bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of caffeine on meiotic maturation of porcine oocytes
Authors: Kren Radomir , Ogushi Sugako , Miyano Takashi
Published: May 2004

This study was conducted to evaluate the effect of caffeine on the meiotic maturation of porcine oocytes. Oocyte–cumulus complexes were collected from slaughterhouse-derived ovaries and cultured for 24, 32 or 48 h in medium 199 supplemented with 10% fetal calf serum, 10 μg/ml FSH, 50 μg/ml sodium pyruvate and 50 μg/ml gentamicin in the presence or absence of 2.5 mM caffeine. Caffeine inhibited the meiotic resumption of pig oocytes effectively after 24 h of culture, and 95.5% of oocytes were arrested at the germinal vesicle (GV) stage (control 17.8%, p<0.05). Prolonged culture with caffeine up to 32 h or 48 h, however, resulted in a significant decrease in the inhibitory effect (GV: 13.8% and 8.2%). The number of oocytes at metaphase II after 48 h of culture in the presence of caffeine was significantly lower than that in the control medium (65.3% vs 94.7%, p<0.05). The withdrawal of caffeine after 24 h of culture resulted in the resumption of meiotic maturation, and the oocytes reached metaphase II after 48 h. However, the ability of caffeine-treated oocytes to develop to blastocysts after artificial activation was lower than that of the control (5.5% vs 9.1%, p<0.05). Caffeine treatment significantly increased cAMP levels in the oocytes after 24 h of culture, while both Cdc2 kinase and MAP kinase activation were inhibited in the oocytes. These results suggest that caffeine, similarly to other purine derivatives, prolongs the meiotic arrest of porcine oocytes at the GV stage, perhaps by its action of increasing the cAMP level and by the suppression of Cdc2 kinase and MAP kinase activities in the oocytes.
Analysis of caspase-3, caspase-8 and caspase-9 enzymatic activities in mouse oocytes and zygotes
Authors: Papandile Adrian , Tyas David , O'Malley Donald M. , Warner Carol M.
Published: May 2004

The current consensus in the literature is that ovulated oocytes that are not fertilized die by apoptosis, but the details of the proteins involved in the apoptotic pathways have not been elucidated. In this paper we confirm that caspase-3, the executioner of apoptosis, is expressed in mouse oocytes, and show that two initiators of apoptosis, caspase-8 and caspase-9, are expressed in mouse oocytes. Comparisons were made of caspase-3, -8, and -9 activities in superovulated oocytes that were freshly collected or allowed to age in vivo or in vitro. We found that caspase-3 activity significantly increased in aged oocytes compared with young oocytes (p<0.001), and that both caspase-8 activity and caspase-9 activity decreased in aged oocytes compared with young oocytes (p<0.001 for caspase-8 and p<0.05 for caspase-9 activity). A comparison of superovulated with naturally ovulated oocytes showed the same amount of caspase-8 activity in each, but a significant (p<0.001) decrease in caspase-9 activity in naturally ovulated compared with superovulated oocytes. There was no difference in caspase-3, -8, or -9 activity in oocytes compared with zygotes. Finally, we showed that culture of oocytes in staurosporine increased the activity of caspase-8 and caspase-9. In conclusion, the finding of both caspase-8 and caspase-9 activity in oocytes shows that unfertilized oocytes have the machinery to undergo apoptosis by using either the extrinsic (caspase-8 dependent) or intrinsic (caspase-9 dependent) pathways.
Intrastriatal malonate administration induces convulsive behaviour in rats
Authors: Fleck J. , Ribeiro M. C. P. , Schneider C. M. , Sinhorin V. D. G. , Rubin M. A. , Mello C. F.
Published: May 2004

Summary: Malonic acidaemia is an inborn error of metabolism that accumulates malonate, a competitive succinate dehydrogenase (SDH; EC 1.3.99.1) inhibitor. The present study investigated the behavioural effects of unilateral intrastriatal administration of malonate (0.6, 1.8 or 6 µmol) in adult male Wistar rats (n= 10–13). Low doses of malonate (1.8 µmol) decreased exploratory activity and caused ipsiversive rotational behaviour. High doses of malonate (6 µmol) induced contralateral rotational behaviour and convulsive episodes. Malonate competitively inhibited SDH in mitochondrion‐enriched fractions from striatum (Ki=0.034±0.008 mmol/L). Interestingly, methylmalonate, which is a weaker SDH inhibitor than malonate (Ki=4.22±1.3 mmol/L), induced more convulsions than malonate at equimolar doses and did not cause ipsiversive rotational behaviour. It is suggested that the potency of SDH inhibition in vitro does not correlate positively with the convulsant potential of these inhibitors in vivo.
Carnitine‐acylcarnitine translocase deficiency: Identification of a novel molecular defect in a Bedouin patient
Authors: Galron D. , Birk O. S. , Kazanovitz A. , Moses S. W. , Hershkovitz E.
Published: May 2004

