[The most serious incident-Experiences of aggression and violence in ophthalmology]

BACKGROUND

Experiences of aggression/violence influence job satisfaction and can have a long-term psychological and physical impact on employees. In the fall of 2018, the Professional Association of Ophthalmologists (BVA) and the German Ophthalmological Society (DOG) conducted a survey on experiences of aggression and violence. The first results were published in 2020. In the survey it was also possible to describe the most serious incident to date using free text fields, among others.

METHOD

All 9411 members of the DOG and BVA were given the opportunity to complete a questionnaire online in 2018 regarding aggression and violence in ophthalmology.

RESULTS

Overall, 253 of 1508 (16.8%) ophthalmologists participating in the survey reported their most serious incident, 46.8% of which were classified as moderate and 34.3% were related to verbal violence such as insults and threats. The most serious incident was experienced by 171 (67.6%) physicians in a practice setting, 71% were specialists at the time of the incident and 74.3% of the incidents occurred during regular working hours. The main causes were intercultural conflicts, long waiting times, problems with the allocation of appointments, excessive expectations, differences in treatment and basic aggressiveness. The offenders were male in 86.3% of cases, 15.8% of the incidents were reported to the police and 21 (8.3%) physicians issued a practice reprimand or house ban.

DISCUSSION

The description of the most serious incidents illustrates situations that are sometimes hard to imagine and also which incidents were considered serious. There are large subjective variations in the assessment of the incidents. Protective measures in practices and clinics are essential.

Advances and challenges in cryo ptychography at the Advanced Photon Source

Ptychography has emerged as a nondestructive tool to quantitatively study extended samples at a high spatial resolution. In this manuscript, we report on recent developments from our team. We have combined cryo ptychography and fluorescence microscopy to provide simultaneous views of ultrastructure and elemental composition, we have developed multi-GPU parallel computation to speed up ptychographic reconstructions, and we have implemented fly-scan ptychography to allow for faster data acquisition. We conclude with a discussion of future challenges in high-resolution 3D ptychography.

Cisplatin resistance in germ cell tumours: models and mechanisms

Recent years have led to a better understanding of the mechanisms underlying cisplatin response and resistance in germ cell tumours (GCT), and several promising targets have been identified. Two main mechanisms of the responsiveness to DNA damaging agents have been postulated. Firstly, GCT readily activate a DNA damage response, but show deficits in several damage repair pathways. In particular, they have been found to have defects in interstrand crosslink repair and in homologous recombination (HR). Secondly, GCT, especially embryonal carcinoma (EC) cells, show a hypersensitive apoptotic response to DNA damage, which activates p53, and leads to up-regulation of the pro-apoptotic factors Noxa, Puma and Fas in non-resistant EC. These cells fail to activate p21 which induces a G1/S arrest, but accumulate in G2/M phase. In the absence of functional p53, family members like p73 and GTAp63 might be important in initiating this response. Mechanisms involved in cisplatin resistance are as follows: down-regulation of Oct4 (e.g. as a result of hypoxia, treatment with retinoic acid or exposure to cisplatin) and failure to induce Puma and Noxa; changes in the expression levels of micro-RNAs such as miR-17/-106b, miR-302a, or miR-371 to -373; elevated levels of MDM2 and cytoplasmic translocation of p21 by phosphorylation; and activation of the PDGFRβ/PI3K/pAKT pathway. Several approaches to overcome resistance have been successfully examined in vitro and in vivo, including PARP inhibitors, especially in cells showing deficient HR-repair; stabilization of p53 using nutlin-3; inhibition of several components of the PI3K/pAKT pathway using small molecules; and DNA demethylation by 5-azacytidine or 5-aza-deoxy-cytidine, among others. Many of these substances deserve further exploration, alone or in combination with DNA damaging agents, and the most promising approaches should be taken forward to clinical testing. Targeted therapy based on mechanistic insights holds the promise to turn cisplatin-resistant GCT into a curable disease.

