Low myocardial transcript variant alt-a of cyclin dependent kinase inhibitor p21 expression differentiates hypothermia from cardiac/respiratory causes of death

Gene expressions in the myocardium have been shown to vary between different causes of death, which can be utilized in the recognition of varied processes. Our previous work with a limited number of cases showed a high messenger ribonucleic acid expression of the transcript variant alt-a of cyclin dependent kinase inhibitor p21 (p21 alt-a) in chronic cardiac ischemia deaths and a low expression in hypothermia deaths and acute myocardial ischemia deaths. In present work, p21 alt-a expression in the myocardium of human cadavers was calculated using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as reference gene. In this collection of 143 samples, the p21 alt-a expression was significantly lower in hypothermia than in chronic cardiac ischemic heart disease with (P < .001) or without (P < .001) acute myocardial infarction and in other cardiac and respiratory disease deaths (P < .000). Chronic ischemic heart disease in hypothermia cases did not increase the expression. The p21 alt-a expression did not correlate with postmortem interval, quality of RNA or with the age of the deceased. The p21 alt-a referenced to GAPDH expression in cadaver myocardium has apparent potential as a marker distinguishing between hypothermia and cardiac/respiratory diseases as causes of death.

RNU6B, a frequent reference in miRNA expression studies, differentiates between deaths caused by hypothermia and chronic cardiac ischemia

Here, we tested the usefulness of small non-coding RNAs as references in quantitative RT-PCR expression analyses in hypothermia and chronic cardiac ischemia as the primary causes of death. Cq values of RNU6B, SCARNA17, SNORD25, and SNORA73A were determined from human cadaver samples of hypothermia and cardiac deaths. Average Cq values of RNU6B were higher in hypothermic and average SCARNA17 Cq values in chronic ischemic samples, but no difference in SNORD25 and SNORA73A Cq values could be seen between the groups. RNU6B expression levels were calculated using SNORD25, SNORA73A, and their combination as the reference in normalization. Expression of RNU6B, a widely used reference, was found to be significantly lower in hypothermia than in chronic cardiac ischemia. In these conditions, RNU6B is a useful marker differentiating hypothermia deaths from chronic ischemic heart disease deaths, but not a valid reference for normalization in expression studies.

Hypothermia and rewarming induce gene expression and multiplication of cells in healthy rat prostate tissue

Prostate cancer has been extensively studied, but cellular stress responses in healthy prostate tissue are rarely investigated. Hypothermia is known to cause alterations in mRNA and protein expressions and stability. The aim of this study was to use normal rat prostate as a model in order to find out consequences of cold exposure and rewarming on the expressions of genes which are either members or functionally/structurally related to erythroblastic leukemia viral oncogene B (ErbB) signaling pathway. Relative mRNA expressions of amphiregulin (AMR), cyclin D1 (CyD1), cyclin-dependent kinase inhibitor 1A (p21), transmembrane form of the prostatic acid phosphatase (PAcP), thrombomodulin (TM) and heat shock transcription factor 1 (HSF1) in rat ventral prostate were quantified in mild (2 or 4.5 h at room temperature) and severe (2 or 4.5 h at +10°C) hypothermia and in rewarming after cold exposure (2 h at +10°C followed by 2 h at room temperature or 3 h at +28°C). AMR protein level, apoptotic Bcl-2 associated X protein to B-cell CLL/lymphoma 2 (Bax/Bcl-2) mRNA ratio and proliferative index Ki-67 were determined. 4.5-h mild hypothermia, 2-h severe hypothermia and rewarming increased expression of all these genes. Elevated proliferation index Ki-67 could be seen in 2-h severe hypothermia, and the proliferation index had its highest value in longer rewarming with totally recovered normal body temperature. Pro-apoptotic tendency could be seen in 2-h mild hypothermia while anti-apoptosis was predominant in 4.5-h mild hypothermia and in shorter rewarming with only partly recovered body temperature. Hypothermia and following rewarming promote the proliferation of cells in healthy rat prostate tissue possibly via ErbB signaling pathway.

