Drugs, Alcohol, and Disease Prevention

• Biology is the youngest of the formalised disciplines of natural science
• Progress in physics and chemistry proceeded much faster than in Biology
• Applications of physics and chemistry in daily life have higher visibility than those of biology
• The twentieth and twenty-first centuries demonstrated the utility of biological knowledge in furthering human welfare
• Discoveries like antibiotics and synthetic plant-derived drugs have impacted healthcare, anaesthetics have changed medical practice and human health
• Health is not simply the absence of disease or physical fitness
• Health includes physical, mental, and social well-being
• Being healthy makes people more efficient at work, increasing productivity and economic prosperity
• Health also expands longevity while reducing infant and maternal mortality
• Balanced diet, personal hygiene, and exercise maintain good health
• Yoga has been practiced for millennia for physical and mental health
• Awareness about diseases, immunization against infectious diseases, proper waste disposal, vector control, and hygiene in food and water are necessary for good health
• Diseases cause affected functioning of organs or systems, showing signs and symptoms
• Diseases can be infectious or non-infectious
• Infectious diseases easily transmit from person to person
• Infectious ailments are common, some are fatal like AIDS
• Non-infectious diseases like cancer are major causes of death
• Substance abuse also affects health negatively

Common Diseases in Humans

• Organisms like bacteria, viruses, fungi, protozoans, and helminths cause disease in humans
• Disease-causing organisms are called pathogens
• Most parasites are pathogens and causes distress to the host by living in or on them
• Pathogens enter the body and interfere with vital activities, causing morphological and functional harm
• Salmonella typhi bacteria cause typhoid fever
• Pathogens enter the small intestine via contaminated food and water and migrate to other organs through blood Symptoms of typhoid:
• a sustained high fever (39° to 40°C), weakness, stomach pain, constipation, headache, and loss of appetite
• Intestinal perforation and death may occur in severe cases
• The Widal test confirms typhoid fever

Case Study: Mary Mallon ("Typhoid Mary")

• Mary Mallon was a cook and typhoid carrier who spread typhoid for years
• Bacteria which result in pneumonia in humans include:
  • Streptococcus pneumoniae
  • Haemophilus influenzae
• Pneumonia infects the alveoli (air-filled sacs) of the lungs, causing them to fill with fluid and making it hard to breathe Symptoms of pneumonia:
  • fever
  • chills
  • cough
  • headache, and in severe cases, bluish lips and fingernails
• Pneumonia transmits when a healthy person inhales infective droplets or aerosols or shares glasses and utensils with an infected person
• Viruses also cause disease in humans, for example, Rhinoviruses
• Rhinoviruses cause the common cold, infecting the nose and respiratory passage but not the lungs
• The common cold symptoms:
  • nasal congestion
  • discharge
  • sore throat
  • hoarseness
  • cough
  • headache
  • tiredness, lasting 3-7 days
• The common cold transmits when a healthy person inhales droplets from coughs or sneezes or touches contaminated objects
• The protozoan Plasmodium causes malaria
• Different Plasmodium species cause different types of malaria:
  • P. vivax
  • P. malaria
  • P. falciparum
• P. falciparum causes malignant malaria, which is very serious and can be fatal
• Plasmodium enters the human body as sporozoites (infectious form) in the saliva of infected female Anopheles mosquitoes
• Parasites multiply in liver cells, then burst to attack red blood cells (RBCs)
• Rupture of RBCs releases a toxic substance, haemozoin, which causes the chills and high fever three to four days
• Plasmodium completes its life cycle in humans and mosquitoes; the female Anopheles mosquito is the vector
• The protozoan parasite Entamoeba histolytica causes amoebiasis (amoebic dysentery)
• Symptoms of amoebiasis:
  • constipation
  • abdominal pain
  • cramps
  • stools with excess mucous and blood clots
• Houseflies transmit the parasite from faeces of infected person to food
• The helminth Ascaris (roundworm) causes ascariasis Symptoms of ascariasis:
  • internal bleeding
  • muscular pain
  • fever
  • anemia
  • blockage of the intestinal passage
• Ascaris eggs excrete in the faeces of affected persons, then contaminates soil, water, plants, etc
• People become infected from Ascariasis through contaminated water, vegetables, fruits, etc
• Filarial worms Wuchereria bancrofti and W. malayi, cause elephantiasis or filariasis where chronic inflammation affects the organs they live in
• Symptoms of filariasis:
  • genital organs can also be affected
  • gross deformities
• Filarial worms transmits by the bite of female mosquito vectors
• Fungi of the genera Microsporum, Trichophyton, and Epidermophyton are responsible for ringworms Symptoms of ringworms:
  • dry, scaly lesions on parts of the body like the skin, nails, and scalp with intense itching
  • heat and moisture help fungi thrive in skin folds
• Ring Worms transmit through soil or using towels, clothes, or combs of infected individuals

