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Biomedical subjects

D Kelemen

Publications and source records attributed to D Kelemen.

14 recordsLinked to original sources
PubMed2002

Clinical experience with different techniques of pancreatic head resection for chronic pancreatitis.

BACKGROUND/AIMS: Recently organ-saving procedures have become popular in the treatment of chronic pancreatitis with head enlargement. The purpose of this study is to compare the results of three different procedures. METHODS: Between 1991 and 1998, 32 Beger operations, 13 Frey procedures and 21 pylorus-preserving pancreatoduodenectomies (PPPDs) were performed. The pre-, intra- and postoperative data were detailed. During the follow-up examination the quality of life, body weight, consumption of alcohol and enzymes, as well as the carbohydrate metabolism were checked. RESULTS: Considering the operative and late mortality and reoperation rate, there was no difference between the procedures. The postoperative hospitalization time was the shortest after the duodenum-preserving pancreatic head resections (Beger and Frey). While the rate of early morbidity was higher after PPPDs, there was no difference in late morbidity between the groups. The condition of the patients was better and the development rate of diabetes was lower after the Beger procedure than after PPPDs. CONCLUSION: Consequently duodenum-preserving pancreatic head resections seem to be more advantageous than PPPD. Nevertheless the latter operation is the only possibility in some situations.

Adult↗
PubMed1999

[Comparative study of pancreatic head resection in chronic pancreatitis].

Between 1991 and 1998 the authors performed 21 pylorus-preserving pancreatoduodenectomies (PPPD), 32 Beger and 13 Frey procedures in chronic pancreatitis with inflammatory head enlargement. The pre- and intraoperative data, as well as the postoperative early and late results were also compared. The preoperative clinical features and the intraoperative morphology were similar in the three groups. Considering the operative and late mortality and the reoperation there was no statistical difference between the procedures. The postoperative hospitalization time was the shortest after the duodenum-preserving pancreatic head resections (Beger and Frey). While the rate of early complications was significantly higher after PPPD, there was no difference in the rate of late complications between the groups. Although each operation gave similarly good late results (freedom from pain, weight gain, exocrine function, quality of life), the condition of the patients was better and the development rate of diabetes was lower (1/27), after Beger procedure, that after PPPD (6/14). Consequently the duodenum-preserving pancreatic head resections seem to be more advantageous, than the PPPD. Nevertheless the latter procedure is the only possibility in some cases.

Chronic Disease↗
PubMed1999

The scope of teleological thinking in preschool children.

These studies explore the scope of young children's teleological tendency to view entities as 'designed for purposes'. One view ('Selective Teleology') argues that teleology is an innate, basic mode of thinking that, throughout development, is selectively applied by children and adults to artifacts and biological properties. An alternative proposal ('Promiscuous Teleology') argues that teleological reasoning derives from children's knowledge of intentionality and is not restricted to any particular category of phenomena until later in development. Two studies explored the predictions of these two hypotheses regarding the scope of children's functional intuitions. Using different methods, both studies found that, unlike adults, pre-schoolers tend to attribute functions to all kinds of objects--clocks, tigers, clouds and their parts. A third study then explored this finding further by examining whether the developmental effect was due to differences in children's and adults' concept of function. It found that both children and adults predominantly view an object's function as the activity it was designed to perform. Possible explanations for the developmental differences found in the first two studies, and implications for notions of a teleological stance are discussed.

Adult↗
PubMed1999

Function, goals and intention: children's teleological reasoning about objects.

A fundamental aspect of adult thought is the 'teleological' tendency to assume that objects exist for a purpose. When seeing an unfamiliar artifact or strange anatomical part on an animal, the first question an adult will usually ask is 'what's that for?' - a query that assumes that the object can be teleologically explained in terms of its function. Current debate focuses on the origin and scope of teleological thought, and its role in children's emerging theories of the biological world. The bias to view objects as 'designed for a purpose' probably derives from children's privileged understanding of intentional behavior and artifacts. This makes children prone to a 'promiscuous teleology' in which artifacts and natural objects of all types are viewed as existing for a function. Because of this, I argue that we should be cautious about taking the existence of an early teleological bias as evidence that there is biological understanding that exists independently of a psychological construal of living things.

Journal Article↗
PubMed1999

Why are rocks pointy? Children's preference for teleological explanations of the natural world.

Teleological explanations are based on the assumption that an object or behavior exists for a purpose. Two studies explored the tendency of adults and first-, second-, and fourth-grade elementary-school children to explain the properties of living and nonliving natural kinds in teleological terms. Consistent with the hypothesis that young children possess a promiscuous teleological tendency, Study 1 found that children were more likely than adults to broadly explain the properties of both living and nonliving natural kinds in teleological terms, although the kinds of functions that they endorsed varied with age. Study 2 was an attempt to reduce children's broad teleological bias by introducing a pretrial that described, in nonteleological terms, the physical process by which nonliving natural kinds form. In spite of this attempt, Study 2 replicated the effects of Study 1, with only fourth graders showing any shift in preference for teleological explanation.

