FLEXGene repository: from sequenced genomes to gene repositories for high-throughput functional biology and proteomics

The vast amount of information generated by the human genome sequencing project and related projects has given rise to a new paradigm in experimental biology. This new paradigm invokes the experimentation and data analysis at genome-wide scales, as well as the generation of new technologies and resources that take full advantage of the available sequence information. The Institute of Proteomics at Harvard Medical School is building a comprehensive, characterized, arrayed and flexible gene repository that will allow full exploitation of the genomic information by enabling functional genomics as well as protein expression, purification and analysis at genome wide scale. The FLEXGene repository (Full Length EXpression-ready) will contain clones representing the complete set of open reading frames (ORFs) of different organisms including H. sapiens and several pathogens and model organisms. The clones are constructed using recombination-based cloning technology so that hundreds or thousands of coding regions can be transferred into any expression vector in a parallel and timely mode, allowing the broadest variety of experiments to be carried out.

[Quantitative occurrence of lipolytic and proteolytic enzymes in food of animal origin]

Proteolytic and lipolytic enzymatic activities of microorganisms are the most important cause for food spoilage and a limited shelf life. Until now the determination of the total aerobic count is the base of shelf life evaluations. Our investigations show the proportion of proteolytes and lipolytes to the total germ count in different kinds of food (milk and milk products, meat products and fish) which is in part surprisingly high. Results were observed on different media--proteolytic germs were counted on protein containing agar (casein, meat protein, fish protein) and lipolytic organisms on fat containing agar (tributyrin, olive oil, butterfat). Using the predictive microbiology and the knowledge about the activity of microbial enzymes under different milieu conditions in food the results give an important tool for a better shelf life evaluation.

Maturation of Pseudomonas aeruginosa Elastase

Elastase of Pseudomonas aeruginosa is synthesized as a preproenzyme. After propeptide-mediated folding in the periplasm, the proenzyme is autoproteolytically processed, prior to translocation of both the mature enzyme and the propeptide across the outer membrane. The formation of the two disulfide bonds present in the mature enzyme was examined by studying the expression of the wild-type enzyme and of alanine for cysteine mutant derivatives in the authentic host and in dsb mutants of Escherichia coli. It appeared that the two disulfide bonds are formed successively. First, DsbA catalyzes the formation of the disulfide bond between Cys-270 and Cys-297 within the proenzyme. This step is essential for the subsequent autoproteolytic processing to occur. The second disulfide bond between Cys-30 and Cys-57 is formed more slowly and appears to be formed after processing of the proenzyme, and its formation is catalyzed by DsbA as well. This second disulfide bond appeared to be required for the full proteolytic activity of the enzyme and contributes to its stability.

Switch to efavirenz in a protease inhibitor-containing regimen

PURPOSE

This report evaluated the efficacy and safety of switching from a protease inhibitor (PI)-containing HIV treatment regimen to an efavirenz (EFV)-containing regimen.

METHOD

We retrospectively analyzed data from 64 patients, with a plasma viral load (VL) less than 50 copies/mL and CD4+ counts >200 cells/mL at baseline, who had been taking a regimen consisting of a PI and two nucleoside reverse transcriptase inhibitors (NRTIs; d4T/3TC [n = 45]; AZT/3TC [n = 19]) for a median of 27.5 months (range, 6-41 months) and who chose to substitute EFV for the PIs in the regimens. Statistical analyses were performed by Wilcoxon test. Fat atrophy was evaluated by physician's assessment and patients' subjective self-estimation with the criteria of well being and body state.

RESULTS

57 patients completed 36 weeks on the EFV regimen; 4 patients changed therapy but continued EFV, 2 moved to another area, and 1 discontinued EFV. During the first weeks of therapy, 56.3% of patients suffered from moderate nervous system symptoms. The plasma VL of 63 patients remained at <50 copies/mL at final analysis. Compared with time of switching to EFV, analysis at 36 weeks showed no statistically significant change from 626+/-283 to 643+/-296 cells/mL in mean absolute CD4+ cells and a statistically significant increase from 26.8+/-9.6% to 28.0+/-9.1% in relative CD4+ cells. There was a statistically significant reduction in relative CD8+CD38+ from 62.2+/-16.3% at time of switching to EFV to 55.1+/-15.0% at week 36. At baseline, 27 patients suffered from lipodystrophy, including fat atrophy and fat accumulation. After 36 weeks, nine patients showed intensified fat atrophy. In contrast, five patients improved their state concerning fat redistribution and 13 patients showed no alterations.

CONCLUSION

The switch to a non-PI-containing regimen with EFV offers a good drug alternative for patients with suppressed viral load, problems of adherence, and/or adverse events due to PIs but not for patients suffering from lipoatrophy caused by nucleoside reverse transcriptase inhibitors. The intention of such a switch aims at the avoidance of fatal mutations in HIV.

Cloning of a catalytic subunit of cAMP-dependent protein kinase from the honeybee (Apis mellifera) and its localization in the brain

In the honeybee the cAMP-dependent signal transduction cascade has been implicated in processes underlying learning and memory. The cAMP-dependent protein kinase (PKA) is the major mediator of cAMP action. To characterize the PKA system in the honeybee brain we cloned a homologue of a PKA catalytic subunit from the honeybee. The deduced amino acid sequence shows 80-94% identity with catalytic subunits of PKA from Drosophila melanogaster, Aplysia californica and mammals. The corresponding gene is predominantly expressed in the mushroom bodies, a structure that is involved in learning and memory processes. However, expression can also be found in the antennal and optic lobes. The level of expression varies within all three neuropiles.

Occult micro medullary thyroid carcinoma: therapeutic strategy and follow-up

Twenty micro medullary thyroid carcinomas (MTCs) were found in histologic specimens of 19 patients in our department from 1990 to 1998. There were 14 women and 5 men, with a median age of 63 years. The indication for surgery was goiter in 12 patients and a solitary nodule in 7 patients (three differentiated cancers). Altogether, 18 patients had unifocal micro-MTCs with a median diameter of 3.6 mm. One patient had a bilateral MTC (3 and 5 mm, respectively). Surgical procedures consisted of 9 total thyroidectomies and 10 lobectomies or subtotal thyroidectomies. Of these 10 patients, 4 underwent reoperation (totalization). One was operated on 48 months after a positive pentagastrin test: There was no thyroid residual tumor but three lymph node micrometastases. Among the six patients in whom thyroid tissue was left, a 91-year-old woman died of unrelated cause and the five others remain disease-free without biologic abnormalities at follow-ups of 18 to 70 months. Considering the aggressiveness of MTCs, total thyroidectomy with central compartment dissection is theoretically indicated. However, among the nine total thyroidectomies and four secondary totalizations associated with at least central compartment dissection, no other thyroid lesion was observed and only one case of lymph node microinvasion was found. Because of the morbidity associated with reoperation and neck dissection, we propose that it is indicated only for microcarcinomas > 5 mm in diameter, in cases of an abnormal response to pentagastrin, or when it is difficult to ensure prolonged follow-up of the patient.

