Biomedical subjects

D Tate

Publications and source records attributed to D Tate.

At least 19 recordsLinked to original sources

PubMed2003

Outbreak of Pseudomonas aeruginosa folliculitis associated with a swimming pool inflatable.

On 18 February 2002, the Communicable Disease Unit was notified by the local Public Health Service Laboratory of a child with a positive skin swab for Pseudomonas aeruginosa. This child had attended the local swimming pool and played on an inflatable, subsequently presenting to a Primary Care Nurse Practitioner with folliculitis. A total of 35 cases was identified during the outbreak. This paper describes a case-control study and microbiological sampling of the cases, the suspected inflatable and a survey of 10 swimming pool inflatables in the local area. The odds ratio for developing folliculitis following use of the inflatable was 12 (95% CI 1.05-136.80). The strain of P. aeruginosa found on the inflatable was identical to that obtained from skin swabs of cases. Nine of 10 (90%) of the inflatables sampled were colonized by P. aeruginosa. Attention should be given to the problem of routine decontamination of swimming pool inflatables. P. aeruginosa folliculitis needs to be considered in the differential diagnosis of skin rashes in children, especially in Primary Care.

Case-Control Studies↗

PubMed2001

Treatment of canine hemangiopericytomas with photodynamic therapy.

BACKGROUND AND OBJECTIVES: Canine hemangiopericytomas are a commonly occurring neoplasm with a clinical course of recurrence after surgical removal. This study sought to evaluate Photochlor (HPPH) photodynamic therapy (HPPH-PDT) as an adjuvant therapy to prevent recurrence of tumor after surgical removal. STUDY DESIGN/MATERIALS AND METHODS: Sixteen dogs with naturally occurring hemangiopericytomas were treated with surgical removal of the tumor followed by PDT using Photochlor as the photosensitizer. Photochlor was injected intravenously at a dose of 0.3 mg/kg. Forty-eight hours later the treatment consisted of surgical removal of the tumor followed by HPPH-PDT. RESULTS: Nine dogs (56%) had recurrence of tumor from 2 to 29 (median 9) months after treatment. These results are comparable or not as good as other forms of therapy. CONCLUSIONS: Photochlor photodynamic therapy applied after surgery appears to have no advantage over other forms of therapy in regards to preventing recurrence. Delayed wound healing and infections are problematic and make HPPH-PDT an undesirable addition to surgery for the treatment of this tumor type.

Animals↗

PubMed2001

Impact of demographic and medical factors on satisfaction with life after spinal cord injury: a normative study.

OBJECTIVE: The aim of this study was (1) to examine demographic and medical predictors of the Satisfaction With Life Scale (SWLS) among individuals with spinal cord injury (SCI) and (2) to provide a normative table for the SWLS that includes appropriate adjustments for the most important predictors of life satisfaction. STUDY DESIGN: We examined predictors of the SWLS including age, education, sex, race, injury duration, number of rehospitalizations, marital status, employment status, SCI etiology, and level of neurological impairment. PARTICIPANTS: Individuals in the National Spinal Cord Injury Statistical Center database [from 18 SCI model systems (1995-1999)] undergoing follow-up assessment were included for study. OUTCOME MEASURE: Satisfaction With Life Scale. RESULTS: Univariate analyses indicated that marital and employment status, race, sex, education, and injury duration were significant factors associated with scores on the SWLS. In general, individuals who were female, white, married, and currently employed and had a higher education and longer injury duration reported significantly higher scores on the SWLS (P < .01). Effect-size estimates for these factors ranged from 0.16 to 0.41. Regression analyses showed that education, employment status, and injury duration were the strongest unique predictors of satisfaction with life but accounted for only 10% of the variance. CONCLUSION: The SWLS is a global measure of life satisfaction and is relatively unrelated to demographic and medical characteristics. Normative tables are provided for epidemiologic comparison.

Adolescent↗

PubMed2001

Effects of antecedent prolonged exercise on subsequent counterregulatory responses to hypoglycemia.

