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A Vermersch

Publications and source records attributed to A Vermersch.

8 recordsLinked to original sources
PubMed2000

Hemispheric asymmetry in cortical control of memory-guided saccades. A transcranial magnetic stimulation study.

To study the temporal organisation of memory-guided saccade control we used single-pulse transcranial magnetic stimulation (TMS) over the left posterior parietal (PPC) and prefrontal cortex (PFC) in eight healthy subjects. TMS was applied either following presentation of a visual target, i.e. 160, 260, and 360 ms after the flashed point, or during the period of memorisation, i.e. between 700 and 1500 ms, or finally 100 ms after extinguishing of the central fixation point (i.e. 2100 ms after the target presentation). Latency of memory-guided saccades and the percentage of error in amplitude (PEA) was measured and compared with results without stimulation.TMS over the left PPC 100 ms after the extinguishing of the central fixation point significantly increased memory-guided saccade latency bilaterally. Furthermore, stimulation over the left PFC had a significant effect on the PEA of contralateral memory-guided saccades when applied during the period of memorisation, i.e. between 700 and 1500 ms.In a previous study using identical methodology [13: Müri RM, Vermersch SI, Rivaud S, Gaymard B, Pierrot-Deseilligny C. Effects of single-pulse transcranial magnetic stimulation over the prefrontal and posterior parietal cortices during memory-guided saccades in humans. Journal of Neurophysiology 1996;76:2102-2106], we found that TMS over the right PPC increased the contralateral PEA when applied 260 ms after the flash, the effects on saccade latency after right PPC stimulation or on the PEA after right PFC stimulation being similar to those observed here. Taken together, these results show that (1) a hemispheric asymmetry in the preparation of memory-guided saccade amplitude during the early phase of sensorimotor integration exists, (2) memory-guided saccade triggering is controlled by PPC on both sides, and (3) PFC on both sides are involved in spatial working memory performance.

Adult↗
PubMed1996

A study of two procedures of HIV-1 isolation from whole blood cultures.

Culture techniques for isolation of HIV-1 from small amounts of whole blood (WB) treated with anticoagulant have been reported and gave results identical to those of culture of separated peripheral blood mononuclear cells. Some authors obtained much higher isolation rates when EDTA was used instead of heparin. We compared two previously described techniques for cultivation of HIV-1 from WB of adult HIV+ patients staged according to the CDC classification. In addition, we assessed the influence of the type of anticoagulant used for the collection of blood in viral replication in cell cultures from whole blood. Small volumes of WB treated with either heparin or EDTA were cocultivated with phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PHA-PBMC) from healthy donors. We used two procedures for WB culture: procedure I, based on the culture of 250 microliters of WB with 1 x 10(6) PHA-PBMC from donors; and procedure II based on the culture of 500 microliters of WB with 4 x 10(6) PHA-PBMC from donors. The cocultures were placed in 24-well plates and incubated for as long as 28 days in medium containing interleukin 2 (IL-2). Twice weekly half of the medium was replaced with fresh medium. In procedure II, one million fresh PHA-PBMC from donors was added on the 7th day of culture. The culture supernatant was assayed for the presence of HIV-1 p24 antigen in an enzyme immunoassay. The kinetics of HIV-1 replication in cultures of WB from 7 AIDS patients were similar using procedures I and II. In 8 HIV+ patients the isolation rate was higher with heparin- than with EDTA-treated samples. The isolation rate was higher in AIDS patients (n = 8) than in others with both methods. In stage IV patients without AIDS (n = 8) we failed to isolate HIV-1 in 1 patient with procedure I, whereas we succeeded with procedure II. In stage II, HIV-I was isolated in 1 of 4 patients with both methods. HIV was isolated in cultures of WB from patients receiving zidovudine or related nucleoside analogues and in cultures of WB from untreated patients. HIV-1 could not be isolated from WB of patients with more than 400 CD4+ T lymphocytes in their peripheral blood (n = 4); however, it was isolated from 14 of 16 patients with less than 400 CD4+ T lymphocytes. Our results suggest that procedure II is more sensitive than procedure I and that heparin is better than EDTA for collecting WB. We showed that the rate of HIV-1 isolation from WB increased in advanced-stage patients. Further studies are needed to define the clinical applications of WB culture.

