Humoral immunity against SARS-CoV-2 evoked by heterologous vaccination groups using the CoronaVac (Sinovac) and BNT162b2 (Pfizer/BioNTech) vaccines in Chile

Introduction

Severe acute respiratory syndrome virus 2 (SARS-CoV-2) has caused over million deaths worldwide, with more than 61,000 deaths in Chile. The Chilean government has implemented a vaccination program against SARS-CoV-2, with over 17.7 million people receiving a complete vaccination scheme. The final target is 18 million individuals. The most common vaccines used in Chile are CoronaVac (Sinovac) and BNT162b2 (Pfizer-Biotech). Given the global need for vaccine boosters to combat the impact of emerging virus variants, studying the immune response to SARS-CoV-2 is crucial. In this study, we characterize the humoral immune response in inoculated volunteers from Chile who received vaccination schemes consisting of two doses of CoronaVac [CoronaVac (2x)], two doses of CoronaVac plus one dose of BNT162b2 [CoronaVac (2x) + BNT162b2 (1x)], and three doses of BNT162b2 [BNT162b2 (3x)].

Methods

We recruited 469 participants from Clínica Dávila in Santiago and the Health Center Víctor Manuel Fernández in the city of Concepción, Chile. Additionally, we included participants who had recovered from COVID-19 but were not vaccinated (RCN). We analyzed antibodies, including anti-N, anti-S1-RBD, and neutralizing antibodies against SARS-CoV-2.

Results

We found that antibodies against the SARS-CoV-2 nucleoprotein were significantly higher in the CoronaVac (2x) and RCN groups compared to the CoronaVac (2x) + BNT162b2 (1x) or BNT162b2 (3x) groups. However, the CoronaVac (2x) + BNT162b2 (1x) and BNT162b2 (3x) groups exhibited a higher concentration of S1-RBD antibodies than the CoronaVac (2x) group and RCN group. There were no significant differences in S1-RBD antibody titers between the CoronaVac (2x) + BNT162b2 (1x) and BNT162b2 (3x) groups. Finally, the group immunized with BNT162b2 (3x) had higher levels of neutralizing antibodies compared to the RCN group, as well as the CoronaVac (2x) and CoronaVac (2x) + BNT162b2 (1x) groups.

Discussion

These findings suggest that vaccination induces the secretion of antibodies against SARS-CoV-2, and a booster dose of BNT162b2 is necessary to generate a protective immune response. In the current state of the pandemic, these data support the Ministry of Health of the Government of Chile's decision to promote heterologous vaccination as they indicate that a significant portion of the Chilean population has neutralizing antibodies against SARS-CoV-2.

Geographical Distribution of Genetic Variants and Lineages of SARS-CoV-2 in Chile

The pandemic caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a worldwide public health concern. First confined in China and then disseminated widely across Europe and America, SARS-CoV-2 has impacted and moved the scientific community around the world to working in a fast and coordinated way to collect all possible information about this virus and generate new strategies and protocols to try to stop the infection. During March 2020, more than 16,000 full viral genomes have been shared in public databases that allow the construction of genetic landscapes for tracking and monitoring the viral advances over time and study the genomic variations present in geographic regions. In this work, we present the occurrence of genetic variants and lineages of SARS-CoV-2 in Chile during March to April 2020. Complete genome analysis of 141 viral samples from different regions of Chile revealed a predominance of variant D614G like in Europe and the USA and the major presence of lineage B.1. These findings could help take control measures due to the similarity of the viral variants present in Chile, compared with other countries, and monitor the dynamic change of virus variants in the country.

Phylogenetic analysis of the first four SARS-CoV-2 cases in Chile

The current pandemic caused by the new coronavirus is a worldwide public health concern. To aboard this emergency, and like never before, scientific groups around the world have been working in a fast and coordinated way to get the maximum of information about this virus when it has been almost 3 months since the first cases were detected in Wuhan province in China. The complete genome sequences of around 450 isolates are available, and studies about similarities and differences among them and with the close related viruses that caused similar epidemics in this century. In this work, we studied the complete genome of the first four cases of the new coronavirus disease in Chile, from patients who traveled to Europe and Southeast Asia. Our findings reveal at least two different viral variants entries to Chilean territory, coming from Europe and Asia. We also sub‐classified the isolates into variants according to punctual mutations in the genome. Our work contributes to global information about transmission dynamics and the importance to take control measures to stop the spread of the infection.

First genetic study of the SARS‐CoV‐2 isolates in Chile.

At least two different viral variants were identified from Chilean travelers.

S and G Chilean variants are associated to European and Asian viral isolates.

[Genetic characterization of Listeria monocytogenes strains isolated during 2007-2014 in Chile]

BACKGROUND

Listeria monocytogenes is a foodborne pathogen that causes listeriosis, a disease that can present as febrile gastroenteritis or as an invasive form that has high mortality rates. So far, the genetic diversity of strains of L. monocytogenes isolated from patients, foods and environmental sources in Chile has been poorly studied.

AIM

To characterize genetically L. monocytogenes strains received by the Institute of Public Health of Chile (ISP) between 2007 and 2014.

