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McCormack MC, Breysse PN, Hansel NN, Matsui EC, Tonorezos ES, Curtin-Brosnan J, Williams DL, Buckley TJ, Eggleston PA, Diette GB. Common household activities are associated with elevated particulate matter concentrations in bedrooms of inner-city Baltimore pre-school children. ENVIRONMENTAL RESEARCH 2008; 106:148-55. [PMID: 17927974 PMCID: PMC2291550 DOI: 10.1016/j.envres.2007.08.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Revised: 07/25/2007] [Accepted: 08/22/2007] [Indexed: 05/20/2023]
Abstract
Asthma disproportionately affects inner-city, minority children in the U.S. Outdoor pollutant concentrations, including particulate matter (PM), are higher in inner-cities and contribute to childhood asthma morbidity. Although children spend the majority of time indoors, indoor PM exposures have been less extensively characterized. There is a public health imperative to characterize indoor sources of PM within this vulnerable population to enable effective intervention strategies. In the present study, we sought to identify determinants of indoor PM in homes of Baltimore inner-city pre-school children. Children ages 2-6 (n=300) who were predominantly African-American (90%) and from lower socioeconomic backgrounds were enrolled. Integrated PM(2.5) and PM(10) air sampling was conducted over a 3-day period in the children's bedrooms and at a central monitoring site while caregivers completed daily activity diaries. Homes of pre-school children in inner-city Baltimore had indoor PM concentrations that were twice as high as simultaneous outdoor concentrations. The mean indoor PM(2.5) and PM(10) concentrations were 39.5+/-34.5 and 56.2+/-44.8 microg/m(3), compared to the simultaneously measured ambient PM(2.5) and PM(10) (15.6+/-6.9 and 21.8+/-9.53 microg/m(3), respectively). Common modifiable household activities, especially smoking and sweeping, contributed significantly to higher indoor PM, as did ambient PM concentrations. Open windows were associated with significantly lower indoor PM. Further investigation of the health effects of indoor PM exposure is warranted, as are studies to evaluate the efficacy of PM reduction strategies on asthma health of inner-city children.
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Williams DL, Pierce V, Mellor P, Heath MF. Reduced tear production in three canine endocrinopathies. J Small Anim Pract 2007; 48:252-6. [PMID: 17425694 DOI: 10.1111/j.1748-5827.2007.00349.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Previous reports have suggested that hypothyroid and diabetic patients can be predisposed to keratoconjunctivitis sicca. This study aimed to measure tear production in dogs with diabetes, hypothyroidism and hyperadrenocorticism using the Schirmer tear test and to compare these results with Schirmer tear test values for a group of normal dogs. METHODS Schirmer tear tests were performed on 16 dogs with hyperadrenocorticism, 18 with diabetes and 12 with hypothyroidism together with 100 control dogs. Corneal sensitivity was also measured in 12 of the 18 diabetic dogs with a Cochet Bonnet aesthesiometer and compared with age- and breed-matched normal dogs. RESULTS Schirmer tear test values in dogs with hypothyroidism, hyperadrenocorticism and diabetes were 12.3+/-3.2, 14.0+/-4.0 and 12.3+/-5.3 mm/minutes, respectively. Schirmer tear test values were significantly lower than that for the control group (19.6+/-4.2 mm/minutes) in all dogs with an endocrinopathy. Only in two hypothyroid dogs and three diabetics, this was manifested as profound keratoconjunctivitis sicca with Schirmer tear test value lower than 5 mm/minutes. Diabetic dogs had significantly reduced corneal sensitivity compared with a matched set of control dogs. CLINICAL SIGNIFICANCE This study shows a significant reduction in tear production in animals with diabetes mellitus, hypothyroidism and hyperadrenocorticism. Further research is needed to elucidate the mechanisms by which this reduction in tear production occurs. Assessment of tear production should be undertaken in animals diagnosed with these endocrinopathies, as these animals may progress to clinical keratoconjunctivitis sicca.
