Modified endoscopic strip craniectomy technique for sagittal craniosynostosis: provides comparable results and avoids bony defects.

PURPOSE: This study describes a modified technique addressing bony defects and incomplete ossification after endoscopic strip craniectomy (ESC) for SC followed by postoperative helmet therapy (PHT). The study aims to delineate quantitative and qualitative outcomes of this modified ESC technique followed by PHT and discern the optimal duration of PHT following ESC. A secondary aim is to address the effects of the technique on bony defects. METHODS: Patients undergoing ESC followed by PHT between 2017 and 2021 were included. Patient sex, age at surgery, duration of surgery, red blood cell transfusion, length of hospital stay, PHT duration, cephalic index (CI) at multiple time points, and bony defect information were collected. Descriptive and correlative analysis was done. RESULTS: Thirty-one patients (25 male, 6 female) were operated in study period. Mean age at surgery was 12.81 weeks, mean duration of surgery was 57.50 min, average transfused RBC volume was 32 cc, mean length of hospital stay was 1.84 days, mean PHT duration was 33.16 weeks, and mean follow-up time was 63.42 weeks. Mean preoperative CI was 70.6, and mean CI at the end of PHT was significantly higher, being 77.1. Maximum improvement in CI (CImax) took place at week 22.97. PHT duration did not have a correlation with CI at last follow up. There were no bony defects. CONCLUSION: Modified ESC technique is effective in successful correction of sagittal craniosynostosis. CImax already takes place, while PHT is continuing, but there is no certain time point for dishelmeting. The technique avoided bony defects and incomplete ossification.

The role of age on helmet therapy in deformational plagiocephaly and asymmetric brachycephaly.

PURPOSE: This study aimed to investigate the effect of age at helmet therapy onset on treatment efficacy in moderate-to-severe deformational plagiocephaly (DP) and combined DP and asymmetrical brachycephaly (AB) in infants. METHODS: Ninety-eight infants who were referred to our institution and who underwent helmet therapy between 2014 and 2018 were retrospectively reviewed. Patients with DP [cranial vault asymmetry index (CVAI) > 7% and DD > 10 mm] and AB [CVAI > 7% and cephalic ratio (CR) ≥ 94] were included. Pre- and post-treatment calvarial asymmetries (difference among DD, CVAI, and CR) were measured using 3D screening systems (SmartSoc and Omega Scanner 3D). Infants were classified according to age at treatment onset: group 1 (age, < 6 months) and group 2 (age, ≥ 6 months). RESULTS: CVAI was statistically different between treatment onset and end in subgroups. Moreover, the regression of CVAI between groups DP1 (- 7.5% ± 1.2%) versus DP2 (- 5.4% ± 1.5%; p = 0.001) and groups AB1 (- 6.6% ± 1.4%) versus AB2 (- 4.4 ± 2.5; p = 0.0013) was statistically significant. CVAI was < 3.5% and CR was ≤ 89 (assumed as normal cranial shape) after treatment in 48%, 40%, 32%, and 6% of infants in groups DP1, DP2, AB1, and AB2, respectively. CONCLUSION: These findings emphasize the efficacy of helmet therapy for DP and AB. Helmet is an appropriate treatment option particularly for infants with severe DP and AB, and early onset of helmet therapy before the age of 6 months is advised.

Radiofrequency Thermocoagulation of the Ganglion Impar for Coccydynia Management: Long-Term Effects.

OBJECTIVE: To investigate the short- and long-term effects of ganglion impar radiofrequency thermocoagulation (RFT) treatment in patients with chronic coccydynia. METHODS: We retrospectively analyzed the medical records of patients who underwent RFT of the ganglion impar between 2009 and 2011. Pain intensity visual numeric scale (VNS) scores and Euroqol 5D (EQ-5D) index scores were recorded pre-intervention and post-intervention at the first, sixth, and twelfth months. The differences between pre-procedural VNS scores and post-procedural VNS scores at the first, sixth, and twelfth months were evaluated. The success of the intervention was recorded as the percentage difference between the pre-intervention VNS scores and post-intervention VNS scores at the first, sixth, and twelfth months. RESULTS: The mean age of the patients, including 11 females (55%) and 8 males (45%), was 48.7 ± 14.3 years. The average follow-up duration was 17.3 ± 2.9 months. Statistically significant differences were observed between the pre- and post-procedure VNS scores (P < 0.0001). Improvements in VNS scores were correlated with improvements in EQ-5D index scores. Mid-term (sixth month) and long-term (twelfth month) evaluations after the intervention revealed that 67.4% and 61.1% of the patients had successful outcomes, respectively. CONCLUSION: Our data suggested that RFT of the ganglion impar in patients with chronic coccydynia resulted in effective outcomes, and patients who responded to RFT had significantly lower post-RFT pain scores.

