Immunocytochemical localization of cell adhesion molecule L1 in developing rat pyramidal tract

L1 is a representative of a family of carbohydrate neural cell adhesion molecules. The expression of L1 was studied during postnatal development of the rat pyramidal tract by immunohistology using polyclonal antibodies to L1 in spinal cord cervical intumescences. On postnatal day 1 (P1), L1 immunoreactivity was present in the entire dorsal funiculus, consisting of the ascending fasciculus gracilis and fasciculus cuneatus and the descending pyramidal tract. At that time the cervical pyramidal tract contains the first outgrowing corticospinal axons. At P4 both the fasciculus gracilis and the pyramidal tract are immunoreactive whereas the fasciculus cuneatus is negative. At P10 the pyramidal tract is intensely labelled whereas both ascending bundles are negatively stained. In the period between P4 and P10 the pyramidal tract is characterized by a massive outgrowth of corticospinal axons. During pyramidal tract myelination, between P10 and the end of the third postnatal week (P21), L1 immunoreactivity is progressively reduced. These observations suggest that L1 may play a prominent role in outgrowth, fasciculation and the onset of myelination of rat pyramidal tract axons. The differential L1 immunoreactivity of the pyramidal tract and the earlier developing ascending systems in rat dorsal funiculus indicate that this polyclonal antiserum is a useful differentiating marker for outgrowing fibre tracts.     

Evaluation of an in situ setting injectable calcium phosphate as a new carrier material for gentamicin in the treatment of chronic osteomyelitis: studies in vitro and in vivo

A study was performed to investigate the effectiveness of hydroxyapatite cement (HAC) as a new carrier system in the treatment of chronic, posttraumatic osteomyelitis. In the in vitro study, release of gentamicin from standard cylinders of HAC were measured by agar diffusion test. As a representative for mechanical properties, compression strength was measured in order to detect changes when mixing HAC with gentamicin. In the in vivo study, bone infection was induced according to the model of Norden by injection of 1 ml Na-morrhuat and 3 x 10(6)CFU Staphylococcus aureus. After 3 weeks, when chronic stage of infection was obtained, 17 animals were treated by debridement and filling the marrow either with HAC alone or HAC mixed with gentamicin (32 mg/g). Animals of the control groups were left untreated. After 6 weeks, all animals were sacrificed. Hematological, radiological, microbiological and histological examinations were carried out by covered investigation. Best evidence of the efficiency of treatment was observed in histopathological and microbiological findings. In all swabs of the control groups, taken 6 weeks following infection S. aureus were detected which were clonal to the strain used for induction of osteomyelitis. In HAC/gentamicin-treated animals, no growth was detectable after 7 days of culturing in BHI bouillon. In the HAC/gentamicin-treated group, there was no histopathological evidence of infection. In all other groups different stages of chronic osteomyelitis were found. No side effect was observed, neither locally nor systemically by HAC or gentamicin. Therefore, HAC is considered to be a very effective carrier for antibiotics in treatment of chronic, posttraumatic osteomyelitis.     

Correction to: Neurocognitive functioning and health‑related quality of life of children after pediatric intensive care admission: a systematic review

Quality of Life Research -     

Validation of low-cost models for minimal invasive surgery training of congenital diaphragmatic hernia and esophageal atresia

BackgroundMinimal invasive surgery (MIS) is increasingly used for the correction of congenital diaphragmatic hernia (CDH) and esophageal atresia (EA). It is important to master these complex procedures, preferably preclinically, to avoid complications. The aim of this study was to validate recently developed models to train these MIS procedures preclinically.MethodsTwo low cost, reproducible models (one for CDH and one for EA) were validated during several pediatric surgical conferences and training sessions (January 2017–December 2018), used in either the LaparoscopyBoxx or EoSim simulator. Participants used one or both models and completed a questionnaire regarding their opinion on realism (face validity) and didactic value (content validity), rated on a five-point-Likert scale.ResultsOf all 60 participants enrolled, 44 evaluated the EA model. All items were evaluated as significantly better than neutral, with means ranging from 3.7 to 4.1 (p < 0.001). The CDH model was evaluated by 48 participants. All items scored significantly better than neutral (means 3.5–3.9, p < 0.001), with exception of the haptics of the simulated diaphragm (mean 3.3, p = 0.054). Both models were considered a potent training tool (means 3.9).ConclusionThese readily available and low budget models are considered a valid and potent training tool by both experts and target group participants.Type of studyProspective study.Level of evidenceLevel II.     