METHODS

We selected 94 strains of L. monocytogenes corresponding to 94 different pulsotypes identified by pulsed field gel electrophoresis (PFGE), DNA was extracted and serotyping was performed by polymerase chain reaction (PCR) and multilocus sequence typing (MLST).

RESULTS

The most common serotype was 4b (55.3%), followed by serotypes 1/2a (25.5%), 1/2b (17%) and 1/2c (2.2%). 32 sequence-type (ST) were identified, of which 4 were new, and the predominant ones were ST1 (28.7%) and ST2 (13.8%). All the strains of L. monocytogenes were grouped in Lineages I and II.

CONCLUSIONS

A great genetic variability was observed in the strains of L. monocytogenes analyzed, being predominant the ST1 and ST2, both belonging to Lineage I. Our results contribute to know the population structure of this pathogen in Chile and its presence in clinical samples, food and the environment.

Genetic variability of human papillomavirus type 66 L1 gene among women presenting for cervical cancer screening in Chile

The high-risk human papillomaviruses (HR-HPVs) are involved in the development of cervical cancer. Nevertheless, there are differences in the oncogenic potential among them. HPV-16 and HPV-18 are associated with approximately 70% of cancer worldwide, and both types are the most extensively studied HR-HPV. Great variations in the prevalence of HR-HPV have been described in different countries. The impact of these variations on the epidemiology of lesions and cervical cancer is currently unknown. A high prevalence of HPV-66 has been detected in Chile. Here, we have analyzed the genetic variability of the L1 gene from HPV-66-infected Chilean women. Higher order interactions between identified mutations were analyzed by co-variation and cluster analyses. Antigenic-index alterations following L1 mutations and B-cell epitopes were predicted by BcePred algorithm. HPV-66 L1 sequences clustered phylogenetically into two main clades. The genetic variability in the HPV-66 L1 gene involved thirty nucleotide changes. Four of these were for the first time identified in this study. Some of these variants are embedded in the B-cell epitope regions. Amino acid homology in the immunodominant epitopes of HPV-66 L1 protein (DE, FG and H1 loops) was 42.9-59.1% and 28.6-68.9% compared with HPV-16 and HPV-18, respectively. The results of this research suggest that the neutralizing epitopes of HPV-66 are antigenically different compared to HPV-16 and HPV-18. Our findings show the need to perform new structural and immunological studies on HPV-66 L1 protein to evaluate the cross-protection conferred by current HPV vaccines.

Excess Lead-210 and Plutonium-239+240: Two suitable radiogenic soil erosion tracers for mountain grassland sites

The expected growing population and challenges associated with globalisation will increase local food and feed demands and enhance the pressure on local and regional upland soil resources. In light of these potential future developments it is necessary to define sustainable land use and tolerable soil loss rates with methods applicable and adapted to mountainous areas. Fallout-radionuclides (FRNs) are proven techniques to increase our knowledge about the status and resilience of agro-ecosystems. However, the use of the Caesium-137 (¹³⁷Cs) method is complicated in the European Alps due to its heterogeneous input and the timing of the Chernobyl fallout, which occurred during a few single rain events on partly snow covered ground. Other radioisotopic techniques have been proposed to overcome these limitations. The objective of this study is to evaluate the suitability of excess Lead-210 (²¹⁰Pb_ex) and Plutonium-239+240 (^239+240Pu) as soil erosion tracers for three different grassland management types at the steep slopes (slope angles between 35 and 38°) located in the Central Swiss Alps. All three FRNs identified pastures as having the highest mean (± standard deviation) net soil loss of -6.7 ± 1.1, -9.8 ± 6.8 and -7.0 ± 5.2 Mg ha^-1 yr^-1 for ¹³⁷Cs, ²¹⁰Pb_ex and ^239+240Pu, respectively. A mean soil loss of -5.7 ± 1.5, -5.2 ± 1.5 and-5.6 ± 2.1 was assessed for hayfields and the lowest rates were established for pastures with dwarf-shrubs (-5.2 ± 2.5, -4.5 ± 2.5 and -3.3 ± 2.4 Mg ha^-1 yr^-1 for ¹³⁷Cs, ²¹⁰Pb_ex and ^239+240Pu, respectively). These rates, evaluated at sites with an elevated soil erosion risk exceed the respective soil production rates. Among the three FRN methods used, ^239+240Pu appears as the most promising tracer in terms of measurement uncertainty and reduced small scale variability (CV of 13%). Despite a higher level of uncertainty, ²¹⁰Pb_ex produced comparable results, with a wide range of erosion rates sensitive to changes in grassland management. ²¹⁰Pb_ex can then be as well considered as a suitable soil tracer to investigate alpine agroecosystems.

