Spontaneous regeneration of free muscarinic receptor after alkylation by BM 123. II. Recovery in broken cell preparations

Muscarinic receptors from rat cerebral cortex were found to recover from alkylation by the specific ligand N-[-(2-chloroethyl-methylamino)-2-butynyl]-2-pyrrolidone (BM 123) without the benefit of cellular integrity, i.e., in washed membranes incubated at 37 degrees C for relatively long times (days). Unalkylated receptor number increased in alkylated preparations whether viewed as femtomoles per milligram of protein or as a percentage of the atropine-protected control. The rate of recovery was independent of pH over the range 6 to 9 and it was slowed but not eliminated by incubation at 4 degrees C. Muscarinic receptor recovery from BM 123 was linearly dependent on the concentration of alkylated receptors, indicating first-order kinetics and yielding a rate constant 0.026/hr. Of the other chloroethylamines examined for evidence of in vitro muscarinic receptor recovery from alkylation, only one, phenoxybenzamine, exhibited irreversible receptor blockade under these conditions. Each of the others showed different rates for regeneration of free receptors.     

Anterior approach to celiac plexus block during interventional biliary procedures

A fluoroscopically guided anterior approach to celiac plexus block was developed that can be performed on the supine patient during a percutaneous biliary procedure. Unlike posterior blocks, anterior blocks can be performed at any time during the procedure and thus can be reserved for the few patients whose pain does not respond to intravenously administered narcotics. Anterior blocks were performed 18 times in 14 patients; satisfactory visceral anesthesia was achieved in ten of the 18 procedures.     

ABDOMINAL SYMPTOMS,HYPERCALCAEMIA AND APATHETIC HYPERTHYROIDISM: TREATMENT WITH PAMIDRONATE

SUMMARY A 24-year-old man with anorexia, repeated bouts of vomiting, and wasting was found to have florid thyrotoxicosis and hypercalcaemia. Pamidronate promptly reduced the serum calcium concentration to normal, and simultaneously abated the abdominal symptoms, which did not recur in spite of continuing severe hyperthyroidism, which was eventually controlled by radioactive iodine ablation of thyroid activity.     

Predictive value of umbilical artery pH in preterm infants

Compared with term infants, little information is available about the usefulness of the umbilical artery pH in relation to outcome in extremely preterm infants. This prospective study evaluates the relation between umbilical artery pH (UapH), Apgar scores, perinatal events, and outcome in infants born at less than 32 weeks' gestation. Six hundred and twenty three infants of < 32 weeks' gestation were studied. The median UapH was 7.25, with a range of 6.78-7.49. A low UapH was significantly associated with male sex, hyaline membrane disease, grade 3 or 4 intraventricular haemorrhage, and neonatal death. It was also associated with lower birth weight and lower birthweight centile. The relations between the UapH and outcomes of neonatal death, cerebral palsy, and developmental quotient at 1 year, and other perinatal risk factors were then examined using multiple logistic regression. After adjusting for other risk factors, UapH was not significantly associated with any outcome. In contrast, a low one minute Apgar (< 4) remained a significant risk factor, with odds ratios of 2.7 (95% confidence interval (CI) 1.5 to 5.2) for neonatal death and 3.8 (95% CI 1.4 to 10.4) for cerebral palsy.     

Analysis of proto-oncogenes in acute myeloid leukemia: loss of heterozygosity for the Ha-ras gene

At least 13 of 34 patients with acute myeloid leukemia (AML) of varying FAB types were heterozygous for a BamHI restriction fragment length polymorphism (RFLP) of the Ha-ras gene on chromosome 11. In 4 of these 13 patients, one allele of the Ha-ras gene was deleted. Two of these cases had an informative heterozygosity for an RFLP on the long arm of chromosome 11. Analysis of these cases indicated that loss of genes from chromosome 11 was restricted to the short arm. In three cases with loss of one Ha-ras gene, the remaining gene had no mutations in critical areas of exons 1 and 2. With the exception of one AML case with amplification of MYC, no gross structural abnormalities in 12 other oncogenes were detected.     

The British form of hereditary persistence of fetal hemoglobin results from a single base mutation adjacent to an S1 hypersensitive site 5' to the A gamma globin gene

The G gamma and A gamma genes of an individual homozygous for the British form of A gamma nondeletion hereditary persistence of fetal hemoglobin have been cloned and partially sequenced. The G gamma gene was normal, but the A gamma gene was found to have a single base change (T----C) at -198 bp relative to the cap site. Supercoiled plasmids containing normal gamma-genes or the mutant A gamma-gene displayed an S1-hypersensitive site immediately 5' to the base change.     

TCA: a polymorphic genetic marker in leukemias and melanoma cell lines

TCA (T Cell system A) is a di-allelic system of HLA-like antigens encoded by genes located about 15 cM telomeric to HLA-A. In normal individuals, TCA antigens are only expressed on a subpopulation of T cells, the TG lymphocytes. We now report on the expression of TCA on leukemias and other malignancies. An increased proportion of cells carrying the TCA phenotype was encountered in testing peripheral blood lymphocytes from patients with acute lymphoblastic T-cell leukemia (T- ALL), acute myeloid leukemia (AML), and chronic myeloid leukemia (CML). In contrast, patients with B-cell malignancies such as chronic lymphatic leukemia (CLL) and hairy cell leukemia (HCL) or non-T/non-B common acute lymphoblastic leukemia (common ALL) had normal proportions of TCA-positive lymphocytes. Quantitatively different levels of TCA expression are found on some melanoma cell lines and others are TCA negative. These variations are independent of the expression of HLA Class I antigens by the same cells. The expression of TCA antigens by malignant nonlymphoid cells suggests that this system may code for differentiation markers, important in the biology of neoplastic transformation.     

Molecular analysis of T-cell receptor repertoire in bone marrow transplant recipients: evidence for oligoclonal T-cell expansion in graft-versus-host disease lesions

We have analyzed the T-cell receptor (TCR) V beta repertoire using polymerase chain reaction (PCR) in a cohort of eight patients receiving allogeneic bone marrow transplantation (BMT) from related and unrelated donors at the City of Hope. Results of PCR studies from graft-versus- host disease (GVHD) skin lesions show a bias in the usage of TCR V beta families, whereas examination of peripheral blood (PB) withdrawn at the same time did not reveal a similar phenomenon. In one such family, TCR V beta 2 is predominantly expressed in 7 of 7 biopsy specimens examined. V beta 2 TCR expression from these patients was analyzed more extensively using a combination of individual TCR gene cloning, followed by sequence analysis. We found evidence of oligoclonal expansion of single V beta 2-bearing TCRs in GVHD lesions, and in the PB of some patients after diagnosis of GVHD. In contrast, GVHD-negative biopsy samples showed no evidence for clonotypic TCR amplification. Sequence-specific TCR CDR3 region probes were derived from analysis of the predominant expressed TCR in GVHD lesions, and used to probe Southern blots of amplified V beta 2 TCR mRNA from PB and tissue from BMT recipients and their respective donors. In most cases the probes are highly specific in detecting TCR expression from GVHD lesions alone, although in several instances expression could be detected in PB after GVHD diagnosis. These data provide supporting evidence for the hypothesis that acute GVHD is associated with expansion of T-cell clones expressing antigen-specific TCRs that may contribute to the disease pathology.