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Conformational effects on retinoid receptor selectivity. 2. Effects of retinoid bridging group on retinoid X receptor activity and selectivity.

The natural retinoid 9-cis-retinoic acid is an activating ligand for both the retinoic acid receptors (RARs) and the retinoid X receptors (RXRs), which are members of the retinoid/thyroid hormone/steroid hormone family of nuclear receptor proteins that activate gene transcription through specific response elements. The pharmacophoric groups necessary to confer RXR selectivity were established by evaluating the ability of 21 conformationally restricted retinoids to activate the TREpal retinoic acid receptor response element for gene transcription in the presence of one of the three RAR subtypes or RXR alpha. In contrast to those retinoids selective for the RARs, these RXR-selective retinoids have one less atom in the bridge linking the hydrophobic and carboxylic acid termini of the retinoid skeleton. Therefore, a one-carbon bridge replaces the 19-methyl group and 9E-double bond of 9-cis-retinoic acid and is further functionalized by inclusion in an isopropylidene group, a dioxolane ring, or a cyclopropane ring for optimal RXR alpha activity and selectivity. In addition, the beta-geranylidene and 20-methyl-(11E,13E)-dienoic acid groups of 9-cis-retinoic acid are replaced by a 5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl ring and a 4-carboxylphenyl ring, respectively, for optimal activation and selectivity. RXR alpha selectivity is reduced on replacement of the 4-carboxylphenyl group by a 2-carboxyl-5-thienyl group or the 9-cis-retinoic acid methylpentadienoic acid terminus.

Cell Line↗

Selective inhibitors of Candida albicans dihydrofolate reductase: activity and selectivity of 5-(arylthio)-2,4-diaminoquinazolines.

The recent increase in fungal infections, especially among AIDS patients, has resulted in the need for more effective antifungal agents. In our search for such agents, we focused on developing compounds which inhibit fungal dihydrofolate reductase (DHFR). A series of 25 5-(arylthio)-2,4-diaminoquinazolines were synthesized as potentially selective inhibitors of Candida albicans DHFR. The majority of the compounds were potent inhibitors of C. albicans DHFR and much less active against human DHFR. High selectivity, as defined by the ratio of the I50 values for human and C. albicans DHFR, was achieved by compounds with bulky and rigid 4-substituents in the phenylthio moiety. For example, 5-[(4-morpholinophenyl)thio]-2,4-diaminoquinazoline displayed a selectivity ratio of 540 and was the most selective inhibitor synthesized to date. Substitution in the 2- or 3-position of the 5-phenylthio group provided only marginal selectivity. 6-Substituted-5-[(4-tert-butylphenyl)thio]-2,4-diaminoquinazolines showed potent activity against the C. albicans enzyme but were equally active against human DHFR. Most of the selective compounds were also good inhibitors of C. albicans cell growth, with minimum inhibitory concentration values as low as 0.05 microgram/ mL.

Animals↗

Hypoxia-selective antitumor agents. 9. Structure-activity relationships for hypoxia-selective cytotoxicity among analogues of 5-[N,N-bis(2-chloroethyl)amino]-2,4-dinitrobenzamide.

A series of analogues of the novel hypoxia-selective cytotoxin 5-[N,N-bis(2-chloroethyl)amino]-2,4-dinitrobenzamide (6) have been prepared and evaluated, in a search for compounds which retain high hypoxic selectivity but have increased potency and/or aqueous solubility. Several analogues with ionizable or dipolar carboxamide side chains showed improved solubility but generally had reduced cytotoxic potency and hypoxic selectivity. Modification of the mustard leaving groups or replacement of the carboxamide moiety provided some compounds with superior potency, but only the mixed chloro/mesylate mustard 20 provided a gain in potency relative to solubility while retaining the hypoxic selectivity of 6. These nitrogen mustards did not show the remarkable activity demonstrated by the related aziridine 7 [CB 1954, 5-(N-aziridinyl)- 2,4-dinitrobenzamide] in Walker 256 adenocarcinoma cells and are not efficient substrates for the DT-diaphorase which activates the latter compound by aerobic nitroreduction in Walker cells. Variations in hypoxic selectivity within the dinitrobenzamide mustards appear not to be due to differences in sensitivity to activation by this enzyme. Walker cells showed intermediate sensitivity to the mono(2-chloroethyl) analogue 26 but not to the related half-mustard 27, suggesting that the inhibition of DT-diaphorase activity is due to steric effects in the 5-position. The preferred compound overall with respect to solubility, potency, and in vitro hypoxic cell selectivity was the (dimethylamino)-ethyl derivative 11. DNA elution studies and comparison of the sensitivity of AA8 and UV4 cells to this compound indicated reductive activation to form a DNA cross-linking agent under hypoxia. Radiobiological studies indicated 11 to be equally active against both aerobic and hypoxic cells in KHT tumors. It is not clear whether this reflects efficient killing of aerobic cells as a result of diffusion of reduced metabolites from hypoxic regions or whether cytotoxicity in tumors is independent of hypoxia.

