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Biomedical subjects

D G Young

Publications and source records attributed to D G Young.

At least 55 records · Page 3Linked to original sources
PubMed1988

Interleukin-1 injected into mammalian brain stimulates astrogliosis and neovascularization.

Interleukin-1 (IL-1), a protein produced by mononuclear phagocytes, helps to initiate the inflammatory response through its action upon a diverse population of cells. Recently this immunomodulator has been detected at sites of traumatized brain. As reported here, recombinant forms of IL-1 injected into the cerebral cortex of adult rats elicit not only astrogliosis but also new blood vessel growth. These responses are typical of brain injury and suggest that IL-1-secreting inflammatory cells may mediate wound healing in the CNS.

Animals↗
PubMed1988

Brain cell karyotypes of six new world sand flies (Diptera: Psychodidae).

The brain cell karyotypes of six New World sand flies are described and compared. Lutzomyia trapidoi has three pairs of chromosomes, 2N = 6. The other species, L. gomezi, L. erwindonaldoi, L. carmelinoi, L. walkeri and L. columbiana, have four pairs of chromosomes, 2N = 8. No heteromorphic chromosomes were observed. Cytogenetic similarities among sand fly species are discussed.

Animals↗
PubMed1988

Interleukin-1 is an astroglial growth factor in the developing brain.

The immunomodulator interleukin-1 (IL-1) is found to be an astroglial growth factor during development of the mammalian brain. In vitro studies indicate that ameboid microglia, a class of brain mononuclear phagocytes, are the likely source of IL-1. Examination of different brain regions during development shows IL-1 production only after the appearance of ameboid microglia. These observations suggest that brain mononuclear phagocytes secrete growth factors that regulate normal growth and development of the CNS.

Animals↗
PubMed1987

Surgery for necrotizing enterocolitis.

Thirty-seven patients who had necrotizing enterocolitis and required emergency surgical intervention are reviewed. The indications for surgery were intestinal perforation (28), intestinal obstruction (7), clinical deterioration (1) and persistent rectal bleeding (1). The initial procedure was percutaneous peritoneal catheter drainage (13), intestinal diversion alone (8), intestinal resection (14), laparotomy and biopsy (1) and laparotomy alone (1). Twelve patients developed late intestinal strictures. The overall mortality rate was 35 per cent.

Age Factors↗
PubMed1987

Long-term follow-up of surgical renal hypertension.

A retrospective study of 42 children with hypertension secondary to renal disease is presented. Thirty-three had scarred kidneys, 5 had renovascular disease, 2 had renal venous thrombosis, 1 had an angiomatous malformation of the upper pole of the kidney, and 1 had glomerulonephritis. Twenty-six children were managed surgically. The etiology, presentation, and management are presented. Follow-up varied from 2 to 14 years and the outcome is discussed.

Adolescent↗
PubMed1987

CHARGE association in neonates presenting with choanal atresia.

Ten infants presented with choanal atresia. Four showed 4 or more components of CHARGE association, 3 of whom died before the age of 2 months while infants with choanal atresia but not having other features of CHARGE association survived. The combination of choanal atresia and heart disease carries a very high risk.

Abnormalities, Multiple↗
PubMed1987

The partially diabetic pancreas: a histological study of a new animal model.

An animal model in which part of the pancreas was made diabetic due to almost total loss of insulin-secreting B cells, while the remainder of the gland remained normal, is described. In rabbits, a vascular clamp was placed across the junction of the body and tail of the pancreas, thus occluding the circulation to the tail. Alloxan (200 mg/kg) was injected i.v., and 4 min later dextrose (0.5 g/kg) was given by the same route. After a further 2 min the clamp was removed. Thirty-four animals were studied, 17 of which died in the first postoperative week of surgical complications or of alloxan-induced toxicity to the liver and kidneys. The survivors were killed between 4 and 12 weeks after surgery and were not metabolically diabetic. They had a virtually complete absence of B cells but a normal population of A, D, and PP cells in the head and body of the pancreas. The islets in the tail of the pancreas appeared entirely normal. This model appears suitable for studying the effects of locally produced insulin on pancreatic exocrine function in metabolically normal animals.

Alloxan↗
PubMed1987

Natural infection of humans, animals, and phlebotomine sand flies with the Alagoas serotype of vesicular stomatitis virus in Colombia.

Five isolations of the Alagoas serotype of vesicular stomatitis virus (Rhabdoviridae: Vesiculovirus) were made from naturally infected phlebotomine sand flies (Lutzomyia spp.) collected in Colombia. These are the first isolations of Alagoas virus from an arthropod. Replication of the virus occurred in laboratory-reared sand flies (Lutzomyia longipalpis) after inoculation. Bite and transovarial transmission of the virus was also demonstrated in experimentally infected sand flies. Alagoas virus neutralizing antibodies were found in sera of humans and animals living near the insect collection site; antibody rates among human residents of two nearby towns were 63% and 83%, respectively. Results of comparative serologic studies demonstrated that Alagoas virus is closely related antigenically to Indiana, Cocal, and Maraba viruses and that these four agents form a complex within the vesicular stomatitis virus serogroup. The antigenic similarity among these four viruses makes their differentiation difficult; it also raises doubts about the accuracy of current laboratory methods used for identifying isolates in this serogroup. A discussion follows on the significance of human antibodies to these agents and on the role of sand flies in their ecology.

Animals↗
PubMed1987

Experimental transmission of Plasmodium mexicanum by bites of infected Lutzomyia vexator (Diptera: Psychodidae).

Lutzomyia vexator is an efficient experimental vector of Plasmodium mexicanum, infecting 69.2% (9/13) of the Sceloporus undulatus lizards with as few as one bite. Sporozoites were present in the salivary glands by day 6.5 postfeed and infective by day 8 postfeed at 27 degrees C. The prepatent period was relatively long, ranging from 23 to 40 days for bite-induced infections and appears to be related to the number of sporozoites injected. The acute phase of the infection is initially exponential and rapid. All lizards (6) that were not sacrificed, died of fulminating infections from 13 to 56 days after parasites were seen in the blood films. Gametocytes from 2 experimentally infected lizards were infective to L. vexator during the course of the acute infection. The majority of P. mexicanum parasites were in erythrocytes of Sc. undulatus. Exoerythrocytic forms were observed in circulating lymphocytes and thrombocytes, lymphocytes of spleen and bone marrow, and endothelial cells of brain capillaries.

Animals↗
PubMed1987

Vector incrimination and experimental transmission of Plasmodium floridense by bites of infected Culex (Melanoconion) erraticus.

A survey of mosquitoes which are attracted to and readily feed upon lizards in a northcentral Florida area where there is a relatively high prevalence of Plasmodium floridense in Anolis carolinensis was conducted. Culex erraticus and Cx. territans, collected in lizard-baited traps, readily fed on lizards in the traps and in the laboratory, and the former mosquito species is an experimental vector of Plasmodium floridense. Sporozoites were observed in the salivary glands from 11 to 14 days at 21-25 degrees C following an infective blood meal. The prepatent period of P. floridense in A. carolinensis at 18-24 degrees C was relatively long, 24-25 days (n = 2). At 32 degrees C, the prepatent period was decreased to 13-17 days (n = 4). The transmission rate of P. floridense by bite of Cx. erraticus and intraperitoneal inoculation of sporozoites from the salivary glands of Cx. erraticus, was relatively low (16.2%). Peak parasitemias ranged from 912 to 4,280 parasites per 10,000 red blood cells. Sporogonic development of P. floridense in Cx. territans which fed on infected lizards was not observed.

Animals↗