Coronary artery bypass grafting: the Society of Thoracic Surgeons National Database experience

The need for accurate risk assessment has become an indispensable element in the practice of cardiac surgery. The Society of Thoracic Surgeons National Cardiac Surgery Database allows subscribing institutions to perform sophisticated patient risk assessment using traditional statistical tools and a newly developed risk model of operative mortality. The database experience with isolated coronary artery bypass grafting has been studied most closely at this point and serves as the basis for this report. The approach to operative risk assessment is presented along with an analysis of important risk factors in the practice of coronary artery surgery from 1980 through 1990. The database contains records of 80,881 patients undergoing coronary artery bypass grafting in numerous institutions from 1980 through 1990. These records were used to conduct a detailed analysis of risk factors associated with coronary operations in this time interval and to present statistical methods used to formulate a risk equation that allows one to predict the probability of operative death. In the course of this decade, there were clearly defined trends showing a statistically significant increase in adverse patient risk factors. The risk model has proven to be a reliable tool for predicting the probability of operative death in an individual patient and may be valuable in both patient counseling and medical decision making. Large multi-institutional databases of this type are key ingredients of modern operative risk assessment. A database containing a broad national experience of this type can represent an aggregate experience that may well approximate a universally accepted standard of care.

Evidence for the existence of low-energy laser bioeffects on the nervous system

The reported effects of low-energy laser irradiation on the nervous system are manifested in alterations in cellular and extracellular biochemical constituents and reactions, as well as in changes in cell division rates. These bioeffects were observed in both in vivo and in vitro experiments. Other observed phenomena relate to the function of the nervous system and consist mainly of induced alteration in electrical conduction, stimulation thresholds, and behavioral effects. Clinical aspects of low-energy laser bioeffects relate mainly to pain mitigation and postponement of the posttraumatic neural degeneration processes. Many of the reported observations were obtained by experiments apparently conducted according to less than rigorous scientific criteria, and some could not be duplicated. On the whole, however, there is little doubt that low-energy laser irradiation exerts some effects on the nervous system under specific conditions of irradiation and tissue exposure via a mechanism which is probably photochemical in nature.

Impact of internal mammary artery conduits on operative mortality in coronary revascularization

The long-term advantages of internal mammary artery (IMA) conduits in coronary artery bypass graft (CABG) procedures are widely recognized, but the immediate short-term impact of IMA grafts is not well defined. The purpose of this study was to investigate the influence of IMA conduits on CABG operative mortality (OM). A retrospective study of two groups of patients undergoing isolated CABG was performed. Patients having at least one IMA graft (group 1) were compared with those with only venous conduits (group 2). The patient population was taken from The Society of Thoracic Surgeons National Cardiac Surgery Database, which contains a broad multi-institutional experience. A total of 38,578 registered patients undergoing isolated CABG from 1987 through 1991 were studied. Of these, 18,614 patients had at least one IMA conduit (group 1), whereas 19,964 had CABG using entirely venous conduits (group 2). The OM for group 1 was 2.0% (365/18,614), whereas the mortality was 4.5% (903/19,964) for group 2 (p < 0.005). Patient subgroups were examined to determine if the improved OM associated with IMA grafting was present in these patient subsets. The population was broken down according to age, sex, ejection fraction, extent of coronary disease, and operative priority. For each subset, univariate analysis showed that group 1 OM was significantly less (p < 0.005) than the OM for group 2. Numerous combinations of these patient parameters were also analyzed. Group 1 patients had a significant (p < 0.05) improvement in OM in each combination except for patients more than 70 years of age requiring reoperations.(ABSTRACT TRUNCATED AT 250 WORDS)

Case report: fatal lymphoproliferative disease seven weeks after liver transplantation

A 42-year-old man developed a lymphoproliferative disorder and died seven weeks after undergoing liver transplantation for primary biliary cirrhosis. At autopsy, diffuse large cell lymphoma was noted to involve almost every organ. Molecular analyses of DNA isolated from an enlarged periportal lymph node indicated the presence of Epstein-Barr virus sequences and several JH immunoglobulin gene rearrangements (consistent with the presence of more than one greatly expanded clone of lymphoid cells of B-cell lineage). This case underscores the possibility of the rapid emergence of lymphoproliferative disorder related to Epstein-Barr virus early after liver transplantation, masked by a concurrent episode of acute rejection.

