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PubMed1991

Serum human chorionic gonadotropin concentration for predicting multiple gestation in pregnancies conceived with superovulation and intrauterine insemination.

Assisted reproductive technologies are associated with an increased incidence of multiple gestation. Because they provide precise information on the time of ovulation, those technologies afford an opportunity to analyze the association between multiple gestation and maternal serum human chorionic gonadotropin (hCG) concentrations during early pregnancy. We retrospectively evaluated this association in 76 pregnancies (26 multiple) conceived with superovulation and intrauterine insemination. Using multiple linear regression, we discerned that the number of fetuses surviving the first trimester was directly proportional to the log of the hCG concentrations. The mean + 1 SD for the estimated hCG values of singleton pregnancies was selected a priori as the threshold for detecting multiple pregnancies. This threshold value provided a sensitivity of 73%, specificity of 80% and overall accuracy of 78%. Nine of 11 pregnancies with three or more fetuses had hCG concentrations above the threshold values. Although there is a positive correlation between the number of fetuses surviving the first trimester and the hCG concentration early in pregnancy, the predictive value of the hCG concentration is useful only for excluding most triplet and quadruplet pregnancies.

Chorionic Gonadotropin↗

PubMed1987

Biophysical and microbiologic studies of "heavy" and "light" plaque formers.

In order to trace factors possibly influencing initial bacterial colonization of tooth surfaces, a multiple linear regression analysis was performed on the present results as well as on those from certain clinical and biochemical studies previously performed in the same subjects. No statistically significant differences were observed between the two groups of plaque formers for the individual parameters. The multiple regression analysis showed, however, that the calculated work of adhesion for two polar and one non polar test liquid, the rate of unstimulated salivary secretion, morphologic differences in the dento-gingival areas of maxillary premolars and saliva-induced aggregation of S. mitior were crucial for about 90% of the variation in the number of CFU colonizing tooth surfaces after both 2 and 6 h. Both electrostatic and van der Waal's forces, as well as salivary flow conditions could thus have influenced the initial attachment of bacteria to the test surfaces. It is concluded that saliva including its suspended microorganisms could be looked upon as being a colloidal biological system, and if so, the initial bacterial colonization of tooth surfaces should follow known, general biophysical laws.

Adhesiveness↗

PubMed1993

[Factors associated with at-risk anal relations in homosexual HIV-seropositive men].

This pilot study proposes an index to quantify the intensity of high-risk anal sex and presents factors associated with this practice among 65 homosexual men with HIV infection. All of them answered a self-administered questionnaire. Using multiple logistic regression, we first compared those who had had safe sex in the past six months to those who had had unsafe sex. Variables significantly associated with unsafe sex are: drugs and/or alcohol use with sex, and less favorable attitude towards condom use. Finally, multiple linear regression analysis among respondents who had had unsafe sex indicated that the following factors are associated with higher levels of unsafe sex: men between the ages of 32 and 38, satisfied with their social life, non-smokers, with a less favorable attitude towards condom use, and with few social relationships. These results must be interpreted with caution because of the small number of respondents.

Attitude↗

PubMed1991

A multivariate analysis of risk factors for anterior atlantoaxial subluxation and an evaluation of the effect of glucocorticoid treatment on the upper rheumatoid cervical spine.

A cross-sectional, retrospective computerized analysis of risk factors for anterior atlantoaxial subluxation (AAS) was performed. Logistic regression performed on the clinical variables involved in 145 cases of rheumatoid arthritis (RA) disclosed a high joint score index and a low blood haemoglobin level as significant independent risk factors. This means that the development of anterior AAS is connected with widespread RA. Linear multiple regression analysis showed an association between the extent of anterior AAS in millimetres and the spread of erosions of the dens of axis and negative correlation with the severity of vertical atlantoaxial dislocation (VD). This suggests that whereas the presence of anterior AAS is connected with the severity of the systemic disease, its actual extent is associated with signs of local involvement, other than severe VD. The duration or cumulative dosage of glucocorticoids were not associated with the development or extent of anterior AAS, nor with the severity of vertical dislocation. This suggests that low dose glucocorticoid treatment is not involved with the development of rheumatoid changes in the upper cervical spine. It should be borne in mind, of course, that although no correlation was found, a causal relation cannot be excluded.

