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Biomedical subjects

W Becker

Publications and source records attributed to W Becker.

At least 415 records · Page 23Linked to original sources
PubMed1987

Reduction of DNA-polymerase beta activity of CHO cells by single and combined heat treatments.

The effect of single and combined heat treatments on the activity of DNA polymerase beta was studied in CHO cells. The activity of polymerase beta was determined by measuring the amount of [3H]TTP incorporated into activated calf thymus DNA in the presence of aphidicolin, a specific inhibitor of DNA polymerase alpha. Biphasic response curves were obtained for all temperatures tested (40-46 degrees C) showing the sensitivity to decrease during heating. A constant activation energy of Ea = 120 +/- 10 kcal/mole was found for the initial heat sensitivity, whereas the Arrhenius plot for the final sensitivity is characterized by an inflection point at 43 degrees C with Ea = 360 +/- 40 kcal/mole or Ea = 130 +/- 20 kcal/mole for temperatures below or above 43 degrees C, respectively. The observed decrease of the polymerase activity is not due to a decrease in the number of active enzyme molecules but to a change in its affinity, since the inhibition is reversible when increasing concentrations of TTP are applied. When acute or chronic thermo-tolerance was induced by a priming heat treatment at 43 degrees C for 45 min followed by a time interval at 37 degrees C for 16 h or by a preincubation at 40 degrees C for 16 h, respectively, the thermal sensitivity of polymerase beta was lowered by a factor of up to 5. By contrast, pretreatment at a higher temperature followed by a lower temperature (step-down heating) did not alter the sensitivity of polymerase beta to the second treatment. The results indicate that heat-induced cell death cannot be the consequence of the reduction of the polymerase beta activity, confirming earlier studies on this subject.

Animals↗
PubMed1987

Faecal alpha-1-antitrypsin and excretion of 111indium granulocytes in assessment of disease activity in chronic inflammatory bowel diseases.

Intestinal protein loss in chronic inflammatory bowel diseases may be easily determined by measurement of alpha-1-antitrypsin (alpha 1-AT) stool concentration and alpha 1-AT clearance. Both parameters were significantly raised in 36 and 34 patients respectively with chronic inflammatory bowel diseases, compared with eight patients with non-inflammatory bowel diseases, or 19 healthy volunteers. There was wide range of overlap between active and inactive inflammatory disease. Contrary to serum alpha 1-AT, faecal excretion and clearance of alpha 1-AT did not correlate with ESR, serum-albumin, orosomucoid, and two indices of disease activity. A comparison of alpha 1-AT faecal excretion and clearance with the faecal excretion of 111In labelled granulocytes in 27 patients with chronic inflammatory bowel diseases, showed no correlation between the intestinal protein loss and this highly specific marker of intestinal inflammation. Enteric protein loss expressed by faecal excretion and clearance of alpha 1-AT does not depend on mucosal inflammation only, but may be influenced by other factors.

Adolescent↗
PubMed1987

Leucocyte elastase in chronic inflammatory bowel diseases: a marker of inflammatory activity?

Leucocyte elastase is a neutral proteinase which plays an important role in the pathogenesis of inflammatory disorders. Infiltration of bowel mucosa by neutrophil and eosinophilic granulocytes is a characteristic feature of chronic inflammatory bowel diseases. We studied plasma elastase in 44 patients suffering from Crohn's disease or ulcerative colitis. Plasma levels were significantly higher in these patients compared to 7 patients with non-inflammatory bowel diseases or 53 healthy controls. Elevated plasma levels were more often found in patients with active inflammation than in those with inactive disease. Elastase did neither correlate with leucocyte counts, serum albumin, ESR, alpha 1-proteinase inhibitor and orosomucoid nor with clinical indices or the faecal excretion of 111In-labelled granulocytes. In serial studies of 15 patients, elastase did not always run parallel to the disease activity. We conclude that plasma elastase does not reliably indicate the inflammatory activity in chronic inflammatory bowel diseases.

Adult↗
PubMed1987

Root isolation for new attachment procedures. A surgical and suturing method: three case reports.

A surgical and suturing method is described for the subgingival placement of Gore-tex periodontal material during new attachment procedures. The periodontal material isolates the root surface from epithelium and gingival connective tissue. Three cases were treated. Clinical new attachment was evident from clinical probings and reentry. The term "open probing new attachment" describes the type of tissue that was evident at reentry after treatment of a Class III furcation. A combination of new bone and "open probing new attachment" was evident after one-wall defects were treated adjacent to a mandibular cuspid. A two-wall defect was treated and biopsied three months later. A reference notch was placed 1 mm coronal to the apical aspect of the defect. Histologic examination of the biopsy showed new bone, cementum and periodontal fibers coronal to the notch. Clinical and histologic new attachment was achieved using the technique for root isolation. The long-term predictability and stability of this type of new attachment is not known at this time.

Connective Tissue↗
PubMed1987

Plasma amino acid clearance as an indicator of hepatic function and high-energy phosphate in hepatic ischemia.

