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Biomedical subjects

L H Thomas

Publications and source records attributed to L H Thomas.

At least 91 records · Page 5Linked to original sources
PubMed1981

Hydrogenated oils and fats: the presence of chemically-modified fatty acids in human adipose tissue.

A total of 231 samples of adipose tissue has been analyzed for trans unsaturated acids which arise in large measure via consumption of hydrogenated fat; 136 specimens derived from patients who had died of ischemic heart disease (cases), the remainder being controls. They have also been analyzed by gas-liquid chromatography which gave information regarding the amounts of 1) "higher acids"--C20 plus C22 acids, mainly monoenoic--which derive from hydrogenated marine oils present in high amounts in certain margarines in the United Kingdom, and 2) "lower acids"--14:1 plus odd-numbered and branched chain acids in the C15 to C17 range--which are present in hydrogenated fat in lower amounts than in, say, butter-fat. Values of trans unsaturated acids tend to be higher, and values of lower acids lower for cases than controls, but we cannot at present conclude that these differences are statistically significant. Case versus control levels in respect of higher acids and linoleic acid do not appear to be significantly different.

Adipose Tissue↗
PubMed1981

Ischaemic heart disease and the proportions of hydrogenated fat and ruminant-animal fat in adipose tissue at post-mortem examination: a case-control study.

Fatty acids characteristic of ruminant-animal fat have been found to be present in significantly lower proportions in samples from the depot fat of persons dying of ischaemic heart disease (cases) than in specimens from persons dying of unrelated causes (controls). Although such acids are also present, in lesser amounts, in hydrogenated marine oils, this case-versus-control difference is difficult to explain other than on the basis that controls consumed a higher proportion of ruminant-animal fat in their total dietary fat than did the cases. The proportions of polyunsaturated acids and of certain higher (C20 and C22 mostly mono-enoic) acids in the depot fat of cases and controls are virtually identical. There is also no indication of any difference in degrees of saturation of fats between the case and control specimens.

Adipose Tissue↗
PubMed1980

The possible role of respiratory syncytial virus and Pasteurella spp in calf respiratory disease.

In a natural outbreak of respiratory disease during 1976, 31 of 43 calves showed moderately severe clinical signs which included pyrexia (maximum 42 degrees C) and tachypnoea. During the outbreak infection by respiratory syncytial virus (RSV) was demonstrated by isolation from nasopharyngeal swabs or by serology. Pasteurella haemolytica or P multocida were isolated from the blood of four and five calves respectively. In the month before disease 65 per cent of the calves showed significant antibody responses to P haemolytica. However a similar serological response to P haemolytica was demonstrated during 1975 in a comparable group of calves in which no disease and no infection with RSV was detected. No serological response to P multocida was demonstrated in either year. The temporal correlation of RSV infection with respiratory disease in the group of 43 calves was striking but the evidence neither reinforced nor discounted the possibility of interaction between RSV and P haemolytica infection in the pathogenesis of disease.

Animals↗
PubMed1980

Experimental infection of calves with two strains of bovine virus diarrhoea virus: certain immunological reactions.

Certain immunological responses of 4-6 month old calves experimentally inoculated with either cytopathic or non-cytopathic bovine virus diarrhoea virus (BVDV) were compared with those of uninfected control calves. The tests used to demonstrate the immunological responses were the transformation of lymphocytes by PHA mitogen, the percentage of lymphocytes with surface immunoglobulin, and the antibody titres induced by an intravenous inoculation of killed Brucella abortus. There were no significant differences between the two groups of calves and therefore, the mild experimental disease produced by BVDV did not appear to affect adversely the immunological response.

Animals↗
PubMed1980

A survey of virus infections of the respiratory tract of cattle and their association with disease.

A total of 1590 caves were investigated between May 1972 and December 1975. Twenty-two per cent were treated for respiratory disease and 2 . 5% died of pneumonia. Almost 80% of the respiratory illness occurred in six sharp outbreaks. Samples of virology were collected routinely from 127 healthy calves and from 354 calves treated for respiratory signs and comprised 1143 nasopharyngeal swabs and 1069 sera. Virus infections were detected on 540 occasions including 135 by parainfluenzavirus type 3 (Pi-3), 78 by respiratory syncytial virus (RSV), 103 by rhinovirus, 49 by bovine virus diarrhoea virus (BVDV), 29 by adenoviruses, 53 by reoviruses and 88 by enteroviruses. The seasonal and age distribution of infections differed between viruses. Only infections by RSV, Pi-3 and BVDV were significantly associated with disease.

