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Biomedical subjects

H Lang

Publications and source records attributed to H Lang.

At least 91 records · Page 5Linked to original sources
PubMed1999

Parathyroid hormone-related protein in rat penis: expression, localization, and effect on cavernosal pressure.

Although PTH-related protein-(1-36) [PTHrP-(1-36)] is known to be expressed in smooth muscle and to exert potent myorelaxant effects, its tonic effects on cavernosal smooth muscle has not yet been explored. Using the RT-PCR technique, the present study establishes that PTHrP messenger RNA is present in microdissected corpus cavernosa in the rat. In immunohistochemical studies using affinity-purified antibodies to middle regions of PTHrP, immunostaining was localized throughout the penile structures, including vessels, cavernosal smooth muscle, and trabecular fibroblasts. Strong immunostaining for PTHrP was also detected in the dorsal nerve bundles. In anesthetized rats, intracavernosally injected boluses of increasing doses of PTHrP-(1-36) (0.3-30 pmol in 100 microl saline) had little effect on intracavernosal pressure. However, they markedly potentiated the dilatory response to papaverine (8-800 nmol), increasing the papaverine-induced intracavernous pressure by 2.5-fold, close to the mean arterial pressure. In conclusion, the cavernosal expression of PTHrP messenger RNA, the distribution of immunoreactive PTHrP throughout the structuro-functional components of the erectile apparatus and its strong potentiating action on papaverine-induced cavernosal relaxation, collectively suggest that PTHrP participates in the control of cavernosal tone.

Animals↗
PubMed1999

[Retroperitoneal mucinous cystadenoma].

The authors report an unusual case of retroperitoneal mucinous cystadenoma in contact with the isthmus of a horseshoe kidney and associated with congenital absence of the left ovary. The retroperitoneal site is very unusual, as only about twenty cases have been reported in this site. The pathogenesis of these tumours remains unclear and the authors discuss the various hypotheses proposed to date.

Cystadenoma, Mucinous↗
PubMed1999

[Study of the role of cyclin-dependent kinases (CDKs) in retinoic acid (RA) inducing HL-60 cell differentiation].

OBJECTIVE: To investigate the role of CDKs in the RA inducing HL-60 cell differentiation. METHODS: The effects of all-trans retinoic acid (ATRA) and arotinoid ethylester(AE) at the dosage of 5 x 10(-6) mol/L on the proliferation and differentiation of HL-60 cells were examined by NBT reduction test and cytometry analysis. Meanwhile, histone H1 kinase assay was used to observe the changes of CDK2 activities in HL-60 cells treatment with ATRA and AE. The amounts of both cyclin E/CDK2 and cyclin D1/CDK4 complexes were observed with immunoprecipitates. RESULTS: Both ATRA and AE inhibited the growth of HL-60 cells, arrested cells in G1/G0 phase, and induced cells to differentiation. The activities of cyclin E/CDK2 and the amounts of cyclin D1/CDK4 complexes were decreased in ATRA- or AE-treated HL-60 cells. CONCLUSION: The effects of RA on the proliferation and differentiation of HL-60 cells may be associated with significant decreases in the activities of CDKs.

Antineoplastic Agents↗
PubMed1998

Activation of various subtypes of G-protein alpha subunits by partial agonists of the adenosine A1 receptor.

The activation of different G protein subtypes by the rat adenosine A1 receptor initiated by stimulation with the full agonist 2-chloro-N6-cyclopentyladenosine (CCPA) and by six structurally distinct partial agonists of this receptor was investigated. Endogenous G protein alpha subunits in rat cortical membranes were inactivated by N-ethylmaleimide (NEM). Activation of rat recombinant myristoylated alpha(o), alpha(i1), alpha(i2) and alpha(i3) by partial agonists in comparison to the full agonist was assessed by guanosine-5'-(gamma-[35S]thio)triphosphate ([35S]GTPgammaS) binding after reconstitution of G protein alpha subunits with the adenosine A1 receptor in N-ethylmaleimide-treated membranes. 2-Chloro-N6-cyclopentyladenosine and 3' -deoxy-N6-cyclopentyladenosine (3'-d-CPA), the partial agonist with the highest intrinsic activity, were significantly more potent in activation of alpha(i) subtypes than alpha(o). In contrast, 5'-methylthioadenosine (MeSA), 2'-deoxy-2-chloroadenosine (cladribine), 2'-deoxy-N6-cyclopentyladenosine (2'-d-CPA), 2-phenylaminoadenosine (CV 1808) and C8-aminopropyl-N6-cyclopentyladenosine (C8-aminopropyl-CPA) did not exhibit higher potency for Go or any Gi subtype. All partial agonists, although carrying structurally different modifications, showed higher relative intrinsic activities in activation of Gi than of Go, indicating that Gi-coupled pathways may be activated selectively via the A1 receptor by partial agonists, but not Go-mediated responses.

