Post-vasectomy autoimmunity to protamines in relation to the formation of granulomas and sperm agglutinating antibodies. (41/4345)

The development of antibodies reacting with nuclear antigens was studied in sera from vasectomized men and monkeys (obtained at intervals of up to 2 and 4 years, respectively, after the operation), by means of a comparative fluorescence study on swollen nuclei of somatic cells, human and salmon spermatozoa. About 30% of forty-seven vasectomized men developed antibodies to protamines. Also four out of fifteen monkeys, vasectomized with or without ligation, developed antibodies reacting with protamines. In general, when antibodies to the homologous protamines reached higher levels, cross-reactions with salmon protamine could be demonstrated as well. No significant reactions could be detected with somatic nuclear antigens in the sera. Comparison between the results obtained with the immunofluorescence test, the agglutination tests and the clinical findings confirmed the association between the development of immune responses to various sperm-antigens and revealed a coherence of anti-protamine activity and granuloma formation at the site of the operation.  (+info)

Operant methodology in the study of learning. (42/4345)

A series of experiments is described in which operant methodology is used to study the effects of drugs on "learning." Emphasis is placed on the technique of repeated acquisition as a behavioral baseline for studying this type of transition state. In this technique, each subject is required to learn a new discrimination each session. Multiple-schedule procedures are also described in which acquisition is compared to a "performance" task, where the discrimination is the same each session. The learning baseline is more sensitive to the disruptive effects of a variety of drugs (e.g., cocaine, d-amphetamine, haloperidol) than is the performance baseline. This general finding obtains across procedural variations and species (pigeons and monkeys). The potential usefulness of these procedures for studying both acute and chronic behavioral toxicity is discussed.  (+info)

Chloroquine retinopathy in the rhesus monkey. (43/4345)

Chloroquine was administered intramuscularly 5 days a week to rhesus monkeys for as long as 4 1/2 years. No clinical, fluorescein angiographic, or electrophysiological evidence of retinal damage was observed. Yet chloroquine/chloroquine byproduct analysis of the ocular tissues revealed an enormous binding capacity of the pigmented tissues of the eye (choroid plus RPE, ciliary body, and iris) with eventual accumulation observed in the retina. Despite the normal ophthalmic appearance and function, extensive pathological changes occurred in the retinas and choroids of these experimental monkeys. The chloroquine caused an initial dramatic effect on the ganglion cells, with the photoreceptors affected shortly thereafter. Patching degeneration of the ganglion cells and photoreceptors then progressed over several years, with the choroid and pigment epithelium ultimately deteriorating as well.  (+info)

The distribution of the chorda tympani in the middle ear area in man and two other primates. (44/4345)

A serial section study of the distribution of the chorda tympani in the middle ear area was carried out in man, baboon and monkey. The tissues innervated by the chorda tympani could be related to a branchiomeric pattern. The early branches distributed post-trematic facial nerve fibres to hyoid arch tissues, where they were joined by elements from glossopharyngeal and vagus nerves. The rest of the distribution was to structures derived from mandibular arch tissue where branches of the auriculotemporal nerve were also present. Contributions to perivascular plexuses were noted as well as a connexion with the otic ganglion.  (+info)

The effect of miotics on the intraocular pressure of conscious owl monkeys. (45/4345)

The intraocular pressure of conscious, unsedated owl monkeys (Aotus trivirgatus) was measured with an applanation tonometer. Untreated eyes of the conscious animals were found to have higher values than those reported for owl monkeys anesthetized with pentobarbitone. Locally applied pilocarpine, carbachol, and oxotremorine gave concentration-related reduction in pressure, oxotremorine being the most potent and having longer duration of effect than the other compounds. Slight reductions were also observed with aceclidine and R. S. 86. These results are discussed in relation to the effects of miotics in man.  (+info)

Malaria immunization in Rhesus monkeys. A vaccine effective against both the sexual and asexual stages of Plasmodium knowlesi. (46/4345)

