Design of Novel Series of Antimalarial PMX Inhibitors with Increased Half-Life via Molecular Property Optimization

Plasmepsin X (PMX) has been identified as a multistage antimalarial target. PMX is a malarial aspartyl protease essential for merozoite egress from infected red blood cells and invasion of the host erythrocytes. Previously, we reported the identification of PMX inhibitors by structure-based optimization of a cyclic guanidine core. Preclinical assessment of UCB7362, which displayed both in vitro and in vivo antimalarial activity, revealed a suboptimal dose paradigm (once daily dosing of 50 mg for 7 days for treatment of uncomplicated malaria) relative to current standard of care (three-dose regime). We report here the efforts toward extending the half-life (t1/2) by reducing metabolic clearance and increasing volume of distribution (Vss). Our efforts culminated in the identification of a biaryl series, with an expected longer t1/2 in human than UCB7362 while maintaining a similar in vitro off-target hit rate.

Discovery and Characterization of Potent, Efficacious, Orally Available Antimalarial Plasmepsin X Inhibitors and Preclinical Safety Assessment of

Plasmepsin X (PMX) is an essential aspartyl protease controlling malaria parasite egress and invasion of erythrocytes, development of functional liver merozoites (prophylactic activity), and blocking transmission to mosquitoes, making it a potential multistage drug target. We report the optimization of an aspartyl protease binding scaffold and the discovery of potent, orally active PMX inhibitors with in vivo antimalarial efficacy. Incorporation of safety evaluation early in the characterization of PMX inhibitors precluded compounds with a long human half-life (t_1/2) to be developed. Optimization focused on improving the off-target safety profile led to the identification of UCB7362 that had an improved in vitro and in vivo safety profile but a shorter predicted human t_1/2. UCB7362 is estimated to achieve 9 log 10 unit reduction in asexual blood-stage parasites with once-daily dosing of 50 mg for 7 days. This work demonstrates the potential to deliver PMX inhibitors with in vivo efficacy to treat malaria.

Fused thiophene derivatives as MEK inhibitors

A number of novel fused thiophene derivatives have been prepared and identified as potent inhibitors of MEK. The SAR data of selected examples and the in vivo profiling of compound 13 h demonstrates the functional activity of this class of compounds in HT-29 PK/PD models.

Hyaluronan (hyaluronic acid) in human saliva

Hyaluronan (hyaluronic acid) is a glycosaminoglycan that functions as a constituent of ground substance, a mediator of cell proliferation and would healing, and that plays a prominent part in tumorigenesis as well as in embryogenesis. Its presence and possible role in saliva has been subjected to little study. Unstimulated and stimulated pure parotid and mixed saliva was obtained from 10 volunteers. The protein content of the samples was assayed and the hyaluronan concentration was evaluated by means of an enzyme immunosorbent-like assay using a hyaluronan-binding peptide. Stimulated whole saliva had the highest protein content (mean 1.26 mg/ml) followed by unstimulated parotid saliva (1.15 mg/ml), stimulated parotid saliva (0.95 mg/ml) and unstimulated whole saliva (0.93 mg/ml). Absolute hyaluronan concentrations were highest in unstimulated whole saliva (mean 459.2 ng (nanograms)/ml), and lowest in stimulated parotid saliva (82.7 ng/ml). When hyaluronan concentrations are expressed as ng/mg of protein, the highest are in the unstimulated whole saliva (mean 477.5 ng/mg protein) followed by stimulated parotid saliva (229.7 ng/mg), unstimulated parotid saliva (179.6 ng/mg) and stimulated whole saliva (159.9 ng/mg). There are wide variations in the levels of hyaluronan in human saliva depending on the type of saliva and the conditions at the time of collection. Regulation of hyaluronan metabolism represents an intricate balance between production and degradation, and it is unclear whether elevated concentrations of hyaluronan in response to tissue proliferation, regeneration or repair. The hyaluronan may contribute to the healing properties of saliva, assisting in protecting the oral mucosa and adding to the lubricating properties of saliva.

