Vitamin D deficiency as a predictor of poor prognosis in patients with acute respiratory failure due to COVID-19.

PURPOSE: Hypovitaminosis D is a highly spread condition correlated with increased risk of respiratory tract infections. Nowadays, the world is in the grip of the Coronavirus disease 19 (COVID 19) pandemic. In these patients, cytokine storm is associated with disease severity. In consideration of the role of vitamin D in the immune system, aim of this study was to analyse vitamin D levels in patients with acute respiratory failure due to COVID-19 and to assess any correlations with disease severity and prognosis. METHODS: In this retrospective, observational study, we analysed demographic, clinical and laboratory data of 42 patients with acute respiratory failure due to COVID-19, treated in Respiratory Intermediate Care Unit (RICU) of the Policlinic of Bari from March, 11 to April 30, 2020. RESULTS: Eighty one percent of patients had hypovitaminosis D. Based on vitamin D levels, the population was stratified into four groups: no hypovitaminosis D, insufficiency, moderate deficiency, and severe deficiency. No differences regarding demographic and clinical characteristics were found. A survival analysis highlighted that, after 10 days of hospitalization, severe vitamin D deficiency patients had a 50% mortality probability, while those with vitamin D ≥ 10 ng/mL had a 5% mortality risk (p = 0.019). CONCLUSIONS: High prevalence of hypovitaminosis D was found in COVID-19 patients with acute respiratory failure, treated in a RICU. Patients with severe vitamin D deficiency had a significantly higher mortality risk. Severe vitamin D deficiency may be a marker of poor prognosis in these patients, suggesting that adjunctive treatment might improve disease outcomes.

Heat stress on oocyte or zygote compromises embryo development, impairs interferon tau production and increases reactive oxygen species and oxidative stress in bovine embryos produced in vitro.

Interferon tau (IFNT) is the cytokine responsible for the maternal recognition of pregnancy in ruminants and plays a role modulating embryo-maternal communication in the oviduct inducing a local response from immune cells. We aimed to investigate IFNT production, reactive oxygen species, and oxidative stress under the influence of heat stress (HS) during different stages of bovine in vitro embryo production. HS was established when the temperature was gradually raised from 38.5°C to 40.5°C in laboratory incubator, sustained for 6 hr, and decreased back to 38.5°C. To address the HS effects on IFNT production, reactive oxygen species, and oxidative stress, ovaries from a slaughterhouse were used according to treatments: control group (38.5°C); oocytes matured under HS; oocytes fertilized under HS; zygotes cultured in the first day under HS; and cells submitted to HS at oocyte maturation, fertilization, and the first day of zygote culture. The HS negatively affected cleavage and blastocyst rates, in all HS groups. On Day 7, all HS-treated embryos showed decrease IFNT gene and protein expressions, whereas reactive oxygen species were increased in comparison to the control. In conclusion, the compromised early embryo development due to higher temperatures during in vitro oocyte maturation, fertilization, and/or zygote stage have diminished IFNT expression and increased reactive oxygen species in bovine.

Performance of Indocyanine green for sentinel lymph node mapping and lymph node metastasis in colorectal cancer: a diagnostic test accuracy meta-analysis.

BACKGROUND: Indocyanine green has been widely employed as a secure and easy technique for sentinel lymph node mapping in different types of cancer. Nonetheless, the usage of Indocyanine green has not been fully implemented due to the heterogeneous results found in published studies. Thus, the objective of this meta-analysis is to evaluate the overall performance of Indocyanine green for sentinel lymph node mapping and node metastasis in patients undergoing colorectal cancer surgery. METHODS: An extensive systematic search was performed to identify relevant studies in English and Spanish with no time limit restrictions. For the meta-analysis, a hierarchical summary receiver operating characteristic curve (HSROCs) was constructed, and quantitative data synthesis was performed using random effects models. Specificity, sensitivity, positive, and negative likelihood ratios were obtained from the corresponding HSROC. Between-study heterogeneity was visually evaluated using Galbraith plot, and publication bias was quantified using Deeks' method. RESULTS: A total of 11 studies were included for analysis. The pooled detection rate for sentinel lymph node mapping was 91% (80-98%). Covariates significantly influencing the pooled detection rate were having colon cancer (estimate: 1.3001; 1.114 to 1.486; p < 0.001) and the usage of a laparoscopic approach (estimate: 1.3495; 1.1029 to 1.5961; p < 0.001). The performance of Indocyanine green for the detection of metastatic lymph nodes yielded an area under the roc curve of 66.5%, sensitivity of 64.3% (51-76%), and specificity of 65% (36-85%). CONCLUSIONS: Indocyanine green for the detection of sentinel lymph node mapping demonstrates better accuracy when used in colonic cancer and by a laparoscopic approach. Nevertheless, its overall performance for the detection of lymph node metastasis is poor.

