Spiral computed tomographic angiography--a new technique for evaluation of vascular access in hemodialysis patients

Spiral computed tomographic angiography (CTA), a new noninvasive imaging technique, was used to study 10 arteriovenous fistulas (AVF) in 9 hemodialysis patients. Digital subtraction angiography (DSA) was also performed as a gold standard for comparison. AVF stenosis was graded by a four-point scale: grade 0, well patency of supplying artery, anastomosis and drainage vein; grade 1, < 50% stenosis; grade 2, 50-70% stenosis; grade 3, 70-99% stenosis, and grade 4, total occlusion. We found CTA correlated closely to DSA in detecting both stenosis and dilatation of AVF and it spared all the shortcomings of DSA. CTA has the potential to be alternative for imaging of dialysis fistulas. Further studies will be performed to specify the role of CTA images in the assessment of the hemodialysis vascular access.

Inappropriate antidiuresis associated with pituitary adenoma--mechanisms not involving inappropriate secretion of vasopressin

We report an unusual case of inappropriate antidiuresis with undetectable vasopressin in an elderly man presenting with confusion due to severe hyponatremia. Further investigations led to the diagnosis of non-functional pituitary macroadenoma. The patient had normal thyroid and adrenal function. The abnormal water balance resolved promptly after transsphenoidal removal of the tumor, confirmed by a repeat water loading test. We conclude that inappropriate antidiuresis in the absence of excess vasopressin secretion may implicate mass effect from an underlying pituitary tumor.

Mycotic aneurysm of the abdominal aorta in a patient undergoing hemodialysis: an unusual complication of Staphylococcus aureus bacteremia

When Staphylococcus aureus is repeatedly positive in blood cultures even under effective antibiotics therapy (vancomycin, teicoplanin, or rifampin), computed tomography scan and sonography should be performed early to exclude mycotic aneurysm of the deeply seated arteries, especially in patients with abdominal aortic calcification. Before 1990, the most common causative organism of suprarenal aortic mycotic aneurysm was Salmonella; since 1990, it has been gram-positive cocci (i.e., Streptococcus and Staphylococcus) rather than gram-negative bacilli (i.e., Salmonella), possibly because of the more invasive procedures performed in clinical settings, but this hypothesis needs further investigation.

TT virus infection among hemodialysis patients at a medical center in Taiwan

Although the association between TT virus (TTV) infection and hepatitis is controversial, the high prevalence of TTV infection in healthy blood donors and even higher rate among frequently transfused patients poses a potential threat to public health and clinical care. In addition, there is a lack of data concerning the prevalence and mode of transmission of TTV infection in different subpopulations in Taiwan. In the present study, we investigated the prevalence of TTV infection in 111 uremic patients receiving regular hemodialysis in a single hospital in Taiwan. Blood samples were collected and analyzed using a seminested polymerase chain reaction (PCR) designed to amplify a 271 base-pair DNA fragment. The results show that the overall TTV positive rate in uremic patients in our hospital was 61% (68/111), which was much higher than the reported TTV prevalence rate among the normal population (ranging from 1%-12%). The results of analysis of the demographic and clinical characteristics of the patients indicate that blood transfusion may play an important role in TTV transmission (p < 0.05). In addition, the hepatitis B positive rate was significantly lower in TTV positive patients. However, liver function tests were not significantly different between TTV positive and TTV negative patients. The results of the present study suggest that blood transfusion plays an important role in TTV transmission in uremic patients.

Genetics of gametophyte biogenesis in Arabidopsis

The identification of several mutations and genes involved in sporogenesis and gametogenesis has initiated a genetic framework for understanding gametophyte biogenesis. Recent advances include the molecular characterization of genes required for sporocyte formation and meiosis. These studies have revealed some unexpected interactions linking development of sporophytic cells and tissues with initiation and progression of gametophyte development in angiosperms.

Impact of hepatitis B and C virus infection on the outcome of kidney transplantation in Chinese patients

BACKGROUND

There has been improvement in kidney transplantation over the years; however, the impact of hepatitis B and C virus (HBV, HCV) infection on the long-term outcome of kidney transplant is still controversial.

