[Corticosteroid allergy: a paradox?]

Although corticosteroids have both antiinflammatory and immunosuppressive effects, they can occasionally induce allergic reactions when given topically or systemically. Since cross-reactions exist within the corticosteroid groups A-D, the corticosteroid should be changed to another group whenever suspicion arises. It makes sense to render an allergy-related diagnosis early so that a suitable corticosteroid is ready for an emergency.

Molecular mode-coupling theory applied to a liquid of diatomic molecules

We study the molecular mode-coupling theory for a liquid of diatomic molecules. The equations for the critical tensorial nonergodicity parameters F(m)(ll('))(q) and the critical amplitudes of the beta relaxation H(m)(ll('))(q) are solved up to a cutoff l(co)=2 without any further approximations. Here l,m are indices of spherical harmonics. Contrary to previous studies, where additional approximations were applied, we find in agreement with simulations that all molecular degrees of freedom vitrify at a single temperature T(c). The theoretical results for the nonergodicity parameters and the critical amplitudes are compared with those from simulations. The qualitative agreement is good for all molecular degrees of freedom. To study the influence of the cutoff on the nonergodicity parameter, we also calculate the nonergodicity parameters for an upper cutoff l(co)=4. In addition, we also propose a method for the calculation of the critical nonergodicity parameter from the liquid side of transition.

Efficiency of continuous positive airway pressure versus theophylline therapy in sleep apnea: comparative sleep laboratory studies on objective and subjective sleep and awakening quality

Sleep apnea is the most common sleep-related breathing disorder characterized by repetitive episodes of hypoxemia. Therapies include behavioral, surgical, orthodontic, pneumological, and pharmacological interventions. The aim of the present study was to compare the efficiency of pneumological therapy by nasal continuous positive airway pressure (CPAP) versus a pharmacological approach with theophylline (Respicur retard(R) 400 mg) on respiratory variables as well as objective and subjective sleep and awakening quality in patients with moderate sleep apnea measured by polysomnography and psychometry. Under CPAP therapy all respiratory variables improved and normalized, while under theophylline only the apnea-hypopnea index and the desaturation index improved but still did not return to normal values. Regarding sleep initiation and maintenance, CPAP therapy prolonged sleep latency and reduced movement time, while patients treated with theophylline showed reduced total sleep period, total sleep time and sleep efficiency. Sleep architecture demonstrated an increase in deep sleep and REM stages under CPAP therapy, and remained unchanged under theophylline. Concerning subjective sleep and awakening quality, both treatments improved well-being in the morning. Regarding objective awakening quality, reaction time performance was improved in both groups. In conclusion, CPAP treatment is more effective than theophylline regarding respiratory variables as well as the normalization of sleep maintenance and sleep architecture in sleep apnea patients.

Autoradiographic distribution of mu-, delta- and kappa 1-opioid stimulated [35S]guanylyl-5'-O-(gamma-thio)-triphosphate binding in human frontal cortex and cerebellum

Opioid receptors are known to couple to G-proteins and to inhibit adenylyl cyclase. Receptor activation of G-proteins can be measured by agonist-stimulated [35S]guanylyl-5'-O-(gamma-thio)-triphosphate (GTP gamma S-) binding in brain sections to localize neuroanatomically functional coupling of receptors to intracellular signal transduction mechanisms. In the present study the selective mu-, delta- and kappa 1-opioid agonists DAMGO ([D-Ala2,N-Me-Phe4, Gly-ol5]-enkephalin), DPDPE ([D-Pen2,5]-enkephalin) and enadoline (CI-977) were used to stimulate [35S]GTP gamma S-binding in human brain sections of frontal cortex and cerebellum. In human frontal cortex mu- and delta- opioid stimulated [35S]GTP gamma S-binding was evenly distributed throughout the gray matter, while kappa(1)-opioid stimulated [35S]GTP gamma S-binding was detected predominantly in lamina V and VI. In the cerebellar cortex stimulated [35S]GTP gamma S-binding revealed functional coupling of mu- and kappa 1-opioid receptors in the molecular layer.

Human anti-HIV-1 tat sFv intrabodies for gene therapy of advanced HIV-1-infection and AIDS

The early successes of highly active anti-retroviral therapies (HAART) for the treatment of HIV-1-infection and AIDS have raised the question as to whether there is a legitimate role for gene therapy in the treatment of this chronic infectious disease. However, in many patients the profound suppression of viral replication is short lived, particularly if patients have been treated with sequential monotherapies in the past, have been infected with a highly drug resistant isolate of HIV-1, or have temporarily discontinued therapy as a "holiday" or because of drug intolerance. In addition, life-long adherence to maintenance HAART will probably be required even in responding patients with undetectable viremia because of the reservoirs of latently infected cells that can persist for years. Gene therapy through the introduction of anti-retroviral "resistance" genes into CD4(+) T cells is one approach that could give long term protection to these HIV-1 susceptible cells in vivo. We have explored this approach by developing intrabodies to the critical HIV-1 transactivator protein, Tat that is absolutely required for HIV-1 replication. This provocative treatment approach, that will be tested in a clinical gene therapy trial, sets the groundwork for determining if anti-Tat intrabody gene therapy together with HAART can provide a treatment strategy for the immune reconstitution of HIV-1-infected patients with advanced disease.

Elements of the kallikrein-kinin system are present in rat seminiferous epithelium

Peptide hormones are involved in the paracrine regulation of several physiological processes. A possible function of the kallikrein-kinin system (KKS) in mammalian reproduction has been discussed. To evaluate its putative role in spermatogenesis, we searched for components of the KKS (kallikrein, kininases, kinin receptor) in the rat testis. Specific immunostaining demonstrated that the kininogenase tissue kallikrein was present in round and elongated spermatids. Leydig cells, Sertoli cells, peritubular cells, spermatogonia and spermatocytes were not stained. Bradykinin in the supernatant of Sertoli cell cultures was effectively degraded. The resulting metabolites were analysed by high-performance liquid chromatography (HPLC). Specific protease inhibition in the degrading experiments confirmed the occurrence of several metalloproteases on Sertoli cell membranes, including neutral metalloendopeptidases (NEP 24.11 and NEP 24.15), kininase type II (angiotensin converting enzyme, ACE), and kininase type I (metallocarboxypeptidase). Northern blots hybridized with a bradykinin B2 receptor probe showed the presence of B2 receptor mRNA in testis homogenate and Sertoli cell extract. All components of the kallikrein-kinin system are present within the seminiferous epithelium of the rat. Therefore, this paracrine peptide system may play a role in the regulation of Sertoli cell function or in the Sertoli cell-germ cell crosstalk.

