Biomedical subjects

B Applegate

Publications and source records attributed to B Applegate.

At least 19 recordsLinked to original sources

PubMed2001

Whole-cell biocomputing.

The ability to manipulate systems on the molecular scale naturally leads to speculation about the rational design of molecular-scale machines. Cells might be the ultimate molecular-scale machines and our ability to engineer them is relatively advanced when compared with our ability to control the synthesis and direct the assembly of man-made materials. Indeed, engineered whole cells deployed in biosensors can be considered one of the practical successes of molecular-scale devices. However, these devices explore only a small portion of cellular functionality. Individual cells or self-organized groups of cells perform extremely complex functions that include sensing, communication, navigation, cooperation and even fabrication of synthetic nanoscopic materials. In natural systems, these capabilities are controlled by complex genetic regulatory circuits, which are only partially understood and not readily accessible for use in engineered systems. Here, we focus on efforts to mimic the functionality of man-made information-processing systems within whole cells.

Computational Biology↗

PubMed2001

Validity of DSM-IV ADHD.

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Attention Deficit Disorder with Hyperactivity↗

PubMed2001

Rates and odds ratios for complications in closed and open tibial fractures treated with unreamed, small diameter tibial nails: a multicenter analysis of 467 cases.

OBJECTIVE: A multicenter trial analyzed complications and odds for complications in open and closed tibial fractures stabilized by small diameter nails. DESIGN: Retrospective. SETTING: Four Level I trauma centers. PATIENTS: Four hundred sixty-seven tibial fractures were included in the study. There were fifty-two proximal fractures, 219 midshaft fractures, and 196 distal fractures. Breakdown into different AO/OTA groups showed 135 Type A fractures, 216 Type B fractures, and 116 Type C fractures. Two hundred sixty-five were closed fractures and 202 were open fractures. OUTCOME MEASUREMENTS: Clinical and radiographic analysis. METHODS: 467 patients' tibial fractures were stabilized with small diameter tibial nails using an unreamed technique. Indications for the use of small diameter tibial nails using an unreamed technique included all types of open or closed diaphyseal fractures. The operating surgeons decided whether or not to ream based on personal experience, fracture type, and soft-tissue damage. Surgeons of Center 1 preferred to treat AO Type A and B fractures with unreamed nails, and surgeons of Centers 2, 3, and 4 preferred to treat AO Type B and C fractures with unreamed nails. Closed and open fractures were treated in approximately the same ratio. RESULTS: Analysis showed five (1.1 percent) deep infections (with a 5.4 percent rate of deep infections in Gustilo Grade III open fractures), forty-three delayed unions (9.2 percent), and twelve (2.6 percent) nonunions. Compartment syndromes occurred in sixty-two cases (13.3 percent), screw fatigue in forty-seven cases (10 percent), and fatigue failure of the tibial nail in three cases (0.6 percent). CONCLUSIONS: Fracture distraction of more than three millimeters should not be tolerated when stabilizing tibial fractures with unreamed, small-diameter nails as this increases the odds of having a delayed union by twelve times (p < 0.001) and a nonunion by four times (p = 0.057). There was a significant increase of complications in the group of Grade III open fractures (p < 0.001), AO/OTA Type C fractures (p = 0.002), and to a lesser extent in distal fractures. However, the rate of severe complications resulting in major morbidity was low.

Bone Nails↗

PubMed2001

Treatment of severely comminuted intra-articular fractures of the distal end of the radius by open reduction and combined internal and external fixation.

