Multiplex PCR that can distinguish between immunologically cross- reactive serovar 3, 6, and 8 Actinobacillus pleuropneumoniae strains

We describe a highly sensitive and specific multiplex PCR, based on capsular loci and the species specific apxIV gene, that unequivocally differentiates serovar 3, 6, and 8 Actinobacillus pleuropneumoniae strains that are cross-reactive in conventional immunological tests.

Articular cartilage restoration in load-bearing osteochondral defects by implantation of autologous chondrocyte-fibrin constructs: an experimental study in sheep

Ovine articular chondrocytes were isolated from cartilage biopsy and culture expanded in vitro. Approximately 30 million cells per ml of cultured chondrocytes were incorporated with autologous plasma-derived fibrin to form a three-dimensional construct. Full-thickness punch hole defects were created in the lateral and medial femoral condyles. The defects were implanted with either an autologous 'chondrocyte-fibrin' construct (ACFC), autologous chondrocytes (ACI) or fibrin blanks (AF) as controls. Animals were killed after 12 weeks. The gross appearance of the treated defects was inspected and photographed. The repaired tissues were studied histologically and by scanning electron microscopy analysis. All defects were assessed using the International Cartilage Repair Society (ICRS) classification. Those treated with ACFC, ACI and AF exhibited median scores which correspond to a nearly-normal appearance. On the basis of the modified O'Driscoll histological scoring scale, ACFC implantation significantly enhanced cartilage repair compared to ACI and AF. Using scanning electron microscopy, ACFC and ACI showed characteristic organisation of chondrocytes and matrices, which were relatively similar to the surrounding adjacent cartilage. Implantation of ACFC resulted in superior hyaline-like cartilage regeneration when compared with ACI. If this result is applicable to humans, a better outcome would be obtained than by using conventional ACI.

Calculation of electronic surface states in superlattices via graph formulations

We propose a graph method for the analysis of electronic surface states in a complex basis superlattice terminated by surface with a multilayer clad. Using topology theory, we frame an energy equation for calculating the surface modes based on a graph model. Compared to the traditional methods, the present method does not have the problem of numerical instability for finding out the surface states of the superlattices. The other advantage is that the localized states are directly solved by the present method without spurious solutions, which usually exist in the solutions obtained by traditional methods. Numerical examples show removal of the spurious solutions by traditional methods may cause numerically instable and incorrect results.

Infection of HeLa cells by avian infectious bronchitis virus is dependent on cell status

To investigate the adaptation of avian infectious bronchitis virus (IBV) in a human cell line may be beneficial to understanding the potential mechanisms of coronavirus interspecies infection. The current study addressed the poor replication of IBV in the HeLa human cell line demonstrated in previous reports. We showed that IBV strains M41, H52, H120 and Gray could be propagated in HeLa cells with distinct cytopathic effect. The virus titre in freshly dispersed HeLa cells was 1000-fold higher than in cell monolayers. Trypsin was not the determinant for the viral replication, suggesting that the restriction of IBV replication in HeLa cells is the result of intracellular events rather than the binding to or fusion with host cells. These IBV strains replicated to an average titre of 10(3.4+/-0.2)/0.1 ml median tissue culture infectious doses in freshly dispersed HeLa cells and maintained this titre for the first 12 passages. Then an approximately 10-fold increase (10(4.20+/-0.19)/0.1 ml) occurred in passage 13, which was maintained to passage 16, after which there was another, bigger rise to 10(6.6+/-0.3)/0.1 ml in passage 17. This titre was maintained until passage 24 when the experiment was terminated. The IBV M41 S1 gene was amplified and sequenced for passages 0, 5 and 21. There was only one amino acid replacement in the S1 protein, in passage 21. The presence of sialic acid on HeLa cells contributed to efficient virus replication, while human aminopeptidase N was not involved in the infection. Haemagglutinin activity gradually reduced with increased passages. These results indicated that the virus adaptation would probably be determined by host cell modification such as receptor glycosylation and different receptor utilization instead of viral gene mutation.

Electronic minibands in complex basis superlattices: a numerically stable calculation

A numerically stable method for accurately determining the energy minibands of superlattices with arbitrary numbers of layers per cell is presented. Using a graph model with tangent and secant functions, we derive a set of concise and closed-form miniband edge equations for determining the miniband structure using topology theory. With the present method, it is not necessary to calculate the cosine of the Bloch phase, which may show a numerical overflow in calculation. Numerical results show that use of the miniband edge equations has better numerical stability than traditional methods in calculating the minibands of complex basis superlattices.

