Incidence of ocular side effects with intravenous zoledronate: secondary analysis of a randomized controlled trial.

SUMMARY: This prospective study showed that the incidence of acute anterior uveitis, confirmed by ophthalmic examination, in patients receiving intravenous zoledronate infusions as part of a randomized controlled trial for fracture prevention is 1.1%. INTRODUCTION: We prospectively investigated the incidence of ocular side effects after a single intravenous zoledronate infusion. METHODS: In a secondary analysis of a double-blind, placebo-controlled trial in which early post-menopausal women (N=1054) with normal bone density or osteopenia were randomized to infusion of zoledronate 5 mg (N=703) or placebo (N=351), we analyzed significant adverse ocular events occurring within 3 months. RESULTS: Fourteen participants reported ocular symptoms after the infusion. All were examined by an ophthalmologist and eight were diagnosed with acute anterior uveitis (AAU) and one with sectoral episcleritis. The incidence of AAU and episcleritis was 1.1% (95% CI 0.5-2.1) and 0.1% (95% CI 0.0-0.7), respectively, in the zoledronate group and 0% for both conditions in the placebo group (95% CI 0.0-0.8). The mean time from infusion to symptom onset for AAU was 3 days (range 2-4). Three cases were bilateral. AAU was mild-moderate in seven participants and severe in one. All affected eyes were treated with topical cyclopentolate 1% (to break, or minimize, posterior synechiae), and intensive, potent, topical corticosteroids with a tapering regime based on treatment response. The mean duration of topical corticosteroid was 26±10 days (range 17-44). The mean, best corrected visual acuity was 20/20 (range 20/20-20/40) at presentation, which remained unchanged after AAU resolution. None of the participants lost vision, and no long-term sequelae were reported at last follow-up (range 3-13 months post-infusion). CONCLUSIONS: Prescribers should inform patients about the possibility of ocular side effects with zoledronate infusions and refer promptly to an ophthalmologist if symptoms develop.

Bacterial Peptide deformylase inhibitors: a new class of antibacterial agents.

Peptide deformylase (PDF) is a prokaryotic metalloenzyme that is essential for bacterial growth but is not required by mammalian cells. Thus, it represents a selective and promising target for the development of new antibacterial agents. Since deformylase inhibitors have yet to be used clinically as antibacterial drugs, compounds targeting this enzyme should avoid cross-resistance with currently used antibacterial agents. The PDF enzyme is a ferrous ion-containing metallohydrolase, but a nickel-containing surrogate is routinely used in the laboratory for testing inhibitors due to its better stability. Enzymes from several bacterial species have been cloned and both their three-dimensional structures and co-crystal structures with bound inhibitor have been determined. As a metallo enzyme, PDF lends itself to the well-precedented mechanism-based rational drug design approach. Using structural and mechanistic information together with high throughput screening, several types of potent PDF inhibitors have been identified. PDF inhibitors identified to date share a common structural feature of a "chelator + peptidomimetic" scaffold. Although compounds with many different chelators inhibit the cell free enzyme, only compounds containing hydroxamic acid or N-formyl hydroxylamine exhibit appreciable antibacterial activity. Several lead inhibitors have demonstrated in vivo efficacy and an excellent safety profile. Two PDF inhibitors, VIC-104959 (LBM415) and BB-83698, have progressed to Phase I clinical trials. In this review, different PDF inhibitors are compared and their biological activities are discussed. Structure-activity relationships have been established and the implications of this work in the design of future PDF inhibitors are considered.

Potent inhibitory ligands of the GRB2 SH2 domain from recombinant peptide libraries.

