Cardiac and neuromuscular implications of left bundle branch block in left ventricular hypertrabeculation/noncompaction

BACKGROUND:

Left bundle branch block (LBB) is frequently found in left ventricular hypertrabeculation/noncompaction (LVHT).

OBJECTIVES:

To compare LVHT patients with and without LBB regarding LVHT location and extension, left ventricular function, symptoms, electrocardiographic findings, prevalence of neuromuscular disorders (NMDs) and mortality during follow-up.

METHODS:

The charts of patients who underwent transthoracic echocardiographic examination at the Krankenanstalt Rudolfstiftung (Wien, Austria) between June 1995 and November 2006 were examined.

RESULTS:

LVHT was diagnosed in 102 patients (30 women) with a mean (± SD) age of 53±16 years (range 14 to 94 years). A specific NMD was diagnosed in 21 patients and an NMD of unknown etiology was diagnosed in 47. The neurological investigation was normal in 14 patients and 20 patients refused the investigation. The 24 patients with LBB were older (61 versus 51 years of age; P<0.01), and suffered from exertional dyspnea (96% versus 59%; P<0.01) and heart failure (79% versus 46%; P<0.01) more often than patients without LBB. LBB patients had less frequent tall QRS complexes (8% versus 47%; P<0.01) and ST-T wave abnormalities (4% versus 50%; P<0.01) than patients without LBB. Patients with LBB had a larger left ventricular end-diastolic diameter (73 mm versus 61 mm; P<0.01), worse left ventricular fractional shortening (15% versus 26%; P<0.01) and more extensive LVHT (1.8 versus 1.5 ventricular segments; P<0.05). The prevalence of NMDs did not differ between patients with and without LBB. Survival did not differ between patients with and without LBB during follow-up.

CONCLUSIONS:

LBB is associated with increased age, decreased systolic function and increased extension of LVHT. Whether LBB is a prognostic factor in LVHT remains speculative.     

Measurement of von Willebrand factor as the marker of endothelial dysfunction in vascular diseases

BACKGROUND:

von Willebrand factor is a blood glycoprotein that is required for normal hemostasis. Its level can be increased by endothelial cell damage.

HYPOTHESIS:

von Willebrand factor is a suitable marker of endothelial dysfunction.

METHODS:

von Willebrand factor activity was determined by ELISA in patients with acute coronary syndromes, acute stroke and chronic vascular diseases, and was compared with the values of healthy controls.

RESULTS:

von Willebrand factor activity of patients in each group was significantly higher (P<0.001) than that of the control group. The values of patients with acute coronary syndrome and acute stroke were significantly higher (P<0.05 and P<0.01, respectively) than those of patients with chronic vascular diseases. von Willebrand factor activity was significantly higher in patients with acute coronary syndrome and acute stroke (P<0.05 and P<0.01, respectively) on the sixth day than on admission.

CONCLUSIONS:

By measuring von Willebrand factor activity, a considerable, significant difference could be found between healthy people and chronic and acute vascular patients. The routine measurement of von Willebrand factor activity in vascular patients as an index of endothelial dysfunction may have clinical importance, because detection of this marker can be a noninvasive way of assisting diagnosis and indicating disease progression.     

Evaluation of haemoglobin, haematocrit, haemolysis, residual protein content and leucocytes in 345 red blood cell concentrates used for the treatment of patients with β-thalassaemia

Background

The aim of this study was to evaluate the quality of red blood cell concentrates obtained from donated whole blood, selected for transfusion therapy of thalassaemic patients, by measuring the following parameters: haemoglobin, haematocrit, percentage haemolysis, residual leucocyte count and residual protein content.

Materials and methods

Overall 345 red cell concentrates were evaluated, of which 205 had been filtered in-line pre-storage and washed and 140 were buffy coat-depleted and used within 2 days of collection. Of the buffy coat-depleted concentrates, 62 were leucodepleted and 78 washed and leucodepleted post-storage all within 2 days of collection. The off-line filters used for the leucodepletion were gamma-irradiated polyester with a pore size of 200 μm. The washing procedure was automated (Haemonetics ACP 215, Braintree, MA, USA). The haematological parameters were evaluated by a blood cell counter (Coulter, Ramsey, IL, USA) and the white blood cell count by cytofluorimetry (FACScan).