Endothelin-1 regulates parathyroid hormone expression of human parathyroid cells

OBJECTIVE

Parathyroid cells synthesize and release endothelin-1 (ET-1). ET-1 displays an in vitro inhibitory effect on basal parathyroid hormone (PTH) secretion and also counteracts PTH hypersecretion stimulated by low calcium. Such effects are further demonstrated in vivo, independent of the changes in calcitonin. We propose that ET-1 may regulate the pathogenesis of uremic hyperparathyroidism. However, this was not directly demonstrated in human parathyroid glands.

DESIGN

Hyperplastic parathyroid glands are obtained from the surgical operation for uremic hyperparathyroidism. Cells are isolated by enzyme digestion and treated with ET-1, and are assessed for PTH mRNA expression. PTH in the plasma and the medium is measured by a newly developed method to detect the whole PTH (1-84).

PATIENTS

Uremic patients with severe secondary hyperparathyroidism and ultrasonography-proved hypertrophy of parathyroid glands received elective surgical approaches under general anesthesia. The resected glands were immediately taken to the laboratory for fresh isolation.

MEASUREMENTS

Following ET-1 treatment, PTH mRNA expression is evaluated by RT-PCR method. ET-1 is detected with radioimmunoassay kit and PTH is measured by a new commercially available Duo PTH kit.

RESULTS

ET-1 exhibited a dose-dependent inhibitory effect (from 10(-12) - 10(-7) M) on PTH mRNA expression of parathyroid cells, either in the basal or in the low-calcium-stimulated states. Release of PTH into the medium is also gradually inhibited by the increase in ET-1 concentrations.

CONCLUSIONS

Our results demonstrate that ET-1 attenuates PTH mRNA expression in freshly isolated human parathyroid cells, and PTH release is also decreased. This result is consistent with our previously reported in vitro and in vivo experiments.

Decreased B cells and IgA-secreting B cells partially explain the high prevalence of IgA deficiency in dialysis patients

AIMS

We previously reported 2 hemodialysis (HD) patients with recurrent infections and selective immunoglobulin A deficiency (IgAD). We further demonstrated that serum IgA levels were lower and the prevalence of IgAD was higher in uremic patients. The exact mechanisms of IgAD in uremic patients largely remained unclear. In some patients, it was caused by anti-IgA antibody neutralization and subsequent destruction. We performed the present study to survey if there is any defect in IgA production.

MATERIALS AND METHODS

288 patients were initially included for examination of serum immunoglobulins. 16 normal persons, 16 dialysis patients without IgAD, and 12 dialysis patients with IgAD were enrolled after the initial examination. Blood was drawn into heparinized tubes. WBC counts and lymphocyte percentage were examined by a CBC counter. Lymphocytes were separated by the Ficoll-Paque method. Flow cytometry was utilized to isolate the B cell and IgA-secreting B cell after staining with CD 19 phycoerythrin and FITC-conjugated rabbit anti-human IgA antibody.

RESULTS

There is no significant difference between WBC counts or total lymphocyte counts of these 3 groups. However, we found a lower percentage of total lymphocyte counts in dialysis patients, either with or without IgAD. The total B cell numbers were lower in dialysis patients with IgAD. In addition, there were fewer IgA-secreting B cells in dialysis patients with IgAD.

CONCLUSION

Decreased B cell and IgA-secreting B cell counts are seen in uremic patients with IgAD. This, in turn, indicates that there might be a defect of IgA production in some patients, rather than IgA destruction by anti-IgA antibodies as seen in some other patients. Further study is needed to investigate the mechanisms of decreased B cells and IgA-secreting B cells.

A new technique for substernal colon transposition with a breast dissector: report of 39 cases

This paper investigates the effectiveness of the breast dissector to create a substernal space for oesophageal reconstruction. The surgeon must be extremely careful while dissecting the tissue below the sternum in order to avoid pneumothorax. The endoscopically assisted preparation of the substernal route is safe but it requires appropriate training. A retrospective study on 68 patients who underwent oesophageal reconstruction was done analysing the patients' records. In 39 cases, the breast dissector was used. In 29 cases, the substernal tunnel was created with hand dissection only. All 68 colon segments were successfully transferred in the two groups of patients. In all 39 the cases where the breast dissector was used no pneumothorax followed. In 10 (34%) patients of the control group pneumothorax occurred. Concluding, no more pneumothorax has occurred during the substernal oesophageal reconstruction since we started using the breast dissector.

