Historical data analyses and scientific knowledge suggest complete removal of the abnormal toxicity test as a quality control test

In the early 1900s, the abnormal toxicity test (ATT) was developed as an auxiliary means to ensure safe and consistent antiserum production. Today, the ATT is utilized as a quality control (QC) release test according to pharmacopoeial or other regulatory requirements. The study design has not been changed since around 1940. The evidence of abnormal toxicity testing as a prediction for harmful batches is highly questionable and lacks a scientific rationale. Numerous reviews of historical ATT results have revealed that no reliable conclusions can be drawn from this QC measure. Modern pharmaceutical manufacturers have thorough control of the manufacturing process and comply with good manufacturing practice rules. Contaminants are appropriately controlled by complying with the validated manufacturing processes and strict QC batch release confirming batch-to-batch consistency. Recognizing that product safety, efficacy, and stability can be ensured with strict QC measures, nowadays most regulatory authorities do not require the ATT for most product classes. In line with the replacement, reduction, and refinement (3Rs) initiative, the test requirement has been deleted from approximately 80 monographs of the European Pharmacopoeia and for the majority of product classes in the United States. For these reasons, it is recommended that the ATT should be consistently omitted world-wide and be removed from pharmacopoeias and other regulatory requirements.

Transesophageal echocardiography to detect atrial clots in candidates for percutaneous transseptal mitral balloon valvuloplasty

Left atrial thrombi are common in patients with mitral stenosis. When percutaneous balloon mitral valvuloplasty is performed on such patients, there is a potential risk of thrombus dislodgment and embolization. In this study conventional transthoracic echocardiography and transesophageal echocardiography were performed for percutaneous balloon mitral valvuloplasty on 19 consecutive candidates (6 men, 13 women, 23 to 81 years old). In five patients (26%), transesophageal echocardiography revealed a left atrial thrombus; in only one of these was there a suspicion of left atrial thrombus on transthoracic echocardiography. Balloon mitral valvuloplasty was canceled in four of the five patients. Three underwent mitral valve surgery that confirmed the echocardiographic findings. Transesophageal echocardiography is better than conventional transthoracic echocardiography in detecting left atrial clots in candidates for balloon mitral valvuloplasty. Because of the potential risk of embolization, transesophageal echocardiography is recommended in all candidates for balloon mitral valvuloplasty.

Colonic motility and transit of digesta during hard and soft faeces formation in rabbits

Rabbits produce hard and soft faeces in a circadian rhythm. This study was undertaken in order to examine the motor function of the colon in relation to the formation of these two types of faeces. Colonic motility was measured in unanaesthetized rabbits using strain-gauge transducers and simultaneous radiography. Three types of contractions were found in the rabbit proximal colon: haustral activity, segmental activity, and mass peristalsis. Distinctly different motor patterns were observed during the formation of hard and soft faeces. When hard faeces were produced, the motor activity of the proximal colon was enhanced. It consisted of segmental and haustral activity. The segmental contractions separated the digesta into faecal pellets and forced them slowly aborad, whereas the movements of the haustra carried the liquid contents back towards the caecum. When soft faeces were produced haustral and segmental activity was reduced and transfer of the digesta through the proximal colon was accelerated by mass movements. In contrast to the proximal colon, the motility of the distal colon was enhanced during the formation of soft faeces and decreased during the production of hard faeces. The results support the concept that hard faeces are chiefly produced by a separation of liquids and solids and by a retrograde transfer of liquid digesta rather than by an increased absorption of water.

Physiological significance of the contractions of the rabbit proximal colon

In humans and in carnivores the motor activity of the colon was separated into various types based on records of the intraluminal pressure. However, little is actually known about the physiological significance of the various pressure waves. The aim of the present investigation was to clarify the basic pattern of colonic motility in a herbivorous species. Motility of the proximal colon was studied by strain gauge transducer records combined either with fluoroscopy or by direct visual observation in conscious and anaesthetized rabbits. In the proximal colon three types of contraction were found: (1) high frequency repetitive contractions, (2) low frequency rises of the base line, and (3) monophasic progressive waves. The frequency of the repetitive contractions was 13.8 contractions/min at the oral site and 16.3 contractions/min at the aboral site of the proximal colon. The mean duration of the repetitive contractions was 3.2 +/- 1 s. They coincided with orally migrating (1-2 mm/s) shallow annular constrictions which represented haustral activity. The low frequency rises of the base line (mean duration 13 +/- 47 s) were associated with aborally migrating (7 mm/min) deep annular constrictions representing segmental activity. The monophasic progressive waves represented peristaltic contractions. The mean durations of the monophasic waves 5.5 +/- 1.2 s (period of hard faeces formation), and 9.7 +/- 2.8 s (period of soft faeces formation), the average rates of progression were 3.2 +/- 1.2 cm/s (period of hard faeces production), and 1.3 +/- 0.6 cm/s (period of soft faeces production). The results proved that the colonic motility of rabbits consisted of a complex motor pattern. The present classification was similar but not identical with that described in carnivores and man. Further comparative studies on other mammals are necessary to decide whether the motor activity of the colon is comparable between various species.