A specific “at risk” profile related to recent stressful life events in euthymic major depressive disorder

Introduction

Stressful life events (SLE) may influence the illness course and outcome.

Objectives

The present study aimed to characterize socio-demographic and clinical characteristics of euthymic major depressive disorder (MDD) outpatients with SLE relative to those without.

Methods

This sample included 628 (mean age=55.1 ± 16.1) currently euthymic MDD outpatients, among them 250 (39.8%) reported SLE and 378 (60.2%) did not.

Results

After univariate analyses, outpatients with SLE were most frequently widowed and lived predominantly with friends/others. Furthermore, compared to outpatients without SLE, those with SLE were more likely to have a family history of suicidal behavior, manifested melancholic characteristics and higher Coping Orientation to the Problems Experienced (COPE) positive reinterpretation/growth and less likely to manifest a comorbid panic disorder, residual interepisodic symptoms, have used psychiatric medications, and use current antidepressant medications. After regression analyses, having a family history of suicide (OR=9.697; p=≤.05), history of psychotropic medications use (OR=2.888; p=≤.05), and reduced use of antidepressants (OR=.321; p=.001) were significantly associated with SLE. Mediation analyses demonstrated that the association between current use of antidepressants and SLE was mediated by previous psychiatric medications.

Conclusions

Having a family history of suicide, history of psychotropic medications use, and reduced use of antidepressants may confer a specific “at risk” profile related to the enhanced vulnerability to experience SLE.

Disclosure

No significant relationships.

Evidence for effective structure-based neuromodulatory effects of new analogues of neurosteroid allopregnanolone

The neurosteroid allopregnanolone (AP) modulates neuroendocrine/neurobiological processes, including hypothalamic-pituitary-adrenocortical activities, pain, anxiety, neurogenesis and neuroprotection. These observations raised the hope of developing AP-based therapies against neuroendocrine and/or neurodegenerative disorders. However, the pleiotropic actions of AP, particularly its cell-proliferation-promoting effects, hamper the development of selective/targeted therapies. For example, although AP-induced neurogenesis may serve to compensate neuronal loss in degenerative brains, AP-evoked cell-proliferation is contraindicated for steroid-sensitive cancer patients. To foster progress, we synthesised 4 novel AP analogues of neurosteroids (ANS) designated BR053 (12-oxo-epi-AP), BR297 (O-allyl-epi-AP), BR351 (O-allyl-AP) and BR338 (12-oxo-AP). First, because AP is well-known as allosteric modulator of GABAA receptors (GABAA-R), we used the electrophysiological patch-clamp technique to determine the structure-activity relationship of our ANS on GABAA-activated current in NCB20 cells expressing functional GABAA-R. We found that the addition of 12-oxo-group did not significantly change the respective positive or negative allosteric effects of 3α-AP or 3β-(epi)-AP analogues. Importantly, substitution of the 3α-hydroxyl-group by 3α-O-allyl highly modified the ANS activities. Unlike AP, BR351 induced a long-lasting desensitisation/inhibition of GABAA-R. Interestingly, replacement of the 3β-hydroxyl by 3β-O-allyl (BR297) completely reversed the activity from negative to positive allosteric action. In a second step, we compared the actions of AP and ANS on SH-SY5Y neuronal cell viability/proliferation using MTT-reduction assays. Different dose-response curves were demonstrated for AP and the ANS. By contrast to AP, BR297 was totally devoid of cell-proliferative effect. Finally, we compared AP and ANS abilities to protect against oxidative stress-induced neuronal death pivotally involved in neurodegenerative diseases. Both BR351 and BR297 had notable advantages over AP in protecting SH-SY5Y cells against oxidative stress-induced death. Thus, BR297 appears to be a potent neuroprotective compound devoid of cell-proliferative activity. Altogether, our results suggest promising perspectives for the development of neurosteroid-based selective and effective strategies against neuroendocrine and/or neurodegenerative disorders.

O-methyltransferase(s)-suppressed plants produce lower amounts of phenolic vir inducers and are less susceptible to Agrobacterium tumefaciens infection

The first step of Agrobacterium tumefaciens/plant interaction corresponds to the activation of a transduction pathway of the bacterium by plant exudate. Phenolic compounds rapidly secreted by wounded plant cells induce the expression of bacterial virulence (vir) genes; however, little is known about their biosynthesis in plant. Here we show that inoculation of an Agrobacterium tumefaciens virulent strain on orthodiphenol-O-methyltransferases-suppressed tobacco plants leads to significantly smaller tumors compared to control plants. These transgenic plants are inhibited for caffeic acid O-methyltransferase class I or II (OMT; EC 2.1.1.6) and/or caffeoyl-coenzyme A O-methyltransferase (CCoAOMT; EC 2.1.1.104) that are involved in monolignol biosynthesis. The significant decrease of tumor size could be suppressed by the pre-activation of bacterial virulence, before inoculation, using acetosyringone a known vir inducer. Total soluble phenolic amounts and cell wall composition analyzed by FT-IR analysis did not show significant differences between transgenic and control plants. The potential of phenolic extracts from control and OMT-suppressed plants to induce virulence was evaluated using an Agrobacterium tumefaciens reporter strain carrying a vir::LacZ gene fusion plasmid. Lower vir-inducing activities were recorded for plants that show inhibition to caffeic acid O-methyltransferase activity. HPLC analysis confirmed that the levels of several phenolic compounds were differently affected by wounding and/or by bacterial inoculation. Statistical correlations were established between tumor sizes, vir-inducing activities, O-methyltransferases proteins accumulations and the levels of various soluble phenolic compounds such as acetosyringone. These results demonstrate the role of the O-methyltransferases of the phenylpropanoid pathway in the early production of soluble Agrobacterium tumefaciens vir inducers.

