A method for assessing teatcup liner performance during the peak milk flow period.

The objective of this study was to develop a method to quantify the milking conditions under which circulatory impairment of teat tissues occurs during the peak flow period of milking. A secondary objective was to quantify the effect of the same milking conditions on milk flow rate during the peak flow rate period of milking. Additionally, the observed milk flow rate was a necessary input to the calculation of canal area, our quantitative measure of circulatory impairment. A central composite experimental design was used with 5 levels of each of 2 explanatory variables (system vacuum and pulsator ratio), creating 9 treatments including the center point. Ten liners, representing a wide range of liner compression (as indicated by overpressure), were assessed, with treatments applied using a novel quarter-milking device. Eight cows (32 cow-quarters) were used across 10 separate evening milkings, with quarter being the experimental unit. The 9 treatments, with the exception of a repeated center point, were randomly applied to all quarters within each individual milking. Analysis was confined to the peak milk flow period. Milk flow rate (MFR) and teat canal cross sectional area (CA) were normalized by dividing individual MFR, or CA, values by their within-quarter average value across all treatments. A multiple explanatory variable regression model was developed for normalized MFR and normalized CA. The methods presented in this paper provided sufficient precision to estimate the effects of vacuum (both at teat-end and in the liner mouthpiece), pulsation, and liner compression on CA, as an indicator of teat-end congestion, during the peak flow period of milking. Liner compression (as indicated by overpressure), teat-end vacuum, vacuum in the liner mouthpiece, milk-phase time, and their interactions are all important predictors of MFR and teat-end congestion during the peak milk flow period of milking. Increasing teat-end vacuum and milk-phase time increases MFR and reduces CA (indicative of increased teat-end congestion). Increasing vacuum in the liner mouthpiece also acts to reduce CA and MFR. Increasing liner compression reduces the effects of teat-end congestion, resulting in increased MFR and increased CA at high levels of teat-end vacuum and milk-phase time. These results provide a better understanding of the balance between milking speed and milking gentleness.

Estimating teat canal cross-sectional area to determine the effects of teat-end and mouthpiece chamber vacuum on teat congestion.

The primary objective of this experiment was to assess the effect of mouthpiece chamber vacuum on teat-end congestion. The secondary objective was to assess the interactive effects of mouthpiece chamber vacuum with teat-end vacuum and pulsation setting on teat-end congestion. The influence of system vacuum, pulsation settings, mouthpiece chamber vacuum, and teat-end vacuum on teat-end congestion were tested in a 2×2 factorial design. The low-risk conditions for teat-end congestion (TEL) were 40 kPa system vacuum (Vs) and 400-ms pulsation b-phase. The high-risk conditions for teat-end congestion (TEH) were 49 kPa Vs and 700-ms b-phase. The low-risk condition for teat-barrel congestion (TBL) was created by venting the liner mouthpiece chamber to atmosphere. In the high-risk condition for teat-barrel congestion (TBH) the mouthpiece chamber was connected to short milk tube vacuum. Eight cows (32 quarters) were used in the experiment conducted during 0400 h milkings. All cows received all treatments over the entire experimental period. Teatcups were removed after 150 s for all treatments to standardize the exposure period. Calculated teat canal cross-sectional area (CA) was used to assess congestion of teat tissue. The main effect of the teat-end treatment was a reduction in CA of 9.9% between TEL and TEH conditions, for both levels of teat-barrel congestion risk. The main effect of the teat-barrel treatment was remarkably similar, with a decrease of 9.7% in CA between TBL and TBH conditions for both levels of teat-end congestion risk. No interaction between treatments was detected, hence the main effects are additive. The most aggressive of the 4 treatment combinations (TEH plus TBH) had a CA estimate 20% smaller than for the most gentle treatment combination (TEL plus TBL). The conditions designed to impair circulation in the teat barrel also had a deleterious effect on circulation at the teat end. This experiment highlights the importance of elevated mouthpiece chamber vacuum on teat-end congestion and resultant decreases in CA.

Assessing liner performance using on-farm milk meters.

