Search PubMed⌕ Search

Biomedical subjects

H Mohammed

Publications and source records attributed to H Mohammed.

At least 37 records · Page 2Linked to original sources
PubMed1995

Local and remote matrix responses to chondrocyte-laden collagen scaffold implantation in extensive articular cartilage defects.

Chondrocyte-laden collagen scaffolds were evaluated in extensive cartilage defects in an equine model. Arthroscopic techniques were used to implant a chondrocyte-collagen culture product in 15-mm defects in the lateral trochlear ridge of the femoropatellar joint of 12 horses. Ungrafted control defects were formed in the opposite joint. Groups of six horses were terminated at 4 and 8 months after implantation and the repair sites, adjacent cartilage, and remote cartilage within each femoropatellar joint examined biochemically. Eight months following surgery the relative proportions of type II collagen in grafted and ungrafted defects, determined using the ratio of cyanogen bromide cleavage products alpha 1(II)CB10/alpha 2(I)CB3,5, were not significantly different (31.57 +/- 2.76% and 26.88 +/- 2.76%, respectively). Aggrecan content was significantly improved in grafted defects (85.61 +/- 6.51 and 74.91 +/- 10.31 micrograms/mg dry weight). Cartilage surrounding grafted defects also showed improved maintenance of cartilage glycosaminoglycan content. Thus, chondrocyte grafting in collagen scaffold vehicles improved the aggrecan content in extensive cartilage defects and surrounding normal cartilage. However, given the continued disparity between repair tissue and normal cartilage aggrecan content, and the low proportion of type II collagen in grafted defects, the utility of collagen scaffolds for chondrocyte grafting of large cartilage defects seems limited.

Animals↗
PubMed1995

Recombinant OspA protects dogs against infection and disease caused by Borrelia burgdorferi.

Twenty-two specific-pathogen-free beagles were vaccinated with recombinant OspA (ospA gene derived from Borrelia burgdorferi B31) alone or with adjuvant (QuilA, Montanide ISA25, or aluminum hydroxide) at 6 weeks of age. Thirteen dogs were used as nonvaccinated controls with or without adjuvant. Three dogs were kept as contact controls and received neither vaccine nor challenge. Six weeks or 6 months after the first vaccination, the vaccinated (20 of 22) and nonvaccinated dogs (13) were challenged by exposure to adult ticks (Ixodes scapularis) naturally that were infected with B. burgdorferi (tick infection rate, > or = 60%) and that were collected from Westchester County, N.Y. Protection from infection was evaluated by culture for B. burgdorferi from skin biopsies taken near the sites of tick bites. Skin biopsies were taken at monthly intervals for 3 months. B. burgdorferi was not isolated from any of the vaccinated dogs. In contrast, 12 of 13 control dogs challenged by exposure to the ticks were culture positive. The histopathology of the joint capsules 3 months after the challenge was used to evaluate protection from arthritis. Eight of 13 control dogs showed synovitis in single or multiple joints, while only 1 of the 22 vaccinated dogs had a single focus of mild inflammation in a single joint. At the time of the challenge, the vaccinated dogs had antibody to B. burgdorferi, which was demonstrable by kinetic enzyme-linked immunosorbent assay, Western blotting (immunoblotting), and a serum growth inhibition assay. The vaccinal antibody declined gradually after the challenge, especially in dogs vaccinated with OspA without adjuvants. Antibodies in the challenge control dogs were only detectable by 4 to 6 weeks after the challenge and remained at high levels until the termination of the study. Contact control dogs showed no antibody responses or histopathologic lesions and were culture negative. By Western blot analysis, antibodies to OspA first appeared in the sera of vaccinated dogs 3 weeks after the first vaccination. The absence of additional bands after the challenge suggests that infection in vaccinated dogs was blocked. Results from this study show that vaccination with recombinant OspA protected dogs against infection and disease after an experimental challenge with B. burgdorferi by exposure to ticks.

Animals↗
PubMed1994

Button versus buttonless castings for removable partial denture frameworks.

Casting removable partial dentures (RPDs) without completely filling the sprue channels and generating casting buttons would result in saving metal and making more defect-free castings. This investigation tested whether a complete and sound RPD casting can be obtained when a minimal amount of metal is used. A factorial experimental design, three spruing methods, two metal feeding directions, and two different weights of metal were used to cast 60 Kennedy class II, modification 1 RPDs. The metal used to cast each framework was either enough to result in a full button or in no button. Visual and radiographic examinations and counting of defects were made by two independent operators who were unaware of the spruing method, feeding direction, or amount of metal used to make the framework. The completeness of the casting and the presence of porosities were evaluated for clasps, major connectors, and meshworks. The use of minimal metal to cast RPDs was equally as successful as using enough for a full button, provided that the appropriate spruing arrangement and metal feeding direction were chosen. Indirect metal feeding for maxillary RPDs was successful with the proper spruing arrangement.