Aniline Mustard↗

Hypoxia-selective antitumor agents. 14. Synthesis and hypoxic cell cytotoxicity of regioisomers of the hypoxia-selective cytotoxin 5-[N,N-bis(2-chloroethyl)amino]-2,4-dinitrobenzamide.

A series of regioisomers of the novel hypoxia-selective cytotoxin (HSC) 5-[N,N-bis(2-chloroethyl)-amino]-2,4-dinitrobenzamide (2a) have been prepared by displacement of the chloro group from methyl chlorodinitrobenzoates or the corresponding carboxamides with diethanolamine, followed by dimesylation and mesylate displacement with LiCl. The compounds fall into two classes, where the two nitro groups have either a meta or an ortho (or para) disposition to each other. The four meta derivatives had one-electron reduction potentials in the range -340 to -375 mV, similar to that of the known isomer 2a, while the other isomers had much higher values (-262 to -285 mV). The meta derivatives were much less cytotoxic to AA8 cells under aerobic conditions (IC50s from 75 to 470 microM) than were the other compounds (IC50s from 1.6 to 20 microM). However, the ratios of IC50s of the compounds in repair-proficient (AA8) and repair-deficient (UV4) cell lines varied, indicating differing contributions of DNA alkylation to aerobic toxicity between the isomers, with no clear relationship between this and nitro group disposition. The hypoxic selectivities of the (dimethylamino)ethylcarboxamide analogues for each isomer were determined by clonogenic assay against both AA8 and UV4 cells. With one exception, the meta derivatives showed excellent hypoxic selectivities (ca. 45-115-fold) against UV4 cells, while the ortho or para isomers had little selectivity (ca. 2-7-fold). A possible reason may be that the latter compounds, with higher reduction potentials, undergo rapid bioreduction even under aerobic conditions. None showed hypoxic selectivities greater than 2-3-fold against AA8 cells. The 3-[N,N-bis(2-chloroethyl)amino]-2,6-dinitrobenzamide isomer (5b), which showed the highest hypoxic selectivity for UV4 cells in this series, was active against both hypoxic and aerobic cells in KHT tumors in mice at well-tolerated doses, and showed superior in vivo activity to the previously studied 2,4-dinitro isomer 2b.

Aniline Mustard↗

Highly selective, novel analogs of 4-[2-(diphenylmethoxy)ethyl]- 1-benzylpiperidine for the dopamine transporter: effect of different aromatic substitutions on their affinity and selectivity.

Several analogs of the potent and selective dopamine transporter (DAT) ligand 4-[2-(diphenylmethoxy)ethyl]-1-benzylpiperidine, 1a, were prepared and biologically evaluated at the dopamine and serotonin transporter (SERT) sites. Several substituents were introduced in the aromatic rings to evaluate the influences of electronic and steric interactions in their binding to the DAT. All the novel analogs showed preferential interaction at the DAT compared with the SERT. Different aromatic substitutions in the phenyl ring of the N-benzyl part of the molecule played a key role in the selectivity. In general, compounds with strong electron-withdrawing substituents were most active and selective at the DAT. Thus, compounds 5a (R = F) and 11b (R = NO2) were among the most potent (IC50 = 17.2 and 16.4 nM, respectively) and most selective (SERT/DAT = 112 and 108, respectively) and were far more selective than GBR 12909 (SERT/DAT = 6). Bioisosteric replacement of one of the phenyl rings of the diphenylmethoxy moiety by a thiophene ring was tolerated well and produced the most potent compound 13b (IC50 = 13.8 nM) in the series. Our current structure-activity studies of these piperidine analogs resulted in the generation of second generation of GBR-type compounds, and all of these new compounds reported here were more selective than GBR 12909 in interacting with the DAT over the SERT.

