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1.
Nat Med ; 3(5): 533-40, 1997 May.
Artigo em Inglês | MEDLINE | ID: mdl-9142122

RESUMO

Changes in CD4+ T-cell surface marker phenotype and antigen receptor (TCR) repertoire were examined during the course of HIV infection and following therapy. A preferential decline in naive CD4+ T cells was noted as disease progressed. Following protease inhibitor therapy, naive CD4+ T cells increased only if they were present before initiation of therapy. Disruptions of the CD4+ TCR repertoire were most prevalent in patients with the lowest CD4+ T-cell counts. Antiviral or IL-12 therapy-induced increases in CD4+ T-cell counts led to only minor changes in previously disrupted repertoires. Thus, CD4+ T-cell death mediated by HIV-1 infection may result in a preferential decline in the number of naive CD4+ T cells and disruptions of the CD4+ T-cell repertoire that are not immediately corrected by antiviral or immune-based therapies.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Infecções por HIV/imunologia , Inibidores da Protease de HIV/uso terapêutico , Indinavir/uso terapêutico , Interleucina-2/uso terapêutico , Progressão da Doença , Infecções por HIV/tratamento farmacológico , Humanos , Antígenos Comuns de Leucócito/sangue , Fenótipo , RNA Mensageiro/sangue , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Gêmeos Monozigóticos
2.
Nat Med ; 4(7): 852-6, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9662381

RESUMO

The CD4+ T-cell pool in HIV-infected patients is in a constant state of flux as CD4+ T cells are infected and destroyed by HIV and new cells take their place. To study T-cell survival, we adoptively transferred peripheral blood lymphocytes transduced with the neomycin phosphotransferase gene between syngeneic twin pairs discordant for HIV infection. A stable fraction of marked CD4+ T cells persisted in the circulation for four to eighteen weeks after transfer in all patients. After this time there was a precipitous decline in marked cells in three of the patients. At approximately six months, marked cells were in lymphoid tissues in proportions comparable to those found in peripheral blood. In two patients, the proportion of total signal for the transgene (found by PCR analysis) in the CD4/CD45RA+ T-cell population relative to the CD4/CD45RO+ population increased in the weeks after cell infusion. These findings indicate that genetically-marked CD4+ T cells persist in vivo for weeks to months and that the CD4+ T-cell pool in adults is maintained mostly by the division of mature T cells rather than by differentiation of prethymic stem cells. Thus, after elements of the T-cell repertoire are lost through HIV infection, they may be difficult to replace.


Assuntos
Linfócitos T CD4-Positivos/fisiologia , Infecções por HIV/imunologia , Linfócitos T/fisiologia , Adulto , Linfócitos T CD4-Positivos/imunologia , Infecções por HIV/fisiopatologia , Humanos , Antígenos Comuns de Leucócito/imunologia , Leucopoese , Masculino , Fosfotransferases/genética , Fosfotransferases/metabolismo , Regeneração
3.
J Dev Orig Health Dis ; 10(4): 387-405, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30411697

RESUMO

Despite many interventions aiming to reduce excessive gestational weight gain (GWG), it is currently unclear the impact on infant anthropometric outcomes. The aim of this review was to evaluate offspring anthropometric outcomes in studies designed to reduce GWG. A systematic search of seven international databases, one clinical trial registry and three Chinese databases was conducted without date limits. Studies were categorised by intervention type: diet, physical activity (PA), lifestyle (diet + PA), other, gestational diabetes mellitus (GDM) (diet, PA, lifestyle, metformin and other). Meta-analyses were reported as weighted mean difference (WMD) for birthweight and birth length, and risk ratio (RR) for small for gestational age (SGA), large for gestational age (LGA), macrosomia and low birth weight (LBW). Collectively, interventions reduced birthweight, risk of macrosomia and LGA by 71 g (WMD: -70.67, 95% CI -101.90 to -39.43, P<0.001), 16% (RR: 0.84, 95% CI 0.73-0.98, P=0.026) and 19% (RR: 0.81, 95% CI 0.69-0.96, P=0.015), respectively. Diet interventions decreased birthweight and LGA by 99 g (WMD -98.80, 95% CI -178.85 to -18.76, P=0.016) and 65% (RR: 0.35, 95% CI 0.17-0.72, P=0.004). PA interventions reduced the risk of macrosomia by 51% (RR: 0.49, 95% CI 0.26-0.92, P=0.036). In women with GDM, diet and lifestyle interventions reduced birthweight by 211 and 296 g, respectively (WMD: -210.93, 95% CI -374.77 to -46.71, P=0.012 and WMD:-295.93, 95% CI -501.76 to -90.10, P=0.005, respectively). Interventions designed to reduce excessive GWG lead to a small reduction in infant birthweight and risk of macrosomia and LGA, without influencing the risk of adverse outcomes including LBW and SGA.


