The response of gastric secretion and serum gastrin to an insulin infusion test in patients with duodenal ulcer

The intravenous infusion of insulin 0.04 U/kg-hr for 2-1/2 hours was performed in 26 patients with chronic duodenal ulcer. In 15 patients this infusion test was compared with the standard test of a single intravenous injection of insulin 0.2 U/kg. The mean lowest blood glucose level in the infusion group (25.1 mg/100 ml) was significantly higher than in the standard test (17.4 mg/100 ml), and the interval from injection to acid stimulation about twice as long (75versus 45 minutes). The peak acid output and mean rise in acidity were comparable in the two procedures. Serum gastrin responded reciprocally to insulin-induced hypoglycemia with a significant inverse correlation between blood glucose and gastrin. In 13 patients tested after vagotomy, there was no significant difference in the rise in acidities in the two groups, and the Hollander status was the same in all but one patient. The mean basal, peak, and absolute rise of serum gastrin in unoperated patients and patients with incomplete vagotomy were almost identical. In patients with complete vagotomy there was no significant rise in serum gastrin after insulin infusion. Unpleasant side effects as assessed by an independent observer were fewer and less severe in patients undergoing infusion tests than in the standard test. The insulin infusion test is recommended as a safer and more acceptable test than the standard insulin test since it avoids severe hypoglycemia and has milder side effects yet achieves comparable acidity and acid outputs. Measurements of serum gastrin after either insulin test provide no additional information helpful in the assessment of the completeness of vagotomy.     

Ophthalmoplegia With Migraine in Adults: Is It Ophthalmoplegic Migraine?

Objective.— Ophthalmoplegic migraine (OM) is a rare disorder characterized by recurrent oculomotor nerve palsy in children, following migraine headaches. We report 62 adults, seen consecutively, who developed acute ophthalmoplegia with severe attacks of migraine over a 10-year (1996-2005) period. An overwhelming majority of these patients had an antecedent worsening in severity of migraine headaches, before the ophthalmoplegic attack.
Methods.— Sixty-two patients, aged 15-68 years, with an acute attack of OM underwent detailed clinical, biochemical, and neuroradiological evaluation.
Results.— There were 62 patients with 86 attacks of OM. Whereas 48 patients had a single attack, 14 had 2 or more attacks, fulfilling the International Headache Society criteria for probable and definite OM, respectively. At presentation, isolated abducens, oculomotor, and trochlear nerve involvements were seen in 35 (56.5%), 21 (33.9%), and 5 (8.1%) patients, respectively. One patient had simultaneous involvement of 3rd and 6th nerves. Fifty-one (82.3%) patients exhibited an antecedent worsening in severity of migraine, before developing ophthalmoplegia during (59/95.2%) or within 24 hours (3/4.8%) of a severe migraine attack, respectively. Detailed biochemistry and cranial neuroimaging were normal. No case had any nerve enhancement. Use of steroids hastened recovery ( P  < .05).
Conclusion.— We conclude: (1) OM in adults is characterized by single attacks of ophthalmoplegia in a great majority of patients; and (2) 6th nerve involvement occurs commonly. Our results indicate that moving OM to the chapter on cranial neuralgias in the second edition of the International Headache Classification may be premature, since nerve palsy occurred during a severe migraine attack in all patients.     

Blood pressure response to the first dose of angiotensin-converting enzyme inhibitors in congestive heart failure

Angiotensin-converting enzyme (ACE) inhibitors improve survival in heart failure and delay progression to clinical heart failure in patients with left ventricular dysfunction after myocardial infarction. Increasing numbers of older patients are being considered for such treatment. However, there are reports of excessive and prolonged decreases in blood pressure (BP) after the first dose of some ACE inhibitors. We have studied the hemodynamics, pharmacokinetics, and neurohumoral responses to the first dose of oral captopril 6.25 mg, enalapril 2.5 mg, perindopril 2.0 mg, intravenous enalaprilat 1.5 mg, and perindoprilat 1.0 mg, compared with oral or intravenous placebo in 6 parallel groups of 12 elderly patients each with moderate-to-severe (New York Heart Association classes II-IV) heart failure. Oral dosing with active drugs led to different temporal responses. After captopril, there was an early short-lived decrease in BP. Enalapril led to a later long-lasting decrease, but perindopril was not different from placebo. Intravenous enalaprilat and intravenous perindoprilat each lowered BP to a similar extent. The doses of drugs used appeared to be comparable because plasma ACE inhibition was similar following perindopril or enalapril and also comparing perindoprilat and enalaprilat. These studies indicate that oral ACE inhibitors have different profiles of acute BP changes after the first dose. The explanation is not clear, but could include physicochemical differences in the interaction between prodrug ester and diacid metabolites leading to differences in tissue distribution and local enzyme inhibition.     

