Evaluation of low red blood cell mean corpuscular volume in an apheresis donor population

BACKGROUND

Apheresis donors are routinely evaluated with a complete blood count (CBC). Low red blood cell mean corpuscular volume (MCV) values (<80 fL) in the presence of an acceptable hemoglobin (Hb; >or=12.5 g/dL) could be due to iron deficiency or hemoglobinopathy. The etiology of a low MCV in a healthy apheresis donor population was assessed.

METHODS

Predonation samples for CBC were obtained from 1162 consecutive apheresis donors. Donors with a MCV of less than 80 fL were evaluated by CBC, iron studies (ferritin, serum iron, transferrin, percentage of transferrin saturation), and hemoglobin (Hb) electrophoresis. Iron deficiency was defined as a ferritin value below the reference range. Beta chain Hb variants were determined by Hb electrophoresis. Alpha thalassemia trait was presumed if the red blood cell (RBC) count was elevated, no variant Hbs were detected, and the iron studies were within normal ranges.

RESULTS

In a 19-month period, 33 of 1162 apheresis donors had low MCV values. Iron deficiency was present in 64%; 49% had isolated iron deficiency and 15% had iron deficiency plus hemoglobinopathy. Hemoglobinopathy without concomitant iron deficiency was found in the remaining 36%.

CONCLUSION

Iron deficiency is present in the majority of apheresis donors with repeatedly low MCV values and Hb levels of 12.5 g/dL or more. Hemoglobinopathy is also commonly present but may not be easily recognized in the setting of iron deficiency. The MCV is a useful screening tool to detect iron deficiency and hemoglobinopathy. Low MCV values should be investigated to determine if iron replacement therapy is indicated.

Pathogen-reduction methods: advantages and limits

Pathogen‐reduction (inactivation) provides a proactive approach to reducing transfusion‐transmitted infection. Pathogen‐reduction technologies have been successfully implemented by plasma fractionators resulting in no transmission of human immunodeficiency, hepatitis C, or hepatitis B viruses by US‐licensed plasma derivatives since 1987. Fractionation technologies cannot be used to treat cellular blood components. Although blood donor screening, deferral and disease testing have drastically reduced the incidence of transfusion‐transmitted diseases, the threat of new or re‐emerging pathogens remains. Of particular concern is the silent emergence of a new agent with a prolonged latent period in which asymptomatic infected carriers would donate and spread infection. The ultimate goal of pathogen‐inactivation is to reduce transmission of potential pathogens without significantly compromising the therapeutic efficacy of the cellular and protein constituents of blood. The acceptable technology must not introduce toxicities into the blood supply nor result in neoantigen formation and subsequent antibody production. Several promising pathogen‐inactivation technologies are being developed and tested, and others are currently in use, but all of them have limits. Pathogen‐reduction promises an additional ‘layer of protection’ from infectious agents and has the potential to impact the safety of blood transfusions worldwide.

Cost-effectiveness of FDA variance for blood collection from individuals with hereditary hemochromatosis at a 398-bed hospital-based donor center

Hereditary hemochromatosis (HH) is treated by therapeutic phlebotomy to reduce excess body iron. This 398-bed, hospital-based donor center wanted to determine whether there was a financial advantage to requesting FDA approval to allow transfusion of blood components from eligible individuals with HH. Donor center records from 2008 were reviewed to identify all therapeutic phlebotomy patients with a diagnosis of HH. HH patients were contacted and asked to complete the AABB Uniform Donor History Questionnaire (UDHQ) to determine their eligibility as potential allogeneic blood donors. Financial ramifications attributable to loss of revenue from the therapeutic phlebotomies($100/collection) were compared with the potential gain in revenue from collecting units for transfusion ($429/collection) in a 12-month period. Nineteen HH patients were identified and screened for allogeneic eligibility. Seventeen patients (89%) met the eligibility criteria for allogeneic donors, and two patients (11%) did not. Retrospective review of donor records indicated that a total of 60 units were collected from these HH patients from January 2008 through December 2008. Fifty-five of the 60 units collected (92%) were eligible for allogeneic use, potentially generating gross revenue of $23,595. After deducting expenses for infectious disease testing and loss of revenue for the nonqualified therapeutic phlebotomies, the net revenue from the collection of 55 RBC units that could have potentially been used for allogeneic transfusion was $20,345. In contrast, the current revenue generated by the collection of 60 therapeutic phlebotomies was only $6,000. In 2008, using eligible HH individuals as allogeneic blood donors would have resulted in an increase in revenue of $14,345 for our blood center.This study demonstrates that even at a medium-size, hospital-based donor center, obtaining a variance from the FDA to establish an HH blood donor program is a cost-effective endeavor, which does not compromise donor or patient safety.

