bluuebunny/crossref_metadata_2025 huggingface dataset:
Antibody convergence along a common idiotypic axis in immunodeficiency virus and hepatitis C virus infections
Authors: Grant Michael D.
Published: August 2002

The anti‐idiotypic antibody 1F7 selectively binds antibodies against human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) gag, pol, and env proteins. We tested anti‐hepatitis C virus (HCV) antibodies to investigate selection of the 1F7 idiotype on antibodies against other chronic pathogens. Twelve of 15 HCV‐seropositive individuals co‐infected with HIV had detectable antibodies against recombinant HCV core, 4 against HCV NS4 protein, and 3 against HCV NS3 protein. All four HCV‐seropositive, non‐HIV‐infected individuals had antibodies against HCV core and NS4, while 3 had antibodies against NS3. The 1F7 idiotype was frequently present on antibodies against each of the HCV antigens in the HIV co‐infected and non‐HIV‐infected groups. Antibodies against HCV, including antibodies recognizing the putative principal neutralizing determinant of HCV E2 protein, displayed skewed κ/λ light chain usage consistent with clonal dominance. These observations extend the association between expression of the 1F7 idiotype and abnormal B cell clonal dominance in HIV and SIV infection to HCV infection and suggest that early establishment of an oligoclonal antibody response against HCV may freeze the B cell repertoire, impair adaptation to emergent HCV variants, and favor escape from neutralizing antibodies. We also demonstrated that expression of the 1F7 idiotype extends beyond antibodies against multiple antigens of AIDS‐causing retroviruses to include antibodies against multiple antigens of an unrelated chronic hepatitis virus. Thus, distinct pathogens establishing chronic infection in the face of strong humoral immune responses select antibodies along a common idiotypic axis of the immune network. J. Med. Virol. 66:13–21, 2002. © 2002 Wiley‐Liss, Inc.
Fatal adult case of severe lymphocytopenia associated with reactivation of human herpesvirus 6
Authors: Yoshikawa Tetsushi , Ihira Masaru , Asano Yoshizo , Tomitaka Akiko , Suzuki Kayoko , Matsunaga Kayoko , Kato Yasuchika , Hiramitsu Sinya , Nagai Tomohito , Tanaka Naoko , Kimura Hiroshi , Nishiyama Yukihiro
Published: August 2002

It has been suggested that immunosuppression associated with human herpesvirus 6 (HHV‐6) infection is a result of functional impairment or direct destruction of immunological cells. The ability of the virus to infect and destroy lymphocytes may cause progressive immunodeficiency in an infant with primary HHV‐6 infection. An adult patient is described who had a fatal cytomegalovirus (CMV) infection due to severe and prolonged lymphocyte depletion associated with HHV‐6 reactivation. The HHV‐6 antibody titers were increased significantly after reactivation, and the virus was isolated from his peripheral blood mononuclear cells. The quantity of both HHV‐6 and CMV DNA was determined by using real‐time PCR in plasma samples collected serially. HHV‐6 DNAemia persisted for 1 month, which started just 1 week after the onset of lymphocytopenia. In contrast to HHV‐6, CMV DNAemia was detected in the terminal phase of the illness. Thus, HHV‐6 reactivation may have been the cause of the severe lymphocyte depletion and fatal CMV infection. J. Med. Virol. 66:82–85, 2002. © 2002 Wiley‐Liss, Inc.
Expression of cytokeratin 16 in human papillomavirus type 11‐infected genital epithelium
Authors: McClowry Tracy L. , Shors Teri , Brown Darron R.
Published: August 2002

During normal keratinocyte differentiation, a coordinated expression of many cytoskeletal and regulatory proteins occurs. Several studies suggest that expression of some of these proteins is altered in epithelium infected by the human papillomavirus (HPV). To examine protein expression, human foreskin tissue was infected with either the low‐risk HPV type 11 or with HPV 83, a high‐risk type. The foreskin tissue was implanted and grown in the athymic mouse xenograft system. Immunohistochemistry and immunoblot analysis of human foreskin xenografts were performed to detect cytokeratin 16 (K16), a protein previously identified in proliferative disorders of the skin. K16 was abundant in HPV 11‐infected xenograft tissue, but was not detected in uninfected or HPV 83‐infected tissue. Analysis of protein extracted from human biopsy tissue demonstrated the same expression patterns in natural infection by HPV 11. Reverse transcriptase PCR detected mRNA transcripts for K16 in both experimental and natural HPV 11‐infected tissues, but not in uninfected tissue. These studies suggest that K16 overexpression during HPV 11‐infection is regulated at the level of transcription. The marked epithelial proliferation that occurs in HPV 11 infection may involve alterations in expression of cytoskeletal proteins, including K16. Determining the mechanisms of K16 transcriptional induction could lead to therapies with the ability to reduce cell proliferation within infected tissue. J. Med. Virol. 66:96–101, 2002. © 2002 Wiley‐Liss, Inc.
Genetic variations of human herpesvirus 7 by analysis of glycoproteins B and H, and R2‐repeat regions
Authors: Thawaranantha Duanthanorm , Chimabutra Kanittha , Balachandra Kruavon , Warachit Paijit , Pantuwatana Somsak , Tanaka‐Taya Keiko , Inagi Reiko , Kurata Takeshi , Yamanishi Koichi
Published: August 2002

