Euthanasia. Predictions of outcomes can be wrong.
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Ethics, Medical↗
Biomedical subjects
J Gilbert
Publications and source records attributed to J Gilbert.
Measles immunization of 2-year-olds in a rural southern state.
OBJECTIVE: To assess the measles vaccine coverage of 2-year-old children living in Mississippi during the national measles epidemic of 1989 and 1990. DESIGN: Survey of 2-year-olds randomly selected from the 1987 birth cohort. The status of measles-mumps-rubella (MMR) vaccination was determined by medical record reviews and family contacts. SETTING: A predominantly rural state in the southeastern United States with a large black minority population (35%) and a low per capital income ($9827 to $12,899). Approximately 80% of MMR immunizations are given by public health service nurses working in nine health districts. SUBJECTS: A total of 2450 preschool-aged children representing 6% of the 1987 birth cohort (n = 41,279). Three hundred forty-one children were considered ineligible, leaving 2109 in the final sample. MAIN OUTCOME MEASURES: Confirmed vaccination by the age of 2 years. Rates of immunization were calculated for the entire state, its health districts, and subgroups based on population density, per capita income, type of clinic visited, and race. RESULTS: The statewide immunization rate was 87% (95% confidence interval, 86% to 88%). Among the nine health districts, rates varied from 79% to 97% (median, 88%). They were similar for white and black children in each health district and within the state as a whole. The level of vaccine coverage was significantly higher in districts with lower population densities (89% vs 85%, P = .02) and in those with higher per capita incomes (89% vs 86%, P = .03). There were four minor outbreaks of measles during 1989 and 1990; half of the cases occurred in unimmunized children too young to receive the MMR vaccine. CONCLUSION: A high rate of measles immunization is attainable among 2-year-olds living in a rural state with a large black minority population and limited economic resources.
Child, Preschool↗
The fate of environmental contaminants in the food chain.
This paper reviews the major sources of industrial environmental pollutants that may give rise to organic contaminants in foods, indicates which foods tend to be most frequently found to be contaminated and summarises available data on levels of occurrence. Polycyclic aromatic hydrocarbons (PAHs), phthalic acid esters, polychlorinated dibenzodioxins and dibenzofurans (PCDDs and PCDFs), polychlorinated biphenyls (PCBs) and organic phosphates are widespread environmental contaminants which have all been detected in foods. Estimates of exposure to these contaminants from total diet and other studies are summarised. Some pollutants such as volatile halocarbons and benzene tend to only occur as localised contaminants for which targeted monitoring of foods is necessary. The most difficult area is regarded as the detection of previously unrecognised contaminants in foods for which some possible approaches are described.
Environmental Pollutants↗
Noradrenaline, dopamine and serotonin levels and metabolism in the human hypothalamus: observations in Parkinson's disease and normal subjects.
In order to determine whether, besides the severe striatal dopamine (DA) loss, other brain neurotransmitter changes may be a constant biochemical feature of idiopathic Parkinson's disease (iPD), we measured the concentration of the three major brain monoamines noradrenaline (NA), DA, and serotonin (5-HT) and their metabolites in five rostro-caudal subdivisions of the hypothalamus of eight control patients and nine patients with morphologically confirmed iPD. In the whole hypothalamus of the iPD patients we found a mild to moderate mean reduction of NA (-52%, P < 0.05), DA (-25%), and 5-HT (-26%). At the subregional level, the most consistently affected area was the intermediate subdivision of the hypothalamus proper where all three monoamines were statistically significantly reduced. Evaluation of individual patient values indicated that, in contrast to the constant and severe DA reduction present in putamen of each of the iPD patients (DA loss ranging from 96% to 99%), several of these patients had whole (and subregional) hypothalamic monoamine values well within the range of controls. We conclude that, although possibly involved in autonomic and/or endocrine disturbances in some patients with iPD, none of the observed monoamine changes in the hypothalamus is an obligatory feature of iPD. Our study demonstrates the need for evaluation of individual patient values rather than mean differences in order to permit valid conclusions to be drawn as to whether an observed neurochemical change can be regarded as specific to a given brain disorder.
Aged↗
Investigation of stiffness and microstructure of joints soldered with gas-oxygen torch and infrared methods.
The stiffness of soldered connectors fabricated with the gas-oxygen torch technique was compared with those fabricated with the infrared technique. Untreated solder materials were used as controls. Untreated solder materials of gold-palladium, palladium-silver, and chromium-cobalt alloys exhibited significantly higher stiffness than the soldered specimens fabricated with either method. There was no significant difference between the gas-oxygen torch and the infrared groups of the gold-palladium and palladium-silver alloys. Photomicrographs revealed that the soldered specimens displayed porosities. For the chromium-cobalt alloy, the infrared group demonstrated significantly higher stiffness than the gas-oxygen torch group. Photomicrographs also disclosed that the chromium-cobalt alloy soldered with the gas-oxygen torch technique had a significant heat-affected zone.
