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PubMed2005

QSAR for anti-malarial activity of 2-aziridinyl and 2,3-bis(aziridinyl)-1,4-naphthoquinonyl sulfonate and acylate derivatives.

Quantitative structure-activity antimalarial relationships have been studied for 63 analogues of 2-aziridinyl and 2,3-bis(aziridinyl)-1,4-naphthoquinonyl sulfonate and acylate derivatives by means of multiple linear regression (MLR) and artificial neural networks (ANN). The antimalarial activity [-log(IC50x10(6))] of the compounds studied were well correlated with descriptors encoding the chemical structure. Using the pertinent descriptors revealed by a stepwise procedure in the multiple linear regression technique, a correlation coefficient of 0.9394 (s=0.2121) for the training set was obtained for the ANN model in a [3-5-1] configuration. The results show that the antimalarial activity of 2-aziridinyl and 2,3-bis(aziridinyl)-1,4-naphthoquinonyl sulfonate and acylate derivatives is strongly dependent on hydrophobic character, hydrogen-bond acceptors and also steric factors of the substituents.

Acylation↗

PubMed1992

An improved method for adjusting the QT interval for heart rate (the Framingham Heart Study)

Several formulas have been proposed to adjust the QT interval for heart rate, the most commonly used being the QT correction formula (QTc = QT/square root of RR) proposed in 1920 by Bazett. The QTc formula was derived from observations in only 39 young subjects. Recently, the adequacy of Bazett's formula has been questioned. To evaluate the heart rate QT association, the QT interval was measured on the initial baseline electrocardiogram of 5,018 subjects (2,239 men and 2,779 women) from the Framingham Heart Study with a mean age of 44 years (range 28 to 62). Persons with coronary artery disease were excluded. A linear regression model was developed for correcting QT according to RR cycle length. The large sample allowed for subdivision of the population into sex-specific deciles of RR intervals and for comparison of QT, Bazett's QTc and linear corrected QT (QTLC). The mean RR interval was 0.81 second (range 0.5 to 1.47) heart rate 74 beats/min (range 41 to 120), and mean QT was 0.35 second (range 0.24 to 0.49) in men and 0.36 second (range 0.26 to 0.48) in women. The linear regression model yielded a correction formula (for a reference RR interval of 1 second): QTLC = QT + 0.154 (1-RR) that applies for men and women. This equation corrects QT more reliably than the Bazett's formula, which overcorrects the QT interval at fast heart rates and undercorrects it at low heart rates. Lower and upper limits of normal QT values in relation to RR were generated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1996

Risk factors for corneal endothelial injury during phacoemulsification.

PURPOSE: To determine the principal risk factors for corneal endothelial injury during phacoemulsification. SETTING: Hayashi Eye Hospital, Fukuoka, Japan. METHODS: We prospectively investigated 859 consecutive eyes of 800 patients who had had phacoemulsification surgery. The percentage of corneal endothelial cell loss at 3 months after surgery was quantitated using specular microscopy. The firmness of the nucleus was graded by Emery's classification prior to surgery. We selected nine variables that could be associated with endothelial injury. The univariate associations between the endothelial cell loss and these variables were evaluated using simple correlation coefficients. A multiple linear regression analysis was performed to identify independent predictors of endothelial cell loss. RESULTS: In the simple regression analysis, older age, small pupil diameter, high nucleus grade, large nucleus, greater infusion volume, type of IOL implanted, and a greater amount of total emitted ultrasound energy were univariately associated with endothelial cell loss. In the multiple linear regression analysis, the best final model (R2 = 0.42) identified high nucleus grade, greater infusion volume, type of IOL implanted, and large nucleus as independent predictors of endothelial cell loss. CONCLUSION: Both univariate and multivariate analyses identified the firmness of the nucleus as the most significant risk factor for endothelial cell loss. Therefore, mechanical contact with nuclear fragments is considered the principal cause of endothelial injury.

Adult↗

PubMed2005

Inhibition of parathyroid hormone: a dose equivalency study of paricalcitol and doxercalciferol.

