Search PubMed⌕ Search

Biomedical subjects

R Ryan

Publications and source records attributed to R Ryan.

At least 19 recordsLinked to original sources
PubMed1997

The effects of ion implantation on rate of tooth movement: an in vitro model.

Recently, the ion-implantation process has been applied to orthodontic wires. By altering the surface composition of a wire, the ion-implantation process supposedly decreases the frictional forces produced during tooth movement. The purpose of this study was to compare the amount of tooth movement produced by different orthodontic wire compositions, under identical conditions, by using an in vitro model. The wires tested were stainless steel, nickel-titanium (control and ion implanted), and beta-titanium (control and ion implanted). The amount of tooth movement was measured and compared. Results demonstrate that, stainless steel produced the least frictional force during in vitro tooth movement, followed by ion-implanted nickel-titanium, ion-implanted beta-titanium, untreated nickel-titanium, and finally, untreated beta-titanium. A Wilcoxon rank sum test showed statistically significant differences in the amount of movement seen with the ion-implanted wires when compared with their untreated counterparts.

Analysis of Variance↗
PubMed1996

Concurrent Lyme disease and babesiosis. Evidence for increased severity and duration of illness.

OBJECTIVE: To determine whether patients coinfected with Lyme disease and babesiosis in sites where both diseases are zoonotic experience a greater number of symptoms for a longer period of time than those with either infection alone. DESIGN: Community-based, yearly serosurvey and clinic-based cohort study. SETTING: Island community in Rhode Island and 2 Connecticut medical clinics from 1990 to 1994. STUDY PARTICIPANTS: Long-term residents of the island community and patients seeking treatment at the clinics. MAIN OUTCOME MEASURES: Seroreactivity to the agents of Lyme disease and babesiosis and number and duration of symptoms. RESULTS: Of 1156 serosurvey subjects, 97 (8.4%) were seroreactive against Lyme disease spirochete antigen, of whom 14 (14%) also were seroreactive against babesial antigen. Of 240 patients diagnosed with Lyme disease, 26 (11%) were coinfected with babesiosis. Coinfected patients experienced fatigue (P = .002), headache (P < .001), sweats (P < .001), chills (P = .03), anorexia (P = .04), emotional lability (P = .02), nausea (P = .004), conjunctivitis (P = .04), and splenomegaly (P = .01) more frequently than those with Lyme disease alone. Thirteen (50%) of 26 coinfected patients were symptomatic for 3 months or longer compared with 7 (4%) of the 184 patients with Lyme disease alone from whom follow-up data were available (P < .001). Patients coinfected with Lyme disease experienced more symptoms and a more persistent episode of illness than did those (n = 10) experiencing babesial infection alone. Circulating spirochetal DNA was detected more than 3 times as often in coinfected patients as in those with Lyme disease alone (P = .06). CONCLUSIONS: Approximately 10% of patients with Lyme disease in southern New England are coinfected with babesiosis in sites where both diseases are zoonotic. The number of symptoms and duration of illness in patients with concurrent Lyme disease and babesiosis are greater than in patients with either infection alone. In areas where both Lyme disease and babesiosis have been reported, the possibility of concomitant babesial infection should be considered when moderate to severe Lyme disease has been diagnosed.

Adolescent↗
PubMed1996

Comparison of PCR with blood smear and inoculation of small animals for diagnosis of Babesia microti parasitemia.

The specific diagnosis of babesiosis, which is caused by the piroplasm Babesia microti, is made by microscopic identification of the organism in Giemsa-stained thin blood smears, detection of babesial antibody in acute-and convalescent-phase sera, or identification of the organism following the injection of patient blood into laboratory animals. Although rapid diagnosis can be made with thin blood smears, parasites are often not visualized early in the course of infection. PCR is a new, rapid diagnostic technique for the detection of Babesia spp. that has not yet been systematically evaluated. We conducted a blinded study of the sensitivity, specificity, and reproducibility of the PCR-based test with patients with babesiosis and a group of asymptomatic subjects residing in a region in southern New England where babesiosis is enzootic. Among 19 patients with recent babesial illness, we found that PCR was as sensitive and specific as the use of Giemsa-stained blood smears and inoculation of hamsters. Among asymptomatic subjects, the PCR result was positive for 3 persons with recent babesial infection and was negative for 41 persons without previous babesial infection. We conclude that the B. microti PCR procedure is sufficiently sensitive, specific, and reproducible for use in the diagnosis of acute babesiosis.

Animals↗
PubMed1996

Efficacy of immunoglobulin M serodiagnostic test for rapid diagnosis of acute babesiosis.