Hygiene to avoid infections

• Personal and public hygiene is very important for preventing infectious diseases
• Personal hygiene measures:
  • keeping the body clean
  • drinking clean water
  • eating clean food, vegetables, and fruits
• Public hygiene measures:
  • Proper disposal of waste and excreta, periodic cleaning and disinfection of reservoirs, pools, cesspools, and tanks, and observing hygiene in catering
• Diseases that spread by vectors: -malaria
  • filariasis -dengue -chikungunya
• Effective measures to control diseases include eliminating insect vectors and their breeding places by preventing water stagnation around residential areas, coolers, mosquitos netting, introducing fishes like Gambusia in ponds that feed on mosquito larvae, insecticide sprays in ditches, drainage, etc
• Preventing entry of mosquitoes through wire mesh in doors and Windows is equally important
• Advancements in biological science, such as vaccines have eradicated smallpox
• Biotechnology is making newer and safer vaccines, and antibiotics and other drugs can effectively treat infectious ailment

Immunity Against Infections

• The body can defend itself from most foreign agents
• Immunity is the overall ability of a host to fight disease-causing organisms via the immune system
• Immunity includes innate and acquired immunity
• Innate immunity is a non-specific defense present at the time of birth
• Innate immunity includes:
  • physical barriers like skin and mucus to trap microbes and block their entry
  • physiological barriers such as acid in the stomach, saliva in the mouth, and tears from the eyes to limit/prevent microbial growth
  • cellular barriers using leukocytes (PMNL-neutrophils) and monocytes in the blood, macrophages in tissues destroy microbes
  • cytokine barriers via virus-infected cells secreting interferons to protect non-infected cells from further viral infection

Types of Lymphocytes

• B-lymphocytes produce antibodies to fight pathogens
• T-cells help B cells to make antibodies
• Lymphocyte Immune Response is Cell-Mediated Immunity (CMI)
• Transplantation is the only treatment if organs fail to function properly
• Grafts from just any animal, another primate, or human beings cannot be made
• Tissue and blood group matching is essential before transplant
• Patients take immunosuppressants to deal with transplant rejection
• Body differentiates 'self' and 'nonself'; cell-mediated immune response rejects the graft

Active and Passive Immunity

• Active immunity occurs when antibodies are produced in the host body after exposure to antigens from living or dead microbes
• Active immunity is slow
• Passive immunity occurs when ready-made antibodies are given to protect from foreign agents
• Colostrum and antibodies from the placenta provide passive immunity
• Vaccination and Immunisation exploits the 'memory' of the immune system
• Introducing antigenic proteins of a pathogen (vaccine) causes the body to produces memory B and T cells that quickly recognize and neutralize the pathogen in subsequent exposures
• Tetanus and snakebites may require injecting preformed antibodies, or antitoxin, for rapid immune response (passive immunization)
• Recombinant DNA tech produces antigenic polypeptides in bacteria or yeast for large-scale production of vaccines

Allergies

• allergy is an exaggerated immune response to antigens in the environment, called allergens
• Antibodies produced are of the IgE type
• Common allergens are mites in dust, pollens, and animal dander Symptoms of allergies are:
  • sneezing
  • watery eyes
  • running nose
  • difficulty in breathing

Ways to manage Allergies

• Determining the cause of allergy:
  • exposing/injecting the patient with small doses of allergens and studying reactions
• Drugs like anti-histamine, adrenalin, and steroids reduce allergy symptoms
• Modern lifestyles may increase sensitivity to allergens; metro cities has a rise in allergies and asthma

Auto Immunity

• Memory based acquired immunity identifies foreign organisms from self-cells
• Higher vertebrates can distinguish foreign molecules and organisms
• Unknown reasons can result in the body attacking self-cells, causing damage and autoimmune diseases like rheumatoid arthritis