Biological function of pathogenesis-related proteins: Four tobacco pathogenesis-related proteins are chitinases

Four endochitinases (poly[1,4-(N-acetyl-beta-D-glucosaminide)] glycanohydrolase, EC 3.2.1.14) have been purified from leaves of Nicotiana tabacum cv. Samsun NN reacting hypersensitively to tobacco mosaic virus. Two of them are acidic proteins of molecular weights 27,500 and 28,500 and have been identified as 2 of the 10 pathogenesis-related proteins that are known to accumulate in tobacco in response to stress or pathogen attack. These two pathogenesis-related proteins, named "P" and "Q" when their biological function was unknown, account for one-third of tobacco mosaic virus-induced chitinase activity of tobacco leaves. They are serologically closely related to the two other chitinases, which can be considered as new basic pathogenesis-related proteins. These two basic chitinases exhibit higher molecular weights (32,000 and 34,000) and higher specific enzyme activity than the two acidic isoforms.

Different apoptotic mechanisms are involved in the antiproliferative effects of 7beta-hydroxysitosterol and 7beta-hydroxycholesterol in human colon cancer cells

Plant sterols are found in fruits and vegetables. Their cholesterol-lowering effect is well documented. Our study aimed at comparing antiproliferative effects of 7beta-hydroxysitosterol (7beta-OHsito) versus 7beta-hydroxycholesterol (7beta-OHchol) on the human colon cancer cell line Caco-2. When cells were exposed for 32 h to 60 microM 7beta-OHsito or to 30 microM 7beta-OHchol, both compounds caused 50% growth inhibition. Cells treated with 7beta-OHsito showed enhanced caspase-9 and -3 activities followed by DNA fragmentation. In contrast, 7beta-OHchol did not activate caspase-3 and activation of caspase-9 and DNA fragmentation were delayed. The treatment of cells with the caspase inhibitor Z-VAD.fmk retarded the 7beta-OHsito-induced apoptotic process but not that triggered by 7beta-OHchol. Our data suggest that the two compounds in spite of their structural similarities target different cellular pathways, which lead to cell death.

Repression of O-methyltransferase genes in transgenic tobacco affects lignin synthesis and plant growth

Among the different enzymatic steps leading to lignin biosynthesis, two methylation reactions introduce the methyl groups borne by guaiacyl (G) and syringyl (S) units. Tobacco possesses a complex system of methylation comprising three classes of CCoAOMTs (caffeoyl-CoA-O-methyltransferases) and two classes of COMTs (caffeic acid OMTs). Antisense plants transformed with the CCoAOMT sequence alone or fused to COMT I sequence have been produced and compared to ASCOMT I plants in order to study the specific role of each OMT isoform in lignin biosynthesis, plant development and resistance to pathogens. Tobacco plants strongly inhibited in OMT activities have been selected and analyzed. Whereas antisense COMT I plants exhibited no visual phenotype, CCoAOMT repression was shown to strongly affect the development of both single and double transformants: a reduction of plant growth and the alteration of flower development were observed in the most inhibited plants. Lignin analysis performed by Klason and thioacidolysis methods, showed a decrease in the lignin quantity and changes in the lignin structure of ASCCoAOMT and ASCCoAOMT/ASCOMT I transgenics but not in ASCOMT I plants. Inhibition of COMT I in single as well as in double transformed tobacco was demonstrated to decrease S unit synthesis and to provoke the accumulation of 5-hydroxyguaiacyl lignin units. ASCCoAOMT/ASCOMT I tobacco was affected in lignin amount and composition, thus demonstrating additive effects of inhibition of both enzymes. The changes of lignin profiles and the phenotypical and molecular alterations observed in the different transgenic lines were particularly prominent at the later stages of plant development.

Effects of occlusion devices for minimally invasive coronary artery bypass surgery on coronary endothelial function of atherosclerotic arteries

BACKGROUND

During minimally invasive coronary artery bypass grafting surgery, technical devices are required to obtain an optimal operative field. However, these devices can cause lesions to the endothelium. Previous studies of the effect of devices on coronary endothelial function have been performed on normal coronary arteries. Balloon denudation is followed by regeneration of the endothelium, which is dysfunctional and by intimal hyperplasia resembling atherosclerosis. The Anastaflo (Baxter, Mississauga, Ontario, Canada) shunt is a surgical device used during the performance of coronary anastomoses that allows a continuous flow inside the artery during the surgery.

METHODS

We compared the effects of three commonly used techniques on endothelial function: 1) using the Anastaflo shunt, 2) using Retract-o-tape (Genzyme, Cambridge, MA) silicone air cushion snaring, and 3) using a bulldog clamp on arteries submitted to balloon denudation 30 days prior to the surgical experiment on an in vivo model of beating heart off-pump coronary artery bypass (OPCAB). Balloon denudation was performed on the left anterior descending artery and on the right coronary artery. The devices were applied for 15 minutes on porcine epicardial coronary arteries, on the beating heart, after median sternotomy. Denuded control rings were taken at the site of denudation on which no devices were applied while non-denuded control rings were taken from the left circumflex artery. The endothelial function of control and instrumented arterial rings was studied in organ chambers filled with a modified Krebs-Ringer bicarbonate solution. After contraction to prostaglandin F(2)alpha, endothelium-dependent relaxation to serotonin (an agonist coupled to Gi-proteins) and bradykinin (a non-Gi-protein coupled agonist) were compared in the shunting group, the snaring group, the clamping group, and in controls.

