Surgical treatment of thoracic deformity in Poland's syndrome

In 1841, Poland described congenital deficiency of the pectoralis major and minor muscles associated with syndactyly. This syndrome is a spectrum, often involving chest wall and breast deformity as well. Identification of the various musculoskeletal components involved permits optimal thoracic reconstruction in the small proportion of patients who will require it. From 1955 to 1988, 75 patients (40 males and 35 females) with Poland's syndrome were treated or evaluated. Patients with isolated deficiencies of the pectoral muscles, breast, or hand deformity were excluded. The complex was right-sided in 44 patients, left-sided in 30, and bilateral in one. The pectoralis minor and the costal portion of the pectoralis major muscle were absent in all patients. Hand anomalies were present in 50 patients. Athelia and/or amastia were noted in 37 patients. In ten patients, the rib cage deformity required reconstruction, and in three cases, rib or cartilage grafts were needed for complete repair. Often unappreciated in these cases is the significant rotation of the sternum toward the involved side and contralateral carinate deformity. Correction is achieved by bilateral subperichondrial costal cartilage resection and sternal osteotomy (seven of ten patients), thus allowing anterior displacement and orthorotation of the sternum. Chest wall reconstruction must be tailored to the requirements of each patient. No intraoperative or postoperative complications occurred in these ten patients. In males without rib cage deformity, generally no treatment is required to replace the absent pectoral muscles, although in two cases rotation of the latissimus dorsi muscle was performed. In all females, reconstruction of the ipsilateral breast is required at full development.(ABSTRACT TRUNCATED AT 250 WORDS)     

HMO enrollment and Medicaid. Survival analysis with a Weibull function

This paper analyzes the length of enrollment in Health Maintenance Organizations (HMOs) by performing secondary data analysis. It estimates a Weibull survival function using only simple regression. For middle-class enrollees in one HMO, the hazard rate (the disenrollment rate for the remaining members of a cohort) falls sharply with the length of enrollment. For medicaid beneficiaries allowed to remain in the fee-for-service sector, the hazard rate in another HMO is much greater but falls less sharply. Limiting the choice of Medicaid beneficiaries to HMOs would increase their length of enrollment, lowering a major barrier to HMOs' participation in Medicaid.     

Evaluation of ocular protection filters in field situations

A computer program has been developed to simulate eye movement during pursuit tracking to test the effectiveness of filters protecting the eyesight of individuals exposed to laser radiation. Two types of retinal damage are considered: macular lesions and retinal injury causing vitreous or subretinal hemorrhage. The retinal damage caused by optical radiation in the visible and near infrared of the spectrum differs from almost all other types of hazards in their proabilistic nature. That is, a small movement of the laser beam or change of eye position decreases or increases the probability of injury by several orders of magnitude. A laser beam combines the problem of a small source with extreme directionality with the probabilistic nature of this hazard location in space, and we now add the probabilistic nature of the action of the protective filter, i.e., a dependence upon angle of incidence. From this combination, an even more probabilistic picture of injury or disablement emerges. When it is necessary to plan the probabilities during military operations of mission fulfillment or injury with regard to various types of lasers in the battlefield ++environment, the problem must be analyzed very carefully. Our solution of the problem indicates the type of injuries to be expected and their dependence upon the various parameters of the angle of incidence of the lasers on the protective filters in the viewing system.     

Bioavailability of and interactions between zinc and selenium in rats fed wheat grain intrinsically labeled with 65Zn and 75Se

A whole-body radioassay procedure was used to assess the absorption by male rats of zinc (Zn) and selenium (Se) in wholewheat grain labeled either intrinsically or extrinsically with 65Zn and 75Se. Test meals fed to zinc-depleted and to zinc-adequate rats contained grain harvested from plants grown in nutrient solutions with varying amounts of zinc and selenium. Absorption of intrinsic 65Zn by zinc-depleted rats ranged from about 46 to 57% of the dose, and 65Zn absorption decreased as the selenium content of the grain increased. Absorption of intrinsic 65Zn by zinc-adequate rats ranged from about 21 to 26% of the dose, and 65Zn absorption was not affected by the amount of either zinc or selenium in the meal. Absorption of intrinsic 75Se ranged from about 43 to 52% of the dose in zinc-depleted rats and from about 35 to 48% of the dose in zinc-adequate rats. Absorption of intrinsic 75Se by zinc-adequate rats decreased as the zinc content of the grain increased. Relative to the absorption and retention by rats of intrinsic zinc and selenium in wholewheat grain, interactions occurred between natural forms of zinc and selenium at concentrations potentially encountered in wheat. Selenium had an antagonistic effect on zinc absorption by zinc-depleted rats, and zinc had an antagonistic effect on selenium absorption by zinc-adequate rats.     

Modulating role for thromboxane in the tubuloglomerular feedback response in the rat.

