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Biomedical subjects

S D Cook

Publications and source records attributed to S D Cook.

At least 289 records · Page 16Linked to original sources
PubMed1980

Implant-bone interface characteristics of bioglass dental implants.

Three-dimensional finite element analysis (FEA) has been used to determine the implant-bone interface characteristics of bioglass dental implants. The results of the FEA were verified by comparison with the results of mechanical testing performed on animal implant specimens. The results of the study showed that the assumption of a discontinuous change of elastic properties at the bone-implant interface was a poor assumption for the bioglass implants. Interface elastic moduli of 354.0, 155.0, and 47.0 MPa for conditions of 25, 50, and 100% tissue attachment were determined for the bioglass implants.

Animals↗
PubMed1980

The influence of design parameters on calcar stresses following femoral head arthroplasty.

A two-dimensional finite element model (FEM) was used to investigate the effect of various prosthesis design parameters on stresses along the proximal medial aspect of the femur. Strain calculations were compared to reported experimentally measured strains for an intact femur and femur containing a prosthesis in an effort to verify the FEM results. The results of the study indicated that stress levels in the medial aspect of the femur approaching those of the intact femur are possible with a device having an elastic modulus similar to bone. It was found that acrylic bone cement had little effect on stress profiles in the medial aspect when compared to stresses for devices utilizing a direct bone to implant attachment mechanism. It was also found that reduction in implant stem length and elastic modulus of tissue present at the prosthesis--bone interface could be used to increase stresses in the medial aspect; however, their effects were not as dramatic as reducing the elastic modulus of the stem material.

Arthroplasty↗
PubMed1980

Multiple sclerosis and distemper in Iceland 1966-1978.

A highly restricted epidemic of canine distemper occurred in southwest Iceland in 1966-67. We have determined the extent of dog contact and exposure to dogs during the distemper epidemic in Icelandic MS patients with onset since 1966. Further, age of onset, and annual incidence of MS from 1966 through 1978 have been determined. Thirty-five of 36 MS patients had close dog contact prior to onset of their illness, and 34 were in the area of the distemper epidemic during 1966-67. A significant decrease in age of onset of MS (31.6 to 26.5) from 1956-1965 to 1967-1978 was noted, consistent with exposure of a susceptible cohort to a point infection with a varible incubation period. A review of incidence of MS in the 10-year periods after distemper epidemics in Iceland in 1921-1922, and 1941-1942 reveal significantly more MS than in comparable time periods before these epidemics. These collective findings are consistent with, but do not prove, a relationship between dogs, distemper and MS.

Adolescent↗
PubMed1980

Possible beneficial effect of high-dose intravenous steroid therapy in acute demyelinating disease and transverse myelitis.

Intravenous steroid followed by oral prednisone was administered to patients with Guillain-Barré syndrome (five), acute transverse myelitis (three), and multiple sclerosis in acute relapse (seven). Preliminary experience with each of these disorders revealed prompt clinical improvement in some patients. The approach used in this uncontrolled study deserves further investigation.

Acute Disease↗
PubMed1980

Multiple sclerosis and viruses: an overview.

The evidence for a viral etiology of MS has been reviewed. The strongest evidence favoring a virus is based primarily on epidemiologic considerations. Less convincing evidence comes from pathologic studies, serology, lymphocyte reactivity to viral antigens, and reports of identification of virus in MS tissues. Animal models of viral demyelination exist, which may provide insight into possible etiologic agents and pathogenetic mechanisms. Considering all the data, it is clear that no agent can be convincingly linked to MS at the present time. If a single virus causes the majority of cases of MS, then a morbilliform virus--canine distemper--is a leading contender, because this agent is consistent with the epidemiologic and serologic findings and is highly neurovirulent for animals ranging from mice to primates. Since no virus fulfills the usual criteria for linking an infectious agent to a disease, other possibilities must be considered. If MS is caused by a single virus, it may be a common virus not presently considered as being associated with MS, or an agent as yet unidentified. It is also conceivable that multiple agents, acting alone or in concert, initiate the MS process, perhaps through a common immune-mediated pathway. In this regard, another human demyelinating disease--the Guillain-Barré syndrome--which may in some instances become a chronic remitting and relapsing disorder, is thought to be initiated by multiple infectious agents but to have an immunologic pathogenesis.

