bluuebunny/crossref_metadata_2025 huggingface dataset:
Type A botulinum neurotoxin proteolytic activity: development of competitive inhibitors and implications for substrate specificity at the S1′ binding subsite
Authors: Schmidt James J. , Stafford Robert G. , Bostian Karen A.
Published: July 2002

Type A botulinum neurotoxin (botox A) is a zinc metalloprotease that cleaves only one peptide bond in the synaptosomal protein, SNAP‐25. Single‐residue changes in a 17‐residue substrate peptide were used to develop the first specific, competitive inhibitors of its proteolytic activity. Substrate analog peptides with P4, P3, P2′ or P3′ cysteine were readily hydrolyzed by the toxin, but those with P1 or P2 cysteine were not cleaved and were inhibitors. Peptides with either d‐ or l‐cysteine as the N‐terminus, followed by the last six residues of the substrate, were the most effective inhibitors, each with a K
i value of 2 μM. Elimination of the cysteine sulfhydryl group yielded much less effective inhibitors, suggesting that inhibition was primarily due to binding of the active‐site zinc by the sulfhydryl group. Botox A displayed an unusual requirement for arginine as the P1′ inhibitor residue, demonstrating that the S1′ binding subsite of botox A is dissimilar to those of most other zinc metalloproteases. This characteristic is an important element in shaping the substrate specificity of botox A.
Expression of type VI adenylyl cyclase in the central nervous system: implication for a potential regulator of multiple signals in different neurotransmitter systems
Authors: Liu Fu-Chin , Wu Gour-Cheng , Hsieh Sung-Tsang , Lai Hsing-Lin , Wang Hsiao-Fang , Wang Tsu-Wei , Chern Yijuang
Published: July 2002

The aim of this study was to investigate the distribution of a calcium‐inhibitable adenylyl cyclase type VI (type VI AC) in the central nervous system using an antiserum directed against the N‐terminus of type VI AC. Our results indicate that type VI AC immunoreactivity is generally expressed in many brain regions with different levels of intensity. Most interestingly, the majority of the detected type VI AC immunoreactivity is present in cells of neuronal phenotype. Double immunostaining of type VI AC and markers of various neurotransmitter systems suggest that type VI AC might participate in regulation of the classical neurotransmitter systems and therefore appeared to play a very important role in the central nervous system.
Cleavage of translation initiation factor 4G (eIF4G) during anti‐Fas IgM‐induced apoptosis does not require signalling through the p38 mitogen‐activated protein (MAP) kinase
Authors: Morley Simon J. , McKendrick Linda , Bushell Martin
Published: July 2002

Initiation factor (eIF) 4G plays a key role in the regulation of translation, acting as a bridge between eIF4E and eIF3, to allow an mRNA molecule to associate with the 40S ribosomal subunit. In this study, we show that activation of the Fas/CD95 receptor complex in Jurkat cells induces the degradation of eIF4G, the inhibition of total protein synthesis and cell death. These responses were prevented by the caspase inhibitors, zVAD.FMK and zDEVD.FMK. We also show that, in contrast to Saccharomyces cerevisiae, although rapamycin caused a modest inhibition of protein synthesis it did not induce apoptosis or the cleavage of eIF4G. Studies with the specific inhibitor, SB203580, have shown that signalling through the p38 MAP kinase pathway is not required for either the Fas/CD95‐induced cleavage of eIF4G or cell death. These data suggest that the cleavage of eIF4G and the inhibition of translation play an integral role in Fas/CD95‐induced cell death in Jurkat cells.
Cell cycle arrest following exposure of EBV‐immortalised B‐cells to gamma irradiation correlates with inhibition of cdk2 activity
Authors: Cannell Emma J , Farrell Paul J , Sinclair Alison J
Published: July 2002

The exposure of Epstein‐Barr virus immortalised B cells (LCLs) to the genotoxic effects of gamma irradiation causes a decreased proliferation of the cells. The early events in this process have been investigated here. The induction of p53 expression correlates with a cell cycle arrest in the G1 and G2/M phases of the cell cycle within 24 h of exposure. The molecular mechanism governing the decreased proliferation appears to involve the induction of the cyclin dependent kinase (cdk) inhibitor p21CIP1 and its functional association with cdk2.
Repression of enzymes of the pentose phosphate pathway by glucose in fission yeast
Authors: Mehta Shwetal , Velmurugan S , Lobo Zita
Published: July 2002

We examine here the effect of carbon sources on the synthesis of the shunt pathway enzymes in the fission yeast Schizosaccharomyces pombe growing on a mixture of ethanol and glycerol. δ‐Gluconolactone induces practically every one of these enzymes. Glucose in contrast tends to attenuate the synthesis of the majority of them. RNA analysis confirms that their induction and repression reflect changes in the levels of their transcripts.
Functional and structural features of γ‐zeathionins, a new class of sodium channel blockers
Authors: Kushmerick Christopher , de Souza Castro Mariana , Santos Cruz Jáder , Bloch Carlos , Beirão Paulo S.L.
Published: July 2002

