Effects of blast exposure on exercise performance in sheep

BACKGROUND

The effects of blast on maximal exercise performance were investigated in sheep that were trained to perform maximal exercise.

METHODS AND RESULTS

Sheep were fully instrumented for determination of pulmonary and systemic hemodynamics. Blast exposure was administered by using a compressed air driven shock tube that was positioned to primarily produce cardiopulmonary injury. Four levels of exposure were used that were known to produce sublethal injury ranging from little or no grossly observable cardiopulmonary injury (level 1) to confluent ecchymosis of the heart, lung, or both (level 4). We evaluated maximal exercise performance 1 hour after exposure to level 1, level 2, and level 3 and 24 hours after level 3 and level 4. VO2max was not significantly decreased 1 hour after exposure to level 1 but was decreased after exposure to level 2 (29.9%) and level 3 (49.3%). Significant improvement in exercise performance was observed in 24 hours, as VO2max was not significantly decreased 24 hour after level 3. VO2max was decreased 24 hour after level 4 injury (30.8%).

CONCLUSION

Cardiovascular data collected during exercise suggested that acute cardiopulmonary injury is responsible for the exercise performance decrement observed 1 hour after exposure and that significant recovery of function is observed 24 hours after blast injury.

Tight junction proteins ZO-1, ZO-2, and occludin along isolated renal tubules

BACKGROUND

Tight junctions play a critical role in tubular function. In mammalian kidney, the transepithelial electrical resistance and the complexity of the tight junction increase from the proximal to the collecting tubule. The differential expression of three tight junction proteins, ZO-1, ZO-2, and occludin, along isolated rabbit renal tubules is examined in this article.

METHODS

Microdissected rabbit renal tubules were processed for immunofluorescence detection of ZO-1, ZO-2, and occludin. The quantitation of these proteins was done by Western blot determinations in Percoll isolated tubules.

RESULTS

ZO-1 stained cell boundaries independently of the identity of the tubule. However, the amount found in distal segments was significantly higher than that expressed in proximal regions. ZO-2 in the proximal region was found diffusely distributed in the cytoplasm, with faint staining at cell borders, while a clear signal at cell perimeters was detectable from the Henle's loop to collecting tubules. Nuclear staining of ZO-2 was found along the whole nephron. The presence of occludin at the proximal region was faint and discontinuous, while its expression in the more distant portions was conspicuous. The quantity of ZO-2 and occludin present at the distal region was significantly higher compared with the proximal segment.

CONCLUSIONS

The distribution of ZO-1, ZO-2, and occludin follows the increase in junction complexity encountered in renal tubules. The amount of the three proteins found in proximal and distal segments is significantly higher in the latter.

[The iliac crest. Perspective on a donor site of exceptional free flaps, 20 years after its initial description]

The iliac crest represents the principle 'reservoir' for the cortico-spongy bone. After having been used for a long time in the form of a conventional graft, it has been the object, in the last 20 years, of increasingly sophisticated transfers, making it possible to extract it in vascularized form. The authors present the anatomical bases of these transfers, which can be conceived on four different vascular axes: the superficial circumflex iliac axis, which was the first used, the deep circumflex iliac axis, the superior gluteal axis, and the lateral femoral circumflex axis. After having presented the various techniques of extraction of the anterior and posterior crests, the authors attempted to delineate the indications of each variant in the reconstruction of the members and the cervico-facial sphere. A comparison with the fibula flap will be finally carried out in order to parallel the advantage and respective disadvantages of these two transfers.

RDP: detection of recombination amongst aligned sequences

SUMMARY

Recombination Detection Program (RDP) is a program that applies a pairwise scanning approach to the detection of recombination amongst a group of aligned DNA sequences. The software runs under Windows95 and combines highly automated screening of large numbers of sequences with a highly interactive interface for examining the results of the analyses.

[The scapula: a preferred donor site for a free flaps or pedicles transfer]

The authors present all the possibilities that the scapula can offer as a donor site for bone. After having reviewed the potential for acromial transfer on a pedicled trapezial flap, they summarise the anatomical basis for the transfer of the lateral border. There are two systems of vascular supply, one based on the circumflex scapular vessels described by Téot and the other based on the vessels of the angle of the scapula described by Deraemacker. This dual blood supply forms a very rich anastomosis with a predominant periosteal supply that allows for multiple osteotomies to be made. The technique of harvesting and the indications are highlighted as well as an iconography, which presents the principle forms of reconstruction that have been described until today. The authors support the use of the pedicled transfer of the lateral border, which is poorly known and above all poorly used. Their experience in five consecutive clinical cases demonstrates all the potential of this technique for humeral reconstruction. As a microsurgical transfer, however, the principal advantage of using the inferior scapular axis is offset by a few drawbacks, the principal one being the difficulty of dissection. Its main indication as a free flap is in the maxillofacial surgery where it allows very precise reconstructions of the mandible, the palate or the maxillozygomatic region.