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Williams DL, Brancker WM. Aggravating factors in the development of ocular abnormalities in farmed Atlantic halibut (Hippoglossus hippoglossus). Vet J 2006; 172:501-5. [PMID: 16309935 DOI: 10.1016/j.tvjl.2005.08.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/09/2005] [Indexed: 10/25/2022]
Abstract
Cystic lesions in the eyes of farmed halibut with a number of ocular sequelae have been reported previously with evidence that the condition can be associated with increased activity of choroidal carbonic anhydrase and elevated oxygen tension in the aqueous humour of affected fish. These changes may be compared to the 'bends' in human divers which are characterized by elevated circulating levels of nitrogen together with aggravating factors such as physical exercise. It is postulated that bubble formation and subsequent development of cysts in halibut require not only high aqueous humour oxygen tension but also the imposition of factors such as handling or intraspecific aggression which lead to bubble formation. A significantly higher incidence of lesions was noted in fish handled, weighed and measured every two weeks compared with a control group of unhandled fish, suggesting that physical activity associated with handled and possibly also intraspecific aggression is a factor in generation of ocular lesions in these fish.
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Williams DL, Grill HJ, Cummings DE, Kaplan JM. Overfeeding-induced weight gain suppresses plasma ghrelin levels in rats. J Endocrinol Invest 2006; 29:863-8. [PMID: 17185893 DOI: 10.1007/bf03349188] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The elevation of plasma ghrelin associated with weight loss has been taken as evidence of a role for ghrelin in the adaptive response to body weight change. However, there has been no clear experimental evidence that circulating ghrelin is suppressed by weight gain. We investigate this issue using a model of involuntary (intra-gastric gavage) overfeeding-induced obesity. Rats were first maintained at normal body weight with 4 daily tube-feedings of liquid diet (2.11 kcal/ml), each delivered at a volume of 9 ml. Gavage volume was then increased to 13 ml/feeding for 2 weeks, during which rats gained 25% of their initial body weight. Fasting plasma ghrelin levels and the response to 9- and 13-ml intra-gastric load sizes were measured during the weight-stable and overfed conditions. We found that: 1) weight gain decreased circulating ghrelin levels; 2) this response could not be attributed to additional food in the gastrointestinal tract; 3) the ghrelin response to nutrient loads was diminished in the obese vs normal-weight conditions. Having discounted diet composition and differences in gastric contents at the time of blood sampling, the decrease in ghrelin levels with overfeeding can be unambiguously attributed to physiological correlates of weight gain.
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Williams DL, Gonzalez Villavincencio CM, Wilson S. Chronic ocular lesions in tawny owls (Strix aluco
) injured by road traffic. Vet Rec 2006; 159:148-53. [PMID: 16877681 DOI: 10.1136/vr.159.5.148] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The chronic ocular lesions suffered by 50 tawny owls (Strix aluco) injured by road traffic were investigated. They included non-healing corneal erosions, cataracts and retinal scarring, and periretinal membrane formation. The intraocular pressure was significantly lower in the eyes with intraocular inflammatory pathology and higher in the eyes with irido- or cyclodialysis than in ophthalmically normal eyes. Cicatritial retinal lesions were not associated with high titres of antibodies to Toxoplasma species. The findings correlate with those observed in human beings with eye injuries due to high-speed blunt trauma.
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Williams DL. Major histocompatibility class II expression in the normal canine cornea and in canine chronic superficial keratitis. Vet Ophthalmol 2006; 8:395-400. [PMID: 16359362 DOI: 10.1111/j.1463-5224.2005.00412.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To compare the expression of major histocompatibility complex (MHC) class II antigen in the corneas of normal dogs and dogs affected with chronic superficial keratitis (CSK). METHODS MHC class II expression was determined in frozen sections of normal canine cornea and cornea from lesions of CSK by immunohistochemistry using a monoclonal antibody directed against the canine MHC class II molecule. Langerhans cell phenotype was determined morphologically and by histochemical determination of ATPase activity. To determine the influence of gamma interferon on expression of MHC class II molecules by corneal cells, corneal explants were cultured with the cytokine and MHC class II expression determined as above. RESULTS Numerous MHC class II-expressing cells were demonstrated within the stroma and epithelium of the normal corneal limbus and conjunctival epithelium while very little MHC class II expression was detected in the central region of normal canine cornea. In limbal and conjunctival epithelium, cells expressing MHC class II antigen showed ATPase activity, suggesting that they were Langerhans cells. Corneas from dogs with CSK showed MHC class II expression associated with stromal cells, some of which exhibited a dendritic morphology while most were lymphocytic. Corneal epithelial cells within the lesion also aberrantly expressed MHC class II. Corneal explants expressed MHC class II to varying degrees after differing periods of incubation with the cytokine gamma interferon. CONCLUSIONS While the normal central cornea has little MHC class II expression, aberrant expression occurs in CSK, associated with secretion of gamma interferon by infiltrating CD4-expressing lymphocytes. Although this change is likely to be a secondary feature of the CSK lesion, increased MHC class II expression may play a part in perpetuating the corneal inflammation seen in the disease.
