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Biomedical subjects

B Holm

Publications and source records attributed to B Holm.

At least 73 records · Page 4Linked to original sources

Unilateral, isometric bite force in 8-68-year-old women and men related to occlusal factors.

Unilateral bite force was studied in 63 women and 59 men, 8-68 yr of age. The subjects had a minimum of 24 teeth and no symptoms or signs of disorders of the craniomandibular system. Bite force was stronger in men (522 N) than in women (441 N). It increased with age until 25 yr (P less than 0.0001). The level decreased significantly after this age in women, whereas it only tended to decrease in men and not until after 45 yr of age. Body height was positively associated with force. However, the strongest correlation (r: 0.43-0.49, P less than 0.01) with adult bite force was occlusal contact. The normal bite-force values with important determining factors provide reference data for screening of elevator muscle strength in routine examination of craniomandibular function.

Adolescent↗

Antibiotic prophylaxis in acute nonperforated appendicitis. The Danish Multicenter Study Group III.

In a prospective, block-randomized, multicenter study, the safety and efficacy of cefoxitin in preoperative prophylaxis were studied. 1735 patients undergoing appendectomy were evaluable, and half of these patients received 2 g of cefoxitin before undergoing operation. The patients were divided into three groups: patients with a normal appendix, patients with an acutely inflamed appendix, and patients with a gangrenous appendix. The study showed for each group a significant reduction of the incidence of wound infection in patients receiving prophylaxis. However, intra-abdominal abscess formation was not influenced by preoperative antibiotic prophylaxis. Consequently, routine preoperative prophylaxis is recommended before appendectomy.

Abdomen↗

The effect of hydralazine on steady-state plasma concentrations of metoprolol in pregnant hypertensive women.

We have studied the plasma concentrations levels of metoprolol after its twice daily administration in a dose of 50 mg for 4 days in ten, hypertensive pregnant women to the during monotherapy and in combination with 25 mg of hydralazine given twice daily. Hydralazine increased the median AUC and Cmax of metoprolol by 38% and 88% respectively, and decreased the tmax from 1.5 h to 1.0 h. Hydralazine had no effect on the plasma concentrations of alpha-OH-metoprolol. These results suggest that the effect of hydralazine on metoprolol plasma concentrations is primarily due to a reduction in first-pass elimination.

Adult↗

Interactions of human blood platelets with three circulating plasma fibrinogens of different molecular weights.

The ability of three naturally occurring human fibrinogen species, HMW, LMW and LMW', to support ADP-induced platelet aggregation was investigated and compared to their ability to bind to gel-filtered platelets. Whereas HMW had intact subunit chains, LMW and LMW' had defined lesions in the C-terminal part of one (LMW) or both (LMW') of the A alpha-chains. The ADP-induced aggregation of gel-filtered platelets in the presence of LMW was about 75 per cent of that obtained with HMW (0.2 mumol/l of fibrinogen and 10 mumol/l of ADP). A mixture of equal amounts of LMW and LMW' showed around 50% decrease in aggregation. Compared to these difference in aggregation co-factor function, direct binding to gel-filtered platelets was less affected by the A alpha-chain degradation. However, a difference between LMW, LMW' and HMW binding was significant when the fibrinogens labelled with two different isotopes of iodine were present simultaneously. These results demonstrate that naturally occurring plasma fibrinogens differ in their interactions with platelets. As the HMW/LMW ratio changes during the acute phase, this may be of physiological significance.

Adenosine Diphosphate↗

The predictive value of the third day temperature in the decision whether to continue or terminate antibiotic treatment in perforated appendicitis.

The third day temperature is frequently used in the decision whether to continue or terminate antibiotic treatment following appendicectomy in perforated appendicitis. To assess the value of the third day temperature in predicting intraperitoneal infectious complications we studied 235 consecutive patients treated with a 3-day course of cefoxitin after surgery for perforated appendicitis. The results demonstrated that regardless of the level of elevated temperature chosen, the predictive value ranged between 16 and 33%. In consequence, elevated third day temperature per se does not provide any rational basis for continuing antibiotic treatment in order to prevent intraperitoneal infectious complications following appendectomy in perforated appendicitis.

