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D J Cameron

Publications and source records attributed to D J Cameron.

At least 19 recordsLinked to original sources
PubMed1992

False positive.

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False Positive Reactions↗
PubMed1991

Lyme test problems.

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Antibodies, Bacterial↗
PubMed1987

Effect of neuropeptides on macrophage mediated cytotoxicity in normal donors and cancer patients.

The role of enkephalins, endorphins and other neuropeptides produced by the nervous system in the alteration of immune responsiveness is generally unknown. The present studies were undertaken to investigate the role of these neuropeptides in the modulation of cytotoxicity induced by LPS activated macrophages obtained from normal donors as well as breast cancer and Hodgkins disease patients. When the macrophages from normal donors were pretreated with these neuropeptides for 1 hr prior to co-culturing with target cells, macrophage mediated cytotoxicity was enhanced with 10(-6) M and 10(-8) M of [met]-enkephalin, 10(-6) M of [leu]-enkephalin and 10(-6) M and 10(-12) M of alpha-endorphin. However, when the macrophages were co-cultured with target cells in the presence of the neuropeptides, it was observed that 10(-6) M and 10(-12) M of alpha-endorphin enhanced cytotoxicity whereas no enhancement in cytotoxicity was observed when [met]-enkephalin or [leu]-enkephalin were added to the cultures. In fact, it appears that 10(-10) M of [met]-enkephalin and 10(-12) M of [leu]-enkephalin actually suppressed macrophage mediated cytotoxicity. When the opioid antagonist Naloxone was incubated with the neuropeptides in the presence of the macrophages the enhancement of macrophage killing produced by [met]-enkephalin, [leu]-enkephalin or alpha-endorphin was suppressed. When the breast cancer patients' macrophages were pretreated with these neuropeptides, enhancement in cytotoxicity was observed at 10(-10) M of [met]-enkephalin, and [leu]-enkephalin and at 10(-8) M and 10(-12) M of alpha-endorphin.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗
PubMed1979

The spectrum of cow's milk allergy in childhood. Clinical, gastroenterological and immunological studies.

Seventeen of 52 children suspected of having cow's milk allergy had this diagnosis confirmed after milk challenge in hospital. A broad spectrum of reactions was obsserved including skin eruptions, respiratory symptoms and gastrointestinal disturbance. Not all patients with gastrointestinal symptoms showed small bowel mucosal damage. Only patients with skin reactions had positive skin tests. IgA deficiency and IgE elevation were common. Four patients had symptoms within 3 days of birth. Twelve children tolerated cow's milk by three years of age. Cow's milk allergy can cause a variety of symptoms. Challenge with milk for several days may be required before allergic manifestations can be demonstrated.

Animals↗
PubMed1979

Diarrhea and rotavirus infection associated with differing regimens for postnatal care of newborn babies.

Surveillance of 2,041 babies born during 4 winter months in one obstetric hospital in Melbourne, Australia, showed that 215 developed acute diarrhea during the first 2 weeks of life. Babies requiring special care from birth had a high incidence of sporadic diarrhea (36%). The incidence of diarrhea among healthy full-term babies was low if they were "rooming-in" with their mothers (2 to 3%) but high if they were housed in communal nurseries (29%). The most important factor influencing incidence of diarrhea was proximity to other newborn babies and frequency of handling by related adults. Breast feeding did not always protect babies from diarrhea. Excretion of rotaviruses was temporally retlated to diarrhea in 61 to 76% of healthy full-term babies and in 44% of babies requiring special care. Other eneteric pathogens, including enerotoxigenic Escherichia coli, were occasionally isolated. Calculation of the ratios of symptomatic to asymptomatic infection suggests that babies requiring special care are much more likely to develop symptomatic illness after rotavious infection than are full-term babies.

Australia↗
PubMed1979

Cytotoxicity of human macrophages for tumor cells. Enhancement by human lymphocyte mediators.

Human macrophages, derived from peripheral blood monocytes, acquire enhanced cytotoxicity for human target cells after incubation in mediator-rich supernates from antigen-stimulated lymphocytes. Maximum cytotoxicity was observed after 24-h incubation in mediators. In comparison to normal macrophages, mediator-activated macrophages were cytotoxic to five of the six malignant cell lines tested but had no effect on five nonmalignant cell lines. In 20 experiments with one target (SK-BR-3), mean cytotoxicity was 23 +/- 2.7% and with another target (MA-160), was 29 +/- 3.4%. Macrophages became cytotoxic after 8-h incubation with mediators and the enhanced cytotoxicity persisted for at least 40 h after the lymphocyte mediators were removed. These findings are consistent with the hypothesis that macrophages, activated by antigen-induced lymphocyte mediators, can contribute to the host resistance to tumor growth in man.

Cell Division↗
PubMed1978

Pattern of shedding of two noncultivable viruses in stools of newborn babies.

