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Biomedical subjects

E J Smith

Publications and source records attributed to E J Smith.

At least 73 records · Page 4Linked to original sources
PubMed1994

Ulysses charged particle measurements between 1 and 5 AU from the sun.

Proton fluxes obtained by two instruments carried on the ESA/NASA Ulysses spacecraft are reported for the period from launch in October 1990 till Jupiter encounter in February 1992. Proton energy ranges are 24-59, 71-99, 130-320, 320-2100 and > 2100 MeV. The Sun was very active during this period, the events of March 1991 being some of the largest of the solar cycle. The relationship between events on the Sun and the observed proton flux is discussed.

Electrons↗
PubMed1994

The prevalence of femoral osteolysis associated with components inserted with or without cement in total hip replacements. A retrospective matched-pair series.

The prevalence of femoral osteolysis in hips in which a femoral component had been inserted without cement was compared with that in hips with a cemented component, in a retrospective matched-pair study of the results of primary total hip arthroplasties; all patients had received the same type of acetabular component. Forty-one hips in thirty-nine patients who had a Harris-Galante porous-coated total hip prosthesis without cement were matched by age, sex, weight, duration of follow-up, and diagnosis with forty-one hips in thirty-eight patients who had a hybrid total hip reconstruction; the hybrid reconstruction consisted of the same acetabular component and a Precoat femoral component inserted with a so-called third-generation cementing technique. All of the operations were done by the same surgeon, who used the same operative approach and the same course of postoperative rehabilitation. All of the patients were followed for at least four years (mean, six years). Osteolysis developed in twelve (29 percent) of the hips that had a femoral component without cement compared with none of the hips that had a cemented component (p < 0.0002). At the latest follow-up examination, none of the femoral components that had been inserted with cement were loose and none had been revised, while eight (20 percent) of the femoral components that had been inserted without cement were loose and five (12 per cent) had been revised. This retrospective matched-pair study controlled for many of the variables associated with a comparison of the rates of femoral osteolysis in separate series of femoral components fixed with and without cement.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Male-mediated venereal transmission of endogenous avian leukosis virus.

Congenital transmission of avian leukosis viruses (ALV) occurs readily through the egg, but transmission of ALV through male seminal fluid is considered to be nonexistent or rare. Progeny from mating endogenous late-feathering (LF), K/k+ males carrying an endogenous virus gene (ev21) with virgin early-feathering (EF) k+/w females were examined for the presence of infectious endogenous virus EV21 using an enzyme-labeled immunoassay for viral capsid antigen p27. All 177 LF chicks expressed EV21, p27, and 171 of 175 EF chicks did not express p27. Blood from the four p27-positive EF chicks revealed only infectious Subgroup E ALV as determined by subgroup-specific virus assays. Southern blot DNA hybridizations, however, ruled out germline integration of EV21 among the four infected EF progeny. Virus EV21 was not shed in albumens of the dams. Moreover, antibodies against ALV Subgroups A and E were not detected in dams 17 wk after the first insemination. Chicks infected with EV21 were found only in the first two of six hatches. Data suggested direct infection of the embryos from viremic semen rather than congenital infection through infected hens. Direct male transmission of EV21 to progeny may be the basis for persistence of refractory lines noted in some ALV eradication programs. Based on the absence of recombinants among 352 progeny, ev21 and K appear to be less than .3 cM apart.

Animals↗
PubMed1994

Determination of the zygosity of ev21-K in late-feathering male White Leghorns using the polymerase chain reaction.

The dominant sex-linked late-feathering (LF) gene, K, is of commercial importance for sex determination at hatch. Knowledge of the zygosity of sequences associated with K would enable breeders to more efficiently select homozygous grandparent LF males on the maternal side of the standard feather-sex cross because all of their progeny would be LF, whereas only half of the progeny from heterozygous grandparent males would be LF. A specific, polymerase chain reaction (PCR) assay is described that distinguishes White Leghorn K/K males from K/k+ males and obviates the need to raise all LF grandparent males to sexual maturity. Because the Z chromosome of some LF broiler breeders have, in addition to the endogenous virus gene, ev21, the wild type allele, which is termed the unoccupied repeat b (URb), this approach may not be applicable to some broiler lines.

