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Biomedical subjects

G Levy

Publications and source records attributed to G Levy.

At least 37 records · Page 2Linked to original sources

Clinical correlates of action tremor in Parkinson disease.

BACKGROUND: Action tremor is often noted in patients with Parkinson disease (PD), yet the clinical correlates of this type of tremor have been the focus of few studies. It is not clear whether this action tremor is a manifestation of the underlying basal ganglia disease. OBJECTIVE: To determine whether the severity of action tremor in PD is associated with age, age at disease onset, disease duration, levodopa dose, severity of rest tremor, or other motor (ie, bradykinesia, rigidity) and nonmotor manifestations of PD. METHODS: Patients with PD (N = 197) were ascertained as part of a familial aggregation study. All patients underwent a neurological examination. Rest tremor was rated with the Unified Parkinson Disease Rating Scale; and action tremor, with the Washington Heights-Inwood Genetic Study of Essential Tremor Rating Scale. RESULTS: Action tremor was present in 184 (93.4%) of 197 patients. Four patients (2%) met criteria for definite essential tremor. The action tremor score was not associated with age, age at onset, or disease duration. The action tremor score was associated with the rest tremor score (r = 0.37; P<.001), and more strongly with the ipsilateral than contralateral rest tremor score. The association between the action tremor score and the rest tremor score was diminished but still significant (r = 0.21, P<.02) even when we excluded these 63 patients with re-emergent tremor. Neither the action nor the rest tremor score was associated with the bradykinesia or rigidity scores, Hoehn and Yahr scale score, or modified Mini-Mental State Examination score. CONCLUSIONS: Action tremor was associated with rest tremor in PD, suggesting that, at least in part, action tremor is a manifestation of the underlying basal ganglia disease. Neither tremor was associated with other motor and nonmotor manifestations of PD. This in turn suggests that tremor in PD may represent an underlying pathophysiological process different from these other manifestations.

Adult↗

A multicenter United States-Canadian trial to assess lamivudine monotherapy before and after liver transplantation for chronic hepatitis B.

Seventy-seven liver transplant candidates were enrolled in a multicenter study in which patients were treated with lamivudine (100 mg daily) without the adjunctive use of hepatitis B immune globulin. Treatment was begun while patients awaited liver transplantation and continued after transplantation. All were hepatitis B surface antigen (HBsAg) positive, and 61% had detectable hepatitis B e antigen (HBeAg) and HBV DNA when treatment was begun. Forty-seven underwent liver transplantation and 30 did not. Median study participation was 38 months (range, 2.7-48.5) in the transplanted patients and 26 months (range, 0.1-37) in the nontransplanted group. Twenty-five of 42 (60%) transplanted patients with 12 or more weeks of posttransplantation follow-up were HBsAg negative at the last study visit. At treatment week 156, 13 of 22 (59%) remained HBsAg negative, and all 9 reinfected patients were HBV-DNA positive before treatment. In the nontransplanted patients, HBeAg was initially detectable in 20 of 27 (74%) but this decreased to 3 of 17 (18%) after 104 weeks of treatment, and significant improvement in biochemical parameters was observed. HBV-DNA polymerase mutants were detected in 15 (21%) and 6 (20%) of the transplanted and nontransplanted patients, respectively. When compared with historical cohorts, lamivudine-treated patients appeared to have improved survival, and transplanted patients had a decrease in the rate of recurrent HBV infection. Lamivudine therapy was partially effective in preventing recurrent HBV infection when given before and after transplantation. Thus, future trials using a combination of HBIg and lamivudine are needed to assess the optimal prophylactic therapy.

Adult↗

A randomized double-blind comparative study of mycophenolate mofetil and azathioprine in combination with cyclosporine and corticosteroids in primary liver transplant recipients.

