Hand injuries in low- and middle-income countries: systematic review of existing literature and call for greater attention.

OBJECTIVES: Hand injuries result in major healthcare costs from lack of productivity and disability. With rapid industrialization, the incidence of hand injuries is expected to rise in low- and middle-income countries (LMICs). However, estimates of burden and validated outcome tools are needed for effective resource allocation in the management of these injuries. STUDY DESIGN: We conducted a systematic review to evaluate the burden of hand injuries in LMICs according to Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. METHODS: We searched PubMed, Scopus, Embase, Cochrane Library, PAIS International, African Index Medicus, Global Health, IMMEMR, IMSEAR, Wholis and Bdenf, Lilacs, Scielo, WPRIM, and WHO International Clinical Trials Registry Platform to detect eligible articles with no restrictions on length of follow-up, type of hand injury, or date. RESULTS: We included 17 articles after screening 933 eligible articles based on title, abstract, and full-text screening. There was significant heterogeneity and low quality of evidence. All included articles suggest that hand injuries were associated with work limitations for the majority of patients, and residual pain can further limit their activities. Direct and indirect costs related to treatment account for a major healthcare burden with limited evidence on estimates of long-term cost from disability. CONCLUSIONS: The present systematic review highlights the paucity of high-quality data on the epidemiology, management, and burden of hand injuries in LMICs. The data are heterogeneous, and comprehensive metrics are lacking. Because hand injuries can account for a significant proportion of injury-related disability, reducing the overall burden of hand injuries is of utmost importance.

Developmental expression of sarcomeric and ubiquitous mitochondrial creatine kinase is tissue-specific.

Creatine kinase (CK) isoenzymes play prominent roles in myocardial energy metabolism. Two nuclear genes encode mitochondrial creatine kinase (MtCK), are tissue-specific in their expression, and are thus designated as sarcomeric MtCK (sMtCK) and ubiquitous MtCK (uMtCK). Quantitative analysis of the mRNA expression of both MtCKs in developing rat tissues demonstrates tissue-specific developmental regulation. sMtCK mRNA in heart is undetectable prenatally but is dramatically upregulated by 28 d postnatally. sMtCK mRNA in skeletal muscle is also extremely low prenatally but is markedly upregulated at birth and doubles by 28 d postnatally. uMtCK mRNA expression is present at low levels in fetal brain and intestine. Brain uMtCK mRNA continues to rise from -4 d prenatally until 28 d postnatally (6-fold increase), but intestinal uMtCK mRNA increases immediately prior to birth, falls, and is upregulated again at 28 d (20-fold). uMtCK mRNA is undetectable in fetal skeletal muscle or heart, but increases to low levels in skeletal muscle at birth and remains at this level into adulthood. uMtCK is not detectable in heart, lung, testes, or liver at any stage examined. We conclude that sMtCK and uMtCK are developmentally regulated in a tissue-specific manner. Unlike cytosolic muscle CK and brain CK, there is no isoenzyme switch between sMtCK and uMtCK in the developing animal. Our results suggest that specific trans-acting factors regulate the different developmental and tissue-specific expression of the MtCK genes.

Structural characterization and tissue-specific expression of the mRNAs encoding isoenzymes from two rat mitochondrial creatine kinase genes.

