Device-measured sedentary behaviour and anxiety symptoms during adolescence: a 6-year prospective cohort study

BACKGROUND

Sedentary behaviour is potentially a modifiable risk factor for anxiety disorders, a major source of global disability that typically starts during adolescence. This is the first prospective study of associations between repeated, device-based measures of sedentary behaviour and anxiety symptoms in adolescents.

METHODS

A UK cohort with 4257 adolescents aged 12 at baseline (56% female). Main exposures were sedentary behaviour and physical activity measured using accelerometers for 7-days at ages 12, 14, and 16. Primary outcome was anxiety symptom scores at age 18 from a Clinical Interview Schedule-Revised. We used adjusted negative binomial regression and iso-temporal substitution methods to analyse the data.

RESULTS

We found a positive association between sedentary behaviour at ages 12, 14, and 16, with anxiety symptoms at age 18, independent of total physical activity volume. Theoretically replacing an hour of daily sedentary behaviour for light activity at ages 12, 14, and 16, was associated with lower anxiety symptoms by age 18 by 15.9% (95% CI 8.7-22.4), 12.1% (95% CI 3.4-20.1), and 14.7% (95% CI 4-24.2), respectively. Whereas, theoretically replacing an hour of sedentary behaviour with moderate-to-vigorous physical activity was not associated with differences in anxiety symptoms. These results were robust to a series of sensitivity analyses.

CONCLUSION

Sedentary behaviour is a possible risk factor for increasing anxiety symptoms during adolescence, independent of total physical activity volume. Instead of focusing on moderate-to-vigorous activity, replacing daily sedentary behaviour with light activity during adolescence could be a more suitable method of reducing future anxiety symptoms.

Cambridge hybrid closed-loop algorithm in children and adolescents with type 1 diabetes: a multicentre 6-month randomised controlled trial

BACKGROUND

Closed-loop insulin delivery systems have the potential to address suboptimal glucose control in children and adolescents with type 1 diabetes. We compared safety and efficacy of the Cambridge hybrid closed-loop algorithm with usual care over 6 months in this population.

METHODS

In a multicentre, multinational, parallel randomised controlled trial, participants aged 6-18 years using insulin pump therapy were recruited at seven UK and five US paediatric diabetes centres. Key inclusion criteria were diagnosis of type 1 diabetes for at least 12 months, insulin pump therapy for at least 3 months, and screening HbA1c levels between 53 and 86 mmol/mol (7·0-10·0%). Using block randomisation and central randomisation software, we randomly assigned participants to either closed-loop insulin delivery (closed-loop group) or to usual care with insulin pump therapy (control group) for 6 months. Randomisation was stratified at each centre by local baseline HbA1c. The Cambridge closed-loop algorithm running on a smartphone was used with either (1) a modified Medtronic 640G pump, Medtronic Guardian 3 sensor, and Medtronic prototype phone enclosure (FlorenceM configuration), or (2) a Sooil Dana RS pump and Dexcom G6 sensor (CamAPS FX configuration). The primary endpoint was change in HbA1c at 6 months combining data from both configurations. The primary analysis was done in all randomised patients (intention to treat). Trial registration ClinicalTrials.gov, NCT02925299.

FINDINGS

Of 147 people initially screened, 133 participants (mean age 13·0 years [SD 2·8]; 57% female, 43% male) were randomly assigned to either the closed-loop group (n=65) or the control group (n=68). Mean baseline HbA1c was 8·2% (SD 0·7) in the closed-loop group and 8·3% (0·7) in the control group. At 6 months, HbA1c was lower in the closed-loop group than in the control group (between-group difference -3·5 mmol/mol (95% CI -6·5 to -0·5 [-0·32 percentage points, -0·59 to -0·04]; p=0·023). Closed-loop usage was low with FlorenceM due to failing phone enclosures (median 40% [IQR 26-53]), but consistently high with CamAPS FX (93% [88-96]), impacting efficacy. A total of 155 adverse events occurred after randomisation (67 in the closed-loop group, 88 in the control group), including seven severe hypoglycaemia events (four in the closed-loop group, three in the control group), two diabetic ketoacidosis events (both in the closed-loop group), and two non-treatment-related serious adverse events. There were 23 reportable hyperglycaemia events (11 in the closed-loop group, 12 in the control group), which did not meet criteria for diabetic ketoacidosis.

INTERPRETATION

The Cambridge hybrid closed-loop algorithm had an acceptable safety profile, and improved glycaemic control in children and adolescents with type 1 diabetes. To ensure optimal efficacy of the closed-loop system, usage needs to be consistently high, as demonstrated with CamAPS FX.

FUNDING

National Institute of Diabetes and Digestive and Kidney Diseases.

Impact of replacing sedentary behaviour with other movement behaviours on depression and anxiety symptoms: a prospective cohort study in the UK Biobank

BACKGROUND

Sedentary behaviour is potentially a modifiable risk factor for depression and anxiety disorders, but findings have been inconsistent. To assess the associations of sedentary behaviour with depression and anxiety symptoms and estimate the impact of replacing daily time spent in sedentary behaviours with sleep, light, or moderate to vigorous physical activity, using compositional data analysis methods.

METHODS

We conducted a prospective cohort study in 60,235 UK Biobank participants (mean age: 56; 56% female). Exposure was baseline daily movement behaviours (accelerometer-assessed sedentary behaviour and physical activity, and self-reported total sleep). Outcomes were depression and anxiety symptoms (Patient Health Questionnaire-9 and Generalised Anxiety Disorders-7) at follow-up.

RESULTS

Replacing 60 min of sedentary behaviour with light activity, moderate-to-vigorous activity, and sleep was associated with lower depression symptom scores by 1.3% (95% CI, 0.4-2.1%), 12.5% (95% CI, 11.4-13.5%), and 7.6% (95% CI, 6.9-8.4%), and lower odds of possible depression by 0.95 (95% CI, 0.94-0.96), 0.75 (95% CI, 0.74-0.76), and 0.90 (95% CI, 0.90-0.91) at follow-up. Replacing 60 min of sedentary behaviour with moderate-to-vigorous activity and sleep was associated with lower anxiety symptom scores by 6.6% (95% CI, 5.5-7.6%) and 4.5% (95% CI, 3.7-5.2%), and lower odds of meeting the threshold for a possible anxiety disorder by 0.90 (95% CI, 0.89-0.90) and 0.97 (95%CI, 0.96-0.97) at follow-up. However, replacing 60 min of sedentary behaviour with light activity was associated with higher anxiety symptom scores by 4.5% (95% CI, 3.7-5.3%) and higher odds of a possible anxiety disorder by 1.07 (95% CI, 1.06-1.08).

