Abstract: We present a protocol for managing mobile wireless ad hoc networks. The protocol uses h... more Abstract: We present a protocol for managing mobile wireless ad hoc networks. The protocol uses hierarchical clustering of nodes to reduce the number of messages exchanged between the manager and the agents (mobiles). Clustering also enables the network to ...
Acute traumatic spinal cord injury results in disability and use of health care resources, yet da... more Acute traumatic spinal cord injury results in disability and use of health care resources, yet data on contemporary national trends of traumatic spinal cord injury incidence and etiology are limited. To assess trends in acute traumatic spinal cord injury incidence, etiology, mortality, and associated surgical procedures in the United States from 1993 to 2012. Analysis of survey data from the US Nationwide Inpatient Sample databases for 1993-2012, including a total of 63,109 patients with acute traumatic spinal cord injury. Age- and sex-stratified incidence of acute traumatic spinal cord injury; trends in etiology and in-hospital mortality of acute traumatic spinal cord injury. In 1993, the estimated incidence of acute spinal cord injury was 53 cases (95% CI, 52-54 cases) per 1 million persons based on 2659 actual cases. In 2012, the estimated incidence was 54 cases (95% CI, 53-55 cases) per 1 million population based on 3393 cases (average annual percentage change, 0.2%; 95% CI, -0....
Laparoscopic colectomy has significant advantages over open colectomy in the treatment of diverti... more Laparoscopic colectomy has significant advantages over open colectomy in the treatment of diverticular disease with respect to the length of hospital stay, routine hospital discharge, and postoperative morbidity and mortality. Retrospective secondary data analysis. Patients with primary International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes for laparoscopic (709 patients [3.8%]) and open sigmoid resection (17 735 patients [96.2%]) were selected from the 1998, 1999, and 2000 Nationwide Inpatient Samples. These databases represent 20% stratified probability samples of all US community hospital discharges. Sampling weights were used to allow generalization of the study findings to the overall US population. Multiple linear and logistic regression analyses were performed to assess the risk-adjusted association between the surgery type and patient outcomes. Length of hospital stay, in-hospital complications, in-hospital mortality, and the rate of ...
The relationship between hospital volume and outcomes needs to be further elucidated for low-risk... more The relationship between hospital volume and outcomes needs to be further elucidated for low-risk procedures such as surgical therapy of localized breast cancer. The objective of this investigation was to assess the relationship between hospital volume and outcomes for breast cancer surgery. A total of 233,247 patients who underwent breast-conserving therapy (BCT) and breast-ablative therapy (BAT) for localized breast cancer were extracted from 13 years (1988-2000) of the Nationwide Inpatient Samples. Hospital volume was classified as low (<30 cases/year), intermediate (> or =30 to <70 cases/year), and high (> or =70 cases/year). Multiple linear and logistic regression analyses were used to assess the risk-adjusted association between hospital volume and outcomes. In risk-adjusted analyses, patients operated on at low-volume hospitals were 3.04 (p = 0.03) times more likely to die after BCT compared with patients operated on at high-volume hospitals. Similarly, low-volume hospitals had a significantly higher likelihood of postoperative complications (odds ratio [OR] = 1.73, p = 0.01 for BCT; OR = 1.44, p < 0.001 for BAT) compared with high-volume hospitals. Compared with low-volume hospitals, length of hospital stay was significantly shorter and nonroutine patient discharge significantly lower for high-volume providers for both BCT and BAT (all p < 0.001). Patients were also significantly less likely to undergo BCT if operated on in a low- or intermediate-volume hospital compared with a high-volume provider (p < 0.001). High-volume hospitals had significantly lower nonroutine patient discharge, postoperative morbidity and mortality, shorter length of hospital stay, and higher likelihood of performing BCT. Referral of patients with localized breast cancer to high-volume hospitals may be justified.
