In search of cooperation.
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Cooperative Behavior↗
Biomedical subjects
D Hastings
Publications and source records attributed to D Hastings.
CPAP. A supportive adjunct for congestive heart failure in the prehospital setting.
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Airway Resistance↗
Patient, visitor, and nurse evaluations of visitation for adult postanesthesia care unit patients.
Although PACU visitation for children is sometimes encouraged, most families of adult postoperative patients continue to be excluded from PACUs in this country. At an academic medical center, an open visitation policy for adult postoperative patients was evaluated by eliciting patient, visitor, and nurse evaluations of visitation for adult patients from 181 families. Commonly cited reasons for restricting PACU visitation were not identified as problems by the vast majority of respondents. Even when some aspect of a PACU visit was disturbing, patients and families expressed a desire for visitation. The results of this evaluation of a change in practice led to permanent implementation of an open visitation policy in this PACU.
Adult↗
Responses to chronic hypoxia in embryonic alligators.
To investigate developmental responses to chronic hypoxia, we incubated alligator eggs at 17% O2 and 21% O2 for the entire course of embryonic development and for 5 months post-hatching. Hypoxic-incubated alligators hatched later and at a smaller size. Hematocrit was significantly higher in hypoxic-incubated animals immediately post-hatch. Allosteric modification of hemoglobin oxygen affinity did not appear to play a role in the adaptation to hypoxia, given equal nucleotide triphosphate-to-hemoglobin ratios in the hypoxic and normoxic groups. When acutely exposed to 21% O2, hypoxic-incubated alligators maintained oxygen consumption relative to their normoxic siblings despite their lower mass.
Alligators and Crocodiles↗
Developmental changes in oxygen consumption regulation in larvae of the South African clawed frog Xenopus laevis
Well-developed larval Xenopus laevis (NF stages 58­66) are oxygen regulators, at least during mild hypoxia. When and how they change from oxygen conformers (the presumed condition of the fertilized egg) to oxygen regulators is unknown. Also unknown is how anaerobic metabolic capabilities change during development, especially in response to acute hypoxia, and to what extent, if any, anaerobiosis is used to supplement aerobic metabolism. Consequently, we have investigated resting rates of oxygen consumption (M.O2) and concentrations of whole-body lactate (lactic acid) during development in normoxia and in response to acute hypoxia in Xenopus laevis. M.O2 increased in an episodic, non-linear fashion during development. Resting, normoxic M.O2 increased about tenfold (to approximately 0.20 µmol g-1 h-1) between NF stages 1­39 and 40­44, and then another tenfold between NF stages 45­48 and 49­51 (to approximately 2.0 µmol g-1 h-1), remaining at about 2 µmol g-1 h-1 for the remainder of larval development. M.O2 reached its highest level in newly metamorphosed frogs (nearly 4 µmol g-1 h-1), before decreasing to about 1.0 µmol g-1 h-1 in large adults. X. laevis embryos and larvae up to NF stage 54­57 were oxygen conformers when exposed to variable levels of acute hypoxia. The only exception was NF stage 45­48 (external gills present yet body mass still very small), which showed some capability of oxygen regulation. All larvae older than stage 54­57 and adults were oxygen regulators and had the lowest values of Pcrit (the oxygen partial pressure at which M.O2 begins to decline). Whole-body lactate concentration in normoxia was about 1 µmol g-1 for all larval groups, rising to about 12 µmol g-1 in adults. Concentrations of lactic acid in NF stages 1­51 were unaffected by even severe ambient hypoxia. However, whole-body lactate levels in NF stages 52­66 increased in response to severe hypoxia, indicating that some anaerobic metabolism was being used to supplement diminishing aerobic metabolism. The largest increases in concentration of lactate occurred in late larvae and adults.
Journal Article↗
Scintigraphic evaluation of sialadenitis.
Salivary gland scintigraphy using 99Tcm sodium pertechnetate and a 20-min dynamic data acquisition with a sialogogue at 10 min was employed as the primary imaging modality in sialadenitis in 32 patients. Paired asymptomatic glands within the study group were used to establish control values for a number of computer-derived functional parameters. The shape of the activity-time curve was described as: H = hyperactive, N = normal, M = median, S = sloped, F = flat, O = obstructed. Of seven patients who had ductal stones on plain films, two passed stones prior to sialography and had normal curves, whole the remaining five patients had Type O curves. Parametric evidence of gland dysfunction was identified in an additional seven symptomatic glands, six being hyperactive; histology identified an acute inflammatory infiltrate in the only excised gland in this group. Glandular hypofunction was identified in one case, in which histology revealed extensive fibrosis and glandular atrophy. Type M and S curves were found in 28 glands, 75% of which were asymptomatic. Only one gland was indicated as hypoactive by calculated parameters, and this showed a Type S curve. Scintigraphy and plain films represent the least invasive and, we feel, the most suitable primary method of investigating sialadenitis. Conventional contrast sialography may be reserved for cases with no identifiable stone but an obstructed curve. The use of functional parameters and curve morphology to determine gland dysfunction other than obstruction is non-specific, probably insensitive and is unlikely to alter clinical management. We propose an algorithm for the investigation of sialadenitis.
