A Comparative GC/MS Analysis of Citrus Essential Oils: Unveiling the Potential Benefits of Herb-Drug Interactions in Preventing Paracetamol-Induced Hepatotoxicity

Our study aimed to test the potential of Citrus oils in protecting against paracetamol (PAR)-induced hepatotoxicity. The essential oils of Pineapple sweet orange (OO), Murcott mandarin (MO), Red grapefruit (GO), and Oval kumquat (KO) were investigated using gas chromatography coupled with mass spectrometry (GC/MS). Twenty-seven compounds were identified, with monoterpene hydrocarbons being abundant class. d-Limonene had the highest percentage (92.98 %, 92.82 %, 89.75 %, and 94.46 % in OO, MO, GO, and KO, respectively). Hierarchical cluster analysis (HCA) and principal components analysis (PCA) revealed that octanal, linalool, germacrene D, and d-limonene were the principal discriminatory metabolites that segregated the samples into three distinct clusters. In vitro antioxidant capacities were ranged from 1.2-12.27, 1.79-5.91, and 235.05-585.28 μM Trolox eq/mg oil for 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic (ABTS), ferric-reducing antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC), respectively. In vivo, citrus oils exhibited a significant reduction in alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and nitric oxide (NO). Additionally, there was an increase in glutathione reductase (GSH), and the liver architecture was nearly normal. Molecular docking revealed that d-limonene exhibited a good inhibitory interaction with cytochrome P450 (CYP450) isoforms 1A2, 3A4, and 2E1, with binding energies of -6.17, -4.51, and -5.61 kcal/mol, respectively.

Taming Food-Drug Interaction Risk: Potential Inhibitory Effects of Citrus Juices on Cytochrome Liver Enzymes Can Safeguard the Liver from Overdose Paracetamol-Induced Hepatotoxicity

Paracetamol overdose is the leading cause of drug-induced hepatotoxicity worldwide. Because of N-acetyl cysteine's limited therapeutic efficacy and safety, searching for alternative therapeutic substitutes is necessary. This study investigated four citrus juices: Citrus sinensis L. Osbeck var. Pineapple (pineapple sweet orange), Citrus reticulata Blanco × Citrus sinensis L. Osbeck (Murcott mandarin), Citrus paradisi Macfadyen var. Ruby Red (red grapefruit), and Fortunella margarita Swingle (oval kumquat) to improve the herbal therapy against paracetamol-induced liver toxicity. UHPLC-QTOF-MS/MS profiling of the investigated samples resulted in the identification of about 40 metabolites belonging to different phytochemical classes. Phenolic compounds were the most abundant, with the total content ranked from 609.18 to 1093.26 μg gallic acid equivalent (GAE)/mL juice. The multivariate data analysis revealed that phloretin 3',5'-di-C-glucoside, narirutin, naringin, hesperidin, 2-O-rhamnosyl-swertisin, fortunellin (acacetin-7-O-neohesperidoside), sinensetin, nobiletin, and tangeretin represented the crucial discriminatory metabolites that segregated the analyzed samples. Nevertheless, the antioxidant activity of the samples was 1135.91-2913.92 μM Trolox eq/mL juice, 718.95-3749.47 μM Trolox eq/mL juice, and 2304.74-4390.32 μM Trolox eq/mL juice, as revealed from 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid, ferric-reducing antioxidant power, and oxygen radical absorbance capacity, respectively. The in vivo paracetamol-induced hepatotoxicity model in rats was established and assessed by measuring the levels of hepatic enzymes and antioxidant biomarkers. Interestingly, the concomitant administration of citrus juices with a toxic dose of paracetamol effectively recovered the liver injury, as confirmed by normal sections of hepatocytes. This action could be due to the interactions between the major identified metabolites (hesperidin, hesperetin, phloretin 3',5'-di-C-glucoside, fortunellin, poncirin, nobiletin, apigenin-6,8-digalactoside, 6',7'-dihydroxybergamottin, naringenin, and naringin) and cytochrome P450 isoforms (CYP3A4, CYP2E1, and CYP1A2), as revealed from the molecular docking study. The most promising compounds in the three docking processes were hesperidin, fortunellin, poncirin, and naringin. Finally, a desirable food-drug interaction was achieved in our research to overcome paracetamol overdose-induced hepatotoxicity.

Effect of Si Content on the Thermal Expansion of Ti15Mo(0-2 Si) Biomaterial Alloys during Different Heating Rates

Thermal expansion measurements were used to characterize phase transformations in metastable β-Ti alloys (Ti15MoxSi) without and with various Si additions (where x = 0, 0.5, 1.0, 1.5, and 2 in wt.%) during linear heating at two heating rates of 5 and 10 °C/min up to 850 °C. For this study, five alloys were developed and examined in terms of their presence phases, microstructures, and starting and final transformation temperatures. According to the results, all of the as-cast samples primarily include an equiaxed β-Ti phase. The influence of phase transformation on the material dimensions was discussed and compared with the variations in Si contents. The transformation was investigated using a dilatometric technique for the developed alloys during continuous heating and cooling. The dilatometric curve of heating revealed two distinct reflection points as the heating temperature increased. The starting transformation temperature (T_s) to obtain the ω-phase was reported at 359 °C without Si addition; whereas the final transformation temperature (T_f) of the dissolution of α-phase was obtained at 572 °C at a heating rate of 10 °C/min. At 2 wt.% Si, the first derivative curves reported T_s and T_f transforming temperatures of 314-565 °C (at a 5 °C/min heating rate) and 270-540 °C (at a 10 °C/min heating rate), respectively. The T_s and T_f transforming temperatures were significantly decreased with Si additions, which decreased the β-transus temperature. Moreover, the thermal expansion coefficient curves of the investigated alloys without and with 2 wt.% Si were studied. The transformation heating curves have an S-shaped pattern, according to the results.

