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Biomedical subjects

T G Murrell

Publications and source records attributed to T G Murrell.

At least 19 recordsLinked to original sources
PubMed1995

The potential for oxytocin (OT) to prevent breast cancer: a hypothesis.

This hypothesis proposes that carcinogens in the breast are generated by the action of superoxide free radicals released when acinal gland distension, under the influence of unopposed prolactin, causes microvessel ischaemia. Inadequate nipple care in the at-risk years leads to ductal obstruction preventing the elimination of carcinogens from the breast. The regular production of oxytocin (OT) from nipple stimulation would cause contraction of the myoepithelial cells, relieving acinal gland distension and aiding the active elimination of carcinogenic fluid from the breast. Mechanical breast pump stimulation causes an increase in plasma OT levels in the luteal but not in the follicular phase of the menstrual cycle. OT production upon nipple stimulation in the luteal phase of premenopausal, non-lactating women may be protective against the high rates of mitotic breast cell division noted at this time via the potential to block the effect of oestrogen. The epidemiology of breast cancer suggests that lengthy lactation time is beneficial. Sexual activity in nulliparous women also protects and OT levels have been shown to rise with orgasm in women and in men. OT systems in the brain are intricately linked to oestrogen and progesterone levels, and it is possible that these hormones may modify the OT secretory response both centrally and through an effect on the sensitivity of the breast. OT production with nipple care and in sex and lactation, and the reduction in cycling ovarian hormones that occurs with pregnancy, may all be important preventative factors in the development of breast cancer both pre- and post-menopausally.

Breast Neoplasms↗
PubMed1992

Verbal interactions in general practice. Information, support and doctor satisfaction.

OBJECTIVE: The general practice encounter can be seen as an exchange of information aimed at relief of the patient's presenting symptoms, and it is acknowledged that this goal can most effectively be achieved within the context of the professional's emotional support of the patient. We sought to describe the processes of information exchange and emotional support in detail, and to explore any differences in the speech pattern which were related to the doctors' lesser satisfaction with some consultations. DESIGN: Transcripts of general practice consultations (n = 143) from five medical practitioners were coded and analysed. MAIN OUTCOME MEASURES: The verbal interactions of the consultation were described in categories: for doctors, emotional support, informational support, and diagnostic activity; and for patients, relationship oriented and task oriented. Doctors also rated their satisfaction with each consultation. RESULTS: About two-thirds of the speech by both parties was found to be devoted to information exchange in the forms of diagnosis and medical advice, and the rest to the relationship between the participants. Doctors' satisfaction ratings (extremely satisfactory or otherwise) could be predicted from speech and activity variables by means of logistic regression. CONCLUSIONS: This study describes the verbal interaction which is the vehicle for medical helping in general practice, and it forms a foundation for needed research on how certain features of the verbal interaction are related to quality of care.

Adult↗
PubMed1991

Epidemiological and biochemical support for a theory on the cause and prevention of breast cancer.

Damage to the breast epithelium by chemical carcinogens as products of oxygen free radical release can lead to fibroblast proliferation, hyperplasia of epithelium, cellular atypia and breast cancer. Chemical carcinogens may accumulate in breast fluid in the non-lactating breast consequent to superoxide free radical production which occurs via the adenosine triphosphate (ATP) hypoxanthine pathway. This pathway is initiated by hypoxia of local tissue. Under hypoxic conditions ATP is broken down to form hypoxanthine. Hypoxanthine itself is broken down to produce xanthine and then uric acid. This results in the production of superoxide free radicals, the products of which are carcinogenic. The development of localized hypoxia, which is central to this hypothesis, is caused by acinal gland distention from fluid secreted by raised prolactin levels in the absence of oxytocin. Stimulation of the nipple in a non-lactating breast may raise plasma oxytocin and lower plasma prolactin levels. Contraction of the myoepithelial cells of the breast under the influence of oxytocin would relieve distention of the acinal glands and thus reduce hypoxia and the generation of lipid peroxidoses as products of free radical damage. The epidemiology of breast fibrosis and cancer support the notion that lack of nipple stimulation over time may be a significant variable. A review of this literature linked with current biochemical work on fibrosis and carcinogenesis suggest that draining the breasts of the products of superoxide free-radical release by the encouragement of regular nipple erections may prevent such breast disease.

Breast↗
PubMed1991

Speech patterns and satisfaction in diagnostic and prescriptive stages of general practice consultations.

With a general goal of establishing indicators of the quality of the helping relationship within medical consultations, we recorded and analysed verbal interactions in general practice consultations, in two studies. The diagnostic and prescriptive stages of the consultation were analysed separately, first with doctor satisfaction as the outcome and then, with a second sample of doctors, with both doctor and patient satisfaction as outcomes. Patients and doctors were found to have somewhat different views of what made a highly satisfactory consultation. The most satisfying consultations for doctors were those in which the medical problem and its solution seemed clear; patients felt most satisfied with consultations where they had discussed their own experiences and opinions during the second, prescriptive stage of the consultation.

Consumer Behavior↗
PubMed1991

Signs, symptoms, and the new descriptors.

Data from 143 consultations in general practice were assessed by factors relevant to the four-category descriptive system developed by the Royal Australian College of General Practitioners. It seems that there is no relationship between consultation length, apparent symptom seriousness or the occurrence of a physical examination. Suggestions are offered for improving the clarity of consultation descriptor categories.

