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Biomedical subjects

B Campbell

Publications and source records attributed to B Campbell.

At least 19 recordsLinked to original sources
PubMed2006

Previtellogenic oocyte growth in salmon: relationships among body growth, plasma insulin-like growth factor-1, estradiol-17beta, follicle-stimulating hormone and expression of ovarian genes for insulin-like growth factors, steroidogenic-acute regulatory protein and receptors for gonadotropins, growth hormone, and somatolactin.

Body growth during critical periods is known to be an important factor in determining the age of maturity and fecundity in fish. However, the endocrine mechanisms controlling oogenesis in fish and the effects of growth on this process are poorly understood. In this study interactions between the growth and reproductive systems were examined by monitoring changes in various components of the FSH-ovary axis, plasma insulin-like growth factor 1 (Igf1), and ovarian gene expression in relation to body and previtellogenic oocyte growth in coho salmon. Samples were collected from females during two hypothesized critical periods when growth influences maturation in this species. Body growth during the fall-spring months was strongly related to the degree of oocyte development, with larger fish possessing more advanced oocytes than smaller, slower growing fish. The accumulation of cortical alveoli in the oocytes was associated with increases in plasma and pituitary FSH, plasma estradiol-17beta, and ovarian steroidogenic acute regulatory protein (star) gene expression, whereas ovarian transcripts for growth hormone receptor and somatolactin receptor decreased. As oocytes accumulated lipid droplets, a general increase occurred in plasma Igf1 and components of the FSH-ovary axis, including plasma FSH, estradiol-17beta, and ovarian mRNAs for gonadotropin receptors, star, igf1, and igf2. A consistent positive relationship between plasma Igf1, estradiol-17beta, and pituitary FSH during growth in the spring suggests that these factors are important links in the mechanism by which body growth influences the rate of oocyte development.

Animals↗
PubMed2006

Flooring in front of the feed bunk affects feeding behavior and use of freestalls by dairy cows.

In 2 experiments we assessed how preferences, time budgets, and feeding behavior of dairy cows change in response to flooring surfaces in front of the feed bunk. In Experiment 1, 12 nonlactating dairy cattle were individually housed with access to 2 standing platforms filled with either concrete or sawdust. In Experiment 2, 24 nonlactating dairy cattle were given access to either concrete or Animat rubber flooring in front of the feed bunk. In Experiment 1, cows preferred the sawdust to the concrete flooring. In both experiments, cows provided with a softer floor in front of the feed bunk spent more time standing near the feed bunk without eating (Experiment 1: 67 vs. 40 min/d on sawdust vs. concrete, respectively, SEM = 5.6 min/d; Experiment 2: 176 vs. 115 min/d on Animat vs. concrete, respectively, SEM = 20.5 min/d) compared with when they were kept on concrete. The increased time spent at the feed bunk was due to a combination of more frequent eating and standing bouts, indicating that cows were more willing to move on nonconcrete flooring. Total time spent eating was significantly greater on the softer floor in Experiment 2, but not in Experiment 1 (Exp. 1: 289 vs. 275 min/d on sawdust and concrete, respectively, SEM = 7.3 min/d; Exp. 2: 330 vs. 289 min/d on Animat and concrete, respectively, SEM = 15.4), although feed intake was increased on the sawdust treatment in Experiment 1. Cows spent significantly more time lying in the feed alley when the flooring was rubber (219 vs. 53 min/d on Animat and concrete, SEM = 53.6 min/d), perhaps because the lying area in Experiment 2 was inadequate. In conclusion, cows prefer to stand on softer flooring in front of the feed bunk, and are more willing to move on and spend more time standing in front of the feed bunk when provided with softer flooring. These results indicate that cows find softer flooring surfaces more comfortable to stand on than concrete, and highlight the importance of evaluating the comfort of the entire facility.

Animal Welfare↗
PubMed2005

Immune responses to the 105AD7 human anti-idiotypic vaccine after intensive chemotherapy, for osteosarcoma.

