Major histocompatibility complex and kin discrimination in Atlantic salmon and brook trout

Many species of salmonids can discriminate kin from unrelated conspecifics using olfactory cues. In this study, we determined the role of the major histocompatibility complex (MHC) in kin discrimination by juvenile Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis). Genetic variation at the highly polymorphic exon coding for peptide-binding region of an MHC class II gene was studied using polymerase chain reaction and denaturing gradient gel electrophoresis. Experiments compared discrimination ability based on MHC haplotypes both within and among kin and non-kin groups. Juveniles chose kin sharing both alleles over kin sharing no alleles. Juveniles also preferred non-kin sharing both alleles to non-kin sharing no alleles. These data suggest that the MHC class II gene influence kin discrimination in juvenile Atlantic salmon and brook trout. The influence of additional genes was also apparent in trials where juveniles were able to recognize kin sharing no alleles over non-kin sharing no alleles. However, the inability of juveniles to discriminate between kin sharing no alleles and non-kin sharing either one or both alleles indicates that MHC is as potent as the rest of the genome in producing distinguishable odours.

Resting and Postexercise Cardiac Autonomic Control in Trained Masters Athletes

This study used measures of heart rate variability during recovery from high-intensity exercise in trained Master athletes to examine postexercise cardiac autonomic regulation. Seven males (mean age 52.1 +/- 3.3 yr; mass 85.1 +/- 18.0 kg) and 6 females (mean age 50.5 +/- 2.9 yr; mass 63.1 +/- 6.0 kg) performed incremental exercise to an intensity that induced a >4.5 mmol capillary blood lactate concentration, followed by incremental exercise to volitional exhaustion (VO2(max)). A 6 min ECG recording before (Pre) and after (Post) exercise was analyzed in the time (mean rr interval, sd rr) and frequency domains (total power, very low frequency [VLF: 0-0.04 Hz], low frequency [LF: 0.04-0.15 Hz], high frequency [HF: 0.15-0.4 Hz]). VO2(max) for males and females was 49.4 +/- 7.1 ml kg(-1) min(-1) and 45.1 +/- 10.1 ml kg(-1) min(-1), respectively. Lower mean rr interval (Pre: 1,048 +/- 128 ms; Post: 730 +/- 78 ms; P < 0.001) and lower sd rr (Pre: 77 +/- 30 ms; Post: 43 +/- 17 ms; P < 0.001) were recorded following exercise, with no differences based on gender. Total power decreased following exercise (Pre: 6,331 +/- 6,119 ms; Post: 1,921 +/- 1,552 ms). When normalized for changes in total power, a decreased HF component (Pre: 34.52 +/- 14.79 n.u.; Post: 18.49 +/- 13.64 n.u.; P < 0.05) with no change in LF component (Pre: 61.00 +/- 18.66 n.u.; Post: 69.63 +/- 23.97 n.u.; P = 0.34) was recorded. No gender differences in HRV in the frequency domain were recorded. Decreased heart rate variability in both time and frequency domains suggested an increased parasympathetic withdrawal during the autonomic control of postexercise tachycardia in trained Master athletes.

PD-1 expression on HIV-specific T cells is associated with T-cell exhaustion and disease progression