Effects of chronic alcohol consumption on the expression of different NR1 splice variants in the brain of AA and ANA lines of rats

Following chronic alcohol treatment alterations in N-methyl-D-aspartate receptor subunit 1 and 2 (NR1 and NR2), mRNA and protein levels have been reported. The NR1 gene undergoes alternative RNA splicing, resulting in eight splice variants, which were shown to differ in their sensitivity to alcohol. Here, we studied mRNA and protein levels of NR1 splice variants in alcohol-preferring (AA) and alcohol-nonpreferring (ANA) rat lines under basal conditions (alcohol-naive), and following chronic alcohol consumption. mRNA levels of three NR1 splice variants (NR1-1, NR1-2, NR1-4), and the protein levels of NR1 (NR1-1/NR1-2), and of NR1 alternative C-terminus (NR1-3/NR1-4) were determined in the hippocampus and nucleus accumbens by competitive RT-PCR and Western blot analysis, respectively. No significant differences in NR1 mRNA, or protein levels were found in the nucleus accumbens between the two rat lines under basal conditions, or following chronic alcohol consumption. In the hippocampus of alcohol-naive rats, the NR1-4 mRNA content was significantly higher in ANA compared to AA rats, however, no significant difference could be detected at the protein level. Following chronic alcohol consumption, the protein level of the NR1 alternative C-terminus (NR1-3/NR1-4) was significantly higher in AA rats compared to the corresponding control. Taken together, these results suggest: (i) brain site-specific alterations in NMDA receptor subunit composition occur following chronic alcohol consumption. (ii) In the hippocampus, NR1 splice variant mRNA levels differ between AA and ANA rats. (iii) The mRNA levels and protein levels of NR1 splice variants are differentially affected by chronic alcohol consumption.

Does shortening matter after clavicular fractures?

Healing of clavicular fractures with shortening of 15 mm or more has been associated with poor function and open reduction and internal fixation has been recommended as the appropriate initial treatment. We studied 41 patients at least three months after clavicular fracture. Clavicular shortening was calculated and shoulder function was assessed using the Constant Scoring method. Although three patients with shortening of 1.5 cm or more had low scores, this could be attributed to other factors. We could not demonstrate any relationship between clavicular shortening and shoulder function.

Accurate quantification of the mRNA of NMDAR1 splice variants measured by competitive RT-PCR

N-methyl-D-aspartate receptors (NMDAR) belong to the subclass of ionotropic glutamate receptors and are widely distributed in the vertebrate brain. Molecular cloning has revealed the existence of six NMDAR subunits: one NMDAR1 (NR1), four different NMDAR2 (NR2A-D) and one NMDAR3A (NR3A). Alternative splicing of the single NR1 gene generates eight isoforms with distinct functional properties [M. Hollmann, J. Boulter, C. Maron, L. Beasley, J. Sullivan, G. Pecht, S. Heinemann, Zinc potentiates agonist-induced currents at certain splice variants of the NMDA receptor, Neuron 10 (1993) 943-954 [8]; R.S. Zukin, M.V.L. Bennett, Alternatively spliced isoforms of the NMDAR1 receptor subunit, TiNS 18 (1995) 306-313 [20]]. Despite the progress made in the functional analysis of NMDARs the molecular architecture of this receptor remains to be elucidated. In situ hybridization studies have already indicated that splicing of the NR1 gene is regionally regulated in the rodent brain, which may contribute to functional diversity of NMDARs in distinct brain areas [D.J. Laurie, P.H. Seeburg, Regional and developmental heterogeneity in splicing of the rat brain NMDAR1 mRNA, J. Neurosci. 14 (1994) 3180-3194 [10]; D.G. Standaert, C.M. Testa, A.B. Young, J.B. Penney Jr., Organization of N-methyl-D-aspartate glutamate receptor gene expression in the basal ganglia of the rat, J. Comp. Neurology 343 (1994) 1-16 [18]; M. Hollmann, S. Heinemann, Cloned glutamate receptors, Ann. Rev. Neurosci. 17 (1994) 31-108 [9]]. Since in situ hybridization techniques do not allow accurate quantification of distinct NR1 splice variants and are also very time-consuming, an accurate and sensitive competitive RT-PCR assay was developed. This method was then used to study the distribution of three NR1 splice variants in the rat brain, and the results are compared with former in situ hybridization studies.

Gene transfer into fetal baboon hematopoietic progenitor cells

We studied hematopoietic progenitors from fetal baboon blood, marrow, and liver at four time points (125, 140, 160, and 175 days) during the third trimester (gestation approximately 180 days) to determine if fetal baboons might be an appropriate model for in utero gene therapy of hematopoietic stem cells (HSCs). Cells were studied for expression of CD34, CD33, CD38, and HLA-DR, for progenitor content in colony-forming cell assays, and for susceptibility of CD34+ progenitors to retrovirus-mediated gene transfer. Throughout the third trimester, the frequency of CD34+ progenitors in blood and marrow appears to remain unchanged at approximately 0.6 and 5.0%, respectively. In liver, progenitors progressively decrease to undetectable levels by day 175. The proportion of fetal baboon bone marrow and liver CD34+ cells expressing CD38 and HLA-DR appears to increase with increasing fetal age, similar to changes reported for human cord blood CD34+ cells. In fetal baboon blood the proportion of CD34+ cells expressing CD33 appears to decrease with increasing gestational age, also similar to changes reported for human cord blood cells. Progenitors from human cord blood and baboon fetal tissues were similarly susceptible to transduction by the gibbon ape leukemia pseudotyped retroviral vector LAPSN(PG13) containing the genes for human placental alkaline phosphatase (AP) and the bacterial neomycin phosphotransferase (neo). Fetal baboon and human hematopoietic progenitor cells undergo similar phenotypic changes during the third trimester of fetal development and are similarly susceptible to retrovirus-mediated gene transfer. The fetal baboon may be a model in which approaches to mobilization and gene transfer into fetal HSCs can be studied.

Mechanism of peptide-induced mast cell degranulation. Translocation and patch-clamp studies

Substance P and other polycationic peptides are thought to stimulate mast cell degranulation via direct activation of G proteins. We investigated the ability of extracellularly applied substance P to translocate into mast cells and the ability of intracellularly applied substance P to stimulate degranulation. In addition, we studied by reverse transcription--PCR whether substance P-specific receptors are present in the mast cell membrane. To study translocation, a biologically active and enzymatically stable fluorescent analogue of substance P was synthesized. A rapid, substance P receptor- and energy-independent uptake of this peptide into pertussis toxin-treated and -untreated mast cells was demonstrated using confocal laser scanning microscopy. The peptide was shown to localize preferentially on or inside the mast cell granules using electron microscopic autoradiography with 125I-labeled all-D substance P and 3H-labeled substance P. Cell membrane capacitance measurements using the patch-clamp technique demonstrated that intracellularly applied substance P induced calcium transients and activated mast cell exocytosis with a time delay that depended on peptide concentration (delay of 100-500 s at concentrations of substance P from 50 to 5 microM). Degranulation in response to intracellularly applied substance P was inhibited by GDPbetaS and pertussis toxin, suggesting that substance P acts via G protein activation. These results support the recently proposed model of a receptor-independent mechanism of peptide-induced mast cell degranulation, which assumes a direct interaction of peptides with G protein alpha subunits subsequent to their translocation across the plasma membrane.

