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Biomedical subjects

M McKenzie

Publications and source records attributed to M McKenzie.

71 records · Page 4Linked to original sources
PubMed1978

A human plasma component that binds benzo(a)pyrene.

A component capable of binding benzo(a)pyrene was measured in plasma from cigarette smokers and nonsmokers. This plasma fraction was found to have a high specificity of binding to benzo(a)pyrene, bound benzanthracene competitively with benzo(a)pyrene, and was positively correlated (r = 0.861, p less than 0.001) with the capacity of the individual subject's lymphocytes to be induced for AHH activity in culture. An inverse correlation (r = -0.957, p less than 0.001) between the presence of the plasma component in lung cancer patients and the capacity of lung cancer patients' lymphocytes to be induced in culture is unexplained at this time. A benzo(a)pyrene-binding fraction was not found in induced or uninduced cultured lymphocytes from smokers or nonsmokers, or in homogenates of lung excisional tissue from smokers with or without primary lung cancer.

Aryl Hydrocarbon Hydroxylases↗
PubMed1978

Steroid hydroxylase induction in cultured human lymphocytes: effects of the menstrual cycle.

Steroid hydroxylases (SAH) are inducible in cultured human lymphocytes following treatment with estradiol-17beta. The enzyme systems induced are carbon monoxide sensitive and convert estradiol-17beta to a metabolite chromatographically indistinguishable from estriol. The level of inducibility of SAH varies drastically over a normal menstrual cycle with maximum induction in the late follicular phase and minimum induction during the luteal phase. The use of an oral contraceptive containing both a synthetic progestogen and ethynyl estradiol reduced SAH induction levels to those typically seen during the luteal phase of the menstrual cycle.

Cells, Cultured↗
PubMedDate not supplied

Family grief therapy: a preliminary account of a new model to promote healthy family functioning during palliative care and bereavement.

The family is usually the primary provider of care for the terminally ill patient with cancer or other serious progressive illness. The way in which such a family functions is a major determinant of psychological well-being for its members. Through screening with the Family Relationships Index (FRI) (Moos and Moos, 1981), dysfunctional families and those at risk can be identified, and then helped to achieve better family functioning, thus improving psychosocial outcome of their grief. In this paper, we describe the techniques and themes involved in the application of our empirically developed model of family grief therapy, designed as a preventive intervention for use in the setting of palliative care and bereavement.

Adaptation, Psychological↗
PubMedDate not supplied

Transfusion-acquired cytomegalovirus infection in neonates. A prospective study.

The incidence of cytomegalovirus (CMV) infection was determined in 114 transfused neonates of any birthweight born to CMV antibody-negative mothers. In a second phase of this study, an additional 28 transfused infants weighing less than 1250 g, born to both CMV antibody-negative and antibody-positive mothers, were followed. All infants underwent weekly virus culture and monthly serology during hospitalization and at 6 to 12 weeks after their last transfusion. Only one of 126 (0.8%) seronegative infants and one of 16 (6.3%) seropositive infants developed CMV infection. If the assumption is made that the CMV-infected infant received only 1 unit of infectious blood, the risk of transfusion-acquired CMV infection to seronegative infants is 0.16 percent per cellular unit transfused or 0.37 percent per seropositive cellular unit transfused. Despite similarities in the prevalence of CMV antibody in the donor population, the age of blood products used, and the mean number of donor exposures, a significantly lower incidence of CMV infection was found in the seronegative transfused infants than that in two previously published studies (p less than 0.01, p less than 0.001). Because no mortality and very little morbidity could be attributed to transfusion-acquired CMV infection in the nurseries, the authors can see no justification for the provision of specialized blood components for the prevention of CMV infection in this patient population.

Antibodies, Viral↗
PubMedDate not supplied

Skin blood flow changes in response to intradermal injection of bupivacaine and levobupivacaine, assessed by laser Doppler imaging.

