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Biomedical subjects

G Reid

Publications and source records attributed to G Reid.

At least 199 records · Page 11Linked to original sources
PubMed1985

Competitive exclusion of uropathogens from human uroepithelial cells by Lactobacillus whole cells and cell wall fragments.

Previous studies have shown that indigenous bacteria isolated from cervical, vaginal, and urethral surfaces of healthy women are able to adhere to human uroepithelial cells in vitro. Furthermore, these organisms were found to block the adherence of uropathogenic bacteria to uroepithelial cells from women with and without a history of urinary tract infections. In the present study, complete or partial inhibition of the adherence of gram-negative uropathogens was achieved by preincubating the uroepithelial cells with bacterial cell wall fragments isolated from a Lactobacillus strain. Competitive exclusion was most effective with whole viable cells and less effective with cell wall fragments obtained by sonication, extraction with sodium dodecyl sulfate, and treatment with sodium dodecyl sulfate and acid. Analysis of the Lactobacillus cell wall preparations suggested that lipoteichoic acid was responsible for the adherence of the Lactobacillus cells to uroepithelial cells but that steric hindrance was the major factor in preventing the adherence of uropathogens. This conclusion was also supported by blockage studies with reconstituted lipoteichoic acid-peptidoglycan, which was more effective at blocking adherence than lipoteichoic acid or peptidoglycan alone. The results suggest that the normal flora of the urinary tract may be used to protect against the attachment of uropathogens to the surfaces of uroepithelial cells. The long-term implications of these findings may lead to alternative methods for the management and prevention of recurrent urinary tract infections in females.

Adult↗
PubMed1985

Prevention of urinary tract infection in rats with an indigenous Lactobacillus casei strain.

Our previous studies have shown that indigenous bacteria are able to block the in vitro attachment of uropathogenic bacteria to human uroepithelial cells. In the present study, we applied the concept of competitive exclusion to an animal model. A chronic urinary tract infection was established in female rats with bacteria incorporated into agar beads injected periurethrally into the urinary bladder via a no. 3 French ureteral catheter. Five strains of uropathogenic organisms were used in the first set of experiments, and their colonization of the bladder and kidneys of the animals was confirmed up to 2 months after injection. The uropathogens stimulated an immune response, detected by serum antibodies against the uropathogens, and an inflammatory response noted in sections of the kidneys stained with hematoxylin and eosin. Using this animal model, we established the persistent adherence of bacteria in the urinary tract without the need for creation of obstruction or implantation of a foreign body. In a second set of experiments, an isolate of Lactobacillus casei GR1 taken from the urethra of a healthy woman was incorporated into agar beads, instilled within the rat bladders on day 1, and then swabbed twice weekly for 21 days onto the introitus before challenge with uropathogens instilled into the urinary bladder. In 21 of 25 animals, no uropathogenic bacteria were recovered from the bladder and kidney tissues up to 60 days after challenge, and no immune response was detected. Our results show that L. casei prevented onset of urinary tract infection in 84% of the animals tested. The lactobacilli appeared to exclude the uropathogens from colonizing the urinary tract, within the first 48 hours after challenge, and the net effect was a complete eradication of bacteria from the uroepithelium. It is hoped that the demonstration of a protective role for indigenous bacteria in preventing urinary tract infection in an animal model will lead to the application of this technology to prevent recurrent urinary tract infection in female patients.

Adult↗
PubMed1985

A fluorescent antibody staining technique to detect bacterial adherence to urinary tract epithelial cells.

A fluorescent antibody technique has been devised to assess specifically the adherence of Escherichia coli in vitro to uroepithelial cells from healthy women and bacterial adherence in vivo to cells from women with symptomatic urinary tract infection. Similar values can be obtained using methylene blue as the bacterial stain, but this depends on the experience of the observer. The results indicate that E. coli adherence to uroepithelial cells is a factor in the infection process. We suggest that uroepithelial cells from patients with symptoms of a urinary tract infection whose urine has a low bacterial count (less than 10(3) cells/ml) could be examined for the presence of adherent uropathogens, which may be indicative of an infection. Although the fluorescent staining technique possibly would be expensive, the results would be specific and reliable. Other diagnostic and research applications suggest themselves as in studies of bacterial colonization of mucosal tissues or plastic catheters, where conventional light microscopy and radiolabelling methods are not effective.

