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Biomedical subjects

D L Miller

Publications and source records attributed to D L Miller.

At least 19 recordsLinked to original sources

Feline immunodeficiency virus and puma lentivirus in Florida panthers (Puma concolor coryi): epidemiology and diagnostic issues.

This study documents the seroprevalence of feline immunodeficiency virus (FIV) and puma lentivirus (PLV) in free-ranging and captive Florida panthers (Puma concolor coryi) (n = 51) and translocated Texas cougars (P. concolor stanleyana) (n = 10) from 1985 to 1998. The sera were tested for anti-FIV antibodies by enzyme-linked immunosorbent assay (ELISA) and Western blot tests. The ELISAs were read kinetically (KELA) and the sera were retrospectively examined by PLV peptide ELISA. Eleven panthers and one cougar were positive by KELA; 4 panthers and 4 cougars were equivocal; 35 panthers and 5 cougars were negative; and 1 panther had no data. Seven of the 11 KELA-positive panthers were also positive by Western blot tests and all but one were positive by PLV peptide ELISA. Ten KELA-negative and Western blot-negative cats, were positive by PLV peptide ELISA. KELA results varied within cats from one sample period to the next, but PLV peptide ELISA results were consistent. Territorial sympatry and mating behaviour, noted from radiotelemetry location data on the cats, may have contributed to viral transmission between seropositive animals. These findings suggest that Florida panthers and the introduced Texas cougars have been exposed to FIV and/or PLV.

Animals↗

Subcutaneous haemangiosarcoma in a cockatiel (Nymphicus hollandicus).

An ulcerated, 1 x 0.5 cm, subcutaneous mass on the craniolateral aspect of the right tibiotarsus of a 4-year-old male cockatiel was removed. Histologically, the neoplasm was non-encapsulated, infiltrative and composed of irregular vascular channels lined by branching and variably sized spindle-shaped cells with large vesicular nuclei, prominent nucleoli and rare mitoses. Surrounding these vascular channels were fibroblasts and mixed inflammatory cells. Neoplastic cells had diffuse immunoreactivity to factor VIII supporting a diagnosis of haemangiosarcoma.

Animals↗

Equine herpesvirus 2-associated granulomatous dermatitis in a horse.

Granulomatous dermatitis in horses has been linked to many etiologies, including various parasites, fungi, and bacteria. Idiopathic forms of granulomatous inflammation-producing diseases, some of which are localized to the skin, also have been reported in horses. Herein we describe a case of recurrent equine granulomatous skin disease characterized by intranuclear viral inclusions within macrophages and giant cells. The histologic changes were primarily noted in the deep dermis and included multifocal to coalescing areas of necrosis marked by histiocytic cell infiltration and presence of giant cells. Electron microscopic examination revealed intranuclear and intracytoplasmic viral particles consistent with herpesvirus. Sequence results of the polymerase chain reaction product were consistent with equine herpesvirus 2, adding another possible etiology to the list of differentials in cases of equine granulomatous skin disease.

Animals↗

Immunohistochemical expression of calretinin in canine testicular tumours and normal canine testicular tissue.

Calretinin is a calcium-binding protein expressed abundantly in the central and peripheral neural tissues. It has been demonstrated to be a valuable marker in human testicular neoplasia. The immunohistochemical expression of calretinin has been studied in 102 samples of normal (n=25) and three different neoplastic canine testicular tumours (n=77). In normal canine testis, calretinin expression was restricted to Leydig and Sertoli cells of the testis. In tumour tissues, calretinin expression was detected in all tumours investigated (interstitial cell tumours, seminoma, and Sertoli cell tumours), with a cytoplasmic and nuclear pattern of cellular distribution. The present work reports, for the first time, calretinin immunohistochemical expression in normal and neoplastic canine testis.

Animals↗

Environmental tobacco smoke exposure in women with lung cancer.