In the present study the hypothesis tested was that prior exercise may blunt counterregulatory responses to subsequent hypoglycemia. Healthy subjects [15 females (f)/15 males (m), age 27 +/- 1 yr, body mass index 22 +/- 1 kg/m(2), hemoglobin A(Ic) 5.6 +/- 0.5%] were studied during 2-day experiments. Day 1 involved either 90-min morning and afternoon cycle exercise at 50% maximal O2 uptake (VO2(max)) (priorEXE, n = 16, 8 m/8 f) or equivalent rest periods (priorREST, n = 14, 7 m/7 f). Day 2 consisted of a 2-h hypoglycemic clamp in all subjects. Endogenous glucose production (EGP) was measured using [3-3H]glucose. Muscle sympathetic nerve activity (MSNA) was measured using microneurography. Day 2 insulin (87 +/- 6 microU/ml) and plasma glucose levels (54 +/- 2 mg/dl) were equivalent after priorEXE and priorREST. Significant blunting (P < 0.01) of day 2 norepinephrine (-30 +/- 4%), epinephrine (-37 +/- 6%), glucagon (-60 +/- 4%), growth hormone (-61 +/- 5%), pancreatic polypeptide (-47 +/- 4%), and MSNA (-90 +/- 8%) responses to hypoglycemia occurred after priorEXE vs. priorREST. EGP during day 2 hypoglycemia was also suppressed significantly (P < 0.01) after priorEXE compared with priorREST. In summary, two bouts of exercise (90 min at 50% VO2(max)) significantly reduced glucagon, catecholamines, growth hormone, pancreatic polypeptide, and EGP responses to subsequent hypoglycemia. We conclude that, in normal humans, antecedent prolonged moderate exercise blunts neuroendocrine and metabolic counterregulatory responses to subsequent hypoglycemia.

3-Hydroxybutyric Acid↗

PubMed2001

Effect of morning exercise on counterregulatory responses to subsequent, afternoon exercise.

The aim of this study was to determine whether a bout of morning exercise (EXE(1)) can alter neuroendocrine and metabolic responses to subsequent afternoon exercise (EXE(2)) and whether these changes follow a gender-specific pattern. Sixteen healthy volunteers (8 men and 8 women, age 27 +/- 1 yr, body mass index 23 +/- 1 kg/m(2), maximal O(2) uptake 31 +/- 2 ml x kg(-1) x min(-1)) were studied after an overnight fast. EXE(1) and EXE(2) each consisted of 90 min of cycling on a stationary bike at 48 +/- 2% of maximal O(2) uptake separated by 3 h. To avoid the confounding effects of hypoglycemia and glycogen depletion, carbohydrate (1.5 g/kg body wt po) was given after EXE(1), and plasma glucose was maintained at euglycemia during both episodes of exercise by a modification of the glucose-clamp technique. Basal insulin levels (7 +/- 1 microU/ml) and exercise-induced insulin decreases (-3 microU/ml) were similar during EXE(1) and EXE(2). Plasma glucose was 5.2 +/- 0.1 and 5.2 +/- 0.1 mmol/l during EXE(1) and EXE(2), respectively. The glucose infusion rate needed to maintain euglycemia during the last 30 min of exercise was increased during EXE(2) compared with EXE(1) (32 +/- 4 vs. 7 +/- 2 micromol x kg(-1) x min(-1)). Although this increased need for exogenous glucose was similar in men and women, gender differences in counterregulatory responses were significant. Compared with EXE(1), epinephrine, norepinephrine, growth hormone, pancreatic polypeptide, and cortisol responses were blunted during EXE(2) in men, but neuroendocrine responses were preserved or increased in women. In summary, morning exercise significantly impaired the body's ability to maintain euglycemia during later exercise of similar intensity and duration. We conclude that antecedent exercise can significantly modify, in a gender-specific fashion, metabolic and neuroendocrine responses to subsequent exercise.

Adult↗

PubMed2001

Effects of morning hypoglycemia on neuroendocrine and metabolic responses to subsequent afternoon hypoglycemia in normal man.

