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Biomedical subjects

R J Sullivan

Publications and source records attributed to R J Sullivan.

At least 37 records · Page 2Linked to original sources
PubMed1999

Diagnosing aneurysmal and unicameral bone cysts with magnetic resonance imaging.

The differential between aneurysmal bone cysts and unicameral bone cysts usually is clear clinically and radiographically. Occasionally there are cases in which the diagnosis is not clear. Because natural history and treatment are different, the ability to distinguish between these two entities before surgery is important. The authors reviewed, in a blinded fashion, the preoperative magnetic resonance images to investigate criteria that could be used to differentiate between the two lesions. All patients had operative or pathologic confirmation of an aneurysmal bone cyst or unicameral bone cyst. The authors analyzed the preoperative magnetic resonance images of 14 patients with diagnostically difficult bone cysts (eight children with unicameral bone cysts and six children with aneurysmal bone cysts) and correlated these findings with diagnosis after biopsy or cyst aspiration and contrast injection. The presence of a double density fluid level within the lesion strongly indicated that the lesion was an aneurysmal bone cyst, rather than a unicameral bone cyst. Other criteria that suggested the lesion was an aneurysmal bone cyst were the presence of septations within the lesion and signal characteristics of low intensity on T1 images and high intensity on T2 images. The authors identified a way of helping to differentiate between aneurysmal bone cysts and unicameral bone cysts on magnetic resonance images. Double density fluid level, septation, and low signal on T1 images and high signal on T2 images strongly suggest the bone cyst in question is an aneurysmal bone cyst, rather than a unicameral bone cyst. This may be helpful before surgery for the child who has a cystic lesion for which radiographic features do not allow a clear differentiation of unicameral bone cyst from aneurysmal bone cyst.

Adolescent↗
PubMed1999

Social deficits associated with schizophrenia defined in terms of interpersonal Machiavellianism.

The social deficits of schizophrenia have been interpreted in an evolutionary context of Machiavellian social dexterity, stressing deficits in evolved psychological mechanisms that mediate the interpretation of affect and deceptive intention in others. A complementary hypothesis was tested, that patients with schizophrenia will be relatively non-Machiavellian compared to controls, and that social problems associated with the condition may reflect this relative social credulity. This hypothesis was addressed by assessing Mach IV psychometric scale performance in a group of 51 patients with schizophrenia and in 93 controls. Males, but not females, with schizophrenia scored significantly lower on the Mach IV scale than control groups. This result is interpreted in conjunction with the existing literature on social competence and sex differences in the symptomatology of patients with schizophrenia.

Adolescent↗
PubMed1999

How many nights are enough? The short-term stability of sleep parameters in elderly insomniacs and normal sleepers.

Temporal stability is an important fundamental quality when measuring sleep parameters, yet it has been infrequently assessed. Generalizability theory was used to estimate the short-term temporal stability of five variables commonly used to characterize insomnia: sleep onset latency, total sleep time, wake after sleep onset, time in bed, and sleep efficiency. Estimates were calculated for 32 elderly primary insomniacs and 32 elderly normal sleepers, both in the lab and at home, using both sleep logs and polysomnography (PSG). A week of recording using either PSG or sleep logs was typically sufficient to achieve adequate stability (defined as G coefficient of at least 0.80) with some notable exceptions: (a) when using log-derived measures with insomniacs, a 3-week average was necessary for wake after sleep onset and (b) more than a 2-week average was necessary for sleep onset latency. Because of the substantial commitment involved in the physiological recording of sleep, alternative forms of aggregation are considered with the intent of improving temporal stability.

Aged↗
PubMed1999

Patient factors related to the odds of receiving prevention services in Veterans Health Administration medical centers.

OBJECTIVE: To examine the association between patient characteristics and the odds of receiving 13 health promotion/disease prevention services recommended by the US Preventive Services Task Force (USPSTF) for average-risk individuals. METHODS: A mail survey was sent to a random sample of 68,422 veterans who obtained primary care from any of the 153 Veterans Health Administration facilities in 1996; 44,304 responded (adjusted response rate was 68%). Multivariate logistic regression models were used. RESULTS: Demographic factors, health risk behaviors, and self-reported health were associated with the odds of receiving prevention services. Current smokers, heavy alcohol drinkers, and females were less likely to receive many health promotion services, whereas regular exercisers, overweight individuals, males, those reporting poorer health, individuals reporting high or controlled blood pressure, and those reporting high or controlled cholesterol levels were more likely to receive USPSTF-recommended prevention services. CONCLUSION: Substantial proportions of veterans were likely to obtain prevention services recommended by the USPSTF for average-risk individuals. Nevertheless, veterans who reported being current smokers, heavy drinkers, or female were less likely to obtain these services. These subgroups may benefit from additional initiatives.

