Organ retrieval in donors suspected of cancer: single-center experience.

BACKGROUND: The transmission of cancerous cells with a transplanted organ is among the most serious complications of transplant surgery. Detailed preoperative tests seek to reduce the risk of transmission of viral and bacterial infections as well as to prevent donor-derived malignancy following organ transplantation. The objective of this study was to report our experience among cadaveric donors who we suspected of cancer. MATERIALS AND METHODS: We performed a retrospective search of the medical records of 75 potential cadaveric donors referred to our unit between January 2007 and December 2010. Our focus, however, was on donors suspected of cancer. RESULTS: Among 75 potential cadaveric donors 22 (29%) revealed features suggestive of cancer: physical signs of tumor pre- or intraoperatively: elevation of serum levels of a cancer marker; or an abnormal finding on radiological imaging. Among the latter group, 15 donors necessitated urgent histopathologic examination to rule out or confirm cancer. In four cases, organ transplantation was abandoned following the examination, including three cases in which a tissue diagnosis of cancer was evident and in one case, the examination was inconclusive to exclude cancer. In the remaining 14 cases, the histopathologic examination did not reveal cancer; thus transplantation was performed. CONCLUSIONS: Thorough histopathologic examination is essential in all potential donors who are suspected of cancer to prevent donor-derived malignancy following transplantation. In some cases, however, the tissue sampling is not conclusive; hence, transplantation must be abandoned. Even the most precise examination of the donor does not protect the recipient from the risk of transmission of cancer.

Successful kidney transplantation in a patient with multiple endocrine neoplasia type 2A syndrome: case study.

We present the case of a 37-year-old patient diagnosed with multiple endocrine neoplasia type 2A (MEN 2A) syndrome, as confirmed by genetic tests, who underwent the transplantation of a kidney from a cadaveric donor. MEN 2A, a hereditary autosomal dominant syndrome, is caused by the mutation of the RET proto-oncogene. In almost all patients this syndrome, is characterized by the occurrence of medullary thyroid cancer and pheochromocytoma; in some individuals also hyperparathyroidism. The available literature has not documented a kidney transplantation performed in Poland for this indication.

GABA content and GAD activity in gastric cancer.

BACKGROUND: Several recent reports have suggested a connection between the GABA-ergic system and neoplastic processes. It has been confirmed that both GABA content and GAD activity, are increased in neoplastic tissues in colon and breast cancer. In the light of the theory of dynamic balance between stimulating and inhibitory amino acids, disturbances in GABA metabolism may be an expression of the cell's defensive response to the neoplastic process. The aim of the present study was to evaluate GABA content and GAD activity in the tissue from gastric cancer and in the macroscopically unchanged wall of the stomach. MATERIAL AND METHODS: GABA content and GAD activity were evaluated in tissue material obtained from 34 patients operated for gastric cancer. GABA and GAD levels were determined in neoplastic tissue and surrounding unchanged tissue by spectrofluorometric method. RESULTS: The investigations revealed that the GABA content and GAD activity were significantly higher in the neoplastic tissue in comparison to the unchanged tissue of the stomach. CONCLUSION: The results obtained, together with reports from the literature, suggest the possibility of introducing GABA-ergic system agonists into adjuvant therapy in gastric cancer.

Binding and functional potency of neurokinin A analogues in the rat fundus: A structure-activity study.

