Biomedical subjects

G Kent

Publications and source records attributed to G Kent.

At least 55 records · Page 3Linked to original sources

PubMed1995

The use of deception in nursing.

Arguments about the morality of the use of deception in patient care have been conducted largely in an empirical vacuum, with few data about the situations in which deception occurs. Do staff frequently deceive their patients and, if so, under what conditions? Can the consequences of deception always be foreseen? What justifications do staff use to explain their behaviour? The small-scale study reported here on the uses of deception by nurses when attempting to reassure patients provides information on these questions. The results suggest that deception can have deleterious effects on trust and increase the emotional distance between patients and staff.

Beneficence↗

PubMed1995

Penile absorption of EMLA cream in piglets: implications for use of EMLA in neonatal circumcision.

EMLA (eutectic mixture of lidocaine and prilocaine) cream is currently not recommended for use in infants < 1 month of age because of the potential risk of methemoglobinemia as a result of the o-toluidine metabolite of prilocaine. We studied bioavailability and changes in methemoglobin levels following topical penile exposure to 1 g of EMLA cream for 1 hour in piglets. Lidocaine, prilocaine, and o-toluidine concentrations were measured simultaneously using a high-performance liquid chromatography method. The systemic bioavailability of EMLA was low: 4.0 +/- (SD) 4.7% for lidocaine (range 0-13.6; n = 8) and 7.2 +/- 5.7% for prilocaine (range 0-14.5; n = 8). The ratio between exposure to o-toluidine with EMLA versus intravenous administration (i.e., AUCEMLA/AUCIV; see text) was also low: 4.2 +/- 9.3% (range 0-28.6; n = 9). The mean maximum methemoglobin value after intravenous administration was 1.23 +/- 0.64% (range 0.5-3.0; n = 12) and after penile application 0.99 +/- 0.36% (range 0.5-2.0; n = 12). The methemoglobin value was elevated significantly above baseline after intravenous administration (p = 0.03), but not after penile application of EMLA. These findings suggest that penile administration of 1 g of EMLA may be safe for neonatal circumcision, but further study is required.

Absorption↗

PubMed1994

Simultaneous determination of lidocaine, prilocaine and the prilocaine metabolite o-toluidine in plasma by high-performance liquid chromatography.

An HPLC assay is described for the measurement of prilocaine and lidocaine (components of the local anesthetic cream EMLA) as well as the prilocaine metabolite, o-toluidine, in plasma. The method uses UV detection, is simple, sensitive and most important, only a single 200-microliters plasma sample is needed for simultaneous analysis of prilocaine, lidocaine and o-toluidine with a detection limit of 4 ng/ml. The plasma, together with the internal standard (bupivacaine) is extracted with diethyl ether under alkaline conditions, followed by the extraction of the analytes from the organic phase into dilute sulphuric acid. An aliquot of the acid extract is injected onto the HPLC system and the effluent is monitored by a UV detector.

Animals↗

PubMed1994

Self-reported long-term effects of diving and decompression illness in recreational scuba divers.

The aim of this study was to examine the long-term effects of neurological decompression illness (NDCI) on recreational divers. Thirty-seven divers who had been treated for neurological decompression illness at least 2 years previously, and a control group of 50 divers with no history of decompression illness, responded to a postal questionnaire. Divers in the accident group reported more symptoms of neurological damage, were more likely to believe that diving had a deleterious effect on their health and were more likely to indicate symptoms of psychiatric morbidity. The quantity of diving in the year preceding the survey was associated with reports of neurological damage in both groups and with symptoms of psychiatric morbidity in the accident group. Although requiring confirmation from a longitudinal study, these results suggest that recreational diving can have negative long-term consequences for health, particularly after decompression illness.

Adult↗

PubMed1994

The relationship between disease severity, disability and psychological distress in patients undergoing PUVA treatment for psoriasis.

BACKGROUND: Patients suffering from severe psoriasis report high levels of personal distress and disability as a result of their disease. OBJECTIVE: The purpose of this study was to examine the relationship between disease severity, personal distress and disability. METHODS: Twenty-two patients provided a self-rating of disease severity and completed the Psoriasis Disability Index (PDI) and the General Health Questionnaire (GHQ). A dermatologist provided a clinical assessment from the case notes. RESULTS: Although the clinical assessment was not related to patient ratings, patient-rated severity scores, GHQ and PDI were correlated with each other. GHQ could only be predicted by disease severity when it was mediated by PDI scores. CONCLUSIONS: These results indicated that psoriasis affects psychological distress through its effects on the patients' everyday lives.

