Secondary wastewater disposal for crop irrigation with minimal risks

A critical objective for any wastewater reuse program is to close the gap between supply of and demand for water and to minimize health and environmental hazards. Thus, the effects of treated effluent on crops, soils and community health must be considered carefully. When applying wastewater to soil-plant systems, it is to be noted that the passage of water through the soil reduces considerably the number of microorganisms carried out by the reclaimed wastewater. Nevertheless, there is a need to study the real rate of organism decay subject to water quality, soil and vegetable characteristics, and irrigation method. The aim of this work is to determine the fate of the fecal coliforms, coliphages F+ and CN13, and helminth eggs survival during the application of reclaimed wastewater in a vineyard orchard near the City of Arad (Israel) via onsurface and subsurface drip irrigation systems. Wastewater obtained from a stabilization pond, and soil samples were tested and an important decrease of microorganisms was reached in both cases, with the better values obtained with the sub-surface drip irrigation system.

Thyroid hormone metabolism and cardiac gene expression after acute myocardial infarction in the rat

In a rat model of acute myocardial infarction (MI) produced by coronary artery ligation, thyroid hormone metabolism was altered with significant reductions (54%) in serum triiodo-L-thyronine (T(3)), the cellular active hormone metabolite. T(3) has profound effects on the heart; therefore, rats were treated with T(3) after acute MI for 2 or 3 wk, at either replacement or elevated doses, to determine whether cardiac function and gene expression could be normalized. Acute MI resulted in a 50% (P < 0.001) decrease in percent ejection fraction (%EF) with a 32-35% increase (P < 0.01) in compensatory left ventricle (LV) hypertrophy. Treatment of the MI animals with either replacement or elevated doses of T(3) significantly increased %EF to 64 and 73% of control, respectively. Expression levels of several T(3)-responsive genes were altered in the hypertrophied LV after MI, including significant decreases in alpha-myosin heavy chain (MHC), sarcoplasmic reticulum calcium-activated ATPase (SERCA2), and Kv1.5 mRNA, whereas beta-MHC and phospholamban (PLB) mRNA were significantly increased. Normalization of serum T(3) did not restore expression of all T(3)-regulated genes, indicating altered T(3) responsiveness in the postinfarcted myocardium. Although beta-MHC and Kv1.5 mRNA content was returned to control levels, alpha-MHC and SERCA2 were unresponsive to T(3) at replacement doses, and only at higher doses of T(3) was alpha-MHC mRNA returned to control values. The present study showed that acute MI in the rat was associated with a fall in serum T(3) levels, LV dysfunction, and altered expression of T(3)-responsive genes and that T(3) treatment significantly improved cardiac function, with normalization of some, but not all, of the changes in gene expression.

Thyroid hormone stimulates Na, K-ATPase gene expression in the hemodynamically unloaded heterotopically transplanted rat heart

Regulation of myocardial Na, K-ATPase gene expression by thyroid hormone was investigated in the heterotopically transplanted rat heart to distinguish the direct effects of the hormone on the heart from effects secondary to increased hemodynamic workload. In this model, the transplanted heart is histologically normal and spontaneously beating, but hemodynamically unloaded. Three days after transplantation, relative contents of ventricular Na, K-ATPase alpha2- and beta1-mRNAs and alpha1- and alpha2-proteins were increased twofold to threefold in the transplanted heart, but these changes were transient. We next determined the maximal triiodothyronine (T3)-induced changes that are observed in various parameters of Na, K-ATPase expression in the heart: treatment of nontransplanted euthyroid rats with T3 to reach hyperthyroid steady state resulted in significant increases in heart weight, RNA and RNA/protein ratio, Na, K-ATPase activity, Na, K-ATPase alpha2-protein and enzyme activity, and approximately threefold increase in both alpha2- and beta1-mRNA content. The effect of treatment with thyroxine (T4) on the heterotopically transplanted and the in situ heart was then examined. T4 treatment (of the host) resulted in a significant increase in Na, K-ATPase alpha1-, alpha2-, and beta1-mRNAs in transplanted hearts (1.6 +/- 0.1-, 2.4 +/- 0.2-, and 1.7 +/- 0.1-fold, respectively), that was associated with a 2.2 +/- 0.2-fold increase in alpha2 protein as compared to transplanted hearts in diluent-treated euthyroid hosts (p < 0.05 for all changes). In addition, T4-induced increments in transplanted hearts were similar to those observed in the corresponding in situ hearts of host rats treated with T4. We conclude that the increase in Na, K-ATPase expression by thyroid hormone largely occurs independently of increased cardiac work elicited by the hormone and reflects a direct action of the hormone on Na, K-ATPase gene expression.

