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Biomedical subjects

J W Tyler

Publications and source records attributed to J W Tyler.

At least 127 records · Page 7Linked to original sources
PubMed1989

Ontogeny of the third component of complement in neonatal swine.

Ontogeny of the third component of complement (C3) was monitored in 10 neonatal swine, using a radial immunodiffusion technique. Significant differences in mean serum C3 concentrations, expressed as percentage of C3 concentration in a pooled standard drawn from 15 adult swine, were not observed between serum samples collected before pigs suckled and at 2 days of age (P = 0.2583). Serum C3 concentrations increased significantly between 2 and 7 days of age (P less than 0.0001) and 7 and 14 days of age (P less than 0.0001). Concentrations comparable with those in adults were observed at 14 days of age and significant changes were not observed thereafter. Acquisition of adult concentrations of C3 appeared to be a function of endogenous production by the neonate, rather than by passive colostral transfer.

Animals↗
PubMed1989

Rapid decay of serum IgG recognizing gram-negative cell wall core antigens in neonatal calves.

Serum immunoglobulins of the IgG isotype recognizing common gram-negative cell core epitopes were serially measured, using a direct ELISA, on samples obtained from 20 neonatal Holstein calves. An R-mutant Escherichia coli (strain J5) was used as a plate antigen in this assay. Total serum IgG concentration was measured using radial immunodiffusion. Half-lives of core antigen-specific IgG (7.56 days) and total serum IgG (22.66 days) were dramatically different (P less than 0.0005). This may be an indication of cross-reactive consumption of core antigen-specific immunoglobulins.

Animals↗
PubMed1989

Relationship between test-day measures of somatic cell count and milk production in California dairy cows.

The relationship between test-day measures of milk somatic cell count and milk yield was evaluated using the November 1985 test data from 8352 Holstein cattle (2923 primiparous and 5429 multiparous cows) located in ten Tulare County, California dairies. Following correction for herd and stage of lactation effects, design variable regression was used to create separate models for primiparous and multiparous cows predicting the changes in milk production associated with milk somatic cell count class. Cell counts were stratified by 1/2 loge cell count (x1000 cells/mL) units, permitting comparisons with previous studies. Cell counts less than 148,000/mL were not found to be associated with significant reductions in milk yield when compared to the reference class (cell counts less than 20,000/mL). Consistent incremental decreases in milk production were not noted with increasing cell count strata, even following the natural log transformation. The most dramatic production losses were noted in the range of 148,000 to 665,000 cells/mL. Primiparous cattle in the 403,000 to 665,000 cell count strata experienced a 5.22 kg (19.72%) decrease in test-day milk yield. Multiparous cattle in the same class experienced 3.01 kg (7.82%) reductions in milk production. Primiparous and multiparous cows had similar production losses. The study population differed from previous studies on the basis of herd size, milk production and the level of udder health, measured by milk somatic cell count. These differences and the choice of experimental design may in part explain differences in study results and conclusions.

Animals↗
PubMed1989

Humoral recognition of lipopolysaccharide core antigens of gram-negative bacteria in neonatal swine.

Serologic recognition of common lipopolysaccharide core antigens has been related to enhanced resistance to gram-negative bacterial disease in several species. Class-specific titers (IgG, IgM) were determined by direct ELISA, using intact Escherichia coli (J5) as a plate antigen. Serum samples were obtained from 224 neonatal swine between the ages of 36 and 60 hours. The mean (+/- SEM) log10 IgG titer against gram-negative core antigens was 1:1,713 +/- 0.4718 and the mean log10 IgM titer was 1:202 +/- 0.5644. The IgG titer was directly related with litter size, birth weight, and serum total IgG concentration; IgM titer was directly related with dam parity and serum total IgG concentration.

Animals↗
PubMed1988

The biosynthetic implications of acetate and glutamate incorporation into (3R,5R)-carbapenam-3-carboxylic acid and (5R)-carbapen-2-em-3-carboxylic acid by Serratia sp.

Two new beta-lactams have been isolated from strains of Serratia and Erwinia sp. and identified as (3R,5R)- and (3S,5R)-carbapenam-3-carboxylic acid. These novel carbapenams lack antibacterial activity, are resistant to both beta-lactamases I and II from Bacillus cereus and are not detected by the lactamase induction assay. Radiolabelled and stable isotope experiments have established that both metabolites together with the antibiotic 5R-carbapenem-3-carboxylic acid are glutamate and acetate derived. A number of possible pathways for the biosynthesis of these compounds as well as their relationship to the more complex members of the carbapenem family of beta-lactam antibiotics are discussed.

