Assessment of Interhemispheric Cerebral Perfusion Deficit in Carotid Artery Stenosis

Asymptomatic carotid stenosis patients manifest compromised cognitive performance compared to controls. Cerebral perfusion deficit could be an important contributor to cognitive impairment. The relationship between carotid stenosis and cerebral perfusion deficit is not established. If established, this could lead to a more informed selection of ACS patients likely to benefit from carotid revascularization. Perfusion-weighted MR imaging (PWI) is a clinically viable non-invasive technique to quantify cerebral perfusion. However, its impact is limited due to lack of efficient clinical tools to analyze PWI data in different brain regions for characterizing interhemispheric perfusion asymmetry. Development of automated approaches to characterize clinically relevant perfusion deficits is therefore required. Moreover, there is no established evidence of association between perfusion deficit and stenosis severity. In this paper, we propose an approach to quantify interhemispheric perfusion differences in different brain regions using clinical data. Our proposed metrics, based on the PWI mean transit time, for characterizing difference between ipsilateral and contralateral hemispheres demonstrate a very strong relationship with Doppler ultrasound based peak systolic velocity measured at stenosis. Our approach also highlights dependence of perfusion asymmetry on effective collateralization through the cerebral vasculature. In future studies, we plan to extend this method to a larger cohort and refine the methods for validating novel biomarker for risk-stratification of carotid stenosis.

Structural and Volumetric Brain MRI Findings in Mild Traumatic Brain Injury

BACKGROUND AND PURPOSE

Routine MR imaging findings are frequently normal following mild traumatic brain injury and have a limited role in diagnosis and management. Advanced MR imaging can assist in detecting pathology and prognostication but is not readily available outside research settings. However, 3D isotropic sequences with ∼1-mm³ voxel size are available on community MR imaging scanners. Using such sequences, we compared radiologists' findings and quantified regional brain volumes between a mild traumatic brain injury cohort and non-brain-injured controls to describe structural imaging findings associated with mild traumatic brain injury.

MATERIALS AND METHODS

Seventy-one military personnel with persistent symptoms and 75 controls underwent 3T MR imaging. Three neuroradiologists interpreted the scans using common data elements. FreeSurfer was used to quantify regional gray and white matter volumes.

RESULTS

WM hyperintensities were seen in 81% of the brain-injured group versus 60% of healthy controls. The odds of ≥1 WM hyperintensity in the brain-injured group was about 3.5 times the odds for healthy controls (95% CI, 1.58-7.72; P = .002) after adjustment for age. A frontal lobe-only distribution of WM hyperintensities was more commonly seen in the mild traumatic brain injury cohort. Furthermore, 7 gray matter, 1 white matter, and 2 subcortical gray matter regions demonstrated decreased volumes in the brain-injured group after multiple-comparison correction. The mild traumatic brain injury cohort showed regional parenchymal volume loss.

CONCLUSIONS

White matter findings are nonspecific and therefore a clinical challenge. Our results suggest that prior trauma should be considered in the differential diagnosis of multifocal white matter abnormalities with a clinical history of mild traumatic brain injury, particularly when a frontal predilection is observed.

Comprehensive Evaluation of Healthy Volunteers Using Multi-Modality Brain Injury Assessments: An Exploratory, Observational Study

Introduction: Even though mild traumatic brain injury is common and can result in persistent symptoms, traditional measurement tools can be insensitive in detecting functional deficits after injury. Some newer assessments do not have well-established norms, and little is known about how these measures perform over time or how cross-domain assessments correlate with one another. We conducted an exploratory study to measure the distribution, stability, and correlation of results from assessments used in mild traumatic brain injury in healthy, community-dwelling adults. Materials and Methods: In this prospective cohort study, healthy adult men and women without a history of brain injury underwent a comprehensive brain injury evaluation that included self-report questionnaires and neurological, electroencephalography, sleep, audiology/vestibular, autonomic, visual, neuroimaging, and laboratory testing. Most testing was performed at 3 intervals over 6 months. Results: The study enrolled 83 participants, and 75 were included in the primary analysis. Mean age was 38 years, 58 were male, and 53 were civilians. Participants did not endorse symptoms of post-concussive syndrome, PTSD, or depression. Abnormal neurological examination findings were rare, and 6 had generalized slowing on electroencephalography. Actigraphy and sleep diary showed good sleep maintenance efficiency, but 21 reported poor sleep quality. Heart rate variability was most stable over time in the sleep segment. Dynavision performance was normal, but 41 participants had abnormal ocular torsion. On eye tracking, circular, horizontal ramp, and reading tasks were more likely to be abnormal than other tasks. Most participants had normal hearing, videonystagmography, and rotational chair testing, but computerized dynamic posturography was abnormal in up to 21% of participants. Twenty-two participants had greater than expected white matter changes for age by MRI. Most abnormal findings were dispersed across the population, though a few participants had clusters of abnormalities. Conclusions: Despite our efforts to enroll normal, healthy volunteers, abnormalities on some measures were surprisingly common. Trial Registration: This study was registered at www.clinicaltrials.gov, trial identifier NCT01925963.

Use of Radiology Procedure Codes in Health Care: The Need for Standardization and Structure

Radiology procedure codes are a fundamental part of most radiology workflows, such as ordering, scheduling, billing, and image interpretation. Nonstandardized unstructured procedure codes have typically been used in radiology departments. Such codes may be sufficient for specific purposes, but they offer limited support for interoperability. As radiology workflows and the various forms of clinical data exchange have become more sophisticated, the need for more advanced interoperability with use of standardized structured codes has increased. For example, structured codes facilitate the automated identification of relevant prior imaging studies and the collection of data for radiation dose tracking. The authors review the role of imaging procedure codes in radiology departments and across the health care enterprise. Standards for radiology procedure coding are described, and the mechanisms of structured coding systems are reviewed. In particular, the structure of the RadLex™ Playbook coding system and examples of the use of this system are described. Harmonization of the RadLex Playbook system with the Logical Observation Identifiers Names and Codes standard, which is currently in progress, also is described. The benefits and challenges of adopting standardized codes-especially the difficulties in mapping local codes to standardized codes-are reviewed. Tools and strategies for mitigating these challenges, including the use of billing codes as an intermediate step in mapping, also are reviewed. In addition, the authors describe how to use the RadLex Playbook Web service application programming interface for partial automation of code mapping. ^© RSNA, 2017.

