Exploring the short linear motif-mediated protein-protein interactions of CrkL through ProP-PD

Adaptor proteins play a pivotal role in cellular signaling mediating a multitude of protein-protein interaction critical for cellular homeostasis. Dysregulation of these interactions has been linked to the onset of various cancer pathologies and exploited by viral pathogens during host cell takeover. CrkL is an adaptor protein composed of an N-terminal SH2 domain followed by two SH3 domains that mediate interactions with diverse partners through the recognition of specific binding motifs. In this study, we employed proteomic peptide-phage display (ProP-PD) to comprehensively explore the short linear motif (SLiM)-based interactions of CrkL. Furthermore, we scrutinized how the binding affinity for selected peptides was influenced in the context of the full-length CrkL versus the isolated N-SH3 domain. Importantly, our results provided insights into SLiM-binding sites within previously reported interactors, as well as revealing novel human and viral ligands, expanding our understanding of the interactions mediated by CrkL and highlighting the significance of SLiM-based interactions in mediating adaptor protein function, with implications for cancer and viral pathologies.

ABCB1 c.-6-180T>G polymorphism and clinical risk factors in a multi-breed cohort of dogs with refractory idiopathic epilepsy

Epilepsy is the most common chronic neurological disorder in dogs. Approximately 20-30% of dogs do not achieve satisfactory seizure control with two or more anti-epileptic drugs at appropriate dosages. This condition, defined as refractory epilepsy, is a multifactorial condition involving both acquired and genetic factors. The P glycoprotein might play and important role in the pathophysiological mechanism and it is encoded by the ABCB1 gene. An association between a single nucleotide variation of the ABCB1 gene (c.-6-180T>G) and phenobarbital resistance has previously been reported in a Border collie population with idiopathic epilepsy. To date, the presence and relevance of this polymorphism has not been assessed in other breeds. A multicentre retrospective, case-control study was conducted to investigate associations between ABCB1 c.-6-180T>G, clinical variables, and refractoriness in a multi-breed population of dogs with refractory idiopathic epilepsy. A secondary aim was to evaluate the possible involvement of the ABCB1 c.-6-180T>G single nucleotide variation this population. Fifty-two refractory and 50 responsive dogs with idiopathic epilepsy were enrolled. Of these, 45 refractory and 50 responsive (control) dogs were genotyped. The G allele was found in several breeds, but there was no evidence of association with refractoriness (P=0.69). The uncertain role of the c.-6-180T>G variation was further suggested by an association between the T/T genotype with both refractoriness and responsiveness in different breeds. Furthermore, high seizure density (cluster seizure) was the main clinical risk factor for refractory idiopathic epilepsy (P=0.003).

Concurrent chemoradiation (CCR) for locally advanced or relapsed vulvar carcinoma (VC) treatment: An alternative to pelvic exenteration (PE)

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Background: PE is the standard treatment for locally advanced or relapsed VC that involves the anus or rectovaginal wall, with high morbidity and the consequent loss of Qol. Objective: Locoregional response, toxicity, disease free survival (DFS) and survival (SV) achieved with concurrent chemoradiation in locally advanced or relapsed VC was prospectively evaluated. Methods: From 7/93 to 05/05, 32 pts which would have required some kind of PE were treated with mitomycin C (10 mg./m2 d1) + 5-Fluoruracil (800 mg/m2 d 1–4) IV continuous infusion, plus concurrent external radiotherapy (50 Gy) to the vulva, pelvis and groin. An additional boost (15–20 Gy) was added when a less than complete clinical response (CR) was achieved. Multiple biopsies of the tumor bed were performed to confirm complete pathologic responses (CPR). Results: 30 pts (94%) completed treatment as planned. Overall, locoregional response was obtained in 25/30 (83.3%) pts: 20 (66.6%) CR, 5 (16.6%) partial response (PR). 3 (10%) pts had stable disease and 2 (6.6%) progresive disease. 14/30 (46.6%) had CPR. Radical vulvectomy or radical local excision was performed in 7 pts for residual disease after CCR (4/6 with CR and microscopic residual disease and 3/5 with PR), 2 pts with PR were lost after having completed CCR and 2 pts with CR and microscopic residual disease refused further treatment. None of the responding patients required PE. Treatment was well tolerated with mild to moderate toxicity, attributed to radiotherapy. No treatment deaths were recorded. 28 pts with a median follow-up of 25.5 months (range 6–126) showed a 5-year cumulative DFS (34%) and SV (49%). Conclusion: CCR is a safe therapeutic option with results comparable to those obtained with PE, with significant improvement of Qol. CCR has become the standard treatment for locally advanced or relapsed VC at our center.