Assuntos
Peso ao Nascer , Macrossomia Fetal/prevenção & controle , Ganho de Peso na Gestação/fisiologia , Fenômenos Fisiológicos da Nutrição Materna , Sobrepeso/fisiopatologia , Aumento de Peso/fisiologia , Dieta , Exercício Físico , Feminino , Macrossomia Fetal/patologia , Humanos , Recém-Nascido , Estilo de Vida , Gravidez
4.
Eur J Clin Nutr ; 70(3): 292-9, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26603882

RESUMO

BACKGROUND/OBJECTIVES: Intermittent energy restriction (IER) is an eating pattern of regular daily periods of restricted energy intake followed by periods of unrestricted energy intake. This is gaining prominence as an alternative weight-loss strategy to daily energy restriction (DER). The aim of this systematic review was to determine the effectiveness of IER on weight loss in overweight and obese adults and compare this with DER. SUBJECTS/METHODS: A systematic literature search was conducted using the CINAHL, Embase, Medline, PsycINFO, Cochrane and Scopus databases. Eight studies that assigned overweight or obese adults to IER or to a DER 'control' were deemed eligible for inclusion. RESULTS: All studies reported significant weight loss for IER groups. Average weight loss was approximately 0.2-0.8 kg per week. IER resulted in comparable weight loss to DER when overall energy restriction remained similar between diets. The majority of studies that reported body composition outcomes have shown equal efficacy for fat mass, fat-free mass and waist circumference. CONCLUSIONS: Weight loss was achieved in overweight and obese adults following IER and this loss was comparable to a DER diet. IER may be an effective alternative strategy for health practitioners to promote weight loss for selected overweight and obese people.


Assuntos
Restrição Calórica , Dieta Redutora , Obesidade/dietoterapia , Sobrepeso/dietoterapia , Redução de Peso , Composição Corporal , Humanos , Metanálise como Assunto , Cooperação do Paciente , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do Tratamento , Circunferência da Cintura
5.
Bone ; 83: 9-16, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26456145

RESUMO

Methods currently used to analyse osteolytic lesions caused by malignancies such as multiple myeloma and metastatic breast cancer vary from basic 2-D X-ray analysis to 2-D images of micro-CT datasets analysed with non-specialised image software such as ImageJ. However, these methods have significant limitations. They do not capture 3-D data, they are time-consuming and they often suffer from inter-user variability. We therefore sought to develop a rapid and reproducible method to analyse 3-D osteolytic lesions in mice with cancer-induced bone disease. To this end, we have developed Osteolytica, an image analysis software method featuring an easy to use, step-by-step interface to measure lytic bone lesions. Osteolytica utilises novel graphics card acceleration (parallel computing) and 3-D rendering to provide rapid reconstruction and analysis of osteolytic lesions. To evaluate the use of Osteolytica we analysed tibial micro-CT datasets from murine models of cancer-induced bone disease and compared the results to those obtained using a standard ImageJ analysis method. Firstly, to assess inter-user variability we deployed four independent researchers to analyse tibial datasets from the U266-NSG murine model of myeloma. Using ImageJ, inter-user variability between the bones was substantial (±19.6%), in contrast to using Osteolytica, which demonstrated minimal variability (±0.5%). Secondly, tibial datasets from U266-bearing NSG mice or BALB/c mice injected with the metastatic breast cancer cell line 4T1 were compared to tibial datasets from aged and sex-matched non-tumour control mice. Analyses by both Osteolytica and ImageJ showed significant increases in bone lesion area in tumour-bearing mice compared to control mice. These results confirm that Osteolytica performs as well as the current 2-D ImageJ osteolytic lesion analysis method. However, Osteolytica is advantageous in that it analyses over the entirety of the bone volume (as opposed to selected 2-D images), it is a more rapid method and it has less user variability.


