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Biomedical subjects

I Magnusson

Publications and source records attributed to I Magnusson.

At least 73 records · Page 4Linked to original sources
PubMed1991

Transrectal ultrasound and computed tomography in preoperative staging of lower rectal adenocarcinoma.

A comparison of transrectal ultrasound (TRUS) and computed tomography (CT) for staging of rectal carcinoma was performed. Thirty-two patients were examined by TRUS and 30 by CT. The results of these preoperative examinations were compared with postoperative histopathological findings. TRUS had an accuracy of 81% and it predicted perirectal tumor growth with a sensitivity of 90% and a specificity of 67%, whereas the corresponding figures for CT were 52%, 67%, and 27%. These findings indicate that TRUS is more efficient than CT in staging local tumor growth in rectal cancer. Neither technique, however, can reliably identify lymph node metastases, since no correlation was found between lymph node size as observed on CT and TRUS and tumor involvement as evaluated histopathologically.

Adenocarcinoma↗
PubMed1991

Multiple primary colorectal adenocarcinomas: cytometric DNA ploidy patterns and histopathologic features.

The nuclear DNA distribution pattern was studied by means of image cytometry in 18 patients with synchronous and 7 patients with metachronous colorectal adenocarcinomas. About 80 percent of a total number of 53 carcinomas were found to consist of neoplastic cells where the nuclear DNA distribution pattern was of the aneuploid type. In 19 of the 25 patients, all carcinomas in the individual colon had identical nuclear DNA distribution patterns. Aneuploid tumors tended to appear more frequently in the sigmoid colon and the rectum than in the right colon. Carcinomas associated with an adenoma were more common in the rectum and in Dukes' A carcinomas. The results of cytometric assessments of the nuclear DNA ploidy pattern of the neoplastic cells in colorectal carcinomas have previously been found to be an independent prognostic variable. From the observations made in the present study, it is concluded that the cytometric DNA ploidy pattern of multiple primary colorectal carcinomas corresponds to that found in single carcinomas. The similarity between the two groups of cancer patients is also supported by conformity between histopathologic features and prognosis.

Adenocarcinoma↗
PubMed1991

Reproducibility of attachment level measurements with two models of the Florida Probe.

Clinical assessment of the progression of periodontitis is based on the measurement of periodontal probing attachment levels over time. In calculating these changes, duplicate measurements from fixed reference points, including cemento-enamel junctions and acrylic stents, have been used to assist in detecting progressive disease. The Florida Probe has been previously shown to improve the reproducibility of these measurements when used with an acrylic stent. The objective of the present study was to evaluate the reproducibility of 2 models of the Florida Probe, the original stent model and the modified disk model, in measuring attachment level. The disk probe differs from the stent probe in that it uses the occlusal surface of the tooth as a static reference point in calculating changes in attachment level measurements. In 10 subjects, sites were probed 2 x by 2 examiners using both types of probe. Standard deviations and intra- and inter-examiner correlations were calculated. These results demonstrate that the new disk probe yields reproducible measurements similar to the stent probe and is therefore suitable for use in longitudinal clinical studies.

Equipment Design↗
PubMed1991

Clinical, microbiological and immunological characteristics of subjects with "refractory" periodontal disease.

The aim of the present study was to analyze the relationship between attachment loss and clinical, microbiological, and immunological parameters in a group of 21 human subjects exhibiting poor response to previous periodontal therapy. All had been treated with periodontal surgery, tetracycline, and subsequent maintenance recalls to periodontists who, upon detection of disease progression, referred the subjects to our clinic. In our clinic, each subject received oral hygiene instruction and a thorough subgingival scaling and root planing utilizing as many appointments as necessary. Clinical indices, including gingival index, bleeding on probing, suppuration, plaque index, pocket depth, and duplicate measurements of attachment level from an acrylic stent, were collected at monthly intervals. Probing measurements were performed using the Florida Probe. When significant attachment loss (0.8-1.2 mm) was detected in at least 1 site, a bacterial sample was taken from that site and from a comparably deep, but non-progressing, control site. Microbial samples were enumerated by darkfield microscopy, on selective and non-selective media, and by predominant cultivable technique. Blood samples were also collected to determine antibody levels against potential pathogens. There was no difference in the amount of plaque present in sites gaining or losing attachment, but losing sites exhibited more bleeding and suppuration. 20 of the 21 subjects were tested; of these, 17 exhibited elevated serum antibody against one or more of the following microorganisms: Actinobacillus actinomycetemcomitans, Bacteroides, gingivalis, and Eikenella corrodens. However, few, if any, of the "classical" pathogens were detected in the plaque samples obtained at the time progressive disease was diagnosed. The only exception was Streptococcus intermedius, which occurred in slightly higher numbers in active sites.

