The Role of Nerve Growth Factor in Maintaining Proliferative Capacity, Colony-Forming Efficiency, and the Limbal Stem Cell Phenotype

Nerve growth factor (NGF) has demonstrated great benefit in the treatment of neurotrophic corneal ulcers. There is evidence for multiple modes of action in promoting corneal healing, but only indirect evidence exists for NGF's effects on limbal stem cells (LSCs). Understanding the role of NGF in LSC biology will improve our understanding of paracrine regulation of the limbal niche and the design of stem cell‐based therapies for conditions such as LSC deficiency. In this article, we studied the regulation of NGF signaling components during LSC differentiation and the role of NGF in LSC proliferation and maintenance of the stem cell phenotype. LSC differentiation was induced by prolonged (40 day) culture which resulted in a significant increase in cell size, decrease in colony‐forming efficiency and expression of putative LSC markers. A protein microarray measuring expression of 248 signaling proteins indicated the low affinity NGF receptor p75^NTR to be the most downregulated protein upon differentiation. Further confirmation by Western blotting and real‐time quantitative polymerase chain reaction indicated that NGF and p75^NTR are expressed in early LSC cultures and downregulated upon differentiation. LSC cultures grown in the presence of anti‐NGF antibody showed decreased colony‐forming efficiency, DNA replication and expression of putative LSC markers ABCG2 and C/EBPδ. Supplementation of LSC culture medium with NGF extended the life span of LSC cultures in vitro and increased the expression of putative LSC markers ΔNp63α and ABCG2. Taken together, our data indicate that NGF signaling is a key promoter of LSC proliferation, colony‐forming efficiency, and a maintainer of the LSC phenotype. stem cells2019;37:139–149

Obsessive compulsive Personality Disorder and Autism Spectrum Disorder Traits in the Obsessive-compulsive Disorder Clinic

Introduction

Obsessive Compulsive Personality Disorder (OCPD) is a common, highly co-morbid disorder. Subjected to comparatively little research, OCPD shares aspects of phenomenology and neuropsychology with obsessive-compulsive spectrum disorders and neurodevelopmental disorders such as autism spectrum disorder (ASD). A greater understanding of this interrelationship would provide new insights into its diagnostic classification and generate new research and treatment heuristics.

Aims

To investigate the distribution of OCPD traits within a cohort of OCD patients. To evaluate the clinical overlap between traits of OCPD, OCD and ASD, as well as level of insight and treatment resistance.

Method

We interviewed 73 consenting patients from a treatment seeking OCD Specialist Service. We evaluated the severity of OCPD traits (Compulsive Personality Assessment Scale; CPAS), OCD symptoms (Yale–Brown Obsessive Compulsive Scale; Y-BOCS), ASD traits (Adult Autism Spectrum Quotient; AQ) and insight (Brown Assessment of Beliefs Scale; BABS).

Results

Out of 67 patients, 24 (36%) met DSM-IV criteria for OCPD, defined using the CPAS. Using Pearson's test, CPAS scores significantly (P < 0.01) correlated with total AQ and selected AQ domains but not with BABS. Borderline significant correlation was observed with Y-BOCS (P = 0.07). OCPD was not over-represented in a highly resistant OCD subgroup.

Conclusion

Disabling OCPD traits are common in the OCD clinic. They strongly associate with ASD traits, less strongly with OCD severity and do not appear related to poor insight or highly treatment-resistant OCD. The impact of OCPD on OCD treatment outcomes requires further research.

Disclosure of interest

This work did not receive funding from external sources. Over the past few years, Dr. Fineberg has received financial support in various forms from the following: Shire, Otsuka, Lundbeck, Glaxo-SmithKline, Servier, Cephalon, Astra Zeneca, Jazz pharmaceuticals, Bristol Myers Squibb, Novartis, Medical Research Council (UK), National Institute for Health Research (UK), Wellcome Foundation, European College of Neuropsychopharmacology, UK College of Mental Health Pharmacists, British Association for Psychopharmacology, International College of Obsessive-Compulsive Spectrum Disorders, International Society for Behavioural Addiction, World Health Organization, Royal College of Psychiatrists.