No significant financial relationships to disclose.

A double-blind randomized placebo-controlled trial with short-term beta-glucuronidase therapy in children with chronic rhinoconjunctivitis and/or asthma due to dust mite allergy

BACKGROUND

Enzyme potentiated desensitization, in which beta-glucuronidase (BG) is administered with low doses of mixed allergens, was proposed in the 1970s for specific immunotherapy. The BG currently commercially available in a purified and standardized preparation devoid of any allergen has been suggested as a regulator in the allergic immune response, acting on the cytokine-network of type 2 helper T cells. A double-blind trial with a single-dose of BG proved effective in preventing symptoms in adult patients with rhinoconjunctivitis due to grass pollens.

OBJECTIVE

The aim of this randomized double-blind placebo-controlled trial was to confirm the safety and effectiveness of double-dose intradermal BG immunotherapy in preventing symptoms in children suffering from chronic rhinoconjunctivitis and/or asthma due to dust mite.

METHOD

We randomized 125 children with dust-mite related chronic rhinoconjunctivitis and/or asthma to the BG treated group (67) or the placebo group (58). All patients were screened before treatment (TO), at BG or placebo administration (T1 and T3), and at 3 and 9 months after T1 (T2 and T4). Drug intake and bronchial, nasal and ocular symptoms were recorded in a diary.

RESULTS

Patients in both groups completed the study and BG treatment was well tolerated without side effects. Significant differences in symptoms were observed, in particular for conjunctivitis (P= .008). The total drug intake for allergic symptoms was significantly lower in the treated group than in the placebo group (P<. 01).

CONCLUSIONS

BG immunotherapy is efficacious, safe, and well tolerated in allergic children. Moreover, good compliance with the administration of 2 doses per year and the lack of significant side effects makes the benefit/risk ratio of this treatment particularly favorable.

Tumour staging, morphology and p53 overexpression concur in predicting survival in hepatocellular carcinoma

BACKGROUND/AIMS

The prognosis of hepatocellular carcinoma (HCC) on cirrhosis is hard to predict as it depends on tumour stage, underlying liver disease, type of treatment and, possibly, biological factors of the tumour itself.

METHODS

We prospectively evaluated the survival of 91 consecutive patients with HCC on cirrhosis, diagnosed between January 1998 and December 1999. Clinical features and histological/biological aspects, including histotype, grade, p53 overexpression, cytoproliferation and apoptotic markers were analysed.

RESULTS

Child-Pugh (P = 0.01), Okuda (P < 0.0001), Cancer of the Liver Italian Program (CLIP) staging (P < 0.0001) and type of treatment (P = 0.0001) were significantly related to survival. In the Cox model, CLIP staging was included as independent predictor of survival at step 1 (P < 0.0001) with Okuda at step 2 (P = 0.013). Amongst the biological factors, p53 overexpression and histotype were significantly related with survival (P = 0.0044 and 0.017 respectively). When clinical and biological variables were examined together in the Cox model, CLIP and Okuda were confirmed as being statistically related with survival (P < 0.0001 and =0.012) followed by histotype and p53 overexpression (P = 0.019 and 0.02).

CONCLUSIONS

CLIP, Okuda, histotype and p53 overexpression are the strongest predictors of survival in this series of patients. These data confirm that staging of the tumour and underlying liver disease are strictly related to prognosis but support the concurrent role of clinical and biological factors in upgrading our capacity of predicting the fate of HCC patients.

[Comparison of methodologies to reach 'dry weight']

BACKGROUND

In clinical practice it is very difficult to determine a final weight that is the expression of normovolemia. In hemodialysis (HD), 'dry weight' is conventionally defined as the weight reached by the patient at the end of that hemodialytic session when the maximum quantity of fluids is removed without inducing any symptomatology. The determination of dry weight has been based on the application of clinical criteria. The use of artificial kidneys with blood volume (BV) sensors has allowed the determination of dry weight through the interpretation of changes in the intradialytic BV curve. Conventional bioimpedance analysis (BIA), or better, the vectorial BIA (BIVA) is a new method for determining dry weight. This study evaluated the use of the above-mentioned method for the proper governing of dry weight.

PATIENTS AND METHODS

Twenty HD patients were observed for 4 weeks. In the 1st week, the clinical symptomatology of every patient was monitored during both HD sessions and interdialytic periods. During the 2nd week, intradialytic changes in the BV of each patient were observed on artificial kidneys. In the 3rd week, a cardiologist monitored patients before and after hemodialytic treatments. In the 4th week, the body composition of each patient was analyzed through bioelectrical bioimpedance.