Overview of the impact of Typhoid and Paratyphoid fever. Utility of Ty21a vaccine (Vivotif®)

Cases of diarrhoeal disease number from 1.7 to 5 billion per year worldwide. One of the main causes of diarrhoeal disease is typhoid fever, which is a potentially life-threatening multi-systemic illness. According to the most recent estimates, a total of 26.9 million typhoid fever episodes occurred in 2010. The geographical distribution of the disease differs widely; in developed countries, the incidence rate per 100,000 per year varies from < 0.1 to 0.3, and the disease mainly affects people who travel to endemic areas located in low- and middle-income countries. Low- and middle-income countries are mainly affected owing to the lack of clean water and proper sanitation. In the fight against this plague, prevention is fundamental, and vaccination against typhoid is an effective measure. Vivotif^® is an oral live attenuated vaccine which contains a mutated strain of Salmonella (Ty21a) and reproduces the natural infection. The vaccine was first licensed in Europe in 1983 and in the US in 1989, and over the years it has proved efficacious and safe. It is indicated for adults and children from 5 years of age upwards. Specifically, in the most developed countries, vaccination is suggested for highrisk population groups and particularly for international travellers to destinations where the risk of contracting typhoid fever is high. It must also be borne in mind that international travel is increasing. Indeed, international tourist arrivals totalled 1,184 million in 2015 and, on the basis of current trends, international travel is expected to grow by 3-4% in 2017. Vivotif^® appears to be a powerful means of disease prevention, the importance of which is highlighted by the spread of antibiotic-resistant strains of Salmonella typhy (S. typhi).

Analysis of Mycobacterium tuberculosis Genotypic Lineage Distribution in Chile and Neighboring Countries

Tuberculosis (TB), caused by the pathogen Mycobacterium tuberculosis (MTB), remains a disease of high importance to global public health. Studies into the population structure of MTB have become vital to monitoring possible outbreaks and also to develop strategies regarding disease control. Although Chile has a low incidence of MTB, the current rates of migration have the potential to change this scenario. We collected and analyzed a total of 458 M. tuberculosis isolates (1 isolate per patient) originating from all 15 regions of Chile. The isolates were genotyped using the spoligotyping method and the data obtained were analyzed and compared with the SITVIT2 database. A total of 169 different patterns were identified, of which, 119 patterns (408 strains) corresponded to Spoligotype International Types (SITs) and 50 patterns corresponded to orphan strains. The most abundantly represented SITs/lineages were: SIT53/T1 (11.57%), SIT33/LAM3 (9.6%), SIT42/LAM9 (9.39%), SIT50/H3 (5.9%), SIT37/T3 (5%); analysis of the spoligotyping minimum spanning tree as well as spoligoforest were suggestive of a recent expansion of SIT42, SIT50 and SIT37; all of which potentially evolved from SIT53. The most abundantly represented lineages were LAM (40.6%), T (34.1%) and Haarlem (13.5%). LAM was more prevalent in the Santiago (43.6%) and Concepción (44.1%) isolates, rather than the Iquique (29.4%) strains. The proportion of X lineage was appreciably higher in Iquique and Concepción (11.7% in both) as compared to Santiago (1.6%). Global analysis of MTB lineage distribution in Chile versus neighboring countries showed that evolutionary recent lineages (LAM, T and Haarlem) accounted together for 88.2% of isolates in Chile, a pattern which mirrored MTB lineage distribution in neighboring countries (n = 7378 isolates recorded in SITVIT2 database for Peru, Brazil, Paraguay, and Argentina; and published studies), highlighting epidemiological advantage of Euro-American lineages in this region. Finally, we also observed exclusive emergence of patterns SIT4014/X1 and SIT4015 (unknown lineage signature) that have hitherto been found exclusively in Chile, indicating that conditions specific to Chile, along with the unique genetic makeup of the Chilean population, might have allowed for a possible co-evolution leading to the success of these emerging genotypes.

Nuclear Functions of Nucleolin through Global Proteomics and Interactomic Approaches

Nucleolin (NCL) is a major component of the cell nucleolus, which has the ability to rapidly shuttle to several other cells' compartments. NCL plays important roles in a variety of essential functions, among which are ribosome biogenesis, gene expression, and cell growth. However, the precise mechanisms underlying NCL functions are still unclear. Our study aimed to provide new information on NCL functions via the identification of its nuclear interacting partners. Using an interactomics approach, we identified 140 proteins co-purified with NCL, among which 100 of them were specifically found to be associated with NCL after RNase digestion. The functional classification of these proteins confirmed the prominent role of NCL in ribosome biogenesis and additionally revealed the possible involvement of nuclear NCL in several pre-mRNA processing pathways through its interaction with RNA helicases and proteins participating in pre-mRNA splicing, transport, or stability. NCL knockdown experiments revealed that NCL regulates the localization of EXOSC10 and the amount of ZC3HAV1, two components of the RNA exosome, further suggesting its involvement in the control of mRNA stability. Altogether, this study describes the first nuclear interactome of human NCL and provides the basis for further understanding the mechanisms underlying the essential functions of this nucleolar protein.

Nucleolin interacts with US11 protein of herpes simplex virus 1 and is involved in its trafficking

Herpes simplex virus type 1 (HSV-1) infection induces profound nucleolar modifications at the functional and organizational levels, including nucleolar invasion by several viral proteins. One of these proteins is US11, which exhibits several different functions and displays both cytoplasmic localization and clear nucleolar localization very similar to that of the major multifunctional nucleolar protein nucleolin. To determine whether US11 interacts with nucleolin, we purified US11 protein partners by coimmunoprecipitations using a tagged protein, Flag-US11. From extracts of cells expressing Flag-US11 protein, we copurified a protein of about 100 kDa that was further identified as nucleolin. In vitro studies have demonstrated that nucleolin interacts with US11 and that the C-terminal domain of US11, which is required for US11 nucleolar accumulation, is sufficient for interaction with nucleolin. This association was confirmed in HSV-1-infected cells. We found an increase in the nucleolar accumulation of US11 in nucleolin-depleted cells, thereby revealing that nucleolin could play a role in US11 nucleocytoplasmic trafficking through one-way directional transport out of the nucleolus. Since nucleolin is required for HSV-1 nuclear egress, the interaction of US11 with nucleolin may participate in the outcome of infection.

