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Atmospheric climate monitoring requires observations of high quality that conform to the criteria of the Global Climate Observing System (GCOS). Radio occultation (RO) data based on Global Positioning System (GPS) signals are available since 2001 from several satellite missions with global coverage, high accuracy, and high vertical resolution in the troposphere and lower stratosphere. We assess the consistency and long-term stability of multi-satellite RO observations for use as climate data records. As a measure of long-term stability, we quantify the structural uncertainty of RO data products arising from different processing schemes. We analyze atmospheric variables from bending angle to temperature for four RO missions, CHAMP, Formosat-3/COSMIC, GRACE, and Metop, provided by five data centers. The comparisons are based on profile-to-profile differences aggregated to monthly medians. Structural uncertainty in trends is found to be lowest from 8 to 25 km of altitude globally for all inspected RO variables and missions. For temperature, it is

In this paper, we introduce a bending angle radio occultation climatology (BAROCLIM) based on Formosat-3/COSMIC (F3C) data. This climatology represents the monthly-mean atmospheric state from 2006 to 2012. Bending angles from radio occultation (RO) measurements are obtained from the accumulation of the change in the raypath direction of Global Positioning System (GPS) signals. Best quality of these near-vertical profiles is found from the middle troposphere up to the mesosphere. Beside RO bending angles we also use data from the Mass Spectrometer and Incoherent Scatter Radar (MSIS) model (modified for RO purposes) to expand BAROCLIM in a spectral model, which (theoretically) reaches from the surface up to infinity. Due to the very high quality of BAROCLIM up to the mesosphere, it can be used to detect deficiencies in current state-of-the-art analysis and reanalysis products from numerical weather prediction (NWP) centers. For bending angles derived from European Centre for Medium-Range Weather Forecasts (ECMWF) analysis fields from 2006 to 2012, e.g., we find a positive bias of 0.5 to 1% at 40 km, which increases to more than 2% at 50 km. BAROCLIM can also be used as a priori information in RO profile retrievals. In contrast to other a priori information (i.e., MSIS) we find that the use of BAROCLIM better preserves the mean of raw RO measurements. Global statistics of statistically optimized bending angle and refractivity profiles also confirm that BAROCLIM outperforms MSIS. These results clearly demonstrate the utility of BAROCLIM.

Asymptotic methods of calculating the propagation of centimeter radio waves in a neutral atmosphere in space-space paths are considered. The methods are based on the technique of Fourier integral operators. The approximations that allow the representation of the corresponding operators as compositions of nonlinear coordinate changes, multiplications by reference signals, and Fourier transformations are constructed. The approximations are based on a technical procedure using a linearized canonical transform. This approach makes it possible to devise fast numerical algorithms. Numerical simulations are conducted with the use of realistic global gridded fields of meteorological parameters including the turbulence. The numerical simulations show high accuracy and efficiency of the proposed methods.

We investigate algorithms for filtering noisy radio occultation data with atmospheric multipath behavior in order to improve the accuracy of the inversion based on canonical transform/full spectrum methods. The noise filtering procedure uses the compression of the signal spectrum by multiplying it with a reference signal, Fourier filtering of the narrow-banded signal, and decompression of its spectrum.We study filtering in the time domain and in the impact parameter domain. Our results show that the inversion methods are able to handle additive white noise and high resolution bending angle profiles are obtained. For comparison we also present results where the inversion of multipath behavior is based on using phase data only.

We discuss the recent achievements in the application of asymptotic methods based on Fourier Integral Operators (FIOs) for inversion and direct modeling of radio occultations. We show that FIOs can be derived from the first principles: stationary phase principle and energy conservation. We discuss accurate and approximate solutions for the kernel of the FIOs. The approximations can be used for designing very efficient numerical algorithms, where the FIOs are reduced to a composition of multiplying with reference signals and Fourier transforms. Another application is inversion algorithms using an FIO that retrieves the geometric optical ray structure of wave fields. Asymptotic methods of forward modeling are based on inverse FIOs that map the geometric optical ray structure to wave fields. Such algorithms are very fast and significantly reduce numerical inaccuracies, which arise in computation of multiple diffractive integrals.

