Metabolic and hormonal studies of Type 1 (insulin-dependent) diabetic patients after successful pancreas and kidney transplantation

Long-term normalization of glucose metabolism is necessary to prevent or ameliorate diabetic complications. Although pancreatic grafting is able to restore normal blood glucose and glycated haemoglobin, the degree of normalization of the deranged diabetic metabolism after pancreas transplantation is still questionable. Consequently glucose, insulin, C-peptide, glucagon, and pancreatic polypeptide responses to oral glucose and i.v. arginine were measured in 36 Type 1 (insulin-dependent) diabetic recipients of pancreas and kidney allografts and compared to ten healthy control subjects. Despite normal HbA1 (7.2±0.2%; normal <8%) glucose disposal was normal only in 44% and impaired in 56% of the graft recipients. Normalization of glucose tolerance was achieved at the expense of hyperinsulinaemia in 52% of the subjects. C-peptide and glucagon were normal, while pancreatic polypeptide was significantly higher in the graft recipients. Intravenous glucose tolerance (n=21) was normal in 67% and borderline in 23%. Biphasic insulin release was seen in patients with normal glucose tolerance. Glucose tolerance did not deteriorate up to 7 years post-transplant. In addition, stress hormone release (cortisol, growth hormone, prolactin, glucagon, catecholamines) to insulin-induced hypoglycaemia was examined in 20 graft recipients and compared to eight healthy subjects. Reduced blood glucose decline indicates insulin resistance, but glucose recovery was normal, despite markedly reduced catecholamine and glucagon release. These data demonstrate the effectiveness of pancreatic grafting in normalizing glucose metabolism, although hyperinsulinaemia and deranged counterregulatory hormone response are observed frequently

Air-flow geometry in air sparging of fine-grained sands

Laboratory visualization experiments in fine- to very fine-grained sands (grain diameter <0.21 mm) reveal a previously unrecognized air-flow geometry. This air-flow geometry is termed "chamber flow" and is characterized by: (1) a significant horizontal component, (2) pervasive air-flow coverage within a region demarcated by a distinct, irregular boundary, and (3) the presence of predominantly vertical inlet and outlet channels. The attributes of chamber flow differ significantly from channelized flow and pervasive/bubbly flow, which occur at larger grain sizes and have been described in the literature by several researchers. Previous research, which indicates a dramatic increase in contaminant removal time in sediments <0.2 mm, indirectly corroborates the phenomena observed in this study. The extent of sediment column affected by chamber flow of sparge air ranges from 4–54% on an area basis, and is approximately 28% on a volume basis. These values indicate that chamber air flow has the potential to affect a much larger percentage of the sediment column than either channelized or pervasive/bubbly flow. Because of the irregularity of air-flow chambers, in terms of both form and frequency, a detailed knowledge of stratigraphy is important to maximize air-sparging efficiency at sites where chamber flow is likely to occur. Des expériences de visualisation en laboratoire dans des sables à grains fins à très fins (diamètre des grains inférieur à 0,21 mm) ont mis en évidence une géométrie des écoulements d'air non reconnue auparavant. Cette géométrie des écoulements d'air est nommée «écoulement en cavité» et est caractérisée par (1) une composante horizontale significative, (2) un domaine d'expansion de l'écoulement d'air dans une région délimitée par une frontière distincte et irrégulière, et (3) la présence de chenaux essentiellement verticaux d'entrée et de sortie. Les caractères de l'écoulement en cavité diffèrent significativement de l'écoulement en chenaux et de l'écoulement expansif en bulle, qui se produisent pour des tailles de grains plus grandes et qui ont été décrits dans la littérature par plusieurs chercheurs. Une étude antérieure, qui indique un accroissement considérable du temps de déplacement d'un polluant dans des sédiments de granulométrie inférieure à 0,2 mm, confirme indirectement les phénomènes observés dans ce travail. La part de la colonne de sédiment affectée par l'écoulement en cavité de l'air poussé et injecté va de 4 à 54% par rapport à la surface, et est d'environ 28% en volume. Ces valeurs indiquent que l'écoulement d'air en cavité a la capacité d'affecter une part de la colonne de sédiment bien plus vaste que l'écoulement en chenaux ou en bulles expansives. À cause de l'irrégularité des cavités d'écoulement d'air, à la fois en termes de forme et de fréquence, une connaissance détaillée de la stratigraphie est importante afin que l'injection de l'air soit maximale à des sites où il est probable que l'écoulement en cavité se produise. La visualización de experimentos de laboratorio con arenas de tamaño de grano fino a muy fino (diámetro de grano inferior a 0,21 mm) revela la existencia de una geometría de flujo de aire que no se había identificado previamente. Esta geometría es denominada "flujo en cámara" y se caracteriza por: (1) una componente horizontal significativa, (2) la cobertura generalizada del flujo de aire dentro de una región delimitada por un contorno distinto e irregular, y (3) la presencia de canales predominantemente verticales en las zonas de entrada y salida. Los atributos del flujo en cámara difieren significativamente del flujo en canales y el flujo generalizado/de burbujas, los cuales tienen lugar con tamaños mayores de grano y han sido descritos en la literatura por diversos investigadores. Las investigaciones previas, que indican un aumento enorme en el tiempo de descontaminación necesario para sedimentos de tamaño inferior a 0,2 mm, corroboran de forma indirecta los fenómenos observados en este estudio. La zona afectada por flujo en cámara durante la inyección de aire en la columna de sedimentos varía entre el 4 y el 54% en área, lo cual equivale aproximadamente al 28% en volumen. Estos valores indican que el flujo en cámara de aire tiene el potencial de afectar a un porcentaje de la columna mucho mayor que los otros mecanismos de flujo. Debido a la irregularidad de las cámaras de flujo de aire, tanto en forma como en frecuencia, es importante adquirir un conocimiento detallado de la estratigrafía para maximizar la eficacia de la inyección de aire en lugares en los que es probable el desarrollo de flujo en cámara.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42337/1/10040-9-2-168_s100400000104.pd

