The association between social isolation, loneliness and psychological problems in young adults: A study during the acute phase of COVID-19 in Italy

During the COVID-19 pandemic, governments had to impose social isolation measures to safeguard the citizens' health. However, this could have affected psychological problems. The aim of the present study was to investigate the psychological effects associated with social and emotional isolation during the acute phase of the COVID-19 in Italy. To this purpose, the degree of social isolation and loneliness and the presence of psychological problems (externalising and internalising) were investigated online in a sample of 395 young adults (18-30 years; 57% women). Results confirmed the relevant association between social isolation, loneliness and psychological problems, in both internalising and externalising dimensions. Particularly, loneliness showed the strongest association. Moreover, consistently with surveys conducted during the COVID-19-era, data highlighted that men were more vulnerable to social isolation and loneliness than women. These results underline the need for adequate interpersonal support during moments of isolation to prevent negative effects on psychological problems.

Expanding the Living Donor Pool "Second Act": Laparoscopic Donor Nephrectomy and ABO-Incompatible Kidney Transplantation Improve Donor Recruitment

BACKGROUND

To safely expand our living donor pool, we recently decided to work on 3 areas: analysis of causes of exclusion of potential donors, the results of which we recently published, introduction of laparoscopic donor nephrectomy (LDN), and ABO-incompatible (ABOi) transplantation. We sought to determine the impact of the new strategy on living donor recruitment and transplantation during over a 10-year period at a single institution.

METHODS

From January 2005 to September 2014, we evaluated 131 living donors. Of these, 80 (61%) were genetically related, 51 (39%) unrelated, 119 (91%) ABO compatible (ABOc), 12 ABOi (9%). The analysis was divided into 2 eras: era 1, 2005-2010 (n = 53) included the use of open lumbotomy and acceptance of ABOc only; and era 2, 2011-2014 (n = 78), which saw the introduction of LDN and ABOi transplantation.

RESULTS

Forty-five (34%) potential candidates successfully donated, 67 (51%) were excluded, and 19 (15%) were actively undergoing evaluation. Overall, 53 potential donors were evaluated in era 1 (8.8 donors/year), 78 in era 2 (19.5 donors/year). There were fewer excluded donors in era 2 vs era 1 (62% era 1 vs 44% era 2), and living donor kidney transplantation (LDKT) significantly increased in era 2 vs era 1 (3.3/year era 1 vs 7.1/year era 2). The establishment of an ABOi LDKT program led to a 15% increase of evaluations in era 2 (12/78 donors).

CONCLUSIONS

LDN along with ABOi LDKT allowed for an improvement in recruitment of living donors and corresponding LDKT.

Managing atypical and typical herpetic central nervous system infections: results of a multinational study

There have been many studies pertaining to the management of herpetic meningoencephalitis (HME), but the majority of them have focussed on virologically unconfirmed cases or included only small sample sizes. We have conducted a multicentre study aimed at providing management strategies for HME. Overall, 501 adult patients with PCR-proven HME were included retrospectively from 35 referral centres in 10 countries; 496 patients were found to be eligible for the analysis. Cerebrospinal fluid (CSF) analysis using a PCR assay yielded herpes simplex virus (HSV)-1 DNA in 351 patients (70.8%), HSV-2 DNA in 83 patients (16.7%) and undefined HSV DNA type in 62 patients (12.5%). A total of 379 patients (76.4%) had at least one of the specified characteristics of encephalitis, and we placed these patients into the encephalitis presentation group. The remaining 117 patients (23.6%) had none of these findings, and these patients were placed in the nonencephalitis presentation group. Abnormalities suggestive of encephalitis were detected in magnetic resonance imaging (MRI) in 83.9% of the patients and in electroencephalography (EEG) in 91.0% of patients in the encephalitis presentation group. In the nonencephalitis presentation group, MRI and EEG data were suggestive of encephalitis in 33.3 and 61.9% of patients, respectively. However, the concomitant use of MRI and EEG indicated encephalitis in 96.3 and 87.5% of the cases with and without encephalitic clinical presentation, respectively. Considering the subtle nature of HME, CSF HSV PCR, EEG and MRI data should be collected for all patients with a central nervous system infection.

Ruminococcus gnavus E1 modulates mucin expression and intestinal glycosylation

AIMS

The molecular cross-talk between commensal bacteria and the gut play an important role in the maintenance of the intestinal homeostasis and general health. Here, we studied the impact of a major Gram-positive anaerobic bacterium of the human gut microbiota, that is, Ruminococcus gnavus on the glycosylation pattern and the production of intestinal mucus by the goblet cells.

METHODS AND RESULTS

Our results showed that R. gnavus E1 specifically increases the expression and the glycosylation level of the intestinal glyco-conjugates by goblet cells in the colonic mucosa of mono-associated mice with R. gnavus E1 as well as in human HT29-MTX cells. Such an effect was mediated through induction of the level of mRNA encoding for the major intestinal gel-forming mucin such as MUC2 and various glycosyltransferase enzymes.

