The association of trauma with self-reported flares and disease activity in systemic lupus erythematosus (SLE)

OBJECTIVES

Trauma has been linked to incident SLE, but its relationship with SLE disease activity is unknown. This analysis examines associations between trauma exposures and patient-reported SLE disease activity and flares.

METHODS

Data were from the California Lupus Epidemiology Study (CLUES). Flares were self-reported as any flare and, of those, flares accompanied by medical care (hospitalization or physician contact). The Systemic Lupus Activity Questionnaire (SLAQ) assessed disease activity. The Brief Trauma Questionnaire (BTQ) assessed all historical trauma exposures. The Adverse Childhood Experiences (ACEs) questionnaire was available for a subset. Multivariable regression analyses (n = 252) examined whether trauma exposure was associated with flares or SLAQ controlling for age, sex, poverty, race/ethnicity, comorbidities, perceived stress, disease duration and self-reported disease damage.

RESULTS

Excluding exposure to serious illness, 63.4% reported ≥1 trauma exposure. Any traumatic event, excluding illness, doubled the odds of a flare [OR 2.27 (95% CI 1.24, 4.17)] and was associated with significantly higher SLAQ scores [β 2.31 (0.86, 3.76)]. Adjusted odds of any flare and flare with medical care were significantly elevated for those with both BTQ and ACE exposures [5.91 (2.21, 15.82) and 4.69 (1.56, 14.07), respectively]. SLAQ scores were also higher for those with both exposures [β 5.22 (3.00, 7.44)].

CONCLUSION

In this cohort, those with a history of trauma reported more flares and greater disease activity. Identifying mechanisms of associations between trauma and disease activity and flares, as well as interventions to mitigate the effects of trauma exposures is critical, given the high rates of trauma exposures.

Physical Activity Associates With Lower Systemic Inflammatory Gene Expression in Rheumatoid Arthritis

OBJECTIVE

While general population studies have shown inverse associations between physical activity and common inflammatory biomarkers, the effects of physical activity on inflammatory gene expression and signaling pathways in rheumatoid arthritis (RA) remain unknown. We aimed to determine whether physical activity independently associates with expression of inflammatory genes among people with RA.

METHODS

This was a prospective observational study of adults with RA. Physical activity was measured by quantitative actigraphy over 7 consecutive days, and peripheral blood collected during the same time period was used for RNA sequencing followed by differential gene expression, pathway, and network analyses.

RESULTS

Actigraphy and RNA sequencing data were evaluated in 35 patients. The cohort had a mean age of 56 (SD 12) years, and was 91% female, 31% White, 9% Black, 9% Asian, and 40% Hispanic. We found 767 genes differentially expressed (adjusted P < 0.1) between patients in the greatest vs lowest physical activity tertiles, after adjusting for sex, age, race, and ethnicity. The most active patients exhibited dose-dependent downregulation of several immune signaling pathways implicated in RA pathogenesis. These included CD40, STAT3, TREM-1, interleukin (IL)-17A, IL-8, Toll-like receptor, and interferon (IFN) signaling pathways. Upstream cytokine activation state analysis predicted reduced activation of tumor necrosis factor-α and IFN in the most active group. In sensitivity analyses, we adjusted for RA disease activity and physical function and found consistent results.

CONCLUSION

Patients with RA who were more physically active had lower expression of immune signaling pathways implicated in RA pathogenesis, even after adjusting for disease activity, suggesting that physical activity may confer a protective effect in RA.

Increased rates of secondary bacterial infections, including Enterococcus bacteremia, in patients hospitalized with coronavirus disease 2019 (COVID-19)

OBJECTIVE

We compared the rates of hospital-onset secondary bacterial infections in patients with coronavirus disease 2019 (COVID-19) with rates in patients with influenza and controls, and we investigated reports of increased incidence of Enterococcus infections in patients with COVID-19.

DESIGN

Retrospective cohort study.

SETTING

An academic quaternary-care hospital in San Francisco, California.