Animals↗
PubMed1979

Neutralizing antibodies to canine distemper and measles virus in multiple sclerosis.

Serum neutralizing antibody to canine distemper virus (CDV) was measured in 142 patients with multiple sclerosis (MS), an equal number of age and sex-matched normal controls, and 75 patients with other neurological disorders. An elevated antibody titer was found in the MS population compared to controls. Measles-neutralizing antibody was also found to be elevated in 128 patients with MS. The mean ratio of measles to CDV antibody was similar in the control and MS groups, but a wide range of measles to CDV ratios was found in individual patients and controls. No significant correlation was found between IgG levels and neutralizing antibody titers in MS sera. While the increased titer of measles and CDV antibody may represent a non-specific immunological response, these findings are also consistent with the hypothesis that CDV or a closely related measles virus may stimulate the increased level of measles and CDV antibodies found in MS sera.

Adolescent↗
PubMed1978

Further evidence of a possible association between house dogs and multiple sclerosis.

The present study was undertaken because of the recent report of an association between familial multiple sclerosis (MS) and prior ownership of a small pet. Forty-five patients with sporadic MS were retrospectively compared with 45 closely matched controls and were found to have owned a significantly greater number of indoor dogs prior to the onset of MS. Importantly, the MS patients had also had more exposure to neurologically ill dogs in the five years before the onset of symptoms. These new data further support the hypothesis that house dogs may serve as an animal vector in MS.

Animals↗
PubMed1977

Guillain-Barré syndrome in Greater New York-New Jersey.

Epidemiologic data on 176 patients with acute Guillain-Barré syndrome observed over a nine-year period in the New York-New Jersey metropolitan area are presented. A striking predilection for patients aged 16 to 25 years, with a second lesser peak between ages 45 to 60, was found. Seasonal clustering of patients occurred, with nearly half the patients afflicted during the four-month period of late summer and fall. The distribution between men and women was equal. In this series 23% of the patients required tracheostomy, and 5% had a fatal course.

Acute Disease↗
PubMed1977

A possible association between house pets and multiple sclerosis.

29 patients with multiple sclerosis (M.S.) from families in New Jersey believed to have more than 1 member with this disease and 29 controls matched for age, sex, neighbourhood, and socio-economic status were questioned about their ownership of pets. No difference in ownership of cats or dogs was found. Exposure to small indoor pets (cats or dogs), however, was significantly higher in the M.S. group (P less than 0-001). Exposure to small indoor pets was particularly striking during the ten years before onset of initial symptoms of M.S. when the M.S. group was compared to the control group (P less than 0.01). 33 of 49 M.S. patients in these families had a cat or dog in the house within one year before onset of the first neurological symptom. 3 families had more than 1 member in whom initial symptoms of M.S. developed in the same year despite wide age ranges. These results suggest that exposure to house pets may sometimes be associated with subsequent M.S. Our findings should be interpreted with caution until they are confirmed by others.

Adult↗
PubMed1976

Disease markers in acute multiple sclerosis.

Three serum components that are known to become elevated during inflammation and tissue destruction, C-reactive protein, C3 proactivator, and orosomucoid, which are acute phase reactants, and serum lgM were measured in patients with multiple sclerosis (MS) hospitalized with acute exacerbations. Significantly elevated levels of one or more of these serum components were found in 12 of 13 patients with clinically active MS. Serial studies in two patients revealed that clinical improvement was accompanied by a decline in the serum levels of these factors. These findings suggest that measurement of these serum proteins may be of value in assessing progress of disease activity in MS patients.

Acute Disease↗