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M Graf

Publications and source records attributed to M Graf.

At least 37 records · Page 2Linked to original sources
PubMed2000

Experimental hypertrophy of myenteric neurones in the pig: a morphometric study.

Muscular hypertrophy in the ileum of two pigs aged 6 weeks was induced using two different surgical techniques, narrowing of the gut circumference (mechanical stenosis) and segmental reversal of an ileal loop which results in a persistent antiperistalsis of that segment (functional stenosis). These pigs were sacrificed 5-6 weeks postoperatively. Cross sections through the gut wall at various distances from the operation sites revealed marked muscular hypertrophy in the pre-stenotic regions and in the reversed segment. Whole mounts from pre- and post-stenotic, as well as reversed ileal regions, were silver- impregnated. The corresponding ileal region of a third, nonoperated pig served as control. Using a computer-aided morphometric device, somal areas of five morphological neurone types were measured at various distances orally and anally from the operation sites and along the control ileum. Values between hypertrophic and nonhypertrophic zones as well as between two corresponding zones of nonoperated ileum were compared statistically. Along the control ileum, values revealed no differences in soma sizes. Within the experimentally altered material, somal areas of type VI neurones showed marked hypertrophy related to the sites of muscular hypertrophy whereas the other types remained constant throughout (II, IV in segmental reversal) or showed slightly larger somal areas within the post-stenotic, nonhypertrophied zones (I, V, IV in stenosis). Additionally, within the reversed segment, neuronal perikarya of type I, II, IV and V neurones were larger as compared to the neighbouring regions. However, this enlargement of perikarya within the reversed segment may not be correlated with muscular hypertrophy but rather with the transections of intramural axons before reversing this segment. The results suggest that morphologically distinct neurone types may play different roles within the mechanically stressed small intestine and possibly also in the coordination of normal muscular function.

Animals↗
PubMed2000

Concerted action of multiple cis-acting sequences is required for Rev dependence of late human immunodeficiency virus type 1 gene expression.

Based on the human immunodeficiency virus type 1 (HIV-1) gag gene, subgenomic reporter constructs have been established allowing the contributions of different cis-acting elements to the Rev dependency of late HIV-1 gene products to be determined. Modification of intragenic regulatory elements achieved by adapting the codon usage of the complete gene to highly expressed mammalian genes resulted in constitutive nuclear export allowing high levels of Gag expression independent from the Rev/Rev-responsive element system and irrespective of the absence or presence of the isolated major splice donor. Leptomycin B inhibitor studies revealed that the RNAs derived from the codon-optimized gag gene lacking AU-rich inhibitory elements are directed to a distinct, CRM1-independent, nuclear export pathway.

Base Sequence↗
PubMed2000

Characterization of a virtually full-length human immunodeficiency virus type 1 genome of a prevalent intersubtype (C/B') recombinant strain in China.

A molecular epidemiology study was conducted among more than 100 human immunodeficiency virus type 1 (HIV-1) subtype C seropositive intravenous drug users (IDUs) from China. Genotyping based on the envelope C2V3 coding region revealed the highest homology of the most prevalent virus strains circulating throughout China to subtype C sequences of Indian origin. Based on these results, a virtually full-length genome representing the most prevalent class of clade C strains circulating throughout China was directly amplified from peripheral blood mononuclear cells of a selected HIV-infected IDU and subcloned. Sequence analysis identified a mosaic structure, suggesting extensive intersubtype recombination events between genomes of the prevalent clade C and (B')-subtype Thai virus strains of that geographic region. Recombinant Identification Program analysis and phylogenetic bootstrapping suggested that there were 10 breakpoints (i) in the gag-pol coding region, (ii) in vpr and at the 3' end of the vpu gene, and (iii) in the nef open reading frame. (B')-sequences therefore include (i) several insertions in the gag-pol coding region; (ii) 3'-vpr, the complete vpu gene, and the first exons of tat and rev; and (iii) the 5' half of the nef gene. Breakpoints located in the vpr/vpu coding region as well as in the nef gene of 97cn54 were found at almost identical positions of all subtype C strains isolated from IDUs living in different areas of China, suggesting a common ancestor for the C/B' recombinant strains. More than 50% of well-defined subtype B-derived cytotoxic T-lymphocyte epitopes within Gag and Pol and 10% of the known epitopes in Env were found to exactly match sequences within in this clade C/B' chimeric reference strain. These results may substantially facilitate a biological comparison of clade C-derived reference strains as well as the generation of useful reagents supporting vaccine-related efforts in China.

Amino Acid Sequence↗
PubMed1999

Comparison of losses of heterozygosity and replication errors in primary colorectal carcinomas and corresponding liver metastases.