Functional impairment of T cells is characteristic of many chronic mouse and human viral infections. The inhibitory receptor programmed death 1 (PD-1; also known as PDCD1), a negative regulator of activated T cells, is markedly upregulated on the surface of exhausted virus-specific CD8 T cells in mice. Blockade of this pathway using antibodies against the PD ligand 1 (PD-L1, also known as CD274) restores CD8 T-cell function and reduces viral load. To investigate the role of PD-1 in a chronic human viral infection, we examined PD-1 expression on human immunodeficiency virus (HIV)-specific CD8 T cells in 71 clade-C-infected people who were naive to anti-HIV treatments, using ten major histocompatibility complex (MHC) class I tetramers specific for frequently targeted epitopes. Here we report that PD-1 is significantly upregulated on these cells, and expression correlates with impaired HIV-specific CD8 T-cell function as well as predictors of disease progression: positively with plasma viral load and inversely with CD4 T-cell count. PD-1 expression on CD4 T cells likewise showed a positive correlation with viral load and an inverse correlation with CD4 T-cell count, and blockade of the pathway augmented HIV-specific CD4 and CD8 T-cell function. These data indicate that the immunoregulatory PD-1/PD-L1 pathway is operative during a persistent viral infection in humans, and define a reversible defect in HIV-specific T-cell function. Moreover, this pathway of reversible T-cell impairment provides a potential target for enhancing the function of exhausted T cells in chronic HIV infection.

Programmed death-1 (PD-1) is a marker of germinal center-associated T cells and angioimmunoblastic T-cell lymphoma

Programmed death-1 (PD-1), a member of the CD28 costimulatory receptor family, is expressed by germinal center-associated T cells in reactive lymphoid tissue. In a study of a wide range of lymphoproliferative disorders, neoplastic T cells in 23 cases of angioimmunoblastic lymphoma were immunoreactive for PD-1, but other subtypes of T cell and B cell non-Hodgkin lymphoma, as well as classic Hodgkin lymphoma, did not express PD-1. The pattern of PD-1 immunostaining of neoplastic cells in angioimmunoblastic lymphoma was similar to that reported for CD10, a recently described marker of neoplastic T cells in angioimmunoblastic lymphoma. Tumor-associated follicular dendritic cells in cases of angioimmunoblastic lymphoma were found to express PD-L1, the PD-1 ligand. In addition, PD-1-positive reactive T cells formed rosettes around neoplastic L&H cells in 14 cases of nodular lymphocyte predominant Hodgkin lymphoma studied. These findings, along with data from previous studies, suggest that angioimmunoblastic lymphoma is a neoplasm of germinal center-associated T cells and that there is an association of germinal center-associated T cells and neoplastic cells in nodular lymphocyte predominant Hodgkin lymphoma. PD-1 is a useful new marker for angioimmunoblastic lymphoma and lends further support to a model of T-cell lymphomagenesis in which specific subtypes of T cells may undergo neoplastic transformation and result in specific, distinct histologic, immunophenotypic, and clinical subtypes of T-cell neoplasia.

Healthcare use before and after a workplace injury in British Columbia, Canada

OBJECTIVES

There is growing evidence that occupational injuries influence workers' emotional and physical wellbeing, extending healthcare use beyond what is covered by the Workers' Compensation Board (WCB).

METHODS

The authors used an administrative database that links individual publicly funded healthcare and WCB data for the population of British Columbia (BC), Canada. They examined change in service use, relative to one year before the injury, for workers who required time off for their injuries (lost time = LT) and compared them to other injured workers (no lost time = NLT) and individuals in the population who were not injured (non-injured = NI).

RESULTS

LT workers increased physician visits (22%), hospital days (50%), and mental healthcare use (43% physician visits; and 70% hospital days) five years after the injury, relative to the year before the injury, at a higher rate than the NI group. For the NLT workers, the level of increased use following the injury was between that of these two groups. These patterns persisted when adjusting for registration in the BC Medical Service Plan (MSP) and several workplace characteristics.

CONCLUSIONS

Although the WCB system is the primary mechanism for processing claims and providing information about workplace injury, it is clear that the consequences of workplace injury extend beyond what is covered by the WCB into the publicly funded healthcare system.