INTRODUCTION: Paricalcitol and doxercalciferol are effective in reducing parathyroid hormone PTH concentrations in patients with secondary hyperparathyroidism. The purpose of this study was to determine the relative dose of doxercalciferol (compared to paricalcitol) required to maintain equivalent PTH concentrations in dialysis patients. METHODS: Chronic hemodialysis patients treated with a stable dose of paricalcitol for at least 3 months were randomized to receive doxercalciferol at either 35, 50, or 65% of the paricalcitol dose for 6 weeks. Serum iPTH, calcium, phosphorus, and albumin were determined at baseline and monitored every 2 weeks. A linear regression analysis of percent change in iPTH values by dose group was performed to determine the conversion factor. RESULTS: 27 patients were enrolled. Initial iPTH, adjusted serum calcium, serum phosphorus, and CaxP were similar among the treatment groups. Linear regression analysis demonstrated a conversion factor of 0.57 for the dose of doxercalciferol relative to paricalcitol resulting in equivalent suppression of iPTH. Corrected serum calcium, phosphorus, CaxP product, as well as incidence of hypercalcemia, hyperphosphatemia and CaxP >50 were similar for all groups. CONCLUSION: In patients on a maintenance dose of paricalcitol, dosing doxercalciferol at 55-60% of the paricalcitol dose results in comparable inhibition of PTH.

Adult↗

PubMed1994

Influence of coronary vessel size on renarrowing process and late angiographic outcome after successful balloon angioplasty.

BACKGROUND: Although coronary angioplasty is increasingly applied in the treatment of multivessel disease and a broadening range of vessel size, the influence of vessel size itself on the late results of intervention is unresolved. An influence of vessel size on late outcome would carry implications for the application and evaluation of interventional devices, which are selectively used in larger or smaller vessels. The purpose of the present study was to investigate the influence of vessel size on both the restenosis process and late angiographic outcome in a large homogeneous patient group after successful percutaneous transluminal coronary angioplasty (PTCA). METHODS AND RESULTS: The study population comprised 3072 patients with 3736 successfully dilated native primary coronary artery lesions and satisfactory quantitative angiographic analysis in multiple identical projections before and after PTCA and at a 6-month follow-up. Late luminal loss, minimal luminal diameter (MLD) at follow-up, and net luminal gain, as well as percent diameter stenosis at follow-up, net gain in percent diameter stenosis, restenosis rates (according to three definitions), and net gain index, were all compared among nine equally sized groups (noniles) according to vessel size. A direct influence of vessel size on continuous measures of late result was also evaluated by linear regression. These evaluations provided conflicting information with no consistent influence of vessel size emerging. To elucidate the independent influence of vessel size on the restenosis process (late loss) and late angiographic outcome (MLD at follow-up), multiple linear regression analysis was performed taking into account luminal gain, preprocedural MLD, and lesion location. In this manner, vessel size was found to be exert a significantly positive influence on MLD at follow-up (P < .0001) and an equally negative effect on loss. Correcting for vessel size by using percent stenosis measurements led to an anticipated neutralization of this influence. Lesion location in the left anterior descending coronary artery was found to be independently associated with greater loss and smaller MLD at follow-up (P < .0001). CONCLUSIONS: Increasing coronary vessel size was found to be independently predictive of decreasing late luminal loss and increasing follow-up MLD after successful balloon angioplasty. Apparently superior or inferior late angiographic results of new interventional devices may thus be explained in part by preferential use in larger or smaller vessels, respectively. Devices that can safely optimize the short-term result of intervention may realize their ultimate long-term value in larger coronary vessels.

Aged↗

PubMed2004

[Relationship between fetal lead exposure and birth weight--evaluation using deciduous incisor enamel].

