TMIC-16. THE EXPRESSION OF CX43 AND GAP43 AS CELL-TO-CELL LINKING FACTORS WITHIN THE GROUP OF DIFFUSE AND ANAPLASTIC GLIOMAS

INTRODUCTION The diversity of expansion and resistance within the group of diffuse and anaplastic gliomas might be possible due to variations in the cell-to-cell communication, determined by the Cx43- junctional activity and microtubules-defined networking with GAP43 as the main structural component. The aim of our trial was to assess the expression of these crucial proteins in samples of patients. METHODS Tissue of adult patients with WHO°II and III gliomas, who underwent surgery 2014 to 2018, were selected from institutional biobank. The expression was analyzed using immunohistochemistry and routine findings gained from patient charts. RESULTS 43 (57%) males and 33 (43%) females with a median age of 47 years (IqR: 35–61) were analyzed. In 15 (20%) patients a diffuse glioma (WHO°II) and in 46 (60%) an anaplastic glioma (WHO°III) was diagnosed. Further 15 patients (20%) were diagnosed with a diffuse glioma showing focal anaplasia. The IDH1 wildtype tumors demonstrated higher Cx43 expression in patients with longer intervals between imaging-based diagnosis and biopsy (p=0.032), whereas this association was absent in IDH1 mutated gliomas (p=0.549). The IDH1 wildtype tumors showed a higher expression of Cx43 (p=0.003) and a trend towards higher expression of GAP43 (p=0.075). Advanced Cx43 expression correlated with lower Ki67 nuclear expression in both IDH1 wildtype (p=0.003) and mutated gliomas (p=0.019). DISCUSSION The IDH1 wildtype gliomas showed advanced expression of Cx43 and GAP43 as well as longitudinal increase of Cx43. In the same time, tumors with lower mitosis rate produced more communication proteins, probably due to longer interphase. It can be interpreted as the intercellular networking provides acquired pathogenicity in the tumors with lower, e.g. “favorable”, proliferation rate. Moreover, IDH1 wildtype gliomas showed here advanced results, matching their aggressive behavior and poor outcome. Thus, diffuse and anaplastic gliomas are not homogenic and need to be evaluated considering their genetic profile.

The role of mitosis in LDL transport through cultured endothelial cell monolayers

We ( 7 ) have previously shown that leaky junctions associated with dying or dividing cells are the dominant pathway for LDL transport under convective conditions, accounting for >90% of the transport. We ( 8 ) have also recently shown that the permeability of bovine aortic endothelial cell monolayers is highly correlated with their rate of apoptosis and that inhibiting apoptosis lowers the permeability of the monolayers to LDL. To explore the role of mitosis in the leaky junction pathway, the microtubule-stabilizing agent paclitaxel was used to alter the rate of mitosis, and LDL flux and water flux ( Jv) were measured. Control monolayers had an average mitosis rate of 0.029%. Treatment with paclitaxel (2.5 μM) for 1.5, 3, 4.5, or 6 h yielded increasing rates of mitosis ranging from 0.099% to 1.03%. The convective permeability of LDL (Pe) increased up to fivefold, whereas Jv increased up to threefold, over this range of mitosis rates. We found strong correlations between the mitosis rate and both Pe and Jv. However, compared with our previous apoptosis study ( 8 ), we found that mitosis was only half as effective as apoptosis in increasing Pe. The results led us to conclude that while mitotsis-related leaky junctions might play a role in the initial infiltration of LDL into the artery wall, the progression of atherosclerosis might be more closely correlated with apoptosis-related leaky junctions.

