PubMed Health⌕ Search

Biomedical subjects

C J Witkop

Publications and source records attributed to C J Witkop.

At least 55 records · Page 3Linked to original sources
PubMed1979

The presence of Candida albicans in hereditary benign intraepithelial dyskeratosis. An ultrastructural observation.

Specimens taken from the buccal mucosa of two patients with hereditary benign intraepithelial dyskeratosis (HBID) were studied by transmission electron microscopy. The ultrastructure of epithelial tissue in HBID was previously reported. Discovery of Candida albicans in this lesion was an accidental finding. The literature on the subject was reviewed and the ultrastructural features of Candida albicans were described.

Adolescent↗
PubMed1979

Chromosome breaks and sister chromatid exchanges in albinos in Nigeria.

The prevalence of squamous cell carcinoma of the skin in albinos reaches approximately 90% in patients over 20 years of age in the vicinity of Enugu, Nigeria. Chromosome breaks and sister chromatid exchanges (SCE) were evaluated in tyrosinase-positive oculocutaneous albinos and pigmented controls of Ibo extraction who were life-long residents of Nigeria. No difference in the frequency of chromosomal breaks in 14 albinos compared to 6 pigmented controls, and no differences in the frequency of SCE in 9 albinos compared to 3 controls could be detected. Increased chromosomal abnormalities in lymphocytes do not appear to be assoicated with albinism or fulminating skin cancer present in albinos in the tropics.

Adolescent↗
PubMed1979

Hereditary mucoepithelial dysplasia: a disease apparently of desmosome and gap junction formation.

A previously unrecognized autosomal dominant syndrome affecting oral, nasal, vaginal, urethral, anal, bladder, and conjunctival mucosa with cataracts, follicular keratosis, nonscarring alopecia, and terminal lung disease is described in a four-generation kindred of German extraction. Severe photophobia, tearing, and nystagmus in infancy heralds the development of keratitis, corneal vascularization, and lens cataracts. Repeated corneal transplants have failed. Red, periorificial mucosal lesions involving the above structures are noted by 1 year of age and may persist throughout life. Chronic rhinorrhea and repeated upper respiratory infections frequently progress to bilateral pneumonia accompanied by loss of hair, diarrhea, occasional melena, enuresis, pyuria, and hematuria. Spontaneous pneumothorax is frequent, terminating in fibrocystic-type lung disease and cor pulmonale. Women have had repeated abnormal vaginal PAP smears. Histologically the mucosal epithelium shows dyshesion, thinning of the epithelial layer, and dyskeratosis. Mucosal PAP smears show lack of epithelial maturation, cytoplasmic vacuoles and inclusions, and individual cell dyskeratosis. Histochemically there is a lack of cornification and keratinization. Ultrastructural studies show lack of keratohyalin granules, a paucity of desmosomes, intercellular accumulations, cytoplasmic vacuolization, and formation of bands and aggregates of filamentous fibers and structures in the cytoplasm resembling desmosomes and gap junctions. The condition is probably a panepithelial cell defect of desmosomal and gap junction structure most prominently affecting mucosal epithelia associated with an increased susceptibility to a variety of adventitious organisms.

Adult↗
PubMed1978

Visual system anomalies in human ocular albinos.

Visually evoked potentials recorded from two types of human ocular albinos demonstrated significant hemispheric asymmetry following monocular stimulation. The asymmetry is indicative of disorganization of retinogeniculostriate projections similar to that reported for mammals with total albinism. Abnormal optic projections are associated with lack of ocular pigment and are not associated with any specific generalized pigment defect.

Albinism↗
PubMed1978

Autosomal recessively inherited ocular albinism. A new form of ocular albinism affecting females as severely as males.

