Home‐ and community‐level predictors of social connection in nursing home residents: A scoping review

Background and Aims

Methods

Results

Conclusion

Development and validation of a HILIC-MS/MS method for the quantitation of fructose in human urine in support of clinical programs

In a previous publication [1], a 20-minute UPLC®-MS/MS method, employing a surrogate analyte approach, was developed and validated to measure fructose and sorbitol, as mechanistic biomarkers, in human plasma to support first-in-human (FIH) studies. Different from plasma which maintains its homeostasis, urine has no such homeostasis mechanisms [2], therefore it is expected to be able to accommodate more changes. Here we describe the development and validation of a LC-MS/MS method for the quantiation of fructose in human urine to support clinical trials. A hydrophilic interaction chromatography (HILIC) method using an Asahipak NH2P-50 column (Shodex, 4.6 × 250 mm, 5 µm) was developed. Acetone precipitation was utilized to extract fructose from urine. For validation, stable isotope-labeled ¹³C₆-fructose was used as the surrogate analyte for fructose in the preparation of calibration curves. QCs were prepared using both the surrogate analyte (¹³C₆-fructose) and the authentic analyte (fructose). Difficulties were encountered for post-extraction stability experiments especially for authentic fructose QCs at low concentrations. Extensive troubleshooting revealed that fructose's chromatography improved as the column aged. As a result, the response factor of fructose increased over time for low concentration samples, leading to failed post-extraction stability experiments. A column cleaning procedure was implemented to ensure consistency in chromatography performance. The HILIC-MS/MS method was successfully validated and applied to analyze clinical samples with a 91% overall run passing rate.

The relationship between quality and staffing in long-term care: A systematic review of the literature 2008-2020

BACKGROUND

Higher staffing levels in long-term care have been associated with better outcomes for residents in several landmark studies. However previous systematic reviews found mixed results, calling into question the effectiveness of higher levels of staff. With persistent concerns about quality, rising resident acuity, and a growing demographic of seniors requiring more services, understanding the relationship between quality and long-term care staffing is a growing concern.

OBJECTIVES

This review considered the following question: What is the influence of nursing and personal care staffing levels (registered nurse, licensed practical nurse, and nursing assistant) and / or skill mix on long-term care residents, measured by quality of care indicators?

DESIGN

Preferred Reporting Items for Systematic Review and Meta-analysis Protocols guided the report of this systematic review.

DATA SOURCES

Published articles focused on quality and nursing and personal care staffing in long-term care in peer-reviewed databases (MEDLINE, CINAHL, and AGELINE) and several Cochrane databases to retrieve studies published between January 2008 and June 2020.

REVIEW METHODS

A systematic review was conducted. 11,096 studies were identified, of which 34 were included in this review. The Strengthening the Reporting of Observational Studies in Epidemiology checklist was used to evaluate study quality and risk of bias, and five quality measures were selected for in-depth analyses: pressure ulcers, hospitalizations, physical restraints, deficiencies and catherization.

RESULTS

This review confirms previous review findings that evidence on the relationships between quality and long-term care staffing level and skill mix, remain mixed. Higher staffing levels and skill mix generally supported better rather than worse outcomes. Significant and consistent findings were more evident when staffing levels were further analyzed by indicator and staffing category. For example, registered nurses were consistently associated with significantly fewer pressure ulcers, hospitalizations, and urinary tract infections. Few studies examined the impact of total nursing and personal care hours compared to the impact of specific categories or classes of nursing staff on outcomes.

CONCLUSIONS

Evidence on the relationship between quality and long-term care staffing remains mixed, however some categories of nursing staff may be more effective at improving the quality of certain indicators. Study quality has improved minimally over the last decade. Although research continues to standardize units of measurement, and longitudinal and instrumental variable analyses are increasingly being used, very few studies controlled for endogeneity, conducted adequate risk-adjustment, and used resident-level data. Additional strides must still be made to improve the rigor of long-term care staffing research.

Invasion windows for a global legume invader are revealed after joint examination of abiotic and biotic filters

Successful alien plant invasion is influenced by both climate change and plant-plant interactions. We estimate the single and interactive effects of competition and extreme weather events on the performance of the global legume invader Lupinus polyphyllus (Lindl.). In three experimental studies we assessed (i) the stress tolerance of seedling and adult L. polyphyllus plants against extreme weather events (drought, fluctuating precipitation, late frost), (ii) the competitive effects of L. polyphyllus on native grassland species and vice versa, and (iii) the interactive effects of extreme weather events and competition on the performance of L. polyphyllus. Drought reduced growth and led to early senescence of L. polyphyllus but did not reduce adult survival. Fluctuating precipitation events and late frost reduced the length of inflorescences. Under control conditions, interspecific competition reduced photosynthetic activity and growth of L. polyphyllus. When subjected to competition during drought, L. polyphyllus conserved water while simultaneously maintaining high assimilation rates, demonstrating increased water use efficiency. Meanwhile, native species had reduced performance under drought. In summary, the invader gained an advantage under drought conditions through a smaller reduction in performance relative to its native competitors but was competitively inferior under control conditions. This provides evidence for a possible invasion window for this species. While regions of high elevation or latitude with regular severe late frost events might remain inaccessible for L. polyphyllus, further spread across Europe seems probable as the predicted increase in drought events may favour this non-native legume over native species.