PATIENTS

Patients admitted between October 1, 2019, and October 1, 2020, with a positive SARS-CoV-2 PCR (N = 314) or influenza PCR (N = 82) within 2 weeks of admission were compared with inpatients without positive SARS-CoV-2 or influenza tests during the study period (N = 14,332).

METHODS

National Healthcare Safety Network definitions were used to identify infection-related ventilator-associated complications (IVACs), probable ventilator-associated pneumonia (PVAP), bloodstream infections (BSIs), and catheter-associated urinary tract infections (CAUTIs). A multiple logistic regression model was used to control for likely confounders.

RESULTS

COVID-19 patients had significantly higher rates of IVAC and PVAP compared to controls, with adjusted odds ratios of 4.7 (95% confidence interval [CI], 1.7-13.9) and 10.4 (95 % CI, 2.1-52.1), respectively. COVID-19 patients had higher incidence of BSI due to Enterococcus but not BSI generally, and whole-genome sequencing of Enterococcus isolates demonstrated that nosocomial transmission did not explain the increased rate. Subanalyses of patients admitted to the intensive care unit and patients who required mechanical ventilation revealed similar findings.

CONCLUSIONS

COVID-19 is associated with an increased risk of IVAC, PVAP, and Enterococcus BSI compared with hospitalized controls, which is not fully explained by factors such as immunosuppressive treatments and duration of mechanical ventilation. The mechanism underlying increased rates of Enterococcus BSI in COVID-19 patients requires further investigation.

Physical Inactivity and Incident Depression in a Multiracial, Multiethnic Systemic Lupus Erythematosus Cohort

OBJECTIVE

Physical activity is known to improve depressive symptoms. The present study was undertaken to examine physical inactivity as a predictor of incident depression in systemic lupus erythematosus (SLE).

METHODS

Data derive from the California Lupus Epidemiology Study (CLUES), a longitudinal cohort with confirmed SLE diagnoses. Physical inactivity was assessed from a single item, "I rarely or never do any physical activities," and depressive symptoms by the 8-item Patient Health Questionnaire (PHQ-8). Analysis included those not depressed at baseline (PHQ-8 score <10) who completed an in-person baseline assessment and at least 1 follow-up visit (n = 225). Incident depression was defined as a PHQ-8 score of ≥10 at follow-up. Cox proportional hazards regression modeled incident depression over 2 years as a function of baseline physical inactivity, controlling for age, sex, race, income, comorbidities, disease activity, and disease damage.

RESULTS

At baseline, the mean ± SD age of the participants was 45 ± 15 years, 88% were female, and 70% identified as non-White. Mean PHQ scores for those without depression at baseline did not differ by activity status, but those who were inactive at baseline were significantly more likely to develop depression over the next 2 years (hazard ratio [HR] 2.89 [95% confidence interval (95% CI) 1.46-5.71]). After adjusting for covariates, the association remained strong, including a >3-fold increased risk of incident depression among the sedentary group (HR 3.88 [95% CI 1.67-9.03]).

CONCLUSION

In this diverse SLE cohort, a simple question about physical inactivity was highly predictive of incident depression over the subsequent 2 years. Results suggest an urgent need for approaches to reduce sedentary behavior in this high-risk population.

Obesity is Independently Associated With Worse Patient-Reported Outcomes in Women with Systemic Lupus Erythematosus

OBJECTIVE

To determine whether obesity in women with systemic lupus erythematosus (SLE) is independently associated with worse patient-reported outcomes (PROs).

METHODS

Data were derived from a prospective study of adult women with a diagnosis of SLE that was verified by medical record review. Two established definitions for obesity were used: fat mass index (FMI) ≥13 kg/m² and body mass index (BMI) ≥30 kg/m² . Dependent variables included 4 validated PROs: disease activity as assessed by the Systemic Lupus Activity Questionnaire (SLAQ), depressive symptoms as assessed by the Center for Epidemiologic Studies Depression Scale (CES-D), pain as assessed by the Short Form 36 (SF-36) pain subscale, and fatigue as assessed by the SF-36 vitality subscale. We used multivariable linear regression to evaluate the associations of obesity with PROs, while controlling for potential confounders (age, race, education, income, smoking, disease duration, disease damage, and prednisone use).

