Hypervitaminosis A and matrix alterations in maxillary explants from 16-day rat embryos

Hypervitaminosis A in treated pregnant rats has been shown to interfere with normal palatal closure and fusion, as demonstrated by the presence of cleft palates in offspring. The observation that palatal shelves of excess vitamin A exposed fetuses are stunted and delayed in rotation suggests that vitamin A may inhibit a biochemical event crucial to the successful contact of the palatal shelves. Maxillary explants from 16 day Wistar rat embryos cultured in the presence or absence of 30 IU/ml retinyl palmitate were analyzed for DNA, glycosaminoglycan, and collagen synthesis. Maxillary explants cultured in vitamin A-containing medium showed an inhibition in DNA, GAG, and collagen synthesis in comparison to control explants. Excess vitamin A in the culture medium of maxillary explants also resulted in a reduction of intermolecular cross-links in collagen. The possible significance of the results in terms of cleft palate and normal secondary palate formation is discussed.     

Development of the residual cleft in the hard palate after velar repair in a 2-stage palatal repair regimen

Delayed closure of the hard palate is believed to improve maxillary growth and facial appearance in cleft lip and palate patients. However, the cleft opening in the hard palate after velar closure might impair speech development. The aim of this investigation was to study the development of the residual cleft in the hard palate after 2-stage palatal repair (TSPR) in children born with complete cleft lip and palate (bilateral [BCLP]; n = 7 or unilateral [UCLP]; n = 22) or isolated cleft palate (CP; n = 9). Moreover, we aimed to investigate whether any morphologic factors before surgery might predict development of the residual cleft. Dental casts obtained prior to velar repair (mean age 7 months) and postoperatively at 1 1/2, 3, 4, 5 and 7 years were analyzed with a Reflex Microscope regarding the width, length and area of the cleft in the hard palate. The palatal cleft varied in size both pre- and postoperatively in all 3 types of cleft patients. The width of the cleft in the UCLP subgroup showed a marked reduction immediately after velar repair, but then, on average, remained stable until final surgical closure of the hard palate. In the BCLP subgroup the initially rather narrow width of the clefts remained unchanged postoperatively. Clefts in the CP subgroup, especially in those with a complete cleft, remained large after veloplasty. In 4 of the UCLP and 2 of the BCLP patients, the cleft width increased gradually. In some other subjects, both in the UCLP and BCLP subgroups, the residual cleft closed functionally with time, but this development could not be foreseen.     

Dihydropyrimidine dehydrogenase but not thymidylate synthase expression is associated with resistance to 5-fluorouracil in colorectal cancer

BACKGROUND/AIMS: In planning adjuvant treatment of colorectal cancer, it is of critical importance to optimize the treatment by identifying subsets of patients that will respond or not to chemotherapy. Thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) are key enzymes involved in the biochemical functions of the antimetabolite 5-fluorouracil (5-FU). In searching for the factors determining the 5-FU sensitivity of colorectal cancer, TS and DPD were analyzed in relation to the inhibitory effect of 5-FU on cell proliferation in a series of human colorectal cancer cell lines. METHODOLOGY: TS and DPD protein expressions were quantified in 5 human colorectal cancer cell lines, using TS binding assay and Western blotting, respectively. Cellular growth inhibition was assessed by MTT assay after 48 hours of continuous exposure to 5-FU or cisplatin (CDDP). RESULTS: TS protein expression was detected in all but one of the cell lines studied and varied within a 17-fold range, while DPD protein expression was detectable in only one cell line (CaR1). CaR1, which expressed the highest level of DPD and no detectable TS, showed remarkable resistance to 5-FU. The other colorectal cancer cell lines with undetectable DPD expression were sensitive to 5-FU. There was no correlation between TS expression and 5-FU sensitivity. All of the cell lines studied showed similar sensitivity to CDDP. CONCLUSIONS: These data suggest that DPD, but not TS, expression predicts 5-FU sensitivity in colorectal cancer cell lines.     

Failure of carbon monoxide to induce myocardial infarction in cholesterol-fed cynomolgus monkeys (Macaca fascicularis)

The effect of prenatal administration of different doses of cortisone, corticosterone, dexamethasone, triamcinolone and prednisolone on the fetus and its palatal development was studied. All the glucocorticoids, except cortisone, produced cleft palate in the fetuses. Both the total frequency and morphologically different types of cleft palate were related to the dose of the teratogen. Triamcinolone appeared to be more potent than other glucocorticoid in inducing cleft palate. An association was noted between fetal growth inhibition, the dose of the teratogen and the frequency and type of cleft palate.     

