Comparative impact of Roux-en-Y gastric bypass, sleeve gastrectomy or diet alone on beta-cell function in insulin-treated type 2 diabetes patients

Although bariatric surgery is an effective treatment for type 2 diabetes by inducing weight loss and augmenting gut hormone secretion, the immediate effect on beta-cell function itself remains to be elucidated in type 2 diabetes. Therefore, a prospective, randomized trial was performed in 30 patients with insulin-treated type 2 diabetes and a body mass index ≥ 35 kg/m2. Patients were randomly assigned (1:1:1) to Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) in combination with protein-sparing modified fast (PSMF), or to PSMF alone. Eu- and hyperglycemic clamps were performed before and 3 weeks after surgery and/or PSMF initiation. The primary outcome was the evolution of insulin sensitivity and beta-cell function after surgery, calculated using the composite measures of glucose disposal rate, insulin secretion rate, and disposition index (DI). Results revealed that markers of insulin sensitivity increased similarly in all arms (p = 0.43). A higher marker for maximal beta-cell function was observed when comparing SG to PSMF (p = 0.007). The DI showed a clear positive evolution after RYGB and SG, but not after PSMF alone. Altogether, these findings indicate that bariatric surgery results in an immediate beta-cell function recovery in insulin-treated type 2 diabetes.

Pharmacokinetics of Oral Rebaudioside A in Patients with Type 2 Diabetes Mellitus and Its Effects on Glucose Homeostasis: A Placebo-Controlled Crossover Trial

Background and Objectives

Rebaudioside A, a steviol glycoside, is deglycosylated by intestinal microflora prior to the absorption of steviol and conjugation to steviol glucuronide. While glucose-lowering properties are observed for rebaudioside A in mice, they have been attributed to the metabolites steviol and steviol glucuronide. We aimed to characterize the pharmacokinetic and pharmacodynamic properties of rebaudioside A and its metabolites in patients with early-onset type 2 diabetes mellitus (T2DM).

Methods

This randomized, placebo-controlled, open-label, two-way crossover trial was performed in subjects with T2DM on metformin or no therapy at the University Hospitals Leuven, Belgium. Following oral rebaudioside A (3 g), plasma concentrations of rebaudioside A, steviol and steviol glucuronide were determined. The effect on glucose homeostasis was examined by an oral glucose tolerance test (OGTT) performed 19 h following rebaudioside A administration, i.e. the presumed time of maximal steviol and steviol glucuronide concentrations. The primary pharmacodynamic endpoint was the difference in area under the blood glucose concentration–time curve during the first 2 h of the OGTT (AUC_{Glucose(0–2h)}) for rebaudioside A vs. placebo.

Results

In total, 30 subjects [63.5 (57.8–69.0) years of age, 86.7% male] completed the trial. Rebaudioside A was detected as early as 1 h after administration in nearly all subjects. As expected, steviol and steviol glucuronide reached their maximal concentrations at 19.5 h following rebaudioside A administration. Rebaudioside A did not lower the AUC_{Glucose(0–2h)} compared to placebo (− 0.7 (95% CI − 22.3; 20.9) h·mg/dL, P = 0.95). Insulin and C-peptide concentrations were also comparable between both conditions (P > 0.05).

Conclusion

Rebaudioside A is readily absorbed after oral administration and metabolized to steviol and steviol glucuronide. However, no effect on glucose nor insulin or C-peptide excursion was observed during the OGTT at the time of maximal metabolite concentrations. Thus, no antidiabetic properties of rebaudioside A could be observed in patients with T2DM after single oral use.

Clinical Trial Registration

Registered on ClinicalTrials.gov (NCT03510624).

Supplementary Information

The online version contains supplementary material available at 10.1007/s13318-022-00792-7.