A major function of the liver is to maintain normal levels of plasma amino acids. This function may depend in part on tissue levels of high-energy phosphate. Experiments were performed in adult mongrel dogs to assess the relationship between plasma amino acid clearance (PAAC) and tissue high-energy phosphate after 90 minutes of warm hepatic ischemia. In addition, when PAAC was assessed in the anhepatic dog, PAAC fell to low levels after hepatectomy. After 90 minutes of warm ischemia, both tissue adenosine triphosphate (ATP) and PAAC fell to low levels, with PAAC similar to those levels observed in anhepatic dogs. Recovery of ATP and PAAC progressed over a 48-hour period but did not reach control values. Mortality rate was 33% in a group of 12 animals at 48 hours after ischemia. At 24 hours after ischemia, total free plasma amino acid levels were significantly higher in those animals that were dying as compared with those that were surviving (4352 mumol/L versus 2850 mumol/L; p less than 0.05). There was a strong correlation between PAAC and ATP (r = 0.81). PAAC appears to be an indicator of hepatic functional recovery and tissue ATP levels after ischemia.

Adenine Nucleotides↗
PubMed1986

[Scintigraphy and sonography in the diagnosis of thyroid autonomy. A retrospective study of 526 patients].

The place of scintigraphy and ultrasonography in diagnosis was analysed retrospectively in a series of 526 patients with confirmed thyroid autonomy. Male:female ratio was 1:4.6; peak age incidence was in the sixth decade. 5.6% of patients were younger than 30 years and in each case had a sonographic focus. A normal thyroid size was found in 6.5% on palpation and in 10% by ultrasound. Normal thyroid function was found in 287 patients (56%), of whom 48% had a positive TRH test, the remainder being hyperthyroid. Unilocular autonomy was present in 57%, multilocular in the remainder. With increasing degree of autonomy there was an increase in echo-density. In 351 patients (74%) the adenoma was echo-poor, in 16% echo-normal and in 10% echo-dense. Focal findings on sonography were noted in 94% of patients. The incidence of thyroid carcinoma was 1.5% (2 of 136 patients with goitre resection), the carcinoma not being located in the autonomous tissue. It is concluded that a thyroid of normal size does not exclude autonomy. Patients younger than 30 years require scintigraphic examination only if there are focal signs. Echogenicity of a thyroid focus does not correlate with function. The incidence of cancer in the presence of autonomy is low. There was no case of thyroid carcinoma in the autonomous region.

Adult↗
PubMed1986

111In-oxine-labelled white blood cells in the diagnosis and follow-up of Crohn's disease.

Prospectively, 43 patients with Crohn's disease (41 clinically active, 2 clinically inactive) and 7 patients with irritable bowel syndrome were examined by 111In-oxine-labelled leukocytes ('mixed' leukocyte preparations, n = 8; 'pure' granulocyte preparations, n = 42). The number of scintigraphically diagnosed inflamed bowel segments correlated significantly (r = 0.95, p less than 0.001) with the number of radiologically and endoscopically diagnosed segments. The exact localization of the diseased ileum may be difficult by scintigraphy. One complicating abscess and two fistulas were correctly diagnosed. The percentage of fecal excretion of radiolabelled leukocytes is highly specific for intestinal inflammations. It correlates significantly with the erythrocyte sedimentation rate (r = +0.69, p less than 0.001), serum albumin (r = -0.54, p less than 0.001), orosomucoid (r = +0.65, p less than 0.001), and with the A.I. (van Hees) (r = +0.67, p less than 0.001). In the follow-up of 9 patients, the percentage of fecal excretion decreased or increased more rapidly, but in correlation with the CDAI, A.I., or ESR. The authors conclude that this method is an alternative to common methods and that it is superior in primary diagnosis in patients with severe disease, bowel stenosis, abscesses, and after surgery. After clinical and biopsy-proven diagnosis of Crohn's disease, the special value of the leukocyte scan lies in the noninvasive follow-up of patients and its potential of localizing inflamed bowel segments and assessing disease activity.

Colon↗
PubMed1986

Quantification of parasite development in the host-parasite system Biomphalaria glabrata and Schistosoma mansoni.

The visceral mass of Biomphalaria glabrata uninfected or infected with Schistosoma mansoni was serially sectioned. The amount of hepatopancreas tissue and of parasite tissue was quantified. In pool-infected snails the volume of the whole visceral mass increased very significantly until week 6 and then decreased. Due to the growing parasites the volume of the visceral mass in infected snails was at most times higher when compared with uninfected snails of the same dimensions. Two weeks p.i. there was a permanent and significant increase of parasite tissue until week 6. During this time the amount of hepatopancreas tissue still increased. From this time onwards till week 12 the proportion of parasite tissue remained rather constant, indicating a kind of regulation, whereas the hepatopancreas tissue decreased to about one-third of the volume found in uninfected snails of the same shell diameter. Compared with infections by a single miracidium there was a significant increase in parasite tissue after infection with two miracidia. Infections with more miracidia (5, 10, and 20) gave no significant further increase. This also demonstrates a kind of regulation. Mortality rate, growth rate and egg production were studied during an infection period of 12 weeks.

