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Biomedical subjects

B Wood

Publications and source records attributed to B Wood.

At least 109 records · Page 6Linked to original sources
PubMed1991

Effects of hypoxia on fetal rat brain metabolism studied in utero by 31P-NMR spectroscopy.

An animal model of perinatal asphyxia, in which near-term fetal rats are subjected to-short periods of hypoxia, has been investigated by 31P-NMR spectroscopy. Changes in the high-energy phosphates and intracellular pH of the fetal rat brain were measured in utero following ligation of the placental blood vessels, and during reperfusion after a 20-min period of occlusion. The hypoxia-induced changes observed in the fetal brain were substantially slower than in the adult, and were completely reversible after 20 min of hypoxia.

Adenosine Triphosphate↗
PubMed1991

Normalization of left ventricular ejection fraction following resection of pheochromocytoma in a patient with dilated cardiomyopathy.

Catecholamine-induced cardiomyopathy associated with pheochromocytoma is a well-recognized but rare entity. Both hypertrophic and dilated variants have been described. We report a case of dilated cardiomyopathy associated with a benign pheochromocytoma that showed complete normalization of left ventricular systolic function following removal of the tumor. Serum noradrenaline and dopamine were significantly elevated without elevation in serum adrenaline levels. This may be the first report in which radionuclide ventriculography was used to document the time course of normalization in LVEF following removal of a pheochromocytoma.

Adolescent↗
PubMed1990

Radiographic followup of joints injected with triamcinolone hexacetonide for the management of childhood arthritis.

Evidence of deleterious effects following intraarticular injection of triamcinolone hexacetonide was sought through a review of radiographs of 145 joints of 55 children with chronic arthritis. Possible deleterious effects were noted in 16 joints of 11 patients. These effects included: small patella (2 joints), patellar osteochondritis dissecans (1 joint), periarticular calcification (9 joints), intraarticular tibial bony spur (1 joint), avascular necrosis of the distal radial epiphysis (2 joints), and avascular necrosis of the proximal femoral epiphysis (1 joint). Only the latter possible complication was symptomatic. Serial radiographs of 76 joints of 30 children showed mild progressive changes compatible with the underlying disease, except in the hip joint, where changes were more severe. The intraarticular injection of triamcinolone hexacetonide is a procedure that appears to be associated with an acceptably low frequency of radiologic abnormalities for many joints in children with chronic arthritis, but its effects on the hip joint remain uncertain.

Anti-Inflammatory Agents↗
PubMed1990

Pulmonary function following positive pressure ventilation initiated immediately after birth in infants with respiratory distress syndrome.

Cardiopulmonary function following positive pressure ventilation, initiated immediately after birth, was evaluated in 10 very low birthweight infants with respiratory distress syndrome (RDS; RDS infants). Multiple gas rebreathing methodology was used to measure functional residual capacity (FRC), diffusing capacity of the lung for carbon monoxide (DLCO) and effective pulmonary capillary blood flow (Qeff) at 2, 24, and 72 hr of age. Cardiopulmonary function variables were also measured at 2 hr of age in 10 infants of similar birthweight who did not have RDS (non-RDS infants). In RDS infants, mean FRC at both 2 hr of age (15 mL/kg or 0.42 mL/cm) and 24 hours of age (20 mL/kg or 0.54 mL/cm) was less than published predicted values for healthy infants and significantly less than values in non-RDS infants at 2 hours of age (29 mL/kg or 0.8 mL/cm). By 72 hr of age, mean FRC in RDS infants rose to predicted. At 2 and 24 hours of age, mean Qeff in RDS infants (41 and 38 mL/min/kg, respectively) was below predicted, as well as below the value observed in non-RDS infants at 2 hr of age (62 mL/min/kg). in RDS infants. DLCO remained well below published predicted values throughout the first three days of life. We conclude that early aggressive respiratory therapy does not result in the establishment of normal lung volumes during the first day of life, but it does so by 3 days of age. However, in spite of intubation immediately after birth and the application of continuous positive pressure ventilation during the first 3 days of life, very low birthweight infants with RDS continue to have significant alteration in lung function, evidenced by impaired diffusing capacity of the lung and low arterial-alveolar oxygen tension ratios.

