A unified framework for constructing, tuning and assessing photometric redshift density estimates in a selection bias setting

Photometric redshift estimation is an indispensable tool of precision cosmology. One problem that plagues the use of this tool in the era of large-scale sky surveys is that the bright galaxies that are selected for spectroscopic observation do not have properties that match those of (far more numerous) dimmer galaxies; thus, ill-designed empirical methods that produce accurate and precise redshift estimates for the former generally will not produce good estimates for the latter. In this paper, we provide a principled framework for generating conditional density estimates (i.e. photometric redshift PDFs) that takes into account selection bias and the covariate shift that this bias induces. We base our approach on the assumption that the probability that astronomers label a galaxy (i.e. determine its spectroscopic redshift) depends only on its measured (photometric and perhaps other) properties [Formula: see text] and not on its true redshift. With this assumption, we can explicitly write down risk functions that allow us to both tune and compare methods for estimating importance weights (i.e. the ratio of densities of unlabelled and labelled galaxies for different values of [Formula: see text]) and conditional densities. We also provide a method for combining multiple conditional density estimates for the same galaxy into a single estimate with better properties. We apply our risk functions to an analysis of ≈10⁶ galaxies, mostly observed by Sloan Digital Sky Survey, and demonstrate through multiple diagnostic tests that our method achieves good conditional density estimates for the unlabelled galaxies.

Embryological background of truncular venous malformation in the extracranial venous pathways as the cause of chronic cerebro spinal venous insufficiency

The truncular venous malformation (VM) represents an embryologically defective vein where developmental arrest has occurred during the vascular trunk formation period in the 'later stage' of the embryonic development. A relatively simple truncular VM lesion such as a venous web at the hepatic venous outlet causes portal hypertension giving a profound damage/impact to the liver. A similar condition involving the head and neck venous system may cause chronic cerebro-spinal venous insufficiency (CCSVI) and may be involved in the development or exacerbation of multiple sclerosis.

Traditional risk factor assessment does not capture the extent of cardiovascular risk in systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is associated with accelerated atherosclerosis. However, the degree of endothelial dysfunction and its relationship to traditional and novel cardiovascular risk factors have not been examined in SLE.

METHODS

In a case-control design, 35 patients with clinically stable SLE and 35 control subjects matched for age, sex, body mass index and smoking status were studied. Arterial elasticity, lipid profile, homocysteine, measures of inflammation and oxidative stress were determined.

RESULTS

Among traditional vascular risk factors, there was a nonsignificant trend towards lower blood pressure in the control subjects, whereas low-density lipoprotein (LDL) cholesterol levels were significantly lower in the SLE group (2.5 vs 3.3 mmol/L, P < 0.001). Patients with SLE had significantly lower small artery elasticity (SAE; 4.9 vs 7.0 ml/mmHg x 100, P < 0.001) and higher plasma homocysteine (11.4 vs 8.3 mmol/L, P = 0.002) than control subjects. Levels of serum sVCAM-1 (614 vs 494 ng/mL, P = 0.002), oxidized LDL (144 vs 97, P < 0.001) and CD40 ligand (4385 vs 1373 pg/ml, P = 0.001) were significantly higher in SLE. Oxidized LDL levels, older age at SLE diagnosis and higher disease damage scores correlated inversely with SAE but not traditional risk factors.

CONCLUSION

Impaired endothelial function as shown by decreased SAE, and an adverse profile of novel proatherogenic and prothrombotic vascular disease risk factors were prevalent in clinically quiescent SLE. These findings show the vulnerability of patients with SLE for atherosclerosis, and emphasize that assessments based on traditional risk factors alone may be inadequate.

Geometric diffusions as a tool for harmonic analysis and structure definition of data: multiscale methods

In the companion article, a framework for structural multiscale geometric organization of subsets of R(n) and of graphs was introduced. Here, diffusion semigroups are used to generate multiscale analyses in order to organize and represent complex structures. We emphasize the multiscale nature of these problems and build scaling functions of Markov matrices (describing local transitions) that lead to macroscopic descriptions at different scales. The process of iterating or diffusing the Markov matrix is seen as a generalization of some aspects of the Newtonian paradigm, in which local infinitesimal transitions of a system lead to global macroscopic descriptions by integration. This article deals with the construction of fast-order N algorithms for data representation and for homogenization of heterogeneous structures.

Geometric diffusions as a tool for harmonic analysis and structure definition of data: diffusion maps

We provide a framework for structural multiscale geometric organization of graphs and subsets of R(n). We use diffusion semigroups to generate multiscale geometries in order to organize and represent complex structures. We show that appropriately selected eigenfunctions or scaling functions of Markov matrices, which describe local transitions, lead to macroscopic descriptions at different scales. The process of iterating or diffusing the Markov matrix is seen as a generalization of some aspects of the Newtonian paradigm, in which local infinitesimal transitions of a system lead to global macroscopic descriptions by integration. We provide a unified view of ideas from data analysis, machine learning, and numerical analysis.

