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Biomedical subjects

R Jones

Publications and source records attributed to R Jones.

At least 451 records · Page 25Linked to original sources
PubMed1995

Inhibition of acrosin by serpins. A suicide substrate mechanism.

The serpins antithrombin, protease nexin 1, and alpha 1-antitrypsin with a reactive-center arginine (Arg-alpha 1-antitrypsin) were found to inhibit the sperm protease acrosin with varying efficiency. The serpins were titrated against acrosin to determine their specific activity with respect to this enzyme. While antithrombin was fully active against acrosin, more than one molecule of Arg-alpha 1-antitrypsin and protease nexin 1 was required to inhibit one molecule of acrosin. In particular, only 2.7% of protease nexin 1 molecules interacting with acrosin formed stable complexes with the enzyme at 37 degrees C and this value decreased to 0.03% at 12 degrees C. N-terminal sequence analysis indicated that acrosin had cleaved protease nexin 1 at its reactive-center Arg-Ser bond. The results could be interpreted in terms of protease nexin 1 acting as a suicide substrate for acrosin; after the formation of an initial complex, the serpin partitioned between pathways yielding either inactivated (cleaved) serpin or a stable serpin-enzyme complex. The association rate constant (k(ass)) and inhibition constant (Ki) for the stable complexes were determined for each of the serpins by using slow-binding kinetics. The values of k(ass) were 2 x 10(5), 4 x 10(4), and 5 x 10(3) M-1 s-1 for Arg-alpha 1-antitrypsin, antithrombin, and protease nexin 1, respectively. The Ki values for the serpins were 1 nM or less. Heparin markedly accelerated the inhibition of acrosin by antithrombin and protease nexin 1; at the optimal concentration, the degree of heparin acceleration of the inhibition rate was 250- and 500-fold for antithrombin and protease nexin 1, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrosin↗
PubMed1995

The monkey ESP14.6 mRNA, a novel transcript expressed at high levels in the epididymis.

A screening strategy designed to identify cloned cDNAs encoding abundant Macaca fascicularis epididymal transcripts has yielded a clone corresponding to a 1.03-kb transcript present at high levels in the epididymis. Following library rescreening, DNA sequence analysis of several near full-length clones predicts a novel, 151-amino-acid protein, epididymal secretory protein 14.6 (ESP14.6), which contains a strong candidate signal peptide characteristic of secretory proteins.

Amino Acid Sequence↗
PubMed1995

Quantitation of mixtures from two-dimensional data sets using orthonormal functions.

The use of orthogonal polynomials in mixture analysis has been extended to two-dimensional data sets. Orthonormal two-dimensional functions, constructed from Legendre polynomials, are fitted to the standard and test data sets. Weighted combinations of coefficients are used to correct for interferences from other components whilst quantifying the analyte of interest. The general procedure can be extended to data sets of higher dimensionality or to different orthogonal basis sets.

Acyclovir↗
PubMed1995

In vitro activity of beta-lactamase inhibitors against clinical isolates of Acinetobacter species.

Acinetobacter is an important cause of nosocomial infections, and it is often resistant to many antibiotics. In a search for alternative agents, three beta-lactamase inhibitors (sulbactam, clavulanate, and tazobactam) and five beta-lactam antibiotics (imipenem, ceftazidime, ceftriaxone, cefotaxime, and piperacillin) were tested against 68 unique clinical isolates of Acinetobacter species. Minimum inhibitory concentrations were determined by a broth microdilution method. Using temperature sensitivity testing, we identified 59 strains as Acinetobacter baumannii, one as Acinetobacter haemolyticus, and eight as indeterminate biotype species. We demonstrated 41 of 59 (70%) strains of A. baumannii to be multiply resistant (susceptible only to amikacin and imipenem), whereas all the nonbaumannii strains were not. Imipenem was the most active agent among the compounds investigated. All three beta-lactamase inhibitors had strong intrinsic activity, with sulbactam being the most active agent among the beta-lactamase inhibitors studied.

Acinetobacter↗
PubMed1995

Endothelium is a target organ of parathyroid secretions in genetic hypertensive rats.

We investigated the relationships between vascular endothelium and parathyroid function. Blood pressure (BP), circulating endothelins (ETs) and atrial natriuretic peptide (ANP), and BP responses to parathyroid hormone (PTH) and NG-nitro-L-arginine methyl ester (L-NAME) were measured in parathyroidectomized (PTx), PTx and fed a Ca2+ enriched diet (PTx-HCa) and sham SHR.22 weeks after surgery, BP was significantly decreased in PTx and PTx-HCa, plasma ETs levels were increased, whereas ANP levels were decreased. In anesthetized rats, BP increase induced by L-NAME was greater in PTx-HCa than in sham group, indicating increased endogenous nitric oxide release in hypoparathyroid rats. The hypotensive response to PTH remained unchanged. These data demonstrate that endothelium is activated in long-term hypoparathyroid SHR, reflecting an adaptative response to decreased BP.

Animals↗
PubMed1995

Facial Nerve Monitoring under Neuromuscular Blockade.