Structure-activity relationships of neurokinin A (NKA) and the two analogues NKA(4-10) and [Nle10]NKA(4-10) were investigated at the rat fundus NK-2 receptor, using selected amino acid substitutions. Both radioligand binding with [125I][Lys5,Tyr(I2)7,MeLeu9, Nle10] NKA(4-10) and functional studies were performed and correlated. In membrane binding experiments loss of His1 and Lys2, or replacement of Lys2 with Ala did not substantially alter binding affinity of NKA. NKA(4-10) free acid was unable to compete with the radioligand. [Nle10]NKA(4-10) binding affinity to rat fundus membrane preparations was decreased when substituting Asp4 with Gln or Asn, or Val7 with either Tyr or Ile. Replacement of Ser5 with the negatively charged Glu also decreased the binding affinity, but substitution with the positively charged Lys substantially increased the affinity of [Nle10] NKA(4-10) for the NK-2 receptor. Lengthening NKA(4-10) or [Nle10]NKA(4-10) with Ala11 or Nle11, respectively, decreased the binding affinity of the peptide. In both binding and functional studies, replacement of any of the residues of NKA(4-10), except for Ser5, with alanine decreased the affinity of the peptide for the NK-2 receptor. Ala substitutions at positions 4, 6, and very obviously at 8, 9 and 10 of NKA(4-10) yielded peptides unable to achieve a maximum contractile response, although they did not demonstrate antagonist activity. These data confirm the importance of the NKA carboxyl terminus, and the requirement for Phe6, Val7, Gly8, Leu9 and Met10 integrity for interaction with the NK-2 receptor. They also suggest that Ser5 is a good site to target modifications leading to the design of new potential drugs.

An investigation of tachykinin NK2 receptor subtypes in the rat.

The heterogeneity of tachykinin NK2 receptor subtypes was examined in five tissues from the rat, using binding and functional techniques. Initial experiments with the selective radioligand [125I][Lys5,Tyr(I2)7,MeLeu9,Nle10]neurokinin A-(4-10) showed no specific binding to rat spinal cord membranes or sections. However, this radioligand exhibited high specific binding (80-95% of total) in membranes from the rat fundus, colon, bladder and vas deferens. Dissociation constants (KD) were lower in bladder and colon (0.4 nM) than in fundus (1.9 nM) or vas deferens (1.4 nM). Neurokinin A, neuropeptide gamma, [Lys5,MeLeu9,Nle10]NK(4-10), SR 48968 [(S)-N-methyl-N[4-(4-acetylamino-4-phenylpiperidino)-2-(3,4-dichlorophen yl)butyl]benzamine], GR 94800 [PhCO-Ala-Ala-DTrp-Phe-DPro-Pro-Nle-NH2] and MEN 10627 [cyclo(Met-Asp-Trp-Phe-Dap-Leu)cyclo(2beta-5beta)] displayed high affinity (pIC50 8.4-9.5) as competitors, with no significant difference in potency between these four tissues. [Lys5,MeLeu9,Nle10]neurokinin A-(4-10) contracted the isolated fundus (EC50 117 nM) and bladder (EC50 10 nM) and these responses were similarly inhibited by the tachykinin NK2 receptor antagonists, SR 48968 and MEN 10627 (pA2 values 7.6-8.2). In spite of differences in KD seen in some tissues, these results do not provide compelling evidence for tachykinin NK2 receptor heterogeneity in smooth muscle-containing tissues in the rat. The absence of detectable binding in rat spinal cord may be due to very low expression of tachykinin NK2 receptors, or to existence of a different receptor subtype.

GABA content and GAD activity in colon tumors taken from patients with colon cancer or from xenografted human colon cancer cells growing as s.c. tumors in athymic nu/nu mice.

A significantly high GABA level and GAD activity was found in human colon cancer tissue as compared with normal macroscopically unchanged human colon wall taken from the same patients. Similarly in athymic nu/nu mice transplanted with human colon adenocarcinoma cells established in in vitro culture (line CX-2) the high level of GABA accompanied by high GAD activity was found in subcutaneously growing tumors as compared with the unchanged colon wall and unchanged skin tissue from the same tumor bearing mice. Interestingly, the level of GAD activity in the macroscopically unchanged colon tissue of mice transplanted with tumor cells were increased in comparison with normal colon of healthy control mice. For the skin, only GAD activity was higher in the material coming from tumor bearing mice than in the material from normal control mice, whereas GABA level was even lower in the skin of tumor inoculated mice compared with control group. An increase in GABA level and in GAD activity can perhaps reflect a local immune response to the neoplastic process. The observed direction of GABA metabolism in tumor of the colon indicates a possibility to interfere in this process using the agonists of the GABA-ergic system.

