Is the changing landscape of fellowship recruitment during COVID-19 here to stay?

BACKGROUND

The 2020 Pediatric Surgery (PS) fellowship selection process was heavily impacted by the COVID-19 pandemic. A review of lessons learned can help determine best practices for the future. The purpose of the study was to analyze the virtual interview experience and assess opportunities to improve the post-pandemic fellowship recruitment process.

STUDY DESIGN

Using a 28-question survey of Program Directors (PDs) of PS fellowships as well as a 44-question survey of applicants to PS fellowships in the US and Canada, we gathered information on the recruitment process during the COVID-19 pandemic (2020). Dichotomous, multiple choice and open-ended questions about the changes in process, platforms used, format, comparison to on-site interviews and overall satisfaction were used for objective and subjective feedback.

RESULTS

A 95% participation rate was recorded for the PD survey. 24 out of 55 programs (44%) changed their on-site interviews to virtual format due to the pandemic. Most PDs described their overall impression of virtual interviews as satisfactory (66%, 16/24) and did not have an impact on the applicant's success in the match (35/54; 65%). About 50% of PDs preferred to have on-site interviews with virtual screening in the future. While the participation rate from applicants was much less (26 of 70), responses confirmed our survey results. Majority preferred on-site interviews (17/26), 6 of which preferred virtual screening followed by on-site interviews.

CONCLUSION

Components of virtual screening and interviews were found to have benefits financially and from both time and stress perspectives, and thus might survive past the pandemic. LEVELS OF EVIDENCE LEVEL IV: .

Success in pediatric surgery: An updated survey of Program Directors 2020

BACKGROUND

One of the most competitive surgical sub-specialty fellowships remains Pediatric Surgery (PS), which requires candidates to develop a strong and research-oriented curriculum vitae. Although some objective factors of matriculation are known, factors for the interview selection and ranking per the program directors (PDs) have not been reviewed in over a decade.

METHODS

A web-based survey of US and Canadian PS program directors (PDs) (n = 58) was used to evaluate a comprehensive list of factors in the selection criteria for PS fellowships. A mix of dichotomous, ranking, five-point Likert scale, and open-ended questions evaluated applicant characteristics, ABSITE scores, research productivity, interview day, and rank order criteria.

RESULTS

Fifty-five programs responded to the survey for a 95% participation rate. PDs desired an average of two years in dedicated research and weighted first authorship and total number of publications heavily. Only 38% of programs used an ABSITE score cutoff for offering interviews; however, the majority agreed that an overall upward trend was important. Quality letters of recommendation, especially from known colleagues, carried weight when deciding to offer interviews. Interview performance, being a team player, observed interpersonal interactions, perceived operative skills and patient care, and leadership were some of the notable factors when finalizing rank lists.

CONCLUSIONS

A multitude of factors define a successful matriculant, including quality of letters of recommendation, quality and quantity of publications, supportive phone calls, observed interactions, interview performance, perceptions of being team player with leadership skills as well as perceptions of good operative skills and patient care.

LEVEL OF EVIDENCE

Type II.

TYPE OF STUDY

Prognostic (retrospective).

Putting patients at the center of kidney care transitions: PREPARE NOW, a cluster randomized controlled trial

Care for patients transitioning from chronic kidney disease to kidney failure often falls short of meeting patients' needs. The PREPARE NOW study is a cluster randomized controlled trial studying the effectiveness of a pragmatic health system intervention, 'Patient Centered Kidney Transition Care,' a multi-component health system intervention designed to improve patients' preparation for kidney failure treatment. Patient-Centered Kidney Transition Care provides a suite of new electronic health information tools (including a disease registry and risk prediction tools) to help providers recognize patients in need of Kidney Transitions Care and focus their attention on patients' values and treatment preferences. Patient-Centered Kidney Transition Care also adds a 'Kidney Transitions Specialist' to the nephrology health care team to facilitate patients' self-management empowerment, shared-decision making, psychosocial support, care navigation, and health care team communication. The PREPARE NOW study is conducted among eight [8] outpatient nephrology clinics at Geisinger, a large integrated health system in rural Pennsylvania. Four randomly selected nephrology clinics employ the Patient Centered Kidney Transitions Care intervention while four clinics employ usual nephrology care. To assess intervention effectiveness, patient reported, biomedical, and health system outcomes are collected annually over a period of 36 months via telephone questionnaires and electronic health records. The PREPARE NOW Study may provide needed evidence on the effectiveness of patient-centered health system interventions to improve nephrology patients' experiences, capabilities, and clinical outcomes, and it will guide the implementation of similar interventions elsewhere.

