The learning curve for interventional cardiologists performing acute stroke interventions

Background

Endovascular treatment for acute stroke because of large vessel occlusion became the standard of care in certain clinical settings. Due to lack of trainees and specialized centers, interventional cardiologists joined multidisciplinary stroke teams, and contribute their extensive knowledge on acute cardiovascular interventions and catheter skills to optimize patient management and outcomes.

Purpose

To investigate if a learning curve exists for interventional cardiologists performing acute stroke interventions.

Methods

Consecutive patients undergoing acute endovascular stroke treatment from 07/2012 – 10/2020 at our center were reviewed. The interventional approach, lesion preparation and material selection were at the discretion of the performing cardiologist. Baseline characteristics, procedural information and in-hospital outcomes were retrospectively collected. Cases were chronologically sorted, divided into quartiles and outcomes were compared.

Results

One-hundred-thirteen patients underwent endovascular procedures for acute stroke treatment. Patients were 72.9 SD 13.3 years old, and 51.5% were female. NIHSS at baseline was 15 [12–18]. In 92% the blood flow of the anterior circulation was affected. The door to needle (DTN) time decreased over time (Q1 1:19h [range0:54–1:58] vs. Q2 0:49h [range 0:34–1:32] vs. Q3 1:13h [range 0:56–1:31] vs. Q4 0:54 [range 0:37–1:08], p=0.003), as well as the procedure duration (time of vascular access to (full) reperfusion Q1 1:24h [range 0:44–2:23] vs. Q2 0:52h [range 0:32–1:16] vs. Q3 0:49h [range 0:27–1:15] vs. 0:44h [range 0:28–1:17], p=0.014) and the use of contrast medium (Q1 103.3mL [range 75.1–147.7] vs. Q2 123.5mL [range 60.5–149.9] vs. Q3 99.8mL [range 73–132] vs. Q4 74.8 mL [range 52.4–94.6], p=0.014). A stent retriever only strategy was preferred in the early stages (Q1 42.8% vs. Q2 53.5% vs. Q3 32.1% vs. Q4 17.2%. p=0.010), whereas a stent retriever plus aspiration strategy (Q1 17.8% vs. Q2 14.2% vs. Q3 28.5% vs. Q4 50%, p=0.122) became more popular later on. The combined quality endpoint comprising of TICI IIb/III flow after the procedure, no embolization to new territories and no symptomatic intracranial bleeding was reached 84%, with no difference between groups. Vascular access site complications were low (overall 3.5%) and NIHSS prior to discharge was comparable (Q1 3 [range 1.75–7.25] vs. Q2 4.5 [range 1.75–8.25] vs. Q3 5 [range 2–8] vs. Q4 4 [range 2–7], p=0.725). In-hospital death occurred in 21 (18.5%) patients.

Conclusions

A learning curve for interventional cardiologist performing acute stroke interventions could be observed in terms of optimized management strategies such as a reduced door to needle time and procedural aspects, like decreased procedure duration and contrast medium use over time. However, the quality of care was unaffected and continuously high.

Funding Acknowledgement

Type of funding sources: None.

Regular hours vs. on-call endovascular interventions for acute stroke treatment: initial single-center experience by interventional cardiologists

Background

Endovascular treatment for acute stroke with large vessel occlusion became the mainstay therapy but remains limited due to lack of trainees and specialized centers. To offer this therapeutical option to a vast population, interventional cardiologists joined interdisciplinary stroke teams. Because of limited experience, it remains unclear if the timing of the procedure (i.e., regular hours vs. on-call time) may influence quality, time-effectiveness and outcomes.

Purpose

To investigate if the timing of the procedure (i.e., regular hours vs. on-call time) significantly influences procedural parameters and outcomes of patients undergoing acute endovascular stroke treatment.

Methods

Consecutive patients undergoing acute endovascular stroke treatment from 07/2012 – 10/2020, treated by cardiologists, were reviewed. Baseline characteristics, procedural aspects and clinical outcomes were retrospectively collected. Cases were divided into two groups, depending on the timing of the procedure: on-call time (OC, i.e., weekend days, public holidays and documented “call in” of the on-call service) vs. regular hours (RH, i.e., all other procedures) and outcomes subsequently compared.

