Sympathetic and parasympathetic innervation in hepatocellular carcinoma

Autonomic nervous system plays an important role in the development of multiple cancers via regulating cancer cell proliferation, differentiation, apoptosis, migration and invasion. However, no detailed studies have been performed to study the role of autonomic nerve fibers in hepatocellular carcinoma (HCC) as well as its correlation with the progression of HCC. Here, we examined the distribution of the autonomic nerve fibers and analyzed the correlation between autonomic nerve fibers and the pathological characteristics of HCC patients. The transcriptional expression of adrenergic and cholinergic receptors was evaluated in both hepatoma cell lines and primary hepatoma cells. In addition, we summarized the function of receptors for neurotransmitters in different cancers recently reported. Our findings indicate that tissue of liver cancer is innervated by both sympathetic and parasympathetic nerves and the density of the nerve fibers is associated with patients' poor prognosis. Additionally, we report that adrenergic receptors β2 and cholinergic receptors α7, M1 and M3 are high expressed in both hepatoma cell lines and primary hepatoma cells, indicating these receptors may play essential roles in the regulation of autonomic nervous system triggered HCC.

A Brain Tumor/Organotypic Slice Co-culture System for Studying Tumor Microenvironment and Targeted Drug Therapies

Brain tumors are a major cause of cancer-related morbidity and mortality. Developing new therapeutics for these cancers is difficult, as many of these tumors are not easily grown in standard culture conditions. Neurosphere cultures under serum-free conditions and orthotopic xenografts have expanded the range of tumors that can be maintained. However, many types of brain tumors remain difficult to propagate or study. This is particularly true for pediatric brain tumors such as pilocytic astrocytomas and medulloblastomas. This protocol describes a system that allows primary human brain tumors to be grown in culture. This quantitative assay can be used to investigate the effect of microenvironment on tumor growth, and to test new drug therapies. This protocol describes a system where fluorescently labeled brain tumor cells are grown on an organotypic brain slice from a juvenile mouse. The response of tumor cells to drug treatments can be studied in this assay, by analyzing changes in the number of cells on the slice over time. In addition, this system can address the nature of the microenvironment that normally fosters growth of brain tumors. This brain tumor organotypic slice co-culture assay provides a propitious system for testing new drugs on human tumor cells within a brain microenvironment.

BMP-2 promotes chondrogenesis of rat adipose-derived stem cells by using a lentiviral system

Osteoporosis poses a major public health threat in aging societies. Adipose-derived stem cells (ADSCs) are multipotent adult stem cells that have the ability to yield mesenchymal stem cells, and have the potential to undergo osteogenesis and bone regeneration. Bone morphogenetic proteins (BMPs) have been demonstrated to upregulate bone gene expression after mechanical injury and to improve bone injury repair. This study aimed to produce BMP-2 expression in ADSCs by using lentiviral vectors. Subcutaneous adipose tissue from 4-week-old male Sprague-Dawley rats was used. Oil red O staining was used to detect adipocyte formation from ADSCs. Induction of ADSC osteogenesis was confirmed with Alizarin red S staining. The recombinant lenti-hBMP-2/neo was constructed to infect ADSCs, BMP-2 expression was measured by immunoblotting analysis, and cellular alkaline phosphatase levels were examined. We found that >70% of ADSC cells could be induced to differentiate into osteocytes or adipocytes. Under osteogenic induction, ADSCs showed increased intracellular calcium deposition, the formation of calcium tubercles, and the disappearance of cellular structures in calcium tubercles. After infection of ADSCs by lenti-hBMP-2/neo, BMP-2 was expressed after doxycycline induction. We, thus, conclude that ADSCs maintain vigorous growth ex vivo and possess stem cell-like properties. When infected with lenti-hBMP-2/neo, ADSCs can be induced to promote BMP-2 expression.

Observation of photorefractive surface waves in self-defocusing LiNbO3:Fe crystal

Photorefractive (PR) surface waves (SWs) in self-defocusing LiNbO(3):Fe are studied theoretically and experimentally. We demonstrate that SWs can also be formed in a self-defocusing nonlinear medium and that the nonlocal nonlinearity (such as the diffusion component of PR nonlinearity in this Letter) is the essential cause. The forming process of PR SWs with a self-deflection course of light beams has been observed. The results indicate the possibility of concentrating light energy in self-defocusing media, taking advantage of SWs.

Tissue inhibitor of metalloproteinase-1 decreased chemosensitivity of MDA-435 breast cancer cells to chemotherapeutic drugs through the PI3K/AKT/NF-кB pathway

TIMP-1 is well known to be capable of inhibiting apoptosis. Elevated levels of TIMP-1 in tumor tissue have been shown to be strongly associated with a poor response to chemotherapy. In this study, using conventional cytotoxic drugs commonly used in the treatment of breast cancer, we investigated how TIMP-1 influenced the efficacy using breast cell lines. Our data demonstrated that overexpression of TIMP-1 could significantly decrease the sensitivity of MDA-435 breast cancer cells to epirubicin and paclitaxel. TIMP-1 can potently activate phosphatidylinositol 3-kinase (PI3K)/Akt and nuclear factor-kappaB (NF-кB) signaling. Furthermore, the TIMP-1-induced attenuation of the effect of epirubicin and paclitaxel was reversed by the PI3K/Akt chemical inhibitor LY294002 and the NF-кB inhibitor pyrrolidine dithiocarbamate (PDTC), showing that the PI3K/Akt and NF-кB signaling pathway was involved in the TIMP-1-induced effect on chemoresistance. Taken together, our results indicate that TIMP-1 decreased chemosensitivity through the PI3K/Akt/NF-кB signal transduction pathway in MDA-435 breast cancer cells.

An investigation of models of the IP3R channel in Xenopus oocyte

We consider different models of inositol 1,4,5-trisphosphate (IP(3)) receptor (IP(3)R) channels in order to fit nuclear membrane patch clamp data of the stationary open probability, mean open time, and mean close time of channels in the Xenopus oocyte. Our results indicate that rather than to treat the tetrameric IP(3)R as four independent and identical subunits, one should assume sequential binding-unbinding processes of Ca(2+) ions and IP(3) messengers. Our simulations also favor the assumption that a channel opens through a conformational transition from a close state to an active state.