RESULTS

Patients, who had clinically shown symptoms of hyperhydration, to the contrary at BIA were dehydrated. Conversely, patients who had dehydration symptoms presented signs of hyperhydration at BIA.

CONCLUSIONS

BIVA is the diagnostic instrument that more accurately demonstrates the hydration state of hemodialytic patients. It contributes in defining dry weight more efficiently.

Liver transplantation: the Italian experience

BACKGROUND

Liver transplantation is the standard treatment for patients with end-stage liver disease no longer responsive to conventional medical treatment

AIMS

To report the long-term experience of liver transplantation in Italy.

PATIENTS AND METHODS

Data were obtained retrospectively by means of a multiple-item form collected from 15 Italian liver transplant centres. The filing centre was centralized.

RESULTS

A total of 3323 liver transplants were performed on 3026 patients, with a cumulative proportional survival of 72.4%. Three, 5 and 10 years' patient survival rates were 72.3%, 68.8% and 61.3%, respectively. The most common indication for liver transplantation were hepatitis B virus (+/- hepatitis D virus)- and hepatitis C virus-related cirrhosis (59.4%). Excellent survival rates were observed particularly in controversial indications, such as alcoholic cirrhosis, hepatitis B virus-related cirrhosis and hepatocellular carcinoma. Retransplantation was required in 8.9% of the cases. The overall prevalence of acute cellular rejection episodes was 43.5%. In our study population, primary non-function and disease recurrence were the most common causes of graft failure (28.7% and 25.4%, respectively). Infections and/or sepsis were the most common causes of death after transplantation (42%).

CONCLUSION

This study confirms that patients with controversial indications to liver transplantation such as alcoholic cirrhosis, HBV-related cirrhosis and hepatocellular carcinoma can achieve excellent survival when properly selected.

Fast coordination changes in cytochrome c do not necessarily imply folding

Folding of globular proteins occurs with rates that range from microseconds to minutes; consequently, it has been necessary to develop new strategies to follow the faster processes that exceed stopped-flow capabilities. Rapid photochemical methods have been employed to study the rate of folding of reduced cytochrome c. In this protein, the iron of the covalently bound heme binds a His and a Met, proximal and distal. Unfolding by guanidine or urea weakens the Fe-Met bond, and the reduced unfolded cytochrome c easily binds CO and other heme ligands, which would react slowly or not at all with the native protein. Therefore in the presence of CO, reduced cytochrome c unfolds at lower denaturant concentrations than in the absence of this ligand, and rapid photochemical removal of CO from unfolded cytochrome c, is expected to trigger at least an incomplete refolding. This approach is complicated by the breakage of the proximal His-Fe bond that may occur as a consequence of CO photodissociation in the unfolded cytochrome c because of the so-called base elimination mechanism. Rebinding of CO to the four-coordinate heme yields kinetic intermediates unrelated to folding. Our hypothesis is supported by parallel observations carried out with protoheme and microperoxidase.

Does the choice of treatment influence survival of patients with small hepatocellular carcinoma in compensated cirrhosis?

OBJECTIVE

Untreated patients with small, single hepatocellular carcinoma (HCC) in compensated cirrhosis are characterized by a relatively good prognosis.

METHODS

We report the findings generated in a retrospective study on a cohort of 186 consecutive patients with small (< 5 cm) HCC in Child A or B cirrhosis, who were transplanted (four), underwent surgery (15), or were treated with percutaneous ethanol injection (117), lipiodol chemoembolization (44) or best supportive care (six), depending on their clinical features.

RESULTS

Overall survival was 26% at 5 years (31% Child A, 20% Child B), with a mean and median survival of 44 and 38 months, respectively. The longest survival was obtained with transplantation and surgery, and the worst with best supportive care. When untreated patients were not considered, no significant differences were observed between the different types of treatment, however, even when patients in the Child A group were considered alone. Almost all the patients who underwent surgery relapsed. No significant difference was observed in relation to the stage of the disease, while alpha-fetoprotein levels were singled out as the only relevant prognostic factor in a multivariate Cox's regression model. Costs per year of life saved were extremely high for transplantation and lowest for ethanol injection, with surgery being less expensive than chemoembolization.

CONCLUSIONS

This study confirms that patients with single, small HCC nodules in well compensated cirrhosis should be treated. The choice of type of treatment should be based on the availability of local resources and expertise, and on the patients' preference, after they have been properly informed on the survival, morbidity and mortality related to each treatment option. The relative cost of the procedures should also be considered.

