Communicating about HPV in the context of head and neck cancer: A systematic review of quantitative studies

OBJECTIVE

Rising incidence of HPV-positive head and neck cancers (HPV-HNC) means HPV infection is increasingly relevant to patient-provider consultations. We performed a systematic review to examine, in the context of patient-provider HNC consultations: discussions about HPV, attitudes towards discussing HPV and information needs.

METHODS

We searched Embase, PsychINFO, and CINAHL + for studies to August 2018. Eligible studies included: HNC healthcare professionals (HCPs) and/or HNC patients investigated HNC patient-provider communication about HPV.

RESULTS

Ten studies were identified: six including HCPs and four including HNC patients. HCPs varied in confidence in HPV discussions, which was related to their HPV knowledge. Both HCPs and patients acknowledged the need for reliable HPV information. Factors which facilitated HPV discussions included accessible HPV information for patients and HCPs and good HPV knowledge among HCPs. Barriers included the perception, among HCPs, that HPV was a challenging topic to discuss with patients.

CONCLUSIONS

Information deficits, communication challenges and barriers to discussing HPV were identified in HNC patient-provider consultations.

PRACTICE IMPLICATIONS

Appropriate HPV information is needed for HCPs and patients. Professional development initiatives which increase HCPs' HPV knowledge and build their communication skills would be valuable.

Physical after-effects of colposcopy and related procedures, and their inter-relationship with psychological distress: a longitudinal survey

OBJECTIVE

To estimate prevalence of post-colposcopy physical after-effects and investigate associations between these and subsequent psychological distress.

DESIGN

Longitudinal survey.

SETTING

Two hospital-based colposcopy clinics.

POPULATION

Women with abnormal cytology who underwent colposcopy (±related procedures).

METHODS

Questionnaires were mailed to women 4, 8 and 12 months post-colposcopy. Details of physical after-effects (pain, bleeding and discharge) experienced post-colposcopy were collected at 4 months. Colposcopy-specific distress was measured using the Process Outcome-Specific Measure at all time-points. Linear mixed-effects regression was used to identify associations between physical after-effects and distress over 12 months, adjusting for socio-demographic and clinical variables.

MAIN OUTCOME MEASURES

Prevalence of post-colposcopy physical after-effects. Associations between the presence of any physical after-effects, awareness of after-effects, and number of after-effects and distress.

RESULTS

Five-hundred and eighty-four women were recruited (response rate = 73, 59 and 52% at 4, 8 and 12 months, respectively). Eighty-two percent of women reported one or more physical after-effect(s). Multiple physical after-effects were common (two after-effects = 25%; three after-effects = 25%). Psychological distress scores declined significantly over time. In adjusted analyses, women who experienced all three physical after-effects had on average a 4.58 (95% CI: 1.10-8.05) higher distress scored than those who experienced no after-effects. Women who were unaware of the possibility of experiencing after-effects scored significantly higher for distress during follow-up.

CONCLUSIONS

The prevalence of physical after-effects of colposcopy and related procedures is high. The novel findings of inter-relationships between awareness of the possibility of after-effects and experiencing multiple after-effects, and post-colposcopy distress may be relevant to the development of interventions to alleviate post-colposcopy distress.

TWEETABLE ABSTRACT

Experiencing multiple physical after-effects of colposcopy is associated with psychological distress.

Comparison of pharmacological and non-pharmacological interventions to prevent delirium in critically ill patients: a protocol for a systematic review incorporating network meta-analyses

BACKGROUND

Delirium is characterized by acute changes in mental status including inattention, disorganized thinking, and altered level of consciousness, and is highly prevalent in critically ill adults. Delirium has adverse consequences for both patients and the healthcare system; however, at this time, no effective treatment exists. The identification of effective prevention strategies is therefore a clinical and research imperative. An important limitation of previous reviews of delirium prevention is that interventions were considered in isolation and only direct evidence was used. Our systematic review will synthesize all existing data using network meta-analysis, a powerful statistical approach that enables synthesis of both direct and indirect evidence.

METHODS

We will search Ovid MEDLINE, CINAHL, Embase, PsycINFO, and Web of Science from 1980 to March 2016. We will search the PROSPERO registry for protocols and the Cochrane Library for published systematic reviews. We will examine reference lists of pertinent reviews and search grey literature and the International Clinical Trials Registry Platform for unpublished studies and ongoing trials. We will include randomized and quasi-randomized trials of critically ill adults evaluating any pharmacological, non-pharmacological, or multi-component intervention for delirium prevention, administered in or prior to (i.e., peri-operatively) transfer to the ICU. Two authors will independently screen search results and extract data from eligible studies. Risk of bias assessments will be completed on all included studies. To inform our network meta-analysis, we will first conduct conventional pair-wise meta-analyses for primary and secondary outcomes using random-effects models. We will generate our network meta-analysis using a Bayesian framework, assuming a common heterogeneity parameter across all comparisons, and accounting for correlations in multi-arm studies. We will perform analyses using WinBUGS software.

DISCUSSION

This systematic review will address the existing knowledge gap regarding best practices for delirium prevention in critically ill adults by synthesizing evidence from trials of pharmacological, non-pharmacological, and multi-component interventions administered in or prior to transfer to the ICU. Use of network meta-analysis will clarify which delirium prevention strategies are most effective in improving clinical outcomes while causing least harm. The network meta-analysis is a novel approach and will provide knowledge users and decision makers with comparisons of multiple interventions of delirium prevention strategies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016036313.

Triage of LSIL/ASC-US with p16/Ki-67 dual staining and human papillomavirus testing: a 2-year prospective study

OBJECTIVE

To investigate human papillomavirus (HPV) DNA testing and p16/Ki-67 staining for detecting cervical intraepithelial grade 2 or worse (CIN2+) and CIN3 in women referred to colposcopy with minor abnormal cervical cytology low-grade squamous intraepithelial lesions (LSIL) and atypical squamous cells of undermined significance (ASC-US). The clinical performance of both tests was evaluated as stand-alone tests and combined, for detection CIN2+ and CIN3 over 2 years.

METHODS

ThinPrep(®) liquid-based cytology (LBC) specimens were collected from 1349 women with repeat LSIL or ASC-US. HPV DNA was performed using Hybrid Capture. Where adequate material remained (n = 471), p16/Ki-67 overexpression was assessed. Clinical performance for detection of histologically diagnosed CIN2+ and CIN3 was calculated.

RESULTS

Approximately 62.2% of the population were positive for HPV DNA, and 30.4% were positive for p16/Ki-67. p16/Ki-67 showed no significant difference in positivity between LSIL and ASC-US referrals (34.3% versus 28.6%; P = 0.189). Women under 30 years had a higher rate of p16/Ki-67 compared to those over 30 years (36.0% versus 26.6%; P = 0.029). Overall HPV DNA testing produced a high sensitivity for detection of CIN3 of 95.8% compared to 79.2% for p16/Ki-67. In contrast, p16/Ki-67 expression offered a higher specificity, 75.2% versus 40.4% for detection of CIN3. Combining p16/Ki-67 with HPV DNA improved the accuracy in distinguishing between CIN3 and <CIN3. The absolute risk of CIN3 increased from 15.6% in women who were HPV DNA positive to 27% in women positive for HPV DNA and p16/Ki-67. Those negative for HPV DNA and p16/Ki-67 had a low risk of 1.2% of CIN3.

CONCLUSION

The addition of p16/Ki-67 to HPV DNA testing leads to a more accurate stratification of CIN in women presenting with minor cytological abnormalities.