γ1‐ and γ2‐zeathionins (γ1‐Z and γ2‐Z) are members of a family of small and basic peptides involved in plant protection. These plant defensins exhibit remarkable structural similarity to scorpion neurotoxins and insect defensins. In the present report, we used the whole‐cell patch clamp technique to investigate the inhibition of the sodium current (I
Na) by γ1‐Z and γ2‐Z in the GH3 cell line. Both γ1‐Z and γ2‐Z rapidly and reversibly inhibited I
Na without changing the kinetics or voltage dependence of activation or inactivation. To our knowledge, this is the first example of a plant protein that inhibits the sodium channel. From structural comparisons with the μ‐conotoxins, a family of peptides that block the sodium channel, we detected some similar features that could provide the basis of inhibition of sodium channels by γ‐zeathionins.
A comparative study of the calcium system in memory T cells and naive T cells
Authors: Sigova Alla , Dedkova Elena , Zinchenko Valery , Litvinov Ivan
Published: July 2002

The comparative analysis of responses of memory and naive T lymphocytes to Ca2+‐mobilizing agents, namely Con A, thimerosal, thapsigargin and ionomycin, was carried out. The effect of these agents on both types of T cells differed qualitatively and quantitatively. The lack of intracellular Ca2+ stores in memory T cells was shown. Ca2+‐mobilizing agents did not induce influx of Ca2+ in memory T cells from outside and this was the reason for their stability to Ca2+ ionophores. It was also shown that memory T cells were resistant to the ‘Ca2+ paradox’.
Vitamin B6 biosynthesis: formation of pyridoxine 5′‐phosphate from 4‐(phosphohydroxy)‐l‐threonine and 1‐deoxy‐d‐xylulose‐5‐phosphate by PdxA and PdxJ protein
Authors: Laber Bernd , Maurer Wolfgang , Scharf Sandra , Stepusin Karin , Schmidt Frank S
Published: July 2002

In Escherichia coli the coenzyme pyridoxal 5′‐phosphate (PLP) is synthesised de novo by a pathway that is thought to involve the condensation of 4‐(phosphohydroxy)‐l‐threonine and 1‐deoxy‐d‐xylulose, catalysed by the enzymes PdxA and PdxJ, to form either pyridoxine (vitamin B6) or pyridoxine 5′‐phosphate (PNP). Here we show that incubation of PdxJ with PdxA, 4‐(phosphohydroxy)‐l‐threonine, NAD and 1‐deoxy‐d‐xylulose‐5‐phosphate, but not 1‐deoxy‐d‐xylulose, results in the formation of PNP. The PNP formed was characterised by (i) cochromatography with an authentic standard, (ii) conversion to pyridoxine by alkaline phosphatase treatment, and (iii) UV and fluorescence spectroscopy. Furthermore, when [2‐14C]1‐deoxy‐d‐xylulose‐5‐phosphate was used as a substrate, the radioactivity was incorporated into PNP. These results clarify the previously unknown role of PdxJ in the de novo PLP biosynthetic pathway. The sugar used as substrate by PdxJ is 1‐deoxy‐d‐xylulose‐5‐phosphate rather than the previously assumed 1‐deoxy‐d‐xylulose. The first vitamin B6 vitamer synthesised is PNP, and not pyridoxine.
Rpn4p acts as a transcription factor by binding to PACE, a nonamer box found upstream of 26S proteasomal and other genes in yeast
Authors: Mannhaupt Gertrud , Schnall Ralf , Karpov Vadim , Vetter Irene , Feldmann Horst
Published: July 2002

We identified a new, unique upstream activating sequence (5′‐GGTGGCAAA‐3′) in the promoters of 26 out of the 32 proteasomal yeast genes characterized to date, which we propose to call proteasome‐associated control element. By using the one‐hybrid method, we show that the factor binding to the proteasome‐associated control element is Rpn4p, a protein containing a C2H2‐type finger motif and two acidic domains. Electrophoretic mobility shift assays using proteasome‐associated control element sequences from two regulatory proteasomal genes confirmed specific binding of purified Rpn4p to these sequences. The role of Rpn4p to function as a transregulator in yeast is corroborated by its ability of stimulating proteasome‐associated control element‐driven lacZ expression and by experiments using the RPT4 and RPT6 gene promoters coupled to the bacterial cat gene as a reporter. Additionally, we found the proteasome‐associated control element to occur in a number of promoters to genes which are related to the ubiquitin‐proteasome pathway in yeast.
β2 integrin‐dependent phosphorylation of protein‐tyrosine kinase Pyk2 stimulated by tumor necrosis factor α and fMLP in human neutrophils adherent to fibrinogen
Authors: Yan Sen Rong , Novak M.John
Published: July 2002

Tumor necrosis factor α and fMLP can activate a broad range of cellular functions in neutrophils adherent to biological surfaces. These functions are mediated by integrins and involve the activation of tyrosine kinases. Here, we report that Pyk2, a member of the focal adhesion kinase family, was present in human neutrophils and was rapidly phosphorylated and activated following tumor necrosis factor α and fMLP stimulation in an adhesion‐dependent manner. Tyrosine phosphorylation of Pyk2 was attenuated by β2 integrin blocking with specific antibodies. The tyrosine phosphorylation of Pyk2 was downstream of protein kinases Lyn, Syk and protein kinase C and cytoskeletal organization. The activation of Pyk2 may play a role in adhesion/cytoskeleton‐associated neutrophils function.
Oligonucleotide‐peptide conjugates as potential antisense agents
Authors: Zubin Eugeny M , Romanova Elena A , Volkov Eugeny M , Tashlitsky Vadim N , Korshunova Galina A , Shabarova Zoe A , Oretskaya Tatiana S
Published: July 2002

