Anxiety-like behavior and anxiolytic treatment in the Rett syndrome natural history study

BACKGROUND

Rett syndrome (RTT) is a neurodevelopmental disorder most often related to a pathogenic variant in the X-linked MECP2 gene. Internalizing behaviors appear to be common, but standard methods of diagnosing anxiety are not readily applied in this population which typically has cognitive impairment and limited expressive language. This study aims to describe the frequency of anxiety-like behavior and anxiolytic treatments along with associated clinical features in individuals with RTT.

METHODS

Parental reports and medication logs provided data from 1380 females with RTT participating in two iterations of the multicenter U.S. RTT Natural History Study (RNHS) from 2006 to 2019.

RESULTS

Most participants with RTT (77.5%) had at least occasional anxious or nervous behavior. Anxiety was reported to be the most troublesome concern for 2.6%, and within the top 3 concerns for 10.0%, of participants in the second iteration. Parents directly reported treatment for anxious or nervous behavior in 16.6% of participants in the second iteration with most reporting good control of the behavior (71.6%). In the medication logs of both RNHS iterations, the indication of anxiety was listed for a similar number of participants (15% and 14.5%, respectively). Increased use of anxiolytics and selective serotonin reuptake inhibitors (SSRIs) was related to more frequent anxiety-like behaviors (P < 0.001), older age (P < 0.001), and mild MECP2 variants (P = 0.002).

CONCLUSION

Anxiety-like behavior is frequent at all ages and is a significant parental concern in RTT. Older individuals and those with mild MECP2 variants are more likely to be treated with medications. Better diagnosis and treatment of anxiety in RTT should be a goal of both future studies and clinical care.

TRIAL REGISTRATION

NCT00299312 and NCT02738281.

Phenotypic features in MECP2 duplication syndrome: Effects of age

BACKGROUND

MECP2 Duplication syndrome (MDS) is a rare X-linked genomic disorder that is caused by interstitial chromosomal duplications at Xq28 encompassing the MECP2 gene. Although phenotypic features in MDS have been described, there is a limited understanding of the range of severity of these features, and how they evolve with age.

METHODS

The cross-sectional results of N = 69 participants (ages 6 months-33 years) enrolled in a natural history study of MDS are presented. Clinical severity was assessed using a clinician-report measure as well as a parent-report measure. Data was also gathered related to the top 3 concerns of parents as selected from the most salient symptoms related to MDS. The Child Health Questionnaire was also utilized to obtain parental reports of each child's quality of life to establish disease burden.

RESULTS

The results of linear regression from the clinician-reported measure show that overall clinical severity scores, motor dysfunction, and functional skills are significantly worse with increasing age. Top concerns rated by parents included lack of effective communication, abnormal walking/balance issues, constipation, and seizures. Higher levels of clinical severity were also related to lower physical health quality of life scores as reported by parents.

CONCLUSIONS

The data suggest that increasing levels of clinical severity are noted with older age, and this is primarily attributable to motor dysfunction, and functional skills. The results provide an important foundation for creating an MDS-specific severity scale highlighting the most important domains to target for treatment trials and will help clinicians and researchers define clinically meaningful changes.

Motor evoked potential recovery with surgeon interventions and neurologic outcomes: A meta-analysis and structural causal model for spine deformity surgeries

OBJECTIVE

To improve estimates of motor evoked potential (MEP) performance during spine deformity surgeries by accounting for potential confounders.

METHODS

A meta-analysis of MEPs for spine deformity surgeries determined the probability of a MEP deterioration which recovered by the end of surgery, P(RSC), and the conditional probability of no new post-operative deficit given an RSC, P(NND|RSC), stratified by category of intraoperative adverse event associated with the MEP deterioration. A structural causal model (SCM) and propensity score matching accounted for intraoperative adverse events and patient diagnosis as potential confounders.

RESULTS

MEPs changes (either reversible, RSC or irreversible, IRREV) were reported for 295 of 5055 cases (6%) in 21 studies. The probability of no new motor deficit, P(NND), plotted against the probability of a RSC, P(RSC), for studies in the meta-analysis was highly significant (r = 0.71, p < 0.001). P(RSC) was 0.76 for an alert associated with correction, less for osteotomies (0.48, p = 0.0008), and tended to be higher for hypotension (0.92, p = 0.06). P(NND|RSC) was 0.94 for correction, less for positioning (0.82), and osteotomies (0.86), and greater for hypotension (1.0). In the SCM, a RSC after an alert was a highly significant and independent predictor of no new motor deficits (odds 25.2, p < 0.001).

