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Biomedical subjects

R D Hunt

Publications and source records attributed to R D Hunt.

At least 55 records · Page 3Linked to original sources
PubMed1983

Failure of Herpesvirus saimiri to enhance atherogenesis in owl monkeys (Aotus trivirgatus).

A retrospective study was performed to evaluate the potential of a mammalian oncogenic virus, Herpesvirus saimiri, to cause atherosclerosis in owl monkeys (Aotus trivirgatus). This was undertaken since an avian oncogenic herpesvirus, Marek's disease virus, does so in chickens. Data from earlier studies were reviewed and 3 groups of animals were selected. These included 23 animals infected with herpesvirus that died an average of 156 days later with malignant lymphoma; 11 infected an average of 207 days before being killed without lymphoma; and 21 uninfected control animals that died from a variety of diseases. Aortas and hearts from all animals were recovered from storage in formalin and examined for histopathological evidence of atherosclerosis in aortas and coronary arteries. Mild to moderate atherosclerosis characterized by intimal proliferation and the presence of fat droplets was present in 60% of the monkeys and did not differ in occurrence between the groups. Mean intimal thickness did not vary significantly between groups either. A case of naturally-occurring severe atherosclerosis is also reported here. Thus, although this species is susceptible to atherosclerosis, neither the occurrence nor severity of that disease is affected by infection with an oncogenic virus within the time periods studied here.

Animals↗
PubMed1983

Transmission of naturally occurring lymphoma in macaque monkeys.

Spontaneously occurring rhesus monkey lymphomas were transmitted into healthy rhesus monkeys by using tumor cell suspensions. The naturally arising tumors included an immunoblastic sarcoma and an undifferentiated lymphoma. Recipient animals developed undifferentiated lymphomas, poorly differentiated lymphomas, or parenchymal lymphoproliferative abnormalities suggestive of early lesions of lymphoma. Some of these animals developed such opportunistic infections as cytomegalovirus hepatitis and cryptosporidiosis. They also showed evidence of an abnormal circulating peripheral blood mononuclear cell. These findings, all characteristic of the acquired immune deficiency syndrome (AIDS) of macaques, suggest a link between these transmissible lymphomas and AIDS in macaque monkeys.

Animals↗
PubMed1983

Acquired immunodeficiency syndrome in a colony of macaque monkeys.

A naturally occurring immunodeficiency syndrome has been seen in a captive colony of macaque monkeys. This syndrome is seen primarily in the species Macaca cyclopis. Affected animals died with lymphomas (a rare disease in macaques) or such opportunistic infections as Pneumocystis carinii and noma (necrotizing gingivitis). These M. cyclopis exhibited anemia, neutropenia, and a circulating bizarre immature monocyte. In addition, liver function tests suggested hepatitis. Pokeweed mitogen-, concanavalin A-, and xenogeneic cell-stimulated proliferative responses by lymphocytes of animals with the syndrome were dramatically diminished. The T4 (helper, inducer)/T8 (suppressor, cytotoxic) ratio in the peripheral blood mononuclear T-cell populations of M. cyclopis in this colony are decreased when compared with those from either Macaca mulatta in the same colony or normal humans. Epidemiologic evidence implicates a common source agent in this syndrome. The similarity of this syndrome in macaques to human acquired immunodeficiency syndrome suggests that it may provide an important model for studying the human syndrome.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Histopathologic changes in macaques with an acquired immunodeficiency syndrome (AIDS).

The authors recently described the clinical course of an Acquired Immunodeficiency Syndrome (AIDS) in a colony of macaque monkeys. In the present study, they have reviewed the histopathology of tissues obtained from a cohort of 16 animals with this clinical syndrome at necropsy. They found evidence in these animals of several opportunistic infections, including cytomegalovirus (CMV), simian virus 40 (SV-40), and noma. Furthermore, a number of other unusual pathologic processes were noted. In 4 animals an array of lymphoproliferative disorders was observed, ranging from multiple nodules of lymphocytes in the kidney, liver, and bone marrow, to frank lymphoma. Evidence of retroperitoneal fibrosis was found in 3 of the animals. Finally, amyloidosis was observed in several animals; in two instances it was present only in the mucosa of the small intestine.

Acquired Immunodeficiency Syndrome↗
PubMed1982

Assessment of brain function in clinical pediatric research: behavioral and biological strategies.

