Bidirectional vena cava filter placement.
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Acute Disease↗
Biomedical subjects
A Kerr
Publications and source records attributed to A Kerr.
Comparison of antimicrobial susceptibility methods for detection of penicillin-resistant Streptococcus pneumoniae.
We sought to determine if commercially available susceptibility tests were accurate in detecting penicillin resistance and relative resistance in Streptococcus pneumoniae. We compared the reference MIC method with oxacillin disk screening and three commercial tests, E-test (AB Biodisk), JustOne (Radiometer America), and MicroScan Pos MIC Panel Type 6 (Baxter Diagnostics), with 80 selected clinical isolates. Thirty-three additional isolates were tested by the reference method and the E-test to further validate the latter method. Oxacillin screening was effective in detecting all penicillin-resistant and relatively resistant strains of S. pneumoniae. The MicroScan method was not effective in detecting penicillin resistance or relative resistance. The JustOne system classified only 6 (35%) of 17 resistant strains correctly, with 11 resistant strains classified as relatively resistant. The E-test correctly classified 30 (83%) of 36 resistant isolates, with 6 resistant isolates interpreted as relatively resistant. For determining penicillin MICs for S. pneumoniae, the E-test was the most accurate of the commercial systems that we studied.
Humans↗
The association between tuberous sclerosis and insulinoma.
We describe a patient with tuberous sclerosis and an insulinoma. The neurologic abnormalities typically present in patients with tuberous sclerosis may, in rare cases, be manifestations of hypoglycemia. We discussed a possible association between tuberous sclerosis and multiple endocrine neoplasia type I.
Adult↗
Transcatheter hepatocyte transplantation: preclinical studies of anatomic consequences in the portal vascular bed.
RATIONALE AND OBJECTIVES: Intrasplenic transplantation deposits hepatocytes in host hepatic sinusoids with amelioration of chronic liver failure and genetic deficiency states. Because portal resistance can be altered by intrasinusoidal transplanted cells, we examined whether hepatocyte recipients would develop deleterious portal hypertension or portosystemic collaterals. METHODS: Syngeneic hepatocytes in suspension were transplanted into recipient rats by transcatheter injection into the splenic parenchyma. Subjects included recipients of 2 x 10(7) hepatocytes representing approximately 3% of the host hepatic mass, recipients of 7.5 x 10(7) hepatocytes representing approximately 12.5% of the host hepatic mass, normal control rats, and positive control rats with portal hypertension induced by partial portal vein constriction. Portal pressures were recorded with a sensitive transducer, portosystemic collaterals were demonstrated with direct splenoportography, and survival of transplanted cells was determined with an endogenous dipeptidyl peptidase IV reporter gene. RESULTS: In normal rats, the portal pressure was 6.25 +/- 1.9 mm Hg with no portosystemic collaterals. By contrast, portal pressures were significantly increased in portal vein-constricted rats, 20.7 +/- 3.9 mm Hg (P < 0.001), with extensive portosystemic collaterals. In hepatocyte recipients, portal hypertension observed during transcatheter cell injection but proved transient. When animals were examined up to 16 weeks after hepatocyte transplantation, portal pressures were in the normal range (after 2 x 10(7) cells, 7.5 x 2.6 mm Hg; after 7.5 x 10(7) cells, 9.5 +/- 4.2 mm Hg, P = not significant). No portosystemic collaterals developed in hepatocyte recipients at various times up to 8 months after transplantation. Transplanted hepatocytes expressing the reporter gene were present in recipients with assimilation in host hepatic cords. CONCLUSION: Despite injection of a massive number of cells, transcatheter hepatocyte transplantation was devoid of any significant portal vascular alterations or toxicity in recipients. These findings are consistent with assimilation of transplanted hepatocytes into host hepatic cords and will facilitate therapeutic applications in metabolic diseases or acute liver failure.
Animals↗
Platelet bacterial contamination and the use of a chemiluminescence-linked universal bacterial ribosomal RNA gene probe.
