VRE acquisition in hospital and its association with hospital antimicrobial usage -a non-linear analysis of an extended time series

BACKGROUND

Vancomycin resistant enterococci (VRE) have become endemic pathogens in many Australian hospitals causing significant morbidity. There are few observational studies that have evaluated the effect of antibiotic usage on VRE acquisition. This study examined VRE acquisition and its association with antimicrobial use. The setting was a NSW tertiary hospital with 800 beds over a 63 month period up to March 2020, straddling piperacillin-tazobactam (PT) shortages that occurred from in September 2017.

METHODS

The primary outcome was monthly inpatient hospital onset Vancomycin-resistant Enterococci (VRE) acquisitions. Multivariate adaptive regression splines (MARS) were used to estimate hypothetical thresholds, where antimicrobial use above threshold is associated with increased incidence of hospital onset VRE acquisition. Specific antimicrobials and categorised usage (broad, less broad and narrow spectrum) were modelled.

RESULTS

There were 846 hospital onset VRE detections over the study period. Hospital onset vanB and vanA VRE acquisitions fell significantly by 64% and 36% respectively after the PT shortage. MARS modelling indicated that PT usage was the only antibiotic found to exhibit a meaningful threshold. PT usage greater than 17.4 defined daily doses/1000 occupied bed-days (95%C I: 13.4, 20.5) was associated with higher onset of hospital VRE.

CONCLUSIONS

This paper highlights the large, sustained impact that reduced broad spectrum antimicrobial use had on VRE acquisition and showed that PT use in particular was a major driver with a relatively low threshold. It raises the question as to whether hospitals should be determining local antimicrobial usage targets based on direct evidence from local data analysed with non-linear methods.

The association between diabetes and mortality in young adults presenting with myocardial infarction

Background

The incidence of diabetes mellitus and coronary artery disease continue to rise and collectively comprise two of the most prevalent and costly diseases worldwide. The goal of this study is to report the prognosis of young patients with diabetes presented with acute myocardial infarction (AMI).

Methods

This is a retrospective observational cohort study that included consecutive patients aged 18–45 years who underwent cardiac catheterization for AMI between 2006 and 2016 in an integrated healthcare system in Southern California. The prognosis of patients with diabetes were compared to those without diabetes.

Results

A total of 1,560 patients (average age 40.2±5.3 years, 25.6% female) presenting with AMI were included. Of these 272 (17.4%) had diabetes. Diabetics were older (41.1±4.4 vs 40.0±5.4 years), more likely to be female (32.4% vs 24.1%, p=0.006), Hispanic (51.5% vs 40.5%, p<0.001), have a higher body mass index (BMI) (33.6±7.1 vs 31.2±6.8kg/m2, p<0.001), have hypertension (HTN) (67.6% vs 23.8%, p<0.001), hyperlipidemia (HLD) (78.3% vs 24.1%, p<0.001), peripheral vascular disease (9.9% vs 1.9%, p<0.001), chronic kidney disease (CKD) (23.2% vs 2.7%, p<0.001), hypothyroidism (7% vs 4%, p=0.034), and prior strokes (4.4% vs 2.2%, p=0.034).

On multivariate analysis accounting for other cardiovascular risk factors, the association remained significant (OR 1.82, 95% CI 1.04–3.19, p=0.036). At a median follow-up of 5.8 years (interquartile range 3.7–8.7 years), diabetes was independently associated with increased all-cause mortality (Hazard ratio [HR] 3.10, 95% CI 1.68–5.69, p<0.001) when adjusting for age, sex, race, BMI, HTN, HLD, CKD, hypothyroidism, prior stroke, and ACS etiology. In a propensity score matched cohort, diabetes remained significantly associated with all-cause mortality (HR 5.29, 95% CI 2.34–12.02, p<0.001).

Conclusion

Diabetes is an independent predictor of increased mortality in young adults <45 years old presenting with AMI.

Funding Acknowledgement

Type of funding sources: Private hospital(s). Main funding source(s): KAISER PERMANENTE LOS ANGELES MEDICAL CENTER

Choice of primary and secondary outcomes in randomised controlled trials evaluating treatment for uterine fibroids: a systematic review

BACKGROUND

Core outcome sets aim to reduce research heterogeneity and standardise reporting, allowing meaningful comparisons between studies.

OBJECTIVES

To report on outcomes used in randomised controlled trials (RCTs) investigating uterine fibroid treatments, towards the development of a core outcome set for fibroid research.

SELECTION STRATEGY

Database search of MEDLINE, PubMed, EMBASE and CINAHL (inception to July 2021) for all English-language RCTs involving surgical or radiological fibroid treatments.

DATA COLLECTION AND ANALYSIS

A total of 1885 texts were screened for eligibility by two reviewers independently according to PRISMA methodology. JADAD and Management of Otitis Media with Effusion in Cleft Palate (MOMENT) scores were used to assess methodological and outcome reporting quality of studies, respectively. Outcomes were mapped to nine domains. Non-parametric tests for correlation and to compare group medians were undertaken.

MAIN RESULTS

There were 23 primary outcomes (23 outcome measures) and 173 secondary outcomes (95 outcome measures) reported in 60 RCTs (5699 participants). The domains with highest frequency of primary outcomes reported were bleeding and quality of life (QoL). The most frequent primary outcomes were postoperative pain, QoL and menstrual bleeding. No primary outcomes were mapped to fertility domains. Median MOMENT outcome score was 5 (interquartile range 3). There was correlation between MOMENT outcome score and JADAD scores (r = 0.491, P = 0.0001), publishing journal impact factor (r = 0.419, P = 0.008) and publication year (r = 0.332, P = 0.01).

CONCLUSION

There is substantial variation in the outcomes reported in fibroid RCTs. There is a need for a core outcome set for fibroid research, to allow improved understanding regarding the effects of different treatments.