CONCLUSION

There are significant differences in P(RSC) for hypotension and osteotomies, and in P(NND) for osteotomies and instrumentation, compared to correction. P(RSC) is a significant and independent predictor of outcomes.

SIGNIFICANCE

When MEPs are used for spine deformity surgeries, accounting for adverse events associated with an alert and patient diagnosis as potential confounders is expected to improve RSC prediction of post-operative outcomes and estimates of RSC efficacy in improving outcomes.

Characterizing the phenotypic effect of Xq28 duplication size in MECP2 duplication syndrome

Individuals with methyl CpG binding protein 2 (MECP2) duplication syndrome (MDS) have varying degrees of severity in their mobility, hand use, developmental skills, and susceptibility to infections. In the present study, we examine the relationship between duplication size, gene content, and overall phenotype in MDS using a clinical severity scale. Other genes typically duplicated within Xq28 (eg, GDI1, RAB39B, FLNA) are associated with distinct clinical features independent of MECP2. We additionally compare the phenotype of this cohort (n = 48) to other reported cohorts with MDS. Utilizing existing indices of clinical severity in Rett syndrome, we found that larger duplication size correlates with higher severity in total clinical severity scores (r = 0.36; P = 0.02), and in total motor behavioral assessment inventory scores (r = 0.31; P = 0.05). Greater severity was associated with having the RAB39B gene duplicated, although most of these participants also had large duplications. Results suggest that developmental delays in the first 6 months of life, hypotonia, vasomotor disturbances, constipation, drooling, and bruxism are common in MDS. This is the first study to show that duplication size is related to clinical severity. Future studies should examine whether large duplications which do not encompass RAB39B also contribute to clinical severity. Results also suggest the need for creating an MDS specific severity scale.

Scoliosis in Rett Syndrome: Progression, Comorbidities, and Predictors

BACKGROUND

Scoliosis is prominent in Rett syndrome (RTT). Following the prior report from the US Natural History Study, the onset and progression of severe scoliosis (≥40° Cobb angle) and surgery were examined regarding functional capabilities and specific genotypes, addressing the hypothesis that abnormal muscle tone, poor oral feeding, puberty, and delays or absence of sitting balance and ambulation may be responsible for greater risk in RTT.

METHODS

The multicenter RTT Natural History Study gathered longitudinal data for classic RTT, including mutation type, scoliosis, muscle tone, sitting, ambulation, hand function, and feeding. Cox regression models were used to examine the association between scoliosis and functional characteristics. All analyses utilized SAS 9.4; two-sided P values of <0.05 were considered significant.

RESULTS

A total of 913 females with classic RTT were included. Scoliosis frequency and severity increased with age. Severe scoliosis was found in 251 participants (27%), 113 of whom developed severe scoliosis during the follow-up assessments; 168 (18%) had surgical correction. Severe MECP2 mutations (R106W, R168X, R255X, R270X, and large deletions) showed a higher proportion of scoliosis. Individuals developing severe scoliosis or requiring surgery were less likely to sit, ambulate, or use their hands and were more likely to have begun puberty. Significant differences were absent for epilepsy rates, sleep problems, or constipation.

DISCUSSION

Scoliosis requires vigilance regarding the risk factors noted, particularly specific mutations and the role of puberty and motor abilities. Bracing is recommended for moderate curves and surgery for severe curves in accordance with published guidelines for scoliosis management.

Importance of genetic testing in global health during the evaluation of familial microcephaly

A focused genetic workup is useful in determining the cause of familial microcephaly, especially in the setting of mildly different phenotypes. As illustrated by this case from an impoverished international urban location, one must not assume the etiology for the apparent familial microcephaly is the same for all affected members.

Commentary : The value of intraoperative neurophysiological monitoring: evidence, equipoise and outcomes

The use of intraoperative neurophysiological monitoring (IONM) has grown despite an absence of randomized controlled trials that might unequivocally demonstrate improved outcomes. At issue is how to demonstrate value when other evidence indicates patient harms (opportunity cost) if IONM is withheld for the sake of randomization. In this article we review other non-randomized methods to assess the effects of IONM on post-operative outcomes. We also examine how clinical equipoise may resolve whether (or not) an anticipated controlled study is ethical. We conclude that the value of IONM in a particular surgical setting should be determined by a benefits/harms analysis based on all the available evidence.