OBJECTIVE: The purpose of this study was to examine the relationship between fetal lead exposure and birth weight, using deciduous incisor enamel as a biomarker and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for analysis of lead. METHODS: We asked dental clinics (n=11) and kindergartens (n=11), mainly in the Tokyo metropolitan area and Miyagi Prefecture, and parents to enroll donors of exfoliate deciduous incisors. Donors who consented to this study voluntarily sent deciduous incisors and questionnaires to the authors between March and October, 2003. The Pb/Ca ratios of inner enamel samples were determined by LA-ICP-MS. The relationship between the lead-to-calcium ratio in the enamel and the birth weight was evaluated by stepwise multiple linear regression analysis. RESULTS: One hundred forty-one subjects (male, 72; female, 69) were enrolled in this study. The mean Pb/Ca ratio in the enamel was as low as 0.24 mg-Pb/kg-Ca (SD=0.17). Stepwise multiple linear regression analysis extracted the following maternal variables with a positive coefficient with birth weight: gestational age (p < 0.01), weight gain during pregnancy (p < 0.01), prepregnancy BMI (body mass index, p < 0.01), and parity (p < 0.05). Lead concentration in the enamel was significantly negatively associated with birth weight (p < 0.05). CONCLUSIONS: Our study indicated that lead concentration in the enamel was inversely related to birth weight. This association was found in a population of which the mean blood lead level was estimated to be as low as about 1 microg/dl. We concluded that in utero low lead exposure decreased birth weight, within the normal range of birth weight.

Birth Weight↗

PubMed2005

Validation of insulin resistance indexes in a stable renal transplant population.

OBJECTIVE: The purpose of this study was to investigate the validity of established insulin resistance indexes, based on fasting blood parameters, in a stable renal transplant population. RESEARCH DESIGN AND METHODS: Fasting insulin, homeostasis model assessment (HOMA), the quantitative insulin sensitivity check index (QUICKI), and McAuley's index were assessed for correlation and agreement with whole-body glucose uptake (M value) divided by prevailing serum insulin concentrations (I value) assessed during a hyperinsulinemic-euglycemic clamp in 51 stable renal transplant recipients, who were at a median of 7.5 years after transplant. Multivariate linear regression analyses were used to determine independent risk factors for insulin resistance. RESULTS: The M/I value correlated with fasting insulin concentration (r = -0.56), HOMA (r = -0.53), QUICKI (r = 0.52), and McAuley's index (r = 0.61) (all P < 0.01). Linear regression showed agreement between all indexes and insulin resistance. However, McAuley's index showed the strongest agreement irrespective of age, sex, renal allograft function, and obesity. In multivariate analysis, fasting insulin concentration (beta = -0.59, P = 0.002), fasting triglyceride concentration (beta = -0.33, P = 0.04), and BMI (beta = -1.22, P = 0.05) were independently associated with the M/I value. CONCLUSIONS: All investigated insulin resistance indexes were valid estimates of insulin resistance in the long-term stable renal transplant population. However, correlation and agreement were strongest for McAuley's index. In addition to fasting insulin and triglyceride concentrations, of which McAuley's index is composed, only BMI seemed to be independently associated with insulin resistance in this population.

Adult↗

PubMed1984

Behavior of hyaluronic acid from gingival epithelium and connective tissue on the analytical ultracentrifuge.

The molecular weights of hyaluronic acid (HA) isolated from separated specimens of human gingival epithelium and connective tissue as well as standard hyaluronic acid preparations have been estimated. The values were determined following substitution of sedimentation values into a previously determined empirical relationship between the reciprocal of the sedimentation coefficient at zero concentration (S-1)0 and molecular weights estimated by sedimentation-diffusion (MsD). The values of (S-1)0 for connective tissue and standard low-molecular weight HA preparations obtained by linear regression of all points indicated molecular weights (MsD) of 340,000 and 205,000 respectively. However, epithelial and standard high-molecular weight HA behaved differently during ultracentrifugation generating a curvilinear relationship between s-1 and concentration. Nevertheless linear extrapolation of a line of best fit of the very lowest concentrations (those which approached zero concentration) provided molecular weight estimates of 860,000 and 2,500,000 respectively. Moreover, similar treatment of s-1 values derived from the previously published data of Laurent, Ryan and Pietruszkiewicz has validated the use of linear regression of s-1 at the lower concentrations alone, to calculate high-molecular weight HA. The curvilinear relationship for s-1 throughout the whole concentration range (0.15-2.3 mg/ml) has been regarded only as a qualitative indication that the HA samples are of relatively high-molecular weight, while a straight line through such data points implies a qualitatively lower molecular weight for HA.