Refolding kinetics of cytochrome c(551) reveals a mechanistic difference between urea and guanidine

The energetic parameters for the folding of small globular proteins can be very different if derived from guanidine hydrochloride (GdnHCl) or urea denaturation experiments. A study of the equilibrium and kinetics of the refolding of wild-type (wt) cytochrome c(551) (cyt c(551)) from Pseudomonas aeruginosa and of two site-directed mutants (E70Q and E70V) shows that the nonionic nature of urea reveals the role of a salt bridge between residues E70 and K10 on the transition state, which is otherwise completely masked in GdnHCl experiments. Mixed denaturant refolding experiments allow us to conclude that the masking effect of GdnHCl is complete at fairly low GdnHCl concentrations ( congruent with 0.1 M). The fact that potassium chloride is unable to reproduce this quenching effect, together with the results obtained on the mutants, suggests a specific binding of the Gdn(+) cation, which involves the E70-K10 ion pair in wt cyt c(551). We propose, therefore, a simple kinetic test to obtain a mechanistic interpretation of nonlinear dependences of DeltaG(w) on GdnHCl concentration on the basis of kinetic refolding experiments in the presence of both denaturants.

Snapshots of protein folding. A study on the multiple transition state pathway of cytochrome c(551) from Pseudomonas aeruginosa

Cytochrome c(551) (cyt c(551)) from Pseudomonas aeruginosa is a small protein (82 residues) that folds via a three-state pathway with the accumulation in the microsecond time-range of a compact collapsed intermediate. The presence of a single His residue, at position 16, permits the study of the refolding at pH 7.0 in the absence of miscoordination events. Here, we report on folding kinetics in the millisecond time-range as a function of urea under different pH conditions. Analysis of this process (over-and-above proline cis-trans isomerization) at pH 7.0, suggests the existence of a multiple transition state pathway in which we postulate three transition states. Taking advantage of site-directed mutagenesis we propose that the first "unfolded-like" transition state (t(1)) originates from the electrostatic properties of the collapsed state, while the second transition state (t(2)) involves the interaction between the N and C-terminal helices and is stabilized by the salt bridge between Lys10 and Glu70 ( approximately 1 kcal mol(-1)). Our results suggest that, contrary to other cytochromes c, the roll-over effect observed for cyt c(551) at low denaturant concentration can be interpreted in terms of a broad energy barrier without population of any intermediates. The third and more "native-like" transition state (M) can be associated with the breaking/formation of the Fe(3+)-Met61 bond. This strong interaction is stabilized by the hydrogen bond between Trp56 and heme propionate 17 (HP-17) as suggested by the increase in the unfolding rate at high denaturant concentration of the Trp56Phe site-directed mutant.

How should patients with hepatocellular carcinoma be staged? Validation of a new prognostic system

BACKGROUND

The life expectancy of a patient with hepatocellular carcinoma (HCC) in cirrhosis is hard to predict, making it difficult to decide whether a certain treatment is indicated and what to say to the patient regarding prognosis. A new score recently has been proposed, which includes the parameters involved in the Child-Pugh stage, plus macroscopic tumor morphology, alpha-fetoprotein levels, and the presence or absence of portal thrombosis. The score has been validated in internal control series, but its general applicability has yet to be confirmed. The authors compared the discriminatory ability of the Cancer of the Liver Italian Program (CLIP) score with those of the Okuda and TNM staging systems and the Child-Pugh classification in a group of cirrhotic patients with HCC, diagnosed and followed up by their unit.

METHODS

One hundred fifty-four patients with histologically ascertained HCC in cirrhosis were recruited (median age, 62.5 years; male/female ratio, 122/32) and prospectively followed up. Staging was performed at the baseline using the Child-Pugh, Okuda, TNM, and CLIP systems.

RESULTS

The CLIP score was able to predict survival better than the Okuda or TNM staging system, as confirmed by the Kaplan-Meier comparison of survival curves and by the Cox regression analysis, with a median survival rate of 31, 27, 13, 8, 2, and 2 months in patients with CLIP Stages 0, I, II, III, IV, and V-VI, respectively. The Child-Pugh classification performed as well as the Okuda. The predictive capacity of CLIP score was confirmed in the subgroup of patients undergoing chemoembolization. Overall, the survival rate in the authors' series was higher than predicted on the basis of previous reports.

CONCLUSIONS

The CLIP score, which is based on simple features of the patient and of the tumor, can accurately identify patients with different prognoses, particularly in the early phases of HCC, thus representing a useful tool in the management of the disease and of the affected patient.

