A computational study of functional endoscopic sinus surgery and maxillary sinus drug delivery.

BACKGROUND: Topical medication is increasingly used following functional endoscopic sinus surgery (FESS). Information on particle sizes that maximise maxillary sinus (MS) delivery is conflicting, and the effect of antrostomy size on delivery is unclear. The purpose of this study was to estimate antrostomy and particle size effects on topical MS drug delivery. METHODOLOGY: Sinonasal reconstructions were created from a pre- and a post-FESS CT scan in each of four chronic rhinosinusitis patients. Additional models were created from each post-FESS reconstruction representing four alternative antrostomy sizes. Airflow and particle deposition were simulated in each reconstruction using computational fluid dynamics for nebulised and sprayed delivery. RESULTS: MS ventilation and drug delivery increased following FESS, the largest virtual antrostomy led to greatest delivery, and MS delivery was sensitive to particle size. Particles within a 5-18 µm and 5-20 µm size range led to peak MS deposition for nebulised and sprayed particles, respectively. Post-FESS increases in drug delivery varied across individuals and within individuals by the type of antrostomy created. CONCLUSION: Our findings suggest that FESS, particularly with larger antrostomies, improves topical drug delivery, and that certain particle sizes improve this delivery. Further research is needed to contextualise these findings with other post-surgical effects.

The detection of large HNO3-containing particles in the winter Arctic stratosphere.

Large particles containing nitric acid (HNO3) were observed in the 1999/2000 Arctic winter stratosphere. These in situ observations were made over a large altitude range (16 to 21 kilometers) and horizontal extent (1800 kilometers) on several airborne sampling flights during a period of several weeks. With diameters of 10 to 20 micrometers, these sedimenting particles have significant potential to denitrify the lower stratosphere. A microphysical model of nitric acid trihydrate particles is able to simulate the growth and sedimentation of these large sizes in the lower stratosphere, but the nucleation process is not yet known. Accurate modeling of the formation of these large particles is essential for understanding Arctic denitrification and predicting future Arctic ozone abundances.

Energy-dependent nucleolar localization of p53 in vitro requires two discrete regions within the p53 carboxyl terminus.

The p53 tumor suppressor is a nucleocytoplasmic shuttling protein that is found predominantly in the nucleus of cells. In addition to mutation, abnormal p53 cellular localization is one of the mechanisms that inactivate p53 function. To further understand features of p53 that contribute to the regulation of its trafficking within the cell, we analysed the subnuclear localization of wild-type and mutant p53 in human cells that were either permeabilized with detergent or treated with the proteasome inhibitor MG132. We, here, show that either endogenously expressed or exogenously added p53 protein localizes to the nucleolus in detergent-permeabilized cells in a concentration- and ATP hydrolysis-dependent manner. Two discrete regions within the carboxyl terminus of p53 are essential for nucleolar localization in permeabilized cells. Similarly, localization of p53 to the nucleolus after proteasome inhibition in unpermeabilized cells requires sequences within the carboxyl terminus of p53. Interestingly, genotoxic stress markedly decreases the association of p53 with the nucleolus, and phosphorylation of p53 at S392, a site that is modified by such stress, partially impairs its nucleolar localization. The possible significance of these findings is discussed.

Clinical Validation of a Predictive Model for the Presence of Cervical Lymph Node Metastasis in Papillary Thyroid Cancer.

BACKGROUND AND PURPOSE: Ultrasound is a standard technique to detect lymph node metastasis in papillary thyroid cancer. Cystic changes and microcalcifications are the most specific features of metastasis, but with low sensitivity. This prospective study compared the diagnostic accuracy of a predictive model for sonographic evaluation of lymph nodes relative to the radiologist's standard assessment in detecting papillary thyroid cancer metastasis in patients after thyroidectomy. MATERIALS AND METHODS: Cervical lymph node sonographic images were reported by a radiologist (R method) per standard practice. The same images were independently evaluated by another radiologist using a sonographic predictive model (M method). A test was considered positive for metastasis if the R or M method suggested lymph node biopsy. The result of lymph node biopsy or surgical pathology was used as the reference standard. We estimated relative true-positive fraction and relative false-positive fraction using log-linear models for correlated binary data for the M method compared with the R method. RESULTS: A total of 237 lymph nodes in 103 patients were evaluated. Our analysis of relative true-positive fraction and relative false-positive fraction included 54 nodes with pathologic results in which at least 1 method (R or M) was positive. The M method had a higher relative true-positive fraction of 1.46 (95% CI, 1.12-1.91; P = .006) and a lower relative false-positive fraction of 0.58 (95% CI, 0.36-0.92; P = .02) compared with the R method. CONCLUSIONS: The sonographic predictive model outperformed the standard assessment to detect lymph node metastasis in patients with papillary thyroid cancer and may reduce unnecessary biopsies.

