Timely Monitoring of SARS-CoV-2 RNA Fragments in Wastewater Shows the Emergence of JN.1 (BA.2.86.1.1, Clade 23I) in Berlin, Germany

The importance of COVID-19 surveillance from wastewater continues to grow since case-based surveillance in the general population has been scaled back world-wide. In Berlin, Germany, quantitative and genomic wastewater monitoring for SARS-CoV-2 is performed in three wastewater treatment plants (WWTP) covering 84% of the population since December 2021. The SARS-CoV-2 Omicron sublineage JN.1 (B.2.86.1.1), was first identified from wastewater on 22 October 2023 and rapidly became the dominant sublineage. This change was accompanied by a parallel and still ongoing increase in the notification-based 7-day-hospitalization incidence of COVID-19 and COVID-19 ICU utilization, indicating increasing COVID-19 activity in the (hospital-prone) population and a higher strain on the healthcare system. In retrospect, unique mutations of JN.1 could be identified in wastewater as early as September 2023 but were of unknown relevance at the time. The timely detection of new sublineages in wastewater therefore depends on the availability of new sequences from GISAID and updates to Pango lineage definitions and Nextclade. We show that genomic wastewater surveillance provides timely public health evidence on a regional level, complementing the existing indicators.

Removal of Trace Organic Contaminants by Parallel Operation of Reverse Osmosis and Granular Activated Carbon for Drinking Water Treatment

In response to increasingly stringent restrictions for drinking water quality, a parallel operation of two common technologies, low-pressure reverse osmosis (LPRO) and activated carbon filtration (ACF), was investigated in a comprehensive five-month pilot study for the removal of 32 typical trace organic contaminants (TrOCs) from Rhine bank filtrates employing a semi- technical plant. TrOCs have been divided into three groups: polyfluorinated aliphatic compounds; pharmaceuticals, pesticides and metabolites; in addition to volatiles, nitrosamines and aminopolycarboxylic acids, which were also examined. The net pressure behavior, normalized salt passage and rejection of TrOCs by LPRO were investigated and compared with ACF operation. In addition, autopsies from the leading and last membrane modules were performed using adenosine triphosphate (ATP), total organic carbon (TOC), ICP-OES and SEM-EDX techniques. Generally, rather stable LPRO membrane performance with limited membrane fouling was observed. TrOCs with a molecular weight of ≥ 150 Da were completely retained by LPRO, while the rejection of di- and trichloro compounds improved as the filtration progressed. ACF also showed significant removal for most of the TrOCs, but without desalination. Accordingly, the ACF and LPRO can be operated in parallel such that the LPRO permeate and the ACF-treated bypass can be mixed to produce drinking water with adjustable hardness and significantly reduced TrOCs.

Multicomponent physical exercise with simultaneous cognitive training to enhance dual-task walking of older adults: a secondary analysis of a 6-month randomized controlled trial with 1-year follow-up

BACKGROUND

About one-third of people older than 65 years fall at least once a year. Physical exercise has been previously demonstrated to improve gait, enhance physical fitness, and prevent falls. Nonetheless, the addition of cognitive training components may potentially increase these effects, since cognitive impairment is related to gait irregularities and fall risk. We hypothesized that simultaneous cognitive-physical training would lead to greater improvements in dual-task (DT) gait compared to exclusive physical training.

METHODS

Elderly persons older than 70 years and without cognitive impairment were randomly assigned to the following groups: 1) virtual reality video game dancing (DANCE), 2) treadmill walking with simultaneous verbal memory training (MEMORY), or 3) treadmill walking (PHYS). Each program was complemented with strength and balance exercises. Two 1-hour training sessions per week over 6 months were applied. Gait variables, functional fitness (Short Physical Performance Battery, 6-minute walk), and fall frequencies were assessed at baseline, after 3 months and 6 months, and at 1-year follow-up. Multiple regression analyses with planned comparisons were carried out.

