Effect of the delivery system on the biodistribution of Ge(IV) octabutoxy-phthalocyanines in tumour-bearing mice

The pharmacokinetic properties of the Ge(IV)-octabutoxy-phthalocyanines (GePc) with two axially ligated triethylsiloxy (GePcEt) or trihexyl-siloxy (GePcHex) chains were studied in BALB/C mice bearing a transplanted MS-2 fibrosarcoma. The GePcs were delivered to mice after incorporation into unilamellar liposomes of dipalmitoyl phosphatidylcholine (DPPC) or in an emulsion of Cremophor-EL. The Cremophor delivered GePcs were cleared from the blood circulation at a much slower rate than the liposome-delivered GePcs. At the same time, Cremophor induced a slower and reduced uptake of the GePcs in the liver and spleen while it greatly enhanced the uptake in the tumour as compared to liposomes. Maximum tumour uptake was observed at 24 h post-injection and was equivalent to 0.67 and 0.50 nmol/g, respectively, for the Cremophor delivered GePcHex and GePcEt. The corresponding values for the liposome-delivered drugs were approximately one fourth of that observed with Cremophor.

Proline-rich (PxxP) motifs in HIV-1 Nef bind to SH3 domains of a subset of Src kinases and are required for the enhanced growth of Nef+ viruses but not for down-regulation of CD4

Human immunodeficiency virus (HIV) and simian immunodeficiency virus Nef proteins contain a conserved motif with the minimal consensus (PxxP) site for Src homology region 3 (SH3)-mediated protein-protein interactions. Nef PxxP motifs show specific binding to biotinylated SH3 domains of Hck and Lyn, but not to those of other tested Src family kinases or less related proteins. A unique cooperative role of a distant proline is also observed. Endogenous Hck of monocytic U937 cells can be specifically precipitated by matrix-bound HIV-1 Nef, but not by mutant protein lacking PxxP. Intact Nef PxxP motifs are dispensable for Nef-induced CD4 down-regulation, but are required for the higher in vitro replicative potential of Nef+ viruses. Thus, CD4 down-regulation and promotion of viral growth are two distinct functions of Nef, and the latter is mediated via SH3 binding.

The first example of anti-Gya detected in Hong Kong

The incidence of anti-Gya is known to be extremely rare, and only a few examples have been reported in Japanese persons and in Caucasians. This case history reports the first example of anti-Gya detected in a Chinese person. The propositus is an 83-year-old male patient whose anti-Gya was revealed because of incompatibility of all units of blood tested by a saline indirect antiglobulin test (SIAT). Although the antibody had a titer of 512 by SIAT, 10 units of Gy(a+) red cells were transfused without any adverse effect.

Determination of DLCO and cardiac output from expired gas slopes with cardiogenic oscillations

Effects of 'cardiogenic oscillations' on alveolar plateau gas concentration slope measurements, constant expiratory pulmonary capillary blood flow, and DLCO determination have not been previously described. We examined cardiogenic oscillations during constant expiratory maneuvers to assess factors influencing magnitude of oscillations as well as effect of oscillatory phase at the start and end of exhalation measurement period on alveolar gas slope. Five normal volunteers performed repeated single breath constant exhalation vital capacity maneuvers using test gas containing 2 physiologically 'inert' gases: Helium (He Mw 4) and argon (Ar Mw 40). The mixture contained 3 absorbable gases, acetylene (C2H2 Mw 26), carbon monoxide (C18O Mw 30), and oxygen. Alveolar plateau slope, magnitude of cardiogenic oscillations, relative signal to noise ratios, and effect of cardiogenic oscillation phase on measured slope were determined for each gas. Cardiogenic oscillations were present for all inert gases. Oscillations were less evident for CO. However, the effects on calculated Qc and DLCO were negligible. Cardiac oscillations of considerable magnitude are seen during single breath constant exhalation maneuvers and affect constant expiratory gas slope calculations. Cardiogenic oscillation phase does not have a significant effect on measured Qc and DLCO using constant expiratory techniques.

