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Biomedical subjects

M G MacDonald

Publications and source records attributed to M G MacDonald.

At least 19 recordsLinked to original sources
PubMed1994

Persistent pulmonary hypertension in newborn infants with cogenital myotonic dystrophy.

We describe two infants with congenital myotonic dystrophy that was complicated by persistent pulmonary hypertension. Both infants died of respiratory insufficiency that was unresponsive to ventilatory and pharmacologic support. One of the two infants was supported with extracorporeal membrane oxygenation before the diagnosis of congenital myotonic dystrophy was made.

Extracorporeal Membrane Oxygenation↗
PubMed1990

Cerebrospinal fluid and plasma beta-endorphin-like immunoreactivity in full-term neonates and in preterm neonates with and without apnea of prematurity.

Beta-endorphin-like immunoreactivity (B-ELI) was measured in cerebrospinal fluid (CSF) and plasma from infants of postnatal age 24 h to 70 days. Three groups were examined: 17 were of postconceptual age greater than or equal to 37 weeks, 16 were postconceptual age less than or equal to 35 weeks without apnea and 10 were of postconceptual age less than or equal to 35 weeks with apnea. All infants were clinically stable. Two-way analysis of variance between groups showed no difference in the concentration of B-ELI in CSF or plasma, or in the CSF/plasma B-ELI ratio. Concentrations of B-ELI in plasma were significantly higher in infants of postnatal age 1-3 weeks and greater than or equal to 4 weeks, than in infants of postnatal age less than 1 week. We conclude that, in nonstressed infants, there is no relationship between the concentration of B-ELI in CSF or plasma and a concurrent diagnosis of apnea of prematurity. Our data indicate that a significant developmental increase occurs in the plasma concentration of B-ELI after the first week of life.

Aging↗
PubMed1987

Low incidence of acquired cytomegalovirus infection in neonates transfused with washed red blood cells.

To define the incidence of cytomegalovirus (CMV) infection in infants given transfusions of washed blood cells from random donors, 100 infants who were identified as being CMV seronegative at birth were resampled at hospital discharge and again six weeks after hospitalization. All infants received washed red blood cell products; 37 infants received nonleukodepleted platelets and/or plasma. There were 7.4 donor exposures per infant. Donor units were assayed for anti-CMV IgG and IgM at the time of donation. Seventy-six infants received at least one transfusion from a seropositive donor (mean transfusion volume, 89 mL; mean, 3.7 seropositive donor exposures). Infection was defined by seroconversion to anti-CMV. None of the recipients of exclusively seronegative blood seroconverted. A single infant who received 34 mL of washed cells from a seropositive donor (IgG+, IgM-) and 31 mL of washed cells from a seronegative donor showed IgM anti-CMV 15 days after transfusion and IgG anti-CMV at a six-week follow-up visit. No recipients of IgM+ blood were infected. Our data demonstrate a 1.3% incidence of anti-CMV seroconversion following receipt of washed red cells from seropositive donors. This rate is within background levels for hospitalized neonates and is significantly lower than results of similar studies using unwashed blood.

Antibodies, Anti-Idiotypic↗
PubMed1987

AIDS, HTLV-III diseases, minorities and intravenous drug abuse.

Minorities and women who are engaging in activities which place them at high risk for infection with HTLV-III are developing HTLV-III related illnesses including AIDS. In Northeastern urban areas the relatively large number of minorities who use intravenous drugs are responsible for producing large numbers of patients with AIDS (PWAs). Eighty percent of heterosexual male and female PWAs are Black or Hispanic. The development and implementation of effective prevention and education programs for these individuals rests upon an understanding of the less traditional approaches which may be necessary to reach these groups. The general public must be made aware of the hazards of HTLV-III related diseases and that the risk of infection is restricted to very well defined high risk groups. Minorities must be made to understand that they are at increased risk for HTLV-III related diseases only because of the high incidence of drug abuse in their community.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Effect of naltrexone on apnea of prematurity and on plasma beta-endorphin-like immunoreactivity.