Adult↗
PubMed1998

Geological evidence for solid-state convection in Europa's ice shell.

The ice-rich surface of the jovian satellite Europa is sparsely cratered, suggesting that this moon might be geologically active today. Moreover, models of the satellite's interior indicate that tidal interactions with Jupiter might produce enough heat to maintain a subsurface liquid water layer. But the mechanisms of interior heat loss and resurfacing are currently unclear, as is the question of whether Europa has (or had at one time) a liquid water ocean. Here we report on the morphology and geological interpretation of distinct surface features-pits, domes and spots-discovered in high-resolution images of Europa obtained by the Galileo spacecraft. The features are interpreted as the surface manifestation of diapirs, relatively warm localized ice masses that have risen buoyantly through the subsurface. We find that the formation of the features can be explained by thermally induced solid-state convection within an ice shell, possibly overlying a liquid water layer. Our results are consistent with the possibility that Europa has a liquid water ocean beneath a surface layer of ice, but further tests and observations are needed to demonstrate this conclusively.

Extraterrestrial Environment↗
PubMed1998

Effect of acetabular component orientation on recurrent dislocation, pelvic osteolysis, polyethylene wear, and component migration.

We retrospectively reviewed 75 total hip arthroplasties to examine the effect of acetabular component position. In group A, 38 of the components were implanted according to manufacture's instructions with all peripheral fins in contact with acetabular bone; as such, the acetabular components were in a relatively vertical position with a mean angle of inclination of 61.9 degrees. Three of these patients developed recurrent dislocations necessitating revision of the acetabular component. In group B, 37 hips, a more horizontal orientation was used despite the fact that all of the peripheral fins of the acetabular component did not engage acetabular bone; in this group the mean angle of inclination was 49.7 degrees. Only one of these hips recurrently dislocated and required revision. There were no problems in this group associated with provisional component stability caused by inadequate peripheral fixation. Radiographs of all patients were obtained at 4 years after surgery (range, 4.0-4.3 years). Pelvic osteolysis had occurred in 24% of hips in group A and 13% of group B. Asymmetric polyethylene wear was observed in 5.1% of the hips in group A; no hip in group B showed wear asymmetry. Acetabular component migration developed in 19% of group A hips and 5% of group B hips. The Mayo clinical hip score was excellent in both groups: group A 71/80, group B 73/80. At an intermediate follow-up it is clear that significant problems can be encountered when this component is positioned in a relatively vertical position to facilitate engaging all four peripheral fins in bone. We have addressed this problem by placing the cup in a more anatomic position of inclination while maintaining provisional rim fixation. This has resulted in a decreased incidence of pelvic osteolysis and fewer complications overall.

Aged↗
PubMed1997

Sleep in the laboratory and sleep at home: comparisons of older insomniacs and normal sleepers.

Many laboratory polysomnographic (LPSG) studies have shown only modest sleep differences between insomniacs and matched, noncomplaining normal controls. However, the extent to which LPSG methodology affects the outcome of such comparisons has yet to be tested. In the current investigation, 32 (16 females, 16 males) older (age > or = 60 years) insomniacs and an age-matched and gender-matched sample of 32 noncomplaining normal sleepers underwent three consecutive nights of LPSG monitoring and another three consecutive nights of PSG monitoring in their homes (HPSG). By random assignment, one-half of the subjects in each group underwent LPSG first, whereas the remaining subjects underwent HPSG first. Each PSG recording was blindly scored using conventional scoring criteria, and resulting measures of total sleep period, total sleep time, sleep efficiency percent, stage 1 time, slow-wave sleep time, and rapid eye movement latency were used to compare the two subject groups within each PSG recording site (i.e. lab and home). Statistical analyses showed the normals sleepers and insomniacs evidenced similar pronounced first night effects (FNEs) when undergoing LPSG. However, neither mean values of the selected sleep parameters nor measures reflecting their night-to-night variability differentiated the insomniacs from the normal sleepers when such measures were derived from LPSG. In contrast, FNEs were generally absent for both subject groups when they underwent HPSG. Moreover, the insomniacs displayed significantly greater variability in several of their sleep measures during HPSG than did the normal sleepers. Overall, results suggest FNEs are a concern mainly when using LPSG, and HPSG may be more sensitive than LPSG for documenting sleep differences between normal sleepers and insomniacs. Additional studies are needed to determine if the findings reported herein are similar for young and middle-aged adults.

