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Biomedical subjects

C Meyer

Publications and source records attributed to C Meyer.

At least 433 records · Page 24Linked to original sources
PubMed1989

[What is new in nasopharyngeal video fiber optic endoscopy in the diagnosis of snoring and patients with obstructive apnea?].

Videoendoscopy of the oropharynx was performed in 57 patients with habitual snoring and obstructive sleep apnoea syndrome. Endoscopy was done in waking supine subjects relaxed and during voluntary snoring, Esmarch's and modified Müller's manoeuvre. Evaluation of results for the first time was semiquantitative. Statistical analysis showed significant correlations (p less than 0.004) between movements of the base of the tongue and the modified Müller's manoeuvre. For the first time it could be shown that the dynamic changes in the pharyngeal walls during voluntary snoring are identical with those in the modified Müller's manoeuvre (p less than 0.006). Frame-by-frame analysis demonstrated epiglottic movements in the inspiratory cycle of snoring which result in a massive occlusion of the airway in 65% of our patients. Videoendoscopy is able to provide valuable information on anatomical details and potential obstructive sites but cannot predict the success of surgical interventions like UPPP. Videoendoscopy due to its high resolution in the time domain can demonstrate pathophysiological events which are otherwise inaccessible. For the experienced examiner videoendoscopy is a fast tool for obtaining live information on the surgical site.

Airway Obstruction↗
PubMed1989

Interaction of a nuclear location signal with isolated nuclear envelopes and identification of signal-binding proteins by photoaffinity labeling.

The nuclear envelope (NE) separates the two major compartments of eukaryotic cells, the nucleus and the cytoplasm. Recent studies suggest that the uptake of nuclear proteins into the nucleus is initiated by binding of nuclear location signals (NLSs) contained within these proteins to receptors in the NE, followed by translocation through the nuclear pore complex. To examine the binding step without interference from intranuclear events, we have used a system consisting of (i) purified rat liver NEs fixed onto glass slides and (ii) the prototype simian virus 40 large T antigen (SV40 T) NLS conjugated to nonnuclear carrier proteins, and we have visualized the receptor-ligand interaction by indirect immunofluorescence. In this system, incubation of isolated NEs with the wild-type SV40 T NLS conjugate with carrier proteins resulted in binding that was signal sequence-dependent, could be competitively blocked with excess conjugated and unconjugated wild-type peptide, did not require ATP, and was not affected by the transport-inhibiting lectin wheat germ agglutinin. In contrast, only minimal binding was observed with a mutant SV40 T NLS conjugate. These results are consistent with those obtained in other, more complex in vitro systems and suggest that binding of the SV40 T NLS is receptor-mediated. Binding is largely abolished by extraction of the NE with the nonionic detergent Triton X-100, suggesting that the receptor is soluble in detergent. We find in the Triton X-100 supernatant four major NLS-binding proteins with apparent molecular masses of 76, 67, 59, and 58 kDa by photoaffinity labeling with a highly specific crosslinker, azido-NLS. The reduced complexity of the system described here should be useful for the functional study of other potential NLSs for the identification and isolation of their binding sites and for the screening of antibodies raised against these binding sites.

Affinity Labels↗
PubMed1989

Fusicoccin-Binding Proteins in Arabidopsis thaliana (L.) Heynh. : Characterization, Solubilization, and Photoaffinity Labeling.

Using the novel radioligand, [(3)H]-9'-nor-fusicoccin-8'-alcohol, high affinity binding sites for fusicoccin were characterized in preparations from leaves of Arabidopsis thaliana (L.) Heynh. The binding site copartitioned with the plasmalemma marker, vanadate-sensitive K(+), Mg(2+)-ATPase, when microsomal fractions were further purified by aqueous two-phase partitioning in polyethylene glycol-dextran phase systems and sedimented at an equilibrium density of 1.17 grams per cubic centimeter in continuous sucrose density gradients, as did the ATPase marker. The binding of [(3)H]-9'-nor-fusicoccin-8'-alcohol was saturable and Scatchard analysis revealed a biphasic plot with two apparent dissociation constants (K(D)), K(D1) = 1.5 nanomolar and K(D2) = 42 nanomolar, for the radioligand. Binding was optimal at pH 6, thermolabile, and was reduced by 70% when the membrane vesicles were pretreated with trypsin. The data are consistent with the presence of one or several binding proteins for fusicoccin at the plasma membrane of A. thaliana. Binding of the radioligand was unaffected by pretreatment of the sites with various alkylating and reducing agents, but was reduced by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, diethylpyrocarbonate, chloramine T, and periodate. A number of detergents were tested to find optimum conditions for solubilization. Nonanoyl-N-methylglucamide (50 millimolar) solubilized 70% of the radioligand-binding protein complex in undissociated form. Photoaffinity labeling of membrane preparations with a tritiated azido analog of fusicoccin resulted in the labeling of a 34 +/- 1 kilodalton polypeptide. Labeling of this polypeptide, presumably the fusicoccin-binding protein, was severely reduced in the presence of unlabeled fusicoccin.

