The importance of correct norms in blood volume measurement.

Accurate individual norms are required for blood volume measurement to be useful in a clinical setting. The primary physiological determinant of normal blood volume is body composition. Norms have been developed based on weight and body surface area, but these have systematic errors arising from variations in body composition or body size. The only norm that specifically estimates body composition uses deviation from ideal weight. A clinically useful norm must also include a normal range that is sufficiently sensitive and specific. The ultimate test of a norm's effectiveness is how it relates to known physiological factors or outcomes in a clinical or research setting. When tested in relation to outcome results from previously published clinical studies, norms utilizing deviation from ideal weight provide the most accurate categorization of blood volume status.

Blood volume and brain natriuretic peptide in congestive heart failure: a pilot study.

BACKGROUND: Brain natriuretic peptide (BNP) levels rise in response to stretch of ventricular myocytes or increases in wall tension, as in congestive heart failure (CHF). Brain natriuretic peptide can be released in bursts, but nonetheless, BNP levels may lag behind clinical changes. We postulated that concomitant measurement of blood volume (BV), BNP, and hemodynamics during treatment of CHF may elucidate interrelationships among changes in these parameters. METHODS: We studied 10 male patients, aged 60 +/- 8 years, who were admitted for pulmonary catheter-guided treatment of CHF. Hemodynamics, venous BNP, and blood and plasma volumes were measured at baseline before treatment and again on the following morning after 12 to 24 hours of acute treatment for CHF. RESULTS: At baseline, all 10 patients exhibited marked expansion of BV at 29% +/- 19%. At baseline, increased systolic pulmonary artery pressure correlated with BV (r = 0.615) and diastolic pulmonary artery pressure (PAD) with BV (r = 0.609). After treatment, there was an inverse correlation between change (decline) in expanded BV and change (improvement) in mixed venous oxygenation (r = -0.775) and a positive correlation with central venous pressure (CVP) (r = 0.710). Poor correlation was found between BNP and any hemodynamic parameter. Little correlation was found between absolute BNP and BV before or after treatment (r = -0.127 and -0.126, respectively). CONCLUSION: In this pilot study, changes in BV with treatment correlate better with hemodynamics than do changes in BNP, likely reflecting the lag in BNP response to treatment and its tendency to reflect long-term rather than instantaneous volume status. These preliminary data suggest that BV may be a more accurate guide in optimizing CHF treatment than BNP.

Successful sperm storage for 28 years.

OBJECTIVE: To report on two instances of successful long-term cryopreservation resulting in live births. DESIGN: Case report. SETTING: The patient stored his sperm at a private sperm banking facility, and his partner underwent artificial insemination at an obstetrics/gynecology practice for one pregnancy and at a fertility center for the other. PATIENT(S): One man who stored his sperm before treatment for cancer. INTERVENTION(S): Storage of sperm under liquid nitrogen in a carousel canister system. Intrauterine insemination in which the semen was thawed, washed with human tubal fluid (HTF), and inseminated. MAIN OUTCOME MEASURE(S): Successful pregnancy resulting in live birth. RESULT(S): Artificial insemination with semen cryopreserved for 21 and 28 years resulted in two live births. CONCLUSION(S): This case report describes the to-date longest known successful cryopreservation of sperm, with two live births resulting from IUI. Successful long-term semen storage can be very beneficial for men facing impaired fertility or sterility early in life, so that they have sufficient time to make appropriate family planning decisions.

The influence of cryoprotective media and processing procedures on motility and migration of frozen-thawed human sperm.

AIM: The study was designed to examine the effects of cryoprotective media, and glycerolating and thawing procedures on human sperm motility and gel penetrating ability. METHOD: Fifteen unselected donors provided semen varying in quality that was distributed in a factorial design across three cryoprotectants (glycerol, egg yolk-citrate-glucose-glycerol and egg yolk-tris-glucose-glycerol). Also, glycerol was added at room temperature versus at 4 degrees C. Two thaw temperatures were tested (laboratory air temperature for 10 min versus a 65 degrees C waterbath for 4 seconds). The proportion of total and progressively motile sperm was estimated immediately after thawing and following incubation at 35 degrees C for 2 h. Migration of sperm for 30 min at 37 degrees C through polyacrylamide gel was tested. RESULTS: Donors differed greatly, with post-thaw total motility of sperm ranging from 9 to 44% (P<0.05). Egg yolk-citrate-glucose-glycerol and egg yolk-tris-glucose-glycerol were superior to glycerol alone (post-thaw values of 35, 37 and 21%, respectively, P<0.05). This was due primarily to poor sperm survival when semen was cooled to 4 degrees C without glycerol or egg yolk. The two thaw temperatures gave similar results. Sperm migration tests paralleled the motility results, but were more sensitive in detecting differences. CONCLUSION: Egg yolk, particularly in a tris-based medium that is widely used in domestic animals, improved the cryopreservation of both good and poor quality human semen.