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Biomedical subjects

A Pratt

Publications and source records attributed to A Pratt.

17 recordsLinked to original sources
PubMed2006

Quantitative oral dosing of water soluble and lipophilic contaminants in the Japanese medaka (Oryzias latipes).

Quantitative oral dosing in fish can be challenging, particularly with water soluble contaminants, which can leach into the aquarium water prior to ingestion. We applied a method of bioencapsulation using newly hatched brine shrimp (Artemia franciscana) nauplii to study the toxicokinetics of five chlorinated and brominated halogenated acetic acids (HAAs), which are drinking water disinfection by-products. These results are compared to those obtained in a previous study using a polybrominated diphenyl ether (PBDE-47), a highly lipophilic chemical. The HAAs and PBDE-47 were bioencapsulated using freshly hatched A. franciscana nauplii after incubation in concentrated solutions of the study chemicals for 18 h. Aliquots of the brine shrimp were quantitatively removed for chemical analysis and fed to individual fish that were able to consume 400-500 nauplii in less than 5 min. At select times after feeding, fish were euthanized and the HAA or PBDE-47 content determined. The absorption of HAAs was quantitatively similar to previous studies in rodents: rapid absorption with peak body levels occurring within 1-2 h, then rapidly declining with elimination half-life of 0.3-3 h depending on HAA. PBDE-47 was more slowly absorbed with peak levels occurring by 18 h and very slowly eliminated with an elimination half-life of 281 h.

Acetates↗
PubMed2005

Tetracycline resistance of Australian Campylobacter jejuni and Campylobacter coli isolates.

OBJECTIVES: Tetracycline resistance in Campylobacter is encoded by the tet(O) gene and is usually associated with conjugative plasmids. Little was known about tetracycline resistance in Australian Campylobacter species, therefore we investigated this resistance in 41 Campylobacter jejuni and five Campylobacter coli strains from humans and healthy chickens. METHODS: Tetracycline MICs were determined for each isolate using an agar dilution method. The distribution and localization of tet(O) on plasmid and chromosomal DNA was determined by Southern-blot experiments. The ability to transfer resistance to recipient strains was examined through conjugation studies. Identity of transconjugants was confirmed by PCR and flaA-restriction fragment length polymorphism analysis. RESULTS: High-level tetracycline resistance was observed, ranging from 32 to >256 mg/L. Plasmids were detected in 74% of isolates with plasmids between 30 and 40 kb in size most frequently isolated. tet(O) was present in all tetracycline-resistant isolates. In the majority of strains under study the tet(O) gene was chromosomally encoded. Tetracycline resistance of six C. jejuni strains in which tet(O) was plasmid mediated was transferred by conjugation to a C. jejuni recipient strain. Transfer did not occur between tetracycline-resistant C. jejuni strains and a C. coli recipient. No difference in MICs, plasmid carriage and tet(O) localization was detected between human and chicken isolates. CONCLUSIONS: These data indicate that the tet(O) gene, previously reported in Campylobacter strains throughout the world, is present in Australian Campylobacter. This study will lead to a greater understanding of antibiotic resistance distribution in Campylobacter spp. in Australia.

Animals↗
PubMed2005

Implementing the water framework directive in Bulgaria: Integrated river basin management on the Black Sea coast.

EC member states and candidate countries are in the process of implementing the requirements of the EC Water Framework Directive 2000/60, which came into force on 22 December 2000. At the core of the Directive is an integrated approach for sustainable water management in river basin districts. The overall objective is to reach good water status for all waters by the year 2015. The challenges for countries implementing the Directive are substantial not least for the River Basin Management Authorities who will be the implementing unit at the regional level. The Black Sea River Basin Directorate in Varna is one of four Directorates established in Bulgaria in 2002 in accordance with the Bulgarian Water Act and is the regional operational unit under the Ministry of Environment and Water for the Black Sea Basin catchment area. The catchment area covers 20% of Bulgaria and 100% of the Bulgarian Black Sea coast. Current implementation activities in the Black Sea Basin Directorate and also at the national level are supported by the Danish EPA through its DANCEE programme in collaboration with the Ministry of Environment and Water. This paper highlights the main activities and outputs of the technical and institutional undertakings in the Black Sea Basin Directorate focusing on the preparation of the River Basin Overview by Dec. 2004.

Bulgaria↗
PubMed2003

Miniplate fixation for avulsion injuries of the flexor digitorum profundus insertion.