Bone marrow cell cycle markers in inherited bone marrow failure syndromes

Patients with inherited bone marrow failure syndromes (IBMFS) are at increased risk of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), possibly related to cell cycle dysregulation. In a cross-sectional analysis of bone marrow from 77 IBMFS, 71 sporadic conditions (AML, MDS, acquired aplastic anemia) and 22 normal controls we found overexpression of p53 in IBMFS, AML, and MDS; of Ki-67 in IBMFS and AML; and of survivin in IBMFS compared with all other groups. The patterns of expression of cell cycle markers in IBMFS are thus distinct. Longitudinal studies will determine the diagnostic and prognostic significance of these findings.

Cryopreserving and deglycerolizing sickle cell trait red blood cell components using an automated cell-processing system

RBC components with rare phenotypes are sometimes required for patients with sickle cell disease, and these rare components can often be found among donors with sickle cell trait. Cryopreserving RBC components from sickle cell trait donors requires a modified deglycerolization method to preserve the integrity of the RBCs. This study evaluated the feasibility of using an automated cell-processing system to cryopreserve and deglycerolize sickle cell trait donor RBC components. CP2D/AS-3 RBC components were collected from three donors with sickle cell trait. Each component was processed with an automated cell-processing system (ACP 215, Haemonetics Corp., Braintree, MA) and cryopreserved within 6 days of collection. The components were stored at -65 degrees C or less for at least 2 days and were deglycerolized using the automated cell-processing system's standard procedure. Before cryopreservation and after deglycerolization, several variables were measured. Deglycerolization resulted in recovery of 43.0, 76.5, and 67.5 percent of RBCs from the three sickle-cell-trait donor components compared with 80 percent or greater for all six control components. A small, dark red, jelly-like mass was noted in the bowl of the disposable set after deglycerolization of each of the three RBC sickle cell trait components. The osmolalities of all three sickle cell trait components were less than 400 mOsm/kg, but only one of the three was acceptable for a 14-day outdate. Freezing and deglycerolization of sickle cell trait donor RBC components with the automated cell-processing system resulted in recovery of some RBCs, but a decrease in RBC recovery was problematic. Modifications of the procedure are needed for processing sickle cell trait donor RBC components.

Leukoreduction filtration of whole-blood units from sickle trait donors: effects of a metered citrate anticoagulant system

BACKGROUND

Polymerization of hemoglobin (Hb) S is exacerbated by acidic and hyperosmotic citrate anticoagulant solutions and often results in occlusion of leukoreduction filters by red blood cells (RBCs) from sickle cell trait (Hb AS) donors. This study evaluates a blood collection instrument that adds citrate anticoagulant in a metered fashion, thus mitigating adverse citrate effects.

STUDY DESIGN AND METHODS

Collection of whole blood by a metered anticoagulant system was compared to traditional phlebotomy in 12 Hb AS and 12 non-sickle trait (Hb AA) donors. Each donated twice; on one occasion, units were filtered after 4-hour storage at 20 to 24 degrees C, and on the other, units were stored at 1 to 6 degrees C for 24 hours before filtration.

RESULTS

Filtration times, RBC recoveries, and residual white blood cell (WBC) counts met defined criteria more often in Hb AS units collected by a metered anticoagulant system (9 of 12, 8 of 12, and 4 of 12, respectively) compared to traditional phlebotomy (1 of 12, 2 of 12, and 0 of 12, respectively). Overall, Hb AS units filtered better after storage at 1 to 6 degrees C for 24 hours, with units collected by a metered anticoagulant system undergoing filtration most effectively (5 of 6 had >85% RBC recovery, 3 of 6 had <5 x 10(6) residual WBC). Units exhibited similar changes in RBC storage parameters.

