Effects of prenatal and postnatal melatonin supplementation on overall performance, male reproductive performance, and testicular hemodynamics in beef cattle

Melatonin has been documented to alleviate compromised pregnancies and enhance livestock performance traits. The objective of this study was to determine the effect of prenatal and postnatal melatonin supplementation on overall calf performance and dam milking traits in relation to calves, molecular factors involved in growth and metabolism of calves, along with testicular physiology and fertility traits in subsequent bulls. On days 190, 220 and 250 of gestation, dams (N = 60) were administered either two subdermal ear melatonin implants (preMEL) or no implants (preCON). After parturition, birth weights were recorded and calves were blocked based on prenatal treatment and sex. Calves received either melatonin implants (posMEL) or none (posCON) on days 0, 30, and 60 of age. On day 60 of lactation, a subset of dams (N = 32) were selected based on age, weight, and calf sex for milk collection and analysis. At weaning, (day 210 postnatally) calf weight, morphometric data, liver samples, and loin samples were collected. At 12 mo of age, bull (N = 30) scrotal circumference, scrotal temperature, and testicular artery measurements were recorded. Milk yield and fat percent from dams tended to decrease in the preMEL group (P < 0.07) compared with preCON group. Prenatal melatonin administration did not affect (P = 0.95) calf birth weight and similarly calf weaning weight was unaffected (P < 0.10) by prenatal or postnatal melatonin supplementation. Blood analysis demonstrated that plasma concentrations of melatonin were not different (P = 0.12) in dams; however, an increase (P < 0.001) in plasma concentrations of melatonin was observed in posMEL vs. posCON calves. A tendency (P < 0.10) for decreased MYF5 and MYOD1 expression in loin muscle was observed in the posMEL calves. Prenatal and postnatal melatonin administration did not affect subsequent bull scrotal measurements or testicular hemodynamics (P ≥ 0.14). Administering supplemental melatonin via implants during the prenatal and postnatal phase did not alter performance characteristics in offspring. In this study, dams were implanted in winter months, whereas calves were implanted in the spring months. Seasonal differences involving photoperiod and ambient temperature might have attributed to a lack of differences in melatonin levels during the prenatal phase. In the postnatal period, the level of developmental plasticity appears to be too low for melatonin properties to be effective.

Differences in bovine placentome blood vessel density and transcriptomics in a mid to late-gestating maternal nutrient restriction model

INTRODUCTION

Prenatal development is reliant on a functioning placenta, which can be influenced by maternal nutrition. Moreover, the variation in cotyledonary capacity within an animal has not been fully examined to date. Therefore, the purpose of this study was to determine the effect of (1) placentome size and (2) maternal nutrient restriction on molecular, microscopic, and macroscopic features of bovine placentomes during late gestation.

METHODS

Pregnant cows (n = 6) were placed into one of 2 treatments: CON (100% NRC) vs RES (60% of NRC) from day 140 until slaughter at day 240 of gestation. Placentomes of various sizes were perfused to assess macroscopic blood vessel density of the cotyledon. Microscopic imaging and RNA extraction for sequencing was performed.

RESULTS

Macroscopic blood vessel density relative to placentome weight was not different (P = 0.42) among small, medium, or large placentomes. Cotyledonary microscopic blood vessel number, area, and perimeter was increased (P < 0.005) in high versus low blood perfusion areas. Differential expressed gene (DEG) analysis showed 209 upregulations and 168 downregulations in the RES group (P ≤ 0.0001). Gene Ontology (GO) analysis showed that downregulated enriched terms were involved in blood vessel and mesenchymal stem cells development, whereas upregulated enriched terms were involved with translation and ribosomal function.

DISCUSSION

This study demonstrates that placentome function is uniform across various placentome sizes within an animal. However, microscopic heterogeneity exists within each placentome. Maternal nutrient constraints alter placental transcriptomics which may yield compensatory mechanisms involved in nutrient transport including increased perimeter.

PSIII-26 The effects of maternal melatonin supplementation during pregnancy on longissimus dorsi muscle morphometrics in bovine fetuses at 240 days of gestation

Melatonin is a multifunctional hormone that positively impacts postnatal growth and weaning weight in cattle offspring when supplemented to adequately fed dams during gestation. However, it is unclear whether supplemental melatonin is effective as a countermeasure to decrease effects of a nutritionally compromised pregnancy on fetal tissues. The current study evaluated the efficacy of maternal melatonin supplementation during gestation, as a therapeutic in nutrient restricted beef heifers using fetal LM morphometrics for evaluation of carcass tissue growth. On gestational d 160, 25 Brangus heifers were assigned to one of four groups in a 2 x 2 factorial: nutrient restricted (RES-CON: 60% NRC; n = 6), adequate fed (ADQ-CON; 100% NRC; n = 6), nutrient restricted supplemented with 20 mg melatonin (RES-MEL; n = 7), or adequate fed supplemented with 20 mg melatonin (ADQ-MEL; n = 6). Treatments were top-dressed with 2 mL of melatonin dissolved in 100% ethanol (10 mg/mL) or 2 mL of ethanol (control). At gestational d 240, Caesarean sections and fetal necropsies were performed, both fetal LM were dissected to determine weight, length, and midline circumference. Data were analyzed using the MIXED procedure of SAS. There was a diet by treatment interaction wherein the mass of the left and right LM was increased (P0.035) by an average of 42.46 g in RES-MEL offspring compared to RES-CON fetuses, but no differences (P0.0812) among ADQ groups. Restricted nutrition decreased left LM circumference (10.21 vs. 10.95 cm; P = 0.0445). Treatment had no effect on LM length (P0.1139). In the present study, maternal melatonin supplementation during the Summer promoted muscle growth and mitigated the adverse effects of a nutritionally compromised pregnancy on LM morphometrics. These data are indicative of the potential for melatonin as a gestational therapeutic for prenatal muscle growth and improved efficiency of meat animal production.

The Effect of Melatonin Supplementation on Dam Milking Traits and Calf Performance in Beef Cattle

Melatonin has been documented to alleviate compromised pregnancies and enhance livestock performance traits. The objective of this study was to determine the effect of melatonin supplementation on milking traits in beef cattle dams and subsequent influence on calf performance. Cows (n = 60) were blocked based on embryo transfer donor and sire, potential calf breed and embryo grade. At d190, 220 and 250 of gestation, dams were administered either 2 subdermal ear melatonin implants (preMEL) or no implants (preCON). After parturition, birth weights were recorded and calves randomly received either melatonin implants (posMEL) or none (posCON) on approximately d 0, 30, and 60. At approximately d 60 of lactation, a subset of dams (n = 32) were selected based on age, weight and calf sex for milk collection and analysis. At weaning, calf weight and morphometric data were collected and adjusted according to weaning age. Prenatal melatonin administration did not change calf birth weight (P = 0.956). Milk yield tended to decrease in the preMEL group (P = 0.054) at 2.368 kg ± 0.11 compared to preCON at 2.054 kg ± 0.11. Milk fat percent tended to decrease (P = 0.07) in preMEL at 3.25 ± 0.19 versus preCON at 3.92 ± 0.19. There were no differences in prenatal treatment in respect to milk protein, lactose, solid non-fats, somatic cell count, and urea nitrogen (P &gt; 0.16). At weaning, calf head circumference decreased (P &lt; 0.031) in the preMEL group at 77.92cm ± 0.42 versus preCON at 79.31cm ± 0.45. Otherwise, there were no prenatal or postnatal treatment differences in respect to weaning weight, crown-rump length, hip height and head length (P &gt; 0.12). Previous studies show crown-to-rump length and ponderal index differences. Our lack of differences might be attributed to geographical locations that impact day length or endogenous melatonin status.

