Modeling nitrous oxide production by a denitrifying-enhanced biologically phosphorus removing (EBPR) activated sludge in the presence of different carbon sources and electron acceptors

In this study, the IWA Activated Sludge Model No. 2d (ASM2d) was expanded to identify the most important mechanisms leading to the anoxic nitrous oxide (N₂O) production in the combined nitrogen (N) and phosphorus (P) removal activated sludge systems. The new model adopted a three-stage denitrification concept and was evaluated against the measured data from one/two-phase batch experiments carried out with activated sludge withdrawn from a local, large-scale biological nutrient removal wastewater treatment plant. The experiments were focused on investigating the effects of different external carbon sources (acetate, ethanol) and electron acceptors (nitrite, nitrate) on the mechanisms of N₂O production in enhanced biological P removal by polyphosphate accumulating organisms (PAOs) and external carbon-based denitrification by ordinary heterotrophic organisms (OHOs). The experimental results explicitly showed that N₂O production was predominantly governed by the presence of nitrite in the reactor regardless of the examined carbon source and the ratio COD/N in the reactor. The model was capable of accurately predicting (with R² > 0.9) the behavior of not only N₂O-N, but also NO₃-N, NO₂-N, soluble COD, and PO₄-P. The simulation results revealed that only OHOs were responsible for N₂O production, whereas the present denitrifying PAOs reduced only nitrate to nitrite.

New Eu²+ sites in KMgF₃:Eu²+ crystal

The luminescence properties of KMgF(3):Eu(2 + ) are investigated at different pressures in the temperature range 25-292 K. Five new Eu(2 + ) luminescence (NEL) lines due to the [Formula: see text] transition are identified at 362.49 nm (L(1)), 362.53 nm (L(2)), 360.72 nm (L(3)), 360.15 nm (L(4)) and 359.59 nm (L(5)) together with the line at 359.32 nm (L(0)) which is well known in KMgF(3):Eu(2 + ). The emission lines under excitation at 325 nm show a strong dependence on temperature. At 25 K the emission spectrum consists of only two sharp lines, L(1) and L(2). Three additional lines (L(3), L(4) and L(5)) begin to appear with increasing temperature. With a further increase in temperature from 150 to 292 K all the lines disappear except for the single sharp line at 359.32 nm (L(0)). The zero-phonon transition of line L(0) is accompanied by vibronic sidebands. A pressure shift of five NELs is estimated to be about - 0.6 cm( - 1) kbar( - 1) similarly to the shift of line L(0), while the lifetimes of the NELs are about 0.7 ms which is shorter than that (5.2 ms) of L(0) at 80 K. The new luminescence lines are attributed to the Eu(2 + ) ions occupying the K( + ) sites with fluorine vacancy (F( - ) center) complexes.

Competition between two types of anti-Stokes emission in Ho(3+)-activated ZBLAN glass

A competition between two anti-Stokes emissions has been observed and interpreted in ZBLAN glass activated by Ho(3+) ions. The first anti-Stokes emission intensity was seen to increase with temperature, whereas another, upconverted emission, was seen to decrease under the same conditions. Both observed tendencies are believed to be caused by the same effect: the multiphonon anti-Stokes excitation of the state responsible for the first emission. Analysis of the kinetics and fits of the theoretical model to experimental data are presented.

Diagnosis of late-infantile neuronal ceroid lipofuscinosis: a new sensitive method to assay lysosomal pepstatin-insensitive proteinase activity in human and animal specimens by capillary electrophoresis

Batten disease, or human late-infantile neuronal ceroid lipofuscinosis (LINCL) is a familiar progressive degenerative disease affecting children, caused by a deficiency of a lysosomal proteinase (tripeptidyl peptidase I, TPP-I) and characterized by the accumulation of autofluorescent storage bodies in the brain and other tissues of the body. Current methodology used to diagnose this disease needs to be improved in order to have less invasive techniques with higher resolution and shorter assay time. In this report, we discuss the potential merits of micellar electrokinetic chromatography as an excellent tool that requires minute samples but offers high resolution and a short running time for monitoring TPP-I activity in human and animal specimens.

