Influence of the sample collection method on salivary interleukin–6 levels in resting and post-exercise conditions

Previous studies demonstrated that no significant relationships exist between salivary and serum IL-6 in resting conditions and following exercise and that appropriate saliva collection procedures allow to avoid analytical drawbacks. This investigation aimed to: (a) compare the effects of two methods of saliva collection on IL-6 assay; (b) search for correlation between salivary and serum IL-6 in resting and post-exercise conditions; (c) evaluate the IL-6 response to isometric contractions. Seventeen sedentary subjects and fifteen athletes underwent one blood and two salivary draws: saliva was collected chewing on cotton salivettes and using a plastic straw (SA method and ST method, respectively). Afterwards, the athletes only completed a fatiguing isometric exercise of the knee extensors and blood and saliva were sampled after the exercise. In the entire group (n=32), ST method produced higher IL-6 levels than SA method and serum sampling. The exercise elicited significant responses of lactate, serum IL-6, salivary IL-6 (by ST method): salivary IL-6 values using the ST collection method were higher at each sampling point than with the SA method. The correlation analyses applied to both resting levels in the entire group and absolute changes above baseline in the athlete group showed that: (1) no significant relationships exist between serum and salivary IL-6 levels; (2) the greater the salivary IL-6 measurement, the higher the resultant inaccuracy of the SA method; (3) significant correlations exist between isometric force and mechanical fatigue during exercise and peaks of lactate and serum IL-6. These data provided demonstration of a cotton-interference effect for the results of salivary IL-6 assay and confirmed the lack of significant correlation between salivary and serum IL-6 in resting and post-exercise conditions.

Efficacy and sensitivity of axial scans and different reconstruction methods in the study of the ulcerated carotid plaque using multidetector-row CT angiography: comparison with surgical results

BACKGROUND AND PURPOSE

Carotid plaque ulceration is an important risk factor for stroke, and its diagnosis may be very important to plan a correct therapeutic approach. We hypothesized that axial scans and various reconstruction methods could have different specificity and sensitivity in the study of plaque ulceration. The object of this study was to evaluate their role and diagnostic efficacy in patients with carotid plaque complicated by ulceration through the comparison with surgical results.

MATERIALS AND METHODS

From January 2004 to November 2005, 109 patients who underwent a carotid endarterectomy were analyzed using CT angiography for a total of 218 carotid arteries. We assessed every carotid for the presence of ulcerations. For each patient axial image, maximum intensity projection (MIP), multiplanar reconstruction (MPR), shaded surface display (SSD), and volume rendering (VR) reconstructions were obtained.

RESULTS

Multidetector row CT angiography (MDCT) found 32 ulcerations; surgical confirmation underlined an overall 93.9% sensitivity (95% confidence interval [CI] 0.858-1.021), and a 98.7% specificity (95% CI, 0.961-1.012). Axial scans and volume rendering images demonstrated the highest sensitivity (90.9% and 87.9%, respectively); SSD, on the contrary, showed the lowest sensitivity: 39.4% (95% CI sensitivity, 0.227-0.561).

CONCLUSION

Axial scans plus VR reconstruction techniques offer superior depiction of carotid plaque ulceration compared with MIP, MPR, and SSD.

Spiral computed tomography imaging of bowel ischemia: a literature review

The aim of this study was to evaluate the reported diagnostic efficacy of multidetector-row computed tomography (MDCT) for bowel ischemia and to identify the radiological signs that permit diagnosis. Based on a review of the literature, spiral CT sensitivity and specificity data were compared, as was the impact of last-generation CT scanner technology on the diagnosis of bowel ischemia. The data source was the PubMed database, from which 106 articles published in English from January 1998 to January 2006 were selected: 18 studies met the inclusion criteria. MDCT was reported to be more sensitive than CT for diagnosing bowel ischemia. The most frequent signs of disease were bowel wall thickening, intramural pneumatosis, mesenteric or portal venous gas, and mesenteric arterial or venous thromboembolism. The results of the literature review suggest that MDCT has high sensitivity for detecting bowel ischemia. Moreover, the use of MDCT angiography to evaluate abdominal vessels offers a better definition of vascular mapping and of the complications of bowel disease.

