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The effects of colchicine and vinblastine on memory in chicks.

Colchicine, injected bilaterally into the forebrain of day-old chicks at times before and after one-trial avoidance learning, produced transient amnesia for one to three hours after learning, that could not be accounted for as a perceptual or attentional defect. The amnesia was dose dependent and was produced only when injections occurred within a limited period before and after learning. No amnesia occurred when injections were given 120 min before or 60 min later than the learning trial, nor at times prior to the retrieval test. During the amnesic period, new learning could occur and be retrieved 15 min later. The amnesia could be overcome by retention-testing or by a new, related, learning experience before or up to 30 min after onset of amnesia. Control birds injected with saline or lumicolchicine, a biologically inactive derivative of colchicine, showed normal retention. Vinblastine sulphate, which also interrupts microtubular networks and hence axonal flow, had no amnesic properties. Colchicine injections had no effect on the levels of acetylcholinesterase, choline acetyltransferase, glutamic acid decarboxylase, and muscarinic acetylcholine receptors in the whole forebrain or in forebrain synaptosomes during the amnesic period. Nor did colchicine injections affect amino acid uptake and protein or glycoprotein synthesis before or during the amnesic period, although there was 10-20% inhibition of protein synthesis 5 h after injection. Thus over the amnesic period, there was no evidence of gross perturbation of brain function. Electron microscopy showed microtubules intact within 1 mm of the injection site 2.5 after injection. Oedema was found at this time in chicks injected with a high dose (100 micrograms) shown to disturb behaviour grossly, but not with a low dose (5 micrograms) which caused amnesia. Transient amnesia for one-trial avoidance learning is most probably caused by secondary effects of colchicine on nerve cell function. We suggest that the amnesic episode represents destruction of one of the stages of a multiple independent parallel process of memory consolidation.

Animals↗

Vasoactive intestinal peptide expression in enteric neurons is upregulated by both colchicine and axotomy.

Axotomy is known to induce changes in neuropeptide expression in several types of neurons. Colchicine blocks the axonal transport and may mimic axotomy. The effects of colchicine-treatment and axotomy (local nerve crush by clamping of the gut) on enteric neurons expressing vasoactive intestinal peptide, neuropeptide Y and nitric oxide synthase were studied in rat small intestine by immunocytochemistry and in situ hybridization. Colchicine treatment significantly increased the number of submucous and myenteric neurons expressing vasoactive intestinal peptide and its mRNA. In contrast, an increase in the number of neuropeptide Y or nitric oxide synthase expressing neurons could not be detected. Axotomy markedly increased the number of myenteric vasoactive intestinal peptide-immunoreactive neurons in the segment located orally to the lesion, but not in the segment anally to the lesion, whereas that of nitric oxide synthase and neuropeptide Y expressing neurons was not affected. Double immunostaining revealed that the myenteric neurons containing nitric oxide synthase were induced by colchicine and axotomy to express vasoactive intestinal peptide. The present data indicate that colchicine and axotomy may induce marked changes in the neuropeptide expression of enteric neurons.

Animals↗

Colchicine does not inhibit secretin-induced choleresis in rats exhibiting hyperplasia of bile ductules: evidence against a pivotal role of exocytic vesicle insertion.

