Trastuzumab-Emtansine and Osimertinib Combination Therapy to Target HER2 Bypass Track Resistance in EGFR Mutation-Positive NSCLC.

Introduction: EGFR tyrosine kinase inhibitor improved the survival of patients with metastatic EGFR mutation-positive (EGFRm+) NSCLC. Despite high response rates, resistance develops inevitably in every patient. In up to 13%, HER2 protein overexpression is found on progression. We hypothesized that dual blockade of EGFR and HER2 by osimertinib combined with trastuzumab-emtansine (T-DM1) could reinduce tumor responses. Methods: In this multicenter, single-arm, phase 1-2 study (NCT03784599), patients with EGFRm+ NSCLC, progressing on osimertinib and HER2 overexpression were included. Patients were treated with T-DM1 3.6 mg/kg (intravenously) every 3 weeks and osimertinib 80 mg once a day. Primary end points were objective response rate (ORR) at 12 weeks and safety. Responses were assessed every 6 weeks (Response Evaluation Criteria in Solid Tumors 1.1). Sample size was calculated using Simon's two-stage minimax design (H0 = 41%, H1 > 55%, 80% power, one-sided type I error 10%: a ORR 16 of 36 was needed to proceed to 58 patients). Results: From January 2019 to April 2021, 27 patients were enrolled. ORR after 12 weeks of treatment was 4% (1 of 27). Median progression-free survival was 2.8 months (95% confidence interval: 1.4-4.6 mo). Most frequent treatment-related adverse events of any grade were fatigue, diarrhea, and nausea, among these, grade 3 in four patients. There were no grade 4 or 5 therapy-related adverse events. Conclusions: TRAEMOS (Trastuzumab-Emtansine and Osimertinib) is the first trial combining T-DM1 and osimertinib in patients with EGFRm+ NSCLC to target HER2 overexpression at osimertinib resistance. Safety profile was favorable compared with cytotoxic chemotherapy; but treatment revealed limited efficacy. Further clinical evaluation of this regimen is not warranted.

Trastuzumab and pertuzumab combination therapy for advanced pre-treated HER2 exon 20-mutated non-small cell lung cancer.

INTRODUCTION: In 1-3% of non-small cell lung cancer (NSCLC) human epidermal growth factor 2 (HER2) mutations are identified as a genomic driver. Nevertheless, no HER2-targeted treatment is approved for NSCLC. In the Drug Rediscovery Protocol (DRUP), patients are treated with off-label drugs based on their molecular profile. Here, we present the results of the cohort 'trastuzumab/pertuzumab for HER2 exon20 mutation positive (HER2m+) NSCLC'. METHODS: Patients with treatment refractory, advanced HER2m+ NSCLC with measurable disease (RECISTv1.1) were eligible. Treatment with intravenous trastuzumab combined with pertuzumab every 3 weeks was administered. The primary end-point was clinical benefit (CB: either objective response or stable disease ≥ 16 weeks). Patients were enrolled using a Simon-like 2-stage design, with 8 patients in stage 1 and up to 24 patients in stage 2 if at least 1 patient had CB in stage 1. At baseline, a biopsy for biomarker analysis, including whole genome sequencing, was obtained. RESULTS: Twenty-four evaluable patients were enrolled and treated between May 2017 and August 2020. CB was observed in 9 patients (38%); including an objective response rate of 8.3% (2 patients had a partial response) and 7 patients with stable disease ≥ 16 weeks. The most frequently observed HER2 mutation was p.Y772_A775dup (71%, n = 20). Median follow-up was 13 months, median progression-free survival and overall survival 4 (95% CI 3-6) and 10 months (95% CI 4 - not reached), respectively. Whole genome sequencing data (available for 67% of patients) confirmed the inclusion mutation in all cases. No unexpected toxicity was observed. CONCLUSION: Despite the fact that the study did meet its primary end-point, trastuzumab/pertuzumab was only marginally active in a subset of patients with heavily pre-treated HER2m+ NSCLC.

The force of HER2 - A druggable target in NSCLC?

