Is Inferior Alveolar Nerve Block Needed to Perform Implant Surgery in the Posterior Mandible? A Randomized Controlled Trial

PURPOSE

There is no agreement in the literature on whether inferior alveolar nerve block (IANB) or infiltration (INF) is the anesthetic technique of choice for placing implants in the posterior mandible. This study aimed to compare the efficacy of the 2 techniques using articaine 4% with epinephrine 1:100,000.

MATERIAL AND METHODS

The trial was a comparison between 2 parallel groups of patients, who received implants distal to the mental foramen, either with IANB or INF. The anesthetic technique was the predictor variable. The primary outcome was patients' perceived pain by a numerical rating scale (NRS) in incision, osteotomy and suture. The secondary outcome, patients' satisfaction, was equally recorded 12 hours after surgery. The dataset were first analyzed by descriptive statistics. Then, Mann-Whitney test, Spearman's coefficient and regression models were used. This trial followed the recommendations of the Consort Statement for reporting RCTs.

RESULTS

Ninety-six patients (41 men, 55 women, mean age 55.76 years) were randomly assigned to either group, IANB or INF, of 48 patients each. Only 20% of patients reported pain values >0 (range 0-4 of 10). Medians were: 0 (0-0) for both groups (P = .956, .175 and .908, incision, osteotomy and suture, respectively). Mean satisfaction was high in both groups, 9.0 ± 1.0, median 10; and 8.8 ± 1.7, median 9, for IANB and INF (P = .695). Hence, the anesthetic technique did not generate statistically significant differences. Five potential influencing variables that were measured did not significantly affect pain levels or patient satisfaction in either group.

CONCLUSIONS

According to the results, an IANB might not be necessary for standard implant surgery in the posterior mandible, and infiltration of articaine 4% with epinephrine 1:100,000 appears to be sufficient. Further research is needed to check if these results are extensible to other anesthetic drugs.

The Benefits Experience by Families Participating in the Watersports Inclusion Games

Aims The Watersports Inclusion Games (Inclusion Games) is a free event for children and families with disability to participate in water-based activities. Family participation in physical activity can improve mental health and confidence in children with disability. This study aims to gain an insight into the benefits and barriers of participation, perceived by parents and carers. Methods After an initial literature review, an online pre-event and post-event survey was constructed via SurveyMonkey. Both surveys were circulated three times to attendees. Statistical and thematic analysis was carried out to compare changes in responses both before and after the event. Results 49% of participants were primarily hoping to experience a new sport in a controlled environment and meet others with similar challenges. The surveys also highlighted an increase in reported family bonding [P=0.14] due to the event. A thematic analysis revealed event organisation and planning is vital for effective participation of children with disability. Conclusion Creating an equal opportunity for young people with disabilities and their families to partake in watersports led to increased confidence and a higher likelihood of future participation. Effective organisation and extra help were key enabling factors facilitating these benefits.

Burnout among Portuguese radiographers during the COVID-19 pandemic

INTRODUCTION

The COVID-19 pandemic has had a global impact, including in health services, placing health professionals under enormous tension, pressure, and stress. Professionals involved in the care, diagnosis, and treatment of COVID-19-infected patients have been subject to emotional and physical distress that can potentially enhance the development of occupational diseases. The aim of this study was to assess the impact of the COVID-19 pandemic on the incidence of burnout among Portuguese radiographers.

METHODS

This was a cross-sectional, quantitative study. Burnout levels were estimated using the Maslach Burnout Inventory-Human Services Survey, composed of 22 questions. Specific questions were developed to characterize the socio-demographic situation and the impact of the pandemic on the radiographers. Data were descriptively analyzed and Mann-Whitney and Kruskal-Wallis tests were used for correlation analysis.

RESULTS

The study sample comprised 386 radiographers, 68.7% of whom where female and 31.3% male. The mean sample age was 36.3 (±9.1) years. A total of 43.5% and 45.5% of subjects had a high level of emotional exhaustion and depersonalization, respectively, and 59.8% experienced low personal accomplishment. Altogether, 23.3% of study participants were at high risk of burnout in the three dimensions assessed and 77.2% in at least one.

CONCLUSION

Study results showed that radiographers were at high risk of developing burnout in the COVID-19 pandemic setting. Health institutions should actively monitor these professional's mental health and develop restorative strategies that enable their emotional wellbeing, preventing absenteeism and increasing patients' quality of care.