Adenosine↗
PubMed1998

Volume measurements of localized hepatic lesions using three-dimensional sonography in comparison with three-dimensional computed tomography.

Three-dimensional (3D) sonography represents a further development of non-invasive, diagnostic sonographic imaging techniques. The clinical use of this technique in the hepatobiliary system reveals its possible applications, especially in the case of localized lesions. The goal of this study was to evaluate the accuracy of in vivo, three-dimensional ultrasonography with a freely moveable transducer as compared with a computerized tomographic arterial portography using the spiral technique (S-CTAP). A total of 42 patients with localized hepatic lesions (1.5 to 1231 cm3, mean 155 cm3) standard deviation (SD) 231 cm3 were examined using conventional (2D) and 3D ultrasonography (US). Eleven of these patients additionally underwent spiral CTAP. The volumes were calculated using the ellipsoid formula (2D US and 3D US) and were also reconstructed planimetrically with the aid of work stations (3D US and 3D CT). Furthermore, the intra and inter-investigator variability of the 3D planimetry was determined. The conformity of US methods with those using S-CTAP was determined with Bland and Altman s limits of agreement. Inter-rater agreement was calculated using Cohen s concordance index kappa. The deviation of 2D US from 3D CT was -62% to +68% and that of 3D US (ellipsoid) from 3D CT was -28% to +9%. Between 3D US (planimetry) and S-CTAP the deviation was -21% to 9%. The kappa value was 0.886. The intra-investigator variability was 5%. Our results show that the planimetric 3D US is independent of the investigator and, with regard to the volume determinations, is substantially more accurate than measurements with conventional sonography and comparable with those measurements made using CT investigations. 3D sonography may be applied complementarily to CT as an economical procedure for the follow-up of tumor disease.

Adult↗
PubMed1998

Asanguineous isolated hyperthermic perfusion of the liver: results of an experimental study in pigs.

Asanguineous hyperthermic liver perfusion was performed in five and seven pigs for 30 and 45 min respectively. Laboratory data, including changes of liver enzyme levels and results of liver function tests, as well as morphological alterations of liver structure, were compared with data from a 45-min oxygenated hyperthermic liver perfusion. In the group undergoing asanguineous liver perfusion survival was four of five and five of seven animals. In the oxygenated group six of seven pigs survived. Liver enzymes and function tests in the two groups with a 45-min perfusion time were not significantly different. All enzyme and laboratory test values returned to normal within 1 week. Similarly morphological changes were reversible within 1 week. The results suggest that asanguineous isolated hyperthermic liver perfusion up to 45 min is feasible without damage to liver tissue.

Animals↗
PubMed1998

The surgical technique of isolated hyperthermic arterial liver perfusion in humans.

Various techniques of isolated liver perfusions have been described, using hepatic artery or both hepatic artery and portal vein. In this paper the technique of isolated arterial liver perfusion is presented. Twelve patients suffering from non-resectable liver tumors underwent this approach. All of them had been previously unsuccessfully treated by resection or systemic chemotherapy. The liver perfusions were performed without technical problems. No operative death occurred. The mean operating time was 413 +/- 29 min. Although the perfusion medium was oxygenated and the absolute anoxic period was shorter than 10 min in all cases the perfused livers showed a marked postoperative increase of liver enzyme levels. Further studies should be aimed at reducing this hepatic injury and simplifying the complex surgical procedure.