BACKGROUND: Severely comminuted AO type-C3 intra-articular fractures of the distal end of the radius are difficult to treat. Failure to achieve and maintain nearly anatomic restoration can result in pain, instability, and poor function. We report the results of a retrospective study of the use of a standard protocol of open reduction and combined internal and external fixation of these fractures. METHODS: Seventeen of twenty-five patients treated with the protocol were available for follow-up evaluation. Six had an AO type-C3.1 fracture; eight, type-C3.2; and three, type-C3.3. Eleven fractures required a dorsal buttress plate and/or a volar buttress plate, and eleven required bone-grafting. The mean time until the external fixator was removed was seven weeks. RESULTS: At a mean of thirty months postoperatively, the mean arc of flexion-extension was 72% of that on the uninjured side and the mean grip strength was 73% of that on the uninjured side. The mean articular step-off was 1 mm, the total articular incongruity (the gap plus the step-off) averaged 2 mm, and the radial length was restored to a mean of 11 mm. Thirteen patients had less than 3 mm of total articular incongruity. Arthritis was graded as none in three patients, mild in ten, moderate in three, and severe in one. According to the Gartland and Werley demerit-point system, ten of the patients had a good or excellent result. According to the modified Green and O'Brien clinical rating system, five had a good or excellent result. One patient had a fracture collapse requiring wrist fusion, one had reflex sympathetic dystrophy, and three had minor Kirschner-wire-related problems. Total articular incongruity immediately postoperatively had a moderately strong correlation with the outcome as assessed with both clinical rating systems (r = 0.70 and 0.74 for the Gartland and Werley system and the Green and O'Brien system, respectively; p<0.05). CONCLUSIONS: Open reduction and combined internal and external fixation of AO type-C3 fractures can restore radiographic parameters to nearly normal values, maintain reduction throughout the period of fracture-healing, and provide satisfactory functional results.

Adult↗

PubMed1999

Relation of age of onset to the type and severity of child and adolescent conduct problems.

In a cross-sectional household sample of 9-through 17-year-old youths from 4 U.S. communities, youths with earlier ages of onset of conduct problems engaged in more conduct problems than youths with later ages of onset when current age and gender were controlled. Specifically, youths with earlier ages of onset were more likely to engage in several types of physical aggression, frequent lying, theft, and vandalism and were less likely to engage in only truancy. There also was an inverse relation between age of onset and level of functional impairment, mental health service use, and meeting diagnostic criteria for conduct disorder, attention-deficit hyperactivity disorder, and oppositional defiant disorder. Within the limits of cross-sectional data, these results support the hypothesis that key aspects of the heterogeneity of conduct problems among youths are related to the age of onset of conduct problems.

Adolescent↗

PubMed1998

Validity of DSM-IV subtypes of conduct disorder based on age of onset.

OBJECTIVE: To present data from the DSM-IV field trials that led to the distinction between subtypes of conduct disorder (CD) that emerge in childhood or adolescence. In addition, data from a household sample were used to attempt to cross-validate these findings. METHOD: Differences between youths who met criteria for the two subtypes of CD were examined in the field trials sample of 440 youths aged 4 through 17 years and in a household sample of 1,285 youths aged 9 through 17 years. RESULTS: In both samples, there was a steep decline in aggression occurring around an age of onset of 10 years, but the number of nonaggressive behaviors was unrelated to the age of onset of CD. In the field trials sample, youths who met criteria for the adolescent-onset type were more likely to be girls, less likely to meet criteria for oppositional defiant disorder, and less likely to have a family history of antisocial behavior than the childhood-onset type, but these latter findings were not confirmed in the household sample. CONCLUSIONS: The DSM-IV approach to subtyping CD distinguishes subgroups that differ markedly in level of physical aggression. The advantages of a developmental approach to subtyping are discussed.

Adolescent↗

PubMed1997

Pseudomonas putida B2: a tod-lux bioluminescent reporter for toluene and trichloroethylene co-metabolism.

A tod-lux transcriptional fusion bioluminescent reporter strain, Pseudomonas putida B2, was developed to permit on-line analysis of trichloroethylene (TCE) transformation by toluene dioxygenase (todC1C2BA) in Pseudomonas putida F1. Strain B2 was exposed to toluene in growing and resting cell bioluminescence assays. The growing cells showed a direct correlation between bioluminescence and toluene concentration, while resting cells showed reproducible bioluminescence with repeated toluene exposures. In addition, P. putida B2 was encapsulated in alginate beads and used in a packed bed flow-through differential volume reactor. The TCE feed into the differential volume reactor was constant at 20 mg L-1 and toluene was pulsed in square-wave perturbations at 10 mg L-1. The system showed a direct correlation between the expression of the tod operon (as monitored by light output) and the co-metabolism of TCE. Approximately 20% of the TCE and 50% of the toluene was removed at a flow rate of 0.4 ml min-1. This approach allowed the on-line monitoring of tod gene expression and its relation to TCE biotransformation.