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Scollard DM, Adams LB, Gillis TP, Krahenbuhl JL, Truman RW, Williams DL. The continuing challenges of leprosy. Clin Microbiol Rev 2006; 19:338-81. [PMID: 16614253 PMCID: PMC1471987 DOI: 10.1128/cmr.19.2.338-381.2006] [Citation(s) in RCA: 498] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Leprosy is best understood as two conjoined diseases. The first is a chronic mycobacterial infection that elicits an extraordinary range of cellular immune responses in humans. The second is a peripheral neuropathy that is initiated by the infection and the accompanying immunological events. The infection is curable but not preventable, and leprosy remains a major global health problem, especially in the developing world, publicity to the contrary notwithstanding. Mycobacterium leprae remains noncultivable, and for over a century leprosy has presented major challenges in the fields of microbiology, pathology, immunology, and genetics; it continues to do so today. This review focuses on recent advances in our understanding of M. leprae and the host response to it, especially concerning molecular identification of M. leprae, knowledge of its genome, transcriptome, and proteome, its mechanisms of microbial resistance, and recognition of strains by variable-number tandem repeat analysis. Advances in experimental models include studies in gene knockout mice and the development of molecular techniques to explore the armadillo model. In clinical studies, notable progress has been made concerning the immunology and immunopathology of leprosy, the genetics of human resistance, mechanisms of nerve injury, and chemotherapy. In nearly all of these areas, however, leprosy remains poorly understood compared to other major bacterial diseases.
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Williams DL, Goddard PJ, Brancker WM. Ultrasonographic examination of ocular lesions in farmed halibut. Vet J 2006; 173:456-8. [PMID: 16458029 DOI: 10.1016/j.tvjl.2005.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2005] [Indexed: 10/25/2022]
Abstract
This paper describes the use of ultrasound to document ocular abnormalities occurring in farmed halibut. A cystic condition of the posterior segment of farmed halibut with a number of ocular sequelae has been reported previously. Further research to elucidate the aetiology and pathogenesis of this condition requires in vivo determination of ocular health over and above that provided by ophthalmoscopy alone. Ocular ultrasonography would appear to be an optimal technique for evaluating the presence of gas- or fluid-filled cysts in the posterior segment and retrobulbar space. The aim of this study was to evaluate this technique for investigation of the piscine eye and specifically to define the role of ultrasonography to detect gas bubble formation in the choroid of farmed halibut, a factor considered central to ocular pathology in many of these fish. In particular the study sought to assess the minimum size of halibut in which intraocular cystic lesions could be identified by ultrasonography and the minimum size of lesion identified by ocular ultrasonography. A second objective was to correlate ultrasonographic findings with lesions found at post mortem ocular examination. A number of halibut of varying sizes, with and without clinically apparent ocular lesions, were subjected to examination under anaesthesia. A proportion of these fish were subsequently sacrificed to allow post mortem ocular evaluation with the aim of correlating ultrasonographic findings with intraocular pathological defects.
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Abstract
A 10-year-old, female, neutered Cairn terrier was presented with a progressively enlarging, cream-white fluctuant subconjunctival swelling in the right eye. A fine-needle aspirate performed under topical anaesthesia showed that the mass contained lipomatous tissue. Orbital ultrasonography showed the mass to have a distinct border and to extend into the posterior orbit. The mass was removed via a conjunctival incision. It had a distinct capsule anteriorly, while the border of the mass was less readily identified in the posterior orbit. Histopathological examination showed the mass to be a lipoma. The dog recovered uneventfully from surgery, and no recurrence has been noted after 12 months.