[Interface between university medicine and patient care]

The working profile of university hospitals includes medical education, research and implementation of medical innovations as well as large volume patient care. University hospitals offer inpatient, day care and outpatient care which are of essential value for many patients. Besides their primary role in treating rare and orphan diseases and complex cases, they increasingly support general patient care. There are different kinds of outpatient access and treatment options available. The funding of university hospitals and clinics is based on general university funding, income from third party funds for research, income from patient care and funding from the federal states for investments. In recent years these institutions have suffered more and more from economic deficits, a lack of investment and inadequate funding whereby high performance medicine cannot be sufficiently supported. Professors are developing into scientific managers and are frequently assessed by economic outcome and competitiveness. At the same time they are embedded in the structures of the university and are not in the position to make decisions on their own, in contrast to doctors in private practices. Therefore, processes, necessary investments and restructuring are significantly delayed. There is a need to develop strategies for long-term funding and providing university hospitals and clinics with the means to deliver the necessary services.

The phosphorous necrosis of the jaws and what can we learn from the past: a comparison of "phossy" and "bisphossy" jaw

INTRODUCTION

The osteopathology of the jaws associated with bone resorption inhibitors is a current topic that engages a variety of clinical specialists. This has increased after the approval of denosumab for treatment of osteoporosis and skeletal-related events in patients with solid malignancy. Early after the first publications, there is a possible connection between phosphorous necrosis of the jaws, a dreadful industrial disease mentioned, and bisphosphonate-induced pathology. The nineteenth century was the prime time for phosphorus necrosis of match factory workers.

RESULTS

This occurrence provides an interesting insight into the medical and surgical profession in the nineteenth century. There are striking parallels and repetition of current and old ideas in the approach to this "new disease." There are similar examples in case descriptions when compared with today's patients of bisphosphonate-related osteonecrosis of the jaws (BRONJ).

DISCUSSION

Phosphorus necrosis was first described in Austria. Soon after this, surgeons in German-speaking countries including well-known clinicians Wegner (1872) and von Schulthess-Rechberg (1879) pioneered the analysis, preventative measures, and treatment of this disease. The tendency at this time was to approach BRONJ as a "special kind of osteomyelitis" in pretreated and metabolically different bone. Not only the treatment strategy to wait until sequestrum formation with subsequent removal and preventative measures but also the idea of focusing on the periosteum as the triggering anatomical structure may have been adopted from specialists in the nineteenth century. Therefore, phosphorous necrosis of the jaw is an excellent example of "learning from the past."

The Bionanoprobe: hard X-ray fluorescence nanoprobe with cryogenic capabilities

Hard X-ray fluorescence microscopy is one of the most sensitive techniques for performing trace elemental analysis of biological samples such as whole cells and tissues. Conventional sample preparation methods usually involve dehydration, which removes cellular water and may consequently cause structural collapse, or invasive processes such as embedding. Radiation-induced artifacts may also become an issue, particularly as the spatial resolution increases beyond the sub-micrometer scale. To allow imaging under hydrated conditions, close to the `natural state', as well as to reduce structural radiation damage, the Bionanoprobe (BNP) has been developed, a hard X-ray fluorescence nanoprobe with cryogenic sample environment and cryo transfer capabilities, dedicated to studying trace elements in frozen-hydrated biological systems. The BNP is installed at an undulator beamline at sector 21 of the Advanced Photon Source. It provides a spatial resolution of 30 nm for two-dimensional fluorescence imaging. In this first demonstration the instrument design and motion control principles are described, the instrument performance is quantified, and the first results obtained with the BNP on frozen-hydrated whole cells are reported.

Osteopathology associated with bone resorption inhibitors - which role does Actinomyces play? A presentation of 51 cases with systematic review of the literature

BACKGROUND

Bone resorption inhibitor-related osteopathology of the jaw (BRIOJ) is a severe complication in patients treated with bisphosphonates or denosumab. However, the precise pathogenesis of BRIOJ is not yet fully understood. Recent studies discovered the presence of Actinomyces colonies in biopsy material from BRIOJ patients. The aim of this study was to analyze current knowledge concerning the impact of Actinomyces on the pathogenesis of this condition and to present data from our own patients.

METHODS

Data from 51 patients with histopathological diagnoses of BRIOJ were retrospectively analyzed. In addition, a systematic literature search for studies describing the presence of Actinomyces was performed.

