Criteria for diagnosis of urinary tract infection and evaluation of therapy

Patients with urinary tract infections are commonly used to study the efficacy of new antibiotics. Some criteria, for example the presence of more than 100,000 organisms of a single species per ml as an indicator of infections, have been accepted for many years but all rules have exceptions. Other criteria such as relapse, re-infection are less clearly agreed. Furthermore, timing of collection of specimens during and after treatment shows great variation in protocols and in definition. These criteria and the methodology of collecting, transportation and examination of urine are discussed.

Isolation and characterization of a membrane protein from rat erythrocytes which inhibits lysis by the membrane attack complex of rat complement

The membrane attack complex (MAC) of complement in humans is regulated by several membrane-bound proteins; however, no such proteins have so far been described in other species. Here we report the isolation and characterization of a rat erythrocyte membrane glycoprotein of molecular mass 21 kDa which inserts into cell membranes and is a potent inhibitor of the rat MAC. This protein, here called rat inhibitory protein (RIP), was first partially purified by column chromatography from a butanol extract of rat erythrocyte membranes. Monoclonal antibodies (Mabs) were raised against RIP and used for its affinity purification. Affinity-purified RIP was shown to inhibit in a dose-dependent manner the cobra venom factor (CVF)-mediated 'reactive' lysis of guinea pig erythrocytes by rat complement. Conversely, the anti-RIP MAbs 6D1 and TH9 were shown to markedly enhance the CVF-mediated lysis of rat erythrocytes by rat complement. RIP acted late in the assembly of the MAC (at or after the C5b-8 stage) and was releasable from the membranes of rat erythrocytes by phosphatidylinositol-specific phospholipase C. These features, together with its size, deglycosylation pattern and N-terminal amino acid sequence, lead us to conclude that RIP is the rat homologue of the human MAC-inhibitory protein CD59 antigen.

Antimicrobial resistance in Haemophilus influenzae from England and Scotland in 1991

Twenty-two laboratories in England and Scotland sent 2212 clinical isolates of Haemophilus influenzae to The London Hospital Medical College (LHMC) between 1 January and 31 March 1991. After confirmation of identity, the prevalence of resistance was determined and compared with results from previous similar surveys. beta-Lactamase was produced by 8.3% of non-capsulate isolates and 21% of 52 type b isolates; both figures were higher than the 6% and 18% figures recorded, respectively, in 1986. There was an increase in the prevalence of non-beta-lactamase-mediated diminished susceptibility to ampicillin (5.8%) and co-amoxiclav (6.1%) compared with 1986 (4%). Whereas fewer H. influenzae isolates were resistant to tetracycline (1.4%) or chloramphenicol (0.8%), there was an increase in resistance to trimethoprim (6.8%) and to sulphamethoxazole (16.9%) compared with 1986 (4.2% and 3.5% respectively). In addition, 95 isolates (4.3%) were resistant to both of these anti-folate antimicrobials. Six isolates (one type b from CSF) were resistant to all drugs tested, except for co-amoxiclav. Overall, the results demonstrated that changes have occurred in the last decade in England and Scotland, such that H. influenzae isolates are increasingly likely to be resistant to ampicillin, co-amoxiclav and co-trimoxazole.

Profile of bronchial responsiveness in children with respiratory symptoms

A postal questionnaire inquiring into the presence of respiratory symptoms was sent to 3698 children aged 7 and 8 years. Those reporting either cough or wheeze were randomised, and a sample invited to attend for skin testing. A total of 192 symptomatic children, half of whom were atopic and half non-atopic, were randomly selected to enter the study. All children performed and recorded best of three peak expiratory flow measurements twice a day and completed a 10 point respiratory symptom score card each day for one year. They also recorded all treatment taken and made a note of relevant life events. Each child was seen monthly for general assessment and for measurement of nonspecific bronchial responsiveness to methacholine. Of the 192 children, 183 successfully completed the study. For six subjects 11 measurements of the provocation dose required to cause a 20% fall in forced expiratory volume in one second (PD20) were available for analysis and on the remaining 177, greater than or equal to 12 measurements. The prevalence and degree of bronchial hyper-responsiveness (PD20 less than 6.4 mumol) and its relationship to atopy was examined by comparing the percentage of members of each symptom group demonstrating bronchial hyper-responsiveness and the number of occasions on which they did so, and by comparison of minimum and median PD20 values. The range of bronchial responsiveness shown during the study period by each child was expressed as doubling doses of methacholine and compared between symptom groups. Atopy and wheeze were both independently associated with an increased prevalence and greater degree of bronchial hyper-responsiveness when compared with non-atopy and cough respectively, all differences being significant a the 0.001 level.. Thirty three per cent of subjects demonstrated a rnge of methacholine responsiveness of >4 and 13.4% of >6 doubling doses during one year.

