Development of 3D-QSAR and pharmacophoric models to design new anti-Trypanosoma cruzi agents based on 2-aryloxynaphthoquinone scaffold

In this work we have collected a set of 30 trypanosomicidal naphthoquinones and developed pharmacophoric and 3D-QSAR models as tools for the design of new potential anti-Chagasic compounds. Firstly, qualitative information was obtained from SAR and pharmacophoric models identifying some fragments around the 2-aryloxynaphthoquinone scaffold important for the antiparasitic activity. Then, 3D-QSAR CoMFA and CoMSIA models were developed. The models showed adequate statistical parameters where the steric, electrostatic, and hydrophobic features explain the trypanosomicidal effect. Therefore, to validate our models, we carried out the design, synthesis, and biological evaluation on T. cruzi epimastigotes of five new compounds (33a-e). According to CoMFA model, three out of five compounds showed pIC₅₀ values within one logarithmic unit of deviation. The two compounds that did not fit the predictions were those with high lipophilicity, which agreed with the SAR and pharmacophore models. Docking and molecular dynamic studies were performed on T. cruzi trypanothione reductase, in a proposed binding site for this type of naphthoquinone. Interestingly, 33a-e showed the same interaction pattern as a naphthoquinone inhibitor (2). Finally, predicted drug-likeness properties indicated that 33a-e have optimal oral bioavailability. Thus, this study provides new in silico models for obtaining novel trypanosomicidal compounds.

Percutaneous cervical nucleoplasty using coblation technology. Clinical results in fifty consecutive cases

Conventional open cervical discectomy, with or without bony fusion, in common neurosurgical knowledge is considered the standard treatment for cervical disc herniation. Percutaneous procedures are minimally invasive and offer decreased morbidity, require no bone graft and promise shorter recuperation time. Nevertheless, candidates for a percutaneous procedure as inclusion criteria must complain of symptoms related to contained herniated disc or focal protrusion. It does not substitute conventional open procedures required for extruded discs. We used the coblation technology for nucleoplasty of the cervical intervertebral discs. Early and long-term effects and/or complications observed with this procedure have not been reported yet. Fifty consecutive patients presenting with contained herniated cervical disc or focal protrusion causing compression of the cervical roots or cervical pain underwent a nucleoplasty procedure on the pathological disc. A randomized control group of twenty patients was treated conservatively with medical and physical therapy in the same period and completed the identical follow-up form. In the nucleoplasty group results were complete resolution of symptoms in 80% of cases, only 10% referred some residual cervical or radicular pain and are still under follow-up with a wait-and-see prospective. Patients who did not have a clinical resolution were treated with alternative traditional methods (10%). Despite the relative low cases number and the limited follow-up the encouraging results induce us to utilize this technique in well-selected cases.

Hypoflow and hyperflow in diffuse axonal injury. Prognostic and therapeutic implications of transcranial Doppler sonography evaluation

BACKGROUND

In the present report we describe the results of a study aimed at evaluating the cerebral haemodynamics and the neuroradiological findings observ-ed in 7 consecutive patients, 4 adults and 3 children (6, 8 and 10 years old), affected by diffuse axonal injury (DAI).

METHODS

All the patients were admitted to the Paediatric or Adult Intensive Care Unit with GCS scores less than 8 after a severe brain injury. Serial head CT scan and trans-cranial Doppler sonography (TCD) examinations were carried out in all patients; MRI was carried out in the paediatric patients only. TCD of the middle cerebral arteries was performed through the temporal bone window. In 6 cases (2 paediatric) diuretic osmotic therapy was immediately administered and in 6 cases (3 paediatric) barbiturates and hyperventilation were also used.

RESULTS

Hyperflow, variably responsive to barbiturate therapy of vasoparalysis, was observed in all paediatric patients and in 3 adult subjects (85.7%: 6 out of 7 pa-tients) by means of TCD.

CONCLUSIONS

Observation of these phenomena allowed us to modify the pharmacological treatment and/or perform external cerebrospinal fluid (CSF) drainage (4 cases). Compartimental hyperflow TCD pattern was evident in 1 patient. Although the limited number of patients in our series does not allow definitive conclusions, we strongly believe that TCD monitoring is an useful tool in planning surgical strategy in patients with DAI.