Based on studies in the pig, secretin choleresis has been proposed to be initiated by colchicine-inhibitable, exocytic insertion into the basolateral cholangiocyte membrane of intracytoplasmatic vesicles containing a H+ ATPase. Formal proof of this hypothesis in the intact liver of other species, however, is lacking. The effect of the microtubule inhibitor colchicine on the ductular bile formation and HCO3- secretion induced by secretin was, therefore, explored in a secretin-responsive rat model characterized by marked hyperplasia of bile ductules. While colchicine pretreatment significantly decreased basal bile flow from 142.1 +/- 8.8 to 83.4 +/- 8.2 microliters.min-1.kg-1 (p < 0.001) and basal biliary erythritol clearance from 112.7 +/- 6.3 to 69.9 +/- 7.0 microliters.min-1.kg-1 (p < 0.05), it did not significantly affect basal biliary [HCO3-], nor basal biliary bile acid output. Moreover, colchicine did not alter the effects of secretin. Thus, the secretin-induced increments in bile flow, biliary [HCO3-] and biliary HCO3- output averaged 58.2 +/- 13.6 microliters.min-1.kg-1, 16.6 +/- 3.1 mM and 5.3 +/- 1.4 mumol.min-1.kg-1 in vehicle-pretreated controls and 78.4 +/- 12.0 microliters.min-1.kg-1, 16.1 +/- 2.7 mM and 5.1 +/- 0.5 mumol.min-1.kg-1 in colchicine-pretreated animals (all p values = n.s.), respectively. This suggests that, at least in the rat model used, microtubule-dependent mechanisms are involved in basal, bile acid independent canalicular, but not in secretin-induced ductular, bile formation. Inasmuch as microtubule-dependent mechanisms are required for vesicle movement, this argues strongly against an absolute requirement for exocytic vesicle insertion in the ductular choleresis induced by secretin.

Animals↗

Functional teratogens of the rat kidney. I. Colchicine, dinoseb, and methyl salicylate.

Substances known or suspected to cause subtle or transient anatomical alterations in renal development were administered prenatally or neonatally to rats in order to determine whether they are capable of altering renal functional development. Colchicine alters mitotic activity and cytoskeletal structure and is teratogenic in many species. Since the kidney of the newborn rat undergoes extensive cellular proliferation and nephron differentiation, it is possible that neonatal administration of colchicine may affect nephron development. Dinoseb and methyl salicylate have previously been reported to produce a high incidence of dilated renal pelvis in the term rat fetus. Colchicine was injected sc, at 75 micrograms/kg, to Postnatal Day (PD) 1 Sprague-Dawley rats. Dinoseb was administered ip to pregnant Sprague-Dawley rats on Gestation Days 10-12 at doses of 8 or 10.5 mg/kg/day, and methyl salicylate was administered ip at doses of 200, 250, or 300 mg/kg/day on Gestation Days 11-12. Renal function was examined in pups from immediately after birth through weaning. Maximal urine concentrating ability was measured after DDAVP (desmopressin acetate, a vasopressin analog) injection in suckling rats, and after 24 hr of water deprivation in weanlings. Proximal tubule transport was measured in renal cortical slices. Basal urinary parameters, including urine flow, osmolality, pH, and chloride content, were measured. Colchicine treatment had no effect on body weight or kidney weight. There was a significant decrease in maximal urine osmolality in PD 30 rats measured after 24 hr of water deprivation. The urine concentrating deficit detected in functionally mature PD 30 rats suggests that colchicine treatment during renal histogenesis causes a latent deficit in medullary function in the absence of any gross morphological effects. The 10.5 mg/kg/day dose of dinoseb caused a weight reduction in neonates which persisted after weaning. Urine volume after DDAVP challenge was increased over controls in both dose groups on PD 6, but maximal urine concentration was unaffected. On PD 14, maximal urine concentration after DDAVP injection was decreased in the 10.5 mg/kg/day group. By PD 30, urine concentrating ability was comparable to controls. Renal cortical slices from the 10.5 mg/kg/day dose group had an enhanced ability to accumulate organic anions on PD 3 and 31, but opposite effects were observed in the low-dose group. No other renal functional parameters were altered. Urine osmolality after DDAVP challenge was decreased over controls in the 250 mg/kg/day methyl salicylate group on PD 6, and urine volume was increased in this group after DDAVP injection on PD 14.(ABSTRACT TRUNCATED AT 400 WORDS)

2,4-Dinitrophenol↗

Colchicine reduces myelin thickness and axoplasm volume.

