Survival prolongation in HIV-associated progressive multifocal leukoencephalopathy treated with alpha-interferon: an observational study

A retrospective chart review was conducted to determine the effect of alpha-Interferon (alpha-IFN) on disease progression, symptom palliation, and survival in HIV-associated Progressive Multifocal Leukoencephalopathy (PML).

METHODS

Subjects were HIV seropositive patients diagnosed with PML at the Johns Hopkins Hospital between 1985 and July of 1986. Diagnostic criteria for PML included both clinical symptomatology and histologic or radiographic confirmation. All patients with concomitant CNS infections were excluded. Patients receiving a minimum treatment of 3 weeks of 3 million units of alpha-IFN daily were compared to untreated historical controls. From 104 PML cases reviewed, 77 met the defined criteria for PML. Twenty-one patients had received open-label alpha-IFN treatment in a non-randomized manner for at least 3 weeks, and 32 met criteria for inclusion in the untreated group as historical controls. Deceased treated patients were comparable to deceased untreated patients with respect to age, gender, race, HIV risk factors, AIDS-defining illnesses, and CD4+ counts. CD4+ counts and use of anti-retroviral medications within 6 months of PML onset were higher among those who were living at the time of the study.

RESULTS

Among deceased patients, median survival of treated patients was 127.5 days longer than that of untreated patients (Chi-square=4.21, P=0.04). When living and deceased treated patients were combined, the median survival was 325 days (range 35 - 1634) versus 121 days (range 46 - 176) in untreated patients (Chi-square=13.47, P < 0.001). When survival times in untreated patients were left-censored to account for possible survivorship bias in treated patients, survival in treated patients remained significantly prolonged (325 days versus 175.5 days, Chi-square=4.65, P=0.03). In addition, use of alpha-IFN was associated with a significant delay in the onset of memory loss (Chi-square=8.59, P < 0.01). Seven alpha-IFN treated patients showed sustained remissions of several months to over a year, with documented improvements in mental status, aphasia, dysarthria, dysphagia, paresis, and dyscoordination. Moreover, four IFN-treated patients had evidence of MRI lesion regression, although this was not always correlated with clinical remission. Four of 32 untreated patients also reported transient symptomatic improvements.

CONCLUSION

This open-label study suggests that alpha-IFN may delay progression, palliate symptoms, and significantly prolong survival in HIV-associated PML, and we therefore suggest that a controlled clinical trial is warranted.

Effects of d-amphetamine on the frequency of the spontaneous contraction of the portal vein in rat

1. Effects of d-amphetamine on the frequency of spontaneous contraction of the longitudinal muscle of the portal vein were studied in Wistar rats. Its effects on the circular muscles of the pulmonary artery and stomach also were tested. 2. d-Amphetamine increased the frequency of the spontaneous contraction of the portal vein. The ratio of the frequency of the spontaneous contraction of the portal vein before and after d-amphetamine treatment also was increased. The effect was not affected in the presence of prazocin, (+)-lysergic acid diethylamide, atropine and haloperidol. These results that the d-amphetamine-elicited response was not due mainly to the activation of adrenergic, serotoninergic (5-HT), cholinergic or dopaminergic receptors. 3. Increasing extracellular calcium or sodium ion concentrations decreased the frequency of the spontaneous contraction of the portal vein. However, the ratios of the frequency of the spontaneous contraction of the rat portal vein before and after d-amphetamine treatment in media containing different extracellular calcium or sodium concentrations were not significantly altered. Tetrodotoxin did not alter the effect of d-amphetamine on the frequency of spontaneous contractions. It appeared that calcium and sodium ions may not take part in the effects of d-amphetamine on the frequency of the portal vein. 4. An increase in extracellular potassium ion concentrations increased the frequency of the spontaneous contractions of the portal vein. In addition, the ratios of the frequency of the spontaneous contractions of the rat portal vein before and after d-amphetamine treatment in media containing different extracellular potassium ion concentrations were significantly altered. Tetraethylammonium chloride (TEA) and 4-aminopyridine (4-AP) increased the spontaneous contractions of the portal vein. However, TEA and 4-AP did not increase the d-amphetamine-elicited increasing effect on the frequency of spontaneous muscle contractions. 5. Levochromakalim, a potassium channel opener, decreased the frequency of the spontaneous contractions of the portal vein. Levochromakalim also decreased the effect of d-amphetamine on the frequency of spontaneous contractions of the muscle. It appeared that potassium ion may be associated with the effects of d-amphetamine on the activity of the portal vein. 6. d-Amphetamine potentiated, whereas prazosin decreased, the noradrenaline-elicited contracture of the rat pulmonary artery in a dose-dependent manner. 7. d-Amphetamine elicited contracture of the circular muscle of rat stomach, whereas it did not alter the frequency of the spontaneous contraction of the muscle. 8. Both 5-HT and d-amphetamine elicited the contracture of the circular muscle of rat stomach. Ketanserin decreased the 5-HT-elicited response, whereas it did not alter the d-amphetamine-elicited response in the muscle. d-Amphetamine did not alter the frequency of the spontaneous contraction of the stomach. 9. It is concluded that d-amphetamine has different effects on the frequency of spontaneous smooth muscle contractions. It increased the frequency in the portal vein, but it did not alter the frequency in stomach circular muscle.

