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Biomedical subjects

H Kalimo

Publications and source records attributed to H Kalimo.

At least 91 records · Page 5Linked to original sources
PubMed1989

The N-myc proto-oncogene and IGF-II growth factor mRNAs are expressed by distinct cells in human fetal kidney and brain.

We studied the expression of the N-myc proto-oncogene and the insulin-like growth factor-II (IGF-II) gene in human fetuses of 16-19 gestational wk. Both genes have specific roles in the growth and differentiation of embryonic tissues, such as the kidney and neural tissue. Since continued expression of N-myc and IGF-II mRNAs is also a characteristic feature of Wilms' tumor, a childhood neoplasm of probable fetal kidney origin, we were particularly interested in the possibility that their expression might be linked or coordinately regulated in the developing kidney. Expression of N-myc mRNA was observed in the brain and in the kidney by Northern hybridization analysis. In in situ hybridization of the kidney, N-myc autoradiographic grains were primarily located over epithelially differentiating mesenchyme while most of the mesenchymal stromal cells showed only a background signal with the N-myc probe. N-myc mRNA was detectable throughout the developing brain with a slight accentuation in the intermediate zone cells in between the subependymal and cortical layers. Thus, even postmitotic neuroepithelial cells of the fetal cerebrum expressed N-myc mRNA. In Northern hybridization, IGF-II mRNA signal was abundant in the kidney but much weaker, though definite, in the brain. The regional distribution of IGF-II mRNA in the kidney was largely complementary to that of N-myc. IGF-II autoradiographic grains were located predominantly over the stromal and blastemal cells with a relative lack of hybridization over the epithelial structures. In the brain, IGF-II mRNA was about two- to threefold more abundant in the subependymal and intermediate layers than in the cortical plate and ependymal zone, respectively. The fetal expression patterns of the N-myc and IGF-II mRNAs are reflected by the types of tumors known to express the corresponding genes during postnatal life such as Wilms' tumor. However, the apparent coexpression of the IGF-II and N-myc genes in immature kidneys occurs largely in distinct cell types.

Autoradiography↗
PubMed1989

Connective tissue changes of the multifidus muscle in patients with lumbar disc herniation. An immunohistologic study of collagen types I and III and fibronectin.

The connective tissue components, Types I and III collagen fibronectin, were immunohistologically analyzed using their specific antibodies for localization and semiquantitative estimation in 24 patients (11 women and 13 men, all under 55 years of age) operated on for herniated lumbar intervertebral disc. Nine cadavers without known back problems (2 women, 7 men) served as controls. In controls, Type I collagen was present in the endo- and perimysial structures of the muscle, more conspiciously in the former. Type III collagen, together with fibronectin, were more abundant in the perimysium than in the endomysium. Thickening of these structures was not evident in the controls. In most patients Types I and III collagen and fibronectin distribution was similar to that of the controls. However, fibrotic changes of both and endo- and perimysial structures involved all Types I and III collagen and fibronectin in ten cases. In two patients an increase in Type I collagen staining intensity in the endomysium was recorded and thickening of the endomysial structures was observed in six patients. There were correlations with the severity of the connective tissue structural changes to atrophy of the muscle and furthermore to disability of the patient in the 1-year postoperative check-up. These findings suggest that if marked fibrosis of the muscle occurs, it can be a factor impairing recovery from the disease during the long-term postoperative course.

Adult↗
PubMed1989

Two cases of Dandy-Walker syndrome and chronic polyneuropathy.

The paper describes a so far unreported combination of Dandy-Walker syndrome and chronic hereditary polyneuropathy in 2 boys. One of the boys has a de- and remyelinating motor and sensory polyneuropathy, with either an autosomal recessive mode of inheritence or a sporadic occurrence. The other has an autosomal dominant form of mild polyneuropathy with tomaculum formations in myelinated fibers, corresponding to hereditary neuropathy with liability to pressure palsies.

Adult↗
PubMed1989

Lumbar muscles: structure and function.

We review new data derived from careful dissection studies on the macroscopic anatomy, innervation and function of the lumbar muscles, as well as information on the fibres in these muscles. The new findings correct previous misconceptions of the functional anatomy of the lumbar muscles. The innervation and function of the erector spinae and multifidus muscles are so different that they cannot be classified as a single unit. The new interpretation of the innervation of multifidus muscle is of importance, for example, for the neurophysiological examination of the lumbar muscles. The relative number of the slow and fast type of muscle fibres in lumbar muscles varies considerably, and selective atrophy of the fast fibres seems to ensue from inactivity, not only in patients with back pain but also in sedentary controls. The atrophy may be corrected by adequate exercise. Both the fibre type composition and degree of atrophy may well influence a person's susceptibility to low back pain arising from the muscles.

