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Biomedical subjects

I Lorén

Publications and source records attributed to I Lorén.

At least 19 recordsLinked to original sources
PubMed2001

Transrectal catheter drainage of deep abdominal and pelvic abscesses using combined ultrasonography and fluoroscopy.

OBJECTIVE: To describe our experience with transrectal drainage of deep abdominal or pelvic abscesses guided by ultrasonography and fluoroscopy. DESIGN: Open study. SETTING: Teaching hospital, Sweden. SUBJECTS: Eight seriously ill patients with deep abdominal or pelvic abscesses. INTERVENTION: Ultrasonographic and fluoroscopic transrectal drainage. MAIN OUTCOME MEASURES: Clinical follow-up. RESULTS: Eight patients (2 septic, 2 with high fever, and 2 with moderate fever) were effectively and safely drained without general anaesthesia. Their condition improved considerably within hours after drainage. Three patients had recurrent abscesses as a result of the underlying disease. The drainage overcame the sepsis in two patients and allowed a later elective operation. CONCLUSIONS: Transrectal ultrasonographic and fluoroscopic drainage is an effective and safe method for treatment of deep abdominal or pelvic abscesses in seriously ill patients.

Abdominal Abscess↗
PubMed1999

New sonographic imaging observations in focal pancreatitis.

The imaging findings that ultrasonographically differentiate focal acute pancreatitis (FAP) from a malignant lesion of the pancreas are described. Focal acute pancreatitis is ultrasonographically (US) characterized as a hypoechoic, homogeneous, localized, subsegmental, non-expansive and diffusely demarcated lesion located mostly in the head of the pancreas. It could not be visualized using CT. Endoscopic retrograde cholangiopancreatography (ERCP) performed in 13 of the 32 patients, showed chronic pancreatitis. Focal acute pancreatitis disappeared in 1-6 months at US follow-up. The clinical diagnoses were acute pancreatitis in 11 patients, chronic pancreatitis in 12 patients, biliary disease in 5 patients, hepatopathia in 1 patient while the diagnosis was unknown in 2 patients. No patient developed any pancreatic cancer during a median of 85 months of follow-up. In conclusion, the present data indicate that patients with FAP at US, without any focal lesion seen on either CT or ERCP, have a benign pancreatic lesion, which resolves in 1-6 months; thus, such patients probably do not need any further investigation or follow-up at all.

Acute Disease↗
PubMed1999

Power Doppler ultrasonography: alternative to computed tomography in abdominal trauma patients.

The aim of this study was to determine if power Doppler ultrasonography, contrast enhanced when necessary, can be used as an alternative to computed tomography in the diagnosis of trauma-related organ rupture or hematoma. Fifteen patients who had sustained abdominal trauma but who had normal results on B-mode scans were included in the study. Twenty organs (13 livers and 7 spleens) were examined with both contrast-enhanced computed tomography and power Doppler ultrasonography in a blinded fashion. Ultrasonographic contrast was used in five patients. Lack of contrast enhancement (computed tomography) or lack of color in power color Doppler ultrasonography in all or part of the organ was taken as a sign of rupture or hematoma. Five ruptures were detected with both modalities (two hepatic and three splenic). Thus, ultrasonography showed no false-positive or false-negative studies when compared to the computed tomographic results. No significant difference was found in the estimated size of the damaged area between the two types of investigation. The study indicates that power color Doppler ultrasonography may be considered an alternative when a computed tomographic scan of a trauma patient is impossible.

Abdomen↗
PubMed1998

Colour Doppler imaging of shunts from the left portal branch in portal hypertension. Description of a typical pattern.

PURPOSE: To describe the typical colour Doppler appearance of a shunt through the parenchyma of the left lobe of the liver in portal hypertension. MATERIAL AND METHODS: Ultrasound images of 141 patients with biopsy-verified cirrhosis were reviewed. Special note was taken of the appearance of shunts from the left portal branch. RESULTS: In 28 patients, shunts from the left portal branch were detected ultrasonographically, 10 of which ran through the liver parenchyma on a course separated from the ligamentum teres. Seven of these 10 followed a tortuous course just below the surface of the liver creating a ball or corkscrew-like pattern. CONCLUSION: Shunts from the left portal branch are not uncommon and may represent the only ultrasonographically detectable pathology in these patients. Recognition of the typical pattern will facilitate their detection.

Biopsy↗
PubMed1998

Color Doppler energy: detection of hypoperfused areas in renal transplants.

The aim of this study was to determine if an area of decreased color on color Doppler energy scans in a transplanted kidney could be related to significant pathologic conditions. Three hundred and ninety-eight scans in 150 patients were thus evaluated prospectively, and 12 such areas were found and correlated to B-mode, spectral, and color Doppler sonography as well as clinical and laboratory findings. A cause for the hypoperfused area was found in all cases; causes included two cases of focal infection, four arteriovenous fistulas, one kinking of an artery, and five perioperatively severed accessory arteries. We conclude that a color Doppler energy evaluation of perfusion differences can be used to detect pathologic lesions in a transplanted kidney.

