Superior autologous blood stem cell mobilization from dose-intensive cyclophosphamide, etoposide, cisplatin plus G-CSF than from less intensive chemotherapy regimens

The study purpose was to determine if G-CSF plus dose-intensive cyclophosphamide 5.25 g/m2, etoposide 1.05 g/m2 and cisplatin 105 mg/m2 (DICEP) results in superior autologous blood stem cell mobilization (BSCM) than less intensive chemotherapy. From January 1993 until May 1997, 152 consecutive patients with non-Hodgkin's lymphoma (n = 55), breast cancer (n = 47), Hodgkin's disease (n = 14), multiple myeloma (n = 9), AML (n = 9), or other cancers (n = 18) initially underwent BSCM by one of three methods: Group 1: G-CSF alone x 4 days (n = 30). Group 2: disease-oriented chemotherapy, dosed to avoid blood transfusions, followed by G-CSF starting day 7 or 8, and apheresis day 13 or 14 (n = 82). Group 3: DICEP days 1-3, G-CSF starting day 14, and apheresis planned day 19, 20 or 21 (n = 40). A multivariate analysis was performed to determine which factors independently predicted BSCM. The median peripheral blood CD34+ (PB CD34+) cell count the morning of apheresis linearly correlated with the number of CD34+ cells removed per litre of apheresis that day. The median PB CD34+ cell count and median CD34+ cells x 10(6) removed per litre of apheresis were highest for Group 3, intermediate for Group 2, and lowest for Group 1. By multivariate analysis, mobilization group (3 > 2 > 1), disease other than AML, no prior melphalan or mitomycin-C, and less than two prior chemotherapy regimens predicted better BSCM. Out of 15 Group 3 patients who had infiltrated marrows, 11 had no detectable cancer in marrow and apheresis products after DICEP. These data suggest that DICEP results in superior BSCM than less intensive chemotherapy regimens.

Quinine-induced immune thrombocytopenic purpura followed by hemolytic uremic syndrome

Immune thrombocytopenic purpura (ITP) mediated by quinine-dependent platelet reactive antibodies is well recognized. More recently there have been a number of reports of quinine-induced hemolytic-uremic syndrome (HUS). We describe a patient with quinine-induced immune thrombocytopenia who subsequently developed HUS after re-exposure to a single dose of this drug. To our knowledge, this is the first such case reported. Multiple quinine-dependent antibodies have been characterized in the patient's serum. Initially, quinine-dependent antibodies were directed solely against the platelet glycoprotein complex GPIb/IX. After rechallenge with quinine, there was broadening of quinine-dependent antibody specificities, which were now also directed against the platelet glycoprotein complexes GPIb/IX and GPIIb/IIIa, endothelial cells, and leukocytes. We have shown quinine-dependent antibody-mediated endothelial cell activation, which supports an immunopathogenic role for quinine-dependent antibodies in the causation of this disease.

Nuclear factor I regulates expression of the gene for phosphoenolpyruvate carboxykinase (GTP)

Nuclear factor-I (NFI) binds to the phosphoenolpyruvate carboxykinase (GTP) (PEPCK) gene promoter immediately 5' to the cAMP regulatory element (CRE). This suggests an interaction between NFI and factors that bind the CRE. Of the four NFI isoforms expressed in mammalian tissues, NFI-A and -B stimulate basal transcription from the PEPCK gene promoter in HepG2 cells, while NFI-C and -X are slightly inhibitory. All four NFI isoforms abrogate the 20-fold protein kinase Ac (PKAc)-mediated induction of transcription from the PEPCK gene promoter. Normal PKAc-mediated induction was noted when the CRE was moved 10 base pairs 3' of its original location. However if the CRE was moved 5 base pairs 3', placing it out of phase with the other elements in the promoter, or moved 5' to -285 (the P3(I) site in the promoter), some PKA-mediated stimulation was lost. The NFI-C isoform effectively inhibited PKAc induction regardless of the relative positions of the CRE and the NFI binding sites. NFI-C also abrogated cAMP regulatory element-binding protein (CREB)-induced activity of wild type and mutant PEPCK promoters. There was some cooperativity in the binding of CREB and NFI to their respective binding sites but this did not appear to be physiologically important.