Results

Ninety-five percent (194/205) of the red cell concentrates that had been filtered pre-storage and washed, 92% (57/62) of the red cell concentrates that had been leucodepleted post-storage and 94% (73/78) of the those subjected to both treatments had normal values of haemoglobin (>40 g/unit), haematocrit (between 50–70%), percentage haemolysis (<0.8/unit), white cell count (<1×10⁶) and residual protein content (<0.5 g/L). Five percent (11/205) of the red cell concentrates that had been filtered pre-storage and washed, 8% (5/62) of those leucodepleted post-storage after 2 days and 6% (5/78) of those that underwent both procedures had a haemoglobin content <40 g/unit and a haematocrit <50%.

Conclusions

The preparation procedures had been carried out satisfactorily; nevertheless, transfusion therapy with some “low dose” normal units could be less effective and might, therefore, result in greater transfusion requirements in patients receiving such units.     

Impact of the metabolic syndrome on aortic pulse pressure and ascending aortic pulsatility in patients with angiographically normal coronary arteries

BACKGROUND:

Large artery stiffness is a major determinant of pulse pressure (PP), and PP at baseline has been associated with future coronary events.

OBJECTIVE:

To evaluate the impact of the metabolic syndrome on aortic PP and ascending aortic pulsatility (AP) in patients with angiographically normal coronary arteries.

METHODS:

Forty-two patients with the metabolic syndrome and 40 age-matched control subjects without the metabolic syndrome were included in the study. All subjects had normal coronary arteries. Diagnosis of the metabolic syndrome was based on the International Diabetes Federation guidelines published in 2005. Ascending AP was estimated as the ratio of aortic PP to mean blood pressure.

RESULTS:

Aortic PP (59±12 mmHg versus 43±10 mmHg; P<0.001) and ascending AP (0.54±0.10 versus 0.48±0.10; P<0.001) were significantly higher in the metabolic syndrome group. Multiple regression analysis revealed statistically independent relationships between ascending AP and fasting blood glucose, waist circumference and systolic blood pressure (model R²=0.408; P<0.001). The metabolic syndrome, as a whole, was also independently associated with both ascending AP (P<0.01) and aortic PP (P<0.01).

CONCLUSION:

The data showed that the metabolic syndrome is independently associated with increased aortic PP and ascending AP in patients with normal coronary arteries, suggesting aortic stiffness as one of the possible mechanisms underlying the excess cardiovascular risk associated with the metabolic syndrome.     

Relationship of admission hematological indexes with myocardial reperfusion abnormalities in acute ST segment elevation myocardial infarction patients treated with primary percutaneous coronary interventions

BACKGROUND:

Elevated values of mean platelet volume (MPV) and elevated white blood cell (WBC) count are predictors of an unfavourable outcome among survivors of ST segment elevation myocardial infarction (STEMI). However, their relationship with reperfusion abnormalities is less clear.

OBJECTIVE:

To evaluate the value of admission MPV and WBC count in predicting impaired reperfusion in patients with acute STEMI who are treated with primary percutaneous coronary intervention (PCI).

METHODS:

Blood samples were obtained on admission from 368 STEMI patients who underwent successful PCI. According to the 60th minute ST segment resolution ratio, patients were divided into impaired reperfusion and reperfusion groups.

RESULTS:

Impaired reperfusion was detected in 40% of study patients. Patients in the impaired reperfusion group had a higher admission MPV (9.8±1.3 fL versus 8.6±1.0 fL; P<0.001) and a higher WBC count (14.4±5.5×10⁹/L versus 12.1±3.8×10⁹/L; P<0.001) compared with the patients in the reperfusion group. In regression analysis, MPV (OR 2.21, 95% CI 1.69 to 2.91; P<0.001) and WBC count (OR 1.08, 95% CI 1.02 to 1.15; P=0.01) were found to be independently associated with impaired reperfusion. The best cut-off value of MPV for predicting impaired reperfusion was determined to be 9.05 fL, with a sensitivity of 74% and a specificity of 73%.

