Immunohistochemical study of hepatic angiomyolipoma

An immunohistochemical study was performed on nine hepatic angiomyolipomas (AML) found in eight patients. Histologically, the tumors were fundamentally composed of the three heterogeneous tissue components of blood vessels, smooth muscle cells (SMC), and fat cells, although the proportions and distributions were quite variable from tumor to tumor and from area to area in the same tumor. Additionally, cellular pleomorphism and atypia with occasional bizarre giant cells were found in the SMC component. This histologic feature might lead to a mistaken diagnosis of malignant neoplasm, and pathologists should therefore be aware of the broad histologic spectrum of hepatic AML. However, the immunostaining patterns were basically the same in all nine tumors. All tumor components were negative for epithelial membrane antigen (EMA) and for cytokeratin. The spindle-shaped SMC component of the tumor was occasionally positive for vimentin, desmin and alpha-smooth muscle actin, whereas epithelioid SMC were negative for all three. Both the epithelioid and spindle-shaped SMC were occasionally positive for S-100 and neuron-specific enolase. All types of SMC in the tumor, whether spindle, epithelioid, intermediate or pleomorphic SMC, were strongly positive for HMB-45, a melanoma-specific monoclonal antibody. Fat cells were occasionally positive for S-100. Endothelial cells were positive for factor VIII-associated antigen. Among hepatic tumors HMB-45 reactivity is, so far as we know, found exclusively in the SMC of AML, and the HMB-45 reactivity of a hepatic tumor is thus clearly an important piece of information in the diagnosis of AML.

Disparity between tidal and static volumes of immature lungs treated with reconstituted surfactants

We biologically assessed functions of several reconstituted surfactants with the same minimum surface tension (2-3 mN/m) as "complete" porcine pulmonary surfactant (natural surfactant) but with longer surface adsorption times. Administration of natural surfactant (adsorption time 0.29 s) into the lungs of surfactant-deficient immature rabbits brought a tidal volume of 16.1 +/- 4.4 (SD) ml/kg during mechanical ventilation with 40 breaths/min and 20 cmH2O insufflation pressure. In static pressure-volume recordings, these animals showed a lung volume of 62.4 +/- 9.7 ml/kg at 30 cmH2O airway pressure and maintained 55% of this volume when the pressure decreased to 5 cmH2O. With two reconstituted surfactants consisting of synthetic lipids or isolated lipids from porcine lungs plus surfactant-associated hydrophobic proteins (adsorption times 0.57 and 0.78 s, respectively), tidal volumes were < 38% of that with natural surfactant (P < 0.05), but static pressure-volume recordings were not different. Care is therefore needed in estimating the in vivo function of surfactant preparations from minimum surface tension or static pressure-volume measurements.

[Epidemiology of syringomyelia in Japan--the nationwide survey]

The nationwide epidemiological survey of syringomyelia was carried out in Japan by sending inquiries to neurologists, child neurologists, neurosurgeons and orthopedic surgeons for the period of 1991 and 1992. A total of 1,243 cases of syringomyelia were ascertained. Among them, 622 were men and 619 women, and the average age of onset was 28 years old. The classification by Barnett et al was used, presenting syringomyelia with Chiari malformation in 684 cases (51.2%), dysraphism in 47 (3.7%), post traumatic syringomyelia in 139 (11%), post-spinal arachnoiditis in 76 (6%), spinal cord tumor in 132 (10.5%) and others in 204. Its predominant clinical course was slowly progressive, but 202 cases (17.9%) showed rather stable course including spontaneous resolution in 29 cases. The main initial symptoms were numbness in 522 cases (42%), motor disturbance in 504 (40.5%), and pain in 296 (23.8%). Neurologic signs noted in the abnormality of deep tendon reflexes in 836 cases (67.3%), motor disturbance in 763 (60.4%) and positive pathological reflexes in 383 (30.1%). Sensory disturbance was found in 942 cases (75.8%) and the dissociated type were 559 out of them (59.3%). It is noteworthy that 982 out of 1,243 were documented by MRI and surgical operations such as foramen magnum decompression, syringo-subarachnoid shunt and others were performed in 829 cases. Syringobulbia was confirmed on MRI in 101 cases of syringomyelia in which spinal cord tumors were most frequently associated.

