Optical and thermal modeling of an optrode microdevice for infrared neural stimulation.

Infrared neural stimulation is a promising medical technique using pulsed infrared light for generating temperature-controlled firing of neurons. A combined optical and thermal model of a stimulating microtool-or so-called optrode-has been developed to investigate the amount, the spatial distribution, and the temporal behavior of the thermal excitation. Ray tracing and Fourier optics were used to describe the propagation and scattering of light in the optrode, and the finite element method was applied to model heat transfer. The scattered intensity distribution profiles were calculated based on measured surface roughness of the device and were integrated into the ray optics model. As a validation of the optical model, the simulated and measured values of the light efficiency of the microoptical system are compared. The temperature rise of the brain tissue during the infrared stimulation was estimated using the combined model. Using 30 mW total power and a single 100 ms pulse, the excitation resulted in a temperature rise of 3°C of the brain tissue. The spatial and temporal distributions of the tissue temperature are discussed in the paper. The proposed combined model is an efficient tool for the investigation and optimization of the stimulation process and for further development of the optrode configuration.

Simulation of small- and wide-angle scattering properties of glass-bead retroreflectors.

Retroreflective materials are extensively used as traffic signs and security patterns. These goods are often realized by spherical glass-beads attached to some reflective substrate. New applications, especially 3D projection, require the precise evaluation and design of the characteristics of light backscattered from retroreflective screens. Simulation of such materials is not straightforward due to the different optical processes taking place: direct retroreflection involving small-angle diffraction effects, and multiple scattering resulting in wide-angle diffuse light. We propose a new complex method to describe the backscattering properties of glass-bead retroreflectors that uniquely combines diffraction calculations with ray tracing based on the microscopic properties of the screen. We validated our simulation method by measurements performed on commercial retroreflective samples.

Ubiquitin-activating enzyme, E1, is associated with maturation of autophagic vacuoles.

The ubiquitin-activating enzyme, E1, is required for initiating a multi-step pathway for the covalent linkage of ubiquitin to target proteins. A CHO cell line containing a mutant thermolabile E1, ts20, has been shown to be defective in stress-induced degradation of proteins at restrictive temperature (Gropper et al., 1991. J. Biol. Chem. 266:3602-3610). Parental E36 cells responded to restrictive temperature by stimulating lysosome-mediated protein degradation twofold. Such a response was not observed in ts20 cells. The absence of accelerated degradation in these cells at 39.5 degrees C was accompanied by an accumulation of autolysosomes. The fractional volume of these degradative autophagic vacuoles was at least sixfold greater than that observed for either E36 cells at 30.5 degrees or 39.5 degrees C, or ts20 cells at 30.5 degrees C. These vacuoles were acidic and contained both acid phosphatase and cathepsin L, but, unlike the autolysosomes observed in E36 cells, ubiquitin-conjugated proteins were conspicuously absent. Combined, our results suggest that in ts20 cells, which are unable to generate ubiquitin-protein conjugates due to heat inactivation of E1, the formation and maturation of autophagosomes into autolysosomes is normal, but the conversion of autolysosomes into residual bodies is disrupted.

[Testicular adrenal rest tumors (TART) in adult men with classic congenital adrenal hyperplasia (CAH)]. / Testikuläre adrenale Resttumoren (TART) bei erwachsenen Männern mit klassischem adrenogenitalen Syndrom (AGS).

BACKGROUND: Information about treatment of adult male patients with congenital adrenal hyperplasia (CAH) and testicular adrenal rest tumors (TART) is scarce. Diagnostic and therapeutic guidelines do not exist. The aim of this review is to evaluate the current state of therapeutic options in adult male patients with CAH. METHODS: We performed an extensive search of the literature of the last 10 years by using PubMed/MEDLINE. RESULTS: The aims of treatment in adult male patients with CAH are prevention of adrenal crisis and TART, improvement of general well-being, good quality of life and sexual well-being, fertility, and prevention of side effects of gluco- and mineralocorticoid therapy. However, fertility is impaired in these patients and correlates with TART. The current therapeutic concepts are discussed. CONCLUSIONS: A future system of regular follow-up visits and standards in therapeutic concepts is needed to guarantee an improved fertility and lifelong good quality of life in adult male patients with CAH.

