Bleeding Risk With Combination Intrapleural Fibrinolytic and Enzyme Therapy in Pleural Infection: An International, Multicenter, Retrospective Cohort Study

BACKGROUND

Combination intrapleural fibrinolytic and enzyme therapy (IET) has been established as a therapeutic option in pleural infection. Despite demonstrated efficacy, studies specifically designed and adequately powered to address complications are sparse. The safety profile, the effects of concurrent therapeutic anticoagulation, and the nature and extent of nonbleeding complications remain poorly defined.

RESEARCH QUESTION

What is the bleeding complication risk associated with IET use in pleural infection?

STUDY DESIGN AND METHODS

This was a multicenter, retrospective observational study conducted in 24 centers across the United States and the United Kingdom. Protocolized data collection for 1,851 patients treated with at least one dose of combination IET for pleural infection between January 2012 and May 2019 was undertaken. The primary outcome was the overall incidence of pleural bleeding defined using pre hoc criteria.

RESULTS

Overall, pleural bleeding occurred in 76 of 1,833 patients (4.1%; 95% CI, 3.0%-5.0%). Using a half-dose regimen (tissue plasminogen activator, 5 mg) did not change this risk significantly (6/172 [3.5%]; P = .68). Therapeutic anticoagulation alongside IET was associated with increased bleeding rates (19/197 [9.6%]) compared with temporarily withholding anticoagulation before administration of IET (3/118 [2.6%]; P = .017). As well as systemic anticoagulation, increasing RAPID score, elevated serum urea, and platelets of < 100 × 10⁹/L were associated with a significant increase in bleeding risk. However, only RAPID score and use of systemic anticoagulation were independently predictive. Apart from pain, non-bleeding complications were rare.

INTERPRETATION

IET use in pleural infection confers a low overall bleeding risk. Increased rates of pleural bleeding are associated with concurrent use of anticoagulation but can be mitigated by withholding anticoagulation before IET. Concomitant administration of IET and therapeutic anticoagulation should be avoided. Parameters related to higher IET-related bleeding have been identified that may lead to altered risk thresholds for treatment.

Factors Associated with Nonsuppression of HIV Infection in the Spanish VACH Cohort

We aim to determine the prevalence of HIV nonsuppression and factors associated with it. This is a cross-sectional multicenter study carried out in January 2016 with data of the VACH Cohort, a registry participated by 23 hospitals from most regions of Spain. The prevalence of HIV nonsuppression, defined as HIV RNA ≥200 copies/mL, is documented. The possible association of HIV nonsuppression with sociodemographic and clinical variables is assessed with a logistic regression analysis. A total of 30,843 adult patients are included; 7,358 of them (23.86%) have nonsuppressed HIV. An association is found between nonsuppression of HIV and the following variables: lower body mass index, lower age of patients in their last registered visit, lower number of visits carried out during follow-up, lower last available CD4 cell count, higher age of patients at the time of their HIV infection diagnosis, higher lowest available CD4 cell count, higher highest available HIV RNA, enrolment in the Cohort in first years of the HIV epidemic, region of Spain where the patient is attended other than Andalusia, HIV risk factor other than sexual, occurrence of death during follow-up, hepatitis C coinfection, being a smoker, pertaining to groups A1 or A2 of the CDC groups classification, and not taking antiretroviral treatment, p < .001 in all cases. HIV nonsuppression is still common with the effective antiretroviral treatment nowadays available. HIV nonsuppression is associated with HIV risk factor other than sexual, hepatitis C coinfection, and being a smoker, among other factors.

Microbiome profile associated with malignant pleural effusion

Introduction

There is ongoing research into the development of novel molecular markers that may complement fluid cytology malignant pleural effusion (MPE) diagnosis. In this exploratory pilot study, we hypothesized that there are distinct differences in the pleural fluid microbiome profile of malignant and non-malignant pleural diseases.

Method

From a prospectively enrolled pleural fluid biorepository, samples of MPE were included. Non-MPE effusion were included as comparators. 16S rRNA gene V4 region amplicon sequencing was performed. Exact Sequence Variants (ESVs) were used for diversity analyses. The Shannon and Richness indices of alpha diversity and UniFrac beta diversity measures were tested for significance using permutational multivariate analysis of variance. Analyses of Composition of Microbiome was used to identify differentially abundant bacterial ESVs between the groups controlled for multiple hypothesis testing.

Results

38 patients with MPE and 9 with non-MPE were included. A subgroup of patients with metastatic adenocarcinoma histology were identified among MPE group (adenocarcinoma of lung origin (LA-MPE) = 11, breast origin (BA-MPE) = 11). MPE presented with significantly greater alpha diversity compared to non-MPE group. Within the MPE group, BA-MPE was more diverse compared to LA-MPE group. In multivariable analysis, ESVs belonging to family S24-7 and genera Allobaculum, Stenotrophomonas, and Epulopiscium were significantly enriched in the malignant group compared to the non-malignant group.

Conclusion

Our results are the first to demonstrate a microbiome signature according to MPE and non-MPE. The role of microbiome in pleural effusion pathogenesis needs further exploration.

