Biomedical subjects

C C Brown

Publications and source records attributed to C C Brown.

At least 19 recordsLinked to original sources

PubMed2006

Pathogenesis of Newcastle disease in commercial and specific pathogen-free turkeys experimentally infected with isolates of different virulence.

The pathogenesis of five different Newcastle disease virus (NDV) isolates representing all pathotypes was examined in commercial and specific pathogen-free (SPF) turkeys. Experimentally-infected birds were monitored clinically and euthanatized, with subsequent tissue collection, for examination by histopathology, by immunohistochemistry for the presence of NDV nucleoprotein, and by in situ hybridization for the presence of replicating virus. Clinically, the lentogenic pathotype did not cause overt clinical signs in either commercial or SPF turkeys. Mesogenic viruses caused depression in some birds. Turkeys infected with velogenic neurotropic and velogenic viscerotropic isolates showed severe depression, and neurologic signs. Histologic appearances for all strains had many similarities to lesions observed in chickens inoculated with the various isolates; that is, lesions were present predominantly in lymphoid, intestinal, and central nervous tissues. However, in general, disease among turkeys was less severe than in chickens, and turkeys could be considered a subclinical carrier for some of the isolates.

Animals↗

PubMed2006

Experimental pathogenesis for chickens, turkeys, and pigeons of exotic Newcastle disease virus from an outbreak in California during 2002-2003.

Exotic Newcastle disease virus (NDV) isolated from chickens during the 2002-2003 California outbreak (CA exotic Newcastle disease [END] virus) was inoculated into 4-week-old specific-pathogen-free (SPF) White Leghorn chickens, 3-week-old SPF Beltsville White turkeys, 6-week-old commercial Broad Breasted White turkeys, and 10- to 20-week-old racing pigeons, and the clinicopathologic features of disease were compared. Birds were monitored clinically and euthanized sequentially with collection of tissues. Tissues were examined by histopathology, by immunohistochemistry to detect viral nucleoprotein, and by in situ hybridization to detect viral mRNA. Clinically, infected chickens and SPF turkeys showed severe depression, and all died or were euthanized because of severe clinical signs by day 5 postinoculation. In these birds, histologic lesions were widespread and virus was detected in multiple organs. All infected commercial turkeys showed mild depression, and incoordination was observed in some birds. Histologic lesions were mild, and viral distribution was limited. In pigeons, only 1 bird showed overt clinical disease, and histologic lesions and viral distribution were present in limited organs. Consequently, susceptibility to highly virulent NDV was shown to vary among chickens, SPF turkeys, commercial turkeys, and pigeons. Additionally, we have evidence of CA END virus subclinical infections that suggest pigeons could be subclinical carriers of other virulent NDV.

Animals↗

PubMed2006

Accidental and intentional animal disease outbreaks: assessing the risk and preparing an effective response.

Intentional animal disease outbreaks are infrequent, if not rare, yet they carry the potential for disastrous consequences. Normal but accidental outbreaks are not uncommon and they must be handled efficiently, effectively and economically. And whatever its origin a disease will then follow its usual epidemiology. Therefore, the effectiveness in dealing with the normal, and the practice, experience and confidence gained, will significantly aid a country in how it minimises the cost of an intentional disease outbreak. The response is what determines the financial and economic costs of a disease outbreak. This paper provides an overview of the various threats, targets, and possible government responses, all of which is then expanded upon in detail in the other papers in this issue of the Review.

Animal Diseases↗

PubMed2003

Immunohistochemical analysis of two strains of lion (Panthera leo)-adapted canine distemper virus in ferrets (Mustela putorius furo).

Canine distemper virus (CDV) caused epizootics in lions (Panthera leo) in Tanzania's Serengeti National Park in 1994 and in captive lions and other Panthera spp. in the USA in 1991-1992. In this study, immunohistochemistry was used to compare viral distribution in tissues collected from ferrets (Mustela putorius furo) inoculated with one of the two lion-derived CDV isolates, either from Serengeti (A94-11/13) or from California (A92-27/20). The California isolate resulted in severe morbidity in all nine ferrets, whereas the Serengeti isolate resulted in severe morbidity in five of the nine ferrets. A slightly higher proportion of infected cells was found in many tissues in the Serengeti isolate-inoculated ferrets. These findings indicate that the pathogenicity of the California isolate is not directly related to the number of infected cells.

