bluuebunny/crossref_metadata_2025 huggingface dataset:
Bantu and European Y‐lineages in Sub‐Saharan Africa
Authors: PEREIRA L. , GUSMÃO L. , ALVES C. , AMORIM A. , PRATA M. J.
Published: March 2003

Ancient diversity in Sub‐Saharan Africa is known to have been re‐modulated to a large extent by Bantu migrations in the sub‐Sahel region, in two southwards waves of advance through both the west and east coasts. Haplotype matching performed for Y‐STR haplotypes in several sub‐Saharan populations, both inside and outside the migration path, allowed the confirmation of a putative founder haplotype, and its one‐step neighbours, of Bantu origin, and detected an increasing drift towards the south, with a stronger reduction of diversity along the western coast. A mixed frequency distribution for the Bantu haplotype core in South Africa, relative to the western and eastern pools, seems to provide evidence for the intermingling between both Bantu waves in that region. The proportion of male lineages considered as predating the Bantu expansion reached 8.8% in Mozambique. Further influence on sub‐Saharan diversity may have occurred during the colonial period; in Mozambique, the European genetic impact in the male component was estimated to be around 5.9%, in significant contrast with the female counterpart where no European lineages were detected.
Genetic relationships among some tribal groups inhabiting the north‐eastern, eastern and sub‐Himalayan regions of India
Authors: CHAKRABARTI C. S. , ROY M. , SENGUPTA N. K. , LALTHANTLUANGA R. , MAJUMDER P. P.
Published: March 2003

The origins and genomic affinities of various tribal populations of India are of considerable contemporary interest. In this study, we have investigated relationships among five tribal groups inhabiting the north‐eastern, eastern and sub‐Himalayan regions of India. DNA samples have been analysed in respect of 25 polymorphic loci, based on which genetic affinities have been estimated. The interesting findings of this study are (i) the Tibeto‐Burman speaking, morphologically Mongoloid, tribal groups of India are not genetically very homogeneous, and (ii) the Tharu, a group inhabiting the sub‐Himalayan region, may indeed have undergone considerable admixture as has been postulated by some anthropologists.
Autosomal Microsatellite and mtDNA Genetic Analysis in Sicily (Italy)
Authors: Romano V. , Calì F. , Ragalmuto A. , D'Anna R. P. , Flugy A. , De Leo G. , Giambalvo O. , Lisa A. , Fiorani O. , Di Gaetano C. , Salerno A. , Tamouza R. , Charron D. , Zei G. , Matullo G. , Piazza A.
Published: March 2003

DNA samples from 465 blood donors living in 7 towns of Sicily, the largest island of Italy, have been collected according to well defined criteria, and their genetic heterogeneity tested on the basis of 9 autosomal microsatellite and mitochondrial DNA polymorphisms for a total of 85 microsatellite allele and 10 mtDNA haplogroup frequencies. A preliminary account of the results shows that: a) the samples are genetically heterogeneous; b) the first principal coordinates of the samples are correlated more with their longitude than with their latitude, and this result is even more remarkable when one outlier sample (Butera) is not considered; c) distances among samples calculated from allele and haplogroup frequencies and from the isonymy matrix are weakly correlated (r = 0.43, P = 0.06) but such correlation disappears (r = 0.16) if the mtDNA haplogroups alone are taken into account; d) mtDNA haplogroups and microsatellite distances suggest settlements of people occurred at different times: divergence times inferred from microsatellite data seem to describe a genetic composition of the town of Sciacca mainly derived from settlements after the Roman conquest of Sicily (First Punic war, 246 BC), while all other divergence times take root from the second to the first millennium BC, and therefore seem to backdate to the pre‐Hellenistic period.

A more reliable association of these diachronic genetic strata to different historical populations (e.g. Sicani, Elymi, Siculi), if possible, must be postponed to the analysis of more samples and hopefully more informative uniparental DNA markers such as the recently available DHPLC‐SNP polymorphisms of the Y chromosome.
Simultaneous Detection of ACP1 and GC Genotypes Using PCR/SSCP
Authors: Dissing J. , Thymann M. , Hopkinson D.
Published: March 2003

The classical enzyme and protein markers ACP1 and GC have gained new importance because of the biological functions of their gene products. ACP1 encodes a low molecular weight enzyme which is now recognized as a phosphotyrosine phosphatase with a role in the regulation of signal transduction pathways, and GC‐globulin acts both as a transporter of vitamin D and as a plasma actin scavenger and plays a role in macrophage activation. These two polymorphisms were phenotyped for decades on the basis of electrophoretic isozyme or protein patterns; the gene structures are now known. Nucleotide substitutions determining the common alleles are close enough at each locus to be contained in one short PCR product. We have developed a simple, rapid and reliable multiplex method based on PCR and SSCP which allows the simultaneous determination of the common ACP1 and GC genotypes.
Tuberous Sclerosis: from Tubers to mTOR
Authors: Kwiatkowski D. J.
Published: March 2003

Tuberous sclerosis (TSC) is an autosomal dominant hamartoma syndrome whose causative genes (TSC1andTSC2) were identified 5 and 9 years ago respectively. Their encoded proteins are large, and apart from a strong binding interaction with each other, relatively little was known about their biochemical function. Recent studies inDrosophilahave pinpointed a critical function for theDrosophilaTSC1/TSC2homologues in the regulation of cell size. Epistasis experiments and a variety of biochemical studies that followed have indicated a critical function for these proteins in the highly conserved PI‐3‐kinase‐Akt‐mTOR signalling pathway.
Populations of aphids, whiteflies and associated predators and parasites on different vegetables cultivated in plastic greenhouses
Authors: Zaki F. N. , El‐Shaaraway M. F. , Farag N. A.
Published: March 2003

During 1996 and 1997, populations of aphids and whiteflies and their parasites were studied in plastic greenhouses under a chemical control program and in those free of pesticides. In the greenhouses free of pesticides, the parasite A. colemani destroyed 14.7 % of the aphids. B. tabaci had no effect on the cucumbers during the spring cultivation. However, it attacked the autumn cultivation. The parasite E. mundus killed 30 % of these nymphs.

