Search PubMed⌕ Search

Biomedical subjects

A Burnett

Publications and source records attributed to A Burnett.

17 recordsLinked to original sources
PubMed1992

Effect of stage of lactation and milk accumulation on mammary cell differentiation in lactating bats.

Mammary cell differentiation was measured in lactating pipistrelle bats (Pipistrellus pipistrellus) by assay of key enzyme activities, and by determination of protein and lactose synthesis rates in short-term tissue cultures. By these criteria, mammary cell differentiation did not change significantly with stage of lactation, but depended on the extent to which the gland was filled with milk. Key enzyme activities and in vitro synthesis rates were significantly higher in glands suckled immediately before tissue collection, compared with contralateral glands that were engorged with milk. This indicates that mammary cell differentiation in the lactating bat is regulated locally within each gland by a mechanism sensitive to milk accumulation, to the extent that, unlike other species, this obscures any underlying effect of stage of lactation.

Animals↗
PubMed1992

Spinal abnormalities in young fast bowlers.

The action of fast bowling in the game of cricket is known to cause injuries to the lumbar spine. We studied a group of 16- to 18-year-old fast bowlers, selected for special training in Western Australia. All 24 had MR scans of the spine, 22 had radiographs and CT scans; in 20 the bowling technique was analysed biomechanically. There was a high incidence of back pain and this was always associated with a radiological abnormality. Pars interarticularis defects were diagnosed in 54% and intervertebral disc degeneration in 63%. Bowling actions which involved counter-rotation were associated with a higher incidence of both injuries.

Adolescent↗
PubMed1991

Characterization of descending modulation of nociception from the A5 cell group.

The present study examined the role of the A5 catecholamine-containing cell group in descending modulation of the nociceptive tail-flick (TF) reflex and regulation of blood pressure and heart rate in rats lightly anesthetized with pentobarbital. Systematic mapping studies throughout the A5 cell group, rostral to caudal, showed that electrical stimulation in and near the A5 cell group at intensities as low as 25 microA was sufficient to inhibit the tail-flick (TF) reflex without producing a significant pressor response. Microinjections of glutamate into the same sites to selectively activate cell bodies also produced inhibition of the TF reflex and were accompanied by significant decreases in blood pressure (mean, -23 +/- 4.7 mmHg, n = 21) and non-significant decreases in heart rate (-7.6 +/- 11 bpm). Intrathecal administration of the receptor antagonists phentolamine, yohimbine, prazosin, methysergide, naloxone or atropine revealed that descending inhibition from the A5 cell group produced by electrical stimulation is mediated in part by spinal opioid and alpha-adrenoceptors. Increases in stimulation thresholds in the A5 cell group for inhibition of the TF reflex of 28.3 and 24.1% were produced by intrathecal pretreatment with phentolamine and naloxone, respectively. None of the other receptor antagonists produced significant increases in stimulation thresholds in the A5 cell group for inhibition of the TF reflex. Resting blood pressure and heart rate were not affected by the receptor antagonists.

Animals↗
PubMed1991

Autologous bone marrow transplantation for acute myeloblastic leukemia in Europe: further evidence of the role of marrow purging by mafosfamide. European Co-operative Group for Bone Marrow Transplantation (EBMT).