BACKGROUND: Currently, the maximum outdate for platelets is 5 days, because of the increasing chance of bacterial growth over time. Various methods for rapid detection of bacterial contamination of blood components have been described, with mixed results and no general acceptance. A recently described, molecular biologic approach for the detection of bacterial contamination involves a chemiluminescence-linked universal DNA bacterial probe to a highly conserved bacterial region of ribosomal RNA (rRNA). STUDY DESIGN AND METHODS: A multicenter trial of a chemiluminescence-linked universal bacterial rRNA probe for the detection of bacterial contamination in platelet concentrates is described. At each of five sites, platelet concentrates (no older than 1 day from date of phlebotomy) were inoculated in triplicate with isolates of four bacterial species (Pseudomonas aeruginosa, Bacillus cereus, Staphylococcus epidermidis, and Staphylococcus aureus) to a final concentration of 10 to 50 colony-forming units (CFUs) per mL and in triplicate to a final concentration of 1000 CFUs per mL. At one site, an additional 6 platelet concentrates were inoculated with sterile saline to serve as controls. Inoculated units were then subjected periodically to quantitative cultures and probe analyses. A total of 126 platelet concentrates were studied over a period of 7 days (120 inoculated with bacteria and 6 with sterile saline). RESULTS: This assay was, in some cases, able to detect S. aureus bacterial contamination in the range of 100 to 1000 CFUs per mL; the majority of samples (B. cereus, P. aeruginosa, S. aureus, and S. epidermidis) with contamination exceeding 10(4) CFUs per mL; and all samples with contamination of 2.1 x 10(5) CFUs per mL or greater. Increasing the sample size from the recommended 0.4 mL to 1.0 mL resulted in an unacceptable loss of specificity (83.3%). CONCLUSION: The routine use of this assay would be expected to result in a decreased risk of septic platelet transfusion reactions and could lead to a lengthening of the current 5 day storage period for platelets. Further, the pooling of random-donor platelet concentrates before storage instead of immediately before transfusion may be possible if this rRNA probe is employed to detect bacteria in the pool.
Bacillus cereus↗
Agrobacterium conjugation and gene regulation by N-acyl-L-homoserine lactones.
Conjugal opines secreted by crown gall tumours induce strains of Agrobacterium tumefaciens that are donors of Ti plasmids to produce a diffusible conjugation factor. This enhances the conjugal transfer efficiency of the Ti plasmid in other strains of A. tumefaciens. This factor behaves as a secondary messenger, transmitting the environmental information to tra genes. Here we report the use of spectrometry to show that this factor is identical to synthetic N-(beta-oxo-octan-1-oyl)-L-homoserine lactone and confirm that the synthetic compound is biologically active. N-(Hexan-1-oyl)-L-homoserine lactone has also been detected. A closely related molecule, N-(beta-oxo-hexan-1-oyl)-L-homoserine lactone, autoinduces bioluminescence in the distantly related bacterium, Vibrio fischeri. N-Acyl-homoserine lactones thus seem to be conserved molecules in which the length and nature of the lipophilic acyl chain determines the biological function to be regulated. Mutants that do not produce the factor fail to conjugate unless supplied with it in the induction medium (our unpublished data). These data indicate that the conjugation factor is an autoinducer and a key signal molecule in the conjugation system of A. tumefaciens. It is, to our knowledge, the first example of a second messenger molecule in a bacterial conjugation system.
Agrobacterium tumefaciens↗
Clinical features of individuals with cystic fibrosis in New Zealand.
AIMS: To determine the status of cystic fibrosis patients, their mode of diagnosis and source of medical care in New Zealand. METHODS: A database was established in 1988 to record clinical information on individuals with cystic fibrosis in New Zealand. Three hundred and two cystic fibrosis patients were identified and clinical information on 248 obtained. RESULTS: Thirty five per cent of patients at diagnosis had gastrointestinal and pulmonary and 33% had gastrointestinal symptoms alone. Ninety three infants were diagnosed after a positive screening test and confirmatory sweat test. The mean age at diagnosis overall was 1.8 years, while 61% of children were diagnosed before one year of age. 74.2% of patients were said to be pancreatic insufficient, 4% pancreatic sufficient and in 22% the results were unavailable or unknown. Medical care was provided by 28 sources comprising paediatricians, physicians or combined clinics. One cystic fibrosis clinic cared for more than 40 patients. Sixty-one per cent of cystic fibrosis subjects were colonised with Staphylococcus aureus at some time, and 44% were reported to be colonised with Pseudomonas aeruginosa. CONCLUSIONS: Common clinical features of cystic fibrosis have been characterised for New Zealand patients. It is unknown to what extent the clinical features of the disease and source of medical care in New Zealand are responsible for previously reported survival for the condition but it is planned to examine serial measurements of growth, nutrition, pulmonary function and survival and it is hoped that these measurements will be the subject of a further report.
