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.

Transforming growth factor beta (TGF-beta) type V receptor has a TGF-beta-stimulated serine/threonine-specific autophosphorylation activity

The transforming growth factor beta (TGF-beta) type V receptor, a newly identified high molecular weight TGF-beta receptor (M(r) approximately 400,000) has been purified from bovine liver plasma membranes (O'Grady, P., Kuo, M.-D., Baldassare, J. J., Huang, S. S., and Huang, J. S. (1991) J. Biol. Chem. 266, 8583-8589). The purified TGF-beta type V receptor underwent autophosphorylation at serine residues when incubated with [gamma-32P]ATP in the presence of 0.1% beta-mercaptoethanol and 2.5 mM MnCl2. This phosphorylation was stimulated by preincubation with TGF-beta. The preferred exogenous substrate for the Ser/Thr-specific phosphorylation activity of the type V receptor was found to be bovine casein. The TGF-beta type V receptor could be affinity-labeled with 5'-p-[adenine-8-14C]fluorosulfonylbenzoyl adenosine. Polylysine appeared to stimulate the autophosphorylation of the TGF-beta type receptor in the presence of [gamma-32P]ATP and the incorporation of 5'-p-[adenine-8-14C]fluorosulfonylbenzoyl adenosine into the TGF-beta type V receptor. The amino acid sequence analysis of the peptide fragments produced by cyanogen bromide cleavage of the purified TGF-beta type V receptor revealed that a peptide, namely CNBr-19, contained an amino acid sequence which shows homology to the putative ATP binding site of the receptors for activin, the Caenorhabditis elegans daf-1 gene product, and TGF-beta type II receptor (Lin, H. Y., Wang, Y.-F., Ng-Eaton, E., Weinberg, R. A., and Lodish, H. F. (1992) Cell 68, 775-785). These results suggest that the TGF-beta type V receptor is a Ser/Thr-specific protein kinase and belongs to the new class of membrane receptors associated with a Ser/Thr-specific protein kinase activity.

Purification and characterization of the neu/erb B2 ligand-growth factor from bovine kidney

A neu/erb B2 ligand growth factor (NEL-GF) was purified to homogeneity from bovine kidney by a procedure involving ammonium sulfate fractionation (35-70% saturation) followed by sequential column chromatography on DEAE-cellulose (DE52), Sulfadex (sulfated Sephadex G-50), heparin-Sepharose 4B, and Superdex 75 (fast protein liquid chromatography). NEL-GF was found to be a 25-kDa polypeptide according to the analysis by gel filtration on Superdex 75 and 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. NEL-GF stimulated the tyrosine-specific autophosphorylation of the neu/erb B2 gene product purified by immunoabsorbent and tyrosine-specific phosphorylation of the neu/erb B2 gene product in intact dihydrofolate reductase (DHFR/G-8 cells (NIH 3T3 cells transfected with rat c-neu). NEL-GF also down-regulated the cell surface neu/erb B2 gene product in DHFR/G-8 cells. NEL-GF was mitogenic toward NIH 3T3 cells, DHFR/G-8 cells, A431 cells (human epidermoid carcinoma cells), and SK-BR-3 cells (human breast carcinoma cells) but inactive toward bovine aorta endothelial cells. NEL-GF was sensitive to 0.1% trifluoroacetic acid but resistant to 5% beta-mercaptoethanol and appeared to be distinct from a neu protein-specific activating factor (Davis, J. G., Hamuro, J., Shim, C. Y., Samanta, A., Greene, M. I., and Dobashi, K. (1991) Biochem. Biophys. Res. Commun. 179, 1536-1542) and a 30-kDa glycoprotein which competed with a monoclonal antibody for binding to the neu/erb B2 gene product (Lupu, R., Colomer, R., Zugmaier, G., Sarup, J., Shepard, M., Slamon, D., and Lippman, M. E. (1990) Science 249, 1552-1555).