Humans↗
PubMed1997

Color Doppler energy: computer analysis for detection of volume flow variations.

The aims of this study were to (1) determine whether analysis of a color Doppler energy image can show small differences in volume flow and (2) determine the performance characteristics of color Doppler energy to aid future analyses. Flow through a silicone tube in a waterbath was insonated, and the images were analyzed by computer producing arbitrary values for the different flow volumes at different machine settings. A significant difference in the derived values was found at volume low changes of 10 ml/min. The differences are most pronounced when small amounts of color are shown in the vessel. This region of high sensitivity can be altered by changing the machine settings of filter, scale, or level. The angle of insonation must be taken into account. In conclusion, computer analysis of color Doppler energy can monitor changes in blood flow volume with a high sensitivity.

Image Processing, Computer-Assisted↗
PubMed1997

Color Doppler energy: computer analysis of color to assess angle dependency and detection of volume flow differences.

The aims of this study were to assess (1) any angle dependency of color Doppler energy and (2) if computer analysis of the color can distinguish variations in volume flow. Fluid flowing through a silicon tube in a waterbath was insonated and the color in the images analyzed by a computer. The color presentation on the screen decreases rapidly as the angle approaches 90 degrees. At angles that did not produce a saturation of the color in the tube, the computer analysis detected significant differences between different flow volumes. We have concluded that monitoring of volume flow changes by analysis of color Doppler energy is possible, but the angle of insonation must be taken into account.

Image Enhancement↗
PubMed1996

Bilateral isolated adrenal coccidioidomycosis.

A case of bilateral isolated adrenal coccidioidomycosis in a previously healthy and immunocompetent 43-year-old Caucasian male is presented. He had never travelled to a coccidioidomycosis endemic area. Subclinical adrenal dysfunction was found with elevated plasma ACTH and mineralocorticosteroid and androgen pathway abnormalities. The implement of the fungal infection on adrenal function, and the diagnosis and management of adrenal coccidioidomycosis are discussed.

Adrenal Gland Diseases↗
PubMed1995

Ultrasonography in gallstone ileus: a diagnostic challenge.

OBJECTIVE: To describe our experience with ultrasound diagnosis of gallstone ileus in six cases, and to assess the impact of our findings in the light of published reports. DESIGN: Open study. SETTING: Teaching hospital, Sweden. SUBJECTS: Six patients with gallstone ileus. INTERVENTION: Abdominal ultrasound examination. MAIN OUTCOME MEASURES--Correlation with plain abdominal films and with findings at laarotomy. RESULTS: In all six cases ultrasound gave a precise diagnosis of gallstone ileus, together with the exact location of the gallstone, whereas plain films usually indicated only intestinal obstruction of unknown cause. There was not mortality and only one postoperative complication, and all patients were alive and well at the time they were last seen. These results compare well with those of other reported series. CONCLUSION: The high morbidity and mortality of gallstone ileus may be reduced if ultrasonography is used in cases of undiagnosed abdominal pain, particularly in elderly patients with protracted symptoms.

Aged↗
PubMed1982

Substance P-immunoreactive nerve fibres in the anterior segment of the rabbit eye. Distribution and possible physiological significance.

Substance P-immunoreactive nerve terminals were found in several locations in the anterior segment of the rabbit eye. In the iris they occurred in the sphincter muscle and were randomly distributed in the iris stroma with some fibres running close to the dilator muscle. In the ciliary body these immunoreactive elements were few and occurred within bundles of nerve fibres. while in the ciliary processes they were more numerous with a predominantly subepithelial location. Blood vessels in the anterior uvea were often surrounded by substance P-immunoreactive fibres. No substance P-fibres were found in the cornea, while the sclera contained very few such elements. Using conventional in vitro techniques it was found that the sphincter pupillae muscle of the iris responded to electrical stimulation with a contraction that was resistant to cholinergic and adrenergic blockade, but was inhibited by the neuronal blocker tetrodotoxin. This indicates the existence of a non-cholinergic, non-adrenergic neuronal mediator of the contractile response. Exogenously applied substance P produced a long-lasting contraction of the spincter muscle, an observation compatible with the view that substance P is the noncholinergic, non-adrenergic neurotransmitter involved.

Animals↗
PubMed1982

Prefrontal cortex: dense dopaminergic input in the newborn rat.

Using a recently introduced modification of the aluminum-formaldehyde histofluorescence method, in combination with exogeneous administration of alpha-methylnoradrenaline and biochemical analyses, a remarkably advanced development of the dopaminergic and noradrenergic afferent to the frontal lobe has been demonstrated in neonatal rat. At birth, the density and general distributional pattern of the catecholamine innervation was similar to that found in the fully developed prefrontal cortex. The previously not recognized, early and extensive maturation of the mesocortical dopamine projection suggests a functional role of dopamine already in the early postnatal period.

