Infantile seborrhoeic dermatitis and Pityrosporum ovale

Twenty children (mean age 9 weeks) with infantile seborrhoeic dermatitis (ISD) were investigated with cultures for bacteria, Pityrosporum ovale and other fungi, and 20 healthy children served as controls. P. ovale and Staphylococcus aureus were the dominant organisms. P. ovale was cultured in 18 of 20 infants with ISD as compared to 4 of 20 controls. S. aureus was cultured in 14 of 20 infants with ISD as compared to 1 of 20 controls. The role of S. aureus in ISD is not known, but it could be a secondary invader as is supposed in atopic dermatitis (AD). Even if P. ovale may be suspected as the aetiological agent of ISD further studies are needed to clarify the exact role of the organism in ISD.     

Impact of Programmed Sensitivity Safety Factor on Atrial Sensing in Children

The relationship between the pacemaker sensitivity safety factor (PSSF) and atrial under- or oversensing as documented by 24-hour Holter monitoring was examined. Our study comprised 78 transvenous fixed atrial leads implanted between 1983–1995 in 71 children. Overall, 210 Holter reports identified 143 (68%) Holters with normal atrial sensing function, 31 (15%) with undersensing, 32 (15%) with oversensing, and 4 (2%) with both problems. From 161 Holter reports in which the PSSF was available, the incidence of undersensing at a PSSF of 2.0 (range 1.5–2.4) was 25% (14/57). There was a dramatic decline in undersensing when the PSSF was 3 (3%) compared to a FSSF < 3 (21 %) (P < 0.001). A PSSF cut-off point of 2.0 best predicted occurrence of undersensing with a sensitivity of 79% and a specificity of 67%. Other variable were also examined by multiple logistic regression analysis, but only PSSF remained highly associated with undersensing (odds ratio [OR] = 0.6, P = 0.03). In contrast, PSSF did not have a significant role in predicting oversensing, but presence of sick sinus syndrome (OR = 10.5) or unipolar lead (OR = 5.6) were significantly associated with oversensing (P = 0.0001). The majority of undersensing problems can be avoided by routinely allowing for at least a threefold or more programmed sensitivity margin. Other factors may increase the risk of oversensing, regardless of the PSSF.     

Quinidine reduces biliary clearance of digoxin in man

Quinidine is known to reduce the renal clearance of digoxin, but this effect does not completely explain the influence of quinidine on the total clearance of digoxin. We therefore studied the effect of quinidine administration on biliary clearance of digoxin in five patients with atrial fibrillation. Biliary clearance of digoxin under steady state conditions before and during treatment with quinidine was investigated using a duodenal-marker-perfusion technique. Quinidine caused an average 42% (range 21-65%, P less than 0.02) reduction of the measured biliary clearance of digoxin. We conclude that the biliary effect adds to the previously demonstrated inhibitory effect of quinidine on the renal clearance of digoxin and helps to explain the decrease in total clearance of the drug. This is the first demonstration in man of a pharmacokinetic drug interaction at the level of biliary excretion.     

The Biochemical Diagnosis, Localization and Follow up of Phaeochromocytoma: The Role of Plasma and Urinary Catecholamine Measurements

The diagnosis of phaeochromocytoma is dependent on combinedbiochemical and radiological investigation, the biochemicalstudies being performed initially and followed later by bothnon-invasive and invasive radiological techniques. In 23 patientsstudied, a selection of biochemical studies allowed diagnosisand accurate localization of phaeochromocytoma in 16. In somepatients, tumour localization was confirmed by radiographicmethods. Biochemical estimations of catecholamines and/or metabolitesin urine and/or plasma were also performed during and afteroperation, and these measurements allowed monitoring of thecompleteness of tumour excision, and of the possibility of recurrence,in both the short term and long term follow up of patients. ^* Present address: Department of Materia Medica, Stobhill GeneralHospital, Glasgow, G21 3UW.     

Transient Data Stream Dissociation in Computerized Data Acquisition System Masquerading as a Sensing Abnormality

During testing of a CPI model 1715 ICD, an apparent sensing abnormality was noted following shock delivery for VF. Close inspection of the recording prior to the defib-rillation attempt revealed that the surface leads spontaneously lost 848 ms of data while the event marker was unaffected. Computer simulations revealed that an inadequate buffer size for the ampHfied (surface ECC) data was the likely source of data loss. It is important to recognize tbat a discordance between surface leads and event marker may represent an abnormality in tlie data acquisition system and simulate an ICD or lead malfunction.