A murine model of antibody-mediated hyperacute rejection by galactose-alpha(1,3)galactose antibodies in Gal o/o mice

BACKGROUND

In pig-to-primate/human xenografts, hyperacute rejection of primarily vascularized organs usually occurs in 10-60 min and is due to the reaction of the recipients' natural antibodies with antigens expressed on the donor endothelium, the fixation of complement, and ultimately vascular stasis and hemorrhage. Surprisingly, the major target of the natural antibodies is the disaccharide galactose-alpha(1,3)galactose (Gal alpha(1,3)Gal), which is found on many different molecules in pig tissues and reacts with naturally occurring human anti-pig IgM and IgG antibodies. There are a number of strategies to remove/block/alter Gal alpha(1,3)Gal expression in pig tissues, all of which involve the expression of transgenes in pigs. To overcome the difficulty of preclinical studies using primates, we describe a model of hyperacute rejection of heart transplants to Gal o/o mice, which are similar to humans in that they have anti-Gal alpha(1,3)Gal antibodies.

METHODS

Gal o/o mice received skin or heart grafts from Gal+ mice or rats, and additional antibody and complement were provided; hyperacute rejection was monitored by observation and histology.

RESULTS

Gal alpha(1,3)Gal+ mouse tissues (skin or heart) are not rejected by Gal o/o mice. This was not unexpected, as mice do not utilize alloantibody/complement systems satisfactorily in experimental transplantation studies. However, with the addition of anti-Gal alpha(1,3)Gal antibody and complement, hyperacute rejection of hearts can occur in 10-20 min; it is mediated by IgM, not IgG, antibodies and leads predominantly to tissue hemorrhage.

CONCLUSION

Gal alpha(1,3)Gal antigen modification by expression of the H transferase cDNA leads to "indefinite" survival (>120 min) and no hyperacute rejection, which shows that this model is suitable for the study of antibody-mediated rejection of relevance to pig-to-human xenografts.

[Co-existence of glutamate and substance P in electrophysiologically identified dorsal root ganglion neurons of rats]

Electrophysiological properties, reaction to substance P (SP) receptor agonist, and co-existence of glutamate (Glu) and SP in neurons of the spinal dorsal root ganglion (DRG) of the rat were investigated in vitro. The main results were: (1) According to the fiber conduction velocity, totally 135 intracellularly recorded DRG neurons were divided into A alpha/beta type (> 12 m/s) and C type (< 1.3 m/s). There were remarkable differences between the fast after hyperpolarization (fAHP) of action potential between the two types: fAHP of C type neurons had smaller amplititude and longer duration, whereas the fAHP of A alpha/beta type neurons had larger amplititude and shorter duration. (2) Among 22 DRG neurons of which overshoots of action potential appeared, specific SP receptor agonist Sar-SP induced depolorization in 42% (5/12) of the A alpha/beta type neurons and 80% (8/10) of the C type neurons. (3) Biocytin was intracellularly injected into the 22 Sar-SP administrated DRG neurons. After fixation and section, employing the immunofluorescent histochemical multi-staining technique for phosphate-activated glutaminase (PAG, a specific marker for glutamatergic neurons), SP and biocytin, 25% (3/12) of the A alpha/beta type neurons and 80% (8/10) of the C type neurons showed both PAG- and SP-like immunoreactivities. There was a great difference between the percentages of the PAG/SP co-existing A alpha/beta type neurons and C type neurons (P < 0.05). The present results indicated that there were some differences in chemicoanatomical and electrophysiological properties between A alpha/beta type and C type neurons, and SP might facilitate the discharge of DRG neurons through activating SP autoreceptors on their membrane.

Influence of tyrosine and phenylalanine limitation of cytotoxicity of chimeric TGF-alpha toxins on B16BL6 murine melanoma in vitro

Previous research in animals supports the use of tyrosine and phenylalanine (Tyr-Phe) restriction as an adjuvant to the treatment of cancer. In this regard, dietary restriction of Tyr-Phe specifically inhibits the growth of B16BL6 melanoma tumors, dramatically suppresses spontaneous hematogenous metastasis, and modulates the sensitivity of these tumor cells to growth factors. Two chimeric toxins, HB-TGF alpha-PE4EKDEL and TGF alpha-PE4EKDEL, were examined for their toxicity against the B16BL6 melanoma cell line, and the ability of Tyr-Phe limitation to modulate the potential of these toxins was examined. Tyr-Phe limitation significantly enhanced the cytotoxic effects of HB-TGF alpha-PE4EKDEL approximately 10-fold toward B16BL6 melanoma, and free heparin diminished the cytotoxicity of HB-TGF alpha-PE4EKDEL. Although TGF alpha-PE4EKDEL is cytotoxic to this cell line, Tyr-Phe limitation did not effect the cytotoxicity of this toxin. Tyr-Phe limitation inhibited the synthesis and secretion of heparin-binding proteins but did not alter the expression of surface heparan sulfate proteoglycans. These data suggest that cell surface heparan sulfate proteoglycan is a target for binding and execution of the cytotoxicity of HB-TGF alpha-PE4EKDEL and that augmentation of cytotoxicity by Tyr-Phe limitation is due to the inhibition of heparin-binding protein production.

Immunocytochemical localization of mu-opioid receptor in primary afferent neurons containing substance P or calcitonin gene-related peptide. A light and electron microscope study in the rat

Co-expression of mu-opioid receptor-like immunoreactivity (MOR-LI) with substance P (SP)- or calcitonin gene-related (CGRP)-LI was observed in rat trigeminal and dorsal root ganglion neurons. In particular, MOR-LI was found in axon terminals with SP- or CGRP-LI in laminae I and II of the medullary and spinal dorsal horns. MOR may be implicated in modulation of release of SP and CGRP from primary sensory afferents.

[Dynamic changes of angiotensin II type-1 receptor mRNA expression in volume-overloaded ventricular hypertrophy]

Using reverse transcriptase-polymerase chain reaction (RT-PCR) the changes of the angiotensin II receptor subtype 1-a (AT1a) and 1-b (AT1b) mRNA levels were examined in hypertrophied ventricles caused by ventral aorta-caval fistula of SD rats. The results show as follows. (1) Three days after operation, the ventricular weight increased significantly, whereas the level of AT1a and AT1b mRNA in both ventricles remained unchanged. (2) Twelve days after operation, the weight increase of both ventricles was more evident, the levels of AT1a and AT1b mRNA in the right ventricle increased (by 62.6% and 72.0%), as compared with control. In the left ventricle, on the other hand, the level of AT1a mRNA increased by 79.0%, while the level of AT1b mRNA showed no obvious increase. (3) Thirty-five days after operation, the levels of AT1a and AT1b mRNA in both ventricles increased still more significant, (i.e., 70.0% and 83.9% in the right and 96.5% and 86.9% in the left). Moreover, 12 d and 35 d after operation, the level of AT1a mRNA was higher than that of AT1b mRNA in both ventricles. (4) There was a positive correlation between the degree of ventricular hypertrophy with the level of AT1 mRNA in ventricular myocardium (r = 0.6168-0.8223). The results suggest that the increased mRNA expression of AT1 in myocardial hypertrophy caused by volume overload may be a mechanism underlying the increased responsiveness of hypertrophic myocardial cells to Ang II, and a difference in the expression between AT1a and AT1b mRNAs in myocardial hypertrophy may be related to the different physiological or pathophysiological roles of Ang II, mediated by the two subtypes of AT1.

