Is it possible to build financially sucessful new towns? The Milton Keyness experience

The last generation of British new towns is being completed with the dissolution of the New Towns Development Corporations. As the final chapter of the new town movement in Britain draws to a close, this paper examines their financial success by focusing on Milton Keynes. Reputedly one of the most successful new towns, Milton Keynes was the last new town to be started and had the largest projected population. The paper examines the financial accounting reports from 1971 to 1993 and computes the economic returns for the new town as a whole and for each of the major property types. We find that Milton Keynes lost more than one-half a billion pounds. The paper explores why this happened and what the lessons are for new town development efforts around the world. The paper concludes that while it is possible to develop financially successful new towns, it is extremely difficult.

The utility of exercise testing after cardiac transplantation in older patients

BACKGROUND

The criteria for cardiac transplantation recipient selection, including the appropriate recipient upper age limit, continue to expand with an increasing number of recipients greater than 60 years of age. While others have reported their transplant experience in older recipients in terms of quality of life assessment, we have examined the role of exercise cardiopulmonary testing post-transplantation in older cardiac transplant recipients.

METHODS

We reviewed inpatient and outpatient charts of 28 patients 60 years of age or older who underwent orthotopic heart transplantation at Vanderbilt University Medical Center.

RESULTS

In this population, perioperative mortality of 7.1% and Kaplan-Meier survival at 1 and 5 years of 89 and 77%, respectively, were similar to the institutional 1-year (89%) and 5-year (75%) survival among younger adult transplant recipients. Exercise cardiopulmonary testing results were available in 22/25 patients surviving greater than 1 year. Both peak oxygen consumption and percentage of maximum VO2 were significantly greater among patients reporting NYHA Class 1 or 2 functional status, in comparison with those NYHA Class 3 or greater.

CONCLUSION

Following cardiac transplantation, survival of patients greater than 60 years of age is equivalent to that of younger patients at our institution. Exercise testing provides an objective measure of performance and correlates with subjective status following heart transplantation. Most patients demonstrate good functional status, with minimal symptoms and good exercise capacity. These results, although retrospective, suggest that cardiac transplantation remains a reasonable therapeutic option for patients greater than 60 years of age with end-stage cardiomyopathy.

Synthesis and transporter binding properties of (R)-2 beta, 3 beta- and (R)-2 alpha, 3 alpha-diaryltropanes

(R)-2-Aryl-2-tropinone (9) was synthesized from (R)-2-carbomethoxy-3-tropinone (5) and was used as the key intermediate for the synthesis of (R)-2 beta, 3 beta- and (R)-2 alpha, 3 alpha-diaryltropanes. Inhibition of radioligand binding studies at the dopamine, serotonin, and norepinephrine transporters showed that the (R)-3 beta-(4-methylphenyl)-2 beta-phenyltropane (3b, RTI-422) possessed an IC50 value of 1.96 nM at the dopamine transporter and was highly selective for this transporter relative to the serotonin and norepinephrine transporters.

Differential display of mRNA

Differential display of mRNA (DD) is a technique in which mRNA species expressed by a cell population are reverse transcribed and then amplified by many separate polymerase chain reactions (PCR). PCR primers and conditions are chosen so that any given reaction yields a limited number of amplified cDNA fragments, permitting their visualization as discrete bands following gel electrophoresis. This robust and relatively simple procedure allows identification of genes that are differentially expressed in different cell populations. Here we review DD including some recent modifications, and compare it with other techniques for analyzing differential mRNA expression.