BACKGROUND: Investigations on environmental tobacco smoke (ETS) exposure that include source intensity, childhood exposure, and association with histologic subtypes among never smoking lung cancer cases are limited. We report the patterns of ETS exposure history in a clinical cohort of women with newly diagnosed lung cancer. METHODS: From 1997 to 2001, 810 women with lung cancer were interviewed to obtain data including the source, intensity, and duration of ETS exposure. In this descriptive study, relationships between smoking history, ETS exposure, and lung cancer histologic subtypes were analyzed. RESULTS: Among the 810 patients, 773 (95.4%) reported personal smoking or ETS exposure including 170 of 207 (82%) never smokers. Among the never smokers with a history of ETS exposure, the mean years of exposure were 27 from a smoking spouse, 19 from parents, and 15 from co-workers. For each major subtype of lung cancer (adenocarcinoma, squamous cell, unclassified non-small cell lung cancer, small cell, or carcinoids) among never smokers, 75-100% of patients had ETS exposure. Trends for adenocarcinoma, squamous, and small cell carcinoma are statistically significant using the Cochran-Armitage Test for Trend (P<0.001) among never smokers without ETS exposure, never smokers with ETS exposure, former smokers, and current smokers. CONCLUSIONS: Over 95% of women with lung cancer in our study were exposed to tobacco smoke through a personal smoking history or ETS. The cumulative amount of tobacco smoke exposure may be significantly underestimated if only personal smoking history is considered. Our results add to the public health implications of exposure to tobacco smoke and highlight the importance of eliminating tobacco smoking in public and private settings.

Adult↗

Metacercariae of Clinostomum attenuatum in Ambystoma tigrinum mavortium, Bufo cognatus and Spea multiplicata from west Texas.

Tissues from barred tiger salamanders (Ambystoma tigrinum mavortium), Great Plains toads (Bufo cognatus) and New Mexico spadefoots (Spea multiplicata) collected from 16 playa wetlands in Texas during 1999 and 2000 were examined by light microscopy. Digenean cysts were primarily distributed subcutaneously throughout the specimens and occasionally coelomic invasion was noted. The parasites within the cysts were 1.5-2 mm in diameter, with a thin (c. 10 microm wide) eosinophilic-staining tegument, two suckers (oral and ventral), posteriorly located primordial genitalia and paired digestive caeca. These digeneans were identified as the metacercariae of Clinostomum attenuatum. This is the first record of Clinostomum attenuatum in these amphibian species.

Ambystoma↗

Eugenol stimulates lactate accumulation yet inhibits volatile fatty acid production and eliminates coliform bacteria in cattle and swine waste.

AIM: To determine how eugenol affects fermentation parameters and faecal coliforms in cattle and swine waste slurries stored anaerobically. METHODS AND RESULTS: Waste slurries (faeces:urine:water, 50:35:15) were blended with and without additives and aliquoted to triplicate 1-l flasks. Faecal coliforms were eliminated in cattle and swine waste slurries within 1 or 2 days with additions of eugenol at 10.05 mm (0.15%) and 16.75 mm (0.25%). At these concentrations volatile fatty acids (VFA) were reduced ca 70 and 50% in cattle and swine waste, respectively, over 6-8 weeks. Additionally, in cattle waste, eugenol stimulated the accumulation of lactate (>180 mm) when compared with thymol treatment (20 mm lactate). In swine waste, lactate accumulation did not occur without additives; eugenol and thymol stimulated lactate accumulation to concentrations of 22 and 32 mm, respectively. CONCLUSIONS: Eugenol added to cattle waste may be more beneficial than thymol because not only does it effectively control faecal coliforms and odour (VFA production), it also stimulates lactate accumulation. This in turn, causes the pH to drop more rapidly, further inhibiting microbial activity and nutrient emissions. SIGNIFICANCE AND IMPACT OF THE STUDY: Plant essential oils have the potential to solve some of the environmental problems associated with consolidated animal feeding operations. Thymol and eugenol reduce fermentative activity, thus, have the potential to reduce emissions of greenhouse gases and odour, and curtail transmission of pathogens in cattle and swine wastes.

Animals↗

Rete testis mucinous adenocarcinoma in a dog.

A bilateral testicular neoplasm from an 11-year-old mixed-breed male dog was removed surgically and examined histologically. The neoplasm was nonencapsulated and composed of acinar and tubular structures lined by one or more layers of neoplastic polyhedral epithelial cells with an abundant mucinous secretion. On histochemistry, all neoplastic cells and associated secretions were periodic acid-Schiff positive. Some neoplastic cells and all associated secretions were positive on mucicarmine stain, and some neoplastic cells, all the stroma, and associated secretions were positive on alcian blue stain. On immunohistochemistry, the neoplastic cells had strong diffuse cytoplasmic immunoreactivity for cytokeratin and vimentin, weak scattered cytoplasmic immunoreactivity for carcinoembryonic antigen and neuron-specific enolase, and no immunoreactivity for S-100. On the basis of histopathology, histochemistry, and immunohistochemical findings, a diagnosis of mucinous adenocarcinoma of rete testis was made. Rete testis adenocarcinoma is a well known but very rare neoplasm in humans. To our knowledge, this is the first report of the mucinous variant of adenocarcinoma of the rete testis in a dog.

