Three-dimensional reconstruction by scanning electron microscopy from serial epoxy resin semi-thin sections after ion-etching

Three-dimensional reconstruction was performed using scanning electron micrographs of serial semi-thin sections of Epon embedded specimens. Connective tissue in a rabbit ear chamber was fixed in glutaraldehyde and osmium tetroxide, and then embedded in Epon. One-microm-thick serial sections were cut with a diamond knife, mounted on glass slides and stained with toluidine blue. After observation with a light microscope, the sections were ion-etched with an ion-spatter coater. Following double staining with uranyl acetate and lead citrate, the consecutive sections were ion-coated with platinum. Each serial section was photographed with a scanning electron microscope. Profiles of a blood vessel and fibroblasts were digitized with a computer and computer reconstruction of the blood vessel was performed. Three-dimensional reconstructions showed that the newly formed blood vessel was a cylinder-like, bare endothelial tube with a rather smooth outer surface. Fibroblasts were situated around the endothelial tube. Several openings were found in the endothelial tube, suggesting the morphological feature of high permeability and fragility in newly formed blood vessels. The availability of three-dimensional reconstruction from scanning electron micrographs of serial semi-thin epoxy resin sections was discussed; structures of interest can be reconstructed (1) quickly and easily, (2) without skilful techniques, and (3) almost at the level of ultrastructure.

Otoacoustic emission in patients with neurological disorders who have auditory brainstem response abnormality

Otoacoustic emissions (OAEs) were evaluated in 51 ears of 30 patients with a severe auditory brainstem response (ABR) waveform abnormality. Thirteen ears showed no ABR to click sound of higher intensity than 100 dBSPL (group 1). Fourteen ears exhibited only wave V or a decreased amplitude pattern of ABR (group 2). Twenty-four ears showed a predominant wave I or no wave III pattern (group 3). Almost all the ears with absent ABR showed no OAE, which strongly suggested hearing loss of cochlear origin, although one patient with alternating hemiplegia of childhood exhibited definite OAEs and auditory reactions without ABR. One patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS) and her mother in group 2 had OAE abnormalities, which also suggested mild to severe hearing impairment. When OAEs are present, an accompanying ABR abnormality may be produced by brainstem dysfunction of the underlying disorder such as Pelizaeus-Merzbacher disease. There was a significant relationship (chi-square test P<0.001) between the positivity of the distortion product OAE response and the clinical auditory reactions in 24 patients, although their ABR abnormalities did not reflect hearing impairment directly. Careful examination of both audiometry and OAEs might be necessary for further assessment of the hearing function in pediatric patients with neurological disorders and specific auditory nerve disease.

Correlation of dietary food intakes and serum lipid fatty acids in urban senior citizens

Fatty acid compositions of serum lipids from elderly people (65 to 79 years old) in Koganei City of Tokyo were determined, and their correlation with dietary food intakes were examined. Cholesterol esters, triglycerides and lecithin revealed characteristic fatty acid profiles, respectively. Lecithin contained large amounts of eicosapentanoic and docosahexanoic acids (EPA and DHA) which belong to n-3 fatty acids as compared to other lipids. Sex differences in the fatty acid composition were found only in lecithin among serum lipids. Percentages of n-3 fatty acids were higher in males than in females, and were found to be positively correlated with the intake of fish. On the other hand, linoleic acid and n-6 fatty acids were shown to have positive correlations with beans. Arachidonic acid among n-6 had weak but significant correlations with eggs and milk.

In vitro cytotoxic effects of fludarabine (2-F-ara-A) in combination with commonly used antileukemic agents by isobologram analysis