Analysis of Variance↗
A comparison of the hardness of different types of titanium and conventional metal ceramics.
This study compared the surface hardness of machine milled titanium and cast titanium, and the surface hardness profile of a gold-palladium alloy, a nickel chromium alloy, milled and cast titanium. For each group, 15 discoid specimens, 10 mm in diameter and 5 mm thick, were fabricated by either casting or milling. Five specimens of each group underwent one of three treatments: (1) no heat treatment, (2) a standard heat treatment, or (3) an extended heat treatment. Knoop hardness values were determined. Results indicated that the Knoop hardness of cast titanium was less than that of the cast titanium standard treatment group, which was less than the Knoop hardness of the cast titanium extended treatment group. Knoop hardness of milled titanium was less than that of the milled titanium standard treatment and milled titanium extended treatment groups. For the surface hardness profile, cast titanium showed a decreasing surface hardness as the distance from the surface of the specimen increased. No such trend was identified for the other groups tested.
Chromium Alloys↗
1H magnetic resonance imaging of freezing and thawing in freeze-tolerant frogs.
Proton magnetic resonance imaging (MRI) of the processes of freezing and thawing in the wood frog Rana sylvatica provided noninvasive and real-time analysis of the mode of ice propagation through the body of a freeze-tolerant vertebrate. MRI revealed a directional movement of ice from the exterior inward that required several hours to reach completion. Freezing in core organs such as liver, which produces and exports cryoprotectant, and heart, which circulates it, was delayed and occurred well after the organs were surrounded by extraorgan ice. Natural thawing was a very different process; thawing began uniformly throughout the body, but core organs melted more rapidly than peripheral ones, an adaptation that may be key to the early restoration of heartbeat and breathing. The images presented demonstrate the sensitivity and power of MRI and its potential to become a critical monitoring technology in the development of cryopreservation techniques for mammalian organ explants.
Acclimatization↗
Molecular biology of resistance to potato virus X in potato.
It has been proposed that plants express resistance to pathogens when the product of a resistance gene interacts with an elicitor molecule produced by the pathogen. Although there is one instance with tobacco mosaic virus (TMV) in which virus resistance is known to act through the same type of mechanism, it is not known whether this model accounts generally for resistance interactions with plant viruses. To address this issue the interactions of resistance genes in potato with potato virus X (PVX) have been analysed at the molecular level. PVX is an RNA virus that is affected by three different types of resistance locus in various potato cultivars. By using recombinant isolates of PVX, incorporating components of strains or mutant viruses able to overcome or avoid the effects of the resistance loci, we have identified different regions of the viral genome that determine the outcome of the resistance interaction. This information has allowed us to investigate the resistance in detail. For example, with the resistance specified by the Rx locus, it has been shown that the coat protein is an avirulence determinant and elicitor of an induced resistance. This resistance acts by reducing virus accumulation in the inoculated cell. Although the recognition component of the resistance is highly specific, the induced response is apparently non-specific and is effective against viruses unrelated to PVX in cells doubly inoculated with PVX and a second virus. The recognition function of Rx is also expressed in Gomphrena globosa which is a non-host plant of PVX. Based on these data, we propose that virus resistance fits the paradigm of resistance to fungal and bacterial pathogens and that there are similarities between the mechanism of cultivar specific resistance and non-host resistance to pathogen attack. Further analysis of the mechanism of the non-specific response phase may ultimately allow genetic engineering of broad-spectrum virus resistance in crop plants.
Plant Diseases↗
Expression of retinoic acid-responsive genes in primary neuroblastomas.
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Base Sequence↗
N-myc gene amplification in neuroblastoma determined by the polymerase chain reaction.
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Base Sequence↗
How much ethics is needed to make a good doctor?
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Education, Medical↗
Determination of N-myc gene amplification in neuroblastoma by differential polymerase chain reaction.
Determination of N-myc gene amplification, a powerful prognostic indicator in the childhood tumour, neuroblastoma, has routinely been performed by Southern analysis. We have developed a differential polymerase chain reaction (PCR) assay, in which the N-myc target gene is co-amplified with a control gene, glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Following electrophoresis, a ratio between the two PCR products within a given DNA sample is then determined by densitometry. This assay was applied to DNA isolated from 32 primary neuroblastoma tumours for which the N-myc status had previously been determined by Southern analysis. Following PCR, samples containing a single copy of the N-myc oncogene were clearly distinguishable from samples with N-myc gene amplification, based on an N-myc/GAPDH ratio of below or above 1.0, respectively. Linear regression indicated a highly significant relationship (R = 0.94; P < 0.0001) between N-myc copy number (Southern) and N-myc/GAPDH ratio (PCR). Serial dilution of N-myc amplified DNA with non-amplified control DNA indicated that the PCR assay was sufficiently sensitive to detect two-fold amplification. Moreover, such serial dilution allowed determination of N-myc copy number. The assay, which requires only small amounts of tissue and does not utilize 32P-radioactivity, therefore provides a rapid and sensitive alternative to Southern analysis.