Effect of ethanol drinking on the gene expression of opioid receptors, enkephalinase, and angiotensin-converting enzyme in two inbred mice strains

There is convincing evidence that genetic factors contribute to the predisposition to alcoholism. In this respect, alcohol-preferring (like C57BL/6 mice) and alcohol-avoiding lines (like DBA/2 mice) of animals served as models in the search for neurobiological substrates of excessive ethanol consumption. One of the systems that is thought to be associated with the incidence of alcoholism is the endogenous opioid system. In the first experiment, basal mRNA levels of mu- and delta-opioid receptors, and of opioid-degrading enzymes enkephalinase (neutral endopeptidase 24.11; NEP) and angiotensin-converting enzyme (ACE) in the brain regions of C57BL/6 and DBA/2 mice did not reveal genetically determined differences in these parameters between the two strains. Furthermore, in the brain regions studied, the corresponding enzyme activities of NEP and ACE did not differ significantly between the lines of mice, except for a higher NEP activity in the striatum and olfactory bulb of DBA/2 mice (p < 0.01). In the second experiment, C57BL/6 and DBA/2 mice were offered a free choice between water and 10% ethanol solution for 4 weeks and were killed thereafter; from another group, ethanol was removed for 3 days and from a third group ethanol was removed for 3 weeks before killing. In the striatum, a highly significant increase in the ACE mRNA amount was detected after 3 weeks of removal of ethanol in C57BL/6 mice, whereas in DBA/2 mice the delta-opioid receptor mRNA level was increased at this time when compared with the corresponding ethanol treatment group. The most striking changes were seen in the hypothalamus, where mu-opioid receptor, ACE, and NEP mRNA amounts markedly decreased after ethanol treatment in both strains. Thus, chronic ethanol intake caused significant changes in the gene expression of distinct components of the endogenous opioid system. These findings further underline an involvement of the opioid system in the effects of ethanol.

Inhibition of corticotropin releasing factor (CRF)-induced adrenocorticotropin (ACTH) secretion in pituitary corticotropic cells by substance P

Substance P (SP) is one of the three distinct peptides of tachykinin system which possess a common spectrum of biological activities including a modulation of stress. It is assumed that the anterior pituitary is one possible target of SP in attenuation the stress response. Therefore the interaction between the hypothalamic stress hormone corticotropin releasing factor (CRF) and SP was investigated in AtT20/D16v-cells, a cellular model derived from a pituitary tumor. CRF stimulates the release of ACTH from AtT20/D16v cells in a concentration dependent manner. SP (1 microM) was able to abolish the CRF (100 nM)-induced ACTH release. In the same way SP inhibited the CRF-induced accumulation of cyclic adenosine monophosphate (cAMP), indicating that SP influenced the signal transduction pathway of CRF receptor activation. Thus, a direct inhibition of the CRF-mediated stress response by SP at the level of anterior pituitary seems to be likely.

Normoxic cardiopulmonary bypass reduces oxidative myocardial damage and nitric oxide during cardiac operations in the adult

OBJECTIVE

Hyperoxic cardiopulmonary bypass is widely used during cardiac operations in the adult. This management may cause oxygenation injury induced by oxygen-derived free radicals and nitric oxide. Oxidative damage may be significantly limited by maintaining a more physiologic oxygen tension strategy (normoxic cardiopulmonary bypass).

METHODS

During elective coronary artery bypass grafting, 40 consecutive patients underwent either hyperoxic (oxygen tension = 400 mm Hg) or normoxic (oxygen tension = 140 mm Hg) cardiopulmonary bypass. At the beginning and the end of bypass this study assessed polymorphonuclear leukocyte elastase, nitrate, creatine kinase, and lactic dehydrogenase, antioxidant levels, and malondialdehyde in coronary sinus blood. Cardiac index was measured before and after cardiopulmonary bypass.

RESULTS

There was no difference between groups with regard to age, sex, severity of disease, ejection fraction, number of grafts, duration of cardiopulmonary bypass, or ischemic time. Hyperoxic bypass resulted in higher levels of polymorphonuclear leukocyte elastase (377 +/- 34 vs 171 +/- 32 ng/ml, p = 0.0001), creatine kinase 672 +/- 130 vs 293 +/- 21 U/L, p = 0.002), lactic dehydrogenase (553 +/- 48 vs 301 +/- 12 U/L, p = 0.003), antioxidants (1.97 +/- 0.10 vs 1.41 +/- 0.11 mmol/L, p = 0.01), malondialdehyde (1.36 +/- 0.1 micromol/L,p = 0.005), and nitrate (19.3 +/- 2.9 vs 10.1 +/- 2.1 micromol/L, p = 0.002), as well as reduction in lung vital capacity (66% +/- 2% vs 81% +/- 1%,p = 0.01) and forced 1-second expiratory volume (63% +/- 10% vs 93% +/- 4%, p = 0.005) compared with normoxic management. Cardiac index after cardiopulmonary bypass at low filling pressure was similar between groups (3.1 +/- 0.2 vs 3.3 +/- 0.3 L/min per square meter). [Data are mean +/- standard error (analysis of variance), with p values compared with an oxygen tension of 400 mm Hg.]

CONCLUSIONS

Hyperoxic cardiopulmonary bypass during cardiac operations in adults results in oxidative myocardial damage related to oxygen-derived free radicals and nitric oxide. These adverse effects can be markedly limited by reduced oxygen tension management. The concept of normoxic cardiopulmonary bypass may be applied to surgical advantage during cardiac operations.

Differences in the kappa opioid receptor mRNA content in distinct brain regions of two inbred mice strains

The inbred C57BL/6 mouse strain is known to prefer an ethanol solution in a two-bottle choice procedure, whereas the inbred DBA/2 mouse strain avoids drinking ethanol in this paradigm. The genetic basis of this behavior is still unclear but the endogenous opioid system is one of the factors thought to be involved. Therefore, we were interested to see if there are basal differences between the two lines of mice in the kappa opioid receptor (kappa OR) mRNA content in different brain regions. Because of the low expression level of this gene and the limited amount of tissue we developed a sensitive competitive reverse transcription-polymerase chain reaction (RT-PCR) assay for evaluation of levels of kappa OR mRNA in brain tissue. In septum and hypothalamus the DBA/2 mice showed a significantly higher basal level of kappa OR mRNA than did C57BL/6 mice. It is suggested that a difference in basal amount of kappa OR mRNA among these strains could lead to differences in kappa OR activity and subsequently to variations between the strains in distinct behaviors such as in ethanol preference.

Gene expression and activity of specific opioid-degrading enzymes in different brain regions of the AA and ANA lines of rats

There is increasing evidence that alcoholism runs in families suggesting that genetic factors may play a role. In support of this hypothesis, the alcohol-preferring (AA) and the alcohol-avoiding (ANA) rat lines have been developed through selective outbreeding. Numerous studies indicate that the endogenous opioid system may be involved in controlling ethanol consumption. Changes in opioid peptides and opioid receptors have been described after ethanol intake. But, the influence of ethanol on peptidolytic degradation of opioid peptides has been largely ignored, although the peptidase-mediated metabolism of neuropeptides is known as an important regulatory site of peptidergic transmission. Neutral endopeptidase 24.11 (NEP) and angiotensin-converting enzyme (ACE) degrade neuropeptides, including enkephalin and are expressed in the brain. Furthermore, a good correspondence between the regional distribution of NEP and opioid receptors in rat brain has already been reported pointing to a possible role of NEP in regulating opioid peptides. For both enzymes studied, the gene expression pattern was found to be in good agreement with the corresponding enzyme activities in the brain regions investigated, showing the highest levels for both specific mRNAs and enzyme activities in the striatum. Differences in both measured parameters were detected in distinct brain regions of AA and ANA rats. Furthermore, in some brain regions discrepancies between ACE and NEP mRNA levels and the corresponding enzyme activities were observed. For example, in olfactory bulb and striatum such discrepancies were found for both enzymes studied. In tegmentum/colliculi a higher NEP gene expression in AA rats was associated with a higher NEP enzyme activity compared to the amounts found in ANA rats.

