Cocarcinogenic action of aspirin on gastric tumors induced by N-nitroso-N-methylnitroguanidine in rats

Albino rats (noninbred) were divided into 4 groups: 1) 56 control rats, 2) 40 rats fed 1 ml aspirin suspension (40 mg/ml) twice a week, 3) 20 rats given N-nitroso-N-methylnitroguanidine (MNNG) solution (250 micrograms/ml) to drink ad libitum, and 4) 40 rats given both aspirin and MNNG. In 18 months, there were no gastrointestinal tumors in groups 1 and 2, 8 cases of gastric tumors in group 3, and 37 cases of gastric tumors in group 4. Adenocarcinomas of the glandular stomach were found in 21 of 40 rats in group 4 but in only 4 of the 20 rats in group 3; the difference in incidence was significant. Histologic and electron microscopic examination of the epidermoid carcinomas and adenocarcinomas in group 4 showed no difference from such tumors induced by MNNG only. Hyperplasia of the forestomach mucosa and hyperplasia of the pyloric gland region of the glandular stomach in group 4 were more severe.

Effect of 1-phenylpentanol on release of secretin and exocrine pancreatic secretion in dogs and humans

1-Phenyl-1-hydroxy-N-pentane is a synthetic derivative of an ingredient of Curcuma longa that is used as a condiment and dye. The effects of 1-phenyl-1- hydroxy-N-pentane on release of secretin, gastrin, and pancreatic secretion of bicarbonate and protein were studied in both dogs and humans. In fasting dogs with gastric fistulas and modified Herrera's pancreatic fistulas, intraduodenal administration of 1-phenyl-1-hydroxy-N-pentane (pH 6.7) in three different doses (25, 50, and 100 mg/kg) resulted in significant increases in both plasma secretin concentration and bicarbonate output. The increases in the two variables were dose related. The bicarbonate output and plasma secretin concentration produced by the doses of 1-phenyl-1-hydroxy-N-pentane correlated well. No significant change occurred in either protein output or plasma gastrin concentration. The effect of intragastric 1-phenyl-1-hydroxy-N-pentane on release of secretin and pancreatic secretion was also studied in the digestive state. While gastric pH was maintained at 5.5 by intragastric titration with 1 N NaOH after intragastric administration of 5% liver extract solution, intragastric administration of 1-phenyl-1-hydroxy-N-pentane (100 mg/kg) resulted in significant increases in both plasma secretin concentrations and pancreatic bicarbonate output. In the same experiment, the plasma gastrin concentration did not change significantly, whereas gastric acid secretion decreased significantly after the 1-phenyl-1-hydroxy-N-pentane administration. In 6 human volunteers, both plasma secretin concentration and pancreatic bicarbonate output significantly increased when 2% 1-phenyl-1-hydroxy-N-pentane solution, 30 ml/30 min, was infused in the upper jejunum. Again, no increase in the protein output was apparent. These studies indicate that endogenous secretin is released by an agent other than acid and suggest strongly that the increased pancreatic bicarbonate secretion is attributed to the increased plasma concentration of secretin. 1-Phenyl-1-hydroxy-N-pentane may be a useful agent for release of secretin in subjects with achlorhydria, severe hyposecretory state, or total gastrectomy.

Cholinergic role on release and action of motilin

In conscious dogs with gastric fistula and platinum electrodes on the antrum, duodenum and jejunum, IV atropine 100 micrograms/kg/hr and hexamethonium 10 mg/kg/hr, blocked cyclic increases in fasting plasma motilin concentration (PMC) and spontaneous migrating myoelectric complexes (MMCs) of both antrum and duodenum. The two drugs also blocked occurrence of premature MMCs produced by synthetic porcine motilin. In anesthetized dogs, electrical stimulation of cervical vagi with stimulation parameters: 9 V, 10 c/s, 5 msec, caused a significant increase in both portal and femoral venous PMC which was blocked by atropine. Fractionations of vagus nerve extracts by gel filtration using Sephadex G-50 superfine column revealed most of motilin-like immunoreactivity (MLI) with the same mobility as pure porcine motilin. Studies suggest that cholinergic influence plays a significant role on release of motilin.

