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Biomedical subjects

R E Smith

Publications and source records attributed to R E Smith.

At least 289 records · Page 16Linked to original sources
PubMed1988

The lipids of chalazia.

The tissue contents of chalazia taken from five individuals were extracted for lipids and analyzed by TLC and GLC. Lipids found were sterol esters 9%, wax esters 0%, triacyl glycerols 4%, free cholesterol 11%, free fatty acids 2%, unidentified nonpolar material 3%, ceramides 7%, cerebrosides 3%, phosphatidyl ethanolamine 12%, phosphatidyl choline 20%, sphingomyelin 4%, lysolecithin 4%, unidentified polar material 18.0%. GLC of the sterol esters gave peaks corresponding to the C14, C16, C18 and C20 normal fatty acid esters of cholesterol. The free fatty acids were also of the normal kind. Thus, the lipids of chalazia contents show little similarity to the lipids of the meibomian gland. The latter has a large component of sterol esters and wax esters. Also the fatty acids of all the meibomian gland ester lipids have significant amounts of iso- and anteisobranching in contrast to the chalazia lipids. Chalazia lipids more closely resemble the lipids of membranes of phagocytic cells with a large cholesterol content.

Adolescent↗
PubMed1987

Association of persistent synthesis of viral DNA with macrophage accessory cell dysfunction induced by avian retrovirus myeloblastosis-associated virus of subgroup B inducing osteopetrosis in chickens.

This investigation concentrates on a regenerative anemia and immunosuppression occurring in the absence of osteopetrosis. Polyclonal activation of T-cells was used as an in vitro test system to study immunosuppression induced by the avian myeloblastosis-associated virus of Subgroup B inducing osteopetrosis [MAV-2(O)]. T-cell unresponsiveness in vitro was attributed to a defect in an accessory cell function of the macrophage. Counterflow centrifugation fractionation followed by mixing experiments indicated that the T-cell population from immunosuppressed chickens responded to mitogen stimulation when added to control macrophage cultures. In addition, lymphocyte fractions from uninfected chickens were unresponsive when added to macrophage cultures isolated from MAV-2(O)-infected chickens. Cultured splenic macrophages isolated from infected chickens contained high levels of both integrated and unintegrated viral DNA and formed syncytia by 21 days in culture. The macrophages remained viable and exhibited mature functional characteristics during mitogen stimulation assays. Therefore, it was speculated that the persistent synthesis of retrovirus DNA might be involved in the inability of infected macrophages to function as accessory cells.

Animals↗
PubMed1987

The significance of the pars plana exudate in pars planitis.

We divided 61 patients (111 eyes) with pars planitis into three groups based on clinical appearance. Patients in Group I had bilateral vitreous cells and bilateral pars plana exudates (36 patients, 72 eyes); patients in Group II had bilateral vitreous cells but a pars plana exudate in one eye only (14 patients, 28 eyes); and patients in Group III had vitreous cells and exudate formation in the single eye involved (11 patients, 11 eyes). The presence of a pars plana exudate was associated with more severe vitreous disease and increased incidence of cystoid macular edema.

Adult↗
PubMed1987

Proliferative fibromatosis in avian skeletal muscle caused by cloned recombinant avian leukosis viruses.