A Silastic cuff containing either colchicine (1% w/v) or no colchicine was placed around the lingual disorder tympani nerve of the Mongolian gerbil. After 3 days of exposure to colchicine, the mean period of the myelin sheaths was 23% less than the period observed in nerves treated with cuffs lacking colchicine, while the average number of lamellae was unaltered. At the same time colchicine reduced the volume of axoplasm by an average of 19%, an effect which was independent of fiber diameter.

Animals↗

Colchicine increases hepatic alkaline phosphatase activity.

In vivo administration of colchicine increases the activity of alkaline phosphatase significantly in the livers of rats. Prior treatment with cycloheximide prevented the induction of the enzyme by colchicine suggesting that de novo protein synthesis was essential for the effect of colchicine on alkaline phosphatase activity. Bilateral adrenalectomy did not affect the response of alkaline phosphatase following the administration of colchicine. This indicates that the rise in the level of alkaline phosphatase in liver caused by colchicine is not secondary to the release of glucocorticoids.

Adrenalectomy↗

Neurotoxic effects of colchicine: differential susceptibility of CNS neuronal populations.

Colchicine injected into the dentate gyrus of the hippocampus in adult rats preferentially destroys dentate granule cells. In the present study, we examine the light- and electron-microscopic correlates of the degeneration and evaluate whether the selectivity is preserved across the range of doses between 0.18 and 25 micrograms. Colchicine in a similar dose range was also injected into the cerebellum, olfactory bulb, striatum and cerebral cortex to examine local and regional differences in susceptibility to colchicine. The morphological changes accompanying degeneration in the dentate gyrus include fragmentation of the granule cell layer, appearance of small dark staining bodies in the cell layer, massive microglial invasion and profound disruption of granule cell axons and dendrites. Electron-microscopic observations suggest that the small dark bodies are probably condensed nuclei. The preferential vulnerability of dentate granule cells following intrahippocampal injection was observed at all doses. At doses between 0.18 and 2.5 micrograms there was little evidence of damage to neurons other than dentate granule cells. At the highest dose tested (25 micrograms) some pyramidal cells of regio superior near the injection site were destroyed, while granule cell destruction extended several mm from the injection site. Injection of 0.5-25 micrograms into the cerebellum resulted in the destruction of both granule cells and Purkinje cells, while cells which appeared to be neurons in the molecular layer were less affected. Following injection of 0.5 microgram into the olfactory bulb, granule cells were extensively destroyed and there appeared to be some loss of mitral cells and an overall shrinkage of the injected bulb. Neuronal destruction in the striatum was observed with colchicine injections ranging from 2.5 to 25 micrograms, but at a given dose, the destruction was less extensive than for any other region tested except cerebral cortex. A possible application of this method and the implications of these results for other investigators using colchicine in the brain are discussed.

Animals↗

Selective axonal transport in a single cholinergic axon of Aplysia--role of colchicine-resistant microtubules.

Substance-specific selective axonal transport was examined in a single axon by injecting [3H]leucine and [14C]acetylcholine simultaneously into the cell body of a giant cholinergic neuron (R2) in the abdominal ganglion of Aplysia kurodai. The ganglion and attached nerves were cultured for several hours after the injection and the migration of radioactive substances along the axons of the injected neuron was examined. The substances examined were 3H labeled membrane proteins and soluble proteins synthesized in the cell body, 14C labeled bound acetylcholine formed in the cell, injected [3H]leucine and soluble [14C]acetylcholine. Membrane proteins and bound acetylcholine (plus a part of soluble acetylcholine) moved along the axon somatofugally at maximum velocities of 2.4 and 1.7 mm/h, respectively, at 25 degrees C. Soluble proteins, free leucine and most of the soluble acetylcholine did not move by fast axonal transport but diffused inside the axon of the neuron R2 at rates predicted from their expected diffusion constants in the axoplasm [Koike H. and Nagata Y. (1979) J. Physiol. 295, 397-417]. The diffusion kinetics of these substances were analysed and used for determination of true axon length, and to separate axonal transport components from diffusing components. An antimitotic drug, colchicine, selectively suppressed the axonal transport of membrane proteins but not of acetylcholine at 1-5 mM concentration, though it finally blocked the axonal transport of acetylcholine at 20 mM. When 1-5 mM colchicine was separately perfused only to the distal axon of the neuron R2, the migration of membrane proteins was stopped just proximal to the colchicine perfusion zone but acetylcholine migration was not disturbed by the drug. The moving component of acetylcholine was recovered by sucrose density centrifugation from a compartment previously reported as that of vesicular acetylcholine. As a possible mechanism of this selective axonal transport, it is proposed that there are two groups of microtubules: a colchicine-sensitive group of microtubules which may transport membrane proteins, and a colchicine-resistant group which may preferentially transport the transmitter substance acetylcholine at a slower rate.