Statistics of lateral geniculate nucleus (LGN) activity determine the segregation of ON/OFF subfields for simple cells in visual cortex

The receptive fields for simple cells in visual cortex show a strong preference for edges of a particular orientation and display adjacent excitatory and inhibitory subfields. These subfields are projections from ON-center and OFF-center lateral geniculate nucleus cells, respectively. Here we present a single-cell model using ON and OFF channels, a natural scene environment, and synaptic modification according to the Bienenstock, Cooper, and Munro (BCM) theory. Our results indicate that lateral geniculate nucleus cells must act predominantly in the linear region around the level of spontaneous activity, to lead to the observed segregation of ON/OFF subfields.

Spatio-temporal pattern for expression of galectin-3 in the murine utero-placental complex: evidence for differential regulation

In mice, immunoreactive galectin-3 protein has previously been localized in uterine epithelial cells adjacent to implanting blastocysts as well as in the decidualized endometrium of implantation sites, uterine natural killer cells, and several types of placental trophoblast cells. Because galectin-3 is a soluble extracellular molecule, protein localization by immunohistochemical methods does not demonstrate its cellular origin. Therefore, the present study was undertaken to determine precisely which cell types in the utero-placental complex express galectin-3 mRNA. In situ hybridization results demonstrated that galectin-3 mRNA was expressed throughout the utero-placental complex in all cell types previously shown to contain immunoreactive protein, including uterine epithelium, decidualized endometrium, uterine natural killer cells, and placental trophoblasts. These results indicate that galectin-3 protein is not synthesized in a restricted cell type and translocated through the extracellular spaces to other tissue compartments. Furthermore, Northern blot analysis of total RNA prepared from separated fetal and maternal components of utero-placental complexes demonstrated different patterns of expression for galectin-3 mRNA in the uterus and placenta. Relative levels of galectin-3 mRNA peak at midgestation in the implantation site and during the second half of gestation remain elevated in the placenta but decline in the uterus. Separate mechanisms for regulating expression of galectin-3 on opposite sides of the feto-maternal interface are indicated.

Cerebral trauma-induced changes in corpus striatal dopamine receptor subtypes

A device designed specifically for mild to severe concussions was used to produce quantitative experimental blunt brain injury in male Wistar rats. We have examined the effects of varying magnitudes of cerebral trauma on the maximal binding capacity (Bmax) of D1 and D2 dopamine (DA) receptors. The Bmax for each receptor subtype was obtained from Scatchard analyses of [3H]-SCH 23390 and [3H]Spiperone binding to striatal membrane. Anesthetized rats were injured--one, two, or three times--once every 24 h, with either a 68- or 268-g rubber-headed reflex hammer accelerated from a predetermined distance. Uninjured nonanesthetized (NA) and anesthetized (A) rats served as controls. No significant difference in receptor density was observed between NA and A rats for each receptor subtype. Immediately (0 h) following injury from the 68-g hammer weight, the density of D1 receptors decreased (50%), then increased (30%) above control levels by 24 h. The same pattern was observed with the 268-g hammer weight. Analysis of variance (ANOVA) showed that there was no overall effect of number of injuries or treatment on the density of D1 and D2 receptor subtypes. However, there was an interaction of both variables on the D1, but not D2, receptor subtype. Partial ANOVA for receptor densities after rats were injured either one, two, or three times showed that receptor density was altered only after the rats were injured one time. These results suggest that striatal DA D1 receptors are downregulated and then upregulated following isolated injury to the cerebral cortex.

Medunsa and the training of black doctors for South Africa

Medunsa, the Medical University of Southern Africa, was founded in 1976 to address both the under-representation of blacks in the health professions and the lack of good health care in the homelands. The university trains most of the black physicians, dentists, veterinarians, and allied health professionals in South Africa, and it places a great emphasis on community service and preventive medicine. Medunsa also has programs to help socially and academically disadvantaged applicants. In some respects, the ongoing development of Medunsa mirrors that of historically black health professions schools in the United States, and Medunsa struggles with some of the same problems. Medunsa can learn from the histories of these American schools as it faces the challenges of the post-apartheid era; in turn, all U.S. schools can learn from Medunsa's history as they struggle with physician supply questions and health care reform issues.

