Use of X-rays in family practice A multicentre study

Practising physicians, faced with pressure to control healthcare costs, are increasingly being asked to incorporate considerationsof cost into their decisions regarding the care they offer theirpatients. Accordingly, it is of importance to know how the moneyis spent. The use and cost of X-rays in family practice, andwhat factors influence it, is not well known. The aim of thisstudy is to analyse the use and the cost of X-ray requests infamily practice. A prospective practice study from 16 Icelandiccommunity health centres (HC) with computerised contact dataand their target populations, 12 rural and four urban, was carriedout. The X-ray requests, numbers, types and cost were analysed.Patient and practice characteristics were used to assess variationin X-ray practices. A total of 5173 X-ray requests were recorded,which comprised 3.2% of all office visits. The mean number ofX-ray requests was 24.7 and 14.7/1000 contacts in rural andurban HCs respectively, and 123.1/1000 inhabitants in ruralHCs. The X-ray request rate per individual increased with age,but per contact it was highest among young males. Extremityand chest X-rays were the most common requests. For every 1000individuals added to a practice population, the likelihood ofhaving an X-ray requested decreased by 18%. The use of X-rayexaminations in family practices represents approximately 17%of all ambulatory X-ray use in Iceland. The calculated costof X-rays requested in this study was $6157/1000 inhabitantsper year as of October 1993. The rate of X-rays requested differsgreatly among doctors, which indicates potential for savingsin the health care system, through radiology guidelines. Thisstudy indicates that the rate and the cost of X-rays are lowin general practice in Iceland. X-ray facilities should be adequateand accessible to each practice. The results of this study areuseful in quality control, organisation and in the analysisof cost in the health care system. Training of family doctorsneeds to take this information into account.     

Pharmacokinetics of high dose thiotepa in children undergoing autologous bone marrow transplantation.

Pharmacokinetics of high dose thiotepa was studied in 10 children who received this drug as a 2 h infusion at a dose of 300 mg/m2 daily for 3 days. The thiotepa was quantitated using a modification of a previously published gas chromatographic method. Samples were obtained at predetermined times post infusion. The peak plasma concentrations immediately following the infusion ranged from 5.5 to 25.2 (2.0 +/- 6.6) mg/l and the 8 h post infusion ranged from 0.06 to 0.7 (0.32 +/- 0.21) mg/l. The disposition of thiotepa was best described as a simple one compartment open model. The mean (+/- SEM) values for apparent elimination half-life (t1/2 beta), total plasma clearance (CL) and steady volume of distribution (VDss) were 1.3 x h, 11.25 (1.73) l/h/m2 and 19.38 (2.58) l/m2 respectively. In conclusion the pharmacokinetics of high dose thiotepa in children between 2 and 12 years of age do not appear to vary from those reported in children receiving 75 mg/m2 or adults receiving similar doses.     

Hyaluronic acid accumulation; the mechanism behind graft rejection edema

Hyaluronic acid (HA) is an important stabilizing consistuent of the loose connective tissue and regulates water homeostasis. Thus, excessive accumulation of HA in interstitial tissue immobilizes water and may thereby contribute to interstitial tissue edema. By the use of biotin labelled core protein and an avidin-enzyme system, we visualized HA in grafted rat kidney, rat heart, rat small bowel and also in human kidneys. By an extraction procedure the tissue amounts of HA were measured in the experimental grafts. Simple techniques for measuring water content were also employed. The extracellular amounts of HA increased between 100 % and 350 % in rejecting tissues as compared to syngeneic controls. The relative water content also increased and correlated well with the HA accumulation. The clinical value of these experimental observations was confirmed in human transplantation where rejecting kidney allografts demonstrated a highly significant increase in HA staining in the interstitium as compared to non-rejecting biopsy specimens. We therefore concluded that transplantation edema — a key features of graft rejection — is regulated by the accumulation of HA not only under experimental conditions but also in the clinical setting.     

High resolution computed tomography as a predictor of lung histology in systemic sclerosis.

BACKGROUND: The relative proportions of fibrosis and inflammation seen by open lung biopsy examination is a predictor of disease outcome in fibrosing alveolitis. This study was designed to assess the ability of high resolution computed tomography to predict the histological appearance of open lung biopsy specimens from patients with systemic sclerosis. METHODS: Twenty abnormal biopsy specimens from 12 patients were assessed; abnormalities were categorised as fibrotic (fibrosis exceeding inflammation) or inflammatory (inflammation equal to or exceeding fibrosis). Computed tomography appearances were scored for the lobe from which the biopsy specimen was taken; scans were graded from parenchymal opacification alone through to a reticular pattern alone. RESULTS: Two lobar appearances were identified on computed tomograms: amorphous parenchymal opacification equal in extent to reticulation (grade 3) and a predominantly reticular pattern (grade 4). There was a significant association between a fibrotic histological appearance and a grade 4 computed tomogram, and between an inflammatory histological appearance and a grade 3 computed tomogram. Computed tomography grade 4 was associated with a fibrotic histological appearance in 12 out of 13 lobes, and grade 3 with an inflammatory histological appearance in four out of seven lobes. CONCLUSION: Computed tomography discriminated between biopsy specimens that were predominantly fibrotic and a smaller group with a larger amount of inflammation.     

