What's new in resuscitation strategies for the patient with multiple trauma?

The last decade has seen a sea change in the management of major haemorrhage following traumatic injury. Damage control resuscitation (DCR), a strategy combining the techniques of permissive hypotension, haemostatic resuscitation and damage control surgery has been widely adopted as the preferred method of resuscitation in patients with haemorrhagic shock. The over-riding goals of DCR are to mitigate metabolic acidosis, hypothermia and coagulopathy and stabilise the patient as early as possible in a critical care setting. This narrative review examines the background to these changes in resuscitation practice, discusses the central importance of traumatic coagulopathy in driving these changes particularly in relation to the use of high FFP:RBC ratio and explores methods of predicting, diagnosing and treating the coagulopathy with massive transfusion protocols as well as newer coagulation factor concentrates. We discuss other areas of trauma haemorrhage management including the role of hypertonic saline and interventional radiology. Throughout this review we specifically examine whether the available evidence supports these newer practices.

Incidental thyroid carcinoma identified by positron emission tomography scanning obtained for metastatic evaluation.

Positron emission tomography (PET) scanning is an emerging technology with substantial implications for patients with solid tumors. PET is useful in identifying sites of metastatic disease as well as primary malignancy and evaluating suspicious findings found via other imaging modalities. PET is becoming a standard modality for metastatic evaluation of a variety of malignancies. However, this imaging is not limited by histology and may reveal clinically occult second lesions. We present five cases of a clinically occult thyroid cancer found in patients who underwent PET scanning for metastatic evaluations. The principal diagnoses included two patients with malignant melanoma, one each with gastric, rectal, and colonic adenocarcinoma. None of the cases had findings on physical examination. Increased uptake in the region of the thyroid was evident on the PET scan, and fine-needle aspiration biopsy indicated papillary carcinoma of the thyroid in all five cases. Although evaluation of metastatic disease is the primary purpose for PET in this setting the discovery of occult thyroid malignancy is an additional benefit of such imaging. This emphasizes the importance of investigating suspicious areas found by PET and not simply assuming that these are all sites of metastatic disease. Furthermore incidental findings of uptake in the region of the thyroid make consideration of a primary carcinoma mandatory.

Automated solid-phase synthesis of linear nitrogen-linked compounds.

A synthetic library motif has been developed to create linear, nitrogen-linked compounds as screening libraries to target structured RNA for drug discovery. Scaffolds were created in situ from suitably protected bifunctional compounds linked together either by acyl or amine links. Acyl links were created from amino acids, which also introduce one degree of functionality. Amine links from the amino acid nitrogen were created from an N-protected amino alcohol via Fukuyama Mitsunobu alkylation. Each amine site can then be used for introducing functionality or extending the scaffold. This synthetic scheme can be used to create a wide variety of modified-backbone PNA in situ, as shown by the synthesis of a PNA-type monomer. The synthesis steps have been enabled on a 96-well parallel-array synthesizer for high-throughput synthesis. The present study represents a versatile synthetic approach to a wide variety of potential RNA-binding molecules.

A new method for introducing amidate linkages in oligonucleotides using phosphoramidite chemistry.

Cyanoethyl-protected phosphotriester links in oligonucleotides made with standard pophosporamidite chemistry were converted to pbosphoramidate linkages during oligonucleotide synthesis on solid support. The cyanoethyl group was removed with piperidine, and the resulting phosphodiester was activated with p-tosyl chloride. An amine nucleophile displaced the tosyl to yield a phosphoramidate linkage.

"Blind" placement of long-term central venous access devices: report of 589 consecutive procedures.

Placement of long-term central venous access devices, such as Hickman catheters and implanted subcutaneous ports, has traditionally been performed in the operating room with fluoroscopy. This study reports our experience with percutaneous placement of these devices in the outpatient clinic setting without the use of real-time imaging. Results were generated from a prospective database of all adult patients undergoing placement of central venous access in the outpatient clinic of the Wake Forest University Baptist Medical Center. This database revealed that during the years 1996 and 1997, long-term central venous catheter placement was attempted in 589 adult patients in the outpatient clinic. Technical success was achieved in 558 patients (92%). This included 278 tunneled catheters and 280 totally implanted devices. Repositioning of the catheter tip was required in 16 patients (2.9%). The incidence of pneumothorax was 1.9 per cent. Late complications, including infection and thrombosis, occurred in 9 per cent. The average procedure-related charge for placement of a single-lumen central venous port in the outpatient clinic was $1691 versus $4559 in the operating room and $3890 in the radiology department. We conclude that routine placement of long-term central venous access devices in the outpatient clinic, without the use of real-time imaging, yields acceptable success rates and may have economic advantages over procedures performed in the operating room or radiology department.

