Device for filamentous fungi growth monitoring using the multimodal frequency response of cantilevers.

Filamentous fungi cause opportunistic infections in hospital patients. A fast assay to detect viable spores is of great interest. We present a device that is capable of monitoring fungi growth in real time via the dynamic operation of cantilevers in an array. The ability to detect minute frequency shifts for higher order flexural resonance modes is demonstrated using hydrogel functionalised cantilevers. The use of higher order resonance modes sees the sensor dependent mass responsivity enhanced by a factor of 13 in comparison to measurements utilizing the fundamental resonance mode only. As a proof of principle measurement, Aspergillus niger growth is monitored using the first two flexural resonance modes. The detection of single spore growth within 10 h is reported for the first time. The ability to detect and monitor the growth of single spores, within a small time frame, is advantageous in both clinical and industrial settings.

Prevalence of postweaning multisystemic wasting syndrome in pigs sired by 13 Hungarian Landrace boars.

Between February 20 and October 31, 2003, 2034 sows were inseminated with semen collected from 13 Hungarian Landrace boars. Altogether 16,013 piglets were born: 13,801 (86.2 per cent) alive, 796 (4.97 per cent) stillborn and 156 (0.97 per cent) mummified. A total of 1260 (7.87 per cent) of the pigs developed signs of postweaning multisystemic wasting syndrome (PMWS). In the groups of sows inseminated with semen from each of the 13 boars, the percentages of farrowings producing piglets with signs of PMWS, stillborn piglets or mummified piglets were very high (59.4 per cent, 57.6 per cent and 13.8 per cent, respectively). There were significant differences between the proportions of piglets with signs of PMWS, stillborn piglets and mummified piglets sired by the different boars: 3.06 to 15.6 per cent, 1.76 to 8.52 per cent and 0 to 3.22 per cent, respectively.

A new mutation in Muir-Torre syndrome associated with familiar transmission of different gastrointestinal adenocarcinomas.

Hereditary Nonpolyposis Colorectal Carcinoma (HNPCC) is the most frequent inherited disease which can lead to the development of tumors in the colon and other locations. Its genetic basis is related to the germline mutation of the Mismatch Repair (MMR) genes. Muir-Torre syndrome is considered one of the subtypes of this disease, in which the HNPCC tumor spectrum is frequently associated with sebaceous carcinoma of the skin or keratoacanthoma. A 57 years old male patient is presented with a mucinous carcinoma of the caecum and an adenocarcinoma of the pancreas head. A malignant sebaceous carcinoma was removed from his left neck area. His family history was significant for two cases of colon carcinoma, two cases of stomach cancer and a case of metacron endometrial and skin tumor as well. Both the colon carcinoma and the skin tumor proved to be microsatellite unstable. An Arg>Pro switch missense mutation was found in codon 265 of the hMLH1 gene. This error was found in 4 other members of his family. The detected genetic alteration was considered pathogenic and was not published yet in English literature. The significance of this particular case is the rare tumor association in a patient with Muir-Torre syndrome (MTS). In cases of sebaceous skin lesions, evaluation of family history is of utmost importance in the early detection of HNPCC and in the follow up care of family members with the particular mutation.

Renal artery aneurysm at the anastomosis after kidney transplantation.

Vascular complications represent serious problems after kidney transplantation. An aneurysm of the transplanted renal artery is an extremely rare but potentially devastating complication that which occurs in fewer than 1% of recipients. It can cause hypertension, functional impairment, and even graft loss. A 49-year-old man was admitted 6 months after his second renal transplantation. Duplex ultrasonography demonstrated an aneurysm at the anastomosis of the transplanted renal artery. The patient has not had any complaints. The function of the graft was stable. A computed tomography scan confirmed the diagnosis. Because of the high risk of rupture we decided upon surgical repair. During the operation, blood flow to the kidney was occluded; the graft was cooled with Euro-Collin's solution and ice-cold saline. After the resection there was enough usable arterial wall to construct a new anastomosis. The patient had an uneventful postoperative period, the serum creatinine decreased to the preoperative level, and the function of the graft was stable. Renal artery aneurysms represent high-risk complications. We decided on surgical repair, which was performed with simultaneous perfusion and cooling of the graft. There are only a few similar cases in the literature; it was the first operation using this method in our practice. Surgical reconstruction of a renal artery aneurysm, if feasible, is a safe procedure that prevents aneurysm rupture and saves the graft.

