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Biomedical subjects

J Maehlen

Publications and source records attributed to J Maehlen.

At least 19 recordsLinked to original sources
PubMed2002

Early psychomotor slowing predicts the development of HIV dementia and autopsy-verified HIV encephalitis.

OBJECTIVES- To ask if slowed motor speed predicts later human immunodeficiency virus (HIV) dementia and HIV encephalitis. METHODS- In 100 deceased acquired immunodeficiency syndrome (AIDS) patients prior results from repeated testing of the movement reaction time test were correlated with later clinical signs of HIV dementia and with neuropathological signs of HIV encephalitis. Autopsy was performed in 72 patients. RESULTS- Movement reaction time 1-2 years prior to death, or at the time of clinical AIDS diagnosis predicted both development of HIV dementia (P<0.05) and HIV encephalitis at autopsy (P<0.01). CONCLUSION- Testing for early psychomotor slowing may be used to identify patients at risk of HIV dementia and HIV encephalitis.

AIDS Dementia Complex↗
PubMed2001

[Norwegian breast cancer mortality rates and validity of Swedish mammographic studies].

BACKGROUND: The claim that screening for breast cancer with mammography reduces breast cancer mortality is mainly based on the results from the Swedish two-county trial (WE study), where the effect was reported to be 30% for the age group 50-69 years. The two-county trial has recently been criticised for inadequate randomisation and for not following the study protocol. METHODS: We do some simple calculations to study whether the WE study is robust for an alternative statistical analysis. We use stage-specific breast cancer mortality in the Norwegian population as the baseline mortality rate in Sweden. Then we study the expected reduction in overall breast cancer mortality in the WE study while we vary the mortality rate in stage 1 and the stage distribution. RESULTS: We show that a 30% reduction in overall mortality rate is in conflict with observed decline in mortality in stage 1 and the expected stage migration. One either has to decrease mortality in stage 1, or increase the reduction of tumours with distant metastases, or both, to much higher levels than those reported in Sweden to get a 30% reduction in overall mortality of breast cancer. CONCLUSIONS: Our study adds further evidence to the proposal that the WE study is biased and not valid.

Aged↗
PubMed2001

[South American blastomycosis--a differential diagnosis to tuberculous meningitis].

BACKGROUND: South American blastomycosis is primarily a lung infection often complicated by multiorgan or intracranial disease. MATERIAL AND METHODS: We describe the clinical and pathological findings of fatal cerebral blastomycosis occurring in a woman that immigrated to Norway from Brazil 23 years earlier. RESULTS: The clinical symptoms together with the radiological findings of multiple cerebral lesions and thickening of the basal meninges were interpreted as cerebral tuberculosis. Examination of cerebral spinal fluid was inconclusive. A diagnosis of cerebral fungal infection was subsequently established by brain biopsy. INTERPRETATION: This case history stresses the importance of confirming a clinical diagnosis by brain biopsy and extended investigation of the cerebrospinal fluid when intracranial lesions may have an infectious origin.

Diagnosis, Differential↗
PubMed2001

Myointimal hyperplasia and sympathetic reinnervation following local cold injury and rapid rewarming in the rabbit central ear artery.

BACKGROUND: Functional and pathological improvements following rapid rewarming in 42 degrees C water was compared with alterations following slow thawing at room temperature (22 degrees C) after frostbite (-9 degrees C, 15 minutes) in vivo of the rabbit central ear artery. METHODS: Following two to ten weeks of in vivo regeneration, vascular segments were tested in vitro. Maximal and dose-dependent isometric contractions were induced by exogenous noradrenaline. Sympathetic nerves in the vascular wall were stained with glyoxylic acid. Vascular ring segments were stained with haematoxylin and eosin. RESULTS: Following slow thawing, the total uptake, the K+ evoked and the spontaneous release of [3H]noradrenaline in the sympathetic nervous system were strongly reduced two weeks after freezing, with a subsequent increase to control level within 3-4 weeks. After rapid rewarming the total uptake, the spontaneous release and the K+ evoked release of [3H]noradrenaline commenced earlier such that after ten weeks the level was twice as high as following slow rewarming. The glyoxylic acid induced catecholamine fluorescence in sympathetic nerves, revealed an earlier regeneration after rapid rewarming. Haematoxylin and eosin-stained segments revealed less intimal hyperplasia three to 20 weeks after rapid rewarming than after slow thawing. CONCLUSION: Rapid rewarming of in vivo frozen arteries in warm water (42 degrees C) did not prevent immediate vasoparalysis and degeneration of sympathetic nerves. However, nerve regeneration occurred earlier and with higher tissue nerve densities as compared to tissue that had been slowly rewarmed. Myointimal hyperplasia was less pronounced after rapid rewarming. Abnormal sympathetic nerve function and myointimal hyperplasia, as observed in this study, may contribute to a greater understanding of sequelae in the human body following frostbite.

Adrenergic Fibers↗
PubMed2001

Dementia in AIDS patients in Oslo; the role of HIV encephalitis and CMV encephalitis.

