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Biomedical subjects

M Potts

Publications and source records attributed to M Potts.

At least 19 recordsLinked to original sources
PubMed2006

Misoprostol and active management of the third stage of labor.

OBJECTIVE: To compare current practices for the active management of the third stage of labor (AMTSL) with the use of 600 mug of oral misoprostol. METHODS: An operations research study was designed to compare blood loss with current AMTSL practices and misoprostol use. RESULTS: Women in the misoprostol group were less likely to bleed 500 ml or more (adjusted odds ratio, 0.30; 95% confidence interval, 0.16-0.56) compared with those in the current practices group. In the current practices group 73% women required interventions because of postpartum hemorrhage, compared with 11% in the misoprostol group. CONCLUSION: In situations where oxytocin and or ergometrine are not consistently and appropriately used during third stage of labor, misoprostol should be considered for inclusion in the AMTSL protocol.

Administration, Oral↗
PubMed2006

Autism and diet.

Explore the source record for details and available documents.

Autistic Disorder↗
PubMed2005

Controlling postpartum hemorrhage after home births in Tanzania.

OBJECTIVES: Determine safety of household management of postpartum hemorrhage (PPH) with 1000 microg of rectal misoprostol, and assess possible reduction in referrals and the need for additional interventions. METHODS: Traditional birth attendants (TBAs) in Kigoma, Tanzania were trained to recognize PPH (500 ml of blood loss). Blood loss measurement was standardized by using a local garment, the "kanga". TBAs in the intervention area gave 1000 microg of misoprostol rectally when PPH occurred. Those in the non-intervention area referred the women to the nearest facility. RESULTS: 454 women in the intervention and 395 in the non-intervention areas were eligible. 111 in the intervention area and 73 in the non-intervention had PPH. Fewer than 2% of the PPH women in the intervention area were referred, compared with 19% in the non-intervention. CONCLUSION: Misoprostol is a low cost, easy to use technology that can control PPH even without a medically trained attendant.

Administration, Rectal↗
PubMed2005

Does it matter that organ donors are not dead? Ethical and policy implications.

The "standard position" on organ donation is that the donor must be dead in order for vital organs to be removed, a position with which we agree. Recently, Robert Truog and Walter Robinson have argued that (1) brain death is not death, and (2) even though "brain dead" patients are not dead, it is morally acceptable to remove vital organs from those patients. We accept and defend their claim that brain death is not death, and we argue against both the US "whole brain" criterion and the UK "brain stem" criterion. Then we answer their arguments in favour of removing vital organs from "brain dead" and other classes of comatose patients. We dispute their claim that the removal of vital organs is morally equivalent to "letting nature take its course", arguing that, unlike "allowing to die", it is the removal of vital organs that kills the patient, not his or her disease or injury. Then, we argue that removing vital organs from living patients is immoral and contrary to the nature of medical practice. Finally, we offer practical suggestions for changing public policy on organ transplantation.

Brain Death↗
PubMed2001

Expression of intercellular adhesion molecule-1 in the cortex of preserved rat kidneys.

BACKGROUND: Prolonged cold ischemia has been shown to be an important factor in the development of posttransplant renal dysfunction. The exact mechanisms have not been completely defined. The expression of intercellular adhesion molecule-1 (ICAM-1) (CD 54) in rat kidneys stored in University of Wisconsin (UW) solution was studied in an attempt to correlate ischemia time with immunogenicity of the graft. METHODS: Kidneys from male Lewis rats were perfused with UW solution, removed, and bathed in UW solution at 4 degrees C for 4, 12, 24, and 48 h. For the evaluation of expression of ICAM-1, immunohistochemical staining, Western blotting, and semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) were performed. RESULTS: Immunohistochemical staining in normal, nonischemic kidneys revealed that glomerular capillaries expressed ICAM-1 but that tubular cells did not. The preserved kidneys were analyzed by immunohistochemistry, Western blotting, and semiquantitative RT-PCR and showed increased transcription and expression of ICAM-1 in the cortex of the kidney. Expression reached a maximum at 24 h and declined at 48 h. The ICAM-1 protein expression in the preserved kidney cortex relative to control kidneys was increased at 4 h (1.68 +/- 0.60-fold of control kidneys, P = 0.06), 12 h (2.38 +/- 0.90-fold, P = 0.02), 24 h (3.70 +/- 1.29-fold, P = 0.01), and 48 h (2.00 +/- 0.54-fold, P = 0.01). The messenger RNA expression (the ratio of ICAM-1 to glyceraldehyde-3-phosphate dehydrogenase) in preserved kidneys cortex relative to control kidneys was increased at 4 h (1.19 +/- 0.14-fold of control kidneys), 12 h (1.38 +/- 0.16-fold), 24 h (1.77 +/- 0.29-fold), and 48 h (1.19 +/- 0.12-fold) (P < 0.05 for all time points). CONCLUSIONS: We conclude that cold preservation of rat kidneys in UW solution induces increasing levels of ICAM-1 cell surface expression and gene transcription. Further study is necessary to determine if this increase in adhesion molecule expression increases the immunogenicity of the allograft and contributes to the development of posttransplant renal dysfunction.