CONCLUSIONS

This study demonstrates for the first time that R. gnavus E1 possess the ability to modulate the glycosylation profile of the glyco-conjugate molecules and mucus in goblet cells.

SIGNIFICANCE AND IMPACT OF THE STUDY

Furthermore, we demonstrated that R. gnavus E1 modified specifically the glycosylation pattern and MUC2 expression by means of a small soluble factor of peptidic nature (<3 kDa) and heat stable in the HT29-MTX cell.

Efficacy of the "body movement and perception" method in the treatment of fibromyalgia syndrome: an open pilot study

OBJECTIVES

Group exercises may be useful in fibromyalgia syndrome (FMS). The 'Body movement and perception' (BMP) method is based on low impact exercises, awareness of body perception and relaxation, aimed at treating small groups of patients following the Resseguier method (RM) and integrating RM with exercises derived from soft gymnastics. We assessed the effects of BMP method on FMS.

METHODS

40 women with FMS (age and disease duration: 51.7±7.2 and 4.9±3.8 years) participated in an open pilot study. BMP sessions were performer twice a week (50 minutes each) for 8 weeks. Patients were assessed at enrolment (T0) and at the end of the study (T1) by a self-administered questionnaire (temporal characteristics of pain, pain interference in working and recreational activities and in night-time rest, awareness of pain, fatigue, irritability, well-being, quality of movement, ability to focus on perception and to perceive whole body, postural selfcontrol, ability to relax) and a clinical evaluation (tender points, assumption of analgesics/NSAIDs, distribution of pain, pain in sitting and standing position, pain during postural passages and gait, postural body alignment, muscular contractures).

RESULTS

At T1, FMS patients significantly improved with respect to T0 in pain, fatigue, irritability, well-being, quality of movement, postural self-control, ability to relax mind and body, movement perception, tender point scores, assumption of analgesic/NSAIDs, body alignment and muscle contractures (p<0.05 for all the comparisons T1 versus T0).

CONCLUSIONS

In FMS patients, rehabilitation with BMP improves pain and well being, reduces the number of tender points and muscle contractures, thus it is useful in FMS management.

Indeterminate, subcentimetric focal liver lesions in cancer patients: additional role of contrast-enhanced ultrasound

PURPOSE

To evaluate whether the use of contrast-enhanced ultrasound (CEUS) could improve the characterization of indeterminate subcentimetric focal liver lesions (FLLs) seen with multidetector computed tomography (MDCT) in cancer patients.

MATERIALS AND METHODS

For 12 months all patients with extrahepatic tumors showing small (< 10 mm), indeterminate focal liver lesions on whole-body or abdominal computed tomography (CT) underwent immediate, targeted ultrasound (US) to rule out a cystic lesion. Whenever unenhanced US demonstrated a non-cystic lesion or failed to recognize any focal abnormality within the suspected area, CEUS was carried out. During the arterial phase, CEUS was focused on the area reflecting the CT finding, while the entire organ was explored during the portal-sinusoidal phase.

RESULTS

Among the 132 patients with MDCT evidence of indeterminate, subcentimetric focal liver lesions (206 lesions), US proved the cystic nature of 138 lesions in 87 patients. In 45 cases US failed to recognize any abnormality or cystic image and these subjects underwent CEUS. The CEUS results were confirmed by further assessment or follow-up for 43 / 45 patients (3 cysts, 8 hemangiomas, 47 metastases, 2 areas of focal steatosis, 2 eosinophilic necroses, 1 granuloma, 1 abscess, 1 fistula). CEUS failed to detect 3 lesions (1 metastasis and 2 benign lesions). In 8 cases CEUS recognized additional liver metastases.

CONCLUSION

CEUS can be helpful in demonstrating or excluding metastases in cancer patients with MDCT evidence of subcentimetric, indeterminate focal liver lesions.

Symptoms accompanying fibromyalgia

OBJECTIVE

The objective of the study was to investigate the relationship between spontaneous and provoked pain in fibromyalgia and to evaluate the frequency of disturbances associated with muscle pain, including some disturbances which are not usually considered as typical symptoms associated with pain in fibromyalgia.

METHODS

In sixty-seven patients with fibromyalgia the severity of spontaneous pain was assessed by a visual analogue scale and the severity of provoked pain by an original method, which includes the evaluation of the number of tender points and the evaluation of the intensity of provoked pain. The method used to assess the severity of provoked pain is more sensitive than other methods currently used. The occurrence of accompanying symptoms was also evaluated. The investigation included the occurrence of paresthesias of the upper limbs, hemorrhoids and epistaxis, which are not usually considered as typical symptoms associated with fibromyalgia.

RESULTS

No significant correlation was observed between the severity of spontaneous and provoked pain. The following disturbances were more frequent in the examined patients than in general population: headache, chronic fatigue, sleep disorders, irritable bowel syndrome, restless legs syndrome, paresthesias in the upper limbs, hemorrhoids and epistaxis.

CONCLUSIONS

Spontaneous and provoked pain should be considered two independent clinical features of fibromyalgia. Paresthesias in the upper limbs, hemorrhoids and epistaxis should be considered as typical symptoms associated with fibromyalgia. Hemorrhoids and epistaxis are frequently due to a diathesis characterized by laxity of connective tissues and fibromyalgia could be a consequence of such a diathesis.

