Hypertrophic pyloric stenosis

Hypertrophic pyloric stenosis, a relatively common condition, is caused by hyperplasia of the musculature of the pylorus. The diagnosis is made by a history of projectile vomiting and failure to gain weight, the observation of gastric peristaltic waves, and the palpation of a pyloric "tumor." A method of palpating this tumor is described in detail. Roentgenological studies are rarely indicated. Pylorotomy for treatment of hypertrophic pyloric stenosis was not successful until the development of necessary supporting measures. Preparation for operation consists of intravenous administration of fluids and electrolytes and sometimes serum or whole blood. The position of the tumor governs the choice between two different incisions. The operative procedure herein described is essentially that devised by Ramstedt many years ago, with modifications to facilitate the procedure.     

Special stereotactic radiotherapy techniques: procedures and equipment for treatment simulation and dose delivery

Stereotactic radiotherapy (SRT ) is a multi-step procedure with each step requiring extreme accuracy. Physician-dependent accuracy includes appropriate disease staging, multi-disciplinary discussion with shared decision-making, choice of morphological and functional imaging methods to identify and delineate the tumor target and organs at risk, an image-guided patient set-up, active or passive management of intra-fraction movement, clinical and instrumental follow-up. Medical physicist-dependent accuracy includes use of advanced software for treatment planning and more advanced Quality Assurance procedures than required for conventional radiotherapy. Consequently, all the professionals require appropriate training in skills for high-quality SRT.Thanks to the technological advances, SRT has moved from a “frame-based” technique, i.e. the use of stereotactic coordinates which are identified by means of rigid localization frames, to the modern “frame-less” SRT which localizes the target volume directly, or by means of anatomical surrogates or fiducial markers that have previously been placed within or near the target. This review describes all the SRT steps in depth, from target simulation and delineation procedures to treatment delivery and image-guided radiation therapy. Target movement assessment and management are also described.     

Generation of Murine Cardiac Pacemaker Cell Aggregates Based on ES-Cell-Programming in Combination with Myh6-Promoter-Selection

Treatment of the “sick sinus syndrome” is based on artificial pacemakers. These bear hazards such as battery failure and infections. Moreover, they lack hormone responsiveness and the overall procedure is cost-intensive. “Biological pacemakers” generated from PSCs may become an alternative, yet the typical content of pacemaker cells in Embryoid Bodies (EBs) is extremely low. The described protocol combines “forward programming” of murine PSCs via the sinus node inducer TBX3 with Myh6-promoter based antibiotic selection. This yields cardiomyocyte aggregates consistent of >80% physiologically functional pacemaker cells. These “induced-sinoatrial-bodies” (“iSABs”) are spontaneously contracting at yet unreached frequencies (400-500 bpm) corresponding to nodal cells isolated from mouse hearts and are able to pace murine myocardium ex vivo. Using the described protocol highly pure sinus nodal single cells can be generated which e.g. can be used for in vitro drug testing. Furthermore, the iSABs generated according to this protocol may become a crucial step towards heart tissue engineering.     

A Cellular Automaton Model for Tumor Dormancy: Emergence of a Proliferative Switch

Malignant cancers that lead to fatal outcomes for patients may remain dormant for very long periods of time. Although individual mechanisms such as cellular dormancy, angiogenic dormancy and immunosurveillance have been proposed, a comprehensive understanding of cancer dormancy and the “switch” from a dormant to a proliferative state still needs to be strengthened from both a basic and clinical point of view. Computational modeling enables one to explore a variety of scenarios for possible but realistic microscopic dormancy mechanisms and their predicted outcomes. The aim of this paper is to devise such a predictive computational model of dormancy with an emergent “switch” behavior. Specifically, we generalize a previous cellular automaton (CA) model for proliferative growth of solid tumor that now incorporates a variety of cell-level tumor-host interactions and different mechanisms for tumor dormancy, for example the effects of the immune system. Our new CA rules induce a natural “competition” between the tumor and tumor suppression factors in the microenvironment. This competition either results in a “stalemate” for a period of time in which the tumor either eventually wins (spontaneously emerges) or is eradicated; or it leads to a situation in which the tumor is eradicated before such a “stalemate” could ever develop. We also predict that if the number of actively dividing cells within the proliferative rim of the tumor reaches a critical, yet low level, the dormant tumor has a high probability to resume rapid growth. Our findings may shed light on the fundamental understanding of cancer dormancy.     