Animals↗

1-(3-Cyanobenzylpiperidin-4-yl)-5-methyl-4-phenyl-1, 3-dihydroimidazol-2-one: a selective high-affinity antagonist for the human dopamine D(4) receptor with excellent selectivity over ion channels.

After the requirement of pseudocycle formation in the ureas 3 and 7 for hD(4) binding and selectivity was confirmed, structural hybridization with the known hD(4) ligand 2 led to the design and identification of the lead 4-(2-oxo-1, 3-dihydroimidazol-2-yl)piperidine 8. Optimization studies were carried out on 8 with the aim of achieving 1000-fold selectivity for hD(4) over all other receptors while retaining the good pharmacokinetic properties of the lead. After initial preparation of 8 as a minor component in a low-yielding reaction, a novel and regioselective "four-step/one-pot" procedure was developed which proved to be applicable to rapid investigation of the SAR of the 1, 3-dihydroimidazol-2-one ring. Various changes to substituents attached to the 3-, 4-, or 5-position of the 1, 3-dihydroimidazol-2-one core of 8 did not significantly improve selectivity for hD(4) over hD(2) and hD(3). Greater selectivity (>1000-fold) was ultimately achieved by meta substitution of the benzyl group of 8 with various substituents. Compounds 28, 31, and 32 all possess the required selectivity for hD(4) over the other dopamine subtypes, but only 32 has >1000-fold selectivity over all the key counterscreens we tested against. Compound 32 is an antagonist at hD(4) and has a good pharmacokinetic profile in the rat, with excellent estimated in vivo receptor occupancy, thus making it a potentially useful pharmacological tool to investigate the role of the D(4) receptor.

Animals↗

Selective stopping in task switching: The role of response selection and response execution.

Recently, several studies stressed the role of response selection in cued task switching. The present study tried to investigate directly the hypothesis that no switch cost can be found when there was no response selection. In two experiments, we combined a cued task switching paradigm with the selective stopping paradigm. Results of the experiments demonstrated that a switch cost was found when participants selected a response, even without response execution. Alternatively, when the response was inhibited without the need of response selection, no switch cost was found. These results provide direct evidence for the distinct role of response selection in cued task switching and suggest that response execution is not a necessary factor to obtain a switch cost.

Choice Behavior↗

CD45 enhances positive selection and is expressed at a high level in large, cycling, positively selected CD4+CD8+ thymocytes.

T-cell development is arrested at the CD4+CD8+ (DP; double-positive) stage of thymocyte development in CD45 null mice. However, the mechanism by which CD45 participates in the positive selection of T cells remains to be investigated. In this report we describe a DP thymocyte population that associates positive selection with expression of high levels of CD45, CD4 and CD8. DP thymocytes of this phenotype are large, cycling cells and represent approximately 20% of DP thymocytes in normal mice. In mice expressing a transgenic T-cell receptor (TCR) specific for the male antigen presented by H-2Db (H-Y TCR), the up-regulation of TCR, CD5 and CD69 in this large DP population occurred in a major histocompatibility complex (MHC)-restricted manner. To investigate further the role of CD45 in positive selection, we determined whether thymocytes that expressed a transgenic CD45RO molecule under the control of the proximal lck promoter can influence the positive selection of T cells in H-Y TCR transgenic mice. It was found that in female H-Y TCR transgenic mice, MHC-restricted positive selection of CD4- CD8+ H-Y TCR+ thymocytes was enhanced by increased CD45RO expression. Thus, CD45 increases the efficacy of positive selection of CD4- CD8+ thymocytes that express H-Y TCR.

Animals↗

Comparison of selective and non-selective enrichment media in the detection of Listeria monocytogenes from meat containing Listeria innocua.

