Intracardiac transplantation of a mixed population of bone marrow cells improves both regional systolic contractility and diastolic relaxation.

BACKGROUND: Pre-clinical and clinical studies suggest that transplantation of bone marrow-derived stem cells can improve global cardiac function. However, no quantitative assessment of regional systolic contraction and correlation with phenotype has been made. Therefore, we used our model of cryoinfarcted rabbit myocardium for intracardiac transplantation of a mixed population of bone marrow-derived cells and assessed both regional function and myogenic conversion of the cells. METHODS: Nineteen New Zealand white rabbits underwent cryoinjury of the left ventricle. Autologous bone marrow (BM) cells were expanded in vitro. After 2 weeks, either 1 x 10(8) mixed BM-derived progenitor cells (BM group, n = 11) or vehicle (control group, n = 8) were injected into the cryoinjured region. Regional systolic function was measured using micromanometry and sonomicrometry before and 4 weeks after cell injection; cell phenotype was evaluated histologically. RESULTS: All animals in the BM group significantly improved both systolic shortening (0.11 +/- 0.7 vs -0.05 +/- 0.05 mm in the control group, p < 0.05) and regional stroke work when compared with control (9.6 +/- 2.4 vs -1.2 +/- 1.2 mm . mm Hg, p < 0.003). In addition, the BM group had improved global diastolic function, as measured by minimum dP/dt and end-diastolic pressure. On histologic assessment, BM cells differentiated toward a myogenic phenotype. CONCLUSIONS: Transplanting a mixed population of marrow-derived cells that can adopt a myogenic phenotype improves regional contractility and diastolic relaxation after myocardial infarction.     

Effect of liposome surface charge on the stability of technetium (99mTc) radiolabelled liposomes

Using liposomes radiolabelled by the 99mTechnetium-stannous chloride technique we have investigated the effect of surface charge on the stability of the isotope in vitro and in vivo. Dialysis of 99mTc-labelled positive, negative and neutral liposomes, which had been incubated in either saline or normal rat serum showed no significant loss of the isotope from the liposome surface with only 2 per cent of the isotope dialysed. A comparison of gel chromatography with dialysis confirmed that most of the isotope remained attached to the liposome surface, but it did reveal greater loss of the isotope, between 15 and 23 per cent. The liposome clearance rates obtained from 125I-egg phosphatidylcholine (EPC) and 99mTc dual-labelled positive or neutral liposomes were significantly different. The 99mTc marker was cleared five times faster from the positive liposomes and twice as fast from the neutral liposomes as the 125I-EPC integral membrane marker. The 99mTc attached to liposomes with a negative surface charge was stable in vivo and had the same clearance rate from the circulation as the 125I-EPC marker. These results indicate that the commonly used in vitro techniques for assessing liposome radiolabel stability are unsuitable for predicting the stability of the 99mTc in vivo.     

Determinants of symptom interval in childhood cancer.

The duration of symptoms before diagnosis (lag time) was defined for 184 of 236 children diagnosed as having a malignancy at the Royal Hospital for Sick Children, Edinburgh for the time period January 1982 until December 1990. The natural logarithm of the lag time was correlated with age, gender, diagnostic group, white cell count in acute leukaemia, clinical stage of disease in solid tumours, and event free survival. Age was significantly associated with lag time, older children presenting later. In the diagnostic groups, mean lag time ranged from 2.8 weeks in nephroblastoma to 13.3 weeks for brain tumours. Diagnostic group was predictive for lag time after adjustment for age, with for example, a significantly longer lag time for those with brain tumours. However lag time was not predictive of event free survival and it is likely that lag time has other major determinants. When compared with previous studies, there also appears to be a regional variation in lag time for diagnostic groups. It seems likely that this is a reflection of geographical difference in the structure of health systems and is therefore yet another important determinant.     

Parkinson's disease and exposure to rural environmental factors: a population based case-control study

To determine whether a history of exposure to rural environmental factors leads to an increased likelihood of developing idiopathic Parkinson's disease, we conducted a case-control study of 130 cases and 260 randomly selected community controls (matched with the cases by sex and age +/- 2.5 years at a ratio of 2 controls: 1 case) in the city of Calgary. The data were collected by personal interviews and were analyzed using conditional logistic regression for matched sets. The ages of the cases ranged from 36.5 to 90.7 years (mean = 68.5 +/- 11.3 years). The mean age at diagnosis was 61.1 +/- 12.4 years. The mean duration of disease was 7.8 +/- 0.6 years. Eleven (9.1%) cases were diagnosed before age 40. In this sample from the Province of Alberta, Canada, no significant increase in risk for Parkinson's disease was associated with a history of rural living, farm living, or well water drinking in early childhood or at any time during the first 45 years of life.     

Determinants of health-service use by low-income people.