CONCLUSION

Use of a metered anticoagulation instrument demonstrates potential for successful leukoreduction and acceptable storage of Hb AS units; however, the system needs further modifications and improvements before it can be utilized to collect and leukoreduce Hb AS blood.

Pathogen inactivation: the definitive safeguard for the blood supply

CONTEXT

Pathogen inactivation provides a proactive approach to cleansing the blood supply. In the plasma fractionation and manufacturing industry, pathogen inactivation technologies have been successfully implemented resulting in no transmission of human immunodeficiency, hepatitis C, or hepatitis B viruses by US-licensed plasma derivatives since 1985. However, these technologies cannot be used to pathogen inactivate cellular blood components. Although current blood donor screening and disease testing has drastically reduced the incidence of transfusion-transmitted diseases, there still looms the threat to the blood supply of a new or reemerging pathogen. Of particular concern is the silent emergence of a new agent with a prolonged latent period in which asymptomatic infected carriers would donate and spread infection.

OBJECTIVE

To review and summarize the principles, challenges, achievements, prospective technologies, and future goals of pathogen inactivation of the blood supply.

DATA SOURCES

The current published English-language literature from 1968 through 2006 and a historical landmark article from 1943 are integrated into a review of this subject.

CONCLUSIONS

The ultimate goal of pathogen inactivation is to maximally reduce the transmission of potential pathogens without significantly compromising the therapeutic efficacy of the cellular and protein constituents of blood. This must be accomplished without introducing toxicities into the blood supply and without causing neoantigen formation and subsequent antibody production. Several promising pathogen inactivation technologies are being developed and clinically tested, and others are currently in use. Pathogen inactivation offers additional layers of protection from infectious agents that threaten the blood supply and has the potential to impact the safety of blood transfusions worldwide.

Paraplegia as the presenting manifestation of extramedullary megakaryoblastic transformation of previously undiagnosed chronic myelogenous leukemia

Extramedullary tumors, also known as granulocytic sarcomas (GS), occur most frequently in acute myelogenous leukemia (AML). They may signal the onset of the accelerated phase of chronic myelogenous leukemia (CML) or the blastic transformation of a myeloproliferative disorder. Occasionally, a GS may be the presenting sign of undiagnosed AML, and rarely the presenting sign of undiagnosed CML or aleukemic leukemia. Paraplegia due to a spinal cord GS is an extremely rare presentation of undiagnosed leukemia. This is the first case report of paraplegia as the presenting manifestation of extramedullary megakaryoblastic transformation of previously undiagnosed CML. A 53-year-old woman reported back pain for 6 days, rapidly progressing to paraplegia. Physical examination noted a large abdominal mass and flaccid paralysis in both lower extremities. Spinal MRI revealed a T4-T6 vertebral mass causing spinal stenosis and cord compression. Tumor debulking and laminectomy were performed emergently. The tumor consisted of noncohesive blast cells. The CBC revealed a leukocyte count of 238,300/microl and a differential consistent with CML. Reexamination of the patient found that the abdominal mass was a giant spleen. Further immunohistochemical studies of the tumor were consistent with extramedullary acute megakaryoblastic blast transformation of CML. Although extramedullary blast crises herald the accelerated phases in approximately 10% of CML cases, megakaryoblastic blast transformation of CML accounts for less than 3% of these cases. The combination of acute paraplegia and megakaryoblastic transformation in a previously undiagnosed patient with CML is extremely rare and may pose a diagnostic dilemma.

Sequestration of anti-Cra in the placenta: serologic demonstration by placental elution

BACKGROUND

Few cases of antibodies to the Cromer (a) antigen have been described during pregnancy. Interestingly, the anti-Cr(a) titers decreased during pregnancy, and although the newborns were Cr(a)+, the direct antiglobulin tests (DATs) were negative and hemolytic disease of the newborn (HDN) was not observed. Cromer antigens reside on the decay-accelerating factor (DAF), which is expressed on the fetal derived syncytiotrophoblast layer of the placenta. It has been postulated that Cromer antibodies are not transported to the fetus, but are bound to placental DAF, thereby protecting the fetus from HDN and causing the disappearance of Cromer antibody in maternal plasma. This report is the first to demonstrate Cromer antibody sequestration by the placenta.