The murine lymphotoxin-beta receptor cDNA: isolation by the signal sequence trap and chromosomal mapping

To isolate novel molecules involved in intercellular signaling during mouse embryogenesis, we employed the signal sequence trap (SST) method, a newly developed strategy for cloning secreted proteins and type I membrane proteins. We constructed an SST cDNA library of mouse embryonic heart mRNA, screened 2000 clones, and acquired 1 positive clone that appeared to contain the signal sequence. Homology searches revealed that this clone encodes the mouse lymphotoxin-beta receptor (LT beta-R). The deduced amino acid sequence of the mouse LT beta-R was 66% identical to that of the human LT beta-R. Northern analysis of various organs in adult mice showed that expression levels of LT beta-R mRNA were strong in lung, liver, and kidney, moderate in heart and testis, but weak in brain, thymus, spleen, and lymph nodes. Since the mouse LT beta-R was already expressed in 7-day-postcoitus embryo, the LT beta/LT beta-R system might have some functions in early embryogenesis. We performed chromosomal mapping of the murine LT beta-R gene by linkage analysis with recombinant inbred mouse strains and found that its locus is very close to the tumor necrosis factor receptor 1 gene on chromosome 6.

CAG repeat expansion of Machado-Joseph disease in the Japanese: analysis of the repeat instability for parental transmission, and correlation with disease phenotype

Machado-Joseph disease (MJD) is caused by abnormal expansion of an unstable CAG repeat in a novel gene locating on chromosome 14q32.1. We analysed this CAG repeat polymorphism with 66 Japanese MJD patients. All the patients were selectively associated with abnormal expansion of the CAG repeat. Repeat length of the mutant allele did not overlap that of normal allele and closely correlated with not only age at onset but also with clinical phenotypes. CAG repeat size is apparently related to a wide variety of phenotypic presentations in MJD.

Structure and chromosomal localization of the human stromal cell-derived factor 1 (SDF1) gene

Stromal cell-derived factors 1 alpha and 1 beta are small cytokines belonging to the intercrine CXC subfamily and originally isolated from a murine bone-marrow stroma cell line by the signal sequence trap method. cDNA and genomic clones of human SDF1 alpha and SDF1 beta (SDF1A and SDF1B) were isolated and characterized. cDNAs of SDF1 alpha and SDF1 beta encode proteins of 89 and 93 amino acids, respectively. SDF1 alpha and SDF1 beta sequences are more than 92% identical to those of the human counterparts. The genomic structure of the SDF1 gene revealed that human SDF1 alpha and SDF1 beta are encoded by a single gene and arise by alternative splicing. SDF1 alpha and SDF1 beta are encoded by 3 and 4 exons, respectively. Ubiquitous expression of the SDF1 gene, except in blood cells, was consistent with the presence of the GC-rich sequence in the 5'-flanking region of the SDF1 gene, as is often the case in the "housekeeping" genes. Although genes encoding other members of the intercrine family are localized on chromosome 4q or 17q, the human SDF1 gene was mapped to chromosome 10q by fluorescence in situ hybridization. Strong evolutionary conservation and unique chromosomal localization of the SDF1 gene suggest that SDF1 alpha and SDF1 beta may have important functions distinct from those of other members of the intercrine family.

Spinocerebellar ataxia 1 (SCA1) in the Japanese in Hokkaido may derive from a single common ancestry

Spinocerebellar ataxia 1 (SCA1) is caused by expansion of an unstable CAG triplet repeat located on the short arm of chromosome 6. Precise mapping has shown a positional relationship to closely linked markers in the order of D6S109-D6S274-D6S288-SCA1-AM10GA-D6S89+ ++-EDN1 from centromere to telomere. The haplotype which cosegregated with the disease was determined in 12 Japanese pedigrees with SCA1. Although the alleles of the SCA1 haplotype varied from pedigree to pedigree, depending on the distance from the SCA1 locus, the affected and presymptomatic subjects carried the same alleles at D6S288 and D6S274. All the families with SCA1 had migrated from either Miyagi or Yamagata Prefectures, neighbouring areas in the Tohoku District, the northern part of Honshu which is the main island of Japan. It seems highly likely that SCA1 in the Japanese, at least those residing in Hokkaido, derives from a single common ancestry.

