Incidence and Risk Factors for Acid-fast Bacillus/Fungal Culture Positivity in Primary, Conversion, and Revision Hip and Knee Arthroplasty

INTRODUCTION

Previous literature has reported minimal incidences of positive fungal/AFB cultures, questioning the routine use of these tests. With growing concern for excessive use, predictive factors for patients at higher risk for intraoperative AFB/fungal infections would help surgeons limit unnecessary testing. This study evaluates the positivity rate and predictive factors of positive fungal and/or acid-fast bacillus (AFB) cultures after primary, conversion, or revision hip and knee arthroplasty.

METHOD

Two hundred thirty-eight knee and hip procedures were done between January 2007 and 2022 where intraoperative AFB/fungal cultures were obtained. Procedures included primary total knee arthroplasty, primary total hip arthroplasty, conversion, first of two-stage, second of two-stage, irrigation and débridement polyexchange, and aseptic revision. Positivity rates of intraoperative AFB/fungal cultures were calculated as binomial exact proportions with 95% confidence intervals and are displayed as percentages. Univariable generalized linear mixed models estimated the unadjusted effects of demographics, individual comorbid conditions, and procedural characteristics on the logit of positive AFB/fungal cultures.

RESULTS

Two hundred thirty-eight knee and hip procedures recorded an overall positivity rate of 5.8% for intraoperative AFB/fungal cultures. Aseptic revisions showed the lowest rates of positivity at 3.6%, while conversions showed the highest rates of positivity at 14.3%. The positivity rates are highest among patients who are male (9.0%), of Hispanic origin (12.0%), with body mass index <30 (6.4%), and a Charlson Comorbidity Index <5 (6.1%). History of a prior infection in the same surgical joint showed statistically significant influence of odds of culture positivity with an odds ratio of 3.47 (P-value: 0.039). Other demographic factors that we investigated including age, sex, race, ethnicity, body mass index, and Charlson Comorbidity Index did not show any notable influence on AFB/fungal positivity rates.

CONCLUSION

These results suggest utility in obtaining routine intraoperative AFB/fungal cultures, given the relatively high positivity and poor predictive factors.

The association of comorbid depression with mortality and amputation risk in patients with chronic limb-threatening ischemia

OBJECTIVE

There is increasing evidence that depression is a risk factor for worse outcomes in patients with peripheral artery disease. The association of depression in patients with chronic limb-threatening ischemia (CLTI) is not well described, nor is the impact of medical treatment for depression in this patient population. The objective of this study was to investigate the prevalence of depression in patients with CLTI, its association on major amputation and all-cause mortality, and whether medical antidepressant treatment is associated with improvement in these outcomes in patients with depression.

METHODS

A retrospective review of all adult patients (≥18 years old) diagnosed with CLTI from January 1, 2007, to December 31, 2018, at a single academic medical center was performed. Collected data included patient demographics, comorbidities, and diagnosis of depression within 6 months of initial CLTI diagnosis. We also collected data on use of antidepressant medications. Outcomes evaluated were need for major lower extremity amputation and all-cause mortality. Multivariable logistic regression models estimated the adjusted effects of comorbid depression and antidepressant medication use on major amputation and all-cause mortality. Kaplan-Meier survival curves illustrated the probabilities of survival and limb salvage over time, stratified by diagnosis of comorbid depression. Multivariable Cox proportional hazards models estimated the adjusted effects of comorbid depression on time to major amputation and all-cause mortality, and the adjusted effect of antidepressant treatment on time to all-cause mortality.

RESULTS

A total of 2987 patients with CLTI were identified. Mean age was 68.6 years (standard deviation, 12.9 years); 56.5% were male, and 43.5% were female. Comorbid depression within 6 months of CLTI diagnosis was present in 7.1% of the cohort (212 patients). In multivariable analysis, comorbid depression was associated with a 68% increase in the odds of major amputation (adjusted odds ratio [aOR], 1.68; 95% confidence interval [CI], 1.19-2.37; P < .01), a 164% increase in the odds of all-cause mortality among patients not taking antidepressants (aOR, 2.64; 95% CI, 1.31-5.32; P = .03), and only a 6% increase in the odds of all-cause mortality among patients taking antidepressants (aOR, 1.06; 95% CI, 0.72-1.55; P = .99). The effect of comorbid depression on mortality varied significantly by whether or not the patient was taking an antidepressant medication (P = .02).