Effects of intrapartum administration of invert sugar and D5LR on neonatal blood glucose levels

OBJECTIVE

To compare the effects of D5LR and invert sugar administered intrapartum on neonatal blood glucose concentrations.

STUDY DESIGN

This is a prospective, randomized, double-blind study. A total of 32 insulin-requiring diabetic patients were randomized to receive either intravenous 10% invert sugar or lactated Ringer's solution with 5% dextrose (D5LR). Regular insulin was given intravenously with an infusion pump to maintain the plasma glucose concentration between 60 and 90 mg/dl. Neonatal blood glucoses were measured at 30 minutes after birth, four times every hour, and thereafter as indicated. Student's t-test was used for continuous variables and Fisher's exact test was used for categorical data.

RESULTS

There were no differences in neonatal blood glucose levels, incidence of neonatal hypoglycemia, or length of neonatal hospital stay between the two groups.

CONCLUSION

Intrapartum administration of invert sugar is not associated with better neonatal homeostasis of glucose compared with using D5LR. Thus, given the expense of invert sugar, D5LR appears to be preferable for intrapartum control of maternal blood glucose.

[Autologous bone grafts. Anatomo-physiology, technique and actual location for bone reconstructions]

The authors discuss the indications for conventional nonvascularized bone grafts, of which the scope of utilisation has been considerably reduced since the advent of vascularized bone grafts. The objective of this study is to highlight the essential knowledge regarding the biology and biomechanics of the incorporation of bone grafts. The principal donor sites are examined with respect to the operative techniques and the advantages and disadvantages. The authors then derive the principal indications for conventional bone grafting and illustrate them with examples selected for limb reconstruction.

Effect of oral creatine supplementation on isokinetic torque production

PURPOSE

This study was conducted to examine the effect of oral creatine supplementation on the decline in peak isokinetic torque of the quadriceps muscle group during an endurance test.

METHODS

Twenty-three active, but untrained, male subjects performed isokinetic strength tests on a Cybex II dynamometer at 180 degrees x s(-1). The protocol consisted of pre- and post-tests with five sets of 30 maximum volitional contractions with a 1-min rest period between sets. Subjects returned to perform the posttest after 5 d of placebo (4 x 6 g glucose x d(-1), N = 12) or creatine (4 x 5 g creatine + 1 g glucose x d(-1), N = 11) supplementation. Supplements and testing were administered in a double blind fashion. Peak torque was measured during each contraction and the 30 contractions were averaged for each set.

RESULTS

A three-way mixed ANOVA with one between factor (placebo vs creatine) and two within factors (pre/post supplementation and sets 1-5) revealed no significant interactions, P > 0.05. The placebo vs creatine main effect was also nonsignificant, whereas the pre/post and set effects were significant (P < 0.05). Peak torque increased (approximately 3%) from pre- to post-testing, (P = 0.04), but the absolute magnitude of the differences is unlikely to be of any practical significance. Peak torque decreased from sets 1 to 4, whereas sets 4 and 5 were not different. A priori contrasts comparing the creatine group's performance pre vs post test for the fourth and fifth sets were nonsignificant (P > 0.05).

CONCLUSIONS

Based on within and between group comparisons, we were unable to detect an ergogenic effect of oral creatine supplementation on the decline in peak torque during isokinetic exercise at 180 degrees x s(-1).

[Pseudo-inherited form of left heart obstructive defects revealing maternal phenylketonuria]

If an adequate diet is not given to mothers with phenylketonuria, their offsprings often exhibit intra-uterine growth retardation with associated microcephaly and various malformations. Here, we report two families in whom we observed recurrent left heart malformations associated with microcephaly masquerading as a mendelian condition and revealing a maternal phenylketonuria. These observations suggest that when confronted to recurrent heart malformations with extra-cardiac defects that are not due either to an inherited chromosomal anomaly or to a well characterized mendelian disease, a maternal teratogen should be identified and more particularly maternal hyperphenylalaninemia if an intra-uterine growth retardation or a microcephaly is part of the syndrome.