The antipyretic activity of adenosine agonists.

1. Thermoregulatory reactions after IV administration of A1 [N6-cyclohexyladenosine (CHA); 0.15 mg/kg] and A2 [5'-N-ethylcarboxamidoadenosine (NECA); 0.15 mg/kg] receptor agonists were investigated in pyrogen-treated rabbits (lipopolysaccharide; 1 microgram/kg IV) at an ambient temperature of 20 +/- 1 degrees C. 2. Both compounds produced antipyresis, which was accompanied by inhibition of metabolic rate. NECA, additionally, reversed the inhibitory effect of pyrogen on respiratory rate. 3. Neither CHA nor NECA affected postpyrogen drops in ear skin temperature. 4. The mechanisms underlying the antipyretic action of the compounds in question are discussed.

The effect of N6-cyclohexyladenosine and 5'-N-ethylcarboxamidoadenosine on body temperature in normothermic rabbits.

1. Thermal responses to i.v. administration of N6-cyclohexyladenosine (CHA; 0.15 mg/kg), A1 adenosine receptor agonist, or 5'-N-ethylcarboxamidoadenosine (NECA; 0.15 mg/kg), A2 adenosine receptor agonist, were investigated in normothermic rabbits at an ambient temperature (Ta) of 20.0 +/- 1.0 degrees C. 2. Although both compounds inhibited metabolic heat production, only NECA produced hypothermia. 3. NECA showed strong hypotensive activity. 4. Both compounds produced vasoconstriction of the ear skin vessels and CHA, in addition, slowed down the respiratory rate. 5. The role of A1 or A2 adenosine receptors in the thermoregulatory activity of these compounds is discussed.

Do sodium nitroprusside and L-NAME affect pyrogen fever in rabbits?

Thermoregulatory responses after treatment with nitric oxide (NO) donor, sodium nitroprusside (SNP-3 mg/kg/h), or NO synthase inhibitor, NG-nitro-L-arginine methylester (L-NAME-100 mg/kg) were investigated in febrile rabbits (lipopolysaccharide E. coli-1 meg/kg). Pretreatment with SNP attenuated pyrogen fever as well as metabolic rate. L-NAME also inhibited postpyrogen increases in metabolism; however, this effect did not lead to antipyresis.

Thermoregulatory activity of sodium nitroprusside and arginine vasopressin.

1. Thermal responses to sodium nitroprusside (SNP, 3 mg/kg/hr) and arginine vasopressin (AVP, 3 micrograms/kg) were investigated in normothermic and febrile rabbits (LPS, 1 microgram/kg) at ambient temperature of 20.0 +/- 1.0 degrees C. Furthermore, blood pressure after these drugs was tested on a separate group of animals. 2. I.v. infusion of SNP produced hypothermia and attenuated pyrogen fever. On the other hand, AVP increased body temperature and intensified the febrile response. 3. Both drugs affected in an opposite way blood pressure, i.e. SNP produced falls and AVP increases in this parameter. 4. The relationship between the activity of the vascular and thermoregulatory systems in normothermic or febrile state is discussed.

Some enzymic activities of two Australian ant venoms: a jumper ant Myrmecia pilosula and a bulldog ant Myrmecia pyriformis.

Venoms from two related Australian ants, a jumper ant (Myrmecia pilosula) and a bulldog ant (Myrmecia pyriformis), were quantitatively analysed for the following enzymic activities: phospholipase A2, phospholipase B, phospholipase C, hyaluronidase, esterase, acid phosphatase, alkaline phosphatase and phosphodiesterase. Both venoms contained phospholipase A2, phospholipase B, hyaluronidase, acid phosphatase and alkaline phosphatase activities. Myrmecia pyriformis venom had significantly greater phospholipase B, acid phosphatase and alkaline phosphatase activities than Myrmecia pilosula venom. No detectable quantities of phospholipase C, esterase or phosphodiesterase activities were found in either venom.

