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Biomedical subjects

W R Butler

Publications and source records attributed to W R Butler.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effect of dietary lipid source on conjugated linoleic acid concentrations in milk fat.

Conjugated linoleic acids (CLA) found in ruminant milk fat are a byproduct of incomplete biohydrogenation of lipids by ruminal bacteria. We examined the effect of different dietary fat supplements and processing methods on CLA. In trial 1, dietary supplements of Ca salts of fatty acids from canola oil, soybean oil, and linseed oil increased CLA content of milk fat by three- to fivefold over the control diet. Trials 2 and 3 examined the effect of processing methods for heat treatment of full fat soybeans. In trial 2, extrusion, micronizing, and roasting resulted in two- to threefold greater concentrations of CLA in milk fat than the control diet (raw ground soybeans). In trial 3, different temperatures of extrusion (120, 130, and 140 degrees C) increased the CLA content of milk fat to a similar extent; CLA averaged 19.9 mg/g of fatty acids for the extrusion treatments compared with 4.2 mg/g of fatty acids for the control diet (raw ground soybeans). Fish oil (200 and 400 ml/d) was examined in trial 4 and both levels resulted in CLA concentrations in milk fat that were about threefold greater than the control diet. In trial 5, grain and silage from a high oil corn hybrid increased the CLA content of milk fat; however, responses were modest with the CLA concentration (mg/g of fatty acids) averaging 4.6 and 2.8 for diets with high oil hybrid and normal hybrid, respectively. Similarly, dietary supplements of animal fat byproducts (tallow plus yellow grease; trial 6) resulted in modest increases in the CLA content of milk fat. Overall, several dietary manipulations involving lipid sources and processing methods were identified that allow for a marked increase in the conjugated linoleic acid content of milk fat.

Animal Feed↗
PubMed2000

Nutritional interactions with reproductive performance in dairy cattle.

Increased capability for milk production has been associated with a decline in fertility of lactating cows. Nutritional requirements increase rapidly with milk production after calving and result in negative energy balance (NEBAL). NEBAL delays the time of first ovulation through inhibition of LH pulse frequency and low levels of blood glucose, insulin and insulin-like growth factor-I (IGF-I) that collectively restrain estrogen production by dominant follicles. Up-regulation of LH pulses and peripheral IGF-I in association with the NEBAL nadir facilitates ovulation. NEBAL reduces serum progesterone concentrations and fertility. Diets high in crude protein support high milk yield, but are also associated with lower reproductive performance. High protein can result in elevated plasma urea concentrations that affect the uterine environment and fertility. Nutritional interactions resulting in poor fertility of high producing dairy cows include the antecedent effects of NEBAL and effects of high dietary protein.

Animal Nutritional Physiological Phenomena↗
PubMed2000

Mycobacterium kubicae sp. nov., a slowly growing, scotochromogenic Mycobacterium.

A previously uncharacterized, slowly growing, scotochromogenic Mycobacterium species was detected by HPLC analysis of the cell-wall-bound mycolic acids. The mycolic acid pattern standard was shown to be a late-eluting, contiguous peak cluster occurring at approximately 8-9 min. The mycolic acid pattern was noted to be most similar in number of peaks and range of elution to that reported previously for Mycobacterium asiaticum. However, the relative distribution of peaks within the elution range demonstrated a pattern with prominent peaks that started to emerge later than the characteristic M. asiaticum pattern. Standard biochemical identification test results were similar to those of the photochromogenic species M. asiaticum. Comparative 16S rRNA gene sequence analysis confirmed the genetic uniqueness of the strains and demonstrated the unclassified mycobacteria to be in a unique, intermediate position between slow and rapid growers in the phylogenetic tree of Mycobacterium. The name Mycobacterium kubicae sp. nov. is proposed for this taxon. The type strain is CDC 941078T (= ATCC 700732T = CIP 106428T).

Base Sequence↗
PubMed2000

Phenotypic characterization of pncA mutants of Mycobacterium tuberculosis.