Adult↗
PubMed1998

Anesthesiological management during isolated liver perfusion.

The treatment of irresectable hepatic metastases is limited by the systemic toxicity of anticancer agents. Isolated hyperthermic liver perfusion (IHLP) with anticancer agents is a new therapy for irresectable liver tumors. The risks of this therapy lie in the extended operation, the anhepatic phase and the possibility of liver damage due to the anticancer drug and hyperthermia. Experience of this method is rare, and the side effects are not well known. To estimate the individual risk of patients before isolated liver perfusion an extended evaluation of the preoperative conditions is usual. Titration of all anesthetic agents is advisable to prevent cardiovascular changes and to avoid an extended recovery time after therapy. Based on our experience with IHLP in ten patients, we prefer coinduction with midazolam and thiopentone. After intubation, intermittent positive pressure ventilation with positive end-expiratory pressure is instituted with 30% oxygen in air. Pancuronium bromide is used to provide muscular paralysis, and isoflurane is administered throughout the procedure. Anesthesia is supplemented by fentanyl and midazolam. Invasive hemodynamic monitors may be placed after induction of anesthesia. Our first results with IHLP indicate that, under the conditions of elevated monitoring, complete isolation of the liver, a good wash-out and a safe anesthesiological management, no major disturbances must be expected during the therapy. The patients are more compromised by the therapy during the following days. Low diastolic blood pressure and loss of resistance after perfusion were the first signs of a toxic reaction.

Adult↗
PubMed1998

[Follow-up of myasthenia gravis. Results of a longitudinal study of the significance of psychosocial predictors].

Forty-two patients suffering from myasthenia gravis were examined in a longitudinal study design. The aim of the study was to investigate possible psychosocial predictors for the course of the disease. At the time of the first examination (T1) the diagnosis myasthenia gravis had been established for no longer than 1 year. Two further examinations were done at 6 months (T2) and 18 months (T3) after T1. Methods consisted of a personality questionnaire (FPI), a coping questionnaire (FKV), an assessment of neurotic symptoms by interviewers (PSKB) and an assessment of the doctor-patient relationship by the attending physicians. Two different severity scores (Oosterhuis Index, Myasthenia Score) served as criteria for the course of the disease. There was no connection between the course of myasthenia gravis and neurotic symptoms like anxiety or depression and the quality of the doctor-patient relationship (both assessed at T1). Also demographic data were independent from the development of severity scores. The personality factor extraversion was associated with a positive course of the disease, aggressiveness and worrying about health with a negative one. Among the coping behaviors religiousness and looking for sense were associated with a favorable course but that was shown only regarding the Oosterhuis Index and not the Myasthenia Score. As several T1 personality factors were predictive for the severity scores at T3, these results may suggest a causal influence of personality factors on the severity of the illness. Whether or not this relationship is actually in operation, however, remains ellusive. Further studies using an experimental design are needed to strengthen this hypothesis.

Adaptation, Psychological↗
PubMed1998

[Standardized evaluation of red, green and blue perception. Comparison between color arrangement and computer-assisted test procedures].

BACKGROUND: Computerized colortests offer the possibility of determining quantitative color contrast thresholds under standardized conditions. Arrangement tests allow semi-quantitative evaluation of the red, green and blue color sense. To validate the results of a new computerized test, its results are compared to those of arrangement tests. PATIENTS AND METHODS: Thirty-five patients with retinitis pigmentosa (RP, mean age 38.51, +/- 15.14) as well as 30 normal observers (mean age 36.52, +/- 14.33) were evaluated. The computerized color test COLDEF was used, which is a calibrated screen that presents color optotypes on a colored background. All colors are chosen from three-color confusion axes of the CIE-Lu'v' color chart (protan, deutan and tritan axis). By a staircase procedure, the colors of the optotype and background were varied until the observers minimal color contrast threshold is detected. To compare the results of COLDEF with a routine diagnostic tool, the Farnsworth panel D-15 and Lanthony désaturé test were chosen. The results of the arrangement tests were scored by a categorization scheme. RESULTS: Normal observers showed no elevated thresholds either in COLDEF nor in the panel tests. In the RP group increased thresholds along the blue confusion axis could be detected in most cases. Furthermore, COLDEF showed increased thresholds along the red and green axes in some patients. With the computerized test it is always possible to identify the color axis concerned. The new test allows a fast and quantitative assessment of acquired color vision deficiencies.

