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Biomedical subjects

C L Meyer

Publications and source records attributed to C L Meyer.

16 recordsLinked to original sources
PubMed2001

Phenotypic trends in incidence of stillbirth for Holsteins in the United States.

The objectives for this study were to determine 1) if there was a trend in stillbirths for the U.S. Holstein population, 2) if stillbirths are the same trait in primiparous and multiparous cows, and 3) what was the role of dystocia in stillbirths. A sample of 666,341 births from the MidStates Dairy Records Processing Center and the National Association of Animal Breeders was used to examine the influence of sire, herd, year, season, sex of calf, parity of dam, calving ease, and gestation length on the survival of the calf. Parity was scored as an ordered variable (1, 2, 3+). Calving ease was scored on a scale of 1 (no assistance) to 3+ (needed assistance). An increasing trend in stillbirths was found in primiparous and multiparous cows. The percentage of stillborn calves in primiparous cows increased from 9.5 in 1985 to 13.2 in 1996. Stillbirths in multiparous cows increased from 5.0 to 6.6% from 1985 to 1996. Variation about the trend was greater in primiparous cows than in multiparous cows. Dystocia was a major determinant of stillbirth incidence, but the association was stronger in primiparous cows. Sex of calf had different associations with stillbirth incidence in primiparous and multiparous cows. Gestation length and season of birth also had significant associations with stillbirth incidence. Logistic regression models with fixed and random effects were fit to the data to preserve the binary nature of the stillbirth response. The expected probability of stillbirths for an average herd and sire was 10% for primiparous cows and 5% for multiparous cows. Replacement of stillborn calves is a substantial cost to the dairy industry at more than $125.3 million per year. Because of the increasing incidence of stillbirths, these costs have increased by $75.9 million from 1985 to 1996.

Animals↗
PubMed2001

Genetic evaluation of Holstein sires and maternal grandsires in the United States for perinatal survival.

Stillbirth, defined as a calf that dies just prior to, during, or within 48 h of parturition, represents a reoccurring concern among breeders of dairy cattle in the United States. About 11% of parturitions of primiparous Holstein cows result in the death of a calf; 5.7% in multiparous cows. Genetic evaluations can be reported as perinatal survival to 48 h to emphasize the positive information about the trait. The purpose of this research was to: 1) estimate genetic parameters by restricted maximum likelihood for perinatal survival rates; 2) characterize the genetic evaluation of sires for the perinatal survival of their progeny and maternal grandsires for the perinatal survival of their daughters progeny; and 3) estimate genetic trends from 1984 to 1994. Data (n = 666,339) were from the National Association of Animal Breeders calving ease database. Over 600 new young sires were available each year. The binomial response variable, 1 = alive, 0 = stillborn within 48 h of parturition was analyzed by using a sire-maternal grandsire linear mixed model. The model included fixed effects for sex of calf, dystocia, and season of birth, and gestation length as a covariate; correlated random effects of sire and maternal grandsire; and uncorrelated random effects of herd-years. Parturitions of primiparous and multiparous cows were analyzed separately. In primiparous cows, heritability estimates were 1.1 and 2.2% for sire of the calf and maternal grandsire, respectively. The genetic correlation between sire and maternal grandsire predicted transmitting ability (PTA) for perinatal survival, was 0.31; simple product moment correlations among sire-MGS PTA were 0.43 and 0.46 for primiparous and multiparous cows, respectively. The PTA for sire of the calf ranged from -2.9 (lower survival) to 2.8% (higher survival). Mean PTA from 1984 to 1994 was quite variable from year to year. Evidence showed a slightly negative, but nonsignificant, genetic trend in perinatal survival (-0.04% per year for sires and -0.02% per year for maternal grandsires). Estimates of genetic parameters and genetic trends for data from multiparous cows are also reported. Correlations among PTA for perinatal survival, milk yield, and calving ease are given.

Animals↗
PubMed2000

Interactions among factors affecting stillbirths in Holstein cattle in the United States.

Each year about 7% of the Holstein calves born in the United States die within 48 h of birth. The exact cause of death is unknown. The purpose of this article is to examine the complex interactions among factors (e.g., parity, season of birth, dystocia, year) contributing to stillbirth rates. A modified chi-squared automated interaction detection algorithm was used to develop classification trees explaining the most likely sequence of factors that result in a stillborn calf. The data were 666,341 births from the MidStates Dairy Records Processing Center and the National Association of Animal Breeders. Primiparous and multiparous cows clearly differ in the rate of stillbirths, 11.0 and 5.7%, respectively. Dystocia followed parity as the next most important factor within both primiparous and multiparous cows. In primiparous cows, season, year of birth, or gestation length ranked third as an important predictor for dystocia equal to 1, 2, or 3+, respectively. Gestation length ranked third in importance among the factors that affect stillbirth rates for all levels of dystocia in multiparous cows. Among multiparous cows needing assistance (dystocia 3+), stillbirth rates were greatest for shorter gestations less than the average of 280 d, 55.3% for -15 to -12 d, 45.5% for -11 to -9 d, 33.7% for -8 to -5 d, 23.8% for -4 to 13 d, and 35.4% for 14 to 15 d. Gestation length pinpointed the time when stillbirths occurred, as indicated by the increase from 23.8% stillbirth rate among calves born at or above the mean gestation length to 55.3% for those calves born -15 to -12 d below the mean gestation. Further investigation of the relationship between stillbirth rates and gestation length is needed to develop a more complete understanding of the biological processes resulting in the loss of calves at birth.

