A novel subcutaneous controlled-release amoxicillin degradable implant for extended-interval administration in veterinary medicine

Dosage forms of antimicrobials play a critical role in facilitating the attainment of pharmacokinetic-pharmacodynamic (PK-PD) targets as well as adherence in both veterinary and human medicine. The purpose of this study was to develop and evaluate a controlled-release subcutaneous amoxicillin implant for single-dose therapy of large ruminants such as goats, sheep, and deer. The degradable implant, designed to attain PK-PD targets following single administration, was evaluated for amoxicillin release rate and time-concentration profile. In vitro release studies demonstrated constant-rate release of approximately 40% of amoxicillin content within 96 h. In an in vivo study in goats, serving as a model for target animals, a serum concentration of approximately 0.4 mg/L was achieved within 8 h of implant insertion and maintained for >6 days. In comparison, in control goats given a standard single intramuscular amoxicillin dose of 15 mg/kg, amoxicillin peaked at 1.2 mg/L after 1 h, rapidly dropping to below detection level at 8 h. These results suggest that the proposed implant offers a unique modality for animal caregivers to conveniently administer a full antimicrobial course following a single dose of an efficient PK-PD-optimized dosage form. Furthermore, modifications of implant composition may allow for tailoring of its characteristics to various PK, PD, microbiological, and clinical requirements.

Profiling protein expression and interactions: proximity ligation as a tool for personalized medicine

The ability to detect very low levels of expressed proteins has enormous potential for early diagnostics and intervention at curable stages of disease. An extended range of targets such as interacting or post-translationally modified proteins can further improve the potential for diagnostics and patient stratification, and for monitoring response to treatment. These are critical building blocks for personalized treatment strategies to manage disease. The past few decades have seen a remarkably improved understanding of the molecular basis of disease in general, and of tumour formation and progression in particular. This accumulated knowledge creates opportunities to develop drugs that specifically target molecules or molecular complexes critical for survival and expansion of tumour cells. However, tumours are highly variable between patients, necessitating the development of diagnostic tools to individualize treatment through parallel analysis of sets of biomarkers. The proximity ligation assay (PLA) can address many of the requirements for advanced molecular analysis. The method builds on the principle that recognition of target proteins by two, three or more antibodies can bring in proximity DNA strands attached to the antibodies. The DNA strands can then participate in ligation reactions, giving rise to molecules that are amplified for highly sensitive detection. PLA is particularly well suited for sensitive, specific and multiplexed analysis of protein expression, post-translational modifications and protein-protein interactions. The analysis of this extended range of biomarkers will prove critical for the development and implementation of personalized medicine.

RENAL INSUFFICIENCY FOLLOWING TRYPSIN INJECTION INTO THE RENAL ARTERIES

1. The injection of trypsin into both renal arteries of the dog was found to cause an acute necrosis of large sections of the kidney, an immediate excretory insufficiency, and a transient hypertension. 2. Dogs surviving the acute phase of the trypsin injection, developed a chronic renal excretory insufficiency with no hypertension, despite the severity and duration of the renal excretory insufficiency. 3. The application of a Goldblatt clamp to the renal artery of one of the two kidneys, previously injected with trypsin, led to a rise in blood pressure which returned at once to normal when the ischemic kidney was removed, even though the pre-existing renal excretory insufficiency was augmented. This experience demonstrated unequivocally that chronic renal excretory insufficiency and hypertension are not directly related. 4. The application of a Goldblatt clamp to the renal artery of one kidney and the simultaneous injection of trypsin into the other led to a hypertension. The later removal of the ischemic kidney led to a severe renal excretory insufficiency, at the same time the pre-existing hypertension disappeared. This indicated again that renal excretory insufficiency and renal ischemia produced different phenomena and that the former had no direct relation to hypertension.

