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Biomedical subjects

C Mason

Publications and source records attributed to C Mason.

At least 55 records · Page 3Linked to original sources

Requirement of Ras-GTP-Raf complexes for activation of Raf-1 by protein kinase C.

Receptor tyrosine kinase-mediated activation of the Raf-1 protein kinase is coupled to the small guanosine triphosphate (GTP)-binding protein Ras. By contrast, protein kinase C (PKC)-mediated activation of Raf-1 is thought to be Ras independent. Nevertheless, stimulation of PKC in COS cells led to activation of Ras and formation of Ras-Raf-1 complexes containing active Raf-1. Raf-1 mutations that prevent its association with Ras blocked activation of Raf-1 by PKC. However, the activation of Raf-1 by PKC was not blocked by dominant negative Ras, indicating that PKC activates Ras by a mechanism distinct from that initiated by activation of receptor tyrosine kinases.

Animals↗

Consensual partnering in Australia: a review and 1991 census profile.

"This paper is the first part of a two-part examination of consensual partnering in Australia. It reviews the Australian literature on consensual partnering, summarizing evidence of its proliferation since the mid-1960s and also the findings of investigations into its nature and the personal attributes that predispose some people more than others to adopt it. It then discusses the shortcomings of Australian census data as a source for studying consensual unions, before using data from the 1991 Census to present the first elements in a comprehensive profile of the cohabiting population. These cover the basic demography of consensual partnering: the ages, marital statuses and family type distributions of those involved."

Age Distribution↗

Emergency treatment of orodental injuries: a review.

There has been an increase in the incidence of injuries to the incisor teeth in the primary and permanent dentitions over the last decade; one study reported that roughly 35% of 9-year-old children will have damaged their teeth in some way. Much has been written about dental injuries, and there may be confusion about the appropriate emergency treatment for different types. Classification and understanding of the types of injury are essential before diagnosis and treatment can be undertaken. Although dental injuries can occur singly, they more usually involve a combination of injuries to a tooth and its supporting structures. Prompt, accurate diagnosis and appropriate emergency treatment as outlined in this paper will greatly improve the prognosis for many dentoalveolar injuries. The aim must be to ensure that the third of the population of preteenage children who damage their teeth are not resigned to loss of an incisor in later life because of inaccurate diagnosis and poor treatment of the emergency condition.

Child↗

Group psychotherapy for women molested in childhood: psychological and somatic symptoms and medical visits.

Molested women who completed a series of 16 weekly group psychotherapy sessions conducted by social workers improved substantially regarding various aspects of psychological functioning, including self-image, coping techniques, relationship issues, and mothering. In addition, there was significant improvement in all psychological symptom scales and all global indices of symptomatic distress measured by the SCL-90-R. Furthermore, the improvement was present immediately after therapy and, with the exception of the hostility score, persisted 1 year later. Although the somatization score was reduced, the number of visits for physical symptoms did not change. The patients studied manifested characteristics typical of previously surveyed women with a history of childhood abuse, including a frequent history of major surgery (Drossman et al., 1996; Longstreth & Wolde-Tsadik, 1993; Springs & Friedrich, 1992) and, in some, a previous problem with alcohol (Springs & Friedrich, 1992; Walker et al., 1995) or drugs (Longstreth & Wolde-Tsadik, 1993; Miller & McCluskey-Fawcett, 1993; Springs & Friedrich, 1992). Also, nearly one half of the subjects had irritable bowel syndrome, the prototypical functional bowel disorder (Drossman et al., 1995; Longstreth & Wolde-Tsadik, 1993; Scarinci et al., 1994; Walker et al., 1995). Most of their baseline SCL-90-R scores were > 1 SD above the nonpatient norms. A problem inherent in assessing the long-term benefit of this study and other group psychotherapy studies is the tendency for some patients to continue similar or different forms of therapy after completing the group sessions. More than one half of patients received subsequent therapy that could have influenced their status at 1-year follow-up. However, most of the symptom dimensions and all global indices were similar 1 year posttherapy in the women who did not receive more treatment as compared to results in the women who did. Patients who received additional therapy had higher somatization scores before, immediately after, and 1 year posttherapy; scores in the other group increased 1 year posttherapy. Although the indications for subsequent therapy were not surveyed, there was an association between additional psychological care seeking and somatization. Furthermore, improvement in psychological status reflected by the phobic-anxiety score immediately posttherapy may have contributed to the decision of some patients to seek subsequent therapy. In the group without additional treatment, the loss of some of the initial somatization improvement at 1 year may have contributed to the lack of reduction in medical care visits in the combined groups. We speculate that provision of additional therapy to more patients might have had a long-term effect on somatization and reduced medical visits. We obtained complete psychological data and nearly complete medical-visit data on our patients, and our survey included 1-year follow-up. Our survey did not meet rigorous methodological standards for an outcome study, however. We surveyed only a small number of patients and did not collect similar data on an untreated control group. It was not possible to distinguish health care visits for organic versus functional disorders, but such a distinction may be artificial, because psychological factors may influence health care seeking for "organic" illness. Because our measurements came from a subset of our patients who were willing to complete the survey questionnaires, we do not know how generalizable the findings are. There is increasing awareness among health care professionals that childhood sexual abuse is common and that it may have serious and long-term psychological and medical sequelae. Our data suggest that group psychotherapy by social workers for women victims may have long-lasting psychological and somatic symptom benefits. Reduction in health care usage was not found, and this outcome may require the identification and treatment of patients who need additi