Astrocytes play a major role in the control of neuronal proliferation in vitro

The elements that control neuronal proliferation are largely unknown. Proliferating neurons in cultures of goldfish brain were studied in an attempt to identify the cell types involved. Neuronal proliferation was found to occur only when the neuronal stem cells were in direct contact with astrocytes, and never directly on the substrate. The regulation of neuronal proliferation thus appears to be mediated, at least in part, by contact with astrocytes. In addition, neurite extension was inhibited by medium conditioned by fish astrocytes. Since neurite extension and neuronal proliferation are mutually exclusive processes, inhibition of neurite extension by soluble substances derived from the astrocytes is probably one of the mechanisms controlling neuronal proliferation. The complex reciprocal relationship between neurons and astrocytes is also demonstrated by an observed inhibition of astrocytic proliferation by medium conditioned by differentiating fish neurons. This inhibition of astrocytic proliferation might be part of a mechanism through which interference with neuronal differentiation by astrocytes is avoided. The results of this study thus suggest that astrocytes, in addition to their known roles in controlling neuronal migration, neuronal differentiation and neurite elongation, may also play a role in the control of neuronal proliferation.

FK506 versus cyclosporine as primary immunosuppressive agent for orthotopic liver allograft recipients. Histologic and immunopathologic observations

We investigated possible explanations for the common occurrence of perivenular lesions in liver allografts of patients on FK506 within a few weeks to several months after OLT. Hematoxylin and eosin-stained sections of pre- and postperfusion biopsy specimens and day 7 post-transplant protocol biopsy specimens from 31 patients, randomly assigned to either FK506 or CsA as primary immunosuppressive agent, were reviewed, and immunohistochemical stains for HLA-DR antigen and S-100 protein were performed by the avidin-biotin peroxidase complex method. The histologic features of cellular rejection in the portal tracts of day 7 posttransplant allograft biopsy specimens from patients on FK506 were milder than those from patients on CsA. Immunohistochemical stains for HLA-DR showed intense positivity in a variety of cell types in day 7 posttransplant specimens from both groups, including sinusoidal-lining cells, bile duct epithelial cells, vascular endothelial cells, inflammatory cells, and occasional injured hepatocytes. Although diffuse lobular staining was seen in the majority of cases in both groups, either with or without rejection, liver biopsy specimens from patients on FK506 showed concentration of positively stained cells in perivenular regions more often, and at a lower overall histologic grade of rejection, than specimens from patients on CsA. There were no differences in the number and distribution of S-100 protein-positive dendritic APC between biopsy specimens from FK506 versus CsA-treated patients, or between specimens with and without cellular rejection in either group. It is suggested that the development of perivenular injury, which is seen frequently in allograft biopsy specimens from patients on FK506 obtained at various intervals after transplantation, may be related to drug toxicity rather than to the process of allograft rejection.

A new method for expressing axonal size: rat optic nerve analysis

Analysis of the shape of the cross sections of adult rat optic nerve axons reveals that the majority of axons do not have a true circular shape. Therefore, determination of axonal size has to utilize methods of approximation. The method presented here utilizes three calculated parameters for expression of axonal size: (i) axonal diameter, as calculated from its area, or (ii) axonal diameter, as calculated from its perimeter, both assuming axonal shape to be a perfect circle and (iii) axonal shape factor, which represents the divergence of the axon from a perfect circular shape. The use of the calculated axonal diameter, with a correction for its shape factor, provides a normalized way of expressing axonal size.