RESULTS

Actinomyces was present in 86% of our cases and 63.3% of 371 cases presented in the literature. All of our patients and 85% of patients described in the literature had a clearly defined local focus in association with osteopathology. A clear picture of whether Actinomyces colonizes the previously necrotic bone or contributes to inflammation causing subsequent bone necrosis is lacking in the literature.

CONCLUSION

The pathogenesis of BRIOJ remains unknown; however, there seems to be a role for Actinomyces, and possibly other pathogens, in the development of osteopathology of the jaws, which is not exclusive to bisphosphonate therapy. This study supports the hypothesis that an infectious component is of utmost importance for the pathogenesis of BRIOJ.

Bisphosphonate-induced osteonecrosis of the jaw: comparison of disease extent on contrast-enhanced MR imaging, [18F] fluoride PET/CT, and conebeam CT imaging

BACKGROUND AND PURPOSE

Imaging of bisphosphonate-induced osteonecrosis of the jaw is essential for surgical planning. We compared the extent of BONJ on contrast-enhanced MR imaging, [(18)F] fluoride PET/CT, and panoramic views derived from standard conebeam CT with clinical pre- and intraoperative examinations.

MATERIALS AND METHODS

Between February 2011 and January 2012, ten subjects with written informed consent (9 women; mean, 69.6 years; range, 53-88 years) were included in this prospective ethics-board-approved study. Patients underwent CEMR imaging, [(18)F] fluoride PET/CT, and CBCT and were clinically examined pre- and intraoperatively. Surgery was performed, and BONJ was histologically confirmed in 9 patients. Location and extent of BONJ on different modalities/examinations were graphically compared (0 = no pathologic finding, 1 = smallest, 5 = largest extent of BONJ). Rank tests were used to assess overall and paired differences of ratings in 9 patients. A P value <.05 was considered statistically significant.

RESULTS

Significant differences in BONJ extent among different modalities and examinations were found (P < .001). The highest median rank was seen in PET/CT (4 ± 1.12) and CEMR imaging (4 ± 1.01), followed by intraoperative examinations (3 ± 0.71), CBCT (2 ± 0.33), and preoperative examinations (1 ± 0). No significant differences were found between PET/CT and CEMR imaging (P = .23), except when comparing PET/CT to either CBCT, pre- and intraoperative examinations (all P < .05). Preoperative examinations showed significantly less extensive disease than all other modalities/examinations (all P < .05).

CONCLUSIONS

[(18)F] fluoride PET/CT and CEMR imaging revealed more extensive involvement of BONJ compared with panoramic views from CBCT and clinical examinations.

Computer assisted maxillofacial surgery

Technical developments strongly influence modern medicine. This is especially obvious in imaging technology. Today, one of the most difficult tasks for surgeons is transferring all the available imaging information for their patients into one "complete picture". In the operation theatre, this picture then has to be applied to the patient. Computer-assisted surgery (CAS) promises to help in fulfilling this task and, thereby, to fully utilize the possibilities offered by modern imaging techniques. Today's standard procedures for CAS in the maxillofacial region are described in technical principles and clinical applications. They are evaluated and discussed based on the available literature and in light of practical experience of more than ten years in the field of CAS. In addition, an outlook is given into developments of the near future that have appeared in the current literature. While technical development is leading toward a complete integration of all processes surrounding the patient and his or her surgery, basic CAS has moved from research to clinical care. Before it is routinely used, more investigation about its effectiveness and benefits has to be done, especially since increasing medical care costs are an issue in all countries.

Oxidative stability of marine phospholipids in the liposomal form and their applications

Marine phospholipids (MPL) have attracted a great deal of attention recently as they are considered to have a better bioavailability, a better resistance towards oxidation and a higher content of eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) than oily triglycerides (fish oil) from the same source. Due to their tight intermolecular packing conformation at the sn-2 position and their synergism with α-tocopherol present in MPL extracts, they can form stable liposomes which are attractive ingredients for food or feed applications. However, MPL are still susceptible to oxidation as they contain large amounts polyunsaturated fatty acids and application of MPL in food and aquaculture industries is therefore a great challenge for researchers. Hence, knowledge on the oxidative stability of MPL and the behavior of MPL in food and feed systems is an important issue. For this reason, this review was undertaken to provide the industry and academia with an overview of (1) the stability of MPL in different forms and their potential as liposomal material, and (2) the current applications and future prospects of MPL in both food and aquaculture industries with special emphasis on MPL in the liposomal form.