RESULTS

The analysis included 148 participants, 32% of whom were obese. In the multivariate regression model, obesity was associated with worse scores for each PRO. Mean adjusted scores for the SLAQ and CES-D comparing obese versus non-obese participants were 14.8 versus 11.5 (P = 0.01) and 19.8 versus 13.1 (P < 0.01), respectively. The obese group also reported worse mean adjusted scores for pain (38.7 versus 44.2; P < 0.01) and fatigue (39.6 versus 45.2; P = 0.01).

CONCLUSION

In a representative sample of women with SLE, obesity (as defined by both FMI and BMI) was independently associated with worse PROs, including disease activity, depressive symptoms, and symptoms of pain and fatigue. Obesity may represent a modifiable target for improving outcomes among obese women with SLE.

Pneumocystis jirovecii pneumonia (PJP) prophylaxis patterns among patients with rheumatic diseases receiving high-risk immunosuppressant drugs

INTRODUCTION/OBJECTIVES

Pneumocystis jirovecii pneumonia (PJP) is a rare but potentially fatal opportunistic infection; however, consensus varies around which conditions or medications confer a level of risk sufficient to justify antibiotic prophylaxis for PJP. We used electronic health record (EHR) data to assess the current patterns of PJP prophylaxis, PJP outcomes, and prophylaxis-related adverse events among patients with rheumatic diseases who were receiving high-risk immunosuppressant drugs.

METHODS

Data derive from the EHR of a large health system. We included new immunosuppressant users with diagnoses of vasculitis, myositis, or systemic lupus erythematosus. We calculated the proportion of patients who received PJP prophylaxis for each diagnosis and drug combination. We also calculated the number of PJP infections and the number of antibiotic adverse drug events (ADEs) per patient-year of exposure.

RESULTS

We followed 316 patients for 23.2 + /- 14.2 months. Overall, 124 (39%) of patients received prophylactic antibiotics for PJP. At least 25% of patients with the highest risk conditions (e.g. vasculitis) or highest risk immunosuppressants (e.g. cyclophosphamide) did not receive PJP prophylaxis. We found no cases of PJP infection over 640 patient-years of follow up, including among those not receiving prophylaxis, and an overall incidence rate of ADEs of 2.2% per patient-year.

CONCLUSIONS

PJP prophylaxis for patients with rheumatic conditions is inconsistent, with one quarter of patients who have high risk conditions or high risk immunosuppressants not receiving prophylaxis. However, given extremely low rates of PJP infection, but detectable ADEs to prophylactic antibiotics, our findings suggest that evidence to guide more personalized risk assessments are needed to inform PJP prophylaxis.

Discordance of the Framingham cardiovascular risk score and the 2013 American College of Cardiology/American Heart Association risk score in systemic lupus erythematosus and rheumatoid arthritis

Despite the increasing use of the 2013 American College of Cardiology/American Heart Association (ACC/AHA) cardiovascular (CV) risk score in clinical practice, few studies have compared this score to the Framingham risk score among rheumatologic patients. We calculated Framingham and 2013 ACC/AHA risk scores in subjects with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) and assessed demographic, CV, and rheumatologic characteristics associated with discordant scores (high-risk ACC/AHA scores but low-risk Framingham scores). SLE and RA subjects drawn from two population-based cohort studies were assessed during in-person study visits. We used chi-squared tests and t tests to examine the association of discordant CV risk scores with baseline characteristics. Eleven (7.0%) of 157 SLE subjects and 11 (11.5%) of 96 RA subjects had discordant CV risk scores with high ACC/AHA scores and low Framingham scores. These findings did not significantly change when a 1.5 multiplier was applied to the Framingham score. Rheumatologic disease duration, high-sensitivity CRP levels, African-American race, diabetes, current use of anti-hypertensive medication, higher age, and higher systolic blood pressure were each significantly associated with discordant risk scores. Approximately 10% of SLE and RA subjects had discordant 10-year CV risk scores. Our findings suggest that the use of the 2013 ACC/AHA risk score could result in changes to lipid-lowering therapy recommendations in a significant number of rheumatologic patients. Prospective studies are needed to compare which score better predicts CV events in rheumatologic patients, especially those with risk factors associated with discordant risk scores.