CONCLUSIONS

Sedentary behaviour is a risk factor for increased depression and anxiety symptoms in adults. Replacing sedentary behaviour with moderate-to-vigorous activity may reduce mental health risks, but more work is necessary to clarify the role of light activity.

The association between cardiorespiratory fitness and the incidence of common mental health disorders: A systematic review and meta-analysis

BACKGROUND

Physical activity is associated with a lower incidence of common mental health disorder, but less is known about the impact of cardiorespiratory fitness (CRF).

METHODS

In this review, we systematically evaluated the relationship between CRF and the incidence of common mental health disorders in prospective cohort studies. We systematically searched six major electronic databases from inception to 23rd of May 2019. We assessed study quality using the Newcastle-Ottawa scale.

RESULTS

We were able to pool the hazard ratios (HRs) and 95% confidence intervals (CIs) of four studies including at least 27,733,154 person-years of data. We found that low CRF (HR = 1.47, [95% CI 1.23 - 1.76] p < 0.001 I2 = 85.1) and medium CRF (HR = 1.23, [95% CI 1.09 - 1.38] p < 0.001 I2 = 87.20) CRF are associated with a 47% and 23% greater risk of a common mental health disorders respectively, compared with high CRF. We found evidence to suggest a dose-response relationship between CRF and the risk of common mental health disorders.

LIMITATIONS

We were only able to identify a small number of eligible studies from our search and heterogeneity was substantial in the subsequent meta-analysis.

CONCLUSIONS

Our findings indicate that there is a longitudinal association between CRF levels and the risk of a common mental health disorder. CRF levels could be useful for identifying and preventing common mental health disorders at a population-level.

A systematic review and meta-analysis of clinical predictors of lithium response in bipolar disorder

OBJECTIVE

To determine clinical predictors of lithium response in bipolar disorder.

METHODS

Systematic review of studies examining clinical predictors of lithium response was conducted. Meta-analyses were performed when ≥2 studies examined the same potential predictor.

RESULTS

A total of 71 studies, including over 12 000 patients, identified six predictors of good response: mania-depression-interval sequence [odds ratio (OR): 4.27; 95% CI: 2.61, 6.97; P < 0.001], absence of rapid cycling (OR for rapid cycling: 0.30; 95% CI: 0.17, 0.53; P < 0.001), absence of psychotic symptoms (OR for psychotic symptoms: 0.52; 95% CI: 0.34, 0.79; P = 0.002), family history of bipolar disorder (OR: 1.61; 95% CI: 1.03, 2.52; P = 0.036), shorter prelithium illness duration [standardised mean difference (SMD): -0.26; 95% CI: -0.41, -0.12; P < 0.001] and later age of onset (SMD: 0.17; 95% CI: 0.02, 0.36; P = 0.029). Additionally, higher body mass index was associated with poor response in two studies (SMD: -0.61; 95% CI: -0.90, -0.32; P < 0.001). There was weak evidence for number of episodes prior to lithium treatment (SMD: -0.42; 95% CI: -0.84, -0.01; P = 0.046), number of hospitalisations before lithium (SMD: -0.40; 95% CI: -0.81, 0.01; P = 0.055) and family history of lithium response (OR: 10.28; 95% CI: 0.66, 161.26; P = 0.097).

CONCLUSIONS

The relative importance of these clinical characteristics should be interpreted with caution because of potential biases and confounding.

Curiosity killed the cat: no evidence of an association between cat ownership and psychotic symptoms at ages 13 and 18 years in a UK general population cohort

BACKGROUND

Congenital or early life infection with Toxoplasma gondii has been implicated in schizophrenia aetiology. Childhood cat ownership has been hypothesized as an intermediary marker of T. gondii infection and, by proxy, as a risk factor for later psychosis. Evidence supporting this hypothesis is, however, limited.

METHOD

We used birth cohort data from the Avon Longitudinal Study of Parents and Children (ALSPAC) to investigate whether cat ownership in pregnancy and childhood (ages 4 and 10 years) was associated with psychotic experiences (PEs) in early (age 13, N = 6705) and late (age 18, N = 4676) adolescence, rated from semi-structured interviews. We used logistic regression to examine associations between cat ownership and PEs, adjusting for several sociodemographic and socioeconomic factors, household characteristics and dog ownership. Missing data were handled via multiple imputation.

RESULTS

Cat ownership during pregnancy was not associated with PEs at age 13 years [adjusted odds ratio (OR) 1.15, 95% confidence interval (CI) 0.97-1.35] or 18 years (OR 1.08, 95% CI 0.86-1.35). Initial univariable evidence that cat ownership at ages 4 and 10 years was associated with PEs at age 13 years did not persist after multivariable adjustment (4 years: OR 1.18, 95% CI 0.94-1.48; 10 years: OR 1.12, 95% CI 0.92-1.36). There was no evidence that childhood cat ownership was associated with PEs at age 18 years.

CONCLUSIONS

While pregnant women should continue to avoid handling soiled cat litter, given possible T. gondii exposure, our study strongly indicates that cat ownership in pregnancy or early childhood does not confer an increased risk of later adolescent PEs.

Childhood interleukin-6, C-reactive protein and atopic disorders as risk factors for hypomanic symptoms in young adulthood: a longitudinal birth cohort study

BACKGROUND

There are no existing longitudinal studies of inflammatory markers and atopic disorders in childhood and risk of hypomanic symptoms in adulthood. This study examined if childhood: (1) serum interleukin-6 (IL-6) and C-reactive protein (CRP); and (2) asthma and/or eczema are associated with features of hypomania in young adulthood.

METHOD

Participants in the Avon Longitudinal Study of Parents and Children, a prospective general population UK birth cohort, had non-fasting blood samples for IL-6 and CRP measurement at the age of 9 years (n = 4645), and parents answered a question about doctor-diagnosed atopic illness before the age of 10 years (n = 7809). These participants completed the Hypomania Checklist at age 22 years (n = 3361).

