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Biomedical subjects

J Hemet

Publications and source records attributed to J Hemet.

At least 37 records · Page 2Linked to original sources
PubMed1994

Comparative effect of alpha-MSH and b-FGF on neurite extension of fetal rat spinal cord neurons in culture.

Basic fibroblast growth factor (b-FGF) and alpha melanocyte stimulating hormone (alpha-MSH) were tested for their ability to promote axonal elongation on E14 fetal rat spinal cord cell culture, and to support cell survival. A similar development of neurite was observed in alpha-MSH treated cultures or in control cultures, with an axonal length ranging from 87.50 microns to 195.60 microns on day 3. Complete cell death occurred after 6 days of incubation. Whatever the concentration of b-FGF used (0.312-2.5 ng/ml), a significant increase (1.2- to 1.4-fold) in neurite length was observed, with neuronal survival up to 9 days.

Animals↗
PubMed1994

Effect of basic fibroblast growth factor and alpha-melanocytic stimulating hormone on nerve regeneration through a collagen channel.

An experimental study on the rat sciatic nerve was performed to evaluate nerve regeneration through a collagen guide and to study the effects of alpha-melanocytic stimulating hormone (alpha-MSH) and basic fibroblast growth factor (b-FGF) in accelerating axonal elongation. After transection, nerves were repaired over a 7 mm gap using a placental collagen type IV guide. The channel was filled with either a b-FGF solution or an alpha-MSH solution or was produced with b-FGF incorporated into the guide. Four weeks later, only groups in which b-FGF had been injected or incorporated displayed a significant somatosensory evoked potential response. Histological and quantitative analysis of nerve fibres confirmed the existence of nerve continuity in groups receiving an alpha-MSH solution or a channel containing b-FGF. These results demonstrate that alpha-MSH in solution and b-FGF incorporated into a collagen type IV channel enhance peripheral nerve regeneration. However, at 4 weeks, only b-FGF (3 ng) restores functional activity.

Animals↗
PubMed1994

Establishment of adult rat Schwann cell cultures: effect of b-FGF, alpha-MSH, NGF, PDGF, and TGF-beta on cell cycle.

Mitotically active Schwann cells isolated from adult rat sciatic nerve segments were cultivated, using a bivariate BrdU/DNA flow cytometry analysis, to test the effect of b-FGF (10 ng/ml), alpha-MSH (10 ng/ml), NGF (10 ng/ml), PDGF-AB (10 ng/ml), and TGF-beta 1 (10 ng/ml) on the cell cycle. Compared to control or cholera toxin-treated cultures, no significant differences (P < 0.05; Newmann-Keuls test) were observed in the proportion of G0G1 cells, S cells, G2M cells, and in the LI when alpha-MSH, NGF, PDGF-AB, or TGF-beta 1 were present. The S phase duration varied from 6.16 +/- 0.24 to 7.86 +/- 2.6 h, and the deduced potential doubling time was estimated at between 46.70 +/- 7.09 and 56.05 +/- 7.55 h. In contrast, when b-FGF was added to the culture, the cell cycle was significantly modified, and the proportion of G0G1 cells decreased from 68-77% to 59-64%, while the proportion of S cells increased from 14-16% to 24.0-26.4%. Although S phase duration was not significantly changed (6.02 +/- 0.36 h), the 1.7- to 2.8-fold LI increase reduced the potential doubling time to 25.99 +/- 6.13 h. We conclude from these results that only b-FGF-induced adult rat Schwann cells dramatically reenter in cell cycle and that this growth factor may be an axonally derived signal-promoting mitogenesis after nerve injury.

Age Factors↗
PubMed1994

Morphometric analysis of melanocytic tumors. A study of nuclear area and density.

Because the differential diagnosis of melanocytic tumors is sometimes difficult, we performed a morphometric analysis of 20 benign nevi, 20 malignant melanomas, and 10 Spitz's nevi. The nuclear pleomorphism and the maturation to the depth of the tumor were quantified by measuring nuclear area and nuclear density at serial levels of the tumor (every 220 microns of thickness). Data obtained were analyzed statistically. Linear regression was used to represent the variation of nuclear area to the depth, and the standard deviation of nuclear areas reflected nuclear pleomorphism. We attempted to separate different tumors from each other using the Jacknife procedure and morphometric data. Using the Jacknife procedure rather than the usual histological procedures, we were able to distinguish benign nevi from Spitz's nevi and malignant melanoma in as many as 92% of cases, but we distinguished Spitz's nevi from malignant melanoma in only up to 60% of cases. In conclusion, we found it difficult to distinguish between Spitz nevi and melanoma using nuclear morphometric parameters. Other studies using new morphometric parameters are needed in order to improve our ability to make this discrimination.