Effect of Diet and Location Within the Longissimus Dorsi Muscle on the Quality and Fat Composition of Pork Loins Collected from Market Hog

In pigs, the longissimus muscle (LM) is an economically important tissue that largely dictates the quality grade assigned to the carcass. Still, this anatomically protracted muscle is not homogeneous in composition and these spatial differences across the LM can impact the overall predicted quality and quantity of pork produced. The objective of this study was to determine the impact of diet and location within the muscle on the quality and fatty acid composition of loins harvested from finishing pigs. A total of 80 pigs were subjected to 1 of 4 dietary treatments: lysine deficient diet (LysDef), vitamin A deficient diet (VitADef), lysine and vitamin A deficient diet (LysVitADef), and control diet (CON) formulated to meet NRC recommended requirements from weaning through finishing. The animals were then harvested to assess LM quality parameters including loin eye area, marbling score, and lean color. Samples from the proximal, medial, and distal portions of the LM were collected for fatty acid determination using gas chromatography and were expressed as a percentage of total fatty acids. Marbling score was greatest (P = 0.0024) in the proximal LM and was not impacted by treatment (P = 0.07). Treatment also had no effect (P = 0.14) on the percentage of saturated fatty acids (SFA); however, the percentage of SFA decreased (P &lt; 0.001) from the proximal (40.9 ± 0.24) to distal (39.14 ± 0.24) portion. In contrast, the percentage of polyunsaturated fatty acids increased (P &lt; 0.001) from the proximal (15.96 ± 0.57) to distal (19.27 ± 0.57) portion. Despite the lack of diet-induced differences in marbling scores, the biological data generated from the current study are informative in terms of the spatial and compositional marbling deposition patterns in the LM of the growing pigs and warrant further investigation to identify the mechanisms responsible for this paradigm.

Labetalol infusion in acute myocardial infarction with systemic hypertension

1 Fifteen patients with suspected acute myocardial infarction and systemic BP of greater than 160/110 mmHg were treated with an incremental infusion of labetalol. 2 Systemic BPs were safely and effectively lowered to less than 130 mm Hg systolic or 90 mmHg diastolic in all pateints. 3 Heart rate, mean pulmonary artery wedge pressure cardiac index and stroke work index were significantly reduced. 4 The dose of labetalol varied from 30 mg-440 mg and was significantly higher (mean 295 mg) in those patients with pre-existing systemic hypertension compared with others (mean 133 mg). 5 No side- effects occurred and all patients survived to leave hospital.

Community HIV testing for men who have sex with men: results of a pilot project and comparison of service users with those testing in genitourinary medicine clinics

Results of a community HIV testing pilot (fasTest) targeting men who have sex with men (MSM) in Brighton are reported and service users are compared with those testing in genitourinary medicine (GUM) clinics. FasTest offers rapid HIV testing in a weekly evening drop-in session staffed by GUM professionals in a community organisation. It was prospectively evaluated from November 2004 to March 2006 using a self-completed paper questionnaire assessing demographics, previous use of GUM, HIV testing history and sexual behaviour. Follow-up through GUM/HIV services was monitored. A simplified questionnaire was completed by MSM accessing the GUM clinic over the same time period. Men were included in the analysis if they identified as gay or bisexual or had recent sex with a man, tested for HIV and received a result. In both the fastest and GUM groups, men reported high rates of unprotected anal sex in the last 3 months. fasTest clients were significantly younger and less likely to test positive for HIV. This difference was independent of age and HIV testing history. There was no difference in rates of recent infection between the two. We conclude that community HIV testing is feasible and reaches the target group of high risk MSM.

Technician run open access exercise electrocardiography

OBJECTIVE

To evaluate the safety, efficacy, and feasibility of the technician run open access exercise electrocardiography service at Freeman Hospital.

DESIGN

Questionnaire analysis of the responses of the general practitioners of randomly selected patients who used the service.

SETTING

A tertiary care cardiac centre, providing an open access service to general practitioners in the community.

PATIENTS

269 patients randomly selected from 552 who underwent open access exercise electrocardiography over a 2.5 year period.

OUTCOME MEASURES

Utilisation of service: the reasons for referral, whether the service was optimally used by the general practitioners, and its effect on their management practice; effect on number of cardiology referrals; benefit to the patients; safety, efficacy, and feasibility of a technician run service; general practitioners' assessment of the service.

RESULTS

147 of 178 general practitioners (82.6%) responded to the questionnaire, on 247 of 269 patients (91. 8%). General practitioners used the service for diagnosing ischaemic heart disease in 72.5% of cases, for prognostic purposes in 17.8%, or both in 5.3%. In 197 cases (79.8%), the general practitioners felt that the service had changed the way they managed their patients. The exercise test was positive in 90 patients (36.5%) and identified 38 as at high risk. The service was effective in optimising the cardiology service by reducing referrals by 47%.

CONCLUSIONS

The service was used by general practitioners primarily for diagnosing ischaemic heart disease and not so often for prognosis. The utilisation of the service was optimal as assessed by the high positivity rate. The service meets its primary objective of assisting general practitioners in the management of patients with suspected ischaemic heart disease, and may have helped to optimise resources by reducing the number of referrals to cardiologists. It has helped prioritize patient management and may have benefited high risk patients by facilitating rapid identification and referral. It can be run safely and effectively by trained technicians.

Microorganisms and microbial toxins

The primary concern in food safety issues focuses on microorganisms and microbial toxins. Effective food preservation requires that the growth and proliferation of hazardous microorganisms be well controlled, and that the presence of significant quantities of microbial toxins in foods be prevented. The traditional effective preservation methodologies, such as canning, are being supplemented by new technologies which are less destructive of the food qualities. New strategies are therefore needed to prevent the transmission of microbial contamination or to prevent the formation of microbial toxins which remain in food. This paper discusses the role of modern processing methodologies in helping protect consumers from hazards of microbial origin.

Telemedicine in Nova Scotia: report of a pilot study

OBJECTIVE

To provide and evaluate telemedicine services for rural physicians and patients in Nova Scotia.

