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Background The role of the gastric microbiome in development or persistence of equine glandular gastric disease (EGGD) remains to be investigated. Hypothesis/objectives The objective was to characterize the glandular mucosal and gastric fluid microbiomes of horses with and without EGGD. It was hypothesized that differences in the mucosal microbiome are associated with EGGD. Animals Twenty-four horses were enrolled. Methods Gastroscopy was performed and EGGD scores recorded (score 0, n = 6; score 1, n = 8; score ≥2, n = 10). Gastric fluid and pinch biopsies of healthy glandular mucosa and EGGD lesions were collected via gastroscope. 16S rRNA amplicon sequencing of the gastric fluid and glandular mucosal biopsies was performed. Relationships between gastric fluid and mucosal microbial community composition were evaluated among EGGD score groups (EGGD 0-BX, EGGD 1-BX, EGGD ≥2-BX) and among endoscopic appearances: controls from horses without EGGD and normal areas, hyperemic areas, and lesions from horses with EGGD. Results Microbial community structure of mucosal biopsies differed among EGGD score groups (Jaccard similarity index; P = .009). Principal coordinate analysis showed separate clusters for EGGD 0-BX and EGGD ≥2-BX. Conclusions and clinical importance A modest difference was detected in the community structure of the gastric glandular mucosal microbiome in association with EGGD score.

Background Wei Le San (WLS) is a Chinese herbal formula comprised of 9 herbs selected for their putative anti-inflammatory effects. Objectives To evaluate the effects of WLS administration in horses with nonglandular gastric ulcers. Animals Ten mixed breed mares (aged 7-21 years, 401-567 kg body weight). Methods Experimental design was a blinded, prospective, 2-period crossover study. All horses received a placebo (25 mL dextrose-based syrup; n = 10) and the treatment (WLS, 5 g in 25 mL dextrose-based syrup; n = 10), administered twice daily. Horses underwent a 1-week, alternating feed-deprivation period to induce or worsen existing ulcers; treatment began on day 7. Gastroscopic examination was performed on d0, d6, and d35, with gastric fluid pH obtained on d6 and d35. Gastric ulcer scores assigned by 3 masked observers were averaged for each examination. Results Ulcer number scores for horses treated with WLS (median = 0; range, 0-4) was not different from the untreated controls (median = 0.5; range, 0-4; P = .81) by the end of the treatment period. Ulcer severity score for treated horses (median = 0; range, 0-1) was also unchanged compared to the control group (median = 0.5; range, 0-1; P = .85). Gastric pH was not altered by either treatment, with a median of 2.1 (range, 1.9-4.1) for the horses treated with WLS and 2.8 (range, 1.6-7.2) in the untreated controls (P = .46). Conclusions and clinical importance The experimental model used to induce gastric ulceration was unable to discern a difference between the herbal supplement and the placebo in normal horses.

We assessed the impact of raising the upper section of the bed, and patient positioning, on ultrasound assessment of gastric fluid contents. We performed ultrasound examinations in 25 subjects lying on their back, left and right sides at bed angles of 0°, 30°, 45° and 90°; this was carried out while the subjects were fasted, and repeated 10 min after drinking ≥ 50 ml water. After drinking, gastric contents were detected more frequently in the 45° semirecumbent position compared with the supine and 30° positions. The diagnostic performance of the Perlas qualitative grading scale to detect gastric fluid volume > 1.5 ml.kg-1 was improved at 45°, compared with 0° and 30° angles. The use of a composite ultrasound grading scale at a 45° angle was associated with the best performance, with a sensitivity and specificity of 82%. Antral cross-sectional area was significantly increased when measured in the right lateral position, but there was no effect of raising the bed. In conclusion, raising the upper section of the bed significantly affected qualitative assessment of gastric fluid contents. Further studies are required to determine the most appropriate composite ultrasound grading scale and bed angle for fast and reliable qualitative ultrasound detection of fluid volumes > 1.5 ml.kg-1 .