Combinatorial roles for pRB, p107, and p130 in E2F-mediated cell cycle control

Numerous studies have implicated the pRB family of nuclear proteins in the control of cell cycle progression. Although over-expression experiments have revealed that each of these proteins, pRB, p107, and p130, can induce a G(1) cell cycle arrest, mouse knockouts demonstrated distinct developmental requirements for these proteins, as well as partial functional redundancy between family members. To study the mechanism by which the closely related pRB family proteins contribute to cell cycle progression, we generated 3T3 fibroblasts derived from embryos that lack one or more of these proteins (pRB(-/-), p107(-/-), p130(-/-), pRB(-/-)/p107(-/-), pRB(-/-)/p130(-/-), and p107(-/-)/p130(-/-)). By comparing the growth and cell cycle characteristics of these cells, we have observed clear differences in the manner in which they transit through the G(1) and S phases as well as exit from the cell cycle. Deletion of Rb, or more than one of the family members, results in a shortening of G(1) and a lengthening of S phase, as well as a reduction in growth factor requirements. In addition, the individual cell lines showed differential regulation of a subset of E2F-dependent gene promoters, as well as differences in cell cycle-dependent kinase activity. Taken together, these observations suggest that the closely related pRB family proteins affect cell cycle progression through distinct biochemical mechanisms and that their coordinated action may contribute to their diverse functions in various physiological settings.

[Volumetry of the urinary bladder with implantable ultrasound sensors]

Experimental studies revealed that the contractile response of the urinary bladder to sacral anterior root stimulation depends on the actual bladder volume. Furthermore, no clinical relevant technique is available for continuous monitoring of the bladder wall distension respectively bladder volume in paraplegic patients. The presented study investigates the reliability of especially developed implantable ultrasound sensors as a sensoric system for continuous monitoring of the bladder volume. In six anaesthesized pigs two ultrasound sensors, one transmitter and one receiver, were implanted on the bladder wall at different locations (latero-lateral, dorsal-ventral, rostral-caudal). After closing the abdominal wall, the bladder was filled in 50 ml steps up to 250 ml. After each filling step the running time of the ultrasound signal was measured. In all experiments reproducible results and a high correlation of the measured running times with bladder volume were observed. The latero-lateral configuration of the sensors seemed to be most confidential. The presented study indicates that bladder volumetry with implantable ultrasound sensors is possible with minimal technical prerequisites. This promising technique for continuous bladder volumetry could play an important role in the development of an intelligent and autoadaptive neurostimulator of the urinary bladder in paraplegic patients.

The potential to use PspA and other pneumococcal proteins to elicit protection against pneumococcal infection

Pneumococcal proteins, alone, in combination with each other, or in combination with capsular polysaccharide-protein conjugates may be useful pneumococcal vaccine components. Four proteins with a potential for use in vaccines are PspA, pneumolysin, PsaA, and PspC. In a mouse model of carriage, PsaA and PspC were the most efficacious vaccine proteins. Of these, PsaA was the best at eliciting protection against carriage. However, a combination of PspA and pneumolysin may elicit stronger immunity to pulmonary infection and possibly sepsis than either protein alone. Recently, a phase one trial of a recombinant family 1 PspA was completed in man. PspA was observed to be safe and immunogenic. Injection of 0.1 ml of immune serum diluted to 1/400 was able to protect mice from fatal infection with S. pneumoniae. Under these conditions, pre-immune serum was not protective. The immune human serum protected mice from infections with pneumococci expressing either of the major PspA families (1 and 2) and both of the pneumococcal capsular types tested: 3 and 6.

[Persistence of Chlamydia pneumoniae in coronary plaque tissue. A contribution to infection and immune hypothesis in unstable angina pectoris]

BACKGROUND AND OBJECTIVE

There is an increasing number of pointers towards a causative connection between Chlamydia pneumoniae and atherosclerosis. But the pathogenetic mechanism and intimal structures that are involved remain unclear. Starting with the hypothesis of a chronic infection, as demonstrated by the presence of the chlamydial stress (heat-shock) protein 60 (HSP 60), the presence and localization of these bacterial products in coronary atheromas was investigated.

PATIENTS AND METHODS

Coronary atheroma tissue from primary stenoses in 42 patients (36 men, 6 women, mean age 60.2 +/- 7.3 years) was studied immunohistochemically in the course of a retrospective analysis for chlamydial HSP 60. The findings in clinically acute coronary syndrome (Braunwald's classification) present in 27 patients were compared with those in 15 patients with acute angina and evaluated in relation to expression and site of predilection.

RESULTS

An immune reaction to chlamydial HSP 60 was demonstrated in 27 of 42 atheromas (64%). Intact, non-atherosclerotic vessels, such as the mammary artery and sphenous vein, showed no such signals. Chlamydial HSP 60 was localized in maximally 23% of all plaque cells, mostly in macrophages/foam cells, more rarely in smooth muscle cells. Chlamydia in foam cells most often revealed ultrastructural patterns that pointed to the persistence of the pathogen. Sites of predilection of chlamydial HSP were predominantly foam cell areas and cell-poor regions, more rarely inflammatory infiltrates and areas of rupture. When comparing both types of lesion, signals for chlamydial HSP 60 were present in 21 of the 27 atheromas (78%) with unstable angina or acute myocardial infarction, but in only 6 of the 15 atheromas (40%) with stable angina. Within the group with the acute coronary syndrome, the prevalence of chronic chlamydial infection was independent of a previous myocardial infarction.

CONCLUSIONS

Chlamydial HSP 60 can often be demonstrated in primary coronary stenosis of symptomatic patients. It is most frequently found in macrophages/foam cells and is highly prevalent in the acute coronary syndrome. In-situ findings suggest a pathogenetically relevant role of chronic persistent infection of Chlamydia pneumoniae in unstable coronary plaques.

