- DNA fingerprinting.

- The chemical structure of everyone's DNA is the same.

- The only difference between people (or any animal)

is the order of the base pairs.

- There are so many millions of base pairs in each

person's DNA that every person has a different sequence.

-There are high diversity due to presence of non encoding

areas in the strand either in the genetic area

or outside it see here...

- Using these sequences, every person could

be identified by the sequence of their base pairs.

- Each person has a unique DNA fingerprint,

except monozygous (identical) twins.

- DNA fingerprint is the same for every cell,

tissue, and organ of a person. It cannot be

altered by any known treatment. Consequently,

DNA fingerprinting is rapidly becoming the primary

method for identifying and distinguishing among

individual human beings.

- These patterns do not, however, give an

individual "fingerprint," but they are able to

determine whether two DNA samples are from the

same person, related people, or non-related people.

Scientists use a small number of sequences of DNA

that are known to vary among individuals ,

and analyze those to get a certain probability of a matching.

------------------------------------------------

**Practical Applications of DNA Fingerprinting**

1. Paternity and Maternity :

when a father deny that a certain child is belonging

to him Or tow sets of parents claim on one child.

2. Criminal Identification and Forensics:

- In living (strong evidence of involvement

in assault,rape, disputed paternity)

as DNA isolated from blood,hair, skin cells,

or other genetic evidence left at the scene

of a crime can be compared with the

DNA of a criminal suspect .

- In Dead (DNA survives in bone for many years,

comparison of DNA with family members)

3. Personal Identification .

Enjoy it,see you,

Ibrahim

- DNA strucure and terminology.

Chromosomes are thread-like structures located inside the nucleus of cells. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.

see the picture which illustrate that also show the true genetic content & non genetic areas....

Promoters: are DNA sequences adjacent to the beginning of the genes and control gene activation.

 

Introns are sequences inside the gene although they do not code for protein sequence they are necessary for correct coding.

 

Exons are the regions inside the gene between introns that contain the coding DNA sequences. 

 

Most of the harmful mutations occur in exons and as a consequence change the structure of the coded protein.

 

- Fingerprints.

-friction skin (i.e. palms and soles) have a

impressions due to presence of ridges & grooves .

- These impressions made by dermal papillae in the dermis.

- Finger prints appear in the 4th month intrauterine life.

-Sweat glands open through minute openings on the

summits of the ridges. The sweat contains fat.

- When the skin is applied to a glistening

non-absorbable surface an impression is left behind.


Principles of fingerprint identification :

-fingerprint patterns are unique

(1 in 64 billion chance of 2 prints being identical).

-FBI has over 100 million records, no two of which are alike.

-Fingerprint pattern of an individual remains

unchanged throughout life.

-Reversible atrophy occurs in certain diseases

(coeliac disease, dermatitis).

- Some people have some skin diseases which

prevent normal formation

of fingerprints (may be genetically ).

-Permanent impairment occurs in leprosy and after

exposure to radiation.

-Attempts to mutilate fingerprints are sometimes made.

- If only the epidermis is destroyed there is no

alteration in ridge pattern.

-If dermis is destroyed additional points of

identification are created.

Types:

1-Arches.

2-Loops.

3-Whorls .

4-composite: of more than one type.

-----------------------------

poroscopy

Def: study of the pores of the sweat glands which

present at the ridges of the prints.

Position of the pores requires higher resolution scanner.

---------------

N.B: There are artificial finger prints which

used by criminals for misleading.

see you,

Dr Ibrahim

- New year with success..

In the name of Allah.

Year left & a new year come but we still unchanged ,

this is a big mistake ,

so the intelligent who try to change

themselves to the best as time passes.

The intelligent who throw their bad experiences behind &

start with success.

The intelligent who put the final target

in front of their eyes, but before that

they try to do the stages before the final target

" Rely on Allah then working hard"

Dr Ibrahim

-Plummer-Vinson Syndrome.

Plummer-Vinson Syndrome

- Synonyms:-

Chronic Pharyngo-oesophagitis or Patterson-Brown-Kelly's disease.

-Definition:-

Chronic inflammation of the mucous membrane of the hypopharynx and upper oesophagus.

-Aetiology:-

Unknown, may be iron deficiency anaemia, vitamin deficiency or autoimmune.

- Incidence:-

Commonly in females above 40 years.

-Pathology:-

Atrophic mucosa and submucosal fibrosis leading to formation of webs.

-Clinical picture:-

Symptoms: gradual progressive dysphagia.

Signs:-

• Angular stomatitis with fissured angles of the mouth
• glossitis: (smooth glazed dry tongue)
• glazed atrophic mucosa of the hypopharynx and upper oesophagus with mucosal webs
• splenomegaly
• spooning of the nails (Koilonychia).

-Investigations:-

• Blood picture shows hypochromic microcytic anaemia.
• Gastric secretions: achlorohydria due to atrophic gastritis may be caused by vit. B12 deficiency.
• Hypopharyngoscopy: web formation and stenosis.

- Complications:-

• Submucosal fibrosis leading to web formation and stenosis.
• Pre-cancerous leads to Post-cricoid carcinoma.

-Treatment:-

• Iron and vitamin B complex by injection.
• Repeated endoscopic dilatation.
• Regular follow up to detect early post-cricoid carcinoma.

Return to list of medical syndromes here.