A spectroscopic investigation of the binding interactions between 4,5-dihydroxyxanthone and heme

In order to investigate one possible mechanism by which xanthones inhibit growth of malaria-causing Plasmodium parasites, optical and NMR spectroscopic studies were performed on a prototypic xanthone, 4,5-dihydroxyxanthone (45X2), upon its complexation to heme. The 45X2 x heme complex stoichiometry in aqueous solution was found to be 1:2; this interaction was non-cooperative, and exhibited a very similar heme complex dissociation constant (K(d)=5.1 x 10(-6)) as observed for the common antimalarial agents, chloroquine and quinine. The 45X2 x heme(2) complex formation was found to be both pH- and solvent-dependent, with clear evidence of the xanthone carbonyl moiety coordinating with the iron of heme. Hydrogen bonding between the hydroxyl groups of 45X2 and the propionate side chains of heme, as well as pi-pi stacking between both aromatic systems appeared to contribute to the overall stability of the 45X2 x heme(2) complex, as judged by 1H NMR. It was concluded that 45X2 forms a complex with a heme dimer in aqueous solution, and that this interaction can be generalized to account for its in vivo detrimental effect of parasite growth through an effective inhibition of hemozoin aggregate formation.

Ontologies of developmental anatomy: their current and future roles

A central problem in current biology is elucidating the molecular networks that drive developmental change and physiological function. Such knowledge is needed partly to understand these networks, partly to be able to manipulate them, and partly to understand and help treat those human congenital abnormalities that arise as a result of mutation. Thus far, bioinformatics technology has been of limited use in this enterprise, mainly because its core focus has been on sequence technology and data archiving. For bioinformatics to be of use in this next tier of investigations, genetic and protein data need to be both archived and searchable by tissue since this is the level at which these networks operate. The resulting databases in turn require ontologies of developmental anatomy that can provide the formal infrastructure for handling gene expression, microarray and other tissue-based data. Here, the progress in making such ontologies, particularly for the developing mouse, is reported and the uses to which they are and will be put, together with the resources and tools currently available for investigating molecular networks and the genetic basis of congenital abnormalities, are considered.

[Does the increasing cesarean section rate reflect a shift in indications or a decline in quality?]

The cesarean section rate is continuously increasing at our department, from 13.8 to 17.2% between 1999 and 2000. The mother's wishes regarding the mode of delivery weigh increasingly on our obstetric decisions. Patient acceptance of elective cesarean section is high, and the increasing cesarean section rate is influenced by paramedical factors. Obstetrics appears to be developing into a mostly surgical discipline. The effect this has on quality (and costs) remains to be seen.

Prognostic factors in surgically treated stage ib-iib cervical carcinomas with special emphasis on the importance of tumor volume

OBJECTIVE

The aim of the study was to analyze the importance of tumor volume as a prognostic factor for overall survival (OS) in surgically treated stage Ib-IIb cervical carcinoma.

METHODS

One hundred thirteen of one hundred sixty-five patients with histopathological stage Ib-IIb cervical carcinoma (44 Ib1, 24 Ib2, 10 IIa, 35 IIb) treated by radical abdominal hysterectomy between 1989 and 1999, for whom tumor volume could be assessed, were included in this study. Of the 113 patients, 90 (79.6%) received postoperative radiotherapy. Measurement of tumor volume was performed on giant histological sections using a semiautomatic image analyzer. The prognostic significance of tumor volume was analyzed and compared with that of various clinicopathological parameters using uni- and multivariate statistics.

RESULTS

The 5-year disease-free survival was 71.4%. Increasing tumor volume was associated with more frequent lymph node metastases and a significant decrease in OS (P = 0.0112). The Median tumor volume was smaller in stage IIa tumors than in stage Ib2 tumors, and histopathological stage did not correlate linearly with lymph node metastases as well as OS. Stage Ib2 tumors were associated with worse overall survival than stage IIa tumors. In univariate analysis, lymph node metastases, histopathological stage, lymph vascular space involvement, tumor volume, parametrial spread, and tumor involvement of resection margins were significant parameters for OS. In multivariate statistical analysis, only lymph node metastases and histopathological staging remained independent prognostic factors for OS.

CONCLUSIONS

Tumor volume does not seem to confer additional prognostic information if histopathological stage and lymph node status are known. However, it may provide important prognostic information if lymph node status is not known or histopathological stage cannot be assessed.