Animals↗

PubMed2002

The application of PCR-ELISA to the detection of Trypanosoma brucei and T. vivax infections in livestock.

Teneral tsetse flies infected with either Trypanosoma brucei or T. vivax were fed on healthy cattle. Blood samples collected daily from the cattle were examined by microscopy for the presence of trypanosomes, in thick smear, thin smear and in the buffy coat (BC). All the cattle fed upon by infected tsetse developed a fluctuating parasitaemia. DNA was extracted from the blood of these cattle and subjected to polymerase chain reaction (PCR) using oligonucleotide primers specific for T. brucei or T. vivax. The PCR products unique to either T. brucei or T. vivax were identified following amplification of DNA from the blood samples of infected cattle, whereas none was detectable in the DNA from the blood of the cattle exposed to non-infected teneral tsetse. In a concurrent set of experiments, one of the oligonucleotide primers in each pair was biotinylated for use in PCR-ELISA to examine all the blood samples with this assay. Both the PCR and the PCR-ELISA revealed trypanosome DNA in 85% of blood samples serially collected from the cattle experimentally infected with T. brucei. In contrast, the parasitological assays showed trypanosomes in only 21% of the samples. In the blood samples from cattle experimentally infected with T. vivax, PCR and PCR-ELISA revealed trypanosome DNA in 93 and 94%, respectively. Microscopy revealed parasites in only 63% of the BCs prepared from these cattle. Neither PCR nor PCR-ELISA detected any trypanosome DNA in blood samples collected from the animals in the trypanosome-free areas. However, both assays revealed the presence of trypanosome DNA in a number of blood samples from cattle in trypanosomosis-endemic areas.

Animals↗

PubMed2002

Fumonisin B1-induced localized activation of cytokine network in mouse liver.

Fumonisin B1 (FB1), a mycotoxin produced primarily by Fusarium veticillioides and related fungi, is a carcinogen and causative agent of various animal diseases. Our previous studies indicated the involvement of tumor necrosis factor-alpha (TNFalpha) in FB1-induced hepatotoxicity. Male B6,129 mice (five/group) were injected subcutaneously with vehicle or 2.25 mg/kg/day of FB1 for 5 days and sampled 1 day after the last treatment. FB1 treatment caused an increased expression of TNFalpha, interferon gamma (IFNgamma) and interleukin (IL)-12 p40 in liver without any changes in kidney or spleen, suggesting the localized site of their production. IL-1beta cytokine expression was increased in liver and kidney after FB1 exposure. Cells involved in TNFalpha production after FB1 treatment in liver were identified as Kupffer cells. FB1 increased alanine aminotransferase in plasma and increased apoptotic cells in liver. Selective increase in proinflammatory T helper (Th)1-cytokines (IL-12 and IFNgamma) and TNFalpha with no alteration in Th2-cytokines (IL-4, IL-6 and IL-10) suggest the involvement of IL-12, produced by Kupffer cells, in induction of IFNgamma production by natural killer (NK) cells and/or NK1+ T cells, which can undergo a positive amplification loop with TNFalpha produced by macrophages or other hepatic cells to elicit the toxic reaction.

Alanine Transaminase↗

PubMed2002

Pathogenesis of six pigeon-origin isolates of Newcastle disease virus for domestic chickens.