Molecular mechanisms driving Streptococcus mitis entry into human gingival fibroblasts in presence of chitlac-nAg and saliva.

The molecular mechanisms leading to Streptococcus mitis capability of entering oral cells were investigated in a co-culture of S. mitis and Human Gingival Fibroblasts (HGFs) in the presence of saliva. An innovative colloidal solution based on silver nanoparticles (Chitlac-nAg), a promising device for daily oral care, was added to the experimental system in order to study the effects of silver on the bacterial overgrowth and ability to enter non-phagocytic eukaryotic cells. The entry of bacteria into the eukaryotic cells is mediated by a signalling pathway involving FAK, integrin ß1, and the two cytoskeleton proteins vinculin and F-actin, and down-regulated by the presence of saliva both at 3 and 48 h of culture, whereas Chitlac-n Ag exposure seems to influence, by incrementing it, the number of bacteria entering the fibroblasts only at 48 h. The formation of fibrillary extrusion from HGFs and the co-localization of bacteria and silver nanoparticles within the fibroblast vacuoles were also recorded. After longer experimental times (72 and 96 h), the number of S. mitis chains inside gingival cells is reduced, mainly in presence of saliva. The results suggest an escape of bacteria from fibroblasts to restore the microbial balance of the oral cavity.

MRJF4, a novel histone deacetylase inhibitor, induces p21 mediated autophagy in PC3 prostate cancer cells.

Autophagy is a cellular defense mechanism which occurs through degradation and recycling of cytoplasmic constituents and represents a caspase—independent alternative to cell death by apoptosis. It is generally accepted that the suppression of autophagy in many cancer cells is directly correlated to malignancy; hence, the control of autophagy genes could represent a target for cancer therapy. The inhibition of cell proliferation through autophagy activation could be an important mechanism for many anti—tumor drugs. Here we report the effects of a novel histone deacetylase inhibitor MRJF4 (racemic mixture) and of its two enantiomers [(+)—MRJF4 and (—)—MRJF4] on the morphological and molecular mechanisms causing death and migration of PC3 prostatic cancer cells. In particular, we investigated the occurrence of the autophagic process, both at morphological and molecular levels (LC3 expression), and its relationship with p21, a key molecule which regulates cell cycle and autophagy cell death. Moreover, pERK/Nf—kB driven intracellular signaling, the expression of MMP9 protein — a key component of cell migration — invasion, and metastasis were assayed. Our results showed that the anti—proliferative effects of MRJF4 due to autophagy occurrence, documented by LC3 increase and ultrastructural modifications, and the reduction of invasiveness seem to be mediated by the down—regulation of pERK/NF—kB signaling pathway, along with p21 up—regulation.

A dual role for ß1 integrin in an in vitro Streptococcus mitis/human gingival fibroblasts co-culture model in response to TEGDMA.

