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Biomedical subjects

H Blacklock

Publications and source records attributed to H Blacklock.

At least 19 recordsLinked to original sources
PubMed1998

D-D dimers: a poor correlate of PPIH and subsequent outcomes.

OBJECTIVES: To ascertain the normal range of D-D dimer levels in pregnancy in our population, and whether dimer levels are of value as a correlate of proteinuric pregnancy-induced hypertension (PPIH) or a predictor of adverse outcome. METHODS: Dimer levels were measured in 44 women diagnosed with PPIH after 32 weeks' gestation and 55 controls recruited before 24 weeks' gestation. RESULTS: Mean dimer levels in the second and third trimester of normal pregnancy were 45 ng/ml (+/- 1 S.D., 15-134) and 85 ng/ml (+/- 1 S.D., 40-180), respectively (P < 0.001). Mean dimer level in PPIH was 148 ng/ml (+/- 1 S.D., 76-292), differing significantly from normal pregnancy by ELISA but not by latex particle assay. No correlation was found between dimer levels and adverse outcome, nor between dimer levels and any one particular adverse outcome. CONCLUSION: These results suggest that dimer levels are not a useful correlate of PPIH, nor do they have a useful predictive value for adverse outcome in PPIH.

Female↗
PubMed1998

Long-term pamidronate treatment of advanced multiple myeloma patients reduces skeletal events. Myeloma Aredia Study Group.

PURPOSE: To determine the efficacy and safety of 21 monthly cycles of pamidronate therapy in patients with advanced multiple myeloma. PATIENTS AND METHODS: Patients with stage III myeloma and at least one lytic lesion received either placebo or pamidronate 90 mg intravenously administered as a 4-hour infusion monthly for 21 cycles. At study entry, the patients were stratified according to whether they were to receive first-line (stratum 1) or second-line (stratum 2) antimyeloma chemotherapy. Skeletal events (pathologic fracture, radiation or surgery to bone, and spinal cord compression) and hypercalcemia were assessed monthly. RESULTS: The results of the first nine previously reported cycles are extended to 21 cycles. Of the 392 randomized patients, efficacy could be evaluated in 198 who received pamidronate and 179 who received placebo. After 21 cycles, the proportion of patients who developed any skeletal event was lower in the pamidronate-group (P = .015). The mean number of skeletal events per year was less in the pamidronate-group (1.3) than in placebo-treated patients (2.2; P = .008). Although survival was not different between the pamidronate-treated group and placebo patients overall, stratum 2 patients who received pamidronate lived longer than those who received placebo (14 v 21 months, P = .041). Pamidronate was safe and well tolerated during the 21 cycles of therapy. CONCLUSION: Long-term monthly infusions of pamidronate as an adjunct to chemotherapy are superior to chemotherapy alone in reducing skeletal events in stage III multiple myeloma patients, and may improve the survival of patients on salvage therapy.

Diphosphonates↗
PubMed1991

Four different mutations in codon 28 of alpha spectrin are associated with structurally and functionally abnormal spectrin alpha I/74 in hereditary elliptocytosis.

Hereditary elliptocytosis (HE) Sp alpha I/74 is a disorder associated with defective spectrin (Sp) heterodimer self-association and an abnormal tryptic cleavage of the 80-kD alpha I domain of Sp resulting in increased amounts of a 74-kD peptide. The molecular basis of this disorder is heterogeneous and mutations in codons 28, 46, 48, and 49 (codons 22, 40, 42, and 43 in the previous nomenclature which did not include the six NH2-terminal amino acids) have been reported. In this study we present data on seven unrelated HE Sp alpha I/74 kindred from diverse racial backgrounds in whom we identified four different mutations all occurring in exon 2 of alpha Sp at codon 28. Utilizing the polymerase chain reaction we established a CGT----CTT; Arg----Leu 28 mutation in one kindred of Arab/Druze origin. In two unrelated white kindred of English/European origin the substitution is CGT----AGT; Arg----Ser 28 and in two apparently unrelated white kindred from New Zealand, the mutation is CGT----TGT; Arg----Cys 28. Finally, in one American black kindred and in a black kindred from Ghana the mutation involves CGT----CAT; Arg----His 28. Allele specific oligonucleotide hybridization confirmed that the probands are heterozygous for the respective mutant alleles. All four point mutations abolished an Aha II restriction enzyme site which allowed verification of linkage of the mutation with HE Sp alpha I/74. Our results imply that codon 28 of alpha Sp is a "hot spot" for mutations and also indicate that Arg 28 is critical for the conformational stability and functional self association of Sp heterodimers.