Effects of long term treatment with corticotropin releasing factor on corticotropic tumor cells in vitro

hCRF inhibits proliferation of corticotropic tumor cells cultivated in serum-reduced medium via interaction with CRF-receptors. This effect was attenuated by the specific antagonist hCRF (9-41), but not by a variety of substances which are inhibitors of cAMP production or cAMP-dependent kinases, suggesting that the effect was not mediated via cAMP. The growth inhibiting effect of hCRH was developed after 4 h incubation, a longer hCRF treatment did not change the effect observed after 4 h. Simultaneously, after hCRF treatment for 4 days the cells were insensitive for ACTH release by hCRF stimulation despite of an increase in the number of secretory granules. The results show that the inhibition of proliferation of pituitary tumor cells by hCRF seems to be a rapid receptor-mediated process connected with morphological changes, but not mediated via activation of adenylate cyclase.

Quantification of proopiomelanocortin mRNA in peripheral lymphocytes of alcoholics

Recent studies indicate the production of adrenocorticotropic hormone (ACTH) by human mononuclear leucocytes constitutively or in response to hypothalamic factors and interferon inducers. These results have led to the proposal that the control mechanisms for the proopiomelanocortin (POMC) gene in lymphocytes may be similar to that of pituitary cells. After chronic ethanol treatment, changes in the pituitary POMC mRNA in rats have been reported, but so far nothing is known about changes in the POMC gene expression in lymphocytes under these conditions. Therefore, the expression of the POMC gene was investigated in human peripheral lymphocytes in both volunteers and alcoholics. POMC mRNA levels in these cells were significantly increased in alcoholics, with one alcoholic showing an even more than five times higher POMC mRNA level compared to the other patients. After detoxification, a significant decrease in the POMC mRNA of alcoholic patients was observed, except in the one with the extremely elevated POMC mRNA level, where the opposite occurred. An influence of chronic ethanol ingestion on POMC gene expression in lymphocytes could be assumed. The observed changes seem to be correlated with ethanol intake, because the elevated POMC mRNA amounts found in lymphocytes of alcoholics after admission to the hospital were already declining after the detoxification period.

Gene transfer into marrow repopulating cells: comparison between amphotropic and gibbon ape leukemia virus pseudotyped retroviral vectors in a competitive repopulation assay in baboons

Many diseases might be treated by gene therapy targeted to the hematopoietic system, but low rates of gene transfer achieved in humans and large animals have limited the application of this technique. We have developed a competitive hematopoietic repopulation assay in baboons to evaluate methods for improving gene transfer and have used this method to compare gene transfer rates for retroviral vectors having an envelope protein (pseudotype) from amphotropic murine retrovirus with similar vectors having an envelope protein derived from gibbon ape leukemia virus (GALV). We hypothesized that vectors with a GALV pseudotype might perform better based on our previous work with cultured human hematopoietic cells. CD34(+) marrow cells from each of four untreated baboons were divided into two equal portions that were cocultivated for 48 hours with packaging cells producing equivalent titers of either amphotropic or GALV pseudotyped vectors containing the neo gene. The vectors contained small sequence differences to allow differentiation of cells genetically marked by the different vectors. Nonadherent and adherent cells from the cultures were infused into animals after they received a myeloablative dose of total body irradiation. Polymerase chain reaction (PCR) analysis for neo gene-specific sequences in colony-forming unit-granulocyte-macrophage from cell populations used for transplant showed gene transfer rates of 2.7%, 7.1%, <15%, and 3.9% with the amphotropic vectors and 7.1%, 11.3%, <15%, and 26.4% with the GALV pseudotyped vector. PCR analysis of peripheral blood and marrow cells after engraftment showed the neo gene to be present in all four animals analyzed at levels between 0.1% and 5%. Overall gene transfer efficiency was higher with the GALVpseudotyped vector than with the amphotropic vectors. Southern blot analysis in one animal confirmed a gene transfer efficiency of between 1% and 5%. The higher gene transfer efficiency with the GALV-pseudotyped vector correlated with higher levels of GALV receptor RNA compared with the amphotropic receptor in CD34(+) hematopoietic cells. These results show that GALV-pseudotyped vectors are capable of transducing baboon marrow repopulating cells and may allow more efficient gene transfer rates for human gene therapy directed at hematopoietic cells. In addition, our data show considerable differences in gene transfer efficiency between individual baboons, suggesting that a competitive repopulation assay will be critical for evaluation of methods designed to improve gene transfer into hematopoietic stem cells.

Survival-promoting activity of inhibitors of cyclin-dependent kinases on primary neurons correlates with inhibition of c-Jun kinase-1

Cyclin-dependent kinases and mitogen-activated protein kinases have been implicated in the regulation of cellular survival and apoptosis. We tested the effect of two mitogen-activated/cyclin-dependent kinase inhibitors, olomoucine and butyrolactone I, on the in vitro survival of chick embryonic neurons. Sensory, sympathetic, and ciliary neurons, when prepared at their respective time point of programmed cell death, could be rescued from apoptosis by both inhibitors in a dose-dependent fashion. In contrast, dividing sympathetic precursors underwent apoptosis when treated with olomoucine, but not butyrolactone I, at the same range of concentration. With similar potency, olomoucine and butyrolactone I inhibited immunocomplex c-Jun kinase activity. Both substances inhibited neurite outgrowth in a dose-dependent manner; developmentally younger neurons were more sensitive to this effect than older ones. These results suggest that certain mitogen-activated/cyclin-dependent kinases associated with cell division in neuronal precursors (i) may become essential components of the apoptotic machinery by the time neurons reach their phase of naturally occurring cell death and (ii) may be necessary for neurite outgrowth during development.

Normal immunologic response to a neoantigen, bacteriophage phiX-174, in baboons with long-term lymphohematopoietic reconstitution from highly purified CD34+ Lin- allogeneic marrow cells

The CD34 antigen is thought to be expressed by hematopoietic stem cells in adult humans and nonhuman primates. We present data that baboons transplanted with highly purified allogeneic CD34+ marrow cells devoid of detectable mature and immature T and B lymphocytes and myeloid cells, isolated from sex-mismatched mixed lymphocyte culture (MLC) nonreactive siblings, have maintained stable lymphohematopoietic engraftment with donor cells for greater than 4.9, greater than 6.0, and 5.0 years. Cytogenetic analysis of unfractionated marrow and peripheral blood cells at multiple time points after transplantation show virtually all donor cells in two animals and stable mixed chimerism in the third. We used polymerase chain reaction to show that colony-forming unit-granulocyte-macrophage, burst-forming unit-erythroid, and high proliferative potential colony-forming cells (HPP-CFC) were virtually all of donor origin in two animals and present at lower levels in the stable mixed chimera. CD20+ B-lymphoblastoid cell lines derived by Herpesvirus Papio transformation of peripheral blood cells were virtually all donor in two animals and 50% donor in the mixed chimera. CD4+ and CD8+ T cells and neutrophils purified from the peripheral blood of the two female animals also were all donor-derived. To assess immunologic function after transplantation, we immunized the three long-term chimeric animals and two normal control animals with bacteriophage phiX-174, a neoantigen that requires the interaction of antigen-presenting cells, T lymphocytes, and B lymphocytes to mount a normal antibody response. Experimental and control animals, when immunized with bacteriophage, had similar serum Ig levels. The experimental and control animals generated similar titers of antibacteriophage antibodies after primary and secondary immunizations with evidence of amplification and class switching. These findings further support the hypothesis that the CD34+ antigen is expressed on hematopoietic stem cells that can mediate stable long-term lymphohematopoiesis in vivo and, importantly, that normal immunologic function can be reconstituted in vivo after transplantation of the highly purified CD34+ Lin- cells alone.