Plasma levels of beta-endorphin-like immunoreactivity (beta-ELI) were measured in premature infants with apnea (n = 11) and compared to those in nonapneic controls (n = 9). Naltrexone (1-3 mg/kg) was given to the infants with apnea, 6 of whom were also receiving methylxanthines. Chest wall movements, nasal airflow, transcutaneous PO2 and electrocardiogram were recorded for 4-6 h prior to and for 4-6 h after administration of naltrexone. Samples for beta-ELI were taken prior to and 1 h post naltrexone. beta-ELI levels were significantly higher (p less than 0.007) in infants with apnea of prematurity than in control infants. No significant difference was found in beta-ELI levels before and after naltrexone. Naltrexone did not decrease the incidence of apnea.

Apnea↗
PubMed1986

Preventing complications from lines and tubes.

Rather than providing an exhaustive list of known complications of all tubes and lines used in the NICU, we have highlighted the potentially traumatic nature of their use and outlined general principles of prevention. Most complications of care are more easily avoided if we know about them in advance. Attention to simple details, while recognizing that use of indwelling tubes and lines has both benefits and hazards, should lessen some of these morbidities.

Catheterization↗
PubMed1985

HTLV-III exposure among drug users.

The Centers for Disease Control hierarchical classification of those at risk for acquired immunodeficiency syndrome (AIDS) underestimates the number of cases in which illicit drug use may play a role in the exposure to human T-cell leukemia virus type III. The immunosuppressive effects of nitrite inhalants are not sufficiently documented to elucidate their role as a cofactor in the development of AIDS. The currently available data on the immunosuppressive effects of self-administered parenteral drugs and their diluents indicate an associated elevation of immunoglobulin M, depressed helper/suppression T-cell ratios, and even damage to DNA. Illicit psychoactive drugs and their diluents may influence the virulence of the virus among parenteral drug users. An association between parenteral drug use and prostitution is not unexpected. Female prostitutes who use parenteral drugs may be at high risk for exposure to the virus and thus may transmit this infectious agent to their clients and their families.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Potentiation of the toxic effects of acetaminophen in mice by concurrent infection with influenza B virus: a possible mechanism for human Reye's syndrome?

Using weanling mice of two different genetic strains we demonstrated a potentiation of the toxic effects of acetaminophen by prior infection with influenza B virus. The C57BL/6N (B6) strain of mice is genetically predisposed to increased toxicity from acetaminophen when the hepatic cytochrome P-450 mixed function oxidase system is preinduced. When B6 animals are pretreated with influenza B virus and an mixed function oxidase system inducing agent before administering acetaminophen, we observed a significant incidence of atypical "fatty" liver pathology on light microscopy similar to the microvesicular steatosis seen in human Reye's syndrome. Electron microscopic changes in the liver of these animals resemble those published to date in human Reye's syndrome.

Acetaminophen↗
PubMed1981

Development of the hepatic mixed-function oxidase system and its metabolism of warfarin in the perinatal rat.

The development of the rat hepatic microsomal mixed-function oxidase system was investigated by analyzing its components in fetal and young pups of postconceptional age 18-54 days. Cytochrome P-450 and cytochrome b5 concentrations and NADPH-cytochrome c reductase and R-warfarin hydroxylase activities were determined as a function of postconceptional age. The cytochromes and reductase were present and increased with age before birth, and major increases were detected in the first 2 days after birth. The cytochrome P-450 concentration increased again markedly at puberty, whereas reductase activity increased before puberty and reached the adult level at puberty. Metabolism of warfarin to specific metabolites indicated that at 37 days postconception the isozyme cytochrome P-450 UT-C began to predominate. Its domination of the hepatic cytochrome P-450 pool increased with age.

Aging↗
PubMed1977

Correlation of cord bilirubin levels with hyperbilirubinaemia in ABO incompatibility.

We studied 91 offspring of ABO incompatible preganacies and 30 controls resulting from O--O pregnancies to test whether cord bilirubin levels could be used to predict the severity of hyperbilirubinaemia in ABO incompatibility. Blood group, direct Coombs's test, and serum bilirubin estimations were carried out on cord blood, and bilirubin estimations at 12, 24, 36, and 48 hours of life.

ABO Blood-Group System↗