A pentacosapeptide (CKS-25) homologous to retroviral envelope proteins possesses a transforming growth factor-beta activity

CKS-17, a synthetic heptadecapeptide homologous to a conserved domain in retroviral envelope protein p15E, mimics the immunosuppressive properties of p15E in vitro and in vivo, but the mechanisms are not understood. Here we report that a synthetic pentacosapeptide designated CKS-25, a longer version of CKS-17 that contains a functional transforming growth factor-beta3 (TGF-beta3) active-site motif (RXXD), inhibits 125I-labeled TGF-beta1 (125I-TGF-beta1) binding to cell-surface TGF-beta receptors in cultured epithelial cells. Multiple conjugation of CKS-25 to bovine serum albumin and carbonic anhydrase enhances the 125I-TGF-beta1 binding inhibitory activity and confers a partial TGF-beta agonist activity (growth inhibition but not transcriptional activation). Since TGF-beta is a potent immunosuppressive factor, these results suggest that the immunosuppressive properties of CKS-17-bovine serum albumin conjugate and p15E are mediated at least in part by their TGF-beta agonist activities.

Trilinolein inhibits the adhesion of neutrophils to endothelial cells

1. Trilinolein is a triacylglycerol with linoleic acid as the only type of fatty acid in all three esterified positions of glycerol. It was recently reported to have a myocardial protective effect in coronary ligated rats. We now study its effect on the adhesion of human neutrophils to cultured bovine endothelial cells. 2. Pretreatment of an endothelial monolayer with trilinolein at concentrations ranging from 10(-10) to 10(-6) mol/L significantly inhibited neutrophil adhesion to endothelial cells. Trilinolein was less potent than sodium nitroprusside in inhibiting neutrophil adhesion. 3. The inhibitory effect of trilinolein was antagonized by methylene blue and N(G)-nitro-L-arginine methyl ester. The inhibitory effect of trilinolein was not mediated through linoleic acid because linoleic acid did not inhibit neutrophil adhesion. 4. Pretreatment of neutrophils with trilinolein did not reduce neutrophil adhesion. However, in neutrophils activated with N-formyl-methionyl-leucyl-phenylalanine, trilinolein inhibited the neutrophil adhesion to endothelial cells. 5. We conclude that trilinolein inhibits neutrophil adhesion to the endothelial monolayer by stimulating the nitric oxide and cyclic GMP pathways in endothelial cells. It may also inhibit neutrophil adhesion by scavenging free radicals. The inhibitory effect of trilinolein on neutrophil adhesion may play a role in its myocardial protective activity.

The accuracy of medical records and police reports in determining motor vehicle crash characteristics

OBJECTIVE

To determine the accuracy of police, emergency department, and ambulance records in describing motor vehicle crash (MVC) characteristics when compared with a crash investigation report (CIR).

METHODS

This study was a retrospective record review. Sixty-three motor vehicle crash (MVC) patients transported to a university hospital emergency department via ambulance and also reported in a crash investigation record (CIR) during the period January 1993 to December 1995 comprised the study population. The crash characteristics analyzed were occupant position (OP), restraint use (RU), air bag deployment (AD), type of impact (TI), ejection (EJ), and external cause-of-injury code (EC). The accuracies of the police report (PR), the emergency department record (EDR), and the ambulance report (AR) for each patient were compared with the CIR by computing percent agreement, with 95% confidence intervals (95% CIs) for each variable and for each data source.

