Facilitating children's in-session involvement in child and family therapies: A dynamic framework of clinical practices

Children's in-session involvement in child and family therapies correlates with both positive and negative treatment outcomes. Thus, it is important to gain a better understanding of the clinical practices that facilitate children's involvement in therapy sessions so that practitioners can employ them with greater precision. To address this need, we conducted a study to answer the following question: What clinical practices facilitate children's in-session involvement in child and family therapies? The data consisted of 16 extant audiovisual recordings of child and family therapy sessions and 24 stimulated-recall interviews with the participants in the recordings. Following constructivist grounded theory and incorporating storyline as an additional analytical technique, we have constructed a framework consisting of four involvement-enhancing practices: managing time, staying relevant, adjusting intensity, and facilitating inclusion. Furthermore, by detailing some of the complex processes that practitioners navigate when they facilitate children's involvement, our study adds a multilayered and dynamic dimension to the list of already established involvement facilitators. It may be used to moderate an overstandardized work culture that continues to characterize services that address children's needs. The results may be applied to other institutional encounters, providing resonance beyond the analyzed therapy sessions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Dental hygienists and dentists as providers of brush biopsies for oral mucosa screening

BACKGROUND

Oral cancer is a severe and potentially fatal disease usually starting in the squamous epithelium lining the oral cavity. Together with oropharyngeal carcinoma, it is the fifth to sixth most common malignancy worldwide. To limit the increase in the global oral cancer incidence over the past two decades, the World Health Assembly adopted a resolution urging member states to integrate preventive measures such as engagement and training of dental personnel in screening, early diagnosis, and treatment into their national cancer control programs.

AIM

The aim of this study was to investigate if dental hygienists (DHs) and dentists (Ds) in general dental practice care can be entrusted to perform brush sampling of oral potentially malignant disorders (OPMDs), and to evaluate their level of comfort in performing brush biopsies.

METHODS

Participants were five DHs and five Ds who received one day of theoretical and clinical training in oral pathology to identify OPMDs (leukoplakia [LP], erythroplakia [EP], and oral lichen planus [OLP]), and perform brush sampling for PAP cytology and high-risk human papillomavirus (hrHPV) analysis.

RESULTS

Out of 222 collected samples, 215 were adequate for morphological assessment and hrHPV analysis. All the participants agreed that sample collection can be incorporated in DHs and Ds routine clinical duties, and most of them reported that sample collection and processing was easy/quite easy.

CONCLUSION

Dentists and DHs are capable of collecting satisfactory material for cytology and hrHPV analysis. All the participating DHs and Ds were of the opinion that brush sampling could be handled routinely by DHs and Ds in GDP.

The Effect of Domiciliary Professional Oral Care on Root Caries Progression in Care-Dependent Older Adults: A Systematic Review

With care dependency, untreated root caries lesions (RCLs) and irregular dental visits are common. RCLs, if left untreated, could lead to pain, tooth loss, difficulties eating, and impact on general health. Therefore, there is a need for prevention and effective treatment for RCLs, and especially in those with care dependency. The aim of this systematic review was to investigate the effect of domiciliary professional oral care on root caries development and progression, in comparison with self-performed or nurse-assisted oral care. A literature search was conducted in four databases in November 2022. Two authors independently screened the literature throughout the review process. Five of the identified studies were found to be relevant. Four of these were assessed as having moderate risk of bias and were included in the review, while one study had high risk of bias and was excluded from further analyses. Due to heterogenicity of the included studies (and of the interventions and outcomes), no meta-analysis or synthesis without meta-analysis (SWiM) was performed. The participation of dental personnel performing mechanical plaque removal and fluoride, or chlorhexidine application seems beneficial for care-dependent older adults with risk of RCLs development and progression. However, future studies are needed.

Oral health care beliefs among care personnel working with older people - follow up of oral care education provided by dental hygienists

Objectives

The proportion of older people in the population is increasing rapidly. Along with this comes an increase in the number of people requiring assistance in daily living, including oral care. Swedish law stipulates that care personnel who work with older people should be offered oral health education every year. The aim of this study was to investigate oral health care beliefs among such personnel.

Methods

A questionnaire study was conducted among 2167 personnel providing care to older people at special accommodation sites and in home care. Data were collected using the Nursing Dental Coping Beliefs Scale. Descriptive statistics were calculated and logistic regression analysis was performed.

Results

Personnel working in home care had lower odds of having an internal locus of control than those working in special accommodation, and personnel with less than 10 years of working experience had lower odds than their more experienced counterparts. Men had higher odds of having an external locus of control than women.