Southern Hemisphere forcing of South Asian monsoon precipitation over the past ~1 million years

The orbital-scale timing of South Asian monsoon (SAM) precipitation is poorly understood. Here we present new SST and seawater δ¹⁸O (δ¹⁸Osw) records from the Bay of Bengal, the core convective region of the South Asian monsoon, over the past 1 million years. Our records reveal that SAM precipitation peaked in the precession band ~9 kyrs after Northern Hemisphere summer insolation maxima, in phase with records of SAM winds in the Arabian Sea and eastern Indian Ocean. Precession-band variance, however, accounts for ~30% of the total variance of SAM precipitation while it was either absent or dominant in records of the East Asian monsoon (EAM). This and the observation that SAM precipitation was phase locked with obliquity minima and was sensitive to Southern Hemisphere warming provides clear evidence that SAM and EAM precipitation responded differently to orbital forcing and highlights the importance of internal processes forcing monsoon variability.

The orbital-scale timing of South Asian monsoon precipitation is poorly understood. Here the authors show that the long held view that precession drove changes in monsoon strength is wrong, and that obliquity and eccentricity played a stronger role.

Bioaccumulation and metabolisation of (14)C-pyrene by the Pacific oyster Crassostrea gigas exposed via seawater

The first objective of this study was to determine the bioaccumulation kinetics of pyrene in the soft tissues of Crassostrea gigas (mantle, muscle, gills, digestive gland, and the remaining soft tissues). As bivalves can biotransform hydrocarbons in more polar compounds (metabolites) that are more easily excreted, the second objective was to investigate the oyster capacity to metabolize pyrene into its metabolite, the 1-hydroxypyrene. To these ends, oysters were exposed 24 h to waterborne (14)C-pyrene then placed in depuration conditions for 15 d. Oysters efficiently bioaccumulated pyrene in their soft tissues and equilibrium was reached within the exposure time. The metabolite1-hydroxypyrene was also detected in oyster tissues but represented only 4-14% of the parent pyrene. At the end of the exposure period, the gills and the mantle showed the highest pyrene proportion of total soft tissue content, i.e. 47% and 26%, respectively. After 15 d of depuration, the mantle contained 32% and 30% of the remaining pyrene and 1-hydroxypyrene, respectively. As C. gigas did not display a high capacity for metabolizing pyrene, it can be considered as a good bioindicator species to survey and monitor pyrene contamination in the coastal marine environment.

Opposing modulatory effects of D1- and D2-like receptor activation on a spinal central pattern generator

The role of dopamine in regulating spinal cord function is receiving increasing attention, but its actions on spinal motor networks responsible for rhythmic behaviors remain poorly understood. Here, we have explored the modulatory influence of dopamine on locomotory central pattern generator (CPG) circuitry in the spinal cord of premetamorphic Xenopus laevis tadpoles. Bath application of exogenous dopamine to isolated brain stem-spinal cords exerted divergent dose-dependent effects on spontaneous episodic patterns of locomotory-related activity recorded extracellularly from spinal ventral roots. At low concentration (2 μM), dopamine reduced the occurrence of bursts and fictive swim episodes and increased episode cycle periods. In contrast, at high concentration (50 μM) dopamine reversed its actions on fictive swimming, now increasing both burst and swim episode occurrences while reducing episode periods. The low-dopamine effects were mimicked by the D2-like receptor agonists bromocriptine and quinpirole, whereas the D1-like receptor agonist SKF 38393 reproduced the effects of high dopamine. Furthermore, the motor response to the D1-like antagonist SCH 23390 resembled that to the D2 agonists, whereas the D2-like antagonist raclopride mimicked the effects of the D1 agonist. Together, these findings indicate that dopamine plays an important role in modulating spinal locomotor activity. Moreover, the transmitter's opposing influences on the same target CPG are likely to be accomplished by a specific, concentration-dependent recruitment of independent D2- and D1-like receptor signaling pathways that differentially mediate inhibitory and excitatory actions.