Single-agent high-dose melphalan salvage therapy for Hodgkin's disease: cost, safety, and long-term efficacy

BACKGROUND

Few data are available on the cost, safety, and long-term efficacy of single-agent high-dose melphalan (HDM) followed by autologous bone marrow (ABMT) or blood stem cell (ABSCT) transplantation in the salvage therapy of Hodgkin's disease (HD).

PATIENTS AND METHODS

From February 1981 to September 1996, 23 patients with relapsed (n = 15) or refractory (n = 8) HD received salvage therapy with HDM 140-200 mg/m2 followed by non-cryopreserved ABMT (n = 18) or cryopreserved ABSCT (n = 5). The cost of HDM/ABSCT in 1996, from initial consultation until transfer back to referring physician, was determined and compared to the estimate costs of two multi-agent regimens commonly used for HD.

RESULTS

HDM was well tolerated with no early transplant-related mortality. The five-year overall and progression-free survival rates were 52% and 50%, respectively. The average total cost in Canadian funds of HDM/ABSCT in 1996 was $34,400/patient. This cost was estimated to be $4,700-6,800 cheaper per patient than the multi-agent high-dose regimens.

CONCLUSION

These data suggest that HDM is safe, feasible, active, and reasonably inexpensive salvage therapy for patients with relapsed/refractory HD.

Effect of hypothyroidism on adenylyl cyclase activity and subtype gene expression in brown adipose tissue

Brown adipose tissue (BAT) expresses several adenylyl cyclase (AC) subtypes, and adrenergic stimulation selectively upregulates AC-III gene expression. Previous studies have described synergistic interactions between the sympathetic nervous system (SNS) and 3,5,3'-triiodothyronine (T3) on the regulation of gene expression in BAT. Because adrenergic stimulation also increases the activity of BAT type II thyroxine 5'-deiodinase (DII) and local T3 generation is important for many functional responses in BAT, we examined the effects of thyroid hormone status on the expression of various AC subtypes. Hypothyroidism selectively increased AC-III mRNA levels in BAT but not in white adipose tissue. Of the other subtypes examined, hypothyroidism did not alter AC-VI mRNA levels and slightly reduced AC-IX mRNA levels in BAT. The increase in AC-III expression was paralleled by an increase in forskolin-stimulated AC activity in BAT membranes. Sympathetic denervation of BAT abolished the increase in both AC activity and AC-III mRNA expression produced by hypothyroidism, but did not affect the expression of other subtypes. Surgical denervation also prevented the induction of AC-III in the cold-stressed euthyroid rat, but injections of T3 failed to alter AC-III expression in intact or denervated BAT. Our results indicate that T3 does not directly affect expression of AC-III. Rather, hypothyroidism increases BAT AC-III expression indirectly via an increase in sympathetic stimulation. Furthermore, our results strongly indicate that the increase in AC activity in hypothyroid BAT is due to increased expression of AC-III.

Partially mismatched blood cell transplants for high-risk hematologic malignancy

Eleven patients with high-risk hematologic malignancy received cryopreserved but otherwise unmanipulated blood cell transplants (BCT) from partially mismatched family members in whom progenitor cells had been mobilized by G-CSF. Donors were mismatched by up to one antigen in the GVH direction and up to three antigens in the rejection direction. Outcomes were compared with those of 22 patients receiving BCT from fully matched donors. Two mismatched patients died without engraftment on day 21 and 32. One had rejected bone marrow from the same donor, the other was mismatched by two antigens in the rejection direction and received the lowest dose of CD34+ cells. Median time to granulocyte engraftment was 21.5 (range 16-33) days for the mismatched group compared with 16 (11-28) days for the matched group (P = 0.01). No correlation was found between CD34+ cell dose and time to granulocyte or platelet recovery. In the mismatched and matched BCT groups respectively, the risk of grade II-IV acute graft-versus-host disease (GVHD) was 73% vs 28% (P = 0.001) and of chronic GVHD 100% vs 78% at 18 months (P = 0.01). The relationship of T cell dose to acute GVHD could only be evaluated in the matched group and no correlation was found. One of 11 mismatched patients and eight of 22 matched patients had relapse or persistent disease. Disease-free survival at 1 year was similar at 55% for mismatched and 50% for matched BCT. These results indicate that allogeneic BCT from partially mismatched family members is accompanied by a high incidence of GVHD but may result in comparable survival to BCT from fully matched donors.