TRIAL REGISTRATION

NCT02722382.

Intestinal Hypoganglionosis Leading to Intestinal Failure and the Compassionate Use of Omegaven™

Intestinal hypoganglionosis is a rare innervation disorder that provides numerous nutritional, medical and surgical challenges. In this case report, we present a case of a newborn with intestinal hypoganglionosis leading to intestinal failure and intestinal failure-associated liver disease who responded to Omegaven™, a fat emulsion comprised of omega-3 fatty acids. Omegaven™ has been shown to be beneficial in the management of cholestatic liver injury. Clinical success with Omegaven™ was seen in this patient with a clear decrease in aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and complete resolution of cholestasis with a direct bilirubin of zero within two weeks of initiation of Omegaven™. No current guidelines for the diagnosis and management of hypoganglionosis are available. We recommend a multidisciplinary approach and the use of novel therapies such as fat emulsions composed of omega-3 fatty acids for improved patient outcomes. Appropriate compassionate use protocols should be obtained from the Food and Drug Administration prior to initiation of Omegaven™.

Alpha-2 adrenergic stimulation triggers Achilles tenocyte hypercellularity: Comparison between two model systems

The histopathology of tendons with painful tendinopathy is often tendinosis, a fibrosis-like condition of unclear pathogenesis characterized by tissue changes including hypercellularity. The primary tendon cells (tenocytes) have been shown to express adrenoreceptors (mainly alpha-2A) as well as markers of catecholamine production, particularly in tendinosis. It is known that adrenergic stimulation can induce proliferation in other cells. The present study investigated the effects of an exogenously administered alpha-2 adrenergic agonist in an established in vivo Achilles tendinosis model (rabbit) and also in an in vitro human tendon cell culture model. The catecholamine producing enzyme tyrosine hydroxylase and the alpha-2A-adrenoreceptor (α_2A AR) were expressed by tenocytes, and alpha-2 adrenergic stimulation had a proliferative effect on these cells, in both models. The proliferation was inhibited by administration of an α_2A AR antagonist, and the in vitro model further showed that the proliferative alpha-2A effect was mediated via a mitogenic cell signaling pathway involving phosphorylation of extracellular-signal-regulated kinases 1 and 2. The results indicate that catecholamines produced by tenocytes in tendinosis might contribute to the proliferative nature of the pathology through stimulation of the α_2A AR, pointing to a novel target for future therapies. The study furthermore shows that animal models are not necessarily required for all aspects of this research.

Mechanical force modulates scleraxis expression in bioartificial tendons

Following tendon injury, cartilage, bone and fat metaplasia are often observed, making the optimization of tenocyte differentiation an important clinical goal. In this study we examined the effect of static and cyclic mechanical loading on the expression of genes which play a role in tenocyte differentiation and function, namely scleraxis (Scx) and Type I collagen (Col1a1), and determined the effect of varying mechanical parameters including (1) static vs dynamic load, (2) increasing strain magnitude, (3) inclusion of 10 s rest periods, and (4) increasing cycle number. Cyclic loading resulted in a greater increase of tenocyte gene expression than static loading over 3 weeks in culture. Increasing strain levels potentiated the induction of tenocyte genes. The insertion of a 10 s rest periods further enhanced tenocyte gene expression, as did increasing repetition numbers. These results suggest that mechanical signaling exerts an important influence on the expression of genes which play a role in determining the tendon phenotype. Further work is required to confirm and extend these findings in primary cells such as resident tendon progenitor/stem cells, in order to provide an improved understanding of biology from which optimized rehabilitation programs can be developed.