Oligonucleotide‐peptide conjugates have several applications, including their potential use as improved antisense agents for interfering with the RNA function within cells. In order to provide robust and generally applicable conjugation chemistry, we developed a novel approach of fragment coupling of pre‐synthesized peptides to the 2′‐position of a selected nucleotide within an otherwise protected oligonucleotide chain attached to a solid support.
Activation of src tyrosine kinases by peroxynitrite
Authors: Mallozzi Cinzia , Di Stasi Anna Maria Michela , Minetti Maurizio
Published: July 2002

In this study, we demonstrate that the phosphorylation activity of five tyrosine kinases of the src family from both human erythrocytes (lyn, hck and c‐fgr) and bovine synaptosomes (lyn and fyn) was stimulated by treatment with 30–250 μM peroxynitrite. This effect was not observed with syk, a non‐src family tyrosine kinase. Treatment of kinase immunoprecipitates with 0.01–10 μM peroxynitrite showed that the interaction of these enzymes with the oxidant also activated the src kinases. Higher concentrations of peroxynitrite inhibited the activity of all kinases, indicating enzyme inactivation. The addition of bicarbonate (1.3 mM CO2) did not modify the upregulation of src kinases but significantly protected the kinases against peroxynitrite‐mediated inhibition. Upregulation of src kinase activity by 1 μM peroxynitrite was 3.5–5‐fold in erythrocytes and 1.2–2‐fold in synaptosomes, but this could be the result, at least in part, of the higher basal level of src kinase activity in synaptosomes. Our results indicate that peroxynitrite can upregulate the tyrosine phosphorylation signal through the activation of src kinases.
Interplay of organic and biological chemistry in understanding coenzyme mechanisms: example of thiamin diphosphate‐dependent decarboxylations of 2‐oxo acids
Authors: Jordan Frank
Published: July 2002

With the publication of the three‐dimensional structures of several thiamin diphosphate‐dependent enzymes, the chemical mechanism of their non‐oxidative and oxidative decarboxylation reactions is better understood. Chemical models for these reactions serve a useful purpose to help evaluate the additional catalytic rate acceleration provided by the protein component. The ability to generate, and spectroscopically observe, the two key zwitterionic intermediates invoked in such reactions allowed progress to be made in elucidating the rates and mechanisms of the elementary steps leading to and from these intermediates. The need remains to develop chemical models, which accurately reflect the enzyme‐bound conformation of this coenzyme.
cDNA cloning, characterization and stable expression of novel human brain carboxylesterase
Authors: Mori Mieko , Hosokawa Masakiyo , Ogasawara Yuko , Tsukada Eiko , Chiba Kan
Published: July 2002

The DNA sequence encoding a novel human brain carboxylesterase (CES) has been determined. The protein is predicted to have 567 amino acids, including conserved motifs, such as GEAGG, GXXXXFG, and GDGD which comprise a catalytic triad, and the endoplasmic reticulum retention motif (HXEL‐COOH) observed in CES families. Their gene products exhibited hydrolase activity towards temocapril, p‐nitrophenylacetate and long‐chain acyl‐CoA. Since the molecular masses of these gene products are similar to those that exist in capillary endothelial cells of the human brain [Yamamda et al. (1994) Brain Res. 658, 163–167], these CES isozymes may function as a blood‐brain barrier to protect the central nervous system from ester or amide compounds.
Difference in induction of uncoupling protein genes in adipose tissues between young and old rats during cold exposure
Authors: Yamashita Hitoshi , Sato Yuzo , Mori Nozomu
Published: July 2002

Induction of uncoupling protein (UCP) genes in adipose tissues from young and old rats exposed to cold was compared. UCP1 mRNA expression in brown adipose tissue (BAT) was enhanced in both young and old rats after cold exposure, but the expression was downregulated at 72 h after the exposure only in the young rats. The UCP2 gene was induced notably in BAT of young rats instead of the downregulation of the UCP1 gene, whereas the induction in old rats was almost blunted. The pattern of UCP3 expression was similar to that of UCP1 expression in each group. The effect of cold exposure on the expression of UCP2 genes was also observed in white adipose tissue from the young rats. These results indicate a change in induction of UCP genes in adipose tissues with aging.
Identification of new early markers of the hypersensitive response in Arabidopsis thaliana
Authors: Lacomme Christophe , Roby Dominique
Published: July 2002

New molecular markers of the hypersensitive response (HR) of Arabidopsis thaliana to the bacterial pathogen Xanthomonas campestris pv. campestris (X.c.c..) have been identified by differential screening of a cDNA library constructed from suspension cells inoculated by an HR‐inducing strain in the presence of cycloheximide. Seven families of genes (called Athsr) have been isolated, show similarities to voltage‐dependent anion channels (VDAC) and alternative oxidases, or are novel proteins. Athsr genes have shown to be specifically or preferentially expressed during the HR. These data suggest that Athsr genes might be involved in early events conditioning the establishment of the HR.
Cloning and functional characterization of the human sodium‐dependent vitamin C transporters hSVCT1 and hSVCT2
Authors: Daruwala Rushad , Song Jian , Koh Woo S. , Rumsey Steve C. , Levine Mark
Published: July 2002