Sensing X chromosome pairs before X inactivation via a novel X-pairing region of the Xic

Mammalian dosage compensation involves silencing of one of the two X chromosomes in females and is controlled by the X-inactivation center (Xic). The Xic, which includes Xist and its antisense transcription unit Tsix/Xite, somehow senses the number of X chromosomes and triggers Xist up-regulation from one of the two X chromosomes in females. We found that a segment of the mouse Xic lying several hundred kilobases upstream of Xist brings the two Xics together before the onset of X inactivation. This region can autonomously drive Xic trans-interactions even as an ectopic single-copy transgene. Its introduction into male embryonic stem cells is strongly selected against, consistent with a possible role in trans-activating Xist. We propose that homologous associations driven by this novel X-pairing region (Xpr) of the Xic enable a cell to sense that more than one X chromosome is present and coordinate reciprocal Xist/Tsix expression.

Low power radiofrequency electromagnetic radiation for the treatment of pain due to osteoarthritis of the knee

OBJECTIVE

To investigate the analgesic effect of low power radiofrequency electromagnetic radiation (RF) in osteoarthritis (OA) of the knee.

METHODS

In a randomized study on 40 patients the analgesic effect of RF was compared with the effect of transcutaneous electrical nerve stimulation (TENS). RF and TENS applications were repeated every day for a period of 5 days. The therapeutic effect was evaluated by a visual analogue scale (VAS) and by Lequesne's index: tests were performed before, immediately after and 30 days after therapy.

RESULTS

RF therapy induced a statistically significant and long lasting decrease of VAS and of Lequesne's index; TENS induced a decrease of VAS and of Lequesne's index which was not statistically significant.

CONCLUSIONS

A therapeutic effect of RF was therefore demonstrated on pain and disability due to knee OA. This effect was better than the effect of TENS, which is a largely used analgesic technique. Such a difference of the therapeutic effect may be due to the fact that TENS acts only on superficial tissues and nerve terminals, while RF acts increasing superficial and deep tissue temperature.

[Nurse's coworking to electronic medical record]

Nephrologists need to register and look at a great number of clinical data. The use of electronic medical records may improve efficiency and reduce errors. Aim of our work is to report the experience of Villa Scassi Hospital in Genoa, where a "patient file" has been performed to improve nephrology practice management. The file contains all clinical records, laboratory and radiology data, therapy, dialysis clinics, in addition to reports of out-patients department. This system allowed a better efficiency in diagnosis and treatment of the patient. Moreover experience of nurses in employing electronic medical records is reported. A reduced number of errors was found in therapy administering, because of a only one data source for physicians and nurses.

Accurate prediction of autologous stem cell apheresis yields using a double variable-dependent method assures systematic efficiency control of continuous flow collection procedures

BACKGROUND AND OBJECTIVES

Stem cell collection is a standard procedure for the procurement of autologous grafts to rescue myelosuppression induced by high-dose treatments. Accurate prediction of collection yields may contribute to optimize planning and quality control of collection.

MATERIALS AND METHODS

Data of 313 autologous haematopoietic stem cell (AHSC) evaluable collections performed in 208 patients with haematologic and non-haematologic neoplasms from seven centres were prospectively analysed to test the accuracy of yield predictions generated by a formula that required the input of peripheral blood (PB) CD34+ cell precount and desired PB volume to be processed. Data were matched in a standard linear regression, in a zero-point regression analysis and tested for prediction accuracy. Further 165 AHSC collections were analysed on a single-centre basis, using yield predictions as reference standards.

RESULTS

Analysis showed high levels of correlation between measured collection yields (my) and predictions (py) (R = 0.85; P = 0.000000) as well as high degree of prediction accuracy (my vs. py at paired t-test: P = 0.114781; median my/py ratio = 1.23). Analysis of additional 165 AHSC collections on a single-centre basis showed that the analysed centres had 70% or more measured yields comprising the 0.6-1.8 interval of the my/py ratio. The observance of the 'efficiency' my/py interval assured collection quality control in these centres confirming the reliability of the method.

CONCLUSIONS

This prediction method generates accurate and immediate yield predictions allowing collection planning and rapid efficiency control. As a consequence of our study, four centres out of seven use the described method to plan both leukapheresis number and single-procedure blood processing volume while the remaining three centres plan leukapheresis number on the basis of our predictions, maintaining a fixed single-procedure 200 ml/kg blood volume processing, according to their centre AHSC collection policy.

A comparison of ultrasonography and magnetic resonance imaging in the evaluation of temporomandibular joint involvement in rheumatoid arthritis and psoriatic arthritis

OBJECTIVE

To define the diagnostic value of ultrasonographic (US) examination in comparison with magnetic resonance imaging (MRI) for the assessment of temporomandibular joint (TMJ) involvement in rheumatoid arthritis (RA) and psoriatic arthritis (PsA).