Endogenous substance P production in the Achilles tendon increases with loading in an in vivo model of tendinopathy-peptidergic elevation preceding tendinosis-like tissue changes

OBJECTIVES

To quantify the intratendinous levels of substance P (SP) at different stages of overload in an established model for Achilles tendinopathy (rabbit). Also, to study the distribution of the SP-receptor, the NK-1R, and the source of SP, in the tendon.

METHODS

Animals were subjected to the overuse protocol for 1, 3 or 6 weeks. One additional group served as unexercised controls. Immunoassay (EIA), immunohistochemistry (IHC), and in situ hybridisation (ISH) were performed.

RESULTS

EIA revealed increased SP-levels in the Achilles tendon of the exercised limb in all the experimental groups as compared to in the controls (statistically significant; p=0.01). A similar trend in the unexercised Achilles tendon was observed but was not statistically significant (p=0.14). IHC and in ISH illustrated reactions of both SP and NK-1R mainly in blood vessel walls, but the receptor was also found on tenocytes.

CONCLUSIONS

Achilles tendon SP-levels are elevated already after 1 week of loading. This shows that increased SP-production precedes tendinosis, as tendinosis-like changes occur only after a minimum of 3 weeks of exercise, as shown in a recent study using this model. We propose that central neuronal mechanism may be involved as similar trends were observed in the contralateral Achilles tendon.

Self-expanding silicone stent for treatment of postoperative colorectal stricture in an infant with Hirschsprung's disease: a case report

Benign colorectal strictures can be a complication of intestinal surgery, with limited options for endoscopic intervention. In this report, we describe a case where a removable silicone stent was temporarily placed to successfully treat a benign post operative stricture in an infant with Hirschsprung's disease.

In the african lungfish Met-enkephalin and leu-enkephalin are derived from separate genes: cloning of a proenkephalin cDNA

A full-length proenkephalin cDNA (accession number: AF232670) was cloned from an African lungfish (Protopterus annectens) brain cDNA library. The 1,351-bp African lungfish proenkephalin contains an open reading frame that codes 266 amino acids and a stop codon. Within the sequence of lungfish proenkephalin there are 5 pentapeptide opioid sequences (all YGGFM), 1 octapeptide opioid sequence (YGGFMRSL) and 1 heptapeptide opioid sequence (YGGFMGY). A Leu-enkephalin sequence was conspicuously absent in lungfish proenkephalin. These results, coupled with observations on the organization of amphibian proenkephalin and mammalian proenkephalin, indicate that among the Sarcopterygii (lobed finned fish and tetrapods), the appearance of a Leu-enkephalin sequence in proenkephalin may have evolved in either the ancestral amniotes or the ancestral mammals, but not earlier in sarcopterygian evolution. Furthermore, the detection of neurons in the lungfish CNS that are only immunopositive for Met-enkephalin, coupled with earlier anatomical studies on the presence of neurons in the lungfish CNS that are only immunopositive for Leu-enkephalin, indicates that a Leu-enkephalin-coding opioid gene must be present in the CNS of the lungfish. This gene may be the lungfish form of prodynorphin. Given the phylogenetic position of the lungfish in vertebrate evolution, the putative Leu-enkephalin-coding gene must have evolved in the ancestral sarcopterygian vertebrates, or in the ancestral gnathostomes. The apparent slow rate of lungfish evolution makes these organisms interesting models for investigating the evolution of the opioid/orphanin gene family.

Deciphering the origin of Met-enkephalin and Leu-enkephalin in Lobe-finned fish: cloning of australian lungfish proenkephalin

The previous detection of Met-enkephalin and Leu-enkephalin in the CNS of the Australian lungfish, Neoceratodus forsteri, in a molar ratio comparable to mammals suggested that the lungfish proenkephalin precursor should contain the sequences of both Met-enkephalin and Leu-enkephalin as seen for mammalian proenkephalin. However, the cloning of a full-length proenkephalin cDNA from the CNS of the Australian lungfish indicates that the organization of this precursor is more similar to amphibian proenkephalin than mammalian proenkephalin. The Australian lungfish cDNA is 1284 nucleotides in length and the open reading frame (267 amino acids) contains seven opioid sequences (GenBank #AF232671). There are five copies of the Met-enkephalin sequence flanked by sets of paired basic amino acid proteolytic cleavage sites and two C-terminally extended forms of Met-enkephalin: YGGFMRSL and YGGFMGY. As seen for amphibians, no Leu-enkephalin sequence was detected in the Australian lungfish proenkephalin cDNA. The fact that Leu-enkephalin has been identified by radioimmunoassay and HPLC analysis in the CNS of the Australian lungfish indicates that a Leu-enkephalin-coding gene, distinct from proenkephalin, must be expressed in lungfish. Potential candidates may include a prodynorphin- or other opioid-like gene. Furthermore, the absence of a Leu-enkephalin sequence in lungfish and amphibian proenkephalin would suggest that the mutations that yielded this opioid sequence in tetrapod proenkephalin occurred at some point in the radiation of the amniote vertebrates.

