Ductal Carcinoma In Situ with Microinvasion on Core Biopsy: Evaluating Tumor Upstaging Rate,Lymph Node Metastasis Rate,and Associated Predictive Variables

Annals of Surgical Oncology - The role of sentinel lymph node biopsy (SLNB) when ductal carcinoma in situ with microinvasion (DCISM) is identified on core biopsy is unclear. Our aim was to assess...     

The effect of placental removal method on the incidence of postcesarean infections

OBJECTIVE: Our purpose was to determine whether the incidence of postoperative endometritis and wound infection is associated with the method of placental removal at the time of cesarean section.STUDY DESIGN: Parturients undergoing cesarean delivery were prospectively randomized to have the placenta removed manually or spontaneously. Patients were excluded from participation if they had received intrapartum prophylactic antibiotics or had been determined to have chorioamnionitis. After delivery of the infant women in the manual group had the placenta extracted by the primary surgeon, whereas women in the spontaneous group had the placenta delivered by gentle traction on the umbilical cord. All study subjects received perioperative prophylactic antibiotics. The primary outcome variable was a postcesarean infection, defined as postcesarean endometritis or wound cellulitis requiring drainage and antibiotic therapy.RESULTS: A total of 333 women were enrolled in the investigation, with 165 assigned to the manual removal group and 168 allocated to have spontaneous removal. There were no statistically significant differences in mean gestational age, frequency or duration of ruptured membranes, frequency or duration of labor, or mean number of vaginal examinations between the two study groups. Postoperative infections occurred in 25 of 168 (15%) women in the spontaneous delivery group compared with 44 of 165 (27%) women in which the placenta was manually extracted (relative risk 0.6, 95% confidence interval 0.4 to 0.9, p = 0.01). Subset analysis of patients delivered with ruptured membranes similarly demonstrated a statistically significant reduction in the incidence of postoperative infections with spontaneous placental removal compared with manual extraction (20% vs. 38%, relative risk 0.5, 95% confidence interval 0.3 to 0.9, p = 0.02). There was a similar trend toward a reduction in postdelivery infections associated with spontaneous placental removal in women with intact membranes; however, this difference did not attain statistical significance.CONCLUSIONS: Spontaneous delivery of the placenta after cesarean delivery is associated with a decrease in the incidence of postcesarean infections. (Am J Obstet Gynecol 1997;176:1250-4.)     

Diagnosis of perirenal fibrosis by MR imaging

A case of retroperitoneal perirenal fibrosis resulting in bilateral proximal ureteral obstruction is reported. Magnetic resonance imaging provided tissue specific diagnosis of the disease.     

Comparison of MICs of ceftiofur and other antimicrobial agents against bacterial pathogens of swine from the United States, Canada, and Denmark.

The MICs of ceftiofur and other antimicrobial agents, tested for comparison, for 515 bacterial isolates of pigs from the United States, Canada, and Denmark with various diseases were compared. The organisms tested included Actinobacillus pleuropneumoniae, Escherichia coli, Pasteurella multocida, Salmonella choleraesuis, Salmonella typhimurium, Streptococcus suis, Streptococcus dysgalactiae subsp. equisimilis, Streptococcus equi subsp. equi, and Streptococcus equi subsp. zooepidemicus. In addition to ceftiofur, the following antimicrobial agents or combinations were tested: enrofloxacin, ampicillin, sulfamethazine, trimethoprim-sulfadiazine (1:19), erythromycin, lincomycin, spectinomycin, lincomycin-spectinomycin (1:8), tilmicosin, and tetracycline. Tilmicosin was only tested against the U.S. isolates. Overall, ceftiofur and enrofloxacin were the most active antimicrobial agents tested against all isolates, with MICs inhibiting 90% of isolates tested (MIC90s) of < or = 2.0 and < or = 1.0 microgram/ml, respectively. Erythromycin, sulfamethazine, spectinomycin, and lincomycin demonstrated limited activity against all of the organisms tested, with MIC90s of > or = 8.0, > or = 256.0, > or = 32.0, and > or = 16.0 micrograms/ml, respectively. Trimethoprim-sulfadiazine was active against isolates of A. pleuropneumoniae, S. choleraesuis, S. typhimurium, P. multocida, S. equi, and S. suis (MIC90s, < or = 0.5 microgram/ml) but was less active against the E. coli strains tested (MIC90, > 16.0 micrograms/ml). Ampicillin was active against the P. multocida, S. suis, and S. equi isolates tested (MIC90s, 0.5, 0.06, and 0.06 micrograms/ml, respectively) and was moderately active against S. typhimurium (MIC90s, 2.0 micrograms/ml). However, this antimicrobial agent was much less active when it was tested against A. pleuropneumoniae, S. cholerae-suis, and E. coli (MIC90s, 16.0, > 32.0, and 32.0 micrograms/ml, respectively). Against the U.S. isolates of A. pleuropneumoniae and P. multocida, tilmicosin was moderately active (MIC90s, 4.0 and 8.0 micrograms/ml, respectively). However, this compound was not active against the remaining U.S. isolates (MIC90s, > 64.0 micrograms/ml). Differences in the MICs from one country to another were not detected with enrofloxacin, ceftiofur, or lincomycin for the strains tested, but variations in the MICs of the remaining antimicrobial agents were observed.     