The highly acidic gastric environment creates a physiological barrier for using therapeutic drugs in the stomach. While proton pump inhibitors have been widely used for blocking acid-producing enzymes, this approach can cause various adverse effects. Herein, we report on a new microdevice, consisting of magnesium-based micromotors that can autonomously and temporally neutralize gastric acid through efficient chemical propulsion in the gastric fluid by rapidly depleting the localized protons. Coating these micromotors with a cargo-containing pH-responsive polymer layer leads to autonomous release of the encapsulated payload upon gastric-acid neutralization by the motors. Testing in a mouse model, the in vivo results demonstrate that these motors can safely and rapidly neutralize gastric acid and simultaneously release payload without causing noticeable acute toxicity or affecting the stomach function, with the normal stomach pH restored within 24 h post motor administration.

Here the fabrication of a zinc (Zn) microrocket pill is reported, and its unique features toward active and enhanced oral delivery application are demonstrated. By loading Zn-based tubular microrockets into an orally administrable pill formulation, the resulting Zn microrocket pill can rapidly dissolve in the stomach, releasing numerous encapsulated Zn microrockets that are instantaneously activated and then propel in the gastric fluid. The released Zn microrockets display efficient propulsion without being affected by the presence of the inactive excipient materials of the pill. An in vivo retention study performed in mice clearly shows that the active pill dissolution and powerful acid-driven Zn microrocket propulsion greatly enhance the microrocket retention within the gastric tissue without causing toxic effects. By combining the active delivery feature of Zn microrockets with the oral administration of a pill, the Zn microrocket pill holds considerable potential for active oral delivery of various therapeutics for diverse medical applications.

Aim The aim of this study was to determine whether the concentration of cytokines in the gastric fluid at birth was associated with chorioamnionitis or funisitis and with the white blood cell counts of very premature newborns. Methods We retrieved gastric fluid from 27 preterm infants with a gestational age of

The aim of this study was to evaluate the influence of microbiological and technological factors on the viability and functionality of probiotic Lactobacillus strains. In particular, the influence of harvesting time, food matrix, refrigerated storage, time of inoculation and refrigerated storage in fermented milk on the resistance to simulated gastric digestion (RSGD) was evaluated. Moreover, strain resistance to simulated gastric digestion was compared to human gastric fluid. Results showed that the variables studied affected, in a different way and in a strain-dependent manner, the RSGD. No direct relation was observed between cell viability and RSGD.

Incorporation of drug-loaded nanoparticles (NPs) in colon-specific delivery systems shows potential for raising local drug concentrations, tumor targeting and improving chemotherapy. Alginate microcapsules (15-80 µm diameter) containing insoluble Eudragit(®) RS NPs as models were characterized precisely in terms of NP loading and release kinetics. High NP loading (22%, w/w of the dried microcapsules) combined with negligible release in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) suggested that high concentrations of NPs could be transported to the colon. However, NP aggregation was confirmed at extremely low concentration (0.0003%, w/v) in alginate solution (0.007%, w/v) and after release from alginate microcapsules. Indomethacin, a model anticolorectal cancer drug, was encapsulated in pH-responsive Eudragit(®) S100 NPs (116 nm, 5%, w/w drug loading) using the nanoprecipitation method. Approximately 90% of the drug load was released from the NPs in SGF and SIF before transfer to simulated colon fluid (SCF). However, incorporation of NPs in 2 mm alginate pellets resulted in a significantly higher fraction of the drug load (around 60%) being available for release in SCF. Delivery of isolated NPs to the colon for interaction with and uptake by cancer cells requires elimination of NP-excipient interactions that promote NP aggregation. NP-loaded alginate carriers, meanwhile, offer a promising strategy for delivery of anticancer drugs to tumor sites in the colon and reducing systemic side effects.