Conclusions

It seems important to ensure that home care personnel and less experienced personnel attend oral care educational sessions, and to encourage male staff to focus on oral care work.

'Periodontal health and disease in an older population: A 10-year longitudinal study'

OBJECTIVES

To investigate alveolar bone loss (ABL), which is an indicator of periodontitis, and to identify risk factors for ABL in an older population between 2008 and 2018.

METHODS

This longitudinal study used data from a questionnaire survey and a clinical examination administered on two occasions ten years apart to 273 individuals who were 65 years and 75 years in 2008.

RESULTS

The mean number of teeth decreased significantly over the ten-year study period, while the proportion of individuals with calculus and moderate ABL visible on radiographs increased. For both ages, the number of teeth decreased by a mean of 2 teeth. The proportions of participants reporting poor general health, daily medication, xerostomia, living singly, visiting dental care irregularly and being in need of extra support in their homes all increased over the observation period.

CONCLUSIONS

Despite an increased progression of moderate alveolar bone loss, a fairly good dentition and chewing capacity was retained in this older population. However, the individual's age and fragility are important indicators that need to be considered when planning oral health care and the availability of dental care.

'Caries disease among an elderly population-A 10-year longitudinal study'

OBJECTIVES

To investigate the prevalence of dental caries and to identify risk factors for dental caries in an elderly population between 2008 and 2018.

METHODS

This longitudinal study used data from a questionnaire survey and a clinical examination administered on two occasions 10 years apart to 273 individuals who were 65 and 75 years of age in 2008. The variables included were prevalence of dental caries as well as socioeconomic and socio-behavioural factors.

RESULTS

The number of teeth decreased in both age groups by a mean of 2 over the 10-year study period, but the prevalence of dental caries remained stable. Approximately, a quarter of the participants had caries lesions. Toothbrushing once a day or less was the factor most strongly correlated with dental caries lesions (OR: 3.82, 95% CI: 1.68-8.66, p = 0.001), followed by need for homecare (OR: 3.50, 95% CI: 1.55-7.93, p = 0.003) and interproximal cleaning less than once a day (OR: 2.65, 95% CI: 1.36-5.19, p = 0.004).

CONCLUSIONS

This longitudinal study revealed no increase in the prevalence of dental caries lesions, indicating that good oral health can be preserved among elderly people. The highest risk for dental caries lesions was among participants with inadequate oral hygiene routines (toothbrushing once a day or less and seldom using interproximal devices) and in need of help in daily living, emphasizing the importance of oral hygiene and collaboration between dental services and community-based health care.

Dynamic allosteric communication pathway directing differential activation of the glucocorticoid receptor

Allosteric communication within proteins is a hallmark of biochemical signaling, but the dynamic transmission pathways remain poorly characterized. We combined NMR spectroscopy and surface plasmon resonance to reveal these pathways and quantify their energetics in the glucocorticoid receptor, a transcriptional regulator controlling development, metabolism, and immune response. Our results delineate a dynamic communication network of residues linking the ligand-binding pocket to the activation function-2 interface, where helix 12, a switch for transcriptional activation, exhibits ligand- and coregulator-dependent dynamics coupled to graded activation. The allosteric free energy responds to variations in ligand structure: subtle changes gradually tune allostery while preserving the transmission pathway, whereas substitution of the entire pharmacophore leads to divergent allosteric control by apparently rewiring the communication network. Our results provide key insights that should aid in the design of mechanistically differentiated ligands.

Influence of smoking on periodontal healing one year after active treatment

OBJECTIVE

To investigate the impact of smoking on the reduction of pockets >4 mm deep and a composite variable of residual pockets >4 mm and bleeding on probing (BoP) after treatment.

METHODS

Eligible after exclusion due to missing records were 3,535 individuals, referred for periodontal treatment between 1980 and 2015. The number of teeth (NT), probing pocket depth (PPD), proportion of plaque (PLI) and BoP were registered before treatment and 1 year after treatment. To analyse the impact of smoking on PPD reduction, a mixed model adjusted for age, sex, type of therapy, baseline PPD, reduction of PLI, BoP and NT was used. Depending on residual PPD and BoP, two categories were created: good and poor responders.

RESULTS

PLI was reduced by 20% in non-smokers and by 18% in smokers, and BoP by 46% and 37%, respectively. In the adjusted mixed model, the mean reduction of PPD > 4 mm among smokers undergoing surgery was 14.4 versus 9.7 in non-smokers (p < .001). The odds ratio for being a poor responder was 2.40 (95% CI 1.99-2.91, p < .001) for smokers.