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Adams JE, Peña MT, Gillis TP, Williams DL, Adams LB, Truman RW. Expression of nine-banded armadillo (Dasypus novemcinctus) interleukin-2 in E. coli. Cytokine 2005; 32:219-25. [PMID: 16338142 DOI: 10.1016/j.cyto.2005.09.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Revised: 08/26/2005] [Accepted: 09/01/2005] [Indexed: 10/25/2022]
Abstract
The nine-banded armadillo (Dasypus novemcinctus) is the only immunologically intact animal that regularly develops lepromatous-type leprosy when inoculated with Mycobacterium leprae. However, the ability to exploit this model for understanding the pathogenesis of leprosy has been limited by a lack of suitable immunological reagents. Recently, efforts began to sequence the entire armadillo genome, and this sequence information will help make possible the development of a wide array of new immunological reagents suitable for use with armadillos. Using the available sequence data, a region of high homology to interleukin-2 of other mammals was identified. Primers were designed to amplify the coding region corresponding to the mature peptide and its exact sequence was confirmed. cDNA was made from ConA-stimulated armadillo PBMC. The amplified coding region was sub-cloned into a pET expression vector and transformed into Escherichia coli for over-expression. The subsequent product was characterized by SDS-PAGE and bioassays. Tritiated thymidine incorporation by CTLL-2 and armadillo lymphoblasts confirmed functionality of the recombinant product. The advent of the D. novemcinctus genome sequence and subsequent generation of immunological tools will assist in advancing the armadillo as a translational model for leprosy.
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Williams DL, Robinson JC, Lay E, Field H. Efficacy of topical aciclovir for the treatment of feline herpetic keratitis: results of a prospective clinical trial and data from in vitro investigations. Vet Rec 2005; 157:254-7. [PMID: 16127135 DOI: 10.1136/vr.157.9.254] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
This study aimed to evaluate the efficacy of topical ophthalmic aciclovir applied five times daily as a treatment for feline herpesvirus type 1 (FHV-1) keratitis in a group of cats in a first-opinion practice setting. Cats with ocular signs indicative of FHV-1 or Chlamydophila species infection, predominantly conjunctivitis and keratitis, were tested for FHV-1 antigen using an immunofluorescent technique on air-dried conjunctival swabs. They were first treated with topical chlortetracycline with efficacy against Chlamydophila species and then, in cases positive for FHV-1, with topical aciclovir. The time to recovery was determined and illustrated using a Kaplan-Meier plot. Three cats were infected with Chlamydophila species and showed a median time to recovery of 14 days (95 per cent confidence interval [CI] 10 to 18 days), while 30 cats infected with FHV-1 showed a median time to recovery of 12 days (95 per cent CI 10 to 14 days). The drug dose at which 50 per cent plaque reduction (ED50) occurred in a standard plaque reduction assay was determined in an in vitro study. This showed a mean (SD) ED50 of aciclovir of 25 (3.5) mg/ml compared with 0.4 (0.05) mg/ml for trifluorothymidine, a drug known to be efficacious against FHV-1. The study shows that even though aciclovir is generally considered to lack efficacy against ocular FHV-1 infection, when used frequently it can have a beneficial effect in FHV-1 conjunctivitis and keratitis.
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Abstract
Eyes from 88 otters found dead in south-west England between 1990 and 2000, were collected as part of a larger pathological study. Histopathological examination of 131 eyes revealed dysplastic changes such as rosetting and folding in the retinas of 26 of the otters. In the eyes of 42 of the otters there were postmortem and fixation-induced retinal detachment which complicated the differentiation of dysplastic from normal retina, but 11 eyes had folds which probably indicated a dysplastic pathology. The eyes of 18 of the otters had inflammatory or autolytic changes which precluded a definitive evaluation of their dysplastic status. Liver samples from 55 of the otters were analysed for a range of polychlorinated hydrocarbons and for vitamin A. The otters with dysplastic retinas had significantly lower concentrations of vitamin A and higher concentrations of dieldrin than the otters with normal retinas.
