Effects of a Bacterial Infection on Mitochondrial Function and Oxidative Stress in a Songbird

AbstractAs a major physiological mechanism involved in cellular renewal and repair, immune function is vital to the body's capacity to support tissue maintenance and organismal survival. Because immune defenses can be energetically expensive, the activities of metabolically active organs, such as the liver, are predicted to increase during infection by most pathogens. However, some pathogens are immunosuppressive, which might reduce the metabolic capacities of select organs to suppress immune response. Mycoplasma gallisepticum (MG) is a well-known immunosuppressive bacterium that infects domestic chickens and turkeys as well as songbirds. In the house finch (Haemorhous mexicanus), which is the primary host for MG among songbird species, MG infects both the respiratory system and the conjunctiva of the eye, causing conspicuous swelling. To study the effect of a systemic bacterial infection on cellular respiration and oxidative damage in the house finch, we measured mitochondrial respiration, mitochondrial membrane potential, reactive oxygen species production, and oxidative damage in the livers of house finches that were wild caught and either infected with MG, as indicated by genetic screening for the pathogen, or free of MG infection. We observed that MG-infected house finches showed significantly lower oxidative lipid and protein damage in liver tissue compared with their uninfected counterparts. Moreover, using complex II substrates, we documented a nonsignificant trend for lower state 3 respiration of liver mitochondria in MG-infected house finches compared with uninfected house finches (P=0.07). These results are consistent with the hypothesis that MG suppresses organ function in susceptible hosts.

Mitochondrial physiology varies with parity and body mass in the laboratory mouse (Mus musculus)

The life-history patterns that animals display are a product of their ability to maximize reproductive performance while concurrently balancing numerous metabolic demands. For example, the energetic costs of reproduction may reduce an animal's ability to support self-maintenance and longevity. In this work, we evaluated the impact of parity on mitochondrial physiology in laboratory mice. The theory of mitohormesis suggests that modest exposure to reactive oxygen species can improve performance, while high levels of exposure are damaging. Following this theory, we hypothesized that females that experienced one bout of reproduction (primiparous) would display improved mitochondrial capacity and reduced oxidative damage relative to non-reproductive (nulliparous) mice, while females that had four reproductive events (multiparous) would have lower mitochondrial performance and greater oxidative damage than both nulliparous and primiparous females. We observed that multiple reproductive events enhanced the mitochondrial respiratory capacity of liver mitochondria in females with high body mass. Four-bout females showed a positive relationship between body mass and mitochondrial capacity. In contrast, non-reproductive females showed a negative relationship between body mass and mitochondrial capacity and primiparous females had a slope that did not differ from zero. Other measured variables, too, were highly dependent on body mass, suggesting that a female's body condition has strong impacts on mitochondrial physiology. We also evaluated the relationship between how much females allocated to reproduction (cumulative mass of all young weaned) and mitochondrial function and oxidative stress in the multiparous females. We found that females that allocated more to reproduction had lower basal respiration (state 4), lower mitochondrial density, and higher protein oxidation in liver mitochondria than females that allocated less. These results suggest that, at least through their first four reproductive events, female laboratory mice may experience bioenergetic benefits from reproduction but only those females that allocated the most to reproduction appear to experience a potential cost of reproduction.

Plumage redness signals mitochondrial function in the house finch

Carotenoid coloration is widely recognized as a signal of individual condition in various animals, but despite decades of study, the mechanisms that link carotenoid coloration to condition remain unresolved. Most birds with red feathers convert yellow dietary carotenoids to red carotenoids in an oxidation process requiring the gene encoding the putative cytochrome P450 enzyme CYP2J19. Here, we tested the hypothesis that the process of carotenoid oxidation and feather pigmentation is functionally linked to mitochondrial performance. Consistent with this hypothesis, we observed high levels of red ketolated carotenoids associated with the hepatic mitochondria of moulting wild house finches (Haemorhous mexicanus), and upon fractionation, we found the highest concentration of ketolated carotenoids in the inner mitochondrial membrane. We further found that the redness of growing feathers was positively related to the performance of liver mitochondria. Structural modelling of CYP2J19 supports a direct role of this protein in carotenoid ketolation that may be functionally linked to cellular respiration. These observations suggest that feather coloration serves as a signal of core functionality through inexorable links to cellular respiration in the mitochondria.

Prior reproduction alters how mitochondria respond to an oxidative event

An animal's pace of life is mediated by the physiological demands and stressors it experiences (e.g., reproduction) and one likely mechanism that underlies these effects is oxidative stress. Reproduction has been shown to increase or reduce oxidative stress under different conditions and modify mitochondrial performance. We hypothesized that the changes associated with reproduction can alter how animals respond to future oxidative stressors. We tested this theory by comparing the organ-specific mitochondrial response in female wild-derived house mice. Specifically, we compared mice that reproduced or were virgins to mice that were exposed to an oxidant (i.e., radiation) or not-exposed to radiation. We measured liver and skeletal muscle mitochondrial density, respiratory performance, enzyme activity, and oxidant production, as well as markers of oxidative damage to tissues. In the liver, prior reproduction prevented a radiation-induced reduction in mitochondrial density and increased mitochondrial respiratory performance. In skeletal muscle, prior reproduction resulted in a radiation-induced decline in mitochondrial density which could reduce the bioenergetic capacity of skeletal muscle mitochondria. Yet, electron transport chain complex I activity in skeletal muscle, which dropped with reproduction, returned to control levels following oxidant exposure. The results of this investigation indicate that prior reproduction alters the response of mitochondria to an oxidative challenge in an organ-specific manner. Such changes could have differential effects on future reproductive performance and risk of death.