Effect of cigarette smoke on salivary proteins and enzyme activities

Exposure of human plasma in vitro to gas-phase cigarette smoke (CS) causes a marked modification of plasma proteins as measured by protein carbonyl assay. Aldehydes present in CS may cause this elevation of protein carbonyls by reacting with sulfhydryl groups of proteins. Saliva is the first body fluid to confront the inhaled CS. Thus, in vitro exposure of saliva to nine "puffs" of CS also showed a distinct increase in protein carbonyls. Ascorbate and desferrioxamine mesylate had little effect on protein carbonyl formation, while GSH and N-acetylcysteine considerably inhibited the accumulation of protein carbonyls due to CS exposure. Following the exposure to CS, the activities of several salivary enzymes-amylase, lactic dehydrogenase (LDH), and acid phosphatase-were found to be significantly reduced (34, 57, and 77%, respectively). However, CS had no effect on the activities of aspartate aminotransferase and alkaline phosphatase. Addition of 1 mM of GSH and N-acetylcysteine considerably protected LDH and amylase activities, suggesting that sulfhydryl groups are affected in LDH and amylase. On the other hand, addition of 1 mM ascorbate caused a further loss of LDH and amylase activities, which could be partially prevented by the addition of desferrioxamine mesylate, implicating metal-catalyzed oxidation processes. Finally, loss of acid phosphatase activity was completely unaffected by any of the above antioxidants. It is concluded that the loss of salivary enzyme activities may be due to various agents in the CS that affect the enzyme activities via different mechanisms.

Thyroid hormone regulation of phospholamban phosphorylation in the rat heart

Thyroid hormone exerts predictable effects on the contractile performance of the heart in part by regulating the transcription of genes encoding specific calcium transporter proteins. In a rat model of hypothyroidism, left ventricular (LV) contractile function as measured by ejection fraction was decreased by 22% (P < 0.05), and this was returned to control values with T3 treatment. In confirmation of prior studies, LV phospholamban (PLB) protein content was significantly decreased by 25% and 40% compared with hypothyroid LV when the animals were treated with T3 at two doses, 2.5 and 7.0 microg/day, respectively. The ratio of sarcoplasmic reticulum calcium adenosine triphosphatase (SERCA2) to PLB protein content was thus increased by 171% and 207%, respectively (P < 0.01). Resolution of the phosphorylated PLB pentamers by SDS-PAGE showed that T3 infusion at 2.5 and 7.0 microg/day decreased (P < 0.001) the amount nonphosphorylated pentamers by 82% and 95%, respectively, in a dose-dependent manner. T3 treatment produced an increase in the proportion of highly phosphorylated PLB pentamers (more than five phosphates) when expressed as a fraction of total pentameric molecules (P < 0.05). Site-specific antibodies showed that the T3-induced increase in phosphorylated PLB pentamers was the result of an increase in both serine 16 and threonine 17 phosphorylation. We conclude that thyroid hormone, in addition to regulating the expression of cardiac PLB, is able to alter the degree of PLB phosphorylation, which correlates with enhancement of LV contractile function. These studies suggest that T3 may augment myocyte calcium cycling via changes in both cAMP- and calcium/calmodulin-dependent protein kinase activities.