The pathogenesis of six pigeon-origin isolates of Newcastle disease virus (NDV) was investigated in chickens. Four isolates were previously defined as the variant pigeon paramyxovirus 1 (PPMV-1), and two isolates were classified as avian paramyxovirus 1 (APMV-1). Birds inoculated with PPMV-1 isolates were euthanatized, and tissue samples were collected at 2, 5, and 10 days postinoculation (DPI). Birds inoculated with APMV-1 isolates died or were euthanatized, and tissue samples were collected at 2, 4, and 5 DPI. Tissues were examined by histopathology, immunohistochemistry (IHC) for the presence of NDV nucleoprotein, and in situ hybridization (ISH) for the presence of viral mRNA for the matrix gene. Spleen sections were stained by the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay and by IHC using an anti-active caspase-3 antibody (IHC-Casp) to detect apoptotic cells. Brain sections of PPMV-1-infected birds were examined by IHC to detect T and B lymphocytes and glial fibrillary acidic protein (GFAP). Histologically, birds inoculated with PPMV-1 isolates had marked lesions in the heart and brain. Presence of viral nucleoprotein and viral mRNA in the affected tissues was confirmed by IHC and ISH, respectively. Numerous reactive astrocytes were observed in brain sections stained for GFAP Among all the isolates, the IHC-Casp demonstrated that apoptosis was very prominent in the ellipsoid-associated cells of the spleen at 2 DPI. Results of the TUNEL assay indicated that apoptotic cells were prominent at 5 DPI and were more randomly distributed. The clinical signs and gross and histopathologic changes observed in the APMV-1-infected birds were characteristic of an extensive infection with highly virulent NDV evident by IHC.

Animals↗

PubMed2001

Design and serendipity in establishing a large cohort with wide dietary intake distributions : the National Institutes of Health-American Association of Retired Persons Diet and Health Study.

In 1995-1996, the authors mailed a food frequency questionnaire to 3.5 million American Association of Retired Persons members who were aged 50-69 years and who resided in one of six states or two metropolitan areas with high-quality cancer registries. In establishing a cohort of 567,169 persons (340,148 men and 227,021 women), the authors were fortunate in that a less-than-anticipated baseline response rate (threatening inadequate numbers of respondents in the intake extremes) was offset by both a shifting and a widening of the intake distributions among those who provided satisfactory data. Reported median intakes for the first and fifth intake quintiles, respectively, were 20.4 and 40.1 (men) and 20.1 and 40.0 (women) percent calories from fat, 10.3 and 32.0 (men) and 8.7 and 28.7 (women) g per day of dietary fiber, 3.1 and 11.6 (men) and 2.8 and 11.3 (women) servings per day of fruits and vegetables, and 20.7 and 156.8 (men) and 10.5 and 97.0 (women) g per day of red meat. After 5 years of follow-up, the cohort is expected to yield nearly 4,000 breast cancers, more than 10,000 prostate cancers, more than 4,000 colorectal cancers, and more than 900 pancreatic cancers. The large size and wide intake range of the cohort will provide ample power for examining a number of important diet and cancer hypotheses.

Aged↗

PubMed2001

Occurrence of Ichthyophthirius multifiliis within the peritoneal cavities of infected channel catfish Ictalurus punctatus.

Ichthyophthirius multifiliis is a ciliated protozoan parasite that infects the skin and gills of freshwater fish. This report describes the unusual finding of I. multifiliis within the peritoneal cavities of experimentally infected channel catfish Ictalurus punctatus. Twenty catfish fingerlings were exposed to I. multifiliis theronts using a standardized protocol. Five infected fish and 2 control fish were killed at various time points after infection and their tissues examined. Formalin-fixed, paraffin embedded sections were processed for light microscopy and immunohistochemical detection of I. multifiliis immobilization antigen. Trophonts were observed in skin and gill sections of all exposed fish. Parasites were associated with epithelial hyperplasia, focal areas of cellular disruption and necrosis. In addition to these usual sites of infection, individual trophonts were unexpectedly found within the peritoneal cavities of 4 fish. Staining for parasite antigen facilitated their detection within abdominal adipose tissue or adjacent to intestines. This discovery is interesting as it suggests I. multifiliis may be found in tissues other than the skin and gills during the course of a normal infection.

Animals↗

PubMed2001

SJL/J mice are highly susceptible to infection by mouse adenovirus type 1.