Since several years targeted therapy has been part of treatment in NSCLC in subsets of patients with specific genetic alterations. One of these alterations involves HER2, a member of the ERBB family of tyrosine kinase receptors. Despite that HER2 alterations in NSCLC have been studied for years, there is still no consensus about subgroup definitions. In this review HER2 alterations in NSCLC are discussed, including diagnostic challenges and treatment strategies. Three principal mechanisms of HER2 alterations can be identified: HER2 protein overexpression, HER2 gene amplification and HER2 gene mutations. There are several methods for the detection of HER2 "positivity" in NSCLC, but no gold standard has been established. Laboratory methods for assessment of HER2 positivity in NSCLC include immunohistochemistry (IHC) for protein overexpression and fluorescent in situ hybridization (FISH) and next generation sequencing (NGS) for genetic alterations. Many trials testing HER2 targeted therapy in HER2 altered NSCLC has not lead to a renewed standard of care for this group of patients. Therefore, today the (re)search on how to analyse, define and treat HER2 alterations in NSCLC continues. Still there is no consensus about HER2 subgroup definitions and results of the many trials studying possible treatment strategies are inconclusive. Future research should focus on the most important missing link, whether all HER2 alterations are relevant oncogenic drivers and whether it should be considered as a therapeutic target in NSCLC.

Trastuzumab and paclitaxel in patients with EGFR mutated NSCLC that express HER2 after progression on EGFR TKI treatment.

BACKGROUND: HER2 expression and amplification are observed in ~15% of tumour biopsies from patients with a sensitising EGFR mutation who develop EGFR TKI resistance. It is unknown whether HER2 targeting in this setting can result in tumour responses. METHODS: A single arm phase II study was performed to study the safety and efficacy of trastuzumab and paclitaxel treatment in patients with a sensitising EGFR mutation who show HER2 expression in a tumour biopsy (IHC ≥ 1) after progression on EGFR TKI treatment. Trastuzumab (first dose 4 mg/kg, thereafter 2 mg/kg) and paclitaxel (60 mg/m2) were dosed weekly until disease progression or unacceptable toxicity. The primary end-point was tumour response rate according to RECIST v1.1. RESULTS: Twenty-four patients were enrolled. Nine patients were exon 21 L858R positive and fifteen exon 19 del positive. Median HER2 IHC was 2+ (range 1-3). For 21 patients, gene copy number by in situ hybridisation could be calculated: 5 copies/nucleus (n = 9), 5-10 copies (n = 8), and >10 copies (n = 4). An objective response was observed in 11/24 (46%) patients. Highest response rates were seen for patients with 3+ HER2 IHC (12 patients, ORR 67%) or HER2 copy number ≥10 (4 patients, ORR 100%). Median tumour change in size was 42% decrease (range -100% to +53%). Median duration of response was 5.6 (95% confidence interval [CI], 3.8 to 7.3) months. Treatment toxicity was mild with four patients experiencing grade ≥3 toxicity, including fatigue, neuropathy, neutropaenia, urinary tract infection, and pneumonitis. CONCLUSIONS: Trastuzumab-paclitaxel induces objective tumour responses in 46% of EGFR TKI pretreated patients with an activating EGFR mutation and HER2 expression. The treatment was well tolerated. The relation between response rate and HER2 expression level and copy number suggests effective HER2 targeting by trastuzumab, although the combination with paclitaxel does not allow to determine the relative contribution of the individual drugs in terms of treatment efficacy.

The prognostic value of the neoadjuvant response index in triple-negative breast cancer: validation and comparison with pathological complete response as outcome measure.

