The visual word form area: a prelexical representation of visual words in the fusiform gyrus

Event-related fMRI was used to test the hypothesis that the visual word form area in the left fusiform gyrus holds a modality-specific and prelexical representation of visual words. Subjects were engaged in a repetition-detection task on pairs of words or pronounceable pseudo-words that could be written or spoken. The visual word form area responded only to written stimuli, not to spoken stimuli, independently of their semantic content. We propose that the occasional activation of the fusiform gyrus when listening to spoken words is due to the topdown recruitment of visual orthographic or object representations.     

FDG-PET improves the staging and selection of patients with recurrent colorectal cancer

Whole-body fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) has proved effective in the diagnosis and staging of recurrent colorectal cancer. In this study, we analysed how PET affects the management of patients with recurrent colorectal cancer by permitting more accurate selection of candidates for curative resection. The data of 79 patients with known or suspected recurrent colorectal cancer were analysed. Conventional imaging modalities (CIM) and PET results were compared with regard to their accuracy in determining the extent and the resectability of tumour recurrence. Recurrence was demonstrated in 68 of the 79 patients. The data indicate that PET was superior to CIM for detection of recurrence at all sites except the liver. Based on the CIM+PET staging, surgery with curative intent was proposed in 39 patients and was indeed achieved in 31 of them (80%). PET was more accurate than CIM alone in predicting the resectability or non-resectability of the recurrence (82% vs 68%, P=0.02). It is concluded that whole-body FDG-PET is highly sensitive for both the diagnosis and the staging of patients with recurrent colorectal cancer. Its use in conjunction with conventional imaging procedures results in a more accurate selection of patients for surgical treatment with curative intent.     

Radiographic skeletal survey and radionuclide bone scan in Langerhans cell histiocytosis of bone

Background. The lack of a consensus in the literature on the imaging strategy in Langerhans cell histiocytosis (LCH) bone lesions in childhood.Objective. To evaluate the relative value of radionuclide bone scan (RBS) and radiographic skeletal survey (RSS) in the detection of LCH bone lesions, both in the initial work-up of the disease and during the follow-up period.Materials and methods. Ten children with bone lesions evaluated by means of RSS and RBS in a retrospective study (1984–1993).Results. Fifty radiologically and/or scintigraphically abnormal foci were detected: 27 anomalies in the initial work-up (12 by both RSS and RBS, 8 by RSS only and 7 by RBS only) and 23 additional anomalies during follow-up (10 by both RSS and RBS, 10 by RSS only and 3 by RBS only). RSS+/RBS- lesions (n =18) are more frequently encountered in the skull (P = 0.038), and more frequently lack radiologic signs of osteoblastic activity (P = 0.020), than RSS+/RBS+ lesions (n = 22). RSS-/RBS+ abnormalities (n = 10) were most frequently insignificant.Conclusion. In the initial work-up both RSS and RBS should be carried out, while in the follow-up only RSS should be performed.     

Outcome of cadaver kidney transplantation in small children

Cochat P, Castelo F, Glastre C, Martin X, Stamm D, Long D, Lavocat M-P, Hadj-Aïssa A, Lyonnet D, Floret D. Outcome of cadaver kidney transplantation in small children. Acta Pædiatr 1994;83:78–83. Stockholm. ISSN 0803–5253 Small children have often been reported to have poor outcome after kidney transplantation (KT). Recent reports from North America have shown that the use of living-related donors improves patient and graft survival. We report the experience in one centre of primary cadaveric KT using sequential immunosuppression in nine children aged 8–30 months and weighing 5.4–9.8 kg; donors were 0.7–12.3 years old. Four patients had pre-emptive KT and the other five were on peritoneal dialysis; the mean ± SD waiting time was 2.0 ± 2.4 months. Perioperative care has been published previously. The surgical approach was intraperitoneal if the aorta and vena cava were used (n= 7) and extraperitoneal for common iliac vessels anastomosis (n = 2); the duration of surgery was 3.5 ± 0.9 h and the time for vascular anastomosis was 32 ± 6 min. The recipients received ATG, azathioprine, prednisone and delayed administration of cyclosporin A. The patients were followed for 12–98 (median 41) months and showed good graft function (inulin clearance 63–100 ml/min/1.73 m²); only one child with recurrent haemolytic uraemic syndrome lost his graft three months post-transplantation and died after he had received a second graft. None of the recipients required post-transplant dialysis; arterial hypertension involved four children and was related to graft artery stenosis in two. Growth improved by 0.24 ± 0.48 SD score of height per year. Compared to earlier reports on cadaver transplantation in small children (about 40% graft survival after five years) and to the outcome of chronic peritoneal dialysis, the present results are better and appear to be similar to those obtained with living-related donor transplantation.     