Poverty influences health status, life expectancy, health behaviours, and use of health services. This study examined factors influencing the use of health-related services by people living in poverty. In the first phase, 199 impoverished users of health-related services in 2 large Canadian cities were interviewed by their peers. In the second phase, group interviews with people living in poverty (n = 52) were conducted. Data were analyzed using thematic content analysis. Diverse health-related services were used to meet basic and health needs, to maintain human contact, and to cope with life's challenges. Use of services depended on proximity, affordability, convenience, information, and providers' attitudes and behaviours. Use was impeded by inequities based on income status. To promote the health of people living in poverty, nurses and other health professionals can enhance the accessibility and quality of services, improve their interactions with people living in poverty, provide information about available programs, offer coordinated community-based services, collaborate with other sectors, and advocate for more equitable services and policies.     

Incidence of hospital-acquired infections associated with caesarean section

A retrospective cohort study was conducted to determine the incidence of post-caesarean infections in a Canadian community teaching hospital using computer algorithms designed for the diagnosis of nosocomial infections. Inferential chart review was done on 1335 women delivered by lower-segment caesarean section (793 primary and 542 secondary) at the Calgary General Hospital between January 1985 and April 1988. The overall infection rates were 42·1 and 46·1% for women delivered by primary and secondary caesarean section, respectively. Incisional surgical wound infection accounted for the largest proportion of post-caesarean infections found. Women delivered by primary caesarean section had significantly higher rates of endometritis, deep surgical wound infection and bacteraemia than those delivered by secondary section. All types of post-caesarean infection, except asymptomatic bacteriuria, caused the duration of the post-partum hospital stay to be significantly increased.     

The delivery of preventive services in primary care practices according to chronic disease status.

OBJECTIVES: The current study examined the relationship between chronic disease status and the receipt of cancer preventive services over a 3-year period. METHODS: Adults (n = 4320) cared for by 167 nonacademic physicians in 42 primary care group practices were studied. Medical records were audited for each patient, as were patient responses to two questionnaires assessing health and sociodemographic characteristics. RESULTS: While the odds of having received counseling to obtain regular checkups were increased for men (1.56) and women (1.46) with hypertension, the odds were reduced (range = 0.32 to 0.81) for having received a sigmoidoscopy (women with diabetes or hypertension, men with hypertension or heart disease), fecal occult blood test (men with diabetes or heart disease, women with heart disease), mammogram or counseling about smoking (women with diabetes), clinical breast exam (women with heart disease), and Pap test (women with diabetes or heart disease). CONCLUSIONS: The presence of common chronic health problems in older adults is associated with lower levels of cancer screening services.     

Why patients delay seeking care for cancer symptoms. What you can do about it

Patient delay in seeking care for cancer symptoms is common and well documented by research studies. Fear and denial, lack of information about cancer, and financial considerations all contribute to this delay. Patient education may be an important factor in decreasing the length of delay and thereby improving treatment outcome. By making good use of opportunities for patient education, primary care physicians may positively influence the prognosis of several types of cancer, particularly breast cancer and malignant melanoma of the skin.     

Propofol Increases Contractility during α1a-Adrenoreceptor Activation in Adult Rat Cardiomyocytes

Background: The objective of this study was to identify the extent to which propofol alters intracellular free Ca2+ concentration ([Ca2+]i), myofilament Ca2+ sensitivity, and contraction of individual cardiomyocytes during activation of [alpha]1a adrenoreceptors and to determine the cellular mechanism of action.

Methods: Freshly isolated ventricular myocytes were obtained from adult rat hearts. Myocyte shortening and [Ca2+]i were simultaneously monitored in individual cardiomyocytes exposed to phenylephrine after treatment with chloroethylclonidine ([alpha]1b-adrenoreceptor antagonist) and BMY 7378 ([alpha]1d-adrenoreceptor antagonist). Data are reported as mean +/- SD.

Results: Phenylephrine increased myocyte shortening by 124 +/- 9% (P = 0.002), whereas peak [Ca2+]i only increased by 8 +/- 3% (P = 0.110). Inhibition of phospholipase A2 and phospholipase C attenuated the phenylephrine-induced increase in shortening by 84 +/- 11% (P = 0.004) and 15 +/- 6% (P = 0.010), respectively. Inhibition of protein kinase C (PKC) and Rho kinase attenuated the phenylephrine-induced increase in shortening by 17 +/- 8% (P = 0.010) and 74 +/- 13% (P = 0.006), respectively. In the presence of phenylephrine, propofol increased shortening by 40 +/- 6% (P = 0.002), with no concomitant increase in [Ca2+]i. PKC inhibition prevented the propofol-induced increase in shortening. Selective inhibition of PKC[alpha], PKC[delta], PKC[varepsilon], and PKC[zeta] reduced the propofol-induced increase in shortening by 12 +/- 5% (P = 0.011), 36 +/- 8% (P = 0.001), 32 +/- 9% (P = 0.007), and 19 +/- 5% (P = 0.008), respectively. Na+-H+ exchange inhibition reduced the propofol-induced increase in shortening by 56 +/- 7% (P = 0.001).