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Biomedical subjects

J R Matthews

Publications and source records attributed to J R Matthews.

At least 55 records · Page 3Linked to original sources
PubMed1979

The proliferative activity of leukaemic myeloblasts following the intravenous infusion of cytarabine.

Serial bone marrow aspirates were obtained from 16 adults with acute myeloid leukaemia (AML) before and after a single infusion of cytarabine (5.0 mg/kg i.v. over 30 min). Changes in the proliferative activity of the leukaemic myeloblasts were monitored by determination of the labelling index (LI) and the mitotic index (MI). There was a significant fall in both LI and MI within a few hours of the administration of cytarabine (P = 0.005). In 14 of the 16 cases the LI subsequently rose to observed maxima 0.3% to 14.1% (mean 5.0%) above the preinfusion LI, 11 to 77 hours (mean 40.8 h) after the infusion (P less than 0.05). The MI returned to the mean pretreatment level within the period of observation in 11 of the 16 cases. In general, the changes in MI followed those in LI; the results are consistent with cytarabine-induced arrest or death of leukaemic blast cells in S phase. Because of the variability in timing of kinetic changes in leukaemic myeloblasts following cytarabine, it is not possible to institute remission induction therapy consistently at the time of maximum synchronization with any fixed chemotherapeutic schedule. Furthermore, the degree of synchronization attained is, in general, small, limiting the prospect of exploiting synchronization with cytarabine as a means of improving the remission rate for AML.

Adolescent↗
PubMed1979

The prevalence and nature of anemia among apparently normal subjects in Fiji.

A total of 4939 apparently healthy Fijian and Indian subjects living in Fiji were tested for anaemia by determination of the microhaematocrit of a sample of capillary blood. The prevalence of anaemia during childhood varied with age but was similar for Fijians and Indians of either sex. The overall prevalences were: 0-4 years, 20.3%; 5-9 years, 3.7%; 10-14 years, 23.5%. The prevalence of anaemia among Indian women (33.3%) was substantially higher than that for Indian men (6.9%), Fijian women (8.1%) or Fijian men (6.8%). Iron deficiency was the most common cause of anaemia and was established by laboratory studies in 203 (68%) of 298 anaemic subjects who were followed up. Iron deficiency was an important aetiological factor in 91 (93%) of 98 subjects with moderate or severe anaemia. Folate deficiency was found, usually in combination with iron deficiency, in 44 or 141 anaemic indian adults were followed up. Folate deficiency was uncommon in Fijian adults and among children of either race. Two cases of nutritional vitamin B12 deficiency, one case of pernicious anaemia, 6 cases of heterozygous thalassaemia and one case of heterozygous haemoglobin E were found among the anaemic Indian subjects. No cases of vitamin B12 deficiency anaemia, thalassaemia or haemoglobinopathy were detected among the Fijians. In 5 Indians and 7 Fijians the anaemia was associated with an underlying chronic disorder. This study emphasizes that in Fiji, as in other developing countries, nutritional anaemia is prevalent among asymptomatic subjects. Iron deficiency is by far the most common cause.

Adolescent↗
PubMed1973

Inhibition by thyrocalcitonin of estrogen-induced bone resorption in the mouse pubic symphysis.

A specific local erosion of the medial edges of the pubic bones is induced by administration of estradiol cyclopentylpropionate (ECP) to thyroparathyroidectomized mice. This paper presents both histochemical and biochemical evidence that porcine thyrocalcitonin (TCT) inhibits this estrogen-mediated resorption of the pubic symphysis. A marked increase in osteoclasts with a resultant increase in demonstrable sites of acid phosphatase (AcP) activity was observed in serial sections of resorbing pubic symphyses from ECP-treated animals. Bioassay of excised pubic symphyses revealed a concomitant increase in AcP activity. When mice were treated with TCT in combination with ECP, a marked decrease in osteoclasts with a resultant decrease in demonstrable sites of AcP activity and inhibition of the resorption process occurred. The mouse pubic symphysis thus appears to offer a model for exploring cellular mechanisms by which TCT regulates bone metabolism.

Acid Phosphatase↗
PubMedDate not supplied

Gender differences in glycosylated hemoglobin levels in seasonal affective disorder patients and controls.

Seasonal affective disorder (SAD) has been shown to manifest different symptoms in female and male patients. Specifically, women with SAD have been shown to have greater increases in overeating, weight gain, and increased sleep as compared with their male counterparts. Given these dietary changes, we predicted that female SAD patients would exhibit increased glycosylated hemoglobin (HbA1) levels, indicative of chronically elevated glucose levels. Twenty-two patients (15 women and seven men) and matched controls were enrolled during the winter season and tested for HbA1 levels. A three-way analysis of variance (ANOVA; gender x group x season) was insignificant and the result was a negative study. After the initial hypothesis was rejected, we undertook a post-hoc analysis of the data, from which emerged that in winter, women patients had higher HbA1 levels as compared with matched controls. As our original hypothesis was rejected, we cannot accept the results of the post-hoc study. However, numerous other studies have demonstrated that female and male SAD patients differ in their pathophysiology, and are suggestive that in future analyses ought to consider analyzing subjects separately across gender.

Adult↗
PubMedDate not supplied

Serological complications of a major ABO incompatible bone marrow transplantation in a Polynesian with aplastic anemia.

A 24-year-old, blood-group O Polynesian woman with multiple red blood cell antibodies received a group A, HLA-compatible, sex-matched bone marrow transplantation as treatment for severe aplastic anemia. High retransplantation titers of ABO isohemagglutinins were successfully reduced by repeated plasmaphereses. Despite gross in vitro incompatibility in the routine crossmatch, technetium-labelled red blood cell survival studies performed immediately prior to transplantation predicted that a small proportion of the donor erythrocytes would neutralize residual postplasmapheresis isoantibody. Donor marrow was subsequently infused without significant hemolysis. Although anti-A titers were low immediately posttransplantation, these rose progressively, approaching pretransplantation levels at the time of documented marrow engraftment at day 18. One week later the bone marrow graft was rejected. Retransplantation was successfully performed using marrow from an ABO compatible, sex-mismatched sibling donor. Radioisotopic studies were helpful in evaluating donor-recipient red blood cell incompatibility during the ABO incompatible transplantation, and again at retransplantation in the presence of circulating isoantibody to donor red blood cells. High levels of ABO isoagglutinins prior to plasmapheresis and rapidly rising titers posttransplantation may have predicted bone marrow graft rejection in this patient.

ABO Blood-Group System↗