METHODS

MRI and US examinations were performed in 33 patients (22 with RA and 11 with PsA). Alterations of the disc, alterations of the condyle and joint effusion were evaluated.

RESULTS

Pathological changes of the TMJ were observed by MRI in 24 patients and by US in 31 patients. The sensitivity and specificity of US were calculated in comparison with MRI. The sensitivity was 72.2% and the specificity was 60% in the assessment of pathological changes of the TMJ. The sensitivity was 69.6% with specificity of 30.0% in the assessment of alterations of the disc; the sensitivity was 70.6% with specificity of 75.0% in the assessment of joint effusion. Significant concordance was not observed in the assessment of condylar alterations.

CONCLUSIONS

US imaging appears able to detect different pathological changes of the TMJ and may be considered an important diagnostic tool for clinical evaluation of the TMJ in RA and PsA.

Role of the thyroid-stimulating hormone receptor signaling in development and differentiation of the thyroid gland

The thyroid-stimulating hormone/thyrotropin (TSH) is the most relevant hormone in the control of thyroid gland physiology in adulthood. TSH effects on the thyroid gland are mediated by the interaction with a specific TSH receptor (TSHR). We studied the role of TSHTSHR signaling on gland morphogenesis and differentiation in the mouse embryo using mouse lines deprived either of TSH (pit(dw)pit(dw)) or of a functional TSHR (tshr(hyt)tshr(hyt) and TSHR-knockout lines). The results reported here show that in the absence of either TSH or a functional TSHR, the thyroid gland develops to a normal size, whereas the expression of thyroperoxidase and the sodium/iodide symporter are reduced greatly. Conversely, no relevant changes are detected in the amounts of thyroglobulin and the thyroid-enriched transcription factors TTF-1, TTF-2, and Pax8. These data suggest that the major role of the TSH/TSHR pathway is in controlling genes involved in iodide metabolism such as sodium/iodide symporter and thyroperoxidase. Furthermore, our data indicate that in embryonic life TSH does not play an equivalent role in controlling gland growth as in the adult thyroid.

The concept of pain in the 17th century

The 17th century is very important in the history of sensation and pain. Philosophers, as Descartes, Hobbes, Spinoza, defined a new philosophy of science. Physicians of the iatro-chemical school introduced the first principles of biochemistry, tied to the sensations. Physicians of the iatro-mechanical school postulated a really modern concept: the importance of nerve juices in sensibility and pain.

The mycotoxin ochratoxin A alters intestinal barrier and absorption functions but has no effect on chloride secretion

Ochratoxin A (OTA) is a mycotoxin that contaminates cereals and animal feed and causes nephropathy to a variety of animal species. OTA is also known as a potent immunotoxic, teratogenic, and carcinogenic mycotoxin. In addition, OTA ingestion induces intestinal injuries, including inflammation and diarrhea. With the aim to study the cellular mechanisms associated with the intestinal toxicity of OTA, two human epithelial intestinal cell lines (HT-29-D4 and Caco-2-14 cells), widely used as in vitro models for the intestinal epithelium, were incubated with OTA. The main effects of the mycotoxin were an inhibition of cellular growth and a dramatic decrease of transepithelial resistance in both cell lines. Since transepithelial resistance reflects the organization of tight junctions over the cell monolayer, these data may suggest that OTA could potentiate its own absorption through paracellular pathways. OTA induced a 60% decrease of sodium-dependent glucose absorption but increased the absorption of fructose and L-serine in HT-29-D4 cells. Moreover, the mycotoxin did not inhibit the cAMP-dependent chloride secretion through the cystic fibrosis transmembrane conductance regulator channel. The inhibitory effect of OTA on active glucose transport was partially antagonized by L-phenylalanine, but not by alpha-tocopherol, suggesting that the toxicity of OTA could result from an inhibition of protein synthesis, rather than an induction of lipid peroxidation. In particular, OTA affected the protein content of plasma membrane microdomains, which are known to regulate tight junction assembly and intestinal transport activity. Taken together, these data showed that OTA alters both barrier and absorption functions of the intestinal epithelium.

Glycosphingolipid (GSL) microdomains as attachment platforms for host pathogens and their toxins on intestinal epithelial cells: activation of signal transduction pathways and perturbations of intestinal absorption and secretion

Glycosphingolipid (GSL)-enriched microdomains are used as cellular binding sites for various pathogens including viruses and bacteria. These attachment platforms are specifically associated with transducer molecules, so that the binding of host pathogens (or their toxins) to the cell surface may result in the activation of signal transduction pathways. In the intestinal epithelium, such pathogen-induced dysregulations of signal transduction can elicit a severe impairment of enterocytic functions. In this study, we demonstrate that the interaction of a bacterial toxin (cholera toxin) and a viral envelope glycoprotein (HIV-1 gp120) with the apical plasma membrane of intestinal cells is mediated by GSL-enriched microdomains that are associated with G regulatory proteins. These microbial proteins induce a GSL-dependent increase of intestinal fluid secretion by two mechanisms: activation of chloride secretion and inhibition of Na+ -dependent glucose absorption. Taken together, these data support the view that GSL-enriched microdomains in the apical plasma membrane of enterocytes are involved in the regulation of intestinal functions.