The Neoadjuvant response index (NRI) has been proposed as a simple measure of downstaging by neoadjuvant treatment in breast cancer. It was previously found to predict recurrence-free survival (RFS) in triple-negative (TN) breast cancer. It was at least as accurate as the standard binary system, the absence or presence of a pathological complete remission (pCR), which is the commonly employed outcome measure. The NRI was evaluated in an independent consecutive series of patients to validate the previous findings. Univariable and multivariable analyses were done to assess the predictive value of clinical parameters and of the NRI for RFS. We combined the original and validation series of patients to build a multivariable predictive model for RFS after neoadjuvant chemotherapy in TN breast cancer. The validation set (N = 108) confirmed that patients with a higher-than-median NRI (>0.7) had excellent RFS (P = 0.002), similar to that of patients who had achieved a pCR. Multivariable analysis in 191 patients showed that the NRI was a strong independent predictor of RFS (P = 0.0002), with N-stage (P = 0.001) and T-stage (P = 0.014) ranking second and third, respectively. Importantly, among patients who did not achieve a pCR (NRI values below 1), higher NRI values were still associated with better RFS. The NRI is a simple method and a practical tool to predict RFS in TN breast cancer patients treated with neoadjuvant chemotherapy. It adds prognostic information to the presence or absence of pCR and could be useful to compare the efficacies of different chemotherapy regimens.

Selection by AZT and rapid replacement in the absence of drugs of HIV type 1 resistant to multiple nucleoside analogs.

We studied the intrahost evolution and dynamics of a multidrug-resistant HIV-1, which contains an insertion of two amino acids (aa) and several aa changes within the reverse transcriptase (RT) gene. From an individual receiving intermittent therapy, sequences of 231 full-length molecular clones of HIV-1 RT were obtained from serum-derived viruses at 12 consecutive time points over a period of 6 years, 17 to 20 clones per time point. In the 3.5-year period prior to the first course of therapy, only wild-type (wt) viruses were found. As soon as 6 months after the start of zidovudine (AZT) monotherapy, all viruses contained an insertion of two aa between positions 68 and 69 of the RT and aa changes at positions 67 and 215, a combination conferring resistance to multiple nucleoside analogs. After termination of therapy, the insertion mutants were rapidly and completely replaced by the wt viruses. In turn, the insertion mutants replaced the wt viruses after initiation of therapy with 3TC, d4T, and saquinavir. After termination of triple therapy, the wt viruses completely replaced the mutants within 1 month, which is markedly faster than has been observed earlier for the replacement of AZT-resistant viruses. Fast replacements of the mutant virus populations after termination of therapy indicate gross competitive disadvantage of the insertion mutant in the absence of therapy, which we estimated by using several models. The insertion mutants attained high virus loads, demonstrating that virus load cannot be used as a direct measure of virus fitness.

Identification of an active reverse transcriptase enzyme encoded by a human endogenous HERV-K retrovirus.

Of the numerous endogenous retroviral elements that are present in the human genome, the abundant HERV-K family is distinct because several members are transcriptionally active and coding for biologically active proteins. A detailed phylogeny of the HERV-K family based on the partial sequence of the reverse transcriptase (RT) gene revealed a high incidence of an intact RT open reading frame within the HML-2 subgroup of HERV-K elements. In this study, we report the cloning of six full-length HML-2 RT genes, of which five contain an uninterrupted open reading frame. The RT enzymes were expressed as glutathione S-transferase fusion proteins in Escherichia coli, and several HERV-K RT enzymes demonstrated polymerase as well as RNase H activity. Several biochemical properties of the RT polymerase were analyzed, including the template requirements and optimal reaction conditions (temperature, type of divalent cation). Inspection of the nucleotide sequence of the HERV-K RT genes demonstrated a mosaic structure, suggesting that a high level of genetic recombination has occurred in this virus family, which is a hallmark of replication by means of reverse transcription. The selective pressure to maintain the RT coding potential is illustrated by the sequence of a particular HERV-K isolate that contains three 1-nucleotide deletions within a small RT segment, thus maintaining the open reading frame. These combined results may suggest that these endogenous RT enzymes still have a biological function. It is possible that the RT activity was involved in the spread of this major class of retroelements by retrotransposition, and in fact it cannot be excluded that this retrovirus group is still mobile. The endogenous RT activity may also have been involved in the shaping of the human genome, e.g., by formation of pseudogenes.

Biased nucleotide composition of the genome of HERV-K related endogenous retroviruses and its evolutionary implications.

