Evaluación de competencias quirúrgicas de los egresados del programa de formación en otorrinolaringología de la Universidad de Chile / Surgical skills evaluation of the graduates from the training program in otorhinolaryngology of the University of Chile

RESUMEN Introducción En Chile, la especialidad de otorrinolaringología (ORL) es impartida por 4 universidades. La acreditación de los programas de formación de especialistas está a cargo de la Agencia Acreditadora de Programas de Posgrado de Especialidades en Medicina y Centros Formadores de Médicos Especialistas (APICE). Para la especialidad de ORL se propone una lista de cirugías y un número mínimo a realizar durante sus años de formación, esta recomendación surgió del análisis de un grupo de expertos. Objetivo Evaluar número y tipos de cirugías realizadas por egresados del Programa de Formación en ORL de la Universidad de Chile y comparar estos resultados con los criterios recomendados por APICE. Material y método Se revisaron los portafolios quirúrgicos de los egresados del programa de ORL entre los años 2006-2016 entregados en la Escuela de Posgrado de la Universidad de Chile. Se registró nombre de cirugía, rol en la cirugía (cirujano o ayudante), unidad académica, año de residencia en que se realizó y año de egreso. Resultados Se revisaron 77 portafolios, de los cuales se excluyeron 11 (1 por no tener examen rendido, 1 por entregar datos mal registrados y 9 por no especificar rol en cirugía), por lo que se tabularon 66. Ninguno de los egresados cumple con las recomendaciones APICE. Conclusiones La Universidad de Chile posee el programa de formación en ORL más antiguo y que aporta la mayor cantidad de egresados anualmente, sin embargo ninguno de éstos ha cumplido totalmente las recomendaciones de la agencia acreditadora APICE durante los últimos 10 años. Existen procedimientos frecuentes en la especialidad no incluidos en las recomendaciones.

ABSTRACT Introduction In Chile there are 4 universities with postgraduate programs in Otorhinolaryngology. The national organism that regulates postgraduate education in Medicine (APICE) recommends a minimal number of surgeries to be performed during the training, these suggestions were developed by a group of experts. Aim The objective of this paper is to explore the accomplishment of these minimal number of surgeries by the graduates of the Otorhinolaryngology Program from Universidad de Chile in the last 10 years. Material and method The surgical portafolio from the students graduated between 2006 and 2016 were reviewed. The following data was registered: year of completion of the program, surgery, kind of participation (surgeon or not), and academic location. Results In the period 77 physicians completed the program, eleven of them were excluded. The total analysis of 66 portafolios revealed that none of them accomplished a 100% of the minimal requirements suggested by APICE. Conclusions None of the graduates from the Otorhinolaryngology Program from Universidad de Chile in the last 10 years has fulfilled in 100% the requirements.

Bacterial Blight on Arugula, a New Disease Caused by Pseudomonas syringae pv. Alisalensis in California.