Triggers of stress cardiomyopathy and their association with clinical outcomes

Background

Stress cardiomyopathy can be a result of physical stress, emotional stress, or both. Whether the type of trigger affects clinical outcomes is not well studied.

Purpose

The objectives of this study were to identify the prevalence of emotional and physical stressors and to assess differences in patient characteristics and mortality based on the type of trigger.

Methods

We conducted a retrospective review of 523 consecutive patients who presented to our institution from 2006 to 2016. All patients presented with acute coronary syndrome. Triggers for stress cardiomyopathy were abstracted from reviewing patients' medical records. Patients were categorized into those with 1) physical trigger, 2) emotional trigger, 3) both physical and emotional trigger, or 4) no known trigger. Baseline characteristics and clinical outcomes were reported.

Results

Among 523 patients with stress cardiomyopathy, 151 (28.9%) had a physical trigger, 189 (36.1%) had an emotional trigger, 30 (5.7%) had both physical and emotional triggers, and 153 (29.3%) had no known triggers identified. Men comprised the higher proportion of patients with physical triggers. Comorbidities including diabetes, pulmonary disease, chronic kidney disease and hypothyroidism were more prevalent among patients with physical triggers. Compared to patients with no obvious triggers, patients with a physical trigger had a much higher mortality rate (hazard ratio 2.0, 95% CI 1.2–3.3, p=0.007), whereas patients with an emotional trigger had significantly lower mortality (hazard ratio 0.40, 95% CI 0.21–0.89, p=0.007).

Conclusion

Different triggers for stress cardiomyopathy is associated with different baseline characteristics and clinical outcomes. Overall survival is worst in the group with an identified physical trigger.

Figure 1

Funding Acknowledgement

Type of funding source: None

Screening for high hip fracture risk does not impact on falls risk: a post hoc analysis from the SCOOP study

A reduction in hip fracture incidence following population screening might reflect the effectiveness of anti-osteoporosis therapy, behaviour change to reduce falls, or both. This post hoc analysis demonstrates that identifying high hip fracture risk by FRAX was not associated with any alteration in falls risk.

INTRODUCTION

To investigate whether effectiveness of an osteoporosis screening programme to reduce hip fractures was mediated by modification of falls risk in the screening arm.

METHODS

The SCOOP study recruited 12,483 women aged 70-85 years, individually randomised to a control (n = 6250) or screening (n = 6233) arm; in the latter, osteoporosis treatment was recommended to women at high risk of hip fracture, while the control arm received usual care. Falls were captured by self-reported questionnaire. We determined the influence of baseline risk factors on future falls, and then examined for differences in falls risk between the randomisation groups, particularly in those at high fracture risk.

RESULTS

Women sustaining one or more falls were slightly older at baseline than those remaining falls free during follow-up (mean difference 0.70 years, 95%CI 0.55-0.85, p < 0.001). A higher FRAX 10-year probability of hip fracture was associated with increased likelihood of falling, with fall risk increasing by 1-2% for every 1% increase in hip fracture probability. However, falls risk factors were well balanced between the study arms and, importantly, there was no evidence of a difference in falls occurrence. In particular, there was no evidence of interaction (p = 0.18) between baseline FRAX hip fracture probabilities and falls risk in the two arms, consistent with no impact of screening on falls in women informed to be at high risk of hip fracture.

CONCLUSION

Effectiveness of screening for high FRAX hip fracture probability to reduce hip fracture risk was not mediated by a reduction in falls.

The pharmacokinetics of pimobendan enantiomers after oral and intravenous administration of racemate pimobendan formulations in healthy dogs

Pimobendan is a benzimidazole-pyridazinone derivative, marketed as a racemic mixture for the management of canine heart failure. Pharmacokinetics of the enantiomers of pimobendan and its oral bioavailability have not been described in dogs. The aim of this study was to describe pharmacokinetics of three formulations of pimobendan in healthy dogs: the licensed capsule product, and novel liquid and intravenous formulations. A three-period, nested randomized two-treatment crossover design was used. Pimobendan was administered p.o. at 0.25 and i.v. at 0.125 mg/kg. Blood and plasma samples were analysed by liquid chromatography-mass spectrometry. Noncompartmental modelling was used to describe the pharmacokinetics. Parameters were compared between formulations using a general linear model. Bioequivalence of the oral formulations was tested using CI90 for AUC(0-∞) and Cmax . Bioavailability of pimobendan after oral dosing was 70%. Liquid and capsule formulations were bioequivalent only for AUC. The positive enantiomer of pimobendan (PE) had a larger volume of distribution than the negative enantiomer (NE) (281 ± 48 vs. 215 ± 68 mL/kg; P = 0.003) and a shorter half-life (21.7 vs. 29.9 min; P = 0.004). The NE was distributed more quickly than the PE into blood cells. Enantiomers of pimobendan have differing absorption, distribution and elimination. The pharmacokinetics of pimobendan in healthy dogs was described.

Reprogramming the tumor microenvironment: tumor-induced immunosuppressive factors paralyze T cells

It has become evident that tumor-induced immuno-suppressive factors in the tumor microenvironment play a major role in suppressing normal functions of effector T cells. These factors serve as hurdles that limit the therapeutic potential of cancer immunotherapies. This review focuses on illustrating the molecular mechanisms of immunosuppression in the tumor microenvironment, including evasion of T-cell recognition, interference with T-cell trafficking, metabolism, and functions, induction of resistance to T-cell killing, and apoptosis of T cells. A better understanding of these mechanisms may help in the development of strategies to enhance the effectiveness of cancer immunotherapies.

Pictogram-based method of visualizing dietary intake

BACKGROUND

Pictograms have been shown by many studies to be an effective way of conveying information. An easy-to-understand pictorial description is essential for communication of dietary intake in the computer era.

OBJECTIVES

We proposed a novel approach that represents textual descriptions of dietary intake into a pictorial representation with the concept of pictograms. The computational implementation in terms of a web-based tool was investigated on how well the pictograms carry their intended message.

