Heat stress in a temperate climate leads to adapted sensor-based behavioral patterns of dairy cows

Most research on heat stress has focused on (sub)tropical climates. The effects of higher ambient temperatures on the daily behavior of dairy cows in a maritime and temperate climate are less studied. With this retrospective observational study, we address that gap by associating the daily time budgets of dairy cows in the Netherlands with daily temperature and temperature-humidity index (THI) variables. During a period of 4 years, cows on 8 commercial dairy farms in the Netherlands were equipped with neck and leg sensors to collect data from 4,345 cow lactations regarding their daily time budget. The time spent eating, ruminating, lying, standing, and walking was recorded. Individual cow data were divided into 3 data sets: (1) lactating cows from 5 farms with a conventional milking system (CMS) and pasture access, (2) lactating cows from 3 farms with an automatic milking system (AMS) without pasture access, and (3) dry cows from all 8 farms. Hourly environment temperature and relative humidity data from the nearest weather station of the Dutch National Weather Service was used for THI calculation for each farm. Based on heat stress thresholds from previous studies, daily mean temperatures were grouped into 7 categories: 0 = (<0°C), 1 = (0-12°C, reference category), 2 = (12-16°C), 3 = (16-20°C), 4 = (20-24°C), 5 = (24-28°C), and 6 = (≥28°C). Temperature-humidity index values were grouped as follows: 0 = (THI <30), 1 = (THI 30-56, reference category), 2 = (THI 56-60), 3 = (THI 60-64), 4 = (THI 64-68), 5 = (THI 68-72) and 6 = (THI ≥72). To associate daily mean temperature and THI with sensor-based behavioral parameters of dry cows and of lactating cows from AMS and CMS farms, we used generalized linear mixed models. In addition, associations between sensor data and other climate variables, such as daily maximum and minimum temperature, and THI were analyzed. On the warmest days, eating time decreased in the CMS group by 92 min/d, in the AMS group by 87 min/d, and in the dry group by 75 min/d compared with the reference category. Lying time decreased in the CMS group by 36 min/d, in the AMS group by 56 min/d, and in the dry group by 33 min/d. Adaptation to daily temperature and THI was already noticeable from a mean temperature of 12°C or a mean THI of 56 or above, when dairy cows started spending less time lying and eating and spent more time standing. Further, rumination time decreased, although only in dry cows and cows on AMS farms. With higher values for daily mean THI and temperature, walking time decreased as well. These patterns were very similar for temperature and THI variables. These results show that dairy cows in temperate climates begin to adapt their behavior at a relatively low mean environmental temperature or THI. In the temperate maritime climate of the Netherlands, our results indicate that daily mean temperature suffices to study the effects of behavioral adaptation to heat stress in dairy cows.

Highly selective detection of methanol over ethanol by a handheld gas sensor

Methanol poisoning causes blindness, organ failure or even death when recognized too late. Currently, there is no methanol detector for quick diagnosis by breath analysis or for screening of laced beverages. Typically, chemical sensors cannot distinguish methanol from the much higher ethanol background. Here, we present an inexpensive and handheld sensor for highly selective methanol detection. It consists of a separation column (Tenax) separating methanol from interferants like ethanol, acetone or hydrogen, as in gas chromatography, and a chemoresistive gas sensor (Pd-doped SnO2 nanoparticles) to quantify the methanol concentration. This way, methanol is measured within 2 min from 1 to 1000 ppm without interference of much higher ethanol levels (up to 62,000 ppm). As a proof-of-concept, we reliably measure methanol concentrations in spiked breath samples and liquor. This could enable the realization of highly selective sensors in emerging applications such as breath analysis or air quality monitoring.

Response to a Salmonella Enteritidis challenge in old laying hens with different vaccination histories

Extending the laying period of laying hens is beneficial for economic and sustainability purposes. Because vaccines were designed with a shorter laying period envisaged, it is unclear whether current Salmonella vaccines can provide sufficient levels of protection against infection at an older age. The purpose of this experiment was to determine the efficacy of early rearing vaccination schemes against Salmonella challenge late in the laying period. There were four treatment groups: birds that had not been vaccinated (Group 1), birds vaccinated with live Salmonella Enteritidis (SE) (Group 2), with live and inactivated SE (Group 3), or with live SE and live Salmonella Typhimurium (Group 4). At the end of the laying period, the birds were transported from the laying farm to the research facility where they were orally challenged with 2.06 × 109 colony-forming units SE at around 82 wk of age. Hens were euthanized and bacteriology was performed on cecum, liver, spleen, and follicular fluid samples to determine SE colonization 7 and 14 d after challenge. Clinical and bacteriological findings of hens vaccinated with different vaccination schemes and the non-vaccinated control group were compared. No significant differences in SE colonization were found for vaccinated groups compared to the non-vaccinated control group. This may be a result of waning immunity due to the long time between vaccination and challenge. Also, as vaccination took place in the rearing period in the field, initial levels of immunity may not have been optimal due to shortcomings in the vaccination technique. Furthermore, the results of this study may have been affected by differences in age, breed, and origin between the groups. Therefore, controlled studies from early age onwards are necessary for more accurate comparisons between vaccines.

The preventive effects of two nutraceuticals on experimentally induced acute synovitis

BACKGROUND

Nutraceuticals are often used in the management of equine osteoarthritis, but scientific evidence of their efficacy is lacking.

OBJECTIVES

To study the preventive effects of two new nutraceuticals after the experimental induction of synovitis in comparison with positive and negative control treatments.

STUDY DESIGN

Blinded, controlled, randomised experiment.

METHODS

Twenty-four healthy Standardbred horses were randomly allocated to supplement AT (multi-ingredient, 28 days), supplement HP (collagen hydrolysate, 60 days), meloxicam (4 days) or placebo (60 days). Synovitis was induced in the right intercarpal joint by intra-articular injection of 0.5 ng lipopolysaccharide (LPS) of Escherichia coli while treatments were continued. Blood and synovial fluid were sampled before treatment, immediately prior to LPS injection, and at 8, 24 and 48 h post-injection. Synovial fluid samples were analysed for total nucleated cell count (TNCC), total protein (TP) and selected biomarkers (prostaglandin E₂ [PGE₂ ], interleukin-6 [IL-6], glycosaminoglycans [GAGs], type II collagen synthesis [CPII], matrix metalloproteinase [MMP]). Lameness was scored by visual examination and pressure plate analysis immediately prior to LPS injection, and at 8, 24 and 48 h post-injection. Clinical examinations were performed before treatment, immediately prior to LPS injection, at 2, 4 and 6 h post-injection, and then twice per day during the test period.

