Nicolas Goasguen

Retention of Plasmodium falciparum ring-infected erythrocytes in the slow, open microcirculation of the human spleen

The current paradigm in Plasmodium falciparum malaria pathogenesis states that young, ring-infected erythrocytes (rings) circulate in peripheral blood and that mature stages are sequestered in the vasculature, avoiding clearance by the spleen. Through ex vivo perfusion of human spleens, we examined the interaction of this unique blood-filtering organ with P falciparum-infected erythrocytes. As predicted, mature stages were retained. However, more than 50% of rings were also retained and accumulated upstream from endothelial sinus wall slits of the open, slow red pulp microcirculation. Ten percent of rings were retained at each spleen passage, a rate matching the proportion of blood flowing through the slow circulatory compartment established in parallel using spleen contrast-enhanced ultrasonography in healthy volunteers. Rings displayed a mildly but significantly reduced elongation index, consistent with a retention process, due to their altered mechanical properties. This raises the new paradigm of a heterogeneous ring population, the less deformable subset being retained in the spleen, thereby reducing the parasite biomass that will sequester in vital organs, influencing the risk of severe complications, such as cerebral malaria or severe anemia. Cryptic ring retention uncovers a new role for the spleen in the control of parasite density, opening novel intervention opportunities.

Colopharyngoplasty for the treatment of severe pharyngoesophageal caustic injuries: an audit of 58 patients.

Objective:The aim of this study was to describe the technique of colopharyngoplasty for the reconstruction of concomitant esophageal and pharyngeal caustic injuries and to evaluate the postoperative course and late functional outcomes. Summary Background Data:Surgical treatment of esophageal and pharyngeal strictures is a difficult challenge because reconstruction at this level interferes with the mechanisms of deglutition and respiration. Several techniques have been described for the treatment of this condition but none is accepted as the gold standard. Methods:Fifty-eight patients (34 men, median age 37 years) underwent colopharyngoplasty for caustic injuries between 1993 and 2005. Forty patients (69%) had a previous psychiatric history of depression (n = 30) or schizophrenia (n = 10). After removal of all scar tissues, the pharyngeal reconstruction was performed with the cervical end of the colic transplant employed for esophageal replacement. Laryngeal resection was associated in half of the patients. Success of the procedure was defined as recovery of nutritional autonomy and airway patency. Results:Operative mortality was 2%. Postoperative complications required reoperation in 16 patients (28%). The functional outcome was evaluated in 46 patients with a follow-up of more than 6 months. The tracheostomy was withdrawn in 42 (91%) patients after a median of 42 days (range, 20–1020). The jejunostomy was removed in 32 patients (70%) after a median of 12 months (range, 2–54). Finally, the procedure was successful in 31 patients (67%). Logistic regression analysis showed that advanced age, a previous history of psychiatric disease, and early reoperation had an adverse impact on fuctional outcome. Seven patients (12%) repeated the suicide attempt. Conclusions:Colopharyngoplasty is a simple and reliable procedure that can be successfully employed to restore the digestive continuity in patients with concomitant esophageal and pharyngeal caustic injuries. Control of the underlying psychiatric disease before reconstruction is a key factor for success.

Evidence of heterogeneity within colorectal liver metastases for allelic losses, mRNA level expression and in vitro response to chemotherapeutic agents.

