Biomedical subjects
Publications and source records attributed to D W Young.
David Young argues that although doctors are interested and willing to use computers, in general they do not use them in health care. It is a complex matter, but an important reason is that the system designers have ignored the clinical environment and the motivation of doctors. In particular the conventional approach to data input is inappropriate, and he suggests a better way.
Pathologic conditions involving the temporal bone in infants and children are now commonly diagnosed by computed tomography (CT). The importance of utilizing high resolution computed tomography (HRCT) with magnified, thin (1.5 mm) scans in both the axial and coronal planes is stressed in order to obtain the maximal anatomic information that is critical for proper diagnosis. A retrospective analysis of 388 cases reveals a positive diagnostic yield ranging from 65% in temporal bone trauma to 20% in clinically suspected neoplasm. Selected case reports of congenital abnormalities, inflammatory processes, traumatic lesions, and tumors will be presented. We conclude that HRCT is an excellent diagnostic modality and should be used liberally to evaluate the temporal bone in children.
The predominant form of gastrin in the antral mucosa of the stomach of virtually all species previously examined is the 17 amino acid peptide little gastrin (G17). This report describes the occurrence in equine antral mucosa of an immunoreactive form of gastrin with elution properties on Sephadex G-50 superfine similar to human unsulfated big gastrin (G34-I). This putative equine big gastrin was a major component of the gastrin immunoreactivity present. A second peak of activity in equine antral mucosa eluted in an identical manner to human little gastrin (hG17-I). Inhibition curves of equine big and little gastrin, with the gastrin radioimmunoassay utilized in this study, were parallel. This observation indicates that there was no spurious increase in the apparent relative amount of big gastrin due to significant differences in the RIA antibody cross-reactivity to big and little equine gastrin. The equine big gastrin peak was resolved by ion exchange chromatography into unsulfated and sulfated forms in approximately equal amounts. This data implies that posttranslational processing of gastrin in horses may differ from that of species previously studied.
Single photon emission computerized tomography (SPECT) is finding greater clinical applicability in pediatric imaging. We applied the principles of SPECT imaging to renal cortical scintigraphy in the assessment of renal defects. We evaluated retrospectively 35 children who were undergoing 99mtechnetium-glucoheptonate renal cortical scintigraphy. Each child underwent planar, SPECT and pinhole imaging. Of the 35 children 9 had normal systems bilaterally and the remaining 26 had at least 1 defect in 1 or both kidneys. Over-all, we identified 29 abnormal renal units. Planar imaging identified 59% of the defects, while pinhole and SPECT imaging identified 83% of the defects. When combining any 2 studies (that is planar and pinhole, planar and SPECT or pinhole and SPECT) we were able to identify 97% of the defects, which approached but was not statistically significant at p = 0.09. When data from all 3 studies were combined 100% of the defects were identified, which was a statistically significant increase in defects noted when compared to only planar images (p = 0.016). SPECT imaging was found to be a technically feasible undertaking with conventional equipment, although its clinical applicability at this time is limited.
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The antineutrophil cytoplasmic antibody test has become available over the past 4 or 5 years. It is positive in a limited number of conditions whose characteristic feature is the presence of a small vessel vasculitis. These include Wegener's granulomatosis and microscopic polyarteritis. The test was applied to 63 patients with uveitis of various types. 14 positive tests were found amongst which anterior uveitis was the most common disease present.
A 5-year-old spayed Shetland Sheepdog had clinical signs consistent with hypothyroidism. Laboratory findings, including subnormal serum T4 concentration, also were suggestive of hypothyroidism; however, the apparent serum T3 concentration, as determined by a solid phase assay, was extremely high. Thyroid scintigraphy revealed ectopic radionuclide uptake in the neck and thyroid biopsy revealed lymphocytic thyroiditis. Determination of T3 autoantibody titer confirmed that the previously measured high serum T3 concentration was spuriously high because of autoantibodies to T3.