We cloned and expressed the SH2 domain of human GRB2 as glutathione S-transferase and maltose binding protein fusion proteins. We screened three phagemid-based fd pVIII-protein phage display libraries against SH2 domain fusion proteins. Sequence analysis of the peptide extensions yielded a variety of related peptides. By examining the ability of the phage clones to bind other SH2 domains, we demonstrated that the phage were specific for the SH2 domain of GRB2. Based on the sequence motif identified in the "random" library screening experiment, we also built and screened a phage display library based on a Tyr-X-Asn motif (X5-Tyr-X-Asn-X8). To examine the affinity of the phage derived peptides for GRB2, we set up a radioligand competition binding assay based on immobilized GRB2 and radiolabelled autophosphorylated EGFR ICD as the radioligand. Results obtained with peptide competitors derived from the phage sequences demonstrated that nonphosphotyrosine-containing peptides identified with the phage display technology had an affinity for the receptor similar to tyrosine-phosphorylated peptides derived from the EGFR natural substrate. Interestingly, when the phage display peptides were then phosphorylated on tyrosine, their affinity for GRB2 increased dramatically. We also demonstrated the ability of the peptides to block the binding of the GRB2 SH2 domain to EGFR in a mammalian cell-based binding assay.

On the usefulness of somatosensory evoked responses for the evaluation of lower back pain.

Electrodiagnostic and concurrent computed tomographic (CT) scan data were reviewed from 30 patients with lower back pain and unilateral radicular symptoms. Electrodiagnostic examination included somatosensory evoked responses (SSEPs) of the L-4, L-5, and S-1 roots stimulating specific sensory nerves. In three patients with normal CT scans, electrophysiologic studies were unrevealing. In the remaining 27 patients, CT scans were consistent with root injury, as were 15 of 17 myelograms. In 21 of these 27 patients, SSEP abnormalities consistent with focal root dysfunction and the radiographic findings were present. Other electrodiagnostic abnormalities (ie, electromyographic F response or H reflex) were limited to the six patients with clinical signs. These data indicate that SSEPs are valuable for evaluating root injury in patients with lower back pain, particularly where focal sensorimotor or reflex signs are absent.

Rational design and combinatorial evaluation of enzyme inhibitor scaffolds: identification of novel inhibitors of matrix metalloproteinases.

The discovery of a novel series of heterocyclic matrix metalloproteinase (MMPs) inhibitors is described. Published crystal structures of peptidyl hydroxamates bound to MMPs were the basis for the rational design of diketopiperazine (DKP) inhibitors. Combinatorial libraries were prepared and evaluated for their ability to inhibit collagenase-1, stromelysin-1, and gelatinase-B substrate hydrolysis. Deconvolution of active pools resulted in the identification of potent inhibitors (IC50's < 100 nM) of collagenase-1 and gelatinase-B, with the most potent inhibitor exhibiting an IC50 of 30 nM against collagenase-1. A description of the combinatorial evaluation process, as well as initial SAR interpretation for this novel series, is provided.

Farnesyl diphosphate-based inhibitors of Ras farnesyl protein transferase.

The rational design, synthesis, and biological activity of farnesyl diphosphate (FPP)-based inhibitors of the enzyme Ras farnesyl protein transferase (FPT) is described. Compound 3, wherein a beta-carboxylic phosphonic acid type pyrophosphate (PP) surrogate is connected to the hydrophobic farnesyl group by an amide linker, was found to be a potent (I50(FPT) = 75 nM) and selective inhibitor of FPT, as evidenced by its inferior activity against squalene synthetase (I50(SS) = 516 microM) and mevalonate kinase (I50(MK) = > 200 microM). A systematic structure-activity relationship study involving modifications of the farnesyl group, the amide linker, and the PP surrogate of 3 was undertaken. Both the carboxylic and phosphonic acid groups of the beta-carboxylic phosphonic acid PP surrogate are essential for activity, since deletion of either group results in 50-2600-fold loss in activity (6-9, I50 = 4.6-220 microM). The farnesyl group also displays very stringent requirements and does not tolerate one carbon homologation (12, I50 = 17.7 microM), substitution by a dodecyl fragment (14, I50 = 9 microM), or introduction of an extra methyl group at the allylic position (18, I50 = 55 microM). Modifications around the amide linker group of 3 were more forgiving, as evidenced by the activity of N-methyl analog (21, I50 = 0.53 microM), the one carbon atom shorter farnesoic acid-derived retroamide analog (32, I50 = 250 nM), and the exact retroamide analog (49, I50 = 50 nM). FPP analogs such as 3, 32, and 49 are novel, potent, selective, small-sized, nonpeptidic inhibitors of FPT that may find utility as antitumor agents.