Alginates↗

PubMed1997

Validity of the age-of-onset criterion for ADHD: a report from the DSM-IV field trials.

OBJECTIVE: To examine the validity of the DSM-IV requirement of an age of onset of impairment due to symptoms before 7 years of age for the diagnosis of attention-deficit/hyperactivity disorder (ADHD). METHOD: The validity of this criterion was examined in a clinic sample of 380 youths aged 4 through 17 years by comparing youths who met symptom criteria for ADHD and either did or did not display impairment before age 7 years. RESULTS: Nearly all youths who met symptom criteria for the predominantly hyperactive-impulsive subtype also met the age of onset of impairment criterion, but 18% of youths who met symptom criteria for the combined type, and 43% of youths who met symptom criteria for the predominantly inattentive type, did not manifest impairment before 7 years. For the latter two subtypes, requiring impairment before age 7 years reduced the accuracy of identification of currently impaired cases of ADHD and reduced agreement with clinicians' judgments. CONCLUSIONS: These findings raise questions about the validity of the DSM-IV definition of age of onset of ADHD. Marked differences in the ages of onset of both symptoms and impairment for the three subtypes of ADHD support the validity of distinguishing among these subtypes in DSM-IV.

Adolescent↗

PubMed1996

Lower extremity blood flow and responses to occlusion ischemia differ in exercise-trained and sedentary tetraplegic persons.

OBJECTIVE: To test whether lower extremity blood flow and hyperemic responses to vascular occlusion differ among electrically stimulated exercise trained and sedentary tetraplegic persons and subjects without tetraplegia (control). DESIGN: Blinded cross-sectional comparison, control group. SETTING: Academic medical center. PARTICIPANTS: Ten sedentary tetraplegic men, 10 tetraplegic persons previously habituated to electrically stimulated cycling exercise for 0.4 to 7 years, and 10 nondisabled controls. OUTCOME MEASURES: Subjects underwent quantitative Doppler ultrasound examination of the common femoral artery (CFA). End-diastolic arterial images and arterial flow-velocity profiles obtained at rest and following five minutes of suprasystolic thigh occlusion were computer digitized for analysis of heart rate (HR), CFA peak systolic velocity (PSV), CFA cross-sectional area (CSA), flow velocity integral (FVI), and computed CFA inflow volume (IV). RESULTS: No group main effects were observed for resting HR or FVI. At rest, trained tetraplegic men had 14.9% greater PSV, 29.8% larger CSA, and 51.3% greater IV (p values < .05) than sedentary tetraplegic subjects. Resting PSV and IV of the trained subjects did not differ from controls, although CSA was smaller than controls (p < .05). Following occlusion, PSV, CSA, and IV averaged 16.5%, 33.4%, and 65.1% greater for trained tetraplegics persons, respectively, than sedentary tetraplegic subjects (p values < .05). Only CSA differed between the control and the trained groups (p < .05). CONCLUSION: Tetraplegic persons conditioned by electrically stimulated cycling have greater lower extremity blood flow and hyperemic responses to occlusion than do their sedentary counterparts.

Adult↗

PubMed1996

His and her individualisms? Sex bias and individualism in psychologists' responses to case vignettes.

