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Biomedical subjects

L A Hart

Publications and source records attributed to L A Hart.

At least 37 records · Page 2Linked to original sources
PubMed1996

Companion animals and the psychological health of Alzheimer patients' caregivers.

A sample of 244 persons in northern California who provided care for individuals with possible or probable Alzheimer's disease was studied to examine the effect of association with companion animals on three indices of psychological health. 124 caregivers had regular contact with pets; 120 caregivers did not. Men who were attached to dogs scored better on some measures of psychological health than did men who had no pets. Women less than 40 years old who were attached to cats scored better on some measures of psychological health than did the same-age women who had no pets. Women aged 40 to 59 years who were attached to dogs scored worse on measures of life satisfaction and depression than did the same-age women who had no pets. The data suggested a positive indirect effect on caregivers' mental health through interaction between the pet and the patient, but small strata numbers precluded definitive conclusions. Association with pets appeared to temper some of the psychological stress associated with caring for a cognitively impaired adult among young female and male caregivers but not among middle-aged female caregivers.

Adaptation, Psychological↗
PubMed1995

Association with companion animals and the expression of noncognitive symptoms in Alzheimer's patients.

Interactions with companion animals have been shown to have socializing and calming effects for Alzheimer's patients in an institutional setting. Sixty-four Alzheimer's patients living in the private home were studied, through medical records and information provided by caregivers, to determine what effect association with a companion animal had on the progression of cognitive decline and the manifestation of concomitant noncognitive symptoms. Prevalence of episodes of verbal aggression and anxiety was reported less frequently in 34 patients who were exposed to companion animals compared with patients who were not exposed. Significantly fewer mood disorders were reported in patients who were attached to their pets compared with patients who were not attached. There was no significant difference in the rate of cognitive decline between pet-exposed and nonexposed patients as measured by three standard indices. This study lends preliminary support to the belief that interaction with pets can aid in tempering feelings of agitation and aggression in Alzheimer's patients.

Age of Onset↗
PubMed1995

Dilemmas associated with rehousing homeless people who have companion animals.

66 individuals were given a questionnaire during the initial visit to a veterinary clinic for homeless pet owners. Among the 35 men and 31 women, 32 had been homeless for 6 mo. or less and were termed the acutely homeless subgroup, and 34 had been homeless multiple times or for more than 6 mo. and were termed the chronically homeless subgroup. In responding to the Lexington Attachment to Pets Scale, both men and women participants had significantly higher mean scores on attachment to their pets than did the scale's standardization population. Participants did not differ from the normative sample of adults on the Beck Hopelessness Scale. Both men and women participants stated a preference for being rehoused. 93% of men and 96% of women said that housing would not be acceptable if pets were not allowed. 61% of the men and 33% of the women stated they would be willing to live anywhere pets were allowed except in a shelter. Reluctance to live in a shelter was significantly greater among chronically homeless men than other subgroups, and they also had low desire to be rehoused. A majority of the participants had been refused housing because they had pets. Attempts to rehouse homeless individuals who have pets are likely to be unsuccessful unless accommodation for pets is included.

Adult↗
PubMed1995

The pleasures and problems of hearing dog ownership.

Emotional aspects of owning hearing dogs were explored in 38 hearing-dog owners and a control group of 23 prospective owners. Both groups listed companionship and hearing assistance as pleasant reasons for owning such dogs. Having a dog and personal independence were reasons mentioned only by prospective owners. Both groups mentioned travel complications as unpleasant problems. Owners referred to dogs' behavior problems significantly more often than did prospective owners who appeared to have unrealistic expectations that dog ownership would be problem-free.

Activities of Daily Living↗
PubMed1993

The role of pet dogs in casual conversations of elderly adults.

Casual conversations were recorded as elderly persons routinely walked their dogs through a familiar mobile home park in the United States. Control observations included walks without dogs by owners and non-owners of dogs. All owners talked to and about their dogs. Transcribed conversations indicated that dogs were a primary focus of conversation. A majority of sentences to dogs were imperatives; the owners were instructing the dogs. Dog owners frequently included dogs' names or nicknames in their sentences when they spoke to the dogs and made reference to the dogs' wishes or needs. Speaking to dogs was also associated with frequent repetition of sentences. Passersby talked to the owners about their dogs whether or not the dogs were present. When dog owners spoke with other people, their conversations often concerned activities that were occurring in the present, whereas conversations of non-owners focused on stories about past events. Dog owners reported taking twice as many daily walks as non-owners. Dog owners also reported significantly less dissatisfaction with their social, physical and emotional states.