Overlap of obsessive-compulsive personality disorder and autism spectrum disorder traits among OCD outpatients: an exploratory study

Background: Whereas the phenomenology of obsessive-compulsive personality disorder (OCPD) shows similarities to that of obsessive compulsive and related disorders (OCRDs) as well as with autism spectrum disorder (ASD), the relationship between these disorders is poorly understood.Aims: Within a clinical sample, we aimed to investigate the distribution of OCD, OCPD and ASD symptoms and traits and their interrelationship, as well as to evaluate insight and treatment refractoriness.Methods: Consecutive adult OCD outpatients were assessed for OCPD traits (Compulsive Personality Assessment Scale (CPAS)), OCD symptoms (Yale-Brown Obsessive Compulsive Scale (Y-BOCS)), ASD traits (Autism Spectrum Quotient (AQ)), insight (Brown Assessment of Beliefs Scale (BABS)) and treatment resistance (clinical records). Those scoring highly on the AQ underwent a diagnostic interview for ASD.Results: Sixty-seven consenting individuals completed the CPAS, BABS and AQ, and 65 completed the Y-BOCS. Twenty-four patients (35.8%) were diagnosed with OCPD. Patients with OCPD were less likely to be employed (p=.04). They demonstrated elevated AQ scores (p=.004) and rates of ASD diagnosis (54.2%) (p <.001). OCPD traits (CPAS) showed a highly significant correlation with ASD traits (AQ) (p<.001), and no association with Y-BOCS, BABS or treatment resistance.Conclusions: In an OCD cohort limited by small size, OCPD associated strongly with unemployment and ASD, with implications for diagnosis, treatment and outcome.KEY POINTSClinicians should exercise a high level of vigilance for OCPD and ASD in patients presenting with obsessive compulsive symptoms.The presence of OCPD may indicate a likelihood of disabling ASD traits, including cognitive inflexibility, poor central coherence and poor social communication.These neuropsychological factors may require separate clinical intervention strategies.

Patient priorities in herpes simplex keratitis

Objective

Herpes simplex keratitis (HSK) is a sight-threatening disease and a leading cause of infectious corneal blindness. Involving patients in setting the research agenda maximises patient benefit and minimises research waste. With no published patient involvement exercises, patients' priorities in HSK are unclear. The objective of this study is to explore patients' priorities for research in HSK.

Methods

A literature review of publications in the year preceding recruitment of patients identified nine domains of research interest. A questionnaire was sent to participants asking them to rank these in order of priority. The ranking results were given a weighted-average score, and a thematic analysis was undertaken for the narrative data.

Results

Thirty-seven patients participated in the survey. Top priorities for patients were risk factors for recurrence of infection, diagnostic tests and treatment failure. The narrative data revealed three key clinical needs: difficulties in long-term symptom control, the need for rapid access care in acute infection and the desire for more accessible information.

Conclusion

This study highlighted three major issues in our current approach to HSK. First, there may be a misalignment between research efforts and patient priorities. Second, high-quality patient information is not widely available. This may hamper patients' abilities to make informed decisions and contribute towards research. Third, clinical service priorities are of equal importance to patients as research. Researchers and clinicians are encouraged to address both needs in parallel.

Toxic epidermal necrolysis: the red eye and red herrings in casualty

A 38-year-old woman presented to casualty with bilateral red eyes associated with a recent upper respiratory tract infection. This was initially diagnosed as conjunctivitis, however systemic review revealed an erythematous facial and skin rash, mildly swollen lips and mild swallowing difficulties. The patient was referred for an urgent medical assessment, by which time she was found to have erythema affecting 54% of her body surface area and diagnosed with suspected toxic epidermal necrolysis (TEN). She rapidly deteriorated over 24 hours with a spreading blistering skin rash and airway compromise requiring urgent intubation and admission to the intensive treatment unit (ITU). Subsequent skin biopsies confirmed the diagnosis of TEN, attributed to recent use of ibuprofen. Treatment included broad-spectrum antibiotics and high-dose corticosteroids. The patient had a prolonged hospital stay and developed severe scarring of the ocular surface. She was discharged home and remains under continuing outpatient follow-up with ophthalmology and dermatology teams.

Use of antibiotics and the prevalence of antibiotic-associated diarrhoea in patients with spinal cord injuries: an international, multi-centre study

BACKGROUND

Little is known about the use of antibiotics and the extent of antibiotic-associated diarrhoea (AAD) in patients with spinal cord injuries (SCIs).