RESULTS

Before treatment and intra-articular challenge, there were no statistically significant differences among the treatment groups for any of the parameters. After intra-articular challenge, the placebo group showed significantly higher synovial fluid TP, TNCC and PGE₂ compared with the meloxicam group, although the model did not induce a relevant amount of lameness. Both nutraceuticals resulted in significantly lower synovial fluid TP, TNCC and PGE₂ compared with placebo. No statistical differences in IL-6, GAGs, CPII or MMPs were observed among treatment groups. No adverse effects were observed.

MAIN LIMITATIONS

Despite evidence of synovitis, lameness was too mild to detect.

CONCLUSIONS

The preventive administration of these nutraceuticals showed anti-inflammatory effects in this validated synovitis model. Therefore, further studies of their clinical applicability are warranted.

Longitudinal study of udder cleft dermatitis in 5 Dutch dairy cattle herds

Udder cleft dermatitis (UCD) is a skin lesion in dairy cows, most often located between anterior parts of the udder and abdomen, but also found between the front quarters. A few recent studies have investigated the prevalence of UCD, but relatively little is known about its pathogenesis, clinical course, and duration. Therefore, the aim of this study was to investigate the incidence and recovery of UCD on high-prevalence herds. Five Dutch dairy herds with a UCD prevalence of at least 6% were visited weekly for 19 wk, followed by visits every other week for 26 wk. During each visit, all dry and lactating cows were inspected for the presence of UCD signs. If a UCD case was detected, the affected skin was photographed and the photo was subsequently examined by a research assistant. Cows were then classified according to the appearance of the skin into 3 categories: healthy (no photo: no signs), mild (photo: affected skin but no wound), or severe (photo: open wound). The overall mean within-herd prevalence of UCD was 38% and the overall mean incidence was 1.94 UCD episodes per 100 cow-weeks at risk. Incidence of UCD was significantly higher in cows in third or higher parity and significantly increased with DIM. Median observed duration of UCD was 16 wk. The UCD recovery was 3 times more likely for mild than for severe lesions. The probability of moving from one category to another between 2 consecutive visits was very low, indicating that rapid changes in appearance did not occur. The observed incidence of UCD was rather low, and the relatively high prevalence in the selected herds was most likely due to the long duration of lesions rather than a high incidence of new UCD cases.

Western Pacific Regional Green Light Committee: progress and way forward

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The Western Pacific Regional Green Light Committee (rGLC WPR) was established in 2011 to promote scale-up of programmatic management of drug-resistant tuberculosis (PMDT).

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rGLC WPR has generated greater awareness of regional challenges and has encouraged local solutions to regional problems.

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PMDT should be part and parcel of routine TB programme activity.

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Challenges and bottlenecks have varied according to the different stages of PMDT implementation, requiring different types of technical assistance.

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Regional initiatives should be dynamic and responsive to the needs of countries.

The Western Pacific Regional Green Light Committee (rGLC WPR) was established in 2011 to promote the rational scale-up of programmatic management of drug-resistant tuberculosis (PMDT). We reflect on its achievements, consider the challenges faced, and explore its potential future role. Achievements include the supervision and support of national PMDT action plans, increased local ownership, contextualized guidance, and a strong focus on regional capacity building, as well as a greater awareness of regional challenges. Future rGLC activities should include (1) advocacy for high-level political commitment; (2) monitoring, evaluation, and supervision; (3) technical support and contextualized guidance; and (4) training, capacity building, and operational research. Regional activities require close collaboration with both national and global efforts, and should be an important component of the new Global Drug-resistant TB Initiative.

Transmission of Actinobacillus pleuropneumoniae among weaned piglets on endemically infected farms

Clinical outbreaks due to Actinobacillus pleuropneumoniae occur recurrently, despite the wide-scale use of antimicrobials or vaccination. Therefore, new approaches for the prevention and control of these outbreaks are necessary. For the development of alternative measures, more insight into the transmission of the bacterium on farms is necessary. The aim of this cohort study was to quantify transmission of A. pleuropneumoniae amongst weaned piglets on farms. We investigated three possible transmission routes: (i) indirect transmission by infected piglets within the same compartment, (ii) transmission by infected pigs in adjacent pens and (iii) transmission by direct contact within pens. Additionally, we evaluated the effect of independent litter characteristics on the probability of infection. Two farms participated in our study. Serum and tonsil brush samples were collected from sows pre-farrowing. Serum was analysed for antibodies against Apx toxins and Omp. Subsequently, tonsil brush samples were collected from all piglets from these dams (N=542) in three cohorts, 3 days before weaning and 6 weeks later. Tonsil samples were analysed by qPCR for the presence of the apxIVA gene of A. pleuropneumoniae. Before weaning, 25% of the piglets tested positive; 6 weeks later 47% tested positive. Regression and stochastic transmission models were used to assess the contribution of each of the three transmission routes and to estimate transmission rates. Transmission between piglets in adjacent pens did not differ significantly from that between non-adjacent pens. The transmission rate across pens was estimated to be 0.0058 day(-1) (95% CI: 0.0030-0.010), whereas the transmission rate within pens was ten times higher 0.059 day(-1) (95% CI: 0.048-0.072). Subsequently, the effects of parity and serological response of the dam and litter age at weaning on the probability of infection of pigs were evaluated by including these into the regression model. A higher dam ApxII antibody level was associated with a lower probability of infection of the pig after weaning; age at weaning was associated with a higher probability of infection of the pig after weaning. Finally, transmission rate estimates were used in a scenario study in which the litters within a compartment were mixed across pens at weaning instead of raising litter mates together in a pen. The results showed that the proportion of infected piglets increased to 69% if litters were mixed at weaning, indicating that farm management measures may affect spread of A. pleuropneumoniae.

Local ischaemia does not influence anastomotic healing: an experimental study

The role of local ischaemia in the pathogenesis of colorectal anastomotic leakage (AL) is not known. This study investigates the role of local ischaemia caused by sutures in an experimental colonic anastomosis model. 36 mice were assigned to three types of anastomosis, all using running sutures; in the first group 5 stitches were used, in the second group 12 stitches were used, and in the third group at least 30 stitches were used. After 7 days the mice were re-operated, signs of AL were scored, and coronal sections of the anastomosis were histologically analyzed. The distribution of weight was not significantly different between the three groups. Mortality was 44% and not significantly different between the groups (group 1: 5/12, group 2: 4/12, and group 3: 7/12, p = 0.72). Faecal and purulent AL were observed in 6 animals in group 1, 2 in group 2, and 3 in group 3 (group 1: 50%, group 2: 17%, and group 3: 25%, p = 0.19). The distance between the two colonic edges (group 1: 0.51 μm, group 2: 1.34 μm, and group 3: 0.53 μm, p = 0.18), the diameter of the lumen at the site of the anastomosis (group 1: 2.92 μm, group 2: 4.06 μm, and group 3: 3.2 μm, p = 0.9), and the largest diameter of the lumen proximally to the anastomosis (group 1: 2.05 μm, group 2: 3.1 μm, and group 3: 2.6 μm, p = 0.25) were not different between the groups. Histological parameters of wound healing were not significantly different for the three groups. In this study no macroscopic and microscopic differences were observed between colon anastomosis with 5 stitches versus 12 and >30 stitches. This might indicate that local ischaemia does not negatively influence colonic wound healing.