CONCLUSIONS

Comorbid depression in the patient population with CLTI is associated with a worse prognosis for major lower extremity amputation overall, and a worse prognosis for all-cause mortality among patients not taking an antidepressant. Furthermore, antidepressant treatment in the presence of comorbid depression in this patient population is associated with an improvement in the odds of all-cause mortality, illustrating the potential importance of medical management of depression.

The impact of modern airport security protocols on patients with total shoulder replacements

BACKGROUND

Advancements in airport screening measures in response to 9/11 have resulted in increased false alarm rates for patients with orthopedic and metal implants. With the implementation of millimeter-wave scanning technology, it is important to assess the changes in airport screening experiences of patients who underwent total shoulder arthroplasty (TSA).

METHODS

Here, 197 patients with prior anatomic and reverse TSA completed between 2013 and 2020 responded to a questionnaire regarding their experiences with airport travel screening after their operation. Of these patients, 86 (44%) stated that they had traveled by plane, while 111 (56%) had not. The questionnaire addressed several measures including the number of domestic and international flights following the operation, number of false alarm screenings by the millimeter-wave scanner, patient body habitus, and presence of additional metal implants.

RESULTS

A total of 53 patients (62%) responded "yes" to false screening alarms due to shoulder arthroplasty. The odds of a false screening alarm for patients with other metal implants was 5.87 times that of a false screening alarm for patients with no other metal implants (P<0.1). Of a reported 662 flights, 303 (45.8%) resulted in false screening alarms. Greater body mass index was not significantly lower in patients who experienced false screening alarms (P=0.30).

CONCLUSIONS

Patients with anatomic and reverse TSA trigger false alarms with millimeter-wave scanners during airport screening at rates consistent with prior reports following 9/11. Patient education on the possibility of false alarms during airport screening is important until improvements in implant identification are made. Level of evidence: IV.

Long-term changes of Th17 and regulatory T cells in peripheral blood of dogs with spinal cord injury after intervertebral disc herniation

BACKGROUND

Intervertebral disc herniation (IVDH) is one of the most common causes of spinal cord injury (SCI) in dogs. As a result of acute SCI, a complex inflammatory response occurs in the spinal cord. Th17 cells (Th17) produce pro-inflammatory cytokines, while regulatory T cells (Treg) have opposite effects producing anti-inflammatory cytokines. Therefore, the aim of this study was to determine whether Th17- and Treg cells are involved in the pathogenesis of SCI or whether cellular changes occur due to coexisting inflammatory diseases. We hypothesized that chronic alterations in the Th17/Treg ratio are associated with a worse outcome after SCI.

METHODS

Twenty-six paretic or plegic dogs with IVDH with and without coexisting inflammatory disease were investigated in the acute stage of the disease and after recovery of SCI. In addition, a healthy control group was included (n = 14). Quantification of Th17 and Treg cells, from peripheral blood samples, was performed by multicolor flow cytometry and IL17 was measured using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

After recovery significantly higher levels of Th17 (p = 0.0265) and Treg cells (p = 0.00025) were detected compared to acute IVDH but Th17/Treg ratio did not differ significantly. Recovered dogs and the control group did not differ significantly from each other. No association between an imbalance in the ratio and neurologic severity or underlying inflammatory diseases was found.

CONCLUSION

This study demonstrated that altered Th17 and Treg levels in peripheral blood are altered in the acute stage of IVDH, preexisting inflammatory diseases seem not to influence these cell populations. Th17 and Treg cells could be considered when evaluating new treatment strategies for SCI.

Treatment of Vancouver B2 Femur Fractures With Open Reduction Internal Fixation Versus Revision Arthroplasty

Background Vancouver B2 periprosthetic femur fractures have traditionally been treated with revision arthroplasty. However, there is increasing evidence that open reduction and internal fixation (ORIF) may be a valid alternative treatment strategy. The purpose of this study was to compare the outcomes of ORIF versus revision arthroplasty for the treatment of Vancouver B2 fractures and evaluate the influence of the treating surgeon's fellowship training on treatment selection. Methodology This was a retrospective cohort study of 31 patients treated for Vancouver B2 periprosthetic fractures (16 ORIF and 15 revision arthroplasty) at a single academic Level 1 trauma center. Outcome measures included one-year mortality, revision, reoperation, infection, and blood loss. Results There were no statistically significant differences in revision, reoperation, or infection at an average follow-up of 65 weeks. Median estimated blood loss was higher in the arthroplasty group (700 cc versus 400 cc; P = 0.04). There were five deaths in the ORIF group versus one in the revision group (P = 0.18). Cases treated by surgeons with fellowship training in arthroplasty were more likely to be treated with revision arthroplasty (10/11, 90.9%) than those treated by surgeons with fellowship training in trauma (5/15, 33.3%; P < 0.01). Conclusions There was no difference in outcomes between the two treatment strategies, but revision was associated with higher blood loss. The appropriate treatment method should be based on surgeon familiarity and patients' characteristics.