A clinical scoring system to predict the development of intraventricular hemorrhage (IVH) in premature infants.

OBJECTiVE: The aim of this study is to develop a scoring system for the prediction of intraventricular hemorrhage (IVH) in preterm infants in the first 7 days of life. METHODS: A prospective, clinical study was conducted in Bahcesehir University, Medical Park Goztepe Hospital Neonatal Intensive Care Unit, with the enrollment of 144 preterm infants with gestational age between 24 and 34 weeks. All preterms were followed up for IVH after birth until the 4th week of life. The demographic characteristics and clinical risk factors were noted. Risk factors were analyzed. The score was established after logistic regression analysis, considering the impact of each variable on the occurrence of IVH within the first 7 days of life. The IVH scores were further applied prospectively to 89 preterm infants as validation cohort. RESULTS: Low gestational age (GA), low Apgar score, and having bleeding diathesis were the most important risk factors for IVH. According to these risk factors, a scoring system was developed for IVH ranged from 0 to 5. According to the risk ratios (RR) obtained from the logistic regression model, low GA (≤ 28 gestational week), presence of bleeding diathesis within 7 days, and low Apgar score increased the risk of IVH (RR = 3.32 for GA ≤ 28 gestational week, RR = 6.7 for presence of bleeding diathesis in 7th day, RR = 3 for having low Apgar score). The score was validated successfully in 89 infants. The area under ROC curve was 0.85 for derivation cohort and 0.807 for validation cohort. The predictive ability of the IVH score for derivation and validation cohort was calculated. The negative predictive values of a score less than 4 were 96.4 and 59.1%. CONCLUSiON: Concerning IVH-related sequelae which continue to be a major public health problem, we have developed a feasible predictive model for evaluating the risk for developing IVH for preterm infants in the first 7 days of life.

Epithelial Cell Transforming 2 and Aurora Kinase B Modulate Formation of Stress Granule-Containing Transcripts from Diverse Cellular Pathways in Astrocytoma Cells.

Stress granules are small RNA-protein granules that modify the translational landscape during cellular stress to promote survival. The RhoGTPase RhoA is implicated in the formation of RNA stress granules. Our data demonstrate that the cytokinetic proteins epithelial cell transforming 2 and Aurora kinase B (AurkB) are localized to stress granules in human astrocytoma cells. AurkB and its downstream target histone-3 are phosphorylated during arsenite-induced stress. Chemical (AZD1152-HQPA) and siRNA inhibition of AurkB results in fewer and smaller stress granules when analyzed using high-throughput fluorescent-based cellomics assays. RNA immunoprecipitation with the known stress granule aggregates TIAR and G3BP1 was performed on astrocytoma cells, and subsequent analysis revealed that astrocytoma stress granules harbor unique mRNAs for various cellular pathways, including cellular migration, metabolism, translation, and transcriptional regulation. Human astrocytoma cell stress granules contain mRNAs that are known to be involved in glioma signaling and the mammalian target of rapamycin pathway. These data provide evidence that RNA stress granules are a novel form of epigenetic regulation in astrocytoma cells, which may be targetable by chemical inhibitors and enhance astrocytoma susceptibility to conventional therapy, such as radiation and chemotherapy.

Bilateral Central Foot Drop in a Pediatric Patient.

Foot drop is an inability to dorsiflex the ankle and toe. Primary causes of foot drop are compression or lesion of the 5th lumbar nerve and entrapment of the peroneal nerve at the head of the fibula. Rarely, some central nervous system lesions lead to foot drop. A 16-year-old boy was admitted with blunt head trauma that had happened in an assault. The muscle strength of the bilateral tibialis anterior, bilateral extensor digitorum longus and bilateral extensor digitorum brevis were Medical Research Council grade 1. Deep tendon reflexes of both ankles were hyperactive, with bilateral clonus and bilateral Babinski sign. There were cerebral contusions with peripheral edema in both motor strip areas extending anteriorly into the frontal lobes, with right-sided epidural-subdural hematoma. On brain MRI, the superior sagittal sinus was open. The epidural-subdural hematoma did not progress in its dimensions. The patient was treated conservatively. He recovered fully with regression of the contusions and epidural-subdural hematoma 4 months after the trauma. Foot drop due to upper motor neuron pathologies is more spastic in nature, different from what happens following lumbar disc herniation or peroneal nerve dysfunction. Treatment of central foot drop should be planned according to the underlying pathology.