Some studies have indicated that PGs can modulate the single nephron tubuloglomerular feedback (TGF) response. The aim of this study was to define the specific role of the vasoconstrictor PG, TX, by administration to rats of either vehicle (group 1; n = 20) or drugs that inhibit either cyclooxygenase (indomethacin [indo], 5 mg.kg-1, group 2, n = 17), TX synthetase (UK-38,485 [UK], 100 mg.kg-1, group 3, n = 19), or TX receptors (SQ-29,548 [SQ], 8 mg.kg-1, group 4, n = 14, or L-641,953 [L], 50 mg.kg-1, group 5, n = 8). Indo reduced excretion of the prostacyclin derivative 6-keto-PGF1 alpha and TXB2 and lowered whole kidney GFR and renal plasma flow, whereas UK lowered excretion of TXB2 only and did not change basal renal hemodynamics. The TGF response (assessed from reduction in proximal tubule stop-flow pressure (Psf, mmHg) during increases in perfusion of the loop of Henle (LH) from 0 to 40 nl.min-1) was unchanged after vehicle (9.8 +/- 0.5-10.9 +/- 1.0, NS) but blunted (P less than 0.001) by 40-65% in rats of groups 2-5 (indo, 11.1 +/- 1.0-4.4 +/- 0.7; UK, 9.0 +/- 0.8-4.8 +/- 0.7; SQ, 10.3 +/- 0.6-4.8 +/- 0.6; L, 10.7 +/- 0.5-6.7 +/- 1.3). This blunting was due to lower values for Psf at zero LH flow after indo, SQ, and L, and higher values of Psf at 40 nl.min-1 LH flow after indo and UK. The fall in single nephron GFR (SNGFR, nl.min-1) with increasing LH perfusion was unchanged after vehicle (10.9 +/- 2.8-11.2 +/- 0.8) but was blunted (P less than 0.05) by 45-55% in rats given indo (13.9 +/- 1.2-6.2 +/- 2.2) or UK (12.8 +/- 2.1-7.0 +/- 1.5). UK produced dose-dependent reductions in TXB2 excretion (IC50, 15 mg.kg-1) and inhibition of the TGF response (IC50: 30 mg.kg-1). After blockade of TX receptors by SQ, UK had no further affect on the TGF response. The fall in Psf at high LH flow was blunted (P less than 0.05) by indo and UK, whereas the rise in Psf at zero LH flow was blunted by indo, SQ, and L. In conclusion, endogenous TX generation can modulate the reductions in Psf and SNGFR during increased delivery of NaCl to the LH.     

Steroids and their conjugates in the mammalian brain.

Five steroids--3 beta-hydroxypregn-5-en-20-one (pregnenolone; P), 3 beta-hydroxy-5 alpha-pregnan-20-one (3 beta-AP), 3 alpha-hydroxy-5 alpha-pregnan-20-one (3 alpha-AP), 3 beta-hydroxyandrost-5-en-17-one (dehydroepiandrosterone; D), and 3 beta-hydroxy-5 alpha-androstan-17-one (EpiA)--were extracted from the brains of adult male rats, rabbits, and dogs. The steroids exist in this organ as unconjugated compounds and as sulfates, lipoidal esters, and sulfolipids. The techniques for separating these four classes of steroids from each other and for separating the five steroids from each other are described. In all cases, the steroids were identified by their retention time (Rt) on HPLC, their Rt by gas chromatography, and by selected ion monitoring of their mass spectra. The latter were also used for quantification. In their reaction toward organic bases, the sulfolipid conjugates resemble previously described sulfolipids of cholesterol and sitosterol. These conjugates are relatively abundant in brain, particularly those of P and D, and this suggests that, in the search for the physiological significance of these brain constituents, these conjugates warrant attention.     

Whole blood platelet function in acute ischemic stroke. Importance of dense body secretion and effects of antithrombotic agents

We studied platelet function in whole blood, a situation that better reflects the in vivo state, from 85 patients with acute ischemic stroke and from 19 healthy controls. Patients receiving no antithrombotic drugs demonstrated increased platelet dense body secretion without an associated increase in platelet aggregation, thus raising the possibility that dense body secretion may be of separate importance in cerebral infarction. Our results also suggest that dense body secretion may occur independently of aggregation. Heparin and heparin plus warfarin were ineffective in reducing the high level of dense body secretion seen in acute cerebral infarction, whereas treatment with aspirin plus dipyridamole inhibited both dense body secretion and platelet aggregation. It seems worthwhile to investigate the usefulness of antiplatelet drugs in the treatment of acute ischemic stroke wherein clinical outcome is correlated with the extent of suppression of platelet dense body secretion.     

Correlation of the interpretation of fetal heart rate records with cord plasma erythropoietin levels

On the basis that fetal levels of plasma erythropoietin (Ep) may reflect fetal oxygenation the primary purpose of the present study was to assess the relation between Ep measured in cord plasma at delivery and the intrapartum fetal heart rate (FHR) record. A scoring system for interpreting FHR recordings blindly was prospectively utilized in 41 selected human pregnancies during the 4 h immediately preceding birth. The correlation of the overall mean FHR score for each individual patient with cord plasma Ep was significant such that the highest Ep levels were observed in those infants with the most abnormal FHR scores. Furthermore, when the birthweights of the infants were adjusted for gestational age, sex, and birth order, birthweight centile was negatively correlated with cord plasma Ep. When both FHR score and birthweight were simultaneously correlated with cord plasma Ep using multiple regression, the combined effect of these two factors improved the association of either alone with both contributing approximately equally.