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Biomedical subjects

P Meyer

Publications and source records attributed to P Meyer.

At least 55 records · Page 3Linked to original sources
PubMed2002

[Cardiac arrest in a traumatized child from an unusual cause: atlanto-occipital luxation].

We report the case of a trauma child who developed a cardiac arrest due to atlanto-occipital luxation of the cervical spine. The occurrence of a rapidly reversible cardiac arrest in a trauma patient should alert physicians about cervical trauma. Adequate resuscitation of these patients require endotracheal intubation with concomitant full immobilisation of the cervical spine, plasma expansion to prevent arterial hypotension and immobilisation of the cervical spine during transport. Thorough application of these resuscitation techniques should increase the survival rate on admission to trauma centres of paediatric patients presenting with such a severe condition. Nevertheless, atlanto-occipital luxation is a major cause of paediatric cervical trauma mortality and our patient did not survive this condition.

Atlanto-Occipital Joint↗
PubMed2002

[Severe head injuries in the young child: early management].

The initial management of severely head-injured patients, including infants and children, is aimed at preventing and treating secondary brain damage, which mainly result from systemic insults (hypoxaemia, hypercarbia, arterial hypotension). Orotracheal intubation, followed by continuous sedation-analgesia, is mandatory when the Glasgow Coma Scale score (GCS) is less than or equal to 8 (crush induction is recommended). The goal of mechanical ventilation is to maintain normoxaemia and normocarbia. Moreover, the maintenance of an optimal cerebral perfusion pressure, usually 50 mmHg in infants, requires volume loading (isotonic fluids and colloids), and catecholamines if arterial hypotension persists. Intravenous mannitol is used only in case of life threatening intracranial hypertension, keeping in mind the potential for aggravating an hypovolaemia. Cerebral tomodensitometry is the most relevant imaging procedure for diagnosing surgical brain lesion. However, it should be noted, that severe head trauma is frequently associated with extra-cranial traumatic injuries, which may be responsible for (avoidable) deaths if the diagnosis is not made or delayed. Therefore, infants and small children presenting with severe head trauma should be considered as multiple injured and treated accordingly. Adequate initial management of severely head-injured children may participate to improved neurological outcome.

Child↗
PubMed2002

[Anesthetic management for craniosynostosis].

Surgical procedures for correction of craniosynostosis are performed in young infants with a small blood volume and represent major surgery with extensive blood loss. An accurate determination and a precise restoration of blood losses represent the major concern for the anaesthetist during this surgery. The preoperative assessment of these patients is usually simple, except in the cases where the craniosynostosis is associated with other congenital malformations. The anaesthetist should keep in mind that intracranial hypertension may be associated with craniosysnostosis, which modify the anaesthetic management, especially the induction of anaesthesia. Even though the psychological impact of a craniosynostosis should be taken into consideration, surgery is most often indicated for functional considerations, therefore parents should be informed of the risks related to the procedure. During the postoperative period the major concerns are related to the possibility of a persistent bleeding, which usually decreases and disappears over the first 12 hours.

Anesthesia↗
PubMed2002

[Anesthesia-resuscitation for intracranial expansive processes in children].

The most frequent space-occupying cerebral lesions in children are brain tumors, mostly posterior fossa tumors and haematoma resulting from arteriovenous malformation rupture. They result in intracranial hypertension, directly or by compression of the cerebrospinal fluid pathway resulting in hydrocephalus. Their localization and compressive effects are responsible for specific neurological deficits and general problems. Posterior fossa lesions carry a high risk of obstructive hydrocephalus, cranial nerves palsy and brain stem compression, pituitary and chiasmatic tumors a risk of blindness, pituitary deficiency and diabetes insipidus, and cortical tumors a risk of motor deficit and epilepsy. All these parameters must be analyzed before choosing anaesthetic protocols, and surgical techniques. In the presence of life-threatening intracranial hypertension, emergency anaesthetic induction, tracheal intubation and ventilation are life-saving. The specific treatment consists in either hydrocephalus derivation, initial medical treatment with osmotherapy, or rarely surgical removal. In other situations, surgical process requires a highly deep, stable anaesthesia with perfect control of cerebral haemodynamics. Surgical positioning is complex for these long lasting procedures and carries specific risks. The most common is venous air embolism in the sitting position that must be prevented by the use of specific measures. In the postoperative period, the risk of neurological and general complications commands close surveillance, fast track extubation must be adapted on an individual basis.