Arthritis, Rheumatoid↗

PubMed2001

Chronic hyperlactatemia in HIV-infected patients taking antiretroviral therapy.

OBJECTIVE: To determine the prevalence, course and risk factors for hyperlactatemia in HIV-infected patients. DESIGN: A prospective, longitudinal study of venous lactate concentrations over an 18-month period in 349 participants of the Western Australian HIV Cohort Study. RESULTS: In 516 patient-years of observation, two patients experienced severe fulminant lactic acidosis (lactate > 5 mmol/l) and hepatic steatosis attributable to nucleoside analogue reverse transcriptase inhibitors (NRTI). A further five patients with lesser elevations of lactate (2.8-4.1 mmol/l) but with symptoms of nausea or abdominal discomfort and evidence of hepatic steatosis had NRTI therapy revised, with relief of symptoms and a fall in lactate levels. Most remaining patients on highly active antiretroviral therapy (HAART) had mild, chronic, asymptomatic hyperlactatemia, with mean lactate level between 1.5 mmol/l and 3.5 mmol/l most commonly. Longitudinal data was analysed in a non-linear mixed effects growth model which indicated that average lactate levels rose after the start of HAART but tended to stabilise at low-grade elevation, with an average 0.23 mmol/l greater long term level in stavudine users compared with zidovudine users (p < 0.01). A multiple linear regression model showed that the association between stavudine and higher lactate level was not confounded by longer duration of total NRTI exposure. Risk of hyperlactatemia was not significantly associated with use of other NRTIs, protease inhibitors, non-nucleoside analogue reverse transcriptase inhibitors or multiple immunological and virological factors in multivariate analyses. CONCLUSIONS: Chronic, compensated, asymptomatic hyperlactatemia is common in patients taking HAART. Decompensated, life-threatening lactic acidosis/hepatic steatosis is rare. Treatment with stavudine appears to be the predominant risk factor for development of chronic hyperlactatemia.

Acidosis, Lactic↗

PubMed2003

Simulation of aerated lagoon using artificial neural networks and multivariate regression techniques.

The aim of this study was to develop an empirical model that provides accurate predictions of the biochemical oxygen demand of the output stream from the aerated lagoon at International Paper of Brazil, one of the major pulp and paper plants in Brazil. Predictive models were calculated from functional link neural networks (FLNNs), multiple linear regression, principal components regression, and partial least-squares regression (PLSR). Improvement in FLNN modeling capability was observed when the data were preprocessed using the PLSR technique. PLSR also proved to be a powerful linear regression technique for this problem, which presents operational data limitations.

Biotechnology↗

PubMed1989

Influence of leukopenia on collateral flow, reperfusion flow, reflow ventricular fibrillation, and infarct size in dogs.

