Search PubMed⌕ Search

Biomedical subjects

J D Jones

Publications and source records attributed to J D Jones.

At least 163 records · Page 9Linked to original sources
PubMed1985

Use and limitations of serum total and lipid-bound sialic acid concentrations as markers for colorectal cancer.

Concentrations of total serum N-acetyl-neuraminic acid (NANA) by high-performance liquid chromatography (HPLC) and lipid-bound sialic acid (LSA) by resorcinol procedure were evaluated and compared to carcinoembryonic antigen (CEA) as markers for colorectal carcinoma. Elevated concentrations of NANA were found in 32% of patients with nonmalignant disorders, 28% of patients with localized cancer, and 87% of patients with metastatic cancer. All three markers correlated with the extent of metastasis of colorectal carcinoma. Strong correlation was found between NANA and LSA measurements, whereas measurement of the sialic acid markers provide information that can not be derived from the measurement of CEA. NANA and LSA show promise as supplemental markers for staging and monitoring colorectal cancer, but they are neither sensitive nor specific enough for cancer screening.

Adult↗
PubMed1985

High level expression of introduced chimaeric genes in regenerated transformed plants.

Promoter DNA sequences from a petunia chlorophyll a/b binding protein gene were fused to octopine synthase DNA sequences and the resulting chimaeric genes were introduced into petunia and tobacco cells. Populations of transformed regenerated petunia plants containing the chimaeric genes were examined so that the expression of any particular construction could be compared between independent transformants. Substantial variation was observed between transformants in the level of chimaeric gene expression. In general, transcriptional fusions in which a linker sequence interrupted the 5'-untranslated region gave rise to less chimaeric mRNA accumulation than a translational fusion. In the most actively expressing transformants the amount of mRNA from the introduced chimaeric genes was half that of the endogenous wild-type gene. Transcription initiated at the same place in the chimaeric and endogenous genes. Construction of the translational cab/ocs fusion caused three amino acid changes in the octopine synthase protein and functional octopine synthase enzyme was absent from plants in which mRNA for the chimaeric gene was abundantly expressed.

Amino Acid Oxidoreductases↗
PubMed1985

Diagnostic and prognostic implications of plasma amino acid determinations in chronic active hepatitis.

To further assess the molar ratio of branched-chain to aromatic amino acids as a measure of disease activity, we correlated results of this test with histologic features of inflammation, standard biochemical tests, and prognosis in 68 patients with severe chronic active hepatitis. An abnormal molar ratio (less than 3.0) reflected histologic findings of chronic active hepatitis in 26 of 35 instances. A normal molar ratio (greater than or equal to 3.0), however, was associated with histologic features of chronic active hepatitis in nine of 14 instances. Molar ratio abnormalities occurred more frequently in patients with cirrhosis than without cirrhosis (95% vs 45%, P less than 0.01). Only one of 20 patients with cirrhosis had a normal ratio, and none of 12 followed serially during therapy improved the ratio to normal. No correlation was seen between the molar ratio and severity of inflammation or serum levels of aspartate aminotransferase, albumin, bilirubin, and gamma globulin. When corticosteroids were discontinued, relapse occurred as frequently in patients with a normal molar ratio as in others (80% vs 71%), and the presence of an abnormal ratio did not preclude a sustained remission after treatment. We conclude that the plasma molar ratio does not reflect histologic activity, correlate with standard liver function tests, or indicate disease behavior after treatment withdrawal. A normal molar ratio during or after treatment, however, may exclude cirrhosis.

Adolescent↗
PubMed1985

Panoramic radiographic examination of edentulous patients.

A study of panoramic radiographs made on 114 edentulous patients was described. Six radiographic entities were identified: root fragments, retained teeth, radiolucencies, radiopacities, foreign bodies, and mental foramina at or near the crest of the residual ridge. The percent of positive findings in this study and those of previous studies support the fact that one of three edentulous patients has a potentially complicating condition within the denture base foundation. These investigations stress the necessity of radiographic examination of all edentulous patients prior to treatment with complete dentures. The high incidence of positive findings suggests not only the need for radiographic examinations of all patients, but also the frequency with which the dentist is faced with the necessity of modifying the treatment plan.

Foreign Bodies↗
PubMed1984

Role of the dental hygienist in the prosthodontic practice.

