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Biomedical subjects

A Wolf

Publications and source records attributed to A Wolf.

At least 235 records · Page 13Linked to original sources
PubMed1991

Operative management of bilateral facet dislocation.

Fifty-two patients with acute traumatic bilateral locked facets were treated at one trauma center during a 3 1/2-year period (July, 1987, to December, 1990). The patients presented with complete motor quadriplegia (34 cases), incomplete myelopathy (13 cases), or intact long-tract function (five cases). The injuries occurred at C2-3 (one patient, with intact function), C4-5 (12 patients), C5-6 (16 patients), C6-7 (19 patients), and C7-T1 (four patients). Immediate traction (with increasing weight and serial x-ray studies) and/or induction of general anesthesia and muscle relaxation reduced the dislocation in 40 patients, but 12 needed prompt operative reduction as their injuries failed to reduce within 4 hours. Stabilization was indicated for all patients, but three did not undergo surgery: two elderly patients with complete injuries (one refused surgery and one died), and one patient with multiple injuries (fusion was achieved by halo-vest immobilization for 3 months). Of the 49 patients treated operatively, 23 (44.2%) underwent surgery on the day of injury and 26 on a delayed basis (mean 8.7 days postinjury). Surgical treatment included fusion of the posterior facet to a spinous process (44 cases), an anterior Caspar plate technique (three cases), and both procedures (two cases). Of these 49 patients, three (6.1%) with complete injuries died due to an adult respiratory distress syndrome. Improvement of cord function, judged by functional grade change, was observed at discharge in 15 patients (31.9%) and in 15 (71.4%) of the 21 patients with a 1-year follow-up period. Of the 34 patients with complete myelopathy on admission, three are ambulatory after 1 year, and 13 others have gained function in at least one nerve root. It is concluded that prompt reduction (nonoperative or surgical) and internal stabilization facilitate recovery even in neurologically compromised patients, and that early operative intervention is a wiser option than conservative management. This report also documents a higher incidence of this injury without deficit (five of the 52 cases) than reported in other series.

Adult↗
PubMed1991

Anterior decompression in cervical spine trauma: does the timing of surgery affect the outcome?

To clarify the ideal timing of anterior decompression and stabilization for all patients with cervical spine trauma as well as its efficacy for patients with complete deficits, we reviewed the records of 103 consecutive patients with cervical spine trauma (50 incomplete deficits, Group A; 53 complete deficits, Group B) who underwent this procedure during a 5-year period at the Shock Trauma Center. We subdivided each group according to time of surgery: early and delayed (less than 24 and greater than 24 hours past injury, respectively). In Group A, 10 patients underwent early surgery and 40 patients underwent delayed surgery (range, 2 to 77 days past injury; mean, 13 days). One patient (2.5%) in the delayed group died. The following data refer to the early and delayed subgroups, respectively: average acute hospitalization, 20 and 22 days; patient motor score improvement (at discharge), 37.2 and 45.0%; functional grade improvement (at discharge), 5 (50.0%) and 9 (22.5%) patients. At 1-year follow-up, every patient who had had a deficit had progressed to a higher functional grade. In Group B, 35 patients underwent early surgery and 18 underwent delayed surgery (range, 2 to 45 days past injury; mean, 13 days). One patient (2.9%) in the early group died. The following data refer to the early and delayed subgroups, respectively: average acute hospitalization, 38.7 and 45.2 days (P less than 0.05); respiratory care (number of daily suction procedures), 6.0 and 9.86 (P less than 0.05); patient motor score improvement (at discharge), 3.9 and 4.5%; functional grade improvement (at discharge), 4 (11.4%) and 1 (5.6%) patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[The treatment of oligozoospermia with tamoxifen does not improve sperm quality].

As contradictory results have been obtained previously concerning the usefulness of tamoxifen in treatment of male infertility, we reevaluated its effects on 29 men presenting with idiopathic oligozoospermia. To determine whether a possible increase in sperm concentration might be correlated with an improvement of sperm quality, the hamster ovum penetration (HOP) test and the hypo-osmotic swelling (HOS) test were including as additional tests of sperm function. Patients were treated with tamoxifen (20mg/day) for 3 months. After already 4 weeks and continuing until the end of the study, tamoxifen had a significant effect (P less than 0.001) on blood levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T), and estradiol (E2). Prolactin (PRL) concentrations were not altered significantly (P greater than 0.05) after 3 months. There was no significant improvement (P greater than 0.05) of conventional semen parameters (volume, concentration, motility, morphology), and of HOP and HOS test results. Due to this lack of correlation between a rise in hormone levels and improvement of sperm quality, tamoxifen treatment of patients with idiopathic oligozoospermia is of questionable value.

Adult↗
PubMed1990

Pausing, switching and speed fluctuation of the bacterial flagellar motor and their relation to motility and chemotaxis.