Actinobacillus↗
PubMed1991

Relationship between gingival inflammation and painfulness of periodontal probing.

The relationship of gingival inflammation to the pain associated with periodontal probing was assessed at baseline (B), and 1 month (1M) and 3 months (3M) later in 46 subjects. At each of the 3 sessions, clinical measures of gingival inflammation included an observational gingival index and bleeding score. In addition, periodontal probings of all existing teeth was performed with a constant force probe (25 g). Following completion of the probing at each session, subjects rated the global painfulness of the probing using a visual analog scale for pain. Results of this study showed that judged painfulness of probing was related to clinical inflammation (bleeding score) at baseline and 1 month and suggest that the degree of periodontal inflammation is related to the pain and discomfort associated with periodontal probing.

Adult↗
PubMed1991

Subgingival microbiota in squirrel monkeys with naturally occurring periodontal diseases.

The squirrel monkey (Saimiri sciureus) has been proposed as an in vivo model for the study of subgingival colonization by suspected periodontopathogens, such as black-pigmented porphyromonads and prevotellas (BP/P). However, the indigenous microbiota of the squirrel monkey has not been well described. Therefore, in order to more fully characterize the oral microbiota of these animals, we studied two groups of squirrel monkeys from widely different sources. Group I consisted of 50 breeding colony monkeys ranging in age from 9 months to over 6 years which had been raised in captivity; group II consisted of 16 young sexually mature monkeys recently captured in the wild in Guyana. Group I animals in captivity had developed moderate to severe gingivitis, with a mean gingival index (GI) of 2.6; 52% of the sites bled, 26% had detectable calculus, and 83% had detectable BP/P. A group I subset (six animals), for which predominant cultivable microbiota was described, had a mean GI of 2.4. Colony morphology enumeration revealed that five of the six subset animals were detectably colonized with BP/P (range, 0 to 16.9%) and Actinobacillus actinomycetemcomitans (range, 0 to 3.9%); all subset animals were colonized with Fusobacterium species (range, 0.8 to 3.6%), Actinomyces species (range, 2.3 to 11%), and gram-positive cocci (range, 1.4 to 21.4%). Predominant cultivable microbiota results revealed the presence of many bacterial species commonly found in the human gingival sulcus. At baseline, group II animals were clinically healthy and had a mean GI of 1.4; 67% of the sites bled and 2.1% had calculus, and none of the animals had detectable BP/P. Neisseriae were very common in noninflamed sites. Subsequently, when inflamed sites were compared with noninflamed sites in group II animals after they had been maintained in captivity for 6 months, inflamed sites exhibited a more complex microbiota and increased proportions of gram-negative rods and asaccharolytic bacteria.

Animals↗
PubMed1991

Immune modulation of Prevotella intermedia colonization in squirrel monkeys.

Colonization of the gingival crevice by black-pigmented Porphyromonas or Prevotella spp. (BP/P), including Porphyromonas gingivalis (formerly Bacteroides gingivalis) and Prevotella intermedia (formerly Bacteroides intermedius), is thought to be an important ecological event which may result in the destruction of connective tissues supporting the teeth. Theoretically, periodontal diseases could be prevented if these or other periodontal pathogenic microorganisms did not colonize the subgingival area. The humoral immune response is one mechanism which may modulate bacterial colonization in the gingival crevice. In the present study, we tested the effect of systemic humoral immunity on subgingival colonization by indigenous P. intermedia in squirrel monkeys (Saimiri sciureus). Animals rendered essentially free of detectable BP/P by a single scaling, 10 days of tetracycline therapy, and toothbrushing three times per week were immunized with P. intermedia 1447 or were sham immunized with phosphate-buffered saline. Subsequently, all oral hygiene procedures were discontinued and five teeth in one quadrant were ligated with bacterium-soaked suture material to facilitate BP/P colonization. Immunization resulted in a significant increase in the level of immunoglobulin G anti-P. intermedia antibody in serum. Two weeks after ligation was initiated, P. intermedia could be detected in five of six sham-immunized and three of six immunized animals. Immunization was associated with a reduction in the emergence of indigenous P. intermedia in the gingival crevice.

Animals↗
PubMed1991

Pathways of hepatic glycogen synthesis in humans.

To estimate the relative contribution of the indirect pathway to liver glycogen formation in humans, different experimental approaches have been used. Although the estimates vary, it appears that in overnight fasted humans approximately 50% of liver glycogen is derived from the direct pathway following a glucose load and that the direct pathway increases to approximately 70% after the first meal of the day. While the source of the gluconeogenic substrates is still unknown, the animal data suggest that the liver itself may be an important source.

Animals↗
PubMed1990

Connective tissue repair in circumferential periodontal defects in dogs following use of a biodegradable membrane.