CASE REPORT

A G4P1 woman with an anti-Cr(a) presented for prenatal care during her fourth pregnancy. The anti-Cr(a) titer decreased from 64 at 7 weeks gestation to undetectable after 25 weeks. At delivery, the infant had no evidence of HDN. The infant's DAT was negative, and the maternal plasma, cord plasma, and the cord blood eluate were negative with screening cells, the infant's cord cells, and the mother's cells. Placental eluates revealed anti-Cr(a).

CONCLUSIONS

This is the fourth case report of a Cromer (a-) woman producing anti-Cr(a) during pregnancy, and the first demonstrating anti-Cr(a) sequestration in the placenta. The presence of anti-Cr(a) in the placental eluate, but not in the cord plasma, maternal plasma, or cord blood eluate, strongly supports the hypothesis that DAF at the fetomaternal interface absorbs anti-Cr(a) from the maternal circulation blocking its passage to the fetus.

Blood bank on-call physician's experiences at a large university medical center

BACKGROUND

The responsibilities of the blood bank on-call physician (blood bank physician from here on) encompass many aspects of transfusion medicine and physician education. This physician is available 24 hours a day to address any issues concerning the collection and transfusion of blood and blood components. The purpose of this study was to identify and categorize the issues that may confront a blood bank physician.

STUDY DESIGN AND METHODS

Each call received over a 4-month period was logged and the resolution documented. The calls were grouped into five categories: donor issues, therapeutic procedure issues, patient issues, physician education issues, and requests for blood components not meeting previously defined transfusion guidelines.

RESULTS

The blood bank physician received 224 calls during the study period. To resolve each issue, an additional 1 to 14 telephone calls were needed to gather further information. Number of calls by category were donor issues, 20 (8.9%); therapeutic procedure issues, 9 (4.0%); patient issues, 4 (1.8%); physician education issues, 33 (14.7%); and requests for blood components not meeting previously defined transfusion guidelines, 158 (70.6%). Requests for blood components were denied in 39.8 percent of the cases not meeting guidelines. Other forms of therapy were warranted in 20.9 percent of the cases.

CONCLUSION

This study revealed that 85.3 percent of the calls referred to the blood bank physician related to physician education and the appropriateness of blood component orders. These results emphasize the need for ongoing education of medical staff in transfusion medicine issues.

HIV pharmacogenomics: closer to personalized therapy?

Pharmacogenomics classically focuses on host nuclear genetic polymorphisms that can be used to predict adverse drug reactions (ADRs). Because ADRs are defined as any noxious, unintended, and undesired drug effects, loss of efficacy due to the development of antiretroviral drug resistance and both acute and cumulative adverse effects of antiretroviral therapy can be considered ADRs. In order to address these types of antiretroviral-associated ADRs, pharmacogenomic testing methods have expanded to include molecular assays that characterize extranuclear genetic material (e.g. HIV and mitochondrial genomes), as well as the host nuclear genetic material. Recent molecular advances permit high resolution resistance testing that detects loss of therapeutic efficacy through the use of phenotypic, genotypic and/or virtual phenotypic resistance testing. These assays use complex technical and interpretative methods to improve the therapeutic efficacy of antiretroviral therapy. The resistance assays demonstrate the utility of pharmacogenomic testing for patients undergoing lifelong and complex antiretroviral therapies. Future applications of antiretroviral-directed pharmacogenomic tests range from quantitative detection of mitochondrial depletion as an early surrogate marker for drug toxicity, to qualitative analysis of host immune haplotypes, and metabolic/transporter genetic polymorphisms for predicting disease progression. In summary, pharmacogenomic testing for HIV-positive patients provides proof of principle that these tests can be used clinically to improve outcomes for patients undergoing complex and sustained drug regimens.