IMPLICATIONS FOR PRACTICE

Burnout of health professionals has a strong impact on health services organization, resulting in increased absenteeism and error probability, frequent work delays, low productivity and job satisfaction, inter- and intra-professional conflicts, high job turnover, high job quit, and decreased quality of care perceived by users.

[Inherited bleeding disorders in adolescents with excessive menstrual bleeding. Should we evaluate the fibrinolytic pathway?]

INTRODUCTION

Heavy Menstrual Bleeding (EMB) is a frequent problem in adolescence. The prevalence of inherited bleeding disorders (IBD) as a cause of EMB is not well established and the involvement of fibri nolytic pathway defects has been poorly explored.

OBJECTIVE

To determine the prevalence of IBD and fibrinolysis defects in adolescents with EMBs.

PATIENTS AND METHOD

93 adolescents (11 to 18 years old) were included. Personal and family history of bleeding were obtained through a standard ized questionnaire. The following lab tests were performed: prothrombin time (PT), activated partial thromboplastin time (aPTT), von Willebrand factor quantification, and platelet count and function. Those patients who were not diagnosed with IBD were further evaluated with clot lysis time assay.

RESULTS

41 patients (44%) were diagnosed as IBD (Von Willebrand disease n = 28, platelet func tion defects n=8, mild hemophilia n = 5. Decreased clot lysis time was found in 31 patients. 54% of patients diagnosed with IBD had EMB as the first hemorrhagic manifestation.

CONCLUSION

These results support the need to evaluate the coagulation process, including the fibrinolytic pathway in the study of adolescents with EMB.

P1261 A heart with red flags

A 67 years old woman with a previous history of hypertension, atrial fibrillation (AF) and known severe concentric hypertrophy (more pronounced at the interventricular septum) with moderate pulmonary hypertension and diastolic dysfunction of the left ventricle (LV) resorted to the urgency service for weight loss, asthenia and dyspnea for minor efforts. Her physical examination was innocent. Her ECG showed AF and low voltage in limb and precordial leads. Patient was admitted at the Cardiology Department for investigation. A new TTE revealed fast progression of the hypertrophic pattern (IVS 26 mm, and posterior wall 18 mm) with a rest outflow tract gradient of 18 mmHg; free right ventricular wall was also hypertrophied with 12 mm and a type II diastolic dysfunction was present. A complete investigation for ventricular hypertrophy and constitutional syndrome was done. CMR demonstrated preserved biventricular systolic function, LV hypertrophy with septal predominance (24 mm) with elevated myocardial mass indexed to body mass (114 g/m2) and late difuse subendocardial gadolinium enhancement. (99m)Tc -DPD scintigraphy was negative for ATTR; Anderson-Fabry disease was excluded by genetic testing. Blood analysis revealed a normocytic/ normochromic anemia and a disproportional ratio of free light immunoglobulin chains K/λ, with a predominance of lambda chains. β2-microglobulin was also elevated. 24 hours urine analyses were normal. The hypothesis of non-secretor multiple myeloma (MM) with light chain immunoglobulin amyloidosis (AL) was then admitted. The patient underwent bone marrow and salivary gland biopsies which confirmed MM and deposition of amyloid, respectively. The FISH analyses demonstrated a delection of RB1 gene on 13q14.3 sequence and of TP53 on 17p13.1, both associated with a poorly prognosis in MM. The patient was referred for oncology where she is currently undergoing chemotherapy for MM and AL amyloidosis.

Amyloidosis represents a large spectrum of systemic diseases. Heart failure may be its first sign. This case reflects the diagnostic work-up in the presence of a hypertrophic LV pattern as well as the importance of high clinical suspicious and early diagnosis. While AL amyloidosis occurs in isolation, 10% of patients with multiple myeloma develop systemic AL amyloid with cardiac involvement. The distinction between these entities is not only semantic, but has extremely important prognosis and therapeutic considerations.

Feasibility and Safety of Endoscopic Ultrasound-Guided Biliary Drainage (EUS-BD) for Malignant Biliary Obstruction Associated with Ascites: Results of a Pilot Study

BACKGROUND

It has been suggested that EUS-BD may be a feasible and safer alternative to percutaneous transhepatic biliary drainage (PTBD) after failed ERCP in patients with ascites. To date, no study has specifically evaluated the performance of EUS-BD in this context.