Adverse psychological outcomes following colposcopy and related procedures: a systematic review

BACKGROUND

Although colposcopy is the leading follow-up option for women with abnormal cervical cytology, little is known about its psychological consequences.

OBJECTIVES

We performed a systematic review to examine: (1) what, if any, are the adverse psychological outcomes following colposcopy and related procedures; (2) what are the predictors of adverse psychological outcomes post-colposcopy; and (3) what happens to these outcomes over time.

SEARCH STRATEGY

Five electronic databases (PubMed, PsychINFO, CINAHL, Web of Science, Scopus) were searched for studies published in English between January 1986 and February 2014.

SELECTION CRITERIA

Eligible studies assessed psychological wellbeing at one or more time-points post-colposcopy.

DATA COLLECTION AND ANALYSIS

Two reviewers independently screened titles and abstracts. Full texts of potentially eligible papers were reviewed. Data were abstracted from, and a quality appraisal performed of, eligible papers.

MAIN RESULTS

Twenty-three papers reporting 16 studies were eligible. Colposcopy and related procedures can lead to adverse psychological outcomes, particularly anxiety. Ten studies investigated predictors of adverse psychological outcomes; management type and treatment had no impact on this. Seven studies investigated temporal trends in psychological outcomes post-colposcopy; findings were mixed, especially in relation to anxiety and distress. Studies were methodologically heterogeneous.

CONCLUSIONS

Follow-up investigations and procedures for abnormal cervical cytology can cause adverse psychological outcomes among women. However, little is known about the predictors of these outcomes or how long they persist. There is a need for a more standardised approach to the examination of the psychological impact of colposcopy, especially longer-term outcomes.

TWEETABLE ABSTRACT

Follow-up investigations for abnormal cervical cytology can cause adverse psychological outcome among women.

Activation of colo-rectal high-threshold afferent nerves by Interleukin-2 is tetrodotoxin-sensitive and upregulated in a mouse model of chronic visceral hypersensitivity

BACKGROUND

Chronic visceral pain is a defining feature of irritable bowel syndrome (IBS). IBS patients often show alterations in innate and adaptive immune function which may contribute to symptoms. Immune mediators are known to modulate the activity of viscero-sensory afferent nerves, but the focus has been on the innate immune system. Interleukin-2 (IL-2) is primarily associated with adaptive immune responses but its effects on colo-rectal afferent function in health or disease are unknown.

METHODS

Myeloperoxidase (MPO) activity determined the extent of inflammation in health, acute trinitrobenzene-sulfonic acid (TNBS) colitis, and in our post-TNBS colitis model of chronic visceral hypersensitivity (CVH). The functional effects of IL-2 on high-threshold colo-rectal afferents and the expression of IL-2R and NaV 1.7 mRNA in colo-rectal dorsal root ganglia (DRG) neurons were compared between healthy and CVH mice.

KEY RESULTS

MPO activity was increased during acute colitis, but subsided to levels comparable to health in CVH mice. IL-2 caused direct excitation of colo-rectal afferents that was blocked by tetrodotoxin. IL-2 did not affect afferent mechanosensitivity in health or CVH. However, an increased proportion of afferents responded directly to IL-2 in CVH mice compared with controls (73% vs 33%; p < 0.05), and the abundance of IL-2R and NaV 1.7 mRNA was increased 3.5- and 2-fold (p < 0.001 for both) in colo-rectal DRG neurons.

CONCLUSIONS & INFERENCES

IL-2, an immune mediator from the adaptive arm of the immune response, affects colo-rectal afferent function, indicating these effects are not restricted to innate immune mediators. Colo-rectal afferent sensitivity to IL-2 is increased long after healing from inflammation.

T helper type 2-polarized invariant natural killer T cells reduce disease severity in acute intra-abdominal sepsis

Sepsis is characterized by a severe systemic inflammatory response to infection that is associated with high morbidity and mortality despite optimal care. Invariant natural killer T (iNK T) cells are potent regulatory lymphocytes that can produce pro- and/or anti-inflammatory cytokines, thus shaping the course and nature of immune responses; however, little is known about their role in sepsis. We demonstrate here that patients with sepsis/severe sepsis have significantly elevated proportions of iNK T cells in their peripheral blood (as a percentage of their circulating T cells) compared to non-septic patients. We therefore investigated the role of iNK T cells in a mouse model of intra-abdominal sepsis (IAS). Our data show that iNK T cells are pathogenic in IAS, and that T helper type 2 (Th2) polarization of iNK T cells using the synthetic glycolipid OCH significantly reduces mortality from IAS. This reduction in mortality is associated with the systemic elevation of the anti-inflammatory cytokine interleukin (IL)-13 and reduction of several proinflammatory cytokines within the spleen, notably interleukin (IL)-17. Finally, we show that treatment of sepsis with OCH in mice is accompanied by significantly reduced apoptosis of splenic T and B lymphocytes and macrophages, but not natural killer cells. We propose that modulation of iNK T cell responses towards a Th2 phenotype may be an effective therapeutic strategy in early sepsis.

'I don't care whether it's HPV or ABC, I just want to know if I have cancer.' Factors influencing women's emotional responses to undergoing human papillomavirus testing in routine management in cervical screening: a qualitative study

OBJECTIVE

To explore emotional responses, and predictors of negative reactions, among women undergoing human papillomavirus (HPV) tests in routine clinical practice.

DESIGN

Exploratory qualitative interview study.

SETTING

A large busy colposcopy clinic in a Dublin hospital.

SAMPLE

Twenty-seven women who had had an HPV DNA test in the previous 6 months following one or more low-grade cytology tests or treatment for cervical intraepithelial neoplasia (CIN).

METHODS

In-depth semi-structured interviews were conducted. Interview transcripts were analysed using a thematic approach (Framework Analysis).

MAIN OUTCOME MEASURES

Women's emotional responses and predictors of negative emotional reactions.

RESULTS

For most women, having a test for high-risk HPV types generated little negative or positive emotional impact. Adverse emotional responses related to HPV infection rather than testing. Factors that influenced whether women experienced negative emotional responses were: concerns over abnormal cytology or diagnosis of CIN; HPV knowledge; awareness of HPV being sexually transmitted; awareness of HPV prevalence; and HPV information needs. Women's concerns about abnormal cytology/CIN dominated all other issues.

CONCLUSIONS

These qualitative data suggest that in the context of follow up of abnormal cytology or treatment for CIN, the emotional impact of HPV testing may be modest: women's primary concerns at this time relate to abnormal cytology/CIN.

Linaclotide inhibits colonic nociceptors and relieves abdominal pain via guanylate cyclase-C and extracellular cyclic guanosine 3',5'-monophosphate

BACKGROUND & AIMS

Linaclotide is a minimally absorbed agonist of guanylate cyclase-C (GUCY2C or GC-C) that reduces symptoms associated with irritable bowel syndrome with constipation (IBS-C). Little is known about the mechanism by which linaclotide reduces abdominal pain in patients with IBS-C.

METHODS

We determined the effects of linaclotide on colonic sensory afferents in healthy mice and those with chronic visceral hypersensitivity. We assessed pain transmission by measuring activation of dorsal horn neurons in the spinal cord in response to noxious colorectal distention. Levels of Gucy2c messenger RNA were measured in tissues from mice using quantitative reverse transcription polymerase chain reaction and in situ hybridization. We used human intestinal cell lines to measure release of cyclic guanosine-3',5'-monophosphate (cGMP) by linaclotide. We performed a post-hoc analysis of data from a phase III, double-blind, parallel-group study in which 805 patients with IBS-C were randomly assigned to groups given an oral placebo or 290 μg linaclotide once daily for 26 weeks. We quantified changes in IBS-C symptoms, including abdominal pain.

