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Biomedical subjects

S Kon

Publications and source records attributed to S Kon.

At least 73 records · Page 4Linked to original sources
PubMed1993

Detection of Epstein-Barr virus DNA and EBV-determined nuclear antigen in angioimmunoblastic lymphadenopathy with dysproteinemia type T cell lymphoma.

Six cases of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD)-like T cell lymphoma were analyzed by immunohistochemical staining, polymerase chain reaction (PCR) and Southern blot analysis. Five cases out of six showed gene rearrangements of the T cell receptor beta chain, indicating the existence of a clonal T cell proliferation. Epstein-Barr virus (EBV) DNA was detected in all six AILD type cases by PCR amplifying the sequence located in the internal repeat I, and confirmed by Southern blot hybridization, using a BamHI-W fragment as a probe. Detection of the EBV genome occurred more frequently as compared with other types of lymphoid disorders. Furthermore, EBV determined nuclear antigen (EBNA) was detected in UCHL-1 (CD45RO, pan-T cell marker) positive cells by immunostaining. These results suggest that a significant number of AILD type cases are T cell origin lymphomas and EBV infection may be relevant to the biological features of this type of lymphoma.

Adolescent↗
PubMed1993

Multiple agminated juvenile melanoma arising on a hyperpigmented macule.

A case of multiple agminated juvenile melanoma (MAJM) arising on a hyperpigmented macule is reported. The patient, a 1-year-old boy, had 9 small nodules on an irregular, hyperpigmented macule on the right shoulder. Histologically, the nodules contained nests of spindle-shaped cells in their epidermis and at the dermoepidermal junction, and the hyperpigmented macule exhibited increased melanin granules in the basal layer and small nests of epithelioid cells. We concluded that MAJM on a hyperpigmented macule is the subtype of the nevus spilus.

Humans↗
PubMed1993

Melanin repigmentation after gingivectomy: a 5-year clinical and transmission electron microscopic study in humans.

The epithelium-melanin unit is formed by the melanocytes and keratinocytes. There is little information available about the behavior of melanocytes after surgical injury. Five white patients with comparable gingival pigmentation underwent gingivectomy to remove bandlike melanin pigmentations for cosmetic reasons. Biopsy specimens were taken from gingivectomy sites and healing areas 2, 3, 6, 7, 15, 50, and 180 days and 1.5, 3, and 5 years after the procedure. Transmission electron microscopic study revealed melanocytes in the process of migration and undergoing mitosis 6 and 7 days postoperatively. These cells exhibited, in the 15-day specimens, renewal of their dendritic processes and the four different stages of melanosome development. Keratinocytes were devoid of pigmented material until 50 days postoperatively. Clinically, the intensity of the pigmentation varied among the patients. Two reached baseline coloration 1.5 years postsurgery, while three returned to baseline coloration by 3 years postsurgery. Thus, gingival resective procedures, if performed solely for cosmetic reasons, offer no permanent results. (Int J Periodont Rest Dent 1993; 13:85-92.)

Adult↗
PubMed1993

[A case of sporadic and transient bradyarrhythmias in a patient with a glioma in the medulla oblongata].

In a 20-year-old female patient with a brain stem glioma in the medulla oblongata in association with paraplegia and respiratory paralysis, bradyarrhythmias such as sinus bradycardia and sinus arrest repeated sporadically and transiently, but soon subsided as radiotherapy was being delivered to the glioma in the medulla oblongata. The bradyarrhythmias were differentiated from sick sinus syndrome in their sporadic and transient character. The patient responded normally to atropine, isoproterenol, and phenylephrine. Parasympathetic nerve reflexes induced by Aschner's, Czermak's, and Valsalva's maneuvers and sympathetic nerve reflex induced by change of body position were within normal limits. Although EKG abnormalities associated with diseases of the central nervous system are frequently due to intracranial hypertension and/or irritation of the hypothalamus, the bradyarrhythmias in this patient were possibly due to vagus stimulation caused by the glioma in the medulla.

Adult↗
PubMed1992

Lethal midline granuloma (peripheral T-cell lymphoma) after lymphomatoid papulosis.

A Japanese woman with an 8-year history of lymphomatoid papulosis (LP) had lethal midline granuloma (LMG) develop at the age of 51 years. There were histologic similarities between LP and LMG seen in this patient. Surface phenotypic studies on nasal and cutaneous lesions demonstrated a population of T-cells expressing CD2, CD4, CD25, CD30, and histocompatibility antigen-DR (HLA-DR). Genotypic analyses of nasal and skin biopsy specimens disclosed a clonal rearrangement of the beta T-cell receptor gene with the same rearrangement pattern. These data indicate that this patient had LMG characterized by clonal peripheral T-cell lymphoma, which probably resulted from progression of the LP.

Adult↗
PubMed1992

Tooth morphology following root resection procedures in maxillary first molars.

The Disto-Buccal root is the most commonly resected root in maxillary molars. This root resection procedure results in a unique environment dictated by the contours of the remaining roots and the residual furcation between them. Tooth morphology was evaluated in 50 extracted maxillary first molars after disto-buccal root resection. The following measurements were studied: 1) The maximum concavity (D) on the distal aspect of the resected molar; 2) the minimum mesio-distal dimension (d) of tooth structure between the two remaining roots; 3) the width (s) of the residual interradicular septum; and 4) the distance (p) from the pulp chamber floor to the root separation on the distal aspect of the resected molar. The mean measurements were (D) = 2.47 mm, (d) = 3.67 mm, (s) = 3.33 mm and (p) = 2.70 mm. The value of (p) was equal to or less than 3 mm in 86% of the teeth; this means that the distance from the finish line to the interradicular osseous peak is less than 2.04 mm (average biologic width), if the finish line is placed on solid tooth structure about 1 mm below the pulp floor. Six percent of the resected molars had an overall topography easily amenable to periodontal maintenance and restorative procedures with (D) less than 2 mm, (d) greater than 3 mm, (s) greater than 3 mm, and (p) greater than 3 mm. Poor root anatomy of the remaining roots after removal of the disto-buccal root in maxillary first molars may be considered as a contraindication for root resection procedures. Unfortunately, this poor topography can be ascertained only during the surgery and after removal of the disto-buccal root.