Adult↗
PubMed1989

Dynamic changes of excitatory amino acid receptors in the rat hippocampus following transient cerebral ischemia.

The changes in excitatory amino acid receptor ligand binding induced by transient cerebral ischemia were studied in the rat hippocampal subfields. Ten minutes of ischemia was induced by common carotid artery occlusion combined with hypotension, and the animals were allowed variable periods of recovery ranging from 1 day to 4 weeks. The binding of 3H-AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) to quisqualate receptors, 3H-kainic acid (KA) to kainate receptors, and 3H-glutamate to N-methyl-D-aspartate (NMDA) receptors as determined by quantitative autoradiography. One week following ischemia the CA1 region of the hippocampus displayed a severe (90%) dendrosomatic lesion with preservation of presynaptic terminals. This was associated with a 60% decrease in AMPA binding and a 25% decrease in glutamate binding to NMDA receptors. At 4 weeks postischemia, both AMPA and NMDA sites were greatly reduced. Although the dentate gyrus granule cells are resistant to an ischemic insult of this magnitude, this region showed marked changes in receptor binding. One week following ischemia, the AMPA and NMDA binding decreased by approximately 40 and 20%, respectively. Following 2 weeks of recovery, the NMDA binding was not significantly different from control level, while the AMPA binding remained depressed up to 4 weeks postischemia. The high density of KA binding sites in the inner molecular layer of the dentate gyrus was unaffected by the ischemic insult, despite an extensive degeneration of cells in the hilus of dentate gyrus which projects glutamatergic afferents to this area.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Gene deletions in X-linked muscular dystrophy.

Of the approximately 170 families with X-linked muscular dystrophy of the Duchenne (DMD) and Becker (BMD) type in Finland, we have studied 90 unrelated patients for intragenic deletions by using the cDNA probes described by Koenig et al. Forty-five patients (50%) had molecular deletions of one or several of the 65 exon-containing HindIII fragments. In six deletion cases junction fragments of altered size were seen. Thirty-eight (84%) of the 45 deletions were detected using only two (1-2a and 8) of the six cDNA subclones. Using a wheelchair age of 12 years to distinguish between DMD and BMD, we found that the proportions of patients with deletions were similar. Deletions were equally common in familial and sporadic disease. BMD was more commonly caused by deletions in the 5' end of the gene than was DMD. In at least three instances deletions of similar type resulted in diseases of similar severity. Of 14 patients with mental retardation seven had deletions; six of these comprised exons contained in probe 8. We conclude that cDNA hybridization studies provide a powerful diagnostic tool in DMD and BMD and that they promise to produce better insights into molecular-clinical correlations.

Chromosome Deletion↗
PubMed1988

A syndrome of multiple congenital contractures: neuropathological analysis on five fetal cases.

We performed a neuropathological study on 5 fetuses with an autosomal recessive, lethal syndrome of congenital contractures diagnosed by fetal hydrops on ultrasonography. The fetuses showed a typical pattern of malpositioning of hips and knees with occasional pterygia of the neck and elbows. The muscles were hypoplastic and the spinal cords showed severe thinning, most markedly affecting the ventral half. A total loss of axons in the ventral and lateral funiculi, subtotal loss of anterior horn motor neurons with accompanying astrocytosis and astrogliosis, and similar but less severe changes at the brain stem level suggested a degenerative rather than a dysmorphogenetic mechanism. Sensory nuclei and pathways were distinctly less severely affected, if at all. The findings further delineate this condition as a genetically and pathoanatomically distinct autosomal recessive syndrome.

Abnormalities, Multiple↗
PubMed1988

X-linked myopathy with excessive autophagy: a new hereditary muscle disease.

We report on 3 brothers with a myopathy that also affected their maternal grandfather and great-uncle. Characteristic features are onset in early childhood, very slow progression, normal life expectancy, weakness of proximal limb muscles, especially in the legs, elevation of serum creatine kinase, and no cardiac or intellectual involvement. In biopsy material muscle fibers are almost never necrotic but show excessive autophagic activity and exocytosis of the phagocytosed material. We suggest that this family has an undescribed type of congenital myopathy, for which we propose the name X-linked myopathy with excessive autophagy.

