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Biomedical subjects

D J Cox

Publications and source records attributed to D J Cox.

At least 37 records · Page 2Linked to original sources

Thrombelastogram reveals hypercoagulability after administration of gelatin solution.

We have compared the effects of gelatin, low molecular weight hydroxyethyl starch (HES) or albumin on tests of haemostasis and on the thrombelastogram in 42 ASA I patients undergoing total hip or knee replacement. Patients were allocated randomly to receive one of the three blood substitutes to obtain moderate intraoperative haemodilution. Blood loss and packed red cell infusion was the same in each group. A greater amount of gelatin was given (1.5 times the measured blood loss) because of its shorter half-life. There was a statistically significant but clinically negligible decrease in platelets count, prothrombin time and fibrinogen, and an increase in bleeding time in all groups. Platelets were slightly but significantly lower after HES. Haemodilution was comparable between groups. TEG showed a state of hypercoagulability in the gelatin group with a significant decrease in r, r + k and an increase in alpha angle.

Adult↗

Self-prepared heparinized syringes for measuring ionized magnesium in critical care patients.

We have compared ionized magnesium assays in the Nova 8 electrolyte analyser using dry balanced heparinized syringes and self-prepared heparinized syringes. Thirty blood specimens were obtained into syringes either operator-prepared with liquid sodium heparin or commercially manufactured dry balanced heparinized syringes. There was a good correlation between results from the two syringes. The mean difference between sampling methods was 0.01 mmol litre-1 (95% confidence index -0.05 to 0.08 mmol litre-1). The correlations for sodium, potassium and ionized calcium assays were similarly close. The relationship between sampling methods was close enough to justify the clinical use of self-prepared syringes, with potential economies in clinical costs.

Anticoagulants↗

Differences in toileting habits between children with chronic encopresis, asymptomatic siblings, and asymptomatic nonsiblings.

No studies have compared toileting-specific behaviors of encopretic children with those of asymptomatic children and have controlled for environmental factors such as parental attitudes, parenting styles, and bathroom facilities. This study prospectively examined the toileting habits of 86 chronically encopretic children compared with those of 27 asymptomatic siblings and 35 asymptomatic nonsiblings. Although encopretic children experienced significantly more soiling than did controls, the total number of daily bowel movements passed in the toilet (+/-SD) was comparable in the three groups (.92 +/- .76 in encopretic children compared with 1.14 +/- .43 and 1.08 +/- .47 in siblings and nonsiblings, respectively). Encopretic children experienced pain with defecation more often than did controls. During the 14-day study period, encopretic children complained of pain on 2.75 +/- 4.03 days compared with .58 +/- 1.84 days among sibling controls and 2.31 +/- 3.21 days among nonsibling controls. The mean pain score in encopretic children was .76 +/- 1.00 compared with .05 +/- .15 and .26 +/- .38 among siblings and nonsiblings, respectively. All three groups of children sat on the toilet without parental prompting the same number of times each day. In summary, children with chronic encopresis do not seem to avoid toileting, and they exhibit toileting behaviors that are very similar to those of asymptomatic siblings as well as to those of nonsibling controls.

Animals↗

Biopsychobehavioral model of severe hypoglycemia. II. Understanding the risk of severe hypoglycemia.