Development of Radiographic Radiation Pneumonitis (RP) in Non-small Cell Lung Cancer Patients Treated With Stereotactic Body Radiation Therapy (SBRT) May Be Protective Against Further Disease Progression

Objectives: Radiation pneumonitis (RP) is a local inflammatory response, and we hypothesize that RP serves as an immune stimulator and is a protective factor against disease progression. 

Methods: We analyzed patients with early-stage non-small cell lung cancer (NSCLC) treated with stereotactic body radiation therapy (SBRT) at two institutions. Radiographic RP (RRP) was evaluated and maximal axial dimensions were measured at three-, six-, and twelve-month timepoints with surveillance CT. RRP was measured using radiographic markers such as ground-glass opacities and airspace consolidation. Disease recurrence was evaluated and categorized as local, regional, and distant. 

Results: Seventy-seven unique patient records were randomly selected from the database, 72 patients (93.5%) had RRP and five patients (6.5%) did not. The median follow-up was 24.3 months (IQR: 12.0 - 41.9). Disease failure occurred in 28.6% of patients with 6.5% local only, 2.6% regional only, 7.8% distant only, and 11.7% with multiple recurrences. Patients with RRP demonstrated a lower rate of disease failure with 25.0% of those with RRP experiencing disease failure and 80% of those without RRP experiencing disease failure (p=0.02). Patients with RRP had a 71% reduced risk of disease recurrence, compared to patients with no RRP, after adjusting for maximum tumor dimension (HR 0.29, p = 0.05). Among patients with RRP, there was no significant difference in recurrence based on extent of RRP (maximal area of RRP on CT). RRP did not correlate with overall survival. 

Discussion: Most patients who received SBRT had RRP, and this study suggests that it may be protective of cancer recurrence. These results are hypothesis-generating and will need to be validated in larger and independent datasets. 

Evaluation of the Cost Effectiveness of Routine Histopathologic Femoral Head Analysis in Hip Arthroplasty

Purpose

Histopathologic analysis of femoral head specimens following total hip arthroplasty (THA) is a routine practice that represents a significant use of health care resources. However, it occasionally results in discovery of undiagnosed hematopoietic malignancy and other discrepant diagnoses such as avascular necrosis. The purpose of this study was to determine the rate of discordant and discrepant diagnoses discovered from routine histopathological evaluation of femoral heads following THA and perform a cost analysis of this practice.

Materials and Methods

A review of patients undergoing primary THA between 2004-2017 was conducted. A comparison of the surgeon’s preoperative and postoperative diagnosis, and the histopathologic diagnosis was performed. In cases where the clinical and histopathology differed, a review determined whether this resulted in a change in clinical management. Medicare reimbursement and previously published cost data corrected for inflation were utilized for cost calculations.

Results

A review of 2,134 procedures was performed. The pathologic diagnosis matched the postoperative diagnosis in 96.0% of cases. Eighty-three cases (4.0%) had a discrepant diagnosis where treatment was not substantially altered. There was one case of discordant diagnosis where lymphoma was diagnosed and subsequently treated. The cost per discrepant diagnosis was $141,880 and per discordant diagnosis was $1,669 when using 100% Medicare reimbursement and Current Procedural Terminology (CPT) code combination 88304+88311.

Conclusion

Histopathologic analysis of femoral head specimens in THAs showed an association with high costs given the rarity of discordant diagnoses. Routine use of the practice should be at the discretion of individual hospitals with consideration for cost and utility thresholds.

Medical Supervision of Illinois Public and Private High School Athletics

BACKGROUND

High-school sports participation in the United States has increased over the years with a corresponding increase in the number of injuries. Leading medical and sports organizations nationwide advocate for an increase in proper medical supervision of athletes.

OBJECTIVES

To analyze athletic medical coverage in Illinois high schools and compare differences between public and private Illinois high school.

METHODS

A survey addressing various components of sports medical coverage was distributed in 2018 to all 810 Illinois High School Association (IHSA) high schools to be completed electronically.