Clinical isolates of human herpesvirus 7 (HHV‐7) from the saliva of healthy individual were investigated for genetic variations in the regions of two immediate‐early (IE) genes, the glycoprotein B (gB) and glycoprotein H (gH) genes, and in R2‐repeat. The genomic DNA of 24 isolates from citizens of Thailand, Japan, and the United States was amplified to detect size variations in the IE‐1 and IE‐2 loci, but none was observed, suggesting that there was no deletion or insertion in these genes, in contrast with an IE gene of human herpesvirus 6 (HHV‐6). The sequences of the gB gene from isolates acquired from 5 Japanese and 8 Thai subject were then compared with those of American strains JI and RK with respect to codons that are known to differentiate gB alleles. All the isolates were found to have gB allele C except for the JI strain, which has allele F. Variability was also observed in five specific gH codons, resulting in 6 different groups. The HHV‐7 isolates might be classified into two major genetic variants by combining their gB and gH allelic groupings. In the present study, only JI belonged to variant 1, while the rest of the isolates appeared to belong to variant 2. In the R2‐repeat region, size heterogeneities were observed among the 24 isolates, due to different repeat numbers (17, 15, 14, 13, or 12 repeats). Therefore, we used the R2‐repeat to identify the origins of isolates in a study of HHV‐7 transmission, and found HHV‐7 to be transmitted within a family from both mothers and fathers to their children. J. Med. Virol. 66:370‐377, 2002. © 2002 Wiley‐Liss, Inc.
Minimal reactivation of Kaposi's sarcoma‐associated herpesvirus by corticosteroids in latently infected B cell lines
Authors: Zoeteweij J. Paul , Rinderknecht Andrea S. , Davis David A. , Yarchoan Robert , Blauvelt Andrew
Published: August 2002

Corticosteroid use in transplant recipients increases the incidence and severity of Kaposi's sarcoma (KS), a disease associated with KS‐associated herpesvirus (KSHV) infection. Recently, the prototypic corticosteroid, hydrocortisone, was shown to directly induce lytic cycle reactivation of KSHV in latently‐infected BCBL‐1 cells. The purpose of this study was to examine this phenomenon in further detail. After incubation with dexamethasone (≤ 30 μM) or hydrocortisone (≤ 30 μM) for 1–4 days, we evaluated KSHV reactivation in latently infected B cell lines (BC‐1, BC‐3, and BCBL‐1) by assessing early‐lytic PF‐8 and late‐lytic gpK8.1 protein expression using flow cytometry. Viral particle production was monitored by quantifying KSHV minor capsid protein levels in cell culture supernatants. A small increase in the percentage of cells expressing viral lytic proteins was observed in BCBL‐1, but not in the other cell lines. In combination with 3 nM 12‐O‐tetradecanoyl‐phorbol‐13‐acetate, a known chemical inducer of KSHV replication, corticosteroids (0.3 μM) enhanced KSHV reactivation twofold in some cell lines, but not in others. In all experiments, lytic viral protein expression by flow cytometry correlated with production of viral particles in culture supernatants. In summary, we found that corticosteroids were limited inducers of KSHV reactivation in latently infected cells. Thus, our findings suggest that corticosteroids do not enhance the incidence and severity of KS in transplant recipients by direct cellular effects on KSHV reactivation. J. Med. Virol. 66:378‐383, 2002. © 2002 Wiley‐Liss, Inc.
Importance of C‐terminus of herpes simplex virus type 1 thymidine kinase for maintaining thymidine kinase and acyclovir‐phosphorylation activities
Authors: Saijo Masayuki , Suzutani Tatsuo , Niikura Masahiro , Morikawa Shigeru , Kurane Ichiro
Published: August 2002

We previously isolated an acyclovir (ACV)‐resistant herpes simplex virus type 1 (HSV‐1), strain TAR, from a child with Wiskott‐Aldrich syndrome. An acyclovir‐sensitive HSV‐1, strain TAS, had been isolated from the same patient before the isolation of HSV‐1 TAR. The TK protein of ACV‐sensitive HSV‐1 TAS was composed of 376 amino acids, while that of HSV‐1 TAR was composed of 407 amino acids with altered amino acid residue between positions 355–407. The elongation of TK was caused by a single nucleotide deletion of cytosine from a homopolymer stretch of 4 cytosine residues between positions 1061–1064. There was no viral TK activity in HSV‐1 TAR‐infected Vero cells, indicating the importance of the C‐terminal portion of TK protein from positions 355–376. Recombinant TK polypeptides with amino acid deletions at the C‐terminus were prepared, and TK and ACV‐phosphorylation activities were examined. Deletion of 5 and 6 amino acids from the C‐terminus of the TK polypeptide of HSV‐1 TAS resulted in a reduction of TK activity by approximately 75% and 100%, respectively. These mutant TK polypeptides did not phosphorylate ACV. These results indicate that amino acid residues from positions 371–376 in the C‐terminal portion of HSV‐1 TK protein are essential for keeping TK and ACV‐phosphorylation activities. J. Med. Virol. 66:388‐393, 2002. © 2002 Wiley‐Liss, Inc.
Human herpesvirus 6 variant a infects human term syncytiotrophoblasts in vitro and induces replication of human immunodeficiency virus type 1 in dually infected cells
Authors: Csoma Eszter , Bácsi Attila , Liu Xiangdong , Szabó Judit , Ebbesen Peter , Beck Zoltán , Kónya József , Andirkó István , Nagy Etelka , Tóth Ferenc D.
Published: August 2002