METHODS

1) We investigated how well the pictograms are comprehended in terms of subjects' accuracy rate and response time. In the study (n = 90), pictorial variants with three types of food images (black-and-white sketch, colored sketch, and colored photograph) were tested. 2) We also investigated how well subjects were able to select the standard food size among various food portions with the use of the tool. A comparison was made against the current standard of an educational session taught by a registered dietitian. We recruited 86 university students who were asked to select a standard size out of five different size categories. Three types of shapes were used. The bowl is the container that is widely used in the participants' country. The pork strip was to represent foods with elliptical cross-section. The apple was used to represent a baseball-like size and shape.

RESULTS

Two pictograms with black-and-white food image were low of less than 50% in accuracy rate. The rest of the twenty-seven pictograms derived from portions of the nine foods were well understood with high accuracy rates (above 85%). Participants in using the tool without the dietitian's session was better than participants in the dietitian education session in selecting a standard portion size of an apple (p < 0.0001; p = 0.0009 after adjustment for gender and age). The rate of correct bowl and pork strip size estimates were similar between the two conditions (p > 0.05).

CONCLUSION

The development of pictograms could be used as a computational visual aid for comprehending and identifying dietary intake. Broader investigation is required for considering the effectiveness of the pictograms on recall, measurement, or estimation as well as for further evaluation in the clinical practice.

Effect of fructose on markers of non-alcoholic fatty liver disease (NAFLD): a systematic review and meta-analysis of controlled feeding trials

BACKGROUND/OBJECTIVES

In the absence of consistent clinical evidence, there are concerns that fructose contributes to non-alcoholic fatty liver disease (NAFLD). To determine the effect of fructose on markers of NAFLD, we conducted a systematic review and meta-analysis of controlled feeding trials.

SUBJECTS/METHODS

We searched MEDLINE, EMBASE, CINAHL and the Cochrane Library (through 3 September 2013). We included relevant trials that involved a follow-up of ≥ 7 days. Two reviewers independently extracted relevant data. Data were pooled by the generic inverse variance method using random effects models and expressed as standardized mean difference (SMD) for intrahepatocellular lipids (IHCL) and mean difference (MD) for alanine aminotransferase (ALT). Inter-study heterogeneity was assessed (Cochran Q statistic) and quantified (I(2) statistic).

RESULTS

Eligibility criteria were met by eight reports containing 13 trials in 260 healthy participants: seven isocaloric trials, in which fructose was exchanged isocalorically for other carbohydrates, and six hypercaloric trials, in which the diet was supplemented with excess energy (+21-35% energy) from high-dose fructose (+104-220 g/day). Although there was no effect of fructose in isocaloric trials, fructose in hypercaloric trials increased both IHCL (SMD=0.45 (95% confidence interval (CI): 0.18, 0.72)) and ALT (MD=4.94 U/l (95% CI: 0.03, 9.85)).

LIMITATIONS

Few trials were available for inclusion, most of which were small, short (≤ 4 weeks), and of poor quality.

CONCLUSIONS

Isocaloric exchange of fructose for other carbohydrates does not induce NAFLD changes in healthy participants. Fructose providing excess energy at extreme doses, however, does raise IHCL and ALT, an effect that may be more attributable to excess energy than fructose. Larger, longer and higher-quality trials of the effect of fructose on histopathological NAFLD changes are required.

Number of suture throws and its impact on the biomechanical properties of the four-strand cruciate locked flexor tendon repair with FiberWire

FiberWire is a popular suture in flexor tendon repair that allows for early mobilization, but its poor knot-holding properties have raised concerns over the potential effects on tendon healing and strength. We examined how the number of knot throws affects the 2 mm gap force, ultimate tensile strength, and mode of failure in a four-strand cruciate locked tendon repair in porcine flexor tendons in order to elucidate the optimal number of suture throws. There was no effect on the 2 mm gap force with increasing knot throws, but there was a significant increase in ultimate tensile strength. A minimum of six-knot throws prevents unravelling, whereas five out of 10 of repairs unravelled with less than six throws.

The health of homeless immigrants

BACKGROUND

This study examined the association between immigrant status and current health in a representative sample of 1189 homeless people in Toronto, Canada.

METHODS

Multivariate regression analyses were performed to examine the relationship between immigrant status and current health status (assessed using the SF-12) among homeless recent immigrants (< or = 10 years since immigration), non-recent immigrants (>10 years since immigration) and Canadian-born individuals recruited at shelters and meal programmes (response rate 73%).

RESULTS

After adjusting for demographic characteristics and lifetime duration of homelessness, recent immigrants were significantly less likely to have chronic conditions (RR 0.7, 95% CI 0.5 to 0.9), mental health problems (OR 0.4, 95% CI 0.2 to 0.7), alcohol problems (OR 0.2, 95% CI 0.1 to 0.5) and drug problems (OR 0.2, 95% CI 0.1 to 0.4) than non-recent immigrants and Canadian-born individuals. Recent immigrants were also more likely to have better mental health status (+3.4 points, SE +/-1.6) and physical health status (+2.2 points, SE +/-1.3) on scales with a mean of 50 and a SD of 10 in the general population.

CONCLUSION

Homeless recent immigrants are a distinct group who are generally healthier and may have very different service needs from other homeless people.

A novel cationic cardiolipin analogue for gene delivery

The optically active R and S isomers of cationic cardiolipin analogues (CCA) were synthesized and evaluated as a liposome based transfection reagent. Both isomers form stable liposomes with mean diameters of about 120 nm without any additional lipid ingredients. No significant change in particle size distribution profile was observed over one-month storage at room temperature (20-25 degrees C). The gel to liquid crystalline phase transition temperature (Tm) of cationic liposomes comprised of both R and S isomers was approximately 2 degrees C, as measured by differential scanning calorimetry (DSC). Both isomers also formed stable liposomes when combined with DOPE. In vitro transfection efficiency of the CCA/DOPE liposomes complexed to plasmid DNA was evaluated using a luciferase reporter gene. Both liposomes composed of R and S isomers of the cationic cardiolipin displayed higher transfection efficiency than commercially available Lipofectin. Further in vivo studies are warranted.