One-stage reconstruction of the hypopharynx using myomucosal tongue flap and dermal graft

Reconstruction of the hypopharynx following total laryngectomy and total pharyngectomy provides a one-stage procedure to reconstitute the food conduit. A myomucosal advancement tongue flap forms the anterolateral walls, and the dermal graft forms the posterior wall of the reconstruction. Sixteen patients underwent reconstruction by this method. Thirteen required total laryngectomy and total pharyngectomy for extensive carcinomas. Two other patients who had previous laryngectomy and hypopharyngeal recurrence had pharyngectomy and repair by tongue flap and dermal graft. A third patient required laryngopharyngectomy following recurrence after supraglottic laryngectomy. No postoperative deaths have occurred. Anteriolateral defects of up to 8 cm in size can be reconstructed providing the neck can be flexed. Larger posterior defects superior to the eustachian tube can be closed. In two patients minor fistulas developed which closed spontaneously. One other patient had a delayed wound dehiscence and infection with fistula and carotid blowout. The patient had undergone previous surgery and radiotherapy. Deglutition was good to excellent in most patients. Three patients required esophageal dilatation with resolution. Cinegraphic studies have demonstrated the tongue to propel a bolus and to modulate speech which shows this repair to create a dynamic conduit. One patient had difficulty in swallowing because the left hypoglossal nerve was resected. Seven patients were alive with no evidence of disease 2 to 30 months postoperatively. Four patients who were free of their original disease died from other causes. Four patients died from original disease 5 to 23 months postoperatively. At present, one patient is alive with disease. Tongue flap and dermal graft provide a reliable and one-stage reconstruction following laryngopharyngectomy and should be considered as an alternative to distant flap and intestinal interposition reconstructive procedures.

Alpha-thalassemia in two Mediterranean populations

We used restriction endonuclease analysis to determine the incidence of alpha-thalassemia in two Mediterranean islands. In a random population sample, the gene frequency of deletion-type alpha-thalassemia-2 (-alpha) was 0.18 in Sardinians and 0.07 in Greek Cypriots. All cases were the rightward crossover type. From these frequencies and the known incidence of hemoglobin-H disease in these populations, we calculated the frequency of the alpha-thalassemia-1 genotype (--) and determined that it was low. We also found that beta-thalassemia homozygotes in sardinia have a higher incidence of alpha-thalassemia than normals and beta thalassemia heterozygotes because a significantly greater number of these homozygotes are also homozygous for the alpha-thalassemia-2 lesion. These findings support the theory that coinheritance of alpha-thalassemia mitigates the severity of beta-thalassemia and suggest that the protection is most pronounced when two alpha-globin genes are deleted.

A comparative study of argon and krypton laser. Photocoagulation in the treatment of presumed ocular histoplasmosis syndrome

Ninety eyes from 88 patients with active macular subretinal neovascular membranes of presumed ocular histoplasmosis were treated with photocoagulation: 45 eyes with blue-green argon laser and 45 with red krypton laser. Final visual results are compared between these two series and natural course of the disease. The krypton laser photocoagulated eyes obtained better final visual results when compared with both the argon laser treated series and natural course.

Solid-phase synthesis and biological activities of gastrointestinal hormones: secretin and motilin

Many successful solid-phase syntheses of peptide chains in the region of 20-40 amino acid residues have now been routinely reported. Utilizing standard solid-phase synthetic methodologies but, particularly, new and powerful purification techniques we have been developing rapid and efficient preparative routes for the numerous neuro-gastrointestinal peptides. In the present study, secretin and motilin were obtained in 16% and 10% yields, respectively, after simplified two-step purification of hydrogen fluoride-cleaved peptides by gel filtration followed by preparation high performance liquid chromatography. Peptides were essentially homogeneous by TLC and analytical high performance liquid chromatography. Secretin was found to have full biological activity when tested against a standard sample of natural material for effects on pancreatic secretion in the dog. Motilin exhibited full biological activity on interdigestive motility in the dog. Secretin has been reported to undergo rearrangement with loss of bioactivity during purification and prolonged storage. We observed no obvious problems during our abbreviated purification schedule and have found no loss of purity of peptide which has been kept for 6 months as power lyophilized from dilute acetic acid.