Acetylcholine↗

Reversible colchicine-induced disruption of amygdaloid function in sodium appetite.

Bilateral injections of the antimitotic drug colchicine into the medial amygdaloid nuclei resulted in a dissociation of the normally concurrent sodium appetite and water thirst in rats following formalin-induced hypovolemia and hyponatremia. While control rats drank the normally aversive sodium solution as well as water after formalin injection, colchicine-treated animals failed to ingest the sodium solution but did consume the expected amount of water in order to compensate for hypovolemia. Sodium consumption, but not water consumption, remained significantly depressed in the colchicine-treated rats when they were challenged again with formalin 11 days but not 20 days after amygdaloid injections. The latter result suggested complete recovery from the colchicine-induced amygdaloid dysfunction. This study indicates that colchicine may serve as a potentially useful technique for producing reversible lesions of known duration for the assessment of brain-behavior relationships.

Afferent Pathways↗

Effects of colchicine on hexokinase activity in the paraventricular and supraoptic nuclei of spontaneously hypertensive and normotensive rats.

The effects of intracerebroventricular (ICV) colchicine (70 micrograms per rat) on systolic pressures and levels of hexokinase activity in the hypothalamic paraventricular (PVH) and supraoptic (SON) nuclei were investigated in adult normotensive and spontaneously hypertensive rats (SHR). One day after colchicine injection, systolic pressures had dropped significantly in Sprague-Dawley (SD) rats, Wistar-Kyoto (WKY) rats, and SHR; the largest decrease was seen in SHR. Postinjection pressures in SHR were within the normotensive range. No further decreases were observed two days after injections. Quantitative analysis of hexokinase activity in control animals verified that the parvo- and magnocellular PVH (but not SON) of SHR contained significantly lower levels of hexokinase than in WKY or SD rats. Two days after colchicine injection, hexokinase activities in pPVH and mPVH were similar in all three strains. Activity had decreased significantly in SD and WKY rats. In SHR, no differences between control and postinjection values were found. Hexokinase activity in SON was significantly decreased to the same extent in all strains. As metabolic activity in the pPVH, mPVH, and SON decreased after colchicine injection in normotensive rats whereas no such decreases occurred in the pPVH and mPVH of SHR, the findings suggest that colchicine may have differential effects on the metabolic activity of specific cell groups in brain depending on the physiological state of the animal.

Animals↗

Demonstration of peptidergic afferents to the bed nucleus of the stria terminalis using local injections of colchicine. A combined immunohistochemical and retrograde tracing study.

