Symptom response to lactose-reduced milk in lactose-intolerant adults

The possible usefulness of low-lactose milk for those lactose-intolerant subjects who develop symptoms from milk consumption was investigated. In the first part of the study, 16 intolerant subjects (blood glucose rise less than 25 mg/100 ml) received low-lactose skim milk containing 15 g lactose (2.5 cups) and 7.5 g lactose (2.5 cups), regular skim milk containing 30 g lactose (2.5 cups), and all three milks plus a small breakfast. The low lactose milks produced significantly fewer symptoms. The food given with the milk had no significant effect on symptomatic response. The second group of 17 subjects received 25 g lactose in water (250 ml), skim milk (500 ml) and whole milk (500 ml); 10 g lactose in lactose-reduced skim (500 ml) and whole milk (500 ml) and whole milk (500 ml); and a placebo (250 ml). There was a significant positive relationship between amount of lactose consumed and symptom response. The form in which the lactose was administered (e.g., whole versus skim milk) was not significantly related to symptoms. It is concluded that in a symptomatic subjects a significantly greater quantity of low-lactose milk than regular milks can be consumed.     

Myeloperoxidase-induced fibrinogen unfolding and clotting

Due to its unique properties and high biomedical relevance fibrinogen is a promising protein for the development of various matrixes and scaffolds for biotechnological applications. Fibrinogen molecules may form extensive clots either upon specific cleavage by thrombin or in thrombin-free environment, for example, in the presence of different salts. Here, we report the novel type of non-conventional fibrinogen clot formation, which is mediated by myeloperoxidase and takes place even at low fibrinogen concentrations (<0.1 mg/ml). We have revealed fibrillar nature of myeloperoxidase-mediated fibrinogen clots, which differ morphologically from fibrin clots. We have shown that fibrinogen clotting is mediated by direct interaction of myeloperoxidase molecules with the outer globular regions of fibrinogen molecules followed by fibrinogen unfolding from its natural trinodular to a fibrillar structure. We have demonstrated a major role of the Debye screening effect in regulating of myeloperoxidase-induced fibrinogen clotting, which is facilitated by small ionic strength. While fibrinogen in an aqueous solution with myeloperoxidase undergoes changes, the enzymatic activity of myeloperoxidase is not inhibited in excess of fibrinogen. The obtained results open new insights into fibrinogen clotting, give new possibilities for the development of fibrinogen-based functional biomaterials, and provide the novel concepts of protein unfolding.     

Identification of two Escherichia coli pseudouridine synthases that show multisite specificity for 23S RNA

Several putative Escherichia coli pseudouridine (Psi) synthases have been identified by iterative searching of genomic databases for ORFs homologous to known Psi synthases [Gustafsson et al. (1996) Nucleic Acids Res. 24, 3756-3762]. Of these, yceC and yfiI were proposed to encode Psi synthases which modify 23S rRNA. In the present work, yceC and yfiI were cloned and overexpressed in E. coli, and the encoded enzymes, YceC and YfiI, were purified to homogeneity. Both proteins converted Urd residues of rRNA to Psi, thus confirming their identities as Psi synthases. However, in in vitro experiments both enzymes extensively modified Urd residues of both 23S rRNA and 16S rRNA. Gene-disruption of yceCresulted in the absence of Psi modification at positions U955, 2504, and 2580 of 23S RNA, thus identifying these sites as in vivo targets for YceC. Likewise, yfiI disruption resulted in the absence of Psi modification at positions U1911, 1917, and possibly 1915 of 23S RNA. Disruption of yceC did not affect the growth under the conditions tested, whereas yfiI-disrupted cells showed a dramatic decrease in growth rate. Since YceC and YfiI hypermodify RNA in vitro, factors in addition to ribonucleotide sequence must contribute to the in vivo specificity of these enzymes.     

Multiple splice variants of phosphodiesterase PDE4C cloned from human lung and testis

Four closely related cyclic-nucleotide specific phosphodiesterase (PDE4) genes have been identified in both humans and rats: PDE4A, 4B, 4C and 4D. We have now cloned cDNAs for multiple splice variants of human PDE4C. Two splice variants, PDE4C-791 and PDE4C-426, were isolated from a fetal lung library. The longest open reading frame (ORF) of 791 amino acids (aa) is encoded by PDE4C-791, which is similar to a recently described cDNA [Engels, P., Sullivan, M., Muller, T. and Lubbert, H. FEBS Lett. 358 (1995) 305-10], except that an alternative 5'-end sequence upstream of the first methionine extends the PDE4C-791 ORF by 79 aa. The PDE4C-426 variant contains 3 insertions that are located 5' to the catalytic domain and encode several in-frame stop codons. The predicted 426 aa protein initiates at a methionine 365 aa within PDE4C-791. A baculovirus clone starting at this methionine expressed an enzymatically active protein. Two additional splice variants, PDE4C-delta54 and PDE4C-delta109, were found in testis mRNA. PDE4C-delta54 contained a novel 5'-end region and a deletion of 162 nt; the predicted protein deletes 54 aa from the amino-terminal region. The PDE4C-delta54 protein produced in baculovirus-infected cells was enzymatically active and sensitive to PDE4-specific inhibitors. The PDE4C-delta109 protein is similar to PDE4C-delta54 but has an additional 55 aa deleted in the catalytic domain; it lacked enzymatic activity. Analysis of uncloned total mRNA from 4 tissue sources by polymerase chain reaction (PCR) confirmed the presence of mRNAs with the two deletions and three insertions that we observed in cDNA clones. The PDE4C-delta54 variant was found only in testis and the 5'-extended region of PDE4C-791 was seen only in lung and the melanoma cell line G361. Hence, tissue-specific expression of various PDE4C isoforms should be considered in understanding how these gene products modulate cellular responses to cAMP.     

