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PubMed1961

Enzyme systems in the Mycobacteria. XI. Evidence for a functional glycolytic system.

Bastarrachea, Fernando (University of Wisconsin, Madison), David G. Anderson, and Dexter S. Goldman. Enzyme systems in the mycobacteria. XI. Evidence for a functional glycolytic system. J. Bacteriol. 82:94-100. 1961.-Cell-free extracts of the H37Ra strain of Mycobacterium tuberculosis contain the enzymes, aldolase, phosphohexokinase, phosphohexoisomerase, and phosphoglucomutase. The first three enzymes have been purified; the characteristics of all these enzymes have been studied. The enzymes are similar to those isolated from animal tissue. A functional glycolytic system in the mycobacteria provides a mechanism for the formation of other metabolites from glycerol.

Animals↗

PubMed1961

Some factors which affect the initiation of growth of Cryptococcus neoformans.

Howard, Dexter H. (University of California, Los Angeles). Some factors which affect the initiation of growth of Cryptococcus neoformans. J. Bacteriol. 82:430-435. 1961.-The observation that a strain of Cryptococcus neoformans failed to grow in a medium containing normal human serum led to an investigation of some of the physiological factors controlling initiation of growth by this fungus. The data presented show that the growth of C. neoformans is markedly inhibited in media with initial pH values slightly above neutrality. The growth of four strains of the fungus was completely suppressed in peptone broth at pH values above 8. The growth of two strains was partially inhibited at a pH of 7.3. Two other strains grew well at 7.3, but were partially inhibited at pH 7.5. The growth in media at pH values which partially inhibited multiplication was granular in appearance. Microscopically the granules were composed of clumps of yeast cells. The possibility is suggested that pH may exert a portion of its effect on the growth of C. neoformans by influencing those factors which affect the stability of the cells in suspension. At a temperature of 25 C, growth of the fungus was initiated in media with a pH which suppressed growth at a temperature of 37 C. Under the experimental conditions employed in these studies, proteose peptone no. 3 (Difco) serves as both a carbon and a nitrogen source. However, glucose, which is assimilated by C. neoformans in contrast to lactose, permitted the growth of the fungus at pH values which suppressed growth in the absence of the sugar. Since weakly buffered media, containing filtered, normal human serum, have an alkaline reaction higher than that shown to suppress the growth of C. neoformans, it was concluded that this factor was primarily responsible for the failure of the fungus to reproduce in tissue culture media. However, it is also possible to show that even under optimal pH conditions normal human serum exerts an anticryptococcal effect. This activity of human serum was relatively heat-stable and was expressed only in high concentrations of serum. Serum adsorbed with viable cells of C. neoformans also inhibited the growth of the fungus, but a partially purified globulin fraction of serum was not inhibitory. The data are discussed in relation to the work of other investigators.

Cryptococcus↗

PubMed1962

Substrate specificity of a glucose permease of Escherichia coli.

Rogers, Dexter (Utah State University, Logan) and Shon-hua Yu. Substrate specificity of a glucose permease of Escherichia coli. J. Bacteriol. 84:877-881. 1962.-A study was made of d-galactose uptake by galactose-negative Escherichia coli strain A (Weigle). Uptake probably occurred through a glucose-permease system, because d-glucose and a variety of nonmetabolizable glucose derivatives inhibited the accumulation of galactose and were themselves accumulated. d-Fructose did not inhibit galactose uptake. 6-Deoxy-d-galactose (d-fucose) was taken up by a different permease system. The glucose permease apparently favored pyranoses, and it required the 6-hydroxyl group of the substrate to a greater extent than any of the other hydroxyl groups. Although much of the absorbed glucose-permease substrate was recovered in the free form, a significant amount was recovered as the 6-phosphate ester. Depending on the conditions employed to study uptake, the 6-phosphate ester could amount to as much as 60% of the absorbed galactose.

Enzymes↗

PubMed1963

COMPARISON OF STRAINS OF SPOROTRICHUM SCHENCKII ISOLATED FROM NATURE.

