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M Grim

Publications and source records attributed to M Grim.

At least 19 recordsLinked to original sources
PubMed2003

[The Merkel cell: morphology, developmental origin, function].

Merkel nerve endings are mechanoreceptors in the vertebrate skin. They were named after the person who first described them--F.S. Merkel (1875). They consist of large, pale cells with lobulated nuclei forming synapse-like contacts with enlarged terminal endings of myelinated nerve fibres. Inside the cell are intermediate filaments formed of simple cytokeratins and osmophilic granules containing variety of neuropeptides. In mammals, they can be found in the basal layer of the skin and in those parts of the mucosa, which is derived from ectoderm. In contrast, in birds these cells are located in the dermis. The largest accumulation of Merkel nerve endings was found in whiskers of most mammals apart from man. There has been a controversy concerning the origin of Merkel cells. Results from chick/quail chimeras and most recently also from double transgenic mice have shown that Merkel cells are derived from the neural crest. Merkel cell play a role in the mechano-transduction process. In response to mechanical stimuli calcium ions enter Merkel cell and trigger the release of neurotransmitter probably glutamate. Thus, Merkel cell appears to be essential for characteristic slowly adapting response of these receptors during maintained mechanical stimuli. Cells in the skin of a similar appearance as Merkel cells are probably part of the diffuse neuroendocrine system and they do not function as mechanoreceptors. These cells, rather than those in mechanoreceptors, are most likely the origin of the highly malignant skin cancer called Merkel cell carcinoma.

Animals↗
PubMed2003

[Restoration of elbow joint flexion by transfer of the pectoralis major muscle in patients with arthrogryposis multiplex congenita. Part II. Results of electromyographic and histologic examinations].

PURPOSE OF THE STUDY: In the framework of a prospective study on transposition of the m. pectoralis major according to Clark in patients with type I arthrogryposis multiplex congenita, electromyography was carried out in order to determine pre-operative states of the elbow joint flexors and m. pectoralis major and then the post-operative electric activity of a transposed muscle and to correlate changes with clinical findings. Histological examination was performed to reveal changes in muscle morphology and to complete a comprehensive assessment of muscle transposition. MATERIAL AND METHODS: Electromyography was carried out on nine upper limbs of five pediatric patients aged 4.3 to 8.9 years. Using a needle electrode, activities of the elbow flexors (m. biceps and m. brachialis), m. pectoralis major, m. triceps brachii and m. deltoideus were examined. In the post-operative period, activity was repeatedly measured in both the transposed and non-transposed parts of the m. pectoralis major. In one patient, histological examination of muscle tissue was performed at 26 months after transposition; light microscopy of paraffin-mounted sections stained with hematoxylin-eosin was used. RESULTS: Out of seven arms examined by electromyography before muscle transfer, six showed complete and one incomplete atrophy of the m. biceps brachii and m. brachialis. The m. pectoralis major had a five- to four-degree electric activity, which provided enough strength for transposition. Post-operative examination revealed changes leading to re-innervation of the transposed muscle, which corresponded to a partial denervation of the muscle followed by repair of innervation. None of the muscles was markedly atrophic due to denervation. In muscles with a higher electric activity, clinical outcomes were better, although electric activity always slightly exceeded clinical activity. In terms of electric activity, the transposed muscle was stabilized a year after surgery. Non-transposed parts of the muscle were not damaged by the surgical procedure, as shown by electromyography. Histological examination showed the muscle at a state of partial atrophy but with signs of ongoing regeneration of muscle fibers. DISCUSSION: No data on examination of the electric activity of the m. pectoralis major following its transposition in patients with arthrogryposis multiplex congenita have been reported in the literature. Electromyography in this study proved useful for providing information on the electric activity of a muscle before transposition and on contractility of the muscle after surgery; it also allowed us to distinguish between a mechanical failure of transfer and muscle atrophy due to neurogenic or vascular causes. All transposed muscles that were examined revealed changes indicating a minimum denervation followed by re-innervation. This finding was confirmed by the results of histological examination. CONCLUSIONS: Electromyography showed that the electric activity of a transposed muscle corresponded to the clinical presentation of this muscle and thus became an indispensable part of both pre- and post-operative examination. Both electromyographic and histological examination confirmed the applicability of the treatment described here.