Urinary thrombomodulin and catecholamine levels are interrelated in healthy volunteers immersed in cold and warm water

Severe hypothermia has been shown to influence the levels of catecholamines and thrombomodulin, an endothelial protein essentially involved in the regulation of haemostasis and inflammation. A link between thrombomodulin and catecholamines during cold exposure has also been previously suggested. The aim of this study was to assess the influence of short-term cold exposure without hypothermia on catecholamines and the circulating and urinary thrombomodulin levels. Seven healthy male subjects were immersed in cold water (+10°C) for 10 minutes followed by a 20-minute immersion in +28°C water. Warm water immersion was performed separately for each subject (+30°C for 30 minutes). Thrombomodulin and catecholamine concentrations were measured from pre- and post-immersion (up to 23 hours) samples. In urine, the thrombomodulin level correlated strongly with adrenaline (ρ = 0.806) and noradrenaline (ρ = 0.760) levels. There were no significant differences in thrombomodulin levels between immersion temperatures. Post-immersion urinary thrombomodulin levels were significantly lower than the pre-immersion level at both immersion temperatures. Median concentrations of plasma noradrenaline and urinary adrenaline were higher after exposure to +10°C than to +30°C. Thus, further evidence of the association between thrombomodulin and catecholamines was gained in a physiologically relevant setting in humans. Additionally, it is evident that a short-term cold exposure was not able to elicit changes in the thrombomodulin levels in a follow-up period of up to 23 hours. These findings provide further understanding of the physiological responses to cold during immersion, and of the potential influence of stress on haemostatic and inflammatory responses.

Changes in cardiac thrombomodulin and heat shock transcription factor 1 expression and peripheral thrombomodulin and catecholamines during hypothermia in rats

Effects of hypothermia and rewarming on thrombomodulin, catecholamines and heat shock transcription factor 1 (HSF1) were studied in rats. The aims of this study were to clarify whether cold stress, under anesthesia, is sufficient to change levels of thrombomodulin in healthy endothelium and in the circulation and whether adrenaline, noradrenaline and HSF1 could act as regulators in the process. Rats were divided into control, mild hypothermia (2 and 4.5 hours at + 21 °C; MH1, MH2), severe hypothermia (2 and 4.5 h at + 10 °C; SH1, SH2) and two rewarming groups (2 h at + 10 °C followed by 2 h at + 21 °C or 3 h at + 28 °C; SHW1, SHW2) (n = 15/group, except n = 6 in MH1). Fentanyl-fluanisone-midazolam was used as anesthetic. Low levels of thrombomodulin in plasma and myocardial arterioles/venules measured by ELISA and immunohistochemistry were associated with significant increase of thrombomodulin transcript level in SH1 rats analyzed by quantitative PCR. Plasma adrenaline correlated negatively with the relative amount of myocardial thrombomodulin transcripts and positively with plasma thrombomodulin in SH. Transcript levels of thrombomodulin and HSF1 correlated strongly (r = 0.83; p < 0.001) in SH. Plasma/urine ratio of thrombomodulin and plasma adrenaline (r = 0.87; p = 0.005) or noradrenaline (r = 0.78; p = 0.023) were strongly correlated in SHW1 rats. Hence, cellular and soluble levels of thrombomodulin are modified by cold stress in healthy rats, possibly via catecholamines and HSF1.

Increased type I collagen synthesis in victims of sudden cardiac death due to idiopathic myocardial fibrosis

AIMS

Idiopathic myocardial fibrosis (IMF) was observed to be the most prevalent autopsy finding in the victims of sudden cardiac death (SCD) under the age of 40 years in the FinGesture cohort. To elucidate further the mechanisms of IMF, we examined the collagen composition from the myocardial samples taken from the victims of IMF-associated SCD.

METHODS

Eighteen cases with IMF as a cause of death, confirmed by autopsy, were selected for the analysis. Controls (n = 27) included were cases in whom no cardiac or non-cardiac disease could be found as a cause of unexpected death at autopsy. In addition to conventional histological examination, immunohistochemical staining of procollagens I and III (PINP and PIINP), mature collagen III (IIINTP), and the cross-linked collagen I degradation product (ICTP) were performed.