Assuntos
Processamento de Imagem Assistida por Computador , Neoplasias/complicações , Osteólise/diagnóstico por imagem , Osteólise/etiologia , Software , Animais , Automação , Neoplasias da Mama/complicações , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , Neoplasias/patologia , Reprodutibilidade dos Testes , Interface Usuário-Computador , Microtomografia por Raio-X
6.
Diabetes ; 44(4): 446-52, 1995 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-7698515

RESUMO

In many tissues, hyperglycemia alters the activities of the Na(+)-dependent myo-inositol (Na/MI) transporter, Na(+)-K(+)-ATPase, and protein kinase C (PKC). However, little is known concerning adaptive changes in renal proximal tubular function after acute or chronic hyperglycemia. We examined hyperglycemia-induced changes in Na/MI transport, Na(+)-K(+)-ATPase activity, and PKC activity using three proximal tubule-like cell lines (JTC12, LLC-PK1, and OK/E cells) and primary cultures of human proximal tubular epithelium (HK cells) cultured for varying periods in low- or high-glucose media, myo-Inositol (MI) transport was mediated by a high-affinity (Km approximately 50 mumol/l) Na(+)-dependent saturable process in the four cell lines. Hyperglycemia produced a time-dependent and persistent increase in Na/MI transport in all cell lines. Chronic hyperglycemia increased the Km for MI transport in LLC-PK1 cells and increased the Vmax in both LLC-PK1 and JTC12 cells. Glucose competitively inhibited Na/MI transport in all low-glucose cells and in high-glucose HK, JTC12, and OK/E cells but had no effect on transport in high-glucose LLC-PK1 cells. Acute hyperglycemia also produced time-dependent increases in Na(+)-K(+)-ATPase activity in all cell lines, a change that persisted only in HK cells. A 24-h exposure to high glucose had no effect on PKC activity in any of the cell lines but increased Ca/phospholipid-dependent PKC activity in membrane fractions from chronically high-glucose LLC-PK1 and OK/E cells. These data suggest that hyperglycemia causes acute changes in proximal tubule function and long-lived adaptive responses in Na/MI transport and the PKC signaling pathway.


Assuntos
Hiperglicemia/metabolismo , Inositol/metabolismo , Túbulos Renais Proximais/metabolismo , Proteína Quinase C/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Sódio/metabolismo , Transporte Biológico , Membrana Celular/enzimologia , Células Cultivadas , Citosol/enzimologia , Humanos , Técnicas In Vitro , Fatores de Tempo
7.
Arch Intern Med ; 157(4): 433-8, 1997 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-9046895