Background: Cross-sectional gastric antral area (GAA) measurements by ultrasonography (US) have been proposed for preoperative assessment of gastric volume in adults but not been validated in children. This study investigates whether in children gastric volumes can be predicted by US performed in different patient positions. Method: Gastric fluid and air volumes were examined by magnetic resonance imaging before or up to 120 min after ingestion of 7 ml·kg(-1) diluted raspberry syrup in healthy volunteers who had fasted overnight. GAA was measured with US three times each in supine (SUP), elevated 45° degree supine (E45) and right decubital (RDC) position using imaging planes defined by vascular landmarks. Correlation coefficients (Pearson) between GAA and gastric volumes were calculated and Bland-Altman analysis performed. Results: Sixteen children aged from 6.4 to 12.8 (9.2) years were included in 23 examinations: 6 after overnight fasting, 3 directly after, and 14 with a delay of 74 ± 35 min after fluid intake. GAA was 221 ± 116, 218 ± 112, and 347 ± 188 mm(2) for SUP, E45, and RDC position, respectively. The best correlation between body weight corrected total gastric/gastric fluid volume (TGV(w) /GFV(w) ) with GAA was found for RDC position (R = 0.79; P

Integrated low-temperature co-fired ceramic (LTCC) modules are widely used in commercial wireless data and cellular communication devices. Recently, a number of researchers have demonstrated the use of LTCC materials and assembly processes to build integrated microelectromechanical and microfluidic devices, incorporating a variety of electrical, optical, electromechanical, and fluidic functions. However, the long-term stability and biocompatibility of the LTCC materials for microfluidic and specifically biomedical devices have yet to be addressed. The biostability of LTCC materials has been examined in three different commercial LTCC materials using a bioleaching approach. The leaching rate has been obtained in several common biological fluids using weight loss and elemental analysis to quantify the leaching rate. Our results indicate significant dissolution of LTCC materials in simulated gastric fluid and highly basic solutions. However, only minimal leaching was demonstrated in both phosphate buffer saline and simulated body fluid solutions.

Summary A technique comprising constant infusion and aspiration via nasogastric tube was used to quantify basal gastric secretion in 9 healthy foals aged 4–7 months and weighing 156 to 215 kg. Gastric fluid was collected continuously for 3 h from an in situ double lumen nasogastric tube attached to a constant suction device (5–10 mmHg). Phenol red (50 mg/litre), an inert marker, was infused continuously (250 ml/h) during the same period to determine loss of gastric fluid through the pylorus. Samples were collected every 15 mins and aspirated volume (VASP), pH, phenol red recovery (PRR) and hydrogen ion concentration (AO) were measured. Gastric secretory volume (VS) and acid concentration (ACD) were calculated. The mean (sd) VASP was 6.54 (1.31) ml/kg bodyweight (bwt)/h; pH was 1.76 (0.25), PRR was 77.7% (11.7), and AO was 0.43 (0.18) mmol/kg bwt/h. Mean (sd) ACD and VS were 59.17 (18.88) mmol/litre and 7.07 (1.73) ml/kg bwt/h, respectively. The AO, ACD, and VS were corrected for PRR. This technique is an alternative to invasive procedures and may be useful for evaluating basal and stimulated gastric secretion in foals and horses.

In this study, the virulence heterogeneity of Listeria monocytogenes serotype 4b strains of different origins was analysed on different levels. On one hand, the survival of L. monocytogenes strains in synthetic gastric fluid was studied. On the other hand, the pathogenic potential of strains with different inlB expression levels was analysed in an A/J mouse model for gastrointestinal listeriosis. Differences in survival capacity in gastric fluid and in in vivo virulence potential were observed between the tested strains. No clear correlation between the origin and the obtained data could be made. However, these results confirm the existence of heterogeneity in virulence potential of L. monocytogenes serotype 4b strains.

We report a case where use of the size 2 1/2 ProSeal laryngeal mask airway helped to prevent pulmonary aspiration of regurgitated gastric fluid. We describe the management of this case and discuss the potential advantages of this modified laryngeal mask airway for supraglottic airway management in pediatric patients.