Clinical severity and quality of life in children and adolescents with Rett syndrome

OBJECTIVE

The clinical features and genetics of Rett syndrome (RTT) have been well studied, but examination of quality of life (QOL) is limited. This study describes the impact of clinical severity on QOL among female children and adolescents with classic RTT.

METHODS

Cross-sectional and longitudinal analyses were conducted on data collected from an NIH-sponsored RTT natural history study. More than 200 participants from 5 to 18 years of age with classic RTT finished their 2-year follow-up at the time of analysis. Regression models after adjustment for their MECP2 mutation type and age at enrollment were used to examine the association between clinical status and QOL.

RESULTS

Severe clinical impairment was highly associated with poor physical QOL, but worse motor function and earlier age at onset of RTT stereotypies were associated with better psychosocial QOL; conversely, better motor function was associated with poorer psychosocial QOL.

CONCLUSIONS

Standard psychosocial QOL assessment for children and adolescents with RTT differs significantly with regard to their motor function severity. As clinical trials in RTT emerge, the Child Health Questionnaire 50 may represent one of the important outcome measures.

11p14.1 microdeletions associated with ADHD, autism, developmental delay, and obesity

Genomic copy number imbalances are being increasingly identified as an important cause of intellectual disability and behavioral abnormalities. The typical deletion in WAGR syndrome encompasses the PAX6 and WT1 genes, but larger deletions have been associated with neurobehavioral abnormalities and obesity. We identified four patients with overlapping interstitial deletions on 11p14.1 and extending telomeric to the WAGR critical domain. The minimal overlapping critical chromosomal region was 2.3 Mb at 11p14.1. The deletions encompass the BDNF and LIN7C genes that are implicated in the regulation of development and differentiation of neurons and synaptic transmission. All patients with this deletion exhibit variable degrees of developmental delay, behavioral problems, and obesity. Our data show that ADHD, autism, developmental delay, and obesity are highly associated with deletion involving 11p14.1 and provide additional support for a significant role of BDNF in obesity and neurobehavioral problems.

Mucolipidosis type IV: a subtle pediatric neurodegenerative disorder

The mucolipidoses are a heterogeneous group of autosomal recessive neurodegenerative lysosomal storage disorders. Mucolipidosis type IV is rare; it is seen predominantly in the Ashkenazi Jewish population and usually presents with global neurodevelopmental delays in infancy, subtle corneal opacifications or clouding, and very slowly progressive neurodegeneration over many years. Elevation of serum gastrin is reported; findings from x-rays of bone and joints and lysosomal studies are normal. Reported here are two cases of mucolipidosis type IV in children not of Ashkenazi Jewish origin who presented during infancy with nonspecific global psychomotor delays, generalized hypotonia, and mild corneal abnormalities, but remained undiagnosed for years. A rare gene mutation in MCOLN1 was confirmed in one of the two patients, in addition to abnormal serum gastrin levels. More striking was the length of time that these children eluded detection of their final diagnosis.

Longevity in Rett syndrome: analysis of the North American Database

OBJECTIVE

To determine longevity in Rett syndrome (RTT) from a large cohort.

STUDY DESIGN

The North American RTT Database allows the examination of longevity in a large cohort of individuals with RTT from the United States and Canada. This database contains information on 1928 individuals, 85.5% with typical RTT, 13.4% with atypical RTT, and 1.1% with a mutation in the methyl-CpG-binding protein 2 gene (MECP2) but not RTT. Kaplan-Meier analyses were performed to assess longevity.

RESULTS

Earlier decennial cohorts exhibited better survival than recent cohorts, with most participants surviving into middle age. Comparing overall survival in persons with typical RTT and atypical RTT revealed greater mortality in typical RTT across the observed lifespan (P < .0001). Comparing survival in persons with RTT and identified MECP2 mutations and persons with unknown MECP2 status demonstrated greater mortality in the latter group (P < .0001, log-rank test).

CONCLUSIONS

This analysis provides strong evidence for significant longevity in RTT and indicates the need for careful planning for long-term care of these women. The disproportionately greater survival seen in earlier time periods and in persons with atypical RTT may be attributed to more severely affected individuals dying before diagnosis in the former and to greater numbers with milder variants (ie, preserved speech and delayed onset) in the latter.