Aged↗
PubMed1997

In vivo detection of calcium from dicalcium phosphate dihydrate dentifrices in demineralized human enamel and plaque.

A series of studies was conducted to clarify the role of DCPD in improving the effects of fluoride in the mouth. We performed plaque fluid studies to see if the use of DCPD dentifrices increases the levels of free Ca2+ ions and the DSenamel in plaque fluid. The results of these studies showed that plaque fluid was undersaturated with respect to DCPD; therefore, DCPD would dissolve in the mouth. The Ca2+ activity in plaque fluid measured 12 hours post-treatment was significantly elevated with the use of DCPD dentifrices in comparison with silica dentifrices. The use of DCPD dentifrices also increased the DSenamel of plaque fluid in comparison with a NaF/silica dentifrice. To determine whether Ca from DCPD could be detected in demineralized enamel and whole plaque after in vivo usage of a DCPD/ fluoride dentifrice, we conducted a 44Ca labeling study. Secondary Ion Mass Spectrometry (SIMS) was used to detect and measure changes in 44Ca levels in enamel before and after 6 days of in vivo treatment with a 44DCPD/fluoride dentifrice. The results showed that 44Ca from DCPD was incorporated into enamel and detected in plaque 18 hours post-treatment. The findings from these studies show that brushing with a DCPD dentifrice introduces additional, exogenous Ca into the oral environment, which fosters improved remineralization of teeth in combination with fluoride.

Calcium↗
PubMed1997

Do our methods lead to insomniacs' madness?: Daytime testing after laboratory and home-based polysomnographic studies.

Complaints of daytime dysfunction are common among chronic insomniacs, but laboratory comparisons of insomniacs and age-matched and gender-matched normal controls have generally failed to document these complaints. However, a few studies, which allowed subjects to sleep in their homes on the nights before daytime testing, have shown some relative diurnal deficits among insomniacs. The current study compared the effects of nocturnal laboratory and home polysomnogram (PSG) studies on subsequent daytime test results among older insomniacs and normal sleepers. Insomniacs (n = 32) and normal sleepers (n = 32) were randomly assigned to first undergo three nights of nocturnal PSG monitoring either in the sleep laboratory (16 insomniacs, 16 normal sleepers) or in their homes (16 insomniacs, 16 normal sleepers). Following the third night of PSG monitoring, subjects spent 1 day in the sleep laboratory, where they completed a four-trial multiple sleep latency test along with four trials of a computer-administered performance test battery. Results showed that insomniacs, as a group, were slightly, albeit consistently, sleepier than were normal sleepers following nights of home sleep monitoring, but a reverse of this trend was found among subjects who underwent nocturnal laboratory PSG before daytime testing. Furthermore, normal sleepers showed faster reaction times on a signal detection task than did insomniacs within the subgroup who underwent home PSGs prior to such testing. However, within the subgroup that underwent nocturnal laboratory PSGs, insomniacs' signal detection reaction times were significantly faster than those shown by normal sleepers. Results provide some support for the speculation that the nocturnal PSG monitoring site, used as a precursor to daytime testing, may systematically affect daytime comparisons between insomniacs and matched controls. Moreover, these results suggest that the use of home-based nocturnal PSG monitoring prior to daytime testing may provide an enhanced understanding of insomniacs' diurnal complaints.

Aged↗
PubMed1996

Five-year performance trends for older exercisers: a hierarchical model of endurance, strength, and flexibility.

OBJECTIVE: To examine 5-year trends in measures of physical performance, and the impact of disease upon performance, in three domains: cardiovascular fitness, musculo-skeletal strength, and flexibility among older adults participating in a medically supervised exercise program. DESIGN: Longitudinal analyses of data obtained in an observational cohort study. SETTING: Department of Veterans Affairs Medical Center in Durham, North Carolina. PARTICIPANTS: Seventy-three community-dwelling veterans between 64 and 90 years of age. INTERVENTION: Voluntary participation in a medically supervised outpatient exercise program meeting 3 days per week for 90 minutes per session. MAIN OUTCOME MEASURES: Changes over time in cardiovascular fitness, musculoskeletal strength, and flexibility. RESULTS: Forty-nine percent of the original study participants remained in the program for a full 5 years. They had lower baseline rates of cardiorespiratory and musculoskeletal diseases than did the dropouts. Dropouts were significantly more impaired in baseline measures of cardiovascular fitness (P = .038) and strength (P = .007). Changes over time for cardiovascular fitness and strength were similar. Only linear (P < .05) and quadratic time (P < .001) were significant. Only linear time was significant for measures of flexibility (P < .05). Baseline cardiorespiratory disease, baseline musculoskeletal disease, and interaction terms were not significant. Overall, measures of physical performance demonstrated gradual improvement for 2 to 3 years, followed by a gradual decline in performance irrespective of baseline disease status. CONCLUSION: Older adults who exercise regularly, including those with multiple chronic diseases, can achieve significant gains in measures of physical performance, and these gains can be sustained for 2 to 3 years.

