Physical activity during daily life and mortality in patients with peripheral arterial disease

BACKGROUND

We determined whether patients with lower-extremity peripheral arterial disease (PAD) who are more physically active during daily life have lower mortality rates than PAD patients who are less active.

METHODS AND RESULTS

Participants were 460 men and women with PAD (mean age 71.9+/-8.4 years) followed up for 57 months (interquartile range 36.6 to 61.9 months). At baseline, participants were interviewed about their physical activity. Vertical accelerometers measured physical activity continuously over 7 days in 225 participants. Analyses were adjusted for age, sex, race, body mass index, hypertension, smoking, comorbidities, total cholesterol, HDL cholesterol, leg symptoms, and ankle-brachial index. At 57-month follow-up, 134 participants (29%) had died, including 75 participants (33%) who wore accelerometers. Higher baseline physical activity levels measured by vertical accelerometer were associated with lower all-cause mortality (P(trend)=0.003). Relative to PAD participants in the highest quartile of accelerometer-measured physical activity, those in the lowest quartile had higher total mortality (hazard ratio 3.48, 95% confidence interval 1.23 to 9.87, P=0.019). Similar results were observed for the combined outcome of cardiovascular events or cardiovascular mortality (P(trend)=0.005). Higher numbers of stair flights climbed during 1 week were associated with lower total mortality (P(trend)=0.035).

CONCLUSIONS

PAD patients with higher physical activity during daily life have reduced mortality and cardiovascular events compared with PAD patients with the lowest physical activity, independent of confounders. Further study is needed to determine whether interventions that increase physical activity during daily life are associated with improved survival in patients with PAD.

Typhoid carriers among patients with gallstones are at increased risk for carcinoma of the gallbladder

OBJECTIVE

The aim of this study was to identify risk factors for carcinoma of the gallbladder (CaGB) among patients with gallstones (GS) with special reference to role of chronic Salmonella typhi carrier state.

METHODS

A prospective case-control study was conducted in a tertiary care center in India. Cases were defined as consecutive patients with CaGB and GS, whereas controls were patients with GS alone. All were assessed clinically and their demographic data, diet, and smoking history recorded. Patients were detected to be typhoid carriers on the basis of Vi serology by enzyme linked immunosorbent assay. Cases (n = 37) and controls (n = 80) were compared by univariate and logistic regression analysis.

RESULTS

The mean age of the cases and the controls were 53.4 +/- 11 yr and 43.5 +/- 14 yr, respectively. Among the cases, six (16%) patients were detected to be typhoid carriers, in contrast to two (2.5%) among controls (p = 0.01). Compared to controls, cases were more often older (p = 0.0002), of a lower socioeconomic status (p = 0.0005), and smokers (p = 0.0002). Stepwise logistic regression analysis identified typhoid carrier state (OR = 14; CI 2-92), age > or =47 yr (OR = 5; CI 2-14) and smoking (OR = 11; CI 2-71) as the three independent risk factors for development of CaGB among patients with GS.

CONCLUSION

Chronic typhoid carrier state was the most important risk factor among patients with CaGB and gallstones.

Physical activity during daily life and functional decline in peripheral arterial disease

BACKGROUND

Few modifiable behaviors have been identified that are associated with slower rates of functional decline in persons with lower-extremity peripheral arterial disease. We determined whether higher levels of physical activity during daily life are associated with less functional decline in persons with peripheral arterial disease.

METHODS AND RESULTS

The study population included 203 peripheral arterial disease participants who underwent vertical accelerometer-measured physical activity continuously over 7 days and were followed up annually for up to 4 years (mean, 33.6 months). Outcomes were average annual changes in 6-minute walk performance, usual-paced and fast-paced 4-m walking velocity, and the short performance physical battery. Analyses were adjusted for age, sex, race, comorbidities, body mass index, ankle brachial index, smoking, and walking exercise frequency. Higher baseline physical activity levels measured by a vertical accelerometer were associated with significantly less average annual decline in 6-minute walk performance (P for trend=0.010), fast-paced 4-m walking velocity (P for trend=0.002), and the short performance physical battery (P for trend=0.001). Compared with the lowest baseline quartile, those in the highest baseline quartile of physical activity had less annual decline in 6-minute walk performance (-50.82 versus -107.0 ft/y; P=0.019), fast-paced 4-m walking speed (-0.0034 versus -0.111 m . s(-1) . y(-1); P=0.002), and the short performance physical battery (-0.074 versus -0.829; P=0.005).

CONCLUSIONS

Higher physical activity levels during daily life are associated with less functional decline among people with peripheral arterial disease. These findings may be particularly important for the large number of peripheral arterial disease persons without access to supervised walking exercise programs.