Individualism and sexism have been identified as important and problematic biases in psychotherapy. The extent to which psychologists use individualist values differentially in their responses to clinical case vignettes describing men and women was examined. Two samples of practicing psychologists (N=229) responded to 14 clinical vignettes by choosing initial hypotheses about the client that reflected either a utilitarian, instrumental (traditionally masculine) perspective or expressive (traditionally feminine) themes. Two sex-of-client manipulations were conducted, one of which resulted in a sex-of-client effect. A loglinear logit analysis of repeated measures conducted with the non-manipulated vignettes indicated a marked preference for the utilitarian form of individualism for males in response to their clinical difficulties, whereas the responses for female clients were more balanced on the utilitarian and expressive alternatives. There was little evidence of a sex-of-respondent effect.

Adult↗

PubMed1996

Twenty-one-month follow-up study of school-age children exposed to Hurricane Andrew.

OBJECTIVE: To explore the 21-month course of posttraumatic stress symptomatology (PTSS) and psychological morbidity in 30 school-age children (7 to 13 years) after exposure to Hurricane Andrew. METHOD: Pynoos' Posttraumatic Stress Disorder Reaction Index and Achenbach's Teacher's Report Form were administered at 8 and 21 months after Hurricane Andrew. RESULTS: At 21 months 70% of the children endorsed moderate-severe PTSS. The reduction in PTSS was greater for boys than girls. Psychopathology as measured by the Teacher's Report Form increased over the 19-month period. Boys demonstrated significant increases in internalizing symptoms and in Withdrawn, Anxious/Depressed, Social Problems, and Attention Problems scales, and girls showed a significant increase in the Anxious/Depressed scale. CONCLUSIONS: Twenty-one months after exposure to Hurricane Andrew, there were continuing high levels of PTSS and evidence of increasing emotional and behavioral problems. While girls sustained higher levels of PTSS, boys demonstrated higher indices of other psychopathology. The enduring effects of disaster associated with secondary stressors and "traumatic reminders" continue to be etiologically important for continuing psychological morbidity.

Adolescent↗

PubMed1996

Nutrient intake and psychological and physiological assessment in eumenorrheic and amenorrheic female athletes: a preliminary study.

The present study showed that amenorrheic athletes (AAs) scored higher on the Eating Attitudes Test (EAT) (p < .05) than eumenorrheic athletes (EAs), indicating more aberrant eating patterns in the first group. Scores on the EAT were inversely correlated with fat intake (p < .05), simple carbohydrate intake (p < .01), and percentage saturation of iron (p < .05) and were positively correlated with total iron binding capacity (p < .01) for the total sample. Physiological assessment of athletes revealed that there were no significant differences between groups in serum lipoproteins, with both EAs and AAs having serum lipid profiles indicative of low cardiovascular risk. Furthermore, low-density lipoprotein cholesterol was the only lipoprotein significantly and positively correlated with serum estradiol levels for the entire sample (p = .01). The present study was in agreement with previous work showing that scores of the EAT represent a primary difference between EAs and AAs; the present study was somewhat different than previous work in that serum lipoproteins were not significantly related to menstrual status.

Adult↗

PubMed1995

Developmental change in attention-deficit hyperactivity disorder in boys: a four-year longitudinal study.

One hundred six clinic-referred boys meeting criteria for DSM-III-R attention-deficit hyperactivity disorder (ADHD) (mean age 9.4 years) were assessed annually for 4 years using structured interviews of multiple informants. Hyperactivity-impulsivity symptoms declined with increasing age, but inattention symptoms did not. Rather, inattention declined only from the first to the second assessment and remained stable thereafter in boys of all ages. The rate of decline in hyperactivity-impulsivity symptoms was independent of the amount and type of treatment received. Boys who still met criteria for ADHD in Years 3 and 4 were significantly younger, more hyperactive-impulsive, and more likely to exhibit conduct disorder in Year 1 than boys who no longer met criteria in Years 3 and 4.

Age Factors↗

PubMed1995

Effects of electrically-stimulated exercise and passive motion on echocardiographically-derived wall motion and cardiodynamic function in tetraplegic persons.