Worn surface topography and mathematical modeling of Ti-6Al-3Mo-2Sn-2Zr-2Nb-1.5Cr alloy

This study aims at investigating worn surface topography and mathematical modeling of annealed Ti-6Al-3Mo-2Sn-2Zr-2Nb-1.5Cr alloy using response surface methodology (RSM). The alloy was subjected to three different regimes in order to study their effect on mechanical properties. First regime was applying cold deformation by compression until 15% drop in height at room temperature. The second regime was performing solution treated on the deformed samples at 920 °C for 15 min then air-cooled (AC) to ambient temperature. Third regime was applying aging on the deformed and solution treated specimen for 4 hr at 590 °C followed by air-cooling. Three different velocities (1, 1.5, and 2 m/s) were adopted to conduct dry sliding wear according to the experimental design technique (EDT). Gwyddion and Matlab softwares were used to detect worn surface photographs analytically and graphically. Maximum hardness of 425 HV₂₀ was obtained for AC+Aging specimen, while minimum hardness of 353 HV₂₀ was reported for the annealed specimen. Applying aging process after solution treatment enhanced considerably the wear property and this enhancement reached 98% as compared to the annealed condition. The relationship between input factors (hardness & velocity) and responses (Abbott Firestone zones) was demonstrated using analysis of variance (ANOVA). The best models for Abbott Firestone zones (high peaks, exploitation, and voids) produced accurate data that could be estimated for saving time and cost. The results showed that the average surface roughness increases with increasing sliding velocity for all conditions except AC+Aging condition where the average surface roughness decreased with increasing sliding velocity. The results revealed that at low velocity and hardness, the material gives the highest exploitation zone (86%). While at high velocity and hardness, the material gives the lowest exploitation zone (70%). In general, the predicted results of mathematical model showed close agreement with experimental results, creating that models could be utilized to predict Abbott Firestone zones satisfactorily.

Influence of Microstructure and Alloy Composition on the Machinability of α/β Titanium Alloys

A comparative study was conducted for the machining of two α/β titanium alloys, namely Ti-6Al-4V (Ti64) and Ti-6Al-7Nb (Ti67), using wire electric discharge machining (WEDM). The influence of cutting speed and cutting mode on the machined surfaces in terms of surface roughness (Ra), recast layer (RL), and micro-hardness have been evaluated. Rough cut (RC) mode at a cutting speed of 50 µm/s resulted in thermal damage; Ra was equal to 5.68 ± 0.44 and 4.52 ± 0.35 µm for Ti64 and Ti67, respectively. Trim-cut mode using seven cuts (TRC-VII) at the same speed decreased the Ra to 1.02 ± 0.20 µm for Ti64 and 0.92 ± 0.10 µm for Ti67. At 100 µm/s, Ra reduced from 2.34 ± 0.28 µm to 0.88 ± 0.12 µm (Ti64), and from 1.42 ± 0.15 µm to 0.90 ± 0.08µm (Ti67) upon changing from TRC-III to TRC-VII. Furthermore, a thick recast layer of 30 ± 0.93 µm for Ti64 and 14 ± 0.68 µm for Ti67 was produced using the rough mode, while TRC-III and TRC-VII modes produced layers of 12 ± 1.31 µm and 5 ± 0.72 µm for Ti64 and Ti67, respectively. Moreover, rough cut and trim cut modes of WEDM played a significant role in promoting the surface hardness of Ti64 and Ti67. By employing the Response Surface Methodology, it was found that the machining mode followed by cutting speed and the interaction between them are the most influential parameters on surface roughness. Finally, mathematical models correlating machining parameters to surface roughness were successfully developed. The results strongly promote the trim-cut mode of WEDM as a promising machining route for two-phase titanium alloys.