Adherence and psychological adjustment among women at high risk for breast cancer

Increasingly, women with a positive family history of breast cancer are being targeted for cancer prevention and control efforts. Two findings have been demonstrated consistently across studies of this high risk population. First, these women often have high levels of psychological distress, as well as persistent and intrusive worries about developing breast cancer. Second, despite their increased risk for developing breast cancer, a substantial proportion of these women do not adhere to recommended breast cancer screening guidelines. There is growing evidence that psychological distress is an important barrier to adherence among high risk women. Despite this, little is known about how to intervene to improve psychological adjustment and adherence in this population. In the present paper, we review the literature on adherence and psychological adjustment in women who are at increased risk for breast cancer because of a positive family history of disease. This review provides the basis for a discussion of potential intervention strategies designed to increase adherence and reduce psychological distress in this population. Finally, we present some of the psychological implications of recent developments in genetic testing for breast cancer susceptibility.

Genetic heterogeneity among blue-cone monochromats

Thirty-three unrelated subjects with blue-cone monochromacy or closely related variants of blue-cone monochromacy were examined for rearrangements in the tandem array of genes encoding the red- and green-cone pigments. In 24 subjects, eight genotypes were found that would be predicted to eliminate the function of all of the genes within the array. As observed in an earlier study, the rearrangements involve either deletion of a locus control region adjacent to the gene array or loss of function via homologous recombination and point mutation. One inactivating mutation, Cys203-to-Arg, was found in 15 probands who carry single genes and in both visual pigment genes in one subject whose array has two genes. This mutation was also found in at least one of the visual pigment genes in 1 subject whose array has multiple genes and in 2 of 321 control subjects, suggesting that preexisting Cys203-to-Arg mutations constitute a reservoir of chromosomes that are predisposed to generate blue-cone-monochromat genotypes by unequal homologous recombination and/or gene conversion. Two other point mutations were identified: (a) Arg247-to-Ter in one subject with a single red-pigment gene and (b) Pro307-to-Leu in one subject with a single 5' red-3' green hybrid gene. The observed heterogeneity of genotypes points to the existence of multiple one- and two-step mutational pathways to blue-cone monochromacy.

Splice site mutation in the human protein C gene associated with venous thrombosis: demonstration of exon skipping by ectopic transcript analysis

Heterozygosity for a G-->C mutation converting the highly conserved Gln184 (CAG) to His (CAC) was identified at the last nucleotide of exon 7 of the protein C gene in two family members with deep vein thrombosis. As the nucleotide is a part of the 5 splice site of intron G, it was examined how the mutation affected splicing of protein C pre-mRNA. Relevant protein C cDNA fragments were amplified with polymerase chain reaction after reverse transcription of ectopic mRNA from peripheral blood lymphocytes. Southern blot analysis and nucleotide sequencing of these fragments showed a fragment (A) corresponding to correctly spliced mRNA originating from the normal allele and a fragment (B) corresponding to a truncated mRNA lacking exon 7, originating from the mutant allele. A third fragment (C) lacking exons 7 and 8 was identified in both affected and unaffected family members, as well as in normal controls. Analysis of human liver protein C mRNA indicated that the ectopic lymphocyte mRNA was qualitatively representative for the tissue-specific mRNA. In conclusion, evidence is provided showing that the mutation abolishes formation of correctly spliced mRNA. This agrees with the observation that the mutation results in a type 1 protein C deficiency.

Linkage of Wiskott-Aldrich syndrome with three marker loci, DXS426, SYP and TFE3, which map to the Xp11.3-p11.22 region

Linkage analysis was performed in 19 families segregating for the Wiskott-Aldrich syndrome (WAS) and in 1 family with X-linked thrombocytopenia using nine polymorphic DNA markers spanning the interval DXS7-DXS14. The results confirm close linkage of WAS to the DXS7, TIMP, OATL1, DXS255, DXS146, and DXS14 loci and reveal three additional marker loci, DXS426, SYP, and TFE3, to be closely linked to WAS. The linkage data are also consistent with the localization of X-linked thrombocytopenia to the same chromosomal region as WAS and support localization of the WAS gene between the TIMP and DXS146 loci. However, the data were insufficient for positioning these disease genes with respect to the four marker loci that map within this latter interval. Analysis of recombination events between the marker loci place the TFE3 gene distal to DXS255 and favor the marker loci order Xpter-DXS7-(DXS426, TIMP)-(OATL1, SYP, TFE3)-DXS255-DXS146-DXS14.