Fifty-nine European teams have reported 919 autografts for the consolidation of acute myelocytic leukemia (AML) up to December 31, 1989. The distribution for autologous bone marrow transplantation (ABMT) was 671 in first complete remission (CR1) and 196 in CR2. Pretransplantation regimes were: total-body irradiation (TBI), 456; busulfan plus cyclophosphamide (BU-CY) 174; marrow purging with mafosfamide, 269 (corresponding to 26% of all patients in CR1 and 41% in CR2). Patients autografted in CR1 with no high risk factor (standard risk) had a leukemia-free survival (LFS) and relapse rate at 7 years of 48 +/- 2 and 41 +/- 3%, respectively. Of all the prognostic factors studied, only secondary leukemia was correlated with a poorer LFS (19 +/- 9% at 1 year) and a higher relapse rate (76 +/- 11%) (p less than 0.0001). For patients autografted in CR2, the LFS and relapse rate were 34 +/- 4 and 54 +/- 5%. With the restriction of a shorter follow-up, the results achieved with the BU-CY combinations (LFS and relapse rate at 3 years, CR1 47 +/- 6 and 45 +/- 7%; CR2, 37 +/- 9 and 50 +/- 10%) did not differ from those with TBI or other chemotherapy combinations. LFS and relapse rates were correlated with several pretransplant intervals: in CR1, patients reaching CR more rapidly (less than or equal to 40 days) had a better LFS (53 +/- 3 versus 42 +/- 3%; p = 0.03) and a lower relapse rate (46 +/- 3 versus 57 +/- 3%; p = 0.03). In patients autografted less than 3 months, 3-6 months and more than 6 months after CR, the LFS was 26 +/- 5, 49 +/- 3, and 55 +/- 4%, respectively, and the relapse rates 63 +/- 5, 38 +/- 3, and 36 +/- 4% (p less than 0.0001 for both). In CR2, patients autografted more than 18 months after the initial diagnosis had a better LFS (42 +/- 5 versus 24 +/- 5%; p less than 0.001) and a lower relapse rate (45 +/- 6 versus 65 +/- 6%; p less than 0.001). For those autografted less than 3 months, 3-6 months and more than 6 months after CR, the probability of LFS was 30 +/- 5, 30 +/- 7, and 50 +/- 9% (p = 0.06), respectively and the relapse rates 63 +/- 6, 50 +/- 8, and 36 +/- 8% (p = 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1990

Autologous bone marrow transplantation for acute myelocytic leukemia in first remission: a European survey of the role of marrow purging.

We analyzed data from 263 patients with acute myelocytic leukemia (AML) autografted in first remission (CR) during the period from January, 1982 to January, 1987 at one of 34 centers in the European Bone Marrow Transplant Group. The median age of patients was 30 years (range, 1 to 65). The median interval between achieving CR and autografting was 5 months (range, 1 to 23). Of the 263 patients, 131 patients received cytoreductive regimens that included total body irradiation (TBI); the remainder received various combinations of cytotoxic drugs. Sixty-nine patients received autologous marrow purged in vitro with mafosfamide, and 194 received unpurged marrow. The median follow-up was 28 months (range, 12 to 97). For patients with standard risk AML in CR1 autografted after TBI (n = 107), the leukemia-free survival (LFS) was higher, and the probability of relapse was lower in recipients of purged than of unpurged marrow (63% versus 34%, P = .05 and 23% versus 55%, relative risk 0.34, P = .005, respectively). The superior results of purging were most obvious in patients autografted within 6 months of achieving CR (probability of relapse, 20% versus 61%, P = .01). Patients with longer intervals between CR and autografting had higher LFS and lower probability of relapse than those autografted early in CR (intervals greater than 9 months, 7 to 9 months, 4 to 7 months, and less than or equal to 3 months: LFS = 56%, 40%, 35%, 27%, P = .007, probability of relapse = 25%, 56%, 59%, 67%, P = .005; respectively). We conclude that marrow purging with mafosfamide may be valuable for patients autografted early in first CR.

Adolescent↗
PubMed1988

Patency of femorofemoral venous crossover grafts assessed by duplex scanning and phlebography.

This study was undertaken to determine the accuracy of duplex imaging of femorofemoral venous crossover grafts (Palma-Dale operation) for postthrombotic unilateral occlusion of the iliac vein. Twenty-four patients, 14 men and 10 women with a mean age of 50 years (range 24 to 72 years), were subjected to duplex imaging and phlebography a mean of 5 years after surgery. Scanning was done with patients in an erect position. A graft was reported as patient if it met the following criteria: it could be imaged in continuity, it could be compressed by the scan probe, and blood flow varied with respiration and was augmented by thigh compression on the symptomatic side. Phlebography indicated that 20 grafts were patent and 17 of these were correctly identified with duplex scanning. Three scans were false negative in obese patients in whom the graft could not be imaged. Four grafts, not imaged, were confirmed by phlebography to be occluded. Compared with phlebography, duplex scanning had a sensitivity of 85%, specificity of 100%, and overall accuracy of 88%. Duplex scanning is safe and accurate way to determine patency after femorofemoral venous bypass if the criteria for patency are fulfilled. If not, the true status of the graft must still be established by phlebography.