Mouse adenovirus type 1 (MAV-1) targets endothelial and monocyte/macrophage cells throughout the mouse. Depending on the strain of mouse and dose or strain of virus, infected mice may survive, become persistently infected, or die. We surveyed inbred mouse strains and found that for the majority tested the 50% lethal doses (LD(50)s) were >10(4.4) PFU. However, SJL/J mice were highly susceptible to MAV-1, with a mean LD(50) of 10(-0.32) PFU. Infected C3H/HeJ (resistant) and SJL/J (susceptible) mice showed only modest differences in histopathology. Susceptible mice had significantly higher viral loads in the brain and spleen at 8 days postinfection than resistant mice. Infection of primary macrophages or mouse embryo fibroblasts from SJL/J and C3H/HeJ mice gave equivalent yields of virus, suggesting that a receptor difference between strains is not responsible for the susceptibility difference. When C3H/HeJ mice were subjected to sublethal doses of gamma irradiation, they became susceptible to MAV-1, with an LD(50) like that of SJL/J mice. Antiviral immunoglobulin G (IgG) levels were measured in susceptible and resistant mice infected by an early region 1A null mutant virus that is less virulent that wild-type virus. The antiviral IgG levels were high and similar in the two strains of mice. Taken together, these results suggest that immune response differences may in part account for differences in susceptibility to MAV-1 infection.

Adenoviridae Infections↗

PubMed2001

Pathogenesis of experimental vesicular stomatitis virus (New Jersey serotype) infection in the deer mouse (Peromyscus maniculatus).

The pathogenesis of vesicular stomatitis virus (VSV) infection has not been investigated previously in native New World rodents that may have a role in the epidemiology of the disease. In the present study, 45 juvenile and 80 adult deer mice (Peromyscus maniculatus) were inoculated intranasally with VSV New Jersey serotype (VSV-NJ) and examined sequentially over a 7-day period. Virus was detected by means of immunohistochemistry and in situ hybridization in all tissues containing histologic lesions. Viral antigen and mRNA were observed initially in olfactory epithelium neurons, followed by olfactory bulbs and more caudal olfactory pathways in the brain. Virus also was detected throughout the ventricular system in the brain and central canal of the spinal cord. These results support both viral retrograde transneuronal transport and viral spread within the ventricular system. Other tissues containing viral antigen included airway epithelium and macrophages in the lungs, cardiac myocytes, and macrophages in cervical lymph nodes. In a second experiment, 15 adult, 20 juvenile, and 16 nestling deer mice were inoculated intradermally with VSV-NJ. Adults were refractory to infection by this route; however, nestlings and juveniles developed disseminated central nervous system infections. Viral antigen also was detected in cardiac myocytes and lymph node macrophages in these animals. Viremia was detected by virus isolation in 35/72 (49%) intranasally inoculated juvenile and adult mice and in 17/36 (47%) intradermally inoculated nestlings and juveniles from day 1 to day 3 postinoculation. The documentation of viremia in these animals suggests that they may have a role in the epidemiology of vector-borne vesicular stomatitis.

Animals↗

PubMed2001

Localization of avian leukosis virus subgroup J in naturally infected chickens by RNA in situ hybridization.

The novel subgroup J of avian leukosis virus (ALV-J) has emerged as a significant cause of myeloid neoplasia and weight suppression in broiler chickens. We investigated viral tropism using RNA in situ hybridization (ISH) in naturally infected chickens. Formalin-fixed tissues were collected from 12-day-old embryos (seven infected, two control) and from 0-week-old (four infected, one control), 3-week-old (five infected, one control), 6-week-old (five infected, one control), and 9-week-old (10 infected, two control) chickens naturally infected with ALV-J in ovo. A 636-base antisense riboprobe complementary to the 3' and 5' ends of the pol and env viral genes, respectively, was constructed. Strong positive staining was present in cardiac myocytes, Purkinje fibers, vascular and pulmonary smooth muscle, renal glomeruli, distal tubules, and pituitary glands. Light staining was present in gastrointestinal smooth muscle, thyroid and adrenal glands, and follicular medullae in the cloacal bursa. Staining was not present in any hematopoietic precursors. Tissues from newly hatched chicks exhibited the strongest and most consistent staining, whereas staining in embryos was minimal. RNA ISH confirmed the presence of ALV-J-specific nucleic acid within cytoplasmic inclusions in cardiac myocytes, Purkinje fibers, pituitary glands, and renal glomeruli. Viral tropism for cardiac myocytes and Purkinje fibers may relate pathogenetically to the cardiomyopathy and congestive heart failure described in index chicken flocks infected with ALV-J. Viral tropism for endocrine organs may relate pathogenetically to the weight suppression associated with infection.

