Biomedical subjects

Pierre Kehrli

Publications and source records attributed to Pierre Kehrli.

9 recordsLinked to original sources

PubMed2008

Do medulloblastoma tumors meet the Food and Drug Administration criteria for anti-erbB2 therapy with trastuzumab?

Several publications have recently focused on the erbB2 receptor in pediatric medulloblastomas (MBs) and its prognostic consequence. We determined erbB2 expression in 23 MBs at diagnosis. After DNA extraction, quantitative PCR targeting the erbB2 gene was performed and correlated with FISH analysis and immunohistochemistry. The samples were representative of the spectrum of the disease apart from the absence of large cell MBs. Using the tools validated for breast cancers by the FDA, we did not observe any expression or amplification of erbB2 and hence we speculate that MBs are not a good target for treatment with anti-erbB2 antibodies.

Animals↗

PubMed2006

Altered expression of alpha3-containing GABAA receptors in the neocortex of patients with focal epilepsy.

Impaired transmission in GABAergic circuits is thought to contribute to the pathogenesis of epilepsy. Although it is well established that major reorganization of GABA(A) receptor subtypes occurs in the hippocampus of patients with medically refractory temporal lobe epilepsy (TLE), it is unclear whether this disorder is also associated with alterations in GABA(A) receptor subtypes in the neocortex. Here we have investigated immunohistochemically the subunit composition and neocortical distribution of three major GABA(A) receptor subtypes using antibodies specifically recognizing the subunits alpha1, alpha2, alpha3, beta2/3 and gamma2. Cortical tissue was obtained at surgery from patients with TLE and hippocampal sclerosis (HS; n = 9), TLE associated with neocortical lesions (non-HS; n = 12) and frontal lobe epilepsy (FLE; n = 5), with post-mortem samples serving as controls (n = 4). A distinct laminar and neuronal expression pattern of the alpha-subunit variants was found across the neocortical regions examined in the temporal and frontal lobes in both control and patient tissue samples. In the five patients with FLE, GABA(A) receptor subunit staining was unchanged as compared to controls. In patients with TLE we observed a marked decrease in alpha3-subunit staining in the superficial neocortical layers (I-III), but no change in the deep layers (V and VI) or in the expression pattern of the alpha1 and alpha2-subunits. Reduced expression in alpha3-containing GABA(A) receptors was detected in six out of nine patients of the HS group and four out of twelve patients of the non-HS group. Histopathological changes were present in eight out of the ten patients with decreased alpha3-subunit staining. The selective reduction in alpha3-containing GABA(A) receptors was confirmed using semiquantitative measurements of optical density (OD). The specific changes unique to alpha3-subunit expression in the superficial neocortical layers of patients with TLE suggest that this subtype is of particular significance in the reorganization of cortical GABAergic systems in focal epilepsy.

Adolescent↗

PubMed2006

Neural responses associated with positive and negative emotion processing in patients with left versus right temporal lobe epilepsy.

Studies on emotion processing in patients with temporal lobe epilepsy have dealt mainly with the processing of negative emotions. To further understand the neural basis of emotional disorders in temporal lobe epilepsy, we studied patterns of brain activation induced by implicit processing of negative and positive emotions perceived through facial expressions and emotionally salient stimuli in candidates for surgical treatment of intractable epilepsy. Using functional MRI, we compared, in patients with mesial temporal lobe epilepsy and healthy subjects, the patterns of brain activation elicited by the implicit processing of fearful, sad, and happy faces and pleasant and unpleasant scenes. The results revealed different patterns of activation in patients with left and right mesial temporal lobe epilepsy, compared with healthy subjects, suggesting that the left and right mesial temporal regions are involved differently in emotion processing, which could be related to different contributions in emotional arousal.

Adult↗

PubMed2006

Remote memory in temporal lobe epilepsy.