Human erythrocyte glycosphingolipids as alternative cofactors for human immunodeficiency virus type 1 (HIV-1) entry: evidence for CD4-induced interactions between HIV-1 gp120 and reconstituted membrane microdomains of glycosphingolipids (Gb3 and GM3)

Glycosphingolipids from human erythrocytes mediate CD4-dependent fusion with cells expressing human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins. To identify the glycosphingolipid(s) which participates in the fusion process, we have analyzed the interaction of HIV-1 gp120 (X4 and R5X4 isolates) with reconstituted membrane microdomains of human erythrocyte glycosphingolipids. We identified globotriaosylceramide (Gb3) and ganglioside GM3 as the main glycosphingolipids recognized by gp120. In the presence of CD4, Gb3 interacted preferentially with the X4 gp120, whereas GM3 interacted exclusively with the R5X4 gp120. These data suggest that glycosphingolipid microdomains are required in CD4-dependent fusion and that Gb3 and/or GM3 may function as alternative entry cofactors for selected HIV-1 isolates.

Surgical laparoscopy with intraoperative manometry in the treatment of esophageal achalasia

The aim of this study was to describe and evaluate the laparoscopic treatment of esophageal achalasia in nine patients over a 35-month period. Five trocars were used to perform a Heller's myotomy to completely eliminate the cardial high-pressure zone, under manometric control. Intraoperative manometry also was used to calibrate a pick degrees 360 Rossetti's antireflux wrap. A complete regression of symptoms was observed postoperatively in seven of nine patients (77.8%); in two patients (22.2%) a moderate dysphagia persisted, but it disappeared 3 and 6 months, respectively. Only one intraoperative complication (esophageal perforation, recognized and laparoscopically repaired) occurred. At the present follow-up of 18 +/- 5.34 months (range 6-35), no dysphagia or symptoms related to reflux have been observed. Laparoscopic treatment of esophageal achalasia is considered a safe and effective procedure, and the results of this procedure are comparable with those of the open technique. Advantages common to other laparoscopic techniques are emphasized.

Substance P in the serum of patients with rheumatoid arthritis

Serum substance P was assayed in rheumatoid arthritis patients and healthy controls to evaluate whether neurogenic inflammation with substance P release is significant in rheumatoid arthritis. A very sensitive competitive immunoenzymetric assay was used. Mean serum substance P level was significantly higher in rheumatoid arthritis patients than in controls and was not correlated with disease duration, morning stiffness duration, Thompson's articular index, Larsen's radiographic score, or the following laboratory indices of inflammation: erythrocyte sedimentation rate, C-reactive protein, and alpha 1-acid glycoprotein. Neurogenic inflammation with substance P release may contribute significantly to the pathogenesis of rheumatoid arthritis. The absence of correlations between serum substance P and clinical or laboratory indices of inflammation may reflect complex interactions between neurogenic inflammation and other pathogenic mechanisms, which may influence clinical features and laboratory tests in rheumatoid arthritis patients.

Osteopontin-hydroxyapatite interactions in vitro: inhibition of hydroxyapatite formation and growth in a gelatin-gel

Osteopontin is a phosphorylated bone matrix sialoprotein, postulated to play a regulatory role in biomineralization. The effects of a crude preparation of rat bone osteopontin and a more highly purified bovine bone osteopontin were evaluated using a gel diffusion system to measure effects of 0.1-100 micrograms/ml of this matrix protein on hydroxyapatite formation and crystal proliferation. Bovine osteopontin at concentrations greater than 25 micrograms/ml inhibited both hydroxyapatite formation and growth in a dose-dependent manner. Osteopontin at concentrations lower than 25 micrograms/ml had no detectable effect on the amount of mineral accumulated in experiments with and without pre-formed hydroxyapatite seed crystals either when initial mineral deposition was assessed at 3.5 days, or when mineral formation and growth were assessed at 5 days. There was a statistically significant dose-dependent decrease in crystal length at all concentrations tested. The rat osteopontin preparation had similar inhibitory abilities. Partial dephosphorylation of bovine osteopontin with alkaline phosphatase removed its inhibitory ability, and reduced its ability to bind calcium. The affinity of bovine osteopontin for hydroxyapatite was determined based on a Langmuir adsorption isotherm, with values of K (binding affinity) and N (number of binding sites) being 0.026 ml/microgram and 1084 micrograms/m2, respectively. The data suggest that, in this system, osteopontin is an effective inhibitor of hydroxyapatite formation and growth due to its affinity for the hydroxyapatite crystals. In this system, osteopontin, distinct from other phosphoproteins which both promote and inhibit hydroxyapatite deposition, did not enhance mineral formation at any concentration tested.

p-Bromophenacyl bromide potentiates hydrogen peroxide formation in human platelets challenged by thrombin and inhibits aggregation

p-Bromophenacyl bromide, a potent alkylating agent inhibitor of phospholipase A2 and adenylate cyclase, potentiates hydrogen peroxide production in human platelets activated with thrombin. The maximal cooperative effect, specific for thrombin as inducer and potentiated by exogenous calcium, was observed at 2 microM BPB. Since it was shown that BPB is also a strong inhibitor of platelet aggregation (IC 50 = 3 +/- 1 microM) it is likely to suppose that the abnormal accumulation of hydrogen peroxide can influence platelet function.