Two sodium‐dependent vitamin C transporters, hSVCT1 and hSVCT2, were cloned from a human kidney cDNA library. hSVCT1 had a 1797 bp open reading frame encoding a 598 amino acid polypeptide. The 1953 bp open reading frame of hSVCT2 encoded a 650 amino acid polypeptide. Using a Xenopus laevis oocyte expression system, both transporters were functionally expressed. By Eadie‐Hofstee transformation the apparent K
m of hSVCT1 for ascorbate was 252.0 μM and of hSVCT2 for ascorbate was 21.3 μM. Both transporters were sodium‐dependent and did not transport dehydroascorbic acid. Incubation of oocytes expressing either transporter with phorbol 12‐myristate 13‐acetate (PMA) inhibited ascorbate transport activity. Availability of the human transporter clones may facilitate new strategies for determining vitamin C intake.
The effectiveness of preabortion contraception counseling
Authors: Ortayli N , Bulut A , Nalbant H
Published: July 2002

Objective: To demonstrate the impact of preabortion counseling followed by immediate postabortal provision of the chosen method on postabortion contraceptive use. Methods: Three hundred and forty‐two women undergoing voluntary termination of pregnancy at less than 10 weeks gestation were enrolled at the Woman and Child Health Training and Research Clinic, Medical School of Istanbul. Clinic visits and telephone surveys were performed to measure contraceptive use at 6 months following abortion. Result: Two hundred and thirty‐six women either visited the clinic or responded to the telephone survey. Eighty percent of the respondents reported use of a modern contraceptive as compared to less than 40% prevalence found in the national survey. Conclusion: Preabortion counseling combined with immediate postabortal provision of contraceptives may significantly increase contraceptive use at 6 months postprocedure.
A study of intravaginal misoprostol for induction of labor in toxemia of pregnancy
Authors: Sahin H.G. , Sahin H.A. , Surucu R. , Guvercinci M.
Published: July 2002

Objective: To compare the efficacy and complications of intravaginal misoprostol for induction of labor in patients with and without toxemia of pregnancy. Methods: Forty‐two patients with toxemia of pregnancy (group 1) and 59 women at term without toxemia (group 2) with Bishop scores of ≤6 were treated with 50 μg intravaginal misoprostol given four times at 4‐h intervals. Labor and neonatal outcomes, and any complications, were recorded. Mann–Whitney U‐, Student's t‐ and χ2‐tests were used for statistical analyses. P≤0.05 was considered significant. Results: The rates of vaginal delivery were 73.8% and 84.6%, oxytocin augmentation were 4.8% and 5.1% and the mean insertion to delivery times were 12.5 and 13.8 h in group 1 and 2, respectively, with no significant differences between the groups. Neonatal outcomes, rates of uterine contraction abnormalities and gastrointestinal symptoms were similar in both groups. Conclusions: Intravaginal misoprostol is an equally effective and safe method of induction of labor in patients with toxemia of pregnancy and in normal pregnant women.
FIGO society survey: acceptance and use of new ethical guidelines regarding induced abortion for non‐medical reasons
Authors: McKay H.E , Rogo K.O , Dixon D.B
Published: July 2002

Objective: FIGO's Ethical guidelines regarding induced abortion for non‐medical reasons offer guidance concerning women's right to safe abortion services and the medical community's attendant responsibilities. Ipas surveyed FIGO constituent societies to determine their agreement with the Guidelines’ recommendations and their readiness to use them to improve and expand services. Method: Ten months after the Guidelines publication in IJGO, a ten‐item questionnaire was mailed to 283 Officers of the 101 FIGO societies, with follow‐up prompts to non‐respondents. Results: Officers of 59 societies responded, divided evenly between those in countries whose laws permit induced abortion on non‐medical grounds and those in countries prohibiting it. In ‘permitting’ countries all responding societies supported the recommendations, and 85% said they should adopt them or had already done so. Two‐thirds in ‘prohibiting’ countries supported the recommendations, but less than half believed their FIGO society, or their government, should adopt them. However, 20% in the ‘prohibiting’ countries had adopted or formally considered the recommendations and 23% had already brought them to the attention of their governments. Conclusion: The FIGO constituent societies showed overall strong support for the recommendations, but efforts need to be made to encourage those in ‘prohibiting’ countries to promote implementation of the recommendations.
Laparoscopic total abdominal hysterectomy by suturing technique, with no transvaginal surgical approach: a review of 276 cases
Authors: Ostrzenski A.
Published: July 2002

