Platelet adhesion receptors

The response to vascular injury involves attachment and aggregation of platelets, coupled with initiation of the coagulation cascade. These inter-related processes ensure that the vessel injury is rapidly blocked with an aggregated clump of platelets that is then stabilized by a crosslinked fibrin matrix. Initial adherence relies on the ability of the platelet adhesion receptors to bind subendothelial matrix molecules. Platelet activation then results in the expression of high affinity integrin receptors on the cell surface that bind soluble ligands, allowing platelets to aggregate and form a haemostatic plug.

[An analysis of pathologic features and prognostic factors of 10 cases with pseudomyxoma peritonei]

OBJECTIVE

To investigate the histogenesis and the pathological features of pseudomyxoma peritonei and to analysis its prognostic factors.

METHODS

Ten cases with pseudomyxoma peritonei were clinicopathologically studies, with follown-up at least 24 monthes. All histopathological sections and clinical data were reviewed.

RESULTS

Seven out of 10 patients had the ovarian mucinous tumors which were bilateral in 5 cases (71.4%). Histopathologically, 4 of 7 cases with ovarian tumor were characterized by the presence of the multifocal bleeding, fragmental necrosis, and occasionally, the striated border on the glandular lumens. The mucinous epithelial cells and mucin invased into the peritonei, destroyed normal structure, and formed the desmoplasia. Four patients died of pseudomyxoma peritonei, all with extensive lesions, invasions in the peritonei, and a short recurrent time (mean, 12.0 monthes) after presentation.

CONCLUSIONS

The histogenesis of pseudomyxoma peritonei is heterogenous, the presence of possible metastases including from the appendix, the colon and other organs. The most important factors of the prognosis should include the extent of initial lesions, the presence of invasion in the peritonei and a rapid recurrence.

Synergy between growth factors and transmitters required for catecholamine differentiation in brain neurons

The phenotypically plastic neurons of the embryonic mouse striatum were used to explore mechanisms of catecholamine differentiation in culture. De novo transcription and translation of the CA biosynthetic enzyme, tyrosine hydroxylase (TH), was induced in striatal neurons exposed, simultaneously or sequentially, to the growth factor, acidic fibroblast growth factor (aFGF) and a catecholamine. Although dopamine was the most potent aFGF partner (ED50 = 4 microM), a number of substances, including dopamine (D1) receptor agonists, beta-adrenoceptor agonists, and dopamine uptake inhibitors also trigger TH induction when accompanied by aFGF. However, since none of the receptor antagonists nor transport blockers tested could inhibit dopamine's action, the mechanism remains obscure. Structure-activity analysis suggests that effective aFGF partners all contain an amine group separated from a catechol nucleus by two carbons. Thus, TH expression can be novelly induced by the synergistic interaction of aFGF, and to a lesser extent basic FGF, and a variety of CA-containing partner molecules. We speculate that a similar association between growth factor and transmitter may be required in development for the differentiation of a CA phenotype in brain neurons.

Brain-derived neurotrophic factor works coordinately with partner molecules to initiate tyrosine hydroxylase expression in striatal neurons

Previous studies demonstrated that the cooperative interaction of acidic fibroblast growth factor (aFGF) and a partner molecule could induce the novel expression of the catecholamine (CA) biosynthetic enzyme, tyrosine hydroxylase (TH) in striatal neurons [Du and Iacovitti, J. Neurosci., in press; Du et al., J. Neurosci., 14 (1994) 7688-7694; Iacovitti et al., submitted]. The present study demonstrates that in addition to aFGF, brain-derived neurotrophic factor (BDNF) is also capable of moderate levels of TH induction (30% TH+ striatal neurons) when administered at high concentrations (100 ng/ml). As with aFGF, BDNF's activity depended on its coupling to an appropriate partner molecule; the most potent of which were 10 microM dopamine (DA) and 50 microM mazindol. BDNF + DA-induced TH expression was first evident after at 12 h; peaked by 18 h and declined by 4 days in culture. Cyclohexamide eliminated nearly all and alpha-amanitin reduced by half the TH induction elicited by DA and BDNF; indicating that both de novo transcription and translation were required for increased expression. In contrast with aFGF and BDNF, other putative dopamine differentiation factors, such as glial-derived neurotrophic factor (GDNF) and ciliary neurotrophic factor (CNTF), were able to elicit barely detectable (10%) levels of TH induction, regardless of the partner molecule used. These studies suggest that aFGF and/or BDNF may work coordinately with partner molecules to initiate TH expression; while a number of factors including, CNTF and GDNF, may be involved in its subsequent modulation.