Leukocytes contribute to myocardial damage during ischemia and reperfusion. However, the mechanism involved has not been clearly elucidated. The purpose of the present study was to determine whether leukocyte-induced myocardial damage is flow mediated. In open-chest dogs submitted to 2 hours of ischemia, area at risk, infarct size, and regional myocardial blood flow before, during, and after ischemia were measured. Leukopenia was induced by a two-step method (chemotherapy and antineutrophil serum) in a group of 14 dogs as compared to a control group of 18 dogs. The relation of infarct size to the major determinants of infarct size was analyzed by uni- and multilinear regressions. Seven control dogs had ventricular fibrillation at reperfusion compared to one dog with leukopenia. In the group with leukopenia the mean infarct size was smaller (31.1 +/- 5.8% of area at risk) than in the control group (47.7 +/- 2.9, p = 0.02). In addition, the two multiple linear regression equations were significantly different (p = 0.01). Myocardial blood flow to the central ischemic zone did not change significantly between 20 and 120 minutes of ischemia in the control dogs (n = 12; subendocardial = 0.08 +/- 0.03 vs 0.07 +/- 0.03 ml/min/gm; subepicardial = 0.20 +/- 0.07 vs 0.20 +/- 0.05 ml/min/gm) and in the dogs with leukopenia (n = 12; 0.07 +/- 0.02 vs 0.07 +/- 0.02 ml/min/gm and 0.15 +/- 0.004 vs 0.18 +/- 0.04 ml/min/gm). A similar reduction in myocardial blood flow was observed after 6 hours of reperfusion in the control dogs (0.34 +/- 0.07 ml/min/gm vs 1.02 +/- 0.11 at baseline, p less than 0.01) and in the dogs with leukopenia (0.25 +/- 0.04 vs 0.81 +/- 0.08 ml/min/gm, p less than 0.01). It was concluded that the leukocyte-dependent myocardial injury did not appear to be mediated through a flow mechanism during either ischemia or reperfusion.

Animals↗

PubMed1996

Composite versus multiple-rating scales in the assessment of psychopathology in people with mental retardation.

This study tested the hypothesis that separate ratings of frequency and duration add significant information to ratings of problem severity in the assessment of psychopathology in people with mental retardation. The Reiss Screen was modified to require ratings of problem severity, frequency and duration for each of 38 maladaptive behaviours. The 171 adolescents and adults were rated by caretakers and supervisory staff on the modified Reiss Screen. The three ratings were found to be very highly intercorrelated. Moreover, multiple linear regression analyses revealed that the ratings of frequency and duration did not add significant information to that provided by ratings of problem severity in the prediction of psychiatric diagnosis in the person's case file. The results support the use of composite scaling over multiple-ratings in the assessment of psychopathology in persons with mental retardation.

Adolescent↗

PubMedDate not supplied

The inverse relationship between bone status and blood pressure among Polish men.

PRIMARY OBJECTIVE: An evaluation of relationships between bone density and blood pressure in healthy men. RESEARCH DESIGN: A cross-sectional population-based survey. METHODS AND PROCEDURES: An ethnically homogeneous sample of 208 men, aged 35-63, healthy and occupationally active inhabitants of the city of Wroclaw, Lower Silesia, Poland were studied. Trabecular, cortical and total bone mineral content (BMC) at the ultra-distal radius of the non-dominant hand were assessed by peripheral Quantitative Computed Tomography (pQCT: Stratec 960 apparatus). Body mass index (BMI) was used as a measure of general obesity. Systolic and diastolic blood pressure (BP) were measured using an MPC-350 sphygmomanometer. Multiple linear regression was used to evaluate the relationships between BP and BMC. A two-way analysis of covariance was carried out to test for the significance of inter-group differences in BMC with regard to age and BP with BMI as a contiuous covariable. Multiple logistic regression was used to verify whether some select factors (age, BMI, systolic and diastolic BP) could significantly predict male bone status. RESULTS: Systolic BP was not related to bone status at the ultra-distal radius. There were no differences in any BMC between systolic hyper- and normotensive subjects. Additionally, systolic hypertension did not affect the probability of an occurrence of male osteopenia (independently of age and BMI). In contrast, there were significant negative relationships between diastolic BP, and trabecular and total (but not cortical) BMC (even when controlled for age and BMI). Moreover, diastolic hypertensive men had reduced BMC at the ultra-distal radius when compared with normotensive subjects. It is noteworthy that Polish men of diastolic BP exceeding 90 mmHg had an approximately 1.50-fold increased relative risk of being osteopenic when compared with normotensive subjects (even when controlled for age, BMI and systolic BP). CONCLUSIONS: In the light of the inverse relationship between BMC and diastolic BP, Polish men with elevated diastolic BP seem to be more prone to the excessive age-related bone loss.

Adult↗

PubMed2002

Analysis of drug prescription in chronic haemodialysis patients.