AIM: To evaluate the effect of TEGDMA on human gingival fibroblasts (HGFs) in vitro co-cultured with Streptococcus mitis, focusing on the signalling pathways underlying cell tissue remodelling and inflammatory response processes. METHODOLOGY: ß1 integrin expression was evaluated by means of imaging flow cytometry. The Western blot technique was used to investigate the expression of protein kinase C (PKC), extracellular signal-regulated kinase (ERK), matrix metalloproteinase 9 (MMP9) and 3 (MMP3). RT-PCR was performed to quantify nuclear factor-kb subunits (Nf-kb1, ReLa), IkB kinase ß (IkBkB), cyclooxygenase II (COX-2) and tumour necrosis factor-α (TNF-α) mRNA levels. Statistical analysis was performed using the analysis of variance (anova). RESULTS: When HGFs are co-cultured with S. mitis, ß1 integrin intensity, phosphorylated PKC (p-PKC), activated ERK (p-ERK), IkBkB mRNA level and MMP9 expression increased (for all molecules P < 0.05 HGFs versus HGFs co-cultured with S. mitis). A higher level of MMP3 in HGFs treated with TEGDMA was recorded (P < 0.05 HGFs versus HGFs exposed to TEGDMA). COX-2 inflammatory factor mRNA level appeared higher in HGFs exposed to 1 mmol L(-1) TEGDMA (P < 0.01 HGFs versus HGFs exposed to TEGDMA), whereas TNF-α gene expression was higher in HGFs co-cultured with S. mitis (P < 0.05 HGFs versus HGFs co-cultured with S. mitis). CONCLUSIONS: ß1 integrin triggered the signalling pathway, transduced by p-PKCα and involving ERK 1 and 2 and MMPs. This pathway resulted in an unbalanced equilibrium in tissue remodelling process, along with inflammatory response when HGFs are exposed to bacteria or biomaterial alone. On the contrary, the TEGDMA/S. mitis combination restored the balance between extracellular matrix deposition and degradation and prevented an inflammatory response.

NF-kB mediated down-regulation of collagen synthesis upon HEMA (2-hydroxyethyl methacrylate) treatment of primary human gingival fibroblast/Streptococcus mutans co-cultured cells.

PURPOSE: In vitro studies have evidenced the cytotoxic effect of HEMA (2-hydroxyethyl methacrylate), the most common component of dental resin-based restorative material, which is released within the oral cavity, on eukaryotic cells such as gingival fibroblast and epithelial cells. However, since the presence of microorganisms within the oral cavity cannot be excluded and little is known about the interactions occurring between eukaryotic cells and the human oral microbiota, our attention has been addressed to investigate the effect of 3 mM HEMA on the molecular mechanisms driving the response of human gingival fibroblasts (HGFs) co-cultured with Streptococcus mutans. METHODOLOGY: HGF/S. mutans co-culture has been set up in our lab, and upon HEMA treatment, S.mutans and HGF cells' viability and adhesion along with type I collagen gene and pro-collagen I, Bax, Bcl2, nuclear factor kB (NF-kB), IkBα, pIkBα protein expression by PCR, Western blotting and ELISA assays have been investigated. RESULTS: HEMA treatment determines a significant decrease of type I collagen protein production, even in the presence of S. mutans, in parallel to a decrease of cell viability and adhesion, which seem to be regulated by NF-kB activation. In fact, when SN50, NF-kB-specific pharmacological inhibitor, is added to the culture, cell proliferation along with collagen synthesis is restored. CONCLUSION: The modulation exerted by S. mutans on the cytotoxic effect of HEMA suggests that within the oral cavity, the eukaryotic/prokaryotic cell interactions, maintaining the balance of the environment, allow HEMA to perform its adhesive and bonding function and that the use of a co-culture system, which simulates the oral cavity organization, improves the knowledge concerning the biocompatibility of this dental material.

Early induction of luteolysis in a timed AI protocol increases reproductive performance in beef cows.