Stromal and epithelial networks: Temporal gene expression profiling during invasive neoplasia

The interaction between tumor cells and the stromal microenvironment is a critical factor in cancer development and progression. A recent study from the Khavari group profiled the expression changes during progression to invasion in a Ras-inducible model of human epithelial neoplasia and used network modeling to analyze the molecular interactions. Human dermis was seeded with H-Ras- and IκBα-expressing keratinocytes then grafted on to immune-deficient mice. The epithelial and stromal gene expression profiles were captured during progression from quiescent epithelial tissue to in situ neoplasia to invasive neoplasia. A subset of these altered genes was compiled into a “core tumor progression signature” (CTPS), which was shown to have clinical relevance in several cancer types. Network modeling of the CTPS revealed highly interconnected “hubs”, which was dominated by extracellular matrix-related genes, including β₁ integrin. Targeting integrin β₁ functionality reduced Ras-driven tumorigenesis in vivo and validated the network modeling strategy for predicting genes essential to neoplasia. By integrating temporal analysis of both the epithelial and stromal compartments with network modeling of molecular interactions, this work has described an effective strategy for identifying highly interconnected targets essential to tumor development.Key words: skin model, tumor invasion, microarray, network modelling, molecular interactions     

A Multi-Component Model of Hodgkin's Lymphoma

Hodgkin’s lymphoma is an example for a tumor with an extremely tight interaction of tumor cells with cells from the tumor micro-environment. These so-called bystander cells are not inert but interact actively with the tumor cells. Some of these cells support tumor growth by delivery of co-stimulating and anti-apoptotic signals (“helper cells”). Other cells (“killer cells”) are involved in the anti-tumor immune response which is obviously not efficient enough for tumor elimination. The activity of both helper cells and killer cells is regulated by additional cells in the stroma (“regulatory cells”). The dynamic behavior of such multi-component systems is difficult to predict. In the present paper we propose a model that can be used for simulation of essential features of this system. In this model, tumor growth depends on (i) presence of few cancer stem cells, (ii) co-stimulation of cancer cells by the tumor stroma, (iii) activity of regulatory cells that suppress killer cells without suppression of helper cells. The success of cytotoxic/cytostatic therapy in this model varies depending on the therapy-related toxicity for each of the cell populations. The model also allows the analysis of immunotherapeutic interventions. Under certain conditions, paradox enhancement of tumor growth can occur after therapeutic intervention. The model might be useful for the design of new treatment strategies for Hodgkin’s lymphoma and other tumors with prominent tumor-stroma interaction.     

Isolation of Mesophyll Cells from Sedum telephium Leaves

A technique is described for mechanically isolating metabolically active individual spongy mesophyll cells from the Crassulacean acid metabolism plant, Sedum telephium. Mature leaves are selected at about 2 PM when acidity is low, and three different media are used to reduce the problem of leaf acidity and to maintain isotonic conditions. The upper and lower epidermis is peeled from chilled leaves and the leaves are suspended in a buffered “soaking medium,” then gently ground with a mortar and pestle. Cells and debris are separated using a “washing medium,” with cells being filtered through a 136 micron net and collected on an 80 micron net. Cells then are suspended in a “cell suspension medium” and concentrated by centrifugation. Approximately 2 hours are required for the isolation procedure, and activity in CO₂ fixation is constant for up to 4 hours after isolation. Microscopic examination shows about 65% of the isolated cells appear intact and unplasmolyzed and are similar to leaf msophyll cells. The yield of cells on a leaf chlorophyll basis is about 1%. A light micrograph of the isolated cells is given.     

The Selection of Medical Students in Western Canada

The methods employed in the selection of medical students for the 1964-65 class of freshmen at the four Western medical schools are described and recommendations are made for improving the procedure. The structure and functions of the various selection committees varied from school to school but their prime purpose was the same—the selection of “good students” who would later become “good physicians”. Not surprisingly, academic achievement and confidence in estimating this ranked highest in importance, and while non-intellectual characteristics ranked almost as high, committee members had no confidence that they could evaluate these qualities.It is suggested that the ideal selection committee would be a “high-priority” committee consisting of six to eight members who would meet at least twice a year, have tenure of at least four years, be trained in interviewing applicants, consider Medical College Admission Test scores, review applications before each meeting, and establish research committees to investigate the students they choose.     