[Peripheral substance P receptor mediating c-fos gene expression in the spinal dorsal horn induced by peripheral noxious stimulation]

Employing immunohistochemical staining for FOS protein, which is the expression product of c-fos proto-oncogene, the role of substance P receptor (SPR) in noxious information transmission at peripheral terminals of the dorsal root ganglion cells was investigated by means of a selective SPR antagonist L668, 169 and agonist Sar-SP. Unilateral injection of L668, 169 (10(-4) mol/L) into the plantar of hindpaw 10 min before injection of 4% formalin, the number of FOS-like immunoreactive (LI) neurons in the superficial laminae of dorsal horn was significantly decreased, but the changes were not obvious in the deeper laminae. Smaller doses of L668, 169 (10(-5), 10(-6) mol/L) were almost ineffective on FOS-LI neurons in both the superficial and the deeper laminae. However, Sar-SP (10(-4) mol/L) or formalin did result in the expression of c-fos gene in the superficial laminae of the dorsal horn. These results indicated that SP might contribute to the transmission of nociceptive information and induce noxious sensation, at least in part by activating SPR in peripheral terminals of the dorsal root ganglion cells.

Combination therapy of active hexose correlated compound plus UFT significantly reduces the metastasis of rat mammary adenocarcinoma

Synergistic effects of active hexose correlated compound (AHCC) extracted from mushroom on the treatment with UFT against mammary adenocarcinoma, SST-2 cells, in congenitally T cell-depressed spontaneously hypertensive rats (SHR) were observed. AHCC plus UFT had slight but significant effects on the growth of primary tumors. Pulmonary metastases were not inhibited by the treatment with AHCC plus UFT, whereas metastases to axillary lymph nodes (LN) were obviously inhibited. Combination of AHCC plus UFT showed similar synergistic anti-metastatic effects in SHR rats with accelerated pulmonary metastases following the surgical removal of the primary tumors. In vitro studies demonstrated that AHCC plus UFT enhanced the NK cell activity in tumor-bearing rats, whereas UFT alone depressed the NK cell activity. AHCC plus UFT also enhanced the NO production and cytotoxicity of peritoneal macrophages. In addition, AHCC restored the suppressed mRNA expression of interleukin-1alpha and tumor necrosis factor-alpha induced by the chemotherapy. Taken together, the combination of AHCC plus UFT brought about good therapeutic effects not only on primary tumor growth but also on reducing metastasis and these effects were mediated by host immunity which was restored or activated by AHCC. AHCC may be a good candidate for a biological response modifier.

Protein kinase C mediates the signal for interferon-gamma mRNA expression in cytotoxic T cells after their adhesion to laminin

A cytotoxic T-cell line, CTLL-2 cells, showed spreading after adhering to extracellular matrix proteins such as fibronectin (FN), laminin (LN) and hyarulonic acid (HA). The adhesion of CTLL-2 cells to LN was mediated by very late activation antigen-6 (VLA-6). Expression of interferon-gamma (IFN-gamma) mRNA was enhanced in CTLL-2 cells, also when they adhered to extracellular matrix proteins; and the enhanced IFN-gamma mRNA expression by adhering to LN was blocked by anti-alpha 6 antibody. Calphostin C, a protein kinase C (PKC) inhibitor, markedly inhibited the enhancement of IFN-gamma mRNA expression in a dose-dependent manner, which suggested that PKC acted as a second messenger in the IFN-gamma mRNA expression mediated by the interaction of VLA-6 with LN in CTLL-2 cells. Furthermore, confocal laser-microscopic analysis and Western blot analysis revealed that PKC-alpha was activated after CTLL-2 cells adhered to LN. PKC activity translocated from the cytosol fraction to the particulate fraction, after CTLL-2 cells adhered to LN. Altogether, we suggest that PKC plays an important role in the signal transduction for IFN-gamma mRNA expression after cytotoxic T cells adhere to LN.

Generation and applications of amplitude-squeezed states of light from semiconductor diode lasers

We describe recent experiments on generation and applications of amplitude-squeezed states of light from a semiconductor diode laser. Amplitude-squeezed light with intensity noise 2 dB below the standard shot- noise limit was observed from a diode laser with a weak optical feedback from an external grating. Applications of this amplitude-squeezed light as a local oscillator in heterodyne detection in Doppler velocity measurement and weak light-scattering measurement are discussed.

Functional interactions among cytoskeleton, membranes, and cell wall in the pollen tube of flowering plants

The pollen tube is a cellular system that plays a fundamental role during the process of fertilization in higher plants. Because it is so important, the pollen tube has been subjected to intensive studies with the aim of understanding its biology. The pollen tube represents a fascinating model for studying interactions between the internal cytoskeletal machinery, the membrane system, and the cell wall. These compartments, often studied as independent units, show several molecular interactions and can influence the structure and organization of each other. The way the cell wall is constructed, the dynamics of the endomembrane system, and functions of the cytoskeleton suggest that these compartments are a molecular "continuum," which represents a link between the extracellular environment and the pollen tube cytoplasm. Several experimental approaches have been used to understand how these interactions may translate the pollen-pistil interactions into differential processes of pollen tube growth.

[Oleanolic acid saponins from the root bark of Aralia taibaiensis]

Five oleanolic acid saponins were isolated from the root bark of Aralia taibaiensis Z.Z. Wang et H.C. Zheng. By spectroscopic and chemical methods, they were identified as araloside A (1), 3-O-[alpha-L-arabinofuranosyl(1-->4)-6'-O-n-butyl-beta-D- glucuronopyranosyl]-oleanolic acid-28-O-beta-D-glucopyranoside (2), 3-O-[alpha-L-arabinofuranosyl(1-->4)-6'-O-ethyl-beta-D- glucuronopyra-nosyl]-oleanolic acid-28-O-beta-D-glucopyranoside (3), stipuleanoside R2(4) and 3-O-(beta-D-glucopyranosyl(1-->3) [alpha-L-arabinofuranosyl(1-->4)]-6'-O-ethyl-beta-D- glucuronopyranosyl)-oleanolic acid-28-O-beta-D-glucopyranoside (5). Saponin 1 and 4 were isolated from the title plant for the first time. 2, 3 and 5 are new compounds and named taibaienoside I, taibaienoside II and taibaienoside III, respectively.