Algorithms↗
PubMed1994

Characteristics of participants in water exercise programs compared to patients seen in a rheumatic disease clinic.

PURPOSE: To determine if community-based water exercise programs are serving people with significant levels of disability and pain. METHODS: Eighty-seven participants in water exercise classes and 174 patients from a rheumatic disease clinic were matched for age, sex, and diagnosis and comparisons were made between the groups for the study variables. RESULTS: Patients had significantly higher disability, pain, global disease severity, anxiety, and depression and lower grip strength than participants. Osteoarthritis (OA) patients (n = 126) compared to OA participants (n = 63) had similar significant differences for all variables. Rheumatoid arthritis (RA) patients' (n = 48) scores were all more severe than RA participants' scores (n = 24), and these differences were similar in magnitude to OA differences, but only global disease severity and grip strength were statistically significantly different. CONCLUSIONS: Water exercise classes are reaching persons with important levels of dysfunction and pain, but more severely affected patients are underrepresented in such programs.

Activities of Daily Living↗
PubMed1991

Comparison of six ECMO selection criteria and analysis of factors influencing their accuracy.

This study compared six extracorporeal membrane oxygenation (ECMO) selection criteria in 42 neonates and analyzed factors influencing the accuracy of outcome predictions. The sensitivity of the criteria in identifying fatal cases varied from 0.44 to 0.94 and the specificity of predictions of survival ranged from 0.42 to 0.69. The criterion having the highest sensitivity had the lowest specificity and conversely the criterion with the lowest sensitivity had the highest specificity. Overall accuracy of the criteria, as measured by the total number of correct outcome predictions, differed little among the criteria (23/42 to 27/42 correct predictions). Three factors influenced predictive accuracy: 1) a primary diagnosis of congenital diaphragmatic hernia (CDH) was associated with a greater mortality (P less than 0.001) and a significantly higher positive predictive value (PPV) for all criteria (P = 0.0009-0.012) than that seen in patients with other primary diagnoses; 2) calculating the alveolar-arterial oxygen gradient using an assumed, rather than measured barometric pressure, or estimating oxygenation index using a calculated, rather than a measured, mean airway pressure, increased false positive mortality predictions in non-CDH patients; and 3) requiring a peak inspiratory pressure (PIP) of at least 50 cm H2O in the definition of maximal medical management, rather than a PIP of 20-49 cm H2O, significantly increased the PPV for three of four criteria examined (P = 0.02-0.04). Awareness of these factors may facilitate the identification of neonates who need ECMO to survive.

Contraindications↗
PubMed1991

Spontaneous, isolated intestinal perforations in neonates with birth weight less than 1,000 g not associated with necrotizing enterocolitis.

From January 1986 through December 1988, we have seen 7 cases of isolated intestinal perforation in 250 infants with birth weights less than 1,000 g (3% incidence) without histological or clinical evidence of necrotizing enterocolitis (NEC). Patients had a mean birth weight of 670 g, gestational age of 25.1 weeks, and sustained a perforation at a chronological age of 10.4 days. No infants had been fed. A definite, blue-discolored abdomen was the only consistent clinical sign (n = 7). Free intraperitoneal air on radiograms was rarely observed (n = 1). Abdominal ultrasounds (n = 3) and metrizamide contrast studies (n = 3) were not diagnostic. The presence of an umbilical artery catheter (7/7), falling hematocrit (6/7), thrombocytopenia (5/7), and a positive diagnostic paracentesis were most commonly found. In 6 of 7 patients, this perforation was associated with coagulase-negative staphylococcal sepsis. Surgical or histological diagnosis showed focal perforation in either the terminal ileum (n = 4) or the transverse and descending colon (n = 3). Survival was 3 of 7; 2 patients died of intracranial hemorrhage and 2 died of Candida sepsis. We conclude that (1) intestinal perforation can occur in the absence of NEC; (2) bluish discoloration of the abdomen is the most reliable clinical finding; and (3) perforation may be associated with coagulase-negative staphylococcal infection.

Colonic Diseases↗
PubMed1987

Apparent affinity values of beta-adrenergic blockers in a tissue with a mixture of beta-adrenergic receptor subtypes.

