Biomedical subjects

S Siemer

Publications and source records attributed to S Siemer.

30 records · Page 2Linked to original sources

PubMed1999

[Urologic importance of interventional radiology techniques].

In radiology several therapeutical methods were developed and introduced into clinical routine in the last 10 to 15 years. In part these techniques are in competition with established surgical procedures although their main advantage is significantly less invasion. For the urologist diagnostic radiological procedures like selective blood sampling from renal or suprarenal vessels for hormone determination or CT-guided biopsy of retroperitoneal tumors are of special interest as well as procedures with therapeutic aims such as placement of drainage-tubes, percutaneous therapy of varicoceles and arterial endovascular interventions for hemorrhage or vascular wall stenosis. The role of these interventional techniques relevant for urology is described and critically discussed.

Angioplasty, Balloon↗

PubMed1998

Human carbonic anhydrase XII: cDNA cloning, expression, and chromosomal localization of a carbonic anhydrase gene that is overexpressed in some renal cell cancers.

We report the cloning and characterization of a tumor-associated carbonic anhydrase (CA) that was identified in a human renal cell carcinoma (RCC) by serological expression screening with autologous antibodies. The cDNA sequence predicts a 354-amino acid polypeptide with a molecular mass of 39,448 Da that has features of a type I membrane protein. The predicted sequence includes a 29-amino acid signal sequence, a 261-amino acid CA domain, an additional short extracellular segment, a 26-amino acid hydrophobic transmembrane domain, and a hydrophilic C-terminal cytoplasmic tail of 29 amino acids that contains two potential phosphorylation sites. The extracellular CA domain shows 30-42% homology with known human CAs, contains all three Zn-binding histidine residues found in active CAs, and contains two potential sites for asparagine glycosylation. When expressed in COS cells, the cDNA produced a 43- to 44-kDa protein in membranes that had around one-sixth the CA activity of membranes from COS cells transfected with the same vector expressing bovine CA IV. We have designated this human protein CA XII. Northern blot analysis of normal tissues demonstrated a 4.5-kb transcript only in kidney and intestine. However, in 10% of patients with RCC, the CA XII transcript was expressed at much higher levels in the RCC than in surrounding normal kidney tissue. The CA XII gene was mapped by using fluorescence in situ hybridization to 15q22. CA XII is the second catalytically active membrane CA reported to be overexpressed in certain cancers. Its relationship to oncogenesis and its potential as a clinically useful tumor marker clearly merit further investigation.

Amino Acid Sequence↗

PubMed1998

[Seminal vesicle cysts associated with ipsilateral renal agenesis. Diagnosis, and long-term clinical course].

Congenital seminal vesicle cysts associated with ipsilateral renal agenesis or dysplasia are rare malformations. Even though they are more often diagnosed today due to the introduction of advanced, sectional imaging techniques as CT and MRI, no reliable data about the prevalence of this malformation are available. This study reports seven consecutive cases, with long-term follow-up in five cases (26-119 months, mean 52 months). All patients underwent sonography, excretory urography, CT and MRI. Only two of seven patients presented nonspecific symptoms of the lower urinary tract; five were asymptomatic. In all cases sonography revealed the cystic character of the retrovesical enlargement. The anatomy of the lower pelvis was most accurately shown on MRI, which depicted the ectopic insertion of the ureter into the seminal vesicle in five cases. Cysts demonstrated high signal intensities in T1- and T2-weighted spin-echo images. In five cases the CT density was over 40 HU. Whereas one patient (15 years) presented significant enlargement of the cysts 10 years after primary diagnosis with compression of the urinary bladder, four patients showed no changes of their malformation in the follow-up examinations. The present data therefore support the concept of treating only symptomatic patients.

Adolescent↗

PubMed1998

[Diagnosis of non-palpable testis in childhood: laparoscopy or magnetic resonance tomography?].