Identification of an Arabidopsis solute carrier critical for intracellular transport and inter-organ allocation of molybdate

Plants represent an important source of molybdenum in the human diet. Recently, MOT1 has been identified as a transport protein responsible for molybdate import in Arabidopsis thaliana L.; however, the function of the homologous protein MOT2 has not been resolved. Interestingly, MOT2-GFP analysis indicated a vacuolar location of this carrier protein. By site directed mutagenesis at the N-terminal end of MOT2, we identified a di-leucine motif that is essential for driving the protein into the vacuolar membrane. Molybdate quantification in isolated vacuoles showed that this organelle serves as an important molybdate store in Arabidopsis cells. When grown on soil, leaves from mot2 T-DNA mutants contained more molybdate, whereas mot2 seeds contained significantly less molybdate than corresponding wild-type (Wt) tissues. Remarkably, MOT2 mRNA accumulates in senescing leaves and mot2 leaves from plants that had finished their life cycle had 15-fold higher molybdate levels than Wt leaves. Reintroduction of the endogenous MOT2 gene led to a Wt molybdate phenotype. Thus, mot2 mutants exhibit impaired inter-organ molybdate allocation. As total concentrations of the molybdenum cofactor (Moco) and its precursor MPT correlates with leaf molybdate levels, we present novel evidence for an adjustment of Moco biosynthesis in response to cellular MoO₄²⁻ levels. We conclude that MOT2 is important for vacuolar molybdate export, an N-terminal di-leucine motif is critical for correct subcellular localisation of MOT2 and activity of this carrier is required for accumulation of molybdate in Arabidopsis seeds. MOT2 is a novel element in inter-organ translocation of an essential metal ion.

[On the spot treatment of active and inactive trachoma in lower Egypt]

BACKGROUND

In spite of WHO programmes with azithromycin therapy and prophylaxis of trachoma, active and inactive stages of trachoma have not yet lost their position as one of the leading causes of blindness worldwide. For underprivileged inhabitants a specially adapted catalogue of surgical procedures was selected and for the special purposes of on-the-spot surgery and follow-up with one, two or no further examinations or removal of suture material was adapted.

PATIENTS

For 45 patients with trichiasis, trachoma scarring of upper and lower lids with entropium and different kinds of corneal damage, eight different surgical procedures with, in part, modifications were adopted.

RESULTS

By modifications of known surgical procedures with postoperative correction of lid position, the more precise marking of trichiasis lashes, preparation to their roots for epilation or cauterisation and for minimal measurements in follow-up, essentials were found for adaptation to this purpose and the best procedures identified.

CONCLUSIONS

Eight different surgical procedures for different scarring stages of trachoma and trichiasis including entropium at the upper and lower lids with cornea pannus led, by a selected adaptation to the particular purposes and situations, to an overall success rate of > 90 %. Visual acuity improvements in 50 % of the patients were recognised. The otherwise present threat of blindness in the further course could be avoided.

[Binocular status of dyslexics--are there differences to a healthy comparison group?]

BACKGROUND

Despite numerous studies dealing with the question of a possible relation of visual problems and dyslexia, which is negated by most ophthalmologists, some opticians still favour the treatment of dyslexia by correction of the "Winkelfehlsichtigkeit" following MCH. Our aim was by also including the Pola test to check the usefulness of this treatment.

PATIENTS AND METHODS

In a 2-year prospective study we examined the 4th grade elementary school students in our city who had dyslexia as an assured diagnosis (n = 21). The results were compared to those of an age-matched group without pathological findings regarding their reading and spelling ability (n = 21). Examinations included visual acuity, eye position by cover test, Maddox cylinder and Pola test for near distance, binocular vision (Bagolini and Worth test, Lang test I and II, Titmus test, amplitude of fusion), amplitude of accommodation, refraction in cycloplegia and organic status.

RESULTS

A significant difference was found between the two groups regarding the amplitude of divergence in near (p = 0.009) and far distance (p = 0.019) which were both smaller for the dyslexia group, as well as the binocular near visual acuity (p = 0.04). Using the SAS procedure STEPDISC we discriminated the normal and dyslexia group by amplitude of divergence, near visual acuity and alternating near prism cover test with a sensitivity of 81 % and a specifity of 75 %. The results of the Pola test did not show any significant difference between the groups.

CONCLUSIONS

No differences were found between the groups regarding the eye position. Therefore a treatment of dyslexia using prisms does not appear reasonable. However because of the group sizes the significance of the results is limited.

The retinal pigment epithelium in clinical echography

The resolution of the Triscan (Biophysic Medical) and the Cooper-Alcon 2000 equipments proved sufficient for depicting three separate curvilinear echostructures from the back of the eye. The anatomical counterparts are the inner limiting membrane of the retina, the pigment epithelium, and the inner surface of the sclera. Imaging will be impeded due to sound dispersion if the sound beam is directed through the lens, or via the cornea and the pars plicata of the ciliary body, respectively. The potential of the method is discussed.

Embedded ferroelectric nanostructure arrays

Ferroelectrics hold promise for high-density non-volatile data storage device use. Their eventual performance will strongly depend on the available displacement current, which primarily scales with the area but might to some extent be enhanced by substrate-induced homogeneous strain while the interface at the same time controls the coercive field. As the lateral dimensions persistently decrease, the only way to keep track of the real figures of merit with realistic electrodes is to use a macroscopic configuration instead of scanning probe approaches with undefined interfaces. We report on a novel approach to integrating arbitrarily patterned, highly registered ferroelectric nanoislands fabricated by a template controlled chemical solution deposition approach into a matrix of a low-k dielectric spin-on glass. These structures with a narrow lateral size distribution below 100 nm are subsequently polished in a chemical-mechanical polishing step to expose their very tops, whose piezoelectrically active area depends on the polishing time. At this stage our findings indicate a full piezoelectric functionality of the locally exposed nanoislands. The structures are ready for macroscopic top electrodes to average the displacement current over hundreds of almost identical structures, to provide a nanoscale scaling behaviour of the individual ferroelectric capacitors.