Genetic analysis of first lactation production traits in Kankrej cattle

Aim:

The aim was to estimate genetic factors affecting the first lactation milk production traits in Kankrej cattle of North Gujarat.

Materials and Methods:

The 475 first lactation records of Kankrej cows that were maintained at the Livestock Research Station, Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar, Gujarat, over a period of 35 years from 1980 to 2014 were studied. The least squares maximum likelihood program was used to estimate genetic parameters of first lactation traits. Heritability was estimated through paternal half-sib analysis in adjusted data.

Results:

The heritability estimate for production traits was 0.40±0.17, 0.45±0.17, 0.35±0.18, and 0.20±0.14 for standard 300 days milk yield (F300Y), total lactation milk yield (FLY), wet average (FWA), and lactation length (FLL), respectively, in the first parity. All the genetic and phenotypic correlations among different production efficiency traits were high and positive. Genetic correlations between F300Y and FLY, FLL, and FWA were 0.80±0.20, 0.59±0.16, and 0.81±0.32, where as the phenotypic correlations were 0.969, 0.688, and 0.868, respectively. Genetic correlations of FLY with FLL and FWA were 0.60±0.13 and 0.79±0.20, whereas the phenotypic correlations were 0.777 and 0.817, respectively. Genetic and phenotypic correlation between FLL and FWA was 0.63±0.28 and 0.31, respectively.

Conclusion:

The heritability estimate of all first parity lactation traits waslow to medium (0.20-0.45) indicated the scope for further improvement in this trait through selection as well as managemental practice. Higher genetic and phenotypic correlation between thefirst lactation milk production traits gives theidea that genetic gain due to selection for one trait also givesmorecorrelated response of selection for other traits which is economically advantageous.

A rare case of β-hCG production by a solitary fibrous tumor of the pleura

BACKGROUND

Solitary fibrous tumors are rare tumors of mesenchymal origins, most commonly seen arising from the pleural lining of the lungs. These are generally benign tumors, which in rare cases have been identified to be associated with multiple para-neoplastic syndromes.

CASE REPORT

This is a case of a solitary fibrous tumor of the pleura in a 49 year old female which was found to be associated with elevated levels of serum beta human chorionic gonadotropin β-hCG). Due to the lack of plausible causes for elevated β-hCG in the patient, immune-histochemical staining of the tumor specimen for β-hCG was obtained. This confirmed the patient's solitary fibrous tumor as the source of the β-hCG. The patient was also found to have a possible paraneoplastic syndrome with irregular menstruation and hot flushes from the secreted β-hCG.

CONCLUSIONS

This is the first reported case of solitary fibrous tumors of the pleura producing {b-hCG. Multiple types of lung tumors have been associated with production of β-subunit of human chorionic gonadotropin. Production of β-hCG by these tumors has been associated with a poor prognosis. In this case, we find an aggressive form of solitary fibrous tumor associated with production of β-hCG and associated paraneoplastic syndrome secondary to the β-hCG. Further study is required to identify the frequency of this phenomenon and the implications of β-hCG production in the prognosis of the solitary fibrous tumors.

Ultraviolet spectrophotometry (dual wavelength and chemometric) and high performance liquid chromatography for simultaneous estimation of meropenem and sulbactam sodium in pharmaceutical dosage form

UV spectrophotometric and high performance liquid chromatography (HPLC) methods were developed for simultaneous determination of meropenem (MERM) and sulbactam sodium (SB) in injection. UV spectrophotometric methods were developed using 0.1N sodium hydroxide as solvent. The Beer's plot for dual wavelength method was linear in the range of 4-24 μg mL(-1) and 2-12 μg mL(-1) for MERM and SB, respectively. The percent recoveries were found to be 98.52±1.23% for MERM and 101.45±1.1% for SB. Chemometrics assisted UV spectrophotometry was performed using Partial Least Square (PLS) analysis model and Principal Component Regression (PCR) analysis model. The % recoveries of the MERM were found to be 100.61±0.06% and 101.31±0.12% using PLS and PCR, respectively. The % recoveries of the SB were found to be 98.29±0.09% and 97.61±0.13% using PLS and PCR, respectively. Chromatography was performed on Hypersil BDS C18 column using methanol:acetonitrile:water (10:20:70 v/v/v) as mobile phase. The retention times of MERM and SB were found to be 2.9 min and 2.25 min, respectively. Developed HPLC method was found to be linear in the range of 50-250 μg mL(-1) and 25-125 μg mL(-1) for MERM and SB, respectively. The % recoveries were found to be 98.85±0.25% and 98.63±0.34% for MERM and SB, respectively. The developed analytical methods did not show any interference of the excipients when applied to pharmaceutical dosage form.

Leucas aspera: A review

Leucas aspera commonly known as ‘Thumbai’ is distributed throughout India from the Himalayas down to Ceylon. The plant is used traditionally as an antipyretic and insecticide. Medicinally, it has been proven to possess various pharmacological activities like antifungal, antioxidant, antimicrobial, antinociceptive and cytotoxic activity. Further, studies reveal the presence of various phytochemical constituents mainly triterpenoids, oleanolic acid, ursolic acid and b-sitosterol, nicotine, sterols, glucoside, diterpenes, phenolic compounds (4-(24-hydroxy-1-oxo-5-n-propyltetracosanyl)-phenol). These studies reveal that L. aspera is a source of medicinally active compounds and have various pharmacological effects; hence, this drug encourage finding its new therapeutic uses.