RESULTS

Eighty-nine participants were randomized to three groups initially; 71 completed the training and 47 were available at 1-year follow-up. DANCE/MEMORY showed a significant advantage compared to PHYS in DT costs of step time variability at fast walking (P=0.044). Training-specific gait adaptations were found on comparing DANCE and MEMORY: DANCE reduced step time at fast walking (P=0.007) and MEMORY reduced gait variability in DT and DT costs at preferred walking speed (both trend P=0.062). Global linear time effects showed improved gait (P<0.05), functional fitness (P<0.05), and reduced fall frequency (-77%, P<0.001). Only single-task fast walking, gait variability at preferred walking speed, and Short Physical Performance Battery were reduced at follow-up (all P<0.05 or trend).

CONCLUSION

Long-term multicomponent cognitive-physical and exclusive physical training programs demonstrated similar potential to counteract age-related decline in physical functioning.

Does multicomponent physical exercise with simultaneous cognitive training boost cognitive performance in older adults? A 6-month randomized controlled trial with a 1-year follow-up

Background

Cognitive impairment is a health problem that concerns almost every second elderly person. Physical and cognitive training have differential positive effects on cognition, but have been rarely applied in combination. This study evaluates synergistic effects of multicomponent physical exercise complemented with novel simultaneous cognitive training on cognition in older adults. We hypothesized that simultaneous cognitive–physical components would add training specific cognitive benefits compared to exclusively physical training.

Methods

Seniors, older than 70 years, without cognitive impairment, were randomly assigned to either: 1) virtual reality video game dancing (DANCE), 2) treadmill walking with simultaneous verbal memory training (MEMORY), or 3) treadmill walking (PHYS). Each program was complemented with strength and balance exercises. Two 1-hour training sessions per week over 6 months were applied. Cognitive performance was assessed at baseline, after 3 and 6 months, and at 1-year follow-up. Multiple regression analyses with planned comparisons were calculated.

Results

Eighty-nine participants were randomized to the three groups initially, 71 completed the training, while 47 were available at 1-year follow-up. Advantages of the simultaneous cognitive–physical programs were found in two dimensions of executive function. “Shifting attention” showed a time×intervention interaction in favor of DANCE/MEMORY versus PHYS (F[2, 68] =1.95, trend P=0.075, r=0.17); and “working memory” showed a time×intervention interaction in favor of DANCE versus MEMORY (F[1, 136] =2.71, trend P=0.051, R²=0.006). Performance improvements in executive functions, long-term visual memory (episodic memory), and processing speed were maintained at follow-up in all groups.

Conclusion

Particular executive functions benefit from simultaneous cognitive–physical training compared to exclusively physical multicomponent training. Cognitive–physical training programs may counteract widespread cognitive impairments in the elderly.

Pododermatitis in Captive and Free-Ranging Greater Flamingos (Phoenicopterus roseus)

Pododermatitis is frequent in captive flamingos worldwide, but little is known about the associated histopathologic lesions. Involvement of a papillomavirus or herpesvirus has been suspected. Histopathologic evaluation and viral assessment of biopsies from 19 live and 10 dead captive greater flamingos were performed. Selected samples were further examined by transmission electron microscopy and immunohistochemistry. Feet from 10 dead free-ranging greater flamingos were also evaluated. The histologic appearance of lesions of flamingos of increasing age was interpreted as the progression of pododermatitis. Mild histologic lesions were seen in a 3-week-old flamingo chick with no macroscopic lesions, and these were characterized by Micrococcus-like bacteria in the stratum corneum associated with exocytosis of heterophils. The inflammation associated with these bacteria may lead to further histologic changes: irregular columnar proliferations, papillary squirting, and dyskeratosis. In more chronic lesions, hydropic degeneration of keratinocytes, epidermal hyperplasia, and dyskeratosis were seen at the epidermis, as well as proliferation of new blood vessels and increased intercellular matrix in the dermis. Papillomavirus DNA was not identified in any of the samples, while herpesvirus DNA was seen only in a few cases; therefore, these viruses were not thought to be the cause of the lesions. Poor skin health through suboptimal husbandry may weaken the epidermal barrier and predispose the skin to invasion of Micrococcus-like bacteria. Histologic lesions were identified in very young flamingos with no macroscopic lesions; this is likely to be an early stage lesion that may progress to macroscopic lesions.

