Comparison of 10 × 1-minute high-intensity interval training (HIIT) versus 4 × 4-minute HIIT on glucose control and variability in females with type 2 diabetes

Two high-intensity interval training (HIIT) regimens are often used in research and clinical settings. Yet, there has been no direct comparison to determine if one can improve glucose control and variability to a greater extent in individuals living with type 2 diabetes (T2D). Fourteen older females with T2D participated in a semi-randomized control trial where HIIT10 (10 × 1-min intervals at 90% heart rate max; HRmax) and HIIT4 (4 × 4-min intervals at 90% of HRmax) were compared to a control condition (CON; no exercise). Continuous glucose monitoring was used to assess glucose control and variability over 24 h after each condition. Both HIIT10 (-2.1 ± 1.1 mmol/L) and HIIT4 (-2.1 ± 1.3 mmol/L) acutely lowered glucose compared to CON (-0.7 ± 0.8 mmol/L; p = 0.001), with no difference between exercise conditions. This glucose-lowering effect did not persist over the 24-h post-exercise period, as both mean glucose (p = 0.751) and glucose variability (p = 0.168) were not significantly different among conditions. However, exploratory analyses focusing on individuals with less optimal glucose control (above median 24-h mean glucose in the CON condition; n = 7) revealed that 24-h mean glucose (7.4 [7.14-8.92] vs. 8.4 [7.5-9.9] mmol/L; p = 0.048), glucose variability (p = 0.010), and peak glucose (p = 0.048) were lower following HIIT10 compared to CON, while HIIT4 reduced time spent in moderate hyperglycemia compared to CON (p = 0.023). Both HIIT10 and HIIT4 acutely lower glycemia, but the effect does not persist over 24 h. However, in individuals with worse glucose control, HIIT10 may improve mean 24-h glucose and glycemic variability, while HIIT4 may reduce time spent in moderate hyperglycemia.

Food Animal Matters

This column is a communications tool for food animal production and related issues. It is expected to fill an important gap, as much of the narrative regarding food animal agriculture and food animal veterinary practice is not written by food animal veterinarians. This column will be a regular feature of The CVJ, coordinated by Dr. Robert Tremblay and intended to inform food animal veterinarians and others who want to understand more about the day-to-day professional activities of food animal veterinarians. Recently retired, Dr. Tremblay spent 40 y in professional life working in large animal veterinary medicine. For most of that time, his primary interest was food animal medicine. Dr. Tremblay takes great satisfaction in having been involved in food animal veterinary medicine. He is grateful to have worked with dedicated food animal veterinarians, farmers, and ranchers in Canada and beyond. Tim Ogilvie John Kastelic.

Association of childhood externalizing, internalizing and comorbid symptoms with long-term economic outcomes

Introduction

Externalising and internalising problems are common in school-aged children. Few studies have examined the association between comorbid externalising and internalising symptoms and adult-life economic participation.

Objectives

To investigate associations of childhood externalising, internalising, and comorbid internalising-externalising symptoms with earnings and welfare receipt in adulthood.

Methods

We used group-based trajectory modeling to identify profiles of children with externalising, internalising, and comorbid symptoms from age 6-12 years. We estimated associations of the identified profiles with participants’ employment earnings at age 33-37 years and welfare receipt from age 18-35 years obtained from tax return records. The child’s IQ and family socioeconomic background were adjusted for.

Results

Four profiles were identified: no symptoms (45%), externalizing (29%), internalizing (11%) and comorbid symptoms (13%). Relative to the no-symptom profile, participants in the comorbid profile earned US$-18,323 less annually (95%CI=-20,925 to -15700) at age 33-37 years and were significantly more likely to receive welfare across follow-up (RR=6.30, 95%CI=5.4 to 7.2). Similarly, compared to the no-symptom profile, participants in the externalising profile earned US$-7,256 less per year (95%CI=-9,205 to -5,307), while participants in the internalising profile earned US$-9,716 less (95%CI=-12,358 to -7,074). Significant interactions by sex were observed. For participants in the comorbid profile, males were more likely to have lower earnings while females were more likely to receive welfare, relative to the no-symptom profile.

Conclusions

Children exhibiting comorbid externalising and internalising symptoms are at high risk of poor economic outcomes in adulthood. Early detection, prevention and management is crucial to improve the life chances of this vulnerable population.

Disclosure

No significant relationships.

Childhood behaviours and adverse economic and social outcomes – can we improve detection and prevention?

Introduction

Disruptive behaviours underpin the most prevalent and costly psychiatric disorders in youth including ADHD and conduct disorder. Yet the association between childhood behavioural problems and economic and social outcomes in adulthood are rarely examined in a population-based samples where early detection and prevention may be possible.

Objectives

To examine the association childhood behavioural problems and economic and social outcomes from age 18-35 years across three studies.

Methods

This study daws on 30-year Canadian birth cohort (n=3017) linked to government tax return records. Behavioural assessments – for inattention, hyperactivity, opposition, aggression, anxiety and prosociality – were prospectively obtained from teachers when children were aged 6-12 years. Regression models were used to link behavioural assessments in kindergarten (age 5/6 years) to earnings at age 33-35 years (Study 1) and to trajectories of welfare receipt (Study 2), while behaviour at age 10-12 years was linked to trajectories of partnering. Children’s IQ and family background were adjusted for.

Results

Inattention, aggression-opposition (males only) and low low-prosociality in kindergarten were associated with lower earnings at age 33-35 years (Study 1), inattention, aggression-opposition and low prosociality in kindergarten predicted following a chronic welfare receipt trajectory from age 18-35 (Study 2), and inattention, aggression-opposition, anxiety and low-prosociality at age 10-12 years were associated with increased likelihood of being unpartnered and with partnership dissolution from age 18-35 years (Study3).

Conclusions

Behavioural assessments made by schoolteachers can identify children at risk of adverse economic and social outcomes in adulthood. The implications of for early screening and prevention will be discussed.

Disclosure

No significant relationships.