Changes in adenylyl cyclase isoforms as a mechanism for thyroid hormone modulation of cardiac beta-adrenergic receptor responsiveness

Although thyroid hormones are known to modulate cardiac beta-adrenergic receptor expression, the physiologic implications of these changes in the cardiac manifestations of altered thyroid hormone metabolism have been disputed. This study examined whether thyroid hormone modulates signaling via the cyclic adenosine monophosphate (cAMP) pathway by regulating cardiac adenylyl cyclase (AC) isoform expression. Northern blot analyses and AC enzyme assays were performed on preparations from hypothyroid, euthyroid, and hyperthyroid rat ventricles. Steady-state levels of cardiac AC mRNA types V and VI in hypothyroid ventricles were 173% +/- 8% and 149% +/- 12%, respectively, of the values in euthyroid ventricles (P < .01). This increase in AC mRNA isoforms was accompanied by a 1.5-fold increase (P < .05) in the activation of catalytic AC by forskolin and Mn. In contrast, the relative abundance of transcripts for types V and VI AC was similar in hyperthyroid and euthyroid ventricles, but catalytic AC activation by forskolin and Mn was significantly reduced by 35% in membranes obtained from hyperthyroid ventricles. AC activation through beta-adrenergic receptor stimulation by isoproterenol was not altered by thyroid hormone status. Thus, the effect of thyroid hormone to repress AC catalytic activity would be anticipated to offset the increase in beta-adrenergic receptor expression in hyperthyroidism. These studies identify cardiac AC enzymes as important targets for thyroid hormone-dependent regulation of signaling via the cAMP pathway, and support the finding that cardiac adrenergic responsiveness is unaltered in thyroid disease states.

Effects of thyroid hormone on action potential and repolarizing currents in rat ventricular myocytes

Thyroid hormones play an important role in cardiac electrophysiology through both genomic and nongenomic mechanisms of action. The effects of triiodothyronine (T(3)) on the electrophysiological properties of ventricular myocytes isolated from euthyroid and hypothyroid rats were studied using whole cell patch clamp techniques. Hypothyroid ventricular myocytes showed significantly prolonged action potential duration (APD(90)) compared with euthyroid myocytes, APD(90) of 151 +/- 5 vs. 51 +/- 8 ms, respectively. Treatment of hypothyroid ventricular myocytes with T(3) (0.1 microM) for 5 min significantly shortened APD by 24% to 115 +/- 10 ms. T(3) similarly shortened APD in euthyroid ventricular myocytes, but only in the presence of 4-aminopyridine (4-AP), an inhibitor of the transient outward current (I(to)), which prolonged the APD by threefold. Transient outward current (I(to)) was not affected by the acute application of T(3) to either euthyroid or hypothyroid myocytes; however, I(to) density was significantly reduced in hypothyroid compared with euthyroid ventricular myocytes.

An inventory of the human ABC proteins

Currently 30 human ABC proteins are represented by full sequences in various databases, and this paper provides a brief overview of these proteins. ABC proteins are composed of transmembrane domains (TMDs), and nucleotide binding domains (NBDs, or ATP-binding cassettes, ABSs). The arrangement of these domains, together with available membrane topology models of the family members, are presented. Based on their sequence similarity scores, the members of the human ABC protein family can be grouped into eight subfamilies. At present the MDR/TAP, the ALD, the MRP/CFTR, the ABC1, the White, the RNAseL inhibitor, the ANSA, and the GCN20 subfamilies are identified. Mutations of many human ABC proteins are known to be causative in inherited diseases, and a short description of the molecular pathology of these ABC gene-related genetic diseases is also provided.

[Molecular genetic study of medullary thyroid cancer]

Around 25% of medullary thyroid carcinoma (MTC) cases are familial and follow an autosomal dominant mode of inheritance. In these cases, MTC is part of an inherited cancer syndrome that has three distinct forms: MEN2A, MEN2B and familial MTC (FMTC). MEN2A is the most frequent syndrome, followed by FMTC and MEN2B. In 95% of MEN2A families and 85% of FMTC families, the germ-line missense mutations underlying the disease affect one of the five cysteine codons of the extracellular domain of the RET proto-oncogene. The mutated codons are 609, 611, 618 and 620 in exon 10, and 634 in exon 11. The most frequent mutations (80% in MEN2A, and 50% in FMTC) occur in codon 634. In our laboratory, the mutations of the codon 634 was detected by two independent methods: DNA sequencing and restriction fragment length polymorphism with polymerase chain reaction (PCR-RFLP). We have so far examined 105 persons at risk and found 19 positive cases. A positive genetic diagnosis allows preventive thyroidectomy, with a resultant cause-specific survival similar to that for the general population. In the event of a negative result, the family members of the affected proband are relieved of the physical and emotional consequences of the disease and the follow-up procedures. We plan to screen all 240 known Hungarian MTC patients and their relatives.

