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Biomedical subjects

J Burns

Publications and source records attributed to J Burns.

At least 361 records · Page 20Linked to original sources
PubMed1988

Progress towards cloning the cystic fibrosis gene.

Genetic linkage analysis with polymorphic DNA markers (restriction fragment length polymorphisms: RFLPS) has allowed the assignment of the cystic fibrosis (CF) locus to the long arm of chromosome 7, within the region of band q31. Two of these markers, MET and D7S8, are tightly linked to the disease locus. Although recent data suggest that they are located on opposite sides of CF, the two can be separated by as much as 5 centimorgans. To obtain a better description of the CF locus and, eventually, to identify the affected gene, additional DNA markers are required to connect MET and D7S8, physically. We have screened the flow-sorted chromosome-7-specific library and thus far isolated 28 new probes from the 7q31 region by DNA hybridization analysis that uses a series of somatic cell hybrids containing various portions of human chromosome 7. Together with the previously identified markers, MET, D7S8, D7S13 and D7S16, these new markers should provide a fine genetic and physical map for the chromosomal region surrounding CF. DNA segments can then be sequentially cloned by chromosome walking from points closest to the CF locus and examined for genes that are preferentially expressed in tissues known to be affected in the disease.

Animals↗
PubMed1988

Direct visualization of single copy genes on banded metaphase chromosomes by nonisotopic in situ hybridization.

A rapid method is described for non isotopic in situ mapping of single copy genes directly on G-banded chromosomes by "one-step" regular light microscopy. It is based on hybridizing biotinylated probes to metaphase chromosomes. Biotin residues are detected by rabbit antibiotin antibody and anti-rabbit Ig labelled with peroxidase or colloidal gold. The peroxidase reaction product or colloidal gold signals are amplified by silver precipitation. The final product is a black silver dot at the gene locus on a purple G-banded chromosome. N-ras and alpha-1-antitrypsin genes have been mapped using plasmids with inserts of 1.5 and 1.3kb to 1p13.1 and the junction of 14q31/32 respectively. The signal to noise ratio in these experiments ranged from 32:1-46:1. This technology is at least as sensitive as radioisotopic in situ hybridization and gives results within 1 day of hybridization and has much better resolution. Additionally, genes are visualized by regular light microscopy without specialized techniques such as reflection contrast, fluorescence or phase microscopy. This methodology should facilitate more precise chromosomal gene localization.

Cells, Cultured↗
PubMed1988

Tolerance of engrafted donor T cells following bone marrow transplantation for severe combined immunodeficiency.

Patients transplanted for the treatment of severe combined immunodeficiency (SCID) frequently develop a unique state of split lymphoid chimerism. Such patients have T cells of donor origin, and non-T cells which are predominantly or exclusively of host origin. We have studied the reactivity of engrafted donor T cells to host and/or donor antigens in 12 patients transplanted for SCID, focusing on the characteristics of the tolerance to host and/or donor MHC antigens observed in nine of these patients who were recipients of T-cell-depleted, haploidentical parental bone marrow. In both proliferative and cytolytic assays, engrafted, donor-derived T cells were shown to be selectively nonreactive to histoincompatible host cells. This tolerance could not be ascribed to cells with suppressive activity in the engrafted T-cell population. T cells from a subset of patients, however, exhibited proliferative but not cytolytic reactivity to donor peripheral blood mononuclear cells. The responding cells were shown to be donor-derived CD3+ cells and were predominantly reactive to B-cell fractions from the donor. Two patients who received transplants from each parent in sequence engrafted T cells from one parent and had non-T cells of host, paternal, and maternal origin. The engrafted T cells proliferated weakly to B cells from the other parent, but were tolerant in cytolytic assays. Donor anti-donor reactivity was seen only in haploidentical split chimeras who had not been treated with cytotoxic drugs prior to T-cell engraftment. This proliferative reactivity toward donor may be due to an absence of donor derived Ia+ antigen presenting cells resident in the thymus of SCID patients at the time when the T-cell repertoire is being shaped.

B-Lymphocytes↗
PubMed1988

Afferent fibers in the reproductive system and pelvic viscera of female rats: anterograde tracing and immunocytochemical studies.

