Infective Endocarditiis (IE)

IE, in other words means the inflammation of endocardium in response to infection by a microbes. this will cause the formation of vegetations leading to destruction of underlying cardiac tissue. Bacteria is the organism that involved in most cases of IE; so antibiotics is essential in the treatment

according to many epidemological study; people at risk for IE:

• patients with cardiac abnormality (e.g., chronic valvular disease) 
• patients with small ventricular septal defect 
• patient with prosthetic valve 
• intravenous drug abusers

most common causative agent of infective endocarditis:

• alpha-hemolytic streptococci (50-60% of cases); attacking deformed valve 
• staph aureus  attacks both deformed or healthy valve

infective Endocarditis (IE) could be classified into:

1. acute infective endocarditis (AIE)
2. Subacute infective endocarditis (SIE)

Subacute infective endocarditis:
organism involved is alpha-hemolytic streptococci (in contrast to Rheumatic fever which is caused by beta-hemolytics. SIE characterized by vegetation & granulation at the basis of vegetations. most patient will recover properly by antibiotics where in acute infective endocarditis more than 50% will die withing a week.

chemotherapy

chemotherapy its a term for the drug treatment of parasitic infections without causing injury to the human. these chemotherapeutic agents can be classified according to several characteristics for example they can classify into:

1. anitbacterial
2. antifungal 
3. antiviral 
4. antiprotozoal 
5. antiheslmentics 

in turn antibacterial agents can be classified by their action into:

1. bacteriostatics; arrest the bacteria growth without killing them; e.g. all sulfonamides  
2. bactericidals; agents that kills bacteria; e.g., aminoglycosides 

note: some agents (drugs) depending on the dose will be bactericidal or bacteriostatics; if present in high dose they are  bactericidal & on low doe they are bacteriostatics

Factors that determine if the drugs is bactericidal or bacterostatics:

1. the mechanism of action of the drug 
2. the dose (refers here to the concentration of the drug at the site of action) 
3. type of microorganism 

also the chemotherapeutic agent could be classified according to the spectrum of activity into:

1. Narrow Spectrum 
2. Extended Spectrum 
3. broad spectrum 

General Principal of chemotherapy:

1. making the diagnosis; as doctor you must know type of infection, the organism & sensitivity testing
2. removal of barrier; making a way for antibiotics to attack the site of infection (if Abscess present then we must open that abscess, drain the buss & clean it very well; so that antibiotics will works very well) 
3. is chemotherapy is a necessary 
4. select the best drugs; refers to "Specificity of the drug" & this done by knowing the pharmacokientics of the drugs; what its the best the drug in case of pregnancy & lactating or if the patient have allergy to certain agents 
5. the cost 
6. optimum dose & frequency  

Bacteria :Growth & osmatic pressure

Its important to understand how bacteria grow; so that in the condition of disease we can interfere with it. we will consider some requirement of bacteria to grow; several factors influence of bacteria & these includes Temperature, osmotic pressure, pH, Barometric pressure, Gases, Radiation, & Chemicals & presence of neighboring microbes

1. Osmotic pressure
we can define it as the power that drive the solvents across a semi-permeable membrane from low concentration solvent to high concentration.
the concentration of solute play an important role in the growth of bacteria, for example the concentration of salts in pickling inhibits the growth of bacteria; although there are some bacteria that are able to grow (tolerate high concentration of salts) & these called Halophiles 
Based on the concentration of solute we classify into:

1. Hypertonic
2. Hypotonic 

to make it easy to understand difference between hypertonic & hypotonic we will compare bacteria with RBC (Red Blood Cell)
In Hypertonic 

• if we put RBC in hypertonic solution --- RBC will shrink & know RBC will call "crenated red blood cell" 
• if we put Bacteria; here will have a different condition because of the presence of cell wall & the cell will shrink & bacteria will call now "Plasmolysis"

In Hypotonic

• in the case of RBC The Solvent will pass to cell ---- RBC will swell & explode --- this will call hemolysis
•  In case of Bacteria; it will swell but will not explode; because of the cell wall --- this called Palsmoptysis 

 

Chromosome

as we all know, the DNA composed of a sequence of nucleotides that takes the form of helix. in humans the DNA is double stranded with the 2 strands run anti-parallel to each other. normally the DNA will binds to a protein; & these proteins will protect the DNA from degeneration by different enzyme in the surrounding environment.
binding of DNA to protein will result in a structure called nucleoprotein  by looping & looping we finally get a Chromosome; which is a condensed structure. but this condensed structure will relax during cell division; one of the famous figures of the chromosome is the one during a meta-phase (link); in the metaphase each chromosome will be made up of 2 chromatids
during cell division; microtubles will be originated from each pole of the cell & will attach to chromatid; then after splitting; cytokinesis will occurs (cytokinesis is the real division of the cell; because it involves the division of both the cytoplasm & plasma membrane & it will produce 2 daughter cells; so that each one will have a chromosome composed of one chromatid; chromatin strucutre (link) )

Centromeres:
all chromosomes have a constriction where proteins (MT) binding to during metaphase & pull chromatids apart from each other --this constriciton is called centromere; usually the centromere is not located at the center of the chromosome; so it will split the chromosome into 2 pieces have following symbol :

• P: Petit --- the small pieces 
• q: grand --- the longer pieces

centromeres also used to classify the chromosome into:

• metacentric; referring to a central centromere 
• acrocentric; referring to Terminal centromere 
• submetacentric; the Centromere is above or below the center

Telomeres:
periphery of the Chromosome; its the tip of each chromosome; consists of tandem repeats (TTAAGGG)