Integrative erectile biology: the role of signal transduction and cell-to-cell communication in coordinating corporal smooth muscle tone and penile erection

The contractility of corporal smooth muscle plays a critical role in the entire erectile process in man. Moreover, in the absence of severe vascular disease, or congenital or other structural abnormalities/malformations, relaxation of the corporal smooth muscle is both necessary and sufficient to elicit a sustained erection. As such, understanding the initiation, maintenance and modulation of corporal smooth muscle tone is an absolute prerequisite to the improved understanding, diagnosis and treatment of erectile dysfunction. Despite this fact, identification of both the precise mechanistic basis by which endogenous and exogenous vasomodulators exert their effects on individual corporal smooth muscle cells, and moreover, the process by which these signals are spread among the diverse array of parenchymal cells in the paired corpora, remains somewhat of a physiological enigma. Therefore, the goal of this report is two-fold: first, to review current knowledge of the regulation of corporal smooth muscle tone at the cellular and molecular level; and second, to outline a cogent explanation for the rapid and syncytial integration of the effects of diverse stimuli among corporal smooth muscle cells in the human penis.

A novel SOD1 mutation in an Austrian family with amyotrophic lateral sclerosis

We report on an Austrian pedigree with autosomal dominant amyotrophic lateral sclerosis (ALS), diagnosed in six patients from two generations. The only surviving clinically affected family member was examined in our ALS clinic. Historical information on other affected individuals was obtained from knowledgeable family members. The mean +/- S.D. age of onset of the disease was 54 +/- 6.9 years, with a range of 43-66 years. The duration of the index patient's disease until death was 8 months. Using single strand conformational polymorphism (SSCP) analysis, we studied the index patient's exons 1, 2 and 4 of the Cu/Zn superoxide dismutase gene (SOD1) on chromosome 21. A variant banding pattern was observed for exon 1. Sequencing studies showed a previously undescribed T to A missense mutation at position 8 in exon 1 of the SOD1 gene. This mutation results in the elimination of an Eco57I restriction site. Whereas the index patient was heterozygous for this restriction site, 50 unrelated healthy controls and an unaffected brother were not. The mutation lies in a region involved in dimer contact in the three-dimensional structure of the SOD1 protein. This region comprises other known sites for ALS-causing mutations.

Recombinant human ligand for MPL, megakaryocyte growth and development factor (MGDF), stimulates thrombopoiesis in vivo in normal and myelosuppressed baboons

Megakaryocyte growth and development factor (MGDF) is a ligand for c-mpl and a member of the hematopoietic growth factor superfamily. Recombinant murine MGDF specifically stimulates thrombopoiesis in mice. Recombinant human (rHu) MGDF stimulates megakaryocytic differentiation of baboon CD34+ marrow cells in vitro. Therefore, we determined the in vivo biological effects of rHuMGDF administered to normal baboons in the absence and presence of myelosuppression with 5-fluorouracil (5-FU). rHuMGDF was administered to normal baboons as a single s.c. injection at doses of 1, 10, 25 and 50 micrograms/kg/day for 10 days and, as a control, heat-inactivated MGDF was administered at a dose of 10 micrograms/kg/day. Platelet counts were markedly increased in all animals administered native rHuMGDF but not in animals given heat-inactivated rHuMGDF. Platelet counts began to increase between three and six days after starting rHuMGDF administration and the maximum average increases were 1.7-, 3.4-, 5.1- and 4.0-fold above baseline in animals administered 1, 10, 25 and 50 micrograms/kg/day, respectively. Maximum platelet counts were reached between 7 and 10 days after starting rHuMGDF and maintained for four days after the last dose. Thereafter, platelet counts decreased, reaching stable pretreatment values between 11 and 14 days after the last dose of rHuMGDF. No changes in red cell mass, peripheral blood white blood cell counts or differentials were observed during rHuMGDF treatment. For animals administered 10, 25 and 50 micrograms/kg/day of rHuMGDF, megakaryocytes increased more than threefold in marrow, were markedly enlarged, and had increased numbers of lobes. Overall marrow cellularity remained unchanged, as did red cell and white cell morphology. No marrow fibrosis was detected. Progenitor cells were not increased in marrow but did increase modestly in the peripheral blood, associated with increased numbers of CD34+ cells in the circulation. Following a single dose of 5-FU (120 mg/kg) animals were given either saline or pegylated (PEG) rHuMGDF (25 micrograms/kg/day) for 14 days. Platelet counts recovered to baseline by 13.8 +/- 1.8 days for PEG-rHuMGDF-treated baboons compared with 16.8 +/- 0.6 days for saline treated controls. Marrow biopsies revealed more rapid recovery of overall marrow cellularity and megakaryocytes in PEG-rHuMGDF-treated animals compared with controls. Thus, rHuMGDF specifically stimulates thrombopoiesis in normal and myelosuppressed baboons. rHuMGDF may be useful for stimulating thrombopoiesis in humans in clinical settings after myelosuppression.

Peptide helicity and membrane surface charge modulate the balance of electrostatic and hydrophobic interactions with lipid bilayers and biological membranes

An amphipathic model peptide, KLALKLALKALKAAKLA-NH2, and its complete double D-amino acid replacement set was used to analyze the process of peptide binding at lipid vesicles of different surface charge and to determine the structure of the lipid-bound peptides using CD spectroscopy. The relationship between peptide helicity, model membrane permeability, and biological activity has been studied by dye release from liposomes and investigation of antibacterial and hemolytic activity. The accumulation of cationic KLAL peptides at and the membrane-disturbing effect on bilayers of high negative surface charge were found to be dominated by charge interactions. Independent of any structural propensity, the cationic peptide side chains bind to the anionic phosphatidylglycerol moieties. The charge interactions hold the peptides at the bilayer surface, where they may disturb preferentially lipid headgroup organization by formation of peptide-lipid clusters. In contrast, KLAL peptide interaction with bilayers of low negative surface charge is highly dependent on peptide helicity. With decreasing amounts of anionic phosphatidylglycerol in the bilayer the membrane-disturbing effect of KLAL and other helical analogs substantially increases despite drastically reduced binding affinity. Less helical peptides exhibit reduced bilayer-disturbing activity, showing that the hydrophobic helix domain is decisive for binding at and inducing permeability in membranes of low negative surface charge. It is suggested that hydrophobic interactions drive the penetration of the amphipathic peptide structure into the inner membrane region, thus disturbing the arrangement of the lipid acyl chains and causing local disruption. On the basis of the proposed model for membrane disturbance, interactions modulating antibacterial and hemolytic activity are discussed.