Innervation of the female reproductive system provides an important signal for a variety of neuroendocrine reflexes and behaviors in the female rat. Although some studies suggest that afferent feedback from the gonads is involved in the hypothalamic control of gonadal function and pituitary hormone release, the extent and function of afferent feedback from the gonads in these neuroendocrine reflexes has yet to be clarified. Deafferentation studies have provided only partial support for the afferent control of the gonads. Some studies even suggest functional asymmetries in the neural control of the gonads, but knowledge regarding the neuroanatomical substrate for these possible neurogonadal interactions remains incomplete. Studies with retrograde tract tracers indicate that the ovaries receive a substantial afferent supply from lower thoracic-upper lumbar dorsal root ganglia. Despite stringent precautions to prevent diffusion of tracers following injections into the ovary or related nerves, many of the retrogradely labeled cell bodies identified by these studies may represent an overestimation of the extent of afferent innervation. We have reexamined the afferent innervation of the female reproductive tract by means of the anterograde transport of horseradish peroxidase (HRP) from thoracic, lumbar and sacral dorsal root ganglion to pelvic visceral organs and have studied the effects of unilateral ganglionectomy on substance P containing fibers in the ovary, oviduct and uterus. The neuroanatomical results show that the T13 and L1 dorsal root ganglia provide major afferent innervation to the cranial portion of the reproductive tract and the L6 and S1 dorsal root ganglia provide primary afferent fibers to the caudal portion of the reproductive tract as well as the bladder, rectum and perineum.(ABSTRACT TRUNCATED AT 250 WORDS)

Afferent Pathways↗
PubMed1988

Differential recovery of phenotypically and functionally distinct circulating antigen-presenting cells after allogeneic marrow transplantation.

Low-density cells (LDC) prepared from peripheral blood by fractionation over hypertonic metrizamide contain 95% of cells with veiled morphology, almost all of which are HLA-DR-positive and have characteristics of antigen-presenting cells. In normal individuals the monoclonal antibodies RFD1 and RFD2 divide these cells into three phenotypically distinct populations, D1+D2-, D1-D2+ and D1-D2-. The RFD1-positive population is nonphagocytic. We have investigated the recovery of LDC in peripheral blood after (T cell-depleted) marrow transplantation, to assess whether defects in antigen-presenting cell (APC) subpopulations could contribute to the prolonged immune-paresis of marrow graft recipients. We find that APC of donor origin and with apparently normal morphology, phenotype, and function appear within 6 weeks of BMT. By three months the donor-derived nonphagocytic RFD1-positive subset has disappeared, although phagocytic RFD2-positive cells remain. The disappearance of the RFD1-positive subset is associated with a loss of antigen presentation by patients' LDC of the soluble protein antigen tetanus toxoid, though the capacity to present alloantigen and stimulate in a mixed lymphocyte reaction is retained. Donor-derived RFD1-positive cells and soluble antigen-presenting capacity do not reappear for one year or more. This biphasic recovery of RFD1-positive cells contrasted with the continued production of RFD2-positive APC, implies that the phenotypic and functional distinction between APC subpopulations in peripheral blood also reflects a separate ontogeny. Since these marrow graft recipients retain the phagocytic (RFD2-positive) APC but lose the nonphagocytic (RFD1-positive) APC subset, there is now an opportunity to explore the role of each subset in antigen processing and presentation.

Adolescent↗
PubMed1988

Monoclonal antibody EBM/11: high cellular specificity for human macrophages.

A monoclonal antibody, EBM/11, was raised against isolated human lung macrophages. Immunohistochemically this antibody reacted with freshly isolated lung macrophages and blood monocytes, mononuclear cells (presumptive macrophages) in sections of lung, skin, stomach, small and large bowel, pancreas, spleen, tonsil, placenta, liver, gall bladder, heart, thyroid, pituitary, brain, and peritubular and mesangial cell in kidney. Microglial cells and osteoclasts also labelled with EBM/11. The antibody reacted with cytoplasmic structures rather than with cell membranes. The epitope recognised by EBM/11 was present on four polypeptides (of 120, 70, 64 and 22 kilodaltons). It did not react with any other cell type in the tissues screened except the epithelium of renal proximal tubules. This antibody may be useful in identifying and elucidating the function of macrophages in pathological processes.

Antibodies, Monoclonal↗
PubMed1988

Histological analysis of parotid and submandibular glands in chronic alcohol abuse: a necropsy study.

A quantitative histological analysis of the major salivary glands was carried out at necropsy in 28 alcoholics and in a series of age and sex matched controls. The findings were related to the different types of histologically diagnosed liver disease present. Significant quantitative changes of salivary gland structure were noted in cirrhosis but not in other forms of alcoholic liver disease. In cirrhotic subjects the parotid contained proportionally more adipose but less acinar tissues than in controls. The submandibular gland showed a proportional increase in adiposity and reduction in fibrovascular tissues but no noticeable reduction in its acinar proportional volume. Neither grossly detectable parotid enlargement nor acinar hypertrophy, a feature which has previously been noted as characteristic of alcoholic sialadenosis, were evident in this series. These findings provide little structural support for the reportedly increased secretory capacity of salivary glands in chronic alcohol abuse.