Gastric and small intestinal myoelectric dysrhythmia associated with chronic intractable nausea and vomiting

We describe a patient with symptoms of severe nausea, vomiting, epigastric bloating and pain, and marked weight loss due to a gastrointestinal motility disturbance. Motility abnormalities were characterized by uncoordinated high pressure (as high as 300 mm Hg) contractions and uncoordinated interdigestive motor complexes in the duodenum and small intestine, and tachygastria often associated with tachyarrhythmia in the gastric myoelectric activity recordings. Uncoordinated interdigestive myoelectric complexes again were found in the duodenum and small intestine. These abnormal myoelectric activities observed in the in-vivo study were confirmed in the in-vitro study. After distal hemigastrectomy and gastrojejunostomy, the symptoms of nausea, vomiting, and epigastric pain decreased considerably. Thus, the motility abnormality found in the study appears to be responsible for the symptoms described. This is probably a new clinical entity. The importance of manometric and myoelectric study of a gastrointestinal motility for unexplained nausea and vomiting is emphasized.

beta zero thalassemia in Sardinia is caused by a nonsense mutation

We report the characterization of a molecular lesion of beta thalassemia in Sardinia. Beta thalassemia in this area is predominantly the beta zero type with low levels of beta-globin mRNA. Translation assay of this messenger RNA in a cell-free system showed beta-globin chain synthesis only with the addition of an amber (UAG) suppressor transfer RNA. Double-stranded complementary DNA prepared from reticulocyte mRNA from a Sardinian patient was cloned in a bacterial plasmid and a beta-globin complementary DNA containing clone was isolated and sequenced. At the position corresponding to amino acid number 39, a single nucleotide mutation converted a glutamine codon (CAG) to an amber termination codon (UAG). We previously reported an amber nonsense mutation at amino acid 17 as a cause of Chinese beta zero thalassemia. Thus, beta zero thalassemia in Sardinia represents the second example of a nonsense mutation, and we predict that other beta zero thalassemias with mutations at various points along the beta-globin chain will be found to form a discrete subgroup of beta zero thalassemia. These experiments further illustrate the heterogeneity of lesions that lead to defective globin chain synthesis in beta thalassemia.

Effect of sodium oleate on plasma secretin concentration and pancreatic secretion in dog

The effects of sodium oleate and triglyceride infused into the duodenum of dogs with chronic pancreatic fistulas on pancreatic secretion and plasma immunoreactive secretin were investigated. The responses were compared with those following intravenous secretin infusions. Oleate markedly increased pancreatic water and bicarbonate secretion in a dose-related fashion, and these increases were accompanied by a small, but significant rise in the level of circulating immunoreactive secretin. No change in pancreatic secretion or in plasma secretin level was observed by the administration of triglyceride. Comparison of the bicarbonate response after oleate infusion with that after secretin administration suggests that the pancreatic stimulatory effect of intraduodenal sodium oleate is mediated to a major extent by the release of endogenous secretin.

Role of secretin on postprandial gastrin release in the dog: a further study

To determine the physiologic role of secretin on gastric secretory function, the effects of secretin in a physiologic dose on gastrin release and gastric acid secretion were studied in four dogs with vagally innervated fundic pouches. Three sets of experiments were performed in each dog: (1) meal alone, (2) meal after intravenous cimetidine to suppress acid secretion and release of secretin, and (3) meal after intravenous cimetidine with simultaneous intravenous secretin, 0.03 clinical unit (CU)/kg-hr. A significant increase in plasma secretin concentration occurred after ingestion of a meal. The postprandial increase in the secretin level was abolished by intravenous cimetidine 200 mg, whereas intravenous cimetidine resulted in a marked increase in the postprandial plasma gastrin concentration which was significantly greater than that after a meal alone. A plasma secretin level comparable to that of the postprandial period could be achieved in the same fasting dogs by intravenous secretin, 0.03 U/kg-hr in 2% dog albumin solution. The postprandial plasma gastrin concentration and acid secretion following intravenous cimetidine were significantly decreased by simultaneous intravenous secretin at a dose of 0.03 U/kg-hr. The observations indicate that secretin plays a significant role in the regulation of release of gastrin and gastric secretion of acid in the postprandial state in dogs.