Organization of proenkephalin in amphibians: cloning of a proenkephalin cDNA from the brain of the anuran amphibian, Spea multiplicatus

Cloning of a proenkephalin cDNA from the pelobatid anuran amphibian, Spea multiplicatus, provides additional evidence that Leu-enkephalin, although present in the brain of anuran amphibians, is not encoded by the proenkephalin gene. The S. multiplicatus proenkephalin cDNA is 1375 nucleotides in length, and the open reading frame contains the sequences of seven opioid sequences. There are five copies of the Met-enkephalin sequence, as well as an octapeptide opioid sequence (YGGFMRNY) and a heptapeptide opioid sequence (YGGFMRF). In the proenkephalin sequence of S. multiplicatus the penultimate opioid is a Met-enkephalin sequence rather than the Leu-enkephalin present in mammalian sequences. The same order of opioid sequences also is observed for the proenkephalin sequence of the pipid anuran amphibian, Xenopus laevis. Hence, from a phylogenetic standpoint the organization of tetrapod proenkephalin has been remarkably conserved. What remains to be resolved is whether the Leu-enkephalin sequence found in mammalian proenkephalin is an ancestral trait or a derived trait for the tetrapods. Unlike the proenkephalin precursor of X. laevis, all of the opioid sequences in the S. multiplicatus proenkephalin cDNA are flanked by paired-basic amino acid proteolytic cleavage sites. In this regard the proenkephalin sequence for S. multiplicatus is more similar to mammalian proenkephalins than the proenkephalin sequence of X. laevis. However, a comparison of the proenkephalin sequences in human, X. laevis, and S. multiplicatus revealed several conserved features in the evolution of the tetrapod proenkephalin gene. By contrast, a comparison of tetrapod proenkephalin sequences with the partial sequence of a sturgeon proenkephalin cDNA indicates that the position occupied by the penultimate opioid sequence in vertebrate proenkephalins may be a highly variable locus in this gene.

Cloning of a neoteleost (Oreochromis mossambicus) pro-opiomelanocortin (POMC) cDNA reveals a deletion of the gamma-melanotropin region and most of the joining peptide region: implications for POMC processing

A signature feature of tetrapod pro-opiomelanocortin (POMC) is the presence of three melantropin (MSH) coding regions (alpha-MSH, beta-MSH, gamma-MSH). The MSH duplication events occurred early during the radiation of the jawed vertebrates well over 400 million years ago. However, in at least one order of modern bony fish (subdivision Teleostei; order Salmoniformes; i.e. salmon and trout) the gamma-MSH sequence has been deleted from POMC. To determine whether the gamma-MSH deletion has occurred in other teleost orders, a POMC cDNA was cloned from the pituitary of the neoteleost Oreochromis mossambicus (order Perciformes). In O. mossambicus POMC, the deletion is more extensive and includes the gamma-MSH sequence and most of the joining peptide region. Because the salmoniform and perciform teleosts do not share a direct common ancestor, the gamma-MSH deletion event must have occurred early in the evolution of the neoteleost fishes. The post-translational processing of O. mossambicus POMC occurs despite the fact that the proteolytic recognition sequence, (R/K)-Xn-(R/K) where n can be 0, 2, 4, or 6, a common feature in mammalian neuropeptide and polypeptide hormone precursors, is not present at several cleavage sites in O. mossambicus POMC. These observations would indicate that either the prohormone convertases in teleost fish use distinct recognition sequences or vertebrate prohormone convertases are capable of recognizing a greater number of primary sequence motifs around proteolytic cleavage sites.

