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Short-term persistence of high health care costs in a nationally representative sample of children.

OBJECTIVES: Little is known about the persistence of health care costs in children. Determining whether children with high health expenses continue to have high expenses over time can help in the development of targeted programs and policies to decrease costs, plan equitable health insurance strategies, and provide insights into the effects of costly conditions on families. The objectives of this study were to (1) identify the characteristics of children who are in the top 10th percentile for health costs, (2) investigate whether those in the top percentiles for costs in 1 year continue in the same percentiles the next year, and (3) identify factors that predict whether a child stays in the top percentiles. METHODS: Data from 2 consecutive years (2000-2001) of the Medical Expenditure Panel Survey were analyzed. Changes in a child's position in the expenditure distribution were examined. An estimated multivariate model conditional on insurance was developed to predict the true resource costs of providing services. Statistical analyses, including logistic-regression and multivariate linear-regression modeling, were done to account for the weighted sampling used in Medical Expenditure Panel Survey. RESULTS: A total of 2938 children were included in the survey for both years. In 2000, the top 10% of the children accounted for 54% of all costs. They had a mean total expenditure of 6422 dollars with out-of-pocket expenditures of 1236 dollars; 49% of the children in the top decile in 2000 persisted in the top decile in 2001, whereas 12% dropped into the bottom half. Children who had been in the top 10% in 2000 were 10 times more likely than other children to be in the top 10% for 2001. Other characteristics in 2000 that predicted membership in the top decile for 2001 included age (11-15 and 16-17 years), having any insurance (public and private), being positive on the standardized Children With Special Health care Need screener, and having a functional limitation. CONCLUSIONS: Almost half of the children in the top 10% for costs in 2000 persisted in the top 10% in 2001. Older children, children with special health care needs, and children with functional limitations were more likely to be in the top decile. These findings do not support the belief that black and Latino children who are on Medicaid account for a disproportionate share of costs or expenditures. Because the children who were among the top 10% used health care services in a variety of inpatient, emergency department, outpatient, and ancillary venues, providing care coordination throughout the entire health care system is important to address both the cost and the quality aspects of health care for the most costly children. Targeted programs to decrease expenditures for those with the greatest costs have the potential to save future health care dollars. Assessment of the factors that predict persistence of high expenditures can be used to help in the planning of equitable health insurance strategies such as catastrophic care, carve-outs, reinsurance, and risk adjustment. Clinicians should review regularly the extent of care coordination that they are providing for their high-need and high-cost patients, especially preteens and adolescents. Studies that examine the persistence of expenditures over longer periods and include assessment of quality of care are needed.

Adolescent↗

Persistent asthma in adults: comparison of high resolution computed tomography of the lungs after one year of follow-up.

OBJECTIVE: The aims of this study were to evaluate the role of high resolution computed tomography of the thorax in detecting abnormalities in chronic asthmatic patients and to determine the behavior of these lesions after at least one year. METHOD: Fourteen persistent asthmatic patients with a mean forced expiratory volume in 1-second that was 63% of predicted and a mean forced expiratory volume in 1-second /forced vital capacity of 60% had two high resolution computed tomographies separated by an interval of at least one year. RESULTS: All 14 patients had abnormalities on both scans. The most common abnormality was bronchial wall thickening, which was present in all patients on both computed tomographies. Bronchiectasis was suggested on the first computed tomography in 5 of the 14 (36%) patients, but on follow-up, the bronchial dilatation had disappeared in 2 and diminished in a third. Only one patient had any emphysematous changes; a minimal persistent area of paraseptal emphysema was present on both scans. In 3 patients, a "mosaic" appearance was observed on the first scan, and this persisted on the follow-up computed tomography. Two patients had persistent areas of mucoid impaction. In a third patient, mucus plugging was detected only on the second computed tomography. CONCLUSIONS: We conclude that there are many abnormalities on the high resolution computed tomography of patients with persistent asthma. Changes suggestive of bronchiectasis, namely bronchial dilatation, frequently resolve spontaneously. Therefore, the diagnosis of bronchiectasis by high resolution computed tomography in asthmatic patients must be made with caution, since bronchial dilatation can be reversible or can represent false dilatation. Nonsmoking chronic asthmatic subjects in this study had no evidence of centrilobular or panacinar emphysema.