Acute pancreatitis following antilymphocyte globulin therapy in a renal transplant recipient

Acute pancreatitis is a rare complication following OKT3 therapy, which to our knowledge has never been reported in patients treated with antilymphocyte globulin (ALG). We herein report a case of a kidney transplantation patient who developed acute pancreatitis 2 days after treatment with ALG for grade IIb acute rejection. The symptoms subsided after discontinuing this drug. Resumption of ALG therapy triggered another episode of acute pancreatitis. Therefore, the clinical course strongly suggests that ALG was the etiological factor of acute pancreatitis in this particular patient.

Sweet's syndrome as an initial presentation in systemic lupus erythematosus: a case report and review of the literature

Malar or discoid rash is the most frequent specific cutaneous lesion for systemic lupus erythematosus (SLE). Neutrophilic dermatosis as an initial presentation in SLE is unusual. We describe a 38-year old female patient who primarily suffered from erythematous tender plaques and fever. Examination of skin biopsy of the plaques showed dense neutrophilic infiltration in the dermis. Polyarthritis, heavy proteinuria, photosensitivity and positive antinuclear antibodies (ANA > 1:1280) concluded the diagnosis of SLE. The plaques disappeared completely after treatment with systemic corticosteroids. To our knowledge, this is the first reported SLE patient with Sweet's syndrome as the initial presentation in literature review.

7-84 parathyroid hormone fragments are proportionally increased with the severity of uremic hyperparathyroidism

AIMS

Recent progress in PTH assay has revealed that the intact PTH assay kit in current use does not differentiate between the truncated 7-84 PTH molecule and the 1-84 PTH molecule. In our series, we examined the effectiveness of a new PTH assay as a noninvasive method of evaluating severity of uremic hyperparathyroidism.

METHODS AND MATERIALS

Two hundred and seventy hemodialysis (HD) patients recruited from three HD centers were included and divided into subgroups according to the conventional iPTH assay results. Pre-dialysis blood samples were collected and subjected to two different PTH assays: "intact" PTH assay (iPTH) and "whole" PTH (wPTH) assay. Two biochemical markers of bone remodeling were also examined.

RESULTS

In all cases, PTH levels determined by the wPTH assay were in the average 32.3% lower than those determined by the iPTH assay. The difference of the results of the two PTH assay methods, which indicated the portion of 7-84 PTH fragments of the total PTH molecules measured with the iPTH assay, was gradually increased while the severity of uremic hyperparathyroidism increased. Biochemical markers of bone formation/resorption showed a similar change.

CONCLUSION

The portion of the 7-84 PTH fragments and markers of increased bone turnover increased in proportion to the severity of uremic hyperparathyroidism. This finding disproves the hypothetical role of 7-84 PTH fragments alone as the noninvasive marker of low-turnover bone disease in HD patients.

Exaggerated relative nasal-temporal asymmetry of macular capillary blood flow in patients with clinically significant diabetic macular oedema

AIMS

To compare the macular capillary blood flow of patients with clinically significant diabetic macular oedema (DMO) with that of non-diabetic subjects and to determine the relation between blood flow and capillary leakage in patients with DMO.

METHODS

The sample comprised 45 non-diabetic subjects (mean age 59 years) and 18 type 2 patients with clinically significant DMO (mean age 60 years). Macular capillary blood flow measurements were acquired using the Heidelberg retina flowmeter (HRF) and a 10 degrees x2.5 degrees scan field centred on the fovea. Fluorescein angiography was undertaken on each of the diabetic patients after the completion of HRF measurements.

RESULTS

Temporal macular capillary blood flow was significantly lower for the patients with clinically significant DMO compared with age matched non-diabetic subjects (ANCOVA, p = 0.0011) while relative nasal-temporal asymmetry of macular capillary blood flow was significantly higher (p = 0.0125). Nasal-temporal asymmetry of macular capillary blood flow was significantly higher for the patients with DMO and capillary leakage within the scan area (two tailed t test, p = 0.0071). Macular capillary blood flow was always lower in areas of DMO and capillary leakage.