Longitudinal outcome of verbal discourse in children with traumatic brain injury: three-year follow-up

PURPOSE

This study compared changes in discourse ability between two groups of children age 5 to 10 years after brain injury: those with severe traumatic brain injury (TBI) and those with mild/moderate injury over 3-year follow-up testing.

MATERIALS AND METHODS

Forty-three children with TBI were recruited from a larger research project examining cognitive and linguistic recovery after injury. Twenty-two of these patients had severe injuries and 21 sustained mild/moderate injuries. All children were presented an ordered sequence of pictures and asked to verbally produce a story/narrative discourse. Each child was then asked to produce a lesson relating to the story.

RESULTS

The severe group performed significantly worse than the mild/moderate group when performance across all four discourse domains was considered. Both groups improved across time on selected discourse measures. Qualitative analysis suggested that the severe group showed differential rates of improvement across the individual discourse variables over the 3-year interval.

CONCLUSIONS

Severe TBI can have a pernicious effect on discourse abilities in children years after injury compared with children with mild/moderate injuries. The major caveat is that the discourse measures must be sufficiently challenging when used to assess older children and children with milder forms of TBI.

Human and mouse ABCA1 comparative sequencing and transgenesis studies revealing novel regulatory sequences

The expression of ABCA1, a major participant in apolipoprotein-mediated cholesterol efflux, is regulated by a variety of factors, including intracellular cholesterol concentration. To identify sequences involved in its regulation, we sequenced and compared approximately 200 kb of mouse and human DNA containing the ABCA1 gene. Furthermore, expression of the human gene containing different 5' ends was examined in transgenic mice. Sequence comparison revealed multiple conserved noncoding sequences. The two most highly conserved noncoding elements (CNS1, 88% identity over 498 bp; CNS2, 81% identity over 214 bp) were also highly conserved in other organisms. Mice containing the human ABCA1 gene, 70 kb of upstream DNA, and 35 kb of downstream DNA expressed the transgene similarly to endogenous Abca1. A second transgene beginning 3' to exon 1 was expressed only in liver, providing strong evidence of an unsuspected liver-specific promoter. The identified conserved noncoding sequences invite further investigation to elucidate ABCA1 regulation.

Inverse agonist binding of peripheral benzodiazepine receptors in anxiety disorder

The binding characteristics of the pBR (peripheral benzodiazepine receptor) inverse agonist, [3H]-Ro 5-4864, were examined in patients diagnosed as generalized anxiety disorder. As compared to normal healthy controls, the anxious subjects demonstrated a statistically significant (p < 0.001) increase in the density of pBR in platelets. The enhanced pBR binding correlated significantly with the severity of global anxiety symptom of the Hamilton Anxiety Rating Scale (HAR-S, p < 0.001). The Psychic component, but not the Somatic component, of the HAR-S, correlated significantly (p < 0.001) with the enhanced pBR binding in platelets. The results provide evidence for the hypothesis of dysregulation of peripheral benzodiazepine receptors in generalized anxiety disorder.

Phthalocyanine 4 photodynamic therapy-induced apoptosis of mouse L5178Y-R cells results from a delayed but extensive release of cytochrome c from mitochondria

Photodynamic therapy (PDT) activates the mitochondrial pathway of apoptosis, for which the release of cytochrome c into the cytosol is considered critical. To further elucidate the role of cytochrome c release in PDT-induced apoptosis, we monitored cytochrome c localization immunocytochemically and related it to nuclear apoptosis of the same cells. When mouse L5178Y-R cells were treated with 300 nM phthalocyanine (Pc) 4 and 0-75 mJ/cm(2) red light, cytochrome c release had a dose response similar to that of clonogenic cell killing, with nearly identical threshold doses. Within individual cells, the release of cytochrome c appeared to be an all-or-none phenomenon. Moreover, it was tightly associated with activation of a caspase-3-like protease and changes in nuclear morphology. Thus, in response to Pc 4-PDT, the release of cytochrome c from mitochondria is a key determinant of apoptotic cell death.

Septic arthritis of the hip caused by Salmonella typhi

We describe septic arthritis of the hip in a child with typhoid fever. The aetiological diagnosis was confirmed by a positive Widal test as well as by isolation of Salmonella typhi from joint aspirate. Treatment with ceftriaxone along with surgical drainage was successful.

The role of amino acid neurotransmitters in the regulation of pituitary gonadotropin release in fish

Both glutamate and gamma-aminobutyric acid (GABA) are involved in pituitary hormone release in fish. Glutamate serves 2 purposes, both as a neurotransmitter and as a precursor for GABA synthesis. Glutamate can be catabolized to GABA by the actions of 2 distinct but related enzymes, glutamate decarboxylase 65 (GAD65) and GAD67. They derive from 2 different genes that likely arose from an early gene duplication prior to the emergence of teleosts more than 400 million years ago. There is good evidence for the involvement of GABA in luteinizing hormone (LH) release in fish. The mechanism of GABA action to stimulate LH release appears to be a combination of effects on GnRH release, potentiation of gonadotropin hormone-releasing hormone (GnRH) action, and in some cases directly at the LH cell. These actions appear to be dependent on such factors as sex or sex steroid levels, and there may also be species differences. Nevertheless, the stimulatory effects of GABA on LH are present in at least 4 fish species. In contrast, convincing data for the inhibitory effects of GABA on LH release have only been observed in 1 fish species. The sites and mechanisms of action of amino acid neurotransmitters on LH release have yet to be fully characterized. Both 130N-methyl-D-aspartic acid (NMDA) and S-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) type glutamate receptors are likely to have important roles. We suggest that it is a receptor similar to the GABA(A) type which mediates the effects of GABA on LH release in fish, at least partially acting on the GnRH neuron, but likely directly acting at the gonadotroph as well. GABA may also be involved in regulating the release of other pituitary hormones in fish, namely follicle stimulating hormone (FSH = GTH-I), prolactin, and growth hormone. Based on the findings described in this review, a working model for the involvement of glutamate and GABA in the regulation of LH release in teleost fish is proposed.