Transluminal removal of a giant fibrovascular polyp of the esophagus

Giant fibrovascular polyps of the esophagus are rare benign tumors that originate at the hypopharynx or the upper third of the esophagus. Because of the indolent and benign nature they are mostly discovered when very large with symptoms like dysphagia or regurgitation of the polyp into the mouth which can cause asphyxia and dead. The removal of these polyps is obligatory. Although more than 100 cases of giant fibrovascular esophageal polyps have been described in literature so far, the approach for removal is not yet standard and needs a customized use of medical technology from different disciplines. We present the case of a 42 year old man in whom a giant polyp was removed transorally by a combination of instruments and materials from different disciplines (gastroenterological, surgical and laryngological).

Thin bones: Vitamin D and calcium handling after bariatric surgery

Bariatric surgery has proven to be a valuable treatment option for morbid obesity. However, these procedures can lead to impaired intestinal absorption of calcium and vitamin D, thereby challenging calcium homeostasis and possibly contributing to bone loss leading to an increased fracture risk. Besides calcium and vitamin D malabsorption, hormonal changes occurring after surgery can also be the source of observed bone loss. In this review, first, a case report will be discussed, highlighting the relevance of this topic. Afterwards, changes in bone density and fracture risk, after the two most performed types of bariatric surgery, Sleeve Gastrectomy (SG) and Roux-en-Y Gastric Bypass (RYGB) will be discussed. In addition, we discuss the putative underlying mechanisms leading to bone changes based on both preclinical and clinical observations. Nonetheless, it is clear further research is needed to further elucidate the exact mechanisms of bone loss following bariatric surgery and subsequently identify potential treatment options for bone preservation.

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Bariatric surgery induces bone loss and leads to increased fracture risk.

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Bone resorption increases after both SG and, more strongly, after RYGB.

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Malabsorption and adipose tissue-related hormones likely contribute to bone loss.

Introduction of human papillomavirus vaccination in Belgium, Luxembourg and the Netherlands

AIMS

To document progress with human papillomavirus (HPV) vaccine introduction in three closely related European countries, one with organized (the Netherlands) and two with opportunistic cervical cancer screening (Belgium and Luxembourg).

METHODS

Experts involved in cervical cancer screening and national immunization programs from the three countries were contacted to provide information on the decision-making process concerning the introduction of HPV vaccine. Sales statistics were obtained from Intercontinental Marketing Services.

RESULTS

Advisory boards in all three countries advised organized HPV vaccination of girls of 12 years with variable catch-up policies. In Belgium, the national health authority partially reimburses the HPV vaccine for girls of 12-15 years (recently extended until 18 years). In Luxembourg, 12-year-old girls are invited for free vaccination, but the HPV vaccine is also free of charge for female adolescents of 13-17 years. The number of vaccines reimbursed in Belgium in December 2007 to May 2008 corresponds with the amount required to fully vaccinate 29% of the female population aged 12-15 years. In Luxembourg, between March and November 2008, the immunization program delivered a quantity of HPV vaccines which theoretically covered 29% of females aged 12-17 years. In the Netherlands, nationwide HPV vaccination of girls of 12 years will start in September 2009. The sales of HPV vaccines (all ages combined) were by far the lowest in the Netherlands.

CONCLUSION

Up to the end of 2008, HPV vaccination efforts reached less than a third of the target population in Belgium and Luxembourg. If the latest trend continues, the current policy is expected to reach to most half of the target population. Well-planned introduction of vaccination combined with an organized screening program and active surveillance are crucial for the program to achieve and monitor its desired aims. Such surveillance should include linkage between vaccination, screening and cancer registries.

Introduction of human papillomavirus (HPV) vaccination in Belgium, 2007-2008

This paper documents the progress of human papillomavirus (HPV) vaccine introduction in Belgium. Information on vaccine use is based on sales statistics and reimbursement claims. From November 2007 to November 2008, the National Institute for Health and Disability Insurance reimbursed the HPV vaccine for girls aged between 12-15 years. In December 2008, the age limit was extended to include girls up to the age of 18. In November 2008, the total number of HPV vaccines sold exceeded 530,000 doses. The number of vaccines reimbursed in Belgium, for the period November 2007-November 2008, corresponds to the amount required to fully vaccinate 44% of all girls aged between 12-15 years. However, the trend was decreasing over the last 10 months. By the current reimbursement policy, we can expect that maximum half of the target population can be reached. In Flanders (one of the three Communities in Belgium), the intention is to start, from September 2010, with a free school-based HPV immunisation for girls in the first year of secondary school (12 years of age), complemented with vaccination by a physician of choice. This strategy ensures a higher HPV vaccine coverage which is expected to be as high as the current coverage in the hepatitis B vaccination programme (approximately 80%) offered to boys and girls in the same age group and under the same circumstances.

