Cost comparison of mechanically ventilated patients across the age span.

OBJECTIVE: To compare the use of mechanical ventilation and hospital costs across ventilated patients of all ages, preterm through adults, in a nationally representative sample. STUDY DESIGN: Secondary analysis of the 2009 Agency for Healthcare Research and Quality National Inpatient Sample. RESULTS: A total of 1 107 563 (2.8%) patients received mechanical ventilation. For surviving ventilated patients, median costs for infants ⩽32 weeks' gestation were $51000 to $209 000, whereas median costs for older patients were lower from $17 000 to $25 000. For non-surviving ventilated patients, median costs were $27 000 to $39 000 except at the extremes of age; the median cost was $10 000 for <24 week newborns and $14 000 for 91+ year adults. Newborns of all gestational ages had a disproportionate share of hospital costs relative to their total volume. CONCLUSION: Most intensive care unit resources at the extremes of age are not directed toward non-surviving patients. From a perinatal perspective, attention should be directed toward improving outcomes and reducing costs for all infants, not just at the earliest gestational ages.

Confirming routine stentograms after cystectomy is unnecessary.

OBJECTIVE: In the current trend of earlier discharge from hospital and minimizing costs with selective intervention instead of routine "standard" orders, most institutions have abolished routine radiographic imaging of the collecting system before stent removal in postcystectomy patients, although clear supportive data from the recent literature is scarce. We retrospectively reviewed our experience with routine postoperative stentograms in 100 cystectomies to confirm that our decision to omit the stentogram procedure does not compromise patient safety and well-being. METHODS: We retrospectively reviewed the records of 100 patients who underwent radical cystectomy for bladder cancer. All 100 patients (87 with ileal conduit and 13 with orthotopic neobladder reconstruction) had their ureteroenteric anastomoses stented with feeding tubes that were exteriorized. Retrograde stentogram was performed under fluoroscopic monitoring on postoperative days 7 to 9. The radiology reports were reviewed for any mention of extravasation. RESULTS: Extravasation was detected on the stentograms of 5 of 197 (2.5%) ureteroenteric anastomoses. Clinical signs suggestive of an anastomotic leak had preceded the imaging studies in 4 of the 5 cases. After expectant management, only 1 patient (1.0%) required intervention with percutaneous nephrostomy. CONCLUSIONS: The relatively low extravasation rate and the infrequent need for active intervention coupled with the fact that an anastomotic leak can usually be diagnosed on clinical grounds confirms that routine use of stentogram after ureteroenteric anastomoses is not justified. Our decision to perform postoperative stentograms selectively is appropriate.

Fournier's gangrene following penile self-injection with cocaine.

To date, there have been no reports of Fournier's gangrene following penile self-injection of cocaine. We report a case of cocaine-induced Fournier's gangrene requiring parenteral antibiotics followed by primary surgical debridement and delayed reconstructive procedure of penile skin.

New multi-determinant strategy for a group A streptococcal vaccine designed for the Australian Aboriginal population.

Infection with group A streptococci can result in acute and post-infectious pathology, including rheumatic fever and rheumatic heart disease. These diseases are associated with poverty and are increasing in incidence, particularly in developing countries and amongst indigenous populations, such as Australia's Aboriginal population, who suffer the highest incidence worldwide. Immunity to group A streptococci is mediated by antibodies against the M protein, a coiled-coil alpha helical surface protein of the bacterium. Vaccine development faces two substantial obstacles. Although opsonic antibodies directed against the N terminus of the protein are mostly responsible for serotypic immunity, more than 100 serotypes exist. Furthermore, whereas the pathogenesis of rheumatic fever is not well understood, increasing evidence indicates an autoimmune process. To develop a suitable vaccine candidate, we first identified a minimum, helical, non-host-cross-reactive peptide from the conserved C-terminal half of the protein and displayed this within a non-M-protein peptide sequence designed to maintain helical folding and antigenicity, J14 (refs. 8,9). As this region of the M protein is identical in only 70% of group A streptococci isolates, the optimal candidate might consist of the conserved determinant with common N-terminal sequences found in communities with endemic group A streptococci. We linked seven serotypic peptides with J14 using a new chemistry technique that enables the immunogen to display all the individual peptides pendant from an alkane backbone. This construct demonstrated excellent immunogenicity and protection in mice.

Functional analysis of IgA antibodies specific for a conserved epitope within the M protein of group A streptococci from Australian Aboriginal endemic communities.