In order to investigate genetic alterations specific to liver metastases of colorectal carcinomas, losses of heterozygosity and replication errors have been compared in 15 cases of primary colorectal carcinoma and in the corresponding metastatic liver tumours. Fifteen microsatellite markers located on 13 different chromosomal arms were used in the study. The LOH patterns of the primary and the metastatic tumours were identical in eight cases and showed differences in seven cases. Areas of deletion predominantly or completely common to the colorectal and the metastatic tumour were detected on chromosomes 5q, 8p, 17p, 18q, and 22q. Preferential loss in metastatic tumours was observed on chromosomal arm 3p. Replication errors were found in four primary tumours and in three of the corresponding secondaries. A replication error phenotype specific to a metastasis was not observed.

Adult↗
PubMed1999

Intracardiac yolk sac tumor in an infant girl.

We report about a two and a half year old girl with a primary yolk sac tumor (YST) of the heart, located in the interventricular septum. The girl was admitted to the hospital with a systolic cardiac murmur. Echocardiography revealed a smoothly surfaced tumor which based on the interventricular septum below the aortic valve and filled out more than half of the left ventricular cavity. Diagnosis of a yolk sac tumor was established on a frozen section of a biopsy taken at surgery and confirmed by the examination of the resected material. Excessively elevated serum alpha-fetoprotein (AFP) levels contributed to this diagnosis. Follow up examinations of the patient including computed tomography (CT) of head, thorax and abdomen, did not indicate an extracardiac tumor manifestation. We found no previous report of a primary intracardial yolk sac tumor in the literature.

Child, Preschool↗
PubMed1999

Extraneural metastasizing ependymoma of the spinal cord.

This paper reports a case of the rare entity of an extraneural metastasizing ependymoma of the spinal cord. The tumor which arose in the conus medullaris and in the cauda equina was first diagnosed in 1956 when a thoracolumbar myeloresection was performed. At autopsy, 40 years after the primary diagnosis, a massive local tumor recurrence with extraneural metastases in the lungs, the pleura, the liver, and the thoracal and abdominal lymph nodes were found. Immunohistochemical stains of the extraneural metastases showed a strong cytoplasmatic expression of glial fibrillary acidic protein (GFAP). Neither the primary tumor nor its metastases showed any of the conventional morphological criteria of malignancy. Reviewing the literature we discuss the possible mechanism of extraneural tumor spread and the incidence of metastases with regard to the tumor type.

Adolescent↗
PubMed1999

Beta-catenin accumulation and mutation of the CTNNB1 gene in hepatoblastoma.

Hepatoblastoma is a rare malignant tumor of the liver that occurs in children at an average age of 2 to 3 years. Epidemiologic studies have shown an increased frequency of this tumor type in families affected by adenomatous polyposis coli. In addition to the epidemiologic data, molecular genetic studies suggest that inactivation of the APC tumor suppressor may be involved in hepatoblastoma tumorigenesis. A major function of APC is the downregulation of beta-catenin, a transcription-activating protein with oncogenic potential. In an ongoing immunohistochemical study of beta-catenin expression in sporadic cases of tumor types that are associated with adenomatous polyposis coli, we observed increased beta-catenin levels in the cytoplasm and in the nuclei of three investigated hepatoblastomas. Sequencing of exon 3 of the beta-catenin gene (CTNNB1) revealed an activating mutation in one of the tumor samples. Our data indicate for the first time that beta-catenin accumulation may play a role in the development of hepatoblastoma and that activating mutations of the beta-catenin gene may substitute biallelic APC inactivation in this tumor type. Genes Chromosomes Cancer 25:399-402, 1999.

Cadherins↗
PubMed1999

[Endosonographic imaging of anal fistulas in infants].

Anorectal endosonography is established as a diagnostic tool in anorectal fistulas, today. Yet, there is still little experience with the use of this method in small children. We could visualize three intershincteric fistulas in children at an age of 6, 7 and 14 months. The procedure is well tolerated and even children under the age of one year can be examined with a special probe.

Contrast Media↗
PubMed1998

Topographical EEG analysis of rolandic spikes.

We performed topographic EEG investigation with instant voltage mapping in 57 patients with a Rolandic spike focus including 35 patients with benign Rolandic epilepsy. A pronounced maximal negativity of "Rolandic" spikes could be demonstrated over central or mid-temporal electrodes, with a spread to parietal or upper frontal areas with a dipole formation (centrotemporal negativity, frontal positivity) and involvement of midline. There was a moderate correlation between spike amplitude or duration with spread to adjacent areas. No other focal abnormalities such as focal slowing could be revealed by visual or FFT EEG analysis. During light sleep spike activity was pronounced and often associated with generalized spike wave activity. Thus, a functional disturbance rather than a structural lesion can be assumed.

Adolescent↗
PubMed1997

Congenital axonal neuropathy caused by deletions in the spinal muscular atrophy region.