Update on development of interleukin-11

This paper reviews the recent studies of interleukin-11 gene expression and regulation, receptor and signal transduction, pharmacologic effects, and preclinical and clinical studies. Interleukin-11 is expressed in cells of mesenchymal origin and gene expression can be modulated by several inflammatory cytokines and agonists. The signaling pathways involved in cytokine induction of interleukin-11 gene expression vary between cell types. In vitro and in vivo studies reveal that interleukin-11 displays a wide spectrum of bioactivities including responses in hematopoietic and nonhematopoietic cells. Preclinical studies in animal models suggest that interleukin-11 may be useful in acceleration of the recoveries of both hematopoietic cells and gastrointestinal mucosal cells after cytoablative therapies. Several clinical studies have demonstrated interleukin-11 to be well tolerated and suggest interleukin-11 is a promising cytokine to prevent both neutropenia and thrombocytopenia in patients with cancer who are receiving chemotherapy.

Differences in colorectal cancer between China and Japan: a clinical and histological study of two groups of cases

It is well known that most tumours are attributed to life style, especially the tumours of the digestive system. Clinical and histopathological investigation of tumours in different human groups and societies, and analysis of the variations will provide evidence for this, and is one of the approaches to study carcinogens. Clinical data obtained from 391 patients with colorectal cancer at the Sakai Municipal Hospital, Japan, and Shanghai Jinshan Hospital and Cancer Hospital, China, from 1987 to 1992, included the sex, age and tumour subsite. Sections of histological specimens were also retrieved. The results were compared between two countries. The average age of patients with colorectal cancer in Shanghai was 8.5 years less than in the Sakai group. The age peak of the former was 51-60, and in the latter, 61-70 years. The most frequent site of the cancer in the Shanghai group was the rectum, contrasting with the higher percentage of sigmoid colon cancer in Sakai group. There was also a significant difference in histological subtype of the cancer between the two groups. Mucinous adenocarcinoma was notably more common in the Shanghai group than in the Sakai group, and the high frequency was mainly in the colon. All of the variations were suggested to be attributable to differing socioeconomic circumstances and lifestyle, especially the dietary habits of the countries.

Mouse model of X-linked chronic granulomatous disease, an inherited defect in phagocyte superoxide production

Chronic granulomatous disease (CGD) is a recessive disorder characterized by a defective phagocyte respiratory burst oxidase, life-threatening pyogenic infections and inflammatory granulomas. Gene targeting was used to generate mice with a null allele of the gene involved in X-linked CGD, which encodes the 91 kD subunit of the oxidase cytochrome b. Affected hemizygous male mice lacked phagocyte superoxide production, manifested an increased susceptibility to infection with Staphylococcus aureus and Aspergillus fumigatus and had an altered inflammatory response in thioglycollate peritonitis. This animal model should aid in developing new treatments for CGD and in evaluating the role of phagocyte-derived oxidants in inflammation.

Novel expression of the tyrosine hydroxylase gene requires both acidic fibroblast growth factor and an activator

Substances found in the soluble extract of muscle can alter the differentiative fate of certain brain neurons in culture by triggering novel expression of the gene for the catecholamine biosynthetic enzyme tyrosine hydroxylase (TH) (Iacovitti et al., 1989; Iacovitt, 1991). In this study, we demonstrate that TH induction in cultured noncatecholamine neurons from the mouse striatum requires the cooperative interaction of at least two substances found in muscle. Purification studies, combined with biological assay, revealed that one necessary component is acidic fibroblast growth factor (aFGF), and the other, an unidentified molecule(s) of < 10 kDa molecular weight that activated aFGF. Thus, muscle-derived aFGF, if incubated in the presence but not the absence of the < 10 kDa fraction of muscle, induced a dose-dependent increase in the number of striatal neurons that novelly express TH. This expression was blocked by prior incubation and protein A precipitation of the factor with polyclonal antibodies to aFGF (1:200-1:1000). Similar to muscle-purified aFGF, commercial preparations of native bovine and human recombinant aFGF (0.1-100 ng/ml) were potent inducers of TH when coincubated with the < 10 kDa activator. In contrast, basic FGF produced little and FGF-7 no induction of TH. Unlike the unidentified activating agent in muscle, heparin (20-500 mU), a known activator of aFGF, did not potentiate the factor's TH-inducing activity. Nonetheless, heparatinase (100 mU) prevented TH induction by aFGF and its activator, indicating that binding of heparan sulfated proteoglycans is necessary for the effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Association of a phospholipase A2 (14-3-3 protein) with the platelet glycoprotein Ib-IX complex

