Biomedical subjects

H Marchant

Publications and source records attributed to H Marchant.

12 recordsLinked to original sources

PubMed2003

Bilateral vocal fold palsy caused by chronic motor axonal neuropathy.

The authors report a first case of chronic motor axonal neuropathy involving ENT manifestations, in a 64-year-old male presenting with gait difficulties, effort dyspnoea and dysphonia. Eleven months after the first symptoms, he developed severe hypoventilation, limb weakness and bilateral vocal fold palsy and had to be intubated for respiratory failure. The diagnosis of chronic motor axonal neuropathy was suspected on clinical and electrophysiological grounds. The patient improved dramatically after a five-day course of 0.4 g/kg intravenous immunoglobulin. He is still being treated with methylprednisolone 0.5 mg/kg every other day and remains stable. We conclude the bilateral vocal fold palsy may be associated with chronic motor axonal neuropathy and that the immunosuppressive treatment may be effective in such cases.

Axons↗

PubMed2000

Correlation of galectin-3/galectin-3-binding sites with low differentiation status in head and neck squamous cell carcinomas.

The accurate determination of levels of differentiation is of prognostic value in human head and neck squamous cell carcinomas (HNSCCs). Because the deliberate selection of biochemical determinants accompanying certain stages of differentiation can refine the predictive power of histochemical assessments, the application of the quantitative evaluation of staining distribution and intensity by computer-assisted microscopy is one prerequisite to potential improvements. We used 2 innovative approaches with peanut agglutinin based on encouraging results with respect to common lectin-histochemistry. First, we used a custom-made neoglycoprotein to monitor the presence of Thomsen-Friedenreich (T) antigen-binding sites. Second, we measured the presence of 2 galectins immunohistochemically and, at the same time, measured lectin-histochemically the presence of accessible ligands for the endogenous lectins. We also monitored the presence of calcyclin, a protein with relevance to cell cycle progression or exocytosis. With 61 cases of HNSCC as their basis, including 31 oral, 20 laryngeal, and 10 hypopharyngeal lesions, the data show that the main modifications observed in connection with a loss of differentiation are related to a modification in the levels of both galectin-3/galectin-3-binding site and T-antigen/T-antigen-binding site expressions. The data obtained also suggest that galectin-3 could act as an acceptor site for the T antigen. Because the level of differentiation is known to be indicative of the recurrence rate in HNSCCs and our data clearly indicate that galectin-3 and the T antigen (and their respective binding sites) are involved in dedifferentiation processes, further investigation is warranted into the roles of galectins in HNSCC tumor progression and recurrence analysis.

Aged↗

PubMed1999

The levels of expression of galectin-1, galectin-3, and the Thomsen-Friedenreich antigen and their binding sites decrease as clinical aggressiveness increases in head and neck cancers.

BACKGROUND: The aim of this study was to investigate whether an increase in malignancy level is accompanied by significant modifications of the expression of galectin-1, galectin-3, and Thomsen-Friedenreich antigen (T antigen) as well as the expression of binding sites for these three markers in head and neck squamous cell carcinomas (HNSCCs). METHODS: Immunohistochemical and glycohistochemical staining reactions were carried out with antibodies, labeled lectins, and a custom-made neoglycoprotein on the basis of histologic slides from a retrospective series of 40 normal and 75 HNSCC formalin fixed, paraffin embedded tissues, and were quantitatively described with the aid of computer-assisted microscopy. RESULTS: Whatever the histologic type, the epithelial tissues in HNSCC exhibited very significantly (P < 0.01 to P < 0. 0001) lower amounts of galectin-1, galectin-3, and T antigen and their respective binding sites than their corresponding normal counterparts. The tumors of the larynx differed very significantly (P < 0.0001 to P < 0.000001) from all the other tumor types. A loss of differentiation in the HNSCCs is accompanied first by the loss of expression of galectin-3 and galectin-3-reactive sites and then by that of the T antigen and its binding site(s). The opposite feature was observed when the parameters associated with the TNM classification were taken into account. The negative lymph node HNSCCs could be distinguished (P = 0.02) from the positive lymph node HNSCCs on the basis of a loss of galectin-3 expression. The modifications occurring in the extent of expression of galectin-1 and galectin-1-reactive sites were relatively marginal in comparison with those observed for galectin-3-dependent and T- antigen-dependent staining. CONCLUSIONS: The decrease in the extent of expression of galectin-3 and galectin-3-reactive sites, T antigen and T antigen-binding sites, and, to a lesser extent, galectin-1 and galectin-1-reactive sites correlates significantly with an increasing level of clinically detectable HNSCC aggressiveness.

Adjuvants, Immunologic↗

PubMed1999

Math-Fact Retrieval as the Cognitive Mechanism Underlying Gender Differences in Math Test Performance.