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Abstract
We have previously documented ocular abnormalities in farmed halibut and reported that the production of gas-filled posterior segment cysts appears to be central in the pathogenesis of many, if not all of the signs in these eyes. In a number of fish, gas bubbles may be seen in the anterior chamber of the eye, especially after trauma or strenuous exertion associated with handling. A knowledge of the composition of this gas is important in understanding fully the mechanism of gas and cyst production. Here we report investigations into the composition of gas in the globes of normal fish, fish in which intraocular cysts have been documented previously by ultrasonography and fish where post-mortem examination demonstrated both gas- and fluid-filled choroidal cysts. High levels of oxygen were demonstrated in samples of aqueous from all fish but fish with affected eyes had a statistically significantly higher partial pressure of oxygen than did fish with normal eyes.
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Williams DL, Heath MF, Wallis C. Prevalence of canine cataract: preliminary results of a cross-sectional study. Vet Ophthalmol 2004; 7:29-35. [PMID: 14738504 DOI: 10.1111/j.1463-5224.2004.00317.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE In this study 2000 dogs were examined ophthalmoscopically to determine presence of cataract. MATERIALS AND METHODS The dogs examined were predominantly from veterinary hospital populations but also from the Waltham Center For Pet Nutrition, rehoming charities and breeding kennels. Prevalence of cataract was thus determined for different age groups (year cohorts). The age at which prevalence of cataract was 50% (C50) was determined indirectly from a fitted prevalence curve. RESULTS The mean +/- standard deviation of C50 for all dogs in the study was 9.4 +/- 3.3 years. All dogs over 13.5 years were affected by some degree of lens opacity. C50 was determined for animals of different genders and different breeds. For dogs of six breeds sufficient data were available for calculation of breed-specific C50. In these dogs C50 was positively correlated with longevity with a least squares correlation coefficient of 0.74. CONCLUSION The study yields novel findings regarding the prevalence and incidence of cataract in the dog and forms the basis for considerable further work on the epidemiology and pathophysiology of age-related cataract in the dog.
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Williams DL, Bowers RR, Bartness TJ, Kaplan JM, Grill HJ. Brainstem melanocortin 3/4 receptor stimulation increases uncoupling protein gene expression in brown fat. Endocrinology 2003; 144:4692-7. [PMID: 12960080 DOI: 10.1210/en.2003-0440] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Central administration of melanocortin 3 and 4 receptor (MC3/4-R) agonists increases energy expenditure, with the hypothalamus commonly held as the primary site of action. It is also clear, however, that MC4-R are expressed in caudal brainstem structures of relevance to the control of energy expenditure. Three experiments investigated whether hindbrain MC-R contribute to the energy expenditure effects of central MC3/4-R agonist treatments; in each, we examined the effect of fourth intracerebroventricular (i.c.v.) administration of a MC3/4-R agonist, MTII (three injections, each separated by 12 h), on uncoupling protein 1 (UCP-1) gene expression in brown adipose tissue (BAT). First, we compared the effects of fourth and third i.c.v. administration of MTII and found that the hindbrain and forebrain treatments were equally effective at elevating UCP-1 mRNA expression in BAT compared with the respective vehicle-treated group results. A second experiment demonstrated that the fourth i.c.v. MTII-induced rise in UCP-1 expression was mediated by sympathetic outflow to BAT by showing that this response was abolished by surgical denervation of BAT. In the third experiment, we showed that chronic decerebrate rats, like their neurologically intact controls, elevated UCP-1 mRNA expression in response to fourth i.c.v. MTII administration. Taken together, the results indicate that: 1) there is an independent caudal brainstem MC3/4-R trigger for a sympathetically stimulated elevation in BAT UCP-1 gene expression, and 2) the MTII-induced rise in UCP-1 expression can be mediated by circuitry intrinsic to the caudal brainstem and spinal cord.