Adipose Tissue↗
PubMed1988

Non-isotopic detection of in situ nucleic acid in cervix: an updated protocol.

Recently, sensitive non-isotopic in situ hybridisation (NISH) methodology for the detection of human DNA and human papilloma virus (HPV) DNA in archival paraffin blocks of cervix was described. An amended protocol, now used in this laboratory for detection of these genes by NISH is presented. The amendments include the following: protease digestion at 37 degrees C; tissue dehydration in air rather than ethanol; stringency washing in formamide solution; blocking non-specific binding of avidin alkaline phosphatase with a modified buffer; and increasing the concentration of avidin alkaline phosphatase for detecting low abundance DNA. These changes simplify and increase the sensitivity of the protocol such that "Y" chromosome repeats are visualised in almost all female cells.

Cervix Uteri↗
PubMed1988

Identification and regional localization of DNA markers on chromosome 7 for the cloning of the cystic fibrosis gene.

To facilitate mapping of the cystic fibrosis locus (CF) and to isolate the corresponding gene, we have screened a flow-sorted chromosome 7-specific library for additional DNA markers in the 7q31-q32 region. Unique ("single-copy") DNA segments were selected from the library and used in hybridization analysis with a panel of somatic cell hybrids containing various portions of human chromosome 7 and patient cell lines with deletion of this chromosome. A total of 258 chromosome 7-specific single-copy DNA segments were identified, and most of them localized to subregions. Fifty three of these corresponded to DNA sequences in the 7q31-q32 region. Family and physical mapping studies showed that two of the DNA markers, D7S122 and D7S340, are in close linkage with CF. The data also showed that D7S122 and D7S340 map between MET and D7S8, the two genetic markers known to be on opposite sides of CF. The study thus reaffirms the general strategy in approaching a disease locus on the basis of chromosome location.

Animals↗
PubMed1988

Myocardial performance after repair of congenital cardiac defects in infants and children. Response to volume loading.

The hemodynamic response to increasing left atrial pressure by volume loading was evaluated in 70 children during the first 24 hours after repair of congenital cardiac defects. The children were grouped into four diagnostic categories: atrial septal defect or pulmonary valve stenosis (n = 8), ventricular septal defect (n = 36), complete transposition after Mustard's operation (n = 13), and tetralogy of Fallot (n = 13). Within 2 hours of bypass, both cardiac index and left ventricular stroke work index were adequate and increased appropriately with volume loading in all four diagnostic groups. The atrial septal defect group demonstrated a similar response to volume loading 4 and 24 hours after bypass. However, the other three diagnostic groups had a higher filling pressure, lower cardiac index and stroke work index, and a depressed response to increasing preload 4 hours postoperatively, which indicated a deterioration in cardiac performance. The deterioration was maximal between 4 and 12 hours after bypass, and performance tended to recover 24 hours postoperatively. The transposition group had a more profound depression in cardiac performance than the other two groups. Within the ventricular septal defect group, smaller children (body surface area less than 0.36 m2) had a more profound depression in performance than larger children. These results demonstrate a significant alteration in cardiac performance during the first 24 hours after repair of congenital cardiac defects in children. These changes should be considered when postoperative management is being planned.

Cardiac Output↗
PubMed1988

Use of a flexible catheter for tubal lavage in infertility surgery.

A flexible catheter originally designed for hysterosalpingography was used for intraoperative tubal lavage in 15 patients undergoing various infertility procedures. The catheter was easily inserted without the use of a tenaculum or cervical dilators, provided reliable dye instillation, and offered an alternative to the pediatric Foley or Buxton clamp.

Catheterization↗
PubMed1987

Diagnosis of gestational diabetes by capillary blood samples and a portable reflectance meter: derivation of threshold values and prospective validation.