Characterization of heparin-binding growth-associated factor receptor on NIH 3T3 cells

Scatchard plot analysis of the binding of 125I-labeled heparin binding cell growth-associated factor (125I-HBGAF) to NIH 3T3 cells revealed a single class of high affinity receptors (-5000/cell) with kd of -0.6 nM. 125I-HBGAF was covalently cross-linked to the cell surface receptor on NIH 3T3 cells with disuccinimidyl suberate (DSS). Two 125I-HBGAF-cross-linked complexes of 170 kDa and 142 kDa were observed on SDS-polyacrylamide gel electrophoresis under reducing and nonreducing conditions. The 125I-HBGAF-cross-linked complex formation was completely abolished in the presence of greater than or equal to 100-fold excess of unlabeled HBGAF but not PDGF, EGF, aFGF, bFGF, or insulin. 125I-HBGAF appeared to undergo rapid internalization and relatively slow degradation following binding to the HBGAF receptor on NIH 3T3 cells. These results suggest that NIH 3T3 cells express a high affinity HBGAF receptor which shows two different estimated molecular masses of -155 kDa and -127 kDa. This high affinity HBGAF receptor was also found to express in other cell types.

Variation of perfluoropropane disappearance after vitrectomy

In complex cases of retinal detachment, perfluoropropane (C3F8) is frequently used after vitrectomy for tamponade of retinal breaks. Results of previous studies of C3F8 disappearance using 10% C3F8 after vitrectomy in human eyes have differed significantly. A wide variation in the decay rate and half life of C3F8 after vitrectomy was observed in eyes that had similar clinical settings and received the same C3F8 concentration (15%, 20%, or 25%). This occurred even in those eyes where there was no change in the geometric contour of the eye after a repeat vitrectomy.

Management of endophthalmitis while preserving the uninvolved crystalline lens

Twelve phakic eyes (11 patients) with culture-positive endophthalmitis were treated without removal of the uninvolved crystalline lens. Eight eyes were treated by pars plana vitrectomy and intraocular injection of antibiotics. Four eyes were treated with intraocular antibiotic injection alone. The clinical infection was successfully eradicated in all patients, including one patient treated with reinjection of antibiotics. During follow-up after successful treatment, eight eyes had progression of a preexisting lens opacification, two eyes had stable lens opacification, and two eyes maintained clear lenses. Six of 12 eyes achieved 20/80 or better visual acuity with an average follow-up time of 13 months. Six of eight eyes treated with pars plana vitrectomy and intraocular antibiotic injection achieved this level of visual acuity in contrast to none of four eyes treated with only intraocular antibiotic injection. These results indicated that endophthalmitis in phakic eyes can be successfully treated while preserving a clear, uninvolved crystalline lens by the use of pars plana vitrectomy and intraocular administration of appropriate antibiotics.

The plasma cell membrane glycoprotein, PC-1, is a threonine-specific protein kinase stimulated by acidic fibroblast growth factor

A 32P-labeled protein that co-purified with acidic fibroblast growth factor (aFGF) receptor from bovine liver proved to be a distinct membrane protein, which itself has kinase activity that is stimulated by aFGF. The protein was designated MAFP for major aFGF-stimulated phosphoprotein. MAFP was purified from bovine liver using immunoaffinity chromatography with monoclonal antibody to MAFP following Triton X-100 extraction of plasma membranes and wheat germ lectin-Sepharose 4B column chromatography. The purified MAFP showed molecular masses of 130 kDa and 260 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing and nonreducing conditions, respectively. Purified MAFP elicited aFGF-stimulated Thr-specific autophosphorylation activity and phosphorylation activity toward protein substrates (myelin basic protein and histone). Amino acid sequence analyses of 16 peptide fragments of MAFP, produced by endoproteinase Lys-C digestion followed by reduction and S-pyridylethylation, showed approximately 80-100% homology with the cDNA-deduced amino acid sequences of human and mouse plasma cell membrane glycoprotein, PC-1 (Buckley, M. F., Loveland, K. A., McKinstry, W. J., Garson, O. M., and Goding, J. W. (1990) J. Biol. Chem. 265, 17506-17511), suggesting that MAFP is the bovine version of PC-1. The amino acid sequences of bovine MAFP, human and mouse PC-1 reveal a putative ATP binding site in their extracellular domains. These results suggest that MAFP(PC-1) is an ectoprotein kinase. In addition to the kinase activity, MAFP(PC-1) was also found to possess alkaline nucleotide phosphodiesterase activity. It is now clear that several of the unique properties previously attributed to the aFGF receptor kinase are actually properties of this novel Thr-specific ectoprotein kinase, which co-purifies with the aFGF receptor and is responsive to stimulation by aFGF.