A biodegradable polylactic acid membrane was evaluated for its ability to enhance periodontal regeneration. In 8 Labrador dogs, circumferential defects were created around the maxillary 1st premolars. The defects were combination "1-wall vertical and horizontal". A membrane was adjusted to cover the defect on one side of the jaw, while the contralateral tooth served as control without membrane. After 3 months, healing was evaluated histologically. The results demonstrated that the amount of connective tissue repair with newly formed cementum approximated 50% of the defect height for both test and control groups. Thus, no advantage to the use of membrane was found, which is contradictory to the findings of our previous dog study using the same biodegradable membrane. The possible reasons for this difference in results are discussed relative to suggested mechanisms for membrane effects in periodontal regeneration.

Alveolar Process↗
PubMed1990

Fructose-6-phosphate cycling and the pentose cycle in hyperthyroidism.

Hepatic fructose-6-phosphate (fructose-6-P) cycling and pentose cycle activity were quantified in hyperthyroid patients. A measure of the fructose-6-P cycle was the incorporation of 14C, on administering [3-3H,6-14C]galactose, into carbon 1 of blood glucose and the 3H/14C ratio in blood glucose. The measure of the pentose cycle was the randomization of 14C to carbon 1 of blood glucose on administering [2-14C]galactose. [2-3H]Galactose was also administered, so the 3H/14C ratio in blood glucose measured the extent of equilibration of glucose-6-P with fructose-6-P. Patients given [3-3H,6-14C]galactose were restudied when euthyroid. Of the 14C from [3-3H,6-14C]galactose, 7.7-9.5% was in carbon 1 of glucose in both states. 3H/14C ratios were also the same in both states. Fructose-6-P cycling was estimated to be 13 +/- 1% the rate of glucose turnover in the euthyroid and 15 +/- 1% that in the hyperthyroid state. The pentose cycle contributed about 2% to glucose utilization, similar to previous estimates in healthy humans. As in healthy individuals, about 25% of 3H was retained in the conversion of [2-3H]glucose-6-P to glucose. Thus, the fractions of glucose turnover participating in hepatic fructose-6-P and pentose cycling are similar in hyperthyroid and healthy subjects. As a result, augmented fructose-6-P cycling does not substantially contribute to increased hepatic oxygen consumption in hyperthyroidism.

Adult↗
PubMed1990

Terlipressin (triglycyl-lysine vasopressin) controls acute bleeding oesophageal varices. A double-blind, randomized, placebo-controlled trial.

The haemostatic effect of terlipressin (triglycyl-lysine vasopressin; Glypressin) on bleeding from oesophageal varices was evaluated in a placebo-controlled, double-blind, randomized clinical trial. Patients with clinically suspected liver cirrhosis were included in the study if they had been admitted to hospital with an extensive haemorrhage within the last 24h before diagnostic endoscopy. The patients randomized after stratification for severity of liver disease. Terlipressin or placebo was administered as intravenous bolus injections every 4th h during a period of 24 to 36 h or until the clinical course necessitated active intervention (failure or withdrawal). Sixty patients entered the study; 31 patients were allocated to receive terlipressin, and 29 patients to receive placebo. Bleeding from varices was arrested in 28 of the 31 receiving terlipressin, as compared with 17 of the 29 receiving placebo (p less than 0.01). Patients receiving active drug required significantly fewer blood transfusions (p less than 0.05). Most of the side effects were classified as mild and were registered in the terlipressin group.

Acute Disease↗
PubMed1990

Clinical appearances in severe ischaemic colitis. Case report.

Ischaemic colitis was not diagnosed until laparotomy in five cases. In two it was secondary to hypotension and multiple organ failure, in two it was atherosclerotic, and one had polycythemia vera. The diagnosis should always be considered in patients with abdominal distension--with or without diarrhoea and abdominal pain--so that treatment may be instituted before the onset of peritonitis.

Aged↗
PubMed1989

Effects of somatostatin on hepatic bile formation.

Somatostatin is a peptide that has anticholeretic properties in the dog. The purpose of the present work was to investigate if somatostatin is an anticholeretic agent in humans also. The effects of intravenous infusion of somatostatin on hepatic bile flow and biliary electrolytes and secretion of biliary lipids were studied in 7 patients with complete biliary drainage who had been operated on for choledocholithiasis. Somatostatin, 250 microgram/h, was found to decrease the hepatic bile secretion by approximately 30%. The peptide also reduced the outputs of bile acids, cholesterol, and phospholipids and the outputs of sodium, potassium, and chloride. The concentrations of the biliary lipids were not significantly changed. Somatostatin inhibited the erythritol clearance in the 2 patients studied by approximately 25%. The present study thus provides evidence that somatostatin inhibits bile formation in humans. It appears as if the reduction in bile production is mainly due to decreased canalicular bile flow. It is possible that this effect of somatostatin is attributable to inhibition of bile acid synthesis or of transport-secretion of bile acids, or both.