Cytoskeleton protein composition upon platelet stimulation with thrombin in essential thrombocythemia

BACKGROUND

Structural and functional platelet alterations are present in essential thrombocythemia (E.T.). Platelet aggregation patterns are highly variable; moreover, structural, biochemical and metabolic platelet defects have also been shown. In this study, data on function and structure of platelets from a group of patients affected with E.T. are reported. Since cytoskeleton proteins are involved in activation and aggregation mechanisms, we investigated the cytoskeleton protein composition of resting, activated and aggregated platelets using electrophoretic analysis.

PATIENTS AND METHODS

Studies were performed on 13 patients affected with E.T. On the basis of their functional behavior in response to thrombin, patients were divided into two groups: T1 (5 patients) and T2 (8 patients). A group of 11 healthy subjects was examined as control. Washed platelets were stimulated with 0.05 or 0.25 U/mL thrombin in the presence or the absence of EGTA in order to obtain activated or aggregated platelets. Triton-insoluble residues of activated and aggregated platelets were electrophoresed on 4.5-15% linear gradient SDS polyacrylamide gel, visualized by Coomassie blue stain and scanned with a densitometer.

RESULTS

On the basis of the response to thrombin, group T1 was composed of subjects showing completely normal functional behaviour, while group T2 included patients who were more active than controls in response to low thrombin concentrations. By comparing the densitometric data of the two groups of patients it is possible to show that cytoskeleton structures in the T2 group have a significantly higher protein content than normals and than group T1. Platelet treatment with high thrombin concentrations cancels every difference between the two groups of patients with the exceptions of a 33-Kd protein and actin, which remain higher in group T2.

CONCLUSION

Abnormal platelet function and quantitative cytoskeleton protein content can be correlated in patients affected with E.T. In the platelets of those patients who display higher responsiveness to thrombin, either altered calcium homeostasis or changes in membrane viscosity leading to altered thrombin receptor expression, or both these events, could be present.

Generation of hydrogen peroxide in resting and activated platelets

The production of hydrogen peroxide was measured by following the oxidation of dichlorofluorescein (DCFH) entrapped into platelets. Resting platelets produced nanomolar quantities of DCF, which was proportional to the concentration of platelets and was steady during 1 h of incubation. A significant increase of basal DCF fluorescence was induced by stimuli namely thrombin, arachidonic acid, the Ca2+ ionophore A23187 and PMA. The effect of agonists has been also measured in the presence of 3-amino-1,2,4-triazole (AT) or N-ethylmaleimide (NEM), inhibitors of catalase and glutathione peroxidase, respectively. A further significant enhancement of DCF produced in stimulated platelets was detected only in the presence of NEM. A correlation was found between the increase in DCF and externally added hydrogen peroxide or the oxidizing species formed by xanthine oxidase plus acetaldehyde. The yield was not affected by superoxide dismutase and was higher in the presence of AT or NEM. A cooperative effect in the presence of both inhibitors was shown. Glutathione peroxidase plus glutathione diminished the level of DCF to basal levels.

Increased hydrogen peroxide formation in platelets of patients affected with essential thrombocythaemia (ET)

The basal platelet level of reactive oxygen species and their enhancement following stimulation by different agonists were determined in a selected group of patients with essential thrombocythaemia (ET). Activated platelets had lower levels of superoxide anion and higher intracellular concentrations of hydrogen peroxide than controls. Higher levels of lipid peroxidation induced by N-ethylmaleimide were also observed. Measurement of the most important enzymes generating and scavenging these reactive oxygen species revealed increased specific activities of NADPH-cytochrome c reductase and superoxide dismutase and a decrease in platelet catalase activity in patients with ET. Since an abnormal production of oxygen radicals seems to be implicated in various pathological conditions and aging processes, the increased amount of hydrogen peroxide found in platelets of patients could be involved in some of the platelet alterations described in ET.

Treatment of proteoglycan aggregates with physeal enzymes reduces their ability to inhibit hydroxyapatite proliferation in a gelatin gel

In vitro, cartilage proteoglycans (PGs) are effective inhibitors of hydroxyapatite formation and growth. Their inhibitory ability decreases with decreasing PG size and charge density. It has been suggested that the enzyme-mediated alteration in the size and conformation of PGs in the growth plate may similarly facilitate the calcification process. In this study, a gelatin gel system was used to monitor hydroxyapatite formation and growth in the presence of proteoglycan aggregates, before and after enzyme treatment. To reproduce the physeal degradation cascade, an enzyme preparation was used that contained all of the growth plate enzymes. At a concentration of 500 micrograms/ml, the untreated proteoglycan aggregates reduced the amount of mineral formed by 30%. When the aggregates were treated with the heat-inactivated enzyme, the same extent of inhibition was found. In contrast, treating the aggregates with the crude growth plate enzyme preparation removed all the inhibitory ability, such that 500 micrograms/ml of proteoglycan preparation yielded 10% more mineral than the controls. Treatment of the aggregates with chondroitinase ABC and trypsin, similarly removed all the inhibitory ability. These data, suggest that enzymatic degradation of proteoglycans may contribute to the regulation of growth plate calcification.

