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Biomedical subjects

D Major

Publications and source records attributed to D Major.

At least 37 records · Page 2Linked to original sources
PubMed1989

Influenza A (H1N1) vaccine efficacy in animal models is influenced by two amino acid substitutions in the hemagglutinin molecule.

The immunogenicity and protective efficacy of formalin-inactivated vaccines prepared from influenza A (H1N1) viruses grown in MDCK cells and in eggs was compared in animal models. The A/Chr/157/83 virus grown in MDCK cells (157M) differed by two amino acid substitutions in the HA molecule from the corresponding virus grown in eggs (157E) and the two viruses could be distinguished antigenically by monoclonal and polyclonal antibodies. Following two intramuscular injections of vaccine in ferrets, guinea pigs, and hamsters, both vaccines were equally immunogenic when antibody was analyzed by hemagglutination inhibition using homologous virus. However, single radial hemolysis analysis following antibody cross-adsorption showed that antibody stimulated by 157E vaccine was exclusively strain specific whereas that produced by the 157M vaccine was more broadly reactive. When immunized hamsters were challenged with virus cultivated on mammalian (MDCK) cells, the homologous vaccine induced a higher degree of protection than the corresponding egg-grown vaccine.

Amino Acid Sequence↗
PubMed1989

[Congenital diaphragmatic hernia. Therapeutic re-evaluation].

Twenty-eight patients with "High-Risk" diaphragmatic hernia were treated without postoperative ipsilateral chest drains. Overall survival was 71%. This study suggests that, in cases of complete absence of the diaphragm, the use of a mesh pervious to air is as noxious postoperatively as an underwater chest drain. This idea is supported by experiments in cats with a left pneumonectomy, in which part of the diaphragm was replaced either by a macroporous mesh or by a microporous prosthesis impervious to air at normal pressures. Moreover, barotrauma may occur preoperatively and when assisted ventilation is required, inspiratory pressure must be strictly limited.

Animals↗
PubMed1987

Pulmonary barotrauma in congenital diaphragmatic hernia: experimental study in lambs.

A left diaphragmatic hernia was created surgically in 20 fetal lambs between 93 and 110 days of gestation. Ten animals were alive with defects at cesarean section near term (135 to 140 days). These animals and two controls were submitted to various transpulmonary pressure gradients (inspiratory pressure minus pleural pressure). Hemodynamic and ventilatory studies were performed after the correction of the hernia. Morphometric analysis of the lung was carried out in all cases. The results showed a highly significant linear correlation between the transpulmonary pressure gradient employed and the pulmonary interstitial emphysema found at morphometry. Our data suggest that using low ventilatory pressures and not draining the pleural cavity results in less trauma to both lungs and may prevent one of the components of the pulmonary hypertension so often seen in newborns with congenital diaphragmatic hernia.

Animals↗
PubMed1987

Serological studies with influenza A(H1N1) viruses cultivated in eggs or in a canine kidney cell line (MDCK).

Pairs of influenza A(H1N1) viruses cultivated from the same clinical specimen in canine kidney (MDCK) cells or in embryonated hens' eggs can frequently be distinguished by their reactions with monoclonal antibodies to haemagglutinin and with antibodies in ferret or human sera. Egg-adapted virus, further passaged in MDCK cultures remained "egg-like" in serological characteristics indicating that the differences in their serological reactions were not a direct result of host cell-dependent glycosylation of the haemagglutinin. Haemagglutination-inhibiting (HI) or virus neutralizing antibodies in human sera can be detected more frequently, and to higher titre, in tests employing virus grown exclusively in MDCK cells than in tests with virus adapted to growth in embryonated eggs. Striking differences were detected in the serological reactions in HI tests when sera from ferrets infected with egg-grown virus were tested against a series of strains of influenza A(H1N1) virus isolated in 1983 and adapted to growth in eggs. In contrast, sera from ferrets infected with MDCK-derived virus failed to distinguish serologically between the same viruses that had been passaged exclusively in MDCK cells and also revealed relatively small differences between their egg-adapted counterparts.It was concluded that the cell substrate used for virus isolation and cultivation is a factor that should be considered when interpreting the results of strain characterization of influenza A(H1N1) isolates and in sero-surveys using these viruses.

