Amazon says strong gains in its market leading cloud computing services have helped drive a 15 per cent rise in total sales in the first quarter. But the bottom line was red for the leading US online retailer, with a loss of US$57 million (A$73.30 million), compared to a net gain of US$108 million a year ago, due to continued growth in operating overhead. Total sales jumped to US$22.72 billion in the January-March period, compared to US$19.74 billion a year ago. US sales gains offset a fall in t