[An analysis of factors related to recurrence of superficial bladder cancer after transurethral resection]

A total of 205 patients with primary superficial bladder cancer (Ta, T1) followed more than 3 years were retrospectively analyzed for factors related to recurrence of tumors after transurethral resection. Patients age were 25 to 90 years old, average 61 years old, and there were 160 males and 45 females. Initial tumor grades were G0 in 4 patients, G1 in 48, G2 in 134 and G3 in 19. Seventy four patients had Ta tumor and 131 had T1. Initial treatments were transurethral resection (TUR) alone in 137 patients. TUR with intravesical chemotherapy in 64, with BCG therapy in 7 and others in 7. Factors examined included age, sex, chief complaint, shape, size, and number of tumors, tumor distribution (single area or multiple area), histological grade, stage and intravesical chemotherapy. Overall non-recurrent rate were 81.7% at 1 year, 60.7% at 3 year, 53. 8% at 5 year and 44.2% at 8 year. Five-year non-recurrent rate according tumor factors, showed significant difference regarding tumor size (< 1 cm or 1 cm <: P = 0.027), tumor number (single or multiple: P = 0.004), tumor distribution (single area or multiple area: p = 0.002), histological grade (< G1 or G2 < : p = 0.001) and stage (Ta or T1: p = 0001). However, there were no significant difference regarding factors of age, sex, chief complaint, tumor figure and presence or absence of intravesical chemotherapy. This results suggested that the tumor factors of size, number, tumor distribution, grade and stage were highly related to intravesical tumor recurrence of superficial bladder cancer.

Macrophage inflammatory protein-1 alpha in the cerebrospinal fluid of patients with multiple sclerosis and other inflammatory neurological diseases

The level of macrophage inflammatory protein-1 alpha (MIP-1 alpha), a newly discovered cytokine of chemokine family, was determined in cerebrospinal fluid (CSF) from 18 patients with multiple sclerosis (MS) and from control patients with other neurological disorders by an enzyme-linked immunosorbent assay (ELISA). The concentration of MIP-1 alpha in CSF was significantly elevated in MS in relapse (4.4 pg/ml) compared with non-inflammatory neurological disease control samples (0.3 pg/ml) (p < 0.0002). These concentrations in MS patients correlated well with leukocyte cell counts and protein content in CSF (r = 0.845, p < 0.0001; r = 0.853, p < 0.0001, respectively). In other inflammatory neurological disorders such as Behçet's disease and HTLV-1 associated myelopathy, significantly increased CSF levels of MIP-1 alpha were also observed. Chemokines are reported to play an important role in an early event of inflammation such as lymphocyte traffic. This report is the first study which confirmed the involvement of a chemokine in MS and other inflammatory neurological disorders.

Spinocerebellar ataxia 1 (SCA1) in the Japanese: analysis of CAG trinucleitide repeat expansion and instability of the repeat for paternal transmission

SCA1 is caused by expansion of an unstable CAG triplet repeat in a novel gene located on the short arm of chromosome 6. In 126 Japanese individuals from 12 pedigrees with SCA1, studies were done to determine if they carried this mutant gene. All the affected and pre-symptomatic individuals, determined by haplotype segregation analyses, carried an abnormally expanded allele with the range of 39-63 repeat units. This repeat size inversely correlated with the age at onset. However, contrary to reported results, size of the repeat did not correlate with gender of the transmitting parent. Therefore, the CAG triplet repeat instability on paternal transmission is not likely to be fundamental to SCA1.

Role of nitric oxide in non-adrenergic, non-cholinergic relaxation and modulation of excitatory neuroeffector transmission in the cat airway

1. The effects of nitrosocysteine (cys-NO), L-N omega-nitroarginine (L-NNA) and L-N omega-nitro-L-arginine methylester (L-NAME), oxyhaemoglobin and Methylene Blue were observed on the resting membrane potential, muscle tone and excitatory junction potentials (EJPs) of cat tracheal smooth muscle tissue. 2. Cys-NO (10(-9) to 10(-6) M) showed no effect on the resting membrane potential of smooth muscle cells of the cat trachea but it dose-dependently relaxed the tracheal tissue in the presence of 5-HT, atropine and guanethidine. 3. Electrical field stimulation (EFS) applied during contraction evoked by 5-HT in the presence of atropine and guanethidine evoked non-adrenergic, non-cholinergic (NANC) muscle relaxation. L-NNA (10(-4) M) and L-NAME (10(-4) M) completely suppressed the relaxation when single or short repetitive stimuli were applied, but suppression was incomplete with repetitive stimuli of 4 ms pulse duration applied at 20 Hz. A substantial part of the L-NNA- or L-NAME-insensitive relaxation was abolished by tetrodotoxin. 4. Cys-NO dose-dependently suppressed the EJPs without changing the resting membrane potential, and L-NNA, L-NAME, Methylene Blue and oxyhaemoglobin enhanced the amplitude of the EJP to 1.2-1.5 times the control value. 5. EJPs showed some summation when repetitive field stimulation was applied at 20 Hz. L-NNA or L-NAME enhanced the summation, and the mean slopes were increased from 0.61 +/- 0.22 to 2.0 +/- 0.3, or 1.9 +/- 0.2 mV per stimulus. Vasoactive intestinal polypeptide (VIP) antiserum and VIP antagonists further enhanced the summation in the presence of L-NNA. 6. These results indicate that NANC relaxation can be classified into two different components according to the threshold for activation, and nitric oxide is involved in one. The present results also suggest that endogenous or exogenous nitric oxide has a prejunctional action in inhibiting excitatory neuroeffector transmission in addition to a direct action on the smooth muscle cells, presumably by suppressing transmitter release from the vagus nerve.