AIMS

To record the use of antibiotics, establish the prevalence of AAD and Clostridium difficile infection (CDI), and assess if there was any seasonal variation in antibiotic use and incidence of AAD in patients with SCIs.

METHODS

A retrospective study was conducted in six European SCI centres between October 2014 and June 2015. AAD was defined as two or more watery stools (Bristol Stool Scale type 5, 6 or 7) over 24 h.

FINDINGS

In total, 1267 adults (median age 54 years, 30.7% female) with SCIs (52.7% tetraplegia, 59% complete SCI) were included in this study. Among the 215 (17%) patients on antibiotics, the top three indications for antibiotics were urinary tract infections (UTIs), infected pressure ulcers and other skin infections. Thirty-two of these 215 (14.9%) patients developed AAD and two patients out of the total study population (2/1267; 0.16%) developed CDI. AAD was more common in summer than in spring, autumn or winter (30.3% vs 3.8%, 7.4% and 16.9%, respectively; P<0.01). AAD was associated with age ≥65 years, tetraplegia, higher body mass index, hypoalbuminaemia, polypharmacy, multiple antibiotic use and high-risk antibiotic use. Summer and winter seasons and male sex were identified as independent predictors for the development of AAD.

CONCLUSION

This survey found that AAD is common in patients with SCIs, and UTI is the most common cause of infection. Summer and winter seasons and male sex are unique predictors for AAD. Both AAD and UTIs are potentially preventable; therefore, further work should focus on preventing the over-use of antibiotics, and developing strategies to improve hospital infection control measures.

Vitamin A deficiency due to chronic malabsorption: an ophthalmic manifestation of a systemic condition

A 47-year-old woman presented with a 4-week history of progressive loss of vision, first manifesting as night blindness. Additionally, the patient reported frequent severe episodes of diarrhoea over the past month. Her medical history included end-stage renal failure for which she was currently on haemodialysis after a failed renal transplant, chronic pancreatitis and autonomic diabetes mellitus. Ophthalmological examination revealed severe bilateral corneal xerosis, bilateral Bitot's spots and inferior ulceration of the right cornea. A diagnosis of xerophthalmia due to vitamin A deficiency was made, most likely due to the presence of small intestinal bacterial overgrowth and the patient's chronic malabsorptive state. Standard management using oral vitamin A tablets was ineffective, resulting in the patient requiring intravenous supplementation. The extent of visual deterioration on presentation and the difficulties encountered managing the patient resulted in the patient's vision failing to improve.

Successful application of ex vivo expanded human autologous oral mucosal epithelium for the treatment of total bilateral limbal stem cell deficiency

Ocular surface reconstruction with ex vivo expanded limbal stem cells (LSCs) is a widely used clinical treatment for patients with limbal stem cell deficiency (LSCD). This is not applicable to patients with bilateral LSCD where there are no remaining LSCs. Cultivated oral mucosa epithelium (OME) has been used as an alternative source of autologous epithelial stem cells for ocular reconstruction in few clinical trials. However, successful generation of stratified OME epithelium has only been achieved in the presence of animal feeder cells and/or animal-derived products in the culture media, likely to contribute to increased risk of pathogen transmission and graft rejection. In this study, we report generation of multilayered OME epithelium that shares many of the characteristics of corneal epithelium using a fully compliant good manufacturing practice, feeder- and animal product-free method. Proof of concept was achieved by transplantation of autologous ex vivo expanded OME in two patients with histologically confirmed bilateral total LSCD that resulted in successful reversal of LSCD in the treated eye up to 24 months.

Femtosecond LASIK retreatment using side cutting only

PURPOSE

To present visual and refractive outcomes in 11 eyes that underwent femtosecond LASIK and subsequent retreatment with flap lifting using only side cutting.

METHODS

Seven patients (11 eyes) with a mean age of 30.55±5.42 years (range: 24 to 39 years) underwent retreatment 18.18±5.41 months (range: 12 to 26 months) after primary LASIK treatment with side cutting only using a femtosecond laser for the correction of residual refractive error.