Laparoscopy and magnetic resonance imaging (MRI) are competetive tools in the diagnostic of non-palpable testis. Advantages and disadvantages of this methods will be demonstrate. 29 boys investigated for this indication with MRI. In case MRI failed to locate the testis laparoscopy was performed with a new miniaturized set of pediatric instruments (1.9 mm optic). The aim of laparoscopy was the identification of the spermatic duct and vessels and their topographic relation to the internal inguinal ring. All findings were verified by open surgical procedures. MRI revealed 10 inguinal and 7 abdominal testis. There was no false positive finding. In 12 boys MRI showed no testis. 4 cases were correct negative, 8 cases were false negative (32%). In these 8 MRI-negative patients laparoscopy revealed 7 inguinal and 1 abdominal testis. The optical quality of the mini-telescope was sufficient for a 100% correct diagnosis. Laparoscopy related complications did not occur. Laparoscopy proved to be a powerful low risk diagnostic method in non-palpable testis with high sensitivity and specifity (100% correct positive, 0% false negative). Therefore lapraroscopy is recommended as primary diagnostic access for this indication. In the same anesthesia a optimal therapy is possible. Nevertheless a positive MRI-finding locates the testis reliably, whereas a negative finding always needs further exploration because testis might have been missed.

Adolescent↗

PubMed1998

Pediatric laparoscopy for nonpalpable testes with new miniaturized instruments.

New miniaturized pediatric telescopes (1.9 or 3.5 mm) and reusable instruments (3.5-mm trocars, scissors, graspers) were used for the first time in a prospective study to evaluate handling safety and efficacy in laparoscopic diagnosis of unilateral nonpalpable testes. The results were confirmed during the same anesthesia by open operation for either orchiopexy or removal of rudimentary spermatic cord structures. Laparoscopy in 13 boys revealed one abdominal testis, 5 vanishing testes, and 7 cases of inguinal retention associated with an open inner inguinal ring. The illumination and detail resolution of the minitelescope were excellent. The 3.5-mm instruments were fully functioning with regard to tissue dissection. No complications occurred. Without technical disadvantages but with increased safety for the patient, the new miniaturized pediatric laparocopic instruments indeed realize a step forward to minimal invasion in infants and children.

Child↗

PubMed1998

[Diagnosis of non-palpable testis: value of a new miniaturized laparoscope].

Laparoscopy and magnetic resonance imaging (MRI) are competitive tools in the diagnosis of nonpalpable testis. We investigated 29 boys for this indication with MRI. If MRI failed to locate the testis, laparoscopy was performed with a new, miniaturized set of pediatric instruments (1.9-mm optic). MRI revealed 10 inguinal and 7 abdominal testes. There was no false-positive finding. In 12 boys MRI showed no testis. Four cases were true negative, 8 false negative (32%). In these 8 MRI-negative patients, laparoscopy revealed 7 inguinal and 1 abdominal testis. The optical quality of the mini-telescope was sufficient for a 100% correct diagnosis. Laparoscopy-related complications did not occur. In summary, laparoscopic evaluation is the preferred method in pediatric cases of nonpalpable testes.

Adolescent↗

PubMed1997

Clonal chromosome aberrations in three of five sporadic angiomyolipomas of the kidney.

Clonal chromosomal changes were detected in three of five sporadic angiomyolipomas of the kidney irrespective of a solitary or multifocal appearance of this benign tumor type. No specific chromosomal changes have been identified. Including the cytogenetic data of the four renal angiomyolipomas reported in the literature, trisomy 7 as the single clonal chromosomal abnormality was detected in two angiomyolipomas. Because trisomy 7 has been reported in both neoplastic and nonneoplastic kidney cells, it may be assumed that trisomy 7 is already physiologically resident in renal cells but undergoes positive selection in this tumor type.

Adult↗

PubMed1997

[Injuries of the urinary system and management in multiple trauma cases].

Some of the most common lesions in patients with multiple traumas are injuries to the urinary system. A blunt trauma of the abdomen mainly leads to injuries of the kidney, ureter and/or bladder, whereas the external genitals are often damaged by contusions, decollements and even amputation. The multiply traumatized patient must necessarily be cared for and treated through an interdisciplinary cooperation. Thus, "urologisation" of the condition must be avoided, as must the non-recognition of urological injuries. Iatrogenic lesions are primarily observed in the context of urological, gynecological and surgical interventions. Immediate recognition may lead to early treatment, thereby avoiding possible, complications. The procedure for treating multiply traumatized patients will be shown using a plan of specific steps. Symptoms of injuries to the genitourinary system are usually not obvious. In most cases micro- and macro-hematuria are the leading symptoms, but they are not always demonstrable. In the acute phase the drainage of urine must be protected. It is mainly during the third step that urological lesions require surgical treatment. Catheterisation of the urethra may only be performed when the possibility of injury to it is excluded.