Results

One-hundred-thirteen consecutive patients underwent endovascular treatment for acute stroke; of those 77 (68.1%) during regular hours and 36 (31.9%) during on-call time. Patients were in their early 70ies and risk factors such as arterial hypertension, diabetes mellitus, dyslipidemia and atrial fibrillation were evenly distributed. Modified Ranking Scale (mRS) at presentation was 5 in both groups and decreased to 3 at discharge. The anterior circulation was most often affected (RH: 90.9% vs. OC: 94.4%, p=0.518) and a stent retriever only strategy commonly chosen (RH: 42.8% vs. OC: 30.5%, p=0.211), followed by a combined approach of stent retriever use and aspiration (RH: 25.9% vs. OC: 27.7%, p=0.752). Door-to-needle time (RH: 0:55h IQR [0:45–1:22] vs. OC: 1:05h IQR [0:54–1:30], p=0.237) and procedure duration (RH: 0:48h IQR [0:30–1:25] vs. OC: 0:58h IQR [0:35–1:46], p=0.214) were comparable. Contrast agent use and radiation time (RH: 17.6 min IQR [11.7–29.3] vs. OC: 17.6 min IQR [12.1–33.6]) did not differ between groups, however patients in the OC group experienced a higher dose area product (RH: 4827mGy cm2 IQR [1567–14092] vs. 12727mGy cm2 [6732–18889], p<0.001). The combined quality endpoint, comprising of TICI IIb/III flow after the procedure, no embolization to new territory and no symptomatic intracranial bleeding during in hospital stay was met in 85.5% of patients in the RH group and 80.5% of the on-call group (p=0.485). Death during in-hospital stay was observed in 22% of patients in the RH group and 11.1% of the OC group (p=0.163).

Conclusions

Endovascular intervention for acute stroke treatment during on-call time is as effective and safe as if performed during regular hours but associated with a higher dose area product.

Funding Acknowledgement

Type of funding sources: None.

Giant crystals inside mitochondria of equine chondrocytes

The present study reports for the first time the presence of giant crystals in mitochondria of equine chondrocytes. These structures show dark contrast in TEM images as well as a granular substructure of regularly aligned 1-2 nm small units. Different zone axes of the crystalline structure were analysed by means of Fourier transformation of lattice-resolution TEM images proving the crystalline nature of the structure. Elemental analysis reveals a high content of nitrogen referring to protein. The outer shape of the crystals is geometrical with an up to hexagonal profile in cross sections. It is elongated, spanning a length of several micrometres through the whole cell. In some chondrocytes, several crystals were found, sometimes combined in a single mitochondrion. Crystals were preferentially aligned along the long axis of the cells, thus appearing in the same orientation as the chondrocytes in the tissue. Although no similar structures have been found in the cartilage of any other species investigated, they have been found in cartilage repair tissue formed within a mechanically stimulated equine chondrocyte construct. Crystals were mainly located in superficial regions of cartilage, especially in joint regions of well-developed superficial layers, more often in yearlings than in adult horses. These results indicate that intramitochondrial crystals are related to the high mechanical stress in the horse joint and potentially also to the increased metabolic activity of immature individuals.

First protein and peptide characterization of the tarsal adhesive secretions in the desert locust, Schistocerca gregaria, and the Madagascar hissing cockroach, Gromphadorhina portentosa

