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Biomedical subjects

K Ostergaard

Publications and source records attributed to K Ostergaard.

At least 19 recordsLinked to original sources
PubMed1992

Tyrosine hydroxylase and acetylcholinesterase in the domestic pig mesencephalon: an immunocytochemical and histochemical study.

The mesencephalon of the young domestic pig was studied by tyrosine hydroxylase (TH) immunocytochemistry and acetylcholinesterase (AChE) histochemistry with focus on the substantia nigra (SN), the ventral tegmental area (VTA), and related areas. The purpose was to obtain information on the organization of the mesencephalic, TH immunoreactive (TH-i), and dopaminergic areas of the pig, in order to provide the necessary background for the possible use of the pig as an alternative large animal experimental model for research on Parkinson's disease, including the use of encapsulated pig dopaminergic neurons for intracerebral xenotransplantation. Significant findings in the pig, compared to observations in other species, included the presence of prominent bundles of TH-i dendrites passing in a dorsoventral direction from pars compacta into pars reticulata at middle and caudal levels of the SN, and the presence of a distinct TH-i substantia nigra pars lateralis (SNL). Caudally in the pig mesencephalon, the retrorubral field (RRF) was found to be very extensive. The view of the RRF, SN, and VTA as parts of the same integrated system was indicated by the crisscrossing of TH-i dendrites at the transitions between these areas. Estimation of the number of TH-i neurons in the SN and the VTA showed that these nuclei were of equal size in the pig. Further, it was found that TH-i nerve cells were present in the midline between the VTA in the interfascicular and rostral linear groups. TH-i nerve cells were also present in the otherwise serotoninergic dorsal raphe nuclei, just as other TH-i cells formed a perirubral cell group. AChE-positive neurons were present in both SN and VTA, and appeared to have the same size and morphology as the TH-i neurons in these areas. Within both nuclei, there were local differences in the AChE staining density, but perhaps more significantly were some marked differences in the structure of the AChE-positive neuropil of the two areas. We anticipate that the present description of the cellular organization of the TH-i dopaminergic areas in the domestic pig ventral mesencephalon will be useful for the development of a nonprimate, large animal, experimental model of Parkinson's disease.

Acetylcholinesterase↗
PubMed1992

Observer homogeneity in the histologic diagnosis of Helicobacter pylori. Latent class analysis, kappa coefficient, and repeat frequency.

Four pathologists independently examined 82 antral mucosal biopsy specimens for the presence of Helicobacter pylori and indicated whether their assessments were certain. The pathologists made a positive diagnosis in from 56% to 84% of the specimens (significant heterogeneity, p < 0.01). The frequency of uncertain diagnoses was from 4% to 20% (p < 0.01). Uncertain statements occurred more frequently among negative than among positive diagnoses. For the six pairs of observers the kappa coefficients were between 0.39 and 0.82. By a latent class analysis measures of diagnostic accuracy were calculated comparing the observers' assessments with an estimated consensus diagnosis. The predictive values of a positive diagnosis ranged from 0.70 to 1.00. By calculation of repeat frequencies--that is, the probability that an observer's statement was confirmed by another observer--it became evident that uncertain statements were less frequently (61%) confirmed than were certain ones (85%). It is concluded that observer homogeneity is only moderate with regard to the histologic diagnosis of H. pylori, which should be considered both in daily clinical routine and in scientific studies. Disagreement between observers was associated with negative diagnoses, presumably because the pathologists felt more uncertain in these cases.

Adult↗
PubMed1991

[Experimental clinical transplantation in patients with Parkinson disease. Experimental background and clinical picture].

In this review the experimental background for treatment of patients with Parkinson's disease by intracerebral transplantation is presented. Intracerebral transplantation has been performed either with the patients own adrenal medulla or with human fetal dopaminergic neurons obtained from abortions. Intracerebral transplantation of adrenal chromaffin cells to rodents has shown poor cell survival and minor, transient effects on experimentally induced parkinson-like symptoms. Intracerebral autotransplants of medullary adrenal tissue to patients with Parkinson's disease have shown corresponding, minor improvements in the parkinson status. Animal experiments with grafting of developing fetal dopaminergic neurons have been more rewarding and resulted in reversal of parkinson-like symptoms. Experimental transplantations with human fetal dopaminergic neurons to patients with Parkinson's disease have not entirely lived up to these expectations. At a recent meeting, arranged to set up a European network for research and information, it was agreed that more animal experiments, in particular including non-human primates are needed. Regarding the clinical trials with transplantation of human fetal dopaminergic tissue coordination of neurological test procedures performed pre- and posttransplantation was strongly recommended.

Adrenal Medulla↗
PubMed1991

Tyrosine hydroxylase immunoreactive neurons in organotypic slice cultures of the rat striatum and neocortex.

Organotypic slice cultures of striatum and neocortex were prepared from newborn to seven day old rats and cultured for three to 60 days. When processed for tyrosine hydroxylase (TH) immunocytochemistry medium-sized, aspiny TH immunoreactive (TH-i) neurons with a similar morphology were revealed in the striatum and the neocortex. The neurons had a very similar morphology in both tissues and were present both when the two tissues were grown separately as single cultures and when grown together either en bloc as part of the same tissue slices or as co-cultures. In order to examine whether innervation by dopaminergic fibers would affect the expression of TH-i neurons in the striatal slice cultures, co-cultures of ventral mesencephalon (VM) and striatum were prepared, but the ingrowth of TH-i fibers from the VM did not alter the expression of TH immunoreactivity by a subpopulation of striatal neurons.