Arthrogryposis↗
PubMed2001

Lectin histochemistry of microvascular endothelium in chick and quail musculature.

The lectin binding pattern of muscular microvessels in chick, quail and chick/quail chimeras was analysed. Paraffin wax sections of muscles from embryonic and adult animals were used. The biotin-labelled lectins were detected by avidin-alkaline phosphatase complex. The following lectins bound to muscular microvessels including arterioles, capillaries and venules of both species: SNA-I (Sambucus nigra agglutinin), MAA (Maackia amurensis agglutinin), AIA (Artocarpus integrifolia agglutinin), VAA-I, VAA-II and VAA-III (Viscum album agglutinin I-III), WGA (wheat germ agglutinin), LEA (Lycopersicon esculentum agglutinin). Endomysium and basement membranes of muscle fibres were also stained to a variable extent and intensity. Only SNA-I stained almost exclusively the endothelium of blood vessels. WFA (Wisteria floribunda agglutinin) bound to the quail endothelium only. MPA (Maclura pomifera agglutinin) marked vessels in adult muscles of chick and quail, but embryonic vessels were stained in quail only. Our results show that lectin histochemistry is a useful tool for visualisation of microvasculature in avian species. In particular, WFA and MPA can be used to determine the origin of endothelia in chick/quail chimeras.

Animals↗
PubMed2000

Oxidative stress and AP-1 activity in tamoxifen-resistant breast tumors in vivo.

BACKGROUND: Most breast cancers, even those that are initially responsive to tamoxifen, ultimately become resistant. The molecular basis for this resistance, which in some patients is thought to involve stimulation of tumor growth by tamoxifen, is unclear. Tamoxifen induces cellular oxidative stress, and because changes in cell redox state can activate signaling pathways leading to the activation of activating protein-1 (AP-1), we investigated whether tamoxifen-resistant growth in vivo is associated with oxidative stress and/or activation of AP-1 in a xenograft model system where resistance is caused by tamoxifen-stimulated growth. METHODS: Control estrogen-treated, tamoxifen-sensitive, and tamoxifen-resistant MCF-7 xenograft tumors were assessed for oxidative stress by measuring levels of antioxidant enzyme (e.g., superoxide dismutase [SOD], glutathione S-transferase [GST], and hexose monophosphate shunt [HMS]) activity, glutathione, and lipid peroxidation. AP-1 protein levels, phosphorylated c-jun levels, and phosphorylated Jun NH(2)-terminal kinase (JNK) levels were examined by western blot analyses, and AP-1 DNA-binding and transcriptional activities were assessed by electrophoretic mobility shift assays and a reporter gene system. All statistical tests are two-sided. RESULTS: Compared with control estrogen-treated tumors, tamoxifen resistant tumors had statistically significantly increased SOD (more than threefold; P=.004) and GST (twofold; P=.004) activity and statistically significantly reduced glutathione levels (greater than twofold; P<.001) and HMS activity (10-fold; P<.001). Lipid peroxides were not significantly different between control and tamoxifen-resistant tumors. We observed no differences in AP-1 protein components or DNA-binding activity. However, AP-1-dependent transcription (P=.04) and phosphorylated c-Jun and JNK levels (P<.001) were statistically significantly increased in the tamoxifen-resistant tumors. CONCLUSION: Our results suggest that the conversion of breast tumors to a tamoxifen-resistant phenotype is associated with oxidative stress and the subsequent antioxidant response and with increased phosphorylated JNK and c-Jun levels and AP-1 activity, which together could contribute to tumor growth.