Behaviour in childhood is associated with distinct patterns of partnering in adulthood

Introduction

Childhood behavioral problems are highly prevalent in school-aged children and are associated with poor long-term outcomes. Yet little is known about their association with patterns of partnering in adulthood.

Objectives

To (1) describe patterns of partnering from age 18-35 years in a large population-based sample, and (2) examine the association between childhood behavioural problems and adult partnering patterns.

Methods

Behavioural ratings were prospectively obtained from teachers when children (n=2960) were aged 10-12 years – for inattention, hyperactivity, aggression-opposition, anxiety and prosociality – and linked to their tax return records from age 18-35 years. We used group-based trajectory modelling to identify distinct trajectories of partnering (married or cohabitating) and multinomial regression models to examine the association between childhood behaviour and trajectory group membership.

Results

Five distinct trajectories of partnering were identified: early-partnered (n=420, 14.4%), mid-partnered (n=620, 21.3%), late-partnered (n=570, 19.2%), early-separated (n=460, 15.5%), and delayed-or-unpartnered (n=890, 30.0%). After adjustment for sex and family background, children rated as being anxious or inattentive were more likely to remain unpartnered from age 18 to 35 years, while those rated as aggressive-oppositional or inattentive were more likely to separate and return to unpartnered status. Prosocial behaviours were consistently associated with earlier and more sustained partnership. Participants in the early-separated and delayed-or-unpartnered trajectories were also more likely to have left high school without a diploma and to have lower earnings.

Conclusions

Childhood behavioural problems were associated with increased likelihood of being unpartnered and of partnership dissolution, which has implications for the psychological health and wellbeing of individuals and their families.

Local cold adaption increases the thermal window of temperate mussels in the Arctic

Species expand towards higher latitudes in response to climate warming, but the pace of this expansion is related to the physiological capacity to resist cold stress. However, few studies exist that have quantified the level of inter-population local adaptation in marine species freeze tolerance, especially in the Arctic. We investigated the importance of cold adaptation and thermal window width towards high latitudes from the temperate to the Arctic region. We measured upper and lower lethal air temperatures (i.e. LT and LT50) in temperate and Arctic populations of blue mussels (Mytilus edulis), and analysed weather data and membrane fatty acid compositions, following emersion simulations. Both populations had similar upper LT (~38 °C), but Arctic mussels survived 4°C colder air temperatures than temperate mussels (-13 vs. -9°C, respectively), corresponding to an 8% increase in their thermal window. There were strong latitudinal relationships between thermal window width and local air temperatures, indicating Arctic mussels are highly adapted to the Arctic environment where the seasonal temperature span exceeds 60°C. Local adaptation and local habitat heterogeneity thus allow leading-edge M. edulis to inhabit high Arctic intertidal zones. This intraspecific pattern provides insight into the importance of accounting for cold adaptation in climate change, conservation and biogeographic studies.

Influence of the timing of weaning on growth and survival of juvenile winter flounder (Pseudopleuronectes americanus)

Metamorphosis is a critical developmental stage that presents particular challenges in fish aquaculture. The sharp increase in mortality that accompanies this transformation has often been attributed to nutritional deficiencies. Providing live feed (the rotifer Brachionus plicatilis Müller, 1786 and the brine shrimp Artemia salina (Linnaeus, 1758)) during the larval stages is costly and labour intensive, which explains why much effort has been put on early weaning. However, previous observations in winter flounder (Pseudopleuronectes americanus (Walbaum, 1792)) indicate that juveniles weaned after settlement had better survival than those weaned at the larval stage. In this study, we tested whether late weaning (at settlement (W0) and groups maintained on co-feeding for 1 month (W1), two months (W2), or 3 months (W3) after settlement) could improve juvenile survival and lipid composition. Our results demonstrated that maintaining co-feeding beyond the larval stage was essential for after-settlement survival. Juveniles co-fed until 90 days after settlement were 32.5% heavier. Analyses of fatty acid trophic markers suggested that juveniles preferentially fed on enriched rotifers rather than inert food. No pigmentation or fin erosion problems were observed in any of the weaning treatments, which indicates good rearing conditions.

Divergence in physiological factors affecting swimming performance between anadromous and resident populations of brook charr Salvelinus fontinalis

In this study, an anadromous strain (L) and a freshwater-resident (R) strain of brook charr Salvelinus fontinalis as well as their reciprocal hybrids, were reared in a common environment and submitted to swimming tests combined with salinity challenges. The critical swimming speeds (U_crit ) of the different crosses were measured in both fresh (FW) and salt water (SW) and the variations in several physiological traits (osmotic, energetic and metabolic capacities) that are predicted to influence swimming performance were documented. Anadromous and resident fish reached the same U_crit in both FW and SW, with U_crit being 14% lower in SW compared with FW. The strains, however, seemed to use different underlying strategies: the anadromous strain relied on its streamlined body shape and higher osmoregulatory capacity, while the resident strain had greater citrate synthase (FW) and lactate dehydrogenase (FW, SW) capacity and either greater initial stores or more efficient use of liver (FW, SW) and muscle (FW) glycogen during exercise. Compared with R_♀ L_♂ hybrids, L_♀ R_♂ hybrids had a 20% lower swimming speed, which was associated with a 24% smaller cardio-somatic index and higher physiological costs. Thus swimming performance depends on cross direction (i.e. which parental line was used as dam or sire). The study thus suggests that divergent physiological factors between anadromous and resident S. fontinalis may result in similar swimming capacities that are adapted to their respective lifestyles.

Efficacy of needle-free injection on antibody production against Clostridium chauvoei in beef calves under field conditions

This study compared needle-free and needle-based injection devices for vaccination of calves against Clostridium chauvoei in warm and cold conditions. Both devices elicited comparable antibody responses in calves. Needle-free injection devices can be used to vaccinate calves provided appropriate precautions are taken in cold weather.