Heart rate, heart rate variability and behaviour of horses during air transport

Heart rate (HR), HR variability (HRV) and behaviour score (BS) of nine horses were evaluated during an eight-hour air transport between The Netherlands and New York. HR and HRV parameters were calculated every five minutes during the air transport. Compared with transit (40±3), mean HRs were higher during loading into the jet stall (67±21, P<0.001), loading into the aircraft (47±6, P=0.011), taxiing (50±8, P=0.001), and during periods of in-flight turbulence (46±7, P=0.017). During the flight, individual horses showed differences in mean HR (P=0.005) and peak HR (P<0.001). By contrast with HR data, HRV data did not differ between stages or horses. BS was highest during turbulence (3.2±0.4). However, behaviour did not always correspond with HR measurements: the least responsive horse had the highest HR. Loading into the jet stall caused the highest increase in HR and was considered the most stressful event. During transit, HR was generally comparable with resting rates. Previous studies have shown that loading and transporting by road caused more elevation in HR than during loading and transporting by air. HRV data were not found to be useful, and caution is needed when interpreting HRV data. Not every horse exhibited stress through visible (evasive) behaviour, and HR measurements may provide an additional tool to assess stress in horses.

The influence of cow factors on the incidence of clinical mastitis in dairy cows

Many cow-specific risk factors for clinical mastitis (CM) are known. Other studies have analyzed these risk factors separately or only analyzed a limited number of risk factors simultaneously. The goal of this study was to determine the influence of cow factors on the incidence rate of CM (IRCM) with all cow factors in one multivariate model. Also, using a similar approach, the probability of whether a CM case is caused by gram-positive or gram-negative pathogens was calculated. Data were used from 274 Dutch dairy herds that recorded CM over an 18-mo period. The final dataset contained information on 28,137 lactations of 22,860 cows of different parities. In total 5,363 CM cases were recorded, but only 2,525 CM cases could be classified as gram-positive or gram-negative. The cow factors parity, lactation stage, season of the year, information on SCC from monthly test-day records, and CM history were included in the logistic regression analysis. Separate analyses were performed for heifers and multiparous cows in both the first month of lactation and from the second month of lactation onward. For investigating whether CM was caused by gram-positive or gram-negative pathogens, quarter position was included in the logistic regression analysis as well. The IRCM differed considerably among cows, ranging between 0.0002 and 0.0074 per cow-day at risk for specific cows depending on cow factors. In particular, previous CM cases, SCC in the previous month, and mean SCC in the previous lactation increased the IRCM in the current month of lactation. Results indicate that it is difficult to distinguish between gram-positive and gram-negative CM cases based on cow factors alone.

Is there an increased risk of TB relapse in patients treated with fixed-dose combination drugs in Indonesia?

SETTING

South Sulawesi Province, Republic of Indonesia.

OBJECTIVE

To compare relapse rates among tuberculosis (TB) patients treated with fixed-dose combination drugs (FDCs) and patients treated with the same regimen using loose drugs.

METHODOLOGY

Between 1999 and 2001, new smear-positive TB patients were randomly allocated to treatment with four-drug FDCs or loose drugs to study differences in treatment outcomes. Although it was not in the original study design, in 2004-2005 we performed a follow-up study by home visit of cured patients. We conducted an interview and tried to collect a sputum sample from each patient. If the patient was absent or had died, a proxy interview was conducted. The sputum samples were examined by microscopy and culture.

RESULTS

The overall relapse rate was 7.0% in patients who were able to produce a sputum sample. Relapse appeared to be more frequent in the FDC group compared to the loose drug group (10.1% vs. 2.7%, P = 0.074).

CONCLUSION

This is the first documented long-term follow-up study of patients treated with four-drug FDCs. There is an indication that treatment of new sputum smear-positive TB patients with FDCs provides an increased risk of relapse compared to treatment with loose drugs. The long-term results of treatment with FDCs should be carefully evaluated in other settings.

Effect of Herd Characteristics, Management Practices, and Season on Different Categories of the Herd Somatic Cell Count

In this study, the contribution of management practices, herd characteristics, and seasonal variables to the herd somatic cell count (SCC) was quantified in herds with low (<150,000 cells/mL), medium (150,000-200,000 cells/mL), and high (>200,000 cells/mL) herd SCC (HSCC). Selection of the variables was performed using a linear mixed effect model; HSCC was calculated as the arithmetic mean of the individual cow's SCC. The data concerning management practices were derived from 3 questionnaires on mastitis prevention and management practices on 246 Dutch dairy farms. The monthly Dairy Herd Improvement test data of these 246 farms were used to calculate the herd characteristics and seasonal effects. None of the management practices were associated with HSCC in all 3 HSCC categories. Some variables only had a significant association with HSCC in one HSCC category, such as dry premilking treatment (-9,100 cells/mL in the low HSCC category) or feeding calves with high SCC milk (11,100 cells/ mL in the medium HSCC category). Others had an opposite effect on HSCC in different HSCC categories, such as average parity (-6,400 and 11,000 cells/mL in the low and medium HSCC category, respectively) and feeding calves with fresh milk (10,300 and -9,700 cells/ mL in the low and high HSCC category, respectively). We conclude that, given the individual Dairy Herd Improvement data and information on management practices of an individual farm, it is possible to provide quantitative insight into the contribution of these different variables to the HSCC of an individual farm. Being able to provide such insight is a prerequisite for interpretation, prediction, and control of HSCC on individual dairy farms.

Relation between stallion sperm binding to homologous hemizonae and fertility

The hemizona assay (HZA) has been developed as a diagnostic test to predict the fertilisation potential of human spermatozoa. The aim of this study was to develop an HZA for stallion spermatozoa and to investigate a possible relationship between fertility and the outcome of the HZA in this species. Equine oocytes were obtained from ovaries collected at a slaughterhouse and by transvaginal, ultrasound-guided follicle aspiration. They were then denuded from cumulus cells and stored in salt solution at 4 degrees C until use. On the day of the experiments the oocytes were bisected, thus providing 2 equal matching hemizonae from each oocyte. Semen samples from Dutch Warmblood stallions with known fertility data were used to assess the number of spermatozoa bound to the outer side of the hemizona after incubation in vitro. Sperm binding to matching hemizonae of a particular stallion was similar and confirmed the feasibility of using the HZA for the horse. Sperm hemizona binding capacity of 10 pairs of stallions was compared by incubating 1 hemizona with the semen of a stallion and the matching hemizona with the semen of another stallion from the same stud farm. Five matching pairs of hemizonae were used for each pair of stallions. There was a significant relationship between the mean number of spermatozoa bound to matching hemizonae and the fertility indices of stallions from each stud farm (P < 0.0001). It is concluded that HZA can be used as a valuable parameter in stallion semen analysis.