Objective: To determine the effectiveness and safety of the new technique of laparoscopic total abdominal hysterectomy with prophylactic retroperitoneal rectovaginal‐pouch of Douglas reconstruction and vaginal vault re‐suspension by suturing method, with no transvaginal surgical approach. Methods: The clinical prospective study included 276 women, and was conducted from July 1990 through December 1995. All women were subjected to a laparoscopic total abdominal hysterectomy with prophylactic retroperitoneal rectovaginal and pouch of Douglas reconstruction and vaginal vault suspension. The entire operation was executed via laparoscope with suturing and tying of extracorporeal sliding and intracorporeal two‐turn flat square knot technique, and no transvaginal surgery was performed. The criteria for postoperative early (within 5 h) discharge plan were designed and assessed. Results: All pre‐planned instances of laparoscopic total abdominal hysterectomy with prophylactic retroperitoneal rectovaginal‐pouch of Douglas reconstruction and vaginal vault re‐suspension were completed; no technique failure was encountered. The average operating time for both hysterectomy and prophylactic surgery was 192 min. Intraoperative complications were two bladder injuries (0.72%); one case of inferior epigastric vessels injury (0.36%); one case of autologous, cells saver processed blood transfusion (0.36%). The immediate postoperative complications were four cases of voiding difficulty (1.45%) and five patients experiencing post anesthesia inordinate nausea and vomiting (1.81%). One patient required postoperative blood transfusion (0.36%). Delayed postoperative complications included 2 patients (0.72%) with superficial incisional skin infection. Estimated hemoglobin loss was from 0.5 g/dl to 5.0 g/dl, mean loss 1.5 g/dl. The extirpated uterine average weight 163 g. Postoperatively, within 24 h, 265 patients (96.01%) out of 276 were discharged home on the day of surgery, within 5 h, 110 patients (41.51%) out of 265 left the surgical unit. There was no single hospital post surgical re‐admission. Conclusions: Laparoscopic total abdominal hysterectomy with prophylactic retroperitoneal rectovaginal‐pouch of Douglas reconstruction and vaginal vault suspension by suturing method is a safe, well‐defined operation, executed with no need for transvaginal surgical approach, and well accepted by patients.
Digital examination and transperineal ultrasonographic measurement of cervical length to assess risk of preterm delivery
Authors: Önderoğlu L.S
Published: July 2002

Objective: To compare the diagnostic performance of cervical length measurement determined with transperineal ultrasonography and digital assessment of the cervix for the prediction of preterm delivery in patients with preterm labor. Method: 90 patients admitted to the hospital with the diagnosis of preterm labor and intact membrane underwent cervical length measurement by transperineal ultrasonography along with digital examination for cervical dilatation and effacement. The main outcome measure was delivery before 37 weeks' gestation. Results: 32 patients (35.5%) delivered preterm. Receiver operative characteristic curve analysis revealed that cervical canal length ≤28 mm measured by transperineal sonography had the highest diagnostic performance with a sensitivity of 78.1% and specificity of 82.7%. The sensitivity and specificity of digital examination were found to be 65.5%, 72.4% and 62.5%, 68.9% for the cervical dilatation>2 cm and effacement≥40%, respectively. Conclusion: Transperineal ultrasonographic examination for cervical length is more accurate than digital examination for prediction of preterm delivery in patients presenting with preterm labor. Transperineal ultrasonographic examination of cervix is invaluable in the prediction of preterm delivery where transvaginal transducers are lacking or skilled staff are unavailable.
Fetal blood flow redistribution in term intrauterine growth retardation (IUGR) and post‐natal growth
Authors: Yoshimura S. , Masuzaki H. , Miura K. , Gotoh H. , Ishimaru T.
Published: July 2002

Objective: The purpose of the present study was to evaluate the relationship between intrauterine growth retardation, represented by fetal blood flow redistribution and infantile growth. Methods: The blood flow velocity waveform of umbilical and middle cerebral arteries was recorded by Doppler ultrasonography in 77 growth‐retarded fetuses. We recorded the pulsatility index (PI) of the umbilical artery and middle cerebral and calculated the PI ratio of the middle cerebral to umbilical artery (C/U ratio). We selected a cutoff value of 1.0 to distinguish between normal and abnormal C/U ratios. To evaluate the development of infants, height, body weight and head circumference were measured serially at 3, 6 and 12 months of age. Results: Birth weight was significantly lower in newborns who had abnormal C/U ratios (2021 ± 295 g vs. 2294 ± 236 g). The number of cases admitted to NICU was higher and the duration of admission was longer in abnormal C/U ratio group (15/29 and 33.7 ± 13.5 days) than normal C/U ratio group (7/48 and 26.6 ± 5.6 days). Body weight was lower in infants of abnormal C/U ratio group at 3 months, but was not different at 6 and 12 months. The height was shorter in abnormal C/U ratio group at birth, there were no significant differences at 3, 6 and 12 months. The number of newborn infants with growth retardation was slightly higher in abnormal C/U ratio group, but the difference was not significant at 6 and 12 months. There was no relationship between C/U and growth variables recorded at birth and follow‐up in infants. Conclusion: Intrauterine growth‐retardation, represented by abnormal fetal blood redistribution was associated with adverse perinatal outcome, but the influence was not found at the first year of life.
Collaboration between industry and academia — prospects for male fertility control
Authors: Stock G. , Habenicht U.‐F.
Published: July 2002

Drug development within the pharmaceutical industry is probably the field with the highest level of regulations. Due to the complexity of the different components of drug development and drug surveillance the need for a sophisticated organization and infrastructure is obvious. In addition, there is a necessity for sufficient resources and long‐term commitment as well as logistic and long‐term knowledge management. In order to secure high professional standards at all levels of this highly complex value creating chain, the number of cooperative arrangements in the pharmaceutical industry are increasing. The identification of new targets in the drug finding process calls in particular for outside partners. At the same time the preparedness of non‐industrial researchers to cooperate with industry has also increased significantly. The area of fertility control, especially male fertility control, provides an excellent example for this kind of cooperation between industrial and non‐industrial partners. Here a cooperative network is described which probably meets practically all relevant criteria for both the non‐industrial but also the industrial partner. Some principles for the management of such a cooperative network are discussed. We believe that this kind of network can serve as a model for similar networks in other fields.
The past, present and future
Authors: Diczfalusy E.
Published: July 2002

