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PubMed1986

HLA antigens, blood groups and immunoglobulin levels in idiopathic thrombocytopenic purpura.

Thirty-three patients with idiopathic thrombocytopenic purpura (ITP) were tested for HLA-A, B and C antigens, platelet antibodies, immunoglobulin levels and ABO blood groups. With one exception, ITP proved not to be significantly associated with the HLA antigens studied; an increased frequency of HLA-A28 was found in chronic ITP patients (50 vs. 18.7% in the control population). An increased incidence of blood group A was found in ITP patients (64 vs. 37.98% in the control population), especially in those with acute ITP (84.7%). A significant reduction of IgG levels was noted in patients with chronic ITP, while below-normal levels of IgA were found in both chronic and acute ITP patients. There was no difference in levels of IgM. Circulating platelet isoantibodies were demonstrated in 67.6% of the ITP patients. No correlation was demonstrated between the presence of platelet antibodies, immunoglobulin levels of HLA antigens.

Acute Disease↗
PubMed1997

Acanthamoeba keratitis: is water exposure a true risk factor?

PURPOSE: Water exposure has been commonly cited in the literature as a significant risk factor for the development of Acanthamoeba keratitis. The purpose of this study was to test the hypothesis that the incidence of tap and contaminated water exposure in Acanthamoeba keratitis patients is no higher than in the normal contact lens population. METHODS: We retrospectively reviewed all patients all patients diagnosed with Acanthamoeba keratitis at Massachusetts Eye & Ear Infirmary from 1990-1994, and compared this group to a control population of healthy contact lens wearers assessed by a self-report questionnaire. RESULTS: A history of water exposure was reported by 64% (seven patients) diagnosed with Acanthamoeba keratitis. In comparison, 100% of the control population of healthy contact lens wearers (100 patients) reported comparable water exposure, and 87% of controls reported multiple sources of water exposure. CONCLUSIONS: The finding that the incidence of water exposure is actually lower in patients with Acanthamoeba keratitis than in the general contact lens population suggests that water exposure may be less important, and other factors more important in the development of this disease than previously assumed.

Acanthamoeba↗
PubMed1975

Changes in relative aggressiveness and social dominance associated with selection for early egg production in chickens.

We tested the hypothesis that artificial selection for early reproductive performance of chickens kept under competitive conditions increases aggressiveness and social dominance. Two populations subjected to long-term selection for number of eggs laid before 40 weeks of age and the unselected control population from which they derived were used. Results generally supported the hypothesis but indicated that increased aggressiveness associated with such selection may characterize the adolescent period only. For one of the selected strains, rank for aggressiveness and social dominance between adolescence and full maturity was reversed, relative to the control population. Associations between increased aggressiveness (and social dominance) and decreased age at sexual maturity are discussed, along with implications as to the role of social status and reproductive performance when different genetic strains compete within flocks.

Aggression↗
PubMed1999

Sample size calculations when outcomes will be compared with an historical control.

The usual formulae for calculating sample size are not valid when a treated cohort will be compared with an historical control population. Methods appropriate for a single group study may greatly underestimate the required sample size because they, in effect, assume a control population of infinite size. Methods appropriate for a two-group study require specification of the proportions of patients in the two groups--a requirement that can not be met when the size of the historical control group is fixed. An easily programmed iterative solution is presented and simulations indicating the validity of the method are performed.

Algorithms↗
PubMed2003

Subclinical disease activity in systemic lupus erythematosus: immunoinflammatory markers do not normalize in clinical remission.