Left ventricular early diastolic inflow velocity and atrial ventricular plane downward velocity: useful parameters to test diastolic function in clinical practice? Diastolic parameters tested in a clinical setting

AIMS

To study the clinical value of the colour-M-mode slope of the early diastolic left ventricular filling phase (Vp) and the early diastolic downward M-mode slope of the left atrioventricular plane displacement (EDS), compared with diastolic function assessed by traditional Doppler evaluation.

METHODS AND RESULTS

In 65 consecutive patients EDS and Vp were compared with a four-degree traditional diastolic function classification, based on pulsed Doppler assessment of the early to atrial transmitral flow ratio (E/A), the E-wave deceleration time (Edt), and the systolic to diastolic (S/D) pulmonary venous inflow ratio. Vp (P=0.006) and EDS (P=0.045) were related to traditional diastolic function (Kruskal--Wallis analysis). EDS showed a trend brake between the moderate and severe diastolic dysfunction groups by traditional Doppler evaluation. Vp and EDS correlated weakly in simple linear regression analysis (r=0.33). Vp and EDS discriminated poorly between normal and highly abnormal diastolic function.

CONCLUSIONS

Vp and EDS were significantly related to diastolic function by traditional Doppler evaluation. They were, however, not useful as single parameters of left ventricular diastolic function due to a small difference between normal and highly abnormal values, allowing for little between-measurement variability. Consequently, these methods for the evaluation of left ventricular diastolic function do not add significantly to traditional Doppler evaluation.

Microinvasive carcinoma of the cervix: site of first focus of invasion

OBJECTIVE

To evaluate the topography of the first invasive focus in microinvasive squamous cell carcinoma of the uterine cervix.

METHODS

We studied 120 formalin-fixed and paraffin-embedded cold-knife conization specimens processed as step-serial sections. Four types of microinvasion were distinguished according to site: type I (ectocervical outside the last cervical gland), type II (ectocervical between the external os and the last gland and in connection with the surface epithelium), type III (ectocervical between the external os and the last gland but deep in cervical glands), and type IV (intracervical and in connection with the surface epithelium).

RESULTS

A total of 142 early invasive foci were seen in the 120 cones. A single focus was seen in 106 (88%) specimens, whereas 14 (12%) had more than one focus. The foci were classified as type I in 16 (11%), type II in 31 (22%), type III in 70 (49%), and type IV in 25 (18%) cases.

CONCLUSION

One half of the early invasive foci originated at the surface epithelium (types I, II, IV), either at the ectocervix (types I, II) or in the endocervix (type IV).

Volume, expansivity and isothermal compressibility changes associated with temperature and pressure unfolding of Staphylococcal nuclease

We have characterized the temperature- and pressure-induced unfolding of staphylococcal nuclease (Snase) using high precision densitometric measurements. The changes in the apparent specific volume, expansion coefficient and isothermal compressibility were determined by these measurements. To our knowledge, these are the first measurements of the volume and isothermal compressibility changes of a protein undergoing pressure-induced unfolding. In order to aid in interpreting the temperature and pressure dependence of the apparent specific volume of Snase, we have also carried out differential scanning calorimetry under the solution conditions which are used for the volumetric studies. We have seen that large compensating volume and compressibility effects accompany the temperature and pressure-induced protein unfolding. Measurements of the apparent specific volume and thermal expansion coefficient of Snase at ambient pressure indicate the formation of a pre-transitional, molten globule type of intermediate structure about 10 degrees C below the actual unfolding temperature of the protein. Compared to the folded state, the apparent specific volume of the unfolded protein is about 0.3-0.5 % smaller. In addition, we investigated the pressure dependence of the apparent specific volume of Snase at a number of different temperatures. At 45 degrees C we calculate a decrease in apparent specific volume due to pressure-induced unfolding of -3.3 10(-3) cm(3) g(-1) or -55 cm(3) mol(-1). The threefold increase in compressibility between 40 and 70 MPa reflects a transition to a partially unfolded state, which is consistent with our results obtained for the radius of gyration of the pressure-denatured state of Snase. At the lower temperature of 35 degrees C, a significant increase in compressibility around 30 MPa is indicative of the formation of a pressure-induced molten globule-like intermediate. Changes in the apparent volume, expansion coefficient and isothermal compressibility are discussed in terms of instrinsic, hydrational and thermal contributions accompanying the unfolding transition.