Labeling monoclonal antibodies and F(ab')2 fragments with the alpha-particle-emitting nuclide astatine-211: preservation of immunoreactivity and in vivo localizing capacity

alpha-Particles such as those emitted by 211At may be advantageous for radioimmunotherapy since they are radiation of high linear energy transfer, depositing high energy over a short distance. Here we describe a strategy for labeling monoclonal antibodies and F(ab')2 fragments with 211At by means of the bifunctional reagent N-succinimidyl 3-(trimethylstannyl)benzoate. An intact antibody, 81C6, and the F(ab')2 fragment of Me1-14 (both reactive with human gliomas) were labeled with 211At in high yield and with a specific activity of up to 4 mCi/mg in a time frame compatible with the 7.2-hr half-life of 211At. Quantitative in vivo binding assays demonstrated that radioastatination was accomplished with maintenance of high specific binding and affinity. Comparison of the biodistribution of 211At-labeled Me1-14 F(ab')2 to that of a nonspecific antibody fragment labeled with 211At and 131I in athymic mice bearing D-54 MG human glioma xenografts demonstrated selective and specific targeting of 211At-labeled antibody in this human tumor model.

Auditory P300 event-related potentials and number connection test for evaluation of subclinical hepatic encephalopathy in patients with cirrhosis of the liver: a follow-up study

BACKGROUND AND AIMS

The P300 event-related potentials (P3ERP) have been recently advocated for detection of cognitive disturbances in early encephalopathy. However, no systematic follow-up study has been conducted to understand the clinical significance of subclinical hepatic encephalopathy (SHE) detected by this or other methods. The present study was therefore undertaken to examine the diagnostic usefulness of auditory P3ERP in the detection of SHE, to compare it with that of the number connection test (NCT), and to investigate the clinical outcome of patients with SHE in terms of progression to overt encephalopathy.

METHODS

P300 event-related potential latencies were measured and the NCT time was recorded in 81 non-encephalopathic cirrhotic patients (Aged 43.8 +/- 11 years, 23 alcoholic and 58 non-alcoholics) attending the outpatient department at our tertiary care hospital (All India Institute of Medical Sciences Hospital). Cut-off values for abnormality in the tests were developed from age-, sex- and education-matched controls. Patients were followed up at regular intervals for the development of overt encephalopathy, and the identifiable precipitating factors were noted. The P3ERP latencies (363 +/- 34 msec vs 349 +/- 23 msec), as well as NCT time (54.6 +/- 30.6 s vs 39.5 +/- 15.8 s) were significantly prolonged (P< 0.01) in patients with liver cirrhosis when compared with the non-cirrhotic controls.

RESULTS

The P3ERP defects were seen in 24.6% of cirrhotic patients, while NCT time was prolonged in 19.7% of the patients. Nearly 43% of the patients with SHE progressed to overt encephalopathy within a mean duration of 5 months, while only 3.9% of the non-SHE patients did so. Of the patients who developed overt encephalopathy, 64.2% had P3ERP latency prolongations while 35.7% had abnormal NCT.

CONCLUSIONS

The results of the present study suggest that P3ERP and NCT are valid tools for the screening of SHE in cirrhotic patients as there is a greater likelihood of overt encephalopathy development in patients with an abnormality detected by these tests than in patients with no such abnormality.

Fluorine-18 labeling of monoclonal antibodies and fragments with preservation of immunoreactivity

A new method is reported for labeling proteins with the positron-emitting nuclide 18F. Initially, 4-[18F]-fluorobenzylamine was prepared in two steps from aqueous [18F]fluoride in high yield. The 18F acylation agent was formed by reaction of this product with disuccinimidyl suberate. Overall yields for the 4-[18F]fluorobenzylamine succinimidyl ester ([18F]SFBS), decay corrected to the end of cyclotron bombardment, were about 30% in a synthesis time of 60 min. After a 15-min reaction, 30-45% (decay corrected) of the [18F]SFBS could be coupled to intact antibodies and their F(ab')2 and Fab fragments. Coupling yields were dependent on protein concentration but not reaction time. HPLC purification of [18F]SFBS was necessary to obtain optimal coupling efficiency and immunoreactivity. The immunoreactivities of 18F-labeled F(ab')2 and Fab fragments of an antimyosin antibody were 89 +/- 5% and 75 +/- 9%, respectively. Biodistribution studies in normal mice demonstrated similar in vivo behavior of 18F-labeled antibody fragments and those labeled with 125I by using N-succinimidyl 3-[125I]iodobenzoate. These results indicate that this method may be useful for labeling monoclonal antibodies and other proteins and peptides with 18F.

Negative Affect and Risk of Atrial Fibrillation: MESA

Background

Current literature examining the prospective relationship between depression and other measures of negative affect with atrial fibrillation (AF) are limited. We determined the relationships of depression, anger, anxiety, and chronic stress with incident AF in a multiethnic cohort of middle‐ and older‐aged adults.

