Markers of Cardiotoxicity in Early Breast Cancer Patients Treated With a Hypofractionated Schedule: A Prospective Study.

PURPOSE: To evaluate, in a series of early breast cancer (BC) patients treated with hypofractionated adjuvant radiotherapy (RT), whether N-terminal-pro hormone B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin I assay measurements can predict acute clinical or preclinical cardiotoxicity. PATIENTS AND METHODS: The study comprised 44 consecutive patients, who underwent conservative surgery with or without (neo)adjuvant chemotherapy and hypofractionated adjuvant RT. The RT schedule consisted in a total dose of 42.4 Gy in 16 fractions administered 5 days per week. Twenty-one patients received a subsequent boost to the tumor bed consisting of a total dose of 10 Gy in 4 fractions delivered via a direct electron field. All patients underwent 12-lead electrocardiogram, echocardiogram, and cardiac clinical examinations before RT to assess cardiovascular risk factors; these examinations were repeated yearly for 5 consecutive years. High-sensitivity cardiac troponin I and NT-proBNP were analyzed from serum samples at baseline, after delivery of the fourth and 16th RT fractions, and 12 months after treatment completion. RESULTS: No increase in cardiac troponin I and B-type natriuretic peptide levels related to left breast irradiation was observed. No statistical difference in NT-proBNP and high-sensitivity troponin I levels between left- and right-sided BC was found. An increase was observed of B-type natriuretic peptide levels at baseline, during treatment, and until 12 months after RT related to hypertension, with the P value near to the .05 threshold for age and chemotherapy. CONCLUSION: Conformational hypofractionated RT in left-sided BC may not cause acute myocardial damage. Early cardiac screening may be used to identify patients with cardiologic risk factors, patients who are older than 60 years, and patients who received chemotherapy that could result in clinically relevant cardiac pathologies.

Persistently decreased hepatic levels of 5'-deoxy-5'-methylthioadenosine during regeneration of and chemical carcinogenesis in rat liver.

The hepatic levels of 5'-deoxy-5'-methylthioadenosine (MTA) were measured in the livers of adult male Sprague-Dawley rats a) killed at various times during the liver regeneration process, b) killed at times after partial hepatectomy when the liver mass had already been completely restored (hereafter called post-regeneration livers), or c) continuously fed 3'-methyl-4-dimethyl-aminoazobenzene (CAS: 55-80-1) up to the full development of hepatoma and killed at regular intervals during hepatocarcinogenesis. Hepatic MTA levels were always significantly decreased, although to different degrees in both in vivo models of hepatic growth and at all times during the investigation. Astonishingly, the MTA levels were also significantly decreased in the post-regeneration livers, in which there was also a significant increase in the activity of adenosylmethionine decarboxylase (S-adenosyl-L-methionine decarboxylase; EC 4.1.1.50) with normal levels of activity of ornithine decarboxylase (EC 4.1.1.17). These results demonstrate that a) the MTA content is always decreased in rat liver whenever this organ is involved in a proliferative process (whether controlled or uncontrolled); b) the decrease in hepatic MTA content is a biochemical feature necessary for, but by no means by itself sufficient for, hepatocyte proliferation to occur, since this decrease remains long after complete restoration of the liver mass; and c) the return of the hepatocytes to the normal biochemical program after restoration of the liver mass is not complete, even though these cells become quiescent, because there are still some biochemical abnormalities in the post-regeneration livers.

Degrees of malignancy in human primary central nervous system tumors: ornithine decarboxylase levels as better indicators than adenosylmethionine decarboxylase levels.

The levels of activity to ornithine decarboxylase (ODC) and adenosylmethionine decarboxylase (AMD) were measured in various types of primary human tumors of the central nervous system (CNS) and whenever possible were related to the malignancy of the tumor graded according to histopathologic criteria. In astrocytomas ODC levels increased linearly and progressively from infratentorial pilocytic astrocytoma (grade I) to glioblastoma multiforme (grade IV) and corrected well with the degree of histologic malignancy of the tumor. AMD activity levels, however, correlated with tumor malignancy only up to grade III astrocytoma. Medulloblastomas exhibited an unusual dichotomy with regard to the levels of polyamine biosynthetic decarboxylases (PBD): Medulloblastomas had the highest ODC activities of all the CNS tumors tested but had low AMD activities. In tumors of neuroepithelial tissue ODC level increases and, when present, AMD level increases were not due to proliferation of new blood vessels, because CNS hemangioblastomas had very low levels of both PBD activities. No significant differences in either of the PBD levels were observed among the several variants of meningiomas tested, the meningotheliomatous, the transitional, and the fibrous meningiomas. However, atypical forms of meningioma, i.e., those with mitotic figures, whatever the histologic variants, had higher levels of ODC, but not of AMD, than the typical forms, i.e., those without mitotic figures.

