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At least 973 records · Page 54Linked to original sources
PubMed1982

Distribution of mannosamine and mannosaminuronic acid among cell walls of Bacillus species.

The distribution of mannosamine, mannosaminuronic acid, and the enzymes responsible for the formation of these saccharides was studied in nine species (18 strains) of Bacillus. Whereas UDP-N-acetylglucosamine 2-epimerase activity was detected in all of the strains examined, UDP-N-acetylmannosamine dehydrogenase, as well as the activity incorporating N-acetylmannosaminuronic acid residues from UDP-N-acetylmannosaminuronic acid into polymer, was found only in four strains of B. megaterium and one strain each of B. subtilis and B. polymyxa. The cell walls prepared from the six above-named strains were shown to contain mannosaminuronic acid in amounts of 135 to 245 nmol/mg. In contrast, mannosamine had a wide distribution. The cell walls from two strains of B. cereus and one strain each of B. circulans, B. polymyxa, B. sphaericus, and B. cereus subsp. mycoides contained mannosamine in amounts of 370 to 470 nmol/mg. In addition, the cell walls from five strains of B. subtilis, two strains of B. megaterium, and one strain each of B. cereus. B. coagulans, and B. licheniformis also contained this amino sugar in amounts as small as 10 to 35 nmol/mg. On the basis of analytical data, it is suggested that the mannosamine present in small amounts may be a common constituent of linkage units between peptidoglycan and other cell wall components such as glycerol teichoic acid.

Bacillus↗
PubMed1984

Structure of the terminal reducing heptasaccharide of polysaccharide 1 isolated from the Bordetella pertussis endotoxin.

The tetrasaccharide beta-D-glucopyranosyl-(1,3)-beta-D-glucopyranuronyl-(1, 2)-L-glycero-alpha-D-manno-heptopyranosyl-(1,5)-3-deoxy-D-manno-2- octulosonic acid was isolated after treatment of polysaccharide 1 of Bordetella pertussis endotoxin with nitrous acid. Taking into account previously identified di- and trisaccharide fragments and analytical data obtained for the intact polysaccharide 1, we present the structure of a heptasaccharide that is thought to represent the region immediately adjacent to the hydrophobic (lipid A) moiety of lipopolysaccharide 1 of the B. pertussis endotoxin. This heptasaccharide represents 50 to 60% of the complete polysaccharide structure.

Bordetella pertussis↗
PubMed1999

Use of pulsed-field gel electrophoresis for molecular epidemiologic and population genetic studies of Mycobacterium tuberculosis.

Pulsed-field gel electrophoresis (PFGE) is a powerful molecular biology technique which has provided important insights into the epidemiology and population biology of many pathogens. However, few studies have used PFGE for the molecular epidemiology of Mycobacterium tuberculosis. A laboratory protocol was developed to determine the typeability, stability, and reproducibility of PFGE typing of M. tuberculosis. Formal data-analytical techniques were used to assess the genetic diversity elucidated by PFGE analyses using four separate restriction enzymes and by IS6110 RFLP analyses, as well as to assess the concordance among these typing methods. One hundred epidemiologically characterized clinical isolates of M. tuberculosis were genotyped with four different PFGE enzymes (AseI, DraI, SpeI, and XbaI), as well as by RFLP analysis with IS6110. Identical patterns were found among 34 isolates known to be genetically related, suggesting that the PFGE protocol is robust and reproducible. Among 66 isolates representing population-sampled cases, heterozygosity and information content dependency estimates indicate that all five genotyping systems capture quantitatively similar levels of genetic diversity. Nevertheless, comparisons between PFGE analyses and IS6110 typing reveals that PFGE provided more discrimination among isolates with fewer than five copies of IS6110 and less clustering in isolates with five or more copies. The comparisons confirm the hypothesis that the resolution of IS6110 RFLP genotyping is dependent upon the number of IS6110 elements in the genome of isolates. The general concordance among the results obtained with four independent enzymes suggests that M. tuberculosis is a clonal organism. The availability of a robust genotyping technique largely independent of repetitive elements has implications for the molecular epidemiology of M. tuberculosis.

DNA Transposable Elements↗
PubMed2006

Cannabis and sport.