Peptides and proteins have been largely neglected in the analysis of insect tarsal adhesives. After extraction of the protein fraction of the tarsal secretion of the desert locust, Schistocerca gregaria, and Madagascar hissing cockroach, Gromphadorhina portentosa, we combined Fourier transform infrared spectroscopy (FTIR), sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) analyses for protein mass detection. In both these insects, SDS-PAGE analysis revealed several protein bands ranging from 8-190 kDa in both the tarsal secretion and the tibia control sample. Two (S. gregaria) and one (G. portentosa) protein bands exclusively occurred in the tarsal secretion and can be considered to belong to peptides and proteins specific to this secretion. MALDI-TOF analyses revealed 83 different proteins/peptides of 1-7 kDa in S. gregaria, and 48 of 1-11 kDa in G. portentosa. 59 (S. gregaria) and 27 (G. portentosa) proteins exclusively occurred in the tarsal secretion. In G. portentosa, a characteristic series of signal peaks occurred in the range of c. 10-12 kDa, each peak being approximately 160 Da apart. Such a pattern is indicative of proteins modified by glycosylation. Our approach demonstrates that extensive sampling involving considerable time and manpower to sample the adhesive fluid directly from the tarsi opens up a perspective for extracting peptides and proteins in sufficient quantities. This makes them accessible to the field of proteomics and thus to elucidate their possible function in the adhesive process.

Oligodendrogliomas: A comparison of CT and MR imaging features with histological malignancy grading in 20 cases: A pathoradiological study

Purpose: To study the pattern of contrast enhancement in MR and CT of oligodendrogliomas and to compare this with other imaging findings and with histopathological grading criteria.

Material and Methods: 20 patients with oligodendrogliomas (12 low-grade WHO II and 8 anaplastic WHO III) were reviewed. 20 complete MR investigations, 20 non-enhanced CT studies and 16 CTs after contrast enhancement were estimated blindly without knowledge of the tumour histological grades.

Results: All anaplastic oligodendrogliomas showed tumour contrast enhancement on MR and CT images. Also in 6/12 low-grade oligodendrogliomas the contrast was enhanced on MR imaging. In 5 of these, tumour calcifications were detected by CT. The remaining 6/12 WHO grade II cases showed no significant MR contrast enhancement. Of the oligodendrogliomas grade II, CT showed contrast uptake in 3 cases and no enhancement in 6, while in 3 cases postcontrast CT was not available. A comparison of contrast enhancement with tumour grade resulted in a p-value of 0.042 for MR and of 0.011 for CT. A combined statistical test of tumour grade and calcifications detected by CT compared with MR contrast enhancement showed a significant correlation ( p=0.014).

Conclusion: These data demonstrated that a clear grading of oligodendrogliomas based on the image criterion MR contrast enhancement was not possible. We suppose that, besides tumour neovascularisation, additional factors such as calcifications may disturb the blood-brain barrier.

Mobile stroke unit for diagnosis-based triage of persons with suspected stroke

BACKGROUND

In this feasibility study, we tested whether prehospital diagnostic stroke workup enables rational decision-making regarding treatment and the target hospital in persons with suspected stroke.

METHODS

A mobile stroke unit that delivers imaging (including multimodal brain imaging with CT angiography and CT perfusion), point-of-care-laboratory analysis, and neurologic expertise directly at the emergency site was analyzed for its use in prehospital diagnosis-based triage of suspected stroke patients.

RESULTS

We present 4 complementary cases with suspected stroke who underwent prehospital diagnostic workup that enabled direct diagnosis-based treatment decisions and reliable triage regarding the most appropriate medical facility for that individual, e.g., a primary hospital vs specialized centers of a tertiary hospital.

CONCLUSIONS

This preliminary report demonstrates the feasibility of prehospital diagnostic stroke workup for immediate etiology-specific decision-making regarding the necessary time-sensitive stroke treatment and the most appropriate target hospital.

[Cavernous malformations]

Cavernomas of the CNS may involve brain parenchyma as well as the spinal cord and belong to those cerebrovascular malformations that have no arteriovenous shunt and thus are generally angiographically occult. Contrary to computed tomography (CT), which is generally suited to reveal calcifications or acute bleeding, magnetic resonance imaging (MRI) enables detection of even small cavernomas. A frequently associated venous anomaly is helpful for correct diagnosis.

[Sellar tumors]

Because of the complex anatomy, examination of the sella turcica and hypophysis needs a dedicated MR sequence protocol. Not every sellar lesion is a pituitary adenoma. Thus, this review article summarizes the most frequently encountered intra-, supra-, and parasellar tumors and lesions. Differential diagnoses comprise besides adenoma among others craniopharyngioma, meningioma, glioma, germinoma, hamartoma, aneurysm, trigeminal schwannoma, pituitary carcinoma, chordoma, metastasis, infection, and empty sella. Characteristic imaging findings are presented and correlated to micro- and macro-pathology.

