Subcellular localization and endocytosis of homomeric gamma2 subunit splice variants of gamma-aminobutyric acid type A receptors

The expression of alpha and beta gamma-aminobutyric acid type A receptor subunits produces GABA-gated channels which require the incorporation of either the gamma2 or gamma3 subunit for benzodiazepine modulation. Here we examine the role of the gamma2 subunit splice variants, gamma2S and gamma2L which differ by eight amino acids in the major intracellular domain, in mediating cell surface expression. Using immunocytochemistry we have demonstrated that when expressed alone, the gamma2S subunit can access the cell surface and internalize constitutively. In contrast, alpha1, beta2 and gamma2L are retained predominantly in the endoplasmic reticulum (ER) when expressed alone. Replacing the insert which differentiates gamma2L from gamma2S (LLRMFSFK) with eight alanines produces a phenotype identical to gamma2S. Both gamma2 subunits fail to produce high molecular weight oligomers observed for alpha1beta2 and alpha1beta2gamma2 heterooligomers and do not form functional ion channels. Surface expression of gamma2S is repressed upon the coexpression of alpha1 or beta2 subunits, resulting in ER-retained heterooligomers, suggesting that homomeric gamma2S is unlikely to occur in vivo. However, its independent maturation to surface competence and preferential assembly with alpha and beta subunits may ensure the production of functional benzodiazepine-sensitive receptors. Furthermore, the presence of the gamma2 subunit appears to confer an endocytotic capacity to these heterooligomeric receptors.

Excision repair defect in Rothmund Thomson syndrome

Rothmund Thomson syndrome is a rare autosomal recessive skin disorder. The main clinical feature is poikiloderma appearing in early childhood associated with skeletal abnormalities. Early occurrence of malignancies is another relevant feature. Here we describe the clinical features of 2 patients with Rothmund Thomson syndrome who were investigated for the in vitro DNA repair capacities of blood cells following UVC radiation exposure. DNA excision repair, assessed with unscheduled DNA synthesis following UVC exposure, was decreased in both patients. Such a defect might explain the patients' sensitivity to sunlight and the relatively high risk of cancer associated with this syndrome.

Effects of joint lavage and steroid injection in patients with osteoarthritis of the knee: results of a multicenter, randomized, controlled trial

OBJECTIVE

To evaluate the efficacy of joint lavage and intraarticular steroid injection, alone and in combination, in the treatment of patients with symptomatic knee osteoarthritis (OA).

METHODS

Ninety-eight patients with painful tibiofemoral OA were enrolled in a prospective, randomized, controlled, 2 x 2 factorial-design trial of 6 months' duration. The 4 treatment groups consisted of 1) intraarticular placebo (1.5 ml of 0.9% normal saline), 2) intraarticular corticosteroids (3.75 mg of cortivazol in 1.5 ml), 3) joint lavage and intraarticular placebo, and 4) joint lavage and intraarticular corticosteroid. Outcome measures evaluated at baseline, week 1, week 4, week 12, and week 24 included severity of pain (100-mm visual analog scale [VAS]), global status (100-mm VAS), and Lequesne's functional index.

RESULTS

No interaction between steroid injection and joint lavage was demonstrated. Patients who had undergone joint lavage had significantly improved pain VAS scores at week 24 (P = 0.020). In contrast, corticosteroid injection had no long-term effect (P = 0.313); corticosteroid injection was associated with a decrease in pain only at week 1 (P = 0.003) and week 4 (P = 0.020). After week 4, Lequesne's functional index was not significantly improved regardless of the assigned treatment.

CONCLUSION

Compared with placebo, both treatments significantly relieved pain but did not improve functional impairment. The effects of the 2 treatments were additive. Cortivazol provided short-term relief of pain (up to week 4). The effects of joint lavage persisted up to week 24.

Haemoptysis after breath-hold diving

Pulmonary oedema has been described in swimmers and self-contained underwater breathing apparatus (Scuba) divers. This study reports three cases of haemoptysis secondary to alveolar haemorrhage in breath-hold divers. Contributory factors, such as haemodynamic modifications secondary to immersion, cold exposure, exercise and exposure to an increase in ambient pressure, could explain this type of accident. Furthermore, these divers had taken aspirin, which may have aggravated the bleeding.

