bluuebunny/crossref_metadata_2025 huggingface dataset:
The importance of being marginal: Norma Ford Walker and a Canadian school of medical genetics
Authors: Miller Fiona
Published: October 2002

This study reviews the development of a medical genetics research tradition in Toronto, Canada. This research tradition, what I call the “Ford Walker school,” was forged in the 1930s in an iconoclastic mold. It was female‐dominated in an era when leading‐edge science was definitely not “women's work.” It emerged in a leading research university, but in a country that lagged in the sciences. These social relations of gender and nation symbolized and sustained a marginality that was reinforced by the substantive concerns of members of this research school. They adopted a service orientation toward medicine, were sympathetic to heterodox approaches to genetic and medical science, and were principally reliant on a marginal research tool—dermatoglyphics. Despite this marginality, Norma Ford Walker was among the founding members of the institutions of human and medical genetics in North America in the postwar period. She forged a research tradition that served as the basis for further developments in medical genetics in Toronto and educated a generation of students, many of them women, who went on to populate and then institutionalize the growing science and practice of medical genetics in Canada. The heterodox approach of the early Ford Walker school was displaced as the field grew in the postwar period. Yet many members of the research school retained dermatoglyphic technique and used it to contribute to progress in medical cytogenetics. In this article, I explore why the history of this marginal research school is important. © 2002 Wiley‐Liss, Inc.
Preferential transmission of the MTHFR 677 T allele to infants with down syndrome: Implications for a survival advantage
Authors: Hobbs Charlotte A. , Cleves Mario A. , Lauer Ronald M. , Burns Trudy L. , James S. Jill
Published: October 2002

We have examined the transmission frequencies of the methylenetetrahydrofolate reductase (MTHFR) 677 T and C alleles from heterozygous parents to children with Down syndrome (trisomy 21) in 202 Caucasian families. Our results indicated that the MTHFR 677T allele was transmitted to children with Down syndrome at a significantly higher rate than would be expected based on Mendelian inheritance patterns, and the C allele was transmitted at a significantly lower rate (P < 0.009). Transmission frequencies were also examined independently for maternally and paternally transmitted alleles to assess potential parent‐of‐origin effects. Because the vast majority of conceptions with trisomy 21 end in pregnancy loss, we questioned whether the observed preferential transmission of the T allele to this population of liveborn infants with Down syndrome could reflect a survival advantage. A plausible biochemical interpretation of these results is presented based on a maternal–fetal MTHFR 677T allele interaction in the context of the constitutive overexpression of three copies of the cystathionine beta synthase gene in the trisomy 21 fetus. Published 2002 Wiley‐Liss, Inc.
Tetrasomy 15q25.3 → qter resulting from an analphoid supernumerary marker chromosome in a patient with multiple anomalies and bilateral Wilms tumors
Authors: Hu J. , McPherson E. , Surti U. , Hasegawa S.L. , Gunawardena S. , Gollin S.M.
Published: October 2002

We describe a girl who had been followed since birth for apparent Shprintzen‐Goldberg syndrome (SGS), with macrosomia, long fingers and toes, and craniosynostosis, and presented at 4 years of age with bilateral Wilms tumors (also called nephroblastoma). Cytogenetic analysis of her peripheral blood revealed a de novo supernumerary marker chromosome. This stable marker chromosome is present in 19 of 20 lymphocytes analyzed, as well as in all 40 tumor cells (20 from each tumor) studied. Classical and molecular cytogenetic studies indicate that the marker is derived from an inverted duplication of chromosome 15q25.3 → qter and contains a neocentromere. The presence of this marker chromosome in our patient results in tetrasomy 15q25.3 → qter. The relationship between her genotype and phenotype are discussed in light of genes, including IGF1R and FES, mapped to the aneusomic segment. © 2002 Wiley‐Liss, Inc.
Prenatal diagnosis and confirmation of the acrofacial dysostosis syndrome type Rodriguez
Authors: Wessels M.W. , den Hollander N.S. , Cohen‐Overbeek T.E. , Lesnik Oberstein M.S. , Nash R.M. , Wladimiroff J.W. , Niermeijer M.F. , Willems P.J.
Published: October 2002

The group of acrofacial dysostosis (AFD) syndromes is very heterogeneous and contains many different entities. In 1990, Rodriguez et al. [1990: Am J Med Genet 35:484–489] described a new type of AFD characterized by severe mandibular hypoplasia, phocomelia and oligodactyly of the upper limbs, absence of fibulae, microtia, cleft palate, internal organ anomalies including arrhinencephaly and abnormal lung lobulation, and early lethality. We describe another case of AFD type Rodriguez, identified by prenatal ultrasonography at 25 weeks of gestation. © 2002 Wiley‐Liss, Inc.
Mutations in FOXL2 underlying BPES (types 1 and 2) in Colombian families
Authors: Ramírez‐Castro J.L. , Pineda‐Trujillo N. , Valencia A.V. , Muñetón C.M. , Botero O. , Trujillo O. , Vásquez G. , Mora B.E. , Durango N. , Bedoya G. , Ruiz‐Linares A.
Published: October 2002

