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Biomedical subjects

C J Witkop

Publications and source records attributed to C J Witkop.

At least 73 records · Page 4Linked to original sources
PubMed1976

Globodontia in the otodental syndrome.

A family of Polish extraction was studied in which massive, globe-shaped posterior teeth were found in a father and two of his sons, similar to those described in a previous family in which persons with this type of teeth also had a high-frequency sensorineural deafness. The audiograms in this family showed high-frequency air-conduction thresholds in the father and one son with globodontia and in other relatives without the tooth defect. The other son with abnormal teeth had a normal-appearing audiogram. Absence of premolar teeth and yellow-white spots of local hypomaturation of enamel on canine teeth were also findings in this kindred, as reported or observed in other kindreds. The disorder illustrates the problem of variable expressivity of a trait which makes it difficult to predict the risk of having an affected child when only one feature of a syndrome is present in a relative of a fully affected patient.

Adult↗
PubMed1976

Psychosocial factors in low-incidence genetic disease: the case of osteogenesis imperfecta.

Osteogenesis imperfecta (OI), a dominant genetic disorder, was examined in an exploratory case study of psychosocial implications. The cross-sectional survey sample consisted of 13 OI-affected adults and 21 families with an OI-affected child who were interviewed. Findings revealed numerous psychosocial concerns and problems in addition to their complex and lifelong medical problems. Specific problem areas differed according to the severity of the disease, type, and mode of genetic inheritance. The results indicate the need for local as well as national policy changes through legislation and extensions of existing services for low-incidence disease groups such as OI-affected persons. Implications for social work practice interventions call for greater involvement with genetic diseases, more aggressive approaches in case identification and service coordination, and performing longer-range monitoring functions than is usually the case.

Adult↗
PubMed1976

An improved method for the extraction of endogenous platelet serotonin.

Investigations of blood platelet serotonin content, turnover, metabolism, and secretion require sensitive methods for accurate measurement of the amine. The present study has sought a simple, efficient procedure for extracting total platelet serotonin which could also be used for analysis of other platelet chemical constituents. ZnSO4 precipitation, the standard technique for extracting 5-HT, failed to recover total platelet serotonin despite physical and chemical manipulations to improve its availability. Perchloric acid extraction was found to be more efficient, resulting in significantly increased values for endogenous platelet serotonin and recovery of 97 per cent of standard amounts of 5-HT added to platelet pellets. In addition, the perchloric acid extracts could be used for analysis of other platelet constituents such as adenine nucleotides. The improved procedure eliminates the need for large numbers of replicate samples for several assays and, at the same time, provides a more sensitive method for recovery of total platelet serotonin. It may also prove valuable for prolonged in vitro experiments in which extraction must be followed by additional isolation procedures in order to separate indole metabolites of serotonin from the amine for specific quantitation.

Adult↗
PubMed1976

Clinical aspects of dental anomalies.

Many inherited disorders have oral manifestations which can be detected on dental radiographs as alterations in the morphology or chemical composition of the teeth. Thus the dentist may be the first to detect disorders of development and metabolism of importance to the general health of the patient and his family. In one group of conditions the pulp chamber is larger than normal. This may be associated with taurodontism in such conditions as polyploidy of the -X chromosome and trisomy-21 or Down's syndrome. Taurodontism also occurs in a variety of other syndromes including the tricho-dento-osseous syndrome described by Robinson, Miller and Worth (1966) and Mohr's syndrome. It may also be associated with scanty hair endoligodentia. In certain metabolic conditions the pulp chamber may be enlarged but the teeth are of relatively normal from (cynodont). Such cases include hypophosphatemic vitamin D-resistant and dependent rickets, pseudo-hypoparthyroidism otodental syndrome and hypophosphatasia. Small pulp chambers and associated anomalies of root morphology also occur in hereditary disorders either alone or as part of various syndromes such as dentino-osseous dysplasia and brackioskeletogenital syndrome. Dentinogenesis imperfecta may occur alone or as one manifestation of osteogenesis imperfecta. Other developmental defects including pulpal dysplasia, labodontia and dens invaginatus are also associated with small pulp chambers.

