Chronological changes in cerebral air embolism that occurred during continuous drainage of infected lung bullae

We present a 43-year-old man with cerebral air embolism that occurred during continuous drainage of infected lung bullae. This complication is extremely rare, and may have been caused by the passage of air into the pulmonary venous circulation through a bronchovenous fistula and/or damaged pulmonary vessels. Air densities were demonstrated along the right frontal gyri on a CT performed 1 h after the onset of embolism, then moved to the deep cortex after 2.5 h. Three days later, a cortical infarct accompanied with extensive white matter edema in the right frontal lobe was confirmed by MRI. These CT and MRI findings may indicate the passage of intravascular air from the superficial to the deep cortex and subsequent cerebral infarction.

Expression of myogenic regulatory factors during the development of mouse tongue striated muscle

While the role of myogenic regulatory factors (MRFs) in skeletal myogenesis has been well evaluated in limb and trunk muscles, very little is known about their role in tongue myogenesis. Here the expression of MRF mRNA in mouse tongue muscle was examined during development from embryonic day (E)11 to birth and compared them with that in hind-limb muscle. Desmin, muscle creatine kinase and troponin C mRNAs were used as markers for myoblast determination, myotubule formation and myofibre maturation, respectively. The mRNA quantities were determined by competitive reverse transcriptase-polymerase chain reaction. The expression profile of desmin mRNA indicated that myoblast determination occurred before E11 in both the tongue and hind-limb muscles; the profile of muscle creatine kinase and troponin C mRNAs indicated that myotubule formation and myofibre maturation began between E11 and 13 in both tongue and hind-limb muscles, but ended 2 days earlier in the tongue than in the hind limb. Expression of myoD and myogenin mRNAs began at E11, increased, and showed peak values earlier in the tongue muscle (E13) than in the hind-limb muscle (E15). Expression of MRF4 mRNA appeared earlier in the tongue (E13) than in the hind-limb muscle (E15) and increased in both muscles after that. These results suggest that myotubule formation and myofibre maturation in the tongue muscle progress faster than in the hind-limb muscle, a result of earlier expression of myoD, myogenin, and MRF4 in response to earlier functional demands such as suckling immediately after birth.

Three isoforms of mammalian hyaluronan synthases have distinct enzymatic properties

Three mammalian hyaluronan synthase genes, HAS1, HAS2, and HAS3, have recently been cloned. In this study, we characterized and compared the enzymatic properties of these three HAS proteins. Expression of any of these genes in COS-1 cells or rat 3Y1 fibroblasts yielded de novo formation of a hyaluronan coat. The pericellular coats formed by HAS1 transfectants were significantly smaller than those formed by HAS2 or HAS3 transfectants. Kinetic studies of these enzymes in the membrane fractions isolated from HAS transfectants demonstrated that HAS proteins are distinct from each other in enzyme stability, elongation rate of HA, and apparent K(m) values for the two substrates UDP-GlcNAc and UDP-GlcUA. Analysis of the size distributions of hyaluronan generated in vitro by the recombinant proteins demonstrated that HAS3 synthesized hyaluronan with a molecular mass of 1 x 10(5) to 1 x 10(6) Da, shorter than those synthesized by HAS1 and HAS2 which have molecular masses of 2 x 10(5) to approximately 2 x 10(6) Da. Furthermore, comparisons of hyaluronan secreted into the culture media by stable HAS transfectants showed that HAS1 and HAS3 generated hyaluronan with broad size distributions (molecular masses of 2 x 10(5) to approximately 2 x 10(6) Da), whereas HAS2 generated hyaluronan with a broad but extremely large size (average molecular mass of >2 x 10(6) Da). The occurrence of three HAS isoforms with such distinct enzymatic characteristics may provide the cells with flexibility in the control of hyaluronan biosynthesis and functions.