Adult↗

Platelet serotonin measures in adolescents with conduct disorder.

Dysregulation of serotonergic function has been associated with aggression in several studies involving children, adolescents, and adults. This study investigated the relationship of platelet serotonergic measures to conduct disorder type, severity of aggression, and social skills impairment. Standardized assessments of diagnosis, aggression, impulsivity, and social skills were obtained from 43 male adolescents (ages 13-17) incarcerated at an involuntary residential treatment facility for juvenile offenders. Blood samples were collected and assayed for whole blood serotonin (5-HT) and platelet [3H]-paroxetine-labeled 5-HT-transporter binding. Whole blood 5-HT was higher in adolescents with conduct disorder, childhood type than in subjects with conduct disorder, adolescent type. Whole blood 5-HT was positively correlated with violence rating of the current offense and total offense points, and staff ratings of social skills impairment. Our findings are consistent with a relationship between 5-HT dysregulation and aggressive behavior in incarcerated adolescent boys with conduct disorder, particularly of childhood onset.

Adolescent↗

The molecular epidemiology of HIV-1 among male sex workers in northern Thailand.

Male commercial sex workers (CSWs) in northern Thailand are at high risk for HIV-1 infection and may be exposed to multiple subtypes of HIV-1 through sexual contact with men and women from Thailand, other Asian nations, and the West. We studied 103 male Thai nationals working in gay bars and clubs in Chiang Mai city who participated in the 1994 sentinel surveillance of the Thai Ministry of Public Health using HIV serologic testing, DNA polymerase chain reaction methods, molecular cloning, differential colony hybridization, nucleotide sequencing, and a third hypervariable region (V3) peptide enzyme-linked immunoabsorbent assay to differentiate subjects infected with HIV-1 subtypes B, E, both, or neither. The majority (58%) reported heterosexual orientation, and 35 (34%) were married. Seventeen (16.5%) were HIV infected: 16 (94%) of 17 had HIV-1 subtype E; 1 had HIV-1 subtype B. Two subjects had dually reactive results by molecular techniques but colony hybridization sequencing revealed only HIV-1 subtype E. HIV-1 subtype E appears to be the predominant clade among male CSWs in northern Thailand. This may have important implications for the global kinetics of the HIV epidemic.

Acquired Immunodeficiency Syndrome↗

Liquid sterilization versus high level disinfection in the urologic office.

OBJECTIVES: Systems are available for liquid sterilization (LS) and high level disinfection (HLD) of flexible cystoscopes. Guidelines from the Association of Operating Room Nurses and the Association for Professionals in Infection Control and Epidemiology recommend HLD for urologic endoscopic equipment. We examine these methods emphasizing costs, performance of procedure, and maintenance. METHODS: The process of LS using the Steris System 1 Processor (SSP1) was studied from June 1993 to June 1994. The Voluntary Hospital Association (VHA) Plus Glutaraldehyde HLD system was evaluated from July 1994 to July 1995. Costs are those incurred by the Ochsner Department of Urology over these same periods. RESULTS: Purchase of the SSP1 system proved costly: $16,200 for purchase; $8645 for accessories, service contract, and training seminars; and $5800 for unit installation. Two gallons of glutaraldehyde including the disinfection container cost $15.60. Since government regulation requires less than 0.2 ppm airborne glutaraldehyde concentration, some facilities may need to install ventilation systems. There were no clinical differences between the two systems. Yearly operating expenses in our department for SSP1 was $6037 compared to $445 for HLD. Mean length of time to process was 35 minutes per use for SSP1 and 20 minutes for HLD. Repair of seven cystoscopes during the SSP1 period cost $11,500. No repairs were required for the cystoscopes used during the HLD period. CONCLUSIONS: Outpatient flexible cystoscopy was performed an average of 988 times per year during the study period. Major cost savings were incurred with institution of the HLD system and no endoscope repairs were necessary. There were no clinical differences between the two systems.

