Elimination of beta-blockers in sewage treatment plants.

beta-Blockers are used to treat high blood pressure as well as patients recovering from heart attacks. In several studies, they were detected in surface water, thus indicating incomplete degradability of these substances in sewage treatment plants (STPs). In this study, we determined the sorption coefficients (K(D)) and degradation rates of the four beta-blockers sotalol, atenolol, metoprolol and propranolol in sludge from an STP operating with municipal wastewater. The sorption coefficients (K(D), standard deviations in brackets) were determined as 0.04(+/-0.035), 0.04(+/-0.033), 0.00(+/-0.023) and 0.32(+/-0.058) Lg(-1)(COD), and the pseudo-first-order degradation rate constants were estimated to be 0.29(+/-0.02), 0.69(+/-0.05), 0.58(+/-0.05) and 0.39(+/-0.07) Ld(-1)g(-1)(COD) for sotalol, atenolol, metoprolol and propranolol, respectively. These values translate into a typical elimination in STPs (sludge concentrations of 4g(COD)L(-1) and a hydraulic retention time of 6h) of 25%, 37%, 44% and 50% for sotalol, propranolol, metoprolol and atenolol, respectively. These results are also confirmed by measurements in two municipal STPs for atenolol, sotalol and propranolol. The estimated eliminations are slightly too high for metoprolol.

Modeling stochastic load variations in sewer systems.

In wastewater treatment and environmental risk assessments increasing attention is paid to the fate of micropollutants. These are time-consuming, expensive and difficult to detect and quantify. If a substance's load or concentration is subject to high dynamic fluctuations, it is demanding to take representative samples, especially when the "variation" is unknown. Therefore, we developed a concept to model stochastic load variations in sewer systems. We gathered readily available information from existing databases (population and consumption data) and combined it with the characteristics of household activities and appliances. We succeeded in predicting realistic short-term variations of benzotriazole (contained in dishwasher detergents) and validated them with a high-frequency measuring campaign. Benzotriazole stands as an example for other household chemicals, which cannot be measured so easily. All required information used within this case study is also available for other substances and catchments. This allows the forecast of stochastic load variations for many chemical compounds of interest. It helps to plan measuring campaigns, to estimate discharged loads from combined sewer overflows and to have a characteristic input for modeling purposes.

B-cell neoplasia associated gene with multiple splicing (BCMS): the candidate B-CLL gene on 13q14 comprises more than 560 kb covering all critical regions.

Deletions in chromosomal band 13q14.3 occur in >50% of B-cell chronic lymphocytic leukemias (B-CLL) and mantle cell lymphoma, indicating the localization of a tumor suppressor gene involved in the pathomechanism of these diseases. Within a 400 kb recurrently deleted segment at least two minimally deleted subregions had been reported. For the two genes residing in the proximal subregion, initially named LEU1 and LEU2, a pathogenic role has not yet been established. We report here that LEU1 is only a small portion of a large gene, which spans all previously reported critical subregions including the distal subregion. This gene, designated B-cell neoplasia-associated gene with multiple splicing (BCMS), is composed of at least 50 exons spanning >or=560 kb of genomic DNA and is expressed in more than 20 RNA splicing variants. While tissue-specific expression of RNA variants was observed, there was no evidence for the expression of a variant specific for B-CLL. Sequence analysis of the RNA variants suggests that BCMS transcripts belong to the group of non-coding RNAs. The alignment of the gene with all critical subregions provides a strong argument for BCMS being the most likely candidate for the tumor suppressor gene in 13q14 involved in the leukemogenesis of B-CLL. Due to the limited understanding of functional RNAs, however, it remains difficult to prove the pathogenic role of BCMS.

Heterogeneity of the API2-MALT1 gene rearrangement in MALT-type lymphoma.

