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Biomedical subjects

R Lorenz

Publications and source records attributed to R Lorenz.

At least 19 recordsLinked to original sources
PubMed2001

Intradural and extradural spinal metastases.

Intradural spinal metastases are uncommon. The outcome of surgical treatment of intra- and extramedullary intradural metastases is considered to be poor, with rapid clinical deterioration. The question of optimal treatment remains controversial. We present an overview of the clinical outcome and surgical treatment of 220 spinal metastases carried out in our centre from 1980 to 1999, with particular emphasis on 11 intradural metastases. Clinical history, signs, surgical approach, outcome, and radiological reports were obtained by review of patient charts. Secondary spinal tumours most often originated from carcinomas of the breast, lung, kidney, gastrointestinal tract, and prostate. In 12% of cases, no primary tumour could be found. Drop metastases of intracranial pathology appeared in 3%. Intradural metastases were seen in 11 patients and formed a very heterogeneous group with predominance of melanoma, lymphoma, and medulloblastoma. Functional recovery and survival time were worse in intradural metastases than in extradural metastases, and the patients were younger. Treatment of metastases is designed to relieve pain and preserve or restore neurological function palliatively. Intradural metastases are a devastating condition with usually fatal outcome. Selected patients who undergo aggressive surgical treatment may have substantially increased survival.

Adult↗
PubMed2001

Recurrence of benign spinal neoplasms.

The outcome of surgical treatment of benign spinal neoplasms is considered to be excellent, with good improvement of neurological function. The risk of recurrence is estimated to be very low, except with subtotal resections. This retrospective study was designed to establish the course of illness, clinical outcome, and recurrence rate of benign spinal tumours. We present an overview of the clinical outcome and surgical treatment of 197 benign spinal tumours carried out in our centre from 1980 to 1999. Clinical history, signs, surgical approach, outcome, and radiological reports were obtained by reviewing patient charts. The most frequent benign tumour was meningeoma (41%), closely followed by neurinoma (33%) and neurofibroma (6.1%). Of all tumours, 79.7% were completely resected. Recurrence happened in 10.2% on an average of 4.3 years postoperatively. Only 2 patients suffered from neurofibromatosis. All neurinomas were completely resected at first operation, whereas three out of seven recurrent meningeomas and all ependymomas were classified as subtotally resected. Seventy per cent were treated by repeated surgical intervention. Benign tumours usually can be completely removed without adding to patients' neurological deficits. Benign tumours recur in 10.2% of cases, thus requiring long-term follow-up. Magnetic resonance imaging (MRI) studies are recommended up to 5 years postoperatively as a routine procedure.

Adult↗
PubMed2001

Manual stereotactic aspiration of spontaneous deep-seated intracerebral haematomas in non-comatose patients.

Manual stereotactic aspiration was used in 46 consecutive non-comatose patients with haematomas within the basal ganglia and the results were compared with those obtained in a similar group of 39 patients who were treated purely medically in another hospital. The operation was performed in the subacute stage, and in most cases three target-points were chosen on the scan with the largest expansion of the haematoma. The haematoma was manually aspirated with a syringe device in different depths in regard to the target-points, and mean proportion aspirated was 90.2%. The level of consciousness improved markedly and GCS scores after stereotactic surgery were significantly higher than those after medical treatment (p < 0.0001). Peri-ictal mortality was significantly reduced in the surgical group and with improved levels of consciousness, the patients were suitable for further rehabilitative treatment earlier. This resulted in a significantly reduced in-patient stay. Manual stereotactic aspiration of deep-seated intracerebral haematomas in the subacute stage proved to be a simple and safe method with high efficacy.

Adult↗
PubMed2001

Child abuse and neglect: a public health perspective.

Child abuse and neglect prevention are now poised at the threshold of the public health arena just as the prevention of communicable diseases and unintentional injuries once stood. The principles of public health combined with epidemiology helped eradicate smallpox. The expertise of many disciplines and the three-pronged (primary, secondary, and tertiary) prevention approach have moved the concept of unintentional injuries from "accidents will happen" to predictable and, therefore, preventable. Child abuse and neglect are now seen as epidemic in society. Through surveillance, intervention, prevention, and policy changes, the rate of child abuse and neglect can be significantly impacted in the same way that rates of unintentional injuries and communicable diseases have been reduced.