Adult↗

Persistent jaundice after hepatic porto-jejunostomy in biliary atresia: are the patients' prognoses determined within 3 months after surgery?

Eighteen patients with biliary atresia who showed persistent jaundice after hepatic porto-jejunostomy were studied clinically. It was revealed that: 1) Patients who had abnormally high preoperative values of laboratory data showed persistent jaundice; 2) high portal pressure occurred frequently in patients with persistent jaundice; 3) most patients of persistent jaundice had a history of postoperative cholangitis; 4) in contrast to jaundice-free patients, those with persistent jaundice tended to show elevation in gamma-globulin, TTT and gamma-GTP in the early postoperative period. These results suggest that for patients showing an upward tendency in these laboratory data after surgery, carefully management should be taken, even if the serum bilirubin level continue to decrease.

Adolescent↗

Transition models to assess risk factors for new and persistent trypanosome infections in cattle-analysis of longitudinal data from the Ghibe Valley, southwest Ethiopia.

The objective of this study was to apply transition models to distinguish between factors associated with both incident and persistent trypanosome infections. Data collected from 1561 cattle were analyzed from a long-term study involving 8 herds in which both trypanosome infections (a total of 56,931 cattle sampling-months) and tsetse (Glossina spp.) challenge were monitored monthly from March 1986 to March 1998. Both pour-on and insecticide-target tsetse control programs and mass treatment with diminazene aceturate before tsetse control were associated with significant decreases in both incidence and persistence of trypanosome infection relative to noncontrol periods, as were seasonal and sex effects. The magnitudes of the effects were, however, often different for new and persistent infections. For persistence of infection, there were 2 trends. In general, the duration of infection increased during the study, despite the regular treatment with diminazene aceturate. The transition model had 2 major benefits. The first was to identify an increasing duration of infections with time, taking into account other factors associated with increasing infection risk. The second was to highlight different patterns in the effects of certain factors on new and persistent trypanosome infections.

Age Factors↗

X radiation causes a persistent induction of reactive oxygen species and a delayed reinduction of TP53 in normal human diploid fibroblasts.

Multiple genetic changes are required for the development of a malignant cell. The frequency of such changes in cancer cells is higher than can be explained through random mutation, and it was proposed that a subpopulation of cells develop a persistent mutator phenotype. Evidence for such a phenotype has been observed in mammalian cells after treatment with ionizing radiation. The mechanism that promotes this effect has not been defined, but proposed explanations include increased levels of reactive oxygen species (ROS) in irradiated cells and their progeny. The tumor suppressor TP53 is of prime importance in coordinating the cellular response to damage, and it has been suggested to have a role in regulating the cellular redox state. We investigated the persistence of induced levels of ROS in normal diploid human cells for 1 month after X-ray exposure and the role of TP53 in this oxidant response. X radiation induced an oxidant response that persisted for 2 weeks after exposure in cells with normal TP53 function. ROS levels in cells with abrogated TP53 function were decreased in magnitude and duration. X radiation caused a primary transient induction of TP53 followed by a reinduction of TP53 5 days after irradiation. This reinduction persisted for at least 2 days and coincided with the largest induction of apoptosis. The persistently elevated levels of ROS and delayed reinduction of TP53 reported here are further evidence of the delayed effects of ionizing radiation and add to the growing number of such observations.

Antimycin A↗

Antibiotic sensitivity profiles do not reliably distinguish relapsing or persisting infections from reinfections in cats with chronic renal failure and multiple diagnoses of Escherichia coli urinary tract infection.

