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Biomedical subjects

E Hare

Publications and source records attributed to E Hare.

At least 19 recordsLinked to original sources
PubMed2006

Trends in calving ages and calving intervals for dairy cattle breeds in the United States.

Trends since 1980 for calving age and calving interval, 2 factors that influence herd life, were examined by parity for 5 breeds of US dairy cattle. Calving data were from cows with records that passed edits for USDA genetic evaluations and were in herds that remained on Dairy Herd Improvement test. First-calf heifers calved at progressively younger ages over time, but the age decline was less for later parities because of longer calving intervals. Breed differences for calving age were evident for all parities; current mean age at first calving ranged from 24 mo for Jerseys to 28 mo for Ayrshires. Mean calving age across all parities declined over time for all breeds, primarily because of increased turnover rate, and ranged from 48 mo for Holsteins to 54 mo for Ayrshires. Across parity, annual increase in calving interval was reasonably consistent (0.90 to 1.07 d/yr) for all breeds except Jersey (0.49 d/yr). Within parity, regressions of calving interval on year were generally similar to overall breed trend. Breed means for first calving interval across time ranged from 390 d for Jerseys to 407 d for Brown Swiss.

Aging↗
PubMed2006

Survival rates and productive herd life of dairy cattle in the United States.

Survival rates and productive herd life were examined for 13.8 million US dairy cows that calved from January 1, 1980, through March 2, 2005. Cows that left the herd for dairy purposes or were from herds that discontinued Dairy Herd Improvement testing were excluded from any calculations to prevent underestimation of population longevity. Mean lactation length for cows without subsequently recorded lactations ranged from 205 to 235 d across breed-parity subsets and were 4 to 29 d longer for parities 2 through 7 than for parity 1. Mean survival rates were 73% to parity 2; 50% to parity 3; 32% to parity 4; and 19, 10, 5, and 2% to parities 5 through 8, respectively. The mean number of parities for Holsteins declined from 3.2 for those first calving in 1980 to 2.8 for those first calving in 1994. Mean numbers of parities for other breeds first calving in 1994 were 2.9 for Ayrshires and Brown Swiss, 2.4 for Guernseys, and 3.2 for Jerseys. Breed means for productive herd life (through parity 8) ranged from 28 to 36 mo. All regressions of mean number of parities or mean productive herd life on year were negative. The trend for decline of many of those indicators of longevity slowed or ended after the early 1990s. Between 31 (Jersey) and 39% (Guernsey) of herds were made up of first-calf heifers.

Animals↗
PubMed2004

Left ventricular systolic function and diastolic filling after intermittent high intensity team sports.

BACKGROUND: Prolonged steady state exercise can lead to a decrease in left ventricular (LV) function as well as promote the release of cardiac troponin T (cTnT). There is limited information on the effect of intermittent high intensity exercise of moderate duration. OBJECTIVES: To determine the effect of intermittent high intensity exercise of moderate duration on LV function. METHODS: Nineteen male rugby and football players (mean (SD) age 21 (2) years) volunteered. Assessments, before, immediately after, and 24 hours after competitive games, included body mass, heart rate (HR), and systolic blood pressure (sBP) as well as echocardiography to assess stroke volume (SV), ejection fraction (EF), systolic blood pressure/end systolic volume ratio (sBP/ESV), and global diastolic filling (E:A) as well as to indirectly quantify preload (LV internal dimension at end diastole (LVIDd)). Serum cTnT was analysed using a 3rd generation assay. Changes in LV function were analysed by repeated measures analysis of variance. cTnT data are presented descriptively. RESULTS: SV (91 (26) v 91 (36) v 90 (35) ml before, after, and 24 hours after the game respectively), EF (71 (8) v 70 (9) v 71 (7)%), and sBP/ESV (4.2 (1.8) v 3.8 (1.9) v 4.1 (1.6) mm Hg/ml) were not significantly altered (p>0.05). Interestingly, whereas LVIDd was maintained after the game (50 (5) v 50 (6) mm), sBP was transiently but significantly reduced (131 (3) v 122 (3) mm Hg; p<0.05). E:A was moderately (p<0.05) reduced after the game (2.0 (0.4) v 1.5 (0.4)) but returned to baseline within 24 hours. No blood sample contained detectable levels of cTnT. CONCLUSIONS: In this cohort, LV systolic function was not significantly altered after intermittent activity. A transient depression in global diastolic filling was partially attributable to a raised HR and could not be explained by myocyte disruption as represented by cTnT release.