PURPOSE: The present study aims at characterizing remote memory in patients with temporal lobe epilepsy (TLE); it also considers the impact of its most important variables (lateralization of the lesion, duration of epilepsy, age at onset, and seizure frequency) on remote memory. METHODS: We examined the performance of 38 patients with unilateral TLE (19 right TLE and 19 left TLE) and 35 healthy subjects on six remote memory tasks. Memory for personal events was assessed by using the Autobiographical Memory Interview and the Modified Crovitz Test. Memory for public events was evaluated by means of photographs of famous faces and famous scenes, questions about famous events, and the Dead/Alive Test. RESULTS: Both right-TLE and left-TLE groups had impaired memory for autobiographic episodes and public events relative to normal subjects. In contrast, personal semantic memory was preserved. In addition, an effect of laterality was recorded, with right-TLE patients obtaining significantly better scores than left-TLE patients on every test. Duration of epilepsy, age at onset, and seizure frequency did not influence performance on remote memory measures. CONCLUSIONS: The comprehensive neuropsychological study of 38 TLE patients showed that this neurologic condition affects remote memory systems differently. We discuss the different factors that could account for this pattern of performance on the bases of both functional brain organization and memory theories.

Adult↗

PubMed2006

Towards a definition of the "practical" epileptogenic zone: a case of epilepsy with dual pathology.

Presurgical evaluation for patients with drug-resistant epilepsy requires the definition of various zones that have a variable spatial relationship with the epileptogenic zone. All the available methods to directly measure the actual seizure-onset zone and to define "the minimum amount of cortical tissue that must be resected to produce seizure-freedom" have significant limitations. We report on the case of a patient with dual pathology (hippocampal sclerosis and a post-traumatic scar) and discuss the contribution of the various presurgical investigations that led to surgery and seizure-freedom.

Adult↗

PubMed2005

Selective memory impairment for public events in a patient with left temporal lobe epilepsy.

Highly selective memory impairment for public events was demonstrated in a patient (JR), who suffered from temporal lobe epilepsy (TLE). We successfully trained JR's memory for a set of news events and discuss, on those bases, the characteristics of news events processing that may have contributed to its increased vulnerability relative to autobiographical memory (AbM).

Epilepsy, Temporal Lobe↗

PubMed2004

[Brain metastases: a neurosurgical point of view].

The question of accessibility to the recent development of diagnostic and therapeutic tools for brain metastasis patients remains a problem. Advances in neurosurgery, new fields in chemotherapy, radiosurgery and different types of radiation therapy are accompanied by the need of dedicated staff time and materials. The limits of what we can offer to our patients regarding access to treatment and costs have to be clarified through a national consensus. Multimodal strategies must take in account the individual patient as well as accessibility to the different treatment tools. The most important problem remain the ongoing need for radiosurgery and various subtype of new radiotherapy methods.

Brain Neoplasms↗

PubMed2002

Supraorbital eyebrow approach to skull base lesions.

We report our experience with a supraorbital eyebrow minicraniotomy. This technique is suitable to lesions situated in the region of the anterior fossa, suprasellar cisterns, parasellar region and Sylvian fissure. A 50 mm incision in the eyebrow and a supraorbital minicraniotomy is performed. Sixteem patients harboring different lesions were operated on with good postoperative and cosmetic results. We conclude that this approach is safe and useful in selected cases.

Adolescent↗

PubMed2002

[A rare cause of constipation: neurinoma of the fourth lumbar nerve. Case report and review of the literature ].

Constipation is a symptom not to be neglected, especially if the complaint is recent. We report a case where this symptom was the only clinical manifestation of a voluminous retroperitoneal tumor. The tumor was found to be a neurilemmoma of the fourth right lumbar roots, confirmed at pathological examination. Manifestations of extradural neurinomas generally result from compression of neighboring structures. The best preoperative diagnosis approach is magnetic resonance imaging but histology is required for confirmation. The close relations the tumor mass maintains with the unaffected nerve fibers makes resection difficult without postoperative functional consequences. Surgeons discuss the relevance of partial excision in order to preserve the nerve root in case of a benign slow-growing tumor. There does however appear to be a significant recovery of muscle strength even in case of total resection.

Aged↗