Evaluation of the effects of treating dairy cows with meloxicam at calving on retained fetal membranes risk

Some non-steroidal anti-inflammatory drugs increase the risk of retained fetal membranes. This is the first study to investigate the effects of meloxicam on the risk of retained fetal membranes. Administration of meloxicam to dairy cattle immediately following calving revealed no differences in the incidence of retained fetal membranes between meloxicam-treated and untreated animals. There was no difference between the 2 groups in the incidence of periparturient diseases following calving. Meloxicam can be used on the day of calving in lactating cows without increasing the risk of retained fetal membranes.

Imprisonment, alcohol dependence and risk of delusional disorder: a cross-sectional study

BACKGROUND

Compared to the general population, an excess of psychotic illnesses, major depression and dependence disorders among prisoners has been reported. However, the impact of prison on detainees' psychopathology has rarely been studied.

OBJECTIVE

To determine the mental disorders liable to develop or regress on entry into prison and over time.

METHOD

Two samples of French prisoners detained in local prisons were interviewed using the same methodology. The first sample consisted of 267 new arrivals. The second was a random sample of 450 prisoners. Diagnoses were assessed using a thorough methodology: each prisoner was interviewed for approximately 2 hours by two clinicians. One of the clinicians used a structured clinical interview, which generates DSM IV diagnoses (MINI plus v 5.0); the second completed the procedure with an open clinical interview. The final DSM IV diagnoses were obtained as a consensus between the two approaches. Multilevel logistic regressions were used to take into account potential confounders.

RESULTS

Prevalence rates of mental disorders were substantially higher in prison even for the sample of newcomers (major depression disorder: 24.7%, substance dependence: 17.6% and schizophrenia: 4.1%). Alcohol dependence disorder was significantly more frequent in the sample of newcomers (OR 1.84 [1.01-3.51]). No significant difference was evidenced between samples for substance dependence disorder. Psychotic disorders were significantly less frequent at entry into prison, particularly delusional disorder (OR 0.29 [0.08-0.98]).

CONCLUSION

This study shows the contrasted potential effects of prison on psychopathology: alcohol dependence disorders were significantly more frequent for the newcomers, while the frequency of delusional disorders was lower. This evidence is arguing in favour of the validity of the old concept: prison psychosis. Moreover, prisoners should receive relevant help from clinicians to cope with these disorders.

Production of flounder (Pleuronectiformes) in eastern North America: biological issues1This review is part of a virtual symposium on current topics in aquaculture of marine fish and shellfish

Flounders (Pleuronectiformes) from eastern North America have been extensively studied over the last few decades, and most of that work has been oriented towards different aspects related to fish production, i.e., aquaculture. However, aquaculture production has not progressed as it might have been expected. Flounders are omnivorous, euryhaline, inhabit shore habitats, and offer good potential for aquaculture diversification. They are found all along the eastern coast of Canada and the US, and different species occupy coastal habitats with some species overlapping in certain areas. Despite specific biological and ecological requirements for each species, the accumulated knowledge on breeding, larval rearing, juveniles, and stock enhancement creates a frame of reference that is often underestimated but that indicates a promising future for the production of these fishes.

Safety and efficacy of vaccination of seronegative bulls with modified-live, cytopathic bovine viral diarrhea viruses

The objectives were to vaccinate peri-pubertal bulls with a modified-live vaccine consisting of cytopathic BVDV strains Singer and 296 and evaluate the resulting: (a) transient shed of modified-live, cytopathic BVDV in semen; (b) risk of prolonged testicular infection; and (c) protection against subsequent testicular infection due to viral challenge. Seronegative, peri-pubertal bulls were vaccinated subcutaneously with a standard dose of vaccine (n=11) or were maintained as unvaccinated controls (n=11). Forty-nine days after vaccination, all bulls were intranasally inoculated with a noncytopathic field strain of BVDV. Semen and testicular biopsies collected after vaccination and challenge were assayed for BVDV using virus isolation, reverse transcription-nested PCR, or immunohistochemistry, and the identity of viral strains was determined by nucleotide sequencing of PCR products. Vaccination of peri-pubertal bulls with this vaccine caused a short-term, transient shed of only the type 1a strain of modified-live, cytopathic BVDV in semen for up to 10d after vaccination. The vaccine did not cause prolonged testicular infection. Vaccination with this product prevented development of prolonged testicular infections after subsequent exposure to a field strain of BVDV.

Family Characteristics and Children's Preschool Trajectories of Disruptive Behaviours

Aim:

The aim of this study was to investigate the association between parental characteristics and parental practices and the trajectories of Disruptive Behaviours (DBs) during early childhood.

Method:

Trajectories of DBs - Hyperactivity, Oppositional behaviour and Physical Aggression - were assessed based on annual mother interviews from 17 to 60 months for a Canadian population-representative birth cohort (N=2057).

Results:

Frequency of DBs increased from 17 to 41 months and then tended to decline. Parental characteristics and parental practices were both associated with chronic trajectories of DBs.

Conclusion:

Early childhood is a critical period to prevent later DBs during school years that leads to psychosocial maladjustment during adolescence and adulthood.

Adding to the controversy: pitfalls in the diagnosis of testosterone deficiency syndromes with questionnaires and biochemistry

PURPOSE

To determine the value of available questionnaires used for the diagnosis of testosterone deficiency syndromes (TDS) by correlating their ratings with a panel of hormonal determinations in a male population.

MATERIALS AND METHODS

Participants completed the ADAM questionnaire and underwent biochemical evaluation at the local site. Assessments determined entry into Group A (symptomatic) or Group B (non-symptomatic). After stratification, subjects provided a morning sample of blood, completed the Aging Male Survey (AMS) and the newly developed Canadian Society for the Study of the Aging Male (CSAM-Q) questionnaires. Serum aliquots were analysed at a central lab for 8 putative markers commonly associated with symptomatic testosterone deficiency associated with aging: total testosterone (T); bioavailable T (BT); dehydroepiandrosterone sulphate (DHEA-S); sex-hormone binding globulin (SHBG); luteinizing hormone (LH), prolactin (PRL); thyroid-stimulating hormone (TSH) and insulin-like growth factor-1 (IGF-1).