Knowledge-based 3D analysis from 2D medical images

An anatomical knowledge-based system for image analysis that interprets CT/MR (computed tomography/magnetic resonance) images of the human chest cavity is reported. The approach utilizes a low-level image analysis system with the ability to analyze the data in bottom-up (or data-driven) and top-down (or model-driven) modes to improve the high-level recognition process. Several image segmentation algorithms, including K-means clustering, pyramid-based region extraction, and rule-based merging, are used for obtaining the segmented regions. To obtain a reasonable number of well-segmented regions that have a good correlation with the anatomy, a priori knowledge in the form of masks is used to guide the segmentation process. Segmentation of the brain is also considered.

Polymorphisms in genes involved in folate metabolism as risk factors for NTDs

Moderate hyperhomocysteinemia in pregnant women has been associated with an increased risk of neural tube defects (NTDs). Periconceptional supplementation with multi-vitamins containing folic acid may normalize homocysteine metabolism and decrease the NTD risk. The C677 T variant of the MTHFR gene coding for a thermolabile enzyme has been described as the first genetic risk factor that accounts for a group of NTDs characterized by low maternal folate status and high homocysteine concentrations. Another common mutation of the same MTHFR gene, A1298 C, has also been described as an NTD risk factor. In addition to abnormal folate metabolism, anything that compromises the internalization of folate into the cell may be involved in the pathogenesis of NTDs. For this reason, a common polymorphism in the RFC-1 gene encoding the reduced folate carrier protein (A80 G) could also be an additional NTD risk factor. In the present study we examined the genotypic distributions and the allele frequencies of MTHFR A1298 C and RFC-1 A80 G polymorphisms in DNA samples from healthy Italian individuals and compared them to the frequencies observed in NTD cases and their parents. By means of restriction enzymatic analysis, we determined that the frequency of the mutated C allele of the A1298 C mutation was 0.25 among control individuals, which is in the range of that recently reported in other ethnic groups. However, we report that the mutant C allele frequencies are significantly higher among NTD cases and case mothers than among controls (0.39, 0.44, 0.25). Furthermore, for the RFC-1 A80 G mutation, we found that the frequency of the G allele of the RFC-1 mutation was 0.46 in the control population, suggesting that this is a common polymorphism in the Italian population. In spite of the high prevalence of the 80 G/G genotype among healthy subjects, we observed an increased frequency of the G allele in NTD-affected children, and their mothers and fathers. These preliminary results indicate that both the MTHFR and RFC-1 polymorphisms may play a role in NTD risk, at least in the Italian population. Further studies should be directed toward the evaluation of the level of risk conferred by the mutant MTHFR and RFC-1 genotypes, as well as the interaction between these genetic determinants and other nutritional and environmental factors.

Lysyl oxidase activates the transcription activity of human collagene III promoter. Possible involvement of Ku antigen

Lysyl oxidase is an extracellular enzyme that controls the maturation of collagen and elastin. Lysyl oxidase and collagen III often show similar expression patterns in fibrotic tissues. Therefore, we investigated the influence of lysyl oxidase overexpression on the promoter activity of human COL3A1 gene. Our results showed that when COS-7 cells overexpressed the mature form of lysyl oxidase, the activity of the human COL3A1 promoter was increased up to an average of 12 times when tested by luciferase reporter assay. The effect was specific, because other promoters were not affected. Moreover, lysyl oxidase effect was abolished by beta-aminopropionitrile, a specific inhibitor of its catalytic activity. Electrophoretic mobility shift assay showed a binding activity in the region from -101 to -77 that was significantly increased by lysyl oxidase overexpression. The binding was specifically competed by the cold probe, and the mutagenesis of this region abolished both the binding activity in gel retardation and lysyl oxidase stimulation of COL3A1 promoter in transfection experiments. We identified the binding activity as Ku antigen in its two components: Ku80 and Ku70. This study suggests a new coordinated mechanism by which lysyl oxidase might control the development of fibrosis.

[Concerning Empedocles' Fragment 100 D.-K]

Concerning a fragment by Empedocles on respiration.

Segmentation of medical images through competitive learning

In image analysis applications, segmentation of gray-level images into meaningful regions is an important low-level processing step. Various approaches to segmentation investigated in the literature, in general, use either local information of gray-level values of pixels (region growing based methods, for example) or the global information (histogram thresholding based methods, for example). Application of these approaches for segmenting medical images often does not provide satisfactory results. Medical images are usually characterized by low local contrast and noisy or faded features causing unacceptable performance of local information based segmentation methods. In addition, because of a large amount of structural information found in medical images, global information based segmentation methods yield inadequate results in region extraction. We present a novel approach to image segmentation that combines local contrast as well as global gray-level distribution information. The presented method adaptively learns useful features and regions through the use of a normalized contrast function as a measure of local information and a competitive learning based method to update region segmentation incorporating global information about the gray-level distribution of the image. In this paper, we present the framework of such a self organizing feature map, and show the results on simulated as well as real medical images.