RESUMO

OBJECTIVE: To assess the long-term predictive usefulness of radiographic absorptiometry measurements of phalangeal bone density for hip fracture risk. METHODS: Participants were members of the First National Health and Nutrition Examination Survey Epidemiologic Follow Up Study cohort. Subjects were followed up for a maximum of 16 years. The First National Health and Nutrition Examination Survey data were obtained from a nationally representative sample of non-institutionalized civilians. A cohort of 3481 white and black subjects (1559 white women) aged 45 through 74 years at baseline (1971-1975) were observed through 1987. Ninety-eight percent of the original cohort completed the study. Hospital records and death certificates were used to identify a total of 72 hip fracture cases. Phalangeal bone density at baseline was measured using photodensitometry (PD), and later reanalyzed by radiographic absorptiometry (RA), a newer, more sophisticated technique. RESULTS: Results were evaluated to determine the relative risk for hip fracture per 1-SD decrease in bone density, after controlling for age at baseline, race, gender, weight, and previous fractures. Both RA and PD measurements showed a significant inverse relationship to hip fracture risk, with RA density measurements showing a slightly higher adjusted relative risk per 1-SD density decrease than PD measurements. For RA bone density, the relative risk for all subjects was 1.81 (95% confidence interval, 1.34-2.44) compared with 1.57 (95% confidence interval, 1.19-2.07) for PD bone density after adjusting for age at baseline, race, gender, weight, and previous fractures. Results for white women were essentially the same as those for all subjects for RA bone density and PD bone density. CONCLUSIONS: Phalangeal bone density determined from standard hand x-ray films is a significant predictor of future hip fracture risk. Availability of a valid method to assess fracture risk using conventional radiographs will expand the ability to identify individuals with osteoporosis.


Assuntos
Absorciometria de Fóton , Densidade Óssea , Dedos/diagnóstico por imagem , Fraturas do Quadril , Idoso , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Risco
8.
AIDS ; 14(12): 1709-15, 2000 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-10985306

RESUMO

OBJECTIVE: To compare the architecture and HIV-1 RNA and Gag p24 protein expression in lymph nodes (LN) excised from individuals during chronic highly active antiretroviral therapy (HAART) with LN removed from the same patient after plasma virus rebound following the interruption of HAART. MATERIALS AND METHODS: Six HIV-1-infected patients on HAART, with CD4 cell counts greater than 350 cells/microl, and plasma HIV-1 RNA less than 50 copies/ml, underwent inguinal LN excision upon discontinuation of HAART, and again after rebound of plasma virus. Lymph nodes were evaluated by immunohistochemical staining for Gag p24 antigen and Ki67, in-situ hybridization for HIV-1 RNA and H3-histone, and transmission electron microscopy (TEM). RESULTS: LN at baseline were quiescent to mildly hyperplastic and generally contained more primary than secondary follicles. Only one LN had detectable follicular dendritic cell (FDC)-associated p24 antigen, none had HIV RNA. Few mononuclear cells (MNC) expressed RNA or p24 antigen. Plasma virus at the second biopsy ranged from 329 to 3.2 x 10(6) copies/ml. CD4 cell count decline ranged from 5 to 51% during drug hiatus, and was greatest in patients with highest viral rebound. Four of six of the second LN were more hyperplastic than the initial LN, two showed paracortical hyperplasia. MNC expression of HIV RNA in the second LN paralleled the level of plasma viremia. Increased Ki67 and H3-histone signal occurred in the second LN. CONCLUSION: Quiescent LN from individuals on HAART rapidly become hyperplastic and activated within 1-2 months after treatment interruption. As in acute HIV infection, virus expression by LN MNC parallels the rebound in plasma viremia and fall in CD4 cell count.


Assuntos
Terapia Antirretroviral de Alta Atividade , Infecções por HIV/tratamento farmacológico , HIV-1/fisiologia , Linfonodos/virologia , Contagem de Linfócito CD4 , Proteína do Núcleo p24 do HIV/análise , Proteína do Núcleo p24 do HIV/sangue , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , Humanos , Imuno-Histoquímica , Hibridização In Situ , Linfonodos/efeitos dos fármacos , Linfonodos/patologia , Microscopia Eletrônica , RNA Viral/análise , RNA Viral/sangue , Carga Viral , Viremia/virologia
9.
AIDS ; 13(16): 2219-29, 1999 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-10563707