CONCLUSIONS:

The results indicate that leukocytes and platelets have a role in the mediation of reperfusion injury. In patients with STEMI who are undergoing PCI, admission MPV may be valuable in discriminating a higher-risk patient subgroup and thus, may help in deciding the need for adjunctive therapy to improve the outcome.     

Blood pressure reactions to insulin treatment in patients with type 2 diabetes

BACKGROUND

The initiation of insulin therapy may be easy and uncomplicated in some patients with type 2 diabetes, but in others, mainly in obese patients, problems often arise (ie, poor compliance, worsening B-cell function and/or insulin resistance).

METHODS

As a substudy of a broader investigation concerning hemorheological effects of insulin treatment in insufficiently controlled type 2 diabetes, blood pressure was recorded in 12 patients at baseline, after two months and after four months on insulin.

RESULTS

After two months on insulin, analyses of triglycerides, high-density lipoprotein cholesterol and total cholesterol indicated metabolic improvement (P<0.05 to 0.001) and a surprisingly uniform increase of blood pressure values (P<0.05 to 0.01) was found. At the same time, the serum sodium concentration increased (P<0.01) and was positively correlated to both systolic and diastolic blood pressure (P<0.01). After four months on insulin, blood pressure returned to pretreatment values or lower (P<0.05 to 0.01). Serum sodium also decreased to pretreatment values. No significant changes of the flow behaviour of blood were seen after the initiation of insulin.

CONCLUSIONS

The number of patients was small and the study was not primarily designed to examine blood pressure. The preliminary conclusion from the present study, however, is that the initiation of insulin treatment in poorly controlled type 2 diabetes causes a temporary and possibly clinically significant elevation of blood pressure. A change in renal treatment of sodium caused by insulin may be one of several possible explanations of the results, but further studies are warranted to confirm the findings.     

Effects of storage time and leucocyte burden of packed and buffy-coat depleted red blood cell units on red cell storage lesion

Background

The red cell storage lesion (RCSL) comprises the biochemical and biomechanical changes that take place during red blood cell (RBC) storage, reducing the survival and function of these cells. Contaminating white blood cells have been major contributors to the RCSL. Markers of RCSL, such as CD47 and phosphatidylserine (PS), on RBC are attracting more attention. The aim of this study was to elucidate the effects of storage time and buffy-coat removal on CD47 and PS expression on RBC. Potassium and free haemoglobin levels in the supernatant plasma were also assessed.

Materials and methods

Forty-three red cell concentrates were divided into two groups [Group 1: packed red cells (n=22); Group 2: red cell units from which the buffy-coat had been removed (n=21)] and samples were collected on days 1, 14 and 28. Flow cytometry was used to monitor changes of CD47 and PS expression on RBC over times. Supernatant potassium was measured and percent of haemolysis calculated.

Results

A significant, progressive decrease in RBC CD47 expression during storage was observed in both groups. The decrease in RBC CD47 expression was significantly less in the buffy-coat-removed group of units than in the other group. The percentage of annexin V-positive cells increased significantly in both groups. Buffy-coat depleted components showed less expression of PS only in the early samples. There were significant, progressive increases in percentage of haemolysis and supernatant potassium during storage in both groups.

Conclusion

RBC stored for more than 14 days exhibited reduced CD47 and increased PS. Buffy coat removal reduced the loss of CD47, but had no impact on plasma haemoglobin, potassium or RBC PS exposure.     

Haematocrit is invalid for estimating red cell volume: a prospective study in male volunteers

Background

Although haematocrit and haemoglobin value are concentrations, they are commonly used to guide clinical decisions involving red cell and plasma volumes. A study challenging this convention systematically co-determined and compared these measures.

Materials and methods.