Alpha subunit of calcium/calmodulin-dependent protein kinase enhances excitatory amino acid and synaptic responses of rat spinal dorsal horn neurons

1. Here we report that in acutely isolated rat spinal dorsal horn (DH) neurons, the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA)/kainate and N-methyl-D-aspartate (NMDA) receptors can be regulated by endogenous and exogenous calcium/calmodulin-dependent protein kinase II (CaM-KII). Intracellularly applied, the alpha-subunit of CaM-KII enhanced AMPA/kainate and NMDA currents recorded with the use of the whole cell patch-clamp technique. 2. Microcystin, a nonselective phosphatases inhibitor, also enhances AMPA and NMDA responses. 3. Conventional intracellular recordings were made from substantia gelatinosa neurons in spinal cord slices to determine the effect of intracellular application of CaM-KII on excitatory synaptic potentials evoked by electrical stimulation of primary afferent fibers. Excitatory synaptic transmission was enhanced by CaM-KII, which is consistent with the importance of phosphorylation of the postsynaptic AMPA/kainate and NMDA receptor-ion complexes in the short- and long-term changes in synaptic transmission.

Identifying the measurement noise in glaucomatous testing: an artificial neural network approach

Diagnosis of visual function losses in glaucomatous patients depends to a large extent on the analysis of the data collected from corresponding psychophysical tests. One of the main difficulties in obtaining reliable data from patients in these tests is the measurement noise caused by the learning effect, inattention, failure of fixation, fatigue etc. Using Kohonen's self-organising feature map, we have developed a computational method to distinguish between the noise and true measurement and to provide an instant assessment of reliability of the computer-based visual function test. In particular we have experimented with 270 test records from glaucoma patients and glaucoma suspects and found that this method provides a satisfactory way of locating and rejecting noise in the test data, an improvement over conventional statistical methods. This method can also provide doctors with a clear view of the patient's behaviour during the test, thus assisting in their diagnostic decision making process.

Biomechanical comparison between high tibial osteotomy (HTO) and combined HTO and fibular osteotomy

The ojectives of this study were to determine the changes in the lateral ligamentous stability of knee joint that occur after performing high tibial osteotomy with and without fibular osteotomy. Utilizing cadaveric specimens, lateral ligamentous stability was assessed by calculating the length of the lateral collateral ligament, and the lateral opening at different flexion angles when varus stress was applied to the tibia. The Polhemus 3-SPACE system was used to collect motion data describing the six-degrees-of-freedom three-dimensional tibiofemoral motions. It was found that the separation distance between the two attachment points of the lateral collateral ligament decreased by an average of 5 mm at all flexion angles after performing a 5-degree valgus high tibial osteotomy. Performing an additional 5-degrees of osteotomy caused this distance to further decrease. It was further found that performing a fibular osteotomy following a 5-degree valgus high tibial osteotomy produced no changes in the length of the lateral collateral ligament. It was also found that the lateral opening increased an average of 5 mm at all flexion angles after performing a 5-degree valgus high tibial osteotomy. Performing a 10-degree osteotomy caused a further increase in the lateral opening. It was further found that performing a fibular osteotomy following a 5-degree valgus high tibial osteotomy caused the lateral opening to return to its original value. That is to say, the fibular osteotomy negated the lateral opening caused by the tibial osteotomy and produced a pattern of lateral opening similar to the one found in the intact knee.

Binding of Bruton's tyrosine kinase to Fyn, Lyn, or Hck through a Src homology 3 domain-mediated interaction

Bruton's tyrosine kinase (Btk) is a recently described B-cell-specific tyrosine kinase. Mutations in this gene lead to human X chromosome-linked agammaglobulinemia and murine X-linked immunodeficiency. Although genetic evidence strongly suggests that Btk plays a crucial role in B-lymphocyte differentiation and activation, its precise mechanism of action remains unknown, primarily because the proteins that it interacts with have not yet been identified. Here, we show that Btk interacts with Src homology 3 domains of Fyn, Lyn, and Hck, protein-tyrosine kinases that get activated upon stimulation of B- and T-cell receptors. These interactions are mediated by two 10-aa motifs in Btk. An analogous site with the same specificity is also present in Itk, the T-cell-specific homologue of Btk. Our data extend the range of interactions mediated by Src homology 3 domains and provide an indication of a link between Btk and established signaling pathways in B lymphocytes.