Cloning of a proopiomelanocortin cDNA from the pituitary of the Australian lungfish, Neoceratodus forsteri: analyzing trends in the organization of this prohormone precursor

The polypeptide hormone precursor, proopiomelanocortin (POMC), was cloned and sequenced from the pituitary of the Australian lungfish, Neoceratodus forsteri, the only surviving species of the oldest extant lineage of lungfish. The Australian lungfish POMC cDNA had an open reading frame that coded for a 255-amino acid precursor. A comparison of POMC sequences from the Australian lungfish and the African lungfish indicated that the deduced amino acid sequences for ACTH, beta-MSH, and beta-endorphin were over 90% identical. Furthermore, within the open reading frames of the two lungfish POMCs, there was 84% identity at the nucleotide level. Although a gamma-MSH-like region was detected in the Australian lungfish POMC cDNA, this sequence contained mutations that have been detected in the gamma-MSH sequences of some ray-finned fish and are not found in the gamma-MSH sequence of the African lungfish or those of tetrapods. In addition, the sequence of beta-endorphin in the two species of lungfish has amino acid motifs that are found in the beta-endorphin sequences of cartilaginous fish and ray-finned fish but not in tetrapods. However, maximum parsimony analysis of the entire POMC open reading indicated that the lungfish POMC sequences form a clade with two amphibian POMC sequences rather than with POMC sequences from ray-finned fish. This result is consistent with the accepted view that the sarcopterygians (lungfishes and tetrapods) are a monophyletic assemblage. Analysis of rates of divergence for various POMC sequences indicate that point mutations are accumulating in the lungfish POMC sequences at a slower rate than in either amphibian or mammalian POMC sequences. The phylogenetic implications of these observations are discussed.

Cloning of proopiomelanocortin from the brain of the african lungfish, Protopterus annectens, and the brain of the western spadefoot toad, Spea multiplicatus

A degenerate primer, specific for the opioid core sequence YGGFM, was used to clone and sequence proopiomelanocortin (POMC) cDNAs from the brain of the African lungfish, Protopterus annectens, and from the brain of the western spadefoot toad, Spea multiplicatus. In addition, the opioid-specific primer was used to clone and sequence a 3'RACE product corresponding to a portion of the open reading frame of S. multiplicatus proenkephalin. For both species, cDNA was made from a single brain and a degenerate opioid-specific primer provided a reliable probe for detecting opioid-related cDNAs. The African lungfish POMC cDNA was 1,168 nucleotides in length, and contained regions that are similar to tetrapod POMCs and fish POMCs. The African lungfish POMC encodes a tetrapod-like gamma-MSH sequence that is flanked by sets of paired basic amino acid proteolytic cleavage sites. The gamma-MSH region in ray-finned fish POMCs either has degenerate cleavage sites or is totally absent in some species. However, the African lungfish gamma-MSH sequence does contain a deletion which has not been observed in tetrapod gamma-MSH sequences. The beta-endorphin region of lungfish POMC has the di-amino acid sequence tryptophan-aspartic acid in the N-terminal region and an additional glutamic acid residue in the C-terminal region of beta-endorphin - features found in fish beta-endorphin, but not tetrapod beta-endorphins. The western spadefoot toad POMC was 1,186 nucleotides in length, and exhibited an organizational scheme typical for tetrapod POMCs. However, the toad POMC did lack a paired basic amino acid proteolytic cleavage site N-terminal to the beta-MSH sequence. Thus, like rat POMC, it is doubtful that beta-MSH is an end product in either the toad brain or intermediate pituitary. At the amino acid level, the toad POMC had 76% sequence identity with Xenopus laevis POMC and 68% sequence identity with Rana ribidunda POMC. The use of these POMC sequences to assess phylogenetic relationships within anuran amphibians will be discussed. With respect to the fragment of S. multiplicatus proenkephalin cDNA, two metenkephalin sequences and the metenkephalin-RF sequence were found encoded in this fragment. As seen for X. laevis and R. ridibunda proenkephalin, a leuenkephalin sequence was not detected in the C-terminal region of the S. multiplicatus proenkephalin. The absence of a leuenkephalin sequence may be a common feature of anuran amphibian proenkephalins.

