Dear Rebecca,

you could also use Bouin´s solution. Fix it for 12 hours, wash it several times in 70% ethanol and then you can store it in 70% ethanol for a considerable time.

Goog luck, Fred

Dear Rebecca M Delles 

You have to keep your specimens as a wax. the protocol is:

Paraffin Section Method and Technique

Fix tissues with 10% formalin or other fixatives for 24-48 hours at room temperature. Make sure you have enough fixative to cover tissues. Fixative volume should be 5-10 times of tissue volume.

Trim fixed tissues into appropriate size and shape and place in embedding cassettes.

Process for paraffin embedding schedule as follow (total 16 hours):

70% Ethanol, two changes, 1 hour each

80% Ethanol, one change, 1 hour

95% Ethanol, one change, 1 hour

100% Ethanol, three changes, 1.5 hour each

Xylene or xylene substitute (i.e. Clear Rite 3), three changes, 1.5 hour each

Paraffin wax (58-60 ºC), two changes, 2 hours each

Embedding tissues into paraffin blocks.

Trim paraffin blocks as necessary and cut at 3-10 um (5 um is commonly used).

Place paraffin ribbon in water bath at about 40-45 ºC.

Mount sections onto slides.

Allow sections to air dry for 30 minutes and then bake in 45-50 ºC oven overnight. NEVER allow baking temperature go higher than 50 ºC for sections thicker than 25um.  Otherwise sections may crack, especially 25-50 um thick sections, and result in sections falling off slides during staining.

The deparaffinize sections in 2-3 changes of xylene, 10 minutes each. Use three changes of xylene for sections thicker than 25 um.

Hydrate in 2 changes of 100% ethanol for 3 minutes each, 95% and 80% ethanol for 1 minute each. Then rinse in distilled water.

http://www.ihcworld.com/_protocols/histology/paraffin_section.htm

70% ethanol should do it fine.

even you can keep it in NBF 10% for long term it will not effected.  

Honestly adding additional info which might be able to clear the matter:

i) if you would like the muscular tissue to be fixed by NBF (to be -in the end - stained with H&E ONLY) and then stored for an indefinite (not forseeable/predictable) duration there are 'two and a half'  options:

first: you fix with 10% NBF = equals 4% hydrous FORMALDEHYDE-solution (but most better would be true "phosphate buffered" Formaldehyde 4% [specimen thickness not more than say 0.5 cm!] at room temperature at least  for 3-5 hrs, then storage in 4°C fridge (do not freeze!) up to 1 month and longer, followed by routine processing into paraffin.

second: a) you fix with NBF (the former said regarding  true "phosphate buffered" Formaldehyde 4% applies too [specimen thickness not more than say 0.5 cm!] at room temperature at least for 3-5 hrs, then storage in 4°C fridge (do not freeze!) for further 24-30 hrs. Then transfer specimen(s) to suited phosphate buffer [Na-Na-PO4], which is usually in the range 0.1M -015 M, pH 7.2 - pH7.4 (NO, not PBS!), and store in the fridge  up to several weeks, followed by routine processing into paraffin (second b) from the storage buffer you transfer your specimens to 70% Ethanol, where you can also leave your specimens in 7% EtOH for another day(s) until further processing....).

NB: if you have to examine muscle specs for "diagnostic" purposes be aware that today you must use IHC and classical histochemistry (you will not get significant results with H&E only....  but I guess you are aware of!). Such exams can be accomplished using IHC and classical HC on appropriately =rapidly frozen specimens / cryosections from such. Naturally - in most cases - molecular-biological/ mol.-genetic approaches and mutation analyses have to be performed for a satisfying and successful diagnostic purpose, and such will be performed on "native" material (which can be delivered to a special Lab either cooled - or sometimes -  in a special and sophisticated transport medium).

Best wishes and good luck, WM.

Dear Rebecca,

you could also use Bouin´s solution. Fix it for 12 hours, wash it several times in 70% ethanol and then you can store it in 70% ethanol for a considerable time.

Goog luck, Fred

Take the tissue which is 5mm, first wash it with water. Then place in 10% formalin if you would like to postpone the process. Otherwise you can fix it in 50% formalin if want the process it the next day. Then replace it with 50%ethanol for 1hr.then 70% alcohol for 1hr, 90%alcohol for 1hr, absolute alcohol for 1hr. Then clear with xylene 1for 1hr, xylene 2 for 1hr, liquid paraffin 1for 1hr ,paraffin 2 for 1hr. Take Lblocks and put tissue and make blocks. After section cutting and staining you would get very good sections. I have done on skeletal muscle