Effects of simultaneously performed cognitive and physical training in older adults

Background

While many studies confirm the positive effect of cognitive and physical training on cognitive performance of older adults, only little is known about the effects of simultaneously performed cognitive and physical training. In the current study, older adults simultaneously performed a verbal working memory and a cardiovascular training to improve cognitive and motor-cognitive dual task performance. Twenty training sessions of 30 minutes each were conducted over a period of ten weeks, with a test session before, in the middle, and after the training. Training gains were tested in measures of selective attention, paired-associates learning, executive control, reasoning, memory span, information processing speed, and motor-cognitive dual task performance in the form of walking and simultaneously performing a working memory task.

Results

Sixty-three participants with a mean age of 71.8 ± 4.9 years (range 65 to 84) either performed the simultaneous training (N = 21), performed a single working memory training (N = 16), or attended no training at all (N = 26). The results indicate similar training progress and larger improvements in the executive control task for both training groups when compared to the passive control group. In addition, the simultaneous training resulted in larger improvements compared to the single cognitive training in the paired-associates task and was able to reduce the step-to-step variability during the motor-cognitive dual task when compared to the single cognitive training and the passive control group.

Conclusions

The simultaneous training of cognitive and physical abilities presents a promising training concept to improve cognitive and motor-cognitive dual task performance, offering greater potential on daily life functioning, which usually involves the recruitment of multiple abilities and resources rather than a single one.

Acute tryptophan depletion increases experimental nausea but also induces hunger in healthy female subjects

BACKGROUND

Acute tryptophan depletion (ATD) is an experimental model to reduce central serotonin levels.

METHODS

Thirty-eight healthy female subjects were randomly assigned to two groups (ATD and control) in a randomized, double-blinded parallel-group design. Following a standardized and balanced amino acid diet (including 1.21 g tryptophan) on the first day, they received either a protein drink without tryptophan (but substituted by other amino acids) (ATD condition) or the balanced protein drink with tryptophan (control condition) 24 h later. Four hours after its consumption, they were exposed to a standard rotation procedure. Symptom ratings (SR), ratings of hunger and mood scores were taken prior to rotation, at each break, and 15 and 30 min thereafter, together with saliva cortisol samples.

KEY RESULTS

Five subjects could not tolerate the entire rotation procedure and were excluded from analysis. For the remaining n = 33, SR and hunger ratings were higher during ATD than during control conditions, but mood was unaffected. Cortisol levels rose significantly with rotation but were unaffected by ATD. High baseline cortisol levels were associated with lower SR during rotation. The protective effects of morning cortisol were pronounced during the menstrual and follicular phase of the cycle and not present during ovulation and the luteal phase.

CONCLUSIONS & INFERENCES

Acute tryptophan depletion is associated with increased symptoms of nausea in healthy female subjects when exposed to body rotation. Acute tryptophan depletion also increases hunger rating. These opposite effects may indicate independent actions of the serotonin on central and peripheral functions.

Comparing age effects in normally and extremely highly educated and intellectually engaged 65 - 80 year-olds: potential protection from deficit through educational and intellectual activities across the lifespan

Education and cognitive activity have been suggested to protect against cognitive decline in old age. However, little is known about the long-term effects of extremely high levels of education and intellectual activity across the lifespan. The present study investigated the extent to which these two variables may moderate the age-related differences in cognitive performance in old adults. Therefore, story recall, paired-associates learning, reading span and letter digit performance of 62 university professors (mean age = 72.47) were compared with those of a representative sample of 196 participants of the Zurich Longitudinal Study of Cognitive Aging (mean age = 73.04). The results demonstrate that the highly educated sample performed significantly better than the normally educated sample in the paired-associates learning and reading span test. Furthermore, age effects were found in the letter digit as well as in the paired-associates learning test. While the normally educated sample demonstrated an age-related decrease in the paired-associates learning test, the performance of the highly educated sample actually increased with increasing age. These findings suggest that extremely high levels of education and intellectual activity may postpone age-related deficits in paired-associates learning tasks, but not in speed of processing tasks.