Adult↗
PubMed1989

N-acetyl-L-tyrosine and N-acetyl-L-cysteine as tyrosine and cysteine precursors during intravenous infusion in humans.

The usefulness of N-acetyl-L-tyrosine (NAT) and N-acetyl-L-cysteine (NAC) as tyrosine and cysteine precursors during intravenous infusion was investigated in humans. Plasma levels and urinary excretion of NAT, tyrosine, NAC, and total cysteine were determined, and the site of deacetylation was examined by measuring the splanchnic and renal balances. Eleven healthy volunteers were given 5 g of either NAT or NAC as a 4-hour intravenous infusion. Plasma levels of NAT and NAC increased rapidly, accompanied by a 25% increase in tyrosine levels and a 35% decrease in total cysteine. Urinary excretion of NAT and NAC in 4 hours accounted for 56% and 11% of the infused amount, respectively. No net production of tyrosine or cysteine was found from the splanchnic area, but from the kidneys there was a small release of both tyrosine (10 +/- 3 mumol/min) and cysteine (64 +/- 3 mumol/min). We conclude that under these conditions the usefulness of NAT and NAC as precursors for the corresponding amino acids in humans is not apparent.

Acetylcysteine↗
PubMed1989

Utilization of intravenously administered N-acetyl-L-glutamine in humans.

L-glutamine is too unstable for inclusion in solutions for parenteral nutrition, but its acetylated analogue, N-acetyl-L-glutamine is not. The purpose of this three-part study was to investigate the utilization of intravenously (IV) administered acetylglutamine in humans. In study 1, nine healthy postabsorptive subjects were given 9.4 g acetylglutamine IV during four hours. In study 2, five healthy subjects were studied on two occasions following an overnight fast. They were given 9.4 g of acetylglutamine or an equivalent amount of glutamine as part of a total parenteral nutrition (TPN) regimen during 7.2 hours. A control group of five subjects was given the same TPN regimen, but without acetylglutamine or glutamine. The nutrient solution included glucose, amino acids, and a fat emulsion, supplying 9.4 g nitrogen and 6,300 kJ in a total volume of 1.8 L. In study 3, four patients were studied the day after major surgery. They were given the same TPN regimen as in study 2, containing 9.4 g acetylglutamine, during 7.2 hours. Plasma concentrations and urinary excretion of acetylglutamine and glutamine were measured in all three studies, and so were splanchnic and renal exchange of acetylglutamine and glutamine in study 1. In study 1, the plasma concentration of glutamine rose from 594 +/- 28 mumol/L to 728 +/- 26 mumol/L (P less than .001), whereas plasma levels of acetylglutamine exceeded 1,000 mumol/L in all subjects at the end of infusion. The eight-hour urinary excretion of acetylglutamine and glutamine corresponded to 18% of the infused amount of acetylglutamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Protein and amino acid metabolism during early starvation as reflected by excretion of urea and methylhistidines.

Endogenous excretion of nitrogenous products was studied during early starvation in six healthy, nonobese subjects after six days on a well-defined diet, designed to achieve net protein balance and an adequate calorie supply. The diet contained 0.5 g myofibrillar-free protein and 35 kcal/kg body weight. The subjects then fasted for three days. Urine was collected for 24-hour periods and analyzed for urea, ammonia, 3-methylhistidine, and 1-methylhistidine. Blood glucose and serum urea levels were measured daily. In a second group of subjects, muscle biopsies for determination of free amino acid concentrations were taken in the overnight fasted state and after three days of fasting. During the period with a balanced diet, urea production fell initially and stabilized after two to three days at a level of 146 +/- 15 mmol/24 h. During the period of fasting, serum urea increased from 3.0 +/- 0.4 to a maximum value of 6.2 +/- 0.7 mmol/L and urea production rose markedly, to a peak of 293 +/- 16 mmol/24 h. Ammonia excretion was 24 +/- 2 mmol/24 h before and 71 +/- 13 mmol/24 h after three days of fasting. 3-Methylhistidine excretion was stable before fasting and then rose from 154 +/- 17 to 198 +/- 17 mumol/24 h. 1-Methylhistidine excretion was unchanged during fasting. Blood glucose levels were stable at 4.8 +/- 0.2 mmol/L before fasting and then fell to 3.7 +/- 0.3 mmol/L. Intracellular concentrations of amino acids in skeletal muscle decreased markedly during fasting; after three days of fasting the glutamine concentration had fallen by 34%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