Adhesiveness↗
PubMed1984

In vivo attachment of E coli to human epithelial cells.

There was a high incidence of a mannose sensitive adhesin and a mannose resistant and eluting adhesin among 111 Escherichia coli urinary isolates and 23 faecal isolates. Attachment of E coli to human uroepithelial and buccal cells was significantly higher for strains possessing a mannose resistant adhesin after growth on agar. Strains possessing a mannose sensitive adhesin after single or multiple subculutres in broth did not attach in large numbers and the adherence was unaffected by the presence of D-mannose. The mannose resistant adhesin was more often detected in strains with O serotypes commonly found in urinary tract infections, was produced at 37C but not at 18C and was destroyed or weakened by exposure to heat and formaldehyde treatment. Electron microscopy confirmed fimbrial presence on 67% of strains producing a mannose resistant adhesin, but non-fimbriated strains attached equally well to uroepithelial cells.

Adhesins, Escherichia coli↗
PubMed1984

Bacterial adherence in the human ileal conduit: a morphological and bacteriological study.

A retrospective study of 50 patients with urinary diversion was undertaken to determine the incidence of bacteriuria and upper tract infection. Eighty-four per cent of these patients developed bacteriuria caused by a variety of pathogenic organisms and 14 per cent had clinical evidence of pyelonephritis. A phased morphological and bacteriological study was then carried out in a further 17 patients with ileal conduits. Electron microscopy examination of cup biopsy specimens from superficial and deep segments of the conduit showed virtually no bacteria adhering to the columnar cells of the conduit, although Gram positive cocci were seen adhering to the keratinized cells from the muco-cutaneous junction. However, the conduit mucus was heavily colonized, initially with yeasts, then sequentially with microcolonies of Gram-positive and Gram-negative bacteria, up to 16 years after urinary diversion had been performed. Bacteriological examination of conduit and stomal mucus and urine specimens of these 17 patients confirmed the presence of large numbers of uropathogens . Of 23 conduit isolates, 9 possessed hemagglutinins, 18 of 18 attached to uroepithelial cells in vitro and 6 of 6 attached to ureteral transitional cells in vitro, indicating their adhesive and pathogenic capabilities.

Bacteriuria↗
PubMed1984

Adherence of cervical, vaginal and distal urethral normal microbial flora to human uroepithelial cells and the inhibition of adherence of gram-negative uropathogens by competitive exclusion.

The adherence of the normal flora to human uroepithelial cells was examined using scanning and transmission electron microscopy and an in vitro adhesion assay. The normal flora were isolated from human cervical, vaginal and distal urethral surfaces. Human uroepithelial cells were obtained from healthy females (controls) and from female patients with recurrent urinary tract infection. The results indicate that: 1) there was no significant difference between the mean adherence of the normal flora to the uroepithelial cells from controls or patients, but there were quantitative differences between different bacterial species of the normal flora attaching to uroepithelial cells; 2) bacterial species isolated from the distal urethral and vaginal surfaces attached in larger numbers to uroepithelial cells from controls than from patients at day 10 of the menstrual cycle (peak value of adherence); 3) the adherence patterns of the cervical and vaginal microbial flora were bicyclic and appeared to be related to the human menstrual cycle; 4) complete or partial inhibition of adherence of several Gram-negative uropathogens was achieved by preincubating the uroepithelial cells with several bacterial species of the normal flora. Results from this study suggest that the normal flora of the urinary tract may play an important protective role against attachment of uropathogens to the surfaces of uroepithelial cells, and that the blocking capacity of these organisms may vary over the menstrual cycle.

Cervix Uteri↗
PubMed1984

Microbial colonization of human ileal conduits.