A calcium-induced pectin gel bead (PB) containing pectin hydrolysate and/or chitosan (CS) was prepared, after which the relationship between erosion of the PB and drug release from the PB in artificial gastrointestinal juice was investigated. The PB gradually disintegrated in gastric fluid, and the rate of erosion of the PB was changed by modification of the gel matrix. The amount of calcium ion used to make the PB had little effect on drug release; however, adding CS to the PB markedly suppressed drug release in intestinal fluid. © 2005 Wiley Periodicals, Inc. Adv Polym Techn 24:46–50, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20029

To investigate the relationship between duodenogastric reflux and ulceration, gastric fluid was collected from the 1st (n = 26) and 3rd (n = 45) gastric compartments of llamas and alpacas during postmortem examination. Gastric fluids were analyzed for the presence of bile acids. Additionally, the 3rd compartment was examined grossly for the presence of erosions or ulcers, and the intestines were examined for evidence of fluid distention. Detectable bile acids were found in the 3rd compartment fluid of 1 of 28 camelids without ulcers, 7 of 14 camelids with ulcers, and 3 of 3 camelids with intestinal distention. Third compartment bile content was significantly higher in camelids with ulcers (median = 2.9 micromol/L) or intestinal distention (median = 371.5 micromol/L) than those with neither (median = 0 micromol/L). Bile acids were detected in the 1st gastric compartment in only 2 camelids. These findings suggest a reflux of duodenal contents, including bile acids, into the 3rd compartment in camelids with ulcers, similar to what is seen in camelids with poor intestinal emptying. Whether bile reflux was the cause of the ulcers or occurred after or concurrent to their development remains unknown.

This study demonstrates the first example of completely food-based edible electrochemical sensors. The new edible composite electrodes consist of food materials and supplements serving as the edible conductor, corn, and olive oils as edible binders, vegetables as biocatalysts, and food-based packing sleeves. These edible composite electrodes are systematically characterized for their attractive electrochemical properties, such as potential window, capacitance, redox activity using various electrochemical techniques. The sensing performance of the edible carbon composite electrodes compares favorably with that of "traditional" carbon paste electrodes. Well defined voltammetric detection of catechol, uric acid, ascorbic acid, dopamine, and acetaminophen is demonstrated, including sensitive measurements in simulated saliva, gastric fluid, and intestinal fluid. Furthermore, successful biosensing applications are realized by incorporating a mushroom and horseradish vegetable tissues with edible carbon pastes for imparting biocatalytic activity toward the biosensing of phenolic and peroxide compounds. The attractive sensing performance of the new edible sensors indicates considerable promise for physiological monitoring applications and for developing edible and ingestible devices for diverse biomedical applications.

Summary Forty-three patients aged 3–6 years, undergoing minor surgery were studied. Parents staying with their children were asked to evaluate the anxiety of their children and themselves by a visual–analogue scale the night before surgery (VAS-N) and just before premedication in the morning (VAS-M). After induction, gastric fluid was collected and the volume and pH were measured. Patients with a VAS-M lower than 5 were considered the low-anxiety group ( L-group; n=24) and the remainder comprised the high-anxiety group (H-group; n=19). The gastric volume of the H-group was significantly lower than that of the L-group. No difference was found in pH. A significant overall correlation of VAS-N was found between patients and their parents. These results suggest that the low level anxiety of children and their parents could not reduce the volume and acidity of gastric fluid and consequently the risk of aspiration pneumonia.

Summary A prospective study of otherwise healthy unpremedicated children scheduled for outpatient surgery was undertaken to determine the relationship between preoperative anxiety and gastric fluid volume and acidity in children. The anxiety level of the child, using a six point anxiety scale, was determined in the preoperative holding area 15–30 min before surgery. After induction of anaesthesia and tracheal intubation, a multi-port large bore catheter was inserted orally to aspirate gastric contents. Gastric fluid volume was measured and its pH was determined by an Accumet® 915 pH meter. One hundred and fifty patients, between 2 and 10 years of age (mean 5.3 ± 3.0 yrs), weighing 11.2–69.0 kg (mean 22.3 ± 15.4) were studied. Gastric contents could only be aspirated in 101 out of 150 patients. Gastric fluid volume averaged 0.41 ± 0.31 ml·kg−1 in these 101 patients. The average pH was 1.54 ± 0.40. Thirty two patients (21%) had gastric fluid volume > 0.4 ml·kg−1 and pH

