Development of magnetic beads for rapid and efficient metal-chelate affinity purifications

Metal-chelate affinity chromatography offers multiple advantages for protein purification, yet existing resins make its applications to sparse, hydrophobic, or particularly labile proteins and peptides quite difficult. In this work, we have developed a simple method to covalently modify commercially available superparamagnetic beads with a six-carbon spacer and nitrilotriacetic acid to provide a novel resin for extremely rapid and efficient metal chelate affinity purifications. Further, the small size and surface chemistry of these beads provide clear improvement in applicability to small scale purifications with reduced nonspecific adsorption. These advantages have been demonstrated relative to a commercially available nickel resin.

[Clinical analysis of surgical treatment for 86 patients with localized small-cell lung cancer]

To assess the value of surgical treatment followed by adjuvant chemotherapy for localized small-cell lung cancer (SCLC), the results of treatment in 86 SCLC patients since 1990 were reviewed. Of 86 patients, 19 patients received pneumonectomy, 53 lobectomy, 6 wedge resection and 8 segmental resection. Postoperative pathologic staging revealed 24 in stage I, 36 in stage II, and 26 in stage III. Postoperative adjuvant chemotherapy was given in 78 patients. Until the latest follow-up, 28 patients remained alive and 58 patients died. The 5-year survival rate of the 86 patients was 37%. The survival of patients in stage I was better than that of patients in stage II (P = 0.018) and stage III (P = 0.021), but the survival of patients in stage II was not significantly different from that of patients in stage III (P = 0.234). In summary, surgical treatment followed by chemotherapy improves significantly the survival of patients with localized SCLC. TNM staging is of prognostic importance.

Partial ablation of the neonatal external granular layer disrupts mossy fiber topography in the adult rat cerebellum

The spinocerebellar projection in the rat is compartmentalized in an array of parasagittal bands of mossy fiber terminals. These bands align reproducibly with bands of Purkinje cells that differentially express zebrin II. To investigate whether this alignment is obligatory, Purkinje cell and mossy fiber compartmentation has been compared in the rat cerebellum where the cytoarchitecture was contorted by neonatal administration of methylazoxymethanol. Methylazoxymethanol ablates many granule cell precursors, leaving a much reduced external granular layer, and adult rats that received a single methylazoxymethanol injection at birth showed varying degrees of abnormal cerebellar foliation. Zebrin II immunocytochemistry nevertheless revealed no fundamental abnormality in the Purkinje cell compartments. However, despite the normal Purkinje cell compartmentation being retained, the spinocerebellar mossy fiber-Purkinje cell topography is disrupted by methylazoxymethanol treatment. The normal precise array of parasagittal mossy fiber terminal fields becomes blurred across the lobule, and the normal clear banding is difficult to follow. These data suggest that, despite the early topography being dependent on the Purkinje cells, the granule cell-mossy fiber interactions also regulate the topography of the spinocerebellar projection.

[Relationship between the state of intravascular bubbles and microcirculation system]

To confirm the hypothesis that air bubbles were unable to block the blood vessels and that the state of the intravascular bubbles was determined by the function of the circulatory system, 35 guinea pigs were pressurized then were decompressed to normal pressure. Microscopic observation was made of the bulbar conjunctival, dorsum auricular and subcutaneous vessels in 33 surviving animals. Air bubbles of different amounts, sizes and shapes were found in the dorsum auricular and subcutaneous vein of all the amimals and in the bulbar conjunctival oriridal artery of 16 animals, and in some cases the vessels were even filled with bubbles. The bubbles ran in the same direction and at the same speed as the blood flow. They could run in a backward, to-and-fro or sluggish flow. The bubbles looked shapeless and tended to break and divided into branch flows where the vessel branches. The bubbles were motionless at the proximal end of the artery occluded due to spasm or when the blood was stagnated. Under the action of the blood pressure the bubbles could expand the vessel and push forward. The bubbles showed a tendency of flowing with ease with the function of the vessel recovered. The results suggest that bubbles of any size in the vessel could easily change their shape under the action of the blood flow and pressure, and pass through vessels of any diameter and circulate with the blood. Only when a vessel was occluded due to spasm or the blood in a vessel was stagnated could the bubbles be motionless, but it was not that the bubbles blocked the vessel.