Base Sequence↗
PubMed1988

A randomized trial of empirical antibiotic therapy with one of four beta-lactam antibiotics in combination with netilmicin in febrile neutropenic patients.

Over a two year period 174 evaluable episodes of fever in neutropenic patients were treated in a randomized study comparing four beta-lactam antibiotics, each given in combination with netilmicin. Exclusions included episodes due to viral or fungal infection, and trial violations. Most patients were receiving treatment for leukaemia, including 18% undergoing bone marrow transplantation. The overall response rate (EORTC criteria) was 66%, ranging from 56% for cefoperazone to 76% for mezlocillin. Microbial documentation was obtained in 31% of episodes; Gram-positive isolates were most frequent but Pseudomonas aeruginosa was found in 18 patients. In patients with microbiologically documented infection 70% improved, overall--from 40% with cefoperazone to 80% with piperacillin (P less than 0.05). Nephrotoxicity was seen in 6.7% and was associated with severe documented sepsis. Hypokalaemia was seen in 29% and was most marked in patients receiving ticarcillin. Rashes occurred in 6.6% overall, with no difference between the groups. Ototoxicity, shown by serial audiograms, was seen in 4.7% of patients. No evidence of vestibular dysfunction was seen in 62 patients studied. Of thirteen deaths due to the primary infection, seven were caused by Ps. aeruginosa and five by fungi.

Agranulocytosis↗
PubMed1987

The effect of total body irradiation and bone marrow transplantation during childhood and adolescence on growth and endocrine function.

Seventeen children (11 M, 6 F) with acute leukaemia and myeloproliferative disorders were investigated for growth and endocrine dysfunction. All had undergone bone marrow transplantation prepared with cyclophosphamide and single fraction total body irradiation (900-1000 cGy) between 1.5 and 3.8 (mean 2.2) years previously. The majority of children exhibited growth failure, which was of multiple aetiology. Ten patients, of whom eight had had previous prophylactic cranial irradiation, had evidence of growth hormone deficiency based on the reduced growth hormone response to insulin induced hypoglycaemia. Three patients had evidence of hypothalamic damage as shown by their growth hormone response to 200 micrograms GHRH (1-29) NH2 intravenously. Gonadal failure was common, assessed clinically, and biochemically by basal gonadotrophin and sex steroid concentrations. All four girls of adolescent age (10.6-14.1 years) had ovarian failure requiring sex steroid replacement. Of the eight boys of adolescent age (12.3-18.3 years), two had testicular failure requiring sex steroid supplements. Both of these had had previous testicular irradiation. Five others had compensated gonadal failure, and one had normal Leydig cell function. Abnormalities of the TSH response to TRH occurred in 10 patients but only three had overt hypothyroidism. Unlike growth hormone deficiency, gonadal and thyroid dysfunction showed no correlation with previous cranial radiotherapy.

Adolescent↗
PubMed1986

Bone-marrow transplantation has a limited role in prolonging second marrow remission in childhood lymphoblastic leukaemia.

Fifty-three children with acute lymphoblastic leukaemia whose first complete remission ended in bone-marrow relapse received similar reinduction and consolidation therapy. Thirteen had an HLA-compatible sibling donor and were eligible to receive a bone-marrow transplant (BMT); five survive, all off treatment in continuing remission. Forty had no donor and received further chemotherapy; sixteen survive, twelve in remission and six off treatment. After 1-5.5 years' follow-up from relapse, there is no significant difference in survival between the groups. The major obstacle to success is marrow relapse which occurred in two eligible patients before BMT could be carried out. The lengths of first and second remissions in both groups were significantly correlated. Morbidity in survivors was substantial. The scope of BMT as retrieval therapy for ALL is limited by the instability of second remissions; this difficulty will not be overcome by increasing the number of potential donors or the use of autologous marrow.

