Transfer of an ampicillin resistance gene between two Escherichia coli strains in the bowel microbiota of an infant treated with antibiotics

OBJECTIVES: To investigate the presumed acquisition of ampicillin resistance by an Escherichia coli strain residing in the gut of an infant. METHODS: E. coli strains were quantified in faecal samples obtained at regular intervals from an infant followed from birth to 12 months of age and their resistance profiles were determined. beta-Lactamases were identified by isoelectric focusing and genes by PCR followed by DNA sequencing. Plasmids were characterized by restriction fragment analysis and Southern-blot hybridization, and tested for conjugative transfer. RESULTS: The infant carried two E. coli strains, termed 29A and 29B, simultaneously in the microbiota during the first month of life. All isolates of 29A were resistant to ampicillin, whereas strain 29B, which was initially ampicillin susceptible, acquired resistance following treatment of the infant with ampicillin/amoxicillin because of urinary tract infection. Acquisition of resistance by strain 29B was associated with acquisition of a bla(TEM-1b)-encoding plasmid, pNK29, which was also present in strain 29A. Transfer of plasmid pNK29 could be replicated by conjugation from strain 29A to strain 29B in vitro. Strain 29A also adapted to ampicillin treatment by mutation of the bla(TEM-1b) promoter gene to yield a higher level of resistance. CONCLUSIONS: This is an unequivocal demonstration of gene transfer between two strains co-residing in the human gut, as the donor, recipient and transconjugant strains were isolated. The results suggest the dynamic adaptation by commensal bacteria in response to antibiotic treatment may occur readily.     

Cephalic index correlates poorly with intracranial volume in non-syndromic scaphocephalic patients

Objectives

This study aims to compare pre- and postoperative cephalic indexes (CI) with corresponding segmented intracranial volumes (SIV) obtained from volumetric CT in scaphocephalic patients.

Methods

Twenty-four patients (17 boys) who had undergone cranial vault remodeling due to scaphocephaly were compared from 3D-CT imaging datasets. The mean age of the patients at preoperative CT imaging was 5.5 months, and that at 1-year postoperative imaging, 21.5 months. The mean interval between preoperative CT imaging and surgery was 3.3 months. Pearson’s correlation was used to test the correlation of both pre- and postoperative CI with SIV. A paired t test was used to compare differences in the pre- and postoperative mean values of CI and SIV.

Results and discussion

CI correlated poorly with intracranial volume both preoperatively (r?=?0.274) and postoperatively (r?=?0.128). The mean preoperative CI was 65.92 (range 57.99–73.97), and the mean postoperative, CI 70.24 (range 60.23–75.57). The mean preoperative intracranial volume was 877.79 cm³ (range 638–1,256), and the 1-year postoperative volume, 1,249.04 cm³ (range 1,039–1,529). The mean values of both CI and SIV increased significantly after surgery. In one patient, the CI in postoperative measurements was smaller, whereas in all patients, the postoperative SIV was larger than the preoperative intracranial volume. The mean percentage increase in CI was 6.6 %, whereas the mean increase in SIV was 43.1 %.

Conclusion

Cephalic index correlates poorly with intracranial volume in non-syndromic scaphocephalic patients. For some patients, surgery and growth resulted in only subtle or no change in CI despite a notable increase in intracranial volume.     

Twin pregnancy with a fetus in each half of a uterus didelphys.

A rare case of a twin pregnancy with a fetus in each half of a uterus didelphys (double uterus, double cervix and septate vagina) is reported. A longitudinal vaginal septum and two portios were detected during the first labor of this patient. During her second pregnancy ultrasonography was performed in the 16th week, and pregnancy was detected in each half of the double uterus. Both fetuses were of similar size and corresponded to the gestational age. A completely separated double uterus was confirmed by ultrasonography. In the 38th week a female and a male infant were delivered by cesarean section. The follow-up of this pregnancy and the management of the labor are reported.     

Rhabdomyolysis caused by hot air sauna burn

Sauna-related burns are rare, even in Finland where sauna bathing is a popular leisure pastime. Burns induced by hot air are even more rare and constitute a very small subgroup of all sauna burns. Hot air burns are characterised by a combination of full thickness skin damage with deep tissue destruction. We report here on six consecutive patients suffering from hot air sauna burns with rhabdomyolysis. All six patients were middle-aged, the majority of them men. Acute excessive consumption of alcohol exacerbated by a hot environment resulted in dehydration and loss of consciousness. Immobility and prolonged exposure to hot, dry air resulted in third degree regional burns with 5-32% TBSA. Rhabdomyolysis was evident on admission. The laboratory values of plasma creatine kinase (P-CK), plasma myoglobin (PM), blood pH, and serum potassium (S-K) during the first five days were evaluated. Aggressive fluid management and correction of acidosis and myoglobinuria were started on admission. Surgical management consisted of early, aggressive excision at fascial level, in some patients involving sacrifice of the upper layers of muscle. Even so, mortality in this small series was 50%. The best indicator of poor prognosis was a highly elevated CK value on the second post-injury day.     