RESULTS

Mean follow-up after retreatment was 7.72±1.48 months (range: 6 to 10 months). No intra- or postoperative complications were found after LASIK retreatment. Uncorrected distance visual acuity (UDVA) improved in all patients. Mean UDVA improved from 0.54±0.12 (decimal scale) (range: 0.4 to 0.7) preoperatively to 0.99±0.03 (range: 0.9 to 1.0) after retreatment. No patient lost lines of corrected distance visual acuity.

CONCLUSIONS

Retreatment using a femtosecond laser to create only a side cut is an effective modality to treat residual refractive errors in postoperative LASIK patients.

The effect of static cyclotorsion compensation on refractive and visual outcomes using the Schwind Amaris laser platform for the correction of high astigmatism

PURPOSE

To compare the refractive and visual outcomes using the Schwind Amaris excimer laser in patients with high astigmatism (>1D) with and without the static cyclotorsion compensation (SCC) algorithm available with this new laser platform.

METHODS

70 consecutive eyes with ≥1D astigmatism were randomized to treatment with compensation of static cyclotorsion (SCC group- 35 eyes) or not (control group- 35 eyes). A previously validated optimized aspheric ablation algorithm profile was used in every case. All patients underwent LASIK with a microkeratome cut flap.

RESULTS

The SCC and control group did not differ preoperatively, in terms of refractive error, magnitude of astigmatism or in terms of cardinal or oblique astigmatism. Following treatment, average deviation from target was SEq +0.16D, SD±0.52 D, range -0.98 D to +1.71 D in the SCC group compared to +0.46 D, SD±0.61 D, range -0.25 D to +2.35 D in the control group, which was statistically significant (p<0.05). Following treatment, average astigmatism was 0.24 D (SD±0.28 D, range -1.01 D to 0.00 D) in the SCC group compared to 0.46 D (SD±0.42 D, range -1.80 D to 0.00 D) in the control group, which was highly statistically significant (p<0.005). There was no statistical difference in the postoperative uncorrected vision when the aspheric algorithm was used although there was a trend to increased number of lines gained in the SCC group.

CONCLUSIONS

This study shows that static cyclotorsion is accurately compensated for by the Schwind Amaris laser platform. The compensation of static cyclotorsion in patients with moderate astigmatism produces a significant improvement in refractive and astigmatic outcomes than when not compensated.

Successful clinical implementation of corneal epithelial stem cell therapy for treatment of unilateral limbal stem cell deficiency

The corneal epithelium is maintained by a population of stem cells known as limbal stem cells (LSCs) due to their location in the basal layer of the outer border of the cornea known as the limbus. Treatment of limbal stem cell deficiency (LSCD) has been achieved with transplantation of ex vivo expanded LSCs taken from a small biopsy of limbus. This is a relatively new technique, and as such, specific national or international guidance has yet to be established. Because of the lack of such specific guidance, our group has sought to minimize any risk to the patient by adopting certain modifications to the research methodologies in use at present. These include the replacement of all non-human animal products from the culture system and the production of all reagents and cultures under Good Manufacturing Practice conditions. In addition, for the first time, a strictly defined uniform group of patients with total unilateral LSCD and no other significant ocular conditions has been used to allow the success or failure of treating LSCD to be attributable directly to the proposed stem cell therapy. A prospectively designed study with strict inclusion and exclusion criteria was used to enroll patients from our database of patients with unilateral LSCD. Eight eyes of eight consecutive patients with unilateral total LSCD treated with ex vivo expanded autologous LSC transplant on human amniotic membrane (HAM) with a mean follow-up of 19 (RANGE) months were included in the study. Postoperatively, satisfactory ocular surface reconstruction with a stable corneal epithelium was obtained in all eyes (100%). At last examination, best corrected visual acuity improved in five eyes and remained unchanged in three eyes. Vision impairment and pain scores improved in all patients (p < .05). This study demonstrates that transplantation of autologous limbal epithelial stem cells cultured on HAM without the use of non-human animal cells or products is a safe and effective method of reconstructing the corneal surface and restoring useful vision in patients with unilateral total LSCD.

Stem cell therapies for ocular surface disease

Transparency of the cornea on the front surface of the eye is essential for vision. A variety of blinding ocular surface diseases involve the cornea. This review focusses on vision loss caused by disruption of the integrity and function of the outermost corneal layer (the epithelium) and the stem-cell-based therapeutic strategies in use and under development to restore sight in affected patients.