Atomic-Scale Insights into the Lateral and Vertical Epitaxial Growth in Two-Dimensional Pd2Se3-MoS2 Heterostructures

Two-dimensional (2D) materials form heterostructures in both the lateral and vertical directions when two different materials are interfaced, but with totally different bonding mechanisms of covalent in-plane to van der Waal's layered interactions. Understanding how the competition between lateral and vertical forces influences the epitaxial growth is important for future materials development of complex mixed layered heterostructures. Here, we use atomic-resolution annular dark-field scanning transmission electron microscopy to study the detailed atomic arrangements at mixed 2D heterostructure interfaces composed of two semiconductors with distinctly different crystal symmetry and elemental composition, Pd₂Se₃:MoS₂, in order to understand the role of different chemical bonds on the resultant epitaxy. Pd₂Se₃ is grown off the step edge in bilayer MoS₂, and the vertical and lateral epitaxial relationships of the Pd₂Se₃-MoS₂ heterostructures are investigated. We find that the similarity of geometry at the interface with one metal (Pd or Mo) atoms bonded with two chalcogens (S or Se) are the crucial factors to make the atomically stitched lateral junction of 2D heterostructures. In addition, the vertical van der Waal interactions that are normally dominant in layered materials can be overcome by in-plane forces if the interfacial atomic stitching is high in quality and low in defect density. This knowledge should help guide the approaches for improving the epitaxy in mixed 2D heterostructures and seamless stitching of in-plane 2D heterostructures with various complex monolayer structures.

Travel during COVID-19 pandemic in Libya: reasons of travel, disease importation and travel regulations

Restriction of mobility between countries is an important regulatory measure to combat pandemics such as the coronavirus disease 2019 (COVID-19). Currently, PCR testing is required to enter the Libyan borders. However, no post-travel quarantine is employed. In this report, we briefly discuss travel regulations in Libya during the COVID-19 pandemic and disease importation by travelers. The results showed that almost half of the sample travel because of health care and therapy reasons. Tunisia was the most visited destination mainly for trading and business and receiving healthcare. Importantly, 13% of asymptomatic travelers were SARS-CoV-2 positive. Issues regarding repeated testing among very frequent travelers and variant importation needs to be addressed in a more efficient manner.

Whole-genome sequencing of SARS-COV-2 showed wide spread of B.1.525 in February 2021 in Libya

Alpha (B.1.1.7) SARS-COV-2 variant was detected in September 2020 in minks and humans in Denmark and UK. This variant has several mutations in the spike region (S) which could increase the transmissibility of the virus 43-90% over previously circulating variants. The National Center for Disease Control (NCDC) announced on 24 February 2021 a 25% frequency of B.1.1.7 strain in Libya using a reverse-transcriptase quantitative PCR assay. This assay relies on the specific identification of the H69-V70 deletion in S gene which causes its failure of amplification (SGTF). This deletion is not specific for B.1.1.7, but is also characteristic of two other SARS-COV-2 variants. This study aimed to estimate the frequency of B.1.1.7 and identify other variants circulating in Libya in February 2021. We performed whole genome sequencing of 67 positive SARS-COV-2 samples collected on 25 February 2021 in Libya which were also tested by RT-qPCR for SGTF. Our results showed that 55% of samples had mutations specific to B.1.525 strain and only ~3% of samples belonged to B.1.1.7. These findings suggested that B.1.525 was spreading widely in Libya. The use of such RT-qPCR assay, although useful to track some variants, cannot discriminate between variants with H69-V70 deletion. RT-qPCR assays could be multiplexed to identify multiple variants and screen samples prior to sequencing. We emphasize on the need for providing whole-genome sequencing to the main COVID-19 diagnostic laboratories in Libya as well as establishing international collaboration for building capacity and advancing research in this time of the pandemic.

Bivalent transition metal complexes of (E)-3-(2-benzylidenehydrazinyl)-3-oxo-N-(p-tolyl)propanamide: Spectroscopic, computational, biological activity studies

Schiff base complexes of Co(II), Ni(II) and Cu(II) with (E)-3-(2-benzylidenehydrazinyl)-3-oxo-N-(p-tolyl)propanamide (H2BHAH) containing N and O donor sites were synthesized. Both ligand and its metal complexes were characterized by elemental analysis, thermal analysis (TG and DTG), spectroscopy ((1)H NMR, IR, UV-visible, MS spectra), and physical measurements (magnetic susceptibility and molar conductance). The kinetic and thermodynamic parameters of the different decomposition steps of some complexes were calculated using the Coats-Redfern and Horowitz-Metzger methods. Also, the DFT studying was evaluated to confirm the geometry of the investigated compounds. Moreover, the association and formation constants of Ni(II) and Cu(II) ions in mixed solvent at 290.15K were calculated by using electrical conductance. The antimicrobial activities of the ligand and its complexes were studied against gram positive bacteria Staphylococcus aureus, gram negative bacteria; Escherichia coli and pathogenic fungi; Candida albicans by using minimum inhibition concentrations method. The antioxidant (ABTS-derived free radical method) and cytotoxic (in vitro Ehrlich Ascites) activities of the isolated compounds were estimated.

Physicochemical studies and biological evaluation on (E)-3-(2-(1-(2-hydroxyphenyl)hydrazinyl)-3-oxo-N-(thiazol-2yl)propanamide complexes

Hydrazone complexes of Co(II), Ni(II), Cu(II), Pd(II), Cd(II), Zn(II) and U(VI)O2 with (E)-3-(2-(1-(2-hydroxyphenyl)hydrazinyl)-3-oxo-N-(thiazol-2yl)propanamide (H2o-HAH) have been synthesized. The complex structure has been elucidated by analysis (elemental and thermal), spectroscopy ((1)H NMR, (13)C NMR, IR, UV-visible, ESR, MS) and physical measurements (magnetic susceptibility and molar conductance). The kinetic and thermodynamic parameters for the different decomposition steps of some complexes have been calculated using the Coats-Redfern equation. Also, the association and formation constants of Co(II) ion in absolute ethanol solutions at 294.15K have been calculated by using electrical conductance. Moreover, the ligand and its complexes have been screened for their antibacterial (Escherichia coli and Clostridium sp.) and antifungal activities (Aspergillus sp. and Stemphylium sp.) by MIC method.