Creatine kinase (CK; EC 2.7.3.2) isoenzymes play prominent roles in energy transduction. Mitochondrial CK (MtCK) reversibly catalyzes the transfer of high energy phosphate to creatine and exists, in the human, as two isoenzymes encoded by separate genes. We report here the cDNA sequences of the two isoenzymes of MtCK in the rat. Rat sarcomeric MtCK has 87% nucleotide identity in the 1257 bp coding region and 82% in the 154 bp 3' untranslated region as compared with human sarcomeric MtCK. Rat ubiquitous MtCK has 92% nucleotide identity over the 1254 bp coding region with human ubiquitous MtCK and 81% identity of the 148 by 3' untranslated region. Nucleotide identity between the rat sarcomeric and ubiquitous MtCK coding regions is 70%, with no conservation of their 3' untranslated regions. Thus, MtCK sequence is conserved in a tissue-specific, rather than species-specific, manner. Conservation of the 3' untranslated regions is highly unusual and suggests a regulatory function for this region. The NH2-terminal transit peptide sequences share 82% amino acid homology between rat and human sarcomeric MtCKs and 92% homology between rat and human ubiquitous MtCKs, but have only 41% homology to each other. This tissue-specific conservation of the transit peptides suggests receptor specificity in mitochondrial uptake. Rat sarcomeric MtCK mRNA is expressed only in skeletal muscle and heart, but rat ubiquitous MtCK mRNA is expressed in many tissues, with highest levels in brain, gut and kidney. Ubiquitous MtCK mRNA levels are dramatically regulated in uterus and placenta during pregnancy. Coexpression of sarcomeric and ubiquitous MtCK with their cytosolic counterparts, MCK and BCK, respectively, supports the creatine phosphate shuttle hypothesis and suggests that expression of these genes is coordinately regulated.

Mitochondrial trifunctional protein defects: molecular basis and novel therapeutic approaches.

Mitochondrial trifunctional protein (MTP) is a complex protein that catalyzes the last three steps of long chain fatty acid oxidation. MTP defects have emerged recently as important inborn errors of metabolism because of their clinical implications. These disorders are recessively inherited and display a spectrum of clinical phenotypes in affected children including hepatic dysfunction, cardiomyopathy, neuro-myopathy, and may cause sudden unexpected infant death if undiagnosed and untreated. Interestingly, mothers who carry fetuses with MTP defects develop life-threatening complications during pregnancy. Recently, we delineated disease-causing mutations in MTP and reported the molecular basis for the pediatric and fetal-maternal genotype-phenotype correlations. Current management of patients with MTP defects include long-term dietary therapy of fasting avoidance, low fat diet with the restriction of long chain fatty acid intake and substitution with medium chain fatty acids. The long-term outcome of patients treated by dietary modifications remains unknown. Thus, treatment that aims at correcting the metabolic defect remains the therapy of choice for this disorder. Currently, we are exploring the potential use of protein transfection domains (PTD) for treatment of these disorders. We have shown that the transactivator of transcription (TAT) peptide from the human immunodeficiency virus can deliver proteins to mitochondria. We have further developed methods to localize these proteins to mitochondria by including a mitochondrial targeting in the fusion protein construct. Finally, we have shown that the fusion protein can cross the placenta and was detectable in the fetus and newborn pups. The practical therapeutic implications of this novel approach will be discussed.

Frontonasal malformation with tetralogy of Fallot associated with a submicroscopic deletion of 22q11.

We report on a 14-month-old girl with bifid nasal tip and tetralogy of Fallot. Several similar patients have been described with CNS or eye abnormalities. Chromosome analysis with FISH, using Oncor DiGeorge probes, confirmed a submicroscopic deletion of 22q11. Many patients with Shprintzen (velo-cardio-facial) syndrome have a similar deletion with conotruncal cardiac defects and an abnormal nasal shape, suggesting that a gene in this area, possibly affecting neural crest cells, influences facial and other midline development.

Coccidioidal pericarditis.

A 26-year-old man developed coccidioidomycosis which resulted in myocarditis associated with congestive heart failure. A pericardial effusion developed and progressed to constrictive pericarditis. A pericardiectomy was performed and revealed that the pericarditis was due to Coccidioides immitis. The patient was subsequently treated with amphotericin B and showed marked improvement.

Division of venous collateral after Glenn shunt by minimally invasive surgery.

An infant with cyanotic heart disease that was palliated with a bidirectional cavopulmonary shunt developed progressive cyanosis 3 months after the surgical procedure. A large hemizygous vein was found to be decompressing the bidirectional Glenn shunt from the left innominate vein and was ligated using video-assisted thoracoscopic surgery. The unusually rapid appearance of the shunt, and the excellent outcome associated with the video-assisted thoracoscopic surgery procedure are discussed.