Grading of Internal Carotid Artery Stenosis: Validation of Doppler/Duplex Ultrasound Criteria and Angiography Against Endarterectomy Specimen

OBJECTIVES

duplex ultrasound has replaced angiography prior to carotid endarterectomy (CEA) in many institutions. However, the indications for CEA are based on angiographically controlled studies and widely accepted ultrasound criteria do not exist. Consequently, the reliability of Doppler and/or duplex ultrasound to predict a high-grade ICA stenosis has to be proven.

DESIGN

prospective validation study.

MATERIALS

one hundred and fifty carotid bifurcations assessed by ultrasound and selective angiography and 68 acrylat outcasts of carotid specimen after eversion CEA.

METHODS

ICA stenosis was measured angiographically according to the ECST criteria. Combined Doppler acoustic standard criteria (CDASC), peak systolic frequency (PSF), peak systolic velocity (PSV) and end-diastolic velocity (EDV) served as criteria for the ultrasound assessment. These criteria and the results of angiography were compared to the degree of ICA stenosis determined by specimen measurements.

RESULTS

the median degree of ICA stenosis as assessed by angiography (82%, range 56-97%) and CDASC (83%, range 50-99%) corresponded well to the specimen measurements (80%, range 50-95%). The sensitivity of angiography and CDASC to predict a 70-90% ICA stenosis (ECST criteria) compared to the specimen measurements was 88% and 95%, respectively. The positive predictive value (PPV) reached 92% and 96%, respectively. CDASC were equivalent to angiography and were superior to the best single frequency or velocity parameters. If CDASC do not indicate a >/=70% ICA stenosis in spite of a PSV >/=180 cm/s and/or an EDV >/=50 cm/s, angiography may detect patients with a >70% ICA stenosis.

CONCLUSIONS

CDASC are valid in the quantification of high-grade ICA stenosis. They are more reliable than single velocity and/or frequency measurements. However, if velocity criteria and CDASC do not agree, angiography should be performed.

Pressure-jump small-angle x-ray scattering detected kinetics of staphylococcal nuclease folding

The kinetics of chain disruption and collapse of staphylococcal nuclease after positive or negative pressure jumps was monitored by real-time small-angle x-ray scattering under pressure. We used this method to probe the overall conformation of the protein by measuring its radius of gyration and pair-distance-distribution function p(r) which are sensitive to the spatial extent and shape of the particle. At all pressures and temperatures tested, the relaxation profiles were well described by a single exponential function. No fast collapse was observed, indicating that the rate limiting step for chain collapse is the same as that for secondary and tertiary structure formation. Whereas refolding at low pressures occurred in a few seconds, at high pressures the relaxation was quite slow, approximately 1 h, due to a large positive activation volume for the rate-limiting step for chain collapse. A large increase in the system volume upon folding implies significant dehydration of the transition state and a high degree of similarity in terms of the packing density between the native and transition states in this system. This study of the time-dependence of the tertiary structure in pressure-induced folding/unfolding reactions demonstrates that novel information about the nature of protein folding transitions and transition states can be obtained from a combination of small-angle x-ray scattering using high intensity synchrotron radiation with the high pressure perturbation technique.

Cervical intraepithelial neoplasia III: long-term outcome after cold-knife conization with clear margins

OBJECTIVE

To evaluate the long-term outcome of patients with severe cervical intraepithelial neoplasia or squamous cell carcinoma in situ (CIN III) after cold-knife conization with clear margins.

METHODS

A total of 4417 women (mean age 36, range 18-72 years) with histologically confirmed CIN III had cold-knife conization with clear margins at our institution between 1970 and 1994. All patients were followed up with colposcopy, cytology, and pelvic examination for a mean of 18 years (range 5-30years).

RESULTS

New high-grade squamous intraepithelial lesions (SILs) (CIN II and III) developed in 15 (0.35%) patients (mean age 35, range 25-65 years) after a median of 107 (range 40-201) months. A total of 4402 (99.65%) patients (mean age 36, range 18-72 years) were free of high-grade SILs after a mean follow-up of 18 (range 5-30) years. High-grade glandular intraepithelial lesions developed in two (0.05%) patients 14 and 17 years after conization. Twelve (0.3%) patients had metachronous vulvar intraepithelial neoplasia (VIN) grade III or vaginal intraepithelial neoplasia (VAIN) grade III, and one (0.02%) patient had invasive vaginal carcinoma 10 years after conization.