Co(II), Cd(II), Hg(II) and U(VI)O₂ complexes of o-hydroxyacetophenone[N-(3-hydroxy-2-naphthoyl)] hydrazone: physicochemical study, thermal studies and antimicrobial activity

The o-Hydroxy acetophenone [N-(3-hydroxy-2-naphthoyl)] hydrazone (H(2)o-HAHNH) has been prepared and its structure is confirmed by elemental analysis, IR, (1)H NMR and (13)C NMR spectroscopy. It has been used to produce diverse complexes with Co(II), Cd(II), Hg(II) and U(VI)O(2) ions. The isolated complexes have been investigated by elemental analysis, magnetic measurements, molar conductivity, thermal (TG, DTG) and spectral ((1)H NMR, (13)C NMR, IR, UV-visible, MS) studies. Infrared spectra suggested H(2)o-HAHNH acts as a bidentate and/or tridentate ligand. The electronic spectrum of [Co(Ho-HAHNH)(2)] complex as well as its magnetic moments suggesting octahedral geometry around Co(II) center. The TG analyses suggest high stability for most complexes followed by thermal decomposition in different steps. Moreover, the kinetic and thermodynamic parameters (Ea, A, ΔH, ΔS and ΔG) for the different decomposition steps of the [Co(Ho-HAHNH)(2)] and [Cd(Ho-HAHNH)(2)] complexes were calculated using the Coats-Redfern and Horowitz-Metzger methods. Moreover, the antibacterial and antifungal activities of the isolated compounds were studied using a wide spectrum of bacterial and fungal strains.

Bivalent transition metal complexes of o-hydroxyacetophenone [N-(3-hydroxy-2-naphthoyl)] hydrazone: spectroscopic, antibacterial, antifungal activity and thermogravimetric studies

Schiff base complexes of Cu(II), Ni(II) and Zn(II) with the o-hydroxyacetophenone [N-(3-hydroxy-2-naphthoyl)] hydrazone (H(2)o-HAHNH) containing N and O donor sites have been synthesized. Both ligand and its metal complexes were characterized by different physicochemical methods, elemental analysis, molar conductivity ((1)H NMR, (13)C NMR, IR, UV-visible, ESR, MS spectra) and also thermal analysis (TG and DTG) techniques. The discussion of the outcome data of the prepared complexes indicates that the ligand behave as a bidentate and/or tridentate ligand. The electronic spectra of the complexes as well as their magnetic moments suggest octahedral geometries for all isolated complexes. The room temperature solid state ESR spectrum of the Cu(II) complex shows d(x2-y2) as a ground state, suggesting tetragonally distorted octahedral geometry around Cu(II) centre. The molar conductance measurements proved that the complexes are non-electrolytes. The kinetic thermodynamic parameters such as: E(#), ΔH(#), ΔG(#), ΔS(#) are calculated from the DTG curves, for the [Ni(H(O)-HAHNH)(2)] and [Zn(H(2O)-HAHNH)(OAc)(2)]·H(2)O complexes using the Coats-Redfern equation. Also, the antimicrobial properties of all compounds were studied using a wide spectrum of bacterial and fungal strains. The [Cu(Ho-HAHNH)(OAc)(H(2)O)(2)] complex was the most active against all strains, including Aspergillus sp., Stemphylium sp. and Trichoderma sp. Fungi; E. coli and Clostridium sp. Bacteria.

Secondary metabolites and bioactivities of Myrtus communis

BACKGROUND

Myrtus species are characterized by the presence of phenolic acids, flavonoids, tannins, volatile oils and fatty acids. They are remedies for variety of ailments. This study therefore investigated medicinal effects of Myrtus communis L.

METHODS

Bioactivity studies of Myrtus communis L. leaves were carried out on volatile oil, 7% methanol and aqueous extracts and the isolated compounds myricetin 3-O-β-glucopyranoside, myricetin 3-O-∝-rhamnopyranoside and gallic acid.

RESULTS

Determination of the median lethal dose (LD(50)) revealed that the volatile oil, alcoholic and aqueous extracts were practically nontoxic and highly safe as no lethality was observed. The tested materials (volatile oil, alcoholic and aqueous extracts, myricetin 3-O-β-glucopyranoside, myricetin 3-O-∝-rhamnopyranoside and gallic acid) showed significant antihyperglycemic, anti-inflammatory and antinociceptive effects as compared with control groups and reference drugs.

CONCLUSION

Administration of extracts of M. communis leaves could be safe at the dose used in this study.