There is general agreement that prior hypoglycemia blunts subsequent hypoglycemic counterregulatory responses. However, there is considerable debate concerning the timing and number of prior hypoglycemic episodes required to cause this blunting effect. The aim of this study was to determine whether one episode of hypoglycemia could modify neuroendocrine, metabolic, and symptom responses to hypoglycemia induced 2 h later. A total of 24 (12 male and 12 female) young, healthy, overnight-fasted subjects participated in a series of glucose clamp studies. A total of 16 individuals underwent 2 randomized studies of either identical 2-h morning and afternoon hyperinsulinemic (490 +/- 60 pmol/L) hypoglycemia (2.9 +/- 0.1 mmol/L) separated by 2 h or, at least 2 months later, 2-h morning and afternoon hyperinsulinemic (492 +/- 45 pmol/L) euglycemia (5.1 +/- 0.1 mmol/L). A total of 8 other subjects participated in a single experiment that consisted of 2-h morning hyperinsulinemic (516 +/- 60 pmol/L) euglycemia (5.1 +/- 0.1 mmol/L) and 2-h afternoon hyperinsulinemic (528 +/- 66 pmol/L) hypoglycemia (2.9 +/- 0.1 mmol/L) also separated by 2 h. Morning hypoglycemia significantly (P < 0.01) reduced (33-55%) the responses of epinephrine, norepinephrine, glucagon, GH, cortisol, and pancreatic polypeptide during afternoon hypoglycemia. Hypoglycemic symptoms (primarily neuroglycopenic) were also significantly (P < 0.01) reduced during afternoon hypoglycemia. Plasma glucose, insulin, nonesterified fatty acids, glycerol, lactate, beta-hydroxybutyrate (P < 0.01), GH, and cortisol (P < 0.05) levels were significantly increased at the start of afternoon hypoglycemia following morning hypoglycemia. Morning hypoglycemia created an insulin-resistant state during afternoon hypoglycemia. Despite blunted neuroendocrine responses, glucose infusion rates required to maintain hypoglycemia and increases in glucose oxidation were significantly attenuated during afternoon compared with morning hypoglycemia. This was in marked contrast to euglycemic control experiments where glucose infusion rates and nonoxidative glucose disposal were significantly increased during afternoon relative to morning studies. We conclude that in normal man one episode of prolonged, moderate, morning hypoglycemia can produce substantial blunting of neuroendocrine and symptomatic responses to subsequent near-term hypoglycemia, and the induction of posthypoglycemic insulin resistance can compensate for blunted neuroendocrine responses by limiting glucose flux and specifically glucose oxidation during subsequent near-term hypoglycemia.

Adult↗

PubMed2001

Sexual dimorphism in counterregulatory responses to hypoglycemia after antecedent exercise.

After antecedent hypoglycemia, counterregulatory responses to subsequent hypoglycemia exhibit greater blunting in men than in women. Because physical exercise and hypoglycemia share multiple counterregulatory mechanisms, we hypothesized that prior exercise may also result in gender-specific blunting of counterregulatory responses to subsequent hypoglycemia. Thirty healthy subjects (15 women and 15 men; age, 28 +/- 3 yr; body mass index, 23 +/- 1 kg/m2) were studied during 2-d experiments. Day 1 consisted of either identical 90-min morning and afternoon cycle exercise at 50% maximum oxygen expenditure or two 2-h episodes of hyperinsulinemic euglycemia. Day 2 consisted of a 2-h morning hyperinsulinemic-hypoglycemic clamp. Endogenous glucose production was measured using [3-(3)H]glucose. Muscle sympathetic nerve activity was measured using microneurography. Day 2 insulin (540 +/- 36 pmol/liter) and plasma glucose (2.9 +/- 0.06 pmol/liter) levels were similar in men and women during the last 30 min of hypoglycemia. Compared with antecedent euglycemia, d 1 exercise produced significant blunting of d 2 counterregulatory responses to hypoglycemia. Several key d 2 counterregulatory responses were blunted to a greater extent in men than in women: glucagon (men, -105 +/- 14; women, -25 +/- 7 ng/liter; P < 0.0001), epinephrine (men, -2625 +/- 257 pmol/liter; women, -212 +/- 573; P < 0.001), norepinephrine (men, -0.50 +/- 0.12 nmol/liter; women, -0 +/- 0.11; P < 0.001), and muscle sympathetic nerve activity (men, -13 +/- 4; women, -4 +/- 4 bursts/min; P < 0.01). Cardiovascular responses (heart rate and systolic and mean arterial blood pressures) were also more blunted by antecedent exercise in men than in women. After d 1 exercise, the amount of glucose infused during d 2 hypoglycemia in men was increased 6-fold compared with that after d 1 euglycemia. This amount was significantly increased (P < 0.01) compared with the 2-fold (P < 0.01) increment in glucose infusion that was required in women after d 1 exercise. Lipolysis was unaffected by d 1 exercise in women, but was significantly blunted during d 2 hypoglycemia in men. In summary, two bouts of prolonged, moderate exercise (90 min at 50% maximum oxygen expenditure) induced a marked sexual dimorphism in key neuroendocrine (glucagon, catecholamines, and muscle sympathetic nerve activity) and metabolic (glucose kinetic, lipolysis) responses to next day hypoglycemia.