Cloning and phylogenetic relationship of red drum somatolactin cDNA and effects of light on pituitary somatolactin mRNA expression

The nucleotide sequence for red drum somatolactin (SL) cDNA was determined and the expression of pituitary SL mRNA was examined in red drum kept under various light conditions. A full length of SL cDNA (1629 bp) was isolated and characterized from a red drum pituitary cDNA library. The SL cDNA has an open reading frame of 696 nucleotides which encodes a 24-amino-acid signal peptide and a 207-amino-acid mature peptide. Red drum SL shares 58-87% amino acid sequence identity and 56-85% nucleotide sequence identity with other teleost SLs. The characteristic seven cysteine residues and one N-glycosylation site of SL are well conserved in the red drum SL mature peptide. Phylogenetic analysis shows that red drum SL is closely related to seabream SL and is also closely related to lumpfish, flounder, halibut, and sole SLs, whereas SLs of Atlantic cod, chum salmon, rainbow trout, and eel are more distantly related to those of the more advanced teleosts. Two SL transcripts, designated as SL I at 1.8 kb and SL II at 1.3 kb, are expressed in red drum pituitaries and correspond to two polyadenylation signal sites in red drum SL cDNA at nucleotide positions 1554 and 1270. Levels of the SL I mRNA were 2- to 4-fold higher in pituitaries of blind red drum and intact fish kept under constant darkness for 1 week than those in control fish sampled during the light phase of the light-dark cycle. Similarly, pituitary levels of SL II mRNA were 9-fold higher in blind fish and 1.6- to 4-fold higher in intact fish kept under constant darkness than in the control fish. Furthermore, these changes in mRNA levels in pituitaries were accompanied by more than 10-fold increases in SL protein concentrations in plasma. The finding that the absence of light perception for extended periods leads to dramatic increases in SL mRNA expression as well as SL secretion in red drum provides further evidence that illumination levels and SL physiology are intimately related in this species.

Lack of association between juvenile myoclonic epilepsy and HLA-DR13

PURPOSE

We sought to replicate and extend a previously reported positive association between juvenile myoclonic epilepsy and HLA-DR13.

METHODS

Ninety-three subjects with juvenile myoclonic epilepsy and 93 normal blood donors, entirely of white origin with their families mostly of French extraction, underwent DNA-based HLA-DR13 and DQB6 typing.

RESULTS

None of the investigated alleles or combination of alleles (DRB1*1301-DQB1*0603 or DRB1*1302-DQB1*0604) showed a significant difference between patients and controls.

CONCLUSIONS

Unlike previously reported positive association, in this population, there is no evidence that susceptibility to juvenile myoclonic epilepsy is associated with HLA-DR13.

Keratinocyte growth factor induced epithelial proliferation facilitates retroviral-mediated gene transfer to distal lung epithelia in vivo

BACKGROUND

Cell proliferation, vector titer and accessibility of target cells represent hurdles for efficient gene transfer to lung epithelia in vivo using recombinant murine leukemia (MuLV)-based retroviruses. We tested the hypothesis that the pulmonary epithelium is susceptible to retroviral-mediated gene transfer when stimulated to proliferate by a mitogen, keratinocyte growth factor (KGF).

METHODS

Rats received keratinocyte growth factor (KGF, 2.5 micrograms/g x 4 doses, two consecutive days) intratracheally followed by high titer amphotropic retrovirus expressing beta-galactosidase. Gene transfer was assessed five days later.

RESULTS

KGF stimulated transient proliferation in the bronchiolar and alveolar epithelia (30-40% PCNA positive cells at peak) which decreased to background levels seven days after administration. Gene transfer to epithelia (X-Gal positive cells) occurred more frequently in KGF treated rats, but proliferation exceeded the level of gene transfer. X-gal positive cells were noted in the alveolar epithelium and occasionally in the bronchiolar epithelium. In order to understand the discrepancy between the number of proliferating and transduced cells, primary rat tracheal epithelium cultured at the air-liquid interface was infected from either the apical or basolateral side. Gene transfer was achieved only through basolateral application of vector, suggesting that epithelial polarity represents a barrier to MuLV-based lung gene transfer in vivo.

CONCLUSIONS

KGF transiently stimulates epithelial proliferation in vivo, facilitating MuLV-based gene transfer. Retroviral vectors may encounter multiple barriers which have evolved to defend the lung from infections.

