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Biomedical subjects

J C Thomas

Publications and source records attributed to J C Thomas.

At least 91 records · Page 5Linked to original sources
PubMed1989

Expression of DNA binding proteins in carrot somatic embryos that specifically interact with a cis regulatory element of the French bean phaseolin gene.

Nuclear proteins from bean (Phaseolus vulgarus) embryos bind specifically to a 55 bp DNA sequence located upstream of the seed storage protein gene phaseolin. This sequence is capable of elevating gene expression in transgenic tobacco plants by as much as 150-fold when fused to a chimeric beta-glucuronidase reporter gene. Results presented in this paper demonstrate that nuclear extracts from carrot embryos bind to a phaseolin DNA sequence that includes a phaseolin activator sequence. This specific DNA binding activity is modulated during somatic embryogenesis. Two separable protein species react specifically with the labeled phaseolin DNA fragment (58.0 and 51.7 kDa). These results suggest that the cis- and trans-acting elements controlling gene expression have been highly conserved during evolution.

DNA↗
PubMed1989

Transmission and control of methicillin-resistant Staphylococcus aureus in a skilled nursing facility.

Methicillin-resistant Staphylococcus aureus (MRSA) is increasingly frequent in both acute care facilities (ACFs) and skilled nursing facilities (SNFs). Admissions to SNFs from ACFs with endemic MRSA are one likely source of infection in SNFs. The occurrence of MRSA in SNFs and the relative roles of ACFs and SNFs in MRSA transmission have not been well characterized. We conducted an epidemiologic investigation in an SNF reporting a high incidence of MRSA cases and found that the prevalence of MRSA exceeded that reported in acute care settings. Fifteen (9.1%) of the 164 residents were colonized or infected with MRSA. Risk factors for MRSA identified through a prevalence case-control study were nasogastric intubation (odds ratio = 5.5; 95% confidence interval = 1.2, 26.4), antibiotic therapy (OR = 3.9; CI = 1.2, 13.0), and hospitalization in an acute care facility within the previous six months (OR = 2.9; CI = 0.9, 9.7). During a three-month period, 6 of 100 new admissions were MRSA-positive; all positive patients were from ACFs. Five new cases also emerged from previously MRSA-negative residents. SNF residents are often discharged to ACFs. Transmission of MRSA within the SNF and the transfer of patients to ACFs increases the reservoir of potentially infective patients and the potential for MRSA infections in ACFs. Modest control measures, including targeted surveillance culturing and cohorting of colonized residents, may minimize MRSA transmission in the SNF and decrease the reservoir of MRSA in the community.

Aged↗
PubMed1989

The Wiltse pedicle screw fixation system. Early clinical results.

Ninety-nine patients were studied prospectively after spine fusion augmented with the Wiltse pedicle screw fixation system. Follow-up ranged from 12 to 34 months, averaging 20 months. There were 33 men and 66 women. Their ages ranged from 20 to 86, with the average age of 52. This was the first spine surgery in 23 patients. Seventy-six patients had had prior spine surgery. Spine fusion was attempted at one to four levels of the lumbosacral spine. Major perioperative complications were seen in seven patients (7%). Hardware failure was seen in seven cases (7%). Union was assessed by radiographs at 1 year or more after surgery in 82 patients (85%). In those 82 patients, union was seen in 56 (68%) and nonunion in 26 (32%). Change in lordosis was measured in 54 patients. The average change was a loss of 1.7 degrees lordosis per level fused. A questionnaire was answered by 79 patients (81%). Overall, 55 (70%) stated that they had some benefit from surgery, ten (13%) had no change, and 13 (17%) were worse.

Adult↗
PubMed1989

Interruption of Somatic Embryogenesis in Daucus carota L. by 5-Bromodeoxyuridine.

Embryogenic Daucus carota L. cells grown in 9 micromolar 2.4-dichlorophenoxyacetic acid are resistant to greater than 5 micromolar 5-bromodeoxyuridine (BrdU). In contrast, 5 micromolar BrdU strongly inhibits somatic embryogenesis within 24 hours after transfer of cells to an auxin-free medium. DNA synthesis rates in control and BrdU-treated cultures are rapid and similar; however, the DNA content does not reach levels as great in the presence of BrdU as in control cultures. BrdU substitutes for thymidine in the DNA in 28% of the available sites 48 hours after auxin removal. Following DNA repair, somatic embryogenesis resumes. BrdU DNA incorporation leads to somatic embryogenesis inhibition and provides an alternative to auxin treatment for the interruption of carrot cell culture differentiation.

Journal Article↗
PubMed1989

In situ arthrodesis without decompression for Grade-III or IV isthmic spondylolisthesis in adults who have severe sciatica.