BACKGROUND AND OBJECTIVES: Cannabis is on the list of prohibited substances in the practice of sport, although its performance enhancing effect has not yet been proved. Its popularity among the younger generations as a social drug puts cannabis at the top of the list of compounds detected by the anti-doping laboratories accredited by the World Anti-Doping Agency worldwide. The management of the results of urine analysis is quite difficult for the medical and disciplinary committees not only because of the social use of the substance, but also because of the interpretation of the analytical data from urine samples. This paper gives an overview of what is presently known about cannabis in relation with the practice of sport. METHODS: Review of literature on the cannabis and exercise, its effect in the body, and the problems with interpretation of results when it is detected in urine. RESULTS: The paper outlines the major effects of cannabis in the context of its social use and its use for sport activities. The difficulties in the interpretation of urine sample analysis results because of the protracted excretion time of the main metabolite, long after the intake, are described. CONCLUSIONS: There is an urgent need for sport authorities to take measures necessary to avoid players misusing cannabis.

Cannabis↗
PubMed2002

The biochemical investigation of cases of hypoglycaemia: an assessment of the clinical effectiveness of analytical services.

AIM: To assess the extent to which biochemical analytical services contribute to the diagnosis and management of clinical cases of hypoglycaemia. METHODS: All cases of confirmed hypoglycaemia, referred during a six month period, were included in the survey. Questionnaires were sent to each referring laboratory requesting information on the clinical progress and current status of the patient. RESULTS: The level of influence exerted by analytical data was assigned in each case and those with similar outcomes combined. Identifiable case groups were: (1) Results not recorded in the patients' notes (15.7%). (2) Inappropriate requesting of insulin and C peptide measurements in cases of diabetes (11.4%). (3) Patient died soon after investigation (20.0%). (4) Patient recovered spontaneously (17.1%). (5) Patient received effective medical or surgical treatment (12.9%). (6) Patient awaiting or not requiring pathology based treatment (31.4%). (7) Inconclusive outcome prompting further investigation (5.7%). CONCLUSIONS: Within the timescale of the survey (approximately 12 months), positive progress had been made towards diagnosis and subsequent treatment in only 10% of cases. Another 30% were either awaiting some form of treatment or further diagnostic tests. The remaining 60% did not appear to benefit in any way from the biochemical investigations.

Adolescent↗
PubMed1985

Uranium-bearing stratiform organic matter in paleoplacers of the lower Huronian Supergroup, Elliot Lake--Blind River region, Canada.

The Elliot Lake-Blind River, Ontario, paleoplacer deposits in the basal Matineda Formation, lowermost member of the 2.25-2.45 Ga old Huronian Supergroup, contain organic matter chemically consistent with kerogen. This substance is also referred to as thucholite. Uranium ores and some gold occur here, and these minerals may be in close association with the kerogen. Two uraniferous and auriferous stratiform kerogens, obtained from the Denison Mines Limited's Denison mine and Rio Algom Limited's Stanleigh mine, have been analyzed by combined high-vacuum pyrolysis--gas chromatography--mass spectrometry and by neutron activation. The reflectances of these samples have also been determined. Related samples containing dispersed kerogen have been examined by backscattered scanning electron microscopy. The polymer-like matrix of the two stratiform kerogens consists of aromatic, alkyl aromatic hydrocarbon, and sulphur moieties and contains 20 and 32% uranium with gold abundances in the parts per billion range. The reflectances of the two kerogens are generally higher than those of the dispersed kerogens; the atomic H/C ratios of the former are approximately 0.6 and approximately 0.4. Backscattered scanning electron microscopy and petrographic observations reveal a complex diagenetic history. Stratigraphic position and supportive analytical data suggest that the stratiform kerogens were probably derived from ancient mats of cyanobacteria, subjected to various radiation-induced reactions, and, at least in part, were affected in a manner similar to the surrounding rocks. The latter experienced physical and chemical diagenetic reactions, which often caused repeated mineral fracturing and led to the local development of authigenic carbonates and feldspar. Some of the chemical nature and history of the stratiform kerogens resemble those of the Witwatersrand carbon seam kerogen.

Canada↗
PubMed1988

Families of lines: random effects in linear regression analysis.

