NEET MDS Synopsis
Infective osteomyelitis
Oral Pathology
Infective osteomyelitis
Tuberculous osteomyelitis
Syphilitic osteomyelitis
Actinomycotic osteomyelitis
Tuberculous osteomyelitis
Non healing sinus tract formation
Age group affected is around 15 – 40 years.
Commonly seen in phalanges and dorsal and lumbar vertebrae.
Usually occurs secondary to tuberculosis of lungs.
Cases have been reported where mandibular lesions were not associated with pulmonary disease.
Another common entrance is through a carious tooth via open pulp.
Usually affects long bones and rare in jaws.
Results when blood borne bacilli lodge in cancellous bone. Usually in ramus , body of mandible. may mimic parotid swelling or submassetric abscess.
Syphilitic osteomyelitis
Difficult to distinguish syphilitic osteomyelitis of the jaws from pyogenic osteomyelitis on clinical & radiographic examination.
Main features are progressive course & failure to improve with usual treatment for pyogenic osteomyelitis.
Massive sequestration may occur resulting in pathologic fracture.
If unchecked, eventually causes perforation of the cortex.
Actinomycotic Osteomyelitis
The organisms thrive in the oral cavity, especially tissues adjacent to mandible.
May enter the bone through a fresh wound, carious tooth or a periodontal pocket at the gingival margin of erupting tooth.
Soft or firm tissue masses on skin, which have purplish, dark red, oily areas with occasional zones of fluctuation.
Spontaneous drainage of serous fluid containing granular material.
Regional lymph nodes occasionally enlarged.
Mimics parotitis / parotid tumors
Bronchitis
General Pathology
Bronchitis
Bronchitis is an obstructive pulmonary disease characterized by inflammation of the bronchi of the lungs
Signs and symptoms
persistent cough that produces sputum
shortness of breath (dyspnea) on exertion
hypercapnia
insufficient oxygenation of the blood hypoxemia leading to cynosis
Severe chronic bronchitis will commonly lead to cor pulmonale and heart failure.
Pathology
an increase in the number of goblet cells with mucus blocking the airway clusters of pigmented alveolar macrophages
the presence of inflammatory cells (e.g. neutrophils) scarring (fibrosis) of the walls of the bronchioles
Diagnosis
decreased intensity of breath sounds (rhonchi) and extended expiration.
a sputum culture has pathogenic microorganisms
a chest x-ray that reveals hyperinflation and increased bronchovascular markings
a pulmonary function test that shows an increase in the lung's residual volume and a decreased vital capacity
Pathophysiology
The initiating event in developing bronchitis appears to be chronic irritation due to inhalation of certain chemicals
earliest clinical feature of bronchitis is increased secretion of mucus by submucousal glands of the trachea and bronchi
Damage caused by irritation of the airways leads to inflammation and infiltration of the lung tissue by neutrophils
The neutrophils release substances that promote mucousal hypersecretion
As bronchitis persists to become chronic bronchitis, a substantial increase in the number of goblet cells in the small airways is seen
The role of infection in the pathogenesis of chronic bronchitis appears to be secondary.
Treatment
Quit smoking, Oxygen therapy, bronchodilator drugs
Prognosis
Pulmonary hypertension, cor pulmonale, and chronic respiratory failure are possible complications of chronic bronchitis
In severe chronic bronchitis is poor
Biological Functions are Extremely Sensitive to pH
PhysiologyBiological Functions are Extremely Sensitive to pH
H+ and OH- ions get special attention because they are very reactive
Substance which donates H+ ions to solution = acid
Substance which donates OH- ions to solution = base
Because we deal with H ions over a very wide range of concentration, physiologists have devised a logarithmic unit, pH, to deal with it
pH = - log [H+]
[H+] is the H ion concentration in moles/liter
Because of the way it is defined a high pH indicates low H ion and a low pH indicates high H ion- it takes a while to get used to the strange definition
Also because of the way it is defined, a change of 1 pH unit means a 10X change in the concentration of H ions
If pH changes by 2 units the H+ concentration changes by 10 X 10 = 100 times
Human blood pH is 7.4
Blood pH above 7.4 = alkalosis
Blood pH below 7.4 = acidosis
Body must get rid of ~15 moles of potential acid/day (mostly CO2)
CO2 reacts with water to form carbonic acid (H2CO3)
Done mostly by lungs & kidney
In neutralization H+ and OH- react to form water
If the pH changes charges on molecules also change, especially charges on proteins
This changes the reactivity of proteins such as enzymes
Large pH changes occur as food passes through the intestines.
FACTORS AFFECTING ENZYME ACTIVITY
Biochemistry
FACTORS AFFECTING ENZYME ACTIVITY
Velocity or rate of enzymatic reaction is assessed by the rate of change in concentration of substrate or product at a given time duration. Various factors which affect the activity of enzymes include:
1. Substrate concentration
2. Enzyme concentration
3. Product concentration
4. Temperature 5. Hydrogen ion concentration (pH)
6. Presence of activators
7. Presence of inhibitor
Effect of substrate Concentration : Reaction velocity of an enzymatic process increases with constant enzyme concentration and increase in substrate concentration.