Introduction of human papillomavirus (HPV) vaccination in Belgium, 2007-2008

This paper documents the progress of human papillomavirus (HPV) vaccine introduction in Belgium. Information on vaccine use is based on sales statistics and reimbursement claims. From November 2007 to November 2008, the National Institute for Health and Disability Insurance reimbursed the HPV vaccine for girls aged between 12-15 years. In December 2008, the age limit was extended to include girls up to the age of 18. In November 2008, the total number of HPV vaccines sold exceeded 530,000 doses. The number of vaccines reimbursed in Belgium, for the period November 2007-November 2008, corresponds to the amount required to fully vaccinate 44% of all girls aged between 12-15 years. However, the trend was decreasing over the last 10 months. By the current reimbursement policy, we can expect that maximum half of the target population can be reached. In Flanders (one of the three Communities in Belgium), the intention is to start, from September 2010, with a free school-based HPV immunisation for girls in the first year of secondary school (12 years of age), complemented with vaccination by a physician of choice. This strategy ensures a higher HPV vaccine coverage which is expected to be as high as the current coverage in the hepatitis B vaccination programme (approximately 80%) offered to boys and girls in the same age group and under the same circumstances.

Perinatal mortality and other severe adverse pregnancy outcomes associated with treatment of cervical intraepithelial neoplasia: meta-analysis

OBJECTIVE

To assess the relative risk of perinatal mortality, severe preterm delivery, and low birth weight associated with previous treatment for precursors of cervical cancer.

DATA SOURCES

Medline and Embase citation tracking from January 1960 to December 2007. Selection criteria Eligible studies had data on severe pregnancy outcomes for women with and without previous treatment for cervical intraepithelial neoplasia. Considered outcomes were perinatal mortality, severe preterm delivery (<32/34 weeks), extreme preterm delivery (<28/30 weeks), and low birth weight (<2000 g, <1500 g, and <1000 g). Excisional and ablative treatment procedures were distinguished.

RESULTS

One prospective cohort and 19 retrospective studies were retrieved. Cold knife conisation was associated with a significantly increased risk of perinatal mortality (relative risk 2.87, 95% confidence interval 1.42 to 5.81) and a significantly higher risk of severe preterm delivery (2.78, 1.72 to 4.51), extreme preterm delivery (5.33, 1.63 to 17.40), and low birth weight of <2000 g (2.86, 1.37 to 5.97). Laser conisation, described in only one study, was also followed by a significantly increased chance of low birth weight of <2000 g and <1500 g. Large loop excision of the transformation zone and ablative treatment with cryotherapy or laser were not associated with a significantly increased risk of serious adverse pregnancy outcomes. Ablation by radical diathermy was associated with a significantly higher frequency of perinatal mortality, severe and extreme preterm delivery, and low birth weight below 2000 g or 1500 g.

CONCLUSIONS

In the treatment of cervical intraepithelial neoplasia, cold knife conisation and probably both laser conisation and radical diathermy are associated with an increased risk of subsequent perinatal mortality and other serious pregnancy outcomes, unlike laser ablation and cryotherapy. Large loop excision of the transformation zone cannot be considered as completely free of adverse outcomes.

Long-term results of a non-ramdomized prospective mono-centre study of 1000 laparoscopic totally extraperitoneal hernia repairs

BACKGROUND

Information concerning short-term results for laparoscopic extraperitoneal hernia repair is available, but long-term results remain poorly documented. The purpose of this non-randomized prospective study was to evaluate recurrence and chronic pain after hernia repair over a period longer than 10 years.