Evaluation of a recombinant parasite antigen for the diagnosis of lymphatic filariasis

We evaluated the usefulness of a recombinant parasite antigen (recSXP1) for the serologic diagnosis of lymphatic filariasis. A large proportion of sera from microfilaremic donors living in five different endemic countries (356 of 446 [80%]) contained IgG antibodies to recSXP1, as do sera from approximately 33% of amicrofilaremic patients with acute filarial disease and/or indirect evidence of active filarial infection. Exposure to filarial worms per se does not appear sufficient to elicit an anti-SXP1 antibody response. Thus, this serologic test identifies a large proportion of persons with active lymphatic filariasis among residents of endemic areas.

Block of induction and maintenance of calcium-induced LTP by inhibition of protein kinase C in postsynaptic neuron in hippocampal CA1 region

Calcium-induced LTP (Ca-LTP) refers to the long-lasting potentiation of synaptic transmission in hippocampal synapses that can be induced by a transient (7-10 min) and small increase (from 2 mM to 4 mM) in extracellular calcium concentration. In this paper the effects of protein kinase C (PKC) inhibitors, polymyxin B (PMB) and PKC(19-31), given intracellularly to the postsynaptic neuron in the CA1 region, on the induction and maintenance of Ca-LTP were studied and compared with those found in a similar study earlier made in this laboratory on tetanic stimulation-induced LTP (TS-LTP) [18]. When the intracellular delivery of the inhibitor(s) was made to begin 30 min before the exposure to increased [Ca2+]0, the development of Ca-LTP was completely blocked, leaving only a brief enhancement of EPSPs directly attributable to the brief increase in [Ca2+]0. When the intracellular delivery of either PKC(19-31) alone or PMB+PKC(19-31) was made to begin after the full establishment of Ca-LTP, it soon made the maintained potentiation begin to decline, the EPSP amplitude gradually returning to the control value before the exposure to increased calcium. Thus postsynaptic PKC inhibition blocks both the induction and the maintenance of Ca-LTP, just as it has been shown to do to TS-LTP. But quantitative differences exist: both the induction and the maintenance of Ca-LTP appeared to be more susceptible to block by postsynaptic PKC inhibition than those of TS-LTP.

[Retinal hemorrhage in newborn infants]

The fundi of the 527 infants born within one week were investigated. The results showed that 54 cases (78 eyes) had retinal hemorrhage. Among them, 23 cases (28 eyes) accompanied macular hemorrhage. The retinal hemorrhage in newborn infants was higher in vaginal delivery than in cesarean section, and the incidence of the fetal distress was higher in the newborn infants with macular hemorrhage. The essential causes of the retinal hemorrhage in newborn infants, development of infant macular and the mechanism of amblyopia induced by macular hemorrhage were discussed.

Transient myeloproliferative disorder in a Down's neonate with rearranged T-cell receptor beta gene and evidence of in vivo maturation demonstrated by dual-colour flow cytometric DNA ploidy analysis

Neonates with Down's syndrome may develop a transient myeloproliferative disorder (TMPD) which on presentation is indistinguishable from acute leukemia, with the difference manifest only on follow-up. The clinical course is one of spontaneous remission in TMPD and relentless progression in leukemia. We describe a Down's neonate presenting with hyperleucocytosis and circulating blasts which were positive for CD34, myeloid (CD33), megakaryocytic (CD41, CD42b, CD61), and T-lineage (CD3, CD7), but not B-lineage, associated antigens. Clonal rearrangement of the T-cell receptor beta (TCR beta) gene was found, with the immunoglobulin heavy chain gene in germline configuration, showing the disease to be a clonal proliferation of a multipotential stem cell involving the myeloid and T lineages. Dual-colour flow cytometric DNA ploidy analysis of CD41 positive blasts showed initially a predominant 2N population, but polyploidization to 6N and 8N cells was found on follow-up, concomitant with a progressive decrease in circulating blasts, suggesting maturation of the abnormal clone and a provisional diagnosis of TMPD. This was shown by the eventual resumption of normal haemopoiesis with the disappearance of blasts and the clonally rearranged TCR beta gene.