My generation has seen more progress in science and technology than all preceding generations together. We have also witnessed several intellectual, technological, medical and social revolutions spearheaded by the contraceptive revolution and followed by those in reproductive health, gender equity, information, communication, globalization, international assistance, etc. The results of the first contraceptive revolution were spectacular, by 1990 some 900 million couples used contraception, which became a global lifestyle. When this revolution lost momentum, a new departure took place: the Rockefeller Foundation's Contraception‐21 initiative. The major achievements of this initiative are presented in this volume. All papers represent a significant contribution also to the ultimate objective: the achievement of human dignity for every woman. The revolutions mentioned above profoundly changed the world and our perception of it. They will also assist humankind in deconstructing the deterministic worldview of past centuries and replacing it with a science‐driven anthropocentric philosophy.
Intrapartum fetal distress and magnesium sulfate
Authors: Vigil‐De Gracia P , Simitı́ E , Lora Y
Published: July 2002

Objective: Intrapartum fetal distress is an obstetric emergency traditionally managed by immediate delivery by either the vaginal route or cesarean section. However, there is usually time to attempt intrauterine resuscitation. The purpose of this study was to report the utilization of magnesium sulfate for intrauterine resuscitation. Method: Twenty‐one fetuses received magnesium sulfate 4‐g intravenous bolus in mothers awaiting cesarean section for fetal distress in the labor room of the Complejo Hospitalario Metropolitano de la Caja de Seguro Social de Panamá, from March through August 1997. Fetal distress in labor was defined as the presence of repetitive late decelerations, persistent loss of baseline variability, severe variable decelerations, or bradycardia. Results: Twenty‐one fetuses received magnesium sulfate 4‐g intravenous bolus in mothers awaiting cesarean section for fetal distress. Uterine activity ceased in seven patients, diminished in 13 patients and did not change in one. In all cases, but one, there was recovery of the FHR within 4 min; furthermore there was rose reactive of FHR in nine patients. The 1‐min Apgar scores were 7 or above in 18 cases and the 5‐min Apgar scores were 7 or above in 20 patients. Conclusions: In summary, magnesium sulfate may be useful in the management of acute intrapartum fetal distress when there is evidence of increased uterine activity.
Leishmania major: Cell type dependent distribution of a 43 kDa antigen related to silent information regulatory‐2 protein family
Authors: Zemzoumi Khalid , Sereno Denis , Francois Céline , Guilvard Eliane , Lemesre Jean‐Loup , Oualssi Ali
Published: July 2002

In previous studies we have characterized several Leishmania major polypeptides and showed that one member of this group (LmSIR2rp) shared significant homology to silent information regulator 2 (SIR2) of Saccharomyces cerevisiae, a protein playing a role in both telomeric and mating type loci repression in these organisms. In the present study, by using molecular and immunological approaches, we could identify LmSIR2rp homologues in different Leishmania species and developmental stages (eg logarithmic (LP) and stationary phase promastigotes (SP) and amastigotes). The reactive antigen was also detected in Trypanosoma cruzi extracts. Surprisingly, immunofluorescence assays revealed that LmSIR2rp is associated mainly with cytoplasmic granules of different sizes and numbers depending on the life stage of the parasite used. No reactivity was observed in the nucleus, in agreement with the Western blot showing an absence of immunoreactivity of anti‐LmSIR2rp immune serum against parasite nuclear extracts. Furthermore, immunoprecipitation of [35S]methionine‐labeled promastigote antigens after pulse chase experiments, using anti‐LmSIR2rp fusion protein antibodies, showed that the protein is among parasite excreted‐secreted antigens (ESA). Moreover, immunoflurescence assays conducted with short time incubations of either purified LmSIR2rp or viable promastigotes with murine macrophages, revealed that LmSIR2rp could be bound to the macrophage surface. The unexpected cytoplasmic localization of LmSIR2rp and its presence in ESA may suggest a new mode of action for silent information regulatory factor homologues.
Depletion of cortical target induced by prenatal ionizing irradiation: effects on the lateral geniculate nucleus and on the retinofugal pathways
Authors: Schmidt Sergio L. , Vitral Renan W.F. , Linden Rafael
Published: July 2002

Studies using neonatal surgical lesions to reduce the target area of the retina have supported the idea that developing axons show only a limited specificity in their targeting. This investigation tested whether retinogeniculate axons adjust for partial target depletion by repositioning of axons. We used adult Swiss mice exposed to γ rays at the time when layer IV cells are generated in the ventricular zone (16 days of gestation). Nissl‐stained brain sections were used for histological analyses in thalamus and cortex. Retinal ganglion cells were backfilled from the optic tract with horseradish peroxidase. Intraocular injections of horseradish peroxidase were used to study the retinal projections. In the posterior cortex there was a nearly complete absence of layer IV. The irradiated animals showed a 75% reduction of the dorsal lateral geniculate nucleus. The ventral division, superior colliculus, and other visually related nuclei were not affected. The loss in the ganglion cells (15.7%) was significant but clearly smaller than that observed in the dorsal lateral geniculate nucleus (75%). Therefore, the shrinkage of the dorsal lateral geniculate nucleus led to a reduction in the area available for retinal projections. Despite partial target loss, pattern of retinal projections did not differ from that of the controls. The effect on the dorsal lateral geniculate nucleus is discussed in the light of differences between prenatal and neonatal damage of the presumptive visual cortex. The absence of aberrant retinal projections suggests that repositioning of axons is not the first mechanism employed by retinal axons to match connections in numerically disparate populations.
Disturbance of neuronal plasticity is a critical pathogenetic event in Alzheimer's disease
Authors: Arendt Thomas
Published: July 2002

