Persistence of the efficacy of zoster vaccine in the shingles prevention study and the short-term persistence substudy.

BACKGROUND: The Shingles Prevention Study (SPS; Department of Veterans Affairs Cooperative Study 403) demonstrated that zoster vaccine was efficacious through 4 years after vaccination. The Short-Term Persistence Substudy (STPS) was initiated after the SPS to further assess the persistence of vaccine efficacy. METHODS: The STPS re-enrolled 7320 vaccine and 6950 placebo recipients from the 38 546-subject SPS population. Methods of surveillance, case determination, and follow-up were analogous to those in the SPS. Vaccine efficacy for herpes zoster (HZ) burden of illness, incidence of postherpetic neuralgia (PHN), and incidence of HZ were assessed for the STPS population, for the combined SPS and STPS populations, and for each year through year 7 after vaccination. RESULTS: In the STPS as compared to the SPS, vaccine efficacy for HZ burden of illness decreased from 61.1% to 50.1%, vaccine efficacy for the incidence of PHN decreased from 66.5% to 60.1%, and vaccine efficacy for the incidence of HZ decreased from 51.3% to 39.6%, although the differences were not statistically significant. Analysis of vaccine efficacy in each year after vaccination for all 3 outcomes showed a decrease in vaccine efficacy after year 1, with a further decline thereafter. Vaccine efficacy was statistically significant for the incidence of HZ and the HZ burden of illness through year 5. CONCLUSIONS: Vaccine efficacy for each study outcome was lower in the STPS than in the SPS. There is evidence of the persistence of vaccine efficacy through year 5 after vaccination but, vaccine efficacy is uncertain beyond that point.

A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults.

BACKGROUND: The incidence and severity of herpes zoster and postherpetic neuralgia increase with age in association with a progressive decline in cell-mediated immunity to varicella-zoster virus (VZV). We tested the hypothesis that vaccination against VZV would decrease the incidence, severity, or both of herpes zoster and postherpetic neuralgia among older adults. METHODS: We enrolled 38,546 adults 60 years of age or older in a randomized, double-blind, placebo-controlled trial of an investigational live attenuated Oka/Merck VZV vaccine ("zoster vaccine"). Herpes zoster was diagnosed according to clinical and laboratory criteria. The pain and discomfort associated with herpes zoster were measured repeatedly for six months. The primary end point was the burden of illness due to herpes zoster, a measure affected by the incidence, severity, and duration of the associated pain and discomfort. The secondary end point was the incidence of postherpetic neuralgia. RESULTS: More than 95 percent of the subjects continued in the study to its completion, with a median of 3.12 years of surveillance for herpes zoster. A total of 957 confirmed cases of herpes zoster (315 among vaccine recipients and 642 among placebo recipients) and 107 cases of postherpetic neuralgia (27 among vaccine recipients and 80 among placebo recipients) were included in the efficacy analysis. The use of the zoster vaccine reduced the burden of illness due to herpes zoster by 61.1 percent (P<0.001), reduced the incidence of postherpetic neuralgia by 66.5 percent (P<0.001), and reduced the incidence of herpes zoster by 51.3 percent (P<0.001). Reactions at the injection site were more frequent among vaccine recipients but were generally mild. CONCLUSIONS: The zoster vaccine markedly reduced morbidity from herpes zoster and postherpetic neuralgia among older adults.

The effects of deep diaphragmatic breathing and focused attention on dental anxiety in a private practice setting.

PURPOSE: High dental anxiety is pervasive and associated with treatment avoidance and poor oral health. Ideally, anxiety reduction techniques should be easy to use, low in cost, non-pharmacological, comfortable, and effective. This study compared the effectiveness of two self-taught anxiety reduction techniques--breathing and focused attention--with a control group. METHODS: Anxiety was assessed in 272 adult private dental practice patients with a modified dental anxiety scale-revised. Frequency of oral health care visits in the last 10 years to all dentists, including the current dentist, was collected. Immediately prior to the dental procedure, participants in the two experimental groups were given written instructions outlining the respective anxiety reduction technique they were to use. Efficacy of technique was assessed by subjective comparison to anxiety during previous oral health treatment. Participants also listed techniques that they believed to be effective for anxiety reduction. RESULTS: Twenty-six participants (9.56%) scored high in dental anxiety. High anxiety was associated with infrequent oral health care visits. Compared to the recall of anxiety experienced during prior treatment, there were no significant differences in anxiety between breathing, focusing, and control groups. But there was a trend toward decreased anxiety overall. Controls who reported infrequent visits and use of their own anxiety reduction technique showed significantly reduced anxiety. CONCLUSION: Dental patients employ numerous strategies for anxiety reduction. Anxiety reduction techniques not yet practiced may place unwanted expectations on patients. It is suggested that oral health care practitioners be aware of the patient's preferred technique for coping with anxiety and encourage them to use self-help techniques.

