Study on medicinal chemistry of K203 in wistar rats and beagle dogs.

K203 is an experimental bis-pyridinium mono-aldoxime type cholinesterase reactivator of potential use in organophosphate/ organophosphonate poisoning. Pharmacokinetics of K203 were examined in Wistar rats and beagle dogs using ion-pair HPLC. Serum and cerebrospinal fluid concentrations of K203 were determined using ion-pair reversedphase chromatography on octadecyl silica column. HPLC with ultraviolet detection was used for determination of serum concentration of K203 higher than 0.1 µg/mL while its low concentrations in cerebrospinal fluid required electrochemical detection (0.015 through 4 µg/mL range). In rats the serum levels of K203 followed zero order pharmacokinetics from 15 to 120 minutes post administration. Zero order pharmacokinetics was also observed in beagle dogs after low dose (15 µmol/kg) of K203 administration. High dose administration (250 µmol/kg) led to subsequent hindered elimination from both cerebrospinal fluid and serum.

Effect of anticoagulants and sampling time on results of progesterone determination in canine blood samples.

The concentration of plasma progesterone was measured by ELISA, in serum and samples prepared with three different anticoagulant agents - namely ethylenediaminetetraacetic acid (EDTA), heparine and sodium fluoride oxalate potassium(NaFK). Forty clinically healthy bitches were selected based on the signs of pro-oestrus or oestrus. Values of progesterone concentration were significantly higher in serum than in EDTA-plasma (p < 0.0005); heparin-plasma (p < 0.05) and NaFK-plasma (p < 0.005). During pro-oestrus and oestrus until the time of ovulation, progesterone exhibited a conspicuous and statistically verified diurnal pattern (p < 0.05), its serum concentration being higher during 6.00-7.00 p.m. than 8.00-9.00 a.m. By the time of ovulation tendency of higher p.m. progesterone level reverses and from this point on the a.m. progesterone concentration is higher. The results of these experiments indicate that the concentration of canine progesterone assayed with ELISA may be affected by the time of collection and the method of preservation used.

Sentinel lymph node detection with large human serum albumin colloid particles in breast cancer.

Detection of metastatic involvement of lymph nodes is essential for management and prognostic evaluation in breast cancer patients. The success of lymphatic mapping depends on identifying the sentinel lymph node(s) draining the primary tumour. However, when mapping is performed with a radiocolloidal agent, the number of hot lymph nodes varies with the agent and its size, among other factors. In this study, we evaluated prospectively the detection rate of sentinel lymph nodes in breast cancer when injecting large particles (100-600 nm) of human serum albumin colloids (Senti-Scint). In 128 consecutive breast cancer patients without palpable lymph nodes, pre-operative static lymphoscintigraphic mapping of the breast was performed after subcutaneous injection of 15 MBq of the radiocolloid. Lymphoscintigrahic results were compared with intra-operative surgical gamma detection probe and blue dye mapping data. Pre-operative lymphoscintigraphy and surgical gamma detection probe both correctly detected 203 sentinel lymph nodes in 122/128 patients (95%), while blue dye mapping showed only 183 sentinel lymph nodes in 82% of the patients. Only one or two sentinel lymph nodes were identified in each patient, which allowed the surgeon easily to find the sentinel lymph node(s) intra-operatively. In conclusion, lymphoscintigraphy with large particles of human serum albumin colloids is a helpful and reliable procedure for the surgical management of breast cancer.

Oncological scintigraphy in dogs with 99mTechnetium MIBI and DMSA(V)--two case reports.

Oncological scintigraphy is described in two dogs with malignant lymphoma and malignant schwannoma, respectively. The distribution of the radiopharmaceuticals could be visualized for the purpose of detection of neoplasia and eventual metastases, and to evaluate the effectivity of therapy. It is concluded that 99mTechnetium MIBI and 99mTc DMSA (V) scintigraphy is useful for the detection of soft tissue malignancy in dogs.

Diagnostic sensitivity of three tumour markers in non-small cell lung cancer: a pilot study.