Human herpesvirus 6 (HHV‐6) and human immunodeficiency virus type 1 (HIV‐1) may interact during transplacental transmission of HIV‐1. The placental syncytiotrophoblast layer serves as the first line of defense of the fetus against viruses. Patterns of replication of HHV‐6 variant A (HHV‐6A) and HIV‐1 were analyzed in singly and dually infected human term syncytiotrophoblast cells cultured in vitro. For this purpose, the GS strain of HHV‐6A and the Ba‐L and IIIB strains of HIV‐1 were used. HHV‐6A replication was restricted at the level of early gene products in singly infected syncytiotrophoblasts, whereas no viral protein expression was found in cells infected with HIV‐1 alone. Coinfection of syncytiotrophoblast cells with HHV‐6A and HIV‐1 resulted in production of infectious HIV‐1. In contrast, no enhancement of HHV‐6A expression was observed in cell cultures infected with both viruses. Uninfected syncytiotrophoblast cells were found to express CXCR4 and CCR3 but not CD4 or CCR5 receptors. Infection of syncytiotrophoblasts with HHV‐6A did not induce CD4 expression and had no influence on chemokine receptor expression. Activation of HIV‐1 from latency in coinfected cells was mediated by the immediate‐early (IE)‐A and IE‐B gene products of HHV‐6A. Open reading frames U86 and U89 of the IE‐A region were able to activate HIV‐1 replication in a synergistic manner. The data suggest that in vivo double infection of syncytiotrophoblast cells with HHV‐6A and HIV‐1 could contribute to the transplacental transmission of HIV‐1 but not HHV‐6A. J. Med. Virol. 67:67–87, 2002. © 2002 Wiley‐Liss, Inc.
Glycosaminoglycan‐promoted muscle reinnervation and insulin‐like growth factor‐I levels are affected by anti‐growth hormone‐releasing hormone exposure
Authors: Gorio Alfredo , Citterio Carmen , Muller Eugenio E. , Di Giulio Anna Maria
Published: August 2002

The present study shows that exposure to antibodies to growth hormone‐releasing hormone (GHRH) partially counteracted the promoting effects of treatment with glycosaminoglycans (GAGs) on muscle reinnervation. Sciatic nerve crush was performed in 2‐day‐old rats, and reinnervation of the extensor digitorum longus muscle was monitored. The extent of reinnervation was rather poor in saline‐treated rats, whereas in GAG‐treated rats the extent of muscle reinnervation, the recovery of nerve‐evoked muscle twitch tension, and the number of motor neurons reinnervating the extensor digitorum longus muscle were greatly enhanced. In addition, treatment with glycosaminoglycans increased markedly insulin‐like growth factor‐I (IGF‐I) levels in denervated muscles. Both types of stimulatory action exerted by GAGs were affected by concomitant exposure to anti‐GHRH, with abolition of IGF‐I muscle increase and a smaller enhancement in muscle reinnervation. J Neurosci. Res. 66:1112–1117, 2001. © 2001 Wiley‐Liss, Inc.
Cytokine signaling in the brain: Putting a SOCS in it?
Authors: Wang Jianping , Campbell Iain L.
Published: August 2002

A new family of cytokine‐inducible proteins, termed “suppressors of cytokine signaling” (SOCS), was discovered recently; these proteins function as negative regulators of signaling pathways involved in the cellular actions of many cytokines, growth factors, and hormones. Gene manipulation studies in mice point to the central importance of individual SOCS proteins in maintaining homeostasis by limiting cellular responses to specific cytokines or growth factors in a variety of different physiological systems. Cytokines modulate a wide variety of biological responses in the CNS, so members of the SOCS family might play crucial roles in regulating intracellular signaling by these effectors in both normal and disease states. Although to date studies of the neurobiology of the SOCS family have been limited, we know that many SOCS genes are constitutively expressed in the developing and adult brain, whereas the expression of others, particularly the SOCS1 and SOCS3 genes, can be highly regulated. Furthermore, roles for the SOCS are now evident in the modulation of neuroimmunoendocrine functions affected by a variety of cytokines, including leptin and members of the growth hormone and the interleukin‐6/gp130 superfamilies. Overall, these findings point to the SOCS as likely crucial negative modulators in the temporal and spatial regulation and intensity of cytokine signaling and therefore actions in the CNS. © 2002 Wiley‐Liss, Inc.
Establishment and characterization of immortalized neuronal cell lines derived from the spinal cord of normal and trisomy 16 fetal mice, an animal model of Down syndrome
Authors: Cárdenas Ana María , Allen David D. , Arriagada Christian , Olivares Alexis , Bennett Lori B. , Caviedes Raúl , Dagnino‐Subiabre Alexies , Mendoza Isabel E. , Segura‐Aguilar Juan , Rapoport Stanley I. , Caviedes Pablo
Published: August 2002

We report the establishment of continuously growing cell lines from spinal cords of normal and trisomy 16 fetal mice. We show that both cell lines, named M4b (derived from a normal animal) and MTh (trisomic) possess neurological markers by immunohistochemistry (neuron specific enolase, synaptophysin, microtubule associated protein‐2 [MAP‐2], and choline acetyltransferase) and lack glial traits (glial fibrillary acidic protein and S100). MTh cells were shown to overexpress mRNA of Cu/Zn superoxide dismutase, whose gene is present in autosome 16. We also studied intracellular Ca2+ signals ([Ca2+]i) induced by different agonists in Indo‐1 loaded cells. Basal [Ca2+]i was significantly higher in MTh cells compared to M4b cells. Glutamate (200 μM) and (1S,3R)‐1‐aminocyclopentane‐1,3‐dicarboxylic acid (ACDP) (100 μM) induced rapid, transient increases in [Ca2+]i in M4b and MTh cells, indicating the presence of glutamatergic metabotropic receptors. N‐methyl‐D‐aspartate (NMDA) and kainate, but not alpha‐amino‐hydroxy‐5‐methylisoxazole‐4‐propionic acid (AMPA), produced [Ca2+]i rises in both cell types. MTh cells exhibited faster time‐dependent decay phase kinetics in glutamate‐induced responses compared to M4b cells. Nicotine induced a transient increase in [Ca2+]i in M4b and MTh cells, with significantly greater amplitudes in the latter compared to the former. Further, both cell types responded to noradrenaline. Finally, we examined cholinergic function in both cell lines and found no significant differences in the [3H]‐choline uptake, but fractional acetylcholine release induced by either K+, glutamate or nicotine was significantly higher in MTh cells. These results show that M4b and MTh cells have neuronal characteristics and the MTh line shows differences which could be related to neuronal pathophysiology in Down's syndrome. © 2002 Wiley‐Liss, Inc.
Effects of locally administered pentylenetetrazole on nigral single unit activity and severity of dystonia in a genetic model of paroxysmal dystonia
Authors: Fedrowitz Maren , Hamann Melanie , Rehders Jan H. , Richter Angelika , Gernert Manuela
Published: August 2002