AIMS: This study investigated whether the higher incidence of recovery from meat of Listeria innocua compared with L. monocytogenes could be due to the laboratory media used, leading to an artificially lower detection of the pathogenic species, L. monocytogenes. METHODS AND RESULTS: Minced beef was inoculated with L. monocytogenes, L. innocua, or a mixture of these species, and stored at 0 or 10 degrees C under vacuum or aerobic conditions for up to 28 days. Listeria were recovered from the minced beef using selective (University of Vermont Medium, UVM) and non-selective (Buffered Peptone Water, BPW) enrichment broths after 0, 14, and 28 days of storage. In general, there were no significant differences (P < 0.05) between the numbers of L. monocytogenes recovered from minced beef samples after 24 h enrichment in BPW and the numbers recovered using UVM. In addition, the presence of L. innocua in meat samples containing L. monocytogenes did not significantly (P < 0.05) affect the numbers of L. monocytogenes recovered using either enrichment broth. In most cases there were no significant differences (P < 0.05) between the numbers of L. innocua recovered from minced beef samples after 24 h enrichment in BPW compared with numbers recovered using UVM. CONCLUSION: Listeria innocua was found to have no significant competitive advantage over L. monocytogenes in selective or non-selective enrichment media. SIGNIFICANCE AND IMPACT OF THE STUDY: The results suggest that, in some instances, the use of a selective enrichment broth offers no advantage over a non-selective enrichment broth for the recovery of Listeria species from minced beef.

Bacterial Typing Techniques↗

A novel diacylglycerol-lactone shows marked selectivity in vitro among C1 domains of protein kinase C (PKC) isoforms alpha and delta as well as selectivity for RasGRP compared with PKCalpha.

Although multiple natural products are potent ligands for the diacylglycerol binding C1 domain of protein kinase C (PKC), RasGRP, and related targets, the high conservation of C1 domains has impeded the development of selective ligands. We characterized here a diacylglycerol-lactone, 130C037, emerging from a combinatorial chemical synthetic strategy, which showed substantial selectivity. 130C037 gave shallow binding curves for PKC isoforms alpha, beta, gamma, delta, and epsilon, with apparent Ki values ranging from 340 nm for PKCalpha to 29 nm for PKCepsilon. When binding to isolated C1 domains of PKCalpha and -delta, 130C037 showed good affinity (Ki= 1.78 nm) only for deltaC1b, whereas phorbol 12,13-dibutyrate showed affinities within 10-fold for all. In LNCaP cells, 130C037 likewise selectively induced membrane translocation of deltaC1b. 130C037 bound intact RasGRP1 and RasGRP3 with Ki values of 3.5 and 3.8 nm, respectively, reflecting 8- and 90-fold selectivity relative to PKCepsilon and PKCalpha. By Western blot of Chinese hamster ovary cells, 130C037 selectively induced loss from the cytosol of RasGRP3 (ED50 = 286 nm), partial reduction of PKCepsilon (ED50 > 10 microm), and no effect on PKCalpha. As determined by confocal microscopy in LNCaP cells, 130C037 caused rapid translocation of RasGRP3, limited slow translocation of PKCepsilon, and no translocation of PKCalpha. Finally, 130C037 induced Erk phosphorylation in HEK-293 cells ectopically expressing RasGRP3 but not in control cells, whereas phorbol ester induced phosphorylation in both. The properties of 130C037 provide strong proof of principle for the feasibility of developing ligands with selectivity among C1 domain-containing therapeutic targets.

Animals↗

Selection of cytotoxic T-cell precursors specific for minor histocompatibility determinants. I. Negative selection across H-2 barriers induced with disrupted cells but not with glutaraldehyde-treated cells: evidence for antigen processing.

Intravenous injection of CBA mice with H-2-compatible irradiated B10.BR spleen cells led to a sequence of negative and positive selection of the host T-cell response against the multiple foreign minor histocompatibility antigens (HA) on the injected cells. By 1 d posttransfer, thoracic duct lymphocytes (TDL) of the host had lost the capacity to differentiate in vitro into cytotoxic cells specific for the injected minor HA; spleen and lymph node cells, by contrast, gave normal or enriched responses at this time. By 5 d posttransfer, TDL were hyperresponsive to the injected antigens. Selection with disrupted (sonicated) cells gave similar findings. With injection of either irradiated of disrupted spleen cells, the H-2 haplotype of the minor HA-bearing cells had no apparent effect on the magnitude of selection. By contrast, treatment of spleen cells with glutaraldehyde before injection led to H-2 restriction of selection, i.e., negative selection of the CBA response to B10.BR was marked with injection of glutaraldehyde-treated H-2-compatible B10.BR cells but was minimal with H-2-different B10 or B10.D2 cells. These data are taken to imply that, at least in H-2-incompatible situations, the minor HA-bearing cells must be processed by host cells, i.e., to allow the antigens to become associated with self H-2 determinants. Circumstantial evidence from studies on the specificity of selection induced with glutaraldehyde-treated cells from mice of the B10 recombinant strains suggested that I region-restricted T cells may control the induction of H2K, D-restricted cytotoxic precursor cells.