METHODS

A total of 113 patients who received renal allografts from 1986 to 1998 were analyzed. Nine were positive for both hepatitis B surface antigen (HBsAg) and antibody to HCV (anti-HCV) (Group 1), 20 were HBsAg-positive and anti-HCV-negative (Group 2), 30 were HBsAg-negative and anti-HCV-positive (Group 3) and 54 were negative for both markers (Group 4). The outcome and survival were compared among the four groups of patients.

RESULTS

The mean follow-up period was 5.1 +/- 3.2 years (range, 0.5-13 years) for all patients. Group 2 patients had significantly higher liver-related complications (35% vs 0%, p < 0.0001) and liver-related deaths (20% vs 0%, p = 0.004) than did Group 4 patients. Among all, four HBsAg-positive patients had fulminant hepatitis and died within two years of transplantation. Three (Group 2) of the patients who died were seropositive for hepatitis B e antigen and/or HBV DNA and none had a history of or positive serologic marker to indicate hepatitis of other etiologies. The remaining patient (Group 1) had evidence of superinfection of HCV. Liver cirrhosis occurred in one, two and one patient in Groups 1, 2 and 3, respectively, and hepatocellular carcinoma occurred in two and one patient in Groups 2 and 3, respectively. Despite high liver-related mortality in HBV-infected patients, paradoxically, no significant differences among the four groups in the long-term graft and patient survivals were demonstrated. The presence of HBsAg or anti-HCV was not associated with a poor prognosis of survival as determined by Cox regression analysis.

CONCLUSIONS

HBV or HCV infection is not a contraindication to kidney transplantation in Chinese patients. However, it should be noted that serious liver-related complications may occur and limit survival in HBV- and/or HCV-infected patients after kidney transplantation.

Hantavirus infection in Taiwan: the experience of a geographically unique area

Hantaviruses are rodent-borne viruses, and they, mainly the Hantaan (HTN) serotype, are the causative agents of a group of febrile nephropathies known as "hemorrhagic fever with renal syndrome (HFRS). " Despite the fact that HFRS is frequently reported in China, with an annual incidence of 50,000-100,000 cases, one puzzling observation that no local case of HFRS has been confirmed in Taiwan has yet to be explained. We hypothesized that the hantavirus strain prevailing in Taiwan mainly belongs to the mild strain, the Seoul (SEO) strain, and the absence of severe disease was related to the absence of HTN. To test these hypotheses, this epidemiologic study was performed, including a seroprevalence survey and phylogenetic analysis on hantavirus isolated from the rodent population trapped in major seaports, rural, and mountainous areas of Taiwan. This study also included rodents and viruses from two isolated islands, Kinmen and Matzu, which are geographically adjacent to the east coast of mainland China. There were a total of 5,461 rodents of 16 species captured, and R. norvegicus was the most common species, with an antibody prevalence much higher in international seaports (20%) than in rural regions (approximately 5%) and intermediate in some domestic seaports. By reverse transcriptase polymerase chain reaction (RT-PCR), 33.9% of the seropositive R. norvegicus were found to have amplifiable hantavirus sequences in their lung tissues, and subsequent phylogenetic analyses indicated that almost all hantavirus in Taiwan was most closely related to the prototype SEO strain, and no HTN strain was recovered from any rodent species indigenous to Taiwan. The seroprevalence of SEO infection in R. norvegicus on Kinmen and Matzu was also different from that in southern provinces of China but closely resembled that in seaports in Taiwan, and the SEO identified was genetically linked to Taiwanese SEO strains. These results substantiate our hypotheses, and suggest that the epidemiology of hantavirus infection in Taiwan are different from that in China, where the HTN and SEO strains and HFRS concurrently prevail.