Protein kinase C isoforms during the development of deciduomata in pseudopregnant rats

In this study, we determined the expression of protein kinase C (PKC) isoforms during trauma-induced decidualization. The findings revealed that at least five PKC isoforms (alpha, delta, zeta, iota and lambda) were present in both control and decidualized tissues. After trauma-stimulation, PKC alpha was down-modulated in the deciduomata but not in the myometrium. Down-modulation was compatible with the increase in cell mitosis which reached a maximum at 2-3 days. On the other hand, PKC zeta was not down-modulated. It was increased both in the deciduomata and myometrium, and paralleled the frequency of decidual cell mitosis. The PKC isoforms of delta, iota and lambda were also increased, but they were associated with the depression of cell mitosis. Therefore, these findings suggested that the variable expression of PKC isoforms in trauma-induced decidualizing tissue in pseudopregnant rats may be involved in the modulation of decidual cell growth.

gas7: A gene expressed preferentially in growth-arrested fibroblasts and terminally differentiated Purkinje neurons affects neurite formation

Growth arrest-specific (gas) genes are expressed preferentially in cells that enter a quiescent state. gas7, which we identified in serum-starved murine fibroblasts, is reported here to be expressed in vivo selectively in neuronal cells of the mature cerebral cortex, hippocampus, and cerebellum. gas7 transcripts encode a 48-kDa protein containing a structural domain that resembles sequences of OCT2, a POU transcription factor implicated in neuronal development, and synapsins, which have a role in modulating neurotransmitter release. Using in situ hybridization and immunocytochemical analysis, we show that GAS7 expression occurs prominently in cerebellar Purkinje cells and that inhibition of production in terminally differentiating cultures of embryonic murine cerebellum impedes neurite outgrowth from maturing Purkinje cells. Conversely, GAS7 overexpression in undifferentiated neuroblastoma cell cultures dramatically promotes neurite-like outgrowth. Collectively, our results provide evidence for an association between expression of this gas gene and neuronal development.

Video-assisted cardioscopy for left ventricular thrombectomy in a child

Left ventricular thrombus is a complication of myocardial infarction, ventricular aneurysm, cardiomyopathy, and myocarditis. Left ventriculotomy has been the standard approach for removal of left ventricular thrombus. This approach has produced an unacceptable incidence of ventricular dysfunction, arrhythmias, and aneurysm formation. We describe a case of left ventricular thrombus with systemic embolization in a patient with myocarditis. Video-assisted cardioscopy allowed visualization and removal of the thrombus via an aortotomy, thereby avoiding a left ventriculotomy.

Transcatheter closure of an extracardiac Fontan fenestration

As the extracardiac Fontan operation evolves, a reliable method for creating and subsequently closing communications between the systemic and pulmonary venous chambers would be useful. We describe a surgical technique for creating this "fenestration" and a complementary transcatheter technique that allows safe and reliable closure of these communications regardless of size and position.

Identification of a second stanniocalcin cDNA in mouse and human: stanniocalcin 2

It has recently been shown that mammals contain a gene encoding a protein that is related to stanniocalcin (STC), a hormone previously considered to be present only in bony fish where it plays a major role in Ca2+ homeostasis. Here we report the identification in the mouse and human of a cDNA, STC-2, that shows significant similarity to the first mammalian STC (which we now rename STC-1). Northern analysis revealed that mammalian STC-2, like STC-1, is expressed in a wide variety of tissues. In contrast to STC-1, the predicted amino acid sequence of STC-2 contains a cluster of histidine residues in the C-terminal portion of the protein, which suggests that STC-2 may interact with metal ions.

Production and characterization of monoclonal antibodies against Tal1 oncoprotein

TAL1 (or SCL) oncogene functions as a transcription regulatory factor that is necessary for the early development of all hematopoietic lineages. Aberrant expression of Tall protein in T cells is the cause of T-cell acute lymphoblastic leukemia (T-ALL) in children. We generated two hybridomas that secreted monoclonal antibodies (MAbs) that reacted strongly with GST-TAL(1-210) but not with GST fusion protein in ELISA assay. These two MAbs, TWN3 and TWN60, recognized TALI oncoprotein expressed in transfected COS-1 cells by Western blotting. In addition, both MAbs were also effective in detecting TAL1 oncoprotein in leukemic cells by immunoprecipitation and immunocytochemistry. Therefore, they should be useful in the studies of Tall protein functions in both hematopoietic development and oncogenesis.