High-Resolution Imaging by Fourier Transform X-ray Holography

Fourier transform x-ray holography has been used to image gold test objects with submicrometer structure, resolving features as small as 60 nanometers. The hologram-recording instrument uses coherent 3.4-nanometer radiation from the soft x-ray undulator beamline X1A at the National Synchrotron Light Source. The specimen to be imaged is placed near the first-order focal spot produced by a Fresnel zone plate; the other orders, chiefly the zeroth, illuminate the specimen. The wave scattered by the specimen interferes with the spherical reference wave from the focal spot, forming a hologram with fringes of low spatial frequency. The hologram is recorded in digital form by a charge-coupled device camera, and the specimen image is obtained by numerical reconstruction.

Covalent coupling of bilirubin to albumin

A method for covalent coupling of bilirubin to albumin is described. Human serum albumin-bilirubin (1:1 complex) has been treated with water soluble carbodiimide in order to obtain covalent coupling of bilirubin to albumin. The reaction conditions have been varied with respect to pH, reaction time and concentration of reagent to obtain the optimal coupling. The prepared albumin-bilirubin compounds were investigated by spectrophotometry, gel filtration and gel electrophoresis to ascertain the covalent nature of the bond and to characterize the products further. Gel electrophoresis and gel filtration showed that a monomer fraction could be prepared, and this fraction was a suitable material for further studies.

Properties and immunochemical reactivities of carboxy-modified human serum albumin

Seven carboxy modified and four amino modified derivatives of human serum albumin have been prepared and studied by optical rotatory dispersion measurements, gel filtration, immunoelectrophoresis, immunodiffusion and by use of an ammonium sulphate technique. It is found that carboxy groups are of major importance for the maintenance of the structure and function of human serum albumin, and that carboxy modification has a much more profound effect than amino modification has to the same relative extent.

Trinitrophenylation of the bilirubin binding site of human serum albumin

Human serum albumin has been modified with 2,4,6-trinitrobenzenesulphonic acid and picryl chloride in low ratios of reagents/albumin. The derivatives have been investigated by spectrophotometry and by thin layer chromatography of the hydrolysates in order to assess the specificity of the reagents. The same reaction conditions were used to modify albumin previously complexed with bilirubin in the ratio of 1:1. The affinity of bilirubin to the modified albumins was estimated by an improved perozidase method. It is concluded that TNBS and picryl chloride react almost quantity with epsilon-amino groups of lysine on the albumin molecule. The results also suggest that at least on TNBS reactive amino group and at least one picryl chloride reactive amino group are located in or near the high-affinity bilirubin binding site.

Differential phase contrast with a segmented detector in a scanning X-ray microprobe

Scanning X-ray microprobes are unique tools for the nanoscale investigation of specimens from the life, environmental, materials and other fields of sciences. Typically they utilize absorption and fluorescence as contrast mechanisms. Phase contrast is a complementary technique that can provide strong contrast with reduced radiation dose for weakly absorbing structures in the multi-keV range. In this paper the development of a segmented charge-integrating silicon detector which provides simultaneous absorption and differential phase contrast is reported. The detector can be used together with a fluorescence detector for the simultaneous acquisition of transmission and fluorescence data. It can be used over a wide range of photon energies, photon rates and exposure times at third-generation synchrotron radiation sources, and is currently operating at two beamlines at the Advanced Photon Source. Images obtained at around 2 keV and 10 keV demonstrate the superiority of phase contrast over absorption for specimens composed of light elements.

Fatal neurogenic pulmonary edema in a patient with progressive multiple sclerosis

We report a case of fatal neurogenic pulmonary edema in progressive multiple sclerosis (MS). The patient had one isolated relapse-like episode. Six years later progressive disease began, lasting 5 years until unexpected death during sleep. Medico-legal autopsy revealed pulmonary edema and neuropathological examination showed infiltrations with lymphocytes and microglia in the respiratory centers of the medulla. More classical demyelinated lesions were found in the white matter of spinal cord and in the gray matter of the brain along with disseminated perivascular lymphocytic infiltrates. Medullary inflammation in progressive MS may result in sudden fatal respiratory failure.

