Biomedical subjects

M L Jackson

Publications and source records attributed to M L Jackson.

At least 37 records · Page 2Linked to original sources

PubMed1997

The importance of healthy communities of higher education.

A framework for understanding issues that contribute to vibrant and healthy communities of higher education is presented. The focus is on how individual and community health relate to institutional missions, purposes, and goals. This framework may be applied to 2-year and 4-year colleges and universities whether they are public, private, research, teaching, sectarian, religious, residential, or computer institutions. The following questions are addressed: Why should colleges maintain healthy communities? How do we define health in colleges and universities? Why is this important for society? What are the key responsibilities in fostering healthy educational communities? Who is responsible for assuring that this happens? What added value do personal and community health yield for institutions of higher education? Readers are provided with a rationale for assessing the role and importance of individual and community health in their campus environments; engaging students, faculty, and staff in discussions about these issues; and determining whether more thorough, systematic, and intensive community health assessments or interventions are needed in their campus settings.

Health↗

PubMed1996

Use of immunohistochemistry and polymerase chain reaction for detection of oncornaviruses in formalin-fixed, paraffin-embedded fibrosarcomas from cats.

OBJECTIVE: To determine whether there was intralesional infection or expression of FeLV or feline sarcoma virus in suspected vaccine-associated fibrosarcomas in cats. DESIGN: Prospective case series. SAMPLE POPULATION: 130 suspected vaccine-associated fibrosarcomas from cats and 1 multicentric fibrosarcoma from 1 cat. PROCEDURE: Excisional biopsy specimens were fixed in formalin and embedded in paraffin. Expression of FeLV antigen was assessed, using a polyclonal goat anti-FeLV glycoprotein 70 (gp 70) serum and an avidinbiotin immunoperoxidase staining technique. The FeLV genome was detected with a polymerase chain reaction (PCR), using primers targeted to a conserved sequence in the untranslated region of the long terminal repeat (LTR) of the FeLV. RESULTS: FeLV gp 70 and LTR sequence were detected in a multicentric fibrosarcoma. All 130 of the suspected vaccine-associated fibrosarcomas were FeLV gp 70 negative on the basis of immunohistochemical test results: 100 fibrosarcomas also were examined by use of PCR and were negative for FeLV LTR region. CLINICAL IMPLICATIONS: Exogenous retroviruses, FeLV, and feline sarcoma virus were not detected in these suspected vaccine-associated fibrosarcomas, using immunohistochemistry and PCR. Additional testing will be required to determine the nature of genomic alterations that are involved in the oncogenesis of vaccine-associated fibrosarcomas in cats.

Animals↗

PubMed1996

Sequence analysis of the putative viral enhancer in tissues from 33 cats with various feline leukemia virus-related diseases.

Diseases resulting from infection by feline leukemia virus (FeLV) and several other retroviruses relate in part, to non-coding regulatory sequences within the viral long terminal repeat (LTR). Both enhancer repeats and mutations within the LTR have been implicated in FeLV related disease. In order to investigate the relationship between nucleotide sequence of the FeLV LTR and disease, tissues from 33 cats with different types of degenerative and proliferative FeLV-related disease were studied. An FeLV LTR region containing the putative transcriptional enhancer unit was amplified by polymerase chain reaction (PCR) from FeLV-infected tissues. Phylogenetic analysis of FeLV 3'unique (U3) sequences revealed only one meaningful grouping which contained 4 of the 5 antigen-negative lymphosarcomas (LSAs). No sequence duplications were found in any of the 33 FeLV U3 regions. Point mutations relative to the corresponding region of FeLV-A/Glasgow, were identified at 102 positions; 68 of these were accounted for by mutations at 5 locations. Only 1 point mutation was found within the leukemia virus b-simian virus 40-like core (LVb-CORE) site. However, the nuclear factor 1 (NF1) site contained 11 mutations, and the FeLV-specific (FLV-1) site contained 26 mutations. Most of the remaining mutations were upstream of the LVB site between glucocorticoid response element (GRE) and FLV-1. The 10 LSAs, particularly the 5 antigen-negative LSAs, deviated least from the corresponding sequence for FeLV-A/Glasgow. Conclusions were that the spectrum of neoplastic and non-neoplastic FeLV-related diseases investigated in this study, developed in the presence of FeLVs containing the single enhancer unit. The significance of the point mutations is unknown, however, those occurring with high frequency and within nuclear protein binding should be first to be investigated in functional studies.