Animals↗
PubMed1986

Retention of linoleic acid in carcass lipids of rats fed different levels of essential fatty acids.

Rats of an inbred Sprague-Dawley strain were fed purified diets with low (0.3% of total energy), normal (3%) or high (10%) content of essential fatty acids (EFA) for at least three generations. Two 30-day-old rats with similar weights were chosen from one litter. One was killed; weight increase and food consumption of the other rat was measured for 15 days. Total lipid content and fatty acid composition in total lipid and lipid classes were determined in both rats. Seven pairs of rats from each group were treated in the same way. Calculations based on amount of linoleic acid ingested and retained in the carcass lipids showed that 50% of the ingested linoleic acid was retained in the low EFA rats compared to 10-15% in the normal and high EFA rats.

Animals↗
PubMed1986

Essential fatty acid deficiency in rats: effects on arachidonate metabolism, generation of cyclooxygenase products and functional responses in neutrophils.

Linoleic and arachidonic acid concentrations in neutrophils from rats maintained on a diet with only 0.3% of the energy content as essential fatty acid (EFA, EFAD group) were reduced by 70 +/- 2.2% and 34.8 +/- 5.2%, respectively, compared with controls fed a diet with a normal 3% EFA content. Neutrophil chemiluminescence and aggregation induced by f-Met-Leu-Phe was substantially reduced in the EFAD group. Production of 6-keto-prostaglandin F1 alpha and thromboxane B2 were significantly lower in the EFAD neutrophils when stimulated by the ionophore A23187, whereas there was no difference when leukotriene B4 was used as stimulus.

Animals↗
PubMed1986

[Scintigraphic diagnosis of inflammatory small bowel stenoses in Crohn disease using 111In oxine-labeled leukocytes].

17 patients with known small bowel involvement in Crohn's disease (clinically active, n = 14; clinically inactive, n = 3) were examined within 8 days via barium enemas of the small bowel (Pansdorf's method or enteroclysis) and by 111In-oxine labelled leucocytes. From 19 radiologically diagnosed small bowel stenoses 14 were classified as inflammatory and 5 as non-inflammatory. The leucocyte scan also showed 14 inflammatory stenoses. The not inflamed stenoses could not be diagnosed scintigraphically. The barium enemas of the small bowel and the leukocyte scans both correctly diagnosed the acute inflamed segments. The inability to show non-inflamed segments (n = 5) and to localise small bowel stenoses exactly is disadvantageous in the scan. The advantage of the leucocyte scan is a non-invasive examination without specific bowel preparation and the possibility to diagnose additionally inflamed large bowel segments (n = 4), fistulas and abscesses (n = 2). The leucocyte scan offers a useful expansion of the diagnostic tools in small bowel diseases, especially in radiological problems in patients with Crohn's disease.

Adult↗
PubMed1986

Long-term threshold stability with porous tip electrodes.

Experience with 163 unipolar tined porous endocardial electrodes is reported. One patient required repositioning of the electrode because of exit block. There were no other complications in the entire series of patients. All of the patients had low chronic stimulation thresholds. The mean pulse width 24 hours after implantation was 0.0534 +/- 0.0128 ms. Seventy-four patients were restudied six months after implantation. The mean pulse width threshold was then 0.07432 +/- 0.0775 ms. Fifty-four patients were evaluated one year after lead implantation. The mean pulse width threshold was then 0.0611 +/- 0.0230 ms. The pulse generator was reprogrammed to a lower pulse width in all of the patients. This permitted a substantial prolongation of the pulse generator life. The cost effectiveness of the pulse generator was also greatly improved by pacing with reduced pulse widths. In an additional 16 patients, the voltage amplitude was reduced from 5.0 volts to 2.5 volts. This permitted an even greater increase in the pulse generator longevity.

Electrodes, Implanted↗
PubMed1986

Clinical and volumetric analysis of three-wall intrabony defects following open flap debridement.

Fourteen defects were treated with flap debridement procedures using the Prichard principle of epithelial exclusion. Six defects were considered to be medium in width (3-4 mm), seven defects were wide (greater than 4 mm), and one defect was narrow (1-2 mm). The parameters studied were changes in gingival and plaque scores, attachment levels, and bone scores. All defects were reentered 9 to 16 months after surgery and changes between the pretreatment and posttreatment bone levels were recorded. The mean gain in probing attachment level was 2.76 mm. The mean amount of defect fill measured from models was 2.56 mm, while the mean defect fill from direct measurements was 3.26 mm. The percentage defect fill measured from study models was 61%. Crestal resorption was 9.7%. The average change in defect volume unadjusted for crestal resorption was 61.8 cu mm. Seven defects had a 50% or greater decrease in defect volume, while seven defects had less than a 50% change. Intrabony defects where calculus is present on the involved tooth surface prior to therapy will repair with substantial amounts of bone as a result of open debridement.

Alveolar Process↗