[A study of tumor location and prognosis in renal pelvic and ureteral cancer]

A total of 245 patients with renal pelvic and ureteral cancer (transitional cell carcinoma) were retrospectively analysed for tumor location and prognosis. In 133 renal pelvic cancer patients, 34 patients (25.6%) had tumor in lower calyx, 33 patients (24.8%) in renal pelvis, 31 patient (23.3%) in upper calyx, 21 patients (15.8%) in whole renal pelvis and 7 patients (5.2%) in middle calyx, respectively. In 128 ureteral cancer patients, 60 patients (46.9%) had tumor in lower ureter, 27 patients (21.1%) in distal end of ureter, 26 patients (20.3%) in middle ureter, 12 patients (9.4%) in upper ureter and 3 patients (2.3%) in whole ureter. In combination of tumor location, 101 patients (41.2%) had tumor in only renal pelvis, 94 patients (38.4%) had in only ureter, 14 patients (5.7%) had in renal pelvis and ureter, 19 patients (7.8%) had in renal pelvis and bladder, 12 patients (4.9%) had in ureter and bladder, and 5 patients (2%) had in renal pelvis, ureter and bladder. Five year survival rate of renal pelvic cancer according to tumor location were 55.9% in upper calyx tumor, 60.8% in middle calyx tumor, 63.8% in lower calyx tumor, 60.2% in renal pelvic tumor and 63.8% in PUJ tumor, respectively. There were no significant difference between those 5 groups. Five years survival rate of ureteral cancer according to tumor location, 90% in upper ureteral tumor, 60.8% in middle ureteral tumor, 66.5% in lower ureteral tumor and 52.6% in tumor of distal end of ureter, respectively. Also in those 4 groups, there were no significant difference.(ABSTRACT TRUNCATED AT 250 WORDS)

Erdheim-Chester disease and slowly progressive cerebellar dysfunction

A 59 year old woman developed pronounced thirst, increased water intake, and increased urinary output followed by slowly progressive cerebellar symptoms. Brain MRI showed abnormal hyperintensity on T2 weighted studies in the region of both dentate nuclei without atrophy of the cerebellum or the brainstem. A 99mTC diphosphonate bone scan showed bone lesions in the distal parts of both femurs as well as distal and proximal parts of both tibias. The diagnosis of Erdheim-Chester disease was made by bone biopsy. This is the first case of Erdheim-Chester disease presenting as a slowly progressive cerebellar syndrome and diabetes insipidus, and also showing high signal lesions in deep cerebellar nuclei on MRI. Skeletal surveys are indicated for patients with otherwise unexplained slowly progressive cerebellar symptoms.

Cloning of cDNA and genomic DNA encoding fibroblast growth factor receptor-4 of Xenopus laevis

We have isolated and characterized the cDNA and genomic DNA encoding fibroblast growth factor receptor-4 of Xenopus laevis (XFGFR-4). The gene encompassing the total coding sequence spans about 10 kb, consists of 17 exons, and has an organization very similar to those of mammalian genes encoding FGFR-1 and -2, except that the XFGFR-4 gene does not contain an alternative exon for the third immunoglobulin-like domain nor an internal poly(A)-addition site. Thus, XFGFR-4 appears not to generate multiple forms of mRNA, as are identified for the mammalian FGFR-1, -2 and -3 genes. The amino-acid sequence of XFGFR-4 shows high homology to other vertebrate FGFR-4 species, but the similarity was significantly lower than in the cases of FGFR-1 and -2. Northern blot analysis showed the XFGFR-4 mRNA to occur throughout X. laevis early embryogenesis in a profile different from those of X. laevis FGFR-1 and -2.