Age is an established predictor of renal failure among recipients of cadaveric transplants; howev... more Age is an established predictor of renal failure among recipients of cadaveric transplants; however, the impact of donor age on recipient glomerular filtration rate (GFR) among living donor kidney (LDK) transplantations is not well established. We retrospectively analyzed recipient posttransplantation GFR at 12, 36, and 60 months among 315 LDK allograft recipients. The impact of donor age was assessed on the recipient estimated GFR (eGFR) using multivariate linear regression stratified according to donor age <50 years (n = 246) and >or=50 years (n = 69). Whites comprised the majority of both donors and recipients (77%). The majority (58.4%) of donors were female. Mean age (+/- SD) of the donors was 41.0 +/- 10.2 years (range, 20-65 years). The mean age and body mass index (BMI) of the recipients were 43.3 +/- 12.4 years and 26.0 +/- 4.9, respectively. There was no statistically significant difference in the rejection rate between the 2 groups (P = .571). Mean eGFR at 12 months in the younger group was 63.3 +/- 23.7 compared with 54.8 +/- 19.7 in the older group (P = .015). Similarly, a significant difference was observed at the end of 36 months and 60 months of follow-up (61.5 +/- 23.1 vs 49.4 +/- 18.9, and 59.4 +/- 23.0 vs 45.3 +/- 20.8, respectively; both P = .001). Donor age was a statistically significant predictor of eGFR throughout the study period (P < .05). Donor age predicts recipient renal function after living kidney transplantation and needs to be evaluated through a larger prospective investigation.
Rotator cuff tears are the leading cause of shoulder pain and shoulder-related disability and acc... more Rotator cuff tears are the leading cause of shoulder pain and shoulder-related disability and account for 4.5 million physician visits in the United States annually. A careful history and structured physical examination are often sufficient for diagnosing rotator cuff disorders. We are not aware of a clinical review article that presents a structured physical examination protocol of the rotator cuff for the interested clinician. To fill this void, we present a physical examination protocol developed on the basis of review of prior literature and our clinical experience from dedicated shoulder practices. Our protocol includes range of motion testing by using a goniometer, strength testing by using a dynamometer, and select special tests. Among the many tests for rotator cuff disorders that have been described, we chose ones that have been more thoroughly assessed for sensitivity and specificity. This protocol can be used to isolate the specific rotator cuff tendon involved. The protocol can typically be completed in 15 minutes. We also discuss the clinical implications and limitations of the physical examination maneuvers described in our protocol. This protocol is thorough yet time efficient for a busy clinical practice. It is useful in the diagnosis of rotator cuff tears, impingement syndrome, and biceps pathology.
Lead exposure has previously been associated with intellectual impairment in children in a number... more Lead exposure has previously been associated with intellectual impairment in children in a number of international studies. In India, it has been reported that nearly half of the children have elevated blood lead levels (BLLs). However, little is known about risk factors for these elevated BLLs. We conducted a retrospective cross-sectional analysis of data from the Indian National Family Health Survey, a population-based study conducted in 1998-1999. We assessed potential correlates of BLLs in 1,081 children who were < 3 years of age and living in Mumbai or Delhi, India. We examined factors such as age, sex, religion, caste, mother's education, standard of living, breast-feeding, and weight/height percentile. Most children (76%) had BLLs between 5 and 20 microg/dL. Age, standard of living, weight/height percentile, and total number of children ever born to the mother were significantly associated with BLLs (log transformed) in multivariate regression models. Compared with children < or = 3 months of age, children 4-11 and 12-23 month of age had 84 and 146% higher BLLs, respectively (p < 0.001). A low standard of living correlated with a 32.3% increase in BLLs (p = 0.02). Children greater than the 95th percentile for their weight/height had 31% (p = 0.03) higher BLLs compared with those who were below the 5th percentile for their weight/height. Our study found various factors correlated with elevated BLLs in children. The correlation between greater than the 95th percentile weight/height and higher BLL may reflect an impact of lead exposure on body habitus. Our study may help in targeting susceptible populations and identifying correctable factors for elevated BLLs in Mumbai and Delhi.
The objective of our study was to assess the effect of comorbidities (hypertension, diabetes, obe... more The objective of our study was to assess the effect of comorbidities (hypertension, diabetes, obesity, and their combinations) on postoperative complications and discharge status in patients having shoulder, hip, and knee arthroplasty (n = 959,839). The association between outcomes and each of the comorbidities was assessed using multivariable logistic regression after adjusting for age, race, household income, gender, and hospital volume. In the multivariable models, postoperative complications were more likely in patients with hypertension, diabetes, or obesity as compared with patients without these comorbidities (for hypertension, odds ratio = 1.07; 95% confidence interval range, 1.04-1.11; for obesity, odds ratio = 1.3; 95% confidence interval range, 1.22-1.41). The likelihood of a nonhomebound disposition of patients on discharge was 1.30 times (95% confidence interval range, 1.27-1.32) in patients with diabetes and 1.45 times (95% confidence interval range, 1.40-1.49) in patients who were obese as compared with patients without these respective comorbidities. Patients with a combination of comorbidities also had a higher likelihood of postoperative complications and nonhomebound discharge. Results of our study showed that hypertension, diabetes, and obesity are independent predictors of increased postoperative complications and non-homebound discharge in patients undergoing shoulder, hip, or knee arthroplasty. Prognostic study, Level II-1 (retrospective study). See the Guidelines for Authors for a complete description of levels of evidence.