Aged↗
PubMed1993

The anti-arthritic and immunosuppressive effects of cyclosporin A on collagen-induced arthritis in the rhesus monkey.

The influence of cyclosporin A (CsA) on type II collagen-induced arthritis (CIA) in the rhesus monkey has been investigated. CsA was administered subcutaneously in a dose of 25 mg/kg per day during 9-18 days and additionally 12.5 mg/kg per day for 7 days. At this dosing regime no significant alterations of haematologic parameters were found, indicating that the toxicity of CsA was negligible. Administration of CsA after onset of arthritis had no beneficial effect, but when given between immunization and manifestation of clinical symptoms, CIA could be prevented completely. Moreover, these monkeys became resistant to the disease, because no arthritic activity could be observed upon a booster immunization with type II collagen (CII). The suppression of disease by CsA is reflected in reduced antibody levels to CII.

Animals↗
PubMed1989

Immunodulatory compounds from Picrorhiza kurroa: isolation and characterization of two anti-complementary polymeric fractions from an aqueous root extract.

Two aqueous root extracts of Picrorhiza kurroa, one prepared by extraction at 4 degrees C and the other by refluxing, were purified using the guidance of modulation of classical (CP) and alternative (AP) pathway complement activity. By means of methanol extraction and gel filtration chromatography, two polymeric fractions were isolated from the cold water extract. A methanol-soluble polymeric fraction (CS1) was highly active in inhibiting CP complement activity exclusively, whereas a methanol-insoluble polymeric fraction (CI1) exhibited an inhibitory effect on both CP and AP complement activity. Preliminary chemical analysis of the anti-complementary fractions revealed the presence of structures of carbohydrate and of peptide nature in CS1 and CI1. The modulation of CP complement activity by CS1 was studied in more detail. Its inhibitory effect was proven to be based on complement consumption rather than on chelation of Ca2+ and/or Mg2+ or on stabilization of the target cells in the complement-assay. The purification of the aqueous extract prepared by refluxing, resulted in the isolation of a polymeric fraction with the same qualities as CS1. However, a fraction with properties similar to CI1 could not be isolated from this extract.

Adjuvants, Immunologic↗
PubMed1989

Characterization of anti-complement compounds from Azadirachta indica.

The crude aqueous extract of Azadirachta indica bark possesses an inhibitory activity on both classical (CP) and alternative pathway (AP) activation of human complement. Purification of the compounds with the guidance of the AP-inhibitory activity involved extraction with methanol, dialysis, ion-exchange procedures and gel-permeation chromatography. This sequence yielded two polymers, NB-I and NB-II, one a highly active compound with a relatively low molecular weight (NB-II) and the other a less active compound with a high molecular weight (NB-I). The polymers were characterized by using colour reactions, TLC, GLC and HPLC after hydrolysis and gel-permeation chromatography as peptidoglycans. The carbohydrate part consisted predominantly of glucose. Arabinose, galactose and mannose were present in minor amounts (NB-II) or only as traces (NB-I). Protein was present for 5.5% in NB-I and for 9.8% in NB-II.

Chemical Phenomena↗
PubMed1989

Inhibitory activity of Jatropha multifida latex on classical complement pathway activity in human serum mediated by a calcium-binding proanthocyanidin.

This study isolates and characterizes the anti-complement constituent(s) present in the latex of Jatropha multifida, in an attempt to explain the traditional application of the latex in the treatment of infected wounds. Guided by the inhibition of classical pathway (CP) complement activity in human serum, a polymer was isolated which could be characterized as a proanthocyanidin. The polymer inhibits CP activation of the complement cascade, while alternative pathway (AP) activation is relatively insensitive to the polymer. This is due to the selective depletion of Ca2+, but not Mg2+, from the incubation medium.

Anthocyanins↗
PubMed1989

Social acknowledegments for children with disabilities: effects of service dogs.