Methods and Results

This analysis included 6644 MESA (Multi‐Ethnic Study of Atherosclerosis) study participants who were free of AF at baseline. Depressive symptoms were assessed at baseline and defined as either a 20‐item Center for Epidemiologic Studies Depression Scale score ≥16 or use of antidepressant medications. The Spielberger Trait Anger Scale, Spielberger Trait Anxiety Scale, and Chronic Burden Scale were also administered at baseline to assess anger, anxiety, and chronic stress, respectively. The primary outcome was incident AF, identified by follow‐up study visit ECGs, hospital discharge diagnoses, or Medicare claims data. A total of 875 (13%) incident AF cases were detected over a median follow‐up of nearly 13 years. A Center for Epidemiologic Studies Depression Scale score ≥16 (referent, Center for Epidemiologic Studies Depression Scale score <2) and antidepressant use were associated with a 34% and 36% higher risk of AF, respectively, in separate adjusted Cox proportional hazards analyses (hazard ratio, 1.34; 95% CI 1.04–1.74 for Center for Epidemiologic Studies Depression Scale ≥16; hazard ratio, 1.36; 95% CI, 1.04–1.77 for antidepressant use). No significant associations were observed for anger, anxiety, or chronic stress with development of AF.

Conclusions

Depressive symptoms are associated with an increased risk of incident AF. Further study into whether improving depressive symptoms reduces AF incidence is important.

N-succinimidyl 5-(trialkylstannyl)-3-pyridinecarboxylates: a new class of reagents for protein radioiodination

N-Succinimidyl 5-(trialkylstannyl)-3-pyridinecarboxylates (alkyl = Me, Bu) have been prepared and used as a precursor to label N-succinimidyl 5-[131I]iodo-3-pyridinecarboxylate (SIPC). SIPC was obtained in greater than 80% yield from either the methyl or butyl precursor with N-chlorosuccinimide and heating at 60-65 degrees C. Significantly lower yields were observed with tert-butyl hydroperoxide. After a 30-min incubation with [131I]SIPC at pH 8.5, goat IgG, an intact monoclonal antibody (MAb), and a MAb F(ab')2 fragment were labeled in 60-65% yield. Specific binding of the MAb and MAb fragment after SIPC labeling was identical with that observed with N-succinimidyl 3-iodobenzoate and higher than that reported previously for these MAbs after labeling by using the Iodogen method. When 5-[131I]iodonicotinic acid was injected into normal mice, thyroid uptake was less than 0.2% of the injected dose, reflecting the inertness of this compound to deiodination. Paired-label biodistribution studies indicate that for both the MAb and the F(ab')2 labeled by using SIPC, accumulation of activity in the thyroid and other tissues is comparable to that observed when these proteins were labeled by using N-succinimidyl 3-iodobenzoate. The results of this study suggest that SIPC may be a reagent for labeling MAbs with halogen nuclides.

Antituberculosis treatment-induced hepatotoxicity: role of predictive factors

Antituberculosis drug-induced hepatotoxicity is quite common. However, factors predicting its development are still controversial. The objective of the present study was to evaluate the role of certain factors (age and sex of the patient, alcoholism, chronic liver disease, hepatitis B virus carrier status, acetylator status, nutritional status and antituberculosis treatment (ATT) regimen) in predicting the development of ATT-induced hepatitis. In a case-control study, 60 consecutive patients with evidence of ATT-induced hepatitis were studied to assess the possible association of the above-mentioned factors with ATT-induced hepatitis. Body mass index was found to be significantly lower in ATT-induced hepatitis patients (17.2 +/- 2.7) than in controls (19.5 +/- 3.3) (p < 0.05). Pyrazinamide was used in addition to isoniazid and rifampicin in a significantly higher percentage of patients in the ATT-induced hepatitis group (70%) as compared with those in the control group (42%). No significant differences were observed between the two groups with regard to the rest of the parameters.

American Heart Association's Life Simple 7 and Risk of Atrial Fibrillation in a Population Without Known Cardiovascular Disease: The ARIC (Atherosclerosis Risk in Communities) Study

Background

The American Heart Association has defined metrics of ideal cardiovascular health known as Life's Simple 7 (LS7) to prevent cardiovascular disease. We examined the association between LS7 and incident atrial fibrillation (AF) in a biracial cohort of middle‐ and older‐aged adults without known cardiovascular disease.

Methods and Results

This analysis included 13 182 ARIC (Atherosclerosis Risk in Communities) study participants (mean baseline age=54±5.7 years; 56% women; 25% black) free of AF and cardiovascular disease. An overall LS7 score was calculated as the sum of the LS7 component scores and classified as inadequate (0‐4), average (5‐9), or optimal (10‐14) cardiovascular health. The primary outcome was incident AF, identified primarily by ECG and hospital discharge coding of AF through December 31, 2014. A total of 2266 (17%) incident AF cases were detected over a median follow‐up of 25.1 years. Compared with the inadequate category (n=1057), participants in the average (n=8629) and optimal (n=3496) categories each had a lower risk of developing AF in a multivariable Cox proportional hazards model (hazard ratio 0.59, 95% confidence interval 0.51, 0.67 for average; and hazard ratio 0.38, 95% confidence interval 0.32, 0.44 for optimal). In a similar model, a 1‐point‐higher LS7 score was associated with a 12% lower risk of incident AF (hazard ratio 0.88, 95% confidence interval 0.86, 0.89).