In the present study, we demonstrate the existence of numerous peptidergic afferents to the bed nucleus of the stria terminalis (BNST) using the retrograde transport of gold-labeled wheat germ agglutinin-apo-peroxidase (G-WGA-HRP) combined with the indirect immunoperoxidase method after intraparenchymatous injections of colchicine. At first, we show that local injections of colchicine alone into the BNST are able to induce the retrograde accumulation of peptides until the nerve cell bodies of origin, probably because of the blockade of axonal transport in nerve terminal arborizations innervating this nucleus. The actual existence of putative peptidergic afferents to the BNST indicated by the local injections of colchicine was established using: a) the retrograde transport of G-WGA-HRP from the BNST combined with immunocytochemistry after administration of colchicine at the same place, b) the anterograde "transport" of the fluorescent tracer DiI from selected nuclei of the forebrain. We demonstrate that the neurons immunoreactive for enkephalins, neurotensin, or substance P that innervate the BNST are localized mainly in the central amygdaloid nucleus, the paraventricular thalamic nucleus, and the ventromedial hypothalamic nucleus ipsilateral to the injection, as well as bilaterally in the magnocellular paraventricular and perifornical regions of the hypothalamus. From these results it may be concluded that intracerebral injections of colchicine constitute a powerful tool to search for multiple peptidergic afferents to a given brain nucleus using only immunohistochemistry. The existence of these pathways, however, must be verified by other neuroanatomical methods because of the problem of nerve fibers of passage.

Animals↗

Effects of intranigral injections of colchicine on the expression of some neuropeptides in the rat forebrain: an immunohistochemical and in situ hybridization study.

In the present study, we describe the neurochemical effects of intranigral injections of colchicine in the rat forebrain using immunohistochemistry and in situ hybridization. The observations on the injected side are compared to the contralateral one and to the sham-operated rats. We demonstrate that such injections are able to strongly enhance the immunoreactivity for Met-enkephalin (ME), substance P (SP) and neuropeptide Y (NPY) in numerous nerve cell bodies of the limbic system (injected side), whereas the levels of the corresponding mRNAs are differently modified according to the region examined. A clear correlation between the enhancement of the immunostaining for ME and SP and that of the preproenkephalin (PPA) and preprotachychinin gene transcripts was observed in neuronal perikarya of the medial amygdaloid nucleus (SP), of the dorsolateral hypothalamus (ME) and of the ventromedial hypothalamic nucleus (SP). These observations are interpreted as an induction--or increased expression--of neuropeptide genes in neuronal perikarya postsynaptic to nerve fibers originating in the midbrain and brain stem. In this case, colchicine is thought to block the electrophysiological activity of ascending nerve fibers (anterograde and postsynaptic effect). In the case where the enhancement of the immunoreactivity for the studied neuropeptides was associated with no change or a decreased expression of the corresponding genes in the same brain areas, colchicine may have blocked the axoplasmic transport of peptides in nerve fibers projecting to the midbrain and/or brain stem (6). This may result in a retrograde accumulation of peptides in the nerve cell bodies of origin and, eventually, in a negative feedback regulation of the corresponding encoding genes in these perikarya (retrograde and presynaptic effect of colchicine). The drastic behavioral effects of bilateral intranigral injections of colchicine, on ingestive behavior in particular, have been studied in a following paper.

Animals↗

Oxytocin synthesis and secretion from bovine corpora lutea exposed in vitro to cycloheximide and colchicine.

Two experiments were conducted to study the effects of cycloheximide and colchicine on prostaglandin F2 alpha (PGF2 alpha)-induced secretion and synthesis of oxytocin in bovine luteal tissue in vitro. Corpora lutea were collected from beef heifers on Day 8 of the estrous cycle. In Experiment 1, incorporation of [14C]-leucine into oxytocin synthesized and secreted by luteal slices after exposure to PGF2 alpha, cycloheximide and cycloheximide plus PGF2 alpha was examined. In Experiment 2, synthesis and secretion of oxytocin were evaluated in luteal slices incubated with colchicine and PGF2 alpha alone and in combination. Cycloheximide inhibited incorporation of labeled leucine into luteal proteins by more than 90% and no labeled oxytocin was detected in the media or tissue. Prostaglandin F2 alpha induced significant secretion of oxytocin that was not inhibited by cycloheximide. Tissue levels of oxytocin after incubation with cycloheximide and/or PGF2 alpha did not differ and were similar to those of the incubated control. Colchicine alone did not suppress oxytocin secretion and did not alter the ability of PGF2 alpha to induce significant secretion of this nonapeptide. Tissue concentrations of oxytocin after incubation with colchicine and/or PGF2 alpha did not differ. These studies indicate that secretion and replenishment of luteal oxytocin in vitro is not contingent upon de novo protein synthesis. Inability of colchicine to suppress oxytocin secretion and synthesis may have been due to the short duration of exposure of luteal tissue to the drug.