RESULTS

After adjusting for age, sex, ethnicity, socio-economic status, past psychological and behavioural problems, body mass index and maternal postnatal depression, participants in the top third of IL-6 values at 9 years, compared with the bottom third, had an increased risk of hypomanic symptoms by age 22 years [adjusted odds ratio 1.77, 95% confidence interval (CI) 1.10-2.85, p < 0.001]. Higher IL-6 levels in childhood were associated with adult hypomania features in a dose-response fashion. After further adjustment for depression at the age of 18 years this association remained (adjusted odds ratio 1.70, 95% CI 1.03-2.81, p = 0.038). There was no evidence of an association of hypomanic symptoms with CRP levels, asthma or eczema in childhood.

CONCLUSIONS

Higher levels of systemic inflammatory marker IL-6 in childhood were associated with hypomanic symptoms in young adulthood, suggesting that inflammation may play a role in the pathophysiology of mania. Inflammatory pathways may be suitable targets for the prevention and intervention for bipolar disorder.

The effect of sibutramine prescribing in routine clinical practice on cardiovascular outcomes: a cohort study in the United Kingdom

BACKGROUND/OBJECTIVES

The marketing authorization for the weight loss drug sibutramine was suspended in 2010 following a major trial that showed increased rates of non-fatal myocardial infarction and cerebrovascular events in patients with pre-existing cardiovascular disease. In routine clinical practice, sibutramine was already contraindicated in patients with cardiovascular disease and so the relevance of these influential clinical trial findings to the 'real World' population of patients receiving or eligible for the drug is questionable. We assessed rates of myocardial infarction and cerebrovascular events in a cohort of patients prescribed sibutramine or orlistat in the United Kingdom.

SUBJECTS/METHODS

A cohort of patients prescribed weight loss medication was identified within the Clinical Practice Research Datalink. Rates of myocardial infarction or cerebrovascular event, and all-cause mortality were compared between patients prescribed sibutramine and similar patients prescribed orlistat, using both a multivariable Cox proportional hazard model, and propensity score-adjusted model. Possible effect modification by pre-existing cardiovascular disease and cardiovascular risk factors was assessed.

RESULTS

Patients prescribed sibutramine (N=23,927) appeared to have an elevated rate of myocardial infarction or cerebrovascular events compared with those taking orlistat (N=77,047; hazard ratio 1.69, 95% confidence interval 1.12-2.56). However, subgroup analysis showed the elevated rate was larger in those with pre-existing cardiovascular disease (hazard ratio 4.37, 95% confidence interval 2.21-8.64), compared with those with no cardiovascular disease (hazard ratio 1.52, 95% confidence interval 0.92-2.48, P-interaction=0.0076). All-cause mortality was not increased in those prescribed sibutramine (hazard ratio 0.67, 95% confidence interval 0.34-1.32).

CONCLUSIONS

Sibutramine was associated with increased rates of acute cardiovascular events in people with pre-existing cardiovascular disease, but there was a low absolute risk in those without. Sibutramine's marketing authorization may have, therefore, been inappropriately withdrawn for people without cardiovascular disease.

A systematic review and meta-analysis of premature mortality in bipolar affective disorder

OBJECTIVE

To review and complete meta-analysis of studies estimating standardised mortality ratios (SMRs) in bipolar affective disorder (BPAD) for all-cause and cause-specific mortalities.

METHOD

Cause-specific mortality was grouped into natural and unnatural causes. These subgroups were further divided into circulatory, respiratory, neoplastic and infectious causes, and suicide and other violent deaths. Summary SMRs were calculated using random-effects meta-analysis. Heterogeneity was examined via subgroup analysis and meta-regression.

RESULTS

Systematic searching found 31 studies meeting inclusion criteria. Summary SMR for all-cause mortality = 2.05 (95% CI 1.89-2.23), but heterogeneity was high (I(2) = 96.2%). This heterogeneity could not be accounted for by date of publication, cohort size, mid-decade of data collection, population type or geographical region. Unnatural death summary SMR = 7.42 (95% CI 6.43-8.55) and natural death = 1.64 (95% CI 1.47-1.83). Specifically, suicide SMR = 14.44 (95% CI 12.43-16.78), other violent death SMR = 3.68 (95% CI 2.77-4.90), deaths from circulatory disease = 1.73 (95% CI 1.54-1.94), respiratory disease = 2.92 (95% CI 2.00-4.23), infection = 2.25 (95% CI 1.70-3.00) and neoplasm = 1.14 (95% CI 1.10-1.21).

CONCLUSION

Despite considerable heterogeneity, all summary SMR estimates and a large majority of individual studies showed elevated mortality in BPAD compared to the general population. This was true for all causes of mortality studied.

Genetic parameters of lifetime performance traits in Holstein cows

SUMMARY

Heritabilities, genetic and phenotypic correlations among lifetime yields of milk, fat and protein, herdlife, productive life and number of lactations initiated in the herd were estimated from records of 44,933 progeny of 427 young and 119 proven Holstein sires in 1949 herds using a multivariate Reml technique to fit a sire model with relationships among young sires. Proven sires were fitted as fixed effects. Heritabilities of lifetime traits ranged from 0.005 to 0.030, suggesting little scope for direct selection for lifetime performance traits. Productive life had highest genetic correlation with lifetime fat yield (0.934), but correlations with lifetime milk and protein yields were smaller and similar (0.773 and 0.772). The number of lactations also had highest genetic correlation with lifetime fat yield. ZUSAMMENFASSUNG: Genetische Parameter von Lebensleistungsmerkmalen bei Holsteinkühen Heritabilitätswerte, genetische und phänotypische Korrelationen zwischen Lebensleistungsmerkmalen für Milch, Fett und Protein, Lebensdauer, produktive Zeit und Zahl Laktationen wurden won 44933 Nachkommen von 427 jungen und 119 nachkommenschaftsgeprüften Holsteinstieren in 1949 Herden mittels einer multivariablen REML-Technik geschätzt, die auf einem Vatertiermodell mit Verwandtschaft zwischen den jungen Stieren beruhte. Geprüfte Stiere wurden als fixe Effekte im Modell berücksichtigt. Heritabilitätswerte dieser Merkmale rangieren von 0.005 bis 0.03, so daß wenig Aussichten für Erfolg direkter Selektion auf Lebensleistungsmerkmale besteht. Die Länge des produktiven Lebens hatte die höchste genetische Korrelation mit Lebensfettmenge (0.934), aber die Korrelationen mit Milch- und Protein-Lebensleistung waren kleiner und ähnlich (0.773 und 0.772). Die Zahl der Laktationen hatte die höchste genetische Korrelation mit der Lebensfettmenge.