Quantitative phase imaging with a scanning transmission x-ray microscope

We obtain quantitative phase reconstructions from differential phase contrast images obtained with a scanning transmission x-ray microscope and 2.5 keV x rays. The theoretical basis of the technique is presented along with measurements and their interpretation.

Stress-induced single-polarization single-transverse mode photonic crystal fiber with low nonlinearity

We report on the design of a single-polarization single-transverse mode large mode area photonic crystal fiber. By including index-matched stress applying elements in the photonic cladding an ultra-broadband single polarization window is obtained while a large mode field area of ~700 microm(2) is maintained. Based on that design, an Yb-doped double-clad photonic crystal fiber is realized that combines low nonlinearity and single polarization properties. A first result of the high power operation using this fiber is demonstrated.

SorCS3 does not require propeptide cleavage to bind nerve growth factor

The functional properties of the Vps10p-domain receptor SorCS3 are undescribed. Here, we examine its processing and sorting in cellular transfectants, and analyze the binding of potential ligands to the purified receptor. We show that SorCS3 is synthesized as a proprotein and converted to its mature form by N-terminal propeptide cleavage in distal Golgi compartments. The propeptide is not a requirement for normal processing of the receptor and does not prevent ligands from binding to the SorCS3 precursor form. Expression of wt and chimeric receptors further suggests that SorCS3 predominates on the plasma membrane, exhibits slow internalization and does not engage in intracellular trafficking. SorCS3 emerges as a new neurotrophin binding Vps10p-domain receptor functionally distinct from its relatives Sortilin and SorLA.

Cluster analysis of soft X-ray spectromicroscopy data

Soft X-ray spectromicroscopy provides spectral data on the chemical speciation of light elements at sub-100 nm spatial resolution. When all chemical species in a specimen are known and separately characterized, existing approaches can be used to measure the concentration of each component at each pixel. In other cases (such as often occur in biology or environmental science), some spectral signatures may not be known in advance so other approaches must be used. We describe here an approach that uses principal component analysis to orthogonalize and noise-filter spectromicroscopy data. We then use cluster analysis (a form of unsupervised pattern matching) to classify pixels according to spectral similarity, to extract representative, cluster-averaged spectra with good signal-to-noise ratio, and to obtain gradations of concentration of these representative spectra at each pixel. The method is illustrated with a simulated data set of organic compounds, and a mixture of lutetium in hematite used to understand colloidal transport properties of radionuclides.

Towards optimal filtering of "standard" multifocal electroretinogram (mfERG) recordings: findings in normal and diabetic subjects

AIMS

To study the effects of two commonly used pre-amplifier filtering bandwidths on normal multifocal electroretinogram (mfERG) responses and their comparative abilities to detect retinal disease.

METHODS

103 standard mfERGs were recorded simultaneously in two channels with different pre-amplifier settings (10-100 Hz and 10-300 Hz) from one eye of each of 20 normal subjects, 17 diabetics with non-proliferative diabetic retinopathy (NPDR), and 12 diabetics without retinopathy. Signal to noise ratios (SNR) of the normal subjects' first order mfERGs were compared between channels. All subjects' amplitudes and implicit times were derived using a "template stretching" method. For comparison, implicit time was also measured using a "template sliding" method. mfERG amplitudes and implicit times were compared between the channels and among subject groups.

RESULTS

Normal mean amplitudes and implicit times were similar for the two channels. However, normal 10-100 Hz recordings had significantly higher SNR and lower intersubject variability than 10-300 Hz recordings. In NPDR, the 10-100 Hz channel identified significantly more implicit time and amplitude abnormalities. In the diabetics without retinopathy, 10-100 Hz filtering identified significantly more implicit time abnormalities than 10-300 Hz filtering. For both filter settings, diabetic implicit times were more often abnormal than amplitudes. The 10-100 Hz channel was superior for both implicit time measurements.

