[Implementation of the "Digital Pathology in Diagnostics" guideline : Support systems and their functionality]. / Umsetzung des Leitfadens "Digitale Pathologie in der Diagnostik" : Unterstützende Systeme und ihre Funktionalität.

BACKGROUND: The "Digital Pathology in Diagnostics - Assessment of Digital Images" guideline describes the technical and legal framework under which the use of this digital technology is justifiable for the individual pathologist. The focus is on conducting a validation study, defining minimum requirements for the generation and management of whole slide images, and ensuring the functionality and quality of the virtual microscopy solution used. By establishing a special web-based service, supportive services can be provided to assist the pathologist in the introduction of virtual microscopy and quality assurance. AIM: Presentation of the Digitale-Pathologie.de server and description of its services in the context of the guideline. RESULTS AND DISCUSSION: In the context of several scanner contests at the Charité in Berlin, as well as with the introduction of virtual microscopy in practice, many experiences were collected, which will be presented systematically. Essentially, this will provide support for the application of the guideline in practice. The following fields are discussed: implementation of the guideline recommendations, planning and evaluation of the validation study, and ensuring the correct color calibration of the slide scanner being used. Via the Digitale-Pathologie.de server, the possibility for self-monitoring and anonymously benchmarking will be offered. For example, errors in setup can be detected quickly and optimal settings can be identified.

Seeds of hope, seeds of despair: towards a political economy of the seed industry in southern Africa.

The seed industry in Southern Africa has been radically transformed by a policy of liberalisation and privatisation started under structural adjustment. Traditionally under the domain of parastatals, seed research, production and distribution has been criticised for failing to provide modern variety seed to smallholder farmers. However, the private companies which have stepped in to replace seed parastatals in southern Africa have proven no more effective in meeting the demands of smallholders. The Trade Related Intellectual Property Rights (TRIPs) Agreement, concluded in 1994 as part of the Uruguay Rounds of GATT negotiations, as well as certain biotechnological innovations such as Terminator or Traitor technologies, threaten to further undermine local seed production and consumption by destroying the informal seed sector so central to agricultural production in the region. What alternatives exist? The success of Zimbabwe's maize seed network offers some insight. Resting on a unique relationship between government and nationally based producer co-operatives, Zimbabwe's maize programme was able to provide nearly every farmer in the country with hybrid maize suited for local growing conditions.

Use of vitamin B12 in the treatment and prevention of nitroprusside-induced cyanide toxicity.

OBJECTIVE: To review the mechanism of action, safety, and efficacy of hydroxocobalamin in the treatment and prevention of nitroprusside-induced cyanide toxicity. DATA SOURCES: English and foreign-language journal articles and reference texts identified from Index Medicus. Both animal and human studies were included. DATA SYNTHESIS: High-dose or prolonged therapy with nitroprusside in patients with hepatic or renal dysfunction increases the risk for nitroprusside-induced cyanide or thiocyanate toxicity, respectively. Hydroxocobalamin has been shown to significantly reduce RBC and plasma cyanide concentrations in animals and surgical patients without producing clinically important adverse effects or toxic metabolites. Thiosulfate infusions also decrease cyanide toxicity but can cause accumulation of thiocyanate resulting in clinical toxicity. Cyanocobalamin cannot effectively remove cyanide due to poor binding. CONCLUSIONS: Hydroxocobalamin is a safe and effective agent in the prevention and treatment of nitroprusside-induced cyanide toxicity. Prolonged or high-dose infusions of nitroprusside should be minimized in critically ill patients, especially if hepatic and/or renal dysfunction is present.

3-Acetylpyridine-induced degeneration in the dorsal root ganglia: involvement of small diameter neurons and influence of axotomy.

3-Acetylpyridine (3-AP), an analogue of nicotinamide, produces highly selective CNS lesions, the severity of which may be influenced by prior alterations in the metabolic activity of the affected neurons. The present study was undertaken to determine whether prior axotomy modified the response of dorsal root ganglia (DRG) and anterior horn (AH) neurons to 3-AP. A single administration (50 or 80 mg/kg i.p.) of 3-AP to adult rats resulted in degeneration of primarily small-dark DRG neurons by 24 h. The AH neurons were not affected by either dose of 3-AP. Light and electron microscopy of the DRG revealed a spectrum of damage ranging from loss of Nissl substance and cytoplasmic degradation to frank necrosis with neuronophagia. Frequently, injured neurons exhibited perinuclear aggregation of cytoplasmic organelles with dissolution of Nissl substance, clearing of the peripheral cytoplasm, and formation of large peripheral vacuoles. Occasionally, a second pattern of 3-AP injury was observed in which the nuclear chromatin of the neurons was condensed and there was formation of small vacuoles throughout the cytoplasm without peripheral clearing or perinuclear aggregation of cytoplasmic organelles. Axotomy induced typical axon reactions in both large-pale and small-dark DRG neurons. The combination of axotomy followed by 3-AP 4 days later produced morphological features characteristic of both axotomy and 3-AP exposure, but did not appear to alter the incidence of neuronal cell death. The almost exclusive vulnerability of the small dorsal root ganglion neurons to 3-AP neurotoxicity make this model potentially useful for the study of small fibre neuropathies.