[Portosystemic shunt encephalopathy. Clinical and radiological evaluation by using multidetector-row CT angiography]

We describe the case of a 72-year-old woman who presented a symptomatology characterized by recurrent episodes of confusion, weakness with cerebral vasculopathy. The high values of ammonium were correctly defined thanks to the diagnostic multidetector-row CT information and we referred the symptoms to porto-systemic shunts with the exclusion of hepatic vascularization due to an inferior vena cava stenosis.

Interleukin-6 response to isokinetic exercise in elite athletes: relationships to adrenocortical function and to mechanical and myoelectric fatigue

Exercise stimulates the release of interleukin-6 (IL-6). Aims of the study were to: (a) analyse the IL-6 response to exercise in power (n = 7) and endurance athletes (n = 13); (b) determine the effects of the IL-6 production on mechanical and myoelectric fatigue; (c) evaluate the relationship between IL-6 and adrenocortical responses. EMG variables (conduction velocity, mean power frequency, average rectified value), ACTH, cortisol, DHEA, IL-6, myoglobin, and lactate were analysed before and after an isokinetic exercise. The exercise elicited significant mechanical and myoelectric fatigue as well as significant biochemical responses. Power athletes showed IL-6 and lactate responses higher than endurance athletes. The correlation analyses showed that the greater the mechanical fatigue, the greater the increases in lactate and IL-6. No correlations were found between IL-6 and EMG variables. No relationships were found between IL-6 and cortisol, after correction for ACTH levels. In conclusion, the muscular IL-6 production, as inferred by its circulating levels, had no detectable effects on the myoelectric manifestations of fatigue and the cortisol response to exercise was not related to the amount of circulating IL-6, but only to the activation of ACTH secretion.

Serum interleukin-6 response to elective total hip replacement surgery

The focus of this work was to study the serum interleukin-6 (IL-6) response to total hip replacement. Twenty-one patients received an uncemented total hip prosthesis. Venous samples for IL-6 determination were drawn before and after surgery. The IL-6 response was significant, and a peculiar heterogeneity of response was apparent: the medians of peak levels (82.3 pg/ml) and of areas under the response curve (51.8 pg/ml) distinguished between IL-6 high responders (HR) and IL-6 low responders (LR; p<0.0001). No difference was found in the gender composition of these groups, whereas the HR patients were older than the LR patients (p<0.05). The amount of IL-6 increase was found to correlate with patient age, whereas its slope was found to correlate with the duration of the surgical procedure. Moreover, the HR group presented a higher degree of hyperthermia in the days after surgery compared with the LR patients, without evidence of differences in postoperative complications, time to mobilisation, or length of stay in hospital. The main finding of our study was the evidence of a remarkable variability between individuals in the IL-6 response to surgery. Future studies are needed to identify the factors involved in the regulation of the cytokine response to surgery.

Differential responses of serum and salivary interleukin-6 to acute strenuous exercise

Physical exercise is associated with elevation of serum levels of interleukin-6 (IL-6) because of its production in the muscles. The use of IL-6 measurements in saliva has been proposed in the field of immunopathology, mainly involving salivary gland disease. We evaluated the responses of serum and salivary IL-6 in two different groups of athletes submitted to different types of controlled strenuous exercise (spinning activity and maximal isokinetic test). Serum and salivary samples for IL-6 measurements, and serum samples for lactate and myoglobin determination before and after exercise, were obtained. Salivary IL-6 was measured by ELISA after dilution experiments and compared with results obtained by immunoradiometric assay. Spinning activity elicited significant increases in all the variables, and no correlation was found among the respective variations. A significant response to the isokinetic exercise was observed for serum IL-6, lactate and myoglobin only; no correlation was found between serum and salivary IL-6. Our study demonstrated that serum and salivary IL-6 responses to exercise are dissociated, possibly in relation to the lack of relationships between the systemic/muscular and the salivary routes of IL-6 production. Analytical issues that concern IL-6 measurement in saliva deserve attention, notably regarding the collection method used to absorb saliva. Concomitant monitoring of serum markers of inflammation, muscle metabolism and damage can provide information about muscle function properties and adaptations to physical effort in different types of athletes.

