Saute shrimp in butter for 1 minute, or until shrimp turn pink, using a large skillet. Add celery and onions. Cook, stirring, 2 minutes. Add spinach and chinese vegetables. Cover and cook 1 minute. Blend pepper, soy sauce, chicken broth and cornstarch together. Stir into shrimp-vegetable mixture. Cook, stirring until sauce is clear and thickened, about 2 minutes. Serve over beds of fluffy rice.