Diagnostic accuracy of the fibrotest in hemodialysis and renal transplant patients with chronic hepatitis C virus

BACKGROUND: An accurate diagnosis of hepatitis C virus (HCV)-related liver lesions is mandatory in dialysis patients and kidney recipients to better define the treatment of and contraindications to kidney transplantation. The aim of this study was to assess the diagnostic accuracy of the fibrotest (a noninvasive method to assess liver fibrosis in HCV on a scale from 0 to 1) in hemodialysis and renal transplant patients infected by chronic HCV. METHODS: In all, 110 patients with biopsy-proven HCV (60 renal transplant recipients and 50 hemodialysis patients), determined using the METAVIR scoring system, were studied. RESULTS: Forty-six percent of patients had fibrosis > or =F2. A positive predictive value of a score >0.6 for the presence of significant fibrosis by comparison with liver biopsy was 71%, and an negative predictive value of < 0.2 for excluding significant fibrosis was 77%, respectively. The areas under the ROC curves for the diagnosis of significant fibrosis were 0.66, 0.47, and 0.71 in the global population, hemodialysis patients, and renal transplant patients, respectively. In all, 75% of patients were correctly classified using the fibrotest. If biopsy was restricted to scores in the intermediate range (< 0.6 and >0.2), the index could reduce the indication for biopsy by 47%. The results did not differ significantly in hemodialysis and renal transplant patients. CONCLUSION: The fibrotest has a diagnostic value in hemodialysis and renal transplant patients which is similar to that reported in the general population (75%) and its use could avoid 32% of liver biopsies if it were interpreted in detail in nephrology patients.     

Efficacy and safety of adefovir dipivoxil in kidney recipients, hemodialysis patients, and patients with renal insufficiency

BACKGROUND: This study analyzes the biochemical, serological, and virological efficacy and the safety of adefovir dipivoxil in patients with renal disturbances. METHODS: Twelve patients with lamivudine-resistant hepatitis B virus (HBV) chronic infection were treated for a median time of 15 (3-19) months. The daily dosage was 10 mg initially and then adjusted according to renal function. RESULTS: Median (range) ALT values remained stable: 55 (13-117) and 37 (17-266) UI/L. After the 12th month, the median decline in serum HBV DNA was from 8.76 (6.3-9.7) to 2.97 (1.15-5.65) log10 Eq/ml (median decline of -5.5 log10). No virologic breakthrough was observed. One of the six HBeAg-positive patients lost HBe Ag but without HBe seroconversion; none had HBs Ag loss. There were no significant clinical and biochemical adverse effects. In the 11 nonhemodialysed patients, the creatinine clearance significantly improved from 70 (30-100) to 88 (38-125) ml/mn (P=0.01) and the mean serum creatinine levels increased only slightly from 114 (91-839) to 130 (81-561) micromol/ml (NS). Serum phosphorus remained stable. The urinary level of protein decreased from 0.16 (0.08-8.63) to 0.12 (0.01-0.74) g/day (NS). CONCLUSIONS: Adefovir dipivoxil is safe for the treatment of chronic hepatitis B in patients with varying degrees of renal dysfunction and lamivudine-resistant HBV and results in biochemical and virological efficacy similar to that reported in the general population.     

Ultrastructure of the thyroid in dwarf mice

The thyroid gland of Snell's dwarf mice consists of small follicles with flattened epithelium, partly differentiated cords and undifferentiated masses. Many adipocytes are found. The ultimobranchial cysts are well developed. Parafollicular cells are normal. In the partly organized cords, microfollicular cells and some small follicles limited by two or three cells are seen. The presence of these structures led us to think that they represent the first stages of normal folliculogenesis, described as the fusion of two adjacent unicellular microfollicles. Their further growth is the result of the coalescing of small adjacent follicles or of cellular multiplication. The presence of undifferentiated masses and partly differentiated cords, in dwarf mice, seems due to a developmental arrest rather than to aberrant development. This disorder of organogenesis is ascribed mainly to a lack of pituitary growth hormone.