The facilitation of social interactions by domestic dogs

Abstract

Research suggests that dogs can facilitate social interactions, which, in turn, may promote psychological health. This study explored the ability of dogs to facilitate social responses relative to other accompaniments and investigated whether the social catalysis effect is generic or influenced by the appearance of the dog. The behavior of 1800 pedestrians approaching a female experimenter was recorded as a function of the presence of three dogs (Labrador Retriever pup, Labrador adult, Rottweiler adult) and two neutral stimuli (teddy bear, potted plant). The behavior of pedestrians approaching the woman whenever she was alone (control) was also explored. Information was collected on the passers-by’ gender, number of people in the party, type of acknowledgement elicited and length of conversations. More people ignored the experimenter whenever she was alone or with the teddy or plant, than whenever she was walking a dog. The Rottweiler resulted in more nonresponses than the puppy or adult Labrador, who in turn elicited more smiles and verbal responses. Females, and those alone, elicited more smiles and conversations than males, or those in pairs. It is concluded that dogs can facilitate social interactions between adults better than other accompaniments; however, the social catalysis effect is not generic, but dog specific.     

Respiratory response to partial paralysis in anesthetized dogs

The ability to maintain alveolar ventilation is compromised by respiratory muscle weakness. To examine the independent role of reflexly mediated neural mechanisms to decreases in the strength of contraction of respiratory muscles, we studied the effects of partial paralysis on the level and pattern of phrenic motor activity in 22 anesthetized spontaneously breathing dogs. Graded weakness induced with succinylcholine decreased tidal volume and prolonged both inspiratory and expiratory time causing hypoventilation and hypercapnia. Phrenic peak activity as well as the rate of rise of the integrated phrenic neurogram increased. However, when studied under isocapnic conditions, increases in the severity of paralysis, as assessed from the ratio of peak diaphragm electromyogram to peak phrenic activity, produced progressive increases in inspiratory time and phrenic peak activity but did not affect its rate of rise. After vagotomy, partial paralysis induced in 11 dogs with succinylcholine also prolonged the inspiratory burst of phrenic activity, indicating that vagal reflexes were not solely responsible for the alterations in respiratory timing. Muscle paresis was also induced with gallamine or dantrolene, causing similar responses of phrenic activity and respiratory timing. Thus, at constant levels of arterial CO2 in anesthetized dogs, respiratory muscle partial paralysis results in a decrease in breathing rate without changing the rate of rise of respiratory motor activity. This is not dependent solely on vagally mediated reflexes and occurs regardless of the pharmacological agent used. These observations in the anesthetized state are qualitatively different from the response to respiratory muscle paralysis or weakness observed in awake subjects.(ABSTRACT TRUNCATED AT 250 WORDS)     

Attempt to isolate from Ascaris suum an antigenic fraction for use in the immunologic diagnosis of onchocerciasis

For the purpose of immunological diagnosis of onchocerciasis, the authors attempted to isolate an antigenic fraction from Ascaris suum which would only detect anti-Onchocerca volvulus antibodies. Chromatofocusing was done on a crude antigenic preparation from the ascaris. Immunoelectrophoresis showed that the fraction eluted between pH 5.6 and pH 4.9 contained antigens which reveal anti-Onchocerca antibodies; anti-Loa loa antibodies are revealed by the fraction eluted at pH less than 4. From the fraction which reveal anti-Onchocerca antibodies, affinity chromatography isolated a system in which three components were detected by electrofocusing at a Pi of about pH 5.5. The specificity and sensitivity of this system are being studied.     

Enkephalin-induced changes in ventilation and ventilatory pattern in adult dogs

We studied the changes in ventilation induced by intracisternal administration of enkephalins in four unanesthetized adult dogs. Instantaneous minute ventilation (VT/TT) decreased markedly after D-Ala-Met-enkephalinamide (DAME). Mean VT/TT decreased maximally by 20-50 min after DAME and lasted an additional 15-60 min; by 2 h, VT/TT had returned to base line. Four doses (5, 25, 60, and 125 micrograms/kg) of DAME were used, and the ventilatory response depended on the dose. Mean inspiratory time decreased but mean expiratory time and mean TT showed a marked prolongation. Periodic breathing (2-3 breaths separated by long apneic pauses) occurred in every study and the frequency of sighs increased considerably. All these ventilatory changes were reversed by low doses of naloxone or naltrexone; in addition, VT/TT increased well above base line after the administration of these antagonists. However, naloxone did not increase VT/TT when injected without prior administration of DAME. We conclude that 1) the decrease in VT/TT is due to a decrease in respiratory duty cycle; 2) periodic breathing and increased frequency of sighs constitute part of the changes in the ventilatory pattern induced by DAME; 3) a ventilatory withdrawal reaction may occur after a receptor-agonist interaction of short duration; and 4) although enkephalins can modulate ventilation and the breathing pattern in a major way, these data provide no evidence suggesting that this modulation is tonic.     

An Attempt at Phage Typing in the Genus Serratia

S ummary : The present report gives the results of the effect of 10 bacteriophages of Serratia marcescens on 107 strains of the genus Serratia . The phage S103 was the most effective (80% strains lyzed), and the phage PK the least (12% strains lyzed). Only 13 strains were resistant to all the phages studied. The majority of the strains of the genus studied could be allocated to one of seven groups on the basis of their sensitivity to the phages.