Establishment of the hu-PBL-SCID mouse model for the investigation of thyroid cancer.

New experimental models of human neoplastic diseases attempt to mimic the human environment that fostered the development of disease in cancer patients. The aim of the present study was to establish a human lymphocyte-engrafted, severe combined immunodeficient (hu-PBL-SCID) mouse model to investigate thyroid cancer and to evaluate the potential use of this model for cancer immunotherapy. Thyroid neoplastic tissues were obtained from ten patients (one follicular adenoma, five papillary, one follicular, one anaplastic and two medullary cancers). One 8 x 4 x 3 millimeter sample from each tumor was cut into two pieces of identical size and transplanted into two SCID mice. In each case, one of the two mice was injected intraperitoneally with lymphocytes from the same tumor patient for the reconstitution of the human immune system (Group A), while the other animal received no lymphocytes (Group B). The engraftment of the tumors was successful in all cases. The growth rate was highly dependent on the histological type. When histologies were compared before implantation and after the removal of the implants, the characters of the tumors proved to be unchanged, except one case where an anaplastic cancer arose from a papillary tumor. Macrophages were present in all but one papillary cancer. All differentiated thyroid cancers were infiltrated by T and B lymphocytes. Lymphocytes and macrophages disappeared from 19/20 grafts by week 16. However, in one case from group A lymphocytes were detected four months after the transplantation. In another case from group A, one papillary cancer spontaneously decreased in size and disappeared. Before implantation, HLA-DR expression was detected in every papillary cancer. HLA-DR expression in the grafts was not seen in 3/5 cases by week 16. In conclusion, an animal model has been established for the investigation of human thyroid cancer, by which the analysis of anti-tumor immunity, as a postulate of immune therapy, may be possible.

Differentiated thyroid cancer and outcome in iodine deficiency.

AIMS: Factors influencing prognosis and long-term outcome of thyroid cancer have been described by several groups. We wished to asses the previously described prognostic factors in a moderately iodine deficient region in Hungary. METHODS: Four hundred and fifty-four out of 492 patients who had surgery for papillary thyroid cancer (PTC, 386 cases) and follicular thyroid cancer (FTC, 106 cases) between 1971 and 1998 were analyzed. Survival curves were compared using the Kaplan-Meier method and Cox regression analysis. RESULTS: The 10 and 20-year survival rates were 87.9 and 84% for PTC, and 78.2 and 78.2% for FTC. In PTC, extrathyroidal invasion (p<0.0001), lymph node metastasis (p<0.0001), distant metastasis (p<0.0001), and age over 40 years (p=0.002) were significant adverse predictors. In FTC, extrathyroidal invasion (p=0.003) distant metastases (p<0.0001), and age over 40 years (p=0.011) were significant adverse predictors. CONCLUSION: Iodine intake did not appear to influence survival. The incidence of follicular cancer, which has less favourable prognosis, was higher in iodine deficient regions. This supports the importance of iodine supplementation in these areas.

Comparison of calcium and alfacalcidol supplement in the prevention of osteopenia after kidney transplantation.