Simultaneous determination of polycarboxylic acids by capillary electrophoresis with a copper electrode

The simultaneous determination of polycarboxylic acids including oxalic acid, citric acid, malonic acid, malic acid, tartaric acid, aspartic acid and glutamic acid was achieved by capillary electrophoresis with a copper disk electrode (d = 200 microm). In the system. 0.2 mmol/l cetylpridinium bromide (CPB) was used as an electroosmotic flow (EOF) modifier to reverse the direction of EOF. The effects of the solution pH and CPB concentration on separation were evaluated to achieve the optimum separation conditions. At the working potential of +0.14 V (vs. saturated calomel electrode), the calibration curves for all polycarboxylic acids studied were linear with 2 approximately 3-orders of magnitude and all the detection limits (S/N = 3) were below 15 fmol except malonic acid. Furthermore, the oxalic and citric acids in urine were successfully separated and determined with high sensitivity.

Renal allograft dysfunction associated with rifampin-tacrolimus interaction

OBJECTIVE

To report an interaction between tacrolimus and rifampin with subsequent adverse effects on renal allograft function.

CASE SUMMARY

A 61-year-old Chinese man received a cadaveric renal transplant in 1991. Progressive deterioration of allograft function developed during the following six years while the patient was receiving cyclosporine and prednisolone. In January 1998, tacrolimus was substituted for cyclosporine for late biopsy-proven graft rejection, with target trough blood concentrations between 5 and 8 ng/mL. After conversion, serum creatinine fell to 2.0 mg/dL; the nadir was reached within one year. At the same time, rifampin was instituted for controlling tuberculosis and empiric fluconazole was discontinued. Twelve days later, the patient's serum creatinine concentration rose to 2.9 mg/dL and tacrolimus concentration fell to 1.5 ng/mL, along with oliguria. These findings suggested acute rejection, which was successfully reversed by steroid therapy. However, more than a tenfold increase in the tacrolimus dosage was required to maintain the same concentrations during subsequent months, accompanied by an increase in serum creatinine (from 2.0 to 2.6 mg/dL) and decrease in urine excretion. Biopsy at this time demonstrated acute rejection (Banff I), chronic allograft nephropathy (Banff II), and suspected tacrolimus nephrotoxicity. After unsuccessful methylprednisolone recycling, mycophenolate mofetil was introduced to control rejection and facilitate reduction of the tacrolimus dosage to minimize its nephrotoxicity.

CONCLUSIONS

As a potent CYP3A4 isoenzyme inducer, rifampin coadministration caused the abrupt decrease in tacroiimus blood concentrations, leading to an approximate tenfold increase in its daily dose, which may be important to subsequent allograft dysfunctions.

Analysis of flanking sequences from dissociation insertion lines: a database for reverse genetics in Arabidopsis

We have generated Dissociation (Ds) element insertions throughout the Arabidopsis genome as a means of random mutagenesis. Here, we present the molecular analysis of genomic sequences that flank the Ds insertions of 931 independent transposant lines. Flanking sequences from 511 lines proved to be identical or homologous to DNA or protein sequences in public databases, and disruptions within known or putative genes were indicated for 354 lines. Because a significant portion (45%) of the insertions occurred within sequences defined by GenBank BAC and P1 clones, we were able to assess the distribution of Ds insertions throughout the genome. We discovered a significant preference for Ds transposition to the regions adjacent to nucleolus organizer regions on chromosomes 2 and 4. Otherwise, the mapped insertions appeared to be evenly dispersed throughout the genome. For any given gene, insertions preferentially occurred at the 5' end, although disruption was clearly possible at any intragenic position. The insertion sites of >500 lines that could be characterized by reference to public databases are presented in a tabular format at http://www.plantcell. org/cgi/content/full/11/12/2263/DC1. This database should be of value to researchers using reverse genetics approaches to determine gene function.

Glomerular epithelial-myofibroblast transdifferentiation in the evolution of glomerular crescent formation

BACKGROUND

Glomerular cellular crescents consist of epithelial cells and macrophages, which can undergo an irreversible process of fibrous organization. However, the origin of the fibroblast-type cells that mediate this fibrous organization is unclear.

METHODS

This study examined glomerular epithelial- myofibroblast transdifferentiation (GEMT) in the formation and evolution of glomerular crescents in two distinct rat models of glomerulonephritis: 5/6 nephrectomy and antiglomerular basement membrane (GBM) disease.

