons. These preclinical studies show that angioplasty and autoperfusion can be accomplished by a balloon that does not have complete surface area contact with the vessel wall. A gap created by the helix can thus provide a conduit for blood flow. Clinical studies will determine whether this innovation, which alters the tubular geometry of current angioplasty balloons, will provide autoperfusion and equivalent dilatation effects in human.

The effect of intra-aortic balloon counterpulsation on coronary blood flow velocity distal to coronary artery stenoses

Despite the accepted clinical benefit of intra-aortic balloon counterpulsation (IABC), the physiologic explanation for its benefit remains controversial. Indirect methods of measuring coronary blood flow during IABC in obstructive coronary disease have yielded conflicting results. The direct measurement of coronary blood flow velocity distal to sites of stenoses by methods that do not potentially impede flow has not been previously reported. The aim of our study was to determine the effect of IABC on coronary blood flow velocity distal to a coronary stenosis by employing a method that would not impede flow through the stenosis. In an open-chest canine model, phasic and mean left anterior descending coronary artery flow velocities distal to varying degrees of stenosis were continuously measured by an epicardial Doppler probe with and without counterpulsation. All hemodynamic parameters were recorded in the absence of stenosis (n = 5) and the presence of subcritical (n = 5) and critical stenoses (n = 5). Heart rate was not affected by counterpulsation. Systolic blood pressure and rate-pressure product declined at all times with IABC. Compared to baseline, peak aortic diastolic pressure was augmented by an average of 24 mm Hg during IABC (p < 0.05). However, mean coronary artery flow velocities remained unchanged (101, 103 and 98% of baseline for no stenosis, subcritical stenosis and critical stenosis, respectively; p > 0.05 compared to baseline). Peak diastolic flow velocities were 106, 102 and 96% of baseline for no stenosis, subcritical and critical stenoses, respectively (p > 0.05). Despite the augmentation of peak diastolic pressure, distal coronary blood flow velocity was not increased by IABC in this canine model, irrespective of the severity of proximal coronary stenosis. These data suggest that augmentation of coronary artery flow distal to sites of stenoses is not primarily responsible for the clinical benefit observed when IABC is used in the setting of obstructive coronary artery disease. The reduction in afterload and myocardial oxygen demand observed in this model agrees with previous studies and likely accounts, at least in part, for the positive clinical results with IABC.

Clinical and molecular pathological features of severe childhood autosomal recessive muscular dystrophy in Saudi Arabia

The clinical, biochemical and histochemical features of 14 patients (nine females and five males) with severe childhood autosomal recessive muscular dystrophy (SCARMD) seen at a tertiary hospital in Riyadh from 1982 to 1993 are described. Onset was at 3 to 9 (median 3) years and four of five children aged > 12 years lost ambulation. Five of the eight pairs of parents were closely consanguineous. The mean creatine kinase was 20 times the upper normal limit. Histochemistry of muscle showed dystrophic features in all cases, and dystrophin was positive in all cases examined (N = 6). Three patients (two girls and a boy) were deficient in adhalin, the 50-kDa dystorphin-associated glycoprotein. A boy aged 13 years had rapidly progressing disease. Another boy of the same age (from a family characterized by early onset and slower progression) had normal dystrophin and adhalin. The clinical features conformed with previous observations from Sudan, North Africa and Qatar in the Arabian Peninsula. The disease is common in Saudi Arabia and seems to be more prevalent than Duchenne muscular dystrophy.