RESULTS

In mice, linaclotide inhibited colonic nociceptors with greater efficacy during chronic visceral hypersensitivity. Intra-colonic administration of linaclotide reduced signaling of noxious colorectal distention to the spinal cord. The colonic mucosa, but not neurons, was found to express linaclotide's target, GC-C. The downstream effector of GC-C, cGMP, was released after administration of linaclotide and also inhibited nociceptors. The effects of linaclotide were lost in Gucy2c(-/-) mice and prevented by inhibiting cGMP transporters or removing the mucosa. During 26 weeks of linaclotide administration, a significantly greater percentage of patients (70%) had at least a 30% reduction in abdominal pain compared with patients given placebo (50%).

CONCLUSIONS

We have identified an analgesic mechanism of linaclotide: it activates GC-C expressed on mucosal epithelial cells, resulting in the production and release of cGMP. This extracellular cGMP acts on and inhibits nociceptors, thereby reducing nociception. We also found that linaclotide reduces chronic abdominal pain in patients with IBS-C.

The ion channel TRPA1 is required for normal mechanosensation and is modulated by algesic stimuli

BACKGROUND & AIMS

The transient receptor potential (TRP) channel family includes transducers of mechanical and chemical stimuli for visceral sensory neurons. TRP ankyrin 1 (TRPA1) is implicated in inflammatory pain; it interacts with G-protein-coupled receptors, but little is known about its role in the gastrointestinal (GI) tract. Sensory information from the GI tract is conducted via 5 afferent subtypes along 3 pathways.

METHODS

Nodose and dorsal root ganglia whose neurons innnervate 3 different regions of the GI tract were analyzed from wild-type and TRPA1(-/-) mice using quantitative reverse-transcription polymerase chain reaction, retrograde labeling, and in situ hybridization. Distal colon sections were analyzed by immunohistochemistry. In vitro electrophysiology and pharmacology studies were performed, and colorectal distension and visceromotor responses were measured. Colitis was induced by administration of trinitrobenzene sulphonic acid.

RESULTS

TRPA1 is required for normal mechano- and chemosensory function in specific subsets of vagal, splanchnic, and pelvic afferents. The behavioral responses to noxious colonic distension were substantially reduced in TRPA1(-/-) mice. TRPA1 agonists caused mechanical hypersensitivity, which increased in mice with colitis. Colonic afferents were activated by bradykinin and capsaicin, which mimic effects of tissue damage; wild-type and TRPA1(-/-) mice had similar direct responses to these 2 stimuli. After activation by bradykinin, wild-type afferents had increased mechanosensitivity, whereas, after capsaicin exposure, mechanosensitivity was reduced: these changes were absent in TRPA1(-/-) mice. No interaction between protease-activated receptor-2 and TRPA1 was evident.

CONCLUSIONS

These findings demonstrate a previously unrecognized role for TRPA1 in normal and inflamed mechanosensory function and nociception within the viscera.

Post-inflammatory colonic afferent sensitisation: different subtypes, different pathways and different time courses

OBJECTIVE

Intestinal infection evokes hypersensitivity in a subgroup of patients with irritable bowel syndrome (IBS) long after healing of the initial injury. Trinitrobenzene sulfonic acid (TNBS)-induced colitis in rodents likewise results in delayed maintained hypersensitivity, regarded as a model of some aspects of IBS. The colon and rectum have a complex sensory innervation, comprising five classes of mechanosensitive afferents in the splanchnic and pelvic nerves. Their plasticity may hold the key to underlying mechanisms in IBS. Our aim was therefore to determine the contribution of each afferent class in each pathway towards post-inflammatory visceral hypersensitivity.

DESIGN

TNBS was administered rectally and mice were studied after 7 (acute) or 28 (recovery) days. In vitro preparations of mouse colorectum with attached pelvic or splanchnic nerves were used to examine the mechanosensitivity of individual colonic afferents.

RESULTS

Mild inflammation of the colon was evident acutely which was absent at the recovery stage. TNBS treatment did not alter proportions of the five afferent classes between treatment groups. In pelvic afferents little or no difference in response to mechanical stimuli was apparent in any class between control and acute mice. However, major increases in mechanosensitivity were recorded from serosal afferents in mice after recovery, while responses from other subtypes were unchanged. Both serosal and mesenteric splanchnic afferents were hypersensitive at both acute and recovery stages.

CONCLUSIONS

Colonic afferents with high mechanosensory thresholds contribute to inflammatory hypersensitivity, but not those with low thresholds. Pelvic afferents become involved mainly following recovery from inflammation, whereas splanchnic afferents are implicated during both inflammation and recovery.

Reentrant condensation of proteins in solution induced by multivalent counterions

Negatively charged globular proteins in solution undergo a condensation upon adding trivalent counterions between two critical concentrations C and C, C <C. This reentrant condensation behavior above C is caused by short-ranged electrostatic interactions between multivalent cations and acidic residues, mechanistically different from the case of DNA. Small-angle x-ray scattering indicates a short-ranged attraction between counterion-bound proteins near C and C. Monte Carlo simulations (under these strong electrostatic coupling conditions) support an effective inversion of charge on surface side chains through binding of the multivalent counterions.

Structure, rheology and shear alignment of Pluronic block copolymer mixtures

The structure and flow behaviour of binary mixtures of Pluronic block copolymers P85 and P123 is investigated by small-angle scattering, rheometry and mobility tests. Micelle dimensions are probed by dynamic light scattering. The micelle hydrodynamic radius for the 50/50 mixture is larger than that for either P85 or P123 alone, due to the formation of mixed micelles with a higher association number. The phase diagram for 50/50 mixtures contains regions of cubic and hexagonal phases similar to those for the parent homopolymers, however the region of stability of the cubic phase is enhanced at low temperature and concentrations above 40 wt%. This is ascribed to favourable packing of the mixed micelles containing core blocks with two different chain lengths, but similar corona chain lengths. The shear flow alignment of face-centred cubic and hexagonal phases is probed by in situ small-angle X-ray or neutron scattering with simultaneous rheology. The hexagonal phase can be aligned using steady shear in a Couette geometry, however the high modulus cubic phase cannot be aligned well in this way. This requires the application of oscillatory shear or compression.

Transient receptor potential vanilloid 4 mediates protease activated receptor 2-induced sensitization of colonic afferent nerves and visceral hyperalgesia

Protease-activated receptor (PAR(2)) is expressed by nociceptive neurons and activated during inflammation by proteases from mast cells, the intestinal lumen, and the circulation. Agonists of PAR(2) cause hyperexcitability of intestinal sensory neurons and hyperalgesia to distensive stimuli by unknown mechanisms. We evaluated the role of the transient receptor potential vanilloid 4 (TRPV4) in PAR(2)-induced mechanical hyperalgesia of the mouse colon. Colonic sensory neurons, identified by retrograde tracing, expressed immunoreactive TRPV4, PAR(2), and calcitonin gene-related peptide and are thus implicated in nociception. To assess nociception, visceromotor responses (VMR) to colorectal distension (CRD) were measured by electromyography of abdominal muscles. In TRPV4(+/+) mice, intraluminal PAR(2) activating peptide (PAR(2)-AP) exacerbated VMR to graded CRD from 6-24 h, indicative of mechanical hyperalgesia. PAR(2)-induced hyperalgesia was not observed in TRPV4(-/-) mice. PAR(2)-AP evoked discharge of action potentials from colonic afferent neurons in TRPV4(+/+) mice, but not from TRPV4(-/-) mice. The TRPV4 agonists 5',6'-epoxyeicosatrienoic acid and 4alpha-phorbol 12,13-didecanoate stimulated discharge of action potentials in colonic afferent fibers and enhanced current responses recorded from retrogradely labeled colonic dorsal root ganglia neurons, confirming expression of functional TRPV4. PAR(2)-AP enhanced these responses, indicating sensitization of TRPV4. Thus TRPV4 is expressed by primary spinal afferent neurons innervating the colon. Activation of PAR(2) increases currents in these neurons, evokes discharge of action potentials from colonic afferent fibers, and induces mechanical hyperalgesia. These responses require the presence of functional TRPV4. Therefore, TRPV4 is required for PAR(2)-induced mechanical hyperalgesia and excitation of colonic afferent neurons.