Retention of phenylalanine ammonia-lyase activity in wheat seedlings during storage and in vitro digestion

The retention of phenylalanine ammonia-lyase (PAL) activity in Red Spring wheat seedlings during storage and in vitro protein digestion was evaluated toward assessing the efficacy of plant PAL as a dietary supplement for patients suffering from the metabolic disease, phenylketonuria. Retention of PAL activity in freeze-dried wheat seedling tissues following three months of storage at -20 degrees C ranged from 62% in the leaf to 89% in root/residual seed tissues. After a 3-h two-stage ("gastric-intestinal") in vitro digestion, 36% and 42% recovery of PAL activity was associated with chopped fresh leaf and root/residual seed tissues respectively; however, no activity was recovered from freeze-dried tissues. High performance liquid chromatographic analysis of the residual phenylalanine (Phe) after in vitro digestion confirmed that the fresh tissues effected a significantly higher conversion of exogenous Phe than freeze-dried tissues. These results demonstrate that the plant cell walls provide protection of PAL during in vitro digestion. In cases where exogenous Phe (100 mg; 24 mM) was supplied to the tissues, the product of the reaction, trans-cinnamic acid, may have exerted a significant inhibitory effect on PAL activity.

Expression and distribution of all dopamine receptor subtypes (D(1)-D(5)) in the mouse lumbar spinal cord: a real-time polymerase chain reaction and non-autoradiographic in situ hybridization study

Dopamine is a catecholaminergic neuromodulatory transmitter that acts through five molecularly-distinct G protein-coupled receptor subtypes (D(1)-D(5)). In the mammalian spinal cord, dopaminergic axon collaterals arise predominantly from the A11 region of the dorsoposterior hypothalamus and project diffusely throughout the spinal neuraxis. Dopaminergic modulatory actions are implicated in sensory, motor and autonomic functions in the spinal cord but the expression properties of the different dopamine receptors in the spinal cord remain incomplete. Here we determined the presence and the regional distribution of all dopamine receptor subtypes in mouse spinal cord cells by means of quantitative real time polymerase chain reaction (PCR) and digoxigenin-label in situ hybridization. Real-time PCR demonstrated that all dopamine receptors are expressed in the spinal cord with strongly dominant D(2) receptor expression, including in motoneurons and in the sensory encoding superficial dorsal horn (SDH). Laser capture microdissection (LCM) corroborated the predominance of D(2) receptor expression in SDH and motoneurons. In situ hybridization of lumbar cord revealed that expression for all dopamine receptors was largely in the gray matter, including motoneurons, and distributed diffusely in labeled cell subpopulations in most or all laminae. The highest incidence of cellular labeling was observed for D(2) and D(5) receptors, while the incidence of D(1) and D(3) receptor expression was least. We conclude that the expression and extensive postsynaptic distribution of all known dopamine receptors in spinal cord correspond well with the broad descending dopaminergic projection territory supporting a widespread dopaminergic control over spinal neuronal systems. The dominant expression of D(2) receptors suggests a leading role for these receptors in dopaminergic actions on postsynaptic spinal neurons.

Toxic metal accumulation, responses to exposure and mechanisms of tolerance in plants

Over the past 200 years emissions of toxic heavy metals have risen tremendously and significantly exceed those from natural sources for practically all metals. Uptake and accumulation by crop plants represents the main entry pathway for potentially health-threatening toxic metals into human and animal food. Of major concern are the metalloids arsenic (As) and selenium (Se), and the metals cadmium (Cd), mercury (Hg), and lead (Pb). This review discusses the molecular mechanisms of toxic metal accumulation in plants and algae, the responses to metal exposure, as well as our understanding of metal tolerance and its evolution. The main emphasis will be on cadmium, which is by far the most widely studied of the non-essential toxic metals/metalloids. Entry via Zn2+, Fe2+, and Ca2+ transporters is the molecular basis of Cd2+ uptake into plant cells. Much less is known about the partitioning of non-essential metals and about the genes underlying the enormous diversity among plants with respect to Cd accumulation in different tissues. Numerous studies have described symptoms and responses of plants upon toxic metal exposure. Mysterious are primary targets of toxicity, the degree of specificity of responses, the sensing and the signaling events that lead to transcriptional activation. All plants apparently possess a basal tolerance of toxic non-essential metals. For Cd and As, this is largely dependent on the phytochelatin pathway. Not understood is the molecular biology of Cd hypertolerance in certain plant species such as the metallophytes Arabidopsis halleri or Thlaspi caerulescens.