MATERIALS AND METHODS

As a pilot project, three telemedicine services (videoconference continuing medical education [CME], teledermatology, and teleradiology) were provided to four hospitals in Nova Scotia communities. All four sites received CME (a total of 269 physicians, 53 other health care professionals); three sites received teledermatology (66 consultations), and two sites received teleradiology (808 radiologic examinations). At the consulting site, 12 faculty members presented 24 one-hour videoconferences, and there was one consulting radiologist and dermatologist. Each service was evaluated independently. Methods included participant questionnaires; focus groups; numbers and categories of participants or examinations; comparison of operational costs, capitol costs (teledermatology and teleradiology), and travel costs (CME); technical assessments of hardware, software, and telecommunications; assessment of clinical diagnostic procedures (teledermatology); and comparative study of original and digitized films (teleradiology).

RESULTS

Despite growing pains, the technologies effectively provided the three services: the services were acceptable to referring and consulting physicians and patients. Improvements in patient care and outcomes comparable to those of traditional methods were demonstrated in teleradiology and teledermatology, especially for emergencies. Physician access to CME and patient access to dermatology consultation services were improved. Financial savings were demonstrated for CME, but further investigation is required to determine the savings attributable to teleradiology and teledermatology.

CONCLUSIONS

The telemedicine services supported rural physicians, their patients, and their communities. Although telemedicine is not a panacea for all concerns of rural physicians, the pilot project provided a strong foundation for further development and study.

Sexual HIV risk behaviour among men who have sex with both men and women

The aim of this study was to describe the sexual behaviour of men who had sex with both men and women in the preceding five years (behaviourally bisexual men), specifically to examine their needs in relation to HIV prevention. Anonymous telephone interviews were carried out with respondents recruited though advertisements in UK newspapers and magazines with (sexual) 'personal' or 'contact' sections. Data are reported from 745 respondents. Respondents report relatively high and approximately equal numbers of male and female sexual partners in the year preceding interview. There is a clear patterning of sexual activity by type of partner (regular or casual). A high proportion report anal intercourse with female and male partners. A third disclose their homosexual practices to regular female partners. Although self-reported HIV seroprevalence is low (less than 1%), the levels of unprotected sex with multiple sexual partners indicate substantial potential for transmission of sexually transmitted infections, including HIV. While low seroprevalence suggests that there is little overlap with existing core groups of HIV infection, the study provides information to judge the priority of targeting HIV prevention initiatives and suggests ways in which initiatives could be undertaken.

Is trehalose special for preserving dry biomaterials?

Simple sugars, especially disaccharides, stabilize biomaterials of various composition during air-drying or freeze-drying. We and others have provided evidence that direct interaction, an interaction that we believe is essential for the stabilization, between the sugar and polar groups in, for example, proteins and phospholipids occurs in the dry state. Some researchers, however, have suggested that the ability of the sugar to form a glass is the only requirement for stabilization. More recently, we have shown that both glass formation and direct interaction of the sugar and headgroup are often required for stabilization. In the present study, we present a state diagram for trehalose glass and suggest that the efficacy of this sugar for stabilization may be related to its higher glass transition temperatures at all water contents. We also show that trehalose and trehalose:liposome preparations form trehalose dihydrate as well as trehalose glass when rehydrated with water vapor. Formation of the dihydrate sequesters water, which might otherwise participate in lowering the glass transition temperature to below ambient. Because samples remain in the glassy state at ambient temperatures, viscosity is high and fusion between liposomes is prevented.

No aggregate change in homosexual HIV risk behaviour among gay men attending the Gay Pride festivals, United Kingdom, 1993-1995

OBJECTIVES

To examine aggregate changes in homosexual HIV risk-taking among gay men attending the Gay Pride festival in the United Kingdom over a 3-year period during which HIV prevention activity targeted at this population increased considerably.

DESIGN

Three cross-sectional self-completion questionnaires at yearly intervals asking identical questions on sexual behaviour in the preceding year.

SETTING

Lesbian and Gay Pride festival held in London, June 1993, 1994 and 1995.

PARTICIPANTS

Men attending the festival who were UK resident, had ever had sex with another man and who were willing to fill out a questionnaire (n = 1620, 1753 and 1168 in 1993, 1994 and 1995, respectively).

MAIN OUTCOME MEASURES

Self-reported numbers of sexual partners, sexual partners with whom anopenile intercourse occurred and sexual partners with whom anopenile intercourse occurred without a condom.

RESULTS

Over the 3-year period there were no changes in the proportion of men engaging in any of the sexual behaviour measures. At each cross-section, one in three men (514 out of 1566, 511 out of 1612, 351 out of 1059 in 1993, 1994 and 1995, respectively) had engaged in anopenile intercourse without a condom with at least one male partner in the preceding year and one in 10 (162 out of 1566, 156 out of 1612, 103 out of 1059 in 1993, 1994 and 1995, respectively) had done so with more than one male partner.

CONCLUSION

Despite an increase in prevention work targeted at this population, aggregate levels of sexual risk-taking have remained very stable. A reassessment of the efficacy of current HIV prevention messages and methods with this population is urgently required.

Self-renewal of primitive human hematopoietic cells (long-term-culture-initiating cells) in vitro and their expansion in defined medium

A major goal of experimental and clinical hematology is the identification of mechanisms and conditions that support the expansion of transplantable hematopoietic stem cells. In normal marrow, such cells appear to be identical to (or represent a subset of) a population referred to as long-term-culture-initiating cells (LTC-ICs) so-named because of their ability to produce colony-forming cell (CFC) progeny for > or = 5 weeks when cocultured with stromal fibroblasts. Some expansion of LTC-ICs in vitro has recently been described, but identification of the factors required and whether LTC-IC self-renewal divisions are involved have remained unresolved issues. To address these issues, we examined the maintenance and/or generation of LTC-ICs from single CD34+ CD38- cells cultured for variable periods under different culture conditions. Analysis of the progeny obtained from cultures containing a feeder layer of murine fibroblasts engineered to produce steel factor, interleukin (IL)-3, and granulocyte colony-stimulating factor showed that approximately 20% of the input LTC-ICs (representing approximately 2% of the original CD34+ CD38- cells) executed self-renewal divisions within a 6-week period. Incubation of the same CD34+ CD38- starting populations as single cells in a defined (serum free) liquid medium supplemented with Flt-3 ligand, steel factor, IL-3, IL-6, granulocyte colony-stimulating factor, and nerve growth factor resulted in the proliferation of initial cells to produce clones of from 4 to 1000 cells within 10 days, approximately 40% of which included > or = 1 LTC-IC. In contrast, in similar cultures containing methylcellulose, input LTC-ICs appeared to persist but not divide. Overall the LTC-IC expansion in the liquid cultures was 30-fold in the first 10 days and 50-fold by the end of another 1-3 weeks. Documentation of human LTC-IC self-renewal in vitro and identification of defined conditions that permit their extensive and rapid amplification should facilitate analysis of the molecular mechanisms underlying these processes and their exploitation for a variety of therapeutic applications.