Adenoviridae Infections↗
PubMed1980

Experimental infection of calves with two strains of bovine virus diarrhoea virus: virus recovery and clinical reactions.

Fifteen calves were inoculated with a mixture of two strains of bovine virus diarrhoea virus (BVDV), the cytopathogenic NADL strain which had been passaged over 20 times n vitro, and the non-cytopathogenic FCS strain, passaged only once after isolation from fetal calf serum. In a second experiment, seven calves received the NADL strain, and eight the FCS strain. The clinical and virological results of the two experiments were compared. In dual infections, the NADL strain interfered with the replication of the FCS strain resulting in less severe disease than the FCS strain alone. The FCS-BVDV was recovered from nasopharyngeal swabs and buffy coat cells whereas the NADL-BVDV was recovered only from nasopharyngeal swabs. The cytopathogenicity of the two strains did not change after passage in vivo. The differences observed are discussed in relation to cultural history and cytopathogenicity.

Animals↗
PubMed1979

Pathogenicity of some Mycoplasma and Acholeplasma species in the lungs of gnotobiotic calves.

Cloned cultures of 16 strains, representing nine different species of Mycoplasma and Acholeplasma, were inoculated intratracheally into gnotobiotic calves. Strains of M bovirhinis, M canadense, M verecundum, A axanthum and A modicum did not produce visible pneumonic lesions and were not reisolated from the lungs. Strains of M alkalescens and M arginini colonised the lower respiratory tract but failed to produce visible pneumonia. M bovigenitalium (strain M991/70) and M dispar (strain Gri226) both colonised the respiratory tract and induced pneumonic lesions estimated to involve up to 8 per cent (M bovigenitalium) and 17 per cent (M dispar) of the lung. Histologically M bovigenitalium produced a cuffing pneumonia and M dispar produced a interstitial alveolitis.

Acholeplasma↗
PubMed1978

An inactivated parainfluenza virus type 3 vaccine: the influence of vaccination regime on the response of calves and their subsequent resistance to challenge.

Calves maintained in insolated pens were vaccinated with an inactivated parainfluenza virus type (3) (pi3) vaccine usingparenteral and local route singly and in combination. The calves were subsequently monitored for serum antibody response and challenged intranasally with live virus to assess the protection derived from vaccination. Calves receiving one subcutaneous dose of vaccine in oil adjuvant produced a marked antibody response and were partially protected against challenge. Those receiving two successive subcutaneous doses produced a much greater antiboyd response and were completely protected against challenge. One intranasal dose of aqueous vaccine failed elicit a significant serum antibody response or protection against challenge. However, there was some evidence that intranasal vaccination following a single subcutaneous vaccination produced more effective immunity than one subcutaneous dose alone. Thus a vaccination regime was established which protected calves against experimental challenge and which could thefore be used in the field to assess the role of Pi3 virus in calf respiratory disease.

Administration, Intranasal↗
PubMed1977

Interactions between calf alveolar macrophages and parainfluenza-3 virus.

Cells washed from the lungs of freshly killed calves (lung wash cells; LWC) were cytotoxic for calf kidney (CK) target cells infected with parainfluenzavirus type 3 (Pi-3) when assayed by chromium release. LWC collected from 25 calves, including two gnotobiotic animals that had not previously been infected with Pi-3, were all cytotoxic, giving a specific chromium release between 11 and 50%. Cytotoxicity was detected at ratios of LWC to target cell as low as 5:1. The cytotoxic reaction required viable LWC, was inhibited by Pi-3 antiserum, and was not the result of virus-induced damage to the target cells. The cytotoxic cells in the LWC population were identified as alveolar macrophages from observations on glass adherence, phagocytic activity, killing by silica and fine-structural appearance. When LWC were added to CK cells or organ cultures of bovine trachea infected with Pi-3, the yield of virus was reduced for the first 2 to 3 days. However, subsequently, Pi-3 virus replicated in the LWC. Infection of LWC with Pi-3 virus reduced their cytotoxic activity. The significance of these interactions between alveolar macrophages and Pi-3 virus is discussed.