Males from select populations receive better scores on standardized math achievement tests than females. The research reported in this article evaluates the hypothesis that the reason for these differences is that males are faster at retrieving basic math facts. Studies 1-3 demonstrate that math-fact retrieval predicts performance on math achievement tests with students in grades 5-8 and in college. Studies 4-6 show that males and females in grades 2-8 and in college have different patterns of math-fact retrieval performance and that males at the high positive end of the retrieval distribution are faster than comparable females. Study 5 also demonstrates that math-fact retrieval varies in three populations (Anglo-American, Chinese-American, Hong Kong Chinese) and that speed of retrieval improves with practice. Studies 7-9 tested the hypothesis that males are faster than females on retrieval tasks in general. Study 7 showed that there were no gender differences on simple retrieval tasks, and Studies 8 and 9 showed that females were slightly faster than males on verbal-processing tasks. The General Discussion indicates that the math-fact retrieval hypothesis is consistent with previous research. It also relates the math-fact retrieval hypothesis to theories of cognitive performance and introduces the practice and engagement hypothesis. This hypothesis explains the origin of gender differences in math and reading and relates those differences to the existing literature on gender differences in academic performance. The article concludes with a description of needed future research and a discussion of the educational implications of the math-fact retrieval hypothesis. Copyright 1999 Academic Press.

Journal Article↗

PubMed1999

Reply to the Commentaries on the Math-Fact Retrieval Hypothesis.

Geary and Wigfield and Brynes (this issue) point out a number of limitations of the math-fact retrieval hypothesis that we agree with. For instance, we acknowledge that whereas the correlational evidence we offer in our article (this issue) provides suggestive evidence for a link between math-fact retrieval and gender differences in math test performance, that evidence is not compelling. We also acknowledge that even if it is the case that math-fact retrieval is one of the cognitive mechanisms responsible for the gender differences in math performance, there are still many aspects of gender differences in math performance that need to be understood. We also point out a number of areas where we disagree. Most prominently, we do not believe that the spatial cognition hypothesis or affective/motivational hypotheses account for two significant literatures-gender differences in test performance and gender differences in grade performance. We discuss the basis for our beliefs and close with a discussion of the need for intervention research that will resolve some of the issues discussed in the series of articles in this issue. At the end of the article we also present a very speculative hypothesis that would knit together all of the positions presented in the articles in this issue of CEP. Copyright 1999 Academic Press.

Journal Article↗

PubMed1998

Quantitative glycohistochemistry defines new prognostic markers for cancers of the oral cavity.

BACKGROUND: Histopathologic grading and clinical staging cannot provide a precise prognosis of oral cavity cancer patients. The use of glycohistochemical markers may improve the level of prognostic accuracy of such conventional classification systems. METHODS: Computer-assisted microscopy was employed in a series of 40 oral cavity cancers to determine quantitatively the percentage of positive cells, the staining intensity, and the level of staining heterogeneity for 3 glycohistochemical markers, including peanut agglutinin (PNA), Thomsen-Friedenreich antigen (T antigen) as part of a neoglycoprotein, and sarcolectin. Data were evaluated by discriminant analysis. RESULTS: Although the level of differentiation (P < 0.01 to P < 0.001) and the T variable of the TNM staging system (P < 0.05 to P < 0.01) related mainly to the level of expression of the acceptor sites for PNA and the T antigen, the patient survival period (P < 0.05) was largely a fraction of the level of expression of the acceptor sites for the carrier-immobilized T antigen and for sarcolectin. CONCLUSIONS: In oral cavity cancer, determining the level of acceptor sites for PNA, T antigen, and sarcolectin provides useful information on histopathologic differentiation, clinical staging, and survival. Because these processes of determination were carried out quantitatively, a discriminant model was set up, which enabled the level of oral cavity cancer aggressiveness to be characterized precisely. The current methodology described in this article should therefore afford pathologists original and quantitative (and thus objective) prognostic markers for oral cavity cancers.

Adult↗

PubMed1998

[Value of laser CO2 myringotomy in the treatment of seromucous otitis].

To date serous otitis media is usually treated by surgical setting of ventilating tubes. This technique provides good results on auditory acuity, however, complications such as chronic otorrhea, tympanosclerosis and tympanic perforation are rather frequently encountered. We present the results of our technique for treatment of serous otitis media consisting in a CO2 laser myringotomy. This technique was applied in 20 consecutive adult ears. The operatory microscope was connected with a co-axial CO2 laser device. The 20 myringotomies performed without insertion of ventilating tubes by this technique were all closed after 4 weeks with an average closing time of 17 days with no complications. In 60% of the cases, the serous otitis media was cured after a period of three months. CO2 laser myringotomy is a valuable alternative technique in the treatment of serous otitis media.

Adult↗

PubMed1991