Neuromyelitis Optica

Neuromyelitis optica (NMO), formerly known as Devic disease, is an autoimmune astrocytopathic disease characterized by transverse myelitis and optic neuritis. Most patients demonstrate a relapsing course with incomplete recovery between attacks, resulting in progressive disability. The pathogenesis involves production of aquaporin-4 antibodies (AQP4-IgG) by plasmablasts in peripheral circulation, disruption of the blood-brain barrier, complement-mediated astrocyte injury, and secondary demyelination. The diagnosis relies on characteristic clinical manifestations in the presence of serum AQP4-IgG positivity or specific neuroimaging findings, and exclusion of alternative etiologies. Current treatment involves aggressive immunosuppression with pulse-dose steroids during acute attacks and long-term immunosuppression for attack prevention.

Sociocultural factors affecting uptake of home-based neonatal thermal care practices in Africa: A qualitative review

Neonatal hypothermia is a major contributor to neonatal mortality in sub-Saharan Africa, often as a comorbidity of severe infections, preterm births or asphyxia. Simple, cost-effective thermal care practices (TCPs) immediately at birth and in the post-natal period are recommended in the World Health Organization 'warm chain'. Current practices are suboptimal in the home in low-resource settings, where approximately half of neonatal deaths occur. Several databases (PubMed, OVID SP, Web of Science, The Cochrane Library and Google Scholar) were searched for original research on home-based TCPs. Seventeen articles were identified, and the results were analysed using a 'thermal care behavioural model'. This review of the qualitative literature on home-based practices across Africa illuminates the sociocultural factors affecting the uptake of recommended practices and strategies for behaviour change. Findings from the review confirm that potentially harmful cultural norms and traditions influence the sequence of TCPs in different contexts across Africa. Furthermore, caregiver factors and contextual barriers or facilitating factors to TCPs and behaviour change exist. Hypothermia and home-based TCPs are areas for further research. Thermal care behaviour change interventions tailored to the sociocultural context are necessary to improve neonatal outcomes in Africa.

Role of muscle-derived growth factors in bone formation

Muscle and bone anabolism and catabolism are tightly coupled during growth, development, and aging, yet the cellular and molecular mechanisms linking these two tissues are not well understood. Here we show that FGF-2 and IGF-1, two growth factors known to play a major role in regulating bone formation, are localized to muscle fibers along the muscle-bone interface of the mouse forelimb. Likewise, receptors for these growth factors are also abundant in periosteum adjacent to fleshy muscle attachments along the diaphysis of long bones. Growth factor levels were quantified from homogenized mouse forelimb muscles and IGF-1 was found to be the most abundant factor with FGF-2 also detected. Growth factor levels were also analyzed in conditioned medium from cultured myotubes, and IGF-1 and FGF-2 were again detected at significant levels. Mechanically wounding C2C12 myotubes increased the release of FGF-2 into conditioned medium, whereas IGF-1 was secreted at lower concentrations than FGF-2 following injury. Together these findings suggest that muscle is an important, local source of growth factors for bone tissue. Hence, the integrated growth and development of bone and muscle is likely to be regulated in part by paracrine mechanisms at the muscle-bone interface involving growth factor signaling.

Antileishmanial and antimalarial chalcones: synthesis, efficacy and cytotoxicity of pyridinyl and naphthalenyl analogs