Fatal cross infection by carbapenem-resistant Klebsiella in two liver transplant recipients

Members of the family Enterobacteriaceae including Klebsiella have re-emerged as major pathogens in solid organ transplantation. The recent appearance and dissemination of carbapenemase-producing Enterobacteriaceae in Europe and the northeastern United States represents a major challenge to the treatment of enteric gram-negative bacterial infections in immunocompromised patients; however, few reports have detailed the outcomes of such infections. Here we report 2 cases of Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella infections in orthotopic liver transplant recipients, which were the index case and initial secondary case for an outbreak of KPC-producing Enterobacteriaceae in our institution. In both instances, the pathogens were initially misidentified as being carbapenem sensitive, the infections recurred after cessation of directed therapy, and the patients ultimately succumbed to their infections.

Use of pyrosequencing to identify point mutations in domain V of 23S rRNA genes of linezolid-resistant Staphylococcus aureus and Staphylococcus epidermidis

A pyrosequencing assay was used for the rapid characterization of linezolid-resistant isolates of Staphylococcus aureus and Staphylococcus epidermidis. The assay identified base substitutions in copies of the 23S rRNA gene and determined the percentage of alleles with the mutation. Modifications of the assay were necessary to identify all mutations in the 23S rRNA genes of S. epidermidis that were associated with linezolid resistance. A C2534T mutation was identified in S. epidermidis that was not previously reported in a linezolid-resistant isolate.

Evaluation of methods to identify the Klebsiella pneumoniae carbapenemase in Enterobacteriaceae

The Klebsiella pneumoniae carbapenem (KPC) beta-lactamase occurs in Enterobacteriaceae and can confer resistance to all beta-lactam agents including carbapenems. The enzyme may confer low-level carbapenem resistance, and the failure of susceptibility methods to identify this resistance has been reported. Automated and nonautomated methods for carbapenem susceptibility were evaluated for identification of KPC-mediated resistance. Ertapenem was a more sensitive indicator of KPC resistance than meropenem and imipenem independently of the method used. Carbapenemase production could be confirmed with the modified Hodge test.

Novel retinoic acid metabolism blocking agents have potent inhibitory activities on human breast cancer cells and tumour growth

Antitumour effects of retinoids are attributed to their influence on cell proliferation, differentiation, apoptosis and angiogenesis. In our effort to develop useful agents for breast cancer therapy, we evaluated the effects of four representative retinoic acid metabolism blocking agents (RAMBAs, VN/14-1, VN/50-1, VN/66-1 and VN/69-1) on growth inhibition of oestrogen receptor positive (ER +ve, MCF-7 and T-47D) and oestrogen receptor negative (ER −ve, MDA-MB-231) human breast cancer cells. Additionally, we investigated the biological effects/molecular mechanism(s) underlying their growth inhibitory properties as well as their antitumour efficacies against MCF-7 and MCF-7Ca tumour xenografts in nude mice. We also assessed the effect of combining VN/14-1 and all-trans-retinoic acid (ATRA) on MCF-7 tumuor xenografts. The ER +ve cell lines were more sensitive (IC₅₀ values between 3.0 and 609 nM) to the RAMBAs than the ER −ve MDA-MB-231 cell line (IC₅₀=5.6–24.0 μM). Retinoic acid metabolism blocking agents induced cell differentiation as determined by increased expression of cytokeratin 8/18 and oestrogen receptor-α (ER-α). Similar to ATRA, they also induced apoptosis via activation of caspase 9. Cell cycle analysis indicated that RAMBAs arrested cells in the G1 and G2/M phases and caused significant downregulation (>80%) of cyclin D1 protein. In vivo, the growth of MCF-7 mammary tumours was dose-dependently and significantly inhibited (92.6%, P<0.0005) by VN/14-1. The combination of VN/14-1 and ATRA also inhibited MCF-7 breast tumour growth in vivo (up to 120%) as compared with single agents (P<0.025). VN/14-1 was also very effective in preventing the formation of MCF-7Ca tumours and it significantly inhibited the growth of established MCF-7Ca tumours, being as effective as the clinically used aromatase inhibitors, anastrozole and letrozole. Decrease in cyclin D1 and upregulation of cytokeratins, Bad and Bax with VN/14-1 may be responsible for the efficacy of this compound in inhibiting breast cancer cell growth in vitro and in vivo. Our results suggest that our RAMBAs, especially VN/14-1 may be useful novel therapy for breast cancer.

Alterations in plasma lipid profile patterns in head and neck cancer and oral precancerous conditions

BACKGROUND

The changes in lipid profile have long been associated with cancer because lipids play a key role in maintenance of cell integrity.

AIMS

The present study evaluated alterations in plasma lipid profile in untreated head and neck cancer patients as well as patients with oral precancerous conditions (OPC) and its association with habit of tobacco consumption.

MATERIAL AND METHODS

This hospital-based case control study included 184 head and neck cancer patients, 153 patients with OPC and 52 controls. Plasma lipids including: (i) Total cholesterol, (ii) LDL cholesterol (LDLC), (iii) HDL cholesterol (HDLC) (iv) VLDL cholesterol (VLDLC) and (v) triglycerides were analysed by spectrophotometric kits.

STATISTICAL ANALYSIS USED

Student's t-test was performed to compare mean values of the parameters.

RESULTS

A significant decrease in plasma total cholesterol and HDLC was observed in cancer patients (P=0.008 and P=0.000 respectively) as well as in patients with OPC (P=0.014 and P=0.000, respectively) as compared to the controls. The plasma VLDL and triglycerides levels were significantly lower in cancer patients as compared to the patients with OPC (P=0.04) and controls (P=0.059). The tobacco habituates showed lower plasma lipid levels than the non-habituates. Our data strengthen the evidence of an inverse relationship between plasma lipid levels and head and neck malignancies as well as OPC.

CONCLUSION

The lower levels of plasma cholesterol and other lipid constituents in patients might be due to their increased utilization by neoplastic cells for new membrane biogenesis. The findings strongly warrant an in-depth study of alterations in plasma lipid profile in head neck cancer patients.

Evaluation of serum sialic acid, sialyltransferase and sialoproteins in oral cavity cancer

OBJECTIVE

Altered glycosylation of glycoconjugates is among the important molecular changes that accompany malignant transformation. The aim of our study was to investigate clinical usefulness of circulatory levels of sialic acid, sialoproteins and sialyltransferase for early diagnosis and management of oral cavity cancer (OC) patients.