Silent ischemia in unstable angina is related to an altered cardiac norepinephrine handling

BACKGROUND

Inferential evidence suggests that silent ischemia might be related to sympathetic activity. Study of [3H]norepinephrine kinetics is a suitable tool to assess the regional sympathetic activity. This method was applied to investigate whether silent myocardial ischemia in unstable angina is related to and depends on cardiac sympathetic overactivity.

METHODS AND RESULTS

Patients with active unstable angina were compared with patients with inactive unstable angina, stable effort angina, and controls. Silent myocardial ischemia was evaluated by three 24-hour Holter monitoring periods on alternate days, and [3H]norepinephrine kinetics was assessed under rest conditions and following the cold pressor test. Simultaneously, catecholamine concentrations were measured in the aortic, coronary sinus, and peripheral venous blood. Different than the other groups (p = 0.0013), in patients with active unstable angina, the majority of silent ischemic episodes occurred without increase in heart rate. These patients had a positive coronary sinus-aorta norepinephrine gradient, both at rest and following the cold pressor test. [3H]Norepinephrine kinetics demonstrated an increased selective cardiac spillover, both at rest and, even more, after the cold pressor test. Reduced cardiac [3H]norepinephrine extraction also was found. A significant relation was found between the number of ischemic episodes or the overall duration of silent ischemia and norepinephrine spillover, both at rest and following cold application.

CONCLUSIONS

During the acute phase of unstable angina (but not in the quiescent phase or in stable effort angina), a disorder in cardiac norepinephrine handling occurs. This results in a reflex cardiac sympathetic overactivity that plays a major role in the occurrence of silent myocardial ischemia.

Knowledge-based multi-modality three-dimensional image analysis of the brain

With the recent advances in medical imaging, three-dimensional anatomical and metabolic images of the brain are now available through MR/CT and PET/SPECT imaging modalities. Computerized multi-modality three-dimensional brain image registration and analysis can provide important correlated information for improving diagnosis and studying the pathology of disease. Such analysis may also provide help in planning brain surgery. Further, an anatomical model based quantification and analysis of internal structure can be used to develop a computerized anatomical atlas. Conventional anatomical atlases provide rigid spatial distribution of internal structures extracted from a single subject. The proposed computerized anatomical atlas provides probabilistic spatial distributions which can be easily updated to incorporate the variability of brain structures of subjects selected from pre-defined groups. This paper first presents a review of the current trends in knowledge-based segmentation, labeling, and analysis of MR brain images and then describes the Principal Axes Transformation based registration of three-dimensional MR brain images to develop composite models of selected internal brain structures. The composite models can be used as a computerized anatomical atlas in model-based segmentation and labeling of MR brain images. Three-dimensional labeled MR images of the brain can also be registered and correlated with PET images for analyzing the metabolic activity in the anatomically selected volume of interest. On the other hand, a volume of interest can be selected using the metabolic information and then analyzed for correlated anatomical information using the registered MR-PET images.

[Early isovolumetric relaxation: correlation with the densitometric analysis of coronary stenosis]

Early relaxation is characterized by a segmental outward wall movement during isovolumic relaxation. There is still no general agreement as to its significance. Some Authors have considered the phenomenon to be a specific marker of isolated coronary narrowing, others have regarded it as a normal variation of left ventricular relaxation and still others concluded that it is a compensatory phenomenon to local ischemia in another region. We used a method of quantitative assessment of regional left ventricular function and a videodensitometric analysis of coronary stenosis. In our study we didn't observe an improved systolic function of the regions that presented early relaxation, but a slight non significant reduction. We did neither observe any correlation between early relaxation and ischemia provoked by stress test nor between early relaxation and coronary artery disease. The amplitude of early relaxation was not statistically different between patients with and without stenosis of left anterior descending artery. We conclude that early relaxation is a normal variation of left ventricular relaxation.

Assessment of severity of coronary narrowings by quantitative exercise echocardiography and comparison with quantitative arteriography

To determine the correlation of quantitative assessment of coronary narrowings with left ventricular functional impairment induced by exercise, 57 patients with 1-vessel coronary artery disease and without evidence of collateral flow were studied. A significant relation was observed between minimal cross-sectional area, percent area stenosis, minimal lumen diameter, percent diameter stenosis and the percentage of segmental area change from rest to peak exercise in a vascular distribution territory (r = 0.76, p less than 0.001; r = -0.55, p less than 0.001; r = 0.56, p less than 0.001; r = -0.75, p less than 0.001, respectively). For minimal cross-sectional area, the best cut-off value to separate significantly patients who had a decrease in contractility at peak exercise testing from those who had a normal response was 2 mm2 (p less than 0.001); for percent cross-sectional area stenosis, it was 75% (p less than 0.001); for minimal lumen diameter, it was 0.7 mm (p less than 0.001); and, for percent diameter stenosis, it was 85% (p less than 0.001). High cut-off values for angiographic variables are necessary to separate significantly patients who have a decrease in contractility at peak exercise testing from those who have a normal response. Several patients with mild coronary stenoses may have either normal or abnormal wall motion during exercise. Thus, exercise echocardiography is a useful tool in detecting the presence of fairly severe anatomic narrowing, whereas it is of limited clinical use in the assessment of intermediate coronary atherosclerotic lesions.