MATERIALS AND METHODS

From 1995 to 2004, all patients aged 30 years or more, manifesting with inguinal hernia, were included in our study. Patients aged 20 to 30 years presenting with bilateral hernia, recurrent hernia, or who were heavy workers were also included. Patients who had pelvic irradiation, strangulated hernia, prostatic cancer resection, or a contra-indication to general anaesthesia were excluded. Of 1096 hernia repairs performed, 248 patients were excluded and underwent open repair and 848 patients (77.4%) were included in our prospective study, which corresponded to 1000 laparoscopic hernia repairs.

RESULTS

The sex ratio (male : female) was 5:8, and the average age was 56 years. Seven hundred and fifty-three hernias (75.3%) were first repairs, 247 (24.7%) were recurrent hernias, and 161 were bilateral hernias. There were no mortalities. The conversion rate was 1.1%, and the global postoperative morbidity rate was 10.3%. Average follow-up was 39 months in 92.2% of the patients. Hernia recurrence rate was 1.5%. Chronic pain occurred in 2.9%. During this follow-up, 22 contra-lateral hernias appeared in those patients who initially had unilateral hernia repair (3.2%). All of these contra-lateral hernias could be successfully treated using a laparoscopic total extraperitoneal approach.

CONCLUSIONS

The long-term results of this study demonstrate that preperitoneal laparoscopic hernia repair is a safe technique with a very low recurrence rate and low prevalence of chronic pain.

Spontaneous rupture of the spleen in relation to a non-Hodgkin lymphoma

A 35-year-old man was admitted for surgery with complaints of left upper abdominal quadrant pain, tachycardia and hypotension with no history of trauma. A splenomegaly had just been diagnosed one week before, during, the work up for asthenia. An immediate CT scan revealed an intraperitoneal haemorrhage with splenic rupture. During emergency laparotomy, a splenic rupture was found and a splenectomy was performed. Histopathology of the spleen confirmed the diagnosis of a non-Hodgkin lymphoma.

In vitro interaction between ecteinascidin 743 (ET-743) and radiation, in relation to its cell cycle effects

Ecteinascidin 743 (ET-743) is a new marine-derived agent with promising activity against a number of solid tumours. In four human tumour cell lines, the interaction between ET-743 and radiation was investigated in relation to the effects of ET-743 on the cell cycle, in vitro. Cell survival was measured based on quantitative staining of cellular protein by sulforhodamine B. A 24 h treatment with ET-743 before radiation resulted in a moderate increase in radiosensitivity in three out of four cell lines. Dose enhancement factors > or =1.8 were observed for concentrations resulting in 52, 46 and 30% cell kill in ECV304, H292 and CAL-27, respectively, whereas in A549 no radiosensitisation was observed (no significant increase in radiosensitivity). According to the combination index analysis, synergism was observed only in ECV304 and CAL-27 cells. A 24 h incubation with ET-743 resulted in a concentration-dependent G2/M block, which might explain the moderate radiosensitising effects in ECV304 and H292. The lack of radiosensitisation in A549 might be due to the S phase delay preceding the G2/M block at the moment of radiation, which only occurred in this cell line. In conclusion, ET-743 has moderate cell line-dependent radiosensitising properties; however, only when cytotoxic concentrations of ET-743 are used. In one of the four cell lines tested, no radiosensitisation was observed.

Retroperitoneoscopic lumbar sympathectomy with balloon dissection: clinical experience

PURPOSE

To describe our technique and clinical experience of retroperitoneoscopic lumbar sympathectomy with balloon dissection.

PATIENTS AND METHODS

From 1995 to 1999, 23 procedures were performed.

RESULTS

No complications were noted. The median hospital stay was 4 days. Of the 23 attempts, 2 had to be converted to open technique. Histologic examination demonstrated interruption of the sympathetic chain in 22 of the 23 cases and absence of nervous tissue in 1.