Ganciclovir absolute bioavailability and steady-state pharmacokinetics after oral administration of two 3000-mg/d dosing regimens in human immunodeficiency virus- and cytomegalovirus-seropositive patients

Oral ganciclovir has recently been approved for use in long-term maintenance therapy in the treatment of cytomegalovirus (CMV) retinitis in immunocompromised patients. Although oral ganciclovir at a dose of 3,000 mg/d is moderately less effective than intravenous (i.v.) ganciclovir maintenance therapy (5 mg/kg as a 1-hour i.v. infusion every 24 hours), convenience and practicality make oral maintenance therapy desirable. Two dosing regimens--1,000 mg three times daily (TID) and 500 mg every 3 hours (six times daily)--have been shown to be efficacious. Eighteen human immunodeficiency virus- and CMV-seropositive patients participated in a three-way, open-label, crossover study to evaluate the steady-state pharmacokinetics and absolute bioavailability of the two oral regimens compared with the i.v. regimen. Sixteen patients completed the study and received ganciclovir as a single 5-mg/kg i.v. infusion over 1 hour, 500 mg orally every 3 hours while awake (six times daily) for 3 days, and 1,000 mg TID orally for 3 days. Blood samples were obtained over a 24-hour period after the single i.v. dose and on day 3 of the oral dosing regimens. Mean peak serum concentrations were 8.27, 1.02, and 1.18 micrograms/mL for the i.v. and oral regimens, respectively. Twenty-four-hour area under the curve (AUC) for the oral regimens--500 mg every 3 hours and 1,000 mg TID--were 15.9 and 15.4 micrograms.h/mL, respectively, as compared with a total AUC of 22.1 micrograms.h/mL for the single i.v. dose. The absolute bioavailabilities for the two oral regimens were 8.84% and 8.53%, respectively. The extent of ganciclovir absorption, peak concentrations, and average concentration at steady state were not statistically different between the two oral regimens. The peak-to-trough concentration ratio (Cmax:Cmin) was greater for the 1,000-mg TID regimen than for the regimen of 500 mg every 3 hours (5.35 vs 3.81 [P < 0.01]). Both oral regimens resulted in concentrations in the range of the concentration that inhibits 50% of most human CMV isolates. Because both oral regimens provide equivalent absorption, the 1,000-mg TID regimen may be preferred for the convenience and potentially greater compliance associated with fewer daily doses.

Absence of the skeletal muscle sarcolemma chloride channel ClC-1 in myotonic mice

The voltage-dependent chloride channel ClC-1 stabilizes resting membrane potential in skeletal muscle. Mutations in the ClC-1 gene are responsible for both human autosomal recessive generalized myotonia and autosomal dominant myotonia congenita. To understand the tissue distribution and subcellular localization of ClC-1 and to evaluate its role in an animal model of myotonia, antibodies were raised against the carboxyl terminus of this protein. Expression of the 130-kDa ClC-1 protein is unique to skeletal muscle, consistent with its mRNA tissue distribution. Immunolocalization shows prominent ClC-1 antigen in the sarcolemma of both type I and II muscle fibers. Sarcolemma localization is confirmed by Western analysis of skeletal muscle subcellular fractions. The ADR myotonic mouse (phenotype ADR, genotype adr/adr), in which defective ClC-1 mRNA has been identified, is shown here to be absent in ClC-1 protein expression, whereas other skeletal muscle sarcolemma protein expression appears normal. Immunohistochemistry of skeletal muscle from ADR and other mouse models of human muscle disease demonstrate that the absence of ClC-1 chloride channel is a defect specific to ADR mice.

Correlation of doxorubicin footprints with deletion endpoints in lacO of E. coli

This study explored the possibility that the sequence location of doxorubicin-induced deletion endpoints might relate to DNA structural alterations caused by doxorubicin binding to DNA. The 3'-OH endpoints of doxorubicin-induced deletions terminating in the 35-bp region of lacO appear to distribute differently from spontaneous deletion endpoints. Doxorubicin-induced deletions focus in the 26-bp palindrome which is separated by a 9-bp region with no reverse complementary, whereas spontaneous deletion 3'-OH endpoints are found distributed throughout the operator region. In order to explore the mechanism of deletion induction by doxorubicin, drug footprinting studies were carried out with DNA labeled at the 5' end of each of the complementary DNA strands encompassed by lacO. Doxorubicin protected the 9-bp region between the palindromic sequences from DNase I cutting and caused enhanced DNase I cleavage at symmetrical sites in the palindrome, which were inherently resistant to the nuclease in the absence of the drug. These symmetrical sites also define regions in which the occurrence of deletion endpoints is enhanced 6-fold in the presence of doxorubicin. This enhanced cutting and mutation occur in regions of the palindrome that are flanked by expected doxorubicin binding sites, but are not themselves binding sites of the drug. Similarly, other sites where the frequency of deletion endpoints increased in response to doxorubicin occurred directly adjacent to regions where doxorubicin appeared to inhibit cutting by DNase I. These results suggest that the binding of doxorubicin in the palindrome directs both the frequency and the specificity of deletion formation in this gene region.