Acid sensing ion channels 2 and 3 are required for inhibition of visceral nociceptors by benzamil

The Deg/ENaC family of ion channels, including ASIC1, 2 and 3, are candidate mechanotransducers in visceral and somatic sensory neurons, although each channel may play a different role in different sensory pathways. Here we determined which distinct populations of visceral sensory neurons are sensitive to the non-selective Deg/ENaC blocker benzamil, and which ASIC channels are targets for benzamil by studying its actions in knockout mice. Single afferent fiber recordings were made in vitro from mouse high threshold colonic thoracolumbar splanchnic afferents and low threshold gastroesophageal vagal afferents. mRNA expression of ASIC subtypes was compared between colonic and gastroesophageal afferents by quantitative RT-PCR of transcripts following laser capture microdissection of retrogradely labeled cell bodies. Mechanosensitivity of colonic afferents was potently reduced by benzamil (10(-6)-3 x 10(-4)M), whereas gastroesophageal afferents were marginally inhibited. Inhibition of colonic afferent mechanosensitivity by benzamil was markedly diminished in ASIC2-/- and ASIC3-/- mice, but unchanged in ASIC1a-/-. Therefore ASIC2 and 3 are targets for benzamil to inhibit colonic afferent mechanosensitivity. Conversely, gastroesophageal afferents are less sensitive to benzamil, and its action depends less on ASIC expression. mRNA for ASIC3 showed higher and ASIC1a showed lower relative expression in colonic afferents from thoracolumbar dorsal root ganglia than in gastric afferents from nodose (vagal) ganglia. These data indicate that ASICs on colonic afferents present distinct pharmacological targets for visceral pain.

Involvement of metabotropic glutamate 5 receptor in visceral pain

Metabotropic glutamate 5 receptor (mGluR5) antagonists are effective in animal models of inflammatory and neuropathic pain. The involvement of mGluR5 in visceral pain pathways from the gastrointestinal tract is as yet unknown. We evaluated effects of mGluR5 antagonists on the colorectal distension (CRD)-evoked visceromotor (VMR) and cardiovascular responses in conscious rats, and on mechanosensory responses of mouse colorectal afferents in vitro. Sprague-Dawley rats were subjected to repeated, isobaric CRD (12 x 80 mmHg, for 30s with 5 min intervals). The VMR and cardiovascular responses to CRD were monitored. The mGluR5 antagonists MPEP (1-10 micromol/kg, i.v.) and MTEP (1-3 micromol/kg, i.v.) reduced the VMR to CRD dose-dependently with maximal inhibition of 52+/-8% (p<0.01) and 25+/-11% (p<0.05), respectively, without affecting colonic compliance. MPEP (10 micromol/kg, i.v.) reduced CRD-evoked increases in blood pressure and heart rate by 33+/-9% (p<0.01) and 35+/-8% (p<0.05), respectively. Single afferent recordings were made from mouse pelvic and splanchnic nerves of colorectal mechanoreceptors. Circumferential stretch (0-5 g force) elicited slowly-adapting excitation of action potentials in pelvic distension-sensitive afferents. This response was reduced 55-78% by 10 microM MTEP (p<0.05). Colonic probing (2g von Frey hair) activated serosal splanchnic afferents; their responses were reduced 50% by 10 microM MTEP (p<0.01). We conclude that mGluR5 antagonists inhibit CRD-evoked VMR and cardiovascular changes in conscious rats, through an effect, at least in part, at peripheral afferent endings. Thus, mGluR5 participates in mediating mechanically evoked visceral nociception in the gastrointestinal tract.

Gold nanoparticles decorated with oligo(ethylene glycol) thiols: protein resistance and colloidal stability

The interactions between proteins and gold colloids functionalized with protein-resistant oligo(ethylene glycol) (OEG) thiol, HS(CH2)11(OCH2CH2)6OMe (EG6OMe), in aqueous solution have been studied by small-angle X-ray scattering (SAXS) and UV-vis spectroscopy. The mean size, 2R, and the size distribution of the decorated gold colloids have been characterized by SAXS. The monolayer-protected gold colloids have no correlations due to the low volume fraction in solution and are stable in a wide range of temperatures (5-70 degrees C), pH (1.3-12.4), and ionic strength (0-1.0 M). In contrast, protein (bovine serum albumin) solutions with concentrations in the range of 60-200 mg/mL (4.6-14.5 vol %) show a pronounced correlation peak in SAXS, which results from the repulsive electrostatic interaction between charged proteins. These protein interactions show significant dependence on ionic strength, as would be expected for an electrostatic interaction (Zhang et al. J. Phys. Chem. B 2007, 111, 251). For a mixture of proteins and gold colloids, the protein-protein interaction changes little upon mixing with OEG-decorated gold colloids. In contrast, the colloid-colloid interaction is found to be strongly dependent on the protein concentration and the size of the colloid itself. Adding protein to a colloidal solution results in an attractive depletion interaction between functionalized gold colloids, and above a critical protein concentration, c*, the colloids form aggregates and flocculate. Adding salt to such mixtures enhances the depletion effect and decreases the critical protein concentration. The aggregation is a reversible process (i.e., diluting the solution leads to dissolution of aggregates). The results also indicate that the charge of the OEG self-assembled monolayer at a curved interface has a rather limited effect on the colloidal stabilization and the repulsive interaction with proteins.

Development of structural order during supercooling of a fragile oxide melt

The authors have studied the structural evolution of the fragile glass-forming liquid CaAl2O4 during supercooling from the stable liquid phase to the cold glass below Tg. The evolution is characterized by a sharpening of the first diffraction peak and a shortening of the average nearest-neighbor bond length around 1.25Tg, indicating an increase in the degree of both intermediate-range and short-range orders occurring close to the dynamical crossover temperature. The cooling curve developed a kink at this temperature, indicating a simultaneous change in thermodynamic properties.