Regulation of creatine kinase isoenzymes in human placenta during early, mid-, and late gestation.

OBJECTIVE: Creatine kinase (CK) isoenzymes play an important role in cellular energy transduction. Two isoenzymes of creatine kinase, ubiquitous mitochondrial creatine kinase (uMtCK) and cytosolic brain creatine kinase (BCK), are postulated to form the creatine phosphate (CP) shuttle, in which creatine serves to transport high-energy phosphate from the mitochondria to its site of utilization. Coordinate regulation of these genes is essential for efficient energy transduction. We examined human CK isoenzyme regulation in placentas during all three trimesters of gestation to define the mRNA and protein expression patterns of uMtCK and BCK and to test the CP shuttle hypothesis. METHODS: Placental samples were collected from a total of 26 patients from the first, second, and third trimesters. Total RNA and protein were prepared from each sample and quantified. Quantitative RNA analysis was performed by gel electrophoresis and dot blot techniques using isoenzyme-specific human cDNA probes for uMtCK and BCK. Protein expression of uMtCK and BCK was examined by Western blot analysis using isoenzyme-specific antibodies to uMtCK and BCK. RESULTS: Analysis of RNA demonstrated the coordinate expression of uMtCK and BCK mRNAs in human placenta, with peak expression of both in the term placentas. Western blot analysis demonstrated coordinate expression of uMtCK and BCK proteins in the first and second trimesters, but not in the term placenta. Expression levels of uMtCK and BCK proteins were not consistent with their respective mRNA levels in the term placenta. CONCLUSION: Expression of uMtCK and BCK in human placenta is highly regulated, and post-transcriptional regulation of uMtCK and BCK expression occurs in the term placenta. The coordinate regulation of uMtCK and BCK in human placenta supports the CP shuttle hypothesis. This analysis demonstrates that human placenta has high energy needs that can change rapidly; thus, a functioning CP shuttle may be important in the maintenance and termination of pregnancy.

Expression of engineered human 17 beta-estradiol dehydrogenase in a prokaryotic system.

OBJECTIVE: 17 beta estradiol dehydrogenase (17 beta DH) is a model for pyridine-dependent steroid-converting enzymes. To define the structural and functional parameters of 17 beta DH, we created an expression system for production of abundant, homogeneous enzyme. METHODS: A full-length 17 beta DH cDNA clone was engineered into the inducible expression vector pMON 5839. After induction of plasmid-bearing Escherichia coli JM109 cells, the authenticity of the recombinant human placental 17 beta DH (r17 beta DH) was evaluated. RESULTS: Protein electrophoresis and Western blot analysis confirmed the immunologic identity of r17 beta DH with native human placental enzyme. The amino acid sequence, enzyme activity, Vmax, K(m), and kcat of r17 beta DH matched that of the native enzyme. CONCLUSION: Prokaryotic cell lines offer the opportunity to create an unlimited supply of recombinant human placental 17 beta DH without the expense and time commitment of baculoviral or eukaryotic cell lines. We are now able to use r17 beta DH and its mutants to elucidate the mechanisms of action of this class of enzyme.

Expression of the mitochondrial creatine kinase genes.

Mitochondrial Creatine Kinase (MtCK) is responsible for the transfer of high energy phosphate from mitochondria to the cytosolic carrier, creatine, and exists in mammals as two isoenzymes encoded by separate genes. In rats and humans, sarcomere-specific MtCK (sMtCK) is expressed only in skeletal and heart muscle, and has 87% nucleotide identity across the 1257 bp coding region. The ubiquitous isoenzyme of MtCK (uMtCK) is expressed in many tissues with highest levels in brain, gut, and kidney, and has 92% nucleotide identity between the 1254 bp coding regions of rat and human. Both genes are highly regulated developmentally in a tissue-specific manner. There is virtually no expression of sMtCK mRNA prior to birth. Unlike cytosolic muscle CK (MCK) and brain CK (BCK), there is no developmental isoenzyme switch between the MtCKs. Cell culture models representing the tissue-specific expression of either sMtCK or uMtCK are available, but there are no adequate developmental models to examine their regulation. Several animal models are available to examine the coordinate regulation of the CK gene family and include 1) Cardiac Stress by coarctation (sMtCK, BCK, and MCK), 2) Uterus and placenta during pregnancy (uMtCK and BCK), and 3) Diabetes and mitochondrial myopathy (sMtCK, BCK, and MCK). We report the details of these findings, and discuss the coordinate regulation of the genes necessary for high-energy transduction.