Fludarabine phosphate (2-F-ara-AMP) is an adenine nucleoside analogue that shows significant activity against chronic lymphocytic leukemia and indolent lymphoma. We assessed the cytotoxic interaction produced by the combination of the active metabolite of fludarabine phosphate, fludarabine (9-beta-D-arabinofuranosyl-2-fluoroadenine, 2-F-ara-A), and some commonly used antileukemic agents against human hairy cell leukemia cell line JOK-1, human chronic lymphocytic leukemia cell line SKW-3, and adult T cell leukemia cell lines ED-40810 (-) and SALT-3. The leukemia cells were exposed simultaneously to 2-F-ara-A and to the other agents for 4 days. Cell growth inhibition was determined using MTT reduction assay. The isobologram method of Steel and Peckham was used to evaluate the cytotoxic interaction. 2-F-ara-A and cytarabine showed synergistic effects in SKW-3 cells, additive and synergistic effects in JOK-1 and SALT-3 cells, and additive effects in ED-40810(-) cells. 2-F-ara-A and doxorubicin showed additive effects in SKW-3, ED-40810(-) and SALT-3 cell lines, and additive and synergistic effects in JOK-1 cells. 2-F-ara-A showed additive effects with etoposide, 4-hydroperoxy-cyclophosphamide, and hydroxyurea in all four cell lines. 2-F-ara-A showed antagonistic effects with methotrexate and vincristine in all four cell lines. Our findings suggest that the simultaneous administration of fludarabine phosphate with cytarabine, doxorubicin, etoposide, cyclophosphamide, or hydroxyurea would be advantageous for cytotoxic effects. Among these agents, cytarabine may be the best agent for the combination with fludarabine phosphate. The simultaneous administration of fludarabine phosphate with methotrexate or vincristine would have little cytotoxic effect, and this combination may be inappropriate. These findings may be useful in clinical trials of combination chemotherapy with fludarabine phosphate and these agents.

A human B-cell CLL model established by transplantation of JOK-1 cells into SCID mice and an anti-leukemia efficacy of fludarabine phosphate

The present study was carried out to establish a human chronic lymphocytic leukemia (CLL) mouse model by transplantation of a JOK-1 human CLL cell line into SCID (severe combined immunodeficient) mice and to examine anti-leukemic effects of fludarabine phosphate, a prodrug of 9-beta-D-arabinofuranosyl-2-fluoroadenine (2F-ara-A). In vitro cytotoxic screening pattern of 2F-ara-A differed from those of other anticancer agents. Intraperitoneal inoculation with JOK-1 cells in SCID mice allowed the cells to infiltrate into a variety of organs including the liver and thymus, and resulted in the death of the mice with a median survival time of 29.5 days, associated with hepatomegaly, splenomegaly and enlarged lymph nodes. The ascitic cells expressing the human B-lymphocytic cell surface antigen CD19 actually grew after a latent period of 15 days. In this model, twice daily administration of fludarabine phosphate at a dose of 135 mg/kg for 5 days prolonged the survival time of the mice for considerably longer period than once-a-day treatment. Fludarabine phosphate in the doubled course of twice daily increased life span of 32.9%, which was in a similar range to that of doxorubicin. Thus, intraperitoneal inoculation of the human JOK-1 CLL cells into SCID mice seems to serve as an animal model potentially for human leukemia, suggesting that transplantation and subsequent infiltration processes of human CLL cells is useful measures to explore mechanistic aspects for drug-induced modulation of the tumor progression.

Developmental changes of distortion product and transient evoked otoacoustic emissions in different age groups

The developmental changes of distortion product otoacoustic emissions (DPOAEs) and transient evoked otoacoustic emissions (TEOAEs) were evaluated in 275 normal subjects aged from 1 month to 39 years. The DP-grams showed an M-shaped pattern with peaks at 1587 Hz and 5042 Hz for all age groups. In subjects younger than 3 years, low frequency DPOAEs did not rise above the noise floor. The DP levels at high frequency (5042 Hz) did not change much from infancy to young adulthood (12.9-16.5 dB SPL), however, those at low and middle frequency significantly decreased with age. Total echo power (TEP) of TEOAE was greatest in early infancy, decreased rapidly before 6-7 years old, and then decreased gradually (TEP = 16.6 - 1.9 X ln (age)). Wave reproducibility was constant across age. The frequency area peak power (FAPP) to middle and high frequency sounds changed little with age, however, FAPP at low frequency sounds dramatically increased with age. FAPP at 5000 Hz was relatively depressed levels at each age. The TEOAE value was more prominent at middle and low frequencies while DPOAE was predominant at high frequencies. These two measurements may reflect different functions of outer hair cells in the developing cochlea.