The human genome contains a large number of sequences that belong to the HERV-K family of human endogenous retroviruses. Most of these elements are likely remnants of ancient infections by ancestral exogenous retroviruses. To obtain further insight into the evolutionary history and molecular mechanisms responsible for the diversity of the human HERV-K elements, we analyzed several aspects of their genome structure. The nucleotide composition of the HERV-K genome was found to be highly biased and asymmetric, with an abundance of the A nucleotide in the viral (+) strand. A similar trend has been reported for the genomes of several exogenous retroviruses, with different nucleotides as the preferred building block. Other genome characteristics that were reported previously for actively replicating retroviruses are also apparent for the endogenous HERV-K virus. In particular, we observed suppression of the dinucleotide CpG, which represents potential methylation sites, and a strong preference for synonymous substitutions within the open reading frame of the reverse transcriptase (RT) enzyme. Furthermore, the mutational spectrum of the HERV-K RT enzyme was evaluated by nucleotide sequence comparison of 34 available elements. Interestingly, this analysis revealed a striking similarity with the mutational pattern of the HIV-1 RT enzyme, with a preference for G-to-A and C-to-T transitions. It is proposed that the mutational bias of the HERV-K RT enzyme played a role in the shaping of this retroviral genome, which was actively replicating more than 30 million years ago. This effect can still be observed in the contemporary endogenous HERV-K elements.

Evolutionary relationships within a subgroup of HERV-K-related human endogenous retroviruses.

The prototype endogenous retrovirus HERV-K10 was identified in the human genome by its homology to the exogenous mouse mammary tumour virus. By analysis of a short 244 bp segment of the reverse transcriptase (RT) gene of other HERV-K10-like sequences, it has become clear that these elements represent an extended family consisting of multiple groups (the HML-1 to HML-6 subgroups). Some of these elements are transcriptionally active and contain an intact open reading frame for the RT protein, raising the possibility that this family is still expanding through retrotransposition. To better define the relationship of these endogenous retroviruses, we identified ten new members of the HML-2 subgroup. PCR was used to amplify reverse-transcribed RNA of a 595 bp region of the RT gene in a variety of human cell samples, including normal and leukaemic bone marrow and peripheral blood, placenta cells and a transformed T cell line. We provide an extensive phylogenetic analysis of the relationships for this cluster of HERV-K-related endogenous retroviral elements. Nucleotide diversity values for nonsynonymous versus synonymous codon positions indicate that moderately strong selection is or was operating on these retroviral RT gene segments. The evolution of this class of endogenous retroelements is discussed.

Do patients with systemic sclerosis have abnormal gallbladder function?

OBJECTIVE: To determine gallbladder motility in patients with systemic sclerosis. DESIGN: Case control study. SETTING: University hospital, out-patient department of rheumatology. PATIENTS: Ten patients with systemic sclerosis according to the criteria of the American Rheumatism Association with documented involvement of the gastrointestinal tract and 10 healthy controls matched for age, sex and body mass index. INTERVENTION: Cephalic vagal cholinergic simulation by modified sham feeding and hormonal stimulation by infusion of cholecystokinin. MEASUREMENTS: Gallbladder volume obtained by ultrasonography and determination of plasma cholecystokinin concentrations. RESULTS: Fasting gallbladder volumes were not significantly different between patients with systemic sclerosis and controls (19.6 +/- 1.9 cm3 and 23.3 +/- 2.9 cm3, respectively, mean plus or minus standard error of the mean). Neither were there significant differences in reduction of gallbladder volume in response to modified sham feeding (35 +/- 4% and 33 +/- 4%, respectively) nor during cholecystokinin infusion (56 +/- 4% and 60 +/- 6%, respectively). The increase in plasma cholecystokinin levels during infusion was not different in the two groups. CONCLUSION: Gallbladder motility in patients with systemic sclerosis is preserved in response to both cholinergic and hormonal stimulation, even when other gastrointestinal motor disturbances are present. These results suggest that patients with systemic sclerosis are not at increased risk for cholelithiasis because of gallbladder dysmotility.

Effect of antrectomy and truncal vagotomy on erythromycin induced pancreatic polypeptide secretion.