Howard, Dexter H. (University of California, Los Angeles) and G. F. Orr. Comparison of strains of Sporotrichum schenckii isolated from nature. J. Bacteriol. 85:816-821. 1963.-Several strains of fungi, tentatively considered to be members of the genus Sporotrichum, have been isolated from soil and from other sources in nature. The striking morphological similarity of these isolates to strains of S. schenckii led to a comparative study of their biological properties. Nine strains of Sporotrichum from nature were compared with twelve strains of S. schenckii isolated from cases of clinical sporotrichosis. The nine saprophytic isolates were indistinguishable microscopically and macroscopically from strains of pathogenic S. schenckii when cultures were prepared on a variety of media incubated at 28 C. Only two of the nine saprophytic isolates were able to grow at 37 C. These two strains partially converted, at this temperature, to a yeast-cell phase of growth. The blastospores comprising this phase of growth were similar to those produced by S. schenckii under the same circumstances. Six of the nine saprophytes were essentially avirulent for mice. The remaining three strains had a very limited capacity to produce disease in experimental animals. The isolates are currently regarded as variants of S. schenckii.

Animals↗

PubMed1963

TURBIDITY CHANGE DURING GLUCOSE PERMEATION IN ESCHERICHIA COLI.

Rogers, Dexter (Utah State University, Logan) and Shon-Hua Yu. Turbidity change during glucose permeation in Escherichia coli. J. Bacteriol. 85:1141-1149. 1963.-In contrast to the normal turbidity decrease, which was observed at pH 5.5, the turbidity of suspensions of Escherichia coli strain A (Weigle) increased during uptake of glucose permease substrates when uptake was studied at pH 6.5. Although the turbidity increase at pH 6.5 was the reverse of the expected change, it correlated with the uptake of substrate. During the later phase of permeation at pH 6.5, both uptake of substrate and turbidity change were reversed. We suggest that the observed turbidity response indicated the accumulation of substrate at the cell membrane when the mechanism for releasing substrate to the cytoplasm was inhibited at pH 6.5. Under this condition, uptake of substrate did not cause swelling because the substrate was osmotically inactive, since it may have been bound to the membrane. Permeability was observed to be susceptible to modification by prior treatment with substrate, by aging in the presence of chloramphenicol, and by treatment with dinitrophenol. Permeation and turbidity change are discussed in terms of a proposed phosphorylative mechanism of glucose transport.

Biological Transport↗

PubMed1963

ENZYME SYSTEMS IN THE MYCOBACTERIA. XV. INITIAL STEPS IN THE METABOLISM OF GLYCEROL.

Goldman, Dexter S. (Veterans Administration Hospital, Madison, Wis.). Enzyme systems in the mycobacteria. XV. Initial steps in the metabolism of glycerol. J. Bacteriol. 86:30-37. 1963.-In cell-free extracts of strain H37Ra of Mycobacterium tuberculosis, glycerol is metabolized first by oxidation to dihydroxyacetone. A kinase was partially purified and shown to phosphorylate dihydroxyacetone; in the presence of the glyceraldehyde-3-phosphate dehydrogenase system, the product of the kinase reaction was further oxidized to 3-phosphoglycerate. The role of alpha-glycerol phosphate in the metabolism of strain H37Ra is discussed.

Glyceric Acids↗

PubMed1963

BIOSYNTHESIS OF RIBOSE AND DEOXYRIBOSE IN PSEUDOMONAS SACCHAROPHILA.

Fossitt, Dexter D. (University of Michigan, Ann Arbor), and I. A. Bernstein. Biosynthesis of ribose and deoxyribose in Pseudomonas saccharophila. J. Bacteriol. 86:1326-1331. 1963.-The biosynthesis of ribose and deoxyribose in Pseudomonas saccharophila was studied by radioisotope-tracer techniques. Patterns of C(14) in ribose isolated from the nucleic acids of cells grown on labeled glucose suggested that pentose was made by the pathway involving transaldolase and transketolase. When cells were grown on radioactive gluconate, the tracer patterns indicated the possibility of a new pathway for the biosynthesis of ribose. Isotopic patterns in deoxyribose, in general, were consistent with the pathway involving reduction of ribonucleotides to deoxyribonucleotides. Certain aspects of the data, however, were not explained by this known pathway.

