Biomedical subjects
Publications and source records attributed to R Hawkins.
The existence of cyclical (circadian) variations in lithium toxicity in mice was determined. Mice, standardized to a light-dark cycle, were injected with lithium chloride (940 mg/kg) at one of six times (20:00, 24:00, 4:00, 8:00, 12:00, and 16:00) and subsequently observed for mortality over 28 h. A significant (P less than 0.01) time-of-day effect was found for lithium-induced lethality, with highest lethality following injection at 12:00.
This report outlines the clinical and physiological features in 50 asthmatic patients with chronic allergic bronchopulmonary aspergillosis in whom the diagnosis was made from 2 to 25 years ago (mean duration 10-9 years). From a questionnaire and analysis of the peak expiratory flow rate measurements it was found that they were worse in the winter months, corresponding to the maximal concentrations of Aspergillus fumigatus in the atmosphere. Nineteen patients reported daily sputum production of up to an eggcupful or more, and 24 had noticed sputum 'plugs' in the previous year. Reduction of vital capacity (VC) was found in 20 patients, of forced expiratory volume in one second (FEV1) in 38 patients, and of maximal expiratory flow at 50% VC breathing air (V50air) in 47 patients. Nine patients had significantly reduced gas transfer factor (DLCO). Significant improvement (more than 15%) in FEV1 after inhaled bronchodilator was shown by only 17 patients. There were statistically significant correlations between the degree of reduction in the physiological measurements of VC, FEV1, and V50air with the age of the patient at the time of the study and the later in life the diagnosis of aspergillosis was made, whereas the reduction in DLCO was also significantly related to the duration of aspergillosis. Prospective studies are needed for a proper assessment of any protective effect of treatment on the pathophysiological changes due to the disease over many years.
Precipitin tests by two different methods, double-diffusion (DD) and counterimmunoelectrophoresis (CIE), and measurements of total and specific IgE against Aspergillus fumigatus were made in 50 patients with chronic allergic bronchopulmonary aspergillosis and in three control groups--atopics with a positive immediate prick test to A. fumigatus but no evidence of allergic aspergillosis, atopics with a negative prick test to A. fumigatus, and non-atopics. Precipitins were found in 84% and 78% of the patients with aspergillosis by the DD and CIE methods respectively. Precipitins were also found in 6 out of 27 (22%) patients with a positive prick test to A. fumigatus but no evidence of aspergillosis and in 1 of 24 patients with a negative prick test to A. fumigatus. The means of specific and total IgE values were significantly higher in the group of patients with aspergillosis than in the three other groups of patients. The increase in specific but not total IgE showed a statistically significant correlation with positive precipitin tests in the patients with aspergillosis. Total IgE but not specific IgE values were significantly higher (0-02 less than P less than 0-05) in patients who had had a transient radiographic shadow in the previous three months. Positive precipitin tests were also significantly correlated with the number of transient shadows in the past and with the interval of time since the last transient shadow.
A comparison is made of lung function tests and radiographic findings in 20 asthmatic patients with allergic bronchopulmonary aspergillosis paired in terms of sex, age, and duration of asthma with 20 other asthmatics in whom the diagnosis of aspergillosis was excluded in order to see if the aspergillosis causes more lung damage. One hundred per cent of the patients with aspergillosis and 75% of the patients with asthma alone showed a significantly reduced forced expiratory volume in one second (FEV1) before bronchodilator. All the patients in the two groups had a significantly reduced maximal expiratory flow at 50% vital capacity breathing air (V50air) but the severity of the reduction was statistically greater in the aspergillosis group. Reversibility in FEV1 of 15% and more was found in 50% of patients with asthma alone as against 31% of patients with aspergillosis. The degree of reversibility of FEV1 was also statistically greater in patients with asthma alone. Improvement of less than 20% of V50 after helium-oxygen breathing was found in 33% of the patients with asthma alone and in 75% of the patients with aspergillosis. Patients with aspergillosis also showed significantly (0-001 less than P less than 0-01) more reduced gas transfer factor. Radiological features of overinflation were as common in the two groups. Tubular and ring shadows were found in 95% and 60% respectively of patients with aspergillosis as against 45% and 15% of patients with asthma alone.
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Concentrations of chorionic somatomammotrophin (hCS) in maternal plasma at the time of delivery and in placental extracts were determined by radioimmunoassay and related to neonatal growth in 111 normal pregnancies. Mean maternal plasma hCS concentration was lower in association with small-for-dates infants, defined by either height or weight, than with well-grown preterm or term infants. Mean placental hCS concentration was not decreased in association with undergrown infants though placental hCS was correlated with maternal hCS (r=0 - 245).