High activity before breeding improves reproductive performance by enhancing mitochondrial function and biogenesis

Understanding of physiological responses of organisms is typically based on data collected during an isolated event. Although many fundamental insights have been gained from these studies, evaluating the response to a single event ignores the fact that each individual has experienced a unique set of events throughout its life that may have altered its physiology. The idea that prior experiences can influence subsequent performance is known as a carry-over effect. Carry-over effects may explain much of the variation in performance found among individuals. For example, high physical activity has been shown to improve mitochondrial respiratory function and biogenesis and reduce oxidative stress, and has been linked to improved health and longevity. In this study, we asked whether the bioenergetic differences between active and inactive individuals carry over to impact performance in a subsequent reproductive event and alter a female's reproductive outcome. Female mice that had access to a running wheel for a month before mating gave birth to a larger litter and weaned a heavier litter, indicating that high physical activity had a positive carry-over effect to reproduction. Mice that ran also displayed higher mitochondrial respiration and biogenesis with no changes in endogenous antioxidant enzymes. These results provide a mechanistic framework for how the conditions that animals experience before breeding can impact reproductive outcomes.

Common genetic variation near the connexin-43 gene is associated with resting heart rate in African Americans: a genome-wide association study of 13,372 participants

BACKGROUND

Genome-wide association studies have identified several genetic loci associated with variation in resting heart rate in European and Asian populations. No study has evaluated genetic variants associated with heart rate in African Americans.

OBJECTIVE

To identify novel genetic variants associated with resting heart rate in African Americans.

METHODS

Ten cohort studies participating in the Candidate-gene Association Resource and Continental Origins and Genetic Epidemiology Network consortia performed genome-wide genotyping of single nucleotide polymorphisms (SNPs) and imputed 2,954,965 SNPs using HapMap YRI and CEU panels in 13,372 participants of African ancestry. Each study measured the RR interval (ms) from 10-second resting 12-lead electrocardiograms and estimated RR-SNP associations using covariate-adjusted linear regression. Random-effects meta-analysis was used to combine cohort-specific measures of association and identify genome-wide significant loci (P≤2.5×10(-8)).

RESULTS

Fourteen SNPs on chromosome 6q22 exceeded the genome-wide significance threshold. The most significant association was for rs9320841 (+13 ms per minor allele; P = 4.98×10(-15)). This SNP was approximately 350 kb downstream of GJA1, a locus previously identified as harboring SNPs associated with heart rate in Europeans. Adjustment for rs9320841 also attenuated the association between the remaining 13 SNPs in this region and heart rate. In addition, SNPs in MYH6, which have been identified in European genome-wide association study, were associated with similar changes in the resting heart rate as this population of African Americans.

CONCLUSIONS

An intergenic region downstream of GJA1 (the gene encoding connexin 43, the major protein of the human myocardial gap junction) and an intragenic region within MYH6 are associated with variation in resting heart rate in African Americans as well as in populations of European and Asian origin.

Telomeres in the chicken: genome stability and chromosome ends

Telomeres are the complex nucleoprotein structures at the termini of linear chromosomes. Telomeric DNA consists of a highly conserved hexanucleotide arranged in tandem repeats. Telomerase, a ribonucleoprotein of the reverse transcriptase family, specifies the sequence of telomeric DNA and maintains telomere array length. Numerous studies in model organisms established the significance of telomere structure and function in regulating genome stability, cellular aging, and oncogenesis. Our overall research objectives are to understand the organization of the telomere arrays in chicken in the context of the unusual organization and specialized features of this higher vertebrate genome (which include a compact genome, numerous microchromosomes, and high recombination rate) and to elucidate the role telomeres play in genome stability impacting cell function and life span. Recent studies found that the chicken genome contains three overlapping size classes of telomere arrays that differ in location and age-related stability: Class I 0.5 to 10 kb, Class II 10 to 40 kb, and Class III 40 kb to 2 Mb. Some notable features of chicken telomere biology are that the chicken genome contains ten times more telomeric DNA than the human genome and the Class III telomere arrays are the largest described for any vertebrate species. In vivo, chicken telomeres (Class II) shorten in an age-related fashion and telomerase activity is high in early stage embryos and developing organs but down-regulates during late embryogenesis or postnatally in most somatic tissues. In vitro, chicken cells down-regulate telomerase activity unless transformed. Knowledge of chicken telomere biology contributes information relevant to present and future biotechnology applications of chickens in vivo and chicken cells in vitro.

Is the donut in front of the car? An electrophysiological study examining spatial reference frame processing

The process of describing an object's location relative to another object results in ambiguity. How do people handle this ambiguity? The present studies examined spatial language processing when use of different reference frames results in ambiguity. We investigated whether electrophysiological (ERP) measures of cognitive processing may elucidate underlying reference frame processing; in particular, we were interested in semantic integration. ERP results showed a larger N400, peaking between 300 and 375 ms, when the intrinsic frame was not used. Behavioural results mirrored this finding, indicating a reduced cognitive processing requirement for the intrinsic reference frame. Previous work has not definitively tied spatial reference frame processing to specific ERP components and their associated cognitive processes. Although the N400 peak seen in this data is early, additional work supports the N400 interpretation, thereby linking spatial frame processing to semantic integration. Results are discussed within the larger context of spatial reference frame processing.

Ontogeny of telomerase in chicken: impact of downregulation on pre- and postnatal telomere length in vivo

Telomeres are the termini of linear chromosomes composed of tandem repeats of a conserved DNA sequence. Telomerase provides a mechanism for proliferating cells to offset telomeric sequence erosion by synthesizing new repeats onto the end of each parental DNA strand. Reduced or absent telomerase activity can lead to telomere shortening and genome instability. Telomeres and telomerase have not previously been characterized during ontogeny of any avian species. In the present study, telomerase activity in the chicken model was examined from early differentiation embryos through to adulthood. Telomerase activity was detected in all early embryos (preblastula through neurula) and in tissues throughout organogenesis. Subsequently, telomerase was downregulated in the majority of somatic tissues, either pre- or postnatally. A subset of tissues, such as intestine, immune and reproductive organs, exhibited constitutive activity. The impact of telomerase downregulation on telomere length was investigated and a telomere reduction of 3.2 kb in somatic tissues compared with germ line was observed in 5-year-old adults. The present results suggest that the telomere clock function is a conserved feature of avians as well as mammals. Knowledge regarding the relationships among telomerase regulation, proliferation/senescence profiles and differentiation status will be useful for numerous applications of chicken cells.

