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T Jonsson

Publications and source records attributed to T Jonsson.

13 recordsLinked to original sources
PubMed1992

Role of internal thermodynamics in determining hydrogen tunneling in enzyme-catalyzed hydrogen transfer reactions.

Previous investigations have indicated a role for hydrogen tunneling in the yeast alcohol dehydrogenase catalyzed oxidation of benzyl alcohol [Cha, Y., Murray, C. J., & Klinman, J. P. (1989) Science 243, 1325] and the bovine plasma amine oxidase catalyzed oxidation of benzylamine [Grant, K.L., & Klinman, J. P. (1989) Biochemistry 28,6597]. In the present studies, values of protium to tritium and deuterium to tritium isotope effects and their temperature dependencies have been measured using ring-substituted substrates for yeast alcohol dehydrogenase and bovine plasma amine oxidase, revealing tunneling in each case. The results of these studies indicate that hydrogen tunneling is a general phenomenon and is not limited to enzyme reactions with degenerate energy levels for bound substrates and products. An analysis of internal thermodynamics in the yeast alcohol dehydrogenase reaction shows that tunneling occurs when delta H degrees is endothermic and that the degree of tunneling appears to increase as delta H degrees decreases toward zero.

Alcohol Dehydrogenase↗
PubMed1992

Systemic piroxicam as an adjunct to combined epidural bupivacaine and morphine for postoperative pain relief--a double-blind study.

In a randomized, double-blind, placebo-controlled trial, we assessed the value of adding rectal piroxicam to a low-dose epidural regimen for postoperative pain relief. Forty-four patients scheduled for major upper abdominal surgery during combined thoracic epidural (bupivacaine + morphine) and general anesthesia were studied. Postoperative analgesia was achieved by using epidural bupivacaine (10 mg/h) plus morphine (0.2 mg/h) for 72 h. In addition, the patients randomly received a placebo or rectal piroxicam (40 mg 12 h before surgery, 20 mg with premedication, and 20 mg every 24 h for 72 h). Pain was evaluated every 4 h at rest, during coughing on demand, and during mobilization. The sensory level of analgesia was evaluated by pinprick. We found no significant difference between piroxicam and placebo with regard to postoperative pain scores or need for supplementary analgesics. Thus, we were unable to demonstrate enhanced analgesia by adding piroxicam to an otherwise very effective low-dose epidural bupivacaine and morphine treatment after upper abdominal surgery.

Abdomen↗
PubMed1992

Effect of suture technique on early healing of intestinal anastomoses in rats.

OBJECTIVE: To see if the site and tension of sutures had any influence on early breaking strength in intestinal anastomoses. MATERIAL: 161 Male Wistar rats. INTERVENTIONS: First experiment: after laparotomy and division of the ileum an inverted end to end anastomosis was made in a single layer with 14 interrupted sutures of 7/0 polypropylene. All sutures were inserted 3 mm from the cut edges. The rats were randomly allocated to one of four groups according to the size of the loop of suture used: tight (n = 38), 0.4 mm (n = 22), 0.9 mm (n = 35), or 2.0 mm (n = 24). Second experiment: the method used was the same except that sutures were placed 1.5 mm from the cut edges and the rats were randomly allocated to one of two groups according to the size of loop of suture--tight (n = 20), or 0.9 mm (n = 22). MAIN OUTCOME MEASURES: Breaking strength measured in a tensiometer (both experiments); and myeloperoxidase activity/g tissue, hydroxyproline content and solubility/biopsy specimen (first experiment only). RESULTS: Breaking strength decreased proportionally the tighter the sutures were tied, and the differences were significantly greater when the sutures were placed closer to the cut edges. Anastomotic myeloperoxidase activity, hydroxyproline content, and soluble: total hydroxyproline ratio were similar in all groups. CONCLUSION: Tight sutures may promote proteolytic tissue degradation by reducing the local availability of circulating proteinase inhibitors.

Anastomosis, Surgical↗
PubMed1991

[Continuous epidural treatment of cancer pain using a portable infusion pump].

Treatment of cancer pain with opioids through an epidural catheter, with a portable infuser has been recorded in 20 patients retrospective. In general there was a good acceptance of the treatment, which often could liberate the patients from close contacts to the pain clinic. There were not recorded adverse effects in relation to the infuser treatment. One patient had systemic adverse effects because of a very high daily opioid dose. The Pharmacia Deltec infuser employed has proven very secure and easy to handle.

Adult↗
PubMed1991

Neutrophil-dependent decrease in early wound margin strength.

We evaluated the effect of neutropenia or administration of a serine proteinase inhibitor on the early suture-holding capacity of intestinal anastomoses in rats. One group of rats was treated with antineutrophil serum, and another group received the soybean trypsin inhibitor. Controls received inactivated serum or saline. Anastomotic suture-holding capacity (breaking strength), myeloperoxidase activity, and collagen were measured 0 and 72 hours after surgery. Suture-holding capacity decreased by 70% in controls and 35% in soybean trypsin inhibitor-treated rats, but remained on level with immediate postoperative strength in neutropenic rats, where low myeloperoxidase levels reflected effective wound margin neutropenia. Collagen content and solubility were similar in all groups. These findings indicate that reduction in early wound margin strength is neutrophil dependent, and that neutrophil serine proteinases are important mediators in that process.

Anastomosis, Surgical↗
PubMed1991

Diathermy-induced inflammation does not affect suture holding capacity of intestinal anastomoses.

