Fine needle aspiration in infected hip replacements

Ninety painful prosthetic hips from 88 consecutive patients underwent fine needle aspiration and the results compared with clinical progress, operative findings and culture. Fourteen of the 15 cases proven to be infected at operation were correctly identified by fine-needle aspiration. The one hip with a false negative aspirate had an arthrogram which showed a cavity suggesting infection. There were three false positive aspirates. One grew a different organism at surgery from the original aspirate. The other two had no growth on surgical culture. Both had had pre-operative antibiotics. Eleven cultures of doubtful significance were repeated or regarded as negative and the patients carefully followed-up. One repeat culture confirmed infection emphasizing the importance of repeating doubtful aspirates. The sensitivity of aspiration is 93%, specificity is 96%. The accuracy is 95% confirming that aspiration is a simple and reliable method of diagnosing infection in hip prostheses.

Orogastric magnet removal of ingested disc batteries

Ingestion of disc batteries by infants and small children is an increasing problem. Batteries that remain in the stomach can corrode and damage mucosa and/or produce poisoning. Between 1989 and 1992, 37 children who had swallowed a total of 46 disc batteries presented to the Royal Hospital for Sick Children, Edinburgh, and were referred for battery removal by use of an orogastric magnet under fluoroscopy. Thirty-nine batteries were removed successfully (without anesthesia) from 32 children, using a magnet attached to an orogastric tube. In three cases the battery had passed into the small bowel. In one case, magnet extraction failed, but the two batteries the child had ingested subsequently passed into the small bowel. In two cases the patients refused to swallow the tube. In one of these cases the battery was removed successfully by the magnet, with the patient under general anesthesia; in the other it passed spontaneously into the small bowel. The authors conclude that orogastric magnet removal is a minimally invasive, well-tolerated method of removing ingested disc batteries.

A PCR-based genetic map for human chromosome 3

Oligonucleotide primers for 125 simple sequence repeat microsatellite-based genetic markers have been assayed by polymerase chain reaction (PCR) in the CEPH reference family panel. These microsatellites include 101 dinucleotide repeats as well as 24 new tetranucleotide repeats. The average heterozygosity of this marker set was 72.4%. Genetic data were analyzed with the genetic mapping package LINKAGE. A subset of these microsatellite markers define a set of 56 uniquely ordered loci (> 1000:1 against local inversion) that span 271 cM. Sixty-seven additional loci were tightly linked to markers on the uniquely ordered map, but could not be ordered with such high precision. These markers were positioned by CMAP into confidence intervals. One hundred thirteen of the microsatellite markers were also tested on a chromosome 3 framework somatic cell hybrid panel that divides this chromosome into 23 cytogenetically defined regions, integrating the genetic and physical maps of this chromosome. The high density, high heterozygosity, and PCR format of this genetically and physically mapped set of markers will accelerate the mapping and positional cloning of new chromosome 3 genes.

Duplex ultrasound surveillance of infrainguinal bypass grafts: auditing the process

The effectiveness of an infrainguinal bypass graft surveillance programme using duplex scanning was assessed over a 2-year period. Of 220 infrainguinal bypass grafts (123 vein and 97 PTFE grafts; 114 to the above knee level, 94 below knee and 12 distal to popliteal artery) in 203 patients, 208 (94.5%) were available for follow-up surveillance. The protocol called for duplex scans at 6 weeks, 3, 6, 9 and 12 months. Fifty-seven grafts (27%) were found to have a V1/V2 ratio equal to or greater than 1.5 and in this group 25 grafts occluded. The median time between primary operation and positive duplex finding was 4 months. Thirty-nine grafts failed during follow-up (at time of analysis median follow-up was 12 months [range 2-83 months]). There were 18 interventions resulting from surveillance-detected stenoses. The median time between positive duplex finding and further investigation was 2 months. Further, there were significant differences in the site of abnormal findings between ePTFE and vein grafts. The value of a surveillance programme may be reduced if there are low rates of intervention and/or excessive delays in intervention following the demonstration of graft-related stenoses. Surveillance programmes and subsequent interventions need to be audited.