RESULTS

There was a significant decrease in the relaxations to serotonin and bradykinin in the denuded control group compared with the non-denuded control group, confirming that balloon denudation caused an endothelial dysfunction. However, there was no significant difference between the denuded control group and the hemostatic device groups (shunting, snaring and clamping) in the relaxation to serotonin.

CONCLUSION

These results suggest that hemostatic devices used for OPCAB do not cause any greater injury in atherosclerotic coronary arteries already harbouring an endothelial dysfunction. The effects on platelet aggregation, intimal dissection, and plaque rupture remain to be determined.

[Protective effect of appendectomy on the development of ulcerative colitis. A case-control study]

AIMS

To examine by a case-control study the relationship between appendectomy and subsequent ulcerative colitis development in a French population.

METHODS

A total of 150 patients with ulcerative colitis were matched for age (+/- 5 years) and sex, with 150 controls recruited in a preventive medicine center. The following data were collected from medical records and by standardised questionnaire in consultation or by phone: appendectomy and tonsillectomy before the onset of ulcerative colitis, smoking habits and area of residence.

RESULTS

The rate of previous appendectomy in patients with ulcerative colitis was 8% (12/150) compared with 30.6% (46/150) in the control group (P=0.001). There was no significant association between ulcerative colitis and tonsillectomy (25.3 and 27.3% in the control and the ulcerative colitis groups, respectively). Smoking was more frequent in the control group (36%) than in the ulcerative colitis group (25.3%) but the difference was not significant (P=0.07). In multivariate analysis, the risk of developing ulcerative colitis was significantly lower after previous appendectomy (odds ratio=0.26; 95% confidence interval: 0.13-0.55; P=7 x 10(-4)).

CONCLUSION

Our study confirms the inverse association between appendectomy and subsequent ulcerative colitis, in a French population, after adjusting on smoking.

Soluble phospholipase A2 activity is induced before oxylipin accumulation in tobacco mosaic virus-infected tobacco leaves and is contributed by patatin-like enzymes

Recent evidence suggests that oxidized lipid-derived molecules play significant roles in inducible plant defence responses against microbial pathogens, either by directly deterring parasite multiplication, or as signals involved in the induction of sets of defence genes. The synthesis of these oxylipins was hypothesized to be initiated by the phospholipase A2-mediated release of unsaturated fatty acids from membrane lipids. Here, we demonstrate that, in tobacco leaves reacting hypersensitively to tobacco mosaic virus, a strong increase in soluble phospholipase A2 (PLA2) activity occurs at the onset of necrotic lesion appearance. This rapid PLA2 activation occurred before the accumulation of 12-oxophytodienoic and jasmonic acids, two fatty acid-derived defence signals. Three PLA2 isoforms were separated and the most active enzyme was partially purified, its N-terminal sequence displaying similarity with patatin, the major storage protein in potato tubers. Three related tobacco patatin-like cDNAs, called NtPat1, NtPat2 and NtPat3, were cloned, with NtPat2 encoding the PLA2 isolated from infected leaves. RT-PCR experiments showed a rapid transcriptional activation of the three NtPat genes in virus-infected leaves, preceding the increase in PLA2 activity. Recombinant NtPat1 and NtPat3 enzymes were active in an assay using labelled bacterial membranes, and also displayed high bona fide PLA2 activity on phosphatidylcholine substrate. These results point to a possible new role of patatin-like phospholipases in inducible plant defence responses. The induction kinetics together with the enzymatic activity data indicate that the NtPat proteins may provide precursors for oxylipin synthesis during the hypersensitive response to pathogens.

The pharmacokinetics of ziprasidone in healthy volunteers treated with cimetidine or antacid

AIMS

To evaluate the effects of cimetidine and Maalox(R) (aluminium hydroxide 1.35 g and magnesium hydroxide 1.2 g) on the pharmacokinetics of ziprasidone.

METHODS

Eleven healthy young subjects aged 18-45 years were given single oral doses of ziprasidone 40 mg on three occasions at least 7 days apart. On one occasion ziprasidone was administered alone, on another occasion ziprasidone was co-administered with oral cimetidine 800 mg and on a third occasion ziprasidone was co-administered with oral Maalox(R).

RESULTS

The administration of cimetidine increased the ziprasidone AUC(0,infinity) by 6% but there were no statistically significant differences in Cmax, tmax or lambda(z) between the ziprasidone+cimetidine group and the ziprasidone group. The administration of Maalox did not produce any statistically significant differences in AUC(0,infinity), Cmax, tmax or lambda(z) between the ziprasidone+Maalox group and the ziprasidone group.

CONCLUSIONS

The pharmacokinetics of ziprasidone are not affected by concurrent administration of cimetidine or Maalox. This suggests that other nonspecific inhibitors of cytochrome P450 and antacids are unlikely to alter the pharmacokinetics of ziprasidone.