Using a non-radioactive double-tracer technique to assess blood volume components, measurements were taken once in 46 healthy male endurance athletes. The best predictors of blood composition were derived from the first 36 athletes by automated stepwise forward selection of non-invasive metric parameters (age, weight, height, body surface area and body mass index) and the resulting formulae validated in the remaining ten volunteers. Haematocrit, haemoglobin concentration, red cell volume and plasma volume were measured again 4 weeks later in eight randomly selected volunteers.

Results

Red cell volume (2,282±283 mL) did not correlate with either haematocrit (0.42±0.02) or haemoglobin concentration (14.2±0.8, P>0.05, resp.), but was predictable from body surface area (red cell volume [mL]=1,547 × body surface area [m²]–723; r=.88, P<0.01). A similar accuracy was unobtainable using any potential predictor for plasma or blood volume, haematocrit or haemoglobin concentration. Red cell volume showed high intra-individual stability when measured again after 4 weeks, whereas plasma volume oscillated in both directions by up to 22%.

Discussion.

Only red cell volume shows sufficiently stable intra- and interindividual values to be an accurate, objective indicator of normality in blood composition. The measurement technique is feasible in the outpatient setting and this parameter provides effective, robust, and readily available diagnostic information that might be useful in numerous clinical situations. Its clinical significance does, however, remain to be demonstrated.     

The need to label red blood cell units with their haemoglobin content: a single centre study on haemoglobin variations due to donor-related factors

Background

Red blood cell (RBC) transfusions are given as “number of units” without considering the haemoglobin (Hb) content of these units. Donor factors influencing Hb level in whole blood donors and, ultimately, in RBC units have not been studied.

Materials and methods

Donor data for a period of 1.5 years were retrospectively analysed and the effects of age, gender and weight on the Hb level of the donors were determined. The correlation between donor’s Hb concentration with total Hb in the RBC unit was analysed. Additionally, actual Hb content of 125 RBC units was determined. The total Hb content of these RBC units was also mathematically calculated based on the blood donors’ Hb. The ability of this mathematically calculated Hb to predict actual Hb content per RBC unit was then analysed.

Results

The mean Hb level in female donors was 1.79 g/dL lower than in the male donors (p<0.001). Increasing age was associated with a lower mean Hb in the donors (p<0.01), while a higher body weight correlated weakly (r=0.06) but significantly with increased mean Hb (p<0.01). Logistic regression analysis showed that in blood donors, female gender had a stronger influence on lowering the mean Hb than either older age or lower weight. A variation of nearly 100% (42.3–80.8 g Hb per unit) was seen in the total Hb content of the RBC units tested. Mathematically calculated Hb content correlated well (r=0.6; p<0.01) with the actual Hb content of the RBC units.

Discussion

We demonstrated the effect of gender, age and weight on Hb levels in whole blood donors. Dissimilarities in the donor Hb caused nearly 100% variations in the Hb content of the RBC units. It would, therefore, be prudent to label RBC units with their total Hb content. This total Hb content can be predicted fairly accurately from the donor’s pre-donation Hb level.     

Apolipoprotein AV gene polymorphisms (T-1131/C and Ser19/Trp) influence plasma triglyceride levels and risk of myocardial infarction

BACKGROUND:

The importance of an apolipoprotein AV (apoAV) gene for plasma triglyceride (TG) level determination has been shown on transgenic and knockout mice.The influence of apoAV polymorphisms (T-1131/C and Ser19/Trp) on plasma TG levels was evaluated in a representative sample of 1191 men and 1368 women, in 435 patients with myocardial infarction (MI) and in 83 individuals with extreme TG levels (20.4±12.8 mmol/L).

METHODS:

ApoAV variants were analyzed using polymerase chain reaction and restriction analysis.