Mouse strain variability in the expression of the hematopoietic stem cell antigen Ly-6A/E by bone marrow cells

The cell surface molecule Ly-6A/E provides a convenient marker for primitive stem cells in the hematopoietic tissues of both fetal and adult mice. However, previous studies have shown that Ly-6A/E expression by lymphocytes is variable depending on the haplotype of the Ly-6 locus. Therefore, strain-specific variation in Ly-6A/E expression by bone marrow (BM) cells was investigated. The results show that Ly-6a mice have, on average, 50% of the number of BM cells expressing Ly-6A/E relative to that for Ly-6b mice. Furthermore, among the 5% of BM cells that do not express antigens characteristic of mature T, B, myeloid, or erythroid lineages, which include the primitive hematopoietic stem cell compartment, Ly-6a mice have, on average, more than fivefold fewer Ly- 6A/E+ cells relative to that for Ly-6b mice. Isolation of Ly-6A/E- and Ly-6A/E+ cells from mice of both haplotypes showed that, whereas 99% of the marrow repopulating activity (MRA) of C57BL/Ka (Ly-6b) mice could be recovered in the Ly-6A/E+ fraction, only about 25% of the MRA of BALB/c (Ly-6a) was recoverable in the same population. On a per-cell basis, the Ly-6A/E+ cells that were isolated from BALB/c mice were essentially equivalent in MRA to those isolated from C57BL/Ka mice. Thus, whereas a large percentage of the hematopoietic stem cells of Ly- 6a mice do not express the Ly-6A/E molecule, the antigen may be used to isolate a subset of stem cells from these mice. These results show that hematopoietic stem cell phenotype can vary between mouse strains and imply that caution should be exercised in the identification of human stem cell antigens such as CD34, because a similar variability may occur between individual humans. To further explore the influence of Ly- 6 haplotype on Ly-6A/E expression by specific cell subsets, lymph-node lymphocytes from a panel of mouse strains were analyzed by multiparameter flow cytometry for correlated expression of Ly-6A/E, CD4, and CD8. All Ly-6a strains examined had less than 20% Ly-6A/E+ cells, and those cells were predominantly CD8+ T lymphocytes. In contrast, the Ly-6b strains had greater than 30% Ly-6A/E+ cells, and those cells included CD4+, CD8+, and B lymphocytes.     

Transfected leukocyte integrin CD11b/CD18 (Mac-1) mediates phorbol ester-activated, homotypic cell:cell adherence in the K562 cell line

The CD11b/CD18 leukocyte integrin molecule mediates diverse neutrophil adherence-related functions, including cell:cell and cell:extracellular matrix attachments. To study the individual role of this leukocyte integrin in cell adherence in hematopoietic cells, we expressed the CD11b/CD18 complex on the surface of K562 cells, a cell line derived from an individual with chronic myelogenous leukemia in blast crisis. We used an amphotrophic retroviral vector designated LCD18SN, harboring the complete coding sequence for the CD18 subunit, to transfer the CD18 cDNA into K562 cells and select stable cell lines. The CD11b subunit in the expression plasmid pREP4 was transfected into these K562/CD18 cells by electroporation and stable cell clones were selected. These K562 cells possessed RNA and intracellular protein for each subunit, and they expressed the CD11b/CD18 heterodimer on the cell surface. When CD11b/CD18 expressing K562 cells were stimulated with phorbol myristate acetate (50 ng/mL) for 24 to 48 hours, these K562 cells formed dense cell:cell aggregates. This homotypic aggregation required both activation of the CD11b/CD18 complex and the induction of the counter- receptor for CD11b/CD18 on the conjugate cell. This cell line will (1) enable the structure-function relationships between cell activation and homotypic adherence to be assessed, (2) provide the opportunity to identify accessory molecules required for activation of the CD11b/CD18 complex, and (3) facilitate the identification of novel ligands for the CD11b/CD18 complex.     