END RESULTS IN PAROTID TUMORS

Management of parotid tumors can be based on a clinical classification of these lesions as being either “encapsulated” or infiltrating.The Warthin tumor (papillary cystadenolymphomatosum) is a benign encapsulated tumor, often occurring multicentrically or bilaterally especially in the lower pole area of the parotid. It is characterized clinically by its softness and fluctuation in size and a high incidence in elderly men.The so-called “capsule” of well demarcated mixed and mucoepidermoid tumors is represented by a condensation of host fibrous stroma, in the interstices of which tumor cells may be present.The “encapsulated” tumors should be excised with a “shell” of uninvolved parotid tissue. To do this safely, the facial nerve should first be isolated.Total parotidectomy is necessary only if the size of the tumor, the multiplicity of recurrences, or the infiltrating nature of the tumor are such that complete eradication of the primary site must be done.Radical neck dissection is never performed electively except in the small group of nonencapsulated infiltrating primary lesions.In a series of cases of previously untreated parotid tumors treated by the method outlined, the local parotid recurrence rate was less than 1 per cent.     

Energy transfer in “parasitic” cancer metabolism: Mitochondria are the powerhouse and Achilles' heel of tumor cells

It is now widely recognized that the tumor microenvironment promotes cancer cell growth and metastasis via changes in cytokine secretion and extra-cellular matrix remodeling. However, the role of tumor stromal cells in providing energy for epithelial cancer cell growth is a newly emerging paradigm. For example, we and others have recently proposed that tumor growth and metastasis is related to an energy imbalance. Host cells produce energy-rich nutrients via catabolism (through autophagy, mitophagy and aerobic glycolysis), which are then transferred to cancer cells, to fuel anabolic tumor growth. Stromal cell derived L-lactate is taken up by cancer cells and is used for mitochondrial oxidative phosphorylation (OXPHOS), to produce ATP efficiently. However, “parasitic” energy transfer may be a more generalized mechanism in cancer biology than previously appreciated. Two recent papers in Science and Nature Medicine now show that lipolysis in host tissues also fuels tumor growth. These studies demonstrate that free fatty acids produced by host cell lipolysis are re-used via β-oxidation (β-OX) in cancer cell mitochondria. Thus, stromal catabolites (such as lactate, ketones, glutamine and free fatty acids) promote tumor growth by acting as high-energy onco-metabolites. As such, host catabolism via autophagy, mitophagy and lipolysis may explain the pathogenesis of cancer-associated cachexia and provides exciting new druggable targets for novel therapeutic interventions. Taken together, these findings also suggest that tumor cells promote their own growth and survival by behaving as a “parasitic organism.” Hence, we propose the term “parasitic cancer metabolism” to describe this type of metabolic-coupling in tumors. Targeting tumor cell mitochondria (OXPHOS and β-OX) would effectively uncouple tumor cells from their hosts, leading to their acute starvation. In this context, we discuss new evidence that high-energy onco-metabolites (produced by the stroma) can confer drug resistance. Importantly, this metabolic chemo-resistance is reversed by blocking OXPHOS in cancer cell mitochondria, with drugs like Metformin, a mitochondrial “poison.” In summary, parasitic cancer metabolism is achieved architecturally by dividing tumor tissue into at least two well-defined opposing “metabolic compartments:” catabolic and anabolic.Key words: mitochondria, cancer metabolism, autophagy, mitophagy, aerobic glycolysis, lipolysis, oxidative phosphorylation, beta-oxidation, Metformin, drug discovery, drug resistance, chemo-resistance, Warburg effect, oncometabolite, parasite, metabolic compartments     

Mitochondrial biogenesis in epithelial cancer cells promotes breast cancer tumor growth and confers autophagy resistance

Here, we set out to test the novel hypothesis that increased mitochondrial biogenesis in epithelial cancer cells would “fuel” enhanced tumor growth. For this purpose, we generated MDA-MB-231 cells (a triple-negative human breast cancer cell line) overexpressing PGC-1α and MitoNEET, which are established molecules that drive mitochondrial biogenesis and increased mitochondrial oxidative phosphorylation (OXPHOS). Interestingly, both PGC-1α and MitoNEET increased the abundance of OXPHOS protein complexes, conferred autophagy resistance under conditions of starvation and increased tumor growth by up to ~3-fold. However, this increase in tumor growth was independent of neo-angiogenesis, as assessed by immunostaining and quantitation of vessel density using CD31 antibodies. Quantitatively similar increases in tumor growth were also observed by overexpression of PGC-1β and POLRMT in MDA-MB-231 cells, which are also responsible for mediating increased mitochondrial biogenesis. Thus, we propose that increased mitochondrial “power” in epithelial cancer cells oncogenically promotes tumor growth by conferring autophagy resistance. As such, PGC-1α, PGC-1β, mitoNEET and POLRMT should all be considered as tumor promoters or “metabolic oncogenes.” Our results are consistent with numerous previous clinical studies showing that metformin (a weak mitochondrial “poison”) prevents the onset of nearly all types of human cancers in diabetic patients. Therefore, metformin (a complex I inhibitor) and other mitochondrial inhibitors should be developed as novel anticancer therapies, targeting mitochondrial metabolism in cancer cells.     