Short communication: Estimates of heritabilities and genetic correlations among milk fatty acid unsaturation indices in Canadian Holsteins

The objectives of the present study were to estimate genetic parameters of milk fatty acid unsaturation indices in Canadian Holsteins. Data were available on milk fatty acid composition of 2,573 Canadian Holstein cows from 46 commercial herds enrolled in the Québec Dairy Production Centre of Expertise, Valacta (Sainte-Anne-de-Bellevue, Quebec, Canada). Individual fatty acid percentages (g/100 g of total fatty acids) were determined for each milk sample by gas chromatography. The unsaturation indices were calculated as the ratio of an unsaturated fatty acid to the sum of that unsaturated fatty acid and its corresponding substrate fatty acid, multiplied by 100. A mixed linear model was fitted under REML for the statistical analysis of milk fatty acid unsaturation indices. The statistical model included the fixed effects of parity, age at calving, and stage of lactation, each nested within parity, and the random effects of herd-year-season of calving, animal, and residual. Estimates of heritabilities for the C14, C16, C18, conjugated linoleic acid, and total unsaturation indices were 0.48, 0.25, 0.29, 0.14, and 0.19, respectively. Phenotypic and genetic correlation estimates among unsaturation indices were all positive and ranged from 0.20 to 0.65 and 0.23 to 0.81, respectively. The estimates of heritabilities and genetic correlations for milk fatty acid unsaturation indices suggest that genetic variation exists among cows in milk fatty acid unsaturation, and the proportions of desirable unsaturated fatty acids from a human health point of view may be increased in bovine milk through genetic selection.

Stearoyl-CoA desaturase 1 3'UTR SNPs and their influence on milk fatty acid composition of Canadian Holstein cows

Stearoyl-CoA desaturase 1 (SCD1) catalyses the synthesis of conjugated linoleic acid (CLA) and mono-unsaturated fatty acids (MUFA) in the mammary gland of ruminant animals. Considerable variations in CLA and MUFA have been reported among animals of the same contemporary group. We hypothesized that single nucleotide polymorphisms (SNPs) in the 5' and 3' untranslated regions (UTRs) of the SCD1 gene would influence the production of SCD1 enzyme and consequently its activity in the mammary gland, which may account for some of the observed within breed variations in CLA and MUFA. The 5' and 3'UTRs of the SCD1 gene of 46 Holsteins and 35 Jerseys were analysed for SNPs by sequencing. No SNPs were identified in the 5'UTR, while 14 SNPs were identified in the 3'UTR region. Further analysis revealed three haplotype structures or regulatory variants in Holsteins: named H1, H2 and H3 and only H1 and H3 in Jerseys. An IRES motif was found in the H1 variant. A subsequent association study involving the milk fatty acid profiles of 862 Holstein cows found the H1 regulatory variant to be associated with higher C10 and C12 desaturase indices and consequently with higher contents of C10:1 and C12:1 relative to the H3 variant. The effects of the H2 variant were intermediate to those of H1 and H3. SNPs in the 3'UTR of the SCD1 gene could therefore explain some of the within-breed variations in MUFA content of milk fat.

Aziridinyl anions from a chiral, nonracemic 2-isopropylidineaziridine: surprisingly diastereoselective alkylation reactions

Lithiation and alkylation of a 2-isopropylidineaziridine bearing an (S)-alpha-methylbenzyl group on nitrogen proceeds with high levels of diastereocontrol (80-90% de).

Economic values of traits for dairy cattle improvement estimated using field-recorded data

The objective of this study was to compute economic values of traits using an empirical approach. The data set consisted of 193 257 lifetime records of Holstein and Ayrshire cows. Different profitability measurements were used as the dependent variables in covariance models to compute different sets of economic values. A kilogram genetic increase in fat production had economic values between $25 and $31 in Holstein herds and between $34 and $36 in Ayrshire herds using lifetime profit as the dependent variable. A unit genetic increase in conformation had the highest positive impact on profit ($176 in Holstein herds and $300 in Ayrshire herds) while a similar increase in capacity had a negative impact on profit (between $–30 and $–102 in Holstein herds and $–92 in Ayrshire herds). Using lifetime profit adjusted for the opportunity cost of postponed replacement reduced the influence of type traits on profit. Finally, profits of first lactations were used to study the consequences of changes in pricing systems that occurred in Quebec in August 1992. A kilogram genetic increase in protein production had negative economic values in the 1980s ($–3.70$ in Holstein herds and $–8.33 in Ayrshire herds) and positive economic values after August 1992 ($7.50 in Holstein herds and $12.83 in Ayrshire herds). Key words: Dairy cattle, economic value, field-recorded data, profitability, estimated breeding value

Asymmetric synthesis of 2-substituted piperidines using a multi-component coupling reaction: rapid assembly of (S)-coniine from (S)-1-(1-phenylethyl)-2-methyleneaziridine

(S)-Coniine is made using a reaction which assembles the piperidine ring by the sequential formation of four new chemical bonds and installs the C-2 stereogenic centre with high levels of diastereocontrol (90% de).

Reproductive responses of Holstein-Friesian cattle to the climatic conditions of central Sudan

Data were evaluated from a purebred Holstein herd (n = 1274) kept near Khartoum, a hot and dry area, from 1990 to 1996. The mixed model procedure in SAS was used to analyse the reproductive traits. The mean gestation length, days dry, number of services per conception, days from calving to first oestrus, days from calving to conception, calving interval and breeding efficiency were 279 days, 104 days, 4.2, 85.8 days, 208.9 days, 486.2 days and 74.9%, respectively. Factors that had significant effects (p < 0.01) on all the reproductive measures under study were the year and month of calving, and parity. The heritability estimates for all traits under investigation were zero. The repeatability estimates for the numbers of services per conception, days from calving to conception, days from calving to first oestrus and calving interval were 0.21 +/- 0.021, 0.12 +/- 0.024, 0.03 +/- 0.018 and 0.00, respectively. The phenotypic correlation for calving interval with numbers of service per conception was 0.05, that with days from calving to first oestrus was 0.06 and that with days from calving to conception was 0.07. Other correlations ranged from 0.00 to 0.28. The simple correlation coefficients between production and reproductive measures ranged from -0.06 to 0.45.

