Molecular typing of a suspected cluster of Nocardia farcinica infections by use of randomly amplified polymorphic DNA, pulsed-field gel electrophoresis, and amplified fragment length polymorphism analyses

Randomly amplified polymorphic DNA (RAPD), pulsed-field gelelectrophoresis (PFGE), and amplified fragment length polymorphism (AFLP) analyses were used to investigate a possible outbreak of Nocardia farcinica. RAPD and PFGE analyses yielded irreproducible and unsatisfactory results, respectively. AFLP analysis seem to be a promising and welcome addition for molecular analysis of Nocardia isolates.     

Pediatric Dose Selection and Utility of PBPK in Determining Dose

Interest in determining safe and efficacious doses for drug administration in pediatric patients has increased dramatically in recent years. However, published pediatric clinical studies have failed to increase proportionally with adult clinical study publications. In order to assess the current state of pediatric dose determination and the supporting role of physiologically based pharmacokinetic modeling and simulation in determining pediatric dose, the pediatric clinical literature (2006–2016) and case examples of pediatric PBPK modeling efforts were reviewed. The objective of this assessment was to investigate the contribution of PBPK to our understanding of the differences between children and adults, which lead to differences in drug dose. Pediatric and adult dose data were available for 31 small molecule drugs. In general, pediatric dose was well-correlated with adult data, with an apparent tendency for higher body weight- or body surface area-normalized pediatric dose. Overall performance of pediatric PBPK modeling approaches was considered to adequately predict observed data. However, model performance was dependent upon age group simulated, with approximately half of neonatal predictions falling outside of 1.5-fold of observed. In conclusion, there is a clear need for further refinement of starting dose in pediatric phase 1 studies, and utilization of PBPK could lead to reduced numbers of patients required to establish safe and efficacious doses in the pediatric population.     

Surgical ventricular reconstruction and subendocardial resection for the treatment of refractory ventricular tachycardia

We describe a case of 64-year-old female patient with ventricular tachycardia intractable to medical treatment and acute heart failure following myocardial infarction. Emergency surgical ventricular reconstruction and subendocardial resection was undertaken. We discuss the option of surgical intervention in this difficult and unusual clinical scenario.     

Patterns of HIV-1 evolution in individuals with differing rates of CD4 T cell decline

Evolution of HIV-1 env sequences was studied in 15 seroconverting injection drug users selected for differences in the extent of CD4 T cell decline. The rates of increase of either sequence diversity at a given visit or divergence from the first seropositive visit were both higher in progressors than in nonprogressors. Viral evolution in individuals with rapid or moderate disease progression showed selection favoring nonsynonymous mutations, while nonprogressors with low viral loads selected against the nonsynonymous mutations that might have resulted in viruses with higher levels of replication. For 10 of the 15 subjects no single variant predominated over time. Evolution away from a dominant variant was followed frequently at a later time point by return to dominance of strains closely related to that variant. The observed evolutionary pattern is consistent with either selection against only the predominant virus or independent evolution occurring in different environments within the host. Differences in the level to which CD4 T cells fall in a given time period reflect not only quantitative differences in accumulation of mutations, but differences in the types of mutations that provide the best adaptation to the host environment.     

Differential coupling of CC chemokine receptors to multiple heterotrimeric G proteins in human interleukin-2-activated natural killer cells

Using two different approaches, we have investigated the types of G proteins coupled to CC chemokine receptors. First, permeabilization of interleukin-2-activated natural killer (IANK) cells with streptolysin-O and introduction of anti-G protein antibodies inside these cells resulted in the following. (1) Anti-G(s), anti-G(o), and anti-G(z) inhibited the migration of IANK cells in response to macrophage- inflammatory protein-1 alpha (MIP-1 alpha), monocyte chemoattractant protein-1 (MCP-1), or regulated on activation normal T cell expressed and secreted (RANTES). (2) Anti-Gi inhibited their migration in response to MCP-1 or RANTES but not in response to MIP-1 alpha. Second, incubation of IANK cell membranes with anti-G protein antibodies before incubating with (gamma-35S) GTP or (gamma-32P) GTP, resulted in the following. (1) Anti-G(s), anti-G(o), or anti-G(z) inhibited GTP binding and GTPase activity in the presence of MIP-1 alpha, or RANTES. (2) Anti- G(i) inhibited GTP binding and GTPase activity in the presence of MCP-1 or RANTES but not in the presence of MIP-1 alpha. The inhibitory effect of anti-G protein antibodies was reversed upon incubating these antibodies with their respective synthetic peptides before addition to IANK cell membranes. These results suggest that MCP-1 and RANTES receptors are promiscuously coupled to multiple G proteins in IANK cell membranes and that this coupling is different from MIP-1 alpha receptors, which seem to be coupled to G(s), G(o), and G(z) but not to G(i).     

Change in male secondary sexual characters in artificial interspecific hybrid populations.

The interfertile Hawaiian species Drosophila silvestris and Drosophila heteroneura were hybridized, forming reciprocal populations; the SH hybrid line was begun with D. silvestris female parents, and the HS hybrid line was begun with D. heteroneura female parents. Mass laboratory cultures were maintained for 14 generations without artificial selection. The species differ strikingly in two male secondary sexual characters, head shape and foreleg tibial cilia number. These characters are known to be quantitative characters that are influenced by both sex-linked and autosomal factors and appear to be involved in sexual selection. In the later generations (4-14), head shape in SH flies changes significantly; cilia number changes in both SH and HS populations. In terms of the parental phenotypes, the SH population evolved toward a heteroneura-like head while simultaneously evolving toward a silvestris-like tibia. In the HS population, there was no significant change in head shape, but cilia number decreased, making it more like the parental heteroneura. Accordingly, these two secondary sexual characters pursue separate evolutionary pathways. We suggest that these changes are brought about by selection occurring naturally during the later generations.     