RESULTS

Early in the course of both disease models, and prior to crescent formation, immunohistochemistry staining and in-situ hybridization demonstrated de novo expression of alpha-smooth-muscle actin (alpha-SMA), a marker of smooth muscle cells and myofibroblasts, by glomerular parietal epithelial cells (GPEC). The expression of alpha-SMA by GPEC was accompanied by a loss of E-cadherin staining, a marker of epithelial cells. At this early stage of GEMT, ultrastructural studies identified the presence of characteristic actin microfilaments and dense bodies within GPEC which retained a normal epithelial morphology with apical-basal polarity and microvilli. A late stage of transdifferentiation was seen in fibrocellular crescents. In this case, GPEC attached to intact segments of the capsular basement membrane contained large bundles of actin microfilaments throughout the cell, and this was accompanied by a loss of polarity, microvilli, and tight junctions. There was a significant correlation between the presence of alpha-SMA(+) GPEC and glomerular crescent formation. Cellular crescents contained small numbers of alpha-SMA(+) myofibroblasts. These cells become the dominant population in fibrocellular crescents, which was associated with marked local proliferation. Relatively few alpha-SMA(+) myofibroblasts remained in fibrotic/organizing crescents. Most cells within cellular and fibrocellular crescents expressed transforming growth factor-beta (TGF-beta) and basic fibroblast growth factor (FGF-2), suggesting that these growth factors may regulate this GEMT process during the evolution of glomerular crescents.

CONCLUSIONS

This study provides the first phenotypic and morphological evidence that glomerular epithelial-myofibroblast transdifferentiation participates in the formation and evolution of glomerular crescents.

The SPOROCYTELESS gene of Arabidopsis is required for initiation of sporogenesis and encodes a novel nuclear protein

The formation of haploid spores marks the initiation of the gametophytic phase of the life cycle of all vascular plants ranging from ferns to angiosperms. In angiosperms, this process is initiated by the differentiation of a subset of floral cells into sporocytes, which then undergo meiotic divisions to form microspores and megaspores. Currently, there is little information available regarding the genes and proteins that regulate this key step in plant reproduction. We report here the identification of a mutation, SPOROCYTELESS (SPL), which blocks sporocyte formation in Arabidopsis thaliana. Analysis of the SPL mutation suggests that development of the anther walls and the tapetum and microsporocyte formation are tightly coupled, and that nucellar development may be dependent on megasporocyte formation. Molecular cloning of the SPL gene showed that it encodes a novel nuclear protein related to MADS box transcription factors and that it is expressed during microsporogenesis and megasporogenesis. These data suggest that the SPL gene product is a transcriptional regulator of sporocyte development in Arabidopsis.

Intravenous ascorbic acid as an adjuvant therapy for recombinant erythropoietin in hemodialysis patients with hyperferritinemia

BACKGROUND

Inadequate iron mobilization and defective iron utilization may cause recombinant erythropoietin (rEPO) hyporesponsiveness in hemodialysis (HD) patients with iron overload. We have demonstrated that intravenous ascorbic acid (IVAA), but not intravenous iron medication, can effectively circumvent the functional iron-deficient erythropoiesis associated with iron overload in HD patients. However, it is uncertain whether all HD patients with hyperferritinemia will consistently respond to IVAA and which index may indicate functional iron deficiency in the special entity. Therefore, a prospective study was conducted to establish the guidelines for IVAA adjuvant therapy.

METHODS

Sixty-five HD patients with serum ferritin levels of more than 500 microgram/liter were recruited and divided into the control (N = 19) and IVAA (N = 46) groups. IVAA patients with a hematocrit (Hct) of less than 30% received 300 mg of ascorbic acid three times per week for eight weeks. Controls had a Hct of more than 30% and did not receive the adjuvant therapy. Red blood cell and reticulocyte counts, iron metabolism indices, erythrocyte zinc protoporphyrin (E-ZPP), and the concentrations of plasma ascorbate and oxalate were examined before and following the therapy.