Adult↗
PubMed1998

Two-step procedure in Budd-Chiari syndrome with severe intrahepatic vena cava stenosis: vena cava stenting and portocaval shunt.

Budd-Chiari syndrome is characterized by hepatic venous outflow obstruction, which often leads to death as a result of portal hypertension and liver failure. Venous decompressive shunt surgery and liver transplantation represent efficient surgical treatments of Budd-Chiari syndrome. In the case presented here, severe intrahepatic compression of the inferior vena cava (IVC) was caused by the hypertrophic caudate lobe. A mere portocaval shunt was not feasible because of a large pressure gradient across the intrahepatic stenosis. A two-step procedure with preoperative radiological dilation and stenting of the intrahepatic IVC followed by a portocaval shunt was successfully performed. Consequently, liver transplantation and its subsequent immunosuppression could be avoided.

Adult↗
PubMed1998

Single stones of the lower pole of the kidney. Comparative results of extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy.

OBJECTIVE: To assess the effectiveness of extracorporeal shock wave lithotripsy (ESWL) and percutaneous nephrolithotomy (PCN) as a treatment for stones of the lower pole of the kidney and to compare their morbidity according to the stone size. METHODS: We retrospectively studied 739 patients treated for a single stone of the lower pole. Group I consisted of 666 patients treated by ESWL and group II consisted of 73 patients treated by PCN. RESULTS: These were assessed at 3 months for 587 ESWL patients (88%) and at day 1 for all PCN patients on renal tomography or ultrasonography. Respectively in groups I and II, 335 patients (57%) and 53 patients (72.6%) were stone-free (p = 0.01). For medium-size (10-20 mm) stone patients, stone-free represented 102 patients (44%) and 29 patients (72.5%) in groups I and II respectively (p = 0.001). For smaller stones (< 10 mm), stone-free represented 231 patients (69%) and 21 patients (84%) in groups I and II respectively (p = 0.12). Morbidity rate was less with ESWL than with PCN. CONCLUSIONS: PCN achieves better results than ESWL for single stone of the lower pole with statistical significance for middle-size stones but with higher morbidity.

Adolescent↗
PubMed1998

Attachment formation following replantation of cultured cells into periodontal defects--a study in minipigs.

Regeneration processes in the periodontium occur by the interaction of different cell populations. It is known that these cells are also capable of forming new periodontal tissue after culture in vitro. The present study investigated whether replanted cultured cells from the periodontium could contribute to attachment formation. Primary cell cultures from alveolar bone and periodontal ligament were obtained from 11 minipigs. Experimentally induced furaction and interdental defects (n = 168) were treated in groups: (a) flap surgery, replantation of alveolar bone cells, and covering of the defects with Teflon membranes (ABC group); (b) flap surgery, replantation of periodontal ligament cells and membranes (PLC group); (c) flap surgery, bone gelatin (carrier material) and membranes (BG group); (d) flap surgery and membranes (NBG group); (e) flap surgery (FS group); and (f) no treatment (NT group). The defects were clinically and histologically (polyfluorochrome labeling) assessed after 10, 30, and 90 days. In the ABC group, initial calcified tissue formation at the roots was apparent after only 8 days. Marked new formation of cementum and alveolar bone and the development of a new attachment were observed after 90 days. In the BG and the NBG groups, wound healing varied depending on membrane healing and the morphology of the defects, which led to significantly poorer and variable results. Similar results were found in the PLC group, although some defects showed extensive cementum and bone formation. Defects in the FS and the NT groups healed largely by epithelialization. The study shows that replantation of cultured alveolar bone cells leads to formation of new cementum and bone, which, in turn, leads to formation of a new attachment. It is likely that the cells stabilize the tissue formation in the defect or on the root surface in the early phase of wound healing and prevent epithelial downgrowth. Results also show that regeneration in the periodontium is determined by the availability of (precursor) cells capable of forming calcified tissues.