The aim of this observational study was to compare the effect of calcium and alfacalcidol supplementation on the regression of hyperparathyroidism and on prevention of osteopenia in patients up to 3 years after renal transplantation. Two historical cohorts were compared for that purpose. One hundred and fifty-nine patients received calcium carbonate supplement (group 1), while 81 patients were treated with alfacalcidol (group 2). Serum Ca, phosphate (P), Mg, creatinine, alkaline phosphatase (AP) and parathyroid hormone (PTH) levels were determined before and after transplantation in the two groups, for 3 years. Femoral neck and lumbar spine bone mineral density (BMD) was measured only at 3 and 6 months and 1, 2 and 3 years after transplantation. At baseline there was no difference in age or sex ratio, but prevalence in post-menopausal women was higher in group 1 (6.9% versus 1.2%). Duration on dialysis was comparable but prevalence of interstitial and undetermined nephropathies was higher in group 1. Baseline serum concentrations of PTH, Ca and P were comparable in both groups. After transplantation, plasma creatinine decreased to comparable levels in both groups. Immunosuppression by triple therapy was more prevalent in group 2, so that cumulative dose of steroid was higher in group 1, especially at 1 month because of higher incidence of acute rejections (51% versus 13%). Mean intact PTH levels decreased in both groups, from 18 pmol/l to 8.4 and 7.9 at 3 years, but the decrease was significantly greater with alfacalcidol at 6 and 12 months. At 3 months, BMD were comparable at both sites. From 3 months to 3 years after kidney transplantation, mean lumbar spine BMD significantly increased from 0.963 to 1.054 g/cm(2) in group 1, whereas there was no significant decrease (1.048 to 1.006 g/cm(2)) in group 2, the difference in changes being significant ( P<0.05). Femoral neck BMD was not significantly increased in either group (0.932 to 0.993 g/cm(2) in group 1, and 0.850 to 0.907 g/cm(2) in group 2). Expressed as percentages, these changes were +9.4% and -4% for lumbar BMD and +6.5% and +6.7% for femoral neck, for groups 1 and 2, respectively. Prevalence of osteopenia was not significantly lower at 3 years in group 1 (45% and 51%) than in group 2. During the follow-up period, osteonecrosis was diagnosed in six patients (3.8%) in group 1 and in nine (11%) in group 2. In conclusion, alfacalcidol compared to CaCO3 supplement suppressed hyperparathyroidism more rapidly and strongly. In spite of higher osteopenia risk in the CaCO3 group, lumbar BMD increase was greater and incidence of osteonecrosis higher in this group, suggesting better bone protection with CaCO3 than with alfacalcidol.

Flow cytometric DNA analysis of benign hyperfunctioning parathyroid glands: significant difference in the S phase fraction and proliferative index between adenomas and hyperplasias.

AIMS: Flow cytometric DNA analysis was performed to measure the DNA content of benign parathyroid tumours in patients with primary hyperparathyroidism. METHODS: DNA analysis of paraffin-embedded parathyroid samples was performed on 51 parathyroid glands from 29 patients after parathyroidectomy. Histopathology showed parathyroid adenoma in 25 cases and hyperplasia in four patients. DNA ploidy status, DNA index (DI), percentage of cells in S phase and proliferative index (PI) were determined. RESULTS: Normal cells from normal glands were all diploid. DNA cytometry showed 12 aneuploid and 13 diploid adenomas. There were 12 diploid and four aneuploid hyperplastic glands. Incidence of aneuploid DNA histograms did not show a statistically significant difference between adenomas and hyperplasias (P=0.216). Mean S phase fraction was 3.45% in adenomas and 1.53% in hyperplasias (P= 0.015). Mean PI was 6.48% in adenomas and 2.78% in hyperplastic parathyroid glands. This difference was statistically significant (P=0.006). Diploid cases had a mean PI of 4.78% and aneuploid glands a mean PI of 7.7% (P=0.08). Aneuploid DNA content did not reveal statistically significant correlation with age, gender, pre-operative Ca, alkaline phosphatase, i-PTH levels, and tumour size. The mean S phase fraction and PI were 2.25% and 4.78% in diploid glands, and 4.5% and 7.7% in aneuploid cases. CONCLUSION: Aneuploid DNA content may be present in benign parathyroid diseases, but not in normal parathyroid glands. Aneuploid DNA histograms and higher PI occur more often in adenomas compared with hyperplasias, but the nuclear DNA analysis is unable to make a distinction between adenomas and hyperplasias.

Technetium-99m-sestamibi/pertechnetate subtraction scintigraphy vs ultrasonography for preoperative localization in primary hyperparathyroidism.