RESULTS

Thirteen patients (four controls and nine IVAA patients) withdrew by the end of the study. Eighteen patients had a dramatic response to IVAA with a significant increase in their hemoglobin and reticulocyte index and a concomitant 24% reduction in rEPO dose after eight weeks. This paralleled a significant rise in serum iron and transferrin saturation (TS) and a fall in E-ZPP and serum ferritin (baselines vs. 8 weeks, serum iron 68 +/- 37 vs. 124 +/- 64 microgram/dl, TS 27 +/- 10 vs. 48 +/- 19%, E-ZPP 123 +/- 44 vs. 70 +/- 13 micromol/mol heme, and serum ferritin 816 +/- 435 vs. 587 +/- 323 microgram/liter, P < 0. 05). Compared with responders, mean values of hemoglobin, rEPO dose, iron metabolism parameters, and E-ZPP showed no significant changes in controls (N = 15) and in non-responders (N = 19). Thirty-seven patients (18 responders and 19 non-responders) were further analyzed by receiver operating characteristic curves to seek the criteria for prediction of a response to IVAA treatment. The results showed that E-ZPP at a cut-off level of more than 105 micromol/mol heme and TS at a level of less than 25% were more specific to confirm the status of functional iron deficiency in iron-overloaded patients. The two criterion values had the highest accuracy to predict a response to treatment.

CONCLUSIONS

Functional iron-deficient erythropoiesis plays a role in rEPO-hyporesponsive anemia in HD patients with hyperferritinemia. IVAA may be an adjuvant therapy for rEPO in these patients, and E-ZPP of more than 105 micromol/mol heme and TS of less than 25% should be used to guide the IVAA treatment.

Tec kinase is involved in transcriptional regulation of IL-2 and IL-4 in the CD28 pathway

The Tec protein tyrosine kinase (PTK) family includes Btk, Itk/Tsk/Emt, Tec, Rlk/Txk and Bmx, which are involved in signals mediated by various surface receptors. We have previously found (W.-C. Yang et al., J. Biol. Chem. 1999. 274: 607) that Tec is involved in T cell signaling in a way distinct from Itk. However, little is known about the role of Tec in regulation of cytokine expression in the CD28 pathway. Here, we show in heterologous COS-7 cells that co-expression of Src family kinases such as Lck increases Tec activation or CD28-mediated Tec activation, whereas co-expression of kinase-dead Lck blocks Tec activation or CD28-mediated Tec activation. These data suggest that CD28 activates Tec via Src family PTK. As is the case for the IL-2 promoter, transcription of the IL-4 promoter is enhanced by overexpression of wild-type Tec but inhibited by overexpression of a kinase-dead version of Tec following CD28 activation. These results imply that Tec can modulate transcription of Th1 and Th2 cytokines in a kinase-dependent manner. Consistent with the hypothesis postulated above that Lck can regulate Tec activation, overexpression of kinase-dead Lck can block Tec-induced cytokine expression following CD28 ligation.

Is serum transferrin receptor a sensitive marker of iron repletion in patients with iron-deficiency anemia and hemodialysis patients?

BACKGROUND

Serum transferrin receptor (sTfR) concentration has been recognized as a reliable laboratory indicator of iron deficiency in recent years. But its response to iron supplementation has not been investigated.

METHODS

We evaluated the sTfR concentrations in 15 patients diagnosed with iron-deficiency anemia, in 30 patients receiving maintenance hemodialysis (HD) with iron repletion and in 31 healthy controls. The serial changes of sTfR concentration and their correlation with serum ferritin in patients with iron deficiency under iron repletion were also examined in three patients.

RESULTS

In patients with iron-deficiency anemia, the sTfR concentration was 5.6 +/- 2.4 mg/ml, significantly higher than that in the control group (1.8 +/- 0.4 mg/ml) and patients receiving maintenance HD with iron repletion (1.7 +/- 0.5 mg/ml). The three patients with iron-deficiency anemia who received eight to 16 weeks of iron supplementation showed steady and significant decreases in sTfR concentration and significant increases in serum ferritin and transferrin saturation. However, the decreases in sTfR concentration did not occur immediately, as did the increases in serum ferritin and transferrin saturation, following iron repletion. There was a four-week delayed response in the decrease of sTfR concentrations as measured against serum ferritin and transferrin saturation.