Cloning of a second proopiomelanocortin cDNA from the pituitary of the sturgeon, Acipenser transmontanus

A recent study on the pituitary of the sturgeon, Acipenser transmontanus, resulted in the cloning of a cDNA that codes for the prohormone, proopiomelanocortin (POMC). This cDNA is designated sturgeon POMC A. Subsequent analysis of the sturgeon pituitary uncovered a second distinct POMC cDNA (sturgeon POMC B). In both sturgeon POMC cDNAs the open reading frame is 795 nucleotides in length. However, the two sturgeon POMC cDNAs differ at 26 amino acid positions in the opening frame. In addition, the 2 forms of POMC differ at 45 nucleotide positions within the open reading frame. The number and types of point mutations are compared in the 2 sturgeons POMC cDNAs, and the origin of the two POMC genes is discussed.

Deciphering posttranslational processing events in the pituitary of a neopterygian fish: cloning of a gar proopiomelanocortin cDNA

A cDNA that codes for the polypeptide hormone precursor proopiomelanocortin (POMC) was cloned and sequenced from a gar (Lepisosteus osseus) pituitary cDNA library. The gar POMC cDNA is 1237 bp and contains a 780-bp open reading frame. The deduced amino acid sequence for gar POMC is 259 amino acids in length. The general organization of gar POMC is very similar to that of other gnathostome POMC sequences. The beta-endorphin sequence had 91% sequence identity with sockeye A beta-endorphin and 71% sequence identity with Xenopus laevis beta-endorphin. Three melanocyte-stimulating hormone (MSH) core sequences [HFR(W)] were detected. The gar alpha-MSH sequence was identical to the alpha-MSH sequence in rat POMC. The gar beta-MSH sequence had 77% sequence identity with salmonid forms of beta-MSH and 53% sequence identity with tetrapod forms of beta-MSH. The gamma-MSH region of gar POMC only had 26% primary sequence identity with tetrapod gamma-MSH sequences. Gar gamma-MSH had an incomplete MSH core sequence (HRF), an apparent internal deletion of five amino acids, and lacked flanking paired basic amino acids essential for proteolytic cleavage. The apparent degenerate nature of gar gamma-MSH is discussed in light of the absence of this sequence in salmonid fish.

Nucleotide sequence and cellular distribution of rat chromogranin B (secretogranin I) mRNA in the neuroendocrine system

The mRNA of rat secretory-vesicle protein chromogranin B is abundant in brain, adrenal medulla, and anterior pituitary. The primary translation product predicted from the cDNA sequence of this 2,337-nucleotide transcript corresponds to a hydrophilic 655-residue protein preceded by a signal peptide. Both termini of the mature 75-kD protein show extensive similarity to other chromogranins; the more variable internal region is characterized by glutamic acid clusters and numerous pairs of basic residues. In rodent brain, mRNA accumulation starts around embryonic days 13-14 and peaks by postnatal day 20. In situ hybridization in brain sections shows that the mRNA is enriched in the hippocampal formation, the endocrine hypothalamus, the olfactory system, and in anatomically distinct structures in the pons-medulla.

Expression of small cytoplasmic transcripts of the rat identifier element in vivo and in cultured cells

We examined the level of expression of small RNA transcripts hybridizing to a rodent repetitive DNA element, the identifier (ID) sequence, in a variety of cell types in vivo and in cultured mammalian cells. A 160-nucleotide (160n) cytoplasmic poly(A)+ RNA (BC1) appeared in late embryonic and early postnatal rat brain development, was enriched in the cerebral cortex, and appeared to be restricted to neural tissue and the anterior pituitary gland. A 110n RNA (BC2) was specifically enriched in brain, especially the postnatal cortex, but was detectable at low levels in peripheral tissues. A third, related 75n poly(A)- RNA (T3) was found in rat brain and at lower levels in peripheral tissues but was very abundant in the testes. The BC RNAs were found in a variety of rat cell lines, and their level of expression was dependent upon cell culture conditions. A rat ID probe detected BC-like RNAs in mouse brain but not liver and detected a 200n RNA in monkey brain but not liver at lower hybridization stringencies. These RNAs were expressed by mouse and primate cell lines. Thus, tissue-specific expression of small ID-sequence-related transcripts is conserved among mammals, but the tight regulation found in vivo is lost by cells in culture.