Eight adults who had back pain and sciatica that was caused by Grade-III or IV isthmic spondylolisthesis of the fifth lumbar vertebra on the sacrum were treated consecutively by in situ arthrodesis without decompression. The anterior displacement of the fifth lumbar vertebra averaged 82 per cent (range, 66 to 118 per cent). The length of follow-up averaged 5.5 years (range, two to fourteen years). All of the arthrodeses resulted in a solid fusion and excellent relief of both the back pain and the sciatica. All of the preoperative neurological deficits resolved, with the exception of a decreased or absent Achilles-tendon reflex in two patients. There were no complications, and all of the patients returned to their preoperative occupations.

Adult↗
PubMed1988

The nucleolar RNA-binding protein B-36 is highly conserved among plants.

The nucleolar protein B-36 is an RNA-associated protein which has a number of properties in common with pre-mRNA-binding proteins (hnRNP proteins). Like the hnRNP proteins, B-36 appears to be evolutionarily conserved among various eukaryotes (protists and several animal species). The conservation of B-36 throughout the plant kingdom has been investigated using a panel of nine monoclonal antibodies previously shown to recognize a minimum of four different epitopes in Physarum B-36, the protein used to generate the monoclonal antibodies. Two of the epitopes (I and III) are widely conserved in 34 kDa proteins (presumably B-36 homologues) from the various species tested (Chlamydomonas, moss, fern, oat, onion, carrot, and bean). Using immunofluorescence localization in moss and carrot protoplasts, the cross-reacting proteins were shown to be restricted to the nucleolus, further confirming their probable homology to B-36. Epitopes I and III are also unique to the B-36 homologues as demonstrated by the failure of any other bands to cross-react. Another epitope (IV) was specifically recognized in the plant B-36 homologues but exhibited greatly reduced affinity for the monoclonal antibody relative to Physarum B-36. The remaining epitope (II), unlike the others, exhibited variable conservation in the plant B-36 homologues and, in addition, was present in several other seemingly unrelated proteins. Finally, several of the plant species exhibited two cross-reacting variants at roughly the 34 kDa position and in at least one of these cases a single monoclonal antibody was able to distinguish between the two variants, a result indicating that the variants do have bona fide structural differences.(ABSTRACT TRUNCATED AT 250 WORDS)

Carrier Proteins↗
PubMed1987

Analysis of the morphometric characteristics of the thoracic and lumbar pedicles.

A total of 2,905 pedicle measurements were made from T1-L5. Measurements were made from spinal computerized tomography (CT) scan examinations and individual vertebral specimen roentgenograms. Parameters considered were the pedicle isthmus width in the transverse and sagittal planes, pedicle angles in the transverse and sagittal planes, and the depth to the anterior cortex in a line parallel to the midline of the vertebral body and along the pedicle axis. There was no significant difference between data obtained from CT scans and specimen roentgenograms. Pedicles were widest at L5 and narrowest at T5 in the transverse plane. The widest pedicles in the sagittal plane were seen at T11, the narrowest at T1. Due to the oval shape of the pedicle, the sagittal plane width was generally larger than the transverse plane width. The largest pedicle angle in the transverse plane was at L5. The posterolateral to anterolateral pedicle axis orientation in the transverse plane, seen at other levels throughout the thoracolumbar spine, reversed at T12. In the sagittal plane, the pedicles angled caudally at L5 and cephaladly from L3-T1. The depth to the anterior cortex was significantly longer along the pedicle axis than along a line parallel to the midline of the vertebral body at all levels with the exception of T12 and T11.

Adult↗
PubMed1987

The effects of nitrogen deficiency on pigments and lipids of cyanobacteria.

In contrast to what happens in higher plants and eukaryotic algae, a nitrogen deficiency during growth causes a change in pigment composition but no significant changes in whole cell lipid and fatty acid composition of the two Cyanobacteria, Pseudanabaena sp. (strain M2) and Oscillatoria splendida (strain L3). Nitrogen deficiency does not affect the cellular content in chlorophyll a, but it causes a selective loss in phycobiliproteins; carotenoid content increases with phycocyanin depletion. The major cellular lipids in both Cyanobacteria studied are monogalactosyl diacylglycerol, digalactosyl diacylglycerol, sulfoquinovosyl diacylglycerol, and phosphatidylglycerol. The fatty acid composition is particularly interesting as both these filamentous Oscillatoriaceae show important contents in alpha- and gamma-linolenic (18:3) and parinaric (18:4) acids. This seems to be very unusual in Cyanobacteria.

Journal Article↗
PubMed1986

Cytokinin activity induced by thidiazuron.

The diphenylurea derivative thidiazuron induces a variety of cytokinin responses. Levels above 5 x 10(-9) molar and 4 x 10(-7) molar stimulate maximum soybean callus growth and radish cotyledon expansion, respectively. A wider range of dose response related effects follows thidiazuron induced tobacco plant regeneration. Analysis of soybean callus extracts strongly suggests that thidiazuron treatment creates an accumulation and/or synthesis of purine cytokinins, able to induce the growth, expansion and regeneration, mentioned above.