RESULTS

Increased accumulation of PINP was observed in the fibrotic tissue of the IMF cases in comparison with control samples. In contrast, type III collagen was not as frequently expressed in the fibrotic areas.

CONCLUSION

Myocardial accumulation of PINP in the victims of IMF-associated SCD indicates increased type I collagen synthesis. Future studies on the role of circulating type I collagen biomarkers are needed to study further the implications of the described association.

O-glycosylation regulates LNCaP prostate cancer cell susceptibility to apoptosis induced by galectin-1

Resistance to apoptosis is a critical feature of neoplastic cells. Galectin-1 is an endogenous carbohydrate-binding protein that induces death of leukemia and lymphoma cells, breast cancer cells, and the LNCaP prostate cancer cell line, but not other prostate cancer cell lines. To understand the mechanism of galectin-1 sensitivity of LNCaP cells compared with other prostate cancer cells, we characterized glycan ligands that are important for conferring galectin-1 sensitivity in these cells, and analyzed expression of glycosyltransferase genes in galectin-1-sensitive, prostate-specific antigen-positive (PSA(+)) LNCaP cells compared with a galectin-1-resistant PSA(-) LNCaP subclone. We identified one glycosyltransferase, core 2 N-acetylglucosaminyltransferase, which is down-regulated in galectin-1-resistant PSA(-) LNCaP cells compared with galectin-1-sensitive PSA(+) LNCaP cells. Intriguingly, this is the same glycosyltransferase required for galectin-1 susceptibility of T lymphoma cells, indicating that similar O-glycan ligands on different polypeptide backbones may be common death trigger receptors recognized by galectin-1 on different types of cancer cells. Blocking O-glycan elongation by expressing alpha2,3-sialyltransferase 1 rendered LNCaP cells resistant to galectin-1, showing that specific O-glycans are critical for galectin-1 susceptibility. Loss of galectin-1 susceptibility and synthesis of endogenous galectin-1 has been proposed to promote tumor evasion of immune attack; we found that galectin-1-expressing prostate cancer cells killed bound T cells, whereas LNCaP cells that do not express galectin-1 did not kill T cells. Resistance to galectin-1-induced apoptosis may directly contribute to the survival of prostate cancer cells as well as promote immune evasion by the tumor.

Theoretical investigations of prostatic acid phosphatase

The phosphotyrosyl protein phosphatase activity of prostatic acid phosphatase (PAP) has been well established. It has also been suggested that PAP partly regulates the activity of growth factor receptors by dephosphorylating the autophosphorylysable tyrosines in them. We studied the binding of the peptides from epidermal growth factor receptor (EGFR) and its homolog (ErbB-2), corresponding to their autophosphorylation sites, to PAP using theoretical modeling and molecular dynamics (MD) simulation methods. Nine different peptides, each with a phosphotyrosine residue, were docked on human PAP. The binding energies of these peptide-PAP complexes were calculated theoretically and compared to experimentally obtained affinities. The peptide Ace--DNLpYYWD--NH2 from ErbB-2(1197-1203) showed the most favorable free energy of binding when estimated theoretically. The results demonstrate that the presence of another tyrosine residue proximate to C-terminal of autophosphorylysable Tyr enhances the binding affinity considerably. The presence of a bulky group instead prevents the binding, as is observed in case of peptide Ace--NLYpYWDQ--NH2 which failed to bind, both in theoretical calculations and experiments. Thus we demonstarted that PAP could potentially bind to EGFR and Erbb-2 and dephosphorylate them. Thus it could be involved in the regulation of the function of such receptors. In addition, complexes of a peptide from AngiotensinII and phosphotyrosine(pY) with human PAP were also modeled. The effects of different protonation states of the titratable active site residues on ligand (pY) binding have also been investigated. For a favorable binding His12 and Asp258 should be neutral, His257 should be positively charged and the phosphate group of the ligand should be in PO(4) (3-) state. Furthermore, the analysis of protein motion as observed during simulations suggests the loop-loop contact in the PAP dimer to be of importance in cooperativity.