Adolescent↗
Reliability of assessing patellar alignment: the A angle.
Anterior knee pain syndrome is a complex problem for clinicians and patients. One possible etiological factor that has been identified is malalignment of the patella. Recently, a clinical method to assess patellar malalignment has been proposed--the A angle. However, no reliability of this technique was reported. Therefore, the purpose of this study was to determine intrarater and interrater reliability for the A angle. Thirty-six subjects participated in this study. Three raters measured each knee twice (N = 70). Interclass correlation coefficients (ICC) and standard error of measurements (SEM) were determined for the A angle and component measurements. Intrarater A-angle values ranged from 11.8 to 23.5 degrees. Intrarater A-angle ICCs were poor (0.20-0.32, SEM = 5.30-7.95 degrees). Interrater A-angle ICC was poor (-0.01, SEM = 7.82 degrees). Results indicated that the A angle as determined in this study was not reproducible. Therefore, further study is needed before the A angle can be used as a reliable assessment tool for patellar position.
Adult↗
Failure of internal fixation of displaced femoral neck fractures in rheumatoid patients.
We reviewed the records and radiographs from 10 hospitals to identify 50 patients with rheumatoid arthritis (RA) who had sustained 52 femoral neck fractures. Most patients were female (88%), elderly (mean age 66 years) and had had severe polyarticular disease for a mean duration of 16 years. Over half had taken systemic corticosteroids, nearly all were severely osteopenic but few had rheumatoid changes in the hip. Of the 20 fractures treated by internal fixation 12 had complications including nonunion (5), osteonecrosis (5), infection (1), and intertrochanteric fracture (1). Only one of the nine undisplaced fractures required reoperation, but seven of the 11 displaced fractures had revision surgery. Twenty fractures were treated by primary total hip arthroplasty with only one early complication. The other 12 fractures had been treated by hemiarthroplasty (9), hip excision (1) or non-operatively (2). Our results suggest that, in elderly rheumatoid patients, severely displaced femoral neck fractures should be treated by total hip replacement.
Adult↗
Pulmonary hemorrhage in an immunocompromised, thrombocytopenic patient. How to make a difficult diagnosis.
Bilateral, diffuse infiltrates visible on chest radiographs of an immunocompromised patient suggest the possibility of infection, but occasionally other interesting conditions are responsible for the clinical picture. In this article, the authors describe a case in which special procedures were necessary to make the correct diagnosis.
Anemia, Aplastic↗
Growth and detection of human bone marrow B-lineage colonies.
A reproducible method for growing normal human bone marrow B-lineage colonies in agar is described. The clonogenic cells require a rich medium, Opti-MEM (GIBCO/BRL, Burlington, Ontario, Canada), and a source of T-cell-derived factors for growth. The conditions described appear to be limiting for the colony progenitor, suggesting assay clonality. Three novel methods that permit routine and rapid detection of these human B-cell colonies are also described. Colonies containing cells that secrete immunoglobulin are detected by plaquing and protein immunoblotting, while RNA transcripts can be detected by RNA colony blotting. The detection of more than one secreted immunoglobulin isotype or RNA species in a single colony can also be achieved. This B-cell colony assay and the associated detection methods will allow the further delineation of human B lymphopoiesis in both normal and disease states.
B-Lymphocytes↗
Supracondylar fractures of the femur adjacent to resurfacing and MacIntosh arthroplasties of the knee in patients with rheumatoid arthritis.
Twelve cases of supracondylar fracture of the femur in rheumatoid arthritis patients with previously implanted resurfacing or MacIntosh arthroplasty of the knee had long standing severe polyarticular rheumatoid arthritis (duration, ten to 41 years; mean 24.8 years). The fractures occurred following a long interval after implantation of the prosthesis (five to 204 months; mean, 92.3 months). Two fractures were treated by stable and two by unstable fixation; eight were treated nonoperatively. The fractures healed in a normal time with one exception, but the femur was shortened in ten cases (mean, 2.8 cm), and axially malaligned in nine. The ability to walk long distances decreased in eight cases and pain increased in seven; two prostheses were loosened and displaced. Because of the poor results of nonoperative management, internal fixation of these fractures is recommended in selected cases.
Adult↗
Congenital heart disease in pregnancy: short- and long-term implications.
One hundred forty-four pregnancies that occurred in 74 patients with congenital heart disease at the Toronto General Hospital between 1975 and 1986 were reviewed. The patients were divided into two groups, those with acyanotic lesions and those with cyanotic lesions. Maternal and fetal outcomes in these two groups were compared. Patients with cyanotic lesions developed significantly more congestive heart failure and deteriorated more often in functional cardiac status than those with acyanotic lesions (p less than 0.005). Women with obstructive lesions had a higher incidence of pregnancy-induced hypertension than our general population (p less than 0.005). There was one maternal death in the puerperium in a woman with Eisenmenger's syndrome. Preterm births were more frequent in the cyanotic group (p less than 0.01) as were small for gestational age infants (p less than 0.005). In the cyanotic group the mean birth weight was 900 gm less than that in the acyanotic group (p less than 0.005). The major benefits of corrective cardiac surgery were in the cyanotic group and consisted of fewer spontaneous abortions (p less than 0.01) and small for gestational age infants (p less than 0.02) and more term births (p less than 0.01). Long-term follow-up revealed that 19.2% of women with acyanotic lesions had significant cardiac developments, compared with 90% in the cyanotic group (p less than 0.005). One of 87 infants (1.1%) had congenital heart disease and two had Marfan's syndrome.