RESULTS

92 men were screened; of these 59 (mean age of 58+/-11 years) completed the study, 30 (51%) scored positively (mean 61.5 years) to the ADAM while 29 (49%) did not (mean 54.1 years). For the AMS the weight of the three domains (psychological, somato-vegetative and sexual) was significantly greater in Group A (p<0.001) than in Group B. Equally, for the CAS questionnaire, the scores for the variables energy, global performance, frequency of intercourse, mood and quality of sleep were lower in Group A than in their asymptomatic counterparts (p<0.001). The domain of memory assessment within the CSSAM-Q was not discriminatory. ADAM and AMS are self-administered and completed within 10 minutes. CSSAM-Q is more time consuming, requires an investigator to administer, and memory domain is biased in favour of specific professional training. No difference was found between the two groups in 6 of 8 biochemical tests. However, significant lower values (p<0.001) were found for DHEA-S and IGF-1 in the symptomatic group as compared with the non-symptomatic cohort.

CONCLUSIONS

This study confirms that newer, more complex tools perform similarly to the simpler ADAM questionnaire. The lack of correlation between the clinical picture and the most commonly used biochemical confirmatory tests, again, clearly points to the paramount importance of the clinical evaluation. An emphasis and reliance on serum T alone hinders the clinician's ability to manage testosterone deficiency syndromes (TDS).

Production effects of pathogens causing bovine leukosis, bovine viral diarrhea, paratuberculosis, and neosporosis

The primary purpose of this research was to determine associations among seropositivity for bovine leukemia virus (BLV), bovine viral diarrhea virus (BVDV), Mycobacterium avium ssp. paratuberculosis (MAP), and Neospora caninum (NC) and each of 3 outcome variables (305-d milk, fat, and protein production) in Canadian dairy cattle. Serum samples from up to 30 randomly selected cows from 342 herds on monthly milk testing were tested for antibodies against BLV (IDEXX ELISA; IDEXX Corporation, Westbrook, ME), MAP (IDEXX or Biocor ELISA; Biocor Animal Health, Inc., Omaha, NE), and NC (IDEXX or Biovet ELISA; Biovet Inc., St. Hyacinthe, Quebec, Canada). Up to 5 unvaccinated cattle over 6 mo of age were tested for virus-neutralizing antibodies to the Singer strain of type 1 BVDV. Dairy Herd Improvement records were obtained electronically for all sampled cows. Linear mixed models with herd and cow as random variables were fit, with significant restricted maximum likelihood estimates of outcome effects being obtained, while controlling for potential confounding variables. Bovine leukemia virus seropositivity was not associated with 305-d milk, 305-d fat, or 305-d protein production. Cows in BVDV-seropositive herds (at least one unvaccinated animal with a titer > or =1:64) had reductions in 305-d milk, fat, and protein of 368, 10.2, and 9.5 kg, respectively, compared with cows in BVDV-seronegative herds. Mycobacterium avium ssp. paratuberculosis seropositivity was associated with lower 305-d milk of 212 kg in 4+-lactation cows compared with MAP-seronegative 4+-lactation cows. Neospora caninum seropositivity in primiparous cows was associated with lower 305-d milk, fat, and protein of 158, 5.5, and 3.3 kg, respectively, compared with NC-seronegative primiparous cows. There were no interactions among seropositivity for any of the pathogens and their effects on any of the outcomes examined, although the low MAP seroprevalence limited this analysis. Results from this research will contribute to understanding the economic impacts of these pathogens and justify their control.

Rapid Fabrication and Chemical Patterning of Polymer Microstructures and their Applications as a Platform for Cell Cultures

Much of the current knowledge regarding biological processes has been obtained through in-vitro studies in bulk aqueous solutions or in conventional Petri-dishes, with neither methodology accurately duplicating the actual in-vivo biological processes. Recently, a number of innovative approaches have attempted to address these shortcomings by providing substrates with controlled features. In particular, tunable surface chemistries and topographical micro and nanostructures have been used as model systems to study the complex biological processes. We herein report a versatile and rapid fabrication method to produce a variety of microstructured polymer substrates with precise control and tailoring of their surface chemistries. A poly(dimethylsiloxane) (PDMS) substrate, produced by replication over a master mold with specific microstructures, is modified by a fluoro siloxane derivative to enhance its anti-adhesion characteristics and used as a secondary replication mold. A curable material, deposited by spin coating on various substrates, is stamped with the secondary mold and crosslinked. The removal of the secondary mold produces a microstructured surface with the same topographical features as the initial master mold. The facile chemical patterning of the microstructured substrates is demonstrated through the use of microcontact printing methods and these materials are tested as a platform to guide cell attachment, growth and proliferation. The master mold and flexible fluorinated PDMS stamps can be used in a repeated manner without any degradation of the anti-adhesion characteristics opening the way to the development of high-throughput fabrication methods that can yield reliable and inexpensive microstructured and chemically patterned substrates.

Étude paléolimnologique de l'histoire trophique du lac Saint-Charles, réservoir d'eau potable de la Communauté Urbaine de Québec

Cette étude utilise une approche paléolimnologique pour reconstituer l'histoire trophique du réservoir d'eau potable de la Communauté Urbaine de Québec (CUQ), le lac Saint-Charles. Ce lac manifeste présentement un manque d'oxygène près du fond à la fin de la stratification estivale et hivernale. L'étude révèle des changements dans la communauté diatomifère fossile depuis environ les 150 dernières années. L'événement ayant entraîné le plus de changements biologiques et physico-chimiques dans le bassin est la transformation hydrologique engendrée par la construction d'un barrage en 1934 qui éleva le niveau du lac d'environ 1,5 à 2 mètres. Par conséquent, il y eut des changements dans la structure des communautés de diatomées avec des effets sur le ratio espèces planctoniques / benthiques, sur la paléoproductivité et les caractéristiques physico-chimiques des sédiments suivant cette période. Les assemblages diatomifères indiquent que les conditions mésotrophes se sont maintenues pendant toute la période étudiée. L'analyse du phosphore total dans les sédiments et la reconstitution à partir des diatomées fossiles du phosphore total dans l'eau montrent une légère diminution de la concentration en phosphore avec le temps. Ces observations démontrent qu'il n'y a pas eu d'accélération du processus d'eutrophisation engendrée par les activités humaines. Par contre, l'analyse géochimique des sédiments révèle un apport plus important de métaux depuis la fin du 19e siècle, qui atteint un plateau vers la fin des années 70.