STK11 status and intussusception risk in Peutz-Jeghers syndrome

BACKGROUND

Peutz-Jeghers syndrome (PJS) is caused by germline STK11 mutations and characterised by gastrointestinal polyposis. Although small bowel intussusception is a recognised complication of PJS, risk varies between patients.

OBJECTIVE

To analyse the time to onset of intussusception in a large series of PJS probands.

METHODS

STK11 mutation status was evaluated in 225 PJS probands and medical histories of the patients reviewed.

RESULTS

135 (60%) of the probands possessed a germline STK11 mutation; 109 (48%) probands had a history of intussusception at a median age of 15.0 years but with wide variability (range 3.7 to 45.4 years). Median time to onset of intussusception was not significantly different between those with identified mutations and those with no mutation detected, at 14.7 years and 16.4 years, respectively (log-rank test of difference, chi(2) = 0.58, with 1df; p = 0.45). Similarly no differences were observed between patient groups on the basis of the type or site of STK11 mutation.

CONCLUSIONS

The risk of intussusception in PJS is not influenced by STK11 mutation status.

Recessive missense mutations in LAMB2 expand the clinical spectrum of LAMB2-associated disorders

Congenital nephrotic syndrome is clinically and genetically heterogeneous. The majority of cases can be attributed to mutations in the genes NPHS1, NPHS2, and WT1. By homozygosity mapping in a consanguineous family with isolated congenital nephrotic syndrome, we identified a potential candidate region on chromosome 3p. The LAMB2 gene, which was recently reported as mutated in Pierson syndrome (microcoria-congenital nephrosis syndrome; OMIM #609049), was located in the linkage interval. Sequencing of all coding exons of LAMB2 revealed a novel homozygous missense mutation (R246Q) in both affected children. A different mutation at this codon (R246W), which is highly conserved through evolution, has recently been reported as causing Pierson syndrome. Subsequent LAMB2 mutational screening in six additional families with congenital nephrotic syndrome revealed compound heterozygosity for two novel missense mutations in one family with additional nonspecific ocular anomalies. These findings demonstrate that the spectrum of LAMB2-associated disorders is broader than previously anticipated and includes congenital nephrotic syndrome without eye anomalies or with minor ocular changes different from those observed in Pierson syndrome. This phenotypic variability likely reflects specific genotypes. We conclude that mutational analysis in LAMB2 should be considered in congenital nephrotic syndrome, if no mutations are found in NPHS1, NPHS2, or WT1.

Germline Wilms tumor suppressor gene (WT1) mutation leading to isolated genital malformation without Wilms tumor or nephropathy

Mutations of the Wilms tumor suppressor gene (WT1 ) have been described only in patients with syndromes associated with urogenital malformation and Wilms tumor or nephropathy. We present a male patient with an isolated genital malformation caused by a WT1 mutation.

Par4 is a coactivator for a splice isoform-specific transcriptional activation domain in WT1

The Wilms' tumor suppressor protein WT1 is a transcriptional regulator involved in differentiation and the regulation of cell growth. WT1 is subject to alternative splicing, one isoform including a 17-amino acid region that is specific to mammals. The function of this 17-amino acid insertion is not clear, however. Here, we describe a transcriptional activation domain in WT1 that is specific to the WT1 splice isoform that contains the 17-amino acid insertion. We show that the function of this domain in transcriptional activation is dependent on a specific interaction with the prostate apoptosis response factor par4. A mutation in WT1 found in Wilms' tumor disturbs the interaction with par4 and disrupts the function of the activation domain. Analysis of WT1 derivatives in cells treated to induce par4 expression showed a strong correlation between the transcription function of the WT1 17-amino acid insertion and the ability of WT1 to regulate cell survival and proliferation. Our results provide a molecular mechanism by which alternative splicing of WT1 can regulate cell growth in development and disease.