Protein Interactions Studied by SAXS: Effect of Ionic Strength and Protein Concentration for BSA in Aqueous Solutions

We have studied a series of samples of bovine serum albumin (BSA) solutions with protein concentration, c, ranging from 2 to 500 mg/mL and ionic strength, I, from 0 to 2 M by small-angle X-ray scattering (SAXS). The scattering intensity distribution was compared to simulations using an oblate ellipsoid form factor with radii of 17 x 42 x 42 A, combined with either a screened Coulomb, repulsive structure factor, SSC(q), or an attractive square-well structure factor, SSW(q). At pH = 7, BSA is negatively charged. At low ionic strength, I < 0.3 M, the total interaction exhibits a decrease of the repulsive interaction when compared to the salt-free solution, as the net surface charge is screened, and the data can be fitted by assuming an ellipsoid form factor and screened Coulomb interaction. At moderate ionic strength (0.3-0.5 M), the interaction is rather weak, and a hard-sphere structure factor has been used to simulate the data with a higher volume fraction. Upon further increase of the ionic strength (I >or= 1.0 M), the overall interaction potential was dominated by an additional attractive potential, and the data could be successfully fitted by an ellipsoid form factor and a square-well potential model. The fit parameters, well depth and well width, indicate that the attractive potential caused by a high salt concentration is weak and long-ranged. Although the long-range, attractive potential dominated the protein interaction, no gelation or precipitation was observed in any of the samples. This is explained by the increase of a short-range, repulsive interaction between protein molecules by forming a hydration layer with increasing salt concentration. The competition between long-range, attractive and short-range, repulsive interactions accounted for the stability of concentrated BSA solution at high ionic strength.

In situSAXS studies of the morphological changes of an alumina–zirconia–silicate ceramic during its formation

Small-angle X-ray scattering is used at two energies, one either side of the zirconiumK-edge, to probe thein situformation of an alumina–zirconia–silicate ceramic. The use of energies either side of the edge allows the decomposition of information regarding the scattering from the zirconia particles from that of the glass matrix. Porod slope data show how the nanoparticles progress from being relatively isolated particles to becoming agglomerates as the pore network in the glass collapses. The shape of the agglomerates resembles the pore network of the glass at low temperature. The Guinier radii of the particles show the growth of the agglomerates past the Littleton softening point, whilst still resolving the primary particles.

Different contributions of ASIC channels 1a, 2, and 3 in gastrointestinal mechanosensory function

AIMS

Members of the acid sensing ion channel (ASIC) family are strong candidates as mechanical transducers in sensory function. The authors have shown that ASIC1a has no role in skin but a clear influence in gastrointestinal mechanotransduction. Here they investigate further ASIC1a in gut mechanoreceptors, and compare its influence with ASIC2 and ASIC3.

METHODS AND RESULTS

Expression of ASIC1a, 2, and 3 mRNA was found in vagal (nodose) and dorsal root ganglia (DRG), and was lost in mice lacking the respective genes. Recordings of different classes of splanchnic colonic afferents and vagal gastro-oesophageal afferents revealed that disruption of ASIC1a increased the mechanical sensitivity of all afferents in both locations. Disruption of ASIC2 had varied effects: increased mechanosensitivity in gastro-oesophageal mucosal endings, decreases in gastro-oesophageal tension receptors, increases in colonic serosal endings, and no change in colonic mesenteric endings. In ASIC3-/- mice, all afferent classes had markedly reduced mechanosensitivity except gastro-oesophageal mucosal receptors. Observations of gastric emptying and faecal output confirmed that increases in mechanosensitivity translate to changes in digestive function in conscious animals.

CONCLUSIONS

These data show that ASIC3 makes a critical positive contribution to mechanosensitivity in three out of four classes of visceral afferents. The presence of ASIC1a appears to provide an inhibitory contribution to the ion channel complex, whereas the role of ASIC2 differs widely across subclasses of afferents. These findings contrast sharply with the effects of ASIC1, 2, and 3 in skin, suggesting that targeting these subunits with pharmacological agents may have different and more pronounced effects on mechanosensitivity in the viscera.

On the nanostructure of radiation-amorphized zircon and pyrochlores: a small-angle x-ray scattering study

Nanoscale structural features of amorphous zircon and pyrochlore produced by self-irradiation induced amorphization have been characterized by small-angle X-ray scattering (SAXS). Electron density fluctuations were observed in the untreated samples and studied as a function of annealing temperature (up to 1300 °C). In untreated zircon, density fluctuations were found to have a characteristic length-scale of approximately 1 nanometer diameter. A clear scattering maximum develops at ∼3 nm–1 as a function of the degree of damage, but only for amorphous fractions higher than 70%. For the untreated pyrochlore sample such a strong signal was not observed in the scattering function. As annealing temperature increases, phase segregation is observed in zircon with a clear nucleation at 850 °C of zirconia grains. The SAXS contribution, however, points towards a lower nucleation temperature, ca. 700 °C. In the pyrochlore structure, at temperatures as low as 300 °C the appearance of a first crystalline phase, Ca2Nb2O7, is observed, with the subsequent crystallization of TiO2 at 800 °C. Observed electron density variations are compared between the two structures and discussed in terms of nanoscale phase segregation phenomena.

p16INK4A, CDC6, and MCM5: predictive biomarkers in cervical preinvasive neoplasia and cervical cancer

AIM

To analyse and compare expression patterns of three potential biomarkers-p16(INK4A), CDC6, and MCM5-and evaluate their use as predictive biomarkers in squamous and glandular cervical preinvasive neoplasia.

METHODS

Immunocytochemical analysis of p16(INK4A), MCM5, and CDC6 expression was performed on 20 normal, 38 cervical intraepithelial neoplasia 1 (CIN1), 33 CIN2, 46 CIN3, 10 squamous cell carcinoma, 19 cervical glandular intraepithelial neoplasia (cGIN), and 10 adenocarcinoma samples. Staining intensity was assessed using a 0-3 scoring system. p16(INK4A), MCM5, and CDC6 expression was also examined in ThinPrep slides exhibiting mild, moderate, and severe dyskaryosis. Human papillomavirus (HPV) was detected using a modified SYBR green assay. Fluorogenic polymerase chain reaction (PCR) and solution phase PCR were used for specific HPV typing.

RESULTS

All three markers showed a linear correlation between expression and grade of dysplasia. p16(INK4A) and MCM5 protein expression was upregulated in all grades of squamous and glandular dysplasia. CDC6 protein was preferentially expressed in high grade lesions and in invasive squamous cell carcinoma.

CONCLUSION

p16(INK4A) expression was closely associated with high risk HPV infection-all grades of squamous and glandular cervical lesions were immunohistochemically positive. MCM5 staining intensity was independent of high risk HPV infection, highlighting its potential as a biomarker in both HPV dependent and independent cervical dysplasia. CDC6 may be a biomarker of high grade and invasive lesions of the cervix, with limited use in low grade dysplasia. p16(INK4A) was the most reliable marker of cervical dysplasia. Combinations of dysplastic biomarkers may be useful in difficult diagnostic cases.

Effects of rate of infusion and probenecid on serum levels, renal excretion, and tolerance of intravenous doses of cefoxitin in humans: comparison with cephalothin

Using a randomized crossover design, 1-g intravenous doses of cephalothin and cefoxitin, a cephalosporinase-resistant cephamycin, were infused into 12 normal adult males over periods of 120, 30, and 3 min, the last with and without prior intravenous infusions of probenecid (1 g). Mean peak serum concentrations of antibiotic activity after cephalothin infusions were 23, 56, 103, and 102 mug/ml, respectively, and after cefoxitin infusions they were 27, 74, 115, and 125 mug/ml, respectively. Probenecid treatment prolonged the terminal serum half-life of cephalothin-like activity from 0.52 to 1.0 h, and of cefoxitin from 0.68 to 1.4 h. In contrast to cephalothin, which was found to be metabolized about 25% to the less active desacetyl form, cefoxitin was metabolized less than 2% to the virtually inactive descarbamyl form, as judged from urinary recoveries. Neither antibiotic displayed detectable organ toxicity. Of 300 recent clinical isolates of gram-negative bacilli other than Pseudomonas spp., 83% were susceptible to cephalothin but 95% were susceptible to cefoxitin. Organisms resistant to cephalothin but susceptible to cefoxitin included strains of Escherichia coli, Proteus vulgaris, Klebsiella spp., Serratia marcescens, Enterobacter spp., and Bacteroides spp.