Adenocarcinoma, Mucinous↗

Research methods for promotion of lung health.

The goal of health research is to develop new knowledge for action to improve health. Relevant health research includes study of diseases, their causes and their treatment/prevention as well as structure and utilisation of health services and policies to improve lung health. As resources are not infinite, priorities must be established. These are determined by the relative frequency of a condition, how much dysfunction or disability it produces and whether there are cost-effective means to deal with it. Epidemiology is the discipline used to address these issues. Using it, one can describe the distribution and relative importance of a condition (the descriptive study), identify determinants and define its natural history (the analytical study), assess methods of prevention, cure and amelioration (the experimental study) and evaluate the process and outcome of services (health services or operational research). Epidemiology addresses itself to determining causation among associated variables. Characteristics associated with causation include consistency, strength of association, specificity, dose response, temporal relationship, coherence, and experimental evidence. Epidemiology can truly be described as the 'basic science of public health.' When used strategically, it can create the new knowledge that is the cornerstone for improving the health of the whole population.

Biomedical Research↗

Getting started in research: the research protocol.

To be efficient and precise, research needs a 'road map', called the 'research protocol', which follows a standard format. It includes an abstract, study description, ethical considerations, significance of the study, the budget and a description of the investigators. Study description spells out the study question, the rationale for the study, including previous studies on the subject, the objectives, hypotheses and aims, design and methods, project management, strengths and limitations and a list of references. The objectives, hypotheses and aims are developed by outlining a general research topic (the objective), developing a hypothesis from the broad objective, translating it into the null hypothesis and then listing the steps by which the null hypothesis will be refuted or accepted (the aims). The design and methods describe the type of study to be undertaken, the population in which the study is carried out, including the sample size and statistical power, the selection of subjects, the methods of data collection, and outline of data management and statistical analysis. The detail of the protocol ensures that the study will be carried out successfully and is essential for all health research.

Data Collection↗

Choosing a research study design and selecting a population to study.

Epidemiological studies have been standardised into a group of 'designs'. The descriptive study describes disease by time, place and person and can develop hypotheses about associations between disease and possible determinants. The analytic study tests these hypotheses. The cross-sectional study measures the disease and determinants at a single point in time. The cohort study identifies those within a group with or without a determinant, and observes the occurrence of disease in the two groups. The case-control study identifies a group of patients with a disease and selects a group of persons from the same population who do not have the disease, comparing the presence of a determinant in the two groups. The experimental study, a type of cohort study, is one in which the investigator 'assigns' the determinant (a treatment) to one subgroup in a population and compares the occurrence of a disease between those with and those without the determinant. All such studies must ensure that the comparisons made have relevance to a defined population. This is done by selecting a 'representative' sample from that population. Carefully selecting a study design and population facilitates the creation of new knowledge while avoiding, as far as possible, important errors.

Biomedical Research↗

Measurement in epidemiology.

Data (information) are the building blocks of epidemiological research. Careful measurement, recording and handling of information are crucial to the research process. The nature of the data required must be precisely defined and its collection requires the use of reliable tools or instruments. Standardisation of definitions and procedures used in measurement helps to ensure comparability. Care in undertaking measurements and rigorous training of personnel carrying out the measurements help to ensure precision. Special care is necessary to ensure completeness and accuracy in recording the data. Information may be obtained from routine or especially designed forms and evaluated by counting deaths or cases of disease or measures of dysfunction. Questionnaires are a frequently used instrument for collecting information. They should include data identifying the individual being studied, followed by specific questions concerning diseases and determinants. To be useful, such questionnaires must be carefully structured. Diseases are usually compared by calculating 'rates' or 'risks', consisting of numerators (cases, events) and denominators (population). Prevalence and incidence are standard measures of 'risk'. The collection of high quality information (data) and its use to construct estimates of 'risk' or risk ratios form the basis of epidemiology.

Data Collection↗

Conducting research: practical steps.

