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Biomedical subjects

M R Morris

Publications and source records attributed to M R Morris.

At least 37 records · Page 2Linked to original sources
PubMed1996

Onlay bone augmentation with an osteoinductive implant.

The repair of contour defects of craniofacial bone can be accomplished by several methods, including autogenous bone grafts, demineralized bone, and alloplastic materials. The objective of this study was to assess a biodegradable, xenogeneic, osteoinductive implant for craniofacial onlay bone augmentation. Twelve New Zealand White rabbits each had craniofacial onlays consisting of three experimental materials: 1) autograft; 2) allogeneic, demineralized block implant; and 3) partially purified osteoinductive protein (osteogenin) with allogeneic collagen and 50:50 poly (DL-lactide-co-glycolide). Implants with host bone were recovered after 20 weeks and assessed by histomorphometric methods. There was no evidence of adverse local reaction to the three treatments. No significant difference in bone replacement or bone density resulting from each of the implant types was demonstrated. In conclusion, the osteoinductive implants were well tolerated, and over the 20-week period they appeared to maintain their contour as onlays.

Animals↗
PubMed1994

Initial clinical experience with dextran-coated superparamagnetic iron oxide for detection of lymph node metastases in patients with head and neck cancer.

PURPOSE: To investigate the efficacy of magnetic resonance (MR) imaging with dextran-coated superparamagnetic iron oxide in the differentiation of metastatic and benign nodes in patients with head and neck cancer. MATERIALS AND METHODS: MR imaging was performed before and after intravenous administration of iron oxide in 12 patients. Ninety-one pathologically proved nodes were visually analyzed, and 66 lymph nodes were quantitatively analyzed by measuring signal intensity in visually selected regions of interest. RESULTS: Forty of 42 histologically proved metastatic nodes and 41 of 49 benign nodes were detected, yielding 95% sensitivity and 84% specificity. The signal intensity ratio of benign nodes was substantially lower than that of metastatic nodes, indicating better differentiation of metastatic and benign nodes. Furthermore, 13 of 14 normal-sized nodes were detected. CONCLUSION: MR imaging with iron oxide can enable specific differentiation of metastatic and benign nodes in patients with head and neck cancer. This agent may potentially enhance the detection of metastatic lymph nodes and deserves further investigation.

Adult↗
PubMed1993

Electron ionization-tandem mass spectrometry of glycosphingolipids. Part II. The identification of a carbohydrate sequence corresponding to a novel repetitive blood group A heptaglycosylceramide.

In a previous paper, the presence in human kidney vein tissue of a novel blood group A heptaglycosylceramide based on the type-3 carbohydrate chain GalNAc alpha 1-3(Fuc alpha 1-2)Gal beta 1-3GalNAc alpha 1-3(Fuc alpha 1-2)Gal beta 1-4Glc beta 1-1 Ceramide, was suggested based on thin-layer immunostaining and electron ionization mass spectrometry. Ions corresponding to a structure containing two deoxyhexoses, two hexosamines and three hexoses were identified, but no information was obtained from mass spectrometry concerning the carbohydrate sequence. In the present paper, we report the identification of carbohydrate sequence ions corresponding to a type-3 chain A heptaglycosylceramide by electron ionization-tandem mass spectrometry of a permethylated-reduced glycosphingolipid mixture isolated from human kidney vein tissue. The use of a microchannel-plate-array detector increased the sensitivity for collision-induced dissociation spectra by a factor of at least ten over a conventional electron multiplier.

Blood Group Antigens↗
PubMed1992

Efficacy of gadoteridol for contrast-enhanced magnetic resonance imaging in children.

RATIONALE AND OBJECTIVES: This study assesses the efficacy of gadoteridol for contrast-enhanced magnetic resonance imaging (MRI) in children. METHODS: Patients were examined by MRI before and after receiving 0.10 mmol/kg gadoteridol. Blinded and unblinded readers analyzed brain and spine MRI studies from a multicenter clinical trial involving 101 patients at 11 sites. Ninety-two cases (76 brain, 16 spine) were evaluated by unblinded investigators, and 91 cases (76 brain, 15 spine) were evaluated by three neuroradiologists unaffiliated with any investigational site and blinded to clinical information. RESULTS: Unblinded readers noted enhancement of brain pathology in 70% of cases versus 50% to 67% among blinded readers. Unblinded readers determined that additional diagnostic information was available after contrast in 82% of brain studies (average, 64% for blinded readers) and would have changed patient diagnoses in 48% of these studies (average, 46% for blinded readers). In spine cases, enhancement of pathology was noted in 38% (unblinded) and 33% to 40% (blinded). Additional diagnostic information was available after contrast in 63% of spine studies (unblinded), or an average of 58% (blinded), and patient diagnoses would have changed in 20% (unblinded), or an average of 59% (blinded). CONCLUSIONS: Gadoteridol is suitable for enhanced MRI detection, localization, and characterization of central nervous system pathology in children.

Adolescent↗
PubMed1991

The temporoparietal fascia flap in head and neck reconstruction.

The temporoparietal-galeal system of flaps provides the head and neck surgeon with a reliable source of pliable, well vascularized local tissue capable of reconstructing auricular, oropharyngeal/base of tongue/lateral floor of mouth, dural, mandibular, and facial defects. This report provides a description of the types of flaps available, methods of dissection, and examples of reconstructive uses with this versatile tissue.

Carcinoma↗
PubMed1989

Aggressive paranasal sinus ossifying fibroma.

Sixty-one cases of an aggressive OF involving the paranasal sinus area are reviewed from the literature. We describe another case of this unusual lesion in an 11-year-old girl. These tumors share a similar radiographic appearance, aggressive clinical behavior, and tendency for recurrence after incomplete treatment. Our experiences show that active OF accurately describes this entity and avoids the confusing histologic nomenclature usually encountered. The head and neck surgeon should be aware of this diagnosis so aggressive en bloc resection can be employed whenever possible.

Child↗
PubMed1977

Influence of cations at the plasma membrane in controlling polysaccharide secretion from sycamore suspension cells.

1. Three soluble polysaccharides and a soluble protein containing hydroxyproline were secreted by sycamore suspension cultures. l-[1-(3)H]Fucose was incorporated solely into the fucose of fucoxyloglucan and l-[1-(14)C]arabinose mainly into the arabinose of arabino-galactan. [U-(14)C]Glucose was a general precursor for soluble protein and polysaccharides. 2. The steady-state rate of secretion of all the polymers was increased within seconds of adding various electrolytes and polyelectrolytes to the growth medium. The increased secretion was induced by cations at the outer surface of the plasma membrane. It was brought about by a stimulation of the normal mechanisms of cell-wall polysaccharide secretion. It was partly inhibited by anaerobiosis or sodium arsenate and was unaffected by temperature changes in the range 0-35 degrees C. 3. The precursor pool from which secretion was induced contained completely synthesized polysaccharides and was probably located in the Golgi-derived vesicles. The results indicated that the endoplasmic reticulum did not secrete polysaccharide directly to the cell exterior. 4. The various cations probably induced secretion by causing a depolarization of the negative electric potential of the cell surface, and this resulted in the fusion of vesicles with the plasma membrane. 5. Analogy with exocytosis and pinocytosis in various animal tissues suggested that the decreased surface potential brought about membrane fusion by causing an increase in plasma-membrane permeability to Ca(2+). 6. The results showed that the fusion of vesicles with the plasma membrane was rate-limiting and a potential control point. Auxin-stimulated cell-wall deposition could be a result of a stimulated influx of Ca(2+) causing vesicle fusion with the plasma membrane.

Calcium Chloride↗