Older cats with chronic renal failure (CRF) commonly develop urinary tract infections (UTI). Uropathogenic Escherichia coli (UPEC) is identified as the causal agent of UTI in most affected cats. Infections are often complicated, and UPEC infections may persist or recur in these cats. Antibiotic sensitivity profiles have been used to distinguish relapsing or persisting UTI from reinfection by different clones of the same species. However, the accuracy with which antibiograms discriminate different urinary E coli clones in cats is uncertain. We studied 17 cystocentesis-derived UPEC isolates collected from 5 cats with stable CRF and multiple diagnoses of UTI. UTIs were classified as relapses versus persistent infections or reinfections using antibiograms determined by Kirby-Bauer discs and Etests. Subsequently, clonality of UPEC isolates was determined by pulsed-field gel electrophoresis (PFGE). A comparison of PFGE results with antibiograms indicated that antibiotic resistance patterns varied considerably within several individual E coli clones. Both antibiotic susceptibility tests differentiated between relapsing or persistent infections and reinfections with only 58% overall efficiency. Thus, antibiotic sensitivity profiles cannot be relied upon to distinguish between persisting or relapsing infections as compared to reinfections in cats with CRF and multiple diagnoses of E coli UTI.

Animals↗

Psychobehavioral and immunological characteristics of HTLV-1 carriers and non-carriers with persistently low natural killer cell activity.

OBJECTIVE: To clarify the differences in immunological and psychobehavioral characteristics of HTLV-1 carriers and non-carriers with persistently low natural killer (NK) cell activity. METHODS: The individuals with persistently low NK cell activity were divided into HTLV-1 carriers and non-carriers. NK cell activity, lymphocytic proliferation, lymphocyte subsets (CD4+, CD8+, CD16+, CD20+, CD56+), and psychobehavioral responses were examined. PATIENTS: Of 296 outpatients with physical complaints, 30 patients with persistently low NK cell activity (10 HTLV-1 carriers and 20 HTLV-1 non-carriers) and 20 healthy controls negative for HTLV-1 antibody and with normal NK cell activity were randomly selected. RESULTS: In HTLV-1 carriers with persistently low NK cell activity, no significant differences were observed in NK cell subsets (CD16+ and CD56+) and psychobehavioral responses compared with the healthy controls. In HTLV-1 non-carriers, NK cell subsets were significantly low, and depression, anxiety and fatigue were significantly greater than in healthy controls. CONCLUSIONS: These findings suggest that persistently e low NK cell activity in HTLV-1 carriers might be reduced due to the HTLV-1 infection. On the other hand, the reduction in the NK cell activity in HTLV-1 non-carriers appears a to be related to depression, anxiety, and fatigue.

Adult↗

Clinical implication of persistent ischemic chest pain on admission in patients with late reperfused acute myocardial infarction.

OBJECT: Although previous studies reported that late reperfusion might prevent left ventricular dilation after acute myocardial infarction (AMI), implication of persistent ischemic chest pain on admission remains to be investigated. This study was undertaken to assess the implication of persistent ischemic chest pain on in-hospital outcome and left ventricular function after late reperfused AMI. METHODS AND PATIENTS: We studied 63 patients with a first anterior AMI who underwent percutaneous coronary intervention 6 to 24 hours (11.2+/-4.5 hours) after the onset. Of 63 patients, 48 (76%) had persistent ischemic chest pain on admission. RESULTS: Incidence of in-hospital death, reinfarction or congestive heart failure was similar between the 2 groups. Pretreatment left ventricular ejection fraction and end-diastolic volume were similar between the 2 groups. Predischarge angiography was performed at 17+/-5 days after the onset. Late reperfusion prevented the dilation of left ventricular end-diastolic volume in patients with chest pain (78+/-12 to 75+/-17 ml/m2, p=0.15), but did not in those without (75+/-20 to 93+/-28 ml/m2, p=0.03). A multivariate analysis revealed that absence of persistent ischemic chest pain was an independent predictor of predischarge left ventricular end-diastolic volume >100 ml/m2 (odds ratio 0.10, p=0.04). CONCLUSIONS: Our data demonstrated that absence of persistent ischemic chest pain appears to be a simple and reliable marker which predicts left ventricular dilation after late reperfused AMI.