[A new method of molecular testing in the differential diagnosis of hereditary hemochromatosis]

Hereditary hemochromatosis is an autosomal, recessive disorder of the iron metabolism. The hemochromatosis gene (HFE) was previously located on chromosome 6 and recently identified by positional cloning. A point mutation, C282Y, was found to be present in the HFE gene in homozygous form in 64 to 100% of patients with established hemochromatosis. The relationship of a second polymorphic variant of the HFE gene, H63D to the formation of iron overload is debated. Although hemochromatosis is one of the most common inherited disorders among Caucasians, in the absence of specific signs it is rarely diagnosed. In order to obtain comparable epidemiological data for Hungary, we tested 1271 and 277 randomly selected, unrelated, healthy subjects for C282Y and H63D respectively. In addition C282Y testing was carried out in 58 patients suffering from liver cirrhosis, and in 191 individuals with suspected hemochromatosis. For C282Y and H63D mutation analyses polymerase chain reaction technique followed by Rsa I and Bcl I restriction enzyme digestion was used. We developed an alternative method for the detection of C282Y based on an amplification-generated Kpn I restriction site. The allele frequencies were 3.8% and 12.3% for C282Y and H63D respectively in the normal Hungarian population. There was no significant difference in C282Y allele frequencies between liver disease patients (1.7%) and the normal population. We identified 15 homozygous and 25 heterozygous individuals among 191 individuals with suspected hemochromatosis. The C282Y and the H63D allele frequencies in the normal Hungarian population were found to be similar to the allele frequencies observed in other European populations, indicating that there is a large number of individuals susceptible for iron overload in Hungary (1:700). Mutation analysis is a novel, non-invasive method in the diagnostics of hereditary hemochromatosis, which increasingly becomes part of the routine clinical work.

Usefulness of triiodothyronine (T3) treatment after surgery for complex congenital heart disease in infants and children

This is a study of the use of T3 infusion in the postoperative period in 6 pediatric patients who underwent complex cardiac surgical procedures under cardiopulmonary bypass. Normalization of serum T3 levels was reflected in a marked decrease in requirement of inotropic support, conversion to normal sinus rhythm, and progressively improving clinical course.

Regulation of rat cardiac Kv1.5 gene expression by thyroid hormone is rapid and chamber specific

Thyroid hormone affects the contractile and electrophysiological properties of the cardiac myocyte that result in part from changes in the expression of thyroid hormone-responsive cardiac genes, including those that regulate membrane ion currents. To determine the molecular mechanisms underlying this effect, expression of a voltage-gated K+ channel, Kv1.5, was measured in response to thyroid hormone. Using quantitative RT-PCR methodology, the content of Kv1.5 messenger RNA (mRNA) in left ventricles of euthyroid rats was 4.25+/-0.6x10(-20) mol/microg total RNA and was decreased by 70% in the hypothyroid rat ventricle to 1.27+/-0.80x10(-20) mol/microg RNA (P<0.01). Administration of T3 to hypothyroid animals restored ventricular Kv1.5 mRNA to control levels within 1 h of treatment, making this the most rapid T3-responsive cardiac gene reported to date. The half-life of Kv1.5 mRNA was 1.9 h and 2.0 h in euthyroid and hypothyroid ventricles, respectively, and T3 treatment of the rats did not alter its half-life. In atrial myocardium, expression of Kv1.5 mRNA (6.10+/-0.37x10(-20) mol/microg RNA) was unaltered by thyroid hormone status. The myocyte-specific and chamber-selective expression of Kv1.5 mRNA was confirmed in primary cultures of rat atrial and ventricular myocytes.