Ribosome binding to mitochondria is regulated by GTP and the transit peptide.

The association between ribosomes and the pore proteins at the endoplasmic reticulum membrane is important to co-translational translocation. To determine if a similar association occurs between the ribosome and mitochondrial membrane protein(s) during protein import in higher eukaryotes, we examined ribosome-mitochondria binding. By using spectral measurements, analysis of mitochondrial associated RNA, and electron microscopy, we demonstrated that ribosomes stably bind to purified rat liver mitochondria in vitro. Binding of ribosomes to mitochondria was markedly reduced by GTP and nearly abolished by the non-hydrolyzable GTP analogue, guanosine-5'-[thio]-triphosphate (GTPgammaS), but was only modestly reduced by GDP or ATP and unaffected by CTP. The initial rate of GTP hydrolysis by mitochondria was increased by ribosomes, whereas the rate of ATP hydrolysis by mitochondria was not affected. Ribosomes programmed with mRNA for 92 amino acids of the N terminus of mitochondrial malate dehydrogenase bound to mitochondria, but unlike unprogrammed rat liver ribosomes, neither GTP nor GDP disrupted binding; however, GTPgammaS did. These data show that receptors specific for ribosomes are present on the mitochondrial membrane, and a GTP-dependent process mediates this binding. The presence of a nascent chain alters these binding characteristics. These findings support the hypothesis that a co-translational translocation pathway exists for import of proteins into mitochondria.

Toward a molecular understanding of congenital heart disease.

BACKGROUND: This review discusses the incidence and importance of congenital heart disease (CHD), the reasons that investigation of causative mechanisms for human CHD has been slow, and the limitations of the multifactorial theory for the etiology of CHD. METHODS AND RESULTS: The molecular defects underlying three vasculopathies--Marfan's syndrome (fibrillin), supravalvar aortic stenosis, and Williams' syndrome (elastin)--and hereditary telangiectasia are presented to emphasize the role of microfibrils and extracellular matrix in the pathophysiology of these vascular defects. Animal models of CHD, including situs inversus, canine conotruncal malformations, and chick neural crest ablation, are examined to emphasize how such studies relate to human CHD, especially by pointing to single-gene defects for conotruncal malformations, candidate loci for situs inversus, and phenotypic variability caused by neural crest lesions. The crucial role of cardiac transcription factors in heart morphogenesis is emphasized by review of gene knockout studies of these factors, which cause fetal death secondary to heart maldevelopment. Several lines of evidence demonstrating genetic etiologies of human CHD are also presented, including the mapping of familial atrial septal defects, to prove that one anatomic type of CHD may be due to single-gene defects at different loci. Review of atrioventricular canal, both secondary to trisomy 21 and as an autosomal-dominant familial defect, reiterates this conclusion. The evidence that monosomy on chromosome 22 causes multiple types of CHD, including aortic arch and conotruncal defects as part of the CATCH-22 syndrome, is presented, with results supporting the idea that deletions at this site alone may cause 5% of surgically treated CHD. CONCLUSIONS: We conclude that (1) human CHD is frequently due to single-gene defects and that even sporadic defects may arise from a single-gene abnormality; (2) a common genetic defect may cause several apparently different forms of CHD; (3) elucidation of the genetic basis of CHD provides clues to normal cardiovascular developmental biology; (4) the same cardiac malformation can be caused by mutant genes at different loci; and (5) interactions of clinical investigators (cardiologists and cardiothoracic surgeons) with basic scientists should allow more rapid progress in defining the genetic basis of CHD.