Three-dimensional analysis of cleft palate topology in newborn infants with reference to the cranial skeleton

OBJECTIVE: To describe a method of determining the three-dimensional topology of the palatal crest relative to a reproducible anthropomorphic coordinate system in newborn infants with unilateral cleft palate. For this purpose, physical models of the maxilla and face were analyzed by computer morphometry. DESIGN: The study was limited to infants referred to the craniofacial center during the first 11 days after birth. SETTING: The study was performed at a craniofacial center servicing a large geographic area. PARTICIPANTS: The method was applied to 12 infants with unilateral cleft lip, alveolus, and palate (eight patients with left-side clefts and four with right-side clefts). MAIN OUTCOME MEASURES: The three-dimensional topology of the palatal crest referenced to an anthropometric coordinate system was the primary outcome measure. The anthropometric reference system is defined by the tragus points and the midpoint of a line connecting the endocanthia. RESULTS: The topology of the maxillary crests of the patients was characterized by considerable variability. The center of the premaxilla as defined by the attachment of the frenulum was frequently displaced by several millimeters from the midsagittal plane. The displacement was to the left in infants with right-side clefts and to the right in infants with left-side clefts. The premaxilla can be rotated by more than 30 degrees relative to the normal position. No significant retroposition of the minor segment as determined by the location of the tuber points was found. Several morphometric anomalies were found to be correlated linearly. CONCLUSIONS: We propose that the morphologic deviations are in part caused by the neuromotor activity of the tongue and of the interrupted M. orbicularis oris. The data can serve as the starting point for a longitudinal study of craniofacial development in children with cleft palate and for studies on the efficacy of different therapeutic approaches.     

The degree of masculine differentiation of obesities: a factor determining predisposition to diabetes, atherosclerosis, gout, and uric calculous disease. 1956

A study was undertaken to examine the effects of cyclophosphamide (CP) on growth and differentiation of palatal tissues. An in vivo/in vitro approach was designed to analyze (1) whether the damage caused by in vivo administration of CP in the developing palate can be altered in vitro, and (2) to determine the effects of CP on the synthesis of collagen and glycosaminoglycan (GAG), which are essential for proper palate development. In addition, effects of vitamin B1 and/or B6 on in vivo modulation of CP teratogenicity was evaluated. Pregnant hamsters were given 30 mg/kg CP or 1 ml saline on day 10 of gestation. Control and CP-treated embryonic palates were dissected on day 11 of gestation and incubated in vitro in the presence or absence of CP. In order to allow metabolic activation of CP in vitro, either a slice of hamster liver or microsomal S9 fraction of liver was added to the culture medium. To study collagen and GAG synthesis, palates were obtained between days 10 and 13 of gestation, and incubated in growth medium supplemented with [14C]proline or [3H]glucosamine, as appropriate. The rates of collagen and GAG synthesis were determined. The results showed that, in the controls, the presence of a liver slice or S9 fraction in the culture medium had no effects on in vitro closure of palate. In vivo CP exposed palates did not fuse in vitro. When drug was given in vitro, or both in vivo and in vitro, palatal closure did not occur. CP reduced synthesis of both collagen and GAG in the vertically developing palate. The drug-treated shelves reoriented only after the rates of collagen and GAG synthesis were restored to the levels comparable to the control counterparts. Co-administration of vitamin B1 and B6 did not interfere with the teratogenicity of CP. It was suggested that CP treatment affected DNA synthesis and injured growing cells, which in turn reduced the synthesis of GAG and collagen and affected the expansion of shelf volume to delay the reorientation of the palatal shelves. Furthermore, it appears that in vivo treatment with CP changes the programming of palatal tissues to prevent the fusion process in vivo, which could not be altered in vitro.     