105AD7 is a human monoclonal antibody that mimics the complement regulatory protein, CD55, overexpressed by many solid tumours including osteosarcoma. This study was designed to assess the toxicity and efficacy of this vaccine in a young age group of patients within 1-6 months of myleosuppressive chemotherapy. Out of 28, 20 (71%, 95% CI 51-87%) patients showed a significant T-cell proliferation response in vitro to the 105AD7 protein but not to human IgG. Furthermore, 13 out of 22 (59%, 95% CI 36-79%) patients showed antigen-specific gammaIFN secretion (range 20-370 U/ml). Nine out of 28 (32%, 95% CI 16-52%) patients made weak antibody responses to CD55. This study showed that 105AD7 was well tolerated in younger patients with osteosarcoma. In addition, two patients with possible clinical responses were given compassionate permission to continue immunisation quarterly for 2 years. They both remain alive and disease free 5.8 and 6.5 years from original diagnosis of osteosarcoma and showed no adverse effects of repeated immunisation. In conclusion, the majority of patients showed measurable T helper responses when vaccination was commenced within a 6-month window of intensive chemotherapy with no clinically significant toxicity. Future clinical trials incorporating immune stimulation strategies should include early introduction of vaccines during the highest risk period for relapse.

Adult↗
PubMed2005

Comparison of the antinociceptive profiles of gabapentin and 3-methylgabapentin in rat models of acute and persistent pain: implications for mechanism of action.

The anticonvulsant gabapentin (GBP) has been shown effective for the treatment of neuropathic pain, although its mechanism of action remains unclear. A recent report has suggested that binding to the alpha(2)delta subunit of voltage-gated calcium channels contributes to its antinociceptive effect, based on the stereoselective efficacy of two analogs: (1S,3R)3-methylgabapentin (3-MeGBP) (IC(50) = 42 nM), which is effective in neuropathic pain models; and (1R,3R)3-MeGBP (IC(50) > 10,000 nM), which is ineffective (Field et al., 2000). The present study was designed to further examine the profiles of GBP and 3-MeGBP in rat models of acute and persistent pain. Systemic administration of GBP or (1S,3R)3-MeGBP inhibited tactile allodynia in the spinal nerve ligation model of neuropathic pain, whereas (1R,3R)3-MeGBP was ineffective. The antiallodynic effect of GBP, but not (1S,3R)3-MeGBP, was blocked by i.t. injection of the GABA(B) receptor antagonist [3-[[(3,4-dichlorophenyl)methyl]amino]propyl](diethoxymethyl)phosphinic acid (CGP52432). Systemic GBP or (1S,3R)3-MeGBP also inhibited the second phase of formalin-evoked nociceptive behaviors, whereas (1R,3R)3-MeGBP was ineffective. However, both (1S,3R)3-MeGBP and (1R,3R)3-MeGBP, but not GBP, inhibited first phase behaviors. In the carrageenan model of inflammatory pain, systemic GBP or (1R,3R)3-MeGBP failed to inhibit thermal hyperalgesia, whereas (1S,3R)3-MeGBP had a significant, albeit transient, effect. Systemic (1S,3R)3-MeGBP, but not GBP or (1R,3R)3-MeGBP, also produced an antinociceptive effect in the warm water tail withdrawal test of acute pain. These data demonstrate that GBP and 3-MeGBP display different antinociceptive profiles, suggesting dissimilar mechanisms of antinociceptive action. Thus, the stereoselective efficacy of 3-MeGBP, presumably related to alpha(2)delta binding, likely does not completely account for the mechanism of action of GBP.

Acetates↗
PubMed2003

Endocrine changes during onset of puberty in male spring Chinook salmon, Oncorhynchus tshawytscha.

In male salmonids, the age of maturation varies from 1 to 6 years and is influenced by growth during critical periods of the life cycle. The endocrine mechanisms controlling spermatogenesis and how growth affects this process are poorly understood. Recent research has indicated that gonadotropins, 11-ketotestosterone, and insulin-like growth factor I play roles in spermatogenesis in fish. To expand our understanding of the roles of these endocrine factors in onset of puberty, male spring chinook salmon (Oncorhynchus tshawytscha) were sampled at monthly intervals 14 mo prior to spermiation. This sampling regime encompassed two hypothesized critical periods when growth influences the initiation and completion of puberty for this species. Approximately 80% of the males matured during the experimental period, at age 2 in September 1999. An initial decline in the ratio of primary A to transitional spermatogonia was observed from July to December 1998, and during this period plasma levels of 11-ketotestosterone and pituitary levels of FSH increased. From January 1999 onward, males with low plasma 11-ketotestosterone levels (<1 ng/ml) had low pituitary and plasma FSH levels and no advanced development of germ cells. Conversely, from January through September 1999, males with high plasma 11-ketotestosterone levels (>1 ng/ml) had testes with progressively more advanced germ cell stages along with elevated pituitary and plasma FSH. Plasma levels of insulin-like growth factor I increased during maturation. These data provide the first physiological evidence for activation of the pituitary-testis axis during the fall critical period when maturation is initiated for the following year.

