Latent Effects Humans

Cutaneous radiation syndrome was the primary cause of death in most of the 32 adult patients who died shortly after the accident. 

Excessive cutaneous fibrosis in 8 survivors who participated in the Chernobyl cleanup was treated successfully with interferon over a period of 36 months. There is general agreement that cleanup workers and populations residing in heavily contaminated areas ( 555,000 Bq Cs/m ) had an increased frequency of thyroid cancers in the period 1986-93, but current epidemiological evidence does not conclusively support an increased incidence of other types of cancers. 

In certain rural portions of Russia receiving Chernobyl contamination on April 28-29, 1986, Cs concentrations in the human body in 1986-87 were positively correlated with consumption of meat and dairy products. Domestic livestock were fed clean feed as much as possible for milk production, and were fed clean feed for 40-120 days before slaughter. Beginning in 1993, however, and persisting to at least 1996, the content of Cs in whole humans correlated positively with the levels of consumption of naturally occurring foodstuffs, such as mushrooms, wild berries, fish, and game. 

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It is important to assess multiple outcomes, since a variety of effects may be correlated if a toxicant has multiple targets or if it has a latent effect. For example, intrauterine growth retardation is a well established correlate for many male reproductive problems, such as testicular cancer (Moller Skakkebaek, 1997), cryptorchidism and hypospadias ( et al., 1999b). The correlation of outcomes is a reflection of the intricate biological interactions of the human organism. 

Reindeer are considered safe for human consumption 6-7 weeks after famphur treatment by intramuscular injection (dermal applications of famphiu seldom penetrate the thick hair coat of reindeer). Treated reindeer had no detectable residues in liver, kidney, and muscle after 3 weeks and none in fat and other tissues after 6-7 weeks. However, treated hinds during the following year had a significantly altered blood-chemistry profile when compared to untreated hinds, suggesting a need for additional research on latent effects of... 

In a number of PSA studies worldwide, THERE is stiU used as an important tool of HRA nowadays. In NRI, THERE has been adapted to help in solution of some specific aspects of plant crew failures (maintenance failures with latent effects) and for detailed task-related probabilistic treatment of more complex scenarios (heavy load drops). An important area of THERE guidance is analysis of dependence among human failures within the same PSA accident sequence. The ASEP clone is currently used in NRI as one of the tools for quantification of manipulation failures in the tasks highly supported with procedures. 

The long latent periods involved in development of cancers make correlation of chemical exposures and disease extremely difficult. This can be countered pardy with tests on naturally short-Hved animals. Tests on bacteria, eg, the Ames test, may permit rapid detection of cancer potential, although there is no direct relationship between the results of bacterial tests and the effects of the tested chemicals on humans (56). 

It is therefore useful to distinguish between active and latent errors or failures. An active human error has an immediate effect in that it either directly causes a hazardous state of the system or is the direct initiator of a chain of events which rapidly leads to the imdesirable state. 

Management policies are the source of many of the preconditions that give rise to systems failures. For example, if no explicit policy exists or if resources are not made available for safety critical areas such as procedures design, the effective presentation of process information, or for ensuring that effective communication systems exist, then human error leading to an accident is, at some stage, inevitable. Such policy failures can be regarded as another form of latent human error, and will be discussed in more detail in Section 2.7. 

Cancer is the major latent harmful effect produced by ionizing radiation and the one that most people exposed to radiation are concerned about. The ability of alpha, beta, and gamma radiation to produce cancer in virtually every tissue and organ in laboratory animals has been well-demonstrated. The development of cancer is not an immediate effect. In humans, radiation-induced leukemia has the shortest latent period at 2 years, while other radiation induced cancers have latent periods >20 years. The mechanism by which cancer is induced in living cells is complex and is a topic of intense study. Exposure to ionizing radiation can produce cancer at any site within the body however, some sites appear to be more common than others, such as the breast, lung, stomach, and thyroid. 

A number of OPC are capable of rendering a delayed neurotoxic effect (DNE). This effect becomes apparent gradually, after a certain latent period (usually 14 to 21 days, sometimes 1 to 5 years after the acute poisoning survived) and is characterized clinically by the development of ataxia, muscular weakness, paresis and paralysis of the extremities. Morphologically, it is characterized by fiber demyelinization of spinal pathways and peripheral nerves. Till present time, near 40,000 cases have been described, when paresis and paralysis developed in human beings as a result of their exposure to OPC (TOCP, mipaphox, chloropyrophos, trichlorfon, etc.) [1],... 