In the present work, we study a canonical transform that directly maps the measured field to the impact parameter representation without first carrying out a back-propagation. This canonical transform is determined to first order in a small parameter that measures the deviation of the satellite orbit from a circle. When the parameter is equal to zero, i.e., for circular orbits, our canonical transform reduces to a Fourier transform. In the general case, the form of the generating function is such that it does not directly allow an implementation as an FFT-like algorithm. However, using approximations the direct canonical transform mapping yields fast, efficient numerical implementations.

A patient with bleeding from the eroded distal splenic artery secondary to acute pancreatitis is presented. The pancreatic tail was found to be moderately edematous without cyst, abscess or necrosis at splenectomy. The walls of the artery showed no structural changes. The postoperative course was uneventful.

The effect of bilateral orchidectomy in relieving pain in 70 patients with metastatic carcinoma of the prostate was investigated by review of the case reports of a patient material from a urological department. 74% of the patients stated that the intervention was effective. Relief of pain lasting for more than seven months and attributable solely to the orchidectomy occurred in 19%. It did not prove possible to differentiate by means of biochemical or clinical parameters between the patient groups with and without beneficial effects from the intervention. 30% died during the first postoperative year. The five year survival rate was calculated to be 19%.

Severe fasting hypoglycemia and hypoinsulinemia occurred in a sixty-six year old woman with an intrahepatic mesenchymal tumor. An extract from the tumor was potent in inhibiting the arginine-induced glucagon secretion from the isolated perfused porcine pancreas. This observation supports the theory recently advanced that mesenchymal tumor hypoglycemia in some cases is due to a still unknown factor secreted from the tumor, which directly inhibits pancreatic glucagon secretion.

The effect of intraduodenal infusion of amino acids, glucose, fat, HCl, ethanol, or saline on plasma VIP concentration was investigated in 7 normal subjects, 5 post-vagotomy patients, and 12 anaesthetized pigs. Furthermore, the concentrations of VIP in plasma after ingestion of a mixed meal were measured in 6 normal subjects. In normal subjects the median peripheral concentration of VIP in the basal state was 4.3 pmol X I-1 (range 0--12.0). No significant changes occurred after amino acids, glucose, saline, or ingestion of a meal. In contrast infusion of HCl, fat, or ethanol resulted in a rise in plasma VIP concentration in all the subjects studied. The peak values (medians and ranges) after HCl, fat, or ethanol were 9.8 (5.9--12.6), 7.5 (2.4--10.2), and 12.6 (7.8--16.8)pmol X I-1, respectively. Truncal vagotomy did not change the response of HCl. The results from measurements in portal plasma of pigs confirmed the findings in peripheral plasma of normal subjects and showed that the levels of VIP in portal plasma are 1.6--2.9 times higher than the levels of VIP in arterial plasma. The pH threshold to release of VIP was pH 1.1--2.1, and the effect of HCl was not abolished by ganglionic blockade.

The gastro-entero-pancreatic (GEP) hormone response to glucose ingestion is considerably altered in pregnancy in normal women and gestational diabetics. In normal women, also the GEP hormone response to protein is changed in pregnancy. In the present investigation, the gastrin, gastric inhibitory polypeptide (GIP), gut glucagon-like-immunoreactivity (gut GLI), insulin, pancreatic glucagon, and pancreatic polypeptide (PP) responses to a protein rich meal in pregnancy and postpartum were studied in 10 women with gestational diabetes. Five of the women were overweight and five were normal weight. Fasting and postprandial gut GLI and PP levels were reduced and insulin levels enhanced in pregnancy. No effect of pregnancy on fasting or postprandial gastrin, GIP, or glucagon levels was found. In pregnancy as well as postpartum, insulin levels were higher in the overweight than in the normal weight patients, whereas the concentrations of the other hormones were similar in the two subgroups of gestational diabetics. It is concluded that the GEP hormone response to a protein rich meal is influenced by late pregnancy in gestational diabetics in the same way as in normal women. The physiological consequences of the findings are not known in detail as yet but they may be important to carbohydrate metabolism and gastrointestinal physiology in pregnancy.