Conclusions

A higher LS7 score is strongly associated with a lower risk of AF in individuals without baseline cardiovascular disease. Determining whether interventions that improve the population's cardiovascular health also reduce AF incidence is needed.

Metabolic syndrome and risk of incident peripheral artery disease: the cardiovascular health study

Prior studies evaluating metabolic syndrome (MetS) and incident peripheral artery disease (PAD) have been limited by use of modified MetS criteria and restriction to clinical PAD end points. We investigated MetS and risk of developing a low ankle-brachial index (ABI) and clinical PAD in the Cardiovascular Health Study, a population-based cohort of adults aged ≥65 years. Participants with MetS met at least 3 of 5 Adult Treatment Panel III criteria. Baseline C-reactive protein-MetS or fibrinogen-MetS were defined as presence of 3 of 6 components, with elevated C-reactive protein (>3 mg/L) or fibrinogen (>341 mg/dL) as a sixth component. Incident low ABI, defined as ABI <0.9 and decline of ≥0.15, was assessed among a subset of 1899 individuals with 2 ABI measurements 6 years apart. Over a median follow-up of 13.7 years, 4632 individuals were followed up for clinical PAD, defined as revascularization or diagnosed claudication. Adult Treatment Panel III MetS was associated with both incident low ABI (risk ratio, 1.26; 95% confidence interval [CI], 1.00-1.58) and clinical PAD (hazard ratio, 1.47; 95% CI, 1.11-1.94). Incorporating C-reactive protein or fibrinogen into Adult Treatment Panel III criteria identified an additional 16% to 20% of individuals as having MetS, and both C-reactive protein-MetS and fibrinogen-MetS were associated with incident low ABI (risk ratio, 1.36; 95% CI, 1.07-1.72 and risk ratio, 1.43; 95% CI, 1.13-1.81, respectively) and clinical PAD (hazard ratio, 1.56; 95% CI, 1.17-2.08 and hazard ratio, 1.55; 95% CI, 1.17-2.07, respectively). Among Adult Treatment Panel III MetS criteria, risk of PAD was most strongly associated with hypertension.

Patients with gallstones develop gallbladder cancer at an earlier age

Significant proportions of Indian patients with gallbladder cancer are young. Multiple risk factors for gallbladder cancer are recognized among Indian patients. The effect of these risk factors on the age of development of gallbladder cancer is not known. We conducted a study to determine the influence of risk factors on the age at diagnosis of patients with gallbladder cancer and to assess the interactions between these risk factors. Patients with gallbladder cancer from two tertiary care institutions during the period 1994-2001 were prospectively studied. An ultrasound examination was done to look for the presence of gallstones. The influence of gender, gallstones, socio-economic status, smoking, residence in rural areas and in the Gangetic belt on the age at presentation was analysed using univariate analysis, logistic and linear regression analyses. The mean age of the 121 patients studied was 55+/-11.7 (SD) years. There were 51 (42%) patients aged less than 50 years. The younger patients (age < or =50 years) were more likely to have gallstones (88 versus 66%; P=0.008) and to have come from a lower socio-economic background (88 versus 71%; P=0.02) in comparison with older patients. However, there was no effect of the other risk factors. The independent determinants for younger age of patients with gallbladder cancer on logistic regression analysis were gallstones [odds ratio (OR) 4, 95% confidence interval (CI) 1.5-11; P=0.006] and lower socio-economic status (OR 3.1, 95% CI 1.1-8.6; P=0.03). On linear regression analysis, age at presentation was lowered by 5.6 years if there were associated gallstones. The mean age of patients with these two risk factors was significantly lower than that of those with one risk factor or no risk factor (52+/-12 years versus 57+/-11 years versus 61+/-9 years; P=0.007). In conclusion, the presence of gallstones and lower socio-economic status were both independently associated with a younger age at diagnosis of gallbladder cancer and their effect was additive.

Incidence, spectrum and antibiotic sensitivity pattern of bacterial infections among patients with acute pancreatitis

BACKGROUND AND AIM

Secondary infection of pancreatic necrotic tissue and peripancreatic fluid is a serious complication of acute pancreatitis resulting in significant morbidity and mortality. The aim of this study was to find out the spectrum of bacterial infections, and their antibiotic sensitivity pattern in patients with acute pancreatitis.

METHODS

All consecutive patients with acute pancreatitis were studied prospectively. Detailed investigations were carried out to identify bacterial infections and their antibiotic sensitivities in patients with suspected infection. These investigations included cultures of various body fluids, throat swabs, indwelling cannula and catheter tips. Pancreatic tissue was obtained by using needle aspiration or at surgery for Gram's stain, culture and sensitivity. All cultures were repeated until the presence of infection was confirmed or excluded.