Interaction of the receptor tyrosine kinase p145c-kit with the p210bcr/abl kinase in myeloid cells

The chimaeric bcr/abl oncogene is detected in virtually all cases of chronic myelogenous leukaemia (CML). It encodes a constitutively active tyrosine kinase of 210 kDalton, p210bcr/abl, which stimulates a variety of cytosolic signalling intermediates. The effects of bcr/abl on the activity of growth factor receptors are less well known. In order to investigate interaction of p210bcr/abl with the receptor tyrosine kinase p145c-kit, we used two myeloid, factor-dependent cell lines, MO7 and 32D, to generate bcr/abl positive sublines, MO7p210 and 32Dp210, by transfection with the bcr/abl gene. Since 32D and 32Dp210 cells did not express p145c-kit, a c-kit retrovirus was used to generate c-kit positive cell lines (32Dkit, 32Dp210kit). In contrast to MO7 and 32Dkit cells, MO7p210 and 32Dp210kit cells were factor independent and did not respond to the growth-promoting effects of recombinant human Steel factor (rhSF). Preincubation with a monoclonal antibody (MAb) neutralizing the binding of SF to p145c-kit did not affect the growth of MO7p210 cells, thus eliminating the possibility of an autocrine SF secretion. 32Dkit cells transfected with bcr/abl containing an inactivating point mutation (Lys-->Arg271) in the Abl kinase domain (32Dp210(Arg271)kit) retained their responsiveness to the effects of rhSF. Immune complex kinase assays showed that the kinase activity of p145c-kit was several-fold higher in MO7p210 and 32Dp210kit cells than in MO7, 32Dkit and 32Dp210(Arg271)kit cells, suggesting that Abl kinase activity was necessary to activate p145c-kit. Co-immunoprecipitation experiments with anti-Kit and anti-Abl MAbs demonstrated that p145c-kit and p210bcr/abl were associated in an intracellular complex in human bcr/abl positive, c-kit positive cell lines (MO7p210; GM/SO). Finally, colony assays with bone marrow from bcr/abl positive CML patients showed that the haemopoietic progenitors of three of four patients did not respond to rhSF. Taken together, the results suggest that p145c-kit can be activated by p210bcr/abl via an Abl-kinase dependent mechanism involving the complex formation of both proteins. These findings could explain some clinical features (basophilia, increase of immature myeloid cells) of chronic-phase CML.

p21ras supports the survival of chick embryonic motor neurones

Various trophic factors present in muscle extract can promote the survival of cultured motor neurones. However, little is known about the signal transduction pathways used in these cells. The proto-oncogene product p21ras has been shown to play an important role in proliferative and differentiative signalling pathways. We report here that cytoplasmic introduction of its oncogenic form, p21ras(G12V), fully supports the in vitro survival of chick embryonic motor neurones. The proto-oncogenic form of p21ras also showed a dose-dependent survival effect, while a C-terminally truncated counterpart of p21ras(G12V) was ineffective. These results suggest an involvement of p21ras in signal transduction pathways leading to motor neurone survival and may be of relevance for the development of therapeutic strategies for motor neurone disease.

Plasma and urine salsolinol in humans: effect of acute ethanol intake on the enantiomeric composition of salsolinol

The tetrahydroisoquinoline (TIQ) salsolinol (SAL), a condensation product of dopamine and pyruvate or acetaldehyde, is one of the neuropharmacologically active alkaloids in mammals. Previous HPLC studies have shown that the R-enantiomer of SAL is largely predominant, or is the only enantiomer in the urine of healthy subjects, whereas the S-enantiomer was found predominant in the urine of alcoholics. An enzymatic pathway for SAL formation that is influenced by chronic alcohol intake was proposed. However, our analyses showed that the SAL detectable in human urine and plasma is racemic, at least in healthy subjects. No change of the enantiomeric distribution was observed after an acute alcohol ingestion (1 g alcohol/kg body weight). Using a new method for the resolution of the SAL enantiomers and gas chromatography mass spectrometry analysis, the SAL enantiomers were quantified in the urine and plasma of 24 subjects before and after the intake of alcohol. Special dietary conditions were observed to avoid interferences by the SAL of the foodstuff. Although the distribution of SAL enantiomers was not changed after alcohol intake, the total urinary SAL output and the plasma concentration of SAL were significantly influenced in different ways. Only five subjects showed a significant increase both in plasma SAL concentration and in the total urinary SAL output, whereas 19 subjects showed decreased or unchanged SAL levels after alcohol administration. Data also show that only the subjects with low baseline levels (mean of 0.148 ng SAL/ml plasma) tend to increase SAL levels after ethanol ingestion, which may imply some genetic basis for the response.

Swelling, intracellular acidosis, and damage of glial cells

Cerebral ischemia and severe head injury among others are associated with a limited availability of oxygen, leading to cell catabolism as well as anaerobic glycolysis. Resulting metabolites, such as arachidonic- and lactic acid, can be expected to leak into perifocal brain areas, contributing there to cytotoxic swelling and damage of neurons and glia. Since elucidation of mechanisms underlying cell swelling and damage in the brain is difficult in vivo, respective investigations were carried out in vitro using suspended glial cells. Thereby, effects of arachidonic acid (AA) and of lactacidosis on glial cell volume, intracellular pH (pHi), and cell damage were analyzed utilizing flow cytometry. AA led to an immediate, dose dependent swelling and intracellular acidosis of glial cells. A concentration of 0.1 mM increased cell volume to 110% of control and decreased pHi to 7.05. Whereas glial swelling was permanent, pHi recovered to baseline after 90 min. Cell viability of 90% remained unchanged after addition of AA up to 0.1 mM, while at 0.5 mM it was significantly decreasing. Glial swelling from AA was nearly completely inhibited by the aminosteroid U-74389F or by using a Na(+)-free suspension medium for the experiment. Acidification of the medium to pH 6.8 or 6.2 led to a cell volume of 110% or 120% of control without affecting cell viability. The cells were not capable to defend their normal pHi during lactacidosis of the suspension medium but became acidotic as well. Addition of amiloride or utilization of Na(+)-free medium inhibited cell swelling from lactacidosis, while intracellular acidosis was even more pronounced. The results indicate that AA as well as acidosis are potent mediators of glial swelling and damage at levels found under pathophysiological conditions in the brain in vivo. Whereas intracellular acidification caused by AA was reversible, glial cells were unable to regulate their pHi during maintenance of extracellular acidosis. Concerning the mechanisms of glial swelling by AA, the production of oxygen- and lipid radicals might play a major role in the swelling process. The results indicate a role of the Na+/H(+)-antiporter in acidosis-induced glial swelling, whereas the exchanger has a limited significance for maintenance of pHi. As seen, the final pathway of glial swelling from both, AA and lactacidosis, requires a net influx of Na(+)-ions, probably together with Cl-ions, and osmotically obliged water.