[Effect of changes of the left ventricular diastolic pressure on the coronary circulation hemodynamics]

In order to understand the effect of LVEDP changes caused by contrast injection during angiography on coronary hemodynamics we studied 15 patients (5 congestive CMP, 5 mixed angina and 5 controls). Our results do not cope with an important negative role played from LVEDP changes on coronary hemodynamics and cardiac metabolism. Actually LVEDP increase after ventriculography was balanced by coronary flow increase and impedance reduction even when the latter has been matched with LVEDP. We also observed lactate metabolism changes which are not likely to be provoked by myocardial ischemia, since there was not a definite negativization of % lactate extraction and delta A-VO2 always turned to reduction; this is apparently not in agreement with other Authors who had reported metabolic alterations suggestive for myocardial ischemia, even if they did not calculate delta A-VO2 and coronary flow. This difference could be related to the different populations studied, specially when considering the different functional meaning of coronary stenoses of the same degree at angiography. Is thus the Authors' thought that, when coronary reserve is still adequate, is it possible not to take into account LVEDP, which becomes important in patients with a more advanced coronary disease as in those cases this extravascular impedance factor to coronary flow could take his own worsening role.

Defective coronary prostaglandin modulation in anginal patients

In order to investigate whether coronary vasodilating prostaglandins (PGI2 and PGE2) have a role in the pathophysiology of myocardial ischemia, 26 patients with angina pectoris and 23 control subjects (nonischemic patients) were studied by assessing coronary hemodynamics and prostaglandin formation in relation to sympathetic stimulation. Following a cold pressor test (CPT), coronary prostaglandin output markedly increased (p less than 0.001) and coronary vascular resistance (CVR) decreased (p less than 0.001) in all control subjects. In contrast, in anginal patients prostaglandins in the coronary sinus were undetectable and after CPT prostaglandin output did not increase, whereas CVR paradoxically increased (p less than 0.001). In control subjects the inhibition of coronary prostaglandin formation (by ketoprofen [1 mg/kg intravenously] or by aspirin [15 mg/kg intravenously]) caused a paradoxical increase of CVR following CPT (p less than 0.001). In anginal patients the inhibition of prostaglandins further exaggerated the increase of CVR after CPT (p less than 0.001). These results indicate that coronary vasodilating prostaglandin PGI2 and PGE2 play a role in modulating coronary vascular response to sympathetic stimulation induced by CPT. Their defective production in anginal patients may be responsible for the paradoxical increase in CVR following sympathetic stimulation.

Usefulness of the dipyridamole-Doppler test for diagnosis of coronary artery disease

Two-dimensional and Doppler echocardiographic studies and a hemodynamic investigation were performed during dipyridamole testing in 42 subjects (13 control subjects and 29 patients with coronary artery disease [CAD]), to evaluate the ability of dipyridamole Doppler echocardiography in identifying patients with ischemic left ventricular dysfunction. In the control group, after dipyridamole infusion, Doppler-derived parameters increased significantly from baseline (p less than 0.001). In patients with CAD, peak flow velocity, flow velocity integral and stroke volume failed to increase after dipyridamole infusion (0.89 +/- 0.21 to 0.85 +/- 0.18 m/s, difference not significant; 14 +/- 3 to 12 +/- 4 cm, difference not significant, and 56 +/- 13 to 50 +/- 14 ml/beat, p less than 0.05, respectively). Heart rate, rate pressure product, systemic vascular resistance and mean right atrial pressure had similar variations in the 2 groups. Changes in the 3 Doppler-derived parameters are closely related to the variations of peak positive dP/dt, stroke volume (thermodilution) and left ventricular end-diastolic pressure and are closely related to the coronary angiography jeopardy score and to the appearance of wall motion abnormalities. Thus, by combining Doppler and 2-dimensional echocardiography, dipyridamole-induced myocardial ischemia may be detected in a high percentage of CAD patients, providing a sensitive tool for identifying patients with high-risk coronary artery anatomy.

Physiologic role of coronary PGI2 and PGE2 in modulating coronary vascular response to sympathetic stimulation

To investigate a physiologic role of coronary prostacyclin (PGI2) and prostaglandin E2 (PGE2) 30 patients who were not affected by coronary heart disease were evaluated for coronary hemodynamics and coronary PGI2 and PGE2 production. Inhibition of coronary prostaglandin biosynthesis by ketoprofen (1 mg/kg) or aspirin (15 mg/kg) administered intravenously did not significantly change coronary hemodynamics in resting conditions. In all patients cold pressor tests induced significant increases in coronary blood flow (p less than 0.001) and decreases in coronary vascular resistance (p less than 0.001) without changes in cardiac oxygen extraction and with consequent increases in calculated myocardial oxygen consumption. Simultaneously, a marked increase in coronary PGI2 (as 6-keto-PGF1 alpha) and PGE2 formation was observed (p less than 0.001). Both ketoprofen (1 mg/kg) and aspirin (15 mg/kg) administration completely abolished PGI2 and PGE2 formation that was induced by cold pressor test and caused a paradoxical increase in coronary vascular resistance (ketoprofen: p less than 0.02; aspirin: p less than 0.05). The results of this study support a physiologic role for the coronary prostaglandins in modulating coronary vascular response to sympathetic stimulation in nonischemic patients.