RESUMO

OBJECTIVES: To evaluate changes in architecture, viral RNA, and viral protein over 6 months in lymph nodes from retroviral-naïve HIV-infected persons before and after commencing highly active antiretroviral therapy (HAART). METHODS: Nine antiretroviral-naïve HIV-infected persons had lymph nodes excised at baseline and at 2 and 6-8 months after beginning a four-drug combination regimen containing zidovudine, lamivudine, nevirapine, and indinavir. Two patients had AIDS. Lymph nodes were examined by immunohistochemical staining for Gag p24 HIV, CD3, CD21, CD20, HAM 56, and Ki67 antigens and by in-situ hybridization (ISH) for HIV RNA and H3-histone RNA. RESULTS: Eight of nine baseline lymph nodes showed follicular hyperplasia and germinal center and paracortical mononuclear cell activation. At 2 months, the lymph nodes from seven patients, including the AIDS patients, showed more follicular hyperplasia and activation than their baseline specimens but with decreased mononuclear cell activation. By 6 months, seven lymph nodes were less hyperplastic and activated than their corresponding 2 month specimens. Combined ISH/immunohistochemical staining of baseline lymph nodes revealed productively infected T (CD3) and B (CD20) cells and macrophages (HAM56+). HIV RNA-positive mononuclear cells were infrequent at 2 months, and rare at 6 months. HIV RNA was still associated with follicular dendritic cells (FDC) at 2 months, but not at 6 months. HIV p24-positive antigen in germinal centers persisted through all 6, and the one 8 month specimens. The baseline lymph nodes from one of the AIDS patients was involuted and T cell depleted, whereas the follow-up lymph nodes were hyperplastic with normal T cell levels. CONCLUSION: Follicular hyperplasia and cell activation, possibly caused by persistent viral protein in germinal centers, may help explain why HIV viremia rebounds so rapidly after the interruption of HAART. Restoration of architecture may follow the treatment of patients with AIDS who initially had involuted and CD4 cell-depleted lymph nodes.


Assuntos
Síndrome da Imunodeficiência Adquirida/patologia , Fármacos Anti-HIV/uso terapêutico , Contagem de Linfócito CD4 , Proteína do Núcleo p24 do HIV/sangue , Linfonodos/patologia , Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Infecções por HIV/tratamento farmacológico , Infecções por HIV/patologia , Humanos , Depleção Linfocítica , Microscopia Eletrônica , Carga Viral
10.
Am J Med ; 84(3 Pt 2): 640-2, 1988 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-3348274

RESUMO

In two patients with the acquired immunodeficiency syndrome (AIDS), multiple erythematous cutaneous lesions developed, revealing acid-fast organisms on Fite's stain. Initial culture results on the first patient were negative; however, repeat cultures on hemin-enriched media were positive for Mycobacterium haemophilum. Despite antimycobacterial therapy, lesions persisted until the patients' death. M. haemophilum should be a diagnostic consideration when smears of peripheral (especially skin) lesions from AIDS patients show acid-fast organisms. Cultures in such patients should be done with iron hemin- or ferric ammonium citrate-enriched media.


Assuntos
Síndrome da Imunodeficiência Adquirida/complicações , Infecções por Mycobacterium não Tuberculosas/etiologia , Infecções por Mycobacterium/etiologia , Dermatopatias Infecciosas/etiologia , Adulto , Humanos , Masculino , Micobactérias não Tuberculosas/isolamento & purificação
11.
Autoimmunity ; 19(1): 1-5, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-7749037

RESUMO

We studied a large North American Caucasian population of patients with biopsy proven IgA nephropathy for polymorphisms of HLA-A,B,C, HLA-DR, HLA-DQ and HLA-DP using a combination of serologic phenotyping and polymerase chain reaction sequence specific oligonucleotide probe (PCR-SSOP) hybridization genotyping. We also examined patients for polymorphisms of immunoglobulin by determining Gm and Km allotypes. When compared to healthy local controls there was an apparent decrease in HLA-DR5 (DRw11, DRw12) suggesting that this allele had a protective effect on disease susceptibility. None of the previously reported HLA-DQ associations found among Japanese or british Caucasian patients were found among this large North American Caucasian population. The HLA-DPB1*0601 genotype was increased among patients, but this was not significant when corrected for multiple comparisons. There were no differences in the distribution of Gm or Km allotypes among patients versus controls, regardless of whether they were stratified into those with progressive or non-progressive renal disease. Taken together, these findings suggest that there is substantial genetics heterogeneity in susceptibility to IgA nephropathy among different ethnic and/or geographically distinct populations.