Journal Article↗
PubMed1986

Treatment of septic olecranon and prepatellar bursitis with percutaneous placement of a suction-irrigation system. A report of 12 cases.

Ten cases of septic olecranon bursitis and two cases of septic prepatellar bursitis were treated in the period from 1975 to 1980 with antibiotics and percutaneous tube placement for suction-drainage and local antibiotic irrigation. All patients had positive bacterial cultures: Staphylococcus aureus in nine, beta-hemolytic Streptococcus in two, and Staphylococcus epidermidis in one. Intravenous antibiotics, local suction-drainage, and irrigation with a solution of 1% kanamycin and 0.1% polymyxin controlled the infection in each case. The antibiotic treatment averaged 19 days, compared with 24 days in a series in which suction-irrigation was not used. In contrast with studies in which aspiration or incision and drainage were performed, there were no complications or recurrences. Percutaneous suction-irrigation appears to be a safe, effective method of treatment that is particularly beneficial in severe cases of septic bursitis in which continuous drainage is desirable.

Adult↗
PubMed1986

Chemonucleolysis. A ten-year retrospective study.

An 11.8-year median follow-up evaluation of 42 "ideal" patients who had chemonucleolysis was obtained by examination, questionnaire, and roentgenograms. The excellent and good rating of this group was 81%, as compared to the total of 135 patients previously evaluated at 42 months and showing 85.2%. No complications were noted. Disc space rewidening, after initial narrowing, was observed in eight patients and 26% of all discs injected. While all who showed rewidening had excellent results, widening was not necessary to achieve an excellent rating. Marked narrowing and sclerosis of intervertebral margins were seen in many excellent and good clinical results. Chemonucleolysis represents a viable option as definitive treatment for a herniated nucleus pulposus in carefully selected patients.

Chymopapain↗
PubMed1986

Plain roentgenograms of the spine in the injured athlete.

The valued techniques and types of plain roentgenograms of the cervical spine and the lumbar spine in athletic injuries are discussed. A considerable number of injury types exist, as well as a large number of various roentgenographic views that the physician may order. In approaching the athlete with an injured spine, the physician depends on the length of symptoms, associated physical findings such as neurologic deficit, and clinical information available for both the cervical and lumbar spine injury.

Athletic Injuries↗
PubMed1986

A biomechanical study of intrapeduncular screw fixation in the lumbosacral spine.

This laboratory experiment was undertaken to identify factors contributing to intrapeduncular screw fixation in the vertebra. Testing was performed in axial pull-out and cyclic loading modes using multiple screw designs inserted to various depths into fresh human lumbosacral vertebra. The degree of osteoporosis played a major role in pull-out strength. Larger diameter, full-threaded screws inserted deep enough to engage the anterior vertebral cortex resulted in the most secure fixation. In the sacrum, the second sacral pedicle was the weakest location of insertion. Screws aimed laterally into the ala at 45 degrees or medially into the first sacral pedicle resisted larger axial pull-out loads than those inserted straight anteriorly into the ala. Methyl methacrylate was found to restore secure fixation in previously-loosened screws and pressurization of cement doubled the pull-out force. In cyclic load tests, deeper-inserted screws were found to withstand a greater number of cycles before loosening. Measurements of pedicle outer cortical diameters were found in many specimens to be smaller than both the 4.5-mm and 6.5-mm diameter screws.

Aged↗
PubMed1985

Mutagenicity of three agricultural soils.

A chemical and biological testing protocol was employed to evaluate the mutagenic potential of the organic compounds extracted from three agricultural soils. The analytical procedures used included bioassays with Salmonella typhimurium and Aspergillus nidulans for the detection of point mutations and a gas chromatography/mass spectrometry/computer system to identify major organic constituents. The extracts of all three soils exhibited mutagenic response in the bioassays. At a dose level of 1000 micrograms per plate, the organic extract of the Bastrop clay induced 434 net revertants; while at the same dose level the Norwood sandy clay and the Sassafrass sandy loam induced 35 and 178 net revertants, respectively, in the Salmonella assay with metabolic activation. In the Aspergillus assay, the extract of the Norwood and Bastrop soils induced a positive response without metabolic activation; this effect was reduced or eliminated in the presence of metabolic activation. Chemical analysis identified a variety of initiators, promotors, inhibitors, and cocarcinogens; however, there were no mutagenic compounds identified in any of the soil extracts. The results of this combined testing protocol indicate that the agricultural soils tested had an inherent level of mutagenic activity, which was not detected by GC/MS analysis alone, and this activity may be related to the past history of agricultural practices, including biocide applications, fertilization, and cultivation.

Animals↗