MATERIALS AND METHODS

Blood samples collected from 210 untreated OC patients, 100 patients with oral precancerous conditions (OPC) and 100 healthy males. OC patients were followed after initiation of anticancer treatment and 394 follow-up samples were also collected. Serum sialic acid levels were measured spectrophotometrically. Sialyltransferase activity was analysed using radioassay. Alpha 2-6 sialoproteins were isolated using lectin affinity chromatography.

RESULTS

Serum levels of free, protein bound and total sialic acid as well as their ratio with total proteins were significantly elevated in untreated OC patients compared with healthy individuals, patients with OPC as well as complete responders (CR). Levels of the markers were comparable between untreated OC patients and non-responders. We observed positive correlation between serum levels of the markers and extent of malignant disease. Serum sialyltransferase activity showed significant elevations in OC patients compared with the controls (P<0.001), patients with OPC (P<0.05) and CR (P<0.05). Higher sialic acid levels in OC patients at the time of diagnosis showed poor survival. The changes in serum proteins with terminal alpha 2-6 sialic acid correlated well with the alterations in the levels of sialic acid forms and sialyltransferase activity.

CONCLUSION

Our results confirmed the elevations in sialic acid and sialyltransferase levels in OC patients and suggested potential utility of these parameters in prognostication and treatment monitoring of this neoplasm. The alterations in these parameters in circulation were in accordance with the changes in alpha 2-6 sialylated proteins.

Serum glutathione-S-transferase and glutathione reductase activity in head and neck cancer patients

Glutathione, an antioxidant plays an important role in phase-II detoxification of carcinogens. The levels of reduced glutathione are maintained by glutathione-depleting as well as replenishing enzymes such as glutathione-s-transferase (GST) and glutathione reductase (GR), respectively. Pre and post treatment changes in GST and GR activities in head and neck cancer patients were analysed. Serum GST and GR were analysed from untreated head and neck cancer patients (PT) (n=146), controls with habit of tobacco (VHT) (n=25) as well as without (no) habit of tobacco (NHT) (n=25) and patients with oral precancerous conditions (OPC) (n=50). The cancer patients were followed-up after initiation of anticancer therapy. Follow-up blood samples were collected. Serum GST and GR activities were estimated by highly sensitive and specific spectrophotometric methods. Untreated cancer patients showed elevated mean serum GST and GR activities as compared to NHT. Patients with OPC had declined mean GST activity as compared to WHT and untreated cancer patients. Paired t-test revealed that complete responders (CR) showed significantly elevated GST levels and declined GR activities (p < 0.001) as compared to those in PT. No correlation was found between stage of the disease and GST, GR activity. Paired t-test showed significant decreased in GR activity in nonresponders (NR) treated with radiotherapy (p=0.01). The study suggested that analysis of glutathione and glutathione-depleting enzymes can be helpful for treatment monitoring of head and neck cancer patients.

16S rRNA gene sequencing for bacterial pathogen identification in the clinical laboratory

For many years, sequencing of the 16S ribosomal RNA (rRNA) gene has served as an important tool for determining phylogenetic relationships between bacteria. The features of this molecular target that make it a useful phylogenetic tool also make it useful for bacterial detection and identification in the clinical laboratory. Sequence analysis of the 16S rRNA gene is a powerful mechanism for identifying new pathogens in patients with suspected bacterial disease, and more recently this technology is being applied in the clinical laboratory for routine identification of bacterial isolates. Several studies have shown that sequence identification is useful for slow-growing, unusual, and fastidious bacteria as well as for bacteria that are poorly differentiated by conventional methods. The technical resources necessary for sequence identification are significant. This method requires reagents and instrumentation for amplification and sequencing, a database of known sequences, and software for sequence editing and database comparison. Commercial reagents are available, and laboratory-developed assays for amplification and sequencing have been reported. Likewise, there are an increasing number of commercial and public databases. Despite the availability of resources, sequence-based identification is still relatively expensive. The cost is significantly reduced only by the introduction of more automated methods. As the cost decreases, this technology is likely to be more widely applied in the clinical setting.

16S rRNA gene sequencing for bacterial pathogen identification in the clinical laboratory

For many years, sequencing of the 16S ribosomal RNA (rRNA) gene has served as an important tool for determining phylogenetic relationships between bacteria. The features of this molecular target that make it a useful phylogenetic tool also make it useful for bacterial detection and identification in the clinical laboratory. Sequence analysis of the 16S rRNA gene is a powerful mechanism for identifying new pathogens in patients with suspected bacterial disease, and more recently this technology is being applied in the clinical laboratory for routine identification of bacterial isolates. Several studies have shown that sequence identification is useful for slow-growing, unusual, and fastidious bacteria as well as for bacteria that are poorly differentiated by conventional methods. The technical resources necessary for sequence identification are significant. This method requires reagents and instrumentation for amplification and sequencing, a database of known sequences, and software for sequence editing and database comparison. Commercial reagents are available, and laboratory-developed assays for amplification and sequencing have been reported. Likewise, there are an increasing number of commercial and public databases. Despite the availability of resources, sequence-based identification is still relatively expensive. The cost is significantly reduced only by the introduction of more automated methods. As the cost decreases, this technology is likely to be more widely applied in the clinical setting.

Simultaneous determination of losartan and hydrochlorothiazide in combined dosage forms by first-derivative spectroscopy and high-performance thin-layer chromatography

Losartan (LST) is the first orally active nonpeptide angiotensin-II receptor antagonist with an improved safety and tolerability profile. It is prescribed alone or in combination with hydrochlorothiazide (HCTZ) for the treatment of moderate-to-severe hypertension. This paper describes the development of 2 methods that use different techniques, first-derivative spectroscopy and high-performance thin-layer chromatography (HPTLC), to determine LST and HCTZ in the presence of each other. LST and HCTZ in combined preparations were quantitated by using the first-derivative responses at 271.6 nm for LST and 335.0 nm for HCTZ in spectra of their solutions in water. The linearity ranges are 30-70 microg/mL for LST and 7.5-17.5 microg/mL for HCTZ with correlation coefficients of 0.9998 and 0.9997, respectively. In the HPTLC method, a mobile phase of chloroform-methanol-acetone-formic acid (7.5 + 1.5 + 0.5 + 0.03, v/v) and a prewashed Silica Gel G60 F254 TLC plate as the stationary phase were used to resolve LST and HCTZ in a mixture. Two well-separated and sharp peaks for LST and HCTZ were obtained at Rf values of 0.61+/-0.02 and 0.41+/-0.02, respectively. LST and HCTZ were quantitated at 254.0 nm. The linearity ranges obtained for the HPTLC method are 400-1200 and 100-300 ng/spot with corresponding correlation coefficients of 0.9944 and 0.9979, for LST and HCTZ, respectively. Both methods were validated, and the results were compared statistically. They were found to be accurate, specific, and reproducible. The methods were successfully applied to the estimation of LST and HCTZ in combined tablet formulations.