RESULTS:

T-1131/C variation in the apoAV gene affects plasma TG levels, showing a higher level in C-1131 carriers than in T/T-1131 homozygotes. This association has been observed both in men (P<0.05) and in women (P<0.01). TG levels were also influenced by the Ser19/Trp apoAV genotypes. In both males and females, the Trp19 carriers have higher plasma TGs (P<0.01) than do Ser19 homozygotes. In hypertriglyceridemic patients, the frequency of carriers of the T/C-1131 and C/C-1131 genotypes (32.5% versus 15.4%, P<0.0001) and Ser/Trp19 and Trp/Trp19 genotypes (30.1% versus 14.1%, P<0.0001) was much higher than in the population sample. In a group of MI patients (n=435), the frequency of the disadvantageous homozygous genotypes, with their effect of increasing the TG concentration (C/C-1131 and/or Trp/Trp19), was significantly higher than in the population sample (7.4% versus 2.0%, P<0.00001).

CONCLUSION:

Variation(s) in the apoAV gene play an important role in the genetic determination of plasma TG levels and influence the risk of MI.     

Prognostic effects of pulmonary hypertension in patients undergoing cardiac resynchronization therapy

Background

Aim of this study is to investigate the impact of elevated pulmonary artery systolic pressure (PASP) on mortality and the clinical outcome after cardiac resynchronization therapy (CRT).

Methods

Ninety-three patients with heart failure were enrolled into this study, and all of them have been treated by CRT for more than 6 months. Based on the level of preoperative PASP, they were divided into three groups (Group I: PASP>50mmHg, n=29; Group II: 30mmHgResults①Eight (28%), one (6%) and eight (17%) patients died in-group I, II and III respectively. Among those patients, 5 in group I and 1 in group III died of heart failure, while the patient in group II died of sudden death. ②In all three groups, CRT significantly improved heart function evaluated by NYHA heart function class and 6 minutes walking distance (6-MWT) (P<0.01). The improvement was more significant in group III than group I (P<0.01). ③At 3 months after CRT, Left ventricular ejection fraction (LVEF) increased significantly in Group III (P<0.01), but not in Group I or II (all P>0.05. At 6 months after CRT, LVEF increased significantly in all three groups (all P<0.05).

Conclusions

Elevated PASP has no prognostic effects on heart function improvement in patients undergone CRT. However, it was associated with worse LV remodeling and increased death due to aggravation of heart failure.     

Comparability of Internet and telephone data in a survey on the respiratory health of children

BACKGROUND:

Mixing survey administration modes has generated concern about the comparability of responses between modes.

OBJECTIVE:

To explore the differences in respondent profiles, and responses between Internet and telephone questionnaires in a survey on respiratory diseases.

METHODS:

The data were generated from a mixed Internet and telephone survey of respiratory diseases among children in Montreal (Quebec), in 2006. Comparison of 12 selected questions was performed after standardization for respondent education and income. Stratification of analysis on education and income categories was also performed for the questions with significantly divergent responses.

RESULTS:

Six questions showed significant differences in responses between modes after standardization. The largest differences among the closed-ended questions were observed for highly prevalent symptoms, dry cough during the night (difference of 9% for positive answer [P<0.01]) and symptoms of allergic rhinitis (difference of 7% for positive answer [P<0.01]). A large discrepancy was also found in the multiple choice question and with an open-ended response (ie, free answer). For the three potentially sensitive questions, a desirability bias was probably present in one question on smoking habits (difference of 2.6 % for positive answer [P<0.05]).

CONCLUSION:

The differences observed between Internet and telephone responses to selected questions were not completely explained by socioeconomic disparities among the respondents. In a mixed-mode survey (Internet and telephone), caution should be used when formulating sensitive, complex, open-ended and long-ended questions, and those related to highly prevalent and nonspecific symptoms.     

Oxidative injury as contributory factor for red cells storage lesion during twenty eight days of storage

Background

Storage of red blood cells at 4 °C is associated with deleterious metabolic and biochemical changes, collectively referred to as “storage lesions”. Lipid peroxidation of the red cell membrane leading to lysis contributes to these storage lesions. The aim of the present study was to investigate oxidative injury to red cells during storage for 28 days and its correlation with markers of red cell membrane damage.

Materials and methods

Samples from 30 units of red blood cells stored at 4 °C for 28 days were withdrawn aseptically on day 0, day 14 and day 28 of storage. Markers of membrane damage including plasma haemoglobin, plasma potassium and lactate dehydrogenase (LDH) concentrations and markers of oxidative injury such as malondialdehyde (MDA) levels, haemoglobin oxidation and osmotic fragility were studied in all samples.