Costs and Cost Analysis↗

Early management of dental pain in children and adolescents.

OBJECTIVES: There is little information regarding the initial management of dental pain in children and adolescents. The present study investigated the early management of 155 children and adolescents with dental pain prior to definitive treatment in the Eastman Dental Institute and Hospital for Oral Health Care Sciences, London, UK. METHOD: Prior to the child being examined by a qualified dentist in the casualty department, the accompanying parents or guardians were requested to complete a self-administered questionnaire regarding the duration and severity of pain, presence of swelling, professional advice sought and medication taken. RESULTS: Of the attending children, 83% were in pain, 20% having been in pain for over 1 month. Most parents sought professional health care advice, particularly from a dentist; however, 15% initially obtained advice from a medical practitioner and 5% from a pharmacist. Simple analgesics were taken by 74% of patients; however, these rarely produced complete pain relief. Of concern, 10 children were inappropriately given aspirin, three of whom had taken the aspirin on the advice of a pharmacist. Sixty-seven children received systemic antibiotic therapy; however, 31% of these patients did not have any local swelling. CONCLUSION: It is evident that children and adolescents often receive inappropriate initial treatment for dental pain and may thus suffer unnecessary symptoms for several weeks. There is thus a need to educate healthcare workers more appropriately on aspects of the management of oral pain and to promote oral health care and hence reduce the incidence of caries in children.

Adolescent↗

Role of myelin basic protein and proteolipid protein genes in multiple sclerosis: single strand conformation polymorphism analysis of the human sequences.

Susceptibility to multiple sclerosis (MS) is widely held to have a strong genetic component. While the identities of genes conferring susceptibility are currently unknown, possible candidates include those genes coding for proteins which function in central nervous system (CNS) myelin. Two such genes are the human myelin basic protein (MBP) and proteolipid protein (PLP) genes, whose products make up approximately 80% of the total protein in CNS myelin. The association of a variable number tandem repeat (VNTR) 5' to the human MBP gene with MS has been the subject of conflicting reports. Here we test the hypothesis that mutations in the human MBP and PLP genes might be associated with MS by examining the entire expressed sequence of both genes by single strand conformation polymorphism (SSCP) analysis, using a panel of 71 MS patients and 71 controls. We have also re-examined the VNTR region in patients and controls. Three base changes were found in the human PLP gene and nine base changes in the human MBP gene; these were essentially equally distributed between patients and controls. No preferential distribution of various alleles of the VNTR between patients and controls was found. Although intronic and regulatory regions have not been examined, it would appear unlikely that mutations in these genes coding for the two major CNS myelin proteins contribute significantly to genetic susceptibility to MS.

Adult↗

Case-control study of neuroleptic malignant syndrome.

OBJECTIVE: The authors performed a case-control study of neuroleptic malignant syndrome to identify potential risk factors. METHOD: Twenty-five patients with neuroleptic malignant syndrome were matched with 50 comparison subjects on age, sex, primary psychiatric diagnosis, and time of admission to the hospital. The records of all subjects were reviewed independently by two researchers for information on postulated risk factors. Exploratory direct comparisons of the two groups were followed by a conditional logistic regression analysis. RESULTS: Patients with neuroleptic malignant syndrome were more likely to be agitated or dehydrated before the development of neuroleptic malignant syndrome, often needed restraint or seclusion, and received larger doses of neuroleptics soon after hospitalization. Previous treatment with ECT increased vulnerability. CONCLUSIONS: The prevalence of neuroleptic malignant syndrome may be reduced by avoiding large doses of neuroleptics over short periods in the management of acute psychosis and by paying adequate attention to the patient's hydration and electrolyte status.

Adult↗

Ethical considerations in the management of asylum seekers on hunger strike.

Hunger strikes have confronted physicians with complex ethical dilemmas throughout history. Asylum seekers under threat of forced repatriation have emerged as a new category of hunger strikers, posing novel challenges for management. The management of 3 Cambodian asylum seekers on hunger strike admitted to a hospital in Sydney, New South Wales, Australia, posted important ethical dilemmas for the physicians and mental health experts involved in their care. Several factors confounded the task of assessment and decision making, including language and cultural barriers, the patients' past exposure to persecution by authorities, and the complexities of the legal procedures being pursued. Different rules appeared to govern the actions of the hunger strikers, the medical team, and the immigration authorities, creating a ¿malignant triangle¿ of mounting confrontation. Recent recommendations for the management of asylum-seeking hunger strikers include the appointment of an external physician of confidence and the writing of a confidential advance directive specifying the hunger striker's wishes about resuscitation in the event of collapse. In addition, we consider the value of constituting an ad hoc ethics committee to advise the responsible physician on points of conflict in managing the hunger strike. The advantages and limitations of these proposals in relation to the particular cultural, historical, and contextual issues relevant to asylum seekers are examined herein.