Pharmacological studies of the venom of an Australian bulldog ant (Myrmecia pyriformis).

The purpose of this study was to examine some of the pharmacological actions of venom from the Australian bulldog ant Myrmecia pyriformis. M. pyriformis venom was prepared by extraction of venom sacs in distilled water and centrifugation to remove insoluble material. Venom (2 micrograms/ml) produced a biphasic response of isolated guinea-pig ileum, i.e., an initial rapid contraction followed by a slower prolonged contraction. The histamine antagonist mepyramine (0.1 microM) inhibited the first phase of this response by approximately 80%. In the isolated rat stomach fundus strip (histamine-insensitive), venom (2-4 micrograms/ml) produced only a single contraction. Responses to venom of egg-albumin-sensitized guinea-pig ileum, were not significantly different before and after an anaphylactic response induced in vitro by egg albumin (0.5 mg/ml). Fluorometric assay showed that histamine accounted for 3.5 +/- 0.5% of the dry weight of M. pyriformis venom. Both the lipoxygenase/cyclooxygenase inhibitor BW755C and the cyclooxygenase inhibitor indomethacin significantly inhibited the response to venom of guinea-pig ileum (second phase) and rat fundus strip. M. pyriformis venom caused hemolysis of guinea pig blood. The degree of hemolysis was reduced significantly when boiled venom was used. No evidence was found that the venom contains acetylcholine, bradykinin, or 5-hydroxytryptamine or that the venom releases histamine from guinea-pig ileum. However, the results indicate that the venom contains histamine-like activity. In addition the venom was found to cause the release of cyclooxygenase products and to contain a heat-sensitive hemolytic factor.

Hypotensive drugs, sodium nitroprusside and prazosin inhibit the metabolic rate in rabbits.

1. Thermoregulatory responses (metabolic rate, rectal and ear skin temperatures, respiratory rate) were measured after treatment with two antihypertensive drugs, i.e. when sodium nitroprusside (6 mg/kg/2 hr) or prazosin (0.75 mg/kg/3 hr) were applied to normothermic or febrile rabbits under thermoneutral conditions (19 +/- 1 degree C). 2. Both drugs significantly decreased blood pressure and metabolic rate. 3. These changes were accompanied by antipyresis. 4. In the case of normothermic rabbits only sodium nitroprusside produced prominent falls in body temperature. 5. The relationship between changes in blood pressure and the intensity of metabolic rate is discussed.

Pharmacological studies of jumper ant (Myrmecia pilosula) venom: evidence for the presence of histamine, and haemolytic and eicosanoid-releasing factors.

Jumper ant venom was prepared by extraction of venom sacs in distilled water and centrifugation to remove insoluble material. Jumper ant venom (2 micrograms/ml) produced a biphasic response on isolated guinea-pig ileum, i.e. an initial rapid contraction followed by a slower prolonged contraction. The histamine antagonist mepyramine (0.1 microM) inhibited the first phase of this response by greater than 90%. In the isolated rat stomach fundus strip (which is insensitive to histamine), jumper ant venom (6 micrograms/ml) produced only a single contraction. No tachyphylaxis was observed to repeated doses of jumper ant venom in guinea-pig ileum or rat fundus strip. Responses to jumper ant venom of the egg-albumin-sensitised guinea-pig ileum were not significantly different before and after an in vitro anaphylactic response induced by egg albumin (0.5 mg/ml). Fluorometric assay revealed a mean value of 0.9 +/- 0.2% of the dry weight as histamine in jumper ant venom. Both the lipoxygenase/cyclo-oxygenase inhibitor BW755C and the cyclooxygenase inhibitor indomethacin significantly inhibited the second phase response to jumper ant venom of the guinea-pig ileum, and the response of the rat fundus strip. The muscarinic receptor antagonist atropine (0.1 microM), the bradykinin antagonist [Thi5,8,D-Phe7]-bradykinin (10 microM) and the angiotensin converting enzyme inhibitor captopril (20 microM) did not affect either phase of the venom response in guinea-pig ileum. Jumper ant venom caused haemolysis of guinea-pig blood. The degree of haemolysis was significantly reduced when boiled venom was used. These results suggest that jumper ant venom contains histamine and may cause the release of cyclo-oxygenase products. It also contains a heat-sensitive haemolytic factor.

