Severe aortic regurgitation with mechanical prosthetic valve replacement in pauciarticular juvenile rheumatoid arthritis

We describe a patient with pauciarticular juvenile rheumatoid arthritis with aortic insufficiency who underwent successful aortic valve replacement with a mechanical prosthetic valve.     

Complexation Behavior of Polyampholytes and Charged Objects

We study theoretically the interaction of a polyampholyte chain with charged planes, cylinders, and spheres. Due to the random character of the charge distribution along the chain, a polyampholyte possesses a spontaneous dipole moment, which can interact favorably with charged objects. Depending on the charge strength of the object and the polyampholyte length and fraction of charged monomers, this attractive interaction can be strong enough to induce adsorption. The addition of salt weakens the trend to adsorption, but proves necessary to adsorb polyampholytes of the same net charge as the charged object in the case of planes and cylinders. Long polyampholytes form globules, for which the number of uncompensated charges and thus the spontaneous dipole moment is reduced. Nevertheless, globules can adsorb on charged objects via two pathways: they either adsorb as a whole, (intact globule), or they are dissolved into a coil state prior to adsorption. Applications to the complexation behavior of polyampholytes with stiff, rodlike polyelectrolytes and with charged microspheres or charged spherical micelles are given.     

Isolation and stability of histidine-tagged proteins produced in plants via potyvirus gene vectors

A system for the expression and purification of histidine-tagged proteins from plants has been developed using a tobacco etch potyvirus (TEV)-derived gene vectors. The vectors offered a convenient polylinker and a choice of histidine tagging at the recombinant proteins' N or C termini. These vectors were utilized for expression of proteins encoded by beet yellows closterovirus (BYV). Approximately 4 micrograms/g of 20-kDa BYV protein was readily isolated from plants systemically infected by hybrid TEV. In contrast, only minute quantities of 22-kDa BYV capsid protein (CP) histidine-tagged at its N or C terminus could be purified. Rapid degradation of the recombinant CP has been implicated in its failure to accumulate in infected plants. Fusion with TEV HC-Pro stabilized the histidine-tagged BYV CP and facilitated purification of the fusion product from infected plants. This same fusion approach was successfully used with the 24-kDa minor BYV CP. The recombinant proteins were recognized by histidine-tag-specific monoclonal antibody in immunoblot analysis. These results demonstrate the utility of a designed series of TEV vectors for expression, detection, and purification of the recombinant proteins and suggest that intrinsic protein stability is a major factor in a recovery of recombinant proteins from plants.     

Autocrine inhibition of the epidermal growth factor receptor by intracellular expression of a single-chain antibody

A gene encoding a single-chain antibody which specifically binds the human epidermal growth factor (EGF) receptor has been constructed and expressed intracellularly. The single-chain antibody is derived from monoclonal antibody 225 which competes with EGF for binding to the extracellular domain of the receptor. The single-chain antibody was provided with a signal peptide to direct it to the secretory pathway and was expressed in EGF receptor transformed NIH/3T3 fibroblasts. EGF induced activation of its receptor was reduced in these cells. In addition, EGF-induced anchorage-independent growth of the cells was inhibited. The data suggest that the single-chain antibody functions in an autocrine fashion to inhibit the activity of the EGF receptor.     

Follow-up of argon laser trabeculoplasty: is a day-one postoperative IOP check necessary?

BACKGROUND AND OBJECTIVES: To evaluate the benefit of measuring the intraocular pressure (IOP) on the first postoperative day after argon laser trabeculoplasty (ALT). PATIENTS AND METHODS: We retrospectively reviewed 407 ALT procedures with perioperative apraclonidine performed on 226 patients between January 1991 and December 1993. Data analyzed included type of glaucoma, extent of treatment, whether the procedure was initial or repeat, laser parameters, and IOP preoperatively and at 1 hour, 1 day, and 1 month postoperatively. RESULTS: The percentage of patients with an IOP rise of greater than 3 mm Hg at 1 hour, 1 day, and 1 month following ALT was 11.3%, 4.2%, and 5.2% respectively. The incidence of IOP elevations greater than 10 mm Hg was 2.2%, 1.0%, and 1.5% at 1 hour, 1 day and 1 month, respectively. Of 17 cases with an IOP elevation greater than 3 mm Hg at 1 day, four eventually required a trabeculectomy. However, there were no consistent factors that distinguished which cases with elevated IOP at 1 day ultimately needed further therapy, nor did the 1-day postoperative examination predict which patients would have IOP elevation at 1 month. CONCLUSION: IOP 1 day after ALT is rarely elevated and does not correlate with IOP elevation at 1 month. Therefore, an IOP check at 1 day is not felt to be necessary for most patients.     

Migration of human keratinocytes in electric fields requires growth factors and extracellular calcium

Currents that leak out of wounds generate electric fields lateral to the wound. These fields induce directional locomotion of human keratinocytes in vitro and may promote wound healing in vivo. We have examined the effects of growth factors and calcium, normally present in culture medium and the wound fluid, on the directional migration of human keratinocytes in culture. In electric fields of physiologic strength (100 mV per mm), keratinocytes migrated directionally towards the cathode at a rate of about 1 microm per min. This directional migration requires several growth factors. In the absence of these growth factors, the cell migration rate decreased but directionality was maintained. Epidermal growth factor alone restored cell migration rates at concentrations as low as 0.2 ng per ml. Insulin at 5-100 microg per ml or bovine pituitary extract at 0.2%-2% vol/vol also stimulated keratinocyte motility but was not sufficient to fully restore the migration rate. Keratinocyte migration in electric fields requires extracellular calcium. Changes in calcium concentrations from 3 microM to 3.3 mM did not significantly change keratinocyte migration rate nor directionality in electric fields; however, addition of the chelator ethyleneglycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid to migration medium reduced, and eventually abolished, keratinocyte motility. Our results show that (i) growth factors and extracellular calcium are required for electric field-induced directional migration of human keratinocytes, and (ii) keratinocytes migrate equally well in low and high calcium media.     