The primary objective of this study was to quantify and compare the interactive effects of liner compression, milking vacuum level, and pulsation settings on average milk flow rates for liners representing the range of liner compression of commercial liners. A secondary objective was to evaluate a methodology for assessing liner performance that can be applied on commercial dairy farms. Eight different liner types were assessed using 9 different combinations of milking system vacuum and pulsation settings applied to a herd of 80 cows with vacuum and pulsation conditions changed daily for 36d using a central composite experimental design. Liner response surfaces were created for explanatory variables milking system vacuum (Vsystem) and pulsator ratio (PR) and response variable average milk flow rate (AMF=total yield/total cups-on time) expressed as a fraction of the within-cow average flow rate for all treatments (average milk flow rate fraction, AMFf). Response surfaces were also created for between-liner comparisons for standardized conditions of claw vacuum and milk ratio (fraction of pulsation cycle during which milk is flowing). The highest AMFf was observed at the highest levels of Vsystem, PR, and overpressure. All liners showed an increase in AMF as milking conditions were changed from low to high standardized conditions of claw vacuum and milk ratio. Differences in AMF between liners were smallest at the most gentle milking conditions (low Vsystem and low milk ratio), and these between-liner differences in AMF increased as liner overpressure increased. Differences were noted with vacuum drop between Vsystem and claw vacuum depending on the liner venting system, with short milk tube vented liners having the greater vacuum drop than mouthpiece chamber vented liners. The accuracy of liner performance assessment in commercial parlors fitted with milk meters can be improved by using a central composite experimental design with a repeated center point treatment, rotating different clusters to different stalls (milk meters), and adjusting performance estimates for similar claw vacuum and pulsation conditions.

Effect of pulsation rest phase duration on teat end congestion.

The objective of this study was to quantify the effect of d-phase (rest phase) duration of pulsation on the teat canal cross-sectional area during the period of peak milk flow from bovine teats. A secondary objective was to test if the effect of d-phase duration on teat canal cross-sectional area was influenced by milking system vacuum level, milking phase (b-phase) duration, and liner overpressure. During the d-phase of the pulsation cycle, liner compression facilitates venous flow and removal of fluids accumulated in teat-end tissues. It was hypothesized that a short-duration d-phase would result in congestion of teat-end tissue and a corresponding reduction in the cross-sectional area of the teat canal. A quarter milking device, designed and built at the Milking Research and Instruction Laboratory at the University of Wisconsin-Madison, was used to implement an experiment to test this hypothesis. Pulsator rate and ratios were adjusted to achieve 7 levels of d-phase duration: 50, 100, 150, 175, 200, 250, and 300ms. These 7 d-phase durations were applied during one milking session and were repeated for 2 vacuum levels (40 and 50kPa), 2 milking phase durations (575 and 775ms), and 2 levels of liner overpressure (9.8 and 18kPa). We observed a significant reduction in the estimated cross-sectional area of the teat canal with d-phase durations of 50 and 100ms when compared with d-phase durations of 150, 175, 225, 250, and 300ms. No significant difference was found in the estimated cross-sectional area of the teat canal for d-phase durations from 150 to 300ms. No significant interaction was observed between the effect of d-phase and b-phase durations, vacuum level, or liner overpressure.

Methods of estimating liner compression.

The aim of this study was to compare 2 methods of measuring overpressure (OP) using a new test device designed to make OP measurements more quickly and accurately. Overpressure was measured with no pulsation (OP np) and with limited pulsation (OP lp) repeatedly on the same cow during a single milking. Each of the 6 liners (3 round liners and 3 triangular liners) used in this study were tested on the same 6 experimental cows. Both OP np and OP lp were measured on all 4 teats of each experimental cow twice for each liner. The order of OP np and OP lp alternated sequentially for each cow test. The OP results for the 6 liners were also compared with liner compression estimated on the same liners with a novel artificial teat sensor (ATS). The OP lp method showed small but significantly higher values than the OP np method (13.9 vs. 13.4 kPa). The OP lp method is recommended as the preferred method as it more closely approximates normal milking condition. Overpressure values decreased significantly between the first and the following measurements, (from 15.0 to 12.4 kPa). We recommend performing the OP test at a consistent time, 1 min after attaching the teatcup to a well-stimulated teat, to reduce the variability produced by OP changing during the peak flow period. The new test device had several advantages over previously published methods of measuring OP. A high correlation between OP and liner compression estimated by the ATS was found, but difficulties were noted when using the ATS with triangular liners.

Isolated myocardial bridging and exercise-related cardiac events.

Myocardial bridging, which is defined as cardiac muscle overlying a part of a coronary artery, is the most common congenital coronary artery anomaly. Myocardial bridging is usually benign, but has been associated with exercise-related cardiac events. Guidelines for athletic participation in these patients are primarily based on reports from the general population with myocardial bridging. We performed a systematic literature search of PubMed, Ovid and Google Scholar for articles addressing exercise-related cardiac events associated with myocardial bridging. We identified 69 cases of which only 35 were well defined. We conclude that there are insufficient data to form definitive guidelines as to how physically active individuals with myocardial bridging should be managed. Prudence suggests that management should be individualized for those with possible symptoms. Beta adrenergic blockade is recommended as initial medical therapy. Surgery should be restricted to those with continued symptoms despite beta blocker therapy. There is no evidence that asymptomatic individuals without clinical evidence of ischemia should be restricted from vigorous activity.