In vitro survival of skin flora in heparin locks and needleless valve infusion devices

OBJECTIVE

To determine the extent to which two types of infusion devices, the heparin lock and a needleless valve device, allowed the persistence of inoculated microorganisms.

DESIGN

Experiment.

SETTING

Clinical microbiology laboratory.

OUTCOME MEASURES

Bacterial counts in infusion devices.

INTERVENTION

Five of each type of device were inoculated with approximately 10(5) colony-forming units of a strain of Staphylococcus epidermidis and Enterobacter aerogenes and tested for growth at seven time intervals, from 10 minutes to 72 hours after inoculation.

RESULTS

Both strains of bacteria were present in each device at every time interval tested, including 72 hours after inoculation.

CONCLUSIONS

Bacteria introduced into a heparin lock or valve device may be isolated for prolonged periods of time. This suggests that if such devices are contaminated during use, they may be a potential source of infection. The risk of infection should be one major consideration in risk and benefit deliberations when choosing new products.

Induction of H3.3 replacement histone mRNAs during the precommitment period of murine erythroleukemia cell differentiation

Differential hybridization to a cDNA library made from the mRNA of differentiating mouse erythroleukemia (MEL) cells has been used to identify sequences that are induced during the early stages of MEL cell differentiation. One of the differentially expressed genes identified encodes the H3.3 histone subtype. We show here that the three polyadenylated mRNAs produced from the H3.3B gene, as well as the single mRNA produced from the related H3.3A gene, are coordinately induced during the first few hours of MEL cell differentiation and subsequently down regulated as cells undergo terminal differentiation. Nuclear run-on transcription experiments indicate that the accumulation and decay of these mRNAs are controlled at the post-transcriptional level. Unlike the polyadenylated mRNAs of two H1 histone genes that exhibit similar kinetics of induction and decay controlled by c-myc, induction of the H3.3 mRNAs is unaffected by deregulated expression of c-myc.

Childhood acute lymphoblastic leukaemia presenting with relapsing hypoplastic anaemia: progression of the same abnormal clone

A 13-year-old girl presented with two spontaneously reversible episodes of marrow hypoplasia. She subsequently developed acute lymphoblastic leukaemia (ALL) 8 months later. Southern analysis showed identical clonal immunoglobulin heavy chain gene rearrangement bands in the leukaemic cells as well as the marrow cells obtained at the two hypoplastic episodes. Hypoxanthine phosphoribosyl transferase polymorphism studies showed that the ALL blast cells, bone marrow and peripheral blood cells during the two hypoplastic episodes all exhibited clonal haematopoiesis with the same X-chromosome inactivated. This case provides strong evidence that aplastic anaemia and ALL may represent evolution of the same abnormal clone.

Intra-hepatic-arterial infusion of misonidazole--an experimental study of regional radiosensitisation by intraarterial embolisation

The purpose of this study was to generate a selective radiosensitising effect by the intra-hepatic-arterial infusion of misonidazole (MISO). MISO (10 mg) was infused after transcatheter hepatic-arterial embolisation into the livers of rabbits bearing VX2 liver cancer. This procedure was followed by 15 Gy electron irradiation. Evaluation of tumour volume and histological examination was carried out on the 7th day after treatment. The greatest tumour response was obtained in the group which received MISO followed by radiation and was characterised by extensive fibrosis around the tumour and nearly complete tumour necrosis. Liver cell regeneration was also noted in adjacent liver tissue. The advantages of regional infusion of MISO following hepatic-arterial embolisation are: (1) Selectivity increased radiosensitivity of liver cancer alongside very low drug concentration in the plasma. (2) Reduced or absent deleterious side effects of MISO with higher tumour/normal tissue ratios of drug concentration. (3) Reduced cost due to the lower dosage of MISO required for regional infusion.

