Pathology

Pathology is the scientific study of disease processes that affect normal anatomy and physiology . Anatomical and physiological changes are pathological changes when they result from an underlying disease process or abnormality. Forensic science is geared towards deducing the nature of the physical and chemical insults that have been inflicted on one or more persons. Sometimes these insults can cause changes in the body. When that occurs, the forensic examination overlaps with pathology. Forensic pathology is the study of the anatomical or physiological changes that are suspicious in their origin.

Pathologists play an increasingly important role in diagnosis, research, and in the development of clinical treatments for disease. A specialized branch of pathology, forensic pathology, offers a vast array of molecular diagnostic techniques (including DNA fingerprint analysis) toward identification of remains, gathering of evidence , and identification of suspects.

Modern pathology labs rely heavily on molecular biology techniques and advances in biotechnology. During the last two decades, there have been tremendous advances in linking changes in cellular or tissue morphology (i.e., gross appearance) with genetic and/or intracellular changes. In many cases, specific molecular tests can definitively identify disease processes and help make a correct diagnosis at an earlier stage in the disease process.

Pathologists attempt to relate observable changes to disease process. Whether the changes are evident morphologically (structurally) or are distinguishable only via sophisticated molecular tests, the goal is to determine the existence and/or etiology of disease (the cause of disease). Once the etiologic agents are identified, the general goal of research is to document and gather evidence of the pathogenesis of disease (i.e., the mechanisms by which etiologic agents cause disease).

On a daily basis, pathologists perform a broad spectrum of tests on clinical samples to determine anatomical and physiological changes associated with a number of disease processes, including the detection of cancerous cells and tumors.

Major branches of pathology include the study of anatomic, cellular, and molecular pathology. Specific clinical studies often focus on transplantation pathology, neuropathology, immunopathology, virology, parasitology , and a number of clinical subspecialties (e.g., pediatric pathology).

Forensic pathology has several specific aims in addition to the aforementioned. The pathological examinations seek to establish what weapon was used, if that is relevant. Also, whether a death was self-inflicted or was a murder is another goal. Finally, the contribution to the death of a pre-existing disease or condition is a goal. For example, a person who is infected with the Human Immunodeficiency Virus often has a compromised immune system that lays them open to the development of other maladies that might otherwise not be fatal (i.e., fungal infections).

see also Amphetamines; Barbiturates; Botulinum toxin; Death, mechanism of; Electrical injury and death; Food poisoning; Hemorrhagic fevers and diseases; Pathogens; Toxicological analysis.

pathology, study of the cause of disease and the modifications in cellular function and changes in cellular structure produced in any cell, organ, or part of the body by disease. The changes in tissue include degeneration, atrophy, hypertrophy, hyperplasia, and inflammation. The microscope is an important factor in detecting tissue changes, especially in the examination of small sections of tissue removed for diagnosis (biopsy); for this reason real progress in pathology was not made until the 19th cent. Other diagnostic techniques for testing body fluids and tissues for abnormal composition or metabolisms are electronmicroscopy, immunocytochemistry, and molecular pathologies.

See E. R. Long, A History of Pathology (1962, repr. 1965); W. A. Anderson and T. M. Scotti, Synopsis of Pathology (8th ed. 1972); L. V. Crowley, Introductory Concepts in Pathology (1972); L. Crowley, Introduction to Human Disease (1989).

Pathologist

Plant pathologists are scientists who work with plant diseases. Trained primarily as biologists, they have expertise both in plant science and microbiology. Whereas in medicine the pathologist is a specialist who analyzes diseased tissues, the plant pathologist is concerned with all aspects of plant disease. All plants are subject to disease, and the work of plant pathologists is central to the management of diseases.