Identification of veterinary pathogens by use of commercial identification systems and new trends in antimicrobial susceptibility testing of veterinary pathogens.

Veterinary diagnostic microbiology is a unique specialty within microbiology. Although isolation and identification techniques are similar to those used for human pathogens, many veterinary pathogens require unique cultivation or identification procedures. Commercial identification systems provide rapid, accurate identification of human pathogens. However, the accuracy of these systems with veterinary pathogens varies widely depending on the bacterial species and the host animal from which it was isolated. Increased numbers of veterinary strains or species in the data bases of the various systems would improve their accuracy. Current procedures and interpretive criteria used for antimicrobial susceptibility testing of veterinary pathogens are based on guidelines used for human pathogens. The validity of these guidelines for use with veterinary pathogens has not been established. As with fastidious human pathogens, standardized methodologies and quality control isolates are needed for tests of organisms such as Actinobacillus pleuropneumoniae and Haemophilus somnus. Furthermore, interpretive criteria for veterinary antimicrobial agents based on the MIC for veterinary pathogens, the pharmacokinetics of the antimicrobial agent in the host animal, and in vivo efficacy of the antimicrobial agent are needed. This article reviews both the commercial identification systems evaluated with veterinary pathogens and current methods for performing and interpreting antimicrobial susceptibility tests with veterinary pathogens. Recommendations for future improvements in both areas are discussed.     

Response of tanycytes of rat median eminence to intraventricular administration of colchicine and vinblastine.

The effects of colchicine and vinblastine on tanycytes of the rat median eminence have been studied using the electron microscope. Colchicine and vinblastine were administered by intraventricular cannulation into the third ventricle and demonstrated distinct morphological effects on tanycyte microtubules. Highest drug doses administered were 50.0 mug in 5.0 mul of saline initially, followed by an additional 50.0 mug of these agents infused in a volume of 13.0 mul saline over an hour. Colchicine treatment resulted in the formation of large crystalloids within tanycytes, coincident with the disappearance of microtubules, all along the ventricular surface. Nonetheless the tanycytes appeared able to maintain a continuous, tight lining, as in controls, although some crystalloids were observed beneath the ventricular surface, either within tanycyte processes or within neuronal processes. Vinblastine treatment also resulted in the formation of identical crystalloids but at highest doses thoroughly destroyed the tanycyte lining of the median eminence and exposed cellular elements below the surface to the drug. Portal capillaries approaching the ventricular surface were generally free of any signs of drug response to either colchicine or vinblastine.     

Siderophore Production by Pathogenic Neisseria spp

Previous studies have established the importance of iron acquisition to the growth and virulence of Neisseria meningitidis and Neisseria gonorrhoeae. Although preliminary evidence that the Neisseria spp. produce siderophores has been presented, the exact mechanism of iron acquisition has remained obscure. Siderophore production by N. gonorrhoeae and N. meningitidis was induced in two different low-iron media. The iron-reactive siderophores, “gonobactin” and “meningobactin,” were partially purified by ion exchange chromatography followed by extraction with phenol-chloroform-ether or by gel filtration. The compounds were of low molecular weight, their synthesis was repressed by iron in the medium, and they appeared to be hydroxamic acids since they were stimulatory for Arthrobacter flavescens JG-9 (a hydroxamate auxotroph) and gave a positive Csáky reaction for bound hydroxylamine. In the iron form, the compounds had an absorption maximum of approximately 420 nm. Although meningobactin stimulated growth of the gonococcus in low-iron media and vice versa, the homologous activity was more marked, indicating that the compounds, though similar, were probably not identical. As determined by A. flavescens assay the meningococcus produced three to five times more siderophore than did the gonococcus; however, the amount of siderophore present in the culture fluids of even the meningococcus was 100- to 1,000-fold lower than the concentration of hydroxamate siderophores reported to be produced by Bacillus megaterium or Aerobacter aerogenes. Virulent, colony type 1 N. gonorrhoeae produced significantly more gonobactin than did the avirulent colony type 3 gonococci.     