CONCLUSION

Although surgical treatment reduced PPD >4 mm in smokers more effectively than in non-smokers, significantly more non-smokers were good responders after periodontal therapy.

Prevalence of dental caries and influencing factors, time trends over a 30-year period in an adult population. Epidemiological studies between 1983 and 2013 in the county of Dalarna, Sweden

OBJECTIVE

The aim of this study was to investigate the prevalence of dental caries in an adult population using four different cross-sectional studies over a 30-year period and to assess its possible associations with socio-economic and socio-behavioural factors.

MATERIALS AND METHODS

Four cross-sectional epidemiological studies were performed in the county of Dalarna, Sweden, in 1983, 2003, 2008 and 2013. Random samples of 1012-2244 individuals, aged 20-85 years, who answered a questionnaire about socio-economic and socio-behavioural factors, were radiographically and clinically examined.

RESULTS

The proportion of individuals with at least one decayed surface (DS) was 58% in 1983 and significantly lower, 34% in 2008 (p < 0.05) and 33% in 2013; the mean number of DS was 2.0 in 1983 and 1.1 in 2013 in the age group 35-75 (p < 0.05). In the age group 85, the mean number of DS was 1.2 in 2008 and 2.4 in 2013. Adjusted for age and number of teeth, irregular dental visits, limited financial resources for dental care, smoking, education below university, male gender, daily medication and single living were positively and statistically associated with manifest caries.

CONCLUSION

The declining trend in the prevalence of manifest caries seems to be broken. In the oldest age group mean number of DS was higher in 2013 compared with 2008, indicating a possible beginning of an increase. This needs special attention as this group increases in the population, retaining natural teeth high up in age. Manifest caries was found to be associated with socio-economic and socio-behavioural factors.

Improved replication efficiency of echovirus 5 after transfection of colon cancer cells using an authentic 5' RNA genome end methodology

Oncolytic virotherapy is a promising novel form of cancer treatment, but the therapeutic efficiency needs improvement. A potential strategy to enhance the therapeutic effect of oncolytic viruses is to use infectious nucleic acid as therapeutic agent to initiate an oncolytic infection, without administrating infectious viral particles. Here we demonstrate improved viral replication activation efficiency when transfecting cells with 5' end authentic in vitro transcribed enterovirus RNA as compared to genomic RNA with additional non-genomic 5' nucleotides generated by conventional cloning methods. We used echovirus 5 (E5) as an oncolytoc model virus due to its ability to replicate in and completely destroy five out of six colon cancer cell lines and kill artificial colon cancer tumors (HT29 spheroids), as shown here. An E5 infectious cDNA clone including a hammerhead ribozyme sequence was used to generate in vitro transcripts with native 5' genome ends. In HT29 cells, activation of virus replication is approximately 20-fold more efficient for virus genome transcripts with native 5' genome ends compared to E5 transcripts generated from a standard cDNA clone. This replication advantage remains when viral progeny release starts by cellular lysis 22 h post transfection. Hence, a native 5' genomic end improves infection activation efficacy of infectious nucleic acid, potentially enhancing its therapeutic effect when used for cancer treatment. The clone design with a hammerhead ribozyme is likely to be applicable to a variety of oncolytic positive sense RNA viruses for the purpose of improving the efficacy of oncolytic virotherapy.

Cytotoxic effect and uptake of estramustine in a rat glioma model

The cytotoxic effect of estramustine-phosphate (EMP) and the uptake in tumor tissue were investigated in a rat glioma model in vitro and in vivo. EMP, a combination of nornitrogen mustard and 17beta-estradiol, is a cytotoxic drug which main target is assumed to be the microtubule system. EMP and its metabolite estramustine (EaM) have a demonstrated anti-tumorous effect on human glioma cells in vitro. The drug uptake in tumor tissue and subsequently also the cytotoxic effect, is believed to depend, at least partially, on a specific estramustine-binding protein (EMBP) which is present in human glioma tissue. In this study we have examined the effects and pharmacokinetics of EaM in the nitrosourea induced BT4C rat glioma model. The tumor was characterized by infiltrative growth with a histopathological picture resembling gliosarcoma. The presence of EMBP was demonstrated by immunohistology. In vitro EMP caused a dose-related inhibition of BT4C-cell growth. In vivo, in the rat model, a significant inhibition of tumor growth was obtained after administration of EaM 20 mg/kg/d i.p. The pharmacokinetics of EaM resembled that found in the human clinical situation with EaM as the main metabolite accumulating in tumor tissue. The mean concentration ratio of EaM was 15.6 in tumor versus serum, and 1.8 in tumor versus normal brain of 1.8. The cytotoxic effect demonstrated in the rat glioma model justifies further evaluation of EMP/EaM in the treatment of malignant gliomas.