We report the genetic characterization of one family with blepharophimosis‐ptosis‐epicanthus inversus syndrome (BPES) type 1 and two families with BPES type 2 from a historically isolated population in northwest Colombia. Linkage and haplotype analyses indicate that BPES in these families is linked to 3q23. Mutation screening of FOXL2 in the family with BPES type 1 revealed a novel 394C → T nonsense mutation which deletes the forkhead DNA binding domain. The two families with BPES type 2 both carry an in‐frame 30 bp duplication that leads to the elongation of a polyalanine tract. This duplication has been previously reported in Europe, where recurrent mutation has been demonstrated in unrelated familial and sporadic BPES cases. The recurrent nature of this duplication seems to relate to the secondary structure of this DNA region. The genotype–phenotype correlation seen in the Colombian families is consistent with the recent proposal that BPES type 1 is caused by truncating mutations leading to haploinsufficiency, while BPES type 2 is due to mutations generating elongated protein products. © 2002 Wiley‐Liss, Inc.
Cleft palate, hypotelorism, and hypospadias: Schilbach‐Rott syndrome
Authors: Joss S.K. , Paterson W. , Donaldson M.D.C. , Tolmie J.L.
Published: October 2002

A mother and two sons have cleft palate and facial appearance closely resembling cases described by Schilbach and Rott in 1988. One of the two males has hypospadias and learning disability and, like his mother, is of short stature. The family described by Schilbach and Rott also supports an autosomal dominant inheritance pattern. © 2002 Wiley‐Liss, Inc.
Fibular aplasia with ectrodactyly
Authors: Evans Jane A. , Reed Martin H. , Greenberg Cheryl R.
Published: October 2002

Fibular aplasia with split hand/foot or other defects of the central axis is a rare disorder that shares several characteristics with the better known tibial aplasia‐ectrodactyly syndrome. They appear to be inherited in an autosomal dominant fashion. In both, however, the phenotype is markedly variable, penetrance is reduced, and apparently sporadic cases are relatively frequent. We report a new case of this disorder and review the clinical and demographic findings in 47 others identified from the literature or other sources. A key observation was that the sex ratio is biased toward males, especially in apparently sporadic cases. This male bias is largely explained by a lower penetrance rate in women. Both affected males and females had affected children, but the risk to offspring was higher when the mother carried the gene, in keeping with a mixed model for genetic susceptibility, i.e., the penetrance of the major predisposing gene is acting against a multifactorially determined level of liability. Given the high degree of nonpenetrance and very variable expressivity, counseling with respect to recurrence risk is problematic and will likely remain so, even when the major predisposing gene is identified. © 2002 Wiley‐Liss, Inc.
International nosology and classification of constitutional disorders of bone (2001)
Authors: Hall Christine M.
Published: October 2002

The last International Classification of Constitutional Disorders of Bone was published in 1998. Since then rapid advances have been made in identifying the molecular changes responsible for defined conditions and new disorders are constantly being delineated. For these reasons a further update on the classification is appropriate. It has been expended to not only the osteochondrodysplasias (33 groups) but also genetically determined dysostoses (3 groups). © 2002 Wiley‐Liss, Inc.
Eubaric hyperoxemia and experimental cerebral infarction
Authors: Flynn Erin P. , Auer Roland N.
Published: October 2002

We explore three questions concerning arterial hyperoxygenation and focal ischemia. (1) Does greater benefit accrue with higher levels of arterial hyperoxemia? (2) Is the net effect of continuous (intraischemic plus postischemic) oxygen therapy toxic, or beneficial to middle cerebral artery infarction? (3) In view of free radical theories of reperfusion injury, does hyperoxia isolated to the reperfusion period damage tissue? Rats subjected to transient, focal, normothermic, normoglycemic ischemia were assessed at 2 weeks' survival. Arterial hyperoxygenation from 98.9 ± 4.0 to 312.2 ± 48.4mm Hg during ischemia improved (p < 0.05) neurological function, as did isolated reperfusion hyperoxemia, but treatment with continuous hyperoxemia both during and after ischemia yielded greatest benefit (p < 0.001). Cortical infarcts constituted 6.5 ± 1.8% of the hemisphere at normoxia, but 2.3 ± 0.9% at hyperoxic levels (p < 0.01). Hyperoxia isolated to the reperfusion period also reduced cortical necrosis, from 6.5% to 2.7 ± 1.2%. However, continuous intraischemic and reperfusion hyperoxemia led to only 0.2 ± 0.1% cortical necrosis (p = 0.0005). Increasing the degree of hyperoxemia did not augment the benefit. We conclude that (1) eubaric hyperoxemia improves neurological and neuropathological outcome, (2) continuous oxygen therapy offers the greatest benefit, and (3) reperfusion hyperoxemia is beneficial. The findings should allay clinical concerns regarding oxygen‐induced reperfusion injury, and, by obviating hyperbaric chambers, encourage clinical trials studying arterial hyperoxemia in treating stroke.
Long‐term amygdalohippocampal stimulation for refractory temporal lobe epilepsy
Authors: Vonck Kristl , Boon Paul , Achten Erik , De Reuck Jacques , Caemaert Jacques
Published: October 2002