The dtsz hamster is a well‐established animal model of idiopathic paroxysmal dystonia. Previous investigations of this mutant have indicated dysfunctions of the γ‐aminobutyric acid (GABA)‐ergic system within the basal ganglia. Systemic administration of the central stimulant pentylenetetrazole (PTZ) aggravated dystonia at subconvulsant doses, whereas GABA‐mimetic drugs have beneficial effects in dtsz hamsters. GABA mimetics also provide clinical benefit in humans with idiopathic paroxysmal dystonia. The spontaneous discharge rates of substantia nigra pars reticulata (SNr) neurons was unaltered in anesthetized dtsz hamsters, but systemic application of subconvulsant doses of PTZ caused significantly greater increases of discharge rates in dystonic hamsters compared with nondystonic controls. The present study tested the hypothesis that SNr neurons are more sensitive to local application of PTZ in dtsz hamsters than in nondystonic hamsters. PTZ applied locally by pressure injection at 2, 3, and 5 mM to the SNr during in vivo single unit recordings revealed a dose‐dependent increase of SNr discharge rates in mutants and controls relative to predrug rates, with a significantly greater increase in mutants at 3 mM PTZ. To examine the functional relevance of the increased susceptibility of SNr neurons to PTZ in mutants, the effects of PTZ on severity of dystonia were investigated after microinjections into the SNr of freely moving dtsz hamsters. Bilateral nigral microinjection of 40 ng PTZ did not aggravate dystonia but exerted moderate antidystonic effects. Therefore, the previous findings of prodystonic effects of systemic administration of PTZ in dtsz hamsters are related to extranigral effects rather than to the elevation of nigral discharge rates in response to systemic, or locally applied, PTZ. The greater susceptibility of neurons within the SNr to PTZ suggests dysfunctions of the GABAA receptor in dtsz mutants. © 2002 Wiley‐Liss, Inc.
Cell death in the superficial dorsal horn in a model of neuropathic pain
Authors: Whiteside G.T. , Munglani R.
Published: August 2002

The aims of this study were to investigate the occurrence of apoptotic cell death in the dorsal horn of the adult rat spinal cord following chronic constriction injury (CCI) to the sciatic nerve and to correlate this with behavioural responses. Six groups of six rats were used as follows: 1) CCI, 2) CCI, 3) MK801 + CCI, 4) axotomy, 5) sham, and 6) naive. Group 1 animals were behaviourally tested for thermal hyperalgesia 8 days following surgery and sacrificed and the spinal cords removed and frozen. The rest of the groups underwent the same procedure 14 days following surgery. The lumbar region of the spinal cord was cryosectioned and the incidence of apoptotic cells investigated using the TUNEL technique plus Hoechst double labelling. By 8 days post‐CCI, hyperalgesia had developed in the ipsilateral paw, which was still present 14 days after the injury compared to the contralateral paw and naive and sham animals. Preemptive MK‐801 prevented the onset of hyperalgesia. Significant numbers of apoptotic cells were present in the ipsilateral dorsal horn of the spinal cord 8 and 14 days following CCI compared to the contralateral side and to naive and sham animals. Preemptive treatment with MK‐801 reduced the extent of apoptosis resulting from CCI to the level seen in control animals. This study demonstrates that cells undergo apoptosis as a result of CCI simultaneous with the occurrence of hyperalgesia. Furthermore, MK‐801 prevents the onset of hyperalgesia and reduces the extent of apoptotic cell death, suggesting, perhaps, that apoptosis contributes to the initiation/maintenance of hyperalgesia. J. Neurosci. Res. 64:168–173, 2001. © 2001 Wiley‐Liss, Inc.
Expressions of nitrotyrosine and TUNEL immunoreactivities in cultured rat spinal cord neurons after exposure to glutamate, nitric oxide, or peroxynitrite
Authors: Manabe Y. , Wang J.M. , Murakami T. , Warita H. , Hayashi T. , Shoji M. , Abe K.
Published: August 2002

Although excitotoxic and oxidative stress play important roles in spinal neuron death, the exact mechanism is not fully understood. We examined cell damage of primary culture of 11‐day‐old rat spinal cord by addition of glutamate, nitric oxide (NO) or peroxynitrite (PN) with detection of nitrotyrosine (NT) or terminal deoxynucleotidyl transferase‐mediated dUTP‐biotin in situ nick end labeling (TUNEL). With addition of glutamate, NOC18 (a slow NO releaser) or PN, immunoreactivity for NT became stronger in the cytoplasm of large motor neurons in the ventral horn at 6 to 48 hr and positive in the axons of the ventral horn at 24 to 48 hr. TUNEL positive nuclei were found in spinal large motor neurons from 24 hr, and the positive cell number greatly increased at 48 hr in contrast to the vehicle. Pretreatment of cultures with α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionic acid (AMPA)/kainate receptor antagonist, NO‐suppressing agent, and antioxidant protected the immunoreactivity for NT or TUNEL. The present results suggest that both excitotoxic and oxidative stress play an important role in the upregulation of NT nitration and the apoptotic pathway in cultured rat spinal neurons. J. Neurosci. Res. 65:371–377, 2001. © 2001 Wiley‐Liss, Inc.
Differential sensitivity in the survival of oligodendrocyte cell lines to overexpression of myelin proteolipid protein gene products
Authors: Bongarzone Ernesto R. , Jacobs Erin , Schonmann Vilma , Kampf Kathy , Campagnoni Celia W. , Campagnoni Anthony T.
Published: August 2002