Functional study of T lymphocyte responsiveness in patients with dementia of the Alzheimer type

The autologous mixed lymphocyte reaction (AMLR) was used to study T lymphocytes in a group of patients with dementia of the Alzheimer type (DAT) in order to confirm the observation that their T cell proliferation in AMLR was greater than in age-matched controls, and to investigate other pathways of T cell activation, searching for correlations between immunologic and clinical findings in DAT. The mean proliferative response in AMLR was increased in patients with DAT. No differences between patients and age-matched controls were detected when other pathways of T cell activation were investigated. The degree of response in the AMLR varied among patients with DAT. This fits with the suggestion that the disorder may be a heterogeneous syndrome.

IgG paraproteinemias: a comparative CSF and serum study

In 10 neurologic patients routine isoelectric focusing of CSF and serum revealed monoclonal IgG paraproteinemia (3 multiple myelomas and 7 benign monoclonal gammopathies). Quantitative protein study showed blood-brain barrier damage in 7 out of 10 patients; 2 patients had intrathecal synthesis of IgG measurable by Reiber's formula. Each case showed identical monoclonal IgG pattern in CSF and serum at isoelectric focusing and immunofixation. We suppose that monoclonal IgG detectable in the CSF usually derive from the serum across the intact or damaged barrier. The occurrence of quantifiable intrathecally synthesized IgG in 2 patients, both with skeletal lesions close to the subarachnoid spaces, and the identical patterns of IgG in CSF and serum suggest that tumoral plasma cells secrete monoclonal IgG into blood and CSF from the bone location.

Oligoclonal and polyclonal synthesis of IgG in the central nervous system: an isoelectric focusing study

The IgG pattern in isoelectric focusing (IEF) has been studied in 90 paired samples of cerebrospinal fluid (CSF) and sera obtained from patients in which intrathecal synthesis of IgG without barrier damage was detectable by Reiber's graph and formula (1980, J. Neurol. 224, 89). Thirty patients were affected by multiple sclerosis (MS), 30 by other inflammatory nervous diseases (OID), and 30 by noninflammatory nervous diseases (NID). At IEF two distinct pathological patterns of CSF IgG were detected: oligoclonal bands (OB), prevailing in the MS group (83% of cases), and a "polyclonal"--i.e., diffuse, uniform--increase of CSF IgG, prevailing in the NID (90%). The OID group was intermediate, 57% of cases with OB and 43% with polyclonal CSF IgG patterns. Overall, only 45 of 90 patients synthesizing IgG in the CNS had CSF OB. This suggests that the CNS immune response can imply either the synthesis of IgG of restricted heterogeneity (i.e., OB) or a polyclonal IgG synthesis, giving in IEF a serum-like pattern to the CSF.

Cerebrospinal fluid and neuropathological study in Devic's syndrome. Evidence of intrathecal immune activation

Cerebrospinal fluid (CSF) was studied in 2 cases of Devic's syndrome (DS). In one of these cases autopsy was carried out. The main CSF feature in DS is the association of blood-brain barrier damage and intrathecal IgG synthesis. These findings are in keeping with our neuropathological observation of diffuse central nervous system vasculitis and leptomeningitis. As a whole, our CSF and neuropathological findings in DS are consistently different from those in multiple sclerosis.

Evidence of T-lymphocyte functional impairment in Huntington's disease

Huntington's Disease (HD) is a degenerative neurological disorder with autosomal dominant transmission. Although immunological defect(s) have been postulated, no confirmed laboratory evidence for this exists. In the present study we observed activated T cells in the peripheral blood of HD patients (using 4F2 monoclonal antibody), whereas the percentage of T cells bearing T-cell activation markers such as HLA-DR and MLR4 antigens was normal. We then studied T cells of HD patients in some functional assays. Since it has been suggested that autologous mixed lymphocyte reaction (AMLR) includes several immune mechanisms in which distinct cell subsets interact and perform distinct regulatory functions, it is conceivable that the remarkable deficiency of AMLR herein observed in HD patients results from some abnormal immune regulation which may contribute to the pathology of this condition. Additional experiments demonstrated a defect of AMLR in three asymptomatic young sibs of HD patients, and coculture experiments between T cells of patients (as responders) and non-T cells of their sibs (as stimulators), and vice versa, produced no proliferative response. Subnormal responsiveness in allogeneic MLR was also observed. Normal or enhanced PHA-induced production of both IL-2 and IFN-gamma in vitro was detected. These experimental data suggest a cellular branch of the immune system in HD; however, they do not indicate if this defect is primary or secondary to the disease itself.