The antileishmanial and antimalarial activity of methoxy-substituted chalcones (1,3-diphenyl-2-propen-1-ones) is well established. The few analogs prepared to date where the 3-phenyl group is replaced by either a pyridine or naphthalene suggest these modifications are potency enhancing. To explore this hypothesis, sixteen 3-naphthalenyl-1-phenyl-2-prop-1-enones and ten 1-phenyl-3-pyridinyl-2-prop-1-enones were synthesized and their in vitro efficacies against Leishmania donovani and Plasmodium falciparum determined. One inhibitor with submicromolar efficacy against L. donovani was identified (IC50 = 0.95 microM), along with three other potent compounds (IC50 < 5 microM), all of which were 3-pyridin-2-yl derivatives. No inhibitors with submicromolar efficacy against P. falciparum were identified, though several potent compounds were found (IC50 < 5 microM). The cytotoxicity of the five most active L. donovani inhibitors was assessed. At best the IC50 against a primary kidney cell line was around two-fold higher than against L. donovani. Being more active than pentamidine, the 1-phenyl-3-pyridin-2-yl-2-propen-1-ones have potential for further development against leishmaniasis; however it will be essential in such a program to address not only efficacy but also their potential for toxicity.

Some forms of cAMP-mediated long-lasting potentiation are associated with release of BDNF and nuclear translocation of phospho-MAP kinase

Long-lasting forms of synaptic plasticity like the late phase of LTP (L-LTP) typically require an elevation of cAMP, the recruitment of the cAMP-dependent protein kinase (PKA), and ultimately the activation of transcription and translation; some forms also require brain-derived neurotrophic factor (BDNF). Both cAMP and BDNF can activate mitogen-activated protein kinase (MAPK/ERK), which also plays a role in LTP. However, little is known about the mechanisms whereby cAMP, BDNF, and MAPK interact. We find that increases in cAMP can rapidly activate the BDNF receptor TrkB and induce BDNF-dependent long-lasting potentiation at the Schaffer collateral-CA1 synapse in hippocampus. Surprisingly, in these BDNF-dependent forms of potentiation, which are also MAPK dependent, TrkB activation is not critical for the activation of MAPK but instead appears to modulate the subcellular distribution and nuclear translocation of the activated MAPK.

A novel transverse push-pull microprobe: in vitro characterization and in vivo demonstration of the enzymatic production of adenosine in the spinal cord dorsal horn

Adenosine produces analgesia in the spinal cord and can be formed extracellularly through enzymatic conversion of adenine nucleotides. A transverse push-pull microprobe was developed and characterized to sample extracellular adenosine concentrations of the dorsal horn of the rat spinal cord. Samples collected via this sampling technique reveal that AMP is converted to adenosine in the dorsal horn. This conversion is decreased by the ecto-5'-nucleotidase inhibitor, alpha,beta-methylene ADP. Related behavioral studies demonstrate that AMP administered directly to the spinal cord can reverse the secondary mechanical hyperalgesia characteristic of the intradermal capsaicin model of inflammatory pain. The specific adenosine A(1) receptor antagonist 8-cyclopentyl-1,3-dimethylxanthine (CPT) inhibits the antihyperalgesia produced by AMP. This research introduces a novel microprobe that can be used as an adjunct sampling technique to microdialysis and push-pull cannulas. Furthermore, we conclude that AMP is converted to adenosine in the dorsal horn of the spinal cord by ecto-5'-nucleotidase and subsequently may be one source of adenosine, acting through adenosine A(1) receptors in the dorsal horn of the spinal cord, which produce antihyperalgesia.

Ultrastructural localization of full-length trkB immunoreactivity in rat hippocampus suggests multiple roles in modulating activity-dependent synaptic plasticity

Neurotrophins acting at the trkB receptor have been shown to be important modulators of activity-dependent plasticity in the hippocampus, but the mechanisms underlying these effects are not yet well understood. To identify the cellular and subcellular targets of trkB ligands in the adult rat hippocampal formation, full-length trkB receptor immunoreactivity (trkB-IR) was localized using electron microscopy. trkB-IR was present in the glutamatergic pyramidal and granule cells. Labeling in these neurons appeared as discrete clusters and was primarily in axons, excitatory-type axon terminals, and dendritic spines and to a lesser extent in somata and dendritic shafts. trkB-IR was commonly found on the plasma membrane of dendritic spines, whereas in other subcellular regions trkB-IR was often intracellular. Labeling was strikingly dense within axon initial segments, suggesting extensive receptor trafficking. trkB-IR was not confined to pyramidal and granule cells. Dense trkB-IR was found in occasional interneuron axon initial segments, some axon terminals forming inhibitory-type synapses onto somata and dendritic shafts, and excitatory-type terminals likely to originate extrahippocampally. This suggests that trkB is contained in some GABAergic interneurons, neuromodulatory (e.g., cholinergic, dopaminergic, and noradrenergic) afferents, and/or glutamatergic afferents. These data indicate that full-length trkB receptor activation may modulate glutamatergic pathways of the trisynaptic circuit both presynaptically at axon terminals and initial segments and postsynaptically at dendritic spines and shafts. Signaling via catalytic trkB may also presynaptically affect inhibitory and modulatory neurons. A pan-trkB antibody labeled the same neuronal populations as the full-length-specific trkB antiserum, but the labels differed in density at various subcellular sites. These findings provide an ultrastructural foundation for further examining the mechanisms through which neurotrophins acting at trkB receptors contribute to synaptic plasticity.