 The parasite A. colemani parasitized up to 10 % of aphids on tomato plants in greenhouses free of chemical pesticides. The parasite E. mundus killed 15.7 % of whitefly nymphs.

 In greenhouses under a chemical pesticides program, aphids and whiteflies were found on the plants at the end of the plantation season, after the pesticide spraying had stopped. Although the pest population was low, the parasite A. colemani parasitized 8 % of the aphid population. Whiteflies were not found on tomato plants in greenhouses under extensive pesticides use.
Side effects of some fungicides on phytoseiid mites (Acari, Phytoseiidae) in north‐Italian vineyards
Authors: Pozzebon A. , Duso C. , Pavanetto E.
Published: March 2003

The effects of fungicides containing mancozeb or copper oxychloride, as principal active ingredients, on phytoseiid mites were investigated in a vineyard comprising four varieties (Prosecco, Cabernet Franc, Pinot gris and Merlot) and located in north‐eastern Italy. Phytoseiid colonisation was different among the four varieties: Amblyseius andersoni and Kampimodromus aberrans were dominant on Pinot gris and Merlot, respectively, while Typhlodromus pyri was more common than the above species on Prosecco and Cabernet Franc. Applications of mancozeb fungicides significantly affected K. aberrans populations. Concerning T. pyri, a significant effect was observed on Cabernet but not on Prosecco. The effects of mancozeb fungicides on A. andersoni were less clear. The response of phytoseiids to fungicides containing mancozeb appeared to be mediated by the variety. Therefore, the choice of one or two varieties as a standard reference for field tests is recommended. These results also suggest that the side effects of fungicides on predatory mites should be studied on different phytoseiid species and, possibly, on susceptible and resistant strains in order to gain useful insights.
Development of the red palm weevil, Rhynchophorus ferrugineus (Olivier), (Coleoptera, Curculionidae) on natural and synthetic diets
Authors: Salama H. S. , Abdel‐Razek A. S.
Published: March 2003

The development of the red palm weevil, Rhynchophorus ferrugineus (Olivier) was investigated on a newly developed semiartificial diet as compared with two natural diets namely sugarcane stem and banana fruit. The weevil was successfully maintained on these diets and duration of the life cycle for males and females, respectively were 164.97 and 194.61 days on the semiartificial diet, 192.5 and 186.5 days on banana, and 172.00 and 170.00 days on sugarcane. The average egg production per female was shown to be significantly higher on the semiartificial diet, being 184.00 ± 18.68 eggs compared with an average of 125.00 ± 11.97 and 133.00 ± 15.21 eggs on banana and sugarcane, respectively. The fertility ranged between 94 – 100 % in those eggs deposited by females previously reared on the tested diets. The developed semiartificial diet was shown to be suitable for maintaining laboratory colonies of the red palm weevil, and it can substitute natural diets.
Russian wheat aphid, Diuraphis noxia (Kurdj.) under adverse weather conditions (2001) (Hom., Aphididae)
Authors: Starý P. , Lukášová H.
Published: March 2003

Cool and wet weather in some periods of the season generally supressed the RWA (Diuraphis noxia Kurdj.) populations in the Czech republic in 2001. However, some sites manifested population levels ranging out of the population mean stated per area, and these sites were also apparently responsible for respective peaks of alate aphids sampled by suction traps. An analysis of these sites determined them to be attributed to some poor quality barley fields in a warmer area of the state. RWA is known to vary in all‐over populations in different years, and the year 2001 illustrated its capability of its surviving even unfavourable periods and seasons, remaining well‐established in the area.
Sucking rates of the white‐backed planthopper Sogatella furcifera (Horv.) (Homoptera, Delphacidae) and yield loss of rice
Authors: Zhu Z.‐R. , Cheng J.
Published: March 2003

The sap‐sucking rates of the white‐backed planthopper (WBPH) Sogatella furcifera (Horv.) (Homoptera, Delphacidae) were examined under a series of experimental conditions in the laboratory. The sucking rate increased with the age of the planthopper. The relative sucking rate of nymphs at the 1st, 2nd, 3rd, 4th, and 5th instars and macropterous male adult was 0.19, 0.27, 0.37, 0.49, 0.59, 0.69, and 1 of that of macropterous female adult (set as standard insect [SI]), respectively. The SI sucked at a maximum rate from rice plants at tillering stage. In indica rice varieties, the SI had higher sucking rate than in japonica varieties. The effect of temperature on sucking rate could be described by an exponential quadratic equation. A power equation (W = 0.0001S1.8107) could be used to transfer the relative sucking rate in area (S, mm2) of honeydew excreted by WBPH into absolute dry mass weight (W, mg). The relationship between injury to rice by WBPH in cage and yield loss assessment showed that yield loss was mainly caused by decreased filling percentage of kernels and kernel weights rather than the number of panicles and spikelets per panicle. Finally, experimental results were integrated to a formula that links percentage of yield loss and sucking equivalence of WBPH.
Partial agonistic activity of labetalol, the arylethanolamine, on β3‐adrenoceptors in the guinea‐pig gastric fundus
Authors: Horinouchi T. , Asai S. , Fukushima M. , Koike K.
Published: March 2003

Summary 1 The agonistic and antagonistic effects of labetalol, the α1‐ and β‐adrenoceptor antagonist, were studied on β3‐adrenoceptors in the guinea‐pig gastric fundus.