Animals↗

CD34+ cell selection from frozen cord blood products using the Isolex 300i and CliniMACS CD34 selection devices.

Ex vivo expansion of cord blood (CB) cells requires CD34+ cell selection before expansion to obtain optimal numbers of progenitor cells. As a preliminary step to preclinical development of CB expansion, we have evaluated two clinical scale selection devices, the Isolex 300i (Baxter Healthcare, Immunotherapy Division) and the CliniMACS (Miltenyi Biotech Inc.), for CD34+ cell selection from frozen CB products. As expansion of CB results in differentiation of cells, there may be a depletion of stem cells. Therefore, only a fraction of the CB should be expanded while a portion of the CB is maintained unmanipulated for infusion. After thawing of 40% fractions of each CB product, we observed >95% viable cells, with a median total WBC count of 1.8 x 10(8) cells. Use of the Isolex 300i resulted in a median purity of 51% CD34+ cells (n=8) and a median recovery of 34% CD34+ cells. Use of the CliniMACS resulted in a median purity of 54% CD34+ cells (n=10) and a median recovery of 80% CD34+ cells. The absolute number of CD34+ cells recovered after selection varied with samples from 6.7 x 10(4) to 3.2 x 10(6) CD34+ cells. Expansion of CD34+ cells from both systems resulted in >20-fold expansion of CFU-GM, with a median of 44-fold expansion. These data demonstrate the feasibility of selecting small fractions of frozen CB products using clinical scale CD34+ cell selection devices.

Antigens, CD34↗

Selecting among competing alternatives: selection and retrieval in the left inferior frontal gyrus.

It has been widely argued that the left inferior frontal gyrus (LIFG) is involved in the control of retrieval of information from long-term memory. Recent claims that the LIFG is involved in selecting among semantic alternatives have been challenged on the grounds that the manipulation of selection demands may have been confounded with controlled retrieval. The current study used an event-related functional magnetic resonance paradigm to re-examine the possibility that LIFG activation is involved in selection processes. In order to minimize potential confounding effects of controlled retrieval, we used an automatic retrieval task (picture naming) and held retrieval demands constant, while varying selection demands by way of competitor priming from earlier semantically related trials. We found significant activation in LIFG as a function of increased selection demands; activation centred on two peaks, one in anterior LIFG and a second more superior and posterior region. These data support the view that LIFG plays a role in selection among semantic information, even in the absence of controlled retrieval processes.

Adult↗

Plasticity in the positive selection of T cells: affinity of the selecting antigen and IL-7 affect T cell responsiveness.

The current study examines how responsiveness of T cells is affected by the avidity of the peptide/MHC engaged during positive selection of their thymocyte precursors. We used a thymus reaggregate culture system in which CD4(+)CD8(+) thymocytes from AND TCR transgenic mice were induced to undergo positive selection by pigeon cytochrome c (PCC) peptide or its analogs presented by I-E(k) class II MHC on a thymic epithelial cell line. When low-affinity peptide analogs drove positive selection, up to 100 microM was needed to produce >50% CD4(+) T cells, and these cells were highly responsive to PCC. In contrast, <0.2 microM high-affinity peptides was required to achieve similar selection efficiency, but the resultant cells failed to respond to PCC. However, these cells were not dead based on dye exclusion and capacity to respond to phorbal ester and to agonist if IL-2 was also present, supporting the view that non-responsiveness of cells selected on high-affinity peptides is a form of central T cell tolerance distinct from deletion. Cells selected on intermediate-affinity peptides showed variable responsiveness which was suppressed 5- to 10-fold by addition during reaggregate culture of antibody to the IL-7R. Similarly, supplementary IL-7 in the reaggregate culture produced CD4(+) T cells that were promiscuously responsive. Overall, this study demonstrates that the responsiveness of T cells is not rigidly controlled and that the presence of IL-7 during T cell development has the potential to negate central T cell tolerance and produce autoreactive T cells.

Animals↗

Quantitative trait locus mapping in chickens by selective DNA pooling with dinucleotide microsatellite markers by using purified DNA and fresh or frozen red blood cells as applied to marker-assisted selection.