It has been estimated that one in every five cancer deaths worldwide are related to tobacco use. ... more It has been estimated that one in every five cancer deaths worldwide are related to tobacco use. According to the IARC, 10 polycyclic aromatic hydrocarbons (PAH) and 8 tobacco-specific nitrosamines (TSNA), as well as at least 45 other compounds or substances found in tobacco smoke, are potential human carcinogens. The levels of these carcinogens in contents of tobacco and smoke emissions vary between different tobacco products. We evaluated mainstream smoke emissions from cigarettes made with different types of tobacco to examine the relation between their deliveries of TSNAs and PAHs and any possible influence from tobacco nitrate content. To investigate the contribution of tobacco content to mainstream cigarette smoke deliveries without confounders such as filter design, filter ventilation, and paper porosity, we used custom-made, research-grade, unfiltered cigarettes that contained bright, burley, oriental, reconstituted, or mixtures of these tobaccos. Our findings confirm results from other researchers that tobacco type can influence the mainstream smoke delivery of nicotine, TSNAs, and PAHs. However, we found that the effect varies among individual compounds. In addition, we observed a statistically significant relationship between nitrate content and mainstream smoke 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK); nitrate level also influenced the mainstream smoke deliveries of the summed total of the 10 PAHs identified by IARC as potential human carcinogens. The influence of nitrate on mainstream smoke NNK and PAH levels were of different magnitude and direction. Our results tend to indicate an inverse relation exists between NNK and PAH deliveries when considering different tobacco blends.
Abstract: We present a protocol for managing mobile wireless ad hoc networks. The protocol uses h... more Abstract: We present a protocol for managing mobile wireless ad hoc networks. The protocol uses hierarchical clustering of nodes to reduce the number of messages exchanged between the manager and the agents (mobiles). Clustering also enables the network to ...
Acute traumatic spinal cord injury results in disability and use of health care resources, yet da... more Acute traumatic spinal cord injury results in disability and use of health care resources, yet data on contemporary national trends of traumatic spinal cord injury incidence and etiology are limited. To assess trends in acute traumatic spinal cord injury incidence, etiology, mortality, and associated surgical procedures in the United States from 1993 to 2012. Analysis of survey data from the US Nationwide Inpatient Sample databases for 1993-2012, including a total of 63,109 patients with acute traumatic spinal cord injury. Age- and sex-stratified incidence of acute traumatic spinal cord injury; trends in etiology and in-hospital mortality of acute traumatic spinal cord injury. In 1993, the estimated incidence of acute spinal cord injury was 53 cases (95% CI, 52-54 cases) per 1 million persons based on 2659 actual cases. In 2012, the estimated incidence was 54 cases (95% CI, 53-55 cases) per 1 million population based on 3393 cases (average annual percentage change, 0.2%; 95% CI, -0....
Laparoscopic colectomy has significant advantages over open colectomy in the treatment of diverti... more Laparoscopic colectomy has significant advantages over open colectomy in the treatment of diverticular disease with respect to the length of hospital stay, routine hospital discharge, and postoperative morbidity and mortality. Retrospective secondary data analysis. Patients with primary International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes for laparoscopic (709 patients [3.8%]) and open sigmoid resection (17 735 patients [96.2%]) were selected from the 1998, 1999, and 2000 Nationwide Inpatient Samples. These databases represent 20% stratified probability samples of all US community hospital discharges. Sampling weights were used to allow generalization of the study findings to the overall US population. Multiple linear and logistic regression analyses were performed to assess the risk-adjusted association between the surgery type and patient outcomes. Length of hospital stay, in-hospital complications, in-hospital mortality, and the rate of ...