2 Labetalol caused a concentration‐dependent relaxation with a pD2 value of 5.58 ± 0.09 and an intrinsic activity of 0.64 ± 0.06, which was not affected by pretreatment with both the selective β1‐adrenoceptor antagonist, (±)‐atenolol (100 μM), and the selective β2‐adrenoceptor antagonist, (±)‐butoxamine (100 μM).

3 However, the non‐selective β1‐, β2‐ and β3‐adrenoceptor antagonist, (±)‐bupranolol (3–30 μM), shifted the concentration–response curve of labetalol to the right (pA2 value=5.97 ± 0.08).

4 In the presence of (±)‐atenolol (100 μM) and (±)‐butoxamine (100 μM), relaxations to catecholamines [(−)‐isoprenaline, (−)‐noradrenaline and (−)‐adrenaline], to the selective β3‐adrenoceptor agonist, BRL37344, and to the non‐conventional partial β3‐adrenoceptor agonist, (±)‐CGP12177A, were weakly antagonized by labetalol (10 μM).

5 These results indicate that labetalol, the arylethanolamine, acts as a partial agonist on β3‐adrenoceptors in the guinea‐pig gastric fundus.
Endothelium‐dependent relaxation in isolated renal arteries of diabetic rabbits
Authors: Yousif M. H. M. , Cherian A. , Oriowo M. A.
Published: March 2003

1 In this study, we have investigated the vasodilator response to acetylcholine under diabetes conditions in isolated renal arteries of rabbits. We have also examined the contribution of endothelium‐derived nitric oxide (EDNO) and endothelium‐derived hyperpolarizing factor (EDHF) to the endothelium‐dependent relaxation caused by acetylcholine in the renal arteries of alloxan‐induced diabetic rabbits.

2 Acetylcholine (10−10−10−4 m) produced cumulative concentration–response curve in the renal arteries of both control and diabetic rabbits. The EC50 values and maximal responses to acetylcholine were not significantly different relative to diabetic conditions. In order to isolate the EDHF component of acetylcholine‐induced vasodilator response, l‐nitro‐methyl arginine ester (l‐NAME, 10−4 m) and indomethacin (10−6 m) were added to the Krebs' solution throughout the experiment. Under these conditions, acetylcholine induced vasodilatation in the isolated renal arteries from both control and diabetic rabbits. The vasodilator response to acetylcholine was not affected under diabetic conditions.

3 Sodium nitroprusside (SNP)‐induced relaxation was increased in the diabetic rabbits compared with the control animals.

4 Tetrabutyl ammonium (TBA, 0.5 mm) produced a significant reduction in acetylcholine‐induced vasodilatation in both preparations from control and diabetic animals, consistent with involvement of K+ channels in mediating this response. Glibenclamide (1 μm) attenuated acetylcholine‐induced vasodilatation in preparations from control animals only, while iberiotoxin (0.05 μm) significantly reduced the vasodilator response to acetylcholine in preparations from both control and diabetic animals.

5 The role of EDNO in mediating acetylcholine‐induced vasodilatation was examined. The vascular preparations were incubated with 20 mm K+‐Krebs' solution to inhibit the EDHF contribution to acetylcholine‐induced vasodilatation. Under this condition, acetylcholine induced a vasodilator response in both preparations from control and diabetic rats. Pretreatment with l‐NAME (10−4 m) attenuated acetylcholine‐induced vasodilatation in both preparations, indicating an nitric oxide‐mediated vasodilator response.

6 Our results indicated that acetylcholine‐induced vasodilatation in the isolated renal arteries of alloxan‐induced diabetic rabbits was not affected under diabetic conditions. Acetylcholine‐induced vasodilatation is mediated by two vasodilator components; namely, EDHF and EDNO. The contribution of EDHF and EDNO to acetylcholine‐induced vasodilatation was not affected under diabetic conditions and there was no indication of endothelial dysfunction associated with diabetes. EDHF component was found to act mainly through high conductance Ca2+‐activated K+ channels under normal and diabetic conditions, while the adenosine triphosphate‐dependent K+ channels were involved in mediating acetylcholine vasodilator response in the control preparations only.
Inhibitory effects of cortical steroids and adrenocorticotropic hormone on catecholamine secretion in guinea‐pig perfused adrenal glands
Authors: Yonekubo K. , Ohta T. , Nakazato Y. , Ito S.
Published: March 2003

1 We investigated the effects of exogenously applied steroids and endogenously released cortisol on catecholamine (CA) secretion induced by cholinergic agonists in perfused guinea‐pig adrenal glands.

2 Acetylcholine (ACh) and electrical stimulation induced CA secretion, which was reversibly inhibited by cortisol. Adrenocorticotropic hormone (ACTH) increased the concentration of cortisol in the perfusion effluent and partly inhibited the secretory response to ACh.

3 Cortisol or aldosterone dose‐dependently inhibited secretory responses to nicotine and muscarine. These inhibitory effects were not antagonized by mifepristone and spironolactone, respective cortisol and aldosterone receptor blockers.

4 Dexamethasone, cortisone, corticosterone, 11‐deoxycortisol, 11‐deoxycorticosterone, prednisolone and cholesterol inhibited nicotine‐evoked CA secretion. The secretory response to muscarine was inhibited by these compounds except for dexamethasone and prednisolone.

