Normal Mitotic Figures Research Articles

Immunohistochemical Evaluation of Bcl-2 and Ki-67 in Buccal Mucosa of Induced- Immunosuppressed Albino Rats

Introduction: Organ transplantation provides life-saving therapy for patients with end-organ disease. Tacrolimus is an immunosuppressive drug used to lower the risk of organ rejection. This study was performed to investigate the immunohistochemical expressions of Ki-67 (a proliferation associated antigen) and Bcl-2 (antiapoptotic protein) and their correlation with the increased risk of development of neoplasms in the buccal mucosa of tacrolimus-induced immunosuppressed albino rats. Material & methods: Twenty adult male albino rats were divided into two equal groups. Group one treated with tacrolimus in a daily oral dose 0.5 mg/kg for 3 months. Group two served as negative control, received distilled water in comparable volume. Tissue samples were fixed in 10% formalin, embedded in paraffin, and stained with hematoxylin and eosin to evaluate histopathological finding. Other sections were used to reveal the immunohistochemical expression of Ki-67 and Bcl-2 antibodies through computerized image j analysis software. The expression of both markers was analyzed statistically through using Mann-Whitney test. Results: Histopathological finding showed moderate dysplasia in tacrolimus-treated group. There was marked increase in normal mitotic figures, basal cell hyperplasia, loss of basal cell polarity, swirling of the spinous layer, prominent nucleoli, hyperchromatism, and altered N/C ratio. Immunohistochemical finding revealed marked increase in the nuclear expression of Ki-67 in basal cells and cytoplasmic expression of Bcl-2 in all layers of keratinocytes in tacrolimus-treated group. Statistical finding in tacrolimus – treated group showed significant difference in the expression of Ki-67 and highly significant difference in the expression of Bcl-2. Conclusion: There is an obvious relation between prolonged systemic use of tacrolimus and development of premalignant lesions. The marked increase in Ki-67 and Bcl-2 expression may play a role in tumorgenesis.

Histopathological diagnosis of eyelid tumor in Moustached wren (Pheugopedius genibarbis SWAINSON, 1838) (Passeriforme, Troglodytidae). A case report.

The aim of this work was to describe an eyelid neoplasm in wild birds, since the veterinary literature has little information concerning the aspects of the oncologic clinic in wild species. In the clinical exam, it was observed a single mass in the upper right eyelid of the Pheugopedius genibarbis a, with rough surface, cauliflower aspect, of dark-red coloration . For the histopathological diagnosis, an incisional biopsy of the lesion was done , with the fragment fixed in 10% buffered neutral formalin, processed by the method of inclusion in paraffin , cut to 4µm sections and stained with H&E . The histopathological findings revealed elongated dermal papillae covered by acanthotic epidermis, as well as thickness of the stratum spinosum . In the stratum spinosum, it was observed the presence of cells with vacuolated cytoplasm and nucleus slightly dislocated to the center of the cell, which increases in proportion when closer to the granular layer, an indication of hydropic degeneration , there were In the basal layer it is possible to notice the presence of the normal mitotic figures.. Based on the macro and microscopic characteristics, that neoplasm was diagnosed as an eyelid papilloma.

Cancer Cell Nucleus: An Insight

Nucleus reflects a cell’s biological potential and activity. Nuclei of normal healthy cells are usually single per cell in number, round to oval shaped, show even distribution of chromatin, display regular nuclear margin or membrane, one or two inconspicuous nucleoli and normal mitotic figures. During development of cancer, the nucleus undergoes numerous alterations of size, shape, number, nuclear membrane or margin, chromatin pattern, nucleoli, and organization of nuclear chromatin.

