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Biomedical subjects

N Muller

Publications and source records attributed to N Muller.

54 records · Page 3Linked to original sources
PubMed1990

[Morphological and functional characteristics of the palatal mucosa and the palatine glands].

Histologic findings of the palatal mucosa and the palatal glands of 73 patients with and without upper dentures were compared with distinctive marks, complaints and clinical diagnoses as well as with the secretion of the minor salivary glands. Patients complaining of oral burns show the same rate of patho-histologic findings as those without any complaints. Inflammation and atrophic reactions of the palatal mucosa and the palatal glands do not reduce the secretion rate of the minor glands. In these cases, however, considerable changes of the quotient exist between sodium and potassium ions of the palatal saliva secretion. Signs of inflammation of the palatal tissues were seen more frequently in full denture wearers and especially in those wearing upper dentures during day and night. Causative factors of denture incompatibility are discussed.

Burning Mouth Syndrome↗
PubMed1987

Airway involvement in ulcerative colitis.

Two patients with ulcerative colitis developed progressive obstructive pulmonary disease. In one, the abnormality was a sclerosing peribronchiolitis confined to small airways, while the other demonstrated a large airway fibrotic obliterative bronchitis. A review of airway involvement in ulcerative colitis and a discussion of the possible similarity to another extraintestinal manifestation of ulcerative colitis, sclerosing cholangitis, are presented.

Adult↗
PubMed1986

When is a trifluoromethyl group more lipophilic than a methyl group? Partition coefficients and selected chemical shifts of aliphatic alcohols and trifluoroalcohols.

Octanol-water partition coefficients were determined for 12 trifluoromethylated aliphatic alcohols and their unfluorinated counterparts. The latter values were derived from measurements using the benzyl alcohol-water solvent system after developing an appropriate correlation equation. Incidentally, an empirical equation was found which allows the partition coefficient of an unsubstituted alcohol to be estimated given the molecular formula and boiling point. Trifluorination strongly enhances lipophilicity only when the trifluoromethyl group is in the alpha-position. The enhancement is barely measurable for the beta- and gamma-(trifluoromethyl) alcohols, while the delta- and epsilon-(trifluoromethyl) compounds are considerably more hydrophilic than their parent compounds. Chemical shift comparisons suggest that the changes in relative lipophilicity are controlled primarily by the inductive effect of the trifluoromethyl group on the acidity-basicity of the hydroxyl group. New synthetic procedures for obtaining some of the alcohols are presented.

Alcohols↗
PubMed1986

Clinical and laboratory evaluation of cytomegalovirus-induced mononucleosis in previously healthy individuals. Report of 82 cases.

The present report describes the clinical and laboratory profile of 82 previously healthy individuals who developed cytomegalovirus (CMV)-induced mononucleosis. Many of these patients posed initial diagnostic problems and were hospitalized with diagnoses such as fever of undetermined origin, active viral hepatitis, acute leukemia, probable systemic lupus erythematosus, autoimmune hemolytic anemia, and severe pancytopenia. These patients underwent a variety of diagnostic biopsies, including liver biopsies (6) and bone marrow aspirations (9). Four patients had exploratory laparotomies, 1 for a ruptured spleen, and another had a splenectomy following an erroneous initial diagnosis of agnogenic myeloid metaplasia. There was no apparent clinical response to a short course of steroid therapy in 3 of 5 cases and acyclovir in another. The vast majority of these patients demonstrated infectious mononucleosis-type reactive blood smears, negative heterophil antibody studies, mildly or moderately elevated aspartate aminotransferase activity, and evidence for subclinical hemolysis on serial specimens. The peak serum bilirubin levels were above 2.0 mg/dl in only 2 of 71 cases tested, both of the latter patients having significant hemolysis (hemoglobin values 8.6-9.3 g/dl). The CMV-IgM test had a high sensitivity for detection of CMV macroglobulins (positive in 81 of 82 cases). In contrast, complement-fixing antibodies to CMV showed diagnostic four-fold titer changes in only 39/82 cases (47.6%). Despite its great sensitivity, the CMV-IgM test is limited by a one-way crossreaction of acute Epstein-Barr virus (EBV)-IM sera and spurious positive reactions in some sera due to the presence of rheumatoid factors. Based on EBV-specific serologic studies, the 82 patients with CMV-IM could be divided into 4 groups: 3 patients without antibodies to EBV; 2) 69 patients with uncomplicated serologic data indicative of long-past EBV infections; (3) 6 patients with unusual antibody profiles, e.g., anti-D responses; and (4) 5 patients, including 1 originally susceptible to EBV, with apparent dual CMV/EBV infections. At the conclusion of our study, final diagnoses and initial hematologic data were correlated in 750 cases in which CMV macroglobulins were searched for. The vast majority of patients with active CMV infections initially demonstrated either markedly or moderately reactive peripheral blood smears. These data support our impression that diagnostic tests for CMV, as well as for EBV, are seldom indicated in symptomatic previously healthy patients whose blood smears during the acute phase (first several weeks) of their illnesses are either nonreactive or minimally reactive.