A new method for detecting and localizing cell markers endocytosed by fibroblasts in epoxy resin semi-thin sections using scanning electron microscopy combined with energy dispersive X-ray microanalysis after ion-etching

Cell marking is widely used to examine cell development and differentiation in developmental biology. We developed a new method for localizing cell markers in a semi-thin epoxy section with scanning electron microscopy. Cultured fibroblasts ingesting carbon particles were autologously transplanted into a rabbit transparent ear chamber, 6 mm in diameter and 100 microm in depth. Eight days after the transplantation, tissues in the chamber were fixed and embedded in epoxy resin. Semi-thin sections were cut and stained with toluidine blue. Fibroblasts in connective tissues which contained black spots were observed with a light microscope. These sections were subsequently ion-etched with an ion-coater and coated with platinum. The same fibroblasts were then visualized by secondary electron imaging using a scanning electron microscope. A nucleus with nuclear envelope, nuclear pores, a nucleolus and heterochromatin, mitochondria with cristae and rough endoplasmic reticulum were observed in the fibroblasts. The black spots in the fibroblasts were identified as bright bodies with the scanning electron microscope. The bright bodies were found to be a lump of tiny particles less than 100 nm in diameter. In order to analyse such particles with energy dispersive X-ray microanalysis, ion-etched sections were coated with carbon. X-ray energy spectrometry clearly demonstrated that these were carbon particles, which had been endocytosed by the fibroblast. This suggests that scanning electron microscopy combined with energy dispersive X-ray microanalysis is useful for detecting carbon particles in the cytoplasm at an ultrastructural level in semi-thin epoxy sections subsequent to ion etching and that this method may be applicable to other cell markers, such as gold particles to track cells in the field of cell development and cell differentiation.

The perfusion defect seen with SPECT in West syndrome is not correlated with seizure prognosis or developmental outcome

We used interictal single photon emission computed tomography (SPECT) on 40 patients with West syndrome to determine whether cortical perfusion abnormalities are closely related to the development of West syndrome and whether they are correlated with the long-term seizure prognosis or the developmental outcome. Localized cortical perfusion abnormalities were seen in 24 patients (60%), while 15 patients (38%) were classified as normal. The remaining patient showed hyperperfusion of the basal ganglia bilaterally. Of 24 patients with localized perfusion abnormalities, unifocal cortical hypoperfusion was present in 11, multifocal hypoperfusion in 10, multiple cortical hypo- and hyperperfusion in one, hyperperfusion of the bilateral frontal cortices and brain stem in one, and focal hyperperfusion in the residual frontal cortex in one. For statistical analysis, we focused on 26 patients (cryptogenic; 10, symptomatic; 16), who were followed for more than 2 years after the onset of tonic spasms (mean 5.0 years). The results showed that focal cortical perfusion abnormalities were not correlated with the long-term seizure prognosis, the developmental outcome, or the response to ACTH therapy. In agreement with previous reports, the results of interictal SPECT suggested that focal cortical lesions play an important role in the development of West syndrome. However, statistical analysis showed that the existence of cortical dysfunction as defined by SPECT did not predict the seizure prognosis or the developmental outcome.

Isolation and characterization of novel neutral glycolipids from Thermoplasma acidophilum

Several novel neutral glycolipids (GL-1a, GL-1b, GL-2a, GL-2b and GL-2c) were isolated from Thermoplasma acidophilum by high-performance liquid chromatography using phenylboronic acid-silica and preparative thin-layer chromatography. The tentative structures of these lipids were characterized by the combination of gas-liquid chromatography, the methylation procedure, and (1)H-NMR and FAB-mass spectrometries. The lipophilic portion of the neutral glycolipids was composed of a simple molecular species named caldarchaeol (dibiphytanyl-diglycerol tetraether). The sugar moieties of these glycolipids were composed of gulose and glucose which formed monosaccharide residues on one side or both sides of the core lipids. Gulose was attached to the terminal glycerol OH group of the core lipid with a beta-configuration and glucose being attached with an alpha-configuration. The proposed structure of GL-1a was gulosylcaldarchaeol and that of GL-1b was glucosylcaldarchaeol. The structures of GL-2a, GL-2b, and GL-2c were the analogs of the caldarchaeol derivatives attached by a variety of gulosyl residues or glucosyl residues on both sides of the terminal OH groups.