Hydroxamic acid-based bisubstrate analog inhibitors of Ras farnesyl protein transferase.

The rational design, synthesis, and activity of novel, hydroxamic acid-based, collective bisubstrate analog inhibitors of farnesyl protein transferase (FPT) is described. This class of compounds differ structurally from the conventional FPT inhibitors by being non-sulfhydryl and by being bisubstrate based rather than peptide or FPP derived inhibitors. Whereas replacement of the sulfhydryl group of tetrapeptide CVLS (I50 = 1 microM) by an N-methylhydroxamic acid had a deleterious effect (10, I50 > 360 microM), moderate inhibition was realized with 16 (I50 = 42.5 microM), a bisubstrate analog involving anchorage of farnesyl and tripeptide groups by a hydroxamic acid-embedded linker. Starting from 16, a 1 order of magnitude improvement in in vitro potency was obtained by optimization of the linker (20, I50 = 4.35 microM). An additional 13-fold enhancement was achieved by substituting the tripeptide moiety VLS in 20 by VVM (23, I50 = 0.33 microM). The dependence of these inhibitors on their peptide and farnesyl subunits is suggestive of their bisubstrate nature. Compound 23 (I50 = 0.33 microM) is 2 orders of magnitude better in activity compared to the initial lead 16 [I50 = 42.5 microM) and is effective in blocking prenylation of protein in whole cells including p21ras.

Activated ketone based inhibitors of human renin.

Application of the concept of activated ketones to the design of novel and potent transition-state analog inhibitors of the aspartyl protease renin is described. Three different classes of peptidic activated ketones were synthesized: 1,1,1-trifluoromethyl ketones, alpha-keto esters, and alpha-diketones. The corresponding alcohols were also evaluated as renin inhibitors in each series. While the trifluoromethyl alcohol 12 (I50 = 4000 nM) was equipotent to the simple methyl alcohol 7 (I50 = 3200 nM), the structurally similar alpha-hydroxy esters (32 and 30, I50's = 5.3 and 4.7 nM, respectively) and alpha-hydroxy ketones (41 and 42, I50 = 23 and 15 nM, respectively) were 150-300-fold more active. The hydrating capability of the activated ketone functionality was important for intrinsic potency in the case of trifluoromethyl ketones, as illustrated by the significantly better activity of trifluoromethyl ketone 13 (I50 = 250 nM) compared to its alcohol analog 12 (I50 = 4000 nM). It was however unimportant for the alpha-keto ester (20 and 31, I50 = 15 and 4.1 nM, respectively) and alpha-diketone (43 and 44, I50 = 52 and 28 nM, respectively) based inhibitors, since their activity was essentially similar to that of the corresponding alcohols. These results collectively suggest that, whereas the trifluoromethyl ketones derive their renin inhibitory potency primarily from their ability to become hydrated, this is not a critical feature for the activity of alpha-dicarbonyl-based inhibitors. The alpha-keto ester and alpha-diketone based renin inhibitors benefit predominantly from the hydrophobic and/or H-bonding type binding interactions of the neighboring ester or acyl group itself, rather than the ability of this group to deactivate the adjacent ketone group and thereby make it susceptible to hydration.

alpha-Hydroxy phosphinyl-based inhibitors of human renin.