3-Hydroxybutyric Acid↗

PubMed2000

Dosimetric effects of patient displacement and collimator and gantry angle misalignment on intensity modulated radiation therapy.

PURPOSE AND OBJECTIVE: The primary goal of this study was to examine systematically the dosimetric effect of small patient movements and linear accelerator angular setting misalignments in the delivery of intensity modulated radiation therapy. We will also provide a method for estimating dosimetric errors for an arbitrary combination of these uncertainties. MATERIALS AND METHODS: Sites in two patients (lumbar-vertebra and nasopharynx) were studied. Optimized intensity modulated radiation therapy treatment plans were computed for each patient using a commercially available inverse planning system (CORVUS, NOMOS Corporation, Sewickley, PA). The plans used nine coplanar beams. For each patient the dose distributions and relevant dosimetric quantities were calculated, including the maximum, minimum, and average doses in targets and sensitive structures. The corresponding dose volumetric information was recalculated by purposely varying the collimator angle or gantry angle of an incident beam while keeping other beams unchanged. Similar calculations were carried out by varying the couch indices in either horizontal or vertical directions. The intensity maps of all the beams were kept the same as those in the optimized plan. The change of a dosimetric quantity, Q, for a combination of collimator and gantry angle misalignments and patient displacements was estimated using Delta=Sigma(DeltaQ/Deltax(i))Deltax(i). Here DeltaQ is the variation of Q due to Deltax(i), which is the change of the i-th variable (collimator angle, gantry angle, or couch indices), and DeltaQ/Deltax(i) is a quantity equivalent to the partial derivative of the dosimetric quantity Q with respect to x(i). RESULTS: While the change in dosimetric quantities was case dependent, it was found that the results were much more sensitive to small changes in the couch indices than to changes in the accelerator angular setting. For instance, in the first example in the paper, a 3-mm movement of the couch in the anterior-posterior direction can cause a 38% decrease in the minimum target dose or a 41% increase in the maximum cord dose, whereas a 5 degrees change in the θ(1)=20 degrees beam only gave rise to a 1.5% decrease in the target minimum or 5.1% in the cord maximum. The effect of systematic positioning uncertainties of the machine settings was more serious than random uncertainties, which tended to smear out the errors in dose distributions. CONCLUSIONS: The dose distribution of an intensity modulated radiation therapy (IMRT) plan changes with patient displacement and angular misalignment in a complex way. A method was proposed to estimate dosimetric errors for an arbitrary combination of uncertainties in these quantities. While it is important to eliminate the angular misalignment, it was found that the couch indices (or patient positioning) played a much more important role. Accurate patient set-up and patient immobilization is crucial in order to take advantage fully of the technological advances of IMRT. In practice, a sensitivity check should be useful to foresee potential IMRT treatment complications and a warning should be given if the sensitivity exceeds an empirical value. Quality assurance action levels for a given plan can be established out of the sensitivity calculation.