Epidemiology and management of bacterial leaf spot on watermelon caused by Pseudomonas syringae

Bacterial leaf spot of watermelon caused by Pseudomonas syringae has been an emerging disease in the southeastern United States in recent years. Disease outbreaks in Florida were widespread from 2013 to 2014 and resulted in foliar blighting at the early stages of the crop and transplant losses. We conducted a series of field trials at two locations over the course of two years to examine the chemical control options that may be effective in management of this disease, and to investigate the environmental conditions conducive for bacterial leaf spot development. Weekly applications of acibenzolar-S-methyl (ASM) foliar, ASM drip, or copper hydroxide mixed with ethylene bis-dithiocarbamate were effective in reducing the standardized area under the disease progress curve (P < 0.05). Pearson's correlation test demonstrated a negative relationship between the average weekly temperature and disease severity (-0.77, P = 0.0002). When incorporated into a multiple regression model with the square root transformed average weekly rainfall, these two variables accounted for 71% of the variability observed in the weekly disease severity (P < 0.0001). This information should be considered when choosing the planting date for watermelon seedlings as the cool conditions often encountered early in the spring season are conducive for bacterial leaf spot development.

Sperm Release From the Oviductal Epithelium Depends on Ca(2+) Influx Upon Activation of CB1 and TRPV1 by Anandamide

The oviduct acts as a functional sperm reservoir in many mammalian species. Both binding and release of spermatozoa from the oviductal epithelium are mainly modulated by sperm capacitation. Several molecules from oviductal fluid are involved in the regulation of sperm function. Anandamide is a lipid mediator involved in reproductive physiology. Previously, we demonstrated that anandamide, through activation of the cannabinoid receptor type 1 (CB1), promotes sperm release from bovine oviductal epithelial cells, and through CB1 and the transient receptor potential vanilloid 1 (TRPV1), induces sperm capacitation. Herein we investigate co-activation between CB1 and TRPV1, and Ca(2+) influx as part of the mechanism of action of anandamide during sperm release from oviductal cells. Our results indicate that in the absence of Ca(2+) anandamide failed to release spermatozoa from oviductal epithelial cells. Additionally, sperm release promoted by cannabinoid and vanilloid agonists was abolished when the spermatozoa were preloaded with BAPTA-AM, a Ca(2+) chelator. We also determined Ca(2+) levels in spermatozoa preloaded with FURA2-AM co-cultured with oviductal cells and incubated with different cannabinoid and vanilloid agonists. The incubation with different agonists induced Ca(2+) influx, which was abolished by CB1 or TRPV1 antagonists. Our results also suggest that a phospholypase C (PLC) might mediate the activation of CB1 and TRPV1 in sperm release from the bovine oviduct. Therefore, our findings indicate that anandamide, through CB1 and TRPV1 activation, is involved in sperm release from the oviductal reservoir. An increase of sperm Ca(2+) levels and the PLC activation might be involved in anandamide signaling pathway.

Very low level viraemia and risk of virological failure in treated HIV-1-infected patients

OBJECTIVES

The aim of the study was to investigate whether very low level viraemia (VLLV) (20-50 HIV-1 RNA copies/mL) was associated with increased risk of virological failure (VF) as compared with persistent full suppression (< 20 copies/mL).

METHODS

From the VACH Cohort database, we selected those patients who started antiretroviral therapy (ART) after January 1997 and who achieved effective viral suppression [two consecutive viral loads (VLs) < 50 copies/mL] followed by full suppression (at least one VL <20 copies/mL). We carried out survival analyses to investigate whether the occurrence of VLLV rather than maintaining full suppression at < 20 copies/mL was associated with virological failure (two consecutive VLs > 200 copies/mL or one VL > 200 copies/mL followed by a change of ART regimen, administrative censoring or loss to follow-up), adjusted for nadir CD4 cell count, sex, age, ethnicity, transmission group, type of ART and time on effective suppression at < 50 copies/mL.

RESULTS

Of 21 480 patients who started ART, 13 674 (63.7%) achieved effective suppression at < 50 copies/mL, of whom 4289 (31.4%) further achieved full suppression at < 20 copies/mL after May 2009. A total of 2623 patients (61.1%) remained fully suppressed thereafter, while 1666 had one or more episodes of VL detection > 20 copies/mL (excluding virological failure). A total of 824 patients had VLLV after suppression at < 20 copies/mL. VLLV was not associated with virological failure as compared with persistent full suppression [hazard ratio (HR) 0.67; 95% confidence interval (CI) 0.44-1.00], independently of the number of blips recorded (from one to 18).

CONCLUSIONS

In our population of HIV-infected patients on ART who achieved viral suppression at < 20 copies/mL, the risk of virological failure was no different for patients who remained fully suppressed compared with those who experienced subsequent episodes of VLLV.

[Results after distraction arthroplasty according to Bufalini and Perugia in early stages of trapeziometacarpal osteoarthritis]

BACKGOUND

A distraction arthroplasty of the trapeziometacarpal joint was introduced by Bufalini and Perugia for the treatment of the early stages of carpometacarpal osteoarthritis. Our retrospective study presents the results of this technique. Thereby, a tendon graft anchored to the distal second metacarpal is fixed at the base of the first metacarpal, keeping it in distraction.