Recombinant BDNF rescues deficits in basal synaptic transmission and hippocampal LTP in BDNF knockout mice

Brain-derived neurotrophic factor (BDNF) is expressed at high levels in hippocampal neurons, and its expression is modulated by neural activity. Knockout mice can be used to study the roles of molecules like BDNF in synaptic plasticity with more molecular specificity than is possible using pharmacological approaches. Because in conventional knockouts the disrupted gene product is absent in all tissues throughout the life of the animal, developmental effects may complicate the interpretation of deficits in the adult. Rescue experiments can help to distinguish between developmental and acute requirements for the missing gene product. We here demonstrate that treatment of hippocampal slices from BDNF knockout mice with recombinant BDNF completely reverses deficits in long-term potentiation and significantly improves deficits in basal synaptic transmission at the Schaffer collateral-CA1 synapse. Thus, BDNF has an acute role in hippocampal synaptic function.

Microbiologic assessment of the transabdominal ultrasound transducer head

The objectives of this study were to determine (1) the rate of bacterial isolation from the abdomen of women having obstetric ultrasonography, (2) the rate of bacterial transmission to the transducer head, and (3) the eradication rate after routine wiping of the transducer head. A total of 191 obstetric patients participated in this study. At the start of each day, the transducer head and the coupling gel were cultured. Aerobic cultures were obtained from each patient's periumbilical and suprapubic areas before the transabdominal scan and from the transducer head before and after wiping off the gel with a dry cloth. Daily transducer head and gel cultures were negative. Of the abdominal skin cultures, 175 (92%) were positive; 35 (18%) were positive for serious organisms, and 140 (74%) were positive for organisms of low virulence. Sixty percent of the transducer head cultures from women with abdominal skin pathogens were positive before the gel was wiped off. None of the cultures from the transducer head were positive after removal of the gel. We conclude that many women carry potentially virulent pathogens on the abdominal skin and that transmission of these organisms to the transducer head commonly occurs. Physical removal of the gel from the transducer head effectively eradicates these microorganisms, minimizing patient-to-patient transmission.

Nerve growth factor and a fibroblast growth factor-like neurotrophic activity in cerebrospinal fluid of brain injured human patients

We report here the presence of nerve growth factor (NGF) in the cerebrospinal fluid (CSF) of some brain-injured human patients soon after injury. The NGF was quantified against a recombinant human NGF standard in a two-site enzyme-linked immunoabsorbent assay using antibodies against murine B NGF. None of the samples collected more than 2 days after injury contained detectable levels of NGF. When the CSF was assayed for the ability to promote neurite outgrowth from PC12 cells, neurite outgrowth was reduced, but not completely blocked, by antibodies to B NGF, suggesting that there were other biologically active factors present. Fibroblast growth factor (FGF) also promotes neurite outgrowth in PC12 cells. In an initial screening for the presence of FGF, we employed PC12 cells and NR119 cells, PC12 variants in which recombinant human B NGF, but not recombinant human basic FGF, promotes neurite outgrowth. CSF from brain injury patients promoted greater neurite outgrowth from PC12 cells than from NR119 cells, suggesting that some of the biological activity associated with the injury CSF may be due a FGF. This possibility is further supported by the observation that the biological activity of the injury CSF significantly reduced by batch absorption with heparin Sepharose, suggesting the presence of a heparin binding neurotrophic factor. Neurotrophic factors appear in CSF as a consequence of diverse types of brain injury, including head trauma, intracerebral hemorrhage and subarachnoid hemorrhage. The appearance of these factors may reflect important common elements in the complex series of cellular changes occurring in response to acute brain injury.