Effect of isopropyl-beta-D-thiogalactopyranosid induction of the lac operon on the specificity of spontaneous and doxorubicin-induced mutations in Escherichia coli

Previous studies of doxorubicin-induced mutations employing F' lacl/lacO as an endogenous gene target have focused on properties of large deletions with 3' endpoints residing in the lacO region of the target gene. This study considers the influence of Lac repressor binding on the distribution of these deletions. Results of the DNA sequence level analysis of spontaneous and doxorubicin-induced i-d and lacO mutations in Escherichia coli uvrB- are reported for mutants isolated under conditions where Lac repression is relieved by isopropyl-beta-D-thiogalactopyranosid (IPTG; an inducer that prevents repressor binding to lacO). The location of deletions isolated from doxorubicin-treated cultures in the presence and absence of IPTG suggests that doxorubicin preferentially focuses deletion endpoints adjacent to its binding sites in lacO and that the distribution of these deletion endpoints is not modulated by Lac repressor binding. In contrast, spontaneous deletion endpoints are preferentially clustered in the loop away from the palindromic sequences under conditions of repression. However, when the Lac repressor/lacO binding complex is dissociated by IPTG, the spontaneous 3'-deletion endpoints distribute proportionally between the putative stem and loop of the lacO palindrome. The single most striking effect of IPTG induction of the Lac operon was elimination of a "hot spot" for T:A-->C:G transitions at position +6 in lacO. This base substitution "hot spot," which accounted for 17.6% of total doxorubicin-induced mutants and 16.4% of spontaneous mutants in repressed bacterial cultures, accounted for approximately 1% of total mutations in similar experiments carried out in the presence of IPTG. A large number of mutations at the +6 position are induced only by doxorubicin in the absence of IPTG, however, suggesting that both doxorubicin-induced and spontaneous mutation at this transition "hot spot" are mediated by Lac repressor binding to lacO.

The influence of salinity on the toxicity of various classes of chemicals to aquatic biota

The objective of this study was to review all available aquatic toxicity literature regarding the effects of salinity on the toxicity of various classes of inorganic and organic chemicals. Toxicity data for studies in which toxicity was assessed at various salinities were organized by chemical classes and trophic groups. Seventy percent of the studies were conducted with either crustaceans or fish. The other 30% were with mollusks, annelids, zooplankton, bacteria, phytoplankton, or fungi. Results from 173 data entries showed that negative correlations (toxicity increasing with decreasing salinity) were reported most frequently (55%), followed by no correlations (27%) and positive correlations (18%). The toxicity of most metals such as cadmium, chromium, copper, mercury, nickel, and zinc was reported to increase with decreasing salinity. This finding is likely related to the greater bioavailability of the free metal ion (toxic form) at lower salinity conditions. There was generally no consistent trend for the toxicity of most organic chemicals with salinity. The one exception to this was reported with organophosphate insecticides, the toxicity of which appeared to increase with increasing salinity. Physiological characteristics of the various test species were important in determining the toxicity of the various classes of chemicals at a range of salinities. Results from various studies showed that euryhaline species were more resistant to toxic conditions at isosmotic salinities due to minimization of osmotic stress. Specific examples showed that fish were more resistant to toxic chemicals at middle salinities when compared with either lower or higher extremes. Life history and ecology of test species were important factors to consider when interpreting salinity/contaminant interaction data.