Association of serotonin-like immunoreactive axons with nociceptive projection neurons in the caudal spinal trigeminal nucleus of the rat

Serotoninergic projections to the spinal dorsal horn are implicated in the modulation of nociceptive transmission. However, morphological evidence indicating that serotoninergic projection fibers make synapses on nociceptive neurons in the medullary dorsal horn is still meager. Thus, we examined whether axonal varicosities with serotonin (5-HT)-like immunoreactivity (5-HT-LI) might make synapses on nociceptive projection neurons in the caudal spinal trigeminal nucleus (Vc) of the rat. Projection neurons were retrogradely labeled with tetramethylrhodamine-dextran amine (TMR-DA) or wheat germ agglutinin-horseradish peroxidase (WGA-HRP) that was injected into the parabrachial or thalamic region. Vc neurons in which c-fos protein-like immunoreactivity (Fos-LI) was induced by subcutaneous injection of formalin into the lip were considered nociceptive. Vc neurons in direct contact with axonal varicosities that bind isolectin I-B4 were also considered nociceptive. Triple labeling for 5-HT, TMR-DA, and Fos as well as that for 5-HT, TMR-DA, and I-B4 were done by using the immunofluorescence and fluorescence histochemical techniques. Confocal laser-scanning microscopy revealed that axonal varicosities with 5-HT-LI were in close apposition to TMR-DA-labeled neurons showing Fos-LI in lamina I and the outer part of lamina II (lamina IIo), and that both axonal varicosities with 5-HT-LI and those binding I-B4 were in close apposition to single neuronal profiles labeled with TMR-DA. The presumed nociceptive neuronal profiles in close apposition to axon terminals with 5-HT-LI were mainly those of laminae I and II neurons as well as dendrites of lamina III neurons. Electron microscopy confirmed that axon terminals with 5-HT-LI and those with I-B4 binding activity in laminae I and II made synapses on somatic and dendritic profiles that were labeled with WGA-HRP. The results indicate that serotoninergic neurons project directly on nociceptive projection neurons in the Vc.

Biochemical assessment of cellular damage after adipocyte harvest

Free fat transplantation for soft tissue augmentation yields variable results, which may be related to the technique of fat harvest. To compare the viability of adipocytes harvested by liposuction (sal) or by excision (exc), fat harvested by both techniques from seven lipectomy patients was analyzed by glycerol-3-phosphate dehydrogenase (G3PDH) enzyme assay. Leakage of this lipogenic enzyme through the plasma membrane is a potential indicator of fat cell damage. Preliminary experiments showed this assay to be sensitive and specific for adipocyte G3PDH activity. Treatment of fat tissue with collagenase H resulted in complete release of the component fat cells for analysis with less loss of G3PDH activity, compared to other collagenase preparations. Each sample was digested and separated into three compartments: mature adipocytes-floating layer (F), acellular supernatant (S), and stromal pellet (P). Samples from each compartment were assayed for G3PDH activity, normalized to DNA content, and represented as a percentage of the whole (F + S + P). Within the subgroups, the fat cell fraction of the liposuction samples (Fsal) showed statistically more activity than the excised samples (Fexc) by paired Student's t test (P = 0.004). The supernatant (representing leaked G3PDH) and pellet fractions of excised samples revealed more G3PDH activity than the same fractions from liposuctioned tissue; the former (Sexc) to a significant degree (P = 0.036). Using this assay, the results indicate that liposuction fat harvest does not result in increased fat cell damage compared to fat harvested by excision.

Clonality and life cycles of intestinal crypts explained by a state dependent stochastic model of epithelial stem cell organization

The organization and control of stem cells is a key issue in epithelial cell biology. The small intestinal murine crypt is a useful tissue to study such problems since stem cells are known to be located at specific positions at the bottom of the crypt where they are self maintaining. Recent data suggest, that (1) the number of active stem cells in a crypt can fluctuate, (2) the immediate progeny of a single stem cell can replace other stem cells eventually leading to monoclonality and (3) the life cycle of crypts may be linked to stem cell dynamics. It is the objective of this paper to suggest a stochastic state-dependent model of stem cell and crypt growth which can explain and-link these phenomena into one comprehensive framework. Monte Carlo simulations are performed to show consistently with available data. The model explains the size distribution of small intestinal crypts in steady state, the observations of stem cell fluctuations and monoclonality conversion, recovery of the crypt population after moderate damage and the rate of crypt fission and extinction. The key assumption of this model is an autoregulatory control of stem cell growth.

Radiation-induced apoptosis in the rat spinal cord: lack of equal effect per fraction

This study assessed the apoptotic response in the rat spinal cord following split-dose and fractionated irradiation. The cervical spinal cord (C2-T2) of adult female Fisher 344 rats was irradiated with a single, two, three or four daily fractions of 8 Gy, or two doses of 8 Gy separated by an interval of 0, 1, 2 or 4 h, or 1, 2, 3, 6, 10, 14, 28 or 63 days between two doses. Animals were sacrificed at 0, 4, 8, 12 and 24 h after each final 8-Gy dose, and the percentage of apoptotic glial cells was scored histologically according to specific morphological features of apoptosis. After a single dose of 8 Gy, the percent of apoptotic glial cells increased at 4 h (0.29 +/- 0.02%), peaked at 8 h (1.04 +/- 0.06%) and returned to the baseline by 24 h (0.05 +/- 0.01%). The total apoptotic yield (TAY) per spinal cord section over a 24-h period after a single 8-Gy dose was 9.04 +/- 0.34%. The second, third and fourth 8-Gy fractions given once daily gave TAY = 3.66 +/- 0.22, 2.10 +/- 0.16 and 1.42 +/- 0.17% respectively, an apoptotic response that was significantly decreased compared with the initial 8-Gy fraction (p < or = 0.01). Irrespective of the interfraction interval, two fractions of 8 Gy always induced a greater apoptotic response than that from a single 16 Gy (8 Gy-0 h-8 Gy, p < or = 0.008). TAY from the second 8-Gy dose given at 0, 1, 2, 4, 24 and 48 h was 0.93 +/- 0.03, 2.32 +/- 0.10, 3.26 +/- 0.10, 2.57 +/- 0.11, 3.67 +/- 0.22 and 3.48 +/- 0.13% respectively versus 9.04 +/- 0.34% after the initial 8 Gy (p < or = 0.001). TAY = 7.01 +/- 0.33% from the second 8-Gy dose given at an interval of 3 days was significantly greater than that given at 1 or 2 days (p < 0.0001), but significantly less than that of 9.84 +/- 0.33% given at 14 days (p = 0.0003), suggesting recovery of the apoptotic response occurring at 3 days and completed at 14 days after the initial 8 Gy dose. For radiation-induced apoptosis in the rat spinal cord, we conclude that the concept of equal effect per fraction is not applicable, and that split doses are more effective than the same dose given as a single fraction.