Control of cell proliferation by steroids: the role of 17HSDs

Sex steroid hormone signaling regulates the development, growth, and functioning of the breast and the prostate and plays a role in the development and progression of cancer in these organs. The intracellular concentration of active sex steroid hormones in target tissues is regulated by several enzymes, including 17beta-hydroxysteroid dehydrogenases (17HSDs). Changes in the expression patterns of these enzymes may play a pathophysiological role in malignant transformation. We recently analyzed the mRNA expressions of the 17HSD type 1, 2, and 5 enzymes in about 800 breast carcinoma specimens. Both 17HSD type 1 and 2 mRNAs were detected in normal breast tissue from premenopausal women but not in specimens from postmenopausal women. The patients with tumors expressing 17HSD type 1 mRNA or protein had significantly shorter overall and disease-free survival than the other patients. The expression of 17HSD type 5 was significantly higher in breast tumor specimens than in normal tissue. Cox multivariate analyses showed that 17HSD type 1, tumor size, and estrogen receptor alpha (ERalpha) had independent prognostic significance. We developed, using a LNCaP prostate cancer cell line, a model to study the malignant transformation of prostate cancer and showed that androgen-sensitive LNCaP cells are transformed into neuroendocrine-like cells when cultured without androgens and, eventually into highly proliferating androgen-independent cells. We conducted Northern hybridizations and microarrays to analyze the gene expression during these processes. Substantial changes in the expressions of steroid metabolizing enzymes occurred during the transformation process. The variations in steroid-metabolizing enzymes during cancer progression may be crucial in the regulation of the growth and function of organs.

Enzymes as modulators in malignant transformation

Experimental data suggest that sex steroids have a role in the development of breast and prostate cancers. The biological activity of sex steroid hormones in target tissues is regulated by several enzymes, including 17beta-hydroxysteroid dehydrogenases (17HSD). Changes in the expression patterns of these enzymes may significantly modulate the intracellular steroid content and play a pathophysiological role in malignant transformation. To further clarify the role of 17HSDs in breast cancer, we analyzed the mRNA expressions of the 17HSD type 1, 2, and 5 enzymes in 794 breast carcinoma specimens. Both 17HSD type 1 and 2 mRNAs were detected in normal breast tissue from premenopausal women but not in specimens from postmenopausal women. Of the breast cancer specimens, 16% showed signals for 17HSD type 1 mRNA, 25% for type 2, and 65% for type 5. No association between the 17HSD type 1, 2, and 5 expressions was detected. The patients with tumors expressing 17HSD type 1 mRNA or protein had significantly shorter overall and disease-free survival than the other patients. The expression of 17HSD type 5 was significantly higher in breast tumor specimens than in normal tissue. The group with 17HSD type 5 overexpression had a worse prognosis than the other patients. Cox multivariate analyses showed that 17HSD type 1 mRNA, tumor size, and ERalpha had independent prognostic significance. Using an LNCaP prostate cancer cell line, we developed a cell model to study the progression of prostate cancer. In this model, androgen-sensitive LNCaP cells are transformed in culture conditions into more aggressive, androgen-independent cells. The model was used to study androgen and estrogen metabolism during the transformation process. Our results indicate that substantial changes in androgen and estrogen metabolism occur in the cells during the process. A remarkable decrease in oxidative 17HSD activity was seen, whereas reductive activity seemed to increase. Since local steroid metabolism controls the bioavailability of active steroid hormones of target tissues, the variations in steroid-metabolizing enzymes during cancer progression may be crucial in the regulation of the growth and function of organs.