Correction: Energy-dependent nucleolar localization of p53 in vitro requires two discrete regions within the p53 carboxyl terminus.

Following the publication of this article the authors noted that two images were duplicated in Figure 2B. The corrected figure 2B is below. The authors wish to apologize for any inconvenience caused.

HRT: have we changed?

BACKGROUND: In recent years, medical controversy, has surrounded the prescribing of hormone replacement therapy (HRT). AIM: This study aimed to establish whether prescribing of HRT in Northern Ireland has changed and what the current prescribing patterns are. METHOD: A structured questionnaire was sent by post to all medical staff in Obstetrics and Gynaecology in Northern Ireland. A stamped addressed envelope was included. RESULTS: Overall 54% of respondents indicated that they had changed their prescribing practice on HRT in the past year. The primary indication for prescribing HRT was vasomotor symptoms (93%). Fifty-six per cent of doctors recommended 1-5 years as duration of use. Oral preparations were those most commonly prescribed (57%). The dose and type chosen were the same whether prescribing had changed or not. CONCLUSIONS: More than half of all doctors who responded had changed their prescribing practices on HRT, yet some respondents still preferred more traditional prescribing.

An ecosystem-scale perspective of the net land methanol flux: synthesis of micrometeorological flux measurements.

Methanol is the second most abundant volatile organic compound in the troposphere and plays a significant role in atmospheric chemistry. While there is consensus about the dominant role of living plants as the major source and the reaction with OH as the major sink of methanol, global methanol budgets diverge considerably in terms of source/sink estimates reflecting uncertainties in the approaches used to model, and the empirical data used to separately constrain these terms. Here we compiled micrometeorological methanol flux data from eight different study sites and reviewed the corresponding literature in order to provide a first cross-site synthesis of the terrestrial ecosystem-scale methanol exchange and present an independent data-driven view of the land-atmosphere methanol exchange. Our study shows that the controls of plant growth on the production, and thus the methanol emission magnitude, and stomatal conductance on the hourly methanol emission variability, established at the leaf level, hold across sites at the ecosystem-level. Unequivocal evidence for bi-directional methanol exchange at the ecosystem scale is presented. Deposition, which at some sites even exceeds methanol emissions, represents an emerging feature of ecosystem-scale measurements and is likely related to environmental factors favouring the formation of surface wetness. Methanol may adsorb to or dissolve in this surface water and eventually be chemically or biologically removed from it. Management activities in agriculture and forestry are shown to increase local methanol emission by orders of magnitude; they are however neglected at present in global budgets. While contemporary net land methanol budgets are overall consistent with the grand mean of the micrometeorological methanol flux measurements, we caution that the present approach of simulating methanol emission and deposition separately is prone to opposing systematic errors and does not allow taking full advantage of the rich information content of micrometeorological flux measurements.

Isolation and characterization of the naphthocyclinone gene cluster from Streptomyces arenae DSM 40737 and heterologous expression of the polyketide synthase genes.

Streptomyces arenae produces the aromatic polyketide naphthocyclinone, which exhibits activity against Gram-positive bacteria. A cosmid clone containing the putative naphthocyclinone gene cluster was isolated from a genomic library of S. arenae by hybridization with a conserved region from the actinorhodin PKS of S. coelicolor. Sequence analysis of a 5.5-kb DNA fragment, which hybridizes with the actI probe, revealed three open reading frames coding for the minimal polyketide synthase. A strong sequence similarity was found to several previously described ketosynthases, chain length factors and acyl carrier proteins from other polyketide gene clusters. An additional open reading frame downstream of the PKS genes of S. arenae showed 53% identity to act VII probably encoding an aromatase. Another open reading frame was identified in a region of 1.436 bp upstream of the PKS genes, which, however, had no similarity to known genes in the database. Approximately 8 kb upstream of the PKS genes, a DNA fragment was identified that hybridizes to an actVII--actIV specific probe coding for a cyclase and a putative regulatory protein, respectively. Disruption of the proposed naphthocyclinone gene cluster by insertion of a thiostrepton resistance gene completely abolished production of naphthocyclinones in the mutant strain, showing that indeed the naphthocyclinone gene cluster had been isolated. Heterologous expression of the minimal PKS genes in S. coelicolor CH999 in the presence of the act ketoreductase led to the production of mutactin and dehydromutactin, indicating that the S. arenae polyketide synthase forms a C-16 backbone that is subsequently dimerized to build naphthocyclinone. The functions of the proposed cyclase and aromatase were examined by coexpression with genes from different polyketide core producers.