New procedure of the Mitsunobu reaction as the key step in peptide nucleic acid (PNA) monomers synthesis

PNAs are relatively novel DNA analogues, intensively studied due to their potential as gene-targeted drugs with antigene and antisense properties. In 1996 we elaborated a new method of synthesis of PNA monomer backbones based on the Mitsunobu reaction with N-tosyl-protected (Tos) amino acid esters as acidic components of the reaction. Since the method used for the Tos group removal requires conditions incompatible with various functional groups, here we modified the procedure by replacing the tosyl group with o-nitrobenzenesulfonyl (o-NBS) group. Using the new procedure we obtained protected PNA monomer backbones with various amino acid side chains. The pseudodipeptide secondary amine groups were then deprotected by thiolysis, and after standard work-up acylated with thymin-1-ylacetic acid, to give the protected monomers. Since the deprotection of the secondary amine group occurs under mild conditions, the procedure is of general applicability and allows various modifications of PNA structure by using diverse beta-amino alcohols and alpha-amino acid esters.

Synthesis and characterization of new chiral peptide nucleic acid (PNA) monomers

PNAs are DNA analogues in which the nucleic acid's backbone is replaced by a chiral or achiral pseudopeptide backbone and nucleobases are attached to the backbone by methylene carbonyl linkers. The easy to modify PNA structure gives the possibility to obtain monomers, and subsequently oligomers, with improved properties. We have synthesised several new PNA monomers, starting from a series of 2'-substituted methyl N-(2-Boc-aminoethyl)glycinates. The pseudodipeptides were obtained using modified Kosynkina's method, based on the reductive amination of N-Boc-protected alpha-amino aldehydes [glycinal, isoleucinal, valinal, tryptophanal, serinal(Bzl), prolinal] with methyl glycinate. The compounds were then acylated with nucleic acid base derivatives by simplified procedure, and the purification was limited to the last step of the synthesis. The applied procedure is useful in synthesis of various chiral PNA monomers.

Bilateral 6-OHDA lesions to the hippocampus attenuate the facilitatory effect of CCK-8 us and caerulein on memory in rats

The involvement of dopaminergic projection to the hippocampus in the facilitatory effect of cholecystokinin-unsulphated octapeptide (CCK-8 us) and caerulein (CER) on memory motivated affectively was investigated in male rats. CCK-8 us and CER were given subcutaneously at the doses of 10 microg kg(-1)and 0.5 microg kg(-1), respectively, immediately after a single learning trial in a passive avoidance situation, after bilateral 6-OHDA lesions to the dentate gyrus of the hippocampus. In order to protect noradrenergic neurones against destruction by neurotoxin, 30 min before surgery rats were pre-treated intraperitoneally with 25 mg kg(-1)of desmethylimipramine, an inhibitor of noradrenaline uptake. Bilateral 6-OHDA lesions to the hippocampus significantly attenuate the facilitatory effect of CCK-8 us and CER on retention of passive avoidance behaviour evaluated 24 h after the learning trial. Neither, destruction of dopaminergic endings in the hippocampus, nor application of CCK-8 us and CER changed the spontaneous psychomotor activity of rats estimated in an 'open field' test. These results may indicate that the facilitatory effect of CCK-8 us and CER on memory motivated affectively is, in part, mediated by dopaminergic projection from the ventral tegmental area to the dentate gyrus of the hippocampus.

