Brain tissue microarrays in dementia research: White matter microvascular pathology in Alzheimer's disease

Tissue microarrays (TMA) consist of up to 1000 cylindrical tissue cores from different donor paraffin blocks relocated into one recipient block, allowing for efficient histopathological studies by fluorescence in situ hybridization, RNA in situ hybridization or immunohistochemistry. On the background of the increasing interest of the TMA technique in cancer research and the suggestion of its application also in studies of non‐neoplastic intracranial disorders, the technique was applied to pathologic white matter in AD brains. Eight cases with AD and concomitant white matter pathology were neuropathologically diagnosed on whole brain coronal slides. The TMA technique was used to grade severity of white matter pathology and to quantify small vessels with traditional staining and immunohistochemical markers. These measurements were compared with the whole brain neuropathological assessment. The technique produced good results with preserved tissue structures as confirmed by the whole brain evaluation. Severity of white matter pathology evaluated on the TMA cores correlated negatively with small vessel quantities, and statistically significant differences in vessel quantities paralleled different grades of white matter pathology. It is concluded that the TMA technique could be further utilized in studies of dementing disorders, and may have its advantages in large, clinically well‐characterized materials (e.g. in quantitative mapping of white matter changes).     

Tissue expression of the tumour associated antigen CA242 in benign and malignant pancreatic lesions. A comparison with CA 50 and CA 19-9

The expression of a novel tumour associated antigen CA 242, defined by the monoclonal antibody C 242, was studied by immunoperoxidase staining in formalin-fixed, paraffin-embedded tissue sections from normal pancreata, pancreata with pancreatitis and benign and malignant pancreatic neoplasms. The antigenic determinant of the C 242 antibody is a sialylated carbohydrate structure, related but chemically different from tumour marker antigens CA 19-9 and CA 50. Thirty-eight of 41 (93%) well to moderately differentiated ductal adenocarcinomas of the pancreas and all cystadenocarcinomas were positive for CA 242. The staining was most intense in the apical border of the cells, and in the intraluminal mucus. Only two out of seven poorly differentiated adenocarcinomas stained, and the number of positive cells was smaller than in well differentiated carcinomas. Only occasional cells were stained in one out of five anaplastic carcinomas. Part of large ducts were positive in 91% (21/23) specimens of chronic pancreatitis. In acute pancreatitis small terminal ducts, centro-acinar cells and some large ducts stained for CA 242. In normal pancreas only a few small terminal ducts were CA 242 positive. Carcinomas always stained more strongly for CA 242 than normal pancreatic tissue adjacent to the carcinoma. The results of CA 242 are compared with those of tumour marker antigens CA 50 and CA 19-9. Serum CA 242 levels were determined in 23 of the patients with pancreatic cancer using a fluoroimmunoassay. Fifteen (65%) patients had an elevated value. There was no clear-cut correlation between the serum levels and the immunohistochemical expression of the CA 242 antigen. The expression of CA 242 in pancreatic tissue resembles that of CA 50 and is similar to CA 19-9. The antigen is expressed in serum of many patients with pancreatic cancer and, therefore, is a potential candidate for a serum tumour marker.     

Primary lymphocytes as predictors for species differences in cytotoxic drug sensitivity.

Several in vitro methods have been suggested to predict drug-induced haematotoxicity and species differences; the most commonly used being the clonogenic CFU-GM assay. The aim of the current study was to evaluate whether primary lymphocytes from peripheral blood, assayed with a short-term non-clonogenic assay, could be used to detect species differences in drug sensitivity, and offer an alternative to the CFU-GM assay. The effect of 17 different cytotoxic drugs on lymphocytes from human, dog, rat and mouse was evaluated. A higher sensitivity of human than mouse lymphocytes was seen for topotecan and for 3 of 5 antimetabolites tested. Clear species specificity was also seen for the proteasome inhibitor bortezomib where rodent cells were 50-300 times less sensitive than human cells. Good agreement between our data and published CFU-GM data was observed, suggesting that primary lymphocytes may be a useful model for species difference screening in drug development.     

Tension leads to increased neutrophil accumulation and decreased laparotomy wound strength

Wound margin strength was measured immediately after and at 72 hours after median laparotomy in rats. The laparotomy wound was sutured with or without tension, and wound margin strength was measured as breaking strength with the sutures in situ. In wounds sutured without tension, no decrease in breaking strength was observed at 72 hours; in rats sutured with tension, breaking strength decreased by 77%, and in almost half of the animals the sutures cut through. There was markedly increased accumulation of neutrophil leukocytes around the sutures in the tension group, as indicated by increased tissue myeloperoxidase activity. The decrease in breaking strength was abolished by treatment with an inhibitor of the collagen-degrading proteinases of the neutrophils (the soybean trypsin inhibitor). Although the decrease in breaking strength should be due to collagenolysis, there were no changes in collagen content or solubility around the sutures, indicating that the changes in collagen were too delicate to be revealed by the methods used. We conclude that the decrease in breaking strength was caused by the neutrophils.     

A tobacco quit and win model in the Stockholm cancer prevention programme.