Natural killer cell activity and sensitivity to positive and negative modulation in uncomplicated obese subjects: relationships to leptin and diet composition

BACKGROUND

Natural killer (NK) cells are a key component of innate immunity; their activity is modulated by cytokines and hormones and is influenced by diet. In obesity, a higher risk of cancer and infections has been demonstrated. Studies on NK cell activity have yielded inconsistent results; NK cell sensitivity to modulators has not been assessed before.

OBJECTIVE

In this case-control study, we assessed both spontaneous NK cell activity and responsiveness to positive (interleukin (IL)-2) and negative (cortisol) modulators in uncomplicated obesity; we searched for correlations between NK cell activity and anthropometric, dietary and metabolic variables.

METHODS

In all, 21 obese (six males/15 females) and 21 age- and sex-matched healthy nonobese subjects underwent clinical examination and dietary and laboratory analyses. Spontaneous and modulated NK activities of peripheral blood mononuclear cells were measured by enzyme-release cytotoxicity assay.

RESULTS

Spontaneous NK cell activity was not different in obese subjects vs controls. IL-2 stimulated and cortisol inhibited NK cell activity in both populations. Cortisol-dependent inhibition was lower in the obese than in the control group (-24.4+/-2.9 vs -38.6+/-3.3%, P=0.002), but decreased sensitivity was restricted to women (P=0.0007). In obese subjects, cortisol-dependent inhibition negatively correlated with serum leptin levels (r=-0.54, P=0.02) and, in women, with body mass index (r=-0.63, P=0.01); IL-2-dependent stimulation positively correlated with dietary carbohydrates (r=0.61, P=0.005) and serum LDL levels (r=0.55, P=0.009) and negatively correlated with dietary lipids (r=-0.71, P=0.0006).

CONCLUSION

Spontaneous and IL-2-inducible NK cell activity is normal in uncomplicated obesity. Sensitivity to IL-2 correlates with fat and carbohydrate intake. Sensitivity to glucocorticoids negatively correlates with serum leptin levels and is significantly diminished in obese women, in whom it correlates with body mass index.

The R100Q mutation of the GABA(A) alpha(6) receptor subunit may contribute to voluntary aversion to ethanol in the sNP rat line

We have investigated the GABA(A) alpha(6) subunit molecular composition in two rat lines selectively bred for high or low ethanol preference and consumption, namely Sardinian alcohol-preferring (sP) and Sardinian non-alcohol-preferring (sNP) rats, which have been bred at the University of Cagliari, Italy, since 1981. A total of 27 sP, 22 sNP and 25 control rats belonging to five other different strains, were studied by direct sequencing and amplification refractory mutation system analysis. Among the sNPs, only one was found to be normal, 11 heterozygotes, and 10 homozygotes for the G-->A substitution in codon 100, the same R100Q point mutation previously described in Alcohol Non Tolerant rats, while no other animal showed any mutated allele. Pharmacological studies have extensively demonstrated that this substitution in the mature peptide changes the benzodiazepine-insensitive receptor to a sensitive one. In order to test the functional significance of this mutation in native cerebellar GABA(A) receptors, selective breeding from Q/R rats was employed to obtain a sufficient number of R/R homozygotes. Xenopus laevis oocytes were then injected with cerebellar synaptosomes extracted from Q/Q, R/Q and R/R sNP rats. Consistently, utilizing the two-electrode voltage-clamp technique, GABA-evoked currents mediated by GABA(A) receptors containing the mutated alpha(6) subunit were potentiated by diazepam with about a two-fold increased potency, as compared to receptors containing the wild-type, benzodiazepine-insensitive alpha(6) subunit. Our data show for the first time that a mutated GABA(A) alpha(6) receptor subunit segregates in a rat line which voluntarily avoids alcohol consumption, and further support a possible involvement of the GABA(A) receptor containing a mutated alpha(6) subunit in the genetic predisposition to alcohol preference.