Effects of prazosin on metabolism and body temperature in normothermic rabbits.

An attempt was made to study the influence of prazosin on thermoregulatory parameters. Two sets of experiments were carried out in rabbits. In the first set of experiments prazosin was given as 3 h infusion intravenously, (iv) (0.1, 0.25 and 0.5 mg/kg/h) or intracerebroventricularly, (icv) (20, 50 and 100 micrograms/animal) at an ambient temperature of 22 degrees C. Iv infusion caused a fall while icv administration a rise in body temperature. In the second set of experiments at different ambient temperatures (Ta = 4, 22, 28 degrees C) the following thermoregulatory parameters were recorded: rectal (Tre) and ear skin (Te) temperatures, metabolic rate (M), respiratory heat loss (Eres). The most evident result of iv infusion of prazosin in a dose of 0.25 mg/kg/h was a fall in Tre accompanied by a decrease in metabolic rate at ambient temperature of 4 degrees C. At Ta of 22 degrees C and 28 degrees C prazosin iv (0.25 mg/kg/h) induced only minimal changes in measured parameters. The results of the experiments may suggest that prazosin given peripherally induced hypothermia at Ta of 4 degrees C by inhibition of non-shivering thermogenesis.

Differences between the effect of prazosin and lysine-acetylsalicylate on some thermoregulatory parameters in nonfeverish rabbits.

Thermoregulatory responses to prazosin and lysine-acetylsalicylate (LAS) were investigated in afebrile rabbits at different ambient temperatures, i.e. at 5, 21 and 28 degrees C. In cold as well as in heat prazosin significantly inhibited the metabolic rate. This effect was accompanied by falls in rectal temperatures, particularly at the ambient temperature of 5 degrees C. Increases in ear skin temperatures became visible only when this drug was used in rabbits maintained in the thermoneutral environment. On the other hand LAS in all tested conditions indicated a marked metabolic activity associated with an intensified respiratory heat loss. As a consequence, the rabbits responded with slight increases in body temperature. The possible mode of thermoregulatory activity of prazosin is being considered in confrontation with that of LAS.

The influence of prazosin on E. coli lipopolysaccharide-induced fever and noradrenaline hyperthermia.

We investigated the effect of prazosin on experimental fever induced by E. coli lipopolysaccharide (LPS) and on noradrenaline hyperthermia in the rabbit. LPS and prazosin were administered iv and ivc, noradrenaline was administered only iv. Prazosin inhibited both LPS fever and noradrenaline hyperthermia in a dose-dependent manner. The results indicate the participation of alpha-adrenoceptor in the pyrogen fever and noradrenaline hyperthermia.

Effects of 5,7-dihydroxytryptamine and 6-hydroxydopamine on fever response in conscious rats.

The effects of 5,7-dihydroxytryptamine (5,7-DHT) and 6-hydroxydopamine (6-OHDA) on the febrile response to E. coli lipopolysaccharide (LPS) of unanesthetized rats examined. Depleting serotonin (5-HT) in brain with 5,7-DHT produced an attenuation in fever response to LPS, while depleting noradrenaline (NA) content in the preoptic area with 6-OHDA produced an opposite effect. However, 6-OHDA when given intraventricularly (icv) was without any significant effect on fever response to LPS. Presented data indicate that alterations in both noradrenergic and serotoninergic system of the rat brain affect the febrile response response to bacterial pyrogen. Moreover, one might conclude that integrity of noradrenergic neurons in central nervous system (CNS) in the rat is not essential for appearance of pyrogen fever.