Biodegradable polymer microspheres as vaccine adjuvants and delivery systems

Though vaccination has been the most cost-effective way of controlling infectious diseases, the logistics of delivering at least two to three doses of conventional vaccines for primary immunization to achieve protection are difficult and compliance is frequently inadequate, particularly in developing countries. In recent years biodegradable polymer microspheres have received much attention for the purposes of controlled release of antigens, (i) to reduce the number of doses needed for primary immunization to as few as a single dose and (ii) to target an antigen to microfold cells on mucosal surfaces after oral administration or to antigen-presenting cells after parenteral inoculations. A variety of vaccine antigens have been encapsulated in microspheres usually composed of poly (lactic/glycolic) acid (PLGA). Based on the size of the microspheres, molecular weight of polymer and ratio of lactic to glycolic acid in the polymer, the antigen may be targeted to various cells of the immune system or it may form a depot at the site of injection, allowing the slow release of the antigen for extended periods. Additionally, another adjuvant may be incorporated inside microspheres together with the antigen, further enhancing or modulating the immune response to the desired type. The major problems in developing controlled-release vaccines include instability of vaccine antigens during micro-encapsulation, storage and subsequent hydration. We encapsulated tetanus toxoid (TT) and Haemophilus influenzae type b capsular polysaccharide conjugated to TT (Hib-T) inside PLGA microspheres and evaluated the antibody levels in mice. A single injection of these micro-encapsulated vaccines elicited high antibody levels which persisted for several months. The antibody levels were similar or superior to those elicited by conventional formulations of AIPO4-adsorbed TT or soluble Hib-T conjugate vaccine.

Active site inhibited factor VIIa (DEGR VIIa) attenuates the coagulant and interleukin-6 and -8, but not tumor necrosis factor, responses of the baboon to LD100 Escherichia coli

Antitissue factor antibody attenuated the coagulopathic and lethal responses to LD100 Escherichia coli, whereas active site inhibited factor Xa inhibited only the coagulopathic response. In this study, we wished to determine: (1) whether active site inhibited factor VIIa blocks the coagulopathic and/or attenuates the lethal effects of LD100 E coli and (2) whether these effects are accompanied by attenuation of the inflammatory cytokine response to LD100 E coli. Eight baboons infused for 2 hours with LD100 E coli also were given five bolus infusions of DEGR VIIa of 280 microg/kg at T = -10 minutes, +2, 4, 6, and 8 hours and observed for changes in vital signs, and the concentrations of hemostatic components (fibrinogen, platelets, fibrin degradation products) and inflammatory mediators (tumor necrosis factor [TNF], interleukin-6 [IL-6], IL-8) at T = 0, 1, 2, 4, 6, and 8 hours. Eight control baboons were also infused with LD100 E coli alone and followed as described above. Four of the eight baboons treated with DEGR VIIa were permanent 7-day survivors versus none in the control group. The mean survival times for the treated and control groups were 116 +/- 22 and 26 +/- 8 hours, respectively. These values differed significantly from each other, (P = .0008). The decrease in platelet and fibrinogen concentrations and the increase in fibrin degradation products observed in the control group were significantly attenuated in the treated group, as was thrombosis of renal glomerular capillaries. Treatment with DEGR VIIa showed no effect on the peak TNF response to LD100 E coli at T = 2 hours (170 +/- 32 v 120 +/- 35 ng/mL). DEGR VIIa, however, did attenuate the IL-6 and IL-8 responses at T = 8 hours (ie, the IL-6 concentrations were 81 +/- 10 for treated and 1,256 +/- 236 for the control groups and the IL-8 concentrations were 28 +/- 3.9 for the treated and 60 +/- 8.2 for the control group). These values for IL-6 and IL-8 differed significantly from each other between the treated and control groups (P = .0001 and .0074, respectively). It should be noted that the initial responses of IL-6 and IL-8 up to T = 4 hours were not attenuated. We concluded that DEGR VIIa treatment attenuates inflammatory, as well as hemostatic system responses to LD100 E coli. We hypothesize that this occurs through interference with the assembly and/or interactions of tissue factor/VIIa complexes.