Enhancement of lymphokine-activated killer cell activity by fibronectin

In this study, we demonstrated that immobilized fibronectin (FN) enhanced lymphokine-activated killer cell (LAK) activity, and that the enhanced LAK activity was completely abrogated by an anti-VLA-5 monoclonal antibody and RGD peptide. Fresh spleen cells expressed VLA-4, VLA-6, and vitronectin receptor, whereas VLA-5 was expressed only on the spleen cells activated with interleukin-2. LAK cells showed increased adhesion to immobilized FN compared with that to control bovine serum albumin, and the increased adhesion of LAK cells to immobilized FN was inhibited by anti-VLA-5 monoclonal antibody. Conjugate-formation assay showed that the LAK cells cultured on immobilized FN bound to target cells more efficiently than the control LAK cells, and that anti-LFA-1 monoclonal antibody inhibited the LAK-target cell binding. Immobilized type IV collagen and laminin, as well as FN, enhanced LAK activity. All of these results suggest that the interaction of integrins expressed on LAK cells with extracellular matrix proteins acts in a costimulatory manner for the enhancement of LAK activity, and that anchorage is necessary for full activation of LAK cells.

Distribution of GABAergic and glycinergic premotor neurons projecting to the facial and hypoglossal nuclei in the rat

The distribution of inhibitory premotor neurons for the facial and hypoglossal nuclei was examined in the lower brainstem of the rat. A retrograde axonal tracing method with the fluorescent tracer, tetramethylrhodamine dextran amine (TMR-DA), was combined with immunofluorescence histochemistry for glutamic acid decarboxylase (GAD), i.e., the enzyme involved in gamma-aminobutyric acid synthesis, or glycine. In the rats injected with TMR-DA unilaterally into the facial or hypoglossal nucleus, the distribution of TMR-DA-labeled neurons showing GAD-like immunoreactivity (GAD/TMR-DA neurons) was essentially the same as that of TMR-DA-labeled neurons displaying glycine-like immunoreactivity (Gly/TMR-DA neurons). The distributions of GAD/TMR-DA and Gly/TMR-DA neurons in the rats injected with TMR-DA into the facial nucleus were also similar to those in the rats injected with TMR-DA into the hypoglossal nucleus. These neurons were seen most frequently in the lateral aspect of the pontine reticular formation, the supratrigeminal region, the dorsal aspect of the lateral reticular formation of the medulla oblongata, and the reticular regions around the raphe magnus nucleus and the gigantocellular reticular nucleus pars alpha, bilaterally with a slight dominance on the side ipsilateral to the injection site. A number of GAD/TMR-DA and Gly/TMR-DA neurons were also seen in the oral and interpolar subnuclei of the spinal trigeminal nucleus, bilaterally with a slight ipsilateral dominance. In the rats injected with TMR-DA into the facial nucleus, GAD/TMR-DA and Gly/TMR-DA neurons were also encountered in the paralemniscal zone of the midbrain tegmentum bilaterally with an apparent dominance on the side contralateral to the injection site. A large part of these inhibitory premotor neurons for the facial and hypoglossal nuclei and the excitatory ones may constitute premotor neuron pools common to the orofacial motor nuclei implicated in the control of integrated orofacial movements.

Oligodendrocytes in the adult rat spinal cord undergo radiation-induced apoptosis

Mitotic-linked death is generally regarded as the mode of radiation-induced cell death, particularly in late-responding normal tissues, such as those found in the central nervous system. We have recently reported evidence for radiation-induced apoptosis in the central nervous system using the adult rat spinal cord model. Glial cells, but not neurons or vascular endothelial cells, appeared to undergo apoptosis within 24 h of irradiation. To further characterize the apoptotic process and the type of glial cells involved, a 2-cm segment of the adult rat cervical spinal cord was irradiated with single doses of 1-30 Gy and processed for detailed histological examination at 0, 4, 8, 12, 16, and 24 h after irradiation. Apoptosis was assessed using standard morphological features under the light and electron microscopes and an in situ end labeling assay. A dose response for radiation-induced apoptosis was observed over a dose range of 1-30 Gy, with the peak response at 8 h after irradiation. At 8 h after a 22-Gy irradiation, 96.1% of the apoptotic cells showed positive immunohistochemical staining with Leu-7, a specific marker for oligodendrocytes; only 4.4% of apoptotic cells were positive for Ricinus communis agglutinin-1 (a marker for microglia), and none were positive for glial fibrillary acidic protein (a marker for astrocytes). A significant decrease in the total glial cell density was observed at 24 h after irradiation with 22 (11%) or 30 Gy (14%) but not with 8 Gy. This was due primarily to a decrease in the oligodendroglial density (24%, 22 Gy, P < 0.001; 19%, 30 Gy, P = 0.001), because no decrease in the astroglial population was observed. The duration of apoptosis was estimated to be approximately 1 h. We conclude that there is a depletion of the oligodendroglial population in the adult rat spinal cord within 24 h after irradiation and that the mode of this radiation-induced cell death is apoptosis.

Effects of calcium alginate on cellular wound healing processes modeled in vitro

Although the clinical experience with calcium alginate has been generally good, well-controlled studies examining the effect of such dressings on the processes of wound healing have not been conducted. The healing of cutaneous ulcers requires the development of a vascularized granular tissue bed, filling of large tissue defects by dermal regeneration, and the restoration of a continuous epidermal keratinocyte layer. These processes were modeled in vitro in the present study, utilizing human dermal fibroblast, microvascular endothelial cell (HMEC), and keratinocyte cultures to examine the effect of calcium alginate on the proliferation and motility of these cultures, and the formation of capillarylike structures by HMEC. This study demonstrates that the calcium alginate tested increased the proliferation of fibroblasts but decreased the proliferation of HMEC and keratinocytes. In contrast, the calcium alginate decreased fibroblast motility but had no effect on keratinocyte motility. There was no significant effect of calcium alginate on the formation of capillarylike structures by HMEC. The effects of calcium alginate on cell proliferation and migration may have been mediated by released calcium ions. These results suggest that the calcium alginate tested may improve some cellular aspects of normal wound healing, but not others.