Short‐term deep brain stimulation (DBS) recently has been shown to be efficacious in refractory temporal lobe epilepsy. We (1) evaluated long‐term DBS in medial temporal lobe structures in patients with normal magnetic resonance imaging (MRI) findings and (2) investigated the use of chronic DBS electrodes for the localization of the ictal onset zone before DBS. In three patients with complex partial seizures (CPSs), DBS electrodes were implanted in the amygdalohippocampal region to identify and subsequently stimulate the ictal onset zone. CPSs were compared before and after chronic DBS. Side effects were carefully monitored. DBS electrodes yielded high‐quality electroencephalogram recordings showing unilateral seizure onset in medial temporal lobe structures. For all patients, unilateral amygdalohippocampal stimulation was performed. After a mean follow‐up of 5 months (range, 3–6 months), all patients had a greater than 50% reduction in seizure frequency. In two patients, antiepileptic drugs could be tapered. None of the patients reported side effects. This open study demonstrates the feasibility of consecutive electroencephalographic recordings and DBS in medial temporal lobe structures using DBS electrodes. These results prompt further studies in a larger patient population to establish the efficacy and safety of chronic DBS as an alternative treatment for refractory temporal lobe epilepsy.
Thalamic neurodegeneration in multiple sclerosis
Authors: Cifelli Alberto , Arridge Marzena , Jezzard Peter , Esiri Margaret M. , Palace Jacqueline , Matthews Paul M.
Published: October 2002

Multiple sclerosis is still regarded primarily as a disease of the white matter. However, recent evidence suggests that there may be significant involvement of gray matter. Here, we have used magnetic resonance imaging and magnetic resonance spectroscopy in vivo and histopathology postmortem to estimate thalamic neuronal loss in patients with multiple sclerosis. Our results show that neuronal loss in multiple sclerosis can be substantial (30–35% reduction). We conclude that a neurodegenerative pathology may make a major contribution to the genesis of symptoms in multiple sclerosis.
The structural consequences of newly diagnosed seizures
Authors: Liu Rebecca S. N. , Lemieux Louis , Bell Gail S. , Sisodiya Sanjay M. , Bartlett Philippa A. , Shorvon Simon D. , Sander Josemir W. A. S. , Duncan John S.
Published: October 2002

Intractable epilepsy may be associated with widespread structural cerebral damage. We determined whether structural damage occurs to the hippocampus, cerebellum and neocortex in the first few years following a diagnosis of seizures. Sixty‐eight patients over the age of 14 years with newly diagnosed seizures and 90 matched controls underwent serial magnetic resonance imaging (MRI) brain scans 3.5 years apart. Using quantitative analysis of serial scans, we determined changes in hippocampal volume, hippocampal T2 relaxometry and total and regional brain volumes. Thirty‐four (50%) patients had recurrent unprovoked seizures between baseline and follow‐up scans. One patient with pre‐existing hippocampal sclerosis (HS) did not develop progressive hippocampal damage. Group analyses found no difference in change in cerebral measures between patients and controls or between patients with and without recurrent seizures. Significant quantitative changes in individuals were largely attributable to pre‐existing cerebral lesions or alcohol abuse. Subtle changes detected in individuals over 3.5 years but were not related to a history of overt seizures. Our results show patients with newly diagnosed seizures are not generally at increased risk of seizure‐induced structural cerebral damage as detected with MRI. Cerebral damage may occur before the onset of seizures or develop insidiously over a more prolonged period.
Herpes vector–mediated expression of proenkephalin reduces bone cancer pain
Authors: Goss James R. , Harley Cara F. , Mata Marina , O'Malley Mark E. , Goins William F. , Hu Xiaoping , Glorioso Joseph C. , Fink David J.
Published: October 2002

We examined whether a herpes simplex virus vector that expresses human proenkephalin could be used to attenuate nociception in a model of bone cancer pain in mice. Osteolytic sarcoma cells were implanted into the medullary space of the right femur, followed by a subcutaneous inoculation of a replication‐defective herpes simplex virus vector expressing human proenkephalin (vector SHPE) or a lacZ‐expressing control vector (vector SHZ). SHPE‐inoculated mice demonstrated a significant, naltrexone‐reversible decrease in pain‐related behavior assessed during open‐field motor activity. These results suggest that gene transfer with an enkephalin‐expressing vector may be used to treat pain resulting from cancer in bone.
A nonsense mutation of the MASS1 gene in a family with febrile and afebrile seizures
Authors: Nakayama Junko , Fu Ying‐Hui , Clark Anna M. , Nakahara Satoko , Hamano Kenzo , Iwasaki Nobuaki , Matsui Akira , Arinami Tadao , Ptác̆ek Louis J.
Published: October 2002

A naturally occurring mutation of the mass1 (monogenic audiogenic seizure‐susceptible) gene recently has been reported in the Frings mouse strain, which is prone to audiogenic seizures. The human orthologous gene, MASS1, was mapped to chromosome 5q14, for which we previously have reported significant evidence of linkage to febrile seizures (FEB4). We screened for MASS1 mutations in individuals from 48 families with familial febrile seizures and found 25 DNA alterations. None of nine missense polymorphic alleles was significantly associated with febrile seizures; however, a nonsense mutation (S2652X) causing a deletion of the C‐terminal 126 amino acid residues was identified in one family with febrile and afebrile seizures. Our results suggest that a loss‐of‐function mutation in MASS1 might be responsible for the seizure phenotypes, though it is not likely that MASS1 contributed to the cause of febrile seizures in most of our families.
Abnormal asymmetry in language association cortex in autism
Authors: Herbert Martha R. , Harris Gordon J. , Adrien Kristen T. , Ziegler David A. , Makris Nikos , Kennedy Dave N. , Lange Nicholas T. , Chabris Chris F. , Bakardjiev Anna , Hodgson James , Takeoka Masanori , Tager‐Flusberg Helen , Caviness Verne S.
Published: October 2002

