Beta-lactams and beta-lactamase-inhibitors in current- or potential-clinical practice: a comprehensive update

The use of successive generations of beta-lactams has selected successive generations of beta-lactamases including CTX-M ESBLs, AmpC beta-lactamases, and KPC carbapenamases in Enterobacteriaceae. Moreover, this cephalosporin resistance, along with rising resistance to fluoroquinolones, is now driving the use of carbapenems and unfortunately the carbapenem resistance has emerged markedly, especially in Acinetobacter spp. due to OXA- and metallo-carbapenemases. The industry responded to the challenge of rising resistance and recently developed some novel beta-lactams such as ceftobiprole, ceftaroline etc. and many beta-lactam compounds, including beta-lactamase-inhibitors, such as BMS-247243, S-3578, RWJ-54428, CS-023, SMP-601, NXL 104, BAL 30376, LK 157, and so on are under trials. This review provides the comprehensive accounts of the developments in penicillins, cephalosporins, carbapenems, and beta-lactamase-inhibitors, and the insight about medicinal chemistry, mechanism(s) of action and resistance, potential strategies to overcome resistance due to beta-lactamases, and also the recent advancements in the development of newer beta-lactam compounds; some of which are still under trials and yet to be classified. This review will fill the gap since previously published reviews and will serve as a comprehensive update on the current topic.

Characterization of germanium linear kinoform lenses at Diamond Light Source

The unprecedented brilliance achieved by third-generation synchrotron sources and the availability of improved optics have opened up new opportunities for the study of materials at the micrometre and nanometre scale. Focusing the synchrotron radiation to smaller and smaller beams is having a huge impact on a wide research area at synchrotrons. The key to the exploitation of the improved sources is the development of novel optics that deliver narrow beams without loss of brilliance and coherence. Several types of synchrotron focusing optics are successfully fabricated using advanced miniaturization techniques. Kinoform refractive lenses are being developed for hard X-ray beamlines, and the first test results at Diamond are discussed in this paper.

Lipoxygenase inhibitory tetraketones: potential remedial source for inflammation and asthma

OBJECTIVE

A series of tetraketones has been synthesized by way of a one pot synthesis and screened for inhibitory activity against the enzyme lipoxygenase.

METHOD

An efficient and high yielding one pot synthesis to tetraketones [2-22] has been developed by way of tetraethyl ammonium bromide (Et4N+Br-) mediated condensation of cyclohexane-1, 3-dione [1] with a variety of aldehydes. Lipoxygenase enzyme solution was prepared so that enzyme concentration in reaction mixture was adjusted to give rates of 0.05 absorbance/minute. The test compounds were prepared in methanol of concentrations 50, 25, 12.5, 6.25 and 3.125 microM. The reaction mixture contained 160 microL (100 mM) sodium phosphate buffer (pH 8.0), 10 microL of test-compound solution and 20 microL of lipoxygenase solution. The contents were mixed and incubated for 10 minutes at 25 degrees C. The reaction was then initiated by the addition of 10 microL substrate solution (linoleic acid, 0.5 mM, 0.12% w/v tween 20 in the ratio of 1:2), with the formation of (9Z, 11E)-(13S)-13-hydroperoxyoctadeca-9,11-dienoate, the change of absorbance at 234 nm was followed for 6 minutes. The concentrations of the test compounds that inhibited the lipoxygenase activity by 50% (IC50) were determined by monitoring the effect of increasing concentrations of these compounds in the assays on the degree of inhibition. The IC50 values were calculated by means of the EZ-Fit Enzyme-Kinetics Program (Perrella Scientific Inc., Amherst, U.S.A.).

RESULT

The tetraketones [2-22] were synthesized in high yields (91-98%) using mild reaction conditions. Most of these compounds showed significant inhibitory activity against the enzyme lipoxygenase. It was found that the presence of substituents which increase delocalization of electrons enhances the inhibitory activity.

CONCLUSION

It is concluded that the study is likely to lead to the discovery of therapeutically efficient agents against important disorders such as inflammation and asthma.

