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Biomedical subjects

G Richmond

Publications and source records attributed to G Richmond.

At least 19 recordsLinked to original sources
PubMed2001

Structure and bonding of molecules at aqueous surfaces.

Significant advances toward understanding the structure of aqueous surfaces on a molecular level have been made in recent years. This review focuses on the recent contributions of surface vibrational sum frequency spectroscopy (VSFS) to this field of study. An overview of recent VSFS studies of the molecular structure and orientation of molecules at the vapor-water interface and the interface between water and an immiscible organic liquid is presented, with particular emphasis on studies that compare the molecular properties and adsorbate behavior at these two different but related interfaces. This discussion is preceded by a general introduction to VSFS studies at aqueous surfaces and a description of the fundamental principles underlying the technique.

Journal Article↗
PubMed1994

Alterations in the PITSLRE protein kinase gene complex on chromosome 1p36 in childhood neuroblastoma.

p58cdc2L1, a protein kinase implicated in apoptotic signaling, is one of eight separate kinases encoded by three tandemly duplicated and linked genes, which we have termed PITSLRE A, B and C. One allele of this complex on chromosome 1 was either deleted or translocated in each of 18 neuroblastoma cell lines with cytogenetically apparent 1p alterations. A protein encoded by this locus, PITSLRE gamma 1, was absent in three of the lines and a smaller, apparently truncated, PITSLRE polypeptide was found in another line. These findings identify a novel gene complex on chromosome 1 that encodes a protein kinase subfamily. We suggest that the PITSLRE locus may harbour one or more tumour suppressor genes affected by chromosome 1p36 modifications in neuroblastoma.

Alleles↗
PubMed1994

Plasma clozapine concentrations predict clinical response in treatment-resistant schizophrenia.

Steady-state blood clozapine concentrations in 58 schizophrenic patients varied more than 45-fold (40-1911 ng/mL) after fixed-dose treatment (400 mg/day). Discriminant function analysis determined that a blood clozapine concentration of 420 ng/mL optimally distinguished responders from nonresponders. After 4 weeks of treatment, only 8% of those patients with a blood clozapine concentration < 420 ng/mL responded compared with 60% of those who had a blood clozapine concentration > 420 ng/mL. When plasma concentrations were increased above 420 ng/mL (by a double-blind random assignment procedure), nonresponders increased their response rate to 73% if their plasma concentrations at Week 12 exceeded 420 ng/mL compared with a response rate of 29% if their Week 12 levels remained below 420 ng/mL (chi 2 = 4.2, p < .04).

Adult↗
PubMed1992

Primary pulmonary hypertension and human immunodeficiency virus infection in a non-hemophiliac man.

We describe clinical and postmortem findings in a 44-year-old man with pulmonary hypertension and infection with the human immunodeficiency virus (HIV-1). Plexogenic angiopathy and veno-occlusive lesions were present, in addition to a mild, patchy pulmonary interstitial lymphoid infiltrate. The clinical data for 14 previously reported cases of HIV-associated primary pulmonary hypertension are summarized. We speculate that these vascular changes may be due to damage from a specific immune response to HIV.

Adult↗
PubMed1990

Tobacco advertising in gender-oriented popular magazines.

The number and content of tobacco advertisements were examined in seventy-four gender-oriented popular magazines published during the summer of 1988. More ads were present in women's than men's magazines, and the messages contained in these ads were differentially stressed as a function of the magazine's primary readership. The type of Surgeon General's warning appearing in an ad often was not directed toward the typical concerns of the readership of the magazine in which the ad appeared. This survey, and a follow-up three months later, indicated that the Surgeon General's report on nicotine addiction, published in the Spring of 1988, had no apparent effect on the number of ads placed. Advertising revenues received by publishers from conglomerates which control the manufacture of food as well as tobacco products may be partially responsible for this finding. It was concluded that effective drug education programs should encourage skepticism when tobacco advertisements are examined.

Adult↗
PubMed1988

Ventromedial hypothalamic lesions and cholinergic control of female sexual behavior.