METHODS

Retrospective analysis was done for patients with and without ascites who underwent EUS-BD for malignant biliary obstruction after failed ERCP between July 2010 and September 2014. Complications and technical and clinical successes between the two groups were compared.

RESULTS

A total of 31 patients were included: 20 patients without ascites (group 1) and 11 with ascites (group 2). Nineteen patients underwent EUS-hepaticogastrostomy (six in group 2), and 12 underwent EUS-choledochoduodenostomy (five in group 2). Technical success was achieved in all patients. Clinical success was observed in 95% (n = 19) in group 1 and 64% (n = 7) in group 2 (p = 0.042). In three out of four patients without clinical success in group 2, the follow-up period was not long enough to observe the clinical response because of early death within the 2 weeks after EUS-BD secondary to disease progression or preprocedural unresponsive sepsis. No significant differences were observed between groups 1 and 2 either in the overall rates of procedural-related complications (20 and 9%, respectively, p = 0.63) or in the rates of major complications (15 vs 9%, respectively, p = 0.639). Stent migration occurred in one patient in each group, intra- or post-procedural bleeding occurred in two patients in group 1, which was conservatively managed, and one patient in group 1 presented biliary leakage. Stent patency and the number of re-interventions were not significantly different.

CONCLUSIONS

EUS-BD is technically feasible in patients with ascites. Our results suggest that EUS-BD may be a clinically effective and safe alternative after failed ERCP in patients with ascites.

Phosphoramidates as Potent Prodrugs of anti-HIV Nucleotides: Studies in the Amino Region

Novel phosphoramidate derivatives of the anti-HIV nucleoside analogues AZT and d4T have been prepared by phosphorochloridate chemistry. These materials are designed to act as labile membrane-soluble prodrugs of the bio-active free nucleotides. All compounds were fully characterised by a range of methods and were subjected to evaluation in vitro of their anti-HIV efficacy. A notable feature of the current study was that any attempt to replace the amino acid moiety of the phosphoramidate with a simple amine lead to a marked, virtually total loss of activity. Such simple phenyl alkylamino phosphate derivatives of either d4T or AZT inhibit HIV replication at cytotoxic concentrations and have no detectable antiviral selectivity. This clearly highlights the vital role played by the amino acid in the antiviral efficacy of the blocked phosphoramidates.

Novel Nucleoside Phosphoramidates as Inhibitors of HIV: Studies on the Stereochemical Requirements of the Phosphoramidate Amino Acid

Novel phosphoramidate derivatives of the anti-HIV nucleoside analogue d4T were designed to act as labile membrane-soluble prodrugs of the bio-active free nucleotide d4TMP. We herein reveal the very marked dependence of the antiviral activity of these phosphoramidates upon the stereochemistry of the amino acid attached to the phosphate centre; with a strong preference for the L-stereochemistry. These phosphate triesters were shown to liberate amino acid derivatives of the nucleotide intracellularly. These novel analogues, typified by alaninyl d4T monophosphate, may act as intracellular sources of the free nucleotides. The alaninyl d4T adducts themselves exert an antiviral effect when administered extracellularly, but again with clear distinctions between the L- and D-series. This evidence indicates that extracellularly administered blocked triesters derived from L-amino acids can generate d4TMP intracellularly, by a new pathway which is highly dependent on the amino acid stereochemistry.

Receptor-interacting protein 2 is a marker for resolution of peritoneal dialysis-associated peritonitis

There are no predictive factors for peritoneal dialysis-associated peritonitis; however, its resolution correlates with a cell-mediated Th1 immune response. We tested the hypothesis that induction of receptor-interacting protein 2 (RIP2), an assumed kinase linked with Th1 responses, is a useful marker in this clinical setting. Basal RIP2 expression was measured in human immune cells and during dialysis-associated peritonitis. RIP2 increased with bacterial toxin cell activation and the temporal profile for this differed depending on immune cell involvement in the innate or adaptive phases of the response. Importantly, RIP2 expression increased in peritoneal immune cells during dialysis-associated peritonitis and this upregulation correlated with clinical outcome. An early induction in peritoneal CD14(+) cells correlated with rapid resolution, whereas minimal induction correlated with protracted infection and with catheter loss in 36% of patients. These latter patients had higher levels of MCP-1 consistent with a delayed transition from innate to adaptive immunity. Our study shows that upregulation of RIP2 is a useful marker to monitor dialysis-associated peritonitis and in predicting the clinical outcome of these infections.

