Trauma Exposure in Migrant Children: Impact on Sleep and Acute Treatment Interventions

Trauma exposure significantly impacts sleep in children. Nightmares are common. Evidence-based therapies are superior to medications but may not always be available in acute settings. No FDA-approved medications exist for the treatment of trauma-related sleep disturbances in youth. The evidence-base for the use of medications is largely based on case reports, retrospective chart reviews, clinical opinion, and adult studies. This evidence is reviewed for a number of medications, including prazosin, trazodone, alpha-2 agonists, quetiapine, and others.

Cultural Considerations and Response to Trauma for Displaced Children at the Border

The United States has long been the leading destination for Latin Americans seeking refuge. However, in the last 7 years, many children from Mexico and northern Central America, composed of El Salvador, Honduras, and Guatemala, have joined this migratory flow. The experience of forced migration is intense, chronic, and complex for children in their home countries, during their journey, and on arrival in the United States. Their stories can inform clinical practices, such as Psychological First Aid and Trauma-Focused Cognitive Behavioral Therapy, to promote resilience in children in vulnerable conditions.

Emotional Dysregulation: A Trauma-Informed Approach

Traumatic experiences, subsequent traumatic stress, and other trauma reactions are common among youth who experience emotional dysregulation. This article highlights key considerations for the delivery of care to emotionally dysregulated youth with histories of trauma. An initial, trauma informed assessment is critical to identify those youth with emotional dysregulation best served by evidence-based, trauma-focused treatments trauma-informed approaches to severely emotionally dysregulated youth, including youth in in-patient and residential settings, can improve emotional and behavioral outbursts while maintaining the safety the milieu. Finally, incorporating awareness of trauma is considered when prescribing psychopharmacologic interventions in severely emotionally dysregulated youth.

The strategies to reduce iron deficiency in blood donors randomized trial: design, enrolment and early retention

BACKGROUND AND OBJECTIVES

Repeated blood donation produces iron deficiency. Changes in dietary iron intake do not prevent donation-induced iron deficiency. Prolonging the interdonation interval or using oral iron supplements can mitigate donation-induced iron deficiency. The most effective operational methods for reducing iron deficiency in donors are unknown.

MATERIALS AND METHODS

'Strategies To Reduce Iron Deficiency' (STRIDE) was a two-year, randomized, placebo-controlled study in blood donors. 692 donors were randomized into one of two educational groups or one of three interventional groups. Donors randomized to educational groups either received letters thanking them for donating, or, suggesting iron supplements or delayed donation if they had low ferritin. Donors randomized to interventional groups either received placebo, 19-mg or 38-mg iron pills.

RESULTS

Iron deficient erythropoiesis was present in 52·7% of males and 74·6% of females at enrolment. Adverse events within 60 days of enrolment were primarily mild gastrointestinal symptoms (64%). The incidence of de-enrolment within 60 days was more common in the interventional groups than in the educational groups (P = 0·002), but not more common in those receiving iron than placebo (P = 0·68).

CONCLUSION

The prevalence of iron deficient erythropoiesis in donors enrolled in the STRIDE study is comparable to previously described cohorts of regular blood donors. De-enrolment within 60 days was higher for donors receiving tablets, although no more common in donors receiving iron than placebo.

Capillary versus venous haemoglobin determination in the assessment of healthy blood donors

BACKGROUND AND OBJECTIVES

To determine the accuracy of fingerstick haemoglobin assessment in blood donors, the performance of a portable haemoglobinometer (HemoCue Hb 201+) was prospectively compared with that of an automated haematology analyzer (Cell-Dyn 4000). Haemoglobin values obtained by the latter were used as the 'true' result.

MATERIAL AND METHODS

Capillary fingerstick samples were assayed by HemoCue in 150 donors. Fingerstick samples from two sites, one on each hand, were obtained from a subset of 50 subjects. Concurrent venous samples were tested using both HemoCue and Cell-Dyn devices.

RESULTS

Capillary haemoglobin values (HemoCue) were significantly greater than venous haemoglobin values (HemoCue), which in turn were significantly greater than venous haemoglobin values by Cell-Dyn (mean ± SD: 14.05 ± 1.51, 13.89 ± 1.31, 13.62 ± 1.23, respectively; P < 0.01 for all comparisons among groups). Nine donors (6%) passed haemoglobin screening criteria (≥ 12.5 g/dl) by capillary HemoCue, but were deferred by Cell-Dyn values (false-pass). Five donors (3%) were deferred by capillary sampling, but passed by Cell-Dyn (false-fail). Substantial variability in repeated fingerstick HemoCue results was seen (mean haemoglobin 13.72 vs. 13.70 g/dl, absolute mean difference between paired samples 0.76 g/dl). Hand dominance was not a factor.

CONCLUSIONS

Capillary samples assessed via a portable device yielded higher haemoglobin values than venous samples assessed on an automated analyzer. False-pass and false-fail rates were low and acceptable in the donor screening setting, with 'true' values not differing by a clinically significant degree from threshold values used to assess acceptability for blood donation.