RESULTS

The response rate was 50% (407/810 schools). Of the responding schools, 14% were private high schools and 86% public high schools. An orthopedic surgeon, family doctor, pediatrician, or another type of physician were present on sidelines in 9.2% of private high schools and 8.5% of public high schools. Athletic trainers (ATs) were present on sidelines in 91% of private high schools and in 79% of public high schools. There was 68% of private high schools reporting coaches trained in CPR versus 85% in public high schools. Both private and public high schools had high rates of having written emergency action plans (89% vs 91%), AED on site (100% vs 99%), written concussion management protocols (96% vs 97%).

CONCLUSION

Our study found similar rates of high school medical coverage as compared to national studies, with some significant differences found between private and public high schools. Most Illinois high schools had high rates of having written EAPs, concussion management protocols and AEDs on site. Overall, an increase of medical supervision and emergency preparedness is needed, which should come in the form of increasing AT and physician presence alongside community and school engagement for improved implementation of coverage.

Crying with a Patient: A Pilot Study of the Attitudes of Physicians and Physicians-in-Training

Physicians are taught to maintain emotional distance. However, limited research suggests that many have cried in the hospital setting. How physicians understand and manage their emotions is an understudied topic, and public displays of emotion are not adequately addressed in medical education. To better understand physician and trainee views about displaying emotion in front of patients, we conducted a mixed-methods study using vignettes, closed-, and open-ended questions to explore the current attitudes of medical students, residents, and physicians at one academic medical center regarding whether or not it is appropriate for a physician to cry with a patient. Quantitative analyses investigated the effects that vignette constructs, level of training, gender, and history of crying at work within the last six months had on respondents' opinions regarding the appropriateness of physicians crying. An open-ended question, "Describe a situation in the hospital during which you felt like crying," was analyzed for key themes.

Epidemiology and Clinical Outcomes of Microscopic Colitis: Preliminary Results From the Loyola University Microscopic Colitis Registry (LUMiCoR)

Microscopic colitis (MC) is a common cause of chronic diarrhea with limited long-term data. We searched the pathology records at our institution from 2008 to 2018 to identify cases of MC. Total sample included patients with either a diagnosis of MC or incomplete MC (MCi).Chart review was performed and data were summarized for descriptive statistics. Logistic regression was used to estimate the unadjusted effects of predictors on MC. A total of 216 patients (88.32% white, 80.56% females, mean age 67.12 +/– 15.79) were studied; 50.00% had CC, 40.28% had LC and 9.72% had MCi. Majority (52.31%) were smokers and 21.84% of females were using some form of hormonal therapy. The odds of LC in reference to CC were significantly higher for those using tricyclic antidepressants (TCAs) (OR: 3.23, 95% C.I: 1.18–8.80, p = 0.02). The odds of smoking, statins, aspirin and beta-blocker use were decreased in MCi in reference to CC (all p < 0.05), 29 (74.35%) patients with unresolved symptoms underwent repeat colonoscopies with biopsies. One case of MCi resolved, 8 (72.73%) out of 11 cases of LC resolved, 2 (18.18%) continued to be LC and 1 (9.09%) transformed to CC, 8 (47.06%) out of 17 cases of CC resolved, 8 (47.06%) continued to be CC and 1 (5.88%) transformed to LC. Majority of patients had CC. TCA use resulted in increased odds of LC in reference to CC. Biopsies from repeat colonoscopies in some patients revealed changes in the pathological diagnoses raising the question of interchangeability of MC (CC to LC and vice versa).

Impact of Race and Health Insurance Status on Response to Neoadjuvant Chemotherapy for Breast Cancer Patients

We evaluated how race, insurance status, and other sociodemographic, tumor, and treatment variables influenced the response to neoadjuvant chemotherapy (NAC) in breast cancer. We performed an IRB-approved retrospective review of 298 breast cancer patients treated with NAC from 2006-2018 at our institution. Univariable and multivariable binary logistic regression analyses were performed to estimate the effects of race, insurance status, and other variables on outcomes. Outcomes of interest included pathologic complete response (pCR), partial response (pPR), and any response (pCR or pPR). Sixty-nine patients (23%) identified as African American. One hundred sixty-eight (57%) patients had private insurance, 71 (24%) had Medicare, 40 (14%) had Medicaid, and 17 (6%) had no insurance. Insurance status was a predictor for any clinical response to NAC in both univariable and multivariable analyses (p<0.01), where odds of pCR or pPR were lower for patients with Medicare compared to private insurance (OR 0.32, 95% CI: 0.15-0.70, p<0.01). Other variables significant for the response to NAC included body mass index, hormone receptor status, clinical group stage, and Ki-67. Race did not influence the response to NAC. Insurance provider, body mass index, hormone receptor status, clinical group stage, and Ki-67 may be useful predictors of treatment outcomes. Future studies that assess the impacts of insurance status and other identified factors on treatment response may help evaluate outcomes in at-risk populations with factors that preclude full benefit from NAC.