Humans↗

PubMed2000

IgA myeloma of donor origin arising 7 years after allogeneic renal transplant.

We report the case of a 38-year-old man who developed IgA myeloma of donor origin 7 years after allogeneic renal transplant. The diagnosis of multiple myeloma was unequivocal and based on positive results from serum electrophoresis, skeletal survey and bone marrow investigations. The donor origin of the myeloma cells was confirmed by DNA fingerprinting. We believe this is the first reported case of disseminated multiple myeloma of donor origin developing after allogeneic renal transplant and, as such, gives some insight into the natural history and biology of the disease.

Adult↗

PubMed2000

Treatment of canine oral squamous cell carcinomas with photodynamic therapy.

Eleven dogs with naturally occurring oral squamous cell carcinomas were treated with photodynamic therapy (PDT) using Photochlor (HPPH) as the photosensitizer. The largest length of the tumours measured in a two-dimensional plane ranged from 0.9 to 6.8 cm. Seven of the tumours invaded underlying bone as determined by radiograph appearance. Photochlor was injected intravenously at a dose of 0.3 mg kg(-1). Forty-eight hours later the tumours were treated. Tumours with a surface to base depth of greater than 1 cm were surgically reduced to less than 1 cm. Irradiation with 665 nm light with an energy density of 100 J cm(-2) was administered. Eight dogs were considered cured with no tumour recurrence for at least 17 months after treatment. Local treatment of oral squamous cell carcinomas with PDT appears to give results similar to those obtained with surgical removal of large portions of the mandible or maxilla. The cosmetic results with PDT are superior to those of radical surgical removal. The new sensitizer, Photochlor, appears effective for oral squamous carcinomas with results similar to those reported for other sensitizers.

Animals↗

PubMed2000

Tryptophan hydroxylase polymorphisms in suicide victims.

Both environmental and genetic factors appear to contribute to the risk for suicide. The serotonergic system has been implicated in depression, impulsivity and suicidality. Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in the synthesis of serotonin. Suicide has been associated with polymorphisms in intron 7 of the TPH gene. These alleles were studied in samples from 47 deceased Caucasian males as part of the Utah Youth Suicide Study. A 918 base pair fragment spanning the region of interest was amplified. The A218C polymorphism was visualized by restriction fragment length polymorphism (RFLP) and the A779C was sequenced. Neither A218C nor A779C appeared to be associated with suicide in this population. These results did not change when the sample was stratified by age (10-21 years, 22-31 years) or when violent suicides were selected. The complexity of the phenotype of suicide may reflect multiple biological and social etiologic factors, and poses a worthy challenge for genetic studies.

Adolescent↗

PubMed2000

Effects of gender on neuroendocrine and metabolic counterregulatory responses to exercise in normal man.

