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Biomedical subjects

P Kremer

Publications and source records attributed to P Kremer.

At least 19 recordsLinked to original sources

[Prehospital management of spinal cord injuries].

In both the United States and Europe about 10,000 patients suffer from spinal cord injury (SCI) each year and 20% die before being admitted to hospital. Prehospital management of SCI is very important since 25% of SCI damage may occur after the initial event. Emergency treatment includes examination of the patient, spinal immobilization, careful airway management, cardiovascular stabilization (maintenance of mean arterial blood pressure above 90 mmHg) and glucose levels within the normal range. From an evidence-based point of view, it is still not known whether additional specific therapy is useful and studies have not convincingly demonstrated that methylprednisolone (MPS) or other substances have clinically important benefits. Recently published statements from the US do not support the therapeutic use of MPS in patients suffering from SCI in the prehospital setting. Moreover, it is not known whether hypothermia or any other pharmacological interventions have beneficial effects. Networks for clinical studies in SCI patients should be established as a basic requirement for further improvement in outcome in these patients.

Blood Volume↗

Intramedullary subependymoma of the lower spinal cord.

A 22-year-old woman developed an increasing distal paraparesis, which resulted in a severe ataxic gait. MRI demonstrated a very large intramedullary tumour mass from D11 to L2, which could not be identified as one of the common neoplastic diseases of the spinal cord. The tumour was removed completely and the diagnosis of subependymoma confirmed. With respect to our patient and to the limited reports in the literature, we describe some typical features that may help in the diagnostic and preoperative assessment of this very rare spinal cord tumour.

Adult↗

Magnetic resonance imaging after transsphenoidal surgery of clinically non-functional pituitary macroadenomas and its impact on detecting residual adenoma.

BACKGROUND AND PURPOSE: In clinically non-functional pituitary macroadenomas, prospective follow-up magnetic resonance imaging (MRI) was conducted after transsphenoidal surgery both to study the changes of the sellar contents at the post-operative site over time and to assess the amount of residual adenoma tissue. METHODS: A total of 50 patients with clinically non-functional pituitary macroadenomas were treated by transsphenoidal tumour resection and were examined by MRI before and directly after surgery (early MR) and 3 months (intermediate MR) and 1 year after surgery (late MR). Changes in the sellar contents over time and the degree of tumour excision were studied on T1-weighted enhanced and unenhanced scans. All patients underwent complete neuro-ophthalmological and endocrinological assessments before and 3 months after surgery. For the interpretation of the post-operative images the results of the endocrinological examinations after surgery were also taken into account. RESULTS: The maximum size of tumour extension on coronal T1-weighted images ranged from 1.2 cm to 5.0 cm (mean 2.3 cm). Despite tumour resection, early post-operative images still showed a persistent mass in the sella in 83% that was usually caused by post-operative haemorrhage, fluid collection and implanted fat material. However, rapid improvement in visual symptoms was noted in 89%. Changes in the sellar region at the early post-operative site markedly hindered the interpretation of MR images for detecting residual tumour tissue, which was suspected in half of the patients (1 intrasellar, 13 suprasellar, and 11 parasellar). Regression of the post-operative mass in the sella was present 3 months after surgery, resulting in a 50% change in the volume of the coronal sellar extension, which also improved the reliability in interpreting the post-operative MR images. On the intermediate MR images residual tumour tissue was detected in 30% of the patients (4 intrasellar, 2 suprasellar and 9 parasellar). Because the suprasellar mass descended over time, an increasing rate of tumour remnant within the sella was seen 3 months following surgery. Before surgery the pituitary gland was visible superiorly or posterosuperiorly to the macroadenomas in 35 patients. However, at the early post-operative site the remaining gland was only visible in 12 patients. Under the condition that endocrinological function tests confirmed adequate hormonal function, the remaining gland was detectable by MRI in 36 patients 3 months after surgery. CONCLUSION: Delayed regression of the sellar contents after transsphenoidal surgery of pituitary macroadenomas was demonstrated by this prospective MR study. Owing to the changes at the post-operative site, it was difficult to interpret early post-operative images and detect residual adenoma tissue. With respect to the delayed regression of the sellar contents, the interpretation of post-operative images for detection of residual adenoma was improved 3 months after surgery. At this time, residual adenoma tissue was found in 30% of clinically non-functional macroadenomas, mostly at the parasellar and, after descent from the suprasellar space, at the intrasellar site.