Transforming growth factor beta-1 and beta-2 in human tear fluid

PURPOSE

To evaluate human tear fluid for transforming growth factor beta isoforms 1 and 2 (TGF-beta1 and TGF-beta2).

METHODS

To accomplish this, human tears were evaluated for TGF-betas by quantitative antibody sandwich ELISA (sELISA), mink lung epithelial cell (MLEC) growth inhibition bioassay and western blotting. Various physical and chemical treatments were used to activate TGF-beta in these assays.

RESULTS

TGF-betas could not be detected in untreated or heated tears by sELISA; however, mean TGF-beta1 concentrations of 2.32 ng/ml were detected in acid-activated tears by sELISA. Furthermore, 10.54 ng/ml of TGF-beta1 and 2.98 ng/ml of TGF-beta2 were detected in tears treated with the mucolytic agent, acetylcysteine. Total TGF-beta bioactivity in human tears measured by the MLEC assay was found to be 13.04 ng/ml in untreated tears and 24.85 ng/ml in acid-activated tears. Approximately one-half TGF-beta in tear specimens was biologically active (mean = 52%, range 39-71%). Total tear TGF-beta bioactivity could be completely neutralized by recombinant human TGF-beta1 latency associated peptide (rh TGF-beta1 LAP). Mean neutralization of tear TF-beta bioactivity was 83% by TGF-beta1-specific antisera, and was 13% by TBF-beta2-specific antisera. Immunoreactive TBF-beta bands at approximately 12.5 and 95 kD were observed in immunoblots of reduced acidified tears. A high molecular weight (MW) TGF-beta band (>203 dD) was noted in untreated tears; however, this band disappeared following treatment with acetylcysteine.

CONCLUSIONS

The results of these studies indicate that TGF-beta1 and TGF-beta2 are present in human tear fluid, and TGF-beta1 is the predominant isoform. There appear to be factors in human tears capable of binding TGF-beta.

Production and secretion of transforming growth factor beta (TGF-beta) by the human lacrimal gland

PURPOSE

Transforming growth factor beta (TGF-beta) isoforms 1 and 2 have recently been detected in stimulated human tear fluid. The purpose of this study was to determine if these TGF-sbeta are produced and secreted by the lacrimal gland.

METHODS

To accomplish this, reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect expression of TGF-beta1 and TGF-beta2 mRNAs in normal human and rabbit lacrimal gland biopsies. Northern blot analyses were used for comparing the relative levels of expression of these TGF-beta mRNAs in rabbit lacrimal glands. Human lacrimal gland biopsies were evaluated by immunohistochemistry for production of TGF-beta1, TGF-beta1 latency associated peptide (LAP), and TGF-beta2 proteins. Supernatants of unstimulated and carbachol-stimulated human lacrimal gland explant cultures were evaluated for secretion of TGF-beta1 and TGF-beta2 by ELISA:

RESULTS

TGF-beta1 and TGF-beta2 mRNA expression was found in all human and rabbit lacrimal gland specimens by RT-PCR. A greater level of expression of TGF-beta1 than TGF-beta2 mRNA in the rabbit lacrimal gland was noted by Northern blot. In human lacrimal gland biopsies, TGF-beta1 and TGF-beta1 LAP were detected in acinar and ductal epithelia by immunohistochemistry. TGF-beta2 specific antibodies stained a small percentage of acinar and ductal epithelia, as well as material within the lumens of tubulo-acinar complexes in one-third of these glands. TGF-beta1 was detected in supernatants of human lacrimal gland explants, and the concentration of TGF-beta1 increased by an average of 280% after carbachol-stimulation (p = 0.004). TGF-beta2 could not be detected in unstimulated or stimulated human lacrimal gland supernatants.

CONCLUSIONS

The results of these experiments indicate that TGF-beta1 and TGF-beta2 are produced by and TGF-beta1 is secreted by the human lacrimal gland. They also suggest that the lacrimal gland may be one source of TGF-beta in human tear fluid.