5 Dexamethasone, cortisol and aldosterone had no effect on CA secretion induced by high KCl.

6 These results suggest that steroids affect nicotinic and muscarinic ACh receptor‐mediated responses through distinct mechanisms, and that cortisol released from the adrenal cortex inhibits CA secretion from the adrenal medulla.
The effects of hypochlorite‐induced oxidative stress on presynaptic M2‐receptors at sympathetic nerve endings in the rat tail artery
Authors: Sand C. , Peters S. L. M. , Mathy M.‐J. , Pfaffendorf M. , Van Zwieten P. A.
Published: March 2003

Summary 1 It was shown recently that stimulation of cardiac muscarinic M2‐receptors revealed an enhanced negative inotropic response in isolated rat left atria after exposure to hypochlorite‐induced oxidative stress. This phenomenon was not observed after stimulation of the cardiac A1‐receptor, which like the M2‐receptor is coupled to Gi‐proteins. Since even the contractile response to M3‐receptor stimulation was not amplified in the rat portal vein, we hypothesized a M2‐receptor specificity of this hypochlorite‐induced enhancement.

2 The present study was performed in order to investigate whether the sympathoinhibitory response to presynaptically located M2‐receptor stimulation would also be modified after exposure to hypochlorite in the rat tail artery. We applied electrical field stimulation (EFS) in order to mimic sympathetic neurotransmission.

3 EFS increased the vascular tone frequency‐dependently (0.3–4 Hz). EFS‐induced vasoconstriction could be attenuated by acetylcholine (30 nm−1 μm) in a concentration‐dependent manner. Hypochlorite (10 and 100 μm) did not affect the sympathoinhibitory effect of acetylcholine (100 nm).

4 In conclusion, in contrast to cardiac M2‐receptors, hypochlorite did not amplify the sympathoinhibitory effects of presynaptic M2‐receptors. The different responsiveness between neuronal and cardiac M2‐receptors to hypochlorite may be explained by the different G‐protein subunits involved in the activation of the underlying signalling cascade.
Evidence that the hypotensive effect of WAY 100635, a 5‐HT1A receptor antagonist, is related to vascular α1‐adrenoceptor blockade in the adult rat
Authors: Villalobos‐Molina R. , López‐Guerrero J. J. , Gallardo‐Ortíz I. A. , Ibarra M.
Published: March 2003

1 The effect of WAY100635 (N‐[2‐[4‐(2‐methoxyphenyl)‐1‐piperazinyl]ethyl]‐N‐(2‐pyridinyl) cyclohexanecarboxamide trihydrochloride), a 5‐HT1A receptor antagonist, on cardiovascular function was studied.

2 The i.v. injection of WAY100635 dose‐dependently decreased blood pressure in anaesthetized rats; while in pithed rats WAY100635 (1 mg  kg−1) displaced the phenylephrine pressor effect.

3 WAY100635 antagonized phenylephrine‐induced contraction in rabbit and rat aorta (pA2 of 6.88 and 7.93 and Schild slopes of −0.83 and −1.21, respectively); while in rat caudal artery pKB was 7.45 and the Schild slope of −0.56, suggesting a complex interaction in this vessel.

4 The results show that WAY100635 induced hypotension in the anaesthetized rat and suggest that this effect could be partially explained by antagonism of vascular α1‐adrenoceptors.
Muscarinic receptors of the urinary bladder: detrusor, urothelial and prejunctional
Authors: Chess‐Williams R.
Published: March 2003

1 The parasympathetic nervous system is responsible for maintaining normal bladder function, contracting the bladder smooth muscle (detrusor) and relaxing the bladder outlet during micturition.

2 Contraction of the bladder involves direct contraction via M3 receptors and an indirect ‘re‐contraction’ via M2‐receptors whereby a reduction in adenylate cyclase activity reverses the relaxation induced by β‐adrenoceptor stimulation.

3 Muscarinic receptors are also located on the epithelial lining of the bladder (urothelium) where they induce the release of a diffusible factor responsible for inhibiting contraction of the underlying detrusor smooth muscle. The factor remains unidentified but is not nitric oxide, a cyclooxygenase product or adenosine triphosphate.

4 Finally, muscarinic receptors are also located prejunctionally in the bladder on cholinergic and adrenergic nerve terminals, where M1‐receptors facilitate transmitter release and M2 or M4‐receptors inhibit transmitter release.

5 In pathological states, changes may occur in these receptor systems resulting in bladder dysfunction. Muscarinic receptor antagonists are the main therapeutic agents available for treatment of the overactive bladder, but whether their therapeutic effect involves actions at all three locations (detrusor, prejunctional, urothelial) has yet to be established.
Characterization of adenosine receptors mediating the vasodilator effects of adenosine receptor agonists in the microvasculature of the hamster cheek pouch in vivo
Authors: Nicholls J. , Hourani S. M. O. , Hall J. M.
Published: March 2003

1 The aim of this study was to characterize the adenosine receptor mediating vasodilation in the microvasculature of the hamster cheek pouch in vivo. A range of adenosine agonists was used including N6‐cyclopentyladenosine (CPA) (A1 agonist), 5′‐N‐ethylcarboxamidoadenosine (NECA) (non‐selective), 2‐chloroadenosine (2CADO) (non‐selective), 2‐p‐(2‐carboxyethyl)‐phenethylamino‐5′‐N‐ethylcarboxamidoadenosine (CGS 21680) (A2A agonist), N6‐(3‐iodobenzyl)‐adenosine‐5′‐N‐methyluronamide (IBMECA) (A3 agonist) and adenosine, as well as the adenosine antagonists 8‐sulphophenyltheophylline (8‐SPT) (A1/A2 antagonist), 1,3‐dipropyl‐8‐cyclopentylxanthine (DPCPX) (A1 antagonist) and 4‐(2‐[7‐amino‐2‐(2‐furyl)[1,2,4]‐triazolo[2,3‐a][1,3,5]triazin‐5‐ylamino]ethyl)phenol (ZM 241385) (A2A antagonist).