MATERIAL AND METHODS

10 distraction arthroplasties were performed in 9 patients with carpometacarpal osteoarthritis stage I and II of the thumb after unsuccessful conservative therapy. In 2 cases, which were excluded from our study, trapeziectomy had to be performed because of persisting pain. Patient satisfaction, pain measurement, range of motion, and tip, key and grip strength were evaluated at a follow-up of 46.5 (29-63) months in the remaining 7 patients (8 operations overall). Strengh measurement was taken in an absolute value and compared to the opposite side. Thumb range of motion was measured with the combined flexion-opposition of the thumb with the Kapandij index and also the angle of abduction of the metacarpal I to metacarpal II. Assessment included a DASH score evaluation and an X-ray control.

RESULTS

All of the 7 evaluated patients were satisfied with the operation results. Compared to the opposite side, patients achieved 80.1% (5.9 kg±1.1 kg) of key pinch strength, 86.3% (4.8 kg±0.9 kg) of oppositional tip pinch strength, and 86.1% (23.1 kg±4.8 kg) of grip strength. In combined flexion and opposition a Kapandij index of 8.5 (94.4%) compared to 9 on the opposite side was achieved. Thumb radial abduction was 48.2°±2.8°, compared to 51.0°±2.9° on the contralateral hand. At follow-up, the mean DASH score was 17.8 (±10.0). Radiological control showed no progression of carpometacarpal osteoarthritis of the thumb.

CONCLUSIONS

The collected data after distraction arthroplasty according to Bufalini and Perugia confirm the efficacy of the technique in the early stage of carpometacarpal osteoarthritis of the thumb. Even though a failure rate of 20% occurred, in our opinion the operation is justified in the early stages of carpometacarpal osteoarthritis of the thumb as the patients benefit from a pain-free interval, leaving the option for future trapeziectomy.

[Corion Interposition Arthroplasty after Post-Traumatic Metacarpophalangeal Cartilage Defects - Two Case Reports]

We report on the long-term results of 2 patients after saw injury by restoration of metacarpophalangeal joint II with bone graft from the iliac crest and interposition arthroplasty of the corion. Clinical and radiological controls were performed in the 6(th) and 8(th) post-operative years, respectively. The DASH scores (11.6 and 18.3, respectively) and range of motion (60 and 70° respectively) were associated with no pain and satisfaction with the results of the operation for both patients. In summary, the reconstruction of selected cases of metacarpophalangeal joint defects with iliac crest and corium interposition arthroplasty is a good treatment option.

Formaldehyde chemistry in cometary ices: the case of HOCH2OH formation

Laboratory experiments devoted to simulate the chemistry occurring in interstellar and cometary ice analogues are of paramount importance to understand the formation of complex organic molecules that are detected throughout the universe.

Clinical evaluation of hip joint rotation range of motion in adults

INTRODUCTION

Data on hip joint rotation range of motion (ROM) are rare; the methods of measurement vary and reproducibility has not been evaluated, in particular in relation to the subject's position (prone or supine, seated).

HYPOTHESIS

Hip joint rotation ROM is symmetrical, and ROM is not modified by the patient's position when data is obtained.

PATIENTS AND METHODS

This series included 120 adults between 20 and 60 years old (71 women, 49 men), who had no hip, spine or lower extremity disorders. External (ER) and internal (IR) rotation ROM was obtained using a photographic method by two observers. Measurements were obtained with the patient in three positions: the dorsal decubitus (supine) (P1), and ventral decubitus (prone) (P2) with the hip in extension and seated with the hip in flexion (P3).

RESULTS

Hip rotation ROM was P1: 68.1° (ER=38.5°; IR=29.6°); P2: 77.1°(ER=41.8°; IR=35.2°); P3: 78.5° (ER=78.5°; IR=37.9°) with no significant difference among the three positions. Interobserver reproducibility was satisfactory (concordance correlation coefficient (ccc) 0.7) and was comparable in the three positions with a ccc of 0.7072 (P1), 0.7426 (P2) and 0.7332 (P3), respectively. Hip rotation ROM balance was ER predominant in 47.5%, neutral in 39.5% and IR predominant in 13%. Hip rotation ROM balance was symmetric in both hips in 73 subjects (61%). Hip rotation ROM was reduced with age (P<0.0001), and was 4.7° less in men (P=0.0078), and in overweight subjects (P<0.0006).

DISCUSSION

Our values are probably lower than those in the literature because of the difference in study population. In our series, age, BMI and gender seemed to be determining factors. Hip rotation ROM balance is usually ER predominant or neutral. Hip rotation ROM can be measured in the three positions with no significant difference, with satisfactory interobserver reproducibility for each.

TYPE OF STUDY

Diagnostic prospective study: level III.