Summary: Carnitine‐acylcarnitine translocase CACT deficiency is a very rare autosomal recessive disease. The neonatal phenotype of CACT deficiency is characterized by hypoketotic hypoglycaemia, hyperammonaemia, cardiomyopathy and skeletal muscle weakness culminating in early death. The disease is caused by mutations in the CACT gene, which encodes a protein transporting long‐chain fatty acid carnitine esters into the mitochondrial matrix. In this report, we describe the first case of CACT deficiency in the Bedouin population in Israel. The patient, the first son of consanguineous parents, was born at term after uneventful delivery. During the second day of life, he developed clinical signs of an acute metabolic crisis with severe hypoglycaemia and hyperammonaemia. Biochemical investigation suggested the diagnosis of CACT deficiency. Genetic molecular analysis confirmed this diagnosis by demonstrating that the affected child was homozygous for a novel missense mutation 793A>G, substituting glutamine by arginine (Q238R) in exon 7 of the CACT gene. Despite medical treatment and adequate nutrition, the patient died at 6 months of age.
The Resource Mothers Study of Maternal Phenylketonuria: Preliminary findings
Authors: Rohr F. , Munier A. , Sullivan D. , Bailey I. , Gennaccaro M. , Levy H. , Brereton H. , Gleason S. , Goss B. , Lesperance E. , Moseley K. , Singh R. , Tonyes L. , Vespa H. , Waisbren S.
Published: May 2004

Summary: Women with phenylketonuria (PKU) must follow a strict low‐phenylalanine diet during pregnancy in order to protect the fetus from the deleterious effects of high maternal blood phenylalanine. The Resource Mothers Study of Maternal PKU was undertaken to determine whether a home visitation programme was effective in helping women with PKU attain blood phenylalanine control earlier during pregnancy. Resource Mothers were trained to provide social support and practical assistance to women with PKU during pregnancy. Eight metabolic clinics in the United States participated in the study. Women with PKU who were planning pregnancy or already pregnant were enrolled in the study and were treated with a low‐phenylalanine diet aimed at controlling blood phenylalanine to 120–360 µmol/L. They were randomly assigned to receive the services of a Resource Mother (RM group) or to a control group. Fifty women were enrolled, and accounted for 44 pregnancies which resulted in 28 live births, and 6 spontaneous abortions. Ten women are currently pregnant and another 6 have not become pregnant. Fifty‐six percent of enrolled women began the diet prior to becoming pregnant. Fifty‐three percent of women in the Resource Mother group were in metabolic control by 10 weeks gestation as compared to 39% in the control group. In addition, women who began diet after pregnancy and had a Resource Mother attained metabolic control earlier (mean gestational age of 22.4 weeks in the RM group vs 29.8 weeks in the control group). There was no difference in birth measurement z‐scores of offspring born to women in the RM group compared to controls. All but 4 women rated themselves as feeling worse about the diet at the end of pregnancy than at the beginning, and few women in either group remained on diet after delivery.
Evidence against clathrate‐derived methane release to Santa Barbara Basin surface waters?
Authors: Cannariato Kevin G. , Stott Lowell D.
Published: May 2004

The Clathrate Gun Hypothesis suggests that methane from the marine sedimentary gas hydrate reservoir was episodically released into the atmosphere where it generated rapid atmospheric warming that drove late Quaternary abrupt millennial‐scale climate change. Brief, large negative δ13C excursions recorded by planktonic (up to −3‰) and benthic (up to −5‰) foraminifera from Santa Barbara Basin sediments have been interpreted as evidence of clathrate‐derived methane release to surface waters during or immediately before marine isotope stage (MIS) 3 interstadials. Molecular biomarkers from the δ13C excursion horizons have been interpreted to support this scenario. However, recent work at modern methane seeps show that fossil specimens can be contaminated with authigenic overgrowths or calcite replacement that may be difficult to detect through microscopy. The possibility that planktonic specimens are contaminated, and thus their δ13C values not a primary signal, warrants further inquiry. We generated a high‐resolution continuous total organic carbon (TOC) δ13C record from fortuitously obtained samples across the younger foraminiferal δ13C excursion during Interstadial 8. The record exhibits variations similar in magnitude and timing to those that occurred in the basin over the last 600 years. Furthermore, previously published TOC δ13C values of discreet samples from this and the three other MIS 3 foraminiferal δ13C excursions are also similar to recent values. Although there are factors that could obscure a surface water methane signal in the TOC δ13C record, these results question the interpretation that methane was released to surface waters. An alternative hypothesis to explain the available data is that the foraminiferal δ13C excursions are an artifact of diagenetic processes at or below the sediment‐water interface. This interpretation may be compatible with the molecular biomarker data. Further work is necessary to differentiate between the two hypotheses.
Correction to “Temporal and Spatial variation of the surface winds in the Gulf of California”
Authors: Marinone S. G. , Parés‐Sierra A. , Castro R. , Mascarenhas A.
Published: May 2004

In the paper “Temporal and Spatial variation of the surface winds in the Gulf of California” by Parés‐Sierra et al. [2003] (Geophys. Res. Lett., 30(6), 1312, doi:10.1029/2004GL016716) it was reported that the monsoon character of the winds over the Gulf of California was not apparent in QuikScat data. Their result was based on the climatological winds derived from an objectively analyzed, gridded, and temporally interpolated data constructed by Tang and Liu [1996] from QuikScat data. A re‐analysis of the original data does show monsoonal winds over the Gulf of California. Therefore, the previous data base is not suited for marginal or local seas.
Locating Science, Locating Salmon: Institutions, Linkages, and Spatial Practices in Early British Columbia Fisheries Science
Authors: Evenden Matthew
Published: May 2004