Enteroglucagon concentration in peripheral blood was determined before and after a test meal in 24 morbidly obese patients. Eighteen had jejunoileal bypass, 6 with a 3:1 and 12 with a 1:3 jejunoileal ratio of the functioning segment, and 6 were unoperated. All three groups exhibited an increment of enteroglucagon concentration after the meal. Both the fasting values and the postprandial integrated increments were higher in operated patients than in unoperated patients and higher after 1:3 bypass than after 3:1 bypass. The findings agree with the hypothesis that enteroglucagon secretion is stimulated by exposure of the lower bowel to upper-bowel content, and that the effect of enteroglucagon is, as seen after bypass operation, stimulation of growth and reduction of motility of the intestine.

We previously showed that basal and pentagastrin-stimulated gastric acid secretion, gastrin in serum and gastrin in antral mucosa were significantly greater in patients with Roux-Y hepaticojejunostomy than in those with choledochoduodenostomy. These findings prompted investigation of basal secretion of gastric inhibitory polypeptide (a peptide with an enterogastrone as well as an insulinogenic effect), insulin and glucose in the same patients. Basal gastric inhibitory polypeptide was significantly lower in patients with Roux-Y hepaticojejunostomy than in those with choledochoduodenostomy, whereas glucose and insulin did not differ in the two groups. No correlation could be demonstrated between gastric inhibitory polypeptide, gastric acid secretion and gastrin, suggesting that hyposecretion of gastric inhibitory polypeptide is not a pathogenetic factor for the hypersecretion of gastric acid secretion in patients with Roux-Y hepaticojejunostomy. Hyposecretion of gastric inhibitory polypeptide and gastric acid hypersecretion in patients with bile diversion seem to be two independent phenomena.

The diagnostic power of combined cholescintigraphy and ultrasonography was tested in 67 patients suspected of having acute cholecystitis; of these, 42 (63%) had acute cholecystitis. The predictive value of a positive scintigraphy (PVpos) was 95% and that of a negative (PVneg) was 91% (n = 67). The PVpos and PVneg of ultrasonography were 89% and 75%, respectively (n = 54), and these values did not achieve statistical significance when compared with those for scintigraphy. Inconclusive tests were 10% and 11%, respectively, but in no patient were both scintigraphy and ultrasonography inconclusive. PVpos and PVneg of combined scintigraphy and ultrasonography were 100% when the two test results were identical (n = 34). In patients with one test inconclusive or discrepancy between scintigraphy and ultrasonography, PVpos and PVneg were 79% and 67%, respectively (n = 20). The results suggest that in patients suspected of having acute cholecystitis cholescintigraphy should be the first diagnostic procedure performed. If the scintigraphy is positive, additional ultrasonographic detection of gallstones makes the diagnosis almost certain. If one diagnostic modality is inconclusive, the other makes a fair basis for diagnostic and therapeutic decision. In case of discrepancy between ultrasonography and scintigraphy the diagnosis should be reevaluated.

It has been shown that the incretin effect - i.e. the gastrointestinal potentiation of the insulin response to oral glucose - is reduced in late normal pregnancy. As evidence points to gastric inhibitory polypeptide (GIP) as mediator of at least part of the incretin effect, the GIP response was determined following a 50 g oral glucose load in 6 normal women in the last trimester of pregnancy and again post partum. Compared to post partum the GIP response to oral glucose was significantly impaired in late pregnancy. It is concluded that the diminished GIP response to oral glucose in late pregnancy might at least partly explain the impaired incretin effect found in this condition.