Recording the evoked canine detrusor electromyogram

With increasing interest in detrusor disorders and possible detrusor myopathies, a method for recording the detrusor electromyogram (detrusor-EMG) would probably greatly assist the diagnosis of various bladder dysfunctions. Therefore, we investigated the electromyographic activity of the detrusor during sacral root stimulation and during spontaneous bladder contractions in six anesthetized dogs. In all experiments, a high correlation of detrusor-EMG recordings with bladder contraction was observed. Analysis in the time domain and power spectrum analysis revealed the most clear correlation of detrusor-EMG with intravesical pressure rise in a frequency band above 3 Hz. The spike duration was 100 to 250 ms with an amplitude of 100 to 500 microV. Low-frequency activity below 1 Hz was mainly presumed to be artifacts due to fluid movement under the electrode. Our trials indicate that smooth muscle EMG recordings from the detrusor smooth musculature are possible. The exact physiological relevance of the signal in the sub-Hertz domain (<1 Hz) is still uncertain. The presented animal model allows the pathophysiologic investigation of various pathologies of bladder dysfunction and detrusor myopathies. Neurourol. Urodynam. 18:687-695, 1999.

[Coil embolization of an AV-fistula between the left thoracic artery and vein after coronary artery bypass surgery]

We report a case of an artificial fistula between the internal thoracic artery and vein after coronary artery bypass surgery, anastomosing the left internal thoracic artery to the LAD. Because of symptomatic anterior wall ischaemia due to coronary steal a treatment was mandatory. Instead of surgical correction, this shunt was closed by coil embolization of the venous limb.

Improving protein secretion by engineering components of the bacterial translocation machinery

The increased insight into the mechanism of bacterial protein translocation has resulted in new concepts for the production of heterologous proteins. The periplasm of gram-negative bacteria is revealed to have a role as a 'protein construction compartment', which can be used to fold complex proteins. Passage across the outer membrane, however, remains a challenge due to the high selectivity of the outer membrane translocase. In gram-positive bacteria, slow folding at the membrane-cell-wall interface can make heterologous proteins vulnerable to degradation by wall-associated proteases. The recent identification of thiol-disulfide oxidoreductases in Bacillus subtilis might open the possibility of secreting proteins containing multiple disulfide bonds from this host.

The aromatic residues Trp and Phe have different effects on the positioning of a transmembrane helix in the microsomal membrane

We have examined the effect of Trp and Phe residues on the positioning of a poly-Leu transmembrane helix relative to the microsomal membrane by employing a previously described "glycosylation mapping" technique [Nilsson, I. M., Sääf, A., Whitley, P., Gafvelin, G., Waller, C., and von Heijne, G. (1998) J. Mol. Biol. 284, 1165-1175]. Both Trp and Phe tend to push the transmembrane helix into the membrane when inserted in positions flanking the poly-Leu stretch, and Trp (but not Phe) pulls the transmembrane helix toward the lipid-water interface when inserted inside the poly-Leu segment. Thus, the preference of Trp for the lipid-water interface previously suggested on the basis of biophysical studies of model peptides can also be observed for a bona fide transmembrane helix in a biological membrane. We further show that a sufficiently long poly-Trp segment functions as an efficient stop-transfer sequence during protein translocation across the microsomal membrane, despite the preference of Trp residues for the lipid-water interface region.

Information needs in a changing health care system: capitation and the need for a population-oriented view

Information systems needed for managing the health care of populations under at-risk (capitation) contracts must be designed differently than those used in fee-for-service practice. Under capitation, providers must deliver health care to enrollees with financial resources that are fixed in advance. Therefore, the information systems they use must enable them to understand the health status of health plan enrollees and how health care is provided. These systems should facilitate the detection of underservice and of inadequate quality of health care as well as overuse of health care resources. They should permit clinical-epidemiologic and statistical analysis; facilitate disease management and the adoption of preventive programs, and lend themselves to use by planners, group leaders, and practicing physicians.

Long-term followup and selection criteria for penile revascularization in erectile failure

PURPOSE

We report the long-term results of penile revascularization surgery for erectile failure and suggest possible selection criteria for this controversial surgical procedure.

MATERIALS AND METHODS

In 7 years 62 impotent men who did not respond to pharmacotherapy underwent microsurgical penile revascularization and completed long-term followup evaluation in 41 months (range 18 to greater than 62) consisting of a detailed questionnaire, duplex sonography and optional pharmacotherapy or angiography. The Virag procedure was chosen for the first 7 patients, the original Hauri technique for the next 13 and the modified Mannheim triple anastomosis for 42.

RESULTS

Of all patients 34% achieved spontaneous and another 20% pharmacologically induced erections. Success in diabetics and older patients was lower (43% for diabetics, 39% for those older than 50 years at surgery), while it was high in men with less than 2 risk factors (58%) as well as in younger patients (69% for those up to 50 years old). Shunt patency was 92%. Complications such as glans hyperemia developed in 13% of patients, shunt thrombosis in 8% and inguinal hernias in 6.5%.

CONCLUSIONS

Patient selection is vital for the successful outcome of penile revascularization surgery. We adhere to strict selection criteria, such as patient age maximum of 50 years, less than 2 risk factors, no recent diabetes and termination of nicotine abuse. Penile revascularization surgery is highly indicated in this group of patients, especially since it is the only causal therapy for erectile failure.

Effects of glycosylation on fragments of tumour associated human epithelial mucin MUC1

The glycodecapeptide AcPAPGS(alpha GalNAc)T(alpha GalNAc)APPA and the C-terminal glycohexapeptide AcS(alpha GalNAc)T(alpha GalNAc)APPA have been synthesized by applying the N-terminal Fmoc group in combination with the heptyl ester cleavable by lipase-catalyzed hydrolysis at pH 7. The solution conformation of these MUC1-related synthetic glycopeptides and the control, non-glycosylated decapeptide AcPAPGSTAPPA have been investigated using NMR spectroscopy. The structural studies indicate that the glycohexapeptide has a folded structure in solution. For this molecule, unrestrained molecular dynamics has been used to confirm the presence of the observed solution through-space connections. The results indicate that the non-globular nature of MUC1 is due to both protein core sequence and the effect of carbohydrate.