Comparison of oral status in an adult population 35-75 year of age in the county of Dalarna, Sweden in 1983 and 2008

The aim was to study the prevalence and distribution of number of teeth, number of intact and decayed teeth and prevalence and distribution of removable dentures and periodontal disease over 25 years 1983-2008. Two cross-sectional studies (EpiWux) were performed in the County of Dalarna, Sweden in 1983 and 2008. In the 1983 study a random sample of 1012 individuals were invited to participate in this epidemiological and clinical study and 1440 individuals in 2008. A total number of 1695 individuals, stratified into geographical areas (rural and urban areas), in the age groups 35, 50, 65 and 75 answered a questionnaire and were also clinically and radiographically examined.The number of edentulous individuals decreased from 15% in 1983 to 3% in 2008. Number of teeth increased from 22.7 in 1983 to 24.2 in 2008 and decayed surfaces per tooth showed a three-time reduction over this period of time. As a consequence of better oral status the prevalence of complete removable dentures in both jaws decreased from 15% in 1983 to 2% in 2008. Individuals with moderate periodontitis decreased from 45% in 1983 to 16% in 2008.

CONCLUSION

Covering a period of 25 years the present study can report dramatic improvements in all aspects of dental status that were investigated.This is encouraging for dental care professionals, but will not necessarily lead to less demand for dental care in the future as the population is aging with a substantial increase in number of teeth.

Extensive polymorphism in the porcine Toll-like receptor 10 gene

The great importance of the Toll-like receptors (TLRs) in innate immunity is well established, but one family member--TLR10--remains elusive. TLR10 is expressed in various tissues in several species, but its ligand is not known and its function is still poorly understood. The open reading frame of TLR10 was sequenced in 15 wild boars, representing three populations, and in 15 unrelated domestic pigs of Hampshire, Landrace and Large White origin. Amino acid positions corresponding to detected nonsynonymous single nucleotide polymorphisms (SNPs) were analysed in the crystal structures determined for the human TLR1-TLR2-lipopeptide complex and the human TLR10 Toll/Interleukin 1 receptor (TIR) dimer. SNP occurrence in wild boars and domestic pigs was compared, and haplotypes for the TLR10 gene and the TLR6-1-10 gene cluster were reconstructed. Despite the limited number of animals sequenced in the present study (N = 30), a larger number of SNPs were found in TLR10 than recently reported for TLR1, TLR6 and TLR2. Thirty-three SNPs were detected, of which 20 were nonsynonymous. The relative frequency of nonsynonymous (d(N) ) and synonymous (d(S) ) SNPs between wild boars and domestic pigs was higher in TLR10 than recently reported for TLR1, TLR6 and TLR2. However, the polymorphism reported in the present study seems to leave the function of the TLR10 molecule unaffected. Furthermore, no nonsynonymous SNPs were detected in the part of the gene corresponding to the hinge region of the receptor, probably reflecting rigorously acting functional constraint. The total number of SNPs and the number of nonsynonymous SNPs were significantly lower (P < 0.05) in the wild boars than in the domestic pigs, and fewer TLR10 haplotypes were present in the wild boars. The majority of the TLR6-1-10 haplotypes were specific for either wild boars or domestic pigs, probably reflecting differences in microbial environment and population history.

Exposure assessment to alpha- and beta-pinene, delta(3)-carene and wood dust in industrial production of wood pellets

The main aim of the study was to measure the exposure to monoterpenes (alpha- and beta-pinene and Delta(3)-carene) and wood dust during industrial production of wood pellets and briquettes. Additional aims were to compare the results from wood dust sampled on a filter with real time measurements using a direct reading instrument and to identify peak exposures to dust. Twenty-four men working at six companies involved in industrial production of wood pellets and briquettes participated in the study. Monoterpenes were measured by diffusive sampling and wood dust was measured as total dust. A data logger (DataRAM) was used for continuous monitoring of dust concentration for 18 of the participants. The sampling time was approximately 8 h. The personal exposure to monoterpenes ranged from 0.64 to 28 mg/m(3) and a statistically significant (Kruskal-Wallis test, P = 0.0002) difference in levels of monoterpenes for workers at different companies was seen. In the companies the personal exposure to wood dust varied between 0.16 and 19 mg/m(3) and for 10 participants the levels exceeded the present Swedish occupational exposure limit (OEL) of 2 mg/m(3). The levels of wood dust during the morning shift were significantly (Mann-Whitney test, P = 0.04) higher compared with the afternoon shift. Continuous registration of dust concentration showed peak values for several working operations, especially cleaning of truck engines with compressed air. For 24 workers in six companies involved in industrial production of wood pellets the personal exposure to monoterpenes was low and to wood dust high compared with the present Swedish OEL and previous studies in Swedish wood industries. Since the DataRAM can identify critical working tasks with high wood dust exposure a reduction in exposure levels could probably be achieved by changes in working routines and by the use of protective equipment.