In a well-defined population of adult AIDS patients from Oslo, we studied the correlation between clinical dementia and autopsy results. The study included 91% of all adult AIDS patients from Oslo who died between 1983 and 1996. The autopsy rate was 73% (167/229). Twenty-three percent of patients had definite dementia and 24% possible dementia. In more than half of the patients with definite dementia multinucleated giant cells were present in the brain tissue, suggesting that the dementia was due to HIV encephalitis. Diffuse damage of white matter also showed a significant association with clinical dementia. When found alone it tended to occur in symptomatic patients with a short survival time from onset of dementia until death. This indicates that diffuse damage of white matter may be an early stage of HIV encephalitis. CMV encephalitis was found in 28 cases (17%). Of these, 20 were classified as definitely or possibly demented. In 14 of these 20 cases we detected no multinucleated giant cells, suggesting that CMV caused or contributed to the dementia. Multiple logistic regression supported an association between CMV and conditions clinically classified as HIV dementia. We conclude that HIV encephalitis is the major cause of dementia in AIDS patients, but that CMV encephalitis as a cause of dementia has been underestimated.

AIDS Dementia Complex↗
PubMed2001

Evidence for intraaxonal spread of Listeria monocytogenes from the periphery to the central nervous system.

Rhombencephalitis due to Listeria monocytogenes is characterized by progressive cranial nerve palsies and subacute inflammation in the brain stem. In this paper, we report observations made on mice infected with L. monocytogenes. Unilateral inoculation of bacteria into facial muscle, or peripheral parts of a cranial nerve, induced clinical and histological signs of mainly ipsilateral rhombencephalitis. Similarly, unilateral inoculation of bacteria into lower leg muscle or peripheral parts of sciatic nerve was followed by lumbar myelitis. In these animals, intraaxonal bacteria were seen in the sciatic nerve and its corresponding nerve roots ipsilateral to the bacterial application site. Development of myelitis was prevented by transsection of the sciatic nerve proximally to the hindleg inoculation site. Altogether, our results support the hypothesis that Listeria rhombencephalitis is caused by intraaxonal bacterial spread from peripheral sites to the central nervous system.

Animals↗
PubMed2000

[The olfactory sense].

BACKGROUND: In mammals, olfactory stimuli influence various aspects of life including feeding, social behaviour, and reproduction. METHODS: We review the progress in olfactory research in the last decade. RESULTS: In this era of gene-based techniques, a breakthrough in our knowledge on odorant and pheromone detection has occurred. Most importantly, a large gene family of odorant receptors expressed in the olfactory epithelium has been discovered. Subsets of receptor cells express one and only one receptor type and send their axons to a corresponding glomerulus in the olfactory bulb, giving rise to an odor-specific map in this structure. Two gene families of pheromone receptors expressed in the vomeronasal organ have also been discovered, and a role of pheromones in mammalian reproduction has been established. INTERPRETATION: Although the crucial steps in odorant binding and transduction to nerve signals have been revealed, the central processing of this sensory information is basically unknown. Moreover, whether pheromones serve a significant role in human behaviour is still an open question.

Animals↗
PubMed2000

Injectional anthrax in a heroin skin-popper.

Anthrax is rare in western Europe but may arise sporadically in people exposed to animal products from endemic areas. A heroin-injecting drug user presented with a severe soft-tissue infection at the injection site, septic shock, and meningitis. A gram-positive endospore-forming aerobic rod was isolated from the soft tissue and cerebrospinal fluid; confirmation of Bacillus anthracis was made by PCR. Since contaminated heroin was the probable source of infection, this case is of concern and warrants surveillance.

Anthrax↗
PubMed2000

[Will the revolutionary knowledge of apoptosis play an important role in medicine?].

Apoptosis is a phenomenon of fundamental importance in embryonal development and the homeostatic regulation of mature tissue. We review the present knowledge on apoptosis and the evidence that apoptosis may play a role in the pathogenesis of human disease. As examples we discuss its role in cancer, ischemic diseases, heart failure and neurodegenerative diseases.

Apoptosis↗
PubMed2000

Association between apolipoprotein E genotypes and cancer risk in patients with acquired immunodeficiency syndrome.

The apolipoprotein E (apoE) genotype was determined in 197 deceased acquired immunodeficiency syndrome (AIDS) patients treated at Ullevaal Hospital in Oslo, Norway. A full autopsy had been performed on all. Cancer had developed in 71 individuals, mainly lymphomas (46) and Kaposi's sarcomas (18). The apoE genotype distribution was consistent with Hardy-Weinberg equilibrium, and allele frequencies were in the typical Scandinavian range (6.9% apoE2; 75.6% apoE3; and 17.5% apoE4). Cancer cases had a significantly higher frequency of apoE4 alleles than noncancer cases (24.6% and 13.5%, respectively) and a lower frequency of apoE2 alleles (3.5% versus 8.7%). Background factors, such as survival from AIDS diagnosis, could not explain these differences. Our study thus indicates that apoE genotype affects the development of cancers among AIDS patients.