Perceptual responses in patients with inflammatory and functional bowel disease

BACKGROUND AND AIMS

Enhanced visceral sensitivity following a transient inflammatory process in the gut has been postulated as an aetiological mechanism of irritable bowel syndrome (IBS). In this study we compared perceptual responses to rectosigmoid distension in patients with mild chronic inflammation of the rectum (ulcerative colitis (UC)) and patients without mucosal inflammation (IBS) to determine if chronic low grade mucosal inflammation may be a plausible explanation for rectosigmoid hypersensitivity reported in both IBS and UC patients.

METHODS

UC disease activity was quantified using activity index scores. Perception thresholds for discomfort during rectosigmoid distension were compared between 11 UC patients with quiescent or mild disease activity, 18 IBS patients, and 13 healthy controls.

RESULTS

Although UC activity index scores negatively correlated with perceptual thresholds for discomfort (r=-0.76, p=0.016), UC patients had higher discomfort thresholds compared with IBS patients and controls before (p=0.02) and after (p<0.001) a noxious sigmoid conditioning stimulus.

CONCLUSIONS

Rectal perception was attenuated in UC but enhanced in IBS. In chronic mild inflammation, activation of antinociceptive mechanisms may prevent the development of visceral hyperalgesia. Low grade mucosal inflammation alone is unlikely to be responsible for symptoms in functional gastrointestinal disorders.

Symptoms and visceral perception in patients with pain-predominant irritable bowel syndrome

OBJECTIVE

Abdominal pain is thought to be a hallmark of the irritable bowel syndrome (IBS), although currently used symptom criteria do not differentiate between abdominal pain and discomfort. By focusing on viscerosensory symptoms, we sought to determine: 1) which type of symptoms are most commonly reported by IBS patients, and 2) whether patients who report pain as their most bothersome symptom differ in clinical, psychological, and physiological characteristics.

METHODS

A total of 443 consecutive new patient referrals to a tertiary referral center for functional gastrointestinal disorders who met symptom criteria for IBS were given validated, psychometric, health status, and bowel symptom questionnaires containing specific questions regarding the patients' predominant viscerosensory gastrointestinal symptom. Of these patients, 155 (35%) also met criteria for functional dyspepsia. A representative subset of the total IBS patient population (n = 58) underwent evaluation of perceptual responses to controlled rectal distension before and after a noxious sigmoid conditioning stimulus.

RESULTS

Viscerosensory symptoms clustered into four groups: 1) abdominal pain, 2) bloating-type discomfort, 3) sensation of incomplete rectal evacuation, and 4) extraabdominal (chest pain or pressure and nausea). A total of 66% of patients reported gas as one of their viscerosensory symptoms, whereas 60% reported abdominal pain as one of their symptoms. Only 29% rated abdominal pain as their most bothersome symptom, whereas bloating-type symptoms were listed by 60% as most bothersome. Although pain predominance did not correlate with the severity of gastrointestinal or psychological symptoms, there was a significant correlation with the development of rectal hypersensitivity in response to the sigmoid conditioning stimulus.

CONCLUSIONS

In a tertiary referral population of IBS patients: 1) abdominal pain is reported by only one third of patients as their most bothersome viscerosensory symptoms; and 2) pain-predominance correlates with development of rectal hypersensitivity after a noxious sigmoid stimulus.

