Pathology: General and Systemic

• Pathology studies disease, covering causes, mechanisms, and effects.
• It links basic science with clinical medicine.
• Molecular pathology is centered on the molecular mechanisms that cause disease.
• Toxicologic pathology studies the effects of toxic substances on living things.
• Toxicologic pathology is key to assessing the safety of drugs, chemicals and environmental toxins.
• Plants are subjects of pathology and agents in pathology.
• Plants can have diseases, caused by pathogens/environmental factors.
• Some plants make toxins, leading to pathological changes in animals and humans.

General Pathology

• Deals with how tissues commonly react to injury, no matter the cause.
• Studies cellular adaptations, inflammation, tissue repair, and neoplasia.

Systemic Pathology

• Focuses on diseases that affect specific organ systems.
• Examples: pathology of the cardiovascular, respiratory, gastrointestinal, and nervous systems.

Molecular Pathology Techniques

• Uses PCR, sequencing, immunohistochemistry to find molecular changes linked to disease.
• These techniques help with diagnosis, prognosis, and predicting how treatment might work.

Applications of Molecular Pathology

• Essential in cancer diagnostics, identifying infectious diseases and personalized medicine.
• Pinpoints specific genetic mutations that cause tumor growth.
• Identifies infectious agents by finding their genetic material.
• Helps customize treatment based on a person's molecular profile.

Mechanisms of Toxicity

• Toxic substances injure cells through direct chemical damage, disrupted processes, and immune reactions.
• Reactive metabolites from toxins bind to cellular macromolecules, resulting in cell damage.

Target Organs in Toxicology

• Some organs are more likely to be injured by toxins because of their metabolic activity/physiological jobs.
• Liver and kidney are common targets since they detoxify/excrete substances.

Pathological Changes Induced by Toxins

• Toxins cause many pathological changes, including necrosis, inflammation, fibrosis, and neoplasia.
• Specific toxins create unique lesions that help identify the responsible agent.

Plants as Subjects of Pathology

• Plants get diseases from pathogens like fungi, bacteria, viruses, and nematodes.
• Plant diseases cause big economic losses in agriculture and forestry.

Plant Defense Mechanisms

• Plants use physical barriers, chemical defenses, and systemic acquired resistance to defend against pathogens.
• Phytoalexins are antimicrobial compounds plants make when attacked by pathogens.

Plants as Agents of Pathology

• Some plants produce toxins causing pathological changes in animals/humans.
• Toxins can impact various organ systems based on their mechanism.

Phytotoxins

• Are poisonous substances made by plants.
• Found in leaves, stems, roots, and seeds.
• Phytotoxin toxicity differs based on compound, dose, and exposure route.

Examples of Toxic Plants

• Poison ivy has urushiol, causing allergic contact dermatitis.
• Oleander has cardiac glycosides, causing cardiac arrhythmias.
• Hemlock has coniine, a neurotoxin causing paralysis and respiratory failure.
• Ragwort has pyrrolizidine alkaloids, causing liver damage.

Mechanisms of Action of Plant Toxins

• Plant toxins trigger enzyme inhibition, cell membrane disruption, and neurotransmission interference.
• Some toxins bind to specific receptors, while others directly harm cellular components.

Diagnosis of Plant Poisoning

• Diagnosing plant poisoning is complex since symptoms are vague, and exposure history might be unknown.
• Identifying the plant is vital when plant poisoning is suspected.
• Lab analysis of plant/biological samples helps confirm diagnoses.

Treatment of Plant Poisoning

• Treatment is based on the toxin, exposure route, and severity of symptoms.
• Supportive care, like managing airways, fluid resuscitation, and treating symptoms, is often needed.
• Sometimes there are specific antidotes available.

Pathology in Plant Disease Diagnosis

• The microscopic study of plant tissues shows disease signs, like fungal hyphae, bacterial colonies, or viral inclusions.
• Molecular techniques like PCR detect pathogens in plant samples.

Plant Pathology and Agriculture

• Secures agricultural crops from disease.
• Disease-resistant crops, specific practices, and chemical controls manage plant diseases.

Challenges in Plant Pathology

• New plant diseases continuously threaten agriculture and forestry.
• Climate change changes the spread and severity of diseases.
• Fungicide resistance is an increasing issue for plant pathogens.

Regulatory Toxicology includes

• Identifying and assessing potential harm from toxic substances.
• Establishing exposure limits to protect human health and the environment.
• Assessing new chemicals/products safety before market release.

Role of Pathology in Drug Development

• Pathologists assess the safety/efficacy of new drugs during trials.
• They analyze tissues/organs for toxicity signs, also evaluating the therapeutic effects.

Histopathology in Toxicologic Pathology

• It involves microscopic tissue examination to find pathological changes caused by toxic substances.
• Essential in toxicologic pathology to assess the severity/nature of toxic injury.

Importance of Understanding Mechanisms in Pathology

• Grasping how diseases/toxins cause pathological changes is key to developing effective diagnostics and treatments.
• Mechanistic studies find potential intervention targets, advancing disease management.

Pathology and Public Health

• Pathology is key in public health by finding/monitoring diseases threatening the population.
• Pathologists help with disease monitoring, investigating outbreaks, and making public health policies.