Disruption of temporo-entorhinal connections abolishes the facilitatory effect of angiotensins on memory in rats

It has been found in our laboratory that the positive influence of angiotensin II (AII) and its 3-7 fragment [AII(3-7)] on learning and memory processes is mediated by the excitatory amino acids, since it was abolished by NMDA receptor antagonists. The purpose of the present study was to investigate whether bilateral disruption of glutamatergic temporo- entorhinal connections may have an influence on the facilitatory effect of both angiotensin peptides on memory motivated affectively. The bilateral transections of temporo-entorhinal connections were made in 27 male rats 10 days before testing the influence of intracerebroventricular AII and AII(3-7) injection on retrieval of a passive avoidance response. Twenty-seven additional rats served as sham-operated controls. Twenty-five lesioned and 25 sham-operated animals were accepted to the final analysis. AII and its 3-7 fragment significantly improved the retrieval process in sham-operated groups of rats. Bilateral disruption of temporo-entorhinal connections totally abolished the facilitatory effect of both angiotensins on recall of information in a passive avoidance situation. Moreover, bilateral disruption of temporo-entorhinal connections markedly but not significantly attenuated crossings of squares, evaluated in an open field test, without an influence on rearings and bar approaches. These results may suggest that in the facilitatory effect of AII and AII(3-7) on memory motivated affectively involves reciprocal glutamatergic connection between lateral entorhinal cortex and temporal cortex.

Mutational analysis of the defective protease in classic late-infantile neuronal ceroid lipofuscinosis, a neurodegenerative lysosomal storage disorder

The late-infantile form of neuronal ceroid lipofuscinosis (LINCL) is a progressive and ultimately fatal neurodegenerative disease of childhood. The defective gene in this hereditary disorder, CLN2, encodes a recently identified lysosomal pepstatin-insensitive acid protease. To better understand the molecular pathology of LINCL, we conducted a genetic survey of CLN2 in 74 LINCL families. In 14 patients, CLN2 protease activities were normal and no mutations were identified, suggesting other forms of NCL. Both pathogenic alleles were identified in 57 of the other 60 LINCL families studied. In total, 24 mutations were associated with LINCL, comprising six splice-junction mutations, 11 missense mutations, 3 nonsense mutations, 3 small deletions, and 1 single-nucleotide insertion. Two mutations were particularly common: an intronic G-->C transversion in the invariant AG of a 3' splice junction, found in 38 of 115 alleles, and a C-->T transition in 32 of 115 alleles, which prematurely terminates translation at amino acid 208 of 563. An Arg-->His substitution was identified, which was associated with a late age at onset and protracted clinical phenotype, in a number of other patients originally diagnosed with juvenile NCL.

Classification of the neuronal ceroid-lipofuscinoses: expansion of the atypical forms

The neuronal ceroid-lipofuscinoses (NCL) are a group of different genetic diseases. The major types of NCL are expressed by six forms which represent different clinicopathologic and genetic forms. These are CLN-1, Infantile; CLN-2, Late Infantile; CLN-3, Juvenile; CLN-4, Adult-Recessive; CLN-5, Adult-Dominant; and CLN-6, Early Juvenile. The distinction between CLN-4 and CLN-5 is still disputatious. CLN-6 has been called CLN-5. A seventh classification of NCL represents from 12 to 20% of those afflicted. This group consists of an extensive array of atypical types of ceroid-lipofuscin accumulation in the secondary lysosomes of neurons and cells of other tissues (e.g., skin, conjunctiva, and lymphocytes) or by presumed clinical and genetic relationships. The authors have identified 15 atypical subtypes of NCL. These as a group are here described as a seventh form. Further biochemical, molecular, and genetic studies will identify more precisely the phenotypic and genotypic expression of these "minor" forms of NCL.