Microsurgical removal of craniopharyngioma: endoscopic and transcranial techniques for complication avoidance.

Craniopharyngioma remains a challenging entity for neurosurgeons because of its midline, deep seated location and intimate relationship with critical neurovascular structures. Although gross total resection is ideal, the need to reduce surgical morbidity and preserve quality of life has led to a number of neurosurgical approaches which have attained this goal. Here we discuss the commonly used approaches for surgical resection and highlight technical considerations to reduce the potential of complications. We also discuss the mutually exclusive underlying genetic lesions in different histopathological subtypes that will likely lead to future treatment options for these tumors.

Medulloblastoma: Tumor Biology and Relevance to Treatment and Prognosis Paradigm.

Medulloblastoma is a malignant embryonic brain tumor arising in the posterior fossa and typically occurring in pediatric patients. Current multimodal treatment regimes have significantly improved the survival rates; however, a marked heterogeneity in therapy response is observed, and one third of all patients die within 5 years after diagnosis. Large-scale genetic and transcriptome analysis revealed four medulloblastoma subgroups (WNT, SHH, Group 3, and Group 4) associated with different demographic parameters, tumor manifestation, and clinical behavior. Future treatment protocols will integrate molecular classification schemes to evaluate subgroup-specific intensification or de-escalation of adjuvant therapies aimed to increase tumor control and reduce iatrogenic induced morbidity. Furthermore, the identification of genetic drivers allows assessing target therapies in order to increase the chemotherapeutic armamentarium. This review highlights the biology behind the current classification system and elucidates relevant aspects of the disease influencing forthcoming clinical trials.

Dithiocarbamates with potent inhibitory activity against the Saccharomyces cerevisiae ß-carbonic anhydrase.

Dithiocarbamates (DTCs) prepared from primary or secondary amines, which incorporated amino/hydroxyl-alkyl, mono-/bicyclic aliphatic/heterocyclic rings based on the quinuclidine, piperidine, hydroxy-/carboxy-/amino-substituted piperidine, morpholine and piperazine scaffolds, were investigated for the inhibition of α- and ß-carbonic anhydrases (CAs, EC 4.2.1.1) of pharmacologic relevance, such as the human (h) isoform hCA I and II, as well as the Saccharomyces cerevisiae ß-CA, scCA. The yeast and its ß-CA were shown earlier to be useful models of pathogenic fungal infections. The DTCs investigated here were medium potency hCA I inhibitors (K(I)s of 66.5-910 nM), were more effective as hCA II inhibitors (K(I)s of 8.9-107 nM) and some of them showed excellent, low nanomolar activity against the yeast enzyme, with inhibition constants ranging between 6.4 and 259 nM. The detailed structure activity relationship for inhibition of the yeast and human enzymes is discussed. Several of the investigated DTCs showed excellent selectivity ratios for inhibiting the yeast over the human cytosolic CA isoforms.

Kinetic and docking studies of cytosolic/tumor-associated carbonic anhydrase isozymes I, II and IX with some hydroxylic compounds.

A series of hydroxylic compounds (1-10, NK-154 and NK-168) have been assayed for the inhibition of three physiologically relevant carbonic anhydrase isozymes, the cytosolic isozymes I, II and tumor-associated isozyme IX. The investigated compounds showed inhibition constants in the range of 0.068-4003, 0.012-9.9 and 0.025-115 µm at the hCA I, hCA II and hCA IX enzymes, respectively. In order to investigate the binding mechanisms of these inhibitors, in silico studies were also applied. Molecular docking scores of the studied compounds are calculated using scoring algorithms, namely Glide/induced fit docking. The inhibitory potencies of the novel compounds were analyzed at the human isoforms hCA I, hCA II and hCA IX as targets and the KI values were calculated.