We compared the suture holding capacity of rat intestinal anastomoses after division of the bowel with scissors or diathermy. Two sets of experiments differing in suture technique were done. In one set the amount and solubility of anastomotic collagen were measured, and neutrophil accumulation quantified with a myeloperoxidase (MPO) assay. MPO activity 24 h after surgery was 60% higher (p less than 0.05) after division with diathermy than after division with scissors. Suture holding capacity (breaking strength) decreased by approximately 70% (p less than 0.001) in both groups when sutures were inserted near the bowel edges, while no decrease was noted when sutures were inserted at a farther distance, regardless of the mode of bowel division. After 7 days MPO levels approached baseline values in both groups and the bowel always ruptured outside the anastomosis. Collagen content was not adversely affected by diathermy. Although the reduction in early anastomotic strength may be mediated by local neutrophil activity, suture holding capacity was not influenced by the increased neutrophil accumulation elicited by diathermy.

Anastomosis, Surgical↗
PubMed1990

Anterior cruciate ligament repair with and without augmentation. A prospective 7-year study of 51 patients.

A prospective comparison was made of the 7-year results of repair of the acutely ruptured anterior cruciate ligament with and without augmentation using the longitudinal patellar retinaculum. The knee stability was evaluated by clinical tests and by a specially constructed testing device. In the repair group, 6/22 had unchanged activity and intensity levels compared with 24/29 in the augmentation group. Lysholm's functional score was higher in the augmentation group. All the clinical tests and all the objective measurements except Lachman's test showed better stability in the augmentation group.

Adolescent↗
PubMed1979

Individual mercury exposure of chloralkali workers and its relation to blood and urinary mercury levels.

On two occasions, chloralkali workers were investigated with regard to personal air mercury exposure, blood mercury and urinary mercury. The first investigation (13 workers, 2 weeks) was made at an exposure above the threshold limit value (64 microgram/m3, range 36--112), the second (16 workers, 8 weeks) at a lower exposure (23 microgram/m3, range 15--43). At the higher level of exposure, good correlations were found between air exposure and blood or urinary mercury for the group, but not for individuals. At the lower level, the correlations were less pronounced for the group. For individuals, the best correlation was found between mean air exposure during one week and blood mercury about half a week later. Other individuals, mainly the least exposed, showed no such correlation. Corresponding correlations were not found for urinary mercury. The urinary excretion rate was determined only for the last few hours of the workday, but the results agree with earlier investigations of 24-h excretion on a group basis. The threshold limit value for mercury in air (50 microgram/m3) corresponds to 150--175 nmol Hg/1 blood (= 30--35 microgram/1) for the group, with large individual variation.

Adult↗
PubMedDate not supplied

Augmentation with the longitudinal patellar retinaculum in the repair of an anterior cruciate ligament rupture.

Most authors advocate repair of the acutely ruptured ACL by augmentation or some form of primary reconstruction. Strong autogenous tissues like the patellar and semitendinosus tendons and the iliotibial band are often used when augmentation is the surgical choice. This paper describes a surgical procedure using a strip of the longitudinal patellar retinaculum as an augmentation of the repaired ACL. The retinaculum adds stability and strength to the repaired ACL during the healing period. Moreover, the retinaculum may enhance the healing process of the ruptured ACL by revascularization. It may also increase the stimulation of synovial tissue proliferation over the repaired ACL. Twenty-eight patients have been clinically and objectively evaluated at a mean follow-up time of 78 months (range, 63 to 94 months). The patients' own evaluation of their knee function was excellent or good in 86% (24 patients). Eighty-two percent (23 patients) could return to their preinjury activities at the same intensity level as before injury, whereas at an intermediate followup at 18 months only 64% (18 patients) had done so. Anterior tibial displacement was objectively evaluated at both followups by means of the anterior drawer test, with 20 degrees to 30 degrees and 90 degrees of knee flexion, in a testing device. The operated knee usually showed a tendency to a slightly increased anterior displacement when compared with the uninjured knee. The repair of a ruptured ACL with an augmentation using the longitudinal patellar retinaculum has been shown to give good results after more than 5 years.

Adolescent↗
PubMedDate not supplied

Development of stress ulcers assessed by gastric electrical potential difference, pH of gastric juice, and endoscopy in patients in the intensive care unit.

OBJECTIVE: To assess measurement of gastric electrical potential difference, pH of gastric mucosa, and endoscopic findings in patients in intensive care units who are at risk of developing stress ulcers. DESIGN: Open comparison with age- and sex-matched control subjects. SETTING: Herlev Hospital, Denmark. SUBJECTS: Sixteen consecutive patients with no history of gastrointestinal haemorrhage, coagulopathy, or ulcer disease who had been admitted to the intensive care unit, and 16 age- and sex-matched outpatients with normal endoscopic findings. INTERVENTIONS: Upper gastrointestinal endoscopy, during which any lesions that were found were scored according to severity, the gastric potential difference, and the pH of gastric juice were measured. OUTCOME MEASURES: Correlation between the incidence of stress ulceration found at endoscopy, gastric potential difference, and gastric pH. RESULTS: Gastric potential difference was significantly reduced and gastric pH significantly increased in the patients in the intensive care unit (p less than 0.05 in both cases), all of whom had stress ulcers in more than one gastric segment. Nine of the patients had gastric pH readings of greater than 4. CONCLUSION: Gastric electrical potential difference may be useful measurement for the assessment of stress ulceration in patients in intensive care units.

Adult↗