Attitude to Health↗

PubMed1993

A human somatostatin receptor (SSTR3), located on chromosome 22, displays preferential affinity for somatostatin-14 like peptides.

We report here on the cloning of a human intronless gene encoding a member of the G-protein linked somatostatin (SST) receptor subfamily, termed SSTR3. Based on the deduced amino acid sequence, this gene encodes a 418 amino acid protein displaying sequence similarity, particularly within putative transmembrane domains, with the recently cloned human SSTR1 (62%), SSTR2 (64%) and SSTR4 (58%) receptors. Membranes prepared from COS-7 cells transiently expressing the human SSTR3 gene bound [125I]Leu8,D-Trp22,Tyr25 SST-28 in a saturable manner with high affinity (approximately 200 pM) and with rank order of potency (D-Trp8 SST-14 > SST-14 > SMS-201-995 > SST-28) indicative of a somatostatin-14 selective receptor. The pharmacological profile of the expressed human SSTR3 receptor is similar but not identical to that reported for the rat homolog [(1992) J. Biol. Chem. 267, 20422] where the peptide selectivity is SST-28 > or = SST-14 >>> SMS-201-995. Northern blot analysis reveals the presence of an SSTR3 mRNA species of approximately 5 kb in various regions of the monkey brain, including the frontal cortex, cerebellum, medulla, amygdala, with little or no SSTR3 mRNA detectable in brain regions such as the striatum, hippocampus, and olfactory tubercle. The SSTR3 receptor gene maps to human chromosome 22. The existence of at least four distinct human genes encoding somatostatin-14 selective receptors with diverse pharmacological specificities may help to account for some of the multiple biological actions of somatostatin under normal and pathological conditions.

Amino Acid Sequence↗

PubMed1993

Multiple gene transcripts of the somatostatin receptor SSTR2: tissue selective distribution and cAMP regulation.

The rodent SSTR2 mRNA has been reported to be alternatively spliced to generate long (SSTR2A) and short (SSTR2B) receptor isoforms which differ in sequence at their C-terminal regulatory domains. By extending the 3' nucleotide sequence of the human gene (hSSTR2) we show highly conserved intron/exon boundaries suggesting that hSSTR2 is also capable of generating spliced variants. mRNA blots of rat tissues reveal 2 transcripts of 2.8 and 2.3 kb that are differentially expressed in brain regions and multiple peripheral organs. The 2.3 kb mRNA is preferentially expressed in pituitary tumor cells (AtT-20 mouse, GH3 rat, human prolactinoma, human somatotroph adenoma), but not in rat or human insulinoma cells. This transcript shows 4 fold induction by forskolin in AtT-20 cells suggesting cAMP dependent control of SSTR2 gene expression. The abundant expression of SSTR2 gene, the occurrence of 2 isoforms and evidence of extensive regulation at both gene and peptide levels, suggests that SSTR2 is the principal SST-14 selective subtype.

Amino Acid Sequence↗

PubMed1993

Heterologous processing of prosomatostatin in constitutive and regulated secretory pathways. Putative role of the endoproteases furin, PC1, and PC2.

Mammalian prosomatostatin (PSS) is cleaved at a dibasic Arg-Lys site to produce somatostatin-14 (SS-14) and at monobasic Arg and Lys sites to yield SS-28 and PSS(1-10) (antrin), respectively. Furin, PC1, and PC2 are three recently discovered mammalian endoproteases localized either to the constitutive (furin) or regulated (PC1, PC2) secretory pathways. In this study we have compared the heterologous processing of PSS in transiently transfected endocrine (AtT-20 pituitary) and nonendocrine (COS-7 monkey kidney, PC12 pheochromocytoma) tumor cells. We have correlated the efficiency of processing of PSS to SS-14, SS-28, and PSS(1-10) with (i) secretion through the constitutive or regulated pathways; (ii) endogenous expression of mRNA for furin, PC1, and PC2; and (iii) exogenous expression of PC1 and PC2 in cells that do not contain these enzymes in order to delineate the putative role of these enzymes in mediating PSS cleavage at dibasic and monobasic sites and to localize the proteolytic events to specific compartments of the secretory pathways. COS-7 and PC12 cells expressed only furin, secreted constitutively, and processed PSS preferentially at monobasic sites to SS-28 (40-43%) and antrin (27-29%). Processing, however, was inefficient as suggested by large amounts of unprocessed PSS. In contrast, AtT-20 cells showed regulated secretion, expressed all three endoproteases (with high levels of PC1), and processed PSS efficiently to mainly SS-14. PC1, but not PC2, exogenously coexpressed with PSS in COS-7 cells produced significant conversion to SS-14 but not SS-28. This study shows that PSS is capable of monobasic cleavage in the constitutive secretory pathway. Such processing could be mediated by a furin-like enzyme but is relatively inefficient. PC1 can effect dibasic cleavage of PSS whereas PC2 is without influence on PSS processing at least within the constitutive secretory pathway. Although monobasic and dibasic processing of PSS in COS-7 cells correlates with furin-like and PC1 activity, respectively, the relative inefficiency of such processing suggests that compartmentalization of proteolytic events in secretory vesicles or other more specific endoproteases may be required.