Adenoma↗

Adult hypophosphatasia. Current aspects.

Hypophosphatasia is an inborn metabolic disorder in which abnormally low levels of the enzyme nonspecific alkaline phosphatase result in defective skeletal and dental mineralization (rickets, fractures, dental abnormalities) and in accumulation of the enzyme substrates (phosphoethanolamine, pyridoxal-5'phosphate and inorganic pyrophosphate). The build-up of inorganic pyrophosphate promotes the development of articular chondrocalcinosis. There are several forms of hypophosphatasia, with wide variations in severity. We report the case of a 53-year-old man with typical manifestations of moderate adulthood hypophosphatasia. Investigations in his family found the disease in a sister and two children. He had two autosomal mutations, which were transmitted recessively. Several mutations of the alkaline phosphatase gene have been identified. The genotype is correlated with the phenotype: some mutations are associated with milder forms and others with more severe forms of the disease.

Age of Onset↗

Laser-induced fluorescence detection of malignant gliomas using fluorescein-labeled serum albumin: experimental and preliminary clinical results.

To delineate the tumor margins of malignant gliomas laser-induced fluorescence detection technique was applied using 5-aminofluorescein-albumin as the fluorescent dye. The 5-aminofluorescein was linked to serum albumin (= AFlc-SA) as a cumulative protein label using residualizing markers. In a C6-glioma model the biodistribution and pharmacokinetics of the injected dye were investigated by labeling the protein conjugate with 111In-DTPA. Twenty-four hours after intravenous injection of the dye, fluorescence was activated by an argon laser and inspected in the C6-gliomas. Histological examinations were performed to compare the microscopic margins of the fluorescence-stained tumors with hematoxylin/eosin. The tumor uptake 24 h after dye injection was 23-fold higher than in the surrounding brain. Fluorescence inspection under laser activation demonstrated clearly stained and sharply demarcated tumors. The microscopic borders of the tumors corresponded exactly with the fluorescence, also demonstrating intracellular tumor uptake of the dye. In a preliminary study, three patients with malignant gliomas were operated using laser-induced fluorescence detection technique after injection of AFlc-SA. In all patients, the borders of the malignant gliomas were clearly stained by AFlc-SA during surgery. Laser-induced fluorescence imaging using the albumin conjugate AFlc-SA may be a promising method for delineating tumor margins which are hard to detect under the operating microscope alone.

Animals↗

Clinical outcome of patients with and without renal impairment undergoing a minimally invasive LIMA-to-LAD bypass operation.

PURPOSE: Patients with renal impairment undergoing conventional coronary artery bypass grafting (CABG) have a significant risk of postoperative deterioration of kidney function. We investigated the outcome of patients with and without renal impairment treated by off-pump coronary artery surgery. METHODS: From January 1997 until January 2000, 158 consecutive patients (mean age 63 +/- 9.8 years, 126 male, 32 female) underwent minimally LIMA-to-LAD bypass operations. The patients were divided into three groups: group I patients (n = 133) had a preoperative creatinine of < 1.3 mg/dL, group II patients (n = 21) had a creatinine of > 1.3 mg/dL, and patients of group III (n = 4) required chronic dialysis due to terminal kidney dysfunction. Monitoring of the blood creatinine was performed during the entire hospital stay. A postoperative angiogram was performed in 113 of the 158 patients. RESULTS: All operations were performed without intraoperative complications. Postoperative angiograms revealed a patent LIMA-to-LAD bypass in all but one patient, who demonstrated a dissection of the left internal mammary artery (LIMA) graft. Mean creatinine value on admission was 1.0 +/- 0.1 mg/dL in group I and 2.7 +/- 1.9 mg/dL in group II. The maximal postoperative creatinine value was 1.1 +/- 0.4 mg/dL in group I and 2.9 +/- 2.7 mg/dL in group II. Neither hemofiltration nor hemodialysis was necessary in any patient of group I or group II during the postoperative course. CONCLUSION: Minimally invasive LIMA-to-LAD bypass is a safe and effective procedure with low morbidity and no mortality in the first 158 patients. Preoperative renal impairment had no adverse effect on outcome or residual kidney function. Thus, higher doses of diuretics and hemofiltration/dialysis were not used, resulting in a cost reduction. Therefore, this approach may be worthwhile to consider in patients with significant renal impairment who have to undergo CABG.