[Protective effect of reduqing injection on rabbits with acute lung injury]

Acute lung injury (ALI) of rabbits was induced by endotoxin and the effects of Reduqing (RDQ) injection on the following indexes were studied. The results showed that the arterial blood pH, PCO2, lung/body index, lung wet/dry weight ratio, the protein and neutrophil contents in bronchoalveolar lavage fluid increased significently together with arterial PO2 marked drop, which were consistent with lung tissue damage, while administration of RDQ simultaneously ameliorated these changes. It is suggested that the Chinese herbal medicine RDQ injection could protect rabbit from the endotoxin-induced ALI.

Endothelium-dependent effect of perindopril and enalaprilat in rat thoracic aorta

AIM

To study the effect of the angiotensin-converting enzyme (ACE) inhibitors perindopril (Per) and enalaprilat (Ena) on the reactivity of the endothelium in normal rats.

METHODS

Male rats were treated intragastrically with Per (2 mg.kg-1.d-1) or placebo (n = 18) for 6 wk. Aorta was isolated for experiment. Another set of isolated aortic rings with and without endothelium were incubated with Ena (0.1 mumol.L-1) for 30 min. Responses to acetylcholine, serotonin, phenylephrine, sodium nitroprusside (SN), and nitroglycerin (Nit) were observed.

RESULTS

Endothelium-dependent relaxation to acetylcholine was augmented in aortic rings from rats treated with Per in comparison with control. The IC50 value (95% confidence limits) decreased from 3.8 (0.56-26.1) mumol.L-1 (control group) to 0.98 (0.28-3.41) mumol.L-1 (Per-treated group). The maximal relaxation was augmented from 62 +/- 9% to 78 +/- 10% (P < 0.01). However, the responses to the endothelium-independent vasodilators, SN and Nit, were similar. Serotonin- and phenylephrine-induced contractions were decreased, which were influenced by basal release of endothelium-derived relaxing factor (EDRF). EC50 values was 6.1 (2.6-14.4) nmol.L-1 vs 8.3 (3.6-18.8) nmol.L-1 in comparison with control group and Per-treated group. The maximal contraction was decreased from 2.42 +/- 0.29 g (control group) to 1.96 +/- 0.25 g (treated group) (P < 0.01). Similar results were found in incubation with Ena.

CONCLUSION

Ena and Per enhanced the basic release of EDRF from vascular endothelium.

The loss of heterozygosity in retinoblastoma and p53 suppressor genes as a prognostic indicator for head and neck cancer

Inactivation of tumor suppressor genes, including p53 and retinoblastoma (Rb), are commonly found in all cancers, including head and neck squamous cell carcinoma. Alterations at either p53 or Rb, however, are only weakly associated with tumor aggressiveness. In many cancers loss of heterozygosity (LOH) at multiple loci is associated with decreased survival. The polymerase chain reaction and highly informative microsatellite markers were used to compare DNA from matched sets of 63 head and neck squamous cell cancers and normal tissue for LOH at the p53 and Rb loci. At p53, 50 were informative, with LOH occurring in 19 (38%). Of the 57 that were informative at Rb, LOH occurred in 21 (37%). Of the 46 that were informative at both p53 and Rb, LOH occurred in 10 (22%) at both loci. When LOH for p53 and Rb individually was compared to stage, differentiation, and survival, there was no correlation. However, the patients with LOH at both loci had a significantly poorer survival (P = .009). This strongly supports the contention that simultaneous alterations of these two tumor suppressor genes favor tumor aggressiveness and can be used as a prognostic indicator.

[Clinical study on combined treatment of shuizhi tuyuan powder and nifedipine in treating hypertension patients complicated with left ventricular hypertrophy]

Patients with essential hypertension complicated with left ventricular hypertrophy (LVH) confirmed by ultrasonic cardiography were divided randomly into observation group and control group. Both groups were treated with nifedipine. Shuizhi Tuyuan Powder (SZTYP, consisted of Hirudo nipponia and Eupolyphaga sinensis) was given in addition to the observation group. The therapeutic course for the two groups were 6 months. Results showed that after one course of treatment, the myocardial weight index lowered from 136.8 +/- 7.5 g/m2 to 130.5 +/- 6.4 g/m2 in observation group, while in control group, it lowered from 136.7 +/- 7.4 g/m2 to 134.3 +/- 6.2 g/m2, the difference between the two groups was significant (P < 0.01). The symptoms were relieved in part of the patients with early stage of cerebrovascular disease treated with SZTYP. The results suggested that SZTYP combined with nifedipine has active curative effect on essential hypertension patients complicated by LVH and part patients in early stage of cerebrovascular disease.

GABAergic and glycinergic neurons projecting to the trigeminal motor nucleus: a double labeling study in the rat

The distribution of GABAergic and glycinergic premotor neurons projecting to the trigeminal motor nucleus (Vm) was examined in the lower brainstem of the rat by a double labeling method combining retrograde axonal tracing with immunofluorescence histochemistry. After injection of the fluorescent retrograde tracer, tetramethylrhodamine dextran amine (TRDA), into the Vm unilaterally, neurons labeled with TRDA were seen ipsilaterally in the mesencephalic trigeminal nucleus, and bilaterally in the parabrachial region, the supratrigeminal and intertrigeminal regions, the reticular formation just medial to the Vm, the principal sensory and spinal trigeminal nuclei, the pontine and medullary reticular formation, especially the parvicellular part of the medullary reticular formation, the alpha part of the gigantocellular reticular nucleus, and the medullary raphe nuclei. Some of these neurons labeled with TRDA were found to display glutamic acid decarboxylase (the enzyme involved in GABA synthesis)-like or glycine-like immunoreactivity. Such double-labeled neurons were seen mainly in the supratrigeminal region, the reticular region adjacent to the medial border of the Vm, and the dorsal part of the lateral reticular formation of the medulla oblongata; a number of them were further scattered in the intertrigeminal region, the alpha part of the gigantocellular reticular nucleus, the nucleus raphe magnus, the principal sensory trigeminal nucleus, and the interpolar subnucleus of the spinal trigeminal nucleus. These neurons were considered to be inhibitory (GABAergic or glycinergic) neurons sending their axons to motoneurons in the Vm, or to local interneurons within and around the Vm.

Enhancement of nondegenerate four-wave mixing based on electromagnetically induced transparency in rubidium atoms

We report an experimental observation of the enhancement of nondegenerate four-wave mixing (NDFWM) based on electromagnetically induced transparency (EIT) in a lambda-type three-level system of rubidium atoms. We measured both the linear susceptibility Im chi(D)((1)) (absorption) and the third-order nonlinear coefficient chi(D)((3)) separately for the NDFWM process at a low atomic density. We found that, owing to the EIT effect, the linear absorption term Im chi(D)((1)) is greatly reduced, while the nonlinear generation term chi(D)((3)) is resonantly enhanced, permitting us to observe a significant enhancement of the NDFWM signal in an optically dense medium.