Selection against blue mussels (Mytilus edulis L.) homozygotes under various stressful conditions

Three mussel groups differing in mean multilocus heterozygosity (MLH) were used to examine the MLH-fitness relationship. Mussels were submitted to aerobic and anaerobic stressful conditions in the laboratory, and their LT(50) was measured. Mortality was not random in two of the three groups and affected the homozygous individuals more. This selective mortality caused a significant increase in the mean MLH of the survivors, but only for the two groups characterized by the lowest initial MLH and significant deficits in heterozygotes at the onset of the experiments. While these experiments were ongoing, the same two groups also suffered a 40% mortality rate in lantern nets under field conditions. This mortality also increased the mean MLH in survivors. All groups showed strong inverse relationships between MLH and standard metabolism. Our results suggest that the higher resistance of more heterozygous individuals is related to their lower metabolic needs.

Insulin-like growth factor binding proteins (IGFBPs) as potential physiological substrates for human kallikreins hK2 and hK3

Insulin-like growth factors (IGFs) are important growth regulators of both normal and malignant prostate cells. Their action is regulated by six insulin-like growth factor binding proteins (IGFBPs). The proteolytic cleavage of IGFBPs by various proteases decreases dramatically their affinity for their ligands and therefore enhances the bioavailability of IGFs. To elucidate the putative biological role of prostatic kallikreins hK2 and hK3 (prostate-specific antigen) in tumour progression, we analyzed the degradation of IGFBP-2, -3, -4 and -5 by these two tissue kallikreins. We found that hK3, already characterized as an IGFBP-3 degrading protease, cleaved IGFBP-4 but not IGFBP-2 and -5, whereas hK2 cleaved all of the IGFBPs much more effectively, and at concentrations far lower than those reported for other IGFBP-degrading proteases. The proteolytic patterns after cleavage of IGFBPs by hK2 and hK3 were similar and were not modified in the presence of IGF-I. Heparin, but not other glycosaminoglycans, enhanced dramatically the ability of hK3 but not hK2 to degrade IGFBP-3 and IGFBP-4. More importantly, the IGFBP fragments generated by hK2 and hK3 had no IGF-binding capacity, as assessed by Western ligand blotting. Our results suggest that the prostatic kallikreins hK2 and hK3 may influence specifically the tumoral growth of prostate cells through the degradation of IGFBPs, to increase IGF bioavailability.

Seroprevalence of infection with Mycobacterium avium subspecies paratuberculosis, bovine leukemia virus, and bovine viral diarrhea virus in maritime Canada dairy cattle

The purpose of this study was to survey the seroprevalence of infection with the agents of production-limiting diseases in dairy cattle in New Brunswick, Nova Scotia, and Prince Edward Island. In 30 randomly selected herds per province, 30 cattle per herd were randomly selected and tested for antibodies to bovine leukemia virus (BLV) and Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis), while 5 unvaccinated cattle over 6 months of age were tested for antibodies to bovine viral diarrhea virus (BVDV). For BLV, 20.8% (15.8% to 27.0%) of cows were positive, and 70.0% (60.3% to 79.7%) of herds had at least one positive cow. In BLV-positive herds, the average BLV prevalence was 30.9% (24.8% to 37.2%). For M. paratuberculosis, 2.6% (1.8% to 3.9%) of cows were positive, and 16.7% (8.8% to 24.5%) of herds had at least 2 M. paratuberculosis-positive cows. In M. paratuberculosis-positive herds, the average M. paratuberculosis prevalence was 8.5% (6.9% to 10.1%). For BVDV, 46.1% (35.5% to 56.7%) of herds had at least 1 BVDV-positive animal with a titer greater than or equal to 1:64.

Fetal biometric parameters, twin type and birth weight difference. A longitudinal study

OBJECTIVE

To examine the relationship between twin type, divided by zygosity, chorionicity, and birth weight difference [more or less than 15% intertwin weight difference at delivery] on fetal biometric measurements, including biparietal diameter, transverse abdominal diameter, head and abdominal circumferences (AC) and head and abdominal areas, femur length (FL), transverse cerebellar diameter, cerebellar circumference and cerebellar area at 18, 23, 28 and 32 weeks of gestational age.

STUDY DESIGN

A prospective and longitudinal study was done on 75 twin pairs that did not present the twin-twin transfusion syndrome (150 fetuses) divided into birth weight difference group I (<15%) and group II (>/=15%). The twin pairs were divided into three groups: dizygotic, monochorionic, and dichorionic-monozygotic. In each group the differences in various ultrasound indices were evaluated in reference to discordant growth or concordant growth.

RESULTS

In our sample, there were no monozygotic twin pairs with dichorionic placentation with a birth weight difference of more than 15%. Significant associations of group and gestational age were found in dizygotic and monochorionic twins. Intrapair differences were significantly higher in group II (>/=15%) than in group I (<15%) for all fetal parameters studied except for AC, abdominal area and all cerebellar parameters. The value of these discrepancies increased according to gestational age except for FL. Significant interactions between group and zygosity type indicated that intrapair FL differences were more associated with group in monochorionic twins, whereas intrapair transverse cerebellar diameter differences were more associated with group in dizygotic twins.

CONCLUSION

Our data show that most fetal biometric parameters are associated with birth weight discordancy. Abdominal area could be a relevant marker for twins with obstetric complications. Note that this is the first research that has studied a twin sample divided by both twin type and birth weight group.

