NEET MDS Synopsis
Acid-Peptic disorders
Pharmacology
Acid-Peptic disorders
This group of diseases include peptic ulcer, gastroesophageal reflux and Zollinger-Ellison syndrome.
Pathophysiology of acid-peptic disorders
Peptic ulcer disease is thought to result from an imbalance between cell– destructive effects of hydrochloric acid and pepsin on the one side, and cell-protective effects of mucus and bicarbonate on the other side. Pepsin is a proteolytic enzyme activated in gastric acid (above pH of 4, pepsin is inactive); also it can digest the stomach wall. A bacterium, Helicobacter pylori, is now accepted to be involved in the pathogenesis of peptic ulcer.
In gastroesophageal reflux the acidic contents of the stomach enter into the oesophagus causing a burning sensation in the region of the heart; hence the common name heartburn or other names such as indigestion and dyspepsia.
However, Zollinger-Ellison syndrome is caused by a tumor of gastrin secreting cells of the pancreas characterized by excessive secretion of gastrin that stimulates gastric acid secretion.
These disorders can be treated by the following classes of drugs:
A. Gastric acid neutralizers (antacids)
B. Gastric acid secretion inhibitors (antisecretory drugs)
C. Mucosal protective agents
D. Drugs that exert antimicrobial action against H.pylori
HORMONES
Biochemistry
HORMONES
A hormone is a chemical that acts as a messenger transmitting a signal from one cell to another. When it binds to another cell which is the target of the message, the hormone can alter several aspects of cell function, including cell growth, metabolism, or other function.
Hormones can be classified on three primary ways as following:
1. Autocrine: An autocrine hormone is one that acts on the same cell that released it.
2. Paracrine: A paracrine hormone is one that acts on cells which are nearby relative to the cell which released it. An example of paracrine hormones includes growth factors, which are proteins that stimulate cellular proliferation and differentiation.
3. Endocrine: An endocrine hormone is one that is released into the bloodstream by endocrine glands. The receptor cells are distant from the source. An example of an endocrine hormone is insulin, which is released by the pancreas into the bloodstream where it regulates glucose uptake by liver and muscle cells.
Methods of general anesthesia
Pharmacology
Methods of general anesthesia
CIRCLE SYSTEM
*HIGH-FLOW
FRESH GAS FLOW > 3 l/min.
*LOW-FLOW
FGF ok. 1l/min.
*MINIMAL-FLOW
FGF ok. 0,5 l/min.
Control of processes in the stomach
PhysiologyControl of processes in the stomach:
The stomach, like the rest of the GI tract, receives input from the autonomic nervous system. Positive stimuli come from the parasympathetic division through the vagus nerve. This stimulates normal secretion and motility of the stomach. Control occurs in several phases:
Cephalic phase stimulates secretion in anticipation of eating to prepare the stomach for reception of food. The secretions from cephalic stimulation are watery and contain little enzyme or acid.
Gastric phase of control begins with a direct response to the contact of food in the stomach and is due to stimulation of pressoreceptors in the stomach lining which result in ACh and histamine release triggered by the vagus nerve. The secretion and motility which result begin to churn and liquefy the chyme and build up pressure in the stomach. Chyme surges forward as a result of muscle contraction but is blocked from entering the duodenum by the pyloric sphincter. A phenomenon call retropulsion occurs in which the chyme surges backward only to be pushed forward once again into the pylorus. The presence of this acid chyme in the pylorus causes the release of a hormone called gastrin into the bloodstream. Gastrin has a positive feedback effect on the motility and acid secretion of the stomach. This causes more churning, more pressure, and eventually some chyme enters the duodenum.
Intestinal phase of stomach control occurs. At first this involves more gastrin secretion from duodenal cells which acts as a "go" signal to enhance the stomach action already occurring. But as more acid chyme enters the duodenum the decreasing pH inhibits gastrin secretion and causes the release of negative or "stop" signals from the duodenum.
These take the form of chemicals called enterogastrones which include GIP (gastric inhibitory peptide). GIP inhibits stomach secretion and motility and allows time for the digestive process to proceed in the duodenum before it receives more chyme. The enterogastric reflex also reduces motility and forcefully closes the pyloric sphincter. Eventually as the chyme is removed, the pH increases and gastrin and the "go" signal resumes and the process occurs all over again. This series of "go" and "stop" signals continues until stomach emptying is complete.
Efficiency in Heat Sterilization
Oral and Maxillofacial SurgeryTests for Efficiency in Heat Sterilization – Sterilization Monitoring
Effective sterilization is crucial in healthcare settings to ensure the
safety of patients and the efficacy of medical instruments. Various monitoring
techniques are employed to evaluate the sterilization process, including
mechanical, chemical, and biological parameters. Here’s an overview of these
methods:
1. Mechanical Monitoring
Parameters Assessed:
Cycle Time: The duration of the sterilization
cycle.
Temperature: The temperature reached during the
sterilization process.
Pressure: The pressure maintained within the
sterilizer.
Methods:
Gauges and Displays: Observing the gauges or
digital displays on the sterilizer provides real-time data on the cycle
parameters.
Recording Devices: Some tabletop sterilizers are
equipped with recording devices that print out the cycle parameters for
each load.
Interpretation:
While correct readings indicate that the sterilization conditions
were likely met, incorrect readings can signal potential issues with the
sterilizer, necessitating further investigation.