Risk of Complications With the Total Contact Cast in Diabetic Foot Disorders

The custom-fabricated total contact cast is commonly used in the treatment of diabetic foot disorders. This resource-consuming treatment option has been associated with iatrogenic morbidity as well as the need for urgent cast removal and inspection of the underlying limb when potential problems arise. Over a 10-year period, 381 diabetic patients had 2265 total contact cast applications by certified orthopaedic technologists, in a university orthopaedic practice, under the supervision of university faculty. Patients were stratified by glycemic control based on hemoglobin A1c levels, and obesity based on body mass index (BMI). Complications were grouped as (1) development of a new ulcer or wound, (2) new or increasing odor or drainage, (3) wound infection, (4) gangrene, (5) newly identified osteomyelitis, and (6) pain or discomfort necessitating cast change or removal. At least 1 complication was observed in 159 of 381 patients. The odds of experiencing a cast-related event for patients with a BMI greater than 30 kg/m² was 1.55 times greater than patients with a BMI less than 25 kg/m². As compared to patients with good glycemic control, the odds of experiencing a cast-associated complication was 1.27 times greater in patients with moderate glycemic control and 1.48 times greater in patients with poor glycemic control. The total contact cast is commonly used in the treatment of diabetic foot morbidity. Treatment-associated morbidity may well be greater than previously appreciated. Complications are more likely in patients who have poor glycemic control and are morbidly obese. This information will hopefully stimulate interest in developing commercially available nonrigid alternatives that retain the attributes of the resource-consuming rigid device, with the potential advantage of avoiding the associated morbidity.Levels of Evidence: Level IV, retrospective chart review.

GRP78 expression and clinical outcomes in pancreatic cancer: A single institution review

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Background: Pancreatic Ductal Adenocarcinoma (PDAC) has one of the lowest 5-year survival rates of all cancers. Poor prognosis can be attributed in part to late detection and chemoresistance. Perioperative chemotherapy with or without radiation is the standard treatment for resectable PDAC, however recurrence rates remain high. GRP78 (HSPA5/BiP) is an endoplasmic reticulum (ER) chaperone protein involved in regulation of the ER stress response that leads to pro-survival pathway activation and chemoresistance in tumor cells. Prior studies of suppression of GRP78 expression in PDAC cell lines led to increased pancreatic cell apoptosis in response to gemcitabine. In vivo studies of human PDAC xenografts showed that tumors with higher GRP78 expression were associated with increased chemoresistance. Methods: We conducted a single institution retrospective review of 53 patients who underwent resection of PDAC from 1/1/2009-7/1/2016. Archived tumor tissue expression of GRP78 was assessed by immunohistochemistry (IHC) and scored as 0-3+. GRP78 IHC scores of 0-1+ were categorized as low and scores of 2-3+ as high. Corresponding clinical data were collected. Adjusted effects of GRP78 expression on the hazard of treatment failure or death were estimated using Cox proportional hazards models. Type III Wald Chi-square p-values are reported for the overall effect in each model. Results: GRP78 expression level demonstrated a significant effect on disease free survival (DFS) in unadjusted analyses (HR 2.00, p = 0.05), as well as after adjusting for performance status (p = 0.03), initial overall stage (p = 0.05), pathological tumor stage (p = 0.02), pathological node stage (p < 0.01), resection margins (p = 0.05), and neoadjuvant therapy (p = 0.05) in separate models. In unadjusted analysis, high GRP78 expression showed a trend towards worsened overall survival (OS), but did not reach statistical significance (HR 1.8, p = 0.11). The effect on OS was significant when adjusting for pathological tumor stage (p = 0.04) and pathological node stage (p = 0.01). (575). Conclusions: Consistent with prior animal studies, our retrospective review revealed that high GRP78 expression was associated with worsened DFS in patients with resectable PDAC. When adjusting for pathological staging, high GRP78 expression had a similar impact on OS. These findings warrant further evaluation of the role of GRP78 in prognosis, response to therapy and as a potential treatment target.

