CHEMICAL STIMULUS DETERMINANTS OF CAT GENICULATE GANGLION CHEMORESPONSIVE GROUP II UNIT DISCHARGE

Geniculate ganglion chemoresponsive group II units were studiedin anesthetized cats. A wide variety of chemical substanceswere applied to the surface of the tongue to test for theirstimulating effectiveness. Distilled water extracts of animaltissues (beef, cod, eggs, etc.) proved to be strong stimuli.A survey of a variety of chemical subtances disclosed that themost effective excitatory stimuli were certain amino acids (L-proline,L-cysteine, L-lysine, L-histidine, etc.), di- and triphosphatenucleosides and certain other substances (usually containingnitrogen). In testing compounds related to proline and histidineit was discovered that the heterocyclic ring components pyrrolidineand imidazole were as stimulatory as the parent amino acids.To further specify the properties of excitatory stimuli manysimple heterocyclic compounds were tested. Optimum heterocyclicstimuli were four to six member nonaromatic (except for imidazole),nitrogen compounds. Neural discharge to nitrogen heterocycleswas related to two structural and chemical factors: (1) a stericfactor (in particular, ring size); and (2) the relative basicityof the compounds as indicated by pKa values. ^* This research was financed in part by USPHS Research GrantNINDS-11220 and NSF Research Grants GB-4l446X, GB-39868.     

Structure, function and phylogeny of coralinhabiting barnacles (Cirripedia, Balanoidea)

Functional morphology and cirral activity are described for two species of Armatobalanus and 15 species of pyrgomatine pyrgomatids in relation to their inhabitation of living scleractinian and hydrozoan corals. New details are given of the opercular anatomy of Megatrema anglicum. Armatobalanus allium and A. arcuatus abrade overgrowing coral coenosarc mechanically, using tergal beaks and cirri during cirral activity. Pyrgomatids erect an aperture frill (modified tergoscutal flaps). The frill is secretory and appears to be a source of chemical inhibition of coral overgrowth. Armatobalanus allium performs a strong pumping beat. Cirral activity in A. arcuatus is more varied and includes a faster dipping beat. Dipping beat is also characteristic of pyrgomatines. Opercular structure and function indicate that Armatobalanus allium, A. arcuatus, Megatrema anglicum and Cantellius euspinulosum form a functional evolutionary series, supporting the derivation of pyrgomatids from Armatobalanus. Within the genus Cantellius, a basic (type 1) and two modified (types 2 and 3) aperture frill mechanisms occur. Type 1 retains large tergal depressor muscles inserted on tergal wings on either side of the infolded aperture frill (C. euspinulosum, C. Septimus, C. gregarius). Type 2 is similar except that the muscle insertions are shifted mainly into the folds of the (larger) frill (C. pallidus, C. acutum). The type 3 frill is located more apically in a low operculum with reduced tergal depressor muscles and enlarged lateral scutal depressor muscles (C. secundus). More modified pyrgomatines can be variously derived from the three groups of Cantellius on the basis of aperture frill mechanisms, cirral activities and differences in cirral morphology. The type 1 frill occurs in Nobia projectum, N. conjugatum and Pyrgoma cancellata. The type 2 frill is strongly developed in Nobia grandis. Creusia spinulosa and four species of Savignium have a type 3 frill. The cirral activities of species with frill types 1 and 2 are based on vertical dipping beat. Species with a type 3 frill have rostrocarinal dipping beat. In Savignium milleborum this is fast beat, in S. elongatum, ‘normal’ beat, accompanied by carinal exhalent jets. Functional morphology thus reveals three main lines of evolution in the pyrgomatine pyrgomatids based on divergences within Cantellius. Each line has yielded specialized species with a fused wall and highly modified operculum, exemplified by Pyrgoma cancellata (very reduced orifice). Nobia grandis (very large aperture frill) and Savignium milleporum and S. elongatum (double adductor scutorum). Nobia and Savignium as previously defined are polyphyletic. Four new genera are proposed. The evolution of an aperture frill and chemical inhibition of coral overgrowth is associated with a reduced orifice and often a reduced cirral fan. In some species there may be nutrient uptake from the coral host, but experimental tests are needed.     

The use of an automated image cytometer for screening and quantitative assessment of cervical lesions in the British Columbia Cervical Smear Screening Programme

The use of an automated image cytometer for screeing and quantitative assessment of cervical lesions in the British Columbia Cervical Smear Screening Programme
The development of an automated device to screen cervical cytology slides for the detection of pre-invasive lesions of the cervix has been the goal of many individuals for over 30 years. The increasing sophistication of the technology of automation and increasingly powerful computer technology have enabled a number of these systems to reach the stage at which they have become a practical reality. The Department of Cancer Imaging at the British Columbia Cancer Agency has developed such a device over the past few years. This study reports the preliminary results of a trial to determine the reliability of the device for the screening and quantitative assessment of cervical cells. A training set of over 1000 cervical slides was used to train the image cytometer. A test set of 1030 slides was screened by the image cytometer and in the Cytology Screening Laboratory. At the 50% sample split the sensitivity of the image cytometer was 95% for severe dysplasia and 90% for moderate dysplasia, compared with a sensitivity of 90% for both of these lesions using conventional screening. A combination of nuclear texture features was found which can be used for the quantitative assessment of both abnormal cells and apparently normal intermediate cells.