Administration of angiotensin II in refractory septic shock.
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
V L Thomas
Publications and source records attributed to V L Thomas.
Estimation of aortic and pulmonary blood flow in a paediatric population using Doppler ultrasound: an in-vitro study.
The noninvasive measurement of blood flow using ultrasound has been attempted by numerous workers. In order to evaluate the technique of duplex scanning applied to the problem of noninvasive assessment of aortic and pulmonary blood flow in a paediatric population with ventricular septal defect, we attempted an in-vitro simulation of these flow conditions. The factors which have been considered in the design of the apparatus include the availability of a range of tube diameters, an aortic-"like" waveform, laminar flow, variable downstream peripheral resistance, a compliance factor and viscosity of the flow medium. The ultrasound probe beam characteristics, sample volume size and shape were also determined. From the results of the beam plots it was apparent that the region of sensitivity of the CW Doppler probes were inappropriate for the measurement of blood flow in neonates. In order to simulate physiological parameters in a paediatric population as closely as possible, five tubes of diameters ranging from 9-18 mm were used, in each tube a range of flow values from 0.8 L min-1 to 5 L min-1 were measured. The flow values were measured by both "bucket and stopwatch" and duplex scanner for both steady and pulsatile flow conditions. The results are presented as correlations between the direct and noninvasive pulsed Doppler assessment of flow measurement and are in the range 0.92-0.99 significant at p less than .001. A discussion of the reliability of flow measurements made using a conventional duplex scanner is given.
Aorta↗
Longitudinal evaluation of polymorphonuclear leukocyte chemiluminescence in premature infants.
A chemiluminescence (CL) microassay was used to evaluate polymorphonuclear leukocyte (PMN) function in premature newborn infants longitudinally during a 2-month period and in healthy adult control subjects. At postnatal ages of 12, 26, 40 and 54 days the infants' mean peak CL activity was significantly lower than that of the adults. Infants with one or more low CL responses were more severely ill than those with normal CL activity. The infants with low CL responses had longer hospital stays and a higher frequency of serious infections, as well as more days of level 3 care, antimicrobial therapy, supplemental oxygen, assisted ventilation, and total parenteral nutrition. The PMN CL activity before, during, and after episodes of serious infection did not differ. In addition, a high frequency of depressed CL activity was observed at the time of infection. Our findings are consistent with previous studies suggesting that defective PMN oxidative metabolic responses are more common in neonates undergoing stress. Our results further suggest that defective PMN function may persist for the first 2 months of life and during the course of serious infection. Enhancement of PMN host defense may be an important strategy in the management of neonatal sepsis.
Bacterial Infections↗
In vivo transfer of an R-plasmid in a urinary tract infection model.
Explore the source record for details and available documents.
Animals↗
Binding of staphylococci to mucus in vivo and in vitro.
The association of Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus saprophyticus with tissues of the upper respiratory tract were compared by using an in vivo ferret model. Ferrets were challenged intranasally with a 1-ml volume of radiolabeled staphylococci (3 mg [dry weight]), were allowed to clear the bacteria in vivo for 90 min, and were sacrificed. Tissues from the right nasal fossa were harvested and processed for radioassay or histology. Of the recoverable staphylococci, greater than or equal to 96% was associated with mucus gel overlaying mucosa of the turbinates. A quantitative radioassay was developed to study the binding of labeled staphylococci to immobilized crude ferret nasal mucin (FM) and bovine submaxillary gland mucin (BM). Binding showed saturation kinetics and was blocked specifically by BM but not by human Tamm-Horsfall glycoprotein nor orosomucoid. Binding to both FM and BM was significantly inhibited (P less than or equal to 0.01) when cocci were pretreated with trypsin but not when treated with beta-galactosidase or sodium metaperiodate (except for binding of S. saprophyticus to FM). These results suggest that mucin-binding receptors of the cocci may have protein components. The staphylococcus-binding receptors of both FM and BM appear to contain protein components, based on sensitivity to pretreatment with trypsin.
Amino Sugars↗
Antibody response to Staphylococcus aureus surface proteins in rabbits with persistent osteomyelitis after treatment with demineralized bone implants.