We examined the correlation of mutations in the pyrazinamidase (PZase) gene (pncA) with the pyrazinamide (PZA) resistance phenotype with 60 Mycobacterium tuberculosis isolates. PZase activity was determined by the method of Wayne (L. G. Wayne, Am. Rev. Respir. Dis. 109:147-151, 1974), and the entire pncA nucleotide sequence, including the 74 bp upstream of the start codon, was determined. PZA susceptibility testing was performed by the method of proportions on modified Middlebrook and Cohn 7H10 medium. The PZA MICs were > or =100 microg/ml for 37 isolates, 34 of which had alterations in the pncA gene. These mutations included missense substitutions for 24 isolates, nonsense substitutions for 3 isolates, frameshifts by deletion for 4 isolates, a three-codon insertion for 1 isolate, and putative regulatory mutations for 2 isolates. Among 21 isolates for which PZA MICs were <100 microg/ml, 3 had the same mutation (Thr47-->Ala) and 18 had the wild-type sequence. For the three Thr47-->Ala mutants PZA MICs were 12.5 microg/ml by the method of proportions on 7H10 agar; two of these were resistant to 100 microg of PZA per ml and the third was resistant to 800 microg of PZA per ml by the BACTEC method. In all, 30 different pncA mutations were found among the 37 pncA mutants. No PZase activity was detected in 35 of 37 strains that were resistant to > or =100 microg of PZA per ml or in 34 of 37 pncA mutants. Reduced PZase activity was found in the three mutants with the Thr47-->Ala mutation. This study demonstrates that mutations in the pncA gene may serve as a reliable indicator of resistance to > or =100 microg of PZA per ml.

Amidohydrolases↗
PubMed1999

Identification of Mycobacterium species by PCR-restriction fragment length polymorphism analyses using fluorescence capillary electrophoresis.

We developed a scheme for the rapid identification of Mycobacterium species based upon PCR amplification of polymorphic genetic regions with fluorescent primers followed by restriction and analysis by fluorescence capillary electrophoresis. Mycobacterium species were identified by restriction enzyme analysis of a 439-bp segment of the 65-kDa heat shock protein gene (labeled [both strands] at the 5' end with 4,7,2',7'-tetrachloro-6-carboxyfluorescein) using HaeIII and BstEII and of a 475-bp hypervariable region of the 16S rRNA gene (labeled [both strands] at the 5' end with 6-carboxyfluorescein) using HaeIII and CfoI. Samples were analyzed on an automated fluorescence capillary electrophoresis instrument, and labeled fragments were sized by comparison with an internal standard. DNA templates were prepared with pure cultures of type strains. In all, we analyzed 180 strains, representing 22 Mycobacterium species, and obtained distinctive restriction fragment length polymorphism (RFLP) patterns for 19 species. Three members of the Mycobacterium tuberculosis complex had a common RFLP pattern. A computerized algorithm which eliminates subjectivity from pattern interpretation and which is capable of identifying the species within a sample was developed. The convenience and short preparatory time of this assay make it comparable to conventional methodologies such as high-performance liquid chromatography and hybridization assays for identification of mycobacteria.

Bacterial Proteins↗
PubMed1999

Effects of energy balance on follicular development and first ovulation in postpartum dairy cows.

As milk production has increased during the past four decades, conception rates in lactating cows have declined. Although reduced reproductive performance has been associated with high milk yields, measures of postpartum ovarian activity have been more closely related to energy balance. The relationship between daily energy balance and postpartum reproductive activity is confirmed by longer intervals to first ovulation in cows with greater body condition loss. Patterns in daily energy balance, such as improvement from nadir, have been correlated with enhanced follicular function and a shorter interval to first ovulation. Such observations are consistent with increased LH pulse frequency following the energy balance nadir in lactating dairy cows. Evidence indicates a primarily hypothalamic locus for the modulation of LH secretion during negative energy balance. Formation of follicular waves after parturition begins synchronously in response to increased FSH in the first week postpartum, and is typically not a limiting factor in reproductive recrudescence. Altered follicular responsiveness to gonadotrophic support through changes in metabolic hormones such as insulin-like growth factor I (IGF-I) and insulin may contribute to impaired function of dominant follicles early postpartum. Positive relationships between changes in energy balance, peripheral IGF-I and function of dominant follicles support the identification of IGF-I and the day of the energy balance nadir as metabolic modulators of postpartum ovarian activity in dairy cows.