Results

Statistically significant (p<0.001) increases in the mean values of plasma haemoglobin, plasma potassium, LDH and markers of oxidative injury such as MDA and haemoglobin oxidation were observed over the storage period of 28 days. Direct correlations of MDA and haemoglobin oxidation with membrane damage, as reflected by plasma haemoglobin concentration, were observed.

Conclusion

Oxidative injury to red blood cells during storage leads to membrane damage and lysis. The role of antioxidants in the prevention of this deleterious effect of storage warrants investigation.     

Sample stability for complete blood cell count using the Sysmex XN haematological analyser

Background

Sample stability is a crucial aspect for the quality of results of a haematology laboratory. This study was conducted to investigate the reliability of haematological testing using Sysmex XN in samples stored for up to 24 h at different temperatures.

Materials and methods

Haematological tests were performed on whole blood samples collected from 16 ostensibly healthy outpatients immediately after collection and 3 h, 6 h or 24 h afterwards, with triple aliquots kept at room temperature, 4 °C or 37 °C.

Results

No meaningful bias was observed after 3 h under different storage conditions, except for red blood cell distribution width (RDW) and platelet count (impedance technique, PLT-I) at 37 °C. After 6 h, meaningful bias was observed for mean corpuscular haemoglobin (MCH) and mean corpuscular volume (MCV) at room temperature, red blood cell (RBC) count, mean corpuscular haemoglobin concentration (MCHC), MCH, MCV and PLT-I at 4 °C, and RBC, RDW, MCHC, MCH and PLT-I at 37 °C. After 24 h, a meaningful bias was observed for MCHC, MCV, platelet count (fluorescent technique, PLT-F) and mean platelet volume (MPV) at room temperature, MCHC, MCV, PLT-I and MPV at 4 °C, and all parameters except RBC count and MPV at 37 °C.

Discussion

Great caution should be observed when analysing results of haematological tests conducted more than 3 h after sample collection.     

Predictive factors for an effective beta-blocker therapy in Chinese patients with congenital long QT syndrome: A multivariate regression analysis

OBJECTIVE:

To investigate the factors that may predict the effectiveness of beta-blocker therapy for congenital long QT syndrome (LQTS) in a Chinese patient population.

METHODS:

Twenty-six LQTS patients were treated with oral propranolol (n=16) or metoprolol tartrate (n=10) for 38 months. Clinical symptoms, heart rate, corrected QT interval (QTc) and left ventricular ejection fraction were assessed before and after the therapy.

RESULTS:

Cardiac events were reduced by more than 50% in 22 patients with beta-blocker therapy. The average number of syncopes/patient and the average frequency of syncopes/patient/year in the responders were reduced from 16.2±5.1 to 1.1±0.9 (P<0.01) and from 4.5+1.2 to 0.7+0.6 (p<0.01), respectively. The QTc was also reduced from 0.56±0.06 s to 0.50±0.03 s. There was no significant difference in the reduction of syncopes and QTc in patients treated with propranolol and metoprolol tartrate. Multivariate regression analysis showed no correlation between the reduction in syncopal attacks and patients’ age, sex, heart rate or left ventricular function (P>0.05). QTc reduction was the only independent predictive factor for syncope control (R=0.81, P<0.001).

CONCLUSIONS:

Oral beta-blockers are an effective therapy for Chinese patients with LQTS. A significant reduction in QTc is highly indicative of treatment success with beta-blockers.     

Association between proximity to major roads and sputum cell counts

BACKGROUND:

Air pollution caused by motor vehicle emissions has been associated with exacerbations of obstructive airway diseases; however, the nature of the resulting bronchitis has not been quantified.

OBJECTIVE:

To examine whether proximity to major roads or highways is associated with an increase in sputum neutrophils or eosinophils, and to evaluate the effect of proximity to roads on spirometry and exacerbations in patients with asthma.

