Donald Giacherio

Cardiovascular risk factors in ethnic minority women aged ≤30 years

Men and women of African and South Asian ancestry in the United States are increasingly recognized as being at greater risk for coronary heart disease (CHD) than Caucasians of European ancestry. Relatively little data on the genetic and lifestyle risk factors that predispose women to CHD in these ethnic minorities are available. We compared coronary risk factors in a volunteer sample of African-American, Asian Indian American, and Caucasian American women of college age. Life style, dietary, hemodynamic and anthropometric parameters, and laboratory data were sought from 70 subjects in each ethnic group. African-American women were found to have lower triglyceride levels and higher apolipoproten A-1, high-density lipoprotein (HDL), lipoprotein (a) (Lp(a)), fibrinogen, and fasting insulin levels. They also consumed more fat and cholesterol than their peers, had a higher percentage of body fat, body weight, and body mass indexes, and reported less physical activity than Caucasians. Asian Indian American women had higher Lp(a), HDL, and fibrinogen levels than Caucasian American women, and also reported less physical activity. Thus, young African- American and Asian Indian American women have several modifiable risk factors as well as some nontraditional lipid risk factors that warrant consideration for explaining the increased prevalence of CHD in these ethnic groups. The tendency toward peripheral insulin insensitivity and increased body fat in this age group of African-American women suggests diet and exercise may reduce the risk of subsequent CHD.

Forced TR2/TR4 expression in sickle cell disease mice confers enhanced fetal hemoglobin synthesis and alleviated disease phenotypes

Sickle cell disease (SCD) is a hematologic disorder caused by a missense mutation in the adult β-globin gene. Higher fetal hemoglobin (HbF) levels in red blood cells of SCD patients have been shown to improve morbidity and mortality. We previously found that nuclear receptors TR2 and TR4 repress expression of the human embryonic ε-globin and fetal γ-globin genes in definitive erythroid cells. Because forced expression of TR2/TR4 in murine adult erythroid cells paradoxically enhanced fetal γ-globin gene expression in transgenic mice, we wished to determine if forced TR2/TR4 expression in a SCD model mouse would result in elevated HbF synthesis and thereby alleviate the disease phenotype. In a “humanized” sickle cell model mouse, forced TR2/TR4 expression increased HbF abundance from 7.6% of total hemoglobin to 18.6%, accompanied by increased hematocrit from 23% to 34% and reticulocyte reduction from 61% to 18%, indicating a significant reduction in hemolysis. Moreover, forced TR2/TR4 expression reduced hepatosplenomegaly and liver parenchymal necrosis and inflammation in SCD mice, indicating alleviation of usual pathophysiological characteristics. This article shows that genetic manipulation of nonglobin proteins, or transcription factors regulating globin gene expression, can ameliorate the disease phenotype in a SCD model animal. This proof-of-concept study demonstrates that modulating TR2/TR4 activity in SCD patients may be a promising therapeutic approach to induce persistent HbF accumulation and for treatment of the disease.

Analytical and clinical validation of a radioimmunoassay for the measurement of 1,25 dihydroxy vitamin D

OBJECTIVES The analytical and clinical validation of the DiaSorin 1,25 dihydroxyvitamin D RIA is described. DESIGN AND METHODS The analytical parameters assessed included analytical sensitivity, dilution linearity, intra- and inter-assay precision, recovery, specificity, and interference studies. Where appropriate, assessments were performed according to NCCLS guidelines. The clinical validation assessed normal individuals and end-stage renal disease patients. RESULTS The analytical sensitivity of the assay is < 2.0 pg/mL or < 4.8 pM. The assay is specific for both 1,25 dihydroxyvitamin D2 and D3. Recovery ranged from 97% to 108% for spiked samples. Intra-assay precision, as %CV, ranged from 7% to 11%, while inter-assay precision was 12% to 15%. No interference was observed from bilirubin, cholesterol, hemoglobin, or triglycerides. Clinical validation demonstrated complete discrimination between normal and ESRD populations. CONCLUSIONS These data demonstrate that the DiaSorin 1,25 (OH)(2) vitamin D RIA is a robust, accurate, and precise tool for the assessment of 1,25 (OH)(2) vitamin D.