Changes in th circadian rhythm of ornithine decarboxylase in rat liver during chemical hepatocarcinogenesis.

The chronobiology of ornithine decarboxylase (ODC) activity in livers was investigated in noninbred Sprague-Dawley rats fed for 5 months with a basal diet or diets with 3-methyl-4'-(dimethylamino)azobenzene (3-Me-DAB) that were oncogenic or caused bile duct hyperplasia (1-naphthylisothiocyanate) (NIT). After a transient disappearance of the ODC circadian rhythm during month 1 on the oncogenic diet, this rhythm in the livers of the rats was reestablished at 60 and 90 days and then disappeared for the next 2 months. When present, the ODC rhythm in 3-Me-DAB-treated rats had the same daily temporal pattern as that of the controls. In the livers of rats treated with NIT, the ODC circadian rhythm was never detectable, even after only 1 month of feeding. Generally, the 3-Me-DAB feeding induced higher levels of ODC activity than did the NIT feeding. The alternation of the appearance and the disappearance of ODC circadian rhythm might reflect changes in the cell population during neoplastic transformation. Te chronobiologic differences in ODC rhythm between the group fed 3-Me-DAB and the group fed NIT could be related to the different types of proliferating cells involved in the hepatic responses to the two drugs.

Specific inhibition of the synthesis of putrescine and spermidine by 1,3-diaminopropane in rat liver in vivo.

Chronic administration of 1,3-diaminopropane, a compound inhibiting mammalian ornithine decarboxylase (EC 4.1.1.17) in vivo, effectively prevented the large increases in the concentration of putrescine that normally occur during rat liver regeneration. Furthermore, repeated injections of diaminopropane depressed by more than 85% ornithine decarboxylase activity in rat kidney. Administration of diaminopropane 60 min before partial hepatectomy only marginally inhibited ornithine decarboxylase activity at 4 h after the operation. However, when the compound was given at the time of the operation (4 h before death), or any time thereafter, it virtually abolished the enhancement in ornithine decarboxylase activity in regenerating rat liver remnant. An injection of diaminopropane given 30 to 60 min after operation, but not earlier or later, depressed S-adenosyl-L-methionine decarboxylase activity (EC 4.1.1.50) 4 h after partial hepatectomy. Diaminopropane likewise inhibited ornithine decarboxylase activity during later periods of liver regeneration. In contrast to early regeneration, a total inhibition of the enzyme activity was only achieved when the injection was given not earlier than 2 to 3 h before the death of the animals. Diaminopropane also exerted an acute inhibitory effect on adenosylmethionine decarboxylase activity in 28-h regenerating liver whereas it invariably enhanced the activity of tyrosine aminotransferase (EC 2.6.1.5), used as a standard enzyme of short half-life. Treatment of the rats with diaminopropane entirely abolished the stimulation of spermidien synthesis in vivo from [14C]methionine 4 h after partial hepatectomy or after administration of porcine growth hormone. Both partial hepatectomy and the treatment with growth hormone produced a clear stimulation of hepatic RNA synthesis, the extent of which was not altered by injections of diaminopropane in doses sufficient to prevent any enhancement of ornithine decarboxylase activity and spermidine synthesis.

Low levels of cobalamin, epidermal growth factor, and normal prions in multiple sclerosis spinal cord.

We have previously demonstrated that multiple sclerosis (MS) patients have abnormal cerebrospinal fluid (CSF) levels of the key myelin-related molecules cobalamin (Cbl), epidermal growth factor (EGF), and normal cellular prions (PrP(C)s), thus confirming that some CSF abnormalities may be co-responsible for remyelination failure. We determined the levels of these three molecules in post-mortem spinal cord (SC) samples taken from MS patients and control patients. The control SC samples, almost all of which came from non-neurological patients, did not show any microscopic lesions of any type. All of the samples were supplied by the U.K. MS Tissue Bank. The Cbl, EGF, and PrP(C) levels were determined using enzyme-linked immunosorbent assays. The SC total homocysteine level was determined using a competitive immunoenzymatic assay. CSF samples, taken from a further group of MS patients, were used for the assay of holo-transcobalamin (holo-TC) levels. The Cbl, EGF, and PrP(C) levels were significantly decreased in MS SCs in comparison with controls and, paradoxically, the decreased Cbl levels were associated with decreased SC levels of homocysteine, a biochemical marker of Cbl deficiency. The trends of EGF and PrP(C) levels paralleled those previously found in CSF, whereas that of Cbl was the opposite. There was no significant difference in CSF holo-TC levels between the MS patients and the controls. Given that we have previously demonstrated that Cbl positively regulates central nervous system EGF levels, it is conceivable that the low EGF levels in the MS SC may be causally related to a local decrease in Cbl levels. Only PrP(C) levels were invariably decreased in both the SC and CSF regardless of the clinical course of the disease. These findings suggest that the simultaneous lack of Cbl, EGF, and PrP(C)s may greatly hamper the remyelination process in MS patients, because they are key molecules of the machinery for remyelination.