Lack of effect of the ghrelin gene-derived peptide obestatin on cardiomyocyte viability and metabolism

Obestatin is a recently discovered peptide encoded by the ghrelin gene that opposes ghrelin effects on food intake and gastrointestinal function. The biological activity of obestatin depends on amidation at its carboxyl terminus and on its postulated binding to the orphan G protein-coupled receptor 39 (GPR39). We have previously demonstrated that ghrelin is synthesized by cardiomyocytes and has direct effects on its viability. Our aim was to know if obestatin, derived from the same gene as ghrelin, also affects cardiomyocyte physiology. By RT-PCR and immunocytochemistry we have demonstrated that murine cardiomyocytes cultured in vitro and human atrial tissue express GPR39 receptor. Competitive binding studies with radioiodine 125I-labeled obestatin recognized specific binding sites for this peptide in the murine cardiomyocyte cell line HL-1. However, obestatin did not modify the cell cycle or viability of these cells, and it was not able to prevent the cytosine arabinoside-induced apoptosis of HL-1 cardiomyocytes, as assessed by Hoechst dye vital staining, flow cytometry analysis and determination of lactate dehydrogenase in the culture media. Finally, treatment with obestatin did not affect fatty acid or glucose uptake by HL-1 cardiomyocytes. In conclusion, obestatin is not a relevant metabolic or viability modifier for cardiomyocytes.

Thapsigargin-sensitive cationic current leads to membrane depolarization, calcium entry, and insulin secretion in rat pancreatic beta-cells

Glucose-induced insulin secretion by pancreatic beta-cells depends on membrane depolarization and [Ca2+]i increase. We correlated voltage- and current-clamp recordings, [Ca2+]i measurements, and insulin reverse hemolytic plaque assay to analyze the activity of a thapsigargin-sensitive cationic channel that can be important for membrane depolarization in single rat pancreatic beta-cells. We demonstrate the presence of a thapsigargin-sensitive cationic current, which is mainly carried by Na+. Moreover, in basal glucose concentration (5.6 mM), thapsigargin depolarizes the plasma membrane, producing electrical activity and increasing [Ca2+]i. The latter is prevented by nifedipine, indicating that Ca2+ enters the cell through L-type Ca2+ channels, which are activated by membrane depolarization. Thapsigargin also increased insulin secretion by increasing the percentage of cells secreting insulin and amplifying hormone secretion by individual beta-cells. Nifedipine blocked the increase completely in 5.6 mM glucose and partially in 15.6 mM glucose. We conclude that thapsigargin potentiates a cationic current that depolarizes the cell membrane. This, in turn, increases Ca2+ entry through L-type Ca2+ channels promoting insulin secretion.

Epithelioid hemangioendothelioma and multiple thoraco-lumbar lateral meningoceles: two rare pathological entities in a patient with NF-1

Epithelioid hemangioendothelioma (EHE) is a rare vascular soft-tissue tumour of intermediate malignancy. Neurofibromatosis type I (NF-1) is a genetic syndrome associated with soft tissue sarcoma and higher risk of developing neoplasia. Lateral meningoceles are uncommon entities, being mostly associated with NF-1. We report a case of a 31-year-old woman, with NF-1 and past history of right thalamic/peduncular astrocytoma WHO grade II, admitted to the Neurosurgery Department in December 2003 due to severe low back pain, irradiating to the left leg without a radicular pattern. Thoraco-lumbar magnetic resonance imaging (MRI) showed a large left posterior paravertebral expansive lesion, bilateral and multiple thoraco-lumbar lateral meningoceles and dural ectasias with scalloping of the vertebral bodies. Biopsy of the paravertebral mass lesion disclosed EHE. We present this case because of the novel association between NF-1 and EHE, and the unusual aggressiveness of the neoplasia. Additionally, we highlight the co-existence of bilateral and multiple lateral meningoceles.