Microdeletion 15q13.3: a locus with incomplete penetrance for autism, mental retardation, and psychiatric disorders

BACKGROUND

Microdeletions within chromosome 15q13.3 are associated both with a recently recognised syndrome of mental retardation, seizures, and dysmorphic features, and with schizophrenia.

METHODS AND RESULTS

Based on routine diagnostic testing of approximately 8200 samples using array comparative genomic hybridisation, we identified 20 individuals (14 children and six parents in 12 families) with microdeletions of 15q13.3. Phenotypes in the children included developmental delay, mental retardation, or borderline IQ in most and autistic spectrum disorder (6/14), speech delay, aggressiveness, attention deficit hyperactivity disorder, and other behavioural problems. Both parents were available in seven families, and the deletion was de novo in one, inherited from an apparently normal parent in four, and inherited from a parent with learning disability and bipolar disorder in two families. Of the 14 children, six in five families were adopted, and DNA was available for only one of these 10 biological parents; the deletion was very likely inherited for one of these families with two affected children. Among the unavailable parents, two mothers were described as having mental retardation, another mother as having "mental illness", and one father as having schizophrenia. We hypothesise that some of the unavailable parents have the deletion.

CONCLUSIONS

The occurrence of increased adoption, frequent autism, bipolar disorder, and lack of penetrance are noteworthy findings in individuals with deletion 15q13.3. A high rate of adoption may be related to the presence of the deletion in biological parents. Unconfirmed histories of antisocial behaviours in unavailable biological parents raise the concern that future research may show that deletion 15q13.3 is associated with such behaviours.

Treatment of anal fissure with glyceryl trinitrate in patients referred for surgical management

BACKGROUND

A number of recent studies indicate that anal fissure may be treated by applying glyceryl trinitrate (GTN) ointment. The present study aims to determine the effectiveness and patient acceptability of GTN treatment for patients referred to a consultant surgeon.

METHODS

A prospective study of 65 consecutive patients referred to one surgeon (ALP) over a 12-month period was undertaken. All patients were offered 0.2% GTN ointment to be applied intra-anally four times daily for 4 weeks. Informed consent was obtained and review planned for 4 weeks.

RESULTS

Fourteen patients declined treatment and nine of the 14 (64%) subsequently underwent lateral sphincterotomy. Twelve of the 51 patients (18.5%) who accepted treatment could not complete it due to headache or persisting severe anal pain. Thirty-nine of the 51 patients (77%) were able to complete 4 weeks of treatment. Twenty-two of the 39 reported an improvement in symptoms. A total of 22 patients (43%) who started GTN treatment subsequently underwent lateral sphincterotomy.

CONCLUSIONS

Evidence from the present study suggests that GTN ointment has a place in the management of referred patients with severe and/or chronic anal fissure, but sphincterotomy remains an important treatment option for the majority.

Inhibition of beta-catenin translocation in rodent colorectal tumors: a novel explanation for the protective effect of nonsteroidal antiinflammatory drugs in colorectal cancer

In a rodent colorectal cancer model, nonsteroidal antiinflammatory drugs reduce tumor mass by increasing the rate of tumor cell apoptosis and decreasing proliferation. We have examined beta-catenin as a potential target for these agents in colorectal cancer. Carcinogen-treated rats were treated for 23 weeks with a range of nonsteroidal antiinflammatory drugs. Control animals received vehicle alone. Intracellular beta-catenin was examined using immunohistochemistry. In tumors from untreated animals, staining was seen in the cytoplasm and nucleus (median 24% of nuclei). The frequency of nuclear beta-catenin staining correlated directly with the volume of tumor and inversely with the rate of apoptosis. In tumors from treatment groups, the cytoplasmic staining for beta-catenin was unchanged; however, nuclear staining was absent except in the celecoxib group, where it was reduced to a median of 14%. Colorectal tumors from animals treated with NSAIDs show reduced levels of nuclear beta-catenin immunoreactivity.

Non-steroidal anti-inflammatory drugs with activity against either cyclooxygenase 1 or cyclooxygenase 2 inhibit colorectal cancer in a DMH rodent model by inducing apoptosis and inhibiting cell proliferation

BACKGROUND

Standard non-steroidal anti-inflammatory drugs (NSAIDs) reduce the risk of colorectal cancer by 40-60% but the mechanism by which this occurs is uncertain. Selective cyclooxygenase 2 inhibitors are potentially ideal chemopreventive agents as they are less toxic than standard NSAIDs. No study has compared the efficacy of these drugs at clinically relevant doses in a tumour model.