Not all narrative shifts function equally

Readers of narratives keep track of narrative events and the information associated with these events. Does some of this associated information help structure the processing of and memory for the narrative? In three experiments, we examined the role of basic event building blocks (character, time, and location) in event indexing during text comprehension. These three experiments dealt with perceived coherence, perceived cohesion, and on-line processing, respectively. The results indicated that characters are more likely to serve as event indexes. Although the findings with respect to indexing were similar in all three experiments, interesting differences emerged as a function of the level of text comprehension examined (coherence, cohesion, or on-line processing).

"Aha" effects in the generation of pictures

An "aha" effect in memory was first reported by Auble, Franks, and Soraci (1979). They demonstrated that recall was greater for sentences that were initially incomprehensible but which were eventually comprehended, as compared with sentences that were understood from the outset. The present studies extend this "aha" effect to memory for pictorial stimuli. In Experiment 1, a recall advantage for pictures encoded by connecting the dots as compared with those encoded by tracing or visual scanning occurred only in the absence of foreknowledge of the picture (i.e., an "aha" effect). In Experiment 2, we replicated this finding and obtained evidence that conceptually based, verbal foreknowledge does not function in a similar manner as does pictorial foreknowledge in suppressing the "aha" recall advantage. These results place important constraints on previous research on generation effects for visual stimuli and attest to the cross-modal generalizability of the "aha" effect.

Treatment of human immunodeficiency virus during pregnancy: the shift from an exclusive focus on fetal protection to a more balanced approach

A review is presented of policy and treatment guidelines for human immunodeficiency virus infection in pregnancy. Interventions that serve the best interests of pregnant women and their fetuses are suggested. Reproductive studies with animals should be done routinely, and more research with pregnant women should be conducted. Women and their health care providers need to shift away from the "therapeutic nihilism" paradigm. All clinical decisions must be made cautiously and thoughtfully, with the understanding that the health needs of the pregnant woman are usually whatever is in the best interest of the developing fetus.

Rising levels of cardiovascular mortality in Mississippi, 1979-1995

BACKGROUND

Cardiovascular disease rates are improving in the United States, but not for certain subgroups, especially some African Americans. The objective of the study is to assess current levels and trends in cardiovascular disease mortality in Mississippi.

METHODS

Mortality statistics from the U.S. vital statistics system for the period 1979-95 were used. Comparison of age-adjusted mortality rates in Mississippi with the other states for the year 1995 and with the nation as a whole over the period of 1979-95 was performed.

RESULTS

Mississippians had the highest age-adjusted cardiovascular disease morality rates in the nation in 1995. Overall, the cardiovascular rates in Mississippi were 37% higher than for the U.S. African American men and women from Mississippi had especially high cardiovascular mortality rates, approximately 50% and 70% higher than their white counterparts, respectively. The higher burden of cardiovascular disease in African Americans from Mississippi was especially marked in the younger age groups. Since about 1984-85, cardiovascular mortality rates in Mississippi have been increasing for African Americans, whereas nationally they have been decreasing. In contrast, cardiovascular mortality rates for whites in Mississippi have been declining, but at a much slower rate than seen nationally. The wide divergence in trends for African American and white men and women over that period in Mississippi has lead to an estimated 19,400 excess cardiovascular deaths. Virtually identical trends were found for heart disease.

CONCLUSIONS

Cardiovascular diseases are a major public health problem in Mississippi that is especially severe in African American residents, and the problem is growing worse each year. It is important to identify the determinants of and solutions for this enormous public health problem in Mississippi.

Sexual activity and the cardiovascular patient: guidelines

Modern cardiac rehabilitation is a comprehensive program of secondary prevention for patients with heart disease. Moreover, it is an important context in which to broach issues of impaired sexual function. Sexual problems plague a large portion of our cardiac patient population. Unspoken+ concerns about impotence, now more correctly called erectile dysfunction (ED), are common, as are concerns about the safety of engaging in sexual activity, especially after major cardiac events or therapeutic interventions. A large proportion of patients do not return to normal sexual activity after a cardiac event. Many factors, including normal age-related changes in sexual response, medication-induced dysfunction, and vascular changes associated with risk factors (e.g., diabetes and dyslipidemia), as well as the emotional impact of symptomatic heart disease, may influence sexual function in these patients. These factors, occurring alone or in combination, probably explain the discouraging prevalence of sexual dysfunction in patients with manifest cardiac disease. Because so few patients have specific cardiac reasons for limiting sexual activity, a clear opportunity exists for cardiologists and their staff to help enhance the emotional well-being and overall quality of life of their cardiac patients.

Relationship among mental stress-induced ischemia and ischemia during daily life and during exercise: the Psychophysiologic Investigations of Myocardial Ischemia (PIMI) study

OBJECTIVES

The purposes of this database study were to determine: 1) the relationship between mental stress-induced ischemia and ischemia during daily life and during exercise; 2) whether patients who exhibited daily life ischemia experienced greater hemodynamic and catecholamine responses to mental or physical stress than patients who did not exhibit daily life ischemia, and 3) whether patients who experienced daily life ischemia could be identified on the basis of laboratory-induced ischemia using mental or exercise stress testing.

BACKGROUND

The relationships between mental stress-induced ischemia in the laboratory and ischemia during daily life and during exercise are unclear.

METHODS

One hundred ninety-six stable patients with documented coronary disease and a positive exercise test underwent mental stress testing and bicycle exercise testing. Radionuclide ventriculography and electrocardiographic (ECG) monitoring were performed during the mental stress and bicycle tests. Patients underwent 48 h of ambulatory ECG monitoring. Hemodynamic and catecholamine responses were obtained during mental stress and bicycle tests.