Anesthesia↗
PubMed2002

Analysis of the two common alpha-1-antitrypsin deficiency alleles PiMS and PiMZ as modifiers of Pseudomonas aeruginosa susceptibility in cystic fibrosis.

Lung disease is the direct cause of death in more than 90% of cystic fibrosis (CF) patients. Proteinase-antiproteinase imbalances are common in CF and alpha-1-antitrypsin (AAT) deficiency. We investigated the hypothesis that the AAT deficiency alleles PiS and PiZ contribute to pulmonary prognosis in CF. Two hundred and sixty-nine CF patients from Southern Germany were included in this study. The serum concentrations of AAT and C-reactive protein (CRP) were determined by nephelometry, and patients were screened by polymerase chain reaction (PCR) and restriction enzyme digest for the common AAT deficiency alleles PiS and PiZ. The onset of chronic bacterial colonization by Pseudomonas aeruginosa (Pae) was correlated with the AAT phenotypes PiMM, PiMS and PiMZ. Only three out of nine CF patients (33%) diagnosed with either PiMS or PiMZ had developed chronic Pae lung infection earlier in their lives. The remaining six patients showing a PiMS or PiMZ phenotype showed a later onset of chronic Pae lung infection. Our results indicate that PiMS and PiMZ are not associated with worse pulmonary prognosis in CF. These data need to be confirmed in studies with a much larger number of cases.

Alleles↗
PubMed2002

Prevalence of symptoms, sensitization to rats, and airborne exposure to major rat allergen (Rat n 1) and to endotoxin in rat-exposed workers: a cross-sectional study.

OBJECTIVE: To analyse the relation between airborne exposure to major rat allergen and to endotoxins in exclusively rat-exposed workers and the prevalence of rat-related symptoms and sensitization. METHODS: A total of 113 workers answered a standardized questionnaire on their atopy status, occupational exposure to rats, and possible work-related symptoms. Specific IgE against rat urinary proteins (RUP) was measured for 73 subjects. Individual airborne exposure to Rat n 1 and endotoxin were determined with static (n = 256) samplings. Rat n 1 was measured with enzyme-linked immunosorbent assay (ELISA) and endotoxin by the Limulus method. RESULTS: Forty-four of 113 subjects (38.9%) reported at least one rat-related symptom: asthma (4.4%), rhinitis (34%) and conjunctivitis (16%). Twelve per cent were sensitized to RUP (specific IgE > 0.35 KU/L). But only 30.8% of all symptomatic subjects were sensitized to rat allergens. Airborne Rat n 1 levels were not related to symptoms in workers. Symptomatic patients not sensitized to rats were exposed to higher endotoxin levels, but airborne exposure to endotoxins did not significantly protect against or increase sensitization to RUP or rat-related symptoms. CONCLUSION: Most symptomatic workers were not sensitized to rat allergen; but no significant relation between rat-related symptoms and endotoxin levels was found. This suggests that more studies are needed to determine causes other than rat allergens or endotoxins that may be responsible for symptoms in rat-exposed workers.

Adult↗
PubMed2002

Melatonin MT-1-receptor immunoreactivity in the human eye.

AIM: To examine the distribution of melatonin 1a (MT1) receptors in the human eye. METHODS: Seven normal human eyes were examined by immunohistochemical staining of paraffin sections, using an anti-MT1 primary antibody and an ABC detection system. RESULTS: MT1 receptor immunoreactivity (MT1-IR) was detected primarily in the inner segments of rods and cones and in retinal ganglion cells. In addition, MT1-IR was present in the adventitia of retinal arteries and veins, including the papillary region, but absent in ciliary and choroidal vessels. Mild staining of corneal endothelial cells and keratocytes was observed in all but two eyes. CONCLUSION: MT1-IR is present in various ocular tissues with the highest density in photoreceptor cells and ganglion cells. The physiological function of these receptors deserves further investigation.

Aged↗
PubMed2002

In vitro isolation of equine piroplasms derived from Cape Mountain zebra (Equus zebra zebra) in South Africa.

Twenty blood samples of zebras (Equus zebra zebra) from the Karoo National Park and the Bontebok National Park in South Africa, all seropositive for Theileria equi, were subjected to in vitro culture to identify carrier animals and to isolate the parasites. Sixteen animals had a detectable parasitaemia in Giemsa-stained blood smears examined before culture initiation, the remaining four animals were identified as T. equi carriers by in vitro culture. Cultures were initiated either in an oxygen-reduced gas mixture or in a 5% CO2-in-air atmosphere. Out of the 20 blood samples, 12 cultures of T. equi and two cultures of T. equi mixed with Babesia caballi were established. None of the four animals seropositive for B. caballi could be identified as carrier animals, whereas two seronegative samples became culture-positive for B. caballi.