A rabbit model was used to study the effect of allogeneic demineralized bone powder (DBP) implants on the persistence of Staphylococcus aureus osteomyelitis. Thirty-one rabbits with chronic osteomyelitis of the tibia established by day 21, were started on systemic antibiotics followed by either no additional treatment or debridement plus either DBP (with or without supplemental antibiotics) or supplemental antibiotics only. On day 21, cultures showed a mean of 2 x 10(4) CFU/mg of debrided osseous material. By day 70, the treatment most effective in clearing infection was found in animals treated with supplemental antibiotics only (mean of 142 +/- 116 CFU/mg). In contrast, infection persisted at a 7- to 10-fold-higher level in animals receiving DBP with and without supplemental antibiotics; these results suggest that DBP contributed to persistence of infection. Longitudinal sera were tested again staphylococcal sonic extracts by immunoblot. Detection of numerous probe-positive bands indicated complex but remarkably similar antibody responses among infected animals. Antibodies attached directly to the cell surfaces of staphylococci as shown by immunogold and blocked the binding of organisms to HEp-2 and human fetal lung cells in a radioadherence assay. Antibodies could be absorbed out by intact organisms and were unreactive by immunoblot against antigens derived from cells pretreated with pronase, proteinase K, or lysostaphin. These results indicate that the major response was directed against staphylococcal cell surface proteins. Surprisingly, only one major band (molecular weight, approximately 12,000) was detected when a homologous in vivo antigen preparation was studied by immunoblot. Antibody reactive against this peptide did not appear to react with staphylococci grown in vitro.
Animals↗
Luminol-dependent chemiluminescence microassay for phagocytic function.
A luminol-dependent chemiluminescence (CL) microassay was developed to measure phagocytic function of peripheral blood leukocytes. Buffy coats, obtained by centrifugation of only 100 microliter of whole blood, provided an enriched population of polymorphonuclear leukocytes (PMNs). The total reaction mixture, consisting of leukocytes-luminol-inducer (opsonized zymosan), was 450 microliter. Peak CL activity was seen 5 min after addition of inducer at 37 degrees C with cells tested within 60 min after collection. Tests to determine precision and reproducibility of the microassay gave a coefficient of variation of 8.5% and 11%, respectively. There was no significant difference between the mean peak CL values for 20 healthy adult donors compared to 14 premature neonates, however, the newborns' CL activity declined more rapidly; CL activity was severely depressed in cells obtained from a patient with chronic granulomatous disease. Results suggest that this microassay provides a simple, rapid, and reliable test of phagocytic function in cases where the amount of blood available for testing is limited.
Humans↗
The effect of fentanyl on propofol requirements for day case anaesthesia.
Fifty women of ASA grade 1 or 2 scheduled to undergo minor gynaecological procedures were allocated randomly to two groups. Group A received fentanyl 100 micrograms intravenously before induction; group B received no sedative or analgesic drugs. Anaesthesia was induced with propofol intravenously and maintained using 67% nitrous oxide in oxygen with incremental doses of propofol. Induction time and dose were significantly less and mean arterial pressure decreased significantly lower in Group A. These differences were, however, small and the ranges of values were large. The incidence of side effects and subjective assessment of quality of anaesthesia were similar in both groups. Fentanyl did not confer any practical advantage when used with propofol in the techniques described above.
Adjuvants, Anesthesia↗
Distribution of type 1 and P pili on uropathogenic Escherichia coli O6.
The distribution of type 1 and P pili on individual cells of an O6 uropathogenic Escherichia coli strain, 6260, was determined immunologically with pilus-specific monoclonal antibodies by indirect immunofluorescence and immunogold electron microscopy. Variations in pilus expression under different culture conditions were monitored with an indirect immunofluorescence assay; 63% of piliated cells expressed type 1 pili when grown on agar at 37 degrees C versus 14 to 38% when grown in broth at 37 degrees C. In contrast, generally fewer cells with P pili (18 to 44%) were detected on agar than when grown in broth (up to 86%). Both type 1 and P pili were absent from cells cultured at 20 degrees C. Immunogold and immunofluorescence double labeling techniques with monoclonal antibodies 11-2 and 91-1 were used to study subpopulations of cells with type 1 and P pili; 39 to 41% of the piliated cells demonstrated only type 1 pili, and 12 to 16% of the cells showed only P pili. The immunogold method proved more sensitive than the immunofluorescence technique for detecting subpopulations expressing both pili types simultaneously, 19 versus 7%. We observed variations between type 1 and P pili, both in expression on individual cells and in the distribution of subpopulations of cells.
Adult↗
Relationships between human blood groups, bacterial pathogens, and urinary tract infections.