The affinity (pA2 or pKB) values of 3 different beta-adrenoceptor blocking drugs were determined using the isolated guinea-pig tracheal chain preparation. The pA2 values for each of the beta-adrenoceptor blocking drugs were determined, using respectively isoprenaline and salbutamol as agonists. Neuronal and extraneuronal uptake of agonist were blocked with phenoxybenzamine. With isoprenaline, a nonselective beta-adrenoceptor agonist, the pA2 values for the blocking drugs were unacceptable. Using the beta 2-selective beta-adrenoceptor agonist, salbutamol, under the same conditions, resulted in consistent pA2 values for the nonselective beta-adrenoceptor blocking drug propranolol and some concentrations of the beta 2-selective blocking drug ICI 118.551. pA2 Values for the beta1-selective antagonist atenolol were not consistent for the concentrations used. It is suggested that this is due to the guinea-pig trachea having a mixed beta-adrenoceptor population. A mathematical model is presented that shows the influence of a mixed receptor subpopulation on the shift of theoretical agonist concentration-effect curves in the presence of a competitive antagonist. It can be shown that the affinity values of antagonists for a specific receptor subtype are to a greater or lesser degree unreliable, depending upon the selectivity-ratios of both the agonist and the antagonist used.

Adrenergic beta-Antagonists↗
PubMed1983

Legionella pneumonia in guinea pigs exposed to aerosols of concentrated potable water from a hospital with nosocomial Legionnaires' disease.

An investigation of an outbreak of nosocomial legionella pneumonia revealed that the potable water of the hospital was contaminated with a distinctive strain of Legionella pneumophila (designated the Le-1 strain), which was by culture and serology linked with human illness. To examine the possible role of this water in this outbreak, eight healthy guinea pigs were exposed to an aerosol of concentrated potable water. Seven animals developed pneumonia due to the Le-1 strain of L. pneumophila. In one of these guinea pigs, the Le-1 strain was also isolated from the blood and spleen. These results provide support to the theory that exposure of humans to aerosols of potable water contaminated with L. pneumophila may cause legionella pneumonia.

Aerosols↗
PubMed1982

Evaluation of a system for continuous neonatal blood pressure monitoring.

The purpose of this study was to determine the effects of varying infusion rates as well as different catheter sizes and types on the mean arterial pressure as measured by a system in which the pressure transducer is connected in series to the line of fluids being administered through the catheter. The results of this study show that, under most circumstances, errors in mean blood pressure measured by this system are minimal and clinically insignificant.

Blood Pressure Determination↗
PubMed1981

Should linen in newborn intensive care units be autoclaved?

The American Academy of Pediatrics' Standards and Recommendations for Hospital Care of Newborn Infants recommends that linen in newborn intensive care, intermediate care, continuing care and admission observation areas be autoclaved. Questionnaires sent to 269 directors of newborn intensive care units (69% returned) showed that 74% of the respondents do not autoclave linen used in their newborn intensive care unit. There were 284 linen cultures performed in our newborn intensive care unit where linen is not autoclaved; 68% of the cultures were positive, but only 2.5% had a colony count greater than 20 colonies per plate. The most common organisms obtained were Staphylococcus epidermidis, diphtheroids, and Micrococcus species. Two cultures grew Staphylococcus aureus, one colony and two colonies per plate. Three-factor analysis of variance showed that the location of the linen in the top of the pile exerted a statistically significant effect on the bacterial contamination rate. The fact that three fourths of neonatal intensive care centers in this country do not autoclave nursery linen, the lack of reports in the literature relating linen contamination to nosocomial infections, and the microbiologic results of this study suggest that the recommendations of the American Academy of Pediatrics merit further study and reevaluation.

Bedding and Linens↗
PubMed1979

Neonatal seizures.

Explore the source record for details and available documents.

Diagnosis, Differential↗
PubMedDate not supplied

Comparison of pressure-volume-flow relationships in centrifugal and roller pump extracorporeal membrane oxygenation systems for neonates.

Theoretical advantages and risks exist for the use of both the centrifugal and roller pump systems in neonatal extracorporeal membrane oxygenation (ECMO). The authors studied the pressure-volume-flow relationships in clinically configured ECMO systems using these two pumps and a simulated patient to characterize differences in the circuit mechanics of the two systems, and thereby improve the design of subsequent clinical comparative trials of the pumps themselves. The relationship between flow and pressure generated across the pump was identical for the two systems. Within the range of clinically used flows, there was a direct relationship between pump revolution and flow with the roller pump, and between pump revolution and pressure generated for the centrifugal pump. Flow was limited in both systems by restrictions on negative pressure generating capacity. In the roller pump circuit, the venous reservoir (bladder box) assembly interrupted flow when negative pressure exceeded -20 mmHg; in the centrifugal pump system, forward flow stopped when negative pressure exceeded -100 mmHg. Volume had no detectable effect on the patient-pump inlet pressure gradient until critically low volumes were reached. At that point, removal of a few milliliters of volume led to large increases in the pressure gradient. The authors conclude that differences in pressure-volume-flow relationships between roller and centrifugal pump ECMO systems are due to the presence of the bladder box in the roller pump circuit. The advantages and disadvantages of the greater negative pressure in the centrifugal pump system require further study.

Equipment Design↗