Search PubMed⌕ Search

Biomedical subjects

J M Gilbert

Publications and source records attributed to J M Gilbert.

At least 109 records · Page 6Linked to original sources
PubMed1976

Evidence for the synthesis of tubulin on membrane-bound and free ribosomes from rat forebrain.

Evidence is presented that tubulin is synthesized in cell-free systems derived from rat forebrain containing either membrane-bound or free ribosomes. Both systems were supplemented with saturating amounts of messenger RNA (from either membrane-bound of free ribosomes) and soluble enzyme and initiation factors from whole forebrain. Synthesized products were chracterized by two biochemical purification methods for brain tubulin isolation. These methods of tubulin analysis indicated that both cell free systems synthesized the same relative amounts of tubulin.

Animals↗
PubMed1975

Comparison of ribosomal proteins from neoplastic and non-neoplastic cells. Resolution by two-dimensional gel electrophoresis.

Functionally active mammalian membrane-free ribosomes were prepared from rat forebrain, a solid tumor (mouse neuroblastoma C-1300) and a human tumor cell-line in suspension culture (HeLa). Proteins were extracted from these ribosomes and were resolved by a newly developed. Two dimensional gel electrophoretic procedure. Although the ribosomal protein patterns from the three preparations were generally similar, there were four obvious differences between the forebrain ribosomes and the ribosomes from the two neoplastic cell types.

Animals↗
PubMed1972

Separation of reticulocyte initiation factor M 2 activity into two components.

IF-M(2), one of three initiation factors isolated by DEAE-cellulose chromatography from the 0.5 M KCl-wash fraction of rabbit reticulocyte ribosomes, has been separated by Sephadex G-200 chromatography into two components: IF-M(2A) and IF-M(2B). IF-M(2A) elutes near the void-volume, while IF-M(2B), which is much smaller in molecular weight than IF-M(2A), elutes slightly after a hemoglobin marker. In the presence of the other appropriate factors, both IF-M(2A) and IF-M(2B) are required to stimulate poly(U)-directed polyphenylalanine synthesis at low Mg(++) concentration, ApUpG-directed Met-tRNA(F) binding to washed reticulocyte ribosomes, and initiation of globin synthesis from endogenous mRNA. IF-M(2A) stimulates ribosome-dependent GTP hydrolysis, while IF-M(2B) does not; IF-M(2B) stimulates ApUpG-directed fMet-tRNA(F) binding in the presence of IF-M(1), while IF-M(2A) does not. Although IF-M(2A) and IF-M(2B) can be distinguished from each other by size and by activity, a distinct function for IF-M(2B) has not yet been found. Therefore, its precise role in the initiation process remains unclear.

Animals↗
PubMed1970

Cell-free hemoglobin synthesis in beta-thalassemia.

Human ribosomes obtained from the reticulocytes of patients having either homozygous beta-thalassemia (thalassemia ribosomes) or a hematological disorder unrelated to thalassemia ("normal" ribosomes) have been utilized in a cell-free system highly active in the synthesis of intact human globin chains. This system is dependent on the addition of a ribosomal wash fraction from reticulocytes that contains factors necessary for chain initiation. In response to the ribosomal wash fraction, isolated from either thalassemia, normal human, or rabbit reticulocytes, normal human ribosomes synthesize equal amounts of alpha and beta chains. In contrast, in response to all three types of ribosomal wash fractions, thalassemia ribosomes synthesize 8-times more alpha than beta chains, a ratio similar to that produced in the intact cells of these patients. The molecular defect in beta-thalassemia, therefore, does not appear to be associated with initiation factors.

Anemia, Hemolytic, Autoimmune↗
PubMedDate not supplied

Distribution of metastases at necropsy in colorectal cancer.

A series of 372 necropsies on patients with colorectal cancer (CRC) was examined retrospectively. Patients were excluded if the primary tumour was not removed, if the operation was palliative or if death occurred within three months of operation. Only 43 cases remained after these exclusions and of these six died of intercurrent disease. The 37 remaining patients were all thought to have undergone a curative resection, following which they died with recurrent tumour. They represent the group of patients who might have benefited from adjuvant chemotherapy. The pattern of metastases and the cause of death was examined in these 37 patients. Local recurrence was found more commonly (25 cases, 68 per cent) than hepatic metastases (21 cases, 57 per cent) or metastases at other sites. This finding indicates that excision of the primary tumour must be as complete as possible and that adjuvant therapies must be directed both locally as well as systemically.