Erythromycin, a motilin agonist, enhances gastrointestinal motility but also stimulates endogenous pancreatic polypeptide (PP) secretion. We investigated whether the effect of erythromycin on PP release is dependent on (1) prokinetic activity of erythromycin generated from the antrum and (2) the long vagus nerve since erythromycin acts via cholinergic neurons. Erythromycin induced PP secretion was determined in 14 patients with antrectomy (6 patients with Billroth I type anastomosis, 8 patients with Billroth II type anastomosis), in 6 patients with truncal vagotomy and pyloroplasty but without gastric resection and in 8 healthy controls. Plasma PP levels in response to erythromycin (3 mg/kg i.v.) were determined at regular intervals for 180 min. Erythromycin induced a significant increase in plasma PP in the control subjects from 22 +/- 4 pmol/l (basal) to 49 +/- 4 pmol/l at 10 min. In the patients with truncal vagotomy plasma PP secretion after erythromycin was significantly (P < 0.05) increased (peak increment vs. basal: 98 +/- 10 pmol/l vs. 27 +/- 2 pmol/l) and prolonged compared to controls. In the patients with antrectomy no significant increases in plasma PP over basal were observed after erythromycin infusion. It is concluded that erythromycin stimulates PP secretion in healthy controls. The PP response to erythromycin is exaggerated after truncal vagotomy but absent after antrectomy indicating that the antrum is essential for erythromycin induced PP secretion.

Application of the NASBA nucleic acid amplification method for the detection of human papillomavirus type 16 E6-E7 transcripts.

Using a human papillomavirus type 16 (HPV-16) E6-E7 specific primer set in a nucleic acid sequence-based amplification (NASBA) reaction, detection of HPV-16 transcripts was accomplished in a single enzymatic reaction at 41 degrees C. The NASBA reaction product was visualized either by Northern bolt analysis with an HPV-16 E6-E7-specific 32P-labelled oligonucleotide probe or by a non-radioactive enzyme-linked gel assay (ELGA). In combination with a rapid nucleic acid extraction procedure this method appears to be very suitable for the sensitive and specific detection of HPV-16 transcripts on small amounts of HPV-16-expressing cells of various sources, including cervical smears.

Effect of erythromycin on gallbladder emptying in patients with antrectomy or truncal vagotomy.

OBJECTIVES: Erythromycin, a motilin-like agent, stimulates gallbladder contraction in healthy control subjects. Because the action of erythromycin is cholinergic dependent and possibly related to premature phase III migrating motor complex activity in the antrum, we investigated the effect of erythromycin on gallbladder volume in six patients with truncal vagotomy without gastric resection and 14 patients with antrectomy (6 with Billroth I anastomosis, 8 with Billroth II anastomosis), and we compared the results obtained with those in eight healthy controls. In addition, the effect of meal ingestion on gallbladder volume was studied. METHODS: Gallbladder volumes, measured with ultrasonography, were determined every 15 min for 180 min after erythromycin infusion (3 mg/kg i.v.), as well as 30 and 60 min after meal ingestion. RESULTS: Basal gallbladder volumes were not significantly different among the four groups. Erythromycin induced a significant (p < 0.01-0.05) gallbladder contraction of maximal 46 +/- 6% in the controls, 49 +/- 9% in the patients with truncal vagotomy, and 38 +/- 7% in the patients with antrectomy and Billroth I anastomosis. In the patients with antrectomy and Billroth II anastomosis, no significant reduction in gallbladder volume after erythromycin was observed. Meal-induced gallbladder contraction was normal in all patients, including those with Billroth II anastomosis. CONCLUSIONS: These results indicate that neither the long vagus nerve nor the antrum is essential for erythromycin-induced effects on the gallbladder. Because no significant reduction in gallbladder volume in response to erythromycin was observed in the patients with antrectomy and Billroth II anastomosis, we suggest that duodenojejunal anatomical integrity is essential for erythromycin-induced gallbladder contraction.

Effects of somatostatin and loxiglumide on gallbladder motility.