[Complete congenital atrioventricular block]

Congenital atrioventricular block is defined (Yater) as a documented conduction defect in a young subject with unquestionable bradycardia in the absence of a history of infection which might have caused the condition. This condition may be isolated or associated with structural cardiac disease. Isolated block is often observed in patients with mothers suffering from autoimmune disease, often clinically latent. Anti-Ro/SS-A and La/SS-B antibodies cross into the fetal circulation and cause inflammation of the fetal conduction system. The diagnosis of the conduction defect is sometimes made during fetal life by echocardiography. Echocardiography assesses fetal hemodynamic status and may detect signs of fetal deterioration. Long-term follow-up studies have revised the previously considered good prognosis of isolated congenital atrioventricular block but advances in cardiac pacing provide satisfactory treatment. Follow-up by Holter monitoring, exercise testing and echocardiography is justified in children and adolescents; the patients may become symptomatic at any age. Indications for permanent pacing in pediatric patients have been difficult to determine due to the lack of data from controlled studies and multicenter trials. Pacing is not always easy in children. Epicardial pacing is advocated in small patients (< 5 years of age or 30 kg in weight). A pacing mode which restores the normal atrioventricular sequence is theoretically superior to single ventricular pacing even with rate responsive frequency.

[Angioplasty in aortic coarctation and recoarctation in children and adolescents]

STUDY OBJECTIVE

To determine the efficacy of percutaneous balloon angioplasty in children and adolescents with Coarctation and Recoarctation of the Aorta.

DESIGN AND SETTING

We dilated native coarctation and recoarctation after a complete hemodynamic and angiographic assessment of the situation in a young population referred to a university hospital.

PATIENTS AND INTERVENTION

In 22 patients with coarctation or recoarctation of the aorta, the systolic pressure gradient and the internal diameter of the stenotic area were measured before and after dilation, with a balloon catheter with an insufflation diameter no greater than the aortic diameter measured at the level of the diagram muscle. No infants were included nor patients with a rare aortic anatomy.

RESULTS

A significant gradient reduction from 36.59 +/- 12.03 mm Hg to 10.45 +/- 7.52 mm Hg, as well an increase from 4.54 +/- 2.04 mm to 8.05 +/- 2.82 mm in aortic internal diameter, were achieved with no complications.

CONCLUSIONS

Similar results were obtained both in native coarctation and recoarctation without significant complications. Age selection, aortic anatomy and balloon size were the major determinants of success.

Characterization of the activation pathway of phosphoramidate triester prodrugs of stavudine and zidovudine

The phosphoramidate triester prodrugs of anti-human HIV 2', 3'-dideoxynucleoside analogs (ddN) represent a convenient approach to bypass the first phosphorylation to ddN 5'-monophosphate (ddNMP), resulting in an improved formation of ddN 5'-triphosphate and, hence, higher antiviral efficacy. Although phosphoramidate derivatization markedly increases the anti-HIV activity of 2',3'-didehydro-2', 3'-dideoxythymidine (d4T) in both wild-type and thymidine kinase-deficient CEM cells, the concept is far less successful for the 3'-azido-2',3'-dideoxythymidine (AZT) triesters. We now investigated the metabolism of triester prodrugs of d4T and AZT using pure enzymes or different biological media. The efficiency of the first activation step, mediated by carboxylesterases, consists of the formation of the amino acyl ddNMP metabolite. The efficiency of this step was shown to be dependent on the amino acid, alkyl ester, and ddN moiety. Triesters that showed no conversion to the amino acyl ddNMP accumulated as the phenyl-containing intermediate and had poor, if any, anti-HIV activity. In contrast to the relative stability of the triesters in human serum, carboxylesterase-mediated cleavage of the prodrugs was found to be remarkably high in mouse serum. The subsequent conversion of the amino acyl ddNMP metabolite to ddNMP or ddN was highest in rat liver cytosolic enzyme preparations. Although L-alaninyl-d4TMP was efficiently converted to d4TMP, the main metabolite formed from L-alaninyl-AZTMP was the free nucleoside (AZT), thus explaining why d4T prodrugs, but not AZT prodrugs, retain anti-HIV activity in HIV-infected thymidine kinase-deficient cell cultures. The rat liver phosphoramidase responsible for the formation of ddNMP was shown to be distinct from creatine kinase, alkaline phosphatase, and phosphodiesterase.

Factors predictive of outcome on admission to an acute geriatric ward

AIM

To investigate which factors predict outcome of elderly patients on discharge and at 6 months.

METHODS

A prospective study in an acute geriatric ward. Within 48 h of admission, patients were assessed for social factors, geriatric problems, admission diagnoses, medication, function and mental ability. Outcome measures were mortality, length of stay, institutionalization, readmissions and attendance at accident and emergency within 6 months.