Animals↗
PubMed2000

Developmental origin of avian Merkel cells.

We have investigated the developmental origin and ultrastructure of avian Merkel cells by electron microscopy and chick/quail transplantation experiments. On embryonic day 3, chick leg primordia were homotopically grafted onto Japanese quail host embryo. Fourteen days later, quail cells that had migrated into grafted chick legs were identified according to the masses of heterochromatin associated with the nucleolus that are characteristic for quail. Both in chick and quail, Merkel cells are usually located in the dermis just below the epidermis. They are placed between nerve terminals either individually or in small groups wrapped in sheaths that are formed by glial cell processes. Occasionally, some Merkel cells appear in nerve fascicles and within Herbst corpuscles. Merkel cells, as well as glial cells, in grafted chicken legs were of quail origin. This finding provides evidence against the epidermal origin of avian Merkel cells and indicates that Merkel cells are derived from neural crest cells that colonise, together with glial cells and melanocytes, the developing limb primordium.

Animals↗
PubMed2000

Causes and treatment of residual urine volume after orthotopic bladder replacement in women.

OBJECTIVES: Intact innervation of the female urethra is conditional for normal urination. In the past, urethrectomy was performed as part of cystectomy. After intense anatomical studies of the female pelvis, urethral-function-sparing cystectomy was developed. METHODS: Our clinical group consists of 41 female patients who were operated from 1993 to 1998 for bladder cancer, utilizing cystectomy with orthotopic bladder replacement. RESULTS: In 28 patients, complete daytime continence was restored and in 13 patients, daytime continence was socially satisfactory (1-2 pads were used due to mild stress incontinence). The drawback of orthotopic replacements in females is the frequent development of serious residual volume, which was seen in one third of the 41 patients. The functional results of orthotopic neobladders and therapy of residual urine volume were documented using urodynamic studies. CONCLUSIONS: Postvoiding residual volume may be caused by isolated dysfunction of the urethra and can be treated with clean intermittent self-catheterization or with alpha-blockers, which improve evacuation of the neobladder.

Adult↗
PubMed1999

[Reconstruction of the lower urinary tract in women after cystectomy].

BACKGROUND: The first extirpation of the urinary bladder on account of malignant papilomatosis was carried out by Karel Pawlik in 1889 as the first one in the world. At present cystectomy is indicated usually because of an infiltrating carcinoma of the urinary bladder. The objective of the present paper is, based on anatomical investigations, elaboration of a surgical technique of creating a orthotopic neovesica following cystectomy sparing a functional female urethra. METHODS AND RESULTS: In 1993-1998 32 women were operated within the age bracket of 32-72 years with a confirmed infiltration carcinoma of the urinary bladder. The authors describe in detail their own surgical technique. Day continence was achieved in 20 patients. Twelve patients suffer from stress incontinence. Eight patients have a post-micturition residue of 250-300 ml calling for a combination of medicamentous treatment and autocatheterization. The capacity of the neovesicle is the cause of nycturia: 21 patients must micturate once or twice during the night. Urodynamic studies did not reveal significant differences between patients with chronic post-miction residues and without residues. Also the mean functional length of the urethra was in both groups similar (27 mm in patients with a residue and 26.2 mm in patients without a residue). CONCLUSIONS: The elaborated surgical technique of cystectomy and creation of a neovesica makes a good quality of the patients' life possible.

Adult↗
PubMed1999

Development of mechanoreceptor numbers in embryonic chick-quail chimeras.