Human immunodeficiency virus-1 coat protein gp120 impairs contextual fear conditioning: a potential role in AIDS related learning and memory impairments

Many AIDS patients suffer from cognitive impairments including deficits in learning and memory. The Human Immunodeficiency Virus-1 (HIV-1) envelope glycoprotein gp120 is one possible mediator of these impairments. This is because gp120 activates brain microglial cells and astrocytes, and in vivo activation of glia leads to the release of the proinflammatory cytokine interleukin-1 beta (IL-1beta). gp120 induced IL-1beta release could be involved in producing memory impairments associated with AIDS because central IL-1beta activity adversely affects cognitive function. The reported experiments evaluated the effects of i.c.v. gp120 administration and subsequent IL-1beta activity on learning and memory processes in the rat. Intracerebroventricular gp120 produced memory impairments on hippocampally dependent contextual fear conditioning, but not hippocampally independent auditory-cue fear conditioning following post-conditioning gp120 administration. Central gp120 administration also caused increases in IL-1beta protein levels in the hippocampus and frontal cortex but not in the hypothalamus. gp120 induced memory impairments were blocked by 2 different IL-1 antagonists, alpha melanocyte stimulating hormone (alphaMSH) and interleukin-1 receptor antagonist (IL-1ra). Finally, heat denaturation of the tertiary structure of gp120 abolished its effects on fear conditioning, suggesting that gp120 impairs contextual fear conditioning by binding to its receptors on glia.

Thermal hyperalgesia and mechanical allodynia produced by intrathecal administration of the human immunodeficiency virus-1 (HIV-1) envelope glycoprotein, gp120

Astrocytes and microglia in the spinal cord have recently been reported to contribute to the development of peripheral inflammation-induced exaggerated pain states. Both lowering of thermal pain threshold (thermal hyperalgesia) and lowering of response threshold to light tactile stimuli (mechanical allodynia) have been reported. The notion that spinal cord glia are potential mediators of such effects is based on the disruption of these exaggerated pain states by drugs thought to preferentially affect glial function. Activation of astrocytes and microglia can release many of the same substances that are known to mediate thermal hyperalgesia and mechanical allodynia. The aim of the present series of studies was to determine whether exaggerated pain states could also be created in rats by direct, intraspinal immune activation of astrocytes and microglia. The immune stimulus used was peri-spinal (intrathecal, i.t.) application of the Human Immunodeficiency Virus type 1 (HIV-1) envelope glycoprotein, gp120. This portion of HIV-1 is known to bind to and activate microglia and astrocytes. Robust thermal hyperalgesia (tail-flick, TF, and Hargreaves tests) and mechanical allodynia (von Frey and touch-evoked agitation tests) were observed in response to i.t. gp120. Heat denaturing of the complex protein structure of gp120 blocked gp120-induced thermal hyperalgesia. Lastly, both thermal hyperalgesia and mechanical allodynia to i.t. gp120 were blocked by spinal pretreatment with drugs (fluorocitrate and CNI-1493) thought to preferentially disrupt glial function.

[Intrathoracic displacement of the transverse colon as a late complication after abdominal knife stab wound. A case report]

The treatment of stab wounds of the abdomen is discussed controversely. The management of these wounds depends on a high degree on the clinical situation of the patient. Repeated physical examination, peritoneal lavage and laparotomy are recommended. The identification of an isolated diaphragmatic injury is worrisome because its subtle clinical presentation is often not alleviated by adjunctive tests. Delayed recognition of an incarcerated diaphragmatic hernia has a high mortality rate. We report about an 23 year old African male, who was injured by an intraabdominal stab wound. Initially he did not have any clinical problems, but after 6 months he was admitted to the hospital due to severe pulmonary complications. A diaphragmatic hernia with dislocation of the transverse colon into the left thorax was identified on x-rays. A thoracotomy as well as a laparotomy were performed to restore the anatomic conditions and to dose the hernia. After two weeks, the patient could leave the hospital without pulmonary complications. Under consideration of the literature we recommend exploratory laparotomy for stab wounds that penetrate the left side of the chest below the fourth intercostal space anteriorly, the sixth intercostal space laterally and the tip of the scapula posteriorly. The high mortality rate after a delayed recognition appears to justify an early operative approach.