CONCLUSION

Standard mfERGs recorded from normal eyes and filtered 10-100 Hz contain less noise, higher SNR, and less intersubject variability than those filtered at 10-300 Hz. This underlies the finding that the 10-100 Hz filter setting identifies more retinal dysfunction than the 10-300 Hz setting.

Low-loss photonic crystal fibers for transmission systems and their dispersion properties

We report on a single-mode photonic crystal fiber with attenuation and effective area at 1550 nm of 0.48 dB/km and 130 microm(2), respectively. This is, to our knowledge, the lowest loss reported for a PCF not made from VAD prepared silica and at the same time the largest effective area for a low-loss (< 1 dB/km) PCF. We briefly discuss the future applications of PCFs for data transmission and show for the first time, both numerically and experimentally, how the group velocity dispersion is related to the mode field diameter.

Re-evaluation of the RBE of 29 kV x-rays (mammography x-rays) relative to 220 kV x-rays using neoplastic transformation of human CGL1-hybrid cells

Neoplastic transformation of human CGL1-hybrid cells was examined after exposure to 29 kV x-rays (mammography x-rays) and conventional 220 kV x-rays. The study was designed to repeat, under well-defined irradiation and culture conditions, an earlier investigation by Frankenberg et al. (Radiat Res, 2002), and to assess the validity of the high RBE values of 29 kV x-rays that had been reported. The experiments with the two types of x-rays were performed simultaneously and shared the same controls. The transformation yields with both radiation qualities were fitted to the linear-quadratic dependence on absorbed dose, and a corresponding analysis was performed for the data earlier obtained by Frankenberg et al. The transformation yields in the present study exceed those in the earlier investigation substantially, and it appears that the difference reflects inadequate feeding conditions of the cell cultures in the early experiments. The standard error bands of the dose response curves are derived and are seen to be considerably more narrow in the present results. The lowest dose of the 29 kV x-rays was 1 Gy in both studies, and at this dose the RBE vs. the conventional x-rays has now been found to be 2 with a 95% confidence interval of 1.4-2.6. The previous result was about 3.2, but the 95% confidence is very broad for these data. The estimated limit at low doses is 3.4 in the present experiments with a confidence interval that extends from less than 2 to large values.

Dominant thermodynamic role of the third independent receptor binding site in the receptor-associated protein RAP

The 39 kDa receptor-associated protein (RAP) is a three-domain escort protein in the secretory pathway for several members of the low-density lipoprotein receptor (LDLR) family of endocytic receptors, including the LDLR-related protein (LRP). The minimal functional unit of LRP required for efficient binding to RAP is composed of complement-type repeat (CR)-domain pairs, located in clusters on the extracellular part of LRP. Here we investigate the binding of full-length RAP and isolated RAP domains 1-3 to an ubiquitin-fused CR-domain pair consisting of the fifth and sixth CR domains of LRP (U-CR56). As shown by isothermal titration calorimetric analysis of simple RAP domains as well as adjoined RAP domains, all three RAP domains bind to this CR-domain pair in a noncooperative way. The binding of U-CR56 to RAP domains 1 and 2 is (at room temperature) enthalpically driven with an entropy penalty (K(D) = 2.77 x 10(-6) M and 1.85 x 10(-5) M, respectively), whereas RAP domain 3 binds with a substantially lower enthalpy, but is favored due to a positive entropic contribution (K(D) = 1.71 x 10(-7) M). The heat capacity change for complex formation between RAP domain 1 and the CR-domain pair is -1.65 kJ K(-1) mol(-1). There is an indication of a conformational change in RAP domain 3 upon binding in the surface plasmon resonance analysis of the interaction. The different mechanisms of binding to RAP domains 1 and 3 are further substantiated by the different effects on binding of mutations of the Asp and Trp residues in the LRP CR5 or CR6 domains, which are important for the recognition of several ligands.