The assessment of biomarkers in sentinel cattle for monitoring vanadium exposure

Various potential biomarkers were sampled for vanadium every 3-4 months from Bos indicus beef cattle farmed extensively immediately adjacent (high exposure (HE) group) and two km away (low exposure (LE) group) from a vanadium processing plant, respectively. Vanadium intake (mg vanadium kg(-1) bwt d(-1)) was modelled using environmental and physiological data as inputs. The vanadium intake ranged from 0.57 to 5.44 mg vanadium kg(-1) bwt d(-1) in the HE group and 0.41 to 2.61 mg vanadium kg(-1) bwt d(-1) in the LE group over a five-year period of monitoring. Samples collected from live sentinel animals over the five-year period included caudal coccygeal vertebrae, tail-switch hair, milk, urine, faeces, rib-bone biopsies and a wide range of blood clinical pathology and haematological parameters. The data was analysed for differences in response between the HE and LE groups. Where differences were found, a linear mixed-effects regression model was fitted to model the relationship between the exposure dose and the response variable. The model included the effects of age, duration of exposure and response, and allowed the prediction of the exposure dose given these inputs. Moreover, forty-two adult cattle were slaughtered over the five years. A wide range of tissue samples, rumen content and whole blood were taken from the cattle at slaughter for vanadium determination. In live animals, a difference in response was found between the HE group and LE group with respect to serum albumin (n = 36), monocyte (n = 36) and thrombocyte (n = 36) counts, and hair (n = 2) and faeces (n = 34) vanadium concentrations. No difference in vanadium concentrations could be shown for urine (n = 36), the traditional occupational health biomarker. Regression models are described for serum albumin, monocyte counts, faeces and hair, which showed the most promise as biomarkers. Average concentrations of vanadium in the tissues of slaughtered cattle ranged from 0.08 to 2.94 mg kg(-1) (wet-weight basis) and rumen content contained 16.67 mg kg(-1). Significant correlations were found between the exposure dose (end-dose) just prior to slaughter and the concentrations of vanadium in the coccygeal vertebrae, liver, diaphragm and rib-bone in descending order of magnitude. Other tissues showed poor correlation to the end-dose. Tissue levels of vanadium in healthy cattle include a much wider range than is currently reflected in the literature. The best tissue from slaughter animals for assessing chronic vanadium exposure is probably the liver.

Quantifying transmission of Campylobacter spp. among broilers

Campylobacter species are frequently identified as a cause of human gastroenteritis, often from eating or mishandling contaminated poultry products. Quantitative knowledge of transmission of Campylobacter in broiler flocks is necessary, as this may help to determine the moment of introduction of Campylobacter in broiler flocks more precisely. The aim of this study was to determine the transmission rate parameter in broiler flocks. Four experiments were performed, each with four Campylobacter-inoculated chicks housed with 396 contact chicks per group. Colonization was monitored by regularly testing fecal samples for Campylobacter. A mathematical model was used to quantify the transmission rate, which was determined to be 1.04 new cases per colonized chick per day. This would imply that, for example, in a flock of 20,000 broilers, the prevalence of Campylobacter would increase from 5% to 95% within 6 days after Campylobacter introduction. The model and the estimated transmission rate parameter can be used to develop a suitable sampling scheme to determine transmission in commercial broiler flocks, to estimate whether control measures can reduce the transmission rate, or to estimate when Campylobacter was introduced into a colonized broiler flock on the basis of the time course of transmission in the flock.

Comparative histological studies of mechanically versus manually processed sheep intestines used to make natural sausage casings

The natural sausage casings industry is large and worldwide, and casings prepared from the small intestine of sheep form a large part of it. Food safety authorities in several countries have been concerned about the risk to consumers from the bovine spongiform encephalopathy (BSE) agent. Although this agent could enter the European small ruminant population via infected feed, there is no evidence that it has. Because the BSE agent introduced experimentally into sheep and goats has a tissue distribution very similar to that found in animals with natural cases of scrapie, the agent would likely be found in the intestine and lymph nodes of some infected sheep from an early age. When natural casings are prepared from the intestine, the ileum (known to be infected in animals with natural cases of scrapie) is removed and the intestine is cleaned such that the inner (tunica mucosa) and outer (tunica serosa and tunica muscularis) layers are removed, leaving only the submucosa. There are two main methods for cleaning the intestine: manual and mechanical. The cleaning efficiency of these two methods was examined in the commercial environment as practiced on healthy sheep considered fit for human consumption in Turkey and Great Britain. The investigation involved a qualitative and quantitative histological approach. There was no significant difference in cleaning efficiency between the two methods, although there was some variation. No Peyer's patches or residues of them were found in any part of the cleaned casings. This finding is important because in sheep infected with transmissible spongiform encephalopathies (TSEs) Peyer's patches are likely to contain a major part of the intestinal infectivity. No serosa was found in any casing, but some residual mucosa and muscularis was retained, with more of the former than the latter. The results indicate that the cleaning efficiency of the two methods was broadly equivalent, that there was significant removal of tissue that could promote TSE infection, and that TSE risk reduction likely would be achieved by both methods, although this probability could not be quantified by the methods used in this study.

In vitro growth of mastitis-inducing Escherichia coli in milk and milk fractions of dairy cows

The outcome of E. coli mastitis in cows ranges from mild to severe in individual animals. This study explored the hypothesis that milk from individual cows differs in its growth medium properties for E. coli, and whether possible variation could be related to specific milk constituents. To mimic the early phase of intramammary E. coli infection, a low inoculum size and a short incubation period were used. Cell-reduced, cell- and fat-free (skim) and cell- and fat-free and protein-reduced (whey) fractions were prepared from whole milk samples (n=18). Ten ml of whole milk, milk fractions and brain heart infusion broth (BHI) were inoculated with approximately 100cfu E. coli. After 6h of incubation, bacterial counts were assessed by dilution plating in triplicate. Bacterial counts in whole milk differed up to a 100-fold between cows, which was not associated with SCC. Bacterial counts were significantly higher in whey fractions than in whole milk, cell-reduced and skim fractions and variation in whey was smaller, indicating that the acid-precipitable protein fraction contains the milk constituents of major relevance for inhibition of and variation in bacterial growth. The presence of fat and cells added to bacterial growth inhibition to a lesser extent. In conclusion, in vitro growth of E. coli in milk differs substantially between individual cows within an incubation period comparable with the early phase of intramammary infection. This suggests that the growth medium properties of milk could be of importance in the pathogenesis of E. coli mastitis and subsequent outcome of disease.