Immunoelectrophoresis employing avian antisera for the detection and quantitation of Pasteurella multocida antigens.

Immunoelectrophoresis with various buffer systems at high and low pH was examined for suitability to detect and quantitate Pasteurella multocida antigens with turkey or chicken anti-P. multocida sera. Counterimmunoelectrophoresis was used to develop a buffer system for one-dimensional, two-dimensional, and rocket immunoelectrophoresis. The effects of pH, buffer, and molarity on resolution of immunoprecipitates were determined; 0.05 M sodium acetate-acetic acid buffer at pH 5.6 was the most suitable buffer. This buffer could be used in counterimmunoelectrophoresis with turkey or chicken sera to detect minute amounts of P. multocida protein antigens (4.3 ng/test) or lipopolysaccharide (3.12 micrograms/test). One-dimensional immunoelectrophoresis with the acetate buffer system required treatment of the gels with a 17% NaCl solution to induce immunoprecipitation of P. multocida lipopolysaccharide. Other techniques using the acetate buffer system did not require the high salt treatment. In two-dimensional immunoelectrophoresis, antisera migrated in the second dimension at pH 8.6, but did not migrate at pH 5.6. Rocket immunoelectrophoresis with the acetate buffer system was effective for quantitating P. multocida antigens.

A practical guide to prescribing hormone replacement therapy.

Over the past 20 years there has been increasing interest in the menopause and hormone replacement therapy (HRT). More recently, postmenopausal HRT has been seen as a specific treatment for symptoms in the short term and preventative therapy in the long term. Women must be counselled regarding the risks and benefits of HRT according to the best available evidence. The patient should also be actively involved in the decision regarding HRT therapy, which should then improve patient compliance. Generally, an appropriate regimen of HRT can be formulated for the majority of patients. Progestogen should be added to therapy in women with an intact uterus in a cyclical or continuous regimen. The management of common estrogenic and progestogenic adverse effects is important in improving compliance. At present, new drugs are being developed for the management of the menopause (selective estrogen receptor modulators and phytoestrogens). Obviously, further research will be necessary to determine whether these drugs have advantages over regular HRT. By offering postmenopausal women HRT an attempt is made to optimise their physical and psychological well-being. However, HRT is not without adverse effects, the most worrying of which is the possible increase in breast cancer risk with long term use. However, with patient education efforts, treatment regimens acceptable to both patient and practitioner can be initiated; in this regard, the aim of the practitioner should be to help the menopausal woman make the decision which is the most appropriate for her.

Novel and recurrent mutations in lamin A/C in patients with Emery-Dreifuss muscular dystrophy.

Emery-Dreifuss muscular dystrophy (EDMD) is characterized by slowly progressive muscle wasting and weakness; early contractures of the elbows, Achilles tendons, and spine; and cardiomyopathy associated with cardiac conduction defects. Clinically indistinguishable X-linked and autosomal forms of EDMD have been described. Mutations in the STA gene, encoding the nuclear envelope protein emerin, are responsible for X-linked EDMD, while mutations in the LMNA gene encoding lamins A and C by alternative splicing have been found in patients with autosomal dominant, autosomal recessive, and sporadic forms of EDMD. We report mutations in LMNA found in four familial and seven sporadic cases of EDMD, including seven novel mutations. Nine missense mutations and two small in-frame deletions were detected distributed throughout the gene. Most mutations (7/11) were detected within the LMNA exons encoding the central rod domain common to both lamins A/C. All of these missense mutations alter residues in the lamin A/C proteins conserved throughout evolution, implying an essential structural and/or functional role of these residues. One severely affected patient possesed two mutations, one specific to lamin A that may modify the phenotype of this patient. Mutations in LMNA were frequently identified among patients with sporadic and familial forms of EDMD. Further studies are needed to identify the factors modifying disease phenotype among patients harboring mutations within lamin A/C and to determine the effect of various mutations on lamin A/C structure and function.

Treatment-seeking women at menopause: a comparison between two university menopause clinics.