Esophageal carcinoma secondary to a chemical injury in a child

Twin sisters were clinically and endoscopically followed due to chemical injuries to the esophagus after ingestion of muriatic acid at 10 months of age. One of the girls developed esophageal carcinoma 10 years later and died after esophagectomy because of progression of the disease. Her twin sister has a severe stenosis at the distal esophagus and is waiting for surgical treatment. Malignization of a chemical injury to the esophagus in a child has not yet been described in the literature, emphasizing the role of endoscopic follow-up with periodic biopsies.

Subtypes of constipation predominant irritable bowel syndrome based on rectal perception

BACKGROUND

Patients who complain of constipation can be divided into those who have lost the natural call to stool, but develop abdominal discomfort after several days without a bowel movement (no urge); and those who experience a constant sensation of incomplete evacuation (urge).

AIMS

To determine whether the two groups differ in symptoms, colonic transit, and perceptual responses to controlled rectal distension.

METHODS

Forty four patients with constipation were evaluated with a bowel symptom questionnaire, colonic transit (radiopaque markers), and rectal balloon distension. Stool (S) and discomfort (D) thresholds to slow ramp (40 ml/min) and rapid phasic distension (870 ml/min) were determined with an electronic distension device. Fifteen healthy controls were also studied.

RESULTS

All patients had Rome positive irritable bowel syndrome (IBS); 17 were no urge and 27 urge. Mean D threshold to phasic rectal distensions was 28 (3) mm Hg in no urge, 27 (3) mm Hg in urge (NS), but higher in the control group (46 (2) mm Hg; p < 0.01). Sixty seven per cent of no urge and 69% of urge were hypersensitive for D. Slow ramp distension thresholds were higher in no urge (S: 26 (3); D: 45 (4) mm Hg) compared with urge (S: 16 (2); D: 31 (3) mm Hg; p < 0.01), or with controls (S: 15 (1); D: 30 (3); p < 0.01).

CONCLUSIONS

Hyposensitivity to slow rectal distension is found in patients with IBS who complain of constipation and have lost the call to stool even though their sensitivity to phasic distension is increased.

Molecular diagnosis and carrier screening for beta thalassemia

Thalassemias are common autosomal recessive disorders especially in populations of Mediterranean, Middle Eastern, and Far Eastern descent. Relatively high incidence is also observed in people of Asian Indian origin but the incidence is more limited in those of African descent. Beta Thalassemias are heterogeneous at the molecular level, with more than 150 different molecular defects identified to date. Despite this heterogeneity, each at-risk population has its own spectrum of common mutations, usually from 5 to 10, a finding that simplifies mutation analysis. Homozygosity for beta thalassemias usually results in transfusion-dependent thalassemia major and, rarely, in mild non-transfusion-dependent conditions. Molecular diagnosis may be used to define genotypes associated with mild forms. Advances in carrier diagnosis using hematologic analysis followed by mutation analysis have made possible the population screening of women at childbearing age and prenatal diagnosis. This approach in combination with nondirective genetic counseling has resulted in a consistent decline of the birth of affected homozygotes in several Mediterranean at-risk populations, as well as knowledge of the risks of being a carrier. Molecular diagnosis of homozygotes and identification of carriers of beta thalassemia may lead to improved clinical management of patients with the disorder and prevention of the birth of affected homozygotes.

Molecular analysis of patients of Sardinian descent with Crigler-Najjar syndrome type I

This study reports the molecular characterisation of the bilirubin UDP-glucuronosyl-transferase gene (UGT1) in a group of patients of Sardinian descent with Crigler-Najjar syndrome type I and their relatives. Sequence analysis of both UGT1A exon 1 and common exons 2-5 was performed in all patients, leading to the detection of AF170 and a novel mutation (470insT), both residing in UGT1A exon 1. All but two heterozygotes for the AF170 mutation showed normal serum bilirubin levels. These two subjects were also heterozygous for the sequence variation A(TA)7TAA in the promoter region of the UGT1A gene.