A prospective study was performed to evaluate the efficacy of technetium-99m-sestamibi and technetium-99m-pertechnetate subtraction scanning and US for imaging parathyroid glands in primary hyperparathyroidism. Sixty-three patients were surgically treated for primary hyperparathyroidism (HPT). Preoperative scintigraphy and US were performed in all cases. Bilateral neck exploration was carried out on each patient. Results of radionuclide studies and US were compared with surgical and histological findings. In 57 patients with primary HPT the radionuclide scanning gave true-positive results. Four false-negative and two false-positive scintigrams were obtained. The sensitivity and the positive predictive value (PPV) of scintigraphy were 93 and 97%, respectively. Forty-one cases were correctly localized by the US. Seventeen US results were false negative and five were false positive. The sensitivity and the PPV for US were 71 and 89%, respectively. There was a statistically significant difference between the sensitivity of the scintigraphy compared with the US ( p=0.001). Sensitivities of radionuclide scans and US were higher for adenomas (100 and 83%) than for hyperplastic glands (75 and 40%). The sensitivity of technetium-99m-sestamibi and technetium-99m-pertechnetate subtraction scintigraphy was significantly higher compared with US. This sensitive method could help surgeons in performing a rapid and directed parathyroidectomy.

COOH-terminal truncations promote proteasome-dependent degradation of mature cystic fibrosis transmembrane conductance regulator from post-Golgi compartments.

Impaired biosynthetic processing of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR), a cAMP-regulated chloride channel, constitutes the most common cause of CF. Recently, we have identified a distinct category of mutation, caused by premature stop codons and frameshift mutations, which manifests in diminished expression of COOH-terminally truncated CFTR at the cell surface. Although the biosynthetic processing and plasma membrane targeting of truncated CFTRs are preserved, the turnover of the complex-glycosylated mutant is sixfold faster than its wild-type (wt) counterpart. Destabilization of the truncated CFTR coincides with its enhanced susceptibility to proteasome-dependent degradation from post-Golgi compartments globally, and the plasma membrane specifically, determined by pulse-chase analysis in conjunction with cell surface biotinylation. Proteolytic cleavage of the full-length complex-glycosylated wt and degradation intermediates derived from both T70 and wt CFTR requires endolysosomal proteases. The enhanced protease sensitivity in vitro and the decreased thermostability of the complex-glycosylated T70 CFTR in vivo suggest that structural destabilization may account for the increased proteasome susceptibility and the short residence time at the cell surface. These in turn are responsible, at least in part, for the phenotypic manifestation of CF. We propose that the proteasome-ubiquitin pathway may be involved in the peripheral quality control of other, partially unfolded membrane proteins as well.

[The role of MIBI scintigraphy in the early detection of breast cancer]. / A MIBI szcintigráfia szerepe az emlórákok korai diagnosztikájában.

The authors investigate the role of MIBI scintigraphy in the early diagnosis of breast cancer. The importance of early diagnosis is emphasized by the fact that breast cancer has the highest morbidity and mortality preceding cervical carcinoma amongst women. Retrospective examinations were made in case of 42 patients operated before because of breast cancer in order to examine accuracy of both mammography and scintigraphy in comparison with the results of histological diagnosis. In these cases sensitivity of scintigraphy turned out to be 69%, while its specificity 42%. In cases of mammographical investigations the sensitivity proved to be 74% and specificity was 61%. Besides mammography, scintigraphy has a very important additional role in the diagnosis of breast cancer. Because of its results and costs scintigraphy is not able to take over the mammography's dominant position (as a popular diagnostic method) but in selected patients' groups it can help to realise tumors as well as to avoid unnecessary operations or needle biopsis. Based on our results this method can give significant additional information in T1b and especially in T1c states of tumors. Therefore this method can be offered as an additional investigation in cases of physically realised or mammographically screened, but not-palpable, larger than 1 cm size lumps when there is little or moderate risk of malignancy.

[Differentiated thyroid carcinoma: prognostic factors]. / Differenciált pajzsmirigy carcinoma: prognosztikai faktorok vizsgálata.