While service dogs are known to perform important tasks for people using wheelchairs, such as retrieving dropped items or pulling a wheelchair, they may also serve as an antidote for social ostracism. Adults in wheelchairs have been found to receive many more social acknowledgements when a service dog is present than when not. This study examined whether disabled children in wheelchairs with service dogs receive more frequent social acknowledgment than when no dog is present. Behaviors of passersby in response to children in wheelchairs were recorded in shopping malls and on school playgrounds. In both settings, social acknowledegments (e.g., friendly glances, smiles, and conversations) were substantially more frequent when a service dog was present. Social effects of the dog were more pronounced in shopping malls, typical of unfamiliar settings where the child would be likely to experience being ignored or overlooked. Service dogs may assist in normalizing the social interactions for children with disabilities producing social isolation.

Adolescent↗
PubMed1988

Alteration in vomeronasal system anatomy in alcelaphine antelopes: correlation with alteration in chemosensory investigation.

Ruminants typically have an incisive papilla and incisive ducts located on the hard palate just behind the dental pad which are involved in transferring fluid-borne stimulus material from the oral cavity to the vomeronasal organs (VNOs) during flehmen. This behavior in males is presumably involved in the detection of chemosensory cues in female urine which indicate sexual status. Two species of alcelaphine antelopes, topi and Coke's hartebeest, were found to lack the incisive papilla and incisive ducts constituting the oral connection to the VNOs. This distinctive anatomical feature is complemented in these species not only by lack of flehmen behavior, but also a de-emphasis on chemosensory interest in female urine during sexual encounters. The common wildebeest, which is also an alcelaphine antelope, lacks the incisive papilla, but has small incisive ducts. Wildebeest males do perform flehmen to urine from females. However, during flehmen in the wildebeest, intermittent nostril licking apparently delivers the stimulus material to the VNOs via the nasal route, possibly compensating for reduced oral access to the VNOs. These observations on alcelaphine antelopes would appear to represent a unique feature among the world's ruminants.

Animals↗
PubMed1988

Evidence that superoxide-anion, produced by PMA-activated human polymorphonuclear leukocytes, is the cytolytic agent for rabbit, but not for sheep red blood cells.

The lysis of sheep and rabbit red blood cells (SRBC and RRBC, respectively) upon exposure to PMA-activated human polymorphonuclear leukocytes (PMN) was investigated. The lysis of these target cells, which was measured by the release of 51Cr, showed different kinetics and scavenger-sensitivity. The lysis of RRBC, which was already detectable within 45 min of incubation, was sensitive to superoxide dismutase (SOD), but was only poorly influenced by scavengers of hydroxyl radical formation, such as desferal or thiourea. In contrast, lysis of SRBC was first detectable after 90 to 135 min of incubation and sensitive to desferal and thiourea, but not to SOD. Finally, only RRBC were sensitive to the artificial superoxide-generating system hypoxanthine/xanthine oxidase. Taken together, these data point at a cytolytic activity of superoxide anion O2- towards RRBC. SRBC are relatively resistant to O2-, but are lysed by an H2O2- and hydroxyl radical-dependent process.

Animals↗
PubMed1988

The effects of service dogs on social acknowledgments of people in wheelchairs.

Able-bodied people often exhibit behaviors that show them to be socially uncomfortable upon encountering a physically disabled stranger. These behaviors include less eye contact, gaze avoidance, greater personal distance, and briefer social interactions. This study examined whether persons in wheelchairs with service dogs receive more frequent social acknowledgement from able-bodied strangers than people in wheelchairs without dogs receive. Behaviors of passersby were recorded by an observer who followed a person in a wheelchair at a distance of 15 to 30 feet. Observations were made in public areas amid pedestrian traffic, areas such as shopping malls and a college campus. The behaviors of passersby to the person in a wheelchair, with or without a service dog, were recorded, including smiles, conversation, touch, gaze aversion, path avoidance, or no response. Results indicated that both smiles and conversations from passersby increased significantly when the dogs were present. These findings suggest that the benefits of service dogs for their owners extend beyond working tasks to include enhanced opportunities for social exchange. The service dogs substantially reduced the tendency of able-bodied people to ignore or avoid the disabled person.

Adult↗