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Biomedical subjects

C McQueen

Publications and source records attributed to C McQueen.

13 recordsLinked to original sources
PubMed2001

Treatment of gastrointestinal infections.

Studies aimed at improving treatment strategies for patients with acute diarrhea have included the clinical testing of modifications to the standard oral rehydration solution. A malabsorbed carbohydrate has been found to improve resuscitation, probably through the recruitment of colonic absorptive capacity. A reduced osmolarity solution is safe in adults and as effective as the standard solution. For non-nursing infants, increasing the frequency of feeding with reduced volume results in comparable total caloric intake and diminishes the risk of prolonged diarrhea. Increasing resistance of important enteric pathogens to inexpensive and newer antibiotics continues to be a concern. Reports from Asia of decreased Salmonella typhi resistance to chloramphenicol, attributed to restricted antibiotic usage, may indicate a reversal of the usual trend. A strategy to block the action of shiga toxins in the gut through the use of recombinant bacteria has shown promise in a mouse model. A small but well-designed study supported the use of either norfloxacin or amoxicillin-clavulanic acid in the treatment of small bowel overgrowth syndrome. Studies exploring passive immunity strategies for the treatment of Escherichia coli, Cryptosporidium, and Candida infections have reported variable levels of success.

Journal Article↗
PubMed1999

Retrieval and analysis of particulate debris after saphenous vein graft intervention.

OBJECTIVES: This study was designed to evaluate the composition and quantity of particulate debris resulting from vein graft intervention. BACKGROUND: Distal embolization and "no reflow" are frequent and important complications resulting from angioplasty of diseased saphenous vein grafts. Little is known about the composition and quantity of embolic particulate debris associated with vein graft intervention, and no intervention has been shown to protect against its clinical consequences. METHODS: A catheter system, designed to contain, retrieve and protect against distal embolization of this material, was evaluated during 27 percutaneous interventional saphenous vein graft procedures. Clinical, angiographic and pathologic analyses were performed. RESULTS: The duration of distal graft occlusion required to allow intervention and subsequent debris removal was 150 +/- 54 s, decreasing as experience was gained. Thrombolysis in Myocardial Infarction trial (TIMI) flow grade increased from 2.6 +/- 0.8 to 3.0 +/- 0.0. Creatine kinase (CK) rose above normal in three patients (11.1%) exceeding 3x normal in one (3.7%) resulting in the diagnosis of non-Q-myocardial infarction. Particulate material was identified following 21 of 23 procedures suitable for analysis. Particle size was 204 +/- 57 microm in the major axis and 83 +/- 22 microm in the minor axis. Particles consisted predominantly of soft acellular atheromatous material, such as that typically found under a fibrous cap. Semiquantitative analysis suggested that the quantity of particulate material was less following stenting than following balloon dilation. CONCLUSIONS: Particulate matter is commonly present following routine angioplasty and stenting of saphenous vein grafts. Containment, retrieval and analysis of this particulate debris are all feasible. Comparison to prior clinical experience is limited by small sample size. However, to the extent that these particles may contribute to distal embolization, no-reflow and infarction, such a system may contribute to the reduction of complications following vein graft intervention.

Aged↗
PubMed1997

A prospective study of changes in negative mood states of women undergoing surgical hysterectomy: the relationship to cognitive predisposition and familial support.

Levels of anxiety and depression were documented by questionnaire response from a sample of 89 women who were to undergo surgical hysterectomy 3 weeks later. Fifty-four per cent (n = 48) of the sample reported anxiety and 26% (n = 23) reported depression at clinical levels during the preoperative period, with an additional number (n = 16 anxiety; n = 19 depression) at borderline status. Despite an overall significant postoperative reduction of negative mood states, clinical levels of anxiety were found in a substantial minority of women both 2 (24%) and 6 months (31%) after surgery. Levels of depression at these times were respectively 13% and 11% of the sample which provided postoperative information. These data confirm previous reports of high levels of negative mood states in patients referred for surgical hysterectomy. However, analyses of individual profiles of change confirm that there was a beneficial outcome for the large majority of the women, with 83% of those with clinical levels of anxiety showing improved status. Regression analyses indicated that postoperative outcomes with respect to negative affect could be predicted from preoperative status, and the data provide some support for the hypothesis that for a minority of women, negative mood states co-presented with gynecological symptoms may not be attenuated by surgery. Both dispositional resilience and familial cohesiveness were entered as significant variables in regression models examining postoperative status, although they provided only a limited increase to the postoperative variance prediction from measure of preoperative levels of affect. Preoperative mood status was found to be inversely related to an intrapersonal dimension of 'dispositional resilience' and to 'family cohesiveness'. It is suggested that measurement of preoperative mood status to family cohesiveness and dispositional resilience may provide useful adjunctive measures in attempts to identify women at risk of reporting an unsatisfactory surgical outcome.