Connective Tissue↗

PubMed2004

Family medicine and hospital specialty match rates: does the economy have anything to do with it?

OBJECTIVE: This study explored whether certain economic markers are associated with changes in the selection of primary care as a career. METHODS: Using linear regression models, we examined whether economic factors in the United States could be used to predict the variability in US senior match rates in family medicine and three hospital-based specialties between 1978 and 2000. RESULTS: A linear regression model using several economic indicators showed that public and private expenditures were associated with the US senior match rates in family medicine, anesthesia, and radiology. As private expenditures increased, the match rate for family medicine fell while the match rates for anesthesia and radiology increased. Increases in public expenditures were associated with increased family medicine match rates and declining match rates for the other two specialties. Increases in private spending resulted in average increases of 0.92% and 2.38% in the anesthesia and radiology match, respectively, with a drop in family medicine match rates of 1.36%. We found that for every 1% increase in public expenditures for health, family medicine match rates rise on average 1.39%, while anesthesia rates fall by 0.84% and radiology rates drop 2.16%. CONCLUSIONS: The amount of public and private funding for health care is associated with US senior match rates in family medicine, anesthesia, and radiology. Changes in these funding sources may predict future student specialty choice and could be used to plan residency match rates in disciplines such as family medicine.

Career Choice↗

PubMed1989

The relationship between microfilarial density and uptake of Foleyella candezi microfilariae by Aedes aegypti.

There was a linear regression in the square root of the numbers of microfilariae abstracted (square root of y) by Aedes aegypti refm strain on the square root of the density of microfilariae in the infecting blood (square root of x). The linear regression is represented by the equation, square root of y = 0.080,59 square root of x + 4.556 (r = 0.627; P less than 0.01). - Ae. aegypti abstracted microfilariae about 1.60 times that expected from the infecting blood meal. This value however decreased, when the microfilariae in the infecting blood meal increased possibly due to error in counting large numbers of microfilariae. - The volumes of blood ingested by three strains of Aedes aegypti (+fm/+fm, refm/refm, reF/reF) appeared to be unaffected by genes controlling susceptibility or refractoriness to filariae (Foleyella candezi). - The Duncan's multiple range test showed similarity (p greater than 0.01) in percentage uptake efficiency, 157.28 and 164.28 for black-eyed homozygous susceptible and red-eyed homozygous susceptible strains respectively. There was significant difference between either of the homozygous susceptible strains and the homozygous refractory triple marker strain (calculated F-value = 28.61; critical tabular F-value = 10.92; p less than 0.01). Therefore, the % uptake efficiency of Ae. aegypti for F. candezi microfilariae is influenced by the gene (fm) which also allows the development of the filariae. - The percentage efficiency (observed/expected X 100) in abstracting microfilariae from infecting blood source by homozygous susceptible strains was about twice that (80.98%) observed for a homozygous refractory triple marker strain.

Aedes↗

PubMed1995

Multicentre evaluation of the Serono SR1 assay for prostate specific antigen.

This report describes the findings of an evaluation of the validity of the new, highly automated Serono SR1 enzyme immunoassay for prostate specific antigen performed at three European sites. Within-run precision was below 5.5% at the clinically important decision point of 4 micrograms/l, less than 10% below 3 micrograms/l and less than 5% above 4 micrograms/l. Between-run precision was below 12% at each site and between-site precision was less than 14%. Dilution series were shown to be parallel to the standard curve on 12 samples with neat prostate specific antigen concentrations ranging from 20 to 88 micrograms/l (linear regression slopes and correlation coefficients of 1.00 to 1.06 and 0.972 to 1.000 respectively). Comparisons with Hybritech Tandem-E and -R and Roche Cobas Core prostate specific antigen methods used routinely at the three sites were good (linear regression slopes 1.04 to 1.13, correlation coefficients 0.96 to 0.99), but results were significantly lower than the Ciba Corning ACS180 (slope 0.66, correlation coefficient 0.99). The assay presents a precise, robust and valid diagnostic tool offering additional advantages of non-isotope automation.

Cross Reactions↗

PubMedDate not supplied

[Effect of the ingestion of food and gynecologic risk factors on breast cancer risk in Valencia].