Effects of short-term use of ibuprofen or acetaminophen on bone resorption in healthy men: a double-blind, placebo-controlled pilot study

Prostaglandins are known to be involved in the metabolism of bone, having a significant influence on bone resorption in cases of bone pathology. We therefore investigated the short-term effects of two commonly used nonsteroidal anti-inflammatory drugs (NSAIDs), ibuprofen and acetaminophen (paracetamol), on bone resorption in healthy men. In a randomized, double-blind pilot study, 28 healthy, age- and weight-matched male volunteers were treated with ibuprofen (n = 10), acetaminophen (n = 9), or a placebo (n = 9) for 3 days. As an indication of bone resorption rate, levels of the biochemical bone markers N-telopeptide (NTx) and free deoxypyridinoline (D-Pyr) were measured in urine. Differences in resorption marker levels pre- and post-NSAID use were then compared between groups. We found that NTx concentrations in the acetaminophen group were lower than placebo (p = 0.048), whereas NTx levels in the ibuprofen group were higher than in the acetaminophen group (p = 0.016). By contrast, D-Pyr concentrations in the ibuprofen group were significantly lower than in the placebo group (p = 0.009). A comparison of the percentage changes of D-Pyr:NTx ratios found that the ratio in the ibuprofen group was significantly lower than that of both the control (p = 0.0065) and acetaminophen (p = 0.01) groups. These results show the differential effects of ibuprofen and acetaminophen on urinary excretion of peptide-bound and free deoxypyridinoline cross-links of type I collagen. Short-term ibuprofen use may alter the renal handling of collagen cross-links and increase bone resorption to a greater extent than acetaminophen in normal men.

Toxicity of monochloroacetic acid administered by gavage to F344 rats and B6C3F1 mice for up to 13 weeks

Groups of 20 rats and 20 mice of each sex were administered monochloroacetic acid (MCAA) once daily, 5 days per week, in water by gavage for up to 13 weeks. Doses used were 0, 30, 60, 90, 120, or 150 mg/kg for rats and 0, 25, 50, 100, 150, or 200 mg/kg for mice. Compound-related deaths occurred at the four highest dose levels in rats and at the highest dose level in mice. Mean body weights of treated groups of rats and mice surviving until the end of the study were similar to those of the controls. A dose-related increase in blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase, as well as a dose-related increase in the relative liver and kidney weights was observed in rats but not in mice. A dose-related increase in the incidence and severity of cardiomyopathy occurred in rats. This lesion may be related to the inhibition of heart mitochondrial aconitase activity. No compound-related lesions were observed in mice. The results of this study indicate that F344 rats are more sensitive than B6C3F1 mice; sexes within the species were equally sensitive. The no-observable-effect level was estimated as 30 mg MCAA/kg body weight for rats and 100 mg MCAA/kg body weight for mice.

An experience with upper-extremity vascular trauma

In this 6-year study of 101 limbs requiring surgical intervention for upper-extremity vascular trauma, most patients were male, young, and injured by penetrating objects. Injured vessels included 13 axillary/subclavian, 23 brachial, 40 radial, and 25 ulnar arteries. Concomitant injuries included nerve injury in 50 cases, tendon laceration in 29, and bony fracture in 11. Arterial repair was accomplished by primary repair in 54 limbs, vein graft in 26 limbs, and vein patch in 3 limbs. Seventeen arterial injuries were ligated. Ancillary procedures included 30 nerve or 27 tendon repairs. The limb salvage rate was 99%. No functional deficits were noted in those cases with only a vascular injury. In 64% and 25% of patients with nerve or musculoskeletal injury, respectively, the arm was functionally impaired. Prompt diagnosis and surgical intervention eliminate vascular injury as a factor in upper-extremity limb loss or disability. Functional deficits are the result of nerve or orthopedic injuries.

The CO2 laser as an intraluminal repair tool

The CO2 laser can weld vessels together and vaporize plaque. This study evaluates its use as an intraluminal reparative tool. In 17 dogs, a 1-cm circumferential intimectomy with a 1-mm distal intimal flap was performed in both carotids. In each dog, one carotid (CON, control) underwent suture flap repair. On the contralateral side (LR, laser repair), the flap was tacked with 20 250-mW 1-sec pulses and the denuded medium was g-lased for 90 sec (250 mW continuous). Animals were randomized into five groups and sacrificed on the day of surgery (Group I, n = 3), at 3 days (Group II, n = 3), at 1 week (Group III, n = 4), at 2 weeks (Group IV, n = 4), or at 4 weeks (Group V, n = 3). Vessel patencies were 88.2 and 82.4% for CON and LR, respectively. Flap repair appeared similar. No aneurysms were noted. Histology revealed a relative absence of platelet adherence to the g-lased surfaces in Groups I and II when compared to that of mechanical methods (CON). The ratio of the thickness of the regenerated surface to the total wall thickness demonstrated hyperplasia in LR vessels (0.54 +/- 0.12) when compared to that in CON (0.30 +/- 0.15) at 2 and 4 weeks (ANOVA, P less than 0.001). Coverage with endothelial-like cells appeared complete at 4 weeks in both methods. The CO2 laser can effectively repair intimal flaps. However, our results demonstrate a significant increase in medial hyperplasia following g-lasing even in the face of minimal early platelet adherence. This may prove detrimental to the long-term patency of intraluminal CO2 laser-treated vessels.