Factors influencing prognosis and long term outcome of thyroid cancer have been described by several groups. It is, however, not clear how the moderate iodine deficiency in Hungary can influence the previously described prognostic factors by other means than shifting differentiated cancer incidence toward the follicular type. Data of 423 out of 472 patients who had been operated on for papillary (372) and follicular (100) thyroid cancer between 1971 and 1997 at our institution have been analyzed retrospectively. Histological specimens were re-evaluated and, if needed, revised. Survival curves were compared using the Kaplan-Meier method. The overall 5 and 10 year survival rates were 93% and 89% for papillary, and 92% and 80% for follicular carcinoma. As an independent factor extrathyroidal invasion (papillary p = 0.000, follicular p = 0.000), lymph node involvement (papillary p = 0.000, follicular 0.011), distant metastases (papillary p = 0.000, follicular p = 0.000), and age over 40 years (papillary p = 0.000, follicular p = 0.000) had negative influence on survival. Multifocality, gender, type of surgery (total or near-total thyroidectomy vs. less than near-total thyroidectomy), and lymphocytic infiltration did not influence survival. Iodine intake did not influence survival, however, the incidence of follicular cancer was higher in iodine deficient regions. When analyzing the papillary and follicular groups separately by Cox regression, extrathyroidal invasion (p = 0.008), lymph node metastasis (p = 0.004), distant metastasis (p = 0.000), and age over 40 years (p = 0.000) were significant predictors in the papillary group, while only tumor extrathyroidal invasion (p = 0.019), and distant metastases (p = 0.000) were significant negative factors in the follicular group.

Multiple endocytic signals in the C-terminal tail of the cystic fibrosis transmembrane conductance regulator.

The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-dependent protein kinase (PKA)-activated chloride channel that is localized to the plasma membrane and endosomal compartment. Endosomal targeting of CFTR is attributed to the Tyr(1424)-based internalization signal, identified in the C-terminal tail of the channel. Mutation of the Tyr(1424) residue could partly inhibit the endocytosis of CFTR and its association with the adapter protein AP-2. To reveal additional endosomal targeting signals, site-directed mutagenesis of both a chimaera, composed of a truncated form of interleukin 2 receptor alpha chain (TacT) and the C-terminal tail of CFTR (Ct), and the full-length CFTR was performed. Morphological and functional assays revealed the presence of multiple internalization motifs at the C-terminus, consisting of a phenylalanine-based motif (Phe(1413)) and a bipartite endocytic signal, comprising a tyrosine (Tyr(1424)) and a di-Leu-based (Leu(1430)-Leu) motif. Whereas the replacement of any one of the three internalization motifs with alanine prevented the endocytosis of the TacT-Ct chimaera, mutagenesis of Phe(1413)-Leu impaired the biosynthetic processing of CFTR, indicating that Phe(1413) is indispensable for the native structure of CFTR. In contrast, replacement of Leu(1430)-Leu- and Tyr(1424)-based signals with alanine increased the cell-surface density of both the chimaeras and CFTR in an additive manner. These results suggest that the internalization of CFTR is regulated by multiple endocytic sorting signals.

Conformational and temperature-sensitive stability defects of the delta F508 cystic fibrosis transmembrane conductance regulator in post-endoplasmic reticulum compartments.

Deletion of phenylalanine at position 508 (DeltaF508) is the most common cystic fibrosis (CF)-associated mutation in the CF transmembrane conductance regulator (CFTR), a cAMP-regulated chloride channel. The consensus notion is that DeltaF508 imposes a temperature-sensitive folding defect and targets newly synthesized CFTR for degradation at endoplasmic reticulum (ER). A limited amount of CFTR activity, however, appears at the cell surface in the epithelia of homozygous DeltaF508 CFTR mice and patients, suggesting that the ER retention is not absolute in native tissues. To further elucidate the reasons behind the inability of DeltaF508 CFTR to accumulate at the plasma membrane, its stability was determined subsequent to escape from the ER, induced by reduced temperature and glycerol. Biochemical and functional measurements show that rescued DeltaF508 CFTR has a temperature-sensitive stability defect in post-ER compartments, including the cell surface. The more than 4-20-fold accelerated degradation rate between 37 and 40 degrees C is, most likely, due to decreased conformational stability of the rescued DeltaF508 CFTR, demonstrated by in situ protease susceptibility and SDS-resistant thermoaggregation assays. We propose that the decreased stability of the spontaneously or pharmacologically rescued mutant may contribute to its inability to accumulate at the cell surface. Thus, therapeutic efforts to correct the folding defect should be combined with stabilization of the native DeltaF508 CFTR.