Many large, half-sib sire families are an integral component of chicken genetic improvement programs. These family structures include a sufficient number of individuals for mapping quantitative trait loci (QTL) at high statistical power. However, realizing this statistical power through individual or selective genotyping is yet too costly to be feasible under current genotyping methodologies. Genotyping costs can be greatly reduced through selective DNA pooling, involving densitometric estimates of marker allele frequencies in pooled DNA samples. When using dinucleotide microsatellite markers, however, such estimates are often confounded by overlapping "shadow" bands and can be confounded further by differential amplification of alleles. In the present study a shadow correction procedure provided accurate densitometric estimates of allele frequency for dinucleotide microsatellite markers in pools made from chicken purified DNA samples, fresh blood samples, and frozen-thawed blood samples. In a retrospective study, selective DNA pooling with thawed blood samples successfully identified two QTL previously shown by selective genotyping to affect resistance in chickens to Marek's disease. It is proposed that use of selective DNA pooling can provide relatively low-cost mapping and use in marker-assisted selection of QTL that affect production traits in chickens.

Alleles↗

Selective inhibitors of cyclooxygenase-2: are they really effective, selective, and GI-safe?

Selective inhibitors of the "inducible" isoform of cyclooxygenase (COX-2) have been suggested to be effective analgesic and anti-inflammatory drugs while sparing the gastrointestinal (GI) tract of injury. There is some experimental and early clinical evidence to support this hypothesis. However, some important questions remain regarding the utility of selective COX-2 inhibitors. For example, estimates of the selectivity of COX-2 inhibitors based on in vitro studies are likely to be poor predictors of selectivity in vivo. Efficacy with selective blockade of COX-2 may be inferior to that achieved with combined inhibition of COX-1 and COX-2. Furthermore, in situations in which there is inflammation or ulceration in the GI tract, COX-2 produces prostaglandins that are essential for repair. In these circumstances, inhibition of COX-2 leads to delay of ulcer healing and exacerbation of inflammation. Some caution should therefore be exercised before the theory is fully accepted that selective COX-2 inhibitors are effective anti-inflammatory drugs that spare the GI tract of injury.

Analgesics↗

The difference between non-selective and beta 1-selective beta-blockers in their effect on platelet function in migraine patients.

Platelet function has been postulated as playing a role in the pathogenesis of migraine. This study aimed to investigate to what extent beta 1-selective and non-selective beta-blockers interfere with the platelet function in migraine patients. Twelve patients with classical migraine were included. After a 2-week drug-free period, the patients were randomly allocated to either beta 1-selective metoprolol (50 mg b.i.d.) or non-selective propranolol (40 mg b.i.d.) treatment for one month. After a wash-out period, the patients were changed to the corresponding beta-blocker for one month. ADP-induced platelet aggregability, platelet cAMP, ATP and ADP levels, plasma cAMP and TxB2 concentration, as well as the serum production of TxB2 were measured before and after each treatment period. After propranolol treatment, the patients showed lower ADP threshold values for producing irreversible platelet aggregation and lower platelet and plasma cAMP levels as compared to metoprolol. Neither of the beta-blockers induced any change in the plasma concentration or serum production of TxB2. In conclusion, non-selective beta-blockade (propranolol) significantly increases the platelet aggregability compared to beta 1-selective blockade (metoprolol).

Adenosine Diphosphate↗

Effects of truncal, selective, and highly selective vagotomy on glucose tolerance and insulin secretion in patients with duodenal ulcer. Part I-Effect of vagotomy on response to oral glucose.

An oral glucose tolerance test was performed in patients who had undergone truncal vagotomy and pyloroplasty, bilateral selective vagotomy and pyloroplasty, or highly selective vagotomy without a drainage procedure at least six months earlier. The results were compared with those from patients with chronic duodenal ulcer before operation. In all three groups of patients after vagotomy more rapid rates of rise of blood glucose and higher peak concentrations were observed than in patients who were tested before operation. These differences were statistically significant only in patients who had undergone truncal or selective vagotomy with pyloroplasty and were probably due to more rapid rates of gastric emptying after these operations. Plasma insulin concentrations were lower after truncal vagotomy than after selective or highly selective vagotomy, the difference between truncal vagotomy and highly selective vagotomy being statistically significant. Truncal vagotomy resulted in a diminished insulin response to oral glucose, which could have been due to vagal denervation of the pancreas or, more probably, impaired release of small-bowel hormones which normally augment the pancreatic insulin response.

Adult↗