The aim of this study was to produce a longer proestrus by early administration of prostaglandin F2α (PGF) in a timed artificial insemination (TAI) protocol in non-suckling Bos taurus (Angus crossbreed) beef cows. On day 0, cows (n = 489) were treated with an intravaginal 1 g progesterone (P4) device and 2 mg of estradiol benzoate. On day 7, cows were randomized into two groups: PGF7(n = 244; 500 µg of sodium cloprostenol 24 h before P4 device removal) or PFG8 (n = 245; 500 µg of sodium cloprostenol at P4 device removal). On day 8, P4 device was removed and cows received 0.5 mg of estradiol cypionate. All cows were submitted to TAI on day 10 (48-50 hours after P4 device removal). Cows treated with PGF on day 7 had greater expression of estrus (91.3 vs 79.1 %; P = 0.0011), regardless of CL presence at beginning of the protocol. Cows from PGF7 group had lower circulating P4 concentrations on day 8 in comparison with PGF8 treated cows (1.86 vs 2.99 ng/mL; P < 0.001). However, preovulatory follicle diameter did not differ among treatments at TAI (11.9 vs 11.8 mm; P = 0.7881). Pregnancy per TAI (P/TAI) was greater for PGF7 (63.9 vs 50.6 %; P = 0.0114) than PGF8 treated cows. In cows with follicles <8.5 mm at TAI, expression of estrus (33.3 vs 26.6 %; P = 0.6427) and P/TAI (40 vs 26.6 %; P = 0.3657) were low in both PGF7 and PGF8 treated cows, respectively. In cows with medium follicle size (8.5 to 11.9 mm) PGF7 treated cows had greater expression of estrus (90.5 vs 80 %; P = 0.033) and P/TAI (62.2 vs 49 %; P = 0.053). In cows with follicles >12 mm, expression of estrus was greater for PGF7 than PGF8 treated cows (99.1 vs 93.3 %; P = 0.045), however P/TAI did not differ (68.2 vs 59 %; P = 0.149). In cows with P4 < 1.99 ng/mL on day 8, expression of estrus was similar between PGF7 and PGF8 treated cows (92.6 vs 90.4 %; P = 0.53), and P/TAI tended to be greater for PGF7 than PGF8 treated cows (63 vs 52.1 % P = 0.076). However, in cows with P4 > 2 ng/mL PGF7 cows had higher expression of estrus (89 vs 67.5 %; P = 0.0005) and P/TAI (64.8 vs 48.7 %; P = 0.021) than PGF8. Thus, increasing the proestrous period by inducing luteolysis 24 hours earlier than removing the P4 intravaginal device enhanced fertility in non-suckling cyclic beef cows by increasing expression of estrus and P/TAI.

pPKCα-mediated effect on in vitro Aß production in response to gamma secretase inhibitor LY411575 in rat CTXTNA2 astrocytes.

Alzheimer's Disease implies memory and cognitive impairment due to beta amyloid accumulation, presence of reactive microglia and astrocytes, loss of synapses, neural network dysfunctions and modifications of neuronal signalling. A key role in such events is played by astrocytes, which actively secrete high levels of beta amyloid protein originating from sequential cleavage of APP by alpha, beta and gamma secretases. Since inhibition of such process could represent an important strategy against the occurrence of Alzheimer's Disease, in this paper the role played by pPKC alpha in the in vitro beta amyloid production in response to gamma secretase inhibitor in rat cortical astrocytes is reported. pPKC alpha increased expression seems to be related to decreased beta amyloid production in parallel to increased astrocytes viability and decreased iNOS expression in the presence of 10 microM LY411575. Thus gamma secretase inhibitor, activating pPKC alpha intracellular pathway could be suggested to prevent or reduce downstream toxic events, representing a useful strategy to counteract Alzheimer's disease.

Machine learning based approach to pH imaging and classification of single cancer cells.

The ability to identify different cell populations in a noninvasive manner and without the use of fluorescence labeling remains an important goal in biomedical research. Various techniques have been developed over the last decade, which mainly rely on fluorescent probes or nanoparticles. On the other hand, their applications to single-cell studies have been limited by the lengthy preparation and labeling protocols, as well as issues relating to reproducibility and sensitivity. Furthermore, some of these techniques require the cells to be fixed. Interestingly, it has been shown that different cell types exhibit a unique intracellular environment characterized by specific acidity conditions as a consequence of their distinct functions and metabolism. Here, we leverage a recently developed pH imaging modality and machine learning-based single-cell segmentation and classification to identify different cancer cell lines based on their characteristic intracellular pH. This simple method opens up the potential to perform rapid noninvasive identification of living cancer cells for early cancer diagnosis and further downstream analyses.