Wild-type Escherichia coli and Salmonella typhimurium cells, tethered to glass by their flagella, rotate with brief intermittent pauses, the prevalence of which is decreased by attractants and increased by repellents. By attaching latex beads to filaments of a S. typhimurium mutant having straight rather than helical flagella, it was established that the flagella on free cells also pause intermittently. Pausing is therefore an intrinsic feature of the motor and not an artifact associated with tethering. In tethered cells of wild-type strains and non-chemotactic mutants defective in transducers, chemotaxis proteins, or the flagellar switch, both the classical response to chemotactic stimuli (change in direction of rotation from counterclockwise to clockwise or vice versa), and the pausing response to such stimuli, were linked together. No separate signal for pausing was found. In comparing different strains under different stimulation conditions, it was found that cells that never reversed seldom if ever paused, while cells that reversed frequently paused frequently. It is suggested that pausing is the result of futile switching events. A modified description of tumbling and chemotaxis is provided in which pausing, as well as reversal, has a role. Suppression of reversals and pauses by attractant stimuli commonly resulted in an increase in the speed of counterclockwise rotation; this may be because of suppression of pauses or reversals that are too brief to be detected. The clockwise rotation rate of unstimulated cells, which commonly was faster than their counterclockwise rate, was not further increased by repellent stimuli. The rotation rate of any given cell under any given condition was found to fluctuate on all time-scales measured. The study also revealed that some of the common repellents of E. coli and S. typhimurium slow down or stop the motor; these effects are not mediated by the chemotaxis machinery or intracellular pH.

Cell-Free System↗
PubMed1990

Dynamics of central nervous activation during motor imagination.

Central nervous processes of sensorimotor and behaviour control are prerequisites of skills and motor performance. Eight students (Ss) in sports were tested during motor imagination. They were requested to imagine their own movements when swimming over a distance of 100 m (sitting in a resting position, without any real or imitated movements). Electroencephalograms (EEG), heart rate (HR), skin conductance (SC), and respiration rate (RR) were recorded before, during and after one series of 3 periods of mental training (MT). HR, RR and SC increased during MT. The highest level of SC can be found at the beginning of the first period of imagination. Mean alpha-frequency of the EEG over the left occipital and precentral area in all Ss was higher during MT. The degree of these changes varied during the 3 imagination periods.

Brain↗
PubMed1989

[Status of the fallopian tube following pelviscopic surgery (conventional versus laser) of tubal pregnancy].

From 1984 to 1988, 136 patients with ectopic pregnancy were treated by endoscopic means. In 29 cases the fallopian tube was removed. In 107 patients conservative treatment was undertaken. The salpingotomy was performed with the endocoagulator and with scissors or using lasers. The postoperative status of the tube was controlled in 54 patients by hysterosalpingography (n = 17) or by second-look laparoscopy (n = 37). In 38 cases the patency test was positive. The incidence of postoperative adhesions was minimal after laser salpingotomy (16%). The complication rate was low (2%).

Fallopian Tube Patency Tests↗
PubMed1989

Effects of CCK-8 in combination with natural or synthetic secretin on amylase, lipase, trypsin, and chymotrypsin secretion in rats.

In the present study, we examined the interaction between CCK-8 and natural or synthetic secretin on pancreatic enzyme secretion. On anaesthetized rats, a proximal duodenal segment was continuously perfused with saline and amylase, lipase, trypsin, and chymotrypsin were determined in the perfusate. Neither during iv saline nor during iv secretin (natural or synthetic) at doses of 0.01, 0.05, or 0.1 CU/kg/h, any of the four enzymes changed significantly from basal values over a period of 100 min. Iv CCK-8 at stepwise increasing doses of 5, 10, and 20 pmol/kg/h elicited a significant increase of all four enzymes at the medium dose, with a further increase of amylase and trypsin, but not lipase and chymotrypsin at 20 pmol/kg/h. The addition of secretin at all 3 doses potentiated CCK-induced trypsin output. The effects of natural secretin were more pronounced than those of the synthetic peptide. Secretin significantly increased amylase secretion over basal at the lowest dose of CCK-8 (5 pmol/kg/h) that by itself had no effect on amylase release. Only the higher doses of natural but not synthetic secretin augmented lipase secretion during the lowest dose of CCK-8. Both forms of secretin had no further stimulatory effect on CCK-induced chymotrypsin secretion. The present data demonstrate that, first, in rats a potentiation of CCK-8-induced enzyme secretion by low doses of secretin is different for the four enzymes, which suggests a differential regulatory action of these two intestinal hormones on pancreatic enzyme release. Second, the different effects of natural secretin may represent those of contaminants suggesting that only synthetic secretin should be employed in future studies of this peptide on pancreatic enzyme secretion.

Amylases↗
PubMed1989

Organ-specific antibodies against ovary in patients with systemic lupus erythematosus.

We studied whether patients with systemic lupus erythematosus can have organ-specific antibodies directed against ovaries. With a recently developed enzyme-linked immunosorbent assay system that uses both a soluble and an extractable corpus luteum antigen fraction, we detected both IgG and IgM antibodies in the sera of patients with systemic lupus erythematosus (16 of 19, 84%). The highest levels of IgG antibodies were seen when the extractable organ fraction (ST80) was used as the antigen.