OBJECTIVE: To correlate various laboratory measures in systemic lupus erythematosus (SLE) with the British Isles Lupus Assessment Group (BILAG) disease activity index, to search for organ-specific laboratory patterns and to compare with a control population. METHODS: A cohort of 57 Caucasian outpatients fulfilling the American College of Rheumatology criteria for SLE and a control population of 17 patients admitted for coronarography were examined. Disease activity was assessed with BILAG index. Plasma samples were investigated for sCD44, interleukin 6 (IL-6), IL-10, IL-12, tumor necrosis factor-a (TNF-a), soluble TNF receptor-55 (sTNFR-55), sTNFR-75, IL-1-receptor antagonist, soluble intercellular adhesion molecule (sICAM), soluble vascular cell adhesion molecule (sVCAM), E-selectin, and neopterin as well as for C3, C4, dsDNA, and other conventional indicators. RESULTS: Thirty-nine patients had inactive disease (total BILAG score < or = 5), 18 patients had active SLE. Surprisingly, except for C-reactive protein (p < 0.001), no statistically significant difference of the laboratory indicators was found between patients with active and those with inactive SLE. However, there was a significant difference between SLE patients and controls for sTNFR-75 (p < 0.008). We found significant correlations between laboratory markers and some BILAG organ system scores, such as between IL-1ra and the musculoskeletal score (p < 0.003) and between sTNFR-55/sTNFR-75 and renal BILAG (p < 0.001, p < 0.004, respectively). Significant nonparametric correlations were revealed between C3 and C4 (p < 0.0001), and between sTNFR-75 and dsDNA, neopterin, sVCAM, sICAM and sTNFR-55 concentrations (p < 0.0001 for all), and between sTNFR-75 and IL-1ra (p < 0.006). CONCLUSION: Patients with SLE in clinical remission show ongoing systemic immunoinflammatory activity measured with a variety of cytokines, adhesion molecules, and other inflammatory markers. This indicates that laboratory measures may provide qualitatively different additional information to validated disease activity indexes such as the BILAG. Different laboratory markers correlate with disease activity in different organ systems. This suggests differences in pathogenic mechanisms in SLE depending on the organ system involved.

Adult↗
PubMed1986

Renal disease from habitual antipyretic analgesic consumption: an assessment of the epidemiologic evidence.

The quantitative evidence relating habitual antipyretic analgesic consumption to the development of renal disease is reviewed. For purposes of analysis, "abuse" of analgesics is defined as regular, usually daily consumption. The prevalence of habitual consumption demonstrates marked geographic variation for poorly defined reasons. Prevalence tended to be highest in those populations in which phenacetin was available and popular. The prevalence of nephropathy among habitual consumers also shows marked interpopulation variability. A highly significant linear relationship exists between the prevalence of habitual analgesic consumption in a given population and the prevalence of nephropathy in the subset of that population that habitually consumes analgesics. This relationship may represent a dose-response curve relating amount of analgesic intake to prevalence of nephropathy. Four cross-sectional studies, 1 longitudinal, and 1 case-control study have shown significant differences in prevalence of nephropathy between habitual users of phenacetin-containing analgesics and control populations. Conversely, 2 cross-sectional studies and 1 case control study showed no difference between habitual users of analgesics and control populations. However, those studies showing no difference were performed in populations with low prevalence of habitual consumption of compound analgesics and a lower prevalence of nephropathy than was found in those populations where differences were observed. The relative risk for developing various manifestations of analgesic nephropathy has been estimated in 4 studies and varies depending on which abnormality is considered. Data are available only for subjects consuming phenacetin-containing compound analgesics. The relative risk for elevated serum creatinine is in the range of 8 to 11, about twice that for an abnormal renal concentrating test (approximately 4). The relative risk for clinical papillary necrosis is approximately 18, and for cause-specific death (and by inference for end-stage renal disease) about 4. The difference in risk between most clinical manifestations of analgesic nephropathy and death (or end-stage renal disease) may be due to the fact that most patients with nephropathy do not progress to terminal renal failure. Rheumatology clinic studies indicate that the prevalence of nephropathy in habitual consumers of phenacetin-containing compounds is higher than that for habitual consumers of aspirin alone. Removal of phenacetin from compound analgesics in Scandinavian countries appears to have reduced the prevalence of papillary necrosis and death from interstitial nephritis.(ABSTRACT TRUNCATED AT 400 WORDS)

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

Interaction of noise-induced permanent threshold shift and age-related threshold shift.

