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Biomedical subjects

N Price

Publications and source records attributed to N Price.

At least 37 records · Page 2Linked to original sources
PubMed2000

Safety and efficacy of India ink and indocyanine green as colonic tattooing agents.

BACKGROUND: Controversy exists concerning the safety and efficacy of colonic tattooing for the intraoperative identification of polypectomy sites. The purpose of this study was to determine (1) the concentrations of India ink and indocyanine green that resulted in high-visibility tattoos without significant tissue inflammation and (2) the India ink injection volume that produces best visibility at colonoscopy, laparoscopy, and laparotomy. METHODS: Twenty-two New Zealand white rabbits (2 kg) were anesthetized and injected with India ink (undiluted 1:10, 1:50, 1:100, 1:1000, 1:10,000) and indocyanine green as an undiluted, concentrated formulation (25 mL/2 mL solvent) or in a diluted form (25 mg/5 mL solvent) at various concentrations (1:10, 1:50, 1:100). Tuberculin syringes were used to create a 0.1 mL serosal bleb at two injection sites 2 cm apart. Laparotomy was repeated at days 1, 3, and 7 after injection. Additionally, 16 rabbits were injected with India ink at laparotomy and re-explored at 1 and 5 months. Twelve mongrel dogs (20 kg) were injected with 1.0 mL volumes. Re-exploration by colonoscopy, laparoscopy, and laparotomy was done at 7 days and 1 month. Tattoo visibility at re-exploration in both animal models was graded on a scale (0 = agent not seen, 1 = seen with difficulty, 2 = easily seen). Histology in the rabbit was judged by degrees of inflammation (0 = no inflammation, 2 = mild inflammation, 4 = moderate inflammation, 6 = severe inflammation). RESULTS: The concentrated indocyanine green solution was easily visible only on day 1 in the rabbit. Injections of both concentrated and diluted indocyanine green caused mucosal ulceration and moderate to severe inflammation. India ink studied at 7 days, 1 month, and 5 months after injection in the rabbit model was visible at all concentrations. The undiluted and 1:10 concentrations were easily seen and showed evidence of mucosal ulceration. Tattoos produced with all other India ink concentrations were visible without gross inflammation. India ink was also studied at 7 days and 1 month in dogs. The tattoo with the 1:100 concentration at 0.5 mL was seen consistently at colonoscopy, laparoscopy, and laparotomy with only a mild submucosal reaction at 7 days. The tattoos produced with the 1:100 and 1:1000 concentrations at 0.5 mL and 1.0 mL injection volumes were easily seen by all methods of intraabdominal visualization at 1 month with similar histology. CONCLUSION: Indocyanine green was an ineffective colonic tattooing agent. India ink was an effective colonic tattooing agent. Dilute concentrations that caused little to no inflammation could be visualized at 7 days and 1 month in rabbits and dogs and at 5 months in rabbits. India ink, at appropriated concentrations, appears to be a safe short- and long-term colonic tattooing agent.

Animals↗
PubMed1998

Dangers of delay of initiation of either thrombolysis or primary angioplasty in acute myocardial infarction with increasing use of primary angioplasty.

We observed treatment delays and suboptimal outcomes when beginning to treat patients with acute myocardial infarction (AMI) with primary angioplasty. Of the 37 patients treated during a 12-month period, 12 (32%) required either emergency bypass surgery or died. Delayed time intervals to balloon reperfusion (mean 134 minutes) probably contributed to these adverse outcomes, with hemodynamic instability requiring pressors or intra-aortic balloon pumping in 15 patients, 12 (75%) before the first balloon inflation. Eleven of the 12 patients with significant adverse outcomes required such intervention. As angioplasty use increased, time intervals to thrombolysis in those not treated with angioplasty increased from an average of 29 minutes (53% treated less than the national standard of 30 minutes) to 39 minutes (32% treated <30 minutes, p <0.001). During the last 2 months of the study period, the time intervals had increased to 48 minutes (14% treated <30 minutes, p <0.0001). There was no change in thrombolytic time intervals at a local community hospital that did not offer primary angioplasty. Emergency Department physician confusion about the best therapy (angioplasty or thrombolysis) was documented in the medical records in 42% of cases (53 of 127). Confusion regarding therapy of AMI led to unacceptable delays in the administration of thrombolytic agents and probably contributed to the adverse outcomes in patients receiving primary angioplasty.

Aged↗
PubMed1998

Expression of an embryonic fibronectin splicing variant in human masseter muscle.

