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Biomedical subjects

P Sandblom

Publications and source records attributed to P Sandblom.

At least 19 recordsLinked to original sources
PubMed1987

Biliary calculi caused by hemobilia.

Formation of biliary calculi caused by hemobilia is rare. Including the two cases reported here, there are only a total of four in the literature. The characteristics of these calculi in vitro, on computerized tomographic scan, and cholecystography are described. The condition for the occurrence seems to be that blood clots remain in the gallbladder sufficiently long (about 6 months) to become encrusted with bile constituents. Patients with hemobilia with clots in the gallbladder should be observed for this complication.

Adolescent↗
PubMed1986

Molecular dynamics simulations of the holo and apo forms of retinol binding protein. Structural and dynamical changes induced by retinol removal.

The effects of removing retinol from the X-ray structure of holo-retinol binding protein are studied using the molecular dynamics technique. Structural and dynamical properties emerging from an 80 ps simulation of the apo form, for which no crystallographic structure is available, are compared with the results of a 70 ps trajectory of the holo-protein. Dynamical stationarity is attained after roughly 30 ps, and the resulting average structure is proposed as a reasonable model of the apo-protein. Conformational changes are observed for the loops at the beta-barrel entrance during the non-equilibrium part of the apo-trajectory. Tryptophan labelling experiments and retinoid reconstitution experiments point towards this part of the molecule as being involved in prealbumin binding. Structural changes in this region may therefore explain the differences in prealbumin affinity between the apo and holo forms. Furthermore, a change in the position of the alpha-helix, corresponding to a pivot around its C terminus, is observed for the apo-protein. The resulting conformation of the alpha-helix is found to be similar to that in apo-beta-lactoglobulin, which also can bind retinol and for which a crystal structure exists. The results from the holo simulation are compared to the crystallographic data and show good agreement. The dynamics of the secondary and tertiary structural elements are analysed and compared for the two forms. The beta-barrel is found to be extremely cooperative in its atomic motions in both simulations, and the top and bottom beta-sheets perform collective fluctuations with respect to each other in the low-frequency limit of the simulations. The dynamics of the alpha-helical region presents clear differences between the two forms; while the holo-protein has a well-defined spectrum for the longitudinal stretching mode, the apo form displays a fairly large bending of the alpha-helix at several points of the trajectory.

Computer Simulation↗
PubMed1986

Structural changes in retinol binding protein induced by retinol removal. A molecular dynamics study.

Relationships between structure and function for retinol binding protein (RBP) are elucidated with help of a 2.0 A resolution X-ray structure of the holo-protein and an average molecular dynamics (MD) structure of the apo-form. Comparisons between MD simulations of both the apo- and holo-forms with the X-ray holo-structure show conformational changes in apo-RBP that may be functionally significant. The average three dimensional structure obtained for apo-RBP is compared to the related protein apo-beta-lactoglobulin. Available biochemical information is consistent with structure/function relationships derived here.

Humans↗
PubMed1986

Iatrogenic hemobilia.

Biliary tract hemorrhage is increasingly reported as a complication of diagnostic and therapeutic interventions on the liver and the bile ducts. Major hemobilia with profuse, even life-threatening, hemorrhage which necessitates emergency surgical intervention is uncommon. Minor hemobilia with melena or clot production in the ducts, although more common, may cause diagnostic difficulties. Diagnosis is obtained either endoscopically to demonstrate bleeding through the papilla of Vater, or through hepatic arteriography, which has the advantage of indicating the location of the lesion. Operative treatment with resection of the lesion or ligature of the hepatic artery or a branch has been replaced by embolization of the affected artery. Diagnostic procedures that may cause hemobilia include percutaneous needle biopsy and transhepatic cholangiography. The risk of hemorrhage increases if a catheter is left in place for drainage. Difficult extractions of common duct stones may cause hemorrhage due to lesions of the vulnerable duct mucosa. Finally, spontaneous hemobilia may, like hematuria or epistaxis, be caused by an overdose of anticoagulants.

Anticoagulants↗
PubMed1985

Ailing artists.

Explore the source record for details and available documents.

Medicine in Literature↗
PubMed1979

Minor hemobilia. Clinical significance and pathophysiological background.

Profuse hemorrhage into the biliary tract--major hemobilia,--is an alarming condition which attracts much attention. Minor hemobilia, often caused by gallstones or operative injury, is much more frequent, yet often neglected. Clinical observations indicate that minor hemobilia is not always an innocent condition with the blood remaining fluid and unobtrusively flowing into the intestine. Examples are given where clots from occult hemobilia have caused diagnostic errors or obstructed the bile flow, thus imitating gallstones for which they may be mistaken. Experiments have been performed to elucidate the pathophysiology of this clot formation: 1) A model of the biliary tract was constructed with bile flowing through it. When blood was injected forcefully to simulate a major hemorrhage, mixed clots of blood and bile were formed. When introduced gently, as in minor hemobilia, the blood flowed immiscibly to the lowest level where it formed a clot of pure blood. The clots dissolved under the influence of flowing bile, but remained intact when protected from the flow. 2) Mixed clots were mushy and dissolved spontaneously, while pure clots remained solid and stable. When clots containing increasing amounts of bile were incubated, increasing amounts of cleavage products of fibrinogen and fibrin were formed. 3) Blood clots were produced in gallbladders of 33 dogs. Pure clots remained solid and floating while mixed clots formed a mushy layer, strongly adherent to the mucosa. Both kinds of clots disappeared after two-four weeks, but remained if bile flow was diverted. These findings explain why under certain circumstances minor hemobilia acquires clinical significance by forming clots that may obstruct the flow or cause diagnostic errors. Successful dissolution of "retained stones" may occasionally have the simple explanation that blood clots, mistaken for calculi, have been fibrinolysed. Consequently, in biliary obstruction or when defects are found on cholangiography, the possibility of blood clots in the ducts should be considered even in the absence of overt gastrointestinal hemorrhage.

