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Biomedical subjects

N Harris

Publications and source records attributed to N Harris.

At least 145 records · Page 8Linked to original sources
PubMed1985

An outbreak of Yersinia enterocolitica infections caused by contaminated tofu (soybean curd).

The authors investigated 50 Yersinia enterocolitica infections during an outbreak of illness due to contaminated tofu (soybean curd) in Washington State between December 15, 1981 and February 22, 1982. The most common clinical syndrome (36 patients) was gastrointestinal infection for which two patients underwent appendectomies and one a partial colectomy. Of the remaining 14 patients, six had extraintestinal infections, two had fever alone, and six were asymptomatic. The patients with enteric infections were younger (median age three years) than those with extraintestinal infections (median age 28 years). In a case-control study of enteritis patients, illness was associated with ingestion of one brand of tofu (p less than 0.01). Ninety-two per cent of patients with gastrointestinal infections and 33% with extraintestinal infections recalled having eaten the implicated product. Y. enterocolitica serotype O:8, the most common serotype isolated from patients, was also isolated from tofu and the plant's untreated spring water. There was little clinical or laboratory evidence of secondary spread to family members who did not eat tofu. The outbreak demonstrates the transmission of Y. enterocolitica from nature to man and the potential of "natural" foods as vehicles for environmental pathogens.

Adolescent↗
PubMed1985

Isolation of a full-length mouse cDNA clone coding for an immunologically distinct p53 molecule.

Transfection of a cloned p53 gene into a p53 nonproducer Abelson murine leukemia virus-transformed cell line, L12, reconstituted p53 expression. The protein expressed in these cells was indistinguishable from that naturally expressed in p53 producer tumor cells. Conversely, p53 protein expressed in L12-derived clones that were established by transfection with a full-length p53 cDNA clone (pM8) exhibited a discrete immunological form. Immunoprecipitation of p53 with a panel of monoclonal anti-p53 antibodies showed that L12-derived clones that were transfected with the genomic p53 clone contained the same antigenic determinants as those found in the p53 protein expressed in tumor cells. These p53 proteins bound all monoclonal antibody types as well as the polyclonal anti-p53 tested. However, L12-derived clones established by transfection of the p53 cDNA clone (pM8) expressed a p53 protein that bound the RA3-2C2 and PAb200.47 anti-p53 monoclonal antibodies as well as polyclonal anti-p53 serum but totally lacked the antigenic receptor for the PAb122 and PAb421 monoclonal antibodies. The p53 proteins expressed by either genomic or cDNA p53 clones exhibited the same apparent molecular sizes and identical partial peptide maps. We suggest that transfection of the p53 gene induced expression of the entire group of the possible mRNA species, whereas cloned p53 cDNA (pM8) represented a single mRNA molecule that codes for a discrete species of p53 protein.

Animals↗
PubMed1984

Reconstitution of p53 expression in a nonproducer Ab-MuLV-transformed cell line by transfection of a functional p53 gene.

L12 are Ab-MuLV-transformed cells that express the abl p120 oncogene product but lack the cellularly encoded p53. The functional p53 gene in these cells has been inactivated by the insertion of Moloney virus-like sequences into the first p53 intron. Transfection of L12 cells with a functional p53 gene, contained in a 16 kb Eco RI genomic cloned fragment gave rise to L12-derived cell lines with novel p53 sequences of various sizes and copy number. A high percentage of L12-derived clones efficiently transcribed p53 mRNA and synthesized the p53 protein. Whereas injection of L12 parental cells into syngeneic mice caused the development of local tumors that later regressed, L12-derived clones that expressed p53 caused lethal tumors in syngeneic mice, thus behaving similarly to other Ab-MuLV-transformed p53-producer cell lines. These results suggest that the expression of p53 is essential for tumor cells to exhibit a fully transformed phenotype, manifested in lethal tumors in syngeneic mice.

Abelson murine leukemia virus↗
PubMed1982

Influences of hypothermia, cold, and isolation stress on the severity of coronary artery ligation-induced arrhythmias in rats.