Carbohydrate Metabolism↗

PubMed1964

INTRACELLULAR BEHAVIOR OF HISTOPLASMA CAPSULATUM.

Howard, Dexter H. (University of California, Los Angeles). Intracellular behavior of Histoplasma capsulatum. J. Bacteriol. 87:33-38. 1964.-The tinctorial characteristics and intracellular generation time of Histoplasma capsulatum within mouse histiocytes maintained in tissue culture were studied. The appearance of viable and nonviable cells of H. capsulatum was observed after staining with the May Grunwald-Giemsa, Methenamine Silver, and Periodic acid-Schiff (PAS) procedures. Death of the fungus, either induced by heat or occurring naturally in saline suspension, caused a loss of nuclear differentiation. This loss was not accompanied by changes in the PAS or Silver staining capacities of the cell walls of the fungus. There was no tinctorial evidence for intracellular death of H. capsulatum in normal mouse histiocytes. The intracellular generation time of the fungus was estimated to be 10.3 +/- 1.5 hr, and was not affected by the age of the histiocytes. The generation time was approximately the same in histiocytes from Webster-Swiss and A/J mice.

Animals↗

PubMed1964

SOLUBILIZATION OF PROTEIN ACCOMPANYING LOSS OF PERMEABILITY OF ESCHERICHIA COLI.

Rogers, Dexter (Utah State University, Logan). Solubilization of protein accompanying loss of permeability of Escherichia coli. J. Bacteriol. 88:279-292. 1964.-Two methods were studied for altering glucose permeability of Escherichia coli, and changes in protein and phosphorus composition were compared with changes in permeability. Protein was solubilized by incubating the cells at pH 7.3 in the presence of chloramphenicol, under conditions known to destabilize permeability. No protein was solubilized at pH 5.3, where permeability is stable. The solubilized protein was one of the first proteins to be extracted from the cells under mild conditions. Permeability was also altered by varying the culture age. It was maximal for logarithmic growth phase cultures, and it decreased rapidly in cultures in the stationary growth phase. Permeability correlated with the ratio of insoluble protein to soluble protein of the cells. Chromatographic analysis of an extract of cells treated at pH 7.3 revealed the presence of one additional protein fraction that was not present in an extract of cells treated at pH 5.3. The solubilized protein was precipitable with uranyl ion, which is a non-penetrating inhibitor of glucose transport in intact cells. Changes in phosphorus composition preceded changes in permeability and protein composition. These changes suggested that a phosphorus metabolite might contribute to the activity of the permeation process.

Bacterial Proteins↗

PubMed1965

INTRACELLULAR GROWTH OF HISTOPLASMA CAPSULATUM.

Howard, Dexter H. (University of California, Los Angeles). Intracellular growth of Histoplasma capsulatum. J. Bacteriol. 89:518-523. 1965.-Under a variety of experimental conditions, the generation time of Histoplasma capsulatum in mammalian histiocytes was remarkably constant. The rate of intracellular growth of five different isolates of H. capsulatum was very similar. The generation time of the fungus within guinea pig cells was nearly the same as it was within mouse cells under comparable conditions. Preliminary exposure of yeast cells to specific antibodies and complement did not affect intracellular proliferation of the fungus during the first 24 hr after phagocytosis by mouse histiocytes. The rate of growth of the fungus within cells from immunized mice and guinea pigs was comparable to that in cells from normal animals. This latter result was not altered by preliminary exposure of the fungus to hyperimmune serum and complement.

Animals↗

PubMed1965

REVERSIBLE EFFECT OF BICARBONATE ON THE INHIBITION OF MYCOBACTERIAL AND YEAST TRANSGLUCOSYLASES BY MYCORIBNIN.