Immunological and clinical profiles of patients with advanced or metastatic melanoma receiving immune checkpoint inhibitors to investigate potential biomarkers for immune-related adverse events

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Background: Immune-related adverse events (irAEs) related to immune checkpoint inhibitors (ICIs) may target any organ and originate from autoreactive T cells injuring host tissues. There is a need to develop prognostic and predictive biomarkers to distinguish patients (pts) who will benefit from ICIs avoiding irAEs during treatment. We propose that irAEs are the result of many biological variables. We hypothesize that within each pts complex immunological profile, there may be patterns and associations which exist that represent a state of inflammation that is present prior to ICI therapy and hypothesize this could predict irAEs development. Methods: We created individual immunological profiles of 11 pts diagnosed with MM prior to receiving ICIs. Assays included: PBMC composition, circulating chemokines/cytokines, and IκB degradation status. CD4 and CD8 T cells were studied for their phenotype, activation status, proliferative capacity and cytolytic granules. Clinical data was collected on a larger MM pt cohort (n = 41) and descriptive statistics were utilized to characterize reported irAEs . Results: 110 input markers were utilized for immune signature analysis. 6 of the 11 pts reported grade 2+ irAEs after ICI therapy. The pro-inflammatory CCL13, CCL1, FLT-3, IL12p40, TRAIL, and granzyme b expressing CD4 T cells at steady state and after CD3 activation were significantly higher in pts with irAEs. Known inflammatory suspects (i.e., IL-2, IL-15, TNF-a or % CD8 T cells) were not associated with irAE development . A rank correlation test showed significant associations between the levels of these factors. irAEs were reported in 41% (n = 17) for our larger cohort, most frequently skin rash (7%), colitis (7%), hepatitis (7%) and thyroid dysfunction (4%). Conclusions: The immune signatures of pts with irAEs are highly heterogeneous and possess distinctive immunological patterns. Our results introduce possible molecular mechanisms that may aid understanding of irAE development, perhaps providing the basis for a new model prospectively testing these markers to risk stratify pts receiving ICIs.

Seasonal Variations of Mercury Levels in Selected Medicinal Plants Originating from Poland

The presence of mercury in the living cells may be caused by environmental pollution with this element, which is referred to as a toxic xenobiotic. Many literature reports have provided evidence for toxic effects of low levels of mercury in the human body. Therefore, it seems essential to investigate mercury content in food and in natural environment, particularly its seasonal variations. The objective of this study was to determine trace amounts of mercury in 45 samples of 20 medicinal plant species collected in northern Poland, in various seasons of the year, i.e., in autumn 2012 and then spring 2013. The results obtained showed that the levels of mercury in the herbs were lower in spring (3.66-34.89 ng/g) than in autumn (4.55-81.54 ng/g). The statistically significant correlation (p < 0.05) between the levels of mercury in herbs collected in spring and autumn indicates hazardous accumulation of the element in plants in autumn. The highest levels of mercury were found in leaves and plants growing in the vicinity of busy streets. Perennials plants have a significantly higher mercury levels as compared to those of monocarpic plants. Furthermore, commonly used herbal plants have a significantly higher mercury levels as compared to those less common.

Essential Elements and Their Relations to Phenolic Compounds in Infusions of Medicinal Plants Acquired from Different European Regions

The aim of this research was to compare chemical composition of herbs acquired from different European countries. The concentrations of P, Fe, Mn, Zn, Cu, phenolic compounds, and the antioxidant activity were determined in infusions of 27 medicinal herbs (7 species) from Lithuania, Serbia, Italy, and Portugal. Total and extractable P were expressed in milligrams per liter and metals in micrograms per liter and followed the sequence: Fe > Mn > Zn > Cu, while antioxidant activity ranged from 29.4 to 217.8 mg of Trolox equivalent (TE) per liter. Total flavonoids were in the range of 20.5-95.1 mg L(-1). The rank order of phenolic compounds assayed by HPLC method (in mg L(-1) of infusion) was as follows: rutin > myricetin > quercetin > kaempferol, and chlorogenic > ferulic > p-coumaric > caffeic > gallic acids. Significant correlations were found between total P-inorganic phosphate P, Zn-Mn, Mn-Cu, total flavonoids-antioxidant activity, and quercetin with caffeic and ferulic acids. Generally, medicinal plant infusions differed in their chemical composition, strongly depending on plant species, regardless of the origin from distant geographical areas of Europe. Principal component analysis selected the concentrations of Cu, Mn, total and inorganic phosphate P, as factors which strongly influence differentiation of the samples. Moreover, infusions from Hyperici herba and Helichrysi inflorescentia contained significant amounts of water-extractable Mn and Fe forms as claimed by the Dietary Reference Intakes for humans.

