Local anesthetic activity of mixtures of cis- and trans-(2-dimethylaminomethylcycloheptyl)-2-alkoxyphenylcarbamates.

In a previous study, we synthesized two homologous series of racemic stereoisomeric cis- and trans-(2-dimethylaminomethylcycloheptyl)-2-alkoxyphenylcarbamates with alkyl chain lengths ranging from C1 to C8 and analyzed their local anesthetic activity. Here, we show that the local anesthetic activities of mixtures of cis-1 and trans-1 stereoisomers are higher than the sum of activities calculated for the individual stereoisomers at all molar fractions. We conclude that an appropriate ratio of cis- and trans-stereoisomers is necessary to achieve the maximum anesthetic activity of the studied stereoisomeric carbamates.

Mitochondrial Mg(2+) homeostasis is critical for group II intron splicing in vivo.

The product of the nuclear MRS2 gene, Mrs2p, is the only candidate splicing factor essential for all group II introns in mitochondria of the yeast Saccharomyces cerevisiae. It has been shown to be an integral protein of the inner mitochondrial membrane, structurally and functionally related to the bacterial CorA Mg(2+) transporter. Here we show that mutant alleles of the MRS2 gene as well as overexpression of this gene both increase intramitochondrial Mg(2+) concentrations and compensate for splicing defects of group II introns in mit(-) mutants M1301 and B-loop. Yet, covariation of Mg(2+) concentrations and splicing is similarly seen when some other genes affecting mitochondrial Mg(2+) concentrations are overexpressed in an mrs2Delta mutant, indicating that not the Mrs2 protein per se but certain Mg(2+) concentrations are essential for group II intron splicing. This critical role of Mg(2+) concentrations for splicing is further documented by our observation that pre-mRNAs, accumulated in mitochondria isolated from mutants, efficiently undergo splicing in organello when these mitochondria are incubated in the presence of 10 mM external Mg(2+) (mit(-) M1301) and an ionophore (mrs2Delta). This finding of an exceptional sensitivity of group II intron splicing toward Mg(2+) concentrations in vivo is unprecedented and raises the question of the role of Mg(2+) in other RNA-catalyzed reactions in vivo. It explains finally why protein factors modulating Mg(2+) homeostasis had been identified in genetic screens for bona fide RNA splicing factors.

The human mitochondrial Mrs2 protein functionally substitutes for its yeast homologue, a candidate magnesium transporter.

We report here on the human MRS2 gene that encodes a protein, hsaMrs2p, the first molecularly characterized candidate for a magnesium transporter in metazoa. The protein, like the yeast mitochondrial Mrs2 and Lpe10 proteins, contains two predicted transmembrane domains in its carboxyl-terminus, the first of which terminates with the conserved motif F/Y-G-M-N. These are typical features of the CorA family of magnesium transporters. Expression of hsaMrs2p in mrs2-1 knock-out mutant yeast partly restores mitochondrial magnesium concentrations that are significantly reduced in this mutant. It also alleviates other defects of this mutant, which may be secondary to the reduction in magnesium concentrations. These findings suggest that hsaMrs2p and yMrs2p are functional homologues. Like its yeast homologues, hsaMrs2p has been localized in mitochondria. The hsaMRS2 gene is located on chromosome 6 (6p22.1-p22.3) and is composed of 11 exons. A low level of the transcript is detected in various mouse tissues.

Characterization of a novel human putative mitochondrial transporter homologous to the yeast mitochondrial RNA splicing proteins 3 and 4.

We report here a novel human gene, hMRS3/4, encoding a putative mitochondrial transporter structurally and functionally homologous to the yeast mitochondrial RNA splicing proteins 3 and 4. These proteins belong to the family of mitochondrial carrier proteins (MCF) and are likely to function as solute carriers. hMRS3/4 spans approximately 10 kb of genomic DNA on chromosome 10q24 and consists of four exons that encode a 364-aa protein with six transmembrane domains. A putative splice variant, encoding a 177-aa protein with three transmembrane domains, was also identified. hMRS3/4 has a well-conserved signature sequence of MCF and is targeted into the mitochondria. When expressed in yeast, hMRS3/4 efficiently restores the mitochondrial functions in mrs3(o)mrs4(o) knock-out mutants. Ubiquitous expression in human tissues and a well-conserved structure and function suggest an important role for hMRS3/4 in human cells.

The mitochondrial inner membrane protein Lpe10p, a homologue of Mrs2p, is essential for magnesium homeostasis and group II intron splicing in yeast.