Spectroscopic characterization of bacteriorhodopsin's L-intermediate in 3D crystals cooled to 170 K

Spectra are presented from a single 3D microcrystal of bacteriorhodopsin (bR) cooled to 170 K under various illumination conditions. This set is necessary and sufficient to assign the relevant crystal reference spectra. A spectral decomposition of the difference spectrum obtained following the trapping protocol of Royant et al. (2000) (Nature 406, 645-648) is given, confirming that the low temperature L-intermediate was the species that dominated the structural rearrangements previously reported. Smaller contributions from the K and M spectral intermediates are also quantified. Mechanistic insights derived from the X-ray structures of the early bR intermediates are discussed.

X-ray structure of sensory rhodopsin II at 2.1-A resolution

Sensory rhodopsins (SRs) belong to a subfamily of heptahelical transmembrane proteins containing a retinal chromophore. These photoreceptors mediate the cascade of vision in animal eyes and phototaxis in archaebacteria and unicellular flagellated algae. Signal transduction by these photoreceptors occurs by means of transducer proteins. The two archaebacterial sensory rhodopsins SRI and SRII are coupled to the membrane-bound HtrI and HtrII transducer proteins. Activation of these proteins initiates phosphorylation cascades that modulate the flagellar motors, resulting in either attractant (SRI) or repellent (SRII) phototaxis. In addition, transducer-free SRI and SRII were shown to operate as proton pumps, analogous to bacteriorhodopsin. Here, we present the x-ray structure of SRII from Natronobacterium pharaonis (pSRII) at 2.1-A resolution, revealing a unique molecular architecture of the retinal-binding pocket. In particular, the structure of pSRII exhibits a largely unbent conformation of the retinal (as compared with bacteriorhodopsin and halorhodopsin), a hydroxyl group of Thr-204 in the vicinity of the Schiff base, and an outward orientation of the guanidinium group of Arg-72. Furthermore, the structure reveals a putative chloride ion that is coupled to the Schiff base by means of a hydrogen-bond network and a unique, positively charged surface patch for a probable interaction with HtrII. The high-resolution structure of pSRII provides a structural basis to elucidate the mechanisms of phototransduction and color tuning.

X-ray snapshots of serine protease catalysis reveal a tetrahedral intermediate

Studies on the catalytic mechanism and inhibition of serine proteases are widely used as paradigms for teaching enzyme catalysis. Ground-breaking work on the structures of chymotrypsin and subtilisin led to the idea of a conserved catalytic triad formed by the active site Ser, His and Asp residues. An oxyanion hole, consisting of the peptide amide of the active site serine and a neighbouring glycine, was identified, and hydrogen bonding in the oxyanion hole was suggested to stabilize the two proposed tetrahedral intermediates on the catalytic pathway. Here we show electron density changes consistent with the formation of a tetrahedral intermediate during the hydrolysis of an acyl-enzyme complex formed between a natural heptapeptide and elastase. No electron density for an enzyme-product complex was observed. The structures also suggest a mechanism for the synchronization of hydrolysis and peptide release triggered by the conversion of the sp2 hybridized carbonyl carbon to an sp3 carbon in the tetrahedral intermediate. This affects the location of the peptide in the active site cleft, triggering the collapse of a hydrogen bonding network between the peptide and the beta-sheet of the active site.

Analyzing protein functions in four dimensions

Time-resolved structural studies on biomolecular function are coming of age. Focus has shifted from studies on 'systems of opportunities' to a more problem-oriented approach, addressing significant questions in biology and chemistry. An important step in this direction has been the use of physical and chemical trapping methods to capture and then freeze reaction intermediates in crystals. Subsequent monochromatic data collection at cryogenic temperatures can produce high resolution structures of otherwise elusive intermediates. The combination of diffraction methods with spectroscopic techniques provides a means to directly correlate electronic transitions with structural transitions in the sample, eliminating much of the guesswork from experiments. Studies on cytochrome P450, isopenicillin N synthase, cytochrome cd1 nitrite reductase, copper amine oxidase and bacteriorhodopsin were selected as examples, and the results are discussed.

