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Biomedical subjects

T Fenton

Publications and source records attributed to T Fenton.

At least 19 recordsLinked to original sources
PubMed1992

Effects of diuretic therapy on the development of tolerance during continuous therapy with nitroglycerin.

OBJECTIVES: This study examined the effects of concurrent diuretic therapy on the hemodynamic responses to short-term and sustained therapy with transdermal nitroglycerin. BACKGROUND: Sodium retention and plasma volume expansion occur during therapy with nitroglycerin and may play a role in the loss of nitroglycerin effects during sustained therapy. METHODS: Twenty-two normal male volunteers were treated for 1 week with either hydrochlorothiazide and amiloride (50 + 5 mg) (n = 11) or placebo (n = 11) in a randomized, double-blind fashion. All 22 subjects then received continuous transdermal nitroglycerin (19 +/- 1 mg/24 h) for 5 to 7 days. RESULTS: On the first and last day of transdermal nitroglycerin therapy, standing heart rate, systolic blood pressure and hematocrit values were assessed at 8, 9 and 10 AM and 12 noon. Heart rate and blood pressure responses to sublingual nitroglycerin (0.6 mg) were also evaluated before and after sustained transdermal nitroglycerin therapy. A significant loss of the hemodynamic effects of transdermal and sublingual nitroglycerin occurred during sustained therapy in both the diuretic and placebo therapy groups. In both groups, transdermal nitroglycerin therapy was associated with a significant decrease in hematocrit that persisted for the entire treatment period. CONCLUSIONS: These results suggest that diuretic therapy does not prevent plasma volume expansion or the loss of hemodynamic effects during sustained transdermal nitroglycerin therapy. The persistent decrease in hematocrit suggests that plasma volume expansion plays a role in the attenuation of nitrate effects. It also provides evidence of continued vascular activity of nitroglycerin despite loss of systemic hemodynamic effects.

Administration, Cutaneous↗
PubMed1992

Psychiatric diagnoses of maltreated children: preliminary findings.

The study sample consists of 96 children (61 maltreated, 35 controls) between 5 and 10 years of age. The two groups of subjects were compared on diagnoses as determined by the administration of the Diagnostic Interview for Children and Adolescents, Revised 6th Version (DICA-6-R) as well as clinical DSM-III-R diagnoses. Children who had suffered maltreatment exhibited significantly greater incidences of attention deficit hyperactivity disorder, oppositional disorder and post-traumatic stress disorder diagnoses than did controls, on both child and parent DICA interviews. The children's interviews revealed that maltreated children present with a significant incidence of psychotic symptomatology as well as personality and adjustment disorders. Conversely, conduct and mood disorders emerged as significant factors in the parent interviews, with the maltreated group showing significantly greater incidence of these diagnoses.

Child↗
PubMed1992

Psychiatric diagnoses of abusive mothers. A preliminary report.

The Structured Clinical Interview for DSM-III-R diagnoses of 54 mothers who had maltreated their children were compared with those of 37 controls. The maltreatment group showed a significantly greater incidence of both current and past diagnoses. Maltreating mothers exhibited a significantly greater incidence of current mood disorder, alcohol abuse, and personality disorder than did controls. The results indicate that past abuse of cocaine, alcohol, other substances and past mood disorders were significantly more prevalent among the maltreatment sample than among controls. Mothers who had maltreated their children were significantly more likely to have histories of posttraumatic stress disorder than were controls.

Adult↗
PubMed1992

Differences in neuropsychological and academic achievement between adolescent delinquents and status offenders.