[Optical lamellar-penetrating keratoplasty with stem cell transplantation in high-risk cases]

BACKGROUND

Stem cells of the corneal epithelium are located mainly at the sclerocorneal limbus, and are essential for the maintenance of a healthy corneal surface. Limbal stem cell deficiency leads--depending on intensity and extension--to several corneal alterations. The appearance of limbal stem cell deficiency is chiefly concentrated on pemphigoids, Herpes relapses and alkali burns and represents the main part of high-risk keratoplasty. The different types of limbal stem cell deficiency (partial or total) are usually treated with several surgical techniques. Total limbal deficiency can be treated with limbal transplantation, either of the healthy eye (limbal autograft), or using material of another donor (limbal allograft).

METHODS AND RESULTS

Lamellar-penetrating keratoplasty (L-P-KP) has been carried out in five patients. Unlike recent surgical techniques containing ring-shaped or circular transplantations, a stripe-like lamellar preparation was performed. L-P-KP involves a peripheral lamellar and a central penetrating keratoplasty combined with limbal stem cell transplantation. In four of six cases, the transplant has been successfully kept clear without the occurrence of corneal decompensation or ulceration. No major changes could be seen between pre- and postoperative visual acuity. The mean observation period was 24 months.

DISCUSSION

L-P-KP offers a new surgical opportunity in the treatment of high-risk cases of limbal deficiency.

[Minimally invasive endoscopic surgery of the lacrimal drainage system--two case reports]

BACKGROUND

Dacryoendoscopy is a standard procedure to directly evaluate the lacrimal system. The existence and localisation of dacryostenosis and mucosal changes as well as rare diseases in the drainage system, such as intracanalicular foreign bodies or dacryoliths, can be reliably detected and treated by minimally invasive endoscopic surgery.

HISTORY AND SIGNS

A patient treated by canaliclulodacryozystorhinostomy with silicone tube intubation 5 years ago had a long symptom-free period but now shows tearing (epiphora) and occasional mucous secretion. During endoscopy residues of a silicone tube coated with a biofilm could be removed over the lacrimal canaliculus and then tested for microbiological contamination. A second patient with tearing, light mucous secretion and positive nasolacrimal duct irrigation was initially diagnosed with a tear-film disorder. Dacryoendoscopy showed a dacryolith in the saccus lacrimalis. This was consequently fragmented using a microdrill system and fully removed through the nasolacrimal duct as well as the lacrimal canaliculus.

CONCLUSIONS

Endoscopy of the proximal and distal lacrimal system allows the assessment of intracanalicular structures and a reliable detection or exclusion of disorders in the draining system. This method is of great diagnostic importance as symptoms are frequently non-specific and the causes are multiple. Through endoscopy in combination with the use of a microdrill system the lacrimal system can be reopened and adequately reconstructed.

Reversal of the circadian expression of tyrosine-hydroxylase but not nitric oxide synthase levels in the spinal cord of dopamine D3 receptor knockout mice

Circadian rhythms have been described for numerous transmitter synthesizing enzymes in the brain but rarely in spinal cord. We measured spinal tyrosine-hydroxylase (TH) and nitric oxide synthase (NOS) levels in the thoracic intermediolateral nucleus, the location of sympathetic preganglionic neurons, in male wild type (WT) and dopamine D(3) receptor knockout mice (D(3)KO). TH and NOS levels both displayed circadian patterns in WT and D(3)KO animals with overall reduced TH and increased NOS expression in the D(3)KO mice. The circadian pattern of NOS expression was similar in WT and D(3)KO mice. In contrast, TH expression was inverted in D(3)KO mice, with TH levels consistently lower than in WT throughout the day, but strongly increased temporarily 1 h prior to daylight. TH is the rate-limiting enzyme for the production of dopamine. Spinal dopamine dysfunction is implicated in a sleep disorder called restless legs syndrome (RLS). RLS follows a circadian rhythm and is relieved clinically by dopamine D(3) receptor agonists. Our observations of an altered circadian pattern in spinal dopamine synthesis in D(3)KO animals may provide insight into putative dopaminergic mechanisms contributing to RLS.

Adjuvante Wirkung von EMLA®-Creme bei der Oberlidblepharoplastik

BACKGROUND

The injection of local anesthesia before upper lid blepharoplasty is perceived as unpleasant and painful by some patients.

METHODS

In an intraindividual randomized prospective study, 14 patients undergoing upper lid blepharoplasty on both sides were examined. Before the operation the EMLA creme was put on one side. The pain sensibility was checked before and after using EMLA creme and during the infiltration of anesthesia and the operation.

RESULTS

The sensitivity before putting on EMLA creme was equal in all patients on both sides. After application there was a distinct difference between the sides. During the infiltration of anesthesia 12 patients reported low and 2 patients medium pain on the treated side, while on the non-treated side 5 patients reported low, 4 patients medium, and 5 patients severe pain.

CONCLUSIONS

Applying EMLA creme before an operation reduces the pain sensitivity during infiltration of anesthesia and during the operation.