BACKGROUND: Three tumour markers (CEA, CYFRA 21.1 and CA125) were evaluated for diagnostic sensitivity in newly diagnosed, untreated non-small cell lung cancer. METHODS: In the 24 patients studied, the tumours were classified histologically as 15 squamous cell carcinomas and 9 adenocarcinomas. In 19 cases, the disease was confined to the lung (M0); 5 cases presented with metastatic disease at the time of diagnosis (M1). RESULTS: CA125 displayed the best overall sensitivity (62%) and also when only localised disease was evaluated (63%). CA125 was the most sensitive marker for adenocarcinomas (89%), with values differing significantly with histological type (p < 0.005). CYFRA 21.1 was most sensitive in squamous cell carcinomas (53%); this was the only marker which was elevated in all cases involving metastatic disease, and exhibited a significant correlation with stage (p<0.02). CEA presented the poorest overall sensitivity (42%). The overall sensitivity of the three-tumour marker association was 79% and the best combination of two markers was CYFRA 21.1 + CA125 (75%). CONCLUSIONS: This pilot study allows recommendation of the associated use of these two markers as first choice of diagnostic aid in non-small cell lung cancer. Further measurements, including specificity studies in benign lung diseases, should be performed to confirm these results.

[Evaluation of the nature of brain tumors using methods of nuclear medicine]. / Agydaganatok természetének vizsgálata nukleáris medicinai módszerekkel.

FDG-PET studies permit an assessment of the degree of brain tumour malignancy and detection of tumour recurrence. MIBI-SPECT also affords promising results in this respect. In this work, the diagnostic value of MIBI-SPECT was compared with that of FDG-PET for the determination of primary brain tumours malignancy and the detection of recurrent brain tumours. SPECT and PET examination were carried out within a week in 14 patients (12 males, 2 females, mean age: 40 years, range 16-61 years) with brain tumours. Seven patients had a primary tumour, and in a further 7 MRI or the clinical signs and symptoms let to a suspicion of tumour recurrence. All tumours were verified histologically to be gliomas of grades I-IV. The SPECT and PET images were analysed visually and semiquantitatively. In 3 of the investigated 7 primary glioma patients, there was a visibly enhanced MIBI-positive cases, only one had an increased FDG uptake. In 4 of the 7 tumour recurrence cases, either the MIBI or the FDG uptake was visibly increased. All of these were histologically high-grade gliomas. In the remaining low grade tumours (primary of recurrent), neither MIBI nor FDG revealed a pathologically increased uptake. The intensity of radiopharmaceutical uptake at the site of the tumours was visually and semiquantitatively higher for MIBI that for FDG. It is concluded that MIBI-SPECT is a valuable and simple tool for evaluation of the biological characteristics of brain tumours, showing increased uptake of MIBI according to the malignancy and tumour recurrence of brain tumours.

Thyroid volumetric measurement and quantitative thyroid scintigraphy in dogs.

Thyroid volumetric measurement combined with quantitative 99mTc-per-technetate thyroid scintigraphy was performed in 62 clinical canine patients having suspected thyroid abnormalities. Euthyroid dogs (n = 22) had a total thyroid size of 3.60 +/- 1.36 cm3, the thyroid/salivary gland region of interest (ROI) ratio was 2.01 +/- 0.55, the thyroid/background ROI ratio was 3.86 +/- 0.90, and 20-min thyroid radioactivity uptake was 1.17 +/- 0.71% of the injected dose (I. D.). By Student's unpaired test, thyroid size of the hypothyroid group (n = 36) was not statistically different from that of the euthyroid dogs, but all other quantitative data (e.g., thyroid/salivary gland ROI ratio = 1.08 +/- 0.56, thyroid/background ROI ratio = 2.32 +/- 0.70, and 20-min thyroid radioactivity uptake = 0.34 +/- 0.22% of the I. D.) were significantly (p < 0.001) lower in hypothyroid than in euthyroid dogs. Evaluating the above-listed quantitative data of separated thyroid lobes by Student's paired test, there was no significant difference between the left and the right lobe either in the euthyroid or in the hypothyroid group.