Psychobiological research in child psychiatry requires rigorous assessment of behavior and multiple perspectives on brain function through neurochemical, neuroendocrine, psychophysiological, and other advanced methods. The serious neuropsychiatric disorders of childhood, such as autism, attention deficit disorder, and language disorders, can be studied in complementary clinical protocols aimed at explicating patterns of behavioral and metabolic dysfunction which characterize various clinical syndromes. Clinical research with children raises sensitive ethical issues; the ethical problems can be addressed when children and families are active collaborators with the investigators and a long-term relationship is established. In this setting, participation in research can facilitate better treatment for a child. The use of novel biological strategies, such as pharmacological challenge tests, permits evaluation of the relation of specific neuronal systems to behavioral dimensions in clinical disorders. The development of a new treatment for Tourette's syndrome illustrates the integration of basic and clinical research methods.

Catecholamines↗
PubMed1982

Strategies for study of the neurochemistry of attention deficit disorder in children.

The interpretation of neurochemical studies of attention deficit disorder (ADD) with hyperactivity is complicated by the variability in diagnosis and by the limitations of single neurochemical measures--whose levels may be compensated by chronic feedback mechanisms. This article reviews previous neurochemical studies of ADD and proposes the use of single-dose neurochemical probes. Administration of a provocative agent with subsequent sequential measures of plasma levels of neurotransmitters, their metabolites, and hormones may help define the responsivity of neurochemical systems. Blood levels of drugs and neurotransmitters following single doses of methylphenidate and clonidine are studied as a strategy to explore the responsivity of dopaminergic and noradrenergic mechanisms in ADD.

Attention Deficit Disorder with Hyperactivity↗
PubMed1979

Plasma levels of d-amphetamine in hyperactive children. Serial behavior and motor responses.

Amphetamine has been clearly documented to be an efficacious treatment for hyperactive children. The pharmacokinetics of amphetamine have been studied in adults, but not in children. Sixteen male children who scored greater than 2SD from norms on Factors I and IV of Conner's Teacher Rating Scale and who were not excluded for reasons to do with medical or psychiatric conditions, intelligence, or age, had a plasma d-amphetamine apparent elimination half-life of 6.8 +/- 0.5h. Peak plasma level occurred between 3 and 4h (62.7 +/- 3.8 and 65.9 +/- 3.6 ng/ml, respectively). Six of these children had a repeat study and there were no significant differences within subject in apparent elimination half-lives and attained peak blood levels. The variation in plasma levels was greater during absorption than during elimination. Both behavioral and motor activity responses as analyzed by differences between amphetamine and placebo days (by paired t-tests) indicate significant responses between hours 1--4; however, these responses do not correlate with plasma amphetamine levels; they occur during the absorption phase. The decreased response to later similar plasma levels of d-amphetamine may be related to depletion of catecholamine stores, to replacement by a 'false neurotransmitter' metabolite of amphetamine, or to alteration in receptor sensitivity.

Child↗
PubMed1978

Huntington's dementia. Clinical and neuropsychological features.

The neuropsychiatric syndrome of Huntington's disease is outlined in this report with an emphasis on the cognitive deficits that lend themselves to future neurobehavioral research. Eighteen patients without disabling cognitive or psychiatric symptoms were evaluated for a period of 3 to 15 weeks, with assessment of their cognitive disorder, psychiatric, and neurological symptoms. Neuropsychological examination included repeated mental status examination, the Wechsler Adult Intelligence Scale (WAIS), and, for some, parietal lobe testing. In addition to suffering from a loss of finely detailed memories, patients demonstrated impaired organizing, sequencing, planning, and recalling of information on request. On the WAIS, mean verbal and performance scores were not significantly different. Neuropsychological findings suggested that the Huntington's disease pattern of cognitive impairment is not initially diffuse and homogeneous, but characterized by a relative sparing of several higher cortical functions. Many patients had increased irritability and labile affect. The similarity of Huntington's disease to frontal lobe syndromes is also discussed.

Adult↗
PubMed1978

Spontaneous infectious diseases of marmosets.

The various species of marmosets are susceptible to a wide variety of infectious agents of which only a few have been fully characterized. Little is known concerning spontaneous disease in their natural habitat, and often deaths in the laboratory go unexplained. In captivity, Herpesvirus-T infection appears to be the most important viral infection, but serious disease may also follow infection with measles virus (rubeola) and an unidentified paramyxovirus. Bacterial diseases are multiple, but rarely occur as epizootics. Various species of Salmonella, Yersinia, Klebsiella, and Diplococcus are among the more frequent pathogens. Mycoses and parasitic infections are also numerous, but most do not result in major losses.

Animals↗
PubMed1978

A paramyxovirus causing fatal gastroenterocolitis in marmoset monkeys.

A paramyxovirus has been isolated, identified and characterized. The virus causes a disease characterized clinically by severe diarrhea, dehydration and death. Microscopically the disease is characterized as a proliferative gastroenterocolitis with focal necrosis of the mucosa, by giant syncytial cells and eosinophilic intranuclear and intracytoplasmic inclusions. The virus is closely related to measles virus antigenically.

Animals↗