HIF1-alpha functions as a tumor promoter in cancer associated fibroblasts,and as a tumor suppressor in breast cancer cells: Autophagy drives compartment-specific oncogenesis

Our recent studies have mechanistically implicated a loss of stromal Cav-1 expression and HIF1α-activation in driving the cancer-associated fibroblast phenotype, through the paracrine production of nutrients via autophagy and aerobic glycolysis. However, it remains unknown if HIF1α-activation is sufficient to confer the cancer-associated fibroblast phenotype. To test this hypothesis directly, we stably-expressed activated HIF1α in fibroblasts and then examined their ability to promote tumor growth using a xenograft model employing human breast cancer cells (MDA-MB-231). Fibroblasts harboring activated HIF1α showed a dramatic reduction in Cav-1 levels and a shift towards aerobic glycolysis, as evidenced by a loss of mitochondrial activity, and an increase in lactate production. Activated HIF1α also induced BNIP3 and BNIP3L expression, markers for the autophagic destruction of mitochondria. Most importantly, fibroblasts expressing activated HIF1α increased tumor mass by ∼2-fold and tumor volume by ∼3-fold, without a significant increase in tumor angiogenesis. In this context, HIF1α also induced an increase in the lymph node metastasis of cancer cells. Similar results were obtained by driving NFκB activation in fibroblasts, another inducer of autophagy. Thus, activated HIF1α is sufficient to functionally confer the cancer-associated fibroblast phenotype. It is also known that HIF1α expression is required for the induction of autophagy in cancer cells. As such, we next directly expressed activated HIF1α in MDA-MB-231 cells and assessed its effect on tumor growth via xenograft analysis. Surprisingly, activated HIF1α in cancer cells dramatically suppressed tumor growth, resulting in a 2-fold reduction in tumor mass and a three-fold reduction in tumor volume. We conclude that HIF1α activation in different cell types can either promote or repress tumorigenesis. Based on these studies, we suggest that autophagy in cancer-associated fibroblasts promotes tumor growth via the paracrine production of recycled nutrients, which can directly “feed” cancer cells. Conversely, autophagy in cancer cells represses tumor growth via their “self-digestion.” Thus, we should consider that the activities of various known oncogenes and tumor-suppressors may be compartment and cell-type specific, and are not necessarily an intrinsic property of the molecule itself. As such, other “classic” oncogenes and tumor suppressors will have to be re-evaluated to determine their compartment specific effects on tumor growth and metastasis. Lastly, our results provide direct experimental support for the recently proposed “autophagic tumor stroma model of cancer.”Key words: caveolin-1, autophagy, mitophagy, the Warburg effect, tumor stroma, hypoxia, HIF1A, NFκB, compartment-specific oncogenesis, cancer-associated fibroblasts     

Vagotomy without Diarrhoea

The incidence of diarrhoea after three types of vagotomy was assessed “blind” at a gastric follow-up clinic one year after operation. Diarrhoea was recorded in 24% of patients after truncal vagotomy and pyloroplasty, in 18% after selective vagotomy and pyloroplasty, but in only 2% of patients after highly selective vagotomy without a drainage procedure. The incidence of diarrhoea was significantly less (P < 0·01) after highly selective vagotomy than after either of the other procedures.Hypertonic glucose solution given by mouth to 15 representative patients from each group and to 15 patients before operation provoked the onset of diarrhoea in 67% of the patients who had undergone truncal vagotomy and pyloroplasty, in 60% of those who had undergone selective vagotomy and pyloroplasty, in 13% of those who had undergone highly selective vagotomy without a drainage procedure, and in none of the preoperative patients. Again the difference between the “highly selective” group and the other two groups of vagotomized patients was statistically significant.It is suggested that postvagotomy diarrhoea is attributable both to unregulated gastric emptying after truncal or selective vagotomy with a drainage procedure and to the extragastric denervation produced by truncal vagotomy. “Postvagotomy” diarrhoea can be virtually eliminated by using highly selective vagotomy without a drainage procedure.     

