Serum pesticide concentrations in farming cooperatives in Honduras.
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Adult↗
Biomedical subjects
D L Phillips
Publications and source records attributed to D L Phillips.
Determination of trace elements in human hair. Reference intervals for 28 elements in nonoccupationally exposed adults in the US and effects of hair treatments.
The concentrations of 28 elements in hair of three populations of non-occupationally exposed adults in the US (n = 271) were determined. The 10th, 50th, and 90th percentiles, and geometric means for these data were obtained to define reference intervals for these elements. The effects of various hair treatments, age, and sex on concentrations of 17 selected elements in hair were determined for these populations. Age had little effect on elemental concentrations. Males tended to have higher Cd and Pb levels, but lower Mg and Ti levels than females. Males using dandruff shampoo had significantly higher concentrations of Na, Se, and Ti than those using only regular shampoo and/or conditioners. Ba, Ca, Cu, Mg, Na, and Sr were all elevated in females using permanents or color treatments, compared to those using only dandruff shampoo, regular shampoo, and/or conditioners.
Adult↗
Age dependence of metals in hair in a selected U.S. population.
Concentrations of 28 metals were determined in hair samples from 199 children (age less than or equal to 12 years) and 322 adults (age 13-73) years. Levels of calcium, barium, magnesium zinc, and strontium all show a similar age-dependent increase up to about 12-14 years; levels of aluminum show a decrease with age. Relationships of elemental concentrations with age were examined by using correlation, linear regression, t tests, and discriminant analysis. Statistically significant differences in mean concentration values between children and adults were shown for these metals. Discriminant analysis gave about 95% accuracy in classifying a test data set into the categories of children and adults. A hypothesis suggested by the data is that there is an age-dependent excretion in hair of alkali metals during skeletal growth and development. The observed decrease in aluminum is largely unexplained at this time.
Adolescent↗
Estimates of the half-life of 2,3,7,8-tetrachlorodibenzo-p-dioxin in Vietnam Veterans of Operation Ranch Hand.
The half-life of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD; commonly known as dioxin) in serum has been measured in 36 Air Force Vietnam veterans of Operation Ranch Hand, which was the operation that aerially sprayed the herbicide Agent Orange in Vietnam. From serum specimens taken in 1982 and 1987, the median half-life of 2,3,7,8-TCDD in these Ranch Hand veterans was found to be 7.1 yr (95% confidence interval about the median of 5.8-9.6 yr). These veterans reported no civilian exposure to dioxin or herbicides. Concentrations of 2,3,7,8-TCDD in the 1982 serum specimens from these veterans ranged from 16.9 to 423 parts per trillion on a lipid weight basis. The half-life estimates were not associated with the concentration of 2,3,7,8-TCDD in the 1982 serum specimens. This half-life of 7.1 yr is much longer than the half-life of 2,3,7,8-TCDD reported in animals but is consistent with recent evidence from other human exposures to 2,3,7,8-TCDD.
Adult↗
Detection of bluetongue virus in bovine fetuses using the avidin-biotin complex immunoperoxidase method.
The avidin-biotin complex immunoperoxidase technique was adapted for use in detecting bluetongue virus (BTV) antigens in BTV serotype 11-infected bovine fetuses. Fetuses were infected with BTV serotype 11 at 120 days of gestation and then removed 20 days later by Cesarean section. Blood and tissue samples were collected from each animal and used for virus isolation in embryonated chicken eggs, the immunofluorescent antibody test, and the avidin-biotin complex test. The avidin-biotin complex method successfully identified BTV antigens in both fresh and autolyzed fetal brains. Thus, the avidin-biotin complex immunoperoxidase method has potential as a possible procedure for diagnosing bluetongue disease in aborted bovine fetuses.
Abortion, Veterinary↗
Sex steroids and bone density in premenopausal and perimenopausal women.