Antibodies↗
PubMed1989

Effect of lysophosphatidylcholine on atherosclerotic rabbit arteries.

We report here on the effect of an endothelium-dependent vascular smooth muscle relaxant, lysophosphatidylcholine (LPC) on rabbit aortic strips and on hemodynamic changes by LPC in atherosclerotic animals. Cyclic GMP changes induced by LPC in atherosclerotic vessels were also determined. Atherosclerosis was produced by feeding a high cholesterol and saturated fatty acid diet. LPC was injected into the left atrium and coronary flow was measured by radioactive microspheres; in vitro, relaxation of precontracted aortic strips by lysophosphatidylcholine was also recorded. LPC failed to increase coronary flow in the presence of atherosclerosis. In isolated aortic strips, dose-response curves with acetylcholine and LPC showed diminished relaxation in atherosclerotic preparations, and cyclic GMP production following LPC was reduced. The results demonstrate that vascular relaxation by LPC, together with its ability to activate guanylate cyclase is dependent on the functional and morphological integrity of the vascular wall.

Animals↗
PubMed1989

Correlation of lysophosphatidylcholine-induced vs spontaneous relaxation to cyclic GMP levels in rabbit thoracic aorta.

We demonstrated previously that 10(-5)M micellar solution of lysophosphatidylcholine (LPC) produced relaxation of rabbit thoracic aorta in a dose-dependent manner. It was also noticed that histamine (HA)-precontracted strips relaxed spontaneously in the absence of LPC. We now measured the cyclic GMP changes during these two types of relaxation. Results indicate that while LPC-induced relaxation was mediated through cyclic GMP, spontaneous relaxation was not. The vasodilating effect of LPC was not due to its interference with cellular viability by solubilizing the membrane, because repeated additions of LPC produced identical degrees of relaxation and after three consecutive additions of LPC, the strips continued to relax to the same degree with acetylcholine (Ach) demonstrating the functional integrity of the endothelium. LPC/Cholesterol dispersions (1:0.5 mole percent) relaxed the strips to the same extent as the micellar solution of LPC, while 1:1 mole percent did not. The results stress the role of cyclic GMP in LPC-induced relaxation. They further suggest that LPC/Cholesterol ratio may determine the availability of LPC and regulate LPC-mediated processes.

Animals↗
PubMed1989

[Dysgerminomas. Clinical aspects, therapy and prognosis with reference to the cooperative therapy study MAIKEI 83/86 for non-testicular germ cell tumors of the Society of Pediatric Oncology].

In comparison to other malignant germ cell tumors, dysgerminomas of the ovary show a high sensitivity to radiotherapy. According to histology and biological behaviour, dysgerminomas of the ovary are similar to testicular seminomas, which seem to be very sensitive to chemotherapy. Therefore, in the protocol for non-testicular germ cell tumors of the German Society of Pediatric Oncology (GPO) a treatment for dysgerminomas is established, in which the indication for primary tumor resection and a supplementary radiotherapy, or, in selected cases, primary chemotherapy and delayed tumor resection after the spreading, has been graded. After a median follow-up of 26 months, 17 of 18 patients were alive and disease-free, from which 3 patients with tumor progression after initial ovariectomy are in the second remission phase following relapse therapy. One patient died of tumor progression despite combined chemotherapy and irradiation. With a stratified therapy regime, fertility could be preserved with high probability in 13 of 17 patients.

Adolescent↗
PubMed1989

Calcium antagonists fail to protect mammalian spinal neurons after physical injury.

Most investigations of calcium antagonists as treatments for experimental spinal cord injury (SCI) have not demonstrated significant reduction of tissue damage or improvement in neurologic outcome. Many of these studies were prompted by reports that these agents increase blood flow to ischemic tissues. However, in vitro studies of renal and neuronal tissues subjected to an anoxic stress have shown that the calcium antagonists can confer direct protection on stressed parenchymal cells. We have used a tissue culture model of nerve cell injury to investigate whether calcium antagonists increase the probability of survival of spinal cord neurons after a defined physical trauma. Preliminary toxicity studies determined the maximum nontoxic dosages of verapamil (80 microM), nifedipine (10 microM), and chlorpromazine (10 microM) for neurons in our cultures. Preselected neurons (100-200 per study) were subjected to amputation of one primary dendrite at a distance of 100 microns from the perikaryon. Erythrosine B tests of viability conducted 24 h after lesioning failed to demonstrate that neurons injured in the presence of any one of these agents had an increased probability of survival compared to operated control neurons. Viability evaluations conducted 2 h after injury with phase contrast microscopy showed no evidence of slowed deterioration. Correction for other lesion physical parameters (lesion diameter and the extent of proximal segment retraction) also failed to reveal any increased protection by these agents. We conclude that calcium antagonists alone will not be useful for treatment of the primary injury of SCI.

Animals↗