BACKGROUND AND OBJECTIVES: The vascular effects of local anesthetics are important determinants of their therapeutic activity. Drugs that vasoconstrict have the potential clinical advantages of limited systemic uptake and prolonged duration of effect. The aim of this study was to assess quantitatively the cutaneous vasoactivity of racemic bupivacaine and one of its enantiomers, levobupivacaine. METHODS: Four concentrations of each drug (0.1 mL each of 0.125%, 0.25%, 0.5%, and 0.75%), as well as normal saline, were injected intradermally into randomly assigned sites on the forearms of 10 volunteers. We measured skin blood perfusion using laser Doppler imaging before injection and at 2.5, 10, 20, 40, 60, and 90 minutes thereafter. RESULTS: Both drugs produced a rapid, dose-dependent increase in skin perfusion (P <.001). Saline also caused an increase in perfusion, although less sustained. By 40 minutes, most responses had returned to baseline levels. However, after this time, perfusion continued to decrease, below baseline, for both bupivacaine and levobupivacaine. The exception to this was 0.75% bupivacaine, the response to which was significantly higher than the same concentration of levobupivacaine over this later period (P <.05). CONCLUSIONS: Bupivacaine and levobupivacaine both have a biphasic effect on skin microvessels. The vasoconstriction observed after 40 minutes may occur when the quantity of drug remaining at the administration site has decreased to a lower level. The continued vasodilatation caused by bupivacaine is more difficult to interpret. The results suggest that these local anesthetics cause vasodilatation at high doses and vasoconstriction at lower, subclinical doses. This hypothesis and the clinical relevance of these effects warrant further investigation.

Administration, Cutaneous↗
PubMedDate not supplied

Trends and sources of nosocomial fungaemia.

Concurrent surveillance of blood culture isolates in a 1000-bed tertiary care hospital over a 7-year period from 1986 to 1993 identified 102 episodes of nosocomial fungaemia, representing 6.6% of all episodes of nosocomial bloodstream infections and 0.49/1000 admissions. No significant change in the frequency, rate, source or microbial aetiology of nosocomial fungaemia occurred over the 7-year period. Candida albicans accounted for 74%, followed by Candida (Torulopsis) glabrata (8%), C. parapsilosis (7%), C. tropicalis (3%), C. lusitaniae (2%), C. krusei, Malassezia furfur Saccharomyces cerevisiae, Hansenula anomala and Cryptococcus albidus (one each). 'Primary' fungaemia, usually attributed to intravascular catheters, was considered to be the source in 65% of cases, with 64% of these patients receiving total parenteral nutrition (TPN). Other important sources of infection included the urinary tract (11%), the gastrointestinal tract (8%) and the respiratory tract (7%). Sixty-four % of patients were in one of the hospital's seven intensive care units (ICUs) when their infection developed, the neonatal ICU and adult medical/surgical ICU each accounting for 21%. Only 7% of cases were associated with neutropenia and another 14% with malignancy or immunosuppression. Death occurred within 7 days of diagnosis of fungaemia in 23 cases. In eight instances, fungaemia was considered the main cause of death. We conclude that in our hospital nosocomial fungaemia is largely caused by C. albicans, occurring in association with intravascular catheter use and TPN in ICU patients. Most cases are not associated with recognized immune defence defects. Fungaemia is associated with a high short-term mortality rate.

Adult↗
PubMedDate not supplied

Peritonitis due to Stenotrophomonas maltophilia in patients undergoing chronic peritoneal dialysis.

The occurrence of cases of Stenotrophomonas maltophilia peritonitis in chronic peritoneal dialysis (PD) patients prompted a review of our experience with this condition. A search of microbiology records revealed seven episodes of S. maltophilia peritonitis in 7 patients in 1996 - 3.8% of all PD patients - compared to no cases in 1994 and 1995 (p = 0.01). Patients ranged in age from 16 to 64 years; there were 3 males and 4 females. Six of seven episodes of peritonitis were community acquired and one was hospital acquired. No temporal clustering of cases was seen. Patients were from different urban and rural communities. Patients used the same commercially supplied dialysate fluid, different dialysis techniques, and were taught a no-touch technique for connection. Treatment of peritonitis required removal of the Tenckhoff catheter in 4 of 7 cases. Fingerprinting of six available isolates by polymerase chain reaction using primers derived from the conserved region of the 16/23Sr RNA gene sequence and pulsed field gel electrophoresis revealed all to be unique strains. A case-control study comparing 7 S. maltophilia cases to 21 PD controls showed case patients to be younger and more likely to be on immunosuppressive therapy. We conclude that S. maltophilia has emerged as an important cause of peritonitis in our continuous ambulatory PD population. Evidence to date suggests community acquisition with no evidence of a common source.