NAD(P)H oxidase and pro-inflammatory response during maximal exercise: role of C242T polymorphism of the P22PHOX subunit.

Intense exercise induces a pro-inflammatory status through a mechanism involving the NAD(P)H oxidase system. We focused our attention on p22phox, a subunit of the NAD(P)H oxidase, and on its allelic polymorphism C242T, which is known to affect the functional activity of the enzyme. We investigated whether the p22phox C242T variants exhibit systemic effects in healthy subjects by analyzing the proinflammatory and cardiocirculatory responses to physical exercise in endurance athletes. The group of study consisted of 97 long distance runners, 37 +/- 4.4 yrs of age, with similar training history. The subjects underwent a maximal stress test during which both inflammatory and cardiopulmonary parameters were monitored. Our results demonstrate that T allele deeply influences the neutrophil activation in response to intense exercise, since T carriers were characterized by significantly lower release of myeloperoxidase (MPO), a classical leukocyte derived pro-inflammatory cytokine. In addition, the presence of T allele was associated with a higher cardiopulmonary efficiency as evidenced by a significantly lower Heart Rate (HR) at the peak of exercise and, when a dominant model was assumed, by a higher maximal oxygen uptake (VO2 max). On the other hand, no effects of 242T mutation on the plasmatic total antioxidant capacity (TAC) and on the cortisol responses to the physical exercise were detected. In conclusion, our data support a systemic role for p22phox C242T polymorphism that, modifying the intensity of the inflammatory response, can influence the cardiovascular adaptations elicited by aerobic training. These results contribute to support the hypothesis of a systemic effect for the C242T polymorphism and of its possible functional rebound in healthy subjects.

Self-defending additively manufactured bone implants bearing silver and copper nanoparticles.

Effective preventive measures against implant-associated infection (IAI) are desperately needed. Therefore, the development of self-defending implants with intrinsic antibacterial properties has gained significant momentum. Biomaterials biofunctionalized with silver (Ag) have resulted in effective antibacterial biomaterials, yet regularly induce cytotoxicity. In this study, the use of both Ag and copper (Cu) nanoparticles (NPs) on TiO2 surfaces was investigated to generate antibacterial and osteoconductive biomaterials. Hence, additively manufactured Ti-6Al-4V volume-porous implants were biofunctionalized with plasma electrolytic oxidation (PEO) through the incorporation of varying ratios of Ag and/or Cu NPs in the TiO2 layer covering the implant surface. For all experimental groups, the surface morphology, chemical composition, ion release profile, generation of reactive ion species, antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) in vitro and ex vivo, as well as the response of pre-osteoblastic MC3T3-E1 cells in metabolic activity and differentiation assays were determined. PEO biofunctionalization resulted in rough and highly porous surfaces that released Ag and Cu ions for 28 days and generated hydroxyl as well as methyl radicals. A strong synergistic bactericidal behavior between Ag and Cu ions was detected, which allowed to decrease the concentration of Ag ions by 10-fold, while maintaining the same level of antibacterial activity. Antibacterial agar diffusion and quantitative assays indicated strong antibacterial activity in vitro for the implants containing Ag and Ag/Cu, while no antibacterial activity was observed for implants bearing only Cu NPs. Moreover, the biofunctionalized implants with ratios of up to 75% Ag and 25% Cu NP totally eradicated all bacteria in an ex vivo model using murine femora. Meanwhile, the biofunctionalized implants did not show any signs of cytotoxicity, while implants bearing only Cu NPs improved the metabolic activity after 7 and 11 days. The biomaterials developed here, therefore, exploit the synergistic behavior of Ag and Cu to simultaneously offer strong antibacterial behavior while fully mitigating the cytotoxicity of Ag against mammalian cells.

Oncostatin M and its receptors mRNA regulation in bovine granulosa and luteal cells.