Helix deformation is coupled to vectorial proton transport in the photocycle of bacteriorhodopsin

A wide variety of mechanisms are used to generate a proton-motive potential across cell membranes, a function lying at the heart of bioenergetics. Bacteriorhodopsin, the simplest known proton pump, provides a paradigm for understanding this process. Here we report, at 2.1 A resolution, the structural changes in bacteriorhodopsin immediately preceding the primary proton transfer event in its photocycle. The early structural rearrangements propagate from the protein's core towards the extracellular surface, disrupting the network of hydrogen-bonded water molecules that stabilizes helix C in the ground state. Concomitantly, a bend of this helix enables the negatively charged primary proton acceptor, Asp 85, to approach closer to the positively charged primary proton donor, the Schiff base. The primary proton transfer event would then neutralize these two groups, cancelling their electrostatic attraction and facilitating a relaxation of helix C to a less strained geometry. Reprotonation of the Schiff base by Asp 85 would thereby be impeded, ensuring vectorial proton transport. Structural rearrangements also occur near the protein's surface, aiding proton release to the extracellular medium.

Determination of estramustine phosphate and its metabolites estromustine, estramustine, estrone and estradiol in human plasma by liquid chromatography with fluorescence detection and gas chromatography with nitrogen-phosphorus and mass spectrometric detection

Bioanalytical methods for the determination of estramustine phosphate by liquid chromatography and its four main metabolites estromustine, estramustine, estrone and estradiol by gas chromatography are described. For the estramustine phosphate assay the plasma was purified by protein precipitation followed by a C18 solid-phase extraction. For the metabolite assay the plasma samples were purified by a C18 solid-phase and liquid-liquid extraction procedure and derivatised by silanization. Thereafter, estramustine and estromustine were quantified by gas chromatography with nitrogen-phosphorus detection and estradiol and estrone were quantified by gas chromatography with selected ion monitoring. The methods were validated with respect to linearity, selectivity, precision, accuracy, limit of quantitation, limit of detection, recovery and stability. The limit of quantitation was 2.3 micromol/l for estramustine phosphate, 30 nmol/l for estromustine and estramustine, 12 nmol/l for estrone and 8 nmol/l for estradiol. The results showed good precision and accuracy for estramustine phosphate and the four metabolites. The intermediate precision was 6.2-13.5% (C.V.) and the accuracy was 91.8-103.9%.

High-resolution X-ray structure of an early intermediate in the bacteriorhodopsin photocycle

Bacteriorhodopsin is the simplest known photon-driven proton pump and as such provides a model for the study of a basic function in bioenergetics. Its seven transmembrane helices encompass a proton translocation pathway containing the chromophore, a retinal molecule covalently bound to lysine 216 through a protonated Schiff base, and a series of proton donors and acceptors. Photoisomerization of the all-trans retinal to the 13-cis configuration initiates the vectorial translocation of a proton from the Schiff base, the primary proton donor, to the extracellular side, followed by reprotonation of the Schiff base from the cytoplasm. Here we describe the high-resolution X-ray structure of an early intermediate in the photocycle of bacteriorhodopsin, which is formed directly after photoexcitation. A key water molecule is dislocated, allowing the primary proton acceptor, Asp 85, to move. Movement of the main-chain Lys 216 locally disrupts the hydrogen-bonding network of helix G, facilitating structural changes later in the photocycle.

Differential uptake of estramustine phosphate metabolites and its correlation with the levels of estramustine binding protein in prostate tumor tissue

