Reverse Hemi-Hamate Autograft for Volar Proximal Interphalangeal Joint Fracture-Dislocations.

Volar proximal interphalangeal joint fracture-dislocations are rare injuries. Treatment is challenging when they are not identified acutely, with poor outcomes reported. We report a surgical technique to treat chronic volar proximal interphalangeal joint fracture-dislocations: a reverse hemi-hamate autograft.

The ulnohumeral arthroplasty: technical tips for safely managing the brachial artery.

One surgical option to manage idiopathic osteoarthritis of the elbow is an ulnohumeral arthroplasty. A potential complication to avoid during this procedure is inadvertent over penetration of the anterior cortex of the humerus. If this occurs, injury to the median nerve and brachial artery is possible as these structures may lie within 7 mm of the anterior humerus. This surgical technique describes technical tips in regards to patient positioning and specific instrument usage that serve to diminish the risk of this catastrophic complication occurring by allowing these critical neurovascular structures to fall away from the anterior humerus.

Erythropoietic protoporphyria a clinical and molecular study from Lebanon: Ferrochelatase a potential tumor suppressor gene in colon cancer.

Erythropoietic protoporphyria (EPP) is a rare cutaneous and systemic disease caused by mutations in the ferrochelatase gene (FECH). The molecular underpinnings of EPP in Middle Eastern populations and relative to other ethnic groups secondary to increased consanguinity are unknown. To understand the molecular pathogenesis of Middle Eastern EPP, we surveyed clinicopathological and molecular features in 6 large consanguineous families from Lebanon and Syria presenting with cutaneous and systemic features consistent with EPP. We observed 30% increased liver disease and 20% elevated end-stage liver complications in our EPP cohort compared to EPP patients previously reported elsewhere. In addition, Middle Eastern EPP patients in our cohort exhibited uniquely an increased incidence of colon cancer. Sequence analysis revealed 2 novel non-synonymous FECH mutations in the studied families designated p.M294T and p.I230M. In addition, FECH activity was significantly decreased (6%) in fibroblasts obtained from sun-exposed sites in a patient with p.M294T mutation, whereas in sharp contrast, protected sites from the same patient exhibited 54% activity for the gene. We also found that sun-exposed fibroblasts, relative to sun-protected and control fibroblasts, exhibited suppressed growth and atypical morphology in vitro, and that these effects were alleviated when the cells were co-cultured with sun-protected fibroblasts. Our findings on the increased incidence of colon cancer in EPP patients prompted us to survey FECH expression patterns in cancer. Using publicly available microarray datasets we found that FECH mRNA was largely significantly decreased in colon adenocarcinomas relative to normal colon tissues. Our findings suggest that families with autosomal recessive EPP should be screened more extensively for systemic involvement including liver diseases and colon cancer, and point to a previously unknown yet plausible tumor suppressor role for FECH in colon malignancy.

Ambulatory assistive devices in orthopaedics: uses and modifications.

Ambulatory assistive devices (eg, canes, crutches, walkers) provide advantages such as stability, augmentation of muscle action, and reduction of weight-bearing load. Although they are often prescribed, a detailed understanding of these devices is often lacking, which can lead to detrimental consequences. Comprehension of normal gait cadence, as well as the gait patterns used in both reciprocating and swinging gait, allows the orthopaedic surgeon to understand the limitations of the patient with gait abnormalities. Appreciating the types of assistive devices, their modifications, associated gait patterns, physiologic demand, proper fitting, and indications for use is essential in prescribing the proper device.

Ketoacidosis at presentation of type 1 diabetes in children in Kuwait: frequency and clinical characteristics.

BACKGROUND: Diabetic ketoacidosis (DKA) has significant morbidity and mortality, and is common at diagnosis in children. OBJECTIVE: Describe the frequency and severity of DKA at diagnosis of type 1 diabetes mellitus (T1DM) in children in Kuwait. METHODS: Hospital records of 677 diabetic children less than 12 yr of age, diagnosed during the period of 2000-2006 were reviewed. DKA was defined as blood glucose > 11 mmol/L, pH < 7.3, and/or bicarbonate < 15 mmol/L with ketonuria. RESULTS: Of all patients diagnosed with T1DM, 255 (37.7%) presented with DKA. The frequency of DKA was constant between 2000 and 2002 (42.7-41.5%), but decreased in the following years to 30.7% in 2006 (p < 0.005). The majority had either mild or moderate DKA (74.1%). Fifty-one (36.7%) of all children in the 0-4 yr had severe DKA compared to ten (2.9%) in the 5- to 8-yr-old group, and three (1.5%) in 9- to 12-yr-old patients (p < 0.0001). Moreover, 83% of children with severe DKA were in the 0-4 yr age group. One child (0.15%) died and twenty-seven (4%) needed intensive care unit (ICU) care. CONCLUSION: Our study provides recent data on Middle Eastern population, for whom data are sparse. Although it has significantly decreased, the frequency of DKA at presentation of T1DM in children in Kuwait is still high, secondary to the high prevalence of diabetes in the community. Young children, especially those less than 2 yr old remain at high risk. Increasing the general awareness of the public as well as of pediatricians to the disease may lead to early diagnosis before the development of acidosis.

Molecular cloning and characterization of thyroid hormone receptors in teleost fish.