The translocation t(11;18)(q21;q21), which is the most frequent chromosomal aberration in extranodal marginal zone B cell lymphomas of MALT-type, was characterised in a series of 34 biopsies, including 18 gastric non-Hodgkin's lymphomas (NHL) of MALT-type, six MALT-type NHL of extragastral origin and 10 extranodal large B cell lymphomas (LBL). Based on fluorescence in situ hybridisation, STS-PCR analysis and screening of genomic PAC libraries, a physical map of contiguous DNA probes on chromosome 11 was constructed containing the anti-apoptotic genes API2 and API1 adjacent to the translocation breakpoint. RACE-PCR experiments revealed MALT1 the chromosome 18-derived fusion partner of API2, which has also been reported recently by other groups. RT-PCR analysis and DNA sequencing demonstrated the expression of an API2-MALT1 fusion transcript in 18/24 gastral and extragastral MALT-type lymphomas. In none of 10 LBLs was a translocation specific RT-PCR product detected. Five variants of the fusion transcript were identified and in all instances the open reading frame of the fused portion of the MALT1 gene was maintained. The molecular analysis of these variants allowed the design of optimised assays for the diagnosis of the API2-MALT1 gene rearrangement.

BCMSUN, a candidate gene for B-cell chronic lymphocytic leukemia and mantle-cell lymphoma, has an independently expressed homolog on 1p22-p31, BCMSUN-like.

The most frequent chromosomal imbalance in B-cell chronic lymphocytic leukemia (B-CLL) and mantle-cell lymphoma (MCL) is loss of material from 13q14.3. BCMSUN (previously Leu2, t4, cDNA 1B4) is one of 3 proposed candidate genes isolated from the minimally deleted region. We identified a homolog of BCMSUN, termed BCMSUNL (for BCMSUN-like). Radiation-hybrid mapping with a PCR-amplified fragment and fluorescence in situ hybridization with 2 PAC clones containing coding information for BCMSUNL revealed its localization at 1p22-p31. Interphase fluorescence in situ hybridization, however, revealed that the BCMSUNL gene locus is not part of the critical deletion region of 1p22 in MCLs. Analysis of DNA sequences derived from the respective PAC clones and available in public databases uncovered an intronless structure of BCMSUNL. Compared to BCMSUN, the new gene lacks exon 2 and shows 90.3% homology on the nucleic acid level. Both genes are expressed in peripheral blood lymphocytes from healthy donors as well as B-CLL and MCL tumors, with retention of genetic material at 13q14.3. Therefore, analysis of the candidate tumor-suppressor gene BCMSUN at 13q14.3 must be based on assays that distinguish between the 2 homologous genes.

BCL10 is not the gene inactivated by mutation in the 1p22 deletion region in mantle cell lymphoma.

The BCL10 gene has recently been cloned from the 1p22 breakpoint of the translocation t(1 ;14)(p22;q32) observed in mucosa-associated lymphoid tissue (MALT) lymphoma. BCL10 was shown to be a proapoptotic-signaling gene encoding a protein that contains an amino-terminal caspase recruitment domain (CARD). Mutations within the BCL10 coding region resulting in truncated BCL10 proteins with loss of their proapoptotic function and preservation of their NF-kappaB activating function were detected in MALT lymphoma. Based on these findings it was proposed that BCL10 might have tumor suppressor function. Deletions involving 1p22 are commonly observed in mantle cell lymphoma (MCL). To investigate its role in MCL we have analyzed a series of 15 MCL for deletion and mutation of BCL10. Monoallelic 1p22 deletions were detected by fluorescence in situ hybridization in five of the 15 cases and were shown to affect BCL10 in all cases. BCL10 was screened for mutations by DNA sequencing of RT-PCR amplified transcripts. In none of the 15 MCL cases studied were mutations found in the BCL10 coding region. A previously reported polymorphism exhibiting a silent 24C > G substitution was found in eight MCL cases and in four healthy probands. A missense mutation 13G >T resulting in a substitution of a serine by an alanine was seen in one of the controls. Our results strongly suggest that BCL10 is not the candidate tumor suppressor gene inactivated by deletion or mutation in band 1p22 in MCL.