Bone density begins to decline in women before menopause, and the degree of bone loss is variable. We performed a cross-sectional analysis on the entry data of a 5-yr prospective study of risk factors for osteoporosis to determine the correlation of bone density with serum sex steroid concentrations and body weight. We studied 292 healthy white women, aged 35-50 yr, who were menstruating regularly or had had menses in the past 12 months. Blood samples were drawn in the early follicular phase for estradiol (E2), testosterone (T), dehydroepiandrosterone sulfate, and sex hormone-binding globulin (SHBG). Free levels of E2 (FE2) and T (FT) were calculated based on total T and E2, SHBG, and albumin levels. Women were classified as premenopausal (FSH, less than 12 U/L) and perimenopausal (FSH greater than or equal to 12 U/L; n = 46; 16%). Bone density was measured by dual photon absorptiometry of the lumbar spine (L2-L4) and hip and by single photon absorptiometry of the wrist. Perimenopausal women were older than premenopausal women (45.5 +/- 3.5 and 41.0 +/- 3.9 yr, respectively), but did not differ in height or weight. While bone density did not correlate with age in each group, perimenopausal women had significantly lower bone density at the L2-L4 and femoral neck (L2-L4, 1.18 +/- 0.14 in perimenopausal and 1.24 +/- 0.12 g/cm2 in premenopausal women; femur, 0.84 +/- 0.11 in perimenopausal and 0.90 +/- 0.11 g/cm2 in premenopausal women; P less than 0.005). Body weight showed the strongest positive correlation with bone density. Log FT, percent FT, and FE2 percent correlated positively with bone density, even after controlling for weight. Log SHBG was negatively correlated with bone density in premenopausal women at the hip and wrist after controlling for weight. FSH was inversely correlated with bone density, and E2 and T were lower in perimenopausal than premenopausal women. These data suggest that women who are still menstruating may have relative deficiencies in both E2 and T, with reduced bone densities as a consequence.
Adult↗
Effects of folate in culture medium on common fragile sites in lymphocyte chromosomes from normal and leukemic children.
The expression of common fragile sites at 69 bands was evaluated in 20 normal children and in 15 children with newly diagnosed acute leukemia using medium with folate (FA+) and without folate (FA-). As expected, the FA- medium significantly increased expression of aberrations in all study groups but the differences were larger for normal children than leukemic children. The major effect of the FA- medium was a generalized increase in aberration frequency over all sites rather than site-specific increases. A tendency toward clumping of aberrations within cells was exhibited in both media. Aberrations were seen at 81% (FA+) and 83% (FA-) of the 69 bands, with 4 sites - 3p14, 6p21, 9q13, and 17q23 - recorded in most of the study individuals. In addition, 12 sites not previously recorded as common or rare sites had significant levels of expression in at least one study group.
Acute Disease↗
A comparison of Harrington rod fixation with and without segmental wires for unstable thoracolumbar injuries.
Between January 1, 1975 and November 1, 1986, 77 patients with acute unstable thoracic or lumbar spine fractures underwent reduction, posterior stabilization with dual Harrington distraction rods, and fusion with autogenous iliac crest bone graft at Vanderbilt University Medical Center. Beginning March 1985, in 25 patients, segmental interspinous wires were employed, in addition to the Harrington rods, to augment the surgical construct. Clinical and radiographic analysis was performed to determine if differences existed between the two groups. Average time to surgery, hospital stay, and time to brace discontinuance were lower in the segmental wire group. Pain and work status at final follow-up were similar in the two groups. There was a higher incidence of superior and inferior hook migration and reoperation for this complication in patients treated with Harrington rods alone. There was no significant difference in postoperative correction of deformity, although at follow-up, there was greater recurrence of deformity in the Harrington rod group. In summary, the use of segmental wires to supplement Harrington rod fixation appears to offer advantages over Harrington rods alone, with minimal or no increased risk.
Adolescent↗
Effect of lot-to-lot variability in filter paper on the quantification of thyroxin, thyrotropin, and phenylalanine in dried-blood specimens.
We prepared whole-blood pools to contain various concentrations of phenylalanine (Phe), thyroxin (T4), and thyrotropin (TSH) and applied them to six different lots of Schleicher & Schuell Grade 903 filter paper, two of which represented extremes for serum-absorbancy. Individual measured T4 values showed minimal overlap among all pools for each individual filter-paper lot and for all lots combined, but Phe values overlapped considerably among the high-concentration pools within and among lots. Individual TSH values also showed considerable overlap among the high-concentration pools for all lots combined, but little overlap within each lot. Maximum differences in mean observed values among lots ranged from 6% to 36% for all analytes. Assay results from hemolyzed blood specimens generally were lower than from intact-cell blood specimens for T4 and TSH, but slightly higher for Phe. Maximum among-lot differences in mean values ranged from 13% to 29% for all analytes when each tested lot was used for assay calibration. Lot-to-lot differences in measured values were not strongly related to serum absorbancy values. We conclude that routinely encountered within- and among-lot filter paper variability, as measured by serum-absorbancy, is not alone sufficient to cause gross quantification errors in neonatal screening programs.