Adult↗
PubMed1988

Autologous bone marrow transplantation in acute lymphoblastic leukemia--preclinical immunologic studies.

Immunologic aspects of autologous bone marrow transplantation (ABMT), immunodiagnosis, patient monitoring, and the purging of bone marrow have been studied in individual patients. It was demonstrated that the most sensitive method for detecting lymphoid cells which show the phenotypes of ALLs of B or T lineage was double immunofluorescence staining for nuclear terminal transferase (TdT) and B or T lineage antigens. With the help of these sensitive tests in the presence of rabbit complement (C'), MAbs CD10 (RFAL3 of IgM class), CD19 (SB4 of IgM class), and their cocktail were capable of eliminating greater than 3 log blast cells of B lineage ALL in 84%, 75.5%, and 90% of cases, respectively. The same reagents lysed 26.8%, 0%, and 45% of blasts in the presence of human C'. CD7 (RFT2, IgG2) eliminated greater than 3 log T-ALL blast cells in 73% of cases. The proliferative fractions of leukemic blasts were also TdT+ and sensitive to lysis with MAb and C'. On the basis of these observations MABs were selected for purging in 36 patients undergoing ABMT in first remission (10 patients considered to be at a high risk of relapse), second and third remissions (23 and 2 patients), and without entering into remission (1 patient). The efficacy of eliminating the MAb-reactive cells from the bone marrow inoculum was also documented in five patients. By the use of sensitive immunologic assay (TdT/cytoplasmic CD3 double staining) in patients with T-ALL, no residual leukemia (less than 10(-4] could be detected at the time of transplantation. Following an observation period of 5-34 months, 24 of the 36 patients are alive and well with no procedure-related mortality.

Antibodies, Monoclonal↗
PubMed1987

Ultrasound-guided brain abscess aspiration in neonates.

Four cases of brain abscess in neonates are described, diagnosed by ultrasonography and CT. All abscesses were confirmed surgically. One patient was operated on 5 weeks after diagnosis because of initial parental refusal. The etiology in all cases was meningitis superimposed on an hypoxic-ischemic insult. Two cases had a single abscess while the other two had multiple lesions. All cases were operated on with intraoperative ultrasound examination through the fontanelle. The case with delayed aspiration showed complete evolution from localized cerebritis to complete capsule formation with mass effect. One abscess was sterile, and in the others grew Klebsiella pneumoniae and Enterobacter aerogenes. The microorganism initially isolated from the lumbar CSF was also found in the abscess. Even after sterilization of the lumbar CSF, all abscesses were still present. Ultrasound examination and CT are compared.

Brain Abscess↗
PubMed1986

Impaired cell mediated immunity in haemophilia in the absence of infection with human immunodeficiency virus.

The cell mediated immune response was evaluated in vivo in 29 patients with clinically severe haemophilia by means of the dinitrochlorobenzene skin test. All patients had a response below the median normal value, and in 19 the response was on or below the lower limit of the normal range. There was no difference in skin response between patients positive and negative for the human immunodeficiency virus (HIV; formerly known as human T cell lymphotropic virus III or lymphadenopathy associated virus). In the whole group, and in seronegative patients (n = 17), there was an inverse relation between exposure to clotting factor and skin response. In seropositive patients (n = 12) no such association was apparent. This study shows that clotting factor concentrate impairs the cell mediated immune response to a new antigen in the absence of infection with HIV.

Acquired Immunodeficiency Syndrome↗
PubMed1986

A prospective study of the histological changes in the skin in patients receiving bone marrow transplants.

Fourteen patients who received a bone marrow transplant (BMT) as treatment for leukaemia were included in a prospective study of the histological changes in the skin. The aim of this study was to improve the early diagnosis of graft-versus-host disease (GVHD). It was found that the clinically 'normal' pre-transplant skin was in some cases histologically abnormal on H & E examination in patients who were on regular maintenance cytotoxic chemotherapy. These changes were similar to some of the features of GVHD. Immunocytochemistry, although not specific, was found to be helpful in the diagnosis of some cases of GVHD. Suggestive features included a reduction in the numbers of Langerhans cells, an increase in the number of suppressor (OKT8+) cells in the dermal infiltrate and the presence of Ia positivity of the keratinocytes in the epidermis.