New X-linked mental retardation (XLMR) syndrome with distinct facial appearance and growth retardation

We report on 2 brothers and their nephew with an apparently new X-linked mental retardation (XLMR) syndrome characterized by a distinct facial appearance, growth retardation, and severe mental retardation. The facial traits included triangular shape; bifrontal narrowness; malar flatness; blepharophimosis; very deeply set eyes; epicanthus inversus; bulbous nose; low hairline; low-set, deeply cupped, and protruding ears; short ill-defined philtrum; and thin tented upper lip. These facial anomalies are particularly striking and recognizable even at birth. The boys were small for gestational age and remained below -2 SD in growth parameters. With age, large joint contractures developed. Pectus excavatum was apparent at birth but became more obvious with age. Global developmental delay was evident in infancy. The brothers were nonverbal while their nephew spoke simple words. Optic atrophy, esotropia, nystagmus, and spastic diplegia were evident. They were self-abusive, hyperactive, and poorly coordinated. CT scans demonstrated atrophic hydrocephalus. No EEG abnormalities were detected. Karyotypes were 46,XY and fragile X negative. Routine chemistries; amino, organic, and uronic acids; oligosaccharides; lysosomal enzymes; and very long chain fatty acids were normal. Remarkable phenotypic similarity between these brothers and their nephew and lack of manifestations in their mothers makes X-linked recessive inheritance likely. This syndrome, which does not appear to have been reported previously, adds to the delineation of XLMR.

Somatosensory evoked potentials in hemimegalencephaly and lissencephaly: anatomo-functional correlations

Four patients with hemimegalencephaly and four with lissencephaly were studied by median nerve somatosensory evoked potentials. The peripheral conduction velocity and the conduction time between the brachial plexus (Erb's point) and cervical cord were normal in both malformations. In hemimegalencephaly, the cortical components were absent on the malformed hemisphere but normal on the healthy side, whereas in lissencephaly an abnormal, prolonged N20 wave was recorded bilaterally. The difference presumably relates to the absence of normal cortical lamination in hemimegalencephaly and to the presence of a 'four-layered' cortex in lissencephaly.

Analysis of neocortex in three males with the fragile X syndrome

Fragile X [fraX] syndrome is a common hereditary disorder associated with a fragile site marker at Xq27.3 which clinically presents as a form of mental retardation (MR). Postmortem investigation of 3 fraX positive males with mild to moderate MR did not document any gross neuropathological changes. Golgi analysis of neocortical dendritic spine morphology extended our previous observations of immature, long, tortuous spines in one adult case of fraX (Rudelli, et al., Acta Neuropathologica 67:289-295, 1985) to 2 new cases. Evidence for similar dendritic spine abnormalities was found, although Golgi analysis was less than optimal because of incomplete dendritic stain impregnation. Neocortical intra-layer cell density was also investigated in all 3 cases. Cresyl violet stained neurons were counted in 10 randomly selected fields in neocortical layers II-VI of cingulate and temporal association areas (Brodmann's areas 23 and 38). Neuron counts in fraX and control neocortex showed no significant differences. Thus, abnormal dendritic spine morphology with preservation of neuronal density appears to characterize the neocortex in individuals with this common form of mental retardation.

Agenesis of the corpus callosum: clinical, neuroradiological and cytogenetic studies

This study examined 35 patients with developmental disabilities who were referred for diagnostic evaluation that later revealed agenesis of the corpus callosum (ACC) by computerized tomography (CT). Sixteen had partial ACC, six had complete ACC, and one had a hypoplastic corpus callosum. In the other twelve cases, ACC existed, but the degree of callosal defect was not specified. Other intracranial defects were frequently present. Clinically, 15 patients (43%) had a history of seizures, 28 (82%) were mentally retarded or developmentally delayed and an additional five patients (15%) possessed borderline intelligence, and 10 (29%) had cerebral palsy. Ocular, spinal, and orofacial abnormalities were often present. Detailed summaries of these findings are given in Table I. Although several genetic causes of ACC have been identified, in the vast majority, the etiology is assumed to be multifactorial. In our study, two patients had trisomy 8 mosaicism and 11 (35%) had a family history of developmental disability. A review of the literature on chromosomal abnormalities in acalossal patients revealed 81 additional cases, which are discussed and outlined in Table II.