Complex and non-redundant signals from individual odor receptors that underlie chemotaxis behavior in Drosophila melanogaster larvae

The rules by which odor receptors encode odors and allow behavior are still largely unexplored. Although large data sets of electrophysiological responses of receptors to odors have been generated, few hypotheses have been tested with behavioral assays. We use a data set on odor responses of Drosophila larval odor receptors coupled with chemotaxis behavioral assays to examine rules of odor coding. Using mutants of odor receptors, we have found that odor receptors with similar electrophysiological responses to odors across concentrations play non-redundant roles in odor coding at specific odor concentrations. We have also found that high affinity receptors for odors determine behavioral response thresholds, but the rules for determining peak behavioral responses are more complex. While receptor mutants typically show loss of attraction to odors, some receptor mutants result in increased attraction at specific odor concentrations. The odor receptor mutants were rescued using transgenic expression of odor receptors, validating assignment of phenotypes to the alleles. Vapor pressures alone cannot fully explain behavior in our assay. Finally, some odors that did not elicit strong electrophysiological responses are associated with behavioral phenotypes upon examination of odor receptor mutants. This result is consistent with the role of sensory neurons in lateral inhibition via local interneurons in the antennal lobe. Taken together, our results suggest a complexity of odor coding rules even in a simple olfactory sensory system.

Two new double-stranded RNA molecules showing non-mendelian inheritance and heat inducibility in Saccharomyces cerevisiae

Certain strains of Saccharomyces cerevisiae were found to have a complex nuclear defect (designated clo-) that makes cells unable to maintain some L-B and some L-C double-stranded RNAs at 25 degrees C. The clo- strains were not defective in maintenance of L-A, M1, or M2 double-stranded RNAs. Most clo-strains lacking L and M carry small amounts of two double-stranded RNA species intermediate in size between L and M and denoted T (2.7 kilobase pairs) and W (2.25 kilobase pairs). Some strains carry both T and W, some carry neither, and some carry only W; no strains carrying only T have been found. Both T and W show 4+:0 segregation in meiosis and efficient transmission by cytoplasmic mixing (cytoduction), indicating that they are non-Mendelian genetic elements. T and W do not cross-hybridize with each other or with L-A, L-B, L-C, M1, M2, or chromosomal DNA. T and W are apparently distinct from other known non-Mendelian genetic elements (2mu DNA, [rho], [psi], 20S RNA, [URE3]). In most strains the copy number of both T and W is increased about 10-fold by the growth of cells at 37 degrees C. This heat inducibility of T and W is under control of a cytoplasmic gene. T and W double-stranded RNAs are not found in a purified L-containing virus-like particle preparation from a strain containing L-B, T, and W double-stranded RNAs. The role, if any, of T or W in the killer systems is not known.

Characterization and biosynthesis of soluble and membrane-bound carbonic anhydrase in brain

Carbonic anhydrase from both the cytoplasmic and membrane fractions of the forebrains of rats was characterized with respect to enzymatic activity, immunoreactivity, and in vitro biosynthesis. A procedure for the rapid purification of both membrane-bound and soluble brain carbonic anhydrase is presented that permits retention of full enzymatic activity. Both forms of the enzyme were found to show specific activities of approximately 5500 Units/mg protein when CO2 hydrating activity was determined. In addition, they exhibited similar esterase activity when assayed with p-nitrophenyl acetate. The membrane-bound form, although requiring detergent for extraction from membranes, was freely soluble in aqueous buffers after purification. The molecular weights of both soluble and membrane-bound carbonic anhydrase are 30,000 daltons, and mixing experiments failed to show any significant differences with respect to size. The two forms also exhibit isoelectric points of 7.2. However, the two proteins were found to differ in two respects. Complement fixation indicated that antibodies to soluble carbonic anhydrase had a higher affinity for the soluble form than for the membrane-bound form. The failure to observe any precursor-product relationship between these two proteins with pulse chase studies and the establishment that carbonic anhydrase-like proteins are synthesized on both free polysomes and the rough endoplasmic reticulum indicated that these proteins are synthesized by two separate mechanisms. In vitro synthesis on both free and bound polysomes was determined by two independent methods using different antibodies and different analytical procedures. The basis for these findings and their physiologic importance are discussed.