Clinical research nursing: a critical resource in the national research enterprise

Translational clinical research has emerged as an important priority for the national research enterprise, with a clearly stated mandate to more quickly deliver prevention strategies, treatments and cures based on scientific innovations to the public. Within this national effort, a lack of consensus persists concerning the need for clinical nurses with expertise and specialized training in study implementation and the delivery of care to research participants. This paper reviews efforts to define and document the role of practicing nurses in implementing studies and coordinating clinical research in a variety of clinical settings, and differentiates this clinical role from the role of nurses as scientists and principal investigators. We propose an agenda for building evidence that having nurses provide and coordinate study treatments and procedures can potentially improve research efficiency, participant safety, and the quality of research data. We also provide recommendations for the development of the emerging specialty of clinical research nursing.

[Resection, interposition and suspension arthroplasty for treatment of Basal joint arthritis of the thumb: a randomized and prospective comparison of techniques using the abductor pollicis longus- and the flexor carpi radialis tendon]

The operative treatment of thumb carpometacarpal joint arthritis may include resection-suspension-interposition-arthroplasty. Although quite a technically demanding procedure, a suspension arthroplasty using a strip of the flexor carpi radialis tendon is quite a popular technique. Other techniques, which use the abductor pollicis longus (APL) tendon, is also widely accepted.The aim of this randomized, prospective study was to compare the results of these 2 procedures 8 months postoperatively.From May 2005 to December 2006 a total of 55 operations in 53 patients with symptomatic Grade III or IV 1st CMC joint arthritis were identified and recruited into the study. They were then randomized to one of the 2 groups (APL vs. FCR). Patients were assessed preoperatively, and then immediately and 8 months postoperatively. Both, subjective parameters (Visual Analog Scale and DASH-Score) and functional parameters (maximum radial abduction, opposition and pinch- and key grip strength) where recorded. Additionally, the trapezial space was assessed radiographically postoperatively.After 8 months both groups had comparable subjective results (APL-group: VAS 2.3 points, DASH 24 points; FCR-group: VAS 1.9 points, DASH 20 points) as well as functional results (APL-group: radial abduction 55.3°, key-grip strength 8.1 kg, pinch-grip strength 5.5 kg; FCR-group: radial abduction 55.8°, key-grip strength 7.2 kg, pinch-grip strength 4.7 kg). Radiologically both groups showed an approximate 50% reduction in the height of the trapezial space.In resection-suspension-interposition-arthroplasty of the 1st CMC joint, similar results can be obtained using the technically less demanding APL-procedure when compared with the FCR-technique 8 months postoperatively.

Circularization, photomechanical switching, and a supercoiling transition of actin filaments

We confine actin filaments onto a 2D surface using depletion interactions and show that this significantly increases the probability of intramolecular circularization. Quantitative analysis reveals that the resulting semiflexible rings fluctuate significantly less then their linear counterparts with equal stiffness-an effect induced by the constraint of circular geometry. When exposed to fluorescence excitation light, rhodamine-phalloidin-labeled filaments undergo a change in their natural twist. This photomechanical transition induces a localized small-wavelength supercoiling transition of absorbed actin rings. Upon completion of the photoinduced reaction, the twist of neighboring monomers in an actin filament changes by approximately 0.26 degrees .

Self-reported syphilis and gonorrhoea testing among men who have sex with men: national HIV behavioural surveillance system, 2003-5

OBJECTIVES

The Centers for Disease Control and Prevention provides guidance on sexually transmitted disease (STD) testing specifically for men who have sex with men (MSM) in STD treatment guidelines to address increasing rates of gonorrhoea and syphilis among MSM in the USA. The guidelines recommend at least annual syphilis, gonorrhoea and chlamydia testing for sexually active MSM. The implementation of these guidelines was evaluated.

METHODS

Data from the 2003-5 MSM cycle of the National HIV Behavioural Surveillance System were used. The proportion of sexually active HIV-negative MSM reporting syphilis and gonorrhoea testing during the previous year was determined and multivariate logistic regression was used to identify factors associated with testing.

RESULTS

Of 10 030 MSM, 39% and 36% reported having been tested for syphilis and gonorrhoea in the previous year, respectively. Four factors were associated with syphilis and gonorrhoea testing, respectively: age 18-24 years versus > or =45 years (odds ratio (OR) 2.2, 95% CI 1.8 to 2.5; OR 2.7, 95% CI 2.3 to 3.2), black versus white race (OR 1.3, 95% CI 1.1 to 1.4; OR 1.4, 95% CI 1.2 to 1.6), private insurance versus no insurance (OR 1.3, 95% CI 1.1 to 1.4; OR 1.3, 95% CI 1.1 to 1.4) and disclosing male-male sex to a healthcare provider (OR 2.2, 95% CI 2.0 to 2.5; OR 2.1, 95% CI 1.9 to 2.3).

CONCLUSIONS

Syphilis and gonorrhoea testing among MSM was low, despite specific testing recommendations in the STD treatment guidelines. To increase STD testing among MSM, healthcare providers should assess the risks of STD for male patients through routine enquiries about sexual activity.