Laboratory experiments often involve two groups of subjects, with a linear phenomenon observed in each subject. Simple linear regression as propounded in standard textbooks is inadequate to treat this experimental design, particularly when it comes to dealing with random variation of slopes and intercepts among subjects. The author describes several techniques that can be used to compare two independent families of lines and illustrates their use with laboratory data. The methods are described tutorially, compared, and discussed in the context of more sophisticated and more naive approaches to this common data-analytic problem. Technical details are supplied in APPENDIX A.

Adolescent↗
PubMed1999

Clearance and metabolism of starch foods in the oral cavity.

The presence of carbohydrates and organic acids was monitored in the oral cavity over a 3-hour period following the ingestion of six foods containing cooked starch (popcorn, potato chips, corn flakes, bread stick, hard pretzel and wheat cracker) and compared to a food containing sugar (chocolate-covered candy bar). Oral fluid samples were collected at 30-min intervals from five different tooth sites from 7 volunteers using absorbent paper points. Samples were analyzed for carbohydrates and organic acids using high-performance liquid chromatography. Analytical data for each food were pooled and compared to the results of the sugar food. The amount of lactic acid produced 30 min after ingestion was highest with the potato chips and lowest with the corn flakes. Potato starch contributed more readily to oral lactic acid production than wheat or corn starch. A direct linear relationship existed between lactic acid production and the presence of oral glucose produced from starch, which occurred via the metabolites maltotriose and maltose. Oral clearance of foods containing cooked starch proceeded significantly slower than that of the sugar food, thus contributing to a prolonged period of lactic acid production.

Acetic Acid↗
PubMed1990

The phosphorus content of lysosomes in hepatocytes and Kupffer cells. A study using electron-spectroscopic imaging.

In the present study, the distribution of phosphorus was analyzed within lysosomes of hepatocytes, Kupffer cells and mast cells in untreated liver tissue of mice by the use of electron-spectroscopic imaging, a new electron-microscopical method which combines microanalysis with ultrastructural representation and allows to image the spatial distribution of light elements such as O, N or P in cells and tissues. The obtained analytical data unfolded marked differences regarding the phosphorus content of lysosomes within hepatocytes. Whereas peribiliary bodies always included phosphorus highly condensed in a coarse-granular distribution, the lysosomes apart from biliary capillaries contained different amounts of phosphorus, varying from high concentration to moderate and negligible amounts appearing as dust-like powder in the lysosomal interior. In contrast, the lysosomes of Kupffer cells always comprised phosphorus in high density and similar concentration as it is found in cytoplasmic ribosomes. These results confirm a pronounced and unexpected heterogeneity regarding the elemental composition of lysosomes in hepatocytes and Kupffer cells. It may be assumed that this heterogeneity is not accidental but based on differences in the functional state of lysosomes and the activity of their hydrolytic enzymes.

Animals↗
PubMed1977

Fosfomycin in pneumococcal meningitis.

A study has been made of 12 patients with pneumococcal meningitis with ages ranging from 12 months to 59 years. In all cases pneumococcus was isolated in the cerebrospinal fluid (CSF). Seventeen pneumococci were studied for their sensitivity to fosfomycin, ampicillin and gentamicin, including their MIC. All were sensitive to fosfomycin and ampicillin and 7 to gentamicin. On the other hand there has also been made a study of the interaction between fosfomycin plus ampicillin and fosfomycin plus gentamicin. The concentration of antibiotics in plasma and CSF had been determined. The association of fosfomycin to penicillin or ampicillin was also studied in some cases, depending on whether the patient was younger or older than 2 years, and in other cases, the association of fosfomycin with gentamicin. The concentrations of antibiotics in the CSF varied according to the stage of evolution of the meningitis. As regards clinical results, 10 cures and 2 failures have been obtained. The pneumococcus was eradicated from the CSF in all cases, including the two failures, in the control carried out 2-3 days after beginning of treatment, the rest of the analytical data of the CSF became normal within 5 and 17 days treatment.

Adult↗
PubMed1988

Patterns of fluoride distribution on the surface of a tooth fragment after clinical treatment with fluoride gel.

