Isolated right ventricular dysfunction in systemic sclerosis: latent pulmonary hypertension?

Right ventricular function is frequently abnormal in patients with systemic sclerosis, but whether this is related to pulmonary vascular complications of the disease is unclear. Standard echocardiography with tissue Doppler imaging was performed at rest and during exercise for the study of right ventricular function and pulmonary circulation in 25 consecutive systemic sclerosis patients and in 13 age-matched healthy controls. When compared with the controls, the patients had no difference in systolic right ventricular pressure gradient, but a decreased pulmonary flow acceleration time, and increased right ventricular free wall thickness and end-diastolic dimensions. At the tricuspid annulus, the E maximal velocity was decreased (8.9 +/- 4 versus 11.7 +/- 2.3 cm.s(-1)) and the isovolumic relaxation time corrected to RR interval was increased (6.5 +/- 2.9 versus 4.5 +/- 2.5%). The tissue Doppler imaging profile at the mitral annulus was similar in both groups. At exercise, 18 patients had a decreased maximum workload and cardiac output, no change in systolic right ventricular pressure gradient, but an increase in the slope of pulmonary artery pressure/flow relationships. These results suggest that patients with systemic sclerosis may present with latent pulmonary hypertension as a likely cause of right ventricular diastolic dysfunction, as revealed by stress echocardiography and tissue Doppler imaging.     

Identification and characterization of linear B-cell epitopes of beta-globulin, a major allergen of sesame seeds

BACKGROUND: The increased consumption of foods containing sesame seeds is paralleled by an increase in reported sesame-induced allergic reactions. OBJECTIVE: This study aimed at identifying and characterizing the linear B-cell epitopes of the 14-kd beta-globulin, the major allergen of sesame seed. METHODS: A peptide containing 71 amino acids (peptide B) was previously identified by us as the IgE-binding region on beta-globulin. To determine the amino acid sequence of the IgE-binding sites on peptide B, we synthesized overlapping peptides 20 and 10 amino acid residues long that span the entire length of peptide B, which were offset from each other by 10 and 2 amino acid residues, respectively. Sera from 20 subjects given diagnoses of allergy to sesame beta-globulin served to identify the epitopes by using the dot-blot test. RESULTS: At least 9 different IgE-recognition sites were identified on peptide B. Three of them, numbers 2, 3, and 13 (corresponding to amino acids 46-55, 48-57, and 76-86, respectively, in the beta-globulin sequence), appeared to be immunodominant IgE-binding epitopes. Also, these peptides were best recognized in terms of intensity of response. There was no obvious sequence motif shared by the 9 different IgE-binding epitopes of beta-globulin. However, approximately 60% of the amino acids represented in the epitopes are hydrophobic residues. CONCLUSION: Identification of the IgE-binding epitopes might provide a better understanding of the functional role the allergens play in the disease and might have implications for immunodiagnosis and probably immunotherapy.     

Two-pulse monocular and binocular interactions at the differential luminance threshold

Interaction between two pulses at the differential luminance threshold was studied for stimuli pairs presented to the same eye or to opposite eyes with an interocular delay. With monocular stimuli, the results replicated the earlier observations by Ikeda (1965) and Rashbass (1970) indicating linear interaction followed by rectification occurring at about 50-60 msec into the integration epoch. Binocular results were different, in accord with observations made in the contrast domain by Green and Blake (1981). Binocular stimuli of opposite polarity showed no cancellation. Binocular facilitation at threshold was found when either the stimuli of the same sign (+ + or - -) occurred with little interocular delay (stimulus onset asynchrony, SOA less than 15 msec), or the stimuli of the opposite sign (+ - or - +) were presented with an interocular delay between 15 and 100 msec SOA; the latter effect was at maximum with flashes 50 msec in duration presented with 50 msec interocular SOA. These results imply that binocular interaction takes place between rectified internal effects of luminance pulses. From the two-channel binocular model of Cogan (1987), binocular facilitation is attributed to the "fused" response derived from multiplicative excitation between same-sign (half-wave rectified), internal pulse responses. The absence of cancellation between simultaneous opposite-sign dichoptic stimuli is attributed to the "either-eye" binocular process dealing with full-wave rectified internal pulse responses to transient stimuli.     

Relationship between smoking, dietary intakes and plasma levels of vitamin E and beta-carotene in matched maternal-cord pairs.