With a view to increasing the severity of the arrhythmias that arise following coronary artery ligation in anesthetized rats, the influences of exposure to lowered environmental temperature (LET) (21 to 13 degrees C) and isolation stress were examined. Housing rats singly for 48 hr, prior to the induction of arrhythmias, caused the most marked changes in the severity of the model; the incidence of ventricular fibrillation and mortality were increase from 43 to 90% and 9 to 60%, respectively. Exposure of multiply housed rats to LET for 48 hr also significantly increased mortality from fibrillation. A combination of LET plus isolation stress, however, did not further increase the severity of the arrhythmias following ligation. Acute hypothermia (body temperature reduced to 30 or 25 degrees C) did not significantly enhance the severity of the model.

Animals↗
PubMed1982

Lymphoma with autoimmune neutropenia and hepatic sinusoidal infiltration: a syndrome.

A relation between lymphoma and autoimmune neutropenia, unlike autoimmune hemolytic anemia and idiopathic thrombocytopenic purpura, has not previously been well documented. We report a patient with a disorder presenting as autoimmune agranulocytosis, splenomegaly, and infiltration of the hepatic sinusoids by lymphocytes. Antineutrophil antibodies were present. Over a 2 1/2-year period, the illness progressed to an aggressive, poorly differentiated lymphocytic lymphoma with terminal liver failure and fibrosis. Peripheral blood lymphocyte markers identified the tumor as a proliferation of T-cells of the helper class. A review of previous literature disclosed other reports of similar patients who had neutropenia, a lymphoproliferative illness, and hepatic disease. Our case is representative of a previously unrecognized syndrome characterized by autoimmune neutropenia in the setting of a lymphoproliferative disorder of T cells, with a predilection for liver involvement.

Agranulocytosis↗
PubMed1979

Alimentary tract complications after renal transplantation.

A computer analysis of post renal transplantation gastrointestinal problems was performed to identify important associated clinical factors. Thirty-seven per cent of all transplant recipients developed one or more significant problems. Hemorrhage, nondiverticular intestinal perforation, and esophagitis occurred most frequently in hospitalized patients. Pancreatitis, diverticulitis, and gastroduodenal perforation occurred characteristically in long-term survivors with well functioning allografts. Eleven of 32 HLA identical recipients treated with maintenance corticosteroids during stable kidney function developed gastrointestinal disease while only one of 13 HLA identical recipients not given maintenance steroids developed a problem, which strongly suggests a causal role for steroids in the development of late complications. The association of preexisting peptic ulcer and diverticular disease with hemorrhage and perforation supports previous recommendations that documented peptic ulcer disease or diverticulitis should be corrected surgically prior to transplantation.

Adolescent↗
PubMed1979

Murine leukemia virus-associated cell surface antigens in rats neonatally infected with Gross murine leukemia virus.

The inoculation of newborn W/F, Lew, AS and DA rats with Gross murine leukemia virus (G-MuLV) resulted in the prompt appearance of cells with viral protein antigens (VPA) on their surfaces. These were first found in the bone marrow and spleen and later in the thymus gland. As the animals developed, the VPA-positive population expanded and the intensity of the fluorescence increased. In the spleen, the cells with the strongest fluorescence had the properties of T-cells, but in both spleen and bone marrow low levels of VPA were found on non-T-cells. The VPA-positive population expanded long before malignant cells could be detected and, in most animals, the entire T-cell compartment became antigen-positive. These animals were unable to respond to G-MuLV antigens and many eventually developed leukemia. However, some animals apparently broke the tolerance that followed neonatal infection and eliminated VPA-positive cells from their tissues

AKR murine leukemia virus↗
PubMed1978

A method for calculating acetabular anteversion in children.

A method of calculating the degree of anteversion of the acetabular fossa is described. A posterior-anterior projection of the prone pelvis with a long focus film and focus object distance is used. The distance between the anterior and posterior rims of the fossa as projected on the films is measured and then divided by a distance equivalent to the diameter: this yields the sin of the anteversion angle. The angle is rapidly calculated with a pocket calculator.

Acetabulum↗
PubMed1978

Isolated mesenteric desmoids (mesenteric fibromatosis).

The so-called desmoid tumour is an important member of a group of conditions termed "the fibromatoses" which are characterised by an infiltrating fibroblastic proliferation without features of an inflammatory response. While desmoids most frequently arise in the anterior abdominal wall, they may also be extra-abdominal or intra-abdominal in location. Mesenteric desmoids are relatively rare. They may occur in association with Gardner's syndrome, especially following colectomy, or as an isolated abnormality in otherwise normal patients. In the present paper the authors describe the clinical, radiological and pathological findings in two patients with isolated mesenteric desmoids. The radiological differential diagnosis is also briefly discussed.