AIMS

To assess the efficacy of a range of NSAIDs with varying activity against the two cyclooxygenase isoforms in a rodent colorectal carcinogen model at anti-inflammatory doses and to explore the effect of NSAIDs on the rate of tumour apoptosis and proliferation.

METHODS

Colorectal tumours were induced in six week old Sprague-Dawley rats with five weekly doses of 1,2 dimethylhydrazine. Test agents were: indomethacin 2 mg/kg/day, meloxicam 0.6 mg/kg/day, celecoxib 6 mg/kg/day, and sulindac sulphone 40 mg/kg/day. Sulindac was tested at its chemoprotective dose of 20 mg/kg/day. After 23 weeks the number and volume of tumours per animal were recorded. Histology was performed. Tumour apoptosis was quantified on haematoxylin-eosin sections. Tumour proliferation was quantified using an immunohistochemical stain for bromodexoyuridine incorporation.

RESULTS

Test agents effectively reduced the number and volume of tumours developing in the treatment period. In all groups there was an increase in the rate of tumour apoptosis and a reduced rate of proliferation.

CONCLUSIONS

These data suggest that the chemopreventive effect of NSAIDs is independent of their cyclooxygenase inhibitory profile. One potential mechanism for their action may be through induction of apoptosis and inhibition of proliferation.

Non-steroidal anti-inflammatory drugs with different cyclooxygenase inhibitory profiles that prevent aberrant crypt foci formation but vary in acute gastrotoxicity in a rat model

BACKGROUND

Standard non-steroidal anti-inflammatory drugs (NSAIDs) reduce the risk of colorectal cancer; however, their use as preventive agents is limited by their inherent toxicity. Drugs that selectively inhibit cyclooxygenase-2 (COX-2) may be useful in this setting as they are supposedly less toxic. No study has directly compared the ability of standard NSAIDs and selective COX-2 inhibitors to inhibit colorectal cancer at clinically relevant doses.

METHODS

Aberrant crypt foci (ACF) were induced in Sprague-Dawley rats by using 1,2-dimethylhydrazine (DMH). Test agents or vehicle were then administered for 3 weeks, twice daily through orogastric gavage. At the end of this period, the number and multiplicity of ACF were determined. The agents tested at equivalent anti-inflammatory doses were: sulindac and indomethacin (standard NSAIDs), meloxicam (selective COX-2 inhibitor), celecoxib (specific COX-2 inhibitor) and sulindac sulfone (no known COX activity). Acute gastrotoxicity of NSAID in rats was compared by using quantitative histology.

RESULTS

All test agents reduced the number of ACF. There was a 42% reduction with indomethacin, 46% with sulindac, 46% with meloxicam, 22% with celecoxib and 36% with sulindac sulfone. Only the COX-2 inhibitors caused no significant gastrotoxicity in rats.

CONCLUSIONS

Cyclooxygenase-2 inhibitors are potentially ideal chemopreventive agents as they inhibit ACF and are not gastrotoxic.

5-aminosalicyclic acid and olsalazine inhibit tumor growth in a rodent model of colorectal cancer

The ability of 5-aminosalicylic acid and olsalazine to inhibit colonic aberrant crypts and tumors was investigated in 1,2-dimethylhydrazine-treated rats. The effect of these drugs on the rates of tumor apoptosis and proliferation was studied as potential mechanisms for their action. 5-Aminosalicylic acid reduced the number of aberrant crypt foci by over one third, while olsalazine had no effect on this parameter. However, both agents effectively reduced tumor number and load, increased the rate of tumor apoptosis, and reduced the rate of tumor cell proliferation. In conclusion, 5-aminosalicylic acid and olsalazine are both ultimately effective chemopreventive agents in this model; however, only 5-aminosalicylic acid inhibited the formation of aberrant crypt foci. The inhibitory effect of these agents in tumors is related to the inhibition of proliferation and the induction of apoptosis.