Succinic acids as potent inhibitors of plasmid-borne IMP-1 metallo-beta-lactamase.

IMP-1 metallo-beta-lactamase (class B) is a plasmid-borne zinc metalloenzyme that efficiently hydrolyzes beta-lactam antibiotics, including carbapenems, rendering them ineffective. Because IMP-1 has been found in several clinically important carbapenem-resistant pathogens, there is a need for inhibitors of this enzyme that could protect broad spectrum antibiotics such as imipenem from hydrolysis and thus extend their utility. We have identified a series of 2,3-(S,S)-disubstituted succinic acids that are potent inhibitors of IMP-1. Determination of high resolution crystal structures and molecular modeling of succinic acid inhibitor complexes with IMP-1 has allowed an understanding of the potency, stereochemistry, and structure-activity relationships of these inhibitors.

Inhibition of bacterial peptide deformylase by biaryl acid analogs.

Peptide deformylase is an essential eubacterial metalloenzyme involved in the maturation of proteins by cleaving the N-formyl group from N-blocked methionine polypeptides. Biaryl acid analogs containing tetrazole, acyl sulfonamide, or carboxylate pharmacophores were found to be potent inhibitors of recombinant Escherichia coli peptide deformylase. Two of these compounds, a biphenyl tetrazole, compound 1, and a biphenyl acyl sulfonamide, compound 4, were competitive inhibitors with K(i) values of 1.2 and 6.0 microM, respectively. By analogy to the binding of related compounds to other metalloenzymes such as Bacteroides fragilis metallo-beta-lactamase CcrA and human carbonic anhydrase, a mechanism of inhibition is proposed for these peptide deformylase inhibitors where the acidic moieties form direct ionic interactions with the active site metal cation.

Inhibition of IMP-1 metallo-beta-lactamase and sensitization of IMP-1-producing bacteria by thioester derivatives.

IMP-1 metallo-beta-lactamase is a transferable carbapenem-hydrolyzing enzyme found in some clinical isolates of Pseudomonas aeruginosa, Serratia marcescens and Klebsiella pneumoniae. Bacteria that express IMP-1 show significantly reduced sensitivity to carbapenems and other beta-lactam antibiotics. A series of thioester derivatives has been shown to competitively inhibit purified IMP-1. As substrates for IMP-1, the thioesters yielded thiol hydrolysis products which themselves were reversible competitive inhibitors. The thioesters also increased sensitivity to the carbapenem L-742,728 in an IMP-1-producing laboratory stain of Escherichia coli, but will need further modification to improve their activity in less permeable organisms such as Pseudomonas and Serratia. Nonetheless, the thioester IMP-1 inhibitors offer an encouraging start to overcoming metallo-beta-lactamase-mediated resistance in bacteria.

Structure-activity relationships of biphenyl tetrazoles as metallo-beta-lactamase inhibitors.

Resistance to carbapenem antibiotics in gram-negative bacteria is due, in part, to expression of a wide spectrum metallo-beta-lactamase, which renders the drug inactive. Biphenyl tetrazoles containing 3-n-butyl-1-phenylpyrazole-5-carboxylates or the corresponding 5-ethyl esters were found to inhibit metallo-beta-lactamases as well as renal dehydropeptidase I to a lesser extent.

Synthesis and SAR of thioester and thiol inhibitors of IMP-1 metallo-beta-lactamase.

Potent thioester and thiol inhibitors of IMP-1 metallo-beta-lactamase have been synthesized employing a solid-phase Mitsunobu reaction as the key step.

Reduced immunotoxicity and preservation of antibacterial activity in a releasable side-chain carbapenem antibiotic.