Behavioral effects of angiotensin II and angiotensin II-(4-8)-pentapeptide in rats

One nM of angiotensin II (AII) or angiotensin II-(4-8)-pentapeptide [AII(4-8)] given intracerebroventricularly did not affect locomotor and exploratory behavior of rats in open field. AII significantly increased and AII(4-8) did not affect vertical activity of animals in electromagnetic motimeter. Neither of the peptides influenced horizontal activity in the motimeter. Both peptides intensified stereotypy produced by apomorphine and amphetamine. AII significantly improved, while AII(4-8) did not affect, consolidation of memory of the correct way to food in T-maze. Similarly, AII increased and AII(4-8) did not change the rate of acquisition of conditioned avoidance responses in a shuttle-box. Of the two examined peptides only AII significantly improved retrieval of memory of the passive avoidance behavior. The results show that AII(4-8) influences central dopaminergic system but, unlike its parent peptide AII, has no apparent effect on memory.

Farber lipogranulomatosis: an unusual presentation in a black child

Farber disease, a rare, inherited condition of lipid metabolism usually appears within the first two months of life. The patients may die in the first few years of life or may live into the second decade. We believe this patient to be the first black American reported with Farber disease. Additionally, the characteristics of the disease in this patient were at variance with previously reported cases.

A profile of cognitive deficit in females from fragile X families

Fragile X, a recently discovered X-linked syndrome, is usually associated with mental retardation in affected males. Less consistent findings have been described for females. neuropsychological evaluation of seven nonretarded females from fragile X families suggested a characteristic profile: on Wechsler IQ tests, a positive Verbal-Performance score difference and lower subtest scaled scores on Arithmetic, Digit Span, Block Design, and Object Assembly; on the Wide Range Achievement Test, a lower score on Arithmetic than on Reading or Spelling; and on the Benton Visual Retention Test, defective recall. These results suggest the existence of X-linked learning disability in females.

Cystathionine disappearance with neuronal loss: a possible neuronal marker

Cystathionine is an important intermediate in the transsulfuration pathway of methionine catabolism and is normally present in high concentration in the human CNS. We have measured the concentration of cystathionine, other amino acids, and brain proteins in the cerebral cortex, cerebellar cortex and spinal cord of two cases with ceroid lipofuscinosis. Neuropathological and biochemical studies of Case 1, at an advanced stage, Case 2, at an early stage, and five controls were correlated with clinical and neurological findings. The concentration of an unidentified 54,000 Dalton protein was greatly increased in Case 1 as observed by 2-D gel electrophoresis. Neurons and cystathionine were almost totally absent from the cortex and cerebellum of Case 1, while they were slightly reduced in Case 2, in comparison to control brains. These studies suggest that cystathionine may be specifically located within neurons. We present for the first time the observation that there was a strikingly low brain concentration of cystathionine, a potential neuronal marker, in an advanced stage of a neurodegenerative process.

Sanfilippo disease, type A with some features of ceroid lipofuscinosis

Light microscopic, histochemical and electron-microscopic studies were made on the brain of a case (No. 1) with Sanfilippo disease, type A. In this case pigment preparations of the isocortex have been demonstrated. Ultrastructural investigations of the skin biopsies (his two male siblings) were also studied (cases 2, 3). Our three siblings of MPS III A, have demonstrated ceroid lipofuscin storage in the brain (case No. 1) and skin biopsies (cases No. 2 and 3) in addition to histological features of MPS. The biochemical studies (enzymatic identification) were made in the cultures of fibroblasts. Also, urine quantitative studies for MPS and N-sulfonate to hexosamino ratio were performed.

Frequency of agenesis of the corpus callosum in the developmentally disabled population as determined by computerized tomography

Agenesis of the corpus callosum (ACC) is an infrequent congenital abnormality that has been diagnosed by necropsy, surgery, pneumoencephalography, computerized tomography (CT), and magnetic resonance imaging. The reported prevalence has varied as a function of disability status of the population studied and diagnostic technique. This report found 33 cases of ACC in a consecutive series of 1,447 CTs of developmentally disabled individuals. The prevalence, 2.3%, is consistent with studies using other techniques. However, the significantly higher (p less than 0.01) rate from 1978 to 1979 suggests an initial tendency of neuroradiologists to over-diagnose ACC, and CT data from the 1970s may need to be reexamined.