Autism is a neurodevelopmental disorder affecting cognitive, language, and social functioning. Although language and social communication abnormalities are characteristic, prior structural imaging studies have not examined language‐related cortex in autistic and control subjects. Subjects included 16 boys with autism (aged 7–11 years), with nonverbal IQ greater than 80, and 15 age‐ and handedness‐matched controls. Magnetic resonance brain images were segmented into gray and white matter; cerebral cortex was parcellated into 48 gyral‐based divisions per hemisphere. Asymmetry was assessed a priori in language‐related inferior lateral frontal and posterior superior temporal regions and assessed post hoc in all regions to determine specificity of asymmetry abnormalities. Boys with autism had significant asymmetry reversal in frontal language‐related cortex: 27% larger on the right in autism and 17% larger on the left in controls. Only one additional region had significant asymmetry differences on post hoc analysis: posterior temporal fusiform gyrus (more left‐sided in autism), whereas adjacent fusiform gyrus and temporooccipital inferior temporal gyrus both approached significance (more right‐sided in autism). These inferior temporal regions are involved in visual face processing. In boys with autism, language and social/face processing–related regions displayed abnormal asymmetry. These structural abnormalities may relate to language and social disturbances observed in autism.
p53 inhibitors preserve dopamine neurons and motor function in experimental parkinsonism
Authors: Duan Wenzhen , Zhu Xiaoxiang , Ladenheim Bruce , Yu Qian‐Sheng , Guo Zhihong , Oyler Jon , Cutler Roy G. , Cadet Jean Lud , Greig Nigel H. , Mattson Mark P.
Published: October 2002

Drugs currently used for patients with Parkinson's disease provide temporary relief of symptoms but do not halt or slow the underlying neurodegenerative disease process. Increasing evidence suggests that neurons die in Parkinson's disease by a process called apoptosis, which may be triggered by mitochondrial impairment and oxidative stress. We report that two novel synthetic inhibitors of the tumor suppressor protein p53, pifithrin‐α (PFT‐α) and Z‐1‐117, are highly effective in protecting midbrain dopaminergic neurons and improving behavioral outcome in a mouse model of Parkinson's disease. Mice given intraperitoneal injections of PFT‐α or Z‐1‐117 exhibited improved motor function, reduced damage to nigrostriatal dopaminergic neurons and reduced depletion of dopamine and its metabolites after exposure to the toxin 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP). MPTP caused an increase in the level of the proapoptotic protein Bax, which was prevented by giving mice PFT‐α and Z‐1‐117. PFT‐α and Z‐1‐117 also suppressed Bax production and apoptosis in cultured dopaminergic cells exposed to MPP+. Our findings demonstrate a pivotal role for p53 in experimental parkinsonism and identify a novel class of synthetic p53 inhibitors with clinical potential.
Oligodendrocytic polyglutamine pathology in dentatorubral‐pallidoluysian atrophy
Authors: Yamada Mitsunori , Sato Toshiya , Tsuji Shoji , Takahashi Hitoshi
Published: October 2002

White matter degeneration is one of the pathological conditions of dentatorubral‐pallidoluysian atrophy. Autopsy brains exhibited a reduced number of glial cells in the lesions and an involvement of oligodendrocytes in nuclear inclusion formation, which previously has been recognized only as a pathological hallmark in neurons. Dentatorubral‐pallidoluysian atrophy transgenic mice showed an increased number of affected glias with increasing age and with larger expansions of CAG repeats. These findings suggest that glial cells in dentatorubral‐pallidoluysian atrophy also are involved in the polyglutamine pathogenesis.
Intravenous TAT–Bcl‐Xl is protective after middle cerebral artery occlusion in mice
Authors: Kilic Ertugrul , Dietz Gunnar P. H. , Hermann Dirk M. , Bähr Mathias
Published: October 2002

The delivery of proteins across the blood–brain barrier is severely limited by the proteins' size and biochemical properties. Eleven–amino acid human immunodeficiency virus TAT protein is able to cross cell membranes even when coupled with larger peptides. We evaluated whether TAT–Bcl‐XL fusion protein is protective in focal ischemia. Mice underwent 30 or 90 minutes of intraluminal middle cerebral artery thread occlusion. TAT–Bcl‐XL, TAT–β‐galactosidase, or TAT‐GFP (0.6nmol each) were applied intravenously over 10 minutes either 1 hour before or immediately after ischemia. Additional animals received no TAT protein infusions. We show that the brain tissue is progressively transduced with TAT proteins within 3 to 4 hours after intravenous delivery. We provide evidence that TAT–Bcl‐XL treatment reduces infarct volume and neurological deficits after long ischemic insults lasting 90 minutes, when applied both before and after ischemia. After short insults, lasting only 30 minutes, TAT–Bcl‐XL further diminishes the number of caspase‐3–reactive and DNA fragmented cells and increases the number of viable neurons in the striatum. Our results indicate that TAT fusion proteins are elegant and powerful tools that might be of clinical interest for stroke treatment, because factors may be intravenously applied. Thus, fusion proteins may open fascinating perspectives for future research.
Neuronal and glial metabolite content of the epileptogenic human hippocampus
Authors: Petroff Ognen A. C. , Errante Laura D. , Rothman Douglas L. , Kim Jung H. , Spencer Dennis D.
Published: October 2002