Pretransplant injection of allograft recipients with donor blood or lymphocytes permits allograft tolerance without the presence of persistent donor microchimerism

Donor-recipient microchimerism has recently been suggested to play a critical role in the induction and maintenance of allograft tolerance. In this study we sought evidence for this hypothesis using the LEW-to-ACI cardiac allograft as a model system. Donor-specific tolerance to cardiac allografts was induced by intravenous or intraportal injection of graft recipients with donor peripheral blood, T cells, or B cells 7 days before transplantation. All the graft recipients injected with donor antigens accepted donor heart grafts indefinitely when compared with control recipients that rejected donor allografts in 12 days. Long-term graft survivors rejected third-party BN heart allografts in 14 days without an adverse effect on the survival of the first LEW heart allografts, demonstrating the specificity of the tolerance. Tissue lysates prepared from heart, kidney, liver, bone marrow, thymus, lymph nodes, and spleen of tolerant (>120 days) graft recipients were analyzed for the presence of donor DNA using LEW T cell receptor C beta gene-specific primers for polymerase chain reaction that detects donor DNA at > or = 1:10,000 dilution. Donor DNA was detected in 77% of tolerant graft recipients. Chimeric recipients showed variations in the levels and presence of donor DNA in different tissues. The status of donor microchimerism, with respect to its presence and tissue distribution, was dependent upon the donor cell type and route of injection used for the induction of tolerance. Intraportal injection of the graft recipients with donor peripheral blood resulted in the highest degree of chimerism, whereas intravenous injection with donor B cells did not induce detectable microchimerism in this group of recipients. These data clearly demonstrate that the presence of microchimerism is common following administration of donor cells, but that its presence is not an absolute requirement for the long-term survival of allografts.     

CD2 rescues T cells from T-cell receptor/CD3 apoptosis: a role for the Fas/Fas-L system

Anti-CD3 monoclonal antibodies (MoAbs) and glucocorticoid hormones induce apoptosis in immature thymocytes and peripheral T lymphocytes. This process is inhibited by a number of growth factors, including interleukin-2 (IL-2), IL-3, and IL-4, as well as by triggering of the adhesion molecule CD44, which would indicate that signals generated by membrane receptors can modulate the survival of lymphoid cells. To investigate whether triggering of CD2 may also affect apoptosis in lymphoid cells, we analyzed the effect of stimulation with anti-CD2 MoAbs on T-cell apoptosis induced by two stimuli, anti-CD3 MoAbs and dexamethasone (DEX), using a hybridoma T-cell line and a T-helper cell clone. The results show that CD2 engagement decreased anti-CD3 MoAb-induced apoptosis, but did not influence DEX-induced cell death. Furthermore, the decrease appeared to be related to the expression of Fas/APO-1 (CD95) and Fas-ligand (Fas-L). In fact, we show that CD2 stimulation inhibits apoptosis by preventing the CD3-induced upregulation of Fas and Fas-L in a Fas-dependent experimental system. These data suggest that a costimulatory molecule may control a deletion pathway and may therefore contribute to the regulation of peripheral tolerance.     

Waddell signs: distributional properties and correlates

OBJECTIVE: To determine what percentage of patients have none of the five nonorganic behavioral processes known as Waddell signs, and the relational pattern between Waddell signs and somatic complaints, disturbed functional performance, negative treatment attitudes, physical pathology, depression, generalized anxiety, and MMPI-2 validity scales. DESIGN: Case series survey. SETTING: A referral-based multidisciplinary pain center affiliated with a state medical school. PATIENTS: Seventy-five consecutive patients with chronic back pain. INTERVENTION: Medical evaluation and completion of self-report inventories. MAIN OUTCOME MEASURE: Total number of Waddell signs, physical pathology, and pain intensity ratings were assessed by a physician during an initial medical evaluation. Degree of disturbed functional performance and psychological symptoms were assessed by self-report measures at the initial evaluation. RESULTS: Sixty-four percent of the patients had no Waddell signs. Total number of Waddell signs yielded positive and statistically significant correlations (p < or = .05) with depression, disturbed functional performance, somatic complaints, and pain intensity ratings. Correlations of slightly smaller and statistically nonsignificant magnitudes were revealed for Waddell signs with generalized anxiety, negative treatment attitudes, and physical pathology. Waddell signs were unrelated to age, duration of pain, gender, number of lumbar surgeries, and MMPI-2 validity scales. CONCLUSIONS: Taken together, multiple Waddell signs and some of their correlates present various factors that might interfere with optimal response to treatment.     

Unusual features of right and left idiopathic ventricular tachycardia abolished by radiofrequency catheter ablation

Two unusual cases are presented with idiopathic right and left ventricular tachycardia (IVT) with intriguing clinical and electrophysiological characteristics. The first patient with a sustained IVT of right ventricular outflow tract origin, and an electrophysiological mechanism suggesting reentry, had been resuscitated from cardiac arrest. The second patient had an IVT with a left bundle branch block morphology, which originated from the basal-septal region of the left ventricle (left ventricular outflow tract tachycardia). Both patients were cured with radiofrequency catheter ablation, guided by endocardial activation sequence and pace mapping.