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Biomedical subjects

J Pollock

Publications and source records attributed to J Pollock.

67 records · Page 4Linked to original sources
PubMed1977

Rh isoimmunization, Manitoba, 1963-75.

The number of Rh-isoimmunized pregnancies in Manitoba has been reduced from 223 and 228 in the years ending Oct. 31, 1963 and 1964 to 60 and 62 in the years ending Oct. 31, 1974 and 1975. The number per 1000 total births in the same years has decreased from 10.0 and 10.6 to 3.4 and 3.5 Perinatal mortality rates in those years decreased from 13.8 amd 15.7% to 0 and 2.2%, respectively. The number of perinatal deaths has been reduced from 55 in the first 2 years reported to 1 in the last 2 years. Among the 121 isoimmunized women pregnant in the 2-year period ending Oct. 31, 1975, isoimmunization was due to failure to give Rh immune globulin after delivery in 33 and failure to give it during pregnancy in 48. Of the remaining 40, 37 were immunized before Rh immune globulin became available. Complete prevention of Rh isoimmunization and therefore of all perinatal deaths from Rh erythroblastosis can only be achieved through universal Rh testing prenatally and immediately after delivery, and institution of an antenatal Rh prophylaxis program.

Antibody Formation↗
PubMed1977

Relationship of serum theophylline concentration to inhibition of exercise-induced bronchospasm and comparison with cromolyn.

Exercise-induced bronchospasm was induced by treadmill running in 12 children on two days preceding either inhaled cromolyn sodium (Intal) or oral theophylline (Slo-Phyllin tablets), 7.5 mg/kg, administered in a double-blind manner. A second exercise period identical to the first followed two hours later; the medication administration had been timed so that the second exercise stress followed two hours after theophylline administration and 15 minutes following cromolyn administration. The patients subsequently were exercised twice more at two-hour intervals on both days. Blood was drawn from serum theophylline measurement immediately after each of the exercise periods. There was little demonstrable exercise-induced bronchospasm resulting from the first postmedication exercise period following theophylline administration. The two subsequent exercise periods were associated with some return of postexercise bronchospasm. The degree of inhibition of exercise-induced bronchospasm correlated with serum theophylline levels that averaged 16, 13, and 10 microgram/ml at two, four and six hours after the theophylline dose (mean Spearman rank correlation coefficient = .71, P less than .01). The effect of cromolyn in suppression exercise-induced bronchospasm that matched or excelled that seen with theophylline.

Adolescent↗
PubMed1975

An error in Rh testing in pregnancy.

Anti-D (anti-Rho) in the blood of two Rh-negative pregnant women was believed to be due to active immunization. In the first case, however, antibodies were no longer detectable 2 weeks later. In the second case they disappeared by the end of 31 weeks. It was discovered that both women had been given immune globulin (human) because of exposure to rubella. The globulin given to the first woman probably contained about 0.1 mug of anti-D per ml; that given to the second probably contained about 0.6 mug of anti-D per ml. Both babies were O Rh-positive. Both women were given Rh immune globulin after delivery. Both have completed a further pregnancy and no anti-D has been found on many tests. In tests carried out in 1971 all samples of immune globulin (human) examined contained anti-D, but usually in inconsequential trace amounts.

Diagnostic Errors↗
PubMed1970

The effect of anti-D IgG on D-positive recipients.

When one standard prophylactic dose of anti-Rh(D) immunoglobulin (Connaught) (and in one case two doses) was injected into 15 D-positive volunteers it caused no reaction and no measurable alteration in readings of hemoglobin, hematocrit, reticulocytes or bilirubin, although some of the volunteers briefly became weakly direct Coombs'-positive. It is argued that since any isohemagglutinin that may contaminate anti-D IgG must be much less in amount than the anti-D it contains, the contaminating antibody cannot carry a greater potential for harm to a recipient having the corresponding antigen than the anti-D for a D-positive recipient, which is zero. It is suggested that the presence of anti-DC or G in so-called anti-Rh(D) IgG may, in fact, be a mark of excellence. The application of these facts to selection of plasma donors and to tests required before giving prophylactic treatment to women is briefly stated.