Regulation of protein secretion by crinophagy in perfused rat liver.

We examined the secretion of three serum proteins, albumin (RSA), alpha 2 mu-globulin (alpha 2 mu G), and transferrin (Trf), in the isolated perfused liver. Within 4 h of perfusion, only 20 to 35% of previously synthesized proteins were secreted by the liver into the recirculating medium. Low temperature inhibited the secretion of alpha 2 mu G and Trf, but not RSA. The amount of RSA secreted by the liver increased twofold in the presence of leupeptin, a proteinase inhibitor, or primaquine, a weak base capable of neutralizing acidic compartments. Neither drug affected Trf secretion, while the release of alpha 2 mu G was enhanced threefold by primaquine treatment. Only 55 to 70% of the total amount of these serum proteins present in the liver at the onset of perfusion could be accounted for after 4 h of perfusion. Our evidence suggests that these losses are due to protein degradation. The degradation of RSA and alpha 2 mu G was inhibited at 15 degrees C and by both leupeptin and primaquine. Contrary, RSA degradation was not altered when livers were perfused at 20 degrees C. Morphological techniques combined with immunological probes were utilized to identify possible intracellular sites of RSA degradation. RSA and cathepsin L were colocalized to large vacuoles found near the cell periphery. Entry of RSA into these vacuoles occurred at 20 degrees C but not at 15 degrees C. Our results using perfused rat livers suggest that as much as 40% of hepatic serum proteins are degraded via fusion of secretory vesicles with lysosomes (e.g., crinophagy).

Angiotensin II regulation of plasminogen activator inhibitor-1 gene expression in neurons of normotensive and spontaneously hypertensive rat brains.

Neuronal cells in primary culture from the hypothalamus-brain stem areas of normotensive [Wistar-Kyoto (WKY)] and spontaneously hypertensive (SH) rat brains have been used in the present study to investigate an interaction between the brain renin-angiotensin II system and the plasminogen activator system. This is an attempt to further our understanding of the role of brain Ang II in the control of neuronal development and differentiation through its regulation of the extracellular matrix. Ang II caused a 10-fold stimulation of plasminogen activator inhibitor-1 (PAI-1) messenger RNA (mRNA) in WKY rat brain neuronal cultures. The stimulation was mediated by the AT1 receptor subtype and was accompanied by an increase in PAI-1 gene transcription and the synthesis of cellular PAI-1 protein. The stimulation involved activation of protein kinase C, and alterations in the intracellular Ca2+ pool caused a significant inhibition of Ang II stimulation of PAI mRNA. Ang II stimulation of PAI-1 mRNA succeeded its action on c-fos mRNA and was attenuated by c-fos antisense oligonucleotide. Although PAI-1 gene expression was also stimulated by Ang II in neuronal cultures of SH rat brain, two differences between WKY and SH rat brain neurons were observed: 1) the level of Ang II stimulation in SH rat neurons was 50% of that in WKY rat neurons; and 2) Ang II stimulation of c-fos was 2.4-fold higher in SH neurons than in WKY neurons, but c-fos antisense oligonucleotide did not attenuate the stimulatory action of Ang II on PAI-1 mRNA in SH neurons. These observations suggest that the changes in the Ang II-mediated signaling pathways and/or the regulatory region(s) of the PAI-1 gene may contribute to the differential actions of Ang II in WKY and SH rat brain neurons.

Inflammatory mediators, infection, sepsis, and multiple organ failure after severe trauma.

The relation of (multiple) organ failure (OF) to the release of inflammatory mediators and the incidence of infection and sepsis was studied prospectively in 100 patients with multiple trauma (injury severity score = 37). Sixteen patients died of OF, 47 patients survived OF, and 37 patients had no OF. Fifteen (24%) of the patients with OF showed no signs of infection. In patients with early onset of OF (n=45), infection followed with a lag of 2 or more days. In 16 (44%) of these patients, infection led to a deterioration in organ function. With late onset of OF (n=18), infection preceded OF in nine patients. Polymorphonuclear leukocyte-elastase, neopterin, C-reactive protein, lactate, antithrombin III, and phospholipase A discriminated significantly among the three outcome groups. Of all factors, only polymorphonuclear leukocyte-elastase showed a difference between patients with and without infection or sepsis, respectively. These data indicate that infection might not play a crucial role in the pathogenesis of posttraumatic OF in a substantial portion of patients with trauma. Early OF, especially, seems to be mainly influenced by the direct sequelae of tissue damage and shock (eg, the release of inflammatory mediators). Since infection and sepsis did not lead to an augmented release of mediators in patients with trauma, the role of both entities remains unclear.