RESULTS

Overall average agreement was 92.9% for PR, 89.7% for EDR, and 80.7% for AR. The overall average agreement for each variable was 98.9% for EJ, 92.1% for AD, 91.5% for OP, 90.5% for EC, 77.2% for RU, and 76.2% for TI. For all but one variable (RU), 95% CIs overlapped between data sources.

CONCLUSIONS

The accuracy of data sources used to determine crash characteristics varies. Using a CIR as the standard, the PR was the most accurate. Inaccuracies occurred most frequently for RU and TI. Researchers and clinicians need to be aware of these inaccuracies.

Laryngeal candidiasis in children

Candidiasis of the larynx is rare and often related to immunocompromised hosts. We here report a case of laryngeal candidiasis in an immunocompetent infant. The diagnosis was obtained by direct fibre-optic laryngoscopy with specimens submitted for culture. He received anti-fungal medication and was quite well at 1-year follow up. The pertinent literature is also reviewed.

Suramin enters and accumulates in low pH intracellular compartments of v-sis-transformed NIH 3T3 cells

Using acridine orange as a reporter compound, we demonstrate that suramin enters and accumulates in low pH intracellular compartments (endosomes, lysosomes, and trans-Golgi complex) of normal and v-sis-transformed NIH 3T3 cells. The concentration of suramin in these acidic compartments is estimated to be > 150 microM, higher than the concentration known to completely inhibit interaction of the platelet-derived growth factor (PDGF) receptor and v-sis gene product. These results support the hypothesis that suramin reverses the transformed phenotype of v-sis-transformed cells by entering the cell via endocytosis and blocking interaction of the v-sis gene product and PDGF receptor in intracellular organelles.

Transforming growth factor beta peptide antagonists and their conversion to partial agonists

Transforming growth factor beta (TGF-beta) has been implicated in the pathogenesis of various human diseases. Synthetic TGF-beta antagonists therefore could have therapeutic utility. Here we show the development of such compounds. Three synthetic pentacosapeptides designated beta125-(41-65), beta225-(41-65), and beta325-(41-65), whose amino acid sequences correspond to the 41st to 65th amino acid residues of TGF-beta1, TGF-beta2, and TGF-beta3, respectively, inhibit the binding of 125I-labeled TGF-beta isoforms to TGF-beta receptors in mink lung epithelial cells with IC50 of approximately 0.06-2 microM. beta125-(41-65) blocks TGF-beta1-induced growth inhibition and TGF-beta1-induced plasminogen activator inhibitor-1 expression in these cells. The variants designated beta125-(41-65)W52A/D55A and beta325-(41-65)R52A/D55A, in which both Trp52/Arg52 and Asp55 are replaced by alanine residues, do not have TGF-beta antagonist activity. Multiple conjugation of beta125-(41-65) to carrier proteins enhances its antagonist activity but also confers partial agonist activity as measured by DNA synthesis inhibition. These results suggest that the (W/R)XXD motif is important for the activities of these TGF-beta peptide antagonists and that this motif may be the active site sequence of TGF-beta.

Effects of 3,3-dipyridylmethyl-1-phenyl-2-indolinone on gamma-aminobutyric acid elicited chloride current of snail central neuron

The effects of (1) gamma-aminobutyric acid (GABA) on the excitable membrane and (2) DPMPI (3,3-dipyridylmethyl-1-phenyl-2-indolinone) on the microperfused GABA elicited currents were investigated on central LP5 neuron of giant African snail, Achatina fulica Ferussac, with conventional voltage-clamp technique. GABA elicited an inward current of LP5 neuron by a concentration and voltage dependent manner. Muscimol, GABAA receptor agonist, did, while baclofen, GABAB receptor agonist, did not, elicit the membrane current on the neuron. The GABA elicited currents in LP5 neuron were blocked by picrotoxin, a GABAA receptor ion channel complex antagonist while the currents were not blocked by phaclofen, a GABAB receptor antagonist. The results suggested that the GABA elicited current in LP5 neuron was mainly due to activation of GABAA receptor. DPMPI increased the frequency of the spontaneously generated action potential of the neuron. In the voltage clamped neuron, DPMPI decreased the GABA elicited responses by a concentration dependent manner. DPMPI altered neither the reversal potential of GABA elicited current, nor the membrane resistance of the excitable membrane of central LP5 neuron. The results concluded that DPMPI altered the GABAA activated receptor ionic channel complex of the LP5 neuron.