Acetates↗
PubMed1988

Relationship between serologic recognition of Escherichia coli 0111:B4 (J5) and clinical coliform mastitis in cattle.

Serum IgG1 ELISA titers recognizing gram-negative core antigens (Escherichia coli [J5]) were studied at a large dairy in central California. Population mean log10 titer was 2.7357 (equivalent to 1:544) with a SE of 0.03843. Titers increased with increased lactation number (unstandardized regression coefficient = 0.06733). Changes in lactation number accounted for only 6.77% of titer variation. Titers less than 1:240 were associated with 5.33 times the risk of clinical coliform mastitis. Also, older cattle were at greater risk to develop clinical coliform mastitis. These factors apparently affect incidence in a nonlinear fashion, with greatly increased risk associated with titers less than 1:240 and with fourth or greater lactations.

Age Factors↗
PubMed1988

Age-related variations in serum concentrations of the third component of complement in swine.

Single radial immunodiffusion was used to determine the concentration of the third component of complement (C3) in serum from swine in the following age groups; 36 to 60 hours (neonates), 6 to 7 weeks (weanlings), 4 to 5 months (adolescents) and greater than 1 year (adults). Mean serum C3 concentrations, expressed as the percentage of pooled reference sera from 15 adult swine for the 4 groups were 23, 123, 119, and 98%. With the exception of mean values for weanlings and adolescents, all comparisons of group means were significantly different. Regression models were developed to estimate serum C3 concentration in neonates as a function of litter size, birth weight, and total serum IgG concentration. Increases in birth weight and litter size were accompanied by increased serum C3 concentration, possibly reflecting ontogenic variation of the complement system at the end of gestation. Passive transfer of colostral immunoglobulins, as measured by total serum IgG concentration, was inversely related to serum C3 concentration in neonatal swine, suggesting that colostral absorption of C3 has minimal impact on complement activity in neonatal swine.

Aging↗
PubMed1986

The lethal "cot-death syndrome" fallacy.

The ammonia factor theory of infant death causation shows how the known, deadly properties of this respiratory poison, potentially present at every infant's cot, are compatible with the known causative relationships found with "cot-death syndrome" infants. It also predicted and demonstrated that a causal relationship existed between cot-death infants and most other post neo-natal infant deaths. The ammonia factor theory is quite incompatible with the medical profession's "cot-death syndrome" model. A critical evaluation of the medical profession's "cot-death syndrome" model shows that it provides no predictive, causative, diagnostic, or preventative dimensions and is used by some of the medical profession as a tool of fear to extract research monies and by others in the profession to placate parents. The "cot-death syndrome" model is a definition of a non-reality and the antithesis of a scientific model. As a mathematical model it is impossible and is supported by statistical gerrymandering. It places diagnosed "cot-death syndrome" parents in legal jeopardy. Its correlation with the reality of infant death is staggeringly improbable. These features are in stark contrast with the ammonia factor theory of infant death causation. The ammonia factor theory shows that the overall infant death rate is preventable through a programme of welfare, as well as through educational, social and environmental improvements. The medically centred "cot-death syndrome" model is a useless, lethal fallacy. It is politically obstructive. It must be discarded.

Ammonia↗
PubMed1985

Cot-death: the ammonia factor.

Wet nappies at night could cause infants at risk to die. Tyler first suspected this ten years ago when his head was jerked back from his infant son's cot by the pungent odour of ammonia gas. This theory is consistent with the full epidemiology of cot-death. Ammonia is an insidious poison which has a wide and varied range of effects on the respiratory and nervous systems according to concentration and length of exposure. At its mildest it irritates the tissues. In larger doses ammonia can cause pulmonary oedema and pneumonitis. It can also cause stenosis of affected organs. Its chief danger lies in its potential to disrupt oxygenation at every level throughout the body. Acute and chronic poisoning profiles indicate the possibility that numbers of infants reported as dying from gastro-intestinal or respiratory disease could have been ammonia poisoning victims. Predisposing factors, such as smoking during pregnancy, are shown to contribute to the vulnerability of the infant to ammonia poisoning. The theory provides the framework for the development of an effective programme of infant death prevention.

Ammonia↗
PubMed1984

Segmental motion in pseudomonic acid A: a carbon-13 spin-lattice relaxation time study at two field strengths.

