Impact of operative time on early joint infection and deep vein thrombosis in primary total hip arthroplasty.

PURPOSE: Infections and deep vein thrombosis (DVT) after total hip arthroplasty (THA) are challenging problems for both the patient and surgeon. Previous studies have identified numerous risk factors for infections and DVT after THA but have often been limited by sample size. We aimed to evaluate the effect of operative time on early postoperative infection as well as DVT rates following THA. We hypothesized that an increase in operative time would result in increased odds of acquiring an infection as well as a DVT. METHODS: We conducted a retrospective analysis of prospectively collected data using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database from 2006 to 2015 for all patients undergoing primary THA. Associations between operative time and infection or DVT were evaluated with multivariable logistic regressions controlling for demographics and several known risks factors for infection. Three different types of infections were evaluated: (1) superficial surgical site infection (SSI), an infection involving the skin or subcutaneous tissue, (2) deep SSI, an infection involving the muscle or fascial layers beneath the subcutaneous tissue, and (3) organ/space infection, an infection involving any part of the anatomy manipulated during surgery other than the incisional components. RESULTS: In total, 103,044 patients who underwent THA were included in our study. Our results suggested a significant association between superficial SSIs and operative time. Specifically, the adjusted odds of suffering a superficial SSI increased by 6% (CI=1.04-1.08, p<0.0001) for every 10-minute increase of operative time. When using dichotomized operative time (<90minutes or >90minutes), the adjusted odds of suffering a superficial SSI was 56% higher for patients with prolonged operative time (CI=1.05-2.32, p=0.0277). The adjusted odds of suffering a deep SSI increased by 7% for every 10-minute increase in operative time (CI=1.01-1.14, p=0.0335). No significant associations were detected between organ/space infection, wound dehiscence, or DVT and operative time either as continuous or as dichotomized. CONCLUSION: Prolonged operative times (>90min) are associated with increased rates of superficial SSIs, but not deep SSIs, organ/space infections, wound dehiscence, or DVT. LEVEL OF EVIDENCE: III.

Children with a history of atypical febrile seizures show abnormal steady state visual evoked potential brain responses.

Atypical febrile seizures (FSs) are considered a risk factor for the onset of epilepsy in later life as well as for potential cognitive impairment. However, distinctive characteristics defining the group of children at risk for negative outcomes are not well established. In the following study, children from 6 to 59 months with a history of atypical FSs were investigated using steady state visual evoked potentials (ssVEP), a brain response known to increase with age. Abnormally, low theta and alpha ssVEP brain responses were found in children with a history of atypical FSs.

Metformin directly inhibits ghrelin secretion through AMP-activated protein kinase in rat primary gastric cells.

The antidiabetic drug Metformin causes weight loss in both diabetic and non-diabetic individuals. Metformin treatment is also associated with lower circulating levels of the orexigenic hormone ghrelin. To test whether Metformin directly affects ghrelin cells, rat primary stomach cells were treated with Metformin and the levels of ghrelin secretion, proghrelin gene expression and activation of adenosine monophosphate-activated protein kinase (AMPK) were examined. Metformin significantly reduced ghrelin secretion and proghrelin mRNA production and both these effects were blocked by co-incubation with the AMPK inhibitor compound C. Furthermore, the AMPK activator 5-amino-1-ß-D-ribofuranosyl-imidazole-4-carboxamide (AICAR) significantly inhibited ghrelin secretion. Additionally, ghrelin cells were shown to express AMPK. Finally, Metformin treatment caused a significant increase in the level of phosphorylated (active) AMPK. Our results show that Metformin directly inhibits stomach ghrelin production and secretion through AMPK. This reduction in ghrelin secretion may be one of the key components in Metformin's mechanism of weight loss.

The superiority of antidepressant medication to cognitive behavior therapy in melancholic depressed patients: a 12-week single-blind randomized study.

OBJECTIVE: To pursue the previously long-standing but formally untested clinical view that melancholia is preferentially responsive to antidepressant medication in comparison with psychotherapy [specifically Cognitive Behavior Therapy (CBT)]. Second, to determine whether a broader action antidepressant medication sequencing regimen is superior to a Selective Serotonin Reuptake Inhibitor (SSRI) alone. METHOD: We sought to recruit a large sample of participants with melancholic depression for a 12-week trial but inclusion criteria compromised recruitment and testing the second hypothesis. The first hypothesis was evaluated by comparing 18 participants receiving antidepressant medication to 11 receiving CBT. Primary study measures were the Hamilton Rating Scale for Depression (HAM-D) and the Hamilton Endogenous Subscale (HES), rated blindly, while several secondary measures also evaluated outcome. RESULTS: Participants receiving medication had a superior 12-week outcome to those receiving CBT, with significant differences present on primary measures as early as 4 weeks. At trial conclusion, the percentage improvement in HAM-D scores was 61.1% vs. 34.4%, respectively [Number Needed to Treat (NNT) = 3.7] and with those in receipt of medication returning non-significantly higher HAM-D responder (66.6% vs. 36.4%, NNT = 2.8) and remission (66.7% vs. 45.4%, NNT = 4.7) rates. CONCLUSION: As the sample size was small and participants evidenced only moderate levels of depression severity, the study risked being underpowered and idiosyncratic. Despite the small sample, the superiority of antidepressant medication to CBT in those with a melancholic depression was distinctive in this pilot study.