Child↗
PubMed2000

Influence of cold ischemia time, pretransplant anti-porcine antibodies, and donor/recipient size matching on hyperacute graft rejection after discordant porcine to cynomolgus kidney transplantation.

Organs transplanted between phylogenetically disparate species, such as from the pig into the primate, are subject to hyperacute rejection (HAR). This form of xenograft rejection is mediated by preformed natural antibodies and is believed to occur invariably in discordant xenografts thus leading to rapid destruction and complete thrombosis of the graft. Recent data, however, have shown that in the porcine to cynomolgus monkey setting, HAR is not inevitably seen after porcine kidney transplantation. The influence of preoperative antiporcine antibody levels in the recipient, cold ischemia time, and donor organ weight on the onset of HAR was investigated by using unmodified large white pigs (aged 3-12 weeks) as organ donors and adult cynomolgus monkeys (aged 1.5-3.5 years) as recipients. Porcine kidney xenotransplantation was performed in either a non-life-supporting model (n=7) or in a life-supporting model (n=8). In both models, no correlation was found between cold ischemia time and HAR. When preoperative anti-porcine antibody levels were investigated, a significant increase in incidence of HAR was observed in animals with elevated anti-porcine IgM (P<0.05) but not IgG levels (P=NS). Interestingly, although 5 of 12 grafts with an organ weight of less than 50 g underwent HAR, none of three grafts with a donor organ weight of more than 70 g showed signs of HAR. In addition, all three larger grafts showed intraoperative and postoperative urine production, although only in 1 (48 g) of the 12 grafts weighing less than 50 g primary graft function was observed. In one animal, a second porcine kidney (23 g) was successfully transplanted (without HAR) immediately after HAR and subsequent removal of a first porcine kidney (20 g). These results indicate that in the porcine to cynomolgus monkey setting anti-porcine IgM rather than IgG anti-porcine antibody levels seem to be of predominant importance for the induction of HAR. By increasing the donor organ size and weight the frequency of the onset of HAR can be at least reduced. This is most likely due to immunoabsorption of the recipients preformed antibodies in the porcine kidney without lethal damage for the graft.

Acute Disease↗
PubMed2000

CT-based needle marking of superficial intracranial lesions for minimal invasive neurosurgery.

A CT-based method of marking superficial intracranial lesions with a needle is presented. This form of neuronavigation can be applied in every neurosurgical centre. Owing to its rapid application it is also suitable for cases of emergency. The neurosurgical approach can be centred precisely over the lesion providing for a minimally invasive operation. The method has proved its efficacy in numerous cases of haematomas and cystic lesions.

Brain Diseases↗
PubMed2000

Pregnancy intention: how PRAMS data can inform programs and policy. Pregnancy Risk Assessment Monitoring System.

BACKGROUND: In most states, the Pregnancy Risk Assessment Monitoring System (PRAMS) is the only source for state-specific, population-based data on the prevalence of unintended pregnancy among women having a live birth. These data can be used in a variety of ways to inform state policies and programs aimed at the prevention of unintended pregnancy. OBJECTIVES: This paper highlights the programmatic and policy development activities undertaken by three states in relation to unintended pregnancy as well as the role that PRAMS data played in those efforts. RESULTS: Georgia, Oklahoma, and Washington have used PRAMS data to gain support for program initiatives directed at unintended pregnancy, to promote policies aimed at either monitoring or reducing unintended pregnancy, and to acquire additional funds for related programs, such as family planning.

Adolescent↗
PubMed2000

Decline of caries prevalence after the cessation of water fluoridation in the former East Germany.

