NEET MDS Synopsis
Antihypertensives drugs -DIURETICS
Pharmacology
DIURETICS
The basis for the use of diuretics is to promote sodium depletion (and thereby water) which leads to a decrease in extracellular fluid volume.
An important aspect of diuretic therapy is to prevent the development of tolerance to other antihypertensive drugs.
TYPES OF DIURETICS
A. Thiazide Diuretics examples include chlorothiazide
hydrochlorothiazide
a concern with these drugs is the loss of potassium as well as sodium
B. Loop Diuretics (High Ceiling Diuretics) examples include
furosemide (Lasix)
bumetanide
these compounds produce a powerful diuresis and are capable of producing severe derangements of electrolyte balance
C. Potassium Sparing Diuretics examples include
triamterene
amiloride
spironolactone
unlike the other diuretics, these agents do not cause loss of potassium
Mechanism of Action
Initial effects: through reduction of plasma volume and cardiac output.
Long term effect: through decrease in total peripheral vascular resistance.
Advantages
Documented reduction in cardiovascular morbidity and mortality.
Least expensive antihypertensive drugs.
Best drug for treatment of systolic hypertension and for hypertension in theelderly.
Can be combined with all other antihypertensive drugs to produce synergetic effect.
Side Effects
Metabolic effects (uncommon with small doses): hypokalemia,hypomagnesemia, hyponatremia, hyperuricemia, dyslipidemia (increased total
and LDL cholesterol), impaired glucose tolerance, and hypercalcemia (with thiazides).
Postural hypotension.
Impotence in up to 22% of patients.
Considerations
- Moderate salt restriction is the key for effective antihypertensive effect of diuretics and for protection from diuretic - induced hypokalaemia.
- Thiazides are not effective in patients with renal failure (serum creatinine > 2mg /dl) because of reduced glomerular filtration rate.
- Frusemide needs frequent doses ( 2-3 /day ).Thiazides can be given once daily or every other day.
- Potassium supplements should not be routinely combined with thiazide or loop diuretics. They are indicated with hypokalemia (serum potassium < 3.5 mEq/L) especially with concomitant digitalis therapy or left ventricular hypertrophy.
- Nonsteroidal antiinflammatory drugs can antagonize diuretics effectiveness.
Special Indications
Diuretics should be the primary choice in all hypertensives.
They are indicated in:
- Volume dependent forms of hypertension: blacks, elderly, diabetic, renal and obese hypertensives.
- Hypertension complicated with heart failure.
- Resistant hypertension: loop diuretics in large doses are recommended.
- Renal impairment: loop diuretics
Null Hypothesis in Dentistry and applications
Public Health DentistryThe null hypothesis is a fundamental concept in scientific research,
including dentistry, which serves as a starting point for conducting experiments
or studies. It is a statement that assumes there is no relationship, difference,
or effect between the variables being studied. The null hypothesis is often
denoted as H₀.
In dentistry, researchers may formulate a null hypothesis to test the efficacy
of a new treatment, the relationship between oral health and systemic
conditions, or the prevalence of dental diseases. The purpose of the null
hypothesis is to provide a baseline against which the results of the study can
be compared to determine if the observed effects are statistically significant
or not.
Here are some common applications of the null hypothesis in dentistry:
1. Comparing Dental Treatments: Researchers might formulate a
null hypothesis that a new treatment is no more effective than the standard
treatment. For example, "There is no significant difference in the reduction of
dental caries between the use of fluoride toothpaste and a new, alternative
dental gel."
2. Oral Health and Systemic Conditions: A null hypothesis could
be used to test if there is no correlation between oral health and systemic
diseases such as diabetes or cardiovascular disease. For instance, "There is no
significant relationship between periodontal disease and the incidence of
stroke."
3. Dental Materials: Studies might use a null hypothesis to
assess the equivalence of different materials used in dental restorations. For
example, "There is no difference in the longevity of composite resin fillings
compared to amalgam fillings."
4. Dental Procedures: Researchers may compare the effectiveness
of new surgical techniques with traditional ones. The null hypothesis would be
that the new procedure does not result in better patient outcomes. For instance,
"There is no significant difference in post-operative pain between
laser-assisted versus traditional scalpel gum surgery."