Abdomen↗

Binding properties on Sepharose insolubilized fibrinogen and fibrin, of various species of fibrinogen and fibrin solubilized in plasma.

Radiolabelled tracers of fibrinogen, fibrin des-AA and fibrin des-AABB were solubilized in recalcified, prothrombin depleted plasma, adding either 125I-fibrin des-AA or 125I-fibrin des-AABB together with 131I-fibrinogen, and subsequently subjected to affinity chromatography, utilizing short columns of Sepharose insolubilized preparations of fibrinogen, fibrin des-AA and fibrin des-AABB, respectively. Two naturally occurring fibrinogen species, of high molecular weight (HMW; m.w. 340.000) and of low molecular weight (LMW; m.w. 305.000) exhibited similar binding characteristics, as judged by adsorption and desorption experiments. In subsequent studies all tracer preparations were derived from HMW-fibrinogen. Sepharose insolubilized fibrinogen favoured the adsorption of soluble fibrins as compared to fibrinogen in solution; the adsorption of soluble des-AA fibrin was similar to that of soluble des-AABB fibrin. To insolubilized fibrin, adsorption of soluble tracers of fibrinogen and fibrins increased considerably, and soluble fibrins were no longer preferentially adsorbed. The latter observation was supported by similar desorption characteristics of these tracers. These findings may indicate that the E-domains of soluble fibrin become largely inaccessible to the D-domains of Sepharose insolubilized fibrinogen, probably due to complexing fibrinogen in plasma. Furthermore, adsorption was largely related to the a-epitope of insolubilized fibrin.

Animals↗

The release of small amounts of fibrinopeptide-B (FPB) is of critical importance for the thrombin clotting time.

When fibrinogen is clotted with thrombin, mainly fibrinopeptide-A (FPA) is released at gel point, the FPB-release being delayed. The present study present evidence that the small amounts of des-AABB fibrin found at visible gelation improves polymerization, thereby determining the thrombin clotting time. 1. Purified fibrinogen was clotted with thrombin or Reptilase, peptide release monitored radioimmunologically. With thrombin, significantly less fibrin (released FPA) was necessary for gel formation than when Reptilase was used. Furthermore, approximately 10% of the available FPB had been released by thrombin at gel point. 2. Polymerization of monomers prepared by incubation of fibrinogen with Reptilase (des-AA) and thrombin (des-AABB) in urea, were examined by light scattering. Des-AA fibrin monomers polymerised after a lag-phase of 4 minutes. When 20% of these monomers were substituted with des-AABB monomers, the lag was reduced to 1 1/2 minutes. 3. Finally, polymerization of preformed des-AA monomers was studied with and without the addition of small amounts of thrombin, and the FPB-release monitored. The presence of 0.04 NIH U/ml of thrombin reduced the lag from 10 minutes to 3 minutes. At this time approximately 10% of FPB had been released. It is concluded that even small amounts of des-AABB fibrin substantially improves polymerization of des-AA fibrin.

Blood Coagulation Tests↗

Half life and incorporation into venous thrombi of the normally occurring plasma fibrinogen fractions HMW and LMW.

The main plasma fibrinogen species, high molecular weight fibrinogen (HMW, mw. 340,000) and LMW (mw. 305,000), displaying different in vitro properties, were examined as to half-life and incorporation into venous thrombi (DVT). Total plasma fibrinogen and relative amounts of HMW were measured pre- and postoperatively in eighteen patients undergoing total hip arthroplasty, and related to the occurrence of deep vein thrombosis, as determined by the fibrinogen uptake test (FUT). Total fibrinogen and HMW did not disclose significant differences between scan-negative and scan-positive groups. HMW and LMW, prepared from purified fibrinogen, were labelled with I125 and I131, injected simultaneously and the incorporation into thrombi registered by leg-scanning. In 5 patients demonstrating a positive FUT, HMW as well as LMW were incorporated approximately to the same extent. This result implies that neither of these fibrinogen fractions offer any advantage as compared to ordinary fibrinogen when used for FUT. The half-lives of HMW and LMW were calculated from the elimination curves of the plasma clot-radioactivity. In all the surgical patients (n = 10) as well as in the two medical DVT-patients and in two healthy volunteers the half-life of LMW was approximately 10% longer than that of HMW.