Neurotrophin expression in rat hippocampal slices: a stimulus paradigm inducing LTP in CA1 evokes increases in BDNF and NT-3 mRNAs

We report that stimulation inducing long-term potentiation (LTP) in the CA1 pyramidal cell layer of the hippocampus evokes significant increases in both BDNF and NT-3 mRNAs in CA1 neurons. No changes in BDNF or NT-3 mRNA levels were seen in the nonstimulated regions of the pyramidal cell layer or the dentate. No change was seen in the levels of NGF mRNA at the time point examined. These results suggest that relatively normal levels of activity may regulate region-specific neurotrophin levels in the hippocampus. Given that known effects of NGF (and presumably of BDNF and NT-3) include elevation of neurotransmitter levels, elevation of sodium channels, and promotion of axonal terminal sprouting, activity-associated changes in neurotrophin levels may play a role in regulating neural connections in the adult as well as the developing nervous system.

Nerve growth factor receptor expression in the young and adult rat olfactory system

Nerve growth factor (NGF) and its receptor (NGFR) are proteins that have a role in the normal development and survival of neurons in the peripheral and central nervous systems. During development, NGF is necessary for outgrowth of axons and establishment of synapses, and NGFR is the transmembrane protein that binds NGF and brings it into the cell. NGF and NGFR expression in the rat olfactory system have been studied previously, and age differences in NGFR are explored further in this study, using immunocytochemistry and immunoelectron microscopy to determine the changes in two different ages: postnatal day 5 and the adult. Dramatic differences were found in the distribution of NGFR immunoreactivity in the olfactory system of each of the two ages studied. Electron microscopy revealed that glial cells were responsible for this immunoreactivity.

Expression of nerve growth factor (NGF) receptors in the developing inner ear of chick and rat

The expression of nerve growth factor receptors (NGFRs) was studied in the developing inner ear with in situ hybridization in chick embryos and with immunocytochemistry in rat embryos to determine sites of possible functions of NGF or NGF-like molecules in inner ear development. NGFR expression in the chick otocyst and acoustic ganglion is compared with epithelial differentiation and the onset of afferent innervation as determined with fluorescent carbocyanine tracers. In the inner ear of the chick embryo, NGFR mRNA expression shows an alternating pattern in mesenchymal and epithelial tissues. NGFR mRNA is heavily expressed in the mesenchyme surrounding the otocyst (E2-3), ceases at E3-5, and reappears in a thin layer of mesenchymal cells surrounding the membraneous epithelia (E5-13). In the otocyst epithelium, NGFR mRNA expression develops in one anterior and one posterior focus at E3-4.5. NGFR mRNA is expressed in the primordia of the ampullary cristae (E5-7) and possibly the anlage of the utricle; label transiently concentrates in the planum semilunatum of the cristae ampullares and in superior portions of the semicircular canals at E9, but is not seen in differentiating hair cells. In the acoustic ganglion, NGFR mRNA expression begins at E4; at the same time, the first peripheral acoustic nerve processes penetrate the otic epithelium (E4-4.5). The acoustic ganglia remain weakly NGFR mRNA-labeled in the posthatch animal. In the rat embryo, NGFR immunoreactivity is present in the auditory placode at E9, in the periotic mesenchyme at E9-10, and in the medial half of the otocyst at E10-11. At E12, epithelial NGFR expression becomes restricted anteriorly and posteriorly in a pattern similar to that of the chick otocyst and ceases at E13. NGFR immunoreactivity appears transiently in pillar cells of the cochlea in the third week of gestation. NGFR and NGFR mRNA is expressed after E11 in the acoustic ganglia. While NGFR transcripts are expressed in the cochlear ganglion cell bodies, NGFR protein becomes restricted to neuronal processes by the third week of gestation. The vestibular, but not the cochlear (spiral) ganglia remain NGFR-labeled in the adult rat. Onset of NGFR mRNA expression in the acoustic ganglion during the period of afferent fiber ingrowth into the otocyst epithelium is consistent with the hypothesis that NGF-like molecules may have a neurotrophic function for acoustic ganglion cells. Transient expression of NGFRs in secretory cells of the vestibular endorgan and pillar cells in the organ of Corti implicate a role for neurotrophins in the differentiation of these epithelial cell types.

