Behaviour of fibroblasts and epidermal cells cultivated on analogues of extracellular matrix.

A porous collagen sponge can be used for supporting epidermal cells and fibroblasts in order to manufacture an artificial skin. Fibroblasts were grown on analogues of extracellular matrix containing collagen and glycosaminoglycans and/or glycoproteins. Cell replication, and also infiltration of fibroblasts, were enhanced by the presence of hyaluronic acid and/or fibronectin.

Regional cerebral blood flow in stroke: hemispheric effects of cognitive activity.

Regional cerebral blood flow (rCBF) was measured with the xenon-133 inhalation technique in 15 patients with unilateral cerebral infarction and 12 matched controls. Measurements were performed during a standard resting baseline condition and during the performance of standardized verbal analogies and spatial line orientation tasks. Resting and activated CBF were lower in patients than in controls, and there were differences in the hemispheric pattern of activated CBF.

Metabolic and clinical correlates of acute ischemic infarction.

We studied cerebral metabolism, anatomy, and clinical status in 36 patients with acute cerebral ischemia. Results from FDG-PET were compared with CT to find the relationships between the metabolic, anatomic, and clinical findings. Metabolic abnormalities seen on PET frequently were more extensive than the corresponding CT findings.

Fibroblast growth on a porous collagen sponge containing hyaluronic acid and fibronectin.

We have previously shown that the presence of fibronectin (FN) and/or hyaluronic acid (HA) in a 3-dimensional type I collagen sponge enhances wound healing in vivo. In the present study the same material was used as a support for growth of fibroblasts in vitro. Using radiochemical techniques, scanning electron and light microscopy, the properties of fibroblasts cultured on the collagen sponge or on the sponge containing HA or FN have been compared with cultures grown on plastic dishes.

Recovery of vision after ischemic lesions: positron emission tomography.

We used [18F]fluoro-2-deoxyglucose positron emission tomography (PET) to study serial changes in the local cerebral metabolic rate of glucose in 5 patients with ischemic lesions of the posterior afferent visual system causing homonymous visual field defects. All 5 patients had striking impairment of glucose metabolism in the striate cortex shortly after ictus. In 2 patients, visual field defects abated, and repeat PET scans showed reduced size of the metabolic lesion and improvement of striate metabolism.

Cerebral glucose consumption following verbal auditory stimulation.

We studied the effect of auditory stimulation upon cerebral glucose metabolism in young normals. The stimulus consisted of a non-English discourse which was presented monaurally to 10 normal blindfolded subjects (5 left ear, 5 right); the opposite ear was plugged. Six subjects studied blindfolded and with ears plugged served as controls.

Diffusivity of 125I-labelled macromolecules through collagen: mechanism of diffusion and effect of adsorption.

Diffusion of angiotensin II, albumin and aldolase was studied through collagen membranes with swelling ratios between 4 and 15. The diffusion coefficient was measured from the time-lag for the onset of steady-state flux through the membrane. Binding of macromolecules to collagen was evaluated from the results of sorption studies conducted as a function of macromolecular concentration.

Regional brain function in schizophrenia. I. A positron emission tomography study.

Local cerebral glucose metabolism was determined with 18-F-fluorodeoxyglucose using positron emission tomography in a sample of 12 unmedicated schizophrenics and 12 matched normal controls. The data were analyzed for absolute metabolic rates and region/whole-brain ratios using the cortical-subcortical, antero-posterior, and laterality dimensions. Lobar areas within cortical regions were also compared.

Increased aortic root stiffness associated with osteogenesis imperfecta.

M-mode echocardiograms obtained from 31 patients with types I and IV osteogenesis imperfecta (OI) were evaluated for increased aortic root dilatation and wall stiffness. Four patients were observed to have dilated aortic roots. The pressure-strain elastic moduli (Ep) of the majority of OI patients studied were significantly different from those of age-matched controls; the observed values of Ep were both greater and less than that of controls.

Local cerebral metabolic changes in acute ischemic strokes.

Positron emission tomography (PET) studies with 18F deoxyglucose were completed in 35 patients with acute ischemic strokes. Twelve cases were studied within 72 h, 23 between 4 and 14 days. Results indicate the functional and prognostic significance of early tomography studies of metabolism, and anticipate possible use of metabolic imaging in the evaluation of treatment.

Antibiotic prophylaxis in high-risk head and neck surgery: one-day vs. five-day therapy.