CONCLUSION

Capillary blood flow was reduced in areas of DMO and capillary leakage, suggesting the presence of a localised perturbation of capillary blood flow regulation.

Induction of matrix metalloproteinase-9 in mice during Toxocara canis larvae migration

The relationships between inflammation in organs with Toxocara canis larval migration and matrix metalloproteinase-9 (MMP-9) were investigated following the infection of mice with 1,000 infective eggs. Gelatinase activity was defined by gelatin zymography, optimum pH, inhibitor specificity and Western blot analysis. MMP-9 activity was present in the lungs, liver, muscles, and brain during T. canis larval migration. This enzyme had a molecular weight of about 94 kDa and showed maximum activity in the pH range of 6-8. The increased MMP-9 proteinases coincided with larval recovery and the degree of inflammation among the four organs. These results suggest that MMP-9 may be associated with the inflammatory reaction to larval toxocariasis during early migration, and may therefore be a useful marker during T. canis larvae migration.

Dehydroepiandrosterone suppresses interleukin 10 synthesis in women with systemic lupus erythematosus

OBJECTIVE

To study the effects of dehydroepiandrosterone (prasterone, DHEA) 200 mg/day on cytokine profiles in adult women with active systemic lupus erythematosus (SLE).

METHODS

In a double blind, randomised, placebo controlled study conducted as part of a larger multicentre study, 30 adult women with active SLE received oral DHEA 200 mg/day or placebo for 24 weeks. Baseline prednisone (<10 mg/day) and other concomitant SLE medications were to remain constant. The levels of cytokines including interleukin (IL) 1, IL2, interferon gamma, IL4, and IL10 were determined by ELISA. The mean change from baseline to 24 weeks of therapy was analysed.

RESULTS

The two groups (DHEA n = 15; placebo n = 15) were well balanced for baseline characteristics. Only IL1beta and IL10 could be detected in the serum of lupus patients; however, there was no significant mean (SD) difference in serum IL1beta before and after treatment (9.94 (8.92) v 9.20 (6.49) pg/ml). IL10 demonstrated a greater and significant reduction from baseline (9.21 (9.66) to 1.89 (1.47) pg/ml in the DHEA treatment group).

CONCLUSIONS

In a 24 week study of adult Chinese women with mild to moderate SLE, treatment with DHEA 200 mg once daily resulted in significant reduction of serum levels of IL10. This finding may suggest why DHEA could significantly reduce lupus flares.

Flap prefabrication - the bridge between conventional flaps and tissue-engineered flaps

Flap prefabrication is one of the most exciting areas in Plastic Surgery because of its bridging role between conventional reconstructive surgery and tissue engineering. Using this technique,tissues such as bone, cartilage, skin and muscle can be preassembled to form precise composites that will fit any defect. In pre-lamination, for example, an ear may be created by burying cartilage underneath forearm skin and later harvested as a skin-cartilage composite free flap to replace the missing part. Vascular induction is yet another means of customising flaps where new blood supply is introduced to create transplantable tissue. For example, bone chips wrapped in avascular carrier such as muscle can become vascularised grafts. Our experiment describes jejunal prefabrication in a rat model using the same technique. Intestinal segments wrapped in muscle flaps become independent of their mesenteric blood supply by "parasitising" on the muscle's blood supply. This idea arose from our initial observations that intestinal segments transferred to the neck to reconstruct the oesophagus could survive accidental disruption of the pedicle if sufficient time had elapsed. Clearly, the bowel had picked up new blood supply from its bed. Subsequently, jejunal prefabrication was used to reconstruct the oesophagus in a patient in whom there were no recipient vessels for free jejunal transfer. The pedicled latissimus dorsi muscle flap was used as a carrier for the jejunum. Another application of this idea could be in the area of allogeneic trachea or pancreatic transplantation, since present-day techniques have yet to overcome problems such as insufficient vascularity and unpredictable transplant survival. Future applications incorporating biomaterials and cultured cells will usher in the era of tissue-engineered flaps.