Activities of novel nonglycosidic epipodophyllotoxins in etoposide-sensitive and -resistant variants of human KB cells, P-388 cells, and in vivo multidrug-resistant murine leukemia cells

Previous structure-activity studies of the antitumor compound etoposide (VP-16) have suggested that replacement of the glycoside moiety could afford therapeutically active analogues with different biochemical determinants for cellular accumulation and drug resistance. In the present report, 10 analogues of VP-16 in which the glycosidyl moiety was replaced with alkyl or arylamino substituents exhibited 5-10-fold better binding affinity for topoisomerase II/DNA complex in human KB cells. A similar increase in the binding affinity was observed in an isolated-nuclei model. The analogues displayed greater or comparable potency to VP-16 in cell growth-inhibition studies and were less affected by cell membrane-associated drug resistance mechanisms, as exemplified by overexpressions of P-glycoprotein multidrug-resistance gene or multidrug resistance-associated protein. Interestingly, in animal studies, analogues least affected by the membrane transport-deficiency phenotypes exhibited low therapeutic index values, thus suggesting that highly efficient modulation of cellular membrane transport defects could perturb the selectivity of antitumor agents for cancer cells. This report also suggests a new method of quantifying drug-induced protein-linked DNA breaks by graphically determining the apparent dissociation-inhibition constant (Kdi) for the inhibitors.

Synthesis and cytotoxic activities of the amine-exchange products of 2-dimethylaminomethyl-5-(E)-substituted arylidene cyclopentanones with anilines: 2-arylaminomethyl-5-(E)-arylidene cyclopentanones

A series of 2-arylaminomethyl, and 2-(4-morpholinylmethyl)-5-(E)-arylidene cyclopentanones have been synthesized via an amine-exchange reaction. Most of the compounds showed significant cytotoxic activities, in vitro, on various human cancer cell lines. Generally, compounds with a para-chloroanilino moiety were more active than those of other aniline derivatives. No apparent changes were observed by altering the substituents on the arylidene portion. For the majority of active compounds, leukemia is one of the most sensitive subpanels at both GI50 and TGI levels but the least sensitive one at the LC50 level. Colon cancer is one of the most sensitive subpanels in all three levels. COMPARE results indicated that the characteristics, and possibly the mechanism of the cytotoxic properties of the 2-arylaminomethyl derivatives might be different from that of the 2-dialkylaminomethyl derivatives previously reported.

Developing mossy fiber terminal fields in the rat cerebellar cortex may segregate because of Purkinje cell compartmentation and not competition

Many mossy fiber afferent projections to the rat cerebellar cortex terminate in parasagittal bands. In particular, the anterior lobe vermis of the cerebellum contains alternating bands of mossy fibers from the spinal cord and external cuneate nuclei. The cerebellar cortical efferents, the Purkinje cells, are also organized in parasagittal bands. These can be revealed by immunochemical staining for the antigen zebrin II, which is selectively expressed by bands of Purkinje cells. In some cases, the boundaries between mossy fiber terminal fields align with identified transitions between zebrin+/- sets of Purkinje cells, whereas others are located within apparently homogeneous Purkinje cell compartments. Two theories can explain the terminal-field topography: In one view, mossy fiber terminals segregate during development, because growth cones from different sources compete for common territory. Alternatively, mossy fiber growth cones directly recognize chemically distinct target territories, and activity-dependent mechanisms play only minor roles. To explore these issues, two sets of experiments were performed. First, the terminal-field map of the neonatal spinocerebellar projection was compared to the Purkinje cell compartmentation as revealed by anticalbindin immunocytochemistry. Second, subsets of spinocerebellar mossy fiber afferents were ablated early in postnatal development, and the consequences for the neighboring cuneocerebellar terminal fields were mapped in the adult with reference to the zebrin II+/- compartments. These experiments revealed no evidence that competitive interactions constrain the mossy fiber terminal-field distribution but, rather, suggest that the organization of the mossy fiber projections follows the compartmentation of the Purkinje cells.