Epidemiological investigation of fluoroquinolone resistance in infections due to extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae

The incidence of infections due to extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae (ESBL-EK) has increased markedly in recent years. Treatment is difficult because of frequent multidrug resistance. Although fluoroquinolones offer effective therapy for ESBL-EK infections, their usefulness is threatened by increasing fluoroquinolone resistance. To identify risk factors for fluoroquinolone resistance in ESBL-EK infections, a case-control study of all patients with ESBL-EK infections from 1 June 1997 through 30 September 1998 was conducted. Of 77 ESBL-EK infections, 43 (55.8%) were resistant to fluoroquinolones. Independent risk factors for fluoroquinolone resistance were fluoroquinolone use (odds ratio [OR], 11.20; 95% confidence interval [CI], 1.99-63.19), aminoglycoside use (OR, 5.83; 95% CI, 1.12-30.43), and long-term care facility residence (OR, 3.39; 95% CI, 1.06-10.83). The genotypes of fluoroquinolone-resistant ESBL-EK isolates were closely related. Efforts should be directed at modification of these risk factors to preserve the utility of fluoroquinolones in the treatment of ESBL-EK infections.

Epidemiological investigation of fluoroquinolone resistance in infections due to extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae

The incidence of infections due to extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae (ESBL-EK) has increased markedly in recent years. Treatment is difficult because of frequent multidrug resistance. Although fluoroquinolones offer effective therapy for ESBL-EK infections, their usefulness is threatened by increasing fluoroquinolone resistance. To identify risk factors for fluoroquinolone resistance in ESBL-EK infections, a case-control study of all patients with ESBL-EK infections from 1 June 1997 through 30 September 1998 was conducted. Of 77 ESBL-EK infections, 43 (55.8%) were resistant to fluoroquinolones. Independent risk factors for fluoroquinolone resistance were fluoroquinolone use (odds ratio [OR], 11.20; 95% confidence interval [CI], 1.99-63.19), aminoglycoside use (OR, 5.83; 95% CI, 1.12-30.43), and long-term care facility residence (OR, 3.39; 95% CI, 1.06-10.83). The genotypes of fluoroquinolone-resistant ESBL-EK isolates were closely related. Efforts should be directed at modification of these risk factors to preserve the utility of fluoroquinolones in the treatment of ESBL-EK infections.

Extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae: risk factors for infection and impact of resistance on outcomes

The prevalence of antibiotic resistance among extended-spectrum beta-lactamase (ESBL)--producing Escherichia coli and Klebsiella pneumoniae has increased markedly in recent years. Thirty-three patients with infection due to ESBL-producing E. coli or K. pneumoniae (case patients) were compared with 66 matched controls. Total prior antibiotic use was the only independent risk factor for ESBL-producing E. coli or K. pneumoniae infection (odds ratio, 1.10; 95% confidence interval, 1.03--1.18; P=.006). Case patients were treated with an effective antibiotic a median of 72 hours after infection was suspected, compared with a median of 11.5 hours after infection was suspected for controls (P<.001). ESBL-producing E. coli or K. pneumoniae infection was associated with a significantly longer duration of hospital stay and greater hospital charges (P=.01 and P<.001, respectively). Finally, many ESBL-producing E. coli and K. pneumoniae isolates were closely related. ESBL-producing E. coli and K. pneumoniae infections have a significant impact on several important clinical outcomes, and efforts to control outbreaks of infection with ESBL-producing E. coli and K. pneumoniae should emphasize judicious use of all antibiotics as well as barrier precautions to reduce spread.

Performance of two rapid, single-use immunoassays for the detection of Clostridium difficile toxin A

Two rapid, single-use immunoassays for C. difficile toxin A, the Clearview C. DIFF A (Wampole Laboratories, Cranbury, N.J.) and the ImmunoCard Toxin A assays (Meridian Diagnostics Inc., Cincinnati, Ohio) were compared to the cytotoxin assay for their ability to detect C. difficile toxin in fecal specimens. A total of 537 specimens were tested and 47 (8.8%) were positive by the cytotoxin assay. The sensitivity, specificity, positive predictive value, and negative predictive value of the toxin A assays were as follows: 70.2% (95% CI, 57.1 to 83.3), 98.8% (95% CI, 97.8 to 99.8), 84.6% (95% CI, 73.3 to 95.9), and 97.2% (95% CI, 95.7 to 98.6) respectively for the Clearview assay; and 74.5% (95% CI, 62.0 to 86.9), 99.0% (95% CI, 98.1 to 99.9), 87.5% (95% CI, 77.3 to 97.8), and 97.6% (95% CI, 96.2 to 98.9) respectively for the ImmunoCard assay. Both toxin A assays are less sensitive than the cytotoxin assay, however, these assays offer a rapid and easy-to-perform test that may be used in conjunction with the cytotoxin assay for laboratory confirmation of C. difficile-associated disease.

Effects of storage and reperfusion oxygen content on substrate metabolism in the isolated rat lung

BACKGROUND

Lung transplantation requires a period of storage and ischemia; we examined the largely unknown effects of that period on intermediary metabolism.