Adenosine↗
PubMed2001

Engineering mammalian cells for solid-state sensor applications.

A fundamental advance in the development and application of cell- and tissue-based biosensors would be the ability to achieve air-dry stabilization of mammalian (especially human) cells with subsequent recovery following rehydration. The would allow for the preparation of sensors with extended shelf lives, only requiring the addition of water for activation. By understanding and subsequently employing the tactics used by desiccation-tolerant extremophiles, it may be possible to design stabilized mammalian cell-based biosensors. The approaches required to realize this goal are discussed and illustrated with several examples.

Bacterial Proteins↗
PubMed2001

Desiccation tolerance: a simple process?

Water is essential for life, and thus the removal of water from a cell is a severe, often lethal stress. This is not a remarkable observation but it is one that is often taken for granted. Desiccation-tolerant cells implement structural, physiological and molecular mechanisms to survive severe water deficit. These mechanisms, and the components and pathways which facilitate them, are poorly understood. Here, recent developments are considered to illustrate the importance of desiccation, longevity and cell stasis in basic microbiology, and the relevance of the topic to the metabolic engineering of sensitive cells, including those of humans.

Adaptation, Physiological↗
PubMed2001

Locating, characterizing and minimizing sources of error for a paper case-based structured oral examination in a multi-campus clerkship.

OBJECTIVE: To determine consistency of assessment in a new paper case-based structured oral examination in a multi-community pediatrics clerkship, and to identify correctable problems in the administration of examination and assessment process. METHOD: Nine paper case-based oral examinations were audio-taped. From audio-tapes five community coordinators scored examiner behaviors and graded student performance. Correlations among examiner behaviors scores were examined. Graphs identified grading patterns of evaluators. The effect of exam-giving on evaluators was assessed by t-test. Reliability of grades was calculated and the effect of reducing assessment problems was modeled. RESULTS: Exam-givers differed most in their "teaching-guiding" behavior, and this negatively correlated with student grades. Exam reliability was lowered mainly by evaluator differences in leniency and grading pattern; less important was absence of standardization in cases. CONCLUSIONS: While grade reliability was low in early use of the paper case-based oral examination, modeling of plausible effects of training and monitoring for greater uniformity in administration of the examination and assigning scores suggests that more adequate reliabilities can be attained.

Clinical Clerkship↗
PubMed2001

An overview of the genome of Nostoc punctiforme, a multicellular, symbiotic cyanobacterium.

Nostoc punctiforme is a filamentous cyanobacterium with extensive phenotypic characteristics and a relatively large genome, approaching 10 Mb. The phenotypic characteristics include a photoautotrophic, diazotrophic mode of growth, but N. punctiforme is also facultatively heterotrophic; its vegetative cells have multiple developmental alternatives, including terminal differentiation into nitrogen-fixing heterocysts and transient differentiation into spore-like akinetes or motile filaments called hormogonia; and N. punctiforme has broad symbiotic competence with fungi and terrestrial plants, including bryophytes, gymnosperms and an angiosperm. The shotgun-sequencing phase of the N. punctiforme strain ATCC 29133 genome has been completed by the Joint Genome Institute. Annotation of an 8.9 Mb database yielded 7432 open reading frames, 45% of which encode proteins with known or probable known function and 29% of which are unique to N. punctiforme. Comparative analysis of the sequence indicates a genome that is highly plastic and in a state of flux, with numerous insertion sequences and multilocus repeats, as well as genes encoding transposases and DNA modification enzymes. The sequence also reveals the presence of genes encoding putative proteins that collectively define almost all characteristics of cyanobacteria as a group. N. punctiforme has an extensive potential to sense and respond to environmental signals as reflected by the presence of more than 400 genes encoding sensor protein kinases, response regulators and other transcriptional factors. The signal transduction systems and any of the large number of unique genes may play essential roles in the cell differentiation and symbiotic interaction properties of N. punctiforme.

Journal Article↗
PubMed2001

Meeting the contraceptive and AIDS prevention needs of people living on a dollar a day.

The new millennium sees the largest cohort of young people in history entering its fertile years. Many of these people are too poor to pay the full cost of modern contraception, but the money available for subsidizing their needs is exceedingly limited. The AIDS pandemic is placing additional, unprecedented demand on already overstretched resources. Existing methods of contraception that are well established and off-patent can be produced in bulk at low cost, and will remain the backbone of future programmes. The use of misoprostol as an abortifacient is likely to spread rapidly. New methods must take into account the limitations of the health infrastructure in developing countries and the imperative of low cost. Given the constraints of money, skills and facilities, it is essential to set realistic priorities for future contraceptive research and development. It is suggested that the greatest needs are for a woman-controlled method of preventing HIV transmission and for a non-surgical method of female sterilization.