Animals↗
PubMed1998

Development of a quantitative chemical ionization gas chromatography-mass spectrometry method to detect tuberculostearic acid in body fluids.

We developed a mass spectral method to verify the detection of free tuberculostearic acid (TSA) by frequency-pulsed electron-capture gas chromatography (FPEC-GC) in cerebrospinal fluid (CSF), serum, pericardial fluid, ascites fluid and pleural fluid of patients infected with Mycobacterium tuberculosis. To obtain satisfactory sensitivity and specificity for comparison of the test using mass spectrometry (MS) in the single ion monitor (SIM) mode to the FPEC-GC test, we developed a specific, sensitive, quantitative chemical ionization mass spectrometry capillary gas chromatography (QCIGC-MS) test. The procedure maximized the molecular ion (i.e., made it the base peak) for increased specificity and sensitivity, and instrument parameters for increased sensitivity. The procedure uses a computerized approach, requiring an internal standard (nonadecanoic acid) for precise measurement of the retention time and quantitation of the molecular ion of TSA. Data from this study suggest that QCIGC-MS analysis could be a valuable tool to confirm FPEC-GC identification of TSA in CSF, serum, and in pleural, ascites, and pericardial fluids.

Ascitic Fluid↗
PubMed1998

Clinical and microbiological assessment of Mycobacterium simiae isolates from a single laboratory in southern Arizona.

Mycobacterium simiae was the third most common mycobacterium identified over a 2-year period from a single clinical laboratory in southern Arizona. Thirty-three isolates from 25 patients were identified over 1 year. The isolation of M. simiae was considered clinically significant for only two of 23 evaluable patients. None of five patients with human immunodeficiency virus infection had clinical disease associated with M. simiae. Twenty isolates were available for detailed study. All but one of the 20 isolates were niacin-negative, and 11 were nonphotochromogenic. All 20 isolates had a triple-cluster pattern consistent with M. simiae by high-performance liquid chromatography, and restriction fragment patterns were identical for 16 isolates. Analysis of 16S rDNA confirmed the identity of all the tested isolates as M. simiae. In this study, M. simiae was a frequent clinical isolate but was rarely associated with disease. The organisms isolated were confirmed to be M. simiae but appeared to be phenotypically distinct strains of low virulence.

Adult↗
PubMed1998

Pseudo-outbreak of tuberculosis in an acute-care general hospital: epidemiology and clinical implications.

A 10-fold increase in patients with Mycobacterium tuberculosis-positive specimens in one hospital laboratory prompted an investigation. Clinical and epidemiological data, along with M tuberculosis DNA fingerprinting results, indicated that laboratory contamination led to nine false-positive M tuberculosis cultures. Pseudo-infection should be considered in patients with unusual tuberculosis presentations, negative acid-fast bacilli smears, and only one positive culture with a low colony count.

Cross Infection↗
PubMed1998

Review: effect of protein nutrition on ovarian and uterine physiology in dairy cattle.