Adolescent↗
The use of a chemiluminescence-linked universal bacterial ribosomal RNA gene probe and blood gas analysis for the rapid detection of bacterial contamination in white cell-reduced and nonreduced platelets.
Because of the rising incidence of bacterial growth and septic platelet transfusions in aging units, platelet storage is currently limited in the United States to 5 days. This approved shelf life of platelets might be altered if methods were devised to rapidly detect infected units and/or to decrease the incidence of bacterially contaminated platelets. An investigation was conducted on the effect of a prototype blood collection system with an in-line filter for the production of white cell-reduced platelet-rich plasma on the growth of bacteria in platelets prepared from whole blood that had been inoculated with Staphylococcus epidermidis. Additional studies were conducted with a chemiluminescence-linked ribosomal RNA (rRNA) gene probe and with blood gas analysis to identify possible methods for the rapid detection of bacterial contamination. All units were followed for 9 days of storage. The filtration of the platelet-rich plasma resulted in an approximate 2 log10 reduction in white cells with an average loss of 6.7 percent of platelets. Filtration did not appear to alter bacterial growth. In all platelet units that supported growth, pO2 dropped to negligible values and pCO2 rose relative to culture-negative units. The changes were most sensitive and specific beyond 5 days of storage. The universal bacterial rRNA probe assay was able to detect S. epidermidis in concentrations as low as 1 x 10(3) colony-forming units per mL in some cases and reliably detected all units contaminated at a concentration of 1 x 10(4) colony-forming units per mL.(ABSTRACT TRUNCATED AT 250 WORDS)
Blood Gas Analysis↗
Acquired traumatic pulmonary arteriovenous fistula: case report.
Post-traumatic pulmonary arteriovenous fistula, a rare entity, was treated in a 35-year-old HIV-positive man by transcatheter embolization. When seen 4 months later, the patient had florid Pneumocystis carinii pneumonia. Generally, pulmonary angiography demonstrates such fistulae when they are not visible on chest roentgenograms. This diagnosis should be considered in patients with penetrating chest trauma when suggestive clinical or radiologic signs are present.
Adult↗
Emotional and behavioural aspects of Rett syndrome.
A survey of 107 families of children with Rett syndrome was conducted to further define the behavioural phenotype. There was a high prevalence of behavioural and emotional problems, including episodes of anxiety (76 per cent), low mood (70 per cent) and self-injurious behaviour (49 per cent). Although there was no significant difference across the age-ranges studied, there was a tendency towards a reduction in these problems with increasing age, suggesting that the behavioural phenotype in Rett syndrome varies with age. Epilepsy occurred in over half the children, but there was no clear association with behavioural and emotional problems. A number of families had established strategies for coping with their child's anxiety and mood changes.
Activities of Daily Living↗
Rapid purification of Ti plasmids from Agrobacterium by ethidium bromide treatment and phenol extraction.
An efficient method is described for the purification of Ti plasmid DNA from Agrobacterium. The procedure is based on the relative binding capacity of ethidium bromide to supercoiled plasmid DNA and linear DNA and on the high solubility of ethidium bromide in phenol. Following treatment with ethidium bromide, more than 87% of linear chromosomal DNA and most of the RNA was present in the phenol phase, while 91% of Ti plasmid DNA was recovered from the aqueous phase. The Ti plasmid DNA was sufficiently pure for restriction endonuclease analysis and cloning. The procedure is simple, fast and provides eight times higher yield than the standard isopycnic ultracentrifugation method.
Agrobacterium tumefaciens↗
X-ray diffraction analysis of urinary calculi in Durban.
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Humans↗
Subclavian artery to innominate vein fistula after insertion of a hemodialysis catheter.
Insertion of hemodialysis catheters for temporary use is now preferentially performed by percutaneous infraclavicular subclavian vein catheterization. This method involves passage of a stiff dilator and a peel-away sheath over a guide wire, and is usually carried out without fluoroscopy. For the most part this has proved to be a valuable and safe approach. However, a small incidence of major complications occurs, which needs to be emphasized. Sixteen cases of arteriovenous fistulas between the subclavian artery or its branches and the subclavian vein have been reported so far in the literature. To date only one case of subclavian artery to innominate vein fistula has been reported. We report the second case with this complication and suggest possible preventive measures.