2 All the adenosine analogues used induced vasodilation at concentrations between 10 nm and 1 μm, and the potency order was NECA > CGS 21680 > 2CADO > CPA=IBMECA >> adenosine, indicating an action at A2A receptors. 8‐SPT (50 μm) antagonized vasodilator responses to NECA with an apparent pKB of 5.4, consistent with an action at A1 or A2 receptors and confirming that A3 receptors are not involved in this response.

3 DPCPX (10 nm) had no effect on vasodilation evoked by NECA, suggesting that this response was not mediated via A1 receptors, while ZM 241385 (10 nm) antagonized dilator responses to NECA with an apparent pKB of 8.9 consistent with an action via A2A receptors.

4 Overall these results suggest that adenosine A2A receptors mediate vasodilation in the hamster cheek pouch in vivo.
Control of non‐adrenergic non‐cholinergic reflex motor responses in circular muscle of guinea‐pig small intestine by Met‐enkephalin
Authors: Ivancheva Chr. , Radomirov R.
Published: March 2003

1 A triple organ bath method allowing the synchronous recording of the motor activity of the circular muscle layer belonging to the oral and anal segments of guinea‐pig small intestine adjacent to an electrically stimulated middle segment was developed to study the ascending and descending reflex motor responses.

2 Electrical field stimulation (0.8 ms, 40 V, 5 Hz, 10 s) applied to the middle part of the segments elicited tetrodotoxin (1 μm)‐sensitive ascending and descending contractile responses of the nonstimulated parts, oral and anal, respectively. The ascending contraction was more pronounced as compared with the descending contraction.

3 In the presence of phentolamine (5 μm), propranolol (5 μm) and atropine (3 μm) a significant decrease in the amplitude of the ascending contraction was seen and a descending relaxation, instead of a contraction was observed.

4 Met‐enkephalin applied at a single concentration (0.1 μm) or cumulatively (0.001–1 μm) inhibited both non‐adrenergic non‐cholinergic (NANC) descending relaxation and ascending contraction with similar efficacy but different potency, IC50 being 5.9 ± 0.3 and 39.0 ± 4 nm, respectively. Naloxone (0.5 μm) prevented the effects of Met‐enkephalin.

5 L‐NNA (0.5 mm), an inhibitor of nitric oxide synthesis, increased the ascending contraction and strongly reduced but not abolished the descending relaxation. l‐Arginine (0.5 mm) restored the motor responses to the initial level in l‐NNA‐pretreated preparations, d‐Arginine (0.5 nm) had no effects.

6 Met‐enkephalin (0.1 μm) depressed the l‐NNA‐dependent increase of the ascending contraction and failed to change the l‐NNA‐resistant part of the descending relaxation.

7 Met‐enkephalin did not alter spontaneous NANC mechanical activity. SNP (1 or 10 μm), an exogenous donor of nitric oxide, caused a concentration‐dependent relaxation. The effects of SNP persisted in Met‐enkephalin (0.1 μm)‐pretreated preparations.

8 NANC reflex ascending contraction and descending relaxation were synchronously induced by a local nerve stimulation indicating a functional coactivation of NANC orally projected excitatory and anally directed inhibitory pathways. Acting prejunctionally, Met‐enkephalin provided a negative controlling mechanism inhibiting both ascending and descending, mainly nitric oxide mediated, reflex responses. A higher sensitivity of the descending relaxation to Met‐enkephalin was observed suggesting an essential role of opioid(s) in reducing the efficacy of descending motor activity.
Mitochondrial dysfunction leads to telomere attrition and genomic instability
Authors: Liu Lin , Trimarchi James R. , Smith Peter J. S. , Keefe David L.
Published: March 2003

Mitochondrial dysfunction and oxidative stress have been implicated in cellular senescence, apoptosis, aging and aging‐associated pathologies. Telomere shortening and genomic instability have also been associated with replicative senescence, aging and cancer. Here we show that mitochondrial dysfunction leads to telomere attrition, telomere loss, and chromosome fusion and breakage, accompanied by apoptosis. An antioxidant prevented telomere loss and genomic instability in cells with dysfunctional mitochondria, suggesting that reactive oxygen species are mediators linking mitochondrial dysfunction and genomic instability. Further, nuclear transfer protected genomes from telomere dysfunction and promoted cell survival by reconstitution with functional mitochondria. This work links mitochondrial dysfunction and genomic instability and may provide new therapeutic strategies to combat certain mitochondrial and aging‐associated pathologies.
Spatio‐temporal analysis of gene expression during aging in Drosophila melanogaster
Authors: Seroude Laurent , Brummel Ted , Kapahi Pankaj , Benzer Seymour
Published: March 2003

