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PubMed1966

Structure and organization of the living mitotic spindle of Haemanthus endosperm.

New details of mitotic spindle structures in the endosperm of Haemanthus katherinae (Bak) have been demonstrated by differential interference microscopy. Spindle fibers are clearly seen in the living spindle extending from the kinetochores to the polar region. Individual spindle fibers consist of a bundle of smaller filaments which diverge slightly from the kinetochore and intermingle with filaments from other spindle fibers as they approach the polar region. The degree of intermingling increases during metaphase and anaphase. The chromosomes stop moving when the spindle fibers are still 5 to 10microns long; then the fibers disappear. These observations explain some aspects of spindle movements which were difficult to reconcile with earlier concepts of spindle organization.

Cell Division↗

PubMed1989

Ultrastructure of spindles and tufts in human dental enamel.

A transmission electron microscope (TEM) study was made of spindles and tufts as identified in the light microscope, from samples prepared by selected-area argon-ion-beam thinning. Spindles in human dental enamel were found to be continuous with dentinal tubules across the dentin-enamel junction (DEJ) and usually appeared at the DEJ as electron-lucent, empty channels nearly circular in cross-section. The spindles were found to cross prism boundaries, branched rarely, and some were occasionally found to be occluded or partially occluded with small needle-like crystals (approximately 5 nm width and approximately 70 nm length), granular material (approximately 1.5 nm diameter) and/or amorphous material. Near the DEJ, the majority of spindles had a diameter less than 2 microns, while in the prismatic enamel away from the DEJ, spindles with a diameter greater than 2 microns were generally found. Spindle varicosity was characterized by an enlargement of their diameter. Tufts started at the DEJ and were not associated with dentinal tubules. Two types of ultrastructure were observed in the TEM: (i) disrupted regions of enamel incorporating large voids (up to approximately 0.1 microns in diameter), or, more commonly, (ii) channels within the enamel occluded or partially occluded, with small needle-like crystals and granular and/or amorphous material similar to that found in the enamel spindles. It was concluded that spindles and tufts represent areas of hypomineralization with increased void volume and partial remineralization.

Child↗

PubMed1982

Sleep spindles recorded from deep cerebral structures in man.

The depth and scalp EEG findings in 73 patients with intractable epileptic seizure disorder and in 14 patients with intractable pain were reviewed; stress was laid on the area of earliest spindle activity. It was found that sleep spindles frequently occurred first in frontal depth leads and especially in the superior frontal region (supplementary motor region). In some cases, spindles in frontal depth leads occurred while the patient showed early drowsy activity or even waking activity (with posterior basic rhythm) in the scalp leads. In patients with thalamic implants, spindles tended to appear on the thalamus before appearance on the scalp. The general rule that sleep onset (NREM) is characterized by the appearance of spindles is valid for the scalp EEG only. Deep spindle activity occurs much earlier and probably requires a certain degree of synchronization before spindle activity is noticeable in scalp leads. The superior frontal region is likely to be the starting point of spindle activity.

Adult↗

PubMed1984

Cyclic variation of integrated spindle components during nocturnal sleep in mentally retarded children.

The cyclic variation of the integrated spindle component in 77 mentally retarded children (from 3 months to 12 years of age) was studied throughout nocturnal sleep. In 31 out of 77 subjects high integrated spindle rhythm power was noted in the sleep EEG. In 24 subjects, low integrated spindle rhythm power was found, and in the remaining 22 subjects no integrated spindle rhythm power was noted throughout nocturnal sleep. There was a significant increase in abnormal clinical EEGs in subjects with no spindle rhythm power as compared to those with high and low spindle rhythm powers. A significant decrease in DQ was found in the subjects with no spindle rhythm power as compared to those with high and low spindle rhythm powers.

Brain↗

PubMed1976

Effect of psychotropic drugs on caudate spindle in cats.

To ascertain whether neuroleptics act on the caudate nucleus itself, the effects of these compounds as well as other centrally acting drugs were examined in relation to caudate spindle and EEG arousal responses (sciatic nerve stimulation) in gallamine-immobilized cats. Haloperidol and chlorpromazine enhanced the caudate spindle at a dose which had no effect on the EEG arousal response. On the other hand, clozapine and a higher dose of chlorpromazine enhanced the caudate spindle, but depressed the arousal response. High frequency stimulation of the sciatic nerve suppressed the caudate spindle. Pentobarbital, biperiden and diazepam, while depressing the arousal response, caused an enhancement of the caudate spindle. Imipramine at a low dose had no effect on either response, whereas at a high dose this drug enhanced the caudate spindle with concomitant depression of the arousal response. From these results, it may be concluded that the enhancing action on the caudate spindle induced by haloperidol and a low dose of chlorpromazine is due to an increase in susceptibility of the caudate nucleus itself. In addition, it is suggested that depression of the activating system is involved in an appearance of the caudate spindle.