Indications of Sentinel Node Biopsy in Thin Melanoma

ABSTRACT Objective: To assess data on survival, recurrence and histological factors in positive and negative sentinel lymph nodes in thin melanoma cases. Methods: A systematic review was conducted on observational studies in four databases (Cochrane Library, Medline, Embase and Lilacs). Positive and negative micrometastases in sentinel lymph node biopsy were compared regarding the clinical outcomes – death and recurrence – and six histological factors – vertical growth phase, Breslow thickness, Clark level, ulceration, regression and mitosis rate. Results: Positive sentinel lymph node is statistically associated with greater risk of death in six studies (OR: 7.2; 95%CI [2.37-21.83]; I2 0%) and also to recurrence in three studies (OR: 30.7; 95%CI [12.58-74.92]; I2 36%). Comparing positive and negative groups, the histological factors predicting positive sentinel nodes and poor prognosis were: mitosis rate ≥ 5/mm2 (OR: 16.29; 95%CI [3.64-72.84]; I2 40%); VGP (OR: 2.93; 95%CI [1.08-7.93]; I2 59%); Breslow thickness ≥ 0.75mm (OR: 2.23; 95%CI [1.29-3.86]; I2 0%); and Clark level IV-V (OR: 1.61; 95%CI [1.06-2.44]; I2 34%). Conclusions: The statistically significant results associated with the presence of micrometastases in thin melanomas were Breslow thickness ≥ 0.75 mm, Clark level IV-V and mitoses ≥ 5/mm2, absence of regression. This histological factor of ulceration was associated, but not statistically significant.

The Diurnal Variations in the Tissue Glycogen Content and Their Relation to Mitotic Activity in the Adult Male Mouse

1. A description is given of the hour-to-hour variation in the liver glycogen content in adult male mice, and it is shown that the concentration is highest while the animals are asleep and lowest while they are awake. 2. A similar cycle is also described in the glycogen content of the skin. Histologically it is shown that a high proportion of the skin glycogen lies in the cytoplasm of the epidermal cells, and that during sleep both the epidermal glycogen content and the epidermal mitotis rate increase considerably. The skin glycogen content and the epidermal mitotic activity also show a marked increase after a subcutaneous injection of 20 mg. starch, while they are both abnormally depressed after two injections of 1/50 unit insulin. 3. These results, together with others previously reported, are in agreement with the theory that at the onset of sleep glucose is deposited from the blood into the tissues where it appears in the form of glycogen. Since it is known that glucose, or glycogen, is a critical substance affecting mitotic activity in the adult mouse, it is logical to find that an increase in the epidermal glycogen content is accompanied by a greatly increased mitosis rate. On waking, the reverse process takes place, glycogen being withdrawn as glucose into the blood and mitotic activity falling to a low level.

Age and Mitotic Activity in the Male Mouse, Mus Musculus L

1. A study has been made of the mitosis rate and of the diurnal cycles of male mice during each of the first 20 months of life. The mice used belonged to the Kreyberg's white label and the Strong's CBA strains. Most of the observations were made on the ear epidermis, but some attention was also given to other tissues. 2. It was discovered that, when judged from the point of view of mitotic activity, the life of a male mouse consists of four ages. During the immature age the animals are still growing and their mitosis rate is generally high, although the ear epidermis provides an exception to this rule. During the mature age which lasts from about the 3rd to the 12th month the mitosis rate is lowered. During the middle age which follows the mitosis rate increases, but in senility it is again reduced. 3. Coincident with these changes in the mitosis rate are changes in the spontaneous bodily activity. The mice are most active during immaturity and maturity. In middle age their activity is reduced by about half, and in senility they spend almost the whole time resting. Particularly in the Strong's CBA mice there are also changes in the timing of the diurnal cycle of spontaneous bodily activity, and these are immediately mirrored by changes in the timing of the diurnal cycle of mitotic activity so that throughout life a general inverse relationship between bodily activity and mitotic activity is maintained. 4. In middle-aged Strong's CBA males the daily rest period extends almost without interruption from 06.00 to 18.00 hr. However, the most active cell division develops only at the beginning of this period, and it is evident that in prolonged sleep a lack of some vital factor develops. It is shown that subcutaneous injections of starch overcome this lack in sleeping mice and result almost immediately in the redevelopment of a high mitosis rate. Thus it would appear that sugar is the vital factor involved, and that the sugar content of the tissues is quickly used up during high mitotic activity. 5. These results are discussed particularly in relation to the problem of carcinogenesis.