STUDIES CONCERNING THE SITE OF RENIN FORMATION IN THE KIDNEY : III. THE APPARENT SITE OF RENIN FORMATION IN THE TUBULES OF THE MESONEPHROS AND METANEPHROS OF THE HOG FETUS

1. Renin was found in both the mesonephric and metanephric kidneys of the smallest hog fetuses examined. These were from 17 to 24 mm. in length in the case of the former, and 25 to 49 mm. in that of the latter. 2. No evidence was found in either type of kidney of juxtaglomerular cells described by Goormaghtigh as the probable site of renin formation. 3. The renin content in both the mesonephros and the metanephros was found to be independent of its arteriologlomerular component but directly dependent upon the number, size, and functional state of the tubular component. It increased in amount with increasing tubular proliferation during the course of embryonic development, and decreased with the progressive tubular atrophy and degeneration incident thereto. 4. The site of renin formation is discussed.

STUDIES CONCERNING THE SITE OF RENIN FORMATION IN THE KIDNEY : IV. THE RENIN CONTENT OF THE MAMMALIAN KIDNEY FOLLOWING SPECIFIC NECROSIS OF PROXIMAL CONVOLUTED TUBULAR EPITHELIUM

1. The administration of tartrate to adult rabbits was found to produce in some of them, a profound and widespread necrosis of the proximal convoluted tubular epithelium without affecting the other portions of the nephrons. 2. The markedly damaged kidneys were found to be almost completely devoid of pressor substance (renin), indicating that in the mammalian kidney, the epithelium of the proximal convoluted tubules is concerned in the formation or storage of renin.

STUDIES CONCERNING THE SITE OF RENIN FORMATION IN THE KIDNEY : I. THE ABSENCE OF RENIN IN THE AGLOMERULAR KIDNEY OF THE MIDSHIPMAN FISH

1. The absence of glomeruli in the kidney of the midshipman fish (Porichthys notatus) is reported. 2. The detection of renin in the glomerular kidney of the carp, the catfish, and the hog, and the apparent absence of this substance in the aglomerular kidney of the midshipman fish suggest that the tubular portion of the mammalian kidney does not produce or store renin.

Antimicrobial-resistant faecal Escherichia coli in wild mammals in central Europe: multiresistant Escherichia coli producing extended-spectrum beta-lactamases in wild boars

AIMS

To determine the presence of antibiotic-resistant faecal Escherichia coli in populations of wild mammals in the Czech Republic and Slovakia.

METHODS AND RESULTS

Rectal swabs or faeces collected during 2006-2008 from wild mammals were spread on MacConkey agar and MacConkey agar containing 2 mg l(-1) of cefotaxime. From plates with positive growth, one isolate was recovered and identified as E. coli. Susceptibility to 12 antibiotics was tested using the disk diffusion method. Resistance genes, class 1 and 2 integrons and gene cassettes were detected in resistant isolates by polymerase chain reaction (PCR). Extended-spectrum beta-lactamases (ESBL) were further characterized by DNA sequencing, macrorestriction profiling and determination of plasmid sizes. Plasmid DNA was subjected to EcoRV digestion, transferability by conjugation and incompatibility grouping by multiplex PCR. The prevalence of resistant isolates was 2% in small terrestrial mammals (rodents and insectivores, n(E. coli) = 242), 12% in wild ruminants and foxes (n(E. coli) = 42), while no resistant isolates were detected in brown bears (n(E. coli) = 16). In wild boars (Sus scrofa) (n(E. coli) = 290), the prevalence of resistant isolates was 6%. Class 1 and 2 integrons with various gene cassettes were recorded in resistant isolates. From wild boars, five (2%, n(rectal smears) = 293) multiresistant isolates producing ESBL were recovered: one isolate with bla(CTX-M-1) + bla(TEM-1), three with bla(CTX-M-1) and one with bla(TEM-52b). The bla(CTX-M-1) genes were carried on approx. 90 kb IncI1 conjugative plasmids.

CONCLUSIONS

Antibiotic-resistant E. coli occurred in populations of wild mammals in various prevalences.

SIGNIFICANCE AND IMPACT OF THE STUDY

Wild mammals are reservoirs of antibiotic-resistant E. coli including ESBL-producing strains which were found in wild boars.