Aloe-emodin induced in vitro G2/M arrest of cell cycle in human promyelocytic leukemia HL-60 cells

In this study, we have evaluated the chemopreventive role of aloe-emodin in human promyelocytic leukemia HL-60 cells in vitro by studying the regulation of proliferation, cell cycle and apoptosis. Aloe-emodin inhibited cell proliferation and induced G2/M arrest and apoptosis in HL-60 cells. Investigation of the levels of cyclins B1, E and A by immunoblot analysis showed that cyclin E level was unaffected, whereas cyclin B1 and A levels increased with aloe-emodin in HL-60 cells. Investigation of the levels of cyclin-dependent kinases, Cdk1 and 2, showed increased levels of Cdk1 but the levels of Cdk2 were not effected with aloe-emodin in HL-60 cells. The levels of p27 were increased after HL-60 cells were cotreated with various concentrations of aloe-emodin. The increase of the levels of p27 may be the major factor for aloe-emodin to cause G2/M arrest in these examined cells. Flow cytometric assays and DNA fragmentation gel electrophoresis also confirmed aloe-emodin induced apoptosis in HL-60 cells. The levels of caspase-3 were increased after HL-60 cells were cotreated with 10 microM aloe-emodin for 12, 24, 48, and 72 hours. Taken together, aloe-emodin therefore appears to exert its anticarcinogenesis properties by inhibiting proliferation and inducing cell cycle arrest and apoptosis underwent activation of caspase-3 in human leukemia HL-60 cells.

RH locus contraction in a novel Dc-/D-- genotype resulting from separate genetic recombination events

BACKGROUND

The rare phenotypes Dc- and D-- lack the expression of E/e and CcEe antigens, respectively; their cotransmission in a single family has not been reported.

STUDY DESIGN AND METHODS

Six members of a Chinese family with two exhibiting the Dc- phenotype were studied using standard serologic methods. Rh genotypes were analyzed by Southern blot, and RH loci, by exon PCR. Rh transcripts were characterized by gene-specific RT-PCR and sequencing.

RESULTS

Although Rh typing detected two members as Dc- homozygotes, RFLP analysis and exon PCR showed them to be Dc- heterozygotes with a partial deletion of RHCE. cDNA sequencing showed the expression in the family of normal RHD and RHCe as well as hybrid transcripts, RHD(1-9)/RHCE(10) and RHCE(1-3)/RHD(4-10). Thus, the Dc- members had the genotype of Dc-/ D-- and expressed both hybrid genes that were inherited from their parents, respectively.

DISCUSSION

This is the first demonstration in a family that the Dc- and D-- complexes neither are linked with a normal RHD or RHCE gene. The segregation of these two different hybrid genes with single break points suggests their independent genetic origin and provides molecular insights into the dynamic nature of genomic rearrangements leading to RH locus contraction.

Design and testing of a fluorescence glucose sensor which incorporates a bioinductive material

One main hurdle in the development of implantable biosensors is that their lifetime is limited by scar tissue formation around the implant. One way to ameliorate this issue would be to use a bioinductive coating to allow normal tissue ingrowth around the sensor. Here, we report design, development and in vitro testing of a prototype fluorescence-based glucose sensor that incorporates a bioinductive material at its tip. Glucose is sensed via a fluorescence-based assay system (Amplex reagent) which is confined to a small chamber separated from the bulk glucose solution by a semipermeable membrane. Excitation is provided by a 530 nm laser, while the emitted light is detected by a photomultiplier tube. In vitro testing of this prototype was done in the presence and absence of a bioinductive material covering the membrane at the sensor/solution interface. In response to a step change in glucose concentration, the output of the sensor increased linearly over time due to accumulation of fluorescent marker molecules as glucose diffused into the recording chamber. The slope of this response increased linearly with increasing glucose concentration, with a sensitivity if 2.1 x 10(-4) V/min per ml glucose/dl solution. The presence of the bioinductive layer did not alter the function of the sensor at the lowest glucose concentrations tested, although responses to higher concentrations saturated, presumably because of depletion of the Amplex reagent within the chamber. In summary, we report that the use of a bioinductive material in an implantable biosensor does not appreciably alter sensor function.