Developing a research protocol and obtaining funding for carrying out the research are only the first steps in doing research. Understanding the means to conduct the research is equally important. As research is a joint effort of a team, a mechanism of collaboration must be developed to engage all those with an interest in the research. This includes the community in which the research is to be undertaken, representatives of those who will participate in the research, the academic community who will be involved in the research, and those who will sponsor the research. These individuals can be formed into a 'steering committee' to guide the development, conduct, analysis and communication of the research. Careful consideration must be given to the benefits and risks of the research. These must be precisely spelled out in the research protocol, and all aspects of the research must be independently evaluated for technical competence, accuracy, communication and liability for injury by an ethics review committee. The research must follow precisely the protocol developed. Administrative procedures, including recruitment and management of staff, outlining standard procedures and quality assurance procedures must be clearly outlined and followed. Carefully handling the information collected in a research project is vital to ensuring the quality and validity of the research.

Biomedical Research↗

Interpreting and reporting results.

Creating and disseminating knowledge is the goal of research. This is accomplished through critical analysis of systematically collected and clearly reported information. Critical analysis begins with the simple step of looking at the data collected prior to applying complex statistical analysis to make comparisons. Statistical analysis is approached in a standardised manner, depending on the type of data that has been collected. When a careful, stepwise standardised approach is applied to comparisons needed to address the research question, new knowledge is created and erroneous conclusions avoided. Following careful examination and analysis of the data, critical review is an important additional step to ensure that conclusions are correctly drawn. The process of peer review involved in publishing the research in the scientific literature is an important step to disseminating the new knowledge and ensuring its quality. Research is never complete without submitting it for publication in the peer-reviewed literature.

Data Interpretation, Statistical↗

Gastrointestinal cryptosporidiosis in a puppy.

An 8-week-old female Yorkshire terrier with a history of weakness, diarrhea and intestinal isosporiasis was euthanized and a post mortem examination performed. Histologically, there was severe gastrointestinal cryptosporidiosis, severe intestinal isosporiasis and thymic lymphoid depletion. PCR revealed visible bands for the actin and 18S rRNA genes but not for the acetyl CoA synthetase gene for Cryptosporidium spp. The PCR product for the actin gene was sequenced and found to have a 97.6-99.8% similarity to that of Cryptosporidium canis. To our knowledge, this is the first report of gastric cryptosporidiosis in a canine.

Acetyl Coenzyme A↗

Determinants of prognosis of COPD in the elderly: mucus hypersecretion, infections, cardiovascular comorbidity.

In this paper, the authors update the present knowledge about three risk factors for the prognosis of chronic obstructive pulmonary disease (COPD), which may be particularly relevant in elderly people: mucus hypersecretion, respiratory infections, and cardiovascular comorbidity. Chronic mucus hypersecretion (CMH) is a common respiratory symptom in old age, the relevance of which is analysed on the basis of data collected during the first three rounds of the Copenhagen City Heart Study. In subjects aged > or = 65 yrs, CMH was a strong predictor of the incidence of respiratory infections in a 10-yr follow-up period and it was also a strong predictor of death from COPD (relative risk=2.5). However, CMH was associated with consistently lower forced expiratory volume in one second (FEV1) values, but not with an accelerated decline of FEV1 in this sample of an elderly population. Acute respiratory infections (ARI) are extremely common at all ages, mostly mild self-limiting illnesses at a young age, but severe often fatal illnesses in elderly people already affected by a chronic disease such as COPD. This paper summarises the present knowledge about aetiology, pathology, prognostic relevance, and prevention of ARI. Furthermore, the areas in which further research is needed are listed. Clinical cohort studies clearly support the relevance of cardiovascular comorbidity for the short-and long-term prognosis of elderly subjects affected by severe COPD. In this paper, the recently demonstrated association between particulate air pollution and cardiovascular events is reported to suggest the presence of an extremely susceptible cluster of elderly subjects in the population identified by the copresence of chronic obstructive pulmonary disease and cardiovascular comorbidity.

Aged↗

Rats can discriminate illuminance, but not magnetic fields, as a stimulus for learning a two-choice discrimination.

In each of the two experiments, nine rats were trained for 64 trials (eight trials per day) to determine if they could acquire a two-choice discrimination based on a specified discriminative stimulus (S(D)). In one experiment, the S(D) was a change in ambient illumination, while in the second experiment the S(D) was a change in the combination of sinusoidal 60 Hz and static magnetic field (MF) and any cues attendant to energizing the coils that produced the MF exposure. The rats that had a change in illuminance as the S(D) learned the two-choice task easily, P <.001, whereas the rats having a change in MFs as the S(D) did not.

Animals↗