Activation of kinin B receptor triggers differentiation of cultured human keratinocytes

BACKGROUND

Keratinocyte life span is modulated by receptors that control proliferation and differentiation, key processes during cutaneous tissue repair. The kinin B(1) receptor (B(1)R) has been reported in normal and pathological human skin, but so far there is no information about its role in keratinocyte biology.

OBJECTIVES

To determine the consequence of kinin B(1)R stimulation on tyrosine phosphorylation, a key signalling mechanism involved in keratinocyte proliferation and differentiation.

METHODS

Subconfluent primary cultures of human keratinocytes were used to investigate tyrosine phosphorylation, epidermal growth factor receptor (EGFR) transactivation, cell proliferation and keratinocyte differentiation. Cell proliferation was assessed by measuring bromodeoxyuridine incorporation whereas assessment of cell differentiation was based on the expression of filaggrin, cytokeratin 10 (CK10) and involucrin.

RESULTS

The major proteins phosphorylated, after B(1)R stimulation, were of molecular mass 170, 125, 89 and 70 kDa. The 170- and 125-kDa proteins were identified as EGFR and p125(FAK), respectively. Phosphorylation was greatly reduced by GF109203X and by overexposure of keratinocytes to phorbol 12-myristate 13-acetate, indicating the participation of protein kinase C. B(1)R stimulation did not increase [Ca(2+)]i, but triggered EGFR transactivation, an event that involved phosphorylation of Tyr(845), Tyr(992) and Tyr(1068) of EGFR. B(1)R stimulation did not elicit keratinocyte proliferation, but triggered cell differentiation, visualized as an increase of filaggrin, CK10 and involucrin. Blockade of EGFR tyrosine kinase by AG1478, before B(1)R stimulation, produced an additional increase in filaggrin expression.

CONCLUSIONS

The kinin B(1)R may contribute to keratinocyte differentiation and migration by triggering specific tyrosine signalling pathways or by interacting with the ErbB receptor family.

Evaluation of a stuttering treatment based on reduction of short phonation intervals

This paper reports the results of an efficacy study of a stuttering treatment program known as Modifying Phonation Intervals (MPI), which trains stuttering speakers to reduce the frequency of relatively short phonation intervals (PIs) during connected speech across speaking tasks and situations. Five young adult male stuttering speakers were treated in this computer-based program that systematically trains speakers to reduce selected short PIs found to functionally control stuttering. The treatment process was evaluated using multiple-baseline designs. Treatment was largely self-managed and based on a performance-contingent schedule of within-clinic speaking tasks (Establishment), beyond-clinic speaking tasks (Transfer), and systematic decreases in assessment occasions (Maintenance). Assessments were made at regular intervals before, during, and after treatment. All speakers achieved stutter-free and natural-sounding speech during within- and beyond-clinic speaking tasks at the completion of Maintenance. All were tested 12 months after completion of Maintenance, and all maintained the results. The findings from this study suggest that this procedure may make a significant contribution to stuttering treatment practice.

The effect of high molecular phospholipase A2 inhibitors on 3T6 fibroblast proliferation

Recently, we suggested that arachidonic acid and/or its cyclooxygenase pathway metabolites may be involved in regulating 3T6 fibroblast proliferation. In the present study we evaluate the role of high-molecular phospholipase A2 (PLA2) enzymes in the 3T6 fibroblast growth. Our results demonstrate that the cytosolic PLA2 inhibitor, arachidonyl trifluoromethylketone and the cytosolic calcium-independent PLA2 (iPLA2) inhibitor, bromoenol lactone, decrease arachidonic acid release and prostaglandin E2 production in 3T6 fibroblast cultures stimulated by fetal calf serum. These effects were correlated with the impairment of 3T6 fibroblast proliferation and DNA synthesis at the S/G2 boundary, which prolongs the S phase. These data suggest a role of iPLA2 in the control of 3T6 fibroblast growth.

Serum withdrawal-induced post-transcriptional stabilization of cyclooxygenase-2 mRNA in MDA-MB-231 mammary carcinoma cells requires the activity of the p38 stress-activated protein kinase

Overexpression of the cyclooxygenase-2 (COX-2) gene is observed in several neoplastic diseases. However, molecular mechanisms involved in the regulation of expression of COX-2 are not well understood. In this report, we describe a unique post-transcriptional regulatory mechanism of COX-2 mRNA stabilization in MDA-MB-231 cells, a highly metastatic cell line derived from a human mammary tumor. High levels of COX-2 mRNA, protein, and enzyme activity were induced by serum withdrawal, which were potently inhibited by the addition of serum or >100-kDa serum factor. Nuclear run-on analysis and actinomycin D chase experiments indicate that regulation is primarily at the level of post-transcriptional mRNA stability. Interestingly, SB203580, an inhibitor of the p38 stress-activated protein kinase (SAPK), and overexpression of the dominant-negative p38alpha construct potently inhibited the serum withdrawal-induced COX-2 mRNA levels. Indeed, the half-life of COX-2 mRNA decreased from 9 to 4.5 h after SB203580 treatment, suggesting that signal transduction by the p38 SAPK pathway is required for COX-2 mRNA stability.