Effect of HELP-LDL-apheresis on outcomes in patients with advanced coronary atherosclerosis and severe hypercholesterolemia

In the secondary prevention of coronary artery disease (CAD) the beneficial effect of lipid lowering is no longer controversial. LDL-apheresis is a feasible therapy for effective lipid lowering in patients refractory to diet and cholesterol lowering drugs. To assess the impact of the HELP-therapy (heparin-induced, extracorporeal LDL precipitation) on patients' clinical outcome and coronary angiography, we set up a prospective trial, in which patients with advanced coronary atherosclerosis and severe hypercholesterolemia resistant to diet and drug therapy were treated with LDL-apheresis. A total of 44 patients were treated with adjunctive weekly HELP-therapy for 15.5 +/- 9.5 months. The mean levels of total cholesterol (Chol), LDL-cholesterol (LDL-C), Lp(a), and fibrinogen at baseline were 308.0 +/- 69.7, 231.8 +/- 72.7, 82.2 +/- 54.1, and 356.1 +/- 94.1 mg/dl, respectively. LDL-apheresis caused a mean per treatment reduction of 44.8 +/- 8.7, 55.5 +/- 8.6, 60.8 +/- 10.2, and 53.8 +/- 6.5% of Chol, LDL-C, Lp(a), and fibrinogen, resulting in mean treatment interval values of 190.4 +/- 33.7, 116.3 +/- 28.9, 51.9 +/- 33.1, and 213.7 +/- 148.9 mg/dl, respectively. Improvement of the clinical status (exercise tolerance, anti-anginal drug use, angina pectoris) was found in 73%, no change in 11%, and deterioration in 16% of the cases. Four patients died cardiac death. The maximal bicycle exercise work load of the patients increased significantly from 101 +/- 41 to 119 +/- 46 W (P < 0.001). Ten (40%) out of 25 patients who underwent follow-up angiography revealed CAD progression, whereas two (8%) patients had CAD regression. Despite angiographic deterioration eight out of ten progressors (80%) improved clinically. In patients with advanced coronary atherosclerosis and severe hypercholesterolemia HELP-therapy can safely and effectively lower LDL-C, Lp(a), and fibrinogen. The chronic weekly HELP-treatment results in clinical improvement in the majority of patients, even in those patients with angiographically shown CAD progression.

Secretion of elastinolytic enzymes and their propeptides by Pseudomonas aeruginosa

Elastase of Pseudomonas aeruginosa is synthesized as a preproenzyme. The signal sequence is cleaved off during transport across the inner membrane and, in the periplasm, proelastase is further processed. We demonstrate that the propeptide and the mature elastase are both secreted but that the propeptide is degraded extracellularly. In addition, reduction of the extracellular proteolytic activity led to the accumulation of unprocessed forms of LasA and LasD in the extracellular medium, which shows that these enzymes are secreted in association with their propeptides. Furthermore, a hitherto undefined protein with homology to a Streptomyces griseus aminopeptidase accumulated under these conditions.

[Combined effect of temperature a(W) and pH on proteases from Pseudomonas and Bacillus spp]

The factors affecting protease activity were investigated on certain media. Five strains of Bacillus (B.) cereus, four strains of B. subtilis, five strains of Pseudomonas (Ps.) aeruginosa and two strains of Ps. fluorescens produced the proteases that were tested. The enzyme activity was evaluated under 32 different combinations of temperature (2 and 7 degrees C), water activity (aw) (0.80-0.98) and pH (4.0-7.3). A decrease in water activity and pH and/or temperature caused a decrease in protease activity. It appeared that the combined effect of temperature, aw and pH influences enzyme production significantly compared with the influence of single environmental factors. Temperature plays the crucial role in these reactions. Enzyme activities could be observed even at low temperature. Although the exoprotease of Ps. spp. showed intense activity at refrigeration temperature, low pH and aw, Bacillus proteases were comparably less active under the same conditions, but nevertheless proved to be significant.

Alanine insertion scanning mutagenesis of lactose permease transmembrane helices

A priori, single residue insertions into transmembrane helices are expected to be highly disruptive to protein structure and function. We have carried out a systematic analysis of the phenotypes associated with Ala insertions into transmembrane helices in lactose permease, a multispanning Escherichia coli inner membrane protein. Insertion of alanine into the center of 7 transmembrane helices was found to abolish stable integration of lactose permease into the membrane or uphill lactose transport. A more detailed Ala insertion scan was made of transmembrane helix III. The results pin-point a central region of approximately 2 helical turns that is crucial for lactose permease stability and/or activity. A Trp scan in this region identified 2 residues essential for lactose permease stability. From these results, it appears that transmembrane helices have differential sensitivities to single residue insertions and that such mutations may be useful for identifying structurally and/or functionally important helix segments.

Regression of transplant coronary artery disease during chronic low-density lipoprotein-apheresis

BACKGROUND

The pathogenesis of transplant coronary artery disease (TxCAD) is probably multifactorial. Immune mechanisms may be the primary and triggering stimuli, whereas risk factors such as hyperlipoproteinemia or lipoprotein(a) elevation may accelerate the progression of the disease. With the heparin-induced-low-density lipoprotein-precipitation (HELP), low-density lipoprotein (LDL), fibrinogen, and lipoprotein(a) can be reduced about 55%, 50%, and 60%, respectively.

METHODS

We treated eight heart transplant recipients (52.6 +/- 8.1 years old; all men) with weekly LDL-apheresis (HELP-system). At the beginning of the HELP treatment, all patients had survived at least 2 years after surgery, had LDL levels higher than 150 mg/dl in spite of 10 mg pravastatin per day and diet, and had development of significant coronary artery disease as shown by annual coronary angiography. We analyzed three angiograms in each patient taken 16.2 +/- 6.5 months before, at the beginning of (-0.5 +/- 6 months), and after 21.8 +/- 7.4 months of HELP therapy. Two hundred seventy-three coronary artery segments (34 +/- 6 per patient; 6 to 65 single measurements per segment) were analyzed by quantitative coronary angiography. Statistical significances of differences between the angiograms taken at the three time points were evaluated by the paired t test.

RESULTS

Measurements of all coronary artery segments showed a significant decrease of mean luminal diameter during the last 1 to 2.5 years before the HELP treatment from 3.61 +/- 1.1 mm to 3.15 +/- 1 mm (p < 0.0001). During the following 1 to 2.5 years of HELP therapy, the mean luminal diameter increased to 3.4 +/- 1.15 mm (p < 0.0001).

CONCLUSIONS

In long-term heart transplantation survivors with hyperlipidemia, who have development of a rapid progressive coronary artery disease, LDL-apheresis can lead to disease regression. Further studies will be needed to determine whether immunologic factors and growth factors involved in the TxCAD pathogenesis are also eliminated by the HELP therapy and whether HELP is also effective in patients with TxCAD without severe hypercholesterolemia.