Pathology of the palatal aponeurosis in cleft palate

OBJECTIVE: The palatal aponeurosis is a controversial structure, both in terms of its anatomy and its function. This article points out a pathologic finding in the cleft palate condition that has not been previously described. DESIGN AND METHOD: By means of surgical dissections, this study demonstrates in detail that the palatal aponeurosis exists even in cleft palates, but it is disrupted, malpositioned, and folded in two layers. PATIENTS: This dissection method has been performed on more than 150 patients with cleft of the hard and soft palate, with or without cleft of the lip and alveolus. At the time of operation, the children were between 6 and 8 months of age. RESULTS: It is possible to dissect the two layers of the palatal aponeurosis, to unfold the aponeurosis, and to form a tough tendinous plane. CONCLUSION: For a functional physiologic reconstruction of the cleft palate, it is necessary not only to reconstruct the levator veli palatini and palatopharyngeus muscle slings, but also to approximate and suture the fibers of the palatal aponeurosis to the corresponding fibers of the opposite side after unfolding them in a medio-dorso-cranial direction. In this manner, a continuous palatal aponeurosis can be created, which subsequently can serve as a transmitter of the muscle forces.     

Developmental and dysmorphogenic effects of glufosinate ammonium on mouse embryos in culture

The effects of glufosinate ammonium on embryonic development in mice were examined using whole embryo and micromass cultures of midbrain and limb bud cells. In day 8 embryos cultured for 48 hr, glufosinate caused significant overall embryonic growth retardation and increased embryolethality to 37.5% at 10 micrograms/ml (5.0 x 10(-5) M). All embryos in the treated groups exhibited specific morphological defects including hypoplasia of the prosencephalon (forebrain) (100%) and visceral arches (100%). In day 10 embryos cultured for 24 hr, glufosinate significantly reduced the crown-rump length and the number of somite pairs, and produced a high incidence of morphological defects (84.6%) at 10 micrograms/ml. These embryos were characterized by blister in the lateral head (100%), hypoplasia of prosencephalon (57.1%), and cleft lips (42.9%) at 20 micrograms/ml (10.0 x 10(-5) M). Histological examination of the treated embryos showed numerous cell death (pyknotic debris) present throughout the neuroepithelium in the brain vesicle and neural tube, but did not involve the underlying mesenchyme. In micromass culture, glufosinate inhibited the differentiation of midbrain cells in day 12 embryos with 50% inhibition occurring at 0.55 microgram/ml (2.8 x 10(-6) M). The ratios of 50% inhibition concentration for cell proliferation to cell differentiation in limb bud cells were 0.76 and 1.52 in day 11 and 12 embryos, respectively. These findings indicate that glufosinate ammonium is embryotoxic in vitro. In addition to causing growth retardation, glufosinate specifically affected the neuroepithelium of the brain vesicle and neural tube, leading to neuroepithelial cell death.     

Role of TGF-beta in RA-induced cleft palate in CD-1 mice

Retinoic acid (RA) plays an important role in embryogenesis, by regulating morphogenesis, cell proliferation, differentiation, and extracellular matrix production. RA exposure on gestational day (GD) 12 in CD-1 mice results in delayed palatal shelf elevation and subsequent clefts in the secondary palate. Given the dynamic and complex nature of palate development, it is not surprising that this system is susceptible to changes in retinoid levels. There is evidence that experimental manipulation of retinoid status during development alters normal transforming growth factor-beta (TGF-beta) status. To study the role of perturbation in TGF-beta levels in RA-induced cleft palate, gravid CD-1 mice were treated with 70 mg/kg RA on GD 12. We examined changes in TGF-beta proteins and the steady-state level of TGF-beta mRNA within the first 24 hr after exposure. The interactions between RA and TGF-beta s were very complex. RA differentially regulated the mRNA and protein levels of TGF-beta 1. Changes in mRNA steady-state levels were rapid and transient in nature, indicating a direct mediation by RA. Differential regulation was evident, because RA treatment resulted in an increase in TGF-beta 1 mRNA steady levels followed by a decrease in the intracellular and extracellular forms of TGF-beta 1 protein. Moreover, the patterns of localization and levels of TGF-beta 2 and TGF-beta 3 proteins were not dramatically affected, although there was an increase in TGF-beta 3 mRNA steady-state levels. The increases in mRNA steady-state levels for TGF-beta 2 and TGF-beta 3, as for TGF-beta 1, were rapid and transient in nature, again arguing for direct mediation by RA. These data provide evidence for interactions between RA and TGF-beta s, and indicate that RA is capable of differentially regulating TGF-beta isoforms through processes involving different stages of TGF-beta synthesis and secretion. Further, changes in TGF-beta isoforms were observed prior to changes in mesenchyme morphology and must be considered as mediators of RA's effects on mesenchyme development.     