Diagnosis of hyperadrenocorticism in dogs as compared to human diagnostic methods: a review.

Spontaneous hyperadrenocorticism is a common and well-recognised endocrine disorder occurring in dogs. The biochemical diagnosis of hyperadrenocorticism rests on the documentation of excessive glucocorticoid levels or metabolites in urine or blood. The diagnosis of canine hyperadrenocorticism is historically developed from human methods and based on non-dynamic and dynamic tests and visualisation. In some cases the different ranges of endocrine parameters or metabolites necessitate the modification of human protocols. Elevation of the activity of alkaline phosphatase (AP) and its heat-resistant isoenzyme (SIAP) induced by endogenous or exogenous glucocorticoid excess raise the suspicion of hyperadrenocorticism. Cortisol values in morning urine are related to creatinine concentrations to correct for differences in urine concentration. Theoretically, the administration of dexamethasone (DX) at a relatively low dose (0.01 mg/kg of body weight) can inhibit the pituitary secretion of ACTH and, in turn, decrease endogenous cortisol secretion for as long as 24 to 48 h. Therefore, DX administration to dogs with a functioning adrenocortical tumour would not affect the plasma cortisol concentration at any time following its administration. The high-dose dexamethasone suppression test (HDDS) is based on the observation that the function of adrenocortical tumours is independent of pituitary ACTH and they completely suppress ACTH secretion; therefore, regardless of its dose, dexamethasone is never able to suppress cortisol secretion. HDDS can be combined with the measurement of urinary cortisol/creatinine (c/c) ratio from morning urine samples on three consecutive days. In case of non-suppressible urinary c/c ratio one has to speculate on differentiating adrenal tumour (AT) from non-suppressible pituitary-dependent hyperadrenocorticism (PDH) due to a pituitary tumour arising from the intermediate lobe. Radiocholesterol scintigraphy is a less frequently used technique in the diagnosis of canine Cushing's syndrome (CCS); however, it has the same advantages in the localisation and characterisation of adrenocortical diseases as in humans.

Clinical renal allograft transplantation in a Dalmatian dog: case report.

A case of successful renal allograft transplantation performed in a two-year-old female Dalmatian dog suffering from end-stage chronic renal failure is reported. A one-year-old male German shepherd with severely injured spinal cord was used as kidney donor. Simultaneous kidney allograft transplantation combined with hypothermic initial perfusion as graft conservation was done, placing the donor kidney into the right iliac fossa of the recipient. The immunosuppression protocol consisted of prednisolone and azathioprine. Regular physical, laboratory, ultrasonographic and scintigraphic examinations were used for assessing both the morphology and the function of the allograft. After a two-week period of hospitalisation the patient was discharged in a remarkably improving condition. The recipient died on postoperative day 45 of respiratory insufficiency resulting from secondary pneumonia and pulmonary oedema. Neither macroscopic nor microscopic abnormalities of the allograft were revealed by necropsy.

[Evaluation of a complex trace element composition and bioutilization using isotope technics and total body measurement]. / Komplex nyomelem készítmény biológiai hasznosulásának tanulmányozása izotópos nyomjelzéstechnika és egésztest-mérés alkalmazásával.

Modified mineral and trace element solutions were prepared containing Zn-65, Co-57, Mn-54, Fe-59, Mo-99 and Ni-63 isotopes which were physico-chemically identical to the original solution. Bioutilization examinations were carried out on animals receiving their normal feeding, after p. os application of complex trace element composition (CTEC) namely whole-body retention studies, bioassays, scintigraphic and excretion examinations in altogether 180 Wistar rats, 6 Beagle and 2 mongrel dogs using whole body counter, gamma and beta counters, gamma camera and metabolic cages. Extremely high whole body retention was measured in case of iron (8-30%), high utilizations in case of zinc (4-5%), cobalt (4-6%), molybdenum (3-4%) and manganese (2-4%) and a lower value in case of nickel. Bioassay and scintigraphic evaluations showed marked liver-, kidney-, and muscle and moderated blood uptakes. The way of excretion was mainly (more than 90%) via the faeces in case of zinc, manganese, iron and nickel, although cobalt excreted in 8% and molybdenum in 52% via the urinary tract. Our results show, that isotope technique combined with whole body counting and excretion studies in an available method for trace element bioutilization studies.