Adult↗
PubMed2004

Duration of herd participation in dairy herd improvement milk recording in the United States.

Participation in milk-recording programs that provide data for national genetic evaluations of dairy cattle in the United States is voluntary, but the effectiveness of the evaluation system increases with the number of herds that contribute data. To investigate patterns of herd participation in Dairy Herd Improvement (DHI) testing, periods of continuous testing were computed based on the year that a herd initiated or terminated testing and by geographical region. Continuous testing was defined as at least one test per 6-mo period. Some herds discontinued testing and then re-enrolled. Across all years (1960 through 2002), 65% of herds had one period of continuous testing (no testing lapse). The percentage of herds with testing lapses decreased as the number of lapses increased and as the initial test year became more recent; overall, only 1.5% of herds had more than 6 continuous testing periods. For herds that terminated DHI testing from 1960 through 2002, 64% were on continuous test for <3 yr. In general, herd frequencies decreased as continuous test period increased except for continuous testing of > or =20 yr, which increased to 13% for years 2000 to 2002. Herds with more recent termination dates had remained on continuous test longer, and one-third of herds that were still on test after June 2002 had been on test for at least 20 yr. The duration of herd participation was longest for the northeastern and mideastern United States and shortest for the southeastern United States. Multiple periods of testing with lapses of >6 mo between test periods represent a loss of data that could have enhanced the study and evaluation of genetic characteristics of US dairy cattle.

Animals↗
PubMed2001

Sperm output and hormone concentrations in Finn and Dorset rams exposed to long- and short-day lighting.

Seasonal changes in photoperiod have a substantial effect on sexual behavior and reproduction in rams. Little information is available on sperm output from high libido versus average libido rams subjected to intensive semen collection while being exposed to controlled short versus long photoperiods. Six Finn and six Dorset rams were compared in a reversal design, which allowed rams of both breeds to be exposed to 8 h versus 16 h of light. During each of two 84-d periods rams were subjected twice to an initial depletion of epididymal sperm reserves by collecting up to 26 ejaculates of semen in 3 d, followed by up to 10 ejaculates per day, 1, 3, 5, and 7 d after the initial depletion. A total of 2673 semen samples were collected. Nearly twice as many ejaculates (63.6% of the total) were obtained from Finn rams as from Dorset rams during both the initial and subsequent 3-d sperm depletion periods. This difference in libido was associated with obtaining 33.6 +/- 3.1 x 10(9) sperm from Finn rams versus 10.0 +/- 2.2 x 10(9) sperm from Dorset rams during the initial depletion period (P<0.05). Changes in photoperiod did not affect sperm output (P>0.05) in Finn rams, but may have affected Dorset rams. With 16 h of light, prolactin was significantly (P<0.05) increased in both breeds, particularly in Finn rams. Testosterone in both breeds followed an endogenous rhythm, not affected by the change in controlled photoperiods.

Animals↗
PubMed2001

Blood catalase and haematocrit values in a breeding colony of Dutch-belted rabbits.

Rabbit seminal plasma catalase is much higher than in the semen of other mammals, and differences appear to be inherited. Because of the scarcity of information on rabbit blood catalase and haematocrit in Dutch-belted rabbits, an investigation of possible effects of gender, age and genetics on these variables was undertaken. There were 191 rabbits sampled at 2-3 months, 130 at 12 months and 61 at 18-24 months of age. There was no age effect on the haematocrit values and on blood catalase activity. At 12 months of age males had an average haematocrit value of 44% compared with 40% for females (P < 0.05). Corresponding average catalase values were 431 and 356 units/ml of blood (P < 0.05). Also catalase was measured in the semen and blood of 34 males, and males differed in both their blood and semen catalase activity (P < 0.05). The correlation between the two traits was r = 0.44. Heritability (h2) estimates, based on 231 rabbits were 0.40 for blood catalase activity, and 0.26 for haematocrit. The genetic correlation between the two variables was 0.83 (P < 0.05). These studies are consistent with the literature in that female rabbits have a slightly lower haematocrit value than males, and this is associated with a lower catalase activity. This appears to be the first report of a study that compares rabbit blood catalase in males and females of different ages. Preliminary evidence that differences may have a heritable basis is consistent with previous studies on rabbit semen catalase.