Evidence for susceptibility genes to familial Wilms tumour in addition to WT1, FWT1 and FWT2

Three loci have been implicated in familial Wilms tumour: WT1 located on chromosome 11p13, FWT1 on 17q12-q21, and FWT2 on 19q13. Two out of 19 Wilms tumour families evaluated showed strong evidence against linkage at all three loci. Both of these families contained at least three cases of Wilms tumour indicating that they were highly likely to be due to genetic susceptibility and therefore that one or more additional familial Wilms tumour susceptibility genes remain to be found.

Ten novel mutations found in Aniridia

Aniridia (AN) is a sight-threatening congenital ocular disorder characterized by iris hypoplasia, corneal pannus, foveal and optic nerve hypoplasia, cataract formation, and glaucoma. In two-thirds of the patients, AN is inherited in an autosomal dominant fashion with almost complete penetrance but variable expression. The remaining cases are sporadic. Aniridia has been shown to be associated with mutations in the PAX6 gene, located on chromosome 11p13, telomeric to the Wilms' tumor predisposition gene (WT1). This paper describes 14 mutations in the PAX6 gene in patients with AN. Among these 14 mutations, 10 have been unpublished until now. They result most probably in haploinsufficiency and consequently in a reduced protein level of functional PAX6 protein. The mutations reported here are scattered all over the gene, including the paired-box, the glycine-rich region, the homeobox, and the proline-serine-threonine (PST)-rich region.

Genomic structure, alternative transcripts and chromosome location of the human LIM domain binding protein 1 gene LDB1

By protein interaction screening using a radioactive LMO2 protein probe we have isolated a LIM domain binding protein. The gene shows high homology to independently isolated genes from mouse, Xenopus and Drosophila called Ldb1/Nli/Clim-2, Xldb1 and Chip, respectively. The human and mouse genes differ by only two amino acids, suggesting that the gene that we have isolated is the human homologue. Here we describe the genomic organization, alternative transcript forms and the chromosome mapping of the human gene LDB1 (alias NLI). The gene is spread over at least 12 kb and has 11 exons. Preceding the described ATG initiation site in the mouse a highly conserved region between mouse, chicken and human was detected with a second possible in frame initiation site coding for further 36 amino acids. An alternative splice site adding six nucleotides corresponding to the addition of two amino acids at the end of exon 10 was found. The gene was mapped to chromosome 10q24-->q25 by in situ hybridization, a region frequently deleted in many types of cancer. Fine mapping with a radiation hybrid panel localized the gene in the interval between the markers D10S603 and D10S540.

Extraintestinal polyps in Peutz-Jeghers syndrome: presentation of four cases and review of the literature. Deutsche Peutz-Jeghers-Studiengruppe

Peutz-Jeghers syndrome (PJS) is a rare hereditary disorder characterized by hamartomatous polyps in the gastrointestinal tract and typical pigment lesions. Extraintestinal polyps have rarely been reported. Possible sites include the respiratory tract, urogenital tract, and gallbladder. We here describe four cases of extraintestinal polyps in PJS patients and review the literature on the need for operative therapy of extraintestinal polyps in PJS. Three nonrelated patients were examined who had PJS and polyps in the gallbladder; the fourth patient had PJS and recurrent choanal polyps. Surgery has so far been performed only for symptomatic polyps: one laparoscopic cholecystectomy and removal of the choanal polyps for recurrent infections of the respiratory tract. The remaining two patients reported no symptoms from the extraintestinal polyps. No malignant transformation was found in these patients, nor has such been reported in the literature on PJS. The frequent observation of this manifestation in our patients raises the question of clinical management: Is prophylactic surgery indicated? Since malignant transformation of PJS polyps in the intestine is extremely rare we see no reason for operative therapy as long as the polyps are small and asymptomatic. Regular sonographic controls are recommended since the risk of malignant transformation cannot be ruled out at present.