Acute hepatic allograft rejection occurs in approximately 50% to 60% of the patients undergoing liver transplantation. In this study, we compared the rate of acute rejection in liver transplant recipients randomized in a double-blind comparative study to treatment with mycophenolate mofetil (MMF) or azathioprine (AZA), both in combination with cyclosporine and corticosteroids. Five hundred sixty-five primary liver transplant recipients were randomly assigned to treatment with MMF, 1 g twice daily intravenously followed by 1.5 g twice daily orally (n = 278), or AZA, 1.0 to 2.0 mg/kg/d intravenously followed by oral administration (n = 287), in combination with cyclosporine and corticosteroids. Patients were followed up for at least 1 year, and efficacy analysis was based on intent-to-treat methods. Acute rejection was defined according to the Banff histological criteria. The two study groups were balanced for demographic and clinical baseline characteristics. The incidence of acute rejection or graft loss was 47.7% in the AZA patients and 38.5% in the MMF patients (P <.03). The incidence of biopsy-proven and treated rejection censoring for graft loss was 40.0% in the AZA group versus 31.0% in the MMF group (P <.06). Steroid-resistant rejection requiring treatment with either OKT3 or antithymocyte globulin occurred in 8.2% of AZA patients versus 3.8% in MMF patients (P <.02). Patient and graft survival rates at 1 year posttransplantation were 85.4% in the AZA group and 85.3% in the MMF group (P = not significant). MMF was superior to AZA in preventing acute rejection in the first 6 months posttransplantation. MMF and AZA were equivalent in preventing graft loss at 1 year, and the safety profiles between the two immunosuppressive agents were similar.

Acute Disease↗

Amino acid-induced translation of TOP mRNAs is fully dependent on phosphatidylinositol 3-kinase-mediated signaling, is partially inhibited by rapamycin, and is independent of S6K1 and rpS6 phosphorylation.

Vertebrate TOP mRNAs contain an oligopyrimidine tract at their 5' termini (5'TOP) and encode components of the translational machinery. Previously it has been shown that they are subject to selective translational repression upon growth arrest and that their translational behavior correlates with the activity of S6K1. We now show that the translation of TOP mRNAs is rapidly repressed by amino acid withdrawal and that this nutritional control depends strictly on the integrity of the 5'TOP motif. However, neither phosphorylation of ribosomal protein (rp) S6 nor activation of S6K1 per se is sufficient to relieve the translational repression of TOP mRNAs in amino acid-starved cells. Likewise, inhibition of S6K1 activity and rpS6 phosphorylation by overexpression of dominant-negative S6K1 mutants failed to suppress the translational activation of TOP mRNAs in amino acid-refed cells. Furthermore, TOP mRNAs were translationally regulated by amino acid sufficiency in embryonic stem cells lacking both alleles of the S6K1 gene. Inhibition of mTOR by rapamycin led to fast and complete repression of S6K1, as judged by rpS6 phosphorylation, but to only partial and delayed repression of translational activation of TOP mRNAs. In contrast, interference in the phosphatidylinositol 3-kinase (PI3-kinase)-mediated pathway by chemical or genetic manipulations blocked rapidly and completely the translational activation of TOP mRNAs. It appears, therefore, that translational regulation of TOP mRNAs, at least by amino acids, (i) is fully dependent on PI3-kinase, (ii) is partially sensitive to rapamycin, and (iii) requires neither S6K1 activity nor rpS6 phosphorylation.

Alleles↗

Excitatory and inhibitory corticospinal responses to transcranial magnetic stimulation in patients with minor to moderate head injury.