Morphological and microbiological techniques were used to locate and identify the microorganisms that colonized the human ileal conduits in 17 different patients from 5 days after surgery up to as many as 16 years of service as a urine conduit. The ecological sequence of this colonization assumes some practical importance because the ascending growth of pathogenic organisms in this essentially open, unvalved urinary tract diversion system leads to the development of life-threatening pyelonephritis. Extensive examination of the microvillus surfaces of the ilea of five accident victims by both transmission and scanning electron microscopy showed that these tissue surfaces were not colonized by bacteria, even in the absence of prophylactic antibiotic therapy, and that these surfaces were not occupied by adherent microorganisms after several years of service as a urine conduit, even when the skin surface stoma and the conduit contents were heavily colonized by bacteria and yeasts. During the initial period (10 days) of postoperative antibiotic therapy, the mucus and urine within the conduit were largely colonized by yeasts. A mixed population of yeasts and gram-positive cocci subsequently developed in the conduit itself, and gram-positive cocci were seen to be avidly adherent to epidermal cells at the stoma. As antibiotic protection was gradually withdrawn, gram-negative organisms became a part of the mixed microbial flora of the conduit contents, and some of the potentially pathogenic organisms of this group (e.g., Escherichia spp., Proteus spp., Pseudomonas spp., etc.) were isolated from patients with pyelonephritis that appeared to come from the ileal conduit.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteria↗
PubMed1983

In vitro attachment of Escherichia coli to human uroepithelial cells: variation in receptivity during the menstrual cycle and pregnancy.

An in vitro system was used for assay of the attachment of Escherichia coli to viable uroepithelial cells harvested from the urine of premenopausal women. A 15% level of variation from the mean attachment value was noted within given cell samples. Uroepithelial target cells with large numbers of adherent bacteria were found. The receptivity of uroepithelial cells to the attachment of certain strains of E coli varied over the menstrual cycle and during pregnancy. This finding may suggest that adult women are more susceptible to urinary tract infection at particular times during their reproductive period. Double-staining techniques were used for the detection of bacterial attachment to mucopolysaccharide-coated and non-mucopolysaccharide-coated uroepithelial cells. The level of attachment of one strain of E coli was higher when cells were mucus coated, while the attachment of a second strain was unaffected by the presence of a mucus coat. The results suggest the existence of at least two different mechanisms whereby E coli attaches to uroepithelial cells.

Adhesins, Escherichia coli↗
PubMed1982

The use of double staining techniques for investigating bacterial attachment to mucopolysaccharide-coated epithelial cells.

Double staining techniques were devised to study Escherichia coli attachment to mucopolysaccharide-coated urinary tract epithelial cells. In addition, vital stains were used to distinguish between viable and nonviable epithelial cells. Alcian blue was used to confirm the presence of glycosaminoglycans and periodic acid Schiff was used to distinguish a further group of polysaccharides, proteoglycans, neutral mucosubstances and glycolipids. The staining methods enabled investigations to be carried out concerning the possible importance of mucopolysaccharides in the attachment of bacteria to mucosal surfaces. Staining techniques were also used to investigate whether the presence of a mucopolysaccharide coat is related to epithelial cell viability. The combinations of vital and mucopolysaccharide stains were found to give reproducible results when cell preparations were evaluated by three individuals. Both in vivo and in vitro certain populations of epithelial cells have been found with a large number of bacteria preferentially attached. The double staining techniques described here may help to reveal the nature of these target cells.

Adhesiveness↗
PubMed1982

Systemic lupus erythematosus during penicillamine therapy for rheumatoid arthritis.

Six patients with rheumatoid arthritis developed a syndrome resembling lupus erythematosus while being treated with penicillamine. All patients had previous mucocutaneous reactions to chrysotherapy. Manifestations included pleurisy in five of six patients, rashes in three, nephritis in two, and neurologic disturbances in two; lupus erythematosus cells were found in five patients, antinuclear antibodies in all six, antideoxyribonucleic acid in three, positive Coombs' test results for three patients, and low C4 complement in five of the six. Symptoms were slow to resolve after penicillamine treatment was discontinued, and four of the patients needed corticosteroid therapy. A higher frequency than expected of HLA A 11 in three patients and B 15 in five patients was seen.

Adult↗
PubMed1982

Characterization of transformed cells and tumors by proton nuclear magnetic resonance spectroscopy.