The origin of hypsarrhythmia and tonic spasms in West syndrome: evidence from a case of porencephaly and hydrocephalus with focal hypsarrhythmia

We report on a 3-year-old girl with West syndrome and with focal hypsarrhythmia. The left hemisphere of the patient was virtually completely defective and continuous hypsarrhythmia was only seen in the residual right frontal cortex, where an interictal single photon emission computed tomography (SPECT) showed hyperperfusion. Despite a focal epileptic pattern, the tonic spasms were quite symmetrical. In our patient, spasms might not require the sensorimotor cortex, but the brainstem containing the descending pathways that control spinal reflexes and other infratentorial structures seem to be essential for the occurrence of spasms. This is in accordance with the result of an ictal SPECT that showed hyperperfusion of the brainstem and cerebellum. These findings suggest that hypsarrhythmia originates from cortical lesions, while subcortical structures may be primarily responsible for the tonic spasms in this patient.

Heterogeneity of ictal SPECT findings in nine cases of West syndrome

We evaluated the ictal and interictal single photon emission computed tomography (SPECT) of 9 patients with West syndrome (WS). In this group, we noted two clear patterns of cortical hyperperfusion and subcortical hyperperfusion in the ictal SPECT. Both patterns were different from the previously documented ictal patterns for complex partial seizures (CPS) or secondarily generalized seizures. Our results suggest that the tonic spasms of WS do not always have a single neurophysiological basis; e.g., patients with hemihypsarrhythmia and focal hypsarrhythmia did not show ictal hyperperfusion of the lesion with hypsarrhythmia. These findings indicate that the origin of hypsarrhythmia as an EEG feature and the origin of tonic spasms may be different in such patients. In particular, hypsarrhythmia appears to originate from cortical lesions, whereas the subcortical structures may be primarily responsible for the tonic spasms. Our report is the first published study of ictal SPECT in patients with WS.

Mechanisms responsible for resistance of sublines derived from leukemia cell lines to an antitumor agent 9-beta-D-arabinofuranosyl-2-fluoroadenine

An agent 9-beta-D-arabinofuranosyl-2-fluoroadenine (2-F-Ara-A) is a main metabolite of fludarabine, a fluorinated purine analogue with antitumor activity in lymphoproliferative malignancies. In this study, the mechanism responsible for the resistance of cancer cells to fludarabine was examined using the 2-F-Ara-A-resistant sublines JOK-1/F-Ara-A and L1210/F-Ara-A from a human hairy leukemic cell line (JOK-1) and a mouse leukemic cell line (L1210) respectively, which were established by continuous treatment of the parental cell lines with 2-F-AraA. JOK-1/F-Ara-A and L1210/F-Ara-A cells were more than 55 and 29 times more resistant to 2-F-Ara-A than were their parent cell lines, and showed a high cross-resistance to 1-beta-D-arabinofuranosylcytosine but not to doxorubicin or vincristine. These resistant sublines intracellularly accumulated almost the same amount of 2-F-Ara-A as did their parent cell lines. However, the amount of 2-F-Ara-ATP, a cytotoxic metabolite of 2-F-Ara-A, decreased by 2.6% (JOK-1/F-Ara-A C3), 6% (L1210/F-Ara-A C1) and 3.7% (L1210/F-Ara-A C7) relative to the levels in the parent cell lines. Enzymatically, these resistant cells hardly activated deoxycytidine (dCyd) and 2-F-Ara-A. In addition, the abilities to phosphorylate deoxyadenosine and deoxyguanosine were also decreased in the resistant cells in comparison with the parent cells. These findings suggest that the deficiency in activity of dCyd kinase may contribute to the resistance of 2-F-Ara-A.

Gangliosides and sialylcholesterol as modulators of synaptic functions

Gangliosides were shown to enhance the release of acetylcholine from synaptosomes on stimulation. The influx of calcium ion into synaptosomes on membrane depolarization was increased by gangliosides. This was hypothesized to be an underlying mechanisms for the enhancement of acetylcholine release. Studies using calcium channel blockers revealed that four distinct types of voltage-dependent calcium channels occurred in cerebrocortical synapses, and that the N-type was primarily responsible for the evoked release of acetylcholine. An additional result suggests that gangliosides may act mainly on the N-type calcium channel. Cholinergic-specific gangliosides, Chol-1 alpha, were assumed to participate in the mechanism of high-affinity choline uptake. These two different actions of gangliosides were found to be mimicked by synthetic ganglioside analogs. Calcium influx was increased by alpha-sialylcholesterol, and choline uptake was accelerated by beta-sialylcholesterol. Gangliosides and sialylcholesterol having these apparently beneficial effects were shown to ameliorate decreased functions of synapses from aged brains.