Selection on MHC-linked microsatellite loci in sheep populations

Microsatellites within the major histocompatibility complex (MHC) region have received increasing attention as proxy measures of the level of polymorphism at the Mhc genes themselves. We assessed the diversity of microsatellite loci within or in close proximity of the Mhc genes in several breeds of domestic sheep (Ovis aries) and the wild Mouflon (Ovis orientalis musimon). This was compared to variation at other microsatellite loci scattered throughout the sheep genome. Significantly higher number of alleles were observed at the MHC microsatellites. The sheep breeds studied fell into high- and low-diversity group. This grouping is not related to the agricultural use of the breeds, whether for milk, meat or wool. It is, however, correlated with the geographic origins of the breeds. Southern breeds are genetically more diverse than northern breeds. The observed heterozygosity was in most cases lower than Hardy-Weinberg expectations. The potential impact of selective breeding by man on this is discussed. Neutrality tests indicated that for most of the breeds, the distribution of alleles at the MHC-linked microsatellites are more even than would be expected if the genes were neutral and sampled from populations under drift-mutation equilibrium. Hitchhiking due to tight linkage with alleles at the MHC loci that are under balancing selection is proposed as a possible explanation for this pattern.

Testing for recombination in a short nuclear DNA sequence of the European meadow grasshopper, Chorthippus parallelus

Single-copy nuclear DNA sequences have high potential as a source of genetic markers for population analyses. However, the difficulties that arise when haplotypes that are the product of recombinational rearrangements are present require additional consideration. Two statistical methods for identifying potential recombinants by detecting anomalies in the distribution of variable sites along sequences were used to screen sequences from a single-copy nuclear DNA fragment, cpnl-1, of the European meadow grasshopper (Chorthippus parallelus). Five of the 71 haplotypes in the cpnl-1 data set showed nonrandom distribution of polymorphic sites using both methods. The second method pinpointed an additional four haplotypes. Estimates of the rate of recombination in the entire data set were obtained using standard methods. It is concluded that cpnl-1 haplotypes have been involved in recombination or gene conversion events at a rate more than twice the mutation rate. This confirms that recombination and gene conversion are significant factors in the generation of haplotype variation in nuclear gene sequences. The cpnl-1 haplotypes identified by the tests were present only in populations that have had recent contact; the Balkan and Turkish refugial populations and their post-glacial colonies to the north. This is discussed in relation to the phylogenetic inferences drawn from the same data in a previous report.

Plague dynamics and population genetics of the desert locust: can turnover during recession maintain population genetic structure?

The desert locust (Schistocerca gregaria) undergoes crowding-induced phase transformation from solitary form to gregarious form. The transformations involves changes in behaviour, colour, development, morphometry, fecundity and endocrine physiology. Recession populations of the desert locust exist primarily in the solitary phase as small populations in patchy environments and are prone to extinction because of climatic events. Significant genetic differentiation among recession populations along the Red Sea coast of Eritrea was previously reported. It was hypothesized that despite the mixing effect of recurrent swarms, metapopulation dynamics could have produced genetic divergence among these highly scattered recession populations. A Monte Carlo simulation of the population dynamics of the desert locust in a metapopulation setting, with a realistic range of parameter values clearly demonstrated that this is possible. Population growth was represented by a discrete-time logistic equation. The duration of recessions and swarms was sampled from normal distributions whose means and standard deviations were varied based on reported estimates. An average recession duration of 10 +/- 3 generations and swarm periods half as long but almost twice as variable produced a partitioning of the total genetic variance most similar to that in the empirical study. In conventional metapopulation analysis, whether turnover leads to increased or reduced divergence is dependent on the number of colonists relative to the number of recurrent migrants, and on whether the colonists arise from a single patch or many patches. In the case of locusts, the stochastic boom and bust cycle is the overriding factor. Divergence between patches during recession due to founder effect and recurrent drift is balanced by the high rate of mixing during plagues.

Are recession populations of the desert locust (Schistocerca gregaria) remnants of past swarms?

The desert locust (Schistocerca gregaria) undergoes crowding-induced phase transformation from solitary to gregarious, which involves changes in behaviour, colour, development, morphometry, fecundity and endocrine physiology. During recession, solitary locusts persist in the central, drier part of the species' range in small pocket populations that are prone to extinction. During the intermittent upsurges and the subsequent plagues, gregarious swarms attain huge population size and invade a vast area causing major damage to agriculture. A highly variable nuclear DNA marker, a noncoding 3' end fragment of an antennapedia-class homeobox gene, was screened in locust samples from Eritrea. Despite the homogenizing potential of plague swarms, the last of which was in 1986-89 and originated in this region, the population genetic structure of solitary phase locusts along the Red Sea coast of Eritrea revealed significant divergence. The pattern of divergence indicated that the invasion of the western and northern plains in the summer of 1995 may not, as reported then, have originated in eastern Chad or western Sudan. A number of interrelated hypotheses have been presented to explain the observed genetic heterogeneity between the sampled populations. We conclude, with caution due to the limited sample sizes, that: (i) geographical isolation between breeding sites during plagues and recession; (ii) the marked differences in the flight behaviour of plague swarms and recession populations; (iii) possible failure of gregarious locusts to solitarize and re-establish in recession areas; and (iv) the effect of repeated extinction and recolonization in the meta-population contribute to the maintenance of the genetic structure of recession populations. Potentially productive future research has been identified.