The design and application of alpha-hydroxy phosphonates, a new class of transition state analogs, toward the discovery of novel and potent inhibitors of the aspartyl protease renin is described. Tripeptidic alpha-hydroxy diethyl phosphonate 3, the first example in this series, was found to be a good inhibitor of human renin (IC50 = 29 nM), and preliminary studies led to the choice of alpha-hydroxy dimethyl phosphonate 15 (IC50 = 16 nM) as a base-line compound for further structure-activity relationship study. Corresponding phosphinate (28-30) and phosphine oxide (23 and 24) analogs of 15 were prepared to assess the steric and electronic requirements around the phosphorus center. Evaluation of these analogs suggested that the presence of at least one alkoxy group on phosphorus was a critical requirement for good activity. Inhibitors with leucine at P2 possessed better in vitro activity than the corresponding P2 histidine analogs (15, IC50 = 16 nM vs 37, IC50 = 220 nM; 33, IC50 = 8.5 nM vs 40, IC50 = 41 nM). Compound 34 (IC50 = 31 nM), the P3 aminocaproic analog of 15, showed complete and long-lasting inhibition of plasma renin activity while eliciting a 10-15 mmHg drop in mean arterial pressure when administered intravenously at 1 mumol/kg in conscious, sodium-depleted, cynomolgus monkeys. In summary, the alpha-hydroxy phosphonates represent a promising and structurally novel class of transition state analog inhibitors of human renin.

Phosphinyl acid-based bisubstrate analog inhibitors of Ras farnesyl protein transferase.

The rational design, synthesis, and biological activity of phosphonyl- and phosphinyl-linked bisubstrate analog inhibitors of the enzyme Ras farnesyl protein transferase (FPT) are described. The design strategy for these bisubstrate inhibitors involved connection of the critical binding components of the two substrates of FPT (ras protein and farnesyl pyrophosphate, FPP) through a phosphonyl- or phosphinyl-bearing linker. Compound 14, the first example in this series, was found to be a potent FPT inhibitor (I50 = 60 nM). A further 15-fold enhancement in activity was observed upon replacement of the VLS tripeptide sequence in 14 with VVM (15, I50 = 6 nM). The phosphinic acid analog 16 (I50 = 6 nM) was equiactive to phosphonic acid 15. Compounds 14-16 afforded 1000-fold selectivity for FPT against the closely related enzyme geranylgeranyl protein transferase type I, GGT-I [14, I50(GGT-I) = 59 microM; 15 I50(GGT-I) = 10 microM; 16 I50(GGT-I) = 21 microM]. Methyl and POM ester prodrugs 17-19 were prepared and evaluated in whole cell assays and appear to block ras-induced cell transformation, as well as colony formation in soft agar. A distinctive feature of this novel class of potent and selective bisubstrate FPT inhibitors is that they are non-sulfhydryl in nature.

Development of highly potent inhibitors of Ras farnesyltransferase possessing cellular and in vivo activity.

Analogs of CVFM (a known nonsubstrate farnesyltransferase (FT) inhibitor derived from a CA1A2X sequence where C is cysteine, A is an aliphatic residue, and X is any residue) were prepared where phenylalanine was replaced by (Z)-dehydrophenylalanine, 2-aminoindan-2-carboxylate, 1,2,3,4-tetrahydroisoquinoline-3-carboxylate (Tic), and indoline-2-carboxylate. The greatest improvement in FT inhibitory potency was observed for the Tic derivative (IC50 = 1 nM); however, this compound was ineffective in blocking oncogenic Ras-induced transformation of NIH-3T3 fibroblast cells. A compound was prepared in which both the Cys-Val methyleneamine isostere and the Tic replacement were incorporated. This derivative inhibited FT with an IC50 of 0.6 nM and inhibited anchorage-independent growth of stably transformed NIH-3T3 fibroblast cells by 50% at 5 microM. Replacing the A1 side chain of this derivative with a tert-butyl group and replacing the X position with glutamine led to a derivative with an IC50 of 2.8 nM and an EC50 of 0.19 microM, a 26-fold improvement over (S*,R*)-N-[[2-[N-(2-amino-3-mercaptopropyl)-L-valyl]-1,2,3,4- tetrahydro-3-isoquinolinyl]carbonyl]-L-methionine. This derivative, (S*,R*)-N-[[2-[N-(2-amino-3-mercaptopropyl)-L-tert-leucyl]-1,2,3,4 - tetrahydro-3-isoquinolinyl]-carbonyl]-L-glutamine, was evaluated in vivo along with (S*,R*)-N-[[2-[N-(2-amino-3- mercaptopropyl)-L-tert-leucyl]-1,2,3,4-tetrahydro-3- isoquinolinyl]carbonyl]-L-methionine methyl ester for antitumor activity in an athymic mouse model implanted ip with H-ras-transformed rat-1 tumor cells. When administered by injection twice a day at 45 mg/kg for 11 consecutive days, both compounds showed prolonged survival time (T/C = 142-145%), thus demonstrating efficacy against ras oncogene-containing tumors in vivo.