Lupus humoral autoimmunity induced in a primate model by short peptide immunization

BACKGROUND

Systemic lupus erythematosus (SLE) is characterized by humoral autoimmunity against the spliceosomal proteins, including Sm B/B'. In SLE patients with anti-Sm B/B' antibodies the proline rich sequence, PPPGMRPP, is the predominant Sm B/B' autoimmune epitope and appears to be an early target in the development of the anti-Sm B/B' response.

METHODS

Two female baboons were immunized with the PPPGMRPP peptide from the Sm B/B' spliceosomal protein constructed on a MAP backbone in Freund's adjuvant. One female control baboon was immunized with Freund's adjuvant alone. Baboon sera were collected and assessed for antibody binding to the spliceosomal proteins and compared to SLE patient and control sera.

RESULTS

Peptide immunized baboons developed antibodies to multiple regions of the Sm B/B' protein, as well as reactivity against other spliceosomal proteins. Consistent with serologic manifestations found in SLE, experimental baboons also acquired anti-nuclear antibodies, anti-nuclear ribonucleoprotein (nRNP) antibodies and, in one animal, anti-double stranded DNA antibodies. The control animal had none of these immunologic findings.

CONCLUSIONS

Immunization with PPPGMRPP is capable of initiating a humoral autoimmune response in primates against the Sm, nRNP complex from which the peptide was derived. The additional autoantibody specificities generated in experimental animals are similar to those found in human SLE sera. This study is the first evidence of peptide induction of SLE humoral autoimmunity in a primate model.

Human stanniocalcin (STC): genomic structure, chromosomal localization, and the presence of CAG trinucleotide repeats

Stanniocalcin (STC) is a glycoprotein hormone that is secreted by the corpuscle of Stannius, an endocrine gland of bony fish. It prevents hypercalcemia via mechanisms including inhibition of calcium uptake across the gills. Mammalian homologues have recently been reported but their function is unknown. Here we report the genomic organization and the transcription start site of the human STC gene and the existence of a polymorphic CAG trinucleotide repeat complex within the 5' untranslated region (UTR) of the mRNA and a smaller [CAG]6 repeat in the 3' UTR. As CAG repeats are associated with various human diseases, we used dual-color fluorescence in situ hybridization to localize the STC gene near markers D8S131 and D8S339 on chromosome 8p11.2-p21. STC should be considered a candidate gene for hereditary diseases mapped to this region.

Complement inhibition by FUT-175 and K76-COOH in a pig-to-human lung xenotransplant model

Two complement inhibitors, FUT-175 (FUT) and K76-COOH (K76), were studied as single agents in an ex vivo, in situ model of pig lung rejection by human blood. Pulmonary toxicity (primarily increased pulmonary vascular resistance [PVR]) was seen with FUT at a dose which inhibited complement in vitro (0.4 mg/ml); a lower dose (0.1 mg/ml) was therefore used. K76 had little apparent toxicity at a dose which inhibited complement in vitro (6 mg/ml), but activated complement, leading to C3a elaboration. Efficacy was then assessed by 1) deposition of complement pathway components in the lung and 2) lung survival during perfusion with human blood. Neither agent consistently prolonged median lung survival (FUT: 50 min. +/- 28 SEM; K76: 37 +/- 16), blocked thromboxane production, or prevented PVR elevation compared to experiments using unmodified human blood (survival 9 min. +/- 2). At the doses used, both agents prevented deposition of terminal complement complex (TCC) in the lung. This finding demonstrates that the various phenomena associated with hyperacute lung rejection (thromboxane release, PVR elevation, capillary leak, and intraalveolar hemorrhage) can all occur despite abrogation of membrane attack complex formation. We can not exclude a contribution by drug toxicity or complement damage (mediated by C3a or other complement pathway components proximal to TCC) to the observed lung injury. We conclude that, although both FUT and K76 inhibit deposition of TCC in the lung, at the dose tested neither drug is useful as a single agent to prolong survival in a pig-to-human lung xenograft model.

