Quantitative and qualitative morphologic, cytochemical, and ultrastructural characteristics of blood cells in captive Asian water monitors.

BACKGROUND: The Asian water monitor (Varanus salvator) is the most common monitor lizard in Thailand. Reported data regarding hematology and morphology of blood cells for this species are scarce. OBJECTIVES: The objective of this study was to assess routine hematologic variables and characterize the morphology, cytochemical staining, and ultrastructural features of blood cells in the Asian water monitor. METHODS: Blood samples from 55 monitors (22 males and 33 females) were obtained for a CBC. Cytochemical staining (Sudan black B [SBB], peroxidase [PO], α-naphthyl acetate esterase [ANAE], and beta-glucuronidase [BG]), and scanning and transmission electron microscopy were performed using standard methods. RESULTS: Determined mean (range) hematologic results of all monitors included PCV 0.32 L/L (0.20-0.44 L/L), HGB 106 g/L (62-157 g/L), WBC 15.9 × 10(9) /L (4.0-34.0 × 10(9) /L), heterophil 6.3 × 10(9) /L (1.5-17.1 × 10(9) /L, azurophil 2.6 × 10(9) /L (0.7-9.5 × 10(9) /L), basophil 0.1 (0.1-0.5 × 10(9) /L), lymphocyte 6.8 × 10(9) /L (0.5-13.1 × 10(9) /L), and monocyte 0.2 × 10(9) /L (0.04-1 × 10(9) /L) counts. Heterophils and basophils stained strongly positive with SBB, ANAE, and BG. Heterophils contained 2 types of granules, round SBB-positive and PO-negative granules, and electron-dense, large rod-shaped granules. Gamonts of Hepatozoon sp. were found in <1% RBC of 43 monitors. There was no significant difference between hematologic variables in Hepatozoon-positive and -negative monitors. CONCLUSION: Heterophils in Asian water monitors may also function as eosinophils based on cytochemical and ultrastructural features. The quantitative results may be used as base for further studies in healthy and diseased Asian water monitors.

[Microcirculation stream modeling: hydromechanic and acoustic models].

The objective was to attempt mathematical modeling of ultrasonic scanning tissue section in order to discern signals from erythrocytes and leucocytes that is displayed as Doppler images. Hydromechanic and acoustic microcirculation models have been constructed for a 20 MHz ultrasonic sensor. Results of the modeling showed that ultrasonic blood cells differentiation will require complex analysis of amplitude and frequency parameters of echoed signal.

Evaluation of the in vitro effect of a Lantana camara extract on the labeling of blood constituents of rats with technetium-99m.

Blood constituents labeled with technetium-99m (99mTc) have been used in nuclear medicine procedures and drugs are capable to interfere on this labeling. Lantana camara (lantana) has medicinal properties and it has been used in folk medicine. The aim is to verify the effect of a lantana extract on the labeling of blood constituents with 99mTc. Blood of rats was incubated with extract, stannous chloride and 99mTc, as sodium pertechnetate. Plasma (P) and blood cells (BC) were isolated, also precipitated with trichloroacetic acid and soluble (SF) and insoluble fractions (IF) were separated. The % of radioactivity (%ATI) in these samples was calculated. Samples of labeled BC were washed and the %ATI maintained (%ATI-M) in the BC was determined. The results showed that lantana extract decreased significantly (p < 0.05) in the IF-P from 70.24 +/- 2.59 to 11.95 +/- 3.07. This effect was not observed in the BC and IF-BC. The BC-%ATI-M was significantly (p < 0.05) decreased in all concentrations tested when the BC was washed. This fact was not observed in the control. Substances present on the extract should have redoxi action decreasing the concentration of the stannous ion and this condition could justify the effect on the IF-P. The results about the BC-%ATI-M should indicate a possible effect on the transport of ions through the erythrocyte membrane.

Acetylsalicylic acid decreases the labeling of blood constituents with technetium-99M.