Blood groups of 137 patients with acute pyelonephritis and chronic upper tract infection, cystitis, and asymptomatic bacteriuria were compared with those of a normal uninfected control population. In addition, the identified uropathogens were categorized according to the patient's blood group. There was a significant association between the diagnosis of chronic upper tract infection and blood group B as compared with controls (p = less than 0.05, chi 2). Analysis of the bacterial isolates showed that more patients with blood group B had infections with Pseudomonas sp., Klebsiella pneumoniae, and Proteus sp. than was expected; and fewer patients with blood group A had infections with Pseudomonas than predicted (p = less than 0.05, chi 2). There was an increased number of patients in blood group AB with infections caused by Escherichia coli and Klebsiella pneumoniae. These results suggest that an individual's blood group may be a significant factor in the host-response to bacterial invasion and influence the development of infection with certain gram-negative bacilli.
ABO Blood-Group System↗
Single breath induction of anaesthesia, using a vital capacity breath of halothane, nitrous oxide and oxygen.
Inhalational induction of anaesthesia, using a single vital capacity breath of 4% halothane in 66% nitrous oxide and 33% oxygen was evaluated in 100 unpremedicated outpatients. The technique was found to be acceptable to most (91%) of the patients studied, with a mean (SD) induction time (measured from beginning of inspiration to loss of 'eyelash reflex') of 83(21) seconds. Relative cardiovascular stability was a notable finding of the technique, with a slight decrease in the mean arterial pressure of only 10%. Anaesthetic induction time was unaffected by age, weight or smoking habits. The technique of single breath induction is therefore proposed as a safe and acceptable alternative to intravenous induction in co-operative adult patients.
Adolescent↗
Utilization of anion-exchange chromatography and monoclonal antibodies to characterize multiple pilus types on a uropathogenic Escherichia coli O6 isolate.
Multiple pilus types from a uropathogenic strain of Escherichia coli O6, strain 6260, were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), high-pressure liquid chromatography, binding assays, and erythrocyte adsorption. In addition, monoclonal antibodies were raised against purified pili of E. coli 6260 and used for immunological characterization. SDS-PAGE analysis of the purified pili showed at least three different subunits with molecular weights of 15,700, 17,800, and 19,300. SDS-PAGE analysis of four protein peaks from anion-exchange chromatography of intact pili showed polypeptides with molecular weights of 19,300 (fraction 1), 15,700 (fraction 2), and 17,800 and 15,700 (both fractions 3 and 4). Erythrocyte adsorption of the whole-pilus preparation removed the 17,800-molecular-weight subunit (17.8K subunit) and reduced the 15.7K subunit. Pili from an isogenic hemagglutination-negative variant of E. coli 6260, showing only the 15.7K and 19.3K subunits by SDS-PAGE, lacked the 17.8K subunit of fractions 3 and 4 present in the parent high-pressure liquid chromatography profile. Our data suggest that two of the pilus subunits, the 15.7K and 17.8K subunits, mediate mannose-resistant agglutination of human erythrocytes. Pili in fractions 1 and 2 from the parent strain bound specifically to mannose residues, while pili in fraction 4 bound to P-coated horse erythrocytes; no receptor specificity was identified for pili in fraction 3. Immunological analysis by the immunoblot technique showed that monoclonal antibody 11-2 reacted with the 19.3K subunit, monoclonal antibodies 34-3 and 73-3 reacted with the 15.7K subunit, and monoclonal antibodies 81-1, 82-1, and 91-1 reacted with polymers of subunits retained in the stacking gel. Intact pili precipitated by any of the six monoclonal antibodies showed two polypeptides by SDS-PAGE: 15.7K and 19.3K polypeptides for monoclonal antibody 11-2, and 15.7K and 17.8K polypeptides for monoclonal antibodies 34-3, 73-3, 81-1, 82-1, and 91-1. The cross-reactivity of the monoclonal antibodies with purified pili from other E. coli strains was determined by enzyme-linked immunosorbent assay. Monoclonal antibody 11-2 showed no significant cross-reactivity with heterogeneous pili. In contrast, the other monoclonal antibodies showed equivalent or greater reactivity with P pili from heterologous strains as compared with reactivity with E. coli 6260 pili.(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
Characterization of clinical strains of Staphylococcus aureus associated with pneumonia.