Influenza A Virus, H1N1 Subtype↗
PubMed1986

Biochemical and antigenic analysis using monoclonal antibodies of a series of of influenza A (H3N2) and (H1N1) virus reassortants.

Reassortant influenza A viruses with high growth capacity in eggs and suitable as candidate vaccine strains or as standard reagents for influenza HA quantification were prepared using the high yielding A/PR/8/34 (H1N1) as one parent and a number of 'wild' strains of influenza A (H1N1) or (H3N2) viruses as the other parent. The genetic and antigenic composition of the reassortants was determined. The parental derivation of genes in the reassortants was established by electrophoretic analysis of virus RNA and virus induced polypeptides. The haemagglutinin (HA) antigens of the three H1N1 viruses (NIB-6, NIB-7 NIB-12) were found to resemble those of the parental viruses when tested against a panel of monoclonal antibodies and using the HI test. A similar correspondence between the antigenic characteristics of the HA of the influenza A (H3N2) reassortants (NIB-1, NIB-4, NIB-5, NIB-8 and NIB-11) and parental viruses was noted. Therefore laboratory manipulations to produce the reassortants did not result in the selection of significant antigenic variants.

Animals↗
PubMed1984

The effect of nitrous oxide on the oxyhaemoglobin dissociation curve.

The influence of nitrous oxide on the oxyhaemoglobin dissociation curve (ODC) was studied using blood from twenty healthy patients. When the blood samples were exposed to 50 per cent N2O during the determination of the ODC, a left shift was observed and the P50 was decreased by 1.06 kPa (8 mmHg). This shift cannot be explained by temperature, pH, PCO2, or 2,3-DPG effects. Following exposure of the blood to N2O-free gases, the shift disappeared rapidly, and a normal P50 (3.46 kPa) (26 mmHg) was reobtained. In keeping with this reversibility, blood samples taken before and during 45 minutes of N2O-curare anaesthesia showed identical dissociation curves to those which had been obtained during the in vitro N2O exposure experiment.

2,3-Diphosphoglycerate↗
PubMed1982

Evidence for discrete cell kinetic subpopulations in mouse epidermis based on mathematical analysis.

Continuous (repeated) labelling studies in mouse epidermis indicate that nearly all cells are labelled after about 100 hr. Percentage labelled mitoses studies ([3H]TdR at 15.00 and 03.00 hours) have a first peak that does not reach 100% and has a half-width of about 10 hr. Small second and third peaks can be detected at about 90 and 180 hr. respectively. The changes with time in the number of labelled cells show a difference dependent on the time of day of [3H]TdR administration. Both curves show an early doubling in labelled cells which then decline, forming a peak of labelled cells. A second peak occurs at about 120 hr. This is followed by a progressive decline with no further peak until values of about 1% labelling are obtained at 340 hr. These experiments have been investigated mathematically. A computer programme has been devized that permits all three types of experiments to be analyzed simultaneously. More importantly, it can analyse situations with a heterogeneity in cell cycle parameters in all proliferative subpopulations. Various models for epidermal cell replacement have been considered. The data as a whole can best be explained if the basal layer contains at least two distinct subpopulations of cells and an exponentially decaying post-mitotic population with a half-life of about 30 hr. The proliferative sub-populations must be characterized by near integer differences in the length of cycle, the precursor (stem) compartment having the longer cycle. An inverse relationship is required for the length of S, i.e. the shortest time for the stem cells. A full range of cell kinetic parameters can be calculated and are tabulated for the most appropriate model system which is one involving three transit proliferating subpopulations.

Animals↗
PubMed1981

Paris for two.

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History of Medicine↗