Genetic and environmental effects on the productivity of Holstein-Friesian cattle under the climatic conditions of central Sudan

A herd of 370 Holstein-Friesian cows were maintained in Central Sudan, Khartoum for intensive dairy production during the period 1990-1996. The area is characterized by high temperatures during the day and cools down at night, with an average thermal-humidity index (THI) of 74.8. The average adjusted lactation milk yield, milk yield per day, milk yield per day of calving interval and lactation length of the animals in the herd were 5117 +/- 123 (SE) kg, 14.7 +/- 0.25 kg, 11.3 +/- 0.36 kg and 350 +/- 8.0 days, respectively. Heifers calved at 25.2 +/- 2.3 (SD) months of age. The variation was large, which suggested large environmental fluctuations. Sire variance contributed 1.35% and 19.6% to the total variance in cows and heifers, respectively, while cow within sire contributed 19%. The heritabilities of total lactation yield, 305-day yield, milk per day of lactation, milk per day of calving interval, and lactation length in heifers were 0.78 +/- 0.24, 0.36 +/- 0.34, 0.39 +/- 0.24, 0.23 +/- 0.23, and 0.23 +/- 0.22, respectively. In cows, the heritability estimates were 0.05 +/- 0.24, 0.06 +/- 0.24, 0.08 +/- 0.24, 0.00 and 0.00 for the same traits, respectively. The repeatabilities of total lactation yield, 305-day yield, milk per day, milk per day of calving interval and lactation length were 0.02 +/- 0.03, 0.22 +/- 0.03, 0.17 +/- 0.02, 0.05 +/- 0.02 and 0.00, respectively. Regression analysis showed that, for each unit increase in THI, milk yield decreased by 0.29 +/- 0.04 kg. The stress usually caused by the combined effects of temperature and humidity was not severe in this area.

Markers within the regulatory region of the growth hormone receptor gene and their association with milk-related traits in Holsteins

We studied sequence variations in the regulatory region of the bovine growth hormone receptor gene. A polymerase chain reaction (PCR)-based method for detecting AluI, AccI, and StuI restriction fragment length polymorphisms (RFLPs) in the 5' flanking region of the bovine growth hormone receptor gene was developed and tested for association with milk-related traits in Holstein bulls. Allele frequencies of the polymorphisms in two groups of Holstein progeny-tested bulls born from 1950 to 1970 and in the 1980s, respectively, were estimated. The allele frequency of the AluI(-) allele was 0.63 and 0.42 in the bulls from 1950 to 1970 and in the 1980s, respectively. The frequency of the StuI(-) allele was 0.14 and 0.07 in the two respective bull groups. Allele frequency for AccI(-) allele was about 0.22 in both bull groups. The differences in allele frequencies for the AluI polymorphism in the two bull groups were significantly different (P < or = .005). The AluI(+/+) bulls had a higher estimated breeding value (EBV) for fat (P < or = .016) than AluI(-/-) bulls. The average effect of allele substitution for the AluI polymorphism was +/- 8 for fat EBV. The AluI polymorphism could be further evaluated for use in marker-assisted selection in dairy cattle.

Restriction fragment length polymorphisms at the ornithine decarboxylase locus associated with milk protein yield in Holsteins

Marker-assisted selection may provide the opportunity to make significant genetic gains in the improvement of economically important traits in livestock (Soller & Beckmann, 1983; Smith & Simpson, 1986). Implementation of this approach will first require identification of candidate genes or anonymous gene markers associated with the traits of interest. Candidate genes are those with a known relationship between physiological or biochemical processes and an economically important trait. In dairy cattle, genes associated with mammary gland growth, development and function are excellent candidate genes for milk production traits.

The polyamines are low molecular mass polycations that influence cell proliferation and growth (Tabor & Tabor, 1984; Pegg, 1986). Ornithine decarboxylase (ODC, EC 4.1.1.17) catalyses the conversion of ornithine to putrescine, the rate-limiting step in polyamine biosynthesis (Pegg, 1986). The level of ODC is induced in quiescent cells exposed to a wide variety of stimuli such as growth hormone, corticosteroids, testosterone and growth factors (Tabor & Tabor, 1984). There is ample evidence that growth factors influence morphogenesis and differentiation of the mammary gland (Imagawa et al. 1994). Trophic hormones that are associated with lactation, such as prolactin and growth hormone, are also required to induce differentiation of bovine mammary epithelial cells (Huynh et al. 1991; Flint & Gardner, 1994), and both mitogenic and lactogenic effects of prolactin, insulin and hydrocortisone appear to be mediated through the polyamine pathway (Rillema et al. 1977; Bedford & Zadworny, 1990; Golden & Rillema, 1993). Strange et al. (1992) have shown that ODC is involved in synthesis of a milk component; ODC has elevated expression in the lactating mammary gland, which declines sharply after weaning. It is therefore possible that particular variants of ODC could be associated with increased mammary gland function and thus influence milk related traits.

The objectives of the present study were to estimate allelic frequencies of ODC polymorphisms in Holstein bulls and to evaluate further the genotypic effects of ODC variants on milk production traits.

Bovine ornithine decarboxylase gene: cloning, structure and polymorphisms

Bovine ornithine decarboxylase (ODC) genomic clones were isolated from a bacteriophage lambda DASH genomic library. A total of 9452 bp sequence was determined which covers the entire sequence of the bovine ODC gene. Sequence analysis showed that the bovine ODC gene consisted of 12 exons which encode a protein identical to that inferred from a bovine ODC cDNA. Comparison of the structure and nucleotide sequence of the bovine, human and mouse ODC genes revealed that the gene was highly conserved. Primer extension analysis demonstrated that the transcription start point of bovine ODC mRNA was located 378 bp upstream from the A residue in the translation initiation codon. The 5'-untranslated region (UTR) of ODC mRNA was highly G + C rich, particularly in its 5'-most portion, and computer predictions suggested a very stable secondary structure for this region, with an overall free energy of formation of -134.4 kcal/mol. Conserved sequences and potential promoter elements including a TATA box, a possible CCAAT element, SP1 ranscription factor binding sites (GC boxes) and cAMP response elements (CRE) were identified in the 5'-flanking region of the gene. Two polymorphic restriction sites, a TaqI and a MspI, were mapped to the ODC gene and PCR-based methods for detection of the 2 polymorphisms were developed.