A total of 5 Staphylococcus aureus strains from patients with postinfluenzal staphylococcal pneumonia, 7 from burn patients with staphylococcal pneumonia, and 21 from the nasopharynx of carriers were phenotypically characterized. All or most strains produced coagulase, clumping factor, DNase, thermostable DNase, protease, gelatinase, lipase, and pigment; the strains were low to moderate producers of extracellular protein A, fibrinolysin, and alpha-hemolysin. All strains were sensitive to mercury, half were sensitive to arsenate and cadmium, and 67 to 92% were resistant to penicillin. Differences between strains were not statistically significant. Cell surface hydrophobicity was determined by measuring percent adsorption to hexadecane. Hydrophobicity of postinfluenzal staphylococcal pneumonia strains was significantly lower than that of pneumonia strains from burn patients and carriers (P less than 0.005). Immunoblot experiments with sera immune to one clinical test strain allowed the separation of all strains into three groups based on probe-positive reactions with primarily four staphylococcal polypeptides (154,200, 130,000, 77,100, and 64,400 molecular weight). The difference in distribution of clinical and carrier strains was highly significant (P = 0.007).
Adolescent↗
Fimbrial phase variation and DNA rearrangements in uropathogenic isolates of Escherichia coli.
Having previously shown that the oscillating on-off expression (phase variation) of type 1 fimbriae in Escherichia coli is regulated genetically by an invertible element of DNA, we wished to determine whether E. coli isolates recovered from infected humans behaved in similar fashion. We examined four different clinical isolates that expressed type 1 fimbriae, P fimbriae, or both. Using, in Southern blot analysis, a DNA probe from the type 1 fimbrial switch, that hybridized to one DNA band from phase-on bacteria and to two DNA bands from phase-off bacteria, we found that the three clinical isolates expressing type 1 fimbriae contained the same invertible switch previously seen in the K-12 isolate. Employing a similar approach to characterize the on-off expression of P fimbriae, we used a DNA probe containing the known transcriptional signals for P fimbriae. Although we detected DNA rearrangement in the two strains expressing P fimbriae, unlike the case for type 1 fimbriae, the rearrangement did not correlate with the on-off state of the P fimbriae. Rather, the DNA rearrangement correlated with the environmental conditions of growth of the bacteria from which the DNA was isolated. These results confirm the notion that P fimbriae expression and type 1 fimbriae expression are controlled differently.
DNA, Bacterial↗
Mannose-resistant hemagglutination and P receptor recognition of uropathogenic Escherichia coli isolated from adult patients.
Adhesions of 211 strains of uropathogenic Escherichia coli and 19 strains of normal fecal E. coli were characterized by patterns of agglutination with human erythrocytes, Saccharomyces cerevisiae, and horse erythrocytes coated with the P blood-group receptor (P). Mannose-resistant (MR) hemagglutination was significantly associated with P agglutination (P less than .001). E. coli expressing MR and/or P (MR/P) agglutinins concurrently with mannose-sensitive (MS) agglutinins predominated in all clinical categories. The highest percentage of E. coli demonstrating MR/P agglutinins, in the absence of MS agglutinins, was recovered from patients with acute pyelonephritis (35%) compared with percentages of patients with chronic pyelonephritis (13%), asymptomatic bacteriuria (16%), cystitis (11%), and normal fecal control E. coli (11%). Sixty-nine percent of E. coli isolates causing acute pyelonephritis agglutinated P-coated horse erythrocytes compared with only 11% of the fecal isolates. Strains expressing MR/P agglutinins (in the absence of MS agglutinins) isolated from patients with acute pyelonephritis, chronic pyelonephritis, and asymptomatic bacteriuria were significantly associated with the presence of antibody-coated bacteria in patients' urine sediments (P less than .010), an observation indicative of an immune response associated with bacterial invasion of host tissues.
Adhesins, Escherichia coli↗
Antibody to kidney antigen in the urine of patients with urinary tract infections.
One hundred six urine specimens from 26 patients with acute and chronic pyelonephritis and cystitis were tested by radioimmunoassay to determine (1) whether antibody to normal human kidney antigen was present and (2) whether the presence or absence of this antibody correlated quantitatively with antibody to the patient's own infecting organism. Of the 106 urine specimens tested, 55 (52%) contained elevated antibody to human kidney antigen. For 80 (75%) of 106 urine specimens there was a correlation between the results of quantitative assays for antibody levels to kidney antigen and to the bacterial antigen. Indirect fluorescent antibody studies of thin sections of normal human kidneys and a patient's urine containing elevated levels of antibody to kidney antigen and to bacterial antigen demonstrated diffuse renal localization. Results indicate the occurrence of antibody to kidney antigen, particularly in urine specimens from patients with chronic pyelonephritis and from urine specimens containing elevated levels of antibody to bacterial antigen.
Antibodies↗
Antibody-coated bacteria in urinary tract infections.
Explore the source record for details and available documents.
Antibody-Coated Bacteria Test, Urinary↗