Hydrogen peroxide from the oxidative burst is neither necessary nor sufficient for hypersensitive cell death induction, phenylalanine ammonia lyase stimulation, salicylic acid accumulation, or scopoletin consumption in cultured tobacco cells treated with elicitin

H(2)O(2) from the oxidative burst, cell death, and defense responses such as the production of phenylalanine ammonia lyase (PAL), salicylic acid (SA), and scopoletin were analyzed in cultured tobacco (Nicotiana tabacum) cells treated with three proteinaceous elicitors: two elicitins (alpha-megaspermin and beta-megaspermin) and one glycoprotein. These three proteins have been isolated from Phytophthora megasperma H20 and have been previously shown to be equally efficient in inducing a hypersensitive response (HR) upon infiltration into tobacco leaves. However, in cultured tobacco cells these elicitors exhibited strikingly different biological activities. beta-Megaspermin was the only elicitor that caused cell death and induced a strong, biphasic H(2)O(2) burst. Both elicitins stimulated PAL activity similarly and strongly, while the glycoprotein caused only a slight increase. Only elicitins induced SA accumulation and scopoletin consumption, and beta-megaspermin was more efficient. To assess the role of H(2)O(2) in HR cell death and defense response expression in elicitin-treated cells, a gain and loss of function strategy was used. Our results indicated that H(2)O(2) was neither necessary nor sufficient for HR cell death, PAL activation, or SA accumulation, and that extracellular H(2)O(2) was not a direct cause of intracellular scopoletin consumption.

Tobacco O-methyltransferases involved in phenylpropanoid metabolism. The different caffeoyl-coenzyme A/5-hydroxyferuloyl-coenzyme A 3/5-O-methyltransferase and caffeic acid/5-hydroxyferulic acid 3/5-O-methyltransferase classes have distinct substrate specificities and expression patterns

The biosynthesis of lignin monomers involves two methylation steps catalyzed by orthodiphenol-O-methyltransferases: caffeic acid/5-hydroxyferulic acid 3/5-O-methyltransferases (COMTs) and caffeoyl-coenzyme A (CoA)/5-hydroxyferuloyl-CoA 3/5-O-methyltransferases (CCoAOMTs). Two COMT classes (I and II) were already known to occur in tobacco (Nicotiana tabacum) and three distinct CCoAOMT classes have now been characterized. These three CCoAOMT classes displayed a maximum level of expression at different stages of stem development, in accordance with their involvement in the synthesis of lignin guaiacyl units. Expression profiles upon tobacco mosaic virus infection of tobacco leaves revealed a biphasic pattern of induction for COMT I, COMT II, and CCoAOMTs. The different isoforms were expressed in Escherichia coli and our results showed that CCoAOMTs and, more surprisingly, COMTs efficiently methylated hydroxycinnamoyl-CoA esters. COMT I was also active toward 5-hydroxyconiferyl alcohol, indicating that COMT I that catalyzes syringyl unit synthesis in planta may operate at the free acid, CoA ester, or alcohol levels. COMT II that is highly inducible by infection also accepted caffeoyl-CoA as a substrate, thus suggesting a role in ferulate derivative deposition in the walls of infected cells. Tobacco appears to possess an array of O-methyltransferase isoforms with variable efficiency toward the diverse plant o-diphenolic substrates.

Clinical comparability of albuterol delivered by the breath-actuated inhaler (Spiros) and albuterol by MDI in patients with asthma

STUDY OBJECTIVE

This study compares the efficacy and safety of one and two actuations of albuterol sulfate powder delivered via a breath-actuated, effort-assisted, investigational inhaler (Spiros, Dura Pharmaceuticals, Inc) and albuterol delivered via a conventional propellant-driven metered dose inhaler (Ventolin, Glaxo, Inc).

DESIGN

Randomized, double-blind, placebo-controlled, 5-way crossover study.

PARTICIPANTS

Sixty patients with mild-to-moderate asthma (FEV1 59% predicted) were enrolled and 44 completed the study.

MEASUREMENTS AND RESULTS

FEV1 values over 6 hours were analyzed by ANCOVA and the Finney relative potency model. The relative potency of the inhalers (albuterol MDI: albuterol DPI) was 1.132 (90% CI, 0.680 to 2.252) indicating 1.132 actuations of albuterol MDI provided the same bronchodilation as one actuation of albuterol DPI. ANCOVA analyses further indicated that there were no significant differences between the two delivery systems with respect to FEV1, FVC, FEF25-75%, or PEF. Both inhalers had similar effects on serum potassium levels, QTc interval, blood pressure, and heart rate.

CONCLUSIONS

In patients with mild-to-moderate asthma in this study, the albuterol DPI was determined to be therapeutically comparable to albuterol MDI in the delivery of one and two actuations of albuterol.

Isoniazid poisonings in New York City

We identified 41 New York City residents who had been hospitalized at least overnight between January 1992 and September 1993 because of a toxic isoniazid (INH) exposure. Review of the available medical charts of 33 patients revealed that median age was 19 years, 27 (82%) were females, and 24 (83%) were taking INH chemoprophylaxis for tuberculosis infection. Twenty-two patients had seizures. Twenty-seven (82%) patients had attempted suicide using INH, and another three patients had intentionally misused INH by making up missed doses at one time. All patients survived. Physicians should be aware of the potential for INH toxicity and should assess their patients' current mental and psychosocial status when prescribing it. INH toxicity should be considered when young patients, particularly females, present with unexplained intractable seizures, and treatment with pyridoxine should be given.