Animals↗

PubMed1993

The Psoriasis Disability Index--further analyses.

Clinicians have become increasingly aware of the important effects of psoriasis on patients' quality of life. As a result, several measures of the disabilities and handicaps associated with psoriasis have been developed. The Psoriasis Disability Index (PDI) has been shown to be sensitive to changes in the extent of lesions and to co-vary with the Sickness Impact Profile, a more general measure of the effects of disease on quality of life. In this study, patients with psoriasis and patients with other skin diseases completed the PDI. Although most items on the PDI were specific to psoriasis, some items applied to patients with urticaria, eczema, melanomas and other skin diseases. A factor analysis of the items indicated that the PDI contained two subscales, one concerning most aspects of everyday activities, the other concerning specific public situations such as the use of communal facilities.

Adult↗

PubMed1993

The reliability and validity of echocardiographic measurement of left ventricular mass index in hemodialysis patients.

We assessed the reliability and validity of a formula, based on echocardiographically derived parameters, to calculate left ventricular mass index (LVMI) in a group of 15 chronic hemodialysis patients. All patients had M-mode echocardiography before and after a hemodialysis session. Echocardiograms were interpreted by 2 observers blind to each other's measurements. Interobserver reliability for LVMI was high (r = 0.94, p < 0.0007). LVMI decreased in 11 of 15 patients during dialysis and increased in 4. The mean difference in LVMI between pre- and posthemodialysis was 26.2 +/- 15 g/m2 (p < 0.0001). End-diastolic diameter decreased from 53.5 +/- 5.9 to 49.5 +/- 7.5 mm (p = 0.0016). These data indicate that measurement of LVMI is highly reproducible in hemodialysis patients but that it changes significantly over the course of a hemodialysis session. Its use as an outcome measure in clinical trials in hemodialysis patients should be interpreted with caution.

Adult↗

PubMed1993

Cloning and expression of a human somatostatin-14-selective receptor variant (somatostatin receptor 4) located on chromosome 20.

Based on pharmacological, biochemical, and molecular criteria, multiple somatostatin receptor (SSTR) subtypes selective for somatostatin (SST)-14 and -28 have been postulated to exist in both the brain and periphery. We report here on the cloning and characterization of a human gene encoding a new member of the guanine nucleotide-binding protein-linked SSTR family, termed human (h)SSTR4. The 388-amino acid protein, with a predicted molecular mass of approximately 42 kDa, displays sequence similarity, particularly within putative transmembrane domains, with the recently cloned hSSTR1 (69%), hSSTR2 (56%), and hSSTR3 (58%). Membranes prepared from COS-7 cells transiently expressing the hSSTR4 gene bound 125I-[Leu8,D-Trp22,Tyr25]SST-28 in a saturable manner with high affinity (approximately 60 pM) and with a pharmacological profile and rank order of potency ([D-Trp8]SST-14 > SST-14 > SMS 201-995 > SST-28 > MK-678) indicative of a SST-14-selective receptor. Ki values for the inhibition of 125I-[Leu8,D-Trp22,Tyr25]SST-28 binding to the expressed receptor by these somatostatinergic peptides were 0.3, 1.1, 1.4, 2.2, and 6.5 nM, respectively. High affinity agonist binding to hSSTR4 was significantly reduced by GTP and pertussis toxin, indicating association of the expressed receptor with pertussis toxin-sensitive guanine nucleotide-binding proteins. Northern blot analysis revealed the presence of an SSTR4 mRNA species of approximately 4 kilobases in select regions of the monkey brain, including the hippocampus, hypothalamus, cortex, and striatum, with little or no receptor mRNA detected in either the olfactory tubercle, medulla, cerebellum, or amygdala. The SSTR4 gene maps to human chromosome 20. These findings document the existence of a novel human SSTR gene. Although the hSSTR4 displays an overall deduced amino acid homology of 86% with the recently reported rat homolog [Proc. Natl. Acad. Sci. USA 89:11151-11155 (1992)], the two gene products possess distinctive pharmacological profiles and affinities for the SST agonists SMS 201-995 and MK-678.