Thyroid hormones are pleiotropic factors important for many developmental and physiological functions in vertebrates. Their effects are mediated by two specific receptors (TRalpha and TRbeta) which are members of the nuclear hormone receptor superfamily. To clarify the function of these receptors, our laboratory has started a comparative study of their role in teleost fish. This type of approach has been hampered by the isolation of specific clones for each fish species studied. In this report, we describe an efficient reverse transcription/PCR procedure that allows the isolation of large fragments corresponding to TRalpha and TRbeta of a wide range of teleost fish. Phylogenetic analysis of these receptors revealed a placement consistent with their origin, sequences from teleost fish being clearly monophyletic for both TRalpha and TRbeta. Interestingly, this approach allowed us to isolate (from tilapia and salmon) several new TRalpha or TRbeta isoforms resulting from alternative splicing. These isoforms correspond to expressed transcripts and thus may have an important physiological function. In addition, we isolated a cDNA encoding TRbeta in the Atlantic salmon (Salmo salar) encoding a functional thyroid hormone receptor which binds specific thyroid hormone response elements and regulates transcription in response to thyroid hormones.

Candidate gene analysis of thyroid hormone receptors in metamorphosing vs. nonmetamorphosing salamanders.

We used two different experimental approaches to test the hypothesis that thyroid hormone receptor (TR) variation is associated with alternate life cycles modes in ambystomatid salamanders. In the first experiment, the inheritance of TRalpha and TRbeta genotypes was determined for metamorphic and non metamorphic offspring from backcrosses between Ambystoma mexicanum (an obligate metamorphic-failure species) and metamorphic F1 hybrids (A. mexicanum x A. tigrinum tigrinum). The segregation of TR genotype was independent of the expression of life cycle mode phenotype, and neither TR locus was linked to DNA markers that flank a major-effect locus for life cycle mode. In the second experiment, a portion of the ligand-binding domain of TRalpha and TRbeta was cloned and sequenced for DNA samples from 14 different ambystomatid salamander populations, including obligate metamorphic, facultative metamorphic, and obligate metamorphic-failure taxa. Nucleotide sequence variation was found for both TRalpha and TRbeta, with several nonsynonomous substitutions that presumably code for nonconservative amino acid replacements. However, no general relationship was found between TR allelic variation and life cycle mode among populations or species. These data do not implicate TRs as candidate loci involved in the current maintenance or past evolution of alternate life cycle modes in members of the tiger salamander complex.

Ligand binding was acquired during evolution of nuclear receptors.

The nuclear receptor (NR) superfamily comprises, in addition to ligand-activated transcription factors, members for which no ligand has been identified to date. We demonstrate that orphan receptors are randomly distributed in the evolutionary tree and that there is no relationship between the position of a given liganded receptor in the tree and the chemical nature of its ligand. NRs are specific to metazoans, as revealed by a screen of NR-related sequences in early- and non-metazoan organisms. The analysis of the NR gene duplication pattern during the evolution of metazoans shows that the present NR diversity arose from two waves of gene duplications. Strikingly, our results suggest that the ancestral NR was an orphan receptor that acquired ligand-binding ability during subsequent evolution.

Thyroid hormone receptor genes of neotenic amphibians.

Since thyroid hormones play a pivotal role in amphibian metamorphosis we used PCR to amplify DNA fragments corresponding to a portion of the ligand-binding domain of the thyroid hormone receptor (TR) genes in several neotenic amphibians: the obligatory neotenic members of the family Proteidea the mudpuppy Necturus maculosus and Proteus anguinus as well as two members of the facultative neotenic Ambystoma genus: the axolotl Ambystoma mexicanum and the tiger salamander Ambystoma tigrinum. In addition, we looked for TR genes in the genome of an apode Typhlonectes compressicaudus. TR genes were found in all these species including the obligatory neotenic ones. The PCR fragments obtained encompass both the C and E domains and correspond to alpha and beta genes. Their sequences appear to be normal, suggesting that there is no acceleration of evolutionary rates in the TR genes of neotenic amphibians. This result is not surprising for Ambystomatidae, which are known to respond to T3 (3,3',5-triiodothyronine) but is not in agreement with biochemical and biological data showing that Proteidea cannot respond to thyroid hormones. Interestingly, by RT-PCR analysis we observed a high expression levels of TRalpha in gills, intestine, and muscles of Necturus as well as in the liver of Ambystoma mexicanum, whereas TRbeta expression was only detected in Ambystoma mexicanum but not in Necturus. Such a differential expression pattern of TRalpha and TRbeta may explain the neoteny in Proteidea. The cloning of thyroid-hormone-receptor gene fragments from these species will allow the molecular study of their failure to undergo metamorphosis.

Thyroid hormone receptors in perennibranchiate amphibians.

Thyroid hormone has long been known to induce metamorphosis in amphibians. The understanding of the molecular steps controlling the completion of metamorphosis has nevertheless been hampered by the complexity of this event. The comparison of organisms in which metamorphosis does or does not occur, may provide clues into the molecular cascade that control it. Up to now the available data suggest that perennibranchiate amphibians retain their larval characters mainly because their tissues do not respond to thyroid hormones. In such a context the recent identification of a thyroid hormone receptor alpha in the perennibranchiate Proteus anguinus is provocative (Ho Huynh et al., Int. J. Dev. Biol. 40:537-543, 1996). In the present paper, we provide evidences that this recently described sequence is in fact a sequence from Xenopus laevis. Indeed, we identified the authentic thyroid hormone receptors of both alpha and beta types in two perennibranchiate species Necturus maculosus and Proteus anguinus. The various controls required to ascertain the authenticity of a developmental gene cloned by PCR or RT-PCR analysis are presented. The results reported in the present paper are relevant with phylogenetical analysis. This induces our team to conclude that the Proteus TR alpha sequence reported by Ho Huynh et al. (1996) reflects a contamination of the RT-PCR by Xenopus laevis material.