Animals↗
PubMed2002

Glass transition in the polaron dynamics of colossal magnetoresistive manganites.

Neutron scattering measurements on a bilayer manganite near optimal doping show that the short-range polaron correlations are completely dynamic at high T, but then freeze upon cooling to a temperature T(*) approximately equal 310 K. This glass transition suggests that the paramagnetic/insulating state arises from an inherent orbital frustration that inhibits the formation of a long-range orbital- and charge-ordered state. Upon further cooling into the ferromagnetic-metallic state (T(C) = 114 K), where the polarons melt, the diffuse scattering quickly develops into a propagating, transverse optic phonon.

Journal Article↗
PubMed2002

The reproducibility of endometrial volume acquisition and measurement with the VOCAL-imaging program.

OBJECTIVES: To determine the intraobserver reproducibility of volume acquisition and repeatability of endometrial volume measurements using the VOCAL-imaging program (Virtual Organ Computer-aided AnaLysis). METHODS: Ten three-dimensional (3D) ultrasound datasets of the same endometrium were obtained from one patient during one scan session. For every 3D dataset, the endometrial volume was calculated by four different measurement techniques; three rotational methods and one conventional method. A single observer acquired each dataset and conducted all measurements. For the rotational technique, the manual mode was used to trace the myometrial-endometrial border through three different predefined rotations of 30 degrees, 15 degrees and 9 degrees . Endometrial volume was also measured in a conventional manner by scrolling through one of the multiplanar images and outlining the contour in another. Ten consecutive measurements were taken for each of the four measurement techniques so that 40 endometrial volume readings were obtained for each of the 10 3D-ultrasound datasets. RESULTS: Endometrial volume measurements were more reproducible with the rotational technique. Rotational methods employing a rotation step of less than 30 degrees were associated with coefficients of variation below 1% and intraclass correlation coefficients above 0.94. Within each of the 10 different scans, the homogeneity of the variance of measurements was significantly different according to the method of measurement (P = 0.022 to < 0.001). Post-hoc tests revealed that both the conventional and 30 degrees rotational methods resulted in a significantly smaller mean endometrial volume than both the 15 degrees and the 9 degrees rotational methods. CONCLUSIONS: Endometrial volume acquisition is reproducible and endometrial volume measurements are repeatable but they depend upon the technique of volume calculation in so much as rotational methods employing a rotation step of less than 30 degrees are associated with a significantly smaller variance in measurements and a significantly greater mean endometrial volume.

Adult↗
PubMed2001

Effect of cold ischemic time and HLA matching in kidneys coming from "young" and "old" donors: do not leave for tomorrow what you can do tonight.

BACKGROUND: Kidneys from older donors are likely to have a lower nephron mass. Nevertheless they constitute a valuable source of kidney allografts. Long cold ischemic time (CIT), with or without delayed graft function (DGF), has been associated with reduced graft survival. The aim of this study was to review the experience of a single UK center to assess the interaction of cold storage time, donor age, organ exchange, and HLA-DR mismatching on short- and long-term survival. METHODS: We analyzed 788 first cadaver kidney transplants that were performed in our center from 1990 to 1997 and had complete data available. A donor age of 55 years was the cutoff age for "old" and "young" donor kidneys. The primary outcome measured was graft failure from any cause. RESULTS: There were 132 grafts from donors 55 years or older (16.7%), with 76.8% of the kidneys implanted after >20 hr of CIT. Kidney grafts from donors older than 55 years had worse graft survival than grafts from donors younger than 55 (87% vs. 78% at 1 year and 80% vs. 58% at 5 years after transplant, P=0.0001). A CIT of >20 hr significantly reduced graft survival (91% vs.74.3% at 5 years after transplant, P=0.0002) in the young donor group and was associated with an overall graft survival in the old donor group of 57.5% at 5 years. In the same group, ignoring the HLA-DR mismatching to achieve shorter CIT, the predicted initial cost on graft survival at 1 year would have been 3.7% but would have increased to 9% 5 years after transplant. For young donors a CIT of >20 hr had a cost of approximately 18% at 5-year graft survival, far higher than a single DR mismatch. Occurrence of DGF decreased survival in both short (P=0.001) and long (P=0.00001) CIT groups. CONCLUSION: Forming local alliances (common recipient lists) and minimizing delays within the hospital might reduce CIT and DGF while achieving excellent HLA matching. This should improve significantly the outcome of both old and young donor kidney grafts.