CONCLUSION

Cold-knife conization with clear margins was an adequate method to definitively treat CIN III.

Impaired whole-blood polymorphonuclear leukocyte migration as a possible predictive marker for infections in preterm premature rupture of membranes

OBJECTIVES

Steroids, used in preterm premature rupture of membranes (pPROM), to reduce the risk of morbidity and mortality of the preterm neonate, impair the maternal polymorphonuclear leukocyte (PMN)-based immune system. In spite of combination with antibiotics, prenatal and postnatal bacterial infections of mother and child are frequent. This pilot study focuses on the influence of steroids in pPROM on maternal PMN functional capacity and subsequent infections.

METHODS

After opting for expectant management, eight women with pPROM and no signs of infection were treated by steroids (betamethasone 5.7 mg, i.m. every 24 hours, for three days) and antibiotic therapy with either amoxicillin and clavulanic acid, piperacillin or ampicillin i.v. up to delivery. The conventional inflammation parameters of PMN blood count and C-reactive protein (CRP) were measured daily in parallel with PMN migratory capacity towards N-formyl-methionyl-leucyl-phenylalanine stimulation and under blank conditions, estimated by a whole blood membrane filter assay.

RESULTS

In all patients PMN migration decreased during the application of steroids. Three patients showed a decrease in PMN migration below critical values and in spite of antibiotic prophylaxis acute pyelonephritis developed 2-6 days later. PMN count and CRP were not predictive of maternal infection.

CONCLUSION

Reduced PMN function, caused by steroid treatment in pPROM, is suggested to be a reason for serious bacterial infections in spite of antibiotic prophylaxis. PMN migration reflects individual PMN defensive capacity.

Kolposkopie der CIN und des mikroinvasivenZervixkarzinoms

The colposcopist must distinguish between two patterns: nonsuspicious findings and suspicious findings. With experience, the colposcopist will succeed more and more in distinguishing between the two, thereby markedly reducing the number of biopsies. Suspicious findings are not synonymous with abnormal findings because the latter are not always due to premalignant lesions. A number of features are of value in the different diagnosis of colposcopic findings: sharp borders, response to acetic acid (white epithelium), surface contour, appearance of blood vessels, surface extent (size), combinations of abnormalities, iodine uptake, and keratinization. The diagnostic features described above can be expressed to varying degrees, and can be found singly or in combination. The more distinct a feature is and the greater the variety of features seen in combination, the higher the index of suspicion. Attempting to differentiate between the various grades of CIN (SIL) colposcopically is more questionable, as these lesions are regarded now as forming a spectrum of the same biologic process.

Acute medical emergencies: the physician's role

Medical emergencies are an important and growing component of medical practice. The past 6 years have seen a year-on-year annual growth of 4.4% in non-elective admissions. Thus, in 1992–3, 3 577 266 patients were admitted to acute hospital beds, a number that rose in 1998–9 to 4 642 382 (excluding psychiatry and maternity) (NHS Executive, 2000).

NMR study of translational and rotational dynamics in monoolein-water mesophases: obstruction and hydration effects

Using a variety of NMR methods (magnetic field gradient echo decays, 2H one- and two-dimensional spectra, spin-lattice relaxation rates), both translational and rotational dynamics of the constituents of monoolein MO/H(2)O mesophases have been studied. The experiments lead to the following conclusions. The translational dynamics of the lipid molecules is essentially dominated by obstruction effects due to the topologies of the diverse mesophases. On the other hand, water dynamics-in the regime of small water concentrations-is strongly influenced by hydration of the lipid head groups. Hydration is seen in diffusion data, in spectra and in spin-lattice relaxation of the water molecules. This work represents an involved extension of our recently published work [Chem. Phys. Lipids 106, 115 (2000)].

Minimal invasive decompression of the orbit in Graves' orbitopathy

BACKGROUND

Surgical decompresssion of the orbit may be considered as a suitable form of therapy if, as a result of the increased volume inside the orbit, there are motility disorders such as diplopia or a progressive decrease in visual acuity. In view of the fact that this operation will not cure the underlying disease, the treatment should be as mild as possible.