Rhesus monkeys were immunized with a preparation of Plasmodium knowlesi parasites containing principally microgametes with lesser numbers of macrogametes and asexual trophozoites. The antigen mixture was emulsified in Freund's complete adjuvant (FCA) and administered intramuscularly. After one or two inoculations of from 10(5) to 10(7) microgametes in FCA, monkeys showed high levels of circulating anti-gamete antibodies as demonstrated by various in vitro microgamete immobilization or transmission blocking tests. After challenge with P. knowlesi, immunized monkeys developed low level asexual parasitemias and were not infectious to feeding mosquitoes as measured by growth of the parasite on the mosquito gut. Control monkeys developed rapidly rising, usually fatal infections and were highly infectious to mosquitoes. Anti-gamete antibodies appear to neutralize the sexual parasites and prevent mosquito infection within the gut of the recently fed mosquito vector. Suppression of asexual parasitemia in immunized monkeys may be due to the presence of asexual trophozoites in the antigen mixture or to antigens common to both sexual and asexual stages of the parasite. A vaccine effective as a single injection capable of interrupting malaria transmission from man to man whereas reducing the severity of the disease in infected individuals offers a new approach to the control of one of the major diseases affecting man.  (+info)

The physiological effects of monocular deprivation and their reversal in the monkey's visual cortex. (47/4345)

1. 1127 single units were recorded during oblique penetrations in area 17 of one normal, three monocularly deprived and four reverse sutured monkeys. 2. In all animals most cells outside layer IV c were orientation-selective, and preferred orientation usually shifted from cell to cell in a regular progressive sequence. 3. The presence in layer IV c of non-oriented, monocularly driven units, organized in alternating right-eye and left-eye 'stripes' (LeVay, Hubel & Wiesel, 1975) was confirmed. 4. Early monocular deprivation (2--5 1/2 weeks) caused a strong shift of ocular dominance towards the non-deprived eye. However, even outside layer IV c, neural background and some isolated cells could still be driven from the deprived eye in regularly spaced, narrow columnar regions. In layer IV c the non-deprived eye's stripes were almost three times wider, on average, than the deprived. 5. Later monocular deprivation (11--16 months) had no detectable influence on layer IV c but seemed to cause a small shift in ocular dominance outside IV c. Deprivation for 6 1/4 months in an adult had no such effect. 6. After early reverse suturing (at 5 1/2 weeks) the originally deprived eye gained dominance over cells outside layer IV c just as complete as that originally exercised by the eye that was first non-deprived. 7. The later reverse suturing was delayed, the less effective was recapture by the originally deprived eye. Reversal at 8 weeks led to roughly equal numbers of cells being dominated by each eye; fewer cells became dominated by the newly open eye after reverse suturing at 9 weeks and most of them were non-oriented; reversal at 38 1/2 weeks had no effect. 8. Binocular cells, though rare in reverse sutured animals, always had very similar preferred orientations in the two eyes. The columnar sequences of preferred orientation were not interrupted at the borders of ocular dominance columns. 9. Even within layer IV c there was evidence for re-expansion of physiologically determined ocular dominance stripes. After early reverse suture, stripes for the two eyes became roughly equal in width. Possible mechanisms for these changes are discussed.  (+info)

Movement-sensitive and direction and orientation-selective cutaneous receptive fields in the hand area of the post-central gyrus in monkeys. (48/4345)

1. In the hand area of the post-central gyrus of three alert Macaca speciosa monkeys neurones related to cutaneous receptors but not activated by simple touch on the receptive field were recorded using the transdural micro-electrode recording technique. Thirty-six cells were found to have complex cutaneous receptive field properties. These neurones were subdivided into the following three groups. 2. Nine neurones were not activated by punctate stimuli on the receptive fields but responded well to movement along the skin. The activity of these neurones was not affected by the direction of movement; nor was it sensitive to different textures of the moving surface. 3. Eighteen neurones responded to cutaneous movement along the skin surface in a particular direction giving no response to stimulation in the opposite direction and intermediate responses to intermediate directions. Similar responses were evoked from different subparts of the receptive field. 4. Nine neurones responded well to an edge placed on the skin in an optimal orientation or moved along the skin in a direction perpendicular to the edge. A maximal response was produced by stimuli of the same optimal orientation in different parts of the receptive field. The significance of the stimuli to the monkey had only a minor influence on the magnitude of the responses of these neurones and no influence on the receptive field properties. 5. The occurrence of the complex cutaneous cells increased from anterior to posterior within the post-central gyrus and most of them were found in Brodmann's area 2. Thus we postulate that the complex receptive field properties arise as a consequence of cortical processing in a network in which postsynaptic one-way lateral inhibition generates the directional properties of the neurones. 6. The complex cutaneous neurones constituted only 6% of the neurones studied in the hand area of the post-central gyrus. Thus the prevalence of neurones with elongated and direction-selective receptive fields is low in the primary somatosensory cortex in comparison with the visual cortex. These neurones may, however, serve the sterognostic capcity of the hand by contributing information about stimulus motion, orientation and direction of movement on the skin.  (+info)