Aging↗
PubMed2001

Blood lead levels in Jamaican school children.

Blood lead levels are reported for a total of 421 schoolchildren in 13 schools in rural and urban environments in Jamaica, including one highly contaminated community. In the rural areas blood lead levels ranged from 3 to 28.5 microg dl(-1), with a median of 9.2 microg dl(-1); the range and median in the urban schools were 4-34.7 and 16.6 microg dl(-1), respectively. Forty-two percent of the rural and 71% of the urban blood lead levels exceeded the US Centers for Disease Control and Prevention intervention level of 10 microg dl(-1). Except in the contaminated area, the relationship between soil lead levels, which in Jamaica are in general typical of tropical lateritic soils, and blood lead levels is not clear-cut. Very high blood lead levels of 18 to > 60 microg dl(-1) with a median of 35 microg dl(-1) were observed among children in the contaminated area, the site of a former lead ore processing plant. These high blood lead levels were significantly reduced, by the implementation of relatively simple mitigation strategies which involved isolation of the lead, education, and a food supplementation programme, to levels similar to those observed in the urban schools. These values, however, remain higher than are desirable and unfortunately, all the sources of lead are not yet identified. The recent discontinuation of the use of leaded petrol is expected to result in significant reductions in exposure to lead.

Child↗
PubMed2001

Chromosome 15 aneuploidy in the sperm and conceptus of a sibling with variable familial expression of round-headed sperm syndrome.

OBJECTIVE: To characterize rates of chromosome aneuploidy in sperm from three siblings, one of whom had an IVF/ICSI conceptus with trisomy 15. DESIGN: Blind evaluation of the sperm chromosome aneuploidy rates, semen quality, and sperm ultrastructure. SETTING: IVF clinic and university-based andrology research laboratory. PATIENT(S): Three brothers, two of whom underwent infertility evaluation and therapy. MAIN OUTCOME MEASURE(S): Semen from three siblings was coded and blindly evaluated for standard World Health Organization semen quality variables and sperm ultrastructure. Sperm were decondensed and hybridized with fluorescent probes specific for chromosomes X, Y, 13, 15, 18, and 21, then evaluated microscopically to determine the aneuploidy rate for those chromosomes. RESULT(S): Two siblings had increased round-headed morphology on standard morphology evaluation, which was confirmed using electron microscopy. The sperm aneuploidy rate was significantly increased for chromosome 15 in sibling 1, the father of a conceptus with trisomy 15. Aneuploidy rates were also slightly increased for chromosomes X, Y, and 18 in sibling 1. CONCLUSION(S): This is the second report of increased sperm chromosome aneuploidy in infertile patients with round-headed sperm. Although ICSI is successful in treating this syndrome, the risk for aneuploidy of the conceptus may be increased. Other studies have reported an increased incidence of sperm chromosome aneuploidy in some infertile patients, but this is the first report of aneuploidy in both the sperm and conceptus of a patient undergoing IVF/ICSI.

Abortion, Spontaneous↗
PubMed2001

Evidence for the presence of thermophilic Fe(III)-reducing microorganisms in deep-sea hydrothermal vents at 13 degrees N (East Pacific Rise).

Microorganisms capable of dissimilatory Fe(III) reduction in the temperature range of 52-90 degrees C were enriched from outer and inner parts of chimney-like structures, tubes of the polychaetous annelid Alvinella sp., and hydrothermal fluids collected at 13 degrees N hydrothermal vent sites on the East Pacific Rise at a depth of 2650 m. Numbers of culturable Fe(III)-reducing thermophiles estimated by the serial dilution technique varied from 10 to 10(7) cells per cm(3) of sample. Phylogenetic analysis of bacterial and archaeal PCR-amplified 16S rDNA genes obtained from Fe(III)-reducing enrichments and separated by denaturing gradient gel electrophoresis revealed sequences related to Deferibacter, Thermotogales (Bacteria) and Thermococcus (Archaea) for which the capacity for Fe(III) reduction had been reported. This was confirmed by isolating a hyperthermophilic iron reducer that belongs to the genus Thermococcus. Other bacterial thermophiles found in the enrichments were related to so far uncultured members of the Clostridiaceae, and epsilon-subdivision of the Proteobacteria.

Journal Article↗