CONCLUSIONS

Once the technique is mastered, it can be performed fast, and it offers patients the benefits of a minimally invasive approach without the inconsistent therapeutic results of chemical sympathectomy.

Recurrent gastrointestinal blood loss of obscure origin: report of an exceptional case

A 66-year old tailor was admitted because of venous insufficiency of the left lower leg. During the hospital course, recurrent severe gastrointestinal blood loss developed. A classical approach was extended by enteroscopy and radionuclide scanning, followed by exploratory laparatomy with removal of two intra-abdominal sewing needles and a jejunal leiomyoma. After surgery, bleeding did not recur. This case illustrates the difficult diagnostic work-up of obscure gastrointestinal bleeding. It also shows that intra-abdominal sewing needles may migrate in the intestinal tract and remain silent during many years, eventually causing gastrointestinal bleeding.

Effect of sublethal doses of cadmium, inorganic mercury and methylmercury on the cell morphology of an insect cell line (Aedes albopictus, C6/36)

The effect of CdCl2 (44 microM), HgCl2 (3.7 microM), and MeHgCl (2 microM) on the morphology of Aedes albopictus C6/36 cells was studied at the light microscopical level. Treatment times and metal concentrations were in the sublethal range as determined by a fluorometric dye exclusion test. The three metal species had profound effects on the cell morphology. MeHgCl treatment induced the development of a large number of short, actin-supported, tangled filopodia. Both CdCl2 and HgCl2 induced long extensions. Pretreatment with colchicine but not with cytochalasin B prevented formation of these extensions which suggests that they were supported by microtubules. This was confirmed by immunostaining for microtubules. The extensions were relatively stable towards colchicine post-treatment. To authors' knowledge, this effect has not yet been described for heavy metals. The similarity with 20-hydroxyecdysone-treated cells and the occurrence of cytoplasmic feet in insect cells is discussed.

Recent developments in lipid emulsions: relevance to intensive care

For years, intravenous lipid supply has been considered as a means of providing an efficient fuel to many tissues of the body and of preventing or correcting essential fatty acid deficiency. The potential for lipid emulsions to modulate cell function via their content of specific fatty acids and of liposoluble vitamins has not received much attention yet. Soybean [long-chain triglycerides (LCT)] emulsions provide a valuable source of energy, but they are excessively rich in omega-6 essential fatty acids (FAs). Their infusion is associated with an accumulation of linoleate and a reduction of long-chain (> or = C20) omega-6 and omega-3 fatty acids in cell membrane phospholipids, as well as with a depletion of antioxidant status, associated with a reduction of alpha-tocopherol in plasma lipoproteins. Infusions of the mixed medium-chain triglycerides (MCT)/LCT (50%:50%; wt:wt) largely bypass these disadvantages. In addition, plasma elimination of MCT/LCT is faster than that of LCT. Recent advances indicate a great potential for omega-3 FAs incorporated into membrane phospholipids to modulate cell response to various stimuli and to influence several intracellular metabolic processes. Furthermore, some of these FA directly influence the production and the action of important mediators, the eicosanoids. In practical terms, an increased intake of omega-3 FAs may reduce inflammatory and thrombotic responses while protecting tissue microperfusion and immune defenses. Such properties may find interesting applications in several types of intensive care unit patients, provided that omega-3 FA incorporation takes place promptly. We recently had the opportunity to study in vitro and in vivo the metabolism of emulsions made of a mixture of MCT, soybean LCT, and fish oil triglycerides. Plasma elimination of such preparations appeared to be very fast, and their infusion was not associated with a prolonged residence of emulsion particles. In addition, uptake of remnants enriched with omega-3 FAs and liposoluble vitamins was fairly fast and occurred in several types of cells, leading to an efficient incorporation of omega-3 FAs in cell membranes within a few hours. The understanding that remnant uptake plays a significant role in the delivery of components included in lipid emulsions opens new areas of investigation and is likely to find several conditions of applications for new types of preparations.