Sequence variations in the bovine growth hormone gene characterized by single-strand conformation polymorphism (SSCP) analysis and their association with milk production traits in Holsteins

Sequence variations in the bovine growth hormone (GH) gene were investigated by single strand conformation polymorphism (SSCP) analysis of seven amplified fragments covering almost the entire gene (2.7 kb). SSCPs were detected in four of these fragments and a total of six polymorphisms were found in a sample of 128 Holstein bulls. Two polymorphisms, a T-->C transition in the third intron (designated GH4.1) and an A-->C transversion in the fifth exon (designated GH6.2), were shown to be associated with milk production traits. GH4.1c/GH4.1c bulls had higher milk yield than GH4.1c/GH4.1t (P < or = 0.005) and GH4.1t/GH4.1t (P < or = 0.0022) bulls. GH4.1c/GH4.1c bulls had higher kg fat (P < or = 0.0076) and protein (P < or = 0.0018) than GH4.1c/GH4.1t bulls. Similar effects on milk production traits with the GH6.2 polymorphism were observed with the GH6.2a allele being the favorable allele. The average effects of the gene substitution for GH4.1 and GH6.2 are similar, with +/-300 kg for milk yield, +/-8 kg for fat content and +/-7 kg for protein content per lactation. The positive association of GH4.1c and GH6.2a with milk production traits may be useful for improving milk performance in dairy cattle.

A MspI polymorphism in the bovine ornithine decarboxylase gene and its possible association with selection for milk production in Holstein bulls

A polymerase chain reaction (PCR)-based method for detection of a MspI-restriction fragment length polymorphism (RFLP) in the bovine ornithine decarboxylase gene was developed, and the allele frequencies of the polymorphism in two groups of Holstein bulls representing progeny-tested bulls during the 1950s-1960s and 1980s, respectively, were estimated. The frequencies of the MspI(-) allele ere 0.229 and 0.077 and that of MspI(+) were 0.771 and 0.923 in the progeny-tested bulls of the 1950s-1960s and 1980s, respectively. The difference in allele frequencies between the two groups was statistically significant (P < 0.005). Genetic drift could be responsible for the changes in allele frequencies; however, it could also be possible that selection for milk production was associated with the changes of the allele frequencies in the two bull populations.

Molecular cloning of a bovine ornithine decarboxylase cDNA and its use in the detection of restriction fragment length polymorphisms in Holsteins

A cDNA coding for ornithine decarboxylase (ODC) was isolated from a bovine liver cDNA library. The clone (1758 base pairs) consisted of 5'- and 3'-untranslated regions of 185 and 187 nucleotides, respectively, and an open reading frame of 1383 nucleotides encoding an ODC protein (M(r) 51,342 daltons) of 461 amino acids. Comparison of the nucleotide and the predicted amino acid of the cDNA with other mammalian ODCs showed a very high degree of homology both at the DNA and protein levels. The bovine ODC mRNA was identified by northern blot to be a single species with a molecular size of 2.35 kilobase pairs. Primer extension analysis indicated that the 5'-untranslated region of the bovine ODC mRNA was 312 nucleotides long. Southern blot analysis of bovine genomic DNA revealed restriction fragment length polymorphisms when cleaved with restriction enzymes PstI, MspI, TaqI, and Bg/I.

Correlations between first lactation and lifetime performance traits of Canadian Holsteins

Data on 82,835 Holstein cows, daughters of 703 sires and with first calvings from 1979 to 1984 in 2384 herds enrolled in Quebec Dairy Herd Analysis Service, were analyzed for relationships of first lactation traits with traits for partial and total lifetime performance using multitrait REML methodology and a linear mixed model. Effects of herd-year-season, age at first calving, and proven sires were considered to be fixed, and effects of young sires and residuals were considered to be random. All known additive genetic relationships among sires were accounted for in construction of the relationship matrix. Individual lactation records were precorrected for the fixed effect of year and month of calving before lifetime totals were calculated. Each cow was given at least a 5-yr opportunity for production. All genetic and phenotypic correlations were positive except correlations of first lactation percentage traits. Correlations with partial lifetime performance were highest. Genetically, first lactation milk yield was highly correlated with most measures of lifetime performance, .64 to .92; correlations with measures of longevity were relatively smaller. Given high positive genetic correlations, selection singly on first lactation milk yield will improve all measures of lifetime performance; however, some measure of longevity should be considered in selection programs of dairy cattle.

Multitrait restricted maximum likelihood estimates of genetic and phenotypic parameters of lifetime performance traits for Canadian Holsteins

Data on 82,835 Holstein cows, daughters of 703 sires and with first calving from September 1979 to December 1984 from 2384 herds enrolled in the Quebec Dairy Herd Analysis Service, were used to estimate genetic and phenotypic parameters of partial and total lifetime performance traits with REML. The model included herd-year-season of first calving, age at first calving, and proven sires as fixed effects and young sires and residuals as random effects. Individual lactation records were precorrected for year-month of calving before lifetime totals were calculated. Only cows with at least 5 yr of opportunity for production were analyzed. The ranges of heritability estimates were .11 to .13 for lifetime production and profit, .07 to .09 for measures of longevity, and .28 to .32 for yield per day of productive life. Correlations among total lifetime yield and profit traits and among measures of longevity were > or = .93. Genetic and phenotypic correlations, respectively, of early partial (two parities total) with total life-time yield and profit and longevity traits ranged from .81 to .94 and .66 to .78. Selection on early performance seems to be desirable and, given the high positive genetic correlations, should increase both lifetime yield and longevity.

Genetic correlations between lifetime production and linearized type in Canadian Holsteins

Genetic and phenotypic correlations were estimated between 6 lifetime production and 28 linearized type traits using REML. The data set contained 34,322 cows, each with a record for all 34 traits. The analyses accounted for the fixed effects of herd, year-month, classifier, age at first calving, and stage of lactation. Heritabilities were low for lifetime traits and moderate for most type traits except stature, size, capacity, thurl width, and pin setting, which had high heritabilities. Most phenotypic correlations between lifetime production and type were in the range of .15 to .20 except for capacity, rump, and feet and legs, which were around .07. Genetic correlations were strong between lifetime production and angularity (.44 to .55) and dairy character (.53 to .56). Genetic correlations were low to moderate between life-time production and stature (.14 to .25), size (.07 to .18), texture (.19 to .26), style (.11 to .27), head (.15 to .23), pin setting (.10 to .16), rear udder (.19 to .25), and rear attachment (.10 to .22). The only notable negative genetic correlations were lifetime production with rear heel (-.16 to -.27), thurl width (-.18 to -.24), and fore udder (-.05 to -.11).

