Primary gastrointestinal B-cell lymphoma. A clincopathological and immunohistochemical study of 61 cases with an evaluation of prognostic parameters

We hereby present a retrospective clinicopathological and immunohistochemical study of surgically resected primary gastrointestinal (GI) lymphoma with an analysis of parameters of potential prognostic relevance. From a larger series of 144 cases of primary GI lymphomas, we chose 61 cases with sufficient clinical follow-up (mean 60, range 1-219 months), classified either as extranodal marginal zone B-cell lymphoma of MALT type (MALT lymphoma) or diffuse large B-cell lymphoma (DLBCL), after having excluded other subtypes. In addition to conventional clinical and morphological parameters, the expression levels of Ki-67 (MIB-1), bcl-2 and p53 were evaluated for prognostic significance. Twenty-one (34.4%) cases were classified as pure low grade marginal zone B-cell lymphoma of MALT type, 12 (19.7%) cases as low grade MALT lymphoma with a high grade component (mixed type), and 28 (45.9%) cases as primary extranodal DLBCL. Most of the lymphomas (53/61; 86.9%) were localized in the stomach, 3 (4.9%) in the small bowel, 3 (4.9%) multifocal in both stomach and small intestine and 2 (3.3%) in the large bowel. MIB-1 expression in more than 30% of tumor cells was detected in 42 (68.6%), bcl-2 expression in 20 (32.8%) and p53 accumulation in more than 10% of neoplastic cells in 16 (26.2%) lymphomas. Both high Ki-67 expression and p53 accumulation were more prevalent in the DLBCL. 30 (49%) patients showed lymph node involvement at surgery, 14 (23%) patients suffered tumor recurrence, and 24 (38.5%) died during the follow-up period. Tumor recurrence occurred primarily in patients who had presented lymph node involvement (9/14, 64.3%). The 5-year survival rate was 66.1% for all patients. Important prognostic factors for overall survival were tumor stage (p < .004) and p53 accumulation (p < .05) in univariate analysis, and tumor stage in multivariate analysis (p < .001). Although p53 accumulation did not reach statistical significance in our small study group, it may be both important in the transformation of low grade MALT lymphoma and an indicator for aggressive behavior in high grade tumors.

Distribution of the major gamma-aminobutyric acid(A) receptor subunits in the basal ganglia and associated limbic brain areas of the adult rat

Within the basal ganglia, gamma-aminobutyric acid (GABA) exerts a fundamental role as neurotransmitter of local circuit and projection neurons. Its fast hyperpolarizing action is mediated through GABA(A) receptors. These ligand-gated chloride channels are assembled from five subunits, which derive from multiple genes. Using immunocytochemistry, we investigated the distribution of 12 major GABA(A) receptor subunits (alpha1-5, beta1-3, gamma1-3, and delta) in the basal ganglia and associated limbic brain areas of the rat. Immunoreactivity for an additional subunit (subunit alpha6) was not observed. The striatum, the nucleus accumbens, and the olfactory tubercle displayed strong, diffuse staining for the subunits alpha2, alpha4, beta3, and delta presumably located on dendrites of the principal medium spiny neurons. Subunit alpha1-, beta2-, and gamma2-immunoreactivities were apparently mostly restricted to interneurons of these areas. In contrast, the globus pallidus, the entopeduncular nucleus, the ventral pallidum, the subthalamic nucleus, and the substantia nigra pars reticulata revealed dense networks of presumable dendrites of resident projection neurons, which were darkly labeled for subunit alpha1-, beta2-, and gamma2-immunoreactivities. The globus pallidus, ventral pallidum, entopeduncular nucleus, and substantia nigra pars reticulata, all areas receiving innervations from the striatum, displayed strong subunit gamma1-immunoreactivity compared to other brain areas. In the substantia nigra pars compacta and in the ventral tegmental area, numerous presumptive dopaminergic neurons were labeled for subunits alpha3, gamma3, and/or delta. This highly heterogeneous distribution of individual GABA(A) receptor subunits suggests the existence of differently assembled, and presumably also functionally different, GABA(A) receptors within individual nuclei of the basal ganglia and associated limbic brain areas.

Reconstruction of large soft tissue defects in the inguinal and suprapubic region using a variety of flaps

OBJECTIVES

To review a variety of optional reconstructive procedures for the surgical management of extensive soft tissue defects after radically curative or palliative resection of tumors, scars or damaged tissue in the inguinal and suprapubic region.

METHODS

Clinical experience with 24 pedicled or free flaps applied in 20 patients to cover extensive defects with exposed underlying structures are presented. The proper selection of flap was based on the individual requirements of each patient taking into consideration age, cause, size, shape and deepness of the defect, donor site morbidity, the patient's general condition and the situation of vascular supply of the adjacent regions.

RESULTS

A high success rate with a moderate rate of only minor complications leads to a reasonably short hospital stay with a definitive defect cover. In the cases of palliation a distinct improvement in quality of survival could be achieved.

CONCLUSIONS

After extensive or radical resection almost every defect may be sufficiently covered in a single stage. The inferior epigastric flap serves as the most versatile flap, but nevertheless appropriate selection of the reconstructive technique must be adapted considering the complexity of the illness and defect in each individual case.

Is there a dysplasia-carcinoma sequence in rat gastric remnant?

Epithelial dysplasia in the gastric remnant is generally considered to have a positive predictive value for malignancy. Whether dysplasia progresses to carcinoma or whether both just have a common origin, is still a matter of controversy. The aim of the present study in rats was to investigate the natural history of epithelial lesions in the gastric remnant. A gastric resection was carried out in 50 male Wistar rats. Postoperatively the animals received N-methyl-N'-nitro-N-nitrosoguanidine orally. Gastroscopy was carried out monthly and biopsies were taken for histologic evaluation. The rats were killed after 12 months or if gastric cancer was found on gastroscopy. Twenty-four rats died postoperatively and were excluded from the study. A total of 228 gastroscopies was performed in the remaining 26 animals; 24 animals developed dysplastic lesions during the follow-up period. The rate of development of gastric cancer within one month increased with the stage of dysplasia at the previous examination (3% for mild, 48% for moderate, 100% for severe dysplasia). There was a strong correlation between the time period following gastric resection and grade of dysplasia and between the grade of dysplasia and development of cancer. Our study demonstrates that gastric stump cancer in rats develops from dysplastic lesions. A dysplasia-carcinoma sequence can therefore be assumed.

Dephosphorylation of tyrosine hydroxylase by brain protein phosphatases: a predominant role for type 2A

Extracts from rat corpus striatum, or striatal proteins resolved by chromatography on DE-52, were tested for protein phosphatase activity using tyrosine hydroxylase, phosphorylated by cAMP-dependent protein kinase, as substrate. The predominant dephosphorylating activity was independent of divalent cations and was inhibited by low concentrations (100 nM) of okadaic acid, defining the phosphatase as type 2A. Phosphatase type 2C (Mg2+ and Mn2+ stimulated) was evident in the presence of okadaic acid but at a level of approximately 10% of type 2A activity. Phosphatase 2B (Ca2+ and calmodulin dependent) mediated dephosphorylation of tyrosine hydroxylase was not apparent. The dephosphorylation of [32P]-tyrosine hydroxylase was not modulated by tetrahydrobiopterin, ATP, or GTP. These results indicate that tyrosine hydroxylase which has been phosphorylated by cAMP dependent protein kinase is dephosphorylated predominantly by phosphatase type 2A in brain, and the activity of this phosphatase is not modulated by pteridines or nucleotides.