Animals↗

PubMed2000

Bladder cancer: race differences in extent of disease at diagnosis.

BACKGROUND: Blacks are less likely than whites to develop bladder cancer; although once diagnosed, blacks experience poorer survival. This study sought to examine multiple biological and behavioral factors and their influence on extent of disease. METHODS: A population-based cohort of black bladder cancer patients and a random sample of frequency-matched white bladder cancer patients, stratified by age, gender, and race were identified through cancer registry systems in metropolitan Atlanta, New Orleans, and the San Francisco/Oakland area. Patients were ages 20-79 years at bladder cancer diagnosis from 1985-1987, and had no previous cancer history. Medical records were reviewed at initial diagnosis. Of the patients selected for study, a total of 77% of patients was interviewed. Grade, stage, and other variables (including age, socioeconomic status, symptom duration, and smoking history) were recorded. Extent of disease was modeled in 497 patients with urothelial carcinoma using logistic regression. RESULTS: Extent of disease at diagnosis was significantly greater in Blacks than in Whites. Older age group, higher tumor grade, larger tumors, and presence of carcinoma in situ were related to greater extent of disease in blacks and in whites. Large disparities between blacks and whites were found for socioeconomic status and source of care. Blacks had greater symptom duration and higher grade. Black women were more likely to have invasive disease than white women; this difference was not seen among men. Blacks in unskilled occupational categories, perhaps reflecting socioeconomic factors, were at much higher risk for muscle invasion than whites. CONCLUSIONS: While specific relationships between variables were noted, an overall pattern defining black and white differences in stage did not emerge. Future studies should examine the basis upon which occupation and life style factors operate by using biochemical and molecular methods to study the genetic factors involved.

Adult↗

PubMed2000

Evaluation of alternative approaches to assign nutrient values to food groups in food frequency questionnaires.

Although every food frequency questionnaire (FFQ) requires a nutrient database to produce nutrient intake estimates, it is often unclear how a particular database has been generated. Moreover, alternative methods for constructing a database have not been rigorously evaluated. Using 24-hour recalls from the 1994-1996 Continuing Survey of Food Intake by Individuals, the authors categorized 5,261 individual foods reported by 10,019 adults into 170 food groups consistent with line items on an FFQ. These food groups were used to generate 10 potential nutrient databases for a FFQ that varied by whether the authors 1) used means or medians, 2) did or did not consider age, 3) incorporated collapsing strategies for small age-gender-portion size cells, 4) excluded outliers in a regression, and 5) used weighted median nutrient density x age-gender-portion size-specific median gram weights (Block method). Mean error, mean squared error, and mean absolute error were calculated and compared across methods, with error being the difference in total observed (from recalls for each individual) and total estimated intake (from each of the 10 methods) for seven nutrients. Mean methods for assigning nutrients to food groups were superior to median approaches for all measurements. Among the mean methods, no single variation was consistently better.

Adult↗

PubMed2000

The iliolumbar ligament: three-dimensional volume imaging and computer reformatting by magnetic resonance: a technical note.

STUDY DESIGN: An assessment of magnetic resonance imaging techniques of the iliolumbar ligament. OBJECTIVES: To identify a technique to better image the iliolumbar ligament. SUMMARY OF BACKGROUND DATA: The iliolumbar ligament plays an important role in providing lumbosacral stability. Two-dimensional magnetic resonance imaging of the lumbar spine only provides a fragmented representation of the ligament. METHODS: A two-part study was performed. In the first part, three cadaver pelvi were dissected, and the individual bands of the iliolumbar ligament were identified. Computer reformatting of magnetic resonance three-dimensional volume images then were performed, correlating the structural characteristics of the iliolumbar ligament to its magnetic resonance image. In the second part of the study, the lumbosacral region of three groups of patients were evaluated. Group I was studied with routine magnetic resonance imaging techniques of the intervertebral disc regions. Group II was studied with routine contiguous axial magnetic resonance imaging of the lumbosacral spine. Group III was studied with computer reformatting of three-dimensional volume images of the lumbosacral spine. RESULTS: Accurate imaging of the iliolumbar ligament of cadaver specimens was achieved with three-dimensional volume imaging and computer reformatting. Routine imaging of the intervertebral disc region as well as contiguous axial imaging of the spine depicted only limited segments of the iliolumbar ligament. Three-dimensional volume imaging and computer reformatting allowed precise imaging of the iliolumbar ligament in all patients, demonstrating the ligament orientation as well as length, width, and depth. CONCLUSION: Only images of the iliolumbar ligament obtained through computer reformatting of three-dimensional volume averaging from L3 to the sacral ala correlated with the ligament's structural characteristics.