Adaptation of guinea-pig superficial masseter muscle to an increase in occlusal vertical dimension

To study the effect of increased occlusal vertical dimension on the fibre phenotypes of the superficial masseter muscle, the composition of myosin heavy-chains (MHC), myosin light-chains (MLC) and tropomyosin was investigated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and two-dimensional gel electrophoresis in conjunction with densitometric analysis in normal (control) and bite-opened (5.7 mm increase in the vertical dimension for 1 week) guinea-pigs. The superficial masseter contained two fast-type MHC isoforms, II-1 and II-2, in both the bite-opened and control groups; their relative content (mean+/-SD, n = 7) was 47.8+/-2.9% and 52.2+/-2.9%, in the bite-opened and 44.4+/-3.0% and 55.6+3.0% in control preparations, indicating no significant (p>0.05) changes in MHC composition in association with the bite opening. On the other hand, significant differences in MLC and tropomyosin composition were found between the two preparations. Although the MLC consisted of three components, LC1f, LC2f and LC3f, in both preparations, their relative content (mean+/-SD, n = 7) was 37.1+/-2.4%, 49.6+/-1.6% and 13.2+/-3.2%, respectively, in the bite-opened and 28.1+/-3.1%, 50.9+/-1.6% and 21.0+/-3.5% in the control preparations, indicating that the bite opening induced a significant (p < 0.0001) increase in the relative content of LC1f at the expense of that of LC3f. Although the tropomyosin consisted of two components, TM-alpha and TM-beta, in both preparations, their relative content (mean+/-SD, n = 7) was 91.8%+/-1.9% and 8.2+/-1.9%, respectively, in the bite-opened and 95.9+/-0.7% and 4.1+/-0.7% in the control preparations, showing a significant (p < 0.001) increase in the relative content of TM-beta in relation to the bite opening. These results indicate that in guinea-pigs an increase in occlusal vertical dimension for 1 week changes the composition of MLC and tropomyosin, with no significant change in MHC, in the masseter muscle. These changes might be required to meet altered functional demands.

The brainstem and thalamic lesions in dentatorubral-pallidoluysian atrophy: an MRI study

We studied the frequency and characteristics of brainstem and thalamic lesions in dentatorubral-pallidoluysian atrophy using MRI. Of 15 subjects diagnosed by DNA analysis, 13 had lesions in the pontine base, nine in the midbrain, and five in the thalamus. Lesions were correlated positively with the patient's age, but not with neurologic features or numbers of CAG repeats. Patients with Machado-Joseph disease or spinocerebellar ataxia 1 did not show these characteristic lesions.

Neuroimaging on delayed postanoxic encephalopathy with lesions localized in basal ganglia

A 59-year-old woman suffered from prolonged hypotension with myocardial infarction. Sixteen days after the episode, she showed bradykinesia, gait disturbance, and postural tremor. MRI revealed low signa intensities in the bilateral caudate nuclei and putamen on the T1-weighted image and high signal intensities on the T2-weighted image. PET with 18F-FDG revealed a severe decrease in glucose metabolism in bilateral basal ganglia. It is concluded that prolonged hypotension may induce localized delayed anoxic lesions in basal ganglia.

[Inflammatory sensory ataxic neuropathy presenting with alternating skew deviation on lateral gaze: a case report]

We report a 56-year-old female with chronic progressive sensory ataxic neuropathy presenting with alternating skew deviation on lateral gaze in the clinical course. She initially developed dysesthesias in the hands and feet asymmetrically, then gait disturbance developed over several months, and she was admitted to our hospital. Neurological examinations revealed profound deep sensory loss and mild superficial sensory disturbance with the absence of deep tendon reflexes, but muscular strength was completely preserved. EMG showed no evoked response of sensory nerve velocities and normal motor nerves. Sural nerve biopsy showed moderate demyelination with mild infiltration of inflammatory cells, and no vasculitis or onion bulb formation. CSF examination revealed elevation of cell counts and protein with marked intrathecal IgG synthesis and myelin basic protein, but finding of neurosyphillis. Serological examinations did not show any evidence of collagen disease, paraproteinemia, retrovirus infections or Lyme disease. Serum antiganglioside antibodies and anti-Hu antibody were negative. No evidence of malignancy was seen by radiological examinations and assays of tumor markers. In the weeks after admission, gait ataxia progressively worsened, and then she developed alternating skew deviation on lateral gaze, suggesting that the CNS was involved. No responsible lesion was detected on MRI. Corticosteroid administration improved not only the CSF findings, but also the neurologic symptoms, including the alternating skew deviation on lateral gaze. Although the disease entity was not identified, inflammatory demyelinating processes and immune-mediated mechanisms were considered to play important roles.