The cellular interaction of 5-fluorouracil and cisplatin in a human colon carcinoma cell line

The combination of 5-fluorouracil (5-FU) and cisplatin (CDDP) has been shown to have synergistic cytotoxicity in human tumours, but the biochemical mechanism for this interaction remains unclear. Therefore, the aim of this study was to investigate the interaction of 5-FU and CDDP in a human colon carcinoma cell line, NCI H548. A 24 h exposure to 5-FU resulted in a 5-FU IC50 value of 24.2 +/- 4.5 microM, Dm 22.6 microM; exposure to CDDP for 2 h resulted in a IC50 value of 20.8 +/- 8.0 microM, Dm 21.9 microM. When cells were exposed simultaneously to 5-FU for 24 h and CDDP for the initial 2 h, or when cells were treated with CDDP for 2 h followed by various concentrations of 5-FU for 24 h, no greater than additive cytotoxicity was observed. In contrast, when cells were treated with 5-FU for 24 h prior to CDDP for 2 h, a greater than additive interaction was noted (5-FU IC50 1.2 +/- 0.6 microM, Dm 1.3 microM, CI 0.45). Thymidine 10 microM partially reversed the growth inhibitory effects of the 5-FU/ CDDP combination. Using both immunological and biochemical assays, no notable differences in the total amount of TS enzyme or the fraction of bound TS enzyme could be detected in the absence or presence of CDDP. No notable differences could be detected in intracellular reduced folate pools, FdUMP or FUTP pools, or 5-FU incorporation into RNA or DNA with the addition of CDDP to 5-FU. DNA fragmentation studies revealed that the combination of 5-FU followed by CDDP demonstrated a greater degree of single-stranded DNA fragments in parental (P = 0.024) and newly synthesised DNA (P = 0.025) compared with the administration of CDDP prior to 5-FU or either drug alone. The increase in smaller DNA fragment size was reversed with the addition of thymidine (10 microM). These findings suggest that the interaction of 5-FU and CDDP is associated with a greater degree of fragmentation of both nascent and parental DNA.     

Palatal thickening and facial form in Paranthropus: examination of alternative developmental models

Paranthropus is distinctive among hominoids in its possession of a greatly thickened hard palate. Although traditionally considered a structural adaptation to counter high-magnitude masticatory stress, alternative developmental models are equally viable. Three models of palatal thickening were evaluated in this study. A mechanical model interprets palatal thickening as a compensatory response to increased instability of the midpalatal suture effected by an anterior placement of the masseteric muscle mass. This model predicts that palatal thickness is correlated with the length of the palate posterior to the masseteric tubercle. Two non-mechanical models consider the thickness of the hard palate to be structurally related to and therefore correlated with either 1) the degree to which the premaxilla overlaps the hard palate in the subnasal region or 2) the height of the posterior facial skeleton. The correlation of craniofacial variables was assessed intraspecifically in ontogenetic series of great ape and human crania. Tests of correlation were performed for each comparison using both residuals calculated from reduced major axis regression of the variable of interest against a measure of cranial size and shape ratios. A significant correlation of palatal thickness with posterior facial height in Pan suggests that the unusually thick hard palate of Paranthropus is directly related to the increased posterior facial height characteristic of this taxon. Further evaluation suggests that extreme palatal thickening in these specimens occurred by virtue of their possession of a nasal septum morphology in which the vomer extends onto the superior and nasal surface of the premaxilla. Such a morphology would have constrained the palatal nasal lamina to maintain the approximate level of the premaxillary nasal lamina throughout the growth process thereby promoting palatal thickening.     

Current knowledge in cleft lip and palate treatment from an orthodontist's point of view

The aim of this review was to put new clinical research findings into proper perspectives relative to previously accepted knowledge on treatment of patients with cleft lip and palate. The first part of the paper deals with various aspects of infant orthopedic treatment, such as its influence on primary surgery, maxillary arch form and dimensions, feeding, psychological situation of the parents and speech development. Following parts analyze general maxillofacial growth outcome after surgery and also maxillofacial growth in relation to particular surgical procedures (palatal repair, periosteoplasty/gingivoplasty, bone grafting). The last part of the review discuss the effects of certain orthodontic/orthopedic treatment approaches as well as the role of dental implants in treatment of cleft lip and palate patients.     