Expression of G proteins in human placentas from pregnancies complicated by gestational hypertension

Preeclampsia (gestational hypertension) is accompanied by decreased hPL and increased hCG levels in maternal serum. The expression of these peptides as well as the endocrine mechanisms responsible for their regulation in preeclampsia are unknown. We have demonstrated that regulatory GTP-binding proteins (G proteins) are implicated in the modulation of hPL production by placentas from normal pregnancies. In order to extend our knowledge on placental endocrinology, we analyzed in this study the expression of hPL and beta-hCG mRNAs as well as placental G protein alpha-subunits in pregnancies complicated by gestational hypertension. Western and Northern blot analyses were respectively performed on membrane protein and total mRNA preparations from human placentas of preeclamptic (n = 7) and normal pregnancies (n = 4). The levels of hPL and beta-hCG mRNAs were respectively 108% and 105% of those from normal placentas, suggesting that the altered circulating levels of hPL and beta-hCG are not related to dysfunctional mRNA expression of these peptides. The autoradiographs for G proteins and their mRNAs showed no difference in G protein expression between preeclamptic and normal tissues. Specifically, G alpha i2, G alpha i3, G alpha o, G alpha s, and G alpha q/11 levels reached 87%, 81%, 91%, 99%, and 103% respectively of those from normal placentas. In parallel with the protein levels, their mRNAs expression were respectively 93%, 89%, 113%, 104%, and 94% of normal values for G alpha i2, G alpha i3, G alpha o, G alpha s, and G alpha q/11. These results suggest that neither a change in hPL and beta-hCG expression nor a change in signal transduction machinery is implicated in the altered circulating levels of hPL and beta-hCG in preeclampsia.

Expression of angiotensin II type-I receptor and phospholipase C-linked G alpha q/11 protein in the human placenta

OBJECTIVE

A recent study on the distribution of angiotensin II (ANG II), ANG II (AT) receptors, and human placental lactogen in human placental tissues from term pregnancies showed positive correlations among these indices, suggesting an important role for ANG II in placental endocrinology. However, nothing is known about the ontogenesis of this functional role for ANG II during pregnancy. Therefore, the aim of this study was to investigate the placental AT receptor expression at various trimesters of pregnancy. We also studied the ontogenesis of phospholipase C-linked G alpha q/11 protein, which is known to transduce ANG II type-1 (AT1) receptor signal.

METHODS

Western blot analysis of placental membrane proteins was performed using a chemiluminescence kit and specific antibodies against AT1 receptor and G alpha q/11 protein. Northern blot analyses of AT1 receptor and G alpha q/11 mRNA expression were accomplished using random primed [32P]dCTP-labeled specific probes.

RESULTS

The autoradiographs of AT1 receptor mRNAs (2.4 kb) and proteins (83 kDa) showed a progressive 4.8-fold and 2.6-fold increase, respectively, during pregnancy, with maximal levels at term. We also observed progressive 1.8-fold and 4.5-fold increases of G alpha q/11 protein (43 kDa) and mRNAs (4.5, 6.0, and 7.1 kb), respectively, during pregnancy, with maximal levels observed at term.

CONCLUSION

Our results demonstrate that both the human placental AT1 receptor content and the G alpha q/11 protein level increase during pregnancy, and suggest that the AT1 receptor pathway may play a role in human placental physiology.

Expression of G proteins in human placentae from molar pregnancies

Hydatidiform mole is a conceptus, usually devoid of an intact fetus, with variable proliferation of trophoblast and altered placental protein synthesis, including high human chorionic gonadotropin (hCG) and low human placental lactogen (hPL) production. Little is known about the control of the production of these two placental proteins in molar pregnancies. Regulatory guanine 5'triphosphate (GTP)-binding proteins (G proteins) play key roles in the endocrine control of peptide production by the placenta. The present authors recently demonstrated that Gi2, Gi3 Go, and Gs alpha-subunits were expressed in normal human placenta throughout pregnancy. This study analysed the expression of placental G protein alpha-subunits in molar pregnancies. Western and Northern blot analyses were performed on membrane protein and total mRNA preparations of human placentae, respectively, from hydatidiform mole (n = 5) and normal pregnancies (n = 4). The levels of hPL and beta-hCG mRNAs were 60 and 237 per cent respectively, of those from normal placentae. The autoradiographs for G proteins and their mRNAs showed decreased expression in molar placentae in comparison with normal tissues. Specifically, G alpha i2, G alpha i3, G alpha o, and G alpha s levels reached 39, 4, 42, and 89 per cent, respectively, of those from normal placentae. In parallel with the protein levels, their mRNAs expression were 8, 3, 54 and 65 per cent of normal values for G alpha i2, G alpha i3, G alpha o, and G alpha s, respectively. The results demonstrate important changes in placental G protein expression in hydatidiform moles suggesting alterations in the signal transduction machinery within the molar trophoblast.

Expression of human placental G proteins during pregnancy

OBJECTIVE

Regulatory guanine nucleotide-binding proteins (G proteins) play key roles in the stimulus-response coupling of many important biological systems. Recent studies from our laboratory suggest a functional role for many G proteins in the human placenta. However, the expression of these proteins has not yet been reported. Therefore, the aims of this investigation were to identify the expression of placental G protein alpha subunits in human placenta, and to study their level of variation during pregnancy.