The mobility of pseudomonic acid A in dimethyl sulfoxide-d6 solution has been determined from 13C spin-lattice relaxation time measurements at two field strengths. The central tetrahydropyran ring reorientates isotropically with a rotational correlation time of approximately 280 picoseconds/ radian . Both side-chains exhibit marked segmental motion with correlation times decreasing to only approximately 50 picoseconds/ radian at the end of the nonanoic acid side-chain.

Anti-Bacterial Agents↗
PubMedDate not supplied

Facial fibrosarcoma in two cows.

Fibrosarcoma is a common tumor affecting bone, but is uncommon in cows. Reported here are two bovine cases of facial fibrosarcoma that were very invasive.

Animals↗
PubMedDate not supplied

Immunity targeting common core antigens of gram-negative bacteria.

Antibodies against common gram-negative core antigens can provide protection against environmental, commensual, and contagious bacteria that cause life-threatening gram-negative sepsis/endotoxemia. Cross-protective immunity may be effective against many common livestock diseases, including neonatal coliform septicemia, coliform mastitis, septic metritis, and severe enteritis. The greatest potential benefit of cross-protective immunity may be realized in the reduction of ill-thrift and mortality of neonates. The use of active and passive immunization against core antigens common to gram-negative bacteria has been successful in human beings, laboratory animals, and livestock. Protection has been observed following challenge with either heterologous endotoxin or unrelated, live, virulent gram-negative bacteria.

Animals↗
PubMedDate not supplied

Pulmonary hypertension and cardiac insufficiency in three cows with primary lung disease.

Increased pulmonary arterial pressures as a result of pulmonary disease are described in two cows with chronic pneumonia and one cow with acute pneumonia. Based on clinical signs of congestive right heart failure, increased pulmonary arterial pressure, and right ventricular hypertrophy, cor pulmonale was diagnosed in one cow. Two cows had increased pulmonary arterial pressure and signs of right heart insufficiency, but right ventricular hypertrophy was not identified. Two of the cows had ventral edema and exercise intolerance. All cows had jugular venous distention and increased right atrial and pulmonary arterial pressures. Peripheral arterial PaO2 was decreased in two cows, and not measured in the third cow. Although an uncommon cause of congestive heart failure in cattle at low altitudes, pulmonary hypertension should be considered in cattle with clinical right heart failure.

Animals↗
PubMedDate not supplied

Cerebrospinal fluid composition of cattle with endotoxin-induced mastitis treated with isotonic (0.9%) or hypertonic (7.5%) sodium chloride.

This study examined the safety of intravenous hypertonic saline in cattle with experimental gram-negative endotoxemia. Cerebrospinal fluid (CSF) composition was examined in five control cows and eight treated cows 24 hours after the intramammary infusion of 1 mg of endotoxin. Four of the endotoxin challenged cows were treated intravenously with isotonic (0.9%) sodium chloride and four cows were treated intravenously with hypertonic (7.5%) sodium chloride. Decreased CSF osmolality, and sodium and alpha globulin concentrations and increased CSF concentrations of beta globulin were observed in both endotoxin-challenged saline-treated groups. No CSF compositional differences were observed between endotoxin-challenged cows receiving isotonic or hypertonic saline. Although no cytologic or biochemical evidence of salt poisoning was observed in cows receiving hypertonic saline, significant changes were observed in the CSF composition of both endotoxin-infused saline-treated groups.

Animals↗
PubMedDate not supplied

Evaluation of a whole blood glutaraldehyde coagulation test for the detection of failure of passive transfer in calves.

The accuracy of a commercially available whole blood glutaraldehyde clot test in the detection of failure of passive transfer (serum immunoglobulin [Ig]G1 < 1,000 mg/dL) in neonatal calves was evaluated. Serum samples were obtained from 242 calves ranging in age from 1 to 8 days, and comparisons were made with serum IgG1 concentrations determined by radial immunodiffusion. Both the sensitivity and specificity of the currently marketed whole blood glutaraldehyde clot test are inadequate for routine diagnostic use. Concerns regarding test sensitivity are the most problematic. Sensitivity varied from 0.41 to 0.00, depending on the choice of test endpoint. Specificity varied from 0.85 to 1.00, depending on the choice of test endpoint. Regression analysis demonstrated that the relationship between serum IgG1 concentration and the glutaraldehyde clot results, although significant (P < .10), was of negligible biological relevance (r2 = .034).

Animals↗