Acetylsalicylic acid is the most widely used drug as antipyretic, analgesic, anti-inflammatory agent and for secondary prevention of thrombotic phenomena in the heart, brain and peripheral circulation. Drugs can modify the labeling of blood constituents with technetium-99m (99mTc). This work has evaluated the effect of in vivo treatment with acetylsalicylic acid on the in vitro labeling of the blood constituents with 99mTc. Wistar rats were treated with different doses (1.5, 3.0 and 6.0 mg/kg) of acetylsalicylic acid during 1 hour. At higher dose used (6.0 mg/kg) animals were treated during different period of time (0.25, 1.0 and 4.0 hours). Animals treated with physiologic saline solution were used as control. After the labeled process; plasma (P), blood cells (BC), insoluble (IF-P, IF-BC) and soluble (SF-P, SF-BC) fractions were separated. Afterwards, the percentage of radioactivity (%ATI) in each fraction was calculated. The treatment during 1 hour with acetylsalicylic acid at higher dose has significantly (p < 0.05) modified the fixation of 99mTc on blood cells. Considering the results, we suggest that acetylsalicylic acid used at therapeutic doses may interfere with the nuclear medicine procedures related to these blood constituents.

Pharmacokinetic study of darbepoetin alfa: absorption, distribution, and excretion after a single intravenous and subcutaneous administration to rats.

KRN321 is a hyperglycosylated analogue of recombinant human erythropoietin (rHuEPO, epoetin alfa), and its absorption, distribution, and excretion have been studied after a single intravenous and subcutaneous administration of 125I-KRN321 at a dose of 0.5 microg kg-1 to male rats. The half-lives of immunoreactive radioactivity in the terminal phase after intravenous and subcutaneous administration were 14.05 and 14.36 h, respectively, and the bioavailability rate after subcutaneous administration was 47%. The total radioactivity in tissues was lower than that in the serum in all tissues excluding the thyroid gland and skin at the injection site (subcutaneous administration). The maximum concentrations were observed in the bone marrow or skin at the injection site followed by the thyroid gland, kidneys, adrenal glands, spleen, lungs, stomach and bladder. The radioactivity found in trichloroacetic acid-precipitated fractions suggested that a high-molecular weight compound, unchanged or mixed with endogenous protein, distributed to the tissues after administration. The whole-body autoradiographic findings in both groups were in agreement with the tissue distribution mentioned above. The blood cell uptake of KRN321 was low for both groups. The excretion ratios of radioactivity into urine and faeces up to 168 h were 71.4 and 14.1% after the intravenous administration and 74.9 and 12.0% after the subcutaneous administration. There was no difference in the excretion profile of radioactivity between the two groups.

Ultrasonic characterization of proteins and blood cells.

Ultrasound changes its intensity and speed when propagating through a liquid or a suspension containing particles. In addition it generates a weak electric signal by altering the motion of ions and charged particles. Hence acoustic and electroacoustic measurements provide information about the properties of suspended particles and molecules. Here we present both acoustic and electroacoustic results on blood suspensions and protein solutions, relevant to life sciences. For blood cells a strong increase in acoustic attenuation with volume fraction is found, from which the speed of sound in an erythrocyte is found to be about 1900 m/s, assuming the attenuation is due to scattering only. A similar value of 1700 m/s is found from the increase in sound speed of the dispersion with concentration. Electroacoustic measurements on bovine serum albumin (BSA) yield a charge of about seven elementary charges per BSA molecule. These results show the power and usefulness of acoustic and electroacoustic measurement techniques for biological systems.

Bubble dynamics involved in ultrasonic imaging.