Rescue thrombolysis: alteplase as adjuvant treatment after streptokinase in acute myocardial infarction

BACKGROUND

In acute myocardial infarction patients who do not reperfuse their infarct arteries shortly after thrombolytic treatment have a high morbidity and mortality. Management of this high risk group remains problematic, especially in centres without access to interventional cardiology. Additional thrombolytic treatment may result in reperfusion and improved left ventricular function.

METHODS

Failure of reperfusion was assessed non-invasively as less than 25% reduction of ST elevation in the electrocardiographic lead with maximum ST shift on a pretreatment electrocardiogram. 37 patients with acute myocardial infarction who showed electrocardiographic evidence of failed reperfusion 30 minutes after 1.5 MU streptokinase over 60 minutes were randomly allocated to receive either alteplase (tissue type plasminogen activator (rt-PA) 100 mg over three hours) (19 patients) or placebo (18 patients). 43 patients with electrocardiographic evidence of reperfusion after streptokinase acted as controls. Outcome was assessed from the Selvester Q wave score of a predischarge electrocardiogram and a nuclear gated scan for left ventricular ejection fraction 4-6 weeks after discharge.

RESULTS

Among patients in whom ST segment elevation was not reduced after streptokinase, alteplase treatment resulted in a significantly smaller electrocardiographic infarct size (14% (8%) v 20% (9%), P = 0.03) and improved left ventricular ejection fraction (44 (10%) v 34% (16%), P = 0.04) compared with placebo. This benefit was confined to patients who failed fibrinogenolysis after streptokinase (fibrinogen > 1 g/l). In patients in whom ST segment elevation was reduced after streptokinase, infarct size and left ventricular ejection fraction were not significantly different from those in patients treated with additional alteplase.

CONCLUSION

Patients without electrocardiographic evidence of reperfusion after streptokinase may benefit from further thrombolysis with alteplase.

Determinants of the length of stay in intensive care and in hospital after coronary artery surgery

BACKGROUND

Patients who have coronary artery surgery normally occupy intensive care beds for less than 24 hours. Longer stays may result in under use of cardiac surgical capacity. One approach to optimise surgical throughput is prospectively to identify fast track patients--that is, those who occupy an intensive care bed for less than 24 hours. A prospective audit of patients was performed to identify fast track patients by simple clinical criteria. Total length of hospital stay was also assessed in an attempt to predict which patients were likely to have a short postoperative stay, defined as < or = 7 days.

METHODS

Baseline demographic details, cardiovascular risk factors, angiographic and operative details were recorded for 431 consecutive patients who underwent coronary surgery at a regional centre over a nine month period. Outcome measures were the duration of the stay in the intensive care unit in hours and total duration of the postoperative stay in hospital in days. In addition, two groups of patients who were thought to be fast track were identified prospectively. Fast track 1 patients were identified by criteria selected by cardiovascular physicians. These were age less than 60 years, stable angina, good left ventricular function (ejection fraction > 50%), good renal function (serum creatinine < 120 mumol/l), and no obesity, diabetes, or other serious disease. Fast track 2 patients were identified by criteria defined by cardiovascular surgeons. These were male sex, age less than 65 years, good left ventricular function and no peripheral vascular disease, diabetes, or other serious disease. The efficacy of both sets of criteria in predicting outcome was tested.

RESULTS

344 (79.8%) patients were fast track. Significant factors for the prediction of fast track patients by univariate analysis (with positive predictive accuracy and sensitivity) were left ventricular ejection fraction > 50% (83%, 80%), left ventricular end diastolic pressure < 13 mm Hg (90%, 59%), creatinine less than 120 mumol/l (83%, 87%), and one or two vessel coronary disease (89%, 34%). Of the patients categorised as fast track 1 89% proved to be fast track (sensitivity 24%), however, the fast track 2 characteristics were not significant. Age, sex, obesity, diabetes, hypertension, a history of obstructive pulmonary disease and unstable angina were not predictive of the duration of intensive care stay. Multivariate analysis indicated that only left ventricular end diastolic pressure and the number of diseased coronary arteries predicted fast track patients. These criteria separated patients into three groups. Those who were good risk had one or two vessel disease and left ventricular end diastolic pressure < 13 mm Hg. They comprised 19% of the total and 93% of them were fast track. Those who were intermediate risk had either three vessel disease or left ventricular end diastolic pressure > 13 mm Hg but not both. They comprised 49% of the total and 85% of them were fast track. Those who were poor risk had both three vessel disease and left ventricular end diastolic pressure > 13 mm Hg. They comprised 32% of the total and 62% of them were fast track. The 106 (24%) patients who spent < or = 7 days in hospital after surgery were significantly younger (mean (SD) 55(8) v 58(8) years; P < 0.001) with a lower incidence of previous myocardial infarction (positive predictive accuracy 30%, sensitivity 53%), were less likely to have a history of obstructive pulmonary disease (25%, 98%), and more likely to have one or two vessel coronary disease (33%, 41%). They were more likely to have an internal mammary artery as a bypass conduit (27%, 89%) and more likely to need fewer than three distal anastomoses of the vein graft (29%, 63%). By multivariate analysis only age was significantly predictive of hospital stay. Total hospital stay could not be satisfactorily modelled on the basis of the criteria tested here. Sex, obesity, diabetes, hypertension, unstable angina, renal function, and left ventricular function were not associated with hospital stay. CONCLUSIONS-Most patients who had coronary artery surgery spent less than or equal to 24 hours in intensive care, but most spent > 7 days in hospital. The chance of a patient spending less than or equal to 24 hours in intensive care could be predicted by the number of coronary arteries diseased and the left ventricular end diastolic pressure. Poor risks patients (32%) had only a 62% chance of an intensive care unit stay of less than or equal to 24 hours. A policy of scheduling no more than one such patient for surgery per day would be simple to institute and would maximise the use of surgical capacity.

Differential expression of homeobox genes in functionally distinct CD34+ subpopulations of human bone marrow cells

Class I homeobox (Hox) genes encode a major group of transcription factors controlling embryonic development and have been implicated in the continuing process of hematopoietic cell differentiation. They are clustered on four chromosomes and, in early development, exhibit spatially restricted expression with respect to their 3'-->5' chromosomal position. By using an improved PCR-based method for amplifying total cDNA derived from limited cell numbers, we now describe the expression of class I Hox genes in highly purified CD34+ cell subpopulations isolated from normal human bone marrow that represent functionally distinct stem and progenitor cell compartments. Our data indicate that at least 16 different Hox genes, mainly from the A and the B clusters, are expressed in one or more of these subpopulations of human hematopoietic cells. Moreover, markedly elevated expression of some of the Hox genes found at the 3' end of the A and B clusters (e.g., HoxB3) was a unique feature of the subpopulations that contained the most primitive functionally defined cells, whereas genes located in the 5' region of each cluster (e.g., HoxA10) were found to be expressed at nearly equal levels in the CD34+ subpopulations analyzed. In contrast to the findings for CD34+ cells, expression of two selected Hox genes, HoxB3 and HoxA10, was virtually extinguished in the CD34- fraction of bone marrow cells. These results demonstrate the expression of a broad range of Hox genes in primitive hematopoietic cells and point to the existence of a regulated program of Hox gene expression during their normal development.