Aged↗
PubMed1996

Comparison of cognitive-behavioral therapy and clonazepam for treating periodic limb movement disorder.

Many patients with periodic limb movement disorder (PLMD) display inadequate sleep hygiene, and others decline conventional pharmacologic intervention for their form of sleep disturbance. Nonetheless, the use of nonpharmacologic therapies with PLMD remains unexplored. The current study was designed to compare the short-term treatment effects of a cognitive-behavioral therapy (CBT) and conventional pharmacotherapy (clonazepam) among a group of insomniacs with PLMD. The 16 subjects participating in this study first underwent baseline assessment procedures, including completion of a sleep log for 2 weeks, an ambulatory polysomnogram (APSG) and an Insomnia Symptom Questionnaire (ISQ). They then were randomized either to CBT (n = 8) or standard clonazepam therapy (n = 8). Subjects maintained sleep logs throughout a 4-week treatment and then completed a second APSG and ISQ. Comparison of pre- and post-treatment data suggested that the two treatments led to equal improvements in sleep log measures of sleep-wake times and ISQ measures of subjective sleep concerns. Patients treated with CBT showed a decrease in daytime napping, whereas the clonazepam group reported increased napping. Conversely, those treated with clonazepam showed larger declines in periodic limb movement-arousals per hour of sleep than did the CBT group. Post-treatment interviews suggested that both CBT and clonazepam therapies were generally well tolerated by study participants. It is concluded that both treatments may be useful for PLMD but that the two treatments may have contrasting effects across selected measures of improvement. Additional research is needed to examine the long-term efficacy of CBT as a primary or adjunctive treatment for varying levels of PLMD severity.

Aged↗
PubMed1995

Medication taking behaviors in the high- and low-functioning elderly: MacArthur field studies of successful aging.

OBJECTIVE: To describe and compare medication-taking behaviors in the high- and low-functioning elderly living in the community. DESIGN: A cross-sectional design with data collected by interview. SETTING: The study included 5 counties in the southern Piedmont area of North Carolina. PARTICIPANTS: Respondents included 242 elderly aged 70-79 years selected from the Piedmont Health Survey of the Elderly and the MacArthur Research Program on Successful Aging. MAIN OUTCOME MEASURES: Outcome measures included strategies used to remember to take drugs, reasons given for skipping medications, factors associated with understanding of drugs, the number of over-the-counter and prescribed drugs used, and the number of drugs used in therapeutic categories. RESULTS: Low-functioning elderly white respondents took greater numbers of prescribed drugs than did blacks or high-functioning whites. Respondents had a better understanding of prescribed than of over-the-counter drugs, with the poorest understanding of nutritional supplements. Men and blacks had poorer understanding of drugs than women and whites. The strategies subjects used to remember to take drugs included (from most to least frequently used): making it a routine activity, reading labels, a self-devised memory aid, a habit, being reminded by someone else, sorting, and noticing symptoms. CONCLUSIONS: Clinicians should provide their patients with information about over-the-counter agents as well as prescribed drugs, be alert to cues that blacks and men give indicating their need for additional explanation about a drug's purposes, and be sensitive to differential prescribing patterns with respect to race. When planning a regimen for multiple doses of a drug, clinicians should account for their patients' tendencies to use routine activities as memory prompts.

Black or African American↗
PubMed1995

Intra-oral comparison and evaluation of the ability of fluoride dentifrices to promote the remineralization of caries-like lesions in dentin and enamel.