The ATM gene in the pathogenesis of mantle-cell lymphoma.

BACKGROUND: Mantle-cell lymphoma (MCL) is genetically characterized by the translocation t(11;14)(q13;q32) leading to an overexpression of cyclin-D1, but additional chromosomal abnormalities appear to be required for MCL pathogenesis. PATIENTS AND METHODS: Deletions involving chromosome 11q, which were recently found as recurrent aberrations in MCL, were analyzed at the molecular level in a series of 81 MCL by fluorescence in situ hybridization (FISH) with probes from a contiguous set of yeast artificial chromosomes (YACs) spanning bands 11q14-q24. RESULTS AND CONCLUSIONS: Loss of chromosome 11 material was observed in 37 of the 81 MCL cases (46%). The consensus deletion comprised YAC 801e11 containing the ATM gene. The minimal region of loss was further narrowed with P1-derived artificial chromosome (PAC) probes. This allowed the identification of a deletion confined to the genomic region of ATM, which, together with intragenic mutations found in the coding sequence, suggests a role of ATM as a tumor suppressor gene in MCL.

Mantle cell lymphoma is characterized by inactivation of the ATM gene.

In mantle cell lymphoma (MCL), the translocation t(11;14) is considered the cytogenetic hallmark of the disease. Recently, however, deletion of the chromosomal region 11q22-q23 has been identified as a frequent event in this type of cancer, indicating the existence of a pathogenically relevant tumor suppressor gene in this region. The deleted segment contains the ATM (ataxia telangiectasia mutated) gene. ATM is an interesting candidate as a tumor suppressor gene because constitutive inactivation of the gene predisposes ataxia telangiectasia patients to lymphoid malignancies. To assess the potential involvement of the gene in MCL lymphomagenesis, we performed mutation analysis of ATM in 12 sporadic cases of MCL, 7 of them with a deletion of one ATM gene copy, by using single-strand conformation polymorphism analysis of reverse transcription-PCR-amplified mRNA and subsequent DNA sequencing. In all seven cases containing a deletion of one ATM allele, a point mutation in the remaining allele was detected, which resulted in aberrant transcript splicing, truncation, or alteration of the protein. In addition, biallelic ATM mutations were identified in two MCLs that did not contain 11q deletions. Interestingly, in three cases analyzed, the ATM mutations detected in the tumor cells were not present in nonmalignant cells, demonstrating their somatic rather than germ-line origin. The inactivation of both alleles of the ATM gene by deletion and deleterious point mutation in the majority of cases analyzed indicates that ATM plays a role in the initiation and/or progression of MCL.

Molecular characterization of 11q deletions points to a pathogenic role of the ATM gene in mantle cell lymphoma.

Deletions involving the long arm of chromosome 11 (11q) have been recently found as recurrent chromosome aberrations in mantle cell lymphoma (MCL). In the current study, the incidence and molecular extent of 11q deletions were analyzed in a series of 81 MCL by fluorescence in situ hybridization with probes from a contiguous set of yeast artificial chromosomes (YACs). Loss of chromosome 11 material was observed in 37 of 81 cases (46%). The minimally deleted segment comprised YAC 801e11 containing the ATM gene. To further narrow the minimal region of loss, P1-derived artificial chromosomes mapping to the critical region were isolated and used as probes in cases without aberrations detectable with YACs. This allowed the identification of an ATM deletion that was beyond the resolution of YAC probes. The identification of a minimally deleted segment affecting ATM suggests a pathogenic role of ATM as a tumor suppressor gene in MCL.

Somatic ATM mutations indicate a pathogenic role of ATM in B-cell chronic lymphocytic leukemia.