RESULTS

353 patients were studied, with a mean age of 81.8 years. Logistic regression analyses showed that variables predicting hospital mortality were Barthel index on admission, pre-morbid disability and polypharmacy. The only variable independently predictive of prolonged stay in hospital was a Barthel score of <45 on admission. Functional disability on admission was predictive of institutionalization on discharge. Variables predicting mortality within 6 months of discharge were Barthel index on admission <65, presence of pressure sores, malnutrition and polypharmacy. Variables independently predictive of institutionalization were mental state and a low pension. Those who took more than five drugs on admission were more likely to attend accident and emergency and be readmitted.

CONCLUSION

Limited activities of daily living and geriatric problems on admission are the strongest predictive factors of outcome, independent of diagnoses.

[Ductus closure in adults with the Rashkind device: comparative results]

INTRODUCTION

Catheter occlusion of the persistent ductus arteriosus with Rashkind device is an alternative to the surgical closure demonstrated in children, however a few results have been reported of occlusion in adults.

METHOD

From 1990 to 1996 in 127 patients with persistent ductus arteriosus undergoing occlusion by Raskind device. Two groups according age: 105 children (< 14 years) and 22 adults (> 14 years), were studied retrospectively. The results were analysed by immediate aortogram and follow-up at 24 hours, 6 and 12 months by color-Doppler echocardiograms.

RESULTS

The adults were frequently asymptomatic (86%) and with high incidence (59%) of silent ductus. Similar QP/QS (1.61 +/- 0.47 in adults vs 1.49 +/- 0.51) was calculated although pulmonary pressure was superior in children (12.50 +/- 2.97 vs 16.84 +/- 5.88 mmHg; p = 0.003). In group > 14 years the ductal anatomy favorable (Krichenko type A or B) was more frequent (91% vs 73%; p = 0.06) and ductal diameter significantly higher (3.03 +/- 1.50 vs 2.41 +/- 0.96 mm; p = 0.009). In adults 17 mm umbrella were used more frequently (91 vs 61%; p = 0.02). Absence complications (embolization, bacteremia, haemolysis, proximal stenosis of the left pulmonary artery) were found in adults against 4.72% in children. The occlusion were more effective in adults specially in early controls: 55% vs 34% (p = 0.09), 82% vs 69%, 91% vs 77% and 95% vs 83% (p > 0.10). Multivariate analysis identified age as an independent predictor of complete occlusion.

CONCLUSION

Our experience in transcatheter occlusion of persistent ductus arteriosus with Rashkind device in adults support the efficacy, safety and excellent early results despite higher incidence of silent asymptomatic ductus.

Antigens and antibodies in sera from human cases of epilepsy or taeniasis from an area of Mexico where Taenia solium cysticercosis is endemic

Human neurocysticercosis is an important parasitic disease in developing countries. Most epidemiological studies on the disease have used antibody-based assays that allow the detection of transmission 'hot spots' and the identification of the main risk factors for transmission. However, such assays have low predictive value in the detection of active cases of neurocysticercosis. The screening potential of the most commonly used antibody-detection technique, the electroimmunotransfer blot assay (EITB), has now been compared with an antigen-capture assay, in an endemic region of Mexico. The subjects were 68 patients with late-onset epilepsy, 35 cases of taeniasis and a randomly selected, control group of 133 individuals from the same region. Parasite-specific antibodies and antigens were more common among the epileptics and taeniasis cases than among the controls. The antigens appeared to be associated with late-onset epilepsy and the antibodies with the presence of subcutaneous nodules. The sensitivities of both tests, to detect epilepsy or taeniasis, were low, but the specificity and the positive predictive value of the antigen-capture assay was high when used with the epileptics. As late-onset epilepsy and neurocysticercosis seem to be associated in endemic regions, antigen-capture assays are probably the most reliable method of detecting active cases of neurocysticercosis in epidemiological studies.