New endourologic technique for catheter placement after TURP, prostatectomy, and difficult urethroscopy

Inserting a Foley catheter into a traumatized urethra with false channels or a post-transurethral resection of prostate (TURP) undermined bladder neck can be very difficult if not impossible at times. Likewise, replacing a Foley catheter that has fallen out in the early postoperative period after a radical prostatectomy can be difficult and can cause significant injury to the fresh anastomosis. We describe a technique using a Peel-Away sheath that fits over a cystoscope or a resectoscope, and facilitates accurate insertion of a Foley catheter without trauma to the urethra.

Surgical management of subfoveal choroidal neovascularization

BACKGROUND

Subfoveal choroidal neovascularization (CNV) usually is associated with a poor visual prognosis. Laser photocoagulation of certain subfoveal membranes secondary to age-related macular degeneration (ARMD) appears preferable to observation based on recent Macular Photocoagulation Study (MPS) findings but is associated with decreased vision. The authors explored the use of vitreoretinal surgical techniques as an alternative method of eradicating subfoveal CNV.

METHODS

After vitrectomy, a small retinotomy technique was used to extract or disconnect from the choroidal circulation subfoveal CNV in 58 eyes. There were 33 eyes with ARMD, 20 eyes with presumed ocular histoplasmosis, and 5 eyes with miscellaneous etiologies. Five eyes also received subfoveal RPE patches.

RESULTS

With limited follow-up, significant improvement in vision (defined as 2 Snellen lines) was achieved in 7 of 22 eyes with ARMD CNV removal (1 eye 20/20), 0 of 4 eyes with ARMD CNV removal and RPE patches, and 1 of 7 eyes with ARMD CNV disconnection. Significant improvement was achieved in 6 of 16 eyes with presumed ocular histoplasmosis removal and 0 of 4 eyes with presumed ocular histoplasmosis CNV disconnection. In 5 eyes with miscellaneous CNV, 2 improved (20/20 and 20/40). CNV recurred in 29%.

CONCLUSIONS

Some patients with subfoveal CNV appear to benefit from surgical removal. Only rarely do eyes with ARMD improve. Longer-term follow-up and refined case selection are required before this approach can be widely recommended.

Controlled trial of infusion cavernosometry in impotent and potent men

Infusion cavernosometry often is performed to diagnose venous leak impotence. However, normal values have seldom been established in proved potent men. We performed a prospective study of infusion cavernosometry on nocturnal penile tumescence confirmed potent male volunteers and impotent men. Of 20 potent male controls 19 had resistance values of greater than 5 (mm. Hg.minute)/ml. Of 38 impotent men 20 (53%) had resistance values of less than 5 (mm.Hg. minute)/ml. There was considerable overlap between resistance values and infusion rates in potent and impotent men. Impotent men with resistances of greater than 5 (mm.Hg.minute)/ml. more often had normal nocturnal penile tumescence results than men with lower resistance values. Venous leakage is a significant cause of impotence.

Repair of a traumatically amputated penis with return of erectile function

Repair of the amputated penis may be successful using macroscopic and microscopic surgical realignments. However, to date, no one has reported return of erectile function documented by nocturnal penile tumescence. We report a case of traumatically amputated penis with microscopic repair and return of erectile function documented by nocturnal penile tumescence. In addition, the current literature regarding microscopic versus nonmicroscopic repair is reviewed.

A comparison of penile brachial index and angiography: evaluation of corpora cavernosa arterial inflow

We studied 32 impotent patients with angiography. The penile branchial index was calculated from the maximal penile arterial pressure measured from any penile artery. In 15 of the 32 patients an attempt was made to isolate the cavernous artery pressure (cavernous artery penile brachial index). There was a poor correlation between angiography and penile branchial index (r equals 0.314) and between angiography and cavernous penile brachial index (r equals 0.637). We also evaluated 15 normal individuals and a wide range of penile brachial index values was found (0.7 to 1.0). Penile brachial index values from normal patients overlapped with those from impotent patients. Penile brachial index values from impotent patients with normal and abnormal arteries (as determined by angiography) overlapped. The fact that penile brachial index measurements are performed in the flaccid state and without direct visualization of the cavernous arteries accounts for some of the variability of the penile brachial index test.