Adult fragile X syndrome. Clinico-neuropathologic findings

Fragile X syndrome [fra (X)] is currently accepted as the second most frequent chromosomal disorder associated with developmental disability. Although next to Down syndrome in frequency, no postmortem studies of confirmed adult cases had been reported. The autopsy examination of a 62-year-old, moderately retarded man with the fra (X) syndrome confirmed the preferential involvement of cerebral and testicular structures in this disorder. Dendritic spine abnormalities of the type observed in trisomic chromosomal disorders were associated with synaptic immaturity. Severe testicular hypogonadism accompanied bilateral macro-orchidism, normal penis, and unilateral hydrocele. Valvular, articular, and testicular interstitial compartments showed normal histochemical staining characteristics for glycoproteins and lipids.

Distal duplication 14q: report of three cases and further delineation of the syndrome

Three cases of distal duplication 14q are presented. The first two cases are cousins in a kindred segregating a balanced translocation t(14;18)(q31;q23). The third case resulted from a maternal translocation t(14;18)(q24;p11). By review of these cases and those previously reported, a distal duplication 14q syndrome is further delineated. Common features include postnatal growth retardation, mental retardation, hypotonia, microcephaly, slanted palpebral fissures, ocular hypertelorism, sparse eyelashes and eyebrows, nasal dysmorphism, tented lip, micrognathia, posteriorly rotated ears, and minor skeletal anomalies.

Low sulfated glycosaminoglycans are excreted in patients with the Lowe syndrome

Glycosaminoglycans (GAGs) were prepared from the urine of three patients and from normal individuals by cetylpyridinium chloride precipitation and Pronase digestion. The GAGs were analyzed by electrophoresis, anion-exchange chromatography, and enzymatic and chemical degradation. Each of the three patients showed a four- to fivefold increase in urinary GAG excretion compared to normal controls and in one patient a tenfold increase was measured during a period of behavioral agitation which included joint swelling. Urinary GAGs from affected individuals were characterized by a high proportion of low sulfated molecules. The predominant low sulfated component was chondroitin-4-sulfate (C4S); however, small amounts of chondroitin-6-sulfate (C6S) were also present. Heparan sulfate (HS) was present in normal proportion (5-10%) and most of it was not low sulfated. Abnormal excretion of chondroitin (Ch), hyaluronic acid (HA), and dermatan sulfate (DS) was not detected. These findings suggest that the clinical manifestations of Lowe syndrome may be caused by a defect in GAG metabolism.

An autopsy case of hemimegalencephaly

This case report is a neuropathological study of a ten-month-old infant with unilateral megalencephaly . In this anomaly neuronal migration defect and disturbances of cortical organization resulting in micropolygyria were the most striking neuropathological feature.

A clinical neuropathological study of the fetal alcohol syndrome

Five patients with the clinical diagnosis of fetal alcohol syndrome (FAS) died at the ages of 8 and 4 months and 17, 4 and 2 days. Neuropathological examination revealed microencephalic brains in all cases, without morphological evidence of maturation delay. One of them showed agenesis of the corpus callosum and hypoplasia of the cerebellar vermis. Five of them had only small dysgenetic changes, consisting mainly of glio or glioneuronal meningeal or parenchymal heterotopias. Our findings indicate that the brain is commonly but not affected in FAS. The influence of alcohol and its metabolites, as well as undernutrition, and use of other drugs by the mothers, should be taken into account as possible etiologic factors.

