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Biomedical subjects

W Arnold

Publications and source records attributed to W Arnold.

At least 127 records · Page 7Linked to original sources
PubMed1996

Diversity of uncultured microorganisms associated with the seagrass Halophila stipulacea estimated by restriction fragment length polymorphism analysis of PCR-amplified 16S rRNA genes.

The diversity of microorganisms associated with the leaves of the seagrass Halophila stipulacea in the northern Gulf of Elat was examined by culture-independent analysis. Microorganisms were harvested by a sonication treatment for total-community genomic DNA isolation. Oligonucleotides complementary to conserved regions in the 16S rRNA-encoding DNA (rDNA) of bacteria were used for PCR amplification. The 16S rDNA PCR products were subcloned and further characterized by a restriction fragment length analysis termed ARDRA (amplified rDNA restriction analysis). These analyses were carried out after reamplifying the cloned fragments with two primers binding symmetrically to the plasmid immediately on both sides of the cloned insert. Computer-aided clustering was performed after separate restriction analysis with enzymes HinfI and HpaII. By this method, 103 cloned 16S rDNA fragments were clustered into a total of 58 different groups. Sequence analysis of clones with an identical ARDRA pattern confirmed that members of an ARDRA group were closely related to each other. The sequenced clones were found to be affiliated with a marine snow-associated plastid-like rRNA clone and with a marine Hyphomonas strain, respectively. The method applied in this study could be useful for the routine study of other microbial communities of interest.

Bacteria↗
PubMed1996

Assessment of the appropriateness of services provided by a multidisciplinary meningomyelocele clinic.

Since 1969, the Meningomyelocele Clinic at British Columbia's Children's Hospital has been serving the needs of children with spina bifida. In 1994, the clinic provided urgent and routine multidisciplinary clinical assessments to 330 patients and families. The purpose of this study was to assess, from the patients' and families' perspective, the appropriateness of the frequency of routine clinic visits and the value of the health services provided. Sixty-five patients/families were interviewed and completed a questionnaire developed by the clinic. Current visit frequency and services provided appear to meet the patient/family needs. The medical and nursing contributions were seen as valuable resources for the patient/families resulting in most patient/families feeling well informed about spina bifida.

Child↗
PubMed1996

Somatostatin receptor scintigraphy and therapy of neuroendocrine (APUD) tumors of the head and neck.

Through the development of somatostatin scintigraphy with the labeled somatostatin analog Indium111-Octreotide, it has recently become possible to accurately diagnose primary tumors of the APUD system as well as their metastases, since these tumors usually have somatostatin receptors. Experience with this method is already available for endocrine and exocrine tumors of the gastrointestinal tract, neuroendocrine and breast tumors, small cell bronchial carcinomas and certain lymphomas. In the present study, this new diagnostic technique was used for the first time in various head and neck tumors (carcinoid of the larynx, Merkel cell tumor, glomus tumor of the carotid and glomus jugulare tumor). Concurrently, some of these tumors shown by this diagnostic method to be somatostatin receptor positive were treated using the somatostatin analog Octreotide, a therapeutic approach new for the ENT-specialty. Our initial results prove that the detection of the ENT tumors which we studied by means of receptor scintigraphy is reliable. The preliminary results of this Octreotide therapy show a growth inhibitory effect, especially for those tumors of the head and neck which are inoperable or are difficult to approach surgically.

Adult↗
PubMed1996

Measles virus in otosclerosis and the specific immune response of the inner ear.

Histologic and immunohistochemical studies of otosclerotic lesions have shown that there is a chronic inflammatory reaction of the otic capsule with bone resorption resulting from vascular invasion accompanied by inflammatory cells. During the active lytic stage of otosclerosis, paramyxoviral structures have been identified by electron microscopy and measles virus antigen expression by immunohistochemistry. Recently, measles virus related sequences have been detected in tissue of otosclerotic lesions. Because the otosclerotic focus has a close relation to the perilymphatic space, the expression of measles virus antigens within it should represent an immunologic challenge to the immune system of the endolymphatic sac. In this study, measles virus specific antibodies were detected in all of the perilymph samples from 19 patients suffering from otosclerosis, and the relative amount of these IgG antibodies was much higher than in serum samples of the same patients or in perilymph of control patients. These findings support the hypothesis that measles viruses play an crucial role in the pathogenesis of otosclerosis.