RESULTS

Ischemia (reversible left ventricular dysfunction or ST segment depression > or = 1 mm) developed in 106 of 183 patients (58%) during the mental stress test. There were no significant differences in clinical characteristics of patients with, compared with those without, mental stress-induced ischemia. Patients with mental stress ischemia more often had daily life ischemia than patients without mental stress ischemia, but their exercise tests were similar. Patients with daily life ischemia had higher ejection fraction and cardiac output, and lower systemic vascular resistance during mental stress than patients without daily life ischemia. Blood pressure and catecholamine levels at rest and during the mental stress tests were not different in patients with, compared with those without, daily life ischemia. Patients with daily life ischemia had a higher ejection fraction at rest and at peak bicycle exercise compared with patients without daily life ischemia, but there were no other differences in peak hemodynamic or catecholamine responses to exercise. The presence of ST segment depression during routine daily activities was best predicted by ST segment depression during mental or bicycle exercise stress, although ST segment depression was rare during mental stress.

CONCLUSIONS

Patients with daily life ischemia exhibit a heightened generalized response to mental stress. ST segment depression in response to mental or exercise stress is more predictive of ST segment depression during routine daily activities than other laboratory-based ischemic markers. Therapeutic management strategies might therefore focus on patients with these physiologic responses to stress and on whether lessening such responses reduces ischemia.

Barriers to informed consent

OBJECTIVES

To provide oncology nurses with a review of barriers that may limit the ability of adults to provide informed consent.

DATA SOURCES

Published articles, research studies, and review articles pertaining to informed consent and clinical research.

CONCLUSIONS

Patient-centered barriers to informed consent (such as age, education, and illness) and process-centered barriers (such as content and readability of the consent form, timing of discussion, and amount of time allotted to the process) can affect an individual's ability to provide substantial informed consent.

IMPLICATIONS FOR NURSING PRACTICE

Oncology nurses must be aware and knowledgeable of the various barriers to informed consent to minimize these barriers and to improve and facilitate the informed consent process.

Goal-specific influences on the representation of spatial perspective

In two experiments, subjects learned an unfamiliar campus environment, either by studying a map or by navigating. During acquisition, the subjects had one of two spatial goals: to learn the layout of the building (survey goal) or to learn the fastest routes between locations (route goal). Spatial memory was tested with several tasks, some assessing survey perspective processing and some assessing route perspective processing. Results indicate multiple influences on the representation of spatial perspective. Learning condition influenced performance. Individuals studying maps gave more accurate responses to some survey perspective tasks, whereas individuals navigating gave more accurate responses to some route perspective tasks. Spatial goals also influenced performance. Having a route goal enhanced performance on route perspective tasks; having a survey goal enhanced performance on survey perspective tasks. These findings are discussed in the context of research indicating flexibility when processing spatial perspective. Individuals can use spatial information from different perspectives, often doing so in a goal-directed manner.

Management and outcomes for black patients with acute myocardial infarction in the reperfusion era. National Registry of Myocardial Infarction 2 Investigators

Data from a national registry of myocardial infarction patients from June 1994 to April 1996 were analyzed to compare the presenting characteristics, acute reperfusion strategies, treatment patterns, and clinical outcomes among black and white patients. Blacks presented much later to the hospital after the onset of symptoms (median 145 vs 122 minutes, p <0.001), were more likely to have atypical cardiac symptoms (28% vs 24%, p <0.001), and nondiagnostic electrocardiograms during the initial evaluation period compared with whites (37% vs 31%, p <0.001). Also, blacks were less likely to receive intravenous thrombolytic therapy (adjusted odds ratio [OR] 0.76, 95% confidence intervals [CI] 0.71 to 0.80), coronary arteriography (adjusted OR 0.85, 95% CI 0.77 to 0.95), other elective catheter-based procedures (adjusted OR 0.87, 95% CI 0.78 to 0.96), and coronary artery bypass surgery (adjusted OR 0.66, 95% CI 0.58 to 0.75) than their white counterparts. Despite these differences in treatment, there were no significant differences in hospital mortality between blacks and whites.

Presenting characteristics, treatment patterns, and clinical outcomes of non-black minorities in the National Registry of Myocardial Infarction 2

Data from a national registry (cohort) of myocardial infarction, which has enrolled 275,046 patients from June 1994 to April 1996, were analyzed to compare the baseline demographic and clinical characteristics, treatment patterns, and clinical outcomes among Hispanics, Asian-Pacific islanders, and native Americans with those of white Americans presenting to the hospital with acute myocardial infarction. Non-black minorities were younger, had a higher proportion of men, used the emergency medical services less frequently, and presented later to the hospital after the onset of symptoms (135 vs 122 minutes, p <0.001) than whites. Also, non-black minorities were less likely to receive beta-blocker therapy at discharge (crude odds ratio 0.86, confidence interval 0.82 to 0.90) than whites, but they were generally as likely to receive intravenous thrombolytic therapy (with the exception of Asian-Pacific islanders) and undergo both coronary arteriography and revascularization procedures as their white counterparts. There were no significant differences in hospital mortality for non-black minorities compared with whites.

Ethnic disparities in patient recall of physician recommendations of diagnostic and treatment procedures for coronary disease

Despite the proven benefits of many cardiac procedures, some are used less frequently for African Americans than for white patients with known or suspected coronary disease. This study explored differences between ethnic groups that may affect patient recall of physician recommendations of cardiac procedures. Also examined were patients' responses when asked about adhering to those recommendations. The data examined were collected from interviews with 1,333 African American and white hospital inpatients with known coronary disease admitted to the Birmingham-Black Health Seeking for Coronary Heart Disease Project (1989-1990) in Alabama. Respondents were asked to recall previous health care encounters, physician recommendations of cardiac procedures, and adherence to those recommendations. Compared with whites, fewer African American patients recalled physicians recommending some cardiac procedures. If procedure recommendations were recalled, no ethnic differences were found in patient recall of adhering to those recommendations. Predictors of recall of the recommended procedures were identified by multivariate logistic regression. Patients' knowledge of having coronary disease was the common factor that predicted their recall of all cardiac procedures. Other predictor variables included some cardiac risk factors and symptoms, socioeconomic status, and ethnicity. Although health care practice is influenced by many factors, it is important to examine variables that may lead to a reduction in ethnic disparities in coronary disease morbidity and mortality.