The characteristics of facial nerve electromyography at various levels of neuromuscular blockade are unclear. Partial blockade is well known to facilitate anesthetic safety and management. However, the use of neuromuscular blockage in many skull base procedures is avoided to allow intraoperative facial nerve monitoring.We studied the influence of various levels of neuromuscular blockade on facial nerve stimulation in the New Zealand white rabbit. The facial nerve was exposed in the middle ear of six rabbits. Using electromyographic-type facial nerve monitor, we recorded the facial electromyography signals in these rabbits at increasing levels of vecuronium-induced neuromuscular blockade. All animals demonstrated reliable facial electromyography response at all levels of partial neuromuscular blockade (P < .02). Five of the six animals could be monitored throughout complete blockade. These results clearly demonstrate that rabbit facial electromyography monitoring is possible under neuromuscular blockade. The effect of neuromuscular blockers on facial electromyography monitoring deserves further study, as partial blockade would greatly facilitate the management of anesthesia in otologic, neurotologic, and skull base surgery.

Journal Article↗
PubMed1995

Peer review.

Explore the source record for details and available documents.

Humans↗
PubMed1995

A psychiatrist-rated battery of measures for assessing the clinical status of psychiatric inpatients.

Despite the increasing demand for outcome assessment measures, no published reports have provided a standardized way to assess psychiatric inpatients that includes diagnosis and observer ratings of psychopathology. This paper reviews general principles for selecting outcome assessment measures, proposes a battery of instruments based on already available measures to assess clinical status in psychiatric inpatients, reviews methods of implementing the battery in an academic inpatient psychiatric setting, and presents preliminary data on its interrater reliability, construct validity, and range of response to acute hospitalization. Preliminary results suggest that the battery may be useful for resident and medical student education and for enhancing quality assurance and continuous quality improvement.

Comorbidity↗
PubMed1995

A prevalence study of age-associated memory impairment.

BACKGROUND: Age-associated memory impairment (AAMI) describes a non-disease ageing-related decline in memory. Pharmacological treatment trials have been reported and DSM-IV has introduced a term for the disorder. No prevalence study with the original criteria has previously been published. METHOD: An age-stratified sample was taken of 50-95-year-olds registered with a local health centre. Diagnosis of AAMI was made by questionnaire, cognitive testing, and medical and psychiatric assessment. RESULTS: Prevalence rates for the total population and for the over-50s were estimated to be 5.8% and 18.5%, respectively. These rates are dramatically affected by minor alterations to individual criteria. CONCLUSIONS: It appears AAMI is less common than previous estimates suggested, although the diagnostic criteria do not satisfactorily define people with an age-related decline in memory. Complaint of memory decline is more strongly correlated with measures of affect and personality than with measures of current memory test performance or estimates of memory decline.

Age Factors↗
PubMed1995

Assessing patient willingness to reveal health history information.

A survey was designed to determine how willingly patients reveal personal health information on dental health history forms. After giving informed consent, 107 patients at a university dental hygiene program completed a 10-item survey privately and anonymously. The results suggest that a significant number of patients provide inaccurate or incomplete information to questions routinely asked on the dental health history form.

Adult↗
PubMed1995

Pulmonary edema in association with an intravenous infusion of sulprostone.

We encountered a patient with pre-eclampsia who developed pulmonary edema whilst receiving an infusion of sulprostone. Recent evidence suggests that pulmonary hypertension following the administration of prostaglandins may result from stimulation of an EP3 or thromboxane receptor in the pulmonary artery. This has implications for therapeutic use of prostaglandins.

Abortifacient Agents, Nonsteroidal↗
PubMed1995

Gastro-oesophageal reflux disease in general practice.

Symptoms of reflux-like dyspepsia and gastro-oesophageal reflux disease (GORD) are common problems in the community and in general practice. The 1-year prevalence of reflux-like dyspepsia is in the region of 30%, with many patients experiencing a range of other symptoms in addition to the principal complaint of retrosternal pain or burning. Although only a minority, about one-quarter, of these patients consult general practitioners about their problems, many of them have had symptoms for several years, and experience symptoms on a frequent, often daily, basis. The decision to consult a general practitioner often depends more upon patients' anxieties about the possibility of heart disease and cancer than on symptom severity. General practitioners need to address these issues, as well as attempting to make a safe, clinical diagnosis; this is aided by the findings that, at least in patients under the age of about 45, a reasonably confident clinical diagnosis can be made on the basis of symptoms alone, although older patients and those in whom alarm symptoms are present require timely investigation. The increasing availability of open-access endoscopy means that many of these patients can be managed entirely in general practice without the need for specialist referral. Management in general practice begins with a clear explanation of the mechanisms and significance of GORD and a direct response to patients' anxieties. Lifestyle factors may require modification before drug therapy begins.(ABSTRACT TRUNCATED AT 250 WORDS)

Family Practice↗
PubMed1995

Development of a postal health status questionnaire to identify people with dyspepsia in the general population.

OBJECTIVE: To develop and validate a postal health status questionnaire which will identify people with dyspepsia in the general population. DESIGN: Validation against telephone interview and post re-post determination of reliability. SETTING: A general practice population in the north of England. SUBJECTS: A random sample of adults aged 20-69 years inclusive chosen from the general population. MAIN OUTCOME MEASURES: Validity has been checked against telephone interview. A kappa statistic has been calculated for each question and clinical category. RESULTS: Compared with interview the questionnaire is a valid, comprehensive and easily understood record of symptomatology. The kappa statistics (mean value 0.92) indicate a very reliable questionnaire. CONCLUSION: The questionnaire accurately and reliably identifies people with dyspeptic symptoms.

Adult↗