The Prevalence of Self-Reported Halitosis and Oral Hygiene Practices among Libyan Students and Office Workers

AIMS

The aims of this study were to assess the prevalence of self-reported halitosis, oral hygiene practices and related diseases among Libyan students and employees.

METHODS

Six hundred self-administered structured questionnaires were used to investigate self-perception of halitosis and oral hygiene practices among a group of Libyan volunteers. Chi square test was used to detect significant differences between frequencies and to test correlation between self-perception of halitosis and measures of oral hygiene.

RESULTS

Forty three percent of the subjects were males and 57% were females. Forty four percent of the males and 54% of the females revealed self-perception malodour. Malodour was reported with the highest frequency (68%) during wake up time. Malodour was perceived by 31.7% of the females and 23.4% of the males during the hand-on-mouth test (p=0.04). Significantly more females (89.9%) than males (75.7%) practiced brushing (p<0.001). Fifty one percent of the males and 49.6% of females had dental caries. Smoking was significantly (p<0.001) more prevalent among males (17%) than among females (1%). Brushing was practiced by 85% of non-smokers and 68% of smokers (p=0.004). About 71% of the subjects who practiced brushing reported malodour during wake up time in comparison to subjects who did not practice brushing (p=0.041).

CONCLUSIONS

The prevalence of self-perceived malodour among the Libyan volunteers in this study is within the range of other studies. There is a great demand to reduce the incidence of dental caries and periodontal diseases.

Laparoscopic resection for colorectal cancer

BACKGROUND

This study examined one surgeon's practice to determine the place of laparoscopic colorectal cancer surgery.

METHODS

Some 365 patients undergoing elective colorectal cancer resection (219 colonic, 146 rectal) were studied prospectively. Early (1994-1997; 104 patients), middle (1998-2001; 112) and late (2002-2005; 149) cohorts were analysed with respect to suitability for laparoscopic surgery, conversion and outcome.

RESULTS

Forty-six of 135 patients undergoing open resection were suitable for laparoscopic surgery but randomized to open surgery. The proportion of attempted laparoscopic resections (35.6, 65.2 and 80.6 per cent in early, middle and late cohorts) and patients thought suitable for laparoscopic resection (37.5, 87.5 and 94.0 per cent respectively; P = 0.001) increased over time. Independent predictors of conversion were rectal cancer surgery (odds ratio (OR) 3.12 versus colonic surgery) and body mass index 28 kg/m(2) or more (OR 3.87). Conversion was necessary in all five patients with a threatened margin predicted by preoperative magnetic resonance imaging. After exclusion of these patients the conversion rate in the late cohort was 8.7 per cent. During the same period, inclusion of 20 patients who were suitable for laparoscopic surgery but underwent open resection meant that 135 (90.6 per cent) of 149 patients were actually suitable for laparoscopic resection.

CONCLUSION

With experience, laparoscopic surgery is feasible in around 90 per cent of elective colorectal cancer resections.

Conjugative plasmids in multi-resistant bacterial isolates from Indian soil

AIMS

Determination of heavy metal and antibiotic resistance and presence of conjugative plasmids in bacteria isolated from soil irrigated with wastewater.

METHODS AND RESULTS

Composite soil samples were collected from Ghaziabad, Uttar Pradesh, India. Forty different bacteria were selected from nutrient agar and characterized by morphological, cultural and biochemical tests. All the isolates were tested for their resistance to different heavy metals and antibiotics. The DNA derived from multiple metal and antibiotic-resistant bacterial isolates was PCR amplified and plasmid-specific sequences (IncP, IncN, IncW, IncQ and pMV158-type) were analysed by dot blot hybridization. All isolates gave PCR products with trfA2 and oriT primers of the IncP group. These PCR products also hybridized with the RP4-derived probes. However, the samples were negative for all the other investigated plasmids as proved by PCR and dot blots.