Two molecular recombinants (EU-8 and K-3) constructed from ring-necked pheasant virus and UR2AV, the helper virus associated with avian sarcoma virus UR2, caused a high incidence of a hitherto unreported pathological condition in chick skeletal muscle. A disease spectrum was observed in which muscle was infiltrated by proliferating fibroblasts and caused white streaks, white diffuse areas, or well-defined elongated tumors. Fibroblast proliferation was progressive, and the gross presentation depended on the rapidity and extent of proliferation. There was evidence of anaplasia but not frankly malignant disease or metastases. The disease was produced at a high frequency when 10-day-old embryos were infected. Breast muscle (pectoralis major and minor) was affected with variable severity in all birds, thigh muscles were affected occasionally, while other thoracic, external abdominal, and wing muscles were affected very rarely. Progression of proliferative muscle lesions was demonstrated by sequential necropsies and microscopic examination of muscle samples. The disease appeared before 2 weeks of age, and thin white streaks with minimal cellular proliferation were the earliest lesions observed. Elongated, spindle-shaped tumors were the most advanced form of proliferation observed. The advanced lesions showed cellular anaplasia and signs of rapid growth, and appeared most commonly at 6 weeks of age or later. Histologically, mild proliferation correlated with normal appearing fibroblasts producing collagen. Severe proliferation correlated with anaplastic, rapidly dividing cells producing little collagen and a high mitotic index. A decrease in the virus dose resulted in less severe fibromatosis, but at least one chicken infected with a low virus dose showed severe disease. When 10- or 35-day-old hatched chicks were injected in the breast muscle with EU-8 or K-3, a low incidence of lymphoid leukosis was observed, but no fibromatosis resulted during an observation period of 27 weeks. Infectious virus was extracted from the fibromatosis in the breast muscle, and extracted virus caused the same disease when injected in 10-day-old embryos. No transforming activity was observed on normal chick embryo fibroblast monolayers. Cell cultures were established from areas in the breast muscle affected by fibromatosis, and from discrete tumors. These cells did not show any signs of transformation in culture. Supernatants obtained from these cell cultures caused fibromatosis when injected into 10-day-old embryos, but did not transform normal chick embryo fibroblasts.

Animals↗
PubMed1987

Cytomegalovirus retinitis as the initial manifestation of the acquired immune deficiency syndrome.

We studied eight patients in whom cytomegalovirus retinitis was an initial manifestation of AIDS. Six of these patients had cytomegalovirus retinitis alone at the time of diagnosis and two patients had simultaneous cytomegalovirus retinitis with other AIDS associated diseases (Kaposi's sarcoma in one patient and cytomegalovirus colitis in one patient). Treatment with ganciclovir (dihydroxy propoxymethyl guanine), a new antiviral medication related to acyclovir, resulted in regression of retinitis in all five patients treated with this drug. Our study shows that cytomegalovirus retinitis may be the initial manifestation of AIDS and that ganciclovir is a clinically effective antiviral agent for cytomegalovirus.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Echographic localization of corticosteroids after periocular injection.

The location of repository corticosteroid after subtenon injection was determined in 24 patients with macular edema associated with uveitis or anterior segment surgery. Standardized A-scan and B-scan echography were performed immediately before and after each injection. Localization was compared after subtenon injection in either the superior or inferior temporal quadrants. Echography showed that corticosteroid was deposited within the subtenon space over the macula in 11 of 24 cases. The therapeutic response manifested by improvement in macular function may be related to the proximity of the corticosteroid to the macular area. Lack of therapeutic response to repository corticosteroids may be because of placement at a site relatively far from the target zone.

Adrenal Cortex Hormones↗
PubMed1987

Changing patterns of uveitis.

We conducted a retrospective analysis of 600 patients with uveitis seen at the Estelle Doheny Eye Center to determine the frequency of occurrence of the various forms of uveitis and to see if the causes of uveitis have changed as compared with previous studies. In 402 cases (67.0%) we established a specific diagnosis based on history, physical findings, and laboratory studies: 167 cases (27.8%) involved primarily the anterior segment, 230 (38.4%) the posterior segment, and 111 (18.4%) occurred as panuveitis. Intermediate uveitis (pars planitis) was the single most frequently diagnosed uveitic entity and accounted for 92 cases (15.4%). We compared our findings with those of previously published studies and found that, as new diseases occur and improved diagnostic techniques become available, the differential diagnosis of uveitis continues to change.

Choroiditis↗
PubMed1987

The intraocular environment and experimental anaerobic bacterial endophthalmitis.

Anaerobic bacteria are prevalent in conjunctival flora but have not been adequately investigated as possible causes of endophthalmitis. The mean oxidation-reduction potential (Eh) of the rabbit vitreous was found to be +25.1 mV, well within the limiting Eh value of many anaerobes. There was an oxygen pressure gradient in the vitreous ranging from 2.1 mm Hg immediately posterior to the lens to approximately 20 mm Hg adjacent to the medullary ray. Endophthalmitis was produced with pure cultures of Fusobacterium necrophorum, Propionibacterium acnes, and Peptostreptococcus magnus. Relatively small inoculates of F necrophorum caused severe, acute endophthalmitis with scleral perforation; P acnes and P magnus produced a self-limited endophthalmitis; and vitreoretinal fibrosis was a sequela of the Propionibacterium acnes infection.