Constitutional del(19)(q12q13.1) in a three-year-old girl with severe phenotypic abnormalities affecting multiple organ systems

We present the clinical, cytogenetic, and molecular studies on a constitutional deletion of 19q ascertained prenatally due to decreased fetal activity and IUGR. Chromosome analysis by GTG banding on amniocytes suggested a del(19)(q13.1q13.3), but the analysis of microsatellites by PCR demonstrated that the deletion involved the distal segment of q12 and the proximal segment of q13.1 (15 cM). The severely affected female infant born at 38 weeks has clinical findings that may be related to haploinsufficiency of specific genes within 19q12.1-->q13.1 that control important processes of normal development and cell function.

Maternity care practices of navy family practice residency graduates after leaving the military

BACKGROUND

Nationwide, 32% of residency-trained family physicians deliver babies compared with 73% to 90% in the military. This study describes and defines issues that could ultimately help revive family practice maternity care.

METHOD

We surveyed 112 family physicians who had left the navy.

RESULTS

Ninety-one percent had delivered babies in the navy, 45% since leaving the military, and 25% currently. Principal maternity care incentives both in and out of the military were personal and professional satisfaction. Reasons for not providing civilian maternity care included malpractice risks, insurance costs, and lifestyle issues. The decision for providing maternity care was usually made before or during residency, whereas the decision against was most often made upon leaving the military. Among more recent graduates (1990-1995), 48% continued to deliver babies in civilian practice. (This is about 20% more than recent civilian graduates.) Malpractice concerns were less important to this group than to earlier graduates.

CONCLUSIONS

Factors discouraging family physicians from providing maternity care arise from their practice environment and are not easily overcome with improved training and experience. Recent navy residency graduates are not as easily discouraged.

Reported comfort with obstetrical emergencies before and after participation in the advanced life support in obstetrics course

BACKGROUND AND OBJECTIVES

Prior research has demonstrated a change in Advanced Life Support in Obstetrics (ALSO) course attendees' reported comfort with managing specific obstetrical emergencies and procedures before and immediately after participation in an ALSO course. Assessment of longer-term stability of these changes has not been performed. This study measured changes in comfort with obstetrical emergencies and reported practice patterns 1 year after ALSO training.

METHODS

ALSO course attendees (275) were given a grounded Likert scale survey measuring reported comfort with the management of specific obstetrical emergencies and procedures before, immediately after, 6 months after, and 1 year after participation in an ALSO course. Practice patterns were also surveyed. Paired data were analyzed using the Kruskal-Wallis one-way ANOVA test at a 95% confidence interval for two-tailed significance.

RESULTS

ALSO course participants reported a significant increase in their comfort with the management of each of 15 obstetrical emergencies and procedures taught in the ALSO curriculum. Reported comfort remained high at 6 months' and 1-year follow-up and was accompanied by a statistically significant change in reported practice patterns; more participants performed, in their practice 1 year after completion of ALSO training, amnioinfusion, vacuum-assisted vaginal delivery, and ultrasound for determining fetal position and placental location.

CONCLUSIONS

Affective learning is important in translating knowledge and skills into the practice of medicine. Our study demonstrates that participation in the ALSO course increases participants' knowledge in the affective domain of learning.

Perceived characteristics of successful family practice residency maternity care training programs

BACKGROUND AND OBJECTIVES

This study determined the perceived characteristics of family practice residency training programs that produce a high percentage of graduates who provide maternity care.

METHODS

We surveyed a Delphi panel of 28 family practice maternity care experts.

RESULTS

Consensus was reached after the third survey. The characteristics of the family medicine faculty and teaching service were rated as most important. Other essential characteristics were an adequate obstetrical training volume; mutual respect between obstetric and family medicine faculty and residents; support for family practice maternity care from obstetricians, administration, and nursing staff; and family physicians being accepted in the community as maternity care providers.

CONCLUSIONS

Family practice residency programs that produce a high percentage of graduates who provide maternity care have a unique, family practice maternity care-friendly environment. Residency programs wishing to increase the percentage of their graduates who provide maternity care should ensure that their faculty support family practice maternity care, are competent in maternity care, and model maternity care in their own practices. They should strive to ensure an adequate volume of obstetrical cases for resident education and work toward educating patients and local obstetricians, nursing staff, and hospital administration regarding family practice maternity care.

The maternity care practice of Navy family practice residency graduates while on active duty

BACKGROUND AND OBJECTIVES

Military family practice residency programs produce a high percentage of graduates who provide maternity care. This study will define the scope of maternity care practice for one military family practice residency program's graduates while they were serving on active duty in the U.S. Navy.

METHODS

Two hundred eight surviving graduates of the family practice residency at Naval Hospital, Jacksonville, Florida, from 1971 to 1995 were surveyed by mail regarding their maternity care practice while on active duty. One hundred eighty-one (87%) responded to the survey, and the data were analyzed with descriptive statistics.

FINDINGS

The vast majority of these Navy family practice residency graduates provided prenatal care (88.4%) and routine vaginal delivery services (85.1%) while on active duty. The majority repaired third- and fourth-degree perineal lacerations and performed vacuum- or forceps-assisted vaginal delivery. Additionally, a significant minority provided more advanced maternity care services such as dilation and curettage, tubal ligation, and cesarean section. The overwhelming majority (97%) of these graduates felt that their residency education had adequately prepared them to provide these maternity care services while on active duty.

CONCLUSIONS

During the past 25 years, Navy residency-trained family physicians provided a wide range of maternity care services while on active duty and felt that their Navy residency training program had prepared them well to meet this responsibility.

