Search PubMed⌕ Search

Biomedical subjects

D Crawford

Publications and source records attributed to D Crawford.

122 records · Page 7Linked to original sources
PubMed1980

Electron microscopy applied to studies of the biological significance of defects in crocidolite asbestos.

Transmission electron microscopy is used in an investigation of crocidolite asbestos associated with two biological systems. Control material is extremely defective and contains in particular an abundance of Wadsley defects, (100) planar faults, and pores. Fibres sectioned in lung tissue and fibres taken from in vitro exposure to blood serum show evidence of erosion by two mechanisms--preferential attack at (100) planar defects and general surface dissolution.

Animals↗
PubMed1979

The small bowel tumor problem: an assessment based on a 20 year experience with 116 cases.

Documented rarity, diagnostic difficulty and poor results stimulated this study of 79 malignant and 37 benign small bowel tumors in order to emphasize these lesions, determine their symptomatology and improve diagnosis and results, particularly in the malignant group. Chief symptoms were recurrent abdominal pain and tenderness, signs of obstruction and gastrointestinal bleeding. Fourteen cases were asymptomatic. The mean symptom-diagnosis interval was 6.6 months. Roentgenographic contrast studies were helpful in diagnosing 33 of 43 patients, with false negatives in 10. Laboratory studies were usually not helpful. Metastases were present at the time of surgery in approximately 58%. In the malignant group curative procedures were performed in 36 and palliative in 43, with an operative mortality of 10%. Five and 10 year survival rates were respectively 21/51 (41.2%) and 8/38 (21.2%) for malignancies. Individual 5 and 10 year survival rates were respectively as follows: carcinoid 11/15, 4/8; undifferentiated carcinoma 3/5, 1/3; lymphoma 3/11, 1/9; leiomyosarcoma 2/7, 1/6 and adenocarcinoma 2/13, 1/12. In the benign group results were excellent, except for one death from pulmonary embolism. The study suggests that if results with malignant small bowel tumors are to be improved, prompt diagnostic study and early consideration of laparotomy in patients with suggestive symptoms is mandatory.

Adenocarcinoma↗
PubMed1977

Inhibition of the in vitro outgrowth of Epstein-Barr virus-transformed lymphocytes by thymus-dependent lymphocytes from infectious mononucleosis patients.

Known numbers of thymus-dependent (T) lymphocytes, obtained by positive selection from the blood of acute infectious mononucleosis (IM) patients and from control donors, were added to target cultures of foetal mononuclear cells within 0-7 days of exposure of the target cells to one of a range of doses of Epstein-Barr (EB) virus. The subsequent outgrowth of virus-transformed foetal cells was markedly inhibited by the presence in the cultures of IM-derived T cells, whilst similar numbers of T cells prepared either from cord blood or from adult donors seronegative for EB virus had little or no inhibitory effect. Target foetal cells treated with papain to remove any viral envelope material remaining on the cell surface after infection, were just as sensitive as untreated cells to the addition of IM-derived T cells. It is concluded that the inhibition cannot be mediated through recognition either of viral envelope structures on the surface of infected cells or of the antigenically related virus-determined membrane antigen, MA, but must depend upon recognition of the lymphocyte-detected membrane antigen, LYDMA. The regularity with which IM-derived T cells block the outgrowth of virus-transformed foetal cells suggests that LYDMA consistently appears on the surface of infected foetal cells before the establishment of transformed foci, but is unlikely to be directly associated with the cells' existing histocompatibility antigens.

Antigens, Viral↗
PubMedDate not supplied

Studies on the use of a long-acting oxytetracycline in turkeys: efficacy against experimental infections with Alcaligenes faecalis and Pasteurella multocida.

A group of 2-week-old turkey poults was inoculated with a pathogenic strain of Alcaligenes faecalis. One week later, half the group was injected with a long-acting oxytetracycline formulation. Poults were examined post-mortem on days 3, 5, and 10 post-treatment. Swabs were taken of the trachea, sinus, and lung of each poult. Poults were observed closely for clinical signs, and appropriate tissues were taken for histopathology. Results showed no evidence of therapeutic effect on A. faecalis infection in vivo, even though the organism was highly sensitive in vitro. Six-week-old turkeys were inoculated intramuscularly with 3.7 X 10(3) organisms of the P-1059 strain of Pasteurella multocida. Immediately following inoculation, half the group was treated with the long-acting oxytetracycline. Ninety percent of the untreated poults were dead 72 hours postinoculation, whereas none of the treated turkeys died. No evidence of any clinical disease was observed in the treated group during the 8-day observation period. The long-acting oxytetracycline product was highly efficacious in preventing disease caused by experimental inoculation with the P-1059 strain of P. multocida.

Alcaligenes↗
PubMedDate not supplied

Clinical applicability of bioelectric impedance to measure body composition in health and disease.

The applicability of bioelectric impedance analysis (BIA) as a measure of body composition in children and young adults in both health and disease was studied in 155 subjects (5 mo to 54 yr of age) who were healthy (n = 21), had cystic fibrosis (n = 16), or had end-stage liver disease with variable clinical ascites or edema (n = 62). BIA and phase angle measured at a frequency of 50 kHz between the wrist and contralateral ankle by use of a tetrapolar measuring technique was compared with fat-free mass (FFM) estimated from skin-fold (SK) thickness measurements (n = 57), and body cell mass (grams potassium) measured by total-body potassium (TBK) counting. In a subgroup of subjects with end-stage liver disease, BIA was compared with total-body water measured by deuterium dilution (n = 21). High levels of correlation were found in healthy subjects, cystic fibrosis patients, and patients with end-stage liver disease when impedance (height2/resistance) was used to predict TBK (r = 0.96, 0.96, 0.98, respectively), and SK was used to predict FFMs (r = 0.96, 0.99, 0.90, respectively), by linear regression analysis. However, less satisfactory relationships were found when the methods were more appropriately analyzed with an estimated limits of agreement procedure (1 SD = 8.5, 5.0, 27.7% [TBK] and 9.4, 6.7, 23.0% [FFMs], respectively). A poor level of technique agreement (1 SD = 14%) was found when this method was compared with total-body water measured by isotope dilution in patients with liver disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