Defective calcium influx in rat myelomonocytic leukemia cells which are resistant to differentiation-inducing effects of lipid A

We compared the calcium mobilization in parent lipid A-sensitive leukemia cells (P2) and lipid A-resistant cells (LR) after treating them with lipid A in order to clarify the signal transduction involved in the differentiation induced by lipid A. Lipid A induced differentiation in P2 cells; however, LR cells were completely resistant to it. A dramatic elevation of intracellular free calcium ion concentration ([Ca2+]i) occurred in P2 cells, but only a slight elevation of [Ca2+]i in LR cells. Calcium ionophore in combination with lipid A induced differentiation in LR cells. An elevation of [Ca2+]i observed in P2 cells was abrogated by an addition of EGTA, which partially inhibited the differentiation of P2 cells stimulated by lipid A. Altogether, these data indicate that calcium influx is essential for the differentiation of P2 cells stimulated by lipid A and that defective calcium influx is responsible for the resistance to lipid A in LR cells.

Coherent transient amplification in inhomogeneously broadened rubidium atoms by diode-laser frequency switching

We report observation of coherent transient amplification that is due to free-induction decay and optical nutation in inhomogeneously broadened rubidium atoms by a sudden switch of diode-laser frequency. An amplification coefficient of 2.2 x 10(-2) cm(-1) is observed when the diode-laser frequency, initially tuned to the blue side of the Doppler-broadened absorption profile, is switched to be out of resonance by application of a step-function pulsed injection current. The transition from free-induction decay to optical nutation is observed and discussed.

Molecular genetics of malignant insulinoma

Malignant insulinoma is an rare form of cancer with poor prognosis and a reported 5-year survival of 35%. Relatively little is known about the etiology of this disease or of the oncogenes and tumor suppressor genes that participate in its genesis and progression. To address this issue, several protooncogenes, including K-ras, N-ras, erbB-2, erbB-3,c-myc, c-fos, c-jun were examined. Also analyzed was the expression of the growth factors TGF-alpha, EGF, and insulin as well as the EGF receptor (EGF-R), p53 and the putative anti-metastasis gene nm23-H1. These were examined in malignant insulinomas, benign insulinomas, pancreatic B cell hyperplasias and in normal endocrine pancreas. Normal endocrine pancreas showed moderate immunoreaction for c-myc and a strong reaction for insulin. All other parameters were negative. Benign pancreatic B cell hyperplasias were slightly or moderately positive for N-ras and TGF-alpha, and were weakly positive for EGF-R. They were strongly positive for c-myc and insulin. In malignant insulinomas there was strong immunoreaction for c-myc, TGF-alpha, N-ras, K-ras and p53. Insulin reaction was moderate or strong. Molecular genetic studies have been performed for the presence of activating point mutations in codon 12 of the c-K-ras oncogene. Mutations were detected using primer-mediated, mutant-enriched, polymerase chain reaction-restriction fragment length polymorphism analysis and were further characterized by allele-specific oligonucleotide hybridization. Four out of six patients with malignant insulinoma and two out of eight patients with benign insulinoma harbored K-ras point mutations at codon 12. All patients with mutated K-ras oncogene also had elevated levels of p53 protein as well as c-myc and TGF-alpha. In one extremely malignant case we found concomitant mutation at codon 12 of K-ras and codon 61 of the N-ras gene. Our data are consistent with the idea that malignant progression is accompanied by the progressive accumulation of multiple genetic lesions and suggest that activation of myc, TGF-alpha and ras genes may be early events in the development of insulinoma.

The effects of radiation on neovascularization in a rat model

It is thought that radiation treatment inhibits neovascularization of recipient and/or graft tissues, and this may account in part for abnormalities in wound healing associated with radiation therapy. We have examined this hypothesis using a model that measures the neovascularization of an implanted foreign material. Expanded polytetrafluoroethylene (PTFE) sheets were implanted adjacent to both superficial epigastric vascular pedicles of 63 rats distributed into 7 groups (n = 7) that differed with respect to dose and timing of irradiation. Zero to 10 daily fractions of electron-beam radiation (300 cGy each) were delivered to the implant in the right groin, while the implant in the left groin served as a nonirradiated internal control. Unirradiated animals showed equal neovascularization of both implants. Rats that were irradiated twice (single fractions at 0 and 24 hours after implantation) did not show a significant decrease in the neovascularization of the irradiated implant compared with the contralateral control implant. In contrast, the implants that were irradiated three times (single fractions at 0, 24, and 48 hours after implantation) demonstrated significantly diminished ( > 25 percent, p < 0.05) neovascularization beyond day 7, whereas implants irradiated only at 48 hours after implantation did not. Interestingly, neovascularization of the implants irradiated with 10 fractions (3000 cGy) was not significantly decreased compared with irradiation with three fractions (900 cGy). Irradiation delivered before implantation (900 cGy) inhibited neovascularization significantly less than the same dose administered after implantation. The results of this study suggest that a subclinical cumulative dose of 900 cGy is the threshold for impaired tissue revascularization provided that treatment is delivered immediately after implantation over a 48-hour interval.

Central origins of substance P-like immunoreactive fibers and terminals in the spinal trigeminal caudal subnucleus in the rat

After trigeminal rhizotomy, some substance P-like immunoreactive (SP-LI) fibers and terminals in the spinal trigeminal caudal subnucleus (Vc), specially in its superficial laminae (laminae I and II), still remained in the rat. Employing a combination of Fluoro-Gold retrograde tracing and immunofluorescence histochemical staining for SP, we found that the main central origins of these SP-LI fibers and terminals were midbrain periaqueductal gray (PAG), nucleus raphe magnus (NRM) and other raphe nuclei, and nucleus reticularis gigantocellularis pars alpha; all of them are important structures of the endogenous pain control system. The present results provided morphological evidence for PAG or NRM stimulation could inhibit neuronal activities in the Vc evoked by orofacial nociceptive stimulation and also suggested that SP might be an important neurotransmitter or neuromodulator for endogenous pain control system.