A carbapenem antibiotic, L-786,392, was designed so that the side chain that provides high-affinity binding to the penicillin-binding proteins responsible for bacterial resistance was also the structural basis for ameliorating immunopathology. Expulsion of the side chain upon opening of the beta-lactam ring retained antibacterial activity while safely expelling the immunodominant epitope. L-786,392 was well tolerated in animal safety studies and had significant in vitro and in vivo activities against methicillin- and vancomycin-resistant Staphylococci and vancomycin-resistant Enterococci.

Recognizing and treating syphilis in pregnancy.

The number of primary and secondary syphilis cases in young women rose dramatically in the late 1980s and early 1990s, due to illicit drug use and the exchange of drugs for sex. Of infants born to mothers with primary or secondary syphilis, up to 50% will be premature, stillborn, or die in the neonatal period; further, most of these children are born with congenital disease that may not be apparent for years. While appropriate treatment of the pregnant female can prevent congenital syphilis, the major deterrent has been the inability to effectively identify these women and get them to undergo treatment. In determining a penicillin regimen, the clinician must consider the stage of maternal infection, the length of fetal exposure, and physiologic changes in pregnancy that can affect the pharmacokinetics of antibiotics. Treatment decisions may be further complicated in patients who are allergic to penicillin or infected with HIV. The pathogenesis of congenital syphilis is not completely understood, but placental invasion is the presumed major route. All women should be screened for syphilis with a nontreponemal test (eg, rapid plasma reagin [RPR] or venereal disease research laboratory [VDRL] test) in the first trimester. Those at high risk should be retested at 28 weeks and near delivery. Even with appropriate treatment of syphilis during pregnancy, fetal infection may still occur in up to 14% of cases. Treating syphilis during pregnancy can be difficult due to physiologic changes that can alter drug levels and the risk that drugs will induce uterine contractions or compromise the health of the fetus. While there are added risks and potential complications, treatment regimens parallel those in nonpregnant women.

Unanticipated inhibition of the metallo-beta-lactamase from Bacteroides fragilis by 4-morpholineethanesulfonic acid (MES): a crystallographic study at 1.85-A resolution.

As part of a structure-aided effort to design clinically useful inhibitors of metallo-beta-lactamases, the X-ray crystal structure of a complex between the metallo-beta-lactamase from Bacteroides fragilis and 4-morpholinoethanesulfonic acid (MES) has been determined and a model for the structure has been refined to a crystallographic R-factor of 0.151 for data between 10.0- and 1.85-A resolution. Although the binding of MES was an adventitious result of the use of MES as a buffer in the crystallization mixture, MES was subsequently shown to be a competitive inhibitor of the enzyme, with a Ki of 23 +/- 5 mM. MES binds in the same fashion to both of the molecules in the crystallographic asymmetric unit; both direct and solvent-mediated hydrogen bonds to the protein and to the binuclear zinc cluster are observed, involving the oxygens of the sulfonic acid group and the nitrogen of the morpholino ring. In addition, there are hydrophobic interactions between the morpholino ring and residues in the flexible beta-strand of the enzyme between residues 26 and 36. Comparison of this structure with the previously reported unliganded structures of the same enzyme [Concha, N. O., Rasmussen, B. A., Bush, K., and Herzberg, O. (1996) Structure 4, 823-836; Carfi, A., Duée, E., Paul-Soto, R., Galleni, M., Frère, J. -M., and Dideberg, O. (1998) Acta Crystallogr. D54, 47-57] reveals that although the overall conservation of structure in the three different crystal lattices is very high, binding of MES is correlated with a significant change in the conformation of this beta-strand. The flexibility of this beta-strand will be an important consideration in the design of inhibitors of the metallo-beta-lactamases.

Antibiotic sensitization using biphenyl tetrazoles as potent inhibitors of Bacteroides fragilis metallo-beta-lactamase.

