Differences in Myocardial Remodeling and Tissue Characteristics in Chronic Isolated Aortic and Mitral Regurgitation

BACKGROUND

The left ventricular hemodynamic load differs between aortic regurgitation (AR) and primary mitral regurgitation (MR). We used cardiac magnetic resonance to compare left ventricular remodeling patterns, systemic forward stroke volume, and tissue characteristics between patients with isolated AR and isolated MR.

METHODS

We assessed remodeling parameters across the spectrum of regurgitant volume. Left ventricular volumes and mass were compared against normal values for age and sex. We calculated forward stroke volume (planimetered left ventricular stroke volume-regurgitant volume) and derived a cardiac magnetic resonance-based systemic cardiac index. We assessed symptom status according to remodeling patterns. We also evaluated the prevalence of myocardial scarring using late gadolinium enhancement imaging, and the extent of interstitial expansion via extracellular volume fraction.

RESULTS

We studied 664 patients (240 AR, 424 primary MR), median age of 60.7 (49.5-69.9) years. AR led to more pronounced increases in ventricular volume and mass compared with MR across the spectrum of regurgitant volume (P<0.001). In ≥moderate regurgitation, AR patients had a higher prevalence of eccentric hypertrophy (58.3% versus 17.5% in MR; P<0.001), whereas MR patients had normal geometry (56.7%) followed by myocardial thinning with low mass/volume ratio (18.4%). The patterns of eccentric hypertrophy and myocardial thinning were more common in symptomatic AR and MR patients (P<0.001). Systemic cardiac index remained unchanged across the spectrum of AR, whereas it progressively declined with increasing MR volume. Patients with MR had a higher prevalence of myocardial scarring and higher extracellular volume with increasing regurgitant volume (P value for trend <0.001), whereas they were unchanged across the spectrum of AR (P=0.24 and 0.42, respectively).

CONCLUSIONS

Cardiac magnetic resonance identified significant heterogeneity in remodeling patterns and tissue characteristics at matched degrees of AR and MR. Further research is needed to examine if these differences impact reverse remodeling and clinical outcomes after intervention.

Endocarditis Presenting as Right Atrial Mass, Diagnosed with 18F-Fluorodeoxyglucose-PET: A Case Report

We report a case of a 55-year-old male with a history of methicillin-resistant staphylococcus aureus bacteremia whose initial transesophageal echocardiography revealed a cardiac mass attached to the right atrium. Because of the uncommon location of the mass, 18F-fluorodeoxyglucose-PET was used to confirm the diagnosis of infective endocarditis.

AB0209 PHYSICIAN TRUST RATHER THAN RHEUMATOID ARTHRITIS KNOWLEDGE RELEVANT IN DISEASE OUTCOMES IN ETHNIC MINORITY PATIENTS WITH RHEUMATOID ARTHRITIS

Background

Ethnic minority (EM) patients with Rheumatoid Arthritis (RA) have more severe disease, more disability, and less use of biologic disease modifying anti-rheumatic drugs (bDMARDs). A Treat to target (T2T) strategy has been recommended to improve clinical outcomes but barriers include patient preference, access to specialty care and increased administrative effort. Additionally, EM patients in the US often have low health literacy, express greater reluctance to accept physician recommendations, in part due to sociocultural preference and mistrust of a historically biased healthcare system. It is unknown whether improving knowledge of RA would improve T2T outcomes in EM active RA patients.

Objectives

To assess the proportion of EM RA patients who achieve low disease activity or remission following implementation of a coordinator-based education program highlighting T2T RA strategy.

Methods

Adult participants with active RA (RAPID3>6 or CDAI > 10) were invited to participate in a series of five one-on-one 20-minute educational sessions, co-occurring with scheduled routine clinic visits (6 -12-week intervals). Sessions were facilitated by a rheumatology care coordinator, a non-healthcare professional with intensive training over 4 weeks to conduct RA patient education. Sociodemographic data was collected, and disease activity measures (TJC, SJC, RAPID3, CDAI) and validated patient questionnaires on RA Knowledge (ACREU), compliance (CQR5), and physician trust (Trust in Physician Scale) were recorded at baseline and after the final educational session. Descriptive statistics were applied and medians and ranges for instrument scores are reported. Paired T-test was used to test for significant differences in scores after the education sessions. Correlations between the ACREU scores and clinical-demographic variables were measured using Pearson’s correlation coefficient.