Mesial temporal lobe epilepsy is characterized by hippocampal atrophy, hypometabolism, and decreased N‐acetylaspartate, often attributed to neuron loss and gliosis. Twenty hippocampal specimens were obtained during temporal lobectomy and frozen quickly. Perchloric acid extracts of the small metabolites were analyzed by proton magnetic resonance spectroscopy. There were no significant associations between hippocampal neuron loss and the cellular content of N‐acetylaspartate, glutamate, GABA, glutamine, or aspartate. The mean metabolite content of hippocampi with less than 30% of neurons remaining was the same as those with greater than 65% of neurons surviving. Mean N‐acetylaspartate levels were below those reported by in vivo studies of control subjects. The highest and the lowest glutamate concentrations were seen in specimens with the worst neuron loss. A highly significant association between hippocampal N‐acetylaspartate and glutamate content was seen with weak associations between N‐acetylaspartate and aspartate and glutamate and aspartate. The hippocampal content of N‐acetylaspartate, glutamate, GABA, glutamine, and aspartate is altered minimally by severe neuron loss in mesial temporal lobe epilepsy. The epileptic human hippocampus has increased intracellular glutamate content that may contribute to the epileptogenic nature of hippocampal sclerosis.
Heterozygous GLDC and GCSH gene mutations in transient neonatal hyperglycinemia
Authors: Kure Shigeo , Kojima Kanako , Ichinohe Akiko , Maeda Tomoki , Kalmanchey Rozalia , Fekete György , Berg Suzan Z. , Filiano Jim , Aoki Yoko , Suzuki Yoichi , Izumi Tatsuro , Matsubara Yoichi
Published: October 2002

Transient neonatal hyperglycinemia is clinically or biochemically indistinguishable from nonketotic hyperglycinemia at onset. In the case of transient neonatal hyperglycinemia, the elevated plasma and cerebrospinal fluid glycine levels are normalized within 2 to 8 weeks. To elucidate the pathogenesis of transient neonatal hyperglycinemia, we studied three patients by screening mutations in the genes that encode three components of the glycine cleavage system. Heterozygous mutations were identified in all of the three patients, suggesting that transient neonatal hyperglycinemia develops in some heterozygous carriers for nonketotic hyperglycinemia.
Nonresonant Raman imaging of protein distribution in single human cells
Authors: Uzunbajakava N. , Lenferink A. , Kraan Y. , Willekens B. , Vrensen G. , Greve J. , Otto C.
Published: October 2002

A confocal Raman microscope is used to study the protein distribution inside biological cells. It is shown that high quality Raman imaging of the protein distribution can be obtained using confocal nonresonant Raman imaging (λexc = 647.1 nm). The results are shown for two different human cell types. Perpheral blood lymphocytes are used as an example of the fully maturated cells with a low level of nuclear transcription. Human eye lens epithelial cells are used as an example of cells with a high level of nuclear activity. The protein distribution in both cell types is completely different. The nuclear distribution of the protein largely varies in the peripheral blood lymphocyte cells, while proteins are more homogenously distributed over the nuclear space in the eye lens epithelial cells. The imaging time is ∼20 min for a field of view of 10 × 10 μm2. The size of the sampling volume is 1.4 fL using a full width at half‐maximum criterion along the z axis and a 1/e2 criterion in the xy plane. The results presented here indicate that Raman imaging is particularly of interest in the study of cellular processes, like phagocytosis, apoptosis, chromatin compaction, and cellular differentiation, which are accompanied by relatively large‐scale redistributions of the materials. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 72: 1–9, 2003
Unfolding and pH studies on manganese peroxidase: Role of heme and calcium on secondary structure stability
Authors: Banci Lucia , Bartalesi Ilaria , Ciofi‐Baffoni Simone , Tien Ming
Published: October 2002

The present study characterizes the unfolding and folding processes of recombinant manganese peroxidase. This enzyme contains five disulfide bonds, two calcium ions, and one heme prosthetic group. Circular dichroism in the far UV was used to monitor global changes of the protein secondary structure, whereas UV–visible spectroscopy of the Soret band provided information about local changes in the heme cavity. The effects of reducing agents, oxidizing agents, and denaturants on this process were investigated. In addition to affecting the secondary structure content, these factors also affect the binding of the heme and the calcium ions, both of which have a significant effect on the folding process. Our results also show that denaturants induce irreversible changes, which are most likely due to the inability of the denatured protein to rebind either calcium or the heme. Breaking of disulfide bonds by 30 mM dithiothreitol causes complete unfolding of recombinant manganese peroxidase. The unfolding process was also studied at low and high pH, where the protein reaches the final unfolded state through two different intermediate states. The data also indicate that only the acidic folding–unfolding process is reversible. Our results indicate a complex synergistic relationship between the secondary structure content, the tertiary structure arrangement, and the binding of the heme and the calcium ions and disulfide bridge formation. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 72: 38–47, 2003
Analysis of the role of GADD153 in the control of apoptosis in NS0 myeloma cells
Authors: Lengwehasatit Idsada , Dickson Alan J.
Published: October 2002