New agar medium for testing susceptibility of Mycobacterium tuberculosis to pyrazinamide

A new agar medium to perform pyrazinamide (PZA) susceptibility testing with Mycobacterium tuberculosis has been developed. This medium has an acidic pH of 6.0 instead of the usual for agar media, pH 6.8, to provide optimal conditions for PZA activity, and it also differs from conventional Middlebrook 7H10/7H11 agar in that animal serum (fetal or calf bovine or fetal equine serum) is used instead of oleic acid-albumin-dextrose-catalase to support good growth of M. tuberculosis at the low pH of 6.0. A critical concentration of 900 or 1,200 microg of PZA/ml in this medium made it possible to differentiate between PZA-susceptible and PZA-resistant clinical isolates. This agar medium has the following advantages compared to a liquid medium: it allows determination of the actual proportion of PZA-resistant bacteria in the isolate and it is simple and inexpensive. In addition, it has the potential of being used for a direct susceptibility test with PZA, but this approach will require further confirmation. Further studies to develop critical concentrations of other drugs for this low-pH medium, as well as to investigate the possibility of cultivation in regular (non-CO(2)) incubators, are in progress.

Regulation of prostaglandin E2 production by the superoxide radical and nitric oxide in mouse peritoneal macrophages

The purpose of this study was to elucidate the role of NO and O2 on enzymatic components of cyclooxygenase (COX) pathway in peritoneal macrophages. Activation of murine peritoneal macrophages by lipopolysaccharides (LPS) resulted in time-dependent production of nitric oxide (NO) and prostaglandin E2 (PGE2). This stimulation was also accompanied by the production of other reactive oxygen species such as superoxide (O2-), and by increased expression of COX-2. Our results provide evidence that O2- may be involved in the pathways that result in arachidonate release and PGE2 formation by COX-2 in murine peritoneal macrophages stimulated by LPS. However, we were not able to demonstrate that NO participates in the regulation of PG production under our experimental conditions.

Incidence of element distribution on the ultrasonic field of segmented annular arrays

Segmented annular arrays are sometimes used for 3D ultrasonic imaging. However, owing to their geometrical complexity, the acoustic field generated by this type of aperture has not been adequately described. In this work, a method based on the array factor approach is used to describe the field radiated by sector annular arrays. This approach allows one to analyse the influence on the field of several aperture parameters, such as the number of elements per annulus, size and spatial distribution of elements, etc. In addition, strategies to reduce grating lobes are presented.

pncA mutations as a major mechanism of pyrazinamide resistance in Mycobacterium tuberculosis: spread of a monoresistant strain in Quebec, Canada

Pyrazinamide (PZA) is an important first-line tuberculosis drug that is part of the currently used short-course tuberculosis chemotherapy. PZA is a prodrug that has to be converted to the active form pyrazinoic acid by pyrazinamidase (PZase) activity, encoded by the pncA gene of Mycobacterium tuberculosis, and loss of PZase activity is associated with PZA resistance. To further define the genetic basis of PZA resistance and determine the frequency of PZA-resistant strains having pncA mutations, we sequenced the pncA gene from a panel of 59 PZA-resistant clinical isolates from Canada, the United States, and Korea. Two strains that did not contain pncA mutations and had positive PZase turned out to be falsely resistant. Three PZase-negative strains (MIC, >900 microgram of PZA per ml) and one PZase-positive strain (strain 9739) (MIC, >300 microgram of PZA per ml) did not have pncA mutations. The remaining 53 of the 57 PZA-resistant isolates had pncA mutations, confirming that pncA mutation is the major mechanism of PZA resistance. Various new and diverse mutations were found in the pncA gene. Interestingly, 20 PZA-monoresistant strains and 1 multidrug-resistant isolate from Quebec, Canada, all had the same pncA mutation profile, consisting of an 8-nucleotide deletion and an amino acid substitution of Arg140-->Ser. Strain typing indicated that these strains are highly related and share almost identical IS6110 patterns. These data strongly suggest the spread of a PZA-monoresistant strain, which has not previously been described.

Two liquid medium systems, mycobacteria growth indicator tube and MB redox tube, for Mycobacterium tuberculosis isolation from sputum specimens

Two manual liquid medium systems, the Mycobacteria Growth Indicator Tube (MGIT) and MB Redox tube systems, were evaluated in comparison to the radiometric BACTEC-460 semiautomated system for recovery of Mycobacterium tuberculosis from sputum specimens. The highest level of recovery, from a total of 77 culture-positive specimens, occurred with the BACTEC-460 system (92.2%), followed by the MB Redox tube (80.5%) and the MGIT (63.6%) systems. The shortest time to detection was observed also among the cultures in BACTEC-460: a mean of 12 days to a growth index (GI) of 10 and 15 days to a GI of 500. The mean times for the other systems were 16 days for the MB Redox tube system and 17.4 days for the MGIT system. The proportion of cultures grown after more than 3 weeks of incubation was only 2.8 or 8.4% in BACTEC-460 (for a GI of 10 or 500) but 17.7% in MB Redox and 22.5% in MGIT. Despite these differences in comparison to the BACTEC-460 system and some differences between the MGIT and MB Redox tube systems, either of the two manual liquid medium systems presents a reasonable alternative to the BACTEC-460 system, especially for laboratories with a limited workload, and a valuable element in the laboratory protocol, in conjunction with solid media, for obtaining rapid detection of growth from about 80% of culture-positive specimens and for better overall recovery of M. tuberculosis.