Results

20 EM patients (75% Female, mean age, 58.8 years (12.2) seen by EM physicians were enrolled, with mean RA disease duration of 7 years and poor prognosticators (75% double seropositivity). ACREU scores were low at baseline (mean 0.45 (0.16)), with no significant improvement on completion of educational sessions, and no correlation with years of education or duration of RA. There was a positive correlation between ACREU and compliance scores at baseline (r=0.3). Average duration of the education period was 9.72 months, with a 33% decrease in average RAPID3 over time, and 42% of patients achieving a target of remission or LDA. Trust in Physician scores were high at baseline and persisted with >50% of patients completing at least one medication change during study period.

Conclusion

RA knowledge did not impact RA patient outcomes in this cohort of EM patients. However, patients had high trust in their providers and achieved clinical remission or LDA despite risk for poor outcomes highlighting the importance of the provider- patient relationship in achieving targeted goals of therapy. Limitations include the small sample size from a single institution, and the lengthy time between initial and final assessment of RA knowledge.

References

[1]Lineker SC, Badley EM, Hughes EA, Bell MJ. Development of an instrument to measure knowledge in individuals with rheumatoid arthritis: the ACREU rheumatoid arthritis knowledge questionnaire. The Journal of rheumatology. 1997/04// 1997;24(4):647-653.

[2]Hughes LD, Done J, Young A. A 5 item version of the Compliance Questionnaire for Rheumatology (CQR5) successfully identifies low adherence to DMARDs. BMC Musculoskeletal Disorders. 2013-12-01 2013;14(1):286. doi:10.1186/1471-2474-14-286

[3]Anderson LA, Dedrick RF. Development of the Trust in Physician Scale: A Measure to Assess Interpersonal Trust in Patient-Physician Relationships. Psychological Reports. 1990-12-01 1990;67(3_suppl):1091-1100. doi:10.2466/pr0.1990.67.3f.1091

Acknowledgements

Sincere gratitude to our patients for their participation, and to the team at Bristol Myers Squibb for supporting this research initiative.

Disclosure of Interests

Sharon Dowell Speakers bureau: Horizon Pharma, Aurinia Pharmaceuticals Inc, Abbvie, Grant/research support from: Pfizer, Bristol Myers Squibb, Mercedes Quinones Speakers bureau: Abbvie, Sanofi Genzyme, Grant/research support from: Bristol Myers Squibb, Pfizer, Alani Miller: None declared, Oshoze Kadiri: None declared, Tahereh Jamshidi: None declared, Gail Kerr Speakers bureau: Aurinia Pharmaceuticals Inc, Consultant of: CSL Behring, Janssen, Pfizer, Samumed, UCB, Viela Bio/Horizon, Grant/research support from: Novartis

Myocardial Scar and Mortality in Chronic Aortic Regurgitation

Background

Chronic aortic regurgitation (AR) can be associated with myocardial scarring. It is unknown if scarring in AR is linked to poor outcomes and whether aortic valve replacement impacts this association. We investigated the relationship of myocardial scarring to mortality in chronic AR using cardiac magnetic resonance.

