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Biomedical subjects

M Richter

Publications and source records attributed to M Richter.

530 records · Page 30Linked to original sources
PubMedDate not supplied

Activation of human blood platelets induced by nocloprost, a stable prostaglandin E2 derivative.

Nocloprost, a 9 beta-chloro-16,16-dimethyl derivative of prostaglandin E2 (PGE2), belongs to the gastric cytoprotective agents that are used in the therapy of gastric ulcer. Since methylated derivatives of PGE2 are known to have proaggregatory effects the influence on platelets was studied. In platelet-rich citrated plasma, nocloprost (> 0.1 mumol/l) caused aggregation with a biphasic course at higher concentrations. Aggregation induced by nocloprost (1 mumol/l) corresponded to that induced by adenosine diphosphate (ADP) (5 mumol/l). Activation of platelets by nocloprost was accompanied by formation of thromboxane A2 and an increase in cytosolic calcium in Indo 1-loaded platelets. At 0.1 mumol/l it potentiated aggregation induced by low concentrations of ADP or adrenaline. The effect of nocloprost on platelets was blocked by iloprost, daltroban and indomethacin. PGE2, which was studied for comparison, at 0.1-1.0 mumol/l inhibited aggregation induced by 1 mumol/l nocloprost. The concentrations of nocloprost required for therapeutic use as antiulcer agent were lower by three orders of magnitude than those which induce human platelet aggregation.

Blood Coagulation↗
PubMedDate not supplied

Primary repair for posterior cruciate ligament injuries. An eight-year followup of fifty-three patients.

We reviewed 53 of 58 patients who had primary repairs of posterior cruciate ligament injuries between 1981 and 1988. Sixteen patients had isolated posterior cruciate ligament ruptures, 16 had complex injuries with capsular and collateral ligament involvement, and 21 had additional anterior cruciate ligament ruptures. Forty-six patients were treated by transosseous multiple-loop sutures and seven with bony avulsions by screw osteosynthesis. The mean follow-up time was 7.5 years (range, 3 to 12). All patients were examined subjectively (questionnaire) and objectively (clinical examination, KT-1000 arthrometer, functional testing, radiographs, and Cybex II isokinetic strength analysis). The results were graded according to the International Knee Documentation Committee evaluation form and the Lysholm score. The average Lysholm score was 82.4 (range, 40 to 100). Thirty-eight patients returned to their preinjury activities at the same intensity level. The patients' subjective assessments were normal or nearly normal in 35 patients. The posterior drawer test was negative or 1+ in 46 patients. Cybex isokinetic strength analysis revealed a decrease in quadriceps muscle strength of the involved limb by 10.5% (P < 0.01). Our data suggest that primary repair of posterior cruciate ligament ruptures provides good results after 8 years in approximately two thirds of the patients. Distal ligamentous ruptures, lack of athletic activity, and temporary olecranization correlated with poor results. Bony avulsions, midsubstance or proximal ruptures, and athletic activity correlated with good results.

Adolescent↗
PubMedDate not supplied

Prevalence of bovine herpesvirus-4 infection in cats in Central Michigan.

The gammaherpesvirus bovine herpesvirus-4 (BHV-4) has been isolated from a wide variety of animals, including lions and domestic cats. Although BHV-4 antibodies have been detected in normal cats and cats with urinary disorders, the epidemiology and pathogenic role of BHV-4 in cats is unknown. The purpose of this study was to determine the prevalence of BHV-4 antibodies and viral nucleic acid in a population of free-roaming cats. Plasma and peripheral blood leukocyte samples were collected from 52 male and 52 female free-roaming cats impounded at a regional animal control facility in Central Michigan. Plasma concentrations of BHV-4 antibodies were measured with an indirect fluorescent antibody test. Peripheral blood leukocyte DNA was isolated, and a 2-stage polymerase chain reaction with heminested primers delineating a conserved portion of the BHV-4 glycoprotein B gene homologue was used to amplify BHV-4-specific DNA sequences. BHV-4 antibodies were detected in 38 (73%) male and 23 (44%) female cats. Seropositive cats were significantly more likely to be male than female (odds ratio = 3.22; P = .007). Cell-associated viremia was detected in 17 (33%) male and 11 (21%) female cats. Of the 61 seropositive cats, 23 (38%) had a detectable viremia; only 5 (12%) seronegative cats had detectable viremia. Seropositive cats were significantly more likely to be viremic than seronegative cats (OR = 4.30: P = .009). Our results suggest that BHV-4 infection may be more widespread in certain cat populations than previously reported. Furthermore, many cats seropositive for BHV-4 antibodies have a concurrent cell-associated viremia.

Animals↗
PubMedDate not supplied

Accuracy study of computer-assisted drilling: the effect of bone density, drill bit characteristics, and use of a mechanical guide.

OBJECTIVE: This study was designed to determine the clinical relevant accuracy of CT-based navigation for drilling. DESIGN: Experimental model. SETTING: Laboratory. METHODS: Twelve drills of varying lengths and diameters were tested with 2 different set-ups. Group 1 used free-hand navigated drilling technique with foam blocks equipped with titanium target points. Group 2 (control) used a newly developed 3-dimensional measurement device equipped with titanium target points with a fixed entry for the navigated drill to minimize bending forces. One examiner performed 690 navigated drillings using solely the monitor screen for control in both groups. The difference between the planned and the actual starting and target point (up to 150 mm distance) was measured (mm). STATISTICS: Levene test and a nonpaired t test. Significance level was set as P < 0.05. RESULTS: The core accuracy of the navigation system measured with the 3-dimensional device was 0.5 mm. The mean distance from planned to actual entry points in group 1 was 1.3 (range, 0.6-3.4 mm). The mean distance between planned and actual target point was 3.4 (range, 1.7-5.8 mm). Free-hand navigated drilling showed an increased difference with increased length of the drill bits as well as with increased drilling channel for drill bits 2.5 and 3.2 mm and not for 3.5 and 4.5 mm (P < 0.05). CONCLUSIONS: The core accuracy of the navigation system is high. Compared with the navigated free-hand technique, the results suggest that drill bit deflection interferes directly with the precision. The precision is decreased when using small diameter and longer drill bits.

Bone Density↗
PubMedDate not supplied

[Antidesoxyribonuclease B-titer in persons of different ages and sex and comparative studies of antistreptolysin titers].

The antidesoxyribonuclease B reaction shows in persons of all classes of age examined a similar distribution of titres as the antistreptolysin reaction. The anti DNase B titres however are mostly lower than the titres of the antistreptolysin reaction, except in the group of children, 6 to 17 years of age, suffering frequently from latent infections of streptococci. Women in childbed showed lower anti DNase B titres than other persons of corresponding age. Among persons with anti DNase B titres higher than antistreptolysin titres predominate men.

Adolescent↗