Animals↗
PubMed1987

Osteonecrosis in a patient with immune thrombocytopenic purpura.

We report a case of osteonecrosis in a 26-year-old woman treated with prednisone for immune thrombocytopenic purpura. The unusual complication occurred after a much shorter course of steroids of a considerably smaller cumulative dose than in previously reported cases.

Adult↗
PubMed1987

Decontamination of Campylobacter jejuni on chicken drumsticks using chemicals and radiation.

A trial was conducted to compare the efficacy of four disinfectants and radiation to reduce the level of C. jejuni contamination on poultry meat. Two levels of each treatment were applied to chicken drumsticks inoculated with a known concentration of a strain of Campylobacter jejuni, biotype 1, isolated from a human patient with diarrhea. Radiation using a cobalt-60 source at a level of 0.5 KGy effected a 99% surface reduction in C. jejuni. With a mean initial surface contamination level of 1.1 X 10(3) Colony Forming Units/cm2, 1 KGy completely eliminated C. jejuni. Glutaraldehyde at 0.5% concentration for 30 minutes had an efficacy similar to the lower dose of radiation. Chlorine showed a negligible effect on C. jejuni. Succinic acid and Poly (hexamethylenebiguanide hydrochloride) were statistically similar in their effectiveness, ranking between glutaraldehyde and chlorine. These results strongly indicate that, of the alternatives tested, low-dose radiation is the method of choice for reducing Campylobacter contamination of poultry products.

Animals↗
PubMed1987

An electronic processor for use with a whole body plethysmograph to determine specific airways conductance.

The panting manoeuvre traces produced by a whole body plethysmograph during the measurement of specific airways conductance (sGaw) are traditionally analysed by hand. Since this technique is tedious and time consuming it is prone to error, as well as suffering from considerable inter-observer variability. We describe a new inexpensive analogue electronic processor which rapidly produces readouts of sGaw and overcomes many of the problems associated with hand analysis. The system takes as its inputs the mouth flow and plethysmograph volume outputs from a pressure-corrected flow-displacement whole body plethysmograph, but it could be adapted for use with other types of plethysmograph. Since the processor is intended mainly for use during serial measurements of sGaw it does not carry out an unnecessary correction for flowmeter resistance. Using an electronic simulator of sGaw signals the output of the processor was found to be linear to better than 2% of full scale and to be insensitive to drift on the volume signal. The system has been comprehensively evaluated using signals from both normal subjects and patients. The processor output was found to agree well with the results of hand analysis, an agreement which was comparable with that obtained from computer based systems. For the normal subjects the equal value line adequately described the relationship between the processor and hand estimates of sGaw. However, for patients the slope of the best fit line was 18% less than unity but the correlation coefficient was high: 0.95. Reproducibility was found to be better than 3%.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMed1987

Effect of Rous associated virus number 7 on lymphoid cells and tissues of the chicken.

Infection of chicks or chick embryos with Rous associated virus number 7 (RAV-7) led to a decreased blastogenic response to Concanavalin A (Con A) by lymphocytes isolated from the spleen and thymus. Chicks infected with RAV-7 8 days after hatch manifested decreased Con A blastogenesis 5 weeks postinfection, while chicks infected in ovo at 10 days of incubation showed an unusual pattern of cell density dependent decreased blastogenesis two weeks post-hatch (three weeks post-infection). Histopathological examination of tissues from RAV-7 infected chicks revealed evidence of lymphoid organ involution and widespread lymphoproliferative lesions by 3 weeks of age. The combination of decreased in vitro lymphoid blastogenesis and in vivo lymphoproliferation suggests that RAV-7 interacts with lymphocytes in a fashion that has not previously been described in the chicken.

Animals↗
PubMed1987

Quantitative evaluation of arterial pulsatile flow and pressure, applying impedance plethysmography to a human arterial model incorporating anatomical branching and scale.