Milk production and dry matter intake of dairy cows are stimulated in response to increased intake of dietary protein, but, unfortunately, decreased fertility is often associated with this nutritional strategy. Ruminally degradable protein or ruminally undegradable protein in excess of requirement can contribute to reduced fertility in lactating cows. Dietary protein nutrition or utilization and the associated effects on ovarian or uterine physiology have been monitored with urea nitrogen in plasma or milk; concentrations above 19 mg/dl have been associated with altered uterine pH and reduced fertility in dairy cows. The uterine pH changed dynamically and inversely with plasma urea nitrogen, signaling possible changes in the uterine milieu. Mechanisms for reduced fertility include exacerbation of negative energy balance and reduced plasma progesterone concentrations when cows were fed rations that were high in ruminally degradable intake protein. Alternatively, changes in uterine secretions that are associated with high protein intake and elevated plasma urea nitrogen might be detrimental to embryos. Bovine endometrial cells in culture respond directly to increasing urea concentrations with alteration in pH gradient but respond most notably with increased secretion of prostaglandin F2 alpha (PGF2 alpha). Increased uterine luminal PGF2 alpha interferes with embryo development and survival in cows, thus providing a plausible link between elevated plasma urea nitrogen concentrations and decreased fertility. Poor fertility in high producing dairy cows reflects the combined effects of a uterine environment that is dependent on progesterone and rendered suboptimum by the antecedent effects of negative energy balance or postpartum health problems and that is further compromised by the effects of urea resulting from intake of high dietary protein.

Animal Nutritional Physiological Phenomena↗
PubMed1998

Energy balance, metabolic hormones, and early postpartum follicular development in dairy cows fed prilled lipid.

The objectives of this study were to relate energy balance and metabolic hormones during the early postpartum period in dairy cows with dominant follicle development before first ovulation and to evaluate the effects of prilled lipid on follicular development during the first follicular wave after parturition and the postpartum anovulatory interval. At parturition, 42 cows received a control diet (4.8% fat) or a diet supplemented with prilled fatty acids (7.0% fat). Energy balance was determined daily. Ovarian follicular development was monitored by ultrasonography, and blood plasma or serum was analyzed for estradiol, progesterone, and metabolic hormones. Dry matter intake was lower in cows supplemented with dietary lipids during the first 4 wk of lactation, but energy intake, energy balance, and the postpartum anovulatory interval were similar between diets. A wave of follicular development occurred in all cows during the 2nd wk postpartum, and 50% of all cows ovulated their first dominant follicle. Numbers of follicles that were 3 to 5 mm, 6 to 9 mm, and 10 to 15 mm on d 8 postpartum were similar between diets and unrelated to energy balance or metabolic hormones. Diameter of the dominant follicle during d 8 to 14 postpartum and maximum diameter of the first-wave ovulatory follicle did not differ between diets. Cows with nonovulatory first-wave dominant follicles had lower mean plasma concentrations of estradiol during d 8 to 14 postpartum, a longer interval to the day of the energy balance nadir, lower serum concentrations of IGF-I, and higher 4% FCM yield than did cows with ovulatory first-wave dominant follicles. Serum IGF-I during d 1 to 13 was positively correlated with plasma estradiol during d 8 to 14 postpartum. Possibly because of reductions in dry matter intake, the consumption of prilled lipid by dairy cows during early lactation may be ineffective in altering energy balance, follicular development, and the postpartum anovulatory interval. Ovulation failure of dominant follicles early in the postpartum period is associated with greater production of 4% fat-corrected milk, a delayed energy balance nadir, and reduced concentrations of peripheral IGF-I.

Animals↗
PubMed1997

Energy balance and ovarian follicle development prior to the first ovulation postpartum in dairy cows receiving three levels of dietary fat.