Aged↗

The scientific history of hydrocephalus and its treatment.

Hydrocephalus cases were regularly described by Hippocrates, Galen, and early and medieval Arabian physicians, who believed that this disease was caused by an extracerebral accumulation of water. Operative procedures used in ancient times are neither proven by skull findings today nor clearly reported in the literature. Evacuation of superficial intracranial fluid in hydrocephalic children was first described in detail in the tenth century by Abulkassim Al Zahrawi. In 1744, LeCat published findings on a ventricular puncture. Effective therapy required aseptic surgery as well as pathophysiological knowledge--both unavailable before the late nineteenth century. In 1881, a few years after the landmark study of Key and Retzius, Wernicke inaugurated sterile ventricular puncture and external CSF drainage. These were followed in 1891 by serial lumbar punctures (Quincke) and, in 1893, by the first permanent ventriculo-subarachnoid-subgaleal shunt (Mikulicz), which was simultaneously a ventriculostomy and a drainage into an extrathecal low pressure compartment. Between 1898 and 1925, lumboperitoneal, and ventriculoperitoneal, -venous, -pleural, and -ureteral shunts were invented, but these had a high failure rate due to insufficient implant materials in most cases. Ventriculostomy without implants (Anton 1908), with implants, and plexus coagulation initially had a very high operative mortality and were seldom successful in the long term, but gradually improved over the next decades. In 1949, Nulsen and Spitz implanted a shunt successfully into the caval vein with a ball valve. Between 1955 and 1960, four independent groups invented distal slit, proximal slit, and diaphragm valves almost simultaneously. Around 1960, the combined invention of artificial valves and silicone led to a worldwide therapeutic breakthrough. After the first generation of simple differential pressure valves, which are unable to drain physiologically in all body positions, a second generation of adjustable, autoregulating, antisiphon, and gravitational valves was developed, but their use is limited due to economical restrictions and still unsolved technical problems. At the moment, at least 127 different designs are available, with historical models and prototypes bringing the number to 190 valves, but most of these are only clones. In the 1990s, there has been a renaissance of endoscopic ventriculostomy, which is widely accepted as the method of first choice in adult patients with aquired or late-onset, occlusive hydrocephalus; in other cases the preference remains controversial. Both new methods, the second generation of valves as well as ventriculostomy, show massive deficits in evaluation. There is only one randomized study and no long-term evaluation.

Animals↗

An argon-dye laser system for photodynamic therapy and diagnosis.

An argon-dye laser system for the clinical application of photodynamic therapy and photodynamic diagnosis is presented. Two out-patient treatment rooms and three operating theaters are served by an argon-dye laser system which can be accessed by remote-control from each treatment room. The argon-dye laser offers a wide range of light wavelengths with sufficient energy for all kinds of photosensitizers and fluorescent substances. This report presents our experiences with the first remote-controlled laser configuration which is being used routinely in clinical practice for photodynamic therapy and photodynamic diagnosis.

Ambulatory Care↗

Extradural spinal hemangioblastomas: report of two cases.