Alleles↗
PubMed1993

Some effects of nutrition and management on the fertility of dairy cattle.

When 24 cows were classified according to whether they had a better or worse energy status (defined as a plasma beta-hydroxybutyrate level below or above 15 mg/100 ml and a plasma glucose level above or below 55 mg/100 ml) the median interval between calving and the onset of cyclicity was shorter and conception rates were better for the cows with a better energy status at seven and 14 days after calving. This was not repeated when the cows' energy status was assessed as better at either 21 days after calving or at the time of service. In the same group of cows there was a positive correlation between the loss of condition score in early lactation and beta-hydroxybutyrate levels. In a further trial 15 cows fed a silage-based diet during the dry period had better conception rates and greater luteinising hormone responses to buserelin than 14 cows fed a straw-based diet. The straw-fed cows lost more weight before calving and had significantly higher non-esterified fatty acid levels. After calving both groups of cows were fed the same diet but the cows fed straw in the dry period produced less milk and lost less weight than the cows fed silage. Dry cow nutrition affected subsequent fertility and production. The non-esterified fatty acid level in the last week or two of pregnancy is suggested as a practical indication of the level of dry cow nutrition and its probable effect on productivity. No relationships were observed between plasma urea concentrations and the fertility of the cows.

3-Hydroxybutyric Acid↗
PubMed1993

Interactions of the p107 and Rb proteins with E2F during the cell proliferation response.

The E2F transcription factor is found in complexes with a variety of cellular proteins including the retinoblastoma tumor suppressor protein. Various assays have demonstrated a tight correlation between the functional capacity of Rb as a growth suppressor and its ability to bind to E2F. Moreover, only the underphosphorylated form of Rb, which appears to be the active species, interacts with E2F. Despite the fact that the majority of Rb becomes hyperphosphorylated at the end of G1, we now show that the E2F-Rb interaction persists through the G1/S transition and into S phase. A distinct E2F complex does appear to be regulated in relation to the transition from G1 to S phase. We now demonstrate that this complex contains the Rb-related p107 protein. Moreover, like the Rb protein, p107 inhibits E2F-dependent transcription in a co-transfection assay. This result, together with the observation that free, uncomplexed E2F accumulates as cells leave G1 and enter S phase, suggests that the p107 protein may regulate E2F-dependent transcription during G1. In contrast, although Rb does regulate the transcriptional activity of E2F, this association does not coincide with the G1 to S phase transition.

3T3 Cells↗
PubMed1993

Post-traumatic osteoporosis and algodystrophy after external fixation of tibial fractures.

The incidence of two forms of post-traumatic osteoporosis and algodystrophy in the ankle region of 20 patients with displaced diaphyseal fractures of the tibia treated with external fixation were studied. Acute localised osteoporosis (ALO) occurred in 14 (70 per cent) and 5 (25 per cent) developed algodystrophy. ALO was significantly less frequent in matched patients treated by internal fixation or by external plaster-of-Paris (POP) cast. Regional osteoporosis (RO) was most common in POP patients. The presence of ALO may indicate the development of algodystrophy following tibial fracture. Our findings suggest that external fixation may predispose to ALO and algodystrophy.

Acute Disease↗
PubMed1993

Algodystrophy and osteoporosis after tibial fractures.

We made a prospective study of the incidence and natural history of algodystrophy and associated changes in bone mineral density in the ankles and feet of 60 consecutive patients who had suffered unilateral fractures of the tibial shaft. At bone union, 18 patients showed signs of algodystrophy. Its development was independent of the type of fracture management and of the severity of injury. Patients with algodystrophy lost significantly more bone mineral than did those without but the degree of this loss was independent of the type of treatment and of the time to fracture union. In most cases the symptoms resolved within six months of fracture union but in four patients they were still present at one year and two of these had not returned to work.