A case of agitated catatonia

Agitation is one of the diagnostic features of catatonia in the DSM IV classification, but permanent forms of agitated catatonia have occasionally been described. We report the case of a 43-year-old man who had already suffered from undifferentiated schizophrenia for 7 years, and in whom we diagnosed agitated catatonia. While our patient was being treated with a neuroleptic during a second episode of paranoia, a state of agitation was observed which persisted for a further 8 months. During this period, he was treated with several different neuroleptics and benzodiazepines, either alone or in association, without any improvement. No organic cause was found. He was then transferred to our electroconvulsive therapy (ECT) unit, with a diagnosis of schizophrenic agitation resistant to drug therapy. ECT was begun, and he was only given droperidol in case of agitation and alimemazine for insomnia, neither of which had any effect. In view of his persistent agitation without any purpose, echolalia and echopraxia, stereotyped movements with mannerisms and marked mimicking and grimacing, we diagnosed him as having agitated catatonia. After the fourth session of ECT, we decided to stop all treatment and gave him lorazepam at a dose of 12.5 mg daily. Twenty-four hours later, all symptoms of agitation had disappeared. In our opinion, permanent catatonic agitation is not rare. In our case, the neuroleptic treatment maintained and may even have worsened the symptomatology. Lorazepam can be used as a therapeutic test for this type of agitation, especially if it does not respond to neuroleptics. This also allows the patient to be sedated rapidly and effectively, thus preventing him from injuring himself further.

Acetaldehyde inhibits NF-kappaB activation through IkappaBalpha preservation in rat Kupffer cells

BACKGROUND AND AIMS

Treatment with acetaldehyde dehydrogenase inhibitors leads to increased liver acetaldehyde levels and prevents hepatic inflammation and necrosis in ethanol-fed rats. This is accompanied by IkappaBa preservation and decreased activation of nuclear factor (NF)-kappaB. The present in vitro study was aimed to clarify whether acetaldehyde has an effect on degradation of IkappaBalpha and activation of NF-kappaB in LPS-stimulated rat Kupffer cells.

METHODS

Kupffer cells were isolated from male Sprague-Dawley rats and preincubated with various concentrations of acetaldehyde (25-100 microM). Thereafter the cells were stimulated with LPS, and cytosolic and nuclear fractions were prepared. IkappaBalpha and p65 proteins and activation of NF-kappaB were evaluated.

RESULTS

In LPS-stimulated rat Kupffer cells, acetaldehyde diminished proteolytic degradation of IkappaBalpha, inhibited nuclear translocation of cytosolic p65 protein, and, accordingly, markedly decreased NF-kappaB activation.

CONCLUSIONS

Acetaldehyde is clearly involved in the stabilization of IkappaBalpha protein and suppression of NF-kappaB activation in rat Kupffer cells. Acetaldehyde may form an adduct with IkappaBalpha, thus making the protein less susceptible to degradation.

Divided attention in major depression

Depressive illness has been reported to interfere with effortful processing, which requires conscious attention. The aim of this study was to evaluate divided attention in depressed patients, as a function of the degree of difficulty of the task performed. Tasks designed to measure unimodal and bimodal reaction times were presented to 10 patients with major depression and 10 normal control subjects. Performance was evaluated both before treatment when the patients were depressed and after treatment when they had recovered. Unlike the unimodal trials, the bimodal reaction time tasks were designed to evaluate decision-making under conditions in which attention was divided between two perceptual channels. Reaction times were measured under two different conditions in order to assess the extent of the response delay induced by divided attention, modality shifting, and decision processing. During simple response tasks, the depressed patients displayed significantly greater lengthening of reaction times when their attention was divided between two perceptual channels. This cross-modal delay effect occurred both for stimuli of the same modality and when shifting between modalities. The cross-modal delay effect was evident only for the choice tests in both the depressed and the recovered patients, but only the recovered patients were as accurate as the control subjects. These results suggest that the need for decision processing in depressed patients results in a failure to allocate the mental resources required to complete interchannel shifting, when attention is divided between two perceptual channels. These data are consistent with the hypothesis that attentional regulation is impaired in major depression.