Follicular fluid enhances sperm motility and velocity in vitro

Forty-three follicular fluids (FFs) obtained during laparoscopy were tested in vitro for their effect(s) on sperm motility using gametes obtained by the swim-up procedure. Both the proportion of motile sperm and the velocity distribution patterns were evaluated as function of time by multiple-exposure photography technique. At the various incubation periods considered, all FFs maintained or then enhanced sperm motility as compared with the paired control suspension incubated with a sperm survival medium. The results of the sperm contact test for FFs from women who achieved pregnancy versus FFs from women who remained infertile were not significantly different for both parameters measured. Comparing these with our previously reported results, we may hypothesize that FF released at ovulation into the peritoneal cavity may counteract some sperm-immobilizing effect of peritoneal fluid, thereby increasing the fertility potential of the male gametes.

Central compensation of vestibular deficits. IV. Responses of lateral vestibular neurons to neck rotation after labyrinth deafferentation

The response characteristics of neurons located in the lateral vestibular nucleus (LVN) to neck rotation at 0.026 Hz, 10 degrees peak displacement, have been investigated in precollicular decerebrate cats submitted to ipsilateral acute (aVN) or chronic vestibular neurectomy (cVN). On the whole, 105 units were tested after aVN (i.e., during the first postoperative hours) and 132 units after cVN (i.e., after full compensation of the postural and locomotor deficits). The neurons were histologically located either in the rostroventral (rvLVN) or the dorsocaudal part (dcLVN) of Deiters' nucleus, which are known to project mainly to the cervical and the lumbosacral cord, respectively. Moreover, 55 units in the former group and 66 units in the latter group were identified as vestibulospinal neurons projecting to lumbosacral segments of the spinal cord. The responses of these 237 LVN neurons to the neck input were then compared with those of 120 LVN neurons recorded previously in decerebrate cats with intact labyrinths. Whereas 58.3% of the LVN units recorded in control experiments were responsive to neck rotation, 69.5% of the units were affected by this stimulation at the acute stage of the neurectomy and 74.2% at the chronic stage. This increase in responsive units after aVN and cVN with respect to the controls was found exclusively in the dcLVN. The mean discharge rate of the responsive LVN neurons decreased from 40.7 +/- 48.9 (SD) imp/s in control experiments to 22.1 +/- 15.8 (SD) imp/s after a VN. Similar value was also obtained after cVN [25.0 +/- 17.2 (SD) imp/s], suggesting that compensation of the postural deficits elicited by the vestibular neurectomy results from a redistribution of the excitatory drive within different populations of LVN neurons. Indeed, the relation found in control experiments, i.e., that the faster the conduction velocity of vestibulospinal axons the lower was the unit discharge at rest, was lost after aVN, due to a decrease in resting discharge of the slow units. The mean discharge rate of the slow units, however, recovered after cVN, so that the negative correlation between resting discharge rate and axonal conduction velocity was reestablished. The average gain and sensitivity of the first harmonic response of the LVN neurons to neck rotation recorded after aVN and cVN were comparable to those obtained in preparations with the vestibular nerves intact.(ABSTRACT TRUNCATED AT 400 WORDS)

Central compensation of vestibular deficits. II. Influences of roll tilt on different-size lateral vestibular neurons after ipsilateral labyrinth deafferentation

The activity of 168 Deiters' neurons projecting to lumbosacral segments of the spinal cord has been recorded in precollicular decerebrate cats after ipsilateral acute (aVN) or chronic vestibular neurectomy (cVN), and their response characteristics to sinusoidal stimulation of contralateral labyrinth receptors at the standard parameters (roll tilt at 0.026 Hz, 10 degrees peak displacement) have been related to cell size inferred from the conduction velocity of the corresponding axons. These findings were compared with those elicited in decerebrate cats with both vestibular nerves intact. In all experimental conditions, the higher the coefficient of variation (CV) of the vestibulospinal neurons, reflecting a more irregular unit discharge, the lower was the mean discharge rate at rest. However, the proportion of regularly discharging units (with the lowest CV) decreased after aVN but increased after cVN. The relation found in control experiments, i.e., the faster the conduction velocity of vestibulospinal axon the lower was the unit discharge at rest, was lost after aVN due to a decrease in resting discharge rate of the slow neurons. The mean discharge rate of these units, however, recovered after cVN, so that the negative correlation between resting discharge rate and axonal conduction velocity was reestablished. After aVN, the decrease in resting discharge rate of the slow vestibulospinal neurons was not associated with significant changes in gain (impulses per second per degree) of the unit responses to standard parameters of tilt, so that the sensitivity of these units (percentage change of the mean discharge rate per degree) increased; on the other hand, the resting discharge rate of the fast neurons, which remained almost unchanged after aVN, was associated with a significant increase in gain, thus leading to an average increase in response sensitivity of these units.(ABSTRACT TRUNCATED AT 400 WORDS)