Fisheries scientists established institutions, engaged metropolitan ideas and local knowledge, and worked out particular spatial practices to produce fisheries science in early-20th-century British Columbia. Problems of distance and the mobility of scientific specimens shaped practices. The difficulties of operating in a peripheral location influenced the institutional development of the field and the emphases of science towards commercially important problems focusing on salmon migration and life history. In this case study I compare and integrate approaches to science and distance from Latour's work and postcolonial historiographies of science in an empirical context.
Deep Roots and Long Shadows: The Cultural Politics of Memory and Longing in Northern New Mexico
Authors: Kosek Jake
Published: May 2004

In this paper I explore the cultural politics of memory and longing in northern New Mexico. The paper begins by examining the ways that, for many Hispanos, land and identity depend on remembered Spanish and Mexican pasts. It continues by showing, through the case of the violent takeover of an old land grant, the political possibilities and contemporary identities that are enabled through the linking of distant past and contemporary land politics. It also demonstrates the ways in which deviating from the past dilutes these same formations and possibilities that accompany these histories—clearly delineated by treaties, deeds, patrimony, etc. The paper then explores—through the contemporary political struggle surrounding the dismembering of a statue erected to commemorate the 400th anniversary of the Spanish arrival in northern New Mexico—the ways in which these very memories also tie Hispanos to alternative violent histories of conquest and colonialism. Ultimately, the paper demonstrates the ways that contemporary land and identity politics in northern New Mexico trap Hispanos between what they need to remember and what others will not let them forget.
Establishment of the introduced kelp Undaria pinnatifida following dieback of the native macroalga Phyllospora comosa in Tasmania, Australia
Authors: Valentine Joseph P. , Johnson Craig R.
Published: May 2004

The Asian kelp Undaria pinnatifida has recently invaded the coastlines of several countries across both hemispheres. Although the occurrence and subsequent spread of the alga has been well documented, the processes underpinning establishment and spread remain poorly understood. Recent work involving canopy manipulations has demonstrated that disturbance to the native algal canopy facilitates establishment of U. pinnatifida sporophytes at high densities, however, the kelp’s response to a natural disruption of the native algal canopy has not been assessed. In summer/autumn 2001, we examined the response of U. pinnatifida to the significant dieback of a common native canopy forming macroalga (Phyllospora comosa) on the east coast of Tasmania. The response of U. pinnatifida and native algae to the dieback was observed during the season for growth of U. pinnatifida sporophytes (spring 2001) and compared with adjacent areas where dieback did not occur. Undaria pinnatifida sporophytes established at high densities (6.75 ± 1.99 stipes m–2) in dieback areas, but remained rare or entirely absent in control areas where the native canopy was intact. The dieback also resulted in bleaching of encrusting algae and increased cover of understorey algae and sediment. The results support the findings of our recent artificial disturbance experiments, confirming the importance of disturbance events for the successful establishment of U. pinnatifida at high densities.
Response of cultured Microcystis aeruginosa from the Swan River, Australia, to elevated salt concentration and consequences for bloom and toxin management in estuaries
Authors: Orr Philip T. , Jones Gary J. , Douglas Grant B.
Published: May 2004

A mixed bloom of Microcystis aeruginosa forma aeruginosa and forma flos-aquae from the Swan River, Western Australia, was confirmed toxic by HPLC analysis. At least four, and possibly 11, microcystins were detected in cell-free extracts. Live bloom material was cultured at salt concentrations up to 21.2 g L–1 (total salts). The cultures were salt tolerant up to 9.8 g L–1. Reduction in the total cell concentration in the first 23 h was only observed in the highest salt treatment and first-order rate constants for cell lysis were higher than the rates for reduction of the intracellular microcystin pool size for that treatment. This suggests preferential lysis of genotypes with lower salinity tolerance and toxigenicity. This increased the toxicity of the mixed bloom population and the apparent microcystin cell quota without any change to the intracellular microcystin pool size. Therefore, the toxicity of bloom material may change through preferential lysis of cells with lower tolerances to changing environmental conditions, including salinity. Managers should be aware that the World Health Organization alert levels of 105 cells mL–1 for human contact exposure to cyanobacteria may not be a suitable prima facie test during these periods.
Fine-scale habitat change in a marine reserve, mapped using radio-acoustically positioned video transects
Authors: Parsons D. M. , Shears N. T. , Babcock R. C. , Haggitt T. R.
Published: May 2004

Large-scale changes in subtidal reef habitats have occurred within the Leigh Marine Reserve (New Zealand) since its establishment in 1976. To determine the extent of habitat change within Goat Island Bay, video transects positioned by a radio acoustic positioning telemetry (RAPT) system were used to map habitats within a Geographic Information System (GIS) framework. This map was compared to a map of the same area constructed 22 years earlier in 1978. Visual categorisation of habitats was consistent with the quantification of habitat-forming species within quadrats, justifying the creation of a map based on visually interpreted video footage. Furthermore, the large-scale changes in habitats were consistent with smaller-scale changes in community structure identified at permanent sites located in the study area. The most obvious changes were the total disappearance of ‘urchin barrens’ across all depths and the recovery of kelp forest in water <8 m, caused by a trophic cascade related to predator recovery. In water > 12 m, the extent of kelp forest and sponge flats was found to decrease by 25 and 33%, respectively, while turfing algal habitat had increased by 50%. This increase in turfing algal habitat had not been previously documented due to the spatial scale of traditional sampling methods.
Effect of sperm concentration, medium osmolality and oocyte storage on artificial fertilisation success in a myobatrachid frog (Limnodynastes tasmaniensis)
Authors: Edwards D. L. , Mahony M. J. , Clulow J.
Published: May 2004