5. Epidemiological Studies: In studies examining the prevalence
of dental diseases, the null hypothesis might state that there is no difference
in the rate of cavities between different population groups or regions. For
example, "There is no significant difference in the incidence of dental caries
between children who consume fluoridated water and those who do not."
6. Dental Education: Null hypotheses can be used to evaluate
the impact of new educational methods or interventions on dental student
performance. For instance, "There is no significant improvement in the manual
dexterity skills of dental students using virtual reality training compared to
traditional methods."
7. Oral Hygiene Products: Researchers might hypothesize that a
new toothpaste does not offer any additional benefits over existing products.
The null hypothesis would be that "There is no significant difference in plaque
reduction between the new toothpaste and the market leader."
To test the null hypothesis, researchers conduct statistical analyses on the
data collected from their studies. If the results indicate that the null
hypothesis is likely to be true (usually determined by a p-value greater than
the chosen significance level, such as 0.05), they fail to reject it. However,
if the results suggest that the null hypothesis is unlikely to be true,
researchers reject the null hypothesis and accept the alternative hypothesis,
which posits a relationship, difference, or effect between the variables.
In each of these applications, the null hypothesis is essential for maintaining
a rigorous scientific approach to dental research. It helps to minimize the risk
of confirmation bias and ensures that conclusions are drawn from objective
evidence rather than assumptions or expectations.
Degrees of Mental Disability
PedodonticsDegrees of Mental Disability
Mental disabilities are often classified based on the severity of cognitive
impairment, which can be assessed using various intelligence scales, such as the
Wechsler Intelligence Scale and the Stanford-Binet Scale. Below is a detailed
overview of the degrees of mental disability, including IQ ranges and
communication abilities.
1. Mild Mental Disability
IQ Range: 55-69 (Wechsler Scale) or 52-67 (Stanford-Binet
Scale)
Description:
Individuals in this category may have some difficulty with academic
skills but can often learn basic academic and practical skills.
They typically can communicate well enough for most communication
needs and may function independently with some support.
They may have social skills that allow them to interact with peers
and participate in community activities.
2. Moderate Mental Disability
IQ Range: 40-54 (Wechsler Scale) or 36-51
(Stanford-Binet Scale)
Description:
Individuals with moderate mental disability may have significant
challenges in academic learning and require more support in daily
living.
Communication skills may be limited; they can communicate at a basic
level with others but may struggle with more complex language.
They often need assistance with personal care and may benefit from
structured environments and support.
3. Severe or Profound Mental Disability
IQ Range: 39 and below (Severe) or 35 and below
(Profound)
Description:
Individuals in this category have profound limitations in cognitive
functioning and adaptive behavior.
Communication may be very limited; some may be mute or communicate
only in grunts or very basic sounds.
They typically require extensive support for all aspects of daily
living, including personal care and communication.
Emergency conditions in Dental Clinics p1
Oral Medicine
Emergency conditions in Dental Clinics
Faint - due to Pain or anxiety.
Signs and symptoms
• May be preceded by nausea and closing in of visual fields
• Pallor and sweating
• Heart rate below 60 beats/min (bradycardia) during attack.
T/t
• Give oxygen
• Expect prompt recovery.
• Need to encourage oxygenated blood flow to brain as rapidly as possible
• May need to block vagal activity with atropine and allow heart rate to increase.
If the patient is slow to recover, consider other diagnosis or give 0.3-1 mg atropine i.v.
Hyperventilation- due to Anxiety
Signs and symptoms
• Light-headed
• Tingling in the extremities
• Muscle spasm may lead to characteristic finger position (carpopedal spasm).
Treatment
• Reassure
• Ask patient to re-breathe from cupped hands or reservoir bag of inhalational sedation or general anaesthetic apparatus.
• Reduce anxiety
• Over-breathing has blown off carbon dioxide, resulting in brain blood vessel vasoconstriction. Return carbon dioxide levels in blood to normal.
Postural hypotension- More likely to occur if the patient is taking betablockers,which reduce the capacity to compensate for normal cardiovascular postural changes.
Signs and symptoms
• Light-headed
• Dizzy
• Loss of consciousness on returning to upright or standing position from supine position.
Treatment
Lay the patient flat and give oxygen
Sit the patient up very slowly.
Encourage oxygenated blood flow to brain.
Diabetic emergencies: hypoglycaemia- Patient may have taken medication as normal but not eaten before dental visit.