Principles of renal transplantation in the dog: A review.

The practically relevant body of knowledge available on renal transplantation in the dog is reviewed. A review of the history of renal transplantation is followed by a detailed description of the immunological fundamentals of transplantation, with especial regard to the structures directing rejection, the significance of D-LA-typing and the MLR test serving for their determination, and the possible methods of nonspecific and specific immunosuppression. The most important criteria of recipient and donor selection are presented, together with the main aspects and medicinal protocol of prednisolone-azathioprine and prednisolone-cyclosporin A immunosuppression within the framework of preparation for the surgical intervention. Among the surgical aspects of renal transplantation, first the recommended anaesthetic techniques are outlined, then the three stages of the surgical procedure, i.e. donor nephrectomy, renal perfusion and renal grafting, are described in detail. The last chapter of the article presents the physical, laboratory and instrumental diagnostic methods of rejection diagnosis, with special regard to their practical importance and different roles played in signalling the rejection.

Experience with the iodine-123 and technetium-99m labelled anti-granulocyte antibody MAb47: a comparison of labelling methods.

Four different methods of radiolabelling the anti-granulocyte monoclonal antibody MAb47 were compared and their influence on diagnostic value studied. The best clinical images were obtained following labelling with iodine-123 by the Iodogen method and direct labelling with technetium-99m after tris-(carboxyethyl)-phosphine treatment of MAb47 to achieve disulphide bridge reduction. 99mTc labelling using a specific ligand (MAb47-mtp), or a second method involving direct reduction with mercaptoethanol, led to an increased background activity in clinical studies, thus impeding the diagnosis of chronic disease. Fresh infections were clearly localized by all four preparations. The elimination of the activity from the blood was slower in the case of the iodinated MAb47, while the collected urine samples showed an excretion of about 10% of the injected activity per day independent of the labelling method. The results in terms of sensitivity and specificity were rather similar for all labelling methods and ranged from 90% to 99%.

In vitro and in vivo motility studies of 99mTc HM-PAO labelled sperm cells.

The motility of 99mTc HM-PAO radiolabelled sperm cells, labelled as described previously (Balogh et al., 1992) was studied. The active migration of spermatozoa was demonstrated in capillary tubes containing bovine oestrous mucus, using an in vitro motility analyzer. Like nonlabelled sperm cells, the labelled spermatozoa covered a 4-5 cm distance in the capillary tubes during a 10-min run. In vitro motility testing of labelled spermatozoa from different animal species (cattle, rabbit, sheep, horse) did not reveal significant differences. The distribution of spermatozoa within the female genital tract was studied in a previously described animal model (rabbit) and in two new models (sheep, chicken). This method enables the determination and visualization of sperm distribution by a noninvasive technique. The results of in vivo motility tests pave the way for the introduction of a method of unprecedented specificity, which serves for studying the penetrability of the oviduct to spermatozoa.

In vivo metabolism of the technetium isonitrile complex [Tc(2-ethoxy-2-methyl-1-isocyanopropane)6]+.

Technetium(2-ethoxy-2-methyl-1-isocyanopropane)6+, [Tc-EIBT] is a complex of technetium(I) structurally similar but slightly more lipophilic than the commercial myocardial perfusion agent Cardiolite [Tc-MIBI]. Tc-EIBI exhibits rapid extraction from the blood into heart, liver, kidney and striated muscle and rapid hepatobiliary clearance. In the guinea pig, unlike Tc-MIBI, this compound is almost completely enzymatically metabolized to numerous cationic complexes containing a mixture of ethyl other and hydroxy isonitrile ligands. Substitution of the ethyl other group for a methyl ether produces an agent that shows selective in vivo metabolism and more rapid clearance from the liver.

Pharmacokinetics of radiopharmaceuticals.