The mucosa is one of the initial sites of group A streptococcal (GAS) infection and salivary IgA (sIgA) is thought to be critical to immunity. However, the target epitopes of sIgA and the function of sIgA in GAS immunity, in particular the role of accessory cells and complement, is largely unknown. We studied the aquisition and the function of sIgA specific for a conserved region epitope, p145 (sequence: LRRDLDASREAKKQVEKALE) of the M protein. Peptide 145-specific sIgA is highly prevalent within an Aboriginal population living in an area endemic for GAS and acquisition of p145-specific sIgA increases with age, consistent with a role for such antibodies in immunity to GAS. Human sIgA and IgG specific for p145 were affinity purified and shown to opsonize M5 GAS in vitro. Opsonization could be specifically inhibited by the addition of free p145 to the antibodies during assay. Opsonization of GAS was totally dependent on the presence of both complement and polymorphonuclear leukocytes, and, moreover, affinity-purified p145-specific sIgA was shown to fix complement in the presence of M5 GAS. These data show that mucosal IgA to this conserved region peptide within the M protein has an important role in human immunity against GAS and may be useful in a broad-based cross-protective anti-streptococcal vaccine.

Human antibodies to the conserved region of the M protein: opsonization of heterologous strains of group A streptococci.

A 20-mer peptide (p145) in the carboxyl-terminal region of the M protein of group A streptococci (GAS) has previously been defined as the target of bactericidal antibodies. Sequence analysis of seven field isolates from indigenous Australians living in an area highly endemic for GAS and five laboratory reference strains (encompassing nine unique serotypes plus three nontypeables) demonstrates that this region is highly conserved (sequence identity ranging from 65 to 95%) with six of the 12 sequences being identical to p145. Most of the sequence dissimilarity is contained within the last seven amino acids of p145. Competitive ELISA demonstrates that human antibodies specific for p145 cannot discriminate between p145 and synthetic peptides representing four from four of the variant sequences tested. Ig purified from endemic sera was able to opsonize each of the GAS isolates and free p145 as well as a peptide expressing a minimal conformational epitope within p145 (requiring amino acids between positions 2 and 13 of p145), but not an irrelevant peptide, were able to partially or completely inhibit opsonization of all isolates and reference strains. Thus adult endemic sera contain antibodies which are bactericidal for multiple GAS serotypes and which are specific for a sequence of 12 amino acids contained within the p145 region of the M protein.

Mapping of conformational B cell epitopes within alpha-helical coiled coil proteins.

An approach to mapping antigenic B cell epitopes within alpha-helical coiled coil proteins has been developed and applied to two proteins: Streptococcal M protein and C. elegans paramyosin protein UNC-15. Overlapping peptides derived from an alpha-helical coiled coil conformational epitope were embedded between helical flanking peptides derived from the completely unrelated GCN4 leucine zipper peptide. The resulting chimeric peptides exhibited helical propensity. Chimeric peptides were tested for antigenicity (recognition by antibody) or immunogenicity (production of appropriate antibody response). A conformational epitope within the Streptococcal M protein recognised by three mAbs spanned 12 residues. Analysis of chimeric peptides based on C. elegans UNC-15 has enabled fine mapping of the minimal B cell epitope recognised by monoclonal antibody NE1-6B2 to seven non-contiguous residues (spanning 15 residues); the footprint of contact residues involved in antibody recognition being restricted to the hydrophilic face of the helix and covering five helical turns. This chimeric peptide epitope when coupled to diphtheria toxoid was highly immunogenic in mice and antisera recognised the conformationally dependent native peptide epitope. This approach has the potential to map conformational epitopes and design minimal epitopes for use as vaccine candidates.

Mapping the minimal murine T cell and B cell epitopes within a peptide vaccine candidate from the conserved region of the M protein of group A streptococcus.

The highly conserved C-terminus of the M protein of group A streptococcus (GAS) is a promising vaccine candidate. An epitope within the conserved C-terminus of the M protein, peptide 145 (a 20-mer with the sequence: LRRDLDASREAKKQVEKALE), has been defined which is the target of opsonic antibodies in both humans and mice, and is recognized by the sera of most adults living in areas of high streptococcal exposure. However, due to potential cross-reactivity between T cells stimulated by this region of the M protein and host cardiac myosin, it is critical to define precisely the minimal protective epitopes within p145. Studies have shown that the immunodominant epitope expressed by p145 is conformational, occurring as an alpha-helical coiled-coil. To enable us to map the murine minimal B cell and T cell epitopes within p145, we have used a novel strategy that allowed us to present shorter sequences of p145 in a native-like conformation. The minimal B cell epitope was found to be contained within residues 7-20 of the p145 sequence, and we have shown that mice immunized with this region are able to generate antibodies that bind to and also opsonize the organism GAS. The T cell epitope is located at the N-terminal region of the p145 sequence, residues 3-14. We have managed, therefore, to define a vaccine candidate--a minimal opsonic B cell epitope within the p145 sequence--that does not incorporate a potentially deleterious T cell epitope.

Opsonic human antibodies from an endemic population specific for a conserved epitope on the M protein of group A streptococci.