Age Factors↗
PubMed2000

Development and application of a GFP-FRET intracellular caspase assay for drug screening.

Apoptosis is a crucial biological process, and activation of caspase endoproteases is essential for proper regulation and execution of apoptosis. Because caspases also appear to be central players in several pathological states, there is a practical need within the biopharmaceutical research community for facile, noninvasive cellular assays for the discovery of compounds that modulate caspase activity. Tandem molecules of green fluorescent protein (GFP) stably expressed within cells can serve as a genetically encoded sensor of protease activity. Using this technology, we have developed a stable cellular system for the screening of agents that modulate activation of the caspase cascade. This assay technology allows for the real-time monitoring of apoptosis in situ, using conventional fluorescent plate reader detection. By applying this assay system to an actual compound screen, small-molecule inducers of cell apoptosis were reliably identified. Follow-up pharmacology confirmed that the rank-order potency of primary hits using the intracellular GFP assay corresponded to that found using a conventional, cell lysis-based assay method.

Amino Acid Sequence↗
PubMed1991

The history of 'nervous disorders' from 1600 to 1840, and a comparison with modern views.

In the 18th century the main varieties of nervous illness - hypochondria, hysteria, the spleen, the vapours and dyspepsia - became included under the general term 'nervous disorders'. When no physical disorder of the nerves could be detected in such conditions, the hypothesis of nervous disorder was replaced by the more vague concept of 'nervous temperament'. The fact that there is still no evidence of pathological change in such cases continues to expose physicians to the alternative hypothesis of a purely psychological cause. The modern era in our understanding of the nervous system may be said to date from 1843 when Du Bois Reymond showed the electrical nature of nervous conduction. The publication of Jorden's Briefe Discourse in 1603 may be taken to represent the start of a discrete period (1600 to 1840) in the history of neurotic illness.

Dyspepsia↗
PubMed1988

Schizophrenia before 1800? The case of the Revd George Trosse.

Trosse's account of his life has been described as one of the strangest pieces of realism in the English language. It gives a detailed description of the author's personal experience of three episodes of psychotic disorder during the years 1656-7. The disorder has been considered an early instance of schizophrenia, but evidence is presented here to suggest that a more plausible diagnosis was alcoholic psychosis and affective disorder.

England↗
PubMed1988

Schizophrenia as a recent disease.

The hypothesis that schizophrenia is a recent disease can explain why descriptions of schizophrenia-like disorders were rare before 1800, why the prevalence of insanity in the Western world increased during the 19th but remained low in the non-Western world until the 20th century, and why schizophrenia has become milder in the West during recent decades. It also explains why schizophrenia has 'persisted' in spite of its associated low fertility. The evidence for the hypothesis is somewhat frail, but perhaps not more so than that for alternative hypotheses.

History, 18th Century↗
PubMed1986

Aspects of the epidemiology of schizophrenia.

Reasons are given why the hospital diagnosis of schizophrenia may be accurate enough for the proper study of certain aspects of its epidemiology. Studies in the seasonality of admissions and of births in schizophrenic patients have produced consistent results in different countries and at different times. The results are summarized, and causal hypotheses based on them are discussed. The idea that schizophrenia is a relatively recent disease is compatible with these hypotheses.

England↗
PubMed1981

A relation between seasonal temperature and the birth rate of schizophrenic patients.

The relation between schizophrenia birth rates and environmental temperature was studied in patients born in England and Wales during 1921-1955 and first admitted there in 1970-1977. A methodological difficulty due to varying age-incidence was avoided by the use of indices independent of yearly changes in rates. Birth rates in the second quarter and in the first half of the year showed high negative correlations with mean temperatures of the first quarter and first half of the year. Comparison of years with the coldest and with the warmest seasons showed the schizophrenia birth rate to be consistently higher in the coldest years. No comparable relations between birth rates and temperature were found for patients with affective psychosis, neurosis or personality disorder. The findings indicate an association between schizophrenia birth rates and temperature of a kind similar to that between infant death rates and temperature during the years 1921-55. Some implications are discussed.

Age Factors↗