Dental Pulp Cavity↗
PubMed1992

[Gene rearrangement analysis of conjunctival malignant lymphomas].

Specific DNA probes for genes encoding immunoglobulins (Ig) and the T cell receptor (TCR) are useful diagnostic tools in lymphoproliferative disorders. Gene rearrangement analysis was carried out in 2 cases of conjunctival lymphoid lesions. A 36-year-old man (case 1) had a 1-year history of left conjunctival tumor. A biopsy was performed and histopathological findings showed diffuse proliferation of small lymphocytes, but monoclonality was not revealed by immunophenotypic analysis. A right conjunctival lesion developed and five months later a biopsy of the left conjunctiva was performed again. A frozen sample was analyzed and immunoglobulin heavy chain gene rearrangement was found. A 53-year-old woman (case 2) had a 6-month history of bilateral conjunctival tumor. The first biopsy did not reveal monoclonality immunophenotypically. A second biopsy with a frozen specimen was analyzed and immunoglobulin heavy chain gene rearrangement was found. We diagnosed these two cases as B-cell lymphoma. We discuss the clinical value of gene rearrangement analysis as a diagnostic method for lymphoproliferative disorders.

Adult↗
PubMed1990

A malignant mixed mesodermal tumor of the uterine corpus with hypercatecholaminemia.

We report an unusual case of malignant mixed mesodermal tumor of the uterine corpus associated with various symptoms related to overproduction of catecholamine by the tumor cells. Histologically, the tumor was dominated by carcinomatous epithelium with foci of malignant mesenchyma. The type of epithelium was endometrioid with papillary adenocarcinomas containing foci of malignant squamous epithelium. The malignant mesenchyma consisted mainly of a fibrous stroma with many large and bizarre cells and spindle cells mimicking leiomyosarcoma, many of which were pleomorphic and contained large bizarre hyperchromatic nuclei. Foci of atypical adult-type cartilage and neoplastic osteoid formation were noted. In the tumor tissue, membrane-bound neurosecretory-type cytoplasmic granules were demonstrated by electron microscopy and polypeptide hormone synthesis was demonstrated by immunohistochemistry. Furthermore, the patient suffered frequent attacks of sudden hypertension with hypercatecholaminemia.

Carcinoembryonic Antigen↗
PubMed1989

Electron microscopic study of the colloid-like substance in solar elastosis.

We have made electron microscopic studies on the elastotic material of solar elastosis which developed in cutis rhomboidalis nuchae taken from 10 males, 50-83 years of age. It was revealed that this material of the cutis rhomboidalis nuchae contained a colloid-like substance consisting of both a fine granular and an amorphous component. The colloid-like substance closely resembled that which is seen in the adult-type colloid milium, and could not be distinguished from it under light microscopy. In view of the morphological similarity at the ultrastructural level between the elastotic material and the colloid-like substance, it was proposed that normal elastic fibers can change into elastotic material and then further degenerate into the colloid-like substance, eventually becoming the typical colloid substance seen in colloid milium.

Aged↗
PubMed1989

[Electron microscopic and immunohistological studies of a case of Ehlers-Danlos syndrome type IV].

A 5-year-old male considered clinically to have Ehlers-Danlos syndrome (EDS) type IV with main symptoms of fragility and easy bruisability of the skin was presented. Electron microscopic observations of collagen fibers and immunohistological examination of the localization of the type III collagen in the patient revealed dissimilarities in the size and the irregularities in the shape of collagen filaments, as well as a clear difference in localization of type III collagen when compared with normal skin of same age.

Child, Preschool↗
PubMed1989

[Two cases of squamous cell carcinoma arising from erythema ab igne].

This report describes two female patients, 69 and 79 years old, with squamous cell carcinoma (SCC) developing from erythema ab igne (EAI) due to thermal irradiation from a sunken hearth (irori in Japanese) or an underfloor brazier covered with a quilt (kotatsu in Japanese). EAI on the knees and lower thighs showed reticular pigmentation at its periphery and poikiloderma in the center with many keratotic nodules. In both cases, the SCCs were located almost symmetrically on an anterior site 1/3 of the way down both lower thighs. They were surrounded by many keratotic nodules. Histologically, these nodules showed an atypia of the epidermal cells, indicating carcinoma in situ resembling actinic keratosis ro Bowen's disease. It was also strongly suggested that the SCCs in these patients had developed from the keratotic nodules. EAI appeared to have played a pathogenetic role in the cutaneous carcinoma.

Aged↗
PubMed1988

Mutational hot spots in Ig V region genes of human follicular lymphomas.

The genes coding for the Ig light chains expressed in two cases of human follicular lymphoma were cloned and sequenced. In each case, multiple independent isolates of the tumor population were compared. Although each tumor represented a single clone of B cells with a unique V/J joint, different cells within each tumor had accumulated multiple point mutations in the V gene during clonal expansion. Most of the mutations observed were silent, but some resulted in amino acid replacements. Identical silent mutations were often observed in independent isolates of each tumor. By combining the current data with VH sequences obtained previously from the same cells, it was apparent that the repetitive silent mutations could not be explained solely by a genealogic tree. Such mutations could represent hot spots whose tendency to mutate may be influenced by neighboring DNA sequences or by the methylation of specific cytosine residues.

Amino Acid Sequence↗