Accelerated intravenous dosing of recombinant tissue-type plasminogen activator causes rapid but unstable reperfusion in a canine model of acute myocardial infarction

BACKGROUND

Accelerated intravenous dosing is currently the preferred regimen for administering recombinant tissue-type plasminogen activator (rt-PA) in acute myocardial infarction (AMI). This regimen is recommended on the basis of clinical angiographic studies that reported superior 60 and 90 min patency rates. However, continuous infarct-vessel flow characteristics after reperfusion following this regimen are poorly described. The aim of our study was an improved definition of the characteristics of infarct-vessel flow induced by intravenous accelerated rt-PA using an animal model of acute coronary artery thrombosis.

METHODS

We studied the characteristics of reperfusion induced by an accelerated intravenous rt-PA dosing regimen in a canine coronary artery thrombosis model that simulates AMI. We created a critical stenosis in the left anterior descending coronary artery (LAD) of 24 open-chest dogs. Thrombosis was caused immediately proximal to the stenosis by injection of a blood and thrombin mixture into a segment of the LAD which had intimal damage. Hemodynamics and distal LAD blood flow velocity were recorded continuously. Six animals did not complete the protocol. Animals in the treatment group (n = 10) received an intravenous accelerated rt-PA regimen (1.25 mg/kg total dose) and were observed for 150 min. Eight animals served as controls.

RESULTS

None of the control animal arteries reperfused. In the treatment group, reperfusion occurred 31.5 +/- 7.3 min after starting rt-PA dosing in two general patterns. In one pattern, reperfusion onset was gradual and linear; in the other pattern, reperfusion was sudden. LAD flow was cyclical in all animals, with marked variations in magnitude compared with baseline (0-173% of baseline). Reocclusion was common and occurred 30.3 +/- 6.3 min after the initial reperfusion. There were 1.9 +/- 0.4 reocclusions per animal, and two distinct patterns were noted. In one, flow ceased abruptly and, in the second, flow declined gradually in a linear fashion before stopping. Infarct-vessel flow was evident for 103.1 +/- 14.1 min of the 150 min observation period.

CONCLUSIONS

Reperfusion occurs rapidly after an accelerated dosing regimen of rt-PA. However, the infarct-vessel flow resulting from this therapy is unstable and is associated with early reocclusion and marked variation in flow magnitude. Analysis of continuous infarct-vessel flow velocity patterns suggests at least two different mechanisms for the onset of reperfusion and reocclusion after this therapy. Recognizing several mechanisms of arterial opening and closing may have important implications for methods of stabilizing infarct vessels after reperfusion by accelerated dosing of rt-PA.

Missense mutations in the adhalin gene linked to autosomal recessive muscular dystrophy

Adhalin, the 50 kDa dystrophin-associated glycoprotein, is deficient in skeletal muscle of patients having severe childhood autosomal recessive muscular dystrophy (SCARMD). In several North African families, SCARMD has been linked to chromosome 13q, but SCARMD has been excluded from linkage to this locus in other families. We have now cloned human adhalin cDNA and mapped the adhalin gene to chromosome 17q12-q21.33, excluding it from involvement in 13q-linked SCARMD. However, one allelic variant of a polymorphic microsatellite located within intron 6 of the adhalin gene cosegregated perfectly with the disease phenotype in a large family. Furthermore, missense mutations were identified within the adhalin gene that might cause SCARMD in this family. Thus, the adhalin gene is involved in at least one form of autosomal recessive muscular dystrophy.

Alpha-dystroglycan deficiency correlates with elevated serum creatine kinase and decreased muscle contraction tension in golden retriever muscular dystrophy

The dystrophin-glycoprotein complex was examined in dystrophin-deficient dogs with golden retriever muscular dystrophy (GRMD) using immunoblot and immunofluorescence analysis. The dystrophin-associated proteins were substantially reduced in muscle from dogs with GRMD. Interestingly, regression analysis revealed a strong correlation between the amount of alpha-dystroglycan and serum creatine kinase levels and the contraction tension measured for a given peroneus longus muscle.