OBJECTIVE: To evaluate the clinical/research utility of the biopsycho-behavioral model of severe hypoglycemia in differentiating patients with and without a history of severe hypoglycemia and in predicting occurrence of future severe hypoglycemia. RESEARCH DESIGN AND METHODS: A total of 93 adults with type 1 diabetes (mean age 35.8 years, duration of diabetes 16 +/- 10 years, HbA1 8.6 +/- 1.8%), 42 of whom had a recent history of recurrent severe hypoglycemia (SH) and 51 who did not (NoSH), used a handheld computer for 70 trials during 1 month recording cognitive-motor functioning, symptoms, blood glucose (BG) estimates, judgments concerning self-treatment of BG, actual BG readings, and actual treatment of low BG. For the next 6 months, patients recorded occurrence of severe hypoglycemia. RESULTS: SH patients demonstrated significantly more frequent and extreme low BG readings (low BG index), greater cognitive-motor impairments during hypoglycemia, fewer perceived symptoms of hypoglycemia, and poorer detection of hypoglycemia. SH patients were also less likely to treat their hypoglycemia with glucose and more likely to treat with general foods. Low BG index, magnitude of hypoglycemia-impaired ability to do mental subtraction, and awareness of neuroglycopenia, neurogenic symptoms, and hypoglycemia correlated separately with number of SH episodes in the subsequent 6 months. However, only low BG index, hypoglycemia-impaired ability to do mental subtraction, and awareness of hypoglycemia entered into a regression model predicting future severe hypoglycemia (R2 = 0.25, P < 0.001). CONCLUSIONS: Patients with a history of severe hypoglycemia differed on five of the seven steps of the biopsychobehavioral model of severe hypoglycemia. Helping patients with a recent history of severe hypoglycemia to reduce the frequency of their low-BG events, become more sensitive to early signs of neuroglycopenia and neurogenic symptoms, better recognize occurrence of low BG, and use fast-acting glucose more frequently in the treatment of low BG, may reduce occurrence of future severe hypoglycemia.

Adult↗

Biopsychobehavioral model of risk of severe hypoglycemia. Self-management behaviors.

OBJECTIVE: To identify self-management antecedents of low blood glucose (BG) (< 3.9 mmol/l) that might be easily recognized, treated, or avoided altogether. RESEARCH DESIGN AND METHODS: Ninety-three adults with type 1 diabetes (age, 35.8 +/- 8 years [mean +/- SD]; duration of diabetes, 17.0 +/- 11 years; daily insulin dose, 0.58 +/- 0.18 U/kg; and HbAlc, 8.6 +/- 1.8%) were recruited to participate in the study. Of the 93 subjects, 42 had a history of severe hypoglycemia (SH), defined as two or more hypoglycemic episodes in the preceding 12 months, and 51 subjects had no history of SH (No-SH) in the same time period. Before each of 70 BG measurements obtained over a 3-week period, subjects used a handheld computer to record whether their most recent insulin, food, and exercise was more than, less than, or the same as usual. Associations among self-management behaviors preceding BG readings < 3.9 mmol/l versus those preceding BG readings of 5.6-7.8 mmol/l were determined using chi 2 tests, analyses of variance, and logistic regression analyses. RESULTS: Analysis of 6,425 self-management/self-monitoring of BG events revealed that the usual amounts of insulin, food, and exercise preceded the events 58.3% of the time. No significant differences were observed for changes in insulin before readings of BG < 3.9 mmol/l versus 7.8 < BG > 5.6 mmol/l, but significantly less food (P < 0.01) was eaten and more exercise (P < 0.001) was performed before the low BG measurement. No interactions between SH and No-SH groups and management behaviors were observed. However, each of the three management variables entered significantly in a logistic model that predicted 61% of all readings of BG < 3.9 mmol/l. CONCLUSIONS: Subjects with a history of SH did not report managing their diabetes differently from those with no such history. Specifically, when low BG occurred, the preceding management behaviors, although predictive of low BG, were not different in SH and No-SH subjects. Overall, self-management behaviors did not distinguish SH from No-SH subjects. Thus, even though it might be beneficial for all patients to review their food and exercise management decisions to reduce their frequency of low BG, an educational intervention whose content stresses insulin, food, and exercise would be unlikely by itself to be sufficient to reduce the frequency of SH.

Adult↗

Behavioral science in diabetes. Contributions and opportunities.

OBJECTIVE: To summarize the current status of behavioral research and practice in diabetes and to identify promising future directions. RESEARCH DESIGN AND METHODS: We review behavioral science contributions to diabetes in self-management and patient empowerment, interventions with children and adolescents, and special problems including blood glucose awareness training and complications such as depression. We also identify emerging areas in which behavioral science stands to make significant contributions, including quality of life, worksite and community programs, interventions using new information technologies, and translation research evaluating practical programs in representative settings. We then discuss the gap between the generally encouraging research on behavioral contributions to diabetes and the infrequent incorporation of such contributions in practice. Suggestions are made for how to close this gap, including ways to increase understanding of behavioral issues, opportunities for funding of key research and implementation questions, and how behavioral science principles can become more integrated into diabetes organizations and care. CONCLUSIONS: Changes are required on the part of behavioral scientists in how they organize and present their research and on the part of potential users of this knowledge, including other health professions, organizations, and funding agencies. Integrating behavioral science advances with other promising genetic, medical, nutritional, technology, health care, and policy opportunities promises not only to broaden our understanding of diabetes but also to improve patient care, quality of life, and public health for persons with diabetes.