Potassium channel stimulation by natriuretic peptides through cGMP-dependent dephosphorylation

Natriuretic peptides inhibit the release and action of many hormones through cyclic guanosine monophosphate (cGMP), but the mechanism of cGMP action is unclear. In frog ventricular muscle and guinea-pig hippocampal neurons, cGMP inhibits voltage-activated Ca2+ currents by stimulating phosphodiesterase activity and reducing intracellular cyclic AMP; however, this mechanism is not involved in the action of cGMP on other channels or on Ca2+ channels in other cells. Natriuretic peptide receptors in the rat pituitary also stimulate guanylyl cyclase activity but inhibit secretion by increasing membrane conductance to potassium. In an electrophysiological study on rat pituitary tumour cells, we identified the large-conductance, calcium- and voltage-activated potassium channels (BK) as the primary target of another inhibitory neuropeptide, somatostatin. Here we report that atrial natriuretic peptide also stimulates BK channel activity in GH4C1 cells through protein dephosphorylation. Unlike somatostatin, however, the effect of atrial natriuretic peptide on BK channel activity is preceded by a rapid and potent stimulation of cGMP production and requires cGMP-dependent protein kinase activity. Protein phosphatase activation by cGMP-dependent kinase could explain the inhibitory effects of natriuretic peptides on electrical excitability and the antagonism of cGMP and cAMP in many systems.

Characterization of a biotinylated somatostatin analog as a receptor probe

The neuropeptide somatostatin (SRIF) triggers its biological effects by binding to high affinity membrane receptors. To develop a ligand useful for receptor affinity purification and localization, we have examined the ability of a novel monobiotinylated SRIF derivative to bind to receptors and streptavidin. Unlabeled [N-Biotinyl, Leu8, D-Trp22, Tyr25]SRIF28 (Bio-SRIF28) competed for [125I-Tyr11]SRIF binding to GH4C1 pituitary cell membranes with a Ki of 337 +/- 95 pM, comparable to that of native SRIF (193 +/- 16 pM). Studies using HPLC purified [125I]Bio-SRIF28 showed that equilibrium binding to membranes occurred within 120 min at 30 C and that the peptide-receptor complex dissociated slowly (t1/2 = 4.7 h). Analysis of saturation binding data gave an equilibrium dissociation constant for [125I]Bio-SRIF28 of 66 +/- 20 pM. Photoaffinity cross-linking of [125I]Bio-SRIF28 to membranes covalently labeled a broad 85 kDa band, as previously reported with the photolabile SRIF analog, [125I-Tyr11, Azidonitrobenzoyl-Lys4]SRIF. The binding of [125I]Bio-SRIF28 was potently inhibited by SRIF (Ki = 171 +/- 36 pM) and SRIF28 (299 +/- 102 pM) but not by structurally unrelated peptides. Furthermore, [125I]Bio-SRIF28 did not bind to membranes from GH(1)2C1 pituitary cells, which do not respond to SRIF and which lack [125I-Tyr11]SRIF binding sites. Finally, GppNHp and GTP gamma S both decreased [125I]Bio-SRIF28 binding whereas AppNHp did not. These studies showed that [125I]Bio-SRIF28 bound with high affinity to specific, G-protein coupled SRIF receptors. [125I]Bio-SRIF28 also bound with high affinity to streptavidin and this binding was very stable (t1/2 for dissociation = 19 h). Therefore, the affinity of the receptor for the Bio-SRIF28-streptavidin complex was determined by measuring the potency with which this preformed complex competed for [125I-Tyr11]SRIF binding. The Ki of the Bio-SRIF28-streptavidin complex (1110 +/- 47 pM) was only 3 times higher than that of uncomplexed Bio-SRIF28 (Ki = 337 +/- 95 pM). Dissociation of the [125I]Bio-SRIF28-streptavidin complex from receptors was slow (t1/2 = 3.9 h) but was increased over 200-fold by 1 microM GTP gamma S (t1/2 < 1 min). These data show that Bio-SRIF28 was able to bind simultaneously and with high affinity both to SRIF receptors and to streptavidin to form a stable ternary complex. Further, receptor binding of the Bio-SRIF28-streptavidin complex could be regulated by the addition of guanine nucleotides. Thus, Bio-SRIF28 should be useful for the affinity purification and in situ localization of SRIF receptors.