MRI findings of VIIth cranial nerve involvement in sarcoidosis

Right facial nerve palsy in a 58-year-old woman was due to sarcoidosis demonstrated by Gd-DTPA enhanced MRI. Abnormal enhancement of the right VIIth cranial nerve in the distal internal acoustic canal was seen on MRI. The enhancing lesion was smaller after 1 month of prednisolone 50 mg day-1. This is the first report on facial nerve involvement in neurosarcoidosis examined by Gd-DTPA enhanced MRI. The use of Gd-DTPA enhanced MRI with thin slicing, e.g. 3 mm slice thickness and 1 mm interslice gap, is effective in detecting small extramedullary lesions.

Mechanism of reduction of cortical blood flow in striatocapsular infarction: studies using [123I]iomazenil SPECT

Single photon emission computed tomography (SPECT) using [123I]iomazenil (radioligand of central-type benzodiazepine receptors) was employed to examine two patients with striatocapsular infarction. Patient 1 was a 61-year-old female with motor aphasia and hemiplegia on the right side. Magnetic resonance imaging (MRI) showed a lesion in the anterior limb of internal capsule and putamen on the left side. SPECT using 99mTc-HMPAO revealed a reduction of cerebral blood flow (CBF) in the frontoparietal region on the left side, but the delayed images in SPECT using [123I]iomazenil showed only a mild decrease of accumulation in the frontal lobe. Patient 2 was a 55-year-old male with hemiplegia on the left side. MRI showed a lesion localized in the basal ganglia and posterior limb of the internal capsule on the right side. SPECT using 99mTc-HMPAO revealed a reduction of CBF in the frontoparietal region on the right side and in the cerebellar hemisphere on the left side, but the delayed images in SPECT using [123I]iomazenil showed little decrease of accumulation in parietal lobe. The discrepancy between CBF and receptor images suggested that cortical hypoperfusion on striatocapsular infarction might reflect hypometabolism due to disconnection of the neuronal network between subcortical structure and cortex.

Effect of an increase in occlusal vertical dimension on the rate of cyclic actin-myosin interaction in guinea-pig masseter muscle

To study the effects of increased occlusal vertical dimension on these kinetics, the actin-filament sliding velocity on masseter myosins in an in vitro motility assay and the ATPase activity of masseter myosins from normal (control) and bite-opened (5.6 mm increase in the vertical dimension for 1 week) guinea-pigs were measured. In control myosin preparations, the average value (mean +/- SD, n = 5) for the actin-filament sliding velocity at 25 degrees C was 4.0 +/- 0.3 microns/sec. In bite-opened myosin preparations (n = 5), it was 3.4 +/- 0.3 microns/sec, a significant (p < 0.01) decrease. Myosin ATPase activity was also decreased significantly (p < 0.01) from 1.0 +/- 0.1 to 0.7 +/- 0.1 mumol Pi mg per min (mean +/- SD, n = 5) after the bite opening. These results strongly suggest that in guinea-pigs an increase in occlusal vertical dimension for 1 week decreases the turnover rate of actin-myosin interaction in the masseter through changes in the myosin isozyme. These changes may result in a slowing of the rate of detachment of myosin cross-bridges from actin filaments.

Chromosomal changes and progressive tumorigenesis of human bronchial epithelial cell lines

A simian virus 40 (SV40)-transformed human bronchial epithelial cell line, BEAS-2B, underwent progressive changes, including the development of tumorigenicity, during extended in vitro passaging. Karyotypic changes occurred in parallel with the phenotypic changes. For the first 12 passages following viral transformation, there were random karyotypic changes. Immortalization occurred between passages 12 and 21, corresponding with the accumulation of four characteristic abnormal chromosomes-m-1: add(15)(p11.1); m-2: der(8;9)(q10;q10); m-3: add(16)(p13); and m-4: mar4- and the loss of one homolog of chromosomes 8, 15, 16, 21, and 22. With further passaging (from 21 to 63), the acquisition of weak tumorigenicity was observed, accompanied by an increased frequency of cells containing all four common abnormal chromosomes, m-1 through m-4, and missing one normal homolog of chromosomes 8, 15, 16, and 22. Four tumor cell lines (B39-TL, B39-TR, B61-T4 and B61-T7) were established from tumors induced by the injection of these weakly tumorigenic BEAS-2B 39th- and 61st- passage cells into athymic nude mice. One of the cell lines, B39-TL, is significantly more tumorigenic than the others. It is notable that B39-TL showed two specific abnormal chromosomes, del(3p);der(3;15) (q10;q10) and m-6; der(21)t(3;21)(p14.2;p12) inducing deletion of a short arm of chromosome 3. Fluorescence in situ hybridization analysis with a probe for protein tyrosine phosphatase-gamma demonstrated loss of heterozygosity in the 3p14 region. The development of step-wise karyotypic changes in this in vitro carcinogenesis model parallels changes documented in several common human cancers.