Platelet adhesion to subendothelial von Willebrand factor involves receptor recognition by the platelet glycoprotein (GP) Ib-IX and initiates activation signals that contribute to primary hemostasis. We show here that GPIb-IX is specifically associated with an intracellular 29-kDa protein. The physicochemical characteristics and amino acid sequence of this protein indicate that it is identical to the human zeta-isoform 14-3-3 protein, previously characterized as a platelet phospholipase A2 (PLA2). As activation of PLA2 is an early event in GPIb-IX-mediated signaling, this result suggests that ligand occupancy of GPIb-IX may directly activate PLA2, leading to platelet activation.

Allelotype study of esophageal carcinoma

To investigate genetic features of esophageal cancer, we have examined 93 squamous cell carcinomas of the esophagus for loss of heterozygosity (LOH), using 41 restriction fragment length polymorphism (RFLP) markers representing all autosomal chromosomes. Allelic losses at frequencies of at least 30% were observed at loci on chromosomal arms 3p (35%), 3q (30%), 5q (36%), 9p (57%), 9q (60%), 10p (33%), 13q (43%), 17p (62%), 17q (46%), 18q (38%), 19q (32%), and 21q (37%). These results suggest that several putative tumor suppressor genes, in addition to the cyclin D and TP53 genes that are sometimes mutated in esophageal carcinomas, may be associated with development and/or progression of esophageal cancer. By a comparison of LOH on each chromosomal arm with clinicopathological parameters, we have found a significant correlation between LOH on 19q and regional lymph node metastases. Interestingly, the frequency of LOH on 17q was significantly higher in tumors in female patients (12 of 14 cases) than in those in male patients (20 of 56 cases) (P = 0.0009 by Fisher's exact test). Furthermore, we examined for mutations of the APC gene on chromosome arm 5q. Screening of nearly one third of the APC coding region, including the MCR (mutation cluster region), revealed no alterations. Therefore, although allelic loss at the APC locus is frequent in squamous cell carcinomas of the esophagus, it is likely that a gene on 5q other than APC is involved in esophageal tumorigenesis.

Frequent loss of heterozygosity in the region including BRCA1 on chromosome 17q in squamous cell carcinomas of the esophagus

Ninety-four esophageal squamous cell carcinomas were examined for loss of heterozygosity at several loci on the long arm of chromosome 17 (17q), using restriction fragment length polymorphism markers. Loss of heterozygosity was observed in 56 (62%) of 91 tumors that were informative with at least one marker. Comparison of these results with clinicopathological data indicated that the losses on chromosome 17q had occurred at an early stage of carcinogenesis. Detailed deletion mapping in these tumors revealed that the region commonly deleted was within the segment between loci defined by two markers at chromosomal band 17q21.3.

Measuring outcomes in care of the elderly

This observational study was designed to assess whether routine measurement of outcomes using standard instruments is possible as part of clinical routine in care of the elderly, and to establish if such instruments are responsive to clinical change. Indices of functional status, cognitive function and subjective health status were collected routinely on admission and discharge in 540 inpatients and 340 patients attending a day hospital. Data collection became integrated into clinical routine. Response rates were generally good and yielded acceptably complete data. For inpatients, outcome was reflected by measurement of survival, physical function (Barthel index) and social status, each of these indicators showing significant change between admission and discharge. For day hospital patients, neither these, nor the Nottingham ADL scale, nor a health status indicator proved sufficiently responsive to clinical change to merit recommendation as outcome indicators for routine use in older patients. In ambulatory care in older patients, such as those attending a day hospital, new approaches are needed to measure clinical outcomes.