Indexing events in memory: evidence for index dominance

Research on narrative comprehension and autobiographical memory converge on three hypotheses which make different predictions about event organisation. The availability of different event components as indexes may explain the convergence on three hypotheses rather than one. In this paper, three experiments assessed event indexing in narratives with different available indexes. In Experiment 1, participants read event descriptions organised by character or time. In Experiment 2, event descriptions were organised by character or location. In Experiment 3, participants read event descriptions where events were grouped by activity. In each experiment, memory could be organised by any of the available components alone, by both components, or by using the organisation imposed by the discourse. Participants indexed events by character in Experiment 1, re-indexing information when necessary. Results of Experiment 2 indicated equal use of character and location indexes. In this case, participants used the discourse organisation. In Experiment 3, participants indexed events using activity groupings, again re-indexing events when necessary. Results are interpreted as indicating reliance on a single organising index with flexibility in the selection of different event components as indexes.

beta-Galactosidase gene mutations in patients with slowly progressive GM1 gangliosidosis

Three unrelated North American cases with slowly progressive forms of GM1 gangliosidosis were found to have two unique point mutations and a 9 bp insertion in the coding region of the gene encoding beta-galactosidase. Case 1 was noted to have a 9 bp insertion ¿CAGAATTTT¿ on one allele between nucleotides 730 and 731 with no other mutations identified in the other allele. In case 2, two point mutations were found: a unique G-->A transition at nucleotide 602 causing an Arg-->His substitution in codon 201 (mutation R201H); and a previously identified G-->T transition at nucleotide 1527 causing a Trp-->Cys substitution in codon 509 (mutation W509C), which has been noted in adult and chronic forms of GM1 gangliosidosis. Case 3 had a unique point mutation (A-->G transition at nucleotide 797) resulting in a Asn-->Ser amino acid substitution in codon 266 (mutation N266S), with no other mutations found in the same or the other allele. Single-strand conformation polymorphism performed on over 100 controls did not demonstrate the presence of the point mutations R201H or N266S. Also, the mutant proteins coded by the two point mutations did not show enzymatic activity in the Cos-1 cell expression system confirming that these mutations are associated with low enzyme activity.

Long-term survival of African Americans in the Coronary Artery Surgery Study (CASS)

OBJECTIVES

This study sought to determine the long-term (> 15 years) outcome of a clinically well characterized cohort of African Americans with known or suspected coronary artery disease (CAD).

BACKGROUND

The mortality rate from CAD is higher in African Americans than in whites. An earlier analysis of data from the Coronary Artery Surgery Study (CASS) registry suggested that African American and white patients treated surgically had equal 5-year survival rates.

METHODS

Survival data from the CASS registry were analyzed to determine whether 1) African American race is an independent predictor of mortality; and 2) initial therapy is predictive of mortality among African American patients.

RESULTS

Overall, 60% of white and 52% of African American patients survived 16 years (p < 0.00001). Multivariate Cox models confirmed that African American race was independently associated with higher mortality in both the medical group (hazard ratio [HR] 1.34, 95% confidence interval [CI] 1.11 to 1.63) and the surgical group (HR 1.63, 95% CI 1.19 to 2.23). Initial therapy was not predictive of survival among African American patients (p = 0.81). However, smoking status significantly influenced survival: African Americans who did not smoke experienced significantly improved survival (60% vs. 48% for smokers), which equaled survival for white nonsmokers (61%, p = NS).

CONCLUSIONS

In contrast to results from shorter term studies, African Americans experienced higher overall mortality rates than whites over the long term, regardless of the type of initial treatment. Survival among nonsmoking African Americans at 16 years equaled survival among nonsmoking whites.

Providing the Advanced Life Support in Obstetrics Course within the military family practice training system

"The Advanced Life Support in Obstetrics (ALSO) Course is designed to assist health professionals in developing and maintaining the knowledge and skills they will need to effectively manage the emergencies which arise in obstetrics." Given the fact that the vast majority of military family physicians provide maternity care, often in small overseas facilities without in-hospital obstetrician backup, inclusion of this course into the military family practice residency training curriculum would be very beneficial to the mission of family practice within the military. A brief background of the ALSO movement and the ALSO course curriculum are provided. Lessons learned to aid military family practice departments in providing quality ALSO courses are described, as are arguments for the inclusion of ALSO training into military family practice training curriculums.

Harms of excluding pregnant women from clinical research: the case of HIV-infected pregnant women

Since the beginning of the AIDS epidemic, the proportion of AIDS cases among women has continued to rise. Women constituted 23 percent of the AIDS cases reported to the Centers for Disease Control and Prevention (CDC) in 1995, and 81 percent of these women were of childbearing age (13 to 44 years). It was not until 1991, however, that epidemiological studies of women were initiated. By comparison, the representation of HIV-infected women in clinical trials gradually has grown. Undoubtedly, a consequence of the increased numbers of women in clinical and epidemiological research is the earlier identification of and more appropriate treatments for HIV-related syndromes when women present in the clinical setting. Despite this expanded focus on women, however, clear information to guide the treatment of HIV-infected women who are pregnant is still lagging behind.

Comparison of surgical and medical group survival in patients with left main coronary artery disease. Long-term CASS experience

BACKGROUND

Observational and randomized studies designed to compare surgical and medical therapies in patients with left main coronary artery disease (LMCD) have shown that coronary artery bypass graft (CABG) surgery prolongs life in most patients with LMCD. The present report of 1484 patients with LMCD in the Coronary Artery Surgery Study (CASS) Registry extends the originally published 5-year surgical and medical group survival analysis to more than 16 years of follow-up and permits analysis of LMCD patient subgroups.