[Supratentorial tumors]

Magnetic resonance imaging is a routine diagnostic measure for a suspected intracerebral mass. Computed tomography is usually also indicated. Further diagnostic procedures as well as the interpretation of the findings vary depending on the tumor location. This contribution discusses the symptoms and diagnostics for supratentorial tumors separated in relation to their intra- or extracranial location. Supratentorial tumors include astrocytoma, differentiated by their circumscribed and diffuse growth, ganglioglioma, ependyoma, neurocytoma, primitive neuroectodermal tumors (PNET), oligodendroglioma, dysem-bryoplastic neuroepithelial tumors (DNET), meningoangiomatosis, pineal tumors, hamatoma, lymphoma, craniopharyngeoma and metastases. The supratentorial extracranial tumors include the choroid plexus, colloid cysts, meningeoma, infantile myofibromatosis and lipoma. The most common sub-forms, especially of astrocytoma, will also be presented.

[Spinal infections]

Regardless of the compartment involved, imaging of spinal infections and other spinal inflammatory diseases must be performed by magnetic resonance imaging (MRI). This allows early detection of changes in disk space or vertebral bodies. Associated paraspinal and epidural masses are depicted. However, in spinal cord inflammation MRI has a very limited specificity and cannot usually differentiate between the wide array of possible causes of intramedullary lesions. This article covers a spectrum of inflammatory lesions of the spinal cord.

[Stroke]

Today stroke represents a major medical and political problem in Western industrial nations. High demands need to be placed on the initial diagnostic work-up and therapeutic treatment to ensure that the patients benefit from the recent advancements achieved in diagnostic and therapeutic fields. According to the motto "time is brain" the clinical examination and imaging have to be performed within 60 min ("door to needle time") so that potential patients can be quickly treated with systemic or intra-arterial lysis. However, it should be taken into consideration that the selection of diagnostic imaging facilities depends on several factors such as infrastructure, the time remaining in the diagnostic window, and the severity of the clinical symptoms.

[Imaging of spinal tumors]

Spinal tumors are often categorized into extradural, intradural extramedullary, or intramedullary. Although this classification represents somewhat of an overgeneralization as a lesion may reside in two compartments, it still helps to characterize spinal tumors. In the intradural, extramedullary space, primary tumors, such as neurofibroma and meningioma, are relatively common. Secondary tumors or leptomeningeal enhancement also occur. In the intramedullary space, primary tumors are far more common than secondary tumors or metastases.

[Spondylitis/spondylodiscitis]

Spondylitis is an inflammation of the vertebral body. If the infection is manifested in the vertebral motor segment it is called spondylodiscitis, which can be divided into specific and nonspecific forms. It is clinically impressive that at the beginning of the disease, the patients who are quite often immunosuppressed suffer from localized, especially nocturnally exacerbated backache. The initial diagnostic work-up generally consists of clinical history, examination, laboratory tests, and (especially advanced) imaging findings. Although computed tomography still remains the most frequently used advanced imaging technique, magnetic resonance imaging is the golden standard for the diagnosis of spondylitis and spondylodiscitis.

[Skull base tumors]

Modern imaging techniques have great importance in the diagnosis and therapy of skull-base pathologies. Many of these lesions, especially in relation to their specific location, can be evaluated using CT and MR imaging. Tumors commonly found in the anterior skull base include carcinoma, rhabdomyosarcoma, esthesioneuroblastoma and meningioma. In the central cranial fossa, nasopharyngeal carcinoma, metastases, meningioma, pituitary adenoma and neurinoma have to be considered. The most common neoplasms of the posterior skull base, including the CP angle, are neurinoma, meningioma, nasopharyngeal carcinoma, chordoma and paraganglioma. One major task of imaging is the evaluation of the exact tumor extent as well as its relationship to the neighboring neurovascular structures. The purpose of this review is to recapitulate the most important anatomical landmarks of the skull base. The typical imaging findings of the most common tumors involving the skull base are also presented.