Development of rifapentine susceptibility tests for Mycobacterium tuberculosis

Two methods for testing the susceptibility of Mycobacterium tuberculosis to rifapentine have been developed: the agar proportion method and the radiometric BACTEC technique. A critical concentration of 0.5 microg of rifapentine per ml is proposed for both methods since it provides a reliable means of distinguishing between susceptible and resistant M. tuberculosis isolates. It is recommended that two quality control M. tuberculosis strains be used at the introduction of these tests in a clinical laboratory: one that is pansusceptible (H37Rv) and one that is resistant to rifapentine. The resistant strain can be obtained from the American Type Culture Collection, where it is deposited under the number ATCC 700457.

Induction by interleukin-1beta peptide of prostaglandin E2 formation via enhanced prostaglandin H synthase-2 expression in 3T6 fibroblasts

Several synthetic interleukin-1 (IL-1) peptides were tested in vivo for pyrogenic activity and in vivo for their ability to stimulate prostaglandin production. Only the IL-1beta fragment (208-240) enhanced body temperature, although both IL-1beta (208-240) and IL-1alpha (223-250) stimulated prostaglandin E2 (PGE2) production in vitro. We report here that the IL-1beta fragment (208-240) did not have the capacity to induce arachidonic acid (AA) mobilization by 3T6 fibroblasts. However, this peptide was able to increase the expression of the inducible prostaglandin H synthase isoform (PGHS-2; EC 1.14.99.1.), which is related to its ability to stimulate prostaglandin E2 synthesis.

Gonadotropin secretion and development of ovarian follicles during oestrous cycles in heifers treated with luteinizing hormone releasing hormone antagonist

The hypothesis tested was that reduced LHRH stimulation of the anterior pituitary would lead to attenuated development of ovarian follicles as a result of reduced gonadotropin secretion during oestrous cycles of cattle. Twenty heifers were randomly assigned to be treated ( n = 5/treatment) with an antagonist to LHRH (LHRH-Ant) 1) from Day 2 to 7 (Day 0 = behavioural oestrus), 2) Day 7 to 12, 3) Day 12 to 17, 4) or serve as untreated control animals. LHRH-Ant suppressed LH pulses of heifers in all treatment groups from treatment initiation through Day 17 as compared with untreated control heifers [Peters et al., 1994. Luteinizing hormone has a role in development of fully functional corpora lutea (CL) but is not required to maintain CL function in heifers. Biol. Reprod., 51 (1994) 1248-1254]. Circulating concentration of FSH from Day 8 to 10 of the oestrous cycle did not increase in heifers treated with LHRH-Ant from Day 2 to 7 or Day 7 to 12; however, there was increased (P < 0.05) FSH from Day 8 to 10 of the oestrous cycle in heifers treated with LHRH-Ant from Day 12 to 17 and control heifers. Compared with control heifers, heifers treated with LHRH-Ant from the Day 2 to 7 had suppressed (P < 0.05) size and persistence of the first and second dominant ovarian follicles. Heifers treated with LHRH-Ant from Day 7 to 12 had suppressed size (P < 0.05 and tended (P < 0.10) to have a shorter persistence of the second dominant ovarian follicle compared with control heifers. Heifers treated with LHRH-Ant from Day 12 to 17 had a similar (P > 0.10) size and persistence of dominant ovarian follicles but had reduced (P < 0.10) numbers of large follicles compared with control heifers. Heifers treated with LHRH-Ant from Day 2 to 7 had lower (P < 0.01) concentrations of 17 beta-oestradiol during the treatment period and tended (P < 0.10) to have lower concentrations of 17 beta-oestradiol from Day 7 to 12 of the oestrous cycle compared with control heifers. Heifers treated with LHRH-Ant from Day 7 to 12 or Day 12 to 17 had similar (P > 0.10) circulating LH concentrations of l7 beta-oestradiol compared with control heifers. Reduced LHRH stimulation of the pituitary from Day 2 to 12 of the oestrous cycle and the resulting modulation in circulating LH and FSH led to suppressed ovarian follicular development and oestradiol secretion. After Day 12 of the oestrous cycle, reduced LHRH stimulation of the anterior pituitary did not lead to altered ovarian follicular development to the extent as reduced LHRH stimulation before Day 12 although pulsatile release of LH was similarly suppressed by treatment with the LHRH-Ant.