Time course of radiation-induced apoptosis in the adult rat spinal cord

Radiation-induced apoptosis has been reported in thymic, lymphoid, haematopoietic cells and intestinal epithelium but is infrequently documented in other adult mammalian cell types. In this study, we examined the time course of radiation-induced apoptosis in the adult cervical rat spinal cord following a single dose of 8 or 22 Gy. Apoptosis was assessed by morphological criteria under light and electron microscopy, and immunohistochemically in-situ using Apoptag to detect 3' -OH ends of DNA fragments. Little evidence of apoptosis (0.3 +/- 0.1 apoptotic nuclei per spinal cord section) was observed in control un-irradiated spinal cord. A significant increase in the number of apoptotic cells per spinal cord section was seen at 4 h after 8 (13.6 +/- 1.3) or 22 Gy (22.0 +/- 2.7). The number of apoptotic nuclei reached a peak at 8 h (44.7 +/- 3.7 after 8 Gy, 49.5 +/- 4.3 after 22 Gy), and returned to the baseline level by 24 h (2.4 +/- 0.7 after 8 Gy, 3.3 +/- 0.7 after 22 Gy). A dose of 22 Gy induced significantly more apoptoses than 8 Gy at 4, 6, 10 and 12 h (P < or = 0.033), but not at 8 h. More apoptotic nuclei were observed in white matter (64-92%) than gray matter (8-36%). All the apoptotic cells were observed in glial cells, and there was no evidence of radiation-induced apoptosis in the vascular endothelial cells or neurons. The morphological features of the apoptotic cells under electron microscopy and the absence of GFAP staining suggested that they were oligodendrocytes. We conclude that radiation induces apoptosis in the adult rat spinal cord, and that the development of apoptosis follows a specific time course.

[Studies on the structure of isoastilbin]

A new compound was isolated from Smilax glabra Roxb., named isoastilbin. It was identified as 5, 7, 3', 5'-tetrahydroxyl-flavanonol-3-O-alpha-L-rhamnopyranoside by means of chemical and spectrometric analysis (UV, IR, 1H-NMR, 13C-NMR, 2DNMR and FAB-MS).

Transient properties of an electromagnetically induced transparency in three-level atoms

We describe the transient behavior of an electromagnetically induced transparency in three-level atomic systems. When the coupling f ield is switched on, the absorption for the probe field is oscillatorily damped to its new steady-state (transparent) value. Transient gain without population inversion and enhancement of dispersion are discussed. A realistic system for experimental testing of these effects is presented.

Superior extension of the parascapular free flap for cervical burn scar contracture

A newly designed superior extension of the parascapular free flap and its free transfer clinically for the repair of 11 cases of cervical burn scar contracture without any loss are presented. The flap sizes ranged from 16 x 7 cm to 32 x 11 cm. Based on the anatomic distribution of the circumflex scapular vessels, the flap in the scapular territory can be taken much longer and wider than before. There is less tension in this vertically oriented flap than in the horizontally oriented flap in obtaining primary closure. This method extends the application of the scapular territory as a donor site for free flaps.

Premotor neurons for trigeminal motor nucleus neurons innervating the jaw-closing and jaw-opening muscles: differential distribution in the lower brainstem of the rat

The distribution of premotor neurons for trigeminal motor nucleus neurons innervating the jaw-closing and jaw-opening muscles was examined in the lower brainstem of the rat by using retrograde and anterograde labeling techniques. First, Fluorogold, a fluorescent retrograde tracer, was injected into the dorsolateral or ventromedial division of the trigeminal motor nucleus, each of which contains motoneurons innervating the jaw-closing or jaw-opening muscles, respectively. Second, Phaseolus vulgaris-leucoagglutinin, an anterograde tracer, was injected into each of the lower brainstem sites, where clusters of retrogradely labeled premotor neurons had been seen in the first set of experiments. Third, after injection of the anterograde tracer into a lower brainstem site, followed by injection of the retrograde tracer cholera toxin B subunit into a masticatory muscle, termination of anterogradely labeled axons onto retrogradely labeled motoneurons was confirmed with the aid of a confocal laser-scanning microscope. It was found that the premotor neurons distributed in the mesencephalic trigeminal nucleus, medial part of the parabrachial region, supratrigeminal region, and dorsal parts of the principal sensory, oral spinal and interpolar spinal trigeminal nuclei project preferentially to the dorsolateral division of the trigeminal motor nucleus, whereas those in the lateral part of the parabrachial region, intermediate parts of the principal sensory, oral spinal and interpolar spinal trigeminal nuclei, and alpha part of the gigantocellular reticular nucleus project preferentially to the ventromedial division of the trigeminal motor nucleus. The dorsal and lateral parts of the medullary reticular formation and the medullary raphe nuclei contain premotor neurons of both types. Group k motoneurons, a cluster of trigeminal motoneurons that innervate the tensor tympani muscle, receive projection fibers predominantly from the dorsolateral part of the oral pontine reticular formation.

Observation of cavity quantum-electrodynamic effects in a Nd:glass microsphere

In a Nd:glass microspherical cavity the enhancement and inhibition of spontaneous-emission processes that are due to cavity QED effects have been observed. The rates of the enhanced spontaneous emission are location dependent and reach a maximum value of more than 10(3) times the free-space value. The large enhancement strongly modifies the decay processes of Nd ions in glass, and the radiative properties of Nd:glass have been changed. As a result a new spectrum including new lasing wavelengths in the Nd:glass sphere has been observed.

A possible role of 92 kDa type IV collagenase in the extramedullary tumor formation in leukemia

Production of metalloproteinases such as collagenases has been reported to be involved in the metastasis of cancer cells. Granulocytic sarcoma in extramedullary sites can be formed by similar steps to other cancers. In this study, we have examined the secretion of type IV collagenases and a tissue inhibitor of metalloproteinase-1 (TIMP-1) in several human leukemia cell lines, including a granulocytic sarcoma-derived cell line established from a patient with granulocytic sarcomas in dermal tissues. We have also examined the invasive capacity of these leukemia cell lines into reconstituted basement membrane, Matrigel, which was used for in vitro invasion assay. Among the human leukemia cell lines used in this study, only the granulocytic sarcoma cell line was found to secrete type IV collagenase constitutively. Other myeloid leukemia cell lines such as HL-60 and U-937 produced type IV collagenase only after treatment with 12-O-tetradecanoylphorbol-13-acetate. All the cell lines secreted similar amounts of the tissue inhibitor of metalloproteinases. In vitro invasion assay revealed that the granulocytic sarcoma cell line showed higher invasive capacity than the other cell lines. These results suggest that the secretion of 92 kDa type IV collagenase plays a role in the leukemia cells' invasion of extramedullary tissues.