Clearance and metabolism of arachidonic acid by C6 glioma cells and astrocytes

Effects of increased levels of arachidonic acid (AA) were analyzed in vitro by employment of C6 glioma cells and astrocytes from primary culture. The cells were suspended in a physiological medium added with arachidonic acid (AA) in a concentration range from 0.01 to 0.5 mM. The concentration profiles of the fatty acid and AA-metabolites were subsequently followed for 90 min. AA was measured by gas chromatography, whereas the AA-metabolites PGF2 alpha and LTB4 by radioimmunoassay (RIA). Following administration of AA at 0.05 or 0.1 mM the medium was completely cleared from the fatty acid within 10 to 15 min. However, when 0.5 mM were added, AA concentrations of 0.36 +/- 0.055 mM were found at 20 min, while 0.275 +/- 0.045 mM at 90 min. Addition of AA (0.1 mM) to cell-free medium was also associated with a steady decline of its concentration, although the decrease was markedly delayed as compared to the clearance in the presence of glial cells. AA was subjected to dose-dependent metabolisation in the cell suspension as demonstrated by the production of PGF2 alpha and LTB4. Following addition of 0.01 or 0.5 mM, concentrations of PGF2 alpha increased to a 1.9- or 4.9-fold level within 10 min, whereas those of LTB4 rose to a 1.3- or 33.7-fold level. This was attenuated or completely blocked, respectively, by the cyclo- and lipoxygenase inhibitor BW 755C. Formation of both metabolites from AA was also observed when studying astrocytes from primary culture. The current findings demonstrate an impressive efficacy of C6 glioma cells and astrocytes to clear arachidonic acid from the suspension medium and to convert the lipid compound into prostaglandins and leukotrienes. Uptake and metabolisation of AA by the glial elements may play an important role in vivo, for example in cerebral ischemia.

DNA polymerase delta of Physarum polycephalum

DNA polymerase delta from the phylogenetically ancient slime mold Physarum polycephalum has been 380-fold enriched from amoebae. It was found to have the properties typical for this type of DNA polymerase from higher eukaryotes with regard to effectors, template-primer acceptance, co-purification with 3'-5'-exonuclease activity, as well as the effect of endogenous proliferating cell nuclear antigen (PCNA) from amoebae on the stimulation and processivity of DNA synthesis. An identified cDNA fragment shows 65.5% identical amino acides with DNA polymerase delta from Saccharomyces pombe. The molecular mass of the polymerase is 125 kDa while that of PCNA is 35 kDa. During size-exclusion chromatography, the highly purified polymerase eluted in the position of 125 kDa, suggesting that no other proteins were tightly complexed with the enzyme. The DNA polymerases from the (mononucleate) amoebae and from the (multinucleate) plasmodia of P. polycephalum have very similar properties in contrast to their differences in phenotype and their mode of nuclear division. The polymerase shows a higher degree of similarity than DNA polymerase alpha, and especially the beta-like DNA polymerase, with the corresponding polymerases of higher eukaryotes. According to antibody staining, DNA polymerase delta is readily fragmented by proteases, even in the presence of inhibitor cocktails. Including freshly prepared cell lysates, proteolytic fragments are reproducible, the most abundant being 50 kDa in size. The DNA polymerase is recognized by the antisera against two peptides which have been derived by PCR-screening of plasmodial cDNA. One of the proteolytic splitting sites is located within an eight amino-acid stretch between the two antigenic sequences.

Habitat utilisation by Cape mountain zebras in the Mountain Zebra National Park, South Africa

This study investigated the seasonal patterns of vegetation community use by the Cape mountain zebra within the Mountain Zebra National Park over one seasonal cycle. Day-time censuses revealed that the zebras utilised all the different vegetation commu- nities that were defined in the park, with the exception of the riparian bush community. Year-round the zebras made greatest use of the grassland vegetation communities, together with those shrubland and dwarf shrubland communities that offered high grass biomasses. Selectivity for vegetation communities was greatest during the wet season, when the zebras favoured those grassland communities on the plateaus over other vegetation communities on the mountain slopes and in the ravines. During the dry season the zebras showed a greater diversity in their use of vegetation communities, and made greater use of those vegetation communities on the mountain slopes and in the ravines. The results suggest that the seasonal variations in vegetation community use by the zebras were in response to changes in the annual rainfall pattern.

Expression and characterization of the substance P (NK1) receptor in the rat pituitary and AtT20 mouse pituitary tumor cells

Although substance P is known to take part in the regulation of the anterior pituitary, no conclusive evidence for the expression of the tachykinin NK1 receptor has been found yet in the pituitary or pituitary derived cells. With the reverse transcription-polymerase chain reaction (RT-PCR) method we could detect the low abundant transcripts of the NK1 receptor in the rat pituitary and in the AtT20 cell line (clone D16v). Furthermore, the functional expression of the NK1 receptor in AtT20 cells was confirmed by activation of the phosphatidylinositol-calcium second messenger system when the cells were treated with substance P. In addition, binding studies also indicated the functional expression of this receptor in AtT20 cells. Thus we provide the first evidence that the NK1 receptor is expressed in AtT20 cells and the rat pituitary.

Effect of S(-)- and R(+)-salsolinol on the POMC gene expression and ACTH release of an anterior pituitary cell line

Tetrahydroisoquinolines (TIQs) are thought to play an important role in the process of development of alcohol dependence. Being a condensation product between the alcohol metabolite acetaldehyde and dopamine they might be involved in the balance of the opioid system as well as the reward system. Therefore, the influence of the TIQ salsolinol (SAL) on the pro-opiomelanocortin (POMC) gene expression was investigated using the ArT-20 mouse anterior pituitary tumor cell line. Our results show a significant decrease in the POMC gene expression by the S(-)-enantiomer of SAL. The basal secretion of adrenocorticotropin (ACTH) as well as the corticotropin-releasing factor (CRF)-stimulated ACTH released remained unchanged after R(+)- and S(-)-SAL treatment. Interestingly, it was clearly shown that a reduction of intracellular cAMP level occurred after the treatment of the cells with S(-)-SAL whereas R(+)-SAL did not affect the cAMP production. The obtained results suggest that S(-)-SAL is possibly involved in the establishment of the opioid deficiency in alcoholics.

Pulsed-laser excitation of acoustic modes in open high-Q photoacoustic resonators for trace gas monitoring: results for C(2)H(4)

The pulsed excitation of acoustic resonances was studied with a continuously monitoring photoacoustic detector system. Acoustic waves were generated in C(2)H(4)/N(2) gas mixtures by light absorption of the pulses from a transversely excited atmospheric CO(2) laser. The photoacoustic part consisted of high-Q cylindrical resonators (Q factor 820 for the first radial mode in N(2)) and two adjoining variable acoustic filter systems. The time-resolved signal was Fourier transformed to a frequency spectrum of high resolution. For the first radial mode a Lorentzian profile was fitted to the measured data. The outside noise suppression and the signal-to-noise ratio were investigated in a normal laboratory environment in the flow-through mode. The acoustic and electric filter system combined with the averaging of the photoacoustic signal in the time domain suppressed the outside noise by a factor of 4500 (73 dB). The detection limit for trace gas analysis of ethylene in pure N(2) was 2.0 parts in 10(9) by volume (ppbV) (minimal absorption coefficient α(min) = 6.1 × 10(-8) cm(-1), pulse energy 20 mJ, 1-bar N(2)), and in environmental air, in which the absorption of other gas components produces a high background signal, we can detect C(2)H(4) to ~180 ppbV. In addition, an alternative experimental technique, in which the maximum signal of the second azimuthal mode was monitored, was tested. To synchronize the sampling rate at the resonance frequency, a resonance tracking system was applied. The detection limit for ethylene measurements was α(min) = 9.1 × 10(-8) cm(-1) for this system.