There is no definitive method to determine if a novel food protein will become an allergen. For this reason, the allergenic risk of a novel food protein is currently evaluated using a weight-of-evidence (WOE) approach. The components of this WOE approach were arrived at based on expert opinion rather than evidential science. Digestive stability is considered a physiochemical property of food allergens. For food allergens to interact with the immune system via the intestinal mucosa, they must survive the gastric digestion process in an immunoreactive state. An in-vitro assay based on simulated gastric fluid (SGF; 0.32% pepsin at pH 1.2) has been adapted for use with purified proteins to evaluate the stability of the primary structure of novel food proteins. SGF results are currently used as one component in a WOE approach for predicting the risk that a novel food protein will become an allergen. The SGF assay was adopted based an initial investigation that indicated several known allergens were more resistant to SGF compared with several non-allergens. Subsequent investigations have called this correlation into question. In addition, artifacts associated with interpretation of stability results using semi-quantitative approaches have been identified and more classical stability models have been used to enable quantitative comparisons among proteins; however, improved data interpretation has not supported a strong correlation between digestive stability in SGF and the allergenic status of food proteins. Potential interactions between proteins and food matrices have been identified as one factor that may contribute the poor predictive capability of this assay, as has the non-physiological conditions present in SGF. More physiological digestion models that include the food matrix have been suggested based on expert opinion, but as yet, no such assays have been shown to better discriminate food allergens from non-allergens compared with the SGF assay. More useful elements of the WOE approach include the source of the gene/protein, the prevalence of the protein in food, and the structural relationship with known allergens.

Summary Two hundred healthy, unpremedicated children, ages 1–10 years, scheduled for elective outpatient surgery were studied in order to examine the effect of minimizing preoperative fasting on perioperative blood glucose concentrations in paediatric patients. None of the patients ingested solids after midnight. On the day of surgery, the children were assigned to one of two groups. Group A children (n= 113) were not allowed any liquids for at least 6 h prior to surgery (NPO). Children in Group B (n= 87) ingested 10 ml·kg−1 of apple juice 2–4 h prior to the induction of anaesthesia. All patients received lactated Ringer's solution intraoperatively, unless BG at induction was 0.4 ml/kg. All patients in both groups had gastric pH < 2.5. This study shows that gastric fluid volume and pH following a 2–4 h fast are not different from the values measured in children who were subjected to a traditional fasting period of 6 h or longer. Moreover, apple juice consumed 2–4 h prior to surgery neither buffers gastric pH nor does it modify intraoperative glucose homeostasis in children.

The medical records of 75 horses with duodenitis-proximal jejunitis (DPJ) were reviewed. Ages, physical parameters, laboratory values, and treatment data were compared between horses surviving DPJ and horses not surviving DPJ (Table 1). Fifty of 75 horses (66.6%)survived. Sixty-six horses (88.0%)were managed with medical treatment alone and nine horses (12.0%) were managed with medical treatment plus surgical intervention. Using a logistic regression model, the association of each of the 19 physical and laboratory parameters with death was evaluated retrospectively in the 75 horses. Three parameters (anion gap, abdominal fluid total protein concentration, and volume of gastric fluid for the first 24 hours of hospitalization) were significantly associated with death by univariate analysis. Using a stepwise multiple logistic regression, two parameters remained significantly associated with death (P> 0.05), anion gap and abdominal fluid total protein concentration. (Journal of Veterinary Internal Medicine 1992; 6:307–311)

The standard of care for chronic gastro‐esophageal reflux disease (GERD), which affects up to 40% of the population, is the use of drugs such as proton pump inhibitors (PPIs) that block the production of stomach acid. Despite widespread use, the effects of PPIs on gastric fluid remain poorly characterized. In this study, gastric fluid was collected from patients undergoing cardiac surgery who were not (n = 40) or were (n = 25) actively taking PPIs. Various enzymatic and immunoassays as well as mass spectrometry were utilized to analyze the concentrations of bile, gastricsin, trypsin, and pepsin in the gastric fluid. Proteomic analyses by mass spectrometry suggested that degradation of trypsin at low pH might account, at least in part, for the observation that patients taking PPIs have a greater likelihood of having high concentrations of trypsin in their gastric fluid. In general, the concentrations of all analytes evaluated varied over several orders of magnitude, covering a minimum of a 2000‐fold range (gastricsin) and a maximum of a 1 × 106 –fold range (trypsin). Furthermore, the concentrations of various analytes were poorly correlated with one another in the samples. For example, trypsin and bile concentrations showed a significant (P < 0.0001) but not strong correlation (r = 0.54). Finally, direct assessment of bacterial concentrations by flow cytometry revealed that PPIs did not cause a profound increase in microbial load in the gastric fluid. These results further delineate the profound effects that PPI usage has on the physiology of the stomach., Further delineating the profound effects that PPI usage has on the physiology of the stomach, gastric fluid was collected from patients undergoing cardiac surgery who were not (n = 40) or were (n = 25) actively taking PPIs. Proteomic analyses by mass spectrometry suggested that degradation of trypsin at low pH might account, at least in part, for the observation that patients taking PPIs have a greater likelihood of having high concentrations of trypsin in their gastric fluid. Direct assessment of bacterial concentrations by flow cytometry revealed that PPIs did not cause a profound increase in microbial load in the gastric fluid, contrary with results previously obtained using culture‐dependent methods.