A CASE-SAR study of mammalian hepatic azoreduction

A group of 36 aryl azo dyes were examined for their ability to be reduced by rat liver microsomal azoreductase. This group of azo dyes featured a variety of substituents, including sulfonic acid, phenol, nitro, amide, and methyl functionalities on phenyl, alpha-naphthyl, and beta-naphthyl rings. Reduction rates for each dye were obtained using a spectrophotometric method and anaerobic incubation conditions. These rates ranged from 0 to 7.35 nmol dye reduced/min.mg protein. The reduction rates and dye structures provided the data for a CASE-SAR (computer automated structure evaluation-structure-activity relationship) fragment analysis, and three major structure fragments associated with the ability of this group of azo dyes to be reduced were identified. The three CASE fragments correctly label 92% of the azo dye structures as active or inactive and may be useful in future predictions of the ability of azo dyes to undergo reduction by rat liver azoreductase.

Morphological transforming activity and metabolism of cyclopenta-fused isomers of benz[a]anthracene in mammalian cells

4 isomeric cyclopenta-derivatives of benz[e]anthracene (benz[a]aceanthrylene, benz[j]aceanthrylene, benz[l]aceanthrylene, and benz[k]acephenanthrylene) were examined for their ability to morphologically transform C3H10T1/2CL8 mouse-embryo fibroblasts. All of these polycyclic aromatic hydrocarbons studied except benz[k]acephenanthrylene transformed C3H10T1/2CL8 cells to both type II and type III foci in a concentration-dependent fashion. Benz[j]aceanthrylene was the most active, equivalent in activity to benzo[a]pyrene on a molar basis, in producing dishes of cells with transformed foci (94% at 1.0 microgram/ml). Benz[e]aceanthrylene, and benz[l]aceanthrylene produced 58% and 85% of the dishes with foci respectively at 10 micrograms/ml. Metabolism studies with [3H]benz[j]aceanthrylene in C3H10T1/2CL8 cells in which unconjugated, glucuronic acid conjugated, and sulfate conjugated metabolites were measured indicated that the dihydrodiol precursor to the bay-region diol-epoxide, 9,10-dihydroxy-9,10-dihydrobenz[j]aceanthrylene, was the major dihydrodiol formed (55%). Smaller quantities of the cyclopenta-ring dihydrodiol, 1,2-dihydroxy-1,2-dihydrobenz[j]aceanthrylene (14%), and the k-region dihydrodiol, 11,12-dihydroxy-11,12-dihydrobenz[j]aceanthrylene (5%) were also formed. Similar studies with [14C]benz[l]aceanthrylene indicated that the k-region dihydrodiol, 7,8-dihydroxy-7,8-dihydrobenz[l]aceanthrylene was the major metabolite formed (45%). The cyclopenta-ring dihydrodiol, 1,2-dihydroxy-1,2-dihydrobenz[l]aceanthrylene and 4,5-dihydroxy-4,5-dihydrobenz[l]aceanthrylene were formed in minor amounts (less than 6%). Therefore, metabolism at the cyclopenta-ring of B(j)A and B(l)A is a minor pathway in C3H10T1/2CL8 cells in contrast to previously reported studies with cyclopenta[cd]pyrene in which the cyclopenta-ring dihydrodiol was the major metabolite. These results suggest that routes of metabolic activation other than oxidation at the cyclopenta-ring such as bay region or k-region activation may play an important role with these unique polycyclic aromatic hydrocarbons in C3H10T1/2CL8 cells.