Advance Directives↗

Comparative validity of two measures of psychomotor function in patients with severe depression.

Psychomotor function is a key construct in depressed patients and two measures have been developed for systematic rating. Parker and colleagues utilise an observer-rated scale (CORE) while the scale (DRRS) developed by Widlöcher assesses motor and ideational aspects. Association between the scales and their relative capacity to predict ECT response were investigated in a sample of 81 depressed patients. Both predicted ECT response. While the CORE scale rates a wider variety of phenomena (including non-interactiveness and agitation) and does not rely on the subject's capacity to report aspects of their cognitive function, the study supports the predictive and comparitive validity of both scales.

Adult↗

A novel MAP kinase phosphatase is localised in the branchial arch region and tail tip of Xenopus embryos and is inducible by retinoic acid.

Using a differential display strategy, we have isolated a cDNA corresponding to a mRNA which is induced by retinoic acid treatment of late gastrula Xenopus embryos, and much more strongly induced by retinoic acid and cycloheximide. The cDNA, designated X17C, encodes a novel mitogen-activated protein (MAP) kinase phosphatase of 378 amino acid residues which is only distantly related to other known MAP kinase phosphatases. In normal embryogenesis, the X17C mRNA is expressed after the midblastula transition and accumulates during gastrulation. In neurula and tailbud stage embryos the mRNA is localised in two domains, one in the anterior region of the embryo, and one at the tail tip. When expressed from synthetic mRNA injected into oocytes, the X17C protein is found within the cytosolic fraction and not in the nucleus. The X17C protein dephosphorylates and inactivates Xenopus MAP kinase in oocytes stimulated to undergo maturation by progesterone. We indicate the application of X17C as a tool for interfering with MAP kinase signaling in somatic cells of embryos, using FGF receptor-mediated MAP kinase activation in animal cap explants.

Amino Acid Sequence↗

Temporal integration of events within and between the cerebral hemispheres.

The effect of interhemispheric transmission time (IHTT) on temporal perception was investigated by comparing simultaneity thresholds under unimanual and bimanual stimulation conditions. In the unimanual conditions the tactile stimuli were delivered to the same hand and were received by the same hemisphere, but in bimanual conditions, where stimuli were delivered to different hands, interhemispheric communication was necessary in order to compare the timing of the two stimuli. Randomised order of stimulating the fingers of the hands was compared with consistent stimulation of each hand. Previous studies have used only consistent stimulation. Thirty-two undergraduate university students (16 males and 16 females) were tested. Bimanual simultaneity thresholds were significantly higher than unimanual. Previous research showing an absence of laterality effects for simultaneity judgements was confirmed, supporting a hemispheric equivalence model of temporal processing. Simultaneity thresholds were not affected by randomisation of stimulus location, indicating that expectancy effects were not responsible for the difference between bimanual and unimanual thresholds. The implication of these findings is that temporal perceptions are affected by the process of interhemispheric transmission.

Adolescent↗

Prediction of ECT response: validation of a refined sign-based (CORE) system for defining melancholia.

BACKGROUND: The clinical validity of melancholia has been argued on the basis of its capacity to predict response to electroconvulsive therapy (ECT). We have argued that a sign-based (CORE) rating system of psychomotor disturbance can identify patients with melancholia. Therefore, the clinical validity of the CORE system was tested here in terms of its capacity to predict response to ECT. METHOD: The response of 81 patients with primary affective disorders to an individualised course of ECT was investigated. CORE scores and other clinical predictors were evaluated in terms of their capacity to predict effect size changes in symptoms and disability. RESULTS: CORE scores predicted ECT response, as did the presence of psychotic features. The combination of marked psychomotor change (high CORE scores) and psychotic features predicted the best response to ECT. CONCLUSION: This study supports the clinical validity of the CORE system for diagnosing melancholia.

Aged↗

Multiple supernumeraries: the importance of clinical and radiographic follow-up.

The occurrence of multiple supernumerary teeth is a rare phenomenon. Three cases of multiple supernumeraries are presented which illustrate problems which may arise during long-term follow-up: resorption of adjacent teeth, enlargement of the follicles, movement of the unerupted teeth and development of further supernumeraries. These cases highlight the importance of adequate initial surveillance, anticipation of potential problems, assessing the risk-benefits of surgery and long-term monitoring, in some cases following the surgical removal of supernumeraries.

Adolescent↗