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Using an existential-phenomenological approach, this paper describes how women with breast cancer experience the giving and receiving of social support in a computer-mediated context. Women viewed their experiences with the computer-mediated support group as an additional and unique source of support in facing their illness. Anonymity within the support group fostered equalized participation and allowed women to communicate in ways that would have been more difficult in a face-to-face context. The asynchronous communication was a frustration to some participants, but some indicated that the format allowed for more thoughtful interaction. Motivations for seeking social support appeared to be a dynamic process, with a consistent progression from a position of receiving support to that of giving support. The primary benefits women received from participation in the group were communicating with other people who shared similar problems and helping others, which allowed them to change their focus from a preoccupation with their own sickness to thinking of others. Consistent with past research is the finding that women in this study expressed that social support is a multidimensional phenomenon and that their computer-mediated support group provided abundant emotional support, encouragement, and informational support. Excerpts from the phenomenological interviews are used to review and highlight key theoretical concepts from the research literatures on computer-mediated communication, social support, and the psychosocial needs of women with breast cancer.
PURPOSE: The goal of the study was to investigate the use of automated registration techniques for interpretation of volume MR and high resolution FDG-PET images that were obtained from patients with brain tumors. METHOD: Twenty-one patients with brain tumors were studied on one or more occasions using MRI and high resolution FDG-PET. The data were aligned using automated volume- and surface-matching algorithms. Composite images comprising the resliced pre- and postgadolinium spoiled GRE, T2-weighted SE, and PET data were constructed to correlate intensities of regions on the PET images with regions that corresponded to normal gray matter, white matter, and gadolinium enhancement. RESULTS: The accuracy of registration between the MR and PET images was estimated to be within 1-2 mm based upon the distance between surfaces of the outside of the head. In 12 of the 24 examinations, there were diagnoses of recurrent tumor, with only 5 of these exhibiting regions of higher FDG uptake than normal gray matter. For 19 of the 24 studies, the anatomic context provided by the registered MR images was found to be important in distinguishing recurrent tumor from necrosis based upon FDG uptake. CONCLUSION: The automated alignment was found to be an important factor in interpreting the high resolution PET images. This was particularly true for small lesions close to the cortex and for situations where FDG uptake had been reduced by prior treatment with radiation therapy.
The purpose of this study was to investigate cross-sectional and longitudinal associations between hearing acuity and tooth loss in 1156 US veterans taking part in the Veterans Affairs' Normative Aging (NAS) and Dental Longitudinal (DLS) Studies in the Boston, MA, area. The mean age was 48 years (SD = 8.9), 5.3% were edentulous, and 15.4% had < 17 teeth at baseline. Hearing acuity was determined by puretone, air- and bone-conduction audiometry, and speech discrimination tests at triennial examinations over a 20-year follow-up period. Hearing decline was defined as a change from baseline in the average puretone air-conduction thresholds of > or = 20 dB at 0.25, 0.5, 1, 2, 3, 4, 6, and 8 kHz. The explanatory variables of interest were change since baseline in dentate status (cut points at < 1, < 17, and < 20 teeth), and in the number of teeth lost (linear). Linear and logistic regression models--which controlled for baseline audiological status, age, air-bone gap, and otoscopic examination at current visit--showed that subjects who went from having > or = 17 to < 17 teeth had 1.64 times (95% CI, 1.24-2.17) as high odds of having hearing decline as those with no change in their dentate status. For every tooth lost since baseline, there was a 1.04 times as high odds (95% CI, 1.02-1.06) for hearing decline, when additional baseline and time-varying covariates were taken into account in the model.
A new technique is described for the autoradiographic determination of regional brain glucose metabolism employing 14C labeled glucose as substrate and measurement principles previously described for whole brain. Regional glucose values correlate closely with those reported for the 14C-deoxyglucose technique. The method has the advantages of 1) a much shorter experimental period, 2) a relatively simple mathematical treatment, and 3) the utilization of the actual, fully metabolizable substance itself, glucose, as the label. In addition to normal rats, regional values are reported for 20 individual brain areas of rats in bicuculline induced status epilepticus, rats intoxicated with ammonium and rats anesthetized with pentobarbital sodium or ketamine.
The impact of overnight intravenous lipid emulsion (ILE) infusion on upper gastrointestinal tract physiology was assessed in 10 healthy volunteers. No changes in lower esophageal sphincter pressure (before infusion: 28 +/- 4 mm Hg; after infusion 20.5 +/- 3; p:NS), plasma concentrations of gastrointestinal hormones (gastrin: preprandial before/after lipids: 14 +/- 2.1/13 +/- 1.4 pM; postprandial before/after lipids: 28 +/- 2.7/30 +/- 3.4 pM, CCK: preprandial before/after lipids: 69 +/- 10/64 +/- 10 pM; postprandial before/after lipids: 96 +/- 11/95 +/- 12 pM; neurotensin: levels less than 6 pM in all samples; somatostatin levels undetectable in all samples) nor on pathologic gastroesophageal reflux episodes (% of time of pH less than 4, before/after lipids: 0.6 +/- 0.4/0.15 +/- 0.09), were found (p = NS). In contrast, technetium gastric emptying studies showed a significant delay when comparing pre- and post-lipid infusion values (37 +/- 4/54 +/- 4%) (p greater than 0.005). The mechanism of this effect remains unexplained.
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