METHODS

Two groups of isolated rat lung blocks (n = 16 each) were flushed with Euro-Collins solution and harvested. The lung blocks were immediately ventilated and either perfused for 30 minutes with an erythrocyte-based solution containing carbon 13 labeled substrates (group 1) or stored for 6 hours at 1 degree C and then reperfused (group 2). Half of each group was reperfused at a physiologic Po2 the other half at high Po2. Analysis of carbon 13 isotopomers was performed to determine substrate utilization through aerobic pathways in lung tissue.

RESULTS

Lungs from both groups oxidized all major substrates. The contribution of fatty acids to acetylcoenzyme acid oxidized in the citric acid cycle was significantly higher in group 2 than in group 1 (31.3% +/- 2.2% versus 22.0% +/- 2.1%, p < 0.05). Perfusate Po2 did not affect substrate preference. Gas exchange was worse in stored lungs.

CONCLUSIONS

After a period of hypothermic ischemia and storage, substrate preference in lung tissue exhibits a switch towards fatty acids. As fatty acid oxidation occurring after ischemia is deleterious in other organs, strategies to inhibit this process in stored lungs may warrant further investigation.

Evaluation of serum alkaline DNase activity in treatment monitoring of head and neck cancer patients

Our previously published data on breast cancer suggest that serum alkaline DNase, a known circulating tumour marker, can be used for treatment monitoring of cancer patients. Serum alkaline DNase activities were analyzed in 215 untreated head and neck cancer patients. The enzyme activity ranged from 0.17 to 97.97 IKU/l in untreated cancer patients. Responders (n = 314) showed significantly elevated activity of alkaline DNase as compared to untreated cancer patients (p < 0.001). While non-responders (n = 168) showed comparable activity with untreated cancer patients. Serum alkaline DNase activities were significantly elevated in responders as compared to non-responders (p < 0.001). Our clinical studies during follow-up of patients indicated that the variations in serum alkaline DNase activities in individual patients correlate closely with response to therapy. Serum alkaline DNase also appeared to be useful in predicting treatment response in the long-term follow-up of patients. Serum alkaline DNase was systematically examined as a possible indicator for recurrence in patients under complete remission. In conclusion, serum alkaline DNase may be useful as a treatment monitoring in patients with head and neck malignancies.

Sequence-based identification of Mycobacterium species using the MicroSeq 500 16S rDNA bacterial identification system

We evaluated the MicroSeq 500 16S rDNA Bacterial Sequencing Kit (PE Applied Biosystems), a 500-bp sequence-based identification system, for its ability to identify clinical Mycobacterium isolates. The organism identity was determined by comparing the 16S rDNA sequence to the MicroSeq database, which consists primarily of type strain sequences. A total of 113 isolates (18 different species), previously recovered and identified by routine methods from two clinical laboratories, were analyzed by the MicroSeq method. Isolates with discordant results were analyzed by hsp65 gene sequence analysis and in some cases repeat phenotypic identification, AccuProbe rRNA hybridization (Gen-Probe, Inc., San Diego, Calif.), or high-performance liquid chromatography of mycolic acids. For 93 (82%) isolates, the MicroSeq identity was concordant with the previously reported identity. For 18 (16%) isolates, the original identification was discordant with the MicroSeq identification. Of the 18 discrepant isolates, 7 (six unique sequences) were originally misidentified by phenotypic analysis or the AccuProbe assay but were correctly identified by the MicroSeq assay. Of the 18 discrepant isolates, 11 (seven unique sequences) were unusual species that were difficult to identify by phenotypic methods and, in all but one case, by molecular methods. The remaining two isolates (2%) failed definitive phenotypic identification, but the MicroSeq assay was able to definitively identify one of these isolates. The MicroSeq identification system is an accurate and rapid method for the identification of Mycobacterium spp.

Bacteremia caused by a novel isolate resembling leptotrichia species in a neutropenic patient

We report a case of Leptotrichia species bacteremia in a patient undergoing treatment for acute myelogenous leukemia. Like previously reported Leptotrichia species, this is a gram-variable, pleomorphic rod that is catalase negative and utilizes glucose and sucrose. However, it is more fastidious than previously reported isolates of Leptotrichia and may represent a novel species.

Probing the yeast phase-specific expression of the CBP1 gene in Histoplasma capsulatum

Histoplasma capsulatum is a pathogenic fungus that exists in two distinct forms. The saprophytic mycelial phase inhabits moist soil environments; once inhaled, hyphae and conidia convert to a unicellular yeast phase that is capable of parasitizing macrophage phagolysosomes. Yeasts cultures, but not mycelial cultures, release large quantities of a calcium-binding protein (CBP) which may be important in calcium acquisition during intracellular parasitism. In this study, we show that the gene encoding CBP (CBP1) is transcriptionally regulated. To identify promoter sequences that are important for yeast phase-specific activity, we created a series of fusions between successively truncated CBP1 5' untranslated regulatory sequences and the Escherichia coli lacZ gene. The fusions were constructed on a telomeric shuttle plasmid that can replicate autonomously in the fungus. By assaying for beta-galactosidase activity from H. capsulatum transformants, we identified a 102-bp region that mediates promoter activation and yeast phase promoter activity. Base pair substitution analysis suggests that the sequences between 839 and 877 bp upstream of the start codon are the most important for this positive regulation.

Synthesis and structure-activity relationships of a series of anxioselective pyrazolopyridine ester and amide anxiolytic agents

A series of 1-substituted 4-amino-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid esters and amides were synthesized and screened for anxiolytic activity in the shock-induced suppression of drinking (SSD) test. The compounds were also tested for their ability to displace [3H]flunitrazepam (FLU) from brain benzodiazepine (BZ) binding sites. Many compounds were active in these screens and, additionally, demonstrated a selectivity for the type 1 BZ (BZ1) receptor over the type 2 BZ (BZ2) receptor as indicated by Hill coefficients significantly less than unity and by analysis of [3H]FLU binding results from different brain regions. Based on the results of structure-activity studies of these compounds, a hypothesis was proposed to explain the structural features necessary for optimal interaction with brain BZ receptors. A detailed pharmacological evaluation of one of the most potent behaviorally active compounds (27) demonstrated it to be BZ1 selective; also, in comparison to diazepam, 27 showed minimal sedative and alcohol interactive properties at therapeutically effective doses.