The pharmacokinetics of various radiopharmaceuticals following i.v. administration in mice and rats has been studied and compared. Before injection the radiochemical purity (RP) of the compounds were determined by HPLC and PAGE. In all cases RP-s were higher than 90%. The biodistribution of 99mTc labelled anti CEA IgG was studied in mice bearing human colon carcinoma xenografts. Animals with different tumour weights showed different blood kinetic and tumor uptake. The pilot clinical study of the 99mTc labelled anti melanoma Fab and 111-In-DTPA labelled anti melanoma F(ab')2 showed differences in the pharmacokinetic parameters. (99mTc labelled: comp.A. 84.6%; T1/2:0.6 h, 111-In-labelled: comp.A.: 46%, T1/2 1.5 h.) The various isonitrile derivatives synthetized in our laboratory were labelled with 99mTc and the biodistribution were tested in rats. The kinetic study showed that all the three molecules have different half lives in the heart and liver (T1/2 for heart ranged 5.1-18.6 h, for liver T1/2:1.2-2.5 h). Reversed phase HPLC study of the collected bile showed the 15-100% of injected compounds are metabolized during hepatic excretion. Literature data and our recent observations confirm that the knowledge of pharmacokinetics of radiolabelled compounds both in research, development and clinical practice is of basic importance.

Radioimmunoassay of thyrotropin-releasing hormone in euthyroid subjects and in patients with thyroid diseases.

An episodic pattern of fluctuation in serum TRH level was demonstrated in euthyroid males. It is suggested that these rises in serum TRH-IR are due to its pulsatile hypothalamic release, however, it must be remembered that a high proportion of circulating TRH is derived from extrahypothalamic sources. The conception that the TSH surge during late evening is secondary to an increased TRH release could not be proved in the present study. In the euthyroid and primary hypothyroid groups the mean values of serum TRH-IR did not differ, while its level was slightly, but not significantly lower in hyperthyroid patients. The evaluation of a single TRH determination is impeded by the short half-life, low serum level and its production in extrahypothalamic sites, too.

Binding of fibronectin to human lipoproteins.

High molecular mass adhesive glycoprotein plasma fibronectin binds to isolated HDL and LDL lipoprotein fractions in a solid phase radioimmunoassay. Mean dissociation constants of interaction of fibronectin and immobilized HDL and LDL lipoproteins isolated from eight patients with type IIa and type IV hyperlipoproteinemia are 7.8 +/- 3.2 X 10(-7) mol/l and 6.8 +/- 2.6 X 10(-7) mol/l, respectively. Fibronectin can also bind to HDL and LDL isolated from six healthy subjects with mean dissociation constants of 2.07 +/- 0.45 X 10(-6) mol/l and 2.25 +/- 0.48 X 10(-6) mol/l, respectively. The binding is not dependent on the presence of divalent cations. Fibronectin-lipoprotein interaction is inhibited by soluble lipoproteins. There is no observable interaction between fibronectin and VLDL fraction. Binding of fibronectin to HDL and LDL lipoproteins can have an in vivo significance, since the interaction may play a role in the metabolism, deposition of lipoproteins into the vessel wall and in atherogenesis.

The use of electroimmunoassay for the determination of the in vivo stability of labelled proteins.

The in vivo stability of 125I, 99Tcm and 67Ga labelled HSA was measured by electroimmunoassay (EIA). Radiolabelled HSA compounds were intravenously injected into rabbits, and blood samples were taken 2, 5, 10, 30 and 60 min after injection. The activity and HSA content of rabbit sera were measured simultaneously. The results showed that HSA had been eliminated from the bloodstream at the same rate in all three cases (95-97% of HSA were in the circulation). Significant differences in the activity of serum samples are unequivocally due to differences in labelling and type of binding. Metal isotope detachment values were: 99Tcm-HSA, 47.3%; 67Ga-DF-HSA, 20.8% and 125I-HSA, 11.4% The data demonstrate that EIA may be a suitable method for the determination of the serum stability of protein-based radiopharmaceuticals.