RESULTS

A total of 169 patients with acute pancreatitis were studied during the period between January 1997 and June 2000 (mean age 41.3 years; 116 males and 53 females). Of the 169 patients, 63 had infections at various sites. A total of 80 cultures were positive, and 12 different bacterial isolates were cultured from samples taken from these 63 patients. Polymicrobial infection was seen in 32% of patients. Twenty-four patients had a confirmed pancreatic infection. Blood cultures had a growth of organisms in 19 patients, with evidence of ongoing or worsening pancreatitis, thus raising a strong suspicion of infected necrosis in them. The commonest organisms were Escherichia coli from 20 cultures and Pseudomonas aeruginosa from 18 cultures. The antibiotic sensitivity pattern showed that most bacteria were sensitive to third generation cephalosporins and quinolones; notably among them were cefotaxime, ceftazidime, and ciprofloxacin.

CONCLUSION

Bacterial infections were seen in 37% of patients with acute pancreatitis. The commonest organisms were Pseudomonas aeruginosa and Escherichia coli. Most bacterial isolates were sensitive to third generation cephalosporins and quinolones.

Synthesis of radioiodinated N-succinimidyl iodobenzoate: optimization for use in antibody labelling

N-succinimidyl-3-(tri-n-butylstannyl)benzoate (m-BuATE), N-succinimidyl-3-(tri-methylstannyl)benzoate (m-MeATE) and N-succinimidyl-4-(tri-n-butylstannyl)benzoate (p-BuATE) were synthesized and radioiodinated using either N-chlorosuccinimide (NCS) or t-butylhydroperoxide (TBHP) as the oxidant. Radiohalogenation of m-MeATE proceeded more rapidly than m-BuATE. NCS was the more efficient oxidant at reaction times less than 15 min; use of both TBHP and NCS resulted in nearly quantitative yields after 15 min when m-MeATE was used. Using NCS, achieving optimal antibody coupling and specific binding required purification of the active ester by HPLC; in contrast, with TBHP, only Sep-Pak purification was needed.

Enhanced binding and inertness to dehalogenation of alpha-melanotropic peptides labeled using N-succinimidyl 3-iodobenzoate

Two peptides of potential utility for targeting melanoma cells, alpha-melanocyte-stimulating hormone (alpha-MSH) and its more potent analogue [Nle4,D-Phe7]-alpha-MSH, were radioiodinated in 45-65% yield using N-succinimidyl 3-[125I]iodobenzoate (SIB). To determine whether this labeling method resulted in improved in vitro and in vivo characteristics, these peptides also were labeled with 131I by direct iodination with the iodogen method. For alpha-MSH, the rapid tissue clearance of both radionuclides in mice was consistent with rapid degradation of the peptide; however, significantly lower levels of 125I were observed in thyroid and stomach, reflecting a greater inertness to deiodination. More extensive comparisons were performed with [Nle4,D-Phe7]-alpha-MSH. The in vitro binding of [Nle4,D-Phe7,Lys11-(125I)IBA]-alpha-MSH (prepared using SIB) to the murine B-16 melanoma cell line, 34.1 +/- 4.7%, was more than twice as high as that for [Tyr2(131I),Nle4,D-Phe7]-alpha-MSH (15.0 +/- 0.1%), and its KD was more than 10-fold lower than that for conventionally labeled peptide (10 +/- 5 versus 140 +/- 14 pM). The normal tissue clearance of [Nle4,D-Phe7,Lys11-(125I)IBA]-alpha-MSH in mice was faster than that of [Tyr2(131I),-Nle4,D-Phe7]-alpha-MSH. The 19-40-fold lower activity concentrations of [Nle4,D-Phe7,Lys11-(125I)IBA]-alpha-MSH in tissues accumulating free iodide (thyroid and stomach) suggest a greater inertness of this peptide to deiodination. The primary urinary catabolite of [Nle4,D-Phe7, Lys11-(125I)IBA]-alpha-MSH was the lysine conjugate of iodobenzoic acid, whereas radioiodide was the chief catabolite generated from [Tyr2(131I),Nle4,D-Phe7]-alpha-MSH. We conclude that further evaluation of [Nle4,D-Phe7,Lys11-(125I)IBA]-alpha-MSH for targeting alpha-MSH receptors is warranted and that SIB may be a useful method for the radioiodination of peptides.

Usefulness of the American Heart Association's Life Simple 7 to Predict the Risk of Atrial Fibrillation (from the REasons for Geographic And Racial Differences in Stroke [REGARDS] Study)

The American Heart Association has identified metrics of ideal cardiovascular (CV) health known as Life's Simple 7 (LS7). We determined the prospective relationship between the LS7 and the incident atrial fibrillation (AF) in a biracial cohort. The REasons for Geographic And Racial Differences in Stroke (REGARDS) study enrolled non-Hispanic black and white adults 45 years or older. This analysis included 9,576 REGARDS participants (mean age 63 ± 8.4 years; 57% women; 30% black) who were free of AF at baseline and completed a follow-up examination 9.4 years later. An overall LS7 score was calculated at baseline as the sum of the LS7 component scores and classified as inadequate (0 to 4), average (5 to 9), or optimal (10 to 14) CV health. The primary outcome was incident AF, identified at follow-up by either electrocardiogram or a self-reported medical history of a physician diagnosis. A total of 725 incident AF cases were detected. Compared with the inadequate category (n = 534), participants in the optimal category (n = 1,953) had a 32% lower odds of developing AF (odds ratio 0.68; 95% confidence interval 0.47, 0.99) in a logistic regression model adjusted for demographic characteristics, alcohol use, left ventricular hypertrophy, coronary heart disease, and stroke. A 1-point higher LS7 score was associated with a 5% lower odds of incident AF (odds ratio  = 0.95; 95% confidence interval 0.91, 0.99). In conclusion, better CV health, as defined by the LS7 score, is associated with a reduction in development of AF.

