Sales and marketing expenses increased $2.9 million, or 58.0%, to $8.0 million for the six months ended June 30, 2010 compared with $5.1 million for the six months ended June 30, 2009. This increase was primarily due to the expenses of our Denville Scientific subsidiary of $2.3 million and increased marketing efforts in all of our businesses.

General and administrative expenses increased $1.2 million, or 17.5%, to $8.1 million for the six months ended June 30, 2010 compared with $6.9 million for the six months ended June 30, 2009. The year-to-year increase was primarily due to $0.5 million of expenses at our Denville subsidiary, a $0.2 million increase in stock compensation expense, and a $0.5 million increase in other general and administrative areas combined.

Research and development expenses increased 10.6%, or $0.2 million, to $2.3 million for the six months ended June 30, 2010 compared with $2.1 million for the same period in 2009. The increase in research and development expenses was primarily due to $0.2 million of spending related to regenerative medicine and increased development efforts in the Biochrom business, which were partially offset by decreased expenses in the Harvard Apparatus business.

Other income and expense, net, was $29,000 expense and $0.4 million expense for the six months ended June 30, 2010 and 2009, respectively. Net interest expense was $0.2 million for the six months ended June 30, 2010 compared to net interest expense of $0.1 million for the six months ended June 30, 2009. The increase in net interest expense was primarily due to higher average debt balances in the six months ended June 30, 2010 compared to the prior year period. Other income and expense, net, also included foreign exchange losses of $0.1 million for the six months ended June 30, 2010 and $0.3 million for the six months ended June 30, 2009. Also included in other income and expense, net, was a $0.4 million gain from adjustment of the contingent consideration related to our Denville Scientific acquisition. Other income and expense, net, for the six months ended June 30, 2010 and 2009, respectively, also included $0.1 million of direct acquisition costs.