Paired capillary-venous samples were obtained from 255 women undergoing a glucose challenge test and 116 women undergoing an oral glucose tolerance test. The capillary equivalents for the venous threshold values were calculated by regression analysis. The glucose challenge test predictions of either normal or abnormal agreed in 82%. The sensitivity, specificity, and positive and negative predictive values for the capillary oral glucose tolerance test were 89%, 90%, 62%, and 98%, respectively. These capillary equivalents were then applied prospectively to 147 women undergoing a glucose challenge test and 141 women undergoing an oral glucose tolerance test. The concurrence rate of the glucose challenge test in the prospective group was 90%. The sensitivity, specificity, and positive and negative predictive values for the capillary oral glucose tolerance test were 64%, 95%, 75%, and 92%. When the venous threshold recommendations of the American Diabetes Association were used instead of those standard at our institution, these values increased to 75%, 98%, 83%, and 96%, respectively. The recommended capillary values of the American Diabetes Association were 100% sensitive but had a positive predictive value of only 20%. Based on the prospective group, the cost per case of gestational diabetes identified would decline 63% if both a capillary glucose challenge test and an oral glucose tolerance test were used and 25% if the capillary glucose challenge test and venous oral glucose tolerance test were used. Combining the data set for new regression equations, the following venous-capillary threshold sets emerged: glucose challenge test, 140 mg/dl/150 mg/dl; fasting oral glucose tolerance test, 105 mg/dl/114 mg/dl; 1 hour, 190 mg/dl/211 mg/dl; 2 hours, 165 mg/dl/183 mg/dl; 3 hours, 145 mg/dl/157 mg/dl. The sensitivity, specificity, and negative predictive values for the capillary oral glucose tolerance test with these thresholds were 80%, 97%, 80%, and 97%. In conclusion, capillary glucose testing for diabetes during pregnancy is feasible and cost-effective.

Blood Glucose↗
PubMed1987

Human fetal breathing response to intravenous glucose is directly related to gestational age.

This prospective longitudinal study examined human fetal breathing activity over the second half of pregnancy both in the fasting state and after intravenous glucose administration. There was a linear relationship between gestational age and percent time spent breathing after glucose between 19 and 38 weeks' gestation. However, no such correlation could be demonstrated between gestational age and fetal breathing activity in the fasting state.

Embryonic and Fetal Development↗
PubMed1987

The morphine sparing effects of diclofenac sodium following abdominal surgery.

A randomised, double-blind placebo controlled study was undertaken to assess the analgesic efficacy of diclofenac. Following major abdominal surgery and 12 hours later, patients received either placebo or diclofenac 75 mg intramuscularly and their cumulative morphine requirements administered by a patient-controlled system over 24 hours were compared. Pain scores were also measured. Arterial blood gases and coagulation studies were assessed pre- and postoperatively. Morphine consumption was significantly greater in the placebo group (59.5 compared to 38.5 mg, p less than 0.01). Pain scores were significantly lower in the diclofenac group at 4 hours, but not thereafter. Arterial carbon dioxide was significantly increased in the control groups. There was no significant change in platelet count within each group, but a significant difference between the groups (p less than 0.05).

Abdomen↗
PubMed1987

A quantitative study of histological changes in the human parotid gland occurring with adult age.

Parotid samples from 63 'sudden death' necropsies of both sexes, aged 17-90 years, were collected after exclusions for chronic illness or medications. Advancing age was accompanied by acinar atrophy and ductal irregularities. The adipose content varied widely at all ages but, together with fibrovascular tissue, tended to increase with age. Stereological analysis demonstrated a linear reduction of acinar proportional volume amounting to 30% over the age range. Females tended to have more adipose tissue and less fibrous tissue than males. These structural age changes resemble those of other salivary glands, but unlike the latter are not accompanied by age-dependent functional impairments. This suggests a greater acinar secretory efficiency or larger secretory reserve volume in the parotid than in other glands. The frequent high levels of parotid adiposity encountered suggest this feature is not pathological nor necessarily a reliable indicator of nutritional or hormonal diseases, excluded from the present study.

Adipose Tissue↗
PubMed1987

Detection of low copy human papilloma virus DNA and mRNA in routine paraffin sections of cervix by non-isotopic in situ hybridisation.

In analysing human papilloma virus (HPV) infection of the cervix in formalin fixed paraffin sections by non-isotopic in situ hybridisation two main problems were found: detachment of sections from the glass during hybridisation and probe detection; inadequate sensitivity and inability to assess sensitivity of the in situ procedure. The first problem was investigated by assessing the efficiency of various tissue adhesives individually and in combination. The second problem was addressed by optimising conditions for DNA unmasking, hybridisation, and biotinylated probe detection. Sensitivity of the final in situ procedure developed was assessed by using the detection of pHY2.1 repeats as a built-in control. Extrapolation of data showed that less than 10 copies of HPV DNA can be visualised by these procedures. HPV nucleic acid, mainly in the form of DNA, was detected not only in koilocytic nuclei but also in suprabasal cells in condylomas and CIN lesions. HPV mRNA was also visualised in the cytoplasm (and probably also nuclei) of the same cell types. These non-isotopic in situ procedures give results comparable to those obtained with radiolabelled probes, but they are less time consuming and provide better morphological resolution.

Cervix Uteri↗