Heteropaternal superfecundation frequently occurs in multiple-bearing mob-mated sheep.

Heteropaternal superfecundation may be defined as the fertilisation of two or more ova during the same oestrus cycle as a result of more than one coital act from different males; this results in foetuses being born in the same litter of the same age but different paternity. Heteropaternal superfecundation is more likely to occur in poly-ovulatory species like sheep; moreover, female sheep are often mob-mated with several rams concurrently, thus providing an opportunity for a given female to be served by multiple males during the same oestrus cycle. The objective of the present study was to determine the frequency of heteropaternal superfecundation in six sheep flocks where most of the ewes, lambs and rams were genotyped. A total of 685 multiple-birth litters were available where the sire, dam and all lambs were genotyped. Of the 539 pairs of twins included in the analysis, 160 (i.e. 30%) were sired by two different rams. Of the 137 sets of triplets included in the analysis, 73 (i.e. 53%) were sired by more than one ram. Of the nine sets of quadruplets, eight were sired by two rams with the remaining litter being mono-paternal. The overall incidence of heteropaternal superfecundation among litters was therefore 35%. Given that the incidence of multiple births in these flocks was 65%, heteropaternal superfecundation is expected to be relatively common in sheep; this is especially true as all but two of the litter-mates were polyzygotic. Genotyping of progeny is one practical solution to identity such individuals.

Bio-economic modelling of sheep meat production systems with varying flock litter size using field data.

Sheep meat producers derive the majority of income from sales of weaned lambs, determined by flock conception rates, litter size, and lamb survival. Field data from commercial flocks can inform sensitivity analyses of the effect of litter size on flock productivity, feed demand, and gross margin. This study adapted an established bio-economic model of a flock of breeding ewes informed by statistical relationships (from linear models) between flock litter size (lambs born per ewe lambing) and production factors (such as flock barren rate, litter birth type and lamb birth weight) identified using 156 145 animal records from the Irish national sheep breeding database. Sensitivity analyses were undertaken to investigate the effects of flock litter size on flock production, feed demand, and gross margin. Results showed that as flock litter size increased, the proportion of lambs born as multiples increased, with 14 % of lambs born as singles when flock litter size was 2.2 lambs born per ewe lambing. Flock gross margin increased from €2 205 to €7 730 as litter size increased from 1.0 to 2.0 lambs born per ewe lambing. As litter size increased from 1.0 to 2.2 lambs born per ewe lambing, flock gross margin increased linearly by, on average, €52 per 0.01 increase in litter size. At a litter size of > 2.2 lambs born per ewe lambing, flock gross margin increased on average €12 per 0.01 increase in litter size. At a litter size of 2.2 lambs born per ewe lambing, flock efficiency (at 65.0 kg of lamb weaned per ewe presented for breeding), weaning rate (at 1.5 lambs weaned per ewe presented for breeding; not including excess lambs from large litters sold within a week after birth and thus not weaned on-farm), and gross margin (at €8 500) began to plateau. The results indicate lower marginal returns in gross margin at very high flock litter size, due to the lower value of additional lambs born as triplets and quadruplets compared with single- and twin-born lambs. However, the diminishing economic returns occurred at higher flock litter size than are currently biologically achieved in most flocks. Quantification from this analysis demonstrates how the value of increasing the number of lambs born changes at very high flock litter size, which can inform the priorities and performance benchmarking for international sheep meat production industries.

Increased lower respiratory tract iron concentrations in alkaloidal ("crack") cocaine users.

STUDY OBJECTIVE: We hypothesized that the use of inhaled alkaloidal ("crack") cocaine could increase lung content of iron, either by inducing alveolar hemorrhage or by other mechanisms. Intrapulmonary accumulation of iron could promote chronic lung diseases in crack users. The goal of this study was to determine whether iron and ferritin content of alveolar macrophages or fluid recovered by BAL was increased in subjects using crack, compared with nonsmokers. METHODS: BAL was performed in 31 volunteer subjects, including healthy nonsmokers (n = 7), subjects smoking crack alone (n = 7), as well as subjects smoking both crack and cigarettes (n = 7) or cigarettes alone (n = 10). Iron content of alveolar macrophages and BAL fluid was determined by a colorimetric method and ferritin content of alveolar macrophages, and BAL fluid was measured by a two-sided immunoradiometric method. RESULTS: Alveolar macrophages recovered from crack users contained more iron than did alveolar macrophages from nonsmokers (25.4 +/- 2.9 nmol/10(6) vs 5.5 +/- 0.6 nmol/10(6) [mean +/- SE]; p < 0.01). There were similar increases in alveolar macrophage ferritin as well as BAL fluid iron and ferritin in crack users, compared with nonsmokers. BAL fluid ferritin concentrations in subjects smoking both crack and cigarettes were increased, compared with subjects smoking crack alone or cigarettes alone (p < 0.05). CONCLUSIONS: Use of crack increases intrapulmonary concentrations of iron and ferritin. Effects of crack on extracellular ferritin concentrations may be additive with effects of cigarette smoking. Although the mechanism(s) causing pulmonary iron accumulation were not identified by this study, it may be a result of occult alveolar hemorrhage or increased vascular permeability. The increase in lung iron burden in habitual crack users could promote chronic lung diseases in these subjects.