Sex steroid hormone metabolism and prostate cancer

The growth and function of the prostate is dependent on androgens. The two predominant androgens are testosterone, which is formed in the testis from androstenedione and 5alpha-dihydrotestosterone, which is formed from testosterone by 5alpha-reductases and is the most active androgen in the prostate. Prostate cancer is one of the most common cancers among men and androgens are involved in controlling the growth of androgen-sensitive malignant prostatic cells. The endocrine therapy used to treat prostate cancer aims to eliminate androgenic activity from the prostatic tissue. Most prostate cancers are initially responsive to androgen withdrawal but become later refractory to the therapy and begin to grow androgen-independently. Using LNCaP prostate cancer cell line we have developed a cell model to study the progression of prostate cancer. In the model androgen-sensitive LNCaP cells are transformed in culture conditions into more aggressive, androgen-independent cells. The model was used to study androgen and estrogen metabolism during the transformation process. Our results indicate that substantial changes in androgen and estrogen metabolism occur in the cells during the process. A remarkable decrease in the oxidative 17beta-hydroxysteroid dehydrogenase activity was seen whereas the reductive activity seemed to increase. The changes suggest that during transformation estrogen influence is increasing in the cells. This is supported by the cDNA microarray screening results which showed over-expression of several genes up-regulated by estrogens in the LNCaP cells line representing progressive prostate cancer. Since local steroid metabolism controls the bioavailability of active steroid hormones in the prostate, the variations in steroid-metabolizing enzymes during cancer progression may be crucial in the regulation of the growth and function of the organ.

Intracellular machinery for matrix degradation in bone-resorbing osteoclasts

In osteoclasts, TRACP co-localized with cathepsin K in transcytotic vesicles and was activated by cathepsin K in vitro, suggesting that TRACP may degrade organic matrix components in transcytotic vesicles in an event regulated by cathepsin K.

INTRODUCTION

TRACP is an enzyme with unknown biological function. In addition to its phosphatase activity, TRACP is capable of generating reactive oxygen species (ROS). Bone-resorbing osteoclasts contain large amounts of TRACP, and transgenic animal models suggest that TRACP has a role in bone resorption. Osteoclasts resorb bone by secreting acid and lysosomal enzymes such as cathepsin K into an extracellular resorption lacuna between the cell membrane and bone surface. Matrix degradation products are then endocytosed, transcytosed, and secreted through a functional secretory domain in the basolateral membrane facing bone marrow.

MATERIALS AND METHODS

We have studied intracellular localization of TRACP in osteoclasts with antibodies against various known endosomal and lysosomal proteins using confocal microscopy. We also studied co-localization of TRACP with cathepsin K and endocytosed bone matrix components and the effect of cathepsin K digestion on the ROS generating activity of TRACP in vitro.

RESULTS

Double-staining experiments of TRACP with endosomal and lysosomal markers showed that, although some endosomal staining was detected, TRACP was not present in lysosomes. However, TRACP was present in transcytotic vesicles, where it co-localized with cathepsin K. Cathepsin K digestion of TRACP in vitro increased the phosphatase activity by 5.6-fold and the ROS generating activity by 2.0-fold.

CONCLUSIONS

These results suggest that cathepsin K may activate the ROS-generating activity of TRACP in transcytotic vesicles of resorbing osteoclasts, the ROS being targeted to finalize degradation of organic bone matrix components during their transcytosis.

Tartrate-resistant acid phosphatase 5B circulates in human serum in complex with alpha2-macroglobulin and calcium

Tartrate-resistant acid phosphatase (TRACP) is an enzyme with unknown biological function. In addition to its acid phosphatase activity, TRACP is capable of generating reactive oxygen species (ROS) at neutral pH. Two forms of TRACP circulate in human serum, macrophage-derived TRACP 5a and osteoclast-derived TRACP 5b. Here we have studied the circulating forms of the osteoclast-derived TRACP 5b in rat and human serum. In human serum, TRACP 5b circulates in a large complex that contained alpha2M and calcium. On the contrary, rat serum TRACP 5b circulates as a free molecule. Formation of the TRACP 5b complex in vitro decreased significantly the ROS generating activity of TRACP 5b without affecting its phosphatase activity. These results suggest that the complex formation may be necessary to eliminate the formation of the harmful ROS in the neutral pH of serum.