The yeast ORF YPL060w/LPE10 encodes a homologue of the mitochondrial protein Mrs2p. These two proteins are 32% identical, and have two transmembrane domains in their C-terminal regions and a putative magnesium transporter signature, Y/F-G-M-N, at the end of one of these domains. Data presented here indicate that Lpe10p is inserted into the inner mitochondrial membrane with both termini oriented towards the matrix space. Disruption of the LPE10 gene results in a growth defect on non-fermentable substrates (petite phenotype) and a marked defect in group II intron splicing. The fact that in intron-less strains lpe10 disruptants also exhibit a petite phenotype indicates that functions other than RNA splicing are affected by the absence of Lpe10p. In the mitochondria, concentrations of magnesium, but not of several other divalent metal ions, are increased when Lpe10p is overexpressed and reduced when it is absent. Magnesium concentrations are raised to normal levels and growth on non-fermentable substrates is partially restored by the expression of CorA, the bacterial magnesium transporter, in the lpe10 disruptant. These features are similar to those previously reported for Mrs2p, suggesting that Lpe10p and Mrs2p are functional homologues. However, they cannot easily substitute for each other. Their roles in magnesium homeostasis and, possibly as a secondary effect, in RNA splicing are discussed.

A member of a novel Arabidopsis thaliana gene family of candidate Mg2+ ion transporters complements a yeast mitochondrial group II intron-splicing mutant.

Autocatalytic activity of some group II introns has been demonstrated in vitro, but helper functions such as the yeast MRS2 protein are essential for splicing in vivo. In our search for such helper factors in plants, we pursued the cloning of two Arabidopsis thaliana homologues, atmrs2-1 and atmrs2-2. Atmrs2-1, but not atmrs2-2, complements the yeast deletion mutant of mrs2, and this is congruent with the prediction of two adjacent transmembrane stretches in AtMRS2-1 and yeast MRS2 but not in AtMRS2-2. This complementation depends on fusion of the native yeast mitochondrial import sequence to atmrs2-1. A differing, non-mitochondrial, cellular targeting in Arabidopsis is supported by the analysis of green fluorescent protein fusion constructs after transient transformation into plant protoplasts. Further members of what now appears to be a family of 10 mrs2 homologues are identified in the Arabidopsis genome. Similarity searches with the PSI-BLAST algorithm in the protein database fail to identify homologues of this novel gene family in any eukaryotes other than yeasts, but do identify its distant relatedness to the corA group of bacterial magnesium transporters. In line with this observation, intramitochondrial magnesium concentrations are indeed restored to wild-type levels in the yeast mutant on complementation with atmrs2-1.

Needs assessment in primary care: general practitioners' perceptions and implications for the future.

BACKGROUND: Health needs assessment can guide the appropriate shift to primary care by identifying the most effective and efficient resource allocation to meet the needs of populations. Assessing health care needs will be a continuing challenge for primary care trusts in Scotland (or equivalent groups in other parts of the United Kingdom); however, lessons must be learned from the experience of needs assessment that followed the 'internal market' reforms of the 1990s. AIM: To examine general practitioners' (GPs') awareness and experience of needs assessment, to identify barriers to needs assessment in primary care, and to ascertain how better progress might be made in the future. METHOD: A postal questionnaire survey of 1777 Scottish GPs (a one-in-two sample) was combined with a semistructured interview survey of 'lead' GPs from a random sample of 64 mainland Scottish practices between May and August 1996. RESULTS: Sixty-five per cent (1154) of GPs responded to the questionnaire, of which 54% (965) were completed. Over 73% (47) of interviews were completed. Most GPs were unfamiliar with the concept of needs assessment and there was no evidence that needs assessment had influenced commissioning decisions. Most GPs argued that it was not a 'core' activity and that they lacked training in the relevant skills. While the attitude of the majority was indifferent, cynical, and sometimes hostile, a minority, comprising mostly younger fundholders, was more enthusiastic about needs assessment. CONCLUSION: The motivation and attitude of the majority of GPs present a barrier to needs assessment in primary care. GPs will require more resources and training if they are to undertake this responsibility. Most GPs believe than incentives (financial or organisational) will be necessary. Primary care trusts and equivalent structures should be aware of these attitudes as they seek to establish plans based on estimates of population needs in defined locations.

The bacterial magnesium transporter CorA can functionally substitute for its putative homologue Mrs2p in the yeast inner mitochondrial membrane.