Ovariectomized female rats received bilateral electrolytic or sham lesions of the ventromedial nucleus of the hypothalamus (VMNH). They were tested for sexual receptivity in response to estrogen (EB) and progesterone (P) treatment. Following this they were treated with a small dose of EB and tested for their response to intraventricular microinjection of a muscarinic cholinergic agonist or a vehicle solution. Those animals with lesions involving almost the entire extent of the VMNH displayed an impaired response to EB and P and to the agonist. Lesions which spared 30-50% of the anterior portion of the VMNH did not result in an impairment to EB and P or to the agonist. It is suggested that the disruption of the cholinergic induction of receptivity by such lesions was due either to destruction of estrogen receptors located in cell bodies in the VMNH which send projections to extrahypothalamic cholinergic neurons or to estrogen- and cholinergic-responsive cells intrinsic to the VMNH which are critical for the expression of sexual receptivity.

Animals↗
PubMed1987

The aberrant behavior checklist: factor structure and the effect of subject variables in American and New Zealand facilities.

The Aberrant Behavior Checklist was used to collect data from a large United States institution for comparison with ratings previously obtained in New Zealand. A total of 531 subjects within the American facility and 937 residents of New Zealand institutions were studied. The United States data were factor analyzed using the same procedures that were employed to develop the scale in New Zealand. In addition, subscales of the Checklist were analyzed as a function of sex, age, country, and level of mental retardation. Finally, the effects of various medical conditions were analyzed. The original factor structure of the Checklist was validated for the United States sample, with a mean coefficient of congruence of .93 averaged across the five factors. Sex failed to influence subscale scores, whereas age, country, and severity of retardation significantly affected ratings. Deafness was unrelated to Checklist scores whereas cerebral palsy, epilepsy, psychosis, and psychoactive drug treatment were related.

Adult↗
PubMed1986

Cholinergic mediation of feminine sexual receptivity: demonstration of progesterone independence using a progestin receptor antagonist.

Feminine sexual receptivity can be elicited by the intracerebral administration of muscarinic cholinergic substances in ovariectomized female rats treated with small amounts of estrogen. These experiments were designed to investigate whether this facilitative cholinergic mechanism is dependent upon progesterone. In the first experiment, estrogen-primed animals were injected with RU 38486, a progestin receptor antagonist, 1 h before progesterone or vehicle injection. Injection of RU and progesterone on Day 1 of testing produced animals which were sexually unreceptive. Furthermore, injection of the antagonist without concomitant progesterone produced animals which were unresponsive to progesterone given 24 h later. Thus, RU 38486 itself may be binding to progestin receptors in critical brain regions, preventing progesterone from binding to these same receptors. In Experiment 2, animals made sexually unreceptive by treatment with RU 38486 subsequently became receptive when injected intracerebrally with oxotremorine, a muscarinic agonist. Therefore, activation of progestin receptors does not appear necessary for the cholinergic mediation of sexual receptivity. As in Experiment 1, animals receiving progesterone on Day 1 showed a diminished response to a second progesterone injection 24 h later; an even greater decrease in this response was observed in animals that also received the antagonist on Day 1.

Animals↗
PubMed1986

Evidence for involvement of midbrain central gray in cholinergic mediation of female sexual receptivity in rats.

Experiments were designed to determine the role of the midbrain central gray (MCG) in facilitation of lordosis by cholinergic agonists. In Experiment 1, estradiol-treated female rats received microinjections of carbachol into the MCG and showed a dose-related behavioral facilitation to the agonist. In Experiment 2, MCG injections of oxotremorine (OXO), a selective muscarinic receptor agonist, yielded a dose-related facilitation; this was blocked by systemic pretreatment with scopolamine (SCOP), a muscarinic antagonist. In Experiment 3, MCG-lesion animals were injected unilaterally with OXO intraventricularly following contralateral injection of SCOP or vehicle. Females with MCG damage displayed significantly less facilitation than sham-lesion animals. Pretreatment with SCOP abolished lordosis facilitation in both groups. In addition, after treatment with estradiol and progesterone, sham-lesion females showed more receptivity than MCG-lesion females. Systemic injection of SCOP produced a significant decline in lordosis for both groups. On the basis of these data, it is suggested that the MCG plays an important role in the cholinergic mediation of female sexual receptivity.

Animals↗
PubMed1985

Computers working for medicine.

A demonstration of the use of Viewdata Systems in clinical trials is presented. The potential of these systems in several areas of medicine is shown and related to their speed of development in the last 2 years. Particular reference is made to the use of computers in the assessment of patients with affective disorders.

Computers↗
PubMed1984

Maternal discrimination of pup sex in rats.