CONCLUSIONS

The presence of conjugative/mobilizable IncP plasmids in the isolates indicates that these bacteria have gene-mobilizing capacity with implications for potential dissemination of introduced recombinant DNA.

SIGNIFICANCE AND IMPACT OF THE STUDY

The detection of IncP plasmids in all the bacterial isolates is another proof for the prevalence of these plasmids. We propose that IncP plasmids are mainly responsible for the spread of multi-resistant bacteria in these soils.

Comparative features and outcomes of malaria at a tertiary care hospital in Karachi, Pakistan

OBJECTIVES

A comparison of clinical and laboratory features, diagnostic methods, drug treatment, and outcomes for patients hospitalized with malaria by Plasmodium species.

METHODS

Records of 521 patients hospitalized during the four and half-year study period were analyzed.

RESULTS

Infections were caused by Plasmodium vivax (51.8%), Plasmodium falciparum (46.5%), P. vivax plus P. falciparum (1.3%), and Plasmodium malariae (0.4%). Vomiting (odds ratio (OR)=1.86, p=0.001) and abdominal pain (OR=1.60, p=0.024) occurred more frequently in patients infected with P. falciparum compared to P. vivax; this was also the case for hepatomegaly, splenomegaly and jaundice. Low hemoglobin levels were common but were significantly lower with P. falciparum, and creatinine levels were significantly higher with P. falciparum. Treatment regimens consisted of single drug therapy (61.5%), appropriate combination therapy (15.8%), and inappropriate combination therapy (22.7%). Antimalarials given alone included chloroquine (38.7%), quinine (19%) and doxycycline (1.5%). The overall mortality was 1.7% (n=9) and nearly 56% of patients developed disease complications, most commonly thrombocytopenia (36.4%), anemia (23.4%), and thrombocytopenia plus anemia (32.7%).

CONCLUSIONS

Despite resistance, chloroquine was prescribed in patients with malaria requiring hospitalization. We found a high proportion of single antimalarial drug use as well as inappropriate combination therapy (22.7%), and inadequate use of primaquine terminal prophylaxis. Physicians need to be acquainted with malaria treatment guidelines in an endemic zone.

Multiple sclerosis in Pakistan

We describe retrospective data from the largest series of patients (n=142) with multiple sclerosis (MS) from Pakistan. Mean age at onset was 27 years, with a female to male ratio of 1.45:1. The disease onset was polysymptomatic in 75% patients. Motor weakness was the most common onset symptom (70%), followed by sensory symptoms (45%). Optico-spinal type of MS was seen in only 3% of patients The courzse was relapsing-remitting (RR) in 81%, primary progressive (PP) in 21%, and secondary progressive (SP) in 4% of patients. Almost three-fourths of the patients were moderately (45%) or severely (31%) disabled at the time of evaluation. Two-thirds of patients with severe disability had a mean disease duration of only 5.2 years. In conclusion, MS is not uncommon in Pakistan, and many patients were found to have severe disability despite short disease duration. Multiple Sclerosis 2007; 13: 668-669. http://msj.sagepub.com

Fournier's gangrene and its emergency management

Fournier's gangrene (FG) is a rare but life threatening disease. Although originally thought to be an idiopathic process, FG has been shown to have a predilection for patients with diabetes as well as long term alcohol misuse; however, it can also affect patients with non-obvious immune compromise. The nidus is usually located in the genitourinary tract, lower gastrointestinal tract, or skin. FG is a mixed infection caused by both aerobic and anaerobic bacterial flora. The development and progression of the gangrene is often fulminating and can rapidly cause multiple organ failure and death. Because of potential complications, it is important to diagnose the disease process as early as possible Although antibiotics and aggressive debridement have been broadly accepted as the standard treatment, the death rate remains high.

Chemistry of isocoumarins: synthesis and biological screenings of Homalicine and dihydrohomalicine

Total synthesis and selected biological activities of naturally occurring homalicine and (dl)-dihydrohomalicine are described.

