Medicinal chemistry applied to a synthetic protein: development of highly potent HIV entry inhibitors

We have used total chemical synthesis to perform high-resolution dissection of the pharmacophore of a potent anti-HIV protein, the aminooxypentane oxime of [glyoxylyl1]RANTES(2-68), known as AOP-RANTES, of which we designed and made 37 analogs. All involved incorporation of one or more rationally chosen nonnatural noncoded structures, for which we found a clear comparative advantage over coded ones. We investigated structure-activity relationships in the pharmacophore by screening the analogs for their ability to block the HIV entry process and produced a derivative, PSC-RANTES [N-nonanoyl, des-Ser1[L-thioproline2, L-cyclohexylglycine3]-RANTES(2-68)], which is 50 times more potent than AOP-RANTES. This promising group of compounds might be optimized yet further as potential prophylactic and therapeutic anti-HIV agents. The remarkable potency of our RANTES analogs probably involves the unusual mechanism of intracellular sequestration of CC-chemokine receptor 5 (CCR5), and it has been suggested that this arises from enhanced affinity for the receptor. We found that inhibitory potency and capacity to induce CCR5 down-modulation do appear to be correlated, but that unexpectedly, inhibitory potency and affinity for CCR5 do not. We believe this study represents the proof of principle for the use of a medicinal chemistry approach, above all one showing the advantage of noncoded structures, to the optimization of the pharmacological properties of a protein. Medicinal chemistry of small molecules is the foundation of modern pharmaceutical practice, and we believe we have shown that techniques have now reached the point at which the approach could also be applied to the many macromolecular drugs now in common use.     

Persistence of thyroid microsomal and thyroglobulin antigens in primary cultures of human thyroid epithelium

The changes in the amount and distribution of thyroglobulin and thyroid `microsomal' antigens were studied in primary explant and monolayer cultures of human thyroid epithelium which were alive for about 60 days. Both explant and monolayer cultures produced thyroglobulin in vitro at all times during the 60-day period of observation. However, the number of cells containing the thyroid `microsomal' antigen and the amount of antigen in individual cells both diminished though the antigen was detectable in a proportion of viable cells in all cultures at all times during the 60-day period of observation of this report.     

Bionic ear imaging

PURPOSE: The aim of this study was to illustrate the different imaging features of middle and inner ear implants, brainstem implants and inferior colliculus implants. MATERIALS AND METHODS: We retrospectively reviewed the computed tomography (CT) images of 468 patients with congenital or acquired transmissive or neurosensory hearing loss who underwent surgery. The implants examined were: 22 Vibrant Soundbridge implants, 5 at the long limb of the incus and 17 at the round window, 350 cochlear implants, 95 brainstem implants and 1 implant at the inferior colliculus. All patients underwent a postoperative CT scan (single or multislice scanner) and/or a Dentomaxillofacial cone-beam CT scan (CBCT) (axial and multiplanar reconstruction), and/or a plain-film radiography to visualise the correct position of the implant. RESULTS: The CBCT scan depicts Vibrant site of implant better than plain-film radiography, with a lower radiation dose compared to CT. For cochlear implants, a single plain radiograph in the Stenvers projection can directly visualise the electrodes in the cochlea. All patients with brainstem or inferior colliculus implants underwent postoperative CT to exclude complications and the assess correct implantation, but the follow-up of these implants can be performed by plain radiography alone. CONCLUSIONS: CT and CBCT scans are reliable and relatively fast methods for precisely determining the location of middle ear implants. CBCT is preferable to CT because of the lower radiation dose administered; a single plain-film radiograph is enough to visualise and follow-up cochlear, brainstem and inferior colliculus implants.     

Status Epilepticus as Manifestation of Posterior Reversible Encephalopathy Syndrome in a Healthy Child

Posterior reversible encephalopathy syndrome is a recently described cliniconeuroradiological syndrome reported in children with several predisposing conditions such as transplantation, autoimmune, hematological, infectious, renal, and neoplastic diseases or administration of chemotherapeutic immunosuppressive drugs. Seizures are one of the most frequent manifestations of posterior reversible encephalopathy syndrome; status epilepticus has been described more frequently in adults but rarely in children. We report on the case of a 6-year-old healthy boy who presented status epilepticus as the main manifestation of posterior reversible encephalopathy syndrome in the absence of other underlying conditions. This is the first report of posterior reversible encephalopathy syndrome in a previously healthy child. Our case reminds us that pathogenesis of this condition is far from being completely understood and may include both genetic and environmental factors. Moreover, posterior reversible encephalopathy syndrome should always be suspected by clinicians in cases of status epilepticus with a prolonged neurological failure.     