Bilateral Wilms tumor in a boy with severe hypospadias and cryptochidism due to a heterozygous mutation in the WT1 gene

Mutations in the WT1 gene causing Wilms tumors were first reported in WAGR syndrome (Wilms tumor, Aniridia, Genitourinary malformation, mental Retardation) and Denys Drash syndrome (pseudohermaphroditism, Wilms tumor, nephropathy), but only in a few patients with hypospadias and cryptorchidism without other signs of Denys Drash (DDS) or WAGR syndrome WT1 mutations were identified. We report a boy, who was born in 1989 with hypospadias and bilateral cryptorchidism. Previous karyotyping and endocrine studies had ruled out any known cause of male pseudohermaphroditism. Subsequently, he developed a bilateral Wilms tumor, which was detected by palpation at the age of 15 months during a routine visit by the general pediatrician. Because of its extensive size, surgery and chemotherapy were needed for treatment. Analysis of the WT1 gene was performed 5 y after diagnosis and revealed a C to T transition in one allele generating a stop codon at codon 362 and subsequently leading to a truncated protein with loss of its ability to bind to DNA. No signs of DDS or WAGR syndrome are present in the boy. The work up of this patient and the so far known few comparable cases from the literature lead to the conclusion that in newborns with severe urogenital malformations not due to known chromosomal or endocrine disorders mutational screening of the WT1 gene should be performed, to evaluate the high risk of developing a Wilms tumor. We favor mutational screening in these patients as an easy tool for investigation, because in the future it will probably decrease the necessity of frequent control visits in patients without a WT1 mutation.

A high proportion of mutations in the BRCA1 gene in German breast/ovarian cancer families with clustering of mutations in the 3' third of the gene

We have analyzed 61 German breast and breast/ovarian cancer families for BRCA1 mutations using single-strand conformation polymorphism analysis (SSCP) followed by sequencing. Forty-seven of the families had at least three cases (at least two under 60 years) and 14 families had only two cases of breast/ovarian cancer (at least one under 50 years). Twenty-eight families were breast/ovarian and 33 were breast cancer-only families. Eighteen mutations in BRCA1 were detected in 11/28 breast/ovarian cancer families and 7/33 breast cancer families and none in the families with only two cases. We identified 17 truncation mutations (8 frameshift, 7 nonsense and 2 splice variants) and one missense mutation. Seven of these are novel and two, the 5382insC and 5622C-->T mutations, occurred in two apparently unrelated families. The genotype of the two families with the 5382insC mutation is compatible with the rare haplotype segregating with the 5382insC mutation in different populations, further supporting its European origin. One unclassified missense alteration, R841W, was found in one family but did not segregate with the disease, suggesting that it is more likely a polymorphism. We also report and discuss the sequence of several new unclassified single-nucleotide changes first identified by SSCP. Of the 18 mutations, 13 occurred in the 3' third of the gene (end of exon 11-24) and ovarian cancers were found in eight of these families.

Spectrum of early onset nephrotic syndrome associated with WT1 missense mutations

We investigated 17 children with nephrotic syndrome (NS) of early onset (14 aged < 1 year) and rapid progression to end-stage renal disease for the presence of mutations in the Wilms' tumor suppressor gene WT1 on chromosome 11. In eight children (7 genotypic males) an association with Wilms' tumor and/or ambiguous genitalia (Denys-Drash syndrome) was observed. In these eight and two additional female patients with NS only constitutional missense mutations in the WT1 gene were detected; four children presented the so-called hot spot mutation in exon 9 (R394N) and six had different mutations in exons 8 and 9 (4 not previously described). Renal biopsy showed diffuse mesangial sclerosis in eight and focal segmental sclerosis in two cases. End-stage renal disease was reached either concomitantly or within four months after onset of NS in seven of ten patients. A unilateral Wilms' tumor was found before or concomitant with NS in four children (3 males, 1 female). From the seven genotypic males with WT1 mutations, five presented ambiguous genitalia and two a female phenotype. No mutation of the WT1 gene was found in seven other children with isolated congenital or infantile NS with or without DMS who appeared to have a slower progression than the first group. It is proposed that patients with early onset, rapidly progressive NS and diffuse mesangial or focal segmental sclerosis should be tested for WT1 mutations to identify those at risk for developing Wilms' tumor.