Schwann cell proliferation during Wallerian degeneration is not necessary for regeneration and remyelination of the peripheral nerves: axon-dependent removal of newly generated Schwann cells by apoptosis

Peripheral nerve injury is followed by a wave of Schwann cell proliferation in the distal nerve stumps. To resolve the role of Schwann cell proliferation during functional recovery of the injured nerves, we used a mouse model in which injury-induced Schwann cell mitotic response is ablated via targeted disruption of cyclin D1. In the absence of distal Schwann cell proliferation, axonal regeneration and myelination occur normally in the mutant mice and functional recovery of injured nerves is achieved. This is enabled by pre-existing Schwann cells in the distal stump that persist but do not divide. On the other hand, in the wild type littermates, newly generated Schwann cells of injured nerves are culled by apoptosis. As a result, distal Schwann cell numbers in wild type and cyclin D1 null mice converge to equivalence in regenerated nerves. Therefore, distal Schwann cell proliferation is not required for functional recovery of injured nerves.

The molecular features of membrane perturbation by anaesthetic steroids: a study using differential scanning calorimetry, small angle X-ray diffraction and solid state 2H NMR

We have studied the interactions of the anaesthetic steroid alphaxalone and its inactive isomer delta 16-alphaxalone with model membrane bilayers using differential scanning calorimetry, small angle X-ray diffraction and solid state NMR. Our data show that the anaesthetic steroid broadens the membrane phase transition and increases the ratio of gauche to trans conformers in the membrane. Delta 16-Alphaxalone has only small effects on membrane and incorporates to a limited degree in the bilayer. The amphipathic anaesthetic steroid alphaxalone is located near the membrane interface (the junction of the polar and hydrophobic regions of the phospholipids forming the bilayer). It orients with its long axis parallel to the chains of the lipid membranes and its 3 alpha-hydroxyl group near the sn-2 carbonyl. Anchoring of the steroid at the membrane interface and imperfect packing with the bilayer chains may be involved in membrane perturbation and eventually lead to anaesthesia.

Preparation of a respiratory syncytial virus human reference serum for use in the quantitation of neutralization antibody

Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infection in infants, young children and the elderly. Yet, the development of a vaccine to protect against RSV infection still remains an unmet need. At present, immune responses to experimental vaccines under investigation are usually evaluated by ELISA and/or by neutralization assays against RSV. However, both types of assays are generally performed somewhat differently at different laboratories. An important step towards standardization of serology is the use of a standard human reference serum enabling normalization of results generated within and between laboratories. To fill this need, we prepared and characterized a human reference serum against the A2 strain of respiratory syncytial virus. The serum represents a pool of more than 400 individual human sera obtained from commercial sources. The sera were screened and selected on the basis of individual RSV neutralization titers. A final neutralization titer of 973 (95% C.I., 884-1072) was assigned to the final reference serum pool after it was tested three times in the presence of 10% guinea pig complement and a titer of 286 (95% C.I., 243-337) was assigned to the serum when it was tested in the absence of an exogenous complement source. Sterilely reconstituted lyophilized aliquots of the serum exhibited a stable neutralization titer for at least 1 month at room temperature and at 4 degrees C, as well as after 5 weekly freeze-and-thaw cycles at -20 degrees C. In the lyophilized state, the neutralization titer of the lyophilized reagent was stable for at least 6 months, the last time point tested. Two additional smaller pools of serum with high and medium neutralization titers of 2692 and 575, respectively, were also produced in parallel for use as positive controls and were designated as control sera. The reference serum can be used to normalize neutralization and/or other RSV-specific assay results from different laboratories and the control sera can be used for quality control purposes or as part of a panel to test operator proficiency. Individual lyophilized aliquots of the reference and control sera may be obtained from the US National Institute of Allergy and Infectious Diseases (NIAID) Reference Reagent Repository.

Evaluation of adaptive responses to cisplatin in normal and mutant cell lines with mutations in recombination repair pathways

Cell lines mutant in specific DNA repair pathways were used to determine if these pathways are involved in adaptive responses. For these studies, the effect of deficiencies in homologous recombination repair (HR) were studied in the parental AA8 and mutant (irs)ISF cell line pair and for deficiencies in the nonhomologous endjoining (NHEJ) pathway in the mouse MEF parental and Ku80 mutant cell line pair. The results showed that the XRCC3 mutation in the HR-deficient mutant inhibited adaptive responses to low doses of cisplatin and radiation. The parental lines showed transient adaptive responses to both low-dose cisplatin and radiation treatment. For the mouse MEF and the Ku80 cells, no adaptive responses were observed in either cell line. However, there was an initial transient sensitization response followed by partial recovery. Thus, it appears that the HR repair system may be involved in the adaptive response to cisplatin and radiation. For the NHEJ repair system the question could not be answered since no adaptive responses were evident in the parental line.

The evaluation of thermal cisplatin sensitization in normal and XP human cells using mild hyperthermia at 40 and 41 degrees C

The effect of protracted mild hyperthermia treatment at 40 and 41 degrees C given, concurrently with cisplatin, was evaluated in human normal AG1522 and human mutant XPA cells. While mild hyperthermia itself for up to 6 hours showed little to no toxic effects, it did result in significant sensitization of response to cisplatin treatment. Sensitization for the normal and mutant cell line was comparable, indicating that nucleotide excision repair (NER) probably does not have a role in this process. For the 41 degrees C heating, thermotolerance developed and heating times greater than 4 hours resulted in protective effects from cisplatin cytotoxicity. This was not observed for heating at 40 degrees C for up to 6 hours.