OBJECTIVE: This study sought to determine whether neurocognitive factors could discriminate delinquents brought before a juvenile court in a large urban area from nondelinquent status offenders brought before the same court. METHOD: Psychological tests were administered to 216 adolescents, aged 13-15 years, presenting to a large urban juvenile court. One hundred ten delinquents (65 male and 45 female) were compared to 106 high-risk nondelinquents (65 male and 41 female) on the WISC-R subtests, the Wide Range Achievement Test, and the Memory for Designs Test. RESULTS: Discriminant analysis revealed that the male delinquents could not be discriminated from the comparison group of male status offenders on the basis of scores on any of the measures. Among the female subjects, scores on reading, arithmetic, digit span, and picture completion subtests and the Memory for Designs Test differed significantly between groups, with some of the findings favoring status offenders and others favoring delinquents. CONCLUSIONS: Overall, the findings did not support the hypothesis that inferior intelligence is an independent risk factor for delinquent behavior.

Achievement↗
PubMed1992

Medical and developmental histories of maltreated children.

This paper represents a first attempt at delineating and summarizing the issues in a child's medical and developmental history associated with the probability of suffering abuse. The sample consisted of 96 children between 5 and 10 years of age, 61 of whom had been maltreated and 35 of whom served as controls. There were 22 items about which the medical and developmental histories of the maltreated children revealed a significantly greater risk than those of the controls. A factor analysis revealed that 78% of the variance in these items can be represented by eight independent factors. None of these factors was dominant; rather, each accounted for a significant amount of the variation among the original items. The individual items tended to load on the four strongest factors in a coherent, interpretable manner: Factor 1 represented behavior problems; factor 2, neonatal issues and failure to thrive; factor 3, familial disruption, with the child suffering mental illness and/or head injury; and factor 4, a "difficult" temperament during the first year of life. We conclude there are numerous independent factors in the medical and developmental histories of maltreated children which should be considered by pediatricians involved in cases of child abuse and neglect.

Analysis of Variance↗
PubMed1992

Learning by teaching. A resident-taught oral therapy program for acute diarrhea.

An educational program on oral rehydration therapy (ORT) for diarrhea was instituted in our residents' continuity clinics to evaluate the impact that residents teaching parents would have on the knowledge and practices of both groups. Sixty-one residents and 287 parents answered the initial written questionnaire before the teaching program began, and 48 residents and 147 parents completed a second questionnaire at the end of the program. Nineteen residents in two clinics were told to participate frequently in teaching the parents, while 29 residents in three other clinics were given no such instructions. The parents were divided into three groups: 58 received teaching and an instructional handout on the management of diarrhea; 73 received only the instructional handout; and 16 received neither intervention. The 19 "teaching" residents had a significantly improved overall score compared with the "nonteaching" residents (p < .03). No improvement was found in the scores of the 58 parents who received teaching compared with those of the 89 parents who received either a handout or no educational intervention. We conclude that active teaching of ORT may improve the knowledge and practices of residents, but that single teaching encounters, whether or not accompanied by written instructions, may have little impact on parents.

Acute Disease↗
PubMed1992

Maternal toxemia is associated with reduced incidence of germinal matrix hemorrhage in premature babies.

To evaluate prenatal and perinatal risk factors for development of germinal matrix hemorrhage-intraventricular hemorrhage (GMH-IVH), we conducted a prospective epidemiologic study of 449 babies whose birth weight was less than 1501 grams. This study permitted us to test our previously generated hypothesis that babies born to mothers with preeclampsia were at substantially reduced risk of developing GMH-IVH. Seventy-two (16%) of the babies in this population developed GMH-IVH. One (2.5%) of the 40 mothers with a diagnosis of preeclampsia and 71 (17.4%) of 409 mothers without preeclampsia gave birth to babies who developed GMH-IVH. GMH-IVH was seen in 6/107 (5.6%) of babies born to women with hypertension including 4/69 (5.8%) of babies born to women with pregnancy-induced hypertension, compared to 66/352 (18.8%) of babies born to mothers who did not have hypertension. Only 7.3% (8/108) of babies born to women who had proteinuria had GMH-IVH, compared to 18.3% (64/350) of babies whose mothers did not have proteinuria. GMH-IVH was seen in 5/89 (5.6%) of babies whose mothers had both hypertension and proteinuria, whereas 63/332 (19%) of babies born to mothers who lacked both factors, developed GMH-IVH. In stepwise logistic regression analysis, these significant findings were not explained by the presence of labor, postnatal acidemia, need for intubation, antenatal administration of steroids, birth weight, or gestational age. In addition, we found that maternal receipt of magnesium sulfate was associated with diminished risk of GMH-IVH even in those babies born to mothers who apparently did not have preeclampsia.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Hemorrhage↗
PubMed1992

Electrocardiographic R-wave changes during cardiac surgery.