Metabolism and anti-HIV activity of phosphoramidate derivatives of D4T-MP with variations in the amino acid moiety

The metabolism of different phosphoramidate prodrugs of d4T-MP, in which the phosphate group is linked to a phenyl group and the alkyl ester of an amino acid was studied in crude CEM cell extracts. Significant (80-100%) conversion to the amino acyl d4T-MP metabolite was obtained with derivatives containing L-alanine or methyl-L-aspartic acid. A lower degree of conversion was seen with derivatives containing L-phenylalanine, L-methionine, methyl-L-glutamic acid or L-leucine. Derivatives containing D-alanine, beta-alanine, glycine, L-valine or L-lactate showed no conversion to the amino acyl d4T-MP metabolite. Overall, there was a close correlation between the anti-HIV activity of these prodrugs and their conversion rate to the amino acyl d4T-MP metabolite. Our data suggest that the enzymes involved in the formation of the amino acyl d4T-MP metabolite have a rather stringent specificity for L-alanine as the amino acid moiety. In addition, these enzymes were found to be markedly species-dependent, their activities being highest in mouse serum, followed by guinea pig serum, but only minimal in human serum. Mouse serum therefore appears to be the medium of choice to isolate and identify the enzymes that are involved in the metabolism of these phosphoramidate prodrugs.

Marked inhibitory activity of masked aryloxy aminoacyl phosphoramidate derivatives of dideoxynucleoside analogues against visna virus infection

Lipophilic masked aryloxyaminoacylphosphoramidate derivatives of 2',3'-dideoxynucleoside (ddN) analogues with potent anti-HIV activity (i.e., stavudine [d4T], azidothymidine [AZT], dideoxycytidine [ddC], 3'thio-2',3'-dideoxy cytidine [3TC], dideoxyadenosine [ddA], and 2',3'-didehydro-2',3'-dideoxyadenosine [d4A]) activity were evaluated for their activity against visna virus (VV) in sheep choroid plexus (SCP) cells. The activity of several prodrug derivatives against VV proved markedly superior to that of the corresponding free ddN analogues. In particular, the d4A and ddA prodrug derivatives were exquisitely inhibitory in this model system (50% effective concentration [EC50], < or = 0.003 microM), and their anti-VV potency exceeded by at least 200-fold the antiviral potency of the corresponding free nucleosides. Marked differences were noted in the anti-VV potencies of several of the test compounds depending on the nature of the amino acid linked to the 5'-phosphate moiety, the nature of the nucleoside, or both. In view of the stability of the prodrugs in lamb serum, the VV infection model in lambs may be considered highly useful for investigating the in vivo antiretroviral efficacy of these type of drugs, particularly the d4T, ddA, and d4A prodrug derivatives.

Angiocentric cutaneous T-cell lymphoma of childhood (hydroa-like lymphoma): a distinctive type of cutaneous T-cell lymphoma

BACKGROUND

Angiocentric cutaneous T-cell lymphomas of childhood (ACTCLC) are an unusual type of T-cell lymphomas that present with a vesiculopapular eruption mimicking hydroa vacciniforme. Most patients have been children from Asia and Latin America.

OBJECTIVE

The purpose of this study was to describe four cases of ACTCLC; to discuss its clinical, histopathologic, and immunohistochemical features; to consider its possible relationship to the Epstein-Barr virus (EBV); and to clarify its classification within the spectrum of angiocentric lymphomas.

METHODS

The clinical, histopathologic, and immunohistochemical features of four cases of ACTCLC were identified and analyzed. In addition in situ hybridization for EBV was performed in all cases.

RESULTS

The clinical features were similar to previous cases reported under different names, such as hydroa-like lymphomas, edematous, scarring vasculitic panniculitis. Histologically, all showed angiocentric infiltrates composed mainly of T cells. In all cases there were variable numbers of CD30+ cells. The EBV was present in three of the cases.

CONCLUSION

ACTCLC is a distinct type of T-cell lymphoma. It affects mainly children, and the EBV appears to play a role in the pathogenesis of this disease.

Phosphoramidate derivatives of d4T as inhibitors of HIV: the effect of amino acid variation

Phosphoramidate derivatives of the nucleoside analogue, 2',3'-dideoxy-2',3'-didehydro thymidine (d4T) have been prepared as potential membrane-soluble pro-drugs of the big-active free phosphate forms. In particular phenyl phosphates, linked via nitrogen to methyl-esterified amino acids, were studied. All compounds were fully characterised by a range of methods (high-field multinuclear NMR, mass spectrometry and high performance liquid chromatography (HPLC)) and were subjected to in vitro evaluation of their anti-HIV efficacy. The nature of the amino acid appeared to be extremely important for the eventual antiviral action. Of the amino acids studied, L-alanine was the most efficacious, whilst L-proline and glycine were particularly poor. However, an unnatural amino acid moiety, dimethylglycine, could substitute for alanine with little or no loss of activity.