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Biomedical subjects

G Reid

Publications and source records attributed to G Reid.

At least 145 records · Page 8Linked to original sources
PubMed1992

A recombinant feline immunodeficiency virus envelope fusion protein stimulates peripheral blood lymphocytes from naive cats to proliferate in vitro.

A region of feline immunodeficiency virus (FIV)/Glasgow-8 external envelope glycoprotein (env) incorporating the third and fourth variable regions (V3/V4) was cloned, inserted into the pGEX vector and expressed in Escherichia coli to yield milligram quantities of the recombinant polypeptide as a fusion protein with glutathione S-transferase. The fusion protein V3/V4GST was used in lymphocyte proliferation assays, where it consistently caused peripheral blood lymphocytes from naive cats to proliferate in a dose-dependent manner. Other FIV fusion proteins produced under identical conditions (V5GST and p24GST) and glutathione S-transferase alone did not cause proliferation in this system. The monoclonal antibody vpg15, which has been shown to block infection of susceptible cells in vitro, did not decrease the response to V3/V4GST. Human peripheral blood lymphocytes did not proliferate in response to V3/V4GST.

Amino Acid Sequence↗
PubMed1992

Enhancement after feline immunodeficiency virus vaccination.

Cats were vaccinated with one of the three preparations: purified feline immunodeficiency virus (FIV) incorporated into immune stimulating complexes (ISCOMs), recombinant FIV p24 ISCOMs, or a fixed, inactivated cell vaccine in quil A. Cats inoculated with the FIV ISCOMs or the recombinant p24 ISCOMs developed high titres of antibodies against the core protein p24 but had no detectable antibodies against the env protein gp120 or virus neutralising antibodies. In contrast, all of the cats inoculated with the fixed, inactivated cell vaccine developed anti-env antibodies and four of five had detectable levels of neutralising antibody. However, none of the vaccinated cats were protected from infection after intraperitoneal challenge with 20 infectious units of FIV. Indeed there appeared to be enhancement of infection after vaccination as the vaccinated cats become viraemic sooner than the unvaccinated controls, and 100% of the vaccinated cats became viraemic compared with 78% of the controls. The mechanism responsible for this enhancement remains unknown.

Adjuvants, Immunologic↗
PubMed1992

Antibiotic resistance of urinary pathogens isolated from patients attending the Toronto Hospital between 1986 and 1990.

A study was carried out on 1523 urinary isolates obtained at The Toronto Hospital, Canada's largest tertiary care establishment, over three 1-month periods in 1986, 1987 and 1990. Escherichia coli was the most frequently isolated organism, with Enterococcus spp. the second most common isolate in 1986 and 1987, and Streptococcus spp. in 1990. Pseudomonas aeruginosa isolates were found to be resistant to many of the antimicrobial agents tested. Resistance patterns were found to commonly prescribed ampicillin, co-trimoxazole and, to some extent, the new fluoroquinolones, ciprofloxacin and norfloxacin. These results are relevant to the treatment and management of urinary tract infections in patients attending a tertiary care hospital.

Cross Infection↗
PubMed1992

Incorporation of soluble antigens into ISCOMs: HIV gp120 ISCOMs induce virus neutralizing antibodies.

Through a process of covalent attachment of palmitic acid, we have incorporated recombinant gp120 of HIV strain IIIB into ISCOMs. Rabbits immunized with ISCOMs incorporating 10 micrograms gp120 produced high levels of gp120-specific antibody, comparable to the response to ten times as much antigen in complete Freund's adjuvant. The ISCOM-induced antisera showed virus neutralizing activity against the homologous strain, but failed to neutralize two heterologous strains of HIV-1. The antisera recognized non-conformationally determined epitopes on gp120, and antibody binding to gp120 was affected by glycosylation of the viral glycoprotein.

AIDS Vaccines↗
PubMed1992

Soluble proteins incorporate into ISCOMs after covalent attachment of fatty acid.

The immune stimulating complex (ISCOM) is a potent adjuvant which has the ability to induce both humoral and cellular immune reactions to protein antigens when they are physically associated with the ISCOM structure. However, in general only proteins with an exposed hydrophobic domain can associate with ISCOMs. As many soluble proteins are available as candidate subunit antigens there is a requirement for a method which promotes efficient incorporation of soluble protein into ISCOMs. Here it is demonstrated that following covalent attachment of palmitic acid, two soluble proteins, cytochrome C and ovalbumin, quantitatively incorporate into ISCOMs. ISCOMs containing ovalbumin prepared in this way have been shown to be highly immunogenic, generating humoral, delayed-type hypersensitivity and class I restricted T-cell immune responses following both parenteral and oral administration. The technique of incorporating soluble proteins into ISCOMs by covalent attachment of fatty acid should be generally applicable and extends the use of the ISCOM as an adjuvant.