Centrosome structure and function is altered by chloral hydrate and diazepam during the first reproductive cell cycles in sea urchin eggs

This paper explores the mode of action of the tranquillizers chloral hydrate and diazepam during fertilization and mitosis of the first reproductive cell cycles in sea urchin eggs. Most striking effects of these drugs are the alteration of centrosomal material and the abnormal microtubule configurations during exposure and after recovery from the drugs. This finding is utilized to study the mechanisms of centrosome compaction and decompaction and the dynamic configurational changes of centrosomal material and its interactions with microtubules. When 0.1% chloral hydrate or 350-750 microM diazepam is applied at specific phases during the first cell cycle of sea urchin eggs, expanded centrosomal material compacts at distinct regions and super-compacts into dense spheres while microtubules disassemble. When eggs are treated before pronuclear fusion, centrosomal material aggregates around each of the two pronuclei while microtubules disappear. Upon recovery, atypical asters oftentimes with multiple foci are formed from centrosomal material surrounding the pronuclei which indicates that the drugs have affected centrosomal material and prevent it from functioning normally. Electron microscopy and immunofluorescence studies with antibodies that routinely stain centrosomes in sea urchin eggs (4D2; and Ah-6) depict centrosomal material that is altered when compared to control cells. This centrosomal material is not able to reform normal microtubule patterns upon recovery but will form multiple asters around the two pronuclei. When cells are treated with 0.1% chloral hydrate or 350-750 microM diazepam during mitosis, the bipolar centrosomal material becomes compacted and aggregates into multiple dense spheres while spindle and polar microtubules disassemble. With increased incubation time, the smaller dense centrosome particles aggregate into bigger and fewer spheres. Upon recovery, unusual irregular microtubule configurations are formed from centrosomes that have lost their ability to reform normal mitotic figures. These results indicate that chloral hydrate and diazepam affect centrosome structure which results in the inability to reform normal microtubule formations and causes abnormal fertilization and mitosis.

Atypical mitotic figures and the mitotic index in microinvasive carcinomas and in non-neoplastic changes of the uterine cervix

SummaryThis study sought to show whether an increased mitoticindex (MI; i.e. the number of mitoses among 1000 nuclei) and the occurrence of particular atypical mitotic figures (AMFs) are characteristic of cervical squamous malignancy.The study group consisted of 24 cervical tissue specimens with microinvasive carcinoma (MIC). The intraepithelial and invasive parts were considered separately. The control group consisted of 82 cervical tissue specimens without neoplasia which were derived from two sources: 31 women were biopsied because of an abnormal cervical cytology report but no neoplasia was found histologically and 51 women underwent an hysterectomy for non-cervical uterine disease. Mitoses were only classified in proliferative lesions (MI⩾2). The mitoses were classified into normal mitotic figures (NMFs), lag type mitoses (LTMs), multipolar mitoses (MPMs) and other atypical mitotic figures (OAMFs). Particular attention was given to the two group metaphase (2GM), a member of the LTMs. In order to be 9...

Atypical mitotic figures and the mitotic index in cervical intraepithelial neoplasia.

We surveyed cervical intraepithelial neoplasia (CIN) to quantify the proliferation rate and the presence of normal and atypical mitotic figures. In the cervical tissue specimens of 127 women with CIN, the area with the highest cell proliferation was identified and, at that site, the proliferation rate was assessed by calculating the mitotic index (MI). Lesions with an MI < 2 were not considered further. In the area with the highest proliferation rate, 228 mitoses were classified into one of the following groups: normal mitotic figures (NMFs), lag-type mitoses (OLTMs) comprising three group metaphases (3GMs), two group metaphases (2GMs) and other lag-type mitoses (LTMs), multipolar mitoses (MPMs) comprising tripolar mitoses (3PMs) and quadripolar mitoses (4PMs), and other atypical mitotic figures (OAMFs). The median value of the MI increased significantly from 3 in CIN I through 4 in CIN II to 9 in CIN III (P < 0.001). The occurrence of the different LTMs was mutually correlated. The frequency of LTMs increased significantly with increasing CIN grade (P < 0.001), whereas the frequency of NMFs decreased significantly with increasing CIN grade (P < 0.001). The frequency of OAMFs was not related to CIN grade (P = 0.94). MPMs were present in low numbers in a minority of the lesions. Spearman's rank correlation coefficient (with 95% confidence limits) between the MI and the number of LTMs, OAMFs and NMFs was 0.66 (0.53; 0.75), -0.14 (-0.32; 0.05) and -0.51 (-0.63; -0.35), respectively. Increasing CIN grade is associated with increasing MI, increasing numbers of LTMs, and decreasing numbers of NMFs. MPMs are very rare events in CIN. The abundant presence of OAMFs seems to be independent of CIN grade and MI.

