THE DIAGNOSIS OF IRON DEFICIENCY BY ERYTHROCYTE PROTOPORPHYRIN AND SERUM FERRITIN ANALYSES

ABSTRACT. Free erythrocyte protoporphyrin (FEP) and serum ferritin have been determined in 57 healthy children and in 25 children with varying degrees of iron deficiency. FEP was found to be inversely correlated to the concentration of hemoglobin (r=-0.80) as well as to serum ferritin (r=-0.64). Elevated FEP was found in children with hemoglobin less than 12.5 g/dl, or serum ferritin less than 8 μg/l. In a group of apparently hematologically normal children between the age of 10–14 years (hemoglobin≥ 12.5 g/dl), a 2-month-trial of iron medication resulted in an increase in hemoglobin and ferritin, and a decrease in FEP, indicating suboptimal supply of iron for hemoglobin synthesis before iron medication. In a patient with iron deficiency (FEP 15.3 μmole/l, hemoglobin 5.2 g/dl), iron therapy was followed by a rapid fall in FEP before any changes in hemoglobin, serum iron transferrin saturation and ferritin could be detected. The rapid fall in FEP during start of treatment in iron deficiency makes FEP a sensitive biochemical parameter on iron homeostasis in iron deficiency anemia.     

Immunotoxicity Testing: An Economical Multiple-Assay Approach

Immunotoxicity Testing: An Economical Multiple-Assay Approach.EXON, J.H., KOLLER, L.D., TALCOTT, P.A., O'REILLY, C.A., ANDHENNINGSEN, G.M. (1986). Fundam Appl. Toxicol. 7, 387-397. Amodel for assessing immunotoxicologic effects of chemicals anddrugs was developed in the Sprague-Dawley rat whereby multipleconcomitant immunoassays were performed in a single animal.The multiple parameters of immunity assessed in each rat includedT cell-dependent IgG antibody production, delayed hypersensitivity,natural killer cell cytotox-icity, and production of three potentimmune regulating immunocytokines: macrophage-de-rived interleukin1 and prostaglandin E2, and lymphocyte-derived interleukin 2.Splenocyte and resident peritoneal macrophage numbers were alsoquantitated and spleen and thymus weights recorded. The sensitivityof this animal model was tested by treating rats with the immune-potentiatingdrugs, NPT 15392 (erythro-9-[2-hydroxy,3-nonyl]hypoxanthine)and avridine (N, N-dioctadecyl-N', N'-bis-[2-hydroxyethyl]propanediamine,or the immune-suppressive drugs, cyclophosphamide (N, N-bis[2-chloroethyl]tetrahydro-2H-1,3,2-oxazaphosphorin-2-amine-2-oxide)and dexamethasone. Rats treated with NPT 15392 or avridine generallyhad enhanced immune responses, while those treated with cyclophosphamideor dexamethasone had decreased immune responses. Differentialresponsiveness of various immunocyte populations within individualrats to different drugs, or to doses of the same drug, indicatesthe efficacy of measuring multiple responses within the sameanimal. The multiassay-single animal approach represents aneconomical, versatile, sensitive, and relatively comprehensiveparadigm for assessing immunotoxicologic/pharmacologic propertiesof chemicals and drugs. The approach is extremely economicalsince multiple immune responses are evaluated in each animal.The approach is versatile because it is amenable to incorporationof a variety of in vitro and in vivo assays and could be appliedto almost any species. The model is relatively comprehensivebecause major types of immune responses/immunocyte populationsand immunoregulatory pathways are tested. Finally, the modelis sensitive for detecting immunosuppression as well as immunoenhancement,as validated by the use of known immune response modifiers inthis Study.     