A novel immunoassay for the determination of tartrate-resistant acid phosphatase 5b from rat serum

Osteoclasts secrete tartrate-resistant acid phosphatase 5b (TRACP 5b) into the circulation. We have developed an immunoassay for the determination of rat TRACP 5b activity. Intra-assay variation of the immunoassay was 4.5%, interassay variation was 3.8%, dilution linearity was 104.6 +/- 7.6%, and recovery of recombinant rat TRACP was 99.1 +/- 5.8%. We studied serum TRACP 5b as a marker of bone resorption using orchidectomized (ORC) rats as a model for osteoporosis and age-matched sham-operated rats as controls in a 6-month study. After the operation, trabecular bone mineral density decreased significantly more in the ORC group than in the sham group, whereas cortical bone mineral density increased similarly in both groups. Serum TRACP 5b activity was significantly elevated within the first week after ORC, returned to the control level in the third week, and was not increased above the sham level at any of the later time points. At 6 months, trabecular bone volume was 80% lower in ORC rats than in controls. Osteoclast number per trabecular bone perimeter was slightly increased, but the absolute number of osteoclasts in trabecular bone was significantly decreased. These results suggest that absolute bone resorption is increased within the first week after ORC. Later, it is decreased because there is less bone to be resorbed. However, relative bone resorption (compared with the amount of remaining bone) is still increased, leading to further bone loss. We conclude that serum TRACP 5b is a useful marker for monitoring changes in the bone resorption rate in rat ORC model.

Phosphatase and oxygen radical-generating activities of mammalian purple acid phosphatase are functionally independent

Bone-resorbing osteoclasts and activated macrophages express large amounts of tartrate-resistant acid phosphatase (TRAP), an iron-containing enzyme with unknown biological function. We studied acid phosphatase (AcP) and reactive oxygen species (ROS)-generating activities of recombinant rat TRAP. pH optimum was 4.5 for AcP activity and 6.5 for ROS-generating activity. Replacement of His113 and His216 by site-directed mutagenesis severely inhibited AcP activity, but had no significant effects on ROS-generating activity. Substrate specificity was not affected by the mutations. These results suggest that AcP and ROS-generating activities of TRAP are functionally independent.

Intracellular fragmentation of bone resorption products by reactive oxygen species generated by osteoclastic tartrate-resistant acid phosphatase

Tartrate-resistant acid phosphatase (TRAP) is highly expressed in bone-resorbing osteoclasts and activated macrophages. It has been suggested that a redox-active iron in the binuclear iron center of TRAP could have the capacity to react with hydrogen peroxide to produce highly destructive reactive oxygen species (ROS). Here we show that TRAP can generate ROS in vitro and that cells over-expressing TRAP produce higher amounts of intracellular ROS than their parent cells. We further demonstrate that these ROS can be targeted to destroy collagen and other proteins. In resorbing osteoclasts, TRAP was found in transcytotic vesicles transporting matrix degradation products through the cell, suggesting that TRAP-facilitated fragmentation of endocytosed material takes place in a specific cellular compartment. These results suggest that bone matrix degradation occurs not only extracellularly in the resorption lacunae but also intracellularly in the transcytotic vesicles. We propose that proteins containing redox-active iron could represent a novel mechanism of physiological fragmentation of organic molecules. This mechanism could be important in tissue remodeling and as a defense mechanism of phagocytosing cells.

Three-dimensional structure of a mammalian purple acid phosphatase at 2.2 A resolution with a mu-(hydr)oxo bridged di-iron center

The crystal structure of purple acid phosphatase from rat bone has been determined by molecular replacement and the structure has been refined to 2.2 A resolution to an R -factor of 21.3 % (R -free 26.5 %). The core of the enzyme consists of two seven-stranded mixed beta-sheets, with each sheet flanked by solvent-exposed alpha-helices on one side. The two sheets pack towards each other forming a beta-sandwich. The di-iron center, located at the bottom of the active-site pocket at one edge of the beta-sandwich, contains a mu-hydroxo or mu-oxo bridge and both metal ions are observed in an almost perfect octahedral coordination geometry. The electron density map indicates that a mu-(hydr)oxo bridge is found in the metal center and that at least one solvent molecule is located in the first coordination sphere of one of the metal ions. The crystallographic study of rat purple acid phosphatase reveals that the mammalian enzymes are very similar in overall structure to the plant enzymes in spite of only 18 % overall sequence identity. In particular, coordination and geometry of the iron cluster is preserved in both enzymes and comparison of the active-sites suggests a common mechanism for the mammalian and plant enzymes. However, significant differences are found in the architecture of the substrate binding pocket.

