It is highly unlikely that pears could cause constipation, and in fact they are likely to have the opposite effect. Due to the high amount of fiber that pears contain, they are sometimes used as a remedy for constipation.
An underwriter is a company or other entity that administers the public issuance and distribution of securities from a corporation or other issuing body.
The services of an underwriter are typically used during a public offering. This is a way of distributing a newly issued security, such as stocks or bonds, to investors. A syndicate of banks (the lead managers) underwrites the transaction, which means they have taken on the risk of distributing the securities.