Adult↗
PubMed1977

Formation and fate of fibrin clots in the biliary tract: a clinical and experimental study.

Fibrin clots may form in the biliary tract from hemobilia or in inflammatory disease. There is a wide variation in the clinical course of such clots which is exemplified by 9 patients. They may either dissolve through fibrinolysis, get ejected into the intestine, remain and obstruct the biliary tract, or may even transform into gallstones. In order to elucidate the mechanisms involved, the behavior of blood clots in bile was studied in vitro. A model was constructed of the biliary tract and, drained by a T-tube, where human bile circulated with a flow rate resembling that in vivo. When a small amount of human blood was injected, it flowed immiscibly to the lowest level, displaced the bile, and formed a clot of pure blood. Even a minor bleeding may thus form a coagulum. This is different from the mixed clot of blood and bile that forms in experiments simulating major hemorrhage. These findings are related to clinical experience and especially to the disappearance of "retained stones" with or without the use of dissolving agents.

Biliary Tract↗
PubMed1976

The healing of liver wounds.

Cases of traumatic hemobilia are often characterized by a protracted history with recurrent episodes of hemorrhage over many years. It seems that while the liver regenerates quickly and profusely it heals slowly and poorly. This is in contradistinction to the kidneys where lesions often heal within a short time. In order to investigate the cause of this peculiar behavior a series of experiments was performed where local lesions were produced in the musculature, in the kidneys and in the liver of dogs. The healing process was studied at different intervals. There was essentially no difference between the rate and character of healing in the three localities. As the lesions that produce hemobilia are open to the biliary tract, another series of experiments was performed where the healing took place in presence of bile. The effect of this was striking with a very diminished production of fibrinous exudate, granulating tissue and fibrous scar.

Animals↗
PubMed1975

Wound healing in man: tensile strength of healing wounds in some patient groups.

The healing of test wounds was studied in 108 patients, in whom some impairment of wound healing was suspected. A 5 cm skin wound was performed in the forearm and the strength of the wound was tested after 5 days using the technique described by Sandblom and associates with two measurements in each wound. No differences in wound strength could be registered between the two wounds in each patient, between males and females nor in patients with malignant disease compared to other patients. Patients with low serum protein or serum albumin values had significantly weaker wounds than patients with normal protein values. Patients over 80 years of age had wounds somewhat weaker than those below 70, the difference having a statistical significance of 6%. The wound strength in patients was compared to values found elsewhere for wounds in rabbits, rats, and piglets. The pigs had much higher values than others, rabbits slightly stronger than and rats about equal to humans.

Age Factors↗
PubMed1975

[Hemobilia. (Apropos of 5 cases)].

Hemobilia or hemorrhage through the biliary tract is increasing in frequency. With spreading knowledge of the syndrome, the diagnosis is now rarely missed. There is also a real increase due to traffic accidents which often cause liver injuries. The typical triade with digestive hemorrhage, biliary colic and jaundice should always arouse suspicion of hemobilia. Hepatic angiography is the best and most accurate diagnostic method. Accidental or operative trauma constitute the major cause of macroscopic hemobilia where as microscopic hemobilia is a very frequent symptom in gallstone-disease. In this report five cases of different ethiology are described. Three were caused by abdominal trauma. The fourth case illustrates the risk of hemobilia from instrumental exploration of the common duct. Even when this is done carefully it might cause a hemorrhage with formation of obstructing clots. In the last patient there was severe hemobilia due to errosion of the cystic artery by a gallstone, penetrating into the duodenum. The treatment given in the five cases are examples of different methods which may be used, according to the nature of the lesion. In the three cases of traumatic hemobilia one healed spontaneously under angiographic control, one was cured by local hemostasis in the central liver rupture and the third had a successful hepatic resection. In the case with post-operative hemobilia, an obstructing clot had to be removed from the common duct. Simple cholecystectomy cured the patient with hemorrhage from the eroded cystic artery.

Aged↗
PubMed1975

Repair of common bile duct defects using the gallbladder or cystic duct as a pedicled graft.

To repair defects in the common bile duct, part of the gallbladder and the cystic duct may be used as a pedicled graft. This has the advantage of an independent blood supply and a related mucosal lining. The method is illustrated by four patients who had excellent primary and short term results. In two patients, the defect was due to large cholecystocholedochal fistulas caused by migrating large gallstones. In one patient with marked stenosis of the duct, the defect occurred when the stenosis was opened through a longitudinal incision. The fourth patient had a large duodenal ulcer that penetrated into the common duct, causing a defect that could not be closed by suture. A definite evaluation of the procedure must await a longer period of follow-up study.

Adult↗