Animals↗

PubMed2000

Sleep spindle incidence dynamics: a pilot study based on a Markovian analysis.

Results are reported, based on 5 healthy subjects, concerning patterns in the dynamics of the sequential arrangement of spindles in human stage 2 sleep. Specifically, the conditional probability of incidence of successive spindle lengths and successive inter-spindle intervals is investigated. The results show that successive spindle lengths may be statistically independent. However, their distribution (histogram) may be similar for two different stage 2 periods, one in the first third and another in the second third of the night sleep record. In contrast to the finding about spindle lengths, results show that successive inter-spindle intervals may not be statistically independent. Furthermore, the overall dynamics of the sequential arrangement of inter-spindle intervals may be similar for the two sleep periods. These findings are discussed in the context of the "sleep maintenance" role of spindles.

Adult↗

PubMed2001

[Mycobacterial spindle cell pseudotumor of lymph nodes].

OBJECTIVE: To study the clinicopathological of mycobacterial spindle cell pseudotumor in lymph nodes. METHODS: Two cases of spindle cell pseudotumor in the lymph nodes of infants were examined using light microscopy. The sections were stained with HE, Ziehl-Neelsen and studied immunohistochemically. RESULTS: Both infants were 1 year of age and had a history of Bacilli Calmette Guerin (BCG) vaccination before discovery of their lymph node lesions. Clinically, the patients presented fever and enlarged lymph nodes. Histopathologically, the lesions showed proliferation of spindle cells arranged in bundles, storiform patterns with abundant capillaries and lymphocyte, plasma cell and neutrophil infiltration forming a spindle cell pseudotumor. Most of the spindle cells were phagocytic cells which contained large amounts of mycobactrium as observed by Ziehl-Neelsen staining. Immunohistochemical staining showed strongly positive result for Mac387 and lysosome, but negative for S-100 in spindle cells and histocytes. CONCLUSIONS: Mycobacterial spindle cell pseudotumor of lymph nodes may occur not only in immunodeficient patients (such as AIDS) but also in infants after BCG vaccination. The lesions may mimic spindle cell tumor in lymph nodes, therefore it is very important to recognize these lesions in order to treat the patient properly.

BCG Vaccine↗

PubMed2002

Grouping of spindle activity during slow oscillations in human non-rapid eye movement sleep.

Based on findings primarily in cats, the grouping of spindle activity and fast brain oscillations by slow oscillations during slow-wave sleep (SWS) has been proposed to represent an essential feature in the processing of memories during sleep. We examined whether a comparable grouping of spindle and fast activity coinciding with slow oscillations can be found in human SWS. For negative and positive half-waves of slow oscillations (dominant frequency, 0.7-0.8 Hz) identified during SWS in humans (n = 13), wave-triggered averages of root mean square (rms) activity in the theta (4-8 Hz), alpha (8-12 Hz), spindle (12-15 Hz), and beta (15-25 Hz) range were formed. Slow positive half-waves were linked to a pronounced and microV (23.4%; p < 0.001, with reference to baseline) at the midline central electrode (Cz). In contrast, spindle activity was suppressed during slow negative half-waves, on average by -0.65 +/- 0.06 microV at Cz (-22%; p < 0.001). An increase in spindle activity 400-500 msec after negative half-waves was more than twofold the increase during slow positive half-waves (p < 0.001). A similar although less pronounced dynamic was observed for beta activity, but not for alpha and theta frequencies. Discrete spindles identified during stages 2 and 3 of non-rapid eye movement (REM) sleep coincided with a discrete slow positive half-wave-like potential preceded by a pronounced negative half-wave (p < 0.01). These results provide the first evidence in humans of grouping of spindle and beta activity during slow oscillations. They support the concept that phases of cortical depolarization during slow oscillations, reflected by surface-positive (depth-negative) field potentials, drive the thalamocortical spindle activity. The drive is particularly strong during cortical depolarization, expressed as surface-positive field potentials.

Adolescent↗

PubMed1967

Cell motility by labile association of molecules. The nature of mitotic spindle fibers and their role in chromosome movement.