Effects of voluntary ethanol ingestion on the POMC gene expression in the rat pituitary and on the plasma beta-endorphin content

Studies investigating the influence of chronic ethanol treatment on the beta-endorphin content and the proopiomelanocortin (POMC) gene expression in the rat pituitary revealed contradictory results. Because of this we decided to start a more complex study to investigate the effects of isolation stress, chronic ethanol treatment and voluntary ethanol consumption on the POMC mRNA level in the rat pituitary. The immediately prepared total RNA from rat pituitaries was used in hybridization experiments (Northern- and Dot-blots). The results suggest a correlation between the POMC gene expression and the different fashions of 'living conditions' tested. So the POMC gene expression in long-term alcohol-treated animals was decreased supporting the theory of beta-endorphin deficiency in alcoholism. More interestingly, data obtained from the group of voluntary ethanol consumption suggest an inverse correlation between total ethanol ingestion and POMC gene expression. This indicates the importance of the method of ethanol administration. Consistent with a decreased POMC gene expression in the pituitary during chronic ethanol treatment are previous studies showing a decrease in the plasma beta-endorphin content in such situations. Surprisingly, in the present study the plasma beta-endorphin levels measured by radioimmunoassay were only slightly decreased in chronically ethanol-treated rats. This may be due to dysregulatory effects of ethanol on post-translational processing, degradation and/or release of beta-endorphin.

Epiluminescence microscopy. A useful tool for the diagnosis of pigmented skin lesions for formally trained dermatologists

BACKGROUND AND DESIGN

Epiluminescence microscopy (ELM) is a noninvasive technique that, by employing the optical phenomenon of oil immersion, makes subsurface structures of the skin accessible for in vivo examination and thus provides additional criteria for the clinical diagnosis of pigmented skin lesions. At present, almost all studies about the value and clinical importance of ELM are based on data derived from ELM experts (ie, dermatologists specifically trained in this technique). In the present study, we attempt to determine whether the clinical diagnosis of pigmented skin lesions is significantly improved using ELM and whether ELM-trained individuals and dermatologists not trained in this technique profit equally from this technique. Randomly selected histologically proven pigmented skin lesion specimens, photographed with (ELM) and without oil immersion (surface microscopy) were presented by slide projection to six ELM experts and 13 ELM nonexperts (ie, dermatologists not formally trained in ELM) for diagnosis. To evaluate the diagnostic performance of ELM experts and nonexperts with and without the oil immersion technique (ie, ELM vs surface microscopy), the following parameters were obtained: intraobserver and interobserver agreement by kappa statistics and sensitivity and specificity of diagnostic performance.

RESULTS

Our results show that by using the ELM technique the ELM experts reach a substantially better intraobserver agreement than nonexperts (median kappa, 0.56 vs 0.36). The interobserver agreement was markedly increased in the ELM experts group (average gain, 7%) but decreased in the ELM nonexperts group (average loss, 6%). The sensitivity of diagnosis was significantly increased in the ELM experts group (average gain, 10%), but decreased in the nonexperts group (average loss, 10%). Finally, the specificity of diagnosis was excellent in the ELM experts group, both with and without oil immersion (0.91) and was somewhat improved by ELM in the nonexperts group (0.77 vs 0.85).

CONCLUSIONS

We conclude that the ELM technique increases sensitivity in formally trained dermatologists, but may decrease the diagnostic ability in dermatologists not formally trained in the ELM technique. Consequently, formal broad-based training in ELM should be offered to the dermatologic community.

Swelling, acidosis, and irreversible damage of glial cells from exposure to arachidonic acid in vitro

Swelling and damage of C6 glioma cells and of primary cultured astrocytes were analyzed in vitro during incubation with arachidonic acid (AA; 20:4). The cells were suspended in a physiological medium supplemented with AA at concentrations of 0.001-1.0 mM. Cell swelling was quantified by flow cytometry with hydrodynamic focusing. Flow cytometry was also utilized for assessment of cell viability by exclusion of the fluorescent dye propidium iodide and for measurement of the intracellular pH (pHi) by 2',7'-bis-(2-carboxyethyl)-5(and -6)carboxy-fluorescein. Administration of AA caused an immediate dose-dependent swelling of C6 glioma cells, even at a concentration of 0.01 mM. At this level cell volume increased within 20 min to 105.0% of control, at 0.1 mM to 111.0%, while at 1.0 mM to 123.7%. Following a phase of rapid cell volume increase, swelling leveled off during the subsequent observation period of 70 min. Viability of the C6 glioma cells was 90% under control conditions. It remained unchanged after raising AA concentrations to 0.1 mM. At 0.5 mM, however, cell viability fell to 72.8%, and at 1.0 mM to 32.7%. pHi of the glioma cells was 7.3 under control conditions. In parallel with the early swelling phase, AA led to a dose-dependent decrease of the intracellular pH and an elevated lactate production of the cells. During incubation with 0.1 mM AA, pHi decreased to 7.06 after 5 min, but recovered to normal subsequently. In addition, swelling-inducing properties of linoleic (18:2) or stearic (18:0) acid were analyzed for evaluation of the specificity of glial swelling induced by AA. Whereas stearic acid (0.1 mM) failed to induce a swelling response, linoleic acid (0.1 mM) was found to be effective. The volume increase of the glial cells, however, was only half of that found during exposure to AA at the same concentration. Further, glial swelling from AA or linoleic acid was completely inhibited by the aminosteroid U-74389F, an antagonist of lipid peroxidation. Finally, omission of Na+ ions in the suspension medium with replacement by choline led also to inhibition of the cell volume increase by AA. Experiments using astrocytes from primary culture confirmed the swelling-inducing properties of AA at a quantitative level, whereas vulnerability of the cells to AA was increased. The present results demonstrate an important role of AA in cytotoxic swelling and irreversible damage of glial cells at concentrations that occur in vivo in cerebral ischemia or trauma.(ABSTRACT TRUNCATED AT 250 WORDS)

Cloning, nucleotide sequence, and expression of the Bacillus subtilis lon gene

The lon gene of Escherichia coli encodes the ATP-dependent serine protease La and belongs to the family of sigma 32-dependent heat shock genes. In this paper, we report the cloning and characterization of the lon gene from the gram-positive bacterium Bacillus subtilis. The nucleotide sequence of the lon locus, which is localized upstream of the hemAXCDBL operon, was determined. The lon gene codes for an 87-kDa protein consisting of 774 amino acid residues. A comparison of the deduced amino acid sequence with previously described lon gene products from E. coli, Bacillus brevis, and Myxococcus xanthus revealed strong homologies among all known bacterial Lon proteins. Like the E. coli lon gene, the B. subtilis lon gene is induced by heat shock. Furthermore, the amount of lon-specific mRNA is increased after salt, ethanol, and oxidative stress as well as after treatment with puromycin. The potential promoter region does not show similarities to promoters recognized by sigma 32 of E. coli but contains sequences which resemble promoters recognized by the vegetative RNA polymerase E sigma A of B. subtilis. A second gene designated orfX is suggested to be transcribed together with lon and encodes a protein with 195 amino acid residues and a calculated molecular weight of 22,000.