The type V transforming growth factor beta receptor is the putative insulin-like growth factor-binding protein 3 receptor

Insulin-like growth factor-binding protein 3 (IGFBP-3) has been shown to inhibit cell growth by IGF-dependent and -independent mechanisms. The putative cell-surface IGFBP-3 receptor that mediates the IGF-independent growth inhibition has not been identified. Here we show that recombinant human IGFBP-3 inhibits 125I-transforming growth factor (TGF)-beta1 binding to the type V TGF-beta receptor (Mr 400,000) in mink lung epithelial cells. We also demonstrate that the approximately 400-kDa 125I-IGFBP-3 affinity-labeled putative IGFBP-3 receptor is immunoprecipitated by specific antiserum to the type V TGF-beta receptor. The 125I-IGFBP-3 affinity labeling of the putative receptor and IGFBP-3-induced growth inhibition as measured by DNA synthesis in these cells is blocked by a TGF-beta1 peptide antagonist. The 125I-IGFBP-3 affinity-labeled putative receptor can only be detected in cells expressing the type V TGF-beta receptor, but not in cells lacking the type V TGF-beta receptor. These results indicate that the type V TGF-beta receptor is the putative IGFBP-3 receptor and that IGFBP-3 is a functional ligand for the type V TGF-beta receptor.

Function of the type V transforming growth factor beta receptor in transforming growth factor beta-induced growth inhibition of mink lung epithelial cells

The type V transforming growth factor beta (TGF-beta) is a 400-kDa nonproteoglycan membrane protein that co-expresses with the type I, type II, and type III TGF-beta receptors in most cell types. The type V TGF-beta receptor exhibits a Ser/Thr-specific protein kinase activity with distinct substrate specificity (Liu, Q., Huang, S. S., and Huang, J. (1994) J. Biol. Chem. 269, 9221-9226). In mink lung epithelial cells, the type V TGF-beta receptor was found to form heterocomplexes with the type I TGF-beta receptor by immunoprecipitation with antiserum to the type V TGF-beta receptor after 125I-TGF-beta affinity labeling or Trans35S-label metabolic labeling of the cells. The kinase activity of the type V TGF-beta receptor was stimulated after treatment of mink lung epithelial cells with TGF-beta. TGF-beta stimulation resulted in the growth inhibition of wild-type mink lung epithelial cells and to a lesser extent of the type I and type II TGF-beta receptor-defective mutants, although higher concentrations of TGF-beta were required for the growth inhibition of these mutants. TGF-beta was unable to induce growth inhibition in human colorectal carcinoma cells lacking the type V TGF-beta receptor but expressing the type I and type II TGF-beta receptors. These results suggest that the type V TGF-beta receptor can mediate the TGF-beta-induced growth inhibitory response in the absence of the type I or type II TGF-beta receptor. These results also support the hypothesis that loss of the type V TGF-beta receptor may contribute to the malignancy of certain carcinoma cells.

Myocardial protective effect of honokiol: an active component in Magnolia officinalis

Honokiol is an active component of Magnolia officinalis. It was reported to be 1000 times more potent than alpha-tocopherol in inhibiting lipid peroxidation in rat heart mitochondria. In this study, we investigated the in vivo antiarrhythmic and antiischemic effects of honokiol in coronary ligated rats. Male Sprague-Dawley rats were anesthetized with urethane. Honokiol, at dosages of 10(-7) g/kg, 10(-8) g/kg, and 10(-9) g/kg, was administered intravenously 15 min before ligation of the coronary artery. Incidence and duration of ventricular tachycardia and ventricular fibrillation during 30 min coronary ligation were significantly reduced by 10(-7) g/kg honokiol. Ventricular arrhythmia during 10 min reperfusion after the relief of coronary ligation was also reduced. In rats subjected to 4 hours coronary ligation, 10(-7) g/kg, 10(-8) g/kg, and 10(-9) g/kg honokiol significantly reduced the infarct zone. We concluded that honokiol may protect the myocardium against ischemic injury and suppress ventricular arrhythmia during ischemia and reperfusion.