SAPALDIA: methods and participation in the cross-sectional part of the Swiss Study on Air Pollution and Lung Diseases in Adults

SAPALDIA--the Swiss Study on Air Pollution and Lung Diseases in Adults--focuses on the long term health effects of low to moderate levels of air pollutants as typically seen in different parts of Switzerland. The aim of the SAPALDIA cross-sectional study carried out in 1991 was to determine the prevalence of bronchial asthma, chronic bronchitis and allergic conditions in the adult population of Switzerland and to identify and to determine the respective importance of potentially influencing factors. These could be both personal (smoking habits, allergy status, family history, occupation) and environmental (outdoor and indoor pollution, aeroallergens, climate). A further aim of the cross-sectional study consisted in the identification of individuals susceptible to present symptoms during a two year observation period and to be included in the SAPALDIA follow-up study. This technical report represents the methodological documentation for the cross-sectional study of SAPALDIA. The instruments and the methods of standardisation are presented and discussed. The medical examination consisted of a computerised interview using a standardised questionnaire, the taking of a blood sample for serological tests, allergy skin testing, the measurement of end expiratory CO and body height, and pulmonary function testing followed by methacholine challenge testing or bronchodilatation testing. The pattern of participation and the 9651 participants of the study, representing 59.3% of the sample, are described. Based on information on non-participants gained by telephone interviews and mailed short questionnaires, possible selection biases are quantified and discussed.

Predicting the presence of plasma heparin using neural networks to analyze coagulation screening assay optical profiles

A method for predicting the presence of heparin from coagulation screening assays is described and data are presented. This method incorporates the use of a multilayer perceptron trained through an error back-propagation algorithm in analyzing clotting optical data profiles. This method may lead to the identification of abnormalities from screening assays that might otherwise go undetected, or require additional testing to isolate.

Genetic characterization of a mammalian protein-protein interaction domain by using a yeast reverse two-hybrid system

Many biological processes rely upon protein-protein interactions. Hence, detailed analysis of these interactions is critical for their understanding. Due to the complexities involved, genetic approaches are often needed. In yeast and phage, genetic characterizations of protein complexes are possible. However, in multicellular organisms, such characterizations are limited by the lack of powerful selection systems. Herein we describe genetic selections that allow single amino acid changes that disrupt protein-protein interactions to be selected from large libraries of randomly generated mutant alleles. The strategy, based on a yeast reverse two-hybrid system, involves a first-step negative selection for mutations that affect interaction, followed by a second-step positive selection for a subset of these mutations that maintain expression of full-length protein (two-step selection). We have selected such mutations in the transcription factor E2F1 that affect its ability to heterodimerize with DP1. The mutations obtained identified a putative helix in the marked box, a region conserved among E2F family members, as an important determinant for interaction. This two-step selection procedure can be used to characterize any interaction domain that can be tested in the two-hybrid system.

Managed care and the infectious diseases specialist

There is growing demand to contain health care costs and to reassess the value of medical services. The traditional hospital, academic, and research roles of the infectious disease (ID) specialist are threatened, yet there is an increasing need for expertise because of growing antimicrobial resistance and emerging pathogens. Opportunities exist to develop and expand services for the care of patients infected with human immunodeficiency virus and in infection control, epidemiology, outcomes research, outpatient intravenous therapy, and resource management. It is important for ID physicians to appreciate the principles involved in managed care and the areas in which ID services can be valuable. To be effective, physicians need to know about tools such as practice guidelines, physician profiling, outcomes monitoring, computerized information management, risk sharing, networking, and marketing, as well as related legal issues. With a positive attitude toward learning, application, and leadership, ID physicians can redefine their role and expand their services through managed care.

Developing staff nurse experts in nursing diagnosis-based care planning

In this article, the authors describe the Program to Increase Nursing Knowledge and Facilitate the Utilization of Nursing Diagnosis (PINK FUND) undertaken at the Medical College of Virginia Hospitals. The program prepared unit-based nurses to be facilitators for nursing diagnosis-based care planning. Major curriculum threads included theory of nursing diagnosis, planned change, and adult learning. Instructors modeled innovative instructional methodologies for participants. Program planners vigorously marketed the program to nurses within the institution. The program succeeded in preparing nurses to use the nursing process to deliver planned care. The program description will serve as a potential model for staff development educators seeking to increase staff competence in nursing care planning and documentation.

Lipid disorder and transplant coronary artery disease in long-term survivors of heart transplantation

BACKGROUND

Transplant coronary artery disease is the major cause of late mortality after heart transplantation. The underlying mechanism probably involves various factors including immunologic and nonimmunologic factors.

METHODS

The influence of various risk factors concerning both the development and the progression of transplant coronary artery disease was analyzed. Fifty-two heart transplant patients, who survived at least 2 years after transplantation (24 to 60 months), were included.

RESULTS

Of these patients 38.5% had angiographic evidence of transplant coronary artery disease. They had significantly higher values of total cholesterol, low-density lipoprotein cholesterol, and log triglycerides than patients without evidence of the disease (p = 0.037, p = 0.002, and p = 0.015, respectively). In addition, preoperative diagnosis of coronary artery disease was a predictor of the development of transplant coronary artery disease, whereas significant differences were not found corresponding to recipient age, donor age, ischemic time, body mass index, lipoprotein (a) value, high-density lipoprotein cholesterol value, time after transplantation, number of postoperative rejection episodes, or prednisone dosage. A 12-month angiographic follow-up indicated disease progression in 25% of the patients. With respect to the majority of factors analyzed within the study, the differences between patients with and those without progression were comparable to the differences between patients in whom transplant coronary artery disease developed and those in whom it did not. However, patients exhibiting disease progression had a higher prednisone intake dosage (p = 0.006) and had significantly higher lipoprotein (a) values (p = 0.0229) than patients without progression.

CONCLUSION

This study clearly shows that in heart transplant patients surviving more than 2 years, lipid disorder is one of the main risk factors of both the development and the progression of transplant coronary artery disease.

Possible Role of Cbr, an Algal Early-Light-Induced Protein, in Nonphotochemical Quenching of Chlorophyll Fluorescence

The unicellular green alga Dunaliella bardawil exhibits typical responses to excessive light when starved for sulfate under normal light (60 [mu]E m-2 s-1) but not under low light (14 [mu]E m-2 s-1). Algae were analyzed during several days of sulfate starvation for nonphotochemical quenching of chlorophyll fluorescence in the absence or presence of the uncouplers SF-6847 (SF) or carbonyl cyanide p- trifluoromethoxyphenyl hydrazone. Parallel analyses followed two light-stress responses: (a) violaxanthin conversion to zeaxanthin and (b) accumulation of Cbr, a protein analogous to plant early-light-induced proteins and implicated in zeaxanthin binding. In cells starved under normal light SF inhibited nonphotochemical quenching during the first 24 h, but not from 40 h onward. In cells starved under low light SF inhibited nonphotochemical quenching throughout the starvation period. Under normal light accumulation of zeaxanthin was nearly maximal by 24 h, but Cbr was fully induced only by 40h. Under low light zeaxanthin accumulated slowly but no Cbr was evident. These results suggest that during exposure to excessive light, the initial pH gradient-dependent, Cbr-independent mode of nonphotochemical quenching is modified to become less dependent on pH gradient and requires Cbr.