Secretin is an enterogastrone in the dog

To determine the physiological significance of secretin on gastric secretion, effects of normal rabbit serum (control) and rabbit antisecretin serum (anti-S) on meat meal-stimulated gastric secretion of acid and pepsin from vagally innervated fundic pouches were studied in four dogs with gastric fistulas. The intravenous administration of control serum did not affect the postprandial rise in plasma secretin concentration, whereas intravenous anti-S virtually eliminated the circulating plasma secretin. Both plasma gastrin concentration and acid output following intravenous anti-S were significantly greater than those following intravenous control serum. However, pepsin outputs in the two groups of experiments were not significantly different. In the same dogs in the fasting state, during intravenous infusion of secretin in doses of 0.06 and 0.125 U . kg-1 . h-1, the acid output stimulated by intravenous human synthetic gastrin in a dose of 0.25 micrograms . kg-1 . h-1 was significantly less than that during intravenous saline. The studies indicate that secretin in a physiological dose can inhibit postprandial release of gastrin and gastric secretion of acid, and thus secretin is an enterogastrone in the dog.

[Antenatal diagnosis of sickle-cell anaemia by DNA analysis of amniotic fluid cells. A preliminary study in the French West-Indies (author's transl)]

The genetic polymorphism previously reported to be associated with the sickle-cell (beta S) gene in black U.S.A. citizens was studied in the population of two French West-Indies islands in order to evaluate its potential application to the antenatal diagnosis of sickle-cell anaemia. The polymorphism consists of a change in the DNA sequences located near the 3' end of the beta globin gene. The change can be detected by means of the restriction endonuclease Hpa I. When cellular DNA is digested with this enzyme, the beta globin gene is contained in a DNA fragment measuring either 7.6 or 13.0 kilobases (kb). In 70% of SS homozygous subjects in Martinique and 57% in Guadeloupe the beta S gene was carried by a 13.0 kb DNA fragment, whereas the normal beta A gene was carried by a 7.6 kb DNA fragment. This polymorphism would make it possible to detect the foetal beta S gene in the DNA of amniotic fluid cells by linkage analysis.

The release of biologically active secretin-like immunoreactivity into duodenal lumen of dogs

1. Immunoreactive secretin in the duodenal contents was determined in four conscious and four anaesthetized dogs in which hydrochloric acid (0.1 N) was infused into the duodenum at 2.2 ml./min. In the conscious dogs, immunoreactive secretin concentration in duodenal juice increased from 5-7 to 40-60 ng/ml. after infusion of HCl. In anaesthetized dogs, luminal immunoreactive secretin concentration increased from 2-3 to 12-16 ng/ml. after acid infusion. In both groups of dogs, a 20- to 30-fold increase in the total output of luminal immunoreactive secretin was observed. 2. Duodenal juice collected from anaesthetized dogs after diversion of both bile and exocrine pancreatic secretion was found to be the only source of luminal immunoreactive secretin. No immunoreactive secretin was found in either bile or pancreatic juice. 3. Gel filtration of the duodenal juice on a Sephadex G-50 column indicated that the immunoreactive secretin-like material in the duodenal juice possesses a molecular size similar to that of natural porcine secretin. 4. Immunoreactive secretin was partially purified from dog duodenal juice by chromatography on a SP-Sephadex column and found to be capable of stimulating pancreatic bicarbonate and water secretion in dogs.