Patients who undergo major contaminated surgery of the head and neck benefit from perioperative antibiotic prophylaxis. This study was developed to determine if 5 days of antibiotic administration would be more effective than 1 day. A multi-institutional prospective randomized double-blind study was designed.

Collagen-based wound dressings: control of the pore structure and morphology.

Collagen-based sponges have been used as both temporary and permanent coverings for dermal defects in animals and humans. Cellular ingrowth within such a sponge has been shown to depend on the porosity and the presence of fibrous structure. Collagen sponges were made by freezing and freeze-drying dispersions under acidic conditions.

Diffusivity of 125I-calmodulin through collagen membranes: effect of source concentration and membrane swelling ratio.

Diffusivity of 125I-calmodulin (MW congruent to 17,000) through collagen membranes was studied as a model for the release of macromolecules from collagen matrices. The diffusion coefficient of calmodulin through collagen membranes was determined from time-lag experiments conducted in a dialysis cell at 24 degrees C. Based on time-lag experiments, the diffusion coefficient was observed to be a function of source concentration and membrane swelling ratio after denaturation.

Collagen-based wound dressing: effects of hyaluronic acid and fibronectin on wound healing.

Our previous studies have shown that a collagen-based wound dressing induces the spatial deposition of wound tissue. This study was conducted to determine the effects of hyaluronic acid and fibronectin on wound healing. These macromolecules play an important role in wound healing, embryonic development and cellular migration in vitro.

Non-invasive assessment of aortic mechanical properties.

Echocardiography and sphygmomanometry were used to noninvasively assess the changes in aortic mechanical properties associated with aging. Fifty normal individuals were examined and were divided into three groups: young (less than 35 years of age), middle-aged (35-55), and old (greater than 55). Experimental measurements indicated that elastic aortic stiffness in the circumferential direction increased with increased age.

Collagen fiber formation in repair tissue: development of strength and toughness.

Dermal repair tissue shows a progressive increase in collagen content which may be related to the wound tensile strength. Wound strength and extensibility are lower than those found in normal skin. In animals, wounds closed by metal clips are chosen as a model to study the proliferative and remodeling phases of healing from a mechanical and morphological point of view.

Operative complications of tracheoesophageal puncture.

Tracheoesophageal puncture is not a complex procedure; nevertheless, significant complications are possible. In the last four years we have performed this procedure in 47 patients. Seven of them (15%) sustained significant complications related to the procedure.

Collagen deposition during wound repair.

Collagen fiber diameters, amount of birefringent collagen (brightness) and birefringence retardation were measured in implanted collagen-based sponges containing hyaluronic acid (HA) and fibronectin (FN). In the presence of HA and FN, increased number of fibroblasts and brightness were observed 6 days after wounding. Increased brightness in the presence of HA and FN reflected increased deposition of oriented collagen fibers.

The molecular structure and lubricating activity of lubricin isolated from bovine and human synovial fluids.

Lubricin was isolated from bovine ankle, metacarpophalangeal and knee and human knee synovial fluids. The lubricins isolated from the bovine joint fluids had the same amino acid and carbohydrate compositions, but differences were observed in the relative molecular masses. The Mr values of bovine metacarpophalangeal and ankle lubricin determined by light-scattering measurements were about 200 000, whereas values of 132 000 and 143 000 were obtained for the bovine knee lubricin.

Mechanical analysis of hypertrophic scar tissue: structural basis for apparent increased rigidity.

The mechanical behavior of normal human skin and hypertrophic scar tissue (HST) is compared using constant-strain-rate and successive stress-relaxation uniaxial loading programs in vitro. HST is less extensible, requires more energy to be stretched in the physiologic range, and stores strain energy less efficiently than normal skin. The explanations for the differences observed between the mechanical behavior of normal skin and HST are based on the differences in their composition and structure.

Collagen fibrillogenesis in vitro: comparison of types I, II, and III.

The self-assembly of pepsin-extracted types I, II, and III collagen was studied to determine how differences in the triple-helical structure between collagen types influence in vitro collagen fibrillogenesis. Collagen types I, II, and III were extracted and purified from bovine sources, and were studied in solution by laser light scattering, pH titration, and determination of turbidity-time curves. The molecular weights were between 280,000 and 289,000, while the translational diffusion coefficients and particle scattering factors at 175.