Chest Pain↗

[Use of prophylactic medication in persistent asthma]

OBJECTIVE: To assess the proportion of patients with moderate or severe persistent asthma who are on prophylactic therapy when first evaluated at a specialized outpatient center. METHODS: Descriptive study of 306 patients with persistent asthma and ages ranging from four to fifteen years old, seen from June/1995 to August/1998, at the Respiratory and Allergic Diseases section of the Child and Adolescent Institute, an outpatient reference center located in the town of Juiz de Fora (MG), Brazil. Data from the Institute's registry, chiefly those related to the use of prophylactic medications, such as inhaled steroids, sodium chromoglycate, nedocromil sodium, sustained-release theophylline, long acting inhaled beta2-agonist and ketotifen were used to fill in a standardized protocol. RESULTS: Of the 306 patients, 87.3% had persistent moderate and 12.7% had persistent severe asthma. Only 14.4% were on some kind of controller medication. When only the use of inhaled antiinflammatory drugs (sodium cromolyn, nedocromil sodium and steroids) was considered, this proportion decreased to 4.6%. There was not statistical significance (p<0.05) between the use or not of prophylactic regimens in relation to gender, weight, height, asthma severity, hospital admissions, age of onset, age when first evaluated at the outpatient center and household smoking. CONCLUSIONS: The rate of utilization of prophylactic regimens in this population of persistent asthmatic patients was unsatisfactory, a finding particularly stressed by the low rate of subjects on inhaled antiinflammatory drugs. It is necessary to emphasize such measures to face the magnitude that asthma represents in our country.

Journal Article↗

[Persistent hyperinsulinemic hypoglycemia of infancy: case report]

OBJECTIVE: To report a case of Persistent Hyperinsulinemic Hypoglycemia in twins which is a situation not yet reported in the literature. METHODS: Report of seizures in identical twins, from consanguineous parents, with persistent hypoglycemia as cause of the seizures. Laboratory tests, performed for etiological investigation of the hypoglycemia, included thyroid hormones (T4/TSH), insulin, cortisol, growth hormone, stimulation test with glucagon (to evaluate the insulin/glucose relation), and histopathological study of the pancreas. RESULTS: Laboratorial investigation revealed a persistent hypoglycemia with hyperinsulinism which were confirmed with the stimulation test with glucagon. The histopathological exam showed a persistence of first generation pancreatic islet, confirming the diagnosis of Persistent Hyperinsulinemic Hypoglycemia in Infancy (the new denomination of Nesidioblastosis). CONCLUSION: Although rare, this condition must be early suspected early in the evaluation of hypoglycemia of the young infant, even out of the neonatal period, specially if the parents are consanguineous. The adequate therapy must be quickly initiated in order to prevent neurological damage.

Journal Article↗

Epidemiology of persistent proteinuria in type II diabetes mellitus. Population-based study in Rochester, Minnesota.

Clinical risk factors for nephropathy were assessed in a population-based study of Rochester, Minnesota, residents with diabetes mellitus initially diagnosed between 1945 and 1969 (incidence cohort). The 1031 Rochester residents with non-insulin-dependent diabetes mellitus (NIDDM) were followed through their complete medical records in the community to 1 January 1982. The prevalence of persistent proteinuria was 8.2% at the diagnosis of NIDDM. Among those initially free of persistent proteinuria, the subsequent incidence was 15.3/1000 person-yr. Twenty years after the diagnosis of diabetes, the cumulative incidence of persistent proteinuria was 24.6%. A proportional hazards model identified the following risk factors for persistent proteinuria in NIDDM: elevated initial fasting blood glucose (P less than .01); older age at onset of diabetes (P less than .01); male gender (P = .05); and presence of macrovascular disease (P = .05), diabetic retinopathy (P = .05), or glycosuria (P = .07) at the diagnosis of diabetes. Separate analyses controlling for attained age indicated no association between duration of NIDDM and the incidence of persistent proteinuria. Stratified analysis of the two most significant risk factors (fasting blood glucose and age) indicated that hyperglycemia was a stronger risk factor for proteinuria in younger diabetic subjects, perhaps because of a competing risk of death in the elderly diabetic patient. In contrast to a recently described decreasing secular trend of proteinuria in Danish insulin-dependent diabetes mellitus patients, there was no decrease over the past 40 yr in proteinuria risk in this NIDDM incidence cohort.