The relationship between gene expression and the regulation of longevity is poorly understood. Previous studies focusing on microarray or tissue‐specific changes in gene expression as a function of age have provided evidence that gene expression is a dynamic process which is regulated, even late in an organism's lifespan. Using the enhancer‐trap technique, a systematic analysis of the spatio‐temporal regulation of gene expression in tissues of adult Drosophila is presented. As many as 80% of enhancer traps analysed displayed (some form of) transcriptional change with age. In some cases the rate of change in expression was found to correlate with changes in longevity under various conditions, suggesting that they may be indicators of ‘physiological age’ and therefore valuable markers for dissecting the aging process. Molecular analysis of enhancer traps that showed increased activity with age was performed to identify candidate genes that may be important in the regulation of longevity; we identified changes in reporters associated with immunity, microtubule organization and muscle function.
The role of chondrocyte senescence in osteoarthritis
Authors: Price Jo S. , Waters Jasmine G. , Darrah Clare , Pennington Caroline , Edwards Dylan R. , Donell Simon T. , Clark Ian M.
Published: March 2003

Replicative senescence occurs when normal somatic cells stop dividing. Senescent cells remain viable, but show alterations in phenotype, e.g. altered expression of matrix metalloproteinases (MMPs); these enzymes are known to be involved in cartilage destruction. It is assumed that cells deplete their replicative potential during aging, and age is a major risk factor for osteoarthritis (OA). Therefore, we hypothesized that chondrocytes in aging or diseased cartilage become senescent with associated phenotypic changes contributing to development or progression of OA.

Articular cartilage was obtained from OA patients undergoing arthroplasty, with ‘normal’ cartilage from trauma surgery for hip fracture. Senescent cells were identified using the senescence‐associated β‐galactosidase (SA‐β‐gal) marker. Telomere length was assessed using Southern blot. MMP expression was measured at the mRNA level using Taqman® RT‐PCR.

No SA‐β‐gal staining was observed in control cartilage regardless of patient age. In contrast, SA‐β‐gal staining was observed in damaged OA cartilage adjacent to the lesion. Cultured chondrocytes isolated from sites near a lesion contained a greater percentage of SA‐β‐gal positive cells than cultures isolated from distal sites or normal cartilage. Mean telomere length was shorter in cells near the lesion compared to distal sites in the same joint; thus the former population has undergone cell division. The expression of collagenases MMP‐1, ‐8 and ‐13 and tissue inhibitor of metalloproteinases (TIMP)‐1 was altered in OA cartilage, but no difference was detected between lesion and distal sites in the same joint (i.e. no correlation was found between senescent cells and proteinase/inhibitor expression).
Age‐specific metabolic rates and mortality rates in the genusDrosophila
Authors: Promislow Daniel E. L. , Haselkorn Tamara S.
Published: March 2003

Early theories of aging suggested that organisms with relatively high metabolic rates would live shorter lives. Despite widespread tests of this ‘rate of living’ theory of aging, there is little empirical evidence to support the idea. A more fine‐grained approach that examined age‐related changes in metabolic rate over the life span could provide valuable insight into the relationship between metabolic rate and aging. Here we compare age‐related metabolic rate (measured as CO2production per hour) and age‐related mortality rate among five species in the genusDrosophila. We find no evidence that longer‐lived species have lower metabolic rates. In all five species, there is no clear evidence of an age‐related metabolic decline. Metabolic rates are strikingly constant throughout the life course, with the exception of females ofD. hydei, in which metabolic rates show an increase over the first third of the life span and then decline. We argue that some physiological traits may have been shaped by such strong selection over evolutionary time that they are relatively resistant to the decline in the force of selection that occurs within the life time of a single individual. We suggest that comparisons of specific traits that do not show signs of aging with those traits that do decline with age could provide insight into the aging process.
A call to fins! Zebrafish as a gerontological model
Authors: Gerhard Glenn S. , Cheng Keith C.
Published: March 2003

Among the wide variety of model organisms commonly used for studies on aging, such as worms, flies and rodents, a wide research gap exists between the invertebrate and vertebrate model systems. In developmental biology, a similar gap has been filled by the zebrafish (Danio rerio). We propose that the zebrafish is uniquely suited to serve as a bridge model for gerontology. With high fecundity and economical husbandry requirements, large populations of zebrafish may be generated quickly and cheaply, facilitating large‐scale approaches including demographic studies and mutagenesis screens. A variety of mutants identified in such screens have led to modelling of human disease, including cardiac disorders and cancer. While zebrafish longevity is at least 50% longer than in commonly used mouse strains, as an ectothermic fish species, its life span may be readily modulated by caloric intake, ambient temperature and reproductive activity. These features, coupled with a growing abundance of biological resources, including an ongoing genome sequencing project, make the zebrafish a compelling model organism for studies on aging.
The true face of JNK activation in apoptosis
Authors: Lin Anning , Dibling Benjamin
Published: March 2003

Age‐associated changes in apoptotic rates have been observed in a number of different tissues. While the implications of these findings remain unclear, a better understanding of how apoptosis is regulated may further our understanding of the aging process. The role of the JNK pathway in apoptosis has been highly controversial with studies suggesting that it plays a pro‐apoptotic, anti‐apoptotic or no role in this process. Here we discuss what is currently known about JNK's role in apoptosis, highlighting recent findings regarding NF‐κB‐mediated inhibition of JNK activation and its impact on TNF‐α induced apoptosis.
The influence of metabolic rate on longevity in the nematode Caenorhabditis elegans*
Authors: Van Voorhies Wayne A.
Published: March 2003