Metabolism of benzo(a)pyrene in monolayer cultures of human bronchial epithelial cells from a series of donors

Benzo(a)pyrene [B(a)P] metabolism was measured in monolayer cultures of human bronchial epithelial cells derived from 18 specimens of explanted tissue. Bronchial epithelial cells converted B(a)P to dihydrodiols, phenols, quinone derivatives, and polyhydroxylated forms. Sulfate and glucuronide conjugates of B(a)P metabolites were also detected. Both total metabolism and distribution of metabolites showed a 10-fold or greater variation in cultures from different specimens. When the data were divided according to smoking status, however, no differences in total metabolism, extent of conjugation, or distribution of metabolites could be demonstrated between the two groups. Wide variation (over 1000-fold) in the cytotoxicity of B(a)P towards cells derived from different specimens was demonstrated but could not be directly correlated to the extent of metabolic activation. The results suggest that human bronchial epithelial cells which are newly grown from explanted tissue of smokers in culture do not demonstrate enzymatic induction. Variation among individuals observed in these studies probably represents basal differences in metabolic capability.

Quantitative analysis of the metabolism of benzo(a)pyrene by transformable C3H10T1/2CL8 mouse embryo fibroblasts

The metabolism of benzo(a)pyrene [B(a)P] to organic soluble and water soluble metabolites by transformable C3H10T1/2CL8 mouse embryo fibroblasts was studied as a function of time, B(a)P concentration, and cell density. The total formation of organic-soluble and water-soluble metabolites increased with incubation time from 4 to 48 h and with B(a)P concentration from 4 to 40 microM. As cell density increased, the metabolic rate decreased for organic-soluble and water-soluble products between 6,300 and 54,000 cells/cm2 probably due to decreases in B(a)P concentrations to values below saturation. Specific organic-soluble metabolites identified were B(a)P-pre-9,10-diols, B(a)P-9,10-diol, B(a)P-7,8-diol, B(a)P-3,6-quinone, B(a)P-3-phenol, and B(a)P-9-phenol. Water-soluble metabolites were subjected to enzymatic hydrolysis with beta-glucuronidase and aryl sulfatase to identify specific conjugated products. The sulfate conjugated metabolites identified were B(a)P-7,8-diol, B(a)P-pre-9,10-diols, B(a)P-9,10-diol, and B(a)P-3,6-quinone. The beta-glucuronic acid metabolites identified were B(a)P-pre-9,10-diols, B(a)P-3,6-quinone, and B(a)P-3-phenol. Patterns of metabolite formation rates are discussed as to their possible effect on morphological transformation rates in C3H10T1/2 cells with respect to incubation time and cell density.

Metabolism of alpha-naphthoflavone by rat, mouse, rabbit, and hamster liver microsomes

The metabolism of alpha-naphthoflavone (ANF) was studied in hepatic microsomes from rats, mice, rabbits, and hamsters, species in which ANF exerts its biological activities. The major metabolites produced by all species were ANF-5,6-oxide, ANF-6-phenol, and ANF-7,8-dihydrodiol. Minor metabolites produced by all species were ANF-5,6-dihydrodiol, ANF-7-phenol, and ANF-9-phenol. In general, the total rates of metabolism were similar within all species: 22-32 nmol ANF metabolized/15 min/mg protein. Mouse liver microsomes were approximately 1.7 to 2.9 times as active as the other species on a nanomole of cytochrome P-450 basis. The major sites of enzymatic oxidation were the 5,6 and 7,8 bonds of ANF where for all species, 49-71% and 15-46% of the total metabolism occurred, respectively.

Reanalysis and clarification of the structures of alpha-naphthoflavone dihydrodiols formed by uninduced and induced rat liver microsomes from Charles River CD and Sprague-Dawley rats

The structures of alpha-naphthoflavone (ANF) dihydrodiols formed by uninduced and induced rat liver microsomes are identified by conversion of the metabolically formed ANF-dihydrodiols to the corresponding phenols. Comparison of these phenols with synthetic standards provides an unambiguous method for structural identification. The results of these studies are that hepatic microsomes from uninduced or phenobarbital, Aroclor-1254, 3-methylcholanthrene, or 5,6-benzoflavone induced Sprague-Dawley or Charles River CD rats each produce a major and a minor ANF-dihydrodiol identified as ANF-7,8-dihydrodiol and ANF-5,6-dihydrodiol, respectively.