Adult↗

Cognitive function in an elderly population with persistent impaired glucose tolerance.

OBJECTIVE: To study cognitive function in an elderly population with persistent impaired glucose tolerance (IGT). RESEARCH DESIGN AND METHODS: Fasting and postload 2-h plasma glucose and insulin levels were determined at baseline in a population-based sample of 1,300 people and repeated an average of 3.5 years later in 980 subjects. At follow-up, cognitive function was evaluated in subjects with persistent normal glucose tolerance (NGT; n = 506) and IGT (n = 80) with a brief neuropsychological test battery. RESULTS: Subjects with persistent IGT scored lower in the Mini-Mental State Examination (MMSE) and in the Buschke Selective Reminding Test long-term memory scores. Multiple linear regression analysis revealed that age, education, and insulin levels (either fasting or 2-h value) were associated with the MMSE score in subjects with persistent IGT. Other potential risk factors for impaired cognitive function were not significantly associated with the MMSE score. CONCLUSIONS: Our study showed that persistent IGT in the elderly is associated with mildly impaired cognitive function, and hyperinsulinemia may account for this association.

Age Factors↗

Acute progesterone administration regresses persistent dominant follicles and improves fertility of cattle in which estrus was synchronized with melengestrol acetate.

Experiments were conducted to determine whether acute progesterone administration would regress persistent follicles and improve fertility in heifers and postpartum cows fed melengestrol acetate (MGA). In Exp. 1, heifers (n = 13) were fed MGA for 11 d (1st d of MGA = d 1). Prostaglandin F2 alpha (PGF2 alpha) was administered to heifers on d 2 to regress the corpus luteum (CL). On d 9, heifers were randomly assigned to receive an injection of either 200 mg of progesterone (PROG) or no hormone (vehicle; VEH). Neither growth of the persistent follicle nor plasma estradiol concentrations were altered by administration of VEH, and the persistent follicle ovulated after cessation of MGA feeding. Administration of PROG regressed the persistent follicle, reduced (P < .05) systemic estradiol concentrations, and resulted in ovulation of a newly recruited follicle. In Exp. 2, heifers were fed MGA for 14 d and were administered either PROG (n = 30) or VEH (n = 31) on d 12. When the CL was absent on d 12, synchronization conception rate (SCR) and pregnancy rate (PR) were greater (P < .05) for heifers administered PROG than for those administered VEH. Neither SCR nor PR were different among treatments when the CL was present on d 12. In Exp. 3, cows (n = 49) were fed MGA for 14 d and were administered either PROG or VEH on d 12. In cows lacking a CL (n = 32), administration of PROG increased (P < .05) SCR, but not PR. We conclude that acute PROG administration induces turnover of persistent follicles and may increase fertility when estrus is synchronized with MGA.

Animals↗

Persistence of the dominant follicle during melengestrol acetate administration and its regression by exogenous estrogen treatment in beef cattle.