Homozygous beta-thalassaemia resulting in the beta-thalassaemia carrier state phenotype

This paper describes the phenotypic manifestations of a very mild beta-thalassaemia mutation detected in several members of two families of Italian descent. The molecular defect, defined by denaturing gradient gel electrophoresis analysis and direct sequencing, consists of a C-->G substitution at position 844 of IVSII of the beta-globin gene within the consensus sequence of the IVSII acceptor splice site. Heterozygotes for this mutation show a haematological phenotype ranging in severity from silent beta-thalassaemia to that of a mild beta-thalassaemia carrier state, whereas homozygotes have the typical manifestations commonly resulting from heterozygosity for a beta-thalassaemia mutation. Compound heterozygotes for the IVSII nt844 (C-->G) mutation and a severe beta-thalassaemia mutation have the phenotype of thalassaemia intermedia. This paper indicates that the presence of borderline red blood cell indices or HbA2 values should make one suspect the presence of a very mild or silent beta-thalassaemia.

Thalassaemia in Azerbaijan

beta thalassaemia is present throughout the southern regions of the former USSR. We have defined the clinical picture of the disorder, the spectrum of beta thalassaemia mutations, and the role of customary consanguineous marriage in Azerbaijan, where thalassaemia presents a public health problem of the same order as that in Greece. Contrary to earlier suggestions, we found that the common form of the disorder is typically severe. Typical Turkish, Mediterranean, Azeri, Kurdish, and Asian Indian mutations were found, consistent with the history of the region. The common Mediterranean beta 0 thalassaemia mutation (codon 39) was not found. Three mutations (codon 8-AA, IVS2-1 and IVS1-110) account for over 80% of beta thalassaemia genes. Consanguineous marriage appears to contribute relatively little to the frequency of affected births. These observations provide the basis for a thalassaemia prevention programme in Azerbaijan.

Prenatal diagnosis of inherited hemoglobinopathies

This paper reviews the techniques presently available for the prenatal diagnosis of inherited hemoglobinopathies. At the present time, mutations of the globin genes are detected directly in trophoblast DNA, enzymatically amplified by polymerase chain reaction. Known mutations may be defined by restriction endonuclease digestion, non denaturing gradient gel electrophoresis, allele specific oligonucleotide probes or allele specific oligonucleotide primers. Unknown mutations are detected by denaturing gradient gel electrophoresis followed by direct sequencing. Other potentially useful methods for unknown mutations are single strand conformation polymorphism analysis and chemical mismatch cleavage analysis. A potential pitfall for all procedures based on analysis of amplified DNA is the coamplification of maternal sequences. This may be avoided by a careful dissection of maternal decidua from fetal trophoblast, by using an amount of chorionic villi not inferior to 5-10 mg and by reducing the number of amplifying cycles to approximately 20. Monitoring the presence of co-amplified maternal sequences by the analysis of polymorphic sequences is strongly recommended. Future perspectives consist of preimplantation diagnosis by biopsy of the morula or blastula or ova genotyping by analysis of the second polar body.

Molecular characterization of beta-thalassemia in the Sardinian population

This study reports the molecular characterization of beta-thalassemia in the Sardinian population. Three thousand beta-thalassemia chromosomes from prospective parents presenting at the genetic service were initially analyzed by dot blot analysis with oligonucleotide probes complementary to the most common beta-thalassemia mutations in the Mediterranean at-risk populations. the mutations which remained uncharacterized by this approach were defined by denaturing gradient gel electrophoresis (DGGE) followed by direct sequence analysis on amplified DNA. We reconfirmed that the predominant mutation in the Sardinian population is the codon 39 nonsense mutation, which accounts for 95.7% of the beta-thalassemia chromosomes. The other two relatively common mutations are frameshifts at codon 6 (2.1%) and at codon 76 (0.7%), relatively uncommon in other Mediterranean-origin populations. In this study we have detected a novel beta-thalassemia mutation, i.e., a frameshift at codon 1, in three beta-thalassemia chromosomes. The DGGE procedure followed by direct sequencing on amplified DNA is a powerful approach for the characterization of unknown mutations in this genetic system. The results herein presented allowed an expansion of the applicability of prenatal diagnosis by DNA analysis, to all couples at risk for beta-thalassemia in our population.