Intestinal calcium absorption in growing dogs is influenced by calcium intake and age but not by growth rate

The effects of calcium (Ca) intake (V(I)), age and growth rate on intestinal Ca absorption were studied in growing dogs. Two breeds of dogs differing in their growth rate (67 Great Danes and 23 Miniature Poodles) were raised on diets differing only in their Ca content (range 0.33 to 3.3 g/100 g diet on a dry matter basis). Repetitive Ca balance studies were performed with the aid of (45)Ca from 6 wk (i.e., after weaning) until 6 mo of age. Several models were investigated expressing true Ca absorption (V(a)) as a function of V(I), breed and age. V(a) was directly proportional to a function close to V(I)(0.82) being a continuation of the high Ca needs for mineralization of the growing skeleton. This curvilinear relationship between V(a) and V(I) and the inverse relationship between fractional Ca absorption and V(I) indicated the presence of active and passive Ca absorption in weaned growing dogs. A model in which these two components of Ca absorption can be discerned revealed that active Ca absorption underwent age-dependent changes, whereas passive absorption remained constant and accounted for 53% absorption of the V(I). At low V(I), active absorption contributed to a significant part of the V(a), whereas at excessive V(I) active absorption was negligible and passive absorption was the driving force for causing supra positive Ca balance. Intestinal Ca handling did not differ between breeds with dramatically different mature body size and growth rates.

Diversity and seasonal fluctuations of the dominant members of the bacterial soil community in a wheat field as determined by cultivation and molecular methods

There is a paucity of knowledge on microbial community diversity and naturally occurring seasonal variations in agricultural soil. For this purpose the soil microbial community of a wheat field on an experimental farm in The Netherlands was studied by using both cultivation-based and molecule-based methods. Samples were taken in the different seasons over a 1-year period. Fatty acid-based typing of bacterial isolates obtained via plating revealed a diverse community of mainly gram-positive bacteria, and only a few isolates appeared to belong to the Proteobacteria and green sulfur bacteria. Some genera, such as Micrococcus, Arthrobacter, and Corynebacterium were detected throughout the year, while Bacillus was found only in July. Isolate diversity was lowest in July, and the most abundant species, Arthrobacter oxydans, and members of the genus Pseudomonas were found in reduced numbers in July. Analysis by molecular techniques showed that diversity of cloned 16S ribosomal DNA (rDNA) sequences was greater than the diversity among cultured isolates. Moreover, based on analysis of 16S rDNA sequences, there was a more even distribution among five main divisions, Acidobacterium, Proteobacteria, Nitrospira, cyanobacteria, and green sulfur bacteria. No clones were found belonging to the gram-positive bacteria, which dominated the cultured isolates. Seasonal fluctuations were assessed by denaturing gradient gel electrophoresis. Statistical analysis of the banding patterns revealed significant differences between samples taken in different seasons. Cluster analysis of the patterns revealed that the bacterial community in July clearly differed from those in the other months. Although the molecule- and cultivation-based methods allowed the detection of different parts of the bacterial community, results from both methods indicated that the community present in July showed the largest difference from the communities of the other months. Efforts were made to use the sequence data for providing insight into more general ecological relationships. Based on the distribution of 16S rDNA sequences among the bacterial divisions found in this work and in literature, it is suggested that the ratio between the number of Proteobacteria and Acidobacterium organisms might be indicative of the trophic level of the soil.

Relationships of age and shape of the navicular bone to the development of navicular disease: a radiological study

Estimating the shape of the proximal articular border of the navicular bone and grading the radiological navicular bone condition (grades 3 and 4 representing the most severe changes), the aim of this study was to assess potential age-related implications of the previously reported shape predisposition to navicular disease in 746 normal and 174 clinically affected Dutch Warmbloods age 3-19 years. A significant, age-independent, shape-grade association found in normal and affected horses emphasises the fundamental character of the shape predisposition to navicular disease. A significant age-related increase of the least susceptible shape prevalence was found in elderly normal horses. A shape-independent low grades 3 and 4 prevalence (mean 15%) was found in normal horses, vs. a high grades 3 and 4 prevalence (mean 85%) in the affected horses. Therefore, the clinical manifestation of the disease is grade-rather than shape-dependent. A significant age-related appearance of inverted flask-shaped channels and enthesophytes was found in the clinically affected horses. However, considering the significant shape-radiological features association previously reported in 3-year-old normal horses, this association may be shape- rather than age-dependent.

Complementation of a gl-deficient feline herpesvirus recombinant by allotopic expression of truncated gl derivatives

The alphaherpesvirus glycoproteins gE and gI form a hetero-oligomeric complex involved in cell-to-cell transmission. The gI-deficient recombinant feline herpesvirus (FHV), FHVdeltagI-LZ, produces plaques that are only 15% the size of those of wild-type FHV. Here, we have complemented FHV(delta)gI-LZ allotopically by expressing intact gI and C-terminally truncated gI derivatives from the thymidine kinase locus. The effect on gE-gI-mediated cell-to-cell spread was assessed by plaque assay employing computer-assisted image analysis (software available at http://www.androclus.vet.uu.nl/spotter/spotter.htm+ ++). Allotopic complementation with intact gI fully restored plaque size. Deletion of the C-terminal 11 residues of gI did not affect cell-to-cell spread, whereas deletion of the complete cytoplasmic tail reduced plaque size by only 35%. Mutants expressing gI166, roughly corresponding to the N-terminal half of the ectodomain, displayed a small-plaque phenotype. Nevertheless, their plaques were reproducibly larger than those of matched gI-deficient controls, indicating that the gE-gI166 hetero-oligomer, though crippled, is still able to mediate cell-to-cell spread. Our data demonstrate that plaque analysis provides a reliable and convenient tool to measure and quantitate gE-gI function in vitro.

Impact of human immunodeficiency virus infection on the outcome of treatment and survival of tuberculosis patients in Mwanza, Tanzania

SETTING

Little is known about the outcome of tuberculosis (TB) treatment and subsequent survival of human immunodeficiency virus (HIV) infected patients treated under routine programme conditions in a developing country. We followed a cohort of HIV-positive and HIV-negative tuberculosis patients during therapy and assessed their vital and tuberculosis status 3 years after completion of treatment in Mwanza, Tanzania.

METHODS

Newly diagnosed and relapse tuberculosis cases consecutively registered over a 6-month period were enrolled into an epidemiological study of TB/HIV. Treatment outcome was based on information in tuberculosis treatment registers. Patients surviving treatment were assessed 3 years later by personal interview. Cause of death was determined by verbal autopsy.