Fine-scale genetic structuring in a natural population of European wild rabbits (Oryctolagus cuniculus)

The genetic structure of a free-living tagged population of European wild rabbits (Oryctolagus cuniculus) was investigated for two consecutive years (1990 and 1991) using 10 polymorphic microsatellite loci. A specific social behaviour, the formation of stable breeding groups, influenced the genetic structure of the population. These breeding groups were shown to constitute genetically differentiated units with low levels of gene flow between them. The average relatedness among members of a social group was higher than within the population as a whole. As a result of female philopatry coupled with male-biased natal dispersal, the relatedness of females was higher than that of males, both within social groups and in the whole population. Furthermore, the average relatedness of females within groups was twice the relatedness of females between groups. This study reveals marked fine-scale, intrapopulation genetic structure, which is attributable to the social behaviour of the European wild rabbit.

mtDNA phylogeography and postglacial patterns of subdivision in the meadow grasshopper Chorthippus parallelus

A 300 bp portion of the mitochondrial cytochrome oxidase subunit I (COI) gene was used to investigate the intraspecific genetic structure of the European meadow grasshopper Chorthippus parallelus. Levels of genetic subdivision between geographical regions in Europe were assessed using the KST statistic and revealed patterns indicative of the postglacial history of this organism. Northern European populations are shown to share a very recent common ancestor with, and hence originate from, a Balkan expansion. Genetic distances between these areas and both southern Italy and central Spain are shown to be approximately equal, even though only the Spanish form is recognized as a distinct subspecies. Distance estimates indicate that the common ancestor of the two subspecies lived more than one glacial cycle ago, and the refugial populations have probably been diverging in isolation for five or six glacial cycles (approximately equal to 550,000 years). Comparisons are made to the analysis of a similar data set using an anonymous nuclear DNA marker (Cooper et al., 1995). Although the structure revealed is generally very similar, differences in the location of transition zones between different genetic forms of C. parallelus may reflect the different historical assortment of these molecules.

The phylogeography of the darkling beetle, Hegeter politus, in the eastern Canary Islands

We investigated the phylogeography of Hegeter politus, a saprophagous, flightless darkling beetle endemic to the eastern Canary Islands, using a fragment of the mitochondrial COI gene. Distance and parsimony based gene trees of the mitotypes identified revealed a striking association between mitotype clades and sampling locations. The branching order of the clades suggested that the colonization of the islands by Hegeter politus proceeded from the southern part of Fuerteventura in a north-northeast direction to Lanzarote and the smaller islands. Based on this, a colonization scenario compatible with the reported geological ages and volcanisms of the various parts of the islands has been proposed. The high divergence of the beetles collected from the extreme south of Fuerteventura (the Jandía peninsula) from all other samples has led us to propose that they may be from a new species that has not been described previously. The ecological isolation of Jandía from the rest of Fuerteventura by the sand dunes that cover its narrow isthmus in the north, and the existence of many plant and animal endemisms unique to Jandía, lend supportive evidence to our proposal. The similarities between the evolution of island endemics in the Hawaiian and Canary archipelagos have been discussed. We conclude that many endemics in the Canary archipelago, like the Hawaiian Islands, are most likely to have originated from post-colonization differentiation and divergence.

Mitochondrial DNA sequence variation and phylogeography of Pimelia darkling beetles on the island of Tenerife (Canary Islands)

Four morphological taxa of the beetle genus Pimelia (Coleoptera, Tenebrionidae) are known to exist on the Atlantic island of Tenerife. We have obtained DNA sequences for 61 individuals from these taxa across the island for a 200 bp long fragment of the mitochondrial COI gene. In addition, a restriction site polymorphism in the nuclear rRNA ITS-1 sequence was identified and screened in a sample of these individuals using the enzyme Kpn2I. The results were analysed using approaches which allow inferences to be made about the population genetic structure and the mitochondrial genealogy of these closely related beetles. The mtDNA haplotype distribution and the estimates of sequence divergence revealed the presence of two ancient mtDNA lineages which coincide with the disjunct volcanic evolution of the island. The ITS-1 polymorphism was found to be diagnostic of these two lineages. However, the morphological and mitochondrial phylogenies were found to be discordant. We argue that this is possibly the result of rapid morphological change, produced by selection in different habitats, which has been recently superimposed on an older mitochondrial DNA divergence.

