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Biomedical subjects

M Freeman

Publications and source records attributed to M Freeman.

At least 109 records · Page 6Linked to original sources
PubMed1982

A simple reproducible method for prometaphase chromosome analysis.

A method is described for the analysis of chromosomes in prophase and early metaphase. It involves culturing the lymphocytes in medium RPMI-1640, supplemented with 10% autologous plasma instead of fetal bovine serum. Living cells are treated with actinomycin D and colcemid for 1 h prior to harvest and harvested early at 65 h of incubation, using a hypotonic solution formulated by Ohnuki (1968). The method has been tested on several hundred clinical samples on a routine basis. On average, 30% of the dividing cells were in prometaphase.

Azure Stains↗
PubMed1981

Birth asphyxia. I. Measurement of visual evoked potential (VEP) in the healthy fetus and newborn lamb.

The visual evoked potential (VEP) of five healthy, near-term exteriorized fetal lambs was compared with the VEP obtained from the same animals during the first hour after ventilation. Characteristics of the individual wave components and their relationship to blood pressure, heart rate, and arterial blood gas measurements concomitantly obtained were examined. Results show that the VEP of the healthy fetus is a stable, reproducible signal consisting of four basic components, and that the latencies (msec) and the amplitude (mu V) of the individual components of the VEP are similar to those of the newborn. In two related experiments, fetal asphyxia of unknown duration was encountered during fetal exteriorization an instrumentation. In the first case, neonatal, acidosis persisted despite aggressive resuscitation efforts and was accompanied by an atypical VEP. In the second case, the neonatal VEP obtained after 15 min of resuscitation was markedly depressed despite restoration of acid-base balance but gradually recovered during the remainder of the 1-hr newborn period. In conclusion, the VEP is a reproducible measure of cortical function in the healthy fetus and neonate and may reflect the acute status of cerebral function during fetal asphyxia and neonatal resuscitation.

Animals↗
PubMed1981

Response of children to a single dose of oral or inactivated polio vaccine.

Approximately 200 children aged 8, 12 and 16 years with poliovirus neutralising antibody titres of less than 1/45 to at least one type were given a single dose of oral or inactivated polio vaccine. Almost all children given IPV responded with high levels of neutralising antibody to all 3 types. The response to the oral vaccine was less dramatic. The relationship between pre-existing antibody and the further response and the implications for susceptibility to reinfection will be discussed.

Adolescent↗
PubMed1980

Changes in the vaginal and rectal carriage of group B streptococci during pregnancy.

The group B streptococcus carrier status of pregnant women appears to be relatively unstable. By using multiple low vaginal and rectal samples cultured on 2 or more media, an overall carrier rate of 38% was found in 187 women. Sequential samples commonly showed changes in the nature of the carrier status with time. More carriers were detected late in pregnancy; women giving negative results early in pregnancy often produced positive cultures later and there was a significant tendency towards rectal positivity.

Female↗
PubMed1979

Immunity of children to diphtheria, tetanus, and poliomyelitis.

A survey of titres of diphtheria and tetanus antitoxins and of antibodies to polioviruses in the sera of 291 schoolchildren aged 15, 11, and 7 years showed that high immunisation rates can evoke protective concentrations of tetanus antitoxin in 98% of children and protective levels of the antibodies to diphtheria and all three types of poliomyelitis in 85% of children. Reinforcing immunisation at school entry appeared to be necessary to maintain adequate titres of diphtheria antitoxin in children up to 15 years of age, not essential to maintain adequate titres of tetanus antitoxin, and to have little effect on the titres of antibodies to poliomyelitis.

Adolescent↗
PubMed1978

Training visual-spatial ability in EMR children.

Educable mentally retarded children were randomly assigned to either a visual-spatial training condition or a control group. The children who received training showed a gain from pretest to posttest on the Children's Embedded Figures Test that corresponds to approximately 4 years of maturation in nonretarded children. The performance of the children in the control group on the posttest was not significantly different from their performance on the pretest. Correlations between measures of visual-spatial ability and the employment adjustment of retarded persons obtained by other investigators suggest the potential importance of developing the visual-spatial skills of this population.

Adolescent↗
PubMed1977

Hepatic triglyceride lipase deficiency in liver disease.

