Baseline abnormal liver function tests are more important than age in the development of isoniazid-induced hepatoxicity for patients receiving preventive therapy for latent tuberculosis infection.

BACKGROUND: One of the cornerstones of Australia's public health programmes to eliminate tuberculosis (TB) is the identification and treatment of latent tuberculosis infection (LTBI). AIMS: The main aim of this study is to determine the demographics, compliance, completion rates and adverse events of patients on preventive therapy (PT) for LTBI at our institution. The secondary aim is to determine the rates of isoniazid (INH) hepatotoxicity and identify any contributory factors. METHODS: The method used was an audit using medical records of 100 consecutive patients (2010-2014) treated with PT for LTBI. RESULTS: Seventy-two patients with confirmed LTBI started 9 months of INH and 22 started 4 months of rifampicin (RIF). The median age was 30 years. Half the patients were born in high TB-prevalence countries. Fifty-six per cent were contacts of index cases with confirmed TB, and 26% were pre-immunosuppression. Seventy-seven per cent completed PT with adequate compliance. Thirty-three per cent on INH and 23% on RIF experienced some liver function test (LFT) abnormality while on treatment. INH was ceased in 3% due to asymptomatic hepatic dysfunction (transaminases >5x upper limit of normal). No patients had permanent liver damage. Significant risk factors for liver dysfunction during PT were risk factors for liver disease (χ(3)(2) = 8.7; P = 0.03) or abnormal pre-therapy LFT (χ(3)(2)= 22.4; P < 0.001). No patients developed active TB. CONCLUSION: The completion rate of 77% and rate of INH-induced hepatic dysfunction of 3% is comparable with the literature. We found no age association with the risk of INH-induced hepatic dysfunction; however, there was a significant and linear association with the degree of liver function abnormality during INH therapy and the presence of abnormal baseline LFT. Routine LFT monitoring allowed early cessation of INH in those with significant but asymptomatic hepatitis who did not meet criteria for ATS/CDC LFT monitoring.

Information from the Internet: attitudes of Australian oncology patients.

BACKGROUND: Patients require accurate information about their illness to make informed decisions. Many sources of information exist, although reliability is variable. Our objective was to investigate information seeking behaviour and attitudes toward health-related information from the Internet in a sample of Australian oncology patients. METHOD: During their outpatient attendance, 109 patients completed a self-administered paper-pen format questionnaire. They were required to have a recent cancer diagnosis (<6 months ago) adequate English and no cognitive impairment. RESULTS: Seventy-four per cent of questionnaires were returned. The majority of patients (78%) wanted as much information about their cancer diagnosis as possible and 90% reported receiving adequate information from their treating team. Despite this, more than half actively searched for additional information, with 77% using the Internet. Patients were trusting of information obtained from the Internet. More than half of information searchers discussed information obtained in their search with a health professional. The majority of patients did not believe that information searching adversely affected the doctor-patient relationship. CONCLUSION: Information searching is common in ambulatory Australian oncology patients, with the Internet being a frequently used resource. To ensure patients find reliable and relevant information and to minimize the risk of harm, health professionals involved in treating oncology patients should provide guidance in finding information sources and assistance in interpreting the information obtained.

Electrophysiologic effects of milrinone in patients with congestive heart failure.

The electrophysiologic effects of milrinone, a new inotropic agent, have not been characterized in humans. Accordingly, 10 patients with class III or IV congestive heart failure underwent hemodynamic and electrophysiologic testing before and during an infusion of milrinone (0.5 micrograms/kg/min). Cardiac index increased from a mean of 1.65 +/- 0.51 to 2.19 +/- 0.68 liters/min/m2 (p less than 0.03) and pulmonary artery capillary pressure decreased from 30 +/- 9 to 22 +/- 9 mm Hg (p less than 0.01), without a significant change in systemic arterial pressure. Holter monitoring was performed for 48 hours at baseline and during infusion of milrinone. Frequency of ventricular premature complexes and ventricular couplets did not change significantly. Frequency of ventricular tachycardia (VT) increased significantly, although no patients would be classified as having a proarrhythmic effect based on a clinical model. PR, QRS, QTc, heart rate, AH, HV, atrial, atrioventricular and ventricular effective and functional refractory periods were not affected. Milrinone decreased 1:1 atrioventricular maximal conduction from 399 +/- 133 to 374 +/- 111 ms (p less than 0.01); ventriculoatrial conduction was not significantly affected. During programmed right ventricular stimulation, 5 patients had inducible VT at baseline (3 sustained, 2 non-sustained), whereas after drug administration, none had it (p less than 0.05). Thus, intravenous milrinone is an effective inotropic drug that also enhances atrioventricular conduction and may decrease the incidence of inducible VT in patients with congestive heart failure.