Acquired Immunodeficiency Syndrome↗
PubMed1994

[Pancreatic-portal fistula. A rare complication of chronic pancreatitis].

We report a 40-year-old patient with complication of chronic pancreatitis as a pancreatico-portal fistula. The patient had subcutaneous nodular fat necrosis of the lower limbs resembling Weber-Christian syndrome, and amylasic ascitis. The diagnosis was established with retrograde endoscopic cholangio-pancreatography which found three pancreatic pseudocysts and a communication with the portal venous system. A portal thrombosis with cavernum was studied with color echo-Doppler and arteriography. The echo-endoscopy was performed for the first time in this complication and its significance estimated. The evolution was quickly and spontaneously favourable. That is a very rare complication of chronic pancreatitis and an expectant conservative management can be adopted.

Adult↗
PubMed1991

Elevated serum levels of soluble interleukin-2 receptor: a marker of disease activity in the hypereosinophilic syndrome.

We report here the presence of very high serum levels of the soluble interleukin-2 receptor (sIL-2R) in patients with blood hypereosinophilia with or without detectable markers of malignancy or signs of visceral involvement. The highest sIL-2R levels were observed in 16 eosinophilic patients with T-cell lymphoma (3,440 to 79,500 U/mL). Elevated levels of sIL-2R were also present (1,330 to 22,500 U/mL) in sera from 38 patients with the hypereosinophilic syndrome (HES) without detectable T-cell lymphoma. In this group of patients, the highest levels were noted in the patients with the malignant form of HES. Significantly lower levels were measured in sera of patients with hypereosinophilia associated with parasitic diseases, allergic disorders, or other miscellaneous diseases. Elevated serum sIL-2R levels were not closely paralleled by changes in the number of CD25-positive peripheral blood mononuclear cells as assessed by flow cytometric analysis. However, expression of IL-2R messenger RNA was detected in blood mononuclear cells collected from HES patients. In eight eosinophilic patients with T-cell lymphoma, the serum sIL-2R levels were significantly correlated with the eosinophil counts, and with the total number of blood hypodense eosinophils. alpha-Interferon (alpha-IFN) therapy resulted in both a dramatic clinical improvement and a rapid decrease in sIL-2R levels and blood hypereosinophilia. Similar beneficial effects of alpha-IFN were noted in patients with malignant HES who lacked a detectable T-cell lymphoma. Our data indicate that HES is associated with elevated serum IL-2R levels. The highest levels were observed in the most severe forms of HES with hematologic markers of malignancy or evident visceral involvement. Serum levels of sIL-2R might represent a useful indicator for the management of HES patients. In addition, the respective changes of sIL-2R and blood eosinophilia might reflect distinct processes of mononuclear cell activation affecting the eosinophil lineage.

Adult↗
PubMed1990

Type 2 diabetes in the elderly: an assessment of metformin (metformin in the elderly).

Metformin efficacy and safety in type 2 diabetes has not been studied in the elderly patient under conditions pertaining to clinical practice. We have therefore, studied prospectively over two months 24 patients aged between 70-88 years with 115% mean ideal body wt and glycemic control greater than 10 mol.l-1 fasting and/or greater than 14 mol.l-1 postprandial, and/or an HbA1 value greater than 10%. At entry into the study, patients were on metformin + sulfonylurea (n = 15), sulfonylurea (n = 3), metformin (n = 2), insulin (n = 1) or diet alone (n = 3). They received metformin as the sole therapy when possible (sulfonylureas were discontinued in 9 cases) at a dosage of either 850 mg or 1,700 mg/day dependent on creatinine clearance values of 30-60 ml.min-1 (n = 11) and greater than 60 ml.min-1 (n = 13), respectively. Compared to pretreatment values, glycemic control at 1 and 2 months were unchanged, with metformin blood levels remaining within expected values for both dosage groups. Blood lactate levels remained unchanged in the high dosage group but were reduced (p less than 0.05) on 850 mg/day probably because of the reduction of metformin dosage in patients already treated prior to the study. It is concluded that provided the dosage is adjusted to renal function, the metabolic tolerance of metformin therapy is satisfactory in the elderly type 2 diabetic patient. With regard to efficacy, longer observations are needed to know whether this therapy may offer on a long-term basis equivalent glycemic control compared to other treatment modalities.

Aged↗