Saliva protein binding to layers of oral streptococci in vitro and in vivo

This paper reports a system for measuring saliva protein binding to oral streptococci. Enamel chips with layers of Streptococcus gordonii Blackburn or Streptococcus oralis 10557 were incubated in vitro with whole saliva from eight persons. Blackburn bound significantly more amylase than 10557; no strain differences were seen for lysozyme or lactoferrin. There were significant correlations between saliva and bound amylase and lactoferrin. Blackburn and 10557 chips were then placed in ten subjects. Sites included the buccal left and right upper premolars and molars (UL, UR), labial upper central incisors (UC), and lingual lower central incisors (LL). That study was repeated three months later; chips with Streptococcus sanguis 13379 were also placed then. Blackburn bound significantly more amylase than the other strains. Blackburn and 10557 both bound the most amylase at UL and UR, and the least amylase at UC. However, strain 13379 bound less amylase at UL. That strain also bound significantly less sIgA at UL. All three strains bound the least sIgA at UC. Lysozyme and lactoferrin binding showed few differences among sites or strains. Bound protein concentrations were significantly correlated across sites and strains within subjects, but not correlated with whole saliva. Strain differences may reflect species differences in amylase binding, or differences in species-specific sIgA titers. Site differences may indicate local variation in protein availability. Differences between chip correlations with whole saliva in vitro and in vivo suggest that the salivary film may be modified as it flows over tooth surfaces.

The prediction of saliva swallowing frequency in humans from estimates of salivary flow rate and the volume of saliva swallowed

Saliva swallowing frequency is an important factor in models of oral clearance. It varies widely among individuals, and the basis for that variation has not been established. This study evaluated the use of unstimulated flow rate and the volume of saliva swallowed as predictors of swallowing frequency in 128 first-year dental students. A microphone was placed over the larynx, and swallowing activity was recorded for 30 min between 3-6:00 p.m. The average interval between swallows was determined, and individuals retained saliva in the mouth for a period equal to that time. Retained saliva was spat out, and volume was determined gravimetrically. Four replicate tubes were collected. Flow rate was determined as sample volume over average swallow time. A subset of 10 individuals was measured on two further occasions 2-3 months apart. An independent estimate of flow rate was taken on the second occasion. Repeat-measures analysis of variance and intraclass correlations were used to estimate the reproducibility of replicate volumes, and of measurements taken on different occasions. Associations between swallowing interval, saliva volume, and flow rate were evaluated by multiple regression. Replicate volumes were highly reproducible, as were measurements of volumes, swallow times, and flow rates on different occasions. Saliva volume and flow rate jointly accounted for 99% of variance in swallowing intervals. Swallowing intervals were shortest for individuals who combined high flow rates with small saliva volumes; current models suggest that their oral clearance might be most efficient. Swallowing intervals were longest for individuals with low flow rates and large volumes; their oral clearance might be the least efficient.

[Clinical application of immediate intraoperative expansion technique]

Since June 1992, 14 patients with skin or soft tissue defects from resection of scar or nevus were treated using the technique of immediate intraoperative expansion with good results. The operative procedure, indications and key points are discussed. We concluded that immediate intraoperative expansion may be accepted as a simple, safe and effective technique for the repair of the skin defects, which can be sutured directly under great tension.

[The role of platelet activating factor in mesenterioangial microcirculatory disturbance complicated with acute pancreatitis in rats]

To study shock in early acute pancreatitis (AP), we observed the change of mesenterio-angial microcirculation in the rat with AP induced by sodium taurocholate infused into the pancreatic duct. Meanwhile, the effect of platelet activating factor (PAF) receptor antagonist BN52021 upon the animal with AP was also investigated. 18 Sprague-Dawley rats were divided into three groups: pancreatitis group pan + BN52021 group and control group. pan + BN52021 group was injected BN52021 (10mg/kg) intravenously 5 minutes and 180 minutes after AP induction. The other groups were injected normal saline. We also studied the survival times of rats. The results showed slow mesenterio-angial small arteriolar and venular blood flow velocity and dilated meseaterio-angial small venular diameter during the early phase of AP. An protective effect of BN52021 on mesenterio-angial microcirculation injuries accompanied by AP was confirmed Animals treated with BN52021 survived 458.3 +/- 9.5 minutes whereas death occurred 243.3 +/- 2.3 minutes after AP induction in untreated rats (P < 0.01).