Cultured acute lymphoblastic leukemic cells give a well-resolved proton nuclear magnetic resonance spectrum characteristic of isolated plasma membranes. We demonstrate that the signals, in the spectrum of whole cells, arise predominantly from the plasma membrane and that cells transformed by pokeweed mitogen have membranes which are significantly less rigid than are normal human peripheral blood lymphocytes. Normal thymus, malignant thymus, and a leukemic T-cell line have been compared by proton nuclear magnetic resonance spin echo experiments, and the normal thymus was found to differ. Cells transformed by the Epstein-Barr virus can also be characterized and shown to differ from the leukemically transformed cells by spin echo experiments. Since no probe molecule was required to obtain these results, this is the first definitive evidence that the structure and fluidity of the plasma membranes change as a result of transformation of lymphocytes. Proton nuclear magnetic resonance spectroscopy can now be used to compare the effect of different mitogens on T- and B-lymphocytes as well as to monitor the effects of drugs, metals, etc., on the plasma membrane of transformed lymphocytes.

B-Lymphocytes↗
PubMed1982

Serum digoxin levels in neonates whose weights are less than 1,500 grams.

Digoxin was given to 29 infants in congestive heart failure and weighing less than 1,500 gm. All the infants were considered to have an isolated patent ductus arteriosus and were recovering from the respiratory distress syndrome. Forty-eight serum digoxin levels were measured after 4 or more days on twice daily parenteral maintenance therapy and a significant correlation obtained between the dose and resultant serum level (P less than .001). A total parenteral maintenance dose of 5 micrograms/kg produced a serum level of 2.4 ng/ml (+/- 1.2 ng). This is a much lower dose regime than in frequently recommended and underscores the need for caution in digitalizing small premature infants.

Digoxin↗
PubMed1981

Sports' medicine.

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New Zealand↗
PubMed1980

The effects of memory strategy instruction in the short-term motor memory of the mentally retarded.

The present study investigated the effectiveness of teaching mnemonic strategies aimed at overcoming difficulties of mentally retarded students in retaining the motor short-term memory information of a preselected movement. The memory strategy employed was a combination of the "feel" of the movement and the spatial location of the hand relative to the body. The design of the study was a 2 x 2 (Instructional Treatment x Retention Condition) factorial. The instructional treatment factor included teaching the subjects a memory strategy versus no memory-strategy instruction. The retention condition factor included immediate recall and a 15-sec retention interval. There were five trials per subject. The data were interpreted as supporting the effectiveness of the memory-strategy instruction.

Journal Article↗
PubMed1980

Hypogammaglobulinaemia associated with abnormalities of both B and T lymphocytes in patients with chronic lymphatic leukaemia.

The underlying basis for hypogammaglobulinaemia in patients with chronic lymphatic leukaemia (CLL) was investigated by measurement if immunoglobulin produced in vitro in cultures of pokeweek mitogen-stimulated B and T lymphocytes. B and T cells were separated by sheep red blood cell rosette techniques and, by culture of these cells from CLL patients in various combinations with B or T cells from normal subjects, it was possible to measure independently the function of B lymphocytes and the helper or suppressor function of T lymphocytes. By these methods it was found that the B lymphocytes of six of eight patients failed to produce immunoglobulins in vitro. B lymphocytes from two patients appeared to produce immunoglobulins in vitro. T lymphocytes from five of the eight patients had low or undetectable helper T cell function and in six patients their T lymphocytes had excessive suppressor activity in comparison to T lymphocyte populations from normal subjects. Whether the primary abnormality in the CLL T cell populations was a deficiency of helper T cells or excess of suppressor T cells was uncertain from these studies. These results suggest that immunoglobulin production by B lymphocytes from most patients with CLL was abnormal but also that T cells from CLL patients may be abnormal in respect to their role in immunoglobulin production at an early stage of the disease. These findings may assist in understanding the pathogenesis of this disease and lead to new approaches in treatment.

Agammaglobulinemia↗
PubMed1980

Overt and covert rehearsal in short-term motor memory of mentally retarded and nonretarded persons.

Overt rehearsal and the presence of covert rehearsal in short-term motor memory of a retarded group and two nonretarded groups of students (n = 100 in each group) was investigated. Subjects were randomly assigned to five retention conditions: immediate recall, a 20-second unfilled interval, a 20-second interval filled with interpolated mental activity, a 20-second interval of overt rehearsal, and a 20-second interval filled with simultaneous overt rehearsal and interpolated mental activity. Results indicated that retarded persons did not engage in spontaneous covert rehearsal of motor information while nonretarded persons did. The short-term motor memory of retarded and nonretarded groups was not different when covert rehearsal was not possible and during overt rehearsal. In general, however, overt rehearsal did not facilitate motor memory.

Adolescent↗