Levels of activity of the polyamine biosynthetic decarboxylases as indicators of degree of malignancy of human cutaneous epitheliomas.

The activities of ornithine decarboxylase and of S-adenosyl-L-methionine decarboxylase in human normal epidermis, in basal cell epitheliomas, and in squamous cell carcinomas of human skin have been compared. All 3 types of tissues have characteristic levels of each of these enzymes. The normal epidermis had the lowest levels of both ornithine decarboxylase and S-adenosyl-L-methionine decarboxylase activities. The levels of the polyamine biosynthetic decarboxylases in basal cell epitheliomas were significantly higher than those of normal epidermis, but at the same time significantly lower than those present in squamous cell carcinomas. These results support the conclusion that in epithelial malignant tumors of human skin the extent of the increase in the activities of polyamine biosynthetic decarboxylases is well correlated with the neoplasm's growth rate, which is faster in the squamous cell carcinomas than in the basal cell epitheliomas.

Further evidence for the involvement of epidermal growth factor in the signaling pathway of vitamin B12 (cobalamin) in the rat central nervous system.

In order to get further evidence for a mandatory involvement of epidermal growth factor (EGF) in the neutrophic action of vitamin B12 (cobalamin (Cbl)) in the central nervous system (CNS) of the rat, we observed the effects of repeated intracerebroventricular (ICV) microinjections of EGF in rats made Cbl-deficient through total gastrectomy. Morphometric analysis demonstrated a significant reduction in both intramyelinic and interstitial edema in the white matter of the spinal cord (SC) of totally gastrectomized (TGX) rats after treatment. Intramyelinic and interstitial edema are characteristic of Cbl-deficient central neuropathy in the rat. Similar lesions were also present in SC white matter of rats treated with repeated ICV microinjections of specific anti-EGF antibodies without any modification in their Cbl status. These results, together with those of a previous study showing the cessation of EGF synthesis in the CNS of TGX rats, demonstrate that: a) EGF is necessarily involved in the signaling pathway of Cbl in the rat CNS; and b) the lack of a neurotrophic growth factor EGF, and not the mere withdrawal of Cbl, causes or at least contributes to neurodegenerative Cbl-deficient central neuropathy.

In vivo hormonal induction of ornithine decarboxylase in rat kidney.

Single pharmacological doses of parathyroid hormone, calcitonin, vasopressin, d-aldosterone, or L-triiodothyronine produced a significant increase in the ornithine decarboxylase activity of rat kidney. The activity of kidney ornithine decarboxylase was also enhanced by other hormones, such as pentagastrin and serotonin, which, although they are not known to modify kidney physiology, are secreted by cells having close relationships to the calcitonin-secreting parafollicular cells. The induction of the enzyme was observed in hypophysectomized rats, with or without some other hormone-secreting glands remaining. However, the magnitude of the stimulation elicited by the hormones was somewhat diminished in animals still having the endocrine gland whose hormone was being tested. The maximal stimulation of kidney ornithine decarboxylase activity by parathyroid hormone, calcitonin, vasopressin, L-triiodothyronine, pentagastrin, and serotonin occurred at 4 h after the hormone injection. The enhancement in ornithine decarboxylase activity produced by d-aldosterone was maximal at 3 h after the injection of the hormone. The content of ornithine in the kidney was found to be virtually unchanged whatever the type of hormone treatment. No statistically significant increases in renal ornithine decarboxylase activity of hypophysectomized animals were observed after injection of melatonin or of vitamin D3. Since the stimulating hormones possess clearly different mechanisms of action, the role of cyclic AMP as a general mediator of ornithine decarboxylase induction is questioned.

Polyamines in mammalian ageing: an oncological problem, too? A review.

This review surveys the literature about changes in polyamine contents and levels of activity of the enzymes involved in the polyamine biosynthetic pathway in organs of ageing mammals. The literature about changes in the polyamine levels in physiological fluids in healthy ageing humans is also reviewed. Generally speaking, decreases in the levels of the main polyamines (noticeably putrescine and spermidine) are observed in different mammalian organs with ageing. The polyamine levels in serum and in urine of healthy human beings are also age-related, declining progressively with increasing age. Some major enzymes (i.e., ornithine decarboxylase (EC 4.1.1.17) and S-adenosyl-L-methionine decarboxylase (EC 4.1.1.50) involved in the polyamine biosynthetic pathway show similar trends. Hormonal induction of ornithine decarboxylase activity is strongly reduced in organs of aged animals, as it is in neoplastic organs. There is also some evidence for an age-related decrease in the level of ornithine decarboxylase and its inducibility in mammalian cells cultured in vitro. Some in vitro effects of spermidine and spermine on aged structures or systems are briefly summarized. There is no evidence yet that this generally reduced capacity of mammalian aged organs for polyamine biosynthesis is one of the factors responsible for the well known high incidence of some neoplasias in elderly humans. In view of the typical stimulatory effects of the tumour promoters on polyamine biosynthesis in target tissues and the effects of senescence on the same metabolic pathway, it can be excluded that the ageing process has a tumour promoting effect by itself. However, although the exact mechanism responsible for the increased occurrence of some tumors during mammalian senescence is still obscure, there are enough experimental data (both in humans and in animals) to indicate that the reduced polyamine biosynthetic capacity of aged mammals can account for the slower course of some tumors in elderly patients.