The purposes of the study were (1) to characterize left ventricular wall motion, and the cardiodynamic and metabolic responses during electrical stimulation cycle ergometry (ESCE) exercise in tetraplegic people; (2) to test whether these responses linger into the post-exercise recovery period; and (3) to test whether they differ from those imposed by lower extremity continuous passive motion (CPM). Subjects were six tetraplegic males aged 25.8 +/- 3.1 (mean +/- SD) years with spinal cord injuries of 6.7 +/- 3.5 years' duration at the C5 and C6 levels (Frankel classifications A and B). On randomized non-consecutive days, subjects underwent either 30 min of steady-state exercise using transcutaneous electrically-stimulated contractions of bilateral quadriceps, hamstring, and gluteus muscle groups, or 30 min of continuous passive motion at 50 rpm. Data were taken at rest, min 15 and 30 of treatment, and min 5, 15, and 30 post-treatment. Stroke volume (SV) was measured echocardiographically as the product of the left ventricular outflow tract area and the integrated area under the left ventricular outflow tract flow-velocity curve acquired by doppler ultrasound. This value was multiplied by heart rate (HR) to determine the cardiac output (CO). Oxygen consumption (VO2) was monitored spirometrically, with arteriovenous oxygen difference (a-vO2DIFF) computed algebraically. Data were analyzed using repeated measures within-subjects design anaysis of variance, with significance accepted at the 0.05 level. Results showed five subjects had small hyperkinetic ventricles at rest that became more dynamic during ESCE than CPM. Though no systolic dysfunction was noted, all but one subject exhibited some degree of septal hypokinesis at rest and during exercise, possibly indicative of left ventricular noncompliance. Significant effects of condition (ESCE vs CPM), trial (measurement time point), and their interaction, were observed for CO (P < 0.05, 0.01, and 0.0001, respectively), HR (P < 0.0001, 0.05 and 0.005, respectively), and VO2 (P < 0.001, 0.05 and 0.005, respectively). A significant trial and condition by trial interaction was found for a-vO2DIFF (P < 0.05 and 0.0001, respectively). No effects for condition, trial or their interaction were found for SV or BPDIAS. Electrical stimulation cycle ergometry-treated subjects achieved peak VO2 of 712 +/- 300 ml min-1, 2.63 times baseline, with 56% elevation of a-vO2DIFF. Cardiac output increased from 3.5 +/- 1.51 min-1 to 6.0 +/- 2.11 min-1, an elevation solely attributable to a 57% increase in HR. Thus, both CO and a-vO2DIFF accounted for elevated VO2 during ESCE.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1995

Psychological effects of Hurricane Andrew on an elementary school population.

OBJECTIVE: To explore the prevalence and progression of posttraumatic symptomatology (PTS), using emotional and behavioral indices of psychopathology in school-age children in the pathway of Hurricane Andrew (HI-IMPACT) and in a comparison group north of Miami (LO-IMPACT). METHOD: Pynoos' Posttraumatic Stress Disorder Reaction Index and Achenbach's Teacher's Report Form (TRF) were administered 8 weeks and 32 weeks after the hurricane. In addition, 21 measures of disruptive behavior cataloged by Dade County Public Schools were aggregated and compared by grading period between pre- and posthurricane school years. RESULTS: There were no statistically significant differences between the two schools in PTS at 8 weeks after the hurricane, although the children in the HI-IMPACT school were more likely to have severe PTS. TRF findings at 8 weeks revealed that children in the HI-IMPACT school evidenced lower means on the eight TRF scales and on the broader Internalizing and Externalizing measures. Analysis of the disruptive behavior revealed a drop in the marking period immediately after the hurricane in the HI-IMPACT area, but an opposite effect was observed in the LO-IMPACT area. CONCLUSIONS: After the hurricane there was an initial increase in PTS and a concomitant decrease in other measures of behavior and psychopathology. PTS remained relatively high throughout the school year, but there was a rebound and subsequent normalization of the measures of disruptive behavior.

Child↗

PubMed1994

DSM-IV field trials for the disruptive behavior disorders: symptom utility estimates.