Eubacterium aggreganssp. nov., a New Homoacetogenic Bacterium from Olive Mill Wastewater Treatment Digestor

A strictly anaerobic, homoacetogenic, gram-positive, non spore-forming bacterium, designated strain SR12(T) (T = type strain), was isolated from an anaerobic methanogenic digestor fed with olive mill wastewater. Yeast extract was required for growth but could also be used as sole carbon and energy source. Strain SR12(T) utilized a few carbohydrates (glucose, fructose and sucrose), organic compounds (lactate, crotonate, formate and betaine), alcohols (methanol), the methoxyl group of some methoxylated aromatic compounds, and H2 + CO2. The end-products of carbohydrate fermentation were acetate, formate, butyrate, H2 and CO2. End-products from lactate and methoxylated aromatic compounds were acetate and butyrate. Strain SR12(T) was non-motile, formed aggregates, had a G+C content of 55 mol % and grew optimally at 35 degrees C and pH 7.2 on a medium containing glucose. Phylogenetically, strain SR12(T) was related to Eubacterium barkeri, E. callanderi, and E. limosum with E. barkeri as the closest relative (similarity of 98%) with which it bears little phenotypic similarity or DNA homology (60%). On the basis of its phenotypic, genotypic, and phylogenetic characteristics, we propose to designate strain SR12(T) as Eubacterium aggregans sp. nov. The type strain is SR12(T) (= DSM 12183).

Adhesion of colorectal carcinoma cells to the endothelium is mediated by cytokines from CEA stimulated Kupffer cells

We hypothesize that a major factor regulating hepatic metastasis is the ability of CEA (carcinoembryonic antigen) producing colorectal carcinomas to activate Kupffer cells. CEA and NCA (nonspecific cross-reacting antigen) bind to an 80 kDa Kupffer cell receptor by the peptide sequence PELPK and stimulate cytokine production. Cytokines induce sinusoidal endothelial cells to express intercellular adhesion molecules and increase adhesion of the tumor cells and retention in the liver. In this study human Kupffer cells were activated in vitro with CEA, NCA, and the peptide PELPK. This resulted in release of IL-1beta, TNF-alpha and IL-6. CEA non-producing MIP-101 colon carcinoma cells labeled with 51Cr were incubated on monolayers of ECV-304 human umbilical vein endothelial cells treated with these Kupffer cell derived cytokines or with comparable recombinant human (rH) cytokines. Specific antibodies to the adhesion molecules ICAM-1, VCAM-1, E-selectin and beta2integrin were used to block their functions. A significant enhancement in the adhesion of colorectal carcinoma cells occurred when endothelial cells were stimulated with a very low concentration of Kupffer-cell derived cytokines. Activated endothelium demonstrated significant up-regulation primarily of ICAM-1. The adhesion was blocked by an antibody to ICAM-1. A combination of Kupffer-cell derived cytokines was more effective than IL-1beta or TNF-alpha alone. IL-6 alone did not influence adhesion under our conditions. Our results suggest a mechanism for CEA in the modulation of colorectal carcinoma adhesion to the hepatic endothelium and its enhancement of metastatic potential.

A single-chain immunotoxin against carcinoembryonic antigen that suppresses growth of colorectal carcinoma cells

We have engineered an anti-carcinoembryonic antigen (CEA) single-chain immunotoxin derived from humanized anti-CEA antibody (hMN14) and a truncated Pseudomonas exotoxin (PE), PE40. The purified anti-CEA immunotoxin (hMN14(Fv)-PE40) was first measured for binding affinity against a CEA-positive colorectal carcinoma cell line and compared with its parental IgG and the monovalent Fab fragment. The Ka of sFv-PE40, Fab, and IgG were 5 x 10(7), 6 x 10(7), and 3 x 10(8) M(-1), respectively. There was no significant affinity loss by conversion of Fab to the single-chain Fv, but these monovalent forms were 5-6-fold reduced in affinity compared with the parental IgG. In cytotoxicity assays, the hMN14(Fv)-PE40 showed specific growth suppression of CEA-expressing colon cancer cell lines MIP-CEA (high CEA) and LS174T (moderate CEA) with IC50s of 12 ng/ml (0.2 nM) and 69 ng/ml (1.1 nM). These IC50s correlated inversely with the surface expression of CEA, such that 50% killing was equivalent for each cell type when expressed in toxin molecules bound/cell (3000-5000). The presence of soluble CEA up to 1000 ng/ml did not affect the cytotoxicity against CEA-expressing cells, with 50% suppression only at 4000 ng/ml that correlated with the binding Kd of the single-chain Fv. The stability of the hMN14(Fv)-PE40 molecule at 37 degrees C was confirmed by bioassay and by lack of aggregation. Our hMN14(Fv)-PE40 may be clinically useful for tumors with high CEA expression without affecting normal tissues with low or absent CEA, even in patients with high soluble antigen levels.