The proteolipid (PLP) gene encodes at least four proteins, including the classic PLP and DM20, which are important components of the myelin sheath, and the recently identified soma‐restricted (sr) isoforms, srPLP and srDM20. The classic PLP and DM20 gene products have been implicated in oligodendrocyte survival by overexpression studies in vitro and in vivo. The classic and sr proteolipids are targeted to different cellular compartments in the oligodendrocyte, suggesting different cellular functions. Accordingly, we examined the effects of in vitro overexpression of the sr‐PLP/DM20 isoforms on the survival of stably transfected, conditionally immortalized, oligodendroglial cell lines and compared this to overexpression of the classic and the jimpy‐mutated proteolipids. The results indicate that overexpression of either normal or jimpy classic PLP/DM20 resulted in a dramatic reduction in the survival of the oligodendrocyte cell lines at the nonpermissive temperature, but not the COS‐7 cell line, a cell line expressing the same oncogene constitutively. Survival of the oligodendrocyte cell lines was significantly less affected when either the sr‐PLP/DM20 or the dopamine D‐2 receptor, another cell membrane protein, was overexpressed in the cell lines. These results suggest that overexpression of the “classic” PLP or DM20 can compromise the survival of oligodendrocytes whether or not they are mutated. Furthermore, they suggest that the internal mechanisms for normal targeting of the PLP/DM20 isoforms of either the “classic” or the “sr” types influence the oligodendrocyte's ability to survive when these proteolipids are overexpressed. J. Neurosci. Res. 65:485–492, 2001. © 2001 Wiley‐Liss, Inc.
Role of load bearing in acetylcholinesterase regulation in rat skeletal muscles
Authors: Pregelj Peter , Sketelj Janez
Published: August 2002

Slow antigravity muscles differ from fast muscles with regard to load bearing performed during contraction. We examined the importance of load bearing in regulation of acetylcholinesterase (AChE) expression in slow and fast rat muscles. The levels of AChE mRNA in the slow soleus muscles are about 30% of those in the fast extensor digitorum longus (EDL) muscles. In the soleus muscles unloaded for 8 days by hindlimb suspension, AChE mRNA levels were not significantly different from those in the control soleus muscles. In the suspended animals, AChE transcripts in the EDL muscles decreased to about 80% of control levels. Reduction of the resting muscle tension by joint fixation did not significantly affect the levels of AChE mRNA in the unloaded soleus muscles. Phasic high‐frequency electrical stimulation of the unloaded soleus muscles via the sciatic nerve increased their AChE mRNA levels to about 50% of those in the EDL muscles. The levels observed after phasic stimulation were significantly higher than those after low‐frequency tonic stimulation, indicating the importance of muscle activation pattern for AChE regulation also in the absence of load bearing. The AChE mRNA levels in the soleus muscles overloaded for 8 days by synergist muscle ablation increased significantly to about 50% of those in the EDL muscle. The load bearing during muscle contraction seems to be a relatively unimportant extrinsic factor in the regulation of the AChE mRNA levels in muscle fibers, except when an increased load induces muscle hypertrophy accompanied by the fusion of satellite cells with the muscle fibers. © 2002 Wiley‐Liss, Inc.
New Zealand climate change information derived by multivariate statistical and artificial neural networks approaches
Authors: Mpelasoka F.S. , Mullan A.B. , Heerdegen R.G.
Published: August 2002

Climate change impact assessment requires data at the spatial and the temporal resolution at which impacts occur. The outputs of the current global climate models (GCMs) cannot be used directly in the development of desired climate change scenarios due to their coarse resolution. Artificial neural network (ANN) and multivariate statistics (MST) models were adapted to derive changes of site precipitation and temperature characteristics in a comparative study of their potential in downscaling GCM outputs. They were calibrated and verified using observed site temperature and precipitation over New Zealand and circulation variables from the National Center for Environment Prediction (NCEP) reanalysis.

Subsequently, the models were used to derive changes of mean monthly precipitation and temperature characteristics from circulation variables projected in a transient climate change experiment performed by the Hadley Centre Global Climate Model (HadCM2). HadCM2 validated well with respect to NCEP reanalysis for its ‘present climate’ simulation. The predicted changes in seasonal mean sea level pressure fields over the ‘New Zealand region’ include intensified westerly flow particularly in winter. Therefore, the HadCM2 outputs contain information that can be used to derive localized climate change characteristics.

Both downscaling models capture similar general patterns of change from the same GCM output, although they show substantial differences in localized characteristics, particularly for precipitation. The MST model suggests greater warming than the ANN model but both show larger temperature rises in summer and spring than in other seasons. Precipitation changes have marked spatial variation in their magnitude and direction; although by 2070–2099 more sites show precipitation increases than decreases, except for spring, and precipitation increases are more common in the North Island than the South Island. This intercomparison of two downscaling methods demonstrates an important source of uncertainty in regional climate change scenarios in addition to differing regional responses of GCMs. Copyright © 2001 Royal Meteorological Society
The determination of observed atmospheric differences between heavy and light precipitation events in New Jersey, USA
Authors: Harnack Robert , Apffel Kirk , Georgescu Matei , Baines Shaun
Published: August 2002

The climatology of a limited sample of heavy precipitation events occurring in New Jersey, USA, is studied via statistical averaging and frequency histograms of environmental conditions at the event location. Also, the spatial distribution of related circulation features is examined. In addition, statistical differences between conditions accompanying the heavy (HEAVY) and a selected sample of light (LIGHT) precipitation events is determined. A large number of surface, standard level, stability and wind shear variables are employed as well as synoptic‐scale circulation features. Variables that are identified as statistically significant, after a Student's t‐test is applied to a sample mean and standard deviation are listed by season. In addition, scatter plot and composite maps are produced to illustrate conditions concurrent with the onset of heavy precipitation.