Renal hemodynamics in newly presenting non-insulin dependent diabetes mellitus

Little information is available regarding renal hemodynamics in non-insulin dependent diabetics (NIDDMs), despite their numerical significance to renal support programs. Therefore, simultaneous determination of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) (expressed to 1.73 m2 surface area) was performed in 110 newly presenting normotensive NIDDMs [mean (SD) age: 52.5 (10.1) years] and compared with 32 normal subjects of similar age range [age: 52.2 (11.3) years]. Mean (SD) GFR, ERPF and filtration fraction (FF) for the NIDDMs were: 117 (22) ml/min (range: 74 to 178), 534 (123) ml/min and 22.4 (3.0)%, and for the normals: 95 (12) ml/min (range: 75 to 119), 472 (70) ml/min and 20.2 (2.2%), respectively. As a group, NIDDMs demonstrated significantly greater GFR (P less than 0.001), ERPF (P less than 0.005) and FF (P less than 0.001). GFR values above 140 ml/min were observed in 16% of the NIDDMs, while 45% had GFRs in excess of mean +/- 2 SD of the normals. NIDDMs demonstrated a positive relationship for GFR with ERPF (P less than 0.001) and an inverse association for both GFR and ERPF with age (P less than 0.001). Multivariable regression analysis revealed ERPF as the strongest explanatory variable for GFR in the NIDDMs (P less than 0.001), followed by age (P less than 0.01). Significant contributions to the regression analysis were not observed for body mass index, systolic or diastolic blood pressures, glycosylated hemoglobin nor fasting levels of plasma glucose, cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides. Urinary albumin excretion rates were not correlated with GFR, ERPF or FF. Microalbuminuria was detected in 7% of the NIDDMs in this study.(ABSTRACT TRUNCATED AT 250 WORDS)

An audit of appropriate tests in renal biopsy coagulation screens

Hematological, biochemical, and clinical data was collected over a 15-month period on all adult (greater than 16 years) patients assessed for percutaneous biopsy of native kidneys in a major renal unit. The frequency, causes, interrelationships, and treatment of the abnormalities, along with factors resulting in delay or cancellation of renal biopsies were subsequently subjected to audit. Overall, 30 of 147 coagulation screens were abnormal. The most common coagulopathy was a prolonged bleeding time (BT), which accounted for 58.6% of these. A prolonged BT was not clearly related to other hematological or biochemical indices, and proved to be treatable with arginine vasopressin (DDAVP). The majority of abnormalities occurred in isolation (23/30), and eight of 30 were related directly to current anticoagulant or antiplatelet medication. All but two patients with abnormalities proceeded to renal biopsy after successful corrective measures, but 21 of 30 were delayed by between 1 hour and 14 days. None of the remaining 117 biopsies were delayed, although seven were cancelled for a variety of reasons. The prothrombin consumption index provided no additional useful management information. Our clotting screen, modified by this audit, should safely and efficiently detect clotting abnormalities before renal biopsy.