Cubilin dysfunction causes abnormal metabolism of the steroid hormone 25(OH) vitamin D(3)

Steroid hormones are central regulators of a variety of biological processes. According to the free hormone hypothesis, steroids enter target cells by passive diffusion. However, recently we demonstrated that 25(OH) vitamin D(3) complexed to its plasma carrier, the vitamin D-binding protein, enters renal proximal tubules by receptor-mediated endocytosis. Knockout mice lacking the endocytic receptor megalin lose 25(OH) vitamin D(3) in the urine and develop bone disease. Here, we report that cubilin, a membrane-associated protein colocalizing with megalin, facilitates the endocytic process by sequestering steroid-carrier complexes on the cellular surface before megalin-mediated internalization of the cubilin-bound ligand. Dogs with an inherited disorder affecting cubilin biosynthesis exhibit abnormal vitamin D metabolism. Similarly, human patients with mutations causing cubilin dysfunction exhibit urinary excretion of 25(OH) vitamin D(3). This observation identifies spontaneous mutations in an endocytic receptor pathway affecting cellular uptake and metabolism of a steroid hormone.

Megalin-dependent cubilin-mediated endocytosis is a major pathway for the apical uptake of transferrin in polarized epithelia

Cubilin is a 460-kDa protein functioning as an endocytic receptor for intrinsic factor vitamin B(12) complex in the intestine and as a receptor for apolipoprotein A1 and albumin reabsorption in the kidney proximal tubules and the yolk sac. In the present study, we report the identification of cubilin as a novel transferrin (Tf) receptor involved in catabolism of Tf. Consistent with a cubilin-mediated endocytosis of Tf in the kidney, lysosomes of human, dog, and mouse renal proximal tubules strongly accumulate Tf, whereas no Tf is detectable in the endocytic apparatus of the renal tubule epithelium of dogs with deficient surface expression of cubilin. As a consequence, these dogs excrete increased amounts of Tf in the urine. Mice with deficient synthesis of megalin, the putative coreceptor colocalizing with cubilin, also excrete high amounts of Tf and fail to internalize Tf in their proximal tubules. However, in contrast to the dogs with the defective cubilin expression, the megalin-deficient mice accumulate Tf on the luminal cubilin-expressing surface of the proximal tubule epithelium. This observation indicates that megalin deficiency causes failure in internalization of the cubilin-ligand complex. The megalin-dependent, cubilin-mediated endocytosis of Tf and the potential of the receptors thereby to facilitate iron uptake were further confirmed by analyzing the uptake of (125)I- and (59)Fe-labeled Tf in cultured yolk sac cells.

The effects of lactation education and a prosthetic obturator appliance on feeding efficiency in infants with cleft lip and palate

OBJECTIVE

This prospective study examined the effect of lactation instruction and palatal obturation in decreasing time to feed, increasing intake, and on growth in eight breast milk bottle-fed newborn infants with cleft lip, cleft palate, or both.

DESIGN

An A, B1, C1, B2, and C2 reversal design was used with eight mothers. In A, baseline data on minutes fed by breast were recorded. In B1, baseline on minutes fed with a Haberman bottle was recorded. In C1, minutes fed following lactation education and palatal obturation were documented. Lactation education was information given to mothers to recognize infant feeding cues and to have infant-led feedings. The palatal obturator was a passive molding appliance. In B2, the obturator was removed and minutes fed noted. In C2, the obturator was returned and lactation support provided. Mothers kept feeding logs, satisfaction was assessed, and infant breast milk intake and flow rate were recorded during each study phase. Routine nutrition evaluation of weight, height, weight for height, and feed volume was completed by a registered dietitian during and following completion of the study.

RESULTS

Feeding times decreased with all infants, volume consumed increased with seven of eight infants, and flow rate increased with all infants. Mean feeding times during B1 and B2 phases (Haberman bottle only) were 34.4 and 32.3 minutes, respectively. Mean feeding times during C1 and C2 phases (obturation and lactation education) were 15.1 and 15.6 minutes. Volume of milk consumed during B1 and B2 feedings averaged 36.5 and 37 mL, compared with 67 mL and 76 mL during C1 and C2 phases. Growth as measured by height, weight gain, and weight for height during the study and the first 2 years of life compared favorably with that of children born without clefts.

CONCLUSIONS

The combined use of a palatal obturator and lactation education reduced feeding time and increased volume intake and was associated with good growth. Mothers who had desired to breast-feed elected to use the obturator to support high-volume intake, decrease infant fatigue, and provide breast milk for nutrition.