Dementia with ALS features and diffuse Pick body-like inclusions (atypical Pick's disease?)

An autopsy case of dementia beginning with right hand muscle atrophy was reported. A 42-year-old woman with no family history of neurologic disease developed weakness of the right hand at age 30, and was diagnosed as having amyotrophic lateral sclerosis (ALS). The weakness and atrophy spread to the four extremities subsequently. At age 36, she could not walk without assistance. At age 38, she was first noted as having dementia with forced crying, and she also showed generalized muscle weakness and atrophy. She rapidly developed akinetic mutism, and died of respiratory failure at age 42, 12 years after the onset of the symptoms. Macroscopically, the brain showed fronto-temporal atrophy. Microscopic examination revealed numerous intracytoplasmic inclusions throughout the central nervous system (CNS) including anterior horn of the spinal cord. The inclusions were stained moderate to dark brown with silver stain. Electron microscopically, they consisted of fibrils covered along most of the length with granular and fuzzy materials. This case was thought to be difficult to categorize in any known neuro-degenerative diseases. We proposed the case to be "atypical Pick's disease" with ALS features. This case might be a new entity of neuro-degenerative disease.

Stimulation of circus movement by activin, bFGF and TGF-beta 2 in isolated animal cap cells of Xenopus laevis

Lobopodium is a hyaline cytoplasmic protrusion which rotates circumferencially around a cell. This movement is called circus movement, which is seen in dissociated cells of amphibian embryos. Relative abundance of the lobopodia-forming cells changes temporally and spatially within Xenopus embryos, reflecting stage-dependent difference of morphogenetic movements. The lobopodia-forming activity of dissociated animal cap cells was stimulated strongly by activin and bFGF, and weakly by TGF-beta 2. In addition, activin A was found to stimulate cellular attachment to the substratum when the cultivation lasted long. Thus, mesoderm-inducing growth factors stimulate lobopodia formation and cellular movements which may be necessary for gastrulation and neurulation in Xenopus early embryos.

Surfactant replacement reverse respiratory failure induced by intratracheal endotoxin in rats

OBJECTIVE

To evaluate the effect of surfactant replacement on respiratory failure induced by intratracheal injection of endotoxin in rats.

DESIGN

Prospective, randomized study.

SETTING

Laboratory at a large university.

SUBJECTS

Male Wistar rats, weighing 353 +/- 50 (SD) g.

INTERVENTIONS

Escherichia coli endotoxin (53 +/- 19 mg/kg) was injected into the trachea of 32 rats anesthetized with pentobarbital and mechanically ventilated with an FIO2 of 1.0. After PaO2 decreased to < 200 torr (< 26.7 kPa), the rats were assigned to three groups: a) a surfactant group (n = 16), given a modified natural surfactant suspension (100 mg/kg in 2.0 mL/kg of saline) by instillation into the airway; b) a saline control group (n = 8), given 2.0 mL/kg of saline; and c) an air control group (n = 8), given 2.0 mL/kg of air. An additional nine rats were ventilated in the same way but were not given endotoxin.

MEASUREMENTS AND MAIN RESULTS

Among the rats receiving endotoxin, the PaO2 of the saline and air control groups remained < 200 torr (< 26.7 kPa), while PaO2 of the surfactant group increased to 390 +/- 116 torr (52.0 +/- 15.5 kPa; p < .05 vs. the preassignment value) 15 mins after the assignment. These high levels were maintained throughout the experiment. Surfactant replacement also led to significant improvements in the PaCO2, the dynamic lung-thorax compliance, the pressure-volume recordings of the lung, and the chest roentgenograms. Histologic examination showed that the alveoli of the surfactant group were better aerated than the alveoli of the control groups. Findings in the rats not given endotoxin were almost normal, indicating that the influences of mechanical ventilation were negligible.

CONCLUSION

Surfactant replacement reversed respiratory failure induced by intratracheal injection of endotoxin in rats.