A goal of oncology is to predict chemosensitivity of tumors. This approach assumes that in a patient all tumor deposits are homogeneous. We have tested the heterogeneity between several samples of the same liver metastasis (LM; intrametastatic heterogeneity) or between multiple LM (intermetastatic heterogeneity) from colorectal cancer in a single patient. In 16 untreated patients, several fragments of LM and nontumorous liver were collected. Heterogeneity to anticancer drug treatment was assessed in vitro on primary tissue cultures on poly‐HEMA‐coated surface with or without the topoisomerase‐I inhibitor metabolite SN‐38. Heterogeneity of response to SN‐38 was observed in 55% of cases from one fragment to another in the same LM and in 64% of cases from one LM to another in the same patient. Allelic losses were characterized on 5q, 8p, 17p, 18q, 22q using 29 microsatellites markers. Seven patients (58%) had a perfect homogeneity for allelic losses in their LM whereas 3 (21%) had intrametastatic and 2 (18%) had intermetastatic heterogeneity. The analysis of gene expression was carried out by real time RT‐PCR quantification using specific probes for TS, TOPO1, ERCC1, and CES2. Level expression of genes tested appeared heterogeneous with average variations of 57(±23)%, 52(±18)%, 53(±18)%, 56(±16)% for TS, TOPO1, ERCC1, and CES2 respectively for intermetastatic variability and 47(±26)%, 36(±14)%, 38(±19)%, and 56(±29)%, respectively for intrametastatic variability. Our results demonstrate intermetastatic and intrametastatic heterogeneity suggesting that pretherapeutic analysis of a single tumor biopsy is likely to lead to a misinterpretation of sensitivity to anticancer treatment.

Lipome colique : cas clinique et revue de la littérature

Colonic lipoma is a rare benign tumor infrequently met in clinical practice. We report a case of symptomatic lipoma of the ascending colon in a 61-year-old woman. Diagnosis was suspected on CT scan. Colotomy with lipectomy was performed. The diagnosis was confirmed by histological examination. Reviewing the literature and combining with our experience, we discuss the clinical features, diagnosis and treatment of this uncommon disease.

Tératome kystique du pancréas.

Resume Le diagnostic preoperatoire de certitude des tumeurs kystiques du pancreas est parfois difficile a etablir. Il repose essentiellement sur les examens morphologiques et le dosage des marqueurs tumoraux intrakystiques, mais ceux-ci peuvent etre pris en defaut s’il s’agit d’une lesion plus exceptionnelle qu’un cystadenome. Nous rapportons l’observation d’une femme de 45 ans operee pour un teratome mature kystique benin avec contingent endocrine dont l’aspect en imagerie et le contenu intrakystique en ACE et CA 72.4 evoquaient un cystadenome mucineux degenere.

Primary Hyperparathyroidism from Parathyroid Microadenoma: Specific Features and Implications for a Surgical Strategy in the Era of Minimally Invasive Parathyroidectomy

BACKGROUND The aim of this study was to identify the specific preoperative characteristics of patients with parathyroid microadenoma and to report their outcomes after surgical treatment. STUDY DESIGN Parathyroid microadenomas (weight < 100 mg) were identified in 62 (6%) of the 1,012 patients operated on for a parathyroid adenoma between 1995 and 2004. Presentation and outcomes after surgery were compared with those of 124 patients operated on consecutively for parathyroid adenoma (>100 mg) during the last year of the study. All patients underwent bilateral surgical exploration of the neck. Success was defined as resection of a pathologic gland combined with normocalcemia at 6 months after operation. Logistic regression was used to test the relationship between groups and potential predictive factors of microadenoma. RESULTS There were 57 women (92%) and the median age was 57 years (range 29 to 77 years). Median preoperative calcemia and parathyroid hormone (PTH) serum levels were 2.64 mmol/L (range 2.31 to 3 mmol/L) and 79 pg/mL (range 30 to 189 pg/mL), respectively. There was no difference in the clinical presentation between patients with microadenoma and adenoma. Preoperative calcium (p < 0.001) and PTH serum levels (p = 0.014) were significantly higher in patients with adenoma. Calcium and PTH serum levels lower than 2.6 mmol/L and 60 pg/mL, respectively, predicted the presence of microadenoma with respective specificities of 0.89 and 0.87. Success rates were similar in the microadenoma and adenoma groups (92% vs 98%; p = 0.11). CONCLUSIONS Mild preoperative elevations of calcium or PTH serum levels should warn about the risk of microadenoma. In this setting, intraoperative difficulties should be expected in identifying the pathologic gland, and bilateral neck exploration should be the preferred surgical approach.