Cisplatin sensitization by concurrent mild hyperthermia in parental and mutant cell lines deficient in homologous recombination and non-homologous endjoining repair

The effect of mild hyperthermia on cisplatin sensitization was examined in two cell line pairs, CHO parental AA8 and irsISF, an XRCC3 mutant (deficient in homologous recombination repair), and mouse parental MEF and knockout Ku80 mutants (deficient in non-homologous endjoining repair). The results showed that mild hyperthermia 40, 41 and 42 degrees C given concurrently with cisplatin treatment caused significant sensitization. The degree of sensitization was comparable for the parental and mutant lines, indicating that these repair pathways were likely not involved in cisplatin thermal sensitization. The shorter concurrent treatments cause a larger sensitization than the longer treatments. The reasons for this are not clear, but thermotolerance may be a factor.

Is DNA polymerase beta important in thermal radiosensitization?

Thermal radiosensitization was tested in a pair of mouse cells (MB+ wild-type and MB-, DNA polymerase beta knockout cells) and in human breast carcinoma cells (MCF7 wild-type and C716 transfected to give elevated DNA polymerase beta expression). Results showed that neither reducing DNA polymerase beta (involved in base excision repair) nor increasing it had any significant effect on thermal radiosensitization. The data indicated that polymerase beta was not involved in thermal radiosensitization, and since hyperthermia is known as a radiation damage repair inhibitor, other repair pathways might be involved and need to be explored.

Comparison of human tumour cell responses to cisplatin and ZD0473 with and without irradiation

Three pairs of human tumour cell lines, with one line of each pair resistant to cisplatin, were used to compare the effects of cisplatin and ZD0473 on cellular toxicity and radiosensitization. Whilst all three cell line pairs had one line that was resistant to cisplatin, for ZD0473 the lung tumour HTB56cp and cervical carcinoma ME180 cell lines did not express resistance to their HTB56 and SHA counterparts, respectively. Only the ovarian carcinoma line A2780cp showed resistance to ZD0473 compared to its counterpart A2780S. For radiosensitization both cisplatin and ZD0473 show additive and subadditive effects in the ovarian carcinoma lines, and additive and superadditive effects in the cervical carcinoma and lung tumour cell lines. In fact in the lung tumour cell lines ZD0473 appeared to be a more effective radiosensitizer than cisplatin.

Comparison of response to radiation, hyperthermia and cisplatin in parental and polymerase beta knockout cells

The role of polymerase beta in response to radiation, cisplatin and hyperthermia was examined in a pair of mouse cell lines, comprising a normal parental line and a derivative with polymerase beta knockout. Cell survival was assessed using the colony survival assay. For irradiation, there was no difference in response between the two cell lines. Treatment with cisplatin for 1 h showed a large increase in resistance in the mutant cell line. The results with hyperthermia were more complex. The mutant was more resistant to 45 degrees C heating, but was slightly more heat sensitive than the wild type at 41 degrees C. Thus, in summary, while the knockout of polymerase beta did not alter radiation sensitivity, it did increase resistance to cisplatin and induced resistance to hyperthermia at higher temperatures (45 degrees C).

Comparison of hyperthermia radiosensitization and DNA polymerase inactivation in human normal and melanoma cell lines of different radiosensitivities

Two human melanoma cell lines (one radiosensitive, HT144 and one radioresistant, SK Mel-3) and one normal human fibroblast (AG1522) were evaluated for thermal radiosensitization and the thermal enhancement ratios (TERs) were calculated. These were compared with residual polymerase activity to determine if this activity could be used to predict TERs. In all three cell lines, there was a good correlation between TER and residual polymerase alpha or beta activity. Polymerase beta was more sensitive than polymerase alpha as an indicator for TER. There were small cell line-dependent differences (not related to radiosensitivity) among the correlation curves, indicating that for each cell/tumor-type polymerase activity, vs. TER may have to be calibrated.

Thermal radiosensitization and repair inhibition in human melanoma cells: a comparison of survival and DNA double strand breaks

Human melanoma cells (SK-mel-3) were treated with combinations of radiation and hyperthermia treatment and survival (using the colony forming assay) and DNA double strand breaks (dsb's) (using pulsed field gel electrophoresis) were measured for immediate and delayed plating. The cells were treated in plateau phase, so that delayed plating would result in repair of potentially lethal damage (PLD). Delayed plating showed PLDR for both the survival and the dsb end-point. One hour of heating after irradiation showed a temperature dependent increase in radiosensitization for both the survival endpoint and the dsb endpoint for the temperature range from 42 to 45 degrees C. One hour of heating at 43 degrees C after irradiation resulted in the partial inhibition of PLDR and recovery of dsb's. For heating at 45 degrees C the inhibition of dsb repair was complete. There was good correlation between the survival endpoint and the dsb endpoint for the thermal radiosensitization for both the immediate plating and the PLDR protocols. These data indicate that hyperthermia inhibition of repair of PLD is probably due to the inhibition of dsb rejoining. These correlations were made at the same dose levels for survival and dsb analysis, thus avoiding the potential complications of many earlier studies which used much higher doses for dsb analysis than for survival studies.

Development of a fluorescent focus identification assay using serotype-specific monoclonal antibodies for detection and quantitation of rotaviruses in a tetravalent rotavirus vaccine

A fluorescent focus identification assay (FFIDA) was developed for use in experimental studies and for quantitation of the components in a tetravalent live oral rotavirus vaccine. The assay utilizes four serotype-specific neutralizing monoclonal antibodies (MAb) to detect and quantify individual rotaviruses by immunofluorescence staining of fixed virus-infected monkey kidney cells. In mixed virus infections, all four MAb, W1 (serotype 1), 1C10 (serotype 2), R1 (serotype 3), and S4 (serotype 4), specifically stain the relevant homologous serotype without exhibiting any cross-reactivity against the other serotypes. Furthermore, the test is sensitive enough to differentiate at least twofold (0.3 log) differences in virus titer. The results of testing four individual experimental vaccine lots three or more consecutive times showed that all four lots contained similar proportions of the four vaccine strains as detected by the classical plaque neutralization identification test. The rapidity and efficiency of the FFIDA are desirable attributes that make it suitable for use in studies requiring identification and quantitation of one or more of the four major rotavirus serotypes.