Anatomie des Kleinhirnbrückenwinkels

The cerebellopontine angle (CPA) is an anatomically complex region of the brain. In this article we describe the anatomy of the CPA cisterns, of the internal auditory canal, the topography of the cerebellum and brainstem, and the neurovascular structures of this area.

[Spinal intradural tumors]

Spinal intradural tumors are uncommon lesions but may cause significant morbidity. In establishing the differential diagnosis for a spinal lesion, location, age, and the patient's clinical presentation are important. Magnetic resonance imaging plays a central role in the visualization of spinal tumors, easily allowing tumors to be classified as extradural, intradural extramedullary, or intramedullary which is very useful in tumor characterization. We describe intradural tumors; the majority is extramedullary, with nerve sheath tumors being the most frequent. Intramedullary tumors are uncommon spinal tumors. Ependymomas and astrocytomas comprise the majority of this group. Typical imaging features of both intradural extramedullary and intramedullary tumors are described.

Behandlung der arteriosklerotischen Karotisstenose: ein �berblick

Endarterectomy for extracranial carotid stenosis has proven to be the method of choice for symptomatic patients suffering from ischemia (NASCET, ECST). The effectivity of the operation for asymptomatic stenosis seems to be likely since the publication of the first results of the ACST trial. The safety and efficiency of carotid stenting has not been proven so far and has to be evaluated in randomized trials comparing surgery and endovascular treatment. We provide an overview of the current trials and try to define the role of carotid stenting.

[Craniocerebral trauma in childhood]

This article describes typical head injuries in infants and children. In comparison with adults there are distinct differences in the etiology of trauma and in the kind of reaction of the skull and brain. In infants and children there are three different types of trauma: birth trauma, accidental and non-accidental injury. The typical injuries in these three groups are described.

Stroke im Kindesalter

About 3% of cerebral infarcts occur in children and young individuals, and pediatric stroke is even less common. Cerebral infarcts in children have different etiologies compared to adults. The common causes are described, as well as sinus venous occlusions. Cerebral veno occlusive disease is an elusive, often underdiagnosed cause of acute neurologic deterioration.

Supratentorielle Tumoren im Kindesalter

In Germany about 400 children are diagnosed of having a brain tumour each year. About half of them are located in the supratentorial region. Despite the fact, that brain tumours are the most common solid tumour in childhood, they are very heterogeneous, regarding clinical symptoms, pathology, treatment and prognosis. Imaging studies play an important role for diagnosis and follow-up.

[White matter alterations in neurodegenerative and vascular dementia]

Due to a significant overlap of the two syndromes, differentiation of degenerative dementia of the Alzheimer-type from vascular dementia may be difficult even when imaging studies are available. White matter changes occur in many patients suffering from Alzheimer's disease. Little is known about the impact of white matter changes on the course and clinical presentation of Alzheimer's disease. High sensitivity of MRI in the detection of white matter alterations may account for over-diagnosing vascular dementia. The clinical significance of white matter alterations in dementia is still a matter of debate. The article reviews current concepts about the role of white matter alterations in dementia.

Oligodendrogliomas

PURPOSE

To study the pattern of contrast enhancement in MR and CT of oligodendrogliomas and to compare this with other imaging findings and with histopathological grading criteria.

MATERIAL AND METHODS

20 patients with oligodendrogliomas (12 low-grade WHO II and 8 anaplastic WHO III) were reviewed. 20 complete MR investigations, 20 non-enhanced CT studies and 16 CTs after contrast enhancement were estimated blindly without knowledge of the tumour histological grades.

RESULTS

All anaplastic oligodendrogliomas showed tumour contrast enhancement on MR and CT images. Also in 6/12 low-grade oligodendrogliomas the contrast was enhanced on MR imaging. In 5 of these, tumour calcifications were detected by CT. The remaining 6/12 WHO grade II cases showed no significant MR contrast enhancement. Of the oligodendrogliomas grade II, CT showed contrast uptake in 3 cases and no enhancement in 6, while in 3 cases postcontrast CT was not available. A comparison of contrast enhancement with tumour grade resulted in a p-value of 0.042 for MR and of 0.011 for CT. A combined statistical test of tumour grade and calcifications detected by CT compared with MR contrast enhancement showed a significant correlation (p=0.014).