The autophagic tumor stroma model of cancer or “battery-operated tumor growth”: A simple solution to the autophagy paradox

The role of autophagy in tumorigenesis is controversial. Both autophagy inhibitors (chloroquine) and autophagy promoters (rapamycin) block tumorigenesis by unknown mechanism(s). This is called the “Autophagy Paradox.” We have recently reported a simple solution to this paradox. We demonstrated that epithelial cancer cells use oxidative stress to induce autophagy in the tumor microenvironment. As a consequence, the autophagic tumor stroma generates recycled nutrients that can then be used as chemical building blocks by anabolic epithelial cancer cells. This model results in a net energy transfer from the tumor stroma to epithelial cancer cells (an energy imbalance), thereby promoting tumor growth. This net energy transfer is both unilateral and vectorial, from the tumor stroma to the epithelial cancer cells, representing a true host-parasite relationship. We have termed this new paradigm “The Autophagic Tumor Stroma Model of Cancer Cell Metabolism” or “Battery-Operated Tumor Growth.” In this sense, autophagy in the tumor stroma serves as a “battery” to fuel tumor growth, progression and metastasis, independently of angiogenesis. Using this model, the systemic induction of autophagy will prevent epithelial cancer cells from using recycled nutrients, while the systemic inhibiton of autophagy will prevent stromal cells from producing recycled nutrients—both effectively “starving” cancer cells. We discuss the idea that tumor cells could become resistant to the systemic induction of autophagy by the upregulation of natural, endogenous autophagy inhibitors in cancer cells. Alternatively, tumor cells could also become resistant to the systemic induction of autophagy by the genetic silencing/deletion of pro-autophagic molecules, such as Beclin1. If autophagy resistance develops in cancer cells, then the systemic inhibition of autophagy would provide a therapeutic solution to this type of drug resistance, as it would still target autophagy in the tumor stroma. As such, an anti-cancer therapy that combines the alternating use of both autophagy promoters and autophagy inhibitors would be expected to prevent the onset of drug resistance. We also discuss why anti-angiogenic therapy has been found to promote tumor recurrence, progression and metastasis. More specifically, anti-angiogenic therapy would induce autophagy in the tumor stroma via the induction of stromal hypoxia, thereby converting a non-aggressive tumor type to a “lethal” aggressive tumor phenotype. Thus, uncoupling the metabolic parasitic relationship between cancer cells and an autophagic tumor stroma may hold great promise for anti-cancer therapy. Finally, we believe that autophagy in the tumor stroma is the local microscopic counterpart of systemic wasting (cancer-associated cachexia), which is associated with advanced and metastatic cancers. Cachexia in cancer patients is not due to decreased energy intake, but instead involves an increased basal metabolic rate and increased energy expenditures, resulting in a negative energy balance. Importantly, when tumors were surgically excised, this increased metabolic rate returned to normal levels. This view of cachexia, resulting in energy transfer to the tumor, is consistent with our hypothesis. So, cancer-associated cachexia may start locally as stromal autophagy and then spread systemically. As such, stromal autophagy may be the requisite precursor of systemic cancer-associated cachexia.Key words: caveolin-1, autophagy, cancer associated fibroblasts, hypoxia, mitophagy, oxidative stress, DNA damage, genomic instability, tumor stroma, wasting (cancer cachexia), Warburg effect     

CANCER DETECTION CENTERS—The Experience to Date in California

Cancer “detection centers” (that is, centers for the examination of presumably well or asymptomatic persons) have been tried out in four different California communities during the last three years. In all instances—as in most other such centers throughout the United States—they have not been successful in restricting examination to well persons.The detection centers in California may therefore be described more accurately as “cancer examination and detection clinics.”Three of the four centers have been closed owing to the small yield of cancer cases discovered, plus the fact that the cost of operation exceeded the total available funds of the local branch of the Cancer Society. In addition, it was extremely difficult to obtain and maintain competence on the part of the professional staff in such centers.A more practical approach to the problem of earlier tumor detection would appear to be emphasis on making “every physician''s office a detection center,” and stressing the annual examination of persons over 40 years of age for tumors in the five common accessible sites. These are the tumors most readily curable today.     