[Cholecystokinin-octapeptide (CCK-8) reverses experimental endotoxin shock]

The effects of CCK-8 on the mean arterial pressure (MAP), blood components and path-morphological changes during endotoxin shock (endotoxin, 8 mg/kg b.w.iv.) in rats, as well as on the 24 h mortality rate (MR) of the lead-sensitized rats in endotoxin shock (endotoxin 1 microgram/100 g b.w.iv.) were observed. The results showed that injection of CCK in ES rats led to an increase in MAP, and a reduction of hematocrit and platelet as well as white cell count; the mortality rate decreased and the lesion in main organs lessened. It is suggested that release of endogenous CCK has important protective action during endotoxin shock.

Magnolol reduces infarct size and suppresses ventricular arrhythmia in rats subjected to coronary ligation

1. Magnolol is an active component of Magnolia officinalis. It is 1000-times more potent than alpha-tocopherol in inhibiting lipid peroxidation in rat heart mitochondria. In the present study, the in vivo antiarrhythmic and anti-ischaemic effects of magnolol in coronary ligated rats were investigated. 2. Male Sprague-Dawley rats were anaesthetized with urethane. Magnolol, at dosages of 10(-7), 10(-8) and 10(-9) g/kg, was administered intravenously 15 min before ligation of the coronary artery. 3. The incidence and duration of ventricular tachycardia and ventricular fibrillation during 30 min coronary ligation were significantly reduced by magnolol. Ventricular arrhythmias during 10 min reperfusion after the relief of coronary ligation were also reduced. 4. In rats subjected to 4 h coronary ligation, 10(-7) and 10(-8) g/kg magnolol significantly reduced infarct size. 5. We conclude that magnolol may protect the myocardium against ischaemic injury and suppress ventricular arrhythmia during ischaemia and reperfusion.

Characterization of retinal vascular abnormalities in lean and obese spontaneously hypertensive rats

1. The obese SHR (Koletsky rat; SHR-k) is a unique animal model for the study of microvascular changes associated with genetic obesity, spontaneous hypertension, endogenous hyperlipidaemia, and hyperinsulinaemic, non-insulin dependent diabetes mellitus (Type II). 2. Lean and obese SHR-k exhibit retinal vascular changes which have not been previously characterized and are more severe than previously described in other animal models of experimental hypertension or non-insulin dependent diabetes. 3. Progressive retinal capillary dropout, capillary cell changes, vascular tortuosity and dilatation are severe. Vessels form elevated varicose vascular tortuosities which leak fluorescein dye and which are more frequent in the obese SHR-k. This study suggests that lean and obese SHR may be unique models for the study of multivariate factors in the pathogenesis of ischaemic neovascular proliferation.

Effect of yogurt on symptoms and kinetics of hydrogen production in lactose-malabsorbing children

Lactase-deficient adults demonstrate improved lactose absorption and fewer symptoms when consuming yogurt than when consuming milk containing equivalent amounts of lactose. To examine this effect and its mechanisms in children, we compared symptoms and hydrogen production as an index of lactose malabsorption after typical servings of milk, pasteurized yogurt, and yogurt containing active live culture in 14 lactose-malabsorbing children (mean age 9.5 y). Symptoms and interval breath-hydrogen concentrations were recorded for 8 h after ingestion of 12 g lactose served as milk and yogurts. Lactose-malabsorbing children experienced significantly fewer symptoms after consuming yogurt containing active cultures than after consuming milk (P < 0.005). Pasteurized yogurt showed an intermediate effect. Lactose from yogurt was not better absorbed than was lactose from milk, as indicated by similar areas under the hydrogen curve; however, yogurt was associated with a delayed time to rise and lower rate of rise of the hydrogen curve. The rate of hydrogen rise correlated with the degree of symptoms. In children, mechanisms other than enhanced lactose absorption from yogurt may lead to changes in the kinetics of hydrogen production, which in turn are associated with improved tolerance.