Loss of corneal epithelial stem cell properties in outgrowths from human limbal explants cultured on intact amniotic membrane

Background: The corneal epithelium is renewed by stem cells located at the limbus, the so-called limbal stem cells (LSCs). Absence, damage or loss of the LSC population leads to the painful and blinding condition of LSC deficiency (LSCD). Ex vivo expansion of LSCs is an increasingly well recognized treatment modality for LSCD. One method of ex vivo expansion of LSCs involves the culture of limbal explants on amniotic membrane (AM). The purpose of this study was to analyze the outgrowths from human cadaveric limbal explants cultured on AM for properties associated with LSCs. In particular, the expression of putative stem cell markers and the colony-forming efficiency of the different zones of the outgrowth were studied. Methods: The limbal explants were expanded in the standard way used for clinical transplantation and the outgrowths were divided into three zones depending on proximity to the explant (inner, middle and outer zones). The colony-forming efficiencies (CFEs) of cells from each zone were calculated. In addition, the expression of ΔNp63, ABCG2 (both putative positive LSC markers) and cytokeratin K3 (marker of corneal differentiation) were assessed using quantitative reverse transcription PCR (RT-PCR). Immunohistochemistry on paraffin-embedded sections was also performed to demonstrate protein localization and allow further confirmation of the quantitative RT-PCR results. Results: Successful cultures for both the explant outgrowths and the CFE calculations were obtained in every case. CFE showed a successive decline in zones further away from the explant (p < 0.00005). Quantitative RT-PCR revealed that the expression of the positive putative LSC markers ΔNp63 and ABCG2 also showed a steady decrease in the zones furthest from the explant (p < 0.05 and p < 0.005, respectively). The expression of cytokeratin K3 was increased in zones furthest from the explant (p < 0.005). Immunohistochemistry on paraffin-embedded sections of intact ex vivo-expanded limbal epithelium for the putative positive marker p63 and cytokeratin K3 confirmed the findings of the quantitative RT-PCR and CFE results. Conclusions: We demonstrate for the first time that outgrowths from human limbal explants, a widely used technique in ex vivo expansion of LSCs for clinical transplantation, show a steady decline in a wide range of stem cell properties with distance from the central explant. These findings support the importance of proximity of stem cells to their niche environment in maintaining their undifferentiated state. These findings suggest the need for modifications of existing techniques to ensure maximum numbers of LSCs following ex vivo expansion protocols, which will then ensure the success of subsequent engraftment.

Differentiation of human embryonic stem cells into corneal epithelial-like cells by in vitro replication of the corneal epithelial stem cell niche

Human embryonic stem cells (hESCs) are pluripotent cells capable of differentiating into any cell type of the body. It has long been known that the adult stem cell niche is vital for the maintenance of adult stem cells. The cornea at the front of the eye is covered by a stratified epithelium that is renewed by stem cells located at its periphery in a region known as the limbus. These so-called limbal stem cells are maintained by factors within the limbal microenvironment, including collagen IV in basement membrane and limbal fibroblasts in the stroma. Because this niche is very specific to the stem cells (rather than to the more differentiated cells) of the corneal epithelium, it was hypothesized that replication of these factors in vitro would result in hESC differentiation into corneal epithelial-like cells. Indeed, here we show that culturing of hESC on collagen IV using medium conditioned by the limbal fibroblasts results in the loss of pluripotency and differentiation into epithelial-like cells. Further differentiation results in the formation of terminally differentiated epithelial-like cells not only of the cornea but also of skin. Scanning electron microscopy shows that some differences exist between hESC-derived and adult limbal epithelial-like cells, necessitating further investigation using in vivo animal models of limbal stem cell deficiency. Such a model of hESC differentiation is useful for understanding the early events of epithelial lineage specification and to the eventual potential application of epithelium differentiated from hESC for clinical conditions of epithelial stem cell loss. Disclosure of potential conflicts of interest is found at the end of this article.

"Cryoanalgesic preparation" before local anaesthetic injection for lid surgery

INTRODUCTION

Lid surgery under local anaesthetic is commonplace in ophthalmic practise. The most distressing part of the surgery for the patient is often the injection of local anaesthetic into the sensitive lid skin. Various methods like pre-injection warming of the anaesthetic agent, buffering pH levels, varying agents used, and using thinner gauge needles have been tried to reduce pain levels. Cooling of tissue is known to have anaesthetic properties and has been proposed as a substitute to injection of local anaesthetic in certain surgical procedures. In this study we use the anaesthetic property of cooling, as a pre local anaesthetic injection procedure ("Cryo-preparation"). The anaesthetic injection induced discomfort with and without "cryo-preparation" was then assessed.