The ion channel ASIC1 contributes to visceral but not cutaneous mechanoreceptor function

BACKGROUND & AIMS

Visceral mechanoreceptors are critical for perceived sensations and autonomic reflex control of gastrointestinal function. However, the molecular mechanisms underlying visceral mechanosensation remain poorly defined. Degenerin/epithelial Na+ channel (DEG/ENaC) family ion channels are candidate mechanosensory molecules, and we hypothesized that they influence visceral mechanosensation. We examined the influence of the DEG/ENaC channel ASIC1 on gastrointestinal mechanosensory function, on gastric emptying, and on fecal output. We also compared its role in gastrointestinal and somatic sensory function.

METHODS

To assess the role of ASIC1 we studied wild-type and ASIC1-/- mice. Reverse-transcription polymerase chain reaction (RT-PCR) and Western blot analysis determined expression of ASIC1 messenger RNA and protein in vagal and spinal sensory ganglia. Colonic, gastroesophageal, and cutaneous afferent fibers were characterized by functional subtype and their mechanical stimulus-response relationships were determined. Gastric emptying was determined by using a 13CO2 breath test. Behavioral tests assessed somatic mechanical and thermal sensitivity.

RESULTS

ASIC1 was expressed in sensory ganglia and was lost after disruption of the ASIC1 gene. Loss of ASIC1 increased mechanosensitivity in all colonic and gastroesophageal mechanoreceptor subtypes. In addition, ASIC1-/- mice showed almost double the gastric emptying time of wild-type mice. In contrast, loss of ASIC1 did not affect function in any of the 5 types of cutaneous mechanoreceptors, nor did it affect paw withdrawal responses or fecal output.

CONCLUSIONS

ASIC1 influences visceral but not cutaneous mechanoreceptor function, suggesting that different mechanisms underlie mechanosensory function in gut and skin. The role of ASIC1 is highlighted by prolonging gastric emptying of a meal in ASIC1-/- animals.

Effect of haemodilution with diaspirin cross-linked haemoglobin on the oxygen reserve in a rodent model of surgical blood loss

The efficacy of pre-operative haemodilution is limited by the reduction in haemoglobin concentration. Acellular haemoglobin-based oxygen carriers provide an alternative to colloid as a haemodiluent, potentially extending the safe limits of this procedure. The aim of this investigation was to determine whether haemodilution with a cross-linked haemoglobin solution, diaspirin cross-linked haemoglobin solution (DCLHb), would enhance the oxygen reserve compared to pentastarch. Sprague Dawley rats were placed in a metabolic box to directly measure systemic oxygen consumption (VO2). Rats were randomized to be haemodiluted to a cellular haemoglobin of 80 g L(-1) with either DCLHb or pentastarch. Oxygen reserve was assessed during isovolemic haemorrhage by determining the critical oxygen delivery (DO2crit) and haemoglobin concentration at the point of oxygen supply dependency (OSD). Following haemodilution and for the duration of the experiment, cardiac index (CI) was significantly lower and systemic vascular resistance was significantly higher in the DCLHb than the pentastarch group. The DO2crit (3.2 +/- 0.4 mL minAg(-1) and 3.4 +/- 0.5 mL minAg(-1), DCLHb versus pentastarch) and cellular haemoglobin concentration (51 +/- 9 g L(-1) and 48 +/- 9 g L(-1)), at which rats entered OSD were similar in both groups. Total haemoglobin concentration (cellular and plasma DCLHb) and arterial oxygen content were significantly higher in the DCLHb group (total haemoglobin, 66 +/- 8 g L(-1) and arterial content, 9.2 +/- 1.4 mL dL(-1)) compared to the pentastarch group (total haemoglobin, 48 +/- 9 g L(-1) and arterial content, 7.3 +/- 1.4 mL dL(-1)). Oxygen extraction ratios increased from baseline levels to 0.53 +/- 0.07 and 0.56 +/- 0.1, for the DCLHb and pentastarch groups, respectively, and were not significantly different. The increase in arterial oxygen content from DCLHb in plasma was offset by the decrease in CI observed in this group. Plasma DCLHb did not extend the limits of haemodilution beyond the capacity of the cellular haemoglobin concentration.

Potential viral pathogenic mechanism for new variant inflammatory bowel disease

AIMS

A new form of inflammatory bowel disease (ileocolonic lymphonodular hyperplasia) has been described in a cohort of children with developmental disorder. This study investigates the presence of persistent measles virus in the intestinal tissue of these patients (new variant inflammatory bowel disease) and a series of controls by molecular analysis.

METHODS

Formalin fixed, paraffin wax embedded and fresh frozen biopsies from the terminal ileum were examined from affected children and histological normal controls. The measles virus Fusion (F) and Haemagglutinin (H) genes were detected by TaqMan reverse transcription polymerase chain reaction (RT-PCR) and the Nucleocapsid (N) gene by RT in situ PCR. Localisation of the mRNA signal was performed using a specific follicular dendritic cell antibody.

RESULTS

Seventy five of 91 patients with a histologically confirmed diagnosis of ileal lymphonodular hyperplasia and enterocolitis were positive for measles virus in their intestinal tissue compared with five of 70 control patients. Measles virus was identified within the follicular dendritic cells and some lymphocytes in foci of reactive follicular hyperplasia. The copy number of measles virus ranged from one to 300,00 copies/ng total RNA.

CONCLUSIONS

The data confirm an association between the presence of measles virus and gut pathology in children with developmental disorder.

Vagal mechanoreceptors and chemoreceptors in mouse stomach and esophagus

We used a novel in vitro mouse vagus-gastro-esophageal preparation to study the properties of peripheral vagal afferent endings. We found two types of mechanoreceptive fiber, mucosal receptors and tension receptors. These were distinguished by their sensitivity to mucosal stroking with von Frey hairs and circular tension applied via a claw-cantilever system. A comparison was made with gastro-esophageal afferents found in a similar preparation of ferret tissue. Responses of mouse tension receptors to circular tension were significantly greater than ferret tension and tension/mucosal receptors. Similarly the responses of mouse mucosal receptors to mucosal stroking were significantly greater than ferret mucosal and tension/mucosal receptors. Forty-seven percent of mouse mucosal receptors and 50% of tension receptors responded to one or more drugs or chemical stimuli applied to the receptive field. These included alpha,beta-methylene ATP (10(-6) to 10(-3) M), 5-hydroxytryptamine (10(-6) to 10(-3) M), and hydrochloric acid (10(-2) to 10(-1) M). Drug responses were concentration dependent. One hundred percent of mucosal receptors and 61% of tension receptors tested responded to bile (1:8 to 1:1 dilution). A third type of fiber was recruited by bile. These fibers were mechanically insensitive and silent prior to bile exposure. In conclusion, we have shown three types of gastro-esophageal vagal afferent fibers in the mouse: mucosal mechanoreceptors, tension receptors, and specific chemoreceptors activated by bile.