Current medical-legal practices as well as an international standard (ISO 1999) assume the permanent threshold shifts produced by exposure to noise add (in dB) to the threshold shifts caused by increased chronological age (presbyacusis). This assumption, known as the additivity rule, was tested in an animal model. Mongolian gerbils, born and raised in a quiet vivarium, were exposed at age 18 months to a 3.5-kHz pure tone for 1 h at 113 dB SPL. At 6-weeks post-exposure, permanent threshold shifts in the exposed ear were approximately 20 dB in the 4- to 8-kHz region. Thresholds in the nonexposed, control ear were unaffected by the exposure. Animals were then allowed to age in the quiet vivarium until age 36 months and then were retested. Thus in a given animal, aging-only effects were assessed in one ear (internal control) and noise-plus-aging effects were assessed in the other (test) ear. A second control was mean age-related threshold shift measured in 48 gerbils who were born and raised in the quiet vivarium. This group is referred to as a non-noise-exposed population (population control). Using the additivity rule, predictions with either the internal or population control significantly overestimated noise-plus-aging effects. Use of the ISO 1999 compression factor reduced the overestimations by 0-5 dB. The intensity rule produced the most accurate predictions. These results suggest that the interaction of noise-induced permanent threshold shift and age-related threshold shift is not straightforward and that current medical-legal methods using the additivity rule overestimate the contribution of "noise effects".

Age Factors↗
PubMed1998

Modern oral contraceptive use and benign liver tumors: the German Benign Liver Tumor Case-Control Study.

OBJECTIVE: To analyze the association between oral contraceptive use and the risk of benign liver tumors. METHODS: Two parallel case-control studies on hepatocellular adenoma and focal nodular hyperplasia. Collaborative study of 15 German liver centers. Cases defined by histology and compared with population controls. RESULTS: Fifty-one hepatocellular adenoma and 143 focal nodular hyperplasia cases (women) were recruited between 1990 and 1997, and compared to 240 population controls with a recent abdominal imaging test. The frequency age-matched odds ratio was 1.25 (95% confidence interval (CI), 0.37-4.22) and 1.96 (95% CI, 0.85-4.57) for hepatocellular adenoma and focal nodular hyperplasia, respectively. For hepatocellular adenoma, there was neither a significantly increased risk with longer duration of oral contraceptive use, nor an association with time since first or last use. For focal nodular hyperplasia, however, a slightly increased odds ratio was found with longer duration of use and more recent last use. CONCLUSION: There is little evidence for an increased risk for hepatocellular adenoma in women using modern oral contraceptives. If there is a risk not detected by the limited study size, hepatocellular adenoma is an extremely rare, and focal nodular hyperplasia a rare, adverse effect potentially associated with long-term oral contraceptive use and likely to be without public health importance.

Adenoma, Liver Cell↗
PubMed2004

Age-structured optimal control in population economics.

This paper brings both intertemporal and age-dependent features to a theory of population policy at the macro-level. A Lotka-type renewal model of population dynamics is combined with a Solow/Ramsey economy. We consider a social planner who maximizes an aggregate intertemporal utility function which depends on per capita consumption. As control policies we consider migration and saving rate (both age-dependent). By using a new maximum principle for age-structured control systems we derive meaningful results for the optimal migration and saving rate in an aging population. The model used in the numerical calculations is calibrated for Austria.

Adult↗
PubMed2004

Chromosome and DNA damage analysis in individuals occupationally exposed to pesticides with relation to genetic polymorphism for CYP 1A1 gene in Ecuador.

DNA damage was measured by using the alkaline comet assay and the chromosomal aberration (CA) test using peripheral blood samples from 45 pesticide sprayers from Cayambe, Ecuador. From a total of approximately 200 nuclei scored for each donor with the comet assay, a highly significant increase in DNA migration was observed when compared with a similar unexposed control population. Additionally, in the CA test, the exposed individuals were found to be significantly different when compared to the control population. Polymorphisms for the CYP 1A1 (Msp I and Ile/Val) in exposed individuals were analyzed by PCR-RFLP and allele-specific PCR techniques. No association was found between the polymorphisms and higher levels of DNA damage as assessed by the comet assay.