Synthesis and anti-cancer activity of 2-alkylaminomethyl-5-(E)-alkylidene cyclopentanone hydrochlorides

A series of 2-alkylaminomethyl-5-(E)-alkylidene cyclopentanone hydrochlorides (2), have been synthesized and evaluated as anti-cancer agents. These compounds were designed as masked alpha-methylenecyclopentanones, which appear in many cytotoxic or anti-cancer natural products. Most of the synthesized compounds were found to be active towards various human cancer cell lines and many showed significant subpanel selectivity. For compounds containing the same alkylidene moiety (from C3 to C9), the dimethylaminomethyl analogs were more active than structures possessing morpholino-, pyrrolidino-, or piperidino-methyl groups. Alteration of the alkylidene moiety had little effect on anti-cancer potency. The mass spectrum of a glutathione adduct of 2h indicated that the mechanism of action for these anti-cancer agents may be related to the attack at the aminomethyl carbon atom by biological nucleophilic thiols.

Topography of Purkinje cell compartments and mossy fiber terminal fields in lobules II and III of the rat cerebellar cortex: spinocerebellar and cuneocerebellar projections

The cerebellar cortex is histologically uniform by conventional staining techniques, but contains an elaborate topography. In particular, on the efferent side the cerebellar cortex can be subdivided into multiple parasagittal compartments based upon the selective expression by Purkinje cell subsets of various molecules, for example the polypeptide antigens zebrin I and II, and on the afferent side many mossy fibers terminate as parasagittal bands of terminals. The relationships between mossy fiber terminal fields and Purkinje cell compartments are important for a full understanding of cerebellar structure and function. In this study the locations of spino- and cuneocerebellar mossy fiber terminal fields in lobules II and III of the rat cerebellum are compared to the compartmentation of the Purkinje cells as revealed by using zebrin II immunocytochemistry. Wheat germ agglutinin-horseradish peroxidase was injected at three different levels in the spinal cord and in the external cuneate nucleus, and the terminal field distributions in lobules II and III of the cerebellar cortex were compared with the Purkinje cell compartmentation. In the anterior lobe, zebrin II immunocytochemistry reveals three prominent, narrow immunoreactive bands of Purkinje cells, P1+ at the midline and P2+ laterally at each side. These are separated and flanked by wide zebrin- compartments (P1- and P2-). There are also less strongly stained P3+ and P4+ bands more laterally. The spinocerebellar terminals in the granular layer are distributed as parasagittally oriented bands. Projections from the lumbar region of the spinal cord terminate in five bands, one at the midline (L1), a second with its medial border midway across P1- and its lateral border at the P2+/P2- interface (L2), and a third extending laterally from midway across P2-. The lateral edge of L3 may align with the P3+/P3- border. The terminal fields labeled by a tracer injection into the thoracic region give a very similar distribution (T1, T2 and T3). The only systematic difference is in T2, which statistical analysis suggests may be broader than L2. In contrast, anterograde tracer injections into the cervical region label synaptic glomeruli scattered throughout the lobule with much weaker or no evidence of banding. The terminal fields of the cuneocerebellar projection have a complementary distribution to those of thoracic and lumbar spinocerebellar terminals. There are two lateral bands, Cu2 and Cu3. Cu2 lies within the Purkinje cell P1-compartment, abutting L1/T1 medially and L2/T2 laterally. Cu3 lies between L2 and L3 within the P2- Purkinje cell compartment. The medial edge of Cu3 is tightly aligned with the P2+/P2- border.(ABSTRACT TRUNCATED AT 400 WORDS)

Sjögren's syndrome: cytokine and Epstein-Barr viral gene expression within the conjunctival epithelium

PURPOSE

In primary Sjögren's syndrome (SS), ocular surface changes within the conjunctival epithelium include lymphocytic infiltration, squamous cell metaplasia, and a reduction in goblet cell number. These changes may be the simple result of increased mechanical abrasion secondary to dryness. Alternatively, they may represent a local response to ocular and/or systemic inflammatory processes, perhaps in response to Epstein-Barr viral (EBV) infection, an agent recently implicated in the etiology of SS. To determine whether inflammatory processes or local infection by EBV contribute to the ocular surface pathology of SS, we examined the expression of inflammatory cell surface markers, cytokines, and EBV gene products within the ocular conjunctiva of patients with SS.