Effect of enzyme Concentration: As there is optimal substrate concentration, rate of an enzymatic reaction or velocity (V) is directly proportional to the enzyme concentration.
Effect of product concentration In case of a reversible reaction catalyzed by a enzyme, as per the law of mass action the rate of reaction is slowed down with equilibrium. So, rate of reaction is slowed, stopped or even reversed with increase in product concentration
Effect of temperature: Velocity of enzymatic reaction increases with temperature of the medium which they are most efficient and the same is termed as optimum temperature.
Effect of pH: Many enzymes are most efficient in the region of pH 6-7, which is the pH of the cell. Outside this range, enzyme activity drops off very rapidly. Reduction in efficiency caused by changes in the pH is due to changes in the degree of ionization of the substrate and enzyme.
Highly acidic or alkaline conditions bring about a denaturation and subsequent loss of enzymatic activity
Exceptions such as pepsin (with optimum pH 1-2), alkaline phosphatase (with optimum pH 9-10) and acid phosphatase (with optimum pH 4-5)
Presence of activators Presence of certain inorganic ions increases the activity of enzymes. The best examples are chloride ions activated salivary amylase and calcium activated lipases.
Effect of Inhibitors The catalytic enzymatic reaction may be inhibited by substances which prevent the formation of a normal enzyme-substrate complex. The level of inhibition then depends entirely upon the relative concentrations of the true substrate and the inhibitor
The Sphenoid Bone
Anatomy-> This is a wedge-shaped bone (G. sphen, wedge) is located anteriorly to the temporal bones.
-> It is a key bone in the cranium because it articulates with eight bones (frontal, parietal, temporal, occipital, vomer, zygomatic, palatine, and ethmoid).
-> It main parts are the body and the greater and lesser wings, which spread laterally from the body.
-> The superior surface of its body is shaped like a Turkish saddle (L. sella, a saddle); hence its name sella turcica.
-> It forms the hypophyseal fossa which contains the hypophysis cerebri or pituitary gland.
-> The sella turcica is bounded posteriorly by the dorsum sellae, a square plate of bone that projects superiorly and has a posterior clinoid process on each side.
-> Inside the body of the sphenoid bone, there are right and left sphenoid sinuses. The floor of the sella turcica forms the roof of these paranasal sinuses.
-> Studies of the sella turcica and hypophyseal fossa in radiographs or by other imaging techniques are important because they may reflect pathological changes such as a pituitary tumour or an aneurysm of the internal carotid artery. Decalcification of the dorsum sellae is one of the signs of a generalised increase in intracranial pressure.
Common tests in Dental Biostatics and applications
Public Health DentistryCommon tests in dental biostatics and applications
Dental biostatistics involves the application of statistical methods to the
study of dental medicine and oral health. It is used to analyze data, make
inferences, and support decision-making in various dental fields such as
epidemiology, clinical research, public health, and education. Some common tests
and their applications in dental biostatistics include:
1. T-test: This test is used to compare the means of two
independent groups. For example, it can be used to compare the pain levels
experienced by patients who receive two different types of local anesthetics
during dental procedures.
2. ANOVA (Analysis of Variance): This test is used to compare
the means of more than two independent groups. It is often used in dental
studies to evaluate the effectiveness of multiple treatments or to compare the
success rates of different dental materials.
3. Chi-Square Test: This is a non-parametric test used to
assess the relationship between categorical variables. In dental research, it
might be used to determine if there is an association between tooth decay and
socioeconomic status, or between the type of dental restoration and the
frequency of post-operative complications.
4. McNemar's Test: This is a statistical test used to analyze
paired nominal data, such as the change in the presence or absence of a
condition over time. In dentistry, it can be applied to assess the effectiveness
of a treatment by comparing the presence of dental caries in the same patients
before and after the treatment.
5. Kruskal-Wallis Test: This is another non-parametric test for
comparing more than two independent groups. It's useful when the data is not
normally distributed. For instance, it can be used to compare the effectiveness
of three different types of toothpaste in reducing plaque and gingivitis.
6. Mann-Whitney U Test: This test is used to compare the
medians of two independent groups when the data is not normally distributed. It
is often used in dental studies to compare the effectiveness of different
interventions, such as comparing the effectiveness of two mouthwashes in
reducing plaque and gingivitis.
7. Regression Analysis: This statistical method is used to
analyze the relationship between one dependent variable (e.g., tooth loss) and
one or more independent variables (e.g., age, oral hygiene habits, smoking
status). It helps to identify risk factors and predict outcomes.
8. Logistic Regression: This is used to model the relationship
between a binary outcome (e.g., presence or absence of dental caries) and one or
more independent variables. It is commonly used in dental epidemiology to assess
the risk factors for various oral diseases.
9. Cox Proportional Hazards Model: This is a survival analysis
technique used to estimate the time until an event occurs. In dentistry, it
might be used to determine the factors that influence the time until a dental
implant fails.
10. Kaplan-Meier Survival Analysis: This method is used to
estimate the probability of survival over time. It's commonly applied in dental
studies to evaluate the success rates of dental restorations or implants.