Registered Deposition of Nanoscale Ferroelectric Grains by Template-Controlled Growth

Regular patterns of ferroelectric PbTiO₃ nanostructures with lateral dimensions down to 30-60 nm have been grown onto platinized Si substrates by chemical solution deposition. The high registration of the grains is achieved by "top-down"-generated templates of TiO₂ dots as seeds for their deposition. Ferroelectricity was verified by piezoresponse force microscopy.

[Is the implantation of titanium stems in hip prostheses really obsolete?]

AIM

Due to several bad results of studies, titanium is no longer used as an implant material in cemented total hip arthroplasty. This study attempts figure out by means of a meta-analysis if the material titanium itself was responsible for the bad results of some studies or if specific implant characteristics contributed to implant failure, independent of titanium.

METHOD

Studies between 1960 and July 2002 were analysed concerning failure rates of cemented titanium total hip arthroplasties regarding their specific implant characteristics.

RESULTS

Specific implant characteristics such as roughness of the surface and geometrical features led to significantly different failure rates. Stems of titanium with a dull surface and a wide proximal geometry could achieve such good results as those of the cobalt-chromium stems published in the study results of Malchau.

CONCLUSION

Titanium is justified as a cementable material in total hip arthroplasty. By respecting specific implant characteristics, very good failure rates can be achieved. The high failure rates, published in several studies, are based upon implant characteristics which are not suitable for cementing techniques and not upon the implant material titanium itself.

[The influence of transport on organ cultured corneas. An experimental study of porcine corneal endothelium]

BACKGROUND

To investigate the influence of transport on the quality of corneas in organ culture, based on the vitality of the corneal endothelium.

METHODS

Transport was simulated for 222 porcine corneal disks. These were placed in standard transportation containers filled with organ culture medium II, kept in an incubator and then shaken on a laboratory shaker.

RESULTS

Agitated corneas at all acceleration rates always showed less endothelial cell damage than corneas kept motionless. The best condition was found after maximum accelerations of 0.10 g and 0.72 g. Damage consisted predominantly of disseminated cell loss and circular cell damage. A storage temperature of 37 degrees C caused most harm to the endothelium.

CONCLUSION

The reduction in endothelial damage found in corneas after agitation can be attributed to a better distribution of nutrients in the transportation container. Assuming transferability, a better quality of human grafts can be achieved by inducing slight motions of corneas in organ culture.

The cartilage-sparing versus the cartilage-cutting technique: a retrospective quality control comparison of the Francesconi and Converse otoplasties

From a total of 281 patients with protruding ears who underwent a bilateral otoplasty between 1990 and 2001, a group of 28 (10%) was selected for a retrospective quality control study. The goal was to compare two methods of otoplasty, the Francesconi, a cartilage-sparing technique, and the Converse, a cartilage-cutting technique, in terms of objectively measurable and subjectively discernable differences in results. Objective parameters included measurement of the three cephaloauricular distances and the conchoscapal angle. An independent plastic surgeon performed the evaluation by means of a systematic evaluation system for rating cosmetic surgical procedures and a 5-point visual analog scale for rating satisfaction. The patients' subjective rate of satisfaction also was investigated using the 5-point scale. The mean medial and inferior cephaloauricular distances were significantly smaller in the Francesconi group. The concoscaphal angle was 90 degrees, or less in all the patients of the Francesconi group, but more than 90 degrees in eight patients (57%) of the Converse group (p = 0.041). Accordingly, the independent surgeon found adequate correction of protrusion in 86% of the Francesconi group and 50% of the Converse group (p = 0.050). His satisfaction rate was significantly in favor of the Francesconi technique (p = 0.006). Not unexpectedly, the patients' satisfaction rate was comparably high in both groups, and there was no statistical difference between them. In conclusion, the quality control led to a clear preference of the Francesconi over the Converse otoplasty. In addition, the assessment of the postoperative results with the systematic evaluation system offered an excellent information base by which to judge the results of otoplasty. Consequent use of this evaluation system will lead to progress in the surgical procedure.

Developing tools for phytoremediation: towards a molecular understanding of plant metal tolerance and accumulation

Certain plant species and genotypes are able to accumulate large quantities of heavy metals in their shoots. Based on this trait the concept of phytoremediation was developed, i.e. the use of metal hyperaccumulating plants for the cleansing of contaminated soils and water. In order to more efficiently use this capacity, an engineering of plants might be needed. However, very little is known about the underlying molecular mechanisms. Our work is focussing on the identification and characterization of plant genes involved in plant metal uptake, tolerance and accumulation. Phytochelatins are small glutathione-derived metal-binding peptides which are part of the plant metal detoxification system. Genes encoding phytochelatin synthases have been cloned and are now being studied with regard to their regulation, biochemistry and biotechnological potential. Another project aimes at the dissection of metal responses in the metallophyte Arabidopsis halleri. This plant, a close relative to the model plant Arabidopsis thaliana, is Cd hypertolerant and Zn hyperaccumulating. It grows, for instance, on medieval mining sites in the Harz mountains in Germany and in many other metal-contaminated sites in Central Europe. We have isolated metal-regulated genes from A. halleri and molecularly analyzed interesting candidate genes with regard to their function and involvement in metal accumulation and tolerance.