METHODS

In five subjects with Graves' orbitopathy we managed to extend the volume of the intraconal orbit by microsurgical liposuction. We carried out a lateral canthotomy to approach the orbit behind the globe. After decompression of the soft tissue, the lateral palpebral ligaments were refixed. To assess the scale of the functional rehabilitation we compared preoperative parameters (visual acuity, Hertel's index, visual field, motility) with the postoperative results.

RESULTS

In all cases we found a significant improvement of position and motility without signs of diplopia. There was a postoperative increase in the visual field and visual acuity was 0.4 and the protusion of the globe could be decreased by 3-6 mm (Hertel's index). Furthermore, the ocular hypertension we found preoperatively could no longer be detected after the operation.

CONCLUSIONS

Microsurgical decompression of the soft tissue via an approach from behind the globe proved to be a very gentle alternative to conventional methods of orbital decompression because of the satisfying functional and esthetic rehabilitation in selected cases.

RhD genotyping by quantitative fluorescent polymerase chain reaction: a new approach

OBJECTIVE

To develop a new method of RhD/d genotype determination using a quantitative fluorescent PCR (QF-PCR) assay.

METHODS

Polymerase chain reaction amplification (PCR) of fragments of exon 7 of both the RHD and RHCE genes was performed from 32 amniotic fluid and 26 chorionic villus samples known to be heterozygous for the RHD gene, 74 peripheral blood samples of RhD-positive blood donors (homozygous or heterozygous) estimated by serologic typing and 24 RhD-negative fetal samples. The number of copies of the RHD gene in RhD-positive samples was determined by comparing the fluorescent intensities of the amplification products specific for the RHD and the RHCE genes.

RESULTS

A ratio of fluorescent intensities of 1:1 clearly indicated D/D homozygous individuals whereas a ratio of 1:2 was demonstrated in samples from D/d heterozygous individuals. The mean fluorescent intensity ratio of the peak areas of homozygous samples was 1.12 (SD 0.128), the mean ratio of the peak areas of heterozygous samples was 0.51 (SD 0.060). Complete agreement was obtained between RhD/d typing by QF-PCR and RhD genotypes assessed by family studies and serological methods.

CONCLUSIONS

The fluorescent PCR-based DNA test allows easy, rapid and accurate determination of the zygosity for the RHD gene. This new technique provides useful information for the clinical management of pregnancies of sensitised RhD-negative mothers.

Impact of transportation on short-term preserved corneas preserved in Optisol-GS, Likorol, Likorol-DX, and MK-medium

PURPOSE

To investigate the impact of transportation, simulated under laboratory conditions, on the corneal endothelium preserved by Optisol-GS, Likorol-DX, Likorol, and MK-Medium.

METHODS

Three hundred twenty corneas from freshly slaughtered pigs were stored in Optisol-GS. Likorol-DX, Likorol. and MK-Medium for 1, 3, 6, or 10 days. After short-term preservation, the transportation was simulated on a laboratory shaker at 4 degrees C with an acceleration of 0-100 km/h in 16 seconds for 5 hours. Mate corneas served as the control. Corneal endothelial cell density was determined at the time of dissection, directly before the experiment, and after subsequent organ culture.

RESULTS

A significant cell loss induced by transportation simulation was not observed in any experimental group. Preservation in MK-Medium starting at 3 days of short-term preservation resulted in a significant cell loss. Storage for up to 6 days in Optisol-GS, Likorol-DX, and Likorol did not result in a significant decrease in cell density.

CONCLUSION

Short-term preserved corneas can be routinely distributed without a reevaluation, if the tissue is preserved for a shorter time as recommended by the manufacturers.

[Cervical cancer in pregnancy--practical recommendations]

Five-year survival did not differ between 20 pregnant women and 541 patients with invasive cervical cancer treated with radical surgery at the Department of Obstetrics and Gynecology of the University of Graz. Therapeutic recommendations are given. In stage Ib to IIb disease, surgery is recommended postpartum following the induction of fetal lung maturity if fertility should be preserved and if the cancer is diagnosed after the 20th week of pregnancy. The same is recommended in stage Ia independent of the duration of gestation. In advanced disease (stage IIIb to IVb) definite therapy should be applied immediately after diagnosis. If cervical intraepithelial neoplasia grade III is suspected, colposcopy, cytology and biopsy are mandatory. Definite therapy should be performed 6 weeks postpartum.