Beginning in 1995, a leaf spot disease has occasionally developed on the leafy crucifer arugula (Eruca vesicaria subsp. sativa) that is grown in coastal California as a fresh market commodity used mostly in bagged salad mixes. Initially, symptoms consist of small (<2 mm in diameter), angular, water-soaked spots that are visible from both sides of the leaf. The spots later enlarge, remain angular in shape, and turn brown to tan. A purple margin sometimes occurs around the spots. An important diagnostic feature is that this disease closely resembles downy mildew infections that have not produced sporangia (3). A blue-green fluorescent pseudomonad was consistently isolated from both types of lesions on King's medium B. Strains were levan positive, oxidase negative, and arginine dihydrolase negative. Strains did not rot potato slices but induced a hypersensitive reaction on tobacco (Nicotiana tabacum L. cv. Turk). These data indicated that the bacteria belonged to Lelliot's LOPAT group 1 (4). This was confirmed with data from fatty acid methyl ester analysis (MIS-TSBA version 4.10; MIDI, Inc., Newark, DE), which indicated that the strains were highly similar (similarity > = 0.758) to Pseudomonas syringae. Amplification of repetitive bacterial sequence-based polymerase chain reaction (rep-PCR) was used to determine the relationship between the P. syringae strains isolated from arugula and two common crucifer pathogens, P. syringae pv. maculicola and P. syringae pv. alisalensis (1). Using the BOXA1R primer, banding patterns for the arugula strains and the P. syringae pv. alisalensis pathotype were similar, differing by only one band. In contrast, the banding patterns of the arugula strains differed significantly from those of P. syringae pv. maculicola. Additionally, the arugula isolates were sensitive to a bacteriophage originally isolated for its ability to lyse P. syringae pv. alisalensis (1). Previously, the pathogen from arugula was reported to be P. syringae pv. maculicola (2). It is the intent of this disease note to clarify this identification. We completed Koch's postulates by confirming pathogenicity on arugula (cv. Rocket Salad). The strains were grown as nutrient broth shake cultures for 48 h at 24°C, adjusted to 108 CFU/ml, and misted onto 2- to 3-week old plants. Control plants were misted with sterile nutrient broth. After 4 to 5 days in a greenhouse (24 to 26°C), large, angular leaf lesions developed on all inoculated arugula plants. Strains were reisolated from symptomatic tissue and identified as P. syringae pv. alisalensis. Control plants remained symptomless. Similar methods confirmed that the host range of the arugula isolates were identical to that of P. syringae pv. alisalensis. The arugula and P. syringae pv. alisalensis isolates caused disease on broccoli (Brassica oleracea var. botrytis cvs. Patriot and Titleist), broccoli raab (B. rapa subsp. rapa cv. Sorento), and oats (Avena sativa cv. Montezuma), while P. syringae pv. maculicola caused disease on broccoli only. Pathogenicity tests were conducted two times with identical results. This confirms that the bacterial blight that has been occurring on commercial plantings of arugula is caused by P. syringae pv. alisalensis. References: (1) N. A. Cintas et al.Plant Dis. 86:992, 2002. (2) S. T. Koike et al. Plant Dis. 80:464, 1996. (3) S. T. Koike. Plant Dis. 82:1063, 1998. (4) R. A. Lelliott, J. Appl. Bacteriol. 29:470, 1966.

First Report of Bacterial Leaf Spot of Swiss Chard Caused by Pseudomonas syringae pv. aptata in California.

From 1999 through 2003, a previously unreported disease was found on commercial Swiss chard (Beta vulgaris subsp. cicla) in the Salinas Valley, (Monterey County) California. Each year the disease occurred sporadically throughout the long growing season from April through September. Initial symptoms were water-soaked leaf spots that measured 2 to 3 mm in diameter. As disease developed, spots became circular to ellipsoid, 3 to 8 mm in diameter, and tan with distinct brown-to-black borders. Spots were visible from the adaxial and abaxial sides. Cream-colored bacterial colonies were consistently isolated from spots. Strains were fluorescent on King's medium B, levan positive, oxidase negative, and arginine dihydrolase negative. Strains did not rot potato slices but induced a hypersensitive reaction on tobacco (Nicotiana tabacum cv. Turk). The isolates, therefore, belong in LOPAT group 1 (1). Fatty acid methyl esters (FAME) analysis (MIS-TSBA version 4.10, MIDI Inc., Newark, DE) gave variable results that included Pseudomonas syringae, P. cichorii, and P. viridiflava with similarity indices ranging from 0.91 to 0.95. BOX-polymerase chain reaction (PCR) analysis gave identical banding patterns for the chard isolates and for known P. syringae pv. aptata strains, including the pathotype strain CFBP1617 (2). The bacteria were identified as P. syringae. Pathogenicity of 11 strains was tested by growing inoculum in nutrient broth shake cultures for 48 h, diluting to 10 × 6 CFU/ml, and spraying onto 5-week-old plants of Swiss chard cvs. Red, White, Silverado, and CXS2547. Untreated control plants were sprayed with sterile nutrient broth. After 7 to 10 days in a greenhouse (24 to 26°C), leaf spots similar to those observed in the field developed on all inoculated plants. Strains were reisolated from the spots and identified as P. syringae. Control plants remained symptomless. To investigate the host range of this pathogen, the same procedures were used to inoculate three strains onto other Chenopodiaceae plants: five cultivars of sugar beet (B. vulgaris), and one cultivar each of spinach (Spinacia oleracea) and Swiss chard. In addition, five chard strains and strain CFBP1617 were inoculated onto two cultivars of sunflower (Helianthus annuus), and one cultivar each of cantaloupe (Cucumis melo), sugar beet, spinach, and Swiss chard. All Swiss chard, cantaloupe, sunflower, and sugar beet plants developed leaf spots after 7 days. The pathogen was reisolated from spots and confirmed to be the same bacterium using BOX-PCR analysis. Spinach and untreated controls failed to show symptoms. All inoculation experiments were done at least twice and the results were the same. The phenotypic data, fatty acid and genetic analyses, and pathogenicity tests indicated that these strains are P. syringae pv. aptata. To our knowledge this is the first report of bacterial leaf spot of commercially grown Swiss chard in California caused by P. syringae pv. aptata. The disease was particularly damaging when it developed in Swiss chard fields planted for "baby leaf" fresh market products. Such crops are placed on 2-m wide beds, planted with high seed densities, and are sprinkler irrigated. This disease has been reported from Asia, Australia, Europe, and other U.S. states. References: (1) R. A. Lelliott et al. J. Appl. Bacteriol. 29:470, 1966. (2) J. L. W. Rademaker et al. Mol. Microbiol. Ecol. Man. 3.4.3:1-27, 1998.