Familial Pallister-Hall syndrome: case report and hormonal evaluation

Pallister-Hall syndrome is a usually lethal dysplasia/malformation syndrome characterized by hypothalamic hamartoblastoma, hypopituitarism, postaxial polydactyly, craniofacial malformations, imperforate anus, and other malformations. We report a familial case in a male infant and his female sib fetus, suggesting autosomal recessive inheritance, or germinal mosaicism for an autosomal dominant mutation, or a segregating submicroscopic chromosome abnormality. Detailed endocrine evaluation on the surviving infant revealed documented pituitary function, pituitary deficit, and hypothalamic deficiency. We suggest that hypothalamic dysfunction contributes to the hypopituitarism seen in Pallister-Hall syndrome.

Cloning and characteristics of fish glial fibrillary acidic protein: implications for optic nerve regeneration

Mammalian central nervous system neurons do not regenerate after axonal injury, unlike their counterparts in fish and amphibians. After axonal injury, glial cells in mammals do not support regrowth of axons, while in fish they support the regeneration process. Controversy exists as to whether or not the intact fish optic nerve expresses glial fibrillary acidic protein, a well-known marker for mature astrocytes, and thus whether its astrocytes differ in this respect from those of the brain and spinal cord, as well as from optic nerve astrocytes of other species. In an attempt to resolve this question we cloned fish glial fibrillary acidic protein. Two different complementary DNA clones were isolated from a carp brain complementary DNA library, each encoding a different form of glial fibrillary acidic protein apparently originating from different genes. Monospecific polyclonal antibodies were raised against a peptide synthesized according to the predicted amino acid sequence, and used to identify and localize the fish glial fibrillary acidic protein. Two glial fibrillary acidic proteins (of 49 kDa and 51 kDa) were identified by the antibodies in all tested fish central nervous system tissues. The antibodies were then used to examine glial fibrillary acidic protein immunoreactivity in sections taken from uninjured and injured optic nerves of goldfish. Injury was followed by an elevation in glial fibrillary acidic protein immunoreactivity along the whole length of the nerve, except at the site of the injury, where--as in the case of vimentin--no immunoreactivity was detectable. However, in contrast to vimentin-positive glial cells, which repopulate the site of the injury soon after the optic nerve is injured, glial fibrillary acidic protein-positive glial cells remained outside the injury site for as long as 6 weeks after the injury. Despite the injury-induced changes in glial fibrillary acidic protein immunoreactivity, no change was observed in the level of transcript encoding glial fibrillary acidic protein after injury, while there was an increase in the amount of glial fibrillary acidic protein associated with the cytoskeleton and a reduction in the soluble form. These results suggest that the injury-induced changes in immunoreactivity on sections involve changes not in transcription or translation of glial fibrillary acidic protein, but in glial fibrillary acidic protein compartmentalization.

Liver fat-storing cell clones obtained from a CCl4-cirrhotic rat are heterogeneous with regard to proliferation, expression of extracellular matrix components, interleukin-6, and connexin 43

BACKGROUND

Immunocytochemical analysis of liver has revealed that fat-storing cells (FSC) are heterogeneous with regard to vitamin A content, staining for cytokeratins, desmin, and vimentin and the cytoskeletal protein alpha-smooth muscle actin. Since fat-storing cells play an important role in collagen deposition in normal and cirrhotic liver, we considered it important to study whether fat-storing cells were heterogeneous with regard to cell proliferation, expression of mRNAs coding for cytokines interleukin-6 (IL-6) and transforming growth factor-beta (TGF-beta), and extracellular matrix components alpha 1(I), alpha 1(III), alpha 1(IV) procollagens, laminin B1 chain and fibronectin.

EXPERIMENTAL DESIGN

We used a FSC line (CFSC) that was developed in our laboratory after spontaneous immortalization of a primary culture of fat-storing cells that were obtained from the liver of a CCl4-cirrhotic rat (Lab. Invest. 65:644-653, 1991). The cells were cloned by limiting dilution and have been maintained in culture for over 3 years without appreciable changes in the parameters investigated.

