Time of flight renal MR angiography: utility in patients with renal insufficiency

We studied the renal arteries prospectively in 16 patients with renal insufficiency using a combination of two-dimensional and three-dimensional time of flight magnetic resonance angiography (MRA). Results were compared with conventional angiography. All renal arteries were identified by MRA. Accuracy for classifying renal arteries into patent, moderately (30-70%) stenotic, severely (> 70%) stenotic, or occluded was 91%. With regard to the presence or absence of severe occlusive disease (> 70% stenosis or occlusion) the sensitivity was 100%, with a specificity of 93%.

Urethritis due to Neisseria meningitidis in a London genitourinary medicine clinic population

A retrospective study was performed in a department of genitourinary medicine to determine the prevalence and clinical features of urethral and cervical infection with Neisseria meningitidis among patients being screened for sexually transmitted diseases. During the 28 month period of the study 11 isolates (from 10 patients) of N. meningitidis were identified from 5571 urethral cultures from homosexual men (0.2%). This compares with an isolation rate of 4.7% for N. gonorrhoeae; 1.2% samples screened for chlamydial antigen were positive. There were no isolates from 8992 urethral cultures from heterosexual men or 15,976 cervical cultures. Eight of the cases identified had features of urethritis at diagnosis; 6 were diagnosed initially as non-specific urethritis (NSU) and 2 as gonorrhoea on the basis of microscopy of a urethral smear. Eight of the 10 patients were treated with amoxycillin and/or a tetracycline, and all but one had a clinical and microbiological cure. In the study population the prevalence of N. meningitidis infection was low and restricted to homosexual men; however, it may be associated with symptoms.

A study of 'inappropriate' attendances to a paediatric Accident and Emergency Department

'Inappropriate' attendance to Accident and Emergency Departments (AEDs) has been shown in many studies to be a sizeable problem. However, only one previous study has investigated inappropriate attendance to these departments amongst children. In this paper we report an investigation of 'inappropriate' usage of a children's AED in Nottingham. Information was collected relating to a representative sample of children who attended this department during September and October 1989 by interviewing the adults accompanying them to the AED and by examining the children's AED medical records. Using defined criteria, the doctors treating each child within the AED assessed whether their attendance was 'appropriate' to the department. Nearly a third (30.1 per cent) of the patients studied were subsequently considered to be inappropriate attenders to this department. This proportion was highest amongst younger children, those from families of lower social class and those living closest to the hospital. 'Inappropriate' attendance was not found to relate to the availability of general practitioners. The reasons stated for choosing to attend the AED suggested that these attendances resulted from perceptions of the adult(s) accompanying the children to the department. In view of this finding, action is required to correct these perceptions, although it is recognized that this may be difficult to achieve.

Transfusion associated graft-versus-host disease after cardiac surgery: response to antithymocyte-globulin and corticosteroid therapy

A 63-year-old patient developed graft-versus-host disease (GVHD) after the transfusion of stored, random donor red cell concentrates with coronary artery surgery. The disease was characterised by skin rash, fever, diarrhoea, hepatic dysfunction, pancytopenia and the acquisition of cells bearing human leukocyte antigens of a blood donor. Clinical and histologic improvements were noted with antithymocyte-globulin and corticosteroid therapy, as seen in some patients with acute GVHD following allogeneic bone marrow transplantation, but the pancytopenia failed to resolve prior to a fatal cerebral haemorrhage. Early aggressive immunosuppressive therapy may be beneficial for transfusion-associated GVHD but strategies for its prevention by limitation of the use of homologous blood need to be addressed.

Blood contamination during venepuncture and laboratory manipulations of specimen tubes

The contamination of the working environment was assessed using a forensic screening test for blood during venepuncture, transport and laboratory manipulation of specimen tubes. Different methods of collecting blood and different commercially available specimen tubes were also assessed using an in vitro system. Blood collected by needle and syringe caused more environmental contamination than did an evacuated container system. Of the commercially available specimen tubes, those with screw tops produced least environmental contamination.

Detection of gastrointestinal bleeding by radionuclide scintigraphy

Scanning with Technetium 99m labeled autologous red blood cells was performed in 59 patients with clinical suspicion of acute and/or intermittent, chronic gastrointestinal bleeding. In 36 patients (61%), a definite site of bleeding could be demonstrated. A strong correlation with other modalities such as upper and lower gastrointestinal endoscopy, contrast angiography, and surgical exploration was found. Overall sensitivity of the procedure was 91%; specificity 100% and accuracy 93.3%. It is suggested that radionuclide scintigraphy provides a completely noninvasive, simple, and sensitive procedure which may be routinely used for the detection and localization of gastrointestinal bleeding.