Effects of zarilamide on microtubules and nuclear division in Phytophthora capsici and tobacco suspension-cultured cells

Zarilamide inhibited nuclear division in germinating zoospore cysts of Phytophthora capsici at concentrations which caused only partial inhibition of growth. Morphological effects and inhibition of germ tube elongation occurred after nuclear division had been arrested. Mitosis was arrested very rapidly after adding the compound to germlings about to undergo their first nuclear division, and this was accompanied by destruction of the microtubule cytoskeleton as revealed by immunofluorescence microscopy. The antimicrotubule agent colchicine caused similar effects to those of zarilamide on nuclear division, germ tube morphology, and microtubules in P. capsici. Zarilamide inhibited growth of tobacco roots and caused swelling of the root tips. In tobacco suspension-cultured cells zarilamide produced an accumulation of cells in arrested metaphase, the absence of normal mitotic figures, and the disappearance of both cortical and spindle microtubules. These results suggest that the mechanism of action of zarilamide in P. capsici and tobacco involves destruction of the microtubule cytoskeleton, and a consequent inhibition of mitosis.

Immunofluorescence and electron microscopic investigations of the effects of dithiopyr on onion root tips

Light, immunofluorescence, and electron microscopy are used to investigate the effects of dithiopyr [ S,S-dimethyl 2-(difluoromethyl)-4-(2-methylpropyl)-6-(trifluoromethyl)-3,5-pyridine-dicarbothioate] on onion root meristems. At high herbicide concentrations (10 −4, 10 −5 M) all of the dividing cells are in an arrested prometaphase configuration although, at lower concentrations (10 −6, 10 −7 M), multipolar mitosis, along with some apparently normal mitotic figures, also are noted. Immunofluorescence microscopy reveals that nearly all of the microtubules are absent after treatment with high concentrations of herbicide, although small tufts of microtubules remain at the kinetochore. These kinetochore tufts are confirmed to be microtubules (and not just aggregates of tubulin protein) by electron microscopic analysis. Phragmoplast arrays are absent at these higher concentrations and no cell plates are formed. Nuclei that reform after the arrested prometaphase or multipolar division are irregularly formed, either highly lobed or fragmented into multiple nuclei. Branched and undulating phragmoplast microtubule arrays oriented in abnormal directions are observed frequently after 10 −6 M treatment. The walls that result from these abnormal phragmoplasts are also unusual. Branched walls, multiple walls/cell, walls with electron opaque depositions, and incomplete reticulate walls are also noted. Because dithiopyr does not bind tubulin, we propose that this herbicide destabilizes microtubules as they are formed so that only short microtubules result. These shortened, destabilized microtubules are ineffective in chromosome movement during mitosis or other cellular functions involving microtubules. Thus, the net effects of dithiopyr are similar to those compounds that cause complete microtubule loss, such as trifluralin or amiprophosmethyl, even though the mechanism of disruption is different.

Histological study of the regrowth of a human melanoma xenograft exposed to single dose irradiation

The aim of this investigation was to find the location and the histological characteristics of cells that were the source of tumour regrowth after single dose irradiation. A human melanoma xenograft was irradiated with a single dose of 25.0 Gy which gives local tumour control in nearly 50% of treated animals. Serial histological sections were made from tumours removed during the first two weeks after irradiation. During the first week the perivascular organization of tumour parenchyma disappeared and the central part of the tumour became necrotic. The occurrence of vascular stasis, thrombosis and endothelial cell changes indicated that radiation injury to the vascular system was involved in the disappearance of the tumour cords. Tumour cells that remained histologically intact were located in subcapsular areas. The incidence of normal mitotic figures increased, and the fraction of abnormal mitoses and the incidence of micronuclei decreased 5 to 7 days before macroscopical regrowth was usually detected. It is concluded that cells which are the source of tumour regrowth were located in the subcapsular areas at the time of irradiation. Radiation injury to the tumour vascular system was an important factor in the necrotization of the tumour centre after treatment.