The aim of the study was to determine whether a single oral dose of omeprazole 40 mg is effective in increasing the pH of gastric residue above 2.5 at the time of anaesthetic induction in adult patients scheduled for elective gynaecological surgery. The patients were allocated to receive either chlorazepate dipotassium 25 mg alone or omeprazole 40 mg and chlorazepate dipotassium 25 mg on the night before surgery. Gastric volume and pH were measured after induction of anaesthesia. Patients who received omeprazole had a higher mean pH than control patients (p less than 0.001). The pH was less than 3.5 in 50% of patients in the control group, but in only 4.5% of those who received omeprazole (p less than 0.01). Mean (SEM) volume of gastric fluid was 15.2 (2.7) ml in the control group and 9.2 (1.8) ml in the omeprazole group, but the results were not statistically significant. A single dose of 40 mg omeprazole significantly decreased the number of patients at risk of aspiration pneumonitis.

The risk of arsenic exposure to deer mice (Peromyscus maniculatus) living in areas of naturally and anthropogenically elevated arsenic levels was determined using three separate calculations of arsenic daily intake: Estimated daily intake (EDI), bioaccessible EDI (BEDI), and actual daily intake (ADI). The present work is of particular interest, because the risk assessments were determined for animals naturally exposed to arsenic. Gastric fluid extraction was used to obtain bioaccessibility data for soil and plant samples collected from three study sites (background, mine forest, and tailings) in Yellowknife (NT, Canada). Calculations using the EDI indicated that deer mice living in tailings habitat (average soil arsenic concentration, 1,740 +/- 2,240 microg/g) should have been experiencing serious health effects as a result of their exposure to arsenic. Using BEDI and ADI in the risk assessment calculation, however, resulted in an order-of-magnitude decrease in calculated risk. In addition, results calculated using the BEDI and ADI were not significantly different, suggesting that using bioaccessibility provides a more realistic estimate of potential risk. The present results provide evidence that the use of EDI in traditional risk assessments may seriously overestimate the actual risk, which in some instances may result in expensive and unnecessary clean-up measures.

The role and importance of enterogastric secretion in the disposition and elimination of the weak base, meperidine (pKa 8.63), was studied after intravenous administration (50 mg) of the drug to 6 normal volunteers. Continuous collection of the gastric fluid over a 4-hr period demonstrated the establishment of high gastric fluid/plasma concentration ratios for meperidine (mean about 50, range, 10 to 200). However, the total amount of drug recovered, even after correction for incomplete collection, was only a small percentage of the administered dose. Under basal conditions a mean +/- SE of 1.9 +/- 0.3 mg, equivalent to 3.7% of the administered dose, was found in the total gastric aspirate. Stimulation of gastric secretion by subcutaneous injection of betazole (1.5 mg/kg) increased this recovery to 3.6 +/- 0.3 mg (7.2%) primarily due to the increase in gastric volumen output. Aspiration of the gastric fluid in either the basal or stimulated situation had no observable effect upon the plasma concentration/time profile of meperidine whether assessed by the terminal half-life, t 1/2 beta, or the plasma clearance; control values were 3.8 +/- hr and 1,190 +/- 130 ml/min, respectively. In 2 subjects "bile fluid" was also collected for 2.5 hr and found to contain less than 0.2% of the administered dose. Enterosystemic recycling is therefore of minor importance in the disposition and elimination of meperidine in man.