Sonography of the kidneys in hemolytic uremic syndrome.

The sonographic appearance of kidneys in patients presenting with acute renal failure due to hemolytic-uremic syndrome (HUS) was evaluated and compared with that in an age-matched control series. In nine patients with HUS, the renal cortex was typically hyperechogenic and the renal pyramids appeared sonolucent. The renal size was normal or enlarged compared with 35 normal controls. While not specific, the sonographic patterns described in this study support the diagnosis of HUS in the appropriate clinical setting.

Symptomatic spinal stenosis associated with ankylosing spondylitis.

Patients with ankylosing spondylitis frequently experience back pain and they have a well-known propensity for spinal fractures, but they rarely manifest motor and sensory nerve root impairment. We recently encountered a patient with ankylosing spondylitis who complained of classical spinal claudication with urinary sphincter dysfunction. Computed axial tomography revealed marked lumbosacral lateral recess and foraminal spinal stenosis that was not evident on the myelogram; at operation the stenosis appeared to be the result of extensive posterior soft tissue ossification. This heretofore unrecognized yet potentially treatable complication of ankylosing spondylitis is discussed.

Anterior cruciate ligament injuries in young athletes. Recommendations for treatment and rehabilitation.

Complete midsubstance tears of the anterior cruciate ligament (ACL) in skeletally-immature adolescents are being diagnosed and reported with increasing frequency. Conservative treatment of such ACL tears in junior high schools, subsequent meniscal tears, and very early osteoarthritis. Results of primary repair of the torn ACL and extra-articular reconstructive procedures have been disappointing. Intra-articular ACL reconstruction in young athletes approaching skeletal maturity using the autogenous patellar tendon graft gives excellent knee stability, and decreases the risk of meniscal tears. Athletes are able to return to competitive sports at their preinjury level. Here, the existing literature on the subject of midsubstance ACL tears in young athletes is reviewed, and guidelines for the management of ACL-deficient knee in this population are provided.

The natural history of acute, isolated, nonoperatively treated posterior cruciate ligament injuries. A prospective study.

We sought to determine prospectively the natural history of acute, isolated, nonoperatively treated posterior cruciate ligament injuries in athletically active patients. The study population consisted of 133 patients (average age, 25.2 years at time of injury). All patients completed a subjective questionnaire each year for an average of 5.4 years (range, 2.3 to 11.4). Sixty-eight of the 133 patients returned to the clinic for long-term follow-up evaluation. Objectively, physical examination revealed no change in laxity from initial injury to follow-up. No correlation was found between radiographic joint space narrowing and grade of laxity. The mean modified Noyes knee score was 84.2 points, the mean Lysholm score was 83.4, and the mean Tegner activity score was 5.7. Patients with greater laxity did not have worse subjective scores. No correlation was found between subjective knee scores and time from injury. Regardless of the amount of laxity, half of the patients returned to the same sport at the same or higher level, one-third returned to the same sport at a lower level, and one-sixth did not return to the same sport. Results of this study suggest that athletically active patients with acute isolated posterior cruciate ligament tears treated nonoperatively achieved a level of objective and subjective knee function that was independent of the grade of laxity.

Classification and management of arthrofibrosis of the knee after anterior cruciate ligament reconstruction.