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MESH Headings
- Adipose Tissue, Brown/innervation
- Adipose Tissue, Brown/physiology
- Animals
- Brain Stem/metabolism
- Carrier Proteins/genetics
- Decerebrate State/metabolism
- Energy Metabolism/drug effects
- Energy Metabolism/physiology
- Gene Expression/physiology
- Injections, Intraventricular
- Ion Channels
- Male
- Membrane Proteins/genetics
- Mitochondrial Proteins
- Peptides, Cyclic/administration & dosage
- Prosencephalon/metabolism
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptor, Melanocortin, Type 3/drug effects
- Receptor, Melanocortin, Type 3/physiology
- Receptor, Melanocortin, Type 4/drug effects
- Receptor, Melanocortin, Type 4/physiology
- Rhombencephalon/metabolism
- Sympathetic Nervous System/physiology
- Uncoupling Protein 1
- alpha-MSH/administration & dosage
- alpha-MSH/analogs & derivatives
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Williams DL. Fees for RCVS members retired ... and new. Vet Rec 2003; 152:604. [PMID: 12762497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
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Abstract
Twenty eyes of 10 dogs with keratoconjunctivitis sicca (KCS) were treated by occlusion of the ventral nasolacrimal punctum with a silicone punctal plug in order to increase the volume of the remaining tear lake. Punctal size was measured using a commercially available punctal gauge and the appropriate sized plug was inserted under local anaesthesia. Seven dogs showed an increase in Schirmer tear test I (STT) value. STT values immediately prior to plug placement were 2.3 +/- 1.7 mm/minute. STT values with punctal occlusion were 6.1 +/- 4.1 mm/minute, giving a mean increase of 3.8 +/- 2.7 mm/minute (P<0.001). In 14 eyes of eight dogs, the increase in STT values was accompanied by a clinical improvement in the appearance of the ocular surface. In the three dogs with no increase in STT values, the use of punctal plugs reduced the frequency of artificial tear replacement therapy required to maintain a healthy ocular surface. These results show that use of punctal plugs in dogs with KCS may be appropriate where other lacrimomimetic medications have been unsuccessful.
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Burnett D, Blair C, Haeney MR, Jeffcoate SL, Scott KWM, Williams DL. Clinical pathology accreditation: standards for the medical laboratory. J Clin Pathol 2002; 55:729-33. [PMID: 12354795 PMCID: PMC1769782 DOI: 10.1136/jcp.55.10.729] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
This article describes a new set of revised standards for the medical laboratory, which have been produced by Clinical Pathology Accreditation (UK) Ltd (CPA). The original standards have been in use since 1992 and it was recognised that extensive revision was required. A standards revision group was established by CPA and this group used several international standards as source references, so that the resulting new standards are compatible with the most recent international reference sources. The aim is to make the assessment of medical laboratories as objective as possible in the future. CPA plans to introduce these standards in the UK in 2003 following extensive consultation with professional bodies, piloting in selected laboratories, and training of assessors.
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de La Llera-Moya M, Connelly MA, Drazul D, Klein SM, Favari E, Yancey PG, Williams DL, Rothblat GH. Scavenger receptor class B type I affects cholesterol homeostasis by magnifying cholesterol flux between cells and HDL. J Lipid Res 2001; 42:1969-78. [PMID: 11734569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
Results from several laboratories clearly indicate that expression of scavenger receptor class B type I (SR-BI) enhances the bidirectional flux of cholesterol between cells and lipoproteins. Because the activity of HMG-CoA reductase, the key enzyme in cholesterol biosynthesis, is regulated by cell cholesterol content, we designed experiments to investigate the effect of SR-BI expression on the activity of this enzyme and on net cellular cholesterol mass. In addition, we compared the function of SR-BI with its human homolog, CD36 and LIMPII analogous 1. Our experiments demonstrate that both receptors enhance the flux of unesterified or free cholesterol bidirectionally, down a concentration gradient. Receptor-mediated cholesterol flux can effectively modulate multiple aspects of cellular cholesterol metabolism, including the pool that regulates the activity of HMG-CoA reductase. We also found that constitutive expression of SR-BI alters the steady state level of cellular cholesterol and phospholipid when SR-BI-expressing cells are maintained in medium containing serum lipoproteins. All of these effects are proportional to the level of receptor on the cell surface. These data indicate that the level of SR-BI expression determines both the rate of free cholesterol flux and the steady state level of cellular cholesterol.
