NEET MDS Synopsis
NUTRITION OF BACTERIA
General Microbiology
NUTRITION OF BACTERIA
Nutrients
Chemoheterotrophs: nutrient source is organic material
Bacteria also requires a source of minerals.
Oxygen
On this basis bacteria have been divided into four groups.
Obligate Anaerobes: These grow only under conditions of high reducing intensity. These bacteria catalase peroxidase, superoxide dismutase and cytochrome systems
Clostridium and Bacteroides are important examples.
Facultalive Anaerobes. These can grow under both aerobic and anaerobic conditions and include members of family enterobacteriaceae and many other bacteria.
Obligatory Aerobes. These cannot grow unless oxygen is present in the medium. Pseudomonas belong to this group.
Microaerophillic. These organisms can grow under conditions with low oxygen tension. Clostridium tetani is an important example.
The strict anaerobes are unable to grow unless Eh is as low as 0.2 volt
Temperature
• On the basis of temperature requirements, three groups of bacteria are recognised.
• Psychrophilic : Growth in the range of —5 to 30°C with an optimum of 10-20
• Mesophillic : bacteria grow best at 20-40°C with a range of 10-45°C.
• Medically important bacteria belong to this group
• Myco. leprae is one such important example and it can grow only at reduced temperature such as footpad of mouse
• Thermophillic organisms prefer high temperature (25-80°C) for growth and yield maximum growth at 50-60°C
pH : Most pathogenic bacteria require a pH of 7.2-7.6 for their own optimal growth.
LIPOPROTIENS
Biochemistry
LIPOPROTIENS
Lipoproteins Consist of a Nonpolar Core & a Single Surface Layer of Amphipathic Lipids
The nonpolar lipid core consists of mainly triacylglycerol and cholesteryl ester and is surrounded by a single surface layer of amphipathic phospholipid and cholesterol molecules .These are oriented so that their polar groups face outward to the aqueous medium. The protein moiety of a lipoprotein is known as an apolipoprotein or apoprotein,constituting nearly 70% of some HDL and as little as 1% of Chylomicons. Some apolipoproteins are integral and cannot be removed, whereas others can be freely transferred to other lipoproteins.
There re five types of lipoproteins, namely chylomicrons, very low density lipoproteins(VLDL) low density lipoproteins (LDL), high density Lipoproteins (HDL) and free fatty acid-albumin complexes.
Wuchereria bancrofti
General Pathology
Wuchereria bancrofti, Brugia malayi (Filariasis)
- the microfilaria of Wuchereria bancrofti or Brugia malayi (nematodes) are transmitted to man by the bite of infected mosquitoes (Anophele, Aedes, Culex).
- microfilaria characteristically circulate in the bloodstream at night and enter into the lymphatics, where they mature and produce an inflammatory reaction resulting in lymphedema (elephantiasis) of the legs, scrotum, etc.
Human tooth development - Permanent
Dental Anatomy
Maxillary (upper) teeth
Permanent teeth
Central
incisor
Lateral
incisor
Canine
First
premolar
Second
premolar
First
molar
Second
molar
Third
molar
Initial calcification
3–4 mo
10–12 mo
4–5 mo
1.5–1.75 yr
2–2.25 yr
at birth
2.5–3 yr
7–9 yr
Crown completed
4–5 yr
4–5 yr
6–7 yr
5–6 yr
6–7 yr
2.5–3 yr
7–8 yr
12–16 yr
Root completed
10 yr
11 yr
13–15 yr
12–13 yr
12–14 yr
9–10 yr
14–16 yr
18–25 yr
Mandibular (lower) teeth
Initial calcification
3–4 mo
3–4 mo
4–5 mo
1.5–2 yr
2.25–2.5 yr
at birth
2.5–3 yr
8–10 yr
Crown completed
4–5 yr
4–5 yr
6–7 yr
5–6 yr
6–7 yr
2.5–3 yr
7–8 yr
12–16 yr
Root completed
9 yr
10 yr
12–14 yr
12–13 yr
13–14 yr
9–10 yr
14–15 yr
18–25 yr
Adrenal Insufficiency
Oral and Maxillofacial SurgeryAdrenal Insufficiency
Adrenal insufficiency is an endocrine disorder characterized
by the inadequate production of certain hormones by the adrenal glands,
primarily cortisol and, in some cases, aldosterone. This condition can
significantly impact various bodily functions and requires careful management.
Types of Adrenal Insufficiency
Primary Adrenal Insufficiency (Addison’s Disease):
Definition: This occurs when the adrenal glands are
damaged, leading to insufficient production of cortisol and often
aldosterone.