Apoptosis can limit the maximum production of recombinant protein expression from cultured mammalian cells. This article focuses on the links between nutrient deprivation, ER perturbation, the regulation of (growth arrest and DNA damage inducible gene 153) GADD153 expression and apoptosis. During batch culture, decreases in glucose and glutamine correlated with an increase in apoptotic cells. This event was paralleled by a simultaneous increase in GADD153 expression. The expression of GADD153 in batch culture was suppressed by the addition of nutrients and with fed‐batch culture the onset of apoptosis was delayed but not completely prevented. In defined stress conditions, glucose deprivation had the greatest effect on cell death when compared to glutamine deprivation or the addition of tunicamycin (an inhibitor of glycosylation), added to generate endoplasmic reticulum stress. However, the contribution of apoptosis to overall cell death (as judged by morphology) was smaller in conditions of glucose deprivation than in glutamine deprivation or tunicamycin treatment. Transient activation of GADD153 expression was found to occur in response to all stresses and occurred prior to detection of the onset of cell death. These results imply that GADD153 expression is either a trigger for apoptosis or offers a valid indicator of the likelihood of cell death arising from stresses of relevance to the bioreactor environment. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 719–730, 2002.
Cumulative bondomers: A new concept in flux analysis from 2D [13C,1H] COSY NMR data
Authors: van Winden Wouter A. , Heijnen Joseph J. , Verheijen Peter J.T.
Published: October 2002

A well‐established way of determining metabolic fluxes is to measure 2D [13C,1H] COSY NMR spectra of components of biomass grown on uniformly 13C‐labeled carbon sources. When using the entire set of measured data to simultaneously determine all fluxes in a proposed metabolic network model, the 13C‐labeling distribution in all measured compounds has to be simulated. This requires very large sets of isotopomer or cumomer balances. This article introduces the new concept of bondomers; entities that only vary in the numbers and positions of C–C bonds that have remained intact since the medium substrate molecule entered the metabolism. Bondomers are shown to have many analogies to isotopomers. One of these is that bondomers can be transformed to cumulative bondomers, just like isotopomers can be transformed to cumomers. Similarly to cumomers, cumulative bondomers allow an analytical solution of the entire set of balances describing a metabolic network. The main difference is that cumulative bondomer models are considerably smaller than corresponding cumomer models. This saves computational time, allows easier identifiability analysis, and yields new insights in the information content of 2D [13C,1H] COSY NMR data. We illustrate the theoretical concepts by means of a realistic example of the glycolytic and pentose phosphate pathways. The combinations of 2D [13C,1H] COSY NMR data that allow identification of all metabolic fluxes in these pathways are analyzed, and it is found that the NMR data contain less information than was previously expected. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 731–745, 2002.
Hydrogen production by cyanobacteria in an automated outdoor photobioreactor under aerobic conditions
Authors: Tsygankov A. A. , Fedorov A. S. , Kosourov S. N. , Rao K. K.
Published: October 2002

The possibility of hydrogen production by a hydrogenase impaired mutant strain of Anabaena variabilis in outdoor culture was studied. A computer‐controlled rooftop (outdoor) tubular photobioreactor (4.35 L) was assembled. H2 production rates by A. variabilis PK84 grown in CO2 + air in the photobioreactor were measured together with other parameters such as temperature, irradiance, pH, dry biomass weight, and pO2, and Chl a concentrations during summer months of 1998 and 1999. Efficiencies of light energy bioconversion to H2 energy and energy accumulated in biomass were calculated. The influence of irradiance, temperature, and mode of cultivation on H2 production and efficiency of light energy bioconversion were evaluated. The culture produced up to 1.1 L H2 day−1 PhBR−1. The efficiency of light energy to H2 energy bioconversion on some days was 0.094%. However, the conditions for maximum H2 photoproduction and for maximum efficiency of light energy to H2 energy bioconversion were not the same. A. variabilis PK84 could produce hydrogen for prolonged periods (up to 40 days) without injection of fresh inoculum. During this period photobioreactor produced 24.5 L of H2. Possibilities for increasing the efficiency of light energy conversion are discussed. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 777–783, 2002.
Characterization of electrostatic binding sites of extracellular polymers by linear programming analysis of titration data
Authors: Liu Hong , Fang Herbert H. P.
Published: October 2002