Ganglioside alterations in the central and peripheral nervous systems of patients with Creutzfeldt-Jakob disease

We have examined the distribution and composition of gangliosides in central and peripheral nervous tissues from two patients with Creutzfeldt-Jakob disease (CJD). There were marked decreases in total ganglioside levels in CJD, with reductions in the cerebral cortex and cerebellum in the order of 20-30% and 50% of control values, respectively, though in spinal cord and sciatic nerve total gangliosides were not significantly altered. The percentage distribution of individual gangliosides was characterized by marked increases in GD3 and GD2, contrasting with severe decreases in GD1a, GD1b, GT1b and GQ1b; such changes were found throughout the patients' nervous tissues. An abnormal long-chain base composition was detected with the d20:1 component being decreased to less than 50% of control values, in the cerebrum, cerebellum and spinal cord. Changes in gangliosides occurred even in those tissues not severely affected neuropathologically. These ganglioside abnormalities are discussed in relationship to the pathogenesis of CJD.

[Analysis of mutations and heteroplasmy at mitochondrial DNA 11778 using non-RI single strand conformation polymorphisms in Leber's hereditary optic neuropathy]

Leber's hereditary optic neuropathy(LHON) is a maternally inherited mitochondrial disease of an acute or subacute bilateral loss of central vision. G to A substitutions at nucleotide position 11778 in mitochondrial DNA(mt DNA) have been identified in approximately 40% to 90% of patients. In this study, regions containing mt DNA 11778 mutations were analyzed by polymerase chain reaction(PCR), non-RI single strand conformation polymorphisms(SSCP) and direct sequencing. In 26 visually affected patients, mt DNA 11778 mutations were detected in 9 patients (36.4%). In one pedigree of a LHON patient(L-6), four unaffected family members had heteroplasmy of the 11778 mutation using non-RI SSCP. Ratios of the heteroplasmy between wild type and mutant mt DNAs can be detected in non-RI SSCP and accurately quantified by video densitometric analyzer. Two types of novel polymorphisms, 11696 G to A and 11719 A to G, in the mt DNA region were also found in this non-RI SSCP analysis. Non-RI SSCP is an efficient and accurate method for diagnosis of mt DNA 11778 mutations and quantifying heteroplasmy in patients with LHON and pedigrees.

[Nucleotide sequences at intron 6 and exon 7 junction of fibroblast growth factor receptor 2 and rapid mutational analysis in Apert syndrome]

Apert syndrome, acrocephalosyndactyly Type I, is an autosomal dominant craniosynostosis comprising acrocephaly, facial dysmorphism and severe syndactyly of the hands and feet. Missense mutations at codons 252 and 253 at 5'-end on exon 7 of fibroblast growth factor receptor (FGFR) 2 have been identified in a large number of patients with Apert syndrome. In this study, nucleotide sequences on the intron 6 were determined by vector ligation-PCR and direct sequencing. Five DNA samples from sporadic Apert syndrome were examined by non-RI SSCP and direct sequencing using a primer pair of intron 6 and exon 7. All cases of the syndrome showed abnormal banding pattern in the SSCP and missense mutations from Ser to Trp at codon 252 of the FGFR2 gene. The non-RI SSCP and direct sequencing of the FGFR2 exon 7 from genomic DNAs may be a useful and rapid molecular means for clinical diagnosis of Apert syndrome.