Local pharmacological manipulations of prefrontal dopamine affect conflict behaviour in rats

Several lines of research have implicated the prefrontal cortex (PFC) and its dopaminergic (DA) innervation in an animal's response to stress and anxiety. To extend these findings we evaluated the effects of bilateral infusions of DA drugs into the medial PFC of rats, in a modified conflict test, consisting of Reward, Conflict and Time-out components. In experiment 1, the effects of infusions of the DA receptor agonist apomorphine (APO) were compared to the effects of systemic injections of the same drug. APO infusions induced a dose-dependent decrease of responding in the Conflict component, indicative of an anxiogenic-like effect. However, response rates in the Reward component were simultaneously decreased, casting some doubt on the specificity of the effect. In comparison, i.p injections of APO in a second group of animals did not affect responding in the Conflict component, but dose-dependently decreased response rates during Time-out and Reward components. In experiment 2, we evaluated the effects of infusions of APO and the DA receptor antagonist cis-flupenthixol (FLU) into the medial PFC in the conflict test, and in one of its variants, the extinction of conflict test. Although both APO and FLU decreased response rates during Reward components, responding in the Conflict components of both tests was differentially affected. APO infusions decreased Conflict responses, the effect being more pronounced in the extinction of conflict test. In contrast, infusions of FLU increased responding in the Conflict components. The respective pro- and anti-conflict effects of APO and FLU infusions are in favour of a direct involvement of prefrontal DA in anxiety-related behavioural responses.     

Indirect calorimetry in mechanically ventilated infants and children: accuracy of total daily energy expenditure with 2 hour measurements.

OBJECTIVE: To determine how accurately total daily energy expenditure can be estimated from measurement periods of less than 24 h in mechanically ventilated infants and children. DESIGN: Prospective study to validate a method to determine energy expenditure. SETTING: Pediatric intensive care unit of an university hospital. PATIENTS: Nineteen ventilated patients (age 3 weeks - 13 years) with a FiO(2)of less than 60% and tube leakage < 10% (the difference between inspiratory and expiratory tidal volume measured by the ventilator). Separately, in five patients with varying tube leakage (2-59%) the influence of tube leakage on measured energy expenditure was determined. MEASUREMENT: Energy expenditure was measured by indirect calorimetry. Total daily energy expenditure measurements for 24 h were compared with 2 h energy expenditure measurements. The influence of body temperature on measured energy expenditure was determined. RESULTS: The mean coefficient of variation among 2 hour periods of measured energy expenditure was 6% (range 2-11%) compared with total daily energy expenditure measurements. The influence of body temperature revealed an increase of 6% of energy expenditure/ degrees C. An increased tube leakage influenced the energy expenditure measurements significantly (P< 0. 001). CONCLUSION: In a clinical situation in patients with a tube leakage < 10% total daily energy expenditure can be estimated from a 2 h measurement period.     

Characterization of the procoagulant chain derived from human high molecular weight kininogen (Fitzgerald factor) by human tissue kallikrein

Human high molecular weight kininogen (HMWK), a single-chain protein with mol wt 120,000, is cleaved by human urinary kallikrein (HUK) to release kinin from within a disulfide loop and form a two-chain protein that retains all the procoagulant activity of the native molecule. Cleavage of HMWK by HUK is associated with a reduction in size to mol wt 115,000, as assessed by SDS-PAGE of unreduced protein, whereas the two chains of the reduced protein present together as a single broad band with mol wt 64,000. The 64,000 chain with procoagulant activity was chromatographically separated from the nonfunctional chain of similar size. The homogeneous procoagulant chain had an amino acid composition similar to that of smaller procoagulant ("light") chains isolated by others upon cleavage of HMWK with plasma kallikrein and elicited an antiserum that was monospecific by Ouchterlony analysis and inhibited the procoagulant function of HMWK. Thus, the limited proteolysis of HMWK by HUK has permitted, for the first time, the isolation of a stable procoagulant chain that is equal in size to the nonfunctional chain. The common terminology of "heavy" and "light" chain for kinin-free kininogen obtained with plasma kallikrein reflects the continued degradation of the procoagulant carboxyterminal chain and is not appropriate for the initial two-chain product formed when kinin is released from HMWK. It is proposed that the initial cleavage products of HMWK be designated the A-chain, the B-fragment, and the C- chain, representing the amino-terminal chain, the released vasoactive peptide containing the bradykinin sequence, and the carboxy-terminal procoagulant chain, respectively. Thus, intact HMWK would contain, in sequence, A, B, and C regions.     