Processing of prothyrotropin-releasing hormone (Pro-TRH) by bovine intermediate lobe secretory vesicle membrane PC1 and PC2 enzymes

TRH is synthesized from a larger 26-kilodalton (kDa) prohormone (pro-TRH). Rat pro-TRH contains five copies of the TRH progenitor sequence (Gln-His-Pro-Gly) and seven other cryptic peptides. Each of the five TRH progenitor sequences is flanked by pairs of basic amino acids. We used a bovine intermediate lobe secretory vesicle membrane preparation, which contains the prohormone convertases (PCs) PC1 and PC2, to study the in vitro processing of pro-TRH. Pro-TRH was radiolabeled using [3H]Leu in AtT20 cells transfected with prepro-TRH complementary DNA, and the labeled 26-kDa pro-TRH was isolated from the cell extract by preparative sodium dodecyl sulfate-gel electrophoresis. Incubation of [3H]pro-TRH with the intermediate lobe secretory vesicle membrane preparation was followed by immunoprecipitation with antibodies specific for various regions of the pro-TRH sequence, and the immunoprecipitates were analyzed by sodium dodecyl sulfate-gel electrophoresis. Immunoprecipitation of the reaction mixture with anti-pCC10 antibody (an antibody that recognizes the intact precursor and amino-terminal intermediate products of processing) showed a time-dependent appearance of a 15-kDa and a 6-kDa peptide and, at times, a 3.8-kDa peptide with diminution of the 26-kDa substrate. Immunoprecipitation of the incubate with the C-terminal-directed antibody, pYE17 (an antibody that recognizes the intact precursor and C-terminal intermediate products of processing), showed the generation of 16.5-, 10-, and 5.4-kDa products in a time-dependent manner, with disappearance of the substrate. Western blot analysis demonstrated that the secretory vesicle membrane preparation contains PC1 and PC2. Immunodepletion studies with antiserum specific for PC1 or PC2 demonstrated that PC1 and PC2 can process pro-TRH to these intermediate products. An initial site of cleavage appeared to be either at the 152-153 or the 158-159 pair of basic residues to yield a 15-kDa N-terminal fragment that was then processed to the 6-kDa [TRH-(25-74)] and 3.8-kDa [TRH-(83-112)] forms. The 10-kDa C-terminal peptide generated by this cleavage was then processed to a 5.4-kDa peptide [TRH-(208-255)]. Alternatively, an initial cleavage at the 107-108 or the 112-113 bonds was also observed, yielding a 16.5-kDa C-terminal product that was further processed to the 5.4-kDa peptide. The pH profile for the appearance of both C- and N-terminal products showed a bimodal distribution, with optima at both 5.5 and 7.5. The cleavage of pro-TRH was enhanced by Ca2+ and partially inhibited by Zn2+.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of anthraquinone derivatives on lipid peroxidation in rat heart mitochondria: structure-activity relationship

Lipid peroxidation was induced in rat heart mitochondria with FeSO4 and the inhibitory effects of various anthraquinone derivatives were compared. Oxygen consumption and malondialdehyde formation were used to quantitate the amount of lipid peroxidation. Emodin [2], alizarin [13], and alizarin complexone [14] significantly inhibited lipid peroxidation; their potency as inhibitors of lipid peroxidation was higher than that of alpha-tocopherol. Structure-activity analysis showed that two hydroxyl groups arranged in either the ortho- or meta-position in the C ring of the anthraquinone nucleus are required for such derivatives to inhibit lipid peroxidation. The diphenyl-p-picrylhydrazyl test showed that alizarin [13] and alizarin complexone [14] are free-radical scavengers while emodin [2] is not. The mechanism for emodin [2] to inhibit lipid peroxidation is most likely due to inhibition on the propagation of lipid peroxyl radicals in the mitochondrial membrane.

Inhibition of alpha-fetoprotein production in a hepatoma cell line by antisense oligonucleotide analogues

alpha-Fetoprotein (AFP) is a fetal protein which is absent in adult serum. However, the AFP gene is expressed in some neoplastic cells. According to the literature, AFP may play a role in accelerating the growth of cancer cells. In this report, 15 meric antisense oligonucleotide analogues (phosphorothioates and methylphosphonates) and their chimeric forms, which were complementary to different regions of AFP mRNA, were synthesized, and their physical characteristics such as stability, melting temperature, and toxicity were compared. They were examined as to their inhibitor effects on the translation of AFP mRNA in a AFP-producing hepatoma cell line, HuH-7. We found that chimeric oligomers with methylphosphonate or phosphorothioate linkages at both the 5' and 3' ends were more effective than prototypic oligomers. Inhibition of 72% was achieved with a chimeric oligomer against the translational initiation region, at a concentration of 25 microM. No suppressive effect of the oligomers was observed on cell viability or albumin production, indicating the specificity of the inhibition.