Animals↗

PubMed1996

Feline leukemia virus detection by ELISA and PCR in peripheral blood from 68 cats with high, moderate, or low suspicion of having FeLV-related disease.

Clinicopathologic criteria were used to group 68 cats according to high, moderate, or low suspicion of having feline leukemia virus (FeLV)-related disease. Peripheral blood samples were tested for FeLV antigen by enzyme-linked immunosorbent assay (ELISA) and for FeLV DNA by polymerase chain reaction (PCR). There was no significant difference between ELISA and PCR results in the 68 cats. In the high-suspicion group, 46%(11/24) of cytopenic cats were test positive (ELISA and PCR) and 87% (13/15) with hemopoietic neoplasms were test-positive. Also within the high suspicion group, test-positive cats were 2.5 times more likely to die within the 1 year follow-up period than were test-negative (ELISA and PCR) cats. Among cats in the moderate-suspicion group, 15% (2/13) were test-positive, and none (0/16) of the cats in the low suspicion group was test positive. The relative risk of a positive test (ELISA and PCR) in the high suspicion group was 3.7 times that for the moderate-suspicion group and 22.8 times that for the low suspicion group. There was no significant difference in the relative risk of a positive test result between the moderate and low suspicion groups. The results indicate that FeLV detection by PCR can be adapted for diagnostic purposes using peripheral blood samples, however, results do not differ significantly from FeLV ELISA results. Also, a proportion of cats with a high suspicion of having FeLV-related cytopenia and hemopoietic tumors are negative for both circulating FeLV antigen and DNA. These cats may not have FeLV-related disease, or FeLV may exist in a disease-producing but nonreplicating form ultimately detectable by PCR in tissues other than peripheral blood.

Animals↗

PubMed1996

Development of a scale to measure discomfort during pregnancy.

During pregnancy fundamental changes occur in a woman's body that make physical discomforts almost unavoidable. Extensive literature searches revealed that there was no psychometrically acceptable tool available to assess accurately maternal physical discomfort. This paper presents the procedures undertaken to develop the Maternal Physical Discomfort Scale (MPDS), an assessment instrument designed to quantify the type and number of maternal physical discomforts. The MPDS, a scale consisting of 36 items, was developed and psychometrically evaluated using factor analysis, item response theory and reliability measures. The initial version of the scale was validated by a sample of 307 pregnant women. Based on the result from this sample, the MPDS was modified to 33 items and validated by a further sample of 125 pregnant women. The MPDS developed in this study was demonstrated to have content and construct validity and to be reliable.

Factor Analysis, Statistical↗

PubMed1996

Immunohistochemical identification of B and T lymphocytes in formalin-fixed, paraffin-embedded feline lymphosarcomas: relation to feline leukemia virus status, tumor site, and patient age.

The lymphocyte phenotype of 70 formalin-fixed, paraffin-embedded feline lymphosarcomas (LSAs) was determined immunohistochemically using a T cell polyclonal antibody, and a B cell monoclonal antibody. Forty-seven of 70 (67%) tumors were T cell, 19/70 (27%) were B cell, and 4/70 (6%) did not stain with either marker. Thirty-eight of 70 (54%) tumors were positive for feline leukemia virus (FeLV) antigen by immunohistochemistry (IHC), and 52/70 (74%) tumors were positive for FeLV DNA using the polymerase chain reaction (PCR). B cell tumors were as frequently FeLV-positive as T cell tumors using either IHC or PCR. Intestinal tumors were more likely to be B cell than T. The incidence of B and T cell tumors was not different among young (< or = 3 y), middle-aged (> 3 y to < or = 8 y), and old (> 8 y) cats. Both B and T cell tumors from old cats were FeLV-positive more often by PCR than by IHC. Feline leukemia virus DNA but not antigen, was detected in B cell tumors and intestinal tumors from cats > 8 y as often as it was detected in B cell tumors and intestinal tumors from cats < or = 8 y. Previously, most B cell and intestinal tumors from old cats were considered to be negative for FeLV. Here, the results suggest involvement of latent or replication-defective forms of the virus in such tumors from old cats. This study supports a role for FeLV in feline B cell as well as T cell tumorigenesis.