Rat and mouse identifier sequences are preferentially but not exclusively located in cortical neuronal genes expressed postnatally

A genetic element called the identifier (ID) sequence, highly repeated in the rat genome, has previously been reported to be located in the introns of some genes transcribed in the adult rat brain by RNA polymerase II (Pol II). We show that nuclear RNA isolated from neurons of cerebral hemispheres (cortex) of 14-day old rats is enriched more than 10-fold in ID sequences compared to nuclear RNA from liver, kidney, cerebellum, or cortical glia. The developmental onset of the difference is during the first 2 weeks after birth. Mouse cortical neuronal nuclear RNA is similarly enriched in an element related but not identical to the rat ID element, and the enrichment also has postnatal onset. The enriched appearance of ID sequences in transcripts whose expression is increased postnatally in cortical neurons correlates developmentally and spatially with the transcription of ID elements by RNA polymerase III (Pol III) and with a change in chromatin structure.

Transcriptional activation of the mouse Mx gene by type I interferon

Mouse cells of the Mx+ genotype accumulate Mx mRNA in response to type I interferon (IFN). Nuclear runoff experiments show that IFN stringently regulates Mx gene expression at the level of transcription. Mx mRNA synthesis peaks about 3 h after IFN treatment, and within 5 h, Mx mRNA concentration rises from undetectable levels to about 0.1% of polyadenylated RNA.

Structural characterization of a heterogeneous family of rat brain mRNAs

A large heterogeneous family of RNAs derived from a single rat gene contains members that differ from each other at one or more of three positions. Their 5' ends are nested and transcription can begin at 22 or more sites covering 265 nucleotides. Many of the 5' ends are detectable only in brain RNAs, and even 5' ends common with other tissues appear with different absolute and relative abundances in brain RNA. The central portions of the RNAs are of two forms, differing only by the presence or absence of 17 nucleotides; these forms are probably produced by alternative splicing. Polyadenylation occurs at either of two sites. This complicated family of 88 RNAs encodes two novel putative proteins that differ at their C termini.

Neuron-specific enolase: complete structure of rat mRNA, multiple transcriptional start sites, and evidence suggesting post-transcriptional control

The protein encoded by a randomly selected rat brain cDNA clone was identified as neuron-specific enolase (NSE; 4.2.1.11; gamma subunit), based on homology to yeast enolase sequences and the presence of the corresponding 2.5-kb mRNA in rat brain but not in liver, kidney, or muscle tissue. The 2,222-nucleotide NSE and mRNA sequence presented identifies a 68-nucleotide 5' noncoding region, a 1,302-nucleotide open reading frame (corresponding to a primary translation product of 434 amino acids), and 852 noncoding 3' bases. Evolutionary implications based on sequence comparisons to yeast enolase and non-neuronal enolase are discussed. Primer extension analysis indicated the presence of several alternative initiation sites for transcription within 60 nucleotides on the NSE gene. The developmental onset of NSE mRNA expression correlates with the appearance of NSE protein; however, the mRNA reaches adult levels by postnatal week 3, whereas the protein continues to accumulate over the next few months, suggesting regulatory mechanisms in addition to transcriptional control.

Lymphangioma of the tongue: medical and surgical therapy

Therapy for lingual lymphangioma consists of the following: --medical therapy for acute swelling in the form of steroids, enzymes, and antibiotics; --surgery by horizontal, partial wedge resection of diffuse lesions, and total excision of small circumscribed lesions; --adjunctive therapy, which includes reduction of sharp incisal edges, early orthondontic therapy for open bite, and orthognathic surgery, if indicated.

Erysipelas: facial lymphangitis

Two cases of facial lymphangitis have been described, and the pathophysiology of erysipelas has been discussed. Now rarely observed by hospital residents, this potentially serious infection can create considerable diagnostic confusion in medical as well as dental services. Rapid response of erysipelas to penicillin therapy is the modern expectation.