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Biomedical subjects

H Muller

Publications and source records attributed to H Muller.

At least 19 recordsLinked to original sources
PubMed1991

Induction of fracture healing using fibrous calcium phosphate composite spherulites.

The healing of large fractural defects is a difficult clinical problem, especially if it occurs in elderly or otherwise debilitated patients. The objective of this study is to determine if a new formulation of fibrous calcium phosphate crystals would induce fracture healing in vivo. Fibrous calcium phosphate (FCP) can be grown with unique size, shape, and surface area characteristics as a resorbable or nonresorbable, osteoconductive or osteoinductive material. In comparison with other conventional calcium phosphate particulates, FCP particles possess approximately x 100 to x 1000 more surface area. One-and-one-half centimeter sections were removed from the ulnas of 12 rabbits. Three groups had fibrous calcium phosphate spherulites (4-8 microns, 150-300 microns, 400-600 microns) mixed with collagen and a growth factor-bonding agent injected into the ulnar defect. One site per group was not treated. X-rays were obtained during the study and the percentage of the ulna defect filled in by callous was measured. The percentage was recorded as the amount of fracture healing for each site. Histologic examination of the ulnas was performed following sacrifice at 12 weeks. Fracture sites treated with fibrous calcium phosphate showed significantly greater healing (0.79 +/- 0.3) than control animals (0.36 +/- 0.1) (P less than .05, unpaired t-test) radiographically. Histologic examination showed that the spherulites remain in situ and become embedded within the new growth of fibrous tissue, collagen and new bone. Radiographically and histologically, FCP preparations appear to accelerate fracture healing by inducing new bone formation, into which they often become embedded.

Animals↗
PubMed1988

A peculiar complication in Le Fort I osteotomy.

In two cases of routine Le Fort I osteotomy in secondary cleft palate surgery, a swelling noted in the antral mucosa was biopsied. In both cases, histological examination resulted in a diagnosis of odontogenic myxoma. After analysis of the radiographs, it was concluded that the biopsies were taken from displaced tooth germs. The close histological similarity between myxoma on the one hand and dental papilla tissue, a thickened tooth follicle and a thickened or polypoid antral mucosal lining on the other is discussed.

Adolescent↗
PubMed1986

Transient catecholamine modulation of neutrophil activation: kinetic and intracellular aspects of isoproterenol action.

Modulation of neutrophil activation by catecholamines may reflect regulatory mechanisms that couple beta-adrenergic and N-formyl peptide receptors to antagonistic biochemical pathways. We examined kinetic and mechanistic aspects of the inhibition by catecholamines of neutrophil activation by formyl peptides. Inhibition of oxidant production by isoproterenol (ISO) was detected as low as 3 nM, had an ID50 of 10(-7) M, and could be blocked and reversed by propranolol. Recovery of cell function occurred over a period of minutes when the concentration of ISO was less than 10(-6) M. These observations are discussed in terms of the interaction of ISO with the adrenergic receptors. The site of catecholamine action is addressed. ISO neither influences formyl peptide-receptor interaction nor does it inhibit oxidant production by phorbol ester. These results suggest an impairment of intracellular signalling processes that couple the formyl peptide-receptor binding to cell activation. We observed inhibition of intracellular Ca++ elevation by ISO only at low formyl peptide concentrations. This inhibition is consistent with a partial inhibition of phosphoinositide metabolism, which was observed. Several other cell responses, including actin polymerization and right angle light scatter, are minimally inhibited by 10(-6) M ISO indicating that the cell activation process is not entirely obliterated. The presence of catecholamine and formyl peptide results in a synergistic elevation of cAMP. The intracellular targets of ISO action may be regulated by cAMP dependent kinases and could follow a branchpoint in the activation sequence that leads distinctly to oxidase activation and cytoskeletal activation.

Actins↗
PubMed1985

A sonographic assessment of neonatal renal parameters.

One hundred twenty infants ranging in weight from 600 to 4,000 grams were entered into a prospective sonographic study to establish normal renal growth parameters. Renal cortical echogenicity was demonstrated to decrease with increasing infant weight. Observations on the use of Doppler analysis for assessing renal vascular flow are presented.

Body Weight↗
PubMed1982

[Kveim test performed with antigen obtained from lymph nodes].