Inhibition of rat colon tumors by sulindac and sulindac sulfone is independent of K-ras (codon 12) mutation

Nonsteroidal anti-inflammatory drug (NSAID) use reduces the risk of colorectal cancer by 40-50%. Previous studies suggest that effective inhibition of colorectal cancer by NSAIDs may be dependent on the presence or absence of a K-ras mutation. This study was aimed at determining the relationship between inhibition of colorectal cancer by sulindac and sulindac sulfone and the presence of activating K-ras mutations in the 1,2-dimethylhydrazine dihydrochloride rat model. Sulindac (20 mg x kg(-1) x day(-1)), sulindac sulfone (40 mg x kg(-1) x day(-1)), or vehicle was administered orally to male Sprague-Dawley rats for a 4-wk period beginning 20 wk after tumor induction. Tumor number and volume were measured before treatment by laparotomy and colonoscopy and again after treatment. Sulindac and sulindac sulfone treatment significantly reduced the number and volume of colorectal tumors compared with control rats. For K-ras (codon 12) mutation detection, frozen tumor tissue was collected at the endpoint. We found K-ras codon 12 mutations in 11 of 21 (52%) control tumors. The proportion of tumors with K-ras mutations in the sulindac-treated group [5 of 8 (62%); odds ratio = 1.51 (95% confidence interval = 0.29, 8.33)] and the proportion of sulindac sulfone-treated tumors [9 of 14 (64%); odds ratio = 1.63 (95% confidence interval = 0.41, 6.66)] were not significantly different from controls. Tumor inhibition did not correlate with K-ras (codon 12) mutation status, which suggests that the mechanism of inhibition of rat colorectal cancer by sulindac and sulindac sulfone is independent of K-ras mutation.

Sulindac inhibits colorectal tumour growth, but not prostaglandin synthesis in the rat

We have determined the dose-response relationship between sulindac administration and inhibition of tumour growth in the rat. The effect of tumour-inhibiting doses of sulindac on the production of prostaglandin E in tumours and macroscopically normal colon was then examined. Growth of pre-existing tumours was significantly reduced following administration of sulindac at 0.1 (P=0.004), 1 (P=0.01), 3 (P<0.001) and 10 mg/kg b.d. (P=0.002) for 4 weeks. There was no significant difference in prostaglandin E synthesis between tumours from control rats and those treated with sulindac at either 3 or 10 mg/kg b.d. (P=0.09 and 0.4, respectively). Prostaglandin E synthesis was reduced by 33 and 32% in macroscopically normal tissue from these treatment groups. These data show that sulindac inhibits tumour growth at low doses and do not support a role for the inhibition of prostaglandin synthesis, by sulindac, in the inhibition of tumour growth.

Autism and maternally derived aberrations of chromosome 15q

Of the chronic mental disabilities of childhood, autism is causally least well understood. The former view that autism was rooted in exposure to humorless and perfectionistic parenting has given way to the notion that genetic influences are dominant underlying factors. Still, identification of specific heritable factors has been slow with causes identified in only a few cases in unselected series. A broad search for genetic and environmental influences that cause or predispose to autism is the major thrust of the South Carolina Autism Project. Among the first 100 cases enrolled in the project, abnormalities of chromosome 15 have emerged as the single most common cause. The four abnormalities identified include deletions and duplications of proximal 15q. Other chromosome aberrations seen in single cases include a balanced 13;16 translocation, a pericentric inversion 12, a deletion of 20p, and a ring 7. Candidate genes involved in the 15q region affected by duplication and deletion include the ubiquitin-protein ligase (UBE3A) gene responsible for Angelman syndrome and genes for three GABA(A) receptor subunits. In all cases, the deletions or duplications occurred on the chromosome inherited from the mother.

Intersitial deletion of 20p: new candidate region for Hirschsprung disease and autism?

We describe a patient with Hirschsprung disease and autism. High-resolution karyotyping indicated that the patient has an interstitial deletion of 20p11.22-p11.23. Microsatellite analysis showed a deletion involving a 5-6 cM region from the maternally derived chromosome 20. The deleted region is proximal to, and does not overlap, the recently characterized Alagille syndrome region. This region of 20p has not yet been implicated in Hirschsprung disease or autism. However, this region contains several genes that could plausibly contribute to any phenotype that includes abnormal neural development.