Localization of protein kinase C alpha and zeta during the decidualization in pseudopregnant rats

Our previous data showed that at least five PKC isoforms (alpha, delta, zeta, lambda and tau) were present in the decidualization. In this study, we then localized the PKC alpha and zeta by immunohistochemistry in the decidualized uterine tissues. The decidualized uterine tissues were induced by trauma-stimulation and fixed in formalin. The immunofluorescence were photographed by confocal microscope. The data revealed that the fluorescence of PKC alpha was present in the deciduomata and myometrium. In the deciduomata, PKC alpha was mainly located in the surrounding nuclear. This phenomenon of localization was especially performed on day 2 and 3 of the decidualization, just on the time of higher frequence of cell mitosis. Since the myometrium with hypertrophy did not display the phenomenon of perinuclear localization, these suggested that the expression and localization of PKC alpha may be associated with the cell proliferation. On the other hand, the PKC zeta was also present and distributed broadly in the deciduomata and myometrium. This expression was increased and similar to the previous Western blot studies. Thus, the data confirmed that the various expression and localization of PKC isoforms may be correlated with the development of deciduomata.

Continuous versus intermittent furosemide infusion in critically ill infants after open heart operations

BACKGROUND

Use of intravenous furosemide is generally avoided in critically ill neonates and infants soon after open heart operations to prevent fluctuations in intravascular volume and resulting circulatory instability.

METHODS

To assess and compare the safety and efficacy of continuous versus intermittent intravenous furosemide, we undertook a prospective, randomized trial in 26 consecutive patients less than 6 months of age. Inclusion criteria were presence of low-output syndrome requiring inotropic support (24/26 patients) or pulmonary hypertension requiring vasodilator therapy (10/26 patients) within 6 hours of discontinuation of cardiopulmonary bypass. Eleven patients received 0.1 mg x kg(-1) x h(-1) continuous intravenous furosemide (group 1) and 15 received 1 mg/kg bolus every 4 hours (group 2) for 24 hours. Mean age (3.7 +/- 3.4 versus 1.8 +/- 2.5 months) and weight (4.6 +/- 2.1 versus 4.3 +/- 1.7 kg) were comparable.

RESULTS

Group 2 infants showed slightly greater absolute urinary output (2.5 +/- 1.1 mL/kg per hour versus 3.3 +/- 1.1 mL/kg per hour, p = 0.05). However, urinary output per dose of drug was significantly larger in group 1 infants (1.0 +/- 0.4 versus 0.5 +/- 0.2 mL x kg(-1) x h(-1); p = 0.002) with lesser fluctuations (variance, 1.9 +/- 1.6 versus 3.8 +/- 2.1; p = 0.02) and fluid replacement needs (20.6 +/- 3.8 versus 51.8 +/- 14.4; p = 0.001). Electrolyte replacement requirements were similar. A trend toward greater hemodynamic instability in group 2 patients (heart rate variance 88.4 +/- 79.8 versus 128.3 +/- 82.7; p = 0.09; central venous pressure variance 2.8 +/- 1.90 versus 4.1 +/- 3.7; p = 0.07; mixed venous oxygen saturation variance, 32.3 +/- 27.6 versus 45.7 +/- 20.4; p = 0.06) was noted. All patients who completed the study protocol survived operation and were discharged home.

CONCLUSIONS

We conclude that (1) commonly used doses of both intermittent and continuous intravenous furosemide infusion can be safely administered to critically ill neonates and infants as early as 6 hours after operation, (2) continuous infusion yields an almost comparable urinary output with a much lower dose of furosemide, and (3) intermittent administration is associated with greater fluctuations in urinary output and greater needs for fluid replacement therapy.

Emergent stent placement for acute Blalock-Taussig shunt obstruction after stage 1 Norwood surgery

A neonate underwent a stage 1 Norwood surgery for hypoplastic left heart syndrome and subsequently developed profound cyanosis and hemodynamic instability. Catheterization revealed an occluded modified Blalock-Taussig shunt. Angioplasty and stent implantation resulted in immediate angiographic and clinical improvement, which has persisted at 5-month follow-up. This therapy may provide lifesaving treatment in selected patients.