The use of high-resolution solid-state NMR spectroscopy and differential scanning calorimetry to study interactions of anaesthetic steroids with membrane

We have used a combination of high-resolution solid-state 13C-NMR and DSC (differential scanning calorimetry) to study the distinctively different thermotropic and dynamic properties of the anaesthetic steroid alphaxalone and its inactive congener delta16-alphaxalone in dipalmitoylphosphatidylcholine (DPPC) model membranes. In the solid-state 13C-NMR, the techniques included cross polarization (CP) and/or magic angle spinning (MAS). The observed data revealed the following important results. (a) DSC as a bulk method showed that the active steroid lowers the main phase transition temperature and broadens the pretransition more significantly than the inactive congener. The 13C-CP/MAS experiments allowed us to detect the pretransition temperature in the alphaxalone-containing preparation, which was not discernible in DSC. (b) The chemical shift values varied with temperature, indicating different degrees of trans-gauche isomerization in the lipid acyl chains when the bilayer is in the liquid crystalline phase. (c) Only specific additional peaks appeared in the 13C-CP/MAS spectra when each of the steroids was present in the preparation. delta16-alphaxalone gives rise to more additional peaks than alphaxalone, indicating a different mobility of the corresponding molecular moiety in the phospholipid bilayer environment. (d) The relative intensities of these peaks also confirmed that alphaxalone is fully incorporated in the bilayer, whereas delta16-alphaxalone is only partially so. These results suggest that the differential effects of these two analogues in the membrane may, at least in part, explain the reason for their different biological activities.

Topography and thermotropic properties of cannabinoids in brain sphingomyelin bilayers

In our previous publications we compared the locations of the biologically active (-)-delta 8-tetrahydrocannabinol (delta 8-THC) with that of its inactive analog O-methyl-(-)-delta 8-tetrahydrocannabinol (Me-delta 8-THC) in the liquid crystalline phase of partially hydrated dimyristoylphosphatidylcholine (DMPC) bilayers (Mavromoustakos et al. (1990) Biophys. Acta 1024, 336-344; Yang et al. (1993) Life Sci. 53, 117-122). delta 8-THC was shown to localize itself preferentially in the vicinity of the membrane interface with its phenolic hydroxyl group anchored near the carbonyl groups of DMPC while the more lipophilic Me-delta 8-THC is located deeper towards the center of the bilayer. In the present publication we studied and compared the topography of the two analogs in the gel phase of brain sphingomyelin bilayers. Again we found that delta 8-THC is located near the membrane interface approximately 15 A from the center of the bilayer while its inactive analog localizes deeper in the bilayer at an average site only 8 A from the center of the membrane bilayer. It thus, appears that both analogs preferentially localize in distinct sites within the membrane bilayer which are independent of the mesomorphic state and the nature of the phospholipid. Our results suggest that in the more complex environment of biological membrane which is composed of different phospholipids and proteins the two analogs are expected to prefer different average locations within the bilayer, a property which may in part explain the observed differences in their biological activities.

The conformational properties of the antineoplastic ether lipid 1-thiohexadecyl-2-O-methyl-S-glycero-3-phosphocholine

Thio analogs of platelet activating factor (PAF) are of great interest because they exhibit antineoplastic properties both in vitro and in vivo. In contrast to most known anticancer agents, these lipids appear not to act through the synthesis and function of DNA and, therefore, offer a new avenue of approaching cancer chemotherapy. We have examined the conformational properties of 1-thiohexadecyl-2-O-methyl-S-glycero-3-phosphocholine (ET-S-16-OCH3) in organic solvents and in micelles. The conformational analysis was based on a combination of 1D, 2D NMR spectroscopy and molecular graphics. 1H and 13C spin lattice relaxation time (T1) experiments were also performed to study the dynamic properties of this molecule. The picture emerging from these studies is as follows. The alkyl chain of ET-S-16-OCH3 is the most mobile part of the molecule both in CDCl3/CD3OD and in micelles and exists as a mixture of interconverting conformers including an extended all trans and several low energy conformers with one or more gauche segments. This creates a twisting of the chain and facilitates a spatial communication between the alkyl chain and the glycerol backbone as well as between the alkyl chain and the headgroup. The methylene groups of the thioglycerol backbone and the headgroup are the least mobile while the methine group of the thioglycerol backbone appears to have an intermediate mobility. The conformation of the thioether lipid in the two media may be of relevance during its interaction with its site of action, the cellular membrane. Such a conformation may also play an important role in determining the selectivity of this interaction with different cell membranes.

Studies on the thermotropic effects of cannabinoids on phosphatidylcholine bilayers using differential scanning calorimetry and small angle X-ray diffraction

We have studied the thermotropic properties of a wide variety of cannabinoids in DPPC bilayers. The molecules under study were divided into four classes: (a) classical cannabinoids possessing a phenolic hydroxyl group; (b) delta9-THC metabolites with an additional hydroxyl group on the C ring; (c) non-classical cannabinoids, and (d) cannabinoids with a protected phenolic hydroxyl group. The results showed that the first three groups have similar effects on the thermotropic properties of DPPC bilayers up to x = 0.05 (molar ratio) and that these effects do not parallel their biological activity. For concentrations less than x = 0.01, cannabinoids affect mainly the pretransition temperature in a progressive manner until its final abolishment. At x = 0.05, they further affect the main phase transition by lowering its phase transition temperature and broadening its half width. At high concentrations the thermograms have multiple components, indicating that membranes are no longer homogeneous but rather consist of different domains. At these concentrations cannabinoids with more hydroxyl groups give simpler thermograms. Low concentrations of cannabinoids in group d affect significantly the pretransition temperature, while high concentrations affect only marginally the main phase transition by slightly lowering its temperature and broadening its half width. These results point out the importance of the phenolic hydroxyl group in inducing membrane perturbations. The d-spacing data from our small angle X-ray diffraction experiments show that delta8-THC produces significant structural changes in the lipid bilayer, including the gel-phase tilting angle, the intermolecular cooperativity and the gauche:trans conformer ratio. Conversely, the inactive analog Me-delta8-THC does not cause drastic changes to the bilayer structure.