The microvascular structure of the normal colon in rats and humans

The colonic microcirculation may be expected to have a central role in the absorptive, secretory, and protective functions of the colon. To characterize the microvascular structure of the colon in rats and humans, microvascular casts were prepared and examined by scanning electron microscopy. Quantitative measures of the microvasculature were obtained from histological sections. The overall organization of microvessels was found to be similar in the rat and human colon. Capillaries in the colonic mucosa formed a honeycomb-like network around each of the mucosal glands. This capillary plexus was supplied by arterioles which divide into their capillary branches at the level of the submucosa. Mucosal capillaries drain into venules at the luminal surface of the mucosa. Venules then pass to submucosal veins without receiving further capillary branches. Examination of vascular casts also showed that in both the rat and the human colon, there was an increased density of subluminal capillaries in the cecum and proximal colon compared to that of the rest of the colon. This was supported by quantitative measures which indicated a significantly greater microvascular surface area in the rat cecum (24.1 mm2/mm3) compared to that of the midcolon (19.8 mm2/mm3) (P = 0.04) and the distal colon (19.1 mm2/mm3) (P = 0.03). Similarly in the human colon there was a significantly greater total microvascular volume in the proximal colon (13.4%) compared to that of the distal colon (7.7%) (P < 0.0005) and there was a significantly greater total microvascular surface area in the proximal colon (22.4 mm2/mm3) compared to that of the distal colon (17.5 mm2/mm3)(P=0.032). This study details quantitative vascular data for the colon in rats and humans which has not previously been documented, despite its important role in the absorptive function of the colon and in many disease processes affecting the colon. These data provide the normal values with which pathological conditions of the colon which affect the vasculature can be compared.

Prenatal diagnosis of mosaic 4p- in a fetus with trisomy 21

Mosaicism for the Wolf-Hirschhorn syndrome, del(4)(p16), is extremely rare and has not been reported in association with a numerical chromosome abnormality. We report the prenatal diagnosis of mosaic del(4)(p16) and non-mosaic trisomy 21 in a 16-week female fetus. The pregnancy ended in spontaneous abortion at 34 weeks secondary to fetal demise. The fetus had features of both 4p- and trisomy 21.

Microvascular structure of benign and malignant tumors of the colon in humans

Studies of experimental tumors in rodents indicate that there are morphological abnormalities of the tumor microcirculation compared to normal tissues. The aim of this study was to examine the structure of the microvasculature in benign and malignant colonic tumors in humans using microvascular casting techniques. There were 15 adenocarcinomas, four benign sporadic adenomas, and three specimens from patients with familial adenomatous polyposis (FAP). A cast of the microvessels of these tumors was prepared by intraarterial administration of acrylic resin (Mercox) and the cast examined by scanning electron microscopy. Quantitative measures of the microvasculature were obtained from histological sections using stereological techniques in four carcinomas, two sporadic adenomas, and 12 adenomas from patients with FAP. Vascular casts of benign colonic adenomas showed that the microvasculature had a similar organization to normal colon. However, capillaries and venules were elongated and had increased diameters compared to normal. In adenomas greater than 3 mm in diameter, there was an increased density of microvessels in the spaces between tumor cells. Vascular casts of colonic carcinomas were characterized by a disorganized structure and increased density of microvessels. The organization of microvessels within carcinomas had a similar overall pattern to normal colon. However, the increased number and density of microvessels resulted in formation of nodular clusters of capillaries, formation of "sheets" of frequently anastomosing capillaries, or almost complete packing of the interstitial spaces of the tumor by capillaries in places. Most capillaries had a long and tortuous course and numerous capillary sprouts were identified. Tumor microvessels had greater mean diameters than normal. Extravasation of resin from microvessels in carcinomas was frequently seen. The vascular volume of carcinomas (23.1% +/- 12.2), sporadic adenomas (16.3% +/- 3.4), and adenomas > 3 mm diameter in patients with FAP (17.7% +/- 3.0) were significantly greater than in normal colon (11.0% +/- 4.2). This study indicates that there is an increased vascular density in benign and malignant tumors of the colon compared to normal colon. The presence of profusely anastomotic microvessels and frequent capillary sprouts is evidence of active neovascularization and suggests control of tumor growth could be achieved by modifiers of angiogenesis.

Deletion involving D15S113 in a mother and son without Angelman syndrome: refinement of the Angelman syndrome critical deletion region

Deletions of 15q11-q13 typically result in Angelman syndrome when inherited from the mother and Prader-Willi syndrome when inherited from the father. The critical deletion region for Angelman syndrome has recently been restricted by a report of an Angelman syndrome patient with a deletion spanning less than 200 kb around the D15S113 locus. We report here on a mother and son with a deletion of chromosome 15 that includes the D15S113 locus. The son has mild to moderate mental retardation and minor anomalies, while the mother has a borderline intellectual deficit and slightly downslanting palpebral fissures. Neither patient has the seizures, excessive laughter and hand clapping, ataxia or the facial anomalies which are characteristic of Angelman syndrome. The proximal boundary of the deletion in our patients lies between the D15S10 and the D15S113 loci. Our patients do not have Angelman syndrome, despite the deletion of the D15S113 marker. This suggests that the Angelman syndrome critical deletion region is now defined as the overlap between the deletion found in the previously reported Angelman syndrome patient and the region that is intact in our patients.