RESULTS

Of 561 patients enrolled into the study, 505 patients alive at completion of treatment were eligible for assessment at 3 years. Except for mortality, HIV infection was not statistically associated with differing treatment outcomes. At time of follow-up, the overall mortality was 19% and was associated with HIV infection (hazard ratio [hr] 3.7, 95% confidence interval [CI] 2.6-5.2) and age 35 years and over (hr 1.5, 95% CI 1.02-2.1), but not with type of tuberculosis, gender, or initial drug resistance. By life table analysis, probability of survival at 4 years was 35% for HIV-positive patients compared to 90% for HIV-negative patients. Although no relapse cases were diagnosed, verbal autopsy suggested equivalent low rates of relapse in both groups.

CONCLUSION

These results demonstrate the effectiveness of the current approach to the treatment of tuberculosis patients regardless of HIV status. However, HIV-related mortality remains high both during and following completion of treatment, and further studies are needed to determine if this mortality might be reduced by simple interventions which are feasible in developing countries.

Flow cytometric measurement of neutrophil alkaline phosphatase before and during initiation of an induced Escherichia coli mastitis in cattle

In 12 healthy cows, neutrophil alkaline phosphatase (NAP) activity was measured by flow cytometer before and during an experimentally induced Escherichia coli mastitis, to study the role and increase of NAP in Gram-negative bacterial infections. Percentage of neutrophils containing alkaline phosphatase and intensity of NAP activity were measured. Preinfection percentage of neutrophils with enzyme activity varied between 64.0% and 84.4% and the intensity of enzyme activity was low in all cows. After induction of infection, percentage of neutrophils with enzyme activity showed a significant decrease on day 1 followed by an significant increase on day 3. NAP intensity increased significantly on the second and third day after infection. This increase of intensity was significantly, positively correlated with the severity of infection. From this study we may conclude that variation in susceptibility to E. coli mastitis could not be explained by preinfection NAP levels. The post-infection increase of NAP activity, that was found following an induced infection was more a result of increased enzyme intensity per neutrophil, then from an increase of percentage neutrophils with enzyme activity. Furthermore, a strong correlation was found between NAP intensity and severity of inflammation. There was evidence that the more severely diseased animals showed stronger NAP intensity increase.

Evaluation of a sustained 7-year health education campaign on leprosy in Rufiji District, Tanzania

To assess the impact of a 7-year intensive health education campaign about leprosy delivered by workers of the Kindwitwi Leprosy Trust to schoolchildren and general public in Rufiji District. Knowledge, attitude and beliefs towards leprosy were measured in Rufiji and compared to neighbouring Kisarawe District as control. Lessons learned from this analysis may be useful for the planning and evaluating of health education campaigns. Interview of schoolchildren, general public, community leaders, traditional healers and medical staff in both districts. A stratified randomized sampling scheme was used, with stratification for urban and rural settings. A representative sample of schoolchildren, general public, community leaders, traditional healers and medical staff in Rufiji District and in the control area of Kisarawe District was interviewed. The interviews were partly structured and partly open. The results of the interviews were analysed in the context of epidemiological leprosy data from 1985 till 1995, and demographic data of both districts. Data entry and statistical analysis was done using FileMaker Pro, Stata and Excel computer packages. We did not observe positive effects of the health education campaign on the indicators regarding early diagnosis of leprosy with less disability. Leprosy case detection was declining in both districts. We found that the campaign had a favourable impact on the knowledge and the attitude of schoolchildren in Rufiji District. We could demonstrate a relationship between increased knowledge of leprosy and a positive, less stigmatizing attitude. Knowledge of leprosy was better in Rufiji as compared to Kisarawe, but only among schoolchildren. We found indications that low level of education, rural residence, older age, female gender and Moslem religion were associated with stigmatizing attitudes and beliefs towards leprosy. Knowledge about leprosy reactions among medical staff interviewed was not optimal. The exact outcome of the sustained campaign in Rufiji District was difficult to assess because no comparison could be made with the situation prior to the campaign. However, the health education campaign was associated with increased knowledge and diminished tendency to stigmatize leprosy among schoolchildren. Health education campaigns have to be sustained and have to cover a broad sector of the society in order to induce behavioural changes in the community. The focus of health education should be rural communities and schools, and pay special attention to women, religious leaders and traditional healers. Awareness of diagnosis and treatment of leprosy reactions among medical staff should be improved.

Relationship between sperm-zona pellucida binding assays and the 56-day nonreturn rate of cattle inseminated with frozen-thawed bull semen

Assays based on sperm-zona pellucida binding have been developed as diagnostic tests to predict the fertilizing potential of mammalian spermatozoa. Recently, we reported on the development of a sperm-zona pellucida binding assay (SZBA) for bull spermatozoa. The aim of the present study was to develop a hemi-zona assay (HZA) for bull spermatozoa and to investigate the relationship between SZBA and HZA outcomes and in vivo fertility. Frozenthawed semen samples from 8 fertile Swedish Red and White bulls (one ejaculate per bull) designated as the test semen samples and a single ejaculate from a fertile Holstein-Friesian bull designated as the control semen sample were used in this study. In the SZBA, 2 groups of 20 oocytes per semen test sample and in the HZA a minimum of 6 matching pairs of hemizonae were used for comparison of sperm binding with control semen. Sperm binding to matching hemi-zonae of individual semen samples was equal, and clearly demonstrated the feasibility of the HZA for cattle. A significant correlation was found between the SZBA and the HZA indices obtained from the different semen test samples (r = 0.42, P < 0.001; n = 67). There was no significant relation between the SZBA indices and the 56-d nonreturn rate of the test samples. However, the HZA indices of the semen test samples and the 56-d nonreturn rate were significantly correlated (r = 0.46, P < 0.0001; n = 67). It is concluded that HZA can be regarded as a potential assay for predicting the fertilizing ability of bovine semen samples. However, further studies using more semen samples are necessary to confirm this view.

Association between leprosy and HIV infection in Tanzania

SETTING

An epidemiological study of the interaction of leprosy and HIV infection in Tanzania.

OBJECTIVE

To establish the prevalence of HIV infection among leprosy patients, and to measure the association of HIV and leprosy by comparing the HIV prevalence in leprosy patients and blood donors.

DESIGN

Testing for HIV infection in consecutively diagnosed leprosy patients (new and relapsed after MDT) in all regions in Tanzania successively for a period of 3 to 6 months during 1991, 1992 and 1993.

RESULTS

Out of the total estimated eligible leprosy patients, 697 patients (69%) entered the final analysis. The HIV prevalence among these leprosy patients was 12% (83/697) as compared to 6% (8960/ 158,971) in blood donors examined in Tanzania during the same period. There were no significant differences in HIV seroprevalence by age, sex, residence or type of disease. However, the adjusted odds ratio (OR) of the presence of a BCG scar was 1.9 [95% confidence interval (CI) 1.1-3.3] among HIV-positive leprosy cases compared to HIV-negative leprosy cases. Comparing leprosy cases with blood donors as controls, the logistic regression model, controlling for sex, age group and residence, showed the OR for HIV seropositivity among leprosy patients to be 2.5 (95% CI 2.0-3.2). This association existed in all strata, but was strongest in the 15-34-year age group. No difference of HIV status between multibacillary and paucibacillary leprosy could be shown to exist. The point estimate of the population attributable risk of HIV infection for leprosy was 7%.