Functional Residual Capacity↗
PubMed1990

Early and late peritoneal dialysate leaks in patients on CAPD.

Dialysate leaks, which occurred in 386 CAPD patients over 11 years, were analyzed retrospectively. 18 patients developed 21 early leaks (within 30 days of catheter insertion) and 18 patients developed 28 late leaks (beyond 30 days of catheter insertion). 8 patients had multiple (2-6) leaks. Both early and late leaks, particularly if they were multiple, were associated with conditions that affect adversely tissue healing and tensile strength. Median surgical insertion was apparently associated with a higher incidence of early leaks. Early leaks were manifested externally, usually through the exit site, and did not require imaging. Late leaks were manifested usually by poor dialysate outflow, localized edema and subcutaneous fluid collections. One third of the late leaks required radiological imaging. Hernias caused 42% of the late leaks. Early leaks were managed by temporary discontinuation of CAPD alone (57%) or surgery. Most late leaks (67%) required surgery. Conservative means (change to IPD, observation) were applied for the management of a few late leaks. Both early and late leaks resulted frequently in replacement of peritoneal catheters, but only late leaks resulted in permanent discontinuation of peritoneal dialysis. Paramedian surgical insertion, waiting period of 10-14 days between catheter insertion and initiation of CAPD, and low starting dialysate volumes have resulted in apparent reduction of the incidence of the early, but not of the late leaks. Dialysate leaks have serious consequences on the performance of CAPD. Early leaks differ from late leaks in some clinical manifestations. Preventive measures have decreased the incidence of early, but not of the late leaks.

Catheters, Indwelling↗
PubMed1989

Psoriatic arthritis in children.

A proposed definition of juvenile psoriatic arthritis (JPsA) was used to identify definite or probable JPsA in 35 children. Definite JPsA (24 patients) was defined as arthritis associated, but not necessarily coincident, with a typical psoriatic rash, or arthritis plus at least 3 of 4 minor criteria: dactylitis, nail pitting, psoriasis-like rash, or family history of psoriasis. Probable JPsA (11 patients) was defined as arthritis plus 2 of the minor criteria. In 33 of 35 patients, the onset of arthritis was pauciarticular, but the disease followed a polyarticular course in 23 of 35. Chronic anterior uveitis (6 of 35), antinuclear antibodies (22 of 35), anticollagen antibodies (10 of 35), HLA-DR4 (2 of 28), and HLA-DR8 (5 of 28) occurred with frequencies similar to those seen in patients with juvenile rheumatoid arthritis. JPsA may have more in common with juvenile rheumatoid arthritis than with the seronegative spondylarthropathies with which it is traditionally associated.

Adolescent↗
PubMed1989

In vivo magnetic resonance imaging of the effects of photodynamic therapy.

Nuclear magnetic resonance (NMR) proton imaging and measurements of the parameters T1 and T2, have been carried out in vivo on the murine mammary tumour T50/80. Tumours had been treated 24 h previously by photodynamic therapy (PDT, using haematoporphyrin derivative and 630 nm laser light). Proton images clearly demarcated a high signal-intensity region on the side of the tumour closest to the incident light beam, while the parts of the tumour more remote from the beam resembled the images from untreated controls. Both T1 and T2 values were raised in the high-intensity region. This high-intensity region was shown to correspond to PDT-induced histological necrosis, the low-intensity region to histologically intact tumour. Linear regression analysis of the relationship of depth of necrosis measured histologically and 'depth of necrosis' measured from the NMR images, yielded a slope of 0.93 (r2 = 0.95).

Animals↗
PubMed1989

The effect of pregnancy in humans on the pharmacokinetics of stable isotope labelled phenytoin.