Actions of motilin on gastrointestinal motility and plasma immunoreactive motilin concentration in interdigestive and postprandial states

Among biological actions of motilin on gastrointestinal motility, its action to induce phase III, activity front, of interdigestive myoelectric complex (IMC) appears to be of physiological significance. Synthetic motilin in a dose as little as 0.06 microgram/kg-h was shown to induce phase III in dog. A cyclic increase in fasting plasma immunoreactive motilin concentration (PIMC) occurred in phase III in dog and in a later part of phase II in man, suggesting strongly that there is an intimate relationship between cyclic increase in fasting PIMC and IMC. The observation also suggested that gastric acid secretion increases in phase II and phase III of IMC. The cyclic increase in the acid secretion may be related to a coincidental cyclic increase in PIMC. Ingestion of a meat meal results in a significant decrease in PIMC and abolishes the cyclic increase in PIMC, while IMC changes to digestive pattern after a meal. The significant decrease in PIMC is not attributed to the 3 known gut hormones including gastrin, octapeptide of CCK and secretin.

Electrogastrographic study of patients with unexplained nausea, bloating, and vomiting

A method of recording gastric myoelectric activity with a peroral suction electrode was evaluated, and the recording was compared with that obtained by implanted electrodes on the serosal surface of the stomach of laparotomized humans. In a group of patients with unexplained nausea, epigastric bloating, and vomiting, abnormal antral myoelectric activities were found by a peroral electrode, in contrast to a regular pacesetter potential (frequency: 3-4/min) in control subjects. These abnormalities were confirmed by the recordings from the implanted electrodes in the same subjects. The study indicates that peroral recording of gastric myoelectric activity is a useful diagnostic method for the detection of gastric myoelectric activity abnormalities in humans.

Lymphoma of the vitreous associated with renal transplantation and immunosuppressive therapy

A renal transplant patient presented with a uveitis unresponsive to high doses of steroids. A pars plana vitrectomy was performed for diagnosis. Light and transmission electron microscopy confirmed the diagnosis of lymphoma of the vitreous. Six percent of the renal transplant recipients develop tumors. This frequency is 100 times greater than the general population. Reticulum cell sarcoma is the predominant type being 350 times more common in renal transplant recipients than in the general population. The patient was taking immunosuppressive drugs which depress the immunologic surveillance. Antigenic neoplastic cells may arise by somatic mutations and may proliferate producing neoplasms with loss of the surveillance mechanism. The case presented illustrates that persons immunosuppressed may develop an eye tumor presenting as uveitis.

Effects of a meal and gut hormones on plasma motilin and duodenal motility in dog

Cyclic increases in the motilin level that coincided with phase III activity of interdigestive myoelectric activity of interdigestive myoelectric activity of the duodenum produced varied plasma motilin concentrations in a fasting dog. Ingestion of a meat meal not only abolished the cyclic increases in motilin concentrations, but also resulted in a significant decrease in the plasma motilin level that was accompanied by phase II-like myoelectric activity of the duodenum, a so-called digestive pattern. Although intravenous gastrin or cholecystokinin octapeptide (CCK-OP) or a combination of gastrin, CCK-OP, and secretin converted the interdigestive myoelectric activity to a digestive pattern, the cyclic increases in plasma motilin levels coulc not be changed by these hormones. This study indicates that a cyclic increase in motilin concentration occurs during the interdigestive period, but not during the digestive period. Instead, a significant decrease occurs. These changes in plasma motilin levels do not appear to be produced by three known gut hormones that are released after ingestion of a meal.

A simplified procedure for preparing innervated gastric pouches

Conventional innervated gastric pouches can be technically difficult to construct, and fistula formation between the pouch and the main stomach cavity is a common problem. This paper describes the method of construction of a small pouch on the lesser curvature (LC pouch) which we have found to be relatively free of these difficulties. Compared with the Pavlov-type pouch, this pouch gives a stronger acid secretory response to a meat meal. Furthermore, the acid secretory response was prompt to insulin hypoglycemia and sham feeding.