Causes: Common causes include autoimmune
destruction of the adrenal glands, infections (such as tuberculosis),
adrenal hemorrhage, and certain genetic disorders.
Secondary Adrenal Insufficiency:
Definition: This occurs when the pituitary gland
fails to produce adequate amounts of Adrenocorticotropic Hormone
(ACTH), which stimulates the adrenal glands to produce
cortisol.
Causes: Causes may include pituitary tumors,
pituitary surgery, or long-term use of corticosteroids that suppress
ACTH production.
Symptoms of Adrenal Insufficiency
Symptoms of adrenal insufficiency typically develop gradually and can vary in
severity. The most common symptoms include:
Chronic, Worsening Fatigue: Persistent tiredness that
does not improve with rest.
Muscle Weakness: Generalized weakness, particularly in
the muscles.
Loss of Appetite: Decreased desire to eat, leading to
weight loss.
Weight Loss: Unintentional weight loss due to decreased
appetite and metabolic changes.
Other symptoms may include:
Nausea and Vomiting: Gastrointestinal disturbances that
can lead to dehydration.
Diarrhea: Frequent loose or watery stools.
Low Blood Pressure: Hypotension that may worsen upon
standing (orthostatic hypotension), causing dizziness or fainting.
Irritability and Depression: Mood changes and
psychological symptoms.
Craving for Salty Foods: Due to loss of sodium and
aldosterone deficiency.
Hypoglycemia: Low blood glucose levels, which can cause
weakness and confusion.
Headache: Frequent or persistent headaches.
Sweating: Increased perspiration without a clear cause.
Menstrual Irregularities: In women, this may manifest
as irregular or absent menstrual periods.
Management and Treatment
Hormone Replacement Therapy: The primary treatment for
adrenal insufficiency involves replacing the deficient hormones. This
typically includes:
Cortisol Replacement: Medications such as
hydrocortisone, prednisone, or dexamethasone are used to replace
cortisol.
Aldosterone Replacement: In cases of primary
adrenal insufficiency, fludrocortisone may be prescribed to replace
aldosterone.
Monitoring and Adjustment: Regular monitoring of
symptoms and hormone levels is essential to adjust medication dosages as
needed.
Preventing Infections: To prevent severe infections,
especially before or after surgery, antibiotics may be prescribed. This is
particularly important for patients with adrenal insufficiency, as they may
have a compromised immune response.
Crisis Management: Patients should be educated about
adrenal crisis, a life-threatening condition that can occur due to severe
stress, illness, or missed medication. Symptoms include severe fatigue,
confusion, and low blood pressure. Immediate medical attention is required,
and patients may need an emergency injection of hydrocortisone.
Immunofluorescence
General MicrobiologyImmunofluorescence
This is precipitation or complement fixation tests. The technique can detect proteins at concentrations of around 1 µg protein per ml body fluid. Major disadvantage with this technique is frequent occurrence of nonspecific fluorescence in the tissues and other material.
The fluorescent dyes commonly used are fluorescein isothocyanate (FITC). These dyes exhibit fluorescence by absorbing UV light between 290 and 495 nm and emitting longer wavelength coloured light of 525 nm which gives shining appearance (fluorescence) to protein labelled with dye. Blue green (apple green) fluorescence is seen with FITC and orange red with rhodamine.
Enzyme Immunoassays
These are commonly called as enzyme linked immunosorbent assays or EL1SA. It is a simple and versatile technique which is as sensitive as radioimmunoassays. It is now the
technique for the detection of antigens, antibodies, hormones, toxins and viruses.
Identification of organisms by immunofluorescence
Type of agent Examples
Bacterial Neisseria gonorrhoeae, H. influenzae ,Strept pyogenes, Treponema pallidum
Viral Herpesvirus, Rabiesvirus, Epstein-Barr virus
Mycotic Candida albicans
Enzymatic activity results in a colour change which can be assessed visibly or quantified in a simple spectrophotometer.
Social Learning Theory
PedodonticsSocial Learning Theory
Antecedent Determinants:
Definition: Antecedent determinants refer to the
factors that precede a behavior and influence its occurrence. This
includes the awareness of the child regarding the context and the events
happening around them.
Application in Pedodontics: In a dental setting, if
a child is aware of what to expect during a dental visit (e.g., through
explanations from the dentist or caregiver), they are more likely to
feel prepared and less anxious. Providing clear information about
procedures can help reduce fear and promote cooperation.
Consequent Determinants:
Definition: Consequent determinants involve the
outcomes that follow a behavior, which can influence future behavior.