BACKGROUND: Information concerning medication use in Asian haemodialysis patients is sparse. We surveyed prescribed medications and examined the relation between the number of medications and mortality and clinical characteristics in chronic haemodialysis patients, in Okinawa, Japan. METHODS: We conducted a cross-sectional multicentre survey in August 1999 and patients were observed during 13 months of follow up. RESULTS: The clinical demographics of 850 chronic haemodialysis patients in seven dialysis units were obtained. Compared with the mean number of medications prescribed in ambulatory patients treated in general practice reported from Ministry of Health and Welfare of Japan (2.7 (n=20 716)), the mean number medications in haemodialysis patients was larger (7.2 (n=850)). The three most prescribed drug types in haemodialysis patients were those related to calcium and phosphate metabolism (88%), antihypertensive agents (71%), and erythropoietin (60%). Among the 850 patients, 38 died during the 13-month follow-up period. The number of medications was positively associated with mortality after adjusting for age, sex, and other clinical factors: the hazard ratio was 1.14 (95% confidence interval 1.03-1.26, P=0.007). A multiple linear regression analysis using the number of medications as a dependent factor and sex and other clinical characteristics as independent factors revealed that male sex (P=0.04), diabetes mellitus (P<0.0001), and duplication of drugs (P<0.0001) were positively correlated with the number of medications. CONCLUSIONS: Multiple drug use was observed in haemodialysis patients. The number of prescribed drugs was a significant predictor of short-term mortality. Male sex, diabetes mellitus, and duplication of drugs were correlated with increases in the number of medications.

Adult↗

PubMed2006

Pre-operative measurement of heart rate variability predicts hypotension during general anesthesia.

BACKGROUND: Peri-operative hymodynamic instability is one of the major concerns for anesthesiologists when performing general anesthesia for individuals with autonomic dysfunction. The purpose of this study was to examine the potential usage of pre-operative measurement of heart rate variability (HRV) in identifying which individuals, with or without diabetes, may be at risk of blood pressure (BP) instability during general anesthesia. METHODS: We studied 46 patients with diabetes and 87 patients without diabetes ASA class II or III undergoing elective surgery. Participants' cardiovascular autonomic function and HRV were assessed pre-operatively, and hymodynamic parameters were monitored continuously intra-operatively by an independent observer. RESULTS: Only 6% of the participants were classified as having cardiovascular autonomic neuropathy (CAN) based on traditional autonomic function tests whereas 15% experienced hypotension. Total power (TP, P = 0.006), low frequency (LF, P = 0.012) and high frequency (HF, P = 0.028) were significantly lower in individuals who experienced hypotension compared with those who did not. Multivariate logistic regression analysis revealed that TP [odds ratio (OR) = 0.15, 95% confidence interval (CI) = 0.05-0.47, P = 0.001] independently predicted the incidence of hypotension, indicating that each log ms2 increase in total HRV lowers the incidence of hypotension during general anesthesia by 0.15 times. After stepwise multiple linear regression analysis (R2= 11.5%), HF (beta = -11.1, SE = 2.79, P < 0.001) was the only independent determinant of the magnitude of systolic blood pressure (SBP) reduction at the 15th min after tracheal intubation. CONCLUSIONS: Spectral analysis of HRV is a sensitive method for detecting individuals who may be at risk of BP instability during general anesthesia but may not have apparent CAN according to traditional tests of autonomic function.

Adult↗

PubMed1982

Factors in predicting blood pressure change.

A total of 1166 male participants (ages 23--80 years) of the Normative Aging Study who had baseline blood pressure less than 140/90 mm Hg were followed prospectively for 10 years. Blood pressures were taken at 5- and 10-year follow-up examinations. Multiple linear regression analysis indicated that baseline levels of systolic pressure, hematocrit, subscapular skinfold thickness and age were significant predictors of systolic pressure change during the follow-up period. Baseline levels of diastolic pressure, hematocrit, and body mass index were significant predictors of diastolic pressure change. Multiple logistic regression analysis revealed that only baseline blood pressure and hematocrit were significant predictors of subsequent blood pressure elevation to more than 159 mm Hg systolic or 94 mm Hg diastolic. Although the mechanisms by which hematocrit and body build affect blood pressure are unknown, these results suggest that identifying hypertension-prone subjects and delaying or preventing hypertension may be possible.