[Frequent missense mutations of fibroblast growth factor receptor (FGFR) gene families in craniofacial syndromes in Japanese patients]

Craniofacial syndromes, including Crouzon syndrome, Pfeiffer syndrome, Jackson-Weiss syndrome, Apert syndrome and achondroplasia, have been indicated that syndromes were associated with mutations of fibroblast growth factor receptor (FGFR) gene families. In this report, seven Japanese patients with craniofacial syndromes, three Crouzon syndromes and four achondroplasias, were analyzed on FGFR2 and FGFR3 genes by non RI-SSCP (single strand conformation polymorphisms) and direct sequencing. Missense mutations of the FGFR3 exon 10, at codon 380 in two sporadic cases and codon 375 in two familial cases, were detected in all cases of achondroplasia. Mutations of the FGFR2 were noted in Crouzon and Apert syndromes. One of three Crouzon syndromes has a missense mutation at codon 342 on exon 9. Highly frequent mutations were clustered within some localized regions of the FGFR genes in craniofacial syndromes. Alterations in these receptors due to missense mutations would thus appear closely involved in pathogenesis of craniofacial syndrome. The non RI-SSCP and direct sequencing of the FGFR genes, shown in this report, may be an appropriate approach for diagnosis of these syndromes with extensive clinical application.

Evidence for the covalent binding of SHAP, heavy chains of inter-alpha-trypsin inhibitor, to hyaluronan

We previously showed that serum-derived 85-kDa proteins (SHAPs, serum-derived hyaluronan associated proteins) are firmly bound to hyaluronan (HA) synthesized by cultured fibroblasts. SHAPs were then identified to be the heavy chains of inter-alpha-trypsin inhibitor (ITI) (Huang, L., Yoneda, M., and Kimata, K. (1993) J. Biol. Chem. 268, 26725-26730). In this study, the SHAP.HA complex was isolated from pathological synovial fluid from human arthritis patients. The SHAP.HA complex was digested with thermolysin, followed by CsCl gradient centrifugation. The HA-containing fragments thus obtained were further digested with chondroitinase AC II and subjected to TSK gel high performance liquid chromatography (HPLC). Peptide-HA disaccharide-containing fractions (the SHAP.HA binding regions) were further purified by reverse phase HPLC. Major peaks were analyzed by protein sequencing and mass spectrometry (electrospray ionization mass spectrometry and collision induced dissociation-MS/MS). By comparison with the reported C-terminal sequences of the human ITI family, the peptides were found to correspond to tetrapeptides derived from the C termini of heavy chains 1 of and 2 of inter-alpha-trypsin inhibitor (HC1 and HC2), and heavy chain 3 of pre-alpha-trypsin inhibitor (HC3), respectively, and a heptapeptide from HC1. Mass spectrometric analyses suggested that the C-terminal Asp of each heavy chain was esterified to the C6-hydroxyl group of an internal N-acetylglucosamine of HA chain. This report is the first demonstration to give evidence for the covalent binding of proteins to HA.

[Molecular diagnosis of a kindred with novel mutation of methylmalonyl-CoA mutase gene using non-RI SSCP]

A deficiency of methylmalonyl-CoA mutase (MCM) results in methylmalonic acidemia, which is inherited as an autosomal recessive disease and is characterized by accumulation of precursors and abnormal derivatives of methylmalonyl-CoA in body fluids. Abnormal splicing with 13 base pairs (bp) insertion at MCM exons 2 and 3 junction in MCM transcripts and a homozygous point mutation, g to a transition, on 5 bp downstream exon 2 were detected in a proband with methylmalonic acidemia. The parents in the kindred were heterozygous carriers of the g to a transition in MCM intron 2. Non-RI single strand conformation polymorphisms (SSCP) was conducted to devise for analysis of this MCM mutation. This non-RI SSCP is considered to be useful diagnostic means with high potential for extended clinical application.

Development of tumorigenicity in simian virus 40-immortalized human bronchial epithelial cell lines

Of five SV40-transformed clonal human bronchial epithelial cell lines previously shown to be nontumorigenic at early passages (R. R. Reddel et al., Cancer Res., 48: 1904-1909, 1988), two lines (BES-1A1 and BEAS-2B) from different donors have become weakly tumorigenic with further passaging. BES-1A1 passage 26 cells formed tumors in 3 of 9 athymic nude mice given s.c. injections, whereas BEAS-2B cells of > or = 32 passages formed highly cystic tumors at 8 of 58 injection sites after long latency periods [17 +/- 7 (SD) weeks]. These tumors took a total of 36 +/- 8 weeks to reach a diameter of 1.0 cm. Tumor cell lines were established from four BEAS-2B tumors, and these are resistant to the growth-inhibitory effects of serum, an inducer of squamous differentiation in BEAS-2B and normal bronchial epithelial cells. This finding supports the hypothesis that development of resistance to inducers of terminal squamous differentiation may be a step in the process of bronchial carcinogenesis. One of these tumor cell lines, B39-TL, is significantly more tumorigenic than the others and has a deletion from the short arm of chromosome 3 as has been described previously for some naturally occurring human bronchial carcinomas. Thus, from the clonally derived BEAS-2B cell line, cell populations with various degrees of tumorigenicity have developed. Analysis of the changes in these cells may yield insights into the multiple events involved in acquisition of the tumorigenic phenotype.