Chromosome Aberrations↗
PubMed1988

Long-term outcome of patients undergoing surgical repair of isolated pulmonary valve stenosis. Follow-up at 20-30 years.

In a group of 191 consecutive patients who underwent operation at the Mayo Clinic for isolated pulmonary valve stenosis between 1956 and 1967, late results were excellent. In patients surviving operation before the age of 21 years, long-term survival was similar to that in an age- and sex-matched control population. In the other patients, late survival and functional status were good, but survival was poorer than in the control population. This late attrition, most likely due to the sequelae of long-standing right ventricular hypertrophy, suggests the need for continued surveillance. Late sudden death occurred in only three patients, between 10 and 21 years postoperatively. The finding of normal life expectancy for such patients who survive operation before age 21 is important for actuarial purposes and for the patients' career and employment plans.

Adolescent↗
PubMed1992

Fetomaternal hemorrhage in threatened abortion.

In this study, we compared the incidence of fetomaternal hemorrhage between patients with threatened abortion and a control population of similar gestational age. The study population comprised pregnant patients at less than 20 weeks' gestation who presented to our emergency room with a history of vaginal bleeding without cervical dilatation or passage of tissue. The control population consisted of women presenting for elective pregnancy termination; they were excluded from the study if they gave a history of any antepartum bleeding. The amount of fetomaternal hemorrhage was evaluated using the Kleihauer-Betke acid elution assay. A positive result in our laboratory, as determined by a nonpregnant control group, was a value of 0.07% or more fetal cells. Using this criterion, 11% of the study population had a positive Kleihauer-Betke test, compared with 4% in the pregnant control group. Rho(D) immunoglobulin may be indicated in Rho(D)-negative patients who present with threatened abortion.

Abortion, Threatened↗
PubMed1998

Breast cancer risk among women under 55 years of age by joint effects of usage of oral contraceptives and hormone replacement therapy.

OBJECTIVE: To assess effects on breast cancer risk of exposure to both oral contraceptives and menopausal hormones, an increasingly common exposure. DESIGN: A case-control study of breast cancer among women under the age of 55 years in Atlanta, GA involving 1,031 cases and 919 population controls was conducted. RESULTS: Ever use of oral contraceptives was associated with a relative risk of 1.1 (95% 0.9-1.4), whereas the relative risk for hormone replacement therapy was 0.9 (95% CI 0.7-1.2). Seventeen percent of the cases versus 19% of the population controls reported exposure to both agents, resulting in a relative risk of 1.0 (95% CI 0.7-1.4) relative to those unexposed to either preparation. Although there was little variation in risk associated with joint effects by either age or race, there were statistically nonsignificant elevations in risk for this exposure among women who had experienced a natural menopause (relative risk = 2.0, 95% CI 0.7-5.6), were relatively thin (relative risk = 1.5, 0.8-3.0), or who had a first degree relative with breast cancer (relative risk = 2.0, 0.6-7.0). When joint effects of longer term use of both agents were considered, subjects who reported use of oral contraceptives for 10 or more years and hormone replacement for 3 or more years had a relative risk of 3.2 (95% CI 1.4-7.4) compared with nonusers of either preparation. CONCLUSIONS: Although our results must be cautiously interpreted given small numbers within subgroups, they raise concern and emphasize the need for further evaluation on breast cancer risk of the increasingly common exposure to both oral contraceptives and hormone replacement therapy.

Adult↗
PubMed1982

[Platelet volume: comparative study of 2 populations of Greek and French origin].