11. Fisher's Exact Test: This is used to test the significance
of a relationship between two categorical variables, especially when the sample
size is small. It might be used in a study examining the association between a
specific genetic mutation and the occurrence of oral cancer.
12. Spearman's Rank Correlation Coefficient: This is a
non-parametric measure of the correlation between two continuous or ordinal
variables. It could be used to assess the relationship between the severity of
periodontal disease and the patient's self-reported oral hygiene habits.
13. Cohen's kappa coefficient: This measures the agreement
between two or more raters who are categorizing items into ordered categories.
It is useful in calibration studies among dental professionals to assess the
consistency of their diagnostic or clinical evaluations.
14. Sample Size Calculation: Determining the appropriate sample
size is crucial for ensuring that dental studies are adequately powered to
detect significant differences. This is done using statistical formulas that
take into account the expected effect size, significance level, and power of the
study.
15. Confidence Intervals (CIs): CIs provide a range within
which the true population parameter is likely to lie, given the sample data.
They are commonly reported in dental studies to indicate the precision of the
results, for instance, the estimated difference in treatment efficacy between
two groups.
16. Statistical Significance vs. Clinical Significance: Dental
biostatistics helps differentiate between results that are statistically
significant (unlikely to have occurred by chance) and clinically significant
(large enough to have practical implications for patient care).
17. Meta-Analysis: This technique combines the results of
multiple studies to obtain a more precise estimate of the effectiveness of a
treatment or intervention. It is frequently used in dental research to summarize
the evidence for various treatments and to guide clinical practice.
These tests and applications are essential for designing, conducting, and
interpreting dental research studies. They help ensure that the results are
valid and reliable, and can be applied to improve the quality of oral health
care.
Antibodies used as immunosuppressive drugs and their targets
PharmacologyImmunosuppressive antibodies can be classified mainly into monoclonal and
polyclonal antibodies, targeting specific components of the immune system.
Monoclonal Antibodies:
Basiliximab: Targets the IL-2 receptor on T cells,
inhibiting T-cell activation. It is FDA approved for use in renal
transplantation to prevent acute rejection.
Alemtuzumab: Targets CD52, a protein found on the
surface of mature lymphocytes. It is used for treating chronic
lymphocytic leukemia and as an induction agent in kidney
transplantation.
Rituximab: Targets CD20 on B cells, leading to
B-cell depletion. It is used in various conditions, including
non-Hodgkin lymphoma and rheumatoid arthritis.
Daclizumab: Targets the IL-2 receptor (CD25) and is
used in renal transplantation to prevent acute rejection.
Eculizumab: Targets complement component C5,
inhibiting the complement cascade. It is used in conditions like
paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic
syndrome.
Polyclonal Antibodies:
Rabbit Antithymocyte Globulin (rATG): A polyclonal
antibody that targets multiple T-cell surface markers, leading to T-cell
depletion. It is used as an induction agent in kidney transplantation
and for treating acute rejection.
Equine Antithymocyte Globulin (eATG): Similar to
rATG, it targets T cells and is used in transplantation settings.
Mechanisms of Action:
Depletion of Immune Cells: Many antibodies work by
depleting specific immune cell populations (e.g., T cells or B cells) to
reduce the immune response against transplanted organs or in autoimmune
diseases.
Blocking Activation Signals: Some antibodies block
key receptors involved in T-cell activation, preventing the immune
response from being initiated.
Inhibition of Complement Activation: Antibodies like
eculizumab inhibit the complement system, which can contribute to tissue
damage in antibody-mediated rejection.
Clinical Applications:
Organ Transplantation: Antibodies are commonly used
to prevent rejection in kidney, liver, and heart transplants.
Autoimmune Diseases: They are also used in treating
conditions like rheumatoid arthritis, lupus, and multiple sclerosis.
Potential Side Effects:
Infections: Due to immune suppression, patients are
at increased risk of infections.
Allergic Reactions: Some patients may experience
allergic reactions to antibody therapies.
Infusion Reactions: These can occur during the
administration of monoclonal antibodies, leading to symptoms like fever,
chills, and hypotension.
Meperidine
Pharmacology
Meperidine (Demerol)
Meperidine is a phenylpiperidine and has a number of congeners. It is mostly effective in the CNS and bowel
Produces analgesia, sedation, euphoria and respiratory depression.
Less potent than morphine, 80-100 mg meperidine equals 10 mg morphine.
Shorter duration of action than morphine (2-4 hrs).
Meperidine has greater excitatory activity than does morphine and toxicity may lead to convulsions.
Meperidine appears to have some atropine-like activity.
Does not constrict the pupils to the same extent as morphine.
Does not cause as much constipation as morphine.
Spasmogenic effect on GI and biliary tract smooth muscle is less pronounced than that produced by morphine.
Not an effective antitussive agent.
In contrast to morphine, meperidine increases the force of oxytocin-induced contractions of the uterus.
Often the drug of choice during delivery due to its lack of inhibitory effect on uterine contractions and its relatively short duration of action.
It has serotonergic activity when combined with monoamine oxidase inhibitors, which can produce serotonin toxicity (clonus, hyperreflexia, hyperthermia, and agitation)