Influence of Different Conditioning Methods on Force and Fatigue Resistance in Chronically Stimulated Skeletal Muscles

A study was undertaken to compare different conditioning methods for the transformation of latissimus dorsi muscle into a fatigue resistant one for application in circulatory assist. In ten sheep four electrodes were sutured to the epineurium of the left thoracodorsal nerve for indirect electrical stimulation of the latissimus dorsi muscle. In six sheep a "carousel stimulation, " a special multichannel stimulation, in combination with a recently developed conditioning protocol was used for muscle conditioning ( multichannel method ). In four sheep, a conventional stimulation protocol using single channel stimulation was applied for transformation of the muscle (single channel method). The final experiments were carried out when fatigue resistance was obtained. The maximum tetanic forces at different preloads were determined and fatigue resistance was tested during 20 minutes of continuous stimulation. Both conditioning patterns led to fatigue-free chronic stimulation. Muscles conditioned by multichannel stimulation exhibited between 20% and 33% less force than the contralateral unconditioned muscles, whereas in the single channel group this loss was between 32% and 43%. Thus, the multichannel method revealed relatively superior in preserving muscle force for chronic stimulation.     

Coarctation of the aorta: review of 362 operated patients. Long-term follow-up and assessment of prognostic variables

362 patients operated upon for coarctation of the aorta from1961–1980 were analyzed retrospectively. Age at operationwas <2 years in 74 (group A ) and 2 years in 288 patients(group B). Associated cardiovascular malformations were common,especially in group A patients. Early mortality was 12-2% forgroup A and 1-4% for group B patients. 336 patients were followedfor 6 months to 21 years (mean 8.9 years). Late mortality was0.8% per patient year. Associated cardiac defects and postoperativehypertension were responsible formost of the late deaths. Latereoperations were performed because of aortic valve disease,residual coarctation (with persistent hypertension) and aorticaneurysms at the site of anastomosis. The incidence of hypertensiondecreased from 82.5% preoperatively to 33.5% at discharge fromthe hospital. It decreased further during follow-up in patientsoperated <10 years of age, but remained constant in the olderpatients.In conclusion, morbidity and mortality after operativerepair of coarctation are determined mainly by (1) associatedcardiac malformations, and (2) postoperative hypertension. Patientswith isolated coarctation and postoperative normal blood pressurehave an excellent prognosis. Patients operated upon from between2–9 years of age carry the lowest risk for residual coarctationand late postoperative hypertension.     

Flow-Dependent Dilation and Myogenic Constriction Interact to Establish the Resistance of Skeletal Muscle Arterioles

Objective: To test the hypothesis that the diameter of skeletal muscle arterioles is determined by the interaction of responses elicited by intravascular pressure and flow. Methods: Experiments were conducted on isolated, cannulated, first-order arterioles of cremaster muscle of male Wistar rats. The diameter of arterioles was followed by videomicroscopy. Perfusion pressures and flows were controlled. Results: In the absence of perfusate flow, increases in perfusion pressure (from 0 to 120 mm Hg), after initial dilation, elicited endothelium independent constrictions of arterioles. At 60 mm Hg of perfusion pressure, the active diameter of vessels was 84.9 ± 1.9 μm. The passive diameter of arterioles (Ca²⁺-free solution) was 150.6 ± 2.4 μm. Increases in perfusate flow resulted in a significant upward shift in the pressure—diameter curves; in the presence of perfusate flows of 20, 40, and 60 μL/min, the constriction of the vessels at a pressure of 60 mm Hg was attenuated by 25.1 ± 3.9%, 35.2 ± 3.0%, and 46.8 ± 4.4%, respectively. In contrast, the corresponding diameter of arterioles at perfusate flows of 10 to 60 μL/min was significantly reduced when perfusion pressure was increased from 60 to 80 and 100 mm Hg (at a flow of 60 μL/min) by 12.0 ± 4.3% and 37.1 ± 2.8%, respectively. Hence, both flow- and shear stress—diameter curves were significantly shifted downward when perfusion pressure increased from 60 to 100 mm Hg. Conclusion: These results demonstrate that an interplay between pressure and flow-sensitive mechanisms is an important determinant of the arteriolar resistance in skeletal muscle.