The genetic basis of paediatric heart disease.

This review focuses on recent advances in understanding the pathogenesis of paediatric heart disease and on the known single gene defects responsible for these diseases. Many paediatric cardiovascular diseases are heritable, have clinical manifestations in adult ages, are frequent in occurrence, and can have significant social and economic impact. Specific gene defects have been identified for hypertrophic and dilated cardiomyopathies, mitochondrial cardiomyopathies, Marfan's syndrome, Williams syndrome, familial supravalvar aortic stenosis, CATCH-22 syndrome and atrioventricular canal. Limited phenotypic response of the developing heart accounts for similar cardiovascular defects from differing gene defects. Although environmental factors affect expression of many of these genes, it is clear that single gene defects can be identified which cause paediatric cardiovascular disease. Interactions among cardiologists, cardiovascular surgeons, geneticists and basic scientists are vitally important in understanding the genetic basis of paediatric heart disease, its diagnosis and its therapy.

Management and follow-up of arterial thrombosis in the neonatal period.

The management and follow-up of 12 patients with major aortic thrombus formation occurring in the neonatal period between 1982 and 1987 are reported. Umbilical arterial catheters were inserted in 8 of the 12 patients before thrombus formation. Two patients had congenital thrombi. Hypertension, oliguria, hematuria, and elevated blood creatinine concentration were found at the time of diagnosis of the thrombus; nine of the patients had a patent ductus arteriosus. Supportive care was instituted in seven patients who were hemodynamically stable. Five of the patients had congestive heart failure, shock, or both, and were treated with surgical thrombectomy. Thrombolytic therapy was not used in either group. The five surgically treated patients and six of seven medically treated patients survived. Ultrasound examination suggested resolution of the thrombus in all survivors in 6 to 30 days. Sequelae from thrombus formation were present in all patients at the time of discharge and included hypertension in 9 of the 11 survivors and decreased renal function in six of them. Follow-up at 1 to 3 years revealed normal blood pressure, good growth, and good renal function in 10 of the survivors.

Post-infarction left ventricular remodeling induces changes in creatine kinase mRNA and protein subunit levels in porcine myocardium.

Energy metabolism is altered in post-infarction remodeled pig myocardium. To understand the basis of this abnormality, we examined the pattern of creatine kinase (CK) gene expression and the relative content of CK protein subunits in pig hearts with proximal left circumflex coronary artery ligation. At 2 months after infarct, both Northern and Western blot analyses were performed on left ventricular myocardium remote from the infarct zone in ligation animals (n = 8). Results were compared with data from the left ventricular myocardium from similar sized normal (control) pigs (n = 7). Steady-state levels of mitochondrial CK mRNA decreased 46% in left ventricular remodeled (LVR) heart samples (93.40 +/- 18.60 arbitrary units) compared with controls (172.85 +/- 37.20 arbitrary units), whereas CK-M subunit mRNA levels remained unchanged between the control and LVR groups (319.50 +/- 35.25 and 352.50 +/- 62.18 arbitrary units, respectively). The mean control group CK-M protein subunits (2.04 +/- 0.31 arbitrary units) decreased 53% (P < 0.05) compared with the LVR group (0.95 +/- 0.25 arbitrary units). Similarly, the mean control group (n = 4) mitochondrial CK protein subunits (1.12 +/- 0.04 arbitrary units) decreased 30% (P < 0.05) compared with the LVR group (n = 4; 0.79 +/- 0.06 arbitrary units). Mean CK-B protein subunits in LVR pig hearts (0.84 +/- 0.23 arbitrary units) increased 77% compared with control (0.48 +/- 0.05 arbitrary units). The total CK activity did not change significantly between control hearts at 164 +/- 11 IU/mg and LVR at 212 +/- 32 IU/mg. We suggest that these alterations of the CK system represent the bioenergetic phenotype of LVR myocardium at the molecular level. The CK system response may ultimately prove inadequate in meeting the abnormal energy requirements of remodeled heart and, therefore, may contribute to the transition toward failure.