Cholecystokinin (CCK) is the major hormonal stimulus of gallbladder contraction. Both somatostatin and CCK-A receptor antagonists inhibit stimulation of the gallbladder by CCK. The aim of this study was to compare the effect of somatostatin and the CCK-A receptor antagonist loxiglumide (CR 1505) on gallbladder volume at baseline and after feeding. In random order nine healthy subjects received somatostatin (IV loading dose 125 micrograms, followed by IV infusion of 125 micrograms.h-1), loxiglumide (10 mg.kg-1.h-1) and control saline. Gallbladder volumes and plasma CCK levels were measured basally and during stimulation by an intraduodenal infusion of fat using, respectively, ultrasound and a sensitive and specific radioimmunoassay. Mean basal gallbladder volume was similar prior to the saline control (28.5 ml), loxiglumide (28.7 ml) and somatostatin (23.4 ml) experiments. In the control experiment, intraduodenal fat led to a significant increase in plasma CCK from 2.6 to 4.8 pmol.1-1, accompanied by contraction of the gallbladder to 2.0 ml. Loxiglumide induced dilatation of the gallbladder to 40 ml and prevented the any contraction in response to intraduodenal fat. During the somatostatin infusion, gallbladder volume remained the same both basally and during fat stimulation. The plasma CCK response to intraduodenal fat was exaggerated by loxiglumide and was abolished by somatostatin.

Identification of a unique group of human papillomavirus type 16 sequence variants among clinical isolates from Barbados.

The naturally occurring sequence variation of human papillomavirus type 16 (HPV-16) was analysed by direct sequence analysis of the PCR products of the long control region (LCR), the E5 and E7 open reading frames (ORFs), a segment of the L2 ORF overlapping the early viral poly(A) signal and a small segment of the L1 ORF or clinical isolates from Barbados and The Netherlands. Despite the widely different geographical and ethnic origin of the two groups of specimens, sequence analysis revealed relatively few mutational differences. Analysis of the LCR and the E5 ORF appeared to be the minimum requirement for the correct positioning of these variants in the HPV-16 phylogenetic tree. Most of the Barbadian variants appeared to be located at a unique position in the HPV-16 phylogenetic tree, at the internal branch close to the point where the European and Asian branches diverge. In contrast, most of the Dutch samples were located on the European branch.

Nutrient-specific effects of modified sham feeding on pancreatic polypeptide release.

OBJECTIVE: To study the effect of meal composition on pancreatic polypeptide release during modified sham feeding. DESIGN: In random order and on separate occasions, isocaloric, isothermic, isoosmotic, homogenized meals (1050 kJ; 250 kcal) either rich in fat (walnuts; 64 g fat, 7 g protein, 15 g starch per 100 g), protein (codfish, 1 g fat, 23 g protein per 100 g) or carbohydrates (bananas; 22 g starch, 1 g protein per 100 g) were sham-fed for 30 min by tasting and spitting out the meal. The plasma pancreatic polypeptide response was monitored by radioimmunoassay at 10 min intervals from 20 min before to 120 min after modified sham feeding. SETTING: Department of Gastroenterology and Hepatology of a University Hospital. SUBJECTS: Seven healthy volunteers: 3 male, 4 female; age 45 (range 30-77) years. RESULTS: Integrated plasma pancreatic polypeptide responses to modified sham feeding of codfish (1088 +/- 395 pM*120 min; P < 0.05) and walnuts (1200 +/- 542 pM*120 min) were distinctly higher (P < 0.05) than to modified sham feeding of bananas (-390 +/- 291 pM*120 min). CONCLUSIONS: These results demonstrate that the pancreatic polypeptide response to modified sham feeding is dependent on the composition of the meal.

Gallbladder responses to modified sham feeding: effects of the composition of a meal.