[20-MHz ultrasound of pre-saccular lacrimal ducts]

BACKGROUND

In clinical practice, ultrasound examination of the lacrimal drainage system is not able to represent the lacrimal canaliculi with a high quality but the high-resolution ultrasound with 20 MHz transducer is a better possibility to get images of the lacrimal canaliculi.

PATIENTS AND METHODS

A total of 20 patients suffering from diseases of the lacrimal drainage system were examined ultrasonographically. Detection and localisation of the lacrimal canaliculi was made by a 20 MHz sector scanner in combination with the ultrasound diagnostic system I. After patient positioning, the high-resolution ultrasound investigation was done via immersion connection (methylcellulose). Instillation of viscoelastic substances (e.g. Healon) was necessary to detect the lacrimal canaliculi.

RESULTS

In all investigated patients, the high-resolution ultrasound (transducer frequency of 20 MHz) allowed reproducible images of the lacrimal drainage system. Without viscoelastic substances, a good echographic visualisation of canaliculi structures was obtained from patients with chronic canaliculitis or dislocated punctum plugs. In chronic canaliculitis the ultrasonic images showed an ectatic canaliculus (diverticulum) and high-reflective structures (concrements).

CONCLUSION

The high-resolution ultrasound (transducer frequency of 20 MHz) seems to be well suited for investigations of the lacrimal drainage system. In comparison with ultrasound biomicroscopy the resolution is lower but the depth of penetration is higher. The use of 20 MHz ultrasonic examination can be helpful in the clinical diagnostic of chronic canaliculitis.

A modulatory role for oxygen in shaping rhythmic motor output patterns of neuronal networks

It is becoming increasingly evident that O(2)-uptake in animal tissue is not only devoted to energy production. Here we review recent findings on a novel role of tissue oxygenation, notably in controlling the operation of neuronal networks in the central nervous system. Electrophysiological recordings in vivo and in vitro from rhythmically-active motor pattern generating networks in the lobster stomatogastric ganglion (STG) have revealed that oxygen is able to act in a manner equivalent to a classical neuromodulator. Local P(O(2)) variations within the low, but physiological range of 1-6 kPa are able to shape ongoing activity of these networks and therefore the motor behaviours in which they are involved. Oxygen's contribution to two of these, feeding and moulting, have been investigated. Importantly, the P(O(2)) effects are not related to hypoxic depression but are highly specific in terms of the network, neuron and even the synapse targeted. Our results are discussed in terms of functional significance and new research directions for mammalian physiology.

Arabidopsis thaliana expresses a second functional phytochelatin synthase

Phytochelatins represent a major detoxifying pathway for heavy metals in plants and many other organisms. The Arabidopsis thaliana CAD1 (=AtPCS1) gene encodes a phytochelatin synthase and cad1 mutants are phytochelatin deficient and cadmium hypersensitive. The Arabidopsis genome contains a highly homologous gene, AtPCS2, of which expression and function were studied in order to understand the apparent non-redundancy of the two genes. Low constitutive AtPCS2 expression is detected in all plant organs analyzed. The AtPCS2 gene encodes a functional phytochelatin synthase as shown by expression in Saccharomyces cerevisiae and the complementation of a Schizosaccharomyces pombe phytochelatin synthase knockout strain.

Caenorhabditis elegans expresses a functional phytochelatin synthase

The formation of phytochelatins, small metal-binding glutathione-derived peptides, is one of the well-studied responses of plants to toxic metal exposure. Phytochelatins have also been detected in some fungi and some marine diatoms. Genes encoding phytochelatin synthases (PCS) have recently been cloned from Arabidopsis, wheat and Schizosaccharomyces pombe. Surprisingly, database searches revealed the presence of a homologous gene in the Caenorhabditis elegans genome, DDBJ/EMBL/GenBank accession no. 266513. Here we show that C. elegans indeed expresses a gene coding for a functional phytochelatin synthase. CePCS complements the Cd2+ sensitivity of a Schizosaccharomyces pombe PCS knock-out strain and confers phytochelatin synthase activity to these cells. Thus, phytochelatins may play a role for metal homeostasis also in certain animals.

Molecular mechanisms of plant metal tolerance and homeostasis

Transition metals such as copper are essential for many physiological processes yet can be toxic at elevated levels. Other metals (e.g. lead) are nonessential and potentially highly toxic. Plants--like all other organisms--possess homeostatic mechanisms to maintain the correct concentrations of essential metal ions in different cellular compartments and to minimize the damage from exposure to nonessential metal ions. A regulated network of metal transport, chelation, trafficking and sequestration activities functions to provide the uptake, distribution and detoxification of metal ions. Some of the components of this network have now been identified: a number of uptake transporters have been cloned as well as candidate transporters for the vacuolar sequestration of metals. Chelators and chaperones are known, and evidence for intracellular metal trafficking is emerging. This recent progress in the molecular understanding of plant metal homeostasis and tolerance is reviewed.