Second allogeneic transplants for leukemia using blood instead of bone marrow as a source of hemopoietic cells

There is increasing interest in blood cell transplants (BCT) from normal donors as an alternative to BMT. Ten patients with relapsed or persistent leukemia after BMT received intensive cytotoxic conditioning followed by allogeneic BCT. Three BCT were from single-antigen mismatched donors; two of the corresponding recipients had rejected a BMT from the same donor. Two patients received BCT from a different donor (one matched, one single-antigen mismatched). The other six BCT were from the same, fully matched, bone marrow donors. Donors were given G-CSF to mobilize progenitor cells which were collected by a single 2-4 h leukapheresis. Methotrexate, CsA and folinic acid were used for GVHD prophylaxis for all transplants but CsA was discontinued sooner after BCT than after BMT. One patient died without engraftment having rejected a BMT from the same single-antigen mismatched donor 4 years previously. Nine patients had granulocyte recovery at a median of 14 days, up to 6 days faster than with their previous BMT. Platelet recovery was also 2-6 days faster than with BMT in four previously engrafting patients. Four patients died without platelet recovery after BCT within a year of BMT, three of treatment-related toxicity and one of relapse. Two patients developed grade II acute GVHD. Of six patients given BCT more than a year from BMT, four, all with acute leukemia, survive 7, 14, 29 and 29 months after BCT and one relapsed at 7 months. All four survivors developed chronic GVHD. These results indicate that BCT may be useful therapy for relapse occurring more than a year after BMT.

Allogeneic blood cell transplants for haematological malignancy: preliminary comparison of outcomes with bone marrow transplantation

Twenty-six patients with haematological malignancy received cryopreserved but otherwise unmanipulated blood cell transplants (BCT) from five- or six-antigen matched siblings in whom progenitor cells had been mobilized by G-CSF. Outcomes were compared with a historical control group of 26 BMT patients matched for age and disease status. Granulocyte counts recovered to 0.5 x 10(9)/l in a median of 16 days after BCT compared with 21.5 days after BMT (P = 0.0002). Platelet counts, unsupported for 3 days, reached 20 x 10(9)/l in a median of 14 days vs 20.5 days (P = 0.0003) after BCT compared with BMT in those patients who engrafted. In the BCT and BMT groups, respectively, the risk of grade II-IV acute GVHD was 37 vs 21% (P = 0.16) and of chronic GVHD at 1 year 53 vs 48% (P = 0.9). There was no significant difference in red cell transfusions but BCT patients required fewer platelet transfusions (median 3 vs 5, P = 0.015) and fewer days in hospital (20.5 vs 25, P = 0.02). These results indicate that allogeneic BCT from matched and partially mismatched family donors result in faster engraftment than BMT without a significant increase in GVHD. Allogeneic BCT may prove to be a more tolerable procedure than BMT for both donor and recipient and there are indications of improved cost-effectiveness.

Perinatal expression of adenylyl cyclase subtypes in rat brown adipose tissue

The ability of norepinephrine to stimulate adenylyl cyclase (AC) activity increases during the perinatal period in rat brown adipose tissue (BAT), and this increase is associated with changes in the activities of both GS alpha and AC. The purpose of this study was to determine which AC subtypes are present in neonatal BAT and to examine whether the perinatal increase in AC activity corresponds to an increase in the expression of a particular AC subtype. Analysis of AC mRNAs by nuclease protection assay demonstrated the presence of mRNAs encoding AC-III, AC-IV, AC-VI, and AC-IX in embryonic and postnatal BAT. Of the subtypes detected, only AC-III mRNA levels increased substantially during the perinatal period. The increase in AC-III expression was paralleled by an increase in isoproterenol-stimulated AC activity. Treatment of neonates was the sympathetic neurotoxin 6-hydroxydopamine abolished the perinatal increase in both AC activity and AC-III mRNA levels but had no effect on the expression of other AC subtypes. These results strongly indicate that the increase in AC activity during the perinatal period is due to an increase in the expression of AC-III.