International Commission for Protection Against Environmental Mutagens and Carcinogens. Mutagenicity and carcinogenicity of topoisomerase-interactive agents

Drugs that interact with DNA topoisomerases I and II hold great promise for the treatment of cancer, however, like many other anti-cancer agents, they are a double-edged sword and may themselves cause mutation and cancer. In vitro studies show that clinically effective agents, such as etoposide, doxorubicin and others, stabilize a ternary complex where topoisomerase II is covalently linked to DNA. This complex represents an intermediate in the topoisomerase-II catalyzed DNA supercoil relaxation reaction. Camptothecin and its analogues stabilize a similar ternary complex, in vitro, consisting of topoisomerase I covalently linked to DNA at single-strand breaks. Short-term tests of genotoxicity confirm that topoisomerase-interactive agents are mutagenic and suggest common mechanisms by which they induce mutation and selectively kill tumor cells. These agents induce sister-chromatid exchange, chromosomal aberrations and mutations in specific mammalian genes. Their propensity to induce small colonies in the L5178/TK+/(-)-3.7.2C assay implies that topoisomerase-interactive agents induce large DNA rearrangements and deletions. These may result from topoisomerase-subunit exchange at drug-stabilized ternary complexes or from attempts by the cell to bypass the replication block caused by stabilized ternary complexes. Studies in bacterial mutation assays suggest that topoisomerase-interactive agents may also induce mutations, albeit at a lower rate, through simple DNA intercalation or via generation of oxygen free radicals. Second malignancies observed in patients previously treated with topoisomerase II interactive agents suggest these may be an important clinical consequence of their capacity to induce mutation. In particular, a unique form of acute myelogenous leukemia is observed at strikingly high frequencies after treatment with relatively high doses of the epipodophyllotoxins etoposide and teniposide. This form of AML has been reported after the uses of other classes of topoisomerase-interactive agents as well. Cancer induction is therefore a toxic consequence predicted by short-term tests of genotoxicity and should be weighed against the potential therapeutic benefits of topoisomerase-interactive agents.

The efficacy of a limestone doser to mitigate stream acidification in a Maryland coastal plain stream: Implications for migratory fish species

The objective of this two-year study was to determine the efficacy of an automated limestone slurry doser to neutralize acidic pulses and improve water quality conditions for enhancing survival of early life stages of migratory fish species in a Maryland coastal plain stream. Implications for survival of early life stages of migratory fish species such as yellow perch (Perca flavescens), white perch (Morone americana), blueback herring (Alosa aestivalis) and alewife (Alosa pseudoharengus) are discussed based on the improved chemical conditions in the dosed area of the stream. Despite problems with overdosing in 1991 and failure of the stage transducer to work properly in 1992, the doser was generally effective in neutralizing acidic pulses (pH depressions) in the stream during three major rain events in both years. Chemical conditions (pH and inorganic monomeric aluminum) reported in the non-dosed area during major rainfall events were potentially stressful to both alewife and blueback herring although neither species was reported spawning in the stream during either year. Mitigating the potential impact of acidic conditions on early life stages of important migratory fish species was not sufficient to ensure spawning. It is therefore recommended that habitat improvement measures and well designed fish stocking programs be implemented concurrently with doser operations if the goal is to create optimum spawning conditions for migratory species.