Pericardial effusion--an uncommon complication of Salmonella enteritis

A 62-year-old lady who was receiving corticosteroids for rheumatoid arthritis was admitted suffering from dehydration due to salmonella enteritis. Despite rehydration and appropriate chemotherapy she remained unwell and developed hypotension and elevation of her jugular venous pressure. Echocardiography and subsequent aspiration demonstrated a purulent pericardial effusion from which S typhimurium was cultured. Following aspiration and a change of antibiotic therapy, her condition improved dramatically.

Delays to thrombolysis in the treatment of myocardial infarction

In-hospital delays to thrombolysis were significantly shorter when thrombolysis was available on admission to the accident and emergency department than after transfer to the coronary care unit (median 60 min v 84 min, p < 0.0001). With direct admission by general practitioners to a coronary care unit the subsequent in-hospital delay was shorter (median 39 min p = 0.0004), but overall delay to thrombolysis longer (median 220 v 170 min, p = 0.0019) because of longer pre-hospital delays. Overall delay was shortest with emergency ambulance referral and thrombolysis being administered in the accident and emergency department.

Characterization of primitive hematopoietic cells in normal human peripheral blood

The total number of clonogenic cells present in 5-week-old long-term cultures (LTC) initiated by seeding normal human marrow cells on competent adherent cell feeder layers allows for the quantitation of a more primitive hematopoietic input precursor cell type referred to as an LTC-initiating cell (LTC-IC). Previous studies have suggested that LTC-IC also circulate because production of clonogenic cells continues for many weeks when cells from the light-density (< 1.077 g/mL), T-cell-depleted fraction of normal blood are maintained on irradiated, marrow-derived feeder layers in LTC medium. We now show that the number of clonogenic cells present in such reconstructed LTC after 5 weeks is linearly related to the input number of peripheral blood (PB) cells over a wide range of cell concentrations, thereby permitting the quantitation of circulating LTC-IC by limiting dilution analysis. Using this approach, we have found the concentration of LTC-IC in the circulation of normal adults to be 2.9 +/- 0.5/mL. This is approximately 75-fold lower than the concentration of circulating clonogenic cells (ie, burst-forming units-erythroid plus colony-forming units [CFU] granulocyte-macrophage plus CFU-granulocyte, erythroid, monocyte, megakaryocyte) and represents a frequency of LTC-IC relative to all nucleated cells that is approximately 100-fold lower than that measured in normal marrow aspirate samples. Characterization studies showed most circulating LTC-IC to be small (low forward light scatter and side scatter), CD34+, Rh-123dull, HLA-DR-, and 4-hydroperoxycyclophosphamide-resistant cells, with differentiative and proliferative potentialities indistinguishable from LTC-IC in normal marrow. Isolation of the light-density, T-cell-depleted, CD34+, and either HLA-DR(low) or Rh-123(dull) fraction of normal blood yielded a highly enriched population of cells that were 0.5% to 1% LTC-IC (approximately 1,500-fold enriched beyond the light-density, T-cell-depletion step), a purity comparable to the most enriched populations of human marrow LTC-IC reported to date. However, purification of PB LTC-IC on the basis of these properties did not allow them to be physically separated from a substantial proportion (> 30%) of the clonogenic cells in the same samples, in contrast to previous findings for LTC-IC and clonogenic cells in marrow. These studies show the presence in the blood of normal adults of a relatively small but readily detectable population of functionally defined, primitive hematopoietic cells that share properties with marrow LTC-IC, a cell type thought to have in vivo reconstituting potential.(ABSTRACT TRUNCATED AT 400 WORDS)

Rapid decline of chronic myeloid leukemic cells in long-term culture due to a defect at the leukemic stem cell level

In this report we describe a quantitative in vitro assay for the most primitive type of leukemic precursors yet defined in patients with chronic myeloid leukemia (CML). This assay is based on the recently described "long-term culture-initiating cell" (LTC-IC) assay for primitive normal human hematopoietic cells. Such cells, when cocultured with competent fibroblast feeder layers, give rise after a minimum of 5 weeks to multiple single and multilineage clonogenic progenitors detectable in secondary semisolid assay cultures. Similar cultures initiated by seeding a highly enriched source of leukemic cells from patients onto normal feeders showed the clonogenic cell output after 5 weeks to be linearly related to the input innoculum over a wide range down to limiting numbers of input cells, thus allowing absolute frequencies of leukemic LTC-ICs to be determined using standard limiting dilution analysis techniques. Leukemic LTC-IC concentrations in CML marrow were found to be decreased, on average to less than 10% of the normal LTC-IC concentration in normal marrow, but were greatly increased (up to greater than 10(5) times) in CML blood. Assessment of the number of clonogenic cells produced per leukemic LTC-IC by comparison to normal blood or marrow LTC-IC values showed this function to be unchanged in leukemic LTC-ICs [i.e., 3.1 +/- 0.4 clonogenic cells per CML LTC-IC (mean +/- SEM, n = 6) versus 3.7 +/- 1.2 (n = 3) and 4.3 +/- 0.4 (n = 5), respectively, for normal blood and marrow LTC-ICs]. In contrast, leukemic LTC-IC maintenance in LTC proved to be highly defective by comparison to normal LTC-IC of either blood or marrow origin. Thus, when cells from primary LTC were subcultured into secondary LTC-IC assays, leukemic LTC-IC rapidly declined (greater than 30-fold) within the first 10 days of culture, whereas normal LTC-IC numbers remained unchanged during this period. These findings illustrate how self-maintenance and differentiation events in primitive human hematopoietic cells can be differentially modulated by an oncogenic process and provide a framework for further studies of their manipulation, analysis, and therapeutic exploitation.

The occurrence of early sudden coronary artery occlusion following angioplasty may be predicted from the clinical characteristics of the patients and their coronary lesion morphology

The aim of this study was to assess whether the incidence of early occlusion following angioplasty was greater among patients with unstable angina and whether the coronary lesions prone to early occlusion could be predicted from their angiographic appearance. Seventy-seven patients who had had a first angioplasty of a native vessel for stable or unstable angina in one twelve month period were included. The angiographic appearances of the angioplastied lesions were classified as either Type 1, which were smooth and unlikely to have thrombus or intimal rupture, or Type 2, which were irregular due to thrombus or intimal rupture. The lesion classification was compared to the patients' clinical features, i.e. stable or unstable angina, and the outcome of the angioplasty. Type 2 lesions occurred in 25% of patients with stable angina but 49% of patients with unstable angina (p less than 0.05). Early sudden occlusion of the angioplastied vessel occurred in 24% of patients with unstable angina but in only 3% of patients with stable angina (p less than 0.05) and in 6% of Type 1 lesions compared with 24% of Type 2 lesions (p less than 0.05). Thus it is possible to identify the clinical characteristics and angiographic appearances of those patients undergoing angioplasty who are most likely to experience early vessel occlusion.

