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Biomedical subjects

J C Hansen

Publications and source records attributed to J C Hansen.

162 records · Page 9Linked to original sources
PubMed1976

Polyvinylpyrrolidone-storage disease. Light microscopical, ultrastructural and chemical verification.

The light and electron microscopical findings in the polyvinylpyrrolidine-storage disease are reported on the basis of biopsies of skin, striated muscle, bone marrow and liver from one patient and a subcutaneous nodule from another patient. Both patients suffer from diabetes insipidus and have been treated for several years with Insipidin retard, which contains polyvinylpyrrolidone (PVP) as the retarding agent. Deposits of PVP have been demonstrated in all the tissues examined and can easily be recognized by certain staining qualities. The combination of haematoxylin-eosin, elastin (Weigert), alkaline Congo red and Sirius red for amyloid and PTAH is specially to be recommended. The ultrastructural findings consist of intracellular vacuoles containing a granular material and probably representing lysosomes. The final identification of the nature of the deposits has been made by spectrophotometric analysis. The suspicion of a case of PVP-storage disease should result in a skin biopsy which usually is sufficient for the diagnosis.

Bone Marrow↗
PubMedDate not supplied

Lymphocyte glutathione peroxidase activity during exacerbations in multiple sclerosis.

Glutathione peroxidase, one of the major antioxidants in the human brain, has been found to have decreased activity in patients suffering from multiple sclerosis (MS). This study compares the activity of lymphocyte glutathione peroxidase (L-GSH-px) in MS patients suffering from acute relapses with clinically stable MS patients and with control patients referred with nondemyelinating neurological diseases. All three groups showed an increase of mean enzymatic activity (MEA) during the observation period. The highest MEA in this study was observed in the MS groups. However, there were no significant differences in the L-GSH-px activity in the three groups. These results are not in accordance with previous investigations, and the need for further research in this field is emphasized.

Adult↗
PubMedDate not supplied

Event-related potentials during selective attention to speech sounds.

Event-related potentials (ERPs) were recorded from subjects while they selectively attended to sequences of stop-consonant syllables or sequences of tone pips of different frequencies. The ERP difference waveforms that distinguished attended from unattended speech sounds were highly similar in morphology and scalp distribution to the difference waveforms elicited by the tone pips. These results suggest that the attention mechanisms brought into play when selecting complex phonetic stimuli for further analysis are similar to those engaged when selecting between tones of different frequencies, in contrast with previous theoretical interpretations. Latency differences observed between the attention-related ERPs to simple and complex stimuli were attributed to differences in the duration of processing that makes these stimulus features available to attention mechanisms.

Adolescent↗
PubMedDate not supplied

Prenatal exposure to methyl mercury among Greenlandic polar Inuits.

During the period 1982 to 1988, 37 paired samples of blood from Inuit women and their newborn children were collected in North Greenland. The samples were analyzed for whole blood content of total mercury (tot-Hg) and for content of methyl mercury (Me-Hg). In maternal blood, 80% of the tot-Hg was found to be methylated in contrast to 98% in cord blood. Concentrations of Me-Hg in maternal and cord blood were significantly correlated, and the mean ratio between fetal and maternal blood Me-Hg was 1.9. Concentrations of Me-Hg in cord blood were closely related to the marine food intake of the mothers. Eighty-four percent of the mothers had blood concentrations of Me-Hg above 0.11 mumol/l (23 micrograms/l), which corresponds to the provisional limit of tolerable intake set by the World Health Organization. This indicates that the majority of the pregnant woman have an unacceptable high intake of methyl mercury.

Adult↗
PubMedDate not supplied

Organic mercury: an environmental threat to the health of dietary-exposed societies?