Rapid detection of elevated prostate-specific antigen levels in blood: performance of various membrane strip tests compared.

OBJECTIVES: To compare the ability of four commercially available membrane strip tests to detect increased (4 microg/L or more) concentrations of prostate-specific antigen (PSA) in blood. METHODS: Serum samples with PSA concentrations less than 4 microg/L (n = 67) and from greater than 4 microg/L to 20 microg/L (n = 32) were independently examined by two observers using the PSA membrane strip tests from Chembio, Medpro, Seratec, and Syntron. The positive and negative results of each membrane strip test were classified as either true positive or negative and false negative or positive by comparing them with the quantitative PSA assay of Immulite DPC using the conventional threshold value of 4 microg/L. RESULTS: The interobserver variations of the tests were between 93% and 97%. The color stability of the Seratec and Chembio tests did not show significant differences between test results read within 10 to 20 minutes of the reaction time; however, the results of the other two tests were especially affected by variations in the reading time. The sensitivity and specificity of the tests in relation to the threshold of 4 microg/L were 67% to 93% and 87% to 97%, respectively. CONCLUSIONS: The Syntron test and, within certain limitations, the Seratec test fulfill the concept of a rapid and convenient PSA determination to detect PSA concentrations greater than 4 microg/L. Methodologic optimization of the tests by a grading of the PSA measuring ranges (eg, between 0 and 2, 3 and 4, 4 and 6, and 7 and 10 microg/L) should be taken into account for future development.

Comparison of different methods of treating varicocele.

Varicocele treatment was performed in 331 patients. One hundred fifteen patients were operated upon according to the technique of Bernardi (1947), 80 patients underwent occlusion of the testicular vein by detachable balloons, 47 patients were treated with percutaneous sclerotherapy, and 89 patients underwent laparoscopic varicocele treatment. The laparoscopic occlusion of the testicular vessels was done in two different ways: (1) coagulation of the testicular veins with electrocoagulating tweezers, and (2) occlusion of the suprainguinal testicular vessel with metal clips and transection of the vessels. Laparoscopic Group 1 showed a clearly higher complication rate and recurrence rate in comparison with the other methods, whereas in Group 2 we observed the best results with only 4% complications and recurrences. Because of its higher complication rate and recurrence rate, laparoscopic electrocoagulation of the testicular veins proved to be inadequate.

3.0 T high-resolution MR imaging of carpal ligaments and TFCC.

PURPOSE: To determine the diagnostic value of 3.0 Tesla MRI for imaging carpal ligaments and triangular fibrocartilage complex (TFCC). Image quality of different optimized MRI sequences is evaluated for high resolution wrist anatomy. MATERIALS AND METHODS: Ten healthy volunteers were examined at 3.0 T and 1.5 T using following sequences: T1 SE, fat-saturated PD-/T2-TSE, TIRM, 3D T1/T2* DESS, 3D-CISS, 2D and 3D T2* MEDIC. Voxel size varied from 0.2 x 0.2 x 1.5 mm (2D sequences) to 0.33 mm (3) and 0.26 mm (3) (3D sequences). Image quality (signal-to-noise-ratio, contrast-to-noise-ratio, artifacts) and carpal ligament/TFCC detection rate were judged by a score. The results obtained from the 3.0 T and 1.5 T devices were compared. RESULTS: With identical voxel size, image matrix and FOV, 3.0 T MRI provided significantly better image quality and ligament detection rates for all sequences in comparison with 1.5 T. The 2D and 3D MEDIC sequences yielded best image quality and detection rates. Excellent image quality and visualization of ligament structures by the fat-suppressed PD-TSE sequence were compromised by a relatively high susceptibility to pulsation and motion artifacts. T1 SE and 3D DESS sequences gave moderate image quality and allowed only partial differentiation between ligament structures. TIRM, T2-TSE and 3D-CISS sequence proved to be unsuitable for examining ligaments at 3.0 T due to their poor image quality and detection rate. CONCLUSION: 3.0 T MRI of the wrist proved to be superior to 1.5 T MRI for high-resolution imaging of carpal ligaments and TFCC using 2D and 3D T2* MEDIC sequences. Clinical studies investigating ligament injuries or carpal instability are recommended for evaluating clinical relevance of high-resolution MRI of the wrist.