The Relation Between the Epidermal Mitotic Activity and the Blood-Sugar Level in the Adult Male Mouse, Mus Musculus L

1. An investigation has been made of the relation between the concentration of the blood sugar and the mitotic activity of the ear epidermis of the adult male mouse. It has been shown that, within limits, an increase in the blood-sugar level, induced by subcutaneous injections of starch, results in an increased mitosis rate. Conversely, a decrease in the blood-sugar level, induced by insulin, causes a decreased mitosis rate. A deep mitosis depression is also caused by injections of phloridzin. 2. Since it is known that phloridzin interferes with the phosphorylation of sugar, and since it is also shown that injections of phosphate augment the effect produced by starch alone, the tentative suggestion is put forward that sugar may act by satisfying the energy requirements of mitosis. 3. However, in the normal animal the diurnal changes in the blood-sugar level are the inverse of the diurnal changes in mitotic activity, the concentration of the blood sugar being relatively low during sleep when the mitosis rate is relatively high. It is therefore evident that, within normal limits, the level of the blood sugar as such is not an important factor in the control of the diurnal mitosis cycles. 4. It is considered probable that the critical factor in the control of these cycles is the concentration of sugar, or glycogen, within the tissues themselves. Thus during sleep, sugar is probably deposited in the tissues, as it is known to be in the liver, so accounting simultaneously for the fall in the level of the blood sugar and the rise in the mitosis rate.

The effects of experimentally induced rest and exercise on the epidermal mitotic activity of the adult male mouse, Mus musculus L

As a preliminary study of the conditions which affect the hour to hour variations in epidermal mitotic activity in the adult male mouse, experiments were carried out involving artificially induced sleep and exercise. In the first experiment the animals were injected with a dose of barbiturates sufficient to induce sleep for a period of 3 or 4 hr. at a time of day when they were usually active. The injections were given at 17.00 hr. as the animals were waking from their afternoon sleep, and they resulted in a sharp rise in mitotic activity. A maximum was reached at 20.00 hr., the time when the mitotic activity of the controls had dropped to a minimum. As the animals recovered and became active, their mitosis rate fell quickly to a low level. In the second experiment the animals were placed in a slowly revolving box, and so forced to remain awake and active throughout an afternoon when they would otherwise have been asleep. This treatment resulted in extremely low mitotic activity, in contrast to which that of the normally sleeping controls rose to a high level. It is probably significant that when the mice were released from the revolving box, and could at last sleep, their mitosis rate remained low. This suggests that the excessive exercise had either resulted in the production of some mitosis-depressing substance which remained in the system, or that some substance vital to mitosis had been used up and took some time to be replaced. The conclusion is now justified that the rate of epidermal mitosis normally increases during sleep, and decreases during hours of wakefulness and exercise. In this way the form of the diurnal mitosis cycle is determined by the habits of the animals.

AN ANALYSIS OF MITOSIS IN LIVER RESTORATION

1. Following partial hepatectomy in the rat, there is a latent period of 1 day during which the rapidly growing organ shows no increase in cell number. Mitosis then begins rapidly, following a brief pre-mitotic period of visible nuclear changes. 2. It can be shown that the increase in cell number during the ensuing 48 hours follows a formula of the type dN/dt = ke-kt., beyond this time it is retarded more than this simplified formula would predict. The average mitosis rate at 1, 2, and 3 day intervals after operation follows the same formula; from this the duration of each mitosis is calculated to be about 49 minutes. It is not necessary to assume that amitotic division plays an important part, and no such divisions have been seen by the writers. 3. The percentage of cells in mitosis in a single hypertrophying liver varies widely from hour to hour, so that a single mitosis count tells nothing about the growth rate. The fluctuations occur at different times in different livers. It appears that no great number of mitoses begin or end simultaneously. 4. Mitoses are evenly distributed throughout the liver and throughout each lobule; there is no preponderance near the bile duct cells. 5. The mean initial mitosis rate (at 24 hours after operation) is 2.13 per cent, and it diminishes from then on. This rate is very similar to that in early embryo heart and tissue cultures of mesenchyme. In individual specimens the rate can be over 8 per cent. This rapid rate occurs without signs of cell dedifferentiation.