METHODS

Western and Northern blot analyses were performed on membrane protein and mRNA preparations, respectively, of human placentas from the first (7-11 weeks), second (16-19 weeks), and third (term) trimesters.

RESULTS

The autoradiographs of both proteins and mRNA showed differential expression of placental G proteins during pregnancy. Thus, the relative levels of G alpha i2 and G alpha i3 subunits were highest during the first trimester, whereas no differences were observed between second-trimester and term placentas for both subunits. The levels of placental G alpha o and G alpha s subunits stayed relatively stable during pregnancy.

CONCLUSION

The demonstration of human placental G alpha protein expression during pregnancy provides new insight into the components of the signal transduction machinery within trophoblast. However, the physiologic significance of the variations of placental G alpha i protein expression during pregnancy remains to be investigated.

Molecular characterization of a novel tobacco pathogenesis-related (PR) protein: a new plant chitinase/lysozyme

A new PR (pathogenesis-related) protein was isolated from tobacco leaves (Nicotiana tabacum cv. Samsun NN), reacting hypersensitively to tobacco mosaic virus (TMV), by zinc chelate chromatography and was therefore named Pz. Its reactivity toward several lectins indicated the presence of bound sugar residues. From the amino acid sequence of tryptic peptides, Oligonucleotide primers were derived which allowed the synthesis of Pz cDNA by PCR. Using this cDNA as probe, near full-length clones were isolated from a library made from poly(A)+ RNA purified from TMV-infected leaves. Sequence analysis revealed similarities with chitinases/lysozymes of various origins and the purified protein was, indeed, shown to hydrolyse different N-acetylglucosamine-containing substrates. Comparison of peptide and cDNA sequences indicated that Pz protein is synthesized as a pre-pro-protein, a seven-amino acid C-terminal peptide probably being involved in the vacuolar targeting of the protein. Pz mRNA and protein were demonstrated to accumulate strongly in TMV-infected tobacco leaves. Pz transcripts were also found in various tissues of healthy plants, indicating that Pz gene expression is developmentally regulated.

Diagnosing and treating lateral epicondylitis

Lateral epicondylitis is often encountered in primary care. Although its diagnosis can be fairly straightforward, its treatment is often difficult. This review examines the epidemiology, pathophysiology, and clinical presentation of tennis elbow. Management options are discussed.

Molecular cloning and expression of a new class of ortho-diphenol-O-methyltransferases induced in tobacco (Nicotiana tabacum L.) leaves by infection or elicitor treatment

In tobacco (Nicotiana tabacum L. cv Samsun NN), three distinct enzymes account for ortho-diphenol-O-methyltransferase (OMT) activity. OMT I is the major enzyme of healthy leaves, whereas enzymes OMT II and III are preferentially induced during the hypersensitive reaction to tobacco mosaic virus (TMV). Using an anti-OMT III antiserum, we isolated a partial OMT III cDNA clone by immunoscreening an expression library made from mRNA of TMV-infected tobacco leaves. Using this OMT III clone as a probe, we isolated a full-length clone with a deduced amino acid sequence encompassing all of the sequences obtained by Edman degradation of both purified proteins II and III. Thus, OMT II and III of tobacco are likely to be encoded by the same genes and to arise from different posttranslational modifications. Sequence analysis showed that this OMT clone represents a new class of OMT enzymes (class II) with a low level of similarity (53-58%) to OMTs cloned previously from other dicotyledonous plants. Southern analysis indicated that a small family of class II OMT genes inherited from ancestors related to Nicotiana sylvestris and Nicotiana tomentosiformis occurs in the tobacco genome. RNA blot analysis demonstrated that class II OMT genes, unlike class I OMT genes, are not expressed at a high constitutive level in lignified tissues of tobacco. Class II OMT transcripts were found to accumulate in tobacco leaves infected with TMV or treated with megaspermin, a proteinaceous elicitor from Phytophthora megasperma, but not in leaves treated with salicylic acid, a molecule known to trigger many defense genes. In TMV-infected or elicitor-treated tissues, a marked increase in catechol-methylating activity accompanied the accumulation of class II OMT gene products.

cDNA cloning and gene expression analysis of the microbial proteinase inhibitor of tobacco

Tobacco mosaic virus-infected tobacco (Nicotiana tabacum var. Samsun NN) leaves produce a serine proteinase inhibitor that has evolved a specificity for microbial proteinases. We have isolated two closely related cDNAs that were shown to encode two active inhibitors. Southern analysis of genomic DNA, comparison of deduced amino acid sequences, and characterization of the two separated proteins suggest that the two genes of tobacco are homologous originating from each parent. Amino acid sequences deduced from the cDNAs exhibit a glutamic residue at the P1 position of the active site, known to determine the specificity of this type of inhibitors. Nevertheless, the V8 proteinase from Staphylococcus aureus, an enzyme that cleaves polypeptides after glutamic acid residues, was found to be unaffected by the tobacco inhibitor. We demonstrate strong accumulation of the two mRNAs and proteins during the hypersensitive reaction of tobacco to tobacco mosaic virus. Messengers and products of the two genes are present in a 3:2 ratio, in infected leaves as well as in upper uninfected leaves, the induction being markedly lower at distance from the infection site. The transcripts were also found in sepals and petals of healthy plants, indicating that these genes are also developmentally regulated. Unlike the tomato and potato I inhibitors, the tobacco inhibitor was only weakly induced by wounding, but was expressed upon salicylic acid or ethephon treatment, as many pathogenesis-related proteins.