Genetic heterogeneity of severe childhood autosomal recessive muscular dystrophy with adhalin (50 kDa dystrophin-associated glycoprotein) deficiency

Severe autosomal recessive muscular dystrophy (SCARMD), McKusick n. 253700, has been originally described in North-African populations, in which significant linkage has been established with DNA markers mapping to the proximal region of the long arm of chromosome 13, without evidence for heterogeneity of the SCARMD locus in these populations. A striking feature of this disease is the isolated deficiency of adhalin, a sarcolemmal 50 kDa dystrophin-associated glycoprotein. We report a non-inbred French family with a milder progressive form of muscular dystrophy affecting subjects of both sexes. The parents are not affected suggesting an autosomal recessive transmission. In 4 siblings displaying mild to overt clinical signs of muscular dystrophy, serum creatine kinase was high, and muscle specimens showed variable degree of necrosis-regeneration with little fibrosis. In the 4 cases adhalin was completely absent in muscle sections, whereas dystrophin and the other members of the dystrophin-associated protein complex were normal, except for the 35 kDa dystrophin-associated glycoprotein which was decreased as usually observed in SCARMD. Linkage and homogeneity analysis using 4 microsatellite markers of chromosome 13q that are linked to the North-African SCARMD locus were performed in this family. Results show that the morbid locus involved in this family does not map to the same region as the SCARMD locus. This second locus may be involved in sporadic cases of muscular dystrophy with adhalin deficiency that have been reported in Europe.

A canine model of acute coronary artery thrombosis for the evaluation of reperfusion strategies

A model of coronary artery thrombosis which: (1) provides a stable thrombus; (2) incorporates intimal injury; (3) has a low mortality rate; (4) responds predictably to thrombolytic therapy, and (5) is technically simple, was developed. Intimal injury was produced proximal to a critical stenosis and followed by the infusion of a blood and thrombin mixture into the injured segment. After thrombus formation flow remained absent in all control animals (n = 7). Microscopy showed intimal injury and coronary thrombosis with platelets adherent to the subendothelium. In animals treated with tissue plasminogen activator (n = 7) flow returned to > 60% of baseline at 20.2 +/- 7.7 min and was cyclical. Mortality and complications were infrequent. This model is useful in investigations of reperfusion therapy.

Arterial diastolic pressure augmentation by intra-aortic balloon counterpulsation enhances the onset of coronary artery reperfusion by thrombolytic therapy

BACKGROUND

The early establishment of infarct artery reperfusion by intravenous thrombolytic therapy has improved survival after acute myocardial infarction. Investigations of reperfusion have focused on the effects of specific thrombolytic agents, anticoagulation, and platelet inhibition. However, little attention has been given to the relation of arterial blood pressure to thrombolysis, a factor that probably affects thrombolytic agent delivery to the obstructing thrombus.

METHODS AND RESULTS

The effect of arterial diastolic pressure augmentation by intra-aortic balloon counterpulsation (IABP) on reperfusion after intravenous thrombolytic therapy was studied in a canine model. A critical left anterior descending coronary artery stenosis was created by an occluder. Acute thrombosis immediately proximal to the occluder was formed by local injection of a blood and thrombin mixture into a segment of the artery that had intimal damage (groups 1 through 3). Continuous coronary blood flow velocity was measured by an epicardial Doppler probe. Group 1 (n = 7) served as control. Group 2 (n = 6) received an intravenous, front-loaded recombinant tissue-type plasminogen activator (rTPA) regimen (1.25 mg/kg total dose, 15% as bolus, 50% in the first 30 minutes, and 35% for the following 60 minutes). Group 3 (n = 6) received the same rTPA regimen with IABP beginning at the start of rTPA administration. Coronary blood flow velocity, arterial pressure, and heart rate were observed for 150 minutes after the start of thrombolytic therapy. Five animals did not undergo coronary thrombosis (group 4) and had coronary blood flow velocity determined before and after IABP at baseline and after creation of critical stenosis. Mean systolic arterial blood pressure and heart rate were not statistically different between groups. Peak augmented diastolic pressure by IABP was 97.9 +/- 1.3% of systolic pressure in group 3 dogs. Spontaneous reperfusion did not occur in any group 1 dogs. All animals treated with rTPA reperfused. Reperfusion occurred in group 3 (13.1 +/- 2.1 minutes) earlier than in group 2 (39.2 +/- 9.4 minutes, P = .02). Overall duration of arterial patency did not differ between group 2 (81.4 +/- 16.6 minutes) and group 3 (94.9 +/- 15.3 minutes, P = .52). Reocclusions occurred with similar frequency (P = .85) in groups 2 and 3. In group 4, IABP did not increase baseline coronary blood flow velocity.