The main objective of the Stockholm Cancer Prevention Programme (SCPP) is to reduce cancer incidence and mortality among the 1.6 million inhabitants in Stockholm county by reducing risk factors particularly related to lifestyle. The objective of the SCPP's tobacco action programme is to reduce the number of adult daily users of tobacco (including oral snuff) to 20% by the year 2000. In 1988, a nationwide Quit and Win contest was conceived as part of this long-term programme. The contest recruited nearly 13,000 participants or 0.6% of the daily tobacco users in Sweden over the age of 16 years. More than 60% of the participants were recruited from Stockholm county. This corresponds to 1.9% of the daily tobacco users in Stockholm county compared with 0.3% in the rest of Sweden. The pharmacies and the public health services organizations were the principal distributors of contest entry forms. Sixty-two percent of the men and 59% of the women were tobacco free one month after the contest, and after 6 months the corresponding figures were 30 and 25%, respectively.     

Liver metabolic effects of intestinal shock and naloxone treatment in the rat

The liver metabolic response of rats following a standardized intestinal shock, induced by applying a pressure of 120 cm water on the mesenteric vessels for 60 min, was studied. Immediately prior to the release of the pressure on the vessels saline or naloxone was given either as a single injection or as a continuous infusion. After the reperfusion of the intestine no early disturbances in liver metabolism were found as evidenced from the ATP, glucose and lactate levels in liver biopsies taken 15 min following reflow. Within 60 min of reflow reduction of ATP and increases of glucose and lactate levels occurred. There were no major hemodynamic or liver metabolic differences between saline- and naloxone-treated shocked rats. When saline or naloxone was given as a continuous infusion, the changes in liver metabolism were, however, less severe than those observed in the single injection situation pointing toward a non-specific effect of volume replacement rather than a blockade of opioid receptors. Hepatic hypoxia and/or cellular effects of "shock factors" could be mechanisms of pathophysiologic importance for the disturbed liver metabolism in this shock model.     

Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability

X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG repeat expansion in the first exon of the androgen receptor (AR) gene. Disease-associated alleles (37-66 CAGs) change in length when transmitted from parents to offspring, with a significantly greater tendency to shift size when inherited paternally. As transgenic mice carrying human AR cDNAs with 45 and 66 CAG repeats do not display repeat instability, we attempted to model trinucleotide repeat instability by generating transgenic mice with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions in their genomic context. Studies of independent lines of AR YAC transgenic mice with CAG 45 alleles reveal intergenerational instability at an overall rate of approximately 10%. We also find that the 45 CAG repeat tracts are significantly more unstable with maternal transmission and as the transmitting mother ages. Of all the CAG/CTG repeat transgenic mice produced to date the AR YAC CAG 45 mice are unstable with the smallest trinucleotide repeat mutations, suggesting that the length threshold for repeat instability in the mouse may be lowered by including the appropriate flanking human DNA sequences. By sequence-tagged site content analysis and long range mapping we determined that one unstable transgenic line has integrated an approximately 70 kb segment of the AR locus due to fragmentation of the AR YAC. Identification of the cis - acting elements that permit CAG tract instability and the trans -acting factors that modulate repeat instability in the AR YAC CAG 45 mice may provide insights into the molecular basis of trinucleotide repeat instability in humans.      

Tenascin-C in primary Merkel cell carcinoma

BACKGROUND/AIMS: Merkel cell carcinoma (MCC) is a rare malignant cutaneous neuroendocrine tumour that mostly affects the elderly. It shows rapid progression of the primary tumour, together with a vertical growth pattern into the underlying subcutaneous tissue. Metastatic dissemination to regional lymph nodes is early and frequent. Tenascin-C (Tn-C) is a large extracellular matrix glycoprotein that is expressed in various benign and malignant processes. Expression of Tn-C is also associated with invasion and cellular proliferation, and is often downregulated in fully evolved advanced carcinomas. In previous studies, Tn-C expression correlated with prognosis in tumours of different origin. METHODS: Immunohistochemistry was used to investigate the expression of Tn-C in 25 MCC specimens and to evaluate the prognostic importance of this glycoprotein. RESULTS: Seventeen samples expressed Tn-C. Staining was mainly seen in the invasion borders and within the connective tissue septae inside the tumours. The expression of Tn-C correlated significantly with large tumour size. There was also frequent expression of Tn-C in primary tumours with metastatic dissemination. Most of the Tn-C negative samples were of small size. CONCLUSIONS: Tn-C expression seems to increase with tumour size and malignant behaviour. Expression was slightly enhanced in tumours with high proliferative indices. Expression is seen mainly in areas of invasive growth and, in this respect, resembles that of other invasive tumours.     

Cryopreservation of human oocytes: a review of current problems and perspectives

It is well recognized that the ability to cryopreserve unfertilizedhuman oocytes would make a significant contribution to infertilitytreatment. However, despite considerable interest, very fewsuccessful pregnancies have arisen from cryopreserved oocytesafter thawing, insemination and transfer of the subsequent embryo.The reasons for this lack of progress may well result from adearth of information on how the various biophysical changesduring a cryopreservation regimen affect human oocyte function.Recently, fundamental studies on the effects of cooling, membranepermeability, cryoprotectant addition and ice formation havebeen performed on human oocytes by a number of groups, and theseform the basis of the current review. It is likely that successfulhuman oocyte cryopreservation will only follow once these factorsare fully understood, but the existing base of knowledge shouldprovide a platform for further improvements in the techniquescurrently employed.