Two cases of predominantly extraspinally extra- and intradural spinal cord hemangioblastomas in two patients each with and without von Hippel-Lindau-disease are reported. Preoperative MRI and angiographic findings are presented and the differential diagnosis is discussed. The surgical procedure is described and the literature of hemangioblastomas in this rare localization is reviewed. Improvements in both radiologic diagnosis and microsurgical techniques, and consequent screening programs will enhance life expectancy in patients afflicted with von Hippel-Lindau disease.

Adult↗

HLA DRB1* alleles in rheumatoid nodulosis: a comparative study with rheumatoid arthritis with and without nodules.

Rheumatoid nodulosis (RN) is a rare condition associating rheumatoid nodules, episodes of arthritis, cystic bone lesions and, generally, positive rheumatoid factors (RF). It is considered a benign variant of rheumatoid arthritis (RA). In this study, we determined the HLA DRB1* alleles of our RN patients and compared the distribution of these alleles to those of 74 healthy controls and 104 RA patients with and without nodules. Four RN patients were observed. All had subcutaneous nodules and RF were negative in three patients. Of the 104 RA patients, 18 had nodules (nodRA). Systemic manifestation (including vasculitis, peripheral neuropathy or lung involvement) were found in seven of these nodRA cases (33.8%) and most had positive RF and erosive changes on X-rays. Only one RN patient had a RA-associated allele (DRB1*0101). The frequencies of the HLA DRB1* alleles encompassing the "rheumatoid" shared epitope were similar to those of other RA series: *0101, 34.6% (P = 0.03 compared with controls); *0401, 26.9% (P < 0.0001); *0404, 12.5% (P = 0.04); *0405, 4.8% (P = 0.8); *1001, 8.6% (P = 0.5). Of the nodRA and seronegative RA patients, 77.7% and 53.3%, respectively, presented the shared epitope. Thus, there was a tendency to decreased expression of the RA-associated alleles in RN (25%) compared with nodRA and seronegative RA patients. This study is restricted by the small number of tested RN patients, but the results suggest that the RA-associated alleles are poorly expressed in RN.

Adult↗

Beating heart operations including hybrid revascularization: initial experiences.

BACKGROUND: The outcome of patients (n = 45) with coronary one- to three-vessel disease undergoing beating heart operations using a recently developed stabilizing device was investigated. METHODS: Left internal mammary artery-to-left anterior descending coronary artery (LIMA-to-LAD) revascularization was carried out alone (n = 31) or as hybrid procedure in combination with a balloon angioplasty (n = 14). RESULTS: All 45 patients underwent a successful LIMA-to-LAD procedure without intraoperative complication during a 21 +/- 8-minute (range, 10 to 53 minutes) LAD occlusion time. In 14 hybrid procedures a total of 19 stenoses including 3 left main stenoses were treated successfully by percutaneous transluminal coronary angioplasty and stenting. The postoperative courses were uneventful with the exception of two surgical reexplorations necessitated by bleeding. No worsening of renal, neurologic, or respiratory functions occurred in any patient. In the group having a single LIMA-to-LAD procedure, early postoperative coronary angiograms (22 of 31) showed a patent LIMA graft and excellent anastomosis; this was also true in 4 patients 12 months after operation as shown in angiograms. All patients undergoing hybrid revascularization demonstrated a patent LIMA-to-LAD anastomosis; in 1 patient there was a dissection in the midlevel of the LIMA, which was stented successfully. The 6-month follow-up angiograms in 7 of 14 patients revealed open LIMA bypass grafts in all patients except 1, who was stented because of dissection. CONCLUSIONS: These data indicate that a beating heart operation including hybrid revascularization is safe and effective in selected patients with coronary one- to three-vessel disease including left main stenosis. This approach may be especially advantageous in comparison with conventional coronary artery bypass grafting in patients with severe concomitant disease.

Adult↗

MR enhancement of the internal auditory canal induced by tissue implant after resection of acoustic neurinoma.