This article summarizes our current views on the dynamic structure of the mitotic spindle and its relation to mitotic chromosome movements. The following statements are based on measurements of birefringence of spindle fibers in living cells, normally developing or experimentally modified by various physical and chemical agents, including high and low temperatures, antimitotic drugs, heavy water, and ultraviolet microbeam irradiation. Data were also obtained concomitantly with electron microscopy employing a new fixative and through measurements of isolated spindle protein. Spindle fibers in living cells are labile dynamic structures whose constituent filaments (microtubules) undergo cyclic breakdown and reformation. The dynamic state is maintained by an equilibrium between a pool of protein molecules and their linearly aggregated polymers, which constitute the microtubules or filaments. In living cells under physiological conditions, the association of the molecules into polymers is very weak (absolute value of DeltaF(25 degrees C) < 1 kcal), and the equilibrium is readily shifted to dissociation by low temperature or by high hydrostatic pressure. The equilibrium is shifted toward formation of polymer by increase in temperature (with a large increase in entropy: DeltaS(25 degrees C) approximately 100 eu) or by the addition of heavy water. The spindle proteins tend to polymerize with orienting centers as their geometrical foci. The centrioles, kinetochores, and cell plate act as orienting centers successively during mitosis. Filaments are more concentrated adjacent to an orienting center and yield higher birefringence. Astral rays, continuous fibers, chromosomal fibers, and phragmoplast fibers are thus formed by successive reorganization of the same protein molecules. During late prophase and metaphase, polymerization takes place predominantly at the kinetochores; in metaphase and anaphase, depolymerization is prevalent near the spindle poles. When the concentration of spindle protein is high, fusiform bundles of polymer are precipitated out even in the absence of obvious orienting centers. The shift of equilibrium from free protein molecules to polymer increases the length and number of the spindle microtubules or filaments. Slow depolymerization of the polymers, which can be brought about by low concentrations of colchicine or by gradual cooling, allows the filaments to shorten and perform work. The dynamic equilibrium controlled by orienting centers and other factors provides a plasusible mechanism by which chromosomes and other organelles, as well as the cell surface, are deformed or moved by temporarily organized arrays of microtubules or filaments.

Birefringence↗

PubMed1984

Sucrose-induced spindle elongation in mitotic PtK-1 cells.

Brief treatment of mitotic metaphase and anaphase PtK-1 cells with tissue culture medium containing 0.5 M sucrose resulted in spindle elongation without chromosome motion. Spindle birefringence also changed from a uniform appearance to one of highly birefringent bundles. Electron microscopic analysis indicated these birefringent bundles were composed of tightly packed arrays of spindle microtubules. No kinetochores could be seen following a 10 min sucrose treatment. Upon removal of sucrose, metaphase spindles returned to pretreatment lengths and the normal birefringence pattern returned. Reduction in spindle length could be temporally coupled with the reappearance of kinetochores and the reassociation of microtubules with these structures. In contrast to treated and released metaphase cells, anaphase spindles did not return to pretreatment lengths. Replacement of sucrose with medium showed the resumption of chromosome-to-pole motion within 2 min of sucrose removal. Chromosome motion could be correlated with the reappearance of kinetochores and kinetochore microtubules. These data have led us to postulate the existence of two microtubule continuums in the spindle and to discuss their roles in spindle organization and chromosome motion.

Anaphase↗

PubMed1981

[Spindles and spike waves in the sleep EEG of epileptic patients under administration of phenobarbital (PB) and phenytoin (DPH) (author's transl)].

As part of a study on the influence of some antiepileptic drugs on the sleep of epileptic patients, we investigated the changes of sleep spindles and spike wave discharges. 8 Patients with generalized epilepsy whose polygraphic sleep records before drug treatment were known, received PB and DPH in consecutive monotherapy. Sleep was investigated with steady state therapeutic levels of both drugs. Spindle activity, as compared with the base-line night, was increased with PB and decreased with DPH (p less than 0.05). Three of the 8 patients had slow spindles (6--9/s), together with diminished sigma spindles (12--14/s). Obvious influences of the drugs on these slow spindles were not observed. A relationship between spindle activity and spike wave discharge was indicated by the fact that those 5 patients in whom spike wave activity was significantly diminished or abolished by PB treatment, had a more than 50% increase of spindles, whereas the 3 other had not. With DPH, however, there was no systematic relation between spindles and spike waves. It is therefore considered that the relationship between both phenomena is not very close or causal, and that the effect of DPH on spike wave discharge might be partly different from the effect of PB.

Electroencephalography↗

PubMedDate not supplied

[Spatio-temporal organization of ECoG spindles during sleep onset].

