The traditional way of identifying amyloid in tissue sections has been staining with Congo red and demonstration of green birefringence under crossed polarizers. The original method of Congo red staining, described by Bennhold in 1922, has undergone several modifications to improve its sensitivity, specificity, and reliability. The most common modification is the alkaline Congo red method described by Puchtler and co-workers in 1962. Specificity is improved by using freshly prepared stain and a staining solution fully saturated with sodium chloride. Amyloid proteins can be further distinguished by autoclaving or by treating the tissue with potassium permanganate or alkaline guanidine. Autoclaving the tissues at 120 C for 30 min causes protein AA to lose its affinity for Congo red. Prolongation of autoclaving to 120 min abolishes the Congophilia of protein AL, but prealbumin-related amyloid shows little or no change. Treatment of the tissue with potassium permanganate causes protein AA and B2-microglobulin amyloid to lose their affinity to Congo red. Protein AA fails to stain with Congo red after treatment with alkaline guanidine for 1 min and protein AL and systemic senile amyloid protein (SSA) after 2 hr. Familial amyloid protein (FAP), prealbumin type, can stand 2 hr of alkaline guanidine treatment without losing its ability to stain with Congo red. Other methods of detection of amyloid include fluorescent stains, e.g., thioflavin T or S, and metachromatic stains such as crystal violet. Immunofluorescence and immunoperoxidase methods are used to identify and classify amyloid proteins in tissues. Antibodies against the P component, proteins AA and AL and FAP have been used with great precision. Due to cross-reactivity, these methods do not differentiate between some types of familial and senile systemic amyloidosis.

before, although it has been suggested that assuming a P ra value of 5 mm Hg results in insignificant differences in CFI (5). In contrast, our findings show that substantial errors occur when right atrial pressure is assumed to be a fixed value. It is interesting to note that Seiler et al. (6) found a better correlation between Doppler-and pressure-derived CFI when a measurement of central venous pressure was included, as compared with those calculations where venous pressure was assumed to be 5 mm Hg. Given that almost one-sixth of patients in our study were assigned to the wrong CFI category when P ra was assumed to be negligible or a fixed value, we believe that measurement of right atrial pressure is imperative when calculating CFI.The FFR and CFI were derived and validated with the inclusion of right atrial pressure. Ignoring P ra in everyday practice debases the fidelity of FFR and may lead to inappropriate therapy in some cases. Similarly, assuming a fixed arbitrary P ra value leads to substantial errors in CFI calculations. Therefore, right atrial pressure should always be measured when calculating these physiologic indexes. If the simplified index P d /P a is used, values between 0.70 and 0.80 mandate recalculation of true FFR, after measurement of P ra .

The hematologic parameters of blood stored at 4 degrees C and at room temperature were studied. In blood stored at 4 degrees C with intermittent mixing, leukocyte count, hemoglobin, erythrocyte count, mean corpuscular volume (MCV), hematocrit, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration (MCHC), and platelet count showed no statistically significant change for three days. Blood stored at room temperature showed a significant increase in MCV in 24 hours, and corresponding changes occurred in hematocrit and MCHC. It is concluded from these observations that blood from normal healthy donors can serve as an adequate control for the Coulter Counter for three days if kept at 4 degrees C and mixed intermittently.

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