Incessant atrial tachycardia accelerated by pregnancy

A 24 year old patient presented with incessant atrial tachycardia during the course of a twin pregnancy. Medical treatment slowed the ventricular response without restoring sinus rhythm. During labour the tachycardia spontaneously reverted to sinus rhythm. Subsequently the same arrhythmia was documented with a slower ventricular response than during pregnancy.

Septal rupture after myocardial infarction: is very early surgery really worthwhile?

Despite numerous publications, mostly with small patient populations, the management of post-infarct septal rupture is still not well defined. Although urgent surgery appears to be the therapy of choice it is still unclear whether surgery very early after septal rupture in patients with severe haemodynamic compromise salvages a significant number of patients. In this paper we present the data from a large population of consecutive patients with post-infarct septal rupture from one cardiac centre. From 1980 through 1989, 108 patients with post-infarct septal rupture were seen at this Regional centre of whom 81 had operative repair; 43 (53%) of these survived the early postoperative period. Of 32 patients with cardiogenic shock who had surgery, early operative mortality in those operated on within 48 h of rupture was 90% (18/20) compared with 33% (4/12) in those operated on later (P less than 0.001). All survivors with pre-operative shock had intra-aortic balloon counter-pulsation before operation. Concomitant coronary artery bypass grafting was not associated with improved survival in our patients. Three patients survived long-term without operation. Analysis of population statistics suggest that approximately 270 patients with post-infarction septal rupture were not transferred from peripheral hospitals to the Regional Cardiothoracic Centre for assessment during this decade.

Melanoma metastatic to breast

A patient presented with an unusual case of a breast mass. History and meticulous physical examination led to the diagnosis of metastatic melanoma, which was confirmed by biopsy. The differential diagnosis of metastasis to breast is discussed.

Salmonella: a rare cause of subacute effusive-constrictive pericarditis

A 36 year old woman had emergency pericardectomy because of subacute effusive-constrictive pericarditis. The pericardial fluid and tissue culture showed that this was caused by infection with Salmonella enteritidis. Cardiac involvement with salmonella does not usually present in such an aggressive manner and it has not previously been reported to cause this rare type of cardiac constriction.

Effect of solute on the nucleation and propagation of ice

Using the emulsion technique, we have studied nucleation of ice in aqueous solutions containing silver iodide or Pseudomonas syringae. Using a Differential Scanning Calorimeter (DSC), we determined characteristic temperatures of nucleation, and also rates of nucleation at selected temperatures. The freezing point depression induced by added solute is linearly related to the lowering of both homogeneous and heterogeneous nucleation temperature. Nucleation kinetics depend on a fifth power function of the temperature. Solute is found to affect the parameters of this relationship in different ways, dependent upon the nature of the catalytic site for ice nucleation. We have also studied the effect of composition on the linear propagation velocity (LPV) of ice in undercooled solutions contained in a U-tube. We have determined velocities in a range of concentrations of sugar solution at the same undercooling, and also as a function of undercooling. The role of added polymer has also been investigated. It is affected by the sugar concentration.

Studies of reaction kinetics in relation to the Tg' of polymers in frozen model systems

The rates of diffusion-controlled processes in a frozen system can be influenced by the presence of glassy states. One characteristic of cryostabilization by this mechanism is a change in the temperature dependence of reaction rates at the Tg' of the system. The cryostabilization behavior of solutes such as maltodextrin, carboxymethylcellulose (CMC), and sucrose was studied. Three different model reaction systems (enzyme hydrolysis, protein aggregation, and non-enzymatic oxidation) were used. Maltodextrin had a consistent pattern of cryostabilization behavior at temperatures ranging from -3 degrees C to -20 degrees C for all three model systems. Significant retardation effects were evident in the temperature range corresponding to its glassy states. Sucrose did not show a stabilizing effect in the non-proteinaceous model system (the non-enzymatic oxidation reaction). This could partly be due to the absence of the glassy state, since the storage temperatures were above its Tg'. However, in the protein aggregation model system, sucrose was an excellent stabilizer in protecting actomyosin from aggregation. This may be explained by a "solute exclusion" mechanism. CMC did not show any stabilizing effect in the protein aggregation and non-enzymatic oxidation model systems studied, even though it has a Tg' as high as that of maltodextrin. These results demonstrated that although the presence of a glassy state may well have a retarding effect on the rates of diffusion processes, just knowing the Tg' of a polymer is not sufficient for prediction of its stabilization effect in a frozen system.

Ionic diffusion in frozen starch gels

Quality changes in food frozen by different conditions and at different storage temperatures were demonstrated using a model system. A frozen starch gel represents a frozen food matrix, and ions in the external medium represent the reactant molecules. We determined the effective diffusion rates of Zn+2 ions into frozen starch gel cylinders that were frozen at different freezing rates. The diffusion was performed at -8 degrees and -15 degrees C. The amounts of ion diffused were determined by atomic absorption, whilst the structure of the frozen samples could be simultaneously determined by scanning electron microscopy. The effective diffusion rates were found to correlate with the amount of unfrozen portion of the samples. This suggests that ions move mainly through the unfrozen portion around the ice crystals. Fast- and slow-frozen samples exhibited significantly different effective diffusion rates at -15 degrees C, which might be due to differences in size and orientation of ice crystals. Zn+2 ions moved slower at -15 degrees C than at -8 degrees C.

Phase volume measurements using magnetic resonance imaging

The phase distribution of components in both model and actual food systems has been quantified using Magnetic Resonance Imaging. We present measurements of effective moisture diffusivities, vertical mass distributions in foams, and crystallization of water and lipid components. The interpretation of this information allows one to quantify the interactions of various components and structural features within a sample. These measurements are made noninvasively and nondestructively and can be repeated over time to obtain information on the dynamics of the system.

Reduction in ST segment elevation after thrombolysis predicts either coronary reperfusion or preservation of left ventricular function

The usefulness of a reduction in ST segment elevation to predict coronary reperfusion in myocardial infarction remains uncertain. ST segment changes and angiographic findings were compared in 45 patients soon after thrombolysis. The percentage ST segment change 3 hours after treatment (in the lead showing the greatest initial ST elevation) was compared with the TIMI perfusion grade (thrombolysis in myocardial infarction trial) obtained between 90 minutes and 3 hours after treatment. Global ejection fraction and regional wall motion were assessed by cineventriculography (11 (5) days (mean (SD))) and by gated blood pool imaging (44 (11) days). Prediction of coronary patency by a reduction of greater than 25% in ST segment elevation 3 hours after thrombolytic treatment had a sensitivity of 97% but a specificity of only 43%. Where the ST segment elevation was reduced by greater than 25% the global ejection fraction was well maintained whether or not the infarct vessel was patent. In patients with a reduction of less than 25% in ST elevation, the ejection fraction was significantly lower and regional wall motion abnormality more severe. Reduction in ST elevation of greater than 25% within 3 hours of thrombolysis indicates either a patent infarct artery or preservation of left ventricular function. When the ST segment elevation does not fall by greater than 25% persistent coronary occlusion is likely (predictive accuracy 86%) and is associated with a lower ejection fraction. These patients may benefit from further treatment or additional interventions.