Spatio-temporal organization of spindle activity in the cerebral cortex during deepening of slow-wave sleep (SWS) was studied in experiments on cats and rabbits. Patterns of both "sleep" and recruiting reaction spindles were analyzed. In the process of sleep development spindle activity was transformed from local to a diffuse one, organized in a sort of packages. The rate of synchroneity in spindle packages depended on the sleep depth. At the deepest SWS stages a sharp desynchronization of spindles in the packages was observed and then--complete disappearance of spindle activity. Interaction of thalamic spindle pacemakers seems to play an important role in the mechanism of SWS development; changes in it result in reorganization of spindle activity on the cortical surface. A considerable part in this interaction is reserved to the processes of emergence and spread of delta-activity.

Animals↗

PubMed1995

Identification of interleukin-1 and platelet-derived growth factor-B as major mitogens for the spindle cells of Kaposi's sarcoma: a combined in vitro and in vivo analysis.

By means of a combined in vitro and in vivo analysis we provide evidence that IL-1 beta and PDGF-B, but not OSM (oncostatin M) or IL-6, are major mitogens for the spindle cells of Kaposi's sarcoma (KS) in vivo. PDGF-B and IL-1 beta stimulated proliferation of cultivated KS spindle cells in vitro. Analysis of gene expression in vivo revealed that both factors as well as the PDGF beta-receptor are present in KS lesions. By contrast, IL-6 had no effect and OSM inhibited proliferation of cultivated KS spindle cells. Again, the effect of these factors on cultivated KS spindle cells in vitro was reflected by the gene expression observed in KS lesions in vivo. Neither the expression of IL-6 receptor nor of OSM could be detected in KS lesions by in situ hybridization. Moreover, in situ hybridization revealed an identical pattern of gene expression in cultivated KS spindle cells and KS spindle cells in vivo with respect to the above-mentioned cytokines [PDGF-B, IL-1 beta, IL-1 alpha, IL-6, OSM] and their receptors [PDGF beta-receptor, gp130, IL-6 receptor, leukemia inhibitory factor (LIF) receptor]. This further supported the suitability of cultivated KS spindle cells as an in vitro model in order to determine which cytokines may activate proliferation of KS spindle cells in vivo.

Cell Division↗

PubMed1997

Mitosis in cells with unreplicated genomes (MUGs): spindle assembly and behavior of centromere fragments.

Chinese hamster ovary (CHO) cells, which are arrested at the G1/S-phase of the cell cycle with hydroxyurea, enter mitosis prematurely when treated with caffeine [Schlegel and Pardee, 1986; Science 233-1264-1266]. Such mitotic cells with unreplicated genomes (MUGs) can assemble a mitotic spindle and progress through M-phase even in the absence of intact, replicated chromosomes [Brinkley et al., 1988: Nature 336:251-254; Zinkowski et al., 1991: J. Cell Biol. 113:1091-1110; Christy et al., 1995: Protoplasma 186:193-200]. In order to better define the role of the spindle in chromosome movement, we compared the structure and assembly of mitotic spindles and analyzed the nature of kinetochore association and movement in control cells and MUGs. The mitotic spindles in MUGs display the same morphological features and dynamic properties of assembly-disassembly as seen in normal spindles. Although multiple centromere-kinetochore fragments (CKFs), derived from fragmented chromosomes, interact with and attach to spindle microtubules in both orthodox and unorthodox ways, they nevertheless become aligned on the metaphase plate. Prometaphase congression and alignment at metaphase is achieved in MUGs even though CKFs represent kinetochore fragments that originate from unreplicated chromosomes and, therefore, lack "sister kinetochore" orientation such as seen in chromosomes of control cells. Our study supports the notion that much of the "information" needed for prometaphase chromosome movement and alignment is endemic to the spindle.

Animals↗

PubMed1998

Skeletal fiber types and spindle distribution in limb and jaw muscles of the adult and neonatal opossum, Monodelphis domestica.