Prosthodontic practices can benefit from the inclusion of a dental hygienist on the dental team. The dental hygienist can successfully complete procedures traditionally performed by the dentist. Delegation of these duties permits the dentist to spend time and energy on intricate procedures for which he or she has special expertise. The major modalities of responsibility that can be delegated include diagnostic data collection, educational and preventive services, and corrective therapy. It has been suggested that there is a need for expanding the duties of auxiliaries for prosthodontics in the future. It is our recommendation to use effectively the important auxiliary, the dental hygienist, in prosthodontic practice. For prosthodontic patients, the importance of the dental hygienist can be supported from two perspectives. First, the dental hygienist is formally educated in the oral and basic sciences and is qualified to perform intraoral procedures. Second, the dental hygienist is able to educate patients in regard to diet and oral hygiene habits. The dental hygienist's role in the prosthodontic practice has a potential that must not be overlooked. This opportunity, when provided, can be challenging, successful, and beneficial to the dentist, the patient, and the practice of prosthodontics.

Dental Hygienists↗
PubMed1984

D-Lactic acidosis and encephalopathy after jejunoileostomy: response to overfeeding and to fasting in humans.

Two patients with recurring attacks of encephalopathy after jejunoileostomy for morbid obesity had elevated D-lactate concentrations in blood and urine. The syndrome and the biochemical abnormalities were reproduced by ingestion of a high carbohydrate diet. In the second case, fasting and intravenous supplementation with amino acids and glucose resulted in the disappearance of D-lactate from the urine and blood and amelioration of the symptoms. Stool cultures from the second patient were shown to be capable of producing D-lactate, and concentrations of D-lactate in saline and peptone yeast broth filtrates of the stool paralleled the changes in urinary excretion of the D-lactate during fasting and overfeeding. Thus, we have demonstrated a temporal relationship between the neurologic symptoms and the elevated concentrations of D-lactate in blood, urine, and stool. Whether D-lactate accounts for part or all of the encephalopathic changes remains to be determined.

Acidosis↗
PubMed1984

Rhizobium meliloti nodulation genes allow Agrobacterium tumefaciens and Escherichia coli to form pseudonodules on alfalfa.

Regions of the Rhizobium meliloti symbiotic plasmid (20 to 40 kilobase pairs long) containing nodulation (nod) genes were transferred to Agrobacterium tumefaciens or Escherichia coli by conjugation. The A. tumefaciens and E. coli transconjugants elicited root hair curling and the formation of ineffective pseudonodules on inoculated alfalfa plants. A tumefaciens elicited pseudonodules formed at a variable frequency, ranging from 15 to 45%, irrespective of the presence of the Ti plasmid. These pseudonodules developed characteristic nodule meristems, and in some nodules, infection threads were found within the interior of nodules. Infrequently, infection threads penetrated deformed root hairs, but these threads were found only in a minority of nodules. There was no evidence of bacterial release from the infection threads. In addition to being found within threads, agrobacteria were also found in intercellular spaces and within nodule cells that had senesced . In the latter case, the bacteria appeared to invade the nodule cells independently of infection threads and degenerated at the same time as the senescing host cells. No peribacteroid membranes enclosed any agrobacteria , and no bacteroid differentiation was observed. In contrast to the A. tumefaciens-induced pseudonodules , the E. coli-induced pseudonodules were completely devoid of bacteria; infection threads were not found to penetrate root hairs or within nodules. Our results suggest that relatively few Rhizobium genes are involved in the earliest stages of nodulation, and that curling of root hairs and penetration of bacteria via root hair infection threads are not prerequisites for nodule meristem formation in alfalfa.

Base Sequence↗
PubMed1984

Acardia: case report.

Explore the source record for details and available documents.

Abnormalities, Severe Teratoid↗
PubMed1983

Klebsiella pneumoniae nifA product activates the Rhizobium meliloti nitrogenase promoter.

Bacteria in the genus Rhizobium normally fix nitrogen only when they interact with leguminous plants to produce on the roots a highly differentiated structure, the nodule, within which the bacteria differentiate into nitrogen-fixing bacteroids. By contrast, the enteric bacterium Klebsiella pneumoniae reduces nitrogen in a free-living state in conditions of low oxygen tension and deficiency of fixed nitrogen. In K. pneumoniae, the overall circuitry by which nitrogen-fixation (nif) genes are regulated has been elucidated. In response to ammonia starvation, the product of the glnG gene activates transcription of the nifLA operon; this activation is dependent on the product of glnF (ref. 4). The nifA gene product is in turn required for transcription of all the other nif genes, including the nifHDK operon which codes for the subunits of nitrogenase. In contrast, very little is known about the sequence of events involved in the regulated change in rhizobial nif gene expression associated with bacteroid differentiation. In the work described here, we identify the K. pneumoniae and Rhizobium meliloti nifHDK promoters by mapping the in vivo start points of transcription. By defining and comparing the DNA sequences of these two promoters, we find that they share an unexpected degree of homology. Further, by constructing fusions of each of the two promoters to the lacZ gene from Escherichia coli, we show that both promoters are activated by the product of the K. pneumoniae nifA gene.

Base Sequence↗