Adult↗

PubMed2006

[Predicted vales of respiratory function tests in young Japanese aged from 10 to 20 years].

To find predicted values of respiratory function tests in young persons in Japan, we measured slow vital capacity and forced vital capacity in 1,141 subjects aged from 10 to 20 years. The values obtained from 636 persons (363 males and 273 females) who were not smokers or had no suspected rhinitis or asthma were analyzed. Although FEV1% by the Gaensler and Tiffeneau methods were almost constant regardless of age, all other values of respiratory function tests increased with age and then reached a plateau level in late teens. Excluding the Gaensler and Tiffeneau FEV1%, in a single regression analysis using gender, age, and height, both the contribution ratio and regression coefficient were the highest using height, followed by age. In addition, the result was similar with multiple regression analysis. Therefore, for a young person aged from 10 to 20 years, body height is the most important predictor variable of respiratory function tests, compared to gender and age. For each respiratory function test, we showed the prediction relation according to gender obtained from multiple linear regression analysis using 2 variables of height and age.

Adolescent↗

PubMed1989

Improved method for calculating calcium fractions in plasma: reference values and effect of menopause.

Multiple linear regression analysis showed that total calcium was significantly and positively related to albumin, globulin, anion gap, and bicarbonate in plasma from 556 normal postmenopausal women. The residual constant of 1.21 mmol/L approximated the normal mean for ionized calcium in plasma. The coefficients derived from the multiple regression analysis were used to calculate ionized calcium from total calcium and ligand concentrations in a series of 105 clinical cases in whom ionized calcium was measured with the calcium electrode. The regression equation was y = 1.00x -0.0039 mmol/L, where x is measured and y calculated Ca2+ (r = 0.78, P less than 0.001). The protein-bound, ultrafiltrable, and complexed fractions of the calcium were also calculated for plasma from 69 normal young men, 66 normal young women, and 305 normal postmenopausal women. The increased plasma calcium in the postmenopausal group was accounted for by an increase in the complexed fraction, due to increases in plasma bicarbonate and anion gap.

Adult↗

PubMed1997

The effect of positive and negative health behavior during gestation on pregnancy outcome.

This study examined the effects of substance use (alcohol, tobacco and/or drugs (cocaine and/or marijuana)) and healthy maternal behavior (prenatal care, prenatal class, vitamins, regular exercise) during gestation on pregnancy outcome. Live births from the nationally representative 1988 National Maternal and Infant Health Survey were analyzed. Pregnancy outcomes (infant birth weight, weeks gestation, one and five minute Apgar scores, whether or not the infant was transferred to another hospital after delivery and whether or not the infant was rehospitalized) were studied in multiple linear regression and logistic regression models. The relationship of the interaction of substance use and healthy behaviors and outcome was studied in all models. It was found that women engaging in substance use while pregnant were less likely to engage in healthy behavior. However, in general, engaging in healthy behaviors had the largest positive effects on outcome for those women who engaged in multiple substance use while pregnant. Significant interactions between healthy and unhealthy behavior were found for birth weight, weeks gestation and five minute Apgar scores, indicating that engaging in positive health behavior may help moderate some of the deleterious consequences of substance use during pregnancy.

Adult↗

PubMed1985

Predicting severity of liver disease: twelve laboratory tests evaluated by multiple regression.