Many plant pathologists may be compared to the general practitioner in medicine, but there are many areas of specialization that may involve the kind of crop or pathogen. Most plant pathologists who work with field crops or vegetables have rather general training in plant pathology, but virologists and nematologists require specialized training because these agents are very different from all other pathogens. Forest pathologists also need unique training, both because the forest is a very different crop and because the common pathogens are different from those that attack agricultural crops. Some plant pathologists are biochemists or molecular biologists who study diseased plants or pathogens. Epidemiologists study the spread of disease in populations and they must be well grounded in mathematics and statistics.

Most jobs taken by plant pathologists require a doctorate degree, but some directors of diagnostic labs have a master's degree. Plant pathologists must be well versed in plant physiology and genetics and must have knowledge of all disease-causing agents. The study of the fungi is particularly important since these are the most numerous and troublesome pathogens of plants. Courses in plant pathology provide background in disease initiation and progress for each kind of pathogen. This knowledge is used when designing programs for management of disease.

Plant pathologists are employed by universities, federal and state governments, and a wide range of industries. All land-grant universities have plant pathologists who are responsible for resident instruction, research, and extension education. Plant pathologists conduct research at state agricultural experiment stations and the U.S. Department of Agriculture, and are employed by federal and state agencies that enforce regulations regarding pesticide use and food safety. Chemical companies employ plant pathologists for production of more effective and safer pesticides, and seed companies use their expertise to produce disease resistant varieties. Many plant pathologists work as consultants or provide service in diagnostic labs.

The complexity of two interacting living systems—the plant and the pathogen—makes plant pathology a very challenging field. An appealing feature of employment as a plant pathologist is the opportunity for work in a wide range of environments. Teaching may occur on the farm as well as in the classroom, and research may be conducted in the field or greenhouse as well as in the laboratory. Disease specimens may be diagnosed in the lab, but disease progress must be evaluated in the field. Plant pathologists have opportunities for research in international centers and for cooperative work with plant pathologists in other countries.

Work by the plant pathologist touches on many important contemporary issues, such as overpopulation, the safety of genetically engineered food, and the effects of pesticides on human health and the environment. But the role played by plant pathologists in the production of abundant, safe food for people of the world is of central importance.

see also Pathogens.

Ira W. Deep

Bibliography

The American Phytopathological Society. [Online] Available at http://www.apsnet.org/.

pa·thol·o·gy / pəˈ[unvoicedth]äləjē/ • n. the science of the causes and effects of diseases, esp. the branch of medicine that deals with the laboratory examination of samples of body tissue for diagnostic or forensic purposes. ∎ Med. pathological features considered collectively; the typical behavior of a disease: the pathology of Huntington's disease. ∎ Med. a pathological condition: the dominant pathology is multiple sclerosis. ∎  mental, social, or linguistic abnormality or malfunction: the city's inability to cope with the pathology of a burgeoning underclass. DERIVATIVES: pa·thol·o·gist / -jist/ n.

pathology Strictly speaking, the scientific study of organic diseases, their causes and symptoms (hence, ‘pathologist’). However, pathological suggests morbidity and abnormality, so the term has also been extended to certain branches of psychiatry and criminology, most obviously in the widespread use of the term ‘psychopath’. In sociology, pathology was once held to be analogous to deviance and social problems or ‘social disease’ (notably in the work of Émile Durkheim), and the concept also blurs into the associated notion of social pathology (see, for example, E. Lemert , Social Pathology, 1951, and B. Wootton , Social Science and Social Pathology, 1959
).

pathology The study of the changes in organs and tissues that are caused by or give rise to disease. This involves the examination of tissue samples, X-ray photographs, or other evidence taken from living patients or from cadavers. Clinical pathology applies these findings to clinical cases, particularly in the development of diagnostic tests and treatments. In experimental pathology, disease processes are studied using experimental animals, cell cultures, or other means.

pathology (pă-thol-ŏji) n. the study of disease processes with the aim of understanding their nature and causes. clinical p. the application of the knowledge of disease processes to the treatment of patients.
—pathologist n.

pathology Study of diseases, their causes and the changes they produce in the cells, tissues, and organs of the body.

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