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Thuahnai ST, Lund-Katz S, Williams DL, Phillips MC. Scavenger receptor class B, type I-mediated uptake of various lipids into cells. Influence of the nature of the donor particle interaction with the receptor. J Biol Chem 2001; 276:43801-8. [PMID: 11564739 DOI: 10.1074/jbc.m106695200] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Scavenger receptor (SR)-BI is the first molecularly defined receptor for high density lipoprotein (HDL) and it can mediate the selective uptake of cholesteryl ester into cells. To elucidate the molecular mechanisms by which SR-BI facilitates lipid uptake, we examined the connection between lipid donor particle binding and lipid uptake using kidney COS-7 cells transiently transfected with SR-BI. We systematically compared the uptake of [(3)H]cholesteryl oleoyl ether (CE) and [(14)C]sphingomyelin (SM) from apolipoprotein (apo) A-I-containing reconstituted HDL (rHDL) particles and apo-free lipid donor particles. Although both types of lipid donor could bind to SR-BI, only apo-containing lipid donors exhibited preferential delivery of CE over SM (i.e. nonstoichiometric lipid uptake). In contrast, apo-free lipid donor particles (phospholipid unilamellar vesicles, lipid emulsion particles) gave rise to stoichiometric lipid uptake due to interaction with SR-BI. This apparent whole particle uptake was not due to endocytosis, but rather fusion of the lipid components of the lipid donor with the cell plasma membrane; this process is perhaps mediated by a fusogenic motif in the extracellular domain of SR-BI. The interaction of apoA-I with SR-BI not only prevents fusion of the lipid donor with the plasma membrane but also allows the optimal selective lipid uptake. A comparison of rHDL particles containing apoA-I and apoE-3 showed that while both particles bound equally well to SR-BI, the apoA-I particle gave approximately 2-fold greater CE selective uptake. Catabolism of all major HDL lipids can occur via SR-BI with the relative selective uptake rate constants for CE, free cholesterol, triglycerides (triolein), and phosphatidylcholine being 1, 1.6, 0.7, and 0.2, respectively. It follows that a putative nonpolar channel created by SR-BI between the bound HDL particle and the cell plasma membrane is better able to accommodate the uptake of neutral lipids (e.g. cholesterol) relative to polar phospholipids.
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Liu Q, Guan XM, Martin WJ, McDonald TP, Clements MK, Jiang Q, Zeng Z, Jacobson M, Williams DL, Yu H, Bomford D, Figueroa D, Mallee J, Wang R, Evans J, Gould R, Austin CP. Identification and characterization of novel mammalian neuropeptide FF-like peptides that attenuate morphine-induced antinociception. J Biol Chem 2001; 276:36961-9. [PMID: 11481330 DOI: 10.1074/jbc.m105308200] [Citation(s) in RCA: 217] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The two mammalian neuropeptides NPFF and NPAF have been shown to have important roles in nociception, anxiety, learning and memory, and cardiovascular reflex. Two receptors (FF1 and FF2) have been molecularly identified for NPFF and NPAF. We have now characterized a novel gene designated NPVF that encodes two neuropeptides highly similar to NPFF. NPVF mRNA was detected specifically in a region between the dorsomedial and ventromedial hypothalamic nuclei. NPVF-derived peptides displayed higher affinity for FF1 than NPFF-derived peptides, but showed poor agonist activity for FF2. Following intracerebral ventricular administration, a NPVF-derived peptide blocked morphine-induced analgesia more potently than NPFF in both acute and inflammatory models of pain. In situ hybridization analysis revealed distinct expression patterns of FF1 and FF2 in the rat central nervous system. FF1 was broadly distributed, with the highest levels found in specific regions of the limbic system and the brainstem where NPVF-producing neurons were shown to project. FF2, in contrast, was mostly expressed in the spinal cord and some regions of the thalamus. These results indicate that the endogenous ligands for FF1 and FF2 are NPVF- and NPFF-derived peptides, respectively, and suggest that the NPVF/FF1 system may be an important part of endogenous anti-opioid mechanism.
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47
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Butler AR, Elkins-Daukes S, Parkin D, Williams DL. Direct NO group transfer from S-nitrosothiols to iron centres. Chem Commun (Camb) 2001:1732-3. [PMID: 12240288 DOI: 10.1039/b105460k] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A number of S-nitrosothiols react rapidly with the Fe(II) complexes of 2,3-dimercapto-1-propanesulfonic acid (DMPS) and of N-methyl-D-glucamine dithiocarbamate (MGD), transferring the NO group directly to the iron centres.