CONCLUSION

These data demonstrated that a clear grading of oligodendrogliomas based on the image criterion MR contrast enhancement was not possible. We suppose that, besides tumour neovascularisation, additional factors such as calcifications may disturb the blood-brain barrier.

[Accuracy of fluoroscopic navigation of pedicle screws. CT-based evaluation of bone screw placement]

While the advantages of C-arm navigation in computer-assisted spine surgery are obvious, the accuracy of pedicle screw placement with virtual fluoroscopy still needs to be verified. The C-arm-based ION system (Medtronic Sofamor Danek) was used to navigate pedicle screw insertion in patients undergoing spinal surgery for various conditions. In a prospective study, a total of 160 screws were inserted in the first 30 consecutive patients since introduction of the system at our institution: 54 at the thoracic spine (highest level: TH4) and 106 at the lumbar spine. Computed tomography (CT) scans were performed postoperatively by two independent radiologists to control the accuracy of screw placement at the level of the pedicles after reconstruction of axial images according to Laine et al. The comparison of the calculated accuracy rate of pedicle screw placement using virtual fluoroscopy with reported results achieved with CT-based navigation shows similar results for virtual fluoroscopy and a remarkable increase of accuracy in comparison to reports on conventional pedicle screw placement.

Lexical emotional expression across the life span: quantitative and qualitative analyses of word list generation tasks

The current study examined the effects of age and gender on emotional and nonemotional expression using an experimental word list generation (WLG) task (also referred to in the literature as verbal fluency) from the New York Emotion Battery (Borod, Welkowitz, & Obler, 1992). Subjects were 28 young ( M = 29.6 years), 28 middle-aged (M = 49.8 years), and 28 older (M = 69.9 years) healthy adults. The WLG task consists of 8 emotional (E; 3 positive and 5 negative) and 8 nonemotional (NE) categories. We developed and present here a detailed word error-type analysis that was used to evaluate the lexical output. In this study, both quantitative (amount of output and error-types) and qualitative (accuracy and intensity) analyses were used. While subjects produced more nonemotional than emotional words and more positive than negative words, the amount of error-free output and the number of errors did not change with age. An age group by error-type interaction indicated that older adults, especially men, produced more repetition errors than younger adults. The error-free output was subsequently rated for accuracy and emotional intensity. The rating data revealed that older women's overall lexical output was less accurate than that produced by younger women. Also, negative emotional words were more accurate and intense than positive emotional words. The procedures described here have implications for research assessing word list generation and emotional expression in clinical populations.

[Spinal angiography: vascular anatomy, technique and indications]

The indication for spinal angiography has to be closely set as in case of inadequate handling this procedure bares the risk of paraplegia. In unclear spinal symptoms lasting over a longer period of time, spinal vascular malformation have to be considered. Spinal vascular malformations are often reversible, especially if diagnosed early. Diagnostic methods have to include spinal angiography if other non-invasive methods do not lead to results. The main point is to consider spinal vascular malformations in unclear cases.

A rare simultaneous presentation of testicular mixed germ cell tumor with a contralateral testis torsion

We report a rare case of a 27-year-old man presenting with an acute scrotum with simultaneous occurrence of testicular tumor and contralateral torsion. Preoperative imaging demonstrated the testicular missed torsion, yet findings were equivocal with regard to the testicular tumor. On scrotal exploration the left testis was found to be ischemic due to threefold rotation. The right testis was not identifiable, being composed of numerous necrotic lesions. Frozen section suggested malignancy, hence high right orchiectomy was performed. Histologic examination of the right testis showed mixed germ cell tumor, containing all the subtypes. To our knowledge no similar case has been reported.