[Pneumocysts juxta-articular to the ilial bone and the sacral bone]. / Juxtaartikuläre Pneumatozysten im Os ilium und Os sacrum.

PURPOSE: The purpose of the study was to detect and safely diagnose pneumatocysts by means of computed tomography. METHODS: From September 1995 to May 1996 computed tomography of the pelvis was performed in six patients for various indications. A slice thickness of 8 mm was employed for all studies. One patient had undergone surgery for hyperparathyroidism nine years previously. Attenuation values within the coincidentally diagnosed pneumatocysts were obtained. RESULTS: We found a total of 14 pneumatocysts juxtaarticular to the sacroiliac joint. Three patients demonstrated a bilateral intraarticular vacuum phenomenon, yet a joint communication was not found. The lesions did not coincide with inflammation, tumour or trauma. CONCLUSION: Pneumatocysts are benign bone lesions associated with arthrotic changes of the sacroiliac joint. Computed tomography is the modality of choice for the diagnosis of pneumatocysts.

Ultrastructure of feeding in the karyorelictean ciliate Tracheloraphis examined by scanning electron microscopy.

The karyorelictean ciliate Tracheloraphis is considered to be among the most primitive of the extant ciliates based on both nuclear and somatic characters. These organisms lack the elaborate oral ciliation present in most ciliates. Their mode of ingestion is a type of phagocytosis through a non-ciliated region, the glabrous stripe, which runs the length of the cell. This type of ingestion is reminiscent of feeding in amoebae and some flagellate groups. It is possible that ciliate oral structures evolved within the karyorelictean ciliates from an ancestor resembling Tracheloraphis. We studied the ingestion process in a Tracheloraphis species from the Chesapeake Bay using scanning electron microscopy. The results indicate that the anterior terminus of the organism is not involved in the actual ingestion process, only the glabrous stripe. There is some interaction between the food particle and the surface of the stripe, possibly mediated by a substance secreted by the underlying extrusomes. The somatic cilia do not appear to be involved. The stripe invaginates at the ingestion site engulfing the particle. The cell becomes greatly distended at this site, but neither the anterior nor posterior terminus is affected.

Laser surgery in superficial penile tumours.

The first results of laser surgery in superficial penile tumours are reported. In 2 patients with condylomata acuminata, 2 cases of giant condylomata Buschke-Löwenstein and in 2 patients suffering from early stage penile cancer diagnostic and/or therapeutic treatments using carbon dioxide or neodymium-YAG laser have been performed. In one patient with giant condyloma a recurrent tumour was found 5 weeks after the initial treatment and a second one using CO2 laser was done. All other patients are tumour-free with a follow up of 6-24 months and erectile function is normal. Therefore, in superficial penile tumours laser treatment is an excellent alternative therapeutic approach.

Renal autotransplantation for idiopathic retroperitoneal fibrosis.

Extensive loss of the ureter is a potential complication of surgery performed to relieve ureteral obstruction caused by retroperitoneal fibrosis. The authors describe the twelfth case managed successfully by renal auto-transplantation and review the literature.

On the therapy of urolithiasis in chronic renal failure.

A resigning attitude in respect to patients suffering from nephrolithiasis and manifest renal failure is not justified anymore in view of the advances in diagnosis and therapy. During the period 1964-1975, at the urological clinic of the hospital Friedrichshain 188 patients suffering from nephrolithiasis and renal failure have been treated: 120 surgically and 68 conservatively. The operative-therapeutical conception is outlined. The pre- and postoperative hemodialysis therapy is described in detail and the different indications of hemodialysis according to the stage of renal failure are elaborated. Tabulated data demonstrate the fate of all surgically treated patients.

[Diagnosis of chronic prostatitis]. / Diagnostik der chronischen Prostatitis.