European eels, Anguilla anguilla (L.), infected with Anguillicola crassus exhibit a more pronounced stress response to severe hypoxia than uninfected eels

The parasite, Anguillicola crassus is a non-native species that infects naive European eels, Anguilla anguilla, and causes pathological damage to the swimbladder, potentially compromising their ability to cope with hypoxic conditions. This study aimed to elucidate whether anguillicolosis exacerbates the stress responses to exposure to hypoxic water, conditions that have been implicated in mass mortalities of wild infected European eels. Blood parameters in infected and uninfected eels were measured during exposure to severe hypoxia over an 8-h period. Infected fish showed significantly higher levels of plasma cortisol compared with uninfected eels after 4 h of hypoxia. Uninfected fish showed an almost twofold increase in plasma glucose after 8-h exposure to hypoxia but infected fish showed no significant change, so that the plasma glucose concentration was significantly higher in uninfected eels than in infected eels. Both groups showed similar elevations in blood haematocrit, suggesting a similar catecholamine response in infected and uninfected eels. The lack of a hyperglycaemic response in infected eels, despite indirect evidence of a catecholamine response to hypoxia, may reflect an increase in glucose turnover. The data suggest that anguillicolosis results in a significantly greater corticosteroid stress response to hypoxia accompanied by a higher metabolic cost.

Detection of influenza A in clinical specimens and cell culture fluid by a commercial EIA

A MoAb-based capture EIA for the direct detection of influenza A from clinical samples was compared with cell culture isolation. A total of 330 respiratory specimens were submitted for detection of influenza A and/or other respiratory viruses. Influenza A was detected in 39 of 330 (12%) respiratory samples by culture or EIA. There were 33 concordant (EIA+/Culture-) samples (82%), and 6 discordant samples (3 EIA +/Culture-; 3 EIA-/Culture+). Compared to viral isolation, the EIA had a sensitivity of 92%, a specificity of 98%, with positive and negative predictive values of 92% and 99%, respectively.

The role of hyaluronic acid in wound healing’s proliferative phase

This review discusses the multifaceted role of hyaluronic acid, focusing on the proliferative phase of wound healing. It considers the importance of achieving the right levels of this molecule, and the potential for future therapies.

Relationships Among Rheological and Sensorial Properties of Young Cheeses

This study investigated the sensory and rheological properties of young cheeses in order to better understand perceived cheese texture. Mozzarella and Monterey Jacks were tested at 4, 10, 17, and 38 d of age; process cheese was tested at 4 d. Rheological methods were used to determine the linear and nonlinear viscoelastic and fracture properties. A trained sensory panel developed a descriptive language and reference scales to evaluate cheese texture. All methods differentiated the cheeses by variety. Principal component analysis of sensory texture revealed that three principal components explained 96.1% of the total variation in the cheeses. The perception of firmness decreased as the cheeses aged, whereas the perception of springiness increased. Principal component analysis of the rheological parameters (three principal components: 87.9% of the variance) showed that the cheeses' solid-like response (storage modulus and fracture modulus) decreased during aging, while phase angle, maximum compliance, and retardation time increased. Analysis of the instrumental and sensory parameters (three principal components: 82.1% of the variance) revealed groupings of parameters according to cheese rigidity, resiliency, and chewdown texture. Rheological properties were highly associated with rigidity and resiliency, but less so with chewdown texture.

Esophageal foreign body causing direct aortic injury

Foreign bodies in the esophagus are uncommon causes of esophageal perforation. Many nonperforating cases are successfully managed by flexible gastroscopy. However, complicated foreign bodies such as those that result in esophageal perforation and vascular injury are best managed surgically. Gastroscopy remains the primary method of diagnosis. A case of a 59-year-old woman who developed retrosternal and intrascapular pain, odynophagia and hematemesis after eating fish is reported. Flexible gastroscopy showed arterial bleeding from the midthoracic esophagus. Computed tomography scan localized a 3 cm fish bone perforating the esophagus with surrounding hematoma. An aortogram did not reveal an actively bleeding aortoesophageal fistula. The fish bone was surgically removed and the patient recovered with no postoperative complications. This case illustrates the importance of early consideration for surgical intervention when confronted with a brisk arterial bleed from the esophagus with suggestive history of foreign body ingestion.