A radiation hybrid map of the BRCA1 region

A locus on chromosome 17q, designated "BRCA1," has been identified as a predisposition gene for breast cancer. A panel of chromosome 17-specific radiation-reduced somatic cell hybrid clones has been assembled for high-resolution mapping of chromosome 17. A series of 35 markers, known to span the BRCA1 locus, were tested against this hybrid panel by PCR assays. Statistical analysis of these data yields a BRCA1 radiation hybrid map at a density sufficient to initiate YAC cloning and pulsed-field gel electrophoretic mapping of the candidate region. In addition, many of the markers reveal genetic polymorphisms and may be tested in breast cancer families and in loss-of-heterozygosity studies of sporadic breast cancers to better define the BRCA1 gene candidate region.

Solid state NMR imaging of irreducible water in reservoir cores for spatially resolved pore surface relaxation estimation

The use of solid state NMR imaging in reservoir core applications has long been proposed. This paper describes the use of a simple, robust technique in the first such application. One- and two-dimensional images of the irreducible brine in a sandstone and carbonate reservoir core are demonstrated. The applicability of solid state NMR imaging to pore surface relaxation estimation is discussed.

Pneumatic reduction of intussusception: clinical experience and factors affecting outcome

Between 1987 and 1992, 54 patients (32 male, 22 female) underwent 62 attempts at pneumatic reduction of intussusception. The mean age at presentation was 12.5 months (range 2.5 to 4 years 4 months). A retrospective review of all cases was performed to identify success rate and factors affecting it. Successful reduction was achieved in 46 cases (74%). One case was complicated by perforation and four cases (7%) by early recurrence. Patients with failed pneumatic reduction were more likely than those with successful reduction to have: (1) long duration of symptoms; (2) bleeding per rectum; (3) small bowel obstruction. Among the 16 cases of failed reduction, surgical findings were: five cases of ileo-ileo-colic intussusception, one with ileo-ileal, one with perforated ischaemic colon during air enema and one whose intussusception was found to be reduced at surgery. Three patients had lead points: Meckel's diverticula in two and a pinworm in one. Resection was required in three cases for non-viable bowel and in another two for the Meckel's diverticula. Pneumatic reduction of intussusception offers a high success rate with few complications. Performing an air enema earlier in the course of the disease may increase the chance of successful reduction.

Distribution of the recombinant coagulation factor 125I-rFVIIa in rats

Recombinant human factor VIIa (rFVIIa; NovoSeven) is a two-chain activated clotting factor that is used in the treatment of haemophilia. The distribution of radioactivity in male and pregnant and non-pregnant female rats has been examined by whole-body autoradiography (WBA) after single intravenous doses of 125I-radiolabelled rFVIIa at a dosage level of ca. 0.1 mg/kg. Concentrations of radioactivity were highest in the blood and the highly perfused major thoracic and visceral organs and gonads. This distribution of radioactivity was generally similar in pregnant and non-pregnant females, and although radioactivity was concentrated in the foetal thyroid, it was present in other foetal tissues only at trace levels. Radioactivity in thyroid, urinary bladder and gastrointestinal tract of all rats was apparently associated with detached 125I-iodide. At early sacrifice times (up to 2 h), radioactivity was present in the bone marrow, but at later times (6-24 h) it was apparently associated with the mineralised bone structures. The quantitative distribution of total and trichloroacetic acid precipitable radioactivity in the tissues of rats also was studied after single intravenous doses of 125I-rFVIIa and 125I-rFVII, the non-activated single chain precursor of FVIIa, which is normally present in the circulation. These studies confirmed the WBA findings and showed that the tissue distribution of 125I-rFVII and 125I-rFVIIa was similar, indicating that the distribution of rFVIIa during therapy would be similar to that produced from endogenous FVII as a physiological response to vascular injury.