2. Biological Monitoring
Spore Testing:
Biological Indicators: This involves using spore
strips or vials containing Geobacillus stearothermophilus,
a heat-resistant bacterium.
Frequency: Spore testing should be conducted weekly to
verify the proper functioning of the autoclave.
Interpretation: If the spores are killed after the
sterilization cycle, it confirms that the sterilization process was
effective.
3. Thermometric Testing
Thermocouple:
A thermocouple is used to measure temperature at two locations:
Inside a Test Pack: A thermocouple is placed
within a test pack of towels to assess the temperature reached in
the center of the load.
Chamber Drain: A second thermocouple measures
the temperature at the chamber drain.
Comparison: The readings from both locations are
compared to ensure that the temperature is adequate throughout the load.
4. Chemical Monitoring
Brown’s Test:
This test uses ampoules containing a chemical indicator that changes
color based on temperature.
Color Change: The indicator changes from red
through amber to green at a specific temperature, confirming that the
required temperature was reached.
Autoclave Tape:
Autoclave tape is printed with sensitive ink that changes color when
exposed to specific temperatures.
Bowie-Dick Test: This test is a specific
application of autoclave tape, where two strips are placed on a piece of
square paper and positioned in the center of the test pack.
Test Conditions: When subjected to a temperature
of 134°C for 3.5 minutes, uniform color development
along the strips indicates that steam has penetrated the load
effectively.
Headgear orthodontic appliance
Orthodontics
High-pull headgear consists of a head cap connected to a face-bow. This appliance places a distal and upward force on the maxillary teeth and maxilla. These types of headgear have a more direct effect on the anterior segment of the arch.
Indications: Class II, Division I malocclusion that have an open bite
Cervical-Pull headgear is made up of a neck strap connected to a face bow. This appliance produces a distal and downward force against the maxillary teeth and the maxilla.
A major disadvantage of treatment using cervical headgear is possible extrusion of the maxillary molars Likely results include: opening the bite, first molars will move distally and forward growth of the maxilla will decrease.
Indications: Class II, Division I malocclusions.
Straigh pull headgear is similar to the cervical-pull headgear. However, this appliance places a force in strai ht distal direction form the maxillary molar. Like cervical-pull headgear,
Indications are Class II , Division I malocclusion (when bite opening is undesirable).
Reverse-pull headgear unlike all the other headgears above, the extraoral component is supported by the chin , cheeks, forehead or a combination of these structures.
Indications:
Class III malocclusions (where protraction of the maxilla is desirable).
Pedodontic notes
Pedodontics1. Behavior Modification: Aversive Conditioning (HOME)
Definition: Aversive conditioning is a behavior
modification technique used to manage undesirable behaviors in children,
particularly in a dental setting.
Method: Known as the Hand-Over-Mouth Exercise
(HOME), this technique was introduced by Evangeline Jordan in 1920.
Procedure: The dentist gently places their hand
over the child’s mouth to prevent them from speaking or crying, allowing
for a calm environment to perform dental procedures. This method is
intended to help the child understand that certain behaviors (e.g.,
crying or moving excessively) are not conducive to receiving care.
2. Dental Materials: Crowns
Cheng Crowns:
Composition: These crowns feature a pure resin
facing, which makes them stain-resistant.
Design: Pre-crimped for ease of placement and
adaptation to the tooth structure.
Pedo Pearls:
Description: Aluminum crown forms coated with
tooth-colored epoxy paint.
Durability: Relatively soft, which may affect their
long-term durability compared to other crown materials.
3. Oral Hygiene for Infants
Gum Pad Cleaning:
Timing: Cleaning of gum pads can begin as early as
the first week after birth.
Parental Responsibility: Parents should brush or
clean their baby’s gums and emerging teeth daily until the child is old
enough to manage oral hygiene independently.
4. Indicators of Trauma and Abuse in Children
Frenum Conditions:
Maxillary Labial Frenum: A torn frenum in a young
child may indicate trauma from a slap, fist blow, or forced feeding.
Lingual Frenum: A torn lingual frenum could suggest
sexual abuse or forced feeding.
Signs of Abuse:
Bruising or Petechiae: Presence of bruising or
petechiae on the soft and hard palate may indicate sexual abuse,
particularly in cases of oral penetration.
Infection or Ulceration: If any signs of infection
or ulceration are noted, specimens should be cultured for sexually
transmitted diseases (STDs) such as gonorrhea, syphilis, or venereal
warts.
Neglect Indicators:
A child presenting with extensive untreated dental issues, untreated
infections, or dental pain may be considered a victim of physical
neglect, indicating that parents are not attending to the child’s basic
medical needs.
5. Classical Conditioning
Pavlov’s Contribution: Ivan Petrovich Pavlov was the
first to study classical conditioning, a learning process that occurs
through associations between an environmental stimulus and a naturally
occurring stimulus.
Relevance in Dentistry: Understanding classical
conditioning can help dental professionals develop strategies to create
positive associations with dental visits, thereby reducing anxiety and
fear in children.
Doxycycline
Pharmacology
Doxycycline
Commonly prescribed for infections and to treat acne. treat urinary tract infections, gum disease, and other bacterial infections such as gonorrhea and chlamydia., as a prophylactic treatment for infection by Bacillus anthracis (anthrax). It is also effective against Yersinia pestis and malaria.