Analysis of gene and protein expression in healthy and carious tooth pulp with cDNA microarray and two-dimensional gel electrophoresis

Complementary DNA (cDNA) microarray and two-dimensional (2-D) gel electrophoresis, combined with mass spectrometry, enable simultaneous analysis of expression patterns of thousands of genes, but their use in pulp biology has been limited. Here we compared gene and protein expression of pulp tissues from sound and carious human teeth using cDNA microarray and 2-D gel electrophoresis to evaluate their usefulness in pulp biology research and to identify the genes with changes in carious teeth. The cDNA microarray revealed several differentially expressed genes and genes with a high expression in both tissues. These genes have various functions, e.g. effects on vascular and nerve structures, inflammation, and cell differentiation. Variability between cDNA hybridizations indicates that the overall gene expression pattern may vary significantly between individual teeth. The 2-D gel electrophoresis revealed no change between healthy and diseased tissue. The identification of 96 proteins in the pulp tissue revealed none of the gene products with corresponding high/different mRNA expression in cDNA microarray. Interestingly, we detected also a hypothetical protein (putative nucleoside diphosphate kinase), and present therefore the first evidence for the existence of this protein. Even though the methods reveal potentially important gene expression, they may currently have only limited value in in vivo pulp biology research.     

Caspase activation in an experimental model of retinal detachment

PURPOSE: To test for apoptotic photoreceptor cell death and caspase activation as a function of time after induction of an experimental retinal detachment. METHODS: Retinal detachments were created in Brown Norway rats by injecting 10% hyaluronic acid into the subretinal space using a transvitreous approach. Light microscopy and terminal dUTP-biotin nick end-labeling (TUNEL) was performed at 1, 3, 5, and 7 days after detachment to assess for the morphologic features associated with apoptosis. Western blot analysis of retinal protein extracts was performed using antibodies against caspase-3, -7, and -9 and poly-ADP ribose-polymerase (PARP) at 1, 3, and 5 days after detachment. RESULTS: Light microscopic analysis of detached retinas showed the presence of pyknotic nuclei in the outer nuclear layer and disruption of the normal organization of the photoreceptor outer segments. TUNEL-staining was positive in the outer nuclear layer only in the detached portions of the retina. Western blot analysis confirmed the time-dependent activation of caspase-3, -7, and -9 and PARP in the detached retinas. No morphologic stigmata of apoptosis or caspase activation was detected in attached retinas. CONCLUSIONS: The apoptotic photoreceptor cell death in experimental retinal detachments is associated with caspase activation.     

The pharmacokinetics of mifepristone in humans reveal insights into differential mechanisms of antiprogestin action

The pharmacokinetics of mifepristone is characterized by rapid absorption, a long half-life of 25–30 h, and high micromolar serum concentrations following ingestion of doses of ≥100 mg of the drug. The serum transport protein— 1-acid glycoprotein (AAG)—regulates the serum kinetics of mifepristone in man. Binding to AAG limits the tissue availability of mifepristone, explaining its low volume of distribution and low metabolic clearance rate of 0.55 L/kg per day. In addition, the similar serum levels of mifepristone following ingestion of single doses exceeding 100 mg can be explained by saturation of the binding capacity of serum AAG. Mifepristone is extensively metabolized by demethylation and hydroxylation, the initial metabolic steps being catalyzed by the cytochrome P-450 enzyme CYP3A4. The three most proximal metabolites, namely, monodemethylated, didemethylated and hydroxylated metabolites of mifepristone, all retain considerable affinity toward human progesterone and glucocorticoid receptors. Also, the serum levels of these three metabolites are in ranges similar to those of the parent mifepristone. Thus, the combined pool of mifepristone—plus its metabolites—seems to be responsible for the biological actions of mifepristone. Recent clinical studies on pregnancy termination and emergency contraception have focused on optimization of the dose of mifepristone. In these studies it has become apparent that the doses efficient for pregnancy termination differ from those needed in emergency contraception—mifepristone is effective in emergency contraception at a dose of 10 mg, which results in linear pharmacokinetics. However, the ≥200 mg doses of mifepristone needed for optimal abortifacient effects of mifepristone result in saturation of serum AAG and thus nonlinear pharmacokinetics. In view of the pharmacokinetic data, it may be speculated that dosing of mifepristone for pregnancy termination and for emergency contraception could be reduced to approximately 100 mg and 2–5 mg, respectively. It remains to be seen whether the newly synthesized, more selective antiprogestins will prove more efficacious in the clinical arena.     

Unusually young Merkel cell carcinoma patients are Merkel cell polyomavirus positive and frequently immunocompromised

Merkel cell carcinoma (MCC) is a rare neuroendocrine carcinoma typically affecting the elderly. Only 5% to 10% of the patients are younger than 50 years at the time of the diagnosis. The purpose of this study was to compare the tumour and disease characteristics between exceptionally young and the typical elderly MCC population. Further, quantitative polymerase chain reaction analysis was used to study for Merkel cell polyomavirus (MCPyV) in their primary MCC tumours. Patients diagnosed with MCC in Finland from 1979 to 2004 were identified from the files of the Finnish Cancer Registry. Presence of MCPyV DNA in tumour samples was investigated using quantitative polymerase chain reaction. Six of 181 MCC patients were ≤50 years, with male-to-female ratio of 1:1. An altered immune condition state was observed in five patients. The Kaplan–Meier analysis showed a trend towards worse MCC-specific survival both in 5- and 10-year surveillance for younger patients. Five primary tumour tissue samples, available for analysis, contained MCPyV DNA. Our data shows that MCC, ≤50 years of age, is rarer then previously estimated. Moreover, our data showed marked differences both in patient demographics and in primary tumour characteristics as compared to surveys including older MCC patients. Course of disease seemed to be worse in the exceptionally young patients. All MCC primary tumours in this study contained MCPyV DNA.