PURPOSE: We studied intrameatal changes in MR enhancement induced by free-tissue implant over time after surgery for acoustic neurinoma. METHODS: Twenty-one patients were examined by MR imaging after suboccipital resection of an acoustic neurinoma. Precontrast and postcontrast MR images were obtained within 3 days after surgery (early MR images), then 6 weeks (intermediate MR images) and 6 months (late MR images) after surgery. A muscle graft as a free-tissue implant was used within the internal auditory canal in 18 of the 21 patients to seal pneumatic cells of the petrosal bone inadvertently opened and to prevent leakage of cerebrospinal fluid. RESULTS: On the early MR images, only minimal leptomeningeal or perineural enhancement was seen in 16 patients. There was no sign of residual tumor; however, enhancement increased and changed from linear to nodular on the intermediate MR images in 16 of the 18 cases in which a muscle graft had been used during surgery, mimicking a small intrameatal tumor. This nodular enhancement was still visible on the late MR images in 13 of the 16 cases. CONCLUSION: Nodular MR enhancement within the internal auditory canal a few weeks to months after surgery for acoustic neurinoma may be induced by packing material and should be considered when interpreting postoperative MR images.

Adult↗

MR imaging of residual tumor tissue after transsphenoidal surgery of hormone-inactive pituitary macroadenomas: a prospective study.

22 patients were examined by magnetic resonance (MR) imaging before and after transsphenoidal surgery of hormone-inactive pituitary macroadenomas to evaluate for tumor removal. MR imaging was performed without and with gadolinium-DTPA before the operation and 3 months after. In all cases a suprasellar tumor extension was found preoperatively, in 9 cases with an additional parasellar, in 2 cases with an additional retrosellar extension (average diameter 2.5 cm). In 7 cases complete tumor removal was shown by postoperative MR, but in 11 cases residual tumor tissue was found (4 x suprasellar, 5 x parasellar, 2 x retrosellar). In 4 patients postoperative MR could not clearly differentiate residual tumor from scar formation. Although in cases of residual tumor follow-up MR imaging was performed over a period of two years, residual tumor volumes did not appear to change. This study demonstrates that MR imaging is highly sensitive for evaluating residual tumor tissue after transsphenoidal surgery of hormone-inactive macroadenomas.

Adenoma↗

Sarcoidosis and spondylarthropathy. Three case-reports.

Coexistent sarcoidosis and seronegative spondylarthropathy have rarely been reported. We add three new cases to the nine previously published. Two men and one woman with sarcoidosis met Amor's criteria for spondylarthropathy. The diagnosis of sarcoidosis was based on histologic findings in two cases and on roentgenographic and laboratory test findings in one case. The features of each of the two diseases were unremarkable. The two diagnoses were confirmed at about the same time. Osteoarticular manifestations of sarcoidosis are reviewed. Our case-reports illustrate the diagnostic difficulties raised by discovery of sacroiliitis in a patient with sarcoidosis: sarcoid osteitis, infection, or a spondyloarthropathy can be the cause of the sacroiliac lesions. Moreover, the pelvic and spinal manifestations of sarcoidosis can mimick a spondylarthropathy. Coexistence of sarcoidosis and spondylarthropathy is probably due to chance, since there are no shared predisposing genetic factors and the number of reported cases is small.

Aged↗

Proximal paraparesis following spinal anesthesia.

A 70-year-old man with prostatic cancer extending to the urinary bladder underwent transurethral resection of the bladder neck under spinal anesthesia and developed weakness of the proximal lower limbs a few hours after the procedure. The weakness persisted for several months. Because there were no local surgical complications (hematoma, infectious epiduritis, abscess) or bone metastases responsible for nerve root or spinal cord compression, a causal relation between the neurologic deficit and the spinal anesthesia was considered likely. Neurologic deficits are uncommon after spinal anesthesia and can be produced by complications of the surgical procedure (direct nerve injury, hematoma, abscess), arachnoiditis, neurotoxicity of disinfectants or of preservatives added to solutions of anesthetic drugs, or spinal cord ischemia. Precipitating factors for spinal cord ischemia include faulty patient position during the procedure, intraoperative arterial hypotension and injection of vasoconstricting agents.

Aged↗