Abortion, Induced↗
PubMed2001

A requiem for whole brain death: a response to D. Alan Shewmon's 'the brain and somatic integration'.

Alan Shewmon's article, 'The brain and somatic integration: Insights into the standard biological rationale for equating "brain death" with death' (2001), strikes at the heart of the standard justification for whole brain death criteria. The standard justification, which I call the 'standard paradigm', holds that the permanent loss of the functions of the entire brain marks the end of the integrative unity of the body. In my response to Shewmon's article, I first offer a brief summary of the standard paradigm and cite recent work by advocates of whole brain criteria who tenaciously cling to the standard paradigm despite increasing evidence showing that it has significant weaknesses. Second, I address Shewmon's case against the standard paradigm, arguing that he is successful in showing that whole brain dead patients have integrated organic unity. Finally, I discuss some minor problems with Shewmon's article, along with suggestions for further elaboration.

Bioethics↗
PubMed2001

Form species Nostoc commune (Cyanobacteria).

The form species concept for the Cyanobacteria was evaluated using a comprehensive set of Nostoc samples that were collected during the past two centuries, from all continents, including regions from the Tropics to the Poles. Phylogenies were constructed based upon the conserved regions of tRNALeu (UAA) group I intron DNA sequences. Thirty-four forms contained a tRNALeu (UAA) intron of 284 nt. These 284-nt introns contained 200 nt of conserved sequence that, in most cases, shared 100% sequence identity, they had three variable regions (I, II and III) amounting to 84 nt, contained no hypervariable region and formed a discrete cluster in phylogenetic analysis. These forms represented 31 independent populations in both hemispheres and constitute examples of form species Nostoc commune. Multiple introns were obtained from several of the populations. Ten populations contained introns of 287-340 nt with a hypervariable region, 8 to 59 nt in length, located between variable regions I and II. Alignments identified 15 examples where 5'-AAAAUCC-3' occurred at the hypervariable region-variable region II boundary; this sequence is identical to the conserved sequence at the 3' intron-exon boundary (splice site) within the tRNALeu (UAA) gene. The possibility that hypervariable regions were removed from the primary intron through secondary splicing was tested in vitro but proved to be negative under the experimental conditions used. Shared morphologies of genetically different strains, dissimilar morphologies in strains that share identical genetic markers, incorrect naming of culture collection strains and genetic drift in cultured strains emphasize that the successful delineation of cyanobacterial species requires the application of multiple taxonomic criteria.

Base Sequence↗
PubMed2001

Gene transfer to the desiccation-tolerant cyanobacterium Chroococcidiopsis.

The coccoid cyanobacterium Chroococcidiopsis dominates microbial communities in the most extreme arid hot and cold deserts. These communities withstand constraints that result from multiple cycles of drying and wetting and/or prolonged desiccation, through mechanisms which remain poorly understood. Here we describe the first system for genetic manipulation of Chroococcidiopsis. Plasmids pDUCA7 and pRL489, based on the pDU1 replicon of Nostoc sp. strain PCC 7524, were transferred to different isolates of Chroococcidiopsis via conjugation and electroporation. This report provides the first evidence that pDU1 replicons can be maintained in cyanobacteria other than Nostoc and Anabaena. Following conjugation, both plasmids replicated in Chroococcidiopsis sp. strains 029, 057, and 123 but not in strains 171 and 584. Both plasmids were electroporated into strains 029 and 123 but not into strains 057, 171, and 584. Expression of P(psbA)-luxAB on pRL489 was visualized through in vivo luminescence. Efficiencies of conjugative transfer for pDUCA7 and pRL489 into Chroococcidiopsis sp. strain 029 were approximately 10(-2) and 10(-4) transconjugants per recipient cell, respectively. Conjugative transfer occurred with a lower efficiency into strains 057 and 123. Electrotransformation efficiencies of about 10(-4) electrotransformants per recipient cell were achieved with strains 029 and 123, using either pDUCA7 or pRL489. Extracellular deoxyribonucleases were associated with each of the five strains. Phylogenetic analysis, based upon the V6 to V8 variable regions of 16S rRNA, suggests that desert strains 057, 123, 171, and 029 are distinct from the type species strain Chroococcidiopsis thermalis PCC 7203. The high efficiency of conjugative transfer of Chroococcidiopsis sp. strain 029, from the Negev Desert, Israel, makes this a suitable experimental strain for genetic studies on desiccation tolerance.

Base Sequence↗