Diagnosis↗
PubMed1990

Multiple sclerosis--one manifestation of neurobrucellosis?

There is good geographic evidence that an environmental factor is implicated in the aetiology of multiple sclerosis (MS). Controversy surrounds the interpretation of many studies supporting notions on whether the disease has greater prevalence in urban or rural communities. Rather than focus on residence at birth, in teenage years or at the time of study, analyses of MS mortality by occupation and a case control study to define exposure to animal farm products is thought to shed light in this controversy. The conclusion reached from the results of these studies is that exposure to farm animals or raw products is a common denominator in the aetiology of MS. A literature search for references of zoonotic disease with neurological symptoms produced a range of papers on brucellosis. A study of the literature on neurobrucellosis supports the hypothesis on clinical grounds. Finally, blood serum studies of Brucella exposure in a series of MS subjects and controls is described. These epidemiological studies support the hypothesis, that central nervous system involvement from exposure to brucellosis, may present with the features of multiple sclerosis.

Brucellosis↗
PubMed1990

The reducible risks of sudden infant death syndrome (SIDS).

The general practitioner rarely encounters a case of SIDS in practice. However, every young parent fears such a tragedy. The authors explore known risks for a SIDS death which are reducible. In particular, the infant between 2 and 4 months of age is at greatest risk from factors relating to poverty and seasonality. Counselling parents about such risks is an important role for the general practitioner.

Cause of Death↗
PubMed1990

The role of the GP in the management of chronic disease. Diabetes as a model.

Chronic disease is increasing as a percentage of all illnesses in Australia's health care system, in part because of the ageing of the population. New strategies are required to help manage these often incurable diseases. The general practitioner is well equipped to provide management expertise for chronic disease, provided he or she has access to community based allied health professionals.

Chronic Disease↗
PubMed1987

A hypothesis concerning Clostridium perfringens type A enterotoxin (CPE) and sudden infant death syndrome (SIDS).

This study identifies the presence of Clostridium perfringens type A enterotoxin (CPE) in some gastrointestinal and serum samples from babies who had died of the Sudden Infant Death Syndrome (SIDS) and other causes. On occasion antibodies to this toxin were identified in sera. CPE is parasympathomimetic in its action. In the adult food poisoning model it is produced when the organism sporulates in vivo. This leads to speculation as to whether this toxin may play an ante-mortem role in the dying process of infants, either in the agonal stages or as a causative factor in SIDS.

Bacterial Toxins↗
PubMed1986

A review of the sheep-multiple sclerosis connection.

This paper reviews a notion that the prevalence of multiple sclerosis is high in global areas where sheep populations are concentrated. Pilot studies are reported to serum antibodies in humans to three sheep diseases; focal symmetrical encephalomalacia (FSE), maedi visna and sarcocystis. In MS patients and controls antibodies were not found to the epsilon neurotoxin of the FSE organism, Clostridium welchii type D and to a caprine retrovirus that is closely related to maedi-visna virus. However, 34% of MS and control patients had antibodies to the protozoan parasite Sarcocystis spp., tissue cysts of which contain a powerful neurotoxin, sarcocystin. It is suggested that epidemiological MS prevalence rates for country areas of southern Australia require further study along with an examination for the prevalence of MS in vegetarians.

Adult↗
PubMed1983

Pigbel in Papua New Guinea: an ancient disease rediscovered.

A hypothesis suggested in this paper is that pigbel, or enteritis necroticans was a common disease in mediaeval Europe when human habitats, food hygiene, protein deficiency and periodic meat feasting formed the basics of village life as they do in many Third World cultures today. Based on the Papua New Guinea experience with pigbel, it is suggested that health authorities should look closely at the epidemiology of the acute surgical abdomen in such communities. Enteritis necroticans may be the important predisposing lesion to mid-gut volvulus, jejunal and ileal ileus and other forms of small bowel strangulation in communities where protein deprivation, poor food hygiene, epochal meat feasting and staple diets containing trypsin inhibitors co-exist. Such human habitats occur in Central South America, Western Pacific, Asian and South-East Asian cultures. Isolated outbreaks of necrotising enteritis have been reported from Uganda, Malaysia and Indonesia but as yet no systematic epidemiological studies of the prevalence of small bowel strangulations have been described in the surgical literature of Third World countries. Now that enteritis necroticans is preventable by vaccination such studies should be undertaken.

Abdomen, Acute↗
PubMed1980

Scanning electronmicroscopy of the jejunum in enteritis necroticans.

Intestinal tissue resected at laparotomy from patients in Papua New Guinea at various clinical stages of enteritis necroticans, locally known as pig-bel, has been examined under the scanning electronmicroscope. Evidence obtained from parallel studies of experimental infection in pigs is presented. Progressive destruction of the intestinal mucosa was seen during the course of the disease in man. Numerous filamentous rods morphologically consistent with the appearance of Clostridium perfringens type C, were seen to be attached the affected areas of gut and were associated with the necrotic tissue. The mechanism of pathogenicity includes a stage of attachment to the surfaces of jejunal villi, local multiplication, and the production of beta toxin which may be protected from tryptic digestion by the inadequacy of pancreatic protease production in susceptible subjects and by the ingestion of a trypsin inhibitor. The association of the condition with pork feasting is discussed.

Adolescent↗