Methods and Results

We enrolled patients with moderate or greater AR between 2009 and 2019 and performed a blinded assessment of left ventricle remodeling, AR severity, and presence and extent of myocardial scarring by late gadolinium enhancement. The primary outcome was all‐cause mortality. We followed 392 patients (median age 62 [interquartile range, 51–71] years), and 78.1% were men, and 25.8% had bicuspid valves. Median aortic valve regurgitant volume was 39 mL (interquartile range, 30–60). Myocardial scar was present in 131 (33.4%) patients. Aortic valve replacement was performed in 165 (49.1%) patients. During follow‐up, up to 10.8 years (median 32.3 months [interquartile range, 9.8–69.5]), 51 patients (13%) died. Presence of myocardial scar (hazard ratio [HR], 3.62; 95% CI, 2.06–6.36; P<0.001), infarction scar (HR, 4.94; 95% CI, 2.58–9.48; P<0.001), and noninfarction scar (HR, 2.75; 95% CI, 1.39–5.44; P<0.004) were associated with mortality. In multivariable analysis, the presence of scar remained independently associated with death (HR, 2.53; 95% CI, 1.15–5.57; P=0.02). Among patients with myocardial scar, aortic valve replacement was independently associated with a lower risk of mortality (HR, 0.34; 95% CI, 0.12–0.97; P=0.03), even after adjustment for confounders.

Conclusions

In aortic regurgitation, myocardial scar is independently associated with a 2.5‐fold increase risk in mortality. Aortic valve replacement was associated with a reduction in risk of mortality in patients with scarring.

Consensus guidelines from The American Society of Peritoneal Surface Malignancies on standardizing the delivery of hyperthermic intraperitoneal chemotherapy (HIPEC) in colorectal cancer patients in the United States

BACKGROUND

The American Society of Peritoneal Surface Malignancies (ASPSM) is a consortium of cancer centers performing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC). This is a position paper from the ASPSM on the standardization of the delivery of HIPEC.

METHODS

A survey was conducted of all cancer centers performing HIPEC in the United States. We attempted to obtain consensus by the modified method of Delphi on seven key HIPEC parameters: (1) method, (2) inflow temperature, (3) perfusate volume, (4) drug, (5) dosage, (6) timing of drug delivery, and (7) total perfusion time. Statistical analysis was performed using nonparametric tests.

RESULTS

Response rates for ASPSM members (n = 45) and non-ASPSM members (n = 24) were 89 and 33 %, respectively. Of the responders from ASPSM members, 95 % agreed with implementing the proposal. Majority of the surgical oncologists favored the closed method of delivery with a standardized dual dose of mitomycin for a 90-min chemoperfusion for patients undergoing cytoreductive surgery for peritoneal carcinomatosis of colorectal origin.

CONCLUSIONS

This recommendation on a standardized delivery of HIPEC in patients with colorectal cancer represents an important first step in enhancing research in this field. Studies directed at maximizing the efficacy of each of the seven key elements will need to follow.

Lamotrigine vs. lamotrigine plus divalproex in randomized, placebo-controlled maintenance treatment for bipolar depression

OBJECTIVE

To compare the maintenance efficacy of lamotrigine (Lam) to combination therapy of Lam+divalproex ER (Div) in recently depressed patients with bipolar disorder (BD).

METHOD

We randomized 86 BD I or II patients in a major depressive episode to 8 months of double-blind treatment with Lam+placebo or Lam+Div. To be eligible for randomization, patients had to achieve control of both depressive and manic symptoms during an open phase that included both Lam and Div.

RESULTS

Time to depressive episode did not differ significantly by Kaplan-Maier survival analysis (χ2=1.82, df=1, P=0.18). However, several secondary outcomes did show significant differences. The proportion of Lam+placebo patients who had at least one Montgomery-Asberg Depression Rating Scale (MADRS) score≥15 during the maintenance phase was 67% (30/45) compared with 44% (18/41) for the Lam+Div group (χ2=4.51, P=0.03). Among BD I patients assigned to Lam+placebo, 71.4% (25/35) had at least one visit with MADRS score≥15 compared with 36.7% (11/30) among Lam+Div patients (χ2=7.89, df=1, P=0.005).

CONCLUSION

Lam+Div generally provided greater maintenance efficacy than Lam alone for depressive indices in recently depressed BD patients.