Advances in the use of somatostatins in the management of endocrine tumors

With the introduction of long-acting somatostatin analogues, several advances have been made in the management of endocrine tumors. Octreotide was first used for the management of acromegaly and later used for metastatic gastroenteropancreatic tumors. Somatostatin receptor imaging has recently been introduced not only for the localization of somatostatin receptor-positive tumors but also for selection of optimal therapy. In addition to inhibitory effects on exocrine and endocrine secretion, octreotide has also been suggested to have antiproliferative effects manifested mainly by stabilization of disease and not tumor regression.

Is the "atypical" beta-receptor in the rat stomach fundus the rat beta 3 receptor?

The rat gastric fundus is known to possess an "atypical" beta-adrenergic receptor that mediates relaxation to isoproterenol. The purpose of this study was to characterize the relationship between this "atypical" beta receptor in the rat stomach and the cloned rat beta 3 receptor by taking advantage of highly selective pharmacological and molecular biological probes of the beta 3 receptor. Nuclease protection analysis of RNA from the rat gastric fundus identified beta 3 receptor mRNA whose levels in the stomach were exceeded only by those in adipose tissue. Pharmacological analysis of the recombinant rat beta 3 receptor expressed in Chinese hamster ovary cells indicated low affinity of propranolol with a Ki value of 2.3 microM. Therefore, 0.3 microM propranolol was chosen as a concentration that would completely block beta 1 and beta 2 receptors (Ki = 1-5 nM) but would leave beta 3 receptors largely intact in the rat stomach fundus. In the presence of propranolol, several beta-adrenergic receptor agonists relaxed the rat stomach fundus with a rank potency order of (R,R)-5-[2-[[2-(3-chlorophenyl)-2-hydroxyethyl]-amino]-propyl]1,3- benzodioxole-2,2-dicarboxylate (CL316,243) > isoproterenol > norepinephrine = epinephrine = dl-4-3[(1,1-dimethylethyl)amino]-2- hydroxylproproy]1,3 dihydro-2H-benzimidazol-2-one hydrochloride (CGP12177) > clenbuterol > terbutaline > pindolol. Isoproterenol, norepinephrine and epinephrine were full agonists, whereas (R,R)-5-[2-[[2-(3-chlorophenyl)-2- hydroxyethyl]-amino]-propyl]1,3-benzodioxole-2,2-dicarboxylate was only a partial agonist with 66% intrinsic activity relative to isoproterenol.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of cell type upon the desensitization of the beta 3-adrenergic receptor

Previous studies have suggested that the beta 3 receptor fails to become desensitized following acute agonist exposure. We have determined whether this resistance to desensitization is an intrinsic property of the human beta 3 receptor by examining beta 3 receptor-stimulated adenylyl cyclase activity in several cell types. Prior exposure to ISO significantly decreased beta 3 receptor-stimulated adenylyl cyclase activity in SK-N-MC human neuroepithelioma cells, which natively express the beta 3 receptor. ISO pretreatment significantly desensitized the recombinant beta 3 receptor when stably expressed in 293 cells, but not when the receptor was expressed in Chinese hamster ovary cells. Mutant receptors lacking the second exon of the human beta 3 receptor also underwent agonist-induced desensitization when expressed in 293 cells. Additionally, the rat beta 3 receptor, which fails to desensitize in rat adipocytes, underwent agonist-induced desensitization when expressed in 293 cells. Pretreatment with CGP 12177A, a beta 3-selective agonist, also reduced beta 3-stimulated adenylyl cyclase activity in transfected 293 cells. In contrast, 8-Br-Cyc AMP did not desensitize the beta 3 receptor. Concanavalin A, an inhibitor of receptor sequestration failed to prevent ISO-induced desensitization of the beta 3 receptor. Furthermore, radioligand binding studies showed that ISO pretreatment did not cause a loss of beta 3 receptors from 293 cell membranes. The results of the present study indicate that beta 3 receptor desensitization is dependent upon the cellular background in which this receptor is expressed. Furthermore, the mechanism responsible for beta 3 receptor desensitization does not appear to involve sequestration, cyclic AMP-dependent phosphorylation or down-regulation of the receptor.