Role of the propeptide in folding and secretion of elastase of Pseudomonas aeruginosa

Elastase of Pseudomonas aeruginosa is synthesized as a pre-proprotein. The propeptide has been shown to inhibit the enzymatic activity of elastase. In this study, we investigated a possible additional role of the propeptide in the folding and secretion of the enzyme. When elastase was expressed in Escherichia coli without its propeptide, no active elastase was produced. The enzyme was poorly released from the cytoplasmic membrane and, depending on the expression level, it was either degraded or it accumulated in an inactive form in the cell envelopes, probably as aggregates. Since proper folding is required for the release of translocated proteins from the cytoplasmic membrane and for the acquirement of a stable and active conformation, these results suggest that the propeptide is involved in the proper folding of the elastase and that it functions as an intramolecular chaperone. When mature elastase was expressed without its propeptide in P. aeruginosa, the enzyme was not secreted, and it was degraded. Therefore, proper folding of mature elastase appears to be required for secretion of the enzyme. Expression of the propeptide, as a separate polypeptide, in trans with mature elastase resulted in the formation of active elastase. This active enzyme was secreted in P. aeruginosa. Apparently, the propeptide can also function as an intermolecular chaperone.

Accumulation of activated CD4+ lymphocytes in the lung of individuals infected with HIV accompanied by increased virus production in patients with secondary infections

The lung is continuously exposed to infectious and non-infectious agents causing cell activation. Activated cells in the lung such as antigen-presenting cells which harbour HIV may favour this organ as a site for virus production. To test this hypothesis, cells from blood and bronchoalveolar lavage (BAL) of HIV-infected patients and healthy controls were obtained and the activation of the cells were analysed by measuring the expression of IL-2 receptor, HLA-DR and VLA-1. The HIV-infected individuals were subdivided into 'lung symptomatic' or 'lung asymptomatic' patients, depending on the presence or absence of secondary lung diseases besides HIV. All HIV-infected individuals demonstrated a decreased number of CD4+ lymphocytes in blood; however, normal numbers of these cells were found in BAL. The activation state of CD4+ and CD8+ T lymphocytes in blood and BAL was higher in lymphocytes from HIV-infected patients compared with controls. The activation state was highest in the lung symptomatic group. Lung symptomatic patients and lung asymptomatic patients with extrapulmonary infections had increased levels of free virus in plasma. Four out of four individuals without or with only low amounts of cell-free HIV in plasma belonged to the symptom-free subgroup. These results suggest that microorganisms other than HIV may promote viral replication via antigen-driven accumulation and activation of CD4+ cells in the lung or other organs, and thus may be responsible for the loss of helper T cells and the progression of the disease.

Regression of transplant coronary artery disease during chronic HELP therapy: a case study

This report concerns a heart transplant patient with hypercholesterolemia who showed rapid development of a severe transplant coronary artery disease. The patient received 10 mg pravastatine per day. Quantitative coronary angiography analyses of 4 serial angiograms clearly demonstrated that in the first 2.5 years following surgery, there was a rapid simultaneous progression in both the transplant coronary disease, involving the entire coronary system, and the development of segmental stenotic lesions. During one year of weekly heparin-mediated extracorporeal LDL-cholesterol precipitation (HELP) therapy in addition to diet and pravastatine therapy, the serum low density lipoprotein (LDL), lipoprotein (a) (Lp(a)), and fibrinogen levels could be reduced from 185 +/- 45 mg/dl, 138 mg/dl and 248 mg/dl, respectively, to interval values of 136 +/- 17 mg/dl, 48 +/- 15 mg/dl, and 185 +/- 44 mg/dl, respectively [interval value = (the concentration after HELP + the concentration before the next HELP treatment):2]. This therapy halted further progression of coronary diameter throughout the whole coronary system and brought about marked regression of segmental obstructive lesions.

Migration of Salmonella enteritidis from the albumen into the egg yolk

Migration of Salmonella enteritidis from the albumen into the egg yolk was investigated in 860 eggs. After artificial contamination of the albumen with different doses of S. enteritidis phage-type 4 the migration and the effect of temperature on the migration process during a storage period of up to 4 weeks were studied. The experiments showed that the first cells can be detected in the yolk within a few days. The process will be relatively rare during chilled storage if the albumen is only slightly contaminated. The migration rate was positively correlated with the level of contamination, the storage temperatures and the age of the eggs.

Passive smoking exposure in adults and chronic respiratory symptoms (SAPALDIA Study). Swiss Study on Air Pollution and Lung Diseases in Adults, SAPALDIA Team

The association between passive exposure to tobacco smoke and respiratory symptoms was examined in a sample of 4,197 never-smoking adults. They constituted the never-smoking subsample of a random sample of 9,651 adults (age, 18 to 60 yr) in eight areas in Switzerland. Information on passive smoking exposure and standardized questions on respiratory symptoms were obtained via a questionnaire administered by trained examiners. After controlling for age, sex, body mass index (BMI), study area, atopy, and parental and sibling history, passive smoking exposure was associated with an elevated risk of wheezing apart from colds (odds ratio [OR] = 1.94, 95% CI = 1.39 to 2.70), an elevated risk of bronchitis symptoms (OR = 1.59, 95% CI = 1.17 to 2.15), an elevated risk of symptoms of chronic bronchitis (OR = 1.65, 95% CI = 1.28 to 2.16), an elevated risk of dyspnea (OR = 1.45, 95% CI = 1.20 to 1.76), and an elevated risk of physician diagnosed asthma (OR = 1.39, 95% CI = 1.04 to 1.86). It was not associated with any increased risk of allergic rhinitis including hayfever. Adding a variable for low educational level, excluding subjects whose mother ever smoked or subjects with end-expiratory CO levels > or = 7 ppm, and controlling for paternal smoking during childhood or occupational exposure had little impact on the association. The association of passive smoking exposure with dyspnea, wheeze, and asthma showed evidence of a dose-dependent increase with hours per day of exposure, whereas association with symptoms of bronchitis was stronger with years of exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Activated T cells and cytokines in bronchoalveolar lavages from patients with various lung diseases associated with eosinophilia