[Pharmacological activities of musk. IV. Effects of musk on arachidonic acid metabolism in leukocytes from rat inflammatory exudate]

The present work was designed to further study the mechanism of the anti-inflammatory action of musk from the viewpoint of arachidonic acid (AA) metabolism: 1) effect on AA release; 2) action on leukotriene B4 (LTB4) and 5-HETE biosyntheses. Leukocytes obtained from rat inflammatory exudate by i.p. injection of 1% carrageenan were labelled with 14C-AA at 37 degrees C for 2 h. The 14C-AA labelled cells were incubated with the water soluble fraction of musk (MWF) and stimulated with calcium ionophore A23187 to release AA. The radioactivity released from the labelled leukocytes was determined as a criterion of AA release. In order to observe the influence of musk on the biosyntheses of LTB4 and 5-HETE, leukocytes were incubated with MWF and AA, and then stimulated with A23187. The LTB4 and 5-HETE produced were determined by RP-HPLC. The results showed that AA release decreased to 50-70% of the control at MWF concentration of 6.25-37.5 micrograms/ml. The biosyntheses of LTB4 and 5-HETE were not affected. However, AA release increased to 1.5-fold at the MWF concentration of 400 micrograms/ml. At the same time, biosyntheses of LTB4 and 5-HETE decreased by 66.7 and 90%, respectively, as compared with controls. This result indicates that MWF not only inhibited phospholipase A2 (PLA2) activity, but also prevented AA peroxidation and inhibited LTB4 biosynthesis. These results suggest that inhibition of the AA metabolic pathway may play a major role in the mechanism of the anti-inflammatory action of musk.

Widespread differentiation stage-specific expression of the gene encoding phosphoprotein p19 (metablastin) in mammalian cells

p19 is a highly conserved 19 kD cytosolic protein that undergoes phosphorylation in response to diverse extracellular factors in mammalian cells. Its expression is abundant in brain and testis and is developmentally regulated. To gain insights regarding its function, we analyzed the expression of p19 mRNA in a variety of cell types during induction of differentiation. Murine erythroleukemia cells showed a moderate increase followed by a marked decrease in the abundance of p19 mRNA during induction of differentiation. In murine C2 myoblasts and primary fetal rat osteoblasts, p19 mRNA was abundant in replicating cells and decreased to undetectable levels during differentiation. In resting human peripheral blood lymphocytes, p19 mRNA was virtually undetectable but was strongly induced during blast transformation of both B and T cells. In rat liver, p19 mRNA was abundant on embryonic day 17 and decreased during early postnatal development. Upon fractionation of adult rat liver cells by centrifugal elutriation, p19 mRNA was not detected in hepatocytes while a low level was observed in a fraction enriched in non-parenchymal epithelial cells. CCl4-induced liver regeneration resulted in induction of p19 mRNA in hepatocytes. Primary cultures of embryonic and neonatal rat brain were analyzed by indirect immunofluorescence using co-staining with stage-specific markers. p19 expression was restricted to immature neurons and oligodendrocyte precursors. In contrast to the other cell types examined, the neuronal and glial precursors that express p19 were shown, using BrdU labeling, to be postmitotic both in primary culture and in vivo. The data demonstrate widespread, stage-specific expression of p19 and suggest that the protein exerts a general, lineage-independent function during induction of differentiation of mammalian cells. In view of the available evidence on the stimulation of serine phosphorylation of p19 by several growth factors, our working hypothesis is that phosphorylation of p19 may be involved in the mechanism by which growth factors control cell differentiation.