Adult↗
PubMed1995

Assessment of attenuated Salmonella typhimurium strains designed as potential carriers of foreign antigens for mucosal localization and immuno-genicity in a rabbit model.

Neither wild type nor attenuated S. typhimurium strains induced diarrheal illness in rabbits. All strains localized to the Peyer's patch at higher concentrations than in lumenal contents or adjacent ileum. Wild type S. typhimurium C5 induced a typhoid-like illness in rabbits with severe weight loss, bacteremia, persistent splenic colonization, and serum IgG response. Both attenuated strains were disseminated to spleen (day 3) but produced minimal systemic illness. They induced biliary IgA responses greater than the wild type (day 7), but minimal serum IgG responses. Both mutants of S. typhimurium are suitable for further development as live enteric vaccines to carry foreign antigens since they localize to Peyer's patch after oral inoculation, induce biliary antibody, and produce minimal systemic disease. The attenuated strains tested are systemically disseminated. It remains to be determined whether dissemination (determined by a large virulence plasmid) is necessary for the desired mucosal immune response or acceptable for an oral vaccine strain.

Administration, Oral↗
PubMed1991

Treatment of travelers' diarrhea: ciprofloxacin plus loperamide compared with ciprofloxacin alone. A placebo-controlled, randomized trial.

OBJECTIVE: To compare the safety and efficacy of loperamide used in combination with ciprofloxacin or ciprofloxacin alone for the treatment of travelers' diarrhea. DESIGN: Double-blind, placebo-controlled, randomized clinical trial. SETTING: United States Army hospital in Egypt. PARTICIPANTS: United States military personnel with travelers' diarrhea (n = 104) during a military exercise in November 1989. Persons who were noncompliant, had bloody diarrhea, or had received antidiarrheal medications before entry into the study were excluded. INTERVENTIONS: All participants with travelers' diarrhea were treated with ciprofloxacin, 500 mg twice daily for 3 days. Fifty of these patients were randomly assigned to receive loperamide, a 4-mg first dose and 2 mg for every loose stool (as much as 16 mg/d), and 54 were randomly assigned to receive placebo. MEASUREMENTS: Enterotoxigenic Escherichia coli was isolated from 57% of patients; Shigella and Salmonella, seen in 4% and 2% of patients, respectively, were not common. MAIN RESULTS: After 24 hours, the symptoms of 82% of patients in the ciprofloxacin and loperamide group compared with 67% in the ciprofloxacin and placebo group had improved or fully recovered (odds ratio, 2.3; 95% CI, 0.8 to 6.3; P = 0.08). After 48 hours, the symptoms of 90% of both groups had improved or fully recovered. The mean number of stools for those receiving loperamide was not much lower than those who did not receive loperamide after 24 hours (1.9 +/- 0.2 [SE] compared with 2.6 +/- 0.2) or 48 hours (3.1 +/- 0.3 compared with 4.0 +/- 0.3) of treatment (P = 0.19). CONCLUSIONS: In a region where enterotoxigenic E. coli was the predominant cause of travelers' diarrhea, loperamide combined with ciprofloxacin was not better than treatment with ciprofloxacin alone. Loperamide appeared to have some benefit in the first 24 hours of treatment in patients infected with enterotoxigenic E. coli. Both regimens were safe.

Ciprofloxacin↗
PubMed1990

Interactions of methemoglobin and green hemoprotein in chemiluminescent gels.

Peroxidation of luminol (5-amino-2,3-dihydrophthalazine-1,4-dione) catalyzed by human green hemoprotein (GHP) and bovine methemoglobin (MetHb) in gels composed of cross-linked bovine serum albumin was examined. The chemiluminescence (CL) was followed with a low-light intensity video camera and imaging system attached to a circularly polarized microwave guide (2450 MHz) for heating the samples from 24 degrees C to 37 degrees C. Steady-state CL was maintained in the gels for 10 min. The intensity of the CL varied with temperature. When combined with MetHb in the same gel, GHP inhibited CL of MetHb from 83.6% to 98.2% over a fiftyfold concentration range of GHP. Although MetHb/GHP combination gels were inhibited, they generated a 6.12-fold CL per degree C change compared to a 0.19-fold per degree C change for MetHb gels and a 0.31-fold per degree C change for GHP gels. The data suggest an interaction between GHP and MetHb that inhibits the CL reaction, is not interfered with by large amounts of albumin, and is partially reversed by heating.

Animals↗
PubMed1989

Electrolyte transport in rabbit cecum. I. Effect of RDEC-1 infection.