Deletion in chromosome bands 11q22-q23 is one of the most common chromosome aberrations in B-cell chronic lymphocytic leukemia (B-CLL). It is associated with extensive lymph node involvement and poor survival. The minimal consensus deletion comprises a segment, which contains the ATM gene presenting an interesting candidate gene, as mutations in ATM predispose A-T patients to lymphoid malignancies. To investigate a potential pathogenic role of ATM in B-cell tumorigenesis, we performed mutation analysis of ATM in 29 malignant lymphomas of B-cell origin (B-CLL = 27; mantle cell lymphoma, [MCL] = 2). Twenty-three of these carried an 11q22-q23 deletion. In five B-CLLs and one MCL with deletion of one ATM allele, a point mutation in the remaining allele was detected, which resulted in aberrant transcript splicing, alteration, or truncation of the protein. In addition, mutation analysis identified point mutations in three cases without 11q deletion: two B-CLLs with one altered allele and one MCL with both alleles mutated. In four cases analyzed, the ATM alterations were not present in the germ line indicating a somatic origin of the mutations. Our study demonstrates somatic disruption of both alleles of the ATM gene by deletion or point mutation and thus its pathogenic role in sporadic B-cell lineage tumors.

Differential regulation of vascular endothelial growth factor and its receptor fms-like-tyrosine kinase is mediated by nitric oxide in rat renal mesangial cells.

Under conditions associated with local and systemic inflammation, mesangial cells and invading immune cells are likely to be responsible for the release of large amounts of nitric oxide (NO) in the glomerulus. To further define the mechanisms of NO action in the glomerulus, we attempted to identify genes which are regulated by NO in rat glomerular mesangial cells. We identified vascular endothelial growth factor (VEGF) and its receptor fms-like tyrosine kinase (FLT-1) to be under the regulatory control of exogenously applied NO in these cells. Using S-nitroso-glutathione (GSNO) as an NO-donating agent, VEGF expression was strongly induced, whereas expression of its FLT-1 receptor simultaneously decreased. Expressional regulation of VEGF and FLT-1 mRNA was transient and occurred rapidly within 1-3 h after GSNO treatment. Expression of a second VEGF-specific receptor, fetal liver kinase-1 (FLK-1/KDR), could not be detected. The inflammatory cytokine interleukin-1beta mediated a moderate increase in VEGF expression after 24 h and had no influence on FLT-1 expression. In contrast, platelet-derived growth factor-BB and basic fibroblast growth factor had no effect on VEGF expression, but strongly induced FLT-1 mRNA levels. Obviously, there is a differential regulation of VEGF and its receptor FLT-1 by NO, cytokines and growth factors in rat mesangial cells.

Biallelic mutations in the ATM gene in T-prolymphocytic leukemia.

Ataxia-telangiectasia (AT) is an autosomal recessive disorder characterized by cerebellar ataxia, oculocutaneous telangiectasia, immune deficiency, genome instability and predisposition to malignancies, particularly T-cell neoplasms. The responsible gene, designated ataxia-telangiectasia mutated (ATM), was recently identified by positional cloning in the chromosomal region 11q22.3-23.1 (ref. 4, 5) ATM is 150 kb in length, consists of 66 exons and encodes a nuclear phosphoprotein of approximately 350 kDa (ref. 4-9). Although ATM is considered to be a tumorigenic factor in several human cancers, it has not yet been found mutated in tumors of non-AT patients. Given the marked predisposition of AT patients to develop neoplasms of the T-cell lineage, we analyzed a series of T-cell leukemias (T-prolymphocytic leukemia, or T-PLL) in non-AT patients in search of genomic changes associated with the development of this disease. Among the recurrent aberrations identified, deletion of the chromosome arm 11q was very frequent. Subsequent molecular cytogenetic analyses allowed us to define a small commonly deleted segment at 11q22.3-23.1 in 15 of 24 T-PLLs studied. Since this critical region contained ATM, we further analyzed the remaining copy of the gene in six cases showing deletions affecting one ATM allele. In all six cases, mutations of the second ATM allele were identified, leading to the absence, premature truncation or alteration of the ATM gene product. Thus, our study demonstrates disruption of both ATM alleles by deletion or point mutation in T-PLL, suggesting that ATM functions as a tumor-suppressor gene in tumors of non-AT individuals.