Clinical diagnosis of chronic canaliculitis by 20-MHz ultrasound

The practical value of high-resolution ultrasound (transducer frequency of 20 MHz) in the study of the lacrimal canaliculi has been proven. It can also be used in the clinical diagnosis of chronic canaliculitis. If the classic symptoms are absent, the clinical diagnosis is often inaccurate, and treatment is insufficient. Representative images of normal cases and of chronic canaliculitis illustrate the potential of high-resolution ultrasound. In our patient, 20-MHz scanner images revealed pathological findings which were invisible during slitlamp examination. Ultrasonic images of chronic canaliculitis showed ectasia of the canaliculus and sulfur grains. High-resolution ultrasonic examination of the lacrimal drainage system demonstrated that the 20-MHz scanner used was able to show concrements (sulfur grains), measuring 1-2 mm in diameter. Such more reflective structures (like sulfur grains) are a pathognomonic sign of chronic canaliculitis. Our report confirms the efficiency of 20-MHz sonography in the diagnosis of canaliculitis without any side effects.

Identified serotonergic neurons in the Tritonia swim CPG activate both ionotropic and metabotropic receptors

Although G-protein-coupled (metabotropic) receptors are known to modulate the production of motor patterns, evidence from the escape swim central pattern generator (CPG) of the nudibranch mollusk, Tritonia diomedea, suggests that they might also participate in the generation of the motor pattern itself. The dorsal swim interneurons (DSIs), identified serotonergic neurons intrinsic to the Tritonia swim CPG, evoke dual component synaptic potentials onto other CPG neurons and premotor interneurons. Both the fast and slow components were previously shown to be due to serotonin (5-HT) acting at distinct postsynaptic receptors. We find that blocking or facilitating metabotropic receptors in a postsynaptic premotor interneuron differentially affects the fast and slow synaptic responses to DSI stimulation. Blocking G-protein activation by iontophoretically injecting the GDP-analogue guanosine 5'-O-(2-thiodiphosphate) (GDP-beta-S) did not significantly affect the DSI-evoked fast excitatory postsynaptic potential (EPSP) but decreased the amplitude of the slow component more than 50%. Injection of the GTP analogues guanosine 5'-O-(3-thiotriphosphate) (GTP-gamma-S) and 5'-guanylyl-imidodiphosphate, to prolong G-protein activation, had mixed effects on the fast component but increased the amplitude and duration of the slow component of the DSI-evoked response and, with repeated DSI stimulation, led to a persistent depolarization. These results indicate that the fast component of the biphasic synaptic potential evoked by a serotonergic CPG neuron onto premotor interneurons is mediated by ionotropic receptors (5-HT-gated ion channels), whereas the slow component is mediated by G-protein-coupled receptors. A similar synaptic activation of metabotropic receptors might also be found within the CPG itself, where it could exert a direct influence onto motor pattern generation.

Biochemical networks in nervous systems: expanding neuronal information capacity beyond voltage signals

In addition to synaptically mediated signals that are based on changes in membrane potential, neurons also generate and receive many types of signals that involve biochemical pathways, some of which are independent of voltage. Although networks of biochemical pathways have often been thought of as being only neuromodulatory, recent computational and experimental studies have highlighted how these pathways can also integrate and transfer information themselves. Interactions between biochemical pathways involving positive and negative feedback loops allow biochemical signals to exhibit emergent properties, most notably bistability and oscillations. New and evolving techniques, including real-time imaging of second messengers, hold the promise of illuminating information processing that cannot be detected using microelectrodes, and revealing how 'biochemical integration' might contribute to the computational abilities of the nervous system.

Expression of the wax-specific condensing enzyme CUT1 in Arabidopsis

The Arabidopsis thaliana gene CUT1 encodes a very-long-chain fatty acid-condensing enzyme required for the production of epicuticular wax in bolting stems. We have examined the expression pattern of CUT1 in Arabidopsis at different developmental stages and under different environmental conditions. RNA blot analysis showed that CUT1 was highly expressed in shoots, but not in roots. CUT1 expression was detectable throughout development. Light was required for CUT1 expression, and expression was increased by salt and drought treatments. The promoter region of the CUT1 gene was cloned, and 1.2 kb of the sequence 5' to the translation start codon was used to direct beta-glucuronidase (GUS) expression in transgenic plants. Histochemical and fluorometric (quantitative) GUS assays confirmed that the CUT1 promoter directed epidermal-specific expression and was highly active in Arabidopsis and in tobacco. A construct using the CUT1 promoter to drive CUT1 expression (CUT1p-CUT1) was used to transform Arabidopsis. Transgenic plants which had somewhat increased (overexpression) or greatly reduced (co-suppression) wax loads were recovered. Thus, the CUT1 promoter should be useful for genetic engineering applications that require epidermis-specific expression of genes.