Adult↗
PubMed1977

The effect of thymosin on patients with disseminated malignancies. A phase I study.

A Phase I clinical trial of thymosin administered in doses of 10 to 250 mg/M2 intramuscularly for seven days was undertaken in ten patients with disseminated malignancies and evidence of immunoincompetence. Toxicity was minimal; one patient experienced a mild urticarial rash which cleared spontaneously, two patients developed low grade fever and one patient experienced pain at the injection site. There was no evidence of systemic toxicity or parenchymal organ dysfunction. Thymosin administration was associated with an increase in the E-rosette forming capacity of the patient's lymphocytes and the development of new skin test reactivity to recall antigens in some of these patients. One objective tumor response was noted. These findings are preliminary but are encouraging for further utilization of thymosin as an immunostimulant in cancer patients with immunoincompetence.

Adenocarcinoma↗
PubMed1976

Regulation of reserve protein metabolism in the cotyledons of mung bean seedlings.

Seedling growth in mung beans (Phaseolus aureus, Roxb.) is accompanied by the metabolism of the reserve proteins, and the appearance in the cotyledons of a proteolytic enzyme with endopeptidase activity. Enzyme activity increases 25-fold during the first 5 days of growth. Cotyledon extracts prepared from seeds imbibed for 24 hr with water do not react with rabbit endopeptidase antiserum, which suggests that the enzyme is not present in the seeds as a zymogen. Labeling experiments show that the enzyme is synthesized in the course of seedling growth. The endopeptidase is localized in the protein bodies, and the specific activity of the enzyme in these organelles increases 30-fold. Ultrastructural studies show that the rough endoplasmic reticulum proliferates and may give rise to vesicles which fuse with the protein bodies prior to reserve protein digestion. These vesicles could be the primary lysosomes which transport the enzyme from its site of synthesis to its site of action.

Journal Article↗
PubMed1975

Histochemical and biochemical observations on storage protein metabolism and protein body autolysis in cotyledons of germinating mung beans.

Storage protein hydrolysis in the cotyledons of germinating mung beans (Phaseolus aureus Roxb.) was examined by histochemical techniques, and the autolytic capacity of isolated protein bodies was studied with biochemical methods. The localization of endopeptidase activity within the cotyledons was studied using an India ink-gelatin film technique. After 24 hours of imbibition, a low level of endopeptidase activity was found throughout the storage tissues of the cotyledons. A marked increase in activity was noted in cells farthest from the vascular bundles 48 to 60 hours after the start of imbibition. The decrease in storage protein followed the same spatial distribution starting in the cells farthest from the bundles. The cotyledons contain a population of cells in various stages of endopeptidase activity enhancement and storage protein degradation. A wave of endopeptidase activity moves progressively through the cotyledons towards the vascular bundles leaving behind areas devoid of stored reserves and low in endopeptidase activity. Observations on the morphology of protein bodies during germination indicate that the membrane surrounding them remains intact, while the reserves disappear. This result suggests that the protein bodies may be undergoing autolysis. To determine whether this may indeed be the case, protein bodies were isolated from the meal of mung bean seeds using an aqueous medium containing 80% glycerol. The protein body preparations and the cytoplasm were assayed for the presence of a number of enzymes which may be involved in the breakdown of the storage proteins. The protein bodies contained all, or nearly all, of the carboxypeptidase, alpha-mannosidase, N-acetyl-beta-glucosaminidase, and caseolytic activity. The cytoplasm contained all, or most, of the leucine aminopeptidase and the trypsin-like activity (benzoyl arginine-p-nitroanalide as substrate). Incubation of the isolated protein bodies resulted in the release of amino acids. An analysis of the products of hydrolysis indicated that very little, if any, storage protein was being hydrolyzed during the incubation. Hydrolysis of the storage proteins present in the protein bodies was greatly accelerated by the addition of extracts from the cotyledons of 4-day-old seedlings. The results suggest that new enzymic activities not present in the protein bodies isolated from dry seeds must either be activated or synthesized and possibly added to the protein bodies before storage protein breakdown can begin.

Journal Article↗