The objectives of this study were to characterize early postpartum (PP) follicular development in dairy cows and to evaluate the influence of energy balance (EB) and the level of dietary fat on dominant follicle development and function. Forty-five multiparous Holstein cows were fed either low (LF, 3.3%), moderate (MF, 5.2%), or high (HF, 7.1%) total dietary fat beginning at parturition, and daily EB was determined for all cows. Follicular development was monitored by ultrasonography, and blood plasma was analyzed for metabolites, metabolic hormones, progesterone, estradiol, and FSH. After an increase (p < 0.01) in mean plasma FSH during Days 1-5, all cows experienced a wave of follicular development during the second week PP regardless of diet or EB. Feeding the MF (p < 0.05) or HF (p < 0.06) diet resulted in a greater number of class IV (> 15 mm) follicles on Day 14 PP as compared to the LF diet. Cows fed the MF diet had higher (p < 0.05) peak plasma estradiol during the first follicular wave and a shorter (p < 0.05) interval to first ovulation than both LF and HF cows. Follicular development prior to first ovulation was characterized by either ovulation of the first dominant follicle (OV, n = 19), one or more waves of nonovulatory dominant follicles (NOV, n = 18), or the formation of a follicular cyst (CYST, n = 8). Ovulation failure during the first follicular wave PP was accompanied by lower (p < 0.001) peak plasma estradiol (0.96 +/- 0.36 vs. 5.0 +/- 0.35 pg/ml), a smaller (p < 0.01) maximum follicle diameter (16.0 +/- 0.9 vs. 20.0 +/- 1.0 mm), lower (p < 0.09) levels of plasma insulin-like growth factor-I (IGF-I; 73.5 +/- 10.1 vs. 102.9 +/- 9.9 ng/ml), and a longer (p < 0.02) interval to the EB nadir (14.6 +/- 1.9 vs. 6.4 +/- 1.9 days). The number of days to first ovulation was positively correlated with days to the EB nadir (r = 0.55), with dominant follicles that emerged after the EB nadir exhibiting enhanced (p < 0.01) production of estradiol and greater (p < 0.01) ovulatory success. The development of large (> 10 mm) dominant follicles was not a limiting factor in PP reproductive recovery, and moderate dietary fat shortened the interval to first ovulation. Follicular competence early PP was associated with higher plasma IGF-I and a shorter interval to the EB nadir.

Animals↗
PubMed1997

A new agent of mycobacterial lymphadenitis in children: Mycobacterium heidelbergense sp. nov.

Nontuberculous mycobacterial lymphadenitis presents an increasing clinical problem in immunocompetent young children. A slowly growing, nonphotochromogenic mycobacterium was recovered twice (isolates 2553/91 and 2554/91) from the lymphatic tissue of a child with recurrent cervical lymphadenitis. It could be differentiated biochemically from described Mycobacterium species, although it most closely resembled Mycobacterium malmoense by thin-layer chromatography and high-performance liquid chromatography of mycolic acids. A striking characteristic of the isolate was its high degree of susceptibility to antituberculous drugs in vitro, including isoniazid. Direct determination of the 16S rRNA gene sequence revealed a unique sequence and positioned the strain phylogenetically on a branch separate from M. malmoense within a group of slowly growing mycobacteria that show a high degree of similarity to M. simiae at the 16S rRNA gene level. Despite 99.6% sequence identity with M. simiae at the 16S rRNA gene level, DNA-DNA hybridization studies (hydroxyapatite method) demonstrated DNA relatedness of less than 40%. We conclude that this organism is a new species for which we propose the name M. heidelbergense. A culture of the type strain, strain 2554/91, has been deposited in the American Type Culture Collection as strain ATCC 51253.

Antitubercular Agents↗
PubMed1997

Reduced fertility associated with low progesterone postbreeding and increased milk urea nitrogen in lactating cows.

The primary objectives of this study were to determine whether a delay in the onset of the luteal phase, or high milk urea nitrogen at breeding, or both were associated with failure of pregnancy early in gestation. Milk samples were collected twice daily from cows in a single herd during the week following breeding; single samples were collected on d 14 and 21 postbreeding. Progesterone was measured in all samples, and a total of 156 sample sets was used. The progesterone data combined with results from pregnancy examinations were used to distribute the cows into three groups: 1) pregnant, 2) nonpregnant with a low concentration (< 2 ng/ml) of progesterone on d 21, and 3) nonpregnant with a high concentration (> or = 2 ng/ml) of progesterone on d 21. The interestrous interval for cows in group 3 was longer than that for cows in group 2. Beginning 4.5 d after breeding, pregnant cows had higher concentrations of progesterone than did cows in group 3. Pregnant cows also had higher concentrations of progesterone than did all open cows on d 14 and 21. The onset of the luteal phase was earlier in pregnant cows than it was in cows in group 3. Milk urea nitrogen at breeding was similar in pregnant cows and in cows in group 3, but was higher in cows in group 2. Increased milk urea nitrogen was also statistically associated with decreased fertility. We propose that the cows in group 3 likely had embryos that initiated pregnancy recognition and prolonged luteal function, but these embryos were compromised by suboptimal exposure to progesterone early in development.