Estracyt (EMP) has been used for the treatment of hormone refractory prostate cancer for many years. Recently, new data from combination studies have given rise to new interest in this old drug. Explanations for the synergy found in the clinic are many, but one major factor may be the previous indication that the drug accumulates in the prostate tumor. We have, therefore, examined the level of the four metabolites, estromustine (EoM), estramustine (EaM), estrone, and estradiol in the tumor and serum of 14 patients with T2 and T3 prostate cancer receiving a single i.v. dose of 600 mg of EMP, about 12 h before radical prostatectomy. Because it has been suggested that the uptake into the prostate tumor is due to binding to the estramustine binding protein (EMBP), we have in addition measured the level of EMBP in the prostate tumor tissue. The main serum and tissue metabolite in all patients was EoM followed by EaM, estrone, and estradiol. The levels for EoM ranged from 63.8-162.8 ng/ml in the serum and from 64.8-1209 ng/ml in the prostate tumor, resulting in a mean ratio for serum to tumor of 1:5. The levels for EaM ranged from 8.3-51.4 ng/ml in the serum and 73.9-563.4 ng/ml in the tumor, giving a mean ratio for serum to tumor of 1:13. The levels of EMBP were higher in T3 tumors than in T2 tumors, 54.1 and 40.7 ng/g tissue, respectively. A significant correlation was found between the levels of EaM (r = 0.60) and the levels of EMBP in the tumor. These data demonstrate that 12 h after a single i.v. dose of 600 mg of EMP the levels of the cytotoxic metabolites EoM and EaM are substantially higher in the tumor than in the serum of the same patient and that a correlation exists between the levels of EaM in the tumor and the levels of EMBP. Thus, this supports the hypothesis that the EMBP is responsible for the retention of EoM and EaM in the prostate tumor.

Distribution of estramustine in the BT4C rat glioma model

Estramustine (EaM), a carbamate ester of 17beta-estradiol and nor-nitrogen mustard, is a cytotoxic compound with antitumoral effect in malignant glioma in vitro and in vivo . However, knowledge of the pharmacokinetics of EaM in experimental glioma is limited. The objective of this study was therefore to investigate further the distribution of EaM in the BT4C rat glioma model. Assessment of EaM uptake and distribution was performed by quantitative whole-body autoradiography. In addition, the uptake of EaM and its metabolites estromustine (EoM), estradiol, and estrone were analyzed by gas chromatography. EaM was taken up from the circulation and was found to be the main product in glioma tissue. Whole-body autoradiography after [14C]-EaM administration revealed a strong 14C label simultaneously in tumor and normal brain tissue at 0.5 h after drug administration. In tumor tissue, sustained high levels of 14C label were detected at 12 h after drug administration. In contrast to the tumor, radioactivity in normal brain tissue rapidly leveled off, indicating a retention of radioactivity in the tumor. The tumor/brain radioactivity ratio reached a peak of 4.5 at 12 h after drug administration. High levels of 14C label were also found in pulmonary tissue. By gas chromatography, EoM was found to be the main metabolite in plasma. However, EaM reached higher levels in tumor tissue, with the mean tumor/plasma ratio being 11.7 as compared with 2.0 for EoM. Only low plasma levels of the estrogen metabolites were detected. In conclusion, EaM is taken up in the BT4C rat glioma tissue and is retained in the tumor as compared with normal brain tissue and plasma. EaM showed a greater selectivity for tumor tissue, exhibiting a high tumor/plasma ratio as compared with EoM. The distribution pattern after administration of EaM, as evaluated by both whole-body autoradiography and gas chromatography, supports the earlier suggestion that the uptake is related to a protein with EaM-binding characteristics.

Alcohol dehydrogenase genes: restriction fragment length polymorphisms for ADH4 (pi-ADH) and ADH5 (chi-ADH) and construction of haplotypes among different ADH classes

Of the five human alcohol dehydrogenase (ADH) genes located in the region q21-25 of chromosome 4, genetic markers have been reported previously only for class I enzymes, ADH1-3. Here, new restriction fragment length polymorphisms (RFLPs) are described for the genes of two other classes, ADH4 (pi) and ADH5 (chi or formaldehyde dehydrogenase, FDH). The frequencies and modes of inheritance of these RFLPs were determined with DNA both from unrelated individuals and from families. A polymorphic PstI site is assigned to the fourth intron of the ADH4 gene. Pairwise linkage disequilibrium calculations for these new RFLPs and already known RFLPs at the ADH2 and ADH3 loci establish strong linkage disequilibria between polymorphic MspI and BstXI sites in the ADH5 gene as well as between XbaI and MspI sites in the ADH3 gene. Furthermore, linkage disequilibria were detected between RFLPs of the ADH2 and ADH3 genes as well as between those of the ADH4 and ADH5 genes. The latter disequilibrium implies a hitherto unknown physical proximity of two genes belonging to different ADH classes. The RFLPs were used to construct chromosomal haplotypes that include three ADH classes. Of the 16 possible haplotypes for four RFLP markers used here, 10 were experimentally detected. The potential application of the ADH RFLPs and haplotypes in linkage or association studies of inherited diseases such as familial "alcoholism" is discussed.