Adult↗
PubMed1986

Autologous bone marrow transplantation for acute leukaemia in remission.

Between 1980 and 1985, 175 patients with acute leukaemia in first or subsequent complete remission (CR) were treated by chemotherapy or chemoradiotherapy followed by transfusion of autologous bone marrow cells that had been collected days or months previously. In 85 cases, autologous marrow cells were treated ex vivo with cytotoxic drugs or monoclonal antibodies with the intention of removing residual leukaemic cells. The actuarial relapse-free rate was 52% at 2 years. Of 89 patients autografted for acute non-lymphocytic (myeloid) leukaemia (ANLL), 60 were treated in first remission and 18 in second CR; their relapse-free rates at 2 years were 67% and 41% respectively (P less than 0.001). In contrast, of 77 patients autografted for acute lymphoblastic leukaemia (ALL), 32 were treated in first CR and 28 in second CR and their actuarial relapse free rates at 2 years were 56% and 55% respectively (P = NS). There was no significant difference in leukaemia relapse rates between patients autografted with purged and those autografted with non-purged marrow cells. These preliminary results suggest that autologous bone marrow transplantation may be valuable if offered to patients with ANLL in first CR or to patients with ALL in first or second CR but the need for marrow purging remains uncertain.

Acute Disease↗
PubMed1985

Subacute and chronic bone infections: diagnosis using In-111, Ga-67 and Tc-99m MDP bone scintigraphy, and radiography.

The usefulness of indium-111 white blood cell scintigraphy in the diagnosis of subacute or chronic bone infection was examined in 21 orthopedic patients. In-111 WBC imaging was compared with gallium-67 and technetium-99m methylene diphosphonate skeletal scintigraphy and bone radiography, all studies being performed within 1 week. In-111 WBC scintigraphy showed no definite advantage over Ga-67 scintigraphy in the identification of chronic bone infection. The two tests had the same sensitivity (80%) and similar specificity (In-111 WBC 75%, Ga-67 83%; difference not significant). Bone radiography had a sensitivity of 60% and a specificity of 67%. A negative Tc-99m MDP bone scintigram ruled out infection (sensitivity 100%), but because of low specificity (25%), final evaluation required performance of Ga-67 or In-111 WBC scintigraphy.

Adult↗
PubMed1985

The role of VP-16 in the treatment of small-cell lung cancer: studies of the West of Scotland Lung Cancer Group.

Reviews of published studies indicate that the incorporation of VP-16 (Vepesid) into combination chemotherapy for small-cell lung cancer may improve overall response rates from 50% to between 65% and 80%. In addition, high-dose VP-16 may yield a higher response rate than that obtained with conventional doses. The West of Scotland Lung Cancer Group has therefore conducted studies to examine the effects of VP-16 both in a combination regimen as induction therapy and (together with high-dose cyclophosphamide) as late intensification therapy in high dose, aimed at preventing relapse in responding patients. Response to induction treatment improved with the addition of VP-16, compared to earlier studies carried out by the group, yielding an overall response rate of 80% for patients with limited disease and 62% for those with extensive disease. Although induction therapy comprised only three courses (lasting 9 weeks), the median response duration of 9.5 months for complete responders and the median survival of 14 months for complete responders (limited disease) were in keeping with those obtained using more prolonged induction therapy. The intensification therapy with high-dose cyclophosphamide and high-dose VP-16, however, yielded no improvement in overall survival in those responding patients who received it compared with those who did not. Radiotherapy following late-dose intensification prevented local tumor recurrence but appeared to have no effect on overall survival. Resistance to VP-16 and other drugs is a possible deterrent to successful therapy in small-cell lung cancer, and it is suggested that research focus on a possible role for calcium channel blockers in circumventing drug resistance.

Carcinoma, Small Cell↗