Blockade of programmed death-1 ligands on dendritic cells enhances T cell activation and cytokine production

Programmed death-1 ligand (PD-L)1 and PD-L2 are ligands for programmed death-1 (PD-1), a member of the CD28/CTLA4 family expressed on activated lymphoid cells. PD-1 contains an immunoreceptor tyrosine-based inhibitory motif and mice deficient in PD-1 develop autoimmune disorders suggesting a defect in peripheral tolerance. Human PD-L1 and PD-L2 are expressed on immature dendritic cells (iDC) and mature dendritic cells (mDC), IFN-gamma-treated monocytes, and follicular dendritic cells. Using mAbs, we show that blockade of PD-L2 on dendritic cells results in enhanced T cell proliferation and cytokine production, including that of IFN-gamma and IL-10, while blockade of PD-L1 results in similar, more modest, effects. Blockade of both PD-L1 and PD-L2 showed an additive effect. Both whole mAb and Fab enhanced T cell activation, showing that PD-L1 and PD-L2 function to inhibit T cell activation. Enhancement of T cell activation was most pronounced with weak APC, such as iDCs and IL-10-pretreated mDCs, and less pronounced with strong APC such as mDCs. These data are consistent with the hypothesis that iDC have a balance of stimulatory vs inhibitory molecules that favors inhibition, and indicate that PD-L1 and PD-L2 contribute to the poor stimulatory capacity of iDC. PD-L1 expression differs from PD-L2 in that PD-L1 is expressed on activated T cells, placental trophoblasts, myocardial endothelium, and cortical thymic epithelial cells. In contrast, PD-L2 is expressed on placental endothelium and medullary thymic epithelial cells. PD-L1 is also highly expressed on most carcinomas but minimally expressed on adjacent normal tissue suggesting a role in attenuating antitumor immune responses.

Nonsteroidal anti-inflammatory drug-induced colonic stricture: case report

Nonsteroidal anti-inflammatory drug-induced colonic strictures are uncommon and usually occur in the proximal ascending colon. We describe the progressive findings of nonsteroidal anti-inflammatory drug-induced strictures in the ascending colon and at the ileocecal valve with subsequent bowel obstruction secondary to intussusception.

CDP840. A prototype of a novel class of orally active anti-inflammatory phosphodiesterase 4 inhibitors

The discovery, synthesis and biological activity of a series of triarylethane phosphodiesterase 4 inhibitors is described. Structure-activity relationship studies are presented for CDP840 (29), a potent, chiral, selective inhibitor of PDE 4 (IC(50) 4nM). CDP840 is non-emetic in the ferret at 30mgkg(-1) (po), active in models of inflammation and reverses ozone-induced bronchial hyperreactivity in the guinea pig.

T helper differentiation in resistant and susceptible B7-deficient mice infected with Leishmania major

The contribution of the costimulatory molecules B7-1 and B7-2 to the in vivo differentiation of Th cells remains controversial. The infection of resistant and susceptible strains of mice with the parasite Leishmania major provides a well-established model for studying in vivo differentiation of CD4+ T cells. We have infected B7-1/B7-2-deficient mice on the BALB/c and 129 background with L. major and subsequently examined different parameters of infection and cytokine responses upon restimulation of lymph node cells in vitro. BALB/c B7-2-deficient and B7-1/B7-2-double deficient mice are resistant to L. major, whereas BALB/c B7-1-deficient mice remain as susceptible as wild-type BALB/c mice. Differential expression of B7-1 and B7-2 can explain the distinct roles observed for these B7 costimulators in L. major infection.