Signs and symptoms
• Shaking and trembling
• Sweating
• Hunger
• Headache and confusion.
Treatment
• If the patient is conscious, give three sugar lumps or glucose and a little water or glucose oral gel; repeated if necessary in 10 minutes
• If the patient is unconscious, inject 1 mg (1 unit) glucagon by any route (subcutaneous, intramuscular or i.v.).
Return blood glucose level to normal by giving glucose or by converting the patient's own glycogen to glucose by giving glucagon.
Further management
• Transfer the patient to A&E
• Give up to 50 ml 20% glucose i.v. infusion followed by 0.9% saline flush as the glucose damages the vein
• Expect prompt recovery.
Grand mal epileptic seizure- Usually the patient is a known epileptic
• Epilepsy may not be well controlled
• Seizure may be initiated by anxiety or by flickering light tube.
Signs and symptoms
- Sudden loss of consciousness associated with tonic phase in which there is sustained muscular contraction affecting all muscles, including respiratory and mastication
- Breathing may cease and the patient becomes cyanosed
- The tongue may be bitten and incontinence occur After about 30 seconds, a clonic phase supervenes, with violent jerking movements of limbs and trunk.
Treatment• Ensure patient is not at risk of injury during the convulsions but do not attempt to restrain convulsive movements
• Make no attempt to put anything in mouth or between the teeth
• After movements have subsided, place the patient in the recovery position and check airway
• The patient may be confused after the fit: reassure and offer sympathy
• After full recovery, send the patient home unless the seizure was atypical or prolonged or injury occurred.
• Maintain oxygenated blood to brain
• Protect from physical harm
• Administer anticonvulsant.
Further management
Risk of brain damage is increased with length of attack; therefore, treatment should aim to terminate seizure as soon as possible.
If convulsive seizures continue for 15 minutes or longer or are repeated rapidly (status epilepticus):
• transfer to A&E
• remove dentures, insert Guedel or nasopharyngeal airway
• give oxygen
• give 10-20 mg i.v. diazepam (2.5 mg/30 s) as Diazemuls but beware of respiratory depression, or diazepam solution for rectal administration in hospital.
Enzyme Kinetics
Biochemistry
Enzyme Kinetics
Enzymes are protein catalysts that, like all catalysts, speed up the rate of a chemical reaction without being used up in the process. They achieve their effect by temporarily binding to the substrate and, in doing so, lowering the activation energy needed to convert it to a product.
The rate at which an enzyme works is influenced by several factors, e.g.,
the concentration of substrate molecules (the more of them available, the quicker the enzyme molecules collide and bind with them). The concentration of substrate is designated [S] and is expressed in unit of molarity.
the temperature. As the temperature rises, molecular motion - and hence collisions between enzyme and substrate - speed up. But as enzymes are proteins, there is an upper limit beyond which the enzyme becomes denatured and ineffective.
the presence of inhibitors.
competitive inhibitors are molecules that bind to the same site as the substrate - preventing the substrate from binding as they do so - but are not changed by the enzyme.
noncompetitive inhibitors are molecules that bind to some other site on the enzyme reducing its catalytic power.
pH. The conformation of a protein is influenced by pH and as enzyme activity is crucially dependent on its conformation, its activity is likewise affected.
The study of the rate at which an enzyme works is called enzyme kinetics.
Clinical genetics
General Pathology
Clinical genetics (cytogenetics),
This is a method in which inherited chromosomal abnormalities in the germ cells or acquired chromosomal abnormalities in somatic cells are investigated using the techniques of molecular biology.
Composition of Acrylic Resins
Dental Materials
Composition of Acrylic Resins.
· Powder. The powder is composed of a polymethyl methacrylate (PMMA), peroxide initiator, and pigments
· Liquid. The liquid is a monomethyl methacrylate (MMA), hydroquinone inhibitor, cross-linking agents, and chemical accelerators (N, N-dimethyl-p-toluidine)
CONGESTION
General Pathology
CONGESTION
Congestion or hyperaemia means an increase in the content of blood in an organ. It may be :
A. Active - due to increased arterial flow to the organ with dilatation of micro vessels as in
Inflammation.
Increased metabolic activity.
Neurogenic blushing.
B. Passive - due to decreased venous drainage resulting in pooling of blood. There is always an associated element of oedema.