Thalamic dementia: report of a case with unusual lesion location

Thalamic dementia usually results from a bilateral paramedian thalamic infarction. We report a case with typical clinical and neuropsychological features of thalamic dementia, but with CT evidence of an unusual and asymmetrical location of ischemic lesions. Somatosensory evoked potential recordings were consistent with a left medial thalamic infarction, associated with a contralateral lesion, possibly at lemniscal level. This case suggests that thalamic dementia may develop following a unilateral paramedian thalamic infarction.

A simple method to detect intrathecal production of specific antimeasles antibodies in cerebrospinal fluid during subacute sclerosing panencephalitis

The intrathecal production of antimeasles antibodies was studied using the enzyme-linked immunosorbent assay in eight specimens of serum and cerebrospinal fluid (CSF) from patients with clinical signs of subacute sclerosing panencephalitis (SSPE). The test was performed using a 1:5 dilution of CSF and a 1:2000 dilution of serum (ratio 1:400) in order to nullify the physiological gradient of immunoglobulins across the blood brain barrier (BBB). This procedure allowed a rapid and accurate assessment of the synthesis of specific immunoglobulins in the CSF and a good evaluation of the permeability of the BBB. A diagnosis of SSPE was provided in five out of eight patients with clinical signs of the disease. Clinical follow-up confirmed the diagnosis of SSPE in the group of patients with clear evidence of intrathecal synthesis of antimeasles antibodies.

The integrity of the blood-brain barrier in Alzheimer's type and multi-infarct dementia evaluated by the study of albumin and IgG in serum and cerebrospinal fluid

Albumin and IgG have been determined in the serum and cerebrospinal fluid (CSF) of 64 patients affected by Alzheimer's disease and senile dementia of Alzheimer type (SDAT/AD), 17 multi-infarct dementia (MID) patients and 52 controls. The concentrations of albumin and IgG in the serum and CSF have been taken into account to evaluate the integrity of the blood-brain barrier (BBB) and the occurrence of intrathecal immunological activation in demented patients. Clear-cut signs of BBB damage have been shown only in the group of patients affected by MID, whilst none of the two groups of patients displayed signs of immunological activation, expressed by an increase in IgG index, nor abnormally low CSF/serum ratios for IgG, previously suggested as expressive of a "consumption" of IgG by the brain parenchyma.

Cerebrospinal fluid (CSF) findings in amyotrophic lateral sclerosis

The cerebrospinal fluid (CSF) was examined in 90 amyotrophic lateral sclerosis (ALS) patients and in 50 age-matched normal controls. Total protein concentration was significantly higher in ALS patients than in normal controls. CSF IgG and albumin, quantitatively determined by single radial immunodiffusion, were significantly increased in ALS. No difference in serum concentrations was observed between ALS patients and normal controls. On isoelectric focusing a clearcut "fingerprint" pattern was observed in 11 of 12 cases. These findings support the hypothesis that blood-brain barrier damage occurs in ALS. The finding of a higher mononuclear cell count in young ALS patients is briefly discussed in the light of the hypothesis that an exogenous agent might be of some relevance in pathogenesis. An alteration of at least one of the CSF parameters considered was found in 45.5% of ALS cases.

Echocardiographic evaluation with hemodynamic correlation of the left ventricle in mitral stenosis

The value of echocardiographic measurement of left ventricle volume and ejection fraction and of mitral valve area in patients with mitral stenosis has been assessed. All patients referred because of mitral stenosis have been studied by M-mode and two-dimensional echocardiography, by right and left heart catheterization, ventriculography and selective coronary angiography. Patients with other congenital or acquired heart disease or with coronary artery disease were excluded from this study. The selection lead to a series of 39 pts, all with a typical history of Rheumatic Fever: all these pts were divided in three groups according to the degree of mitral stenosis, classified as "mild", if valvular area was greater than 1.8 cm2 (8 pts), "moderate" between 1-1.8 cm2 (15 pts) and "severe" if valvular areas was less than 1 cm2 (16 pts). In all groups echocardiography underestimated left ventricular volumes as well as stroke volumes. Statistical correlation has not been excellent: the best result was again obtained in the calculation of ejection fraction (r = 0.91, P less than 0.001), confirming our previous results in a group of patients with mitral regurgitation. Cross-sectional two-dimensional echocardiography has confirmed, furthermore, as a sensitive and suitable procedure in assessing the mitral valve area (r = 0,87 P less than 0.001); at our experience echocardiography under-estimate mitral area in the cases of severe mitral stenosis.

Opiate receptors and anterior pituitary hormone secretion in man. Effect of naloxone infusion

The role of endogenous opioid receptors on anterior pituitary hormone secretion was evaluated by the administration of the opioid receptor antagonist naloxone. The infusion of naloxone (8 mg iv followed by 4mg/h for 3 h) did not alter basal growth hormone (GH), prolactin (Prl) and thyrotrophin (TSH) secretion but produced a significant rise in cortisol and gonadotrophins in normal man. The infusion of the opiate antagonist appeared to increase the rate and amplitude of luteinizing hormone (LH) pulsatility. Naloxone pre-medication (10 mg iv 30 min before testing) did not alter the pituitary response to TRH and LRH stimulation. These results demonstrate that naloxone can modify basal anterior pituitary hormone secretion and strongly suggest an endogenous opioid modulation of some of these hormones.