OBJECTIVE: We wished to determine the expectations of women about the benefits of hormone replacement therapy (HRT) and how these expectations may be influenced by cultural factors and previous experience of disease by the patient or in their families. DESIGN: The attitudes of patients seeking HRT in Belfast, United Kingdom (n = 218) and Portland, USA (n = 100) were compared at their first clinic attendance using a questionnaire. Physical and mental health issues, previous use of HRT and continuance on treatment were compared. RESULTS: Belfast women were less healthy than their Portland counterparts, with a higher prevalence of cardiovascular disease and psychiatric disorders (p < 0.05). Belfast patients showed a significantly lower continuance with treatment (p < 0.01). Collectively, the patients ranked relief of menopausal symptoms as their main expectation from HRT followed by osteoporosis protection, psychiatric relief and cardioprotection. The Belfast group had higher expectations for the relief of psychological/psychiatric problems (p < 0.01). All women with a family history of cardiac disease or fractures were more concerned for the protective effects of HRT than those women with no relevant family history (p < 0.05). There were cultural difference in expectations from HRT with Belfast women expecting more psychological/psychiatric relief and therefore trying a greater number of preparations. CONCLUSIONS: These findings suggest that menopausal women in both countries are well informed about the potential protective benefits of HRT, and now expect an improvement in the quality of their lives well beyond the relief of menopausal symptoms.

Relationship of anxiety and depression.

There has been considerable controversy regarding the relationship between depression and anxiety. We review briefly the descriptive, longitudinal, genetic, biological, and treatment response data indicating that there is overlap between depression and anxiety. Several possible models are explored that provide different conceptions of how this relationship may best be understood: (1) that there are a variety of more or less discrete, but sometimes coexisting, syndromes within the spectrum of anxiety and depression; (2) that symptoms of depression and anxiety represent different external manifestations of a more basic underlying cause; (3) that one condition may predispose to the other; (4) that the association may be due to artifactual definitional overlap, particularly since the instruments used to measure depression and anxiety share so many items. All these propositions are supported. An important, practical question is discussed--should the mixed anxiety/depressive disorder that has been suggested by ICD-10 be included in DSM-IV?

Comparative analysis of Haemophilus influenzae type b and Escherichia coli J5 lipopolysaccharides.

Haemophilus influenzae type b (HIB) and Escherichia coli J5 (J5) lipopolysaccharides (LPS) were examined to explore the basis of previously observed cross-protection. HIB-LPS and J5-LPS contained ketodeoxyoctonate, glucose, glucoheptose and glucosamine as common carbohydrate moieties, and laurate, myristate, beta-hydroxymyristate and palmitate as common fatty acids, although in different ratios. J5-LPS was five times more lethal than HIB-LPS for chick embryos. Weak serological cross-reactivity was observed by haemagglutination and two-dimensional immunoelectrophoresis. No significant cross-reactivity was demonstrated by enzyme-linked immunosorbent or toxicity-neutralisation assays. The cross-reactivity observed between HIB-LPS and J5-LPS was probably due to common components in the core glycolipid.

An intrauterine insemination-ready cryopreservation method compared with sperm recovery after conventional freezing and post-thaw processing.

OBJECTIVE: To test a sucrose-glycerol cryoprotectant for IUI-ready sperm preparation. DESIGN: Semen aliquots from normozoospermic donors either were subjected to conventional semen freezing (TES and Tris yolk buffer in 7.4% final glycerol) with post-thaw processing or were preprocessed and frozen in HEPES-buffered human tubal fluid with 1% human serum albumin, 4% sucrose, and 6% glycerol. All aliquots were cooled to 4 degrees C, exposed to liquid nitrogen vapors, and stored in liquid nitrogen. Aliquots from each were processed by centrifugation resuspension or by centrifugation in Percoll (Pharmacia, Alameda, CA) before sperm parameters were analyzed. SETTING: University-based andrology laboratory. MAIN OUTCOME MEASURE(S): Recovery of motile sperm. RESULT(S): Percoll processing produced preparations with higher percentages of motile cells; however, cryopreserved sperm had a lower recovery of motile sperm compared with Percoll-processed fresh semen or centrifugation/resuspension-processed fresh or frozen samples. The percentages of sperm with normal morphologies were significantly increased in the IUI-ready samples compared with samples frozen conventionally. The IUI-ready Percoll-processed sample produced the best results, with a final mean motility of 36% and an overall yield of motile sperm of 17.4%. CONCLUSION(S): The sucrose-glycerol-based cryoprotectant produced an IUI-ready preparation with motile sperm recovery comparable to that of conventional semen cryopreservation but with improved percent morphology.