Behavioral Sciences↗

Blood glucose awareness training and epinephrine responses to hypoglycemia during intensive treatment in type 1 diabetes.

OBJECTIVE: To determine the effect of blood glucose awareness training (BGAT) on epinephrine and symptom responses to hypoglycemia in patients with type 1 diabetes enrolled in an intensive diabetes treatment (IDT) program. RESEARCH DESIGN AND METHODS: A total of 47 subjects with uncomplicated diabetes (duration 9 +/- 3 years: HbA1c 9.0 +/- 1.2%; reference range 4-6%) enrolled in a 4-month outpatient IDT program were randomized to classes in BGAT (n = 25) (BGAT group) or cholesterol awareness (n = 22) (control group). Subjects underwent stepped hypoglycemic clamp studies before and at completion of IDT. Plasma glucose was lowered from 6.7 mmol/l (baseline) to 4.4, 3.9, 3.3, 2.8, and 2.2 mmol/l over 190 min. Symptoms, counterregulatory hormones, and ability of the subject to estimate their glucose level were assessed at each plateau. At home, subjects used a handheld computer to first estimate and then measure and record blood glucose levels for 70 trials over a 4-week period immediately before IDT and again immediately following the educational intervention. RESULTS: HbA1c decreased in both BGAT group (9.1 +/- 1.4 to 7.9 +/- 1.1%; P < 0.001) and control group (9.0 +/- 1.1 to 7.8 +/- 0.8%; P < 0.001) (NS between groups). Frequency of hypoglycemia (< 3.9 mmol/l) increased in both groups, from 0.45 +/- 0.06 to 0.69 +/- 0.07 episodes per day (P < 0.001) in the BGAT group and from 0.50 +/- 0.08 to 0.68 +/- 0.06 episodes per day (P < 0.05) in the control group NS between groups). Epinephrine responses after IDT were greater in the BGAT group (repeated measure analysis of variance [ANOVA], F = 3.5, P < 0.05). A separate analysis of subjects n = 26) most at risk for hypoglycemia (HbA1c after IDT < 7.8% or an HbA1c improvement of > 2 percentage points) showed that frequency of hypoglycemia increased in both the groups: from 0.50 +/- 0.09 to 0.80 +/- 0.11 episodes per day (P < 0.01) in the BGAT group (n = 14) and from 0.43 +/- 0.11 to 0.75 +/- 0.07 episodes per day (P < 0.05) in the control group (n = 12) (NS between groups). However, the epinephrine response in control subjects decreased with IDT while the response in the BGAT subjects was preserved (repeated measure ANOVA, F = 4.4, P < 0.02). CONCLUSIONS: BGAT is a useful intervention to decrease blunting of counterregulatory responses associated with improved glycemic control and may modify the severity of hypoglycemia associated with improved glycemic control in type 1 diabetes.

Adrenocorticotropic Hormone↗

Contribution of behavior therapy and biofeedback to laxative therapy in the treatment of pediatric encopresis.

A model incorporating physiological, behavioral, and psychological parameters are presented to explain the maintenance and consequences of pediatric encopresis. It was hypothesized that the more comprehensive a treatment in addressing these parameters, the more efficacious it would be and the more children it would benefit. Eighty-seven children between the ages of 6 and 15 with the primary complaint of encopresis were randomly assigned to one of three treatments: (a) Intensive Medical Care (IMC), receiving enemas for disimpaction and laxatives to promote frequent bowel movements; (b) Enhanced Toilet Training (ETT), using reinforcement and scheduling to promote response to defecation urges and instruction and modeling to promote appropriate straining, along with laxatives and enemas; or (c) Biofeedback (BF), directed at relaxing the external anal sphincter during attempted defecation, along with toilet training, laxatives, and enemas. Three months following initiation of treatment, ETT and BF produced similar reductions in soiling/child (76% and 65%) that were superior (p's < .04) to IMC (21%). ETT significantly benefited more children than the other two treatments, employing fewer laxatives and fewer treatment sessions at a lower cost. Consistent with the presented model, reduction in soiling was associated with an increase in bowel movements in the toilet, reduction in parental prompting to use the toilet, and defecation pain. These results demonstrate that ETT should be used routinely with laxative therapy in the treatment of chronic encopresis.