Antibodies, Viral↗
PubMed1996

[Pathogenesis of otosclerosis. "State of the art"].

Women suffer from otosclerosis 1.6 times more often than males. Histologically, otosclerotic foci can be found in temporal bones of females 1.9 times more often than in those of males. Characteristic topographic regions are the oval window, round window niche and promontory. Otosclerosis can also occur principally in any area of the enchondral/periosteal layer of the otic capsule. Evidence is presented that otosclerosis is an inflammatory tissue reaction associated with macrophages, T- and B-lymphocytes, HLA-DR positive cells and plasma cells. Dependent on the stage of the osteolytic bone disease present deposits of complement and immunoglobulins (IgG, IgA) can be found. These immunoglobulins have been identified as antibodies to measles virus proteins. Using the polymerase chain reaction we were successful in demonstrating RNA sequences of measles viruses in otosclerotic bone from footplates removed during stapes surgery. Since most of the otosclerotic lesions were in direct contact to the perilymphatic space, it may be expected that the endolymphatic sac--as the immune competent organ of the inner ear--specifically reacts to antigens delivered from the otosclerosis focus into the perilymph. Perilymph samples from patients were collected during stapes surgery and their antibody titers against measles were compared with that in corresponding blood serum. All samples revealed a significantly elevated-specific anti-measles IgG amount which was significantly higher than in the corresponding serum. In contrast, antibody titer in the perilymph against herpes simplex or cytomegalo viruses did not differ from that of the serum. These findings indicate that otosclerosis is a measles virus associated inflammatory osteolytic disease of the temporal bone. Since women suffer from severe measles virus infections more often than males, it can be hypothesized that females have a higher susceptibility of their cochleo-vestibular tissues to these infections (organotropism). In addition, estrogens are well-known stimulators of osteocytic activity and may play a dominant role during ossification of an otospongeotic bone lesion. This may explain the onset of a conductive hearing loss due to otosclerosis during pregnancy.

Adult↗
PubMed1995

The insertion sequence element ISRm2011-2 belongs to the IS630-Tc1 family of transposable elements and is abundant in Rhizobium meliloti.

The insertion sequence (IS) element ISRm2011-2 of Rhizobium meliloti (Rm) is characterized by 19-bp imperfect terminal inverted repeats (three mismatches) and a size of 1053 bp. Upon transposition, ISRm2011-2 generates a putative target duplication of 2 bp. ISRm2011-2 carries two major overlapping open reading frames (ORFA and B) with a coding capacity of 135 and 201 amino acids (aa), respectively. A potential translational frameshifting window (5'-AAAAAAAG) is located in the overlapping region of both ORFs. The putative fusion product of both proteins, which probably represents the mature transposase, has a predicted molecular mass of 35.8 kDa and a pI of 10.5. Comparison of the deduced aa sequence of ORFA with database entries revealed homology to putative transposases of some IS elements of the IS3 family, as well as to eukaryotic transcription factors. The protein encoded by ORFB shows homology to transposases (Tps) of the recently proposed IS630-Tc1 family which includes Tps of both prokaryotic and eukaryotic transposable elements. Analyses of the distribution of ISRm2011-2 in natural Rm populations showed that this IS element is abundant in Rm strains.

Amino Acid Sequence↗
PubMed1995

Suppression of tumorigenicity of breast cancer cells by transfer of human chromosome 17 does not require transferred BRCA1 and p53 genes.