This paper describes site-to-site variations in fluoride concentration in the surface region of a tooth fragment sent from a patient who, following radiation therapy, had been repeatedly treated with fluoride gel. The fluoride content of the tooth surface was determined with the intention of establishing the extent to which the treatment had enhanced the fluoride content of the tooth surface. The work illustrates the difficulties in the choice of a suitable sampling site and the importance of adopting a suitable sampling technique. It highlights, once again, some of the problems encountered in attempting to interpret analytical data about fluoride levels in tooth surfaces.

Dental Enamel↗
PubMed1997

A method for the quantitative site-specific study of the biochemistry within dental plaque biofilms formed in vivo.

The study of plaque biofilms in the oral cavity is difficult as plaque removal inevitably disrupts biofilm integrity precluding kinetic studies involving the penetration of components and metabolism of substrates in situ. A method is described here in which plaque is formed in vivo under normal (or experimental) conditions using a collection device which can be removed from the mouth after a specified time without physical disturbance to the plaque biofilm, permitting site-specific analysis or exposure of the undisturbed plaque to experimental conditions in vitro. Microbiological analysis revealed plaque flora which was similar to that reported from many natural sources. Analytical data can be related to plaque volume rather than weight. Using this device, plaque fluoride concentrations have been shown to vary with plaque depth and in vitro short-term exposure to radiolabelled components may be carried out, permitting important conclusions to be drawn regarding the site-specific composition and dynamics of dental plaque.

Bacterial Adhesion↗
PubMedDate not supplied

Cytologic features of pheochromocytoma and retroperitoneal paraganglioma: a morphologic and immunohistochemical study of 13 cases.

OBJECTIVE: To review the cytologic features and potential pitfalls of pheochromocytoma and retroperitoneal paraganglioma and to evaluate complications of the aspiration procedure and the diagnostic utility of immunocytochemistry. STUDY DESIGN: We reviewed 15 cytologic specimens from 12 patients with 13 tumors (1 bilateral case). Ten were adrenal (pheochromocytomas) and 3 extraadrenal paragangliomas. Eleven specimens were from fine needle aspiration (FNA) procedures that were performed in collaboration with radiologists using 23-25-gauge needles. In 3 patients the cytologic material was obtained during intraoperative diagnosis. Immunocytochemistry was performed on alcohol-fixed smears. RESULTS: Two aspirates were hypocellular, while the remainder were cellular. Cells were distributed singly or formed discohesive groups. When present, cytoplasm was abundant and ill defined. Most cells had an eccentric nucleus and plasmacytoid morphology. Nuclear pleomorphism, binucleation and multinucletaion, naked nuclei and intranuclear preudoinclusions were common findings. In 2 cases a lipid background was seen focally. Evident cytoplasmic immunoexpression of synaptophysin or chromogranin was detected in the 10 cases analyzed. One patient developed a hypertensive episode during the FNA procedure. It was controlled medically without complications. CONCLUSION: When adequate cytologic material is present, the recognition of pheochromocytoma and extraadrenal paraganglioma is possible. Together with morphology, immunocytochemical studies allow a specific preoperative diagnosis. Scarce material can be a source of diagnostic errors. FNA of pheochromocytomas is not necessarily contraindicated. When analytic data are not diagnostic, FNA may follow. Aspiration must be performed in an area equipped with the therapeutic tools necessary to control a pheochromocytoma crisis.

Adolescent↗
PubMed1994

Discrepancies between longitudinal and cross-sectional change in ventilatory function in 12 years of follow-up.

We compared the age dependence of cross-sectional and longitudinal changes in ventilatory function. FEV1, FVC, and data on chronic respiratory symptoms were obtained from 4,395 adults in a longitudinal survey of normal populations in two different areas in the Netherlands. They participated in up to five surveys at 3-yr intervals between 1972 to 1973 and 1984 to 1985. The ventilatory function in the oldest cohorts is substantially lower than might have been expected from the longitudinal change in the youngest cohorts. This holds for males and females, smokers and nonsmokers, subjects with or without symptoms, and for both survey populations. The robustness of the findings is demonstrated by various data-analytic strategies or omitting one or two of the five surveys from the analysis. Selective loss to follow-up cannot explain the discrepancy. It is concluded that the main differences between our longitudinal and cross-sectional findings may be due to a cohort effect. The implication is that in longitudinal studies of populations at risk, reference equations based on cross-sectional surveys may overestimate longitudinal change and hence lead to underestimating effects of exposure. Similarly, in clinical studies, accelerated decline in ventilatory function may be underrated if it is compared with cross-sectional standards. In older people at any one age the ventilatory function seems to improve in successive birth cohorts.