As a natural element, mercury is ubiquitous in the environment. The largest amount of mercury, amounting to approximately 100,000 tons per year, originates from the degassing of the earth's crust. To this amount, such anthropogenic activities as combustion of fossil fuels and releases from industrial activities add approximately 20,000 tons of mercury every year. The emitted mercury, both natural and anthropogenic, is in an inorganic form, predominantly as the metallic vapor (Hgzero). In aquatic environments, however, inorganic mercury is microbiologically transformed into the lipophilic organic compound, methylmercury. The transformation from the hydrophilic to the lipophilic state makes mercury more prone to biomagnification in aquatic food chains. Consequently, populations with a traditionally high dietary intake of food originating from either fresh-water or marine environments have the highest exposure to methylmercury. Because of their traditional pursuit of marine mammals, the Inuits belong to the highest dietary exposure group /1/. This situation is particularly true for the Polar Eskimos in North West Greenland. This population has the most traditional lifestyle among the Inuits and hunts predatory species of whales, such as beluga and narwhal, a combination that results in a high level of exposure to methylmercury. Polar Eskimos in North West Greenland, living in areas with no 'accidental' mercury pollution, but with a high dietary access to methylmercury thus exemplify a population group with a current potential environmental health problem.

Carcinogens, Environmental↗
PubMedDate not supplied

Effects of T cells on platelet-derived growth factor-like protein secretion from endothelial cells.

The cause of accelerated graft arteriosclerosis after heart transplantation is unknown. To examine whether the interactions of T cells and endothelial cells (ECs) could contribute to the cause of this phenomenon, T cells were co-incubated with human umbilical artery endothelial cells (HUAEC) and human vein endothelial cells (HUVEC) and the resulting conditioned medium supernatant was assayed for the presence of platelet-derived growth factor (PDGF)-like protein. PDGF-like protein secretion was significantly greater from HUAECs co-incubated with T cells at T-cell/HUAEC ratios of 30:1 (6.9 +/- 1.1 fmol/10(6) ECs) and 10:1 (6.0 +/- 1.1 fmol/10(6) ECs) than the combined background secretion from HUAECs and T cells incubated separately (3.6 +/- 0.8 fmol/10(6) ECs) (p less than 0.05). PDGF-like protein secretion above background levels from HUAECs was significantly greater, however, than from HUVECs co-incubated with T cells at T-cell/HUVEC ratios of 30:1 (1.0 +/- 0.4 fmol/10(6) ECs) and 10:1 (0.75 +/- 0.36 fmol/10(6) ECs) (p less than 0.05). In four experiments, preincubation of HUAECs with gamma-interferon induced HLA-DR antigen expression but actually caused a decrease in T-cell-induced PDGF-like protein secretion above background levels (3.0 +/- 0.6 fmol/10(6) ECs) when compared to nonstimulated HUAECs (4.0 +/- 0.4 fmol/10(6) ECs; p less than 0.05). PDGF-like protein secretion was minimal at 1 hour and increased over time to a maximum at 24 hours. The conclusion is that T cells are capable of inducing secretion of a very potent mitogen, PDGF-like protein, from endothelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

3T3 Cells↗
PubMedDate not supplied

Cadmium and selenium levels in kidneys from Danish horses.

The content of cadmium and selenium in horse kidneys from Jutland , Denmark, in relation to age, local geographical variation and possible relationship between the two elements has been investigated. During the winter of 1982-1983 kidneys from 50 horses were sampled and analysed for cadmium and selenium. The cadmium content of the horse kidneys was recorded in connection with the age of the horses. The cadmium level increases until the animal has reached approximately 7 years of age. At this age the cadmium concentration levels off. A significant regional difference was shown. The cadmium content is higher in horse kidneys from South and Central Jutland than in kidneys from North Jutland (Fig. 2). This geographic pattern is consistent with the one for atmospheric deposition of cadmium and cadmium content in Danish cattle kidneys from Jutland . The cadmium level in kidneys from Danish horses is considerably lower than the level in Norwegian and Swedish horse kidneys. Differences in water hardness and atmospheric deposition may explain some of this difference within Scandinavian countries. The selenium concentration shows no relationship with neither age, cadmium content nor place of rearing. So, the study did not reveal any relationship between the cadmium and selenium concentrations in horse kidneys. The high level of cadmium found in Danish horse kidneys emphasizes the importance of a prohibition against the use of the kidneys in animal and human nutrition, as proposed by others.

Age Factors↗