Two double-blinded, randomized, comparative trials of 4 human immunodeficiency virus type 1 (HIV-1) envelope vaccines in HIV-1-infected individuals across a spectrum of disease severity: AIDS Clinical Trials Groups 209 and 214

The potential role of human immunodeficiency virus type 1 (HIV-1)-specific immune responses in controlling viral replication in vivo has stimulated interest in enhancing virus-specific immunity by vaccinating infected individuals with HIV-1 or its components. These studies were undertaken to define patient populations most likely to respond to vaccination, with the induction of novel HIV-1-specific cellular immune responses, and to compare the safety and immunogenicity of several candidate recombinant HIV-1 envelope vaccines and adjuvants. New lymphoproliferative responses (LPRs) developed in <30% of vaccine recipients. LPRs were elicited primarily in study participants with a CD4 cell count >350 cells/mm(3) and were usually strain restricted. Responders tended to be more likely than nonresponders to have an undetectable level of HIV-1 RNA at baseline (P=.067). Induction of new cellular immune responses by HIV-1 envelope vaccines is a function of the immunologic stage of disease and baseline plasma HIV-1 RNA level and exhibits considerable vaccine strain specificity.

Surgical validation and implications for transcatheter closure of quantitative echocardiographic evaluation of atrial septal defect

Accurate evaluation of secundum atrial septal defect (ASD) is important for the success of transcatheter closure. The purpose of this study was (1) to describe a quantitative evaluation by transthoracic (TTE) and transesophageal (TEE) echocardiography of the various morphologic features of ASD that might be important for patient selection for transcatheter closure, and (2) to assess the reliability of these 2 methods by surgical findings. Preoperative TTE and TEE were used to evaluate the ASD of 27 children undergoing surgical closure. Measurements included the diameters of ASD and the atrial septal lengths in the transverse and longitudinal axis, and the width of the superior, inferior, anteroinferior, and posterior septal margins. The shape and location of the ASD and the adequacy of the septal margins for anchoring occluding devices were determined. Echocardiographic data were compared with corresponding surgical measurements. No significant difference occurred in the means of all the parameters measured with the 3 methods, except for the transverse ASD diameter (p <0.05). Good agreement occurred between TTE and TEE and surgical data, except for the transverse ASD diameter, transverse atrial septal length, and the posterior septal margin on TTE. Intraclass correlations between TTE and TEE and surgical measurements of all parameters were good, except for the transverse ASD diameter. The accuracy in determining shape and location of the ASD by TTE and TEE were 100%, whereas that for determining the adequacy of septal margins was 98% and 97%, respectively. In conclusion, TTE and TEE are reliable methods for quantitative evaluation of ASD.

The role of amino acid neurotransmitters in the regulation of pituitary gonadotropin release in fish

Both glutamate and γ-aminobutyric acid (GABA) are involved in pituitary hormone release in fish. Glutamate serves 2 purposes, both as a neurotransmitter and as a precursor for GABA synthesis. Glutamate can be catabolized to GABA by the actions of 2 distinct but related enzymes, glutamate decarboxylase 65 (GAD65) and GAD67. They derive from 2 different genes that likely arose from an early gene duplication prior to the emergence of teleosts more than 400 million years ago. There is good evidence for the involvement of GABA in luteinizing hormone (LH) release in fish. The mechanism of GABA action to stimulate LH release appears to be a combination of effects on GnRH release, potentiation of gonadotropin hormone-releasing hormone (GnRH) action, and in some cases directly at the LH cell. These actions appear to be dependent on such factors as sex or sex steroid levels, and there may also be species differences. Nevertheless, the stimulatory effects of GABA on LH are present in at least 4 fish species. In contrast, convincing data for the inhibitory effects of GABA on LH release have only been observed in 1 fish species. The sites and mechanisms of action of amino acid neurotransmitters on LH release have yet to be fully characterized. Both N-methyl-D-aspartic acid (NMDA) and S-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) type glutamate receptors are likely to have important roles. We suggest that it is a receptor similar to the GABAA type which mediates the effects of GABA on LH release in fish, at least partially acting on the GnRH neuron, but likely directly acting at the gonadotroph as well. GABA may also be involved in regulating the release of other pituitary hormones in fish, namely follicle stimulating hormone (FSH = GTH-I), prolactin, and growth hormone. Based on the findings described in this review, a working model for the involvement of glutamate and GABA in the regulation of LH release in teleost fish is proposed.

Key words: glutamate, GABA, luteinizing hormone, muscimol, patch clamp electrophysiology, reproduction, fish.

Reduced mobilization of CD34+ stem cells in advanced human immunodeficiency virus type 1 disease

Granulocyte colony-stimulating factor (r-met Hu G-CSF; filgrastim; 10 microgram/kg/day for 7 days) was used to mobilize CD34+stem cells into the peripheral blood of human immunodeficiency virus type 1 (HIV-1)-infected individuals and a group of HIV-1-uninfected donors as a measure of immunologic reserve in HIV-1-infected people. G-CSF mobilized CD34+ cells of HIV-1-infected individuals with cell counts >500 CD4+ cells/mm3, as well as in HIV-1-uninfected donors. In contrast, CD34 cell mobilization was significantly blunted in HIV-1-infected individuals with cell counts <500 CD4+ cells/mm3 (<200 cell days vs. >650 cell days, P<.0005, compared with the >500 CD4+ cell cohort). At least 1.75x10(7) CD34 cells were harvested by leukapheresis from patients in each study cohort. CD34+ cell viability and the ability to differentiate precursor cells into myeloid and erythroid progenitor cells were not affected by HIV-1 infection.