Effect of dialyser composition and reuse on neutrophil count and elastase alpha-1 proteinase inhibitor complex formation

To assess the inter-relationship of leucopenia and PMN elastase release we undertook a prospective crossover study of 6 patients dialysed with new and reused cuprophane, cellulose acetate and polysulfone membranes. Serial blood samples were analysed for PMN count, and elastase-alpha 1-proteinase inhibitor complex (E alpha 1PI) concentrations. After 15 min dialysis with new membranes median PMN counts fell by 72.2%, 25.3% and 22.1% with cuprophane, cellulose and polysulfone, respectively. With reuse the decreases were reduced to 6.4%, 8% and 13.6%. All membranes produced a gradual increase of E alpha 1PI. Median E alpha 1PI accumulation rates (ng ml-1 min-1) with new membranes were 175, 169 and 187 for cuprophane, cellulose acetate and polysulfone, respectively. With reuse of cuphrophane and cellulose acetate these rates fell to 99 and 109 (p less than 0.05 and p less than 0.05, respectively), however, with polysulfone it remained unchanged at 180 ng ml-1 min-1. This study highlights differences between two aspects of the neutrophil response to haemodialysis, and demonstrates that extrapolation from individual parameters to conclusions concerning biocompatibility may be inappropriate.

A comparison of injectable anaesthetic regimens in Mammoth asses

Xylazine (1.1 mg/kg body weight [bwt])-ketamine (2.2 mg/kg bwt) (X/K) anaesthesia was evaluated, in nine Mammoth asses, for effectiveness and compared with two other injectable anaesthetic combinations: xylazine (1.1 mg/kg bwt)-butorphanol (0.044 mg/kg bwt)-ketamine (2.2 mg/kg bwt) (X/B/K); and xylazine (1.1 mg/kg bwt)-tiletamine-zolazepam (1.1 mg/kg bwt) (X/T). All drugs were given intravenously (i.v.). Heart rate, respiratory rate, systolic blood pressure, arterial blood pH, PCO2, PO2, recumbency time and number of attempts to stand were measured. Quality of induction and recovery, muscle relaxation and response to stimulus were evaluated subjectively. One animal did not become recumbent with X/K. Recumbency times were significantly (P < 0.05) different: the shortest time was with X/K (24 mins) and the longest time with X/T (46 mins), with X/B/K, it was 37 mins. Assess required significantly more attempts to stand with X/T (n = 3) than with X/K (n = 1) or X/B/K (n = 2). No significant differences in heart rate, respiratory rate, blood pressure, arterial PO2 or PCO2 were detected between groups. Arterial pH was significantly lower at 15 mins in the X/B/K and X/T groups than in the X/K group. Although X/K generally produced effective immobilisation, the combinations of X/B/K and X/T, appeared to be more satisfactory and relatively safe, and provided longer recumbency times and increased muscle relaxation compared with X/K.

Protein kinase C activation modulates tumour necrosis factor-alpha priming of human neutrophils for zymosan-induced leukotriene B4 release

Neutrophil (PMN) activation by the yeast component zymosan involves the complement receptor type 3 (CD11b/CD18). Recombinant human tumour necrosis factor-alpha (rhTNF-alpha) augmented the zymosan-stimulated leukotriene B4 (LTB4) release from PMN, reaching a fourfold increase at 10(-9) M. Co-incubation of PMN with 10(-9) M rhTNF-alpha and staurosporine resulted in a further dose-dependent increase, which became significantly greater than a purely additive effect at a staurosporine concentration of 10 nM. This synergy was maintained at all doses of staurosporine tested. In addition, doses of phorbol 12-myristate 13-acetate (PMA) that do not activate protein kinase C (PKC) (below 10(-9) M) also augmented the zymosan-stimulated release of LTB4. However, doses of PMA above 10(-9) M progressively inhibited the response to levels below that of zymosan alone. Staurosporine at 50 nM completely prevented, and 10(-9) M rhTNF-alpha partially but significantly (P less than 0.02 at 10(-8) M PMA, P less than 0.01 at 10(-7) M PMA) reversed, this high-dose PMA inhibition. PKC activation thus opposes the priming effect of rhTNF-alpha on neutrophils, while PKC inhibition may enhance the ability of rhTNF-alpha to prime PMN for zymosan activation. The combined effect of rhTNF-alpha and staurosporine suggests an intracellular synergy rather than simply a direct action due to increased zymosan receptor expression. Thus there appear to be mechanisms whereby the responses of neutrophils may be augmented without activating PKC. Indeed, kinase activation may even exert a degree of feedback control that is antagonized by rhTNF-alpha treatment.