Laparoscopic assisted right hemicolectomy with Valtrac BAR (Biofragmentable Anastomotic Ring) ileotransverse anastomosis

Laparoscopic techniques have been employed in a group of medically compromised patients requiring right hemicolectomy, permitting a shorter and lower placed abdominal incision than may have been expected with a conventional surgical approach. In eight patients requiring right hemicolectomy, full mobilization of the right colon from the caecum to the proximal transverse colon was performed laparoscopically. Resection and anastomosis then proceeded through a small right-sided transverse abdominal incision. End to end ileotransverse anastomosis was performed in each instance employing the Valtrac BAR (Biofragmentable Anastomotic Ring) compressive anastomotic technique. The average operating time was 133 min. There was no mortality, but one patient developed pulmonary complications and three developed minor wound infections. An additional three patients developed urinary tract infections. There were no anastomotic complications. The average postoperative stay was 10 days. This study has indicated that laparoscopic techniques can be successfully applied to large bowel surgery, and may be of benefit to high risk patients.

Sulindac inhibits the rate of growth and appearance of colon tumors in the rat

Sulindac (cis-5-fluoro-2-methyl-1-[p-(methylsulfinyl) benzylidene] indene-3-acetic acid), an inhibitor of prostaglandin synthesis, has been reported to cause regression of colon polyps in patients with familial polyposis coli and Gardner's syndrome. We examined the effect of sulindac on the growth of primary colon carcinomas in rats. Colon tumors were induced in 18 rats by repeated subcutaneous administration of dimethylhydrazine. The site and diameter of each tumor were measured via laparotomy and colonoscopy. Rats were randomized to receive either sulindac (10 mg/kg) twice daily or vehicle (0.5% methylcellulose). After 4 weeks of treatment, the site and size of tumors in the colon were again recorded. In eight rats receiving sulindac, no new tumors were identified, while in 10 control rats, 13 additional tumors were found after treatment. There was a significantly greater increase in size of the tumors in the control group (56.4 mm for 26 tumors) compared with the rats receiving sulindac (9.3 mm for 14 tumors). We report that sulindac inhibits the rate of development and the rate of growth of colon tumors in the rat.

Microvascular architecture of experimental colon tumors in the rat

Tumor cell proliferation is dependent upon concurrent growth of a supporting vasculature. This study aims to characterize the structural features of the microvasculature within a primary tumor model. There were 22 colon tumors induced in 16 rats by repeated administration of dimethylhydrazine. A cast of the microvessels was prepared by intraarterial administration of acrylic resin (Mercox). After corrosion of the tissue, the cast was examined by scanning electron microscopy. Tumors 2.6 to 12.0 mm in diameter were examined. Within polypoid carcinomas up to 5.7 mm in diameter, there were two distinct vascular zones, a luminal vascular zone continuous with the vasculature of normal mucosa and a central zone continuous with the normal submucosa and muscularis propria vessels. Within both vascular zones, the organization of microvessels had the same general pattern as in normal mucosa. However, in tumors with diameters greater than 5.7 mm, the vasculature was seen to be disorganized and of a greater density than normal. In the smallest tumors, few morphological changes were seen in the individual microvessels when compared to normal. However, with tumor growth, there was elongation and increased diameters of the microvessels within the tumor. Microvessels within the luminal zone of the tumors which could definitely be traced to veins had diameters of 50 to 100 microns (compared to 12 to 30 microns for normal venules). Individual microvessels varied in diameter along their course forming saccular dilations in places. Networks of frequently anastomosing microvessels were formed. Extravasation of resin occurred from some microvessels. Elongated vessels of uniform diameter which travel distances up to 2 mm without branching were seen and were probably arterioles. These appearances indicate that there are two distinct stages of development of the vasculature within primary tumors, an early phase where the tumor is supplied by the preexisting host microvessels, followed by a phase of proliferation of new vessels with abnormal morphological characteristics.

Acampomelic campomelic dysplasia

Two newborn infants with respiratory distress showed all the clinical and radiologic stigmata of the campomelic dysplasia except campomelia itself.