Lornitzo, Frank A. (Veterans Administration Hospital, Madison, Wis.), and Dexter S. Goldman. Reversible effect of bicarbonate on the inhibition of mycobacterial and yeast transglucosylases by mycoribnin. J. Bacteriol. 89:1086-1091. 1965.-The transglucosylase which catalyzes the formation of trehalose-6-phosphate from uridine diphosphate (UDP)-glucose and glucose-6-phosphate was purified from cell-free extracts of Mycobacterium tuberculosis H37Ra. During the purification procedure, the transglucosylase loses its sensitivity to mycoribnin, an inhibitor also found in these extracts. Sensitivity of the transglucosylase to mycoribnin is regained when the bicarbonate concentration of either enzyme or mycoribnin preparations is reduced to about 0.01 mm; sensitivity to mycoribnin is lost when low concentrations (< 1 mm) of bicarbonate are present in the reaction mixture. Transglucosylase preparations retain their bicarbonate-induced insensitivity to mycoribnin after dilution to a bicarbonate concentration which is ineffective for the initial conversion to insensitivity. The transglucosylases of brewer's yeast and of physiologically young (9-day) H37Ra cells, previously reported as insensitive to mycoribnin, have been partially purified. If bicarbonate is excluded from these preparations, the transglucosylases become sensitive to mycoribnin; bicarbonate abolishes this sensitivity. The H37Ra transglucosylase is specific for UDP-glucose and glucose-6-phosphate as substrates. UDP-galactose does not serve as a glycosyl donor; galactose-6-phosphate, ribose-5-phosphate, and glucose-1-phosphate do not act as glucosyl acceptors. Oligoribonucleotide analogues of mycoribnin do not inhibit substantially the H37Ra transglucosylase.

Bicarbonates↗

PubMed1984

Comparative evaluation of the Eiken and API 20E systems and conventional methods for identification of members of the family Enterobacteriaceae.

To evaluate the accuracy and utility of the Eiken Systek No. 1 (Eiken system; Eiken Chemical Co., Ltd., Tokyo, Japan), we conducted a clinical comparison, with 345 Enterobacteriaceae isolates, of the Eiken System with API 20E (Analytab Products, Inc., Plainview, N.Y.) and conventional methods. The Eiken system is a 21-biochemical-test battery tray stored at 25 degrees C and inoculated in one step. It is similar to the API 20E except that the Eiken system contains malonate, adonitol, and maltose; lacks gelatin, sucrose, melibiose, amygdalin, and arabinose; and uses reagent strips instead of liquid reagents. The API 20E and Eiken systems correctly identified 339 (97.7%) and 276 (79.5%), respectively, and misidentified 3 (0.9%) and 13 (3.7%), respectively, of the isolates. There were no identification codes for 5 (1.4%) organisms with the API 20E and 58 (16.7%) organisms with the Eiken system; of these latter unidentified organisms, 42 were identified as Proteus spp., Morganella sp., and Providencia rettgeri by conventional methods. There was no significant difference between the two rapid systems in total time required for inoculation and reading. Modifications for interpretation of decarboxylase and oxidase tests were needed for the Eiken system, and manipulation of reagent strips required considerable dexterity. However, the Eiken system was easier to inoculate than the API 20E, and, with minor increases in the data base to include more of the Proteus and Morganella spp. and P. rettgeri, the system should be reliable for identification of members of the family Enterobacteriaceae.

Computers↗

PubMed2004

Motor skills in adolescents with low birth weight.

BACKGROUND: Minor motor problems have been reported in low birthweight children, but few studies have assessed motor skills in adolescents. OBJECTIVE: To examine the prevalence of motor problems in adolescents with low birth weight. METHOD: Fifty four very low birthweight (VLBW: birth weight < or = 1500 g), 59 term small for gestational age (SGA: birth weight < 10th centile), and 83 control (birth weight > or = 10th centile at term) children were assessed with the Movement assessment battery for children (Movement ABC) at the age of 14 in a population based study. RESULTS: One in four VLBW children (odds ratio (OR) 9.3, 95% confidence interval (CI) 2.5 to 34.5) and one in six SGA children (OR 4.7, 95%CI 1.2 to 18.4) had motor problems compared with controls (3.7%). There were no sex differences in motor problems in the VLBW group, and the increased risk was consistent across the continuum of the Movement ABC. For SGA children, the increased risk of motor problems was particularly in manual dexterity in boys. CONCLUSION: VLBW and SGA adolescents have increased risk of motor problems compared with control children.