Psychological and physiological predictors of lipids in black males

The association between lipids and both psychological and physiological measures were examined in this study of healthy black males. The results revealed that certain psychological measures, namely, State and Trait Curiosity and Trait Anger, explained a significant proportion of the variance in high-density lipoproteins (HDL), low-density lipoproteins (LDL), and triglycerides. Although psychological factors accounted for a significant proportion of the variance in lipids (29% for HDL, 25% for LDL, 64% for LDL/HDL, 29% for triglyceride), the amount of explained variance was significantly increased by the inclusion of both psychological and physiological variables in the regression equation. However, neither of the psychological variables explained any of the variance for total cholesterol when physiological variables were included in the regression analysis. The overall pattern of the findings suggests that black males who are at increased risk for elevated lipid levels may be identified by their level of mental vigilance, the frequency at which their anger is experienced, and the presence of other traditional risk factors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44812/1/10865_2004_Article_BF00845357.pd

Phaeochromocytoma and functioning paraganglioma in childhood and adolescence: role of iodine 131 metaiodobenzylguanidine

Phaeochromocytomas and functioning paragangliomas are rare tumours in childhood and adolescence. We review our experience of 43 cases (24 men, 19 women) who were first diagnosed at the age of ⩽ 18 years. All patients were evaluated at some point in their illness with iodine 131 metaiodobenzylguanidine ( 131 I-mIBG) scintigraphy. Eight patients (19%) had bilateral adrenal tumours, 12 (28%) had solitary extra-adrenal tumours, and 8 (19%) had multiple tumours. In 10 patients (23%), the tumours were associated with a familial neurocristopathic syndrome. Thirteen of 24 (54%) unifocal tumours which were initially considered to be benign ultimately proved to be multi-focal and/or malignant. The final prevalence of malignancy was 60% − 26 patients, of whom only 15 (57%) had obviously malignant tumours at the time of diagnosis. Primary tumour size ⋝5 cm was more commonly associated with a malignant course in adrenal but not extra-adrenal tumours. No other clinical, biochemical or morphological characteristic was significantly associated with malignancy. Although the high prevalence of malignancy in this series at least partly reflects referral bias, the need for lifelong follow-up of these patients is underscored. 131 I-mIBG scintigraphy was positive in 36 patients (84%), with a somewhat lower false-negative rate (12%) than X-ray computed tomography (20%). Eight patients with malignant tumours received therapeutic doses of 131 I-mIBG, with partial tumour responses in 3. Thus, 131 I-mIBG is an efficacious, non-invasive, localising agent and may be considered as a palliative therapeutic agent when alternatives have failed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46831/1/259_2005_Article_BF02262730.pd