Expression of a fibrinogen fusion peptide in Escherichia coli: a model thrombin substrate for structure/function analysis

The initial event in fibrin clot formation is the thrombin-catalyzed cleavage of the A alpha chain of human fibrinogen. Most of the information required for thrombin recognition and cleavage of the A alpha chain lies in the amino terminal 51 residue CNBr fragment. By selective modification of residues in this region, we probed the features that participate in thrombin interactions. We constructed a vector which expressed a tripartite protein (tribrid) consisting of amino acids 1 to 50 of the A alpha chain followed by 60 amino acids of chicken collagen and the beta-galactosidase protein from Escherichia coli. Cell lysates run on NaDodSO4-polyacrylamide gels contained the predicted band of molecular weight (mol wt) 125,000. The tribrid reacted with a monoclonal antibody, Mab-Y18, which recognizes the amino terminus of the A alpha chain. When cell lysates were incubated with thrombin, FPA was released. By including one heterogeneous oligonucleotide in the construction, we generated plasmids that encoded three specific amino acid substitutions. Surprisingly, changing Gly14 to Val did not alter thrombin cleavage, although recognition by Mab-Y18 was lost. Substitution of lie for Arg23 did not alter either thrombin cleavage or monoclonal recognition. Substitution of Leu for Arg 16 altered thrombin cleavage; unexpectedly, recognition by Mab-Y18 was not changed.     

Molecular genetic demonstration of the diverse evolution of Richter's syndrome (chronic lymphocytic leukemia and subsequent large cell lymphoma)

Paired samples of chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) and the subsequent diffuse large cell lymphoma (DLL) of six cases of Richter's syndrome were investigated to establish the clonal relationship between the CLL/SLL and the DLL components and to define the oncogene and/or tumor-suppressor gene alterations involved in the morphologic transformation of CLL/SLL. Southern blot hybridization analysis showed identical clonal immunoglobulin (Ig) gene-rearrangement patterns in the CLL/SLL and DLL components in four cases and different Ig gene-rearrangement patterns in two cases. Polymerase chain reaction (PCR) amplification, cloning, and DNA sequencing of complementary determinant region 3 (CDR3) of the Ig-heavy chain gene of one of the two cases in which the Ig gene- rearrangement patterns were different showed nonidentical sequences in the CLL/SLL and DLL components. In the other case, monomorphic Epstein- Barr virus (EBV) genome integration was detected in the DLL but not in the CLL, suggesting that the CLL and DLL components in this case of Richter's syndrome also represent unrelated clones. Single-strand conformation polymorphism (SSCP) analysis and sequencing of exons 5 through 9 of the p53 tumor-suppressor gene showed a mutation in codon 176 of the DLL but not in the CLL/SLL component in one case where the CLL/SLL and DLL represented different clones. The p53 mutation probably played a role in the development of the lymphoma rather than morphologic transformation of the CLL/SLL in this case. SSCP analysis and sequencing also showed identical mutations in codon 282 in both the CLL/SLL and DLL components in a case where the CLL and DLL represented identical clones. Thus, this p53 gene mutation was present both before and after morphologic transformation, and therefore, probably did not play a primary role in this process. Southern blot hybridization analysis failed to show evidence of bcl-1, bcl-2, c-myc proto-oncogene or retinoblastoma (Rb) tumor-suppressor gene rearrangements in these six cases of Richter's syndrome. In conclusion, the original CLL/SLL and the subsequent DLL in Richter's syndrome may or may not be derived from identical clones, and the well-known proto-oncogenes and tumor- suppressor genes do not appear to play an obvious and consistent role in the morphologic transformation of CLL/SLL to DLL.