Flexible sigmoidoscopy. Illuminating the pearls for passage.

As efforts to improve screening for colon cancer have increased, so has the importance of routine flexible sigmoidoscopy. However, the procedure is still underused, and about half of primary care physicians who recommend it refer their patients to other physicians. Increased use of this valuable screening tool is an important goal in primary care practice. Drs Davis and Stanfield discuss the indications, contraindications, and goals of the procedure as well as special techniques and maneuvers that ensure its safety and efficiency.

DNA strand breaks and phosphatidylserine redistribution in newly ovulated and cultured mouse and human oocytes: occurrence and relationship to apoptosis.

This study determined the occurrence of two molecular markers of apoptosis, chromosomal DNA strand breaks and oolemma phosphatidylserine redistribution, in >200 uninseminated and unfertilized human oocytes, and >800 newly ovulated and cultured mouse oocytes. DNA breaks were analysed by terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling (TUNEL) and phosphatidylserine by annexin V staining, with imaging by conventional epifluorescence and scanning laser confocal fluorescence microscopy. More than 300 intact and 500 fragmented mouse oocytes were examined at 24 h intervals during 6 days of culture in three different types of medium. For the human, 205 oocytes were examined at retrieval or at 24 h intervals during 7.5 days of culture in two types of medium. The perifollicular vascularity and the dissolved oxygen content of follicular fluid were determined for most of the follicles from which human oocytes were derived. The results demonstrate that TUNEL fluorescence of metaphase II (MII) chromosomes and annexin V staining of the oolemma in newly ovulated and cultured mouse and human oocytes are rare, and, when detected, are not spatially or temporally related. This finding also applied to mouse oocytes that fragmented during culture and exhibited morphological features that grossly resembled apoptotic body formation. In contrast, TUNEL but not annexin V staining occurred in the first polar body of a relatively high proportion of newly ovulated mouse oocytes, but was rarely detected in newly aspirated human oocytes. For the human, the occurrence of MII chromosomal TUNEL fluorescence was patient-specific and unrelated to perifollicular vascularity or dissolved oxygen content of the corresponding follicular fluid. The pattern of chromosomal TUNEL fluorescence observed in the first polar body and in the MII chromosomes of a very small number of mouse and human oocytes, especially after many days of culture, suggests that DNA strand breaks may not arise by apoptosis-associated endonuclease digestion. The results with these two markers suggest that it is premature to conclude that apoptosis occurs in ovulated oocytes or that such a mechanism is involved in the elimination or prevention of fertilization of oocytes with cytoplasmic or chromosomal defects.

Solid-phase synthesis of a library of functionalized aminodiol scaffolds.

A combinatorial library motif has been developed based on orthogonally protected aminodiol scaffolds. Amine functionality was derivatized by commercially available electrophiles including carboxylic acids, sulfonyl chlorides, isocyanates, and aldehydes. A hydroxyl moiety was converted to a carbamate linkage, allowing a variety of amines to be incorporated. The scaffold was anchored to TentaGel at the second hydroxyl via a succinyl linker, which was hydrolyzed by mild aqueous basic conditions. The method was used to make a library of about 17,000 different members in mixtures of 5 per sample.

Deconvolution of combinatorial libraries for drug discovery: experimental comparison of pooling strategies.

An experimental evaluation of several different pooling strategies for combinatorial libraries was conducted using a library of 810 compounds and an enzyme inhibition assay (phospholipase A2). The library contained compounds with varying degrees of activity as well as inactive compounds. The compounds were synthesized in groups of three and pooled together in various formats to realize different pooling strategies. With one exception, all iterative deconvolution strategies and position scanning resulted in identification of the same compound. The results are in good agreement with the predicted outcome from theoretical and computational methods. These data support the tenet that active compounds for pharmaceutically relevant targets can be successfully identified from combinatorial libraries organized in mixtures.

Kinetics of G-quartet-mediated tetramer formation.