A number of candidate tumor suppressor genes located on the human chromosome 17 are thought to have a role to play in the development of breast cancer. In addition to the p53 gene on 17p13.1 and the BRCA1 gene mapped to 17q12-21, other chromosomal regions for tumor suppressor genes have been suggested to exist on 17p13.3 and both the central and the distal parts of 17q, although definitive functional proof of their involvement in breast cancer tumorigenesis is still lacking. In this report we show that microcell transfer of a human chromosome 17 into wild-type p53 breast cancer cells CAL51 results in loss of tumorigenicity and anchorage-independent growth, changes in cell morphology and a reduction of cell growth rates of the neo-selected microcell hybrids. In the hybrid cells, which express the p53 wild-type protein, only the p- and the distal parts of the q arm of donor chromosome 17 are transferred. Thus, our results provide functional evidence for the presence of one or more tumor suppressor gene(s) on chromosome 17, which are distinct from the p53 and the BRCA1 genes.

Animals↗
PubMed1995

Suppression tuning characteristics of the 2 f1-f2 distortion-product otoacoustic emission in humans.

The suppression tuning properties of the 2 f1-f2 distortion-product otoacoustic emission (DPOAE) were measured in 16 ears of normally hearing human subjects. DPOAE were elicited by fixed, low-level primary tones in four frequency regions with the second primary tone frequency f2 at 1, 2, 4, and 6 kHz. For various suppressor frequencies, suppression of the DPOAE was measured as a function of the suppressor tone level, enabling the assessment of the threshold and the growth of suppression. Depending on the distance of the suppressor tone to f2, there were marked differences in the suppression behavior of different suppressor frequencies. The threshold of suppression was minimal slightly above f2 and hardly increased with increasing frequency, but increased continuously with decreasing suppressor frequency. The growth of suppression, however, did not systematically change below f2, but decreased rapidly above f2. Both changes resulted in asymmetrical, V-shaped suppression tuning curves. They were sharply tuned to a frequency slightly above f2, with Q10 dB values up to 7.87. This is consistent with the assumption that the main source of the DPOAE is at the f2 site. In some cases, the DPOAE was particularly sensitive to suppressor tones near the DPOAE frequency. In one individual case, facilitation was found for corresponding frequency-level ranges of the suppressor tone. This may suggest a secondary emission source at the distortion product place.

Acoustic Stimulation↗
PubMed1995

Cytoskeletal proteins in human hair cells.

Human cochlear and vestibular hair cells (HCs) were analysed for the three major cytoskeletal types of structures: microfilaments, microtubules, and intermediate filaments and several of their associated proteins. Specific immunomorphological features were identified: the apical surface, the infracuticular rod of F-actin, the cytoplasm and the HC bases and their interactions with adjacent supporting cells. There is morphological evidence for at least three functionally interacting units: the OHC as a cytoskeletal string interacting with the Deiter's cell, being a part of the rigid pancellular protein shell of the organ of Corti; compartmentalization of HCs (surrounded by rigid intermediate filament proteins in the supporting cells); and a calcium-guided short-loop feed-back control of type I HCs. The cytoskeletal composition of all four types of human HCs and their adjacent structures is similar to, although not identical with, corresponding compositions in other mammalian species.

Actins↗
PubMed1995

The significance of the human endolymphatic sac and its possible role in Menière's disease.

Modern immunohistochemical methods allow a functional characterization of the human endolymphatic sac (ES) and its associated cell populations. The currently available immunohistochemical data of the extraosseous part of the human ES support the assumption that the epithelium is metabolically active and capable of both secretion and adsorption. The reactivity of the epithelial cells with antibodies against neuroendocrine antigens imply a paracrine activity of the human ES. Further results provide evidence for a possible role of the human ES in inner ear immune defence and indicate a putative functional relationship of the human ES to the common mucosa-associated immune system (MALT).

Cell Division↗
PubMed1995

Otosclerosis: a measles virus associated inflammatory disease.