Meropenem: evidence of lack of proconvulsive tendency in mice

The proconvulsive tendency of the novel carbapenem, meropenem was compared to that of imipenem, alone and in combination with cilastatin. The potentiation of metrazole-induced convulsions in mice was measured. Both imipenem and imipenem/cilastatin caused significant potentiation of metrazole-induced convulsions at a dose of 200 mg/kg, i.v. In contrast, meropenem (50-400 mg/kg, iv) failed to exhibit any significant potentiation of metrazole-induced seizures.

A simple and rapid method of inducing physical dependence with benzodiazepines in mice

Physical dependence was rapidly induced in mice by administering diazepam intraperitoneally twice daily using an incremental dosing regimen (50 to 450 mg/kg) for nine consecutive days. Withdrawal was induced (24 hr after the last dose) by administration of a benzodiazepine antagonist, RO-15-1788 (10 mg/kg, IP). All of the mice exhibited clear-cut withdrawal symptoms (i.e., convulsions) within minutes of antagonist treatment. This method offers a simple, reliable, high throughput procedure for the assessment of benzodiazepine-like physical dependence liability and withdrawal, and it would be useful for screening purposes.

Preclinical studies with pyrazolopyridine non-benzodiazepine anxiolytics: ICI 190,622

Tracazolate is a pyrazolopyridine anxiolytic that enhances the binding of [3H]-flunitrazepam [( 3H]FLU) to brain tissue. The discovery that a metabolite of tracazolate, desbutyltracazolate, was a weak inhibitor of [3H]FLU binding led to the synthesis of a series of potent anxiolytics. From this series, ICI 190,622 emerged as a viable drug candidate, being a potent anxiolytic in rats and monkeys. This anxiolytic agent appears to produce only minimal sedation. Furthermore, ICI 190,622 appears less likely to potentiate the actions of ethanol than diazepam. ICI 190,622 is also a potent anticonvulsant (anti-metrazol ED50 = 1.1 mg/kg, PO) in rodents. Neurochemically, ICI 190,622 is similar to the benzodiazepine anxiolytics. In vitro, ICI 190,622 competitively inhibited [3H]FLU binding in cerebral cortex with an IC50 of 81 nM and was 4.3-fold more potent in the cerebellum (IC50 = 19 nM). This suggests a selectivity for the Type 1 benzodiazepine binding site. In contrast, diazepam showed similar affinities in both regions (cerebral cortex = 7 nM and cerebellum = 9 nM). Following oral administration, ICI 190,622 displaced [3H]FLU binding from cerebellar membranes more potently than diazepam (ED50 = 3 and 6 mg/kg, respectively, 1 hour after administration). Thus, ICI 190,622 should be an effective anxiolytic with significant advantages over benzodiazepines.

Malignant fibrous histiocytoma of the second metacarpal

A case of low grade malignant fibrous histiocytoma (MFH) arising from a metacarpal bone in a 21 year old African female is presented. The rarity of this disorder is emphasized with review of the relevant literature.

Early congenital syphilis: clinico-radiologic features in 202 patients

Venereal syphilis is highly prevalent among women of child-bearing age in Zambia. It is estimated to contribute 25-30% of the perinatal mortality rate of 50 per 1,000 births at the University Teaching Hospital in Lusaka. Because of multisystem involvement, early congenital syphilis, the offshoot of maternal syphilis, has varied criteria for its diagnosis. Therefore, in an attempt to draw guidelines for an easier and more reliable diagnosis, the authors analyzed the clinico-radiologic features of congenital syphilis in 202 patients. Although all infants were under the age of six months, there were several significant differences in the manifestations of the disease among neonates and the postneonates. The younger infants had a higher incidence of jaundice and mortality, whereas joint swellings, skin rash, snuffles, anemia, and periosteal reaction visible in x-rays of long bones were typical findings among the older group. The radiologic changes were seen in greater than 95% of patients in both groups. About 84% of mothers had attended prenatal clinics, but less than 20% of the women had been tested for syphilis. Since early congenital syphilis is common in many parts of the world and since all serologic tests have limitations, awareness of appropriate diagnostic criteria is recommended for all medical personnel.

Pharmacology of pyrazolopyridines

Pyrazolopyridines (PZP's) in general represent a chemically unique class of non-sedative anxiolytic agents. Tracazolate (ICI 136,753) is a member of pyrazolopyridine series that has shown anxiolytic properties in animal models. Tracazolate demonstrates a wider separation between sedative and therapeutic doses than do benzodiazepines. In addition, tracazolate appears to cause fewer adverse interactions than the benzodiazepines in combination with barbiturates and alcohol. In interaction studies, tracazolate potentiated both the antimetrazol and anticonflict effects of chlordiazepoxide. Pyrazolopyridines cause enhancement of both 3H-flunitrazepam (3H-FLU) and 3H-GABA to their binding sites in brain. The enhancement of 3H-FLU binding by PZP's and GABA are additive and reversed by bicuculline. The enhancement of 3H-GABA binding by PZP's and benzodiazepines are additive and reversed by picrotoxin. It is hypothesized that the action of PZP's, and particularly tracazolate, may be related to their effects upon a GABA-stimulated chloride ionophore site. Finally, benzodiazepine antagonists (e.g., RO-15 1788) fail to reverse either the anxiolytic properties of 3H-FLU enhancers or their 3H-GABA binding enhancement effects. In contrast, benzodiazepine antagonists readily reverse the anxiolytic effects of benzodiazepines and non-benzodiazepines which cause 3H-FLU displacement. These data suggest that tracazolate, a non-benzodiazepine, has a pharmacological profile suggestive of novel anxiolytic activity.