Evidence for a dual source of relaxin in the pregnant rat: immunolocalization in the corpora lutea and endometrium

Uterine tissue was collected from intact pregnant rats on days 4, 10-15, 18, and 22 of pregnancy and day 2 postpartum and from rats on day 22 of pregnancy after ovariectomy (day 9) and progesterone-estrogen treatment. Placental, cervical, mammary, and pituitary tissues were collected from intact pregnant rats on day 22. Ovarian tissue was collected from intact pregnant rats on days 15, 20, and 22. These tissues were evaluated for relaxin immunostaining at the light microscope level using an antiserum to purified rat relaxin and the avidin biotin immunostaining technique. Since the corpus luteum is the major source of relaxin in the rat, this tissue was used as a positive control. Relaxin immunostaining in the corpus luteum was observed in a discrete region of the cytoplasm. This pattern of staining corresponded with the discrete clustering of relaxin-containing secretory granules found in the rat luteal cells. Relaxin was not observed in the day 22 placenta, cervix, mammary gland, pituitary gland, or day 4-13 pregnant uterus. Relaxin immunostaining was detected in endometrial epithelial cells on days 14-22 of pregnancy and day 2 postpartum. Relaxin immunostaining was more evident at implantation sites than between implantation sites. Antimesometrial epithelial cells at implantation sites contained relaxin immunostaining. The mesometrial surface, which consists of the placenta and decidualized endometrium, did not contain relaxin immunostaining. Relaxin immunostaining was also present in the endometrial epithelial cells of the day 22 pregnant rats that had been ovariectomized on day 9 and given subsequent replacement therapy with ovarian steroids. The presence of relaxin immunostaining in the ovariectomized rat indicates the endometrium is not sequestering relaxin secreted from the corpus luteum. These data provide evidence that the pregnant rat endometrium is a source of relaxin in addition to the corpus luteum. The appearance of relaxin in endometrial epithelial cells after implantation and its prominence at implantation sites may indicate that locally secreted conceptus factors stimulate endometrial relaxin synthesis.

Monoclonal antibodies specific for rat relaxin. VI. Passive immunization with monoclonal antibodies throughout the second half of pregnancy disrupts histological changes associated with cervical softening at parturition in rats

Relaxin, which is secreted by the corpora lutea throughout the second half of rat pregnancy, promotes the growth and softening of the cervix. The mechanisms at both the cellular and molecular levels by which relaxin brings about these effects remain to be determined. The present study examined the influence of endogenous relaxin on the histological changes associated with cervical softening. A monoclonal antibody for rat relaxin, designated MCA1, was injected iv daily on days 12-22 of gestation. Cervices were removed on day 22, fixed in 10% buffered formalin, embedded in paraffin, and processed for histological staining. Tissue sections (5 microns thick) were stained with Gomori's trichrome stain (collagen), Orcein stain (elastin), or periodic acid-Schiff (polysaccharide). Qualitative and quantitative analyses identified several histological parameters in MCA1-treated rats that differed markedly from those in control rats. Cervices obtained from MCA1-treated rats contained collagen fiber bundles with greater compactness; elastin fibers with greater density, length and interdigitation; arteries with smaller cross-sectional areas; and luminal involutions with smaller areas than controls. The cervices of MCA1-treated rats appeared to contain fewer vacuolated epithelial cells, which secrete polysaccharide-rich material, than did cervices obtained from controls. It seems plausible that most, if not all, of these relaxin-induced modifications of the histological characteristics of the cervix facilitate birth.

Monoclonal antibodies specific for rat relaxin. V. Passive immunization with monoclonal antibodies throughout the second half of pregnancy disrupts development of the mammary apparatus and, hence, lactational performance in rats

There were two related objectives to this study. The first was to determine the influence of relaxin on development of the mammary apparatus (nipples and glands) during the second half of pregnancy. The second was to determine whether the relaxin-dependent development of the mammary apparatus was required for normal postpartum lactational performance. Both objectives were accomplished by neutralizing endogenous relaxin throughout the second half of pregnancy with a monoclonal antibody specific for rat relaxin (MCA1). MCA1 was administered iv to rats daily from days 12-22 of pregnancy. On day 22 the morphology of the mammary apparatus of MCA1-treated rats differed from that of controls; nipples were dramatically smaller, collagen fibers had significantly greater mean density and consistency, and elastin fibers had greater mean density, length, and interdigitation. In addition, the mean number of alveoli surrounding lactiferous ducts was significantly smaller in MCA1-treated rats than in controls. There were no differences between MCA1-treated rats and controls in the mean thickness of connective tissue surrounding ducts, the height or density of luminal cells lining lactiferous ducts, or the sizes of either adipocytes or arteries. To examine lactational performance, MCA1-treated and control rats were cesarean sectioned between 2100-2400 h on day 22 of pregnancy and given foster pups born of untreated intact donors. Although both MCA1-treated rats and control rats exhibited a high incidence of maternal behavior after cesarean delivery, mean pup weight and incidence of live pups declined markedly during days 1-5 of fosterage in MCA1-treated rats compared to controls. Furthermore, unlike controls, there was no observable postpartum nipple development in MCA1-treated rats by day 5 of fosterage. Mammary glands obtained from MCA1-treated rats on day 5 of fosterage had markedly lower mean weight than controls. This study demonstrates that passive immunization of endogenous relaxin throughout the second half of pregnancy disrupts development of the nipples and mammary glands in the rat. Moreover, it establishes that relaxin's effects on the development of the mammary apparatus during pregnancy are essential for growth and survival of the young during lactation.