This study demonstrates the presence of epitope-specific opsonic human antibodies in a population living in an area endemic for group A streptococci (GAS) infection. Antibodies recognizing a conserved C-terminal region epitope (p145, sequence in single letter amino acids: LRRDLDASREAKKQVEKALE) of the M protein of GAS were isolated from human patients by affinity chromatography and were shown to be of the immunoglobulin G1 (IgG1) and IgG3 subclasses. These antibodies could reduce the number of colonies of serotype 5 GAS in an in vitro opsonization assay by 71-92%, compared with an equal amount of IgG from control adult donors living in non-endemic areas and without antibodies to p145. Addition of the peptide, p145, completely inhibited this opsonization. Indirect immunofluorescence showed that p145-specific antibodies were capable of binding to the surface of M5 GAS whereas control IgG did not. Using chimeric peptides, which contain overlapping segments of p145, each 12 amino acids in length, inserted into a known helical peptide derived from the DNA binding protein of yeast, GCN4, we have been able to further define two minimal regions within p145, referred to as pJ2 and pJ7. These peptides, pJ2 and pJ7, were able to inhibit opsonization by p145 specific antibodies. Finally, we have observed an association between the age-related development of immunity to GAS and the acquisition of antibodies to the conserved epitope, p145, raising the possibility of using this epitope as a target in a prophylactic vaccine administered during early childhood.

Mapping a conserved conformational epitope from the M protein of group A streptococci.

The carboxyl terminus of the M protein of group A streptococci (GAS) is highly conserved and contains epitopes that have been shown to induce opsonic antibodies and protection against GAS infection. This region of the protein can also stimulate T cells, which can react in vitro with heart antigens. Since different segments of the carboxyl terminus may be involved in immunity to GAS and in the pathogenesis of autoimmune disease (rheumatic heart disease), it is important to precisely define critical epitopes. However, the M protein is known to be a coiled coil, and a critical immunodominant antibody-binding epitope within this region (peptide 145, a 20-mer with the sequence LRRDLDASREAKK-QVEKALE) is shown here to be conformational. Thus, small synthetic overlapping peptides of 8-12 amino acids in length that span peptide 145 (p145) were unable to capture antibodies present in p145-immune mouse sera or in endemic human sera, even though antibodies raised to these small peptides coupled to diphtheria toxoid could bind the smaller peptides and, in some cases, p145. A series of mutated peptides in which every residue of p145 was sequentially altered also failed to identify critical residues for antibody binding. We thus devised a strategy to produce chimeric peptides in which small peptides copying the M protein sequence were displayed within a larger 28-mer peptide derived from the sequence of the GCN4 leucine zipper DNA binding protein of yeast. A 12-amino-acid window of the p145 sequence was inserted into the GCN4 peptide in such a way as to preserve any potential helical structure. The window was moved along one residue at a time to give a series of peptides representing p145. Circular dichroism demonstrated that these larger chimeric peptides and p145, but not a shorter 12-mer peptide, displayed alpha-helical potential in 50% trifluoroethanol. Certain chimeric peptides efficiently captured antibodies specific for p145 and thus enabled us to map the minimal antibody-binding sequence. RRDLDASREAKK, referred to as J(1)2. The chimeric peptide containing this sequence, referred to as J2, was able to inhibit opsonization of GAS by human antisera containing anti-peptide 145 antibodies. The T-cell response from p145-immunized responder B10.BR mice to J2 and J(I)2 was much lower than the response to p145 and mapped to a different peptide.

Metastatic tumours of the testes.

Metastatic tumours of the testes are uncommon, making up little more than 2% of all testicular neoplasms. The most frequent primary sites are the lung and prostate. Only rarely do these lesions present clinically either as the first sign of malignant disease or as a complicating factor during the course of known disease. The authors present two cases illustrating both of these occurrences. The first, a man with carcinoma of the common bile duct, initially had a mass in the testicle and the second, a patient with carcinoma of the prostate, had his clinical course complicated by a symptomatic metastasis to the right testis. The authors also reviewed their local autopsy experience and identified 16 more cases. Metastases were grossly visible in 38% (6 of 16). The most frequent primary sites were lung (four cases), stomach (four) and prostate (three). Routes of spread as well as possible explanations for the low incidence are discussed.

Epidermoid cyst of the testes.

Malignant tumors of the testis are the leading cause of cancer death in men between 25 and 34 years old. Benign tumors of the testis are rare, accounting for less than 1% of all testicular tumors. We report 2 cases of epidermoid cysts of the testis and review the literature.

Spontaneous rupture of the renal pelvis: complication of renal homotransplantation.

The first reported case of rupture of the renal pelvis associated with transplantation is presented. The obstruction was in the ureteral tunnel of the hypertrophic bladder. The cause of the weakness in the pelvic wall could not be determined. Differential diagnosis was acute rejection and lymphocele. Excretory urography was diagnostic. Treatment included revision of the ureteroneocystostomy with repair of the defect and internal stenting. Postoperative morbidity was minimal and satisfactory graft function was maintained.