Presumed Pneumocystis carinii choroiditis. Unifocal presentation, regression with intravenous pentamidine, and choroiditis recurrence

Pneumocystis carinii choroiditis is a well-documented but rare infection that has been described as a bilateral, multifocal process. Treatment efficacy has not been well established. In this report, three cases of presumed P. carinii choroiditis that developed during aerosolized pentamidine therapy for the prophylaxis of P. carinii pneumonia are described. All patients had unilateral choroiditis, and two patients were first observed to have unifocal choroiditis. In all patients, choroidal lesions decreased in size with intravenous pentamidine treatment. Choroiditis exacerbated in the two unifocal cases after the frequency of maintenance intravenous pentamidine therapy was decreased. P. carinii choroiditis may appear as a unifocal, unilateral lesion that may represent an earlier stage of infection than previously described. Intravenous pentamidine therapy appears to control P. carinii choroiditis but may need to be continued to prevent exacerbation. Patients receiving prophylactic aerosolized pentamidine therapy are not protected against extrapulmonary disease, and presumed P. carinii choroiditis may serve as a marker for disseminated infection.

Expression of a new type high molecular weight receptor (type V receptor) of transforming growth factor beta in normal and transformed cells

A new type high molecular weight receptor (type V receptor) of transforming growth factor beta (TGF-beta) was recently purified from bovine liver plasma membranes and appears not to be related to receptors previously described for TGF-beta (Pauline O'Grady, Ming-Der Kuo, Joseph J. Baldassare, Shuan Shian Huang and Jung San Huang [1991] J. Biol. Chem. 266:8583-8589). This type V receptor may be important in the regulation of cell growth by TGF-beta. We examined its distribution in a wide range of normal and transformed cells. The type V receptor was found to be expressed in many normal cells including cells of epithelial, endothelial, fibroblastic and chondrocytic origins. However, a number of human epithelial tumor cells (5 out of 6 examined) did not express detectable levels of the type V TGF-beta receptor. These results suggest that loss of the type V receptor may potentially contribute to the transformed state of certain epithelial tumor cells.

Changes in pulmonary Cu-Zn contents in superior mesenteric artery occlusion shock of rabbit

Contents of Cu and Zn of into-pulmonary blood (IPB), out-pulmonary blood (OPB), Lung tissue, and supernatant and macrophages of Lung Lavage were determined in superior mesenteric artery occlusion (SMAO) shock of rabbits. Zn of pulmonary tissue was 11.42 +/- 0.60 and 14.52 +/- 1.78 (micrograms/g wet wt) in SMAO shock and control groups, respectively. Content of Zn was found to be lower, Cu was not changed, and Cu/Zn ratio increased in lung tissue in SMAO shock. Contents of Cu and Zn in other samples were not changed. The results suggest that lower Zn in lung tissue related to acute lung injury.

Purification of a new type high molecular weight receptor (type V receptor) of transforming growth factor beta (TGF-beta) from bovine liver. Identification of the type V TGF-beta receptor in cultured cells

A 400-kDa transforming growth factor beta (TGF-beta) receptor was purified from plasma membranes of bovine liver using Triton X-100 extraction, wheat germ lectin-Sepharose 4B affinity chromatography, DEAE-cellulose anion exchange chromatography, and Sepharose CL-4B gel filtration chromatography. This procedure yielded approximately 20 micrograms of the receptor from 1 kg of bovine liver. During purification, the 400-kDa TGF-beta receptor was detected by a cross-linking assay in which the TGF-beta receptor-125I-TGF-beta complex was cross-linked by disuccinimidyl suberate, a bifunctional reagent, and analyzed by 5.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by autoradiography. This novel 400-kDa TGF-beta receptor was also identified on cultured cells including cells reported to lack the type III receptor. The 400-kDa TGF-beta receptor, a nonproteoglycan glycoprotein, appears to be distinct from TGF-beta receptors (types I, II, III, and IV) previously identified on cultured cells and is designated as the type V receptor. The 400-kDa TGF-beta receptor as well as type I, II, and III receptors underwent internalization upon 125I-TGF-beta binding in mink lung epithelial cells.