An alternative thermodilution method to measure cardiac output in a rat model of stagnant hypoxia

Rats are often used to study hemodynamics in animal research. We have established an alternative method to measure cardiac output in a conscious rat using a thermodilution technique via a left ventricular injection. The validity of this method was evaluated in conscious rats and compared with the results obtained using the radiolabeled microspheres (reference sample method). Using 20 male Sprague-Dawley rats, a baseline cardiac index was measured by thermodilution to determine the baseline cardiac index and to evaluate between animal variability. The baseline cardiac index was compared to the reference sample method with 6 rats. Following baseline measurements, an intra-atrial balloon was inflated in a stepwise manner to create 2 to 3 different cardiac outputs, and the cardiac index was computed. For each measurement, the cardiac index was first measured by thermodilution and immediately followed by the reference sample method. A total of 21 measurements were obtained, and the results were analyzed by a Bland-Altman plot and the correlation coefficient was calculated. Although the agreement between the two methods was poor, both methods had a good correlation (r2 = 0.59). With the thermodilution technique, we demonstrated a small coefficient of variation in each measurement, with a low intra-animal and inter-animal variability. As there is no gold standard method to measure cardiac output in rats, we believe that left ventricular thermodilution is a reliable method, and overcomes several technical difficulties such as heat loss, one of the significant limitations of the conventional thermodilution method (via right atrial injection). This new thermodilution technique (via the left ventricle) is therefore an attractive alternative method to measure cardiac output in rats.

Diaspirin cross-linked Hb and norepinephrine prevent the sepsis-induced increase in critical O(2) delivery

We hypothesized that support of arterial perfusion pressure with diaspirin cross-linked Hb (DCLHb) would prevent the sepsis-induced attenuation in the systemic O(2) delivery-O(2) uptake relationship. Awake septic rats were treated with a chronic infusion of DCLHb or a reference treatment [norepinephrine (NE)] to increase mean arterial pressure by 10-20% over 18 h. Septic and sham control groups received normal saline. Isovolemic hemodilution to create anemic hypoxia was then performed in a metabolic box during continuous measurement of systemic O(2) uptake. O(2) delivery was calculated from hemodynamic variables, and the critical point of O(2) delivery (DO(2 crit)) was determined using piecewise regression analysis of the O(2) delivery-O(2) uptake relationship. Sepsis increased DO(2 crit) from 4.99 +/- 0.17 to 6.69 +/- 0.42 ml x min(-1) x 100 g(-1) (P < 0.01), while O(2) extraction capacity was decreased (P < 0.05). DCLHb and NE infusion prevented the sepsis-induced increase in DO(2 crit) [4.56 +/- 0.42 ml x min(-1) x 100 g(-1) (P < 0.01) and 5.04 +/- 0.56 ml x min(-1) x 100 g(-1) (P < 0.05), respectively]. This was explained by a 59% increase in O(2) extraction capacity in the DCLHb group compared with septic controls (P < 0.05), whereas NE treatment decreased systemic O(2) uptake in anemic hypoxia (1.51 +/- 0.08 vs. 1.87 +/- 0.1 ml x min(-1) x 100 g(-1) in septic controls, P < 0.05). We conclude that DCLHb ameliorated O(2) extraction capacity in the septic microcirculation, whereas NE decreased the metabolic demands of the tissues.

Suppression of primary tumor growth and the progression to metastasis with p53 adenovirus in human prostate cancer

PURPOSE

Numerous advances have been made in gene therapy approaches for the treatment of solid tumors, including prostate cancer. While treatment of the primary tumor has been well investigated, little information is available regarding gene therapy techniques which might impact on the progression to metastatic disease. We investigate the ability of p53 adenovirus to suppress not only primary tumor growth, but also the progression to metastatic disease. Mutation of the p53 tumor suppressor gene has been associated with the progression of prostate cancer. In this study, we utilized a metastatic model for human prostate cancer to determine if introduction of the wild-type p53 gene using an adenoviral vector (rAd-p53) impacted on primary tumor growth as well as the progression to metastatic disease.

MATERIALS AND METHODS

For our studies, we used the human prostate cancer cell line PC-3, which has a homozygous loss of p53 expression. Expression of exogenous p53 as well as p21 induction at various time points after infection with rAd-p53 was determined in vitro. In vivo studies were performed in nude mice following orthotopic (intraprostatic) injection of PC-3 cells. Primary tumor growth as well as the progression to metastatic disease was assessed following rAd-p53 treatment.

RESULTS

In vitro studies demonstrated high levels of p53 gene expression as well as the induction of p21 gene expression. Infection of PC-3 cells with rAd-p53 resulted in marked growth inhibition, as well as wide-spread fragmentation of nuclei and secretion of nuclear matrix proteins into the culture medium consistent with the process of apoptosis. In vivo studies demonstrated that a single injection of rAd-p53 into an established orthotopic prostate tumor resulted not only in primary tumor growth suppression (treated = 97.5 +/- 25.3 mm.3 versus control = 393.4 +/- 67.2 mm.3; p = 0.0002) but also reduced the frequency of progression to metastatic disease (treated = 8 of 19 versus control = 18 of 19; p = 0.001).

CONCLUSION

These experiments demonstrate that a single injection of rAd-p53 into an established orthotopic prostate tumor results not only in suppression of primary tumor growth, but also in a reduction of the frequency of progression to metastatic disease. These results suggest that a rAd-p53 gene therapy strategy may be useful in the treatment of human prostate cancer.

Increased gut permeability and bacterial translocation in Pseudomonas pneumonia-induced sepsis

OBJECTIVE

Gut injury and barrier dysfunction may contribute to the pathogenesis of sepsis and multiple organ dysfunction syndrome. The objective of this study was to determine whether gut injury could be demonstrated in hyperdynamic, normotensive sepsis induced by Pseudomonas pneumonia.

DESIGN

Randomized animal study.

SETTING

University laboratory.

SUBJECTS

Adult male Sprague-Dawley rats.

INTERVENTIONS

Sepsis was induced by intratracheal instillation of Pseudomonas aeruginosa.

MEASUREMENTS AND MAIN RESULTS

We measured gut mucosal and microvascular injury. In the first experiment, gut mucosal permeability was measured by 51Cr-EDTA uptake in control (n = 6), pneumonia 20-hr (n = 4), and pneumonia 40-hr (n = 4) groups. In the second experiment, microvascular permeability was measured by albumin extravasation, and morphologic abnormalities were scored in control (n = 6), pneumonia 20-hr (n = 9), and pneumonia 40-hr (n = 11) groups. Bacterial translocation to mesenteric lymph nodes was determined in both experiments. Cardiac index increased significantly in the pneumonia compared with control rats (64+/-2.1, 68+/-1.3, vs. 46+/-2 mL/min/100 g, p < .05; all results are listed in the order of pneumonia 20-hr, pneumonia 40-hr, and control groups as mean +/- SEM). Mean blood pressure was normal and was not different between groups (112+/-3, 111+/-2, vs. 118+/-2 mm Hg). 51Cr-EDTA recovery in urine 6 hrs after gavage increased significantly in both pneumonia groups vs. controls (17.5+/-2.2%, 17.9+/-7%, vs. 4+/-0.7%; p < .05). Albumin leak (tissue/plasma ratio) increased significantly in the middle and distal small intestine in the pneumonia 40-hr group vs. controls (0.68+/-0.05, 0.76+/-0.07, vs. 0.45+/-0.04, p < .05 in the middle small gut; 0.75+/-0.09, 0.85+/-0.07, vs. 0.51+/-0.05, p < .05 in the distal small gut). Bacterial translocation to mesenteric lymph nodes increased significantly in pneumonia 40-hr rats vs. controls (positive culture 67% vs. 8%; p < .05).

CONCLUSIONS

This study demonstrates gut mucosal and microvascular injury and gut barrier dysfunction in normotensive sepsis secondary to bacterial pneumonia. The mechanism and significance of the injury need to be determined.