The effects of supravalvular aortic stenosis on realistic three-dimensional left ventricular blood ejection

The effect of supravalvular aortic stenosis on cardiac left ventricular ejection was determined from a realistic left ventricle (LV) model built from the profile of a diastolic dog LV. The ejection fraction was considered to be 75% of the diastolic volume. The maximum blood ejection velocities and ventricular pressure occurred at the start of the diastolic flow since the ventricular walls moved the fastest at this point. Going from a healthy non-stenotic LV to one with 64% stenosis increased the maximum ejection velocity from 117 cm/sec to 269 cm/sec, and the maximum relative pressure increased from 10,420 dynes/cm2 to 33,550 dynes/cm2 (7.82 to 25.16 mm Hg). The supravalvular stenotic aorta showed major flow disturbances as the degree of stenosis increased. The computational technique using a realistic model gives predictions in general agreement with observed experimental results, and allows a complex determination of the three-dimensional flow patterns.

Pharmacokinetics of recombinant factor VIIa in the rat--a comparison of bio-, immuno- and isotope assays

Recombinant human factor VIIa (rFVIIa) is an activated coagulation factor for intravenous use as a haemostatic agent in haemophiliacs who generate antibodies against factor VIII or IX. Plasma kinetic studies are important for the understanding of the action of rFVIIa which is exerted in the vascular compartment of the body, more specifically on the vessel walls at the site of injury. In the present study, rats were dosed 100 or 500 micrograms/kg 125I-rFVIIa i.v., without any side effects being observed, and the plasma profile of rFVIIa was studied by 3 different assays that were shown to correlate well at early times post-dose: trichloroacetic acid (TCA)-precipitable drug-related radioactivity, rFVIIa antigen determination by ELISA technique, and the assay of clot activity which is the only clinically applicable assay. The plasma concentration curve could be resolved into 1-3 exponentials, depending on the FVIIa detection principle that was employed. Initially, there was a short (ca. 10 min) phase of increasing concentrations before the attainment of Cmax. This was followed by a plasma recovery (Cmax x plasma volume/dose) in the vicinity of one half of the administered dose. The initial volume of distribution (V1) corresponded to the vascular compartment whereas the volume of distribution at steady state (Vss) was somewhat larger. Whole body clearance (CL-B) of rFVIIa was approx. 1 ml/min per kg, and mean residence time (MRT) and the half-life assumed to be associated with the loss of biological activity was approx. 1 h and 20-45 min, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between pharmacokinetics and pharmacodynamics of tinzaparin (logiparin), a low molecular weight heparin, in dogs

1. Pharmacodynamic models relating the plasma concentrations (C) of radioactive heparin material to anticoagulant effect (E) have been investigated after single i.v. and s.c. doses of 3H-tinzaparin (1 and 4 mg/kg), a radiolabelled low molecular weight heparin, to six dogs. 2. A counterclockwise hysteresis, characterizing the C versus E relationship, was observed in all animals after s.c., but not i.v., doses indicating a possible delay (lag-time) in the systemic availability of pharmacologically-active heparin material following extravascular administration. A constant (Ke) was introduced into the model to account for this hysteresis. 3. At high plasma concentrations of radioactivity (> 10 micrograms/ml), E was related to C by a sum of two sigmoid Emax models, whereas, at lower concentrations, this reduced to the well-known sigmoid Emax model. It was proposed that tinzaparin activates two 'receptors' having different affinities for the drug. The values of EC50 associated with the activation of a single 'receptor' and of a proposed additional 'receptor' were 3 and 13 micrograms/ml of heparin material, respectively. 4. Heparin material was predominantly eliminated by renal excretion and underwent widespread tissue distribution. After s.c. administration, input of heparin material into systemic plasma was complete within 12 h post-dose, and the absorption process was characterized by a bi-exponential function. 5. We conclude that sigmoid Emax models adequately describe the C versus E relationship after s.c. and i.v. doses of 3H-tinzaparin in dogs and that the interindividual variation of the pharmacodynamic parameters derived from this model was relatively small.