The present study optimised artificial fertilisation and oocyte storage conditions in Limnodynastes tasmaniensis (Myobatrachidae). Data on general reproductive biology, the effect of sperm motility and concentration, medium osmolality and oocyte storage on artificial fertilisation success are presented. Egg number was most strongly correlated with bodyweight (r = 0.819). Sperm yield was correlated with testes weight (r = 0.827), which was strongly correlated with snout–vent length (r = 0.772). Optimal artificial fertilisation occurred in 0–7 mOsm kg–1 amphibian Ringer, similar to ranid, bufonid and hylid species. High fertilisation rates were achieved using spermatozoa with little forwards progressive motility at comparatively low concentrations (3 × 104 sperm cells mL–1) and with no relationship between percentage sperm motility and fertilisation success (correlation of fertilisation rate with sperm motility after activation: r = –0.145). Oocytes stored in 5 mOsm kg–1 solutions showed no significant decline in fertilisability after 2 h, showing that swelling of the jelly surrounding the eggs does not prevent sperm from fusing with the oocyte in this species. Fertilisability of oocytes was extended to > 4 h in medium to high osmolality solutions (124–271 mOsm kg–1). These data allow for the future use of L. tasmaniensis in developing assisted reproductive technology protocols for foam-nesting myobatrachid species, many of which are now threatened with extinction in the wild.
Effect of delayed breeding on the reproductive performance of female mice
Authors: Tarín J. J. , Gómez-Piquer V. , Rausell F. , Hermenegildo C. , Cano A.
Published: May 2004

The aim of the present study was to determine, in the mouse, whether maintaining females as virgins until an advanced reproductive age was associated with decreased reproductive performance and reproductive lifespan compared with females of the same age that were first mated with males at an earlier reproductive age. Randomly selected virgin hybrid (C57BL/6JIco female × CBA/JIco male) female mice were housed individually with a randomly selected 12- to 14-week-old hybrid male either at the age of 28 weeks (normal breeding group; n = 20) or 51 weeks (delayed breeding group; n = 23) for the rest of their reproductive life. Females were checked once daily to determine the day of parturition and to record the litter size and gender of pups at birth for each consecutive litter. At weaning, offspring were weighed and killed. Delayed breeding was associated with smaller litter sizes, both at birth and at weaning, a higher bodyweight of pups at weaning, a higher percentage of litters with at least one newborn pup cannibalised, earlier cessation of female reproductive life and a higher mortality rate of dams during the breeding period. These results show that delayed breeding in the mouse is associated with decreased reproductive performance and a shorter reproductive lifespan compared with females bred at an earlier reproductive age.
3D structure of human FK506-binding protein 52: Implications for the assembly of the glucocorticoid receptor/Hsp90/immunophilin heterocomplex
Authors: Wu Beili , Li Pengyun , Liu Yiwei , Lou Zhiyong , Ding Yi , Shu Cuiling , Ye Sheng , Bartlam Mark , Shen Beifen , Rao Zihe
Published: May 2004

FK506-binding protein 52 (FKBP52), which binds FK506 and possesses peptidylprolyl isomerase activity, is an important immunophilin involved in the heterocomplex of steroid receptors with heat-shock protein 90. Here we report the crystal structures of two overlapped fragments [N(1–260) and C(145–459)] of FKBP52 and the complex with a C-terminal pentapeptide from heat-shock protein 90. Based on the structures of these two overlapped fragments, the complete putative structure of FKBP52 can be defined. The structure of FKBP52 is composed of two consecutive FKBP domains, a tetratricopeptide repeat domain and a short helical domain beyond the final tetratricopeptide repeat motif. Key structural differences between FKBP52 and FKBP51, including the relative orientations of the four domains and some important residue substitutions, could account for the differential functions of FKBPs.
The distribution of fitness effects caused by single-nucleotide substitutions in an RNA virus
Authors: Sanjuán Rafael , Moya Andrés , Elena Santiago F.
Published: May 2004

Little is known about the mutational fitness effects associated with single-nucleotide substitutions on RNA viral genomes. Here, we used site-directed mutagenesis to create 91 single mutant clones of vesicular stomatitis virus derived from a common ancestral cDNA and performed competition experiments to measure the relative fitness of each mutant. The distribution of nonlethal deleterious effects was highly skewed and had a long, flat tail. As expected, fitness effects depended on whether mutations were chosen at random or reproduced previously described ones. The effect of random deleterious mutations was well described by a log-normal distribution, with -19% reduction of average fitness; the effects distribution of preobserved deleterious mutations was better explained by a β model. The fit of both models was improved when combined with a uniform distribution. Up to 40% of random mutations were lethal. The proportion of beneficial mutations was unexpectedly high. Beneficial effects followed a γ distribution, with expected fitness increases of 1% for random mutations and 5% for preobserved mutations.
Nitrous oxide (N
2
O) requires the
N
-methyl-
d
-aspartate receptor for its action in
Caenorhabditis elegans
Authors: Nagele P. , Metz L. B. , Crowder C. M.
Published: May 2004