CONCLUSIONS

This study demonstrates that augmentation of diastolic arterial pressure by IABP enhances thrombolysis, leading to faster reperfusion. This effect appears to be unrelated to an increase in coronary blood flow and may be due to an effect of the augmented diastolic blood pressure wave on the obstructing thrombus. These findings suggest that the time to reperfusion by rTPA may be blood pressure dependent. The relation of arterial blood pressure to successful thrombolysis may have important implications for future treatment strategies for myocardial infarction.

Primary structure and muscle-specific expression of the 50-kDa dystrophin-associated glycoprotein (adhalin)

The 50-kDa dystrophin-associated glycoprotein (50-DAG) is a component of the dystrophin-glycoprotein complex, which links the muscle cytoskeleton to the extracellular matrix. 50-DAG is specifically deficient in skeletal muscle of patients with severe childhood autosomal recessive muscular dystrophy and in skeletal and cardiac muscles of BIO 14.6 cardiomyopathic hamsters. The lack of 50-DAG leads to a disruption and dysfunction of the dystrophin-glycoprotein complex in these diseases. The cDNA encoding 50-DAG has now been cloned from rabbit skeletal muscle. The 50-DAG deduced amino acid sequence predicts a novel protein having 387 amino acids, a 17-amino acid signal sequence, one transmembrane domain, and two potential sites of N-linked glycosylation. Affinity-purified antibodies against rabbit 50-DAG fusion proteins or synthetic peptides specifically recognized a 50-kDa protein in skeletal muscle sarcolemma and the 50-kDa component of the dystrophin-glycoprotein complex. In contrast to dystroglycan, which is expressed in a wide variety of muscle and non-muscle tissues, 50-DAG is expressed only in skeletal and cardiac muscles and in selected smooth muscles. Finally, 50-DAG mRNA is present in mdx and Duchenne muscular dystrophy (DMD) muscle, indicating that the down-regulation of this protein in DMD and the mdx mouse is likely a post-translational event.

Genetic heterogeneity for Duchenne-like muscular dystrophy (DLMD) based on linkage and 50 DAG analysis

Duchenne-like muscular dystrophy (DLMD) is an autosomal recessive (AR) muscular dystrophy which presents a clinical course indistinguishable from the Xp21 Duchenne muscular dystrophy or DMD. Recently, Othmane et al., based on a linkage study with 13q12 markers in 3 highly inbred DLMD families from Tunisia, suggested that the gene for this myopathy lies in the pericentromeric region of chromosome 13q. It is unknown if there is genetic heterogeneity causing the DLMD phenotype. Therefore, the aim of the present report is to describe the results of linkage analysis in 4 Brazilian DLMD families with 13q12 markers (D13S115 and D13S120), which were also tested for 50DAG. It was possible to exclude the 13q gene at theta = 0.10 as responsible for the DLMD phenotype in our families using both 13q12 markers, if the lod scores of each family were added up. Interestingly, 3 families were deficient for 50 DAG while one showed a positive pattern for this glycoprotein. Therefore, these results suggest: a) the DLMD phenotype is caused by more than one recessive gene; b) a gene, not located at 13q, causes deficiency of 50 DAG as a primary or secondary defect.