Plant 'pathogenesis-related' proteins and their role in defense against pathogens

The hypersensitive reaction to a pathogen is one of the most efficient defense mechanisms in nature and leads to the induction of numerous plant genes encoding defense proteins. These proteins include: 1) structural proteins that are incorporated into the extracellular matrix and participate in the confinement of the pathogen; 2) enzymes of secondary metabolism, for instance those of the biosynthesis of plant antibiotics; 3) pathogenesis-related (PR) proteins which represent major quantitative changes in soluble protein during the defense response. The PRs have typical physicochemical properties that enable them to resist to acidic pH and proteolytic cleavage and thus survive in the harsh environments where they occur: vacuolar compartment or cell wall or intercellular spaces. Since the discovery of the first PRs in tobacco many other similar proteins have been isolated from tobacco but also from other plant species, including dicots and monocots, the widest range being characterized from hypersensitively reacting tobacco. Based first on serological properties and later on sequence data, the tobacco PRs have been classified in five major groups. Group PR-1 contains the first discovered PRs of 15-17 kDa molecular mass, whose biological activity is still unknown, but some members have been shown recently to have antifungal activity. Group PR-2 contains three structurally distinct classes of 1,3-beta-glucanases, with acidic and basic counterparts, with dramatically different specific activity towards linear 1,3-beta-glucans and with different substrate specificity. Group PR-3 consists of various chitinases-lysozymes that belong to three distinct classes, are vacuolar or extracellular, and exhibit differential chitinase and lysozyme activities. Some of them, either alone or in combination with 1,3-beta-glucanases, have been shown to be antifungal in vitro and in vivo (transgenic plants), probably by hydrolysing their substrates as structural components in the fungal cell wall. Group PR-4 is the less studied, and in tobacco contains four members of 13-14.5 kDa of unknown activity and function. Group PR-5 contains acidic-neutral and very basic members with extracellular and vacuolar localization, respectively, and all members show sequence similarity to the sweet-tasting protein thaumatin. Several members of the PR-5 group from tobacco and other plant species were shown to display significant in vitro activity of inhibiting hyphal growth or spore germination of various fungi probably by a membrane permeabilizing mechanism.(ABSTRACT TRUNCATED AT 400 WORDS)

Regulation of enzymes involved in lignin biosynthesis: induction of O-methyltransferase mRNAs during the hypersensitive reaction of tobacco to tobacco mosaic virus

The mRNAs encoding orthodiphenol-O-methyltransferases (OMTs; EC 2.1.1.6), which are involved in the biosynthesis of lignin precursors, are highly induced in tobacco leaves during the hypersensitive reaction to tobacco mosaic virus (TMV). OMT messengers were fractionated on a sucrose gradient and translated in vitro. Protein A-Sepharose columns adsorbed with specific antisera raised against purified OMTs were used to select translation products, and the translatable activity of OMT mRNA was measured at different stages of infection. Oligonucleotides derived from peptide sequences of purified OMT I were used to prime polymerase chain reactions; total RNA was used as template to allow the isolation of an OMT I clone. RNA blots, hybridized with the OMT I probe, revealed a unique messenger of 1.7 kb. The kinetics of accumulation of OMT I mRNAs during the hypersensitive reaction to TMV parallels the kinetics of translation and suggests that an increase in mRNA controls the increase in the rate of enzyme synthesis. In healthy plants, RNA blot hybridization showed that the steady-state level of OMT I mRNA is very high in vascular tissue compared to the level measured in leaves.

Two Apoplastic alpha-Amylases Are Induced in Tobacco by Virus Infection

alpha-Amylase activity (EC 3.2. 1.1) is greatly increased in leaves of tobacco (Nicotiana tabacum L. cv Samsun NN) infected with tobacco mosaic virus (TMV). The kinetics of enzyme induction during the hypersensitive reaction resemble those of other hydrolases known to be pathogenesis-related proteins of tobacco. Two alpha-amylases were purified from TMV-infected leaves and shown to have features in common with well-characterized pathogenesis-related proteins: they are acidic monomers that can be separated upon electrophoresis on basic native gels, and they are found in the apoplastic compartment of the cell. This extra-cellular localization was demonstrated by comparing the alpha-amylase partition between the intercellular wash fluid and the cell extract with that of proteins of known cellular compartmentalization. These data indicate an active secretion of both alpha-amylases produced in tobacco upon TMV infection.

Isolation and characterization of a proteinaceous inhibitor of microbial proteinases induced during the hypersensitive reaction of tobacco to tobacco mosaic virus

A proteinase inhibitor is strongly induced in tobacco leaves reacting hypersensitively to tobacco mosaic virus. The tobacco inhibitor is highly active against four different serine endoproteinases of fungal and bacterial origin (EC 3.4.21.14) but inhibits poorly two serine endoproteinases of animal origin, trypsin (EC 3.4.21.4) and chymotrypsin (EC 3.4.21.1). The inhibitor has been purified to homogeneity by successive steps of conventional and high-performance liquid chromatography. When electrophoresed under denaturing conditions, it behaves as a small polypeptide with a molecular weight of about 6,000. From its amino acid composition and NH2-terminal amino acid sequence analysis, it appears that the inhibitor belongs to the potato inhibitor I family. A polyclonal antiserum was raised against the purified tobacco inhibitor and was used in immunoblotting experiments to follow inhibitor accumulation during the hypersensitive reaction of tobacco to tobacco mosaic virus. The inhibitor is highly efficient and might represent a potent fungicide and/or bactericide to be used in plant biotechnology.