Vaccination of BALB/c mice with an avirulent Mycoplasma pneumoniae P30 mutant results in disease exacerbation upon challenge with a virulent strain.

Mycoplasma pneumoniae is a significant human respiratory pathogen that causes high morbidity worldwide. No vaccine to prevent M. pneumoniae infection currently exists, since the mechanisms of pathogenesis are poorly understood. To this end, we constructed a P30 cytadhesin mutant (P-130) with a drastically reduced capacity for binding to erythrocytes and an inability to glide on glass substrates. This mutant was determined to be avirulent and cannot survive in the lungs of BALB/c mice. We also ascertained that the previously identified P30 gliding motility mutant II-3R is avirulent and also cannot be recovered from the lungs of mice after infection. Mutant P130 was then assessed for its efficacy as a live attenuated vaccine candidate in mice after challenge with wild-type M. pneumoniae. After vaccination with the P-130 P30 mutant, mice showed evidence of exacerbated disease upon subsequent challenge with the wild-type strain PI1428, which appears to be driven by a Th17 response and corresponding eosinophilia. Our results are in accordance with other reports of vaccine-induced disease exacerbation in rodents and emphasize the need to better understand the basic mechanisms of M. pneumoniae pathogenesis.

GIS-based measures of environmental equity: exploring their sensitivity and significance.

In order to determine whether principles of environmental justice have been violated, a large number of empirical studies have been carried out to ascertain whether minority and low-income populations are disproportionately exposed to industrial pollution. This study provides a comparative evaluation of two commonly employed proximity measures in GIS-based environmental equity assessment, examining their influence on the results of the analysis, and proposes a methodology for evaluating the significance of these results. 1990 census data on population characteristics and data from the 1995 EPA's toxic release inventory (TRI) for the City of Minneapolis, MN are used. These results also allow a preliminary assessment of environmental equity/inequity in potential exposure to airborne toxic chemicals for racial minorities, poor people and children in Minneapolis. In the third part of the paper we develop and employ a geographic randomization methodology for assessing the significance of these results.

Histopathologic practices for esophageal biopsy specimens: survey results and implications for surveillance in patients with Barrett's esophagus.

A clinically valuable interpretation of esophageal biopsy specimens begins with well-prepared histologic sections. This may be especially true for reflux esophagitis and Barrett's glandular dysplasia. To determine exactly which histologic procedures are used by experts in gastrointestinal pathology, a checklist survey was mailed to 50 members of the Gastrointestinal Pathology Society. Responses were received from 42 (84%). Formalin, used 80% of the time, is overwhelmingly the most popular fixative. Orientation of biopsy material before further processing is performed in 36% of the institutions, most often (53%) by an endoscopy technician. The most frequently used (60%) substrate for orientation is filter material. The most common (83%) routine procedure uses only H&E staining. Others routinely add a mucin reaction to the H&E. Eleven different practices for sectioning are used; the most common (43%) is serial step sectioning at 3 levels. One third of the responders had a formal surveillance program for patients with Barrett's esophagus. For esophageal biopsy specimens, a broad spectrum of histologic practices exists. Trends for the more complex histotechnologic procedures to be used by those involved in screening for dysplastic Barrett's epithelium are evident.

Luciferin-luciferase assay of adenosine triphosphate from bacteria: a comparison of dimethylsulphoxide (DMSO) and acetone with other solvents.

The extraction of adenosine triphosphate (ATP) from six strains of bacteria, chosen for differences in cell-wall composition and habitat, was performed. The solvents were two in common use, Tris-ethylenediaminetetraacetate (Tris-EDTA) and trichloroacetic acid (TCA), and two promising, though less utilized solvents, dimethylsulphoxide (DMSO) and acetone. ATP was determined by the luciferin-luciferase reaction. Of the solvents used, DMSO and acetone were the most effective considering the different kinds of bacteria tested and, of these two, DMSO was the most convenient to use. Tris-EDTA was not as effective as the other solvents tested and TCA, which was effective with most strains, gave low yields when used with cultures grown in artificial seawater broth. Internal standards were used to determine if there were substances present that could inhibit the reaction of released ATP with the luciferin-luciferase reagent. Extracts of ATP, stored at -20 degrees C, were stable for up to 3 weeks.

The mutagenicity of a Prudhoe Bay crude oil and its residues from an experimental in situ burn.

Fresh and weathered Prudhoe Bay crude oil as well as residues from its combustion were tested for mutagenicity using strain TA98 in the Ames Salmonella typhimurium/liver microsome test. Because of the toxicity of the oils involved, mutagenic effects were clearly visible only at very low concentrations. All samples were found to be mutagenic, with precipitated plume having the greatest activity followed by the burn residue, the weathered oil, and fresh crude, respectively. The most polar components of the neutral fraction of the samples displayed the greatest mutagenicity.

City size distributions and spatial economic change.

"The concept of the city size distribution is criticized for its lack of consideration of the effects of interurban interdependencies on the growth of cities. Theoretical justifications for the rank-size relationship have the same shortcomings, and an empirical study reveals that there is little correlation between deviations from rank-size distributions and national economic and social characteristics. Thus arguments suggesting a close correspondence between city size distributions and the level of development of a country, irrespective of intranational variations in city location and socioeconomic characteristics, seem to have little foundation." (summary in FRE, ITA, JPN, )