Aging↗
PubMed1981

Adrenergic innervation of pancreatic islets and modulation of insulin secretion by the sympatho-adrenal system.

Morphological changes in the adrenergic innervation of pancreatic islets after chemical sympathectomy by use of 6-hydroxydopamine and the influence of the sympatho-adrenal system on insulin secretion were investigated in the mouse and rat. Fluorescence histochemistry revealed a clear-cut reduction in the number of adrenergic nerve fibres in the pancreatic islets 2 days after administration of 6-hydroxydopamine; the reduction was more pronounced in the rat than in the mouse. In the rat, a partial regeneration was seen after 6 weeks. In the pancreas of the mouse, after administration of 6-hydroxydopamine, a severe damage of unmyelinated nerve fibres was revealed electron microscopically. However, no ultrastructural or immunohistochemical alterations could be demonstrated in the endocrine cells of the islets. 6-Hydroxydopamine induced a depression of basal plasma insulin concentrations in mice and an elevation in rats. Adrenalectomy depressed basal plasma insulin levels in mice. The alpha-adrenoceptor antagonist phentolamine enhanced insulin secretion in normal mice. The secretory response of insulin to phentolamine was diminished by chemical sympathectomy and almost abolished by adrenalectomy or the combination of chemical sympathectomy and adrenalectomy. Thus, the effect of phentolamine is probably mediated by liberated catecholamines. It is concluded that basal insulin secretion is partially regulated by the sympatho-adrenal system and that species differences exist in this respect. In addition, the results suggest that endogenous catecholamines have the ability to promote insulin secretion.

Adrenal Cortex↗
PubMed1981

Recent developments in aldehyde-induced monoamine fluorescence: the aluminum-formaldehyde (ALFA) method applied to immature and adult central nervous tissue.

In this review, the new aluminum-formaldehyde (ALFA) histofluorescence method for the highly sensitive visualization of monoamine-containing neurones in adult and immature central nervous tissue is summarized. Animals are first perfused with a buffer containing high concentrations of aluminum ions and the brains are then freeze-dried, reacted with formaldehyde vapour and further processed according to the Falck-Hillarp fluorescence method. The ALFA technique applied to adult brains visualizes all known catecholamine neurone systems with a sensitivity comparable to, and for certain noradrenergic systems higher than, that of the previously published glyoxylic acid-Vibratome method. The catecholamine systems in immature brains are demonstrated with a sensitivity clearly superior to that of any other available method. If the ALFA method is combined with systemic injections of alpha-methylnoradrenaline into young animals (less than one week old), there is a dramatic increase in the intensity and number of catecholaminergic fibres. Many catecholaminergic systems which have too low concentrations of transmitter to be visualized in the untreated animal even with the ALFA method, can be demonstrated after administration of alpha-methylnoradrenaline. The use of freeze-dried, paraffin-embedded tissue in the ALFA method makes possible convenient storage and parallel processing of many specimens. This mode of processing also allows en bloc reaction, which is the only way by which consistent and reproducible fluorescence yields can be obtained throughout large series of sections and parallel-processed specimens. In animals pretreated with L-tryptophan and monoamine oxidase-inhibitor, the technique is also useful for studies on central indolamine-containing systems.

Age Factors↗
PubMed1980

VIP occurs in intrathyroidal nerves and stimulates thyroid hormone secretion.

Vasoactive intestinal polypeptide (VIP) is known to have powerful effects on the secretion from several endocrine and exocrine glands, and occurs in nerves with a ubiquitous distribution in the body. This infers that neuronal VIP may be a regulator of such secretion, and there is evidence that it is involved in the regulation of exocrine pancreatic function. Previous studies have shown that adrenergic and cholinergic nerves participate in the regulation of thyroid hormone secretion. We describe here combined immunohistochemical and immunochemical studies which show that the thyroid of several species is supplied with VIP-containing nerve fibres that surround blood vessels and run between and along thyroid follicles and that in the mouse neuronal VIP participates in the regulation of thyroid hormone secretion through a mechanism that is mediated by cyclic AMP.

Animals↗
PubMed1980

Vasoactive intestinal peptide (VIP) occurs in nerves of the pineal gland.

Nerves staining with antibodies against vasoactive intestinal peptide (VIP) were detected in the pineal gland of the rabbit, cat and pig. VIP nerves were numerous in the cat but few in the rabbit and pig. A particularly rich VIP nerve supply was noted in the pineal stalk of the cat. The nerves were predominantly located around small blood vessels. Occasionally, nerve fibres were seen in the glandular parenchyma without obvious relation to blood vessels.

Animals↗