Protein trans-splicing and cyclization by a naturally split intein from the dnaE gene of Synechocystis species PCC6803

A naturally occurring split intein from the dnaE gene of Synechocystis sp. PCC6803 (Ssp DnaE intein) has been shown to mediate efficient in vivo and in vitro trans-splicing in a foreign protein context. A cis-splicing Ssp DnaE intein construct displayed splicing activity similar to the trans-splicing form, which suggests that the N- and C-terminal intein fragments have a high affinity interaction. An in vitro trans-splicing system was developed that used a bacterially expressed N-terminal fragment of the Ssp DnaE intein and either a bacterially expressed or chemically synthesized intein C-terminal fragment. Unlike artificially split inteins, the Ssp DnaE intein fragments could be reconstituted in vitro under native conditions to mediate splicing as well as peptide bond cleavage. This property allowed the development of an on-column trans-splicing system that permitted the facile separation of reactants and products. Furthermore, the trans-splicing activity of the Ssp DnaE intein was successfully applied to the cyclization of proteins in vivo. Also, the isolation of the unspliced precursor on chitin resin allowed the cyclization reaction to proceed in vitro. The Ssp DnaE intein thus represents a potentially important protein for in vivo and in vitro protein manipulation.

Terpenoid secondary metabolism in Arabidopsis thaliana: cDNA cloning, characterization, and functional expression of a myrcene/(E)-beta-ocimene synthase

The Arabidopsis genome project has recently reported sequences with similarity to members of the terpene synthase (TPS) gene family of higher plants. Surprisingly, several Arabidopsis terpene synthase-like sequences (AtTPS) share the most identity with TPS genes that participate in secondary metabolism in terpenoid-accumulating plant species. Expression of a putative Arabidopsis terpene synthase gene, designated AtTPS03, was demonstrated by amplification of a 392-bp cDNA fragment using primers designed to conserved regions of plant terpene synthases. Using the AtTPS03 fragment as a hybridization probe, a second AtTPS cDNA, designated AtTPS10, was isolated from a jasmonate-induced cDNA library. The partial AtTPS10 cDNA clone contained an open reading frame of 1665 bp encoding a protein of 555 amino acids. Functional expression of AtTPS10 in Escherichia coli yielded an active monoterpene synthase enzyme, which converted geranyl diphosphate (C(10)) into the acyclic monoterpenes beta-myrcene and (E)-beta-ocimene and small amounts of cyclic monoterpenes. Based on sequence relatedness, AtTPS10 was classified as a member of the TPSb subfamily of angiosperm monoterpene synthases. Sequence comparison of AtTPS10 with previously cloned monoterpene synthases suggests independent events of functional specialization of terpene synthases during the evolution of terpenoid secondary metabolism in gymnosperms and angiosperms. Functional characterization of the AtTPS10 gene was prompted by the availability of Arabidopsis genome sequences. Although Arabidoposis has not been reported to form terpenoid secondary metabolites, the unexpected expression of TPS genes belonging to the TPSb subfamily in this species strongly suggests that terpenoid secondary metabolism is active in the model system Arabidopsis.

Transport of phospholipid synthesis precursors and lipid trafficking into malaria-infected erythrocytes

Phospholipid biosynthesis in Plasmodium is of crucial importance considering the high degree of membrane biogenesis. In the de novo phosphatidylcholine pathway, the major plasmodial phospholipid, choline, first enters infected erythrocytes by a transport-mediated process, whose main kinetic characteristics are the same as in normal cells except for a considerable increase in Vm. The kinetic and functional characterizations of the choline carrier (affinity, specificity, stereoselectivity, asymmetric cyclic model, ionic dependence, limiting step in carrier translocation) have now been done, although there is no information concerning its nature and structure, despite the fact that it is likely an outstanding pharmacological target. Other unanswered questions concern the mechanisms for choline entry into the parasite. The intense lipid trafficking between the intracellular parasite and the host cell membrane also indicates that Plasmodium controls its own lipid composition as well as that of its host cell. Organelles that house the machinery for lipid synthesis, and mechanisms for trafficking and sorting, have not yet been described because of the lack of appropriate tools, but they could address fundamental questions in the contemporary cell biology of this parasite.

Inhibition of TNF-alpha can attenuate or exacerbate excitotoxic injury in neonatal rat brain

Tumor necrosis factor (TNF)-alpha, a multifunctional pro-inflammatory cytokine, has been implicated in the pathogenesis of acute ischemic brain injury. Recent data also suggest that TNF-alpha is a clinically relevant mediator of neonatal brain injury. We hypothesized that inhibition of TNF-alpha activity would reduce excitotoxic brain injury in neonatal rats. To test this hypothesis, we evaluated the efficacy of a TNF binding protein (bp) in attenuating NMDA-induced injury in 7 day old rats. Intrastriatal co-injection of TNFbp (3.75 microg) with NMDA (10 nmol) reduced striatal injury by 26%; in contrast, intra-hippocampal co-injection of TNFbp (3.75 microg) with NMDA (10 nmol) increased hippocampal damage by 68%. These findings indicate that TNF-alpha may have both beneficial and deleterious effects in the injured neonatal brain.