Adult↗
PubMedDate not supplied

Prospective serial liver ultrasound scanning in resectable colorectal cancer treated with adjuvant razoxane.

Prospective serial ultrasound scanning (U/S) of the liver at 3-monthly intervals has been used to detect the presence of hepatic metastases from successfully resected Dukes' A, B and C grade colorectal carcinomas in a trial of the antimetastatic agent razoxane (ICRF 159). One hundred and twenty-six consecutive patients were randomly allocated to either adjuvant razoxane treatment (61) or to no further treatment (65). Twenty-six patients, 15 in the control group (23 per cent) and 11 in the razoxane treatment group (18 per cent) have developed hepatic metastases. All but three patients in the treated group and four in the controls were detected by U/S. In the control group four patients had definite metastases when metastases were first seen by ultrasound and three more, among the eight who initially had probable metastases, became definite metastases on ultrasound. In the treated group four patients had definite metastases and four more developed them amongst 12 who had probable metastases. The remaining eight of these 12 all regressed completely. This compared with only one complete regression (additionally on 5-FU for lung secondaries) amongst the eight controls who had probable metastases. The median time to development of liver metastases detected by U/S and other means was 59 weeks in the control group and 91 weeks in the razoxane treatment group. Ultrasound has proved to be a safe, sensitive and acceptable serial imaging technique for detecting colorectal liver metastases. Used prospectively, U/S has been valuable in monitoring the natural history of liver metastases and their behaviour during razoxane treatment.

Colonic Neoplasms↗
PubMedDate not supplied

Effects of Eimeria brunetti infection and dietary zinc on experimental induction of necrotic enteritis in broiler chickens.

Broilers infected with Eimeria brunetti and given dietary zinc were examined for experimental induction of necrotic enteritis. Inoculation with sporulated E. brunetti oocysts at 7 days of age was followed by 5 consecutive days of oral inoculation with cultured Clostridium perfringens. Feed was supplemented with zinc at 1000 ppm. Upon necropsy of broilers 6 days after coccidial inoculation, necrotic enteritis was found in 20% (2/10) of birds given both organisms and dietary zinc. Coccidial lesion scores were also highest in that group. Birds infected with E. brunetti and C. perfringens with no dietary zinc had significantly higher coccidiosis lesion scores (P less than 0.05) than groups inoculated with E. brunetti only, regardless of zinc supplementation. Alpha toxin levels in intestinal contents were low in groups infected with both organisms, regardless of zinc supplementation. Zinc was tested for effects of alpha toxin production in vitro. In the mid-log phase (6 hours incubation), a high level of alpha toxin was produced in zinc-supplemented media, but this was lost quickly in the presence of trypsin. Addition of zinc partly protected the toxin from the action of trypsin.

Animal Feed↗
PubMedDate not supplied

An enzyme-linked immunosorbent assay for coccidiosis in chickens: correlation of antibody levels with prior exposure to coccidia in the laboratory and in the field.

An enzyme-linked immunosorbent assay was developed for detecting antibody to coccidia to facilitate the survey of laboratory and field infections. Serum antibody levels in chickens were measured against soluble Eimeria tenella oocyst antigen. Sera from breeders aged 10, 23, 37, and 43 weeks were positive with uniformly high antibody titers. Broiler chick sera showed high maternal antibody titer at hatch, decreasing to an almost negligible response at 3 weeks of age. Two-week-old broiler chicks had variable responses to a single infection of E. tenella: titers were elevated at 8 to 10 days postinfection and generally increased through day 24. Weekly reinfection of 2-week-old broiler chickens produced an antibody titer in proportion to the number of oocysts per dose and stimulated protection against challenge with 2 x 10(5) E. tenella. Inbred birds raised in a pathogen-free environment for 6 weeks had no detectable antibody titers.

Aging↗