The UHRF1 protein is a key regulator of retrotransposable elements and innate immune response to viral RNA in human cells.

While epigenetic mechanisms such as DNA methylation and histone modification are known to be important for gene suppression, relatively little is still understood about the interplay between these systems. The UHRF1 protein can interact with both DNA methylation and repressive chromatin marks, but its primary function in humans has been unclear. To determine what that was, we first established stable UHRF1 knockdowns (KD) in normal, immortalized human fibroblasts using targeting shRNA, since CRISPR knockouts (KO) were lethal. Although these showed a loss of DNA methylation across the whole genome, transcriptional changes were dominated by the activation of genes involved in innate immune signalling, consistent with the presence of viral RNA from retrotransposable elements (REs). We confirmed using mechanistic approaches that 1) REs were demethylated and transcriptionally activated; 2) this was accompanied by activation of interferons and interferon-stimulated genes and 3) the pathway was conserved across other adult cell types. Restoring UHRF1 in either transient or stable KD systems could abrogate RE reactivation and the interferon response. Notably, UHRF1 itself could also re-impose RE suppression independent of DNA methylation, but not if the protein contained point mutations affecting histone 3 with trimethylated lysine 9 (H3K9me3) binding. Our results therefore show for the first time that UHRF1 can act as a key regulator of retrotransposon silencing independent of DNA methylation.

Adiposity attenuates muscle quality and the adaptive response to resistance exercise in non-obese, healthy adults.

BACKGROUND: Emerging data have revealed a negative association between adiposity and muscle quality (MQ). There is a lack of research to examine this interaction among young, healthy individuals, and to evaluate the contribution of adiposity to adaptation after resistance exercise (RE). OBJECTIVE: The purpose of this investigation was to examine the influence of subcutaneous adipose tissue (SAT) on muscle function among non-obese individuals before and after RE. DESIGN: Analyses included 634 non-obese (body mass index <30 kg m(-2)) subjects (253 males, 381 females; age=23.3 ± 5.2 years). SAT and muscle mass (magnetic resonance imaging-derived SAT and biceps muscle volume), isometric and dynamic biceps strength, and MQ (strength/muscle volume), were analyzed at baseline and after 12 weeks of unilateral RE. RESULTS: At baseline, SAT was independently associated with lower MQ for males (ß=-0.55; P<0.01) and females (ß=-0.45; P<0.01), controlling for body mass and age. Adaptation to RE revealed a significant negative association between SAT and changes for strength capacity (ß=-0.13; p=0.03) and MQ (ß=-0.14; P<0.01) among males. No attenuation was identified among females. Post-intervention SAT remained a negative predictor of MQ for males and females (ß=-0.47; P<0.01). CONCLUSIONS: The findings reveal that SAT is a negative predictor of MQ among non-obese, healthy adults, and that after 12 weeks of progressive RE this association was not ameliorated. Data suggest that SAT exerts a weak, negative influence on the adaptive response to strength and MQ among males.

The definition of exertion-related cardiac events.

Vigorous physical activity increases the risk of sudden cardiac death (SCD) and acute myocardial infarction (AMI) but there is no standard definition as to what constitutes an exertion-related cardiac event, specifically the time interval between physical exertion and cardiac event. A systematic review of studies related to exertion-related cardiac events was performed and the time interval between exertion and the event or the symptoms leading to the event was looked for in all the articles selected for inclusion. A total of 12 of 26 articles "suggested" or "defined" exertion-related events as those events whose symptoms started during or within 1 h of exertion. Others used definitions of 0.5 h, 2 h, "during exertion", "during or immediately post exertion" and "during or within several hours after exertion". It is suggested, therefore, that the definition of an exertion-related cardiac event be established as a cardiac event in which symptoms started during or within 1 h of physical exertion.

Atrial fibrillation in endurance-trained athletes.