Regulation of Na/K-ATPase gene expression by thyroid hormone and hyperkalemia in the heart

Hypothermic hyperkalemic circulatory arrest has been widely used for myocardial protection during heart surgery. Recent data showed that administration of triiodo-L-thyronine (T3) postoperatively enhanced ventricular function. The effect of hyperkalemic arrest in conjunction with thyroid hormone on the plasma membrane enzyme sodium/potassium-adenosine triphosphatase (Na/K-ATPase), was determined in cultured neonatal rat atrial and ventricular myocytes. Exposure of ventricular myocytes to hyperkalemic medium (50 mM KCl) in the absence of T3 increased expression of the Na/K-ATPase catalytic subunit mRNAs, alpha1 and alpha3 isoforms, by 1.9- and 1.5-fold, respectively (p<0.01), which were accompanied by similar increases (1.4- and 1.8-fold) in protein content. Addition of T3 to the hyperkalemic cultures attenuated these increases in Na/K-ATPase mRNA isoforms to levels of expression observed in cells treated with T3 (10(-8) M) alone. Similarly, expression of the alpha1 mRNA isoform in atrial myocytes was increased (p<0.05) by hyperkalemic conditions, and T3 treatment attenuated this effect. In contrast, although expression of the Na/K-ATPase beta1 mRNA in both atrial and ventricular myocytes was significantly increased by hyperkalemia, addition of T3 did not prevent the hyperkalemic response, and in atrial myocytes T3 significantly increased beta1 mRNA expression 1.8-fold. These results show that expression of cardiac Na/K-ATPase is regulated by T3 and hyperkalemia in an isoform and chamber specific manner, and suggest that use of hyperkalemic cardioplegia during heart surgery may alter plasma membrane ion function.

Outcome after treatment of high-risk papillary and non-Hürthle-cell follicular thyroid carcinoma

BACKGROUND

Treatment of differentiated thyroid cancer has been studied for many years, but the benefits of extensive initial thyroid surgery and the addition of radioiodine therapy or external radiation therapy remain controversial.

OBJECTIVE

To determine the relations among extent of surgery, radioiodine therapy, and external radiation therapy in the treatment of high-risk papillary and non-Hürthle-cell follicular thyroid carcinoma.

DESIGN

Analysis of data from a multicenter study.

SETTING

14 institutions in the United States and Canada participating in the National Thyroid Cancer Treatment Cooperative Study Registry.

PATIENT

385 patients with high-risk thyroid cancer (303 with papillary carcinoma and 82 with follicular carcinoma).

MEASUREMENTS

Death, disease progression, and disease-free survival.

RESULTS

Total or near-total thyroidectomy was done in 85.3% of patients with papillary carcinoma and 71.3% of patients with follicular cancer. Overall surgical complication rate was 14.3%. Total or near-total thyroidectomy improved overall survival (risk ratio [RR], 0.37 [95% CI, 0.18 to 0.75]) but not cancer-specific mortality, progression, or disease-free survival in patients with papillary cancer. No effect of extent of surgery was seen in patients with follicular thyroid cancer. Postoperative iodine-131 was given to 85.4% of patients with papillary cancer and 79.3% of patients with follicular cancer. In patients with papillary cancer, radioiodine therapy was associated with improvement in cancer-specific mortality (RR, 0.30 [CI, 0.09 to 0.93 by multivariate analysis only]) and progression (RR, 0.30 [CI, 0.13 to 0.72]). When tall-cell variants were excluded, the effect on outcome was not significant. After radioiodine therapy, patients with follicular thyroid cancer had improvement in overall mortality (RR, 0.17 [CI, 0.06 to 0.47]), cancer-specific mortality (RR, 0.12 [CI, 0.04 to 0.42]), progression (RR, 0.21 [CI, 0.08 to 0.56]), and disease-free survival (RR, 0.29 [CI, 0.08 to 1.01]). External radiation therapy to the neck was given to 18.5% of patients and was not associated with improved survival, lack of progression, or disease-free survival.

CONCLUSIONS

This study supports improvement in overall and cancer-specific mortality among patients with papillary and follicular thyroid cancer after postoperative iodine-131 therapy. Radioiodine therapy was also associated with improvement in progression in patients with papillary cancer and improvement in progression and disease-free survival in patients with follicular carcinoma.