To determine the predictive value of laboratory procedures for severity of liver disease, twelve laboratory tests were evaluated in seventy-two patients with various liver disease and in nine non-liver disease hospitalized cases. A numerical score based on the number and extent of abnormal findings was developed for grading clinical and histological severity. Multiple linear regression, utilizing a forward stepwise selection procedure, was used to find the best combination of laboratory tests for prediction of disease severity. The best predictive model for both clinical and histological severity was found for lecithin cholesterol acyltransferase (LCAT), total plasma cholesterol, alkaline phosphatase and bile acids. Of the routine tests prothrombin time and albumin/globulin were useful if the four-test combination listed above was not used. There was a significant correlation (p less than 0.001) between the clinical and the histological score, confirming validity of clinical scoring. In conclusion, this study shows LCAT to rank as first in predicting severity of liver disease. Cholesterol metabolism appears to be affected by liver disease even more than prothrombin time, albumin and globulins. LCAT and bile acids have a place in routine testing of severity of liver disease.

Adult↗

PubMed1993

Coronary embolization after balloon angioplasty or thrombolytic therapy: an autopsy study of 32 cases.

OBJECTIVES: This study was undertaken to examine the nature, extent and clinical relevance of coronary embolism after balloon angioplasty or thrombolytic therapy, or both. BACKGROUND: Histopathologic documentation of postinterventional coronary embolization has been reported in only 10 patients from five studies. METHODS: This retrospective autopsy-based study included 32 patients, treated with balloon angioplasty or thrombolysis, or both, who died within 3 weeks of the procedure and underwent autopsy at the Mayo Clinic. Clinical variables included patient age and gender, artery treated, site and type of obstruction, type of intervention, success of the procedure, and postprocedural changes in the electrocardiogram (ECG), cardiac enzymes and hemodynamic status. Histopathologic variables included characteristics of treated plaques, acutely infarcted myocardium and coronary microemboli. Associations between microemboli and clinical and microscopic factors were evaluated by t tests and simple and multiple linear regression. RESULTS: Emboli were observed in 26 (81%) of the 32 patients. Among 83 emboli, 95% were thrombotic or atheromatous. The presence of microemboli was associated statistically with the development of postprocedural infarct extension, new myocardial infarction or new ECG abnormalities. Moreover, the greatest number of microemboli were associated with intervention in the left anterior descending coronary artery, multiple interventional sites, postprocedural medial dissection and plaque rupture or extrusion. CONCLUSIONS: Among patients undergoing balloon angioplasty or thrombolytic therapy who die and undergo autopsy, coronary microemboli occur in a substantial percent. The frequency in survivors is unknown. However, in living patients who develop acute myocardial ischemia or new ECG abnormalities after these interventions, coronary microembolization should be considered a potential cause.

Adult↗

PubMed2002

Socioeconomic and psychosocial factors influence pain or physical function in Asian patients with knee or hip osteoarthritis.

OBJECTIVE: To determine factors influencing pain or physical function in Asian patients with osteoarthritis (OA). METHODS: 126 consecutive Chinese (110), Malays (two), Indians (10), or other races (four) with knee or hip OA and a median age of 60.5 years were seen at a tertiary referral centre; 103 were women. Subjects underwent a structured assessment including the Short Form-36 (SF-36) bodily pain (BP) and physical functioning (PF) scales and assessing demographic, socioeconomic, psychosocial, and other characteristics. Factors influencing BP or PF were identified using separate multiple linear regression models. RESULTS: The index joint (that is, the most symptomatic joint) was the knee in 118 (94%) and the hip in eight (6%) patients. The median duration of pain and limitation of normal activities were three years and one year, respectively. The mean BP and PF scores of 57.7 and 56.2 points for the patients were substantially lower than the expected scores of 79.3 and 80.8 points for the general Singapore population. Multiple regression analysis showed that less pain was associated with a younger age, shorter duration of symptoms, more years of education, working, and Chinese ethnicity. Better physical function was associated with more years of education, less learned helplessness, less bodily pain, and less severe OA. CONCLUSIONS: Socioeconomic status and psychosocial factors, some of which are potentially modifiable, influence pain or physical function in Asian patients with OA in Singapore.

Aged↗