Adult↗

PubMed2000

Development of a molecular probe to baboon interleukin-10 mRNA for in situ hybridization during experimental schistosomiasis.

A nucleic acid probe complementary to baboon interleukin 10 (IL-10) mRNA was developed for in situ hybridization. Highly conserved IL-10 protein sequences from several mammals were aligned to design oligonucleotide primers flanking a 270-bp sequence of the target cDNA. RNA was isolated from stimulated peripheral blood mononuclear cells (PBMC). IL-10 cDNA was reverse-transcribed from the total PBMC RNA and amplified with the polymerase chain reaction (PCR). Cloning and sequencing of the PCR product confirmed it to be of baboon IL-10 origin, with 97.8% identity to human and 100% identity to macaque mRNA sequences. The baboon IL-10 DNA probe hybridized in Southern blots to a 7.9-Kbp or 8.6-Kbp band after digestion of genomic baboon DNA with Bam H1 or Eco R1, respectively. Preliminary results with an antisense riboprobe derived from this sequence showed the presence of IL-10 mRNA in sections of granulomatous tissues.

Animals↗

PubMed2000

Emerging zoonoses: crossing the species barrier.

The ability of infectious disease agents to cross the species barrier has long been recognised for many zoonotic diseases. New viral zoonotic diseases, such as acquired immune deficiency syndrome (AIDS), caused by human immunodeficiency viruses 1 or 2, emerged in the 1980s and 1990s, and have become established in the human population. Influenza virus continues to find new ways to move from avian species into humans. The filoviruses and the newer paramyxoviruses, Hendra and Nipah, highlight the increasing proclivity of some animal viral agents to infect human populations with devastating results. A previously unknown transmissible spongiform encephalopathy, bovine spongiform encephalopathy, has emerged in cattle in Europe and spread to humans as well as other animal species. A novel toxicosis, caused by Pfiesteria spp. dinoflagellates, has become a secondary problem in some areas where large fish kills have occurred. The increasing proximity of human and animal populations has led to the emergence of, or increase in, bacterial zoonoses such as plague, leptospirosis and ehrlichiosis. The factors which influence the ability of each infectious agent to effectively across the species barrier and infect new cells and populations are poorly understood. However, for all of these diseases, the underlying theme is the growth of the human population, the mobility of that population, and the efforts expended to keep that population nourished.

Animals↗

PubMed2000

Prevalence of papillomatous digital dermatitis among culled adult cattle in the southeastern United States.

OBJECTIVE: To determine prevalence of papillomatous digital dermatitis (PDD) among culled adult dairy and beef cattle in the southeastern United States. ANIMALS: 815 cattle examined during 4 visits to a slaughterhouse. PROCEDURE: The left hind foot of each animal was examined for gross lesions of PDD. Breed and sex of the animals were recorded. Lesions were examined histologically for pathologic changes and bacteria, especially spirochetes. RESULTS: 22 of 76 (29%) dairy cattle and 29 of 739 (4%) beef cattle had gross lesions of PDD. Detection of lesions was not associated with sex of dairy cattle, but male beef cattle were more likely to have lesions of PDD than were female beef cattle. Histologically, acute and chronic lesions were seen; the most severe changes were localized to the stratum corneum. Spirochetes were seen in lesions from 31 of 51 (61%) cattle. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that PDD is common among culled adult cattle. Prevalence was higher in culled adult dairy cattle than in culled adult beef cattle.

Abattoirs↗