Role of the hypoglycemic plant extract cleome droserifolia in improving glucose and lipid metabolism and its relation to insulin resistance in fatty liver

In this work the mechanism of the hypoglycemic effect of the plant Cleome-Droserifolia (C.d.) was studied in a group of albino rats rendered glucose intolerant by tetracycline (T.) induced fatty liver, and compared with a normal control (C.) rats. The plant extract significantly suppressed the rise in peripheral blood glucose concentrations, both in the basal (fasting) state and after glucose intake. Suppression of basal blood glucose indicated a lowering effect of the plant extract on hepatic glucose output (HGO). The postprandial hypoglycemic effect of the plant extract without increasing insulin secretion was explained by; First: Potentiation of peripheral and hepatic insulin sensitivity. Second: by diminishing intestinal glucose absorption, which was evident by blunting plasma glucose levels throughout the oral glucose challenge. This plant might prove to have a promising therapeutic value in the treatment of diabetes mellitus, for besides its postprandial hypoglycemic effect, its suppression to hepatic glucose output in the fasting state is a beneficial therapeutic finding in favour of the plant as insulin is the most important drug that brings about this effect. The plant has also got a hypocholesterolemic effect more specifically on low density lipoprotein cholesterol (LDL-C) which consequently raised the high density lipoprotein cholesterol/low density lipoprotein cholesterol (HDL-C/LDL-C) ratio. This adds to its value as a protective and antiatherogenic agent.

Mechanism of insulin resistance and hyper-insulinemia in fatty liver

Hyperinsulinemia and insulin resistance are common features seen in most liver diseases. The present study was carried out on an experimental model of fatty liver (tetracycline induced) in albino rats. Significantly elevated levels of both peripheral plasma insulin and plasma glucose concentrations were recorded in both the fasting state and after an oral glucose intake in the tetracycline-treated rats. The presence of hyperinsulinemia accompanying hyperglycemia is considered a sign of insulin resistance. Peripheral insulin resistance has been proved in this work by the reduced "A" value which refer to the peripheral insulin activity (sensitivity) in fatty liver rats compared to normal rats. The hyperinsulinemia recorded here was due to pancreatic hypersecretion and not a result of reduced hepatic degradation. Hypersecretion of insulin was clearly determined by measuring the level of immunoreactive insulin (IRI) in pancreatic vein which exhibited a significant rise in tetracycline-treated rats, and there was a positive correlation between the pancreatic venous and peripheral venous insulin in the basal state and after 30 min. of oral glucose administration. Hepatic degradation of insulin was not a cause as evidenced by First: the amount of insulin secreted and insulin consumed were significantly higher in fatty liver rats than normal controls. Second: the whole body extraction ratio or insulin degradation was not significantly different in the tetracycline-treated rats from the normal rats. The present data suggests that insulin resistance and hyperinsulinemia underlie the observed metabolic disturbances that characterize fatty liver disease.

Natal dispersal and genetic structure in a population of the European wild rabbit (Oryctolagus cuniculus)

A combination of behavioural observation, DNA fingerprinting, and allozyme analysis were used to examine natal dispersal in a wild rabbit population. Rabbits lived in territorial, warren based social groups. Over a 6-year period, significantly more male than female rabbits moved to a new social group before the start of their first breeding season. This pattern of female philopatry and male dispersal was reflected in the genetic structure of the population. DNA fingerprint band-sharing coefficients were significantly higher for females within the same group than for females between groups, while this was not the case for males. Wright's inbreeding coefficients were calculated from fingerprint band-sharing values and compared to those obtained from allozyme data. There was little correlation between the relative magnitudes of the F-statistics calculated using the two techniques for comparisons between different social groups. In contrast, two alternative methods for calculating FST from DNA fingerprints gave reasonably concordant values although those based on band-sharing were consistently lower than those calculated by an 'allele' frequency approach. A negative FIS value was obtained from allozyme data. Such excess heterozygosity within social groups is expected even under random mating given the social structure and sex-biased dispersal but it is argued that the possibility of behavioural avoidance of inbreeding should not be discounted in this species. Estimates of genetic differentiation obtained from allozyme and DNA fingerprint data agreed closely with reported estimates for the yellow-bellied marmot, a species with a very similar social structure to the European rabbit.

Acquired protein S deficiency in a patient with systemic lupus erythematosus causing central retinal vein thrombosis

A 16 year old girl with systemic lupus erythematosus (SLE) developed the rare complication of central retinal vein occlusion. Although classically a disease of older patients, it has been recognised in association with SLE but only in the presence of the lupus anticoagulant or antiphospholipid antibodies. The thrombosis occurred when free protein S concentrations were transiently reduced and there was no family history or other known causes of reduced protein S concentrations. No other prothrombotic risk factors were present.

Lupus anticoagulant in the elderly may be associated with both quinine and quinidine usage

Thirty-one patients aged over 60 yrs and with lupus anticoagulant (LA) were reviewed for their drug intake. Twenty-three (73%) were taking cinchona alkaloids, 10 (32%) quinine for night cramps, 11 (35%) quinidine for cardiac arrhythmia and 2 (6%) were taking both. These frequencies of drugs usage differed significantly from age and sex matched controls (p < 0.001). Five patients had features suggestive of the antiphospholipid syndrome. Repeat testing showed persistent LA activity in all but 2 of 5 patients in whom the relevant drug had been ceased. This is the first description of a possible causal association between LA and quinine therapy.

Postglacial expansion and genome subdivision in the European grasshopper Chorthippus parallelus

A noncoding nuclear DNA marker sequence (Cpn1-1) was used to investigate subdivision in the grasshopper Chorthippus parallelus and deduce postglacial expansion patterns across its species range in Europe. Investigation of the spatial distribution of 71 Cpn1-1 haplotypes and estimation of levels of genetic differentiation (KST values) between populations and geographic regions provided evidence for subdivision of C. parallelus into at least five major geographic regions and indicated that the French form of C. parallelus originated after range expansion from a Balkan refugium. Further evidence for subdivision of C. parallelus between Italy and northern Europe suggests that the Alps may have formed a significant barrier to gene flow in this grasshopper.