Adolescent↗

PubMed1992

Impaired motor function (clumsiness) in 5 year old children: correlation with neonatal ultrasound scans.

All 155 surviving children from a cohort of 200 very low birthweight infants originally studied in 1984-5 were traced. These infants had careful sequential ultrasound examinations in the neonatal period. The children were examined again at entry into school at 5 years of age. The test of motor impairment (TOMI) and the vocabulary subscale of the Wechsler preschool and primary scale of intelligence (WPPSI) were administered to 152 of the index cohort and 144 control children of the same age in the same class at school. Twelve of the cohort had cerebral palsy, but eight of these were in mainstream schools. The index group scored significantly higher on both the TOMI and the WPPSI subscale compared with the controls. The index cases were subdivided on the basis of their neonatal ultrasound scans into four groups: group 1, consistently normal; group 2, 'prolonged flare'; group 3, germinal matrix haemorrhage-intraventricular haemorrhage (GMH-IVH), without parenchymal haemorrhage, but no evidence of prolonged flare; and group 4, both GMH-IVH and prolonged flare. The group of index children with consistently normal ultrasound scans had a higher TOMI and lower WPPSI compared with their controls. There was a statistically significant increase in the TOMI subscore 1 (manual dexterity) in group 4 infants compared with group 1, but not differences between the other groups. Regression analysis suggests that neither prolonged flare nor GMH-IVH has an important individual contribution to the variation, but the low birth weight does have a significant relationship with motor impairment. It appears that relatively minor ultrasound appearances such as prolonged flare and GMH-IVH are associated with motor impairment (clumsiness) at 5 years, but this has a small effect compared with low birth weight.

Cerebral Palsy↗

PubMed2006

More relevant, precise, and efficient items for assessment of physical function and disability: moving beyond the classic instruments.

OBJECTIVES: Patient reported outcomes (PROs) have become standard study endpoints. However, little attention has been given to using item improvement to advance PRO performance which could improve precision, clarity, patient relevance, and information content of "physical function/disability" items and thus the performance of resulting instruments. METHODS: The present study included 1860 physical function/disability items from 165 instruments. Item formulations were assessed by frequency of use, modified Delphi consensus, respondent judgement of clarity and importance, and item response theory (IRT). Data from 1100 rheumatoid arthritis, osteoarthritis, and normal ageing subjects, using qualitative item review, focus groups, cognitive interviews, and patient survey were used to achieve a unique item pool that was clear, reliable, sensitive to change, readily translatable, devoid of floor and ceiling limitations, contained unidimensional subdomains, and had maximal information content. RESULTS: A "present tense" time frame was used most frequently, better understood, more readily translated, and more directly estimated the latent trait of disability. Items in the "past tense" had 80-90% false negatives (p<0.001). The best items were brief, clear, and contained a single construct. Responses with four to five options were preferred by both experts and respondents. The term physical function may be preferable to the term disability because of fewer floor effects. IRT analyses of "disability" suggest four independent subdomains (mobility, dexterity, axial, and compound) with factor loadings of 0.81-0.99. CONCLUSIONS: Major improvement in performance of items and instruments is possible, and may have the effect of substantially reducing sample size requirements for clinical trials.

Activities of Daily Living↗

PubMed1984

Measures of functional ability (disability) in arthritis in relation to impairment of range of joint movement.