The number and the volume of blood platelets in 306 normal adult persons of Greek origin were studied in Greece and compared with the corresponding values of 50 normal French adults. These controls were blood donors in the blood bank of the hospital "Necker-Enfants Malades" in Paris. In both phases of the study the same methods and techniques were used by one of the authors. The number of platelets of the Greek subjects (X1) was higher compared to those of the control population (X2) and this difference is statistically significant (means 1 = 295,970/microliters +/- 87,120, means 2 = 267,800/microliters +/- 63,700, P less than 0.05). The platelet volume was only slightly elevated in the Greek population compared to the French population, but this difference is not statistically significant (means 1 = 6.99 mu 3 +/- 2.49, means 2 = 6.59 mu 3 +/- 1.78, P less than 0.1). Our findings in the Greek population are different from those observed by Von Behrens (1975) on Mediterranean immigrants in Australia. Our values in the control population are similar to those of Paulus (1974), but differ from Von Behrens' data in North European subjects. Another observation of this study, is that sex and age (excluding youths) seems to have no influence on platelet volume, but platelet count in men is slightly affected by age.

Adult↗
PubMed1998

Quantitative DNA pooling to increase the efficiency of linkage analysis in autosomal dominant disease.

DNA pooling is an efficient method to rapidly perform genome-wide linkage scans in autosomal recessive diseases in inbred populations where affected individuals are likely to be homozygous for alleles near the disease gene locus. We wanted to examine whether this approach would detect linkage in autosomal dominant (AD) disorders where affected individuals may share one allele identical by descent at loci tightly linked to the disease. Two large outbred pedigrees in which the AD diseases familial venous malformation (FVM) and hereditary hemorrhagic telangiectasia (HHT1), linked to 9p and 9q, respectively, were investigated. Separate pools of DNA from affected (n = 21 for FVM and 17 for HHT1) and unaffected family members (n = 9 FVM and HHT1), and 25 unrelated population controls were established. Polymorphic markers spanning chromosome 9 at approximately 13.5-cM intervals were amplified using standard PCR. Allele quantitation was performed with a fluorimager. Visual inspection of allele intensities and frequency distributions suggested a shift in frequency of the most common allele in the affecteds lane when compared to control lanes for markers within 30 cM of the FVM and HHT1 loci. These subjective assessments were confirmed statistically by testing for the difference between two proportions (one-sided; P < or = 0.05). When using population controls, the true-positive rates for FVM and HHT1 were 5/5 and 2/5 markers, respectively. False-positive rates for FVM and HHT1 were 3/9 and 2/9, respectively. In both AD diseases investigated, quantitative DNA pooling detected shifts in allele frequency, thus identifying areas of known linkage in most cases. The utility of this technique depends on the size of the pedigree, frequency of the disease-associated allele in the population, and the choice of appropriate controls. Although the false-positive rate appears to be high, this approach still serves to reduce the amount of overall genotyping by about 60%. DNA pooling merits further investigation as a potential strategy in increasing the efficiency of genomic linkage scans.

Alleles↗
PubMed1997

Decompressive bifrontal craniectomy in the treatment of severe refractory posttraumatic cerebral edema.

OBJECTIVE: The management of malignant posttraumatic cerebral edema remains a frustrating endeavor for the neurosurgeon and the intensivist. Mortality and morbidity rates remain high despite refinements in medical and pharmacological means of controlling elevated intracranial pressure; therefore, a comparison of medical management versus decompressive craniectomy in the management of malignant posttraumatic cerebral edema was undertaken. METHODS: At the University of Virginia Health Sciences Center, 35 bifrontal decompressive craniectomies were performed on patients suffering from malignant posttraumatic cerebral edema. A control population was formed of patients whose data was accrued in the Traumatic Coma Data Bank. Patients who had undergone surgery were matched with one to four control patients based on sex, age, preoperative Glasgow Coma Scale scores, and maximum preoperative intracranial pressure (ICP). RESULTS: The overall rate of good recovery and moderate disability for the patients who underwent craniectomies was 37% (13 of 35 patients), whereas the mortality rate was 23% (8 of 35 patients). Pediatric patients had a higher rate of favorable outcome (44%, 8 of 18 patients) than did adult patients. Postoperative ICP was lower than preoperative ICP in patients who underwent decompression (P = 0.0003). Postoperative ICP was lower in patients who underwent surgery than late measurements of ICP in the matched control population. A statistically significant increased rate of favorable outcomes was seen in the patients who underwent surgery compared to the matched control patients (15.4%) (P = 0.014). All patients who exhibited sustained ICP values above 40 torr and those who underwent surgery more than 48 hours after the time of injury did poorly. Evaluation of the 20 patients who did not fit into either of those categories revealed a 60% rate of favorable outcome and a statistical advantage over control patients (P = 0.0001). CONCLUSION: Decompressive bifrontal craniectomy provides a statistical advantage over medical treatment of intractable posttraumatic cerebral hypertension and should be considered in the management of malignant posttraumatic cerebral swelling. If the operation can be accomplished before the ICP value exceeds 40 torr for a sustained period and within 48 hours of the time of injury, the potential to influence outcome is greatest.