Production and characterization of monoclonal antibodies specific for a glycosylated polypeptide of human cytomegalovirus

Nine hybrid cell lines producing antibodies specific for cytomegalovirus (CMV) antigen were obtained after fusion of P3/X63-Ag8 myeloma cells with spleen cells from BALB/c mice immunized with CMV complement-fixing antigen. By the immunoblot technique, five of nine antibodies (4D11, 7B4, 7D2, 8E3, and 8E10) were identified as being reactive to a CMV glycosylated polypeptide with molecular weight of 66,000 (GP66). Four other antibodies (1B8, 8E9, 4D2, and 7E2) appeared to be reactive with CMV antigen(s) only if the antigen was not denatured by sodium dodecyl sulfate. These remain unassigned until further studies are done. With the enzyme-linked immunosorbent assay (ELISA), competitive bindings were performed with a constant amount of horseradish peroxidase-conjugated antibody and various concentrations of unconjugated homologous and heterologous antibodies on CMV antigen-coated ELISA wells, and the antigenic determinant specific for each antibody was determined. The nine antibodies could be classified into six different groups, each group reacting with a different epitope or a different region with two or more antigenic determinants which are so close to each other that they cause binding inhibition. They are groups A (4D11), B (7B4, 8E10), C (7D2), D (4D2, 7E2, 8E9), E (8E3), and F (1B8). The extent of competition among antibodies within each group was the same. By using the two antibodies that reacted with different epitopes on GP66, a double-antibody sandwich ELISA method was developed. The method was sensitive enough to detect as little as 50% of the antigen present in one infected cell or 0.000245 U of CMV complement-fixing antigen per test well. Other strains of CMV (David, Kerr, Espilat, C-87, and five clinical isolates) gave positive results, whereas herpes simplex virus types 1 and 2, varicella-zoster virus and Epstein-Barr virus nuclear antigen preparations did not. By the indirect immunofluorescence assay, antibodies 4D11 and 8E3 were able to detect GP66 in the nucleus of CMV-infected F-5000 human embryonic fibroblasts as early as 2 h postinfection and were superior in this respect to the remaining seven antibodies tested. By the double-antibody sandwich ELISA, the presence of GP66 in CMV-infected cells was detected as early as 2 h postinfection.

Atypical Down syndrome and partial trisomy 21

A case of "atypical" Down Syndrome (DS), where the proposita did not exhibit all of the clinical features of DS and had de novo partial trisomy 21, was studied. Results from phenotypic, chromosome banding and superoxide dismutase (SOD) gene dosage studies suggest a karyotype of 46,XX,-12,+t(12pter to 12qter::21q21 to 21q22.?2). Additional studies of such atypical cases will provide more precise sublocalization for both gene and phenotypic mapping of the bands that are responsible for the DS phenotype.

Monosomy 21 syndrome: further delineation including clinical, neuropathological, cytogenetic and biochemical studies

Only six cases of living newborns with apparently complete monosomy 21 have been reported. All the previous cases with the exception of the present case died between 3 weeks and 20 months. Only one of these cases had a postmortem examination. The subject of this report was previously described at the age of 6 years (Davis et al. 1976). He survived until 11 years old and is the oldest known case of complete monosomy 21. We report here the clinical presentation over 11 years, results of gene dosage studies, cytogenetic analysis, and the neuropathological postmortem examination.

Lissencephaly: two distinct clinico-pathological types

The present study is a review of four new cases of lissencephaly and two others previously reported. This study demonstrates that lissencephaly is a gross feature of the brain occurring in two different groups of cortical malformations. The first group, the classic agyria syndrome extensively analyzed by Jellinger and Rett [8] includes two types of abnormal cortical organization. They may be found in familial syndromes and also can appear sporadically. The second group includes smooth brains with the internal features of polymicrogyria and a more severely disorganized cortex. This type appears in familial lissencephaly in the cerebro-oculo-muscular syndrome, belonging to the same group as Fukuyama congenital-cerebro-muscular dystrophy. The other incidences of this type of cortical malformation require further investigation. The clinico-pathological differential diagnosis of two types of lissencephaly are also discussed.