Secretory event in intestinal grafts during preservation ischemia

BACKGROUND

Ischemia triggers secretion of proteins from the intestine, including type II secretory phospholipase A2 (sPLA2). This "secretory event" was studied in intestinal grafts during the first few hours of preservation by measuring total protein, sPLA2, and other enzymes in the UW preservation solution over time. The effect of PX-13, a PLA2 inhibitor, was also studied.

MATERIALS AND METHODS

Twenty-five centimeter intestinal grafts were harvested from Lewis rats, flushed, and preserved in UW solution +/- PX-13 at 4 degrees C. UW samples from 0 to 48 h (n = 5 each) were analyzed for total protein, sPLA2, lactate dehydrogenase (LDH), N-acetylglucosamine (NAGA), and lysozyme. Nonpreserved grafts were homogenized in PBS as tissue controls. Standard biochemical methods were used for all assays.

RESULTS

Total protein increased rapidly by 5 min, continued to rise more slowly until 30 min, and then stabilized. The most significant increase in sPLA2 activity occurred between 90 and 180 min. NAGA increased most markedly between 30 and 180 min, while LDH increased in the first 30 min, although the level of both enzymes was negligible compared to tissue enzyme. Lysozyme levels were minimal at all times. PX-13 decreased sPLA2 activity markedly at all time points.

CONCLUSION

Total protein levels increased before sPLA2, suggesting that sPLA2 may be secreted in response to other proteins or enzymes released even earlier during preservation (e.g., cytokines). These elevations do not appear to be caused by cell death. Phospholipase A2 secretion may be blocked, and this may greatly improve the outcome of intestinal preservation.

Characterization of the analgesic and anti-inflammatory activities of ketorolac and its enantiomers in the rat

The marked analgesic efficacy of ketorolac in humans, relative to other nonsteroidal anti-inflammatory drugs (NSAIDs), has lead to speculation as to whether additional non-NSAID mechanism(s) contribute to its analgesic actions. To evaluate this possibility, we characterized (R,S)-ketorolac's pharmacological properties in vivo and in vitro using the nonselective cyclooxygenase (COX) inhibitors [indomethacin (INDO) and diclofenac sodium (DS)] as well as the selective COX-2 inhibitor, celecoxib, as references. The potency of racemic (R,S)-ketorolac was similar in tests of acetic acid-induced writhing, carrageenan-induced paw hyperalgesia, and carrageenan-induced edema formation in rats; ID50 values = 0.24, 0. 29, and 0.08 mg/kg, respectively. (R,S)-ketorolac's actions were stereospecific, with (S)-ketorolac possessing the biological activity of the racemate in the above tests. The analgesic potencies for (R,S)-, (S)-, and (R)-ketorolac, INDO, and DS were highly correlated with their anti-inflammatory potencies, suggesting a common mechanism. (R,S)-ketorolac was significantly more potent than INDO or DS in vivo. Neither difference in relative potency of COX inhibition for (R,S)-ketorolac over INDO and DS nor activity of (S)-ketorolac at a number of other enzymes, channels, or receptors could account for the differences in observed potency. The distribution coefficient for (R,S)-ketorolac was approximately 30-fold less than for DS or INDO, indicating that (R,S)-ketorolac is much less lipophilic than these NSAIDs. Therefore, the physicochemical and pharmacokinetics properties of (R,S)-ketorolac may optimize the concentrations of (S)-ketorolac at its biological target(s), resulting in greater efficacy and potency in vivo.

Radioprotection of cellular chromatin by the polyamines spermine and putrescine: preferential action against formation of DNA-protein crosslinks

Spermine is an efficient radioprotector of plasmid or viral DNA and of viral minichromosomes by a mechanism involving radical scavenging and the induction of compaction and aggregation of DNA. Based on radioprotection of SV40 minichromosomes at a lower spermine concentration than needed for SV40 DNA, Newton et al. (Radiat. Res. 145, 776-780, 1996) proposed that the differential concentration dependence could account for the greater radiosensitivity of open regions of cellular chromatin compared to bulk inactive chromatin at physiological levels of spermine. However, we recently reported that, whereas the effects of spermine on the formation of DNA double-strand breaks (DSBs) in dehistonized V79 cell DNA (nucleoids) were consistent with spermine-induced DNA compaction, spermine provided no radioprotection of native chromatin and only modest radioprotection of histone H1-depleted chromatin (Chiu and Oleinick, Radiat. Res. 148, 188-192, 1997). To further characterize the radioprotection of cellular chromatin by spermine, radiation-induced DNA-protein crosslinks (DPCs) were investigated, because of evidence that these lesions occur preferentially at or near the sites of anchorage of chromosomes to the nuclear matrix. In contrast to the relatively inefficient radioprotection of V79 cell chromatin against the formation of DSBs, low concentrations (<0.1 mM) of spermine or putrescine provided partial radioprotection against the formation of DPCs in both native and H1-depleted chromatin. Whereas all DPCs generated by the irradiation of chromatin, above the level generated in intact cells, could be blocked by 5 mM spermine, less than half could be blocked by 5 mM putrescine. The difference in efficiency of radioprotection of native chromatin by the two polyamines can be accounted for by assuming that the binding of spermine is 10 times as efficient as the binding of putrescine. The results suggest that (a) both spermine and putrescine bind preferentially and with high affinity at matrix-associated sites of formation of DPCs, disrupting the associations between DNA and protein that are essential for formation of DPCs and/or scavenging hydroxyl radicals at these sites; (b) a smaller fraction of the sites are susceptible to putrescine than to spermine; and (c) endogenous spermine is a major radioprotector of cells against the formation of DPCs, either because of specific features of the lesion or because of the site of lesion formation at the nuclear matrix.