Tartrate-resistant bone acid phosphatase: large-scale production and purification of the recombinant enzyme, characterization, and crystallization

Tartrate-resistant acid phosphatase (TRAP) is an enzyme expressed in bone-resorbing osteoclasts and certain tissue macrophages in human tissues. The functions of TRAP in biological systems are not known. Elucidation of the three-dimensional structure of the active site could yield important information about the physiological substrate(s) of the enzyme. We have produced recombinant rat bone TRAP using a baculovirus expression vector system. The production was scaled up to a 30-l bioreactor, and a method of purification in large scale was developed. The enzyme is composed of one 34 kDa polypeptide chain. Trypsin digestion resulted in a preparation where two subunits of approximately 23 kDa and approximately 16 kDa appeared after disulfide reduction. Trypsin digestion activated the enzyme. We generated monoclonal antibodies against recombinant TRAP. One of the selected antibodies detected the 23 kDa subunit in Western blotting. The reduced and oxidized forms of the enzyme could be separated by Mono-S cation-exchange chromatography. Crystals of TRAP have been obtained with ammonium sulfate/polyethylene glycol as precipitant. They belong to space group P212121 or P21212 with unit cell dimensions a = 57.2 A, b = 69.5 A, and c = 87.2 A and diffract to at least 2.2 A resolution. A packing density value of 2.55 A3/Da is consistent with one subunit in the asymmetric unit.

Studies on the protein tyrosine phosphatase activity of tartrate-resistant acid phosphatase

Tartrate-resistant acid phosphatase (TRAP) is an enzyme with unknown biological function. In human tissues, its expression is restricted to bone-resorbing osteoclasts and activated macrophages. Osteoclasts secrete TRAP to the circulation during bone resorption. Reduction of the enzyme's binuclear iron center is important in regulating its activity. The purple form of the enzyme is inactive and contains two ferric ions. Mild reduction activates it to a pink form containing one ferric and one ferrous ion. Instead, strong reduction removes the iron content, resulting in a colorless, inactive enzyme. We describe spontaneous activation of the purple form to the pink form upon incubation at +37 degrees C. Further incubation results in slow inactivation of the enzyme and color change to yellowish. The enzyme purified from osteoclasts is a mixture of the purple and pink forms, but the enzyme purified from serum represents the yellowish form. We suggest that the newly synthesized enzyme is purple and reduced in the cell to the functionally active pink form. After fulfilling its biological function in the cell, the enzyme is further reduced to the yellowish form and secreted into the circulation. In the serum, further reduction would dissociate the iron content. The enzymes from osteoclasts and macrophages had similar catalytic properties, both being active as a protein tyrosine phosphatase (PTPase). The acid phosphatase (AcP) and PTPase activities were similar, and the preferred AcP substrate, pNPP, was processed in the same active site as phosphotyrosine. Our results suggest that redox-regulated PTPase activity may be a major function of TRAP in vivo.

Consistency of patient- and doctor-assessed cosmetic outcome after conservative treatment of breast cancer

The cosmetic results of the breast (144 patients) were analysed after segmental resection and axillary dissection with or without postoperative radiotherapy for early low-risk breast cancers. Cosmetic results were assessed over time (3, 9, 18, 36, 48 months respectively) by the patient and by the physician. Patients rated the overall cosmetic result good or excellent in 92% of cases after 3 months. The proportion of good or excellent cosmetic results decreased over time and after four years 89% of patients classified themselves in this category, whereas the physician assessed the outcome as good or excellent in 91% of cases after 3 months and 75% after 4 years. The inter-observer consistency between physician and patient in assessing the cosmetic outcome was kappa = 0.42 at the beginning and decreased over time (kappa = 0.07 after 4 years). The intra-observer variation over time was kappa = 0.53 for the patient and kappa = 0.32 for the physician. Inter-observer consistency between patient and physician was moderate immediately following treatment but decreased over time. The feeling of satisfaction of the patient was relatively stable whereas the opinion of the physician became somewhat more critical over time. Therefore the intra-observer consistency over time was somewhat better for the patient than for the physician.