[Comparative static biomechanical studies of tripod surface structures of cementless endoprostheses]

AIM

While the importance of stability of endoprosthetic surface structures has been recognized for some time there is a lack of comparative surveys and assessment indices that would permit comparison and improvement of surfaces on cementless endoprostheses.

METHOD

Using separately produced, systematically mounted specimen pieces of endoprosthetic surfaces with isolated non-linked elements of varying shapes and sizes, stability parameters and stability behaviour are described. Results of tripode-structures are compared to spherical surfaces.

RESULT

These investigations show clearly that geometrical attributes, the orientation and the contact of surface elements to the endoprosthetic stem influence the stability considerably more than the size of these surface elements.

CONCLUSION

Using tripode-elements with different orientation, size and density, a differentiated formation of cementless endoprosthetic surfaces is possible.

[Cementless fixation of the endoprosthesis using trabecular, 3-dimensional interconnected surface structures]

While the principle of enlarging the surface area has been recognized and used in different ways for some time, there is often no schematic, detailed description or fundamental research. Taking a surface structure consisting of trabecular three-dimensional connecting elements, essential parameters are shown, making it clear that the flexible dynamic reaction of the effective "anchoring space" with a suitable specified shape (construction height, alignment, network) can be reproducibly shaped and used. This has led to a hip endoprosthesis with a graduated surface structure. The construction height of the trabecular structure varies, decreasing from proximal to distal.

Malignant tumour of the psoas: another cause of meralgia paraesthetica

Contrasting the more benign causes known for meralgia paraesthetica we report a case due to a malignant tumour of the psoas muscle. We discuss the use of sensory nerve conduction study and somatosensory evoked potentials of the lateral femoral cutaneous nerve as well as needle EMG and diagnostic nerve block to detect the site of the lesion along its course. This appears of major importance, as causes located above the inguinal ligament can bear a more serious prognosis than the ones below.

Effect of aging on kinetic parameters of 5 alpha-reductase in epithelium and stroma of normal and hyperplastic human prostate

Altered 5 alpha-dihydrotestosterone (DHT) metabolism and stromal-epithelial cell interactions are two factors hypothesized to explain the development of benign prostatic hyperplasia (BPH). Furthermore, the development of BPH is clearly age dependent. Therefore, we studied the age-dependent alteration of 5 alpha-reductase, the enzyme that catalyzes the irreversible conversion of testosterone to DHT in epithelium and stroma of the human prostate. For this purpose kinetic parameters [Km Vmax] of 5 alpha-reductase were determined separately in epithelium and stroma of normal prostatic tissue (NPR) from 5 and BPH tissue from 20 men, and the results were correlated with the age of the donors (15-86 yr). The mean Km in epithelium [NPR, 14.3 +/- 1.8 (+/- SE); BPH, 29.5 +/- 2.7 nmol/L] was significantly (P less than 0.0001) lower than that in stroma (NPR, 78.4 +/- 8.5; BPH, 185.8 +/- 13.6 nmol/L). The mean Vmax in epithelium [NPR, 23.8 +/- 3.9 (+/- SE); BPH, 27.9 +/- 3.0 pmol/mg protein.h] was significantly (P less than 0.0001) lower than that in stroma (NPR, 68.3 +/- 4.4; BPH, 173.8 +/- 12.2 pmol/mg protein.h). The DHT-forming index (Vmax/Km) in NPR epithelium [1.6 +/- 0.2 (+/- SE)] was significantly (P less than 0.01) higher than that in NPR stroma (0.9 +/- 0.1), while in BPH the DHT-forming index was nearly identical in epithelium (1.1 +/- 0.1) and stroma (1.0 +/- 0.1). The Km values in epithelium and stroma both correlated positively (P less than 0.01) with age, but the Vmax values correlated positively with age (P less than 0.0001) only in stroma. The DHT-forming index decreased significantly with age in epithelium (P less than 0.01), but remained constant in stroma. These results indicate that there is a nonuniform age-dependent alteration of Km and Vmax in epithelium and stroma of the human prostate independent of the presence of BPH, which might have an impact on the conversion rate of testosterone to DHT with advancing age.