CONCLUSIONS

sTfR concentration may not be as effective as an early index of iron repletion compared with serum ferritin and transferrin saturation.

Descending mesocolon defect herniation: case report

Internal hernia, herniation of the internal organs through defects in the intraabdominal cavity, is rare. Due to the rarity of this pathology and lack of the specific symptoms and signs, early diagnosis and treatment are always stressful to the clinician and misdiagnoses may occur in the emergency room. The prognosis of a patient with uncomplicated internal hernia is excellent. We report a 21-year-old Chinese man with internal herniation through a defect of mesocolon, presented as an impalpable abdominal mass which was shown only on imaging studies. In addition to the typical whirlpool pattern, a huge solid mass between the pancreatic tail and stomach was found under computed tomography (CT) scan. The major symptoms were intermittent epigastralgia and abdominal fullness that had bothered him for years. Physical examination results showed only mild epigastric tenderness. Computed tomography scans and exploratory laparotomy of the abdomen played vital roles during diagnosis. The herniated organ was a portion of jejunum with partial small intestinal obstruction.

Erythropoietin hyporesponsiveness: from iron deficiency to iron overload

Iron deficiency is the most frequently encountered cause of suboptimal response to recombinant human erythropoietin (rHuEPO). Carefully assessing iron status is of paramount importance in chronic renal failure patients prior to or during rHuEPO therapy. Because there is great need for iron in the EPO-stimulated erythroid progenitors, it is essential that serum ferritin and transferrin saturation levels should be maintained over 300 microg/liter and 30%, respectively. Investigators have shown that oral iron is unlikely to keep pace with the iron demand for an optimal rHuEPO response in uremics. Therefore, patients with iron deficiency will always require intravenous iron therapy. The early and prompt iron supplementation can lead to reductions in rHuEPO dose and hence cost. After the iron deficiency has been corrected or excluded, we must remember all of the possible causes of hyporesponsiveness in every rHuEPO-treated patient. As dose requirements vary, it is not clear which dose of rHuEPO causes this hyporesponsiveness. However, if the patient with iron repletion does not respond well after the induction period, the major causes blunting the response to rHuEPO should be investigated. Most factors are reversible and remediable, except resistant anemia associated with hemoglobinopathy or bone marrow fibrosis, which requires a further increase in the rHuEPO dose. By means of early detection and correction of the possible causes, the goal of increasing therapeutic efficacy can be achieved. Iron overload may lead to an enhanced risk for infection, cardiovascular complication, and cancer. Over-treatment with iron should be avoided in dialysis patients, despite the fact that the safe upper limit of serum ferritin to avoid iron overload is not clearly defined. On the other hand, functional iron deficiency may develop even when serum ferritin levels are increased. Controversy remains as to whether intravenous iron therapy can overcome this form of hyporesponsiveness in iron-overloaded patients. Moreover, a treatment option of iron supplementation is not warranted in these patients, as the potential hazards of iron overload will be worsened. We demonstrated that the mean hematocrit significantly increased from 25.1+/-0.9% to 31+/-1.2% after eight weeks of intravenous ascorbate therapy (300 mg three times a week) in 12 hemodialysis patients with serum ferritin levels of more than 500 microg/liter. The enhanced erythropoiesis paralleled with a rise in transferrin saturation (27.8+/-2.5% vs. 44.8+/-9.5%, P < 0.05) and reductions in erythrocyte zinc protoporphyrin (130+/-32 vs. 72+/-19 micromol/mol heme, P < 0.05) and monthly rHuEPO dose (24.2+/-4.5 vs. 16.8+/-3.4 x 10(3) units, P < 0.05) at the end of study. It is speculated that ascorbate supplementation not only facilitates the iron release from storage sites and its delivery to hematopoietic tissues, but also increases iron utilization in erythroid cells. Our study provides a more complete understanding of the pathogenesis of iron overload-related anemia and the development of an adjuvant therapy, intravenous ascorbic acid, to the existing treatments.

