Castleman's disease--difficult diagnosis

A case of Mb. Castleman of the localized plasma cell type is reported. This disease expresses several symptoms from different organ systems and therefore an extensive investigation program is often performed. Diagnosis is possible through consideration of all clinical components at the same time: Refractory anaemia, high and refractory SR, weight loss, B-symptoms, but at the same time a relatively good health. CT-scan-demonstration of a localized tumour is an important clue. Histopathologically, the tumour shows vascular hyperproliferation and plasmacytosis of varying maturation. Immunophenotyping of the plasma cells and immunoblasts usually reveals a polyclonal population. Needle biopsies from several regions may be necessary to detect the polyclonality, because monoclonality is often widespread locally in the tumour. HHV8 is correlated to the multicentric PC-type of Mb. Castleman. However, no HHV8 was found in this case.     

Status spongiosus of rat central nervous system induced by actinomycin D

The effect on central myelin of Actinomycin D, an RNA--and, secondarily, a protein-synthesis inhibitor, has been studied by light and electron microscopy. The intracranial injection of this drug produced an extensive status spongiosus of the white matter in the cerebrum, cerebellum, brain stem and optic nerve within 48 h. The status spongiosus was due to vacuole formation within the myelin sheath and to enlargement of the extracellular space. Three types of vacuoles were observed: (a) the most common varieties formed between the inner tongue and the remainder of the myelin sheath; (b) a second variety formed by enlargement of the periaxonal space with separation of the axon from its myelin sheath, and (c) a less common type of vacuolization was due to splitting of the myelin lamellae at the interperiod line to form large intramyelinic vacuoles. Myelinic vacuoles were preceded by nuclear and cytoplasmic changes in oligodendrocytes, which included nucleolar segregation, disaggregation, and diminution in number of ribosomes. These changes were similar to those previously reported in a variety of cells exposed to Actinomycin D. It is suggested that myelin vacuoles result secondarily from the Actinomycin D inhibitory effect on oligodendroglial RNA--and protein-synthesis, rather than from a direct effect of this drug on the myelin sheath.     

Tumour-initiating activities on mouse skin of dihydrodiols derived from benzo[a]pyrene

Three dihydrodiols that are metabolites of benzo[a]pyrene and benzo[a]-pyrene itself have been tested in a comparative experiment for their activities as initiators of tumours in mouse skin. A single application (25 mug) of 4,5-dihydro-4,5-dihydroxybenzo[a]pyrene, of 7,8-dihydro-7,8-dihydroxybenzo[a]pyrene, of 9,10-dihydro-9,10-dihydroxybenzo[a]pyrene, or of benzo[a]pyrene was made to the shaved dorsal skin of adult female CDI mice; this was followed 2 weeks later by multiple thrice-or twice-weekly applications (1 mug) of 12-O-tetradecanoyl-phorbol-13-acetate as promoting agent. A control group of 30 mice received the promoting agent alone. The experiments were terminated 52 weeks after initiation. At this stage, all the groups contained mice bearing skin papillomas, some of which had progressed to malignancy. Quantitatively the results show that the 7,8-dihydrodiol is almost as active an initiator of mouse skin tumours as benzo[a]pyrene itself; the 4,5- and 9,10-dihydrodiols were significantly less active. The significance of these results is discussed in relation to the hypothesis that diol-epoxides are important in the metabolic activation of polycyclic hydrocarbons like benzo[a]pyrene.     

A study of driver experience and vehicle familiarity in accidents

A separate study was performed as part of a major accident investigation project to (1) test the hypothesis that drivers of vehicles involved in investigated accidents had less driving experience than the general driving population, and (2) test the hypothesis that accident involved drivers were less familiar with their vehicles than the general driving population. A Kolmogorov-Smirnov one-tail test was employed to evaluate the differences in the distributions of driver experience and vehicle familiarity between the “accident sample” and a “control sample.” Results indicated that drivers involved in the investigated accidents had less driving experience in general and had less driving experience with the accident vehicles than drivers in the general population. These effects are discussed briefly and further studies are suggested.     

Blocking of protein pancreatic secretion by maximal secretion infusion in the dog

In conscious chronic gastric and pancreatic fistula dogs (Thomas cannula), secretin was perfused for three hours with a submaximal (GIH, 1.0 C.U./kg.) and a maximal dose (GIH, 8.0 c.u./kg.), according to the following schedule: 1. First hour submaximal stimulus; 2. second hour maximal stimulus; 3. third hour submaximal stimulus. The alkaline and protein components of pancreatic secretion were analyzed in 20-minute sample collections thoughout the three hours. The same protocol was followed in anesthetized dogs subjected to a mind line laparotomy. A biopsy of the pancreatic gland was taken before (control) and at the end of each perfused dose. The secretion showed a significant increase of protein concentration and output when passing from the maximal to the last submaximal secretin perfusion dose. These findings correlated well with the piling up of zymogen and prozymogen granules in the apical zone of the acinar cells during maximal secretin perfusion, with their subsequent discharge into the acinar lumen upon abrupt reversal to the initial secretin submaximal dose. The study confirms that secretin influences pancreatic protein secretion and indicates in addition, that pharmacologic doses of the hormone, have the capacity to block acinar cell zymogen granule release.