Race and ethnic variation in college students’ allostatic regulation of racism-related stress

Racism-related stress is thought to contribute to widespread race/ethnic health inequities via negative emotion and allostatic stress process up-regulation. Although prior studies document race-related stress and health correlations, due to methodological and technical limitations, they have been unable to directly test the stress-reactivity hypothesis in situ. Guided by theories of constructed emotion and allostasis, we developed a protocol using wearable sensors and daily surveys that allowed us to operationalize and time-couple self-reported racism-related experiences, negative emotions, and an independent biosignal of emotional arousal. We used data from 100 diverse young adults at a predominantly White college campus to assess racism-related stress reactivity using electrodermal activity (EDA), a biosignal of sympathetic nervous system activity. We find that racism-related experiences predict both increased negative emotion risk and heightened EDA, consistent with the proposed allostatic model of health and disease. Specific patterns varied across race/ethnic groups. For example, discrimination and rumination were associated with negative emotion for African American students, but only interpersonal discrimination predicted increased arousal via EDA. The pattern of results was more general for Latinx students, for whom interpersonal discrimination, vicarious racism exposure, and rumination significantly modulated arousal. As with Latinx students, African students were particularly responsive to vicarious racism while 1.5 generation Black students were generally not responsive to racism-related experiences. Overall, these findings provide support for allostasis-based theories of mental and physical health via a naturalistic assessment of the emotional and sympathetic nervous system responding to real-life social experiences.

Racism in the United States shapes interracial social interactions (1) and, mirroring society-wide trends in the racialization of American politics (2, 3), the situation may be worsening with rising racial animosity (4, 5). Consequently, racism-related stress is hypothesized to contribute to widespread minority health disparities (6) and Black/White mortality differentials on a scale sufficient to influence election outcomes (7). One possible explanation for these disparities is that race-related stress increases negative emotions and physiological wear and tear via modulation of the sympathetic-adrenal-medullary (SAM) axis, hypothalamic-pituitary-adrenal (HPA) axis, and immune system (8). Up-regulation of these systems, often referred to generically as “the stress process,” is the outcome of the brain’s predictive modeling and regulation of the body’s energetic needs, or allostasis (9). Here, race-related stress is thought to increase energy demands as the brain prepares the body to deal with threats by marshaling oxygen, glucose, and other energetic mediators (10). Consequently, researchers have argued that ongoing allostatic up-regulation of the autonomic and endocrine systems, combined with immune activity modulation, in response to racism-related threats is physiologically taxing and over time increases vulnerability to chronic disease (11, 12). For example, downstream physiological adaptions to a body energized on high alert are thought to increase risks for excess adiposity, hypertension, diabetes, and cardiovascular disease (13–15), traditionally the leading cause of death in the United States.Despite the theoretical importance of regulatory allostatic processes for understanding racial health inequities, racism-related physiological responding has not been directly measured in real time in the real world. Conducting these assessments is challenging because the timing of many socially mediated experiences, such as racism-related incidents, occur in “social time”; that is, they are dependent upon actions beyond the control of the individual, are largely unobserved, and are highly variable and stochastic. Acute physiological changes are thus responses to temporally variable stimuli and are modulated on precise time scales in the order of seconds (i.e., SAM) and minutes (i.e., HPA). Although systematic and metaanalytic reviews find evidence that discriminatory experiences are correlated with mental and physical health both early (6) and later in life (16), most studies are cross-sectional, retrospective, and rely on behavioral and psychological self-reports, even when employing temporally sensitive methodologies (17). Although a few recent studies in natural settings incorporating biomarkers consistent with models of allostasis have begun filtering into the literature (18), their measurement strategies are not time-synchronized with race-related experiences. These studies provide post hoc evidence of allostatic process modulation, but do not measure allostatic regulation concurrently as it transpires in situ.Our study was designed to address these limitations and to directly test allostatic modulation of the sympathetic component of the SAM response to racism-related stress. To these ends, we developed a prospective protocol capturing events throughout the day, including the timing of racism-related experiences of perceived interpersonal discrimination, rumination on racism, and vicarious racism exposure, as well as negative emotions. Our design also included a wearable device that continuously tracked SAM activity using an electrodermal activity (EDA) sensor, a direct measure of the sympathetic nervous system (SNS) division of the autonomic nervous system that indexes affective arousal. This approach facilitated approximate time-synchronization of racism-related experiences with the SNS-mediated first-stage allostatic stress-response pathway. We were therefore able to operationalize two key aspects of stress-response dynamics temporally coupled with racism-related stressors: Negative emotion and SNS arousal. To our knowledge, this study provides a temporally coregistered and ecologically embedded assessment of the dynamic links between race-related stressors, negative emotions, and the SAM-mediated SNS component of a stress response among individuals of diverse ethnic backgrounds.     

Polymer Melting Kinetics Appears to be Driven by Heterogeneous Nucleation

A recently proposed method is used to parameterize the nucleation‐driven kinetics of poly(ε‐caprolactone) melting. The method is based on fitting a theoretically derived temperature dependence of the effective activation energy to the experimental dependence obtained from the Kissinger plot. Although the theoretical dependence fits the experimental one accurately, the fit gives rise to a surface free energy that is significantly smaller than the one obtained from crystallization data. A similar result is reported in other publications that make use of a homogeneous nucleation model for poly­mer melting. It is argued that a heterogeneous nucleation model is a more appropriate representation of the melting process and that its use resolves the problem of estimating the unusually small surface free energies.