METHODS

Thirty-nine patients aged 13-85 years (mean = 50, s.d. = 19) were randomly allocated and assessed. Twenty-two patients underwent local lid anaesthetic infiltration with "cryo-preparation," and 17 without. Pain monitoring was performed subjectively and objectively by scoring systems. Results were analysed using unpaired two tailed t-test on Microsoft Excel.

RESULTS

Significant reduction in injection pain with cryo-preparation (24.6% reduction in score) was achieved (statistically significant p = 0.039). Surgical anaesthesia was complete in all cases.

CONCLUSION

The study shows that "cryopreparation" by local ice application immediately prior to local anaesthetic injection reduces the sensitivity to the injection by a significant 24.6%. Thus while all the advantages of good analgesia are obtained from the injection, the distressing discomfort is reduced. This study serves as a pilot, in demonstrating a novel method of pain control for lid surgery.

Ambulatory inguinal hernia repair with prolene hernia system (PHS)

Study was conducted to evaluate the feasibility and benefits of inguinal hernia repair with prolene hernia system (PHS) mesh under local anaesthesia as a day surgery procedure in a multinational society of United Arab Emirates. One hundred and seventy-eight inguinal hernias in 172 consecutive adults of whom 154 (89.5%) fitted the criteria of inclusion in the day-case surgery settings were operated upon including one early recurrence. Conversion from local to general anaesthesia was required in five (2.8%) patients. The mean operation time was 65 min, including the anaesthesia injection. The mean hospital stay was 2.1 days for all patients and 1.01 days for those who fitted in the ambulatory surgery program. Inguinal hernia repair using the PHS technique under local anaesthesia could be mastered by many of the surgeons in our hospital with minimal morbidity and short hospital stay with a potential to lessen recurrence.

Antisense-mediated depletion of p300 in human cells leads to premature G1 exit and up-regulation of c-MYC

The cAMP-response element-binding protein (CREB)-binding protein and p300 are two highly conserved transcriptional coactivators and histone acetyltransferases that integrate signals from diverse signal transduction pathways in the nucleus and also link chromatin remodeling with transcription. In this report, we have examined the role of p300 in the control of the G(1) phase of the cell cycle in nontransformed immortalized human breast epithelial cells (MCF10A) and fibroblasts (MSU) by using adenovirus vectors expressing p300-specific antisense sequences. Quiescent MCF10A and MSU cells expressing p300-specific antisense sequences synthesized p300 at much reduced levels and exited G(1) phase without serum stimulation. These cells also showed an increase in cyclin A and cyclin A- and E-associated kinase activities characteristic of S phase induction. Further analysis of the p300-depleted quiescent MCF10A cells revealed a 5-fold induction of c-MYC and a 2-fold induction of c-JUN. A direct target of c-MYC, CAD, which is required for DNA synthesis, was also found to be up-regulated, indicating that up-regulation of c-MYC functionally contributed to DNA synthesis. Furthermore, S phase induction in p300-depleted cells was reversed when antisense c-MYC was expressed in these cells, indicating that up-regulation of c-MYC may directly contribute to S phase induction. Adenovirus E1A also induced DNA synthesis and increased the levels of c-MYC and c-JUN in serum-starved MCF10A cells in a p300-dependent manner. Our results suggest an important role of p300 in cell cycle regulation at G(1) and raise the possibility that p300 may negatively regulate early response genes, including c-MYC and c-JUN, thereby preventing DNA synthesis in quiescent cells.

Beneficial effect of a bile acid resin binder on enteral feeding induced diarrhea

OBJECTIVES

Diarrhea is a complication of enteral feeding, occurring in up to 68% of critically ill patients. We hypothesized that prolonged fasting results in abnormal bile acid homeostasis. Subsequent enteral feeding then causes a relative luminal excess of bile acids, which leads to choleretic diarrhea. Hence, diarrhea induced by enteral feeding should improve with the use of a bile acid binding agent, such as Colestid Granules.