Adolescent↗
PubMed1986

MRI of pulmonary airspace disease: experimental model and preliminary clinical results.

To evaluate the potential of MRI for differentiating the various causes of pulmonary consolidation, 16 patients with known airspace diseases were imaged, and T1 and T2 values were determined. Substantial overlap was encountered between different diagnostic groups of T1 and T2 mapping, although alveolar proteinosis was notable for its low T1 value. In addition, a gelatin phantom simulating consolidation with varying degrees of residual aeration was constructed and tested, demonstrating that the degree of aeration did not influence the T1 and T2 values measured.

Diagnosis, Differential↗
PubMed1981

Measurement of ventilation in children using the respiratory inductive plethysmograph.

A new technique to measure ventilation, based on the separate contributions of rib cage and abdomen to tidal volume, the respiratory inductive plethysmograph was evaluated in 20 healthy children. The accuracy of the method was determined by simultaneously measuring tidal volume with a pneumotachograph in the standing, sitting, supine, left lateral decubitus, and prone postures. Comparison of these two techniques showed mean correlation coefficients greater than 0.96, mean slopes between 0.98 and 1.11, and mean SEE of less than 8% in all postures studied. Breathing through a mouthpiece connected to a pneumotachograph resulted in a substantial change in the pattern of breathing and a mean increase in tidal volume of 32% (P less than 0.05). In the standing and sitting postures, rib cage contribution to tidal volume was predominant (greater than 65%) whereas in the recumbent postures abdominal contribution was predominant (greater than 61%). We conclude that the RIP is an accurate means of measuring ventilation in children and that it avoids the artifacts caused by using a conventional respiratory measuring apparatus.

Abdomen↗
PubMed1981

Tonic inspiratory muscle activity as a cause of hyperinflation in asthma.

We studied tonic activity of the inspiratory muscles during exacerbation of asthma in five female and two male patients. Exacerbation was provoked by withholding bronchodilatory medication for 12 h prior to the study. Thoracic gas volume (TGV) at the end of resting expiration was determined before and after albuterol (salbutamol) inhalation with a body plethysmograph. Intercostal muscle electromyogram (EMG) was recorded with surface electrodes and diaphragmatic EMG with esophageal electrodes. Tonic activity was defined as electrical activity in the EMG present throughout expiration. After salbutamol the TGV decreased 13.4 +/- 2.9% (mean +/- SE) (P less than 0.01). This decrease in TGV was accompanied by a proportional reduction in tonic intercostal (r = 0.78, P less than 0.05) and diaphragmatic activity (r = 0.84, P less than 0.05). These findings suggest that the hyperinflation present during exacerbation of asthma is at least in part due to active inspiratory muscle activity present throughout expiration.

Adult↗
PubMed1980

Tonic inspiratory muscle activity as a cause of hyperinflation in histamine-induced asthma.