Development of a Multiple-Lumen Nerve Cuff Utilizing Growth Stimulant Patterns for Controlled Regeneration

Silicone rubber multiple-lumen (ML) nerve cuffs were used for side-by-side comparisons of the effectiveness of two varieties of nerve growth stimulants (collagen gel and a gel mixture of collagen, fibronectin, and laminin) for regenerating cables across a 15 mm gap in 10 adult Sprague-Dawley rats. The filling pattern of the six tubes of the multiple-lumen portion of the cuff alternated with the collagen gel and the gel mixture of collagen, fibronectin, and laminin. After an 8 week implantation period, 53% (32 of 60) of the 0.5 mm diameter lumens displayed successful cable regeneration for both material fillings. The ML cuff experiments demonstrate the ability to bridge a 15 mm gap in the sciatic nerve of the rat by 8 weeks for relatively small diameter conduits in ML cuffs loaded with two varieties of growth stimulants. A more advanced organization including a smaller acellular region fraction and a higher vascularity is seen in the cables from the mixture-filled lumens compared to those in the cables from the collagen-filled lumens.

Phase I study of oral S-1 in combination with oxaliplatin (oxali) and bevacizumab (bev) in patients with advanced solid tumors

4091

Background: S-1 is a novel oral fluoropyrimidine (tegafur, CDHP and potassium oxonate) designed for enhanced DPD inhibition and reduced GI toxicity. Bev and oxali have demonstrated safety and synergistic anti-tumor activity with oral and IV fluoropyrimidines. The primary objective is to investigate the safety and maximum tolerated dose (MTD) of S-1 combined with bevacizumab and oxaliplatin in patients with advanced solid tumors. Secondary objective is to investigate the clinical pharmacokinetics (PK) of the components of S-1 (FT, CDHP, Oxo), 5-FU, a-fluoro-β-alanine, cyanuric acid, uracil, and oxali and to document any antitumor activity. Methods: ECOG 0/1 patients with advanced or metastatic solid tumors received oral S-1 starting at 20 mg/m2/dose BID x 14 days (classic 3+3 cohort dose escalation by 5mg/m2/dose until MTD), plus fixed doses of bev 7.5 mg/kg IV day 1, and Oxali 130 mg/m2 IV day 1 of every 3 week cycle, with discontinuation of oxali after 4 cycles. Reintroduction of oxali was allowed upon progression of disease. Toxicity, antitumor activity and PKs were assessed. The MTD was defined as the highest dose level at which < 33% of the patients experience a dose- limiting toxicity (DLT) during the first 2 cycles. Results: Of 22 evaluable patients, 3 patients were treated at 20mg/m2 S1 and 13 patients were treated at 25mg/m2 S1 without a DLT. At 30mg/m2, two patients experienced a DLT(Grade 3 diarrhea, Grade 4 mucositis). The MTD and recommended phase II dose of S-1 is 25mg/m2 in combination with oxali and bev. A median of 8 cycles of S-1 were initiated at the 25 mg/m2 dose level. Common MTD level toxicities included fatigue (62%), nausea (62%) and diarrhea (46%), with no grade 4 toxicities observed. Best responses (RECIST): stable disease(16 patients), partial response (2 patients), non-measurable disease (3 patients). The Day 8 AUC(0–8) of 5-FU at 20/25/30 mg/m2 dose level were 230±115 hr*ng/ml, 470±172 hr*ng/ml and 502±169 hr*ng/ml, respectively. Conclusions: The MTD combination of 25mg/m2 S-1, oxali and bev can be given safely. The study will be expanded to test S-1 one week on, one week off schedule in combination with oxali/bev every two weeks.

No significant financial relationships to disclose.

Effects of Selective Matrix Metalloproteinase Inhibitor (PG-116800) to Prevent Ventricular Remodeling After Myocardial Infarction

OBJECTIVES

We sought to determine whether matrix metalloproteinase (MMP) inhibitor, PG-116800, reduced left ventricular (LV) remodeling after myocardial infarction (MI).

BACKGROUND

PG-116800 is an oral MMP inhibitor with significant antiremodeling effects in animal models of MI and ischemic heart failure.