A new form of ocular albinism, autosomal recessively inherited ocular albinism (AROA), was studied in seven females and two males from five unrelated Caucasian kindreds. Affected patients have the impaired vision, translucent irides, congenital nystagmus, photophobia, albinotic fundi with hypoplasia of the fovea, and strabismus that are also found in X-linked ocular albinism (XOA). Unlike XOA, however, this form of ocular albinism is inherited as an autosomal recessive trait, with females affected as severely as males. Obligate heterozygotes of AROA lack the ocular abnormalities that are present in females heterozygous for XOA. Also, skin and hairbulb biopsy specimens do not reveal any abnormalities in patients with AROA, whereas giant pigment granules are found in patients heterozygous and hemizygous for XOA. The recognition of this disorder is imperative for proper diagnosis and responsible genetic counseling.

Adult↗
PubMed1978

Clinical, genetic, and histologic features of the trichoonychodental (TOD) syndrome.

A syndrome of scanty, fine, curled hair, thin dysplastic nails, taurodontic molars, hypoplastic-hypomature enamel, dysplasia of dentin, and hypohidrosis segregating as an autosomal dominant trait is described in a Japanese family. The patients received repeated doses of tetracycline during odontogenesis which fortuitously assisted in interpreting the pathogenesis of the dentin defect. The condition was previously described as familial congenital ectodermal dysplasia by Westerholm and as odontogenesis imperfecta by Siirilä and Heikinheimo. It is suggested that the name trichoonychodental (TOD) syndrome is a better descriptive term for the condition.

Chromosome Aberrations↗
PubMed1978

Clinical, histologic, cytologic, and ultrastructural characteristics of the oral lesions from hereditary mucoepithelial dysplasia. A disease of gap junction and desmosome formation.

Hereditary mucoepithelial dysplasia is an autosomal, dominantly inherited disorder affecting all of the orificial mucosa with cataracts, follicular keratosis of skin, nonscarring alopecia, bouts of pneumonia, spontaneous pneumothorax, and terminal cor pulmonale. The oral lesion is a fiery red, flat or micropapillary-appearing mucosa most frequently involving the gingiva and hard palate. All oral and pharyngeal mucosa may be involved, however. Red scrotal mucosa of the tongue is common. Histologically, the oral mucosa shows a lack of cornified and keratinized cells, a decrease in the thickness of the epithelial cell layer, dyshesion, and dyskeratosis. Papanicolaou smears show lack of epithelial cell maturation, poikilocytosis, anisocytosis, large paranuclear cytoplasmic vacuoles, and cytoplasmic strand-shaped inclusions. Ultrastructural features include a paucity of desmosomes, intercellular accumulations of amorphous material, cytoplasmic vacuoles, and paranuclear lesions with strands of material resembling gap junctions and desmosomes. The condition most likely represents a basic defect in gap junction and desmosome formation.

Adult↗
PubMed1978

Odontodysplasia. Report of three cases with vascular nevi overlying the adjacent skin of the face.

Three cases of odontodysplasia are described, and the literature is reviewed with reference to proposed etiologic mechanisms underlying the pathogenesis of the disorder. The distribution of affected teeth in all four quadrants of one patient is offered as evidence against a somatic mutation as an etiologic mechanism. As infants all three patients had vascular nevi in the facial skin overlying the area where defective teeth developed. Three cases from the literature involved similar vascular lesions. Hypoplastic teeth radiographically similar to odontodysplastic teeth occur in the linear sebaceous nevus syndrome. These findings strongly suggest that local vascular defects are involved in the pathogenesis of odontodysplasia.

Child↗
PubMed1978

Characterization of human hairbulb tyrosinase: properties of normal and albino enzyme.

Human hairbulb tyrosinase from normally pigmented and tyrosinase-positive oculocutaneous albino (TPA) hairbulbs was studied by single hairbulb and by pooled hairbulb assay procedures. The response to temperature and pH was the same for TPA and normal enzyme. The Km for tyrosine as substrate and the Km or dopa as cofactor was the same for TPA and normal enzyme. These studies show that TPA tyrosinase is kinetically normal and that the defect with this form of albinism must be elsewhere in the melanin pathway.