Nitrous oxide (N
2
O, also known as laughing gas) and volatile anesthetics (VAs), the original and still most widely used general anesthetics, produce anesthesia by ill-defined mechanisms. Electrophysiological experiments in vertebrate neurons have suggested that N
2
O and VAs may act by distinct mechanisms; N
2
O antagonizes the
N
-methyl-
d
-aspartate (NMDA) subtype of glutamate receptors, whereas VAs alter the function of a variety of other synaptic proteins. However, no genetic or pharmacological experiments have demonstrated that any of these
in vitro
actions are responsible for the behavioral effects of either class of anesthetics. By using genetic tools in
Caenorhabditis elegans
, we tested whether the action of N
2
O requires the NMDA receptor
in vivo
and whether its mechanism is shared by VAs. Distinct from the action of VAs, N
2
O produced behavioral defects highly specific and characteristic of that produced by loss-of-function mutations in both NMDA and non-NMDA glutamate receptors. A null mutant of
nmr-1
, which encodes a
C. elegans
NMDA receptor, was completely resistant to the behavioral effects of N
2
O, whereas a non-NMDA receptor-null mutant was normally sensitive. The N
2
O-resistant
nmr-1
(null) mutant was not resistant to VAs. Likewise, VA-resistant mutants had wild-type sensitivity to N
2
O. Thus, the behavioral effects of N
2
O require the NMDA receptor NMR-1, consistent with the hypothesis formed from vertebrate electrophysiological data that a major target of N
2
O is the NMDA receptor.
MesA, a Novel Fungal Protein Required for the Stabilization of Polarity Axes inAspergillus nidulans
Authors: Pearson Claire L. , Xu Kaimei , Sharpless Kathryn E. , Harris Steven D.
Published: May 2004

The Aspergillus nidulans proteome possesses a single formin, SepA, which is required for actin ring formation at septation sites and also plays a role in polarized morphogenesis. Previous observations imply that complex regulatory mechanisms control the function of SepA and ensure its correct localization within hyphal tip cells. To characterize these mechanisms, we undertook a screen for mutations that enhance sepA defects. Of the mutants recovered, mesA1 causes the most dramatic defect in polarity establishment when SepA function is compromised. In a wild-type background, mesA1 mutants undergo aberrant hyphal morphogenesis, whereas septum formation remains unaffected. Molecular characterization revealed that MesA is a novel fungal protein that contains predicted transmembrane domains and localizes to hyphal tips. We show that MesA promotes the localized assembly of actin cables at polarization sites by facilitating the stable recruitment of SepA. We also provide evidence that MesA may regulate the formation or distribution of sterol-rich membrane domains. Our results suggest that these domains may be part of novel mechanism that directs SepA to hyphal tips.
Atg21 Is a Phosphoinositide Binding Protein Required for Efficient Lipidation and Localization of Atg8 during Uptake of Aminopeptidase I by Selective Autophagy
Authors: Strømhaug Per E. , Reggiori Fulvio , Guan Ju , Wang Chao-Wen , Klionsky Daniel J.
Published: May 2004

Delivery of proteins and organelles to the vacuole by autophagy and the cytoplasm to vacuole targeting (Cvt) pathway involves novel rearrangements of membrane resulting in the formation of vesicles that fuse with the vacuole. The mechanism of vesicle formation and the origin of the membrane are complex issues still to be resolved. Atg18 and Atg21 are proteins essential to vesicle formation and together with Ygr223c form a novel family of phosphoinositide binding proteins that are associated with the vacuole and perivacuolar structures. Their localization requires the activity of Vps34, suggesting that phosphatidylinositol(3)phosphate may be essential for their function. The activity of Atg18 is vital for all forms of autophagy, whereas Atg21 is required for the Cvt pathway but not for nitrogen starvation-induced autophagy. The loss of Atg21 results in the absence of Atg8 from the pre-autophagosomal structure (PAS), which may be ascribed to a reduced rate of conjugation of Atg8 to phosphatidylethanolamine. A similar defect in localization of a second ubiquitin-like conjugate, Atg12-Atg5, suggests that Atg21 may be involved in the recruitment of membrane to the PAS.
Diagnosis and Pathology of Unilateral Maxillary Sinus Opacification with or without Evidence of Contralateral Disease
Authors: Kaplan Brian A. , Kountakis Stilianos E.
Published: May 2004

Objective: Determine the diagnostic criteria and etiology of complete unilateral maxillary sinus opacification.

Methods: A prospective analysis was performed on patients presenting to a tertiary care rhinology practice with complaints of chronic rhinosinusitis or acute exacerbation. Sixty‐four consecutive patients were identified with unilateral maxillary sinus opacification on computed tomography (CT) scan after at least a 3‐week medical therapy for rhinosinusitis. The study population comprised 30 men and 34 women with a mean age of 47.0 years. All patients completed a symptom score questionnaire, received nasal endoscopy, and CT imaging. Patient symptoms and endoscopic and radiographic findings were analyzed to determine patterns related to final diagnosis.