This article describes the use of a miniplate and cortical screws in the treatment of five cases of flexor digitorum profundus (FDP) tendon avulsion. One case was type II, three cases were type III and one case was type IV. Near normal joint congruity was restored together with bony union in all cases. Six months after surgery four cases had near normal range of motion at the distal interphalangeal joint compared with the contralateral uninjured finger. These four patients were to return to their previous activities without restriction by 3 months. One repair of a type III avulsion ruptured but the distal interphalangeal joint was pain free and stable and the patient declined further surgery. Miniplate fixation offers some advantages over existing methods of repair and adds to the range of techniques available for reattachment of the FDP tendon in these injuries.

Adolescent↗
PubMed1998

Impaired glycolysis and protein catabolism induced by acid in L6 rat muscle cells.

BACKGROUND: In skeletal muscle, metabolic acidosis stimulates protein degradation and oxidation of branched-chain amino acids. This could occur to compensate for impairment of glucose utilization induced by acid. METHODS: To test this hypothesis, glycolysis and protein degradation (release of [14C]-phenylalanine) were measured in L6 skeletal muscle cells cultured in Eagle's minimum essential medium at pH 7.1 or 7.5 for up to 3 days. RESULTS: No marked changes in total DNA or in cell viability were detected, nor was there any significant effect on intracellular pH or the water content of the cells (which is thought to be a key regulator of protein turnover, especially in liver). In spite of this, acid stimulated protein degradation, induced net protein loss from the cultures, inhibited glucose uptake and glycolysis (lactate output) and was associated with increased [1-14C]-leucine oxidation. Effects on protein degradation and glycolysis were gradual, reaching a maximum after 20-30 h. To investigate whether glycolytic flux itself can influence protein degradation, increased glycolysis was simulated by adding glucose (20 mmol L-1) or pyruvate (1 mmol L-1) to the medium. At pH 7.1, neither addition had any effect on protein degradation. CONCLUSION: Although acid-induced protein wasting is associated with impaired glycolysis, no obligatory coupling exists between glycolytic flux and protein degradation.

Acidosis↗
PubMed1996

Moral and social reasoning and perspective taking in later life: a longitudinal study.

In this study 27 older adults (ages 64-80) and 23 middle-aged adults (ages 35-54) were tested for moral stage, integrative complexity of social reasoning, and perspective-taking levels twice over a 4-year period. Moral reasoning stage levels did not change over time for either age group. Older adults, but not the middle-aged, showed a significant decline over time in level of moral perspective taking. Complexity of reasoning about several interpersonal social issues declined modestly in both age groups. More social-cognitive support, a higher education level, and better self-reported health were all found to be protective factors in forestalling declines in mature adults' sociocognitive reasoning, consistent with other research on cognitive measures in later life.

Adult↗
PubMed1989

Multiple plasma exchanges successfully maintain a young adult patient with Crigler-Najjar syndrome type I.

Plasmapheresis has been shown to reduce total and free bilirubin levels in acute exacerbations of Crigler-Najjar syndrome, type I (CNS-TI), but its effectiveness in long-term management has not been reported. An 18-year-old (yo) male with CNS-TI, who required prolonged daily high-intensity phototherapy to prevent cerebral nervous system symptoms, developed increasingly frequent bouts of confusion, nausea, and vomiting associated with free bilirubin concentrations (fbcs) greater than 10-15 nmol/L. Pending consideration of orthotopic liver transplantation, plasma exchange (approximately 3 liters per procedure) was begun in 12/84 using the IBM/COBE 2997 with 5% albumin as replacement fluid. Frequency of treatments was guided by twice weekly fbcs, with plasma exchange for fbc greater than 10-15 nmol/L. Pre-exchange and postexchange fbcs ranged from 27.5 to 11 nmol/L and 9.2 to 2 nmol/L, respectively. Seventy-two exchanges were performed over a 28 month period. Irreversible CNS damage did not occur, and the patient underwent successful liver transplantation in April of 1987, with complete correction of his metabolic disorder. He remains well 18 months following transplantation.

Adolescent↗
PubMed1987

Electrically evoked skin vasodilatation: a quantitative test of nociceptor function in man.

Direct stimulation of intact forearm skin affects adjacent microvascular blood flux. Pulses of current, known to activate C-fibres effectively, were applied over a period of 1-16 seconds at 2 Hz using transcutaneous stimulation. An increase of up to 50% was observed in skin microvascular blood flux. Increased blood flux correlated well with increasingly painful sensations. Some subjects responded to one or two pulses at 2 Hz, 0.5 ms in duration and 150 volts. A response onset latency of 4-15 s, lasting up to 5 minutes, was recorded. At higher frequencies (4-8 Hz) and more pulses (16-32) vasoconstriction was frequently observed before the usual flux increase. After administration of local anaesthesia (2% ligocaine) the resting skin blood flux increased, but electrical stimulation still produced vasodilatation. The local cutaneous flare response to electrical stimulation was abolished or greatly reduced by capsaicin pretreatment. Excitation of small intracutanous forearm nerve C-fibres produces increased microvascular blood flux which is dependent on local release of vasodilator substances. Thus the neurogenic flare (axon reflex) may have a physiological role in regulating skin blood flow, and nociceptor function may be measured by applying the aforementioned transcutaneous electrical stimulation.