Use of hospital services by breast cancer patients by stage of the disease: implications on the costs of cancer control

The use of resources for breast cancer during the first five years after diagnosis by different stages of disease was evaluated on the basis of all breast cancer patients (555) diagnosed in the Tampere University hospital district (Finland). All outpatient visits or inpatient-days of these patients in any hospital of the district were recorded and the average costs of hospital-day and of outpatient visit were applied to quantify the total use of resources. During the first five years of follow-up 535 breast cancer patients had 8206 follow-up visits and spent 18472 days in hospital. The stage II-IV patients had more than twice as many outpatient visits and inpatient-days as the stage I patients. The number of hospital-days/patient-year was 2.4-fold for stage II patients and 4.1-fold for stage III-IV patients as compared to stage I patients. The overall use of resources/patient for those with nonlocalized disease was twice as high as the use for stage I patients, while the use of resources/person-year was 2.3-fold for stage II patients and 3.6-fold for stage III-IV as compared to stage I patients. Our study in an unselected patient population during the first five years of follow-up shows that breast cancer patients diagnosed in the early stage (stage I) require far fewer health care resources than if diagnosed in advanced stages. The results can be directly transformed into costs of breast cancer control by stage of breast cancer.

Tangential breast irradiation with or without internal mammary chain irradiation: results of a randomized trial

A prospective randomized study was made of 270 patients with unilateral stage I or II invasive breast cancer treated by segmental resection, axillary dissection and radiation at the University Hospital of Tampere, Finland, between 1989 and 1991. The aim of the study was to determine whether there is any advantage or disadvantage if the internal mammary chains (IMC) are included in the radiation target volume. The medial and lateral two-field technique was used and the target volumes were determined randomly either to include the internal mammary chain (IMC-RT) or not (no-IMC-RT). The prevalence of radiation pneumonitis was 16% and there was no significant difference between the IMC- and no-IMC-groups (18 vs. 14%). Skin reactions were equal in both groups. Lung fibrosis was more common in the IMC-RT group.

IN CONCLUSION

radiation of internal mammary chain after conservative surgery does not lead to an increase in clinically important skin or pulmonary complications. Whether it prevents recurrences or new primaries of the opposite breast is too early to say because of the short follow-up time.

Autophagic vacuoles fuse with the prelysosomal compartment in cultured rat fibroblasts

We previously demonstrated both mannose 6-phosphate receptor (MPR) and cathepsin L in early autophagic vacuoles of cultured rat fibroblasts. This suggested that the enzyme may originate either from the receptor-enriched prelysosomal compartment (PLC) or from the trans-Golgi network (TGN). In the present ultrastructural study, we elucidated the roles of the PLC and TGN in lysosomal enzyme delivery to autophagic vacuoles. Firstly, we studied whether endocytic markers, cationized ferritin (CF), bovine serum albumin-gold or horseradish peroxidase (HRP), can be detected in autophagic vacuoles. Autophagy was induced by serum removal from the medium with or without leupeptin, an inhibitor of cysteine proteinases. Endocytic markers were not detected in autophagic vacuoles after short uptake which filled the early endosome, but only after longer labeling which filled the PLC. The markers were usually found in advanced autophagic vacuoles containing partially degraded cytoplasm and complex internal membranes which are the characteristic of the PLC. HRP-positive vesicles were also observed in continuity with early autophagic vacuoles containing intact cytoplasm. After uptake and transport of CF and HRP to the PLC, these markers were delivered to autophagic vacuoles even if microtubules were disrupted in vinblastine before the induction of autophagy. Secondly, we studied whether MPRs transport cathepsin L to autophagic vacuoles directly from the TGN. Two inhibitors of MPR-mediated enzyme transport, tunicamycin and chloroquine, were used. Quantitative immunocytochemistry showed that neither of these drugs prevented cathepsin L delivery to autophagic vacuoles. The results suggest that a large proportion of lysosomal enzymes is delivered to autophagic vacuoles from the PLC by a microtubule-independent manner. The first enzymes may be transported in small PLC-derived vesicles or tubules which are reached by HRP but not by CF and gold. Later, the autophaged cytoplasm is delivered to larger vacuolar parts of the PLC. Mannose 6-phosphate receptors transport no or only trace amounts of lysosomal enzymes to autophagic vacuoles directly from the TGN.