Aging↗

PubMed1995

Expression of a novel receptor for the calcitonin peptide family and a salmon calcitonin-like peptide in the alpha-thyrotropin thyrotroph cell line.

We have previously shown an increased incidence of alpha-subunit-producing thyrotroph tumors after salmon calcitonin (sCT) injection into rats. However, it is not clear whether the effects of CT are direct or indirect. Our hypothesis was that for sCT to act directly, it must have a binding site on thyrotrophs. The alpha TSH cell line was used as a model for thyrotrophs. Receptor binding studies using alpha TSH membranes revealed a high affinity binding site for sCT [IC50 = 0.97 +/- 0.18 nM (n = 4); Kd = 5.45 +/- 0.43 nM (n = 3); binding capacity = 6.6 pmol/mg protein (n = 3)]. Rat CT did not compete with binding at this site. Receptor screening for other CT peptide family members revealed high specific binding for CT gene-related peptide (CGRP; IC50 = 0.25 +/- 0.08 nM; n = 3) and islet amyloid polypeptide (IC50 = 4.36 +/- 1.1 nM; n = 3). This together with the absence of rat CT binding excluded a conventional CT-binding site, and we propose a site similar to the CGRP subtype III receptor described in the rat nucleus accumbens. Guanosine 5'O-(3-thiotriphosphate) (GTP gamma S) (20 microM), reduced [125I]CGRP binding to 38% of maximal, indicating that this site is G-protein coupled. Immunocytochemically, all of the cells displayed intense sCT-like immunoreactivity, which was totally abolished by preabsorption of the antibody with sCT. The presence of this receptor supports the hypothesis that sCT mediates tumorigenesis via a direct pituitary action and, together with the coexistence of a sCT-like peptide in these cells, provides evidence for a possible autocrine role of this peptide in the control of thyrotroph function.

Amyloid↗

PubMed1994

Cutaneous T-cell lymphoma in a cat.

An 8-year-old castrated male cat was examined because of a chronic, nonhealing, ulcerative lesion on the left hind limb. Cutaneous lymphoma was diagnosed on the basis of the morphologic appearance of malignant cells and Pautrier's microabscesses on light and electron microscopic examination. The tumor was found to be of T-cell origin by use of a polyclonal antibody recognizing T-cell antigen. Results of serum ELISA for FeLV were negative. The gp70 antigen of FeLV was not detected immunohistochemically in tumor tissue sections, using polyclonal goat antisera and avidin/biotin/peroxidase complex technique. Presence of FeLV was demonstrated by the polymerase chain reaction procedure, involving amplification of a 166-base pair region of FeLV DNA. Although FeLV is reported to be the cause of most types of lymphoma in cats, cats with epitheliotropic cutaneous lymphoma have consistently negative test results for circulating FeLV antigen. In such cases, using the polymerase chain reaction method, tumor DNA may be assessed for integrated FeLV provirus and the presence of FeLV can be confirmed.

Animals↗

PubMed1993

Feline leukemia virus detection by immunohistochemistry and polymerase chain reaction in formalin-fixed, paraffin-embedded tumor tissue from cats with lymphosarcoma.

The prevalence of feline leukemia virus (FeLV) antigen and DNA was assessed in formalin-fixed, paraffin-embedded tumor tissues from 70 cats with lymphosarcoma (LSA). Tissue sections were tested for FeLV gp70 antigen using avidinbiotin complex (ABC) immunohistochemistry (IHC); DNA was extracted and purified from the same tissue blocks for polymerase chain reaction (PCR) amplification of a 166 base pair region of the FeLV long terminal repeat (LTR). Results were related to antemortem FeLV enzyme-linked immunosorbent assay (ELISA) for serum p27 antigen, anatomic site of LSA, and patient age. Viral DNA was detected by PCR in 80% of cases and viral antigen by IHC in 57% of cases. Seventeen cases were PCR-positive and IHC-negative; one case was PCR-negative and IHC-positive. Clinical records included FeLV ELISA results for 30 of 70 cats. All 19 ELISA-positive cats were positive by PCR and IHC; of the 11 ELISA-negative cats that were negative by IHC, seven were positive by PCR. When evaluated according to anatomic site, FeLV DNA and antigen were detected less frequently in intestinal LSAs than in multicentric and mediastinal tumors. Lymphosarcoma tissues from cats < 7 yr were several fold more likely to be positive for FeLV antigen by IHC than were tumors from cats > or = 7 yr. However, there was no significant difference in PCR detection of FeLV provirus between LSAs from cats < 7 yr and those > or = 7 yr.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Prekallikrein deficiency in a family of Belgian horses.