Hydroxyapatite formation in the presence of proteoglycans of reduced sulfate content: studies in the brachymorphic mouse

Proteoglycans from the brachymorphic (bm/bm) mouse have a reduced sulfate content due to the impaired activity of adenosine phosphosulfate phosphokinase in these animals. X-ray diffraction and infrared analyses of the mineral from the calcified cartilage of the bm/bm mice demonstrate the presence of significantly larger and more perfect hydroxyapatite crystals of lower carbonate to phosphate content than crystals found in the control animals. No differences were seen in the mineral content, crystallite size, CO3:PO4 ratio, or infrared splitting factors measured in the diaphyseal bone from these animals. Electron microscopic examination similarly shows larger, more disorganized crystals in the bm/bm animals' calcified cartilage as contrasted with controls. In vitro, proteoglycan aggregates from these dwarf mice are shown in a collagen gel-growth system to be less effective inhibitors of hydroxyapatite formation and growth than similarly size sulfated proteoglycans from age-matched control animals. The proteoglycans from the control mice were comparable in inhibitory ability to proteoglycan aggregates extracted from fetal bovine epiphyses. The in vitro and in vivo mineral parameters suggest the importance of sulfate for the interaction between proteoglycans and mineral in growth plate calcification.

Oxidative metabolism of human platelets

The reducing capacity toward cytochrome c present in human resting platelets increases upon platelet stimulation, and is partially inhibited by superoxide dismutase. This activity therefore represents the generation of superoxide anion. In order to evaluate hydrogen peroxide formation a quantitative assay by mean of dichlorofluorescin (DCFH) has been set up. The DCFH, trapped inside the cell, is oxidized by hydrogen peroxide to the fluorescent compound DCF. Basal DCF increases during activation of platelets by agonists. Arachidonic acid, calcium ionophore A23187 and to a lesser extent PMA and thrombin are the most effective. N-ethylmaleimide induces a dose-dependent DCFH oxidation and potentiates the effect of agonists. NAD(P)H--cytochrome c reductase enzyme, which catalyzes superoxide anion production, is present in platelets at high specific activity, as well as those enzymes who protect the cells from oxygen reactive species.

Mode of action of 2-(diethylamino)-7-ethoxychromone on human platelets

The in vitro effect of 2-(diethylamino)-7-ethoxychromone (RC39XVIII) on human platelet aggregation induced by several agonists and on thromboxane B2 formation, granule release and intracellular cAMP elevation has been studied. The chromosome-derivative exerts a dose-dependent inhibitory effect on aggregation produced by U46619, arachidonic acid, thrombin, collagen and ADP. RC39XVIII inhibits aggregation, TxB2 formation and granule release in parallel. Moreover the drug potentiates cAMP accumulation induced by iloprost and forskolin. The drug also inhibits soluble cAMP phosphodiesterase in a dose-dependent manner. No effect on adenylate cyclase activity measured in platelet membranes was evident.

Antiplatelet effect of 2-(diethylamino)-7-hydroxychromone

In this study the in vitro influence of 2-(diethylamino)-7-hydroxychromone (RC39II) on platelet aggregating responses, thromboxane A2 (TxA2) production, release reaction and intraplatelet cyclic AMP (cAMP) content has been investigated. The drug exerts a dose-dependent inhibitory effect on aggregating response to arachidonic acid, U46619, thrombin, collagen and calcium ionophore A23187. Inhibiting concentrations of RC39II also prevent platelet release reaction and TxA2 formation. RC39II potentiates platelet cAMP accumulation by Iloprost. Several studies, carried out on soluble cAMP phosphodiesterase (PDE) have shown that the drug inhibits phosphodiesterase in a dose-dependent manner. No effect was shown on adenylate cyclase activity from platelet membranes.

Concentration-dependent effects of dentin phosphophoryn in the regulation of in vitro hydroxyapatite formation and growth

The effect of dentin phosphophoryn on hydroxyapatite formation and growth was studied in an in vitro gelatin gel diffusion system. Phosphophoryn, in low concentrations (0.010-1 microgram/ml) promoted de novo hydroxyapatite formation; at a higher concentration (100 micrograms/ml) in the same system, the dentin matrix protein inhibited hydroxyapatite growth. Similar inhibition of hydroxyapatite growth was seen in solution. The intact phosphophoryn was not essential for either inhibition of seeded growth or promotion of mineralization, since the formic acid degraded protein was comparably effective. Transmission electron microscopy of the precipitates formed at 7 days showed no significant differences in crystallite size distribution in the presence and absence of phosphophoryn. However there was a dose-dependent decrease in the number of mineral clusters formed in the presence of increasing amounts of phosphophoryn, suggesting inhibition of secondary nucleation. These data provide support for the postulated 'multifunctional' role of the dentin phosphoprotein in the mineralization process.