Animals↗
PubMed1996

Naloxone administration does not relieve the inhibition of gonadotropin release in food-restricted, lactating rats.

Lactational anovulation is an important factor in determining birth spacing in women living in developing countries. Therefore, a more comprehensive understanding of the mechanisms involved in the relationships among lactation, nutrition and ovulation is important. This study was designed using the food-restricted, lactating rat to examine whether endogenous opioids might be involved in depressing gonadotropin release. Females were mated after 65 d of age and, beginning on d 42 of life, offered food in unrestricted amounts (control) or were food restricted to 50% of what the controls consumed. On d 15 of lactation, dams were injected with either naloxone hydrochloride (3 mg/kg body weight) or saline and killed 0, 15, 30 or 60 min later. Plasma was analyzed for luteinizing hormone, follicle-stimulating hormone and prolactin. Food restriction decreased plasma concentrations of luteinizing hormone and follicle-stimulating hormone (P < 0.005). Naloxone administration marginally influenced follicle stimulating hormone (P < 0.1), but not luteinizing hormone concentration regardless of diet group. The interaction among diet group, drug group and time of killing was significant for plasma prolactin concentration (P < 0.05). Food restriction lowered prolactin concentrations, but this effect was diminished with increasing time after injection of naloxone. Furthermore, the magnitude of the effect of food restriction was lessened and even reversed with treatment of naloxone. These results indicate that endogenous opioids are not the primary mechanism suppressing luteinizing hormone release in food-restricted lactating rats.

Animals↗
PubMed1996

Characterization of an SAV organism and proposal of Mycobacterium triplex sp. nov.

Polyphasic taxonomic methods were employed to characterize a new species of slowly growing, nonpigmented mycobacteria. We propose the name Mycobacterium triplex sp. nov. for this new taxon. Conventional identification testing demonstrated a group of similar organisms that were geographically widespread in the United States. Commercially available nucleic-acid probes specific for the Mycobacterium avium complex were unreactive for these strains. High-performance liquid chromatography analysis of the mycolic acids revealed mycolate profiles that closely resembled Mycobacterium simiae. Comparative 16S rRNA sequence data confirmed the phylogenetic relationship of the strains with the slowly growing mycobacteria. Representative-type strains have been deposited in the American Type Culture Collection as strain ATCC 700071 [corrected].

Bacterial Typing Techniques↗
PubMed1996

Identification and differentiation of Mycobacterium avium and M. intracellulare by PCR.

Known DNA sequences coding for the 16S rRNAs of 14 slowly growing Mycobacterium species were analyzed. Three sets of primers were synthesized: MAV and MIN, for M. avium and M. intracellulare, respectively, and MYCOB, for the slowly growing mycobacteria. Whole-cell DNAs of 14 reference species were extracted and amplified by PCR with the MYCOB, MAV, and MIN primers. The MYCOB primer amplified a 0.9-kb segment from the DNAs of all 14 species. The MAV and MIN primers each amplified one highly specific 1.3-kb segment from the homologous DNA, respectively. DNAs from each of 10 clinical isolates of M. avium and M. intracellulare identified by conventional methods were amplified with the MYCOB as well as the MAV and MIN primers; 9 of 10 isolates of each species were identified with their respective primers. One isolate of M. intracellulare was subsequently found to have been mislabeled. One isolate designated M. avium reacted only with the MYCOB primer. The hypervariable region of this strain was shown by DNA sequence analysis to be distinct from all known 16S rRNA sequences of Mycobacterium spp. Our data indicate that the currently identified M. avium-M. intracellulare complex includes strains genetically diverse from M. avium and M. intracellulare.

Bacterial Typing Techniques↗