METHODS AND RESULTS

The CASS Registry contains 1484 patients with > or = 50% left main coronary artery stenosis initially treated with either surgical or nonsurgical therapy. The 15-year cumulative survival estimates were 37% for the 1153 patients in the surgical group compared with 27% for the 331 patients in the medical group. Median survival in the surgical group was 13.3 years (12.8 to 13.8 years, 95% confidence limits) compared with only 6.6 years (5.4 to 7.9 years) in the medical group (difference, 6.7 years; P < .0001). Median survival was also significantly longer in the surgical group stratified by age, sex, anginal class, left ventricular (LV) function, coronary anatomy, and the extent of LMCD. However, CABG surgery did not significantly prolong median survival in patient subgroups with (1) left main coronary stenosis of 50% to 59%; (2) normal LV systolic function; (3) normal or mildly abnormal LV systolic function and a right coronary artery stenosis > or = 70%; and (4) a nonstenotic (< or = 70%) right coronary artery. The 15-year cumulative survival for patients with normal LV systolic function in the surgical and medical groups was 42% and 51%, respectively. Median survival was 14.7 years in the surgical group and > 15 years in the medical group (P = NS). In patients with normal LV systolic function and a right coronary artery stenosis > or = 70%, the 15-year cumulative survival rates were also similar in the surgical and medical groups (40% and 48%, respectively). Median survival was 14.3 years in the surgical group and 14.2 years in the medical group (P = NS). The 15-year cumulative survival estimates for all subgroups were affected by convergence of the surgical and medical survival group curves owing to a disproportionate increase in the late surgical group mortality. Overall, 25% of patients in the medical group ultimately underwent CABG surgery. If all medical group patients had survived long enough, about 47% would be estimated to have had surgery by 15 years.

CONCLUSIONS

This report, which extends follow-up of more than 16 years in CASS Registry patients with LMCD, shows that CABG surgery prolongs life in most clinical and angiographic subgroups. However, median survival was not prolonged by CABG surgery in patients with normal LV systolic function, even if a significant right coronary artery stenosis (> or = 70%) also was present. These results extend our understanding of the natural history of LMCD and permit a more accurate estimate of long-term surgical and medical group survival.

Comparison of surgical and medical group survival in patients with left main equivalent coronary artery disease. Long-term CASS experience

BACKGROUND

Combined severe proximal left anterior descending and proximal left circumflex coronary artery disease, or left main equivalent (LMEQ) disease, defines a prognostic high-risk angiographic subset of patients with chronic ischemic heart disease. While numerous observational and randomized clinical trials showed prolonged survival in surgically compared with medically treated patients with left main coronary artery disease, relatively few observational studies compared surgical and medical therapies in patients with LMEQ disease. The present report of 912 patients with LMEQ disease in the Coronary Artery Surgery Study (CASS) Registry extends the originally published 5-year surgical and medical group survival analysis to more than 16 years of follow-up and permits analysis of LMEQ patient subgroups.

METHODS AND RESULTS

The CASS Registry contains 912 patients with LMEQ disease, defined as combined stenoses of > or = 70% in the proximal left anterior descending coronary artery before the first septal perforator and proximal circumflex coronary artery before the first obtuse marginal branch, initially treated with either surgical or nonsurgical therapy. The 15-year cumulative survival estimates were 44% for the 630 patients in the surgical group and 31% for the 282 patients in the medical group. Median survival in the surgical group was 13.1 years (12.7 to 14.1 years, 95% confidence limits) compared with only 6.2 years (4.8 to 7.9 years) in the medical group (difference, 6.9 years; P < .0001). Median survival was also significantly longer in the surgical group stratified by age, sex, anginal class, left ventricular (LV) function, and coronary anatomy. However, coronary artery bypass graft (CABG) surgery did not significantly prolong median survival in patient subgroups with (1) normal LV systolic function, even if a significant right coronary artery stenosis (> or = 70%) also was present, and (2) mildly abnormal (LV score, 6 to 10) LV systolic function. The 15-year cumulative survival in patients with normal LV systolic function in the surgical and medical groups was 63% and 54%, respectively. Median survival was > 15 years in both the surgical and medical groups (P = NS). In patients with normal LV systolic function and right coronary artery stenosis > or = 70%, the 15-year cumulative survival was also similar in the surgical and medical groups (63% and 53%, respectively). Median survival was > 15 years in both the surgical and medical groups (P = NS). The 15-year cumulative survival estimates in all subgroups were affected by convergence of the surgical and medical group survival curves caused by a disproportionate increase in late surgical group mortality. Overall, 26% of patients in the medical group ultimately underwent CABG surgery. If all medical group patients had survived long enough, about 65% would be estimated to have had surgery by 15 years. When the CASS Registry patients with LMEQ disease who participated in the randomized trial or who were randomizable were analyzed, CABG surgery did not prolong the 15-year cumulative survival estimates compared with nonsurgical therapy for randomized (71% versus 67%, respectively) and for randomizable patients (62% versus 92%, respectively) with an LV ejection fraction > or = 50%.

CONCLUSIONS

This report, which extends follow-up of more than 16 years in CASS Registry patients with LMEQ disease, shows that CABG surgery prolongs life in most clinical and angiographic subgroups. However, median survival was not prolonged by CABG surgery in patients with normal LV systolic function, even if a significant right coronary artery stenosis (> or = 70%) also was present or in patients with an LV ejection fraction > or = 50% who participated in the CASS randomized trial or who were randomizable.

Race and sex differences in rates of invasive cardiac procedures in US hospitals. Data from the National Hospital Discharge Survey

BACKGROUND

Lower rates of invasive cardiac procedures have been reported for blacks and women than for white men. However, few studies have adjusted for differences in the type of hospital of admission, insurance status, and disease severity. SETTING, DESIGN, AND PARTICIPANTS: Data from the National Hospital Discharge Survey were used to investigate race and sex differences in rates of cardiac catheterization, percutaneous transluminal coronary angioplasty, and coronary artery bypass surgery among 10,348 persons hospitalized for acute myocardial infarction.

RESULTS

White men consistently had the highest procedure rates, followed by white women, black men, and black women. After matching for the hospital of admission and adjusting for age, in-hospital mortality, health insurance, and hospital transfer rates (with white men as the referent), the odds ratios for cardiac catheterization were 0.67 (95% confidence interval [CI], 0.51 to 0.87) for black men, 0.72 (95% CI, 0.63 to 0.83) for white women, and 0.50 (95% CI, 0.37 to 0.68) for black women. Similar race-sex differences were noted for percutaneous transluminal coronary angioplasty and coronary artery bypass surgery.