Increasing evidence suggests an important role for cytokines in the regulation of eosinophilic inflammation. In the present study we investigated the distribution of leukocytes, lymphocyte subsets, their activation state, and the cytokine profile present in BAL fluid from patients with various lung diseases associated with eosinophilia. For this purpose, we analyzed the levels of IL-1 beta, IL-2, IL-4, IL-5, IL-6, IL-8, GM-CSF, TNF-alpha, and IFN-gamma, as well as soluble IL-2 and TNF receptors, in concentrated bronchoalveolar lavage (BAL) fluid obtained from clearly defined patients with allergic and nonallergic asthma, eosinophilic pneumonia, allergic bronchopulmonary aspergillosis (ABPA), hypersensitivity pneumonitis, and idiopathic pulmonary fibrosis. BAL fluid from normal individuals and sarcoidosis patients was analyzed as noneosinophilic controls. BAL cytokine levels were compared with the cellular infiltrate and the activation state of CD4+ and CD8+ T cells as measured by the expression of IL-2 receptors (CD25), HLA-DR, and the very late activation antigen VLA-1. Beside the characteristic leukocyte infiltrate in the various lung diseases, all patients demonstrated significantly increased numbers of activated CD4 and CD8 T cells compared with normal individuals. The analysis of the cytokine profile present in BAL fluid revealed a T helper type 2 (Th2) cell cytokine pattern, with elevated IL-4 and IL-5 but normal levels of IL-2 or IFN-gamma in allergic asthma. ABPA patients demonstrated significantly increased levels of IL-4 and IL-5, with low but significantly elevated concentrations of IL-2 and IFN-gamma. In contrast, the analysis of the cytokine profile in sarcoidosis patients revealed a Th1 cell cytokine pattern characterized by increased concentrations of IL-2 and IFN-gamma but normal levels of IL-4 or IL-5. All other patient groups showed a cytokine pattern incompatible with a pure Th1 or Th2 cell response, because IL-5, IL-2, and IFN-gamma were found to be significantly increased. The BAL fluid analysis of the other, mainly non-T cell-derived cytokines and soluble receptors showed increased levels in all patients compared with normal individuals and may represent the ongoing inflammatory responses. In conclusion, whereas increased IL-4 levels were found only in diseases characterized by increased IgE production, IL-5 was elevated in all patients with increased numbers of eosinophils. The close correlation between IL-5 levels, number of eosinophils, and activated T cells further supports a role for IL-5 in causing tissue eosinophilia.

[Planimetric quantification of aortic valve stenoses using multiplanar transesophageal echocardiography]

Standard techniques used in order to quantify the severity of aortic valve stenoses in clinical practice comprise: transthoracic echocardiography, namely, by determining maximum and mean transvalvular gradients and evaluating aortic valve areas, as well as invasive techniques which quantify aortic valve areas through hemodynamic pressure measurements and application of the Gorlin formula. Since the introduction of the multiplane TEE technique, it has become feasible to scan the aortic valve in a strictly horizontal plane and quantify the aortic valve orifice by planimetry. In this study, we investigated 23 patients with various degrees of aortic valve stenoses. We compared aortic valve areas, which had been planimetrically determined by multiplane TEE scans, and mean aortic valve gradients (standard TEE technique) with pressure gradients and valve areas derived from hemodynamic measurements obtained during cardiac catheterization, and have found that the valve areas as well as the mean pressure gradients correlate well.

Enoximone therapy as pharmacological bridging to cardiac transplantation

Keeping pre-transplant patients alive while waiting for a suitable donor is still a major challenge. New pharmacological agents which can provide improved hemodynamics are urgently needed in patients with severe heart failure who are on the waiting list for cardiac transplantation. Intravenous enoximone therapy (an initial 0.5 mg/kg bolus, then 1.25-5.0 mcg/kg/min infusion) was administered to 35 transplant candidates with progressive heart failure despite optimal drug regimen including digoxin, diuretics, and ACE-inhibitors. In 18 out of 35 patients complete hemodynamic, echocardiographic, neurohumoral, and Holter-ECG studies were performed before and 24 hours after intravenous enoximone infusion. Patients were then continued on chronic oral therapy of 100 mg twice a day. Enoximone infusion increased the cardiac index (CI) (1.78 +/- 0.45 l/min/m2 vs 3.04 +/- 0.83 l/min/m2; p < 0.001) and stroke volume index (SVI)(22.33 +/- 9.45 ml/m2 vs 32.28 +/- 7.29 ml/m2; p < 0.05) and decreased wedge pressure (PCP)(24.1 +/- 11.98 mmHg vs 17.78 +/- 8.76 mmHg; p < 0.05) while mean arterial pressure (MAP) was unchanged. Left ventricular ejection time (LVET)(225.1 +/- 26.9 ms vs 242.2 +/- 25.8 ms; p < 0.05) was increased whereas other echocardiographic parameters were unchanged (Left ventricular end-diastolic dimension LVEDD, left ventricular end-systolic dimension LVESD, fractional shortening FS, early diastolic relaxation parameter Te). Plasma neurohumoral parameters did not change (Aldosterone, epinephrine, renin, atrial natriuretic factor) except for a significant drop in norepinephrine (936.7 +/- 443.2 pg/ml vs 522.4 +/- 287.6 pg/ml; p < 0.05). Holter-ECG parameters (ventricular premature beats VPB, couplets, ventricular tachycardia VT) were not influenced by enoximone infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Atopic dermatitis: correlation of peripheral blood T cell activation, eosinophilia and serum factors with clinical severity

In the first part of this study peripheral blood lymphocyte subpopulations, their activation state and various serum parameters were measured in extrinsic and intrinsic atopic dermatitis (AD) patients compared to normal individuals. Beside the characteristic eosinophilia, significantly increased numbers of CD4+ T cells with increased expression of IL-2 receptors (IL-2R) and HLA-DR were noted in the AD patients. In addition, extrinsic AD patients showed increased numbers of CD23+ B cells and decreased numbers of CD16+ natural killer cells. Moreover, increased serum levels of eosinophil cationic protein (ECP) and soluble IL-2R as well as soluble factors that prolong survival of eosinophils in vitro could be demonstrated. In the second section of this study we determine how these blood immunological parameters relate to the clinical severity of the skin lesions of AD, by weekly analysis of 12 AD patients attending a high altitude clinic for 3 to 6 weeks. The patients were divided into two groups on the basis of treatment with topical steroids, but during the observation period a significant improvement in clinical status was observed in all AD patients independent of topical steroid therapy. A progressive decrease in eosinophil and activated T cell numbers, soluble IL-2R levels and serum eosinophil survival prolonging activity could be demonstrated, which closely correlated with the clinical severity of the AD.