Fibrinogen↗

Absorbed doses from intraoral radiography with special emphasis on collimator dimensions.

Thermoluminescence dosimeters were used in a phantom head and on patients to measure the absorbed dose to organs of special interest from full surveys with intraoral films (20 exposures) and single bitewing exposures. Two x-ray machines were used, operating at 65 kVp. The apertures of the circular tube collimators had diameters of 55 mm and 48 mm. Rectangular (35 mm X 44 mm) tube collimators were also used. The distance from the x-ray focus to the open end of the collimators (FSD) was 0.20 and 0.35 m. Exposure values for Kodak Ultra-Speed film (speed group D) were used. The maximum skin dose measured from the full surveys decreased by 25 per cent on changing from the circular to the rectangular apertures. Using 0.35 m FSD and rectangular collimator the maximum skin dose was 13 mGy. The absorbed doses to the salivary glands and the thyroid gland were significantly reduced on changing from circular to rectangular apertures. The doses in the central part of the parotid and the thyroid glands were then 0.5 and 0.12 mGy, respectively, from a full survey with 20 intraoral films. With a leaded shield the thyroid dose was reduced to 0.05 mGy. All dose values could be further reduced by 40 per cent by using Kodak Ektaspeed film (speed group E).

Equipment Design↗

Three days cefoxitin in perforated appendicitis.

This study was undertaken to assess the efficacy and safety of a 3-day course of treatment with Mefoxitin (cefoxitin sodium, MSD) in patients with perforated or ruptured appendicitis. A series of 235 patients undergoing surgery for perforated or ruptured appendicitis were treated with cefoxitin for 3 days. Twenty-four patients (10%) developed wound infection and 28 (12%) developed an intra-abdominal abscess postoperatively. No side effects were observed during the study. Compared with the results of our previous series, where a 5-day course of cefoxitin was used, the incidence of wound infection was similar. However the incidence of intra-abdominal abscesses in the present series was significantly higher (p less than 0.01). The results seem to indicate that a 3-day course of cefoxitin is as effective as a 5-day course in controlling the incidence of wound infection following surgery for perforated or ruptured appendicitis, whereas the 3-day course seems to be inferior to a 5-day course in controlling the incidence of intra-abdominal abscesses.

Abscess↗

Polymerization properties of two normally circulating fibrinogens, HMW and LMW. Evidence that the COOH-terminal end of the a-chain is of importance for fibrin polymerization.

The plasma fibrinogen fractions HMW (mw 340,000) and LMW (mw 305,000) were prepared from purified (beta-alanine precipitated) fibrinogen by step-wise precipitation with ammonium sulfate. The thrombin clotting times were 14" and 20" respectively. The enzymatic phase of coagulation, measured as release of fibrinopeptide-A during incubation with thrombin, was found to be identical for HMW and LMW. Polymerization was studied by light scattering (at 605 nm) using preformed monomers (des-AA and des-AABB) prepared from HMW and LMW in the presence of 3.3 M urea by incubation with thrombin (100 NIH U/ml final conc.) and reptilase (1 U/ml final conc.). The HMW-monomers polymerised at a substantially higher rate than the corresponding LMW-monomers. Thus, the prolonged clotting time of LMW was explained by retarded polymerization. It is suggested that the -COOH terminal end of the a-chain, containing the molecular difference between HMW and LMW, is of importance for polymerization. Furthermore, the release of fibrinopeptide B (des-AABB-monomers) improved polymerization properties in HMW as well as in LMW, and all types of monomers polymerised more rapidly in the presence of Ca++.