The recurrent coronary prevention project. Some preliminary findings

The Recurrent Coronary Prevention Project (RCPP) was established as a 5-year clinical trial to examine two basic questions: --1. Can the recurrence rate of post-coronary subjects be substantially reduced over a 5-year period by means of a programme of behavioural change, in comparison with treatment by cardiologists focussing on medication, diet, exercise and cardiovascular issues, and with subjects who only receive regular care from their own physician? 2. Can the Type A behaviour pattern (TABP) be changed and do such changes correspond to reduced recurrences of coronary heart disease (CHD) over a 5 year period? To answer these questions, four major treatment groups are currently being compared: --1. A small group treatment programme (Section I) led by cardiologists emphasizing adherence to medication, diet and exercise, and giving cardiovascular and cardiological information. 2. A behavioural change treatment programme (Section II) based primarily on a cognitive social learning model and attempting to alter TABP. 3. A control group of subjects assessed annually and receiving private medical care from their own physicians. 4. A dropout comparison group composed of subjects voluntarily discontinuing participation in groups led by cardiologists or in behavioural change groups. Results to date show a significantly reduced rate of recurrence for subjects in the behavioural change group, compared to those in the groups led by cardiologists as well as control and dropout groups. These significantly lower recurrence rates are accompanied by data suggesting that subjects in the behavioural change programme are also altering their TABP as measured by both behavioural questionnaires and videotaped Type A structured interviews. Clinical impressions suggest that treatment programmes to alter TABP should consider the primary importance of the personal meaning of the TABP and other behaviours to the individual concerned, particularly how basic underlying beliefs set the stage for the TABP. The central role of hostility as a pervasive orientation towards self and others is emphasized, as are issues of excessive controllability related to extreme competitiveness and hyper-arousal. The multiple roles of group leaders, especially as social models for coping, and the impact of the small groups settings, is also discussed.

Measurement of the energy distribution of an intense electron beam in an external magnetic field

An energy analyzer device has been developed which utilizes a series of stacked foils and Rogowski current monitors to the measure time resolved current of an intense electron beam. The energy distribution of the electron beam is unfolded from measured current ratios using computer simulations. This device is particularly useful where electron beams are guided by external magnetic fields which may make other electron energy measurement techniques difficult. This technique was used to determine the energy distribution of a 550 keV, 95 kA electron beam as it propagates in the gas mixture of a high power KrF laser. The resulting energy distributions at various depths in the gas are in agreement with three-dimensional particle-in-cell simulations providing confidence in the measurement technique.

Reactions of proteins with ethyl vinyl sulfone

Ethly vinyl sulfone (EVS) alkylates xi-amino groups of lysine side chains and imidazole groups of histidine residues in proteins. Amino acid analysis of hydrolyzates of EVS-treated polylysine shows that lysine forms two derivatives, presumably xi-N-(ethylsulfonylethyl)lysine and xi, xi, N,N-bis(ethylsulfonylethyl)lysine that are eluted as well-resolved peaks on the (long basic) physiological column of our amino acid analyzer at about 118 and 60 min, respectively. Peaks with identical elution times were also observed after EVS-treatment of BSA and wool. The postulated histidine derivative, presumably N3-im-(ethylsulfonylethyl)histidine is also eluted as a well-resolved peak on the same column at about 90 min. A peak with an identical elution time was observed in a hydrolyzate of EVS-treated polyhistidine. The described alkylation has potential utility for modifying proteins.

Relative reactivities of sulfhydryl groups with N-acetyl dehydroalanine and N-acetyl dehydroalanine methyl ester

The reaction rates in aqueous solutions of aminothiols, thiols, and other compounds with N-acetyl dehydroalanine and its methyl ester (2-acetamindoacrylic acid and methyl 2-acetamidoacrylate) were studied as a function of the structure of the thiol compound in aqueous solutions. Correction of the observed second-order rate constants to identical thiol anion concentration gave a series of computed rate constants whose logarithms showed a linear dependence on the pK's of the thiol group in similar steric environments. Comparison of the addition rates of penicillamine to N-acetyl dehydroalanine and its methyl ester showed the methyl ester to react approximately 11,400 times faster than the acid. Addition rates for thiol acids and aromatic and heterocyclic thiols were also compared; each showed sluggish reactivity with dehydroalanine, but each reacted readily with methyl dehydroalanine. The kinetic data were applied in developing a method for preparing lanthionine in high yield.