BACKGROUND: Endurance exercise training produces multiple cardiac adaptations including changes in electrophysiological function that may make endurance-trained athletes more vulnerable to atrial fibrillation (AF). This possible association is not recognised by many practising cardiologists and sports physicians. Consequently, we performed a literature review to examine the relationship between atrial fibrillation and endurance exercise training among athletes. PubMed was searched from January 1960 through December 2008 to identify articles examining the relationship between endurance exercise training and AF. RESULTS: Evidence suggests that athletes are at increased risk for development of AF. Possible factors increasing AF in this population include increased parasympathetic tone, reduced sympathetic tone, increased atrial size and increased inflammation. DISCUSSION: Suggested management of AF in athletes should follow similar principles to those used to manage AF in the general population.

Reversible cerebral vasoconstriction, internal carotid artery dissection and renal artery stenosis.

Reversible cerebral vasoconstriction is a rare and poorly understood syndrome, without clear diagnostic criteria. It has been described in association with multiple disorders, but has only been reported rarely in the setting of carotid artery dissection and, to our knowledge, never before in association with renal artery stenosis.

Interactions of vacuum, b-phase duration, and liner compression on milk flow rates in dairy cows.

Vacuum, b-phase duration, and liner compression are 3 milking machine factors that affect peak milk flow rate; however, extreme values of these factors can also have negative effects on teat tissue health. The main and interactive effects of vacuum, b-phase duration, and liner compression on peak milk flow rate were studied by independently controlling these causal variables over a wide range of settings, using a central composite experimental design (42 to 53 kPa of system vacuum, 220 to 800 ms of b-phase, and residual vacuum for massage of 16 to 30 kPa; corresponding to a liner compression of 8 to 14 kPa). The results of this study indicated that increasing the vacuum and b-phase duration always increased peak milk flow rate (no relative maximum was reached); however, the rate of increase of flow rate decreased as the vacuum and b-phase were increased. Increasing the liner compression also increased peak flow rates, with an increasing effect at greater vacuum. The interaction between vacuum and liner compression and the lack of interaction between b-phase and liner compression indicate that for a corresponding increase in peak milk flow rate, increasing the b-phase produced less teat-end tissue congestion than increasing the vacuum. The effect of milking vacuum on peak milk flow rate was smaller than that reported in previous studies, probably because of the independent adjustment of milking vacuum and liner compression used in this study. The effect of b-phase duration on peak milk flow was also smaller in this study than in previous studies, probably because of the independent adjustment of b-phase and d-phase durations used in this study.

Chorea, transverse myelitis, neuropathy and a distinctive MRI: paraneoplastic manifestations of probable small cell lung cancer.

Paraneoplastic chorea occurs most commonly in association with small cell lung cancer, often in combination with other paraneoplastic phenomena and sometimes with distinctive basal ganglia T2-weighted MRI hyperintensities. A case of acute-onset chorea is presented in which this phenomenon, combined with transverse myelitis, neuropathy and the described characteristic MRI changes prompted positron emission tomography scanning, in which evidence of probable small cell cancer was uncovered.

Acute convexity subarachnoid haemorrhage: a cause of aura-like symptoms in the elderly.

Late-life onset aura-like symptoms are not rare and can be potentially misdiagnosed as transient ischaemic attacks. The cause is often obscure. Four cases of recurrent aura-like symptoms are presented in whom acute convexity subarachnoid haemorrhage (SAH) contralateral to symptoms was demonstrated. Three experienced subsequent events or groups of events triggered by recurrent SAH. Negative diffusion-weighted imaging, normal electroencephalography and slow symptom march with complete resolution argued against ischaemic and epileptic causes. Aura-like symptoms in the elderly should be investigated with imaging modalities most sensitive for detecting subarachnoid blood, in particular gradient echo magnetic resonance imaging.

Resolution of dopamine dysregulation syndrome following cessation of dopamine agonist therapy in Parkinson's disease.

Repetitive and compulsive behaviours can occur in association with the use of dopaminergic medications for the treatment of Parkinson's disease (PD). This syndrome has been referred to as the 'dopamine dysregulation syndrome'. The prognosis for patients with this syndrome is unclear. We report five PD patients in whom the abnormal behaviours resolved completely after withdrawal of dopamine agonist therapy. We alert clinicians to the apparent role of dopamine agonists in this syndrome. In addition, we highlight the potential reversibility of the syndrome, its varied phenomenology and its potential pathophysiology.

Leptin responses to long-term cardiorespiratory exercise training without concomitant weight loss: a prospective study.