Alveolar Process↗
PubMed1998

Abnormal frequency mismatch negativity in mentally retarded children and in children with developmental dysphasia.

The auditory event-related potential waveform termed "mismatch negativity" was examined in 12 mentally retarded children with delayed development of speech and language (aged 5-8 years) and in 13 children with developmental dysphasia (aged 5-9 years). The mismatch negativity waves were elicited with pure sine-wave tone stimuli using the oddball paradigm. We measured the peak latency and peak amplitude of mismatch negativity responses to frequency (500/553 Hz) difference. The mismatch negativity patterns were compared with those of 10 children with normal development of linguistic skills (aged 5-9 years). In both the mentally retarded and dysphasic groups, the peak amplitude of the frequency mismatch negativity was significantly attenuated when compared with the control group, but no significant difference was observed between the mentally retarded and dysphasic groups. Attenuated frequency mismatch negativity was related to impairment of linguistic skills irrespective of the child's cognitive skills. Because the mismatch negativity response reflects central auditory processing and is modal specific for auditory stimuli, this change-specific response can serve as an objective tool to elucidate central auditory deficits in children.

Aphasia↗
PubMed1998

[Education in psychosomatic medicine and psychotherapy specialty: evaluation by students].

In the context of evaluation, experiences, attitudes, expectations and assessments concerning teaching psychosomatic medicine and psychotherapy were examined. For that purpose students of the winter term 1993/94 were given a questionnaire before and after the practical course. The students had little experience with the subject. They described low expectations regarding the training. However, they showed a very positive attitude towards the subject. After the course, they judged the training positively. In particular, the affective-subjective contents, considered as being typical for the subject, correlated with positive judgements of the teaching. Thus, in may be concluded that these aspects may be conveyed to the students by means of a Balint-like method of teaching and that these aspects are accepted by the students.

Adult↗
PubMed1998

First experience and technical aspects of isolated liver perfusion for extensive liver metastasis.

BACKGROUND: New drugs and modalities for locoregional tumor treatment in recent years may offer new potential for isolated liver perfusion in patients with nonresectable liver tumors. The purpose of this study was to prove the feasibility of arterial isolated liver perfusion and to assess the tolerance of perfusion with high-dose tumor necrosis factor (TNF). METHODS: Twelve patients with extensive liver metastases previously treated unsuccessfully with systemic chemotherapy underwent isolated hyperthermic liver perfusion using a heart-lung machine. High doses of mitomycin were administered in the first six and a combination of TNF and melphalan in the last six patients. RESULTS: No operative death occurred and no direct postoperative liver failure was observed in any patient. In cases of variations of the arterial hepatic blood supply, the perfusion was done through the splenic artery or an angiography catheter. Histologic analysis of tumor biopsy specimens obtained on the first postoperative day revealed major tumor necrosis in 8 of 12 patients. CONCLUSIONS: Isolated arterial perfusion of the liver is a complex surgical procedure that is feasible in patients with anatomic variations of the hepatic artery. The remarkable histologic response to perfusion in several pretreated patients, especially after application of high-dose TNF and melphalan, suggests that this modality is very effective in tumor killing.

Adult↗
PubMed1998

[Volumetry of circumscribed liver changes with 3-D ultrasound in comparison with 3-D computerized tomography].

The accuracy of volume measurement using three-dimensional ultrasound (3D-US) in comparison to three-dimensional computer tomography (3D-CT) was evaluated in 11 patients. The deviation of tumor volumes measured with 3D-US (ellipsoid formula) from 3D-CT was -28% to +9% and for 3D-US (planimetry reconstruction) from 3D-CT was -21% to +9%. These data show that volume measurement using 3D-US provides comparable results to 3D-CT. Clinically, 3D-US could be helpful in the follow-up of patients with non-resectable tumors or in planning liver resections by assessing the volume of liver tissue remaining after resection or by a better visualization of the topography of liver tumors and major hepatic structures.

Follow-Up Studies↗