Adult↗
PubMed1994

A longitudinal study of Alzheimer's disease: measurement, rate, and predictors of cognitive deterioration.

OBJECTIVE: This study measured the annual rate of cognitive change in patients with Alzheimer's disease and determined the effects of clinical variables on that rate. It also compared the ability of two cognitive scales to measure change over the entire range of dementia severity. METHOD: The cognitive subscale of the Alzheimer's Disease Assessment Scale and the Blessed test for information memory and concentration were given to 111 patients with Alzheimer's disease and 72 nondemented elderly comparison subjects at 6-month intervals for up to 90 months. Longitudinal changes in scores on the cognitive subscale were measured with several different methods of data analysis. RESULTS: For the patients with Alzheimer's disease, the annual rate of change in cognitive subscale scores showed a quadratic relationship with dementia severity in which deterioration was slower for mildly and severely demented patients than for patients with moderate dementia. Gender, age at onset, and family history of dementia had no effect on the rate of cognitive deterioration. The comparison group showed a slight improvement in cognitive performance over time. All data analytic methods gave similar results. The cognitive subscale of the Alzheimer's Disease Assessment Scale was more sensitive to change in both mild and severe dementia than was the Blessed test. CONCLUSIONS: These results suggest that cognitive deterioration is slow during the early and very late stages of Alzheimer's disease and more rapid during the middle stages. No clinical variables other than degree of cognitive impairment and previous rate of cognitive decline predicted rate of deterioration. These results have implications for treatment trials and attempts to identify subgroups.

Adult↗
PubMed2005

The case for practical clinical trials in psychiatry.

OBJECTIVE: Clinical trials in psychiatry frequently fail to maximize clinical utility for practicing clinicians, or, stated differently, available evidence is not perceived by clinicians (and other decision makers) as sufficiently relevant to clinical practice, thereby diluting its impact. To attain maximum clinical relevance and acceptability, researchers must conduct clinical trials designed to meet the needs of clinicians and others who are making decisions about patients' care. The authors present the case for psychiatry's adoption of the practical clinical trials model, which is widely used in research in other areas of medicine. METHOD: The authors outline the characteristics and scope of practical clinical trials, give examples of practical clinical trials, and discuss the challenges of using the practical clinical trials model in psychiatry, including issues of funding. RESULTS: Practical clinical trials, which are intended to provide generalizable answers to important clinical questions without bias, are characterized by eight key features: a straightforward clinically relevant question, a representative sample of patients and practice settings, sufficient power to identify modest clinically relevant effects, randomization to protect against bias, clinical uncertainty regarding the outcome of treatment at the patient level, assessment and treatment protocols that enact best clinical practices, simple and clinically relevant outcomes, and limited subject and investigator burden. CONCLUSIONS: To implement the practical clinical trials model in psychiatry will require stable funding for network construction and maintenance plus methodological innovation in governance and trial selection, assessment, treatment, data management, site management, and data analytic procedures.

Adolescent↗
PubMed1988

Patient's sleep on the analytic couch.

Published reports about sleep on the couch have primarily emphasized its preoedipal (especially oral) determinants and defensive purposes. A detailed case is presented in which sleep became the central symptom of the transference neurosis. The primary determinants of the symptom were from the phallic-oedipal stage of development. Like other symptoms, the sleep symptom was a reliving of earlier experiences and was analyzed primarily through the transference. The analytic data from the case are used to illustrate resistance as an ally in the psychoanalytic process.

Acting Out↗
PubMed1991

Sadomasochism in the neuroses conceived of as a pathological compromise formation.

Masochistic phenomena in adults are discussed as derivatives of conscious and/or unconscious fantasies. These masochistic fantasies are always associated with conscious and/or unconscious narcissistic and sadistic fantasies. These fantasies, like all fantasies in adults, are conceived of as compromise formations. After a selected review of the literature, analytic data are presented to highlight the clinical advantages of a contemporary elaboration of the structural hypothesis for the understanding of sadomasochistic and sadonarcissistic phenomena.

Adult↗