Antigens↗
PubMed1992

A surgical model for normotensive chronic renal failure in the growing piglet.

Studying the effects of chronic uremia in children has been hindered by the lack of a suitable large mammalian animal model with normotensive renal failure. We performed nephrectomy with simultaneous contralateral partial nephrectomy using a stapling device and absorbable staples in 22 domestic piglets. Up to 93% of the total renal mass could be excised by this method. A chronic uremic state was reproducibly developed and correlated with the percentage of renal mass excised. There were no associated postoperative complications with the stapled partial nephrectomy. Pigs with moderate renal failure had a significant decrease in growth compared to those with mild renal failure, which represents the successful development of a normotensive large mammalian animal model that could be used to study the effects of chronic renal failure and hyperfiltration during a state of rapid growth. In addition, this study confirms the successful use of a stapling device to perform partial nephrectomy.

Animals↗
PubMed1992

Microbial adhesion and biofilm formation on ureteral stents in vitro and in vivo.

Thirty ureteral stents, inserted for 5 to 128 days following extracorporeal shock wave lithotripsy, were examined for the presence of bacterial biofilms. Of these, 90% had adherent pathogens (44% mixed organisms) on the stents, 45% of which were present in low numbers (10(1)-10(2) per 1 cm3 section) and 55% were in small and large microcolony biofilms (> 2 x 10(2)-10(7)). The organisms were recovered from the stents even though urine culture was only positive in 27% of patients. Of the organisms isolated, 77% were Gram positive cocci, 15% Gram negative rods and 8% Candida. No blockage of the stents occurred. All of the patients had received antimicrobial therapy post-insertion, and in 15 cases biofilms were found while on treatment. None of the patients received therapy for urinary tract infections while the stent remained in place. In vitro experiments demonstrated the ability of Escherichia coli, Proteus mirabilis, Staphylococcus epidermidis and Enterococcus faecalis uropathogens to adhere and form biofilms on ureteral stents within 24 hours. Clearly, bacterial biofilms do occur on ureteral stents and urinary culture may not detect their presence. The high recovery rate of Gram positive organisms may indicate a preferential adhesion to the biomaterial surface. The findings also indicate that unlike biofilm formation on many other prosthetic implants, colonization with Gram positive organisms on ureteral stents does not necessarily coincide with the development symptomatic infection.

Adolescent↗
PubMed1992

Bacterial biofilm formation in the urinary bladder of spinal cord injured patients.

Ten spinal cord injured patients aged 8 to 55 years (mean 32) were followed for up to 2 months after admission to a rehabilitation setting from an acute care hospital. Urinary fluid and bladder epithelial cells were collected weekly by intermittent catheterization and examined for bacterial colonization. Six patients had no history of urinary tract infection upon admission, likely due to the antimicrobial coverage given during acute care. All the patients subsequently became colonized with uropathogens at some time during the study period. Bacterial biofilms were found in 73% of the samples (73% Gram negative organisms, 27% Gram positive), with mean pathogenic adhesion counts of 29 organisms per bladder cell. In 16% of cases, bladder biofilms were found when urine culture was negative. Bacterial biofilms were also evident during antimicrobial therapy in 10 of 12 samples tested and urine cultures showed breakthrough infections in 50% of cases. Two asymptomatic patients were colonized with Klebsiella pneumoniae and Pseudomonas aeruginosa and were dismissed without requiring therapy. Clearly, bacterial biofilms can exist on bladder epithelia, without being detected in urine samples and without giving rise to symptoms. The extent to which they occur and damage the host remains to be determined, as does the answer to the question, should these patients be treated?

Adult↗
PubMed1992

Hydrogen peroxide production by Lactobacillus species: correlation with susceptibility to the spermicidal compound nonoxynol-9.

Facultative anaerobic lactobacilli were recovered from the vaginas of 96.8% of 63 nonpregnant, healthy, premenopausal women. The predominant species were Lactobacillus jensenii, Lactobacillus acidophilus, and Lactobacillus casei. Of the women, 74.6% had hydrogen peroxide-producing lactobacilli, 22.2% had non-hydrogen peroxide-producing lactobacilli, and 3.2% had no lactobacilli. None of the 68 isolates had catalase activity. Some 68.2% of the isolates were inhibited by concentrations of less than or equal to 1% (wt/vol) of nonoxynol-9 (bactericidal for 73.3% of isolates, bacteriostatic for 26.7%). The remaining 31.8% could grow in all concentrations to 25% (wt/vol) of nonoxynol-9. All of the lactobacilli that were sensitive to nonoxynol-9 produced hydrogen peroxide whereas only 3 of 21 resistant strains were hydrogen peroxide producers. A significant correlation (P less than .001, chi 2 test) was found between hydrogen peroxide production and sensitivity to nonoxynol-9. It is suggested that the vaginal flora of spermicide users could be depleted of hydrogen peroxide-producing lactobacilli, possibly increasing susceptibility to urogenital infection.