Absorptiometry, Photon↗
PubMed1993

Effect of tumor virus susceptibility alleles on the late-feathering gene K on early growth of White Leghorns.

The influence of tumor virus susceptibility (tvb) alleles and the sex-linked, late-feathering-endogenous virus 21 complex (K-ev21) on early growth was observed in progeny from late-feathering (LF) and early-feathering (EF) dams. At 2, 4, 6 and 10 wk of age, homozygous (K/K) males that carried a dominant tvbs1 allele were significantly (P < .05) lighter in total body weight than K/K homozygous endogenous virus (EV) EV21-resistant (tvbr/tvbr) hatchmates. Among heterozygous (K/k+) males, tvbs1 did not significantly influence growth when compared with tvbr/tvbr hatchmates. At 10 wk of age, tvbs1-positive K/w female progeny from LF dams were also significantly lighter than tvbr/tvbr K/w hatchmates. However, among progeny from EF dams no significant within sex differences in body weight were found regardless of their feather or EV susceptibility phenotype. Results indicate that susceptibility to EV21 infection is particularly detrimental to early growth of ev21-K homozygous male and hemizygous female progeny of LF dams.

Alleles↗
PubMed1993

Research note: a rapid method for the detection of the Rous-associated endogenous solitary long terminal repeat, ev15.

A rapid method has been developed for the detection of the solitary long terminal repeat ev15, a member of the avian leukosis virus (ALV) family of endogenous viral elements (ev genes) in chickens. Detection is accomplished by a polymerase chain reaction (PCR) assay that can be performed on purified genomic DNA samples or crude preparations of partially purified whole blood lysates. The test discriminates unambiguously between birds that are homozygous ev15-, homozygous ev15+, or heterozygous ev15-/ev15+. The incorporation of a modified touchdown amplification profile significantly improved the specificity of the PCR assay. Small-scale screening of birds from a variety of chicken breeds has revealed that ev15 is present in populations of both egg-strain birds and broilers.

Animals↗
PubMed1992

A comparison of four methods of variance component estimation for heritability of embryonic mortality in turkeys.

A comparison of four methods for variance component estimation to compute heritability of embryonic mortality in the early (Days 1 to 10) and late (Days 21 to 28) incubation period, was performed using Henderson's Method 3, maximum likelihood (ML), restricted maximum likelihood (REML), and minimum variance quadratic unbiased estimator (MIVQUE). Incubation records from Wrolstad Medium White turkeys divergently selected for semen ejaculate volume were the source of data for the present study. Negative sire components of variance were obtained for early mortality by both Henderson's Method 3 and the MIVQUE procedure. Estimates of the sire variance component for the late mortality period were lower (P less than .05) for ML than those obtained using Henderson's Method 3, REML, and MIVQUE. It was concluded that likelihood procedures (ML and REML) are superior for estimating variance components and genetic parameters from unbalanced data.

Analysis of Variance↗
PubMed1992

Genetic variation in total plasma and high density lipoprotein cholesterol and body weight in medium white turkeys.

Plasma total cholesterol (PC) and its high density lipoprotein cholesterol (HDLC) fraction were determined in 700 16-wk-old Medium White turkeys in Generation 15 of selection for low and high semen ejaculate volumes (SEV). The birds examined were from pedigree matings involving 10 sires mated to 100 dams in each line. Mean PC and HDLC were not different between lines and between sexes within lines. Genetic parameters were estimated for PC, HDLC, and BW. Sire component heritabilities estimated based on pooled data from low and high SEV lines for PC and HDLC were -.03 and .26, respectively. Genetic correlations were .05 between PC and HDLC; .13 between PC and BW; and -.34 between HDLC and BW. It was concluded that variation in PC in 16-wk-old Medium White turkeys is largely due to environmental variation and that the genetic component is largely nonadditive. However, a moderate additive genetic component was observed for HDLC. Further, determination of total PC and HDLC at 16 wk of age does not exhibit a potential value as an indicator of future SEV potential.