Promoter mutations producing mild beta-thalassaemia in the Italian population

In this study we have investigated the molecular basis for a mild form of beta-thalassaemia in three patients of Italian descent. In two, belonging to different families and affected by a mild and late-presenting form of thalassaemia major, direct sequencing of amplified DNA detected a C----T substitution at position -87 of the beta-globin gene in the compound heterozygous state either with codon 39 nonsense mutation or beta +IVSI, nt 110 mutation. The -87 (C----T) mutation has been previously described, in combination with the beta +IVSI, nt 110 mutation, in a single patient with thalassaemia intermedia. Both our patients showed a more severe phenotype as compared to that resulting from compound heterozygosity for a severe beta-thalassaemia mutation and another promoter mutation (-87, C----G) at the same position. In the third patient with the thalassaemia intermedia phenotype, we detected a novel promoter mutation, consisting in a C----A substitution at position -86, in combination with the codon 39 nonsense mutation. The results of this study indicate that different nucleotide substitutions affecting the proximal CACCC box of the beta-globin gene in combination with severe beta-thalassaemia, produce a mild form of thalassaemia ranging in severity from thalassaemia intermedia to late-presenting thalassaemia major.

Epidemiological and clinical correlations with genetic characteristics of Wilms' tumor: results of the Brazilian Wilms' Tumor Study Group

The epidemiological and clinical features of Wilms' tumor (WT) were analyzed in 176 patients admitted to the Brazilian WT Study Group. The occurrence of congenital anomalies (9.1%) and the M:F ratio (0.83) were comparable to those observed by the US National WT Study and the International Society of Pediatric Oncology trials. Bilateral cases were younger on average than unilateral cases (37.2 vs. 45.0 months). Ethnic group and gender were also associated with age, with non-white children being generally older (46.1 months) than whites (39.5 months), and boys being younger than girls (37.0 vs. 46.1 months). However, the most important factor in association with age at diagnosis was disease stage. No early disease patients were diagnosed after 8 years of age (mean: 37.5 months), whereas 10% of those with advanced disease were diagnosed between the ages of 8 and 10 years (mean: 56.3 months). There were no clear distinctions in age distributions on the basis of the presence of tumor multicentricity, intra- or perilobar nephroblastomatosis, and of a combination of putative genetic determinants. The mean age at diagnosis for cases with congenital defects was higher than that for the remaining patients. Some of the study results are in support of the recessive oncogene model for WT. However, the possible confounding effect of disease stage and the strong interdependence of the remaining factors may be masking important relations in regard to mutational events occurring during embryogenesis.

Peroxidase from Astragalus maritimus: purification and properties

A peroxidase has been purified to homogeneity from Astragalus maritimus seeds using ammonium sulfate precipitation and chromatography on DEAE-cellulose and hydroxylapatite. The purification obtained was 255 fold. The enzyme preparations were homogenous by the criteria of SDS-PAGE and analytical gel electrofocusing. The protein contained 0.11% of iron that corresponds to a minimum molecular size of 50,700. Determinations of molecular size by SDS-PAGE gave values of 48,000 +/- 1,000 while the one obtained by Sephadex gel filtration was 49,000. The pH optimum of the enzyme was 6.0. The activation energy was estimated to be 6 Kcal/mol. The prosthetic group was shown to be ferriprotoporphyrin IX. The presence of 13% neutral sugars was found. The spectrophotometric analysis showed the presence, in the visible region, of absorption maxima at 403, 490 and 633 nm. The Rz value (A403/A275) was 2.7.