In general, there are only slight differences between values obtained for the HEAVY sample and the LIGHT sample. However, the differences are large enough for some variables in some seasons that the forecaster may be able to use these results to advantage. In particular: (i) a significantly warmer and moister atmosphere at selected levels is indicated for the HEAVY sample for Autumn and Winter but not for Spring and Summer; (ii) upper‐tropospheric divergence is significantly greater in all seasons except Summer; and (iii) wind shear is significantly larger in all seasons except Summer.

There is much similarity in the mean position of examined synoptic features such as troughs, vorticity maxima, jet axes and jet streaks for the two samples. However, the amplitude of circulation in the troposphere is much larger for the HEAVY sample, especially in the lower troposphere. In addition, the 850‐hPa wind maximum axis (low‐level jet indication) is much more often oriented from south to north and located within 300 km of the event location for the HEAVY cases.

There was surprisingly no significant sample difference found for static stability and precipitable water in any season.

Based on the results reported here, the forecaster is particularly advised to examine the tropospheric circulation amplitude and the position of low and upper‐level jet axes and jet streaks before forecasting heavy precipitation in the mid‐Atlantic region of the USA. Copyright © 2001 Royal Meteorological Society
The regional scale impact of land cover change simulated with a climate model
Authors: Zhao Mei , Pitman A. J.
Published: August 2002

A series of 17‐year integrations using the NCAR CCM3 (at about 2.8° × 2.8° resolution) were performed to investigate the regional‐scale impact of land cover change. Our aim was to determine the impact of historical land cover change on the regional‐scale climate over the regions where most change occurred: Europe, India and China. The change from natural to current land cover was estimated using BIOME3 to predict the natural vegetation type, and then using remotely sensed data to estimate the locations where land cover had been changed through human activity. Results show statistically significant changes in the 15‐year averaged 1000 hPa wind field, mean near‐surface air temperature, maximum near‐surface air temperature and the latent heat flux over the regions where land cover change was imposed. These changes disappeared if the land cover over a particular region was omitted, indicating that our results cannot be explained by model variability. An analysis of changes on an averaged monthly time scale showed large changes in the maximum daily temperature in (Northern Hemisphere) summer and little change in the minimum daily temperature, resulting in changes in the diurnal temperature range. The change in the diurnal temperature range could be positive or negative depending on region, time of year and the precise nature of the land cover changes. Our results indicate that the inclusion of land cover change scenarios in simulations of the 20th century may lead to improved results. The impact of land cover changes on regional climates also provides support for the inclusion of land surface models that can represent future land cover changes resulting from an ecological response to natural climate variability or increasing carbon dioxide. Copyright © 2002 Royal Meteorological Society.
Comparison of different earth radiation budget experiment data sets over tropical oceans
Authors: Ho Chang‐Hoi , Chou Ming‐Dah , Sui Chung‐Hsiung
Published: August 2002

We compare radiation budgets derived from different Earth Radiation Budget Experiment (ERBE) archives over the tropical oceans (30S and 30N) from 1985 to 1989. Two ERBE data sets are used. One is taken from the Earth Radiation Budget Satellite (ERBS), and the other from the combined ERBS, National Oceanic and Atmospheric Administration (NOAA) 9, and NOAA 10 satellites. The domain‐mean all‐sky outgoing longwave radiation (OLR) derived from the combined data set shows a notable change in early 1987 when NOAA 10 replaced NOAA 9. This change is also found in longwave (LW) cloud radiative forcing (CRF), all‐sky shortwave (SW) radiation, and SWCRF. The ERBS, however, does not show such changes.

We also examine the sensitivity of cloud–radiation interaction to the sea surface temperature (SST) of the tropical oceans. In general, each component of radiative feedbacks derived from the two ERBE data have the same sign, although they show a certain degree of discrepancy in the magnitude. The discrepancy is more notable for averaged quantities over the entire tropical oceans, particularly over the subtropics where convective activities are relatively weak. The combined data show a larger sensitivity of LWCRF and SWCRF to SST than those of the ERBS, consistent with the above results. The response of clouds to an increase in SST has a net cooling effect when using the combined data but has a net heating effect when using the ERBS data (−0.80 W m−2 K−1 versus 0.48 W m−2 K−1). Most of the discrepancies of the net CRF between the two ERBE data sets can be accounted for by the difference in the sensitivity of all‐sky OLR (4.52 W m−2 K−1 versus 1.73 W m−2 K−1). Copyright © 2002 Royal Meteorological Society.
A high-yield microwave heating method for the preparation of (phthalocyaninato)bis(chloro)silicon(IV)
Authors: DAVIES DOMINIC A. , SCHNIK CHRISTINA , SILVER JACK , SOSA-SANCHEZ JOSE L. , RIBY PHILIP G.
Published: August 2002

The microwave heating synthesis of (phthalocyaninato)bis(chloro)silicon(IV) prepared from diiminoisoindolene and silicon tetrachloride in quinoline has been shown to be rapid (5 min reaction time compared to 30 min with thermal heating) and results in a high yield (91% compared to 71% using thermal heating). A modified microwave ashing furnace was used to heat the reaction mixture. The high yield has led to a reduction in the purification time to 1 h (compared to 4 h or more using conventional heating).
Hydrophilicity vs hydrophobicity — varying the amphiphilic structure of porphyrins related to the photosensitizer m-THPC
Authors: WIEHE ARNO , SIMONENKO EKATERINA J. , SENGE MATHIAS O. , RÖDER BEATE
Published: August 2002