The South American opossum, Monodelphis domestica, is very immature at birth, and we wished to assess its potential for studies of jaw muscle development. Given the lack of prior information about any Monodelphis fiber types or spindles, our study aimed to identify for the first time fiber types in both adult and neonatal muscles and the location of spindles in the jaw muscles. Fiber types were identified in frozen sections of adult and 6-day-old jaw and limb muscles by using myosin ATPase and metabolic enzyme histochemistry and by immunostaining for myosin isoforms. The distribution of fiber types and muscle spindles throughout the jaw-closer muscles was identified by immunostaining of sections of methacarnoy-fixed, wax-embedded heads. Most muscles contained one slow (type I) and two fast fiber types (equivalent to types IIA and IIX), which were similar to those in eutherian muscle, and an additional (non-IIB) fast type. In jaw-closer muscles, the main extrafusal fiber type was IIM (characteristic of these muscles in some eutherians), and almost all spindles were concentrated in four restricted areas: one in masseter and three in temporalis. Six-day neonatal muscles were very immature, but future spindle-rich areas were revealed by immunostaining and corresponded in position to the adult areas. Extrafusal and spindle fiber types in Monodelphis share many similarities with eutherian mammalian muscle. This finding, along with the immaturity of myosin isoform expression observed 6 days postnatally, indicates that Monodelphis could provide a valuable model for studying early developmental events in the jaw-closer muscles and their spindles.

Animals↗

PubMed2000

Dissecting the role of molecular motors in the mitotic spindle.

Accurate segregation of genetic material during both mitosis and meiosis is essential for the viability of future cellular generations. Genetic material is packaged in the form of chromosomes during cell division, and chromosomes are segregated equally into two daughter cells by a dynamic, microtubule-based structure known as the spindle. Molecular motor proteins of the kinesin and dynein superfamilies are essential players in the functional microanatomy of cell division. They power various aspects of spindle assembly and function, including establishing spindle bipolarity, spindle pole organization, chromosome alignment and segregation, regulating microtubule dynamics, and cytokinesis. This review highlights the roles that various members of the kinesin and dynein motor superfamilies play during mitosis and meiosis. Understanding how microtubule motors function during cell division will unravel how the spindle precisely segregates chromosomes, and may offer insights into the molecular basis of disease states that arise from spindle malfunctions. For example, chromosome non-disjunction during meiosis causes such disorders as Klinefelter, Turner, and Down Syndromes. Chromosome non-disjunction during mitosis is an important contributing mechanism for tumor progression. In addition, since motor proteins are essential for spindle assembly and function, they provide obvious targets for intervention into the cell division cycle, and compounds that specifically block motor functions during mitosis may prove to be valuable chemotherapeutic agents. Anat Rec (New Anat) 261:14-24, 2000.

Animals↗

PubMed1988

Direct observation of mitotic spindle elongation in vitro.

Successful reactivation in vitro of anaphase B has recently been achieved with mitotic spindles isolated from the diatom Stephanopyxis turris. When a population of isolated spindles was studied indirectly by using immunofluorescence, nearly all of them were found to have elongated; however, when studied directly by using video microscopy, only a small proportion of spindles elongated. We report here conditions that allow nearly all of the spindles to elongate when observed directly with video microscopy. These direct observations validate previous ones made using indirect immunofluorescence. In addition, we find that the isolated spindles elongate with a linear rate, that the elongation is unchanged after the chromatin surrounding the spindles is digested with DNase I, and that during elongation a phase-dense matrix may accumulate in the spindle midzone.

Anaphase↗

PubMed1988

Cell-cycle modulation of MPM-2-specific spindle pole body phosphorylation in Aspergillus nidulans.

MPM-2 is a monoclonal antibody that interacts with mitosis-specific phosphorylated proteins in many different organisms. Immunocytochemistry of tissue culture cells has shown that MPM-2 stains centrosomes, chromosomes, kinetochores, and spindles. In this paper, we demonstrate that MPM-2 staining colocalizes with the spindle pole body (SPB) of Aspergillus nidulans and that SPB staining varies during the mitotic cycle. In an unsynchronized population, about one-fourth to one-third of the cells stain with MPM-2 at the spindle plaques or SPBs. Nuclei in mitosis have two SPBs localized at the ends of the spindle, both of which stain with MPM-2. To determine when MPM-2 staining appears, we have examined the effects of temperature-sensitive cell-cycle mutations that block nuclear division in S or G2. Only a very small fraction of cells blocked in S-phase stain with MPM-2. In contrast, a large fraction of cells blocked in G2 stain brightly at the SPB. These data suggest that MPM-2 reactivity of SPBs appears in G2. Moreover, the fact that cells blocked in G2 showed MPM-2 staining but no spindles suggests that reactivity of SPBs occurs prior to mitosis but is not sufficient to trigger spindle formation. When G2-blocked cells were downshifted to permissive temperature, they generated a mitotic spindle with an SPB at each end. Both SPBs stained with MPM-2 in all of the mitotic cells.

Antibodies, Monoclonal↗