Fibronectin is an extracellular matrix protein that is a key constituent of all skeletal muscles. Its deposition increases in a number of pathological conditions, including some muscular dystrophies in which a progressive increase in lower-face height is often noted. It has been shown in other organ systems that increased deposition of fibronectin is associated with changes in the expression of differentially spliced isoforms of the molecule. This investigation documents the expression of mRNA coding for fibronectin and its splicing variants, EIIIA and EIIIB, in biopsies of masseter muscle from normal and long-face patients, using reverse transcriptase-polymerase chain reaction. Expression was compared with that occurring in anatomically and embryologically differing somatic skeletal muscle. Masseter expressed fibronectin mRNA containing the EIIIA but not the EIIIB splicing variant. Conversely, somatic skeletal muscle expressed neither the EIIIA nor EIIIB variants. There were no differences between expression of fibronectin containing the EIIIA splicing variants in masseter from normal and long faces. These results suggest that variations in fibronectin expression reflect the differing functional demands of muscles from different anatomical locations and indicate that jaw and somatic muscle belong to different allotypes.

Base Sequence↗
PubMed1998

Do intraocular angiotensin II levels, plasma prothrombotic factors and endothelial dysfunction contribute to proliferative diabetic retinopathy?

PURPOSE: To investigate whether diabetic retinopathy (DR) is associated with abnormalities in: (i) aqueous humour Angiotensin I (Ang I) and Angiotensin II (Ang II) levels; and (ii) plasma Ang I, soluble P-selectin, lipoprotein (a) (Lp(a)), endothelial markers and haemorheological abnormalities. METHODS: Cross-sectional study of diabetic patients and healthy controls undergoing cataract surgery. RESULTS: 21 diabetic patients (12 males; mean age 67.0 years) were studied. Plasma levels of Ang II were lower in diabetics compared with controls (p<0.05). There were no differences in mean aqueous Ang I and Ang II levels in diabetics with or without proliferative DR compared with controls. Mean systolic blood pressure was higher in Group 1 patients (p=0.02). Patients with DR also demonstrated high Lp (a) and abnormal haemorheological factors (fibrinogen, white cell count). CONCLUSION: Ang I and Ang II do not significantly contribute to the pathogenesis of DR. Patients with DR also had abnormal Lp (a) and haemorheological factors. The role of hypertension in the pathogenesis of DR needs further evaluation.

Aged↗
PubMed1997

Human osteoblast-like cells (MG63) proliferate on a bioactive glass surface.

Bioglass, a resorbable glass, previously has been evaluated as a bone graft substitute using cells of animal origin. Limited information is available on its effect on human cells. The objective of this study was to test the hypothesis that Bioglass supports viability and proliferation of human bone cells. As a prototype of human bone cells, the osteoblast cell line MG63 was used and propagated on Bioglass disks. MG63 cells also were seeded onto disks made of titanium (Ti-6Al-4V) and of cobalt chrome (Co-Cr-Mo) alloys. The number of viable cells recovered was similar for Bioglass, titanium, and polystyrene control surfaces. Significantly fewer cells were recovered from CoCr (P < 0.05) compared to Bioglass, Ti-6 Al-4v, and polystyrene surfaces. The proportion of cells undergoing DNA synthesis, estimated by thymidine uptake, was significantly greater on Bioglass and titanium surfaces (P < 0.05) than on the CoCr surface. There were detectable differences in cell morphology on these biomaterials. Functional capacity was tested by assay of osteocalcin production and no differences were detectable among the different biomaterials. This study supports the hypothesis that 45S5 Bioglass provides a favorable environment for human osteoblast proliferation and function. Bioglass may have clinical potential as a bone graft substitute, a bioactive grout, or an implant coating for promoting bony ingrowth in uncemented prostheses.

Alloys↗
PubMed1996

Clinical audit in the National Health Service: fact or fiction?

It is increasingly recognized that the repeated rhetorical emphasis from 1989 to date on achieving measurable benefits to patients from audit, in the face of inattention to the development of methodologies with which to realize such benefits in operational practice, has represented a serious deficiency in strategic planning and direction and a consequent failure to establish functional clinical audit within the NHS. A grand revision of strategy is therefore necessary, and this should begin with the development of a research-based method of audit, the training of clinicians and audit support staff in its use and a subsequent trial of its effectiveness prior to its implementation within the NHS. Only then will measurable improvements become possible, value for money be assured and clinicians' attitudes to audit change.

Attitude of Health Personnel↗
PubMed1996

The Total Health Care Audit System: a systematic methodology for clinical practice evaluation and development in NHS provider organizations.