In clinical ultrasound, blood cells cannot be differentiated from surrounding tissue, due to the low acoustic impedance difference between blood cells and their surroundings. Resonant gas bubbles introduced in the bloodstream are ideal markers, if rapid dissolution can be prevented. Ultrasound contrast agents consist of microscopically small bubbles encapsulated by an elastic shell. These microbubbles oscillate upon ultrasound insonification. Microbubbles with thin lipid shells have demonstrated highly nonlinear behavior. To enhance diagnostic ultrasound imaging techniques and to explore therapeutic applications, these medical microbubbles have been modeled. Several detection techniques have been proposed to improve the detectability of the microbubbles. A new generation of contrast agents, with special targeting ligands attached to the shells, may assist the imaging of nonphysical properties of target tissue. Owing to microbubble-based contrast agents, ultrasound is becoming an even more important technique in clinical diagnostics.

A brief history of cell labelling.

The term cell labelling is usually used in the context of labelled leukocytes for imaging inflammation and labelled platelets for imaging thrombosis. Erythrocyte labelling for in vitro measurements of red cell life span, in vivo measurements of splenic red cell pooling, radionuclide ventriculography and imaging sites of bleeding has developed rather separately and has a different history. Labelled platelets and leukocytes were originally developed for cell kinetic studies. Since the current-day applications of labelled platelets and leukocytes depend on a clear understanding of cell kinetics, these classical studies are important and relevant to the history of cell labelling.

[Possibilities of microtomography of blood cells]. / Vozmozhnosti mikrotomografii kletok krovi.

Social reforms and the technological revolution lead to changes in the environment and human habitat, which deteriorate the ecology in the majority of cases. Blood system in general, specifically, the peripheral blood represent one most sensitive system of the body, reflecting the level of adverse exposures and reaction of the organism to these exposures. The interference microtomographer permits measurements of the spatial structure of optically transparent three-dimensional cytological specimens (blood cells). During preliminary studies a model of interference computer-aided microtomographer has been created and a method for treating preparations for processing by this microtomographer developed.

The effect of cyclosporine-A on labeling blood cells with radiopharmaceuticals.

The effect of cyclosporine-A (CsA) on the labeling efficiencies of red blood cells with reduced 99mTcO4-; leukocytes and platelets with 111In oxine was studied. Blood was used from rats treated with CsA (30 mg/kg body weight) for 28 consecutive days and from control rats. For 99mTc labeling of RBCs, blood was obtained from individual rats and in vitro labeling technique was used. For leukocyte and platelet labeling, blood was pooled from 5 rats either treated with CsA or control. Leukocytes/platelets were labeled with 111In oxine using routine techniques. The labeling efficiency for 99mTc RBCs was 83.42 +/- 0.83% (CsA treated) and 84.85 +/- 0.62% (control); 111In-oxine leukocytes was 38.5 +/- 1.75% (CsA treated) and 42.5 +/- 3.53% (control); and for 111In-oxine platelets, it was 74.0 +/- 2.5% (CsA treated) and 78.0 +/- 1.41% (control). Comparison of the results indicate that there is no difference between the percent labeling efficiencies of 99mTc RBCs, 111In-oxine leukocytes, and 111In-oxine platelets for CsA-treated and control rats. Hence, CsA does not interfere with the labeling process of blood cells with radiopharmaceuticals.

A new approach to labeling cells with technetium-99m, Part I. Preparation of modified polylysine and in vitro cell labeling.

A method for labeling cells with technetium-99m via hydrophilic, polycationic poly D-lysine modified by N-acetyl homocysteine has been developed. The modified polylysine (MPL) is labeled with 99mTc in > 95% yield and is stable for > 12 h. Maximum cell labeling is achieved by a 1-h incubation at room temperature with isolated leukocytes, granulocytes and peripheral blood mononuclear cells attaining 60-75% 99mTc incorporation, and red blood cells 35%. Ninety-two percent of the label is retained by leukocytes after a 1-h incubation at room temperature in 50% serum. The cell uptake of 99mTc-MPL is affected by the presence of negatively charged species in the medium; the inhibitory effects of 5% serum or serum albumin can be reversed by increasing the concentration of 99mTc-MPL, while those of heparin are not.