Preoperative coagulation studies to predict blood component usage in coronary artery bypass graft surgery

Bleeding remains a serious complication of cardiac surgery. Studies indicate that preoperative fibrinogen concentration is an independent predictor of blood loss during coronary artery bypass graft (CABG) surgery. This study evaluates whether fibrinogen concentration is a better predictor of blood usage than the prothrombin time (PT) and activated partial thromboplastin time (aPTT) tests. Patients not taking clopidogrel bisulfate who underwent CABG surgery during a 3-month period at a 350-bed community hospital were included in this prospective study. The parameters evaluated included patient’s age, preoperative coagulation test results (PT, international normalized ratio [INR], aPTT, fibrinogen), and number of blood components transfused. A probability value of less than 0.05 was deemed significant. Thirty-five patients were included in this study. Mean blood usage was 6 units. Patient’s age approached significance as a predictor of blood usage, and fibrinogen levels trended toward significance more than the other coagulation parameters. In this study, the increased age of the patient and low plasma concentrations of fibrinogen were associated with increased blood usage. Although no indicators clearly demonstrated statistical significance, the vast difference in the probability values for patients’ ages and fibrinogen levels indicated that there was a trend toward significance in blood usage for CABG patients. Further studies with larger patient populations are indicated.

Determination of optimal method for antibody identification in a reference laboratory

Methods commonly used for antibody identification are hemagglutination (tube), column agglutination (gel), and solid-phase red cell adherence. Our AABB immunohematology reference laboratory (IRL) conducted a study to determine which antibody identification testing method was optimal for detecting all clinically significant antibodies. Patient specimens were sent to our IRL from August 2008 to September 2009. Routine testing was performed by tube method and then by manual gel and manual solid-phase methods. Of the 254 samples tested, 115 showed agreement in antibody identification with all three methods. The tube method identified all but six clinically significant antibodies. The gel method did not identify 59 clinically significant antibodies. Fifty-six clinically significant antibodies were not identified by solid-phase testing. Tube testing identified 27 clinically insignificant antibodies, primarily cold autoantibodies. Gel and solid-phase methodologies identified two and three cold autoantibodies, respectively. Solid-phase testing failed to detect 12 examples of anti-K. No identifiable pattern of reactivity was found in 13 samples using gel testing compared with 6 for solid-phase and none for tube methodologies. Hemagglutination tube method was the best choice for our IRL because it missed the fewest number of clinically significant alloantibodies. Benefits also included the ability to use various potentiating factors, incubation times, and temperature phases to enhance antibody identification. The tube method provided critical data for determining antibody clinical significance.

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.

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.

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.

Leukemia allotransplants in canine fetuses: influence of host age and immune responsiveness

Myelomonocytic leukemia cells allografted prenatally in some developing purebred Beagle fetuses elicited tumors postnatally in some of the pups. The later in gestation that the inoculum was delivered, the less was the disposition to eventual leukemia, indicating that fetal host age at the time of grafting and tumorigenesis are correlated. The leukemogenic transplants may have grown because of fetal immunoinsufficiency or because they were tolerogenic in the developing immune system. Limited immunologic data for exclusion of the latter possibility are reported.

Thymus lymphocytes. Efflux and restoration phases after peripheral exposure of mice to phytohaemagglutinin

Juvenile Swiss mice experienced significant diminutions in thymic content of both small, non-proliferating and larger, proliferating lymphocytes within 12 hours after intraperitoneal injection of phytohaemagglutinin. These alterations, which may predate alterations in lymphocyte traffic and morphology elsewhere, were interpreted as being the consequence of a massive thymus lymphocyte emigration, not of in situ cytolysis, and were effaced by intrathymic lymphocyte restoration toward control numbers by 24 hours.

Cell-mediated immune response in the developing dog

Purebred Beagle dog fetuses, on gestation day 45, had phytohemagglutinin (PHA) and mouse spleen cell (MSC) responsive cells in spleen but not in thymus. The PHA and MSC responses per 10⁶ spleen cells were respectively unchanged and diminished by postnatal day 90. Thymus cells remained MSC-unresponsive to postnatal day 90; however, they became PHA-responsive (PHA+) on gestation day 50. PHA+ cells per 10⁶ thymus cells increased to postnatal day 3 and declined by postnatal day 90. Their appearance in thymus correlated with the developing dog’s ability to reject a massive leukemia allotransplant and their concentration throughout thymus development correlated with the thymus lymphocyte peripheralization rate.

The incorporation of tritium from thymidine into proteins of the mouse

Tritium from methyl-H(3)-thymidine was found to be incorporated into proteins in mice. This incorporation in the mouse as a whole represented between 1 and 10% of the injected tritium. Tritiated water was not an intermediate. Transmethylation reactions are proposed as a means whereby certain amino acids might have acquired the tritium from thymidine at some stage of its catabolism. The initial (2 hr) ratios of DNA to protein tritium activities per milligram of wet tissue ranged from 5 in two tissues of low DNA synthetic activity (pancreas, liver) to 35 to 40 in two tissues of high DNA synthetic activity (spleen, small intestine). Labeled nuclear protein was coincident with labeled DNA in nuclei, where it constituted less than 2.5% of the total tritium. The significance of the findings is discussed.