Synthesis and preliminary evaluation of para- and meta-[18F]fluorobenzylguanidine

meta-[18F]Fluorobenzylguanidine ([18F]MFBG) and para-[18F]fluorobenzylguanidine ([18F]PFBG) were synthesized in three steps beginning with a fluoro for nitro exchange reaction on 3- and 4-nitrobenzonitrile, respectively. Overall radiochemical yields were 10-15% for [18F]MFBG and 50-55% for [18F]PFBG in a total synthesis time of 60 min. However, impurities interfered with the binding of the product to target cells. A new route was adopted for the synthesis of [18F]PFBG using 4-nitrilophenyl trimethylammonium trifluoromethanesulfonate (Q.S.) as the starting material. In addition to shortening the overall synthesis time by 10 min, this precursor also eliminated problems associated with the presence of small amounts of starting material in the preparation. In vitro binding of [18F]PFBG prepared by the Q.S. method to SK-N-SH, human neuroblastoma cells was 26.5 +/- 1.1%, compared to 16.9 +/- 1.6% when the nitro precursor was used. Selective uptake of both 18F-labeled isomers in the heart and adrenal was seen in mice. At 4 h, adrenal and heart uptake of [18F]PFBG prepared using Q.S. was 20.3 +/- 4.8 and 5.9 +/- 0.8% ID/g respectively, compared to 23.8 +/- 5.0 and 10.5 +/- 1.7% ID/g for [18F]MFBG. Based on the 5-fold higher radiochemical yields obtained with [18F]PFBG, this isomer would appear to be the more practical choice; however, in vitro and in vivo results suggest that [18F]MFBG exhibits greater similarities to MIBG.

Measuring astatine-211 distributions with SPECT

We have investigated standard SPECT techniques (rotating gamma cameras, multi-hole collimators, and filtered backprojection reconstruction) for imaging astatine-211 distributions. Since 211At emits alpha particles, this nuclide has potential for use in radiotherapy. The capability of imaging this nuclide would allow in vivo evaluation of the distribution and stability of potential 211At-labelled radiotherapeutic agents. 211At decay yields x-rays in the 77-92 keV range in addition to 500-900 keV gamma rays. This study evaluates the feasibility of SPECT imaging using the x-ray emissions of 211At. We have evaluated several collimators, with the determination that the medium-energy collimators we used are suitable, with 7% penetration (uncollimated counts versus collimated counts). Several phantoms were imaged and attenuation coefficients were measured (narrow-beam mu = 0.182 cm-1 for 77-80 keV x-rays in water). Reconstructed images demonstrate qualitative capabilities and a simple quantitative study demonstrates good correction for attenuation and scatter (approximately 10% error), at low count densities, at least for the phantom geometries used in this study.

Behavioral and neurobiological characteristics influencing social hierarchy formation in female cynomolgus monkeys

Socially housed monkeys have been used as a model to study human diseases. The present study examined behavioral, physiological and neurochemical measures as predictors of social rank in 16 experimentally naïve, individually housed female cynomolgus monkeys (Macaca fascicularis). The two behavioral measures examined were novel object reactivity (NOR), as determined by latency to touch an opaque acrylic box placed in the home cage, and locomotor activity assessed in a novel open-field apparatus. Serum cortisol concentrations were evaluated three times per week for four consecutive weeks, and stress reactivity was assessed on one occasion by evaluating the cortisol response to adrenocorticotropic hormone (ACTH) following dexamethasone suppression. Measures of serotonin (5-HT) function included whole blood 5-HT (WBS) concentrations, cerebrospinal fluid (CSF) concentrations of the 5-HT metabolite 5-hydroxyindoleacetic acid (5-HIAA) and brain 5-HT transporter (SERT) availability obtained using positron emission tomography (PET). After baseline measures were obtained, monkeys were assigned to four social groups of four monkeys per group. The two measures that correlated with eventual social rank were CSF 5-HIAA concentrations, which were significantly higher in the animals who eventually became subordinate, and latency to touch the novel object, which was significantly lower in eventual subordinate monkeys. Measures of 5-HT function did not change as a consequence of social rank. These data suggest that levels of central 5-HIAA and measures of novel object reactivity may be trait markers that influence eventual social rank in female macaques.