A comparison of injectable anaesthetic regimens in mules

Three combinations of injectable anaesthetic agents were compared in nine adult mules. The combinations were xylazine/ketamine (X/K), xylazine/butorphanol/ketamine (X/B/K), and xylazine/tiletamine-zolazepam (X/T). Measured variables were heart rate, respiratory rate, systolic blood pressure, arterial blood pH, PCO2 and PO2, recumbency time and number of attempts to stand. Quality of induction and recovery, muscle relaxation and response to stimulus were evaluated subjectively. Recumbency time was significantly (P < 0.05) longer with X/B/K and X/T than with X/K. Mules required significantly more attempts to stand under the influence of X/T than X/K or X/B/K. No statistically significant (P < 0.05) differences in heart rate, respiratory rate, blood pressure or arterial pH, PCO2 and PO2 were detected between groups.

A comparison of end-tidal halothane concentrations measured at proximal and distal ends of the endotracheal tube in the horse

Measurements (n = 126) of end-tidal halothane concentrations were taken from 21 horses anesthetized for routine and emergency surgery. One hundred five paired values allowed comparison of gas samples taken near the oral end of the endotracheal tube (Y1) to samples obtained at the cuffed end of the endotracheal tube (Y2). Twenty-one paired readings were assessed to compare samples taken 25 cm beyond the cuffed end of the tube (Y3) to samples from Y1. Measurements were made at all locations at 15-minute intervals starting 30 minutes after beginning halothane. All measurements were made in triplicate at end-expiration, and both sites were sampled within 1 minute of each other. Halothane concentration was measured by rapid infrared analysis with a gas sampling rate of 150 ml/min and displayed as a digital reading. Calibration of the machine was checked regularly. The difference between readings (Y1-Y2 or Y1-Y3 = Sdif) was tested using general linear models and a significance level of p less than 0.05 was used. The variable Sdif was analyzed with respect to time, mode of ventilation, and type of recumbency; no effects of these variables were detected. The mean values (+/- SD) of 105 readings for Y1 and Y2 were 2.41 vol% (+/- 0.49) and 2.39 vol% (+/- 0.49) respectively, and the Pearson's correlation coefficient (Y1 vs Y2) was 0.96. The mean values (+/- SD) of 21 measurements for Y1 and Y3 were 2.31 vol% (+/- 0.27) and 2.32 vol% (+/- 0.28) respectively and the Pearson's correlation coefficient (Y1 vs Y3) was 0.98.

Effect of stage of gestation on efficacy of Brucella abortus strain-19 vaccination in cattle

Seventy-nine cattle in all stages of gestation were inoculated with a low dose (2.5 x 10(8) colony-forming units) of Brucella abortus strain 19, then challenge exposed with pathogenic B abortus strain 2308 during the subsequent gestation. A brucellosis case was defined by isolation of strain 2308 from dam or calf samples. Cumulative incidence of brucellosis cases was 48, 33, 25, or 47% for cattle that were, respectively, not pregnant, or 19 to 87, 100 to 167, or 190 to 253 days in gestation at vaccination. The cumulative incidence was 56% in 27 nonvaccinated controls. The 95% confidence intervals for risk ratios included 1 in all cattle, except those that were 100 to 167 days in gestation at vaccination (ie, second trimester); the confidence interval for this group was 0.21 to 0.97. The prevented fraction (1-risk ratio) attributed to strain 19, in ascending order, was 0.14, 0.16, 0.4, or 0.55, respectively, for cattle that were not pregnant, or were 190 to 253, 19 to 87, or 100 to 167 days in gestation at vaccination. Potential confounders of breed, pen effect, and gestation days at challenge exposure did not significantly affect results. Results supported the hypothesis that stage of gestation at vaccination will affect the prevented fraction of brucellosis, or efficacy of strain 19, in cattle vaccinated with a low dose and, therefore, is one factor that may explain variation in strain 19-induced protection.