Acute pneumoperitoneum without peritonitis. A case report

An uncommon case of pneumoperitoneum without peritonitis, related to small bowel diverticulosis is presented. Pneumoperitoneum is usually a life-threatening incident, most frequently attributed to a perforated viscus and generally requiring emergency surgery. Non surgical pneumoperitoneum, however, is known to be caused by a variety of pathological and non pathological entities. Small bowel diverticulosis is an extremely rare cause of chronic pneumoperitoneum without peritonitis. In the presence of mechanical bowel obstruction, the latter kind of pneumoperitoneum can suddenly become impressively increased. A conservative attitude is generally advocated in the presence of such a benign pneumoperitoneum. However, laparoscopic exploration may be helpful for the diagnosis.

Genetic engineering in plants

Until now most research, and its funding, has been focused on animal and human health care as well as simple microbiological model systems such as Escherichia coli and yeast. Molecular plant studies have generally lagged behind, often simply adapting discoveries from the animal field to plants. Clearly, good health and the efficient tackling of diseases is crucial for the well-being of humans, and good remedies have a high economic value for the pharmaceutical industry. However, one should not forget that plants are an essential component of the large ecosystem that is our planet. They are not only the basic food producers but they are also necessary for a balanced atmosphere (oxygen production) and stable and viable climates. Especially in this period of demographic explosion and growing environmental deterioration, there is a need to rebuild our agricultural systems. Plants also have a wide variety of 'non-food' uses, for instance as energy sources, construction materials, or cosmetics. Last, but not least, they produce a lot of chemicals that can be used as pharmaceuticals. The growing awareness of the importance of plants has coincided with the development of plant molecular biology. Specific features make them ideally suited for gene engineering and genetic studies in general.

Manipulation of tissue fatty acid profile by intravenous lipids in dogs

This study was undertaken to determine the effects on the fatty acid (FA) composition of various dog tissues of 4 different lipid emulsions (a 100% long-chain triacylglycerol (LCT) derived from soya bean oil emulsion, a mixed 50% medium-chain triacylglycerol (MCT)/50% LCT emulsion as well as both these emulsions supplemented with 10% fish oil (FO) triacylglycerols), when daily infused over 15 days as a substantial component of total parenteral nutrition. Lipids represented 55% of the non-protein energy. Blood samples as well as biopsies from liver, muscle and adipose tissue were taken 15 days before, and again immediately after TPN. In addition, the spleen was also removed immediately after TPN. Tissue FA composition was analysed by gas liquid chromatography of each lipid component after separation by thin layer chromatography. No differences in either safety or tolerance were detected between the different TPN preparations. In particular, infusion over 2 weeks of fat emulsions containing 10% fish oil was tolerated as well as conventional LCT and MCT/LCT emulsions. Relative linoleate content of tissue triacylglycerol (TG) was markedly increased in animals that received the LCT emulsions (e.g. from 22.6 +/- 2.5% to 32.2 +/- 0.6% in the liver), this effect being markedly reduced with MCT/LCT preparations. n-3FA were slightly incorporated into liver TG (from 0.0 +/- 0.0% to 2.3 +/- 0.7% and 1.2 +/- 0.4% for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) respectively, with LCT + FO), but remained undetectable in extrahepatic tissue TG. Of interest, medium chain FA were found in tissue TG after infusion of the mixed MCT/LCT emulsions. As expected, changes of tissue phospholipid (PL) composition involved only long-chain FA. Infusion of soya bean oil emulsion was associated with an increased content of linoleate in liver PL (from 13.6 +/- 0.4% to 17.7 +/- 0.4%), but not in other tissues. MCT/LCT did not markedly affect PL/FA pattern in any tissue. Supplementation with fish oil was associated with an efficient incorporation of n-3FA into tissue PL, particularly in the liver (from 0.4 +/- 0.1% to 2.5 +/- 0.3% for EPA and from 3.9 +/- 0.8% to 9.1 +/- 0.4% for DHA, with the LCT + FO emulsion).

