Qualitative Ampule and Multitest for Beta-Lactam Residues in Fluid Milk Products: Collaborative Study

A collaborative study was performed on a rapid Bacillus stearothermophilus agar diffusion ampule method to detect low levels of penicillin G in 7 types of fluid milk products. A multitest technique for processing a large number of samples simultaneously was also studied. Slight modifications were made in the original method to establish more uniformity and to eliminate doubtful responses by specifying a confirmation procedure. Twenty samples spiked with penicillin G (0.000 to 0.008 IU/mL) and tetracycline hydrochloride were frozen and sent to 20 laboratories in the ampule test, and 16 laboratories in the multitest. Each analyst was asked to do a screening run and a confirmation run. Results were reported by color reaction and also as positive or negative for β-lactam inhibitors. The concentrations (penicillin G) where percent positive results equal 100 or not significantly less than 100 (α = 0.05) ranged from 0.005 to 0.007 IU/mi in the ampule test and from 0.004 to 0.007 IU/mL in the multitest. Both techniques have been adopted official first action.

The validity of clinical diagnoses of dementia in a group of consecutively autopsied memory clinic patients

BACKGROUND

Epidemiological studies show that up to 10% of individuals aged 65 years and older suffer from dementia, most commonly from dementia of the Alzheimer Type (DAT) (1). Clinicopathological studies are critical to our understanding of this disease and improving the accuracy of clinical diagnoses.

OBJECTIVES

Our objectives were to examine the validity of clinical diagnoses of DAT, to determine the prevalence of different forms of dementia in this sample, and to investigate the relationship between age at death and polymorbidity.

SUBJECTS AND METHOD

Clinical data were available from 221 patients who had been examined at the Basel Memory Clinic between 1986 and 1996. From this population, 34% (75 patients) were autopsied in the Department of Pathology, University Hospital Basel, and neuropathological examinations were additionally performed on 62 (83%) of these patients. Clinical and neuropathological data were retrospectively compared.

RESULTS

67.8% of the neuropathologically examined patients received a definitive diagnosis of AD (Alzheimer's disease), vascular dementia (VaD) or mixed dementia (AD and VaD). AD alone or with other histopathological hallmarks of dementia was the most prevalent neuropathological diagnosis (63%). VaD was deemed the only cause of dementia in only 4.8% of patients. The sensitivity for DAT was 75.9%, the specificity 60.6%. Increasing age was associated with an increasing number of clinical and neuropathological diagnoses.

CONCLUSION

The sensitivity and specificity of the clinical diagnoses of DAT found in our study are similar to previous reports (2-5). Older patients had more etiologies of their dementia than younger patients. This study reaffirms the need for internationally accepted criteria for clinical and neuropathological diagnoses, as well as further clinical-neuropathological investigations to further refine the clinical diagnostic process.