In recent studies (Moore, 1981, 1982; Moore & Morelli, 1979), it has been found that maternal female rats spend more time licking the anogenital region of male than female offspring. This discrimination of pup sex has important implications for the development of a number of sex differences in behavior later in life, and the present study was designed to re-examine Moore's observations while allowing each pup to be individually identified. Litters of Sprague-Dawley rats were delivered by Caesarean section, and the footpads of each animal were tattooed with India ink to permit identification throughout testing. Each litter was then fostered to a maternal female and remained with her except when observations of maternal licking were made--on the fourth, seventh, and tenth days after delivery. On each of these days, the foster mother was placed in a test chamber for 30 min, and each pup was then presented individually for a 10-min session. During this time the number and duration of anogenital licking episodes were recorded. We found, as did Moore, that adult females do distinguish between their male and female pups, spending significantly more time licking the anogenital region of the males in their litters on all but the first day of testing. The possibility that the attentional bias toward male young has important consequences for behavior later in life and contributes to behavioral differences between the sexes (Beach, 1979; Moore, 1982) makes the identification of individual animals throughout development important in the analysis of these effects.

Animals↗
PubMed1984

Further evidence for masculinization of female rats by males located caudally in utero.

The morphology and behavior of female rodents is partially masculinized as a result of residence near males in the same uterine horn (Clemens effect). Two hypothetical mechanisms have been proposed to account for this effect. In the first hypothesis ("contiguity") androgens secreted by males in utero are proposed to diffuse across the amniotic membrane, reaching adjacent fetuses. In the second hypothesis ("caudal male") androgens are transported via the cervical-to-ovarian blood flow and may diffuse directly between closely apposed uterine veins and arteries. This study was designed to test directly which of these mechanisms appears more influential in masculinizing the morphology of female rats. Pregnant Sprague-Dawley rats were decapitated early on Day 22 of gestation and pups were Caesarean delivered. Their anogenital distance and body weight were recorded, location in utero coded by means of footpad tatooing, and each litter fostered to a maternal female. Measurements were taken again when the animals were weaned. Statistical analysis revealed that the presence of one or more males caudal to a female in the uterine horn has a more critical influence on that female's morphology than contiguity per se. Such a mechanism may result in partial masculinization of dimorphic behaviors later in life.

Androgens↗
PubMed1984

Improving profoundly mentally retarded adults' performance on a position discrimination.

The relative importance of stimulus manipulations antecedent to or consequent on the response was investigated in three experiments related to position discrimination. In the first experiment, two different stimuli (either a piece of candy or a toy cat) were hidden under one of three boxes in full view of 2 profoundly mentally retarded adults. The behavior of uncovering the hidden object was measured using a combined multiple baseline and reversal design. In Experiment II, an entire unit of profoundly retarded adults was screened to determine the prevalence of the effects observed in Experiment I. In Experiment III, an attempt was made to determine whether the difference in antecedents (candy vs. kitty) or consequences accounted for the superior performance when the candy was hidden. In this experiment, using a reversal design with four profoundly retarded adults, we found that the antecedent manipulation (hiding the candy vs. hiding the toy cat) resulted in better performance than did the manipulation of the consequence (handing subjects the candy or allowing them to uncover and consume it).

Adolescent↗
PubMed1984

Survey of bruxism in an institutionalized mentally retarded population.

Bruxism was assessed in a population of 358 institutionalized mentally retarded individuals using two independent indexes: toothwear and staff reports. Bruxism based upon toothwear was found in 58%. Bruxism identified by staff reports was found in 41% of the population. No sex differences were observed. Three bruxer subgroups were identified: daytime only (17%), night only (8%), and day and night (16%). Older residents were more likely to grind their teeth than were younger residents. These results, when compared with other reports, suggest that bruxism is more likely to occur in the institutionalized mentally retarded population than in the nonretarded population.

Adolescent↗
PubMed1983

Shaping bladder and bowel continence in developmentally retarded preschool children.

A program to improve bladder and bowel continence was evaluated in a preschool with four developmentally retarded children. During baseline, the children were taken to the toilet on a regular schedule, once an hour. The training program increased this frequency to once every 15 minutes for the 1st week, every 30 minutes the 2nd week, every hour the 3rd week, and every 2 hours in the 4th week. Using the toilet appropriately was reinforced with social praise and liquids. Accidents resulted in a brief verbal reprimand and simple correction (i.e., going to the bathroom, changing clothes, and sitting on the toilet). All four children showed improvement in their bladder and bowel continence. Results of the program are discussed in terms of improved efficiency of toilet training programs and their use with developmentally retarded preschool children.

Behavior Therapy↗