Measuring the determinants of work values for psychiatrists' services in the resource-based relative value scale study

OBJECTIVE

As part of the Harvard resource-based relative value scale study, the authors investigated how well the codes in the Physician's Current Procedural Terminology, 4th edition, or CPT-4, match psychiatric services to the work involved in evaluating and managing patients and how patient care characteristics affect different levels of psychiatric work.

METHOD

A random sample of over 200 psychiatrists and subspecialists was asked to use 68 typical clinical examples or vignettes to evaluate services described by CPT codes. Data were analyzed by multivariate statistical methods.

RESULTS

The survey showed that the existing coding system does not adequately describe the work that psychiatrists do. Within a single code (e.g., 90844, individual medical psychotherapy), there was wide (more than twofold) variation in the estimates, from multiple measurements based on different vignettes, of the amount of work represented. Estimates of work values varied significantly according to treatment setting and patient characteristics: psychiatric services in the hospital showed an average work value 25% greater than that for office services; treating new patients involved 18% more effort than treating established patients; and treating patients described as at risk of harming self or others increased the psychiatrists' work effort by 36%.

CONCLUSIONS

Revisions in coding evaluation and management services in the new Medicare fee schedule for psychiatric services should be further refined and then implemented. These revisions would bring the coding system into line with psychiatric practice, making it a better way of accounting for the relative work involved in treating patients of varying difficulty.

Results and impacts of the Resource-Based Relative Value Scale

On January 1, 1992, the Health Care Financing Administration implemented the 1989 legislation reforming the Medicare payment system for physicians' services. The cornerstone of the new payment reform is the Medicare Fee Schedule (MFS), which is based on the Resource-Based Relative Value Scale (RBRVS). In this article, the major findings of the RBRVS study and its impacts on physician payment are summarized. The authors report the impacts of a RBRVS-based fee schedule on Medicare fees and physicians' income if it were fully implemented, assuming budget neutrality and absence of volume changes in services. Under this scenario, fees for evaluation and management services increase by 15% to 45%, while fees for invasive services and diagnostic tests decrease by 20% to 30%. These changes increase the Medicare income of family practitioners by more than 30% while decreasing the income of most surgical specialties by 10% to 20%.

An overview of the development and refinement of the Resource-Based Relative Value Scale. The foundation for reform of U.S. physician payment

Responding to distortions in payment rates between services, policymakers in the United States have sought a systematic and rational foundation for determining physician fees. One such approach to paying physicians, the Resource-Based Relative Value Scale (RBRVS), determines fees by measuring the relative resource costs required to produce them. On January 1, 1992, the Medicare program implemented a new payment system for physician services based on the RBRVS. This article provides a brief history of the RBRVS and a summary of the methods and data used to derive it. This overview represents the culmination of 6 years of research by the Harvard RBRVS study team and provides a road map to the study's concepts and definitions. The overview also provides a context for the articles in this issue that describe five major studies undertaken since 1988. The study's overall results are presented in the last article of the series.

Predicting the work of evaluation and management services

Physicians, carefully adhering to the definitions of Physicians' Current Procedural Terminology (CPT) billing codes, used the same CPT codes to denote evaluation and management services that varied widely in work and used different codes for services whose work was the same. As payment shifted to the Medicare Fee Schedule, it was important that the coding system be redefined so that codes consistently reflect the resource costs of these services. Redefining these codes for a resource-based payment system required an understanding of how verifiable predictors relate to physician work. Using data obtained from the Resource-Based Relative Value Scale (RBRVS) study regarding 377 services surveyed among physicians in 31 specialties, multiple regression analyses of the relationship of different variables to the mean values of work were performed. Intraservice time, which accounted for 90% of the variance, was the most important predictor of intraservice work. Specification of time, which previously had not been an element in the definitions of CPT codes for evaluation and management services, was useful in refining these codes so that their value corresponds more closely to resource costs. Other predictors of work were site of service or visit type, patient status (new/initial, established/subsequent), and referral status (consultation, nonconsultation).

Ischemia: reperfusion injury and restenosis after coronary angioplasty

Percutaneous transluminal coronary angioplasty (PTCA) is a very effective technology that allows, without surgery, successful mechanical revascularization of acutely or chronically obstructed coronary arteries. The success of PTCA in patients with acute myocardial infarction or unstable angina is questioned by early coronary reocclusion and by so-called reperfusion injury. In a biochemical context, reperfusion injury occurs as a very complex interaction between the different tissues that build heart muscle. Free radicals play a pivotal role and initiate a deleterious cascade of events after reperfusion. Protective mechanisms such as superoxide dismutase, glutathione peroxidase, and catalase are normally present in the cell to prevent damage by free radicals. Endothelial cells have a greater number of specific physiologic and metabolic functions and influence the microcirculatory flow. In the presence of exogenous glucose, coronary endothelial cells show a pronounced lactate production under well-oxygenated conditions. Low energy demand and high glycolytic activity may be the cause of why the coronary endothelium is less severely injured than the cardiomyocytes in the ischemic and anoxic heart. The success of PTCA in patients with chronically obstructed coronary arteries (stable angina) is questioned by vessel occlusion and restenosis. Restenosis is a very complex process involving clinical, morphological, procedural, regional flow-dependent, and biological determinants. Early platelet deposition, formation of mural thrombus, coronary vasospasm, and elastic recoil forces of stretched vessel wall may contribute to early restenosis in the first days after PTCA, but the peak incidence of restenosis occurs between two and three months after PTCA. Intimal hyperplasia or proliferation of smooth muscle cells is believed to be the fundamental process of restenosis. To solve the problem of restenosis, much effort has been expended, which includes several technical and pharmacological approaches. Pharmacological strategies, systemically or locally administered, aim at increased vasomotor tone, platelet function, smooth muscle cell proliferation/migration, and fibrocollagenous healing. Up to now none of the proposed drugs has been able to reduce the restenosis rate. There is experimental evidence for a claim that the antioxidant functions of vitamins (E, C, and beta-carotene) may prevent restenosis post-PTCA. Until recently, in most post-PTCA restenosis trials the angiographic analyses were not performed using computerized measurement methods. In order to assess the efficacy of acute or long-term interventions on the natural course or acute complications of coronary artery disease, quantitative measures have been introduced and validated that make use of digital coronary angiography and computerized image processing techniques.(ABSTRACT TRUNCATED AT 400 WORDS)