High frequency of the haemochromatosis C282Y mutation in Hungary could argue against a Celtic origin of the mutation

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Thyrotropin suppression and disease progression in patients with differentiated thyroid cancer: results from the National Thyroid Cancer Treatment Cooperative Registry

The ideal therapy for differentiated thyroid cancer is uncertain. Although thyroid hormone treatment is pivotal, the degree of thyrotropin (TSH) suppression that is required to prevent recurrences has not been studied in detail. We have examined the relation of TSH suppression to baseline disease characteristics and to the likelihood of disease progression in a cohort of thyroid cancer patients who have been followed in a multicenter thyroid cancer registry that was established in 1986. The present study describes 617 patients with papillary and 66 patients with follicular thyroid cancer followed annually for a median of 4.5 years (range 1-8.6 years). Cancer staging was assessed using a staging scheme developed and validated by the registry. Cancer status was defined as no residual disease; progressive disease at any follow-up time; or death from thyroid cancer. A mean TSH score was calculated for each patient by averaging all available TSH determinations, where 1 = undetectable TSH; 2 = subnormal TSH; 3 = normal TSH; and 4 = elevated TSH. Patients were also grouped by their TSH scores: group 1: mean TSH score 1.0-1.99; group 2: mean TSH score 2.0-2.99; group 3: mean TSH score 3.0-4.0. The degree of TSH suppression did not differ between papillary and follicular thyroid cancer patients. However, TSH suppression was greater in papillary cancer patients who were initially classified as being at higher risk for recurrence. This was not the case for follicular cancer patients, where TSH suppression was similar for all patients. For all stages of papillary cancer, a Cox proportional hazards model showed that disease stage, patient age, and radioiodine therapy all predicted disease progression, but TSH score category did not. However, TSH score category was an independent predictor of disease progression in high risk patients (p = 0.03), but was no longer significant when radioiodine therapy was included in the model (p = 0.09). There were too few patients with follicular cancer for multivariate analysis. These data suggest that physicians use greater degrees of TSH suppression in higher risk papillary cancer patients. Our data do not support the concept that greater degrees of TSH suppression are required to prevent disease progression in low-risk patients, but this possibility remains in high-risk patients. Additional studies with more patients and longer follow-up may provide the answer to this important question.

Prospective multicenter study of thyroiscarcinoma treatment: initial analysis of staging and outcome. National Thyroid Cancer Treatment Cooperative Study Registry Group

BACKGROUND

A novel prognostic staging classification encompassing all forms of thyroid carcinoma was created for the National Thyroid Cancer Treatment Cooperative Study (NTCTCS) Registry, with the goal of prospective validation and comparison with other available staging classifications.

METHODS

Patient information was recorded prospectively from 14 institutions. Clinicopathologic staging was based on patient age at diagnosis, tumor histology, tumor size, intrathyroidal multifocality, extraglandular invasion, metastases, and tumor differentiation.

RESULTS

Between 1987 and 1995, 1607 patients were registered. Approximately 43% of patients were classified as NTCTCS Stage I, 24% Stage II, 24% Stage III, and 9% Stage IV. Patients with follicular carcinoma were more likely to have "high risk" Stage III or IV disease than those with papillary carcinoma. Of 1562 patients for whom censored follow-up was available (median follow-up, 40 months), 78 died of thyroid carcinoma or complications of its treatment. Five-year product-limit patient disease specific survival was 99.8% for Stage I, 100% for Stage II, 91.9% for Stage III, and 48.9% for Stage IV (P < 0.0001). The frequency of remaining disease free also declined significantly with increasing stage (94.3% for Stage I, 93.1%for Stage II, 77.8% for Stage III, and 24.6% for Stage IV). The same patients also were staged applying six previously published classifications as appropriate for their tumor type. The predictive value of the NTCTCS Registry staging classification consistently was among the highest for disease specific mortality and for remaining disease free, regardless of the tumor type.

CONCLUSIONS

The NTCTCS Registry staging classification provides a prospectively validated scheme for predicting short term prognosis for patients with thyroid carcinoma.