Veno-venous continuous renal replacement therapy for burned patients with acute renal failure

From 1995 to 1998, 12 burned patients with acute renal failure (ARF) were treated by veno-venous continuous renal replacement therapy (CRRT) at the Burn Unit of Hôtel-Dieu de Montréal. Their mean (+/-SD) age was 51+/-12 years, and the mean burned surface covered 48.6+/-15.8% of total body surface area. All patients were mechanically ventilated and presented evidence of sepsis. The mean delay before occurrence of ARF was 15+/-6 days and ARF was mainly related to sepsis and hypotension. Main reasons for CRRT initiation were azotemia and fluid overload. A total of 15 CRRT modalities were applied (12 continuous veno-venous hemodiafiltration, CVVHDF; two continuous veno-venous hemofiltration, CVVH; and one continuous veno-venous hemodialysis, CVVHD) over 14+/-13 days. For CRRT, nine patients received heparin and three were not anticoagulated. Mean values for dialysate and reinjection flow rates were 1134+/-250 ml/h and 635+/-327 ml/h, respectively. Admission weight was 78.8+/-12.7 kg with a mean weight gain before CRRT initiation of 10.0+/-5.8 kg and a mean weight loss during CRRT of 8.9+/-5.5 kg. Nine patients received enteral plus parenteral nutrition, and three, parenteral nutrition only; the total caloric intake was 31.5+/-7.0 kcal/kg/day and protein intake, 1.8+/-0.4 g/kg/day. The normalized protein catabolic rate (nPCR) was evaluated at 2.28+/-0.78 g/kg/day during CRRT. The mortality rate was 50%. The six survivors all recovered normal renal function with four of them requiring intermittent hemodialysis for short periods. In conclusion, veno-venous CRRT is particularly well suited for this selected population allowing smooth fluid removal and aggressive nutritional support.

Transient NMDA receptor inactivation provides long-term protection to cultured cortical neurons from a variety of death signals

NMDA receptor antagonists, such as (+)-5-methyl-10, 11-dihydro-5H-dibenzo [a,d] cyclohepten-5,10-imine maleate (MK-801), potently block glutamate-induced neuronal death in myriad in vitro cell models and effectively attenuate ischemic damage in vivo. In this report, a novel role for MK-801 and other NMDA receptor antagonists in preconditioning neurons to withstand a wide range of subsequent lethal insults is described. A brief 30 min exposure to 0.1 microM MK-801, applied up to 96 hr before a "lethal" insult, protected primary cortical neurons from a diverse group of neurotoxic agents, including NMDA, beta-amyloid, staurosporine, etoposide, and oxygen-glucose deprivation. This neuroprotective preconditioning by MK-801 arose from transient NMDA receptor inactivation, because the noncompetitive NMDA receptor antagonists memantine and nylindin and the competitive antagonist AP-5 gave similar effects. MK-801 protection was dependent on new protein synthesis during the first 2 hr, but not from 2 to 5 hr, after MK-801 exposure. The MK-801 transient did not alter the ability of NMDA to trigger normally lethal [Ca(2+)](i) influx 48 hr later, but it did block early downstream signaling events coupled to NMDA neurotoxicity, including PKC inactivation and the activation of calpain. Moreover, MK-801 protected neurons from staurosporine-induced apoptosis, although caspase activation in these cells was unimpeded. It is likely that the stress associated with transient inactivation of NMDA receptors triggered a rapid compensatory survival response that provided long-term protection from a spectrum of insults, inducing apoptotic and nonapoptotic death. The possibility that MK-801 preconditioning blocks an event common to seemingly diverse death mechanisms suggests it will be an important tool for obtaining a clearer understanding of the salient molecular events at work in neuronal death and survival pathways.

Hyperhomocysteinemia in hemodialysis patients: effects of 12-month supplementation with hydrosoluble vitamins

BACKGROUND

High-efficiency hemodialysis may induce a deficiency in hydrosoluble vitamins. Supplementation with B-complex vitamins has been shown to lower serum homocysteine concentrations in several groups, but relatively few studies have concerned hemodialysis patients. Our objectives were to determine the status in B-complex vitamins in a large cohort of unsupplemented hemodialysis patients and to assess the effects of supplementation with hydrosoluble vitamins on serum homocysteine over one year.

METHODS

Serum total homocysteine (tHcy), vitamin B12, folate, pyridoxal-5'-phosphate (P-5'-P; the active moiety of vitamin B6), as well as red blood cell folate concentrations, were measured in 168 chronic dialysis patients on three times weekly high-efficiency hemodialysis and not supplemented with hydrosoluble vitamins. Their methylenetetrahydrofolate reductase C677T (MTHFR) genotypes were also determined (homozygotes TT, heterozygotes CT, without mutation CC). All involved patients were then supplemented with hydrosoluble vitamins (once daily by mouth, DiaVite; R&D Laboratories, Minneapolis, MN, USA), and half of them were randomized to receive in addition 10 mg intravenously of folic acid posthemodialysis (30 mg intravenously per week). Serum tHcy was monitored after 6 and 12 months of supplementation in the 140 and 128 patients available for follow-up.

RESULTS

At baseline, serum and red blood cell folate concentrations were within normal limits in all patients except for two with borderline serum folate (mean values of 21 +/- 8 and 1195 +/- 454 nmol/L), whereas serum vitamin B12 and P-5'-P were below normal in 11 and 65 patients, respectively (mean values of 327 +/- 215 pmol/L and 19 +/- 16 nmol/L for the 168 patients). Initial tHcy levels were increased in all patients (mean 33.3 +/- 16.6 for a normal below 11.8 +/- 1.5 micromol/L); tHcy significantly decreased to 23.5 +/- 7.6 micromol/L after six months (P < 0.0001 vs. baseline) and to 21.7 +/- 6.1 micromol/L after 12 months (P < 0.0001 vs. baseline) for the entire group, but was normalized in only four patients at 12 months. After six months, the mean reduction in tHcy was slightly but significantly greater for patients receiving intravenous folic acid (12.2 +/- 18.5 micromol/L) compared with patients not receiving it (8.3 +/- 9.8 micromol/L, P < 0.05). However, at 12 months, no difference between both subgroups persisted. When considering the different genotypes, tHcy at baseline tended to be higher for TT than CT and CC (39.8 +/- 30.9 vs. 31.4 +/- 10.5 vs. 31.6 +/- 11.8 micromol/L) and decreased to respective values of 21.1 +/- 6.9 versus 21.4 +/- 6.1 versus 22.2 +/- 5.9 micromol/L at 12 months. The impact of the addition of folic acid to DiaVite appeared particularly significant in TT patients at six months.