An oral glucose tolerance test (OGTT), an OGTT after infusion of anti-gastric inhibitory polypeptide (GIP) serum, and an intravenous glucose infusion were performed in unrestrained and unanesthetized rats. In the rats treated with anti-GIP serum the insulin release was significantly depressed. This finding supports the concept that GIP is a physiologically important ‘glucose-dependent insulin-releasing peptide’.

Fifty patients with cirrhosis of the liver had gastrin concentrations in serum above normal when measured in the fasting state. Hypergastrinaemia predominated in non-alcoholic cirrhosis. In both groups of patients, serum gastrin levels were higher in patients with inactive cirrhosis than when cirrhosis was slightly active.

Ten male patients, recovered from acute myocardial infarction, and ten control subjects were investigated by a 50 g oral glucose tolerance test. All patients and control subjects had normal glucose tolerance, but the patients had increased fasting and integrated insulin response to oral glucose. Fasting gastric inhibitory polypeptide concentrations and integrated gastric inhibitory polypeptide response were normal in the patients. The exaggerated insulin secretion in patients recovered from myocardial infarction does not seem to be caused by increased secretion of gastric inhibitory polypeptide.

The insulin response to oral glucose ingestion was measured in six patients with the Zollinger-Ellison (ZE) syndrome, five patients with partial gastrectomy (antrectomy for duodenal ulcer) and six matched normal subjects. The blood glucose curves were similar in ZE-patients and gastrectomized controls and significantly above the glucose concentrations in normal controls. The insulin response was three-doubled in ZE-patients, whereas gastrectomized controls only doubled their response in comparison with the normal subjects. Treatment of a hepatic gastrinoma by streptozotocin infusion into the hepatic artery in a patient with diabetes mellitus and hyperinsulinism almost normalized his glucose tolerance and insulin secretion. The results demonstrate that the ZE-syndrome is associated with increased insulin release. We suggest that the hyperinsulinism partly is a consequence of previous gastric surgery and partly due to the insulinogenic effect of gastrin.

Orthopantomography of the mandible was carried out on 50 patients with colorectal cancer without known familial disposition. Twelve patients (24%) had osteomas, as against 5% in the control group (P less than 0.001). Since an increased occurrence of mandibular osteomas has earlier been demonstrated in cases of familial polyposis coli and the family cancer syndrome, we must conclude that genetic factors are presumably of more importance in the development of colorectal cancer than previously assumed.

Fifteen patients in whom various parts of the small intestine had been resected because of Crohn's disease or mesenteric thrombosis and 10 healthy volunteers were studied. A 50-g oral glucose load (OGTT) and an intravenous glucose infusion giving the same plasma glucose profile as the OGTT were carried out to study (a) the relation between the plasma gastric inhibitory polypeptide (GIP) levels after oral glucose and the length and nature of the intestinal residues and (b) the importance of endogenous GIP as an incretin in man. The magnitude of the increase in plasma GIP after oral glucose load was positively correlated to the length of residual jejunum. The incretin effect was positively correlated to the length of residual intestine. Patients with preserved ileal residues had larger incretin effects than patients with less than 150 cm jejunal residues and no ileal residues, although the integrated increases in plasma GIP after oral glucose were equal. Compared with healthy volunteers, the patients with more than 150 cm residual jejunum had significantly higher increases in plasma GIP and normal incretin effects. The GIP release and the incretin effect in patients with preserved ileal residues were normal. The incretin effect of the patients with less than 150 cm jejunum was significantly subnormal in spite of a normal GIP release. These findings indicate that the upper intestine releases GIP after oral glucose and that other as yet unknown intestinal hormonal factors act as incretins in concert with GIP.