The relationship between hospital volume and outcomes needs to be further elucidated for low-risk... more The relationship between hospital volume and outcomes needs to be further elucidated for low-risk procedures such as surgical therapy of localized breast cancer. The objective of this investigation was to assess the relationship between hospital volume and outcomes for breast cancer surgery. A total of 233,247 patients who underwent breast-conserving therapy (BCT) and breast-ablative therapy (BAT) for localized breast cancer were extracted from 13 years (1988-2000) of the Nationwide Inpatient Samples. Hospital volume was classified as low (<30 cases/year), intermediate (> or =30 to <70 cases/year), and high (> or =70 cases/year). Multiple linear and logistic regression analyses were used to assess the risk-adjusted association between hospital volume and outcomes. In risk-adjusted analyses, patients operated on at low-volume hospitals were 3.04 (p = 0.03) times more likely to die after BCT compared with patients operated on at high-volume hospitals. Similarly, low-volume hospitals had a significantly higher likelihood of postoperative complications (odds ratio [OR] = 1.73, p = 0.01 for BCT; OR = 1.44, p < 0.001 for BAT) compared with high-volume hospitals. Compared with low-volume hospitals, length of hospital stay was significantly shorter and nonroutine patient discharge significantly lower for high-volume providers for both BCT and BAT (all p < 0.001). Patients were also significantly less likely to undergo BCT if operated on in a low- or intermediate-volume hospital compared with a high-volume provider (p < 0.001). High-volume hospitals had significantly lower nonroutine patient discharge, postoperative morbidity and mortality, shorter length of hospital stay, and higher likelihood of performing BCT. Referral of patients with localized breast cancer to high-volume hospitals may be justified.
Age is an established predictor of renal failure among recipients of cadaveric transplants; howev... more Age is an established predictor of renal failure among recipients of cadaveric transplants; however, the impact of donor age on recipient glomerular filtration rate (GFR) among living donor kidney (LDK) transplantations is not well established. We retrospectively analyzed recipient posttransplantation GFR at 12, 36, and 60 months among 315 LDK allograft recipients. The impact of donor age was assessed on the recipient estimated GFR (eGFR) using multivariate linear regression stratified according to donor age <50 years (n = 246) and >or=50 years (n = 69). Whites comprised the majority of both donors and recipients (77%). The majority (58.4%) of donors were female. Mean age (+/- SD) of the donors was 41.0 +/- 10.2 years (range, 20-65 years). The mean age and body mass index (BMI) of the recipients were 43.3 +/- 12.4 years and 26.0 +/- 4.9, respectively. There was no statistically significant difference in the rejection rate between the 2 groups (P = .571). Mean eGFR at 12 months in the younger group was 63.3 +/- 23.7 compared with 54.8 +/- 19.7 in the older group (P = .015). Similarly, a significant difference was observed at the end of 36 months and 60 months of follow-up (61.5 +/- 23.1 vs 49.4 +/- 18.9, and 59.4 +/- 23.0 vs 45.3 +/- 20.8, respectively; both P = .001). Donor age was a statistically significant predictor of eGFR throughout the study period (P < .05). Donor age predicts recipient renal function after living kidney transplantation and needs to be evaluated through a larger prospective investigation.
Rotator cuff tears are the leading cause of shoulder pain and shoulder-related disability and acc... more Rotator cuff tears are the leading cause of shoulder pain and shoulder-related disability and account for 4.5 million physician visits in the United States annually. A careful history and structured physical examination are often sufficient for diagnosing rotator cuff disorders. We are not aware of a clinical review article that presents a structured physical examination protocol of the rotator cuff for the interested clinician. To fill this void, we present a physical examination protocol developed on the basis of review of prior literature and our clinical experience from dedicated shoulder practices. Our protocol includes range of motion testing by using a goniometer, strength testing by using a dynamometer, and select special tests. Among the many tests for rotator cuff disorders that have been described, we chose ones that have been more thoroughly assessed for sensitivity and specificity. This protocol can be used to isolate the specific rotator cuff tendon involved. The protocol can typically be completed in 15 minutes. We also discuss the clinical implications and limitations of the physical examination maneuvers described in our protocol. This protocol is thorough yet time efficient for a busy clinical practice. It is useful in the diagnosis of rotator cuff tears, impingement syndrome, and biceps pathology.