The results of preoperative examination, surgical intervention and the outcome of 50 cases of acute abdominal crisis in the horse are presented. Pre-surgical parameters discussed in this correlative study include duration of the condition prior to sergery, pulse rate, packed cell volume (PCV), abdominal distention, intestinal motility and tympany, rectal findings, reflux of fluid after passage of a nasogastric tube, and abdominal paracentesis. A retrospective study was performed to evaluate the usefulness of each clinical parameter in deciding that a case was surgical, arriving at a specific pre-surgical diagnosis, and in giving a prognosis. Rectal examination was the single most useful diagnostic tool. Reflux of gastric fluid through the nasogastric tube usually indicated obstruction of the small intestine.

Changes in PaO2 and PaCO2 during the induction of anaesthesia with thiopental, suxamethonium, and intubation were investigated in 20 patients who received preoxygenation for 2 min, but no ventilation before intubation. Both in fit patients below the age of 60 years (Group I) and in patients above that age - several suffering from cardiopulmonary disease - (Group II), PaO2 increased to about 40 kPa during preoxygenation and remained at that level during apnoea. Mean PaCO2 increased to 6.3 and 5.7 kPa in Groups I and II, respectively. No complications were seen, and it is concluded that the apnoea involved in the “crash induction” technique is safe. Pulmonary aspiration of acid gastric fluid may also occur in fasting patients, and it is suggrhted that even in elective cases ventilation might advantageously be replaced by preoxygenation when anaesthesia is induced with thiopental and suxamethonium.

Summary A clinical trial was conducted in which patients undergoing elective Caesarean section received either oral cimetidine 400 mg or magnesium trisilicate mixture BPC 20 ml before anaesthesia. The pH values of gastric fluid were significantly higher and the incidence of pH less than 2·5 was significantly lower in patients who received magnesium trisilicate mixture BPC. No adverse effects were observed in newborn infants whose mothers had received cimetidine and there was no significant difference in pH values of gastric fluid from the newborn in the two groups. The findings suggest that as a means of prophylaxis for Mendelson's syndrome in patients undergoing elective Caesarean section, magnesium trisilicate mixture BPC 20 ml is more effective than a single oral dose of cimetidine 400 mg, administered in the manner described.

The structure and function of the stomachs of nine bivalves are examined. These animals belong to the Gastrotetartika, Gastrotriteia, and Gastropempta, the three orders of the Polysyringia, a new sub-class of the Bivalvia suggested by Purchon (1960a). It is found that in all three orders there are common ciliary tracts and grooves. For example, tracts are always found in association with the duct openings, and a distinction between the right duct tract and the posterior sorting area is drawn. Another tract which is a constant feature of these stomachs, but which has not been noted before, is the antero-dorsal tract. A generalized polysyringian stomach is constructed. All the stomachs examined function similarly, there being set up in the lumina circulating currents of the gastric fluid. In general, large particles and masses of particles are recirculated until they are broken down, and small heavy particles are rejected by the sorting areas, of which three main types are described. Light particles in suspension in the stomach fluid are carried by the circulating current to the vicinity of the opening of the ducts of the digestive diverticula. The form of the primitive polysyringian stomach and the evolution of sorting areas are postulated. Possible steps in the evolution of the gastropemptan stomach through the gastrotetartikan form are suggested. The function of the appendix is that of a temporary store for large, heavy particles which escape the pallial sortingjnechanisms. It is noted that this organ occurs in all three orders of the Polysyringia.

In a clinical study including 40 patients, who all underwent elective gynaecological surgery, the quantity and acidity of the gastric contents were compared for patients premedicated with diazepam (Apozepam®) intramuscularly and orally, respectively. A significant difference was found with regard to both the quantity and acidity of the gastric fluid. The volume of gastric fluid was smaller after oral than after intramuscular premedication with diazepam (1.5 ml and 20 ml, respectively). The acidity of the gastric fluid was also less after oral than after intramuscular premedication (pH 2.4 and 1.8, respectively).