The concentrations of tocopherols and carotenoids are lowered in umbilical cord blood plasma, which may have a negative effect on antioxidant protection in neonates. Smoking may adversely affect dietary intakes and plasma concentrations of carotenoids. The dietary intakes of vitamin E and beta-carotene were assessed in 66 pregnant women (31 smokers and 35 non-smokers) between 10 and 20 weeks gestation using a food frequency questionnaire. The concentrations of alpha-tocopherol and beta-carotene were measured in maternal plasma at the time of the dietary assessment, and in the matched umbilical cords of their newborn after delivery. In smoking and non-smoking mothers, the mean intakes of vitamin E (9.3 [SD 5] and 8.2 [SD 5] mgd-1) and beta-carotene (3464 [SD 1885] and 2977 [SD 1503] micrograms d-1) were not significantly different. The plasma concentrations of alpha-tocopherol (20.8 [SD 4] and 20.5 [SD 4] mumol L-1), the alpha-tocopherol to lipid ratios (3.2 [SD 0.8] and 3.5 [SD 0.8]) and the plasma concentrations of beta-carotene (0.22 [SD 0.1] and 0.22 [SD 0.1] mumol L-1) were not significantly different in smoking and non-smoking mothers. There were no significant differences in plasma alpha-tocopherol (7.4 [SD 2] and 7.3 [SD 2] mumol L-1), in alpha-tocopherol to lipid ratios (3.2 [SD 0.6] and 2.8 [SD 0.6]) or in beta-carotene concentrations (0.05 [SD 0.04] and 0.03 [SD 0.02] mumol L-1) in cords from newborns of smoking and non-smoking mothers. There was a significant correlation (r = 0.41, P = 0.015) between dietary intakes and plasma concentrations of beta-carotene in non-smoking mothers. However, this relationship was not significant in smoking mothers (r = 0.28, P = 0.12). There were no relationships between dietary intakes and plasma concentrations of tocopherol. These results indicate that smoking during pregnancy does not appear to affect the dietary intakes or plasma concentrations of alpha-tocopherol and beta-carotene in pregnant women or their babies. However, smoking does influence the relationship between dietary intakes and plasma levels of beta-carotene.     

Evaluation of a Thin-film Peripheral Nerve Cuff Electrode

Abstract

This is a study of the reaction of large nerves to implantation using a flexible, thin-film cuff electrode. Cuff electrodes were implanted on the sciatic nerve of three cats. An implantation period of six weeks allowed sufficient time for any injury responses in the nerve and connective tissue sheath around the cuff to develop. The electrode came off the nerve in one of the cats. In the remaining two cats, gross observation following explantation of the electrodes revealed encapsulation of the cuffs without swelling of nerve tissue. Histological evaluation did not demonstrate nerve injury. The nerve cuff electrodes, which are comprised of titanium and iridium coatings on a fluorocarbon polymer substrate, appeared unaffected by the implantation, and connective tissue encapsulation did not adhere to either the polymer substrate or metallization. Evaluation of the electrodes using activated iridium oxide charge injection sites in more extended studies is now being undertaken. (J Spinal Cord Med; 18:28–32)     

NIH conference. Aldose reductase and complications of diabetes

Tissues of the eye affected by diabetes are the lens, cornea, and retina. The lens becomes cataractous through osmotic swelling of its cortical fibers. Sorbitol, formed in the presence of aldose reductase, accumulates in the lens during hyperglycemia. Dulcitol similarly accumulates in the presence of galactosemia. Cataractogenesis in both cases can be prevented by inhibitors of aldose reductase. The efficacy of synthetic inhibitors differs in various tissues and species, but they react with aldose reductase at a common structural site. The most promising inhibitor is sorbinil . Diabetic retinopathy is similarly related to sorbitol accumulation and may be prevented or reversed by inhibition of aldose reductase. Healing of corneal wounds in diabetes is facilitated by enzyme inhibition. Retinal vasculopathy of diabetes is due to selective loss of the intramural pericytes that normally form structural elements in the retinal capillary walls. The vulnerability of these cells is due to their aldose reductase content. Whether inhibition of aldose reductase will prevent retinopathy is being tested in a randomized trial conducted by the National Eye Institute.     

Primary systemic amyloidosis presenting with advanced heart failure

Primary systemic amyloidosis (AL) is a rare, sporadic disease caused by deposition of immunoglobulin light chains in various tissues; symptoms vary based on which organs are infiltrated by the amyloid fibrils. Cardiac involvement occurs in up to 50% of patients with primary amyloidosis and is associated with a very poor prognosis. We report a case of a 57-year-old black man who presented with symptoms consistent with congestive heart failure. He was later found to have primary systemic amyloidosis, confirmed by abdominal fat pad biopsy.