METHODS

In an international, randomized, double-blind, placebo-controlled study, 253 patients with first ST-segment elevation MI and ejection fraction between 15% and 40% were enrolled 48+/- 24 h after MI and treated with placebo or PG-116800 for 90 days. Major efficacy end points were changes in LV volumes as determined by serial echocardiography, and clinical and safety outcomes were also collected.

RESULTS

In total, 203 patients (80%) completed 90 days of treatment and had evaluable baseline and 90-day echocardiograms. The proportion of patients with anterior MI (78% vs. 81%) and primary percutaneous coronary intervention (90% vs. 91%) along with baseline LV ejection fraction (35.5% vs. 36.8%) did not differ between PG-116800-treated and placebo-treated patients. There was no difference in the change in LV end-diastolic volume index from days 0 to 90 with PG-116800 versus placebo (5.09 +/- 1.45 ml/m(2) vs. 5.48 +/- 1.41 ml/m2, p = 0.42). Changes in LV diastolic volume, LV systolic volume, LV ejection fraction, sphericity index, plus rates of death or reinfarction were not significantly improved with PG-116800. PG-116800 was well tolerated; however, there was increased incidence of arthralgia and joint stiffness without significant increase in overall musculoskeletal adverse events (21% vs. 15%, p = 0.33).

CONCLUSIONS

Matrix metalloproteinase inhibition with PG-116800 failed to reduce LV remodeling or improve clinical outcomes after MI.

Phase I trial of preoperative cetuximab with concurrent continuous infusion 5-fluorouracil and pelvic radiation in patients with local-regionally advanced rectal cancer

3560

Background: Cetuximab, a chimeric anti-EGFR monoclonal antibody, has clinical activity in colorectal cancer with demonstrated safety, efficacy and additive synergy with radiation in solid tumors (head & neck, lung). A pilot trial was therefore designed to investigate the safety of cetuximab in combination with standard neoadjuvant protracted infusion 5-FU and radiation therapy in ultrasound T3–4 (uT3–4) or clinical T4 (cT4) or locally recurrent rectal adenocarcinoma. Secondary objectives of clinical activity were assessed by R0 resection and pathologic complete response (CR) rates. Methods: uT3–4 or cT4 or locally recurrent rectal adenocarcinoma patients received cetuximab 400mg/m2 day 1 (250mg/m2 weekly thereafter) and 5-FU IVCI (225mg/m2) over 5.5 weeks with concurrent pelvic radiation (5040cGy), and cetuximab (250mg/m2 Qweek) for 4 additional weeks, followed by surgical resection 1–3 weeks later. Results: Total Treated: 20 patients (ages 27 - 72), 19 uT3 patients, 1 Local Recurrence patient. Cetuximab Therapy (10 planned treatments): Too early 2 pts, ≥ 8 doses 12 pts, 5 - 8 doses 2 pts, < 5 total doses 4pts* (*cetuximab not given due to: 1 pt - acute cholecystitis from cholelithiasis; 1 pt - Grade 3 radiation perineal toxicity; 2 pts - treatment non-compliance). Radiation Therapy - 18 pts completed, 2 pts too early. Grade 3/4 Toxicities: Diarrhea 10%, Acneiform Rash (outside RT field) 15%, Stomatitis 5%, Radiation Field Dermatitis 5%, Transaminitis 5%. Surgical Outcomes: (17 pts completed surgery): R0 Resection 100%, Pathologic CR 12%. Conclusions: Cetuximab in combination with protracted infusion 5-FU and concurrent radiation is feasible without synergistic or unexpected toxicities. Further randomized investigation of this regimen in the neoadjuvant setting for rectal cancer is warranted.

No significant financial relationships to disclose.