Expression of transforming growth factors beta 1, beta 2, beta 3 in neuroendocrine tumors of the digestive system

Neuroendocrine tumors of the digestive system are slowly growing neoplasms which often present pronounced fibrosis around tumor cells and in the peritoneal cavity. In this study, 23 midgut carcinoids and 7 endocrine pancreatic tumors were examined for the presence of TGF-beta with affinity-purified polyclonal antibodies raised against synthetic peptides coding for a specific region of latency-associated peptide sequences of TGF-beta 1, -beta 2, -beta 3, a rabbit anti serum against TGF-beta binding protein (LTBP) and a rabbit polyclonal antibody against TGF-beta type II-receptor (TGF-beta RII). Tumor cells from most tissues expressed all three isoforms of TGF-beta but LTBP was only weakly expressed. In stromal cells abundant expression of TGF-beta 2 and LTBP was found, whereas TGF-beta 1 and TGF-beta 3 were expressed only weakly. TGF beta RII immunoreactivity was observed mostly in the stromal cells. Tissue sections from 4 of these neuroendocrine tumors were also investigated by in situ hybridization. Strong signals on tumor cells were detected with TGF-beta 2 and TGF-beta 3 cRNA probes and also weakly with TGF-beta 1 and LTBP cRNA probe. Strong positive signals were observed on stromal cells with TGF-beta 2 and LTBP probe whereas only weak signals were observed on the stromal cells with TGF-beta 3 probe. Strong signals were detected on stromal cells with TGF-beta RII probe whereas no signals were observed on tumor cells. Our data suggest that TGF-beta might play an important role in the interaction of tumor and stromal cells. Thus TGF-beta might stimulate matrix production and angiogenesis of stromal cells, whereas tumor cells themselves are unaffected by the growth inhibitory activity of TGF-beta.

Differential interaction of beta 1- and beta 3-adrenergic receptors with Gi in rat adipocytes

The interaction of beta 1- and beta 3-adrenergic receptors and G(i) proteins was examined in rat adipocytes. In intact adipocytes, cyclic AMP accumulation stimulated by the beta 3-selective agonist, BRL 37344 (BRL), was potentiated by pertussis toxin (PTX), as was the beta 1-sensitive component of isoproterenol (ISO)-stimulated cyclic AMP accumulation. These data suggest that beta 1 and beta 3-receptors interact with both Gs and G(i) in intact adipocytes. Further analysis of the activation of adenylyl cyclase by the beta-receptor subtypes was performed in adipocyte membranes in which the activity of G(i) was manipulated by both GTP and PTX. Unlike cyclic AMP accumulation in cells, the activation of membrane adenylyl cyclase by ISO could be clearly resolved into components mediated by beta 1-(high affinity) or beta 3-(low affinity) receptors. The beta 3-receptor-mediated activity was dramatically reduced at 0.1 mM GTP compared to 0.1 microM GTP, but the activity mediated by beta 3-receptors was significantly reduced at concentrations of GTP in which G(i) proteins are active. Adenylyl cyclase activity stimulated by BRL was also inhibited at high concentrations of GTP. PTX abolished the inhibition of beta 3-receptor-stimulated activity by high GTP concentrations. This is the first study to indicate that G(i) proteins can limit beta 3- but not beta 1-stimulated adenylyl cyclase activity and are consistent with the hypothesis that beta 3-receptors interact with both Gs and G(i), whereas beta 1-receptors couple predominantly to Gs.

Different splice variants of CD44 are expressed in gastrinomas but not in other subtypes of endocrine pancreatic tumors