Our experiments addressed the problem of the regulation of the number of mechanoreceptors by sensory axons and/or their peripheral target tissues. According to a previous study (Zelená et al. 1997) white leghorn chickens have more muscle spindles in the plantaris muscle (45.4+/-7.8; mean+/-SD) than the Japanese quail (35.3+/-4.8) and significantly more Herbst corpuscles in the crural region (380.0+/-85.0) than the quail (124.9+/-32.8). Embryonic chick-quail chimeras were therefore used as a model with distinct recombinations of the nerve supply and peripheral tissue for studying the developmental control of these mechanoreceptors. The chick host leg bud was replaced with a quail leg bud of equal age and vice versa on embryonic day 3, prior to the onset of innervation of the periphery. Shortly before hatching the chimeras were sacrificed and muscle spindles and Herbst corpuscles counted. Recombinations of chicken nerves with quail limb buds have shown that the richer nerve supply by chick Ia axons induced a significant increase in the number of muscle spindles in the plantaris muscles (55.5+/-13.4) of the grafted quail limb. In some instances, a similar increase in spindle numbers was also found in control legs grafted onto hosts of the same species. In the reverse type of chimera where chick embryo legs were grafted onto quail hosts, spindles developed in lower numbers (27.3+/-3.2). In that case the lower number of Ia axons in quail nerves induced a lower number of spindles in the chicken muscle. The numbers of Herbst corpuscles were, however, low in both types of chimera. Quail legs grafted onto host chick embryos contained 126.8+/-26.4 corpuscles, presumably due to a restrictive influence of the smaller crural area in the quail. Chick legs grafted onto quail hosts had only 99.6+/-34.1 crural corpuscles; the target area in chick embryo legs failed to attract more quail axons and/or to induce axonal sprouting. The developmental regulation of the number of the two types of mechanoreceptors examined in our study thus differ. While sensory axons appear to play the dominant role in the development of muscle spindles, their role seems to be restricted by hitherto unknown peripheral factors during the development of Herbst corpuscles.

Animals↗
PubMed1999

An alternative preparation of the acellular muscle graft for reconstruction of the injured nerve--morphological and morphometric analysis.

The application of cutaneous nerve grafts is accompanied by some disadvantages, including insufficient graft material for the reconstruction of a large mixed nerve. Recently, evacuated muscle autografts have been suggested as possible alternatives to cutaneous nerve grafts. In the present paper we have demonstrated a possible preparation of the evacuated muscle graft using an infiltration of Marcaine. The reinnervation of the distal stump of the rat median nerve was evaluated by morphological and morphometric analysis after application of the muscle acellular grafts prepared by three methods: an ordinary freeze-thawed muscle graft, a Marcaine evacuated muscle graft and a Marcaine treated graft with subsequent freezing and thawing. A comparison of the numbers and diameters of the myelinated axons in the distal nerve stumps revealed very similar conditions for axon regrowth and maturation in Marcaine evacuated and freeze-thawed muscle grafts. The best results with myelinated axon numbers and spectrum of their calibres were obtained when the Marcaine treated graft was repeatedly frozen and thawed. The pre-treatment of the muscle graft by Marcaine prevents it from shrinking and fragmenting, the main disadvantage during freeze-thawing of fresh muscle. The present results demonstrate that infiltration of striated muscles with a myotoxic compound, e.g. Marcaine, with subsequent freezing-thawing is the method of choice for the preparation of an acellular muscle graft used in peripheral nerve reconnection in the experimental model.

Animals↗
PubMed1999

[Anatomic illustration and its authors at the Medical School in Prague].

This article is a longer version of the introductory address opening the exhibition of anatomical illustration in the Academic Club of First Medical Faculty of Charles University in May 1999. The history of anatomical illustration, its significance and its two main forms, scientific drawing and didactical illustration, are shortly introduced. The development of this form of art at the Medical Faculty in Prague is shown and is demonstrated by examples of illustrations. Two old authors of illustrations are mentioned: an unknown author of illustrations of the first illustrated textbook of anatomy in Prague that was written by Ch. S. a Zeidlern, and F. Bĕlopotocký who illustrated the Atlas of Anatomy by W. Stanĕk written in Czech in 1840. In more detail are discussed the following artists and anatomical illustrators of 20th century connected with the Institute of Anatomy of Charles University: J. Rejsek, E. Illing, S. Machácek, M. Med, V. Seichert, I. Helekal a J. Kacvinský.