Polymorphism of DNA sequence in the beta-globin gene region. Application to prenatal diagnosis of beta 0 thalassemia in Sardinia

We used a restriction endonuclease to analyze the beta-thalassemia gene in Sardinia. When we digested human DNA with the restriction enzyme Bam HI, the beta-globin gene split into a 5' portion contained in a fragment of DNA 1.8 kb in length and a 3' portion in a fragment 9.3 kb in length. In some subjects, a variation in the nucleotide sequence affecting the site recognized by this enzyme on the 3' side of the beta-globin gene resulted in a different fragment, 22 kb in length, which contained the 3' portion of the beta-globin gene. In Sardinians without beta-thalassemia, the frequency of the 9.3-kb fragment was 0.67, and that of the 22-kb fragment was 0.33. In contrast, all the beta 0-thalassemia genes were associated exclusively with the 9.3-kb fragment. Thus, the beta 0-thalassemia lesion in Sardinians apparently arose on a chromosome that had the 9.3-kb Bam HI fragment. This observation can be used in prenatal diagnosis of beta 0-thalassemia in Sardina, since demonstration of the 22.0-kb fragment would indicate the normal beta-globin genotype and exclude the beta 0-thalassemia lesion on that chromosome. (N Engl J Med 302:185-188, 1980).

24-Hour plasma secretin level and pancreatic secretion in dog

Plasma secretin concentrations were determined and duodenal pH was recorded continuously for a period of 24 hours after ingestion of a meal in 3 dogs with gastric cannula and duodenal cannula and in 4 dogs with pancratic fistulae. The mean plasma secretin concentration increased significantly after a meal and it remained elevated for the first 12-hour period (peak at 30 min). Duodenal pH frequently decreased below 4.5 during the first 12-hour postprandial period, but it remained above 5.0 during the second 12 hours. Pancreatic secretion peaked during the first hour of meal ingestion and remained elevated until the end of 12 hours. The increased plasma secretin level in pancreatic fistula dog during the postprandial period was significantly greater than that of duodenal cannula dog, but the trends of increase in the secretin levels were quite identical. The present study indicates that: (1) plasma secretin concentration increases significantly within 30 min after a meal and remains increased during the first 12-hour period, (2) duodenal pH frequently decreaded below 4.5 during the same 12 hours but more frequently during the first 6 hours, and (3) a significant increase in pancreatic water, HC03- and protein occurred during the same time period.

Clinical and pathological features of six cases of sarcoidosis presenting with renal failure

Six patients with biopsy-proven renal sarcoidosis presented with renal failure of unknown origin; in none was the diagnosis of sarcoidosis initially considered. The serum creatinine concentration at the time of presentation ranged from 265 to 1380 mumol/l (3.0 to 15.6 mg/dl), with a mean of 787 mumol/l (8.9 mg/dl). Although only two patients were hypercalcemic at the time of presentation, the 24-hour urinary excretion of calcium was increased in three of the four patients in whom it was measured, and renal calculi were present in one case. Renal biopsy revealed interstitial nephritis and tubular atrophy in all cases, as well as nephrocalcinosis in three cases and noncaseating granulomas negative for acid-fast bacilli in four cases. In each patient steroid therapy led to a rapid improvement in renal function (mean post-treatment serum creatinine level 274 mumol/l [3.1 mg/dl]). The follow-up period ranged from 8 months to 8 years (mean 3.0 years). In three patients renal function remained stable with low-dose steroid therapy. In two cases recurrent hypercalcemia and deteriorating renal function accompanied steroid withdrawal but resolved with its reinstitution. In one additional case reversible deterioration in renal function accompanied tapering of the steroid dose; however, there was no hypercalcemia.This report emphasizes the importance of considering sarcoidosis in the differential diagnosis of acute renal failure of unknown origin. Long-term follow-up of such patients is essential, as relapse is common.

Influence of the vagus nerve on release and action of secretin in dog

1. The role of cholinergic nerve on plasma concentration of immunoreactive secretin and pancreatic bicarbonate secretion was investigated in conscious and anaesthetized dogs. 2. In conscious dogs with gastric and pancreatic fistulae, I.V. administration of 2-deoxy-D-glucose (2-DG) potentiated the pancreatic bicarbonate secretion stimulated by duodenal acidification. 3. In conscious dogs with same preparation, I.V. administration of atropine inhibited the pancreatic bicarbonate secretions stimulated by duodenal acidification or exogenous secretin. 4. Neither 2-DG nor atropine had any effect on endogenous release of secretin. 5. In anaesthetized dogs, pancreatic bicarbonate secretion stimulated by duodenal acidification was decreased by bilateral cervical vagotomy. However, plasma secretion concentration achieved by duodenal acidification was not different from that of pre-vagotomy state. 6. The data indicate that the changes of cholinergic tone do not affect release of endogenous secretin but alter the exocrine pancreatic bicarbonate secretion stimulated by secretin.