Adult↗
PubMed1988

A transient hypertensive opening of the blood-brain barrier can lead to brain damage. Extravasation of serum proteins and cellular changes in rats subjected to aortic compression.

A transient increase in blood pressure was induced in 15 male Sprague Dawley rats by clamping the upper abdominal aorta for 8-10 min. Three rats served as controls. The brains were fixed by perfusion 2 h or 7 days later. Evan's blue-albumin (EBA) was used for macroscopic evaluation of the blood-brain barrier (BBB) integrity. Extravasated plasma albumin, fibrinogen and fibronectin were demonstrated by immunohistochemistry on paraffin sections. Glial fibrillary acidic protein (GFAP) was visualized in the same way. Parallel sections were analyzed for possible parenchymal changes associated with the BBB breakdown. Multiple focal areas of BBB opening were seen in the brains of the three rats killed 2 h after the hypertensive episode. The plasma proteins were present in the vascular wall, extracellular space and within certain neurons. Shrunken acid fuchsin positive neurons were seen in some areas of extravasation. After 7 days, in 5 out of 12 rats a few local lesions with EBA leakage and positive immunostaining for plasma proteins were seen. Structurally these lesions were characterized by shrinkage, fuchsinophilia and disintegration of neurons and proliferation of astrocytes. Thus, a transient opening of the BBB by acute hypertension may lead to permanent tissue damage.

Acute Disease↗
PubMed1988

Cyst formation and glial response in the brain lesions of stroke-prone spontaneously hypertensive rats.

The brain lesions in spontaneously hypertensive stroke-prone rats (SHRSP) are characterised by multifocal microvascular damage, breakdown of the blood-brain barrier, massive extravasation of plasma constituents and severe brain oedema, with consequent spongy and cystic tissue destruction in the cerebral cortex and basal ganglia as well as loosening of the white matter. In this paper we analyse in greater detail the pathogenetic mechanisms by which the spongy and cystic lesions are formed and the response of astrocytic cells. For this purpose, tracer (Evans blue)-stained brain lesions were examined in 8-month-old SHRSP immunohistochemically and electron microscopically. Sponginess of the neuropil in small lesions and at the periphery of larger lesions was due to swollen neuronal and astrocytic cell processes, i.e. at this stage the oedema was mainly intracellular. Cystic lesions were formed in the grey matter both by expansion of the extracellular space (ECS) containing protein-rich oedema fluid, and by rupture and subsequent loss of massively swollen cellular elements. In the white matter small slit-formed cysts along the fibre tracts were also formed by the expansion of ECS. In apparently recent lesions astrocytes displayed cyto-plasmic oedema but otherwise were still fairly normal. In more chronic lesions increased numbers of enlarged astrocytes with prominent staining for glial fibrillary acidic protein were present. Their distribution corresponded well to the spread of oedema, i.e. they were prominent around the leaky vessels in the grey matter, in the subpial zone and in the white matter. In the reparative phase the grey matter cysts became lined by astrocytic processes, a new glia limitans. Profuse sheets of glial processes in the neuropil around the cysts reestablished the compactness of the brain parenchyma.

Animals↗
PubMed1988

Observations on exsudation of fibronectin, fibrinogen and albumin in the brain after carotid infusion of hyperosmolar solutions. An immunohistochemical study in the rat indicating longlasting changes in the brain microenvironment and multifocal nerve cell injuries.

