Proposed form to evaluate some histological aspects of macrofilarial morphology, its age dependent alterations and drug related changes in nodules of Onchocerca volvulus and O. gibsoni.
Histological assessment of drug-related pathomorphological changes in macrofilariae of the two nodule forming species Onchocerca gibsoni and O. volvulus is hampered by the variability of age-dependent signs of natural degeneration and the virtual inexistence of clinically established reference medicaments. A specific form was designed to record systematically all characteristics observed in the various organs, tissues, cell types and developmental stages inside normal and drug-affected macrofilariae. Its tabular format permits the synoptic presentation of the findings in all female and male macrofilariae from a particular treated or untreated individual. The proposed form enumerates thirty eight morphological characteristics subdivided into the six subunits cuticle, hypodermis, longitudinal muscle, genital tract, pseudocoelomic cavity and intestinal tract (gut). The normal morphology of sexually mature and productive male and female O. volvulus is described and illustrated by photomicrographs. The cuticle of the male is wrinkled and forms regular striations strictly transverse to the body's longitudinal axis. The longitudinal muscles are well developed and cover almost 100% of the circumference at the anterior and posterior end. Towards the mid-body region the muscular portion diminishes to 50-60% and is replaced there by the very voluminous lateral hypodermic chords. The male genital tract originates with its distal end of the testis close to the anterior end and runs through almost the entire body very close to the posterior end. Spermatogenesis is clearly synchronized and the various development stages are arranged in strict sequential order inside the genital tract. Each type of gonosomal cell may thus serve as a marker of the respective region of the body. The same applies for females where the paired genital tubes run through almost the entire length of the body until the two uteri unite to form a short unpaired vagina. Each of the two reproductive tracts originates at different levels in the posterior part of the female. Because of this, two distinct stages of the sexual products are normally present in sections of the two uteri in the various parts of the female macrofilariae. Towards the anterior end identical stages of embryos may be found. The wide uteri narrow shortly before the vaginal junction to less than 40 microns in the very anterior part of the body. This part is characterized by the voluminous lateral chords of hypodermis and the well developed longitudinal muscles covering greater than 50% of the circumference. Drug-related changes come to light first in this part of the female's body.(ABSTRACT TRUNCATED AT 400 WORDS)
Striebel
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HP
Pharma International Medicine, CIBA-GEIGY Limited, Basel, Switzerland.
D000375:Aging; D000818:Animals; D000871:Anthelmintics / Q000494:pharmacology / Q000627:therapeutic use; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy / Q000469:parasitology; D005260:Female; D006801:Humans; D008297:Male; D009854:Onchocerca / Q000033:anatomy & histology* / Q000187:drug effects; D009855:Onchocerciasis / Q000188:drug therapy / Q000469:parasitology* / Q000662:veterinary; D012727:Sex Characteristics
D000871:Anthelmintics