A simple, clinical assay to evaluate the acrosin activity of human spermatozoa

Acrosin, a sperm-specific acrosomal proteinase, has an essential role in the fertilization process. Low levels of acrosin appear to be associated with subfertility and infertility, and the acrosin activity of spermatozoa may potentially be a useful indicator of semen quality. The standard acrosin tests employed by research laboratories are too complicated and/or time consuming for clinical use; therefore, a simple assay has been developed to assess total acrosin activity (acrosin and activatable proacrosin). To perform the test, liquefied semen is centrifuged over Ficoll, the washed sperm pellet is suspended in a detergent (Triton X-100)-substrate (N-alpha-benzoyl-DL-arginine p-nitroanilide) buffer, pH. 8.0, and the amidase activity is determined spectrophotometrically after a 3-hour incubation period. Amidase activity can be inhibited with benzamidine, indicating that the activity is primarily or entirely due to acrosin. The absence of detergent in the incubation medium results in greatly reduced activity. The assay is repeatable, linear with increasing sperm concentration, sensitive to a lower limit of 2 x 10(6) spermatozoa, and the results correspond to those obtained with a standard acrosin extraction and assay technique. Storage of ejaculates at 3 to 6 C or at 22 to 24 C for 24 hours does not affect the acrosin activity significantly but much higher temperatures can cause a loss of activity. Freezing ejaculates results in a large decrease in sperm acrosin activity. Leukocytes show minimal activity in the assay. Sperm populations prepared by a swim-up procedure average approximately a 2-fold higher acrosin activity than the original ejaculates. Preliminary experiments indicate that the average sperm acrosin activity of ejaculates whose spermatozoa successfully fertilize human eggs in vitro is significantly higher than those that do not fertilize eggs.

Coupling of redox indicator dyes into an enzymatic reaction cycle

The spectral properties of ten redox indicator dyes were evaluated with the aim of finding the optimal choice for coupling to enzymatic reactions with high sensitivity for the production of the reduced form. Eight of the dyes were selected for coupling into a reaction cycle formed by yeast alcohol dehydrogenase with substrates ethanol and nicotinamide adenine dinucleotide (NAD+) and diaphorase with substrates reduced nicotinamide adenine dinucleotide (NADH, produced by the prior reaction) and the oxidized form of the respective dye. Two of the dyes exhibited decreased absorption on reduction, whereas all (eight) tetrazolium dyes increased in their absorption substantially upon reduction. Bis-tetrazolium dyes had a significantly higher molar extinction coefficient (up to 23,000 M-1.cm-1) than mono-tetrazolium dyes (down to 8000 M-1.cm-1). Kinetically, most dyes could be reduced with NADH (and diaphorase), but the rate of reduction varied considerably among the dyes with nitroblue tetrazolium (NBT) and tetranitroblue tetrazolium (TNBT) being the fastest. Therefore, NBT and TNBT seem to be the most suitable for fast response.

Gravitational and magnetic activation methods applied to cultured cells (LK 35.2)

Monoclonal antibody 10.2-16 is directed toward the mouse class II major histocompatibility complex gene product 1-Ak expressed on the cell line LK35.2. Instead of activating cells by fluorophor we used (acrylamide-coated) heavy and magnetic microspheres of 0.6 micron in radius. These microspheres are chemically coupled (carbodiimide method) with the antibody toward the surface antigen. The cells are observed through a microscope with horizontal alignment, as they sediment in a (temperature controlled) tube with square cross-section. Stokes Law allows the determination of the density of cells (first alone) using viscosity and density of Dulbecco's modified Eagle's Medium together with the observed mean sedimentation velocity (66 microns/min) and a mean diameter of 10 microns. We found a density of 1.0558 +/- 0.0028 g/cm3 at 10 degrees C. Independently, thinly coated, heavy (and magnetizable) microspheres with the cited antibody are attached to cells and observed likewise. The increased sedimentation velocity permits us to show that the cells were fully covered with microspheres (290 per cell). A magnetic field gradient opposing gravity moved these cells against gravity with two different mean velocities, 340 microns/min and 850 microns/min. The higher velocity resulted in 290 particles per cell, the lower one in 130 particles per cell. The limits for the expansion of this method to smaller particle sizes (down to 10 nm) are evaluated.

Prevention of tolerance to nitroglycerin patches by overnight removal

This investigation assesses the extent of tolerance development with nitroglycerin patches and whether tolerance might be prevented by overnight patch removal. On commencing therapy, active patches significantly prolonged exercise time (3.5 hours after patch application) in comparison with placebo, with an accompanying reduction in ST-segment depression at maximal common workload. Patients then received continuous or 12-hour-daily intermittent patch therapy, in a double-blind fashion, for 7 days. Exercise testing was repeated before and after active patch application, on the eighth day of each treatment phase. During continuous therapy, beneficial effects on exercise time and ST depression were abolished. By contrast, during intermittent therapy, prolongation of exercise time and reduction in ST-segment depression still occurred, on testing 3.5 hours after active patch application. These results confirm previous studies showing a high degree of tolerance during continuous therapy with nitroglycerin patches and suggest that tolerance can be prevented by 12-hour-daily intermittent therapy.

Effect of aryl 4-guanidinobenzoates on the acrosin activity of human spermatozoa

Certain aryl 4-guanidinobenzoates (AGs; inhibitors of proteinases, including the sperm enzyme acrosin) have been shown to be more potent vaginal contraceptives in rabbits and less toxic than nonoxynol-9, the active ingredient of most marketed vaginal contraceptive formulations. To determine if these AGs can contact sperm and inhibit acrosin when mixed with the entire human ejaculate for a short period of time (roughly imitating clinical conditions), the inhibitors were added to semen at various concentrations for 2 min, after which the seminal plasma and unbound inhibitor were removed from the sperm by Ficoll centrifugation. Subsequently, the total arginine amidolytic activity of the spermatozoa was determined spectrophotometrically after a combined treatment that resulted in extraction, proacrosin activation, and reaction with substrate. Dose-response curves were prepared. All AGs studied were effective inhibitors of the amidolytic activity under these conditions, with ED50 values (the dose levels at which half of the acrosin associated with 10(6) sperm is inhibited) ranging from 10(-5) to 10(-7) M. To determine the effect on the proteolytic activity of individual spermatozoa, the experiment was repeated with 4'-acetamidophenyl 4-guanidinobenzoate (AGB), and the protease released from the sperm was measured by the gelatin-plate assay. The inhibition results were similar to those obtained by extraction of the spermatozoa and measurement of amidolytic activity. Thus, when mixed with the human ejaculate, AGs interact rapidly with spermatozoa to inhibit both their arginine amidolytic and proteolytic activity (probably due primarily or only to inhibition of acrosin) and remain bound even after removal of the seminal plasma. These data encourage further study of the compounds for contraceptive purposes.