An immunohistochemical study was carried out on rat brain to determine if a transient opening of the blood-brain barrier (BBB), leading to extravasation of serum albumin, is also associated with exudation and cellular uptake of fibronectin and fibrinogen. Both of them might exert important biological effects provided that they pass the BBB and come into contact with cells of the brain parenchyma. Hyperosmolar solutions of urea or mannitol were infused in the carotid artery for 30 s to open the BBB and the animals were killed at various time intervals thereafter. Formaldehyde-fixed, paraffin-embedded material was used for immunohistochemical demonstration of extravasated proteins by an avidin-biotin peroxidase technique. Multifocal, often confluent areas of widely different sizes with signs of albumin extravasation were observed both in the grey and the white matter of the cerebral hemispheres exposed to the hyperosmolar solutions. Much less pronounced changes were observed in rats given an intracarotid saline infusion alone. Immunoreactive material indicating extravasation of fibronectin and fibrinogen was present in the infused cerebral hemispheres but albumin immunoreactivity was much more widespread. Reaction product was observed in vascular walls, presumably in extracellular spaces and in nerve cells. Immunoreactivity in the perikaryon of neurons formed different patterns in various cells. A granular type most probably represents accumulation of the proteins in lysosomal organelles after pinocytotic uptake into the neuron. The second so-called diffuse variety is presumably the result of a severe nerve cell injury with an uncontrolled leakage of proteins into the cytoplasm. Our results indicate that vascular walls, extracellular spaces, glial cells and neurons will be exposed to extravasated fibronectin and fibrinogen as well as to albumin and that antigenic sites in such compounds remain for a long period after the BBB opening. In addition, there are indications that carotid infusions of hyperosmolar solutions may cause nerve cell injuries in regions with BBB opening. These findings have obvious clinical and experimental significance.

Animals↗
PubMed1988

Nerve cell injury in the brain of stroke-prone spontaneously hypertensive rats.

The brain lesions in stroke-prone spontaneously hypertensive rats (SHRSP) are characterized by multifocal microvascular and spongy-cystic parenchymal alterations particularly in the gray matter. An essential feature of the lesions is the presence of edema with massive extravasation of plasma constituents as evidenced by specific gravity measurements, Evans blue technique and immunohistochemistry. The nerve cell injury occurring in the brain lesions in SHRSP is further characterized by light and electron microscopy in the present study. Two types of neuronal changes were seen within the blood-brain barrier (BBB) leakage sites. A small number of neurons with dark condensed nucleus and cytoplasm were found most often at the periphery of recent lesions. The majority of injured neurons were pale and showed intracellular edema confined to the dendrites and perikarya sparing axons and synapses. Their nuclei were well preserved with finely dispersed chromatin. The swollen and watery cell processes of neurons and astrocytes gave a spongy appearance to the neuropil. The intracellular edema seemed to result in cytolysis. The results suggest that primary anoxia-ischemia is not the major pathogenetic mechanism behind the nerve cell injury in severely hypertensive SHRSP, rather it is the massive BBB leakage and consequent brain edema that causes cytolytic destruction of neurons. Secondary focal ischemia as a consequence of occlusion in microvessels may, however, contribute to the nerve cell destruction.

Animals↗
PubMed1988

Morphological lesions in the brain preceding the development of postischemic seizures.

This study explores how hyperglycemia and enhanced tissue lactic acidosis influence the density and distribution of ischemic brain damage. Ischemia of 10-min duration was produced in glucose-infused rats by bilateral carotid clamping combined with hypotension, and the brains were perfusion-fixed with formaldehyde following recirculation of 3, 6, 12 and 18 h. After about 24 h the hyperglycemic animals developed seizures, and at that time two groups were added, one fixed prior to, and one after the onset of seizures. Similar experiments were made on normoglycemic animals with recirculation times of 1.5 to 96 h. After fixation the brains were embedded in paraffin, subserially sectioned and stained with celestine blue/acid fuchsin. In both normo- and hyperglycemic animals, neurons in the dentate hilus of the hippocampal formation and in the thalamic lateral reticular nucleus showed early and dense neuronal necrosis. In neocortex, hippocampal CA1 sector and caudoputamen, hyperglycemia shortened the delay before damage occurred and markedly enhanced the damage. Specific for the hyperglycemic animals was damage of the substantia nigra, pars reticulata (SNPR), manifest already at the earliest recovery periods studied; this finding is discussed in relationship to the role SNPR is assumed to play in preventing spread of seizure discharge.

Animals↗
PubMed1988

Reactions of vessel walls and brain parenchyma to the accumulation of Gaucher cells in the Norrbottnian type (type III) of Gaucher disease.