OBJECTIVES: The changes in excitatory and inhibitory responses to transcranial magnetic stimulation (TMS), as attested by motor evoked potential (MEP) and silent period (SP) parameters, were compared in patients who sustained minor to moderate head injury. METHODS: A total of 38 patients with brain concussion, and diffuse, focal, and combined brain injury and 20 healthy volunteers were examined. The MEPs and SPs were recorded from the abductor pollicis brevis muscle after single pulse TMS 2 weeks after head trauma. The parameters assessed were the MEP resting threshold, the MEP/M wave amplitude ratio, the central motor conduction time (CMCT), the SP threshold, the interthreshold difference (ITD), and the SP duration (SPD). RESULTS: The main finding was an increase in the ITD in patients with mild and moderate head injury due to the relatively greater augmentation of the MEP threshold. This was associated with a reduction of the MEP/M wave amplitude ratio. The degree of MEP and SP changes depended on severity of head injury and was not related to the type of brain lesions. The SPD did not differ significantly in brain concussion, or diffuse, focal and combined brain injury groups compared with the control group. The CMCT was prolonged in patients with diffuse and combined brain lesions. Among subjective complaints only fatigue was significantly related to ITD, MEP, and SP threshold abnormalities. CONCLUSIONS: The results suggest that mechanisms involved in MEP and SP generation are differently affected in head injury, the first being impaired more severely. The increase of the ITD accompanied by reduction of the MEP/M wave amplitude ratio may reflect a dissociated impairment of inhibitory and excitatory components of central motor control in head trauma.

Adolescent↗

Pharmacokinetics of metformin gastric-retentive tablets in healthy volunteers.

The single-dose pharmacokinetics of two gastric-retentive, extended-release tablet formulations of metformin hydrochloride in fed, healthy volunteers were compared with those of the currently marketed immediate-release metformin hydrochloride product. The plasma concentration-time profiles demonstrated extended-release characteristics from the gastric-retentive tablets. The mean bioavailability from each gastric-retentive tablet was approximately 115%, relative to the immediate-release (IR) product. Cmax values were lower and tmax values were greater for the gastric-retentive tablets compared with the IR product. In contrast to conventional extended-release metformin tablets reported in the literature, these gastric-retentive tablets showed extended-release plasma concentration profiles of metformin hydrochloride and increased bioavailability compared with the immediate-release tablet.

Adult↗

Influence of setting on unattended respiratory monitoring in the sleep apnoea/hypopnoea syndrome.

The high demand for full polysomnography and the better quality of sleep at home are the main reasons for performing home sleep studies. Home respiratory monitoring has been evaluated in several studies, but the influence of setting on the results of unattended respiratory monitoring has not been assessed to date. Unattended monitoring of respiratory variables at home and in the sleep laboratory was conducted in 35 consecutive patients with suspected sleep apnoea/hypopnoea syndrome. Respiratory variables during sleep, rate of successful studies and patient preference were compared. The data acquisition failure rate was 2.8% in the sleep laboratory and 5.7% at home. The mean difference between apnoea/hypopnoea indices (AHI) obtained from home and laboratory studies was -0.21 +/- 8 (95% confidence interval 3.27-2.84). Using the method comparison approach of Bland and Altman, the limits of agreement of the mean difference between AHI home and AHI laboratory were -16.7 and 17.1. No difference was observed between the studies in time spent in different body positions. When patients were asked where they would prefer to repeat the sleep study, 53% replied at home, 28% in hospital and 19% showed no preference. It was concluded that the setting of unattended respiratory monitoring (home or sleep laboratory) influences neither the number of valid studies nor the results of the respiratory parameters measured; most patients, however, preferred home studies.

Adult↗

Getting at the variable expressivity of von Willebrand disease.

Von Willebrand disease (VWD) is a heterogeneous bleeding disorder caused by abnormalities of von Willebrand factor (VWF). VWF levels vary widely in the general population, and this variation is likely to be a major factor accounting for the incomplete penetrance and variable expressivity of VWD. In addition, variation in VWF level may play an important role in determining the risk of venous thrombosis. A large component of the variation in VWF level in the general population has been shown to be attributable to genetic factors. This review will focus on the current understanding of the genetic causes for variation in VWF level, and will highlight future directions for getting at the variable expressivity of von Willebrand disease.

ABO Blood-Group System↗

Motor impairment in PD: relationship to incident dementia and age.