A 7-year-old Belgian stallion hemorrhaged excessively after castration; the hemostatic mechanism was investigated. The horse had normal one-stage prothrombin time and markedly prolonged activated partial thromboplastin time (APTT). Results of intrinsic coagulation factor assays were all normal with the exception of prekallikrein activity, which was markedly reduced (less than 1% activity; value for control population, 63 to 150%). Two of this horse's full siblings, a brother and sister, had markedly prolonged APTT and low prekallikrein values (2.5% and less than 1%, respectively). The addition of plasma from a normal equine plasma pool corrected the prolonged APTT in the 3 Belgian sibling with low prekallikrein activity. Prekallikrein activity in 10 other closely related Belgian horses ranged between 12.5 and 64% (mean, 29.3%), compared with 63 to 150% (mean, 91%) in 10 mixed-breed horses. In the 3 Belgian siblings with low prekallikrein activity, the APTT approached normal after prolonged incubation (15 minutes) with the contact activator and in response to addition of an ellagic acid activator. The 3 Belgian siblings with low prekallikrein activity may be homozygous for prekallikrein deficiency, whereas the other close relatives may be heterozygous for the genetic defect.

Animals↗

PubMed1989

Whole blood platelet aggregation in dogs with liver disease.

Whole blood platelet aggregation was determined in response to collagen, arachidonic acid, and adenosine diphosphate in 20 dogs with liver disease and in 20 control dogs. Platelet aggregation in response to collagen and arachidonic acid was reduced in dogs with liver disease, compared with control dogs (P less than 0.05), whereas there was no significant difference in platelet response to adenosine diphosphate between the 2 groups of dogs. Adenosine diphosphate was found not to be a reliable aggregation agent for determination of whole blood platelet aggregation in dogs. Dogs whose platelets did not aggregate in response to collagen and/or arachidonic acid manifested bleeding tendencies that could be attributed to platelet dysfunction.

Adenosine Diphosphate↗

PubMed1989

Whole blood platelet aggregation in uremic dogs.

Whole blood platelet aggregation responses to collagen, arachidonic acid, and adenosine diphosphate were determined by use of the impedance method in 22 dogs with serum urea concentrations greater than or equal to 20 mmol/L, which was attributable to renal disease, and in 25 healthy control dogs. The median changes in impedance for the control dogs were 23 ohms for collagen, 18 ohms for arachidonic acid, and 6 ohms for adenosine diphosphate. The median changes in impedance in uremic dogs were 25 ohms for collagen, 21 ohms for arachidonic acid, and 15 ohms for adenosine diphosphate. There were no significant differences in platelet aggregation responses to collagen, arachidonic acid, and adenosine diphosphate between uremic and control dogs. Hemorrhagic tendencies were not detected in uremic dogs by use of whole blood platelet aggregation. Results of this study suggest that platelet aggregation by use of the whole blood platelet aggregometer is not abnormal in uremic dogs, but does not exclude the possibility of a platelet aggregation defect undetected by the whole blood system.

Adenosine Diphosphate↗

PubMed1988

Diagnostic value of alkaline phosphatase isoenzyme separation by affinity electrophoresis in the dog.

Affinity electrophoresis, using wheat germ lectin, was used to separate the alkaline phosphatase isoenzymes in the sera of 150 dogs with alkaline phosphatase values greater than or equal to 150 IU/L. The method provided clearer separation of the liver, bone and steroid-induced alkaline phosphatase isoenzymes commonly observed in canine serum, compared to conventional cellulose acetate electrophoresis. The dogs were divided into four patient groups determined by previous corticosteroid treatment, evidence of elevated endogenous corticosteroid levels, age and alanine aminotransferase values. The isoenzyme pattern of each patient was qualitatively assessed. The isoenzyme pattern most frequently observed was greater than 50% steroid induced alkaline phosphatase, which was present in 76 of 150 dogs. This pattern was observed in 18 of 22 dogs receiving corticosteroid therapy, two of three dogs with hyperadrenocorticism, and in dogs with a variety of other diagnoses. The majority of immature dogs (12 of 20) had an isoenzyme pattern consisting of greater than 50% bone. The majority of dogs with active hepatocellular injury (16 of 27) had greater than 50% liver isoenzyme. The isoenzyme pattern was not specific for certain diseases, therefore the diagnostic usefulness is limited. However the isoenzyme result is useful in some cases to determine which further diagnostic tests are indicated, and to determine the source of alkaline phosphatase elevation.