OBJECTIVES: The present case-control study was undertaken to elucidate the role of recent diet, specially in the influence of food groups, in the development of cancer of the breast. MATERIAL AND METHODS: A case-control study of breast cancer (BC) was conducted between April to November 1997 in Valencia (Spain). Cases were 65 women aged 35-78 years. Controls included 78 women aged 34-82. Dietary habits were investigated through a validated food frequency consumption questionnaire (FFQ) included 100 foods. One summary questions were included, concerning all food items of a certain type or food frequently consumption. The difference between variables was tested by the chi-square method. For each food item, quintiles of consumption were calculated by dividing the frequency distribution of the entire study group into 20th, 40th, 60th and 80th percentiles and multiple linear regression analysis were fitted to the data. To assess the independent associations between selected BC risk factors and BC stage. RESULTS: A significant trend of increasing risk with increasing intake emerged for the following food groups: Cereal dish (rice) (OR = 1.1; 95% CI: 0.1-10.0), poultry (OR = 6.0; 95% CI: 0.9-43.9), beef meat (OR = 1.3: 95% CI: 0.5-3.6) and high intake of some food groups exerted a significant protection against development of BC: eggs (OR = 0.6; 95% CI: 0.2-1.9), olive oil (OR = 0.5; 95% CI: 0.1-2.0), tomatoes (OR = 0.5; 95% CI: 0.1-1.8). When linear regression analyses was performed, consumption of tomatoes and parity showed an inverse association statistically significant with the stage of BC. CONCLUSIONS: Consumption of tomatoes, mainly, consumption of eggs and olive oil, and parity exhibited a statistically significant relationship (p < 0.05) with BC stage in Valencia (Spain).

Adult↗

PubMed1997

Wear of polyethylene acetabular components in total hip arthroplasty. An analysis of one hundred and twenty-eight components retrieved at autopsy or revision operations.

We evaluated the rates of volumetric wear and the patterns of wear of 128 acetabular components retrieved during an autopsy or a revision operation between one and twenty-one years after total hip arthroplasty. Twenty-two all-polyethylene components were retrieved at autopsy from hips that had been functioning well at the time of death (Group A). The remaining 106 components--eighty-four all-polyethylene components (Group B) and twenty-two metal-backed components (Group C)--were retrieved during revision operations. All 128 components had been inserted with cement. The mean rate of volumetric wear, determined directly with a fluid-displacement method, was thirty-five cubic millimeters per year (range, eight to 116 cubic millimeters per year) for Group A, sixty-two cubic millimeters per year (range, eight to 256 cubic millimeters per year) for Group B, and ninety-four cubic millimeters per year (range, twelve to 284 cubic millimeters per year) for Group C. Multivariate regression analysis showed a significant relationship (p < 0.05) between the size of the femoral head and the calculated mean annual rate of volumetric wear. The rate of volumetric wear was highest in association with thirty-two-millimeter femoral heads and lowest in association with twenty-two-millimeter heads; according to linear regression analysis, this represented a 7.5 per cent increase (Group A) or a 10 per cent increase (Group B) in the rate of wear for every one-millimeter increase in the size of the head. Linear regression analysis also showed a significant relationship between the duration that the implant had been in situ and the rate of wear (p < 0.05), with the rate being highest initially after the operation and decreasing with an increasing duration in situ. With the numbers available, the patient's age and gender and the side of the arthroplasty did not have a significant relationship to the annual rate of volumetric wear. Increased thickness of the polyethylene was related to a decreased rate of wear (p < 0.05) in the group of metal-backed components, which had a 25 per cent increase in the rate of wear for every one-millimeter decrease in thickness, but not in the other groups. The estimated median annual rates of wear, after adjustment of confounding variables to a hypothetical constant set of median values for the parameters (duration in situ, 132 months; diameter of the femoral head, twenty-six millimeters; and thickness of the polyethylene, eight millimeters), were significantly different among the three groups of components (p < 0.05). Histological evaluation of the worn surfaces showed the predominant mechanisms of wear to be abrasion and adhesion rather than fatigue-cracking or delamination. The highly worn areas were polished to a glassy finish on gross examination, but scanning electron microscopy showed numerous multidirectional scratches along with fine, drawn-out fibrils with a diameter of one micrometer or less oriented parallel to each other. These fibrils are the most likely source of submicrometer wear particles. Thus, wear appeared to occur mostly at the surface of the components and to be due to large-strain plastic deformation and orientation of the surface layers into fibrils that subsequently ruptured during multidirectional motion.