Cell killing, DNA polymerase inactivation and radiosensitization to low dose rate irradiation by mild hyperthermia in four human cell lines

Four human cell lines (one fibroblast, two melanoma and one glioma) were evaluated for their responses to hyperthermia and thermalradiosensitization. For mild hyperthermia (40-42 degrees C), there was little to no chronic thermotolerance development during protracted heating for up to 72 h. In addition, there was no significant thermotolerance for polymerase inactivation during mild hyperthermia. For high temperature hyperthermia, polymerase beta was more thermal sensitive than aphidicolin sensitive polymerase alpha + delta + epsilon, (termed polymerase alpha) but during mild hyperthermia ther relative sensitivities were reversed. Polymerase beta was resistant to mild hyperthermia and polymerase alpha was very sensitive. Within each cell line there was a correlation between polymerase alpha inactivation and the degree of radiosensitization (TER) and amongst the cell lines the most radiation resistant cell line had less polymerase alpha inactivation than the most sensitive cell line for similar values of TER's. These data indicate that, amongst the cell lines, radiosensitivity and polymerase alpha sensitivity may influence TER and that for a given cell line, or possibly tumour, polymerase alpha inactivation may have potential as an indicator to determine TER for mild hyperthermia treatments in radiosensitization to low dose rates.

Effects of the anesthetic steroid alphaxalone and its inactive delta 16-analog on the thermotropic properties of membrane bilayers. A model for membrane perturbation

We have studied in detail the effects of the anesthetic steroid alphaxalone and its inactive analog delta 16-alphaxalone on the thermotropic properties of model membranes using differential scanning calorimetry (DSC). The results obtained showed that, for model membranes from hydrated dipalmitoylphosphatidylcholine (DPPC), dioleoylphosphatidylcholine (DOPC), and egg sphingomyelin, the biologically active analog significantly broadened the phase transition, in contrast to the inactive one which produced only marginal effects. Also, alphaxalone abolished the pretransition in these preparations whereas its delta 16-analog only broadened it. However, in DPPE bilayers almost no differences were observed in the effects produced by the two analogs. These results suggest that the ability of the two steroids to perturb membranes is lipid dependent. Comparisons between the effects of the two steroids on lipid/cholesterol model membranes revealed that delta 16-alphaxalone excluded cholesterol from lipid/cholesterol/delta 16-alphaxalone ternary systems whereas alphaxalone enhanced the effects of cholesterol and reduced the cooperativity in the binary phospholipid/cholesterol system. In an attempt to determine whether the different thermotropic effects of the two steroids on model membranes were due to (a) differences in their ability to perturb the bilayers; (b) different extents of incorporation into the bilayer, solid state 2H-NMR was applied using specifically deuterated steroids. The 2H-NMR data showed that alphaxalone incorporated fully into the membrane bilayer up to a molar concentration of 20%, while its inactive analog did only up to a concentration of 1%. To compare the abilities of the two steroids to perturb membrane preparations when both analogs were present in equal amounts in the membrane, the effects of very low steroid concentrations on DPPC bilayers were studied using DSC. The experiment showed that alphaxalone perturbed the membrane bilayers more effectively than its inactive analog. These results strongly suggest that the small structural differences between the two steroids are responsible for the observed differences in their abilities to perturb membranes, possibly because of differences in the packing of these two molecules within the bilayers.

Stepdown hyperthermia in human melanoma cells: effects on protracted mild hyperthermia for survival and DNA polymerase inactivation

Human melanoma cells have been used to evaluate whether stepdown heating (SDH) could increase the effectiveness of long-duration mild hyperthermia (LDMH). The effects of these treatments were also evaluated on cell survival and DNA polymerase inactivation. Short treatments (30 min) at 43 degrees C did not result in much SDH effect for subsequent protracted heating at 40 degrees C. The effect on DNA polymerases was also very small. However, heating at 44 degrees C for 30 min had a large SDH heating effect on subsequent heating at 40 degrees C and 41 degrees C. The SDH effect occurred mainly in the first 5-10 h of subsequent LDMH and, at longer heating times, the rate of cell killing was reduced. The 44 degrees C SDH effect was also observed on DNA polymerase inactivation. Comparing the degree of cell killing and polymerase inactivation showed a good correlation for the various SDH protocols.

Small angle X-ray diffraction and differential scanning calorimetric studies on O-methyl-(-)-delta 8-tetrahydrocannabinol and its 5' iodinated derivative in membrane bilayers

We have previously studied and compared the location of (-)-delta 8-tetrahydrocannabinol (delta 8-THC) with that of O-methyl-delta 8-THC (Me delta 8-THC) in the membrane using partially hydrated dimyristoylphosphatidylcholine (DMPC) bilayers ((Mavromoustakos et al. (1990) Biophys. Acta 1024, 336-344; Yang et al. (1993) Life Sci. 53, 117-122). delta 8-THC was found to be located near the membrane interface with its phenolic hydroxyl group anchored near the carbonyl groups of DMPC while the more lipophilic Me-delta 8-THC is located deeper in the membrane bilayer. Parallel experiments using Me-delta 8-THC and its 5'-iodo analog (5'-I-Me-delta 8-THC) allowed us to determine the topography of these two molecules in the bilayer. Our results from small angle X-ray diffraction and differential scanning calorimetry (DSC) combined with previous data on the orientation of Me-delta 8-THC in model membranes, led us to the conclusion that these molecules intercalate between contiguous acyl chains in the lipophilic moiety of the membrane bilayer. The terminal iodo group in 5'-I-Me-delta 8-THC was found to reside in a region extending approx. +/- 5 A from the center of the bilayers. The location of Me-delta 8-THC in the membranes as well as its orientation may explain its inability to effectively perturb the bilayer lipid chains.

Effect of protracted mild hyperthermia on polymerase activity in a human melanoma cell line

Radioresistant human melanoma SkMel-3 was evaluated with its sensitivity to thermal cell killing and polymerase inactivation. Cells were heated from 40 to 45 degrees C and demonstrated no thermal tolerance development for any of the temperatures tested. In addition, at 45 degrees C the heat survival curve showed a large shoulder indicating capacity for accumulation of sublethal heat damage. Also at 45 degrees C heating polymerase beta was more sensitive than polymerase alpha + delta + epsilon. At 42 degrees C, the polymerase sensitivities were nearly the same but at the lower temperatures (41 and 40 degrees C) polymerase beta became progressively more resistant than the polymerase alpha + delta + epsilon. Thus, mild hyperthermia effects may be different than high temperature hyperthermia and may be related to polymerase alpha + delta + epsilon activity.