Capillary column gas chromatographic profile analysis of volatile compounds in sera of normal and virus-infected patients

Using a transevaporator sampling technique, the volatile profiles from 70 microliter of serum were obtained by capillary-column gas chromatography. The complex chromatograms were interpreted by a combination of manual and computer techniques and a two-peak ratio method devised for the classification of normal and virus-infected sera. Using the K-nearest neighbor approach 85.7% of the unknown samples were classified correctly. Some preliminary results indicate the possible use of the method for the assessment of virus susceptibility.

Severe hypertension after ingestion of an appetite suppressant (phenylpropanolamine) with indomethacin

Severe systemic hypertension developed in a patient who took indomethacin shortly after ingesting an appetite suppressant ('Trimolets') containing phenylpropanolamine. The hypertension was attributed to a drug interaction whereby the inhibition of prostaglandin synthesis by indomethacin exacerbated the sympathomimetic effects of phenylpropanolamine. It is suggested that withdrawal of preparations containing phenylpropranolamine from general use should be considered in view of their potential for adverse reactions with other commonly used drugs and their doubtful therapeutic value.

Enhancement of human neutrophil bactericidal activity by chemotactic factors

Neutrophils are important effector cells in the defense against microorganisms. They migrate into infected sites and then phagocytose and kill bacteria. Chemotactic factors may be important for initiating neutrophil migration. We investigated whether chemotactic factors might also influence an event subsequent to chemotaxis, namely bacterial killing. It was found that preincubation (20 min at 37 degrees C) of human leukocytes with chemotactic substances such as zymosan-activated serum, a C5a-containing fraction of zymosan-activated serum, N-formyl methionyl phenylalanine or N-formyl methionyl-leucine-phenylalanine, enhanced leukocyte killing of Staphylococcus aureus, Escherichia coli, and Streptococcus faecalis in a dose-dependent fashion. The concentration of chemotactic factor required to enhance killing was similar to that required to induce neutrophil chemotaxis. In addition, zymosan-activated serum, C5a fraction, and the two N-formyl methionyl peptides increased the hexose monophosphate shunt activity of resting and phagocytosing neutrophils by two- to threefold. In contrast, bacterial killing by sodium azide-treated neutrophils and neutrophils from a patient with chronic granulomatous disease was not increased by any chemotactic factor. These findings suggest that chemotactic factors stimulate neutrophil oxygen-dependent microbicidal pathways. These observations illustrate another important contribution of biologically active molecules to effector cell function and host defense.

Plasma secretin concentrations in fasting and postprandial states in dog

In four dogs with a modified Herrara pancreatic fistula and gastric cannula and three dogs with two duodenal cannulas, ingestion of a meat meal resulted in a significant and sustained increase in the mean plasma immunoreactive secretin concentrations, from mean fasting levels of less than 10 pg/ml to 25--55 pg/ml. This increase in the plasma secretin concentration coincided with a marked increase in pancreatic bicarbonate output and frequent decreases in the mean proximal duodenal pH to less than 4.5 from the range of 6.5 in the fasting state. Intravenous administration of cimetidine, 150 mg, produced a marked suppression of postprandial increases in both pancreatic bicarbonate output and plasma secretin concentration. Moreover, the postprandial duodenal pH rarely reached below 5.0 after cimetidine administration. These studies indicate that plasma secretin concentration does increase significantly after a meal. The postprandial increase in plasma secretin concentration appears to depend on the gastric acid delivered in the proximal duodenum. A possible physiological role of secretin in the pancreatic secretion after a meal is indicated by these findings.

Crystal structure and molecular interactions of tropomyosin

The three-dimensional structure of tropomyosin filaments has been determined by X-ray crystallography. The ends of the molecules were located by reference to the single pair of cysteine residues. Departures from the alpha-helical-coiled coil conformation may occur in localised domains along the molecule as well as at the overlapping ends.