Adolescent↗
PubMed1979

[Metabolic investigation of a population of institutionalized epileptics (author's transl)].

77 epileptics receiving a combination of anticonvulsants have been studied. 25(OH)D3 levels were diminished in 38% of the patients, markedly so in 25%. iPTH levels were elevated in 13%. Total, as well as ionized, serum calcium levels were significantly lower in the epileptic patients, as compared with a control population. Serum P, Mg, and plasma total CO2 levels remained unaltered. Alkaline phosphatase levels were increased, as well as gamma-GT levels. A transiliac bone biopsy was performed in 15 patients and histomorphometric studies were achieved on decalcified and undecalcified sections. Osteomalacia was present in 4 out of the 15 cases, hyperosteoidosis in one. Three biological features distinguished the cases with osteomalacia : iPTH levels and alkaline phosphatase values were significantly higher, and serum P levels were significantly lower (all were below 2,4 mg/dl) as compared with the non-osteomalacic patients. In an epileptic population, the serum Ca value is lower than in a control population by 0,5 mg/dl. When in addition the serum P is low (which was a feature of male patients), the danger exists for osteomalacia to develop. The former abnormality is connected with low 25(OH)D3 levels, the primary event, while the latter is probably related to high (secondary) iPTH levels.

Alkaline Phosphatase↗
PubMed1990

Steroid response to adrenocorticotropin stimulation in children with human immunodeficiency virus infection.

To evaluate whether frank or subtle disorders of adrenal steroidogenesis exist in human immunodeficiency virus (HIV)-infected children, the adrenal steroid response to an iv bolus of ACTH-(1-24) (0.25 mg Cortrosyn) was determined. Ten children (six males and four females, aged 7 months to 7.5 yr) were studied. Five underwent repeat testing 3-5 months after initial assessment. Nine patients were classified as P2 or symptomatic according to the Center for Disease Control criteria for HIV infection in children. Eight had failure to thrive, six had opportunistic infections and neurological deficits, and two were receiving ketoconazole at the time of ACTH testing. Only one patient had a neonatally acquired transfusion-related HIV infection. Three of the children died 2-5 months after ACTH testing. All patients had normal or slightly elevated baseline and stimulated cortisol levels compared to the control population. The mean post-ACTH cortisol level was significantly higher than the mean post-ACTH level in the control population. No patient demonstrated an impaired aldosterone response to ACTH. The basal and ACTH-stimulated dehydroepiandrosterone levels were normal. Although individual deoxycorticosterone and corticosterone levels were variable, the mean stimulated deoxycorticosterone and corticosterone levels in the patients were suggestive of a selective defect of the 17-desoxy pathway in the adrenal fasciculata. No changes were noted in the patients' cortisol, dehydroepiandrosterone, and aldosterone responses on repeat ACTH testing. In HIV-infected children we have demonstrated that cortisol and aldosterone synthesis is intact. Thus, the chronic debilitation observed cannot be explained on the basis of adrenal insufficiency. However, a selective deficiency of 17-desoxysteroid hormone production from the adrenal fasciculata may be present.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Function Tests↗