Adolescent↗

Electroencephalographic and psychometric differences between boys with and without attention-deficit/Hyperactivity disorder (ADHD): a pilot study.

Attention-Deficit/Hyperactivity Disorder (ADHD) is reported to have an incidence of 3-5%, and is associated with a variety of interpersonal, academic, and social problem behaviors. There is controversy as to whether ADHD is a learned behavioral or brain dysfunction. Research has explored a variety of measures to assess behavioral and brain dysfunctions in this population, with no consistent and clearly diagnostic results. We investigated whether a new psychometric and a new electroencephalographic procedure would clearly differentiate ADHD. The psychometric was based on DSM-IV criteria and the EEG measure was based on the assumption that ADHD interferes with cognitive transition from one discrete task to another. Parents of four ADHD boys (ages 8-12) and four age- and interest-matched non-ADHD boys completed the ADHD Symptom Inventory, while their sons' EEG was monitored during viewing of a video and reading of a book. For the ADHD boys, this was repeated a second time, 3 months later, to assess test-retest reliability. Both the psychometric and the EEG measures clearly differentiated the two samples (p's < .01) with no overlap in scores, were reliable over 3 months (r = .87), and were significantly correlated with one another (r = .85). While a small sample size, these robust, related and reliable findings suggest that both the psychometric and the psychophysiological EEG measures deserve further replication and exploration.

Attention Deficit Disorder with Hyperactivity↗

Maternal fear of hypoglycemia in their children with insulin dependent diabetes mellitus.

A modified version of the Hypoglycemia Fear Survey (HFS) was used to measure fear of hypoglycemia among mothers of 46 pre-adolescent children with IDDM. Glycosylated hemoglobin (HbA1) levels were measured, and episodes of severe hypoglycemia over the previous year were recorded. The relationships between the child's age, disease duration, HbA1, history of hypoglycemia, and maternal distress concerning hypoglycemia and HFS-P scores were explored. Maternal HFS-P scores were also compared to those of 78 IDDM adults. There was no relationship between children's age, disease duration, number of severe hypoglycemic episodes and maternal HFS-P scores. However, mothers whose children had passed out with hypoglycemia had higher HFS-P scores. Correlations between mothers' responses concerning their children's history of hypoglycemia and HFS-P scores suggested that their degree of distress associated with events which occurred when their child was asleep, or in a social situation was related to their total HFS-P, and Behavior and Worry subscores. Mothers demonstrated significantly greater fear than did adult patients themselves. The HFS-P may be an appropriate instrument for examining the psychological impact of differing treatment regimens on families of children with IDDM.

Adult↗

Assessment of risk for severe hypoglycemia among adults with IDDM: validation of the low blood glucose index.

OBJECTIVE: To evaluate the clinical/research utility of the low blood glucose index (LBGI), a measure of the risk of severe hypoglycemia (SH), based on self-monitoring of blood glucose (SMBG). RESEARCH DESIGN AND METHODS: There were 96 adults with IDDM (mean age 35+/-8 years, duration of diabetes 16+/-10 years, HbA1 8.6+/-1.8%), 43 of whom had a recent history of SH (53 did not), who used memory meters for 135+/-53 SMBG readings over a month, and then for the next 6 months recorded occurrence of SH. The SMBG data were mathematically transformed, and an LBGI was computed for each patient. RESULTS: The two patient groups did not differ with respect to HbA1, insulin units per day, average blood glucose (BG) and BG variability. Patients with history of SH demonstrated a higher LBGI (P < 0.0005) and a trend to be older with longer diabetes duration. Analysis of odds for future SH classified patients into low- (LBGI <2.5), moderate- (LBGI 2.5-5), and high- (LBGI >5) risk groups. Over the following 6 months low-, moderate-, and high-risk patients reported 0.4, 2.3, and 5.2 SH episodes, respectively (P = 0.001). The frequency of future SH was predicted by the LBGI and history of SH (R2 = 40%), while HbA1, age, duration of diabetes, and BG variability were not significant predictors. CONCLUSIONS: LBGI provides an accurate assessment of risk of SH. In the traditional relationship history of SH-to-future SH, LBGI may be the missing link that reflects present risk. Because it is based on SMBG records automatically stored by many reflectance meters, the LBGI is an effective and clinically useful on-line indicator for SH risk.