Rearrangement of BCR genes in malignant lymphoma

The Philadelphia chromosome, originally thought to be associated solely with chronic myelogenous leukemia (CML), has since been identified in acute leukemias and in some cases of lymphoma. The Philadelphia chromosome results from reciprocal translocation of genetic material between chromosome 9 and 22 involving the c-abl and BCR genes respectively. Southern blot analysis of the BCR genes was carried out on biopsy specimens from 49 patients presenting with malignant lymphoma without a previously documented CML phase. In two patients, BCR gene rearrangements were detected in the malignant lymph nodes but not in the bone marrow samples. A third patient showed BCR gene rearrangements in the bone marrow but not in the lymph node. From this limited study, it seems that the overall incidence of BCR gene rearrangement in malignant lymphoma is similar to that observed in adult AML.

Expression of stem cell factor and c-kit mRNA in cultured endothelial cells, monocytes and cloned human bone marrow stromal cells (CFU-RF)

Previously, we have shown that conditioned medium from a subpopulation of human marrow stromal cells (CFU-RF) contain an activity able to stimulate the growth of macroscopic epo-dependent erythroid colonies. The ligand for the product of the c-kit proto-oncogene (also known as stem cell factor or SCF), among other activities, has been reported to have similar effects on erythroid colony growth. We have also presented data showing that SCF together with phytohemagglutinin-stimulated leukocyte conditioned medium can stimulate erythroid colony growth in the presence of antibodies to erythropoietin. Using the human SCF cDNA probe (K. Zsebo, Amgen Inc.) we now show that cells derived from CFU-RF colonies express SCF but not c-kit. Human umbilical vein endothelial cells were also found to express SCF and this expression was increased by addition of monocyte supernatant, IL-1 beta or thrombin. Cells of the human erythroleukemia cell line HEL were found to express c-kit but not SCF. Neither c-kit nor SCF mRNA were detected in phytohemagglutinin-stimulated lymphocytes. Together, these data support the view that the behaviour of proliferating erythroid stem cells in the marrow, which may express c-kit, could be regulated by membrane-bound SCF present on surrounding stromal cells.

Anti-hepatitis C virus (HCV) screening at a Canadian Red Cross center: significance of a positive c100 HCV enzyme-linked immunosorbent assay

The c100 hepatitis C virus (HCV) enzyme-linked immunosorbent assay (ELISA) has been used to screen blood donors to prevent transfusion-associated non-A,non-B hepatitis. This test is not specific, and only about 25 percent of c100 HCV ELISA-positive blood samples appear to transmit hepatitis C. However, the intensity of the ELISA (sample/cutoff ratio [S/C], greater than 2) could identify a subpopulation of donors that are at high risk for transmitting hepatitis. Blood samples from 20,186 volunteer blood donors at a Canadian Red Cross blood transfusion center were screened for antibodies to HCV using the c100 HCV ELISA. Fifty-nine (0.3%) of these donors were repeatably reactive on ELISA. When their samples were tested with the c100 recombinant immunoblot assay (RIBA) and second-generation RIBA (RIBA-2), 26 (44%) and 31 (52%) samples, respectively, were found to be positive. Thirty-three of the 59 ELISA-reactive donors had an S/C greater than 2. Of these 33 donors, 30 (91%) had elevated alanine aminotransferase (ALT), 27 (82%) were RIBA-2 positive, and 22 (67%) had risk factors for hepatitis. In contrast, of the 26 ELISA-reactive donors with S/C less than 2, only 7 (27%) had elevated ALT, and 4 (15%) were RIBA-2 positive and also had high risk factors for hepatitis. Thus, while the HCV ELISA may lack specificity, its intensity can serve to identify a subgroup of donors that are at high risk for transmitting hepatitis.