CONCLUSIONS

(1) Hyperhomocysteinemia was present in 100% of our hemodialysis patients. (2) Nearly 40% of our unsupplemented hemodialysis patients were deficient in vitamin B6. (3) Supplementation with DiaVite(R) has resulted in significant tHcy reductions for all three genotypes. (4) The impact of the proposed supplementation protocol was found after six months and was maintained, but did not increase further after 12 months of the same regimen. (5) The addition of intravenous folic acid has been associated with a more pronounced decrease in tHcy in TT patients.

Pharmacological and molecular characterization of glutamate receptors in the MIN6 pancreatic beta-cell line

The MIN6 pancreatic beta-cell line responds to glutamate, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate, but not N-methyl-D-aspartate (NMDA) or 1S,3R-trans-ACPD, with increases in [Ca2+]i. This correlates with MIN6 expression of AMPA receptor subunits (GluR1-4) but only weak expression of NMDA NR2 receptor subunits, as determined by reverse transcriptase polymerase chain reaction (RT-PCR). Pharmacological characterization of the MIN6 AMPA receptors showed that AMPA-triggered [Ca2+]i responses were blocked by GYKI 52466, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and pentobarbital. AMPA-triggered [Ca2+]i responses were also blocked in Na(+)-free medium and by the voltage-sensitive Ca2+ channel antagonist La3+. Unlike cortical neuronal cultures, which show a loss of membrane-associated protein kinase C (PKC) activity and die in response to excitatory amino acid exposure, glutamate was not toxic to MIN6 cells and it did not decrease PKC activity. These studies indicate that MIN6 cells possess Ca(2+)-impermeable AMPA receptors that secondarily allow Ca2+ influx following AMPA-induced depolarization and that, despite elevating [Ca2+]i, AMPA is not toxic to these cells. The effects of glutamate and glutamate receptor antagonists on pancreatic cells needs to be better understood if these compounds are to be used as therapeutic agents to treat stroke.

AR-R15896AR blocks the early NMDA-induced loss of MAP2 in primary cortical cultures

The low-affinity use-dependent N-methyl-D-aspartate (NMDA) receptor antagonist AR-R15896AR is neuroprotective in primary rat cortical cultures exposed to toxic concentrations of NMDA and reduces the magnitude of NMDA-triggered increases in [Ca2+]i. Here we show using fluorescence staining and measurements of microtubule-associated protein-2 (MAP2) levels, that AR-R15896AR inhibits the NMDA-induced loss of MAP2 that occurs within 2 min following NMDA exposure. Understanding the multiple, Ca(2+)-triggered intracellular events that occur following NMDA receptor stimulation is important to the development of safe and effective neuroprotective agents.

Factors associated with being a bovine-virus diarrhoea (BVD) seropositive dairy herd in the Møre and Romsdal County of Norway

Factors associated with being a bovine-virus diarrhoea (BVD) seropositive dairy herd were studied in a case-control study of 314 dairy herds in the Møre and Romsdal County of Norway. Information was collected through a mailed questionnaire, and associations were modeled using conditional logistic regression after selecting variables by a best-subset procedure. Purchasing of animals, use of common pasture, herd-to-herd contact over pasture fences, purchasing cattle with insufficient health (about BVD) documentation, and not using dairy advisors were associated with higher risk. In addition, younger farmers were more likely to have a bovine-virus diarrhoea seropositive herd than older farmers. 'Other animal traffic', including use of common animal housing in the summer months and exchange of calves between farmers were also risk factors. Collectively, these factors could explain 51% of the seropositive herds.

Evidence that brain-derived neurotrophic factor neuroprotection is linked to its ability to reverse the NMDA-induced inactivation of protein kinase C in cortical neurons

Several lines of evidence indicate that a rapid loss of neuronal protein kinase C (PKC) activity is a characteristic feature of cerebral ischemia and is a necessary step in the NMDA-induced death of cultured neurons. Exposing embryonic day 18 primary rat cortical neurons to 50 microM NMDA or 50 microM glutamate for 10 min caused approximately 80% cell death over the next 24 h, but excitotoxic death was largely averted, i.e., by 70-80%, in cells pretreated with brain-derived neurotrophic factor (BDNF). An 8-h preexposure to BDNF (50-100 ng/ml) maximally protected cortical cells from the effects of NMDA and glutamate, although the transient application of BDNF between 8 and 4 h before NMDA was equally protective. These effects of BDNF were abolished at supralethal, i.e., >100 microM, NMDA concentrations. It is significant that BDNF pretreatment prevented the inactivation of PKC in cortical cells normally seen 30 min to 2 h following lethal NMDA or glutamate exposure. This BDNF effect did not arise from changes in NMDA channel activity because neither whole-cell NMDA current amplitudes nor increases in intracellular free Ca2+ concentration were altered by the 8-h BDNF pretreatment. Furthermore, BDNF offered no neuroprotection to cells treated with the PKC inhibitors staurosporine (10-20 nM), calphostin C (1-2.5 microM), or GF-109203X (100 nM) at the time of NMDA addition. These results underscore the importance of PKC inactivation in glutamate-induced neuronal death. They also suggest that BDNF neuroprotection arises, at least in part, via its ability to block the mechanism by which pathophysiological Ca2+ influx through the NMDA receptor causes membrane PKC inactivation.