Adult↗
PubMed1995

Syntactic cues in the acquisition of collective nouns.

One basic finding in the study of word learning is that children tend to construe a word describing an object as referring to the kind of whole object, rather than to a part of the object, one of its properties, or the substance it is made of. This has been taken as evidence that there exist certain special constraints on word meaning that guide children to favor the kind-of-object interpretation when exposed to a new word. There are descriptive problems with this proposal, however, as it cannot explain how children learn other kinds of words, such as names for specific people, substances, parts, events, collections, and periods of time. These problems motivate an alternative theory in which young children possess several distinct conceptual categories--including "individual", which is more abstract than "whole object"--and can use syntactic cues to determine the conceptual category that a new word belongs to. This theory is explored in two experiments in which we attempt to use syntactic cues to teach children and adults novel collective nouns--words that refer to groups of objects. The results indicate that children can use such cues to learn names for kinds of individuals that are not whole objects, although they are less able to do so than adults. Candidate explanations for why this developmental difference exists are discussed and implications are drawn for theories of word learning and conceptual representation.

Adult↗
PubMed1992

A new computerized polarization--microscopic method for the demonstration of collagen fibers.

A new computerized polarization microscopic method was developed for objective, quick quantitative analysis of anisotropic structures. The paper presents the technology on collagen fibers of kidney and liver preparations. According to the observations the birefringence of one fiber can be characterized not by a single number as it is accepted generally but by a series of data. It suggests that the process of compensation is gradual. One of the explanations of this fact might be that the collagen fibers are inhomogeneous at submicroscopic level. With regard to this assumption, first several birefringent capillary basement membranes of a whole glomerulum were measured simultaneously. In this case, the individual capillaries showed nearly the same retardation. Second, portal zones of normal and cirrhotic livers as functional units were analyzed simultaneously. In the latter case the individual fibers show different birefringence. Comparing the results obtained by their technique with the data of the classic measuring method authors found similarity that proved its validity. Data suggest that the new method seems to be useful in experimental and diagnostic pathology.

Birefringence↗
PubMed1990

Pancreatogastrostomy in experimental acute necrotizing pancreatitis.

Experimental acute necrotizing pancreatitis was induced retrogradely in dogs with sunflower oil injected intraductally. Then, a zipper was sutured into the abdominal wound. From the first postoperative day, three different treatments were started: first group: only conservative therapy was used; second group: removal of necrotized tissue and single peritoneal lavage were applied; and third group: the necrotic part of the pancreas was marsupialized into the stomach. Through the systematic opening of the zipper, the abdominal cavity could easily be explored and the temporal course of disease could be observed in all animals. During this regular procedure, the amylase concentration and the amount of peritoneal exudate were determined. The blood amylase and glucose levels were also measured. On the first postoperative day, the amylase level and the amount of peritoneal exudate were high in all groups. The dogs of the pancreatogastrostomized group showed a dramatic decrease of the exudate and the most advantageous temporal course of the blood amylase level. The survival rate similarly was advantageous in the pancreatogastrostomized group.

Acute Disease↗
PubMed1990

Influence of protective drugs on the elevation of extracellular potassium ion concentration in the brain during ischaemia.

Influence of drugs on the changes of extracellular potassium ion concentration in the brain during total cerebral ischaemia was investigated. The aorta of the dogs was clamped twice with an intermittent reperfusion period of 60 min. In control experiments no significant difference was found in the elevation of extracellular potassium ion concentration of the brain during the first and second clampings. In the present study drugs were administered 10 min prior the second aorta occlusion. Verapamil in a dose of 0.125 mg/kg proved to be ineffective. Piridoxilate in a dose of 10 mg/kg and piracetam in a dose of 100 mg/kg delayed to a small extent the potassium outflow. The following drugs enhanced significantly the duration before the steep increase of potassium ion outflow: phenytoin in a dose of 10 mg/kg by 31.8 sec (p less than 0.01), ethyl-butyl-thiobarbital in a dose of 15 mg/kg by 30.2 sec (p less than 0.05), and lidocaine in a dose of 100 mg/kg by 115.8 sec (p less than 0.01). Comparing present results to our earlier data (obtained after 50 sec ischaemia) it can be concluded, that these protective influences become more effective during longer ischaemic period (2-5 min), when lidocaine, phenytoin and ethyl-butyl-thiobarbital were used. Moreover, in spite of the observation seen during shorter ischaemia, even piridoxilate and piracetam exerted some degree of protective effect. No such effect of verapamil could be detected in the present experimental model.

Animals↗
PubMed1990

Oxygen-derived free radical reactions in experimental acute pancreatitis of the dog.

Acute edematous and necrotic pancreatitis have been induced in dogs with retrogradely intraductal injections of 5% hydrogen peroxide solution and sunflower-oil. The process of disease could be followed daily by a zipper sutured into the abdominal wound. In this manner the temporal changes of markers of oxygen-derived free radicals (concentrations of malondialdehyde and reduced glutathione of the excised pancreas tissue and abdominal exudate, as well as the superoxide dismutase content of the tissue) could be controlled. Light microscopic analysis was also done. In edematous pancreatitis reversible membrane lesions, in the necrotic form the irreversible damage of membranes and cells could be seen. The results obtained suggest the role of oxygen-derived free radicals in experimental acute pancreatitis.