OBJECTIVE: To analyze the relationship of specific motor impairment in idiopathic PD to incident dementia. BACKGROUND: The total Unified PD Rating Scale (UPDRS) motor score at baseline has been associated with an increased risk of developing dementia in PD. METHODS: A cohort of 214 nondemented community-dwelling patients with PD was followed annually with neurologic and neuropsychological evaluations. The association of baseline motor impairment with incident dementia was analyzed using Cox proportional hazards models. Facial expression, tremor, rigidity, and bradykinesia were analyzed as part of subscore A (indicative of dopaminergic deficiency); speech and axial impairment were analyzed as part of subscore B (indicative of predominantly nondopaminergic deficiency). The correlation between the six motor domains and age was also analyzed. RESULTS: Of 173 patients followed for at least 1 year, 50 became demented according to the Diagnostic and Statistical Manual of Mental Disorders, revised 3rd edition (DSM III-R) criteria (mean follow-up, 3.6 +/- 2. 2 years). When both subscores A and B were entered into the Cox model, subscore B was associated with incident dementia (relative risk = 1.19; 95% CI, 1.09 to 1.30; p = 0.0001), in addition to gender, age, and education, whereas subscore A was not (relative risk = 1.03; 95% CI, 0.99 to 1.07; p = 0.19). Of the six motor domains, speech and bradykinesia were associated with incident dementia (p < 0.05), and axial impairment approached significance (p = 0.06). Only axial impairment was correlated with age (correlation coefficient = 0.32; p < 0.001). CONCLUSION: The findings suggest that motor impairment mediated predominantly by nondopaminergic systems is associated with incident dementia in PD. Axial impairment may be the result of a combined effect of the disease and the aging process.

Age Factors↗

Human herpesvirus-6 is associated with cytomegalovirus reactivation in liver transplant recipients.

Human herpesvirus-6 (HHV-6) may be a risk factor for cytomegalovirus (CMV) disease in posttransplant patients, possibly through a direct interaction or through a general immunomodulatory effect. To examine this possibility, 88 liver transplant recipients were monitored with serial HHV-6 polymerase chain reaction (PCR), CMV antigenemia, and CMV plasma viral load. HHV-6 infection was defined by a positive PCR of peripheral blood lymphocytes. Forty-eight (54.4%) of 88 patients had at least 1 positive HHV-6 PCR. CMV recurrence was significantly more common in patients with HHV-6 infection (38/48 patients [79. 2%]), compared with recurrence in those without HHV-6 infection (18/40 patients [45%]; P=.001). Peak CMV viral load was 24, 147+/-6799 copies/mL in patients with HHV-6 infection versus 8391+/-4598 copies/mL in patients without HHV-6 infection (P=.001). Symptomatic CMV disease was more common in patients with HHV-6 infection than it was in those without infection (15/48 patients [31. 3%] vs. 4/10 patients [10.0%]; P=.013). In a multivariate analysis including other risk factors for CMV, HHV-6 infection remained an independent risk factor for CMV disease (P=.013; odds ratio, 7.26; 95% confidence interval, 1.52-34.72). HHV-6 is associated with CMV infection and disease, thus supporting an interaction between these viruses.

Adolescent↗

Isoniazid prophylaxis in lung transplantation.

The incidence of tuberculous disease (TD) is higher in lung-transplant patients than in the general population. During a 7-year period, we included 61 patients who underwent lung transplantation in a prospective isoniazid prophylaxis protocol. Isoniazid was prescribed to infected and anergic patients not previously treated when added to the waiting list. Six of 61 patients (10%) developed tuberculosis. We observed no differences in tuberculous disease incidence between infected-anergic and non-infected patients. In our tuberculous-endemic area, isoniazid prophylaxis is safe and offers protection from TD to infected and anergic patients who must be enrolled in a lung transplantation program.

Adolescent↗

Self-reported sleepiness while driving as a risk factor for traffic accidents in patients with obstructive sleep apnoea syndrome and in non-apnoeic snorers.