Stroke associated with marijuana abuse

We present the case of a 15-year-old with a cerebellar infarct that involved multiple arterial territories. It was temporally related to, and probably caused by, heavy marijuana use. While the mechanism of marijuana-associated stroke is unclear, the drug is known to cause hypotension and to impair peripheral vasomotor reflexes. We suspect that the child had diminished cerebral autoregulatory capacity and developed the stroke during a period of hypotension.

Soleus-fibula free transfer in lower limb reconstruction

Free-fibula transfer has been widely used since 1975. Many modifications have been described; one of them, association of the lateral part of the soleus muscle to the fibula, is reported here through a 14-case series. This composite flap is intended for extensive defects of the lower limbs involving bone and soft tissues. The flap is considered by the authors to be reliable, with a constant vascularization. A 20-cm length offibula may be harvested associated either with the lateral part of the soleus muscle or with the whole muscle. Moreover, the soleus muscle represents a vascular security inasmuch as it preserves both medullar and periosteal bone supply. Fourteen cases have been performed by the authors since 1978 and could be reviewed with a minimum 2-year follow-up. Average length of bone defect was 12 cm, and average length offibula harvested was 18.6 cm. Soft-tissue defect was always associated and ranged from 8 x 4 cm to 20 x 30 cm. The fibula was harvested with the lateral part of the soleus muscle in 10 cases and with the whole soleus muscle in 4 cases. One total treatment failure was reported and was related to intimal degenerative lesions on veins used for arteriovenous bypass. In other patients, mean time for bone healing was 11 months. Patients could walk again, on average, 17 months after reconstruction. Sequelae at the donor site were minimal.

[The modiolus. Comparative anatomy, embryological and physiological review, surgical importance]

Monkeys, imitators of man's gesture never shared smile with him and their facial expressions only result in grimaces. Study of animal anatomy may explain why subtle expressions of the lips are a more man's special gift than laughter. These fine movements are related to a subcutaneous muscular structure termed modiolus, which is the meeting point of muscles involved in the motion of mouth and comparative anatomy shows this structure to be better defined in Man than in other primates. Embryologically, muscles that form the modiolus derive from a cellular concentration in the region of the second branchial arch. It is then logical to see these muscles converge to the corner of the mouth to form the modiolus, as they emerge from a common area. Functioning of the modiolus is complex, as its position may change many times in a minute to allow the orbicularis oris muscle to take any position and do any movement as if it was inserted on bone. With its complex physiology, the modiolus is of critical importance in the subtle expressions of the lips and must be preserved or reconstructed when performing repair of full-thickness tissue defects of lips.

Surveillance for recurrent head and neck cancer using positron emission tomography

PURPOSE

Earlier detection of head and neck cancer recurrence may improve survival. We evaluated the ability of [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) to detect recurrence in a prospective trial using sequential PET scans.

PATIENTS AND METHODS

Serial posttherapy FDG-PET was prospectively performed in 44 patients with stage III or IV head and neck cancer. PET was performed twice during the first posttreatment year (at 2 and 10 months after therapy) and thereafter as needed. After therapy, patients were grouped, based on tissue biopsies, into those who achieved a complete response (CR) and those who had residual disease (RD). Patients who achieved a CR were further grouped into those without evidence of disease and those who had recurrence by 1 year after completion of therapy. Disease status as determined by physical examination (PE), PET, and correlative imaging was compared.

RESULTS

Eight patients were lost to follow-up and six had RD after therapy. Of the remaining 30 patients with a CR, 16 had recurrence in the first year after therapy. Five of these 16 patients had recurrence detected by PET only, four by PET and correlative imaging only, five by PE and PET only, and two by PE, correlative imaging, and PET. Only PET detected all recurrences in the first year. PET performed better than correlative imaging (P =.013) or PE (P =.002) in the detection of recurrence.

CONCLUSION

PET can detect head and neck tumor recurrence when it may be undetectable by other clinical methods. FDG-PET permits highly accurate detection of head and neck cancer recurrence in the posttherapy period.

Understanding dysfunctional and functional family behaviors for the at-risk adolescent

At-risk adolescents and their impact on families and society, as well as characteristics of both healthy and maladaptive families, are discussed. Cognitive distortions of dysfunctional adolescents and their effect on family members, along with methods for intervention and creating more healthy environments, are delineated from a systemic viewpoint.