Adolescent↗
PubMed1994

[Study with flow cytometry of the peritumoral mucosa adjacent to colorectal cancers].

Tumour and peritumoral mucosa were analyzed using flow cytometry in 21 consecutive patients operated on for colorectal carcinoma. Thirteen tumours were DNA aneuploid. No foci of aneuploidy bordering the tumours were detected, regardless of the tumour type. On the other hand, a significant decrease in the proliferative index was observed adjacent to the DNA aneuploid tumours. This study provides an additional argument for segmentary excision in colorectal cancers. Complementary studies are still required to specify the mechanisms of proliferation inhibition in the area of the DNA aneuploid tumours.

Aged↗
PubMed1994

[Pseudomembranous colitis revealing adult hemolytic-uremic syndrome].

A 33 year old woman presented with abdominal pain and bloody diarrhea. A subtotal colectomy was performed. Following surgery the haemolytic uraemic syndrome unmasked. Such surgical forms of haemolytic uraemic syndrome are rare. They demonstrate that the diagnosis is difficult at the initial abdominal period before renal insufficiency and anemia develop. Review of the literature confirms the severe nature of haemolytic uraemic syndrome associated lesions. Haemolytic uraemic syndrome and pseudomembranous colitis with capillary thrombosis would be two forms of a unique affection, i.e. thrombotic microangiopathy.

Adult↗
PubMed1994

[Renal botryomycosis. Clinicopathologic study of a case].

Botryomycosis is a chronic bacterial infection characterized histologically by granules containing bacteria in microabscesses. Although Staphylococcus aureus is the most common causative agent, other bacteria have been reported to cause botryomycosis. Several factors have been hypothesized to be important in the pathogenesis of botryomycosis including foreign bodies, quantity and virulence of bacterial microorganisms and host immunity. We report a case of renal botryomycosis in a 60 year-old woman. The diagnosis was based on clinical findings of Escherichia coli urinary infection, histological findings of granules and immunohistologic findings of anti-Escherichia coli granules staining. This is the seventh reported case of renal botryomycosis.

Escherichia coli Infections↗
PubMed1994

[Thrombotic microangiopathy disclosing human immunodeficiency virus infection. Histological and ultrastructural study].

Thrombotic microangiopathy has recently been documented in association with human immunodeficiency virus infection. The authors present the clinical laboratory, histologic and electron microscopic kidney study features of one case of thrombotic microangiopathy revealing human immunodeficiency virus infection. They also review 28 previously reported cases of thrombotic microangiopathy associated with human immunodeficiency virus infection and discuss different pathogenic hypothesis which could be involved in genesis of human immunodeficiency virus-associated thrombotic microangiopathy.

Adult↗
PubMed1994

[Jaffe-Campanacci syndrome. Report of a case].

Jaffe-Campanacci syndrome is a rare entity characterized by disseminated non ossifying fibromas in association with extraskeletal congenital anomalies: cutaneous, genital, ocular and cardiovascular. Mental retardation is also frequently observed. Pathological fractures are the usual mode of revelation. We report one case original because of causal discovery during orthodontic check-up and because of extraskeletal anomalies not previously described. In fact the true incidence of this syndrome is probably underestimated because of unrecognized features.

Abnormalities, Multiple↗
PubMed1993

Detection of ploidy in colorectal tumors. A comparison between flow cytometry and cytogenetics.

Parallel investigations of ploidy by flow cytometry and cytogenetics were performed in 20 colorectal tumors. Flow cytometry detected an aneuploidy in 13 tumors with DNA indices ranging from 1.13 to 2.21. The other samples exhibited an apparent diploid DNA content. Cytogenetic analyses revealed an abnormal chromosome count in 14 cases and a frequent implication of numerical or structural changes in chromosomes 1, 7, 12, 17, 18, and 20. DNA content evaluated by both techniques was generally concordant with minor discrepancies not exceeding 10%. In six cases, cytogenetics failed to find the cell populations detected by flow cytometry. These results indicate that flow cytometry and cytogenetics are reliable and complementary techniques, particularly in near-diploid tumors, where flow cytometry has some difficulties in detecting variations from diploidy below to 8%.

Adenocarcinoma↗
PubMed1993

Ileal involvement in toxic epidermal necrolysis (Lyell syndrome).