Half-life determination of serum free prostate-specific antigen following radical retropubic prostatectomy

OBJECTIVES Prostate-specific antigen (PSA) continues to be the the most clinically useful tumor marker for prostate cancer. Recently, several molecular forms of PSA have been detected and characterized. These specific forms, including free PSA and PSA complexed to alpha 1-antichymotrypsin, can be measured and their proportions determined. In doing so, the sensitivity of PSA as a tumor marker can be maintained while the specificity is improved. In order to maximize the clinical utility of free PSA, the half-life and elimination kinetics of free PSA from the serum were determined. METHODS Twenty-five patients, ages 43-74 years (mean 60 years) with biopsy proven, organ-confined adenocarcinoma of the prostate who underwent anatomic radical retropubic prostatectomy, were identified. For each patient, venous blood samples were obtained preoperatively, and at 60-minute intervals beginning 1 hour after the prostate was removed. The specimens were handled and stored in a consistent fashion. Using the AxSYM immunoassay analyzer (Abbott Diagnostics, Abbott Park, IL), the serum free PSA values were determined and plotted as a function of time for each patient. From the 25 individual elimination curves that were generated, the half-life of serum free PSA was determined. RESULTS The mean half-life of serum free PSA was 110 minutes +/- 18.6 minutes (SD). Analysis of the individual and cumulative elimination curves indicates that the elimination of free PSA from the serum following radical prostatectomy follows a biphasic pattern. CONCLUSIONS Unlike PSA, which has a half life of 2-3 days, the half-life of serum free PSA is 110 minutes (1.83 hours). This short half-life may have significant implications for the use of percentage of free PSA as a clinically useful tool in distinguishing patients with early, curable prostate cancer from men with benign prostatic hyperplasia (BPH) only.

Analysis of retinoids by high-performance liquid chromatography using programmed gradient separation

Vitamin A (retinol), its metabolites and analogues have been heavily focused upon due to their clinical value and utility. Retinol can be used as a reflection of dietary or nutritional status, while the retinol analogues (isotretinoin, tretinoin, etretinate) are being proven as potent dermatologic and anti-tumor agents. High-performance liquid chromatography (HPLC) has been demonstrated to be applicable to the measurement of these compounds in blood. HPLC assays have been reported for retinol [l--4], 13&s-retinoic acid [ 5, 61, all-trtrns-retinoic acid [ 7, 81, etretinate [ 9, lo] , plus retinol and retinal isomers [ ll---151. Several assay systems have been reported for the isocratic separation of mixtures of retinoids [ 13-151. Of these, the methods of Frolick et al. [ 141 and McClean et al. [15] allow for the measurement of numerous retinoids in biological specimens through the use of single isocratic systems. Using these methods the required time for separation of compounds can run as long as 36 min [14]. The natural and synthetic retinoids, plus their respective major metabolites, have differences in polarity that make chromatographic separation difficult in a short time period. During the long separation times the later elutmg peaks become broad and require an integrator. To counteract this

Stability of tacrolimus (FK 506) and cyclosporin G in whole blood.

The stability of two new immunosuppressants, tacrolimus and cyclosporin G (CsG), was evaluated in whole blood following incubation of patient specimens at ambient temperature or 4°C for time periods of 2 (48 h) and 7 days (168 h) after collection. No decrease in CsG concentrations was noted over a 7-day period for specimens stored at either ambient temperature or 4°C. For tacrolimus, the concentrations of drug in whole blood stored at ambient temperature for 7 days had a slight downward trend. At 7 days, the ratio of tacrolimus concentrations to day zero concentrations ranged from 0.86 to 1.15, with a mean decrease of 5%. However, these changes are within the published precision characteristics of the tacrolimus immunoassay. Evaluation of a smaller group of whole blood specimens provided evidence of adequate stability of these two drugs over a 13-day period.

Natriuresis associated with elevated plasma atrial natriuretic hormone during supraventricular tachycardia

Elevated plasma levels of atrial natriuretic hormone (ANH) have been found in patients during paroxysmal supraventricular tachycardia (SVT) and other clinical syndromes. However, physiologic effects of this endogenous ANH have not been demonstrated. To determine whether the rise in ANH during SVT is associated with either a natriuresis or kaliuresis, urine sodium and potassium levels were measured in five patients at baseline and during SVT simulated by rapid atrioventricular pacing. Plasma ANH levels increased from 149 +/- 35 pmol/L at baseline to 187 +/- 31 pmol/L (p = 0.007) during SVT. Plasma vasopressin and renin levels were unchanged. Urine sodium levels increased 49% from 1.54 +/- 0.66 mEq/hr at baseline to 2.29 +/- 0.89 mEq/hr (p = 0.044) during SVT, and urine potassium levels increased 22% from 4.14 +/- 0.10 mEq/hr to 5.04 +/- 1.25 mEq/hr (p = 0.018). Urine sodium and potassium levels returned to baseline values 1 hour after pacing. Thus elevated plasma levels of ANH during SVT are associated with both a natriuresis and kaliuresis, which may represent physiologic effects of the endogenously secreted hormone.