Assuntos
Genes de Imunoglobulinas , Genes MHC da Classe II , Genes MHC Classe I , Glomerulonefrite por IGA/genética , Antígenos HLA/genética , Imunoglobulina A/genética , Alótipos de Imunoglobulina/genética , Alelos , Estudos de Casos e Controles , Frequência do Gene , Predisposição Genética para Doença , Glomerulonefrite por IGA/etnologia , Glomerulonefrite por IGA/imunologia , Antígeno HLA-DR5/genética , Teste de Histocompatibilidade , Humanos , Alótipos Gm de Imunoglobulina/genética , Cadeias Leves de Imunoglobulina , Reação em Cadeia da Polimerase , População Branca/genética
12.
Pharmacotherapy ; 19(9): 1050-6, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10610011

RESUMO

STUDY OBJECTIVE: To evaluate the pharmacokinetics and safety of atovaquone suspension in volunteers infected with the human immunodeficiency virus ((HIV). DESIGN: Open-label, nonrandomized study. SETTING: Two clinical research centers. PATIENTS: Twenty-two HIV-infected volunteers with a median CD4 cell count of 37 cells/mm3. INTERVENTIONS: Patients received atovaquone suspension fasting or fed for 2-week periods with crossover at dosages of 500 mg/day, and randomization to fasting or fed at dosages of 750 and 1000 mg/day. A subset of patients also received 750 mg twice/day with food, and a subset of those who received 1000 mg/day fasting also received 1000 mg with food. During a long-term dosing phase, a subset of subjects were evaluated for an interaction between atovaquone and trimethoprim-sulfamethoxazole (TMP-SMX). MEASUREMENTS AND MAIN RESULTS: Average steady-state atovaquone concentrations at 500 mg were 6.7 +/- 3.2 microg/ml fasted and 11.3 +/- 5.0 microg/ml with food; at 750 mg, 9.9 +/- 7.1 microg/ml fasted and 12.5 +/- 5.9 microg/ml with food; at 1000 mg, 9.7 +/- 4.3 microg/ml fasted and 13.6 +/- 5.0 microg/ml with food; and at 1500 mg, 21.1 +/- 5.0 microg/ml with food. Thus, plasma concentrations were not proportional to dose. Concomitant food ingestion resulted in a 1.3- to 1.7-fold increase in values. Average steady-state concentrations were less than 10 microg/ml in 21% and more than 15 microg/ml in 36% of patients at 1000 mg/day with food; at 750 mg twice/day, all five patients had levels above 15 microg/ml. Atovaquone suspension was well tolerated; diarrhea, nausea, fatigue, and rash were the most common adverse events. Concomitant administration of TMP-SMX did not change atovaquone concentrations and resulted in small decreases in concentrations of TMP (16%) and SMX (10%). CONCLUSION: Plasma concentrations are significantly higher when atovaquone suspension is administered with food compared with fasting. Total doses of 1500 mg/day are likely to achieve concentrations effective for prophylaxis of Pneumocystis carinii pneumonia.