Results: All 64 patients underwent functional endoscopic sinus surgery. Each surgical specimen was sent for pathologic confirmation of the diagnosis. Sixteen mucoceles, 12 cases of nasal polyposis, 27 cases of acute or chronic sinusitis, 7 cases of inverting papilloma, and 2 cases of mycetoma were identified. Endoscopic and radiographic appearances were correlated with each disease process.

Conclusion: Unilateral maxillary sinus opacification is a relatively common finding. Early identification of inverting papillomas and mucoceles may avoid delay in surgical intervention, whereas acute/chronic rhinosinusitis and nasal polyposis can initially be managed medically. Careful history, endoscopic examination, and radiographic studies can often determine the responsible disease process.
Intraepithelial Nerve Fibers Project Into the Lumen of the Larynx
Authors: Lima‐Rodrigues Manuel , Nunes Rui , Almeida Armando
Published: May 2004

Objectives/Hypothesis: Studies on the morphology and location of the sensory receptors in the laryngeal mucosa have resulted in insufficient and sometimes conflicting data. In the present study the authors analyzed the distribution and morphology of sensory nerve plexuses and terminal fibers in the laryngeal mucosa of the rat.

Study Design: Two groups of Male Wistar rats were used in this laboratory study; the larynx of the first group were used to analyse the sensitive innervation of its epithelium, whereas the larynx of the second group (controls) were tested for the specificity of the antibodies used.

Methods: The larynges of the animals were entirely removed after perfusion, and coronal or horizontal sections were immunoprocessed for further randomized analysis of the mucosa. Primary afferents were detected by immunoreaction to two widely recognized markers of sensory nerves, calcitonin gene‐related peptide and substance P, and visualized using diaminobenzidine as a chromogen.

Results: The nerve plexuses were more densely distributed in the dorsal half of the vocal folds and in the laryngeal aspect of the epiglottis. Dense networks of fine fibers with many varicosities en passant, immunoreactive for both calcitonin gene‐related peptide and substance P, occurred in the lamina propria and along the epithelial thickness. Calcitonin gene‐related peptide–immunoreactive and substance P–immunoreactive fibers extended across the epithelium and projected to the laryngeal lumen itself, reaching the space between the cilia.

Conclusion: The projection of intraepithelial nerve fibers into the lumen of the larynx indicates that in the absence of mucus, nerve endings may be exposed and thus receive direct stimulation from airborne substances. Furthermore, it suggests that the laryngeal mucosa of the rat may constitute an experimental model for studying the direct activation or manipulation of primary afferents at the periphery and neurogenic inflammation.
Medialization Laryngoplasty With Strap Muscle Transposition for Vocal Fold Atrophy with or without Sulcus Vocalis
Authors: Su Chih‐Ying , Tsai Shang‐Shyue , Chiu Jeng‐Fen , Cheng Chu‐An
Published: May 2004

Objective: Vocal fold atrophy with or without sulcus vocalis may result in a spindle‐shaped glottal incompetence (SGI). Because of varying drawbacks with all existing materials (e.g., Silastic block, Teflon, fat, etc.) used for medialization or augmentation of the atrophic vocal folds, there is a need to supplant these materials with a more stable, autologous tissue to correct the SGI.

Study Design: Thirty‐two patients with vocal fold atrophy underwent medialization laryngoplasty with strap muscle transposition.

Methods: Under local or general anesthesia, the thyroid lamina on the more affected side was vertically incised 5 mm off the midline. The inner perichondrium was carefully elevated from the overlying thyroid ala. Care was taken not to enter the laryngeal lumen. After dividing the thyrohyoid and cricothyroid membranes, the lamina was retracted laterally. To accommodate the muscle flap more easily, the caudal edge of the lamina was trimmed using a small burr. A bipedicled strap muscle flap was then transposed into the space between the lamina and the paraglottic soft tissue. The thyroid cartilages were carefully sutured back in place. All patients underwent pre‐ and postoperative voice evaluations including laryngostroboscopy, perceptual assessment, and acoustic and aerodynamic analyses. Patients who had been followed up for more than 3 months were enrolled in this study.

Results: A total of 27 of the 32 patients with complete pre‐ and postoperative voice function measurements were included in the analysis. Vocal improvement was demonstrated in 26 of these 27 (96%) patients. No dyspnea or other major complications were noted in any patients.

Conclusion: The results indicate that medialization laryngoplasty with strap muscle transposition is a prosthesis‐free, safe, and effective technique for correcting SGI caused by vocal fold atrophy.
Science from India
Authors: Cook A.
Published: May 2004

Introduction to the January 1998 issue of
Notes and Records
.
Hooke's cubico–parabolical conoid
Authors: Heyman J.
Published: May 2004

In 1675 Robert Hooke published, as one of his ‘Inventions’, a Latin anagram concerning the ‘true...form of all manner of arches for building’. His discovery was that the shape of a light flexible cord subjected to specified loads would, when inverted, give the required shape of the perfect (masonry) arch to carry those same loads. Hooke knew that the catenary curve was not given by the parabola
y
=
ax
2
, but he was unable to solve the problem mathematically, and the decipherment of the anagram was not published until after his death. Four years earlier Hooke had stated to the Royal Society that the solution to the corresponding three–dimensional problem, that of the shape of the perfect dome, was the cubico–parabolical conoid; that is, the dome was formed by rotating the cubic parabola
y
=
ax
3
about the
y
–axis. It is shown that the correct form of dome may be evaluated in terms of the integrals erf(
t
) and erg(
t
). Moreover, an alternative solution as a power series is rapidly convergent, and has a leading term in
x
3
followed by a much smaller term in
x
7
. Wren's design for the dome of St Paul's Cathedral made use of the idea of Hooke's ‘hanging chain’.
George Smith: publisher
Authors: Glasgow Eric
Published: May 2004