Spinal cord stimulation and early experimental cerebral spasm: the "functional monitoring" and the "preventing effect"

BACKGROUND

Clinical and experimental data on cerebral blood flow (CBF) changes during spinal cord stimulation (SCS) were published since 1986. The aims of the present work are: 1. To find an experimental model of reliable, simple and in vivo monitoring of "early" basilar artery spasm after subarachnoid haemorrhage (SAH) and 2. To investigate the effects of cervical spinal cord stimulation (CSCS) on it. Vasospasm due to SAH is both "acute" and "recurrent". Early spasm occurs within minutes of the SAH. its duration is approximately 1 hour. The need of different morphological and haemodynamic methods to evaluate experimental early spasm is reported. To overcome intracranial surgical manipulations and biological effects of contrast and fixation media we designed a model that allows "in vivo" functional monitoring of basilar blood flow far away from the spasm without direct surgical and chemical interference. Subsequently we investigated the effects of CSCS on the new model of "functional monitoring" of the "early" cerebral vasospasm.

METHOD

29 adult Burgundy rabbits were studied. Group 1: under homeostatic monitoring, "on-line" carotid blood flow (carotid BF) changes produced by SAH in cisterna magna of 12 (plus 5 sham treated) animals were studied from the common carotid artery after external carotid artery occlusion before, during SAH and up to the end of the experiments. All the animals underwent digital subtraction cerebral panangiography (CPA) after SAH obtaining a significant increase of carotid BF only when basilar vasospasm was shown by CPA. Carotid BF increase during basilar vasospasm was defined "functional monitoring" of early spasm. Group 2: Twelve animals wearing a cervical epidural electrode underwent carotid BF "functional monitoring" of early basilar spasm before and during CSCS.

FINDINGS

Carotid BF changes during CSCS occurred in 10 animals. No carotid BF changes (i.e. no basilar vasospasm) occurred after SAH up to the end of the experiments in all the stimulated animals.

INTERPRETATION

CSCS is able to prevent "early spasm" due to SAH in all the animals studied with the new model of "functional monitoring" described, independently from the occurence and the sign for stimulation-induced carotid BF variations. The role and the limits of reversible functional sympathectomy in mediating the effect of CSCS on early vasospam are discussed.

Craniopharyngiomas of the third ventricle: trans-lamina terminalis approach

OBJECTIVE

Craniopharyngiomas usually grow on the cisternal surface of the hypothalamic region; these tumors can also grow from the infundibulum or tuber cinereum on the floor of the third ventricle, developing exclusively into the third ventricle. The aim of the present work was to establish the usefulness of the pterional trans-lamina terminalis approach for the removal of these tumors.

METHODS

Eight patients who were surgically treated for craniopharyngiomas located exclusively within the third ventricle were considered. The initial symptoms were acute hydrocephalus in two cases, psychological disturbances in two, amenorrhea in two, headaches in one, and hypopituitarism in one. The diagnoses were established, in all cases except one, with magnetic resonance imaging. In all cases, the tumor completely filled the third ventricle.

RESULTS

Total removal of the lesion was achieved in seven cases. One patient underwent partial removal. In the immediate postoperative period, no major complications were observed. Five patients required replacement hormonal therapy. All patients returned to a normal life. Many months after surgery, two patients exhibited psychological disturbances and died, the first because of voluntary withdrawal of replacement therapy (12 mo after surgery) and the second because of a severe imbalance in body fluids and electrolytes, with a subsequent hyperosmolar coma (27 mo after surgery). Only one patient who underwent initial total removal experienced a small recurrence of the lesion (30 mo after surgery); after 3 years, the lesion exhibited unchanged size.

CONCLUSION

In our experience, the trans-lamina terminalis approach is a valid choice for the removal of purely intraventricular craniopharyngiomas. These tumors can be removed without significant sequelae related to the surgical approach. The proximity to the hypothalamus requires accurate neuroendocrine and electrolyte control in the postoperative period, in some cases even years after surgery.