Chromosome abnormalities in mice with Hertwig's anemia

Mice with the recessive hereditary disease, Hertwig's anemia (an/an), exhibit a persistent mild macrocytic anemia and reduced fertility. We examined mitotic figures from bone marrow and kidney cells of adult mice and from liver cells of fetal mice that were genetically normal or had Hertwig's anemia. Uniformly normal mitotic figures were observed in the nonanemic mice (+/+ or +/an). In contrast, 5% to 15% of the mitotic figures were abnormal in mice homozyous for Hertwig's anemia (an/an). These aberrant cells were hyperploid, containing more than the normal complement of c40 chromosomes, but fewer than 80 chromosomes. Cells with abnormal numbers of chromosomes may show decreased viability or proliferative capacity. The occurrence of such abnormal cells in an/an mice could explain (1) the loss of progenitor stem cells during erythroid maturation, resulting in an anemic phenotype; and (2) the depletion of germ cells during ontogeny, resulting in reduced fertility.

Chromosome Abnormalities in Mice With Hertwig's Anemia

Mice with the recessive hereditary disease, Hertwig's anemia (an/an), exhibit a persistent mild macrocytic anemia and reduced fertility. We examined mitotic figures from bone marrow and kidney cells of adult mice and from liver cells of fetal mice that were genetically normal or had Hertwig's anemia. Uniformly normal mitotic figures were observed in the nonanemic mice (+/+ or +/an). In contrast, 5% to 15% of the mitotic figures were abnormal in mice homozyous for Hertwig's anemia (an/an). These aberrant cells were hyperploid, containing more than the normal complement of c40 chromosomes, but fewer than 80 chromosomes. Cells with abnormal numbers of chromosomes may show decreased viability or proliferative capacity. The occurrence of such abnormal cells in an/an mice could explain (1) the loss of progenitor stem cells during erythroid maturation, resulting in an anemic phenotype; and (2) the depletion of germ cells during ontogeny, resulting in reduced fertility.

Positional information and pattern regulation in hydra: the effect of γ-radiation

ABSTRACT Hydra exposed to high doses of γ-irradiation (25000 rad) are still capable of regeneration although no normal mitotic figures could be seen for up to 48 h after irradiation. Irradiated heads could still inhibit head formation in other regions in graft combinations. The time for head end determination in irradiated animals appeared to be increased. It is concluded that head end regeneration need not involve cell division.

Effect of fluorodeoxyuridine, colcemid, and bromodeoxyuridine on developing neocortex of the mouse