Foraging behaviour of Atlantic cod (Gadus morhua) larvae in relation to prey concentration

In spite of a tremendous amount of research on Atlantic cod (Gadus morhua) larvae, no information is available on the development of foraging behaviour over an extended period. We investigated the ontogeny of foraging behaviour of Atlantic cod larvae exposed to different prey concentrations from hatching to metamorphosis. The objective of this work was to determine if their foraging behaviour is influenced by prey concentration. Rotifers and (or) Artemia sp. were used as prey at concentrations of 0, 500, 1000, 2000, and 4000/L. During behavioural observations, which were carried out twice a week, foraging behaviour and activity of cod larvae were quantified. Larvae were sampled once a week and standard length and gut fullness were recorded. Larvae reared at concentrations of 1000 and 2000 prey/L swam significantly more but foraged (quantified by capture success) significantly less than the larvae reared at 4000 prey/L. Larvae reared at 4000 prey/L performed more orientations towards prey than larvae reared at all lower prey concentrations and the time spent per orientation increased from day 2 at all prey concentrations but declined as the larvae grew. However, this decline occurred earlier in larvae reared at 4000 prey/L than in larvae reared at other prey concentrations, and larvae reared at 4000 prey/L spent the shortest time per orientation at day 27 compared with day 34. Larvae reared at 4000 prey/L showed significantly higher success in capturing prey than larvae reared at all lower prey concentrations. After day 13 post hatch, larvae reared at 4000 prey/L were significantly greater in length than larvae reared at all other prey concentrations. Larvae reared at 0, 500, and 1000 prey/L did not survive beyond 11, 15, and 32 days, respectively, indicating that fewer than 2000 prey/L may not be adequate to keep cod larvae alive during intensive rearing. Our results suggest that the foraging behaviour of Atlantic cod larvae is influenced by prey concentration.

Endoscopic diagnosis of a right hepatic artery pseudoaneurysm

Hepatic artery aneurysms are rare occurrences with diverse etiologies. We present a case of a right hepatic artery aneurysm, which was diagnosed at endoscopic retrograde cholangiography (ERC) and treated angiographically. This is the first report where ERC has been critical in delineating the aneurysmal cavity, suggesting the diagnosis and prompting emergency intervention.

Motor cortex stimulation

In 1991 Tsubokawa and colleagues first published their landmark results from a series in which epidural motor cortex stimulation (MCS) was used in the treatment of eight patients with central and neuropathic pain. In ensuing studies authors have elaborated on the indications, technique, hypotheical mechanisms, and beneficial results of this treatment. Epidural MCS is effective for trigeminal neuropathy, lateral medullary and thalamic infarction, anesthesia dolorosa, postherpetic neuralgia, spinal cord injury, and limb stump pain. Postoperative outcomes are better when patients present with only mild or absent motor weakness in the region of pain and when there is pain in the trigeminal region. It is hypothesized that MCS is effective because it increases regional cerebral blood flow in the ipsilateral ventrolateral thalamus in which corticothalamic connections from the motor and premotor areas predominate. The extent of pain alleviation also correlates with the increase of blood flow in the cingulate gyrus. This suggests that stimulation reduces the suffering experienced by a patient with chronic pain. Procedure-related morbidity has included epidural hematoma, subdural effusion, gradual diminution of benefit, and painful stimulation. Although of concern, treatment-induced chronic seizure disorders have not occurred as a complication or in animal models of chronic cortical stimulation. Stimulation-induced pain relief occurs within minutes. There are no associated paresthesias or muscle contractions that confirm function. Pain relief may last for hours after electrical stimulation is discontinued. Motor cortex stimulation is an established therapy for the treatment of complex central and neuropathic pain syndromes that have proved refractory to medical treatment.