Contiguous pattern spreading in patients with Hodgkin's disease

BACKGROUND

In 1966, Rosenberg and Kaplan hypothesized that Hodgkin's disease (HD) arises at a discrete primary site and subsequently spreads in a predictable manner via functionally contiguous lymph nodes. However, their results were not statistically evident. It was our aim to describe the spreading in the lymphatic system more precisely and to confirm their postulate.

METHODS

Between 1971 and 1992, 297 patients underwent pathological staging for HD. Our subsequent evaluation was restricted to the 236 cases with cervical involvement (65 bilateral, 80 dextral and 91 sinistral), those with lymph nodes on the right side (65 + 80 = 145) being analyzed separately from those with tumours on the left (65 + 91 = 156). Spreading via the lymphatic system was assessed by scoring of the number of involved and uninvolved nodes in six regions, which are functionally contiguous in the lymph system but not necessarily anatomically neighboured. The number of 'gaps' (i.e. missed nodes) observed according to a systematic spreading model was compared with that expected (probability model) if a random course had been followed.

RESULTS

Of the 156 patients with left cervical HD, 117 (75%) had para-aortic or spleen involvement, 90 (58%) had mediastinal involvement, 65 (42%) had right cervical involvement, 50 (32%) had axillary involvement and 23 (15%) had inguinal involvement. Of the 145 patients with right cervical HD, 112 (77%) had mediastinal involvement, 89 (61%) had para-aortic or spleen involvement, 65 (44%) had left cervical involvement, 44 (30%) had axillary involvement and 16 (11%) had inguinal involvement. In patients with left or right cervical lymph nodes, the proportions observed with gaps in the spreading were 37 and 27% (SE 7%), respectively, whereas the corresponding values of gaps expected in a probability model if a random course of spreading had been followed would have been 84 and 73% (P = 0.0001 and 0.0001, respectively).

CONCLUSION

Our data support the concept that HD spreads in a predictable manner via functionally contiguous lymph nodes. In patients with right cervical lymph nodes, HD spreads via the upper mediastinum and pulmonary hila to the upper abdominal nodes and the spleen. In those with left cervical tumours, HD spreads directly to the abdomen (bypassing the mediastinum), then upward again via the pulmonary hila and upper mediastinum to the neck region (bilateral involvement) and from here it proceeds to the axillary nodes. Finally the inguinal nodes are involved.

Correlation of germ-line mutations and two-hit inactivation of the WT1 gene with Wilms tumors of stromal-predominant histology

The WT1 gene, located on chromosome 11p13, is mutated in a low number of Wilms tumors (WTs). Germ-line mutations in the WT1 gene are found in patients with bilateral WT and/or associated genital tract malformations (GU). We have identified 19 hemizygous WT1 gene mutations/deletions in 64 patient samples. The histology of the tumors with mutations was stromal-predominant in 13, triphasic in 3, blastemal-predominant in 1, and unknown in 2 cases. Thirteen of 21 patients with stromal-predominant tumors had WT1 mutations and 10 of these were present in the germ line. Of the patients with germ-line alterations, six had GU and a unilateral tumor, two had a bilateral tumor and normal GU tracts, and two had a unilateral tumor and normal GU. Three mutations were tumor-specific and were found in patients with unilateral tumors without GU. These data demonstrate a correlation of WT1 mutations with stromal-predominant histology, suggesting that a germ-line mutation in WT1 predisposes to the development of tumors with this histology. Twelve mutations are nonsense mutations resulting in truncations at different positions in the WT1 protein and only two are missense mutations. Of the stromal-predominant tumors, 67% showed loss of heterozygosity, and in one tumor a different somatic mutation in addition to the germ-line mutation was identified. These data show that in a large proportion of a histopathologically distinct subset of WTs the classical two-hit inactivation model, with loss of a functional WT1 protein, is the underlying cause of tumor development.