Changes in gallbladder contraction and plasma cholecystokinin release were studied following modified sham feeding of 3 different isocaloric meals rich in either fat, protein or carbohydrates in healthy volunteers, and results were compared with those following real feeding of comparable meals. In contrast to carbohydrate-rich meals (8 +/- 19 ml/120 min), fat- (-412 +/- 46 ml/120 min) and protein-rich meals (-352 +/- 42 ml/120 min) reduced integrated gallbladder volume (P < 0.05) in response to modified sham feeding. Plasma cholecystokinin levels were not significantly influenced by modified sham feeding of fat, protein or carbohydrates. Real feeding of a carbohydrate-rich meal also failed to significantly reduce gallbladder volume and to stimulate cholecystokinin release (-45 +/- 40 ml/120 min and 51 +/- 11 pmol/120 min, respectively), while real feeding of both fat- and protein-rich meals distinctly reduced gallbladder volume (-679 +/- 76 and -564 +/- 53 ml/120 min, respectively; P < 0.05) and increased cholecystokinin release (651 +/- 72 and 504 +/- 43 pmol/120 min, respectively; P < 0.05). This study demonstrates that gallbladder contraction during the cephalic phase of meal stimulation is dependent on the fat, protein and carbohydrate percentages of a meal, and is activated by different mechanisms than the intestinal phase of a meal.

Effect of duodenal juice on bombesin-stimulated cholecystokinin release during loxiglumide administration in man.

Stimulation of cholecystokinin release by bombesin in augmented by cholecystokinin receptor blockade with loxiglumide. We hypothesize that this augmented cholecystokinin release results from inhibition of the pancreatico-biliary response to bombesin during cholecystokinin receptor blockade. To test this hypothesis, we infused bombesin for 180 min in six healthy subjects Three bombesin-infusion experiments were performed in each subject in random order on different days. In two of these experiments loxiglumide was co-infused with bombesin, while in the third experiment saline was co-infused with bombesin. In one of the loxiglumide experiments, duodenal juice, collected on the previous day during infusion of cholecystokinin-GIH, was reperfused intraduodenally during the second hour of bombesin infusion. In the saline experiment, the integrated cholecystokinin response during the first hour of bombesin-infusion (262 +/- 63 pmol 60 min-1) was significantly (P < 0.01) higher than during the second (88 +/- 26 pmol 60 min-1) and third (87 +/- 31 pmol 60 min-1) hour of bombesin-infusion. Loxiglumide augmented bombesin-stimulated cholecystokinin secretion from 262 +/- 63 pmol 60 min-1 to 453 +/- 63 pmol 60 min-1 in the first hour of bombesin infusion (P < 0.01). Integrated cholecystokinin values in the second (489 +/- 90 pmol 60 min-1) and third (450 +/- 74 pmol 60 min-1) hour of the loxiglumide experiment, were significantly (P < 0.01) higher than in the saline experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of acute hyperglycaemia on gall bladder contraction induced by cholecystokinin in humans.

This study examined the effect of acute hyperglycaemia, induced by intravenous glucose, on gall bladder motility. Six healthy volunteers were studied in random order on three occasions during normoglycaemia and hyperglycaemia with blood glucose concentrations stabilised at 8 and 15 mmol/l. Gall bladder volumes, measured with ultrasonography, were studied before and during infusion of stepwise increasing doses of cholecystokinin (CCK-33; 0.25, 0.5, and 1.0 IDU.kg-1.h-1). Each dose was given for 30 minutes. Pancreatic polypeptide (PP) secretion was determined as an indirect measure of cholinergic tone. Infusion of CCK-33 resulted in significant dose dependent reductions in gall bladder volume in all three experiments. Compared with normoglycaemia the gall bladder contraction was significantly (p < 0.05) reduced during infusion of 0.25 and 0.5 IDU kg-1.h-1 CCK-33 in the 8 mmol/l hyperglycaemic experiment, and during infusion of 0.25, 0.5, and 1.0 IDU kg-1.h-1 CCK-33 in the 15 mmol hyperglycaemic experiment. During hyperglycaemia basal plasma PP concentrations and PP secretion in response to CCK-33 were significantly (p < 0.05) reduced. It is concluded that blood glucose concentrations affect gall bladder motility, that an acute hyperglycaemia at 8 and 15 mmol/l reduces the gall bladder responsiveness to CCK-33 in a dose dependent manner, and that hyperglycaemia reduces basal and CCK-33 stimulated plasma PP concentrations, suggesting impaired cholinergic activity during hyperglycaemia.