The expanded "BAT" flap for treatment of male pattern baldness

A new combination of expanded simultaneous transposition and advancement flaps is reported for the treatment of extensive male pattern baldness. Although vertical transposition and parieto-occipital advancement flaps in themselves are not new, their combination and simultaneous bilateral use combined with the use of expansion is new. The advantages of the expanded bilateral advancement transposition flap procedure are presented, along with the technique and results. The results are predictable, providing a more pleasing result, with a natural immediate temporal recession, avoidance of temporal dog-ears, and desirable anterior-superior direction of hair growth. Although flaps do require surgical skill and training, and there are risks and possible complications involved, the results are achieved in a relatively short time compared with grafting techniques. Flaps also provide the advantages of a full and natural hairline contrasted with the sparse look afforded by multiple grafts. The described procedures are very effective and reliable when properly planned and properly executed.

Excision repair reduces doxorubicin-induced genotoxicity

LacI mutations induced by doxorubicin in a wild-type, uvr(A)BC repair-proficient E. coli strain were analyzed by DNA sequencing. These mutations were contrasted with mutations previously recovered from doxorubicin-treated uvrB- organisms in order to assess the role of excision repair in doxorubicin-induced genotoxicity. After a 30-min exposure of wild-type E. coli to 330 microM doxorubicin, survival was 34% and the overall lacI mutation frequency increased 1.8-fold to 340 x 10(-8). The distribution of doxorubicin-induced mutants among subclasses of mutation involving the i-d and lac operator regions differed significantly between repair-proficient and -deficient strains. Distributional differences appeared to result both from a decrease in deletions involving the lac operator and an increase in base substitutions involving the i-d region in repair proficient organisms. However, elements of the doxorubicin-induced mutation spectrum in uvrB- E. coli are still discernable in wild-type organisms. These elements include the remarkable shift of 3'-deletion endpoints to palindromic sequence within the lac operator and the recovery of multiple isolates of T:A-->A:T transversions at position 96 in doxorubicin-treated cultures. These observations suggest that components of the uvr(A)BC nucleotide excision repair system function through a general mechanism prior to fixation of mutations to reduce, but not completely eliminate, the genotoxic effects of doxorubicin.

Deficiency of dystrophin-associated proteins in Duchenne muscular dystrophy patients lacking COOH-terminal domains of dystrophin

Dystrophin, the protein product of the Duchenne muscular dystrophy (DMD) gene, is a cytoskeletal protein tightly associated with a large oligomeric complex of sarcolemmal glycoproteins including dystroglycan, which provides a linkage to the extracellular matrix component, laminin. In DMD, the absence of dystrophin leads to a drastic reduction in all of the dystrophin-associated proteins, causing the disruption of the linkage between the subsarcolemmal cytoskeleton and the extracellular matrix which, in turn, may render muscle cells susceptible to necrosis. The COOH-terminal domains (cysteine-rich and carboxyl-terminal) of dystrophin have been suggested to interact with the sarcolemmal glycoprotein complex. However, truncated dystrophin lacking these domains was reported to be localized to the sarcolemma in four DMD patients recently. Here we report that all of the dystrophin-associated proteins are drastically reduced in the sarcolemma of three DMD patients in whom dystrophin lacking the COOH-terminal domains was properly localized to the sarcolemma. Our results indicate that the COOH-terminal domains of dystrophin are required for the proper interaction of dystrophin with the dystrophin-associated proteins and also support our hypothesis that the loss of the dystrophin-associated proteins in the sarcolemma leads to severe muscular dystrophy even when truncated dystrophin is present in the subsarcolemmal cytoskeleton.

Sequencing of double-stranded polymerase chain reaction products for mutation analysis

This report describes a reproducible, straightforward approach to sequencing double-stranded DNA products from the polymerase chain reaction (PCR) for analysis of mutations. The sequencing protocol is a modification of that published by Kretz (Kretz et al., 1989) and has been successful in the hands of a number of investigators working on diverse projects. Following this procedure, PCR DNA products generated from bacterial sources (including pBR322 and F' derivatives), as well as cDNA and genomic DNA from both hamster and human cell lines, have been sequenced with equal success. Close attention to the molar ratio of nucleotides to double-stranded DNA template present during the labeling reaction ensures best results.