Indication of spleenectomy.

The following are the indications of spleenectomy:

1. Splenic rupture.
2. Chronic immune thrombocytopenia.
3. Hemolytic anemia
4. Chronic lymphocytic leukaemia
5. Lymphoma
6. Myelofibrosis
7. Tropical spleenomegaly

What is hyperspleenism?

Def: Hyperspleenism is a clinical syndrome that can be seen in any form of spleenomegaly. It is characterized by

1. Enlargement of the spleen.
2. Reduction of at least one cell line in the blood, in the presence of normal bone marrow function.
3. Evidence of increased release of premature cells such as reticulocytes or immature platelets, from the bone marrow into the blood. 

Describe the characteristics of Immunoglobulins.

Immunoglobulins:
These are group of proteins produced by plasma cells and B-lymphocytes that bind to antigen.

IgG:

1. Most common
2. Subdivided in four subclasses IgG1, IgG2, IgG3, IgG4.
3. Produced 2nd to IgM and sustain
4. Heavy chain gamma
5. Present in serum and extracellular fluid
6. Cross placenta
7. Can be broken into a constant Fc fragment and two highly variable Fab fragments.

IgM:

1. Produced first in response to antigen
2. Heavy Chain is meu
3. Consists of 5 subunit
4. Does not cross placenta
5. Present in serum only
6. Complement fixation usual and very different

IgA:

1. Main Immunoglobulins in secretions
2. Does not cross placenta.
3. Heavy chain alpha
4. Compliment fixation in alternative pathway

IgD & IgE:

1. Involved in delayed hypersensitivity reaction

Frozen section: Short note.

Frozen section:
It is a special procedure of tissue biopsy. Tissue is taken during surgery and quickly frozen by cryostat machine and cut by micro-tome and studied after staining.

Advantage:

1. If more tissue is needed to made a diagnosis surgeons can take additional sample avoiding second surgery.
2. It can help to ensure that the entire mass and its surrounding border are removed.

What is dysplasia?

Dysplasia: Dysplasia literally means disordered growth. Dysplasia is principally encountered in epithelia.
Dysplasia is characterized by constellation of changes that include a loss in the uniformity of the individual cells as well as a loss in their architectural orientation.

What is anaplasia?

Anaplasia: Lack of differentiation is called anaplasia. Anaplasia is the hallmark of malignant transformation.

Anaplasia is marked by a number of morphological changes:

1. Pleomorphism: Variation in size and shape.
2. Abnormal nuclear morphology: The nuclei contain abundance of DNA and are extremely dark staining.
3. Mitoses: Malignant tumors usually poses mitoses
4. Loss of polarity: In addition to the cytological abnormalities, the orientation of anaplastic cells is markedly disturbed.
5. Other changes: Formation of giant cells.  

What is differentiation?

Differentiation:

Differentiation refer to the extent to which neoplastic cells resemble comparable to normal cells, both morphologically and functionally.

Write the role of gene in malignant transformation.

Role of gene in malignant transformation:

1. Nonlethal genetic damage lies at the heart of carcinogenesis. Some of the genetic damage may be acquired by the action of environmental agents such as chemicals or virus or may be inherited.
2. A tumor is formed in the clonal expansion of a single precursor cell that has incurred the genetic damage.
3. Four classes of normal regulatory genes - i) The growth promoting protooncogenes, ii) The growth inhibiting tumor suppressor genes, iii) Genes that regulate programmed cell death, iv) And genes involved in DNA repair are principal targets of genetic damage.
4. DNA repair genes affect cell proliferation or survival indirectly by influencing the ability of the organism to repair non-lethal damage in other genes, including proto-oncogenes, tumor suppressor genes and genes that regulate apoptosis
5. Carcinogenesis is a multistep process at both the phenotypic and the genetic levels.

Common Childhood malignancy.

Common childhood malignancy are as follows:

• Neuroblastoma
• Wilms tumor
• Retinoblastoma
• Acute Leukemia
• Rhabdomyosarcoma

Causes or risk factors of childhood malignancy.

Causes (risk factors) of childhood malignancy:

• Race
• Chemotherapeutic agent (Alkylating agents)
• Ionizing radiation in utero
• Down syndrome
• Family history
• EBV
• Immunodeficiency
• Genetic factor

What are the defficiency effects of Vit-D?

Deficiency effects of Vit-D:

• Rickets in children
• Osteomalacia in adults

What are the effects of Vit-A defficiency?

Deficiency effects of Vit-A:

• Night blindness
• Xerophthalmia
• Blindness
• Squamous metaplasia
• Vulnerability to infection, Particularly measles.

What do you mean by stem cell?

Stem cells are undifferentiated biological cells that can differentiate into specialized cells and can divide to produce stem cells.
Two types of stem cell:

1. Embryonic stem cell
2. Adult stem cell

How do cancer cells evade immune system?

Cancer cells can evade immune system by following mechanisms?

1. Failure to produce tumor antigen.
2. Mutations in MHC genes or genes needed for antigen processing.
3. Production of immune-suppressive proteins.

What is immunosurveillance?

Cancer immunosurveillance is a theory where proposed that lymphocytes acts as sentinels in recognizing and eliminating continuously arising nascent transformed cells. Cancer immunosurveillance appears to be an important host protection process that inhibits carcinogenesis and maintains regular cellular homeostasis. It has also been suggested that immunosurveillance primarily functions as a component of a more general process of cancer immunoediting.