Three newborn siblings presented with generalized weakness, asphyxia, facial diplegia, and external ophthalmoplegia. Electrophysiological testing showed inexcitability of motor and sensory nerves and myographic signs of denervation. Nerve biopsies and postmortem examination showed loss of myelinated fibers and axonal damage in sensory and mixed nerves. Many spinal motor neurons were chromatolytic although their number was normal. Molecular genetic investigations revealed a homozygous deletion of the survival motor neuron (SMN) gene and a loss of markers Ag1-CA and C212 in the paternal haplotype. These findings are consistent with the diagnosis of an unusually severe type of spinal muscular atrophy. Given the large extent of the deletion, it must be considered that the unusual severe phenotype with involvement of brainstem nuclei and afferent nerves might also be due to changes of yet unknown genes neighboring the SMN gene.

Axons↗
PubMed1997

Isolation and characterization of highly (R)-specific N-acetyl-1-phenylethylamine amidohydrolase, a new enzyme from Arthrobacter aurescens AcR5b.

A new amidohydrolase deacetylating several N-acetyl-1-phenylethylamine derivatives (R)-specifically was found in Arthrobacter aurescens AcR5b. The strain was isolated from a wet haystack by enrichment culture with (R)-N-acetyl-1-phenylethylamine as the sole carbon source. (R) and (S)-N-acetyl-1-phenylethylamine do not serve as inducers for acylase formation. By improving the growth conditions the enzyme production was increased 47-fold. The amidohydrolase was purified to homogeneity leading to a 5.2-fold increase of the specific activity with a recovery of 67%. A molecular mass of 220 kDa was estimated by gel filtration. Sodium dodecyl sulfate/polyacrylamide gel electrophorosis shows two subunits with molecular masses of 16 kDa and 89 kDa. The optimum pH and temperature were pH 8 and 50 degrees C, respectively. The enzyme was stable in the range of pH 7-9 and at temperatures up to 30 degrees C. The enzyme activity was inhibited by Cu2+, Co2+, Ni2+, and Zn2+, and this inhibition was reversed by EDTA.M.

Amidohydrolases↗
PubMed1997

Correlations for the Development Visual-Motor Integration Test and the Wechsler Intelligence Scale for Children-III.

Previous studies have indicated that scores on the Developmental Test of Visual Motor Integration correlate higher with Performance than Verbal and Full Scale IQs of the Wechsler Intelligence Scale for Children-Revised. WISC-III and Visual Motor Integration-3R scores from 99 boys and 46 girls ranging in age from 6 to 16 years were obtained by certified school psychologists to study the relationship between the two measures. Participants were drawn from six suburban Chicago school districts, two being very affluent. These Pearson correlations for standard scores ranging from .34 to .57 and following previous research, were ranked from highest to lowest and then transformed into an approximately normal Z statistic using Fisher Z. The highest correlation was compared to the next highest and so on, which yielded significant differences. Only four comparisons had to be made.

Adolescent↗
PubMed1997

Examining PTSD as a Complication of Infertility.

Posttraumatic stress disorder (PTSD) is a psychiatric disorder that may develop following exposure to threatened or actual injury or death. While commonly associated with war or natural disaster, symptoms of PTSD have been described in patients who are undergoing or who have completed infertility treatment or high-risk pregnancies. Three case studies of patients who developed PTSD following such pregnancies are discussed, demonstrating the variety of symptoms and presentations of these patients. The clinician must be vigilant in monitoring infertility patients with PTSD. These women, as the result of infertility, may be at increased risk of developing PTSD, one of the recognized postpartum psychiatric disorders. It is important to distinguish PTSD from postpartum depression, because treatment guidelines vary.

Journal Article↗
PubMed1996

[Implantation metastases following laparoscopic cholecystectomy in gallbladder carcinoma].

HISTORY AND CLINICAL FINDINGS: A 66-year-old woman was known to have had cholecystolithiasis for at least 4 years. Laparoscopic cholecystectomy was performed at another hospital where histological examination surprisingly revealed middle-grade differentiated carcinoma of the gall-bladder (pT2, G2). A nodular metastasis of the gall-bladder carcinoma was noted on the abdominal wall 3 months later and excised. Lymph-vessel carcinomatosis was already present. The patient again noticed a tumour in the right mid-abdomen and a further tumour was palpated in the epigastrium 5 months after the operation. INVESTIGATIONS: Laboratory and tumour-marker (CEA, CA 19-9) tests were unremarkable, while sonography and computed tomography were highly suspicious for abdominal wall metastases in the epigastrium and right mid-abdomen. TREATMENT AND COURSE: Both metastases were excised. Laparotomy revealed tumour recurrence in the old gall-bladder bed, as well as extensive peritoneal carcinoma. Two months after the operation she developed jaundice, caused by tumour compression of the choledochal duct. An expanding stent was inserted into the stenosed section of the duct. The patient died 13 months after the first operation from the underlying malignancy with multiple liver metastases and malignant ascites. CONCLUSIONS: Indications for minimally invasive surgery in malignant tumour should be narrowly defined. Because tumour seeding is possible after laparoscopic cholecystectomy with incidentally found carcinoma extensive re-excision should be performed.

Abdominal Muscles↗