Adult↗

Anorectal manometric examination in encopretic-constipated children.

PURPOSE: We have investigated the use of anorectal manometry to distinguish encopretic-constipated children (n = 88) from sibling controls (n = 16) and nonsibling controls (n = 11). METHODS: Study variables included manometrically determined resting and maximum voluntary anal sphincter pressure, depth and speed of rectoanal inhibitory reflex, minimum rectal volume sensation, critical distending volume for fecal urgency, rectal and anal pressure responses during attempted defecation, and ability to defecate a water-filled balloon. RESULTS: Change in anal sphincter pressure during attempted defecation (P = 0.03), gradient between rectal and sphincter pressure during attempted defecation (P = 0.02), critical distending volume for fecal urgency (P = 0.02), and ability to defecate a water-filled balloon (P = 0.05) distinguished encopretic-constipated from control children. The change in rectal pressure associated with the rectoanal inhibitory reflex just escaped significance at P = 0.07. CONCLUSIONS: Anal sphincter spasm and megacolon are pathophysiologic abnormalities associated with pediatric constipation-encopresis.

Adolescent↗

Use of heparinase modified thrombelastography in liver transplantation.

Severe coagulopathies can occur during liver transplantation, particularly after reperfusion of the grafted liver. Heparin release has been proposed as one of the factors contributing to this coagulopathy. We have analysed the thrombelastograph (TEG) traces of 55 patients after reperfusion using native and heparinase-treated samples. In almost all cases an abnormal native TEG was improved in vitro by heparinase, demonstrating the presence of heparin or a heparin-like substance. The heparinase-modified TEG allowed assessment of the underlying coagulation status, providing a rational guide to blood component replacement or treatment of fibrinolysis.

Blood Coagulation Disorders↗

Symmetrization of the blood glucose measurement scale and its applications.

OBJECTIVE: To introduce a data transformation that enhances the power of blood glucose data analyses. RESEARCH DESIGN AND METHODS: In the standard blood glucose scale, hypoglycemia (blood glucose, < 3.9 mmol/l) and hyperglycemia (blood glucose, > 10 mmol/l) have very different ranges, and euglycemia is not central in the entire blood glucose range (1.1-33.3 mmol/l). Consequently, the scale is not symmetric and its clinical center (blood glucose, 6-7 mmol/l) is distant from its numerical center (blood glucose, 17 mmol/l). As a result, when blood glucose readings are analyzed, the assumptions of many parametric statistics are routinely violated. We propose a logarithmic data transformation that matches the clinical and numerical center of the blood glucose scale, thus making the transformed data symmetric. RESULTS: The transformation normalized 203 out of 205 data samples containing 13,584 blood glucose readings of 127 type 1 diabetic individuals. An example illustrates that the mean and standard deviation based on transformed, rather than on raw, data better described subject's blood glucose distribution. Based on transformed data: 1) the low blood glucose index predicted the occurrence of severe hypoglycemia, while the raw blood glucose data (and glycosylated hemoglobin levels) did not; 2) the high blood glucose index correlated with the subjects' glycosylated hemoglobin (r = 0.63, P < 0.001); and 3) the low plus high blood glucose index was more sensitive than the raw data to a treatment (blood glucose awareness training) designed to reduce the range of blood glucose fluctuations. CONCLUSIONS: Using symmetrized, instead of raw, blood glucose data strengthens the existing data analysis procedures and allows for the development of new statistical techniques. It is proposed that raw blood glucose data should be routinely transformed to a symmetric distribution before using parametric statistics.

Adult↗