Herbal medicines today and the roots of modern pharmacology.

The transformation of digitalis from a folk medicine, foxglove, to a modern drug, digoxin, illustrates principles of modern pharmacology that have helped make drugs safer and more effective. Digitalis was improved because its preparation was standardized, first by bioassay and then by chemical methods; however, few of today's herbs are standardized by methods that can ensure a consistent product and, hence, consistent safety and efficacy profiles. Many herbs have been evaluated in randomized, controlled trials, and several-St. John's wort and ginkgo, for example-are apparently effective. Yet, many trials of herbs have limited value because of poor design, small samples, and, above all, use of products of uncertain composition and consistency. The uncertain composition of many herbal products raises questions about their safety, as does evidence indicating that herbs may have harmful interactions with prescription drugs. Such adverse effects of herbs are probably underreported. Meanwhile, systematic studies, such as those identifying adverse reactions to drugs, are hindered because herbal preparations are not standardized-one brand of St. John's wort, for example, will differ chemically from another-and, unlike for prescription drugs, there are no databases linking herb consumption to later medical problems. Since herbal medicines are regulated as dietary supplements, they are not subject to the premarketing regulatory clearance required for drugs. The burden of proof is on the U.S. Food and Drug Administration to show a dietary supplement is unsafe, unlike for drugs, which cannot be approved until the manufacturer has demonstrated safety and effectiveness.

The effect of risk factor reductions between 1981 and 1990 on coronary heart disease incidence, prevalence, mortality and cost.

OBJECTIVES: We sought to estimate the impact and cost-effectiveness of risk factor reductions between 1981 and 1990. BACKGROUND: Coronary heart disease (CHD) mortality rates have declined dramatically, partly as a result of reductions in CHD risk factors. METHODS: We used the CHD Policy Model, a validated computer-simulation model, to estimate the effects of actual investments made to change coronary risk factors between 1981 and 1990, as well as the impact of these changes on the incidence, prevalence, mortality and costs of CHD during this period and projected to 2015. RESULTS: Observed changes in risk factors between 1981 and 1990 resulted in a reduction of CHD deaths by approximately 430,000 and overall deaths by approximately 740,000, with an estimated cost-effectiveness of about $44,000 per year of life saved during this period, based on the estimated actual costs of the interventions used. However, because much of the benefit of risk factor reductions is delayed, the estimated reductions for the 35-year period of 1981 to 2015 were 3.6 million CHD deaths and 1.2 million non-CHD deaths, at a cost of only about $5,400 per year of life saved. CONCLUSIONS: Aggregate efforts to reduce risk factors between 1981 and 1990 have led to substantial reductions in CHD and should be well worth the cost, largely because of population-wide changes in life-style and habits. Some interventions are much better investments than others, and attention to such issues could lead to better use of resources and better outcomes in the future.

Cost-effectiveness of vitamin therapy to lower plasma homocysteine levels for the prevention of coronary heart disease: effect of grain fortification and beyond.