Journal Article↗
PubMed1989

[Perforations of the colon. Apropos of 74 cases].

74 colic perforations were surgically handled between 1975 and 1988. Among the non-traumatic perforations, which represent 74% of this series, 39 cases (71%) complicated the course of acute diverticulitis, 9 cases (15%) were due to cancers and 7 cases (13%) were of miscellaneous origin. Traumatic perforations (26%) were iatrogenically induced in 84% (16 cases). In 78% the perforation was located in the sigmoid or recto-sigmoid. The treatment consisted in performing either a diverting colostomy (30 cases--40%) or a colic resection (44 cases--60%) with or without immediate anastomosis (respectively 10 cases--13.5% and 34 cases--46%). The overall mortality was 10.8%, which referred to etiology, turns to be 15% (3/19 cases) in traumatic perforations, 13% (5/39 cases) in diverticulitis and 0% in cancer. Related to treatment, mortality reached 23% for derivation and drainage procedure and 2% for resection. Post-operative complications were respectively 10% and 47%. Among post operative complications (22 cases--29%) 11 patients were reoperated on with an additional mortality of 18%. These results give strong evidence to the reliability and value of urgent colic resection in perforated colon and enhance the necessity of undelayed operation.

Adolescent↗
PubMed1989

[Injuries of the spleen: conservative treatment or exeresis?].

The authors report their experience with splenic preservation in a series of 36 patients. 77 patients with splenic injury were seen during the period from 1982 to 1987. In 41 cases splenectomy had to be carried out. This was for splenic contusions secondary to road traffic accidents in 36 cases and iatrogenic per-operative lesions in 5 cases. Intra-omental splenic autotransplantation was performed in 4 cases. In 36 other patients, the spleen was able to be preserved. Hemostasis was fairly obtained using infra-red photocoagulation (24 cases), splenorrhaphy (8 cases), surrounding the spleen with a resorbable mesh (3 cases) or by partial splenectomy (1 case). Only 1 case of transient and moderate secondary hemorrhage was seen and did not require further surgery. The authors define the legitimacy of splenic preservation and its indications and also stress its limitations. They insist on the following contraindications: preexisting splenic disease, subject on anticoagulants, labile blood pressure, multiple intra-abdominal lesions, presence of intra-peritoneal infection, severe cranio-encephalic lesions, age over 70 years. Study of this series shows that conservative treatment is most often justified for splenic trauma. Nevertheless, in view of the real but rare risk of OPSI, it is better to have a correct splenectomy than an incorrectly preserved spleen.

Aged↗
PubMed1989

[Colonic occlusion. Apropos of a surgical series of 63 cases].

63 colonic occlusions were operated on from 1975 to 1988. Cancer and stenotic diverticular sigmoiditis were found to be the main causes of colonic obstruction in respectively 36 cases (55%) and 8 cases (13%). Other etiologies were represented by neoplasic gynecologic diseases (9.5%). The rectosigmoid was involved in 50% of the cases (31) while transverse colon and caecum were respectively concerned in 25% and 17%. The 2 main therapeutical procedures used were colic resection (35 cases-55%) with immediate anastomosis in 1 case out of 3 and derivation (26 cases 41%) mostly in the proper from of a colostomy (20 cases). Operation was undertaken during the first 48 hours in 65% of the cases. Death occurred in 8 patients (12.5%). Related to etiology the death rate was 11% in cancers and 25% in stenotic diverticulitis. Where linked to treatment this mortality rate reached 27% in derivations and 3% in colic resections. 38% of non lethal complications were recorded, two-third being due to the bad general conditions of the patients. Several times operations, such as first colostomy or resection without anastomosis, should remain the basic rule one should not depart from without great carefulness. However a new interesting trend toward one time surgery with intraoperative colonic lavage is taking shape.