Writing in Medical Education in 1982, Fowkes (1982) noted the lack of general agreement within the medical profession on methods of audit, a deficiency previously articulated by Shaw (1980) and later emphasized by McIntyre (1985). More recently, a study by Black & Thompson (1993) of consultant and junior medical staff in four London district general hospitals revealed that 'many doctors did not understand how to undertake audit', and major research by both Hopkins (1993, 1994) and Buttery et al. (1994) described a multiplicity of methodological deficiencies in the general approaches to audit adopted by clinicians since the promulgation of the White Paper definition in 1989. Soundness of methodological approach is fundamental to securing the success of clinical audit within Provider organizations and is thus central to the generation of measurable improvements in the quality of clinical care being delivered to patients. It is therefore disturbing that methodological deficiencies may still be observed in general approaches to audit (Buttery et al. 1994), with no author yet recommending a formal system for critical inquiry into clinical practice. It was the recognition of the unsatisfactory nature of this situation which led us to develop a system aimed at assessing, in a critical fashion, the quality of the totality of care dispensed within NHS provider organizations. The system is presented here for the first time.

Algorithms↗
PubMed1996

The changing value of children among the Kikuyu of Central Province, Kenya.

"This article describes and analyses recent changes in the social institutions and cultural practices which have traditionally supported high fertility among the Kikuyu of Central Province, Kenya, and assesses the extent to which such institutions and practices retain their significance in the context of the changing value of children. The material and symbolic value of children to the Kikuyu is analysed, using methods and concepts derived from social anthropology.... After briefly profiling each of the communities of study, the article is organised around three themes which correspond to the key social institutions that shape fertility motives: marriage, kinship and religion. A fourth theme which runs throughout the article is the changing strategic role played by these same institutions in regulating or enhancing fertility." (SUMMARY IN FRE)

Africa↗
PubMed1995

The highly acidic C-terminal region of the yeast initiation factor subunit 2 alpha (eIF-2 alpha) contains casein kinase phosphorylation sites and is essential for maintaining normal regulation of GCN4.

Regulation of the effective activity of eukaryotic initiation factor 2 (eIF-2) in protein synthesis is known to involve phosphorylation of its alpha subunit. Two mammalian enzymes, the haem-controlled repressor (HCR) and the double-stranded RNA-activated inhibitor (dsI), phosphorylate Ser-51 of the alpha subunit, thereby inhibiting the exchange of bound nucleotides on, and thus the recycling of, eIF-2. In Saccharomyces cerevisiae, the equivalent serine seems to be phosphorylated by the GCN2 protein kinase, which is activated by amino acid starvation. However, in the present paper we show that this is not the only site of phosphorylation in yeast eIF-2 alpha. We report the preparation of recombinant yeast eIF-2 alpha from Escherichia coli and its use in in vitro phosphorylation studies. Mammalian HCR and dsI are shown to phosphorylate specifically Ser-51 of yeast eIF-2 alpha, whereas extracts from yeast cells do not. Instead, at least one of three serine residue in the acidic C-terminal region of this protein is phosphorylated by fractions of yeast possessing casein kinase activities 1 and 2. A triple Ser-->Ala mutant form of yeast eIF-2 alpha was found to be no longer phosphorylated by either of the yeast (or mammalian) casein kinase activities in vitro. Isoelectric focusing of yeast extracts confirmed that the mutated sites normally act as sites of phosphorylation in vivo. The same mutant was used to show that the three sites have no essential function under normal physiological conditions in yeast. In contrast, deletion of the 13 amino acid long C-terminal region of eIF-2 alpha, including the three phosphorylation sites, led to derepression of GCN4 in vivo. Thus removal of the short, highly acidic C-terminal region of eIF-2 alpha has the same regulatory effect on translational (re)initiation as phosphorylation of the Ser-51 residue of the wild-type protein. This result provides new insight into the role of eIF-2 alpha activity in the regulation of translational (re-) initiation.

Amino Acid Sequence↗
PubMed1995

Epidural anaesthesia and urinary dysfunction: the risks in total hip replacement.

Epidural anaesthesia in total hip replacement is an established and safe practice. It may be used alone or in combination with general anaesthesia for analgesia. Urethral catheterization in the perioperative period is known to greatly increase the complication of deep sepsis following total hip replacement. We assessed the effect on the incidence of urinary catheterization of using bupivocaine epidural anaesthesia in addition to general anaesthesia in total hip replacement. A prospective study was made of 113 total hip replacements. The incidence of catheterization in male patients who received an epidural was 67% compared to only 12% who had no epidural [P = 0.001]. In women the corresponding rates were 30% and 23%. We conclude that in men the use of supplementary epidural anaesthesia with bupivocaine is associated with a worrying increased need for urinary catheterization. This must be balanced against the claimed benefits of this form of anaesthesia.

Adult↗