The yeast nuclear gene MRS2 encodes a protein of 54 kDa, the presence of which has been shown to be essential for the splicing of group II intron RNA in mitochondria and, independently, for the maintenance of a functional respiratory system. Here we show that the MRS2 gene product (Mrs2p) is an integral protein of the inner mitochondrial membrane. It appears to be inserted into this membrane by virtue of two neighboring membrane spanning domains in its carboxyl-terminal half. A large amino-terminal and a shorter carboxyl-terminal part are likely to be exposed to the matrix space. Structural features and a short sequence motif indicate that Mrs2p may be related to the bacterial CorA Mg2+ transporter. In fact, overexpression of the CorA gene in yeast partially suppresses the pet- phenotype of an mrs2 disrupted yeast strain. Disruption of the MRS2 gene leads to a significant decrease in total magnesium content of mitochondria which is compensated for by the overexpression of the CorA gene. Mutants lacking or overproducing Mrs2p exhibit phenotypes consistent with the involvement of Mrs2p in mitochondrial Mg2+ homeostasis.

Associations between road traffic accidents and socio-economic deprivation on Scotland's west coast.

Road traffic accidents (RTAs) are declining, but remain a public health concern locally and world-wide. Scottish RTAs killed 316 people and injured over 20,000 in 1996. By 2020, they are predicted to become the world's third-leading cause of sickness and death. Little is know about associations between RTAs and deprivation; it has never been explored on Scotland's West Coast. This study analysed hospital A&E admissions and investigated associations between RTAs and socio-economic status. 1,300 attendance records at a 575-bed NHS Trust Accident & Emergency in North Lanarkshire were reviewed and 1,020 records analysed in conjunction with Health Board socio-economic data. Findings strongly suggest (p = 0.00461) a positive trend between RTA activity and deprivation. Significance held for gender, victim role, purpose of journey and age, except for drivers 60 and over. Given the preventative nature of RTAs and their contribution to morbidity and mortality, further research between RTAs and deprivation is suggested.

A study to determine how needs assessment is being used to improve health.

OBJECTIVE: To determine how needs assessment is being used in Health Authorities and General Practice. DESIGN: A postal survey of a one in two sample of Scottish GPs, semistructured interviews with selected health authority executives and a random sample of GPs. SUBJECTS: Nine hundred and sixty-five GPs (54% of those sent the postal questionnaire), 47 randomly selected GP practices and 36 selected health authority (called health boards in Scotland) executives. RESULTS: In health authorities, a view of commissioning/planning emerged with three components: (1) planning (including needs assessment); (2) leadership; and (3) strong relationships with stakeholders. Health authority executives believed that GP involvement is one of several vital components but doubted the commitment of all but a few GPs to the planning process. GPs welcomed enhanced influence but feared increases in workload and admitted to a lack of training in the skills required for needs assessment. Health authority executives aspired to place needs assessment at the centre of planning but admitted that, at present, cost and volume issues predominate. Most GPs were not involved in needs assessment and argued that it is not part of a GPs core activity. National needs assessment documents were well received by health authorities but made little or no impact on GPs. CONCLUSIONS: Needs assessment will have little involvement from primary care until there are changes in the attitudes and skills of the majority of GPs. Fundamental changes are required in health authority priorities and practice if their rhetoric about needs assessment is to be turned into reality. The role of needs assessment could be enhanced but this will only happen if it can be shown to lead to improved health outcomes while addressing the financial pressures that currently dominate the agenda.

Stereoisomeric effect on antimicrobial activity of a series of quaternary ammonium salts.

Two homologous series of diastereoisomeric racemic +/- cis and +/- trans-N,N-dimethyl-N-alkyl-2-benzoyloxycyclohexylmethylammonium bromides with the number of carbon atoms in the alkyl chain from six to twenty (m = 6,8 ... 20) were synthesised. Their structures have been elucidated by IR, UV and in some cases also with 1H and 13C NMR spectrometry. The title compounds were assayed for their antimicrobial activity on microorganisms S. aureus, E. coli and C. albicans. The highest antimicrobial activity was observed against S. aureus (log 1/MIC = 5.5 mol-1 dm3) and the lowest against E. coli (log 1/MIC = 4.5 mol-1 dm3). The +/- cis and +/- trans stereoisomers of all eight couples of diastereoisomeric compounds show differences in their physico-chemical characteristics (including partition coefficient and lipophilicity) which is also reflected in the different antimicrobial activity of these diastereoisomers.