A total of 21 different porphyrins, some of them closely related to the photosensitizer meta-tetrahydroxyphenylchlorin (m-THPC) with a varied degree of hydrophilic/lipophilic substitution were synthesized employing conventional porphyrin condensation procedures and modern functionalization via organolithium reagents. For 14 of them, the photodynamic therapy (PDT) related photophysical properties were determined in isotropic solution and in liposome membrane-model systems. The photophysical data indicate that the localization of m-THPC may be fine-tuned by carefully changing the substitution pattern.
Cold marine indicators of the late Quaternary: the new dinoflagellate cyst genus Islandinium and related morphotypes
Authors: Head Martin J. , Harland Rex , Matthiessen Jens
Published: August 2002

Round, brown, spiny dinoflagellate cysts characterise many modern high‐latitude assemblages. Abundance is often highest where summer sea‐surface temperatures seldom exceed 7 °C and where winter sea‐surface temperatures are around 0 °C, making this morphological group important for reconstructing cold intervals within marine Quaternary sequences. Our analysis of modern sediments from the Beaufort Sea of Arctic Canada, the Kara and Laptev seas of Arctic Russia, and across the Arctic Ocean, allows us to recognise the new cyst genus Islandinium along with the extant species Islandinium minutum (Harland and Reid in Harland et al., 1980) new combination (basionym: Multispinula? minuta), Islandinium? cezare (de Vernal et al., 1989 ex de Vernal in Rochon et al., 1999) new status and combination (basionym: Multispinula? minuta var. cezare) sensu lato, and Echinidinium karaense new species. Of these, the generotype Islandinium minutum is a well‐known but morphologically problematic species. We have re‐examined the type material from the Beaufort Sea and studied specimens from across the Arctic, and our observations clarify ambiguities in the original description of this species. The archeopyle of Islandinium minutum results from the loss of three apical plates, an unusual style among peridiniphycidean dinoflagellates. The asymmetrical location of these plates around the apex is distinctive, and probably contributed to earlier misunderstandings of the archeopyle. Previous attributions to Multispinula? and Algidasphaeridium? are unsustainable. Maps showing the distribution of Islandinium minutum are given for the Northern Hemisphere and show this species to be polar to north‐temperate, whereas Islandinium? cezare s.l. and Echinidinium karaense appear to be more restricted to polar environments. Copyright © 2001 John Wiley & Sons, Ltd.
Changes in the porous silicon structure induced by laser radiation
Authors: Salcedo Walter Jaimes , Ramirez Fernandez Francisco J. , Rubim Joel C.
Published: August 2002

Porous silicon (PS) films were investigated by Raman, and photoluminescence spectroscopies using different laser excitations at 488.0, 514.5, 632.8, and 782.0 nm. The exposure of PS layers to high laser powers causes an increase in the 480 cm−1 Raman intensity and a shift and enhancement of the PL emission. A laser‐assisted surface reaction is proposed to explain these observations. The analysis of the first‐ and second‐order Raman spectra showed that the band gaps of the PS films are indirect as in bulk c‐Si. The Raman phonon and the PL spectra and also the spectral distribution of the linear polarization degree (LPD) of PS layers were shown to be dependent on the laser excitation energy. This dependence cannot be explained within the quantum confinement model. A mechanism for the PL emission in PS layers is presented in which the radioactive recombination of electron–hole pairs occurs in localized centres (the Si—O—SiR moieties) at the pore/crystallite interface. These quasi‐molecular centres are Jahn–Teller active, i.e. the radioactive recombination is a phonon‐assisted phenomenon. Copyright © 2001 John Wiley & Sons, Ltd.
Low‐wavenumber Raman scattering spectroscopy in studies of new gallium‐doped silica glass‐based transparent vitroceramic medium
Authors: Ceccato R. , Maschio R. Dal , Ferrari M. , Gialanella S. , Lipinska‐Kalita K. E. , Mariotto G. , Montagna M. , Ohki Y. , Rossi F.
Published: August 2002

Optically transparent, silica glass‐based vitroceramic material doped with gallium oxide was obtained by standard glass fusion and appropriate thermal treatments. Low‐wavenumber Raman scattering spectroscopy allowed the determination of the microstructure and in particular the size distribution of nanoparticles embedded in the amorphous matrix. The nanocrystal growth was accurately controlled by heat treatment conditions. Transmission electron microscopy and X‐ray diffraction measurements revealed the presence of a single crystalline phase, spherical‐shaped nanoaggregates, homogeneously distributed in the transparent composite medium. Copyright © 2001 John Wiley & Sons, Ltd.
Resonance Raman spectroscopic study of the neutral flavin radical complex of DNA photolyase from Escherichia coli
Authors: Murgida Daniel H. , Schleicher Erik , Bacher Adelbert , Richter Gerald , Hildebrandt Peter
Published: August 2002

The neutral flavin radical complex of DNA photolyase from Escherichia coli was studied by resonance Raman spectroscopy for the first time. The experiments were carried out with enzyme variants that lack the light‐harvesting methenyltetrahydrofolate cofactor so that the resonance Raman spectra exclusively display the vibrational bands of the flavin radical in the catalytic site. Spectral changes induced upon H–D exchange and upon substituting the natural flavin by its 15N‐labelled isotopomer allow a tentative assignment of the prominent bands in the region between 1200 and 1650 cm−1. It is shown that most of the bands observed with 568 nm excitation originate from modes localized in the isoalloxazine ring. In conjunction with previous data on flavin radicals, the present results allow the identification of the marker bands that appear to be particularly sensitive towards changes in the electron density distribution of this ring and, hence, reflect the specific intermolecular interactions in the catalytic site. Copyright © 2001 John Wiley & Sons, Ltd.
In situ Raman monitoring of chromium oxide scale growth for stress determination
Authors: Mougin Julie , Rosman Noël , Lucazeau Guy , Galerie Alain
Published: August 2002