Hepatotoxicity due to antituberculosis therapy. Clinical profile and reintroduction of therapy

The clinical profile of antituberculosis treatment (ATT)-induced hepatotoxicity is variable, and the reintroduction of ATT in patients who have developed such injury is controversial. We conducted a prospective study to determine the clinical profile in patients with ATT-induced hepatotoxicity and to test a predefined strategy of reintroduction of ATT. Seventy-two consecutive patients with clinical evidence of ATT-induced hepatotoxicity were included. Jaundice was the presenting symptom in 44 (61%) patients; prodromal symptoms were present in 28 (39%). Serious complications developed in 12 (16.6%) patients (fulminant hepatic failure in seven, subacute hepatic failure in four, hepatic encephalopathy in one). Nine patients (three males, six females) died from these complications. The mean duration of treatment before the onset of hepatitis was significantly longer in the group that died (53.22 +/- 36.22 days) than in the rest of the patients (31.07 +/- 30.30 days; p < 0.01). Malnutrition was present in 37 of the 72 patients. After resolution of drug induced hepatitis, reintroduction of isoniazid and rifampicin was possible in 41 of 44 patients. Thus, our results showed that ATT-induced hepatitis carried significant morbidity and mortality, that malnutrition was common in patients with ATT-related hepatitis, and that potentially hepatotoxic antituberculosis agents could be safely reintroduced after recovery from hepatitis.

Lipoprotein (a) and coronary artery calcification: prospective study assessing interactions with other risk factors

BACKGROUND

Elevated plasma lipoprotein (a) [Lp(a)] and coronary artery calcification (CAC) are established cardiovascular risk factors that correlate with each other. We hypothesized that other cardiovascular risk factors could affect their relationship.

METHODS

We tested for interactions of 24 study variables related to dyslipidemia, diabetes, insulin resistance, hypertension, inflammation and coagulation with baseline Lp(a) on change in CAC volume and density over 9.5 years in 5975 Multi-Ethnic Study of Atherosclerosis (MESA) participants, free of apparent cardiovascular disease at baseline.

RESULTS

Elevated Lp(a) was associated with larger absolute increase in CAC volume (3.21 and 4.45 mm3/year higher for Lp(a) ≥30 versus <30 mg/dL, and Lp(a) ≥50 versus <50 mg/dL, respectively), but not relative change in CAC volume. No association was found with change in CAC density when assessing continuous ln-transformed Lp(a). The association between elevated Lp(a) (≥30 mg/dL) and absolute change in CAC volume was greater in participants with higher circulating levels of interleukin-2 soluble receptor α, soluble tumor necrosis factor alpha receptor 1 and fibrinogen (15.33, 11.81 and 7.02 mm3/year in quartile 4, compared to -3.44, -0.59 and 1.91 mm3/year in quartile 1, respectively). No significant interaction was found for other study variables. Similar interactions were seen when assessing Lp(a) levels ≥50 mg/dL.

CONCLUSIONS

Elevated Lp(a) was associated with an absolute increase in CAC volume, especially in participants with higher levels of selected markers of inflammation and coagulation. These results suggest Lp(a) as a potential biomarker for CAC volume progression.

Comparison of endoscopic variceal sclerotherapy with sequential endoscopic band ligation plus low-dose sclerotherapy for secondary prophylaxis of variceal hemorrhage: a prospective randomized study

BACKGROUND

Endoscopic variceal sclerotherapy and band ligation both have certain limitations such as, respectively, esophageal complications and early recurrence of varices.

METHODS

From February 1994 to March 1996, all consecutive patients with portal hypertension due to either cirrhosis or noncirrhotic portal fibrosis and a history of variceal bleeding were included in a prospective study and randomly assigned to receive either endoscopic variceal sclerotherapy alone or endoscopic variceal band ligation plus low-dose endoscopic variceal sclerotherapy.

RESULTS

Of 69 patients, 34 were randomly assigned to receive endoscopic variceal sclerotherapy alone; 35 received endoscopic variceal band ligation plus endoscopic variceal sclerotherapy. Complete variceal eradication rates (85% vs. 80%) and the number of endoscopic sessions required for eradication (6.61 +/- 2.94 vs. 7.85 +/- 3.31) were similar in the endoscopic variceal sclerotherapy and endoscopic variceal band ligation plus endoscopic variceal sclerotherapy groups, respectively. The mean volume of sclerosant required in the combined group (54.94 +/- 33.74 mL) was significantly less than that in the endoscopic variceal sclerotherapy group (81.91 +/- 34.80 mL). The complication and recurrent bleeding rates were significantly higher in the endoscopic variceal sclerotherapy group than those in the combined group (20% and 16% vs. 3% and 3%, respectively).

CONCLUSIONS

Both endoscopic variceal sclerotherapy and endoscopic variceal band ligation plus endoscopic variceal sclerotherapy were comparable in eradicating varices but the combined technique was associated with significantly lower complication and recurrent bleeding rates.

CT enteroclysis in the diagnosis of obscure gastrointestinal bleeding: initial results

AIM

To evaluate the usefulness of computed tomography (CT) enteroclysis in patients with obscure gastrointestinal (GI) bleeding.