Base Sequence↗
Treatment of lethal Pichinde virus infections in weanling LVG/Lak hamsters with ribavirin, ribamidine, selenazofurin, and ampligen.
A lethal Pichinde (An 4763 strain) virus infection was produced in 3-week-old random-bred Golden Syrian (LVG/Lak strain) hamsters inoculated intraperitoneally with virus, causing mortality in 6-9 days. High virus titers (> or = 10(7.5) cell culture infectious doses/g) were present in visceral organs, serum, brain and salivary glands near the time of death. Intraperitoneal treatments with ribavirin (10 and 32 mg/kg) and ribamidine (32, 100, and 320 mg/kg) for 10 days starting 24 h after virus challenge significantly decreased mortality and reduced virus titers by 100- to > 10,000-fold in liver, spleen, brain, and serum. Serum alanine aminotransferase (an indicator of liver damage) was also reduced in animals treated with the two compounds (ribavirin at 32 mg/kg; ribamidine at 100 and 320 mg/kg). Intraperitoneal selenazofurin (1-100 mg/kg per day for 10 days) and ampligen (0.5 and 5 mg/kg every other day for 5 injections) treatments provided neither protection from the lethal infection nor increased mean survival times. In fact, selenazofurin was overtly toxic, causing death of uninfected hamsters at 32 and 100 mg/kg. The random-bred LVG/Lak hamster appears to be a viable and cost-effective model for evaluating new therapies for arenavirus infections.
Animals↗
Relative involvement of protein kinase C and of the estrogen receptor in the cytotoxic action of a population of triphenylethylenes on MCF7 cells as revealed by correspondence factorial (CF) analysis.
A multivariate statistical method, correspondence factorial (CF) analysis, was used to examine the correlations among the protein binding and cell proliferation effects of a series of 36 di- and triphenylethylenes (DPEs and TPEs). The analysis was applied to a study which measured their competition for estradiol binding to cytosol estrogen receptor (ER), their influence on protein kinase C (PKC) activity under different conditions of enzyme activation, their ability to promote the growth of a breast cancer cell line and to inhibit growth at high concentrations (cytotoxicity). The CF analysis revealed several levels of correlation. First, it distinguished those molecules within the population that stimulated rather than inhibited PKC activity. Second, it made apparent a strong correlation between cytotoxicity and inhibition of Ca++ and phosphatidylserine-dependent PKC activity, which was most marked when the enzyme had been activated by diacylglycerol indicating that PKC inhibition under physiological conditions might contribute to the overall cytotoxicity of these compounds. Third, a lower level of correlation was established between competition for ER binding and cytotoxicity. Taken together, the results suggest that MCF7 cells might be most sensitive to a cytotoxic effect of TPEs (via PKC and other targets) when they at the same time decrease estrogen-stimulated proliferation via an ER-mediated antiestrogenic effect.
Animals↗
Mapping the facioscapulohumeral muscular dystrophy gene is complicated by chromsome 4q35 recombination events.
A gene responsible for facioscapulohumeral muscular dystrophy (FSHD) has been linked to polymorphisms on chromosome 4q35. Multipoint linkage analyses have placed this gene distal to all reported genetic markers on the chromosome. By using as a probe a clone isolated from a cosmid containing sequences related to a homeobox domain, de novo DNA rearrangements were reported in sporadic and familial cases of FSHD. Linkage analysis of an EcoRI polymorphism detected by this clone in twenty-four multigenerational FSHD families revealed recombinants between this marker and the disease with a recombination fraction of 0.05. Two families with apparent germline mosaicism were also identified.
Blotting, Southern↗
Mechanical properties of metal connectors soldered by gas torch versus an infrared technique.
PURPOSE: The ultimate tensile strength and percentage elongation of solder joints of three alloy systems were tested. MATERIALS AND METHODS: Solder joints were formed using either an infrared soldering machine or gas-oxygen torch. Intact solder materials were used as controls. RESULTS: There were no significant differences in percentage elongation among different treatment methods of the solders or among various solder materials. All intact solder materials possessed significantly higher ultimate tensile strength than the joints made with either method. For high-noble and noble alloy solders, there were no significant differences in ultimate tensile strength of joints made with either method. For base metal alloy solder, the ultimate tensile strength of joints made with the infrared technique was significantly higher than that made with the gas-oxygen torch technique. CONCLUSIONS: The infrared technique can be used as an alternative to the gas-torch technique for soldering high-noble and noble alloys. It is superior to the gas-torch technique for soldering a cobalt-chromium alloy.
Analysis of Variance↗
Putting the clock back 30 years: neonatal care since the 1991 NHS reforms.
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Hospitals, District↗