In contrast to the anticipated increase in dental caries following the cessation of water fluoridation in the cities Chemnitz (formerly Karl-Marx-Stadt) and Plauen, a significant fall in caries prevalence was observed. This trend corresponded to the national caries decline and appeared to be a new population-wide phenomenon. Additional surveys (N=1017) carried out in the formerly-fluoridated towns of Spremberg (N=9042) and Zittau (N=6232) were carried out in order to support this unexpected epidemiological finding. Pupils from these towns, aged 8/9-, 12/13- and 15/16-years, have been examined repeatedly over the last 20 years using standardised caries-methodological procedures. While the data provided additional support for the established fact of a caries reduction brought about by the fluoridation of drinking water (48% on average), it has also provided further support for the contention that caries prevalence may continue to fall after the reduction of fluoride concentration in the water supply from about 1 ppm to below 0.2 ppm F. Caries levels for the 12-year-olds of both towns significantly decreased during the years 1993-96, following the cessation of water fluoridation. In Spremberg, DMFT fell from 2.36 to 1.45 (38.5%) and in Zittau from 2.47 to 1.96 (20.6%). These findings have therefore supported the previously observed change in the caries trend of Chemnitz and Plauen. The mean of 1.81 DMFT for the 12-year-olds, computed from data of the four towns, is the lowest observed in East Germany during the past 40 years. The causes for the changed caries trend were seen on the one hand in improvements in attitudes towards oral health behaviour and, on the other hand, to the broader availability and application of preventive measures (F-salt, F-toothpastes, fissure sealants etc.). There is, however, still no definitive explanation for the current pattern and further analysis of future caries trends in the formerly fluoridated towns would therefore seem to be necessary.

Adolescent↗
PubMed2000

Endoscopic ultrasound criteria for vascular invasion in the staging of cancer of the head of the pancreas: a blind reevaluation of videotapes.

BACKGROUND: It has been claimed in several prospective studies that endoscopic ultrasonography (EUS) is highly accurate in the locoregional staging of pancreatic cancer. However, the value of the EUS criteria for the diagnosis of vascular involvement is less well established. To totally exclude potential bias introduced by the availability of prior information, a completely blinded analysis of videotapes of patients with cancer of the pancreatic head was therefore conducted. METHODS: Videotape sequences of 75 patients with cancer of the head of the pancreas with surgical confirmation or unequivocally positive angiography demonstrating vascular invasion were reevaluated without any clinical data or information from other imaging studies. Involvement of the vascular system (portal vein with confluence, superior mesenteric vein, celiac axis) was assessed on EUS with special emphasis on EUS parameters of the tumor-vessel relationship. RESULTS: The overall sensitivity and specificity of EUS in the diagnosis of venous invasion were 43% and 91%, respectively, when using predetermined parameters (visualization of tumor in the lumen, complete obstruction, or collateral vessels). If the parameter "irregular tumor-vessel relationship" had been added to these criteria, the sensitivity would have risen to 62%, but the specificity would have fallen to 79%. The only vascular system that could be properly visualized by EUS was the portal vein/confluence area. The positive and negative predictive values for the single parameters chosen to diagnose portal venous involvement were as follows: 42% and 33% for irregular tumor-vessel relationship, 36% and 34% for visualization of tumor in the vascular lumen, 80% and 28% for complete vascular obstruction, and 88% and 18% for collateral vessels. CONCLUSIONS: In a completely blinded evaluation of the EUS diagnosis of vascular invasion by cancer of the head of the pancreas it was not possible to find suitable morphologic parameters with clinically useful sensitivity and specificity values (over 80%).

Adult↗
PubMed2000

Modern imaging methods versus clinical assessment in the evaluation of hospital in-patients with suspected pancreatic disease.