Bone Diseases, Developmental↗
PubMed1975

Influence of prostaglandins E1, E2, and arachidonate on melanosomes in melanocytes and keratinocytes of anagen hair bulbs in vitro.

Anagen hair bulbs were collected and maintained in organ culture for periods up to 24 hr. Prostaglandin E1, E2 and arachidonate were introduced to the cultures and stimulated a series of cellular events characterized by peripheral orientation of microfilaments in the dendritic processes of melanocytes, complexing of melanosomes; and degradation of melanosomes within keratinocytes. These events were dependent on the concentration of prostaglandins. In addition, the most potent agent for these events was arachidonate. The action of arachidonate was hypothesized to occur through the production of endogenous prostaglandins since arachidonate was ineffective in the presence of inhibitors of prostaglandin synthetase.

Arachidonic Acids↗
PubMed1975

Labile aggregation stimulating substance (LASS): the factor from storage pool deficient platelets correcting defective aggregation and release of aspirin treated normal platelets.

Mixtures of equal volumes of Hermansky-Pudlak (HP) syndrome (adenine nucleotide storage pool deficient) and aspirin treated (AT) platelets (inhibited release of adenine nucleotides) undergo irreversible aggregation when exposed to collagen or adrenaline, whereas neither alone will do so. The present investigation has explored the basis for the mutual correction. Correction in the mixed system was accompanied by release of significant amounts of [14C]5-hydroxy-tryptamine from the AT platelets, whereas very little isotope was released when AT platelets alone were exposed to collagen. The correction of aggregation and the release of isotope could both be suppressed by pre-treating HP platelets with aspirin. Labile aggregation stimulating substance (LASS) composed of two closely linked intermediates of prostaglandin (PG) E2 and PGF2alpha biosynthesis, produced using a microsomal fraction of HP platelets, could correct the aggregation and secretion defect of AT platelets exposed to collagen. These findings indicate that HP platelets when mixed with AT platelets and exposed to collagen secrete a substance which is responsible for the correction. LASS, identified as the factor involved, acted as an intercellular messenger which mediated the correction by overcoming the influence of aspirin on normal cells.

Adenine Nucleotides↗
PubMed1975

The Saethre-Chotzen syndrome.

The Saethre-Chotzen Syndrome (SCS) is characterized by craniosynostosis, low-set frontal hairline, parrot-beaked nose with deviated septum, ptosis of the eyelids, strabismus, refractive error, tear duct stenosis, dystopia canthorum, brachydactyly and abnormal dermatoglyphic patterns. The syndrome follows an autosomal dominant mode of transmission with complete penetrance and variable expressivity. Many cases of SCS have been previously reported but erroneously diagnosed as Crouzon syndrome, "pseudo-Crouzon" syndrome, simple craniosynostis, microcephaly or other inappropriate diagnostic category. Based on the findings in 6 kindreds with 31 affected individuals and an analysis of well-documented cases from the literature, the syndrome is delineated. Close attention to minor skeletal anomalies and "incidental" findings is emphasized.

Abnormalities, Multiple↗
PubMed1975

Alteration in the surface morphology of synchronized B-16 melanoma cell during the cell cycle.

B-16 melanoma cells were synchronized for G1-S periods by mitotic shake-off and S-G2 periods by thymidine block. The surface morphology of the B-16 melanoma at low density partially confluent culures revealed that, as in other cell systems investigated, the surface morphology could be correlated with four periods to cell cycle: G1, S, G2 and M. G1 cells were rounded and possessed microvilli, blebs and ruffles (late G1). During S period, blebs and microvilli diminished and disappeared, but ruffles were more evident. Late G2 cells acquired microvilli, surface blebs, and extended filopodia and began to thicken and round themselves for mitosis.

Animals↗