Endocrine pancreatic tumors are neuroendocrine neoplasms with malignant potential and give rise to varied clinical syndromes due to excessive secretion of multiple hormones. In this study 22 endocrine pancreatic tumors and 11 carcinoid tumors were examined for the expression of CD44 using a monoclonal antibody. CD44 gene activity of 11 endocrine pancreatic tumor tissues and five carcinoid tumor tissues was also studied by amplifying messenger RNA with the polymerase chain reaction followed by electrophoresis and blot hybridization. Strong immunoreactivity was detected on all gastrinomas examined (P < 0.001), and in two non-functioning endocrine pancreatic tumors. Such immunoreactivity was not observed in other subtypes of endocrine pancreatic tumors. In the normal human pancreas, the acinar portion and ductal epithelial cells stained strongly positive but pancreatic islet cells did not show any significant immunostaining. Furthermore, in endocrine pancreatic tumors with metastatic disease, CD44-positive tumors had a tendency to metastasize to lymph nodes (P = 0.005), as compared with CD44-negative tumors which were locally invasive or metastasized to the liver. Although, in this limited material and short follow-up, we were not able to show any statistical significance, patients with CD44-negative endocrine pancreatic tumors had prolonged survival time compared with patients with CD44-positive tumors (73% versus 59% at 5 years; P = 0.7). Of 10 carcinoid tumors examined, all three foregut carcinoids and one midgut carcinoid stained strongly positive, whereas all other midgut carcinoids were negative. Analysis of CD44 splice variants showed that in all five gastrinomas there was overproduction of alternatively spliced larger molecular variants as compared with other types of endocrine pancreatic tumors and carcinoid tumors. The band pattern from one case of carcinoid tumor with a fulminant clinical course was similar to that of gastrinomas, whereas other carcinoid tumors expressed the epithelial form of CD44. The earlier identified splice variants which confer metastatic behavior on a pancreatic tumor cell line were not expressed in neuroendocrine tumors. Our data indicate that CD44 expression in endocrine pancreatic tumors correlates with the ability to give rise to lymph node metastases and may play a vital role in determining the fate of metastasizing cells. Moreover, because gastrin is not detectable in the normal human pancreas, the pancreatic ductal cell positivity for CD44 strengthened the ductal origin concept of gastrinomas. The band pattern of CD44 splice variants suggests that the previously described splice variants conferring metastatic behavior do not accompany metastatic activity of neuroendocrine tumors.

Characterization of the human beta 3-adrenergic receptor gene

Comparison of the rodent and human beta 3-adrenergic receptor cDNAs with the respective genomic sequences has revealed unexpectedly that these genes contain two protein-coding exons. The rat gene was cloned recently and was found to contain three exons and two introns. In the present report, the human beta 3 receptor gene was characterized and was found to consist of two exons and a single intron. Sequence analysis of the human beta 3 receptor gene identified regions in the intron that were homologous to the second exon and second intron of the rat gene. It appears that both species utilize homologous 5' donor sites in the first intron and 3' acceptor sites of the final exon. However, splicing signals within the human intron that are homologous to the second exon of the rat gene are not used. Nuclease protection assays of tissue RNA and polymerase chain reaction-amplified cDNA demonstrated conclusively that beta 3 receptor mRNA, containing two protein-coding exons, is expressed in human adipose and intestinal tissues. The pharmacological properties of the full length human beta 3 receptor were determined for the first time in Chinese hamster ovary cells, where catecholamine agonists activated adenylyl cyclase with low potency. The beta 3 receptor agonists CGP 12177 and BRL 37344 also activated adenylyl cyclase. CGP 12177 was 10-15 times more potent than either isoproterenol or BRL 37344 in stimulating adenylyl cyclase activity. These pharmacological properties differed somewhat from those reported previously for Chinese hamster ovary cells expressing the truncated receptor. However, direct comparison indicates that it is unlikely that the amino acid sequence derived from the second exon can account for these differences.

Occurrence of pyuria and bacteriuria in asymptomatic hemodialysis patients

Patients with end-stage renal disease on hemodialysis have documented defects in their immune responses, and infections contribute significantly to their morbidity and mortality. This study prospectively detected and quantitated leukocyturia and bacteriuria in asymptomatic hemodialysis patients. Thirty-one percent of asymptomatic hemodialysis patients had significant pyuria (> 10 white blood cells per high-power field) and 25% had bacteriuria of pathologic dimensions, (> 1 x 10(5)/mL of a single microorganism). Pyuria was a good marker for significant bacteriuria in these patients. These results demonstrate that the urinary tract, even in ESRD patients on hemodialysis, may represent a significant reservoir for infection.

Expression of growth factor peptides and their receptors in neuroendocrine tumors of the digestive system