Fractures of the distal forearm. Which therapy is indicated when?

Every 15th case of a bone fracture in patients aged more than 65 years concerns the distal radius in Germany. This means the second rank of all geriatric fractures following fractures of the hip. According to the approved and increased apply of operative stabilisation there are arising more and more reports upon poor results of nonsurgical treatment. Especially in older patients the main reason for the discontented outcome of conservative management is osteoporosis, which is an affirmative circumstance for the genesis of fracture but also for secondary mal-aligment of comminuted thin cortical walls and crushed porotic cancellous bone. The rational of this perception is either filling artificial bonelike tissue--avoiding the need of harvest cancellous bone graft from a second surgical site--into the resultant cavity following reduction, or supplementary trans-styloidal or intrafocal K-wiring until remodeling is obtained within an average of 10 weeks. Both arrangements should be secured in addition with a trans-articular external fixation. According to a literature review and our own experiences of 92 follow up cases of distal radius fractures in patients who were older than 65 years this procedure seems to be superior at present for A-2, A-3 and most cases of type-C fractures of the distal radius, despite the disadvantage of joint immobilisation for about 5 weeks. Type B-fractures, however, should be provided better with an internal fixation. Sudeck's algodystrophia is the mostly serious complication of the distal radius fracture and its treatment in older patients. Recognising punctually neurovegetative stimulated patients, treat them cautiously and coming in on their special situation is usually the best way to reduce this risk. To pay attention to the topography of the nerves during the application of the pins and to act at the first signs of complications immediately is also very important. We examined 92 patients who were older than 65 years with a fracture of the distal end of the radius in a follow up study. In this group we treated 62 distal radius fractures of the type A and C of the AO classification with an trans-articular external fixateur and with supplementary measures if necessary. Additionally we filled the bone cavity with an artificial bone graft (Endobon) following closed reduction in 32 cases, 12 times a complementary K-wiring was added and in 8 cases the external fixateur was combined with both. Sudeck's disease appeared in 1.1% of all cases. In 5 cases we recorded complications with an obligation to treatment as well. Lesion of the superficial branch of the radial nerve were noted in 2 cases (2.1%), as far as we extended the surgical approach for the pin application. Technical problems from the site of the external fixateur appeared in 3 cases, two of them could be attributed to an infirmity of the fixateurs ball joints which is now eliminated by the producer. 4 patients with a type-B fracture was provided by plating, additionally 4 patients with a type-C fracture because of non-compliance. The external fixateur is an essential part of a differentiated treatment with reference to the several types of distal radius fractures in older patients.     

Risk factors for respiratory syncytial virus associated apnoea

Respiratory syncytial virus (RSV) infections are characterized by upper or lower respiratory tract symptoms including bronchiolitis and pneumonia. Apnoea may be the first sign of disease in children with RSV infection. The aims of this study were the identification of independent risk factors for RSV associated apnoea and the prediction of the risk for mechanical ventilation in children with RSV associated apnoea. Medical records of children younger than 12 months of age admitted with RSV infection between 1992 and 1995 to the Sophia Children's Hospital, were reviewed. Demographic parameters, clinical features and laboratory parameters (SaO₂, pCO₂ and pH) were obtained upon admission and during hospitalization. Children with and without apnoea were compared using univariate and multivariate logistic and linear regression analysis. One hundred and eighty-five patients with RSV infection were admitted of whom 38 (21%) presented with apnoea. Patients with apnoea were significantly younger, had a significantly lower temperature, higher pCO₂ and lower pH and had on chest radiographs also more signs of atelectasis. The number of patients admitted to the ICU because of mechanical ventilation and oxygen administration was significantly higher in children with RSV associated apnoea. Apnoea at admission was a strong predictor for recurrent apnoea. The relative risk for mechanical ventilation increased with the number of episodes of apnoea: 2.4 (95% CI 0.8 – 6.6) in children with one episode of apnoea (at admission) versus 6.5 (95% CI 3.3 – 12.9) in children with recurrent episodes of apnoea. Conclusions Age below 2 months is the strongest independent risk factor for RSV associated apnoea. Apnoea at admission increases the risk for recurrent apnoea. The risk for mechanical ventilation significantly increases in children who suffer from recurrent apnoea. Received: 12 May 1997 / Accepted in revised form: 22 August 1997