Splenectomy in children with the Norrbottnian type of Gaucher disease is followed by increased blood levels of glucosylceramide and impaired neurological and mental status. High blood levels are associated with an increased accumulation of glucosylceramide in perivascular Gaucher cells in the brain compared to non-splenectomised cases. Surrounding the Gaucher cell infiltrates there is loss of neurons and slight demyelination in the brain parenchyma. The brains of four cases with the Norrbottnian type of Gaucher disease were examined by immunohistochemical stains in an attempt to further characterize the perivascular Gaucher cells and to examine the reactions of the vessel walls and brain parenchyma to the accumulation of Gaucher cells. The perivascular storage cells showed granular staining with antibodies to muramidase and alpha 1-anti-chymotrypsin confirming that they are blood-derived macrophages belonging to the monocyte-macrophage system. The Gaucher cells contained material positive for antisera to plasma proteins strongly suggesting that large molecules (including glucosylceramide) can escape from the blood and be taken up by the macrophages in Gaucher disease. The storage cells were surrounded by a reticulin network stained by antisera to collagen type III, type IV and laminin. The infiltrates were bounded from the brain parenchyma by a membrane strongly positive with antiserum for the basal lamina protein collagen type IV and laminin. The formation of a basal lamina around the Gaucher cell cuffs probably constitutes a protective phenomenon governing the brain parenchyma against the foreign cells. A focal loss of neurons but only minor loss of axons could be demonstrated with the antiserum to neurofilament.(ABSTRACT TRUNCATED AT 250 WORDS)

Astrocytes↗
PubMed1988

Structural changes in the rat brain after carotid infusions of hyperosmolar solutions. An electron microscopic study.

Infusion of hypertonic solutions into the carotid artery is one method by which the blood-brain barrier (BBB) can be opened transiently in experimental animals. This technique has also been tried in clinical situations in which an enhanced uptake of intravenously injected chemotherapeutic drugs into the brain is desired. We have previously found that infusion of hypertonic mannitol or urea into the carotid artery of the rat, leading to a BBB opening, is associated with light microscopic signs of cellular damage in the brain parenchyma. An electron microscopic study has now been made to obtain more detailed information about the events taking place in the rat brain 1 to 72 h after an intracarotid infusion of hyperosmolar solution of mannitol. Toluidine blue-stained semithin epon sections were also available for high-resolution light microscopy of brain samples from urea-infused animals. Intravenously injected Evan's blue dye was used to confirm that BBB opening had occurred as a consequence of the carotid infusions. The infused hemispheres had numerous structural changes. The dominating light microscopic alteration was the presence of multifocal lesions in the gray or the white matter with closely packed microvacuoles causing status spongiosus. Ultrastructurally the microvacuoles corresponded to very pronounced watery swelling of astrocytic processes and to a minor degree to expansion of dendrites and axons. There was also a light or moderate perivascular astrocytic swelling. In the "spongy" lesions as well as occasionally in non-vacuolated parts of the cerebral cortex, there were collapsed electron-dense neurons with pronounced mitochondrial alterations such as severe swelling associated with rupture of christae.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Cerebral microangiopathy in stroke-prone spontaneously hypertensive rats. An immunohistochemical and ultrastructural study.

The morphology of cerebral microvessels was studied immunohistochemically and ultrastructurally in 6- to 9-month-old normotensive Wistar-Kyoto rats (WKY), spontaneously hypertensive rats (SHR), and stroke-prone SHR (SHRSP) with a systolic blood pressure of 138 +/- 15 mm Hg, 189 +/- 9 mm Hg, and 258 +/- 30 mm Hg respectively. Regions with major opening of the blood-brain barrier (BBB) were revealed by an i.v. injection of Evans Blue. Multifocal BBB opening with massive leakage of plasma constituents rich in fibrinogen-fibrin-related antigen occurred in SHRSP with a blood pressure above 210-220 mm Hg. BBB-leakage sites were found in the cerebral cortex and the basal ganglia, most frequently in the arterial border zones. The perivascular tissue spaces were dilated within the BBB-leakage sites, in particular around arterioles. Damaged endothelial and smooth muscle cells were replaced by fibrin-like material, multiple layers of basement membranes and bundles of collagen fibrils surrounded by proliferated fibroblasts. The degenerative-infiltrative-proliferative disease process transformed short segments of single arterioles into severely thickened, tortuous and stenotic vessels. Fibrinoid degeneration, formation of microaneurysms and fibrin-rich vascular occlusions were observed. In contrast, only minor or no vascular alterations were seen in regions with preserved BBB in SHRSP and SHR. A severely increased intraluminal pressure load appears to be of major pathogenetic importance for breakdown of the BBB and initiation of the vascular disease process in SHRSP. However, since only short segments of a limited number of widely separated vessels are severely affected, and the number of affected vessels increase towards arterial end and border zones, additional predisposing and aggravating factors may play significant roles in the development of fibrinoid vascular lesions in arterial hypertension.

Animals↗