Tolerance to glyceryl trinitrate patches: prevention by intermittent dosing

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The effect of thrombolytic therapy with anisoylated plasminogen streptokinase activator complex on the indicators of myocardial salvage

The role of anisoylated plasminogen streptokinase activator complex (APSAC) in acute myocardial infarction, in effecting thrombolysis, in limiting infarct size and in preserving myocardial function, was assessed by comparing APSAC and placebo in a double-blind, randomised trial. Between October 1984 and April 1985, 43 patients (mean age 57.3 years) with evolving infarctions (19 anterior/24 inferior) were randomised. All patients received treatment within 3 hours of the onset of pain. Patients over 70 years of age or with contraindications to thrombolytic therapy were excluded. Response to therapy was assessed by comparing reductions in summated ECG R wave amplitude and changes in QRS score at 24 hours and 7 days in the leads with ST abnormalities on admission. Radionuclide ejection fractions (EF) were performed 2 to 6 months after infarction. Evidence of successful reperfusion was based on non-invasive parameters. Mean time to peak cardiac enzyme release was shorter in the active treatment group, indicating effective thrombolysis (11.5 hours vs 17.6 hours; p less than 0.01). No differences were found in R wave reduction or QRS score at either 24 hours or 7 days, between active and placebo groups in total or when divided by infarct site. No difference was seen between the EFs of the groups in total or between inferior infarct groups. The mean EF of the treated anterior group was higher than that of the untreated group (p less than 0.05). Successful thrombolysis was seen in the actively treated group. Evidence of myocardial salvage and preservation was seen among treated patients with anterior infarcts only.

Flecainide--an intravenous infusion regimen

An intravenous infusion regimen for flecainide was studied in 12 patients. Therapeutic drug levels were rapidly established and maintained throughout the 48-h infusion period. Two patients were withdrawn because of possible drug related problems, but in general the regimen seemed both effective and well tolerated.

Absorption of phenylbutazone from a paste formulation administered orally to the horse

The absorption pattern of phenylbutazone was studied in five horses during administration of the drug in a paste formulation on days 1, 5, 8 and 12 of a 12-day dosing schedule. Since two or more plasma concentration peaks were usually obtained following each oral dose, it was concluded that phasic absorption was a particular feature of the oil:water formulation of the product. Possible causes of this unusual absorption pattern are discussed and the therapeutic implications of both phasic absorption and the recorded values of Cmax, tmax and AUC024 for phenylbutazone and its active metabolite oxyphenbutazone are considered.

Percutaneous removal of a fractured right heart catheter from the apex of the right ventricle

A 58-year-old woman underwent right and left heart catheterization for suspected ischaemic heart disease with ventricular tachycardia. During the procedure a Bourassa catheter fractured and lodged at the right ventricular apex. Under general anaesthesia and radiographic screening the fragment was removed using a bronchoscopy biopsy forceps via the jugular vein after other methods had failed. This case highlights the need for familiarity with several techniques for the removal of such fragments.

Amiodarone pulmonary toxicity: clinical and subclinical features

In a prospective study of lung function of 34 patients taking amiodarone, 24 showed no functional changes but 10 developed a sustained fall in CO transfer factor (TLCO) exceeding 15 per cent. These patients had on average received a higher dose of drug in the first three months of treatment. Seven showed no clinical or radiographic changes and TLCO improved with reduction in drug dose. The other three patients developed florid clinical and radiographic features of amiodarone pulmonary toxicity. All three had impaired TLCO before receiving amiodarone. During the course of the prospective study amiodarone pulmonary toxicity was diagnosed in four other patients. Lung tissue was examined in five of the seven patients with clinical toxicity and showed alveolar wall thickening, exudation and interstitial and intra-alveolar fibrosis with prominent 'foamy' macrophages. Electron microscopy of macrophages showed numerous lysosomal multilamellar bodies, which were demonstrated by energy dispersive X-ray analysis to contain iodine, a constituent of the amiodarone molecule. Two of the patients with clinical toxicity died of respiratory failure; the other five showed gradual improvement on withdrawal of the drug and treatment with corticosteroids. Subsequent withdrawal of steroids was associated with clinical and/or functional deterioration in five patients. A separate autopsy study of the lungs of eight patients dying during treatment with amiodarone, but without clinically-recognised toxicity, showed that an alveolitis had been present in two and prominent 'foamy' macrophages were seen in the lungs of six patients. We conclude that clinical and subclinical effects of amiodarone on the lung are common. The clinical syndrome may be easily misdiagnosed as pulmonary oedema. Subclinical changes in lung function are usually reversible, but whether they herald clinical toxicity if treatment is continued without modification is not established. The presence of 'foamy' macrophages may simply reflect exposure to the drug rather than clinically-important toxicity.

Aortic root abscess complicating bacterial endocarditis. Demonstration by computed tomography

A 68 year old man with an aortic valve prosthesis was admitted to hospital with Staphylococcus aureus endocarditis. Despite antibiotic treatment he continued to be pyrexial. Computed tomography identified a probable abscess between the root of the aorta and the left atrium. The presence of an abscess in this location was subsequently confirmed at operation. Computed tomography is a useful additional diagnostic method for identifying this potentially lethal complication of bacterial endocarditis.

Role of exercise testing early after myocardial infarction in identifying candidates for coronary surgery

It has been suggested that ST depression in lead V5 or equivalent on early exercise testing after acute myocardial infarction predicts a high risk of death. To evaluate exercise testing and radionuclide ventriculography in this context 103 consecutive patients with myocardial infarction who were able to undertake a limited exercise test before discharge from hospital were exercised and underwent gated blood pool scanning. No serious complications resulted from exercise testing. Twenty nine patients developed ST depression in lead V5, 19 had exertional hypotension, 31 developed a heart rate of greater than or equal to 130 beats/min, and 15 had complex ventricular arrhythmias. Death during the first year after discharge from hospital was associated with exertional hypotension (p less than 0.001) and a heart rate on exercise testing of greater than or equal to 130 beats/min (p less than 0.05); these two variables identified all nine deaths. Inability to complete the exercise protocol for any reason was also predictive of death (p less than 0.01). Ventricular arrhythmias and ST depression in lead V5 induced by exercise were not significantly associated with an increased risk of death. The mean (SD) radionuclide ejection fraction in the patients who died was 29 (16%) compared with 43 (11)% in the patients who survived (p less than 0.001). ST changes on exercise testing after myocardial infarction appear to be less predictive of later complications than haemodynamic signs, which may indicate left ventricular damage rather than ischaemia.