The phosphorothioate and phosphodiester oligodeoxynucleotides d(TTGGGGTT) form parallel-stranded tetramer structures stabilized by guanosine quartets. The phosphorothioate tetramer has been shown to inhibit human immunodeficiency virus (HIV) in vitro. The kinetics of association and dissociation of both tetramers have been determined as a function of temperature using size exclusion chromatography to measure the ratio of single strand to tetramer. In phosphate buffered saline (pH 7.2) at 37 degrees C, the fourth-order association rate of the phosphorothioate tetramer was 6.1 (+/- 0.5) x 10(4) M-3 s-1; the dissociation rate was 8.2 (+/- 0.2) x 10(-6) min-1, resulting in a t(1/2) of about 60 days. The association rate of the phosphodiester was about one order of magnitude faster and the dissociation rate about one order of magnitude slower than that of the phosphorothioate tetramer. The association reaction had a negative energy of activation for both compounds. Despite thermodynamic instability of the tetramer at low concentrations, the extremely slow dissociation rate may allow use of the phosphorothioate tetramer for AIDS chemotherapy.

Threats of corporal punishment as verbal aggression: a naturalistic study.

This study examined firsthand observations of adults (N = 70) making public verbal threats to physically punish or hurt children. While many adults threatened the child with a "spanking," most used a variety of other terms, some euphemistic and some menacing, to label the threatened event. Angry shouting seemed rare, and swearing was almost nonexistent. Many threatening adults, however, also hit the child. In the course of threatening their children, adults typically attributed unshared responsibility for group problems to the child. They also normalized their own aggression by acting as though nothing unusual had happened. Perhaps for tactical reasons, most children also reacted as though there were nothing unusual about the threat. No one inside or outside the group intervened. It is argued that a complete understanding of verbal aggression against children requires an appreciation of the ongoing interaction in which episodes are embedded, and of the immediate social context in which episodes develop. Public places may be an important facilitative context because of the expectations associated with a parent's public persona.

Childhood aggression and peer relations in the context of family and neighborhood factors.

4 models (risk, protective, potentiator, and person-environment fit) comparing the associations among ethnicity, income, and structural characteristics of families and neighborhoods on childhood aggression and peer relations were explored. The 1,271 second- through fifth-grade (M = 9.9 years) children were assigned to 1 of 8 family types based on ethnicity, income, and household composition, and their addresses were used to define low- or middle-SES neighborhoods using neighborhood census data. Middle-SES neighborhoods operated as a protective factor for reducing aggression among children from high-risk families, interacted with family type to produce poor person-environment fit resulting in a greater likelihood of being rejected by one's peers, and potentiated the development of home play companions for children from low-risk families. Developmental and gender differences were also explored. Results are discussed in terms of the need for broader contextual factors to be considered in studying children's social and behavioral development.

ATP content of human oocytes and developmental potential and outcome after in-vitro fertilization and embryo transfer.

The relationship between the ATP content of mature human oocytes and developmental potential after uterine transfer of sibling embryos was examined in 20 non-male factor in-vitro fertilization (IVF) patients matched for age, fertility history, ovarian stimulation protocol, oocyte quality and number, stage and morphology of embryos at uterine transfer. ATP content was determined for uninseminated and unfertilized oocytes for each cohort, and for embryos that developed after dispermic fertilization or which showed significant fragmentation. The effect of reduced ATP content on meiotic maturation, fertilization and preimplantation development was examined in cultured mouse oocytes treated with uncouplers of mitochondrial oxidative phosphorylation. The results demonstrated that meiotic maturation occurs in both mouse and human oocytes over a wide range of ATP contents, and that the ATP content of normal-appearing, metaphase II human oocytes can differ significantly between cohorts; however, a higher potential for continued embryogenesis and implantation in the human is associated with embryos that develop from cohorts of oocytes with ATP contents > or = 2 pmol/oocyte. The findings are discussed with respect to possible aetiologies and developmental consequences for embryonic development of different oocyte ATP contents, and the extent to which mitochondrial function may determine or influence the continued developmental capacity of embryos which appear normal and developmentally viable at the early cleavage stages.

A retrospective analysis of unfertilized and presumed parthenogentically activated human oocytes demonstrates a high frequency of sperm penetration.

A total of 518 normal-appearing, meiotically mature human oocytes that were judged unfertilized after insemination in vitro were examined for sperm penetration by conventional fluorescence and laser scanning confocal microscopy with DNA-specific probes. A similar analysis was performed on 29 single pronuclear oocytes that were presumed to originate by spontaneous (parthenogenetic) activation. The results demonstrate that 22% of the unfertilized oocytes and 52% of the presumed parthenogenetic oocytes were actually penetrated. Sperm penetration occurred in both normozoospermic and male factor cases. The findings indicate the importance of penetration analysis in determining the causes of fertilization failure that may reside with the male or female gamete, especially when assessing the utility of and necessity for assisted fertilization in subsequent attempts. The results also suggest that the cytoplasmic capacity to decondense sperm DNA may decline more rapidly than the ability of the oocyte to be penetrated and to mount an effective block to polyspermy.