Ruptured renal microaneurysms complicated with a retroperitoneal abscess for a patient with systemic lupus erythematosus

Renal artery aneurysm is extremely rare among patients with systemic lupus erythematosus.(SLE). Herein, we report on a 22-year-old male lupus patient who presented with acute abdominal pain, anemia and subsequent hypertension. Abdominal computed tomography revealed a peri-renal hematoma over the right kidney. A renal angiography revealed bilateral renal microaneurysms. The patient subsequently developed a right-side retroperitoneal abscess 4 weeks after hematoma formation and received an emergent laparotomy with drainage. Subsequent culture ofthe abscess-derived fluid revealed the presence of Proteus mirabilis and Escherichia coli. Following appropriate antipyretic and immunosuppressive drugs therapy, the patient recovered successfully. To the best of our knowledge, this is the first report of SLE associated with a retro-peritoneal abscess probably secondary to a ruptured renal microaneurysm.

Correlation of a scanning laser derived oedema index and visual function following grid laser treatment for diabetic macular oedema

AIM

To correlate change of an oedema index derived by scanning laser tomography with change of visual function in patients undergoing grid laser photocoagulation for clinically significant diabetic macular oedema (DMO).

METHODS

The sample comprised 24 diabetic patients with retinal thickening within 500 micro m of the fovea. Inclusion criteria included a logMAR visual acuity of 0.25, or better. Patients were assessed twice before a single session of grid laser treatment and within 1 week of, and at 1, 2, 4, and 12 weeks after, treatment. At each visit, patients underwent logMAR visual acuity, conventional and short wavelength automated perimetry (SWAP), and scanning laser tomography. Each visual function parameter was correlated with the mean oedema index. The mean oedema index represented the z-profile signal width divided by the maximum reflectance intensity (arbitrary units). A Pearson correlation coefficient (Bonferroni corrected) was undertaken on the data set of each patient.

RESULTS

13 patients exhibited significant correlation of the mean oedema index and at least one measure of visual function for the 10 degrees x 10 degrees scan field while 10 patients correlated for the 20 degrees x 20 degrees scan field. Seven patients demonstrated correlation for both scan fields. Laser photocoagulation typically resulted in an immediate loss of perimetric sensitivity whereas the oedema index changed over a period of weeks. Localised oedema did not impact upon visual acuity or letter contrast sensitivity when situated extrafoveally.

CONCLUSIONS

Correlation of change of the oedema index and of visual function following grid laser photocoagulation was not found in all patients. An absence of correlation can be explained by the localised distribution of DMO in this sample of patients, as well as by differences in the time course of change of the oedema index and visual function. The study has objectively documented change in the magnitude and distribution of DMO following grid laser treatment and has established the relation of this change to the change in visual function.

A new incision for surgery on tendo Achillis using a distally-based fasciocutaneous flap

The consequences of breakdown of the wound after surgery to tendo Achillis are considerable. Complex surgery is often required to reconstruct the tendon and to provide soft-tissue cover. We describe a new incision which approaches the tendon by using a distally-based fasciocutaneous flap. This reduces the risk of breakdown of the wound since it avoids making an incision directly over the tendon, provides good exposure, and maintains the vascularity of the skin overlying the tendon.

Predictive factors for skin telangiectasia following post-mastectomy electron beam irradiation

This study evaluated the predictive factors associated with skin telangiectasia following post-mastectomy electron beam irradiation of the chest wall and regional lymph nodes in patients with breast cancer. From July 1987 to December 1994, 120 women with stages II and III breast cancer received electron beam irradiation following modified radical mastectomy. Doses of 50-50.4 Gy per 25-28 fractions were given to the chest wall (with bolus), the internal mammary nodes, the supraclavicular nodes and the axillary lymph nodes using a 12 MeV or 15 MeV single portal electron beam. 19 patients received an additional 10-16 Gy boost to the surgical scar using a 9 MeV electron beam. Univariate and multivariate analyses for the development of skin telangiectasia showed 5- and 7-year actuarial rates of telangiectasia to be 59% and 72%, respectively. In univariate analysis, an additional surgical scar boost (p=0.023) as well as no treatment interruption (p=0.028) were associated with a significantly increased risk of skin telangiectasia. In multivariate analysis, the only significant independent factor for the development of skin telangiectasia was surgical scar boost (p=0.026); no treatment interruption showed a trend but did not achieve significance (p=0.051). Thus, patients given an additional boost to the surgical scar are more likely to develop skin telangiectasia. Shorter treatment courses may result in a higher probability of skin telangiectasia following electron beam irradiation.