Amputation, Traumatic↗

PubMed1997

[Retroperitoneal cystic lymphangioma in a child].

Cystic lymphangiomas are rare, benign tumors, which are mainly located in the neck or axilla. The fourteenth reported case in the literature of a pediatric retroperitoneal cystic lymphangioma is described. Symptoms, diagnostic procedure and therapy are reported and discussed.

Child↗

PubMed1997

[Congenital cysts of the seminal vesicles with ipsilateral kidney agenesis. Clinical aspects of 7 cases].

Seminal vesicle cysts with ureteral ectopy and ipsilateral renal agenesis or dysplasia are rare congenital malformations. This study reports 7 consecutive cases in a single center and, for the first time in the literature, reports long-term results on 5 cases. Patients were between the age of 15 and 57 years. The malformation was diagnosed in all cases with excretory urography, computed tomography, magnetic resonance imaging and cystoscopy. 5 patients were followed after diagnosis for 26 to 119 months (mean 52 months). Only 2 of 7 patients primarily presented with nonspecific lower urinary tract symptoms. One patient (15 years old) showed significant enlargement of the cysts with compression of the urinary bladder and signs of urinary incontinence 10 years after primary diagnosis. The other 4 patients had no changes of their malformation. In conclusion, seminal vesicle cysts with ipsilateral renal agenesis are now more frequently diagnosed because of the increasing use of sectional imaging procedures. They are mostly asymptomatic and their morphology does not change with time. These data support the concept of only treating symptomatic patients.

Adolescent↗

PubMed1995

Influence of indomethacin and difluoromethylornithine on human tumour growth in nude mice.

Biopsy material from six human colorectal carcinomas was transplanted to 114 nude mice. A treatment protocol was established which included no treatment (control, C), indomethacin (I), difluoromethylornithine (D) or a combination of both (ID). The influence of the various drugs on tumour weight and protein kinase CK2 activity was monitored. CK2 activity was measured because in all tumours examined so far the enzyme activity was found to be enhanced several-fold when compared to the non-neoplastic tissue of the same patient. More than half of the investigated tumours showed a conspicuous reduction in weight after drug treatment, and I and the combination of D/I were significantly effective using the mixed model analysis. Furthermore, we have tried to discover whether there is a change in the subcellular localisation of protein kinase CK2 subunits associated with drug treatment. We analysed the tumours and the non-neoplastic control tissues by immunohistochemistry using antibodies directed against the CK2 subunits and against the proliferation marker Mib. In addition, we have also investigated the behaviour of the nucleolar protein B23 which has also been shown to be enhanced several-fold in rapidly proliferating tissue and which is also a substrate for CK2. The immunohistochemical data suggest that, irrespective of the drug treatment and the observed reduction in CK2 activity, the CK2 subunits remain localised in the nucleus.

Animals↗

PubMed1994

Asymmetric expression of protein kinase CK2 subunits in human kidney tumors.

Renal clear cell carcinomas and the corresponding ipsilateral control tissues were investigated for protein kinase CK2 activity and subunit ratio. The average protein kinase CK2 activity from 21 different kidney samples was 318 U/mg and that from the corresponding tumors 610 U/mg. The subunit ratio of protein kinase CK2 alpha in tumors/normal tissue (T/N) was 1.58 and that of the protein kinase CK2 beta (T/N) was 2.65. The data suggest that the generally described increase in protein kinase CK2 activity in tumor cells may to some extent result from a deregulation in subunit biosynthesis or degradation. This at least partly owing to the presence of excess enzymatically active protein kinase alpha-subunit but also to a significantly higher presence of the non-catalytic beta-subunit.

Adenocarcinoma, Clear Cell↗