Adult↗
PubMed1992

Comparison of contact angles and adhesion to hexadecane of urogenital, dairy, and poultry lactobacilli: effect of serial culture passages.

The aim of this study was to examine the hydrophobicities of 23 urogenital, dairy, poultry, and American Type Culture Collection isolates of lactobacilli and to determine the effect on hydrophobicity of serially passaging the strains in liquid medium. To this end, strains were grown after isolation and identification and then serially passaged up to 20 times. Hydrophobicity was assessed through contact angle measurements on lawns of cells by using water, formamide, methylene iodide, 1-bromonaphthalene, and hexadecane as wetting agents and through measurement of their partitioning in a hexadecane-water system. The hydrophobicities of these strains varied widely, with Lactobacillus casei strains being predominantly hydrophilic and L. acidophilus strains being mostly hydrophobic. For some isolates, serial passaging was accompanied by a clear loss of hydrophobic surface properties, whereas for other strains, cultures became heterogeneous in that some cells had already lost their hydrophobic surface properties while others were still hydrophobic. Adhesion of this collection of lactobacilli to hexadecane droplets in microbial adhesion to hexadecane (MATH) tests was driven by their aversion to water rather than by their affinity for hexadecane, as concluded from the fact that hexadecane contact angles were zero for all strains. Furthermore, adhesion of the lactobacilli to hexadecane in MATH tests occurred only when the water contact angle on the cells was above 60 degrees.

Adult↗
PubMed1992

Quantitative measures of sympathetic skin response in diabetes: relation to sudomotor and neurological function.

The sympathetic skin response (SSR) at the foot to a deep inspiration was measured in 68 randomly selected diabetic patients and 46 age matched normal subjects and compared with other quantitative measures of neurological and sudomotor function. SSR was obtained in all but three diabetic patients. The upper limit of normal for the onset latency was 2202 ms and the lower limit for the amplitude of the first wave 92 microV. Ten diabetic patients had measurable but prolonged latencies, and 11 had measurable but low amplitudes. There were no significant associations between latency, height, and age, but in insulin dependent patients there was a significant diminution of response amplitude with increasing duration of diabetes. Latency was weakly associated with Marstock thermal thresholds, respiratory RR variation, and common peroneal nerve conduction velocity. SSR amplitude was associated with the density of pilocarpine activatable sweatspots in the same region of the foot. Patients with abnormal latencies were significantly older and had reduced thermal sensation than those with normal latencies. Median coefficients of variation for repeat testing in diabetic patients were 9% for latency and 13% for amplitude. The test is objective and reproducible, but latency measurements reflect conduction in a long multineuronal pathway and are not purely a measure of peripheral C fibre function; amplitude measurements reflect the density of spontaneously activable sweat glands and are therefore a valid measure of peripheral sympathetic activity, though they depend more on temperature than do latencies (mean change over the range 32-34 degrees C; 8.5% degrees C for amplitude, -2.5%/degrees C for latency).

Adult↗
PubMed1992

Reliability and validity of three fitness tests for adults with mental handicaps.

To examine the reliability and validity of cardiovascular fitness tests, 10 untrained controls and 18 adults with mental handicaps (experimental group) completed five trials on each of four exercise protocols. VO2 max results (M +/- SD) averaged across trials were as follows: Maximal treadmill test, 27.2 +/- 6.2 for the experimental group (E) and 45.5 +/- 8.1 for the control group (C); Maximal shuttle run test, 19.7 +/- 3.4 (E) and 42.1 +/- 6.2 (C); Submax step test, 33.0 +/- 7.6 (E) and 44.5 +/- 7.6 (C); and Submax cycle ergometer test, 36.4 +/- 13.1 (E) and 42.0 +/- 7.1 (C). The four modes had similar VO2 max values across trials with intraclass correlations ranging from r = .90 to .97. To examine validity, the predictive tests were compared with the treadmill VO2 max test. Both the step and shuttle run tests correlated significantly with the treadmill test. The duration of the shuttle run test was unrelated to the exercise intensity. The stepping test is recommended over both the maximum shuttle run test and the submaximum cycling test when measuring the aerobic fitness of adults with mental handicaps.