Animals↗
PubMed1976

The growth of respiratory syncytial virus in organ cultures of bovine foetal trachea.

Respiratory syncytial (RS) virus grown in organ cultures of bovine foetal trachea at 37 degrees C and pH 7.2 reached maximum titres of up to 1 X 10(5) PFU/ml between 11 and 21 days after inoculation. Virus yield was increased three fold by incubation at 33 degrees C, but depressed by the addition of RS virus antiserum, with or without bovine complement, or by the addition of alveolar macrophages. Variation in pH or the concentration of foetal calf serum and magnesium chloride did not affect the virus yield. Virus growth did not affect ciliary activity of the cultures. Histological changes involved slight flattening of the epithelium and the appearance of phloxinophilic inclusion bodies. Fluorescent antibody staining showed more virus antigen in the peri-tracheal connective tissue than in the ciliated epithelium. The presence of non-cytopathic mucosal disease (MD) virus in RS virus infected organ cultures slightly depressed RS virus growth but did not influence ciliary activity. These in vitro experiments suggest that the tracheal epithelium may not be an important target in the pathogenesis of RS virus infection in vivo.

Animals↗
PubMed1976

Experimentally produced calf pneumonia.

Experimental pneumonia was produced in calves by the endobronchial inoculation of pneumonic lung homogenates. Irradiated homogenates produced minimal pneumonia. Ampicillin treatment of the homogenates and the experimental calves reduced the extent of pneumonia. Treatment with tylosin tartrate prevented experimental pneumonia. These results suggest that the total pneumonia was due to organisms susceptible to tylosin tartrate and that the residual pneumonia remaining after ampicillin treatment was due to organisms susceptible to tylosin tartrate but not to ampicillin. Of the organisms isolated from the lungs, the ones in this latter category most likely to be responsible are Mycoplasma dispar and ureaplasmas (T-mycoplasmas).

Acholeplasma laidlawii↗
PubMed1976

Induction of pneumonia in gnotobiotic calves following inoculation of Mycoplasma dispar and ureaplasmas (T-mycoplasmas).

Cloned cultures of Mycoplasma dispar and of Ureaplasma sp were inoculated endobronchially into gnotobiotic calves. The resulting pneumonia was estimated to involve 2 to 10 per cent of the lung although no clinical signs were observed. The histopathological lesions consisted of infiltration with mononuclear cells, cuffing (peribronchiolar lympho-reticular hyperplasia), catarrhal bronchiolitis and atelectasis. The results indicate that both M dispar and Ureaplasma sp are capable of causing sub-clinical cuffing pneumonia in calves.

Animals↗
PubMed1975

Quantitative studies on bovine immunoglobulins.

The influence of serum immunoglobulins on the incidence of calf pneumonia, and the relationship between sub-clinical pneumonia, and calf serum Ig levels, is discussed. Monospecific antisera were used to measure levels of IgG1, IgG2, IgM and IgA in the sera of bull calves aged around 2 1/2 weeks. These calves were selected retrospectively according to their disease record up to six months of age. A clear association was found between low levels of IgG1, IgG2 and IgA in the "2 1/2-week" sample and subsequent susceptibility to pneumonia at around 2 1/2 months of age. Calves showing signs of pneumonia had low levels of IgG1 (45-5 per cent had less than 8 mg per ml compared with "now-pneumonic" calves which had relatively high levels (only 9.5 per cent had less than 8 mg per ml). In contrast, older calves bled at monthly intervals and found to have pneumonic lesions at slaughter had significantly evevated levels of both IgGa and IgG2.

Age Factors↗
PubMed1975

Mortality from arteriosclerotic disease and consumption of hydrogenated oils and fats.

Consumptions of chemically modified hydrogenated fat are estimated for the United Kingdom standard regions, conurbations, and urban/rural aggregates as well as for the social classes. Consumptions are shown to correlate satisfactorily with mortality from arteriosclerotic disease and account reasonably well for certain peculiarities in the ratio of female to male death rates and for secular changes in mortality patterns.

Adult↗