Clinical features and outcome in childhood T-cell leukemia-lymphoma according to stage of thymocyte differentiation: a Pediatric Oncology Group Study

The immunophenotypes of lymphoblasts from children with newly diagnosed T-cell acute lymphoid leukemia (T-ALL, n = 101) or T-cell non-Hodgkin lymphoma (T-NHL, n = 31) were analyzed to correlate stage of thymocyte differentiation with clinical features and outcome. The 67 boys and 34 girls with T-ALL were 1 month to 18 years old (median, 8 years) with leukocyte counts ranging from 2 to 810 x 10(9)/L (median, 55 x 10(9)/L). Eighteen of these patients were black, and 70 had a mediastinal mass. Twenty-six boys and five girls with a median age of 9 years (range, 1 to 20 years) had T-NHL. Seven of these patients were black, and 24 had a mediastinal mass. The distributions of thymocyte developmental stages (early [CD7+], intermediate [CD1+ and/or CD4+ and/or CD8+], and mature [CD3+]) in cases of T-ALL and T-NHL were significantly different: 34%, 43%, and 23% v 6%, 62%, and 32% (P = .02). A comparison of the patients' clinical features according to the maturational stage of thymocytes failed to disclose significant differences in the majority of characteristics studied. However, patients with mature-stage T-NHL, with or without the addition of subjects with mature-stage T-ALL, were less likely to have a mediastinal mass (P = .02 for both comparisons). Those with intermediate-stage T-cell malignancy (T-ALL and T-NHL combined) were the subgroup most likely to have a mediastinal mass (P = .01). Response to remission induction therapy was significantly worse in the T-ALL subgroup with an early-stage phenotype: a failure rate of 21% v 0% and 6% for the two more differentiated phenotypic subgroups (P = .007). Event-free survival was not affected by thymocyte maturational stage in cases of either T-ALL or T-NHL. Despite evidence of clinical heterogeneity among the maturational stages of T-cell malignancies in children, these developmental subdivisions do not appear to be critical determinants of outcome once remission is achieved. We conclude that such phenotypes need not be included in the stratification plans for clinical trials using common induction treatment.     

Identification of a second transforming gene, rasn, in a human multiple myeloma line with a rearranged c-myc allele

Multiple myeloma is a disease characterized by a long, slowly progressive phase and a final, more aggressive one. Little is known about the mechanism of transformation of myeloma cells, although the clinical characteristics of the disease suggest a multi-step process. Recently, a myeloma cell line, NCI-H929, was isolated from a patient with aggressive preterminal disease and found to have a rearranged myc allele. This myeloma cell line has been further characterized in a focus formation assay to determine whether its unusual growth characteristics were associated with a second activated transforming gene. We now report that the NCI-H929 myeloma cell line has an activated rasn allele in addition to a rearranged myc allele. This is the first identification of an activated transforming gene in a multiple myeloma cell line; furthermore, the characterization of two independently activated oncogenes in this B cell malignancy has implications for both the pathogenesis and evolution of the disease.     

Lower limb injuries caused by improvised explosive devices: Proposed ‘Bastion classification’ and prospective validation

Background

Complex lower limb injury caused by improvised explosive devices (IEDs) has become the signature wounding pattern of the conflict in Afghanistan. Current classifications neither describe this injury pattern well, nor correlate with management. There is need for a new classification, to aid communication between clinicians, and help evaluate interventions and outcomes. We propose such a classification, and present the results of an initial prospective evaluation.

Patients and methods

The classification was developed by a panel of military surgeons whilst deployed to Camp Bastion, Afghanistan. Injuries were divided into five classes, by anatomic level. Segmental injuries were recognised as a distinct entity. Associated injuries to the intraperitoneal abdomen, genitalia and perineum, pelvic ring, and upper limbs, which impact on clinical management and resources, were also accounted for.

Results

Between 1 November 2010 and 20 February 2011, 179 IED-related lower limb injuries in 103 consecutive casualties were classified, and their subsequent vascular and musculoskeletal treatment recorded. 69% of the injuries were traumatic amputations, and the remainder segmental injuries. 49% of casualties suffered bilateral lower limb amputation. The most common injury was class 3 (involving proximal lower leg or thigh, permitting effective above-knee tourniquet application, 49%), but more proximal patterns (class 4 or 5, preventing effective tourniquet application) accounted for 18% of injuries. Eleven casualties had associated intraperitoneal abdominal injuries, 41 suffered genital or perineal injuries, 9 had pelvic ring fractures, and 66 had upper limb injuries. The classification was easy to apply and correlated with management.

Conclusions

The ‘Bastion classification’ is a pragmatic yet clinically relevant injury categorisation, which describes current injury patterns well, and should facilitate communication between clinicians, and the evaluation of interventions and outcomes. The validation cohort confirms that the injury burden from IEDs in the Helmand Province of Afghanistan remains high, with most casualties sustaining amputation through or above the knee. The rates of associated injury to the abdomen, perineum, pelvis and upper limbs are high. These findings have important implications for the training of military surgeons, staffing and resourcing of medical treatment facilities, to ensure an adequate skill mix to manage these complex and challenging injuries.