The crypt cycle in mouse small intestinal epithelium

We have used a mutation-induced marker system in the intestine of mice heterozygous at the Dlb-1 locus, which determines the expression of binding sites for the lectin Dolichos biflorus agglutinin, and the frequency of clustering of mutated crypts with time as a means of investigating the frequency of the crypt fission process and the crypt cycle. Whole-mount preparations from heterozygous Dlb-1b/Dlb-1a mice were stained with a peroxidase conjugate of Dolichos biflorus agglutinin. Mutations at the Dlb-1b locus in crypt stem cells result in loss of DBA-Px binding in these cells and subsequently their progeny, which eventually results in a rare isolated single, unstained crypt. The subsequent development of pairs, triplets and clusters of negative staining crypts has been assumed to be the result of crypt fission. The frequency of these fission events has been measured in control untreated mice. These negative crypts are the result of spontaneous mutations. We have also looked at mutated crypts after treatment with N-nitroso-N-ethylurea or N-methyl-N'-nitro-N-nitrosoguanidine of young adult mice, which elevates the number of mutations. Our results suggest that the crypt cycle in control animals is very long, 187 +/- 44 weeks (3.6 years, i.e. essentially the life of a laboratory mouse). This implies that about a third of the crypts may divide once in the life of a mouse. After sufficient time for conversion of mixed crypts to monophenotypic crypts after mutagen treatment several clusters of negative crypts were seen.(ABSTRACT TRUNCATED AT 250 WORDS)

[Self-made fibrin sealant administered in thoracic surgery]

From April 1990 to May 1993, 15 patients with thoracic complication or thoracic diseases have been treated with self-made fibrin sealant. All patients have been cured successfully in a short time without thoracotomy. The methods of its make-up, administer and assessment were discussed. It is economical and effective. The major advantage is simple method and easily administered. It could be used in other surgery.

Overexpression of p53 protein is common in premalignant head and neck lesions

In order to determine whether or not the p53 gene is involved in the malignant transformation of the head and neck carcinoma HNSCC, we have analyzed archival specimens from 527 primary head and neck lesions and 27 corresponding lymph node metastases. Nuclear p53 protein was present in 107 of 190 (56%) dysplasias, 61 of 102 (60%) carcinoma in situ (CIS), and 262 of 493 (53%) carcinomas. The p53 score did not increase significantly with progression of these lesions from dysplasia to CIS and to carcinoma. All 357 normal samples of head and neck tissues were negative. The majority of the 172 sets of premalignant and malignant lesions displayed concordant p53 staining patterns. The staining was incongruous in only six cases. The p53 staining results were congruent in all 27 pairs of primary and metastatic (lymph nodes) tumors. These data strongly suggest that p53 protein could be altered in a very early phase of the head and neck tumorigenesis and is maintained during tumor progression and metastatic spread. Mutations in p53 were examined in 11 cases that exhibited high levels of p53 protein as detected by immunohistochemistry using PAb 1801 MAb. Mutation analysis was performed by direct sequencing of the PCR amplification products of exons 5 through 8, which contain greater than 90% of p53 mutations found in tumors. Three of 11 HNSCC had mutations at codon 130 (C to A), 193 (A to T), 283 (G to C), respectively. No mutations were found in the other 8 samples within the regions examined. However, they may have mutations in unsequenced regions of p53 or may have wild type protein that accumulates for other reasons.

The role of the p53 gene in the malignant transformation of pleomorphic adenomas of the parotid gland

Pleomorphic adenoma (PA), the most common neoplasm of the parotid gland in adults, undergoes malignant transformation in only two to six percent of cases. In order to determine whether or not the p53 gene is involved in the malignant transformation of PA of the parotid gland, we have analyzed archival specimens from four patients with carcinoma ex-pleomorphic adenoma (CEPA) by immunohistochemistry and sequencing of the amplified DNA. Tissue specimens from each patient contained both the CEPA and the precursor PA. Immunostaining revealed that while all CEPA were p53 positive, only one of the four precursor PA was positive for p53. In this case, DNA was isolated from both the PA and CEPA and exons five through eight were amplified using the polymerase chain reaction. The same p53 mutation (single base substitution) was found in both the PA and the CEPA at codon 248. Adjacent normal tissue contained the wild-type p53 sequence. To our knowledge, this is the first report of the same p53 point mutation in both a PA and the associated CEPA of the parotid. These results strongly suggest a role for p53 gene mutation in the malignant transformation of some PA of the parotid gland.

[Effect of Saussurea lappa on gastric functions]

The patients with chronic superficial gastritis were selected in the study. The variation in gastric acidity output, serum gastrin and plasma somatostatin concentration were observed during the Saussurea lappa decoction (SLD) perfusion into the stomach. There was no significant changes in acidity output, serum gastrin and plasma somatostatin concentration after the perfusion of SLD (P > 0.05). Changes in gastric emptying and plasma motilin concentration were observed after oral administration of the SLD in 5 healthy volunteers. The time of gastric emptying was markedly shortened after oral administration of SLD (P < 0.01). A significant increase occurred in plasma motilin concentration at 30 min. after oral administration of SLD (P < 0.01). It revealed that SLD could accelerate the gastric emptying and increase the endogenous motilin release.

Parallel studies of clonogenic leukaemia cells and the leukaemia cell population as a whole in acute myelogenous leukaemia

The clonogenic cells in patients with acute myelogenous leukaemia (AML) were evaluated with respect to the relationship between primary and secondary cloning capacity and the proliferative and molecular biological characteristics of the leukaemia cell population as a whole. Secondary cloning capacity was correlated with primary cloning efficiency, and with the ability of the clonogenic cells to produce large sized clones. The cloning capacity of AML cells was unrelated to the cell cycle characteristics of the leukaemia cell population in vivo or to the level of myc, myb, fms, or interleukin (IL)1 beta expression. The sensitivities of the clonogenic cells to cytosine arabinoside and daunorubicin were inversely correlated with the ability of the leukaemia cells to produce large sized clones in vitro. This latter observation may explain the reported relationships between the clonogenic capacity of AML cells and response to chemotherapy.

Retrieval of p53 protein in paraffin-embedded head and neck tumor tissues

OBJECTIVES

To improve the detection of p53 protein in formalin-fixed, paraffin-embedded head and neck tumor tissues.

DESIGN

Cohort.

SETTING

University and Veterans Administration medical centers.

PATIENTS OR OTHER PARTICIPANTS

Retrospective samples.

INTERVENTION

Surgery for head and neck carcinoma.

MAIN OUTCOME MEASURES

Retrieval of p53 antigen. Hypothesis formulated after data collection.

RESULTS

An antigen retrieval method facilitated the unmasking of previously inaccessible p53 antigenic determinants in formalin-fixed, paraffin-embedded tissues. This approach has made possible a much more reliable and sensitive immunohistochemical detection of p53 antigen. The procedure is simple, requiring only microwave heating of tissue sections to 100 degrees C in the presence of a zinc sulfate solution.

CONCLUSIONS

Antigen retrieval method in formalin-fixed, paraffin-embedded tissue demonstrated a significant increase in p53 immunostaining.