Comparison of response to injury in organ culture of human saphenous vein and internal mammary artery

Autologous saphenous vein grafts, unlike internal mammary artery grafts, suffer many late occlusions as a result of excessive proliferation of vascular smooth muscle cells and the superimposition of atheroma on the resulting thickened intima. We investigated the possible basis of this difference using organ cultures. Internal mammary artery segments and freshly isolated and surgically prepared saphenous vein segments were obtained from patients undergoing coronary artery bypass grafting. Internal mammary artery and freshly isolated vein segments showed a high degree of endothelial coverage and medial cell viability that were maintained during culture. Surgically prepared veins showed partial endothelial denudation and medial cell injury, both of which tended to be reversed during culture. Neointimal thickening was greater in surgically prepared vein (72 +/- 13 microns; n = 11) than in freshly isolated vein (44 +/- 8 microns; n = 10) or internal mammary artery (34 +/- 4 microns; n = 13) segments. The occurrence of proliferating cells in the medial layer was also significantly greater in surgically prepared vein (2.8 +/- 1.0/mm; n = 11) than in freshly isolated vein (0.8 +/- 0.3/mm; n = 9) or internal mammary artery (0.6 +/- 0.3/mm; n = 10) segments. The data show that although the smooth muscle proliferation was similar in undamaged saphenous vein and internal mammary artery, it was significantly greater in damaged vein. This implies that the greater intimal proliferation seen in saphenous vein grafts may arise not from intrinsic differences in arterial and venous smooth muscle cells but from a greater susceptibility to injury.

Sex differences in lung-cancer risk associated with cigarette smoking

The importance of cigarette smoking as a risk factor for specific histologic types of lung cancer in men and women has been examined in a case-control analysis of data from the Cancer Surveillance Program of Orange County, a population-based registry. Smoking habits were abstracted from medical records for 1153 men and 833 women diagnosed with primary lung cancer in 1984-1986 and 1851 men and 1656 women aged 30 or older diagnosed with cancers not associated with smoking. Ninety-six percent of men and 89% of women with lung cancer were current or former cigarette smokers, as compared with 55% of men and 34% of women with other cancers. The age and ethnicity-adjusted odds ratios (OR) for ever-smoking were 19.7 for men and 15.0 for women. Men and women who smoked 2 or more packs per day experienced nearly equal risks. Comparison of the most common cell types showed that women smokers had equal or lower ORs for squamous-cell carcinoma and adenocarcinoma, but higher OR for small-cell carcinoma, as compared with men smokers. While the smoking-associated OR were equal for small-cell and squamous-cell carcinomas in men, the OR for women were significantly higher for small-cell carcinoma than for squamous-cell carcinoma.

Toxicity of paracetamol in cultured chick hepatocytes treated with methotrexate

Cultured chick hepatocytes were used to investigate the hepatotoxicity of methotrexate alone and in combination with paracetamol. Treatment with methotrexate alone at concentrations as high as 1 mg/ml resulted in no toxicity in cultured chick hepatocytes, as indicated by no detachment of cells and no effect on protein synthesis or on release of the intracellular enzyme lactate dehydrogenase. However, treatment with methotrexate alone resulted in a 30% decrease in reduced glutathione levels. Combined treatment with methotrexate and paracetamol was toxic, but only in cells preinduced for cytochrome P450 1A by treatment with beta-naphthoflavone. Under these conditions, methotrexate lowered the threshold concentration of paracetamol at which toxicity was observed. This methotrexate-mediated increase in paracetamol toxicity was associated with decreased formation of the glucuronide, sulfate and thiol metabolites of paracetamol and with increased covalent binding of radiolabeled paracetamol to macromolecules. In cells pretreated with beta-naphthoflavone, additional treatment with either methotrexate or buthionine sulfoximine, an inhibitor of glutathione synthesis, together with paracetamol, was associated with decreased restoration of glutathione levels. These results suggest that methotrexate increased paracetamol toxicity by decreasing the amount of glutathione available for conjugation with reactive metabolites of paracetamol.

Transformation: nursing education and cultural diversity

Teaching is the transformation of ideas and content into representations that are appropriate for particular students. The teacher moves from a personal understanding of an idea to its being comprehended by the students. Teachers change knowing into telling, and students change that telling into doing and caring.

Resistance training for rehabilitation of disability secondary to low back pain

Low back pain (LBP) is the number-one cause of disability of individuals under 40 years of age. The cost to society both in medical expense and loss of productivity is billions of dollars annually.1,2 The etiology of both acute and more persistent LBP is multifactorial, but torso weakness is considered a contributing factor. It is well documented that improved strength, as well as general conditioning, improve the odds of successful return to work.2-7 For these reasons, resistance training is often prescribed for the prevention and rehabilitation of disability secondary to LBP.The purpose of this article is to review current literature regarding resistance training for rehabilitation of LBP. Trunk strengthening will be reviewed in more detail and general principles for extremity resistance training will be reviewed as well.