Online detection of REM sleep based on the comprehensive evaluation of short adjacent EEG segments by artificial neural networks.

1. For scientific and clinical requirements the present objective is a robust automatic online algorithm to detect rapid eye movement (REM) sleep from single channel sleep EEG data without using EMG or EOG information. 2. For data preprocessing 20 seconds time periods of the continuous EEG activity are digitally filtered in 7 frequency bands. Then the RMS values of these filtered signals are calculated along segments of 2.5 seconds. The resulting matrix of RMS values is representing information on the power of the signal localized in time and frequency and serves as input to an artificial neural network. A pooled set of EEG data together with the corresponding manual evaluation of the recordings was used in the training process. 3. Afterwards more than 90% of the time periods not belonging to the training set could be correctly labeled into REM and nonREM periods. In comparison to an older algorithm based on RMS values calculated along segments of 20 seconds, the error rate could be reduced by 20%.

Social and developmental influences on reproductive function in female Wied's black tufted-ear marmosets (Callithrix kuhli).

Although marmoset social groups may contain multiple adult females, reproduction is typically limited to one breeding female. A variety of endocrine and behavioral mechanisms have been identified that regulate fertility among female marmosets. In the present study, we assessed the mechanism(s) by which fertility is regulated in female black tufted-ear marmosets, Callithrix kuhli. The reproductive status of 10 daughters aged 2-24 months was evaluated by measuring concentrations of urinary pregnane-diol 3 alpha glucuronide (PdG) and luteinizing hormone (LH). Concentrations of the two hormones were typically low in daughters less than 12 months of age, and the profiles suggested anovulation (mean PdG < 2 micrograms/mg Cr and mean LH < 6 ng/mg Cr). Concentrations of PdG rose dramatically in females older than 12 months. Eight subadult daughters commenced ovulatory function while still living with their family, and the remaining two failed to ovulate. The onset of ovarian function coincided with a change in the social environment in two females, but the remaining six females commenced spontaneous ovarian activity that was not associated with any social or environmental factor (mean age: 15.6 +/- 1.6 months). Ovulatory function was monitored in five daughters while housed in their natal family group, while removed from the natal family group and housed singly, and while paired with an unrelated and unfamiliar male. The ovarian cycles of these females housed in the natal group were characterized by significantly shorter luteal phases and reduced PdG concentrations, relative to when the females were housed on their own, and relative to adult breeding females (n = 6). Stimulatory cues from unfamiliar males were not necessary to trigger regular ovarian function in females. In this species, the regulation of fertility in daughters is a complex combination of behavioral and endocrine factors.

Surrogate data analysis of sleep electroencephalograms reveals evidence for nonlinearity.

We tested the hypothesis of whether sleep electroencephalographic (EEG) signals of different time windows (164 s, 82 s, 41 s and 20.5 s) are in accordance with linear stochastic models. For this purpose we analyzed the all-night sleep electroencephalogram of a healthy subject and corresponding Gaussian-rescaled phase randomized surrogates with a battery of five non-linear measures. The following nonlinear measures were implemented: largest Lyapunov exponent L1, correlation dimension D2, and the Green-Savit measures delta 2, delta 4 and delta 6. The hypothesis of linear stochastic data was rejected with high statistical significance. L1 and D2 yielded the most pronounced effects, while the Green-Savit measures were only partially successful in differentiating EEG epochs from the phase randomized surrogates. For L1 and D2 the efficiency of distinguishing EEG signals from linear stochastic data decreased with shortening of the time window. Altogether, our results indicate that EEG signals exhibit nonlinear elements and cannot completely be described by linear stochastic models.

Discrimination of sleep stages: a comparison between spectral and nonlinear EEG measures.