Significant, sexual dimorphisms exist in counterregulatory responses to commonly occurring stresses, such as hypoglycemia, fasting, and cognitive testing. The question of whether counterregulatory responses differ during exercise in healthy men and women remains controversial. The aim of this study was to determine whether a sexual dimorphism exists in neuroendocrine, metabolic, or cardiovascular responses to prolonged moderate exercise. Sixteen healthy (eight men and eight women) subjects matched for age (28+/-2 yr), body mass index (22+/-1 kg/m2), nutrient intake, and spectrum of physical fitness were studied in a randomized fashion during 90 min of exercise on a cycle ergometer at 80% of their anaerobic threshold (approximately 50% VO2 max). Respiratory quotient and oxygen consumption relative to body weight were identical in men and women. Glycemia was equated (5.3+/-0.2 mmol/L) during exercise via an exogenous glucose infusion. Gender had significant effects on counterregulatory responses during exercise. Arterialized epinephrine (1.05+/-0.2 vs. 0.45+/-0.04 nmol/L), norepinephrine (9.2+/-1.1 vs. 5.8+/-1.1 nmol/L), and pancreatic polypeptide (52+/-6 vs. 37+/-6 pmol/L) were significantly (P<0.01) increased in men compared to women, respectively. Plasma glucagon, cortisol, and GH levels responded similarly in men and women. Insulin values were higher at baseline in men and fell by a greater amount to reach similar levels during exercise compared to those in women. Endogenous glucose production, measured with [3-3H]glucose was similar in men and women. Carbohydrate oxidation was significantly increased in men relative to women (21.2+/-2 vs. 15.6+/-2 mg/kg fat free mass x min; P<0.05). Despite reduced sympathetic nervous system (SNS) drive, lipolytic responses were increased in women. Arterialized blood glycerol (215+/-30 vs. 140+/-20 micromol/L), beta-hydroxybutyrate (54+/-9 vs. 25+/-10 micromol/L), and plasma nonesterified fatty acids (720+/-56 vs. 469+/-103 micromol/L) were significantly (P<0.01) increased in women. In keeping with increased SNS activity, systolic blood pressure and mean arterial pressure were significantly increased (P<0.01) in men. In summary, this study demonstrates that a significant sexual dimorphism exists in neuroendocrine, metabolic, and cardiovascular counterregulatory responses to prolonged moderate exercise in man. We conclude that during exercise, men have increased autonomic nervous system (epinephrine, norepinephrine, pancreatic polypeptide), cardiovascular (systolic, mean arterial pressure) and certain metabolic (carbohydrate oxidation) counterregulatory responses, but that women have increased lipolytic (glycerol, nonesterified fatty acids) and ketogenic (beta-hydroxybutyrate) responses. Women may compensate for diminished SNS activity during exercise by increased lipolytic responses.

Adult↗

PubMed2000

Effects of antecedent hypoglycemia on subsequent counterregulatory responses to exercise.

Antecedent hypoglycemia can blunt counterregulatory responses to subsequent hypoglycemia. It is uncertain, however, if prior hypoglycemia can blunt counterregulatory responses to other physiologic stresses. The aim of this study, therefore, was to determine whether antecedent hypoglycemia attenuates subsequent neuroendocrine and metabolic responses to exercise. Sixteen lean, healthy adults (eight men and eight women, ages 28+/-2 years, BMI 22+/-1 kg/m2, VO2max 43+/-3 ml x kg(-1) x min(-1)) were studied during 2-day protocols on two randomized occasions separated by 2 months. On day 1, subjects underwent morning and afternoon 2-h hyperinsulinemic (528+/-30 pmol/l) glucose clamp studies of 5.3+/-0.1 mmol/l (euglycemic control) or 2.9+/-0.1 mmol/l (hypoglycemic study). On day 2, subjects underwent 90 min of exercise on a static cycle ergometer at 80% of their anaerobic threshold (approximately 50% VO2max). Glycemia was equated during day 2 exercise studies via an exogenous glucose infusion. Day 1 hypoglycemia had significant effects on neuroendocrine and metabolic responses during day 2 exercise. The usual exercise-induced reduction in insulin, together with elevations of plasma epinephrine, norepinephrine, glucagon, growth hormone, pancreatic polypeptide, and cortisol levels, was significantly blunted after day 1 hypoglycemia (P<0.01). Commensurate with reduced neuroendocrine responses, key metabolic counterregulatory mechanisms of endogenous glucose production (EGP), lipolytic responses, and ketogenesis were also significantly attenuated (P<0.01) after day 1 hypoglycemia. Significantly greater rates of glucose infusion were required to maintain euglycemia during exercise after day 1 hypoglycemia compared with day 1 euglycemia (8.8+/-2.2 vs. 0.6+/-0.6 micromol x kg(-1) x min(-1); P<0.01). During the first 30 min of exercise, day 1 hypoglycemia had little effect on EGP, but during the latter 60 min of exercise, day 1 hypoglycemia was associated with a progressively smaller increase in EGP compared with day 1 euglycemia. Thus, by 90 min, the entire exercise-induced increment in EGP (8.8+/-1.1 micromol x kg(-1) x min(-1)) was abolished by day 1 hypoglycemia. We conclude that 1) antecedent hypoglycemia results in significant blunting of essential neuroendocrine (glucagon, insulin, catecholamines) and metabolic (endogenous glucose production, lipolysis, ketogenesis) responses to exercise; 2) antecedent hypoglycemia may play a role in the pathogenesis of exercise-related hypoglycemia in type 1 diabetic patients; and 3) antecedent hypoglycemia can blunt counterregulatory responses to other physiologic stresses in addition to hypoglycemia.

