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J D Haynes

Publications and source records attributed to J D Haynes.

62 records · Page 4Linked to original sources
PubMed1977

Cuta neous basophil responses in neonatal guinea pigs: active immunization, hapten specific transfer with small amounts of serum, and preferential elicitation with phytohemagglutinin skin testing.

Previous studies have demonstrated a failure to elicit delayed hypersensitivity skin responses in neonatal guinea pigs despite apparent immunologic competence of their lymphocytes and monocytes. The ability of neonatal guinea pigs to manifest cutaneous basophil hypersensitivity (CBH) responses was examined. Neonates were competent to express macroscopic and microscopic aspects of these delayed reactions. Strong cutaneous basophil responses were elicited in newborns (0 to 2 days old) in a hapten-specific manner after intravenous transfer of small amounts of immune serum (0.5 ml) obtained from adult donors. Also, neonatal guinea pigs actively immunized at birth with hapten-carrier conjugates emulsified with incomplete Freund's adjuvant (IFA) and skin tested when 1 week old had 24-hr hapten-specific cutaneous basophil reactions and CBH reactions to the carrier protein as well. Compared with adult CBH reactions, neonatal responses had equal concentrations of basophils, fewer monocuclear cells, less macroscopic erythema, and almost no induration. Hapten-specific CBH reactions also contained significant infiltrates of eosinophils which were more prominent in the ear skin vs flank skin and in neonates vs adults. Immunization with complete Freund's adjuvant (CFA) resulted in a marked difference between adults and neonates; adult PPD reactions were quite indurated and contained many more monoculear cells and few basophils, whereas neonatal PPD reactions were flat, erythematous, nonindurated, and contained relatively few mononuclear cells and more basophils. Thus, neonatal tuberculin reactions elicited by PPD in animals immunized with CFA were examples of CBH. Skin testing nonimmune guinea pigs with phytohemagglutinin (PHA) also revealed marked differences in 24-hr cutaneous reactions between adults and newborns. Adults had indurated and erythematous reactions which contained approximately 20% basophils and 80% mononuclear cells, whereas similar PHA skin tests in newborns elicited small macroscopic reactions, which microscopically showed large infiltrates containing approximately 80% basophils and 20% mononuclear cells. It was concluded that neonatal guinea pigs were not only competent to manifest basophil-containig delayed-type reactions, but that cutaneous basophil responses were preferentially elicited in these animals under a variety of circumstances. These results underline the fact that basophil accumulations are one aspect of delayed skin test responses and that the regulation of the arrival of these cells in neonates is different from that in adult guinea pigs.

Animals↗
PubMed1976

Antibody-mediated basophil accumulations in cutaneous hypersensitivity reactions of guinea pigs.

Cutaneous basophil hypersensitivity (CBH) was studied in guinea pigs by using simplified histologic techniques. Animals immunized with oxazolone or picryl conjugates of keyhole limpet hemocyanin (KLH) emulsified with complete (CFA) or incomplete Freund's adjunvant (IFA) were found to have hapten-specific cutaneous basophil reactions when skin tested at 1 week with oxazolone or picryl chloride contant painting or intradermal injection of oxazolone or picryl-conjugated human serum albumin, respectively. Thus, hapten-specific cutaneous basophil reactions were present in guinea pigs immunized with CFA for classical delayed hypersensitivity, and in animals immunized with IFA for Jones-Mote reactions. Hapten-specific 24-hr cutaneous basophil reactions were passively transferred with immune serum from donors sensitized with conjugates of oxazolone or picryl-KLH in CFA or IFA, and with serum from oxazolone contact-sensitized animals as well. As little as 0.5 ml sera obtained from donors 1 week after immunization could systemically transfer cutaneous basophil reactions. It is likely that hapten-specific cutaneous basophil reactions are mediated by small quantities of serum antibodies. We conclude that antibody-mediated cutaneous basophil reactions may be distinctive hypersensitivity responses that can be distinguished from classical anaphylactic, Arthus, and delayed hypersensitivities. It is suggested that CBH reactions are heterogeneous and that antibody products of B lymphocytes, and factors probably derived from T lymphocytes, play a role in basophil accumulations at cutaneous hypersensitivity reactions.

Animals↗
PubMedDate not supplied

Extracting the dynamics of perceptual switching from 'noisy' behaviour: an application of hidden Markov modelling to pecking data from pigeons.

When studying animal perception, one normally has the chance of localizing perceptual events in time, that is via behavioural responses time-locked to the stimuli. With multistable stimuli, however, perceptual changes occur despite stationary stimulation. Here, the challenge is to infer these not directly observable perceptual states indirectly from the behavioural data. This estimation is complicated by the fact that an animal's performance is contaminated by errors. We propose a two-step approach to overcome this difficulty: First, one sets up a generative, stochastic model of the behavioural time series based on the relevant parameters, including the probability of errors. Second, one performs a model-based maximum-likelihood estimation on the data in order to extract the non-observable perceptual state transitions. We illustrate this methodology for data from experiments on perception of bistable apparent motion in pigeons. The observed behavioural time series is analysed and explained by a combination of a Markovian perceptual dynamics with a renewal process that governs the motor response. We propose a hidden Markov model in which non-observable states represent both the perceptual states and the states of the renewal process of the motor dynamics, while the observable states account for overt pecking performance. Showing that this constitutes an appropriate phenomenological model of the time series of observable pecking events, we use it subsequently to obtain an estimate of the internal (and thus covert) perceptual reversals. These may directly correspond to changes in the activity of mutually inhibitory populations of motion selective neurones tuned to orthogonal directions.

Animals↗