Chromium Alloys↗
PubMed1992

Accuracy of ultrasonography in the detection of severe hepatic lipidosis in cats.

The accuracy of ultrasonography in detection of feline hepatic lipidosis was studied retrospectively. The following ultrasonographic criteria were associated positively with severe hepatic lipidosis: the liver hyperechoic, compared with falciform fat; the liver isoechoic or hyperechoic, compared with omental fat; poor visualization of intrahepatic vessel borders; and increased attenuation of sound by the liver. In a group of 36 cats with clinically apparent hepatobiliary disease and in which liver biopsy was done, liver hyperechoic, compared with falciform fat, was the best criterion for diagnosis of severe hepatic lipidosis with 91% sensitivity, 100% specificity, and 100% positive predictive value.

Animals↗
PubMed1991

Effects of sodium hyaluronate on tendon healing and adhesion formation in horses.

Sodium hyaluronate reduces adhesions after tendon repair in rodents and dogs, and has been used in limited clinical trials in people. To evaluate its effect on tendon healing and adhesion formation in horses and to compare these effects with those of a compound of similar visco-elastic properties, a study was performed in horses, using a model of collagenase injection in the flexor tendons within the digital sheath. Eight clinically normal horses were randomly allotted to 2 groups. Adhesion formation between the deep digital flexor tendon and the tendon sheath at the pastern region was induced in the forelimbs of all horses. Using tenoscopic control, a 20-gauge needle was inserted into the deep digital flexor tendon of horses under general anesthesia and 0.2 ml of collagenase (2.5 mg/ml) was injected. The procedure was repeated proximally at 2 other sites, spaced 1.5 cm apart. A biopsy forceps was introduced, and a 5-mm tendon defect was created at each injection site. Group-A horses had 120 mg of sodium hyaluronate (NaHA) gel injected into the tendon sheath of one limb. Group-B horses had methylcellulose gel injected at the same sites. The contralateral limbs of horses in both groups served as surgical, but noninjected, controls. Horses were euthanatized after 8 weeks of stall rest. Ultrasonographic evaluation revealed improved tendon healing after NaHa injection, but no difference in peritendinous adhesion formation. Tendon sheath fluid volume and hyaluronic acid (HA) content were greater in NaHA-treated limbs. Gross pathologic examination revealed considerably fewer and smaller adhesions when limbs were treated with NaHA. However, significant difference in pull-out strengths was not evident between NaHA-treated and control limbs. Histologically, the deep digital flexor tendon from the NaHA-treated limbs had reduced inflammatory cell infiltration, improved tendon structure, and less intratendinous hemorrhage. Treatment with methylcullulose had no significant effect on tendon healing, adhesion size, quantity, or strength or on the volume and composition of the tendon sheath fluid. Sodium hyaluronate, administered intrathecally, appears to have a pharmaceutically beneficial action in this collagenase-induced tendinitis and adhesion model in horses.

Animals↗
PubMed1991

Characteristics of digital flexor tendon sheath fluid from clinically normal horses.

Physical, biochemical, and cytologic properties of synovial fluid from digital flexor tendon sheaths of clinically normal horses were investigated. Tendon sheath fluid was pale yellow, clear, and did not clot. Volume of fluid within a tendon sheath varied minimally, with a mean of 2.11 ml. Total erythrocyte counts were higher than values observed in normal equine joint fluid, whereas values for total leukocyte count (770 +/- 73 cells/mm3), viscosity (6.05 +/- 0.58 cs), and protein concentration (7.87 +/- 0.03 mg/ml) were similar to those in joint fluid. Large mononuclear cells were the predominant synovial fluid cell type. Mean hyaluronic acid concentration (0.74 +/- 0.02 mg/ml) and mucinous precipitate quality were lower than values in joint fluid.

Animals↗
PubMed1991

The POEMS syndrome.

The POEMS syndrome is an unusual disorder manifesting primarily as a peripheral sensorimotor neuropathy in association with a monoclonal gammopathy. The importance of its recognition is that significant clinical improvement may result from localization and treatment of the underlying plasma cell tumour.

Humans↗
PubMed1988

Evaluation of breed as a risk factor for sarcoid and uveitis in horses.