Blood Pressure and Insulin Resistance Cosegregate at Two Distinct Regions on Chromosome 7

P137

Purpose: Insulin resistance (IR) and hyperinsulinemia precede hypertension in Mexican Americans and may be a preclinical phenotype for hypertension. We tested the hypothesis that IR and blood pressure (BP) share genetic regulation by conducting a genome scan in healthy adult offspring of hypertensive probands, chosen so that the traits would not have been influenced by either the disease process or treatment. Methods: A total of 390 Mexican-Americans in 77 nuclear hypertension families were genotyped with 386 microsatellite markers. We performed two-point (by SIBPAL) and multipoint linkage analysis (by SOLAR) for BP, IR, and related traits. Results: In direct support of our hypothesis, we observed evidence for two loci on chromosome 7 that influenced both IR and BP. Two-point analysis showed evidence for linkage of a locus on 7p (∼18cM) with diastolic BP (DBP), systolic BP (SBP), mean arterial pressure (MAP), and two-hour insulin (p=0.01-0.05), with a LOD of 1.44 for SBP. More impressively, the locus on 7q (∼133cM) showed lod scores of 1.78 for SBP, and 2.97 for fasting insulin. Additional quantitative traits mapping to the 7q locus are plasma levels for leptin (LOD=1.5) and apoAII (LOD=2.0). This region overlaps with the diabesity locus reported in the Pima (Hanson et al. 1998). Two candidate genes exist in the region: PPP1R3 (∼135cM), which regulates skeletal muscle glycogenesis and has a role in type 2 diabetes (Xia et al. 1998), and leptin (∼126cM). Of particular interest, it appears that the two loci interact. Thus, the 7p locus lod score for MAP increases from 0.90 to 2.37 when an interaction with 7q is introduced Conclusions: 1) The coincident mapping of loci for BP and insulin supports the role of IR in the pathogenesis of hypertension in this population. 2) There appear to be at least two different genes on chromosome 7 responsible for BP and IR. 3) There is an interaction of these two genes, suggesting they are part of a common pathway for the IR-BP syndrome.

A transgenic rabbit model for human hypertrophic cardiomyopathy

Certain mutations in genes for sarcomeric proteins cause hypertrophic cardiomyopathy (HCM). We have developed a transgenic rabbit model for HCM caused by a common point mutation in the beta-myosin heavy chain (MyHC) gene, R400Q. Wild-type and mutant human beta-MyHC cDNAs were cloned 3' to a 7-kb murine beta-MyHC promoter. We injected purified transgenes into fertilized zygotes to generate two lines each of the wild-type and mutant transgenic rabbits. Expression of transgene mRNA and protein were confirmed by Northern blotting and 2-dimensional gel electrophoresis followed by immunoblotting, respectively. Animals carrying the mutant transgene showed substantial myocyte disarray and a 3-fold increase in interstitial collagen expression in their myocardia. Mean septal thicknesses were comparable between rabbits carrying the wild type transgene and their nontransgenic littermates (NLMs) but were significantly increased in the mutant transgenic animals. Posterior wall thickness and left ventricular mass were also increased, but dimensions and systolic function were normal. Premature death was more common in mutant than in wild-type transgenic rabbits or in NLMs. Thus, cardiac expression of beta-MyHC-Q(403) in transgenic rabbits induced hypertrophy, myocyte and myofibrillar disarray, interstitial fibrosis, and premature death, phenotypes observed in humans patients with HCM due to beta-MyHC-Q(403).

Role of candidate modifier genes on the phenotypic expression of hypertrophy in patients with hypertrophic cardiomyopathy

BACKGROUND

The phenotypic expression of left ventricular hypertrophy (LVH) in patients with hypertrophic cardiomyopathy (HCM) is variable. This phenotypic variability is not completely explained by the responsible mutations or other known factors. Recent data denote a role for the modifier genes and environmental factors. We studied the role of 3 potential modifier genes, i.e., angiotensinogen (AGT), angiotensin II receptor 1a (AT1a), and endothelin-1 (END1) on the phenotypic expression of LVH in patients with hypertrophic cardiomyopathy (HCM).

METHODS

The study population was comprised of 108 genetically independent patients with HCM. Left ventricular mass index (LVMI) and LVH score were determined per published protocols. The genotypes of AGT (M235T, T174M, and G-6A), AT1a, and END1 were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) or mutation-specific PCR (MS-PCR).

