Pancreatic mucinous noncystic (colloid) carcinomas and intraductal papillary mucinous carcinomas are usually microsatellite stable.

Pancreatic mucinous noncystic (colloid) carcinomas (MNCC) differ from the usual ductal adenocarcinomas in their mucin expression profile and share with many extrapancreatic mucinous carcinomas the expression of MUC2. Because mucinous carcinomas are frequently associated with mutations of the DNA mismatch repair genes, causing them to exhibit the so-called mutator phenotype, we decided to investigate whether MNCCs of the pancreas are characterized by microsatellite instability (MSI). Twelve carcinomas with a mucinous phenotype (8 mucinous noncystic carcinomas, 3 intraductal papillary-mucinous carcinomas with an invasive muconodular component, and 1 ductal adenocarcinoma with an extensive mucinous noncystic component) and 11 ductal adenocarcinomas were immunostained with monoclonal antibodies to the mismatch repair gene products hMLH1, hMSH2, and hMSH6. For MSI analysis, DNA was isolated from microdissected tissue, and five primary microsatellites (BAT 25, BAT 26, D5S346, D17S250, and D2S123) were analyzed. MSI was diagnosed in case a novel allele was found, compared with the normal tissue. The criterion for LOH was a 75% signal reduction. All carcinomas tested exhibited nuclear expression of mismatch repair gene products, except for one MNCC that also showed MSI at the molecular level. The data suggest that pancreatic carcinomas with a mucinous phenotype (MUC2+/MUC1-) do not appear to normally exhibit mutations in the mismatch repair genes and therefore differ in their carcinogenesis from those in other organs.     

Direct mapping of MHC class II epitopes

Despite technical improvements, the mapping of MHC class II epitopes within complex antigens by genetic or biochemical methods is still laborious and expensive. Here, we describe a simple and fast procedure to directly map T helper cell epitopes within known antigens by bacterial expression cloning. Short antigenic fragments, created by digestion of the coding sequence of the antigen with frequently cutting restriction enzymes, are randomly ligated to the coding sequence of GFP in a bacterial expression vector. Bacteria expressing antigen-GFP fusion proteins are then fed directly to MHC II+ antigen-presenting cells and probed with antigen-specific T cells. Bacterial colonies recognized by T cells are expanded, and the antigenic fragments identified by plasmid extraction and sequence analysis. This direct epitope identification (DEPI) approach offers several advantages. First, bacterial colonies expressing the antigen in frame with GFP are easily detectable by virtue of their green appearance and thereby reduce the screening effort significantly. Second, short antigenic peptides normally unstable in bacteria are highly expressed when fused to GFP. Third, the uniformly high level of expression of short antigenic peptides fused to GFP permits the identification of epitopes even within proteins which are difficult to express in bacteria. Furthermore, by fusing double-stranded oligonucleotides to the GFP gene, crucial amino acids within T cell epitopes may be defined. Thus, this method not only facilitates the identification of T cell epitopes, but also makes it possible to assess the role of individual amino acids for MHC binding or T cell recognition.     

Effect of methoxime combined with anticholinergic, anticonvulsant or anti-HCN drugs in tabun-poisoned mice

The effect of methoxime combined with a) atropine, b) benactyzine, c) atropine and natrium thiosulphate, d) atropine and diazepam on antidotal treatment effectiveness was studied in tabun-poisoned mice. In addition, the influence of pretreatment consisiting of pyridostigmine, benactyzine and trihexyphenidyle (PANPAL) administered 2 hours before tabun intoxication on the treatment effectivity of methoxime combined with e) atropine or f) benactyzine was tested. The most efficacious therapeutic mixture in non-pretreated mice was methoxime, atropine and diazepam. Natrium thiosulphate did not significantly increase neither decrease the antidotal treatment efficacy in comparison with methoxime and atropine alone. Pretreatment with PANPAL significantly decreased tabun toxicity (nearly 4 times in methoxime and benactyzine combination and more than 4 times in atropine and methoxime mixture). The present study demonstrates that the tabun toxicity in mice is more effectively reduced when PANPAL prophylactically is administered than in case of treatment with methoxime and cholinergic drug alone. We established that anticholinergic drug option in the therapeutic mixture of methoxime and anticholinergic drug did not cause the difference in the antidotal treatment effectivities.     

Translocation (6;9)(p23;q34) in acute nonlymphocytic leukemia: Three new cases

Several recent reports have described cases of acute nonlymphocytic leukemia with a unique chromosome translocation, t(6;9)(p23;q34). We have studied three additional patients who have acute nonlymphocytic leukemia and t(6;9)(p23;q34). Our findings provide additional support for the suggestion that this translocation is yet another distinct cytogenetic abnormality associated with myeloproliferative disorders.     