Raman spectra of a growing chromia (Cr2O3) layer generated by oxidation of pure chromium at 750 °C under 150 mbar of oxygen were recorded in situ every 5 min. The wavenumber evolution of the main Raman band versus oxidation time was interpreted in terms of mechanical stress development. Comparison with Raman spectra of a fully relaxed spalled chromia layer submitted to high‐pressure and high‐temperature treatments showed that internal compressive stresses develop during the growth, varying from −2.1 GPa when the scale is very thin to −2.4 GPa when the scale reaches a thickness of 0.6 µm. Relaxation phenomena seem to take place during isothermal oxidation. During cooling, thermal stresses are induced, which are purely elastic according to the perfect reversibility of cooling–heating cycles. Copyright © 2001 John Wiley & Sons, Ltd.
How to determine the pressure of a methane‐containing gas mixture by means of two weak Raman bands, ν3 and 2ν2
Authors: Brunsgaard Hansen S. , Berg R. W. , Stenby E. H.
Published: August 2002

Raman spectra of a pure CH4 sample, two CH4C2 H6 mixtures and a CH4N2 mixture were obtained as a function of pressure at pressures up to 39.6 MPaA (MPa absolute). These spectra are presented in the region 3120–2980 cm−1. A clear pressure dependence of the area ratio between two weak methane bands, ν3 (asymmetric CH stretching) and 2ν2 (overtone of the asymmetric CH bending), is observed; the methane ν3 band intensity is lowered relative to the methane 2ν2 as the pressure is raised. The intensity ratios between these two bands, I(ν3)/I(2ν2), were determined and plotted as a function of pressure. Surprisingly it is observed that the ratio at a fixed pressure is independent of the composition and thereby of the surroundings in which the methane molecule is vibrating. A model function to predict the pressure is given. From a practical point of view, the present results could be useful for determining directly the total pressure in methane mixtures the composition of which is not known. Copyright © 2002 John Wiley & Sons, Ltd.
Raman spectroscopic study of azurite and malachite at 298 and 77 K
Authors: Frost R. L. , Martens W. N. , Rintoul L. , Mahmutagic E. , Kloprogge J. T.
Published: August 2002

Azurite [Cu2+3(CO3)2(OH)2] and malachite [Cu2+2(CO3)(OH)2] are both monoclinic hydroxy carbonates of copper. The Raman spectra of these two minerals were collected at both 298 and 77 K together with the single crystal Raman spectra of azurite at 298 K. The spectra of both azurite and malachite contain modes of three separate vibrational groups: OH, CO3 and Cu O. Accordingly, for azurite the bands at 3453 and 3427 cm−1 have been assigned as the O H stretching mode with the O H bending modes found at 1035 and 952 cm−1. Malachite displays two hydroxyl stretching bands at 3474 and 3404 cm−1 at 298 K which shift to 3470 and 3400 cm−1 at 77 K while O H out‐of‐plane bending modes are found at 1045 and 875 cm−1. For the carbonate group, bands are observed at 1090 cm−1 (ν1), 837 and 817 cm−1 (ν2), 1490 and 1415 cm−1 (ν3) and 769 and 747 cm−1 (ν4). The effect of collecting the spectra at 77 K results in considerable band narrowing. The Raman spectra of the single crystals of azurite show the orientation dependence of the vibrational modes. A mechanism for ν2 splitting is proposed whereby vertical carbonate ions couple to form an in‐phase and out‐of‐phase bending modes. Combination of these vibrational modes such as ν1 + ν3, ν1 + ν3, ν1 + ν4 and 2ν2 are found at 2530, 2414, 1860, and 1670 cm−1, respectively. IR bands for the Cu O stretching modes are observed at 495 and 400 cm−1, while Cu O bending modes occur at 455 and 345 cm−1. Bands at 305 and 240 cm−1 are assigned to the O Cu OH bending modes. The Raman out‐of‐plane bending modes are found at 194 and 170 cm−1. For the carbonate group, infrared bands are observed at 1095 cm−1 (ν1), 834 and 816 cm−1(ν2), 1430 and 1419 cm−1 (ν3) and 764 and 739 cm−1 (ν4). Combination of the CO3 vibrational modes ν1 + ν4 is observed at 1860 cm−1. IR bands for Cu O stretching modes are observed at 580, 570 and 505 cm−1. Copyright © 2002 John Wiley & Sons, Ltd.
The management buy‐out arena: differential slip in a tripartite alliance?
Authors: Contardo Ianna , Angwin Duncan
Published: August 2002

The traditional focus on Management Buy‐Outs (MBOs) has been upon concluding deals. However, substantial numbers of MBOs fail to exit and this paper suggests that the time is ripe for attention to be redirected towards post‐deal evolution.

Three phases in the MBO post‐deal process are identified. These are depicted as The Spirit of Optimism, The Zone of Indifference and The Spiral of Mistrust, reflecting, respectively, the moment of contractual agreement, subsequent stagnation and downward slide in performance.

As the MBO evolves through these phases of decline, this study focuses upon the interactions of three main parties: The Management Team, The Venture Capitalists and The Investment Bankers. The key objective is to capture the difficulties accruing to these parties as the MBO declines.

The failures of the three main parties lie in identities, increasing problems of interaction and lack of communication.

By linking micro, meso and macro levels of analysis a novel way of looking at MBOs is suggested which helps to avoid the trap of focusing only upon the moment the deal is done.

Copyright © 2002 John Wiley & Sons, Ltd.