Oncostatin M (OSM) and its receptor (OSMR) are members of the interleukin-6 family cytokines. Although OSM and OSMR expression was detected in human ovaries, their function and regulation during follicle development, ovulation and luteolysis have not been studied in any species. The aim of the present study was to investigate the levels of OSM and OSMR mRNA in bovine ovaries and the effect of OSM treatment on cultured granulosa cells. OSM mRNA was not detected in granulosa cells obtained from follicles around the time of follicular deviation and from pre-ovulatory follicles, whereas OSMR transcript levels were greater in granulosa cells of atretic subordinate follicles (P < 0.001). Abundance of OSMR mRNA increased in granulosa cells of preovulatory follicles, collected at 12 and 24 h after the ovulatory stimulus with gonadotropins (P < 0.001). In the luteal tissue, OSM mRNA abundance levels were higher at 24-48 h after PGF-induced luteolysis (P < 0.01) compared to 0 h, whereas OSMR mRNA was transiently increased at 2 h after PGF treatment (P < 0.05). In cultured granulosa cells, 10 ng/mL OSM in the presence of FSH increased BAX/BCL2 mRNA ratio (P < 0.05) compared to the control. Moreover, 100 ng/mL OSM in the presence of FSH increased OSMR (P < 0.05) and decreased XIAP mRNA (P < 0.05) levels, compared to the control group. These findings provide the first evidence that OSMR is regulated during follicle atresia, ovulation and luteolysis, and that OSM from other cells may mediate granulosa and luteal cell function, regulating the expression of genes involved in cell's viability.

Interferon mediated phosphatidylinositol uptake and processing in nuclei isolated from Burkitt lymphoma cells.

The kinetic analysis of exogenous [3H]phosphatidylinositol (PI) uptake and processing by nuclei isolated from Daudi lymphoma cells upon interferon alpha treatment has been performed. Results have disclosed that, with respect to controls, interferon induces an evident stimulation of label incorporation into nuclei. The incorporated [3H] PI has been found for phosphorylation and hydrolytic cleavage, indicating that the intranuclear transduction system activated by interferon at plasma membrane level, might involve the PI cycle as a possible route of intracellular signalling.

Role of exploratory laparoscopy in haemodynamically stable patient with a penetrating abdominal trauma.

A young lady presented to the hospital following a penetrating abdominal trauma. She was haemodynamically stable during the initial assessment. Despite fruitless finding from blood test, plain radiograph and computed tomographic scanning, a bowel contusion was found during an explorative laparoscopy. Here, we highlight the need for laparoscopy as a diagnostic and therapeutic tool in haemodynamically stable patient with a penetrating abdominal trauma.

Dental pulp lipids from Bos taurus during odontogenesis.

During the fetal development of the dental pulp, the various lipid classes show no substantial differences in their relative ratios but differences occur between deciduous and permanent teeth. By chromatography, the amount of free cholesterol was found decreased in deciduous and permanent teeth as compared to fetal teeth. Esterified cholesterol increased in permanent teeth and triglyceride levels were high only in developing permanent teeth. Phosphatidylcholine, sphingomyelin and phosphatidylserine were present in higher concentration in permanent unerupted teeth, while phosphatidylethanolamine was at first constant but then decreased during development in the permanent unerupted teeth. These data suggest that lipid changes are related to the assembly of plasma membranes and to the establishment of the innervation during ontogeny and postnatal development of dental pulp.

[Usefulness of a complete echographic evaluation of the atrial dimensions for the diagnosis of idiopathic atrial fibrillation]. / Utilità di una valutazione ecografica completa delle dimensioni atriali per la diagnosi di fibrillazione atriale "idiopatica".