METHODS:

A retrospective study of 485 sputum cell counts from patients attending a tertiary chest clinic in Hamilton, Ontario, identified eosinophilic or neutrophilic bronchitis. Patients’ residences were geocoded to the street network of Hamilton using geographic information system software. Associations among bronchitis, lung function, and proximity to major roads and highways were examined using multinomial logistic and multivariate linear regression analyses adjusted for patient age, smoking status and corticosteroid medications.

RESULTS:

Patients living within 1000 m of highways showed an increased risk of bronchitis (OR 3.8 [95% CI 1.0 to 13.7]; P<0.05), particularly neutrophilic bronchitis (OR 4.7 [95% CI 1.2 to 18.7]; P<0.05) as well as an increased risk of an asthma diagnosis (OR 1.9 [95% CI 1.0 to 3.4]; P<0.05). Patients living within 300 m of a major road were at increased risk for an asthma exacerbation (OR 1.9 [95% CI 1.5 to 15.5]; P<0.01) and lower lung function, particularly in women (P=0.036).

CONCLUSION:

In patients with airway diseases, living close to a highway or major road was associated with neutrophilic bronchitis, an increased risk of asthma diagnosis, asthma exacerbations and lower lung function.     

HIV-related non-Hodgkin��s lymphoma in Calgary

OBJECTIVE:

To determine the incidence of human immunodeficiency virus (HIV) associated non-Hodgkin’s lymphoma (NHL) in a cohort of patients from a distinct geographic region (southern Alberta). The type and location of NHL as well as how it affected the survival of these patients was examined.

PATIENTS AND METHODS:

The Southern Alberta HIV Clinic in Calgary serves all of southern Alberta, which has an estimated population of one million. The clinic has provided primary care for 1086 patients from January 1983 to August 1995. Data were obtained by reviewing the clinic’s database and patients’ charts.

RESULTS:

Over a 12-year period, 39 cases of NHL were diagnosed in a group of 1086 HIV-infected patients. Presentation of NHL was at an extranodal site in all but four cases, with the most common sites being the bowel and central nervous system. The mean CD4 count on presentation with NHL was 143.4±37.4×10⁶/L (range 1 to 1219×10⁶/L). Mean survival was 1.25±0.25 years with a range from 0 (diagnosed on autopsy) to 6.45 years. Patients with a CD4 count of less than 200×10⁶/L and/or diagnosed with an AIDS-defining illness before development of NHL had significantly reduced survival (0.85 years versus 2.48 years, P<0.02 and 0.57 years versus 2.09 years, P<0.001, respectively). Patients who presented with NHL involving either nodes alone or central nervous system had significantly decreased survival (0.28 years and 0.29 years, respectively, P<0.05). Patients with NHL involving the gastrointestinal tract had a longer mean survival than those with NHL elsewhere (P<0.05). All but seven cases received therapy for NHL including chemotherapy, radiotherapy, surgery or combined therapy. Fifteen patients (47% of treated) achieved a complete response that led to improved survival (P<0.01). Patients tolerated surgery, chemotherapy and radiotherapy well and no deaths were due to NHL therapy.

CONCLUSIONS:

These data suggest that development of NHL in HIV is associated with reduced survival, and that survival is predominantly determined by CD4 count and site of involvement at the time of diagnosis of NHL.     

Comparison of Canadian versus American emergency department visits for acute asthma

BACKGROUND:

Acute asthma is a common emergency department (ED) presentation in both Canada and the United States.

OBJECTIVE:

To compare ED asthma management and outcomes between Canada and the United States.

MEHODS:

A prospective cohort study of 69 American and eight Canadian EDs was conducted. Patients aged two to 54 years who presented with acute asthma underwent a structured ED interview and telephone follow-up two weeks later.