Magnetically Controlled Growing Rod in Early-Onset Scoliosis: A Minimum of 2-Year Follow-Up.

PURPOSE: The magnetically controlled growing rod technique decreases complications, costs, and loss of functionality by avoiding successive surgical corrections every 6 months in patients with early-onset scoliosis. However, only a few studies have presented clinical experience with the magnetically controlled growing rod. In this study we aimed to present our single-center experience in patients with early-onset scoliosis who underwent the magnetically controlled growing rod technique and follow-up for at least 2 years. MATERIALS AND METHODS: We made an observational study by evaluating patients with early-onset scoliosis who underwent the magnetically controlled growing rod technique between February 2012 and December 2013. Demographic and clinical data were obtained from the patients charts. We included patients who were followed up for at least 2 years. Radiological data were obtained from plain anterior-posterior and lateral scoliosis X-rays. RESULTS: Eight patients with early-onset scoliosis who underwent surgery using the magnetic system were treated with dual rods. None of the spines were fused to the sacrum. We observed no intra- and/or postsurgical complications. The average number of external rod lengthenings was 7.6. The average amount of lengthening was 30.6 mm on the right side and 27.8 mm on the left side by the time of last clinical follow-up. The average coronal and sagittal Cobb values at the final clinical evaluation were 10.5° (thoracic coronal), 13.75° (lumbar coronal), 6.25° (lumbosacral coronal), 24.5° (thoracic sagittal), and 40° (lumbar sagittal), respectively. CONCLUSIONS: The magnetically controlled growing rod is beneficial in early-onset scoliosis, since it enables spinal growth and decreases additional surgeries, complications, and costs. Even though we had a small sample size, our follow-up period was enough to declare long-term outcomes of our patients. Multicenter and large sample-sized studies are needed to make more conclusive statements regarding this promising scoliosis treatment approach.

Trigeminal Neuralgia Caused by Cerebellopontine Angle Arteriovenous Malformation Treated With Gamma Knife Radiosurgery.

Trigeminal neuralgia is a facial pain syndrome characterized as sudden onset and lightening-like sensation over somatosensorial branch(es) of fifth cranial nerve. Rarely, some underlying diseases or disorders could be diagnosed, such as multiple sclerosis, brain tumors, and vascular malformations. The authors present a 47-year-old man with trigeminal neuralgia over left V2 and V3 dermatomes. He had a previous transarterial embolization and long use of carbamazepine with partial response to treatment. Gamma knife radiosurgery (GKR) was planned. A marginal dose of 15 Gy was given to 50% isodose line. His pain was relieved by GKR in 1.5 years. Treatment of posterior fossa arteriovenous malformations causing trigeminal neuralgia, with GKR has a very limited use in the literature. It, however, is obvious that success rate as pain relief, in a very challenging field of functional neurosurgery, is satisfactory. Large series, however, are in need to make a more comprehensive statement about efficacy and safety of the procedure in these pathologies.

Delayed Onset Intracranial Subdural Hematoma Following Spinal Surgery.

In this case-based review, the authors analyzed relevant literature with an illustrative patient of theirs about subdural hematoma secondary to dural tear at spinal surgery. Intracranial hypotension is a condition of decreased cerebrospinal fluid volume and pressure. Even though intracranial hypotension is temporary and can be managed conservatively, it may progress and result in subdural fluid collections, hematoma formations, "brain sagging or slumping" states, syringohydromyelia, encephalopathy, coma, and even death. The authors present an 81-year-old man admitted with subdural hematoma 50 days following previous spinal surgery for lumbar spinal stenosis. In his previous spinal surgery he had had dural tear, which had been closed primarily. To the literature, only 21 patients have been reported to develop subdural hematoma following spinal surgery. In patients with subdural hematoma following spinal surgery, the female:male ratio was 3:4 and the median age was 55 years. Surgical diagnoses for previous spinal surgeries were intervertebral disc herniation (5), spinal canal stenosis and spondylolisthesis (6), failed back syndrome (2), tethered cord syndrome and myelodysplastic spine (2), spinal cord tumor, spinal epidural hematoma, vertebral dislocation, vertebral fracture, vertebral tumor, and inflammatory spine. Patients presented with signs and symptoms of subdural hematoma within 6 hours to 50 days following the spinal surgery. Source of cerebrospinal fluid leak was most commonly from lumbar region (13 patients, 62%). Ten of 21 (48%) patients were treated conservatively. Late-onset neurological findings should not prevent the evaluation of cranial vault with computed tomography and magnetic resonance imaging. Spinal dural tear should be more aggressively treated instead of suture alone approach, when recognized in older patients during the spinal surgery.