OBJECTIVE: We tested the predictive utility of symptoms for proposed DSM-IV definitions of the disruptive behavior disorders using indices corrected for symptom and diagnosis base rates. METHOD: The field trials sample consisted of 440 clinic-referred youths who were consecutive referrals to a heterogeneous group of mental health clinics. Multiple informants were interviewed to determine the presence of symptoms and diagnoses. RESULTS: Some symptoms which were either not in DSM-III or DSM-III-R, or were modifications of DSM-III-R symptoms, had greater diagnostic efficiency than did several existing symptoms. Symptom utility estimates were generally similar for different ages and genders, although some interesting age and sex trends emerged for a few symptoms. CONCLUSIONS: The results supported the inclusion of more restricted definitions of "lying" and "truancy" to increase their association with a conduct disorder diagnosis and they supported the elimination of "swearing" in the oppositional defiant disorder criteria. In addition to their relevance for developing optimal criteria for DSM-IV, these results can aid DSM-IV users by providing a useful guide to the relative efficiency of individual symptoms based on data from a large heterogeneous clinic population.

Adolescent↗

PubMed1994

DSM-IV field trials for attention deficit hyperactivity disorder in children and adolescents.

OBJECTIVE: Optimal diagnostic thresholds were determined for DSM-IV attention deficit hyperactivity disorder, and the psychometric properties were compared to alternative definitions. METHOD: Structured diagnostic interviews of multiple informants for 380 clinic-referred youths aged 4-17 years were conducted. In addition, standardized clinicians' validation diagnoses of attention deficit disorder were obtained to assess agreement with clinical judgment. Measures of impairment were obtained to assess the accuracy of identifying youth with an impairing condition. RESULTS: Three subtypes of attention deficit hyperactivity disorder (predominantly inattentive, predominantly hyperactive-impulsive, and combined types) were distinguished on the basis of the degree of deviance on separate dimensions of inattention and hyperactivity-impulsivity. These three subtypes were found to differ in terms of types of impairment, age, and sex ratio, but not ethnicity. In terms of case identification of attention deficit hyperactivity disorder, DSM-IV was found to be very similar to DSM-III-R, except that DSM-IV identified more impaired girls and preschool children. CONCLUSIONS: These results support the decision to subdivide the heterogeneous category of DSM-III-R attention deficit hyperactivity disorder into three subtypes. The resulting DSM-IV definition appears to be somewhat less biased toward the symptom pattern typical of elementary school boys.

Adolescent↗

PubMed1994

DSM-IV field trials for oppositional defiant disorder and conduct disorder in children and adolescents.

OBJECTIVE: The purpose of the field trials for oppositional defiant disorder and conduct disorder was to select valid diagnostic thresholds for these disorders and to compare the psychometric properties of DSM-IV criteria for oppositional defiant disorder and conduct disorder with previous DSM diagnostic formulations. METHOD: Structured diagnostic interviews, standardized clinician's validation diagnoses, and multiple measures of impairment were obtained for 440 clinic-referred children and adolescents aged 4-17 years. RESULTS: A diagnostic threshold of four symptoms of oppositional defiant disorder optimized identification of impaired children, improved agreement somewhat with the clinician's validation diagnosis, and had somewhat better test-retest agreement than DSM-III-R. In the case of conduct disorder, the optimal time window for ascertainment of symptoms was clarified. A diagnostic threshold of three symptoms of conduct disorder maximized accurate identification of impaired children and agreement with the clinician's validation diagnosis and resulted in slightly better test-retest agreement than DSM-III-R. Compared with the DSM-III-R definition, the DSM-IV definition of oppositional defiant disorder was somewhat more prevalent, but the prevalence of conduct disorder was essentially unchanged. CONCLUSIONS: DSM-IV definitions of oppositional defiant disorder and conduct disorder are somewhat better than DSM-III-R definitions in terms of internal consistency and test-retest agreement, and the validity of the DSM-IV definition of oppositional defiant disorder is slightly better than that of DSM-III-R.

Adolescent↗