Endoluminal and transluminal surgery: current status and future possibilities

The field of minimally invasive surgery has seen tremendous growth since the first laparoscopic cholecystectomy was performed in 1987. The key question is not how successful these techniques are currently, but rather where may they lead in the future? New technologies promise to usher in an era of even less invasive procedures. The terms being coined in the literature include "incisionless," "endoluminal," "transluminal," and "natural orifice" transluminal endoscopic surgery. These techniques certainly have the potential to become the next wave of minimally invasive procedures. A recent editorial in Surgical Endoscopy by Macfadyen and Cuschieri highlighted the ongoing developments in endoscopic surgery and stressed the critical importance of surgeons being involved in future applications and permutations of these techniques [1]. There are early signs of such involvement. The work of numerous investigators in the field was presented recently at the 2005 Digestive Disease Week. The American Society for Gastrointestinal Endoscopy and the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES), in collaboration with the American College of Surgeons, recently organized a postgraduate course in endoluminal therapy at the spring 2005 meeting held in Hollywood, Florida. The course is being offered again at the 2006 SAGES annual meeting. Similar courses are being offered at other regional and national meetings. This review attempts to highlight some of the available and evolving endoluminal therapies reviewed at that forum, including techniques for the management of gastroesophageal reflux disease, endoscopic mucosal resection, endoluminal bariatric surgery, transanal endoscopic microsurgery, and transgastric endoscopic surgery, as well as new technologies and possible future directions in luminal access surgery.

Phenotypic and genetic characterization of enteropathogenic Escherichia coli (EPEC) and entero-aggregative E. coli (EAEC) from diarrhoeal and non-diarrhoeal children in Libya

A total of 50 Escherichia coli strains isolated in a Libyan hospital (20 from children with diarrhoea and 30 from healthy children) were investigated for their pathotypes and virulence traits. Altogether nine eae-positive (enteropathogenic E. coli, EPEC) and nine aggR-positive (entero-aggregative E. coli, EAEC) strains were identified. Significantly (P=0.001) more EPEC strains were identified from diarrhoeal patients (n=8) than from healthy controls (n=1), while six EAEC strains were identified from diarrhoeal and three from healthy children. Typical (eae(+), EAF(+), bfp(+)) EPEC strains (n=6) belonged to classical EPEC serogroups O55, O114, O127 and showed localized adherence on Hela cells. EAEC strains revealed genetic heterogeneity but uniformly adhered to HeLa cultures in an entero-aggregative adherence pattern. Antibiotic resistance frequently, characterized the strains. Sixty-eight percentage of the strains were resistant against at least one antibiotic and 30% harbored a class 1 integron independently of their clinical background. This is the first report from North Africa demonstrating the significance of EPEC and EAEC.

Tyrosinase inhibitory lignans from the methanol extract of the roots of Vitex negundo Linn. and their structure-activity relationship

Phytochemical investigation of the methanol extract of Vitex negundo afforded eight lignans; negundin A 1, negundin B 2, 6-hydroxy-4-(4-hydroxy-3-methoxy)-3-hydroxymethyl-7-methoxy-3,4-dihydro-2-naphthaledehyde 3, vitrofolal E 4, (+)-lyoniresinol 5, (+)-lyoniresinol-3alpha-O-beta-d-glucoside 6, (+)-(-)-pinoresinol 7, and (+)-diasyringaresinol 8. The structures of these compounds were elucidated unambiguously by spectroscopic methods including 1D and 2D NMR analysis and also by comparing experimental data with literature data. The tyrosinase inhibitory potency of these compounds has been evaluated and attempts to justify their structure-activity relationships have been made in the present work. The compound 5 was found to be the most potent (IC(50)=3.21 microM) while other compounds demonstrated moderate to potent inhibitions. It was found that the substitution of functional group(s) at C-2 and C-3 positions and the presence of the -CH(2)OH group plays a vital role in the potency of the compounds. The compound 5 can act as a potential lead molecule to develop new drugs for the treatment of hyperpigmentation associated with the high production of melanocytes.