We report 72 patients with disabling knee arthrofibrosis who were treated at our clinic. All patients had painful restriction of extension or limitation of both extension and flexion that had persisted despite physical therapy. The level of arthrofibrosis was categorized into one of four types: Type 1 (25 patients), < 10 degree extension loss and normal flexion; Type 2 (16 patients), > 10 degree extension loss and normal flexion; Type 3 (15 patients), > 10 degree extension loss and > 25 degree flexion loss with a tight patella; and Type 4 (16 patients), > 10 degree extension loss, 30 degrees or more flexion loss, and patella infera with marked patellar tightness. All patients were treated with outpatient arthroscopic surgery. Anterior scar resection down to the proximal tibia was required for all patients with Types 2, 3, and 4 arthrofibrosis. Notchplasty was performed when necessary. Medial and lateral capsular releases and knee manipulation were required for patients with Type 3 or 4 arthrofibrosis. Postoperatively, all patients with Types 2, 3, and 4 arthrofibrosis were treated with outpatient serial extension casting. At the time of latest followup (28 to 115 months), the mean improvement of range of motion was as follows: Type 1, 7 degrees of extension; Type 2, 14 degrees of extension; Type 3, 13 degrees of extension and 28 degrees of flexion; and Type 4, 18 degrees of extension and 27 degrees of flexion. Improvement was also found for the mean stiffness, self-evaluation, functional activity, and Noyes knee scores in all groups.

The natural history and treatment of rupture of the anterior cruciate ligament in children and adolescents. A prospective review.

A total of 60 children and adolescents with rupture of the anterior cruciate ligament (ACL) was seen between 1980 and 1990. Observation of the 23 patients who were treated conservatively revealed that the natural history of the injury resulted in severe instability and poor function of the knee. Associated meniscal tears were present in 15 knees. Three osteochondral fractures occurred and osteoarthritic changes developed in ten knees. In 1990 therefore we introduced reconstruction of the ACL with a four-strand hamstring graft using an anatomical placement with transphyseal tunnels and anchorage well away from the growth plate. Over a period of nine years, 47 knees underwent reconstruction. The mean follow-up was 49 months (12 to 96). No child suffered physeal damage or leg-length discrepancy. The results were satisfactory in 77% and there was little difference between patients treated before the adolescent growth spurt and those treated during or after this time. These results, however, were not as good as those seen in adults during the same period.

Congenital discoid lateral meniscus in children. A follow-up study and evolution of management.

Fifty-two children with 62 discoid lateral menisci were reviewed at an average follow-up of 5.5 years. Their average age at operation was 10.5 years and the mean delay in diagnosis was 24 months. Most of the children had vague and intermittent symptoms and the classical clunk was demonstrable in only 39% of the knees. An associated osteochondritis dissecans of the lateral femoral condyle was seen in seven knees. Forty-eight knees with symptomatic torn discoid menisci underwent open total lateral meniscectomy, six had arthroscopic partial meniscectomy and eight knees with intact discoid menisci, were left alone. Based on Ikeuchi's grading (Ikeuchi 1982), 37% of the knees had an excellent result, 47% had a good result and 16% had a fair result: none was poor. Arthroscopic partial meniscectomy is recommended only when the posterior attachment of the discoid meniscus is stable. A total meniscectomy is indicated for the Wrisberg-ligament type of discoid meniscus with posterior instability.

Giant serpentine intracranial aneurysm.

Giant serpentine aneurysms are considered a distinct subgroup of giant aneurysms because of their characteristic angiographic appearance and clinical behavior. A case of this unusual vascular abnormality showing progressive enlargement documented by computed tomography and cerebral angiography is presented, along with a review of the literature. Etiology, pertinent radiological findings, and a probable mechanism of serpentine channel formation are discussed.

Perioperative considerations in patients with metastatic bone disease.

Preoperative assessment of patients with metastatic bone disease includes a history and physical examination, laboratory evaluation, and standard radiographs. Perioperative diagnostics include technetium bone scan, CT scans, MR imaging, positron emission tomography, and biopsy. The role of preoperative tumor embolization and vena cava filter placement is discussed in this article. Guidelines for pain control are provided. Surgical planning and instrument considerations for long bone lesions, periarticular lesions, and pelvis and acetabular lesions are addressed. The importance of rehabilitation for patients with metastatic bone disease is emphasized.