Brain areas affected by AD pathology are primarily those structures that are invovled in the regulation of “higher brain functions”. The functions these areas subserve such as learning, memory, perception, self‐awareness, and consciousness require a life‐long re‐fittng of synaptic contacts that allows for the acquistion of new epigenetic information, a process based on a particularly high degree of structural plasticity. Here, we outline a hypothesis that it is the “labile state fo differentiation” of a subset of neurons in the adult brain that allows for ongoing neuroplastic processes after development is completed but at the same time renders these neurons particularly vulnerable. Mechanisms of molecular and cellular control of neuronal differentiation and proliferation might, thus, not only play a role during development but critically involved in the pathogenesis of neurodegeneration.
Time course of the effects of prenatal gamma irradiation on the dorsal lateral geniculate nucleus of Swiss mice
Authors: Abreu‐Villaça Yael , Schanuel Sheine Menezes , Schmidt Sergio Luis
Published: July 2002

A previous study reported that adult mice irradiated at the 16th embryonic day present a severe neuronal number reduction in the dorsal lateral geniculate thalamic nucleus. In the present study, we investigated the time course of the effects of prenatal irradiation on this thalamic nucleus. One day after irradiation, a great number of pyknotic figures were seen mainly in the cerebral proliferative zones. In the geniculate nucleus, only scattered pyknotic figures were identified. On the first week after birth, the geniculate nucleus presented frequent pyknotic figures. From five days after birth onwards, a severe shrinkage of the occipital cortex and a great reduction in the geniculate nucleus neuronal number were found. On the second week after birth this neuronal number reduction reached as high as 75%. At each postnatal analyzed age, severe volumetric geniculate nucleus shrinkage was combined to non‐significant neuronal density variations. The presence of few pyknotic figures in the geniculate nucleus one day after irradiation and its delayed neuronal loss indicate an indirect effect of irradiation. We suggest that the effect upon the geniculate nucleus is secondary to the damage of the occipital cortex. A possible interpretation for thalamic neuronal loss is that geniculate neurons fail to establish cortical arbors after major target loss. In this case, the loss of trophic support should also be considered.
Development and maturation of noradrenaline‐containing nerves of the rat uterine artery. Effects of acute and chronic oestrogen treatment.
Authors: Corbacho A.M. , Brauer M.M. , Pérez T.
Published: July 2002

The development and maturation of noradrenaline‐containing nerves of the rat uterine artery was investigated, histochemically and biochemically, at seven different postnatal age‐stages and following acute and chronic treatment with oestradiol. Morphological changes in the vessel were quantitatively evaluated on toluidine blue‐stained semithin sections and low magnification electronmicrographs. In summary, the uterine artery is innervated at birth; the adult pattern of innervation is established at two weeks of age; the innervation density increases progressively between the infantile and prepubertal periods, accompanying proliferation and growth of smooth muscle cells in the tunica media; changes in the innervation are followed by an increase in the tissue concentration of noradrenaline and neither the endocrine changes characterizing puberty nor acute or chronic treatment with oestradiol have an effect on the pattern of development of the uterine artery and associated noradrenaline‐containing nerves. Results are interpreted considering the differential susceptibility of urinogenital organs to sex hormones.
Identifying the G protein, Gzα, and its associated proteins in nervous tissue using mass spectrometry and microsequencing techniques
Authors: Bartlett Selena E. , Hendry Ian A.
Published: July 2002

The signalling pathway associated with pertussis and cholera toxin sensitive G proteins have been extensively investigated. In contrast, the function and associated signal transduction cascade for the pertussis toxin insensitive G protein, Gzα, has remained elusive. Therefore, the aim of this study was to identify the signal transduction pathway associated with Gzα by using the protein identification techniques of matrix assisted laser desorption ionization‐time of flight mass spectroscopy and N‐terminal Edman sequencing. We have chosen this technique to identify proteins that Gzα associates with and to gain insights into the potential role this G protein plays in cells. As Gzα is predominantly localized in neuronal tissues, homogenates of whole brain tissue were used. Gzα and its associated proteins were immunoprecipitated from brain tissue and identified. The immunoprecipitation of four proteins (140, 46, 41 and 36 kDa) was shown to be inhibited in the presence of the Gzα peptide. These proteins were subsequently identified as phospholipase C (PLC)‐γ, β or γ‐actin, Gzα and Gβ, the β subunit of heterotrimeric G proteins, respectively. These results suggest that Gzα exists in a protein complex with the actin cytoskeleton and an important intracellular signalling enzyme, PLC‐γ. These methods are powerful techniques for determining protein–protein interactions, and provides the first step to the identification of signalling proteins that Gzα associates with. However further experimentation will be required to determine the biological relevance of these protein interactions.
Temporal pattern of plasminogen activator activity in the developing chick cerebellum
Authors: Scicolone G. , Pereyra‐Alfonso S. , Sanchez V. , Flores V.
Published: July 2002

Plasminogen activators are considered to be involved in several developmental events. The present work aims at characterizing the developmental pattern of expression of plasminogen activators in the chick cerebellum.