The effect of three types of fluoride dentifrices and one non-fluoride dentifrice were evaluated and compared intra-orally for their ability to promote the remineralization of caries-like lesions in thin sections of human dentin and enamel. The three fluoride dentifrices were silica based. One dentifrice contained 0.76% sodium monofluorophosphate (MFP), another contained 0.247% sodium fluoride (NaF), and the third contained 0.247% NaF plus 1.3% pyrophosphate and 1.5% polyvinylmethyl ether/maleic acid (PVM/MA) copolymer (denoted NaF/PPi). The fourth dentifrice (placebo) was also silica based, but contained no fluoride, and served as a negative control. Two week treatment resulted in the following percent mineral changes for the enamel specimens: +21 +/- 16 for MFP, +10 +/- 30 for NaF, +16 +/- 15 for NaF/PPi, and -30 +/- 30 for the placebo. The respective percent mineral change values for the dentin specimens were +28 +/- 20 for MFP, +22 +/- 19 for NaF, +28 +/- 18 for NaF/PPi, and -34 +O/- 61 for the placebo. A statistical analysis revealed that the three fluoride dentifrices were significantly better (p<0.05) than the placebo at promoting remineralization for both types of specimens. No significant differences were found among the three fluoride dentifrices. The following can be concluded from this study: 1) silica based dentifrices containing MFP and NaF are effective at remineralizing caries-like lesions in both enamel and dentin; 2) there was no statistical difference between NaF and MFP in their ability to promote remineralization; and 3) pyrophosphate does not interfere with the remineralizing effects of NaF.

Analysis of Variance↗
PubMed1994

The Gerofit Program: a VA innovation.

In 1986 Gerofit, an exercise and health promotion program for older veterans, was established. This paper describes the program in detail by summarizing the patient assessment protocol, the exercise program, and program evaluation, as well as observational outcomes for up to 5 years of follow-up. Our data suggest that exercise provides older veterans with beneficial gains in function that are maintained for 5 years.

Aged↗
PubMed1993

A comparison of chest compressions between mechanical and manual CPR by monitoring end-tidal PCO2 during human cardiac arrest.

STUDY OBJECTIVE: To compare the use of mechanical and manual chest compressions during cardiac arrest based on continuous monitoring of end-tidal PCO2 (PETCO2). DESIGN: Prospective, randomized, crossover design. SETTING AND PARTICIPANTS: Fifteen consecutive adults ranging in age from 33 to 78 years who presented in nontraumatic cardiac arrest to the emergency department of a large teaching hospital. INTERVENTIONS: Study protocols were begun late in the resuscitation after initial resuscitation attempts were unsuccessful. Patients received four alternating five-minute trials (two manual and two mechanical), being randomized to begin with either technique. Mechanical compressions were performed by a mechanical device at a compression depth of 2 in. Both mechanical and manual compressions were delivered at a rate of 80 with a ventilation delivered after every fifth compression. Persons performing manual CPR were experienced American Heart Association basic life support providers, and no person performed manual CPR more than once during the study period. No resuscitative drugs were administered during the study period. PETCO2 was monitored continuously; those performing manual CPR were blinded to the PETCO2 monitor. Data were analyzed with repeated-measures analysis of variance and Scheffé multiple comparisons with the alpha error rate set of .05. MEASUREMENTS AND RESULTS: Mean PETCO2 during mechanical CPR was 13.6 +/- 4.14 mm Hg compared with 6.9 +/- 2.42 mm Hg during manually performed CPR (P < .001), a difference of 97%. Average mechanical CPR PETCO2 was higher in all cases. No patient was resuscitated successfully. Capnography also indicated that most CPR providers were inconsistent in their chest compressions. CONCLUSION: This study suggests that cardiac output produced with mechanical chest compressions is greater than that produced with manual compressions as demonstrated by the significantly higher PETCO2 levels during mechanical CPR. Reasons for this are unclear. In addition, monitoring of PETCO2 may help optimize chest compressions during CPR.

Adult↗
PubMed1993

Aerobic fitness, acute exercise and sleep in older men.

In the current study 12 aerobically fit and 12 sedentary older men underwent two nocturnal polysomnographic (PSG) studies. A control PSG was conducted following a day without aerobic activity, whereas a postexercise PSG study was conducted following an afternoon session of exhaustive aerobic exercise. In addition to deriving usual sleep parameters, a computer scoring program was used to count the number of individual electroencephalographic (EEG) slow waves in each PSG tracing. Multivariate and univariate analyses showed that the fit subjects had shorter sleep onset latencies, less wake time after onset, fewer discrete sleep episodes, fewer sleep stage shifts during the initial portion of the night, less stage 1 sleep, a higher sleep efficiency and more total slow waves during both PSGs than did the sedentary subjects. Although no main effects were found for the acute exercise challenge, post hoc analyses showed that high levels of body heating during exercise predicted increased sleep fragmentation for both fit and sedentary subjects. These findings provide initial support for the contention that exercise and fitness may have significant effects on the sleep of older men. However, results also suggest that high levels of body heating resulting from a single exercise challenge may have adverse effects. Implications of the study are discussed and suggestions for future research are provided.

Age Factors↗