Long range propagation of conformational changes in integrin alpha IIb beta 3

Integrin adhesion receptors participate in two-way transfer of information across the plasma membrane. For example, cytoplasmic events, such as activation of protein kinase C, cause an increase in the fibrinogen (Fg) binding affinity of the extracellular domain of integrin alpha IIb beta 3 ("inside-out signaling"). Conversely, ligand binding to alpha IIb beta 3 results in the generation of intracellular signals. We used anti-LIBS2, an anti-beta 3 monoclonal antibody, to understand potential mechanisms of this bidirectional signaling. Anti-LIBS2 bound to alpha IIb beta 3 with low affinity (Kd = 7.4 microM), and mimicked inside-out signaling by promoting Fg binding. The affinity of anti-LIBS2 binding was increased 20-fold (Kd = 326 nM) by addition of an Fg-mimetic synthetic peptide, RGDS. Thus, anti-LIBS2 and ligands (Fg and Fg-mimetic peptides) bind cooperatively to integrin alpha IIb beta 3, indicating a functional linkage between the ligand-binding site and the antibody-binding site. The anti-LIBS2-binding site was mapped by its binding to proteolytic and recombinant fragments of the beta 3 subunit. The epitope was located within an 89-residue region immediately adjacent to the transmembrane domain and 400 residues carboxyl-terminal to the known ligand-binding site(s). Electron microscope images of rotary shadowed ternary complexes of Fg, anti-LIBS2, and alpha IIb beta 3 revealed that the ligand-binding site and anti-LIBS2 epitope are separated by about 16 nm. This indicates that propagated long distance conformational changes can occur in alpha IIb beta 3. Such changes are likely to be involved in the bidirectional signaling function of this integral membrane protein.

Protective effects of berberine and phentolamine on myocardial reoxygenation damage

The protective effects of berberine and phentolamine against anoxia and reoxygenation damage in isolated rat hearts have been investigated. Incorporation of berberine (24.5 mumol/L) in both anoxic and aerobic perfusion media resulted in a significant reduction of CPK release during the reoxygenation period, and the ultrastructural damage was reduced as compared with the control group; the myocytes in the berberine-treated group displayed mild intracellular edema, well-registered myofibrils without contracted bands, and swollen mitochondria with partially broken cristae but without dense bodies. Berberine did not inhibit calcium and sodium accumulation or magnesium and potassium loss. Treatment with phentolamine (6.6 mumol/L), an alpha-adrenoceptor antagonist, had similar effects, though the CPK release profile was shifted to the right and downwards. These results suggest that although berberine and phentolamine have some beneficial effects on myocardial reoxygenation injury, they may not abolish the injury. Therefore alpha-adrenoceptor stimulation may not be the major mechanism behind the injury.

[Synchronized control of specific gravity, drug contents and recovery rate of inspissated extracts]

As a result of experimentation we have developed a method that helps to synchronize the control of the three preset criteria, i.e. specific gravity, drug contents and recovery rate, in the process of preparing traditional Chinese medicines. Simple and easy to use, the method is also good for similar purposes in the preparation of traditional Chinese syrups.

Inside-out integrin signalling

Integrins are expressed by virtually all cells and play key roles in a range of cellular processes. Changes in the integrin surface repertoire provide a means of altering the strength and ligand preferences of cell adhesion. Recent research has examined the affinity modulation of integrins, a rapid and versatile mechanism of cell adhesion regulation. Studies with a prototype, alpha IIb beta 3, indicate that intracellular events influence the conformation and ligand-binding affinity of the extracellular domain of integrins. This 'inside-out' signal transduction appears to be mediated through the integrin cytoplasmic domains. In addition, in some cases affinity modulation of integrins may be cell-type specific. The clarification of the mechanisms of integrin affinity modulation should help explain rapid changes in cell adhesion that occur during cell migration, aggregation and the cell cycle.

[A histochemical study of saikosaponins]

The root of Bupleurum chinese and B.scorzonerifolium was examined histochemically in order to clarify the distribution of saikosaponins in various tissues and parts of the root. By means of qualitative and quantitative analyses, saikosaponins, the bioactive principles in the root, were found to be abundant in the cortex outside the cambium and very little in the xylem of the root. It was also found that the thinner root hairs had the highest contents of saikosaponins, but decreased towards the thicker root head.

[Effect on anti-aging and treating yang deficiency of kidney with huanshao dan capsules. A clinical report of 309 cases]

In this study, with various dosages of huanshao dan capsules, an old Chinese medicine formula, the authors treated the patients with Yang-deficiency of kidney for 1.5-3 months and compared the effects of huanshao dan with those of watered pills and placebo. The analyses of Ridit's showed not only the scores of symptoms of the great-dose huanshao dan group (group 2), the great-dose watered pill group (group 3), the small-dose watered pill group (group 4) and but even the short-treating course group (group 5) were remarkably improved after treatment (P less than 0.001, P less than 0.01); but the group 6 have not any difference after treatment. However, the functions of liver and kidney, the level of cholesterol, the concentration of blood sugar, blood pressure and heart rate remained the same after treatment. The scores of the ability of prompt memory as well as serum lipid peroxide, serum adrenocortical hormone, cellular immunological function, index of glycoprotein and T3, T4 had similar changes. Our data suggested that both huanshao dan and watered pills were beneficial for anti-aging process and there was no noticeable difference between the two drugs.