During recent years, methods from nonlinear dynamics were introduced into the analysis of EEG signals. Although from a theoretical point of view nonlinear measures quantify properties being independent from conventional spectral measures, it is a crucial question whether in practice nonlinear EEG measures yield additional information, which is not redundant to the information gained by spectral analysis. Therefore, we compared the ability of several spectral and nonlinear measures to discriminate different sleep stages. We evaluated spectral measures (relative delta power, spectral edge, spectral entropy and first spectral moment), and nonlinear measures (correlation dimension D2, largest Lyapunov exponent LI, and approximated Kolmogorof entropy K2), and additionally the stochastic time domain based measure entropy of amplitudes. For 12 healthy subjects these measures were calculated from sleep EEG segments of 2:44 min duration, each segment unambiguously corresponding to one of the sleep stages I, II, SWS and REM. Results were statistically evaluated by multivariate and univariate analyses of variance and by discriminant analyses. Generally, nonlinear measures (D2 and L1) performed better in discriminating sleep stages I and II, whereas spectral measures showed advantages in discriminating stage II and SWS. Combinations of spectral and nonlinear measures yielded a better overall discrimination of sleep stages than spectral measures alone. The best overall discrimination was reached even without inclusion of any of the spectral measures. It can be concluded that nonlinear measures yield additional information, which improves the ability to discriminate sleep stages and which may in general improve the ability to distinguish different psychophysiological states. This confirms the importance and practical reliability of the application of nonlinear methods to EEG analysis.

Detection of point mutations in chloroplast genes of Antirrhinum majus L. I. Identification of a point mutation in the psaB gene of a photosystem I plastome mutant.

A point mutation in the plastome-encoded psaB gene of the mutant en:alba-1 of Antirrhinum majus L. was identified by an analysis of chloroplast DNA with a modified PCR-SSCP technique. Application of this technique is indicated when a gene or a group of genes is known in which the point mutation is located. Analysis of primary photosynthetic reactions in the yellowish white plastome mutant indicated a dysfunction of photosystem (PS) I. The peak wavelength of PS I-dependent chlorophyll (Chl) fluorescence emission at 77 K was shifted by 4 nm to 730 nm, as compared to fluorescence from wild-type. There were no redox transients of the reaction center Chl P700 upon illumination of leaves with continuous far-red light or with rate-saturating flashes of white light. The PS I reaction center proteins PsaA and PsaB are not detectable by SDS-PAGE in mutant plastids. Hence, plastome encoded PS I genes were regarded as putative sites of mutation. In order to identify plastome mutations we developed a modified SSCP (single-strand conformation polymorphism) procedure using a large PCR fragment which can be cleaved with various restriction enzymes. When DNA from wild-type and en:alba-1 was submitted to SSCP analysis, a single stranded HinfI fragment of a PCR product of the psaB gene showed differences in electrophoretic mobility. Sequence analysis revealed that the observed SSCP was caused by a single base substitution at codon 136 (TAT-->TAG) of the psaB gene. The point mutation produces a new stop codon that leads to a truncated PsaB protein. The results presented indicate that the mutation prevents the assembly of a functional PS I complex. The applicability to other plastome mutants of the new method for detection of point mutations is discussed.

Cloning and characterization of a 3-N-aminoglycoside acetyltransferase gene, aac(3)-Ib, from Pseudomonas aeruginosa.

A novel gene encoding an aminoglycoside 3-N-acetyltransferase, which confers resistance to gentamicin, astromicin, and sisomicin, was cloned from Pseudomonas aeruginosa Stone 130. Its sequence was determined and found to show considerable similarity to an aac(3)-I gene previously cloned from R plasmids from Enterobacter, Pseudomonas, and Serratia spp. We have designated the genes from the R plasmids and this work aac(3)-Ia and aac(3)-Ib, respectively. The two aac(3)-I genes share 74% nucleotide identity, and their deduced protein products are 88% similar. These data suggest that the genes derive from a common ancestor. Homology between the flanking sequences of both aac(3)-I genes and other resistance determinants known to reside in integron environments was also observed. Intragenic probes specific for either aac(3)-Ia or aac(3)-Ib were used in hybridization studies with a series of gentamicin-, astromicin-, and sisomicin-resistant clinical isolates. Of 59 clinical isolates tested, no isolates hybridized with both probes, 30 (51%) hybridized with the aac(3)-Ia probe, 12 (20%) hybridized with the aac(3)-Ib probe, and 17 (29%) did not hybridize with either probe. These data suggest the existence of at least one other aac(3)-I gene.