Proteomic Approaches Identify Members of Cofilin Pathway Involved in Oral Tumorigenesis

The prediction of tumor behavior for patients with oral carcinomas remains a challenge for clinicians. The presence of lymph node metastasis is the most important prognostic factor but it is limited in predicting local relapse or survival. This highlights the need for identifying biomarkers that may effectively contribute to prediction of recurrence and tumor spread. In this study, we used one- and two-dimensional gel electrophoresis, mass spectrometry and immunodetection methods to analyze protein expression in oral squamous cell carcinomas. Using a refinement for classifying oral carcinomas in regard to prognosis, we analyzed small but lymph node metastasis-positive versus large, lymph node metastasis-negative tumors in order to contribute to the molecular characterization of subgroups with risk of dissemination. Specific protein patterns favoring metastasis were observed in the “more-aggressive” group defined by the present study. This group displayed upregulation of proteins involved in migration, adhesion, angiogenesis, cell cycle regulation, anti-apoptosis and epithelial to mesenchymal transition, whereas the “less-aggressive” group was engaged in keratinocyte differentiation, epidermis development, inflammation and immune response. Besides the identification of several proteins not yet described as deregulated in oral carcinomas, the present study demonstrated for the first time the role of cofilin-1 in modulating cell invasion in oral carcinomas.     

Clinical diagnosis of pyloric stenosis: a declining art.

OBJECTIVE--To assess whether diagnostic imaging of pyloric stenosis has made a difference in rapidity of diagnosis, duration of pre-operative hydration, and length of stay in hospital. DESIGN--Chart review of infants with confirmed diagnosis of pyloric stenosis. SETTING--Paediatric teaching hospital. SUBJECTS--215 infants with a confirmed diagnosis of pyloric stenosis seen during 1974-7 and 187 infants with pyloric stenosis seen during 1988-91. MAIN OUTCOME MEASURES--State of hydration on admission, time between presentation to hospital and a definite diagnosis, techniques used to make the diagnosis, whether a pyloric mass was felt before or after an imaging procedure, time between presentation and surgery, and length of stay in hospital. RESULTS--The average age at presentation was 40 days in both groups. A pyloric mass was palpated either without or before an imaging study in 87% (187/215) of cases during 1974-7 but in only 49% (91/187) during 1988-91. The use of barium meal examination and ultrasonography increased from 20% (42/215) of cases during 1974-7 to 61% (114/187) during 1988-91. There were no significant differences between the two groups in the time taken to establish a diagnosis, the mean duration of preoperative treatment, or the length of stay in hospital (after allowance for the decline in average length of stay of all hospital patients between the two periods). CONCLUSIONS--An increased use of diagnostic imaging for pyloric stenosis did not lead to earlier diagnosis or better management. While imaging is important in identifying pyloric stenosis in difficult cases, increasing reliance on imaging has reduced doctors'' skills in diagnosing pyloric stenosis clinically.     

An Imputation Approach for Oligonucleotide Microarrays

Oligonucleotide microarrays are commonly adopted for detecting and qualifying the abundance of molecules in biological samples. Analysis of microarray data starts with recording and interpreting hybridization signals from CEL images. However, many CEL images may be blemished by noises from various sources, observed as “bright spots”, “dark clouds”, and “shadowy circles”, etc. It is crucial that these image defects are correctly identified and properly processed. Existing approaches mainly focus on detecting defect areas and removing affected intensities. In this article, we propose to use a mixed effect model for imputing the affected intensities. The proposed imputation procedure is a single-array-based approach which does not require any biological replicate or between-array normalization. We further examine its performance by using Affymetrix high-density SNP arrays. The results show that this imputation procedure significantly reduces genotyping error rates. We also discuss the necessary adjustments for its potential extension to other oligonucleotide microarrays, such as gene expression profiling. The R source code for the implementation of approach is freely available upon request.     

A New Germfree Chicken Cage—Characteristics and Use

A new germfree chicken cage for rearing chicks up to 3 or 4 weeks of age has been designed and is in use at the University of Missouri. The cage and the accessory parts, the small magnet and hinged door, the “Bactytector,” the built-in air filter assembly, and the glass top with connecting air outlet filter have been described in detail. The complete operating procedure for sterilizing the cage and diet and the method of adding sterile embryonated eggs have been outlined. Data on the effectiveness of the cage as a physical barrier to microbes have been presented.