CONCLUSION

HIV infection is associated with leprosy and might reverse the epidemiological trend of the slow decline in case notification in Tanzania if HIV infection is increasing greatly. Previous BCG vaccination loses its protection against leprosy in the presence of HIV infection. A repeated study is recommended in order to validate these findings, whereby recording of the disability grading of the cases is necessary to adjust for delay in diagnosis.

Within day and between day variation of the in vitro under agarose chemotaxis assay in bovine

The present study was conducted to determine within day variation (experiment I) and between day variation (experiment II) of the in vitro under agarose chemotaxis assay. Further, results from experiment II were used to estimate a more stable immunological parameter for the chemotactic activity. In experiment I, blood samples of eight cows were taken every 4 h starting at 0800 during a 24 h period. This procedure was replicated on three different days with peripheral white blood cells of lactating bovine. Chemotactic differential showed variation within a day. The differences between samplings were not constant over the days, but varied randomly from day to day. In experiment II, 12 cows were followed for 8 consecutive days and blood samples for chemotaxis assay were taken once a day at 0730. Differences between the days were significant. With a conditional auto regression model of the first order adjusted least squares means of each cow were estimated over the 8 consecutive days. The chemotactic value of a day was used to estimate the value of the next day. Expanding the model with more previous days did not improve the model. The results of this study indicate that blood samples for chemotaxis should be taken at the same time of the day to control for within day variation. If a sequence of chemotactic values is available we strongly suggest working with adjusted least square means of chemotactic differentials. These adjusted means show less random variation and are a more stable parameter for chemotactic activity.

Risk of recurrence of repeat breeding in sows with a repeat breeding in the first parity

Risk of recurrence of repeat breeding in sows with a repeat breeding in the 1st parity was investigated in 241 sow herds (1985-1990). The association between repeat breeding in the 1st and subsequent parities was examined using data on 9,120 sows. Each sow contributed only one pair of observations to the total data set. Occurrence of repeat breeding in the 1st and higher parities was presented in terms of recurrent risk rates (rRR), adjusted for different strata of herds. Sows with a repeat breeding in the 1st parity did not have a significantly higher risk rate for recurrence of a repeat breeding in the 2nd parity (rRR = 1.12, 95% confidence interval .97-1.29) and in the 3rd parity (rRR = 1.10, 95% confidence interval .86-1.41) compared to sows without a repeat breeding in the 1st parity. Sows with a repeat breeding in the 1st parity had a slightly higher risk rate for recurrence of a repeat breeding in the 4th or higher parity (rRR = 1.07, 95% confidence interval 1.03-1.10), compared to sows without a repeat breeding in the 1st parity. However, this risk is, in a biological sense, very small.

Role of navicular bone shape in the pathogenesis of navicular disease: a radiological study

From progeny lists of 30 Dutch Warmblood sires, 586 3-year-old females by these stallions were randomly selected, each progeny group aimed at 20 animals for statistical reasons. The front feet of the sires and female progeny were examined radiographically using lateromedial and dorsopalmar upright pedal projections. The radiological features associated with navicular disease were classified 0-4 using a standardised classification, grades 3 and 4 representing the more severe changes. The shape of the proximal articular border of the navicular bone outline on the dorsopalmar view was classified 1-4; 1=concave; 2=undulating; 3=straight; 4=convex. A significant shape-grade association was found, the highest grades 3 and 4 incidence demonstrated by shape 4. In shapes 1 and 2, navicular bones grades 3 and 4 features were mainly characterised by inverted flask-shaped channels. In shape 3, navicular bones grades 3 and 4 were dominated by enthesiophytes. These findings indicate an apparent shape predisposition to radiological changes associated with navicular disease. The shape of the navicular bone in the offspring was on average the same as the sire, indicating an hereditary element in navicular bone shape.

A score test for zero inflation in a Poisson distribution

When analyzing Poisson-count data sometimes a lot of zeros are observed. When there are too many zeros a zero-inflated Poisson distribution can be used. A score test is presented to test whether the number of zeros is too large for a Poisson distribution to fit the data well.

Evaluation of optimal age at first conception in gilts from data collected in commercial swine herds

The purpose of this study was to find the economically optimal period of first conception in gilts, addressing the issues of lifetime reproductive performance and expected herd life. A profit equation was used to combine the effects into one economic parameter. The data were from 14,910 gilts on 54 farms throughout The Netherlands. The average number of pigs born alive in the first litter increased with older age at conception. In the second litter a similar, but much smaller, effect was observed. Age at first conception had no effect on number of pigs born alive in the third or greater litter. Gilts bred at an older age had a shorter expected herd life than gilts bred at a younger age. Evaluating the reasons for culling revealed that infertility became a more important reason with increasing age at first conception. The proportion culled for infertility increased linearly from 18% at conception on d 200 to 24.5% at conception on d 300. Combining the effect of litter size and herd life led to the conclusion that the profit per gilt (sow) was not significantly affected by her age at first conception. It is concluded that the optimal economic age at first conception was considered to be approximately 200 to 220 d of age when the cost of housing and feed of the gilt from entry to first conception were taken into account.

HIV-1 infection as a risk factor for leprosy; a case-control study in Tanzania

A case-control study was carried out in Tanzania to determine the relative risk of those with HIV-1 infection for getting leprosy. Cases were 93 consecutively diagnosed patients with leprosy aged 15-54 years from the Mwanza Region. Controls were a representative population sample of 4161 people drawn from a stratified cluster sample from urban areas, roadside settlements, and rural villages. HIV-1 infection was determined by enzyme-linked immunosorbent assay (ELISA); Western blot was used when the ELISA result was indeterminate. The HIV-1 prevalence in leprosy cases was 10% in rural (7 of 72) and in roadside and urban areas (2 of 21); in controls these prevalences were 3.4% and 9.9%, respectively. The relative risk of HIV-1 infection for the development of leprosy was estimated to be 2.2 [95% confidence interval (CI) = 1.0-4.7; p = 0.07]. HIV-1 infection was significantly associated with multibacillary (MB) leprosy (odds ratio 4.6; CI = 1.3-13.2) but not with paucibacillary leprosy (odds ratio 1.4; 95% CI = 0.4-3.8). The population etiological fraction for the development of MB leprosy attributable to HIV-1 infection in this population is estimated to be 13% (95% CI = 4%-23%). We conclude that HIV-1 is a risk factor for the development of MB leprosy. The impact of the HIV-1 epidemic on the incidence of leprosy so far has been limited since HIV-1 occurs mainly in urban areas and leprosy in rural areas.