Spectrum of activity of azithromycin

In recent years, a number of newer macrolides have been developed. One such antibiotic is azithromycin, which has a 15-membered ring structure and is classed as an azalide. The limitations of erythromycin and the discovery of pathogenic bacteria such as Campylobacter, Legionella and Chlamydia species provide incentives to study the usefulness of newer antibiotics of this class. Azithromycin has good activity against staphylococci, streptococci, Moraxella catarrhalis and other rapidly growing pyogenic bacteria. The good activity of azithromycin against Haemophilus influenzae (MIC90 0.5 mg/l) is particularly important as erythromycin has only marginal activity against this organism. Azithromycin has also been shown to be more potent than the macrolides against Enterobacteriaceae. In common with erythromycin and tetracycline, the agent has good activity against Legionella, Chlamydia and Campylobacter. Opportunistic infections involving Toxoplasma gondii and Pneumocystis carinii are an increasing problem and azithromycin is particularly interesting in view of its activity against these difficult-to-treat organisms.

Effects of stage of gestation and breed on bovine responses to vaccination with Brucella abortus strain 19

Eighty-eight cattle were injected SC with 2.5 x 10(8) viable cells of Brucella abortus strain 19. All but 1 heifer became seropositive on the basis of the results of 7 brucellosis tests, and the proportion positive decreased with time. The proportion of cattle that were seropositive during a 20- to 67-week period after vaccination was as follows, in decreasing order: hemolysis-in-gel, 59%; buffered-acid plate antigen, 39%; ELISA, 16%; card, 10%; rivanol, 8%; cold complement-fixation, 7%; and automated complement-fixation, 5%. Using the serologic classification in Uniform Methods and Rules for brucellosis eradication, 7 cattle tested brucellosis-positive (2 suspects and 5 reactors). None of the 27 nonpregnant heifers tested positive. Of 18 heifers that were 84 to 135 days in gestation when vaccinated, 6 (33%) tested positive for brucellosis, compared with 0 of 13 and 1 (3%) of 30 heifers that were 11 to 78 and 145 to 253 days in gestation at vaccination, respectively (X2 = 12.07; 2 df; P less than 0.01). Neither breed (Angus, Hereford, Jersey, and Brahman) nor calf survival was related to brucellosis-positive results. Postpartum milk samples from 61 heifers and 24 tissues from 2 reactor cattle were culture-negative for B abortus.

Age, Cohort and Period in Life-Span Research: A Three-Way Analysis with Logically Missing Cells

A solution is shown for addressing the age x cohort x period issue in life-span research. Previous solutions have utilized only portions of the data in a given two-way layout. The proposed solution uses all data, which for at least two of the three two-way layouts involves missing cells. The method can be used for repeated measure designs, or designs in which new subjects are measured at each period. The design allows the assessment of each main effect and each two-way interaction. The hypotheses tested are explicitly shown, together with the linear models that accomplish this testing.

Failure of two macrolide antibiotics to prevent post-extraction bacteraemia

Two macrolide antibiotics, erythromycin and josamycin, were compared in a double-blind trial to examine their efficacy in the prevention of post-dental extraction bacteraemia in a group of healthy patients. An in vitro blood culture system was used. Isolates of streptococci were identified to species level. Minimum inhibitory concentrations (MICs) of erythromycin and of josamycin for each isolate were estimated by an agar dilution technique, with controls. Levels of drug in the serum of volunteers and of patients were assayed after oral doses of the macrolide antibiotics. Levels found achieved early peaks and satisfactory concentrations for activity against streptococci. Within the specified parameters, the results demonstrated that the antibiotics failed to prevent survival in blood culture of various strains of streptococci for up to 24 hours following collection of the blood. It is recommended that an alternative antibiotic to either erythromycin or to josamycin be used to achieve prophylaxis against streptococci in infective endocarditis risk patients who are allergic to penicillin.

A population survey of cardiovascular disease in elderly people: design, methods and prevalence results