Lipoprotein receptor activity of peritoneal macrophages from insulin-deficient mice

Binding, uptake and degradation of 125I-labeled normal very low density lipoprotein (125I-n-VLDL) from normal swine plasma and 125I-labeled beta-migrating VLDL (125I-beta-VLDL) from hypercholesterolemic rabbit plasma by peritoneal macrophages of mice rendered insulin-deficient by streptozotocin (250 mg/kg) were studied. It was found that the amount of binding, uptake and degradation of 125I-n-VLDL by macrophages from the diabetic mice was 2-fold or 2.5-fold higher than by macrophages from normal mice, resulting from an increase in the binding capacity of VLDL receptors on the macrophages from the insulin-deficient rodents. In contrast, the binding, uptake and degradation of 125I-beta-VLDL by macrophages from diabetic mice were reduced to only about 45% of normal levels because of a decrease in the number and affinity of the receptors for beta-VLDL. These experimental results indicate that n-VLDL is more important than beta-VLDL in the pathogenesis of atherosclerosis in insulin-dependent diabetes.

Molecular characterization of beta-thalassaemia in 174 Greek patients with thalassaemia major

The mutations producing beta-thalassaemia in 174 Greek patients with thalassaemia major were investigated by dot-blot hybridization of oligonucleotide probes to genomic DNA amplified by the polymerase chain reaction procedure, by direct sequencing of amplified DNA, and by gene mapping. beta-thalassaemia in Greeks was found to be very heterogeneous at the molecular level as 17 different mutations were observed: 86.6% of the beta-thalassaemic genes, however, could be identified with five probes: IVS-I-110 (G----A) (42.5%), codon 39 (C----T) (17%), IVS-I-1 (G----A) (13.2%), IVS-I-6 (T----C) (7.2%) and IVS-II-745 (C----G) (6.9%). Several mutations which had not previously been reported in the Greek population and which occurred at an incidence of 2% or lower were observed in this study. The information obtained will facilitate the prenatal diagnosis of beta-thalassaemia in Greece.

[The role of lipoxygenase and cyclooxygenase metabolites in acute hypoxic pulmonary vasoconstriction in piglets]

The role of lipoxygenase and cyclooxygenase metabolites in acute hypoxic pulmonary vasoconstriction (HPV) was studied in piglets. It has been found that acute alveolar hypoxia induced remarkable pulmonary vasoconstriction, associated with an increase in cardiac output. The hypoxic pulmonary vasoconstriction response was insignificantly attenuated after infusion of DEC. Indomethacin potentiated markedly the increase in pulmonary artery pressure and pulmonary vascular resistance and thus augmented HPV. It is inferred that hypoxic pulmonary vasoconstriction in piglet may be mediated by other important mediators in addition to leukotrienes, but modulated by prostaglandins to prevent an excessive rise in pulmonary artery pressure.

Accessory cells in immune suppression. III. Evidence for two distinct accessory cell-dependent mechanisms of T lymphocyte-mediated suppression

Suppression of antibody secretion by the 2,4,6-trinitrophenol (TNP)-binding BALB/c myeloma, MOPC 315, by idiotype- and hapten-reactive suppressor T cells is mediated by secreted factors (TsF) and requires the presence of accessory cells (AC). Idiotype-specific TsF functions only in the presence of Ia+ AC and is completely idiotype specific. Moreover, no suppression is observed when myeloma targets and AC are separated by cell-impermeable membranes, indicating that the role of AC may be to bind, focus, and/or present TsF to the myeloma cells. In contrast, TNP-specific TsF inhibits myeloma function in the presence of TNP-protein and activated macrophages that are not Ia+. This form of suppression is nonspecific at the effector stage; i.e., anti-TNP TsF inhibits a non-TNP binding cell line, TEPC 15, as long as TNP-protein and activated macrophages are present. Moreover, suppression occurs even when myeloma targets and AC are separated by cell-impermeable membranes. These results are consistent with the view that hapten-reactive TsF binds to antigen on the surface of macrophages and induces these cells to secrete nonspecific immunosuppressive molecules. Thus, different types of AC may play fundamentally different roles in TsF-mediated suppression; they may either bind and present TsF to targets (as in the case of idiotype-specific TsF) or secrete nonspecific immunosuppressants as a consequence of a TsF-antigen interaction (hapten-specific TsF). Autonomous, suppressible targets provide valuable experimental systems for analyzing the cellular interactions in T cell-mediated suppression.