Amino Acid Sequence↗

PubMed1992

Vaccines against coxiellosis and Q fever. Development of a chloroform:methanol residue subunit of phase I Coxiella burnetti for the immunization of animals.

We have demonstrated the safety, immunogenicity, and efficacy of the WC and CMR vaccines in guinea pigs. Vaccination of guinea pigs with either WC or CMR protects animals against challenge with virulent C. burnetii. A total of 2 micrograms of either WC or CMR vaccine was a significant priming dose. A total of 20 micrograms gave complete protection against lethal challenge. Detection of antibodies to phase II cells by microaglutination, after vaccination with either WC or CMR and before lethal challenge, correlated with the ability of guinea pigs to mount a protective immune response. The PD50 values for WC and CMR vaccines, administered as a single dose, were 0.3 and 1.4 micrograms per animal, respectively. In contrast, the PD50 values for the WC and CMR vaccines, administered as two doses, were 0.83 and 0.72 micrograms per animal, respectively. Although the PD50 values for the two vaccines are similar, the CMR vaccine is preferred over the WC vaccine because it induces significantly fewer adverse reactions, and repeat injections can be given. Unvaccinated guinea pigs do not clear infectious microorganisms after challenge infection. Vaccination before challenge infection reduces the infectious load of C. burnetti in the blood and in various organs of the animals. When vaccinated animals were challenge infected and treated with rifampicin, the microorganisms were not eliminated from various organs. However, the combination of vaccination, challenge, and rifampicin treatment is effective in reducing the number of infectious microorganisms in some of these sites. We have demonstrated the safety and immunogenicity of the CMR vaccine in sheep and goats. Animals that were seropositive for one or more antigens developed significant levels of antibodies to alternate antigens, but no adverse reactions were observed at the site of s.c. injection of the CMR vaccine. This demonstrates that seropositive animals can be successfully immunized with this vaccine. These results also indicate that a long-term vaccination program using the CMR vaccine has the potential for producing animals with significant antibody titers to C. burnetii and perhaps lifelong immunity. The goal of a Q fever vaccination program is to produce immunized animals that are able to clear completely the infectious microorganisms. The appropriate vaccination schedule to render adult animals and their offspring "Q fever-free" should now be thoroughly investigated.

Animals↗

PubMed1992

A comparison of nonionic, low-osmolality radiocontrast agents with ionic, high-osmolality agents during cardiac catheterization.

BACKGROUND: Nonionic, low-osmolality radiocontrast agents are used frequently because they are believed to be safer than ionic, high-osmolality agents, but they are also more expensive. We conducted a randomized trial to compare the incidence of adverse events after the administration of ionic, high-osmolality and of non-ionic, low-osmolality radiocontrast agents during cardiac angiography. METHODS: We compared the need to treat patients for adverse reactions and the frequency and severity of specific hemodynamic, systemic, and symptomatic side effects in two groups of patients randomly assigned to receive either ionic, high-osmolality or nonionic, low-osmolality radiocontrast material, and also in 366 patients who could not be randomized. RESULTS: Treatment for adverse events was required in 213 of 737 patients who received high-osmolality contrast agents (29 percent) but in only 69 of 753 patients who received nonionic agents (9 percent) (95 percent confidence interval for the percent difference, 15.9 to 23.6 percent). Hemodynamic deterioration and symptoms also occurred more often in the high-osmolality group, as did severe or prolonged reactions (2.9 percent, as compared with 0.8 percent in the nonionic group; P = 0.035). The severe reactions were largely confined to patients with severe cardiac disease. Multivariate analysis showed that the presence of severe coronary disease and unstable angina were predictors of clinically important adverse reactions. If all the patients in our randomized trial had been given nonionic contrast material, the incremental cost per procedure would have been $89. CONCLUSIONS: Nonionic, low-osmolality contrast material is better tolerated during cardiac angiography than ionic, high-osmolality contrast material. Since cost constraints may prevent the universal use of nonionic contrast material, its selective use in patients with severe cardiac disease could be considered.