Comparison of the changes in protein kinase C induced by glutamate in primary cortical neurons and by in vivo cerebral ischaemia

Changes in protein kinase C (PKC) were compared in primary cortical neurons exposed to glutamate and in the CA-1 hippocampal region of rats subjected to transient cerebral ischaemia. After a 15-min exposure of cortical neurons to excitotoxic levels of glutamate, a 50-60% loss of membrane PKC activity but only about a 20% loss in the amount of enzyme was observed, suggesting that in addition to enzyme loss other mechanisms also contributed to the overall loss of membrane PKC activity. Glutamate induced a 25-40% decrease in immunodetectable levels of PKC alpha, beta, gamma, and lambda but no detectable changes in PCK epsilon and zeta. The loss of PKC activity coincided with a shift in electrophoretic mobility of PKC gamma, epsilon, and lambda, but not of PKC alpha, beta, or zeta, suggesting post-translational modification of some PKC isoforms. By comparison, in rats subjected to transient (15-min) global ischaemia, a similar 50-60% decrease in membrane PKC activity, a 20-25% loss in the amount of PKC, and a shift in PKC mobility were observed in CA-1 neurons 6 h post-reperfusion. In both the in vivo and the in vitro "ischaemic" models, administration of the AMPA receptor antagonist NBQX prevented the loss of PKC activity. These results indicate that the loss of PKC observed in in vivo ischaemia is likely to be due to excitotoxic damage and that this event can be closely mirrored in primary neuronal cultures damaged by glutamate.

Severe acute bovine viral diarrhea in Ontario, 1993-1995

In 1993, noncytopathic bovine viral diarrhea virus (BVDV) strains with enhanced virulence caused unprecedented outbreaks of severe acute bovine viral diarrhea (BVD) in dairy, beef, and veal herds in Ontario (Canada). Fever, pneumonia, diarrhea, and sudden death occurred in all age groups of cattle. Abortions often occurred in pregnant animals. Gross lesions in the alimentary tract were similar to those associated with mucosal disease, especially in animals >6 months of age. Cattle of all age groups had microscopic lesions in the alimentary tract similar to those seen with mucosal disease. The epidemic peaked in the summer of 1993, with 15% of all bovine accessions from diseased cattle presented to the diagnostic laboratory being associated with BVDV. The virus strains involved in the outbreak were analyzed using monoclonal and polyclonal antibodies and the polymerase chain reaction. The virus isolates from these outbreaks of severe disease were determined to be type 2 BVDV. Type 2 BVDV has been present in Ontario at least since 1981 without causing widespread outbreaks of severe acute BVD, which suggests that type 2 designation in itself does not imply enhanced virulence. Cattle properly vaccinated with type 1 BVDV vaccines appear to be protected from clinical disease.

[Prevalence of positive tuberculin test in a population of patients requiring long-term care in a hospital setting]

OBJECTIVE

To determine the prevalence of positive tuberculin tests in a population of patients requiring long-term care in a hospital setting.

DESIGN

Prevalence study: to evaluate reaction to the test among patients who agreed to be included in the study.

SETTING

The study took place in two units of the Enfant-Jésus hospital where patients are admitted for chronic care.

PARTICIPANTS

A total of 108 patients were eligible for the study; 56 agreed to take part. One patient died before the study was completed.

INTERVENTIONS

The tuberculin test consisted of an injection of PPD-T and reading the reaction 48 to 78 hours later. A reaction > 10 mm was considered significant. Patients with insignificant reactions were injected again 2 weeks later in order to evaluate positive response secondary to reactivation of the immune system (booster effect).

MAIN OUTCOME MEASURES

Indications of previous tuberculosis, risk factors for tuberculosis, immunosuppressive medication, length of stay in hospital, size of reaction.

RESULTS

Seventeen tuberculin tests were positive (30.9%); of these, six were positive after the second injection.

CONCLUSION

The prevalence of positive tuberculin tests was high in our elderly population; this finding is comparable to the findings of American studies.

Evidence that the early loss of membrane protein kinase C is a necessary step in the excitatory amino acid-induced death of primary cortical neurons

A rapid loss of protein kinase C (PKC) activity is a prognostic feature of the lethal damage inflicted on neurons by cerebral ischemia in vivo and by hypoxic and excitotoxic insults in vitro. However, it is not known if this inactivation of PKC is incidental or is an essential part of the neurodegenerative process driven by such insults. To address this issue, the effects of glutamate on PKC activity and neurotoxicity were studied in immature [8 days in vitro (DIV)] and mature (15-20 DIV) embryonic day 18 rat cortical neuronal cultures. Exposing 16 DIV neurons to as little as 20-50 microM glutamate for 15 min was neurotoxic and induced a rapid (approximately 1-2 h) Ca(2+)-dependent inactivation of membrane PKC. By contrast, neurons 8 DIV were resistant to > 800 microM glutamate, and no evidence of PKC inactivation was observed. Reverse transcription-polymerase chain reaction analysis of NMDA and AMPA receptor subtypes and fluorometric intracellular Ca2- concentration measurements of the effects of NMDA, AMPA, kainate, and metabotropic glutamate receptor activation demonstrated that this striking difference in vulnerability was not due to an absence of functional glutamate receptors on neurons 8 DIV. However, 8 DIV neurons became highly vulnerable to low (< 20 microM) concentrations of glutamate when PKC activity was inhibited by 50 nM staurosporine, 1 microM calphostin C, 5 microM chelerythrine, or chronic exposure to 100 nM PMA. A 15-min coapplication of 50 nM staurosporine with glutamate, NMDA, AMPA, or kainate killed between 50 and 80% of 8 DIV cells within the ensuing 24 h. Moreover, cell death was observed in these cells even when PKC inactivation was delayed up to 4 h after glutamate removal. The evidence indicates that a loss of PKC activity is an essential element of the excitotoxic death of neurons 8 DIV and that cellular event(s) responsible for linking glutamate-mediated Ca2+ influx to PKC inactivation in vulnerable neurons 16 DIV are undeveloped in resistant cells 8 DIV. These results also suggest that the loss of neuronal PKC activity observed in cerebral ischemia may indeed be an important part of the neurodegenerative process. The 8 DIV/16 DIV cortical cell model may prove to be valuable in discerning those intracellular signaling events critical to glutamate-mediated neuronal death.