Interaction of carbonic anhydrase isozymes I, II, and IX with some pyridine and phenol hydrazinecarbothioamide derivatives.

A series of hydrazinecarbothioamide derivatives incorporating ethyl, phenyl, tolyl, benzyl, and allyl moieties were prepared and tested as possible inhibitors of three members of the pH regulatory enzyme family, carbonic anhydrase (CA; EC 4.2.1.1). The inhibitory and activatory potencies of the compounds against the cytosolic human isoforms hCA I and hCA II and the transmembrane, tumor-associated hCA IX were analyzed by a hydrase assay with CO2 as substrate, and the inhibition constants (KI) were calculated. Most compounds investigated here exhibited nanomolar or low micromolar inhibition constants against the three isoenzymes. KI values were in the range of 34.1-871 nM for hCA I and compounds 5-10 showed interesting activation of the hCA II with KA value of 0.81-12.5 µM. Compounds 11-16 exhibited moderate inhibition effects on hCA IX in the range of 0.317-1.245 µM but they were less effective for hCA II. Tested compounds were also investigated using in silico applications at the binding pockets of these three targets. The different mechanisms of inhibition by these tested compounds as compared to sulfonamides, and their diverse inhibition profile for these mammalian isozymes, makes this class of derivatives of great interest for the design of novel CA inhibitors.

Sulfonamide inhibition study of the ß-class carbonic anhydrase from the caries producing pathogen Streptococcus mutans.

Streptococcus mutans, the oral pathogenic bacterium provoking dental caries formation, encodes for a ß-class carbonic anhydrase (CA, EC 4.2.1.1), SmuCA. This enzyme was cloned, characterized and investigated for its inhibition profile with the major class of CA inhibitors, the primary sulfonamides. SmuCA has a good catalytic activity for the CO2 hydration reaction, with a kcat of 4.2×10(5) s(-1) and kcat/Km of 5.8×10(7) M(-1)×s(-1), and is efficiently inhibited by most sulfonamides (KIs of 246 nM-13.5 µM). The best SmuCA inhibitors were bromosulfanilamide, deacetylated acetazolamide, 4-hydroxymethylbenzenesulfonamide, a pyrimidine-substituted sulfanilamide derivative, aminobenzolamide and compounds structurally similar to it, as well as acetazolamide, methazolamide, indisulam and valdecoxib. These compounds showed inhibition constants ranging between 246 and 468 nM. Identification of effective inhibitors of this enzyme may lead to pharmacological tools useful for understanding the role of S. mutans CAs in dental caries formation, and eventually the development of pharmacological agents with a new mechanism of antibacterial action.

Cloning, characterization and anion inhibition study of a ß-class carbonic anhydrase from the caries producing pathogen Streptococcus mutans.

The oral pathogenic bacterium involved in human dental caries formation Streptococcus mutans, encodes for two carbonic anhydrase (CA, EC 4.2.1.1) one belonging to the α- and the other one to the ß-class. This last enzyme (SmuCA) has been cloned, characterized and investigated for its inhibition profile with a major class of CA inhibitors, the inorganic anions. Here we show that SmuCA has a good catalytic activity for the CO2 hydration reaction, with kcat 4.2×10(5)s(-1) and kcat/Km of 5.8×10(7)M(-1)×s(-1), being inhibited by cyanate, carbonate, stannate, divannadate and diethyldithiocarbamate in the submillimolar range (KIs of 0.30-0.64mM) and more efficiently by sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid (KIs of 15-46µM). The anion inhibition profile of the S. mutans enzyme is very different from other α- and ß-CAs investigated earlier. Identification of effective inhibitors of this new enzyme may lead to pharmacological tools useful for understanding the role of S. mutans CAs in dental caries formation, and eventually the development of pharmacological agents with a new mechanism of antibacterial action.

Synthesis of a new series of dithiocarbamates with effective human carbonic anhydrase inhibitory activity and antiglaucoma action.