Intestinal involvement in toxic epidermal necrolysis (TEN) has been identified only rarely. This report describes a case of TEN with ileal manifestations characterized by a profuse diarrhea with malabsorption, protein-losing enteropathy, and radiologically by multiple stenosis. After healing of the cutaneous lesions, total parenteral nutrition was initiated, resulting in a decreased diarrhea. However, after one month of total parenteral nutrition, malabsorption and protein-losing enteropathy continued and the radiological lesions were still present with an aspect consistent with a sclerotic process. A surgical resection of the pathological ileal segment was performed with end-to-end anastomosis. Pathological examination of the resected segment showed a necrosis of the ileal mucosa with a pattern similar to that of the epidermal necrosis. No sclerosis was observed. It seems that a prolonged total parenteral nutrition could have induced a complete healing of intestinal lesions. This case report is the first clinical, radiological, and histological study of an ileal involvement in TEN.

Diarrhea↗
PubMed1993

New electron microscopic findings in a case of multicentric reticulohistiocytosis. Long spacing collagen inclusions.

The case of a 68-year-old woman with polyarthropathy and skin nodules is presented. Histologic findings of histiocytes with ground-glass cytoplasm favored the diagnosis of multicentric reticulohistiocytosis. In this article we report new electron microscopic findings of intra- and extracytoplasmic long spacing collagen (type VI). Type VI collagen inclusions are usually found in lymphohistiocytic neoplasms. We believe our findings support the concept of a proliferative rather than inflammatory etiology for multicentric reticulohistiocytosis. It may also give support for the argument of production of collagen by the histiocytic cells of multicentric reticulohistiocytosis.

Aged↗
PubMed1993

Experimental evaluation of bilayered human collagen as a dural substitute.

Many substances have been tried as possible dural substitutes, and different tissues and materials have been evaluated for use in dural repair; however, an entirely satisfactory solution still remains to be found. The authors report an experimental study involving the closure of dural defects in dogs with a new biomaterial, resorbable bilayered human placental collagen, using two types of collagen material. These include a collagen bilayered dural substitute made of oxidized type III + I collagen layer covered by a type IV oxidized collagen film (collagen dural substitute I) and a collagen bilayered dural substitute made of oxidized type III + I collagen layer covered by a type III + I collagen film (collagen dural substitute II). Macroscopic and histological examination, performed over a period of between 15 and 180 days after implantation, showed the resorption of collagen graft and formation of a neomembrane that looked like a neodura within 3 months. No infection and no cerebrospinal fluid fistulae were noticed. Nevertheless, one slight cerebromembranous adhesion was found with collagen dural substitute II. The authors suggest that human resorbable collagen biomaterial could be used as a very satisfactory dural substitute.

Animals↗
PubMed1993

[Comparative study of HMB-45 monoclonal antibody uptake on various benign and malignant melanocytic lesions].

In order to evaluate a possible discriminatory diagnosis interest of HMB-45 monoclonal antibody in different melanocytic population, it was tested on 48 benign and malignant melanocytic lesions embedded in paraffin. There were made of 16 benign nevus (33%), 18 dysplastic nevus (38%) and 14 malignant melanomas (29%). The reaction was positive in 11 benign tumors (69%), 18 dysplastic nevus (100%), and 12 malignant melanomas (86%); negative in 5 dermal nevus (31%) and 2 desmoplastic melanomas (14%). We have researched, by the KHI square (chi 2) statistical test, a relation between the reaction intensity, its cutaneous location, and the tumor type. The reaction intensity is not statistically linked with the tumor type. The cutaneous location of the reaction is statistically more heterogeneous in malignant melanoma than in benign or dysplastic melanocytic lesions. Among the dysplastic nevus, 6 cases (38%), of the familial type, have an heterogeneous reaction looking like the malignant melanoma's one. However, there is no significant difference, in the reaction pattern, between dysplastic and benign lesions. Nevertheless some dysplastic nevus seems to have a phenotypic expression for HMB-45 midway between benign and malignant melanocytic lesion, that will be interesting to precise. Otherwise, the simple use and the staining of HMB-45 monoclonal antibody are of great interest to assess the depth of primary cutaneous melanoma and to diagnose secondary melanoma. However, the negativity of the spindle cell type justify the association of other markers, particularly the S100 protein, which is more sensitive, in the diagnosis of desmoplastic malignant melanoma.

Adolescent↗
PubMed1993

[Glandular tumors of the external auditory canal].

Glandular tumors of the external auditory canal are rare; their etiopathogenesis is uncertain. The term ceruminoma, often used for these tumors, is imprecise. The 1978 who classification is reviewed. The authors describe their experience with 5 cases which illustrate the salient diagnostic therapeutic, and prognostic characteristics of these tumors.

Adenocarcinoma↗