Effect of cloxacillin prophylaxis on the bacterial flora of craniotomy wounds

During a double-blind placebo-controlled study, the effect of cloxacillin prophylaxis in craniotomies on samples taken for culture from 334 operation wounds in 279 patients was assessed. Patients and operations were equally divided over the cloxacillin and placebo groups. In the cloxacillin group significantly fewer samples contained microorganisms than was the case in the placebo group both just after the incision was made (p less than 0.05) and just before closure of the wound (p less than 0.001). The contaminating bacteria found most frequently were Propionibacterium acnes and Staphylococcus epidermidis. For material collected immediately after the incision, the percentage of cultures positive for S. epidermidis was significantly (p = 0.001) lower in the cloxacillin group than in the placebo group; the percentage of cultures with P. acnes did not differ between the two groups. For samples taken just before the wound was closed, the percentage of cultures with P. acnes or S. epidermidis was significantly (p = 0.008 and 0.003, respectively) lower in the cloxacillin than in the placebo group. In the placebo group neurosurgical infections occurred with P. acnes and/or S. epidermidis as causative microorganisms; in almost all cases those bacteria could be cultured from the edge of the wound. In none of the patients with an infection caused by S. aureus was the bacteria found in the operation area. In 2/6 infections in the cloxacillin group the infecting microorganisms could be cultured from the operation area. These findings support a significant reduction in the infection rate after craniotomy under cloxacillin prophylaxis compared with placebo.     

Thyrotropin (TSH) receptor modulation by specific TSH receptor antibodies in Graves' disease

In Graves' disease (GD), an antireceptor autoantibody disease, individual variability in the pathogenic interaction between TSH receptors and autoantibodies has been reported. This variability can be due to allotypic (person to person) variability in the receptors or differences in autoantibody amount or specificity. This fundamental issue was investigated by evaluating immunoglobulin G (Ig)-induced TSH receptor modulation in thyroid tissue from 19 patients with GD. TSH receptor modulation by Graves' Ig was defined as the appearance of 1 class of high affinity binding sites, instead of the usual 2 classes of binding sites. Ig-induced modulation of receptors occurred in 9 of 19 (47%) experiments with autologous (patient's own) tissues and correlated with the presence of TSH receptor antibodies, measured as TSH binding inhibitor Igs. Of these 9 receptor-modulating Graves' Ig preparations, 7 (78%) also had a receptor-modulating effect in other patient's (homologous) thyroid tissue. Nine of the 10 Graves' Ig preparations that were negative for TSH receptor-modulating activity in autologous thyroid tissue were tested with other patients' thyroid tissues; 7 (78%) were negative, and all were TSH binding inhibitor Ig negative. We conclude that variability in the occurrence of TSH receptor modulation was associated with the presence or absence of TSH-binding inhibitor Ig. No evidence for allotypic differences in TSH receptors in GD was found.     

Usefulness of FDG-PET to diagnose intravascular lymphoma with encephalopathy and renal involvement

Intravascular lymphoma (IVL) is a rare subtype of extranodal diffuse large B-cell lymphoma. It is characterized by proliferation of neoplastic Lymphoid cells almost exclusively within the lumina of small blood vessels. It can affect virtually every organ system. Due to its rarity and its diverse and heterogeneous clinical presentation, diagnosis is difficult and often made post-mortem. When diagnosed early, it is, however, potentially treatable. We present a young woman with longstanding constitutional symptoms, positive antinuclear antibody, elevated LDH levels and rapidly progressive encephalopathy. FDG-PET scan showed intense uptake in the renal cortex, which prompted us to perform a kidney biopsy which was compatible with IVL. The value of PET in establishing the diagnosis of this rare disease will be discussed.     

Native associations of early hematopoietic stem cells and stromal cells isolated in bone marrow cell aggregates

In suspensions of murine bone marrow, many stromal cells are tightly entwined with hematopoietic cells. These cellular aggregations appear to exist normally within the marrow. Previous studies showed that lymphocytes and stem cells adhered to stromal cells via vascular cell adhesion molecule 1 (VCAM1). Injection of anti-VCAM1 antibody into mice disrupts the aggregates, showing the importance of VCAM1 in the adhesion between stromal cells and hematopoietic cells in vivo. Early hematopoietic stem cells were shown to be enriched in aggregates by using a limiting-dilution culture assay. Myeloid progenitors responsive to WEHI-3CM in combination with stem cell factor (c-kit ligand) and B220- B-cell progenitors responsive to insulin-like growth factor-1 in combination with interleukin-7 are not enriched. We propose a scheme of stromal cell-hematopoietic cell interactions based on the cell types selectively retained within the aggregates. The existence of these aggregates as native elements of bone marrow organization presents a novel means to study in vivo stem cell-stromal cell interaction.     