The inhibitory effect of tannins on lipid peroxidation of rat heart mitochondria

We induced lipid peroxidation in rat heart mitochondria with ferrous sulphate (FeSO4) and compared the inhibitory effect of various tannins on the peroxidation. Oxygen consumption and malondialdehyde (MDA) formation were used to quantitate the amount of lipid peroxidation, and the free radical scavenger activity of tannins was measured with a diphenyl-p-picryl hydrazyl (DPPH) method. Of 25 tannins and related compounds tested, catechin benzylthioether and procyanidin B-2 benzylthioether were the most potent in inhibiting lipid peroxidation, with inhibitory effects stronger than that of trolox, a water soluble analogue of vitamin E. The concentrations (IC50) required for catechin benzylthioether and procyanidin B-2 benzylthioether to inhibit oxygen consumption to 50% of control values were 0.85 and 2.0 microM, respectively, while their IC50 values from the inhibition of MDA formation were 0.9 and 1.70 microM, respectively. The IC50 values for catechin, and procyanidin B-2 to inhibit oxygen consumption were 34.0 and 11.0 microM. Both compounds were less potent than their benzylthioether derivatives. However, the ability of catechin and procyanidin B-2 to scavenge DPPH were similar to that of their benzylthioether derivatives. We conclude that conjugation with a benzylthioether group enhances the inhibitor effect of tannins on lipid peroxidation, and that the mechanism is not an increase in its scavenger activity.

Identification, purification, and characterization of cell-surface retention sequence-binding proteins from human SK-Hep cells and bovine liver plasma membranes

Cell-surface retention is a newly identified mechanism associated with the secretion of certain polypeptide growth factors and cytokines. This novel form of secretion appears to be mediated by cell-surface retention sequences (CRS) in the polypeptide molecules. To test the hypothesis that high-affinity CRS-binding proteins (CRS-BPs) are responsible for the cell-surface retention, we identified and characterized the high-affinity binding sites on various cell types for 125I-labeled CRS peptide (sis) and CRS peptide (VEGF), each of which contained the putative CRS motifs of platelet-derived growth factor B (c-sis) and vascular endothelial cell growth factor, respectively. Scatchard plot analysis revealed a single class of high-affinity binding sites with Kd = 0.5-0.7 nM and approximately 22,000-55,000 sites/cell. High-affinity binding activity could be demonstrated between pH 4.5 and 8.0, but was much greater below 6.0 (maximum pH 5.0-5.5). The ligand binding activity was inhibited by heparin, polylysine, and protamine, but not by cytochrome c. CRS-BPs responsible for the high-affinity binding were identified as 60-72-kDa proteins by ligand affinity labeling. CRS-BPs were purified from human SK-Hep cells and bovine liver plasma membranes by Triton X-100 extraction followed by affinity column chromatography on wheat germ lectin-Sepharose 4B and CRS peptide (sis)-Affi-Gel 10. Purified CRS-BPs exhibited ligand binding properties (pH profile and inhibitor sensitivity) similar to those of the high-affinity binding sites for CRS peptides on cultured cells. The major CRS-BPs (p60, p66, and p72) purified from bovine liver plasma membranes were found to have identical N-terminal amino acid sequence and were assumed to represent different forms of the same gene product, which we have designated CRS-BP1.

Kinase activity of the type V transforming growth factor beta receptor

The type V TGF-beta receptor purified from bovine liver plasma membranes catalyzed the phosphorylation of casein using [gamma-32P]ATP as co-substrate (Km,app approximately 10 microM). TGF-beta stimulated the casein phosphorylation by the type V receptor with a half-optimal concentration of approximately 0.3 nM. Both TGF-beta-stimulated and -unstimulated phosphorylations occurred at serine residues. Amino acid sequences of 32P-labeled peptides from reverse phase HPLC of the tryptic digests of casein 32P-phosphorylated by the type V receptor were analyzed by automated Edman degradation. Alignment of phosphorylation site amino acid sequences of the 32P-labeled peptides revealed a recognition motif (S-X-E/S(P)) for the kinase activity of the type V receptor. The type V receptor catalyzed the phosphorylation of an octadecapeptide designated peptide SESTE (SKDIGS*ESITEDQAMEDKK) (the asterisk indicates the phosphorylated residue) containing the major phosphorylation site sequence of casein. The Km,app and Vmax for peptide SESTE were determined to be 0.3 microM and 2.2 nmol of 32P incorporation/min/mg of enzyme, respectively. The phosphorylation of peptide SESTE by the type V receptor was stimulated by TGF-beta or polylysine but inhibited by heparin. Like intact casein, peptide SESTE was phosphorylated at 2 close serine residues (-S*-E-S*-T-E-) by the type V receptor. The type V receptor also phosphorylated a variant of peptide SESTE, peptide AESTE (SKDIGAES*TEDQAMEDKK). However, the type V receptor appeared not to phosphorylate peptide SEATE (SKDIGSEATEDQAMEDKKK) in which an alanine residue replaced 1 of the 2 close serine residues (at the C-terminal side) of peptide SESTE. These results suggest that the type V receptor is capable of exerting interdependent phosphorylation.