Identification of somatostatin receptors by covalent labeling with a novel photoreactive somatostatin analog

We have synthesized two photoreactive derivatives of somatostatin, namely [125I-Tyr11,azidonitrobenzoyl (ANB)-Lys4]somatostatin and [125I-Tyr11,ANB-Lys9]somatostatin, and used them to characterize somatostatin receptors biochemically in several cell types. Saturation binding experiments carried out in the dark demonstrated that [125I-Tyr11,ANB-Lys4]somatostatin bound with high affinity (KD = 126 +/- 39 pM) to a single class of binding sites in GH4C1 pituitary cell membranes. The affinity of this analog was similar to that of the unsubstituted peptide [125I-Tyr11]somatostatin (207 +/- 3 pM). In contrast, specific binding was not observed with [125I-Tyr11,ANB-Lys9]somatostatin. The binding of both [125I-Tyr11,ANB-Lys4]somatostatin and [125I-Tyr11]somatostatin was potently inhibited by somatostatin (EC50 = 300 pM) whereas at 100 nM unrelated peptides had no effect. Furthermore, both pertussis toxin treatment and guanyl-5'yl imidophosphate (Gpp(NH)p) markedly reduced [125I-Tyr11,ANB-Lys4]somatostatin binding. Thus, [125I-Tyr11,ANB-Lys4]somatostatin binds to G-protein coupled somatostatin receptors with high affinity. To characterize these receptors biochemically, GH4C1 cell membranes were irradiated with ultraviolet light following the binding incubation, and the labeled proteins were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. A major band of 85 kDa was specifically labeled with [125I-Tyr11,ANB-Lys4]somatostatin but not with [125I-Tyr11,ANB-Lys9]somatostatin or [125I-Tyr11]somatostatin. The binding affinity of the 85-kDa protein for [125I-Tyr11,ANB-Lys4]somatostatin was very high (Kd = 34 pM). Labeling of this protein was inhibited competitively by somatostatin (EC50 = 140 +/- 80 pM) but not by unrelated peptides. Furthermore, this band was not labeled in pertussis toxin-treated membranes or in untreated membranes incubated with Gpp(NH)p. Finally, [125I-Tyr11,ANB-Lys4]somatostatin specifically labeled bands of 82, 75, and 72 kDa in membranes prepared from mouse pituitary AtT-20 cells, rat pancreatic acinar AR4-2J cells, and HIT hamster islet cells, respectively. Thus, [125I-Tyr11,ANB-Lys4]somatostatin represents the first photolabile somatostatin analog able to bind to receptors with high affinity. Our studies demonstrate that this novel peptide covalently labels specific somatostatin receptors in a variety of target cell types.

Improved cardiovascular hemodynamics with atrioventricular sequential pacing compared with ventricular demand pacing

To determine the advantages of atrioventricular (AV) sequential pacing over ventricular demand pacing, paired cardiovascular hemodynamic studies were performed in each pacing mode at a constant heart rate. The paired studies included determination of ejection fraction (EF) by echocardiography and gated blood pool radionuclide scanning, and of cardiac output (CO) by the indicator-dilution method. There was no significant difference in EF with either pacing mode. Determined by echocardiography, EF with AV sequential pacing was 57% compared with 56% with ventricular demand pacing; by the gated blood pool method, EF with AV sequential pacing was 58% compared with 57% in the ventricular mode. Significant improvement with AV sequential pacing was seen in CO (4.75 L/min from 3.75 L/min; p less than 0.01); stroke volume (58 ml from 48 ml; p less than 0.02); arteriovenous oxygen content difference (4.9 vol% from 5.6 vol%; p less than 0.01); total peripheral resistance (1,724 dynes sec cm-5 from 2,025 dynes sec cm-5; p less than 0.01); and cardiac contractility, as reflected by mixing time (6.9 seconds from 8.0 seconds; p less than 0.02). No significant changes were noted in mean arterial or atrial pressure or in systemic oxygen consumption. In a second group of 6 patients, similar paired studies were done in AV sequential pacing modes before and after therapeutic reduction of total peripheral resistance. A significant increase in CO (43%) was observed following reduction in total peripheral resistance. We conclude that AV sequential pacing improves CO more effectively than ventricular demand pacing. Cardiac output can be further enhanced in patients with congestive heart failure by pretreatment with agents to reduce total peripheral resistance.