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48
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Lowman DW, Williams DL. A proton nuclear magnetic resonance method for the quantitative analysis on a dry weight basis of (1-->3)-beta-D-glucans in a complex, solvent-wet matrix. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2001; 49:4188-4191. [PMID: 11559108 DOI: 10.1021/jf010435l] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Health benefits of the polysaccharide (1-->3)-beta-D-glucan, reported to induce immunobiological, hypocholesterolemic, and hypoglycemic effects in humans and animals, have made the isolation, characterization, and assay of a viable glucan product critical. A new analytical method, based on internal standard proton NMR analysis, for the assay of solvent-wet samples containing (1-->3)-beta-D-glucan is presented. The method enables glucan identification, provides a solvent-free assay, and improves upon the previous multistep extraction and lyophilization procedure by reducing the 1-2 day analysis time to 1-2 h. NMR offers a rapid method for quantifying the glucan in commercial samples, such as nutraceuticals, as well as industrial samples enabling better evaluation of the efficacy of these carbohydrates in health-related applications.
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49
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Ahrén IL, Williams DL, Rice PJ, Forsgren A, Riesbeck K. The importance of a beta-glucan receptor in the nonopsonic entry of nontypeable Haemophilus influenzae into human monocytic and epithelial cells. J Infect Dis 2001; 184:150-8. [PMID: 11424011 DOI: 10.1086/322016] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2000] [Revised: 04/18/2001] [Indexed: 11/03/2022] Open
Abstract
Previous reports showed that nontypeable Haemophilus influenzae (NTHi) reside in macrophage-like cells in human adenoid tissue. This study investigated the ability of nonopsonized NTHi and encapsulated H. influenzae type b (Hib) to enter human monocytic and epithelial cells. The number of intracellular bacteria was determined by a viability assay and flow cytometry. To characterize the mechanisms responsible for the internalization of NTHi, different inhibitors of surface molecules, receptor turnover, and the cytoskeleton were used. Hib were found in monocytic cells at very low numbers (<100 bacteria/2x105 cells). In contrast, a great variation in intracellular numbers was detected between the different NTHi isolates (range, 0.0007%-0.28% of the inoculum for monocytes and 0.053%-3.5% for epithelial cells). NTHi entered human monocytic and epithelial cells via a receptor-mediated endocytosis involving mainly a beta-glucan receptor that could be blocked by laminarin.
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50
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Thomas GA, Williams DL, Soper SA. Capillary electrophoresis-based heteroduplex analysis with a universal heteroduplex generator for detection of point mutations associated with rifampin resistance in tuberculosis. Clin Chem 2001; 47:1195-203. [PMID: 11427449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
BACKGROUND Slab gel heteroduplex analysis (HDA), a popular scanning method for genetic mutations, uses DNA fragments typically generated by PCR to create homo- and heteroduplex molecules with conformational differences and sequence-dependent electrophoretic profiles. Use of a universal heteroduplex generator (UHG) enhances the subtle variations caused by single-base substitutions. METHODS The HDA-UHG slab gel format was modified for an efficient capillary-based method. The effect of staining dyes TOPRO5 and YOPRO1 on the analysis of heteroduplexes was studied, as well as ultraviolet absorbance and laser-induced fluorescence (LIF) detection methods. In addition, the entangled polymers hydroxyethyl cellulose, methyl cellulose, and linear polyacrylamide were evaluated as separation matrices. RESULTS This assay was able to detect the presence of Mycobacterium tuberculosis and its rifampin susceptibility directly from clinical specimens in dramatically reduced analysis time (30 min vs 2.5 h). Optimized conditions included 0.3% methyl cellulose as the separation matrix, on-line staining using 1 micromol/L YOPRO1, and LIF detection for quantitative and reproducible analysis of single-base substitutions in the rifampin resistance-determining region of rpoB that give rise to the rifampin-resistant phenotype of M. tuberculosis. We generated 95% confidence limits using the wild-type sequence and used these limits to determine rifampin susceptibility in samples. CONCLUSIONS Capillary electrophoresis, combined with the HDA-UHG technique, may be of value for rapid and efficient clinical diagnosis of rifampin-resistant tuberculosis strains.
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