Accessory cells in immune suppression. III. Evidence for two distinct accessory cell-dependent mechanisms of T lymphocyte-mediated suppression

Suppression of antibody secretion by the 2,4,6-trinitrophenol (TNP)-binding BALB/c myeloma, MOPC 315, by idiotype- and hapten-reactive suppressor T cells is mediated by secreted factors (TsF) and requires the presence of accessory cells (AC). Idiotype-specific TsF functions only in the presence of Ia+ AC and is completely idiotype specific. Moreover, no suppression is observed when myeloma targets and AC are separated by cell-impermeable membranes, indicating that the role of AC may be to bind, focus, and/or present TsF to the myeloma cells. In contrast, TNP-specific TsF inhibits myeloma function in the presence of TNP-protein and activated macrophages that are not Ia+. This form of suppression is nonspecific at the effector stage; i.e., anti-TNP TsF inhibits a non-TNP binding cell line, TEPC 15, as long as TNP-protein and activated macrophages are present. Moreover, suppression occurs even when myeloma targets and AC are separated by cell-impermeable membranes. These results are consistent with the view that hapten-reactive TsF binds to antigen on the surface of macrophages and induces these cells to secrete nonspecific immunosuppressive molecules. Thus, different types of AC may play fundamentally different roles in TsF-mediated suppression; they may either bind and present TsF to targets (as in the case of idiotype-specific TsF) or secrete nonspecific immunosuppressants as a consequence of a TsF-antigen interaction (hapten-specific TsF). Autonomous, suppressible targets provide valuable experimental systems for analyzing the cellular interactions in T cell-mediated suppression.

Multiple myeloma with initial presentation in the jaw: a clinical-pathologic discussion

A 39-year-old white female presented with jaw pain initially interpreted as a manifestation of an odontogenic infection. Mandibular radiographs revealed lytic lesions suggesting a diagnosis of myeloma, which was subsequently confirmed by abnormalities in serum and urinary proteins and in bone marrow. Chemotherapy produced a transient response, but eventual relapse with extramedullary plasmacytomas and plasma cell leukemia led to death. The clinicopathologic implications of this case are presented and discussed.

A methodological basis for SEM autoradiography: biosynthesis and radioligand binding

A method is described for scanning electron microscope (SEM) autoradiography whereby preservation of high resolution cell surface details is retained together with degelatination of the emulsion without gross loss or redistribution of silver grains. This method should provide a convenient medium-sized marker for SEM (using secondary, backscattered electron and X-ray imaging) topographic studies of biosynthesized molecules, and of cell surface receptors and antigens, using indirect or direct labelling procedures with radio-labelled ligands.

Idiopathic acquired sideroblastic anaemia transforming to acute myelosclerosis

A case of idiopathic acquired sideroblastic anaemia transforming to acute myelofibrosis is reported. The appearance of atypical megakaryocytic proliferation in idiopathic acquired sideroblastic anaemia may presage the development of an acute myelofibrotic phase of this usually chronic disease.

Alteration of glucose and insulin metabolism in congenital heart disease

Children with left-to-right shunt, with and without congestive heart failure, were found to have impaired glucose tolerance tests (GTT). In cyanotic children normal levels of glucose were found in association with abnormally high levels of insulin following oral GTT. Several possible mechanisms are proposed to explain the different glucose tolerance alterations: (1) Suppression of insulin release appeared to partially explain the low levels of insulin in congestive heart failure. This suppression may be related to the high levels of circulating norepinephrine found in these patients. (2) Excessive clearance of insulin by the lung may also be responsible for the reduced arterial insulin levels in patients with left-to-right shunt, and underclearance of insulin for the abnormally higher arterial insulin levels in patients with right-to-left shunts in whom a significant amount of venous blood has bypassed the lung. (3) Hypoxia of the pancreas and the liver in cyanotic patients and those with congestive heart failure may explain the reduction of insulin levels in the hepatic vein following i.v. glucose tolerance tests. An excess production of a glucagonlike gastrointestinal factor in cyanotic children may partially explain the abnormally high levels of insulin following oral GTT.