RESULTS

Male patients had higher mean LVMI and LVH score than female patients (146.0 +/- 33.5 vs 129.4 +/- 33.6, p = 0.01 and 6.0 vs 5.0, p = 0.010, respectively). Gender accounted for 4.8% and 5.4% of the variability of LVMI and LVH score, respectively. The END1 genotypes also had a significant influence on LVH scores accounting for 2.9% of their variability (p = 0.042). The median LVH score was greater in patients with the AA and AG genotypes, as compared to patients with the GG genotype (7.0 vs 5.0, p = 0.034). Neither the AGT nor the AT1 genotypes had a significant influence on the expression of LVH. In multivariate regression analysis, END1 and gender accounted for 7.3% of the variability of the LVH score (p = 0.007).

CONCLUSIONS

Our results show that gender and the END1 gene modify the phenotypic expression of hypertrophy in patients with HCM.

Psychological distress, drug and alcohol use as correlates of condom use in HIV-serodiscordant heterosexual couples

OBJECTIVE

To investigate the relationship between psychological distress, alcohol, drug and condom use in HIV-serodiscordant heterosexual couples.

METHODS

Structured interviews were conducted to collect demographic information, detailed data on psychological distress, drug and alcohol use and sexual behavior.

RESULTS

Analyses were based on 106 pairs of sexually active discordant couples. Significant differences among heterosexual condom users and non-users varied according to gender and HIV serostatus. Affect domains of interpersonal sensitivity and hostility were significant, as were the variables of regular drug or alcohol use and combining sex with drugs or alcohol. Employment was strongly associated with condom use in HIV-negative women whose regular sexual partners were HIV-positive men.

CONCLUSION

The risk of vaginal sex without condoms in HIV-serodiscordant heterosexual couples may be reduced by specific psychological counseling and attention to drug and alcohol use as risk factors. Further research on the effect of employment of HIV-negative women is required.

The 44P subunit of the T4 DNA polymerase accessory protein complex catalyzes ATP hydrolysis

The genes encoding all three T4 DNA polymerase accessory proteins have been cloned into overexpression plasmids. Induction of cells harboring these plasmids results in the synthesis of each accessory protein at levels that approach 10% of the total cellular protein. The solubility of the accessory proteins after induction at 42 degrees C ranges from about 60% to greater than 95%. A plasmid that allows overexpression of the 44P/62P complex has been manipulated further to overexpress selectively the 44P subunit without 62P, permitting us to assess how each subunit contributes to the properties of the 44P/62P complex. A comparison of 44P and 44P/62P by conventional hydrodynamic techniques shows that 44P forms a subcomplex nearly as large as the 44P/62P complex. In addition, 44P catalyzes DNA-dependent ATP hydrolysis with a specific activity similar to that of the 44P/62P ATPase. However, unlike the 44P/62P complex, the ATPase activity of 44P alone is only slightly stimulated by 45P. This suggests that one role of the 62P subunit is to facilitate a productive interaction of 44P and 45P.

Skeletal muscle pseudohypertrophy in primary amyloidosis

Macroglossia and skeletal muscle enlargement with weakness appeared in a 38-year-old male who was shown to have amyloidosis and light chain multiple myeloma. Free lambda light chains were present in serum and urine. Skeletal muscle contained large amounts of amyloid and other amorphous material infiltrating blood vessel walls and connective tissue. Muscle fibers, particularly the type II variety, were diminished in size. Amyloid and similar amorphous material also were present in skin. This patient represents an unusual, but somewhat uniform, type of involvement of the neuromuscular apparatus in nonfamilial primary amyloidosis.

An evaluation of detoxification as an initial step in the treatment of heroin addiction

Of 802 voluntary patients admitted to the detoxification unit of a comprehensive treatment system, 69% completed detoxification but only 9.6% of thest patients sought long-term treatment. The demographic profile of detoxification patients differed somewhat from that of patients in long-term treatment. The authors suggest that new approaches, including legal pressure, are needed to induce detoxification patients to accept prolonged therapy.