Several studies report that placenta and amniotic fluid (AF) may be a source of many peptide hormones. Although the presence of gastric inhibitory polypeptide (GIP) in amniotic fluid has not been described, it is present in the fetal gut. In this study we report the presence of insulin and GIP in human AF of normal and diabetic pregnancies. GIP concentrations in the AF collected two hours after an arginine tolerance test (ATT), at 34-36 weeks of gestation, were evaluated in 8 normal and 53 diabetic pregnant women. GIP was found in all samples of AF. The mean AF-GIP concentrations were 133 +/- 19 pmol/l in controls and 111 +/- 6 pmol/l in the diabetics, being the GIP values of the diabetics belonging to White Class B significantly lower than those of normals (99 +/- 10 vs 133 +/- 19 pmol/l). The GIP/IRI molar ratio was significantly lower in the diabetics than in controls (1.2 +/- 0.2 vs 2.5 +/- 0.4); moreover the GIP/IRI molar ratio was significantly higher in AF collected from diabetic pregnant women who delivered overweight infants than in AF of normal weight infants or controls. This finding would suggest a negative feedback mechanism between GIP and insulin in fetus.

Forty-seven patients having dysplasia in biopsies from the gastric mucosa were subjected to re-investigation. Twenty-three patients were alive at follow-up and 14 underwent gastroscopy with removal of random biopsies. The median duration of observation was 39 months, range 10-63 months. Regression of the dysplasia was found in all patients; in nine there was normal mucosa without dysplastic alterations in the control biopsies, mild dysplasia was still present in five of the patients. Our results suggest that the incidental finding of mild or moderate dysplasia does not, per se, indicate the necessity of further control, whereas severe dysplasia indicates repeat gastroscopies with biopsies, as such epithelial changes can occur together with gastric carcinoma.

Nine patients were studied 1.5--3 years after jejuno-ileostomy for obesity by an intravenous glucose infusion technique designed to imitate blood glucose concentrations after glucose ingestion. Whereas serum insulin and gastrin concentrations were normal, blood glucose concentrations were significantly depressed compared to preoperative levels as well as to levels in matched normal subjects. Thus, in the fasting state mean concentrations (+/- S.E.M.) of blood glucose, serum insulin and gastrin in the patients were, respectively, 3.3 +/- 0.2 mmol/l, 95 +/- 22 pmol/l and 38 +/- 4 pmol/l. The corresponding concentrations in the matched normals were 4.3 +/- 0.2 mmol/l, 70 +/- 18 pmol/l and 39 +/- 6 pmol/l. The glucose concentrations in the patients were low in all situations, i.e. in the fasting state, after oral glucose ingestion and during the intravenous glucose infusion. The results indicate that jejuno-ileostomy in obesity greatly facilitates peripheral glucose disposal. The mechanism behind this phenomenon is not yet known.

The correlation between the peripheral concentrations of gastric inhibitory polypeptide (GIP), insulin, and glucose has not previously been quantified. This paper describes the association among the peripheral concentrations of GIP, insulin, and glucose during 50-g oral glucose tolerance tests (OGTT) in healthy volunteers and in patients with gastrointestinal disorders, obesity, and uremia. It was found that the correlation between insulin/glucose and plasma GIP concentrations during an OGTT can be expressed by the equation: log y = log a + bx, where y = [insulin]/[glucose], and x is the plasma GIP concentration. This empirical correlation between [insulin]/[glucose] and [GIP] reduces the plasma parameters measured during OGTT to a simple relationship. It may prove valuable in the analysis of differences in the relationship glucose-insulin-GIP between groups of subjects and in the description of alterations in glucose homeostasis longitudinally in individuals undergoing therapy.

Ten psychiatric patients were given a protein-rich meal in periods on and off lithium administration. The concentrations of gastrin in serum were measured radioimmunochemically before and during the meal. The results show that lithium suppresses basal as well as food-stimulated gastrin secretion.