RESULTS:

A total of 3031 patients were enrolled. Canadian patients were more likely to be white (89% versus 22%; P<0.001), have health insurance (100% versus 69%; P<0.001) and identify a primary care provider (89% versus 64%; P<0.001) than American patients. In addition, Canadian patients were more likely to be using inhaled corticosteroids (63% versus 44%; P<0.001) and had higher initial peak expiratory flow (61% versus 48%; P<0.001). In the ED, Canadians received fewer beta-agonist (one versus two; P<0.001) and more anticholinergic (two versus one; P<0.001) treatments in the first hour; use of systemic corticosteroids was similar (60% versus 68%; P=0.13). Canadians were less likely to be hospitalized (11% versus 21%; P=0.02). Corticosteroids were prescribed similarly at discharge (60% versus 69%; P=0.13); however, Canadians were discharged more commonly on inhaled corticosteroids (63% versus 11%; P<0.001) and relapses were similar.

CONCLUSIONS:

Canadian patients with acute asthma have fewer barriers to primary care and are more likely to be on preventive medications, both before the ED visit and following discharge. Admissions rates are higher in the United States; however, relapse after discharge is similar between countries. These findings highlight the influences of preventive practices and heath care systems on ED visits for asthma.     

Effects of cigarette smoke, nicotine and cotinine on red blood cell hemolysis and their -SH capacity

BACKGROUND:

Smoking is a leading cause of premature death. Red blood cell (RBC) membrane lipids are rich in polyunsaturated fatty acids; therefore, the effect of oxygen on RBC membranes is more prominent than on other body tissues. The attachment of peroxidants to RBC membranes can result in hemolysis.

OBJECTIVES:

The present study was conducted to assess the sensitivity of RBCs to 2,2′-azo-bis-(2-amidinopropane) dihydrochloride in smokers and nonsmokers. The effect of cigarette smoke, nicotine (1 μg/mL, 1.5 μg/mL and 2.5 μg/mL) and cotinine (1.25 μg/mL, 2.5 μg/mL and 5 μg/mL) on RBC hemolysis was also examined.

RESULTS:

RBC hemolysis in smokers was 21.6% higher than in non-smokers (P<0.05). Cigarette smoke increased 2,2′-azo-bis-(2-amidino-propane) dihydrochloride-induced RBC hemolysis by 281.7%. Nicotine inhibited RBC hemolysis by 36.7% at the highest concentration used, but increased RBC hemolysis at the lower concentrations. Cotinine caused a 13.8% increase in RBC membrane peroxidation at the highest concentration used and its effects were dose-dependent. At their highest concentrations, nicotine and cotinine decreased -SH groups by 50%.

CONCLUSIONS:

The present study confirms the results from previous studies of the oxidative and destructive effects of cigarette smoke, which are detrimental to the health of both active and passive smokers.     

Health care resource use and costs in Crohn's disease before and after infliximab therapy

BACKGROUND:

Infliximab therapy in patients with Crohn’s disease decreases resource use; however, the overall impact on health-related expenditures is unclear, especially beyond one year of study.

METHODS:

A retrospective analysis of economic data one and two years before and after infliximab therapy was performed using patients who served as their own controls. Total health care resource use and direct health care costs were compared for patients with or without fistulae.

RESULTS:

Patients with one (n=66) and two (n=39) years of economic data before and after infliximab treatment had their resource use and direct health care costs estimated. In the year following initiation of infliximab therapy, there were significant decreases in health care use, reflected in total hospital days (495 to 155 [P<0.05]), inpatient colonoscopies (46 to 24 [P<0.05]), outpatient colonoscopies (58 to 33 [P<0.05]) and major surgeries (10 to 2 [P<0.05]). Direct health care costs of inpatient costs for luminal (−$1,747 [P<0.05]) and fistulizing disease (−$2,530 [P<0.05]), major surgeries (−$1240 [P<0.05]) and outpatient colonoscopies (−$184 [P<0.05]) were also significantly reduced before and after infliximab therapy. Total direct health care costs, including the drug cost of infliximab, increased ($21,416 [P<0.05]). In general, the trends in health care costs analyzed over four consecutive years paralleled the two consecutive-year analysis.

CONCLUSIONS:

Infliximab therapy in patients with Crohn’s disease resulted in a significant decrease in both resource use and health care costs, but an increase in total direct health care costs once the cost of infliximab was added.