PubMed Health⌕ Search

Biomedical subjects

C D Fermin

Publications and source records attributed to C D Fermin.

9 recordsLinked to original sources
PubMed1992

Membrane alterations linked to early interactions of HIV with the cell surface.

Ultrastructural studies suggest that cell surface alterations occur early during the course of HIV-1 infection of CD4+T-lymphoblastoid cells. Attachment and penetration of HIV resulted in formation of membrane discontinuities and pores and "ballooning." Distention of the endoplasmic reticulum occurred in some cells within the first hour after HIV infection, and this correlated with the numbers of virions bound at the cell surface. These results suggest that HIV virion components may directly damage the cell membrane.

CD4-Positive T-Lymphocytes↗
PubMed1992

Colour thresholding and objective quantification in bioimaging.

Computer imaging is rapidly becoming an indispensable tool for the quantification of variables in research and medicine. Whilst its use in medicine has largely been limited to qualitative observations, imaging in applied basic sciences, medical research and biotechnology demands objective quantification of the variables in question. In black and white densitometry (0-256 levels of intensity) the separation of subtle differences between closely related hues from stains is sometimes very difficult. True-colour and real-time video microscopy analysis offer choices not previously available with monochrome systems. In this paper we demonstrate the usefulness of colour thresholding, which has so far proven indispensable for proper objective quantification of the products of histochemical reactions and/or subtle differences in tissue and cells. In addition, we provide interested, but untrained readers with basic information that may assist decisions regarding the most suitable set-up for a project under consideration. Data from projects in progress at Tulane are shown to illustrate the advantage of colour thresholding over monochrome densitometry and for objective quantification of subtle colour differences between experimental and control samples.

Animals↗
PubMed1992

Development of the endolymphatic sac in chick embryos, with reference to the degradation of otoconia.

The endolymphatic sac of chick embryos (from embryonic day 7 to 1-day-old chicks) was studied light- and electron-microscopically. At stage 30-31 (embryonic day 7-7.5), the epithelial cells of the endolymphatic sac were cuboidal to columnar in shape. Microvilli were relatively well developed. The intercellular space was wide. In the endolymphatic space of the endolymphatic sac, varying shapes and sizes of otoconia-like bodies were often observed. Intracytoplasmic phagosomes containing these bodies were rarely found. After stage 37 (embryonic day 11), otoconia-like bodies in the endolymphatic sac decreased in number and size. They were almost the same as the otoconia in the macular organs, ultrastructurally. These findings indicate that the endolymphatic sac of the chick embryos may possess the function of otoconial degradation and removal of calcium from otoconia.

Animals↗
PubMed1990

Detection of a human intracisternal A-type retroviral particle antigenically related to HIV.

Sjögren's syndrome is an autoimmune disease that is characterized by dryness of the mouth and eyes. The loss of salivary and lacrimal gland function is accompanied by lymphocytic infiltration. Because similar symptoms and glandular pathology are observed in certain persons infected with human immunodeficiency virus (HIV), a search was initiated for a possible retroviral etiology in this syndrome. A human intracisternal A-type retroviral particle that is antigenically related to HIV was detected in lymphoblastoid cells exposed to homogenates of salivary tissue from patients with Sjögren's syndrome. Comparison of this retroviral particle to HIV indicates that they are distinguishable by several ultrastructural, physical, and enzymatic criteria.

Centrifugation, Density Gradient↗
PubMed1990

Fast processing of black and white films used in the EM lab.

Kodak black and white film emulsions 4489, 4162, 2415, TMAX-100, TMAX-400, MPD-4 and RPC-651 can be developed in less than 10 minutes on a film processor, quickly printed on resin coated paper and dried with auto-processor and dryer. Adjustments to the ASA (ISO) to compensate for increased contrast with auto-processing are described.

Microscopy, Electron↗
PubMedDate not supplied

Immunohistochemical localization of the neuropeptide, pituitary adenylate cyclase activating polypeptide (PACAP), in human and primate hypothalamus.

A 38 residue neuropeptide was recently isolated from ovine hypothalamus in our laboratory, and named pituitary adenylate cyclase activating polypeptide (PACAP38) based on its biological activity. Rabbit antisera against synthetic PACAP27 were characterized by ELISA for immunohistochemical use. PACAP-immunoreactive neuronal elements having similar distributions were demonstrated in both human and spider monkey hypothalami. Many PACAP-immunoreactive cell bodies were present in the supraoptic and paraventricular nuclei. Immunopositive nerve fiber networks were stained throughout the hypothalamus, including in both external and internal zones of the tuber cinereum, close to the transition of the pituitary stalk (median eminence). These results suggest that PACAP plays multifunctional roles as a hypophysiotropic hormone, neurohypophysial hormone, neurotransmitter or neuromodulator in higher vertebrate species including man.

Amino Acid Sequence↗
PubMedDate not supplied

The development of hair cells in the embryonic chick's basilar papilla.

During the 7th to 21st (hatching) days, hair cells of the embeyonic chick transform from an undifferentiated epithelium into cylindrically-shaped tall hair cells (THCs), pitcher-shaped short hair cells (SHCs), or intermediate hair cells that share structural characteristics of the first two. By the 11th day hair cell types are unambiguous. "Hairs" (stereocilia and a kinocilium) were first identified on the 7th day and resembled the adult pattern the 13th. The nucleus occupies relatively less volume as hair cells increase in size, becoming positioned centrally in THCs and basally in SHCs. Nucleoli, which are prominent throughout development, remain conspicuous even in newly hatched chicks. The cuticular cone begins to form the 11th day. By the 10th day, sensory nerve endings synapse on the bases of the HCs, which by the 11th day develop synaptic bars. Although efferent neurites were in evidence as early as the 11th day, synaptic contacts and their cisterns were identified by the 19th day but may form earlier. Supporting cells transform from cylindrically to flask-shaped cells with constricted necks and may secrete at least a portion of the tectorial membrane.

Afferent Pathways↗
PubMedDate not supplied

Ultracytochemical localization of Na+, K(+)-ATPase activity in the tegmentum vasculosum of the developing chick cochlea.

We studied the morphological changes and the precise localization of Na+, K(+)-ATPase activity in the developing chick tegmentum vasculosum (TV) with a cytochemical method utilizing K(+)-p-nitrophenylphosphatase (K(+)-NPPase). At stage 37, epithelial folds (lamellae) were relatively well developed, and the light and the dark cells were clearly identified. At stage 41 to 42, Na+, K(+)-ATPase activity appeared in the folded cytoplasmic processes of the dark cells which interdigitated with those of the light cells. The present results indicate that the TV is involved in the production of the cochlear endolymph prenatally (at least up to stage 41), and that the dark cell plays a central role in the maintenance of the ionic composition of the endolymph.

Animals↗