Capillary electrophoresis determinative and LC-MS confirmatory method for screening selected imidazolinone herbicides from soil

Residues of imazapyr, imazamox, imazapic, imazethapyr, imazaquin, and imazamethabenz (meta and para) are extracted from soil with 0.5 N sodium hydroxide. The pH is adjusted to 2.0-2.2, and the resulting precipitate is filtered. Compounds are trapped onto a tC18 solid-phase extraction (SPE) cartridge, then eluted from the cartridge and passed through a strong anion exchange (SAX) SPE cartridge onto a benzenesulfonic acid strong cation exchange (SCX) cartridge using ethyl acetate. After eluting the analytes from the SCX cartridge using saturated potassium chloride in methanol, the solution is evaporated and redissolved in 1% formic acid in water. The sample is then desalted using a tC18 SPE cartridge and eluted with methanol. After evaporating the methanol to dryness, the compounds are partitioned from acidic solution (pH 3.5) into methylene chloride. The methylene chloride is evaporated to dryness and the residues are then dissolved in Milli-Q water (Millipore, Bedford, MA, U.S.A.) in preparation for analysis by capillary electrophoresis. Results are calculated by direct comparison of the sample peak heights to the peak heights of bracketing standards. The validated sensitivity of the method (LOQ, limit of quantitation) is 2.0 ppb for each compound. Confirmation for individual residues greater than 2.0 ppb is provided by liquid chromatography-electrospray ionization mass spectrometry (LC-ESMS) of the final extract.

Radioprotection against the formation of DNA double-strand breaks in cellular DNA but not native cellular chromatin by the polyamine spermine

The complexing of histones with DNA and the resulting condensation of chromatin protect mammalian cell DNA from radiation-induced strand breakage. In recent studies of SV40 DNA and minichromosomes, marked radioprotection was afforded by spermine through polyamine-induced compaction and aggregation (Newton et al., Radiat. Res. 145, 776-780, 1996). To evaluate the contribution of polyamines to the radioprotection of cellular chromatin, intact V79 cells, nuclei (native chromatin) and chromatin that was partially or completely stripped of histones were treated with spermine or putrescine and gamma-irradiated while embedded in agarose plugs, and induction of double-strand breaks was determined by pulsed-field gel electrophoresis. In the absence of added spermine, the order of radiosensitivity was: dehistonized chromatin (DNA loops anchored to the nuclear matrix) > chromatin depleted of histone H1 > chromatin partially depleted of histone H1 > native chromatin > intact cells. Spermine at concentrations below 1 mM was without effect on strand breakage in any of the preparations, except for limited radioprotection of H1-depleted chromatin. Increasing radioprotection with increasing concentration (1-10 mM) was provided to dehistonized chromatin by spermine but not by putrescine, a polyamine that does not compact DNA or chromatin. Significant radioprotection by spermine was also found for H1-depleted relaxed chromatin at concentrations > or = 1 mM. In contrast, no radioprotection by spermine (up to 10 mM) was observed for any of the chromatin preparations containing all histones. These observations support the hypothesis proposed by Newton et al. that spermine protects DNA against radiation damage via polyamine-induced compaction and aggregation. With removal of histone H1, the exposed chromatin develops the ability to be protected by spermine. However, the absence of radioprotection of native chromatin by spermine is consistent with a role for histones as the major radioprotectors of cellular DNA and the differential radiosensitivity of decondensed compared to condensed cellular chromatin resulting from the effects of factors other than polyamines.

Prolactin receptor gene expression in specific hypothalamic nuclei increases with age

Increasing prolactin levels or increasing responsiveness to prolactin may contribute to reproductive aging by influencing the secretory patterns of hypothalamic GnRH, pituitary gonadotropins, and/or ovarian steroids. Some studies have documented changes in the levels of prolactin in peripheral plasma. The goal of this study was to determine whether prolactin receptor mRNA levels in the brain change with aging, which may lead to increasing responsiveness to prolactin. Young (2-4 months) and middle-aged (9-11 months), demonstrating 3 consecutive estrous cycles, and old (16-19 months) and very old (20-21 months) rats, exhibiting repeated pseudopregnancies, were bilaterally ovariectomized. They were implanted with Silastic capsules containing estradiol-17 beta one week later, and killed 2 days after capsule implantation. Changes in prolactin receptor gene expression were assessed using in situ hybridization. The level of prolactin receptor mRNA in choroid plexus, periventricular area of the preoptic nucleus, and arcuate nucleus increased significantly by the time the animals were old. In the lateral ventromedial nucleus, prolactin receptor gene expression did not change significantly during aging, even in the oldest group of rats. These findings suggest that changes in the prolactin receptor gene may influence the ability of prolactin to exert effects and may allow older animals to be more responsive to prolactin than young rats.

Crystallization and preliminary X-ray diffraction study of the flavoenzyme 2,4-pentadienoyl-CoA reductase from Clostridium aminovalericum

The tetrameric flavoenzyme 2,4-pentadienoyl-CoA reductase has been crystallized from solutions containing polyethylene glycol as precipitant. The crystals grow in the monoclinic space group C2 with unit-cell dimensions a = 160.2, b = 120.2, c = 95.3 A, beta = 99.0 degrees. The packing parameter V(M) is 2.3 A(3) Da(-1) (Matthews parameter) for four monomers per asymmetric unit. Complete data sets to about 2.9 A resolution have been collected.