Topography of alphaxalone and delta 16-alphaxalone in membrane bilayers containing cholesterol

We have used small-angle X-ray diffraction and differential scanning calorimetry (DSC) to study the topographies of alphaxalone and its biologically inactive analog delta 16-alphaxalone in dimyristoylphosphatidylcholine (DMPC) and DMPC/cholesterol model membranes. Diffraction patterns were obtained and analyzed for preparations of bilayers without and with the steroids. Temperature dependence of the total period repeat distance (d-spacing) allowed us to identify equivalent temperatures at which the preparations had similar d-spacing and were in the same mesomorphic state. The combination of X-ray and DSC data showed that the anesthetic steroid alphaxalone broadens the membrane phase transition and increases the ratio of gauche: trans conformers in the membranes in contrast to the inactive steroid delta 16-alphaxalone which affects the membranes only marginally. In model DMPC membranes alphaxalone and delta 16-alphaxalone are located near the bilayer interface. This location is maintained by alphaxalone when cholesterol is incorporated in the bilayer as evidenced by the X-ray measurements. However, when delta 16-alphaxalone is incorporated in cholesterol containing bilayers, a decrease in the electron density profile of the preparation is observed. This can be explained by invoking the formation of a delta 16-alphaxalone-cholesterol complex. The delta 16-alphaxalone complex shows no periodicity and is therefore, not detected in the X-ray diffraction experiment. Presumably, this complex forms aggregates either on the surface or inside the bilayer. This explanation corroborates DSC results which show that delta 16-alphaxalone sharpens the phase transition of DMPC/cholesterol preparations, an indication that some cholesterol is excluded from the bilayer preparation after the addition of the biologically inactive steroid.

Conformational analysis of the prototype nonclassical cannabinoid CP-47,497, using 2D NMR and computer molecular modeling

In an effort to determine the stereochemical requirements for pharmacological activity among the series of nonclassical cannabinoids synthesized at Pfizer, we have studied the conformational properties of the parent bicyclic analog CP-47,497. For this study, we have used a combination of solution NMR and theoretical computational approaches. The energetically favored conformation has the phenolic ring almost perpendicular to the cyclohexanol ring which exists in a chair conformation. The OH bond of the phenol is preferentially coplanar with the aromatic ring and points toward the C2 ring proton, while the dimethylheptyl side chain adopts a conformation almost perpendicular to the aromatic ring. The conformational features of this nonclassical cannabinoid analog closely resemble those of its classical counterparts. The only apparent difference is the small dihedral angle (psi 1 = 62 degrees) between the planes of the two rings of CP-47,497 compared to that of the tricyclic tetrahydro- or hexahydrocannabinol analogs (psi 1 = 137 degrees). However, CP-47,497 can be perfectly superimposed over the respective tricyclic analog by rotation around the Ph-cyclohexyl bond (C6-C7 bond) and assume a conformation which is energetically higher than the preferred one by 3.0 kcal/mol. It can be argued that such a conformation may be acquired by the nonclassical analog during its interaction with the active site.

[Applied anatomy and clinical application of the reverse dorsal metacarpal flap]

The dorsal metacarpal vessels contribute to the fascial plexus which supplies the skin of the dorsum of the hand. We have successfully used 11 reverse dorsal metacarpal flap based on the dorsal metacarpal arteries. The design and use of the reverse dorsal metacarpal flap are described.

Small angle X-ray diffraction studies of (-)-delta 8-tetrahydrocannabinol and its O-methyl analog in membranes

Small angle X-ray diffraction was used to study the topography of (-)-delta 8-tetrahydrocannabinol (delta 8-THC) and its pharmacologically inactive methoxy analog (-)-O-methyl-delta 8-tetrahydrocannabinol (Me-delta 8-THC) in a membrane. The membrane preparations were partially hydrated dimyristoylphosphatidylcholine (DMPC) bilayers. Comparisons between electron density profiles from the drug-containing and drug-free membranes showed that the amphipathic delta 8-THC residues near the interface of the bilayer where the polar phenolic OH of the drug molecule is oriented towards the corresponding polar side of the phospholipid bilayer. Conversely, the highly hydrophobic Me-delta 8-THC distributes deeper in the bilayer away from the interface. Our results point out these two structurally-related, but pharmacologically very different, cannabinoids interact with membranes in strikingly different manners. This observation may, in part, explain the different pharmacological properties of the two cannabinoids.

[Prevention of reperfusion injury of an ischemic flap: an experimental study]

Oxygen-derived free radicals are important mediators of tissue injury in experimental island skin flaps that have been subjected to prolonged ischemia (vascular occlusion) followed by reperfusion. In this study, the role of oxygen free radical scavenger, SOD, and a herb, salvia miltiorrhiza, in the protection of cellular damages during total ischemia and reperfusion was study in the epigastric island skin flaps in experimental rats with electron microscopy and the assessment of survival of the flaps. Control flaps subjected to 10 hours of total vascular occlusion showed a high incidence of necrosis when followed for 7 days following release of the vascular occlusion. Treatment with superoxide dismutase and salvia miltiorrhiza prior to the onset of reperfusion significantly enhanced island flap survival to 72.5% (P < 0.001) and to 64.2% (P < 0.05), respectively. The conclusions are: 1. Reperfusion for 10 hours following ischemia for 8 hours in the epigastric island flaps of the rats greatly exaggerated the original injury. 2. SOD and salvia miltiorrhiza may protect the flaps from such injury considerably and enhanced flap survival.