Electrostatic binding sites of extracellular polymeric substances (EPS) were characterized from titration data using linear programming analysis. Test results for three synthetic solutions of given solutes comprising amino, carboxyl, and phenolic groups indicated that this method was able to identify the electrostatic binding sites. For the six sites with pKa between 3 and 10, the estimated pKa deviated 0.11 ± 0.09 from the theoretical values, and the estimated concentrations deviated 3.0% ± 0.9% from the actual concentrations. Two EPS samples were then extracted from a hydrogen‐producing sludge (HPS) and a sulfate‐reducing biofilm (SRB). Analysis of charge excess data in titration from pH 3 to 11 indicated that the EPS of HPS comprised of five electrostatic binding sites with pKa ranging from 3 to 11. The pKa values of these binding sites and the possible corresponding functional groups were pKa 4.8 (carboxyl), pKa 6.0 (carboxyl/phosphoric), pKa 7.0 (phosphoric), pKa 9.8 (amine/phenolic), and pKa 11.0 (hydroxyl). EPS of the SRB comprised five of similar binding sites (with corresponding pKa values of 4.4, 6.0, 7.4, 9.4, and 11.0), plus one extra site at pKa 8.2, which was likely corresponding to the sulfhydryl group. The total electrostatic binding site concentration of EPS extracted from HPS were 10.88 mmol/g‐EPS, of which the highest concentration was from the site of pKa 11.0. The corresponding values for the EPS extracted from SRB were 16.44 mmol/g‐EPS and pKa 4.4. The total concentrations of electrostatic binding sites found in this study were 20‐ to 30‐fold of those reported for bacterial cell surface, implying that EPS might be more crucial in biosorption of metals than bacterial cell surface in wastewater treatment and in bioremediation. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 806–811, 2002.
Effect of rate of chemical or thermal renaturation on refolding and aggregation of a simple lattice protein
Authors: Nguyen Hung D. , Hall Carol K.
Published: October 2002

We used dynamic Monte Carlo simulation to investigate how changing the rate of chemical or thermal renaturation affects the folding and aggregation behavior of a system of simple, two‐dimensional lattice protein molecules. Four renaturation methods were simulated: infinitely slow cooling; slow but finite cooling; quenching; and pulse renaturation. The infinitely slow cooling method, which is equivalent to dialysis or diafiltration, provides refolding yields that are relatively high and aggregates that are relatively small (mostly dimers or trimers). The slow but finite cooling method, which is equivalent to multiple‐step dilution, provides refolding yields that are almost as high as those observed in the infinitely slow cooling case, but in a relatively short period of time. Quenching, which is equivalent to one‐step dilution or quick quenching, is extremely slow and has low re‐ folding yields. A maximum appears in the refolding yield as a function of denaturant concentration in the simulation but disappears after a very long duration. Finally, the pulse renaturation method provides refolding yields that are substantially higher than those observed in the other three methods, even at high packing fractions. As in the early stages of quenching, there is a maximum in the refolding yield as a function of denaturant concentration when relatively large numbers of denatured chains are added to the refolding solution at each step. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 823–834, 2002.
A fast computational method for computer‐generated Fourier hologram using patch model
Authors: Sakamoto Yuji , Nagao Tomohiro
Published: October 2002

Computer‐generated holography is a technique for displaying a three‐dimensional image from a virtual object inside the computer. It has drawn attention as a display format to satisfy three‐dimensional visual characteristics. However, one problem of the method is the enormous amount of time for calculation of light propagation needed in the generation of holograms. In this paper, as a method of modeling objects, a patch model that defines an object in terms of basic drawings is used. A method is proposed to calculate holograms at high speed from these models. Further, the algorithm is verified by computer simulation. The results of an optical experiment with the hologram fabricated by this proposed method are also reported. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(11): 16–24, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10051
Pulse‐type bursting neuron model using enhancement mode MOSFETs
Authors: Saeki Katsutoshi , Sekine Yoshifumi , Aihara Kazuyuki
Published: October 2002

Recently, research has examined the implementation of brain‐like information processing systems by focusing on the information processing ability of the brains of living organisms, modeling the neural network in the brain, and employing integrated circuit technologies for engineering applications. Since information is transmitted by pulses in the brain, a pulse‐type model that models the actual unmodified pulse waveforms is effective because the basic nature of neurons is considered. Recently, attention has centered on research of models that obtain burst firing that repeats firing and not firing. This research involves both physiological experiments and theoretical models. However, there were few practical models that could be integrated. Previously, the authors proposed a pulse‐type bursting neuron model constructed from depletion‐mode MOSFETs, resistors, and capacitors that could exhibit burst firing. In this paper, we propose a new pulse‐type bursting neuron model corresponding to a modified Bonhoeffer‐van der Pol (BVP) model. This model is constructed only from enhancement‐mode MOSFETs and capacitors that can be applied to the standard method using the CMOS process. First, we explain the theory of our previously proposed pulse‐type bursting neuron model. Then we build a voltage‐controlled negative resistance circuit using the enhancement‐mode MOSFET examined here, and clearly show the changes in the characteristics of the negative resistance by using the voltage of the control terminal as the parameter. We demonstrate that the pulse‐type bursting neuron model corresponding to the modified BVP model can be integrated and implemented. This model can be applied to the standard method using the CMOS process by using this negative resistance circuit, and only enhancement‐mode MOSFETs and capacitors. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(11): 1–7, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10054
Acoustic modeling for speech recognition based on a generalized Laplacian mixture distribution
Authors: Nakamura Atsushi
Published: October 2002