The activity of post-heparin lipases in patients with alcoholic hepatitis and viral hepatitis was evaluated. Lipoprotein lipase and hepatic triglyceride lipase were differentiated by assay under high and low salt conditions and also by separation on heparin-agarose affinity chromatography columns. The mean activity of hepatic triglyceride lipase in the sera of liver disease patients was only 21-24% of the mean of controls, but lipoprotein lipase in patients' sera was not different from normal levels. Hepatic triglyceride lipase deficiency may partially account for the accumulation of a triglyceride-rich low density lipoprotein in liver disease.

Alcoholism↗
PubMed1976

The uptake of pyrimidine nucleosides in Tetrahymena. I. Uridine.

Uridine uptake was examined in Tetrahymena pyriformis GL-7 in defined medium under conditions where food vacuole formation is not a significant factor in solute acquisition by the cell. The results indicate the presence of a saturable mechanism which follows Michaelis-Menten kinetics. When corrected for diffusion the apparent Km for the carrier is 2.3 +/- 0.6 muM and the Vmax is 7.3 +/- 0.2 X 10(-7) nmoles/cell/min. It is evident from nucleotide pool analysis that most of the radioactivity of externally supplied [3H]uridine appears in UMP with the remainder in UTP. Uridine is apparently phosphorylated immediately upon entry into the cell and neither uridine-cytidine kinase activity nor RNA synthesis are rate-limiting in the uptake process. Uridine transport is competitively inhibited by a variety of ribo- and deoxyribonucleosides as well as several nucleoside analogs. Neither uracil nor ribose or deoxyribose are effective inhibitors of uridine transport indicating the carrier is specific for the nucleoside. There is little difference between the Ki values for ribo- as opposed to deoxyribonucleosides except in the case of deoxyguanosine which is much less effective as an inhibitor under the conditions of this study, than all the other nucleosides, including guanosine.

Animals↗
PubMed1976

Polymorphism of disopyramide.

Two crystal forms of disopyramide have been characterized using X-ray diffraction, differential scanning calorimetry and infrared spectroscopy. The kinetics of the solid state transformation of Form I to Form II has been analysed using the Prout-Tompkins theory. An activation energy of 144 kJ mol-1 is calculated for the system. Dissolution and plasma concentrations show no significant differences in bioavailability between the two polymorphs.

Biological Availability↗
PubMed1975

The cytogenetic structure of Tasmanian populations of Phaulacridium vittatum.

In 8 out of 20 Tasmanian populations of Phaulacridium vittatum from 0.3-11.0 percent of the males carried a single supernumerary chromosome. In such males the X and B univalents are both heteropycnotic at first prophase of male meiosis and associate with another in a non-homolgous manner in about two-thirds of the diplotene cells examined. In all 56 B-containing individuals studied, however, these associations lapse by first metaphase and the X and the B move at random with respect to one another at first anaphase. The supernumerary in this species is stable and only 5 of the 56 individuals with supernumeraries showed evidence of B-chromosome non-disjunction in the pre-meiotic mitoses. Since there was no other evidence for the loss or gain of supernumeraries in the male line it is clear that B-transmission is regular in the males of this species. There were significant differences between population with respect to mean cell chiasma frequency but there was no significant effect of the B-chromosome on this metric. Additionally a comparison of mean cell chiasma frequency in follicles with and without supernumeraries from a mosaic individual shows no significant difference.

Animals↗
PubMed1975

Causes and consequences of Robertsonian exchange.

At least two types of Robertsonian exchange are now known in the acrocentric chromosomes of man. Both types involve breakage in the arms adjacent to the centromere. Evidence is presented for a third type of exchange, one involving breakage within the centromere itself, in the grasshopper Percassa rugifrons. In this species, which is regularly homozygous for a single fusion metacentric, the eighteen rod autosomes have small but pronounced granules at the centric end of the chromosome. When C-banded these granules show differential Giemsa staining and appear to represent centromeric chromomeres; these chromomeres are lacking in the metacentric fusion product. Equivalent fusions may have occurred in some mammal species too and possible examples of this are discussed in sheep and mice. The Percassa fusion has led to a modification in both the frequency and the distribution of chiasmata as judged by a comparison of these properties in the metacentric relative to the two next smallest rod equivalents. Comparable modifications are known to occur in other naturally occurring fusions but these changes are certainly not automatic consequences of fusion since they are not shown in at least some newly produced fusion mutants.

Animals↗