Assuntos
Antifúngicos/efeitos adversos , Antifúngicos/farmacocinética , Naftoquinonas/efeitos adversos , Naftoquinonas/farmacocinética , Infecções Oportunistas Relacionadas com a AIDS/metabolismo , Infecções Oportunistas Relacionadas com a AIDS/prevenção & controle , Adulto , Antifúngicos/administração & dosagem , Atovaquona , Jejum , Feminino , Interações Alimento-Droga , Humanos , Masculino , Pessoa de Meia-Idade , Naftoquinonas/administração & dosagem , Pneumonia por Pneumocystis/prevenção & controle , Combinação Trimetoprima e Sulfametoxazol/farmacocinética
13.
Am J Hum Biol ; 10(6): 689-697, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-28561406

RESUMO

Despite the fact that skinfold calipers are widely used to measure subcutaneous adipose tissue, the current methods of calibration are quite crude. Methods such as hanging masses from the caliper jaws until they remain open, lack validity and reliability because the caliper jaws are stationary instead of dynamic, and the opening jaws give an upscale reading of the jaw gap not a downscale reading that occurs when the calipers are being used to measure skinfolds. This report describes how to build an apparatus capable of measuring static and dynamic, upscale and downscale jaw pressures of a variety of caliper types and also provides guidelines specifically for calibration and servicing of Harpenden calipers. The key areas to maintain are the caliper springs (which should have spring coefficients ranging 1.104-1.153 N.mm-1 ), the pivot joint (which should operate smoothly), the indicator mechanism (which should require only 0.78-0.88 N for full movement), and the jaw alignment which should be square to ensure that the full effective jaw surface area of 90 mm2 is applied to the skinfold. While there are insufficient data at this time to prescribe rigid calibration criteria, assessment of approximately 100 new and used Harpenden calipers indicates that, after servicing, the important dynamic downscale jaw pressure will range 7.7-8.4 g.mm-2 at 5 mm of jaw gap and 7.3-8.0 g.mm-2 at 40 mm of jaw gap. Dynamic upscale jaw pressure should be within 1.0-1.5 g.mm-2 of the corresponding dynamic downscale jaw pressure. Am. J. Hum. Biol. 10:689-697, 1998. © 1998 Wiley-Liss, Inc.

14.
J Am Vet Med Assoc ; 214(8): 1212-7, 1999 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-10212686

RESUMO

OBJECTIVE: To evaluate the breeding soundness examination procedure in plains bison bulls. DESIGN: Multiyear (1993 through 1997) cross-sectional clinical procedure evaluation. ANIMALS: Two hundred thirty-four 28- to 30-month-old bison bulls at Custer State Park. PROCEDURE: Breeding soundness examinations were performed on all bison bulls using 1992 Society for Theriogenology guidelines for beef cattle semen evaluation and reproductive tract examination. Linear and logistic regression analyses were used to detect correlations and associations among breeding soundness examination variables. RESULTS: Scrotal circumference (SC) was significantly correlated with body weight, percentage of normal spermatozoa, percentage of primary spermatozoal defects, and percentage of motile spermatozoa. Scrotal circumference was positively associated with increased odds of semen collection, satisfactory motility (> or = 30% motility), satisfactory morphology (> or = 70% normal spermatozoa), and simultaneous satisfactory motility and morphology. Receiver-operator characteristic curve analysis selected 29 cm as the optimal SC cutoff most predictive of simultaneous satisfactory spermatozoal motility and morphology. Only 36.2% (83/229) of the bison bulls had a SC of 29 cm or greater and satisfactory spermatozoal motility and morphology. CLINICAL IMPLICATIONS: SC is a good indicator of adequate spermatozoal motility and structure in bison. We recommend use of 30% spermatozoal motility, 70% normal spermatozoal morphology, and 29-cm SC as minimal satisfactory measurements for breeding soundness examinations of 28- to 30-month-old bison bulls that have been raised on forage-based nutrition.


Assuntos
Bison/anatomia & histologia , Bison/fisiologia , Cruzamento , Animais , Peso Corporal , Intervalos de Confiança , Estudos Transversais , Genitália Masculina/anatomia & histologia , Modelos Lineares , Modelos Logísticos , Masculino , Razão de Chances , Exame Físico/veterinária , Curva ROC , Escroto/anatomia & histologia , Sêmen/citologia , Sêmen/fisiologia , Motilidade dos Espermatozoides , Espermatozoides/ultraestrutura
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