Cellular sterol accumulation stimulated by cholesterol 5 beta,6 beta-epoxide in J774 macrophages.

A significant accumulation of cellular free cholesterol and steryl esters is observed in J774 macrophages when cells are exposed to low-density lipoproteins (LDL) containing cholesterol 5 beta,6 beta-epoxide. This cellular sterol accumulation is mainly due to the formation of esterified cholesterol and desmosterol. Cellular steryl esters increased to 39.4 and 22.4 micrograms/mg cell protein with 0.8 microM of cholesterol 5 beta,6 beta-epoxide and 3,5-cholestadien-7-one, respectively, whereas hardly detectable levels were observed with the absence of oxysterols. The total cellular sterols increased 45% above the value of control with cholesterol 5 beta,6 beta-epoxide. The uptake of [3H] cholesteryl oleate-LDL was also enhanced by cholesterol 5 beta,6 beta-epoxide. The rapid displacement of desmosterol with cholesterol was observed when cells were treated with cholesterol 5 beta,6 beta-epoxide or 3,5-cholestadien-7-one in the presence of LDL. Cholesterol 5 beta,6 beta-epoxide became associated with LDL in the culture conditions, and its uptake into J774 cells and the cytotoxicity were reduced significantly by the association with LDL. The comparison of selected oxysterols for their ability to stimulate cellular sterol accumulation indicated that cholesterol 5 beta,6 beta-epoxide is the most potent. Cholesterol esterification was enhanced significantly by cholesterol 5 beta,6 beta-epoxide whereas cholesterol 5 alpha,6 alpha-epoxide and 3,5-cholestadien-7-one produced a modest response. In contrast, although cholestantriol, the metabolic hydrolysis product of cholesterol epoxides, also associated with LDL, it showed no stimulating effect on both cellular sterol content and sterol esterification. These results indicate that some oxysterols, such as cholesterol 5 beta,6 beta-epoxide and possibly 3,5-cholestadien-7-one, stimulate cellular sterol accumulation in J774 macrophages and may play an important role in atherogenesis.

Comparative neurotoxicities of amphotericin B and its mono-methyl ester derivative in rats.

The intracisternal administration of amphotericin B (AmB) and its mono-methyl ester derivative (AME), via direct intraventricular injection (0.01 to 5 mg/ml, 6 microliters) in adult female Wistar rats, revealed that AmB was significantly more toxic than AME, as measured by weight loss, lethargy, death, and central nervous system histopathology. Light and electron microscopy confirmed a greater neurotoxicity for AmB, manifested as edema and modest gliosis extending along and beyond the injection tract. Neuronal degeneration and myelin damage were present in AmB-treated (1 mg/ml) animals but were present only modestly in animals treated with AME at a fivefold greater concentration. Intravenous administration of AmB to adult female Wistar rats as five daily doses of 5 mg/kg of body weight resulted in significant weight loss and some deaths. Histopathologic examination of the brains, spinal cords, and sural nerves of surviving animals revealed neurotoxicity manifested by neuronal degeneration, gliosis, and myelin edema. In sharp contrast, similar treatment with AME at a 10-fold greater dose resulted in neither death nor significant neurotoxicity. The administration of five daily doses of a mixture of AME-AmB (9:1; wt/wt) at 50 mg/kg of body weight resulted in neurotoxicity. These results indicate that AmB exhibits significantly greater in vivo neurotoxicity than AME.