A cross-sectional survey of an age- and sex-stratified random sample of the elderly population living in Southampton was undertaken with the object of measuring the frequency of cardiovascular disease by questionnaire and examination, and assessing cardiac anatomy and physiological function by noninvasive methods. The response rate was 64% and 259 men and women aged between 65 and 95 years were interviewed and examined and had a twelve-lead ECG and chest radiograph. Forty per cent of men and 47% of women reported a diagnosis of one or more cardiovascular diseases, of which high blood pressure 33%, coronary heart disease 14% (angina pectoris 11% and myocardial infarction 8%), peripheral arterial disease of the lower limbs 7%, and cerebrovascular disease 6% occurred most frequently. With the exception of high blood pressure, which women reported more frequently than men (40% vs 27%), the prevalence of these diagnoses by sex was similar. The self-administered WHO questionnaires gave point prevalence estimates for angina pectoris of 13%, possible myocardial infarction 7% and intermittent claudication 5%, which were similar to reported prevalences of these diseases, although disagreement in the classification of individuals for each disease was common. When comparing the WHO chest pain questionnaire with the doctors' independent diagnosis of angina pectoris in this population, the sensitivity of the WHO questionnaire was 79%, with a specificity of 98% and a predictive value of 88%. For each sex the sensitivity of the WHO chest pain questionnaire was similar but specificity and predictive value were both lower for women.(ABSTRACT TRUNCATED AT 250 WORDS)

Antimicrobial susceptibility of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella (Branhamella) catarrhalis isolated in the UK from sputa

Four hundred and thirty-one Streptococcus pneumoniae, 1272 Haemophilus influenzae and 305 Moraxella (Branhamella) catarrhalis were isolated from sputa and identified in 28 UK laboratories during a ten week period in 1990. Disc diffusion susceptibility testing was performed in each centre using identical methods. Species-specific susceptibility breakpoints applied to data for six antimicrobial agents were determined from the distribution of isolates according to zone diameters of inhibition measured in participating laboratories and were correlated with minimum inhibitory concentration data obtained with 302 isolates sent to the coordinating centre. Inter-laboratory reproducibility was estimated by comparing peripheral and coordinating centre results for these 302 isolates and by distributing five reference strains to all laboratories for testing. Reduced susceptibility to ampicillin and amoxycillin-clavulanate was detected in less than 3% of S. pneumoniae, but 8.1% were resistant to tetracycline and 6.5% to erythromycin. Resistance to ampicillin due to production of beta-lactamase occurred in 9.4% of H. influenzae; another 5.2% were resistant to ampicillin and amoxycillin-clavulanate but were beta-lactamase-negative. 4.5% were resistant to tetracycline and most (86.6%) had MICs greater than or equal to 1 mg/L of erythromycin. Zone diameters around ampicillin discs were greater than or equal to 10 mm smaller than those around amoxycillin-clavulanate discs for 241 (79%) of M. catarrhalis. Although only 193/241 had been reported to be beta-lactamase positive by participating laboratories, data obtained at the coordinating centre confirmed that greater than or equal to 10 mm and less than or equal to 3 mm zone size differences correlated with beta-lactamase-positive and -negative isolates respectively. No M. catarrhalis were resistant to amoxycillin-clavulanate and less than 4% were resistant to either tetracycline or erythromycin. The prevalence of resistance to cefaclor was highest among H. influenzae (5.2%) and lowest among S. pneumoniae (0.9%). Only seven of 2008 isolates (two to three per species) were resistant to cefixime. The data suggest that the prevalence of resistance to ampicillin, tetracycline and erythromycin must be taken into consideration when treating respiratory infections.

Comparison of results from five serologic methods used for detecting Brucella abortus antibody activity in coyote sera

A total of 423 serum samples representing 94 coyotes which were wild trapped in east Texas were used to compare the serologic results from five different methods for detecting antibodies to Brucella abortus. The sera were tested for Brucella spp. antibody activity by the Card (CARD), rivanol precipitation (RIV), standard agglutination tube (SAT), cold complement fixation test (CF), and enzyme linked immunosorbent assay (ELISA) methods. Each serum sample selected for this comparison demonstrated antibody activity by one or more of the five serologic methods. When the serologic results of the five different methods were compared, 143 sera were positive according to the CF test and agreement was 67.1-70.6% with CARD, RIV and SAT. The maximum agreement for CF positive was with CARD (70.6%) and the lowest agreement fro CF negative was also with CARD (56.4%). Agreement among the serologic methods for the SAT positive ranged from 69.1% (CARD) to 72.7% (RIV). Agreement between SAT and ELISA was poor with only 38.1% agreement for SAT positive and 11.3% agreement for SAT negative. Agreement between methods for CARD positive sera was poor, with a low of 43% for both SAT and ELISA, and a high of 55.6% for RIV. Agreement between methods for 149 RIV positive sera was 83.2% for CARD, 67.8% for SAT, 64.4% for CF and only 50.3% for ELISA. Agreement between methods for ELISA positive results ranged from 49.0% for RIV to 62.7% for CARD.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of injectable anesthetic combinations in horses