The effects of a blood-salvaging device on blood containing a hemoglobin-based oxygen carrier, HBOC-201

OBJECTIVES Hemoglobin-based oxygen carriers will be used concurrently with intraoperative blood salvage. The effects of salvage and processing on blood containing one such solution (HBOC-201; Biopure Corp, Boston, MA) were studied. DESIGN Prospective, randomized. SETTING Laboratory. INTERVENTIONS Sixteen blood units from healthy volunteers had either HBOC (1,500 mg/dL; n = 10) or normal saline (equivalent volume; n = 6) added. All units were salvaged and processed using a blood salvage device. Samples were analyzed for the concentration and molecular weight distribution of plasma hemoglobin and red cell morphology presalvage (pre) and following processing and washing (post 1). Five of the HBOC units underwent a second 1,000 mL wash (post 2). MEASUREMENTS AND MAIN RESULTS Processing and washing decreased the concentration of plasma hemoglobin (mg/dL) in HBOC units (1311 +/- 265 pre to 27.8 +/- 19.6 post 1 to 6.5 +/- 2.19 post 2), but did not change the plasma hemoglobin concentration in saline units (2.05 +/- 1.27 pre v 3.18 +/- 0.79 post 1). Total plasma hemoglobin in HBOC units (6.56 +/- 2.19) was significantly greater than in saline units (3.18 +/- 0.79), even after the second wash (post 2). The concentration of unstable hemoglobin in the plasma phase was not different between groups. Red cell morphology was altered by the salvage process but was not different between groups. CONCLUSIONS Salvage and processing of blood containing HBOC yield concentrated red cells that are indistinguishable from those obtained from blood without HBOC. Residual HBOC remains but is unchanged from the HBOC initially administered.

Effect of dose on the nasal absorption of epinephrine during cardiopulmonary resuscitation

Abstract Delay in epinephrine administration during cardiopulmonary resuscitation (CPR) due to technical difficulties in obtaining an access site may be detrimental. To avoid this potential delay, we have previously shown that intranasal administration of phentolamine and epinephrine is a rapidly obtainable and feasible route of administration during CPR. The objective of this study was to determine the optimal dose of phentolamine and epinephrine to be administered during CPR. A randomized blinded dose ranging study was performed in a controlled laboratory environment. Thirty-six mongrel dogs were randomized to one of the following dosage regimens: phentolamine, 0.25 or 2.5 mg/kg/nostril; epinephrine, 0.075, 0.75, or 7.5 mg/kg/nostril. Phentolamine was administered intranasally 1 minute before the intranasal administration of epinephrine to improve absorption. Each dog underwent 3 minutes of ventricular fibrillation followed by 7 minutes of closed chest CPR. Epinephrine was administered at 3 minutes of CPR. Data from 26 dogs were included for analysis. Treatment B (0.25 and 7.5 mg/kg/nostril of phentolamine and epinephrine, respectively) produced the greatest elevation in coronary perfusion pressure (17 ± 11 vs 4 ± 3 mm Hg for the next highest group, P 5 5 ) versus 0% to 50% for the other groups (P

Lipoprotein (a): Perspectives from a lipid-referral program

BACKGROUND Lipoprotein (a) [Lp(a)] has a strong association with coronary disease (CHD). We evaluated the implications of implementing a niacin strategy in persons above low risk by the Framingham risk score (FRS). METHODS Patients referred to a university lipid management program from January 2004 to June 2010 had an Lp(a) level measured at initial evaluation. Factors associated with an increase in Lp(a) and predictors of a high risk Lp(a) (≥50 mg/dL) were assessed. FRS and Lp(a) levels were used to assess eligibility for niacin with an Lp(a) ≥50 mg/dL. RESULTS A total of 692 patients (57% male, mean age 52 ± 14 years) had a mean Lp(a) of 32 ± 40 mg/dL. In a multiple logistic regression model, African-American race, female gender, presence of CHD, and lower triglyceride levels were significant predictors of high risk Lp(a). Ten percent were determined to be intermediate and 44% high risk by FRS. A total of 9% of intermediate- and 26% of high-risk patients had an Lp(a) ≥50 mg/dL, and 84% were not taking niacin. A total of 19% of moderate- and high-risk patients were eligible for initiation of niacin based upon values ≥50 mg/dL. If niacin were also used for an high-density lipoprotein cholesterol levels ≤40 mg/dL, only 5.1% additional patients would require niacin. CONCLUSION High-risk levels of Lp(a) are associated with female gender, African- American race, and CHD. 19% of moderate and high risk patients would be candidates for treatment with niacin if the indication is a cutpoint Lp(a) ≥50 mg/dL.