Adult↗
PubMedDate not supplied

Metabotropic glutamate receptor activation and intracellular cyclic ADP-ribose release Ca2+ from the same store in cultured DRG neurones.

The whole cell patch clamp technique has been used to record Ca(2+)-activated cation and chloride conductances evoked by release of Ca2+ from intracellular stores of cultured neonatal dorsal root ganglion neurones. The aim of this study was to investigate metabotropic glutamate receptor (mGluR) mechanisms and evaluate a possible role for cyclic ADP-ribose as an intracellular signalling molecule. Glutamate and the metabotropic glutamate receptor agonist (1S, 3R)-ACPD-evoked transient depolarizations, Ca(2+)-activated inward currents and rises in intracellular Ca2+. The (1S, 3R)-ACPD-activated currents were insensitive to InsP3 signalling inhibitors, heparin and pentosan polysulphate. Intracellular application of ryanodine alone activated currents in this study and proved a difficult tool to use as a potential inhibitor of cyclic ADP-ribose-mediated responses. However, intracellular dantrolene did attenuate both (1S, 3R)-ACPD and cyclic ADP-ribose responses. Intracellular photo-release of cGMP and cyclic ADP-ribose mimicked the responses to mGluR receptor activation. Intracellular application of nicotinamide and W7 inhibited the responses to photo-released cGMP but did not prevent responses to mGluR activation. The cyclic ADP-ribose receptor antagonist 8-amino cyclic ADP-ribose attenuated responses to (1S, 3R)-ACPD, cGMP and cyclic ADP-ribose, but some Ca(2+)-activated inward currents were still observed in the presence of this antagonist. In conclusion, mGluR receptor activation, cGMP and cyclic ADP-ribose release Ca2+ from intracellular stores. Some evidence suggests that pharmacologically related pathways are involved.

Adenosine Diphosphate Ribose↗
PubMedDate not supplied

Release of daunorubicin from polymethylmethacrylate for the improvement of the local growth control of bone metastasis animal experiments.

Bone metastases are a sign of advanced tumor disease. Surgical therapy is only occasionally curative. Therefore, the therapeutic goals are a limited surgical excision, immediate mobilization, effective stabilization and the avoidance of local recurrence. We investigated the effect of the anthracycline daunorubicin (DNR) in conjunction with polymethylmethacrylate (PMMA) in vitro and in animal experiments for regional control of bone metastases. Previous experiments of local chemotherapy in bone metastases using methotrexate (MTX) were done by Langendorff and Hernigou. In our own experiments we improved the release of daunorubicin from polymethylmethacrylate in vitro and in vivo up to 90% by adding mannitol. In in vivo experiments we investigated the combination of DNR and PMMA in athymic nude mice and Wistar rats. Cells from human breast cancer, bronchial carcinoma, nephroma, and soft tissue sarcoma were subcutaneously implanted bilaterally under the dorsal skin of nude mice. After reaching a diameter of 0.5 cm, the tumors were marginally excised, leaving microscopic tumor residuum behind. The tumor cavities were either filled with PMMA or alternatively with DNR-PMMA. The goal was to avoid tumor recurrence in the DNR-PMMA filled resection cavities. The number of recurrences was significantly lower in the DNR-PMMA treated animals, except in the breast cancer group. Additionally we implanted a rat sarcoma intrafemorally into Wistar rats. After 17 days the tumor was marginally excised and the resection cavity was filled with either DNR-PMMA or PMMA alone. The therapeutic goal was to prevent local recurrence. Histological and pharmacological tests concerning toxicity and drug distribution within the body completed the study. We concluded that the addition of daunorubicin to PMMA supplements surgical resection. We were able to reduce the number of, or delay recurrences in our animal models. Systemic side effects could be minimized despite the achievement of high local drug concentrations.

Animals↗