Neuroendocrine tumors of the digestive system are slow growing neoplasms which often present with pronounced fibrosis around tumor cells and in the peritoneal cavity. In this report 30 midgut carcinoids and endocrine pancreatic tumors were examined for the expression of peptide growth factors and their receptors, both by immunohistochemistry and in situ hybridization. Our data indicate that multiple peptide growth factors, PDGF, TGF-beta, and bFGF are expressed by these tumors. PDGF was expressed on tumor cells and stroma in 70% of tissues examined. PDGF alpha-receptor was seen on clusters of tumor cells and occasionally on adjacent stroma, whereas PDGF beta-receptor was seen only in the stroma. Our data suggest that PDGF may be involved in the autocrine stimulation of tumor cells and stimulation of stromal cell growth through paracrine and possibly autocrine mechanism. In addition, tumor tissues express all three isoforms of TGF-beta in more than half of the tissues examined. Tumor cells produce small latent complexes causing an escape from potent inhibitory effect of TGF-beta and stimulation of stromal cell growth and matrix deposition through paracrine mechanism. bFGF, a potent stimulant of endothelial cell growth, was expressed by all tumor tissues examined. Our data suggest that multiple peptide growth factors may have an important role in tumor progression and desmoplastic reaction accompanying these tumors.

Adrenergic regulation of neonatal brown fat adenylyl cyclase and Gs alpha activity

Norepinephrine (NE)-stimulated adenylyl cyclase (AC) activity increases during the perinatal period in rat brown adipose tissue (BAT), and this increase is associated with changes in the activities of both the catalytic subunit (C) and Gs alpha, the GTP-binding protein that mediates activation of C. The present study examined the role of the sympathetic nervous system in the postnatal sensitization of AC. The sympathetic innervation of BAT increased 7- to 13-fold after birth, and this increase was temporally correlated with the postnatal enhancement of AC responsiveness. 6-hydroxydopamine (6-HDA) treatment of neonates reduced tyrosine hydroxylase levels by greater than 90%. This treatment greatly reduced the perinatal increase in NE- and NaF-stimulated AC and completely abolished the increase in forskolin-Mn(2+)-stimulated activity. However, sympathectomy did not alter the postnatal increase in Gs alpha-specific activity and did not prevent the postnatal reduction in Gs alpha levels. These results demonstrate that the sympathetic innervation of BAT develops fully after birth and is essential for the postnatal increase in the activity of C but not of Gs alpha.

Perinatal changes in the coupling of beta 1- and beta 3 adrenergic receptors to brown fat adenylyl cyclase

The stimulation of adenylyl cyclase by catecholamines in neonatal brown adipose tissue (BAT) is markedly biphasic, suggesting the existence of receptors that have both high and low affinities for catecholamines. The identities of these receptors were examined by comparing responses in neonatal BAT membranes to those of Chinese hamster ovary cells which had been transfected to express the cloned rat beta 1 and beta 3 receptors. The results from these experiments indicate that high-affinity stimulation of adenylyl cyclase by catecholamines in BAT is mediated by beta 1 receptors, as evidenced by the potencies of norepinephrine and isoproterenol at this receptor and the potent blockade of the receptor by alprenolol. The low-affinity catecholamine receptor appears to be the beta 3 receptor, as indicated by the low potency of catecholamine agonists and the inability of low concentrations of alprenolol to block this activity. Furthermore, this receptor, like the cloned rat beta 3 receptor, was antagonized by (-)-4-(3-t-butylamino-2-hydroxypropoxy)benzimidazol-2-one (CGP 12177) and was stimulated by (R',R')-4-(2-[(2[(3-chlorophenyl)-2- hydroxyethyl]amino)propyl]phenyl)phenoxyacetic acid (BRL 37344). These results indicate that both beta 1 and beta 3 receptors couple to adenylyl cyclase in BAT and that activation of adenylyl cyclase in neonatal BAT is mediated primarily by beta 3 receptors. Beta 3 receptors were also clearly detected in weanling BAT with the beta 3-selective agonist BRL 37344. However, when catecholamines were used to stimulate activity, the activation of adenylyl cyclase by beta 1 receptors, which occurred at low concentrations of catecholamines, obscured the activation of adenylyl cyclase by beta 3 receptors, which occurred only at high concentrations.

