Beginning a sentence, title Subtitle or Heading
Use words for any number that begins one of these. If possible, reword the sentence so it does not begin with a number (but take care that the rewording doesn't change the meaning or intent).
Three hundred twenty-eight men and 126 women were included in the study.
Better: The study included 328 men and 126 women.
Samples: Twenty-five g of tissue.
Better: Samples: A total of 25 g of tissue.
Beginning a sentence with a year
Avoid beginning sentences with a year; recast the sentence to avoid it.
If you cannot easily recast the sentence, you can begin with the numeric form of the year; however, a reformation of the sentence so the year doesn't start the sentence is preferable.
2005 was the year she first noticed the symptoms.
Better: She first noticed the symptoms in 2005.
When a unit of measure follows a number that begins a sentence, it must be written out as well, even if the same unit is abbreviated elsewhere in the same sentence. Rewording the sentence is preferable.
Two milligrams of DepoMedrol? was administered at 5 p.m.
Better: At 5 p.m., 2 mg of DepoMedrol? was administered.