Experiments were conducted to test the hypothesis that estrogen treatment will regress a persistent dominant follicle developed during melengestrol acetate (MGA) treatment in the absence of a functional corpus luteum (CL) with normal fertility following development and ovulation of a newly recruited follicle. In Exp. 1, nonlactating beef cows (n = 31) were administered .5 mg.cow-1.d-1 of MGA (d 0) for 14 d with 25 mg of prostaglandin F2 alpha (PGF2 alpha) administered on d 6 and 8 to regress the CL. On d 11 of treatment, approximately half the MGA-treated cows received 5 mg of estradiol valerate (EV) i.m. (MGAEV, n = 14) and the remainder were maintained on MGA (n = 17). Ovaries were checked with ultrasound on d 8, 10, 12, and 14 of MGA treatment and every day until ovulation. A persistent dominant follicle developed in 90% of the MGA-treated cows by d 10 of treatment. Most of the MGA-treated cows ovulated the persistent dominant follicle (n = 13/17), whereas EV treatment regressed the persistent dominant follicle (n = 10/14) with the recruitment of a new follicle that ovulated (n = 8/10). Diameter of the ovulatory follicle was larger (P < .05) for the MGA (19.8 +/- .6 mm) than for the control (15.1 +/- .8 mm) and MGAEV (14.8 +/- .7 mm) cows. In Exp. 2, nonlactating, multiparous beef cows (n = 97) and yearling heifers (n = 38) were equally allotted to either a control, MGA alone, or MGA + estradiol-17 beta (MGAE) group with the same dose of MGA as administered in Exp. 1. The 1st d of MGA feeding was the 1st d of treatment. On d 10 of treatment half the MGA-treated animals were injected i.m. with 5 mg of estradiol-17 beta. In controls, behavioral estrus was detected and animals were artificially inseminated (AI) for 5 d (d 10 to 14 of experiment). All controls not exhibiting estrus by d 15 of experiment were injected with 25 mg of PGF2 alpha. The remaining controls and all MGA cows were observed for behavioral estrus and AI commenced for 7 d following withdrawal of MGA (d 15 to 21 of experiment). More (P < .05) controls (90.3%) than MGA (84.8%) or MGAE (63.6%) cows showed estrus within 7 d after MGA withdrawal. The percentage of animals conceiving to the synchronized estrus did not differ (P > .05) among treatments. The data support our hypothesis that a persistent dominant follicle developed and can be regressed with exogenous estrogen treatment followed by the recruitment and ovulation of a new follicle after MGA withdrawal and fertility of that estrus does not seem to be significantly compromised.

Animals↗

Duration of treatment with progesterone and regression of persistent ovarian follicles in cattle.

The objective of the present study was to determine the duration of elevated concentrations of progesterone necessary to induce atresia of persistent ovarian follicles. Heifers were administered 25 mg of PGF2alpha on d 6 and 7 (d 0 = d of synchronized estrus) and a norgestomet implant from d 6 to 14. Ovaries were monitored by ultrasonography, and blood samples were collected on d 3, 5, 7, 9, 11, and 12 and daily from d 14 until ovulation. On d 12, heifers received either two progesterone-releasing intravaginal devices (PRID) for 6 h (6-h; n = 5), two PRID for 24 h (24-h; n = 5), or no treatment (CON; n = 5). Blood samples were collected at 15-min intervals from h -6 to 30 (PRID insertion = h 0) and analyzed for concentrations of LH. Characteristics of LH secretion were determined for consecutive 6-h periods (Period 0 to 5). Hourly blood samples, collected from h 0 to 29, were analyzed for concentrations of 17beta-estradiol (estradiol) and progesterone. The dominant ovarian follicles present on d 7 increased in size to 15.4+/-.3 mm on d 12 ("persistent follicle"). Following removal of the PRID and norgestomet implants, atresia of persistent follicles and ovulation of new follicles were induced in one of five and in four of five heifers in the 6-h and 24-h treatments, respectively. Persistent follicles ovulated after withdrawal of norgestomet in all other heifers. Concentrations of progesterone were increased from h 1 to 7 in the 6-h and h 1 to 26 in the 24-h treatment. Frequency of LH pulses was reduced (P < .05) during Periods 1 to 2 in the 6-h and Periods 1 to 5 in the 24-h treatment relative to the CON treatment. By h 10, concentrations of estradiol in the 6-h and 24-h treatments were lower (P < . 05) than in the CON treatment. This suppression continued through h 29 in the 24-h treatment (P < .05), whereas concentrations in the 6-h treatment were intermediate to those of the CON and 24-h treatments after h 14. Suppression of pulsatile LH release and estradiol secretion was evident with 6 and 24 h of treatment with progesterone, but only the 24-h treatment induced atresia of persistent follicles in a majority of the heifers.