Binding capacity of serum IgA to jacalin in patients with IgA nephropathy using jacalin-coated microplates

Binding capacity of serum IgA to jacalin in 22 patients with IgA nephropathy, 14 patients with diffuse mesangial proliferative glomerulonephritis (non-IgA nephropathy) and 20 age-matched healthy adults was examined by enzyme-linked immunoassay (ELISA) using jacalin-coated microplates. In contrast to previous findings, the binding capacity of serum IgA to jacalin in patients with IgA nephropathy measured by ELISA using jacalin-coated microplates was significantly higher than that in healthy adults. The ratio of serum IgA levels measured by this method to those obtained by single radial immunodiffusion was significantly increased in patients with IgA nephropathy. It appeared that the capacity of serum IgA binding to jacalin was marked in these patients. It is concluded that the binding capacity of serum IgA to jacalin is not ubiquitously impaired in all patients with IgA nephropathy.

Molecular cloning of Xenopus HGF cDNA and its expression studies in Xenopus early embryogenesis

We isolated Xenopus HGF cDNA and examined its expression pattern in Xenopus early embryos and their dissected parts. Xenopus HGF consists of 710 amino acids and contains four kringle domains and serine protease-like structure just like mammalian HGF. Northern blot analysis showed that expression of Xenopus HGF mRNA starts at the late gastrula stage and its level increases during the period of later embryogenesis. Dissection experiments revealed that Xenopus HGF mRNA is expressed in the mesoderm region, especially in the ventral mesoderm, which for the most part gives rise to mesenchymal cells. Furthermore, HGF mRNA was expressed in response to activin A and basic FGF in blastula animal cap cells. Interestingly, a stronger activity was observed with bFGF than with activin and this finding corroborates the preferential expression of HGF mRNA in the ventral mesoderm. Based on these results, we conclude that the Xenopus homologue of HGF gene is transcribed during early embryogenesis preferentially in ventral mesodermal tissues, probably in response to the signals that induce ventral mesoderm.

Relationship between antisaccades and the clinical symptoms in Parkinson's disease

We studied voluntary control of saccadic eye movement in 32 parkinsonian patients using the antisaccade task (the subjects were instructed not to look at the target but to look in the opposite direction). Mean latencies and error rates in the antisaccade task were significantly increased in advanced parkinsonian patients. The latencies of the antisaccades correlated with the severity of bradykinesia as well as the results of the Wisconsin Card Sorting Test. Patients taking anticholinergics showed significantly higher error rates. These results suggest that disturbance in the initiation of voluntary saccades in advanced patients may be associated with frontal lobe dysfunction, while anticholinergics may affect the inhibitory control of reflexive saccades.

Endothelial cell heterogeneity in experimentally-induced rabbit atherosclerosis. Demonstration of multinucleated giant endothelial cells by scanning electron microscopy and cell culture

We investigated the aortic endothelial cells of cholesterol-fed rabbits, using scanning electron microscopy and a cell culture technique. Rabbits were given a 1% cholesterol diet intermittently for up to 40 weeks. In these animals, the area of endothelial cells was increased and the cells showed polymorphism in relation to the progression of atherosclerosis. In animals fed the cholesterol diet for 12, 28 and 40 weeks, the average area of the endothelial cells was 436 +/- 15, 762 +/- 153, and 836 +/- 165 microns2, respectively. In the cholesterol-fed 40-week group, in particular, giant endothelial cells, measuring more than 1200 microns2, accounted for 14% of the population. In animals fed a standard diet there was no significant difference in endothelial cell morphology between control 0-week and control 40-week groups; in both, the luminal surface of the thoracic aorta formed a homogeneous sheet covered by small rhomboidal endothelial cells, the area of most being less than 400 microns2. Primary cultured endothelial cells harvested from those control groups were mononuclear typical small cells with a centrally located nucleus; the proportion of binucleated cells was less than 2% and no multinucleated giant cells with three or more nuclei were detected. Endothelial cells from the cholesterol-fed groups, however, contained larger numbers of binucleated cells, with the number increasing in proportion to the duration of cholesterol feeding. The major distinguishing feature of the endothelial cells in the cholesterol-fed groups was the presence of multinucleated giant cells with three or more nuclei; these accounted for 2.3% and 3.3% of the total cell population in the cholesterol-fed 28- and 40-week groups, respectively. No bromodeoxyuridine uptake was found in the nuclei of the cultured multinucleated giant cells. Heterogeneity of endothelial cells, with the concomitant appearance of multinucleated giant cells, emerges with the progression of diet-induced atherosclerosis. The morphological alterations of endothelial cells observed in the present study intimately reflect changes in their function associated with the progression of atherosclerotic lesions.