Modeling analysis of platinum-195m for targeting individual blood-borne cells in adjuvant radioimmunotherapy.

UNLABELLED: The inability to eradicate a population of single, isolated, blood-borne tumor cells with the radionuclides currently in use may limit the efficacy of adjuvant radioimmunotherapy. We have examined the possibility of sterilizing single blood-borne cells using surface-bound emitters of Auger and conversion electrons. METHODS: The number of cell-surface decays required for 99% sterilization was found by using the linear-quadratic model of cell survival (alpha = 0.3 Gy-1, alpha/beta = 10 Gy) to transform absorbed dose to survival probability. The absorbed dose to the center of the cell was calculated by evaluating the point dose kernel at the cell radius of 6 microns and multiplying it by the number of surface decays. A two-compartment model of whole-body pharmacokinetics was used to obtain the red marrow dose corresponding to a given number of cell-surface decays. RESULTS: Platinum-195m (T 1/2 = 4 days) proves to be a particularly effective radionuclide. The 195mPt protocol requires 1.2 GBq of injected activity and is calculated to give an average red-marrow dose of 1.23 Gy, well within marrow tolerance. CONCLUSION: Analysis of the targeting efficiency as a function of cell radius reveals that 195mPt is expected to sterilize cells with radii up to 8 microns without delivering more than 2.5 Gy to red marrow. It also emits photons that are appropriate for external imaging and has been used to study the biodistribution of cisplatin in humans. High-specific activity 195mPt may be obtained by decay of cyclotron-produced 195mIr (T 1/2 = 3.8 hr).

Blood cell labelling. Theory and methods: radiation hazards.

The chief physical properties of the radionuclide In111 are outlined, and compared with those of three other radionuclides, Tc99m, I131 and Cr51 which have similar applications. It is pointed out that the gamma-rays of In111 are appreciably more penetrating in lead than those of Tc99m and the significance of this, both in the use of shielding on syringes and in the effectiveness of lead glass screens is discussed. Examples are given of the dosimetry for In111 labelled cells in humans and it is noted that the absorbed dose in the spleen per mCi (37 MBq) injected may be some 10 rad (0.1 Gy). The problems that have been noted of damage to cells arising from oxine labelling and now considered to be due to radiation damage are briefly reviewed.

[The chemistry of indium complexes]. / Chemie der Indiumkomplexe.

There are no complexes of indium known to occur naturally in the human. Several radiopharmaceuticals labelled with In-111 or In-113m have been investigated for their application to localization studies. Most of the indium radiopharmaceuticals have a weak thermodynamic stability and, therefore, no specificity. It is known that such compounds are converted in vivo to In-labelled transferrin. Experiments to increase the thermodynamic stability, thereby leading to an increase in specificity have been followed up in two directions: Modification of polyaminocarboxylic acids (e.g. EDTA, DTPA) by reaction with a benzene diazonium salt or by substitution with methylene phosphoric acid instead of acetic acid in the EDTA molecule. Application of lipid soluble chelates of indium-111 for blood cell labelling (e.g. erythrocytes, leucocytes and platelets). The results are promising.

[Blood cell labeling: retrospective and prospects]. / Blutzellmarkierung: Rückblick und Ausblick.

The labelling of blood cells in vitro for subsequent in vivo studies was one of the earliest applications of radioactive tracers in clinical medicine and laid the foundations for many important contributions to the advancement of knowledge of human blood cell pathophysiology. The characteristics required for satisfactory clinical studies, the mechanisms of cell labelling, the problems of radiation of chemical damage to the labelled cells and some examples of modern clinical applications are described and discussed.

Blood cell labelling techniques: state of the art.

A critical survey has been given of recent developments in the technique of cell labelling. The ideal characteristics of the radionuclide, as well as the complexing substance, carrying the nuclide inside the cell are formulated. The importance of limiting the radiation dose, cellular radiosensitivity, as well as the quality control of the final cellular suspension are emphasized.