To evaluate the efficacy of an immunoglobulin M indirect immunofluorescent-antibody procedure for diagnosing acute babesiosis, we tested patients with acute babesiosis from a site in New England where the disease is enzootic. The sensitivity of the test was 91%, the specificity was 99%, the positive predictive value was 86%, and the negative predictive value was 99%. This B. microti immunoglobulin M indirect immunofluorescent-antibody procedure is sufficiently sensitive, specific, and reproducible for use in the routine clinical diagnosis of acute babesiosis.

Acute Disease↗
PubMed1996

The social marketing of project ARIES: overcoming challenges in recruiting gay and bisexual males for HIV prevention counseling.

This paper reports on the development, implementation, and evaluation of a social marketing campaign designed to recruit clients Project ARIES, and AIDS prevention study funded by the National Institute of Mental Health. Marketing channels employed for the campaign included advertising in the gay press, generating coverage in the mainstream press, distributing materials to HIV testing centers and other health and social service providers, and displaying posters in gay bars and baths. While these approaches all succeeded in eliciting inquiries from individuals engaging in high risk sexual behaviors, they differed in several respects, including their ability to reach specific subgroups that are often underserved by more traditional programs, such as men of color, younger men, and men who self-report as being closeted. Promotional materials displayed in gay bars and baths resulted in the highest percentage of callers who, after inquiring about the program, decided to participate in the counseling. Coverage in the mainstream press was the most successful in reaching closeted men, men who were less active in the gay community, and individuals who did not self-identify as gay. Display and classified ads in the gay press produced the highest number of initial inquiries. Finally, recruitment of participants via materials distributed to HIV test sites and other service providers was the most effective in reaching men who were HIV-positive.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Biocompatible dialysis membranes and acute renal failure: a study in post-operative acute tubular necrosis in cadaveric renal transplant recipients.

Previous experimental and human data suggests a detrimental effect on the course of acute renal failure related to exposure of blood to artificial dialysis membranes of poor biocompatibility. We performed a 2.5-year prospective randomized trial to compare the clinical course of acute renal failure (post-operative ischemic acute tubular necrosis, ATN) in patients receiving a cadaveric renal transplant requiring supportive hemodialysis in the immediate post-transplant setting. Patients were randomized to either a cuprophane or polymethylmethacrylate (PMMA) conventional hollow fiber dialyzer. All patients received a standard immunosuppressive regimen which included induction therapy with either horse anti-thymocyte gamma globulin (ATGAM) or the murine anti-CD3 monoclonal antibody (OKT3). Of 53 patients randomized, 17 were excluded (2 for intervening biopsy-proven rejection prior to recovery from ATN, 10 for primary graft nonfunction and 5 for other reasons), leaving 36 evaluable cases of uncomplicated ATN, 18 in each group. There was no difference by age, race, gender, cause of ESRD, immunosuppressive regimen, cold or warm ischemia time, use of pre-transplant dialysis, percent oliguria or the incidence of intra-dialytic hypotension between the 2 groups. There was no difference in the mean time to recovery from ATN posttransplant (8.9 days in the cuprophane group vs 9.5 days in the PMMA group, p = NS) or in the average number of hemodialysis treatments required (3.6 in both groups, p = NS). There was also no difference in long term allograft outcome in terms of the nadir serum creatinine, the number of episodes of subsequent acute rejection or in the development of chronic rejection. An intent-to-treat analysis of all 53 originally randomized patients similarly yielded no significant differences. A subsequent, non-randomized study using a membrane of intermediate biocompatibility (Hemophan) also showed no difference in recovery time from ATN. Bioincompatible membranes do not seem to have a significant clinical impact on the course of recovery of this form of acute renal failure. The striking benefits of biocompatibility in the course of ARF seen in other human trials may relate more to the non-renal systemic toxic effects of bioincompatibility.

Adult↗
PubMed1995

Stabilization of ribonuclease B activity by concentrated xylose solutions.

Ribonuclease B has become a paradigm as a simple example of an N-linked glycoprotein. We have found that certain affinity-purified preparations of this enzyme demonstrated a pronounced tendency to lose activity if stored as dilute aqueous solutions. Such inactivation is accelerated by the presence of NaCl, but can be counteracted by inclusion of high (1 mol/l) concentrations of xylose. Enzyme activity cannot be restored by addition of xylose after storage of the enzyme. In marked contrast to alpha-methyl-mannoside, xylose does not prevent ribonuclease B from binding to concanavalin A and so may be used to stabilize the enzyme during purification by lectin affinity chromatography.

Chromatography, Affinity↗
PubMed1995

A prospective randomised trial of the use of sodium bicarbonate and hydrogen peroxide ear drops to clear a blocked tympanostomy tube.