Reflex constriction of significant coronary stenosis as a mechanism contributing to ischemic left ventricular dysfunction during isometric exercise

To study the mechanisms of myocardial ischemia during isometric exercise, handgrip was sustained, for 4.5 min at 25% of maximum by 11 patients with at least one significant coronary stenosis each, during cardiac catheterization. After recovery, the handgrip that was repeated with simultaneous infusion of nitroglycerin (50 micrograms over 4 min) directly into the diseased vessel. The cardiovascular response was assessed by hemodynamic and by computer-assisted measurements of stenosis. During the first handgrip test pulmonary capillary wedge pressure rose 56% (15 to 23 mm Hg; p less than .001), the heart rate-systolic pressure product rose 33% (p less than .01), and the diseased epicardial arteries constricted. Luminal area in the stenotic segment was reduced by 35% (p less than .01), resulting in a 243% increase in estimated stenotic flow resistance (30 to 103 mm Hg/ml/sec; p less than .001). During handgrip with intracoronary nitroglycerin, the pressure-rate product again increased 33%, but relative to resting control, capillary wedge pressure fell 4 mm Hg in association with a 32% increase in luminal area of the stenosis and a 28% reduction in flow resistance (all significantly different from the response to handgrip alone: p less than .001, .01, and .005, respectively). Thus, coronary vasoconstriction, not increased pressure-rate product, is the dominant mechanism for ischemic left ventricular dysfunction during isometric exercise in patients with significant coronary stenoses.

Influence of length of aortic occlusion with cold potassium cardioplegia on early and late mortality in cardiac valve replacement

This study determines if prolonged aortic crossclamp time (ACC) with the use of cold potassium cardioplegia during elective cardiac valve replacement contributed to the risk of operative mortality in 225 patients. In Group I (143 patients), the ACC was less than 120 minutes (mean 86) and in Group II (82 patients), it was greater than 120 minutes (mean 146). The preoperative variables showed that Group II contained more severely ill patients who were undergoing more complex operations than in Group I. The operative mortality rate was 7% in Group I and 10% in Group II (p = not significant). Postoperative inotropic support was required in 13% of Group I and 30% of Group II patients (p less than 0.005). Operative mortality in patients in New York Heart Association (NYHA) functional class I and II was 0 and in patients in classes III and IV it was 13% (p less than 0.00008). Five percent of patients in NYHA classes I and II and 32% in classes III and IV required inotropic support (p less than 0.000005). The actuarial survival at 60 months was 88 +/- 3% for Group I and 77 +/- 7% for Group II (NS). For the NYHA class I and II patients, however, it was significantly better (98 +/- 2%) than class III and IV patients (75 +/- 5%) (p less than 0.0001). Analysis by logistic equation revealed that the NYHA functional classes III and IV were significant incremental risk factors for probability of in-hospital mortality (p less than 0.0001) but not the ACC time (p greater than 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)

The clinical and laboratory correlates of nasal polyps in cystic fibrosis

The clinical histories, chest X-ray appearances, skin prick test results, pulmonary function and IgE levels of 20 patients with cystic fibrosis (C.F.) complicated by nasal polyps have been compared with those of 97 C.F. controls. The patients who had developed polyps had a different clustering of symptoms to the controls with heavier birthweights, later presentations, milder gastrointestinal symptoms in infancy, less infection with Staphylococcus aureus and better vital capacities. There was no evidence on history, skin testing or IgE levels that the polyps patients were more allergic. It is likely, therefore, that nasal polyps in C.F. are due to a primary effect of the C.F. gene, although they could also be the effect of chronic nasal infection.

Long-term survival after coronary bypass surgery. Comparison of various subsets of patients with general population

Life-table analysis consecutive cases of isolated coronary bypass surgery at the Buffalo Hospital between 1973 and 1977 showed an estimated survival of 94 per cent at five years, equal to that of an age- and sex-matched group of the US population. Subsets of these patients divided according to sex, age, number of vessels narrowed, number of segments grafted, history of myocardial infarction, ejection fraction, and presence of unstable angina have estimated survivals not statistically less in any of these subsets than that of matched cohorts of the general population.

Hormonal bioassay of gonadotropin-producing hepatoblastoma

Hepatoblastoma was associated with signs of isosexual precocity in an 11-month-old boy. Circulating gonadotropic hormone levels were elevated. Gonadotropic activity was demonstrated by bioassay in extracts of primary and metastatic tumor, and in media surrounding long-term tissue culture of the primary tumor. Morphology of the endocrine glands and bioassay of the pituitary gland obtained at autopsy indicated the presence of gonadotropins and other tropic hormones despite the physiologically abnormal hormone status. These ae the first direct studies of pituitary hormone content in this syndrome.