CONCLUSIONS

Race and sex differentials in the rates of invasive cardiac procedures remained despite matching for the hospital of admission and controlling for other factors that influence procedure rates, suggesting that the race and sex of the patient influence the use of these procedures.

Expression of PAI-1, t-PA and u-PA in cultured human umbilical vein endothelial cells derived from racial groups

To determine whether inherent fibrinolytic differences may exist in racial groups (black americans, BA vs. white americans, WA), 55 different individual racially-derived human umbilical vein endothelial cell (HUVEC) cultures (35 BA and 20 WA) were analyzed in terms of their fibrinolytic protein (t-PA, u-PA and PAI-1) antigen and mRNA levels. Values (mean +/- SD) for measured fibrinolytic component levels include: cell-associated t-PA antigen (ELISA), 1.14 +/- 0.82 ng/ml/8.6 x 10(5) cells/24 hr in BA and 0.70 +/- 0.85 ng/ml in WA (p = 0.0624); secreted t-PA antigen, 18.65 +/- 17.06 ng/ml in BA and 10.37 +/- 6.38 ng/ml in WA (p = 0.0422); t-PA/cyclophilin mRNA ratios (Northern blot analysis), 1.90 +/- 1.34 in BA and 1.32 +/- 0.70 in WA (p = 0.0776); cell-associated PAI-1 antigen, 71.10 +/- 30.16 ng/ml/8.6 x 10(5) cells/24 hr in BA and 108.85 +/- 56.89 ng/ml in WA (p = 0.0022); secreted PAI-1 antigen, 1,582.13 +/- 612.67 ng/ml in BA and 1,992.17 +/- 711.50 ng/ml in WA (p = 0.0285); 2.4 kb PAI-1/cyclophilin mRNA ratios, 0.59 +/- 0.39 in BA and 0.79 +/- 0.31 in WA (p = 0.1085); 3.4 kb PAI-1/cyclophilin mRNA ratios, 0.70 +/- 0.47 in BA and 0.77 +/- 0.54 in WA (p = 0.6322). These combined data suggest that cultured HUVECs from BA express significantly higher levels of t-PA, lower levels of PAI-1 and approximately 1.72-fold lower molar ratio of PAI-1/t-PA antigen (183.99 +/- 168.81 vs. 315.92 +/- 164.99) (p < 0.05) than cultured HUVECs from WA, presumably reflecting an apparent inherent increased fibrinolytic potential in cultured HUVEC derived from BA.

Race and prognosis after myocardial infarction. Results of the thrombolysis in myocardial infarction (TIMI) phase II trial

BACKGROUND

To better understand the role of race/ethnicity in survival after acute myocardial infarction, we compared clinical and laboratory data, response to thrombolytic therapy, and clinical outcome in 2885 patients participating in the Thrombolysis in Myocardial Infarction Phase II (TIMI II) Trial among three groups of patients (2564 whites, 174 blacks, and 147 Hispanics).

METHODS AND RESULTS

Differences were found in baseline characteristics among the three groups including (1) age (mean age for whites, 57.2 years; blacks, 54.8 years; Hispanics, 52.8 years; P < .001), (2) sex (percentage of women for whites, 17.6; blacks, 28.7; Hispanics, 14.3; P < .001), and (3) risk factor prevalence: current smoking (percent for whites, 49.4; blacks, 62.1; Hispanics, 55.1; P < .003), history of hypertension (percent for whites, 36.6; blacks, 55.7; Hispanics, 39.5; P < .001), and diabetes mellitus (percent for whites, 11.9; blacks, 22.4; Hispanics, 19.7; P < .001). Changes in hemostatic factors 5 hours after infusion of recombinant tissue plasminogen activator (rt-PA) revealed a more profound fall in fibrinogen levels in black patients compared with the response seen in Hispanic or white patients (mean change in fibrinogen +/- SD, mg/dL: 151.3 +/- 107.4, 112.2 +/- 97.0, 109.4 +/- 98.6; P < .001, respectively) without more frequent infarct-related artery patency or hemorrhagic complications. Mortality was similar in the white, black, and Hispanic patients through the first year after adjustment for baseline variables.

CONCLUSIONS

TIMI II data yield evidence that (1) corroborates published reports of a high prevalence of classic cardiovascular risk factors among minority patients with acute myocardial infarction, (2) there is a greater decrease in fibrinogen levels 5 hours after the start of rt-PA infusion among black patients than in white and Hispanic patients without evidence of more frequent infarct-related artery patency or hemorrhagic complications, and (3) thrombolytic therapy with appropriate supplemental measures is associated with comparable 1-year mortality in white, black, and Hispanic patients.

Descriptions and depictions of environments

Subjects studied maps with the expectation that they would draw or describe them from memory. In fact, subjects did both. Order of drawing or describing landmarks revealed the mental organization of environments. Organization was quite similar across maps and descriptions of the same environments, revealing hierarchical structures based on spatial and functional features of the environments and on conventions for sequencing the landmarks.

Cytogenetic, biochemical, and molecular analyses of a 22q13 deletion

We report on a 3-year-old boy with a terminal deletion of 22q. The activity of alpha-N-acetylgalactosaminidase was normal while arylsulfatase A activity was reduced. Molecular analysis demonstrated the lack of paternal alleles of D22S45 and D22S55.

Deletion mapping of plasminogen activator inhibitor, type I (PLANH1) and beta-glucuronidase (GUSB) in 7q21----q22

DNA from a male fetus with an interstitial deletion of 7q22 [(46,XY,del(7)(pter----q22.10::q31.10----qter)] was analyzed using probes in this region of 7q. The results localize plasminogen activator inhibitor type I (PLANH1) to 7q22.1----q22.3 and beta-glucuronidase to band 7q21.11.