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Biomedical subjects

M Rickert

Publications and source records attributed to M Rickert.

27 records · Page 2Linked to original sources
PubMed1985

Duplication of Escherichia coli during inhibition of net phospholipid synthesis.

In Escherichia coli BB26-36, the inhibition of net phospholipid synthesis during glycerol starvation affected cell duplication in a manner that was similar in some respects to that observed during the inhibition of protein synthesis. Ongoing rounds of chromosome replication continued, and cells in the D period divided. The initiation of new rounds of chromosome replication and division of cells in the C period were inhibited. Unlike the inhibition of protein synthesis, however, the accumulation of initiation potential in dnaA and dnaC mutants at the nonpermissive temperature was not affected by the inhibition of phospholipid synthesis. Furthermore, proteins synthesized during the inhibition of phospholipid synthesis can be utilized later for division. The results are consistent with a dual requirement for protein and phospholipid synthesis for both the inauguration of new rounds of chromosome replication and the initiation of septum formation. Once initiated, both processes progress to completion independent of continuous phospholipid and protein synthesis.

Bacterial Proteins↗
PubMed1981

Comparison among patterns of macromolecular synthesis in Escherichia coli B/r at growth rates of less and more than one doubling per hour at 37 degrees C.

In Escherichia coli B/r, the relationship between the patterns of chromosome replication and of synthesis of envelope components differs at various growth rates. At growth rates greater than 1.0 doubling per h at 37 degrees C, the average mass and age at initiation of rounds of chromosome replication are similar to those at increase in incorporation of precursors into a major outer membrane protein and phosphatidylethanolamine. At growth rates less than 1.0 doubling per h at 37 degrees C the average mass and age at increase in the synthesis of these envelope components differ from those at initiation of chromosome replication. The average cell mass per chromosomal origin at initiation of rounds of chromosome replication is not a constant and varies between growth rates greater and less than 1.0 doubling per h.

Bacterial Proteins↗
PubMed1980

Cell division of cycle of Bacillus subtilis: evidence of variability in period D.

In Bacillus subtilis the deoxyribonucleic acid content and the extent of cell division during inhibition of chromosome replication increased as a function of the average cell mass, independent of the growth rate. At each growth rate, mass, deoxyribonucleic acid, and residual division varied in different cultures. The variation is consistent with a large variability in the D period. At growth rates higher than 1.5 doublings per h at 37 degrees C, the change in D accounts for the growth rate dependence of the mass and deoxyribonucleic acid content.

Bacillus subtilis↗
PubMedDate not supplied

Evolution of lesions of the labrum-ligament complex in posttraumatic anterior shoulder instability: a prospective study.

The aim of this study was to evaluate the evolution of intraarticular disease in posttraumatic shoulder instability. Ninety-one patients with posttraumatic shoulder instability were examined arthroscopically. The intraarticular disease was recorded on a special documentation sheet (containing 67 descriptive items). The patients were divided into 5 subgroups: first-time dislocation (n = 9); first or second recurrence (n = 12); 3 to 5 recurrences (n = 23); 6 or more recurrences (n = 32); and chronic subluxations (n = 15). All data were examined statistically. Each lesion was correlated with stage of evolution, age, and number of recurrences. The most frequent lesions were regrouped into "lesion families." The initial and most constant lesion was the periosteal disinsertion of the anteroinferior labrum (single lesion). The labral detachment was succeeded in a second stage by the disinsertion of the glenohumeral ligament complex (double lesion). With additional recurrences, stress mechanisms altered the detached structures through tissue damage (triple lesion). The fourth stage saw the extension of the degenerative process, which led to failure at the insertion site and destruction of the labrum-ligament complex (quadruple lesion). This study reveals that recurrences progressively damage stabilizing structures. A pathophysiological classification into 4 stages is proposed, however, that would permit a precise therapeutic strategy for arthroscopic shoulder stabilization.

Adolescent↗
PubMedDate not supplied

[Traumatic rupture of the rotator cuff in an adolescent--case report].