[Fifteen years experience in the surgical treatment of primary hyperparathyroidism]. / Tizenöt év alatt szerzett tapasztalataink a primer hyperparathyreosis sebészi kezelésében.

We measured the efficacy of preoperative localization techniques and results of parathyroidectomy in patients with primary hyperparathyroidism (HPT). From 1986 to 2001, 92 patients were treated with primary HPT. Preoperative localization technique was used in all patients (US n = 85, Tc-99m-sestamibi/Tc-99m-pertechnetate subtraction scintigraphy n = 67, CT n = 18, MRI n = 14) to visualize the abnormal parathyroids. Results of localization studies were compared with surgical and pathological findings. Bilateral neck exploration was carried out in each patient for the identification of all parathyroid glands. If parathyroid adenoma was diagnosed, exstirpation of the abnormal parathyroid was performed. If diffuse hyperplasia was diagnosed, subtotal parathyroidectomy (3 1/2) was performed. The overall sensitivity was 94% for scintigraphy, 74% for US, 67% for CT and 50% for MRI. The PPV was 97% for scintigraphy, 92% for US, 100% for CT and for MRI. At surgery 66 patients had single adenomas and 3 patients had double adenomas. Diffuse hyperplasia was diagnosed in 21 and parathyroid carcinoma was found in 2 patients. Persistent HPT was noted in 1 patient. Recurrent HTP occurred 4 times. After a second operation their HPT disappeared. In conclusion, the sensitivity of Technetium-99m-sestambi and Technetium-99m-pertechnetate subtraction scanning was significantly superior compared to other localization methods. The use of these sensitive preoperative technique can improve the success rate, and decrease the incidence of persistent and recurrent HPT.

[Results and complications of parathyroidectomy in secondary hyperparathyroidism]. / Szekunder hyperparathyreosis miatt végzett parathyroidectomiák eredményessége és szövódményei.

Retrospective study was performed to measure the results of parathyroidectomy in patients with secondary hyperparathyroidism. From 1987 to 2000, 48 patients underwent surgery for secondary hyperparathyroidism. There were 30 of 48 patients on haemodialysis treatment, and 11 patients were in pre-dialysis stage. Parathyroidectomy was performed after successful kidney transplantation in 4 cases. Indication of the surgery was extremely elevated serum level of parathyroid hormone (at least 10 fold elevation), which was resistant for the conservative medical therapy. Subtotal parathyroidectomy (3 1/2) was performed in 30 patients. Five patients underwent total parathyroidectomy and autotransplantation. Only 2 or 3 parathyroid glands have been removed in 13 patients. Haematoma occurred in 3 cases after parathyroidectomy. Recurrent nerve injury or septic complication did not occur. Two patients died in the early postoperative period due to cardiac failure. Tetania was noted in 2 patients after surgery. Permanent postoperative hypocalcaemia (over 6 months) occurred in 3 cases. Persistent hyperparathyroidism was diagnosed in 5 patients. In these patients 2 parathyroid glands were removed during the primary operation. Recurrent hyperparathyroidism was detected in 2 patients. Subtotal parathyroidectomy was carried out in these cases previously. At the reoperation for persistent and recurrent hyperparathyroidism, total parathyroidectomy and autotransplantation was performed. Serum alkaline phosphatase level and serum parathyroid hormone value decreased after surgery, except those patients with persistent hyperparathyroidism. Bone pain decreased in 96% of the cases and pruritus decreased in 92% of the patients after parathyroidectomy. Soft tissue calcification showed improvement in 45% of cases. In conclusion, the subtotal parathyroidectomy or total parathyroidectomy with autotransplantation cause a rapid decrease of PTH level and the improvement of the clinical symptoms in patients with medical treatment resistant secondary hyperparathyroidism. Persistent hyperparathyroidism occurs in those cases when inadequate parathyroidectomy was performed.

A human epithelium-specific vector optimized in rat pneumocytes for lung gene therapy.