Estimates of repeatability of reproductive measures in Canadian Holsteins

Repeatabilities and heritabilities of days to first service, days open, and number of services per conception were estimated from 235,589 records on 80,333 Holstein cows, daughters of 306 sires obtained from the Quebec Dairy Herd Analysis Service, by REML. The model for statistical analyses included herd-year-season as a fixed effect and sire, cow (sire's daughter) within sire, and error as random effects. Variance components corresponding to sire, cow within sire, and error were then estimated by REML. Heritability estimates, obtained from the sire variance component, were .03, .05, and .03 for days to first service, days open, and number of services per conception, respectively. Repeatability estimates, obtained from the sire and cow within sire variance components were .08, .10, and .07 for days to first service, days open, and number of services per conception, respectively.

Identification of kappa-casein genotype in Holstein sires: a comparison between analysis of milk samples from daughters and direct analysis of semen samples from sires by polymerase chain reaction

Two different methods were used to determine kappa-casein genotypes of Holstein sires. In the earlier procedure, genotypes of sires were deduced by analyzing frequency distribution data of kappa-casein variants obtained through typing of milk samples from daughters by electrophoresis. The second method involved direct analysis of DNA obtained from semen samples of the sires. The polymerase chain reaction was used to amplify a 99-bp region from the kappa-casein gene that contains nucleotide substitutions that are diagnostic of variants A and B. Identity of the amplified product was confirmed by sequencing. Results obtained by both methods of genotyping were similar. For the 42 sires that were analyzed by both methods, the distribution of kappa-casein genotypes were 31 AA, 11 AB, and 0 BB. The frequency of B allele for kappa-casein in the sire population studied was lower than in larger Holstein cow populations. Due to the high demand for kappa-casein B milk by the dairy industry, it might be advantageous to increase this allele in the dairy cattle population by identifying sires with homozygous kappa-casein B and using them more frequently as service sires.

Genetic parameters for first milk production and composition traits for Holsteins using multivariate restricted maximum likelihood

Heritabilities and genetic and phenotypic correlations among yields of milk, fat, protein, and percentages of fat and protein were estimated from 40,984 first lactation records of daughters of 488 young and 75 proven Holstein sires using multivariate REML and a sire model accounting for relationships and sire groups. Proven sires were treated as fixed effects. Heritabilities for yields of milk, fat, protein, and percentages of fat and protein were .29, .31, .25, .65, and .61, respectively. Genetic correlations of milk with yields of fat, protein, and percentages of fat and protein and correlations of fat yield with fat percentage were .45, .79, -.49, -.54 and .56, respectively. Genetic correlations among yields and among percentage of fat and protein were the same (.62). Genetic and phenotypic correlations of protein percentage with fat and protein yields and correlations of fat percentages with protein yield were small (-.13 to .11). Phenotypic correlations were .73 to .90 among yields of milk, fat, and protein; -.31 for milk and fat percentage; -.39 for milk and protein percentage; and .38 for fat yield and fat percentage. Estimates were consistent with an earlier study utilizing data from the same population and also with other reports.

Relationships of calving ease with type traits

Type information collected by the Holstein Association of Canada was combined with calving ease data from the Quebec Dairy Herd Analysis Service. Type traits considered were overall score, general appearance, dairy character, capacity, rump, rump thurl width, rump pin setting, and set of rear legs. Calving ease was considered as a direct effect and as a maternal effect in both heifers and adult cows. After editing there were 24,618 type records, 47,023 direct effect calving ease records, and 37,068 maternal effect calving ease records from 107 sires in the analyses of heifer data. there were 26,996 type records, 16,4726 direct effect calvin ease records, and 45,261 maternal effect calving ease records in the analyses of calving involving adult cows. Multiple-trait REML was used to estimate genetic correlations between calving ease and type. The heritability of calving ease in heifers was approximately 4%, for both the direct and maternal effect, and in adult cows was approximately 1.5%. Heritability of the type traits ranged from 4 to 45%. There was a tendency for the genetic correlations between type and the direct effect of calving ease to be opposite in sign to the genetic correlations between type and the maternal effect of calving ease and for the absolute value of the correlations to be lower in adult cows than in heifers.

Correlations between udder conformation traits and somatic cell count in Canadian Holstein cows

Heritabilities of, and genetic and phenotypic correlations between, type traits and the arithmetic mean of lactational SCC were estimated using minimum norm quadratic unbiased estimation and two multitrait REML methods. Three sets of data were analyzed. Heritabilities of all traits were small. For SCC, heritabilities varied between .09 and .11 and for type traits, between .08 and .14. Genetic correlations between SCC and type traits varied between -.22 and .30. Phenotypic correlations were very low. In general, correlations indicate a rather favorable association between SCC and udder conformation traits; that is, a desirable score on type would be associated with low SCC in milk.

Estimation of repeatability of calving ease in Canadian Holsteins

Restricted maximum likelihood was used to estimate repeatabilities and heritabilities for calving ease from a data set of 636,972 Holstein parturitions obtained from the Quebec Dairy Herd Analysis Service. Subsets of the data, chosen to reflect different stages of cow maturity, were analyzed separately and compared. Initial least squares analyses were used to define the fixed effects to include in the model. The effects of herd-year-season, sex of calf, parity, and sex by parity interaction were significant in all subsets. Age and parity by age interaction were significant in subsets with primarily younger animals. Variances for sire of calf, cow, and residual effects were then estimated by REML. Repeatabilities ranged from 5.98 to 7.87% and heritabilities for calving ease as a direct effect ranged from 1.97 to 4.70%.

