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Biomedical subjects

J James

Publications and source records attributed to J James.

At least 163 records · Page 9Linked to original sources
PubMed1984

Ultrastructural changes in rat liver sinusoids during prolonged normothermic and hypothermic ischemia in vitro.

By means of electron microscopic analysis of liver fragments incubated in an air-tight wrapping (in vitro ischemia), the following facts have been established with regard to the development of signs of irreversible damage in cells from the sinusoidal wall compared with hepatocytes. With normothermic (37 degrees C) in vitro ischemia, signs of irreversible damage appeared in cells of the sinusoidal wall at a a much earlier stage than in hepatocytes (60-90 min and 90 min-2 h respectively). With in vitro ischemia in the cold (4 degrees C), these differences were even more marked; irreversible cell damage was apparent after between 24 and 36 h incubation in endothelial cells, whereas in hepatocytes flocculent densities followed by other signs of irreversible damage were found only after 79 h incubation. These findings are discussed in relation to the 'no reflow' phenomenon after ischemia in general. The rule that changes in the vascular system following ischemia may well obscure the actual sensitivity of parenchymal cells is particularly applicable to the liver. Attempts to lengthen the period of ischemia which 'liver tissue' can stand for example, with a view to transplantation, attention should be focussed primarily on the events in the sinusoidal wall.

Animals↗
PubMed1984

Latamoxef and the newborn.

Thirty one preterm neonates who had clinical, radiological, or bacteriological evidence of infection and who would normally have received gentamicin and penicillin were treated with latamoxef (Moxalactam) 100 mg/kg/day. All were examined prospectively for clinical improvement and possible side effects. Biochemical and haematological values were monitored and pharmacokinetic variables determined. Thirty babies improved during treatment; latamoxef was effective in eradicating the infecting organisms in 7 of 9, including three babies infected with Lancefield group B streptococci. High serum concentrations of latamoxef were achieved after either intravenous or intramuscular administration and accumulation did not occur. Treatment had no effect on renal or hepatic function nor did it result in increased serum values of non-protein bound bilirubin. Clotting studies, where performed, were normal and no babies had bloody stools. Two disulfiram-like reactions were recorded. Latamoxef proved a safe and efficacious alternative to gentamicin with penicillin in the initial treatment of neonates with clinical evidence of infection.

Bacterial Infections↗
PubMed1984

Glucose-6-phosphate dehydrogenase activity in individual rat hepatocytes of different ploidy classes. I. Developments during postnatal growth.

The glucose-6-phosphate dehydrogenase (G6PDH) activity of isolated male rat hepatocytes has been investigated in relationship to the ploidy classes of the cells during the first 20 weeks of postnatal growth. The G6PDH activity in the individual cells was measured with an improved quantitative cytochemical method. The data obtained showed that throughout the whole period of postnatal growth there existed a proportional relationship between the genome copies per cell and the amount of G6PDH activity per cell for binuclear diploid (BD), mononuclear tetraploid (MT) and binuclear tetraploid (BT) cells but not for mononuclear diploid (MD) cells. In the MD cells, which are the stem cells of the liver parenchyma, the activity measured was 1.5 times higher than expected. Furthermore, during postnatal growth, the G6PDH activity per hepatocyte was low at the age of 2 weeks, increased somewhat after weaning (5 weeks) and then more dramatically after 8 weeks to reach a maximum between 12 and 16 weeks. This development occurred in MT and BT cells at an earlier age than in MD and BD cells, in which the increase in enzyme activity followed some 3 weeks later. Castration of the rats before puberty did not influence the development of the amount of G6PDH activity per cell of any of the ploidy classes.

Animals↗
PubMed1983

Investigation of the mechanism of cadmium toxicity at cellular level. I. A light microscopical study.

Chromatin condensation occurs within 15 min to 1 h after the addition of CdCl2 in a concentration of 1 microgram/ml to a liver cell culture and seems to be the first event demonstrable by light microscopy. This chromatin condensation, which precedes membrane leakage, is irreversible and leads to cell death of almost all cells. It does not occur after the administration of equimolecular concentrations of some other bivalent metallic ions.

Animals↗
PubMed1983

The value of enzyme leakage for the prediction of necrosis in liver ischemia.

Following the clamping of the afferent vessels of the left lateral and median lobes in rat liver, a considerable part of these lobes show signs of necrosis 24 h after 90 min of ischemia, whereas no necrotic areas can be detected after 30 min interruption of the blood flow. The purpose of this study was to examine the value of an analysis of the leakage of enzymes from the liver parenchyma in the early phase after restoration of the blood flow after ischemia for a prediction of the occurrence of necrosis. Leakage of the enzymes GPT, GOT and LDH can be detected in the blood plasma with a maximum activity between 1 and 5 h both following 30 and 90 min of ischemia; a considerable difference in clearance is observed, however, in the period afterwards, the normal situation being reached after 24 h with the 30-min ischemic period, but not following the 90-min period. With use of an enzyme histochemical reaction, in situ a depletion of LDH-activity in the hepatocytes could be detected within a short period of time after 30 min temporary ischemia and a restoration during the following period of 24 h; the decrease in LDH-activity persisted during 24 h with a 90-min period of ischemia. Electronmicroscopically cytoplasmic blebs arisen from hepatocytes are observed in the lumen of sinusoids immediately after 30 min of ischemia, whereas after 90 min of ischemia actual leakage of cytoplasmic material takes place through the damaged surface of the hepatocytes. Enzyme leakage probably takes place via these both types of shedding of cytoplasm. It is concluded that the enzyme leakage as such cannot be used as a discriminating test between reversible and irreversible damage of the liver parenchyma.