Recently, it has been found that NO donors inhibit HIV-1 replication in acutely infected human peripheral blood mononuclear cells (PBMCs), and have an additive inhibitory effect on HIV-1 replication in combination with 3 -azido-3 -deoxythymisylate (AZT) [139, 140]. S-nitrosothiols (RSNOs) inhibit HIV-1 replication at a step in the viral replicative cycle after reverse transcription, but before or during viral protein expression through a cGMP-independent mechanism. In the latently infected U1 cell line, NO donors and intracellular NO production stimulate HIV-1 reactivation. These studies suggest that NO both inhibits HIV-1 replication in acutely infected cells and stimulates HIV-1 reactivation in chronically infected cells. Thus, NO donors may be useful in the treatment of HIV-1 disease by inhibiting acute infection, or reactivating a latent virus. 

A very important contribution in this socio-technical era is made by Reason (Reason, 1990). He made a distinction between active failures, and latent conditions. The active failures are in general failures made by those at the sharp end of the accident causation (e.g. technical and human failures). Effects are felt almost immediately. Latent conditions are removed in time and space from the sharp end of the accident causation (e.g. organizational and technical failures) creating conditions for active failures to be made. A strict boundary between both concepts cannot be made and in reality can be seen as a sort of sliding transition. Here, the two concepts are separated... 

A technical safety barrier represents technical equipment, whose function it is to arrest the accident/incident evolution so that the next event in the chain will not be realised. The human safety barrier is the suitable people, whose function it is to intervene and arrest the accident/incident evolution so that the next event in the chain will not be realised. The organizational safety barrier is the procedures, rules, guidelines, etc. present, which function to arrest the accident/incident evolution so that the next event in the chain will not be realised. In this thesis the latent conditions and precursors in an unfolding situation are considered to have three possible effects on the safety barriers negative, positive or none at all. 

Once both latent conditions and precursors are identified in the company s control process and operational process, the effects on the company s safety barriers can be retrieved. Therefore, the safety barriers present around the transformation process will be identified, i.e. technical, human, and organizational safety barriers. Subsequently, the identified types of latent conditions are used to check if they affect the identified safety barriers either positively, negatively, or not at all (as discussed in the previous Chapter). How safety barriers are affected is illustrated by the example of the re-... 

Grainger (G20) reports that Lp(a) promotes proliferation of human smooth muscle cells by inhibition of the activation of plasminogen and activating effect of plasmin on latent transforming growth factor-(3. 

Ideally, the most effective prevention of HIV infection would be a vaccine that blocks virus infection in individuals. Indeed, effective vaccines have been developed against most human viruses that cause serious diseases. While several different possible vaccines against HIV are under development, there are some theoretical reasons why it may be difficult to develop an effective one. First, HIV has the unique ability to evade the immune system in an infected individual. Briefly, this results from (1) the high mutation rate of the virus, particularly in the env gene (2) the ability of the virus to establish a latent state in some cells and (3) the ability of the virus to spread by cell-to-cell contact. The object of the vaccine is to raise a protective immune response to the infectious agent. Since HIV evades the immune system so efficiently, it may be difficult for a vaccine to prevent HIV infection in an individual, even if it can induce production of neutralizing antibodies or cell-mediated immunity. 

Korin YD, Brooks DG, Brown S, Korotzer A, Zack JA (2002) Effects of prostratin on T-cell activation and human iimnunodeficiency virus latency. J Virol 76 8118—8123 Kulkosky J, Culnan DM, Roman J, Domadula G, Schnell M, Boyd MR, Pomerantz RJ (2001) Prostratin activation of latent HlV-l expression suggests a potential inductive adjuvant therapy for HAART. Blood 98 3006-3015... 

Scripture-Adams DD, Brooks DG, Korin YD, Zack JA (2002) Interleukin-7 induces expression of latent human immunodeficiency virus type 1 with minimal effects on T-cell phenotype. I Virol 76 13077-13082... 

Contact of solutions of ethylene oxide with the skin of human volunteers caused characteristic burns after a latent period of 1-5 hours, effects were edema and erythema and progression to vesiculation, with a tendency to coalescence into blebs, and desquamation. Complete healing without treatment usually occurred within 21 days with, in some cases, residual brown pigmentation. Application of the liquid to the skin caused frostbite three of the eight volunteers were said to have become sensitized to ethylene oxide solutions. The undiluted liquid or solutions may cause severe eye irritation or damage. 

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