Relationships of milk protein types to lifetime performance

Data from 889 cows at five research stations of Agriculture Canada were used to study the effects of alpha s1-casein, beta-casein, kappa-casein, and beta-lactoglobulin loci on herdlife and total yield over fixed parities (one, two, and three parity) and to a fixed age (36, 48, and 61 mo). Actual yields of all cows were utilized to compute total milk regardless of lactational length. The model consisted of station, breed, year of birth, season of birth, and milk protein types with age at first calving as a covariate. Of the four milk protein types studied, only the kappa-casein locus had significant effects on fixed parity and fixed age total milk and herdlife. Cows with BB kappa-casein type outproduced those with AB or AA kappa-casein types in three parity total milk by 963 and 1657 kg, respectively. Considering total milk accumulated up to 61 mo of age in life, cows with BB kappa-casein type outperformed their counterparts with AB or AA kappa-casein types by 1050 and 1923 kg, respectively. Complete replacement of A by B allele at kappa-casein locus would result in an increase of 1657 kg in three parity total milk and an increase of 1923 kg in 61-mo total milk. The moderate gene frequency of kappa-casein B allele in the current dairy population can be increased to improve lifetime total milk to the benefit of the dairy industry.

Repeat parathyroid operation associated with renal disease

One hundred ten patients who had undergone operation for secondary and tertiary hyperparathyroidism have been described. Ninety patients had secondary disease and 20 patients had tertiary disease after renal transplantation. From these two groups, 18 patients had repeat operations for control of recurrent or persistent disease. The incidence of repeat operations was 14 percent. Causes were graft-dependent hyperparathyroidism, supernumerary glands in the neck or mediastinum, and incomplete identification of glands in the neck. The most important risk factor is continued long-term dialysis in functionally anephric patients. We recommend that patients with hyperparathyroidism associated with chronic renal failure undergo total parathyroidectomy with autotransplantation. If repeat operation is necessary, a reduction in glandular mass with autotransplantation is preferred. In selected patients, total parathyroidectomy can be considered because of the increased risk of aluminum bone disease.

Long-term patency of polytetrafluoroethylene graft fistulas

Polytetrafluoroethylene grafts have been the mainstay for hemoaccess at our dialysis unit since 1976. Of 528 grafts placed in the forearm, 81 were evaluated for long-term patency and complication rates. When appropriate diagnostic studies and clinical signs delineate the cause of graft problems, a variety of surgical techniques can be used to maintain graft patency. The overall patency rate was 81 percent at 4.47 years. There were 3.5 complications per graft and 1 procedure per 1.25 years of follow-up. Over two thirds of the grafts had minimal complications and showed a 95 percent patency rate at 4.76 years. Impra grafts seemed to fare better than Gore-tex grafts, but their patency and duration were similar. Polytetrafluoroethylene grafts are easy to use, easy to revise and repair, have a long shelf life, and can withstand repeated dialysis access for many years.

Correlations between production traits in first lactation Holstein cows

Genetic and phenotypic correlations between milk yield, fat (yield and percent, protein (yield and percent), and somatic cell count in first lactation Holstein cows were estimated using a multivariate restricted maximum likelihood algorithm. There were 18,189 daughters of 257 sires in 928 herds. Genetic correlations between pairs of yield traits were all positive (.73 to .88), but phenotypic correlations with somatic cell count were small and negative. Genetic correlations between somatic cell count, and fat percent, and protein percent were negative, -.11. Milk yield, fat yield, and protein yield had heritabilities of .36, .38, and .25.

Variation in milk protein concentrations associated with genetic polymorphism and environmental factors

Concentrations of alpha s-casein, beta-casein, kappa-casein, beta-lactoglobulin, alpha-lactalbumin, serum albumin, and immunoglobulin in milk from 1888 Holstein cows were determined monthly over the lactation period. Cows were phenotyped for genetic variants of alpha s1-casein, beta-casein, kappa-casein, and beta-lactoglobulin. Least squares analyses showed variations in individual proteins due to parity number, month of test, stage of lactation, somatic cell count, fat content, milk yield, and phenotypes of cows for milk proteins. beta-Casein declined and serum proteins increased with advancing age of cows. Concentration of individual proteins decreased during the first 2 to 3 mo in lactation and then increased as lactation progressed. alpha s1-Casein variants significantly affected concentrations of alpha s-casein (BC greater than BB greater than AB) and beta-lactoglobulin (AB greater than BB greater than BC). Variant B for beta-casein is associated with lower alpha s-casein, beta-lactoglobulin, immunoglobulins, and higher beta-casein and alpha-lactalbumin concentrations than variant A1, A2, or A3. Milk from BB kappa-casein, and BB beta-lactoglobulin cows contained more alpha s-casein, kappa-casein, and less beta-lactoglobulin than milk from AA cows for the two proteins. Concentrations of all proteins were negatively correlated with milk production. Increased somatic cell counts were associated with lower beta-casein and higher concentrations of other proteins. Fat content of milk was positively correlated with the three casein fractions and beta-lactoglobulin.

Association of milk protein types with growth and reproductive performance of dairy heifers

A total of 890 heifers was used to study the effects of four milk protein loci (alpha S1-casein, beta-casein, kappa-casein, and beta-lactoglobulin) on heifer growth and reproduction. The additive effects of gene substitutions at the four milk protein loci were significant only in 4 of 56 cases for all traits studied. Dominance effects at alpha S1-casein, beta-casein, and kappa-casein loci were not significant for any traits except beta-casein locus on body weight at first calving. Heifers with AB type of beta-lactoglobulin showed greater body weights and measurements and gestation length than the AA or BB type, indicating an overdominance effect. Heifers with AB type of beta-lactoglobulin were significantly younger at first conception and at first freshening and had fewer number of days from first service to conception than the AA or BB type, indicating underdominance effect. Thus, beta-lactoglobulin locus shows overdominance, underdominance, or no dominance, depending upon the traits considered. The four milk protein loci contributed more dominance variance than additive variance to total phenotypic variance. This might account for the existence of milk protein polymorphism in the cattle population. The combined genotypes of the four milk protein loci showed significant effects on 2 of 14 traits studied.

Surgery in long-term dialysis patients. Experience with more than 300 cases

Three hundred twelve surgical procedures in patients with chronic renal failure have been characterized. There is a high incidence of operation in this expanding population. Multiple procedures for each patient were found in our 10 year study. Operative mortality was 1 percent and late mortality was about 10 percent per year. The survival curve predicted an 81 percent 2 year rate and a 60 percent 5 year survival rate. The high late mortality was likely related to the underlying disease process and the high proportion of complicating associated illnesses. The gross complication rate was high (64 percent), with the most frequent one being hyperkalemia. Other frequent complications were hemodynamic instability, infections, and fluid overload. A pattern of postoperative time to onset for the various complications was identified. Perioperative management requires aggressive, but appropriate metabolic, hematologic, and pharmaceutical intervention.