A traumatic rotator cuff tear is a very rare condition, especially in the adolescent. We report about a 14-year-old boy who fell onto the right arm while riding his bicycle. Immediately after the accident he described some kind of click in his right shoulder. he was referred to our institution 3 days after the trauma. The MRI showed a huge defect of the labrumligament complex including the rotator interval. Intraoperatively, we found a complete disruption of the subscapularis and supraspinatus tendons as well as of the anterior stabilizers. We performed a modified Bankart repair and a reconstruction of the ruptured rotator cuff. The patient returned to his former sports as cyclist 3 months after surgery. This case is of clinical relevance because of the traumatic disruption of an intact rotator cuff in a young patient. Not the bone but rather the tendons and ligaments were the weakest link in this situation. In cases of primary traumatic shoulder dislocation, we have to look for bony and soft-tissue damage including the rotator cuff. With the present high standards in ultrasound and MR imaging we have to keep these techniques in mind in order not to overlook this type of accompanying injury.

Adolescent↗
PubMedDate not supplied

[Migration of shoulder prosthesis as a consequence of hemi- or total arthroplasty].

BACKGROUND: Migration after shoulder arthroplasty can induce muscular dysbalance and instability of the shoulder joint. The aim of this study was to analyse the frequency, causes and consequences of secondary migration after shoulder arthroplasty. METHODS: 107 shoulder arthroplasties in patients with primary osteoarthritis (OA, n = 83) or avascular necrosis of the humeral head (AVN, n = 24), were followed clinically and radiographically over a period of 1 to 10 years. RESULTS: 17 Patients (16 %) developed secondary migration of the prosthesis. These were determined after a mean period of 33 months after shoulder arthroplasty. Patients with secondary migration of the prosthesis showed a worse function with a mean Constant score (CS) of 52.3 points in comparison to the patient group without migrated shoulder arthroplasties (62 points) (p = 0.038). In patients with total shoulder arthroplasty (TSA, n = 75), migration was observed in 13 % of cases during follow-up. Lucent lines at the glenoid were found in radiographs in 55 % of migrated shoulders and in 52 % of non-migrated shoulders (p = 0.633). The Constant score showed no significant difference between the groups (non-migrated shoulders 63 points, migrated shoulders 61 points, p > 0.5). Migration was seen in 22 % (7/32 patients) after hemiarthroplasty, however, no significant difference could be found between the respective Constant scores for migrated (47.7 points) or non-migrated (55.1 points) shoulders (p = 0.447). In patients with OA there was no significant difference in Constant score between migrated and non-migrated shoulders (p = 0.331), whereas patients with AVN showed significantly worse function after migrated shoulder arthroplasty (p = 0.007). CONCLUSION: Migration after total shoulder arthroplasty leads in the medium term neither to an increased frequency of lucent lines at the glenoid nor to a worsening of the functional score in comparison to non-migrated prosthesis. In patients with AVN, migration is accompanied by a worsening of the functional score and can consequently be regarded as a negative prognostic factor.

Arthroplasty, Replacement↗
PubMedDate not supplied

[Efficiency of a postoperative treatment after rotator cuff repair with a continuous passive motion device (CPM)].

AIM: The main objective of this study was to prove that a postoperative combined continuous passive motion (CPM) and physiotherapy treatment protocol (CPM group) can achieve 90 degrees active abduction in the shoulder joint earlier than physiotherapy alone (PT group). The indication was a complete tear of the rotator cuff. METHOD: The study was conducted under in-patient and out-patient conditions. 55 patients were included in this study. The prospective, randomized multicenter study design complies with DIN EN 540. The primary endpoint was the time span until 90 degrees active abduction was achieved by the patients. RESULTS: Patients in the CPM group reached the primary endpoint on average 12 days earlier than the control group. This difference was statistically significant (p = 0.0292). Analyzing the secondary endpoints, e. g., pain and disablement, the results in the CPM group showed again advantages of the combined treatment protocol (CPM + physiotherapy). CONCLUSION: The postoperative treatment of a total tear of the rotator cuff with a combined continuous passive motion and physiotherapy protocol provided a significantly earlier range of motion in the shoulder joint than physiotherapy alone. There was no report of CPM-related adverse effects.

Double-Blind Method↗