MATERIALS AND METHODS

In a prospective study, CT enteroclysis was performed in 21 patients (median age 50 years; range 13-71 years) with obscure GI bleeding in which the source of the bleeding could not be detected despite the patient having undergone both upper GI endoscopic and colonoscopic examinations. The entire abdomen and pelvis was examined in the arterial and venous phases using multisection CT after distending the small intestine with 2l of 0.5% methylcellulose as a neutral enteral contrast medium and the administration of 150ml intravenous contrast medium.

RESULTS

Adequate distension of the small intestine was achieved in 20 of the 21 (95.2%) patients. Potential causes of GI bleeding were identified in 10 of the 21 (47.6%) patients using CT enteroclysis. The cause of the bleeding could be detected nine of 14 (64.3%) patients with overt, obscure GI bleeding. However, for patients with occult, obscure GI bleeding, the cause of the bleeding was identified in only one of the seven (14.3%) patients. The lesions identified by CT enteroclysis included small bowel tumours (n=2), small bowel intussusceptions (n=2), intestinal tuberculosis (n=2), and vascular lesions (n=3). All vascular lesions were seen equally well in both the arterial and venous phases.

CONCLUSIONS

The success rate in detection of the cause of bleeding using CT enteroclysis was 47.6% in patients with obscure GI bleeding. The diagnostic yield was higher in patients with overt, obscure GI bleeding than in those with occult obscure GI bleeding.

Lower extremity nerve function, calf skeletal muscle characteristics, and functional performance in peripheral arterial disease

OBJECTIVES

To determine whether poor lower extremity nerve function is associated with less-favorable calf muscle characteristics and greater functional impairment in people with and without peripheral arterial disease (PAD).

DESIGN

Cross-sectional.

SETTING

Three Chicago-area medical centers.

PARTICIPANTS

Four hundred thirteen participants with PAD (ankle-brachial index (ABI) < 0.90) and 255 without.

MEASUREMENTS

Electrodiagnostic testing of the peroneal nerve was performed. Calf muscle cross-sectional area and percentage fat were measured using computed tomography at 66.7% of the distance between the distal and proximal tibia. Six-minute walk performance was measured.

RESULTS

Adjusting for age, sex, race, ABI, leg symptoms, smoking, physical activity, comorbidities, and other covariates, lower peroneal nerve conduction velocity (NCV) was associated with lower calf muscle area (first quartile 4,770.3 mm(2) , fourth quartile 5,571 mm(2) , P < .001) and poorer 6-minute walk distance (first quartile 989.2 feet, fourth quartile 1,210.8 feet, P < .001) in participants without diabetes mellitus with PAD. Lower peroneal NCV was associated with lower calf muscle area (first quartile 5,166.0 mm(2) , fourth quartile 6,003.8 mm(2) , P = .01) and poorer 6-minute walk distance (first quartile 866.4 feet, fourth quartile 1,082.5 feet, P = .01) in participants with diabetes mellitus and PAD as well. In participants without PAD, lower peroneal NCV was not associated with lower calf muscle area but was associated with poorer 6-minute walk distance only in participants without diabetes mellitus (first quartile 1,317.0 feet, fourth quartile 1,570.4 feet, P-trend < .001).

CONCLUSION

Lower peroneal nerve function is associated with smaller calf muscle area and greater functional impairment in individuals with PAD. Future study is needed to determine whether improving peroneal NCV prevents loss of calf muscle and functional decline in people with PAD.

Association Between Homocysteine and Vascular Calcification Incidence, Prevalence, and Progression in the MESA Cohort

Background While elevated homocysteine has been associated with calcification in several studies, its importance as a cardiovascular risk factor remains unclear. This study examines the relationship between homocysteine and vascular and valve calcification in the MESA (Multi-ethnic Study of Atherosclerosis) cohort. Methods and Results MESA participants with baseline homocysteine measurements and cardiac computed tomography scans were included (N=6789). Baseline and follow-up assessment of vascular (coronary artery [CAC], descending thoracic aorta [DTAC]) and valve (aortic valve [AVC], mitral annular [MAC]) calcification was performed. Prevalence ratio/relative risk regression was used to assess the relationship of homocysteine with prevalent and incident calcification, and multivariable logistic regression was used to assess associations between homocysteine and calcification progression. Elevated homocysteine was associated with greater relative risk of prevalent and incident CAC and incident DTAC. We also identified a strong association between elevated homocysteine and CAC and DTAC progression. Elevated homocysteine was found to confer a >2-fold increased risk of severe CAC progression (defined as ΔCAC ≥100/year) and an ≈1.5-fold increased risk for severe DTAC progression (defined as ΔDTAC ≥100/year). Conclusions To our knowledge, this is the first study demonstrating an association between elevated homocysteine and both incidence and progression of coronary and extra-coronary vascular calcification. Our findings suggest a potential role for elevated homocysteine as a risk factor for severe vascular calcification progression. Future studies are warranted to further assess the utility of homocysteine as a biomarker for vascular calcification incidence and progression. Clinical Trial Registration https://www.clinicaltrials.gov/. Unique identifier: NCT00005487.