Effect of pindolol on onset of action of paroxetine in the treatment of major depression: intermediate analysis of a double-blind, placebo-controlled trial. Réseau de Recherche et d'Expérimentation Psychopharmacologique

OBJECTIVE

The purpose of this study was to investigate the effect of pindolol to accelerate the onset of action of paroxetine in patients suffering from major depression.

METHOD

Patients who met DSM-IV criteria for a nonpsychotic disorder, who had no previously treated episode of major depression episode, and who had a score of at least 18 on the 17-item Hamilton Depression Rating Scale were randomly assigned, for the first 21 days, to treatment with paroxetine (20 mg/day) and either pindolol (5 mg t.i.d.) or placebo. Patients were evaluated with the Hamilton depression scale, the Montgomery-Asberg Depression Rating Scale, and Global Clinical Impression (CGI) on days 0 (baseline), 5, 10, 15, 21, 25, 31, 60, 120, and 180.

RESULTS

Intermediate analysis of the first month's results for the first 100 patients (pindolol, N=50; placebo, N=50) was performed. At day 10 there were more improved patients (defined as patients with a maximum score of 10 on the Hamilton depression scale) in the pindolol plus paroxetine group (N=24; 48%) than in the placebo plus paroxetine group (N=13; 26%). At day 5 there was no statistically significant difference, and at day 15 and thereafter, the differences between the two groups disappeared. Hamilton depression scale scores were significantly lower on days 5 and 10 for the pindolol plus paroxetine group (mean=15.7, SD=5.3, and mean=11.7, SD=6.4, respectively) than for the placebo plus paroxetine group (mean=19, SD=5.9, and mean=14.7, SD=6.8); this was also true for Montgomery-Asberg depression scale and CGI scores.

CONCLUSIONS

The addition of pindolol to paroxetine treatment significantly accelerates the onset of therapeutic response in patients suffering from major depression. Nevertheless, the mechanism (pharmacodynamic or pharmacokinetic) of this beneficial effect remains unclear.

Isolation of developmentally regulated genes by differential display screening of cDNA libraries

mRNA differential display RT-PCR has been extensively used for the isolation of genes differentially expressed between RNA populations. We have assessed its utility for the identification of developmentally regulated genes in plasmid cDNA libraries derived from individual tissues dissected from early mouse embryos. Using plasmid Southern blot hybridisation as a secondary screen, we are able to identify such genes and show by whole-mount in situ hybridisation that their expression pattern is that expected from the differential display profile.

Aminobacterium colombiensegen. nov. sp. nov., an Amino Acid-degrading Anaerobe Isolated from Anaerobic Sludge

A new gram-negative, non-sporulating, mesophilic, amino acid fermenting bacterium, designated strain ALA-1(T) (T = type strain), was isolated from an anaerobic lagoon of a dairy wastewater treatment plant. The strain is curved (3-4 microm x 0.2-0.3 microm) and occurs singly or in pairs. Optimum growth occurs at 37 degrees C and pH 7.3. The G+C content of the DNA is 46 mol %. The strain requires yeast extract for growth, grows poorly on casamino acids, peptones, cysteine, and alpha-ketoglutarate, but readily grows on serine, threonine, glycine and pyruvate. When cocultured with the hydrogenotrophic methanogen Methanobacterium formicicum, strain ALA-1(T) oxidized alanine, glutamate, leucine, isoleucine, valine, aspartate, and methionine. Phylogenetic analysis revealed that it forms a distinct and independent line of descent in the vicinity of Dethiosulfovibrio peptidovorans, Dictyoglomus thermophilum, and Anaerobaculum thermoterrenum which are members of the low G+C containing gram-positive bacteria. The phylogenetic results concur with the phenotypic and genomic data which reveal that it is a novel strain. Based on these findings, we designate strain ALA-1(T) as Aminobacterium colombiense (DSM 12261) gen. nov., sp. nov.