Much of the recent interest in aging research is due to the discovery of genes in a variety of model organisms that appear to modulate aging. A large amount of research has focused on the use of such long‐lived mutants to examine the fundamental causes of aging. While model organisms do offer many advantages for studying aging, it also critical to consider the limitations of these systems. In particular, ectothermic (poikilothermic) organisms can tolerate a much larger metabolic depression than humans. Thus, considering only chronological longevity when assaying for long‐lived mutants provides a limited perspective on the mechanisms by which longevity is increased. In order to provide true insight into the aging process additional physiological processes, such as metabolic rate, must also be assayed. This is especially true in the nematode Caenorhabditis elegans, which can naturally enter into a metabolically reduced state in which it survives many times longer than its usual lifetime. Currently it is seen as controversial if long‐lived C. elegans mutants retain normal metabolic function. Resolving this issue requires accurately measuring the metabolic rate of C. elegans under conditions that minimize environmental stress. Additionally, the relatively small size of C. elegans requires the use of sensitive methodologies when determining metabolic rates. Several studies indicating that long‐lived C. elegans mutants have normal metabolic rates may be flawed due to the use of inappropriate measurement conditions and techniques. Comparisons of metabolic rate between long‐lived and wild‐type C. elegans under more optimized conditions indicate that the extended longevity of at least some long‐lived C. elegans mutants may be due to a reduction in metabolic rate, rather than an alteration of a metabolically independent genetic mechanism specific to aging.
Neural control of aging skeletal muscle
Authors: Delbono Osvaldo
Published: March 2003

Functional and structural decline in the neuromuscular system with aging has been recognized as a cause of impairment in physical performance and loss of independence in the elderly. Alterations in spinal cord motor neurones and at the neuromuscular junction have been identified as evidence of denervation in skeletal muscles from aging mammals, including humans. However, the reciprocal influences of neurones on gene expression in muscle and of muscle on age‐related neurodegeneration are poorly understood, and, as a result, interventions aimed at delaying or preventing degeneration of the neural component in aging muscle have been largely unsuccessful. The present article discusses the evidence for neural influence on age‐related impairments of skeletal muscle, including a role in excitation–contraction uncoupling. The role of nerves in regulating the trophic actions of insulin‐like growth factor‐1 (IGF‐1) and other neurotrophic factors is considered as a novel influence on the effects of aging on the neuromuscular junction. A better understanding of nerve–muscle interactions will allow for more rational interventions in the aging neuromuscular system.
Are gonadal steroid hormones involved in disorders of brain aging?
Authors: Azcoitia Iñigo , DonCarlos Lydia L. , Garcia‐Segura Luis M.
Published: March 2003

Human aging is associated with a decrease of circulating gonadal steroid hormones. Since these hormones act as trophic factors for neurones and glia, it is possible that the decrease in sex steroid levels may contribute to the increased risk of neurodegenerative disorders with advanced age. Sex steroids are neuroprotective in several animal models of central and peripheral neurodegenerative diseases, and clinical data suggest that these hormones may reduce the risk of neural pathology in aged humans. Potential therapeutic approaches for aged‐associated neural disorders may emerge from studies conducted to understand the mechanisms of action of sex steroids in the nervous system of aged animals. Alterations in the endogenous capacity of the aged brain to synthesize and metabolize sex steroids, as well as possible aged‐associated modifications in the signalling of sex steroid receptors in the nervous system, are important areas for future investigation.
Can Midwives Reduce Postpartum Psychological Morbidity? A Randomized Trial
Authors: Lavender Tina , Walkinshaw Stephen A. ,   Tina Lavender is a Research Midwife and Stephen Walkinshaw is a Consultant in Feto‐Maternal Medicine at the Liverpool Women’s Hospital, Merseyside, England.
Published: March 2003

Background:
Women who are traumatized after childbirth find that listening, support, counseling, understanding, and explanation are the most useful treatments. However, little evidence is available from randomized trials of the relative efficacy of these treatments as a positive postnatal intervention. This study purpose was to examine if postnatal ‘‘debriefing’’ by midwives can reduce psychological morbidity after childbirth.
Method:
A randomized trial was conducted in a regional teaching hospital in northwest England. One hundred and twenty postnatal primigravidas were allocated by sealed envelopes to receive the debriefing intervention (n= 56) or not (n= 58). The main outcome measure was the Hospital Anxiety and Depression (HAD) scale administered by postal questionnaire 3 weeks after delivery. The proportion of women in each group with anxiety and depression scores of more than 10 points were compared, using odds ratios and 95% confidence intervals.Results:Women who received the intervention were less likely to have high anxiety and depression scores after delivery when compared with the control group.Conclusions:The support, counseling, understanding, and explanation given to women by midwives in the postnatal period provides benefits to psychological well‐being. Maternity units have a responsibility to develop a service that offers all women the option of attending a session to discuss their labor. (BIRTH 25:4 December 1998)
Labor Concerns of Women Two Months After Delivery
Authors: Fowles Eileen R. ,   Eileen Fowles is an Assistant Professor in Maternal‐Child Nursing at Southern Illinois University, School of Nursing, Edwardsville, Illinois.
Published: March 2003

Background:
Women strive to incorporate their labor and delivery experiences into their self‐system as they form an identity as a mother. As part of a larger study examining the development of maternal identity, women were asked to respond to a single open‐ended question—“Is there anything about your labor and delivery that is still bothering you?”—to determine if women experienced any discrepancies between the expectations and realities of their births.
Methods:
A descriptive, qualitative design was applied to examine responses to an open‐ended question from a convenience sample of 77 women from three geographically diverse Midwest hospitals who were nine weeks postpartum. Responses were subjected to content analysis to identify major categories of concerns related to labor and delivery.
Results:
Women expressed positive responses, which related to who helped them in labor and to the context of the experience, and frustrations, which related to pain, negative reactions to health caregivers, lack of control, and lack of knowledge.
Conclusions:
These findings offer direction to health care professionals for making labor and childbirth a positive experience, thus easing the transition to motherhood. (BIRTH 25:4 December 1998)
Synergistic Effect of Released Aspirin/Heparin for Preventing Bovine Pericardial Calcification
Authors: Vasudev Sindhu C. , Chandy Thomas , Sharma Chandra P. , Mohanty Mira , Umasankar P.R.
Published: March 2003