Cold blood--potassium cardioplegia

A technique is described for providing myocardial protection utilizing oxygenated blood that is drawn from the pump oxygenator and passed through two disposable cardioplegic cooling coils, which are joined in series and submerged in ice slush. A potassium-containing cardioplegic solution is run into the oxygenated blood at the level of the cooling coils. The amount of blood used in the blood-potassium cardioplegic mixture is controlled using a screw clamp. This method has been used with excellent results in 150 consecutive patients undergoing aortocoronary saphenous vein bypass grafting.

Refinements in coronary artery surgery contributing to improved survival

Reviews of the literature and controlled studies of medical versus surgical treatment of coronary artery disease that include surgical results from 3 or 4 years ago may not be pertinent to therapeutic decisions made today. The results in our patients operated during 2 two-year periods (1974--1976, Group I and 1976--1978, Group II) are compared. The Group II patients had more severe coronary artery disease. They had significantly more grafts per patient (p less than .001), their cardiopulmonary bypass time was significantly reduced (p less than .001), they received less inotropic support (p less than .005) and spent less time in the intensive care unit (p less than .001). There was a significant decrease in the overall perioperative mortality (30-day) in the patients of Group II (p less than .055). The second two-year period coincided with the adoption of refinements in the intraoperative preservation of myocardium and also in surgical technique. These refinements are discussed in detail.

Left ventricular laceration due to stented prosthesis

Complications following open chest massage in patients with porcine xenografts in the mitral location have not been previously described. The authors report a case of cardiac resuscitation following mitral valve replacement with a stented porcine valve. The patient died following brief closed chest, and then, prolonged open chest, cardiac massage. Autopsy showed laceration of the left ventricle by the prosthetic valve stents. Physicians involved in the postoperative care of patients with stented prosthetic valves should be aware of this complication and should exercise caution when applying manual compression in the region of the posterolateral base of the heart.

The revival of the horseshoe graft (side-to-side saphenous-vein-to-aorta anastomosis)

The technique of the horseshoe graft, side-to-side saphenous-vein-to-aorta anastomosis, using a long saphenous vein harvested from the leg is described in this communication. The lack of valves between the ankle and the knee and the high caliber natural Y distributions make this technique attractive. Constructing a double set of vein graft provides, in particular, unlimited possibilities for the construction of six to eight grafts if this appears anatomically feasible.

Decompression of the heart with siphon drainage

A simple technique for inducing intracavitary hypothermic cardioplegia and decompressing the left heart through the ascending aorta is presented. The technique is based on siphon drainage, which eliminates the dangers of air embolism.

Detection of creatine kinase BB isoenzyme in sera of patients undergoing aortocoronary bypass surgery

Creatine kinase BB isoenzyme (CK-BB) was detected intraoperatively in 22 of 25 patients undergoing aortocoronary bypass surgery, both in the coronary sinus and in the mixed venous blood. In a group of 10 patients in whom selective intracavitary profound hypothermic arrest was used, CK-BB values were lower than in another group of 10 patients, in whom controlled ventricular fibrillation with moderate total body hypothermia was instituted. This latter group also had higher levels of CK-MB. Patients who developed acute myocardial infarction immediately prior to or during the surgical intervention had the highest CK-BB values. This enzyme appeared as early as 15 minutes after the institution of cardiopulmonary bypass and disappeared within 6 hours. It is considered that part of the BB isoenzyme in serum of patients undergoing heart surgery is of myocardial origin.

Selective intracavitary and coronary profound hypothermic cardioplegia for myocardial preservation: a new technique

A technique is described for selective intracavitary and coronary hypothermic perfusion during cardiac bypass with cardioplegia to facilitate cardiac operations. A cold perfusate (Plasmalyte 148 and mannitol, 12.5 gm/L at 8 degrees to 10 degrees C) is administered with the aid of a low-flow perfusion pump into the left ventricular cavity and coronary circulation through an apical perfusion-venting (Per-Vent) catheter. This perfusate cools the myocardium rapidly and homogeneously to a temperature of 15 degrees to 20 degrees C. Within this temperature range, complete cardioplegia occurs and the safe ischemia period can be extended to 120 minutes. This method was applied in 50 unselected consecutive adult patients undergoing aortocoronary saphenous vein bypass grafting or aortic or mitral valve replacement. All patients survived and had excellent recovery of ventricular function.

Early and long-term effects on direct myocardial revascularization on cardiac function: a prospective study using multivariable physiological analysis

Perioperative and late follow-up hemodynamic cardiovascular studies to assess the effects of direct myocardial revascularization on cardiac function objectively have been completed on 51 patients. Analysis of the data delineated three distinct groups basedon the patterns of their early postoperative recovery. Group I patients (12) had a hyperdynamic cardiovascular response to operation and returned to a normal physiological range of cardiac function within 24 hours. Group II patients (24) initially had moderate to severe myocardial decompensation postoperatively but responded to inotropic support and moved into the normal physiological range within 24 to 48 hours. Group III patients (15) had severe, prolonged myocardial decompensation with little response to inotropic support. There were no early deaths in Group I, 1 early iatrogenic death in Group II, and 2 deaths from sepsis, 1 in Group I and 1 in Group II. All 7 cardiogenic deaths occurred in Group III patients. Late follow-up studies 4 to 23 months postoperatively have been completed on 29 patients. These showed cardiovascular stability in the mean values in Groups I and II. Significant improvement in mean cardiac function was seen in surviving Group III patients.