This is a brief study of the character, and the professional career, of one of the most spectacular and prolific of all the huge medley of book‐publishers in Victorian London. George Smith is perhaps today somewhat overshadowed by other famous names. Nevertheless, in 1944, the Cambridge historian, G.M. Trevelyan, singled him from the rest: as the publisher of the monumental Dictionary of National Biography. As the nineteenth century’s cult of printed books inevitably now recedes in favour of information technology, perhaps the time is ripe for this succinct evaluation of an extraordinary publisher from Victorian times who promoted not only works by Leslie Stephen, Thackeray, and many other literary men but particularly works by women‐novelists, such as Charlotte Bronte and Elizabeth Gaskell, despite the fact that he was far from being a “feminist”, in our own contemporary sense.
Flexible jobs: changing patterns in information and library work
Authors: Hannabuss Stuart
Published: May 2004

The article describes the various forms in which flexible jobs appear in the information and library field, and discusses the implications for the stakeholders ‐ employees, employers, and users. It is suggested that flexibility is here to stay in a world of turbulent change but presents a number of important challenges for effective service delivery now and in the near future.
Buy Brown’s book!
Authors: Thompson Craig J.
Published: May 2004

Provides a fully impartial commentary on Stephen Brown’s Postmodern Marketing. Implores readers to ignore all rumours to the contrary. Notes that it is very difficult to summarize this commentary in 100 words or less and refuses to even try. Nonetheless, the author says he worked quite hard on this paper and that you really must read it, lest you will be overwhelmed with guilt and subject to a dreadful curse. Also pledges to get even with the author’s anonymous reviewers. Finally, reports that the author has been under a great deal of stress lately but that his therapy has been going well.
Second order cybernetics ‐ implications in real life
Authors: Ghosal A.
Published: May 2004

The second order cybernetics rests on the promise that the system definition includes the observer/researcher as a key element. While the first order cybernetics is mainly directed towards problems of control and homeostasis relating to physical and engineering systems, the second order cybernetics (SOC) also considers problems of growth and morphogenesis in biological, economic and social systems. This paper gives an exposition of SOC and its applications.
Using Pooled Exposure Assessment to Improve Efficiency in Case‐Control Studies
Authors: Weinberg Clarice R. , Umbach David M.
Published: May 2004

Summary. Assays can be so expensive that interesting hypotheses become impractical to study epidemiologically. One need not, however, perform an assay for everyone providing a biological specimen. We propose pooling equal‐volume aliquots from randomly grouped sets of cases and randomly grouped sets of controls, and then assaying the smaller number of pooled samples. If an effect modifier is of concern, the pooling can be done within strata defined by that variable. For covariates assessed on individuals (e.g., questionnaire data), set‐based counterparts are calculated by adding the values for the individuals in each set. The pooling set then becomes the unit of statistical analysis. We show that, with appropriate specification of a set‐based logistic model, standard software yields a valid estimated exposure odds ratio, provided the multiplicative formulation is correct. Pooling minimizes the depletion of irreplaceable biological specimens and can enable additional exposures to be studied economically. Statistical power suffers very little compared with the usual, individual‐based analysis. In settings where high assay costs constrain the number of people an investigator can afford to study, specimen pooling can make it possible to study more people and hence improve the study's statistical power with no increase in cost.
Estimation in Independent Observer Line Transect Surveys for Clustered Populations
Authors: Chen Song Xi
Published: May 2004

Summary. This paper introduces a framework for animal abundance estimation in independent observer line transect surveys of clustered populations. The framework generalizes an approach given in Chen (1999, Environmental and Ecological Statistics6, in press) to accommodate heterogeneity in detection caused by cluster size and other covariates. Both parametric and nonparametric estimators for the local effective search widths, given the covariates, can be derived from the framework. A nonparametric estimator based on conditional kernel density estimation is proposed and studied owing to its flexibility in modeling the detection functions. A real data set on harbor porpoise in the North Sea is analyzed.
Likelihood Models for Clustered Binary and Continuous Out comes: Application to Developmental Toxicology
Authors: Regan Meredith M. , Catalano Paul J.
Published: May 2004

Summary. In developmental toxicology, methods based on dose‐response modeling and quantitative risk assessment are being actively pursued. Among live fetuses, the presence of malformations and reduction in fetal weight are of primary interest, but ordinarily, the dose‐response relationships are characterized in each of the outcomes separately while appropriately accounting for clustering within litters. Jointly modeling the outcomes, allowing different relationships with dose while incorporating the correlation between the fetuses and the outcomes, may be more appropriate. We propose a likelihood‐based model that is an extension of a correlated probit model to incorporate continuous outcomes. Our model maintains a marginal dose–response interpretation for the individual outcomes while taking into account both the correlations between outcomes on an individual fetus and those due to clustering. The joint risk of malformation and low birth weight can then be estimated directly. This approach is particularly well suited to estimating safe dose levels as part of quantitative risk assessment.
Local Bandwidth Selection for Kernel Estimation of Population Densities with Line Transect Sampling
Authors: Gerard Patrick D. , Schucany William R.
Published: May 2004