Adolescent↗
PubMedDate not supplied

The carers of hospital in the home patients focus on clinical processes, procedures and the prediction of deterioration.

The aim of this study was to explore the psychological processes and information needs in a group of 78 Hospital-in-the-Home (HITH) carers, randomly selected from two university teaching hospital HITH programs in Melbourne. Semi-structured interviews were conducted and explored with a computerised lexical thematic content analysis program. The results revealed that psychological themes of carers were mainly related to HITH clinical processes, procedures and the prediction of complications or deterioration of the patient. Carers indicated that they needed further information on the patients' clinical conditions, emergency procedures and how to detect deterioration. The implication for HITH nurses is that information provided to HITH carers should at least include these topics. The information needs of HITH carers appear to be different to those of the carers of individuals with chronic illness, consequently, nurses need to develop very specific patient and carer information materials for the HITH setting.

Acute Disease↗
PubMedDate not supplied

Chemotherapy standards for hospital in the home: how useful?

The process of developing practice standards is complex and resource intensive. The aim is to produce standards that meet the practicalities of clinical practice, are meaningful and achievable and that enhance the quality of patient care. This article details the process of developing chemotherapy standards for Hospital in the Home (HITH) and describes the results of a pilot project and the implications for nursing practice in this relatively new area of care delivery. Five Melbourne metropolitan Hospital in the Home (HITH) programs participated in the pilot process and evaluated the standards against their own programs. There was a wide variation in the skill sets nurses required depending on the structure of the HITH program. There were differences between programs in the nature of the interventions provided at home, documentation of treatments and points of contact for patients out of hours. Areas of concern identified by staff in the participating programs included the level of detail the standards required for assessment of the patients' home as an appropriate site to administer chemotherapy and the qualifications required by staff managing HITH chemotherapy patients.

Community Health Nursing↗
PubMedDate not supplied

Amniotic fluid polarization of fluorescence and lecithin/sphingomyelin ratio decision criteria assessed.

A negative finding of amniotic fluid (AF) phosphatidyl glycerol (PG) does not eliminate the need for determining the lecithin/sphingomyelin ratio (LSR). We use a novel approach to classify fetal lung maturity (FLM) data, and to validate the fluorescence polarization (FP) surfactant assay (Abbott), which replaces the PG assay and reduces the frequency of repeat LSR. This method finds the values (decision points) of these tests that allow for classifying the data with least errors. These tests best identify the risk of respiratory distress syndrome (RDS) from fetal lung immaturity. We find the decision values for tests by exploring the data for information content and optimize their selection using group-based reference. We previously defined normal reference as the maximum entropy set with no information. The uncertainty resolved by information provided in the data allows formation of syndromic classes. This is greatest at the values for the variables (decision-points) associated with the greatest decrease in entropy. Decision-values found for PF, EGA, PG, LSR that classify amniotic fluids into the mature and not-mature classes are in agreement with the results of ROC analysis. We validate the replacement of PG by the PF method. We also find a level of FP below which LSR might be required to resolve uncertainty and above which the FP indicates maturity. We confirm the ability to evaluate fetal maturity methods using information analysis.

Amniotic Fluid↗
PubMedDate not supplied

Increasing the availability of vasectomy in public-sector clinics.

A program designed to improve the availability of vasectomy in public-sector clinics trained physicians at 43 facilities in no-scalpel vasectomy between 1993 and 1995. Among the 38 clinics that responded to a follow-up survey in 1996, the number of clinics providing vasectomies rose from 23 to 32, an increase of almost 40%, while the number of vasectomies performed rose by 18%. Seventeen of the 32 clinics performed more vasectomies after the training; 10 of the 17 had not previously provided the procedure. In-depth interviews with staff from seven sites that experienced large caseload increases and from seven that experienced decreases identified three elements for the successful establishment or expansion of vasectomy services-sufficient numbers of trained providers, funds to subsidize vasectomies for men who cannot afford them and activities to raise awareness about the availability of low-cost or free vasectomy.

Ambulatory Care Facilities↗