The Veterans Affairs Implantable Insulin Pump Study: effect on cardiovascular risk factors

OBJECTIVE: To determine whether implantable insulin pump (IIP) and multiple-dose insulin (MDI) therapy have different effects on cardiovascular risk factors in insulin-requiring patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: A randomized clinical trial was conducted at seven Veterans Affairs medical centers in 121 male patients with type 2 diabetes between the ages of 40 and 69 years receiving at least one injection of insulin per day and with HbA1c, levels of > or =8% at baseline. Weights, blood pressures, insulin use, and glucose monitoring data were obtained at each visit. Lipid levels were obtained at 0, 4, 8, and 12 months, and free and total insulin levels were obtained at 0, 6, and 12 months. All medications being taken were recorded at each visit. RESULTS: No difference in absolute blood pressure, neither systolic nor diastolic, was seen between patients receiving MDI or IIP therapy, but significantly more MDI patients required anti-hypertensive medications. When blood pressure was modeled against weight and time, IIP therapy was significantly better than MDI therapy for systolic blood pressure in patients with BMI <33 and for diastolic blood pressure in patients with BMI >34 kg/m2. Total cholesterol levels decreased in the overall sample, but IIP patients exhibited significantly higher levels than MDI patients. Triglyceride levels increased over time for both groups, with IIP patients having significantly higher levels than patients in the MDI group. BMI was a significant predictor of, and inversely proportional to, HDL cholesterol level. No difference in lipid-lowering drug therapy was seen between the two groups. Free insulin and insulin antibodies tended to decrease in the IIP group as compared with the MDI group. C-peptide levels decreased in both groups. CONCLUSIONS: IIP therapy in insulin-requiring patients with type 2 diabetes has advantages over MDI therapy in decreasing the requirement for antihypertensive therapy and for decreasing total and free insulin and insulin antibodies. Both therapies reduce total cholesterol and C-peptide levels.     

Increased MPTP neurotoxicity in vesicular monoamine transporter 2 heterozygote knockout mice

The neurotoxic action of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been proposed to be attenuated by sequestration into intracellular vesicles by the vesicular monoamine transporter (VMAT2). The purpose of this study was to determine if mice with genetically reduced levels of VMAT2 (heterozygote knockout; VMAT2 +/-) were more vulnerable to MPTP. Striatal dopamine (DA) content, the levels of DA transporter (DAT) protein, and the expression of glial fibrillary acidic protein (GFAP) mRNA, a marker of gliosis, were assessed as markers of MPTP neurotoxicity. In all parameters measured VMAT2 +/- mice were more sensitive than their wild-type littermates (VMAT2 +/+). Administration of MPTP (7.5, 15, or 30 mg/kg, b.i.d.) resulted in dose-dependent reductions in striatal DA levels in both VMAT2 +/- and VMAT2 +/+ animals, but the neurotoxic potency of MPTP was approximately doubled in the VMAT2 +/- mice: 59 versus 23% DA loss 7 days after 7.5 mg/kg dose for VMAT2 +/- and VMAT2 +/+ mice, respectively. Dopaminergic nerve terminal integrity, as assessed by DAT protein expression, also revealed more drastic reductions in the VMAT2 +/- mice: 59 versus 35% loss at 7.5 mg/kg and 95 versus 58% loss at 15 mg/kg for VMAT2 +/- and VMAT2 +/+ mice, respectively. Expression of GFAP mRNA 2 days after MPTP was higher in the VMAT2 +/- mice than in the wild-type: 15.8- versus 7.8-fold increase at 7.5 mg/kg and 20.1- versus 9.6-fold at 15 mg/kg for VMAT2 +/- and VMAT2 +/+ mice, respectively. These observations clearly demonstrate that VMAT2 +/- mice are more susceptible to the neurotoxic effects of MPTP, suggesting that VMAT2-mediated sequestration of the neurotoxin into vesicles may play an important role in attenuating MPTP toxicity in vivo.     

Cycloalkylpyranones and cycloalkyldihydropyrones as HIV protease inhibitors: exploring the impact of ring size on structure-activity relationships

Previously, 3-substituted cycloalkylpyranones, such as 2d, have proven to be effective inhibitors of HIV protease. In an initial series of 3-(1-phenylpropyl) derivatives with various cycloalkyl ring sizes, the cyclooctyl analog was the most potent. We became interested in exploring the influence of other structural changes, such as substitution on the phenyl ring and saturation of the 5,6-double bond, on the cycloalkyl ring size structure-activity relationship (SAR). Saturation of the 5,6-double bond in the pyrone ring significantly impacts the SAR, altering the optimal ring size from eight to six. Substitution of a sulfonamide at the meta position of the phenyl ring dramatically increases the potency of these inhibitors, but it does not change the optimal ring size in either the cycloalkylpyranone or the cycloalkyldihydropyrone series. This work has led to the identification of compounds with superb binding affinity for the HIV protease (Ki values in the 10-50 pM range). In addition, the cycloalkyldihydropyrones showed excellent antiviral activity in cell culture, with ED50 values as low as 1 microM.     

Two linear acetogenins from Goniothalamus gardneri

Two new acetogenins, gardnerilins A and B, have been isolated from the roots of Goniothalamus gardneri. Both are C35 acetogenins containing non-tetrahydrofuran rings. Their structures have been established on the basis of spectral evidence.