OBJECTIVE: Various modern imaging procedures such as endoscopic retrograde cholangiopancreatography (ERCP), computed tomography (CT), and endoscopic ultrasonography (EUS) have been shown to be highly accurate in the diagnosis of specific disorders of the pancreas. However, prior information often causes bias in the interpretation of these results. Little information is available concerning the value of these examinations in the primary and differential diagnosis of suspected pancreatic disease-particularly in comparison with clinical evaluation, including laboratory tests and transabdominal ultrasound (TUS). METHODS: Clinical and imaging information (EUS, ERCP, and CT) was collected for 184 inpatients who were referred over a 5-yr period for evaluation of suspected pancreatic disease. On the basis of patient history, laboratory tests, and the results of routine TUS, one gastroenterologist, who was unaware of any of the other procedures or the final diagnosis, made a presumptive clinical diagnosis. CT and ERCP images and EUS videotapes were then analyzed by three different and independent examiners, who had the same clinical information except for the TUS results, but were completely blinded to the results of the other examinations and the patients' diagnoses. The final diagnoses were obtained by surgery, histology, and cytology, plus a follow-up of at least 1 yr (mean 35 months) in all noncancer cases. RESULTS: The final diagnoses were: normal pancreas (n = 36), chronic pancreatitis without a focal inflammatory mass (n = 53) or with a focal inflammatory mass (n = 18), and pancreatic malignancy (n = 77). Clinical evaluation, including ultrasonography, achieved a sensitivity for pancreatic disease of 94% but a specificity of only 35%. The figures for the sensitivity and specificity of the three imaging procedures were 93% and 94%, respectively, for EUS; 89% and 92% for ERCP; and 91% and 78% for CT (p < 0.05 for the specificity of clinical assessment vs all three imaging tests, p > 0.05 for comparison of the three imaging procedures). In the differential diagnosis between cancer and chronic pancreatitis as well as between malignant and inflammatory tumors, there was no difference among clinical assessment and the three imaging tests. CONCLUSIONS: In a group of patients with a high suspicion of pancreatic disease, little additional sensitivity in the diagnosis of pancreatic disease is provided by sophisticated imaging procedures such as EUS, ERCP, and CT, in comparison with clinical assessment including laboratory values and TUS. However, the specificity can be substantially improved. To confirm the diagnosis, one of the three examinations is needed, depending on the suspected disease and local expertise. The imaging procedures should be performed in a stepwise fashion for specific purposes, such as exclusion of pancreatic disease and the planning of treatment in chronic pancreatitis and pancreatic cancer.

Adolescent↗
PubMed2000

Long term follow up after perimesencephalic subarachnoid haemorrhage.

OBJECTIVES: To evaluate the long term sequelae of perimesencephalic subarachnoid haemorrhage (PMSAH). METHODS: Twenty one consecutive patients were studied. All patients were examined by CT, angiography, MRI, multimodal evoked potentials, and transcranial Doppler sonography. All relevant clinical data during hospital stay and outcome at discharge were obtained by reviewing the charts. Long term follow up was evaluated by reviewing the outpatient files and dedicated outpatient review. Patients were specifically questioned about their perceived recovery, residual complaints, and present occupational status. RESULTS: Apart from the initial CT confirming the diagnosis of PMSAH all other examinations disclosed no abnormalities. None of the patients developed any complications during hospital stay, and all patients were discharged in good clinical condition and without neurological deficits. At long term follow up 62% of the patients had residual complaints consisting of headaches, irritability, depression, forgetfulness, weariness, and diminished endurance. Apart from four patients who had already retired before the PMSAH, only seven of the remaining 17 patients (41%) returned to their previous occupation, whereas nine patients (53%) retired from work and one man became unemployed. One patient had a recurrence of PMSAH 31 months after the first event. CONCLUSION: PMSAH can have considerable long term psychosocial sequelae, and may also recur. Prognosis may not be as good as previously reported.

Adult↗
PubMed2000

Selective mobilization of CD14(+)CD16(+) monocytes by exercise.

Strenuous, anaerobic exercise leads to an increase of leukocytes that are mobilized from the marginal pool. We have analyzed in human peripheral blood the effect of exercise on the number of CD14(+)CD16(+) monocytes as determined by two-color immunofluorescence and flow cytometry. We show herein that this type of monocyte responds with a dramatic up to 4.8-fold increase. Mobilization does not occur after 1 min at 100 or 200 W but 1 min at 400 W leads to a twofold increase of the CD14(+)CD16(+) monocytes immediately after exercise. The numbers remain high at 5 min and gradually decrease to reach the initial level at 20 min postexercise. After 20 min of rest, the CD14(+)CD16(+) monocytes can be mobilized again by a second exercise. The CD14(+)CD16(+) monocytes appear to be mobilized from the marginal pool where they preferentially home because of a higher expression of adhesion molecules like CD11d and very late antigen-4. Exercise goes along with an increase of catecholamines, and mobilization of the CD14(+)CD16(+) monocytes can be substantially reduced by treatment of donors with the beta-adrenergic receptor blocker propranolol. Mobilization of CD14(+)CD16(+) monocytes by a catecholamine-dependent mechanism may contribute to the increase of these cells in various clinical conditions.

Administration, Topical↗
PubMed2000

Utility of a brief self-efficacy scale in clinical training program evaluation.