Plasma gut hormone levels in 37 patients with pheochromocytomas

Pheochromocytomas are usually recognized by the effects of overproduction of catecholamines, but there are clinical features that cannot be ascribed to catecholamine excess that may be due to vasoactive peptides. We, therefore, measured blood levels of vasoactive intestinal peptides (VIP), substance P, somatostatin (SS), and motilin in 50 instances in 37 patients with pheochromocytomas-21 malignant, 10 benign intra-adrenal, and 6 ectopic (5 paracardial and 1 perirenal). Hormone levels were considered raised if the level was more than 3 S.D. above the mean value found in 52 healthy subjects. Of the 37 patients, 20 (54%) had an abnormality in 1 or more gut hormone levels. The most common abnormality was a raised SS in 9/37 (24%). In addition to these, however, 3 (8%) others had raised VIP, 5 (13.5%) raised motilin, and 3 (8%) raised substance P. Patients with benign adrenal adenomas had raised levels of SS and substance P. Ectopic pheochromocytomas produced only SS in addition to catecholamines, but malignant pheochromocytomas could secrete all 4 peptides, and more than 1 in the same patient. We conclude that pheochromocytomas may secrete multiple vasoactive peptides, and they are more likely to do so if malignant. Somatostatin is the most commonly secreted peptide and is found with benign adrenal and ectopic (paracardiac) tumors. If the level of more than 1 peptide is elevated, the likelihood of malignancy is significantly increased . Les phéochromocytomes sont généralement déceléspar les effets dûs à la surproduction de catécholamines, mais certains troubles ne peuvent être attribués à ce phénomène et relèvent peut être de l'action de peptides vasoactifs. Les auteurs se sont donc attachés à doser dans le sang le VIP, la substance P, la somatostatine (SS), et la motiline. Ces dosages furent pratiqués 50 fois chez 37 malades porteurs de phéochromocytomes: 21 malins, 10 bénins et 6 ectopiques (5 paracardiaque et 1 péri-rénal). Les taux des hormones furent considérés comme élevés lorsque leur niveau fut supérieur à plus de 3 fois le taux de 52 sujets sains. Sur les 37 malades 20 (54%) présentaient un excès d'une ou de plusieurs hormones digestives. L'anomalie constatée la plus fréquente fut l'élévation de la SS (9 fois sur 37 soit 24%). Ajoutée à ce fait fut l'élévation de la VIP chez 3 sujets (8%), de la motiline chez 5 (13.5%) et de la substance P chez 3 (8%). Les phéochromocytomes bénins surrénaliens présentaient à la fois une élévation du taux de la SS et de la substance P. Les phéochromocytomes ectopiques en revanche présentaient seulement une élévation de la SS. Les phéochromocytomes malins pouvaient sécréter les 4 peptides ou plus d'un chez le même malade. En conclusion les phéochromocytomes peuvent secréter de multiples peptides vasoactifs et plus particulièrement lorsqu'ils sont malins. La SS est la substance qui est la plus souvent secrétée et elle est trouvée dans les tumeurs bénignes surrénaliennes ou ectopiques. Si plus d'une de ces substances est produite en excès les risques de malignité de la tumeur sont significativement plus importants. Los feocromocitomas generalmente son diagnosticados por los efectos del exceso de producción de catecolaminas pero hay características clínicas que no pueden ser atribuidas al exceso de catecolaminas y que pueden ser más bien manifestación de péptidos vasoactivos. Hemos establecido los niveles sanguíneos del péptido intestinal vasoactivo (VIP), de la sustancia P, de la somatostatina (SS), y de la motilina en 50 determinaciones en 37 pacientes con feocromocitomas; 21 malignos, 10 benignos intra-adrenales, y 6 ectópicos (5 paracardiales y 1 perirrenal). Se consideró que los niveles hormonales estaban elevados cuando el nivel era de más de 3 de desviación estandar sobre el valor promedio en 52 individuos normales. De 37 pacientes, 20 (54%) presentaron un valor anormal en 1 o más determinaciones del nivel de hormonas intestinales. La anormalidad más común fue la elevación de la SS en 9/37 (24%). Además de esto, sinembargo, otros 3 (8%) presentaban elevación de VIP, 5 (13.5%) elevación de sustancia P. Los adenomas suprarrenales benignos exhibieron niveles elevados de SS y de sustancia P. Los feocromocitomas ectópicos demostraron producción sólo de SS además de catecolaminas, pero los feocromocitomas malignos demostraron ser capaces de secretar todos los 4 péptidos, y más de 1 en el mismo paciente. Hemos llegado a la conclusión de que los feocromocitomas pueden secretar múltiples peptidos vasoactivos y que ésto tiende a ocurrir cuando son malignos. La SS es el péptido más frecuentemente secretado y se lo encuentra en los tumores suprarrenales benigno y ectópico (paracardiacos). Si se encuentran niveles elevados de más de 1 péptido, la posibilidad de malignidad aparece significativamente aumentada.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41274/1/268_2005_Article_BF01655534.pd