The PIM Unit provides an introduction to the disciplines of Pathology, Immunology and Microbiology. The Immunology component develops concepts of natural and acquired immunity, and students will learn about antigen presentation, activation of lymphocytes and antibody formation.  Microbiological issues addressed in the unit include: the structure and biological activity of bacteria, viruses, parasites and fungi; concepts of classification and identification; mechanisms of pathogenicity; host response to infectious agents; concepts of antimicrobial therapy; and laboratory experience that deals with a number of the above issues. The Pathology component embraces three main themes: cell injury, acute and chronic inflammation, and neoplasia. These topics are addressed through case studies, lectures and laboratory sessions.

In order to guide students through the unit and to provide a framework for learning, we have provided a number of objectives which you should achieve as you work through the cases, lecture material and laboratory sessions.  These are not necessarily all inclusive, and you may develop additional directions of interest as you progress through the unit.  Nonetheless, an acquisition of knowledge that will allow you to address the provided objectives will stand you in good stead for further learning and understanding the disciplines embraced by the unit.

Immunology Objectives

The immune system is important in protection against invading pathogens and as a surveillance mechanism against neoplasms.  It is important to understand how pathogens are recognized and how immune activation occurs and is regulated.  It is also important to understand the complex series of cell and soluble factor interactions that must occur to provide a specific, lasting immune response with memory.  Knowledge of disregulation of the immune response, such as in autoimmunity or immunodeficiencies, and the clinical implications of this disregulation are equally important.

By the end of the unit you should be able to describe or explain:

Inflammation

• Role of clotting cascade and pattern recognition receptor in innate immune activation
• Role of complement in inflammation
  
• Role of inflammatory response in activating innate and specific immunity

Activation and regulation of specific immunity

• Development and maturation of T cells
• Development and maturation of B cells
  
• Antigen presentation and activation of T helper cells
  
• B cell activation and differentiation into plasma cells
  
• Regulation of the immune response, especially the role of cytokines

Host defense against pathogens

• The various roles played by the different classes of antibody in host defense
  
• The role of complement in host defense
  
• The contribution of non-specific effector cells, such as neutrophils and macrophages in host defense
  
• The role of class I MHC in presentation of viral and bacterial antigens
  
• In general, immunological effector mechanisms utilized in defense against extracellular bacteria, intracellular bacteria, intracellular protozoa, extracellular protozoa and viruses

Hypersensitivity

• The immunological basis of allergy
  
• The nature and clinical implications of asthma
  
• The nature of Type II (antibody medicated cytotoxicity) hypersensitivity
  
• The nature and clinical implications of Type III (immune complex disease) hypersensitivity
  
• The nature and clinical implications of Type IV (delayed type) hypersensitivity (DTH) including the role of DTH-like responses in host defense

Immune deficiency

• The basic mechanisms of antibody deficiencies and clinical conditions that result from them
  
• The use and dangers of IgG replacement therapies for antibody deficiencies
  
• The nature and clinical implications of severe combined immune deficiencies

Autoimmunity

• Concepts regarding the basic mechanisms which are thought to lead to the generation of autoimmunity
  
• The nature and clinical presentation of various common autoimmune diseases, such as diabetes, rheumatoid arthritis, multiple sclerosis and autoimmune glomerulonephritis

Microbiology objectives

Bacteria are a major cause of infection in both healthy and immunocompromised persons.  Many of the causative organisms of these infections are part of the normal human microbial flora; others are more exotic.  It is important to understand what these microbes are all about so we can appreciate how they cause infection, how they are transmitted, how we might treat infections and how we might prevent infections.  Similarly, knowledge of fungi and parasites that cause infections is important for the proper treatment and management of patients so infected.  Viruses, a unique life form, represent yet another type of infectious agent which can cause mild to life-threatening diseases.  Knowing how viruses replicate and how some of them may be inhibited by antiviral agents represents fundamental knowledge required for dealing with viral infections.

By the end of the unit you should be able to describe or explain:

Bacteriology

• Bacterial structure and its relationship to bacterial virulence, ability to cause disease, and immunological response
• Concepts of normal flora as both friend and foe
• Virulence factors and mechanisms whereby disease-causing bacteria can be transmitted and establish infection in the host
• Dynamics of bacterial growth
• Bacterial exotoxins and endotoxin, and the role they play in infections
• Genetic exchange among bacteria and its significance in Medical Microbiology

Bacterial pathogenesis

Learn about the following five groups of pathogenic bacteria:

• Anaerobic bacteria
• Staphylococci and streptococci
• Food poisoning and gastrointestinal pathogens
• Opportunistic Gram-negative bacteria that cause disease
• Bacteria that cause sexually transmitted disease

Virology

• Viral structure, classification, replication, and pathogenesis
• Diversity of viruses that cause human disease and the organ tropism of viruses, e.g. the central nervous system, respiratory tract, gastrointestinal tract, etc
• How retroviruses differ from other viruses and how such viruses cause disease in humans
• Modes of transmission of viruses
• Concepts of latency, antigenic modification and immunological response to viruses

Mycology and Parasitology

• The diversity and classification of fungi and parasites
• Principles of culturing and identifying fungi
• Risks of fungal infections for different groups of patients
• Concepts of life cycles of parasites, including types of host and the stages of parasitic growth
• Routes of parasite infection, and preventive strategies

Antimicrobial agents

• The differing strategies for treating bacterial, viral, fungal and parasitic infections
• Types of antibacterial and antiviral agents and, in general, how they work

Laboratory diagnosis

• How the laboratory can assist a physician in diagnosing infectious diseases through culturing, serological and molecular tests, antibiotic sensitivity testing, etc

PATHOLOGY OBJECTIVES

Pathology’s task is to explain the manifestations of the disease process.  How do healthy cells respond to injury?  How much injury can they withstand before dying?  How do cells die?   How the body responds to injury and repairs itself are fundamental questions addressed by Pathology.  The topics of acute and chronic inflammatory response with their associated cellular activities, as viewed by the pathologist, will complement and further develop concepts learned in the Immunology and Microbiology sections of the PIM unit.  Pathological events related to disease of the circulatory system, and the genetic and cellular phenomena related to neoplasia, represent two challenging topics with major relevance for all aspects of medicine.

By the end of the unit you should have an understanding of the topics listed below. More detailed objectives are provided for each case in the student handout for the case, and for each lecture elsewhere in this website.

Cell injury

• Cell injury, necrosis and apoptosis
• Cellular alterations

Thrombosis, embolism and infarction

• Edema, hyperemia, congestion and hemorrhage
• Normal hemostasis
• Thrombosis, embolism and infarction
• Shock

Inflammation

• Acute and chronic inflammation, including granulomatous inflammation

Wound healing and repair

Neoplasia

• Definitions of terms used in neoplasia
• Nomenclature of tumors
• Characteristics of benign and malignant tumors
• Routes of metastasis
• Epidemiology of neoplasia
• The molecular basis of neoplasia
• Carcinogenesis
• Tumor immunity
• The clinical effects of tumors
• Tumor grading and staging
• The laboratory diagnosis of neoplasia

Forensic pathology

· The principles of death investigation and fundamental aspects of forensic pathology e.g. investigation of patterns of injury