7E3 F(ab')2, a monoclonal antibody to the platelet GPIIb/IIIa receptor, protects against microangiopathic hemolytic anemia and microvascular thrombotic renal failure in baboons treated with C4b binding protein and a sublethal infusion of Escherichia coli

We have used our previously described baboon model of infusion of both a sublethal dose of Escherichia coli and C4b binding protein to assess the impact of inhibiting platelet function with the F(ab')2 fragment of the monoclonal antibody 7E3, directed against the platelet glycoprotein (GP)IIb/IIIa receptor, on the characteristic microvascular changes. At a dose of 0.25 to 0.35 mg/kg bolus plus an infusion of 0.25 to 0.35 mg/kg over 6 hours, c7E3 F(ab')2 had only a minimal impact on fibrinogen consumption and delayed but did not prevent, the development of thrombocytopenia. Treatment with 7E3 F(ab')2, however, produced significant protection from the development of microangiopathic hemolysis and renal insufficiency. Histologic examination supported these observations, with treated animals having fewer schistocytes on blood smear and less evidence of ischemic renal changes. Treated animals also had more rapid recovery of peripheral white blood counts, suggesting a possible protective effect of treatment on ischemic damage to the bone marrow. These data indicate that potent inhibition of platelet function via GPIIb/IIIa receptor blockade can decrease ischemic organ damage in this animal model that has features similar to those found in diffuse intravascular coagulation, hemolytic uremic syndrome, and thrombotic thrombocytopenic purpura.

Synthesis and transporter binding properties of 2,3-diphenyltropane stereoisomers. Comparison to 3beta-phenyltropane-2beta-carboxylic acid esters

2beta,3beta-Diphenyl-(5), 2alpha,3alpha-diphenyl-(6), and 2alpha,3beta-diphenyltropane (3) as well as 2,3-diphenyltrop-2-ene (4) were prepared in racemic form and assayed for inhibition of radioligand binding at the dopamine (DA), serotonin (5-HT), and norepinephrine (NE) transporters. Among all three transporters, compounds 4-6 bound the DA transporter with the highest affinity. The 2beta,3beta-diphenyltropane (5) bound the DA transporter with an IC50 value (28 nM) almost identical to that of 3beta-phenyltropane-2beta-carboxylic acid methyl ester (WIN 35,065-2) and has much greater selectivity relative to binding to the serotonin transporter. A comparison of the radioligand data from this study to radioligand data obtained on other WIN 35,065-2 analogs suggests that hydrophobicity of the C-2 substituent of some analogs of the WIN 35,065-2 class may be an important contributing factor to binding at the DA transporter.

Determination of protein loading in biodegradable polymer microspheres containing tetanus toxoid

Various methods to determine loading of vaccine in biodegradable polymer microspheres encapsulating tetanus toxoid were evaluated. The microspheres were composed of poly (D-lactic acid) (PLA) and poly (DL-lactic-co-glycolic acid) (PLGA). Dissolution of microspheres in organic solvents such as methylene chloride, chloroform, or dimethyl sulfoxide and extraction of vaccine antigen or total protein with phosphate buffered saline gave variable results which depended upon the characteristics of the microspheres, such as type of polymer, excipients used in the microspheres and formulation conditions. Microspheres made from low molecular weight PLGA polymer and showing a large burst release exhibited up to 25% extraction of antigen whereas microspheres made from PLA microspheres with low burst release showed < 1% extraction. Extraction of total protein with 0.1 N NaOH and 5% sodium dodecyl sulfate showed results similar to those obtained with organic solvent extraction method. Partial digestion of microspheres with 6 N HCl at 60 degrees C for 20 h resulted in approximately 30% loss in TT protein by micro-bicinchoninic acid (BCA) assay. The major problem with this method was strong reactions in the micro-BCA assay of stabilizers, particularly sugars (glucose, sucrose) used in the microsphere formulations. Complete digestion of microspheres with 6 N HCl at 110 degrees C for 20 h or with 13.5 N NaOH at 121 degrees C for 1 h and quantitation of amino acids by a modified ninhydrin assay showed reproducible results on the protein loading in the microspheres. However, this method was affected by the presence of stabilizers, such as gelatin, which contain amino acids. Further, sucrose concentrations higher than 10% caused interference in the ninhydrin assay on samples hydrolyzed with 6 N HCl. In contrast, hydrolysis with 13.5 N NaOH did not show any interference by sucrose. Stabilizers used outside the microspheres for lyophilization purposes may be removed by washing the microspheres before loading determination or by dialysis but stabilizers used inside the microspheres would still cause interference. For reliable determination of total protein in the microspheres containing vaccines, we suggest complete digestion of microspheres with acid or base followed by amino acid analysis by colorimeteric assays such as ninhydrin method or using amino acid analyzers. The method needs to be optimized for each type of formulation to eliminate interference by the excipients. Alternatively, total protein nitrogen in the microspheres may be determined by the Kjel-dahl method if no amino acids or other nitrogen containing stabilizer is used inside the microspheres.