Adult↗
A diffusible compound can enhance conjugal transfer of the Ti plasmid in Agrobacterium tumefaciens.
Several octopine strains of Agrobacterium tumefaciens were tested for Ti plasmid (pTi) transfer after induction by 400 micrograms of octopine per ml for 24 h. The strains could be divided into two groups, transfer efficient (Trae) and transfer inefficient (Traie); the respective rates of transfer were 0.77 x 10(-2) to 1.14 x 10(-2) and 0.33 x 10(-6) to 9.8 x 10(-6) plasmid transconjugant per donor cell. Transfer efficiencies of Traie strains were greatly increased when the time of induction was 72 h. A diffusible conjugation factor (CF) that can enhance conjugal transfer of pTi in A. tumefaciens was discovered when both Trae and Traie donor strains were induced in the same plate. The evidence indicates that CF is a key factor affecting transfer efficiency of pTi but is not sufficient by itself to induce transfer. Trac mutants can produce CF constitutively, and Trae strains can produce it after induction by low octopine concentrations. The transfer efficiency of Traie strains was greatly increased by adding CF to the induction medium. The thermosensitive strain B6S, which normally cannot conjugate at temperatures above 30 degrees C, could transfer pTi efficiently at 32 and 34 degrees C in the presence of CF. Production of CF is dependent on the presence of pTi but appears to be common for different opine strains; it was first detected in octopine strains, but nopaline strains also produced the same or a similar compound. CF is very biologically active, affecting donor but not recipient bacterial cells, but CF does not promote aggregation. Data suggest that CF might be an activator or derepressor in the conjugation system of A. tumefaciens. CF is a dialyzable small molecule and is resistant to DNase, RNase, protease, and heating to 100 degrees C for 10 min, but autoclaving (121 degrees C for 15 min) and alkaline treatment removed all activity.
Arginine↗
Non-attendance at a psychiatric day hospital new patient clinic.
People who do not attend for treatment present problems in the efficient running of any service. This is particularly the case with new patients referred to a psychiatric clinic where an hour may be set aside for the initial assessment. High non-attendance rates cause administrative problems and loss of valuable time. The referring doctor may be left with his patient unassessed, the patient may miss valuable treatment or advice, and an incorrect assessment of the true prevalence of some disorders may be made.
Hospitals, Psychiatric↗
Percutaneous catheter drainage for acute empyema. Improved cure rate using CAT scan, fluoroscopy, and pigtail drainage catheters.
Percutaneously inserted pigtail nephrostomy catheters were used to treat empyemas in 12 patients. Thoracic computed tomographic (CT) scan and fluoroscopy were used to localize precisely and place the catheters into loculated collections of fluid. Percutaneous catheter drainage (PCD) of empyema was successful in seven of seven patients (100%) in whom standard tube thoracostomy (STT) had initially failed and in three of five patients (60%) who had PCD as the initial drainage procedure. Overall, PCD was successful in treating empyema in ten of 12 patients (83%). The procedure was well tolerated and there were no complications. PCD is a safe and effective method for drainage of loculated empyemas as the initial procedure or after STT has failed.
Acute Disease↗
A case of fatal hemorrhage caused by intestinal histoplasmosis.
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Adult↗
The pTiC58 tzs gene promotes high-efficiency root induction by agropine strain 1855 of Agrobacterium rhizogenes.
Root induction on flax (Linum usitatissimum L.) cotyledon explants by Agrobacterium rhizogenes strain 1855 is markedly increased by co-inoculation with disarmed A. tumefaciens strain LBA 4404 containing a plasmid carrying the tzs gene of pTiC58. Most of the roots (estimated to be more than 90%) were transformed. This effect is most likely due to the secretion of trans-zeatin by A. tumefaciens stimulating the division of plant cells making them more receptive to transformation by A. rhizogenes, although other explanations are possible. This observation supports the idea that the tzs gene, although not essential for transformation, may promote transformation. An obvious application for genetic engineering experiments involving transformation by A. rhizogenes, is to include a vir-induced tzs gene in the transformation system to help maximize transformation efficiency.
DNA, Bacterial↗