BACKGROUND: High level resistance to carbapenem antibiotics in gram negative bacteria such as Bacteroides fragilis is caused, in part, by expression of a wide-spectrum metallo-beta-lactamase that hydrolyzes the drug to an inactive form. Co-administration of metallo-beta-lactamase inhibitors to resistant bacteria is expected to restore the antibacterial activity of carbapenems. RESULTS: Biphenyl tetrazoles (BPTs) are a structural class of potent competitive inhibitors of metallo-beta-lactamase identified through screening and predicted using molecular modeling of the enzyme structure. The X-ray crystal structure of the enzyme bound to the BPT L-159,061 shows that the tetrazole moiety of the inhibitor interacts directly with one of the two zinc atoms in the active site, replacing a metal-bound water molecule. Inhibition of metallo-beta-lactamase by BPTs in vitro correlates well with antibiotic sensitization of resistant B. fragilis. CONCLUSIONS: BPT inhibitors can sensitize a resistant B. fragilis clinical isolate expressing metallo-beta-lactamase to the antibiotics imipenem or penicillin G but not to rifampicin.

Soluble penicillin-binding protein 2a: beta-lactam binding and inhibition by non-beta-lactams using a 96-well format.

High level methicillin resistance in Staphylococcus aureus is dependent upon the acquisition of the mecA gene encoding penicillin-binding protein 2a (PBP2a). PBP2a is a member of a family of peptidoglycan biosynthetic enzymes involved in assembly of the cell wall in bacteria and is poorly inactivated by beta-lactam antibiotics. We describe a 96-well-filter binding assay using recombinant, soluble PBP2a which allows for kinetic measurement of penicillin binding. The deacylation rate constant for the PBP2a-penicillin G covalent complex was found to be 5.7 +/- 1.0 x 10(-5) s-1 at 30 degrees C (half-life of approximately 200 min). For the PBP2a acylation reaction, the value of K(m) (penicillin G) = 0.5 +/- 0.1 mM and kcat = 1 x 10(-3) s-1, which yields a second-order rate constant (kcat/K(m)) for inactivation of 2.0 M-1 s-1. Using this assay, several non-beta-lactam inhibitors including Cibacron blue have been found which exhibit IC50 values between 10 and 30 microM. The binding affinities of several carbapenems and beta-lactams correlated well between the filter binding assay described in this report and an electrophoretic assay for PBP2a using membranes prepared form methicillin-resistant S. aureus.

Infection versus colonization in the critical care unit.

Serious infections in the critical care unit are commonplace. However, distinguishing true infection from mere colonization is a difficult and often uncertain process that has been shown to result in both over- and under-treatment of patients. Antimicrobial agents used in the CCU setting are expensive and not without toxicities. This article discusses methods to differentiate colonization from infection.

STD interactive case challenge--diagnosing and treating chronic vulvar pain and erythema.

A 36-year-old Caucasian woman arrives in your office, her chief complaint being vulvar pain and discomfort of 2 years' duration. She says that the onset of vulvar erythema and pain was gradual, beginning with mild tingling discomfort and eventually developing into dyspareunia and pain whenever she attempted to insert tampons, wore tight-fitting pants, or went horseback riding. The patient denies having vaginal discharge, change in menstrual pattern, or dysuria. She says she complained of the problem to several previous clinicians, who recommended anti-infective treatment for candidal vulvovaginitis, bacterial vaginosis, and recurrent cystitis, yet the symptoms persisted. One physician suggested a psychiatric evaluation, but the patient refused. She switched soap, shampoo, and even underwear fabric in an unsuccessful effort to ameliorate the symptoms. Over the past 6 months she has become increasingly frustrated with this problem.

Examining the Complex Relationship of Human Papillomavirus to Cervical Dysplasia and Carcinoma.

Human papillomavirus (HPV) infection is quite common in women and is clearly the major risk factor for cervical intraepithelial neoplasia and invasive cervical cancer. HPV DNA has been detected in 80% to 90% of CIN 3 lesions and invasive cervical cancers. While the most common presentation is warts, or condylomata, many infections are detected only by Pap smear cytologic evidence. We still do not have a clear understanding of HPV latency, reactivation, subclinical infection without apparent disease, and the triggers or cofactors required for malignant transformation. More than 70 different strains of HPV have been identified, and specific subtypes have been associated with a greater risk of progression to dysplasia and cervical cancer. A better knowledge of the oncogenic mechanisms of HPV and improved diagnostic testing is critical to guide future therapeutic and preventive investigations. The Pap smear is used for initial screening; cytologic results suspicious for premalignancy or malignancy are subsequently evaluated by colposcopy and biopsy of suspicious lesions. Cervical cancer has been designated an AIDS-defining illness; in HIV-infected patients, the prevalence of HPV is 5 times that of the general population. Because the disease presents at a later stage in HIV-infected patients and is less responsive to treatment, close attention to timely Pap smears and appropriate follow-up is important in this population. Presently, early detection and aggressive treatment and follow-up of premalignant lesions offer the best approach to the prevention of cervical cancer.