In the World Health Organisation's supplementary classification of the consequences of disease a distinction is made between impairments, such as are related to the site and nature of joint involvement, and any disabilities in everyday activities to which these may give rise. This paper considers the application of these ideas to people with arthritis by examining the extent of graded relationship between individual impairments, reflected by limitations in the range of joint movement, and the number or type of disabilities. Ninety-five people with three different types of arthritis were studied. A 41-item disability questionnaire was completed. Most of the variation was described by only 24 of the latter items. These fell into five broad functional groups--predominantly concerned with mobility, bending down, manual dexterity, bending the arm, and reaching above the head. The constituent activities could be scaled in order of difficulty of accomplishment. Aggregated scores for each of the functional groups were correlated with observed ranges of motion in relevant joints, and the ordering of difficulty was related to decreasing ranges of movement. These findings shed light on the genesis of disability and have implications for the development of more sensitive, specific, and simple methods of assessment in rheumatology. Appreciation of how disability relates to the localisation of disease manifestations provides a means for evaluating current methods of functional assessment and exposes potential biases in such appraisals.

Adult↗

PubMed1992

Physiotherapy intervention late after stroke and mobility.

OBJECTIVE: To determine whether the intervention of a physiotherapist improved mobility in patients seen more than one year after stroke. DESIGN: Randomised crossover trial comparing two groups offered intervention by a physiotherapist, one immediately after entry into the trial and the other after a delay of three months. The intervention consisted of identifying problems and offering advice and help to solve the problems. SETTING: Patients' homes in Oxfordshire. SUBJECTS: Patients who had reduced mobility due to a stroke more than one year before entry; 60 were recruited from a community stroke register and 34 in other ways. MAIN OUTCOME MEASURES: Standard measures of mobility including gait speed, functional ambulation categories, the Nottingham extended activities of daily living index, and individual items from the Barthel activities of daily living index and the Frenchay activities index. Measures of manual dexterity, depression, and anxiety were used as controls. RESULTS: 94 patients entered the trial and 49 were randomised to immediate and 45 to delayed physiotherapy; 89 were compared at the crossover point. At randomisation the two groups were comparable. At three months the group given early therapy showed an improvement in gait speed whereas the untreated group had declined (differences of -3.9 v 6.4 s to walk 10 m; p less than 0.01); between three and six months the group given delayed therapy showed improvement and the previously treated group declined (differences of 6.5 v -3.9 s to walk 10 m; p less than 0.01). A 9% (95% confidence interval 0% to 18%) decrease in time taken to walk 10 m was associated with treatment and a 12% (2% to 19%) increase when patients were untreated. Other measures did not change significantly. CONCLUSION: Intervention of an experienced physiotherapist late after stroke specifically improves mobility, albeit by a small amount, but the effects do not seem to be maintained, perhaps because there is an underlying decline in mobility in these patients. Gait speed offers a simple and sensitive measure of outcome.

Activities of Daily Living↗

PubMed1994

Life expectancy in children with cerebral palsy.

OBJECTIVE: To determine life expectancy of children with cerebral palsy. DESIGN: Cohort analysis, by means of register compiled from multiple sources of ascertainment, of all children with cerebral palsy born during 1966-84 to mothers resident in Mersey region. Status of children was determined by flagging through NHS central register. SUBJECTS: 1258 subjects with idiopathic cerebral palsy, of whom 1251 were traced and included in analysis. MAIN OUTCOME MEASURES: Effect of functional ability (ambulation, manual dexterity, and mental ability), sex, birth weight, and gestational age on survival. RESULTS: 20 year survival for whole cohort was 89.3% for females and 86.9% for males. For subjects with no severe functional disabilities 20 year survival was 99% (95% confidence interval 98% to 100%), while subjects severely disabled in all three functional groups had 20 year survival of 50% (42% to 58%). Subjects with birth weight < or = 2500 g had 20 year survival of 92% (89% to 95%), while those with birth weight > 2500 g had survival of 87% (84% to 89%). Subjects with gestational age of > 37 weeks had 20 year survival of 93% (91% to 96%), while those with gestational age > or = 37 weeks had survival of 85% (83% to 88%). Birth weight and gestational age were less predictive of survival than functional disability. Best statistical model used gestational age and number of severe functional disabilities as predictors. CONCLUSIONS: Life expectancy of this cohort of children with cerebral palsy was greater than has been suggested in some previous studies. This has important implications for social, educational, and health services.

Birth Weight↗