The etiology of otosclerosis is still unknown. Immunohistochemical studies have revealed the characteristics of chronic inflammation in the otospongiotic area. Paramyxoviral structures have been identified by electron microscopy and the expression of measles virus antigen has been observed by immunohistochemistry in active otosclerotic tissue. By use of the polymerase chain reaction, measles virus related sequences have been detected in otosclerotic bone tissue but not in control specimens. The aim of our study was i) to detect measles virus genome in affected patients using a more sensitive PCR system and ii) to search for anti-measles virus IgG in the perilymph. In 13 out of 14 specimens of bone fragments from surgically removed stapedes of patients suffering from otosclerosis, measles virus RNA sequences could be detected while other tissues from the same patients and from a negative control group lacked such sequences. Furthermore, IgG anti-measles virus antibodies were detected in the perilymph of 6 patients. Our results support our previously stated hypothesis that otosclerosis is a measles virus associated disease which provokes a local immune response within the inner ear.

Adult↗
PubMed1995

Comparison of fluorine-18-fluorodeoxyglucose PET, MRI and endoscopy for staging head and neck squamous-cell carcinomas.

UNLABELLED: Accurate, preoperative assessment of tumor extent and lymph node involvement is mandatory for individualized therapy in patients with squamous-cell carcinomas (SCCs) of the head and neck region. Metabolic imaging, [18F]fluorodeoxyglucose (FDG) PET and MRI were compared with postoperative, histologic tissue characterization. METHODS: Dynamic and static PET with 370 MBq [18F]FDG up to 60 min postinjection and MRI were compared prospectively in 22 patients with head and neck SCCs. PET results with and without attenuation correction were compared with postoperative T and N stages based on pathologic findings. RESULTS: Kinetic characteristics and tracer uptake intensity were similar in primary tumors and lymph node metastases. In both, FDG uptake did not reach a plateau phase 60 min postinjection. There was no statistically significant correlation of FDG uptake with plasma glucose level or histologic grading. All primary tumors were clearly demonstrated by PET, which tended to overestimate tumor size. The sensitivity and specificity for detecting individual lymph node involvement were 90% and 96%, respectively, for PET and, thus, significantly higher for MRI (78% and 71%, respectively; p < 0.05). N stages were correctly identified by MRI in only 4 patients; PET correctly staged lymph nodes in 15 of 17 patients. Based on "neck sides", the sensitivity and specificity were higher for PET, 89% and 100%, respectively, compared with MRI values of 72% and 56%, respectively. CONCLUSION: FDG-PET may be helpful in detecting occult primary tumors with positive lymph nodes.

Adult↗
PubMed1995

[Pancreatic function and quality of life after resection of the head of the pancreas in chronic pancreatitis. A prospective, randomized comparative study after duodenum preserving resection of the head of the pancreas versus Whipple's operation].

Given an indication for surgery in patients with chronic pancreatitis, such as distal common bile duct obstruction, duodenal stenosis, or dilated pancreatic duct with stones and congestion, the surgeon must decide the type of operation to perform. A duodenopancreatectomy, the Whipple procedure, is widely considered to be the gold standard. It is highly effective in relieving pain and eliminating the structural abnormalities noted above. Duodenum-preserving resection of the head of the pancreas (DPRHP) seems to be an attractive alternative to pancreaticoduodenectomy (PD) in the treatment of chronic pancreatitis. In a clinical prospective randomized trial the efficiency of both operative methods was investigated. Between 7/1987 and 12/1993 43 patients were randomly assigned to undergo either a Whipple procedure (n = 21) or DPRHP (n = 22). Data on postoperative course, mortality, and postoperative morbidity were compiled. As concerns long-term results, postoperative hormonal status (insulin, neurotensin, cholecystokinin, gastrin) was checked, basal and stimulated with a standardized meal, using standard hormonal assay kits. All patients with PD survived, whereas one with DPRHP died from peritonitis. Patients with DPRHP had a significant more rapid convalescence (16.5 vs. 21.7 days). The range for postoperative follow-up is from 36 months to 5.5 years. In the DPRHP group 18 patients are in good condition. Two had diabetes and one developed carcinoma. In the PD group one died from hepatic coma, 14 are in good condition and 6 developed diabetes. All gained body weight with an average of 6.4 vs. 4.9 kg, DPRHP vs. PD. A difference between DPRHP and PD was obvious for the postoperative hormonal status. Results are satisfactory in both groups. For patients with DPRHP however, we see a quicker convalescence and a significant benefit as concerns postoperative hormonal status.