The diagnostic accuracy of exercise electrocardiography has been improved by incorporation of R-wave gain factor to correct the measured ST-segment changes. If marked changes in R-wave amplitude occur in individual patients during cardiac operations, a similar gain factor correction may improve the intraoperative diagnosis of myocardial ischemia. This investigation was designed to determine the frequency and magnitude of intraoperative V5 R-wave amplitude changes during cardiac operations. Electrocardiograms were recorded from 83 patients while patients were awake, anesthetized (baseline), after placement of the Favaloro and Canadian sternal retractors, and at end-operation. Compared with baseline values, placement of the Canadian sternal retractor was associated with a reduction in V5 R-wave amplitude from 15 +/- 1 to 10 +/- 1 mm (mean +/- SEM), in V5 S-wave amplitude from 3.5 +/- 0.4 to 1.7 +/- 0.3 mm, and in absolute ST-segment deviation from 0.50 +/- 0.04 to 0.39 +/- 0.05 mm. Changes in V5 R-wave amplitude were correlated with changes in ST-segment deviation in patients with baseline ST-segment deviations greater than or equal to 0.5 mm (r = 0.55, P = 0.0004, n = 37). Changes associated with the Favaloro retractor and the respiratory cycle were less marked. However, the V5 R-wave amplitude was decreased from 15 +/- 1 to 9 +/- 1 mm at end-operation. In conclusion, sternal spreading with the Canadian retractor was associated with marked reductions in V5 R- and S-wave amplitudes and ST-segment deviations. Marked changes in V5 R-wave amplitude persisted after sternal closure.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1991

Stimulant medication and attention deficit-hyperactivity disorder. The child's perspective.

Fifty-eight children receiving stimulant medication for attention deficit-hyperactivity disorder at referral clinics for learning disabilities at two teaching hospitals in Massachusetts were invited to participate in a study of their knowledge and attitudes. The 45 respondents and parents completed separate questionnaires concerning how they felt about receiving stimulant medication. Eighty-nine percent of the children felt that the medication was helpful and 78% liked or were indifferent to it despite a high rate (85%) of reported side effects. The five children (11%) who responded that they would stop taking stimulant medication if they could were more likely to perceive the medication as unhelpful and were receiving standard methylphenidate hydrochloride rather than a long-acting preparation. We conclude that children's perspectives on medication should be elicited directly and sustained-release medication may be more acceptable to children with attention deficit-hyperactivity disorder.

Adolescent↗
PubMed1991

Financing health services in school-based clinics. Do nontraditional programs tap traditional funding sources?

This telephone survey of directors of 50 school-based clinics (SBCs) examined the influence of organizational factors on use of traditional funding sources, such as Medicaid and private insurance. These factors included: initial funding source (Robert Wood Johnson Foundation's School-Based Adolescent Health Care Program vs. comparison), administrative structure, age of clinic, and state Medicaid policy. Results indicated that over half (51%) of the clinics used Medicaid as a funding source to some extent, while fewer (32%) used private insurance. Use of Medicaid and private insurance, however, varied with the initial funding source, administrative structure, and age of the clinic. Initial funding source and age of the clinic were the strongest predictors of Medicaid usage. Barriers to traditional funding sources, as well as methods used to overcome constraints, are discussed. The importance of the link between a nontraditional health care delivery system, the school-based clinic, and the traditional funding sources of Medicaid and private insurance is examined in light of the organizational factors which facilitate this link.

Ambulatory Care Facilities↗
PubMed1991

Changes in the pharmacodynamic response to fentanyl in neonates during continuous infusion.