Pneumatic retinopexy. Surgical results

We reviewed 55 consecutive cases of rhegmatogenous retinal detachment treated with pneumatic retinopexy. Eyes with inferior retinal breaks from the 4- to 8-o'clock positions or macular holes with retinal detachment were excluded. Forty-five eyes (82%) were reattached with one operation. Although ten operations failed, nine retinas were subsequently reattached surgically, a 98% overall reattachment rate. Thirty-three (92%) of 36 phakic eyes, eight (66%) of 12 pseudophakic eyes, and four (57%) of seven aphakic retinas were reattached with one operation. In macula-off cases, phakic patients tended to have greater improvement in visual acuity. New breaks occurred in six eyes (11%), five (83%) of which were pseudophakic or aphakic. The safety, efficacy, and indications for pneumatic retinopexy remain to be established by a randomized, controlled, prospective study.

Risk factors for urethral injuries in men with traumatic pelvic fractures

Urethral injuries are commonly associated with pelvic fractures. The prompt recognition and appropriate management of these injuries may significantly impact subsequent morbidity, yet few studies have addressed the identification of the risk factors for urethral injury in men with pelvic fractures. We reviewed retrospectively the records of 405 men with pelvic fractures seen at our medical center, including 21 (5 per cent) with urethral injuries. Of the 21 men 14 (67 per cent) had fractures involving a pubic ramus and a sacroiliac joint, and 12 (57 per cent) had no physical signs (blood at the urethral meatus, perineal hematoma or a high-riding prostate) that would suggest a urethral injury. The likelihood for the presence of physical signs is directly related to the interval since injury. We believe that men with the combination of rami fractures and sacroiliac disruption should undergo retrograde urethrograms before urethral instrumentation, and that physical signs are unreliable indications for urethral injuries, especially soon after the injury.

Vibrio vulnificus infection after raw oyster ingestion in a patient with liver disease and acquired immune deficiency syndrome-related complex

Sepsis, peritonitis, and gastroenteritis developed in a 45-yr-old homosexual man 1 day after ingestion of raw oysters. The patient had chronic active hepatitis and cirrhosis with hepatitis B virus and delta-infection. He also had persistent generalized lymphadenopathy associated with HTLV-III antibody positivity. Vibrio vulnificus was isolated from the patient's blood and peritoneal fluid as well as from the same batch of oysters at the restaurant where the patient had visited. To our knowledge, this is the first report relating direct microbiologic and clinical evidence that the infection is acquired through the gastrointestinal tract by consuming raw seafood containing the pathogen. This is also the first reported case of peritonitis associated with sepsis and gastroenteritis from this organism. Patients with liver disease and other immunocompromised states should be warned about such life-threatening infections and complications associated with the consumption of raw oysters or other undercooked seafoods.

Immunoelectron microscopic analysis of elongation of type 1 fimbriae in Escherichia coli

Using 10- and 20-nm-diameter gold particles conjugated to an antifimbrial monoclonal antibody, we analyzed the location of assembly of newly formed subunits on growing type 1 fimbriae of Escherichia coli. Fimbriae were removed from an E. coli K-12-derived strain, CSH50, by blending. Blended cells were allowed to regenerate their fimbriae in growth medium for approximately 25 min, after which they were labeled with a 20-nm-gold-monoclonal antibody probe. Continued outgrowth of these labeled fimbriae was allowed for additional time intervals, after which they were labeled with a 10-nm-gold-monoclonal antibody probe. The resulting fimbriae, double labeled with 10- and 20-nm-diameter gold particles, were examined in an electron microscope. The pattern of labeling on individual fimbrial organelles indicated morphologically that newly synthesized subunits are added to a growing organelle at its base.