Immune System

• The immune system recognizes foreign antigens, responds, and remembers them
• The immune system is involved in allergic reactions, autoimmune diseases, and organ transplantation
• Lymphoid organs cause origin/maturation and proliferation of lymphocytes
• Primary lymphoid organs: bone marrow and thymus, where immature lymphocytes differentiate
• After maturation, lymphocytes migrate to secondary lymphoid organs to support lymphocyte interaction with antigens
• The bone marrow is the main lymphoid organ where all blood cells are produced
• Thymus is a lobed organ located near the heart and beneath the breastbone
• The spleen is a large bean-shaped organ that filters the blood by trapping blood-borne micro-organisms and it also has a large reservoir of erythrocytes
• Lymph nodes trap micro-organisms or other antigens
• MALT in the lining of major tracts is 50% of lymphoid tissue

AIDS (Acquired Immuno Deficiency Syndrome)

• AIDS indicates immune system deficiency acquired during an individual's lifetime
• AIDS is not a congenital disease
• AIDS is caused by the Human Immunodeficiency Virus (HIV)
• HIV is a retrovirus that has an envelope enclosing the RNA genome
• HIV transmits:
  • sexual contact
  • contaminated blood and blood products
  • sharing infected needles
  • infected mothers to child through placenta
• After entering, HIV replicates and produces virus particles, acting like a HIV factory, progressively decreasing helper T-lymphocytes
• Patients suffer fever, diarrhea and infection
• The enzyme linked immuno-sorbent assay (ELISA) detects AIDS, and drug is partially effective, prolonging life but cannot prevent death
• Prevent the transmission of AIDS by avoiding/reducing:
  • unsafe sexual contact
  • drug use with recycled needles

Cancer

• Cancer is major cause of death due to oncogenic transformation
• Its development the most intense research fields
• Normal cells show contact inhibition, stopping uncontrolled growth when they contact other cells
• Cancer cells lose this property and divide uncontrollably, forming tumors

Tumors:

• Benign tumors remain confined and cause little damage
• Malignant tumors are cells called neoplastic
• Malignant tumors grow rapidly and damage surrounding normal tissues
• Malignant tumors starve normal cells
• Metastasis facilitates tumors reaching distanced sites
• Carcinogens induce cancerous neoplastic cells
• Ionizing radiations (X-rays and gamma rays) and non-ionizing radiations (UV) cause DNA damage
• Tobacco smoke contains chemical carcinogens, causing lung cancer
• Cancer causing viruses called oncogenic viruses, cause viral oncogenes
• Cellular oncogenes (c-onc) or proto oncogenes activate in certain conditions and can cause oncogenic transformation
• Early cancer detection allows successful treatment
• Cancer detection methods: biopsy, histopathological, blood and bone marrow tests
• Other cancer detection techniques: radiography, CT, MRI and molecular biology

Approaches for Cancer Treatment

• Surgery
• radiation therapy
• immunotherapy
• Radiotherapy kills Tumor cells and surrounds Normal mass with Lethality
• Chemotherapy uses anti-cancer drugs
• Substance called α-interferon activates the patients immune system

Drug and Alcohol Abuse

• Drug and alcohol use, is on the rise, requires awareness
• Affected drugs:
  • opioids
  • cannabinoids
  • coca alkaloids
• Majority are obtained from flowering plants and fungi
• Opioids bind to opioid receptors
• Heroin or "smack" is diacetylmorphine obtained by acetylation of morphine
• Cannabinoids interact with cannabinoid receptors in the brain
• Natural cannabinoids: cannabis sativa that have marijuana, hashish, charas and ganja affecting the cardiovascular impacts
• Coca alkaloid or cocaine interferes with transport of the neurotransmitter dopamine, and increases sense of energy/euphoria
• Atropa belladona and Datura produces hallucinogenic properties

Addiction and Dependence

• Addiction is a physiological attachment to an effect or event
• Tolerance for drugs increases with increased doses
• Addicts develop dependence
• Dependence causes withdrawal syndrome without substance

Effective of Drugs and Alcohol Abuse

• Recklessness, vandalism, and violence
• Over doses may cause harm to systems
• Warning signs of alcohol/drug:
  • drop in academic performance
  • unexplained absence from school
  • fatigue or withdrawal

Prevention and Control

• Avoid undue peer pressure
• Get proper education and good habits
• Get help from parents to avoid the issues
• Look for danger signs to ensure safety

Explore the risks of drug and alcohol use, including intravenous drug use, long-term effects, and impact on fetal development. Understand disease transmission, prevention strategies, and the misuse of drugs by athletes. Learn about DNA vaccines and the immune system.