Gastric volvulus as a complication of a left superior lobectomy in a patient with pre-existing hiatal hernia

The case of a 75-year-old man with a history of hiatal hernia, who develops an acute gastric volvulus 17 days after a superior lobectomy of the left lung, is described. No similar cases were found in literature.

Inflorescence-specific genes from Arabidopsis thaliana encoding glycine-rich proteins

Genomic and cDNA clones for three inflorescence-specific genes from Arabidopsis thaliana were isolated and characterized. The genes are tandemly organized in the genome on a 10 kb fragment. The expression of these genes is coordinately regulated in a developmental and organ-specific pattern. They are expressed predominantly in anthers at the later stage of flower development. The primary structure of the encoded gene products exhibits comparable features consisting of a hydrophobic domain at the N-terminal region followed by repeated glycine-rich motifs. Little homology is observed either between the glycine-rich domain of the three genes or with previously described glycine-rich proteins from other plant species.

Use- and frequency-dependent blockade by UL-FS 49 of the if pacemaker current in sheep cardiac Purkinje fibres

The mechanism by which the bradycardiac agent UL-FS 49 blocks the if pacemaker current was investigated in sheep Purkinje fibres using the two microelectrode voltage-clamp technique. If was activated by 1 s pulses applied between -30 mV and -120 mV at 0.4 Hz in a modified Tyrode solution containing BaCl2 and MnCl2, and with TRIS replacing most of the Na+. UL-FS 49 caused an exponential decline of the if current amplitude during a train of pulses. Both the rate and extent of the if reduction increased with drug concentration, without there being a resting blockade. Recovery from blockade followed a single exponential time course during prolonged hyperpolarizations. The recovery rate was extremely slow and increased with more negative voltages, as did the extent of steady state recovery from blockade. A frequency-dependent reduction of the diastolic depolarization rate resulted from a use-dependent blockade of the pacemaker current.

[Efficacy of percutaneous caffeine in the treatment of apnea in the premature infant]

In 18 prematures (gestational age less than 32 weeks), an aqueous monohydrated caffeine colloidal gel was administered topically. High plasma levels were rapidly obtained with a loading dose divided in 4 applications by massaging, 1 ml of gel per kg body weight, at 12 hour intervals (18 mg caffeine base/kg). Maintenance was then instituted with a dose of 0.5 ml/kg/day. Treatment was initiated before 8 days of life, in children under assisted ventilation but without severe pulmonary involvement, during the period of weaning from the respirator. A good local and general tolerance was invariably observed and remarkable therapeutic efficacy was obtained.

Effect of acute suppression of acid secretion by omeprazole on postprandial gastrin release in conscious dogs

The effect of acute suppression of acid secretion induced by administration of a single dose of omeprazole (2 mg/kg body wt) on postprandial gastrin release was studied in 10 conscious dogs. In omeprazole-treated dogs, a sustained gastrin release was observed during a 10-h period after feeding, although greater than 95% of the meal had left the stomach after 4 h. This sustained gastrin release could be inhibited by acidification of the gastric lumen, by somatostatin, and by atropine. Insulin and bombesin induced considerable gastrin release in omeprazole-treated dogs, but plasma gastrin concentrations returned almost to basal values after 3 h. Omeprazole administered alone had no significant effect on basal gastrin levels. These data indicate that, in dogs, when acid secretion is suppressed by omeprazole a meal induces a sustained gastrin release lasting for up to 10 h. This gastrin release is probably related to the fact that food has been in contact with the gastric lumen, as neither vagal nor bombesin stimulation induced such a sustained activity of the G cells.