Adolescent↗
PubMed1986

Salivary amylase and pancreatic enzymes in serum after total body irradiation.

Amylase increases in serum after total body irradiation (TBI). To investigate whether this increase is ascribable to pancreatic or salivary amylase, or both, we measured the post-irradiation activity concentration of the three major pancreatic enzymes (trypsin, amylase, and lipase) and of salivary-type amylase in serum from six leukemic patients given TBI before bone-marrow transplantation. Salivary amylase increased by as much as 50-fold after TBI, peaking on the first day after the irradiation. The increase was associated with the development of clinical parotitis. Pancreatic trypsin, total amylase, and lipase increased inconsistently and to a much smaller degree. There were no associated clinical features of pancreatitis. Our data show that, at the dose of radiation given to our patients, there is no danger of pancreatitis as a complication, but parotitis is a consistent development after TBI.

Amylases↗
PubMed1983

T cell regeneration after allogeneic bone marrow transplantation.

Various T cell subsets were characterized by double immunofluorescent staining using monoclonal antibodies (MoAb) in blood, bone marrow (BM) and tissues of 29 patients after allogeneic BM transplantation (BMT). In an attempt to prevent graft versus host disease (GvHD), 15 patients received cyclosporin A (Cy A). In the remaining 14 patients the BM was pre-incubated with a MoAb, OKT3. The regeneration of T4+ subset was delayed and the level of T8+ cells was abnormally high even 1 year after engraftment. This did not have any predictive value for the appearance of complications such as GvHD or severe viral infections. The number of T8+ cells was lower in the group of patients who received Cy A than in the OKT3 group (0.7 +/- 0.2 vs 1.5 +/- 0.3 X 10(9)/1 at day 90). In contrast to normal individuals, the T4/T8 ratio in both blood and regenerating BM of BMT patients was less than 1. A sizeable subset of circulating T cells expressed the phenotype T8+, T10+, HNK-1+, DR+. Circulating cells of this phenotype were transiently very high (up to 50%) in patients with active GvHD or suffering from severe viral infection. This subpopulation of lymphocytes was not found in the epidermal infiltrate that accompanied GvHD where the predominant phenotype was T8+, T1-, T10-, HNK-1-, DR-. We conclude therefore that after BMT the number and phenotype of circulating T cells reflects the T cell distribution seen in the regenerating BM.

Adolescent↗
PubMed1982

Elimination of T-lymphocytes from human bone marrow with monoclonal T-antibodies and cytolytic complement.

Complement-mediated cytolysis has been used to remove T-lymphocytes from suspensions of human peripheral blood and bone marrow. Selective T-cell removal was investigated by three monoclonal antibodies. OKT3, MBG6 and OKT11A. All three removed greater than 90% of T-cells but combinations were necessary to kill greater than 99% of T-cells in vitro. The macrophage-granulocyte and erythroid colony forming cells of the bone marrow were spared. The method can be applied on bulk BM samples during clinical BM transplantation and will be useful to establish whether the virtually complete removal of T-lymphocytes totally prevents transplant associated graft-versus-host disease in man.

Antibodies, Monoclonal↗
PubMed1981

Therapeutic selectivity of and predication of response to 2'-deoxycoformycin in acute leukaemia.

Seventeen patients with acute leukaemia refractory to conventional chemotherapeutic agents were treated with the adenosine deaminase inhibitor, 2'-deoxycoformycin (dCF). Of the twelve patients with acute lymphoblastic leukaemia of the thymic phenotype (Thy-ALL), seven went into complete remission after one or two courses of therapy. Two other (Thy-ALL) patients showed good partial response, and three were resistant to dCF. The five patients with acute leukaemia of other phenotypes had progression of disease despite treatment with dCF. Response to dCF can be predicted from the pattern of change in cellular nucleotide levels in blood and/or bone marrow blasts which have been treated in vitro with dCF and deoxyadenosine. The main adverse effects of dCF therapy were renal and liver dysfunction, conjunctivitis, and haemolysis.

Acute Disease↗