Animals↗
PubMed2001

Thalidomide produces transfusion independence in long-standing refractory anemias of patients with myelodysplastic syndromes.

Thalidomide was administered to 83 patients with myelodysplastic syndrome (MDS), starting at 100 mg by mouth daily and increasing to 400 mg as tolerated. Thirty-two patients stopped therapy before 12 weeks (minimum period for response evaluation), and 51 completed 12 weeks of therapy. International Working Group response criteria for MDS were used to evaluate responses. Intent-to-treat (ITT) analysis classified all off-study patients as nonresponders. Off-study patients belonged to a higher risk category (P =.002) and had a higher percentage of blasts in their pretherapy bone marrow than patients who completed 12 weeks of therapy (P =.003). No cytogenetic or complete responses were seen, but 16 patients showed hematologic improvement, with 10 previously transfusion-dependent patients becoming transfusion independent. Responders had lower pretherapy blasts (P =.016), a lower duration of pretherapy platelet transfusions (P =.013), and higher pretherapy platelets (P =.003). Among responders, 9 had refractory anemia (RA); 5 had RA with ringed sideroblasts; and 2 had RA with excess blasts. By ITT analysis, 19% of patients (16 of 83) responded, and when only evaluable patients were analyzed, 31% (16 of 51) responded. It was concluded that thalidomide, as a single agent, is effective in improving cytopenias of some MDS patients, especially those who present without excess blasts. (Blood. 2001;98:958-965)

Aged↗
PubMed2001

Chemical rescue of phosphoryl transfer in a cavity mutant: a cautionary tale for site-directed mutagenesis.

We have explored the ability of a nucleoside diphosphate kinase (NDPK) mutant in which the nucleophilic histidine has been replaced by glycine (H122G) to transfer phosphate from ATP to alcohols of varying pK(a), size, shape, and polarity. This cavity mutant does indeed act as a primitive alcohol kinase. The rate of its phosphoryl transfer to alcohols varies considerably, with values spanning a DeltaDeltaG(double dagger) range of 4 kcal/mol, whereas the alcohols have very similar intrinsic reactivities. Analysis of these results suggests that the ability to carry out phosphoryl transfer within the cavity is not a simple function of being small enough to enter the cavity, but rather is a complex function of steric, solvation, entropic, van der Waals packing, and electrostatic properties of the alcohol. In addition, large differences are observed between the reactivities of alcohols within the nucleophile cavity of H122G and the reactivities of the same alcohols within the nucleophile cavity of H122A, a mutant NDPK that differs from H122G by a single methyl group within the cavity. The crystal structures of the two cavity mutants are very similar to one another and to wild-type NDPK, providing no evidence for a structurally perturbed active site. The differences in reactivity between the two mutant proteins illustrate a fundamental limitation of energetic analysis from site-directed mutagenesis: although removal of a side chain is generally considered to be a conservative change, the energetic effects of any given mutation are inextricably linked to the molecular properties of the created cavity and the surrounding protein environment.

Adenosine Triphosphate↗
PubMed2001

[Quantitative studies of lysozyme and phosphohexose isomerase enzymes in mixed saliva in oral squamous epithelial carcinoma].

BACKGROUND: In connection with quantitative sialochemical investigations in mixed saliva from patients with oral squamous cell carcinoma (OPC), the enzymes phosphohexoseisomerase (PHI) and lysozyme (Ly) were investigated. The glycolytic enzyme PHI recently became interesting as a tumor marker. Lysozyme represents the main enzyme of the nonspecific salivary immune defense. PATIENTS AND METHODS: The enzyme concentrations were specified in 25 men with OPC and in a control group of 20 healthy men of comparable age. RESULTS AND CONCLUSIONS: In the mixed saliva of the OPC patients, the PHI concentration was significantly diminished according to the Mann-Whitney-Wilcoxon test compared to the control group (p = 0.022). The lysozyme concentration, however, significantly increased (p = 0.011). These results prove serious sialochemical alterations in mixed saliva of OPC patients. They extend our former studies on kallikrein in glandular mixed saliva, but at present only have a descriptive character. Further pathobiochemical investigations on this subject should be carried out.