METHODS

Ocular conjunctival tissue was isolated from patients with primary SS and nondry eye control patients by impression cytology or direct biopsy. These specimens were examined by immunofluorescence microscopy and reverse-transcriptase polymerase chain reaction (RT-PCR) for the expression of various markers.

RESULTS

The authors found the frequency of expression of HLA-DR (P < 0.0001), ICAM-1 (P < 0.035), and IL-6 (P < 0.0001) to be significantly elevated in patients with primary SS versus nondry eye control patients. The IL-2 receptor and cytokines IL-1 beta and IL-8 were each found to be expressed with relatively high frequency in both patient populations, whereas mRNAs encoding cytokines IL-2, IFN-gamma, GM-CSF, and TGF-beta were not reproducibly detectable in either population. Messenger RNA encoding a marker for passive-latent EBV infection (EBNA-1) was detected with high frequency in both SS and normal populations. The EBV IL-10 analog BCRF-1 was expressed with low frequency in the SS population; however, these levels were not significantly different from the control population. The expression of two other markers of EBV infection, latent membrane protein (LMP, a lytic and latent marker), and BZLF-1 (putative latent-lytic switch gene) was undetectable in either study population.

CONCLUSION

Based on the increased expression of the cell surface molecules HLA-DR and ICAM-1, and the inflammatory cytokine IL-6, the authors propose that local inflammatory processes contribute to the ocular surface changes and ocular surface dryness associated with primary SS.

[Free medial leg flap with fasciocutaneous branch of tibial nutrient artery]

According to the results of anatomical study in 20 fresh cadaver legs and transparent specimens of 10 medial leg flaps, it is found that the tibial nutrient artery arises from the posterior tibial artery and runs obliquely downwards close to the surface of the popliteal muscle, and at the level of 61.62 +/- 15 mm below the tibial tuberosity it sends out the fasciocutaneous branch, which becomes one of the main nutritional vessels of the medial area of the leg. Vascularized transplantation of the medial leg free flap which is supplied by the fasciocutaneous branch of the above named artery has been undertaken with satisfactory results clinically.

Dissemination and replication of MCMV after supraciliary inoculation in immunosuppressed BALB/c mice

PURPOSE

To study replication and dissemination of murine cytomegalovirus (MCMV) in immunosuppressed (IS) and non-IS BALB/c mice after ocular inoculation via the supraciliary route.

METHODS

BALB/c mice were immunosuppressed by injections of methylprednisolone, and MCMV was injected via the supraciliary route. Ocular and nonocular tissues from both IS and non-IS mice were studied by plaque assay of tissue homogenates. The frequency of virus-positive leukocytes was determined by PCR.

RESULTS

In the inoculated eye, virus replication was significantly higher in both the anterior segment and the posterior segment of IS mice. Virus spread to extraocular sites in both IS and non-IS mice; however, significantly higher titers of virus were recovered from the salivary glands and lungs of IS mice than from non-IS mice, and clearance of virus from these sites was delayed in IS mice. Virus spread from the injected eye via leukocytes, and PCR amplification revealed that the frequency of virus-infected leukocytes was approximately 200-fold higher in IS mice.

CONCLUSIONS

The results of these studies suggest that immunosuppression significantly enhances virus replication in the inoculated eye, salivary glands, and lungs, leads to a higher frequency of virus-positive leukocytes, and delays clearance of virus from ocular and nonocular tissues. These results also suggest that retinitis in the injected eye of IS mice correlates with significantly higher titers of virus in the posterior segment.

Nicotine's opioid and anti-opioid interactions: proposed role in smoking behavior

Nicotine produced antinociception in mice which was antagonized noncompetitively by naloxone. In addition, at significantly lower doses, nicotine noncompetitively antagonized morphine-induced antinociception. A speculative suggestion regarding the opiatergic and anti-opiatergic actions of nicotine is that it significantly promotes and maintains smoking behavior.