1. To investigate the mechanism of the fall in steady-state plasma phenytoin concentration relative to drug dose that occurs during pregnancy, single dose pharmacokinetic studies with stable isotope labelled phenytoin were carried out at different stages of pregnancy, and 2 to 4 months post-natally, in five epileptic women receiving regular oral therapy with the drug. 2. Steady-state apparent plasma clearances of phenytoin (dose/steady-state concentration) correlated closely with simultaneous plasma clearances of the intravenous stable-isotope drug (measured as dose/AUC) suggesting that the patients were complaint with therapy when their phenytoin dosage requirement increased during the pregnancy, and that the oral drug was fully bioavailable. 3. In retrospect, two of the five subjects were probably studied too early post-natally for phenytoin elimination kinetics to have returned to non-pregnant values. Despite this, (i) the mean +/- s.d. t 1/2 for phenytoin was statistically significantly shorter in pregnancy than post-natally (31 +/- 14 vs 39 +/- 28 h), (ii) the mean +/- s.d. whole plasma clearance was also statistically significant greater (0.025 +/- 0.012 vs 0.021 +/- 0.013 kg-1 h-1) and (iii) the mean +/- s.d. Vmax for phenytoin elimination was statistically significantly greater in pregnancy (1170 +/- 600 mg day-1) than post-natally (780 +/- 470 mg day-1). Although the mean +/- s.d. apparent Km was higher in pregnancy (18.2 +/- 8.4 mg l-1, expressed in terms of whole plasma drug concentrations, compared with 10.2 +/- 7.4 mg l-1 post-natally), the difference was not statistically significant. However, if the apparent Km value was expressed in terms of plasma water phenytoin concentrations the difference (pregnant 2.50 +/- 0.85 mg l-1: post-natally 1.16 +/- 0.65 mg l-1) was statistically significant. 4. Human pregnancy appears to result in an increased capacity to eliminate phenytoin.

Adult↗
PubMed1989

The "psychosomatic family" model: an empirical and theoretical analysis.

Evolution of the Family Systems Paradigm has been constrained by the dichotomy between theory building and empirical research. This article integrates these two domains by presenting a theoretical analysis of the "psychosomatic family" model as it informs and is informed by an empirical research project. Forty families of children with Crohn's disease (CD), ulcerative colitis (UC), and functional recurrent abdominal pain syndrome (RAP) were rated during standard, videotaped family interaction tasks, lunch, and interview. Laboratory scores of disease activity were associated with triangulation, marital dysfunction, and total "psychosomatic family" scores. Disease activity was not significantly correlated with enmeshment, overprotection, rigidity, conflict avoidance, or poor conflict resolution. Thus, the marital/triangulation and enmeshment/overprotection/conflict clusters may be subcomplexes of the "psychosomatic family" complex. CD, UC, and RAP groups differed in the relations among particular family patterns and disease activity. A heuristic family-psycho-somatic model is presented to facilitate future research.

Abdominal Pain↗
PubMed1989

Survival and morbidity of extremely premature infants based on obstetric assessment of gestational age.

To provide current clinical information for obstetric decision-making and perinatal management, we present early morbidity and mortality data for extremely premature infants based on obstetric assessment of gestational age. We reviewed the records of 141 live-born infants with birth weights of 1600 g or lower born at a university hospital level III neonatal intensive care unit between January 1986 and April 1988, whose gestational ages estimated by antenatal obstetric evaluation were between 24-29 completed weeks. Neonatal survival to 30 days ranged from 20% at 24 weeks to 94% at 29 weeks. Chronic lung disease was present at 30 days in all infants born at 24 weeks' gestation, decreasing to 13% of infants born at 29 weeks' gestation. Rates of severe intraventricular hemorrhage (grade 3 or 4) ranged from 100% at 24 weeks to 7% at 29 weeks. These data represent a significant increase in survival and a decrease in early morbidity compared with those form similar populations before 1986.

Birth Weight↗
PubMed1989

Do artificial limbs become part of the user? New evidence.

This paper provides evidence that limb-deficient subjects who wear artificial arms tend to overestimate the perceived length of their residual limb. It is proposed that this "perceptual error" may provide a useful and possibly more valid alternative to existing methods of determining prosthetic acceptance. The degree of overestimation is substantial for most subjects with amputations, and typically represents 20 percent of the length of the prosthetic arm. The effect is considerably reduced when the prosthetic limb is removed. Comparisons are made with normal-limbed subjects of various ages. For the most part, their errors are small and typically are underestimates of actual limb length. This research is compared with the work of Fraser (1984), who found similarities in reaching trajectories for normal and artificial arms. Further investigation is required to determine if this effect may serve as an index of adjustment to a prosthesis and, additionally, if prosthetics training programs might benefit from including techniques for enhancing perceptual adaptations to artificial limbs.

Adaptation, Psychological↗