This randomised prospective trial compared the efficacy of sodium bicarbonate and hydrogen peroxide ear drops in clearing a blocked tympanostomy tube. Tympanostomy tubes, 110 in number, obstructed with blood or inspissated secretions were randomised into treatment and control groups. Details of the operative procedure were retrospectively collected from the patients notes. The patients were reviewed after 2 weeks for both clinical and tympanometric evidence of clearance of the tube and evidence of complications of the drops. There was no significant therapeutic advantage between the two drops (P > 0.9), but in both treatment arms there was a significant therapeutic advantage over a period of observation (P < 0.05 in both groups). Otorrhoea and pain on instilling the drops occurred with equal incidence in both treatment groups. As obstruction of tympanostomy tubes is a common occurrence which often prompts surgical reventilation, there is great potential for cost savings if conservative treatment can be used effectively. The treatments for obstructed tympanostomy tubes are reviewed and methods of prevention of this common occurrence are discussed.

Acoustic Impedance Tests↗
PubMed1995

Mastoidectomy audit: results of the Royal College of surgeons of England comparative audit of ENT surgery.

This paper presents the results of a national comparative audit of mastoid surgery, retrospectively analysing 611 operations by 55 consultants. Confidentiality for both patient and surgeon was assured. For cholesteatoma 80% of mastoidectomies performed were open cavity procedures and for other middle ear disease 58% used an intact canal wall technique. Thirty-two surgeons used only an open cavity mastoidectomy for cholesteatoma during the period of the audit. There was a statistically significantly greater number of wet ears with open cavities than with closed cavities, but the frequency of the operator did not correlate with the dry ear rate. Ten serious complications (facial palsy and dead ear) were recorded. All occurred in open cavity mastoidectomies. The post-operative hearing status was unknown in 40% of patients.

Cholesteatoma↗
PubMed1994

Posttraumatic stress disorder in persons with developmental disabilities.

Persons with developmental disabilities are more frequently abused physically, emotionally and sexually than nondisabled persons (Ammerman, Van-Hasselt, Herson, McGonigle, & Lubetsky, 1989; Sobsey, Gray, Pyper, & Reimer-Heck, 1991). Persons with developmental disabilities are susceptible to the full range of psychiatric disorders (Szymanski, Madow, Mallory, Menolascino, & Pace, 1991). There has been no comprehensive study of posttraumatic stress disorder (PTSD) in this population (Hudson & Pilek, 1990), a recent textbook of mental health and mental retardation does not contain index listings on this condition (Fletcher & Menolascino, 1989), and psychometric tests currently proposed for use with the retarded do not examine for this condition (Aman, Watson, Singh, Turbott, & Wilsher, 1986). In this preliminary study, descriptive data from 51 persons with developmental disabilities who met DSM-IIIR criteria for posttraumatic stress disorder are reported. The majority of cases were detected upon routine initial psychiatric interview and record review. Demographics, family histories, and comorbid psychiatric conditions are described. In this sample all patients who received comprehensive recommended treatment improved.

Adult↗
PubMed1994

Single grade specialist training in otolaryngology--a survey of attitudes among present and recent trainees.

The authors present the results of a postal questionnaire about possible advantages, disadvantages, and logistics of a single grade training scheme. Replies were received from 13 recently appointed consultants and 42 otolaryngologists in training. The majority (43) were in favour of a single grade training scheme, although it was felt that certain potential problems would need to be carefully addressed, particularly the potential for narrow clinical exposure and the difficulties inherent in early selection for higher surgical training. It was also felt that for such schemes to work, considerable extra consultant time would need to be set aside purely for teaching. The respondents' ideal training scheme is outlined.

Education, Medical, Graduate↗
PubMed1994

Diagnosis of babesiosis: evaluation of a serologic test for the detection of Babesia microti antibody.

To assess the possibility of standardization of a commonly used indirect immunofluorescent antibody (IFA) test for detection of Babesia microti antibody in human sera, the results from four reference laboratories were compared. Patients with babesiosis from southern New England (n = 25) and subjects with no history of babesiosis from southern New England (n = 55) and Iceland (n = 50) were enrolled in the study. Anti-Babesia antibody titers were determined in a blinded fashion by IFA test. The range of test results in the four laboratories was 88%-96% sensitivity, 90%-100% specificity, 69%-100% positive predictive value, and 96%-99% negative predictive value. Interlaboratory and intralaboratory concordance ranged from 84% to 85% and 94% to 100%, respectively. This B. microti IFA procedure is a sensitive, specific, and reproducible method for diagnosing babesiosis and is suitable for use as a standard in laboratories testing human sera for B. microti antibody.

Adult↗
PubMed1994

Fluid replacements after squash: an analysis of the effects of several fluid regimens on exercise-related metabolic changes.