The effects of single i.v. and p.o. doses (5 mg/kg) of fenbendazole, were evaluated on thyroxine, tri-iodothyronine, corticosterone, hematology, clinical chemistries, and serum proteins in 10 white Pekin ducks. Fenbendazole was administered i.v. (n = 5) as a 3% dimethyl sulfoxide solution and p.o. (n = 5) as a 10% commercial suspension. Serum enzyme concentrations, total protein and protein fractions, glucose, cholesterol, uric acid, sodium, and potassium were unchanged from baseline values. Serum triglycerides decreased consistently in the i.v.-treated group but remained unchanged in the p.o.-treated group. Serum chloride was consistently elevated above baseline values for both i.v.- and p.o.-treated ducks, while inorganic phosphate was consistently decreased only in the i.v.-treated group. Hemoglobin and hematocrit values generally were below baseline values. Leukocyte values varied considerably and were not significantly different from baseline values. Serum thyroxine and tri-iodothyronine values in both the i.v.- and p.o.-treated groups were not changed significantly from baseline values. Serum corticosterone values were not changed in the i.v.-treated groups but they were decreased at various times in the p.o.-treated group. Although there were some sporadic significant changes in the parameters measured versus baseline values all values remained within the physiologic limits for ducks. The safety of fenbendazole has been previously demonstrated for several species.
Postprandial gastrin concentrations were assayed in serum samples from a group of six foals at one day, one week, one month and three months of age. Before sampling, each foal was prevented from feeding for 2 h and was then allowed to suck for 15 mins. Blood samples were taken at the start of the meal and at 30 min intervals for the next 3 h. Feeding increased serum gastrin concentrations at one day, one week and one month, with the greatest increases detected at one day. Mean pre-feeding gastrin concentrations were 25.2 +/- 2.3 pg/ml at one day, 22.8 +/- 3.9 pg/ml at one week, 15.2 +/- 2.3 pg/ml at one month and 15.6 +/- 7.5 pg/ml at three months. Highest mean post prandial concentrations were at 60 mins on Day one (47.4 +/- 15.2 pg/ml) and one month (25.2 +/- 4.1 pg/ml) old foals. There was no apparent post prandial increase in serum gastrin concentrations in foals at three months of age. Precise reasons for changes in postprandial serum gastrin concentrations remain unknown. Factors that could be important include maturation of G cell function, alterations in gastrin metabolism and excretion, and changes in gastrointestinal motility with increasing age.
Gastrin is the only hormone known to stimulate secretion of hydrochloric acid. It also has trophic effects on specific parts of the mucosa of the gastrointestinal tract. Using radioimmunoassay techniques, postprandial serum gastrin and insulin concentrations were measured in six adult horses to establish effects of different diets on gastrin concentrations. Insulin concentrations were measured to provide support to the patterns of gastrin secretion because patterns of insulin secretion were already known. The horses were fed coastal bermuda hay, or twice daily 5 kg of a complete pelleted ration, 5 kg of commercial sweet feed or 5 kg of the sweet feed together with hay. There was little change in serum gastrin or insulin concentrations after feeding hay alone. Rations containing more readily available nutrients (pellets, sweet feed) produced significant increases in postprandial serum gastrin and insulin concentrations. Gastrin concentrations also varied according to the duration of feeding each diet, but this was not seen with insulin. These results indicated that gastrin secretion, and therefore possibly gastric acid secretion, were markedly influenced by dietary composition and duration of feeding a diet. There appeared to be some adaptation of the stomach (gastrin secretion) to changes in diet, but this was not accompanied by indications of adaptation in the endocrine pancreas (insulin secretion).
A clear association between the use of cinnamaldehyde containing toothpaste and inflammation of the lips, labial mucosa, and gingivae is described in a 59-year-old man. The sensitivity reaction was verified by patch testing with cinnamaldehyde.
Workplace programs make the supervisor responsible for identifying alcoholics through their job performance. However, research indicates that those so identified are a small proportion of the alcoholic employed population and tend to be in the later stages of the disease. This is due in part to the relatively small number of alcoholics who demonstrate performance deterioration in the early stages. In addition, only a few members of the drinking population are responsible for the costs to the organization resulting from poor job performance. The identification rate differs for alcoholics depending on their sex and level in the organization and the supervisory style of their managers. Hiding symptoms and cover-up for others adds to the proportion remaining unidentified. While identification through performance evaluation may be considered the only legitimate procedure in the workplace, it is not in fact identifying anywhere near the estimated number of alcoholics. The administrators and researchers in the employee assistance/occupational alcoholism field will have to decide whether to try innovative procedures that will broaden the scope of traditional programs. Such procedures may include cooperating with health promotion programs and identification through genetic and familial screening. While the current model identifies those most destructive to the organization, it bypasses a significant group of employees who are currently a danger to themselves or potentially a problem for the organization.