Contrast Media↗

PubMed1992

Effects of osseointegrated implants on psychological and social well-being: a literature review.

This article considers three research topics on the social and psychologic aspects of osseointegrated implants. First, the motivations of patients who enter therapy are described. Second, research studies on the psychologic effects of dental implants are critically examined. Although these studies provide consistent evidence in support of osseointegrated implants, there are many issues that make interpretation of results problematic. Finally, some suggestions for future research are made.

Dental Implantation, Endosseous↗

PubMed1992

Contrast nephropathy in patients with impaired renal function: high versus low osmolar media.

Prescription of low osmolar contrast to prevent nephrotoxicity in subjects with pre-existing renal impairment is costly and has not been clearly shown to be effective. We entered 249 subjects with a pre-contrast serum creatinine greater than 120 mumol/liter (1.35 mg/dl) having cardiac catheterization or intravenous contrast into a randomized controlled trial comparing high and low osmolar contrast. The outcome assessed was a rise in serum creatinine repeated 48 to 72 hours after contrast. A further 117 patients entered the non-randomized prospective arm of the study. In the randomized study the serum creatinine rose by at least 25% after contrast in 8 of 117 (6.8%) given high and in 5 of 132 (3.8%) given low osmolar contrast (P greater than 0.05, one-tailed 95% confidence interval for the difference 3 to 7.8%). More severe renal failure (greater than 50% increase in serum creatinine) after contrast was uncommon (3.4% with high and 1.5% with low osmolar contrast). A rise in serum creatinine after contrast was significantly associated with the severity of the pre-contrast renal impairment and the presence of diabetes mellitus, but not with type of contrast. Diabetics with a serum creatinine greater than 200 mumol/liter (2.25 mg/dl) pre-contrast had a highest risk of deterioration in renal function after contrast. We conclude that in patients with pre-existing renal impairment the incidence of contrast nephropathy was not significantly different comparing high osmolar and nonionic contrast. The potential benefit of nonionic contrast in moderate renal impairment is likely to be small, but trials in diabetics with severe renal impairment should be undertaken urgently.

Aged↗

PubMed1991

Reactions of medical students affected by a major disaster.

This report describes the concerns and reactions of medical students who were affected by a major disaster at a football game in Sheffield in 1989. Some reactions were related to their stage of training, especially their feelings of guilt, doubts about their competence, and concern that they would not be able to cope with the stresses of doctoring. Relationships with fellow students were also problematic. Four months after the disaster, two students were still experiencing considerable distress. Staff can ameliorate such effects by providing formal teaching about posttraumatic stress disorder and by being prepared to offer support.

Adaptation, Psychological↗

PubMed1991

Biochemical and genetic characterization of a rapid-development strain in Dictyostelium discoideum.

We have examined the rates of development of six wild-type and rapid-development strains of Dictyostelium discoideum. Strains NC4 and HU1231, a derivative of V12, have very similar developmental profiles. In comparison to these two strains, amoebae of the rapid-development strain HT100 reach the aggregation stage about 6 h earlier. Also, intracellular cAMP levels in HT100 increase precociously during early development. Postaggregative morphogenesis of HT100 proceeds at the same rate as NC4 and HU1231. In addition we have assessed the progress of development by RNA hybridization blotting. The appearance in HT100 of mRNAs associated with aggregation is advanced by 6 h while the appearance of early gene products is not affected appreciably. These data suggest that HT100 differs from strains NC4 and HU1231 primarily in the process of aggregation. We have partially characterized the genetic background of strain HT100. Mating and cell fusion analyses suggest that HT100 is a derivative of V12. We constructed a growth-temperature-sensitive derivative of HT100, and fused it with HU1231 cells. The resulting diploids develop at the same rate as HT100, suggesting that the rapid-development phenotype in HT100 is dominant.

Animals↗

PubMed1991

Controlled longitudinal study on the psychological effects of osseointegrated dental implants.

Forty-seven patients participated in a longitudinal study on the psychological effects of the Brånemark implant technique. They were asked to complete questionnaires measuring their psychological well-being and symptom level on two occasions. The first occasion was shortly after the initial prosthetic assessment. Although 29 patients were subsequently accepted for implant treatment, 18 were found to be unsuitable at the later surgical assessment. Both groups of patients were again given the questionnaires approximately 2 years later. The implants were associated with a clinically significant improvement on measures of symptoms and psychological distress, but there was no change in self-esteem. By contrast, the only change in the untreated comparison group was that their level of distress had risen.

Adult↗