Adult↗

PubMed2000

Effects of differing durations of antecedent hypoglycemia on counterregulatory responses to subsequent hypoglycemia in normal humans.

The aim of this study was to determine whether the duration of antecedent hypoglycemia regulates the magnitude of subsequent counterregulatory failure. A total of 31 lean healthy overnight-fasted individuals (16 men/15 women) were studied. There were 15 subjects (8 men/7 women) who underwent two separate 2-day randomized experiments separated by at least 2 months. On day 1, 2-h hyperinsulinemic (9 pmol x kg(-1) x min(-1)) euglycemic (5.2 +/- 0.1 mmol/l) or hypoglycemic (2.9 +/- 0.1 mmol/l) glucose clamps (prolonged hypoglycemia) were carried out in the morning and afternoon. Of the other subjects, 16 participated in a 2-day study in which day 1 consisted of morning and afternoon short-duration hypoglycemia experiments (hypoglycemic nadir of 2.9 +/- 0.1 mmol for 5 min), and 10 of these individuals underwent an additional 2-day study in which day 1 consisted of morning and afternoon intermediate-duration hypoglycemia (hypoglycemic nadir of 2.9 +/- 0.1 mmol for 30 min). The next morning (day 2) all subjects underwent an additional 2-h hyperinsulinemic-hypoglycemic clamp (2.9 +/- 0.1 mmol/l). The rate of fall of glucose (0.07 mmol/min) was carefully controlled during all hypoglycemic studies so that the glucose nadir was reached at 30 min. Despite equivalent day 2 plasma glucose and insulin levels, there were significant differences in counterregulatory physiological responses. Steady-state epinephrine, glucagon, growth hormone, cortisol, and pancreatic polypeptide levels were similarly significantly blunted (P < 0.01) by the differing duration day 1 hypoglycemia compared with day 1 euglycemia. Muscle sympathetic nerve activity and endogenous glucose production were also similarly blunted (P < 0.01) by day 1 hypoglycemia (relative to day 1 euglycemia). Day 2 hypoglycemic symptoms were significantly reduced (P < 0.01) after day 1 prolonged intermediate- but not short-duration hypoglycemia. In summary, two episodes of short-duration moderate hypoglycemia can produce significant blunting of key neuroendocrine and metabolic counterregulatory responses. Hypoglycemic symptom scores are reduced by prolonged but not short-duration prior hypoglycemia. We conclude that in healthy overnight fasted humans, 1) neuroendocrine, autonomic nervous system, and metabolic counterregulatory responses are sensitive to the blunting effects of even short-duration prior hypoglycemia, and 2) the duration of antecedent hypoglycemia results in a hierarchy of blunted physiological responses with hypoglycemic symptom awareness less vulnerable than neuroendocrine responses.

Adult↗

PubMed2000

Development of CPR security using impact analysis.

The HIPAA regulations will require that institutions ensure the prevention of unauthorized access to electronically stored or transmitted patient records. This paper discusses a process for analyzing the impact of security mechanisms on users of computerized patient records through "behind the scenes" electronic access audits. In this way, those impacts can be assessed and refined to an acceptable standard prior to implementation. Through an iterative process of design and evaluation, we develop security algorithms that will protect electronic health information from improper access, alteration or loss, while minimally affecting the flow of work of the user population as a whole.

Algorithms↗

PubMed1999

Predicting community reintegration after spinal cord injury from demographic and injury characteristics.