RESULTS

In this communication we report the characterization of 4 of the clones obtained. We show that they are heterogeneous with regard to proliferation index, expression of alpha 1(I), alpha 1(III) and alpha 1(IV) procollagen, IL-6 and TGF-beta mRNAs. The clones also differ in their response to IL-6. We also showed that clones are coupled through functional gap junctions but that they are heterogeneous with regard to the expression of the gap junction protein connexin 43.

CONCLUSIONS

We suggest that clonal heterogeneity of FSC may occur in vivo. Since each of the clones expresses a unique phenotype, these FSC clones could be excellent models to study the role of defined extracellular matrices on the expression of liver specific genes by cultured hepatocytes.

Electrogenicity of the frog gastric mucosa proton pump based on polarization responses in the presence of H(+)-secretion inhibitors

Recently, we have shown that polarization of an electrogenic H+/K(+)-ATPase pump located in the secretory (luminal) membrane of the frog gastric mucosa is the major factor contributing to the increase in open circuit potential difference (OCPD) induced by voltage clamping. While this transmucosal polarization was not affected by removal of Cl- and Na+ and minimally affected by increasing the K+ concentration to 79 mM in both nutrient and secretory solutions, it was markedly reduced by 10(-3) M famotidine (beta blocker) or 10(-4) M omeprazole (H+/K(+)-ATPase inhibitor) in the nutrient solution. In present experiments, the effects of three other inhibitors of H+ secretion were examined, namely, cimetidine (beta blocker), SCH 28,080 (H+/K(+)-ATPase inhibitor) and SCN- (non-specific inhibitor). While cimetidine and SCH 28,080 markedly reduced the polarization induced by voltage clamp, SCN- affected the polarization to a lesser extent. These data further support the electrogenicity of the frog gastric mucosa proton pump and the lack of a direct effect of SCN- on the pump.

A transglutaminase that converts interleukin-2 into a factor cytotoxic to oligodendrocytes

Regenerating optic nerves from fish produce a factor that is cytotoxic to oligodendrocytes. The cytotoxic factor is recognized by antibodies to interleukin-2 (IL-2) and has the apparent molecular size of a dimer of IL-2. An enzyme, identified as a nerve transglutaminase, was purified from regenerating optic nerves of fish and was found to catalyze dimerization of human IL-2. The dimerized IL-2, unlike monomeric IL-2, is cytotoxic to oligodendrocytes from rat brain in culture. The results suggest that posttranslational modification of a cytokine can alter its activity. Under conditions in which oligodendrocytes inhibit neuronal regeneration, dimerization of IL-2 might provide a mechanism to permit nerve growth.

Haplotype analysis to determine the position of a mutation among closely linked DNA markers

Positional cloning involves first finding linkage between an inherited phenotype (such as a disease) and a DNA marker, followed by the use of a variety of physical and genetic mapping techniques to move from linkage to mutation. If there is a founder effect within a population, crossovers are often rare between the mutation causing the phenotype and closely situated markers and increasing disequilibrium may be observed as the site of the mutation is approached. Standard coefficients of disequilibrium may, however, be insensitive to the relative position of close markers and the mutation, because they depend upon allele frequencies in the normal population compared to those of the founder chromosome. Using cystic fibrosis in European populations as a model system, alternative methods for determining the position of a mutation are discussed. These include haplotype parsimony and three-way interval likelihood analysis. Both methods predict the location of the major CF mutation accurately from a real set of more than 600 European CF chromosomes.

Frequency of the delta F508 and exon 11 mutations in Norwegian cystic fibrosis patients

We have searched for the delta F508 mutation in 77 Norwegian cystic fibrosis patients. Of the 154 chromosomes tested, 93 (60%) carried the delta F508 mutation. Haplotypes at the D7S23 locus (KM19 and XV2C markers) were determined. Of 81 chromosomes with the F508 mutation, the B haplotype was found on 77. We found three patients with the G551D and one patient with the R553X mutation in exon 11 of the CFTR locus.