This includes the child’s perceptions and expectations about the
consequences of their actions.
Application in Pedodontics: If a child experiences
positive outcomes (e.g., praise, rewards) after cooperating during a
dental procedure, they are more likely to repeat that behavior in the
future. Conversely, if they perceive negative outcomes (e.g., pain or
discomfort), they may develop anxiety or avoidance behaviors.
Modeling:
Definition: Modeling is the process of learning
behaviors through observation of others. Children often imitate the
actions of adults, peers, or even media figures.
Application in Pedodontics: Dental professionals
can use modeling to demonstrate positive behaviors. For example, showing
a child how to sit still in the dental chair or how to brush their teeth
properly can encourage them to imitate those behaviors. Additionally,
having older children or siblings model positive dental experiences can
help younger children feel more comfortable.
Self-Regulation:
Definition: Self-regulation involves the ability to
control one’s own behavior through self-monitoring, judgment, and
evaluation. It includes setting personal goals and assessing one’s own
performance.
Application in Pedodontics: Encouraging children to
set goals for their dental visits (e.g., staying calm during the
appointment) and reflecting on their behavior afterward can foster
self-regulation. Dental professionals can guide children in evaluating
their experiences and recognizing their progress, which can enhance
their sense of agency and responsibility regarding their oral health.
Sedative-Hypnotic and Anxiolytic Drugs
Pharmacology
Sedative-Hypnotic Drugs
Sedative drug is the drug that reduce anxiety (anxiolytic) and produce sedation and referred to as minor tranquillisers.
Hypnotic drug is the drug that induce sleep
Effects: make you sleepy; general CNS depressants
Uses: sedative-hypnotic (insomnia ), anxiolytic (anxiety, panic, obsessive compulsive, phobias), muscle relaxant (spasticity, dystonias), anticonvulsant (absence, status epilepticus, generalized seizures—rapid tolerance develops), others (pre-operative medication and endoscopic procedures, withdrawal from chronic use of ethanol or other CNS depressants)
1- For panic disorder alprazolam is effective.
2- muscle disorder: (reduction of muscle tone and coordination) diazepam is useful in treatment of skeletal muscle spasm e.g. muscle strain and spasticity of degenerative muscle diseases.
3-epilepsy: by increasing seizure threshold.
Clonazepam is useful in chronic treatment of epilepsy while diazepam is drug of choice in status epilepticus.
4-sleep disorder: Three BDZs are effective hypnotic agents; long acting flurazepam, intermediate acting temazepam and short
acting triazolam. They decrease the time taken to get to sleep They increase the total duration of sleep
5-control of alcohol withdrawals symptoms include diazepam, chlordiazepoxide, clorazepate and oxazepam.
6-in anesthesia: as preanesthetic amnesic agent (also in cardioversion) and as a component of balanced anesthesia
Flurazepam significantly reduce both sleep induction time and numbers of awakenings and increase duration of sleep and little rebound insomnia. It may cause daytime sedation.
Temazepam useful in patients who experience frequent awakening, peak sedative effect occur 2-3 hr. after an oral dose.
Triazolam used to induce sleep in recurring insomnia and in individuals have difficulty in going to sleep, tolerance develop within few days and withdrawals result in rebound insomnia therefore the drug used intermittently.
Drugs and their actions
1. Benzodiazepines: enhance the effect of gamma aminobutyric acid (GABA) at GABA receptors on chloride channels. This increases chloride channel conductance in the brain (GABA A A receptors are ion channel receptors).
2. Barbiturates: enhance the effect of GABA on the chloride channel but also increase chloride channel conductance independently of GABA, especially at high doses
3. Zolpidem and zaleplon: work in a similar manner to benzodiazepines but do so only at the benzodiazepine (BZ1) receptor type. (Both BZ1and BZ2 are located on chloride channels.)
4. Chloral hydrate: probably similar action to barbiturates.
5. Buspirone: partial agonist at a specific serotonin receptor (5-HT1A).
6. Other sedatives (e.g., mephenesin, meprobamate, methocarbamol, carisoprodol, cyclobenzaprine):
mechanisms not well-described. Several mechanisms may be involved.
7. Baclofen: stimulates GABA linked to the G protein, Gi , resulting in an increase in K + conductance and a decrease in Ca2+ conductance. (Other drugs mentioned above do not bind to the GABA B receptor.)
8. Antihistamines (e.g., diphenhydramine): block H1 histamine receptors. Doing so in the CNS leads to sedation.
9. Ethyl alcohol: its several actions include a likely effect on the chloride channel.