Idiopathic recurrent branch retinal arterial occlusion. Natural history and laboratory evaluation

PURPOSE

To investigate the long-term visual and systemic prognosis of patients with idiopathic recurrent branch retinal artery occlusions, and to test recent hypotheses regarding possible causes of this syndrome.

METHODS

The authors retrospectively reviewed the medical and photographic records of 16 eligible patients. Each of 15 living patients was interviewed by one of the authors, then underwent follow-up ophthalmic examination, formal visual field testing, and a battery of clinical laboratory tests.

RESULTS

Over a mean follow-up of 9 years, only three eyes (9%) lost visual acuity from foveal ischemia, although nine eyes (28%) had central and/or extensive peripheral visual field loss at final examination. Ocular neovascular complications developed in eight eyes (25%). Eight patients (50%) had associated vestibuloauditory and/or transient sensorimotor symptoms, but serious permanent neurologic deficits or recurrent systemic thromboembolic events did not develop. Although most patients had one or more vaso-occlusive risk factors, extensive laboratory testing failed to define the etiology of the arterial occlusions.

CONCLUSIONS

On long-term follow-up, the visual, neurologic, and systemic prognosis for most patients with idiopathic recurrent branch retinal arterial occlusions remains favorable. Although it is probable that such patients are etiologically heterogeneous, the authors theorize that many have mild or partial manifestations of the microangiopathic syndrome of encephalopathy, hearing loss, and retinal arteriolar occlusions.

The major acidic fibroblast growth factor (aFGF)-stimulated phosphoprotein from bovine liver plasma membranes has aFGF-stimulated kinase, autoadenylylation, and alkaline nucleotide phosphodiesterase activities

The major acidic fibroblast growth factor (aFGF)-stimulated phosphoprotein (MAFP) purified from bovine liver exhibits kinase, autoadenylylation, and alkaline nucleotide phosphodiesterase activities depending upon reaction conditions. In the presence of divalent ions, MAFP showed intrinsic and a FGF-stimulated kinase activities (autophosphorylation) using either [gamma-32P]ATP or [gamma-32P]GTP as a substrate. The autophosphorylation activity of MAFP was stimulated at low concentrations of Ca2+, Mg2+, or Mn2+ (0.2-2 microM). Depletion of the divalent ions by EDTA abolished the autophosphorylation activity but enhanced the autoadenylylation activity of MAFP. [alpha-32P]ATP as well as [alpha-32P]NAD could serve as substrates for autoadenylylation activity of MAFP. aFGF appeared to enhance the autoadenylylation activity of MAFP with an optimal concentration (0.6-1.2 nM). P1, P3-di(adenosine-5')-triphosphate (AP3A) was found to be a potent inhibitor for the autophosphorylation and autoadenylylation activities of MAFP. Analyses by automated Edman degradation of the adenylylated and phosphorylated peptides derived from autoadenylylated and autophosphorylated MAFP revealed that both autoadenylylation and autophosphorylation occurred at residue Thr204. The kinase and autoadenylylation activities of MAFP had an optimal pH of 6.9-7.4. However, at pH 8.9, MAFP showed intrinsic and aFGF-stimulated phosphodiesterase activities. aFGF appeared to stimulate the phosphodiesterase activity of MAFP without altering the Km (approximately 0.2 mM) of its substrate.

Bacterial endophthalmitis following cataract surgery in an eye with a preexisting Molteno implant

We describe a patient with a preexisting, functioning Molteno implant in whom acute endophthalmitis developed following cataract extraction. The condition was treated successfully without removing the implant.