In acoustic modeling for speech recognition, the Gaussian distribution or the Gaussian mixture distribution is widely used. The general reason for preference of the Gaussian distribution in the parametric modeling of an unknown ensemble is the central limit theorem. The Gaussian distribution has many properties that are theoretically clear. For the particular problem, however, in which the time series of an acoustic feature is to be modeled on the basis of a limited number of training samples for speech recognition, there is no guarantee that the method based on the Gaussian distribution is always optimal. Consequently, this paper proposes an acoustic modeling approach based on the generalized Laplacian distribution, which can represent a wider range of distribution shapes, including the Laplacian and Gaussian distributions. The formulation of the generalized Laplacian distribution and the method of estimation of the distribution parameters are described. The acoustic model with the generalized Laplacian mixture output distribution is constructed by retraining of the hidden Markov model with the Gaussian mixture output distribution. It is shown by a continuous speech recognition experiment using natural uttered speech that the recognition performance is improved compared to recognition based on the Gaussian mixture distribution. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(11): 32–42, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10093
A method for detecting fundamental pitch periods of speech utterances using continuity properties of spectral envelopes in the time domain
Authors: Yanagisawa Koichi , Tanaka Kyoko , Yamaura Itsuo
Published: October 2002

In this article, we use the continuity properties of the speech spectral envelope in the time domain to distinguish the true fundamental pitch period (frequency) of an utterance from several candidates for the fundamental period previously obtained by the autocorrelation method, which is itself robust against noise. Because the correlation function is not necessarily a global maximum at the fundamental period due to effects of noise and the like, in using the autocorrelation method, any period at which the correlation function has a maximum must be regarded as a candidate for the fundamental period. In order to distinguish the real period from among these candidates, discrete spectra are generated from the log spectrum by sampling the latter at frequencies that correspond to integer multiples of each candidate fundamental frequency. Each of these discrete spectra then becomes a spectrum envelope candidate. The fundamental period is then determined by using the continuity properties of the shape of the true spectrum envelope in the time domain as criteria. Experimental results indicate that by using this method it is possible to reduce the detection error at a signal‐to‐noise ratio of 0 dB by 5 to 10% compared to ordinary cepstrum and autocorrelation methods under conditions where several kinds of day‐to‐day environmental noise are present. Experiments also confirm that it provides excellent sensitivity in the presence of weak periodic (fan‐motor) noise compared with the autocorrelation method. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(11): 43–55, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10094
A system employing high‐quality speech compression technology to produce voice on demand for visually handicapped persons
Authors: Kaneko Takao , Ohmuro Hitoshi , Mano Kazunori
Published: October 2002

We have developed a voice‐on‐demand system in which a voice reading the latest information such as newspapers and public bulletins or regional information is information‐compressed by a voice coding technique and stored on the disks of a PC server, and then distributed to receivers at the homes of visually handicapped persons via ISDN networks. In the compression of read speech, the low‐rate speech coding technique DualSpeech is developed and introduced. The information content is reduced to about 1/18 with almost no degradation of the quality of the read speech, so that it can be distributed at high speed. Moreover, the one‐megabyte memory embedded in the receiver can store about 60 minutes of the read speech compactly and the stored information content can be retrieved instantly by an index retrieval function. With these merits, the time required in distribution and communication charges are reduced, and a voice‐on‐demand service is realized which has the appeal of allowing repeated listening at any time to information which the visually handicapped persons would like to acquire. Evaluation of the performance of this voice‐on‐demand system indicates that the read speech data can be received in a short time, about 1/8 of the regeneration time, and regenerated speech can be obtained with a high quality equal to that of the personal handy‐phone system (PHS). Moreover, we have performed service experiments using the voice‐on‐demand system employing speech compression for about 50 visually handicapped persons. The following desirable features have become clear from the questionnaire results: enrichment of close‐at‐home information which the visually handicapped persons can select by themselves, increase of the update frequency of the information content, and further enhancement of the operability of the receiver. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(11): 56–70, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10095
A method of preparing thin‐film micro‐PTC thermistors based on BaTiO3 using YAG‐laser irradiation
Authors: Sato Yuichi , Kawamura Toshiaki , Sato Susumu
Published: October 2002

A technique is proposed for obtaining thin‐film positive temperature coefficient (PTC) microthermistors made of BaTiO3‐based material. In this technique, stacked layers of Ti and BaO thin films are irradiated in air by a YAG laser beam, which creates BaTiO3 semiconductor microregions with PTC characteristics. The experiments indicate that by suitably choosing the optical power of the laser beam and its scanning rate over the stacked layers, it is possible, and in fact easy, to control the resistance of the resulting BaTiO3 semiconductor microregions. We found that the resistance of the BaTiO3 semiconductor material created in this way must be sufficiently low in order for the material to exhibit PTC characteristics. In this case, the material becomes a thermistor, that is, its resistance increases rapidly with increasing temperature. As the temperature increases, the resistance suddenly begins to increase starting at a certain threshold temperature. In an attempt to control this threshold temperature, we modified the technique described in this research by replacing some of the Ti sites with Zr. This modified technique led us to conclude that, just as in bulk BaTiO3, such control was indeed possible. When our technique is used, high‐temperature heating of the entire substrate is not necessary, either during the deposition of the thin film or after its deposition. In this way we confirm that it is possible to create compound device modules by fabricating multiple thin‐film microdevices on a single substrate, including PTC microthermistors. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(11): 25–31, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.1113