Intimal proliferation in an organ culture of human internal mammary artery

OBJECTIVE

Intimal smooth muscle cell proliferation is an early feature of atherosclerosis. Its progression is difficult to monitor in humans and previous studies have mostly relied on necropsy material. The aim of this study was therefore to establish whether intimal proliferation occurred in an organ culture of human internal mammary artery.

METHODS

Segments of freshly isolated internal mammary artery were maintained din standard tissue culture medium containing 30% calf serum for 14 d. Tissue viability (measured by ATP concentration) was maintained during processing and throughout the culture period [211(SEM 28) nmol ATP.g-1 wet weight on d 1 v 208(27) on d 14].

RESULTS

Histological transverse sections of cultured internal mammary artery showed the development of a neointima containing smooth muscle cells identified by immunocytochemistry for alpha actin. Pulse labelling of cultures with [3H]-thymidine showed proliferating cells predominantly in a neointimal layer with few dividing cells in the media. Cultured de-endothelialized vessels showed less neointimal thickening than cultured freshly isolated vessels [16(3) v 36(5) microns, p < 0.0025] as well as a reduced number of dividing cells per mm of neointimal length [3.1(0.6) v 5.5(1.1), p < 0.05].

CONCLUSIONS

Intimal proliferation occurred in organ culture of internal mammary artery. There is evidence for a factor derived from the endothelium, which may be important in the development of intimal proliferation.

Plasmodium falciparum: diversity of isolates from Malawi in their cytoadherence to melanoma cells and monocytes in vitro

We observed considerable diversity in the cytoadherence of Plasmodium falciparum isolates from Malawi to melanoma cells, U937 cells and human peripheral monocytes. Each isolate exhibited a unique cytoadherence profile for the three human cell types. These isolates generally adhered well to U937 cells and fresh monocytes, moderately to melanoma cells and poorly to TE 671, MIA-Pa-Ca, WI 38, PLC/PRF/5 and HeLa cells. An antimalarial immunoglobulin pool inhibited binding to melanoma cells by 50% or more and to U937 cells by 25% or less. There was no correlation between in vitro cytoadherence to the three cells and clinical disease. These results suggest that malarial adherence ligands exposed on the surface of infected erythrocytes vary from one isolate to another.

A comparison of the high buoyant density proteoglycans isolated from the intervertebral discs of chondrodystrophoid and non-chondrodystrophoid dogs

Groups of purebred beagles and greyhounds of similar ages (1.5-2.5 years) were used for the study. Intervertebral disc proteoglycans (PGs) were radiolabelled in vivo (with [35SO4(2-)], 24 hours and 60 days prior to euthanasia, when lumbar discs were dissected into nucleus pulposus (NP) and annulus fibrosus (AF). Aliquots of each disc region were separately analysed for total PG content as hexuronate. The remaining tissue was subjected to extraction with 4.0 M GuHCl. High buoyant density PGs were isolated from these extracts by CsCl density gradient ultracentrifugation. The hydrodynamic size and aggregatability of the 24-hour, 60-day-old, and resident PG populations were determined by Sepharose CL2B chromatography in the presence or absence of excess hyaluronic acid. While the hydrodynamic sizes of the newly synthesized (24-hour) disc PG preparations appeared to be similar, the 60-day-old greyhound disc PGs were found to be larger than the corresponding beagle disc PG populations. However, the keratan sulphate-core protein complexes prepared by chondroitinase ABC digestion of the newly synthesized (24 hour) disc PGs showed that the greyhound disc preparations were also larger than those from beagle discs. Approximately 80% of the newly synthesized PGs from beagle and greyhound discs were capable of aggregating with hyaluronic acid, however, this was reduced to 55% for the 60 day-old PGs in NP and AF and even less for the resident PG populations (as determined by hexuronate analysis). Significantly, PG aggregation was lower in the greyhound NP and AF preparations than in the corresponding PGs isolated from the beagle disc.(ABSTRACT TRUNCATED AT 250 WORDS)