Animals↗

Computational and molecular modeling evaluation of the structural basis for tubulin polymerization inhibition by colchicine site agents.

The computer-automated structure evaluation programs MultiCASE and CASE were used to perform a quantitative structure-activity relationship study on tubulin polymerization inhibitors. A learning set of 536 chemicals (202 active. 27 marginal, and 307 inactive), built using IC50 values for inhibition of tubulin polymerization or mitosis from this and previous studies, was used for artificial intelligence self-teaching. The algorithms successfully predicted the activity of agents in the learning set with > 90% accuracy. Seventeen MultiCASE and twelve CASE (mostly included in the MultiCASE set) biophores (substructures significantly correlated with activity) were identified with a probability > 0.95. Here we present the biophores of podophyllotoxins, colchicinoids, and certain combretastatins, each examined for structure-activity relationships. For the podophyllotoxins and colchicinoids in the learning set, the correlations between observed and predicted potencies were > 0.85. The algorithms recognized the importance of several known site, electronic, and steric effects in the two classes. A predictive QSAR (R2 = 0.98) was developed for combretastain A-2 and dihydrocombretastatin analogues. The MultiCASE/CASE analyzes were used in combination with molecular models to study relative orientations of colchicine, podophyllotoxin, combretastatin A-4, and steganacin at the colchicine site. This resulted in a new hypothesis, consistent with extensive published experimental data, in which the C-ring and part of the B-ring of colchicine overlap with the A- and B-rings of podophyllotoxin. Consequently, the trimethoxyphenyl rings of colchicine and podophyllotoxin occupied different regions of space, each pointing out from a hydrophobic 'core' occupied by the overlapping biophores. The molecular model of the highly potent combretastatin A-4 could fit into the model binding site in at least three different ways. The developed QSARs were used to identify the potent microtubule stabilizer discodermolide. Its identification, in concert with recently reported findings, suggest potential overlap in the colchicine and paclitaxel binding sites on tubulin.

Antineoplastic Agents, Phytogenic↗

Colchicine-related death presenting as an unknown case of multiple organ failure.

A 45-year-old man presented to the emergency department (ED) with acute renal and hepatic failure as well as hypotension and metabolic acidosis. Despite aggressive intensive care, he had continued hypotension, leukocytosis, fever, renal and hepatic failure, and lactic acidosis. On hospital day 3, pancytopenia was noted. Bone marrow biopsy showed marked aplasia without a specific etiology being elucidated. He received granulocyte colony-stimulating factor and antibiotics, but died on hospital day 12 after a cardiac arrest. The patient repeatedly denied intentional drug ingestion. Due to his clinical course, the poison center recommended obtaining a colchicine level. The plasma colchicine level, 72 h after admission, was 6.1 ng/mL (GC/MS). This level exceeds acute levels reported in some cases of prior fatalities. This case is novel in that the patient's multiple organ dysfunction remained unexplained for several days before occult colchicine toxicity was implicated as the probable cause by the colchicine level. Also, there was a paucity of gastrointestinal symptoms on presentation, the opposite of what is expected in colchicine toxicity.

Bone Marrow Diseases↗

Colchicine and 2-methoxyestradiol Inhibit Human Angiogenesis.