Administration, Intravaginal↗

Parvovirus B19 infection--persistence and genetic variation.

53 patients with acute B19 infection were studied; symptoms at acute infection were rash and arthralgia (n = 26), rash (n = 7), arthralgia (n = 16), aplastic crisis (n = 3), and intrauterine fetal death (n = 1). These patients were followed for 26-85 months (mean 57 months) and re-assessed for persistent symptoms, anti-B19 antibodies, and B19 DNA. At follow-up, 7 individuals were positive for serum B19 DNA, compared with none of the controls (2-tailed p value = 0.016). All 7 of those persistently infected were women, 3 of whom had symptoms; 1 had a chronic haemolytic anaemia (initial presentation was aplastic crisis); 1 had persistent arthralgia in both knees (initial presentation was bilateral knee arthralgia); and 1 had arthralgia in one knee and chronic fatigue syndrome (initial presentation was bilateral arthralgia in knees and shoulders). For the 7 persistently infected patients, serum from the time of diagnosis of acute B19 infection was available for 4, all of which contained B19 DNA. With single-stranded conformational polymorphism (SSCP) assay of these 11 PCR products, identical SSCP types were demonstrated in 5 of 7 follow-up isolates. In 2 of the 4 cases for which both acute and follow-up PCR product was available, the SSCP type of the follow-up product was different from that of the acute product. Two B19 virus types were demonstrated in one patient (with persistent arthralgia and chronic fatigue syndrome) at follow-up assessment.

Adolescent↗

Inter-relationship of sympathetic nervous system and renin-angiotensin-aldosterone system in three renin subgroups of borderline and persistent essential hypertension.

Plasma renin activity (PRA), dopamine beta-hydroxylase (DBH) activity, and plasma aldosterone concentration were determined in 51 patients categorized as borderline or persistent hypertensives and as high, normal, or low renin. Basal DBH activity correlated with diastolic blood pressure in borderline but not in persistent hypertensives. In borderline patients with normal or high renin activity standing plus furosemide caused a marked rise in diastolic blood pressure but little change in systolic and increased PRA and DBA. In contrast this stimulation procedure depressed both systolic and diastolic blood pressure and resulted in blunted PRA and DBH responses in the low renin borderline and the three groups of persistent hypertensives. After dietary sodium restriction, the decrease in systolic blood pressure correlated with the decrease in urinary sodium excretion in persistent, but not in the borderline patients. The data suggest that both borderline an persistent hypertensive patients respond to volume depletion with an increase in sympathetic and renin activity, and the increase of these two vasoconstrictive systems is greater in borderline hypertensives.

Adult↗

Use of multivariate analysis to extract latent variables related to level of production and lactation persistency in dairy cattle.

Multivariate factor analysis and principal component analysis were used to decompose the correlation matrix of test-day milk yields of 48,374 lactations of 21,721 Italian Simmental cows. Two common latent factors related to level of production in early lactation and lactation persistency, and 2 principal components associated with the whole lactation yield and persistency were obtained. Factor and principal component scores were treated as new quantitative phenotypes related to prominent features of lactation curve shape. Genetic parameters were estimated by univariate and bivariate animal models. Estimates of heritability were moderately low for both latent factors (0.13 for persistency and yield early in lactation). Heritabilities of the principal component related to total lactation yield and 305-d yield were similar (0.19 and 0.20, respectively). Finally, heritability was quite low for the principal component related to lactation persistency (0.07). Repeatabilities between lactations were about 0.27 for both latent factors, around 0.4 for the first principal component and 305-d yield, and 0.11 for the second principal component. Moderate genetic correlation among common factors (0.26) and their high genetic correlation with total lactation yield (>0.60) suggest that selection can be used to change the shape of lactation curve as well as improve yield. Scores of the second principal component can be used to genetically improve persistency while maintaining constant total lactation yield.

Analysis of Variance↗