We studied the change in tonic activity of the inspiratory muscles during acute hyperinflation. Hyperinflation was provoked in two asthmatic and three normal subjects by progressively doubling doses of histamine. Changes in lung volume were determined with magnetometers and with a body plethysmograph. Intercostal muscle activity was recorded with surface electrodes and diaphragmatic activity with esophageal electrodes. Tonic activity was defined as electrical activity in the electromyogram present at end expiration. After histamine the maximal observed increase in plethysmographic thoracic gas volume in the five subjects was 29.8 +/- 6.4% of control (mean +/- SE). Hyperinflation was accompanied by a significant increase in tonic activity of the intercostal muscles (P < 0.01) and the diaphragm (P < 0.01). There was a significant correlation between the increase in thoracic gas volume and the increase in tonic intercostal (r = 0.82, P = 0.003) and diaphragmatic (r = 0.89, P = 0.003) activity. We conclude that histamine-induced hyperinflation is accompanied by persistent inspiratory muscle activity throughout expiration.

Adult↗
PubMed1979

The consequences of diaphragmatic muscle fatigue in the newborn infant.

We have previously demonstrated that diaphragmatic muscle fatigue can be diagnosed in infants from spectral frequency analysis of the surface diaphragmatic electromyogram. This requires a digital computer, but the analysis takes several days. Spectral frequency changes, however, can be accurately reflected by band pass filtering and expressing the ratio of high-frequency power to low-frequency power. A fall in this ratio of greater than 20% indicates muscle fatigue. Using a simple analog device to obtain this ratio permits the results to be immediately available; we have used this method to study weaning from mechanical ventilators in ten infants. With a successful weaning step there is no significant change in the ratio, whereas an unsuccessful weaning step invariably leads to a decrease in the ratio of greater than 20%, which precedes CO2 retention and clinical deterioration. These data indicate that diaphragmatic muscle fatigue plays an important role in the infant's response to lung disease. Monitoring of the high/low frequency ratio may be helpful in weaning infants from assisted ventilation.

Computers, Analog↗
PubMed1979

Diaphragmatic muscle tone.

It is generally believed that there is a scarcity of muscle spindles in the diaphragm and that there is no tonic activity at end expiration. This conclusion is based mainly on animal studies and the difficulty in differentiating tonic electromyogram activity from noise. We have, however, found a number of muscle spindles in the newborn human diagphragm, concentrated in the region of the central tendon. We also tried to detect tonic activity by decreasing it (by rapid-eye movement (REM) sleep or anesthesia) or increasing it (with abdominal loading). During REM sleep in five infants and five adults, using subcostal electrodes were observed a marked fall in tonic activity (P less than 0.001) compared to non-REM or quiet sleep. We also observed a reduction in diaphragmatic tonic activity with halothane anesthesia (P less than 0.001). With esophageal electrodes in adult subjects, there was a rise in tonic diaphragmatic activity proportional to the amount of abdomina load (P less than 0.001). We conclude that there are muscle spindles in the human diaphragm and that there is tonic activity at end expiration.

Adult↗
PubMedDate not supplied

[Stereoselective protein binding of non-steroidal anti-inflammatory agents. Pharmacological implications].

Non steroidal anti-inflammatory drugs (NSAIDs) contain a chiral carbon alpha to carboxyl function. Except for naproxen, chiral NSAIDs are marketed for clinical use as racemate, ie an equimolar mixture of the two enantiomers R(-) and S(+). However, in vitro studies have shown that the anti-inflammatory activity exists almost solely in the S form. The unbound fraction is able to diffuse into tissues and to reach sites of action. It represents also the pharmacological active form. Stereoselective protein binding studies carried out at various concentrations of NSAIDs and albumin are used to evaluate the free fraction of the active enantiomer. Two optical isomers do not interact in the same manner with proteins and this binding stereoselectivity depends on NSAID and experimental conditions. Thus, it seems difficult to predict the in vivo free concentration of each enantiomer and protein binding experiments should be achieved taking into account the physiopathological parameters which influence this biological process. This enantioselectivity is determinant for the pharmacokinetic properties and could be responsible of the parameters variation obtained for each enantiomer. It could explain the variability in response to NSAIDs too. In fact, the anti-inflammatory effect is directly function of the free concentration of the S isomer. To correlate the NSAID dose with its activity, it should be better to determine this free fraction in the site of action, in particular in the synovial fluid. But the clinical response, as for example the antalgic effect, remains very far from the pharmacological activity, ie the cyclooxygenase inhibition.

Anti-Inflammatory Agents, Non-Steroidal↗