Route of delivery of phenylalanine influences its effect on short-term food intake in adult male rats

The effect of phenylalanine (Phe) on plasma and brain Phe and tyrosine (Tyr) levels and on short-term food intake in male rats was measured after intragastric (i.g.), subcutaneous (s.c.) and intraperitoneal (i.p.) administration. Compared to equimolar alanine (Ala), which served as the control, Phe significantly suppressed feeding at a dose of 90 mg/kg body wt when given i.p., but doses up to 720 mg/kg body wt had no effect when given i.g. or s.c. The high doses of Phe given by the i.g. or s.c. route resulted in higher levels of Phe in both plasma and brain than those following i.p. injection (90 mg/kg body wt). Furthermore, brain Tyr levels after i.g. Phe (720 mg/kg body wt) were equal to or higher than after i.p. Phe (90 mg/kg body wt). We conclude that the route of administration is an important variable influencing the effects of Phe on feeding behavior, and that these effects are not readily explained by plasma or brain Phe and Tyr concentrations.

Purification of tobacco O-methyltransferases by affinity chromatography and estimation of the rate of synthesis of the enzymes during hypersensitive reaction to virus infection

The three tobacco (Nicotiana tabacum L.) S-adenosyl-L-methionine: o-diphenol-O-methyltransferases (OMTs; EC 2.1.1.6) were purified to homogeneity by affinity chromatography on adenosine-agarose. Amounts and catalytic actities of the enzymes were measured in tobacco leaves during the hypersensitive reaction to tobacco mosaic virus. The drastic increase in activity of each enzyme upon infection was shown to arise from the accumulation of enzymatic protein with constant specific enzymatic activity. Rates of OMT synthesis were determined from pulse-labeling experiments with L-[(14)C]leucine injected into the leaves. The specific radioactivities of the homogenous enzymes were compared in healthy and tobacco mosaic virus-infected tobacco. The results demonstrated that increase in OMT amounts is a consequence of de novo synthesis of the enzymes.

Nadolol for prophylaxis of gastrointestinal bleeding in patients with cirrhosis. A randomized trial

This controlled trial was designed to evaluate the prophylactic effect of nadolol on gastrointestinal bleeding in cirrhotic patients with large oesophageal varices who had never bled. Nadolol or placebo was given randomly to two groups of 53 patients. The percentage of patients free of gastrointestinal bleeding 1 year after inclusion in the study was 83 +/- 6% (mean +/- S.D.) in the nadolol group and 80 +/- 6% in the placebo group. In the nadolol and placebo groups, 40 and 47 patients, respectively, were compliant, i.e., took nadolol or placebo continuously. The percentage of patients who were free of bleeding 1 year after inclusion was 97 +/- 3% in the subgroup of compliant nadolol patients. This percentage was significantly higher than that of patients who were free of bleeding in the placebo group (P less than 0.03) as well as in the subgroup of compliant placebo patients (77 +/- 6%; P less than 0.02). We concluded that, although there was no overall significant effect of nadolol on the risk of bleeding in cirrhotic patients in good condition with large oesophageal varices, this study suggests that nadolol reduced the risk of bleeding in compliant patients.

Comparative haemodynamic effects of betaxolol and propranolol in patients with cirrhosis

The acute effects of betaxolol (10 mg, intravenously), a new cardioselective beta-blocker, and propranolol (15 mg, intravenously) on splanchnic and systemic circulations were studied in two matched groups of six patients with portal hypertension due to cirrhosis. Similar decreases in hepatic venous pressure gradient and azygous blood flow--an estimation of superior portosystemic shunts--were observed after both drugs, whereas hepatic blood flow was not modified. The decreases in heart rate and cardiac index were also similar after betaxolol and propranolol. Both drugs induced a significant decrease in the fraction of cardiac output flowing through superior portosystemic shunts. These findings confirm that the marked effect of beta-adrenoceptor blocking agents on splanchnic circulation results both from the reduction in cardiac output and from a vasoconstriction of the portal vein territory, and demonstrate that this vasoconstriction of the portal vein area does not necessitate a beta 2-blocking activity of the drug. The similar efficiency of the two agents in decreasing the hyperkinetic circulation suggests that betaxolol merits further long-term study in the pharmacologic treatment of portal hypertension.

Biological function of ‘pathogenesis-related’ proteins: four PR proteins of tobacco have 1,3-β-glucanase activity

Three of the ten acidic ;pathogenesis-related' (PR) proteins known to accumulate in Nicotiana tabacum cv Samsun NN reacting hypersensitively to tobacco mosaic virus, namely -O, -N and -2, have been shown to have 1,3-beta-glucanase (EC 3.2.1.39) activity. By using sera raised against each protein purified to homogeneity close serological relationships have been demonstrated between the three proteins. The same specific sera cross-reacted with a basic protein which is also a 1,3-beta-glucanase induced by virus infection and which can be considered as a new basic pathogenesis-related protein of tobacco. Protein PR-O and the basic 1,3-beta-glucanase display about the same specific enzymatic activity, i.e. 50-fold and 250-fold higher than specific activities of proteins PR-N and -2 respectively.