Nuclear structure and the microdistribution of radiation damage in DNA

Evidence for the roles of proteins and metal ions in the microheterogeneity of DNA damage is reviewed. Decondensation of chromatin in hypotonic buffers markedly sensitizes the DNA to radiation, while treatment of nuclei with hypertonic buffers strips the DNA of histones and other nuclear proteins and enhances the radiosensitivity of the DNA with respect to double-strand break (dsb) formation. Addition of the radical scavenger DMSO reduces the yield of strand breaks, but dehistonized chromatin remains approximately 2.5 times more sensitive to radiation than does native chromatin at 0.1 M DMSO. DNA-protein crosslink (DPC) formation is relatively unaffected by the removal of the majority of histones from chromatin. Most DPC form at or near the nuclear matrix, and matrix is stabilized and radiosensitized by Cu++. To elucidate the role of Cu++, the induction of dsb and DPC by gamma-radiation has been compared with that by hydroxyl radical from Fe(++)-EDTA, or Cu++ catalysed Fenton reactions. Data comparing the size of DNA fragments produced, the effect of expanding or dehistonizing chromatin, and the effects of radical scavengers suggest that gamma-radiation and Fe(++)-EDTA produce dsb at open chromatin sites, whereas Cu(++)-generated dsb are similar to radiation-induced DPC in their location at the nuclear matrix. Both metal ions appeared to produce damage by site-specific generation of hydroxyl radicals. The nuclear matrix, the proteinaceous skeleton which anchors chromosomal loops and provides sites for DNA replication and transcription, binds metal ions and matrix-attachment DNA regions (MARs) consisting of 300 + bp of AT-rich DNA. The interaction of cloned MARs with isolated nuclear matrices has been found to be hypersensitive to crosslinking upon gamma-irradiation, in comparison with associations formed by similarly sized DNA fragments lacking MAR sequences. Thus, the non-random distribution of radiation damage is partially explained by the protection of DNA afforded by histones and chromatin structure and partially by the hypersensitivity of DNA-nuclear matrix associations.

Neuroendocrine concomitants of reproductive aging

Depletion of ovarian follicles is often thought to be the determining factor in female reproductive aging. However, increasing evidence suggests that neural and neuroendocrine changes play important causative roles in the decline of regular reproductive cycles leading to the menopause. A blunting or suppression in the daily pattern of secretion of several neuroendocrine hormones has been documented in aging laboratory animals and humans. Investigators have designed experiments to test whether these changes reflect multiple unrelated changes in the regulation of each of these hormones, or whether these alterations result from a fundamental change in the time-keeping mechanism that underlie these patterns of hormone secretion. Oscillations that occur approximately every 24 h are a hallmark of most living organisms. These cycles provide the organism with the capability of coordinating events that occur at higher (hourly) and lower (weekly or monthly) frequencies within an individual organism, and with the capability of synchronizing these events with the external environment. In mammals, the hypothalamic suprachiasmatic nucleus is thought to be a master oscillator that regulates most circadian rhythms in mammals. Perturbations in temporal organization occur during aging and influence multiple physiological systems, including reproductive cyclicity in females. Thus, the question for neuroendocrinologists is: Do changes in the cyclic pattern of hormone secretion reflect a change in the master oscillator, and do these changes play a role in female reproductive aging? Data from our laboratory demonstrate that the timing of the preovulatory and steroid-induced luteinizing hormone (LH) surge changes during middle-age in rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Prolactin receptor mRNA localization in the hypothalamus by in situ hybridization

Prolactin receptors may mediate the action of prolactin in the brain to influence behavior and neuroendocrine secretions. We recently demonstrated prolactin receptor gene expression in the anterior and medial basal hypothalamus and not in the cortex by the reverse transcription-polymerase chain reaction. In this paper, we localize the prolactin receptor gene expression to individual cells with in situ hybridization. Several steps in the in situ hybridization method were modified to increase sensitivity by using (i) probes complementary to the coding sequence of the extracellular binding domain common to both long and short prolactin receptor, (ii) more stringent hybridization and wash conditions to reduce background and (iii) higher specific activity, more complex and saturating amounts of probe. We detected prolactin receptor gene expression in cells of the periventricular area of the preoptic nucleus, medial preoptic nucleus, supraoptic nucleus, rostral arcuate nucleus and choroid plexus. Cortical brain tissue, which has been demonstrated previously by reverse-transcription polymerase chain reaction to be lacking in prolactin receptor mRNA, did not have any detectable signal for the receptor mRNA and was used as an indication of background levels of signal. The mean area of silver grains over labeled cells in periventricular area of the preoptic nucleus, medial preoptic nucleus, supraoptic nucleus, arcuate nucleus, lateral ventromedial nucleus was at least 10 times greater than the background in the cortex of the same brain section.

Quantitative-analysis of silver staining nucleolar organizer regions (AgNORs) in human tongue carcinoma cell-lines

Six morphometric parameters related to nuclear size, number of AgNORs, and area of AgNORs in two tongue carcinoma cell lines were analyzed by an image analyzing system. It was discovered that AgNOR numbers, the area of all AgNORs in the nucleus, the ratio of mean area and size, and nuclear size are the parameters demonstrating the most consistent pattern of change against passage numbers in T1 and T2 human tongue carcinoma cells. These changes may be related to 'dedifferentiation' of tumor cells in prolonged culture.

Three-dimensional dosimetry for radioimmunotherapy treatment planning

Absorbed-dose calculations for radioimmunotherapy are generally based on tracer imaging studies of the labeled antibody. Such calculations yield estimates of the average dose to normal and target tissues assuming idealized geometries for both the radioactivity source volume and the target volume. This work describes a methodology that integrates functional information obtained from SPECT or PET with anatomical information from CT or MRI. These imaging modalities are used to define the actual shape and position of the radioactivity source volume relative to the patient's anatomy. This information is then used to calculate the spatially varying absorbed dose, depicted in "colorwash" superimposed on the anatomical imaging study. By accounting for individual uptake characteristics of a particular tumor and/or normal tissue volume and superimposing resulting absorbed-dose distribution over patient anatomy, this approach provides a patient-specific assessment of the target-to-surrounding normal tissue absorbed-dose ratio. Such information is particularly important in a treatment planning approach to radioimmunotherapy, wherein a therapeutic administration of antibody is preceded by a tracer imaging study to assess therapeutic benefit.