The relationship between breed and the risk of developing sarcoid tumours or uveitis of unknown etiology was evaluated in a retrospective study of 16242 equine cases admitted between 1975 and 1987 to the New York State College of Veterinary Medicine Large Animal Hospital, and 3198 equine tissue samples sent to the New York State Veterinary Diagnostic Laboratory between 1977 and 1987. Of 120 sarcoid cases from the Large Animal Hospital, sarcoids were twice as likely to develop in Quarter Horses (odds ratio, OR = 1.8, P less than 0.05) relative to Thoroughbreds and less than half as likely to develop in Standardbreds (OR = 0.2, P less than 0.001) relative to Thoroughbreds. Similarly, of 376 sarcoid cases from the Diagnostic Laboratory, Quarter Horses had a significantly higher risk of developing sarcoid (OR = 2.0, P less than 0.001) relative to Thoroughbreds, while Standardbreds had a significantly lower risk of developing sarcoid (OR = 0.5, P less than 0.05) relative to Thoroughbreds. In the uveitis diagnosis category, Appaloosas had a significantly higher risk of developing uveitis (OR = 6.4, P less than 0.001) relative to Thoroughbreds, while Standardbreds had a significantly lower risk of developing uveitis (OR = 0.4, P less than 0.05) relative to Thoroughbreds.

Animals↗
PubMed1987

Infection with bluetongue and related orbiviruses in the Sudan detected by the study of sentinel calf herds.

Using two sentinel calf herds, the seasonal incidence of bluetongue in central Sudan was shown to be a predictable event related to the rainy season and to vector population. Seroconversions to bluetongue virus (BTV) were detected only between July and December. Neutralizing antibodies to 16 BTV serotypes (1-10, 12, 14, 17, 20-22) were present in animals from both sentinel herds. The use of a blocking enzyme-linked immunosorbent assay made possible the distinction between infections due to BTV and those due to infections with other orbiviruses. Sera from 13 calves at Shambat and from 17 at Um Benein gave agar-gel tests indicative of BTV infections not attributable to any of the 22 serotypes, suggesting the presence of new serotypes of BTV. Sera from 30 calves gave results interpreted as evidence of infection with BTV-related viruses, rather than BTV serotypes. Comparing these results with those reported from Kenya, we suggest that the pattern of the disease and the types involved are similar in both countries and that the movements of the Intertropical Convergence Zone (I.T.C.Z.) may carry infected midges northwards into the Sudan at the start of the rainy season and southward at the end of this period.

Animals↗
PubMed1981

Estimation of physiologic stresses with a natural tooth considering fibrous PDL structure.

Finite element analysis is used to determine the physiological stress values in the natural tooth and the underlying bone. In addition to modeling the periodontal ligament (PDL) as a continuous structure as considered in previous studies, the PDL is modeled more accurately in a novel fashion as a fibrous structure. The results indicate that the type of PDL modeling has a significant effect on the nature and magnitude of alveolar stresses, and that the fibrous PDL modeling shows higher and more widely distributed lateral tensile stresses in the alveolar bone than those resulting from the continuous PDL modeling.

Alveolar Process↗
PubMed1981

Effect of K2SO4 and CaSO4 dihydrate solutions on crystallization and strength of gypsum.

Crystal formation obtained from evaporating clear filtrates of dental stone mixed with various solutions were examined with an optical and scanning electron microscope. It was found that when K2SO4 was present in any concentration, a spherulitic structure dissimilar to that of CaSO4. 2H2O and K2SO4 was dominant. It is concluded that syngenite (a complex compound of CaSO4 and K2SO4) forms at the center of the nuclei of crystallization and is responsible for spherulitic formation. The use of K2SO4 solution and saturated CaSO4 solution was also found to improve the strength both at one and 24 h.

Calcium Sulfate↗
PubMed1980

Integration of the basic, behavioral, and biomaterials sciences with the clinical curriculum.

An approach to effective integration of the basic, behavioral, and biomaterials sciences with the clinical curriculum is described. Teaching is accomplished by both scientists and clinicians on multidisciplinary teams. The instructional format is based on terminal objectives that are stated in behavioral terms. Examples of the objectives and the manner in which they are fulfilled are presented.

Behavioral Sciences↗
PubMed1979

Stress analysis of single-tooth implants. I. Effect of elastic parameters and geometry of implant.

Five different implant materials and three different geometries of ankylosed single-tooth implants were investigated. The stress distributions within and around the implants were determined by finite element analysis. Results show that the optimal combination of implant material and geometry can reduce implant and alveolar stresses by a factor of three when compared to an arbitrary implant design.

Alveolar Process↗