Platelets of patients affected with essential thrombocythemia are abnormal in plasma membrane and adenine nucleotide content

The adenine nucleotides present in distinct cellular compartments of platelets of 27 patients affected with essential thrombocythemia have been measured. In order to quantify granule-bound nucleotides and adenylic cytoplasmic pool, platelets have been stimulated with thrombin or treated with increasing digitonin concentrations, respectively. Among patients, we have identified two groups: 12 patients (Group 1) had normal platelet level of ATP and ADP both in dense granules as well as in cytoplasmic pool. The other patients (Group 2) had granule ATP and ADP significantly lower and ATP/ADP ratio significantly higher than controls. In these patients an increase in hypoxanthine level, derived from metabolic ATP degradation occurring during stimulation, was observed. In addition, in the latter patients an increased resistance of plasma membrane to digitonin was shown, suggesting that membrane fluidity should be reduced owing to a modified cholesterol/phospholipid ratio.

Protein composition in resting and activated platelets of type I diabetic patients

Protein composition of platelets of eleven type I diabetic patients and thirteen control subjects were analyzed by SDS polyacrylamide gel electrophoresis. Bands have been scanned and quantified. No significant difference was shown between controls and patients in any of the bands identified in electrophoretic patterns of whole platelet, membrane fraction, resting, activated and aggregated cytoskeleton. Data suggest that alterations observed in platelet function of diabetic patients cannot be connected to the changes in protein composition.

Clinical aspects of visceral pain

Pain producing stimuli in viscera are different from the stimuli which induce somatic pain. Two main clinical aspects of visceral pain are observed: true visceral pain and referred pain. The distinction among visceral pain, referred pain and somatic pain may be difficult in the so-called "intricate conditions". Furthermore, mnemonic traces may play an important role in determining clinical aspects of visceral pain.

The effects of noncollagenous matrix proteins on hydroxyapatite formation and proliferation in a collagen gel system

The effects of several noncollagenous matrix proteins on hydroxyapatite formation and growth were studied in a dynamic collagen gel system. In this system growth plate proteoglycan aggregates at concentrations of 1-10 micrograms/ml were effective inhibitors, desulfated aggregates from brachymorphic mice were less effective. Phosphophoryn at 1-100 micrograms/ml had no effect on formation; 60-120 micrograms/ml retarded mineral growth. Type X collagen at concentrations of 50-300 micrograms/ml had no effect on formation or growth.

Inhibition of the glycolytic pathway by methylglyoxal in human platelets

The incubation of human platelets with methylglyoxal and glucose produces a rapid transformation of the ketoaldehyde to D-lactate by the glyoxalase system and a partial reduction in GSH. Glucose utilization is affected at the level of the glycolytic pathway. No effect of the ketoaldehyde on glycogenolysis and glucose oxidation through the hexose monophosphate shunt was demonstrated. Phosphofructokinase, fructose 1,6 diphosphate (F1, 6DP) aldolase, glyceraldehyde 3-phosphate dehydrogenase and 3-phosphoglycerate mutase were mostly inhibited by methylglyoxal. A decrease in lactate and pyruvate formation and an accumulation of some glycolytic intermediates (fructose 1,6 diphosphate, dihydroxyacetone phosphate, 3-phosphoglycerate) was observed. Moreover methylglyoxal induced a fall in the metabolic ATP concentration. Since methylglyoxal is an intermediate of the glycolytic bypass system from dihydroxyacetone phosphate to D-lactate, it may be assumed that ketoaldehyde exerts a regulating effect on triose metabolism.

Alkaline extraction and reverse-phase high-performance liquid chromatography of adenine and pyridine nucleotides in human platelets

The levels of adenine (ATP, ADP, AMP) and pyridine (NAD, NADH) nucleotides in human platelets have been measured by a simple and reproducible method. A rapid alkaline extraction allows a complete recovery of the compounds concerned. The metabolic ATP and ADP in the cytosolic fraction, the amount released upon thrombin stimulation, and the ADP bound to F-actin have also been evaluated. Analysis was performed by reverse-phase, isocratic high-performance liquid chromatography on a 5-microns Lichrosorb RP-18 column with uv detection at 254 nm.

Platelet glucose metabolism in type I diabetic subjects

In a group of 35 type I diabetics, platelet glycolytic and glycogenolytic flux have been measured. In type I diabetic platelets glucose uptake was significantly reduced. The quite normal lactate production was obtained by a faster utilization of stored glycogen in these patients. Specific activity of glycolytic enzymes was normal, in particular the levels and kinetic properties of soluble and membrane bound hexokinase. The rate of glucose flux through the hexose monophosphate shunt, measured either in resting or in arachidonic acid-stimulated platelets, was normal in diabetics. Kinetics of glucose transport across plasma membrane have also been determined. Km was significantly increased in diabetic patients. No changes was shown in Vmax. Modifications present in membrane organization of patients could involve glucose transport protein.