Total excision of the sternum and thoracic pedicle transposition of the greater omentum; useful strategems in managing severe mediastinal infection following open heart surgery

Mediastinal sepsis following open heart surgery is a significant cause of death. Open drainage of the mediastinumalone was employed originally in management of this problem. More recently, debridement, drainage, and reclosure have been used. Various irrigation solutions, such as antibiotics and Betadine, have been advocated to control severe mediastinal sepsis. Three principles of management in patients unresponsiveness to the above techniques have proved successful in two patients with life-threatening mediastinal sepsis: (1) radical, complete excision of the sternum and adjacent costal cartilages; (2) transposition of the greater omentum on a vascular pedicle to the mediastinum; and (3) primary closure with full-thickness rotational skin flaps. The radical excision of the sternum removes residual foci of sepsis in cartilage and sternal bone marrow. The transposition of the omentum provides a highly vascular, rapidly granulating covering for the contaminated great vessels and hase been successfully to prevent recurrence of suture line bleeding of an exposed ascending aortic anastomosis site. Primary closure of the wound with full-thickness skin flaps provides a suprisingly satisfactory covering for the heart. Preoperative and postoperative measurements of ventilatory mechanics have shown relatively small ventilatory impairment after the alteration of the thoracic cage imposed by excision of the sternum. Two patients have returned to active lives. A treatment failure probably due to incomplete adherence to these guidelines also is presented.

Free internal mammary artery for coronary bypass

An improved technique of free internal mammary artery (IMA) to ascending aorta anastomosis for coronary bypass is described. A small patch vein with a suitable side branch or branches is interposed, connecting the proximal end of a detached IMA to the ascending aorta. A single or double free IMA alone or in combination with an additional saphenous vein graft was performed in 77 patients. A total of 125 free IMA grafts were done. The hospital mortality was 2-7% and late mortality 1-4%. Seventy-one of the 74 surviving patients had no angina and returned to a normal life. Postoperative coronary arteriography in 65 patients showed a patency rate of 96%. On year's experience with this technique is very encouraging. However, prolonged follow-up is necessary to determine if free IMA, as used by us, will increase the long-term patency rate.

Optical modal evolution 3-dB coupler

A planar optical 3-dB coupler is proposed that uses only a single region of mode conversion followed by a region of adiabatic modal evolution. These two regions are provided by an overlay with fast and slow tapers, which makes the device synchronous at a single point. Device length is noncritical. The device was fabricated with sputtered barium silicate and fused silica films and tested experimentally. Maximum power transfer of 40% was limited by a fabrication problem with the fast taper, but agreement with theory was obtained. An approximate coupled mode representation of the coupling between local normal modes is used to estimate power transfer at an abrupt transition and to provide design requirements for the fast and slow tapers. The theoretical concepts developed are applied to describe the operation of conventional directional 3-dB couplers and channel modal evolution 3-dB couplers which use branching waveguides.

Optical access couplers and a comparison of multiterminal fiber communication systems

Optical T and multiple T access couplers designed for tapped trunk line multiterminal communication systems that use bundles of multimode fibers as the transmission media have been investigated. The particular coupler designs tested used bent Pyrex rods for bifurcation and scrambling. Coupler throughput losses (not counting packing fraction losses) are 1.5-2.5 dB. The bent rod optical T and multiple T access couplers must be used with high N.A., low packing fraction loss fibers. To avoid the use of a repeater a multiple T or star configuration must be used in a system comprising ten or more terminals.

Free internal mammary artery graft. An improved surgical technique

An improved method of free internal mammary artery (IMA)-to-ascending aorta anastomosis for cornoary bypass is described. We interposed a small patch of vein with a suitable side-branch or brancyes in connecting the proximal end of a detached IMA or radial artery. Thirty-four free IMA-to-coronary artery bypasses were performed in 25 patients; 16 right IMA, 14 left IMA, and 4 radial arteries were used. Cornoary angiographic follow-up studies performed in all patients between two weeks and six months after operation proved that all grafts were patent and showing a larger lumen than is usually seen in undetached IMA grafts. Concomitantly marked relief of anginal pain was noted in all patients. Oour experience with this technique is very encouraging. All patients are being followed to evaluate long-term graft patency.