Adult↗
PubMed2001

Validity of applying TRISS analysis to paediatric blunt trauma patients managed in a French paediatric level I trauma centre.

OBJECTIVE: Using a weighted combination of the Revised Trauma Score (RTS), the Injury Severity Score (ISS), the type of injury (blunt or penetrating) and patient age, the TRISS method is used to calculate the probability of survival (ps) in trauma patients. The goal of this study was to compare the ability of the American Major Trauma Outcome Study (MTOS) norm for adult blunt trauma patients (ADULT) and the specific norm for paediatric patients (PED) to estimate the ps of injured children using TRISS methodology. DESIGN: Retrospective analysis using a paediatric trauma patient database. SETTING: A French level 1 paediatric trauma centre. PATIENTS: Four hundred seven consecutive paediatric blunt trauma patients, treated over a 3-year period. MEASUREMENTS: The observed and expected survivals were compared, using the M, W and Z scores, with both ADULT and PED. The W score is the number of survivors more or less than expected from the MTOS predictions for 100 patients. A Z score, which measures the significance of W, between -1.96 and +1.96, indicates no significant difference between observed and expected survivors. A value of M less than 0.88 indicates a disparity in the severity match between the study group and the MTOS group. We calculated the standardised W score (Ws), which represents the W score that would have been observed if the case mix of severity was identical to that of the MTOS group. Accordingly, a standardised Z score (Zs) was also calculated. In addition, we calculated the area under the receiver operating curve (aROC) using both norms, while calibration was also assessed by calculation of the Hosmer-Lemeshow goodness-of-fit tests. RESULTS: Using PED, the number of actual survivors (n = 364) was not significantly different from the MTOS (n = 358). The value of M, 0.65, indicated a disparity in the severity match between the study group and the MTOS group, due to a higher proportion of patients with lower ps (TRISS < 0.95, 52 vs 27%). We was +1.06% (95% confidence interval -0.34 to 2.08) and Zs was 1.48, indicating no significant difference from the MTOS. Using ADULT, the number of observed survivors (n = 364) was significantly higher than that expected (n = 354), with a W score of +2.70% (Z = +1.98, p < 0.05). There was a disparity in the severity match (M = 0.67) between the study group and the MTOS group, due to a higher proportion of patients with lower ps. Ws was +1.32% (95% confidence interval -0.12 to 2.37) and Zs = +1.79 (NS), indicating no significant difference from the MTOS. The Hosmer-Lemeshow statistics indicated that ADULT (Cg = 7.24, p = 0.51; Hg = 4.45, p = 0.81) and PED (Cg = 6.08, p = 0.64; Hg = 3.55, p = 0.90) provided sufficient goodness-of-fit. There was no significant difference in the aROC of the TRISS between the two norms (0.935 +/- 0.050 vs 0.936 +/- 0.050; NS). CONCLUSION: Both adult and paediatric norms were equally good predictors of the probability of survival of injured children, provided that Ws and Zs are used when there is a disparity in the severity match between the study group and the MTOS group.

Adolescent↗
PubMed2001

[Acute hemolysis following perioperative blood salvage in chldren operated for the surgical correction of craniosynostosis].

We report the case of a 6-month-old child, who suffered from acute haemolysis following transfusion of salvaged blood. This complication, of favourable outcome, was related to the accidental aspiration of benzalkonium chloride into the cell saver. This case emphasizes that any adjunction of antiseptic solution is contraindicated during blood saving. The use of a cell saver must be associated with written protocols, describing clearly the contraindications, precautions of use, and the different steps of use of this method of autologous blood transfusion.

Acute Disease↗
PubMed2001

[Pulmonary embolism in sclerotherapy for a venous malformation in a child under general anesthesia].

We report a case of pulmonary embolism associated with percutaneous sclerotherapy (absolute ethanol: 0.5 mL.kg-1) of a venous angioma, performed under general anaesthesia in a 13 year-old child. The diagnosis of pulmonary embolism, suspected on the clinical setting and symptoms, was supported by the pulmonary scintigraphy obtained 4 hours later, showing 3 minimal pulmonary defects. The outcome was rapidly favourable without sequelae under heparin administration and the pulmonary scintigraphy, performed on day 7, was normal. The role of absolute ethanol, for explaining the apparent contrast between the severity of the symptoms and the minimal obstruction noted on pulmonary scintigraphy is discussed. Also discussed are the prophylactic and curative therapeutic issues of this severe complication.

Anesthesia, General↗