Gene therapy vectors based on mammalian promoters offer the potential for increased cell specificity and may be less susceptible than viral promoters to transcription attenuation by host cytokines. The human cytokeratin 18 (K18) gene is naturally expressed in the lung epithelia, a target site for gene therapies to treat certain genetic pediatric lung diseases. Our original vector based on the promoter and 5' control elements of K18 offered excellent epithelial cell specificity but relatively low expression levels compared with viral promoters. In the present study, we found that adding a stronger SV40 poly(A) signal boosted primary rat lung epithelial cell expression but greatly reduced cell specificity. Addition of a 3' portion of the K18 gene to our vector as a 3' untranslated region (UTR) improved epithelial cell-specific expression by reducing expression in lung fibroblasts. The effect of the 3' UTR was not related to gross differences in cell-specific splicing. A deletion variant of this UTR further increased lung epithelial cell expression while retaining some cell specificity. These data illustrate the possibilities for using 3' UTR to regulate cell-specific transgene expression. Our improved K18 vector should prove useful for pediatric lung gene therapy applications.

Determinants of the nuclear localization of the heterodimeric DNA fragmentation factor (ICAD/CAD).

Programmed cell death or apoptosis leads to the activation of the caspase-activated DNase (CAD), which degrades chromosomal DNA into nucleosomal fragments. Biochemical studies revealed that CAD forms an inactive heterodimer with the inhibitor of caspase-activated DNase (ICAD), or its alternatively spliced variant, ICAD-S, in the cytoplasm. It was initially proposed that proteolytic cleavage of ICAD by activated caspases causes the dissociation of the ICAD/CAD heterodimer and the translocation of active CAD into the nucleus in apoptotic cells. Here, we show that endogenous and heterologously expressed ICAD and CAD reside predominantly in the nucleus in nonapoptotic cells. Deletional mutagenesis and GFP fusion proteins identified a bipartite nuclear localization signal (NLS) in ICAD and verified the function of the NLS in CAD. The two NLSs have an additive effect on the nuclear targeting of the CAD-ICAD complex, whereas ICAD-S, lacking its NLS, appears to have a modulatory role in the nuclear localization of CAD. Staurosporine-induced apoptosis evoked the proteolysis and disappearance of endogenous and exogenous ICAD from the nuclei of HeLa cells, as monitored by immunoblotting and immunofluorescence microscopy. Similar phenomenon was observed in the caspase-3-deficient MCF7 cells upon expressing procaspase-3 transiently. We conclude that a complex mechanism, involving the recognition of the NLSs of both ICAD and CAD, accounts for the constitutive accumulation of CAD/ICAD in the nucleus, where caspase-3-dependent regulation of CAD activity takes place.

Cystic fibrosis mutations lead to carboxyl-terminal fragments that highlight an early biogenesis step of the cystic fibrosis transmembrane conductance regulator.

Inefficient delivery of the cystic fibrosis transmembrane conductance regulator (CFTR) to the surface of cells contributes to disease in the majority of cystic fibrosis patients. Analysis of cystic fibrosis-associated missense mutations in the first nucleotide binding domain (NBD1), including A455E, S549R, Y563N, and P574H, revealed reduced levels of mature CFTR with elevated levels of carboxyl-terminal polypeptide fragments of 105 and 90 kDa. These fragments appear early in biogenesis and degrade rapidly in four distinct cell types tested including the bronchial epithelial IB3-1 cell line. They were detected at highest levels with CFTRA455E where the 105-kDa fragment accounted for 40% of newly synthesized polypeptide but for only 20 and 7% of nascent wild type and mutant DeltaF508 proteins, respectively. The bands represent core- and unglycosylated forms of the same CFTR fragment supporting that precursor forms are correctly inserted into the membrane of the endoplasmic reticulum. Proteolytic cleavage would be predicted to occur on the cytosolic face of the endoplasmic reticulum within the NBD1-R domain segment, but pharmacological testing did not support involvement of the 26 S proteasome. The examined missense mutations in NBD1 manifest differently than the major mutant, DeltaF508, and highlight a critical conformational aspect of biogenesis of CFTR.