Principles of dentofacial orthopedics

The differences in the response of patients to the same orthodontic treatment are, to a great extent, the result of variability in the direction and rate of craniofacial growth. Furthermore, there is currently little scientific evidence that the temporary improvement of skeletal relationships from orthopedic appliances will alter the craniofacial skeleton on a permanent basis. However, contemporary literature is beginning to show that certain appliances may be more effective than others at a specific point in the growth process. Timing of treatment in a patient is becoming of increased clinical importance. A review of the anatomy of palatal expansion indicates that expansion is much greater in the anterior portion of the palate, in both horizontal and vertical planes. Assessment of skeletal maturity for treatment timing and growth prediction is most commonly performed with the hand/wrist radiograph. A new method is presented which uses epiphyseal and diaphyseal widths and fusion of selected phalanges to determine the relative position of the individual on the pubertal growth curve. Skeletal maturity assessment is a traditional attempt to judge physiological development. The future of craniofacial growth assessment lies in the development of physiological measurements which are both replicable and valid and clinically feasible. The data from these studies provides information to allow better quantitative diagnosis and treatment as well as objective assessment of the treatment outcome.     

Bilaterally involved Tessier No. 4 cleft: case report

Craniofacial clefts are rare among facial anomalies, with an incidence of 1.5 to 5 per 100,000 births, and 1 per 100 cases of cleft lip and palate. The Tessier No. 4 oro-ocular cleft is one of the rarest, with 33 unilateral and bilateral clefts reported in the literature. Among the bilateral clefts only 3 of 9 involved Tessier No. 4 cleft bilaterally. We report a case of bilateral Tessier No. 4 craniofacial cleft and our approach to surgical correction.     

Deficient and delayed primary palatal fusion and mesenchymal bridge formation in cleft lip-liable strains of mice

During mammalian primary palate formation, the facial prominences enlarge around the nasal pit, fuse and then merge to give rise to the tissue of the upper lip and premaxillary region. The mechanisms involved in successful primary palate formation and how they are affected in the cleft lip genotype remain poorly understood. The purpose of this study was to compare morphometrically internal development and growth of the primary palate in five different strains of mice. Two of the strains, BALB/cByJ, and C57BL/6J, have normal primary palate development, and three of the strains, A/J, A/WySn, and CL/Fr, have stable frequencies of cleft lip associated with genotype. In the present study, frequencies of 4, 23, and 24%, respectively, were observed on day 13. For palatal growth analysis, embryos were collected on days 10 and 11, staged by number of tail somites (TS), and the heads were photographed and serially sectioned for measurement of primary palate components. The heights of the epithelial seam and the mesenchyme bridge between the facial prominences were measured on serial sections and areas of contact were calculated. The position or depth of the maxillary prominence was determined from the number of frontal sections from its tip to the rostral end of the nasal fin. Analysis of measurements showed that in cleft lip strains enlargement of the epithelial seam and replacement of epithelia by a mesenchymal bridge were both delayed relative to somite stages. Measurements from day 11 embryos with complete failure of contact were excluded from the growth analyses. The mesenchymal bridge formed at 12--13 TS in noncleft strains, 14 TS in the A/J strains with higher cleft lip frequency, and 15--17 TS in A/WySn and CL/Fr strains with higher cleft lip frequency. Forward growth of the maxillary prominence was highly correlated with the primary palate measurements and mesenchymal bridge formation in all strains. In both cleft and noncleft strains, the primitive choanae open at 18--20 TS and the medial nasal region narrows with advancing embryonic development. As a result, cleft lip-liable strains have a narrower window in development in which a robust mesenchymal bridge must form, thus increasing the liability to cleft lip.     

Plasma integrated concentration of growth hormone after recombinant human growth hormone injection. Implications for determining an optimal dose

The length of the cervical spine in a series of 206 adult males with cleft lip and/or palate and 50 normal controls was measured. The patients were divided into five subgroups according to the type and extent of the cleft. The shortening of the spine was most marked in bilateral cleft lip and palate patients (complete), less marked in unilateral cleft lip and palate patients, and was slight in isolated cleft palate patients. Complete isolated cleft palate and cleft lip was not associated with a shortening of the spine. A shortening of the cervical spine in less extensive types of isolated cleft palate was suggestive of the participation of the spine in their development, while in cleft lip and palate a simultaneous exposure to a teratogenic agent or any other developmental error during early stages of embryogenesis could explain the concomitant occurrence of spine anomalies. Patients with cleft lip and palate associated with a short spine also had a shorter mandibular ramus, which could be suggestive of simultaneous damage to both structures during morphogenesis. This relationship was not demonstrated in isolated cleft palate that developed in later stages of embryogenesis. In these cases a short spine itself could not have impaired the growth potential of the mandible, yet it could have mechanically induced the development of cleft palate. These observations are in agreement with the present state of knowledge on the development of orofacial clefts as shown in experimental animals.     