The dorsal lingual epithelium of Rhinoclemmys pulcherrima incisa (Chelonia, Cryptodira)

This study employed light microscopic (LM), scanning electron microscopic (SEM), and transmission electron microscopic (TEM) methods to provide detailed morphological information on the histological and ultrastructural features of the dorsal tongue epithelium of Rhinoclemmys pulcherrima incisa. SEM revealed columnar papillae laterally, as well as papillae, which tend to have a ridge-like appearance in the center of the tongue. LM and TEM showed three different zones of lingual epithelium: a stratified apical area with serous cells at the top of the papillae, a stratified lateral area with both serous and mucus cells, and an unstratified glandular area consisting of distinct glandular ducts with mucus cells. Comparison with morphological data from other turtles shows that the lingual epithelial structure in R. p. incisa is in accordance with that observed for other generalized omnivores which prefer a terrestrial lifestyle, thus matching the ecological information about this species.     

Infrared spectra and crystallinity of isotactic poly(methyl methacrylate) and of its deuterated analogues

Infrared spectra of partially crystalline and amorphous samples of isotactic poly(methyl methacrylate) (i-PMMA), poly[methyl (α,α,α-²H₃)methacrylate] (i-PMMA-α-CD₃), poly-[(²H₃)methyl methacrylate] (i-PMMA-OCD₃), and poly[(²H₃)methyl (α,α,α,2,2-²H₅)methacrylate] (i-PMMA-D₈) were measured. Infrared spectra of the pure crystalline forms of these substances were obtained by digital separation. It was found that in acetonitrile, CDCl₃, and toluene solutions, i-PMMA has the same conformational structure as in the amorphous state; conformational structures of crystalline i-PMMA are not present in the solutions in measurable amounts.     

Infiltrating mononuclear cells in human breast carcinoma: predominance of T4+ monocytic cells in the tumor stroma

Frozen sections of 52 breast carcinomas were examined for the presence and nature of a leukocytic infiltrate. The number of "common leukocyte (T200-) antigen"-bearing cells was remarkably high in the stromal compartment of the carcinomas, whereas the tumor foci themselves were usually infiltrated only sparsely. Approximately 80% of these T200+ stromal cells carried the myelomonocyte lineage-associated antigens M-M522 and 63D3 and exhibited "non-specific esterase" activity. More than 2/3 of the stromal monocytic cells expressed the T4 antigen as verified by monoclonal antibodies (MAbs) directed against different T4-associated epitopes. A T-cell analysis showed that T4+ cells clearly outweighed the total number of T cells as defined by anti-T3 and anti-TII antibodies. In addition, a correlation became apparent between the HLA-DR phenotype and the T lymphocyte content of tumor cell areas in the sense that densely infiltrated tumor areas were invariably HLA-DR+.     

Phenotypic dynamics of tumor progression in human malignant melanoma

The phenotypic changes in human melanoma cells during the course of tumor progression were studied with monoclonal antibodies (MAbs) against the melanoma-associated antigens (MAA) M.2.2.4, H.2.8.10, K.1.2, A.1.43, and A.10.33, and HLA-(A,B,C and D). Cryostat sections of 172 primary melanomas of the skin, 157 melanoma metastases and 56 nevi were investigated with an indirect immunoperoxidase method. Phenotypic heterogeneity was observed within lesions at all stages, and also within different tumors of the same patients. Despite this heterogeneity, principles of antigen expression were found. From the reaction pattern of MAbs, the following classifications of antigens were derived: "constitutive" markers of nevomelanocytic cells (M.2.2.4 and H.2.8.10) were found expressed over a wide range of local and systemic tumors. One MAA, K.1.2 (Suter et al., 1985), that declines with progression of melanoma, was classified as an "early" antigen, whereas MAA that appear in primary melanoma in proportion to invasiveness, and which are expressed in metastases of lymph nodes and visceral organs (A.1.43, and A.10.33), were classified as "late" markers of tumor progression. HLA-antigens were classified as "intermediate" markers, HLA-A,B,C, as an "early-intermediate", and HLA-DR as a "late-intermediate" marker. The occurrence of class II HLA, A.1.43-, and A.10.33-positive tumor cells in primary melanoma indicates a high metastatic potential of tumors, independent of tumor thickness. The data show that local and systemic progression of melanoma is associated with qualitative changes in tumor cells which can be recognized by MAbs.     

Series dead space volume assessed as the mean value of a distribution function

Series dead space (VdS) is assumed to be represented by that volume exhaled until alveolar gas is observed. Phase II of the single breath CO₂-diagram contains the (flow, concentration and sequence weighted) distribution off all stationary interfaces (SI) expired before phase III. We describe a new method to estimate the mean value of VdS based on the differentiation of phase II. This approximation of VdS is called the Pre Interface Expirate (PIE) and is compared in this study with the integrative approach of Langley. Tidal volume (Vt) and PEEP were varied from 71 to 123% and from 0 to 6 cmH₂O respectively.The estimation of VdS by differentiation of phase II (PIE) shows excellent reproducibility and depends only on phase II — not on phase III and IV as does VdS-Langley. PIE does not depend on Vt and PEEP per se but reflects the distension of convective airways due to elevated end-inspiratory airway pressure.Our results confirm the predictions of Paiva's model calculations in that the size of VdS is determined by the distension of airways rather than by the altered position of the SI.