Amphipathic interactions of cannabinoids with membranes. A comparison between delta 8-THC and its O-methyl analog using differential scanning calorimetry, X-ray diffraction and solid state 2H-NMR

The effects of (-)-delta 8-tetrahydrocannabinol (delta 8-THC) and its biologically inactive O-methyl ether analog on model phospholipid membranes were studied using a combination of differential scanning calorimetry (DSC), small angle X-ray diffraction and solid state 2H-NMR. The focus of this work is on the amphipathic interactions of cannabinoids with membranes and the role of the free phenolic hydroxyl group which is the only structural difference between these two cannabinoids. Identically prepared aqueous multilamellar dispersions of phosphatidylcholines in the absence and presence of cannabinoids were used. The DSC thermograms and X-ray diffraction patterns of these preparations allowed us to detect the strikingly different manners in which these two cannabinoids affect the thermotropic properties and the thickness of the bilayer. In order study the effects of the cannabinoids on different regions of the bilayer, we used solid state 2H-NMR with four sets of model membranes from dipalmitoylphosphatidylcholine deuterated in different sites, viz., the choline trimethylammonium head group, or one of the following three groups in the acyl chains; the 2'-methylene, 7'-methylene, 16'-methyl groups. Analysis of quadrupolar splittings indicated that delta 8-THC resides near the bilayer interface and the inactive analog sinks deeper towards the hydrophobic region. The temperature dependence of the solid state 2H-NMR spectra showed that, during the bilayer phase transition, the disordering of the choline head groups is a separate event from the melting of the acyl chains, and that amphipathic interactions between delta 8-THC and the membrane separate these two events further apart in temperature. The inactive analog lacks the ability to induce such a perturbation.

Solid state 2H-NMR as a method for determining the orientation of cannabinoid analogs in membranes

In order to investigate the correlation between the pharmacological activities of cannabinoids and the geometric features of their interactions with membranes, we have calculated the molecular orientations of five analogs in model membrane bilayers. The studies involved the stereospecific 2H-labeling of each analog in different positions and the use of solid state 2H-NMR. The cannabinoids included in our study are (-)-delta 9-tetrahydrocannabinol (THC), (-)-delta 8-THC and its methylated ether analog (-)-O-methyl-delta 8-THC, as well as two hexahydrocannabinols (HHC) having an additional hydroxyl in the 11-position, (-)-11-OH-9 alpha-HHC and (-)-11-OH-9 beta-HHC. A new algorithm is used to circumvent the problem of deuterium quadrupolar splitting signs. The method has general applicability for calculating the orientation of a molecule in a anisotropic environment. Our calculations show that the biological inactive O-methyl-delta 8-THC orients with its long axis parallel to the lipid acyl chains, whereas the psychoactive cannabinoids assume "awkward" orientations in which the hydroxyl groups are pointing towards the bilayer interface, presumably to maximize the amphipathic interaction with the membrane. To produce their biological effects, cannabinoids may need to acquire an appropriate location and orientation in the membrane bilayer so that, through lateral diffusion, they can reach their sites of action and interact productively with these sites.

Small angle x-ray diffraction studies on the topography of cannabinoids in synaptic plasma membranes

In a previous publication, we have described in detail how we used small angle x-ray diffraction to determine the topography of (-)-delta 8-tetrahydrocannabinol (delta 8-THC) in dimyristoylphosphatidylcholine (DMPC) bilayers, and to deduce the conformation of the THC side chain by using the iodo-analog (5'-I-delta 8-THC) in the model membrane. We have now extended our studies to synaptic plasma membrane systems where the cannabinoids are believed to exert part of their pharmacological effects. Synaptic plasma membranes (SPM) were isolated from fresh bovine brains and delta 8-THC was incorporated into the membranes. By comparing the electron density profiles of drug free and drug-containing SPM preparations, we observed an electron density increase due to the presence of delta 8-THC in a region centered at 9.2 A from the terminal methyl groups of the membrane bilayer. In an attempt to dissect the effects of different membrane components on the topography of delta 8-THC, we carried out parallel experiments using membrane preparations from the synaptosomal membrane total lipid extract (TLX) as well as from bovine brain phosphatidyl choline extract (PCX) containing 30 mole percent cholesterol (Chol). Our results regarding the topography of delta 8-THC and 5'-I-delta 8-THC in these lipid membranes show that the TLX bilayer simulates the natural membrane environment very closely whereas in the PCX/Chol bilayer delta 8-THC resides at a location approximately 4 A closer to the membrane interface, similar to that found in our previous study using DMPC model membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

The perturbation of model membranes by (-)-delta 9-tetrahydrocannabinol. Studies using solid-state 2H- and 13C-NMR

The effects of (-)-delta 9-tetrahydrocannabinol (delta 9-THC) on model phospholipid membranes were studied using solid-state 2H and 13C nuclear magnetic resonance spectroscopy. Aqueous multilamellar dispersions of dipalmitoylphosphatidylcholine with specific 2H- and 13C-labels as endogenous probes at the C7, methylene and the carbonyl groups, respectively, of the sn-2 chain were used to study the conformational and dynamic properties of the bilayer as a function of temperature and drug concentration. The drug molecule decreases the phase transition temperature of the bilayer in a concentration dependent manner up to 20 molar percent when full saturation has occurred. The 2H spectra show that delta 9-THC broadens the phase transition during which the spectra acquire a characteristic shape of a two-component system exchanging at an intermediate rate (approximately 10(6) s-1) with some liquid crystalline features. Such spectra provide information related to the melting of the phospholipid chains. At intermediate temperatures, the 13C spectra show a gel-like and a liquid-crystalline-like exchanging components and provide information about a conformational change at the phospholipid glycerol backbone occurring at or near the pretransition. The spectral composition and rate of exchange are both dependent on drug concentration. We have carried out computer simulations of the 13C spectra and obtained conformational information related to the phase transition process in the bilayer from gel to liquid crystal. Our studies show that delta 9-THC has a stronger effect on the sn-2 carbonyl near the bilayer interface than on the lipid chains and serve to describe the membrane perturbing effects of cannabinoids in molecular terms.