Total antioxidant capacity of seminal plasma is different in fertile and infertile men.

OBJECTIVE: To determine if the total antioxidant capacity of seminal plasma is different in fertile and infertile men. DESIGN: An enhanced chemiluminescence assay applied to seminal plasma from groups of fertile and infertile men. SETTING: The Assisted Conception Unit, Royal Maternity Hospital, Belfast. SUBJECTS: Men of proven fertility whose partners had an ongoing pregnancy resulting from IVF and male partners of couples attending our subfertility clinic. RESULTS: Total antioxidant capacity was significantly higher in seminal plasma from fertile men than from that of infertile men with normozoospermic samples that exhibited reactive oxygen species or asthenozoospermic samples with or without reactive oxygen species activity. CONCLUSIONS: Seminal plasma from infertile men has lower antioxidant levels than that of fertile men, particularly of patients whose semen have poor sperm motility. The presence of reactive oxygen species activity in sperm of infertile groups also is associated with lower levels of chain-breaking antioxidants in seminal plasma.

Differential effects of subcutaneous estrogen and progesterone on low-density lipoprotein size and susceptibility to oxidation in postmenopausal rhesus monkeys.

OBJECTIVE: To study the differential effects of subcutaneous E2 alone or in combination with P on the susceptibility of low-density lipoprotein (LDL) cholesterol to oxidation in naturally postmenopausal diet-controlled rhesus monkeys. DESIGN: Prospective, longitudinal controlled study. SETTING: Oregon Health Sciences University, Portland, Oregon, and Oregon Regional Primate Research Center, Beaverton, Oregon. PATIENT(S): Five naturally postmenopausal rhesus monkeys. INTERVENTION(S): Estradiol was administered subcutaneously for the first 4 weeks, followed by E2 plus P for 4 weeks, followed by a third 4-week washout period. MAIN OUTCOME MEASURE(S): Changes in plasma lipoprotein levels and oxidation of LDL and serum concentrations of E2 and P. RESULT(S): Levels of LDL cholesterol fell after 4 weeks of treatment with E2, compared with baseline. The lag time to half maximal light absorbancy after 4 weeks of E2 treatment was significantly increased compared with baseline. The maximal absorbance values and the slope of the propagation phase after 4 weeks of treatment with E2 were decreased compared with baseline. After 4 weeks of combined E2 and P treatment, all values were comparable to baseline. CONCLUSION(S): These results suggest that subcutaneous E2 therapy appears to enhance LDL resistance to oxidation and that this effect is attenuated by the addition of the P.

Optimizing antibody production in batch hybridoma cell culture.

Optimizing productivity by hybridoma cells relies partly on developing suitable methods for screening and selection of high producing cultures and on understanding regulation of antibody production. In this study, the behavior of hybridoma cells in batch culture was investigated using flow cytometry, and a simple model for antibody production was used to explain production data obtained from these cultures. Surface antibody fluorescence values were found to closely follow the decreasing trend of specific antibody secretion rate over the course of several batch cultures. Therefore, for the hybridoma cell lines studied here (ATCC HB124 and TIB138), surface immunofluorescence levels can be used to select high producing cells as well as to monitor culture productivity. Surface and intracellular antibody fluorescence values were also found to be correlated for cells exhibiting a bimodal distribution with respect to intracellular antibody content. The population of cells containing a bimodal distribution with respect to intracellular antibody content. The population of cells containing lower levels of intracellular antibody was determined to secrete significantly less antibody than the population possessing high intracellular antibody concentrations. Factors which influence antibody production rates and possible strategies for optimizing monoclonal antibody yield are discussed.

Manipulation of heterogeneous hybridoma cultures for overproduction of monoclonal antibodies.

In searching for ways to manipulate heterogeneous hybridoma cell cultures (ATCC HB124) to obtain increased production of monoclonal antibodies (IgG2a), we have selected for a higher secreting but slower growing subpopulation using the level of fluorescent surface-associated antibodies and a fluorescence-activated cell sorter. Cell surface fluorescence was found to be correlated with specific antibody secretion rate over the short term but not with intracellular antibody content. Also, the specific secretion rate of a heterogeneous population of hybridoma cells grown in batch culture has been shown to be inversely correlated with an increase in either the initial cell concentration or the medium antibody concentration. Several experiments suggest that an upper limit exists for medium antibody concentration, above which antibody is degraded at the same rate at which it is produced. Should other cell lines behave similarly, strategies for overproduction of monoclonal antibodies suggested herein could be profitably used in industry.