Influencing the ordering of laboratory investigations, and in particular reducing unnecessary ones, is a vital concern to many hospitals. An account of the reasons why control is necessary is presented. The different methods evaluated are reviewed, including rationing, form design, resource management (budget control), education, protocols and decision support systems, incentives, feedback and case note appraisal. Methods of controlling the requesting of investigations are likely to be ineffective unless they take place in the correct environment. Elements of this include correct attitude and commitment by senior staff, a long term strategy, and different approaches for different groups of doctors.
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A study of 3,5,3'-L-triiodothyronine autoantibody (T3 AA) in 18 dogs revealed an average apparent affinity constant for T3 of 2.24 +/- 1.78 X 10(10) M-1, an average T3 binding capacity of 639.3 +/- 666.5 ng/dl and a low thyroxine (T4) cross-reactivity (less than 1%) in all samples tested. A valid radioimmunoassay (RIA) procedure which involved heat treatment of samples for 1 hr at 70 degrees C and assay on Sephadex minicolumns was developed for measuring T3 in the presence of T3 AA. Total T3 was elevated (mean = 374.8 +/- 158.4 ng/dl) in samples in which T4 was in the normal canine range, but T3 was lower (mean = 96.1 +/- 63.3 ng/dl) in samples with T4 values in the hypothyroid range. For each sample the concentration of T3 not bound by T3 AA was calculated from the total T3 concentration, the affinity constant, and the binding capacity. In dogs with normal total T4 concentrations the average calculated T3 not bound by T3 AA was 147.2 +/- 144.4 ng/dl while in dogs with low total T4 the value was 15.7 +/- 26.3 ng/dl (normal canine range is 45-150 ng/dl). Canine samples containing T3 AA were compared to serum from three rabbits actively immunized against T3 to provide anti-T3 for commercial RIA. The rabbit T3-antisera had an average T3 affinity constant similar to those of the canine samples (1.57 X 10(10) M-1), but had average titer, T3 binding capacity, and total T3 values more than 10-fold higher. Our findings indicate that, in dogs with serum containing T3 AA and normal total T4 concentrations, a compensatory mechanism appears to exist to maintain non-T3 AA bound T3 within the range of normal total T3. This compensatory mechanism does not operate in those dogs with insufficient thyroid activity to maintain normal total T4 values.
A commercial radioimmunoassay kit designed for measuring gastrin in human serum was validated for use with equine serum. This nonextraction, double-antibody procedure uses an antiserum with broad specificity for molecular forms of gastrin. Synthetic human gastrin (G17-I) was added to pooled equine serum, and the observed assay values were compared with the mass added. Recovery was 99 to 115% in the gastrin concentration range of 40 to 640 pg/ml. Dilutions of postprandial serum with serum from fasted horses were assayed, and the inhibition curves were compared with those of the human gastrin kit standards, using a log-logit transformation. The slopes of the sample dilution plots were not significantly different from the slopes of the standard curves. Ethylenediamine tetraacetate and heparin adversely affected the assay, resulting in lower assayed gastrin concentration values. The intra-assay coefficient of variation (n = 10) was 3.8%, and the interassay coefficient of variation (n = 6) was 11.2%. The assay sensitivity, as reported by the manufacturer, is 8 pg/ml. Gastrin concentrations in serum from fasted horses ranged from undetectable values (less than 8 pg/ml) to 17.5 pg/ml, and peaked at a mean value (n = 6) of 70 pg/ml 3 hours after feeding. Serum cortisol values monitored during the postprandial blood collection period were in the normal range for horses.
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Potential factors underlying sex differences in the referral of problem-drinking subordinates to employee assistance programs (EAPs) were explored in interviews with 120 supervisors in four organizations. Analyses of data obtained in these interviews assessed the relative ability of eight variables to predict supervisor's actual identification and referral of female and male problem drinkers. In addition to numbers of employees supervised, the supervisors' judgment of the EAP's effectiveness was the best predictor of referral and identification, regardless of the sex of the referred subordinate. Knowledge and training in the EAP was a secondary contributor to referral of men, but played no role in female referrals. When controlling for all other variables, the extent to which supervisors held an egalitarian attitude toward women's rights and roles was found to be marginally positively related to identification of female drinkers. Similarly, a less stigmatized, stereotyped view of women's use and abuse of alcohol was marginally associated with a greater likelihood of referral of a female drinker to the EAP. Neither of these attitudinal variables was related to identification or referral of male problem drinkers.