Study of the topography of cannabinoids in model membranes using X-ray diffraction

Small-angle X-ray diffraction was used to determine the topography of (-)-delta 8-tetrahydrocannabinol in partially hydrated dimyristoylphosphatidylcholine bilayers. Electron density profiles of lipid bilayers in the presence and absence of the cannabinoid were calculated using Fourier transform. Step-function equivalent profiles were then constructed to obtain the absolute electron density scale. We have compared the electron density profiles of the above preparations to determine the location of the drug molecule in the bilayer. By using (-)-5'-iodo-delta 8-tetrahydrocannabinol in parallel experiments, we were also able to locate the iodine atom in the bilayer and deduce the conformation of the cannabinoid side alkyl chain. All comparisons were made between different preparations having the same mesomorphic form and total period repeat distance. To achieve this, we have carried out X-ray diffraction experiments at various temperatures to cover the different mesomorphic phases and combined our data with the corresponding results from differential scanning calorimetry. Based on the results of this work and previous data on the orientation of the cannabinoid in model membranes, we concluded that the phenolic hydroxy group of the drug molecule exists near the carbonyl groups of DMPC and that the average position of the iodine atom is approx. 5.5 A from the center (terminal methyl region) of the DMPC bilayer. This requires the cannabinoid side-chain to assume an orientation parallel to the bilayer chains.

The orientation of (-)-delta 9-tetrahydrocannabinol in DPPC bilayers as determined from solid-state 2H-NMR

The orientation of the motional axis of (-)-delta 9-tetrahydrocannabinol in dipalmitoylphosphatidylcholine model membrane was calculated from the 2H quadrupolar splittings (delta nu Q) of individual deuterons strategically located on the cannabinoid tricyclic component. The molecule assumes an orientation in which its long axis is nearly perpendicular to the phospholipid chains and its most ordered axis is almost in the plane of the aromatic ring. This 'awkward' cannabinoid orientation in the membrane presumably occurs in order to allow the phenolic hydroxyl group to direct itself towards the polar bilayer interface.

[Clinical observation on hypercortisolism treated with amino-glutethimide]

We reported the clinical results in 13 cases of hypercortisolism treated with amino-glutethimide (AG), which was developed by Tiantsin Research Institute of Medical Industry. Of the thirteen cases nine were confirmed by surgery and histology, and the others were diagnosed clinically. Clinical improvements have been achieved in ten of the thirteen cases over a therapeutic course of 8 to 12 wk with a daily dosage of 1.0 to 2.0 g of AG. Plasma and urinary corticosteroids, as well as plasma testosterone levels were significantly decreased after one-month treatment followed, however, by somewhat return and fluctuation. The high levels of blood glucose and serum insulin were declined after therapy consistent with the decrement of corticoids. Serum potassium levels in hypokalemic patients returned to normal after one month of therapy. Radial bone mineral contents in patients with low bone density returned or closed to normal after three-month treatment. The main side effects of AG are anorexia, nausea, drowsy, tierdness, skin rashes, etc, which are mild and transient. Adrenal hypofunction was seen in one case after treatment.

Induction of sister chromatid exchanges in human diploid fibroblasts by mutagens with and without rat liver microsomal activation

The frequency of sister chromatid exchange (SCE) in WI-38 cells was estimated by the 5-bromodeoxyuridine (BrdUrd)-dye technique after one hour's exposure to cyclophosphamide (CY), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 4-nitroquinoline-1-oxide (4NQO), and maleic hydrazide (MH) with and without the addition of rat liver microsomal suspension (S-9) fraction with cofactors (S-9 mix). CY at concentrations from 1 x 10(-5) M to 1 x 10(-3) M with S-9 mix increased the number of SCEs per cell in a dose-dependent manner. Without S-9 mix, CY at concentrations below 1 x 10(-3) M failed to produce more SCEs than the controls. MNNG at 1 x 10(-8) M and 4NQO at 1 x 10(-7) M without S-9 produced significant increases in SCEs per cell. Addition of S-9 during treatment slightly decreased the effects of MNNG and 4NQO in the formation of SCEs. MH was tested at pH 6.4 and pH 7.6. At pH 7.6, MH at 1 x 10(-3)M without S-9 mix inhibited cell multiplication, but did not cause a significant increase of SCEs per cell. There were no interactions between MH (2 x 10(-4) M) and S-9 mix nor between MH and the pH levels tested. These results indicate that in the presence of metabolic activation, SCE formation in human diploid fibroblasts in vitro may be used as a potential assay for mutagenicity.

Specific chromosome changes associated with rabbit cell lines cultured in vitro

Thirty-three rabbit cell lines were established from various fetal tissues of the inbred strain III of the New Zealand rabbit (Oryctolagus cuniculus). None of these lines exhibited senescence during a growth period of more than 2 years. Karyologic studies of most cell lines at 10 to 20 cell-passage intervals revealed that the karyotype stability of the rabbit cells in vitro was correlated with the organs from which the cell lines were derived. Thus, lines derived from cornea, spleen, and kidney tissues usually contained high frequencies of polyploidy in their early passages, whereas most of those derived from lung and skin were found to retain the normal diploid karyotype for much longer periods of time. One line derived from fetal lung tissue, designated Lung 16, remained diploid up to 100 passages. In late passages of the majority of all the lines studied, the cells became pseudodiploid, hyperdiploid, or polyploid. Among the pseudodiploid and the hyperdiploid cell lines, the chromosomal changes followed three basic patterns: (1) a gain of one or more telocentric chromosomes; (2) a loss of one telocentric chromosome plus a metacentric marker chromosome (M); or (3) a gain of a long telocentric marker chromosome with or without changes in the number of telocentric D chromosomes. By the G-banding technique, the telocentric chromosome involved in these three patterns was identified as the D-group chromosome 18 and the M marker chromosome as an isochromosome of 18. These results suggest that chromosomal rearrangement in rabbit cells involving trisomy of 18 may be responsible for the longevity of these cell lines cultured in vitro.

The development of rabbit diploid cell lines

The authors describe briefly studies on the development of diploid cell lines from fetal tissues (origin: four inbred rabbits). Some lines have been maintained in continuous serial culture for over three years. The Lung 16 may represent a qualifying rabbit diploid cell line when used between cell passages 48 and 100; during this period it has shown a minimum deviation from the normal diploid rabbit karyotype; it supports the growth of rubella virus, is non-tumorigenic and might be useful as a substrate for human vaccine.