Effect of cimetidine, ranitidine and omeprazole on postprandial gastrin and somatostatin release in conscious dogs

During a first series of experiments, the gastrin responses to a meal were measured and compared to the responses seen after administration of cimetidine (2.5 mg/kg/h) or omeprazole (2 mg/kg). During a second series of experiments the effects of cimetidine (2.5 mg/kg/h), ranitidine (0.5 mg/kg/h) and omeprazole (2 mg/kg) on post-prandial gastrin and somatostatin release were determined in experiments during which the intragastric pH was maintained close to 6.4. During a third series of experiments, the effects of cimetidine (2.5 mg/kg/h) and omeprazole (2 mg/kg) on basal gastrin and somatostatin release were estimated. Postprandial gastrin release was increased by cimetidine and by omeprazole. When acidification of the gastric content was prevented by intragastric titration, postprandial gastrin release was increased by about 100%. No further increase was observed when the animals were concomitantly treated with cimetidine, ranitidine or omeprazole. Intragastric titration did not alter postprandial somatostatin release. Concomitant administration of H2 blockers decreased the somatostatin response to the meal, while concomitant administration of omeprazole did not alter this release. No significant changes were observed in basal gastrin or somatostatin levels after administration of cimetidine or omeprazole.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of vagotomy and atropine on plasma somatostatin response to a meal in conscious dogs

In 4 conscious dogs with gastric fistulas the somatostatin responses to a meal were measured and compared to the responses seen after i.v. infusion of atropine sulfate (20 and 50 micrograms.kg-1.h-1) or cimetidine (8 mg.kg-1.h-1). The experiments were repeated after truncal vagotomy. The somatostatin responses to bombesin (0.5 micrograms.kg-1.h-1) were also measured before and after vagotomy. Vagotomy decreased basal and postprandial somatostatin levels and reduced the somatostatin responses to feeding during the first 30-min period following the ingestion of the meal but not during subsequent periods. Bombesin-induced somatostatin release was increased after vagotomy. Atropine decreased the somatostatin responses to the meal before and after vagotomy. Cimetidine had no significant effect. These studies suggest that, in conscious dogs, somatostatin released into the circulation is partly under vagal control and that, as for gastrin release, vagal pathways for stimulation and inhibition are present. Our studies also suggest that cholinergic mechanisms are involved in the control of postprandial somatostatin release.

High meiotic stability of a foreign gene introduced into tobacco by Agrobacterium-mediated transformation

Two lines of transgenic Nicotiana tabacum transformed to kanamycin resistance by means of a binary Agrobacterium vector containing a nos-npt gene were investigated over three generations. Southern hybridization and crossing analyses revealed that a single copy of T-DNA had integrated in each line and that the kanamycin resistance was regularly transmitted to the progeny as a monogenic dominant trait. Homozygous transgenic plants were fully fertile, morphologically normal and did not significantly differ from wild-type plants in the quantitative characters examined (plant height, flowering time). The two lines showed very low, but significantly different levels of meiotic instability: kanamycin-sensitive plants occurred among backcross progeny from homozygous transgenic plants with frequencies of 6/45,000 and 25/45,000, respectively. The sensitive plants arose independently of each other and thus resulted from meiotic rather than mitotic events. These findings demonstrate for the first time that integrated foreign genes can be transmitted to progeny with the high degree of meiotic stability required for commercial varieties of crop plants. They emphasize the importance of non-homologous integration and of avoiding co-integration of inactive gene copies for achieving meiotically stable transformants.

A binary vector for transferring genomic libraries to plants

The transformation of mutant plants with a complete recombinant library derived from wild-type DNA followed by assay of transformed plants for complementation of the mutant phenotype is a promising method for the isolation of plant genes. The small genome of Arabidopsis thaliana is a good candidate for attempting this so-called shotgun transformation. We present the properties of an A. thaliana genomic library cloned in a binary vector, pC22. This vector, designed to introduce genomic libraries into plants, contains the oriV of the Ri plasmid pRiHR1 by which it replicates perfectly stably in Agrobacterium. Upon transfer of the library from E. coli to A. tumefaciens large differences in transfer efficiencies of individual recombinant clones were observed. There is a direct relation between transfer efficiency and stability of the recombinant clones both in E. coli and A. tumefaciens. The stability is independent of the insert size, but seems to be related to the nature of the insert DNA. The feasibility of shotgun transformation and problems of statistical sampling are discussed.