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Biomedical subjects

L Melton

Publications and source records attributed to L Melton.

22 records · Page 2Linked to original sources

Prenatal cocaine exposure and school-age intelligence.

Assessments of the possible consequences of prenatal exposure to cocaine have been limited by lack of control for socio-demographic confounders and lack of follow-up into the school years. We evaluated intelligence at ages 6-9 years in 88 children from a cohort of 280 born between September 1, 1985 and August 31, 1986 and identified at birth as cocaine-exposed, and in a group of unexposed (n = 96) births of comparable gender and birthweight. IQ scores did not differ between children with and without prenatal exposure to cocaine (mean 82.9 vs. 82.4, difference = 0.5 points, 95% CI-3.1, 4.1); results were unchanged with adjustment for child height, head circumference and prior residence in a shelter or on the street, and for caregiver IQ and home environment (mean difference = 2.2 points, 95% CI-1.5, 5.8).

Black or African American↗

Enhancement of survival from murine polymicrobial peritonitis with increased abdominal abscess formation.

Muramyl dipeptide (MDP), a purified synthetic immune adjuvant, has been shown to increase murine intraabdominal abscess formation in a monomicrobial model using Bacteroides fragilis. This effect required live bacteria and was abolished by appropriate antibiotics. A polymicrobial model of peritonitis and abdominal abscess formation using Streptococcus fecalis, Escherichia coli, and B. fragilis was initially used to determine mortality rates at various concentrations and obtain an appropriate LD50. Animals were then pretreated with MDP or its inert buffer and underwent intraperitoneal injection of the appropriate bacterial suspension. Mortality and abdominal abscess formation were then assessed at 2 weeks after injection. There was a significant reduction in mortality (P less than 0.03) in mice treated with MDP compared to the controls. In surviving animals, there was also a significant increase in the number of animals forming abscesses (P less than 0.05) following treatment with MDP. This study has shown that nonspecific immune stimulation by MDP provided enhanced protection against a polymicrobial intraperitoneal challenge and paradoxically increased the formation of abdominal abscesses at the same time. This may be regarded as enhancement of the natural history of survival from peritonitis via bacterial containment through intraabdominal abscess formation, a manifestation of beneficial outcome in experimental peritonitis.

Abdomen↗

Stimulatory effects of muramyl dipeptide upon neutrophils isolated from a local bacterial infection.

This study examined the effects of muramyl dipeptide (MDP) in vivo upon the local inflammatory response to a bacterial challenge. In addition to quantitative bacteriology of the tissues surrounding an infected suture, polymorphonuclear leucocytes (PMN) involved in the local inflammatory response were extracted and estimations made of their number, viability and phagocytic activity. Fewer bacteria were recovered from the muscle around the suture in MDP-treated animals compared to placebo-treated controls (P less than 0.02), although there was no difference in the number of bacteria on the suture itself. Polymorphonuclear leucocytes were present in greater numbers (P less than 0.01), more PMNs were viable (P less than 0.01) and more PMNs had visibly phagocytosed bacteria (P less than 0.01) in the MDP group compared to the placebo group. These data indicate that MDP enhances the local inflammatory response to infection with increased influx, viability and phagocytic activity of PMNs, resulting in improved local control of a test bacterial challenge.

Acetylmuramyl-Alanyl-Isoglutamine↗