Albinism↗
PubMed1977

Ultrastructural study of hereditary benign intraepithelial dyskeratosis.

Specimens taken from the buccal mucosa of two patients with hereditary benign intraepithelial dyskeratosis (HBID) were studied with the transmission electron microscope. Ultrastructural features were described and compared with those of white sponge nevus and Darier's disease. Ultrastructural findings in HBID revealed the presence of numerous vesicular bodies in immature dyskeratotic cells, densely packed tonofilaments filling the cytoplasm of mature dyskeratotic cells, and the disappearance of cellular interdigitations and desmosomes in mature dyskeratotic cells.

Adolescent↗
PubMed1977

Detection of heterozygotes for tyrosinase-negative oculocutaneous albinism by hairbulb tyrosinase assay.

Five heterozygotes for ty-neg OCA had absent or markedly reduced hairbulb tyrosinase activity, when compared to normally pigmented control subjects. Clinically, all five were fully pigmented and could not be distinguished from the normal control subjects. It is proposed that the quantitative hairbulb tyrosinase assay can be used to detect heterozygotes for ty-neg OCA. A mechanism to explain the low levels of activity in the hairbulbs from heterozygotes is discussed.

Albinism↗
PubMed1977

The influence of prostaglandin G2 on platelet ultrastructure and platelet secretion.

Prostaglandin G2 (PGG2) is a labile endoperoxide produced physiologically following exposure of platelets to aggregating agents. We report here studies using isolated PGG2. This agent stimulates a concentration-dependent internal platelet contraction very similar to that produced by the calcium ionophore A23187. EDTA prevented platelet aggregation but did not prevent PGG2-stimulated internal contraction or secretion. In contrast, prostaglandin E1 and dibutyryl cyclic AMP inhich selectively labilizes platelet granules, was added to platelets together with PGG2 there was a superadditive effect on platelet secretion. Thus, granule labilization induced by PMA is a separable phenomenon and complementary to the effect of PGG2 on contraction. The ultimate degree of secretion is dependent on both processes. Studies using additional inhibitors supported the hypothesis that PGG2 activates platelets (either directly or following conversion to thromboxane A2) by transporting calcium from an intracellular store to the cytoplasmic site of the platelet contractile proteins.

Adenosine↗
PubMed1977

[Globodontia--a new familial tooth abnormality].

A new, congenital anomaly of tooth form transmitted as an autosomal dominant trait was found in a father and two of his three sons. While the incisors appeared unchanged, the posterior teeth have characteristic massive globe-shaped crowns with irregularly arranged, rounded cusps. The occlusal surfaces resemble in their extreme form the underside of a tomato. The relation to the otodental syndrome is not clear as yet.

Adult↗
PubMed1977

The Hermansky-Pudlak syndrome. Evidence for a lowered 5-hydroxytryptamine content in platelets of heterozygotes.

A Dutch kindred with the Hermansky-Pudlak syndrome (HPS) is described. We show for the first time evidence of a lowered platelet 5-hydroxytryptamine content in obligate heterozygotes. Platelet ATP and ADP levels and ATP/ADP ratio were normal in these patients. Platelet aggregation with ADP, collagen and adrenaline was within the normal range. In contrast to the homozygous HPS patients the heterozygotes are normally pigmented and none has diaphanous irides, nystagmus or a bleeding tendency. All homozygous HPS patients have the typical triad of oculocutaneous albinism, pigmented macrophages in the bone marrow and a bleeding disorder, based on a platelet dysfunction. The platelets showed the typical characteristics of a storage pool deficiency. Their platelet factor 3 availability was decreased and the aggregation patterns showed an absent second wave with ADP, adrenaline and absent collagen aggregation. Platelet ADP levels were strongly decreased in all homozygous HPS patients, whereas ATP was lowered only in 3 out of 6 HPS patients. The 5-hydroxytryptamine content of their platelets was very low (15-20% of normal).

Adenosine Diphosphate↗