Anatomy, Artistic↗
PubMed1997

Crural Herbst corpuscles in chicken and quail: numbers and structure.

Herbst corpuscles were studied in the crural region of perinatal and adult chicken and quail in order to find out their number and dimensions and to learn more about their structure, especially in relation to size. Crural corpuscles are arrayed in an encapsulated string between tibia and fibula. They are closely packed together; a small number of corpuscles is found apart from the string, often attached to the periost. The strings of corpuscles are approximately 40 mm long in adult chicken and 20 mm long in the quail. The crural region of the chicken contains 382.8 +/- 90.9 (mean +/- SD) corpuscles, the numbers ranging from 301 to 582; in the quail, the mean number is 119.2 +/- 27.9, with a range from 83 to 167 corpuscles. In the chicken, one axon supplies an average of 1.60 corpuscles; in the quail, the relation of axons to corpuscles is approximately 0.92. In both species, final numbers of crural corpuscles are already attained before hatching and no difference is found in the mean number and range of corpuscles between perinatal and adult birds. In both chicken and quail, individual strings contain corpuscles of various sizes, from large to very small. The chicken corpuscles are generally twice as large in diameter and often longer than those of the quail. The corpuscles are composed of an axon terminal that projects two rows of axonal spines into the clefts of the inner core and ends with an ultraterminal bulb; the terminal is surrounded with a bilaterally symmetrical inner core, amorphous inner space containing collagen fibrils of various thickness, and a capsule. Large chicken corpuscles contain inner cores composed of up to 100 lamellae, while quail inner cores have half that number at the most. The capsules are usually composed of 8 to 10 lamellar layers in both species, but they are thicker in the chicken than in the quail. The possible functional significance of individual structural components of Herbst corpuscles is discussed.

Aging↗
PubMed1995

Blood vessel formation in the avian limb bud involves angioblastic and angiotrophic growth.

The vasculature of the avian limb bud takes its origin from the intersomitic vessels as can be shown by ink perfusion of the embryo. While the primitive vessels form a central network in the early limb bud, an area of about 100 microns in width from the ectoderm inward remains free from lumenized vessels. However, this subectodermal avascular zone contains isolated angioblasts, which can be demonstrated by confocal laser scanning microscopy in connection with QH-1-staining. QH-1-positive cells from the avascular zone are capable of giving rise to endothelial cells when grafted ectopically into a "permissive" environment such as the dorso-lateral paraxial mesoderm. Several grafting sites are compared regarding their permissiveness for capillary formation. In order to investigate the origin of the QH-1-positive angioblasts we carried out injections of DiI-Ac-LDL, which is specifically taken up by endothelial cells and macrophages, and found the lumenized vessels and a few isolated cells in the peripheral limb mesoderm stained. In double-labelling studies combining DiI-Ac-LDL and QH-1, it can be shown that there exists a pool of isolated angioblasts that are only QH-1-positive, but have not incorporated DiI-Ac-LDL. In contrast to the lumenized vessels in the core of the limb bud, we found that angioblasts in the avascular zone do not proliferate, as shown by proliferation studies applying the BrdU-method to semithin sections in connection with QH-1-labelled parallel sections. We conclude that the vascularization of the avian limb bud is achieved by a combination of angiotrophic growth (sprouting of vessels) and angioblastic growth (recruitment of angioblasts from the limb mesoderm.

Animals↗
PubMed1994

Early skeletal muscle development proceeds normally in parthenogenetic mouse embryos.