Tolerance to opioid-induced sedation has been reported in neonates sedated with fentanyl by continuous infusion while undergoing extracorporeal membrane oxygenation. We undertook a prospective analysis of eight newborn infants sedated with fentanyl during extracorporeal membrane oxygenation therapy for respiratory failure. We recorded daily mean fentanyl infusion rate, measured serial plasma fentanyl concentrations, and documented the occurrence of spontaneous motor activity or respiratory effort. Mean fentanyl infusion rate increased steadily during the period of infusion from a mean of 9.2 +/- 1.9 (SEM) micrograms/kg per hour on day 1 to a mean of 21.9 +/- 4.5 micrograms/kg per hour by day 6. Mean plasma fentanyl concentrations increased steadily during the period of fentanyl infusion from 3.1 +/- 1.1 (SEM) ng/ml on day 1 to 13.9 +/- 3.2 ng/ml on day 6. All infants exhibited movement in response to gentle tactile stimulation throughout the period of infusion, and seven of eight infants manifested spontaneous movement of the extremities and eye opening. Our results indicate that when fentanyl is used for sedation in neonates, the plasma concentrations required for satisfactory sedation steadily escalate, possibly indicating the rapid development of tolerance to the sedating effects of fentanyl.

Extracorporeal Membrane Oxygenation↗
PubMed1991

Posttraumatic stress disorder among children clinically diagnosed as borderline personality disorder.

Using the Diagnostic Interview for Children and Adolescents, Revised Version (DICA-C-R), the authors evaluated 19 children ages 7 to 14 who had recently been clinically diagnosed as borderline personality disorder by DSM-III-R criteria. The results reveal that 78.9% of these children reported significant traumatic experiences, with 36.8% fitting DICA-C-R criteria for posttraumatic stress disorder. These findings raise the possibility that a diagnosis of borderline personality in childhood can often represent posttraumatic stress disorder.

Adolescent↗
PubMed1991

Counter-regulatory responses to continuous and intermittent therapy with nitroglycerin.

BACKGROUND: Vasodilator therapy may be associated with reflex counter-regulatory responses, and these responses may play a role in the development of tolerance to nitroglycerin (GTN). METHODS AND RESULTS: Standing systolic blood pressure, body weight, urinary sodium, and hormonal responses to continuous (n = 10) and intermittent (n = 10) transdermal GTN administration were studied in normal volunteers. There was rapid attenuation of the hypotensive response to transdermal GTN therapy in the continuous but not in the intermittent therapy group. Significant weight gain and sodium retention occurred during continuous but not during intermittent GTN therapy. This was accompanied by a greater decrease in hematocrit in the continuous group, a finding that suggests that plasma volume expansion occurred during continuous GTN therapy. Continuous GTN therapy was associated with increases in plasma norepinephrine, atrial natriuretic peptide, arginine, vasopressin, and plasma renin activity. A different pattern of neurohormonal response was seen during intermittent therapy, with values tending to return to baseline levels after the nitrate-free interval. CONCLUSIONS: Continuous transdermal GTN therapy leads to counter-regulatory responses associated with sodium retention and probable plasma volume expansion. By contrast, intermittent transdermal GTN therapy is associated with a different pattern of hormonal response, the lack of sodium retention and no evidence of plasma volume expansion. It is likely that these counter-regulatory responses play an important role in the attenuation of nitrate effects.

Administration, Cutaneous↗
PubMed1991

Labor and delivery characteristics and the risk of germinal matrix hemorrhage in low birth weight infants.