METHODS

We evaluated the effect of Colestid on enteral feeding-induced diarrhea in a double-blind placebo-controlled study. Nineteen patients who were nil per os (NPO) for 5 days before initiation of enteral feeding were enrolled in the study and treatment continued for 7 days. The severity and frequency of diarrhea were quantified. Fecal bile acids were measured enzymatically. Stool nutrient loss was measured by fat extraction, microkjeldahl determination of nitrogen, and bomb calorimetry of dried fecal specimens.

RESULTS

Enteral feeding resulted in a high frequency of diarrhea (95%) at some time during the observation period. The majority of episodes of diarrhea in both groups were of low volume. Colestid significantly decreased the prevalence and severity of diarrhea. Colestid had no significant effect on fecal calorie or nutrient losses. The average bile acid concentration in the stool increased significantly after enteral feeding.

CONCLUSION

Enteral feeding-induced diarrhea is, at least in part, due to malabsorption of bile acids. The bile acid resin binding agent Colestid improves diarrhea induced by enteral feeding.

Efficient mammalian protein synthesis requires an intact F-actin system

The mammalian protein synthesizing system is highly organized in vivo, and its substrate, tRNA, is channeled throughout the translation process. However, the cellular components responsible for this organization are not known. To examine this question a series of studies was carried out using intact and permeabilized Chinese hamster ovary cells. We show that cold shock dramatically reduces the protein synthetic capacity of these cells by as much as 95%. The loss of activity can be reversed by a short recovery period under conditions that allow energy metabolism to occur; transcription and translation during the recovery period are not needed. While individual components of the translation apparatus are not inactivated by the cold shock, the supramolecular organization of the system appears to be altered and F-actin levels are found to decrease. Resumption of protein synthesis during the recovery period coincides closely with the restoration of F-actin to normal levels. Moreover, disruption of actin filaments, but not microtubules, also leads to a major reduction in translation. These data support the conclusion that the cellular microfilament network plays an important role in the structure and function of the translation system and that perturbations of this network can have profound effects on protein synthesis.

beta-Carotene supplementation results in an increased serum and colonic mucosal concentration of beta-carotene and a decrease in alpha-tocopherol concentration in patients with colonic neoplasia

The aim of this study was to evaluate the colonic mucosal beta-carotene (BC) concentration following supplementation with BC and to determine if an increase in BC concentration influences vitamin E (alpha-tocopherol) status. The concentration of BC and alpha-tocopherol was assessed in serum and colonic tissue obtained from subjects with a history of colonic polyps or resected cancer (Dukes A, B1, or B2). Serum and mucosal biopsy samples were obtained prior to and following 3 months daily p.o. supplementation with 30 mg of BC or placebo. The concentration of BC was significantly increased in serum and colonic mucosa from both polyp and cancer subjects following supplementation as compared to presupplementation values and values from subjects receiving a placebo. The concentration of alpha-tocopherol in serum from cancer subjects was significantly decreased in samples obtained at the end of 3 months of BC supplementation as compared to placebo-matched controls. In BC-supplemented polyp subjects the tissue concentration of alpha-tocopherol was also significantly decreased relative to presupplementation values. The results indicate that BC supplementation does result in a significant accumulation of BC in the colonic mucosa but that the alpha-tocopherol concentration in both serum and colonic tissue may be compromised by an increased intake of BC. The mechanism for the decrease in alpha-tocopherol in conjunction with the increase in BC will require further study in order to develop strategies which will prevent vitamin E deficiency in BC-supplemented individuals.

Fatal radiation hepatitis: a case report and review of the literature

A case of fatal radiation hepatitis occurring after treatment with 2200 rad given by the moving strip technique is presented. This fatality occurred in a 28-year-old woman with persistent ovarian carcinoma despite prolonged chemotherapy. Scans of the liver using computerized tomography, 99mTc sulfur colloid, and 99mTc diisopropyl iminodiacetic acid showed abnormalities only in sulfur colloid uptake and these resolved late in the course. Death was caused by progressive hepatic and renal failure. Postmortem examination showed changes typical of radiation hepatitis. Only 32 cases of radiation hepatitis have been previously reported and they are reviewed. The possible role of prolonged prior chemotherapy in enhancing sensitivity to radiotherapy is considered.