Absorption↗
Quantitative differences among various proteins as blocking agents for ELISA microtiter plates.
We tested instantized dry milk, casein, gelatins from pig and fish skin, serum albumin and several other proteins for their abilities to block non-specific binding (NSB) of a peroxidase-conjugated immunoglobulin to polystyrene microtiter plate wells. Each blocking protein was tested across a million-fold concentration range, both in simultaneous incubation with the peroxidase conjugate and as a pretreatment agent where excess protein was washed away before incubation with the conjugate. Overall, instantized milk and casein were the most effective proteins tested: they inhibited NSB by over 90% in both the simultaneous and pretreatment modes at far lower concentrations than most of eight other proteins. Enzymatically hydrolyzed porcine skin gelatin was the least effective protein tested: it did not reduce NSB by more than 90% even at its highest concentrations; its blocking ability fell rapidly upon dilution; and it was almost useless as a pretreatment agent. Fish skin gelatin showed much better blocking activity than hydrolyzed porcine gelatin, and it still had the practical advantage of remaining fluid even under refrigeration. Our results suggest that some proteins (such as casein) block NSB to plastic primarily through protein-plastic interactions, while others (such as porcine skin gelatin) block primarily through protein-protein interactions. Although the optimal blocking agent for any particular ELISA system must be determined by empirical testing, these results should be helpful in selecting the best possible candidate proteins for further evaluation.
Animals↗
Isolated metastasis to small bowel from anaplastic thyroid carcinoma. With a review of extra-abdominal malignancies that spread to the bowel.
Symptomatic involvement of the small bowel by isolated metastasis from an extra-abdominal primary malignancy is rare, most commonly resulting from malignant melanoma and lung cancer. A few other extra-abdominal tumors, not including thyroid cancer, have been documented on rare occasions to present with small-bowel involvement as the first evidence of metastasis. We report a case of anaplastic thyroid carcinoma with isolated symptomatic metastasis to the small intestine. We review the literature regarding the frequency and origin of extra-abdominal malignancies developing small-bowel metastases and the spectrum of clinical manifestations resulting from this syndrome.
Aged↗
Estimation of the time component in the movement of chemicals in contaminated groundwater.
For a proper analysis of the potentially causal relationship between exposure to volatile organic chemicals (VOCs) in drinking water and health events, it is essential to know T1, the time when exposure started, and C = f(T), which is the change of the VOC concentration C as a function of time T and the total accumulated exposure (TAE) to VOCs to which an individual was exposed. In the typical situation of incidentally detected pollution of groundwater, no such information is available. This paper describes the development of a method for estimating T1, C = f(T), and TAE as part of an epidemiologic study of the health effects of VOC contamination of an aquifer serving public and private wells. Pooled test results of city wells, tested periodically since 1981, provided the data base for developing a statistical model for estimating C = f(T). This model was then applied to private wells, for which the data of only one water sample were available, to retrospectively estimate their T1. The best-fitting model was a multiple linear regression equation consisting of the natural logarithm of the VOC concentration as the response variable, with the time of sampling, the distance of the wells from the source (expressed as coordinates), the well depth, and the well capacity as determinants. The TAE was calculated by integrating the area under the time-concentration curve.
Models, Theoretical↗
Alanine aminopeptidase in serum: automated optimized assay, and effects of age, sex, smoking, and alcohol consumption in a selected population.