Acetabulum↗

PubMed2003

A simple method to calculate cyclosporine dosage to obtain a target C2 drug level.

C(2) Cyclosporine (CsA) level, as a surrogate of area under the time-concentration curve (AUC) 0-4 hours, is a good predictor of drug absorption and clinical outcome after kidney transplantation. It has been difficult to define the optimal C(2) level in the individual case and given the broad range of C(2) due to interindividual absorption variability it has been troublesome to determine the drug dose needed to obtain an expected C(2)-CsA concentration. In this study data of 16 stable renal and renal/pancreas recipients treated with prednisone, azathioprine, and CsA (Neoral) managed by C(0) level was examined. CsA concentrations at time 0 (basal), 2, 6, and 12 hours post CsA (Neoral) intake were determined the day of the study. A significant linear regression level was established between C(2) (but not C(0), C(6) and C(12)) and the dosage expressed as mg/kg/d (P = 0.0113, correlation coefficient r = 0.573018). Subsequently, another 27 renal transplant recipients were studied retrospectively and divided into three groups according to posttransplant period: 1 to 6, 7 to 12, and beyond 12 months after transplant. Equations derived from the relationship between C(2) and dose (mg/kg/d) were similar between the three groups and when compared with the first study. A formula obtained from the 27 patients in the whole posttransplant period (mg/kg/d = C(2) x 0.0010208 + 1.86125) was applied to patients of the first study obtaining a regression coefficient between actual and calculated CsA dose of 0.6145 (P = 0.01). A more accurate equation (P = 0.0001, r = 0.5925) was obtained by analyzing 145 C(2) determinations covering a period from 1 month to 8 years following transplant which gave a linear regression line defined by the equation C(2) x 0.001473 + 1.6673. This equation would permit the calculation mg/kg/d of CsA (Neoral) dose to obtain an expected C(2) level. The derived equation shown in this paper has a predictive value of 50% to 60% only, but can help to find adequate dosage in the presence of an inappropriate C(2) level.

Adolescent↗

PubMed1989

[Recent trends and prognosis of pulmonary diseases in Japan].

To determine trends of death rates for patients with chronic pulmonary diseases the author compiled the numbers of deaths per 100,000 Japanese population per annum based on the annual reports of the Japan Vital Statistics for the past 43 years. Death rates for the newborn population as well as for the younger population decreased while those for the aged population remained unchanged. Increasing numbers of deaths from lung cancer and decreasing numbers of death from pulmonary tuberculosis were noted. The death rate from the chronic obstructive lung diseases was maintained while the death rate for diffuse fibrotic lung diseases tended to be elevated. Baseline reference values for respiratory physiology parameters, established by the Special Commission for Respiration Physiology of the Japan Society of Chest Diseases, were presented by single linear regression equations represented in terms of age covering the subject's whole age span, including the aged population. The author carried out further analyses based on the data collected in a multi-center cross-sectional survey and concerning, some parameters found consistent differences the linear regression equation calculated for the aged population from those for the younger population. A longitudinal survey conducted by follow-up observations at Keio University Hospital to determine the annual decline of parameters on respiration physiology was designed to cover healthy subjects as well as subjects with chronic pulmonary diseases. Annual declines in vital capacity, forced vital capacity, forced expiratory volume in one second, arterial oxygen tension and arterial carbon dioxide tension showed linear changes throughout the entire age span. Some parameters, such as flow max at 25% vital capacity or alveolar-arterial oxygen tension difference (AaDO2), demonstrated statistically consistent differences in annual decline between younger and older age populations. The annual decline of parameters in patients with chronic pulmonary diseases demonstrated consistently larger values compared with those for healthy subjects. In a study on the pathophysiology and prognosis of patients with respiratory failure with/or without cor pulmonale extension of the survival period for the patients with cor pulmonale was demonstrated.