Adrenal Cortex Hormones↗

PubMed1986

The offensive wrist.

Fencing between injection of Tc-99m MDP and imaging resulted in a diffuse increase in radioactivity in the asymptomatic wrist of a right-handed fencer. Repeat study two weeks later showed normal distribution of radiopharmaceutical. At that time, the athlete was fenced into the patient waiting area between injection and scan.

Adult↗

PubMed1986

Effects of polynucleotide inhibitors on transcriptional events of influenza virions.

Polynucleotide inhibitors of the influenza virion transcriptase, which is activated in vitro by detergent, can be divided into two categories. Polyribonucleotides comprised of adenine and guanine bases or adenine and uracil bases inhibit initiation but not elongation events of transcription. In contrast, polyribonucleotides containing cytidine and uracil or inosine and uracil block both initiation and elongation. Effects on elongation are apparent on addition of polynucleotides at either 5 or 10 min post-initiation. Dose-response studies with these and other polynucleotides have shown that the concentrations causing 50% inhibition of transcription vary considerably with the most potent inhibitor being the modified polymer, poly(C,S4U10).

Orthomyxoviridae↗

PubMed1986

Effect of patient positioning on liver size estimation.

Technetium sulfur colloid imaging is widely regarded as a simple, accurate technique for the evaluation of liver size. Although numerous strategies have been proposed for standardizing measurements, none has considered the possibility of a variation depending on whether the patient is imaged erect or recumbent. We imaged several patients in both positions and observed an apparent increase in the vertical length of the liver from supine to upright. We confirmed this by demonstrating a significant increase in the vertical length of both the right and left lobes in a majority of 55 patients imaged in both positions.

Hepatomegaly↗

PubMed1985

Rhodopsin-egg phosphatidylcholine reconstitution by an octyl glucoside dilution procedure.

The transmembrane protein bovine rhodopsin was reconstituted with egg phosphatidylcholine (PC) by using a modified detergent dilution technique employing the nonionic detergent octyl-beta-D-glucoside (octyl glucoside). Using this technique, reconstituted membranes having molar phospholipid/protein ratios between 60:1 and 255:1 were prepared. This is in contrast to the results obtained when an octyl glucoside dialysis technique was employed (Jackson, M.L. and Litman, B.J. (1982) Biochemistry 21, 5601-5608). In the latter case, the highest molar phospholipid/protein ratio that could be obtained when reconstituting rhodopsin with egg PC was approximately 50:1. Reconstituted vesicles prepared by the octyl glucoside dilution technique were examined by negative stain and freeze-fracture electron microscopy, and it was found that the vesicles were unilamellar providing the molar PC/protein ratio was below about 200:1, whereas in preparations having ratios higher than this, a significant number of the vesicles were multilamellar. The mean vesicle diameter showed no trend based on the molar PC/protein ratio within the range of 82:1 to 186:1. The mean diameters of the preparations were between 520 and 850 A. Approximately equal numbers of protein particles were observed on the concave and convex fracture faces of the freeze-fracture micrographs of the reconstituted membranes which is indicative of a symmetric distribution of the protein across the bilayer.

Centrifugation, Density Gradient↗

PubMed1985

Radioimmunoassay for detection of VP1 specific neutralizing antibodies of foot and mouth disease virus.

A solid-phase radioimmunoassay was developed for the detection of antibodies against a specific region of the VP1 protein of the A24 and 01 serotypes of foot and mouth disease virus. The antibody titers from the radioimmunoassay showed a positive correlation with neutralizing antibody titers determined by a mouse protection assay. The specificity of the assay resides in the peptide used as antigen. The assay is rapid, reproducible and does not require the use of whole virions.

Animals↗