Alveolar bone grafting in unilateral complete cleft lip and palate patients

Autogenous bone graft of an alveolar cleft area has the following advantages: (1) assistance in the closure of buccoalveolar oronasal fistula; (2) provision of bony support for unerupted teeth and teeth adjacent to the cleft; (3) formation of a continuous alveolar ridge to facilitate orthodontic correction of malocclusion; (4) supporting the nostril floor and alar base to improve nasal aesthetics. It has been well accepted in most craniofacial centers as routine procedure in cleft lip and palate rehabilitation. A new surgical technique for alveolar bone grafting has been introduced to the Chang Gung Craniofacial Center since July 1991. It provided a good exposure of the alveolar cleft, primary closure of the fistula and adequate volume of bone graft. A review of 27 consecutive alveolar bone grafting procedures performed in unilateral cleft lip and palate patients from July 1991 to June 1992 was presented. Patients have been followed up for at least 6 months. The alveolar bone graft was evaluated clinically and radiologically at one week, six months and one year after the surgery. The preliminary results indicated that the new surgical technique produced less chance of recurrent fistula, good postoperative gingival height, and improvement of nasal aesthetics. Based on the results of this new study we strongly advocate the use of this new surgical technique.     

The immunomodulating action of cyclosporin A in vitro and in vivo on the lymphocytes of patients with alveolitis

The effect of various concentrations of ofloxacin, ciprofloxacin and lomefloxacin on the morphokinetic parameters of the cellular elements of the lung tissue of intact animals (mice, guinea pigs and dogs) was studied under the conditions of the tissue culture. It was shown that in a concentration of 100 micrograms/ml and the exposure time of 24 hours the drugs had no effect on the mobility and structure of the lung tissue cellular elements. When the drugs were used in a concentration of 100 micrograms/ml the mobility rate of the lymphocytes and macrophages proved to by markedly retarded by the end of the 24th hour. In a concentration of 1000 micrograms/ml the drugs killed the cell culture. There were detected no specific differences in the effect of the fluoroquinolones on the cellular elements of the lung tissue of the intact animals.     

High-dose diltiazem prevents migration and proliferation of vascular smooth muscle cells in various in-vitro models of human coronary restenosis

BACKGROUND: Restenosis after coronary angioplasty is considered to be caused mainly by increased migration and proliferation of smooth muscle cells (SMC). The concept of local, site-specific delivery of pharmacologic therapies has opened the door for new, high-dose drug regimes. METHODS AND RESULTS: SMC were isolated by enzymatic disaggregation with collagenase/elastase from human coronary plaque tissue of 29 patients (pSMC) and post mortem from the coronary media of 33 corpses (mSMC). Endothelial cells were isolated from human umbilical veins by enzymatic disaggregation with collagenase/dispase. By positive reaction with antibodies against smooth muscle alpha-actin and von Willebrand factor cells were identified as SMC or endothelial cells. In proliferation studies 5-150 micrograms/ml diltiazem was added to the culture media of pSMC, mSMC and endothelial cells. After 5 days there was a significant dose-dependent inhibition of cell proliferation (for pSMC with > 50 micrograms/ml, for mSMC with > 25 micrograms/ml, and for endothelial cells with > 5 micrograms/ml). In migration studies the effect of 5-150 micrograms/ml diltiazem on the velocity of migration of pSMC was investigated over a period of 48 h. Administration of diltiazem at concentrations of 100 and 150 micrograms/ml caused a significant inhibition of the migration of pSMC. The cytoskeletal components smooth muscle alpha-actin, vimentin, and alpha-tubulin of pSMC and the expression of von Willebrand factor of endothelial cells were investigated after an incubation period of 5 days with 50 and 150 micrograms/ml diltiazem. In the transfilter coculture model the effect of 50 micrograms/ml diltiazem on mSMC was investigated after mechanical injury of cocultured endothelial cells. Administration of diltiazem at a concentration of 50 micrograms/ml inhibited the development of a neointimal proliferate in the transfilter coculture model significantly (P < 0.001). CONCLUSIONS: A high dose of diltiazem inhibited the migratory and proliferative activities of coronary SMC significantly. In further experimental studies the effect of locally applied high doses of diltiazem on postangioplasty restenosis should be elucidated.