Animals↗
PubMed1990

Rat ventral mesencephalon grown as organotypic slice cultures and co-cultured with striatum, hippocampus, and cerebellum.

Tissue slices of rat ventral mesencephalon (VM), striatum, hippocampus and cerebellum were prepared from late fetal (E21) to 7 day old (P7) rats and cultured for 3 to 60 days by the roller tube technique before they were stained immunocytochemically for tyrosine hydroxylase (TH), a marker of dopaminergic (DA) neurons and fibres. The TH immunoreactive (TH-i), DA neurons retained their morphological in vivo characteristics in the VM slice cultures consisting of the substantia nigra (SN) and the ventral tegmental area (VTA). The general morphology of the described neuronal cell types did not appear to change when the VM slices were co-cultured with striatal tissue, a major normal target of the DA neurons, but an extensive innervation of the striatum by TH-i nerve fibres was observed. In co-cultures of VM and hippocampus, a minor target organ of DA fibres, growth of TH-i nerve fibres was observed mainly into the opposing edge of the hippocampal slice. In co-cultures of VM and cerebellum, which is normally devoid of DA fibres, no significant growth of TH-i nerve fibres into the cerebellar slices was observed. Besides suggesting a target orientated growth of ventral mesencephalic DA fibres, the results point to the further use of VM slice cultures in the study of the developmental, plastic and regenerative properties of DA neurons.

Aging↗
PubMed1990

Methylmalonic acid concentrations in serum of normal subjects: biological variability and effect of oral L-isoleucine loads before and after intramuscular administration of cobalamin.

The clinical value of measuring concentrations of methylmalonic acid in serum (S-MMA) as an aid in the diagnosis of cobalamin deficiency has recently aroused interest. In 58 healthy subjects, ages 40-68 years, we found a 0.95 reference interval of 0.05-0.37 mumol/L (mean 0.21, SD 0.094). In 33 of the subjects, who were studied further, day-to-day variation (SD) was 0.031 mumol/L. Intake of food had no effect. Weekly and three-monthly intra-individual variations were both 0.038 mumol/L. In all seven subjects with S-MMA greater than 0.30 mumol/L, the concentrations declined significantly after intramuscular administration of cobalamin. No significant difference was found between mean serum cobalamin concentrations in these seven and in the remaining subjects. We have also established the normal response of S-MMA to standardized oral loading of L-isoleucine: 100 mmol caused a significant average S-MMA increase of 0.072 mumol/L before cobalamin administration vs 0.013 mumol/L after cobalamin, without significant relation to initial S-MMA values. Our results provide a necessary background for interpretation of S-MMA measurements in clinical studies.

Administration, Oral↗
PubMed1978

Renal cadmium concentration in relation to smoking habits and blood pressure.

The cadmium concentration of renal tissue from 120 patients, who had died at the age of 45-65 years, has been determined by atomic absorption spectrophotometry. The concentration did not differ significantly either between urban and rural dwellers or between male and female subjects. The concentration of cadmium in kidneys from cigarette smokers was about twice as high as in kidneys from non-smokers. Renal cadmium concentration was higher in normotensives than in hypertensives. When smoking habits were taken into account, renal cadmium concentration was found to be 82% higher in normotensives than in hypertensives. The possible roles of water hardness and selenium intake are discussed.

Aged↗
PubMed1978

Heart-autopsy findings in cases of sudden death. The distribution of infarctions, coronary stenosis and thrombi.

The pathological heart changes observed have been recorded at necropsy of 55 male and 31 female patients who died during transport to the hospital or in the casualty ward. The extension of acute myocardial infarction (AMI) was determined by a staining method using nitro-BT, and the infarctions were classified as transmural, combined or subendocardial. A total of 45 AMI's were found, and this is a lower frequency than normally found in sudden unexpected deaths when only death certificates are studied. The most frequent infarction type was the subendocardial infarction, which was present in 60% of the AMI-cases. Coronary thrombi were seen in only 24% of the AMI-cases, most frequently together with transmural infarctions.

Adult↗
PubMed1977

Cadmium and hypertension.

The cadmium concentration of renal tissue from 82 patients who had died at the age of 45-65 years has been determined by atomic absorption spectrophotometry; 43 were normotensive and 39 hypertensive. Renal cadmium concentration was higher in normotensives than in hypertensives. When smoking habits were taken into account, renal cadmium concentration was found to be 82% higher in normotensives than in hypertensives. Other workers have found the opposite relationship. It is proposed that this discrepancy might reflect either that variations due to age were not taken into account in previous investigations or that a difference exists between soft-water areas and hard-water areas such as the one studied.

Age Factors↗
PubMed1977

The concentration of cadmium in renal tissue from smokers and non-smokers.

The concentration of cadmium is determined by atomic absorption spectrophotometry of renal tissue excised at autopsy. Tissue from 19 non-smokers and 42 smokers of either sex in the age group 45-65 years has been analysed. The concentration of cadmium in kidneys from 16 subjects who had been smoking pipes, cigars or cheroots did not differ significantly from the concentration in non-smokers and cigarette smokers. On the other hand, in both normotensive and hypertensive individuals, the concentration of cadmium in kidneys from cigarette smokers was twice as high as in kidneys from non-smokers.

Aged↗