The private practice of rheumatology. The first 1,000 patients.

Although this report of the first 1,000 patients in a rheumatologic consultative private practice cannot necessarily reflect the general experience of rheumatology, certain conclusions may be valid and may help to guide the rheumatologist-in-training. Approximately 70% of our patients were categorized as having "inflammatory" or "connective tissue' disorders, rather than degenerative disorders. Internists and general practitioners were the principal referral sources. Over 80% of referrals came from a relatively small geographic radius of 10-15 miles. A population base of perhaps 200,000 people, therefore, may be necessary to support a purely rheumatologic practice. A relatively steady flow of 2 new patients per day was not significantly influenced by subsequent additional rheumatologists moving into the area. However, the pattern of referrals clearly changed to include more patient-to-patient referrals (nearly 30%), perhaps reflecting both loss of physician referral sources and the increasing number of referrals from satisfied patients over a period of time.

Seronegative systemic lupus erythematosus.

The diagnosis of systemic lupus erythematosus (SLE) often depens on positive tests for antinuclear antibody, LE cells, and antibody to DNA. In fact, the presence of such serological markers is virtually required for the diagnosis of active disease. This report describes 5 well-studied patients with SLE who initially presented with negative serology despite active multisystemic disease. When followed from 10 months to 7 yr, negative serologic markers, including the ANA, LE cell test, and anti-DNA were seen to change from negative to positive, analogous to the seronegative rheumatoid patient who may become seropositive. In a few cases of lupus, therefore, negative serologic tests do not always exclude SLE, and serial testing at periodic intervals may be indicated.

Granulomatous liver disease and giant cell arteritis. Case report and literature review.

A case granulomatous liver disease associated with the polymyalgia rheumatica-giant cell arteritis syndrome is presented. Treatment with corticosteroids resulted in prompt improvement in both the polymyalgia rheumatica-giant cell arteritis syndrome, as well as the tests of liver function. It is suggested that polymyalgia rheumatica and giant cell arteritis may involve the liver and should be included in the differential diagnosis of granulomatous liver disease.

Hemichorea, moya-moya, and ulcerative colitis.

This is a case report linking chorea, colitis, and moya-moya. The clear involvement in the vasculopathy of the basal ganglia offers an obvious substrate for the movement disorder.

Muscle disease in progressive systemic sclerosis: diagnostic and therapeutic considerations.

Upon careful examination, 23 of 24 patients with progressive systemic sclerosis (PSS) were found to have abnormalities of muscle. Nineteen patients presented a homogenous pattern of muscle abnormalities, which untreated was associated with a stable course ("simple myopathy"). Three patients demonstrated inflammatory muscle disease indistinguishable from polymyositis while a fourth patient developed marked weakness associated with a generalized neuropathic process. Muscle enzymes, electromyogram, and muscle biopsy permitted distinction among the different muscle disorders, a distinction that could have prognostic and therapeutic importance.

Attosecond synchronization of high-harmonic soft x-rays.

Subfemtosecond light pulses can be obtained by superposing several high harmonics of an intense laser pulse. Provided that the harmonics are emitted simultaneously, increasing their number should result in shorter pulses. However, we found that the high harmonics were not synchronized on an attosecond time scale, thus setting a lower limit to the achievable x-ray pulse duration. We showed that the synchronization could be improved considerably by controlling the underlying ultrafast electron dynamics, to provide pulses of 130 attoseconds in duration. We discuss the possibility of achieving even shorter pulses, which would allow us to track fast electron processes in matter.

Optimization of attosecond pulse generation.

The generation of attosecond pulses by superposition of high harmonics relies on their synchronization in the emission. Our experiments in the low-order, plateau, and cutoff regions of the spectrum reveal different regimes in the electron dynamics determining the synchronization quality. The shortest pulses are obtained by combining a spectral filtering of harmonics from the end of the plateau and the cutoff, and a far-field spatial filtering that selects a single electron quantum path contribution to the emission. This method applies to isolated pulses as well as pulse trains.