Alanine Transaminase↗
PubMed1983

Cuprolinic Blue: a specific dye for single-stranded RNA in the presence of magnesium chloride. II. Practical applications for light microscopy.

The application of the new nucleic acid dye Cuprolinic Blue to cell smears and tissue sections has been described. Without added cations, Cuprolinic Blue stains both DNA and RNA, whereas in the presence of 1 M MgCl2, Cuprolinic Blue specifically stains single-stranded RNA only. The total RNA can be stained after removal of DNA by DNAase digestion. Fixation in a modified Carnoy solution gave optimal staining results in all cases tested. By cytophotometry, a reliable and reproducible relative estimate can be obtained of the total nucleic acid content, the total RNA content and the amount of single-stranded RNA alone per cell.

Animals↗
PubMed1983

Chronic myelogenous leukemia with a Philadelphia chromosome resulting from a complex translocation (2; 9; 22), following an undifferentiated acute leukemia.

This case report concerns a patient with acute leukemia considered at diagnosis to be undifferentiated. Unfortunately, because of the failure of the culture, a cytogenetic evaluation was not possible at that stage. A full remission was induced, but 17 months after the onset of the disease the patient developed chronic myelogenous leukemia. The karyotypes prepared at that time and during the follow-up revealed the presence of a Philadelphia chromosome (Ph1) in all examined cells. This Ph1 resulted from a complex translocation involving chromosomes No. 2, 9, and 22.

Adult↗
PubMed1983

A time-dependent distribution pattern of ploidy classes in adult rat liver parenchyma.

The distribution pattern of rat liver parenchymal cells of different ploidy classes has been investigated with isolated liver cell preparations on four different time points of the day. The percentage distribution of different ploidy populations was found to fluctuate along the activity-rest cycle of the animals. The mononuclear tetraploid (MT) cell population showed the strongest time-dependent distribution pattern with a 10% variation around the 24 h mean, the variations in the binuclear diploid (BD) cells being somewhat less obvious, but clearly present. The mononuclear diploid cells and the binuclear tetraploid cells occurred in a virtually constant percentage. An inverse correlationship was noted between MT and BD cells, the increase in the number of MT cells being accompanied by a decrease in the number of BD cells. This interdependency in the presence of the two cell types can be related to their relationship in the process of formation.

Animals↗
PubMed1982

A sensitive cytochemical staining method for glucose-6-phosphate dehydrogenase activity in individual erythrocytes. I. Optimalization of the staining procedure.

A sensitive cytochemical staining method for glucose-6-phosphate dehydrogenase activity in individual human erythrocytes is described. This staining method can be used for the rapid routine discrimination of patients with a deficiency of the enzyme in its homozygote or heterozygote form, but also for quantitative localization of its activity in individual erythrocytes. The staining procedure in its optimal form consists of a treatment of the erythrocytes with sodium nitrite, then a "fixation" in 0.025% glutaraldehyde (under NADP+ protection of the active site of the enzyme), followed by incubation of the cells in suspension in the presence of tetranitro BT, 1-methoxyphenazine methosulphate and polyvinyl alcohol. Using this new technique, a sharp localization is obtained of the glucose-6-phosphate dehydrogenase activity, which enables discrimination between red cells with different levels of enzyme activity, as a consequence of enzyme deficiencies or age changes.

Erythrocytes↗
PubMed1982

On the DNA content and ploidy of trypanosomes.

We have determined the nuclear and kinetoplast DNA content of two trypanosomatids by quantitative absorption and fluorescence cytophotometry of individual Feulgen-pararosaniline stained cells. For the insect trypanosomatid Crithidia fasciculata we find nuclear and kinetoplast DNA contents of 0.095 and 0.032 pg per non-replicating cell. For the African trypanosome Trypanosoma brucei these values are 0.097 and 0.004 pg. A sub-population of T. brucei cells with two kinetoplasts and one nucleus was found to contain 0.181 pg/nucleus. The DNA values of bloodstream form T. brucei and the procyclic culture from were not significantly different. In DNA-DNA renaturation experiments the haploid amount of DNA in T. brucei was previously found to be 0.041 pg/nucleus (Borst, P., Fase-Fowler, F., Frasch, A.C.C., Hoeijmakers, J.H.J. and Weijers, P.J. (1980) Mol. Biochem. Parasitol. 1,221-246). Our data, therefore, indicate that T. brucei is diploid. No sub-population of haploid cells was observed in T. brucei grown in rats or in culture.

Animals↗
PubMed1982

A model for provoking ischemic necrosis in rat liver parenchyma and its quantitative analysis.

Ischemia in the left lateral and median lobe of the rat liver was provoked by means of a small clip, as applied in human microvascular surgery. After various periods of ischemia (30, 40, 50, 60 and 90 min) the blood flow to these lobes was restored. Twenty-four hours after restoration, the extent of necrosis was estimated quantitatively via morphometric measurements of the relative surfaces of necrotic tissue in photomicrographs of gallocyanin-stained serial sections. After periods of ischemia longer than 40 min, the percentage of necrotic tissue increased linearly with the period of clamping. After 40 min of total ischemia the changes in hepatocytes are for the greater part reversible, whereas after 90 min the majority of the cells have passed the "point of no return" and will no more be able to maintain their integrity.

Animals↗