A new series of dithiocarbamates (DTCs) was prepared from primary/secondary amines incorporating amino/hydroxyl-alkyl, mono- and bicyclic aliphatic ring systems based on the quinuclidine, piperidine, hydroxy-/carboxy-/amino-substituted piperidine, morpholine and piperazine scaffolds, and carbon disulfide. The compounds were investigated for the inhibition of four mammalian α-carbonic anhydrases (CAs, EC 4.2.1.1) of pharmacologic relevance, that is, the human (h) hCA I, II, IX and XII, drug targets for antiglaucoma (hCA II and XII) or antitumor (hCA IX/XII) agents. The compounds were moderate or inefficient hCA I inhibitors (off-target isoform for both applications), efficiently inhibited hCA II, whereas some of them were low nanomolar/subnanomolar hCA IX/XII inhibitors. One DTC showed excellent intraocular pressure (IOP) lowering properties in an animal model of glaucoma, with a two times better efficiency compared to the clinically used sulfonamide dorzolamide.

Synthesis of a novel affinity gel for the purification of carbonic anhydrases.

A new affinity gel was synthesized for the purification of carbonic anhydrase (CA, EC 4.2.1.1) isozymes from erythrocytes. The gel was prepared on a Sepharose 4B matrix on which a spacer arm based on ethylenediamine was covalently attached via CNBr activation, followed by reaction with the CA inhibitor 4-isothiocyanato-benzenesulfonamide. The derivatized gel incorporated thioureido-benzenesulfonamide moieties as CA ligand. The binding capacity of the new affinity gel was determined at different temperatures, pH values, ionic strengths and elution buffers. The maximum binding of various CAs was achieved at 25 °C with pH 8.5 and ionic strength around 0.4. The overall purifications for human (h) hCA I and hCA II were 672- and 580-fold, and with 62 and 43% yields, respectively. SDS-polyacrylamide gel electrophoresis showed single bands for each purified isozymes, corresponding to a molecular weight of approx. 29 kDa. This is an easily obtainable, efficient and robust affinity gel, useful for the purification of many other α-CAs.

A new affinity gel for the purification of α-carbonic anhdrases.

The new affinity gel reported in this study was prepared using EUPERGIT C250L as a chromatographic bed material, to which etylenediamine spacer arms were attached to prevent steric hindrance between the matrix and ligand, and to facilitate effective binding of the CA-specific ligand, of the aromatic sulfonamide type for the purification of α-carbonic anhydrases (Cas; EC 4.2.1.1). Indeed, the aminoethyl moieties of the affinity gel were derivatized by reaction with 4-isothiocyanatobenzenesulfonamide, with the formation of a thiourea-based gel, having inhibitory effects against CAs. Both bovine erythrocyte carbonic anhydrase BCA and human (h) erythrocyte CA isoforms I, II (hCA I and II) have been purified from hemolysates, by using this affinity gel. The greatest purification fold and column yields for BCA and for cytosolic (hCA I + II) enzymes were of 181-fold (21.07%) and 184-fold (9.49%), respectively. Maximum binding was achieved at 15 °C and I = 0.3 ionic strength for α-carbonic anhydrases.

7-Amino-3,4-dihydro-1H-quinolin-2-one, a compound similar to the substituted coumarins, inhibits α-carbonic anhydrases without hydrolysis of the lactam ring.

7-Amino-3,4-dihydro-1H-quinolin-2-one, a compound structurally similar to coumarins, recently discovered class of inhibitors of the α-carbonic anhydrases (CAs, EC 4.2.1.1) was investigated for its interaction with all human (h) CA isoforms, hCA I-XIV. The compound was not an inhibitor of the cytosolic, widespread isoform hCA II (K(I) > 10 µM), was a weak inhibitor of hCA I, III, IV, VA, VI and XIII (K(I)s in the range of 0.90-9.5 µM) but effectively inhibited the cytosolic isoform hCA VII (K(I) of 480 nM) as well as the transmembrane isoforms hCA IX, XII and XIV (K(I)s in the range of 16.1-510 nM). Against many CA isoforms this lactam was a better inhibitor compared to the structurally similar 4-methyl-7-aminocoumarin, but unlike this compound, the lactam ring was not hydrolyzed and the inhibition was due to the intact bicyclic amino-quinolinone scaffold. Bicyclic lactams strucurally related to coumarins are thus a new class of CA inhibitors possessing however a distinct inhibition mechanism compared to the coumarins which undergo a hydrolysis of their lactone ring for generating the enzyme inhibitory species.