Transformation of Kluyveromyces lactis by killer plasmid DNA

Some strains of Kluyveromyces lactis contain two linear double-stranded DNA plasmids, k1 and k2. The presence of the two plasmids confer on the cell a "killer" character, due to the production of a toxin that kills the sensitive cells. We have used one of these linear DNA molecules as a gene vector to transform K. lactis cells. Hybrid plasmids containing parts of the k1 plasmid and the URA3 gene of Saccharomyces cerevisiae have been constructed. We have found that the hybrid plasmids were able to transform a uracil-requiring strain of K. lactis (uraA mutant) to a prototrophic form. The transformed phenotype cosegregated with the hybrid plasmids. The transforming plasmids contained the sequence of one or both ends of the linear k1 DNA, but they were integrated into a circular molecule.

Role of nuclear genes in expression of a mitochondrial tRNA gene in Saccharomyces cerevisiae

In yeast mitochondria, most of the isoaccepting species of tyrosyl tRNA are coded by a mitochondrial gene, tyrA. A particular isoaccepting species is coded by a second mitochondrial gene, tyrB. This gene is not expressed in certain strains of yeast which show no deficient phenotype. Genetic crosses between strains expressing or not expressing the tyrB gene demonstrate that expression is controlled by specific nuclear genes and that a mutation of the tyrA gene can be bypassed when the tyrB gene is operative.

Linear mitochondrial deoxyribonucleic acid from the yeast Hansenula mrakii

The mitochondrial deoxyribonucleic acid (mtDNA) from a petite-negative yeast, Hansenula mrakii, was studied. A linear restriction map was constructed with 11 restriction enzymes. The linearity of the genome was confirmed by direct end labeling of the molecule, followed by restriction analysis. The molecular weight of the DNA was found to be 55,000 base pairs. This is the first linear mtDNA found in yeast species. Using specific gene probes obtained from Saccharomyces cerevisiae mtDNA, we have constructed a gene map of H. mrakii mtDNA. The arrangement of genes in this linear genome was very different from the circular mtDNA of other known yeasts.

Two isoaccepting seryl tRNAs coded by separate mitochondrial genes in yeast

In S. cerevisiae four isoacceptor mitochondrial tRNAs for serine have been separated by reversed phase chromatography. At least two of these species are products of different genes. In this work the deletion mapping technique has been used to locate two genes for tRNAser. The gene for tRNAser previously localized in the oli I region of the mitochondrial genome has been found to code for tRNAser2, and another gene coding for tRNAser1 has been detected in the region where most of other tRNA genes are found. Results of fine mapping experiments allowed to localize this gene in the proximity of the gene for tRNAarg.

The genetic map of transfer RNA genes of yeast mitochondria: correction and extension

Ninety five rho- mitochondrial DNA's of Saccharomyces cerevisiae were compared for their deletion structure by means of 15 genetic markers and 22 tRNA genes. The patterns of co-deletion and co-retention of different tRNA genes allowed us to determine their positions with respect to each other. The deduced order of tRNA genes was consistent with the order of the genetic markers established by independent genetic approaches. Our previously proposed mitochondrial tRNA gene map has been revised and extended. Transfer RNA genes, corresponding to all 20 aminoacids, and two isoacceptor tRNA genes were localized. The possible position of each tRNA gene has been indicated on the physical map of mitochondrial DNA. Seventeen tRNA genes are carried by a narrow region representing less than 20% of the wild type genome.

Preferential deletion of a specific region of mitochondrial DNA in Saccharomyces cerevisiae by ethidium bromide and 3-carbethoxy-psoralen: directional retention of DNA sequence

Grande strains of Saccharomyces cerevisiae were mutagenized either by ethidium bromide or by 3-carbethoxy-psoralen (a monofunctional furocoumarin derivative) activated by 365nm light. 973 primary rho- clones induced were randomly collected and analyzed individually for the presence or absence of fifteen mitochondrial genetic markers. 1. Under mild conditions of mutagenesis, 83% of the primary clones showed single-deletion genotypes; a unique order of 14 markers could be deduced from the patterns of the deletion. The gene order confirmed our previous map constructed from the analysis of established non-random petite clones. From the frequencies of disjunction between markers, the distance separating 14 mitochondrial markers were estimated. 2. One region, carrying oxi-3, pho-1 and mit 175 loci, was preferentially lost in rho- mutants: there is a strong constraint in the frequencies of various genotypes found in rho- clones. On each side of this particular region, a bidirectionally oriented pattern of retention of markers is observed.