Six combinations of injectable anesthetic agents were administered to six adult horses in a Latin square design. The drug combinations were xylazine-ketamine, xylazine-butorphanol-ketamine, xylazine-tiletamine-zolazepam, xylazine-butorphanol-tiletamine-zolazepam, detomidine-ketamine, and detomidine-butorphanol-ketamine. Measured variables were heart rate, respiratory rate, systolic blood pressure, arterial pH (pHa), PaCO2, PaO2, recumbency time, and number of attempts necessary to stand. Quality of induction and recovery, muscle relaxation, and response to stimulus were evaluated subjectively. The horses required significantly more attempts to stand after administration of xylazine-tiletamine-zolazepam, xylazine-butorphanol-tiletamine-zolazepam, and detomidine-ketamine than after xylazine-ketamine, xylazine-butorphanol-ketamine, or detomidine-butorphanol-ketamine. Mean recumbency times varied from 23.0 minutes with xylazine-ketamine to 41.3 minutes with xylazine-butorphanol-tiletamine-zolazepam. There were significant differences in mean heart rates at minute 15, mean respiratory rates at minutes 5, 10 and 15, and mean systolic blood pressures at minute 10 of anesthesia. There were no significant differences in pHa, PaCO2 or PaO2.

Enalapril can treat the proteinuria of membranous glomerulonephritis without detriment to systemic or renal hemodynamics

The effect of enalapril on renal hemodynamics and glomerular permselectivity was studied in eight patients with nephrotic syndrome secondary to biopsy-proven membranous glomerulonephritis. The patients received the drug in incremental doses (median, 5 mg) until 24-hour urinary protein excretion had decreased persistently by 30%. Median treatment duration was 6 weeks. Patients were studied three times: (I) after a 4-week run-in period, (II) on the final day of treatment, and (III) after a 4-week wash-out. Median 24-hour urinary protein excretion decreased on treatment from 10.45 g/d to 5.25 g/d and increased to pretreatment levels after the drug was stopped (P less than 0.05 for both changes). Fractional clearance of dextrans greater than 4.1 nm decreased on treatment, indicating both a reduction of macromolecules passing through the shunt pathway of the glomerular basement membrane (GBM) and a possible decrease in ultrafiltration coefficient. There were no significant changes in glomerular filtration rate (GFR), effective renal plasma flow (ERPF), or mean arterial blood pressure (MAP) throughout the study. The effect of enalapril in treating proteinuria appears therefore to be due to a specific intraglomerular action.

Characterisation and distribution of epidermal growth factor receptors in equine hoof wall laminar tissue: comparison of normal horses and horses affected with chronic laminitis

Epidermal growth factor (EGF) receptors were detected in plasma membrane preparations of equine hoof wall laminar tissue at concentrations comparable to that of equine liver. Scatchard analysis of the equilibrium binding data suggested the presence of two classes of EGF binding sites in most of the controls (plasma membranes from clinically normal horses); a high-affinity class and a more numerous low-affinity class. The dissociation constant of the low-affinity class of EGF-specific receptors (KD = 1 x 10(-9)M) is in reasonable agreement with other values established for the EGF receptor. The variability between individual estimates for the KD of the high-affinity receptor class precluded an accurate estimate for those sites. A possible explanation is discussed. The high-affinity binding sites were uniformly absent in plasma membranes prepared from horses affected by chronic laminitis. Autoradiographic analysis localised the EGF receptors primarily to the secondary epidermal laminae, with an apparent greater density over the proliferative basal keratinocytes. Little label was associated with the dermal or the keratinised primary epidermal laminae. Tissue from horses with chronic laminitis had EGF receptors located uniformly over the hyperplastic epidermal keratinocytes. These data suggest that an EGF-mediated response may be involved in the hyperproliferative response that is characteristic of chronic laminitis.