Mild bleeding disorders. A clinical and laboratory study

OBJECTIVE

To investigate in-vitro haemostasis in subjects with symptoms suggesting a mild bleeding disorder.

DESIGN

A prospective study in which an extensive range of in-vitro tests were applied unselectively.

SETTING

Patients were referred from community-based practices and hospital outpatient services.

PATIENTS

Ninety-three consecutive patients were examined. Hospital patients with severe illness were excluded.

CLINICAL FEATURES

Patients presented with easy bruising (68%), epistaxis (12%), excessive operative bleeding (7%), menorrhagia (4%), haematuria (3%), dental bleeding (1%) and bleeding from other sites (5%). In no instance was the bleeding life threatening.

OUTCOME MEASURES

Results of laboratory tests for patients presenting with the symptoms of a mild bleeding disorder were compared with the results for a healthy reference group.

RESULTS

Abnormal results of in-vitro tests were found in 53% of the subjects. Thirteen per cent had a prolonged bleeding time, of whom the majority had abnormal results of other in-vitro tests. Von Willebrand's disease was diagnosed in 7% of patients, although only half of these had a prolonged bleeding time.

CONCLUSIONS

Abnormal results of in-vitro tests were prevalent among subjects with symptoms of mild bleeding disorder. Easy bruising was as powerful a clue as any other bleeding manifestation to the presence of an abnormal in-vitro test result.

Automation of the Kaolin Clotting Time

An automated Kaolin Clotting Time (KCT) has been developed to simplify screening for the Lupus Anticoagulant (LA). The assay is performed on the ACL300 Research coagulation analyser, but may be modified for other centrifugal analysers. Automation of the KCT allows up to 17 delta KCT (delta KCT) screens (Gibson J, Starling E, Date L et al. Simplified screening procedure for detecting lupus inhibitor. J Clin Pathol 1988; 44: 226-31) or 2 full Exner curves (Exner T, Rickard KA, Kronenberg H. A sensitive test demonstrating lupus anticoagulant and its behavioural patterns. Br J Haematol 1978; 40: 143-51) to be performed in one test cycle. An automated and manual delta KCT screen was performed on 17 patients with a previously diagnosed LA, 41 hospital patients having routine coagulation studies and 37 blood donors. In addition, 11 patients on full-dose heparin and 12 patients with stable warfarin anticoagulation were tested. The correlation between the automated delta KCT and the manual delta KCT was 0.958 (p less than 0.001). A full Exner curve was performed on 5 of the patients with a LA and 1 blood donor which demonstrated that the automated KCT produced results entirely comparable with the manual method. The automated KCT is a quick, inexpensive approach to screening patients for the presence of LA.

The effect of vitamin B12 on tetracycline-induced fatty liver

The effect of vitamin B12 on the metabolic alterations due to tetracycline toxicity was studied experimentally on laboratory animals. Treatment of Sprague-Dawley rats with 120 or 250 mg tetracycline (i.p.) per kg per day for two or three days caused an accumulation of lipids, mainly triglycerides in the liver of 75% of animals studied, while phospholipid level tend to decrease. These doses are approximately twice and four times the recommended maximum dose for man. In the present work no direct relationship was observed between dose of tetracycline and hepatic accumulation of triglyceride, although livers of rats treated with 250 mg tetracycline/kg appeared uniformly pale yellow. Elevated serum triglyceride was found predominantly in rats treated with 120 mg/kg, while there was no obvious difference between serum triglyceride of rats treated with 250 mg tetracycline and control rats, indicating a block in the release of hepatic triglycerides. Where protection by vitamin B12 was studied, the vitamin was given i.m. (50 microgram/animal) 3 hours before the injection of 120 mg tetracycline per kg. There was a good evidence that lipid abnormalities caused by tetracycline improved by vitamin B12. Thus both hepatic and serum total lipid and triglycerides were significantly lower than those of rats treated with tetracycline, although hepatic total cholesterol was significantly increased as in case of tetracycline only.

Evaluation of the effect of lead exposure on the liver in Egyptian lead tank welders

In a group of Egyptian lead tank welders who were exposed to lead fumes for periods to 22 years the changes in serum lipids and some of the liver function tests which may elucidate the effect of lead on the liver were investigated. The results revealed increased blood lead level associated with decreased blood haemoglobin and increased urinary excretion of delta amino levulinic acid. However, no clinical abnormalities were recorded in the exposed group of the present work. Thus the increase in serum triglycerides and B-lipoprotein together with the lowering of the phospholipid/cholesterol ratio which were found may indicate premature development of atherosclerosis. Indirect evidence of the beginning of liver fattening was also provided by the increase in serum GOT, GPT, LDH enzymes and decreased albumin/globulin ratio besides the changes in serum lipid values. It is concluded therefore that lead poisoning may have a vascular as well as hepato-toxic action.