Adult↗
PubMed1992

Myb expression is higher in malignant human colonic carcinoma and premalignant adenomatous polyps than in normal mucosa.

Expression of the protooncogene c-Myb protein was assessed in normal mucosa and in tumor samples resected from six patients. We found that the tumor samples always expressed higher levels of full length Myb protein than the normal tissue. This contrasts with the situation in c-myb-associated hemopoietic malignancies of the mouse and chicken, in which Myb proteins are generally amino or carboxyl truncated. Tissues from five patients with colonic adenomatous polyps were also examined and found to express levels of Myb that were, in general, intermediate between those found in normal tissues and tumors. Of particular interest is that the more dysplastic polyps displayed higher Myb levels. In one patient with carcinoma and multiple colonic polyps, some polyps had intermediate levels of Myb, whereas one polyp with carcinoma in situ expressed tumor-like levels of Myb. To directly test the hypothesis that Myb expression may be important in determining the rate of colonic cell proliferation, we examined three colonic carcinoma cell lines and one polyp cell line. We found that the cell lines with the most rapid doubling times exhibited the highest Myb levels. In addition, we show that antisense myb oligonucleotides retard the proliferation of one of these colonic cell lines which expresses the highest level of Myb.

Base Sequence↗
PubMed1991

Ability of uropathogens to bind to Tamm Horsfall protein-coated renal tubular cells.

Epithelial cells were isolated from a healthy human kidney and found to be of normal, renal tubular origin. The cells were maintained in tissue culture and found to secrete Tamm Horsfall protein (THP). Three strains of uropathogenic Escherichia coli, and one each of Proteus mirabilis and Pseudomonas aeruginosa were found to adhere to the THP-coated tubular cells. Extraneous THP bound to all the organisms except P fimbriated E. coli, and caused a reduction in the adhesion of type 1 fimbriated E. coli and P. mirabilis to the renal cells. However, irrespective of reduced adhesion in three of five strains tested, there was adequate evidence to indicate that THP does not competitively exclude all uropathogenic adhesion. On the contrary, its presence on renal cells may act to mediate bacterial colonization.

Bacterial Adhesion↗
PubMed1991

Immunodiagnosis of feline immunodeficiency virus infection using recombinant viral p17 and p24.

The coding sequences of p17 and p24 of the Glasgow-8 strain of feline immunodeficiency virus (FIV) were amplified using the polymerase chain reaction and cloned into plasmid vectors. The predicted amino-acid sequences of FIV/Glasgow-8 p17 and p24 were compared with those of the Petaluma and PPR isolates of FIV. As seen with other retroviruses, these gag gene products are highly conserved, indicating that the protein products would be suitable antigens to detect anti-FIV antibodies in an immunoassay. Both p17 and p24 were stably expressed in Escherichia coli as fusion proteins with glutathione S transferase. A pure preparation of each fusion protein was obtained from induced bacterial lysates by affinity chromatography using glutathione-agarose beads. These recombinant proteins were used in an enzyme-linked immunosorbent assay to detect antibodies directed against FIV p17 and p24 in cat sera. This assay allows the identification of seropositive cats following infection with FIV and has greater sensitivity and specificity than a currently available immunodiagnostic test.

Amino Acid Sequence↗
PubMed1991

Assessment of basal and stimulated sweating in diabetes using a direct-reading computerized sudorometer.

Abnormalities of eccrine sweating are thought to be common in diabetes. We describe a ventilated-capsule sudorometer for the continuous measurement of basal and stimulated sweat secretion. It is sensitive (detecting as little as 200 ng water vapour), precise, and stable. Since it measures dewpoint rather than relative humidity, it can be calibrated to read sweat volumes directly and independently of ambient temperature and humidity. Preliminary studies using this technique show that basal skin water loss is significantly diminished in patients with established diabetic neuropathy (0.91 +/- 0.18 g (+/- SD) cm-2 h-1) compared with normal subjects (1.21 +/- 0.39 g cm-2 h-1; p = 0.04) and non-neuropathic diabetic subjects (1.32 +/- 0.48 g cm-2 h-1; p = 0.04), and that local sweating induced by iontophoresis of 10 g l-1 acetylcholine is significantly reduced in diabetic subjects up to 5 min of recording (0.95 +/- 0.43 vs 1.26 +/- 0.40 mg; p = 0.02). In neuropathic subjects both low- and high-amplitude responses are seen, the latter probably representing denervation supersensitivity. Further studies with sensitive sudorometry should enable the mechanisms of these abnormal responses to be established.

Acetylcholine↗