Adolescent↗
PubMed1989

[Locoregional recurrence of breast cancer. Long-term course of 49 cases treated by excision and omentoplasty].

Extensive local recurrence of breast cancer may require wide parietal resection, demanding the use of other tissues to compensate for the loss of substance. We preferably resort to omentoplasty when the defect is larger than 300 cm2. A group of 49 patients with recurrence of the tumor in the breasts (treated with omentoplasty) has been studied, with special emphasis on long-term results. In our series, 86% of the patients were followed up for more than 4 years, with an actuarial survival rate of 46% after 7 years. It thus appears that this procedure can be advocated for slow-developing cancers, the local recurrence of which is extensive and usually isolate for various reasons (most often a deficient initial local treatment).

Aged↗
PubMed1989

[Therapy of headache].

Very little is known about the neural correlates of facial pain and headaches; diagnosis and treatment are for the most part clinically orientated. Of initial importance is the recognition of dangerous situations and the consequent appliance of additional methods of examination. The tension headache is taken as an example to show the principle aspects of therapy which also apply for the treatment of migraine. Pharmacological possibilities in acute and chronic circumstances are mentioned, in addition to the nonpharmacological alternatives. Particular emphasis is given to drug habituation, the significance of which has become increasingly recognized in recent years. The problems connected with the most common facial pains are discussed.

Analgesics↗
PubMed1989

[Current concepts of the treatment of cholelithiasis in aged patients].

Biliary lithiasis in elder patients is characterized by the physical defects usually present--therefore surgery is less mandated than endoscopic procedures or extra corporeal lithotripsy. However, if surgery is undertaken, then it should be carried out as completely as possible. In this paper, the authors emphasize the special aspects of its indications and technics--for more than any where else this surgery required perfection.

Aged↗
PubMed1988

Bioavailability of beta-carotene in humans.

Normal healthy volunteers were studied after they ingested various beta-carotene doses. Daily administration of 15 or 45 mg beta-carotene resulted in significant increase in plasma beta-carotene levels. The extent of increase and the pattern of plasma beta-carotene levels showed substantial interindividual variation. Absorption of beta-carotene was affected by dietary fat concentration. Individuals placed on a high-fat diet showed significant increases in plasma beta-carotene as compared with those placed on a low-fat diet. Pharmacological doses of beta-carotene (45 and 90 mg) were used in intermittent schedules (5-6 d intervals) without altering the steady state of beta-carotene plasma levels. Yellowing of the skin occasionally occurred during daily dosing with 45 mg beta-carotene without evidence of toxicity. The observed individual variation in bioavailability of beta-carotene raises questions regarding clinical use of this micronutrient. It appears that determination of target plasma beta-carotene concentrations is essential for effective use of this compound in prevention or treatment.

Adult↗
PubMed1988

The Effect of Adenine Nucleotides on Purified Phosphoenolpyruvate Carboxylase from the CAM Plant Crassula argentea.

The effects of adenine nucleotides on phosphoenolypyruvate carboxylase were investigated using purified enzyme from the CAM plant, Crassula argentea. At 1 millimolar total concentration and with limiting phosphoenolpyruvate, AMP had a stimulatory effect, lowering the K(m) for phosphoenolpyruvate, ADP caused less stimulation, and ATP decreased the activity by increasing the K(m) for phosphoenolpyruvate. Activation by AMP was not additive to the stimulation by glucose 6-phosphate. Furthermore, AMP increased the K(a) for glucose 6-phosphate. Inhibition by ATP was competitive with phosphoenolpyruvate. In support of the kinetic data, fluorescence binding studies indicated that ATP had a stronger effect than AMP on phosphoenolpyruvate binding, while AMP was more efficient in reducing glucose 6-phosphate binding. As free Mg(2+) was held constant and saturating, these effects cannot be ascribed to Mg(2+) chelation. Accordingly, the enzyme response to the adenylate energy charge was basically of the "R" type (involving enzymes of ATP regenerating sequences) according to D. E. Atkinson's (1968 Biochemistry 7: 4030-4034) concept of energy charge regulation. The effect of energy charge was abolished by 1 millimolar glucose 6-phosphate. Levels of glucose 6-phosphate and of other putative regulatory compounds of phosphoenolpyruvate carboxylase were determined in total leaf extracts during a day-night cycle. The level of glucose 6-phosphate rose at night and dropped sharply during the day. Such a decrease in glucose 6-phosphate concentration could permit an increased control of phosphoenolpyruvate carboxylase by energy charge during the day.