Electrophysiologic effects of amrinone.

Patients with congestive heart failure (CHF) have a high prevalence of complex ventricular arrhythmias. Accordingly, the electrophysiologic effects of new drugs for the treatment of CHF should be studied to determine whether they are safe in this population of patients. Fifteen patients with New York Heart Association functional classes II to IV CHF underwent hemodynamic and electrophysiologic testing during control conditions, and after 10 to 20 micrograms/kg/min of intravenous amrinone (dosages that increased cardiac output and decreased left ventricular filling pressures). All cardioactive drugs were stopped for at least 5 half-lives before entry into the study. Amrinone decreased the atrial effective refractory period from 256 to 240 ms (p = 0.015) and the AV nodal functional refractory period from 374 to 356 ms (p less than 0.05), and enhanced maximal 1:1 AV nodal conduction from 371 to 334 ms (p = 0.006). Prolonged HV intervals were present in 9 of 15 patients and were not affected by amrinone. Holter monitoring was performed in 10 patients during acute oral administration of amrinone. There were no significant changes in the frequency of ventricular extrasystoles or ventricular tachycardia, although the frequency of ventricular couples tended to increase slightly. Amrinone therefore enhances AV conduction and does not appear to have significant arrhythmogenic potential during acute administration.

Congestive heart failure with normal systolic function.

Although there have been isolated reports of congestive heart failure (CHF) with normal systolic function, the prevalence and characteristics of this condition have not previously been described. Accordingly, 188 patients with CHF undergoing radionuclide ventriculography were prospectively evaluated. Sixty-seven (36%) had a normal ejection fraction (EF) of 0.45 or greater, and 121, an abnormal EF of less than 0.45. Of these, 72 (55 with an abnormal EF [group I] and 17 with a normal EF [group II]) were also reviewed for clinical characteristics. There was no demographic difference between groups, except that systemic hypertension appeared to be a contributing factor in 65% of the patients in group II, compared with 23% of the patients in group I (p less than 0.002). Echocardiographic left atrial emptying index, reflecting left ventricular compliance, was determined in 72 patients and 14 normal subjects. Left atrial emptying index in normal control subjects was 0.93 +/- 0.11 (+/- standard deviation), compared with 0.41 +/- 0.18 in group I and 0.44 +/- 0.19 in group II patients (p less than 0.001 vs control in both groups). Thus, normal systolic function is common among patients with CHF. Diastolic dysfunction, consistent with a noncompliant left ventricle, was found in both CHF groups.

Amrinone: acute electrophysiologic and hemodynamic effects in patients with congestive heart failure.

Amrinone is an effective inotropic agent, but its electrophysiologic effects in humans have not been previously determined. Fifteen patients with congestive heart failure (CHF) New York Heart Association functional class II to IV, underwent an electrophysiologic study after withdrawal of all other cardioactive drugs before and after 10 to 20 micrograms/kg/min of intravenous amrinone (doses that increased cardiac index and decreased pulmonary capillary wedge pressure and systemic vascular resistance, p less than 0.002). Amrinone caused no change in PR, QRS, QTc, AH or HV intervals or maximal corrected sinus node recovery time and had no significant effect on the ventricular effective refractory periods. Amrinone decreased the atrial effective refractory period from 256 +/- 40 to 240 +/- 38 ms (p = 0.015), and the atrioventricular (AV) nodal functional refractory period from 374 +/- 65 to 356 +/- 64 ms (p less than 0.05), and enhanced maximal 1:1 AV nodal conduction from 371 +/- 46 to 334 +/- 47 ms (p = 0.006). Nine patients had baseline HV prolongation; this was not affected by amrinone. The frequency of inducible ventricular tachycardia was not significantly affected by amrinone. Holter recordings (24 to 48 hours) were obtained from 10 patients before and after acute oral amrinone dosing (75 to 150 mg every 8 hours). There was no change in the number of ventricular premature contractions per 24 hours (2,197 +/- 3,305 vs 2,616 +/- 2,436) or number of runs of ventricular tachycardia per 24 hours (10 +/- 12 vs 12 +/- 13); however, the number of ventricular couplets per 24 hours increased from 22 +/- 34 to 52 +/- 55 (p = 0.054).(ABSTRACT TRUNCATED AT 250 WORDS)

Reflection and polarization properties of powder materials.

Directional radiance factors and polarization are presented for pure silicon carbide powder with an average albedo of 0.15 over a size range from 8 micro to 86 micro, pure aluminum oxide powder with average albedo about 0.85 over a size range from 0.1 micro to 86 micro, and for a mixture of one part silicon carbide to six parts aluminum oxide with average albedo of about 0.40 over a size range from 5 micro to 86 micro.