[Dynamic variation of saikosaponin contents]

In this paper both the cultivated and wild Bupleurum chinense and B. scorzonerifolium from northeast China of different growing periods and ages were analyzed for the contents of saikosaponins a and d by HPLC and total saikosaponins by spectrophotometry. The results indicated that the saikosaponin content of B. chinense was higher than that of B. scorzonerifolium, and that the saikosaponin contents of the cultivated species were higher than or almost equal to those of the wild ones. It was also found that both the cultivated and wild B. chinense and B. scorzonerifolium featured the highest contents of saikosaponins in the nutrition-growing period.

The reaction of singlet oxygen with proteins, with special reference to crystallins

Photosensitized oxidation of the eye lens proteins, the crystallins, is thought to lead to protein crosslinks and high molecular weight aggregates. Such protein modifications may be important factors in the formation of lens opacities or cataracts. We focus attention here on type 2 photo-oxidation involving the reaction of singlet oxygen (1O2) with crystallins and some "control" proteins. We find that: (1) trp residues are oxidized to N-formyl kynurenine and related products, but this in itself does not lead to the production of high molecular weight protein aggregates of the protein; (2) tyr residues react with 1O2 but we do not detect dihydroxyphenylalanine or bityrosine nor are protein crosslinks formed as a result; (3) oxidation of his residues appears necessary for high molecular weight protein covalent aggregates to form. Proteins devoid of his, e.g. melittin or bovine pancreatic trypsin inhibitor, do not form high molecular weight products upon reaction with 1O2. Prior reaction and blocking of his inhibits the crosslinking reactions. (4) The oxidized protein is seen to be more acidic than the parent and has an altered tertiary structure. (5) Among the crystallins, reactivity towards 1O2 varies in the order gamma greater than beta greater than alpha and also gamma A/E greater than gamma D greater than gamma B crystallin.

[Damage to cochleae in newborn guinea pigs by 80dB white noise]

Two groups of guinea pigs (the newborn and the adult) were exposed to 80dB SPL white noise for 72 hours. The effects were observed with E CochG, surface preparation, scanning electron microscopy and histochemical techniques. The results showed that: 1. the response threshold of the newborn was elevated after exposure; 2. the rate of OHC loss was higher in cochleas of the newborn than those of the adult; 3. OHC damage was mainly found in the fourth turn of cochlea of the newborn; 4. the LDH activity decreased in the newborn. It seems that the white noise could damage the hair cell function and structure in the newborn guinea pigs which are more susceptible to noise than the adult ones. The different susceptibility might be related to the degree of development and maturity of the cochleas.

Glycoprotein Ib and glycoprotein IX are fully complexed in the intact platelet membrane

Two new murine monoclonal antibodies, AK 1 and SZ 1, reactive with the human platelet glycoprotein (GP) Ib-IX complex have been produced by the hybridoma technique. Both AK 1 and SZ 1 immunoprecipitated the GP Ib-IX complex from Triton X-100-solubilized, periodate-labeled platelets. With trypsinized, labeled platelets, AK 1, SZ 1, and FMC 25 (epitope on GP IX) immunoprecipitated a membrane-bound proteolytic fragment of the GP Ib-IX complex consisting of GP IX and an congruent to 25,000 mol wt remnant of the alpha-chain of GP lb disulfide-linked to the beta-subunit. Unexpectedly, although AK 1 and SZ 1 immunoprecipitated purified GP Ib-IX complex, neither antibody immunoprecipitated the individual components of this complex, GP Ib or GP IX. When GP Ib and GP IX were recombined, however, AK 1 and SZ 1 again immunoprecipitated the reformed complex, strongly suggesting that both antibodies were recognizing an epitope present only on the intact complex. Cross-blocking studies indicated that AK 1 and SZ 1 recognized a very similar or identical epitope that was proximal to the epitope for FMC 25. Both AK 1 and SZ 1 bound to a similar number of binding sites (congruent to 25,000) on intact platelets as monoclonal antibodies directed against either GP lb or GP IX. The combined data suggests that GP lb and GP IX are fully complexed in the intact platelet membrane.