Journal Article↗
PubMed1988

Critical choices.

The burglar's request, "your money or your life," follows our rescue imperative made possible with technological advances in medicine. We can now keep extremely sick and dying patients alive at great cost. Often, we spend large amounts of money on extraordinary treatment and the patient still dies. The Rev. Meyer examines ethical considerations stemming from our high tech capabilities.

Ethics↗
PubMed1988

Alterations of melatonin secretion in atopic eczema.

The circadian rhythm of melatonin secretion of the pineal gland can be disturbed in a variety of clinical conditions and diseases including some psychic disorders. To study the rhythmic behaviour of melatonin secretion in atopic eczema (AE), melatonin serum levels were measured every 2 h, starting at 8 a.m. in 18 patients suffering from severe AE. In 6 patients exhibiting low serum levels of melatonin, the circadian melatonin rhythm was found to be abolished. In 8 patients a diminished nocturnal melatonin increase was observed compared with the controls (n = 40). Only 4 patients showed a normal secretion pattern of melatonin. The results provide some evidence of a dysfunction of the pineal gland in AE, possibly due to a partially reduced activity of the sympathetic nervous system being involved in the control of melatonin secretion.

Adolescent↗
PubMed1988

[Gastroesophageal reflux in asthmatic and chronic bronchitis patients].

To determine the relationship between gastroesophageal (GE) reflux and pulmonary disease, we studied 21 asthmatics, 30 chronic bronchitics, 6 patients with GE reflux and no pulmonary symptoms, and 10 control subjects; GE reflux was diagnosed by pH monitoring and GE scintiscanning. Frequency of GE reflux in the asthmatics was 57%; in chronic bronchitis it was 56%. Pulmonary function tests did not show any differences between patients with or without reflux. The GE reflux episodes were more numerous but shorter in asthmatics than in chronic bronchitis. Patients with digestive symptoms alone were no different from chronic bronchitis with respect to reflux. The mechanism whereby reflux triggers pulmonary problems was investigated using the following 2 tests: scintiscan for pulmonary aspiration, and esophageal acid infusion (0.1N HCI). Six pulmonary aspirations were detected. Only asthmatics, with or without reflux, showed any significant variations in maximal expiratory flow at 50% and 25% of VC after HCI infusion. Thus, our results show that asthmatics differ from bronchitis patients by the characteristics of their reflux.

Adult↗
PubMed1988

[The financing of medico-technical activities. The example of a scanner in France (1986)].

To analyse the french methods for financing technical-medical activities as CT scanners, and to assess if they can face, or not, the management constraints of such activities a financial simulation has been executed. First, current expenditures are totalized (including depreciations and financial charges) with variations according to the number of examinations per year. Costs are classified especially according to fixed and variable charges: the weight of fixed charges, especially equipment charges, is the most significant. It's very high in yearly expenditures. Most, that involves a very fast decreasing cost with increasing number of procedures. Second, consequences of such accounts are analyzed: on private CT scanners, Payed with a charge per examination whatever would be the factor's cost; on public CT scanners, payed with an annual allowance; in this case charges equal receipts whatever would be the cost for a procedure. Third, a break point is defined; either the annual activity is higher: there would be an excedent; either it is lower: there would be a deficit. Then, those results are reported to CT-scanners activity's data in France (1986). After all, we discuss about financing systems themselves, and suggest a few hypothesis to explain those desadjustments between charges and their financing way.

Financial Management↗
PubMed1988

Study of living single cells in culture: automated recognition of cell behavior.

An automated system capable of analyzing the behavior, in real time, of single living cells in culture, in a noninvasive and nondestructive way, has been developed. A large number of cell positions in single culture dishes were recorded using a computer controlled, robotized microscope. During subsequent observations, binary images obtained from video image analysis of the microscope visual field allowed the identification of the recorded cells. These cells could be revisited automatically every few minutes. Long-term studies of the behavior of cells make possible the analysis of cellular locomotary and mitotic activities as well as determination of cell shape (chosen from a defined library) for several hours or days in a fully automated way with observations spaced up to 30 minutes. Short-term studies of the behavior of cells permit the study, in a semiautomatic way, of acute effects of drugs (5 to 15 minutes) on changes of surface area and length of cells.

Animals↗