High-yield expression, purification, and characterization of active, soluble Bacteroides fragilis metallo-beta-lactamase, CcrA.

The gene from Bacteroides fragilis encoding a metallo-beta-lactamase, ccrA, was expressed in Escherichia coli BL21(DE3) containing the wild-type disulfide bond-catalyzing system dsb as an active, soluble enzyme in quantities exceeding 100 mg/liter using both rich and minimal media. Both the nonfusion and a glutathione S-transferase fusion enzyme lacking the periplasmic signal sequence were purified to homogeneity. Characteristics of the purified nonfusion enzyme are shown to be similar to those of the renatured enzyme previously reported. Thermal denaturation studies using circular dichroism and fluorescence spectroscopy show that CcrA undergoes a transition at approximately 50 degrees C which corresponds to the transition temperature of catalytic activity. The secondary structure of the protein and the catalytic apparatus are thus intimately linked.

4-Methyl-3-oxo-4-aza-5alpha-androst-1-ene-17beta-N-aryl-carboxamides: an approach to combined androgen blockade [5alpha-reductase inhibition with androgen receptor binding in vitro].

4-Aza-5alpha-androstan-3-one 17beta-(N-substituted carboxamides) are potent human type 2 5alpha-reductase (5aR) inhibitors with generally poor binding to the human androgen receptor (hAR). When the 17-amide N-substituent included an aromatic residue, potent dual inhibitors of both type 1 and 2 5aR are produced, but hAR binding remained poor. Tertiary-substituted-17-amides have reduced inhibition of both 5aR isozymes. The addition of an N4-methyl substitutent to the A-ring profoundly increased hAR affinity and the addition of unsaturation to the A-ring (delta1) modestly augmented hAR binding. The unsubstituted carbanilides in the delta1-N4-methyl series show some selectivity for type 1 5aR over the type 2 isozyme, whereas addition of aryl substituents, particularly at the 2-position, increased type 2 5aR binding to provide dual inhibitors with excellent hAR binding, e.g. N-(2-chlorophenyl)-3-oxo-4-methyl-4-aza-5alpha-androst-1-ene-17bet a-carboxamide (9c). Compounds of this type exhibit low nanomolar IC50s for both human 5aR isozymes as well as the human androgen receptor. Kinetic analysis confirms that the prototype 9c displays reversible, competitive inhibition of both human isozymes of 5aR with K(i) values of less than 10 nM. Furthermore, this compound binds to the androgen receptor with an IC50 equal to 8 nM. Compounds in this series are projected to be powerful antagonists of testosterone and dihydrotestosterone action in vivo, with potential utility in the treatment of prostatic carcinoma (PC).

Non-steroidal L-245,976 acts as a classical antiandrogen in vitro.

Non-steroidal antiandrogens have been employed in the management of prostate cancer, but the mechanism of action is unclear due to a lack of good tissue culture models. The growth of a hamster ductus deferens cell line (DDT1) is highly dependent upon the addition of 10 nM testosterone to synthetic serum-free media. We describe a non-steroidal compound N-(4-chlorophenyl)-(Z,Z)-2,3-bis(-cyclopropylmethylene) cyclopentanecarboxamide (L-245976) which antagonizes the action of testosterone on DDT1 cells at 10 microM but exhibits little or no effect on cell growth by itself. This compound also blocks the binding of 3H-dihydrotestosterone (DHT) to the human androgen receptor (AR) with an IC50 of approximately 28 microM. In addition, L-245976 was found to antagonize DHT-dependent transactivation of the AR via the probasin gene promoter at comparable doses with no agonist activity.

HIV in Women: Recognizing the Signs.

The rates of gynecologic disease in HIV-positive women have been shown to be as high as 42%; given this high percentage, a routine GYN exam can be an invaluable opportunity for the detection of subtle signs of HIV infection.