Acquired Immunodeficiency Syndrome↗
PubMed1999

[The amyloid and tau hypothesis in degenerative dementia].

Alzheimer's disease is the major cause of dementia. The neuropathological basis for the diagnosis is the presence of senile plaques and neurofibrillary degeneration in brain tissue. Senile plaques consist of a central core of fibrillar amyloid beta-protein and some other proteins, surrounded by swollen neurites. Three genes causing early-onset autosomal dominant Alzheimer have so far been described. Recently, polymorphisms in three other genes have been shown to influence the risk for late-onset Alzheimer's disease. All these genes seem to influence the metabolization of the beta-protein or the precursor for this protein. These findings support the "amyloid hypothesis" which states that toxic effects of beta-protein cause Alzheimer's disease. Frontotemporal dementias are the second most common types of degenerative dementias, and may account for more than 10% of the dementias. A substantial number of these cases are probably caused by a mutation in the gene for tau protein on chromosome 17.

Aged↗
PubMed1999

[Brain stem infection caused by Listeria monocytogenes].

Rhombencephalitis due to Listeria monocytogenes is a serious form of brainstem inflammation. It is difficult to diagnose on the basis of clinical and laboratory findings alone. We describe a fatal case of Listeria monocytogenes rhombencephalitis in a previously healthy female teenager. Clinical and pathogenetic aspects of this condition are discussed.

Adolescent↗
PubMed1999

[Listeria monocytogenes--the perfect parasite?].

The pathogen Listeria monocytogenes has an extraordinary intracellular life cycle, based on adaption to and exploitation of normal cellular mechanisms. Extracellular organisms induce their own phagocytosis, followed by destruction of the phagosomal membrane. Cytoplasmatic bacteria organize the intracellular protein actin into "comet tails", and thus gain motility. In contact with the plasma membrane, motile bacteria induce a pseudopodium, corresponding to an invagination of the plasma membrane of the neighbouring cell. Eventually, the pseudopodium is engulfed by the neighbouring cell, creating a double membrane vacuole. L. monocytogenes destroys the double membrane, and escapes into the cytoplasm. This article reviews the molecular biology of Listeria infection, and how research in this field has yielded increased insight into normal cellular processes. Finally, we propose that the neuroinvasive properties of L. monocytogenes is caused by actin-dependent transport within axons from the periphery to the central nervous system.

Actins↗
PubMed1999

Denervation enhances spontaneous inflammatory myopathy in SJL mice.

We studied the effect of denervation on the spontaneous inflammatory myopathy that occurs in SJL mice. Cryosections from innervated and denervated calf muscles were assessed for severity of inflammation, relative proportions of mononuclear cell subsets, and major histocompatibility complex (MHC) class I expression. A significant increase in mononuclear cell infiltrates occurred in the denervated muscle. Denervation also changed the composition of mononuclear cell infiltrates towards a higher percentage of CD8(+) T cells (19% versus 11%). MHC class I expression was enhanced in denervated muscle compared with innervated muscle. Our findings indicate that inflammation in muscle may be enhanced by denervation.

Animals↗
PubMed1999

Early and late functional and histopathological perturbations in the rabbit ear-artery following local cold injury.

BACKGROUND: These experiments aimed to study the in vivo short and long term neurovascular regeneration after frostbite. METHODS: The rabbit central ear-artery was used as the experimental model. The effects on the noradrenergic innervation of the artery were measured in isolated vascular ring segments the first day and 2, 3-4, and 8-10 or 10-20 weeks following freezing at -9 degrees C or -18 degrees C for 15 min with slow rewarming for 7 min at room temperature. RESULTS: Two days after freezing the sympathetic nerves were completely degenerated, as observed with glyoxylic acid-induced fluorescence. The vascular isometric tension responses to exogenous noradrenaline and endogenously released noradrenaline by electrical stimulation in vitro were abolished. A varying degree of necrosis of the vascular wall was observed. Two weeks after freezing at -18 degrees C in vitro responses to exogenous noradrenaline and electrical stimulation were still abolished, then gradually approaching control levels after 10-20 weeks of in vivo regeneration. Eight and 10 weeks after injury at -9 degrees C increased vascular tension responses to exogenous noradrenaline was found. In spite of a long regeneration period the total uptake and the spontaneous and K+ (75 mM) evoked releases of [3H]noradrenaline were persistently decreased after frostbite at -18 degrees C, but they were regenerated to control levels already 10-20 weeks after -9 degrees C. Regeneration of noradrenergic nerve function, expressed as [3H]noradrenaline uptake and release and responsiveness to electrical stimulation, expressed as vascular contraction, was slower than the regeneration of the vascular smooth muscle. Myointimal hyperplasia developed in response to -9 degrees C and -18 degrees C frostbite. The uptake and the K+ evoked release of [3H]noradrenaline were particularly sensitive parameters for autonomic nerve function. CONCLUSIONS: The present findings may demonstrate important neurovascular reactions to local frostbite and may explain human sequelae following frostbite.

Adrenergic Fibers↗