Comparative in vitro evaluation of the nitinol inferior vena cava filter

An inferior vena cava filter made from nitinol, a thermal shape memory alloy, was evaluated. A series of in vitro experiments was designed to assess its shape recovery, orientation, and positioning after delivery and its embolus-capturing efficiency. For comparison, the Mobin-Uddin and Kimray-Greenfield filters were also tested. The results indicate that the nitinol filter is easily and accurately delivered and is superior to the other filters in its ability to capture emboli. In addition, it showed no tendency to migrate or to elevate the upstream hydrostatic pressures significantly.

Phosphate depletion therapy in two ectopic calcification syndromes

Ectopic calcification may be a complication of a wide variety of pathologic conditions. Subcutaneous calcification frequently results in restriction of motion at joints in addition to cosmetic deformity. Parenchymal tissue calcification may result in decreased organ function. Dietary phosphate restriction and total body phosphate depletion with aluminum containing antacids were used in an attempt to decrease the deposition of subcutaneous calcium phosphate which occurs with two separate syndromes. Two subjects with hyperphosphatemic tumoral calcinosis were studied by metabolic balance, by long-term clinical evaluation, and routine laboratory and radiographic techniques before and after 1 year of phosphate depletion. One patient with a newly described syndrome--normocalcemic, hypercalciuric, subcutaneous calcification--was similarly studied. The etiology of this disorder is unknown. No consistent clinically significant evidence of regression of the lesions was noted in either syndrome, although one patient with tumoral calcinosis did demonstrate some regression of his lesions. It is not clear if this response failure was due to the intrinsic nature of the diseases or to failure of patient compliance secondary to a relatively unpalatable diet.

Insulin binding, internalization, and receptor regulation in cultured human fibroblasts

Insulin binding to receptors was studied using monolayers of cultured normal human fibroblasts. Binding was rapid and inversely related to the incubation temperature; prolonged periods of steady-state binding were achieved at all temperatures studied and the amount of degradation of extracellular insulin was minimal. Competition curves demonstrated half-maximal inhibition of 125I-insulin binding at an unlabeled insulin concentration of 125I-insulin binding at an unlabeled insulin concentration of 7 ng/ml. Scatchard plots of the binding data were curvilinear and revealed that fibroblasts contained about 7,000 receptor sites per cell. Bound 125I-insulin dissociated from fibroblasts with a t 1/2 of 10 min at 30 degrees C and 35 min at 16 degrees C. After 60 min dissociation at 30 degrees C, 45% of the dissociated radioactivity consisted of 125I-insulin degradation products, whereas only 8% of the dissociated material was in the form of degraded products after 60 min of dissociation at 16 degrees C. This indicates that fibroblasts possess a temperature-sensitive receptor-mediated process for insulin degradation. Preincubation of the monolayers with insulin led to a hormone-induced loss of insulin receptors. Thus, incubating cells with 25 ng/ml insulin for 6 h at 37 degrees C caused a 50% reduction in subsequently measured 125I-insulin binding. This hormone-induced receptor loss was sensitive to physiologic insulin levels, with approximately 5 ng/ml causing a half-maximal receptor loss. When monolayers were treated with the lysosomotropic agent chloroquine and subsequently incubated with 5 X 10(-11) M 125I-insulin, a 130% increase in cell-associated radioactivity was observed after 120 min at 30 degrees C. In summary, 1) cultured normal human fibroblasts possess insulin receptors that exhibit kinetic properties and specificity identical to that of other insulin target cells; 2) incubation of fibroblasts with physiologic concentrations of insulin causes a marked loss of cell-surface insulin receptors; and 3) receptor-bound 125I-insulin is internalized through an energy-dependent endocytotic pathway and subsequently degraded by a chloroquine-sensitive reaction.

Regulation of insulin receptors: evidence for involvement of an endocytotic internalization pathway

Cultured human fibroblasts degrade insulin by a receptor-mediated process. When intracellular hormone degradation is inhibited by chloroquine, 125I-labeled insulin internalizes and accumulates intracellularly. In contrast, cultured IM-9 lymphocytes do not degrade receptor-bound insulin or accumulate 125I-labeled insulin in the presence of chloroquine. Insulin-induced receptor loss occurs in both cell types, and chloroquine inhibits this process in fibroblasts but not in IM-9 lymphocytes. Transglutaminase is a membrane-associated enzyme thought to mediate the process of ligand-induced receptor aggregation and internalization; levels of this enzyme were high in fibroblasts but barely detectable in IM-9 lymphocytes. Furthermore, dansylcadaverine--a potent inhibitor of transglutaminase--blocked insulin-induced receptor loss in fibroblasts but was without effect in IM-9 lymphocytes. These results support the concept that insulin receptor regulation is mediated via an endocytotic internalization pathway in human fibroblasts and that the mechanisms of this process differ among cell types.