BACKGROUND: Angiogenesis is a critical determinant of tumor growth and the development of metastases. Tubulin inhibitors have been shown to be effective inhibitors of angiogenesis. We hypothesized that colchicine, a well-know tubulin inhibitor and 2-methoxyestradiol (2 MeOH), a novel tubulin inhibitor, would limit the initiation of a human angiogenic response and would limit subsequent neovessel growth in a dose-dependent manner. METHODS: To test this hypothesis, we cultured full-thickness human placental vein discs from three placentas in a fibrin-thrombin clot model. Both colchicine and 2 MeOH were tested over a wide range of concentrations (10(-6) to 10(-12) M) to determine their effect on the percent of wells that initiated an angiogenic response (%I) and the subsequent growth (Angiogenic Index, 0-16 range) of vein-derived neovessels. RESULTS: Colchicine at doses of 10(-6) and 10(-8) M completely inhibited the angiogenic response (CI: 95%, P < 0.0001) but lower (10(-10) to 10(-12) M) doses did not significantly inhibit angiogenesis (P = NS). Effective in vitro colchicine levels far exceed achievable non-toxic human plasma levels. In contrast, 2-methoxyestradiol decreased initiation and angiogenic growth significantly at 10(-6) M (CI: 95%, P < 0.0001), but did not significantly decrease angiogenesis at doses of 10(-8), 10(-10), or 10(-12) M. In contrast to colchicine, human plasma levels of 10(-6) M 2 MeOH are achievable clinically with little or no associated toxicity. CONCLUSIONS: Effective in vitro drug levels of 2 MeOH can be achieved in vivo, suggesting that 2 MeOH may have a role in the clinical treatment of angiogenesis-dependent diseases.

2-Methoxyestradiol↗

Does colchicine have an antifibrotic effect on development of interstitial fibrosis in renal allografts of recipients with familial Mediterranean fever?

Colchicine, which has been reported to inhibit fibrosis, has been successfully used to treat fibrotic disorders, such as liver cirrhosis, scleroderma, and idiopathic pulmonary fibrosis. We hypothesized that besides its ability to prevent amyloid deposition, colchicine may prevent the development of interstitial fibrosis (IF) in amyloidosis patients who had undergone renal transplantation. We evaluated the influence of colchicine therapy on the development of IF in 25 patients with systemic amyloidosis secondary to familial Mediterranean fever (group 1). Twenty-five nonamyloidotic patients who did not receive colchicine therapy served as controls (group 2). The incidences of recurrence and development of IF in the first, second, and third years after transplantation were evaluated from follow-up allograft biopsies. Only four patients showed amyloid recurrence in their renal allografts. IF developed in 44% (11/25) of group 1 patients and 80% (20/25) of group 2 patients during the 36 months posttransplantation (P < .01). Development of IF in the first, second, and third years posttransplantation was significantly greater among group 2 recipients than group 1 recipients (P < .01). The overall 1-, 2-, and 3-year graft survival rates for group 1 recipients were 96%, 92%, and 80%, and those for group 2 recipients were 96%, 88%, and 60%, respectively. Our results support the thesis that colchicine therapy may help prevent the development of interstitial fibrosis in renal allografts.

Amyloidosis, Familial↗

Binding of colchicine to renal tubulin at 5 degrees C.

Previous reports in the literature state that the binding of colchicine to soluble tubulin is negligible at 0 - 4 degrees C as measured by non-equilibrium binding methods. In contrast, we have detected significant binding of colchicine to tubulin at 5 degrees C. Furthermore, for the first time equilibrium dialysis has been used to measure colchicine binding. The value of the dissociation constant was 1.8 microM at 5 degrees C, and the stoichiometry of colchicine binding at 5 degrees C equaled that at 37 degrees C. Dissociation at 5 degrees C of bound colchicine was negligible over a period of 23 h, and the estimated minimal half-time of dissociation was 150 h.

Animals↗