To investigate the characteristics of intestinal ion and fluid secretion induced by the adherent, effacing enteropathogenic Escherichia coli strain RDEC-1, we infected weanling rabbits with 10(7)-10(8) RDEC-1 organisms and then studied cecal ion transport under short-circuit conditions in Ussing chambers. Results in tissues with confluent adherent organisms were compared with those in uninfected ceca and in ceca stimulated with dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP). The short-circuited cecum normally absorbed Na and Cl, secreted bicarbonate (as represented by the residual ion flux), and displayed a high rate of nondiffusional Na and Cl transport. RDEC-1 infection did not alter the short-circuit current (Isc), but it increased the conductance (Gt), decreased the potential difference (PD), abolished net Na absorption, and reversed Cl absorption to secretion. The changes in Na and Cl net fluxes may be explained by inhibition of a Na-Cl linked absorptive process. In contrast, DBcAMP significantly increased the Isc, PD, and Gt, decreased net Na flux, and abolished net Cl absorption by stimulating electrogenic Cl secretion. These results suggest that RDEC-1-induced changes in cecal ion transport are not mediated by cAMP. The reduction in Na-Cl linked absorption is consistent with anatomic changes in the apical surfaces of absorptive epithelial characteristic of effacing enteroadherence, whereas the increased conductance is consistent with tight junction disruption seen with RDEC-1 infection.

Biological Transport↗
PubMed1988

Green hemoprotein of erythrocytes: methemoglobin superoxide transferase.

Influences of base (pH 10), heat (50 degrees C), microwave radiation (2450 MHz, 103 +/- 4 W/kg), and hydrogen peroxide (5.6 mM) generated by glucose oxidase on oxidation of human oxyhemoglobin to methemoglobin were examined. Conversion of oxyhemoglobin to methemoglobin was followed by the difference in absorbancy of 540 or 542 nm and 576 nm wavelength light versus time. Fresh basic hemolysates auto-oxidized on heating with a zero order rate constant, implying that hemoglobin or another protein saturated with oxyhemoglobin catalyzed the oxidation. Simultaneous microwave irradiation inhibited thermally induced auto-oxidation on the average by 28.6%. However, there was great variability among samples and a decrease in auto-oxidation with aging of individual samples. The auto-oxidation rate was independent of initial oxyhemoglobin concentration. Oxidation of partially purified oxyhemoglobin by hydrogen peroxide was not influenced by microwave irradiation. Adding green hemoprotein isolated from human erythrocytes to the oxyhemoglobin/glucose oxidase reaction mixture yielded absorption spectra (500-600 nm) that were a combination of oxyhemoglobin, deoxyhemoglobin, and methemoglobin spectra. Green hemoprotein was labile in hemolysates but stable in a partially purified ferric form. These results imply that thermally unstable reduced green hemoprotein can reverse oxidation of oxyhemoglobin by hydrogen peroxide and could mediate the thermally induced and microwave inhibited auto-oxidation of oxyhemoglobin.

Erythrocytes↗
PubMed1988

Fitness evaluations and fitness findings in competitive junior tennis players.

Elite tennis players, as well as a large number of active recreational players, are involved in a sport that applies high repetitive loads that can create tension overload situations in certain key anatomic areas of the body and add to possible overload situations in other areas of the body. This results in patterns of inflexibility and weakness that can be demonstrated on a tennis-specific musculoskeletal exam, and that can be correlated with areas of increased injury occurrence. These players report conditioning programs that are, for the most part, inadequate to confer total conditioning of all the muscular parameters important in playing tennis. All of these factors, in addition to the frequency and type of playing, contribute to the occurrence of the overload injuries noted. These aspects need to be addressed in a preventative program for injury reduction. We do not believe that major changes in the way that tennis is played should be implemented until the effects of a proper preventative conditioning program are evaluated. The "ideal" conditioning program has not yet been found. While the exact composition of the program is in doubt, our studies allow us to recommend flexibility, strength, and endurance training for all athletes playing tennis at frequent intervals. This program should be guided by the findings on the preparticipation exam.

Adolescent↗
PubMedDate not supplied

Flexibility and anterior knee pain in adolescent elite figure skaters.

To investigate the relationship between thigh muscle flexibility and anterior knee pain in adolescent athletes, we examined 46 skaters. We taught them flexibility exercises and later retested 28 of them. Three fourths of the skaters who improved their quadriceps flexibility eliminated their pain. Two of the three skaters who lost flexibility developed pain. Analysis of all examinations showed that skaters with pain had tighter quadriceps muscles than those without pain. Poor hamstring flexibility was correlated with patellofemoral pain. This study shows that adolescent athletes may improve their flexibility after counseling and indicates a clear relationship between thigh muscle flexibility and anterior knee pain.

Adolescent↗