Left atrial enlargement may occur sometimes through only the increase of the supero-inferior (S-I) diameter, with normality of the antero-posterior (A-P) and latero-medial dimensions. In this study, both the largest dimensions of the left atrium and S-I and transversal dimensions of the left atrium and S-I and transversal dimensions of the right atrium were investigated, among the 98 pts suffering from recurrent paroxysms of atrial fibrillation (FAP). On the basis of the clinical, ECGraphic and echocardiographic data, a subgroup of 78 pts has been found, with FAP reliable to heart disease, which mostly appeared as accompanying a finding of atrial enlargement--left or right or both--. The remaining 20 pts distinguished, by means of the echocardiographic findings, as following: a) "idiopathic" FAP, neither dependent on heart disease nor on atrial enlargement (no. 11 pts); b) FAP dependent on "unexplained" atrial enlargement, i.e. unreliable to definite cardiac pathology (no. 9 pts). Among the b) pts, 7 showed the only, isolated S-I dimension increased. Therefore, the determination of the all largest dimensions of the atria, in pts with recurrent FAP, appeared able to more carefully distinguish the true cases of "idiopathic" FAP.

[Differences in the symptomatology of paroxysmal supraventricular tachycardias in relation to the different sites of localization of the arrhythmic reentry circuit. Clinical picture, semiologic and genetic aspects]. / Diversità di sintomatologia nelle tachicardie parossistiche sopraventricolari (TPSR) correlata alla differente localizzazione del circuito aritmico di rientro. Analisi del quadro clinico e considerazioni semeiogenetiche.

Transesophageal, electrophysiologic studies were conducted in 47 patients, with clinical and ECGgraphic diagnosis of paroxysmal reciprocating supraventricular tachycardia. After admission to hospital, the patients were enrolled in the study in accordance with the criterion concerning the exclusion of patients with signs and symptoms of severe heart pump failure (ie, NYHA III and IV class were excluded). The transesophageal study was performed during paroxysmal tachycardia in each patient to measure the V-A interval and to localize the site of reentry. Thereby, the patients could be grouped into 2 subsets, ie those with A-V nodal reentrant tachycardia (no. 30 patients) and those with accessory pathway reentrant tachycardia (no. 17 patients). Moreover, the prevalence in both subsets was evaluated in the following signs and symptoms: palpitations, dyspnoea, chest pain, pulsations in the neck, significant increase in urinary output, hypotension, dizziness, near-syncope, syncope, shock, focal brain injury. From the data analysis, significantly greater prevalence of palpitations in the neck resulted in the subset of patients with reentry confined to the A-V node (no. 20 cases) compared with those suffering from reentry via accessory pathway (no. 4 cases). Moreover the arterial pressure, in A-V nodal reentrant tachycardia, showed the lowest values and the best decreases, together with the finding of a more rapid trend to decline in comparison with the accessory pathway subset. On the other hand, no significant differences could be seen about the remaining symptoms. In an attempt to provide the reliable explanation for the differences found between the 2 subsets of study, concerning both the unpleasant pulsations in the neck and the pressure decrease, we postulated a remarkable role for the length of arrhythmic circle movement. The smaller dimensions of circuit limbs, in A-V nodal reentrant tachycardia, are likely to be the principle cause of the different clinical features of 2 types of reentry. We speculate actually that in susceptible patients the critical event is most likely to be A-V functional dissociation due to early and unphysiologic activation of atria by stimulus rapidly reentrant from the bottom portion of the AV node: the simultaneous occurrence, frequent in A-V node reentry, of both, atrial and ventricular mechanical activation, would result, however, in impairment of atrial haemodynamics due to development of cannon A waves, able either to activate a vasodepressor reflex from the atria or to stimulate instantaneous release of atrial natriuretic factor in the circulation. Further studies, however, are necessary to be performed on large cases-records, to confirm our hypothesis.(ABSTRACT TRUNCATED AT 400 WORDS)

[Complications of thyroidectomy: hemorrhage]. / Complicanze della tiroidectomia: l'emorragia.

The authors report their experience in haemorrhage after thyroid surgery. Haemorrhagic complications occurred in 5 cases in a series of 1803 sequential thyroidectomies (incidence: 0.27%). In particular, incidence was 1.9% after interventions for thyroid neoplasias (adenoma and carcinoma) and 0.18% after interventions for non-neoplastic thyroid pathology. Haemorrhage occurred always after "total" operations, even if monolateral. Causative and contributing factors, precautions and measures helpful in reducing the incidence and the potential dangerousness of haemorrhagic complications are discussed.