Noncultivable viruses have been associated with diarrhea affecting newborn babies in obstetric hospital nurseries. Persisting infection in a special care nursery in Melbourne, Australia, permitted a study of the pattern of excretion of these viruses. Ten babies admitted to the nursery within 2 hr of birth were randomly selected for prospective study. Feces were collected daily for 14 days and were examined by electron microscopy. All ten babies excreted detectable amounts of duovirus (rotavirus, HRVL agent, IGV) for at least 1 day. Age at onset of excretion varied from 2 to 13 days. Eight of the ten babies developed diarrhea. Excretion of duovirus preceded the onset of diarrhea by 12--72 hr and persisted for at least 3 days. Seven of the ten babies also excreted detectable amounts of 28-nm virus-like particle for 3--8 days. The identity of this particle is unknown. Morphologically it resembles Norwalk agent and "astrovirus." Excretion of this 28-nm particle coincided with symptoms of diarrhea in four babies, all of whom were also excreting duovirus. It is concluded that most newborn babies admitted to a nursery where duovirus infection is endemic will excrete this virus at least once during the first 2 weeks of life. Excretion of virus particles will either precede development of diarrhea or be asymptomatic. Selective isolation of babies with diarrhea is thus unlikely to control spread of duovirus infection within a hospital nursery.

Australia↗
PubMed1978

Noncultivable viruses and neonatal diarrhea: fifteen-month survey in a newborn special care nursery.

During a 15-month period of surveillance, diarrhea developed in 257 of 913 babies (28%) admitted within 2 hours of birth to a special care nursery in Melbourne, Australia. Diarrhea was seasonal, affecting a maximum of 43% of babies admitted during one winter month (July) and a minimum of 13% of babies admitted during one summer month (December). Diarrhea was no more frequent nor more severe in babies of very low birth weight or of very early gestational age. Two noncultivable viruses were located by electron microscopy in feces from babies with or without diarrhea. Excretion of a reovirus-like particle (rotavirus, duovirus, human reovirus-like agent, infantile gastroenteritis virus) was temporally related to diarrheal symptoms. Asymptomatic infection with this virus also occurred. A 28-nm virus-like particle was excreted by some babies, but it could not be implicated on epidemiological grounds in the etiology of the diarrhea. Rotavirus infection may be an important cause of endemic diarrhea in nurseries for the newborn. Infection may be difficult to control or eradicate, since it is often asymptomatic and may be influenced by infection in the community at large.

Australia↗
PubMed1976

New virus associated with diarrhoea in neonates.

Since December, 1974, there has been an increase in the incidence of acute diarrhoea in the neonatal nurseries of five Melbourne metropolitan hospitals. Four of these have had epidemics, and the incidence of endemic diarrhoeal disease has increased. Extracts of faeces from 148 patients from the five hospitals were examined by electron microscopy. "Duovirus" particles were detected in 82 of these extracts, including at least one from each hospital. No bacterial pathogens were isolated. It seems likely that "duovirus" is an important cause of sporadic and epidemic acute diarrhoeal disease in neonates. It is important to note that the absence of a recognized bacterial pathogen does not exclude an infective cause, especially when sugar intolerance is present. Appropriate measures to minimize the spread of infection must be employed.

Acute Disease↗
PubMed1976

The aetiology of diarrhoea in newborn infants.

Diarrhoea is a common problem in newborn infants in hospital nurseries. In the past, sporadic diarrhoea was often attributed to dietary indiscretion by the mother, and epidemic diarrhoea was though to be caused by an unknown infectious agent. Techniques with which to locate non-cultivable viruses and untypable enteropathogenic strains of Escherichia coli allow reevaluation of the aetiology of diarrhoea in newborn infants. Preliminary results from Melbourne, Australia, suggest that most diarrhoea in newborn infants is induced by a specific infectious agent. During 1975 the agent most often identified from sporadic and epidemic diarrhoea in hospital nurseries was a reovirus-like particle ("duovirus"). Enterotoxin-producing strains of E. coli were rarely isolated. Future attempts to protect newborn infants from developing diarrhoea must be based on an accurate understanding of the aetiology of this disease.

Australia↗
PubMed1976

An enzyme-linked procedure for the detection and estimation of surface receptors on cells.

An enzyme immunoassay procedure has been developed for the visualization and estimation of lymphocyte surface receptors. beta-Galactosidase (beta-gal'ase) was covalently linked to sheep anti-rabbit immunoglobulin (SARIg), to ovalbumin (OA), and to adenosine (A). Exposure of rabbit peripheral lymphocytes to SARIg-beta-gal'ase and subsequent incubation with the fluorogenic substrate fluorescein-beta-digalactopyranoside allowed visualization of B cells by fluorescence microscopy. Treatment with each of the above beta-gal'ase conjugates and incubation with another fluorogenic substrate, 4-methyl-beta-D-umbelliferylgalactopyranoside, made possible the estimation of the various receptors by spectro fluorimetry. Procedures used for enrichment of T and B cell populations could be monitored. Among the findings was that immunoglobulin-bearing cells (presumably B cells) formed rosettes with sheep erythrocytes. The quantitative procedure was used to study lymphocyte population changes during immunization with an A-O A conjugate. An increase in the binding of A-beta-gal'ase, SARIg-beta-gal'ase, and OA-beta-gal'ase by peripheral lymphocytes occurred repeatedly 6 to 8 days after immunization but lasted only a few days despite a continued high circulating antibody titer. These results are consistent with the possibility that immunization induces migration of lymphocytes into the circulation from bone marrow and/or thymus.

Adenosine↗