Female↗
Ganglion of the ankle.
Ganglia rarely occur on the ankle. We report a case of a ganglion on the medial malleolus, originating from the sheaths of the flexor digitorum longus and tibialis posterior tendons, which posed a diagnostic dilemma for the patient's family physician, for her dermatologist, and for the orthopedic surgeon seen in consultation. Ganglia should be considered in the differential diagnosis of all periarticular cystic lesions.
Ankle↗
Virus-like filamentous intranuclear inclusions in a giant-cell tumor, not associated with Paget's disease of bone. A case report.
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Adult↗
Unusual metastatic patterns of prostate adenocarcinoma.
While prostatic adenocarcinoma is associated classically with osseous or lymphatic metastasis, it can present clinically with protean manifestations. We describe 4 cases that demonstrate unusual patterns of metastatic spread, including isolated supraclavicular mass, pleural effusion, suprapubic and genital skin metastasis, and priapism. Newer immunohistochemical staining techniques for prostate specific antigen and prostatic acid phosphatase can assist in localization of the metastatic adenocarcinoma to a prostatic origin.
Acid Phosphatase↗
Revision of total hip arthroplasty.
Between September 1978 and December 1980, 28 revision procedures were carried out at the Wellesley Hospital, Toronto, for biomechanical failure of total hip arthroplasties. Twenty-six patients were personally reviewed and assigned a Harris hip rating. Seven patients had major complications intraoperatively or postoperatively; three of them required further surgery. Twenty-four patients had satisfactory results and none were worse. The mean Harris score preoperatively was 36.3. At a minimum follow-up of 1 year after revision, the mean Harris score rose to 79.9 (p less than 0.01). Revision of total hip arthroplasty is a difficult and demanding procedure but can produce satisfactory results.
Adult↗
Weak acid permeability through lipid bilayer membranes. Role of chemical reactions in the unstirred layer.
The premeabilities of planar lipid bilayer (egg phosphatidylcholine-decane) membranes to butyric and formic acids were measured by tracer and pH electrode techniques. The purposes of the study were (a) to establish criteria for the applicability of each method and (b) to resolve a discrepancy between previously published permeabilities determined using the different techniques. Tracer fluxes of butyric acid were measured at several concentrations and pH's. Under symmetrical conditions the one-way flux of butyric acid(J) is described by 1/J = 1/Pul ([HA] + [A-]) + 1/Pm([HA]), where Pul and Pm are the unstirred layer and membrane permeability coefficients. Pm determined in this manner is 950 x 10(4) cm s-1. Published values for the butyric acid permeability for egg phosphatidylcholine-decane bilayers are 11.5 x 10(-4) (Wolosin and Ginsburg, 1975) and 640 x 10(-4) cm s-1 (Orbach and Finkelstein, 1980). Wolosin and Ginsburg measured net fluxes from a solution of pH = Pka into an unbuffered solution containing a pH electrode. Orbach and Finkelstein measured tracers fluxes under symmetrical conditions at pH 7.4. We reproduced the results of Wolosin and Ginsburg and showed that their apparently low Pm was caused by unstirred layer effects in their poorly buffered solutions. The permeability to formic acid (pKa = 3.75) measured by both tracer and pH electrode techniques was approximately 10(-2) cm s-1. However, if pm greater than Pul, the pH electrode technique cannot be used for measuring the permeabilities of weak acids with pKa's greater than approximately 4.
Alkanes↗
Potassium binding to the (Na+ + K+)-ATPase.
The number of K+ bound to the (Na+ + K+)-ATPase has been measured under equilibrium conditions by a differential-titration technique (Hastings, D.F. (1977) Anal. Biochem. 83, 416-432). 5.1 K+ were bound per 32P-labelling site. The K'D for K+ was dependent on the concentration of choline, which was included to give ionic strength. K'D was 59 +/- 2.5 microM with 97 mM choline, 26 +/-1.9 microM with 30 mM choline. The K+ : choline selectivity was 2564 : 1 and the calculated K'D for K+ with zero choline was 11 microM and for choline with zero K+ was 28 mM. 20 microM ATP in the presence of 97 mM choline incresed the K'D for potassium 3-fold to 177 +/- 14 microM. The K'D for K+ with 3 mM Na+ in the presence of 27 mM choline was 81 +/- 10 microM and with 30 mM Na+ without choline 700 +/- 250 microM. The calculated K'D for Na+ at zero K+ and zero choline was 0.6 +/- 0.2 mM. The K+ : Na+ selectivity was 54 : 1.
Animals↗