In mouse chimeras with parthenogenetic cell contribution, the skeletal musculature appears to be largely devoid of parthenogenetically derived cells. To analyze the appearance and early distribution of myotomal cells in parthenotes, we determined the expression of the muscle-specific transcription factors myogenin, MYF-5, and MYF-6 by in situ hybridization in somites of Day 10 and 11 embryos. Here, we report that these myogenic regulatory proteins are expressed in parthenogenetic animals together with desmin, one of the early muscle-specific structural proteins. We also show that parthenogenetic cells contribute equally to dermatome, sclerotome, and myotome in Day 10 and 11 chimeras. These results suggest that early myotomal cells expressing the myogenic control proteins develop and allocate normally in parthenogenetic embryos and in parthenogenetic<==>normal chimeras. The underrepresentation in older chimeras may therefore be due to selective elimination. These data also argue against imprinting of the myogenic factor genes myogenin, Myf-5, and Myf-6.

Animals↗
PubMed1994

Emergence of myogenic and endothelial cell lineages in avian embryos.

The roles of cell cycles and of cell-cell interactions in the emergence of myogenic and endothelial cell lineages were studied in avian embryos using the quail-chicken marker system. Quail embryos were treated with drugs preventing either DNA replication or the movement of cells. Portions of drug-treated or untreated quail blastoderms were grafted into chicken wing buds. After an incubation for an additional 4 to 10 days, the embryos were analyzed for the presence of quail muscle or quail endothelial cells by the Feulgen reaction and by immunostaining. Both cell lineages differ in the time of their commitment as well as in the conditions necessary for their emergence. Muscle cells did not differentiate from unincubated blastoderms nor did they develop from drug-treated blastoderms. These results corroborate that the commitment of myogenic cells occurs during gastrulation and indicate that this commitment requires both DNA replication and cellular movements allowing cell-cell and/or cell-matrix interactions. Endothelial cells, on the contrary, developed both from drug-treated and from unincubated blastoderms, indicating that their commitment occurs before and independent of gastrulation and does not require DNA replication during gastrulation.

Adenosine↗
PubMed1994

Principles of ontogenesis of leg and foot in man.

Human leg and foot anlagen of different developmental stages were studied by means of light and scanning electron microscopy. The findings were compared with principles of human arm and hand development and results obtained experimentally from chicken limbs. The limbs studied have in common the shaping, cell differentiation, and spatial arrangement of different cells as basic processes of development. On the other hand, upper and lower limbs are very different in human and avian embryos with regard to their position, form, and function. We found that the different positions in relation to the dorsal and ventral surfaces and maintenance of the apical ectodermal ridge (AER) are important factors leading to the different orientations and forms of limbs. The unequal length of the fingers and toes might also be explained in this way. Differences in the position of the most distal muscles in the hand and foot could be a consequence of the cranio-caudal sequence of development. The factors controlling the developmental differences between arm and leg are discussed.

Animals↗
PubMed1993

Sensory nerve endings in the beak skin of Japanese quail.

This study is concerned with the distribution and ultrastructure of sensory nerve endings in the beak skin of adult Japanese quail (Coturnix coturnix japonica). The following nerve endings were found: free nerve endings, clusters of dermal Merkel nerve endings, Herbst corpuscles and Ruffini corpuscles. The latter were found only in the dermis of the tip of the upper beak. The remaining endings were present in the skin of all areas of upper and lower beak. Free nerve endings were supplied by either thin myelinated axons or unmyelinated C-fibers and were localized in the dermis close to the basal layer of the epidermis. Merkel cells formed clusters (up to 50) localized below and between the epidermal cones of the beak skin. Disc-shaped thickenings of nerve endings were squeezed between individual Merkel cells. Small Herbst corpuscles were found in the dermis close to the epidermal cones of the beak skin. Large Herbst corpuscles occurred in deep layers of the dermis. The Ruffini corpuscles were cylindrical in shape (80 microns x 400 microns) and arranged in groups of up to ten corpuscles. Each corpuscle was surrounded by an incomplete fibrous capsule.

Animals↗