Fibrin↗

Evidence that changes in fibrinogen quality during acute phase reactions are of major importance for the amount of heparin precipitable fraction (HPF).

The influence of qualitative and quantitative changes in plasma fibrinogen upon the amount of heparin precipitable fraction (HPF), obtained during the course of acute disease states, were examined. Whereas fibrinogen in plasma includes 3 species of different molecular weights (HMW, LMW, LMW'), fibrinogen in HPF, from normal as well as from "acute phase" plasma, consisted almost exclusively of HMW-fibrinogen (3% SDS-PAGE). Sub-unit chain electrophoresis (10% PAGE-SDS and two-dimensional electrophoresis) did not disclose any signs of abnormalities in the fibrinogen precipitated in HPF. Studies on patients revealed that the composition of plasma fibrinogen changed (increased HMW) during the course of acute myocardial infarction and following hip operations, and indicated that the amount of HPF was governed by the relative amount of HMW-fibrinogen as well total fibrinogen. This assumption was strengthened by quantitating the amount of HPF obtained after addition of highly purified HMW and LMW fibrinogen to normal and "acute phase" plasma. It is concluded that fibrinogen quality (per cent HMW or HMW/LMW ratio) is of major importance for the amount of HPF, thereby explaining some of the HPF-variations seen during the course of acute diseases.

Acute Disease↗

Purification and characterization of 3 fibrinogens with different molecular weights obtained from normal human plasma.

Fibrinogen was purified from fresh citrated human plasma by precipitation with beta-alanine in the presence of citrate and protease inhibitors. From this material, fractions corresponding to the HMW (high molecular weight), LMW and LMW' fibrinogen fractions of plasma were obtained by step-wise precipitation with ammonium sulfate. Electrophoresis revealed that HMW was contaminated with 4% LMW, LMW was contaminated with 6% HMW, and the LMW'-fraction was a mixture of LMW' (50%), LMW (20%) and two derivatives of intermediate m.w.. The HMW fraction (mw. 340 000) contained intact Aa-chains, while the molecular weight of LMW was reduced to 305 000 and that of LMW' to 270 000 due to proteolysis of the -COOH terminal end of one (LMW) or both (LMW') Aa-chains. The clottability of HMW was 98%, of LMW 92% and of LMW' about 80%. Thrombin clotting times (1 NIH U/ml) were 14", 20" and 25" resp. These differences were highly accentuated when clotting was performed with reptilase (14", 38" and 120"). Contamination with soluble fibrin was less than 2% and the contents of fibronectin and AT-III were low. No thrombin or plasmin activity was generated upon 24 hours incubation at +4 degrees C as evidenced by increased content of fibrinopeptide-A and fragment Bb-15-42 resp.

Electrophoresis, Polyacrylamide Gel↗

Thyroid gland volume and serum concentrations of thyroid hormones in chronic renal failure.

Thyroid gland volume, ultrasonically determined, and thyroid function were investigated in 40 patients with chronic renal failure (33 of these on hemodialysis) and 40 sex-, age- and weight-matched healthy controls. None had thyroid autoantibodies or a clinically detectable goiter. The median thyroid gland volume was significantly elevated in the uremic patients: 24 ml (range 8-43 ml) compared with the healthy controls 17 ml (range 10-22 ml) (p less than 0.005). The serum concentrations of thyroxine (T4), triiodothyronine (T3), free thyroxine index (FT4I) and free triiodothyronine index (FT3I) were significantly decreased in uremic subjects compared with the controls. The serum concentration of thyrotropin did not differ significantly between patients and controls. None of the thyroid function variables correlated with thyroid gland volume. In conclusion, thyroid gland volume was increased in patients with chronic renal failure. The alterations in thyroid hormone concentrations could, however, not explain this finding.

Adolescent↗