To assess the influence of labor and delivery events on the risk of germinal matrix hemorrhage in preterm newborns, we conducted a review of data collected on 449 babies who weighed 1.5 kg or less. Babies delivered vaginally were more likely to have germinal matrix hemorrhage than were babies delivered abdominally (odds ratio, 2.5; 95% confidence interval, 1.4,3.3). Among babies delivered vaginally, the risk of germinal matrix hemorrhage was increased by 39% if labor lasted more than 12 hours. Among babies delivered abdominally, the occurrence of any labor was accompanied by a 150% increased risk of germinal matrix hemorrhage. The only indication for abdominal delivery associated with an increased risk of germinal matrix hemorrhage was impending amnionitis (odds ratio, 2.6; 95% confidence interval, 1.2,5.7), whereas the only indication associated with a decreased risk was preeclampsia (odds ratio, 0.2; 95% confidence interval, 0.6). Epidural and local anesthesia were associated with a reduced risk of germinal matrix hemorrhage among babies delivered abdominally. We conclude that delivery practices, or their indications, appear to influence the risk of germinal matrix hemorrhage in low birth weight babies.

Cerebral Hemorrhage↗
PubMed1991

Continuous arterial and venous blood gas monitoring during cardiopulmonary bypass.

A new monitoring technique, based on optical fluorescence chemistry, allows continuous monitoring of all blood gas variables during cardiopulmonary bypass. To evaluate the clinical performance of this monitor, we drew 220 arterial and 216 venous blood samples from 15 patients, and simultaneous blood gas values displayed by the monitor were compared with standard laboratory measurements. The continuous monitor predicted laboratory values with varying degrees of accuracy. (R2 values by linear regression: arterial oxygen tension 0.86, venous oxygen tension 0.36, arterial carbon dioxide tension 0.58, venous carbon dioxide tension 0.72, arterial pH 0.53, venous pH 0.58; pH 0.53, venous pH 0.58; p less than 0.0001). Monitor values of arterial oxygen tension overestimated laboratory values (bias = + 43.5 mm Hg), but the laboratory reference method likely underestimated true arterial oxygen tension in the high range achieved on bypass. Monitoring of venous oxygen tension was imprecise (precision = +/- 6.51 mmHg), regardless of whether stable conditions existed during the sampling period. Monitoring of carbon dioxide tension and pH showed small bias (carbon dioxide tension within 2 mm Hg, pH within 0.03) and good precision (carbon dioxide tension within 3 mm Hg, pH within 0.03). With the development of unstable conditions on bypass, monitor arterial oxygen tension values showed a changing relationship to corresponding laboratory values. In conclusion, arterial and venous carbon dioxide tension and pH monitoring provide acceptably accurate alternatives to laboratory measurement of these variables during cardiopulmonary bypass. Arterial oxygen tension monitoring accurately indicates changes in oxygen tension in the arterial oxygen tension range typically produced during extracorporeal circulation. Oxygen tension monitoring in the venous oxygen tension range is too imprecise for clinical decision-making purposes.

Aged↗
PubMed1990

Symptom differences in acute and chronic presentation of childhood post-traumatic stress disorder.

The authors report on 24 children diagnosed with post-traumatic stress disorder (PTSD) according to DSM-III criteria. Each child was designated as presenting with acute or chronic PTSD depending upon the duration of symptoms. Children with the acute form of PTSD presented with a relative increase in spontaneously acting as though the trauma were recurring upon real or symbolic exposure, difficulty falling asleep, hypervigilance, nightmares, exaggerated startle response, and generalized anxiety/agitation. Those presenting with the chronic form had relative increases in symptoms of detachment, restricted range of affect, dissociative episodes, sadness, and a belief that life will be too hard.

Adolescent↗
PubMed1990

Child maltreatment histories among runaway and delinquent children.

The records of 378 children presenting to a juvenile court were reviewed for histories of child maltreatment, based on evidence from a formal investigative process by the Department of Social Services. The children came from two groups: delinquents, who had engaged in criminal activity, and status offenders, whose legal involvement was due to non-criminal behavior, such as running away and truancy. Fifty-five percent of the status offenders and 45% of the delinquents had substantiated histories of maltreatment. The percent of status offenders who had been sexually abused was seven times higher among runaways (35%) than among the other members of the group (5%). The percent of delinquents who had been physically maltreated was significantly greater among those convicted of committing violent crimes (27%) than among the non-violent delinquents (14%). Thus, maltreatment may contribute significantly to delinquent behavior.

Adolescent↗