AbstractThe purpose of this study was to obtain information about factors controlling the interkinetic movement of neuroepithelial cells and the cortical migration of neuroblasts in the developing mouse neocortex. In the first experiment 15‐day pregnant mice were injected with a single dose of fluorodeoxyuridine, a compound which inhibits the enzyme thymidylate synthetase thus blocking DNA‐replication. The animals were sacrificed at various hours and days following treatment. Two hours after treatment the mitotic index of the neuroepithelial cells was severely reduced and cells with abnormal nuclei appeared in the DNA‐synthesizing zone of the neuroepithelial layer. By five hours more abnormal cells appeared and many showed degenerating nuclei. By 12 hours cells with abnormal nuclei were seen in the outer half of the neuroepithelial layer and some in the migratory zone. Since they were not seen at the lumen, these observations indicate that fluorodeoxyuridine‐affected nuclei do not move to the lumen and do not divide. By 24 hours abnormal nuclei were seen in the migratory zone and cortical plate suggesting cortical migration without preceding cell division. In the second experiment 15‐day pregnant mice were treated with col‐cemid, a compound which arrests dividing cells in metaphase. Two and four hours after injection a large number of neuroepithelial cells in metaphase accumulated at the lumen. By seven and 12 hours the number of arrested metaphases decreased rapidly, but at the same time cells with dense, darkly stained nuclei appeared in the adjacent neuroepithelium. By 24 hours these abnormal nuclei were present in the migratory zone and cortical plate, suggesting that they were migrating towards the surface of the cortex despite the failure to complete mitosis. In the third experiment 15‐day pregnant mice were injected with bromodeoxyuridine, a compound incorporated into DNA and thought to interfere with differentiation. During the first 12 hours after treatment a striking increase in the number of normal mitotic figures was seen at the lumen. By 16 hours, however, abnormal mitotic figures started to appear. Since the generation time of neuroepithelial cells at this stage of development is about 13 hours, the abnormal mitotic figures must represent cells which have gone through two DNA‐synthetic periods since the beginning of the treatment. The abnormal mitotic figures give rise to cells with dense pycnotic nuclei which by 24 hours are found throughout the width of the developing neocortex. Thus in each experiment cells with abnormal, presumably non‐functional, nuclei were produced. Despite the failure to divide or to carry out a normal division, the nuclei migrate from the neuroepithelial layer towards the cortical plate in a fashion similar to that of normal postmitotic neuroblasts.

Active epidermal movement in human skin in vitro.

Epidermal cells migrate from the edges of adult human skin in culture during the first 48 h. In order to determine whether mitotic acitivity was responsible for this cell movement the autoradiographic labelling index for cells in DNA synthesis was determined for skin at different stages of culture. The labelling index of skin maintained for 48 h but labelled with tritiated thymidine in the first 4 h, did not differ significantly from skin both maintained and labelled for 4 h only. Skin maintained for 48 h but labelled in the last 4 h showed a much lower labelling index. No normal mitotic figures were seen in the epidermis of skin maintained for 48 h but exposed to colcemid for the last 4 h of culture. It has been concluded that at least in short-term organ culture of adult human skin there is a phase of mitotic arrest and that epidermal migration during the first 48 h is an active process independent of mitotic activity.

Cerebral cortex of the mouse after prenatal chemical insult.

AbstractThe purpose of this study was to examine whether a short term chemical insult to neuroepithelial cells (the matrix cells of neurons) causes a clearly defined neuronal deficit in the neocortex and hippocampal region. In the first experiment 15‐day pregnant mice were given a single dose of 5‐azacytidine (4 mg/kg); 30–60 minutes later they were injected with tritiated thymidine (6 μc/g). The fetuses were sacrificed at various hours and days after treatment. No cellular abnormalities were observed one or two hours after treatment with 5‐azacytidine, but at three to four hours abnormal mitotic figures became visible at the lumen. Usually the chromosomes were clumped together, forming commaand circle‐shaped structures. Sometimes chromosome breaks were observed. The number of cells with chromosomal abnormalities increased during the following hours, but ten hours after treatment a few normal mitotic figures appeared again. In the meantime the affected cells moved from the lumen toward the cortical plate. Their number gradually decreased and 48 hours after treatment all had disappeared. Since in the controls many labeled cells reached the cortex but in the experimental animals none, a neuronal deficit resulted from the treatment. It was difficult, however, to pinpoint the type of neuron lacking in the brain of the treated newborn. In the second experiment pregnant animals were given several doses of 5‐azacytidine (2 mg/kg on days 13, 14 and 15 of gestation) and sacrificed at various days after birth. The neocortex as well as the hippocampal region of the treated animals contained fewer cells than the same structures in the controls. In addition many neurons both in the cortex and hippocampus were morphologically abnormal. It is thus concluded that single and repeated shortterm chemical insults to neuroepithelial cells during the later stages of fetal life, result in a shortage of neurons and the presence of morphologically abnormal neurons.