AIM: The aims of the present study were to examine 1) whether changes in circulating leptin levels occur in response to six months of aerobic exercise training (ET) without concomitant weight loss; 2) whether there is a different response with respect to gender; and 3) the relationship between age and leptin and whether this relationship has any impact on the response to ET without weight-loss. METHODS: Thirty-eight healthy, sedentary men and women (age 38.43+/-2.24, range 18-59 years) participated in 6 months of supervised, moderate intensity (ET) performed 4 days per week. Maintenance of usual dietary practices were encouraged to minimize weight-loss. Participants were evaluated for circulating fasting leptin, body mass, body fat percentage and maximal aerobic power (VO2max) prior to and after ET. RESULTS: There was no decrease in body weight or leptin concentration (17.69+/-2.67 vs 16.85+/-3.12 ng dL(-1)). Gender did not affect the response to exercise training. The bivariate correlation between leptin and age was not significant, but the relationship reached significance after controlling for body fat percentage and VO2max (r = -0.358, P < 0.05). Age did not affect the response of leptin concentration to ET. CONCLUSION: It is probable that changes in leptin concentration reported previously with ET may be attributable to concomitant weight loss, but age does not play a role in how leptin responds to ET.

GTF2IRD1 regulates transcription by binding an evolutionarily conserved DNA motif 'GUCE'.

GTF2IRD1 is a member of a family of transcription factors whose defining characteristic is varying numbers of a helix-loop-helix like motif, the I-repeat. Here, we present functional analysis of human GTF2IRD1 in regulation of three genes (HOXC8, GOOSECOID and TROPONIN I(SLOW)). We define a regulatory motif (GUCE-GTF2IRD1 Upstream Control Element) common to all three genes. GUCE is bound in vitro by domain I-4 of GTF2IRD1 and mediates transcriptional regulation by GTF2IRD1 in vivo. Definition of this site will assist in identification of other downstream targets of GTF2IRD1 and elucidation of its role in the human developmental disorder Williams-Beuren syndrome.

A genome-wide association study identifies risk loci for childhood acute lymphoblastic leukemia at 10q26.13 and 12q23.1.

Genome-wide association studies (GWASs) have shown that common genetic variation contributes to the heritable risk of childhood acute lymphoblastic leukemia (ALL). To identify new susceptibility loci for the largest subtype of ALL, B-cell precursor ALL (BCP-ALL), we conducted a meta-analysis of two GWASs with imputation using 1000 Genomes and UK10K Project data as reference (totaling 1658 cases and 7224 controls). After genotyping an additional 2525 cases and 3575 controls, we identify new susceptibility loci for BCP-ALL mapping to 10q26.13 (rs35837782, LHPP, P=1.38 × 10-11) and 12q23.1 (rs4762284, ELK3, P=8.41 × 10-9). We also provide confirmatory evidence for the existence of independent risk loci at 9p21.3, but show that the association marked by rs77728904 can be accounted for by linkage disequilibrium with the rare high-impact CDKN2A p.Ala148Thr variant rs3731249. Our data provide further insights into genetic susceptibility to ALL and its biology.

Reasons for admission to hospital for Parkinson's disease.

The management of Parkinson's disease (PD) tends to focus on the presenting motor syndrome; yet, in the long term, nonmotor complications of the illness and complications of treatment become increasingly troublesome. The aims of this study were to review the reasons for 761 hospital admissions for patients with a diagnosis of PD and to determine the cause of hospitalization. Only 15% were admitted for primary management of the motor syndrome. PD was the secondary diagnosis in 645 admissions. Of the latter, 39% were admitted because of falls leading to fracture, pneumonia, encephalopathy or dementia and hypotension with syncope. Cardiac and gastrointestinal diseases accounted for a further 22% of admissions. Complications of the later stages of PD and associated treatments are more likely to lead to hospital admission than management of the primary motor syndrome. Some of the emergency hospital admissions for PD may be potentially avoidable with better planning of management in the outpatient and community setting.

Paranodal pathology in Tangier disease with remitting-relapsing multifocal neuropathy.

Pathological studies of a sural nerve biopsy in a man with Tangier disease presenting as a remitting-relapsing multifocal neuropathy showed abnormalities in the paranodal regions, including lipid deposition (65%) and redundant myelin foldings, with various degrees of myelin splitting and vesiculation (43%) forming small tomacula and abnormal myelin terminal loops (4%). The internodal regions were normal in the majority of myelinated fibres. Abnormal lipid storage was also present in the Schwann cells of the majority of unmyelinated fibres (67%). The evidence suggests that the noncompacted myelin region of the paranode is a preferential site for lipid storage in the myelinated Schwann cell, and that the space-occupying effects of the cholesterol esters leads to paranodal malfunction and tomacula formation as the pathological basis for the multifocal relapsing-remitting clinical course.