Acute Disease↗
PubMedDate not supplied

Free radical mediated injuries after coronary artery occlusion.

The left descending coronary artery (LAD) of mongrel dogs was ligated for one month to evaluate the effect of a dihydroquinoline-type antioxidant (MTDQ-DA) during the healing process of myocardial infarction. Thirty animals were divided into three groups: I) control animals (10 dogs) were treated with saline infusion during operation and postoperative days; II) 10 dogs were treated with intravenous MTDQ-DA during the operation followed by postoperative oral treatment, and III) 10 animals were treated with preoperative and postoperative oral treatment plus intraoperative MTDQ-DA infusion. The antioxidant effects were evaluated by measurements of the lipid peroxidation and product malondialdehyde (MDA) and of endogenous scavengers: reduced glutathione (GSH) and superoxide dismutase (SOD) in the ischemic and in intact areas. Ultrathin sections were investigated by JEOL 100 C electron microscope. Elevation of lipid peroxidation (LPO) was present in each group. The most remarkable changes were seen in the control ischemic areas (152 +/- 6.7%). GSH was depleted in the infarcted areas of the control hearts (60 +/- 5.6%), in the antioxidant treated animals this thiol compound was only slightly decreased (81 +/- 5.6%). SOD activity showed a sharp decline (group I) in both ischemic (52 +/- 8.3 U/g) and non-ischemic parts of the left ventricle (78 +/- 7 U/g). After MTDQ-DA treatment (groups II, III) SOD activity diminished only in the ischemic area (83 +/- 8.5 U/g); other parts showed normal (123 +/- 7.2 U/g) activity. According to ultrastructural examinations, MTDQ-DA diminished the degree of structural injury.

Animals↗
PubMedDate not supplied

Home testing of fructosamine improves glycemic control in patients with diabetes.

OBJECTIVE: To determine whether weekly fructosamine testing at home by patients with type 2 diabetes, combined with therapeutic intervention when necessary on the basis of the results, would lead to improved glycemic control in comparison with usual care during a 3-month period. METHODS: In a prospective study, 25 patients with glycosylated hemoglobin (HbA1c) values above 8.0% were randomized into 2 groups. Both groups, a glucose-only testing group (14 patients with an initial mean HbA1c of 9.4 +/- 0.9%) and a combined glucose plus fructosamine testing group (11 patients with an initial mean HbA1c of 9.2 +/- 0.7%), received therapeutic intervention at the time of randomization. Both groups were instructed to perform blood glucose testing up to four times per day. The combined glucose plus fructosamine testing group was also instructed to perform weekly fructosamine testing in addition to the glucose testing and to telephone the investigator if their home-testing fructosamine value exceeded 350 mmol/L (approximately equivalent to HbA1c of 7.8%), whereupon the investigator implemented further interventions. Both groups returned in 3 months, at which time HbA1c testing was repeated in order to determine whether glycemic control had changed. RESULTS: The study results after 3 months showed that the HbA1c values in the combined glucose plus fructosamine testing group decreased from 9.2 +/- 0.7% to 8.0 +/- 0.5% (P<0.0001). In contrast, the HbA1c values in the glucose-only testing group declined from 9.4 +/- 0.9% to 9.1 +/- 1.3%, a difference that was not significant. CONCLUSION: In the 3 months after a change in therapy for type 2 diabetes, weekly home testing of fructosamine, combined with therapeutic interventions based on the results, led to a more rapid and significant improvement in glycemic control than did the usual regimen of glucose-only testing.

Blood Glucose Self-Monitoring↗
PubMedDate not supplied

Experiences with single-layer biliodigestive anastomosis.

BACKGROUND/AIMS: The right technique for biliodigestive anastomosis is still being researched. The present study investigated the single-layer method. METHODOLOGY: The authors performed single-layer biliodigestive anastomosis in 153 patients between 1995 January and 2000 August. Among the operative procedures there were pancreatoduodenectomy, pancreatic head resection, pancreatic drainage operation, GEA and in a small percentage of the cases other procedures. 88.2% of the anastomoses were done with a continuous suture technique, mainly with 4/0 PDS. RESULTS: In 96 cases the diagnosis was tumor, while the others were benign diseases. Hepatico- or choledochojejunostomy was twice as much as cholecystojejunostomy. There were complications in 29.4% of the cases, from which the rate of biliary fistula was 3.9%. All fistulas healed for conservative therapy. Reoperation was in 7.1%, the operative mortality was 9.8%. Preoperatively 77.1% of the patients had cholestasis, which improved in all cases postoperatively. CONCLUSIONS: In summary the authors offer the single-layer technique for biliodigestive anastomosis.

Anastomosis, Surgical↗