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Biomedical subjects

R Ryan

Publications and source records attributed to R Ryan.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1993

Hemisphericity style, sex, and performance on a letter-detection task.

Subjects classified by scores on the Preference Questionnaire as preferring either a left- or a right-hemisphericity style were asked to read a one-page passage and to circle each letter t they encountered as they read the passage. There were no statistically significant differences in letter detection between the 58 right- and the 64 left-style scorers. However, contrary to previous findings, the 73 women detected significantly more ts, including unsounded ts, than the 55 men. Our results suggest that hemisphericity style is not an important factor in letter detection.

Adolescent↗
PubMed1993

Nasal packing after routine nasal surgery--is it justified?

Ninety-five patients undergoing routine nasal surgery were enrolled into a randomized, prospective trial to investigate the efficacy and morbidity of nasal packing. The patients were randomized to receive a bismuth iodoform paraffin paste (BIPP) pack, a Telfa pack or no pack. Patients for septal surgery were randomized between the BIPP and Telfa groups only. They were independently randomized to receive or not receive, a silastic nasal splint for the first post-operative week. Post-operative pain levels were analysed using a visual analogue scale. Mean pain scores were increased 50 per cent by the use of nasal packs and pack removal, particularly BIPP which, was a most painful event (p < 0.001). Reactionary haemorrhage occurred in only two patients (2.1 per cent), both of whom had packs in situ. Vestibulitis was unique to the patients with a silastic splint, who were packed with BIPP, occurring in 21 per cent of them. Similarly septal perforation was unique to this group. There was no significant difference in the incidence of adhesions between the groups which received packs and those who did not. Routine nasal packing, especially with BIPP, would seen difficult to justify in view of the increased pain levels and increased complications which occur without any demonstrable benefit in the majority of patients. Therefore packing should be reserved for cases where there is concern about persistent haemorrhage. In these cases Telfa would be preferable to BIPP.

Adult↗
PubMed1993

Early Lyme disease: a flu-like illness without erythema migrans.

The existence of a form of early Lyme disease characterized by a flu-like illness without erythema migrans is controversial. To confirm the existence and define the clinical characteristics of the flu-like illness without erythema migrans of localized Lyme disease, the authors studied patients from a Lyme disease endemic area of Connecticut who visited their primary care physicians with an undefined flu-like illness. Patients kept a diary of their symptoms. Acute and convalescent sera were obtained. The diagnosis of Lyme disease was based on the appearance of IgM or IgG antibodies to Borrelia burgdorferi as demonstrated by both enzyme-linked immunosorbent assay and immunoblot assay. Twenty-four untreated patients were studied. In five patients acute serologic evidence of Lyme disease developed. The flu-like illness in these five patients was characterized by fever and fatigue and resolved spontaneously in 5 to 21 days. Symptoms recurred in three of these five patients. The existence of a flu-like illness without erythema migrans of early Lyme disease has been clearly established. Prospective, controlled studies are needed to better define its incidence, characteristics, and prognosis so that appropriate diagnostic and therapeutic strategies can be developed.

Acute Disease↗
PubMed1992

NMDA-, but not kainate- or quisqualate-dependent increases in cerebellar cGMP are dependent upon monoaminergic innervation.

As previously reported, intracerebellar injections of D-serine, quisqualate and kainate elevated mouse cerebellar cGMP levels. Similarly, activation of endogenous excitatory amino acid utilizing neurons with harmaline or pentylenetetrazole also increased cerebellar cGMP. We previously have demonstrated that the harmaline- and pentylenetetrazol-dependent cGMP increases are NMDA receptor mediated. In this report we further demonstrate that NMDA-dependent increases in cGMP are dependent upon monoaminergic innervation of the cerebellum, while kainate- and quisqualate-dependent cGMP increases are independent of such innervation.

Animals↗
PubMed1992

Excitatory amino acid signal transduction in the hippocampus: role of noradrenergic afferents and nitric oxide in cGMP increases in vivo.

Previous studies have demonstrated that excitatory amino acid (EAA)-dependent increases in cerebellar cGMP are dependent upon the prior activation of nitric oxide (NO) synthase. Additionally, the actions of NMDA, but not kainate or quisqualate, in elevating cerebellar cGMP have been shown to be dependent upon intact noradrenergic innervation of the cerebellum. In the current study we extended these observations to the hippocampus and again found that EAA-dependent increases in hippocampal cGMP also involve prior formation of NO. And as in the case of the cerebellum, NMDA-dependent increases in hippocampal cGMP involve prior release of norepinephrine which in turn apparently activates an alpha 1-adrenergic receptor to elicit cGMP increases. In toto, these data suggest that a key role of NMDA receptors in these brain regions is to presynaptically regulate the release of norepinephrine, thereby modulating the tone of this monoaminergic system. This may be a general principle which needs experimentation in other terminal fields of noradrenergic pathways.

Analysis of Variance↗