The developmental ability of human oocytes penetrated at the germinal vesicle stage after insemination in vitro.

This study demonstrates that sperm penetration into the ooplasm occurs at high frequency in germinal vesicle (GV) stage human oocytes which failed to resume meiosis after ovulation induction in cycles of ovarian hyperstimulation for in-vitro fertilization. The capacity of the immature human oocyte to prevent polyspermic penetration at the cell surface level was suggested by the finding that despite the presence of numerous spermatozoa within the zona pellucida and on the oocyte surface within 3 h after insemination, all normal-appearing GV stage oocytes examined in this study were penetrated by a single spermatozoon. This notion was also supported by scanning confocal microscopic analysis of oocytes double-stained for DNA and cortical granules which showed highly localized regions of cortical granule-free cytoplasm in proximity to the penetrated spermatozoon. The developmental ability of these oocytes was assessed by culture in vitro. The results show that oocytes penetrated by a spermatozoon at the GV stage resume meiosis, develop the capacity to decondense sperm DNA, abstrict both first and second polar bodies, and form a male pronucleus from the spermatozoon which enters the oocyte prior to the resumption of meiotic maturation. After penetration, sperm nuclei rapidly migrate to the centre of the oocyte and become juxtaposed with the germinal vesicle, suggesting the presence of a cellular mechanism which permits directed movement within the cytoplasm. The developmental ability of these oocytes and the normality of the resulting embryos are discussed.

Combinatorially selected guanosine-quartet structure is a potent inhibitor of human immunodeficiency virus envelope-mediated cell fusion.

The phosphorothioate oligonucleotide T2G4T2 was identified as an inhibitor of HIV infection in vitro by combinatorial screening of a library of phosphorothioate oligonucleotides that contained all possible octanucleotide sequences. The oligonucleotide forms a parallel-stranded tetrameric guanosine-quartet structure. Tetramer formation and the phosphorothioate backbone are essential for antiviral activity. The tetramer binds to the human immunodeficiency virus envelope protein gp120 at the V3 loop and inhibits both cell-to-cell and virus-to-cell infection.

Cytogenetic, cellular, and developmental consequences of cryopreservation of immature and mature mouse and human oocytes.

This study examined the effects of cryopreservation on cellular organization, chromosomal complement, and developmental potential of immature and mature mouse and human oocytes. Chromosomal analyses were performed by DNA fluorescence microscopy and karyotyping on the same metaphase II-stage oocytes before and after freezing. Cellular analyses involved electron microscopy, time-lapse video recording, and fluorescent-probe microscopy of cortical granules. The findings demonstrate that while profound cytoplasmic, nuclear, and nucleolar alterations occur in the immature oocyte during cryopreservation, an apparently normal nucleus and cytoplasm is re-established progressively after thawing and culture. The resulting oocytes mature at high frequency and for the mouse, are fertilizable and capable of normal preimplantation of embryogenesis. Cryopreservation of mature mouse and human oocytes is not accompanied by a significant increase in the frequency of aneuploidy. However, cryopreserved human oocytes, while fertilizable, arrest development during the early cleavage stages and display aberrant patterns of cytokinesis. The possible etiologies of developmental failure in the human embryo that may be related to oocyte cryopreservation, as well as the potential benefits of cryopreservation of the immature oocyte, are discussed with respect to clinical and commercial applications.

Structure of a small RNA hairpin.

The hairpin stem-loop form of the RNA oligonucleotide rCGC(UUU)GCG has been studied by NMR spectroscopy. In 10 mM phosphate buffer this RNA molecule forms a unimolecular hairpin with a stem of three base pairs and a loop of three uridines, as judged by both NMR and UV absorbance melting behavior. Distance and torsion angle restraints were determined using homonuclear proton-proton and heteronuclear proton-phosphorus 2-D NMR. These values were used in restrained molecular dynamics to determine the structure of the hairpin. The stem has characteristics of A-form geometry, although distortion from A-form occurs in the 3'-side of the stem, presumably to aid in accommodating the small loop. The loop nucleotides adopt C2'-endo conformations. NOE's strongly suggest stacking of the uracils with the stem, especially the first uracil on the 5'-side of the loop. The reversal of the chain direction in the loop seems to occur between U5 and U6. Loop structures produced by molecular dynamics simulations had a wide range of conformations and did not show stacking of the uracils. A flexible loop with significant dynamics is consistent with all the data.