Uptake and retention of estramustine and the presence of estramustine binding protein in malignant brain tumours in humans

Estraumustine phosphate (EMP), a cytotoxic drug used in the treatment of prostatic carcinoma, has been shown to exert cytotoxic effects on glioma cells in vitro. The drug uptake is assumed to depend on a specific estramustine binding protein (EMBP). One of the main difficulties in achieving cytotoxic effect in malignant brain tumours is believed to be due to the poor penetration of cytotoxic drugs into tumour tissue. In patients with malignant supratentorial brain tumours we have analysed the uptake of EMP metabolites in tumour tissue after oral administration and demonstrated EMBP in the same tissue specimens. Sixteen patients were given 280 mg EMP orally 14 h prior to surgery. Specimens from brain tumour tissue, cystic fluid, and serum were collected during surgery. Using gas chromatography the metabolites of EMP, estramustine (EaM) and estromustine (EoM), were quantified, EMBP was demonstrated by immunohistochemistry. The mean concentrations of EaM and EoM, expressed in ng g-1, were 60.3 and 38.4 in tumour tissue and 3.5 and 56.3 in serum, respectively. An accumulation of EaM in tumour tissue was found with a mean concentration gradient of 16.1 versus serum, while the gradient for EoM was 0.76. EMBP was demonstrated with a high degree of staining in all but one tumour. The high concentrations of EaM and EoM found in malignant brain tumour tissue correspond to potentially cytotoxic levels. The present results as well as the earlier in vitro demonstrated cytotoxic effects on glioma cells strengthen the possibility of a therapeutic effect of EMP in the treatment of malignant brain tumours.

Phospholipid and fatty acid composition in mitochondria from spinach (Spinacia oleracea) leaves and petioles. A comparative study

Essentially chlorophyll-free mitochondria from photosynthetic (leaf) and non-photosynthetic tissue (petiole) were isolated from spinach (Spinacia oleracea). Leaf mitochondria were found to contain more phosphatidylcholine than phosphatidylethanolamine compared with petiole mitochondria. Galactolipids were found in small and equal amounts (5 mol of galactolipids/100 mol of galactolipids and phospholipids) in both leaf and petiole mitochondria. Fatty acid composition showed a significant difference in the amounts of C18:2 and C18:3 acids. The C18:2/C18:3 ratio was more than twice as high in all of the phospholipids studied from petiole mitochondria compared with the ratio in leaf mitochondria. More than 50% (mol/100 mol) of the fatty acids in the major lipids (phosphatidylcholine, phosphatidylethanolamine and cardiolipin) in petiole mitochondria were C18:2. In the minor lipids (phosphatidylinositol and phosphatidylglycerol), C16:0 dominated in both leaf and petiole mitochondria.

The regulation of exogenous NAD(P)H oxidation in spinach (Spinacia oleracea) leaf mitochondria by pH and cations

Essentially chlorophyll-free mitochondria were isolated from green leaves of spinach (Spinacia oleracea L. cv. Viking II). Uncoupled oxidation of exogenous NADPH (1 mM) to oxygen had an optimum at pH 6.0, and activity was relatively low at pH 7.0, even in the presence of 1 mM-CaCl2. There was a proportional increase in the apparent Km for NADPH with decreasing H+ concentrations, suggesting that NADPH protonated on the 2'-phosphate group was the true substrate. Exogenous NADH was oxidized by oxygen with an optimum at pH 6.9. Under low-cation conditions, EGTA or EDTA (both 1 mM) had no effect on the Vmax. of NADH oxidation, although the removal of bivalent cations from the membrane surface by the chelators could be observed by use of 9-aminoacridine fluorescence. In contrast, under high-cation conditions, chelators lowered the Vmax. by about 50%, probably due to a better approach of the negatively charged chelators to the negative membrane surface than under low-cation conditions. In a low-cation medium, the Vmax. of NADH oxidation was increased by about 50% by the addition of cations. This was caused by a lowering of the size of the negative surface potential through charge screening. In contrast with other cations, La3+ inhibited NADH oxidation, possibly through binding to lipids essential for NADH oxidation. The apparent Km for NADH varied 6-fold in response to changes in the size of the surface potential, suggesting that the approach of the negatively charged NADH to the active site is hampered by the negative surface potential. The results demonstrate that the spinach leaf cell can regulate the mitochondrial NAD(P)H oxidation through several mechanisms: the pH; the cation concentration in general; and the concentration of Ca2+ in particular. The results also emphasize the importance of electrostatic considerations when investigating the kinetic behaviour of membrane-bound enzymes.