Lead exposure has previously been associated with intellectual impairment in children in a number... more Lead exposure has previously been associated with intellectual impairment in children in a number of international studies. In India, it has been reported that nearly half of the children have elevated blood lead levels (BLLs). However, little is known about risk factors for these elevated BLLs. We conducted a retrospective cross-sectional analysis of data from the Indian National Family Health Survey, a population-based study conducted in 1998-1999. We assessed potential correlates of BLLs in 1,081 children who were < 3 years of age and living in Mumbai or Delhi, India. We examined factors such as age, sex, religion, caste, mother's education, standard of living, breast-feeding, and weight/height percentile. Most children (76%) had BLLs between 5 and 20 microg/dL. Age, standard of living, weight/height percentile, and total number of children ever born to the mother were significantly associated with BLLs (log transformed) in multivariate regression models. Compared with children < or = 3 months of age, children 4-11 and 12-23 month of age had 84 and 146% higher BLLs, respectively (p < 0.001). A low standard of living correlated with a 32.3% increase in BLLs (p = 0.02). Children greater than the 95th percentile for their weight/height had 31% (p = 0.03) higher BLLs compared with those who were below the 5th percentile for their weight/height. Our study found various factors correlated with elevated BLLs in children. The correlation between greater than the 95th percentile weight/height and higher BLL may reflect an impact of lead exposure on body habitus. Our study may help in targeting susceptible populations and identifying correctable factors for elevated BLLs in Mumbai and Delhi.
The objective of our study was to assess the effect of comorbidities (hypertension, diabetes, obe... more The objective of our study was to assess the effect of comorbidities (hypertension, diabetes, obesity, and their combinations) on postoperative complications and discharge status in patients having shoulder, hip, and knee arthroplasty (n = 959,839). The association between outcomes and each of the comorbidities was assessed using multivariable logistic regression after adjusting for age, race, household income, gender, and hospital volume. In the multivariable models, postoperative complications were more likely in patients with hypertension, diabetes, or obesity as compared with patients without these comorbidities (for hypertension, odds ratio = 1.07; 95% confidence interval range, 1.04-1.11; for obesity, odds ratio = 1.3; 95% confidence interval range, 1.22-1.41). The likelihood of a nonhomebound disposition of patients on discharge was 1.30 times (95% confidence interval range, 1.27-1.32) in patients with diabetes and 1.45 times (95% confidence interval range, 1.40-1.49) in patients who were obese as compared with patients without these respective comorbidities. Patients with a combination of comorbidities also had a higher likelihood of postoperative complications and nonhomebound discharge. Results of our study showed that hypertension, diabetes, and obesity are independent predictors of increased postoperative complications and non-homebound discharge in patients undergoing shoulder, hip, or knee arthroplasty. Prognostic study, Level II-1 (retrospective study). See the Guidelines for Authors for a complete description of levels of evidence.
It has been estimated that one in every five cancer deaths worldwide are related to tobacco use. ... more It has been estimated that one in every five cancer deaths worldwide are related to tobacco use. According to the IARC, 10 polycyclic aromatic hydrocarbons (PAH) and 8 tobacco-specific nitrosamines (TSNA), as well as at least 45 other compounds or substances found in tobacco smoke, are potential human carcinogens. The levels of these carcinogens in contents of tobacco and smoke emissions vary between different tobacco products. We evaluated mainstream smoke emissions from cigarettes made with different types of tobacco to examine the relation between their deliveries of TSNAs and PAHs and any possible influence from tobacco nitrate content. To investigate the contribution of tobacco content to mainstream cigarette smoke deliveries without confounders such as filter design, filter ventilation, and paper porosity, we used custom-made, research-grade, unfiltered cigarettes that contained bright, burley, oriental, reconstituted, or mixtures of these tobaccos. Our findings confirm results from other researchers that tobacco type can influence the mainstream smoke delivery of nicotine, TSNAs, and PAHs. However, we found that the effect varies among individual compounds. In addition, we observed a statistically significant relationship between nitrate content and mainstream smoke 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK); nitrate level also influenced the mainstream smoke deliveries of the summed total of the 10 PAHs identified by IARC as potential human carcinogens. The influence of nitrate on mainstream smoke NNK and PAH levels were of different magnitude and direction. Our results tend to indicate an inverse relation exists between NNK and PAH deliveries when considering different tobacco blends.
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