CONTEXT: A high homocysteine level has been identified as an independent modifiable risk factor for coronary heart disease (CHD) events and death. Since January 1998, the US Food and Drug Administration has required that all enriched grain products contain 140 microg of folic acid per 100 g, a level considered to decrease homocysteine levels. OBJECTIVES: To examine the potential effect of grain fortification with folic acid on CHD events and to estimate the cost-effectiveness of additional vitamin supplementation (folic acid and cyanocobalamin) for CHD prevention. DESIGN AND SETTING: Cost-effectiveness analysis using the Coronary Heart Disease Policy Model, a validated, state-transition model of CHD events in adults aged 35 through 84 years. Data from the third National Health and Nutrition Examination Survey (NHANES III) were used to estimate age- and sex-specific differences in homocysteine levels. INTERVENTION: Hypothetical comparison between a diet that includes enriched grain products projected to increase folic acid intake by 100 microg/d with the same diet without folic acid fortification; and a comparison between vitamin therapy that consists of 1 mg of folic acid and 0.5 mg of cyanocobalamin and the diet that includes grains fortified with folic acid. MAIN OUTCOME MEASURES: Incidence of myocardial infarction and death from CHD, quality-adjusted life-years (QALYs) saved, and medical costs. RESULTS: Grain fortification with folic acid was predicted to decrease CHD events by 8% in women and 13% in men, with comparable reductions in CHD mortality. The model projected that, compared with grain fortification alone, treating all patients with known CHD with folic acid and cyanocobalamin over a 10-year period would result in 310 000 fewer deaths and lower costs. Over the same 10-year period, providing vitamin supplementation in addition to grain fortification to all men aged 45 years or older without known CHD was projected to save more than 300 000 QALYs, to save more than US $2 billion, and to be the preferred strategy. For women without CHD, the preferred vitamin supplementation strategy would be to treat all women older than 55 years, a strategy projected to save more than 140 000 QALYs over 10 years. CONCLUSIONS: Folic acid and cyanocobalamin supplementation may be cost-effective among many population subgroups and could have a major epidemiologic benefit for primary and secondary prevention of CHD if ongoing clinical trials confirm that homocysteine-lowering therapy decreases CHD event rates.

Treatment demands and differential treatment of patients with cystic fibrosis and their siblings: patient, parent and sibling accounts.

Cystic fibrosis (CF) is a progressive disease with no known cure. Advances in diagnosis and treatment have resulted in patients living longer and thus families live with the illness for longer. Treatments are becoming increasingly demanding and are largely performed in the family home. Mothers are often reported to experience greater stress and poorer adjustment than mothers of well children or population norms. Patients and siblings are also reported to display adjustment difficulties. Siblings have rarely been included in research designs. This qualitative study investigates the impact of CF and treatment on eight patients, eight mothers, one father and eight siblings. A family systems perspective was adopted. Each individual was interviewed independently using semistructured interviews. Patients and siblings were aged between 9 and 21 years. Qualitative analyses revealed high levels of non-adherence (intentional and unintentional) and parental involvement in treatment, minimal involvement of siblings, and preferential treatment towards patients. Demanding treatment, coupled with the progressive nature of CF, promote high levels of parental involvement for younger children as well as older teenagers, often due to attempted or actual non-adherence. Siblings may receive less attention while patients' needs take priority. Future development of a measure of adherence suitable for children and adolescents should take into account different motivations for non-adherence, particularly regarding the level of personal control over adherence to treatment. In addition, the potential impact of having a brother or sister with CF should not be underestimated and the needs of siblings should not go unnoticed.

Physical activity in first-degree relatives of breast cancer patients.

This study sought to evaluate physical activity in women at moderate risk for breast cancer, the correlates of engaging in regular physical activity, and whether physical activity relates to psychological well-being. The results revealed that 55% of women were regularly active. Logistic regression models indicated that positive affect was associated with increased and negative affect was associated with decreased overall and leisure activity. Older, married, and employed women were more likely to engage in household/occupational activity, whereas women who perceived their risk for breast cancer as high were less likely. More educated women and those with higher perceived risk were more likely to engage in leisure activity, and married women were less likely. These results suggest a need to increase activity levels in women at moderate risk for breast cancer, provide variables upon which interventions can be tailored to promote activity, and point to psychological benefits of activity in this population.

Health and economic benefits of increased beta-blocker use following myocardial infarction.