Gangliosides enhance KCl-induced Ca2+ influx and acetylcholine release in brain synaptosomes

Effects of gangliosides GM1 and GQ1b on cholinergic synaptic functions were investigated using synaptosomes prepared from mouse brain cortices. Treatment of synaptosomes with GM1 and GQ1b increased high K(+)-evoked acetylcholine (ACh) release in a bell-shaped dose-dependent manner. The peaks of the effects were found to be at 1-5 microM for GM1 and 5-10 microM for GQ1b. ACh synthesis and the levels of ACh in synaptosomes were not affected by the ganglioside treatment. Both gangliosides enhanced depolarization-induced influx of calcium ions into synaptosomes. These results indicate that GM1 and GQ1b gangliosides increase evoked ACh release by modulating voltage-dependent calcium channels in the synaptic plasma membranes. The effect of GM1 on calcium ion influx remained after repetitive washings, but was almost completely abolished when the bound GM1 was removed by trypsin. This indicates that the fraction of GM1 which was tightly bound to, but not incorporated in synaptic plasma membranes, is responsible for activating the calcium channels.

Gangliosides expressed in human breast cancer

Breast tumors that were histopathologically diagnosed as invasive ductal carcinoma were examined in relation to their abnormal expression of gangliosides. Total ganglioside levels that were expressed as lipid-bound sialic acids were significantly higher in breast tumor tissues than in normal mammary tissues. Two kinds of unusual gangliosides were found to be expressed in many cases of breast tumors. One was a group of O-acetylated gangliosides, such as O-acetyl-GD3 and O-acetyl-GT3. They are known as fetal gangliosides, which appear in fetal brains. The other was an N-glycolylneuraminic acid-containing ganglioside, N-glycolyl-GM3, which had not been previously found in normal human tissues. The finding that unusual gangliosides are expressed in breast tumors may provide the basis for their immunological diagnosis and vaccine therapy.

MR findings in Tay-Sachs disease

OBJECTIVE

MR and CT findings in two patients of Tay-Sachs disease are reported.

MATERIALS AND METHODS

In two patients of Tay-Sachs disease, MR and CT studies were conducted in the early phase (11 and 10 months of age, respectively) and one was followed-up with MR in the late phase at the age of 5 years and 8 months. Six MR studies on this disease (including 3 other cases documented in the literature) were reviewed and correlated with the pathological phases of this disease.

RESULTS

MRI findings drastically changed during the phases of disease process in one case. In the early phase, T2-weighted MR images demonstrated hyperintensity in both basal ganglia and thalamus. MR images obtained in the late phase demonstrated markedly advanced brain atrophy and diffuse white matter lesions, which were hyperintense on the T2-weighted images. T1-weighted images exhibited hyperintensity in the basal ganglia, thalamus, and along the cortical layer of the cerebrum, which appeared to by hypointense on T2-weighted images.

CONCLUSION

MR was apparently superior to CT in clearly delineating lesions of this disease. These abnormal signal intensities in the late phase may reflect the pathological findings, marked accumulation of GM2 ganglioside in the basal ganglia and thalamus and along the cerebral gray matter.

A novel ganglioside, 9-O-acetyl GD1b, is recognized by serum antibodies in Guillain-Barré syndrome

A hitherto undescribed ganglioside was detected in a crude ganglioside fraction of bovine brain using an IgM M-protein binding to Gal beta 1, 3GalNAc residue. We purified and identified it as 9-O-acetyl GD1b based on results of alkali treatment that yielded GD1b and results of fast atom bombardment-mass and gas chromatography-mass spectrometries. 9-O-acetyl GD1b was also found to be present in human peripheral nerve tissue. The reactivities of the serum antibodies from patients with Guillain-Barré syndrome to 9-O-acetyl GD1b, GD1b, and GM1 were determined by ELISA and TLC immunostaining. Nineteen of 85 serum samples from Guillain-Barré syndrome patients had antibodies that bound to 9-O-acetyl GD1b: 14 of the positive samples also reacted with GM1 and GD1b, three reacted with GM1 but not with GD1b, one with GD1b but not with GM1, and one with neither GM1 nor GD1b. These results show that a subset of patients with Guillain-Barré syndrome had antibodies that react with 9-O-acetyl GD1b; therefore, this ganglioside can serve as a target antigen against the antibodies present in Guillain-Barré syndrome.