This is our second paper about the Kveim test performed with G-77 antigen obtained from sarcoid lymph nodes. The antigen was tested in 46 patients with proved or suspected sarcoidosis and in 50 controls. Results were: 1) In 27 patients with active proved sarcoidosis and without treatment the test was positive in 85,1% (23/27 patients); 2) In 2/3 patients with proved sarcoidosis after therapeutic remission for more than two years and without treatment presently, the results were positive in one of them; 4) In 14 patients suspected to have sarcoidosis but showing lesions only on the skin the test was positive in 58,1% (8/14 patients); 5) In 48 controls the test was negative but in 2 it was positive. Our results agree with those of the literature.

Antigens↗
PubMed1981

[Value of morphine derivatives administered by the peridural route per- and postoperatively].

The existence of opiate receptors in the spinal cord led the authors to seek a clinical application. 1 - A peroperative injection of morphine was administered in 170 cases: 0.005 mg/kg of fentanyl in 105 cases and 0.05 mg/kg of morphine in 65 cases. In addition to usual surveillance (blood pressure, heart rate and central venous pressure), more extensive haemodynamic investigations were undertaken in 20 patients using a Swan-Ganz catheter. Blood concentrations (11 cases) and CSF concentrations (2 cases for each time of measurement) were determined in the case of fentanyl. In 20 patients (10 of whom had received fentanyl and 10 morphine) there was sophisticated cardio-respiratory surveillance postoperatively. 2 - 0.05 mg/kg or morphine (404 cases), 50 mg of pethidine (10 cases) and 0.1 mg of fentanyl (10 cases) were injected postoperatively. A comparison was made of the analgesia obtained. After three types of anaesthesia: epidural with bupivacaine with intubation (10 cases), halothane with intubation (10 cases) and neuroleptanaesthesia (10 cases), an injection was given of 0.05 mg/kg of morphine, with cardiorespiratory surveillance. Results were as follows: 1 - There were no significant variations in haemodynamic parameters peroperatively, indicative of adequate analgesia. Blood concentrations of fentanyl were as follows: 3.2 +/- 2.1 ng/ml after 10 minutes, 2 +/- 1.7 ng/ml after one hour, 1.4 +/- 1 ng/ml after two hours and 0.4 +/- 0.3 ng/ml after four hours. CSF concentrations were much higher; 34 ng/ml after one hour, 30 ng/ml after two and three hours and 25 ng/ml after four hours. No cardio-respiratory depression was seen after the peroperative injection of morphine. 2- The duration of analgesia following a postoperative injection of a morphine derivative was as follows: morphine 17.3 +/- 3.9 hours, pethidine 3.5 +/- 0.5 hours, and fentanyl 5.1 +/- 0.7 hours. The epidural injection of morphine after neuroleptoanaesthesia caused respiratory depression in two of the 10 cases, with a rise in pCO2 of 0.45 and 0.52 KPa. The results are discussed and compared with those of other authors. In conclusion, the authors emphasize the advantages of this method which makes it possible to obtain with smaller doses analgesia of longer duration than following a systemic injection of morphine, whilst at the same time decreasing the side effects.

Anesthesia, Epidural↗
PubMed1980

Studies on the association of NAD glycohydrolase with membranes in calf spleen.

The subcellular distribution of NAD glycohydrolase was studied by fractionation of calf spleen homogenates using differential and discontinuous density gradient centrifugations. The highest amount of NAD glycohydrolase activity was associated with microsomes, which in this tissue were found to contain, in addition to endoplasmic reticulum, a large proportion of vesicles derived from plasma membranes. The distribution pattern of NAD glycohydrolase was found to parallel that of plasma membrane markers. When microsomal vesicles were treated with digitonin, NAD glycohydrolase activity and plasma membranes specifically increased in density. We conclude that in calf spleen the bulk of NAD glycohydrolase is associated with plasma membranes. Microsomal NAD glycohydrolase was associated with sealed vesicles; its activity could not be increased by disruption of the sidedness of the vesicles. This result and further observations based on the known restricted permeability of biological membranes to charged substances, and on the activity of the enzyme with non-penetrating substrates and inhibitors, indicate that the NAD glycohydrolase active site is located on the exterior side of the vesicles. It is proposed that calf spleen NAD glycohydrolase is an ecto-enzyme.

Animals↗