THE DURATION OF MITOSIS IN THE CRYPTS OF LIEBERKÜHN OF THE TERMINAL ILEUM OF THE ALBINO RAT

ABSTRACTThe duration of mitosis in the epithelium of the terminal ileum of the adult rat has been determined by counting normal mitotic figures, and colchicine‐metaphases, in Feulgen‐stained squashes of whole, micro‐dissected crypts of Lieberkühn. The duration, which depends on the morphological definition of mitosis adopted, was calculated to be 23 min.This value is similar to those determined by other authors using other methods, except in the case of tritiated‐thymidine autoradiography, where the reported duration of mitosis is considerably longer. The possibility that this is due to an effect of thymidine on mitosis is discussed.

Postmortem mitotic activity of spermatogonia and spermatocytes in the albino rat

1. 1. In the rat spermatogonial mitoses can be found in all phases, and in normal or slightly above normal numbers for 8 hours after death of the animal. Prophases disappear after this time. Sixteen hours after death no normal spermatogonial mitoses are seen. The type A spermatogonia show normal mitotic figures for a longer time than the type B cells. 2. 2. Mitoses of the primary spermatocytes are found in normal numbers up to 16 hours postmortem. At this time only a few prophases are present. 3. 3. Secondary spermatocytes ordinarily do not enter prophase after the second hour postmortem. 4. 4. It is concluded that spermatogonia and primary spermatocytes can survive and show mitotic activity for many hours after death under definitely anaerobic conditions. They may, therefore, be added to the list of cells known to survive under conditions of relative or absolute oxygen deprivation; i.e. certain protozoa, the cells of certain invertebrates, certain embryonic cells and certain malignant tumor cells.

Somatic Mutations as a Factor in the Production of Cancer: A Critical Review of v. Hansemann's Theory of Anaplasia in the Light of Modern Knowledge of Genetics

For nearly thirty years the phenomenon known by von Hansemann9s term, anaplasia, has been widely used among pathologists to describe and explain the origin of cancer cells. Any well established facts, therefore, which throw added light upon the nature of the process of anaplasia itself and any possible relation it may have to cancer genesis must be important and significant. The term anaplasia has been, however, so loosely used that it will be worth while to review at length von Hansemann9s theory in order that we may start with a clear conception of what the word really means. The pleomorphism of cancer cells and the irregular, atypical mitoses so characteristic of their nuclei had been observed and carefully studied since the middle of the nineteenth century. Arnold (Virch. Arch., vol. 79, cited by von Hansemann (1)), observing irregularities in the mitotic process itself, had inferred that these might be of fundamental significance. A voluminous literature dealing with the mitoses in cancer cells and other forms of rapidly proliferating tissues had already accumulated when von Hansemann (1) undertook a further investigation in the same field. In a carcinoma of the larynx he found besides a great abundance of normal mitotic figures, large numbers of tripolar and multipolar divisions and other departures from the normal type already observed and described by earlier writers; and in addition many hyperchromatic and hypochromatic mitoses, the hypochromatism consisting not merely in a reduction of the amount of chromatin in the chromosomes but rather in an actual reduction of the total number of the chromosomes. He reproduces a monaster with only nine chromosomes. Further search led to the finding of a hypochromatic diaster one member of which contained five chromosomes, the other eight, or possibly nine. This asymmetry of division, which he regarded as analogous to the process by which he believes that differentiation, or specialization of the cells occurs during normal embryonic development, might, he thought, take place either as the result of delay, or of complete failure of the chromosomes to split longitudinally during the mitotic process; or else through failure of the two longitudinal halves of the chromosomes to separate and pass to the opposite ends of the spindle. In one of his cases he found numerous instances in which, in the monaster stage, late in the metaphase, (or telophase), the chromosomes were found lying in pairs close to and parallel with one another, indicating that splitting had occurred shortly before. Since splitting normally occurs early in the anaphase, he inclines to the view that the asymmetry in question is due to delayed splitting, at least in some instances.