Soluble fractions derived by ultracentrifugation from Triton X‐100 treated membrane fractions were used for determination of the enzyme activity with a radial fibrinolytic assay. By using specific inhibitors and different anti‐plasminogen activators antibodies it is shown that only one type of the enzyme, the urokinase‐type plasminogen activator, is expressed during the cerebellum ontogeny. Our results show the existence of a bimodal pattern of enzyme activity with two peaks that temporally coincide with the processes of massive neuronal migration, neurite outgrowth and synapse formation and plasticity. It is proposed that plasminogen activator could play a role in these developmental events and that its pattern of variability is developmentally regulated.
Expression of the low affinity neurotrophin receptor, P75NGFR, in the rat forebrain, following unilateral bulbectomy
Authors: Turner Christopher P. , Perez‐polo J.Regino
Published: July 2002

It has been hypothesized that the main olfactory bulb, with its relatively rich source of neurotrophins, may provide trophic support for neurons that project to the bulb. We monitored expression of the common, low affinity receptor for neurotrophins, p75NGFR, in the olfactory bulb and basal forebrain of unilaterally bulbectomized and sham‐treated rats, 1–16 weeks post‐surgery, using the monoclonal antibody MAb192. An induction of p75NGFR‐immunoreactivity was observed in both the glomerular and olfactory nerve layers of the right, contralateral main olfactory bulb of lesioned animals. The naturally occurring regeneration taking place in the olfactory neuroepithelium is known to be altered by olfactory bulbectomy, with subsequent changes in the sensory input to the remaining bulb. These changes in expression of p75NGFR in the olfactory bulb support the hypothesis we have developed in previous papers, that changes in the extent of the peripheral input from the olfactory neuroepithelium to the main olfactory bulb regulate p75NGFR expression in both the glomerular and the olfactory nerve layers. Expression of p75NGFR in the basal forebrain of bulbectomized animals was found to be no different than sham‐treated controls and does not support the hypothesis that the olfactory bulb provides trophic support to this region of the central nervous system.
Stress and the adaptive self‐organization of neuronal connectivity during early childhood
Authors: Huether Gerald
Published: July 2002

A conceptual framework is proposed for a better understanding of the biological role of the stress‐response and the relationship between stress and brain development. According to this concept environmental stimuli (in children mainly psychosocial challenges and demands) exert profound effects on neuronal connectivity through repeated or long‐lasting changes in the release of especially such transmitters and hormones which contribute, as trophic, organizing signals, to the stabilization or destabilization of neuronal networks in the developing brain. The increased release of noradrenaline associated with the repeated short‐lasting activation of the central stress‐responsive systems in the course of the stress‐reaction‐process to psychosocial challenges which are felt to be controllable acts as a trigger for the stabilization and facilitation of those synaptic and neuronal pathways which are activated in the course of the cognitive, behavioral and emotional response to such stressors. The long‐lasting activation of the central stress‐responsive systems elicited by uncontrollable psychosocial conflicts in conjunction with the activation of glucocorticoid receptors by the sustained elevation of circulating glucocorticoid levels favors the destabilization of already established synaptic connections and neuronal pathways in associative cortical and limbic brain structures. The facilitation and stabilization of neuronal pathways triggered by the experience of controllable stress is thus opposed, attenuated or even reversed in the course of long‐lasting uncontrollable stress. This destabilization of previously established synaptic connections and neuronal pathways in cortical and limbic brain structures is a prerequisite for the acquisition of novel patterns of appraisal and coping and for the reorganization of the neuronal connectivity in the developing brain. Alternating experiences of repeated controllable stress and of long‐lasting uncontrollable stress are therefore needed for the self‐adjustment of neuronal connectivity and information processing the developing brain to changing environmental (psychosocial) demands during childhood. The brain structures and neuronal circuits involved in the regulation of behavioral responding become thus repeatedly reoptimized and refitted, not the changing conditions of life per se but rather to those conditions which are still able to activate the central stress responsive systems of an individual at a certain developmental stage.
Emigration of neuroepithelial cells from the hindbrain neural tube in the chick embryo
Authors: Sohal G.S. , Ali M.M. , Galileo D.S. , Ali A.A.
Published: July 2002

It is generally believed that after the emigration of neural crest, the neuroepithelial cells of the neural tube are committed to differentiate only as neurons and supporting cells of the central nervous system. Neural crest cells arise from the dorsal portion of the developing neural tube and contribute to the formation of the peripheral nervous system and a variety of non‐neural structures. In contrast to this view we have recently shown, by focal application of the vital dye Dil in duck embryos, that an additional population of cells emigrates from the neural tube. By using an entirely different technique we confirm and extend these observations in the chick embryo. Replication‐deficient retroviral vector LZ12 containing the gene LacZ was utilized to label the neural tube cells. The viral concentrate was microinjected into the lumen of the rostral hind‐brain neural tube, considerably after the completion of emigration of neural crest cells. The labeled cells were monitored in whole mounts and histological sections. Initially, the labeled cells were restricted to the neuroepithelium of the hindbrain neural tube. Subsequently, they were seen in the neural tube and in the ganglion of the fifth cranial nerve (trigeminal ganglion). Later, they migrated beyond the trigeminal ganglion, i.e., into the mesenchyme of the first pharyngeal arch. Immunostaining with the neural crest cell marker, HNK‐1, indicated that the emigrated neuroepithelial cells were HNK‐1 negative. It is concluded that in the chick embryo some neuroepithelial cells emigrate at the site of attachment of the trigeminal nerve, migrate into the ganglion and then into the mesenchyme of the first arch. This cell population differs antigenically from the neural crest cells.