CONTEXT: beta-blockers are underused in patients who have myocardial infarction (MI), despite the proven efficacy of these agents. New evidence indicates that beta-blockers can have benefit in patients with conditions that have been considered relative contraindications. Understanding the consequences of underuse of beta-blockers is important because of the implications for current policy debates over quality-of-care measures and Medicare prescription drug coverage. OBJECTIVE: To examine the potential health and economic impact of increased use of beta-blockers in patients who have had MI. DESIGN AND SETTING: We used the Coronary Heart Disease (CHD) Policy Model, a computer-simulation Markov model of CHD in the US population, to estimate the epidemiological impact and cost-effectiveness of increased beta-blocker use from current to target levels among survivors of MI aged 35 to 84 years. Simulations included 1 cohort of MI survivors in 2000 followed up for 20 years and 20 successive annual cohorts of all first-MI survivors in 2000-2020. Mortality and morbidity from CHD were derived from published meta-analyses and recent studies. This analysis used a societal perspective. MAIN OUTCOME MEASURES: Prevented MIs, CHD mortality, life-years gained, and cost per quality-adjusted life-year (QALY) gained in 2000-2020. RESULTS: Initiating beta-blocker use for all MI survivors except those with absolute contraindications in 2000 and continuing treatment for 20 years would result in 4300 fewer CHD deaths, 3500 MIs prevented, and 45,000 life-years gained compared with current use. The incremental cost per QALY gained would be $4500. If this increase in beta-blocker use were implemented in all first-MI survivors annually over 20 years, beta-blockers would save $18 million and result in 72,000 fewer CHD deaths, 62,000 MIs prevented, and 447,000 life-years gained. Sensitivity analyses demonstrated that the cost-effectiveness of beta-blocker therapy would always be less than $11,000 per QALY gained, even under unfavorable assumptions, and may even be cost saving. Restricting beta-blockers only to ideal patients (those without absolute or relative contraindications) would reduce the epidemiological impact of beta-blocker therapy by about 60%. CONCLUSIONS: Our simulation indicates that increased use of beta-blockers after MI would lead to impressive gains in health and would be potentially cost saving. JAMA. 2000;284:2748-2754.

Do medical devices have enhanced placebo effects?

Although the placebo in a clinical trial is often considered simply a baseline against which to evaluate the efficacy of a clinical intervention, there is evidence that the magnitude of placebo effect may be a critical factor in determining the results of a trial. This article examines the question of whether devices have enhanced placebo effects and, if so, what the implications may be. While the evidence of an enhanced placebo effect remains rudimentary, it is provocative and therefore worthy of further study. Suggestions are made, therefore, for how such an effect can be investigated without violating the principles of informed consent.

Cost-effectiveness of cholesterol-lowering therapies according to selected patient characteristics.

BACKGROUND: The National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel II) recommends treatment guidelines based on cholesterol level and number of risk factors. OBJECTIVE: To evaluate how the cost-effectiveness ratios of cholesterol-lowering therapies vary according to different risk factors. DESIGN: Cost-effectiveness analysis. DATA SOURCES: Published data. TARGET POPULATION: Women and men 35 to 84 years of age with low-density lipoprotein cholesterol levels of 4.1 mmol/L or greater (> or =160 mg/dL), divided into 240 risk subgroups according to age, sex, and the presence or absence of four coronary heart disease risk factors (smoking status, blood pressure, low-density lipoprotein cholesterol level, and high-density lipoprotein cholesterol level). TIME HORIZON: 30 years. PERSPECTIVE: Societal. INTERVENTIONS: Step I diet, statin therapy, and no preventive treatment for primary and secondary prevention. OUTCOME MEASURES: Incremental cost-effectiveness ratios. RESULTS OF BASE-CASE ANALYSIS: Incremental cost-effectiveness ratios for primary prevention with step I diet ranged from $1900 per quality-adjusted life-year (QALY) gained to $500000 per QALY depending on risk subgroup characteristics. Primary prevention with a statin compared with diet therapy was $54000 per QALY to $1400000 per QALY. Secondary prevention with a statin cost less than $50000 per QALY for all risk subgroups. RESULTS OF SENSITIVITY ANALYSIS: The inclusion of niacin as a primary prevention option resulted in much less favorable incremental cost-effectiveness ratios for primary prevention with a statin (>$500000 per QALY). CONCLUSIONS: Cost-effectiveness of treatment strategies varies significantly when adjusted for age, sex, and the presence or absence of additional risk factors. Primary prevention with a step I diet seems to be cost-effective for most risk subgroups but may not be cost-effective for otherwise healthy young women. Primary prevention with a statin may not be cost-effective for younger men and women with few risk factors, given the option of secondary prevention and of primary prevention in older age ranges. Secondary prevention with a statin seems to be cost-effective for all risk subgroups and is cost-saving in some high-risk subgroups.