Extracardiac Fontan operation without cardiopulmonary bypass

Choreoathetosis developed after bilateral bidirectional cavopulmonary anastomosis in a 17-month-old boy with univentricular heart. To avoid exacerbating this neurologic problem, the Fontan operation was later completed without cardiopulmonary bypass. The left cavopulmonary anastomosis maintained pulmonary blood flow. A tube graft was anastomosed to the junction of the right cavopulmonary anastomosis. A femoral vein-to-right atrial shunt was established, the inferior vena cava divided, the cardiac end oversewn, and the noncardiac end anastomosed to the tube graft.

A guinea pig ileum preparation devoid of functional kappa receptors: a new in vitro pharmacologic assay for mu-opioid ligands

Guinea pig ileum longitudinal muscle/myenteric plexus preparations contain functional mu- and kappa-opioid receptors. A preparation with blocked kappa receptors was obtained by pretreating guinea pigs with 0.1-10.0 mg/kg intraperitoneal doses of a new kappa-selective affinity label, DIPPA (2-(3,4-dichlorophenyl)-N-methyl-N-[1S-1-(-3-isothiocyanatophenyl)-2-(-1 -pyrrolidinyl) ethyl] acetamide). Determination of IC50 values for the mu-selective agonist DAMGO ([D-Ala2,MePhe4,Gly(ol)5]-enkephalin) and the kappa-selective agonist U 69,593 ([5alpha,7alpha,8beta]-(+)-N-methyl-N-[7-(1-pyrrolidin yl)-1-oxaspiro-(4,5)-dec-8-yl]) showed that 0.5 mg/kg DIPPA at 48 h produced reliable, near-complete blockade of kappa-opioid activity but a minimal shift for kappa-opioid agonism. This new assay should be useful for studying mixed agonists/antagonists that produce strong kappa-opioid receptor agonism, which prevents determination of mu-opioid receptor antagonism.

Characteristics of tumor cell bioactivity in oncogenic osteomalacia

Oncogenic osteomalacia is a condition where renal phosphate wasting occurs causing defective mineralisation, in the presence of a tumor. Cultures of cells were established from a hemangiopericytoma resected from a patient with oncogenic osteomalacia. Conditioned media from the cells inhibited phosphate uptake in opossum kidney cells and stimulated of cAMP in rat osteosarcoma cells, a standard parathyroid hormone (PTH)-like assay. This cAMP stimulation was suppressed by the PTH analogue, 3-34 bPTH and also by heat and trypsin treatment of the media. Tests of conditioned media for PTH and parathyroid hormone related protein (PTHrP) immunoreactivity were negative, however, and no hybridisation to probes for PTH, PTHrP or human stanniocalcin was detected in tumor cell RNA on Northern blot. These data support the hypothesis that tumors responsible for oncogenic osteomalacia produce a humoral substance that reduces renal phosphate reabsorption and provide evidence that the factor may act via PTH/PTHrP receptors.