The responses of gastric inhibitory polypeptide (GIP) and insulin to intraduodenal and IV triglyceride infusions were measured in 11 late fetal and 10 neonatal pigs. Basal plasma glucose, insulin, and GIP concentrations were lower in fetal than in neonatal pigs. In the fetal pigs, plasma glucose increased slightly during intraduodenal and IV triglyceride infusions, whereas plasma insulin remained unchanged during the tests. No significant changes were observed in plasma GIP concentration following intraduodenal triglyceride infusion in the fetal pigs, but plasma GIP fell during the IV infusion of triglyceride in these pigs (p less than 0.01). In the neonatal pigs, plasma glucose and insulin remained unaffected by intraduodenal and triglyceride infusions. Plasma GIP did not change during the IV triglyceride infusion, but exhibited a paradoxical decline after the intraduodenal triglyceride infusion (p less than 0.05). It is concluded that the GIP-cell response to an oral triglyceride load is suppressed in late fetal and neonatal pigs. The abolished GIP response to oral triglycerides could play a causal role in the inactivity of the enteroinsular axis which is seen in both human and animal neonates.

Twelve morbidly obese patients and 17 patients treated for obesity by jejunoileal shunt operation were studied. A 50-g oral glucose load (OGTT) and an intravenous glucose infusion were carried out to study a) the relation between the plasma gastric inhibitory polypeptide (GIP) levels after oral glucose and the type of jejunoileal bypass performed and b) the importance of endogenous GIP as an incretin in man. The GIP release during OGTT and incretin effect were normal in the obese patients. After jejunoileal shunt, measuring 48 cm and with a ratio of 3:1 between the jejunal and ileal segments, the GIP release and the incretin effect were significantly reduced. Incremental increase in plasma GIP and OGTT was significantly correlated to the incretin effect in these patients. After jejunoileal shunt with the reverse ratio of proximal and distal intestine the incretin effect was significantly higher in spite of a comparable GIP release. Five patients after ileoascendostomia for familial hypercholesterolemia had significantly supernormal GIP release during OGTT but normal incretin effect. The findings indicate the insulinotropic effect of GIP and are in accordance with the concept that incretins other than GIP are released from the distal intestine.

Eight patients with biopsy-verified coeliac disease were investigated after remission on a gluten-free diet. A 50-g oral glucose load (OGTT) and an intravenous glucose infusion (IVGI) giving the same plasma glucose profile as the OGTT were carried out. The relation between gastric inhibitory polypeptide (GIP) plasma levels after oral glucose and the insulin release during OGTT and IVGI were studied. Plasma GIP concentration in the fasting state and the increase in plasma GIP during OGTT were significantly lower than in a group of eight healthy volunteers. However, the insulin potentiation during OGTT, the incretin effect, was normal. The results indicate the existence of other incretins than GIP. These are probably released from the distal small bowel in patients with coeliac disease.

The responses of gastric inhibitory polypeptide (GIP) and insulin to intraduodenal (OGTT) and iv (IVGI) glucose infusions were measured in 14 late fetal and 9 neonatal pigs. Basal plasma glucose (P0.01) and GIP (P0.001) concentrations were lower in the fetal than in the neonatal pigs, while basal plasma insulin was not significantly different in the two groups. In the fetal pigs, almost identical plasma glucose curves were obtained during the OGTT and the IVGI, but plasma insulin did not change during either test. In these pigs, plasma GIP increased 3-fold (P0.01) during the OGTT, whereas no significant changes in plasma GIP were observed during the IVGI. In the neonatal pigs, plasma glucose increased more during the OGTT than during the IVGI, but plasma insulin exhibited similar increments during both tests. Thus, the insulinogenic index of the IVGI was almost 3 times higher than that of the OGTT (P0.05). In contrast to the normal increment in plasma GIP observed in fetal pigs, plasma GIP decreased significantly during both tests in the neonatal pigs. It is concluded that beta-cells of fetal pigs are unresponsive to acute elevations of plasma glucose with or without a concomitant increase in plasma GIP. Conversely, beta-cells of neonatal pigs exhibit a significant response to hyperglycemia, but the enteroinsular axis is defective, since more insulin is released after iv than during intraduodenal glucose administration. The defective enteroinsular axis in neonatal pigs might be due to the observed fall in plasma GIP during the OGTT.