Summary. Seber (1986, Biometrics42, 267–292) suggested an approach to biological population density estimation using kernel estimates of the probability density of detection distances in line transect sampling. Chen (1996a, Applied Statistics45, 135–150) and others have employed cross validation to choose a global bandwidth for the kernel estimator or have suggested adaptive kernel estimation (Chen, 1996b, Biometrics52, 1283–1294). Because estimation of the density is required at only a single point, we investigate a local bandwidth selection procedure that is a modification of the method of Schucany (1995, Journal of the American Statistical Association90, 535–540) for nonparametric regression. We report on simulation results comparing the proposed method and a local normal scale rule with cross validation and adaptive estimation. The local bandwidths and normal scale rule produce estimates with mean squares that are half the size of the others in most cases. Consistency results are also provided.
A Condition for Designing Bus‐Route Type Access Site Surveys to Estimate Recreational Fishing Effort
Authors: Chen Song Xi , Woolcock Jodie L.
Published: May 2004

Summary. A theoretical framework for using bus‐route surveys to estimate recreational fishing effort has been established by taking into account the arrival and departure distributions of the fishing parties. Properties of a fishing effort estimator proposed by Robson and Jones (1989) are investigated. It is found that the estimator is not automatically unbiased; rather, a condition on the survey design has to be satisfied in order to be unbiased. The condition is simple and can be easily implemented.
Selection Models and Pattern‐Mixture Models for Incomplete Data with Covariates
Authors: Michiels Bart , Molenberghs Geert , Lipsitz Stuart R.
Published: May 2004

Summary. Most models for incomplete data are formulated within the selection model framework. This paper studies similarities and differences of modeling incomplete data within both selection and pattern‐mixture settings. The focus is on missing at random mechanisms and on categorical data. Point and interval estimation is discussed. A comparison of both approaches is done on side effects in a psychiatric study.
Estimating Equations with Nonignorably Missing Response Data
Authors: Wang You‐Gan
Published: May 2004

Summary. Troxel, Lipsitz, and Brennan (1997, Biometrics53, 857–869) considered parameter estimation from survey data with nonignorable nonresponse and proposed weighted estimating equations to remove the biases in the complete‐case analysis that ignores missing observations. This paper suggests two alternative modifications for unbiased estimation of regression parameters when a binary outcome is potentially observed at successive time points. The weighting approach of Robins, Rotnitzky, and Zhao (1995, Journal of the American Statistical Association90, 106–121) is also modified to obtain unbiased estimating functions. The suggested estimating functions are unbiased only when the missingness probability is correctly specified, and misspecification of the missingness model will result in biases in the estimates. Simulation studies are carried out to assess the performance of different methods when the covariate is binary or normal. For the simulation models used, the relative efficiency of the two new methods to the weighting methods is about 3.0 for the slope parameter and about 2.0 for the intercept parameter when the covariate is continuous and the missingness probability is correctly specified. All methods produce substantial biases in the estimates when the missingness model is misspecified or underspecified. Analysis of data from a medical survey illustrates the use and possible differences of these estimating functions.
A New Approach to Modeling Daily Probabilities of Conception
Authors: Royston Patrick , Ferreira Alberto
Published: May 2004

Summary. Standard conception probabilities models assume that different acts of intercourse make independent contributions to the probability of conception in viable cycles. We propose an alternative, approximate model based on the assumption that the act of intercourse closest to the time of maximum fertility is the one most likely to have caused conception. We describe an adaptive algorithm [the most fertile intercourse day (MFID) algorithm] that estimates the most fertile intercourse day in each cycle. The approach is easily extended to include covariates and random between‐couple differences in fecundability that affect the probability of conception in a given cycle. Reanalyses of two data sets reported in the literature are presented. Estimates of the probability of conception during the most fertile period of the cycle and of the effects of covariates are similar to estimates found using standard models.
Properties of A Nonparametric Test for Early Comparison of Treatments in Clinical Trials in the Presence of Surrogate Endpoints
Authors: Venkatraman E. S. , Begg Colin B.
Published: May 2004

Summary. A nonparametric test is derived for comparing treatments with respect to the final endpoint in clinical trials in which the final endpoint has been observed for a random subset of patients, but results are available for a surrogate endpoint for a larger sample of patients. The test is an adaptation of the Wilcoxon–Mann–Whitney two‐sample test, with an adjustment that involves a comparison of the ranks of the surrogate endpoints between patients with and without final endpoints. The validity of the test depends on the assumption that the patients with final endpoints represent a random sample of the patients registered in the study. This assumption is viable in trials in which the final endpoint is evaluated at a “landmark” timepoint in the patients' natural history. A small sample simulation study demonstrates that the test has a size that is close to the nominal value for all configurations evaluated. When compared with the conventional test based only on the final endpoints, the new test delivers substantial increases in power only when the surrogate endpoint is highly correlated with the true endpoint. Our research indicates that, in the absence of modeling assumptions, auxiliary information derived from surrogate endpoints can provide significant additional information only under special circumstances.