Axons↗
PubMed1984

Cytochalasin B facilitates the inhibition of human polymorphonuclear leukocyte generation of superoxide by verapamil.

Several functions of the human neutrophil are dependent upon extracellular calcium for optimal activation. We studied the calcium dependency of human polymorphonuclear leukocyte (PMN) superoxide generation in response to opsonized zymosan particles and its modulation by the calcium channel antagonist verapamil. PMNs were isolated from anticoagulated blood after Ficoll-Hypaque density centrifugation. The isolated PMNs were incubated with opsonized zymosan particles. The superoxide anion generated was measured by a cytochrome C reduction assay. When PMNs were incubated with opsonized zymosan in a calcium-free buffer, there was 0.45 +/- 0.06 nmol of cytochrome C reduced per 1 X 10(6) PMN per minute. This increased to 0.76 +/- 0.12 nmol per 1 X 10(6) PMN per minute when 0.6 mmol/L Ca++ was present. Moreover, if the PMNs were incubated with cytochalasin B (5 micrograms/ml), the generation of superoxide anion was further enhanced. If the same experiments were conducted in the presence of verapamil, 100 mumol/L, superoxide generation was inhibited by 51.5% +/- 8.4%. For verapamil to inhibit superoxide generation, cytochalasin B was necessary. Our results suggest that verapamil-sensitive calcium channels may exist in human PMNs, and the demonstration of their presence is cytochalasin B-dependent.

Calcium↗
PubMed1979

A quantitative sutdy of vertebral displacement and angulation in the normal cervical spine under axial load.

Cervical traction of one-third the person's weight was applied for 3 minutes to normal subjects. The mean and standard deviation of displacement and rotation between adjacent cervical vertebra was calculated in the sagittal plane. The average separation between adjacent vertebra was 0.7 mm with a standard deviation of 0.5 mm. The average angular motion between adjacent vertebra was 0.9 degrees with a standard deviation of 2.4 degrees.

Adult↗
PubMedDate not supplied

Case management services for adolescent substance abusers: a program description.

A case management model for adolescent substance abusers whose problems are severe enough to warrant residential treatment is presented, based on the experience of a demonstration project. The five integral functions of case management (assessment, planning, linking, advocacy, and support) are described within the framework of each phase of an adolescent's treatment program (screening, residential treatment, and continuing care). Detailed descriptions of case management activities and the philosophy underlying case management are addressed. The integrated client tracking and program evaluation monitoring system developed for the case management project is described, and evaluation data are presented. Among the advantages case managers are able to offer to the entire treatment process include encouragement of family involvement in the youth's recovery; providing support; tracking substance abuse relapse episodes following treatment; connecting the youth with school, work, and community resources; and helping youth to fulfill legal obligations.

Adolescent↗
PubMedDate not supplied

Prospective study of transbronchial biopsies in the management of heart-lung and single lung transplant patients.

A prospective study of 219 bronchoscopies in 54 heart-lung and in 2 single lung transplant recipients was undertaken over a 12-month period by a single operator. For histologic study, an average of 17.3 transbronchial biopsy specimens (range, 6 to 56) were taken from three lobes (or from two lobes and lingula of one lung). A further two specimens were taken for culture. The average procedure time was 14.4 minutes (SE 0.31). An estimate of the probability of rejection being missed, depending on the number of specimens taken and based on the method of Gilman and Wang, suggests 18 biopsy specimens are required to have 95% confidence of diagnosing rejection. Sensitivity for diagnosing rejection by histologic study of transbronchial biopsy specimens was 94%, and specificity was 90%. The simple grading of severity of rejection that was used was related both to the number of specimens demonstrating rejection and to the severity of graft airway mucosal inflammation seen at bronchoscopy. The major complication encountered, on 27 occasions, was bleeding of more than 100 ml. On no occasion did bleeding result in any long-term complication. Extensive transbronchial biopsy is a simple, relatively safe, and quick procedure, with a high sensitivity and specificity for diagnosing rejection and lung infection.

Adolescent↗