Expression of platelet-derived growth factor and its receptors in neuroendocrine tumors of the digestive system

Carcinoid tumors are slowly growing neuroendocrine neoplasms which often present pronounced fibrosis around the tumor cells. We have previously shown by immunohistochemistry that carcinoid tumors express platelet-derived growth factor (PDGF) beta-receptors on surrounding stromal cells. In this report, 22 midgut carcinoids and 5 endocrine pancreatic tumors were examined for the presence of PDGF with a monoclonal antibody raised against a peptide corresponding to a part of the B-chain of PDGF which reacts strongly with the B-chain and weakly with the A-chain. They were also examined for PDGF alpha-receptors with an affinity-purified polyclonal peptide antibody and for PDGF beta-receptor with the monoclonal antibody PDGFR-B2. PDGF was expressed on tumor cells and on adjacent stroma. PDGF alpha-receptor was seen on clusters of tumor cells and occasionally on adjacent stroma, whereas beta-receptors were seen only in the stroma. Tissue sections from some of these midgut carcinoids were also investigated by in situ hybridization for mRNA of PDGF A- and B-chains as well as alpha- and beta-receptors. By in situ hybridization, abundant expression of mRNA for PDGF beta-receptor and PDGF A-chain was observed in stromal cells adjacent to carcinoid tumor cell clusters, but the mRNA expression in the tumor cells themselves was at a low level. A few clustered tumor cells and stromal cells expressed mRNA for the PDGF alpha-receptor, thus consolidating the immunohistochemical findings. mRNA for the PDGF B-chain was detected in both tumor cells and stroma, but only at low levels. Our data suggest that PDGF is involved in the growth stimulation of the carcinoid tumor cells in an autocrine fashion and in the stimulation of stromal cell growth through paracrine and possibly autocrine mechanisms. Moreover, remarkably strong immunostaining of PDGF and the PDGF alpha-receptor was seen on peripheral nerve fibers.

A study of biological behavior based on the expression of a proliferating antigen in neuroendocrine tumors of the digestive system

The expression of a proliferating antigen by Ki-67 immunohistochemistry was evaluated in 32 gastrointestinal carcinoids and in 5 pancreatic islet cell tumors. In the tissue sections the number of labelled nuclei was calculated per tumor area. The tumors were classified as low proliferating (less than 0.3 labelled cells/mm2), medium proliferating (0.3-1 labelled cells/mm2), and high proliferating (greater than 1 labelled cell/mm2). In 26 tumors obtained from patients receiving antitumor therapy (alpha-interferon) the proliferative activity was decreased. In treated midgut carcinoids the proliferative activity in metastatic tissue was significantly reduced (p less than 0.05). Though not statistically significant, primary midgut carcinoids collected from untreated patients displayed a lower proliferative activity than liver metastases. A survival analysis revealed that patients with tumors displaying low proliferative activity had a better survival than those with high proliferative activity (p less than 0.05). Single cell cytofluorometric DNA analyses showed regular diploid stem cell lines in the majority of tumors from untreated patients (9/11 cases). No correlation was found between the calculated proliferative activity and the DNA profile. The obtained results indicate that the expression of a proliferation antigen by Ki-67 immunohistochemistry can be used to evaluate the biological behavior of neuroendocrine tumors of the digestive system and predict survival.

Molecular cloning and expression of the rat beta 3-adrenergic receptor

Rat adipose tissues contain atypical beta receptors that display certain pharmacological sensitivities that are similar to those found in the recently cloned human beta 3 receptor. However, there are also certain pharmacological differences between the human atypical beta 3 receptor and atypical receptors in rodent adipose tissues, which could indicate strong species differences, the existence of multiple atypical receptor subtypes, or both. To help decide among these possibilities, a rat beta 3 receptor clone was obtained and expressed in Chinese hamster ovary cells. The predicted primary structures of the rat and human receptors are greater than 90% similar. Despite this similarity, the pharmacological properties of the rat receptor differed from those reported for the human receptor but were similar to the properties exhibited by atypical receptors in rat adipose tissue. Specifically, the rat beta 3 receptor had a high affinity for BRL 37344 and a relatively low affinity for norepinephrine and was partially activated by the beta 1 and beta 2 receptor antagonist CGP 12177. Northern blot analysis and nuclease protection assays of RNA from rat tissues indicate that the beta 3 receptor is abundantly expressed only in adipose tissues.

Characterization of circulating lymphocytes by monoclonal antibodies in childhood and adult leprosy

Peripheral blood lymphocyte assays using monoclonal antibodies were done in 66 patients with leprosy, consisting of 25 children and 41 adults. The results were statistically analyzed for correlations, if any, among the different age groups and matched controls. The results, however, failed to show any significant correlation, nor was it possible to draw any conclusion as to why the disease spectrum in children tends to be incomplete (ie, there is a low incidence of the highly bacilliferous form of disease expression).