This paper presents the theoretical basis of a new noninvasive method for obtaining arterial pulsatile flow and pressure. The proposed technique uses a model of the human arterial system based on the anatomical branching structure of the arterial tree. Arteries are divided into segments represented by uniform thin-walled elastic tubes with realistic arterial dimensions and wall properties. A simple mathematical model equivalent to electrical transmission lines is developed which is able to fit the electrical impedance plethysmograph waveform produced by the subjects throughout the complete cardiac cycle. Ensemble averaging is suggested as an option for processing of the impedance data. This technique provides artifact-free impedance data which enables the model to be used during exercise as well as quiet breathing. The proposed model provides an enhanced capability for measuring pulsatile blood flow and pressure in both clinical and research applications.

Arteries↗
PubMed1987

Vaccination of cattle with chemically modified and unmodified salt-extractable proteins from Brucella abortus.

Beef heifers were vaccinated on Day 0 with either salt-extractable protein (CSP) or chemically modified CSP (dCSP) from Brucella abortus Strain 19 in Freund's complete adjuvant (FCA). Six weeks later, vaccination was repeated, and heifers received either the homologous or heterologous vaccine. Another group of heifers received only FCA and saline. Vaccinations with CSP or dCSP stimulated marked antibody responses to B. abortus, as detected by standard serologic tests, an enzyme-linked immunosorbent assay, or a quantitative fluorometric immunoassay. Twelve percent of the heifers were seropositive by the CARD test 1 year after vaccination. Vaccination stimulated an increased cell-mediated immune response as measured by lymphocyte blast transformation (LBT) to B. abortus antigens. Fifty-six weeks after the initial vaccination, the heifers were challenged intraconjunctivally with 1.9 X 10(7) colony-forming units of B. abortus strain 2308. Sixty to 83% of the heifers aborted in each group and 70-83% of the heifers were culture positive. There were no significant differences (P greater than 0.05) among groups with respect to the number of abortions or the number of culture-positive heifers. Antibody responses increased rapidly within 4 weeks after challenge. Overall, antibody responses were greater for heifers that aborted than for those that did not abort. These differences were significant (P less than 0.05) only as measured by the fluorometric procedure. The LBT responses appeared to be higher for vaccinates than for the control group, but these differences were not significant (P greater than 0.20). There was a significantly lower (P less than 0.05) LBT response to heat-killed B. abortus in those heifers that aborted compared to those that did not.

Abortion, Veterinary↗
PubMed1987

A sequential study of bone lesions caused by isolates of an avian osteopetrosis virus, MAV-2(0).

The pathogenesis of avian osteopetrosis caused by rapid and slow-onset isolates of myeloblastosis associated virus, MAV-2(0), was studied by inoculation of 10-day-old chick embryos with virus. Femur and calvarium were examined at 15, 17 and 19 days in ovo and 7 and 25 days after hatching by histologic and immunoperoxidase techniques. Femur and calvarium were also examined by electron microscopy at 17 and 19 days in ovo and at 7 days after hatching. Avian osteopetrotic bone lesions were characterized by exuberant periosteal proliferation; the time of onset varied with different virus isolates. In the femur virus was first associated with osteoprogenitor cells, then with osteoblasts and finally with osteocytes as the cells progressed through normal sequences of differentiation. The amount of virus produced by these cells did not correlate with onset of periosteal proliferation. Slow onset isolates provoked early virus production, but proliferative lesions did not develop until later. Conversely, the rapid onset isolate induced little early virus production, although lesions were present. Periosteal proliferation was associated with and preceded by perivascular edema and perivascular cell necrosis within the bone cortex following infection by all isolates. However, the rapid onset isolate caused more severe lesions than other isolates. These lesions included vascular thrombosis, capillary necrosis and focal bone necrosis. The relationship between early vascular lesions and late periosteal proliferation seen with the slow onset isolates is not as clear as with the rapid onset isolate. Calvarial bone, a representative flat bone, was found to have virus present, but at a level less than the femur. Vascular lesions were rarely seen in the calvarium and bone proliferation did not occur at this site.

Animals↗