Adult↗
PubMed1994

A 4.6 kb DNA region of Rhizobium meliloti involved in determining urease and hydrogenase activities carries the structural genes for urease (ureA, ureB, ureC) interrupted by other open reading frames.

A 4.6 kb DNA region of the Rhizobium meliloti strain AK631 was found to contain seven open reading frames (ORFs), all oriented in the same direction. The putative gene products of four of these ORFs were highly homologous to UreA, UreB and UreC of Klebsiella aerogenes, Proteus mirabilis, Proteus vulgaris and Canavalia ensiformis. The overall organisation of the DNA region analysed was ORF1, ureA (ORF2), ORF3, ureB (ORF4), ORF5, ORF6 and ureC (ORF7), indicating that the organisation of the urease structural genes in R. meliloti differs from that of other urease genes so far characterized. ORF1 was incomplete; only the 3' end of the coding region was present. The six complete ORFs coded for polypeptides of 11.1 (UreA), 8.9 (ORF3), 10.8 (UreB), 15.0 (ORF5), 13.8 (ORF6) and 60.7 kDa (UreC). No sequence homology to known polypeptides could be detected for the gene products of ORF1, ORF3, ORF5 and ORF6. Using a lacZ fusion and insertional mutagenesis it was shown that the seven ORFs identified were all located in the same transcription unit. For mutational analysis a resistance gene cassette was introduced into each of the complete ORFs resulting in apolar mutations. Mutations in ureA, ureB and ureC, but not in ORF3, ORF5 and ORF6, abolished urease activity in R. meliloti. The determination of hydrogen uptake in these R. meliloti mutants revealed that only ORF6 and ureB are necessary for hydrogen uptake.

Amino Acid Sequence↗
PubMed1994

Bladder autoaugmentation by vesicomyotomy in the pediatric neurogenic bladder.

OBJECTIVES: The authors describe the procedure of bladder autoaugmentation by vesicomyotomy in 12 pediatric patients with neurogenic bladders. METHODS: Indications for augmentation included low-capacity, high-pressure bladders with incontinence despite maximal anticholinergic therapy. Clean intermittent catheterization was successfully reinstituted postoperatively and no patient has subsequently required enterocystoplasty. RESULTS: There were no major complications and eight patients underwent concurrent procedures on the bladder. Urodynamic studies revealed a mean increase in capacity of 40% and a mean decrease in leak point pressure of 33% compared with preoperative values. CONCLUSIONS: Early clinical experience would suggest that vesicomyectomy (excision of released detrusor) offers no advantages over vesicomyotomy in pediatric patients. Vesicomyotomy (simple incision into detrusor) proved to be a simple technique that could be safely performed in pediatric patients.

Adolescent↗
PubMed1994

[Detection of somatostatin receptors in tumors in the area of the head and neck and their clinical importance].

The development of a radiolabelled somatostatin analogue Indium-111-Pentetreotide makes the detection of somatostatin receptor-bearing tumours by scintigraphic techniques possible. The existence of high-affinity binding sites for somatostatin has been described previously for most endocrine active tumours of the gastroenteropancreatic system (GEP), malignant lymphomas, small cell lung carcinomas, a subgroup of breast tumours and several types of neuroendocrine related human tumours. Using this new diagnostic tool we investigated some head and neck tumours of neuroendocrine origin (carcinoid of larynx, Merkel cell carcinoma, paragangliomas) with the newly developed radiolabelled somatostatin analogue Indium-111-Pentetreotide whether in vivo visualisation of somatostatin receptors might be possible. In cases not accessible for surgery but with a positive receptor status we started a specific therapy with the somatostatin analogue octreotide. The preliminary results suggest that this new isotopic scanning technique in a diagnostic tool and a predictive method for an effective therapy of those head and neck tumours which revealed highly specifically a positive receptor status. The therapeutical results using the somatostatin analogue octreotide indicate that this new concept is an ideal therapeutic strategy for those neuroendocrine head and neck tumours which cannot be controlled by surgical procedures.

Adult↗