Adolescent↗

PubMed2006

Boosting support vector regression in QSAR studies of bioactivities of chemical compounds.

In this paper, boosting has been coupled with SVR to develop a new method, boosting support vector regression (BSVR). BSVR is implemented by firstly constructing a series of SVR models on the various weighted versions of the original training set and then combining the predictions from the constructed SVR models to obtain integrative results by weighted median. The proposed BSVR algorithm has been used to predict toxicities of nitrobenzenes and inhibitory potency of 1-phenyl[2H]-tetrahydro-triazine-3-one analogues as inhibitors of 5-lipoxygenase. As comparisons to this method, the multiple linear regression (MLR) and conventional support vector regression (SVR) have also been investigated. Experimental results have shown that the introduction of boosting drastically enhances the generalization performance of individual SVR model and BSVR is a well-performing technique in QSAR studies superior to multiple linear regression.

Algorithms↗

PubMed2004

Gunshot wounds: bullet caliber is increasing, 1998-2003.

In 1999, Caruso reported data from the level 1 trauma center in Newark, New Jersey, documenting "...an ominous trend toward the use of larger caliber firearms in accidents, homicides and suicides." Those data were derived from measurements of bullets removed from our trauma patients and submitted to the Surgical Pathology laboratory from 1981 through 1997. We further document this trend with measurements of similar source bullets from 1998 through 2002. During the same time, we recorded mortality among gunshot wound victims treated at our trauma center. Bullets submitted to surgical pathology during the years 1998 through 2002 were measured with a millimeter rule to determine caliber or transverse diameter. A total of 367 bullets were studied in this 5-year period. Bullets deformed beyond measurability (approximately 22%) and shotgun pellets (< 5%) were excluded from our study. Bullet calibers were expressed in terms of mean plus or minus standard error (x +/- SE). Mortality figures were derived from analysis of medical records concerning the outcomes all victims of gunshot wounds (E 922, E 965) treated at our hospital during the years studied and expressed as percentages. Linear regression of mean bullet caliber over time was performed, and analysis of variance was used to assess statistical significance of apparent differences in mortality. Bullet caliber continued to increase from 8.47 +/- 0.22 to 9.16 +/- 0.15 mm during the 5-year observation period. Linear regression reveals R = 0.9649, P < 0.01. Mortality ranged from 4.7 per cent to 10.7 per cent but the differences were not significant (P > 0.20). These data support a continued trend toward the use of larger caliber firearms in accidents, homicides, and suicides. Mortality does not change during this time and presumably because of improvements in treatment, from resuscitation to definitive surgery and its convalescence.

Cause of Death↗

PubMed2005

A simple different method to use proximal isovelocity surface area (PISA) for measuring mitral valve area.

BACKGROUND: Angle-correction is an important limiting factor for using proximal isovelocity surface area (PISA) method in measuring mitral valve area (MVA). In this study, we derived a novel formula, which simplifies the angle-correction, and tested its use in patients with mitral stenosis (MS). METHODS: The study included 30 MS patients without concomitant aortic or mitral regurgitation. We used mathematical equations and established a relation between the angle and its corresponding border, 'a', by using linear regression analysis. It was found that MVA is equal to [(1.11*a2 + 0.95)* r2 (Val/Vmax)]. We compared this formula with plain angle-corrected and solid angle-corrected PISA methods, planimetry (reference method) and pressure-half time method by linear regression analysis. RESULTS: All methods were in significant relation with the reference method, two-dimensional planimetry. We found that there is a good relation between our method and planimetry (r = 0.79, p < 0.001), pressure half-time method (r = 0.85, p < 0.001), angle-corrected PISA method (r = 0.99, p < 0.001), and solid angle-corrected PISA method (r = 0.88, p < 0.001). The time duration of the new method was shorter (p < 0.001). CONCLUSION: Our method is an easy way for applying angle-corrected PISA method to mitral valve area measurement in patients with mitral stenosis. Absence of the need for estimating the angle is the major advantage.

Adult↗