Polyamine biosynthetic decarboxylases in muscles of rats with different experimental myopathies.

The activities of the two polyamine biosynthetic decarboxylases (PBD), L-ornithine decarboxylase (ODC) and S-adenosyl-L-methionine decarboxylase (SAMD), have been measured in quadriceps femoris of rats killed at different times after the induction of calciphylaxis- or serotonin(5-HT)-induced myopathy. Decreases in both PBD levels were observed at early times after both myotoxic treatments. Subsequent progressive increases in both enzyme levels were observed to nearly control values by 4 days after 5-HT administration. In the 5-HT-treated rats, the effects on the myocardial PBD activities were different from those in skeletal muscle, with no effect on ODC but much on SAMD, when rats were killed shortly after 5-HT injection. These results demonstrate that the time-course of the changes in PBD activities in quadriceps femoris mirrors quite well the successive occurrence of degenerative and regenerative processes during the calciphylaxis-induced myopathy and the 5-HT-induced myopathy; it is 5-HT that is mainly responsible for the decreases in PBD levels observed in both experimental myopathies, since dihydrotachysterol alone was without any effect on PBD activity levels and 5-HT alone was effective; myocardial ODC reacts more slowly to 5-HT than quadriceps femoris ODC.

Polyneuropathy due to cobalamin deficiency in the rat.

In the present study, we investigated the peripheral nervous system (PNS) (both in terms of its ultrastructure and in terms of its function) of rats made cobalamin (Cbl)-deficient either through total gastrectomy or through prolonged feeding on a Cbl-deficient diet. In both these types of Cbl-deficient neuropathies we found: (a) ultrastructurally, intramyelin and endoneural edema, with no or minimal axonal damage in the PNS, in dorsal root ganglia, and the ventral and dorsal rootlets of the spinal cord; (b) electrophysiologically, a significant reduction in the nerve conduction velocity, consistent with that reported in (a); (c) morphometrically, a significant reduction in the density of myelinated fibers both in the sciatic nerve and in the peroneal nerve. All these pathological changes were reversed by chronic postoperative administration of Cbl into totally gastrectomized (TGX)-rats, hinting at the specificity of the damage itself in relation to the permanent Cbl-deficient status of the TGX-rats. No signs of segmental demyelination or remyelination were found. We also observed a turning of type I fibers into type II fibers in the soleus muscle of all our Cbl-deficient rats, however the Cbl deficiency had been induced. This muscular change was still present in TGX- and Cbl-treated rats, and it cannot be related to a malnutrition status, since it has been observed also in rats fed a Cbl-deficient diet. All these results demonstrate that Cbl deficiency strongly affects rat PNS within different parameters.

Subacute combined degeneration in totally gastrectomized rats: an ultrastructural study.

Severe permanent cobalamin (Cbl) deficiency was induced in rats either by total gastrectomy (TG) or through prolonged dietary Cbl deprivation. This paper deals with an ultrastructural investigation of different parts of the central nervous system (CNS) of rats made Cbl-deficient through one of these of two procedures. In both totally gastrectomized (TGX) rats and in rats chronically fed a Cbl-deficient diet, we observed intramyelin edema, with splitting of the lamellae, and interstitial edema affecting the white matter, mainly in the spinal cord (SC). These lesions were also present in the subcortical white matter, although to a lesser degree. In both TGX-rats and in rats chronically fed a Cbl-deficient diet the pyramidal tract and the optic nerve were completely spared. Vascular lesions were never observed. Intramyelin edema and interstitial edema of the white matter account for the patchy myelopathic spongy vacuolation, which is the histological hallmark of human subacute combined degeneration and has been previously seen in SC white matter of TGX-rats. Macro- and micro-glial cells in the white matter were activated, at least as seen ultrastructurally. Interestingly enough, there were activated glial cells even in the gray matter, in which neurons showed absolutely no alterations. Chronic subcutaneous Cbl administration of TGX-rats partially repaired the CNS damage. However, the amelioration produced by this treatment was greater when Cbl was given shortly after TG than when given three and four months after TG, i.e. when the lesions have already been formed.