Role of prostaglandin H synthase-2-mediated conversion of arachidonic acid in controlling 3T6 fibroblast growth

The specific role(s) of arachidonic acid (AA) and its metabolites in the signaling pathways that regulated fibroblast growth was studied. A Western blot analysis demonstrated that prostaglandin H synthase-2 (PGHS-2) was expressed by 3T6 fibroblast cultures in RPMI 1640 supplemented with fetal calf serum (10%). Dexamethasone, which inhibits AA release and PGHS-2 expression, significantly reduced cell proliferation. Ketoprofen, a dual cyclooxygenase inhibitor, and CGP-28238, a specific PGHS-2 inhibitor, reduced fibroblast proliferation in a dose-dependent manner. These drugs also reduced [3H]thymidine incorporation into the DNA of fibroblasts. These effects were correlated with a decrease in prostaglandin (PG) E2 levels in the cell medium. However, piroxicam at doses that selectively inhibit PGHS-1 did not have a significant effect on fibroblast proliferation. Finally, we showed that the antiproliferative effect of dexamethasone and PGHS-2 inhibitors was significantly antagonized when PGE2 was added to the culture medium. Our results suggest that PGHS-2 and prostaglandins such as PGE2 might play an important role in the regulation of 3T6 fibroblast growth stimulated by growth factors of serum.

Incidence of precocious puberty in developing beef heifers

The objectives of this study were to determine the incidence of precocious puberty and effect of exposure to a bull on the incidence of precocious puberty in beef heifers. The experiment was conducted using 120 heifers during 1990 and 1991. Heifer calves were randomly assigned to be pastured in the presence (n = 30 heifers/yr) or absence (n = 30 heifers/yr) of a bull starting at 140 +/- 14 d of age for the duration of the study. Heifers were 402 +/- 14 d of age at the time the study was completed. Blood samples were collected weekly to determine the age of onset, duration and cessation of luteal function. Heifers were considered to have exhibited a precocious puberty when the onset of luteal function was before 300 d of age. There was no effect of exposure to a bull on the incidence of precocious puberty, and therefore the data were pooled. The incidence of precocious puberty was greater (P < .02; X2 = 5.5) in 1990 (25.0%; 15 of 60) compared with 1991 (8.3%; 5 of 60). There was no effect of year on age of precocious puberty (194 +/- 12.4 d of age), duration of cyclic luteal function (65 +/- 10.5 d), or the age at resumption of anestrus (260 +/- 15.3 d of age). Precocious puberty does occur in developing beef heifers; as many as 25% of heifers have transient luteal function before 300 d of age. However, exposure to a bull has no effect on the incidence of precocious puberty.

Changing dose of progesterone results in sudden changes in frequency of luteinizing hormone pulses and secretion of 17 beta-estradiol in bovine females

The aim of the present study was to elucidate the time course according to which changes in circulating concentrations of progesterone influence pulsatile secretion of LH and secretion of 17 beta-estradiol. Our working hypothesis was that changing the dose of progesterone would result in changes in frequency of LH pulses and secretion of 17 beta-estradiol within 72 h. Five days after behavioral estrus, thirty-three cows were randomly assigned to one of five groups: 1) control, no treatment (CONT, n = 5); 2) treatment with two progesterone-releasing intravaginal devices (PRIDs) for 11 days (2PRID, 5-6 ng/ml plasma progesterone, n = 7); 3) treatment with a 0.5 PRID for 11 days (0.5PRID, 1-2 ng/ml plasma progesterone, n = 7); 4) treatment with 2 PRIDs for 8 days followed by treatment with a 0.5 PRID for 3 days (2-0.5PRID, n = 7); and 5) treatment with a 0.5 PRID for 8 days followed by treatment with 2 PRIDs for 3 days (0.5-2PRID, n = 7). Cows subject to PRID treatments received injections of prostaglandin F2 alpha on Days 1 and 2 (Day 0 = day of initiation of PRID treatments, fifth day of the estrous cycle in CONT cows) to lyse the existing corpus luteum. Cows were bled for 12 h at 15-min intervals on Day 7.5 of the treatment period (twelfth day of the estrous cycle in CONT cows). The dose of progesterone was changed on Day 8 in cows that were assigned to the 2-0.5PRID and 0.5-2PRID groups, and blood collections continued an additional 72 h to characterize profiles of circulating concentrations of LH and 17 beta-estradiol. Cows treated with a 0.5 PRID had a greater (p < 0.05) number of LH pulses and higher (p < 0.05) concentrations of 17 beta-estradiol throughout the entire blood collection period than cows in the 2PRID and CONT groups. An increase in the number of LH pulses was detected within 6 h after the change from the high to the low dose of progesterone (2-0.5PRID), and frequency of LH pulses was similar to that of cows in the 0.5PRID group for the remainder of the period of blood collection. LH pulse frequency declined within 6 h after the shift from the low to the high dose of progesterone (0.5-2PRID) and was similar to that of cows in the 2PRID group by 12 h after the dose was changed. Within 6 h after the dose of progesterone was changed, circulating concentrations of 17 beta-estradiol increased (p < 0.05) in cows shifted from the high to low dose (2-0.5PRID) and declined (p < 0.05) after the dose of progesterone was changed from low to high (0.5-2PRID). We conclude that changing the circulating concentrations of progesterone concurrently affects frequency of pulsatile LH release and secretion of 17 beta-estradiol within 6-24 h.