The relative influence of secondary versus primary prevention using the National Cholesterol Education Program Adult Treatment Panel II guidelines.

OBJECTIVES: This study was undertaken to project the population-wide effect of full implementation of the Adult Treatment Panel (ATP) II guidelines of the National Cholesterol Education Program (NCEP). BACKGROUND: The ATP II has proposed guidelines for cholesterol reduction, but the long-term epidemiologic influence of its components has not been fully examined. METHODS: We used a calibrated, validated simulation of the U.S. population, aged 35 to 84 years to estimate the potential for the NCEP guidelines, under varying assumptions, to reduce coronary heart disease morbidity and mortality and overall mortality from the years 2000 to 2020. RESULTS: Primary prevention would yield only about half of the benefits of secondary prevention despite requiring nearly twice as many person-years of treatment. The projected increase in quality-adjusted years of life per year of treatment for secondary prevention was 3- to 12-fold higher than for primary prevention. To yield population-wide epidemiologic benefits equivalent to NCEP recommendations for secondary prevention, primary prevention would require a nearly sixfold increase in the number of persons treated compared with NCEP recommendations. All benefits of universal success of the NCEP primary prevention "screen and treat" guidelines could be achieved by a 11 mg/dl (8%) population-wide reduction in low-density lipoprotein cholesterol levels among persons without preexisting coronary heart disease. CONCLUSIONS: The NCEP guidelines for targeted primary prevention can be a useful component of a rational public health strategy, but only as a complement to the more appealing strategies of secondary prevention and "across-the-board" programs to lower all cholesterol levels.

Cost-effectiveness of donepezil in the treatment of mild or moderate Alzheimer's disease.

OBJECTIVE: To demonstrate the use of cost-effectiveness analysis to assess the economic impact of donepezil in the treatment of mild or moderate AD. BACKGROUND: Cost-effectiveness analyses show the relationship between resources used (costs) and health benefits achieved (effects) for an intervention compared with an alternative strategy. METHODS: We developed a model to estimate the incremental cost-effectiveness of donepezil compared with no treatment. We determined costs per quality-adjusted life-years gained, a measurement that enhances the comparability of diverse studies. The model projects the progression of AD patients into more severe disease stages and into nursing homes. Data from a randomized clinical trial of donepezil were used to assess the drug's impact on the 6-week probabilities of progression. Data on the costs and health-related quality of life associated with different disease stages and settings were taken from published estimates and our companion cross-sectional study, respectively. RESULTS: Donepezil costs are partially offset by a reduction in the costs of care due to enhancement in cognitive functioning and the delay to more costly disease stages and settings. The magnitude of this cost offset and of the effect of donepezil on health-related quality of life depends on the model's assumptions about the duration of the drug effect, where controlled data are lacking. If the drug effect exceeds 2 years, the model predicts that for mild AD the drug would pay for itself in terms of cost offsets. CONCLUSIONS: The results of the cost-effectiveness model presented here suggest that donepezil may be cost-effective but additional controlled data on long-term drug efficacy are needed.

The beta-adrenergic receptor kinase interacts with the amino terminus of the G protein beta subunit.

Desensitization of G protein-coupled receptors involves phosphorylation of the receptors by G protein-coupled receptor kinases, such as the beta-adrenergic receptor kinase (beta ARK). beta ARK activity depends upon its translocation from the cytoplasm to the membrane. The beta gamma subunits of G proteins bind to beta ARK and recruit the kinase to the membrane. The G beta gamma binding domain is localized to a carboxyl terminal region of beta ARK but the beta ARK binding domain of G beta gamma is not known. We used the yeast two-hybrid assay to characterize the interaction between G beta and beta ARK. We demonstrate an interaction between the carboxyl terminus of beta ARK and G beta 2. The strength of this interaction is increased when the VP16 transactivation domain is placed on the carboxyl end of G beta 2, indicating that an accessible G beta 2 amino terminus is important for its interaction with beta ARK. In addition, we show that amino acids 1 to 145 of G beta 2 are sufficient for beta ARK binding.