Magnetic resonance imaging of renal transplants: its value in the differentiation of acute rejection and cyclosporin A nephrotoxicity

The purpose of this study was to determine the value of magnetic resonance imaging (MRI) in the differentiation of acute rejection and cyclosporin A nephrotoxicity in renal transplant kidneys. Fifty-six magnetic resonance examinations in 46 patients were prospectively and independently evaluated by two radiologists. MRI was performed with a 0.5 T superconducting scanner (Gyroscan S5, Philips) applying both T1 and T2 weighted pulse sequences. Biopsies were performed in 22 cases and histology was reviewed. Fifteen normally functioning transplant kidneys and 41 kidneys with graft dysfunction due to cyclosporin A nephrotoxicity, acute rejection, chronic rejection or acute tubular necrosis were studied. Absence or reduction in cortico-medullary demarcation proved to be a sensitive, but non-specific indicator of parenchymal disease. In cases of cyclosporin A nephrotoxicity the allograft was diagnosed as being normal in 90%. The magnetic resonance appearance of acute rejection may be very similar to that of the combination of acute rejection and cyclosporin A nephrotoxicity, chronic rejection or acute tubular necrosis. However differentiation between acute rejection and cyclosporin A nephrotoxicity was possible according to the following statistical data: sensitivity 100%, specificity 75%, positive predictive value 86%, negative predictive value 100%, accuracy 90%.     

The effect of radiotherapy on dysphagia and survival in patients with esophageal cancer

A group of 127 patients with esophageal cancer treated with radiotherapy at different dose levels was retrospectively analysed. It was found that 70.5% of the patients showed improvement of dysphagia and that 54% remained palliated with respect to food passage until their death. The two major prognostic variables with respect to the palliative effect on dysphagia as well as survival were the passage score and the radiation dose. Patients with severe dysphagia (PASS 0 or 1) had a median actuarial DFI and SURV of 3.7 and 6.4 months, respectively, in contrast to 16.0 and 8.7 months for patients who were able to use (semi)solid food (PASS 2 and 3). The median actuarial DFI and SURV of patients treated with a relatively low dose (less than 50 Gy in 5 weeks) were 2.5 and 4.8 months, respectively, compared to 10.1 and 8.3 months, respectively, for patients treated with a relatively high dose.     

Vascularization of head and neck paragangliomas: comparison of three MR angiographic techniques with digital subtraction angiography

BACKGROUND AND PURPOSE: MR angiography of the head and neck region has been studied widely, but few studies have been performed concerning the efficacy of MR angiography for the identification of the specific vascular supply of the highly vascular head and neck paragangliomas. In this study, we compared three MR angiography techniques with respect to visualization of branch arteries in the neck and identification of tumor feeders in patients with paragangliomas. METHODS: Fourteen patients with 29 paragangliomas were examined at 1.5 T using 3D phase-contrast (PC), 2D time-of-flight (2D TOF), and multi-slab 3D TOF MR angiography. In the first part of the study, two radiologists independently evaluated the visibility of first-, second-, and third-order branch arteries in the neck. In the second part of the study, the number of feeding arteries for every paraganglioma was determined and compared with digital subtraction angiography (DSA), the standard of reference in this study. RESULTS: Three-dimensional TOF angiography was superior to the other MR angiography techniques studied (P < .05) for depicting branch arteries of the external carotid artery in the neck, but only first- and second-order vessels were reliably shown. DSA showed a total of 78 feeding arteries in the group of patients with 29 paragangliomas, which was superior to what was revealed by all MR angiography techniques studied. More tumor feeders were identified with 3D TOF and 2D TOF angiography than with 3D PC MR angiography (P < .05), with a sensitivity/specificity of 61%/98%, 54%/95%, and 31%/95%, respectively. Sensitivity was lowest for carotid body tumors. CONCLUSION: Compared with intra-arterial DSA, the 3D TOF MR angiography technique was superior to 3D PC and 2D TOF MR angiography for identifying the first- and second-order vessels in the neck. With 3D TOF angiography, more tumor feeders were identified than with the other MR angiography techniques studied. The sensitivity of MR angiography, however, is not high enough to reveal important vascularization. The sensitivity of MR angiography is too low to replace DSA, especially in the presence of carotid body tumors.