In the diagnosis of chronic (as opposed to acute) liver diseases, combinations of indicators are needed to improve specificity. Alanine aminopeptidase (AAP; microsomal aminopeptidase, EC 3.4.11.2) activity in serum reportedly is a very sensitive indicator of intrahepatic cholestasis and biliary obstruction; it is also particularly useful in diagnosing chronic liver disease when combined with an indicator of hepatocyte damage such as aspartate aminotransferase or alanine aminotransferase. We optimized the assay of AAP in serum, automated the assay by using a centrifugal analyzer, then used this automated assay to determine activity in 202 individuals, ages one to 73 years. The preliminary results were analyzed in terms of the effects of age, sex, smoking, and alcohol consumption on AAP activity in serum. Striking sex-related differences were observed: AAP activity in males declined 2.5 times more rapidly with age than did that in females; indeed, activity in adult females remained essentially constant. Moreover, AAP values were higher in men who smoked than in those who did not, the difference being of borderline significance by analysis of covariance (p = 0.0865) but significant by partial correlations (p = 0.02). No similar differences were seen for women smokers and non-smokers. When the effects of other variables were held constant, alcohol consumption alone did not significantly correlate with AAP activity in men or women.
Adolescent↗
Hematologic manifestations of gastrointestinal disease.
A diverse number of hematologic abnormalities may occur in association with gastrointestinal disease. For example, deficiencies of iron, folate, and vitamin B12 often accompany and may be the first clue to diseases such as colon cancer, celiac sprue, and chronic gastritis, respectively. A compilation of the hematologic disorders associated with diseases of the gastrointestinal tract, liver, and pancreas is provided.
Esophageal Diseases↗
Seventh interim progress report of the british institute of radiology fractionation study of 3F/week versus 5F/week in radiotherapy of the laryngo-pharynx.
A fresh analysis of the data entered into the multicentre BIR fractionation trial of 3F/week versus 5F/week in radiotherapy of the laryngopharynx has been undertaken. Completed records of the 732 patients initially entered into the trial have now risen from 687 at the last report to 706. The data have been analysed in a manner similar to that adopted previously so as to measure the effects of the two regimes on both tumour and normal tissues, and some additional analyses have now also been made. There have been some modifications in the results in the various sub-groups which may be due to an inadequate number of patients having been followed up for long enough at the time of the previous analyses. More data for late radiation damage to normal tissues and new radiobiological findings have suggested possible explanations for the differences which have emerged between the two groups. The apparent differences between the sub-groups containing patients with highly localized tumours, which were reported in our previous report, are now less marked and not statistically significant.
Carcinoma, Squamous Cell↗
Radiotherapy in the treatment of localised non-Hodgkin's lymphoma (Report no 16).
This report describes the experience of the BNLI in the treatment of localised (Stage I, II) non-Hodgkin's lymphomas (NHL). About a third of all patients with NHL presenting to collaborators in the BNLI were considered after investigation to have localised disease. This relatively large number suggests that some cases may have been understaged. Patients with Grade 1 disease were treated with either local irradiation or with local irradiation followed by chlorambucil. Survival rates in the two groups were essentially similar and it appeared that radiotherapy alone provided equally effective treatment. Patients with Grade 2 lymphomas were treated with either local irradiation or with local irradiation followed by COP. Primary nodal disease was not obviously affected by the addition of chemotherapy. Extranodal disease arising in the gut below the diaphragm appeared to be adversely affected by the irradiation which was of necessity spread over several weeks, delaying the use of chemotherapy. Extranodal disease arising in the head and neck region is controlled in about 80% of patients and the routine use of prophylactic combination chemotherapy confers no benefit to the patient.
Chlorambucil↗
Sensitivity of the carotid body to within-breath changes in arterial PCO2.
Respiration, sinus nerve chemoreceptor discharge, and carotid arterial pH were monitored in cats. Chemoreceptor discharge frequency showed oscillations that had a respiratory period when averaged over many respiratory cycles. These oscillations disappeared when pH oscillations of respiratory period were eliminated from the carotid arterial blood. The maximum sinus nerve discharge was associated with the most acid point of the recorded pH oscillation. Briefly increasing PCO2 by giving CO2-rich saline into the aortic root resulted in brief reduction in carotid arterial pH, and when this reduction occurred during inspiration tidal volume increased, even with a pH change no larger than the pH oscillations. However, increased chemoreceptor discharge could only be demonstrated when each pH change had twice the amplitude of the pH oscillations. Injections of fixed acid mixed with free carbonic anhydrase transiently increased chemoreceptor frequency, whereas injections of fixed acid alone had no effect. The carotid body is therefore sensitive to small rapid changes in arterial PCO2, and the pH electrode record indicates the size of the stimulus except when fixed acid changes are produced too closely upstream.
Animals↗