Abstract: Calcification is a frequent cause of the clinical failure of bioprosthetic heart valves fabricated from glutaraldehyde pretreated bovine pericardium (GATBP). Aspirin, a potent antiplatelet drug, and heparin, an anticoagulant, are commonly used for postimplant complications such as thrombosis and thromboembolism. Aspirin and heparin were embedded in chitosan/polyethylene vinylacetate co‐matrix to develop a prolonged release form. The effect of these drugs towards the bioprosthetic calcification was investigated by in vitro and in vivo models. In vitro and in vivo evaluation suggest that the released aspirin/heparin from the co‐matrix had a synergistic effect in inhibiting GATBP calcification. In vivo subcutaneous co‐implantation was performed with PEG‐20,000 grafted bovine pericardium (PEG‐GABP), aspirin, and heparin. Biochemical, histological, and scanning electron microscopic evaluation of retrieved samples demonstrated a significant reduction in calcium deposition and alkaline phosphatase activity on PEG‐GABP compared to GATBP. It seems that the aspirin/heparin combination synergistically inhibits the pericardial calcification in addition to their antithrombotic function.
Apparatus for measuring the contact angles at crystal−solution−vapor interfaces
Authors: McLachlan Dan , Cox Herbert M.
Published: March 2003

This paper describes an apparatus for measuring the contact angle between an air bubble and the underside of a solid surface to which the bubble adheres. This general method of measurement of contact angles replaces the usual sessile drop method. The purpose of submerging a bubble in the liquid is to assure an equilibrium vapor pressure, so that, in case of solutions, the surface concentration does not change during measurement. The apparatus was especially designed to study the interfacial energies between saturated solutions and the various faces of a chosen crystal.
Conversion of a monochromator for absorption coefficient measurement
Authors: Varma S. P.
Published: March 2003

A simple technique is described for optical absorption measurements under various conditions, by converting a grating monochromator to a double-beam instrument.
Secondary fluorescent excitation in the scanning electron microscope: Improved sensitivity of energy dispersive analysis
Authors: Gould R. W. , Healey J. T.
Published: March 2003

The use of secondary fluorescence for x-ray energy spectroscopy in the scanning electron microscope has greatly enhanced both resolution and the lower limit of detection. This note describes a simple secondary fluorescence system. The x-ray energy spectra taken from a stainless steel sample illustrate the advantages of this method.
Instrumentation for handling monomolecular films at an air–water interface
Authors: Fromherz Peter
Published: March 2003

A monolayer trough with two movable barriers and several compartments is described. In addition, a precision multilayer depositing lift, a simplified Langmuir trough, and a technique for isolating monolayers remaining in contact with water are discussed. Various applications of this combined instrumentation in the study of monomolecular films are presented.
Gas conditions after the passage of reflected shock waves and their application to torus-like experiments
Authors: Kasuya K. , Kagaya Y. , Murasaki T.
Published: March 2003

In this article we describe briefly recent results on basic processes concerning a crowbar method utilizing reflected shock waves by a pressure-driven shock tube. After that, we propose an apparatus which is an application of this crowbar technique to a new method for producing plasmas.
Application of microwave Fabry–Perot instrumentation to material testing
Authors: Neelakantaswamy P. S.
Published: March 2003

Measuring nonelectrical quantities, such as the quality parameters of a material under industrial manufacture/processing, by means of a low power microwave Fabry–Perot resonator is described. The merits of this type of instrumentation, as compared to the other types of microwave measuring systems for similar applications, are discussed. Some theoretical results analyzing the test conditions are presented. Experimental results regarding the measurement of moisture content in paper using the present technique are reported.
A simple scattering chamber for measurements of the angular distribution of dissociation products produced by ion impact
Authors: McKnight R. H.
Published: March 2003

A scattering chamber for use in atomic collisions experiments is described which utilizes a simple sliding seal and which has an angular range of 20−160°.
Toxic material catcher for gas guns
Authors: Horning R. R. , Hickman G. L.
Published: March 2003

An assembly for capturing fragments of toxic materials used in plate impact tests is described.
Laboratory optical internal wave gauge
Authors: Powell G. M. , Sheppard D. M.
Published: March 2003

An optical instrument for measuring internal waves at the interface between two fluids in a wave tank is described. The sensor is constructed of acrylic plastic and uses a cadmium sulfide photo−sensitive resistor. This system requires that one of the fluids be transparent.
Pseudo−bridge: a different way to compare resistances
Authors: Borchardt Ildon Guilherme , Holland Lawrence Rozier
Published: March 2003

Four impedances are combined around an operational amplifier to give many of the characteristics of a Wheatstone bridge, but with important differences. Both the input and the output are referred to a common ground, and in some applications linearity is greatly enhanced. Stability considerations which limit the range of usable impedances are discussed.
A procedure for producing smooth bore holes in copper cylinders
Authors: Flint E. B. , Hallock R. B.
Published: March 2003

An extremely simple and inexpensive technique by which holes of uniform bore can be produced in copper is described. Measured uniformity may exceed 2500 Å on a bore diameter of 6.35 mm.
High−precision skimmers for supersonic molecular beams
Authors: Gentry W. Ronald , Giese Clayton F.
Published: March 2003

High−quality skimmers for supersonic molecular beams may be fabricated in a variety of shapes by a method which involves both electroforming and machining operations.