The obstructive sleep apnoea syndrome (OSAS) is a condition causing daytime sleepiness and has been related to an increased risk for traffic accidents. However, the evidence linking severity of OSAS to a higher rate of automobile crashes is based on limited data. The aims of this study were to study the traffic accident rate in the last 5 years in patients referred to our sleep clinic because of clinical suspicion of OSAS and to analyse variables related to an increased risk for traffic accidents. A series of 189 consecutive patients with a driving license referred for a sleep study because of OSAS clinical suspicion and a control group (CG) of 40 hospital staff workers who denied snoring, matched for age and sex with the study population, were studied. Patients underwent a full-night polysomnography and both patients and the CG completed a self-answered questionnaire. One hundred and twenty-two patients were diagnosed as OSAS and 67 patients as non-apnoeic snorers (NAS). The self-reported number of accidents was significantly higher in OSAS patients compared with CG. The self-reported number of times off the road was significantly higher in OSAS patients compared with NAS and with CG. Variables associated with an increased risk for traffic accidents were self-reported sleepiness while driving (OR 5, 95%CI 2.3-10.9), having quit driving because of sleepiness (OR 3, 95%CI 1.1-8.6) and being currently working (OR 2.8, 95%CI 1.1-7.7). We conclude that self-reported sleepiness while driving is associated with an increased risk for traffic accidents in OSAS patients and in NAS. We suggest that this symptom can be used to alert patients and to give priority in the sleep clinic for study and treatment.

Accidents, Traffic↗

Fetal distress increases interleukin-6 and interleukin-8 and decreases tumour necrosis factor-alpha cord blood levels in noninfected full-term neonates.

OBJECTIVE: To assess the influence of fetal distress on interleukin-1beta, interleukin-6, interleukin-8 and on tumour necrosis factor-alpha blood levels in noninfected full-term neonates. STUDY DESIGN: In a multicentre prospective study, cord blood samples were obtained at time of delivery from 234 noninfected full-term neonates for the purposes of measuring serum levels of interleukin-1beta, interleukin-6, interleukin-8 and tumour necrosis factor-alpha using immunoassays. Women were classified into four groups according to the mode of delivery (vaginal delivery or caesarean section) and the presence or absence of fetal distress. The role of labour was also investigated. RESULTS: No significant relationship was found between cytokine cord blood levels and the mode of delivery. Fetal distress was associated with an increase in interleukin-6 (P = 0.01) and interleukin-8 (P < 0.001) levels, and a decrease in tumour necrosis factor-alpha (P < 0.001). Labour was also associated with a significant increase in interleukin-6 and interleukin-8 cord blood levels (P = 0.01 and P < 0.001, respectively). CONCLUSION: Fetal distress and labour were each associated with elevated interleukin-6 and interleukin-8 cord blood levels in noninfected full term neonates while only fetal distress was associated with decreased tumour necrosis factor-alpha levels.

Delivery, Obstetric↗

Impact of absorption profiling on efficacy and safety of cyclosporin therapy in transplant recipients.

The optimisation of cyclosporin therapy remains a challenge because of the very narrow therapeutic window and the highly variable pharmacokinetics of the drug. Therefore, there has been a concerted effort in the clinical transplant community to explore and test cyclosporin monitoring tools and techniques that will allow blood concentrations of cyclosporin to be maintained within the narrow therapeutic window in order to maximise efficacy and minimise toxicity. Absorption profiling is a simple and accurate technique for adjusting dosages of cyclosporin microemulsion that utilises an estimation of the rate and extent of cyclosporin absorption in order to optimise immunosuppression in the individual patient. Two estimation tools in particular are an abbreviated area under the concentration-time curve (AUC) for the first 4 hours postdose and a single sampling point at 2 hours postdose. These 2 monitoring strategies have not only been validated as an accurate estimation of cyclosporin bioavailability but have been demonstrated to significantly improve clinical outcomes in patients compared with traditional trough concentration monitoring. The evidence presented in this review demonstrates that absorption profiling results in the following clinical benefits compared with trough concentration monitoring: (i) reduced incidence of acute rejection; (ii) reduced severity of rejection episodes; (iii) reduced nephrotoxicity; and (iv) a rational basis for dosage adjustments. The optimisation of immunosuppressive therapy continues to be a major priority in the management of the organ transplant recipient. Absorption profiling is a sensitive and practical approach for optimising the dosage of cyclosporin microemulsion, and can further extend the benefits of cyclosporin immunosuppression in the individual patient.

Age Factors↗