CD4+CD25high regulatory cells in human peripheral blood

Thymectomy in mice on neonatal day 3 leads to the development of multiorgan autoimmune disease due to loss of a CD(+)CD25(+) T cell regulatory population in their peripheral lymphoid tissues. Here, we report the identification of a CD4(+) population of regulatory T cells in the circulation of humans expressing high levels of CD25 that exhibit in vitro characteristics identical with those of the CD4(+)CD25(+) regulatory cells isolated in mice. With TCR cross-linking, CD4(+)CD25(high) cells did not proliferate but instead totally inhibited proliferation and cytokine secretion by activated CD4(+)CD25(-) responder T cells in a contact-dependent manner. The CD4(+)CD25(high) regulatory T cells expressed high levels of CD45RO but not CD45RA, akin to the expression of CD45RB(low) on murine CD4(+)CD25(+) regulatory cells. Increasing the strength of signal by providing either costimulation with CD28 cross-linking or the addition of IL-2 to a maximal anti-CD3 stimulus resulted in a modest induction of proliferation and the loss of observable suppression in cocultures of CD4(+)CD25(high) regulatory cells and CD4(+)CD25(-) responder cells. Whereas higher ratios of CD4(+)CD25(high) T cells are required to suppress proliferation if the PD-L1 receptor is blocked, regulatory cell function is shown to persist in the absence of the PD-1/PD-L1 or CTLA-4/B7 pathway. Thus, regulatory CD4 T cells expressing high levels of the IL-2 receptor are present in humans, providing the opportunity to determine whether alterations of these populations of T cells are involved in the induction of human autoimmune disorders.

Circulating angiotensins in the river lamprey, Lampetra fluviatilis, acclimated to freshwater and seawater: possible involvement in the regulation of drinking

Plasma angiotensin levels were measured for the first time in a cyclostome, the river lamprey. With the demonstration that angiotensins are present in the circulation, the possibility of a physiological role in the regulation of drinking was re-examined. Angiotensin II and III concentrations and plasma osmolalities were significantly higher in lampreys acclimated to 28 ppt seawater than in those acclimated to freshwater. No changes were found in angiotensin II and III levels 4 h after transfer from freshwater to 50% seawater, although plasma osmolality had started to rise by this time. There was a suggestion that plasma angiotensin II levels might be related to osmolality in the transfer experiment. Injection of Asp(1)Val(5)- or Asn(1)Val(5)-angiotensin II (40-169 microg/kg body wt.) did not stimulate drinking in freshwater-acclimated lampreys, even when they were still capable of drinking. The angiotensin-converting enzyme inhibitor captopril and the smooth muscle relaxant papaverine both reduced drinking rate in 50% seawater-acclimated lampreys. The data do not provide direct evidence for the involvement of the renin-angiotensin system in the control of drinking behaviour in the lamprey. Indirect evidence from the captopril effect is suggestive, but could have other explanations.

Production of antifreeze glycoproteins in cultured and wild juvenile Atlantic cod (Gadus morhua L.) in a common laboratory environment

Many fishes accumulate antifreeze proteins or antifreeze glycoproteins (AFGPs) in the blood to increase their chances of survival in cold seawater. Cod (Gadus morhua L.) from colder environments have been found to produce more AFGPs than those from warmer areas, but the genetic and environmental contributions to this variation have not been determined. Populations of cultured (from the Grand Banks; Gulf of Maine) and wild (from Fortune Bay; Bonavista Bay) juvenile cod were kept in a common laboratory environment to investigate differences in AFGP production. All the populations were capable of producing AFGPs, and the AFGP levels were similar in cultured and wild cod. The results indicate that high temperatures associated with the production of cultured cod do not negatively affect the ability to produce AFGPs. In addition, young cod from as far south as the Gulf of Maine are capable of producing AFGPs at levels similar to those from the northeast coast of Newfoundland.

Discovery of zoniporide: a potent and selective sodium-hydrogen exchanger type 1 (NHE-1) inhibitor with high aqueous solubility

Zoniporide (CP-597,396) is a potent and selective inhibitor of NHE-1, which exhibits high aqueous solubility and acceptable pharmacokinetics for intravenous administration. The discovery, synthesis, activities, and rat and dog pharmacokinetics of this compound are presented. The potency and selectivity of zoniporide may be due to the conformation that the molecule adopts due to the presence of a cyclopropyl and a 5-quinolinyl substituent on the central pyrazole ring of the molecule.