Animals↗
PubMed1992

Classification of turkeys as low or high volume semen producers using discriminant analysis.

Medium White turkeys in Generation 10 of divergent selection for semen ejaculate volume (SEV) were classified into lines that produce either low or high volumes of semen using a multivariate statistical technique, discriminant analysis. The discriminant function was based on records of hen fertility, embryonic mortality in the early and late incubation periods, and the incidence of pipped eggs. A hit ratio, the proportion of birds correctly categorized as low or high, of .60 was obtained. The discriminant function was subsequently used to classify birds in Generation 12. A misclassification rate of .28 and .48 was obtained for birds in the low and high lines, respectively. It was concluded that the relatively low rates of misclassification indicate a potential method for identifying male and female turkeys as belonging to low or high SEV lines, based on fertility and incubation records.

Animals↗
PubMed1991

Maxillofacial trauma in severely injured patients.

A study was made of maxillofacial trauma in seriously injured patients to determine the likely role of oral and maxillofacial surgeons working in the regional trauma centres proposed by the Royal College of Surgeons of England. There were 153 patients, aged 70 years or less, who sustained major trauma (injury severity score 16 or more) and were admitted directly to the accident departments of the Bristol Royal Infirmary or Derriford Hospital, Plymouth during 1989. Maxillofacial injuries occurred in 50 (33%) of these patients with lacerations present in 39, burns in 1 and facial bone fractures in 28 (18%); soft tissue abrasions and contusions were excluded. The aetiology, patterns of injury, surgical treatment and outcome were reviewed. The implications for the provision of maxillofacial surgical services in regional trauma centres is discussed.

Accidents, Traffic↗
PubMed1991

Performance of early and late feathering broiler breeder females with different feeding regimens.

1. Growth, reproductive characteristics and immunocompetence were evaluated in a line of broiler breeder females segregating at the sex-linked feathering locus when maintained on three feeding regimens with two forms of food in a factorial design. 2. Long-term obesity but not short-term weight gain had deleterious consequences for reproductive characteristics, response to sheep red blood cell antigen, resistance to Escherichia coli and livability. 3. Reproductive performance of early feathering females was superior to that of late feathering ones. Differences were attributed to an association between the allele for late feathering and an endogenous viral locus ev21, which encodes for avian leucosis virus. 4. Reproductive performance of breeders fed crumbles was superior to that of breeders fed a combination of crumbles and fines.

Animal Feed↗
PubMed1991

The influence of ev6 on the immune response to avian leukosis virus infection in rapid-feathering progeny of slow- and rapid-feathering dams.

Endogenous virus (EV) locus ev6 encodes only virus envelope glycoprotein. The influence of ev6 on the immune response to contact infection with hatchmates infected with avian leukosis virus (ALV) was compared in replicate hatches. The ALV Subgroup E-resistant, rapid-feathering (RF) female chickens produced by slow-feathering (SF) and RF dams with and without ev6 were exposed at hatch to hatchmates infected with ALV Subgroup A (Strain RPL-40). The RPL-40 viremia, shedding, and virus neutralizing antibodies were measured among pullets from two hatches at 22 wk of age. Although significant (P less than .05) differences between hatches in the immune response to contact infection were noted among ev6+ pullets, significantly fewer ev6+ pullets seroconverted than their ev6- hatchmates. At 22 wk of age, significantly more lymphomas were also found among ev6+ pullets than among ev6- hatchmates. In flocks wherein both parents and progeny were homozygous resistant to Subgroup E virus, there was no deterimental maternal effect on RF progeny from SF dams that carried ev21. These results also confirm that selection for genetic cellular resistance to Subgroup E ALV infection eliminates congenital transmission of EV21.

Animals↗