The new classification of prostatitis syndromes by the National Institutes of Health clearly defines the diagnostic criteria for categorization according to the clinical symptoms. In addition to the validated symptom scores, the four-glass test demonstrating increased numbers of leukocytes and/or bacteria serves for differentiating between the symptoms. Increased levels of leukocytes and/or increased bacterial count in expressed prostatic excretion (EPS) are typical of prostatitis, although there is a high degree of correspondence with the VB3 fraction (urine voided after prostatic massage). The detection of peroxidase cells (granulocytes) and of an increased concentration of polymorphonuclear (PMN) leukocyte elastase in the ejaculate are indicative of uroadnexitis. Nonbacterial forms of prostatitis (NIH III) and increased PSA levels require intensive clinical diagnosis.

[European Association of Urology guidelines on urinary and male genital tract infections]. / Synoptische Leitlinie der sexuell übertragbaren Erkrankungen (STD) mit Primärsymptomen im männlichen Genitale (S1). Leitinien der Deutschen Gesellschaft für Urologie.

Today, the classical bacteria that cause venereal diseases, e.g. gonorrhea, syphilis, chancroid and inguinal granuloma, only account for a small proportion of all known sexually transmitted diseases (STDs). Other bacteria and viruses as well as yeasts, protozoa and epizoa must also be regarded as causative organisms of STD. Taken together, all sexually transmitted infections comprise more than 30 relevant STD pathogens. However, not all pathogens that can be sexually transmitted manifest diseases in the genitals and not all infections of the genitals are exclusively sexually transmitted. Concise information and tables summarising the diagnostic and therapeutic management of STDs in the field of urology allow a synoptic overview, and are in agreement with the recent international guidelines of other specialist areas. Special considerations (i.e. HIV infection, pregnancy, infants, allergy) and recommended regimens are presented.

[Genitourinary tuberculosis in Germany: diagnosis and treatment]. / Urogenitaltuberkulose in Deutschland : Diagnose und Behandlung.

Genitourinary tuberculosis (GUTB) usually results from the reactivation of old, dormant tuberculous diseases by pathogens of the Mycobacterium tuberculosis complex. The diagnosis of tuberculosis of the urinary tract is based on the case history, the finding of pyuria in the absence of infection as judged by culture on routine media and by radiological imaging. A positive yellow egg culture and/or histological analysis of biopsy specimens possibly combined with the polymerase chain reaction (PCR) is still required in most patients to establish a definitive diagnosis of GUTB. Antituberculous drug treatment is based on an initial 2 month intensive phase with three or four drugs daily followed by a 4 month continuation phase with only two drugs. Surgery as a treatment option in GUTB might be indicated in complicated urinary tuberculosis. After antituberculous treatment of GUTB a follow-up surveillance over 5 years is recommended. Although the incidence of GUTB in Germany is relatively low, it is still necessary to impart and deepen scientific knowledge of the diagnosis and therapy of GUTB.

High-resolution magnetic resonance imaging of trabecular bone in the wrist at 3 tesla: initial results.

PURPOSE: To evaluate the feasibility of high-resolution magnetic resonance imaging (MRI) of trabecular bone of the wrist at 3 Tesla (3T) in vivo and to assess the potential benefit of the increased resolution for clinical assessment of structural changes in spongy bone. MATERIAL AND METHODS: High-resolution MRI of the wrist was performed with a whole-body 3T MR scanner using a dedicated circularly polarized transmit-receive wrist-coil. Two 3D-FISP sequences with a spatial resolution of 300 x 300 x 300 microm3 in a measuring time of TA = 7:51 min, and 200 x 200 x 200 microm3 in TA = 9:33 min were applied. Seven young healthy volunteers and three elderly subjects with suspected osteoporosis were examined. The signal-to-noise ratio (SNR) in the optimized setup at 3T was compared to measurements at 1.5T. RESULTS: The images at 3T allow microscopic analysis of the bone structure at an isotropic spatial resolution of 200 microm in examination times of <10 min. Differences in the structure of the spongy bone between normal and markedly osteoporotic subjects are well depicted. The SNR at 3T was found up to 16 times higher than at 1.5T applying unchanged imaging parameters. CONCLUSION: The proposed high-resolution MRI technique offers high potential in the diagnosis and follow-up of diseases with impaired bone structure of hand and/or wrist in clinical applications.