Portal vein thrombosis after splenectomy successfully treated by an enormous dosage of fibrinolytic agent in a short period: report of two cases

Portal vein thrombosis (PVT) after splenectomy in a patient with portal hypertension occurs with unusually high frequency. Recently, two patients with PVT following splenectomy were treated by fibrinolytic therapy with an enormous dosage of urokinase (UK) in a short period. PVT was quickly dissolved without side effects and the patients are now doing well without any recurrence of PVT. Therefore, when there is no evidence of bowel infarction, fibrinolytic therapy with an enormous dosage of UK over a short period is deemed to be both effective and essential as a conservative therapy for PVT.

Biochemical and cytogenetic studies of human lung cancers

In ongoing studies, we have tested resected lung cancers from 41 men and 49 women; of those with primary lung cancer, 46 patients are free of disease and 35 have died of cancer or have persistent disease. Measurements and studies were as follows: total cellular deoxyribonucleic acid content by image analysis (n = 77); total genomic deoxyribonucleic acid methylation state and banding patterns from probed Southern blots (n = 36); radioimmunoassay for motilin, bombesin, gastrin, vasoactive intestinal peptide, and cholecystokinin (n = 18); and cytogenetic analysis (n = 39). All lung cancers were hyperploid. Adenocarcinomas and epidermoid carcinomas were generally hexaploid to nearly septaploid; comparisons by stage and histologic features suggested potential prognostic correlations. There was general hypomethylation of deoxyribonucleic acid (p less than 0.001). Deoxyribonucleic acid digests from restriction endonuclease Hpa II, when probed with deoxyribonucleic acid homologous to KPN, showed banding patterns that separated histologically indistinguishable primary adenocarcinomas and metastatic adenocarcinomas from one another. Cancers studied with radioimmunoassay were all negative for polypeptide hormones. Five cancers grew adequately in vitro to permit study of 190 detailed karyotypes (20 to 50 per tumor). Chromosome modal numbers ranged from 49 to 109. There were from 4 to 20 clearly abnormal marker chromosomes per tumor; abnormality derived from chromosome 1 was prevalent. Ten of 19 tumors xenotransplanted to nude mice were carried through two to five transplant generations without a change in histologic patterns.

Novel antigen system for tracking epithelial cell migration in serum-free culture

We report here a unique system for tracking normal human urothelial cell migration in serum-free culture medium (HMRI-1). The key observation was that urothelial cells deposited red blood cell surface antigen on the culture dish in a remarkable pattern. Scrutiny of this pattern showed that each migrating cell left behind antigen imprints which formed parallel tracks the width of the cell. Hence the previous migratory history of the cells was instantly mapped by simply visualizing the antigen tracks deposited by the cells on the dish. Apart from providing a simple method for tracking urothelial cells, this observation has wider implications for mechanistic studies of epithelial cell movement in general. It also highlights the complicating effects associated with the addition of serum as a traditional culture supplement, since the inclusion of serum in the HMRI-1 medium abolished the above effect by inhibiting cell migration.

High performance liquid chromatographic separation of stereoisomeric bile acids as their UV-sensitive esters

High performance liquid chromatographic separation of a series of mono-, di- and trihydroxylated 5 beta-cholanic acids, which differ only in position and configuration of hydroxyl groups at positions C-3, C-7 and/or C-12, is reported. The C-24 free acids were derivatized to four different classes of UV-sensitive esters, i.e., p-bromophenacyl (BP), m-methoxyphenacyl (MP), 4-nitrophthalimidemethyl (NPM) and 9-anthrylmethyl (AM) esters, and chromatographed on two variants of C18 reversed-phase columns (Nova-Pak C18 and Zorbax ODS) with methanol-water systems as mobile phase. Separation efficiency and elution order of some isomeric pairs were influenced by both the structure of the C-24 ester groups and the nature of the columns used. Excellent chromatographic properties were found for those derivatives, particularly for the NPM esters.