Aqueous and serum interferon gamma, interleukin (IL) 2, IL-4, and IL-10 in patients with uveitis

OBJECTIVE

To determine the cytokine profile in aqueous humor and peripheral blood from patients with uveitis.

METHODS

Cytokines (interferon [IFN]-gamma, interleukin [IL] 2, IL-4, and IL-10) were measured in aqueous humor and peripheral blood samples from 23 patients with uveitis and 16 patients undergoing operation for uncomplicated cataracts (control group) by means of an enzyme-linked immunosorbent assay.

RESULTS

Aqueous and serum samples from patients with uveitis showed higher levels of IFN-gamma and IL-2 than those of controls (P<.001). Similarly, serum IL-10 levels were slightly higher in the uveitis group (P=.002). No differences were found between uveitis and control groups for aqueous and serum IL-4 or aqueous IL-10 levels. In patients with uveitis, IFN-gamma levels were significantly higher in serum than aqueous (P<.001), whereas IL-2 levels were higher in aqueous than in serum (P<.001). Serum IFN-gamma levels correlated with severe visual damage (r=0.44; P=. 03).

CONCLUSIONS

Aqueous and serum levels of IFN-gamma and IL-2 were elevated in patients with uveitis, suggesting a predominantly type 1 response (high IFN-gamma and low IL-4 levels). Elevated serum IFN-gamma level seems to predispose the patient to more serious loss of vision. Arch Ophthalmol. 2000;118:768-772

Levels of soluble ICAM-1 and soluble IL-2R in the serum and aqueous humor of uveitis patients

PURPOSE

To study the ocular and systemic behaviour of the immune activation markers soluble ICAM-1 and soluble IL-2R in patients with active uveitis.

METHODS

We determined the levels of soluble ICAM-1 and soluble IL-2R in the aqueous humor and peripheral blood of 23 patients with active uveitis and 16 age and gender matched controls (who were to undergo cataract extraction) by means of ELISA enzyme immunoanalysis.

RESULTS

Patients with uveitis presented higher levels of soluble ICAM-1 and soluble IL-2R in the aqueous humor and peripheral blood. Comparison of the aqueous humor and peripheral blood revealed higher levels of soluble ICAM-1 in the aqueous humor, while we found no differences for soluble IL-2R. Analysis of the clinical characteristics of the uveitis we studied showed no differences in the levels of these markers in either blood or aqueous humor.

CONCLUSIONS

The finding of elevated levels of soluble IL-2R and soluble ICAM-1 in the aqueous humor and peripheral blood of patients with uveitis suggests the local and systemic participation of these markers in the pathogenesis of uveitis.

Diaspirin cross-linked hemoglobin improves mucosal perfusion in the ileum of septic rats

OBJECTIVE

To determine the effect of a bolus infusion of diaspirin cross-linked hemoglobin (DCLHb or hemoglobin crosfumaril) on the ileal mucosal microcirculation in septic rats.

DESIGN

Prospective, randomized, single-blinded study.

SETTING

University-affiliated animal research laboratory.

SUBJECTS

Twenty-four male Sprague-Dawley rats, weighing 320-380 g.

INTERVENTIONS

Under inhalational anesthesia, arterial and venous catheters were inserted and sepsis was created by cecal ligation and perforation (CLP). Twenty-four hours later, animals were reanesthetized and ventilated. Via midline abdominal incision, the ileum was mobilized and prepared for intravital microscopy. Post-CLP hemodynamic values were obtained, and videomicroscopy was performed on four to ten villi. Animals were then randomized to receive 2 mL of DCLHb solution (100 mg/mL; n = 12) or pentastarch (n = 12) intravenously, and measurements were repeated after 20 mins. Rats treated with DCLHb then received nitroprusside to restore mean arterial pressure to post-CLP levels, and final measurements were obtained 15 mins later.

MEASUREMENTS AND MAIN RESULTS

Cardiac index increased with both treatments (p < .001), whereas systemic vascular resistance index and mean arterial blood pressure were augmented only with DCLHb (p < .0001 compared with pentastarch). Intercapillary areas (ICA; inversely related to capillary density) were determined using computerized image analysis. ICA size decreased after treatment, from 974 +/- 79 to 791 +/- 106 microm2 with DCLHb and from 1044 +/- 90 to 840 +/- 82 microm2 with pentastarch (both p < .05). Red blood cell velocity in terminal arterioles, as assessed by velocimetry from the recorded images, increased by 15% with both treatments (p < .05). Restoration of mean arterial pressure to post-CLP levels in DCLHb animals by nitroprusside infusion abolished the effects of the hemoglobin solution on ICA size and red blood cell velocity.

CONCLUSION

Both DCLHb and pentastarch infusion improved microcirculatory perfusion in the ileum of septic rats. In addition, DCLHb also exhibited vasopressor properties, which in combination with improved perfusion may be particularly useful in the treatment of sepsis.

The Critical Care Research Network: a partnership in community-based research and research transfer

The objectives of this study were to present a short history of the Critical Care Research Network (CCR-Net), describe its approach to health services research and to summarize completed and current research projects. In doing this, we explored the question is this research network accomplishing its goals? We reviewed the medical literature to identify studies on similar types of Networks and also the evidence supporting the methodology used by CCR-Net to conduct research using MEDLINE, HEALTHSTAR, CINAHL and the keywords network and health care or healthcare, benchmarking and health care or healthcare, and research transfer or research utilization. We also reviewed the bibliographies of retrieved articles and our personal files. In addition, we summarized the results of studies conducted by CCR-Net and outlined those currently in progress. A review of the literature identified studies on two similar networks that appeared to be succeeding. In addition, the literature was also supportive of the general process used by CCR-Net, although the level of evidence varied. Finally, the studies conducted to date within CCR-Net follow the suggested methodology. At the time of this preliminary communication CCR-Net appears to have adopted a valid approach to health services research within the area of Critical Care Medicine. Further direct evidence is required and appropriate studies are planned.

Effects of modest anemia on systemic and coronary circulation of septic sheep

Although a lower transfusion trigger is generally recommended, little evidence is available about the physiological mechanisms of mild anemia in diseases with an imbalance between O2 supply and O2 demand such as sepsis. This study was undertaken to describe the systemic and coronary metabolic O2 reserve in an awake sheep model of hyperdynamic sepsis comparing two different hemoglobin levels. Twenty-four hours after sheep were rendered septic by cecal ligation and perforation (CLP), blood transfusion (n = 7, hemoglobin = 120 g/l) and isovolemic hemodilution (n = 8, hemoglobin = 70 g/l), respectively, were performed. Another 24 h later, we measured hemodynamics, organ blood flows, and systemic and myocardial O2 metabolism variables at baseline and through four stages of progressive hypoxia. Maximum coronary blood flow was 766.3 +/- 87.4 ml. min(-1). 100 g(-1) in hemodiluted sheep group versus 422.7 +/- 53.7 ml. min(-1). 100 g(-1) in the transfused sheep (P < 0.01). Myocardial O2 extraction was higher in the transfusion group (P = 0.03) throughout the whole hypoxia trial. In the hemodilution group, coronary blood flow increased more per increase in myocardial O(2) uptake than in transfused sheep (P < 0.01). This was accompanied by a lower left ventricular epicardial-to-endocardial flow ratio in hemodiluted sheep (1.13 +/- 0.07) than in transfused sheep (1.34 +/- 0.02, P < 0.05). We conclude that the lower coronary blood flow and greater myocardial O2 extraction in transfused septic sheep preserves transmyocardial O2 metabolism better in comparison to hemodiluted sheep.