Neurochemical characteristics of rats distinguished as benzodiazepine responders and non-responders in a new conflict test

Using a new rat conflict test it was found that 30% of the subjects failed to respond to benzodiazepines and other anxiolytic agents. This value is similar to that reported using more classical procedures such as the Geller-Seifter and Vogel conflict tests. Biochemical analysis of various brain regions from responder (R) and non-responder (NR) subjects revealed no significant differences in 5-HT1, 5-HT2, GABA receptor binding or GABA-activated benzodiazepine binding. However, a small, but significant, increase in basal benzodiazepine binding was noted in the hippocampus of NR rats. These findings suggest that the insensitivity of these animals to anxiolytics is probably unrelated to an alteration in serotonin, GABA or benzodiazepine binding sites in brain.

Novel non-benzodiazepine anxiolytics

Several new non-benzodiazepine anxiolytics are reported. These include tracazolate, zopiclone, CL218,872, CGS9896, buspirone, MK-801 and fenobam. A comparison of anticonflict effects and propensity to cause sedation and potentiate the actions of ethanol is given as well as their effects upon the binding of [3H]flunitrazepam in vitro. Their anxiolytic properties after treatment with the benzodiazepine antagonist, RO15-1788, are reported also. Tracazolate shows a wide separation between anxiolytic activity and ability to cause sedation and to potentiate alcohol. It enhanced binding of [3H]-flunitrazepam in contrast to benzodiazepines which displace it. Buspirone was without anticonflict activity and had no effect on benzodiazepine binding while fenobam and MK-801, also without effect on binding, showed large and small differences on causing sedation and potentiating alcohol respectively. Among the displacers of [3H]flunitrazepam zopiclone showed diminished sedation liability, compared to diazepam, as did CL218,872 and CGS9896. Zopiclone caused potentiation of ethanol however, at doses close to anxiolytic doses, while CL218,872 and CGS9896 showed a wider safety margin for potentiation of ethanol compared to anxiolytic doses. The drug RO15-1788 antagonised the anticonflict effects of benzodiazepine displacers and had no effects upon the other agents studied.

Differential antagonism of the anticonflict effects of typical and atypical anxiolytics

Selected benzodiazepine and non-benzodiazepine agents were studied alone or in the presence of benzodiazepine antagonists in the shock-induced suppression of drinking (SSD) procedure in rats. The disinhibitory activity of chlordiazepoxide, CL218,872, zopiclone and CGS 9896 was antagonized by two benzodiazepine antagonists, RO-15-1788 and CGS 8216. In contrast, the disinhibitory activity of fenobam, meprobamate, phenobarbital and tracazolate was not antagonized by either RO 15-1788 and CGS 8216. From these data it is apparent that the anticonflict activity of agents that bind to benzodiazepine receptors is blocked by benzodiazepine antagonists. In contrast, the activity of anxiolytics that are not displacers are unaffected even at higher doses.

A sensitive and selective monkey conflict test

A conflict model is described in which clinically effective antianxiety agents exhibit pronounced anticonflict activity. Male squirrel monkeys were trained to depress a bar for 5 sec to obtain food reinforcement. The 6 hr test session was comprised of an initial 3 hr period in which each 5 sec response was punished and then a 3 hr unpunished period. Trained monkeys would rarely be shocked and would make most of their responses during the non-punished period. Both benzodiazepine (chlordiazepoxide and diazepam) and non-benzodiazepine (meprobamate and phenobarbital) anxiolytics produced pronounced and unequivocal increases in punished responding. Other psychoactive agents (damphetamine, chlorpromazine, ethanol, morphine, amitriptyline and imipramine) did not produce an increase in punished responding. Sensitivity (i.e., large magnitude effects), selectivity, stable baseline performance and fully automated features make this test useful in identifying potential anxiolytic agents in primates.

Pharmacological properties of tracazolate: a new non-benzodiazepine anxiolytic agent

Tracazolate (ICI 136,753, 4-butylamino-1-ethyl-6-methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester) demonstrated dose-related anticonflict activity in rats and mice. The potency of tracazolate appears to be one-quarter to one-half that of chlordiazepoxide. No tolerance to the anticonflict activity of either tracazolate or chlordiazepoxide was evident following 12 consecutive days of treatment. Tracazolate exhibits a much greater separation between sedative and therapeutic doses than does chlordiazepoxide. Furthermore, based on rodent studies, tracazolate should be much less likely than the benzodiazepines to potentiate the actions of barbiturates and ethanol in man. Tracazolate potentiated both the anticonvulsant and anxiolytic effects of chlordiazepoxide in rodents. Unlike benzodiazepines, tracazolate enhances the binding of benzodiazepines to its receptor site. These results suggest that tracazolate is a novel agent with potential clinical utility as an anxiolytic drug.

Effects of isoproterenol and chlordiazepoxide on drinking and conflict behaviors in rats

Isoproterenol, a beta-adrenergic agents, induced drinking in water-satiated rats. Isopropeternol exhibited significant anti-conflict activity on water-deprived rats in the Shock-induced Suppression of Drinking (SSD) procedure. Chlordiazepoxide (CDP), at the highest dose tested, also increased drinking in non-deprived naive rats. As expected, CDP demonstrated highly significant anti-conflict activity in thirsty rats (SSD test). These results suggest that in conflict procedures, where food or water is used as a reward, agents that affect the consumatory drive mechanisms could show up as "false positives." Moreover, agents that affect primary drives (e.g., CDP), in addition to their anti-anxiety activity, could show additive activity in such conflict procedures.

Benzodiazepine blockade of passive-avoidance task in mice: a state-dependent phenomenon

Four benzodiazepines (diazepam, chlordiazepoxide, halazepam, lorazepam) were tested for their effects on the acquisition of a passive-avoidance task in mice. This was done to determine whether amnesic effects, as reported in humans after diazepam and lorazepam, could be demonstrated by blockade of passive-avoidance responding in mice and, if so, to investigate the possible causes of the blockade by studying the relationships between the blockade and times of drug administration. Each of these benzodiazepines, at doses that did not alter overt behavior, blocked acquisition of the passive-avoidance response when they were administered to mice prior to the training session, but not when they were administered after the training session or prior to testing 24 h later. The block of avoidance responding was reversed, however, when the drugs were administered prior to both training and test sessions. These results suggest that state-dependent learning occurred; i.e., apparent amnesia occurred in the test session with untreated mice that had undergone passive-avoidance learning 24 h earlier under the influence of drug.