Fetus in Fetu: A Case Report and Review of Literature

Fetus-in-fetu is a rare congenital malformation in which a vertebra fetus is enclosed within the abdomen of a normally developing fetus. The preoperative diagnosis is challenging. Less than 200 cases are reported in English literature, five in Africa. Multiple fetuses-in-fetu are less documented. We report a three month old infant who presented with an abdominal mass and constipation and taken to theatre with a preoperative diagnosis of a teratoma. At operation, the mass was a case of twin fetuses in fetu with blood supply from the aorta and the left renal artery. Total excision of the mass with special attention to its blood supply was therapeutic. We emphasize the necessity for suspicion of fetus in fetu when a well-defined encapsulated cystic mass with calcified solid components is detected by an abdominal CT scan in a child less than 2 years of age. The Annals of African Surgery, Volume 6, 201

Disorders of sexual differentiation as seen at Kenyatta National Hospital

Background: Disorders of sexual differentiation (DSD) are a group of congenital anomalies characterised by discordance between genetic, gonadal and phenotypic sex. There has been remarkable evolution in management over the last decade, including nomenclature, diagnosis and management. There has also been increased awareness and interest from patients and the public, including legal opinion. There has however been no local study to document and evaluate management in Kenya.Objective: To describe management of patients presenting with DSD at Kenyatta National Hospital (KNH) over a 10 year period.Design: Retrospective descriptive study.Setting: Kenyatta National Hospital.Subjects: Patients diagnosed with DSD.Results: A total of 30 patients whose charts were available were reviewed. Age ranged from birth to 19 years (median 5 months) at diagnosis. Presumed gender was assigned at birth in 28 patients. Karyotyping was available in 23(76%) patients. Other common tests included blood tests (23, 76%), ultrasound scan (14, 47%), contrast studies (3, 10%) and exploratory laparoscopy or laparotomy. 46XX and 46XY DSD were the most common conditions encountered (13, 43% and 7, 23% respectively). The commonest operations were correction of hypospadias and orchidopexy (55%), followed by feminising genitoplasty (16%). Only two patients had gender reassignment. Fifteen patients were asked how they feel about their current gender, and 11 expressed satisfaction.Conclusion: DSD is a relatively rare condition. There are also no strict protocols being followed. Management at KNH is acceptable although there is a lack of facilities to carry out many requisite investigations

Production of crystallizable human chymase from a Bacillus subtilis system

AbstractA Bacillus subtilis strain deficient in seven extracellular proteases was used to produce human mast cell chymase and is a viable expression system for serine proteases and other classes of proteins. Chymase is produced at 0.3–0.5 mg/l and is purified by three chromatography steps. Two crystal forms of PMSF-treated chymase were optimized. The first is C2 with a=47.94 Å, b=85.23 Å, c=174.18 Å, β=96.74°, and diffracts to at least 2.1 Å, while the second is P212121, with cell dimensions a=43.93 Å, b=58.16 Å, and c=86.09 Å, and a diffraction limit of approximately 1.9 Å. The first crystal form has either three or four molecules/asymmetric unit, while the second has one molecule/asymmetric unit

Codon reassignment in the Escherichia coli genetic code

Most organisms, from Escherichia coli to humans, use the ‘universal’ genetic code, which have been unchanged or ‘frozen’ for billions of years. It has been argued that codon reassignment causes mistranslation of genetic information, and must be lethal. In this study, we successfully reassigned the UAG triplet from a stop to a sense codon in the E. coli genome, by eliminating the UAG-recognizing release factor, an essential cellular component, from the bacterium. Only a few genetic modifications of E. coli were needed to circumvent the lethality of codon reassignment; erasing all UAG triplets from the genome was unnecessary. Thus, UAG was assigned unambiguously to a natural or non-natural amino acid, according to the specificity of the UAG-decoding tRNA. The result reveals the unexpected flexibility of the genetic code

Continuous symmetry of C60 fullerene and its derivatives

Conventionally, the Ih symmetry of fullerene C60 is accepted which is supported by numerous calculations. However, this conclusion results from the consideration of the molecule electron system, of its odd electrons in particular, in a close-shell approximation without taking the electron spin into account. Passing to the open-shell approximation has lead to both the energy and the symmetry lowering up to Ci. Seemingly contradicting to a high-symmetry pattern of experimental recording, particularly concerning the molecule electronic spectra, the finding is considered in the current paper from the continuous symmetry viewpoint. Exploiting both continuous symmetry measure and continuous symmetry content, was shown that formal Ci symmetry of the molecule is by 99.99% Ih. A similar continuous symmetry analysis of the fullerene monoderivatives gives a reasonable explanation of a large variety of their optical spectra patterns within the framework of the same C1 formal symmetry exhibiting a strong stability of the C60 skeleton.Comment: 11 pages. 5 figures. 6 table

Stops making sense: translational trade-offs and stop codon reassignment

Background Efficient gene expression involves a trade-off between (i) premature termination of protein synthesis; and (ii) readthrough, where the ribosome fails to dissociate at the terminal stop. Sense codons that are similar in sequence to stop codons are more susceptible to nonsense mutation, and are also likely to be more susceptible to transcriptional or translational errors causing premature termination. We therefore expect this trade-off to be influenced by the number of stop codons in the genetic code. Although genetic codes are highly constrained, stop codon number appears to be their most volatile feature. Results In the human genome, codons readily mutable to stops are underrepresented in coding sequences. We construct a simple mathematical model based on the relative likelihoods of premature termination and readthrough. When readthrough occurs, the resultant protein has a tail of amino acid residues incorrectly added to the C-terminus. Our results depend strongly on the number of stop codons in the genetic code. When the code has more stop codons, premature termination is relatively more likely, particularly for longer genes. When the code has fewer stop codons, the length of the tail added by readthrough will, on average, be longer, and thus more deleterious. Comparative analysis of taxa with a range of stop codon numbers suggests that genomes whose code includes more stop codons have shorter coding sequences. Conclusions We suggest that the differing trade-offs presented by alternative genetic codes may result in differences in genome structure. More speculatively, multiple stop codons may mitigate readthrough, counteracting the disadvantage of a higher rate of nonsense mutation. This could help explain the puzzling overrepresentation of stop codons in the canonical genetic code and most variants