We studied the effects of several fluid replacements taken after squash on exercise-related metabolic responses. 12 subjects played 5 games and after each game were assigned one of the following, receiving a different one each time: (1) no fluid replacement, or 500 ml of (2) water, (3) electrolyte solution, (4) glucose solution or (5) a glucose/electrolyte 'sports' drink. Circulating levels of lactate, free fatty acids, glucose, potassium, sodium and plasma osmolality were measured at rest and at 5, 15, 30 and 60 min after games. There were significant changes over time for all measured variables (p < 0.001). The only effect of these drinks was by the glucose-containing drinks, which resulted in significant elevation of blood glucose levels (p < 0.001); no effects on circulating electrolyte levels were demonstrated. In conclusion, while fluid replacements may increase glucose levels, electrolyte levels are not affected by drinks which are commonly used after squash.

Adult↗
PubMed1993

Cytokine indices in Alzheimer's temporal cortex: no changes in mature IL-1 beta or IL-1RA but increases in the associated acute phase proteins IL-6, alpha 2-macroglobulin and C-reactive protein.

Recent immunocytochemical data have demonstrated increases in interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and the IL-6-inducible acute phase protein, alpha 2-macroglobulin (alpha 2-M), in Alzheimer's disease (AD) brains. We investigated the levels of these proteins quantitatively using ELISA procedures and determined if increases in IL-1 beta were compensated for by a parallel increase in the endogenous interleukin-1 receptor antagonist (IL-1RA). Comparing control vs. Alzheimer's temporal cortex, we examined mature IL-1 beta, IL-1RA, IL-6, alpha 2-M and C-reactive protein (CRP). The specificities of the ELISA procedures were verified by serial dilutions of the samples; by chromatofocusing, and by Sephadex G-150 gel filtration. There were no differences in the levels of mature IL-1 beta or IL-1RA in AD and control brains. However, IL-6 levels were detectable in 14 of the 16 Alzheimer samples but only 2 of the 14 control samples. There were also significant increases seen in alpha 2-M and CRP levels in the Alzheimer's group compared to controls. These data support previous studies demonstrating a possible up-regulation of neuroimmune function in Alzheimer's cortex; however, we cannot determine, at this time, if this immune reaction is initiated by IL-1 beta.

Acute-Phase Proteins↗
PubMed1993

Cloning, sequencing, and functional studies of phenobarbital-inducible forms of cytochrome P450 2B and 4B expressed in rabbit kidney.

Expression of several forms of cytochrome P450 2B and of P450 4B1 in rabbit kidney was investigated by cloning from cDNA libraries constructed with renal mRNA from animals treated with phenobarbital. Isolation and sequencing of several cDNAs demonstrated that: (i) cytochrome P450 2B-B0 can be found in rabbit kidney along with a newly discovered form of P450 2B termed "P450 2B-Bx." P450 2B-Bx differs from P450 2B-B0 at 25 nucleotide positions and at four positions in the derived sequence of 491 amino acids. Two previously identified forms of cytochrome P450 2B, 2B-B1 and 2B-B2, are not detected in rabbit kidney. cDNA encoding cytochrome P450 4B1 was also cloned from the kidney library and found to be identical in sequence to cDNAs cloned from rabbit hepatic and pulmonary libraries. Analysis of renal mRNA indicates that forms of cytochrome P450 2B and P450 4B1 are expressed in a number of species but induced by phenobarbital in rabbit only (4B1) or rabbit and hamster (2B). Relatively high levels of mRNA related to P450 4B1 were detected in samples from untreated and phenobarbital-treated mice. Analysis of protein by immunoblotting was less sensitive but produced results consistent with those obtained by analysis of mRNA; protein related to cytochrome P450 2B was detected in renal microsomal samples from rabbit and hamster (phenobarbital > untreated), and protein related to P450 4B1 in samples from rabbits (phenobarbital > untreated) and mice (phenobarbital = untreated). The four forms of cytochrome P450 2B were expressed in COS-7 cells, and their activities were evaluated with androstenedione, testosterone, and 7-ethoxycoumarin as substrates. Three of the P450 2B forms, B0, B1, and Bx, metabolize these substrates in a manner characterized by preference for 16 beta-hydroxylation of androstenedione, low testosterone 16-hydroxylation, and high ethoxycoumarin O-deethylation. The fourth form, P450 2B-B2, is catalytically distinct from the others, with activities characterized by high androstenedione 16 alpha- and 15 alpha-hydroxylation and high testosterone 16-hydroxylation. Since P450 2B-B2 is catalytically distinct from the other forms, the metabolic profiles of phenotypes that include P450 2B-B2 might differ significantly from those of phenotypes that lack P450 2B-B2.

Amino Acid Sequence↗