[Neonatal brain injury and evoked potentials]

Marked abnormalities in ABR at discharge from NICU can predict overall prognosis in patients with neonatal asphyxia. However, in patients with neonatal asphyxia as a single risk factor, the incidence of ABR abnormalities was low and ABR was not indicative of their long-term prognosis. Over the past 10 years, we encountered 13 patients with deterioration of ABR and progressive hearing impairment after discharge from NICU. All patients showed severe cardiorespiratory symptoms in the neonatal period. Nine of thirteen patients were diagnosed as persistent neonatal pulmonary hypertension. Multimodal evoked potential studies could predict life expectancy and functional state in patients with severe motor and intellectual impairment. These kind of neurophysiological test can show the patients' functional state at the time of the examination. Discrepancies in evoked potentials and clinical symptoms provide important information regarding the pathophysiology of the patients.

Characterization of four monosialo and a novel disialo Asn N-glycosides from the urine of a patient with aspartylglycosaminuria

We previously reported for the first time two Japanese patients with aspartylglycosaminuria (AGU). A novel disialo Asn N-glycoside (AG-5) has been isolated from the urine of one of the patients in addition to four known monosialo Asn N-glycosides (AG-1 to AG-4) by gel filtration and anion exchange chromatography in this study. Final purification of AG-5 was achieved by an electrochemical chromatographic method, high performance liquid chromatography with pulsed amperometric detector (HPLC-PAD). The yield of AG-5 was approximately 1 mg l-1 urine. The chemical structures of AG-1 to AG-5 were characterized by gas-liquid chromatography, a permethylation study, fast atom bombardment-mass spectrometry (FAB-MS), and nuclear magnetic resonance (NMR). Based on the structural analysis, AG-5 had the following novel structure: NeuAc alpha 2-->8NeuAc alpha 2-->3Gal beta 1-->4GlcNAc beta 1-->Asn.

Structural analysis of a novel triphosphonoglycosphingolipid from the egg of the sea hare, Aplysia kurodai

A novel phosphonoglycosphingolipid which contains three residues of 2-aminoethylphosphonate (2-AEP) was isolated from eggs of a sea gastropoid, Aplysia kurodai, and its structure was identified as follows. [see text] The major aliphatic components of ceramide were palmitic acid, stearic acid, 4-sphingenine, and 16-methyl-4-sphingenine. Antibodies which recognize 3-O-methylgalactose linked beta-glycosidically to phosphonoglycosphingolipids failed to react to the egg glycolipid. By comparing 1H-NMR spectra of native and HF-treated glycolipids, steric interactions of two residues of 2-AEP with ring protons of the glucose and the internal galactose were indicated.

The structure of the core polyol of the ether lipids from Sulfolobus acidocaldarius

The major ether-type lipid structures of Sulfolobus acidocaldarius (ATCC33909) were composed of caldarchaeol and calditoglycerocaldarchaeol. However, the characterization by nuclear magnetic resonance spectroscopy and mass spectrometry showed that the structure of calditol in calditoglycerocaldarchaeol is not nonitol, 2-(1',2',3'-trihydroxypropyl)1,2,3,4,5,6-hexahydroxyhexane, but 2-hydroxymethyl-1-(2,3-dihydroxypropoxy)2,3,4,5-cyclopentanetet raol with an ether linkage in the molecule. Such an intermolecular ether linkage was resistant to BCl3 treatment, but nonresistant to 57% HI degradation treatment conducted at 100 degrees C for 60 h, producing 2-hydroxymethyl-1,2,3,4,5-cyclopentanepentaol from calditol as reaction product. Further, it was confirmed that the structure of calditol is essentially a derivative of glycerol, and hydrocarbon chains were conjugated to the glycerol-like site in the structure. The calditol with an ether linkage in the molecule suggested an important role regarding the properties of heat-resistance and acid-resistance observed in Sulfolobales.