OBJECTIVE: To determine the influence of demographic and injury characteristics on the community reintegration of people with spinal cord injury (SCI). DESIGN: Prospective cross-sectional and longitudinal examination of individuals with SCI. SETTING: Follow-up of individuals at 1, 2, 5, 10, 15, and 20 years after SCI who received their initial rehabilitation in a Regional Model Spinal Cord Injury System. PARTICIPANTS: A total of 3,835 individuals who met the inclusion criteria for the National SCI Database were studied cross-sectionally, and a subset of 347 individuals who were also enrolled in a longitudinal study of aging with SCI. MAIN OUTCOME MEASURES: Subscales of the Craig Handicap Assessment and Reporting Technique (CHART). RESULTS: Neurologic classification, age, years postinjury, gender, ethnicity, and education explain 29% of the variance in physical independence, 29% of the variance in mobility, 28% of the variance in occupation. 9% of the variance in social integration, and 18% of the variance in economic self-sufficiency. CONCLUSIONS: Although these factors are inadequate to explain most of the variation in community reintegration (handicap) after SCI, they might appropriately be used to adjust for case-mix differences when comparing rehabilitation facilities and techniques.

Activities of Daily Living↗

PubMed1999

Access to the environment and life satisfaction after spinal cord injury.

OBJECTIVE: To determine the potential relation between satisfaction with life after spinal cord injury and access to the environment as measured by selected items from the Craig Handicap Assessment and Reporting Technique (CHART). DESIGN: Prospective, correlational/predictive study using cross-sectional and longitudinal data from 18 Model Spinal Cord Injury Systems of Care. SUBJECTS: Adult persons with traumatic-onset spinal cord injury (n = 650) evaluated at 1 or 2 years postinjury. OUTCOME MEASURE: Satisfaction With Life Scale (SWLS). PREDICTOR VARIABLES: Demographic characteristics, impairment and disability classifications. medical complications, rehabilitation insurance status, occupational status as measured by the CHART Occupation Scale, self-perceived health (from SF-36), and access to the environment as measured by items from the CHART Mobility Scale. RESULTS: Access to the environment was positively and linearly associated with satisfaction with life, demonstrated both positive and negative change over time, and was positively associated with subject's neurologic status. Access to the environment added to the explanatory model to predict life satisfaction even after all other independent measures were accounted for. CONCLUSION: Access to the environment (an "outside the person" factor) is important in predicting satisfaction with life for persons with spinal cord injury. The measure of access to the environment developed here is promising and worthy of further exploration and expansion.

Activities of Daily Living↗

PubMed1998

Serum distemper virus and parvovirus antibody titers among dogs brought to a veterinary hospital for revaccination.

OBJECTIVE: To determine serum canine distemper virus (CDV) and canine parvovirus (CPV) antibody titers in healthy dogs brought to a veterinary hospital for revaccination. DESIGN: Case series. ANIMALS: 122 dogs. PROCEDURE: Serum antibody titers were measured by means of hemagglutination inhibition (CPV titers) or serum neutralization (CDV titers) at the time dogs were brought to the hospital for revaccination. All dogs had been vaccinated between 271 and 1,665 days previously. Dogs were grouped by age, breed (purebred vs mixed breed), sex, and weight to determine whether these factors were associated with antibody titers. Serum CPV titers > or = 1:80 and serum CDV titers > or = 1:96 were considered protective. RESULTS: Breed, sex, and weight were not significantly associated with serum CPV and CDV titers. Age was significantly associated with CPV titer, with younger dogs having higher titers, but was not associated with CDV titer. Thirty-three of 122 (27%; 95% confidence interval, 19.0 to 34.9%) dogs had a less-than-protective CPV titer. Twenty-five of 117 (21%; 95% confidence interval, 13.6 to 28.4%) dogs had a less-than-protective CDV titer. CLINICAL IMPLICATIONS: Results suggest that, on the basis of serum antibody titers, the current practice of annual revaccination of dogs against CPV and CDV infection should be maintained. Measurement of antibody titers to determine whether revaccination is truly needed would seem justifiable in those dogs that have previously had an adverse reaction to vaccination.

Age Factors↗