Universal precautions are not universally followed

Adherence to universal blood and body fluid precautions was studied in surgical patient care areas of a university hospital in an effort to identify potentially hazardous health care personnel practices. Surgical teams of an 18-unit operating room, three surgical ward patient care teams, and patient care personnel in a 16-bed surgical intensive care unit were observed during routine patient care activities before (study 1) and after (study 2) specific educational programs were held to improve universal precaution compliance. Overall, infractions occurred in 57% of 549 observed procedures in study 1 and in 58% of 616 observed procedures in study 2. In study 1, infractions occurred in 75% of operating room procedures, 30% of surgical ward procedures, and 75% of surgical intensive care unit procedures. Study 2 procedure infraction rates were 81%, 32%, and 40%, respectively. Only surgical intensive care unit compliance significantly improved. Noncompliance with universal precautions occurs frequently during the care of patients who have undergone surgery, with the type of infraction and specific offender varying according to patient locale. These violations appear unamenable to one-time educational efforts. Substantial overall improvement may arise from ongoing educational programs directed at specific personnel who care for patients who have undergone surgery.

Thermoregulation in hypergravity-acclimated rats

To determine the effect of hypergravity acclimation on thermoregulation, core temperature (Tc), tail temperature (Tt), and O2 consumption (VO2) were measured in control rats (raised at 1 G) and in rats acclimated to 2.1 G. When the animals were exposed to a low ambient temperature of 9 degrees C, concurrently with a hypergravic field of 2.1 G, Tc of rats raised at 1 G fell markedly by approximately 6 degrees C (to 30.8 +/- 0.6 degrees C) while that of the rats raised at 2.1 G remained relatively constant (falling only approximately 1 degree C to 36.4 +/- 0.3 degrees C). Thus prior acclimation to a 2.1-G field enabled rats to maintain Tc when cold exposed in a 2.1-G field. To maintain Tc, thermogenic mechanisms were successfully activated in the 2.1-G-acclimated rats as shown by measurements of VO2. In contrast, VO2 measurements showed that rats reared at 1 G and then cold exposed at 2.1 G did not activate thermogenic mechanisms sufficiently to prevent a fall in Tc. In other experiments, rats acclimated to either 1 or 2.1 G were found to lack the ability to maintain their Tc when exposed to a 5.8-G field or when exposed to prolonged cold exposure at 1 G. Results are interpreted as showing that when placed in a 2.1-G field, rats acclimated to 2.1 G can more closely maintain their Tc near 37 degrees C when cold exposed than can rats acclimated to 1 G. However, this enhanced regulatory ability of 2.1-G-acclimated rats over 1.0-G-acclimated rats is restricted to 2.1-G fields and is not observed in 1.0- and 5.8-G fields.

Hypnotic susceptibility and performance on various attention-specific cognitive tasks

We conducted two experiments to investigate cognitive performance as related to level of hypnotic susceptibility. In Experiment 1 time-to-location of a target in a visual search task was assessed. For this task the letter Z was embedded either within straight-form or round-form letters. Results indicated that high-hypnotic-susceptibility subjects (highs) were significantly faster than low-susceptibility-subjects (lows) in locating the embedded letter. Experiment 2 investigated performance on single- and double-digit arithmetic (addition) problems as a function of hypnotic susceptibility level. Subjects were presented with arithmetic problems and were asked to complete them within a 60-s time period. Highs completed a significantly greater number of double-digit problems but not single-digit problems within this time frame than did lows. The results of the two experiments are explained in terms of the application of differing strategies or operations by highs and lows in the performance of cognitive tasks.