Self-efficacy is often studied as a predictor of professional practice behaviors or as an outcome of clinical training, using brief scales with little validation. This study examines the utility of a brief self-efficacy scale in the evaluation of a clinical training program. Subjects were 119 registered dietitians who participated in diabetes training. Hypothesized relationships between self-efficacy ratings and indices of skill mastery, participation in training, and subsequent practice change were examined. Self-efficacy ratings after training correlated significantly with relevant prior experience (r = .4 and .29, p < .01) but not total experience and with knowledge post-test score (r = .21, p < .02). Self-efficacy for all 12 program objectives increased significantly after training. Post-training self-efficacy for two program objectives correlated significantly with self-reported successful practice changes related to those objectives (r = .4, p < .04 and r = .51, p < .01). The data suggest that brief self-efficacy assessments can contribute meaningfully to clinical training program evaluation.

Analysis of Variance↗
PubMed1999

Performance, patient acceptance, appropriateness of indications and potential influence on outcome of EUS: a prospective study in 397 consecutive patients.

BACKGROUND: Although there is a large body of data on the accuracy of endoscopic ultrasonography (EUS) in the diagnosis and staging of various gastroenterological disorders, little has been published on the influence of EUS in the management of patients. Data on the performance of EUS and patient acceptance are also sparse. METHODS: During a 10-month period, all consecutive EUS examinations were categorized by the examiner according to the appropriateness of the indications. Prior examinations, performance of EUS (duration, premedication, complications), and patient acceptance (assessed using a questionnaire by an independent investigator) were recorded. A mean of 2 months after the procedure, referring physicians were asked about the extent to which the EUS results had influenced their further diagnostic and therapeutic approach. RESULTS: A total of 397 patients were included; they were referred for EUS after a mean of 1. 8 specific tests had been performed. The appropriateness of the indications for EUS was categorized as "classic," "useful," and "potentially useful" (categories 1 to 3) in 81% of cases. The referring physicians replied that EUS had provided useful additional information in 55% of cases; the EUS findings prompted further tests in 22% and made further examinations unnecessary in 30%. A change in therapy was believed to be directly due to EUS in only 6% of cases. The duration of the EUS examinations ranged from a mean of 8.1 minutes (esophageal indications) to 18.9 minutes (biliary indications). There were no complications. In patients who were able to remember the EUS examination (42%), 90% found it tolerable, and 83% of all the patients interviewed were willing to have the examination repeated with the same level of sedation. CONCLUSIONS: EUS is a safe examination that can be carried out within a reasonable time frame by experienced examiners and without significant patient discomfort when performed under conscious sedation. With regard to patient management, EUS mainly influences further diagnostic tests.

Adolescent↗
PubMed1999

Lipid treatment of inflammatory bowel disease.

The aetiology of inflammatory bowel disease remains unclear. Local mediators such as arachidonic acid metabolites and peptide mediators (cytokines) appear to contribute to the disease process. The successful administration of neutralizing antibodies against TNF-alpha has confirmed a pathophysiological role for this cytokine in Crohn's disease. Established therapy of inflammatory bowel disease with 5-aminosalicylic acid compounds has been shown to reduce local leukotriene B4 formation by inhibiting lipoxygenases. This therapeutic mechanism formed one rationale for examining the effect of n-3 fatty acids, which also inhibit leukotriene B4 formation, on the course of these diseases. In the first study, published in 1989, we found no beneficial effects of n-3 fatty acids in patients with Crohn's disease; however, there was clinical improvement, just falling short of significance, in patients with ulcerative colitis. Since then two uncontrolled and five controlled studies have further investigated the therapeutic effect of n-3 fatty acids in patients with ulcerative colitis. The size of the patient population in the controlled studies ranged from 10 to 96 patients in the largest study. Two of these studies showed a significant improvement in clinical activity and a steroid-sparing effect, respectively. Another study found only a trend towards improvement and one trial, which also included a treatment group receiving evening primrose oil, found no beneficial effect in the 16 patients receiving n-3 fatty acids. A large, 2 year trial of n-3 fatty acids in patients with ulcerative colitis off steroids, which was recently completed at the Universities of Munich and Mainz, showed a delay of the first episode of relapse, but no reduction in the cumulative relapse rate at 2 years. Controversial results have been published for Crohn's disease. A new enteric-coated formulation reportedly increased the proportion of patients in remission where as another trial using a conventional preparation found no significant effect.

Colitis, Ulcerative↗