Model system for removing neuroblastoma cells from bone marrow using monoclonal antibodies and magnetic immunobeads

Variables effecting removal of neuroblastoma cells from bone marrow using monoclonal antibodies and magnetic immunobeads were studied. Human neuroblastoma cell lines were labeled with the supravital DNA stain Hoechst 33342, seeded into normal bone marrow, incubated with monoclonal antibodies recognizing neuroblastoma cell surface antigens (HSAN 1.2, antibody 459, antibody 390, BA-1, and Leu-7), and then mixed with magnetic microspheres coated with goat anti-mouse immunoglobulin. Tumor cells that attached to the magnetic immunobeads were then removed from the marrow with magnets. The efficacy of tumor cell removal depended on the amount of monoclonal antibody bound to tumor cells and the immunobead/tumor cell ratio. In addition, two cycles of purging with both monoclonal antibodies and immunobeads was superior to one cycle. Using a cocktail of the five antibodies, 3 to 4 logs of tumor cells could be depleted from marrow with good recovery of viable hematopoietic cells.     

C4d immunohistochemical stain is a sensitive method to confirm immunoreactant deposition in formalin-fixed paraffin-embedded tissue in bullous pemphigoid

Background:  Bullous pemphigoid (BP) is characterized clinically by the onset of pruritic urticarial plaques, vesicles and bullae in a predominantly elderly population. While the diagnosis may be suspected on routine hematoxylin and eosin histology of formalin-fixed paraffin-embedded tissue, fresh-frozen tissue must be used to show the immunologic nature of the bullous process by direct immunofluorescence (DIF). The diagnosis is further confirmed and separated from epidermolysis bullosa acquisita (EBA) by subsequent serologic studies to detect antibodies directed against BP180 and BP230 antigens and characteristic antibody deposition on salt-split skin.
Methods:  Using a polyclonal complement fragment 4d (C4d) antibody, we stained formalin-fixed paraffin-embedded skin biopsy specimens from cases of BP and controls.
Results:  We showed characteristic linear basement membrane deposition of C4d in formalin-fixed paraffin-embedded tissue in seven of nine cases diagnosed as BP vs. EBA by DIF on fresh-frozen tissue. None of the four controls for which we had adequate tissue were positive.
Conclusion:  These results indicate that formalin-fixed paraffin-embedded tissue can be stained for the immunoreactant C4d to show characteristic immunoreactant deposition, potentially obviating the need for repeat biopsy for DIF and allowing clinicians to proceed to serologic confirmation of BP.     

THE PURIFICATION OF OYSTERS AS A CONSERVATION MEASURE

Give the oyster a chance to cleanse itself and typhoid will be as preventable here as with domestic water supplies. This is the motif of this paper by Dr. Wells, who is no new hand at discussing shellfish problems. "It can be considered a conservation measure," he urges.     

Spectrum of ENU-induced mutations in phenotype-driven and gene-driven screens in the mouse

N-ethyl-N-nitrosourea (ENU) mutagenesis in mice has become a standard tool for (i) increasing the pool of mutants in many areas of biology, (ii) identifying novel genes involved in physiological processes and disease, and (iii) in assisting in assigning functions to genes. ENU is assumed to cause random mutations throughout the mouse genome, but this presumption has never been analyzed. This is a crucial point, especially for large-scale mutagenesis, as a bias would reflect a constraint on identifying possible genetic targets. There is a significant body of published data now available from both phenotype-driven and gene-driven ENU mutagenesis screens in the mouse that can be used to reveal the effectiveness and limitations of an ENU mutagenesis approach. Analysis of the published data is presented in this paper. As expected for a randomly acting mutagen, ENU-induced mutations identified in phenotype-driven screens were in genes that had higher coding sequence length and higher exon number than the average for the mouse genome. Unexpectedly, the data showed that ENU-induced mutations were more likely to be found in genes that had a higher G + C content and neighboring base analysis revealed that the identified ENU mutations were more often directly flanked by G or C nucleotides. ENU mutations from phenotype-driven and gene-driven screens were dominantly A:T to T:A transversions or A:T to G:C transitions. Knowledge of the spectrum of mutations that ENU elicits will assist in positional cloning of ENU-induced mutations by allowing prioritization of candidate genes based on some of their inherent features.