Simultaneous determination of antiarrhythmia drugs by high-performance thin-layer chromatography

A method is described for the determination of antiarrhythmia drugs in serum by high-performance thin-layer chromatography. Baseline separations are achieved for all the drugs and clozapine, an internal standard, in two developments with solvents of different polarity. Lidocaine and diphenylhydantoin are scanned at 220 nm after the first development. Procainamide, propranolol and quinidine are scanned at 290 nm after the second development. The relative standard deviation of the determination varies between 3 and 14% depending on the nature of the drug and its concentration.

Effects of motilin and octapeptide of cholecystokinin on antral and duodenal myoelectric activity in the interdigestive state and during inhibition by secretin and gastric inhibitory polypeptide

In conscious dogs prepared with gastric cannulae and antral and duodenal electrodes, intravenous administration of synthetic porcine motilin and CCK-OP in varying doses resulted in significant increases in the mean percent frequency of spike potentials on slow waves. Motilin was a more potent stimulant than CCK-OP. Motilin-stimulated spike potentials in both antrum and duodenum were significantly suppressed by either natural porcine secretin or synthetic porcine GIP. Secretin suppressed the spike potentials of the antrum stimulated by CCK-OP but not those of the duodenum. The spike potentials stimulated by CCK-OP could not be suppressed by GIP in the dosages employed.

Effect of metal ions on growth and sporulation of Clostridium perfringens in a synthetic medium

All cells, whatever their origin, function in an essentially inorganic environment. In this environment, metal cations play an important role. Attempts were made in the present study to determine if different amounts of five metal ions (MG++, Fe++, Mn++, Zn++, Ca++) are needed for secondary metabolism of Clostridium perfringens than are needed for primary metabolism. Both the vegetative growth stage (primary metabolic stage) and spore stage (secondary metabolic stage) of Clostridium perfringens were studied. Endeavors were made to detect the effects of metal ions, if any, on growth and sporulation of the organisms. Mg++ was required for growth of vegetative cells and maintenance of normal cellular morphology, Fe++ was needed for sporulation as well as for vegetative growth, but the amount needed for spore formation was higher than that needed for growth. Ca++ was essential to refractility and heat-resistance of spores. Zn++ inhibited both growth and sporulation, if the Mg++ concentration was low. Mn++ was required for neither growth nor sporulation. For maximum heat-resistance of the spores, Ca++ plus unidentified organic substances were required.

The nature of molybdenum-cofactor

In vitro assembly of Neurospora crassa NADPH-nitrate reductase (EC1.6.6.2) could be effected by combing the nitrate induced Neurospora crassa mutant nit-1 with the extract of any known molybdenum-containing enzyme. The process involves the participation of a molybdenum-cofactor contributed by the molybdenum-enzyme fraction. This paper emphasizes two points: Firstly, the indispensable role played by EDTA in the viability of Mo-cofactor and secondly, the nature of Mo-cofactor predicated by our previous work is supported by concrete experimental results. Recent experiments with Chelax-100 column provide evidence that the in vitro formation of Neurospora NADPH-nitrate reductase involves EDTA and the latter may take part in the formation of a molybdenum, labile sulfide and EDTA complex. In addition to 10(-2) M sodium molybdate, both EDTA and reducing agent are required to activate the cofactor in the Chelax-100 column eluate. The cofactor is of low molecular weight and devoid of protein as was predicated. To substantiate those predications, concrete experimental results are provided.

Inhibition of the biologic effects of endotoxin on neutrophils by polymyxin B sulfate

Polymyxin B sulfate diminished the endotoxin-mediated release of human blood neutrophil lysosomal enzymes. Similarly, this antibiotic reduced the endotoxin-induced increase in the neutrophil hexose monophosphate pathway activity as measured by the release of 14CO2 from [l-14C]glucose. Although these effects were seen with therapeutically attainable levels of polymyxin B sulfate, they could not be demonstrated when the cell-endotoxin interaction preceded treatment with polymyxin B sulfate.