Development of a sperm zona pellucida binding assay for bull semen

Assays based on sperm zona pellucida binding have been developed as diagnostic tests to predict the fertilisation potential of human spermatozoa. The aim of this study was to establish a similar assay for bull sperm. The results showed differences between established fertile bulls in the relative numbers of sperm cells bound to the zona pellucida of a batch of oocytes. These differences suggest that there may be a relationship between the sperm zona pellucida binding capacity and the fertility of bulls.

Bacteriuria in men infected with HIV-1 is related to their immune status (CD4+ cell count)

OBJECTIVE

Reports from the United States that urinary tract infections (UTI) are more common in homosexual than in heterosexual men have not been confirmed in Europe. The occurrence of several UTI in men infected with HIV-1 has been recorded in The Netherlands. We therefore analysed the relationship between the presence of bacteriuria and the immune status (CD4+ cell count) in these HIV-1-infected patients.

DESIGN

Urinary cultures were obtained prospectively for 2 years, during the first visit and every 6 months thereafter, when signs and symptoms of UTI occurred and when patients had fever of unknown origin. CD4+ cell counts were measured at the same time.

SETTING

The study was performed at the University Hospital, Utrecht, The Netherlands.

PATIENTS, PARTICIPANTS

One hundred and thirty HIV-1-infected men attended our hospital. Data from 98 were analysed. Eighty-nine (91%) of these men were either homo- or bisexual.

MAIN OUTCOME MEASURES

Positive urinary culture.

RESULTS

Group 1 (CD4+ cell count less than 200 x 10(6)/l) consisted of 47 patients; 30% had at least one period of bacteriuria, with 21 episodes. Group 2 (CD4+ cell count 200-500 x 10(6)/l) consisted of 27 patients; 11% had at least one period of bacteriuria, with five episodes. We did not find bacteriuria in the 24 patients in group 3 (CD4+ cell count greater than 500 x 10(6)/l). The rate of bacteriuria per patient-month, 4 (group 1) versus 2 (group 2), differed significantly (P less than 0.001). A significant relationship between CD4+ cell count and bacteriuria was found (P = 0.00003); no relationship, however, was found with anal intercourse, hospitalization, Karnofsky score, follow-up, or age.

CONCLUSION

We conclude that men infected with HIV and presenting with a CD4+ cell count less than 200 x 10(6)/l are at increased risk for bacteriuria.

Changes in pulsatile secretion patterns of LH, FSH, progesterone, androstenedione and oestradiol in cows after superovulation with PMSG

Six heifers were injected i.m. with 2500 i.u. PMSG followed by 15 mg prostaglandin 48 h later. Serial blood samples were collected through a catheter in the caudal vena cava every 10 min for 8 h on Day 10 (7 h after PMSG administration), during luteal regression (7 h after prostaglandin administration) and on the day thereafter. Four normally cyclic heifers served as a control group. Concentrations of progesterone, androstenedione, oestradiol, LH, FSH, and PMSG in the vena cava samples were measured and the frequency and amplitudes of episodic pulses of all hormones were estimated except for PMSG. Ovaries were collected by ovariectomy at 50 h after onset of luteal regression to determine the number of preovulatory follicles (non-atretic follicles greater than or equal to 10 mm). Stimulation of follicular growth by administration of PMSG resulted in the following effects on the secretion of steroids and endogenous gonadotrophins. (1) There were no alterations in progesterone concentration and the amplitude and frequency of episodic pulses. Mean (+/- s.e.m.) concentrations were 54.1 +/- 5.8, 19.1 +/- 3.1 and 3.4 +/- 0.9 nmol/l on Day 10 (L), during luteal regression (LR) and on the day thereafter (F) respectively. (2) There were no alterations in the episodic secretion patterns of androstenedione. Mean concentrations were 0.20 +/- 0.02, 0.15 +/- 0.02 and 0.11 +/- 0.02 nmol/l for the L, LR and F periods respectively. (3) There was an increase in oestradiol concentration from 17.1 +/- 3.0 pmol/l during the L period to 233.7 +/- 86.4 pmol/l during the F period. Pulse amplitude was enhanced compared to corresponding periods in control animals whereas pulse frequency remained the same. The oestradiol concentration was significantly correlated with the number of preovulatory follicles (r = 0.82, P less than 0.05). (4) There was a suppression of the frequency of episodic LH pulses (/8 h) during the LR (3.2 +/- 0.7) and F (4.3 +/- 0.4) periods compared to corresponding periods in control heifers (9.5 +/- 0.9 and 7.0 +/- 1.5 respectively). The preovulatory LH peak occurred earlier in 4 of 6 treated heifers. (5) There was a suppression of FSH concentrations, pulse amplitude and frequency during the LR and F (17.4 +/- 0.9 mg/l, 4.7 +/- 0.8 microgram/l and 7.5 +/- 0.4 pulses/8 h) periods compared to the corresponding F-period values (35.6 +/- 6.2 mg/l, 9.8 +/- 1.6 micrograms/l and 9.3 +/- 0.3 pulses/8 h) in control heifers.(ABSTRACT TRUNCATED AT 400 WORDS)

Efficacy of 15-(123I)-p-iodophenyl pentadecanoic acid (IPPA) in assessing myocardial metabolism in a model of reversible global ischemia

In a canine model of reversible global ischemia, the residual quantity of 123I was assessed following a bolus injection of 15-p-(123I)-iodophenyl pentadecanoic acid (123I-IPPA). This technique was used to assess changes in free fatty acid metabolism following the utilization of three cardioplegic formulations. Cardioplegic arrest was initiated with Tyers' iso-osmolar (IO) solution (Group A); IO + superoxide dismutase (SOD) (Group B) and IO + allopurinol (Group C). Pre and post operative scanning were completed with 2-5 mCi 123I-IPPA. Clearance was assessed by IPPA time activity curve analysis generating t1/2 (half lives in min) for the early and late phases of the curve. The assessment between groups demonstrated that the elimination of 123I-IPPA products (early phase) was faster from the lateral wall in groups B and C versus group A (14 +/- 12 min, 13 +/- 9 min and 24 +/- 10 min, respectively). The elimination of IPPA (late phase) was also faster from the lateral wall in groups B and C when compared to group A (240 +/- 270 min, 132 +/- 85 min and 416 +/- 238 min). Examining the changes between control and postoperative values for each area of the left ventricle within each group demonstrated no significant changes for groups B and C. Group A, however, demonstrated significantly increased t1/2 values for the lateral wall (early and late phases) and the apical wall (late phase).(ABSTRACT TRUNCATED AT 250 WORDS)