Endovascular Treatment of Diabetic Foot in a Selected Population of Patients with Below-the-Knee Disease: Is the Angiosome Model Effective?

Purpose

To evaluate the efficacy of percutaneous transluminal angioplasty (PTA) in a selected population of diabetic patients with below-the-knee (BTK) disease and to analyze the reliability of the angiosome model.

Methods

We made a retrospective analysis of the results of PTA performed in 201 diabetic patients with BTK-only disease treated at our institute from January 2005 to December 2011. We evaluated the postoperative technical success, and at 1, 6, and 12 months’ follow-up, we assessed the rates and values of partial and complete ulcer healing, restenosis, major and minor amputation, limb salvage, and percutaneous oximetry (TcPO₂) (Student’s t test). We used the angiosome model to compare different clinicolaboratory outcomes in patients treated by direct revascularization (DR) from patients treated with indirect revascularization (IR) technique by Student’s t test and the χ² test.

Results

At a mean ± standard deviation follow-up of 17.5 ± 12 months, we observed a mortality rate of 3.5 %, a major amputation rate of 9.4 %, and a limb salvage rate of 87 % with a statistically significant increase of TcPO₂ values at follow-up compared to baseline (p < 0.05). In 34 patients, treatment was performed with the IR technique and in 167 by DR; in both groups, there was a statistically significant increase of TcPO₂ values at follow-up compared to baseline (p < 0.05), without statistically significant differences in therapeutic efficacy.

Conclusion

PTA of the BTK-only disease is a safe and effective option. The DR technique is the first treatment option; we believe, however, that IR is similarly effective, with good results over time.     

Pneumolabyrinth and positional vertigo after stapedectomy

Pneumolabyrinth due to late complications of stapes surgery is a rare entity. Symptoms may include various degrees of hearing loss, tinnitus and dizziness. We report the case of a 67-year-old patient who developed a unique pneumolabyrinth variant affecting the vestibule, cochlea and semicircular canals 28 years after stapedectomy. The patient presented with intractable paroxysmal positional vertigo of the lateral semicircular canal. The pneumolabyrinth was visualized by means of high resolution computed tomography. Exploratory tympanotomy findings were consistent with a perilymphatic fistula. One year after surgical treatment the subject was free of vertigo spells. Pathogenetic mechanisms are discussed.     

Diagnostic accuracy of lung ultrasonography combined with procalcitonin for the diagnosis of pneumonia: a pilot study

Background

The diagnostic value of lung ultrasonography (LUS) and procalcitonin (PCT) in the diagnosis of lung infections is known. No studies evaluated the combination of LUS and PCT for the diagnosis of pneumonia in the emergency department (ED). We evaluated the diagnostic accuracy of the combination of LUS and PCT in the diagnosis of pneumonia.

Methods

Patients with respiratory symptoms of unexplained origin who underwent a chest CT in ED were included in the study if PCT assay was available. LUS was performed before CT and was targeted to the detection of lung consolidations with the morphologic features of pneumonia. A PCT assay was performed at presentation, and cut-off of 0.25 and of 0.5 ng/ml were used to rule-out and rule-in pneumonia. The final diagnosis of pneumonia was established by independent clinicians, on the basis of clinical chart review including CT results.

Results

We enrolled 128 patients and pneumonia was the final diagnosis in 61 (47.7%). In 38 patients (29.7%) LUS and PCT were negative (PCT < 0.25 ng/ml). The overall accuracy, sensitivity and negative predictive value of LUS/PCT were 88.8, 96.7 and 94.7% respectively. Sensitivity of the LUS/PCT test was significantly superior to LUS alone (85.2%) and PCT alone (73.8%) (p < 0.05 for both). Specificity and positive predictive value of the combination of positivity of LUS/PCT (PCT > 0.5 ng/ml) were 94% and 83.3% respectively. Specificity of LUS/PCT was not significantly different to LUS alone (88.1%) (p = 0.125).

Conclusions

The sensitivity of the combination of LUS with PCT for the diagnosis of pneumonia was significantly superior when compared with the sensitivity of LUS and PCT alone.