Structural and molecular compartmentation in the cerebellum

Most descriptions treat the cerebellum as a uniform structure, and the possibility of important regional heterogeneities in either chemistry or physiology is rarely considered. However, it is now clear that such an assumption is inappropriate. Instead, there is substantial evidence that the cerebellum is composed of hundreds of distinct modules, each with a precise pattern of inputs and outputs, and expressing a range of molecular signatures. By screening a monoclonal antibody library against cerebellar polypeptides we have identified antigens--zebrins--that reveal some of the cerebellum's covert heterogeneity. This article reviews some of these findings, relates them to the patterns of afferent connectivity, and considers some possible mechanisms through which the modular organization may arise.

Partial elimination of Epstein-Barr virus plasmids from Burkitt's lymphoma cells by transfecting the BZLF1 gene

Epstein-Barr virus (EBV) nonproducer Raji cells stably maintain approximately 45 copies of the EBV genome per cell, depending on the presence of the EBV-determined nuclear antigen 1 (EBNA-1) protein. We found that transfection of the EBV BZLF1 gene causes the disappearance of EBNA proteins on Western blots (immunoblots). On the basis of these results, we attempted to eliminate EBV plasmids in Raji cells by transfecting a BZLF1 plasmid. Among 33 clones that were cotransfected with a BZLF1 plasmid and a hygromycin B resistance plasmid and selected resistant for hygromycin B, 24 clones had decreased numbers of EBV plasmids, as revealed by the decrease in the intensity of the EBV band on Southern blots compared with that of nontransfected Raji cells.

Erythrocyte vesiculation in paroxysmal nocturnal hemoglobinuria

Red blood cells from patients with paroxysmal nocturnal hemoglobinuria (PNH) were found to be liable to vesiculate, as demonstrated by both DMPC liposome- and CaCl2-induced vesiculation and measured in terms of acetylcholinesterase activity and 3H-inositol radioactivity in the supernatant. Membrane proteins released from the cells during vesiculation included several constituents with molecular weights identical to those of some complement regulating factors (e.g. DAF) which play an essential role in complement-mediated hemolysis. Red blood cells from both normal and PNH patients showed decreased deformability after vesiculation. Liability to vesiculate and the consequential loss of certain essential membrane proteins and decreased deformability might be a factor contributing to the mechanism of hemolysis in PNH.

[Assay of moniliformin content in household grains from families in patients with Keshan disease]

Ion-pairing extraction and high-performance liquid chromatography (HPLC) were employed for assaying moniliformin (a fungal toxin) content in the corn (Shaanxi) and rice (Yunnan) samples collected from families suffering from Ke-shan disease. The highest contents were found to be 264 micrograms/kg (corn) and 252 micrograms/kg (rice), while a rice sample from Beijing market showed none. The identity of moniliformin was confirmed by 2D-UV detection and co-HPLC with a synthetic toxin sample. These results strongly support the view that moniliformin is a pathogenic factor of Ke-shan disease.

Regulatory control of the terminal complement proteins at the surface of human endothelial cells: neutralization of a C5b-9 inhibitor by antibody to CD59

Functionally inhibitory antibody to the plasma membrane complement inhibitor CD59 has been used to investigate control of the terminal complement proteins at the endothelial cell surface. Antibodies against purified human erythrocyte CD59 (polyclonal anti-CD59 and monoclonal antibodies [MoAbs] 1F1 and 1F5) were found to bind specifically to monolayers of cultured human umbilical vein endothelial cells, and by Western blotting to recognize an 18- to 21-Kd endothelial protein. When bound to the endothelial monolayer, anti-CD59 (immunoglobulin G or Fab fragment) potentiated membrane pore formation induced upon C9 binding to C5b-8, and augmented the C5b-9-induced cellular responses, including stimulated secretion of von Willebrand factor and expression of catalytic surface for the prothrombinase enzyme complex. Although potentiating endothelial responses to the terminal complement proteins, anti-CD59 had no effect on the response of these cells to stimulation by histamine. Taken together, these data suggest that human endothelial cells express the CD59 cell surface inhibitor of the terminal complement proteins, which serves to protect these cells from pore-forming and cell-stimulatory effects of the C5b-9 complex. These data also suggest that the inactivation or deletion of this cell surface regulatory molecule would increase the likelihood for procoagulant changes in endothelium exposed to complement activation in plasma.