The role of Tec protein-tyrosine kinase in T cell signaling

The Tec protein-tyrosine kinase family includes Btk, Itk/Tsk/Emt, Tec, Rlk/Txk, and Bmx which are involved in signals mediated by various cytokines or antigen receptors. Itk is expressed primarily in T cells and activated by TCR/CD3, CD28, and CD2. However, the defect in T cell signaling in itk-deficient mice is very modest. Thus, we looked for other Tec family kinases that could be expressed in lymphoid cells and involved in T cell signal transduction. Here, we demonstrate that Tec, expressed in T cells, is activated following TCR/CD3 or CD28 ligation and interacts with CD28 receptor in an activation-dependent manner. This interaction involves the Tec SH3 domain and the proline-rich motifs in CD28. We also show that Tec can phosphorylate p62(dok), one CD28-specific substrate, whereas Itk cannot. Overexpression of Tec but not Itk can enhance the interleukin-2 promoter activity mediated by TCR/CD3 or CD28 stimulation and introduction of a kinase-dead Tec but not Itk can suppress interleukin-2 expression, indicating that Tec is directly involved in T cell activation. Altogether, these data demonstrate that Tec kinase is an integral component of T cell signaling and that the two Tec family kinases, Tec and Itk, have distinct roles in T cell activation.

Apoptosis and cell proliferation in esophageal precancerous and cancerous lesions: study of a high-risk population in northern China

Changes in cell proliferation and cell death might be key factors in regulating the rate of neoplasm progression and tumor growth. The extent of apoptosis and its possible relationship with cell proliferation at different stages of esophageal carcinogenesis, however, have not been characterized. In this study, 241 esophageal biopsy samples from symptom-free subjects and 38 surgically resected esophageal carcinoma tissues from a high-risk population for esophageal cancer in Henan, China, were used to analyze the changes of apoptosis and its relationship with cell proliferation as determined by proliferating cell nuclear antigen (PCNA). The apoptotic cells, identified morphologically, were located in the same proliferative compartment of hyperproliferative cell population in the esophageal epithelium. The apoptotic indices (total number of apoptotic cells and apoptotic bodies per mm2 of the tissue section) were low in the normal epithelia, and increased significantly as the lesions progressed from basal cell hyperplasia (BCH) to dysplasia (DYS) and to squamous cell carcinoma (SCC). The extent of apoptosis correlated well with the cell proliferation indices. The present findings indicate that apoptosis occurs in the early stage of esophageal carcinogenesis, and as the lesions progress, both the apoptotic index and PCNA labelled index increase, suggesting that hyperproliferative cells might be more susceptible to apoptosis.

Thyroid dysfunction and nodular goiter in hemodialysis and peritoneal dialysis patients

OBJECTIVE

To investigate the prevalence of nodular goiter and thyroid dysfunction in uremic patients undergoing hemodialysis (HD) and peritoneal dialysis.

DESIGN

Cross-sectional study.

SETTING

Single dialysis unit and outpatient clinic.

PATIENTS

The study included 221 patients [143 HD and 78 continuous ambulatory peritoneal dialysis (CAPD) patients] along with 135 consecutively selected outpatients as controls.

MAIN OUTCOME MEASURES

Ultrasonography was used to detect patients' thyroid function and nodular goiter.

RESULTS

Nodular goiter was detected in 54.8% of the uremic patients and in 21.5% of the controls. Uremic patients had higher prevalence of thyroid dysfunction, which included reduced serum concentration of total T3, total T4, and free T4, and increased serum level of TSH. Hypothyroidism was also observed more frequently in uremic patients than in the control group (5.4% vs 0.7%, p < 0.05). Nodular goiter was more frequently found in females than in males (63.5% vs 48%, p < 0.05). Moreover, the prevalence of nodular goiter increased with age (p < 0.02) in uremic patients. Hemodialysis patients had a higher frequency of reduced total T3 level (46.9% vs 29.5%, p < 0.02). However, CAPD patients had lower T4 levels (6.23+/-1.82 microg/dL vs 7.15+/-1.99 microg/dL, p < 0.05).

CONCLUSION

Because of the high incidence of hypothyroidism and nodular goiter in uremic patients, screening of thyroid function and goiter detection with ultrasound should be considered in evaluation of end-stage renal disease patients.