Caesarean scar pregnancy in the UK: a national cohort study

OBJECTIVE

To estimate the incidence of caesarean scar pregnancy (CSP) and to describe the management outcomes associated with this condition.

DESIGN

A national cohort study using the UK Early Pregnancy Surveillance Service (UKEPSS).

SETTING

86 participating Early Pregnancy Units.

POPULATION

All women diagnosed in the participating units with CSP between November 2013 and January 2015.

METHODS

Cohort study of women identified through the UKEPSS monthly mailing system.

MAIN OUTCOME MEASURES

Incidence, clinical outcomes and complications.

RESULTS

102 cases of CSP were reported, with an estimated incidence of 1.5 per 10 000 (95% CI 1.1-1.9) maternities. Full outcome data were available for 92 women. Management was expectant in 21/92 (23%), medical in 15/92 (16%) and surgical in 56/92 (61%). The success rates of expectant, medical and surgical management were 43% (9/21), 46% (7/15) and 96% (54/56), respectively. The complication rates were 15/21 (71%) with expectant, 9/15 (60%) with medical and 20/56 (36%) with surgical management. Discharge from care (median number of days) was 82 (range 37-174) with expectant, 21 (range 10-31) with medical and 11 (range 4-49) with surgical management.

CONCLUSIONS

Surgical management appears to be associated with a high success rate, low complication rate and short post-treatment follow up.

TWEETABLE ABSTRACT

Surgery for CSP appears to be successful, with low complication rates and short post-treatment follow up.

Diabetes is associated with impairment of uterine contractility and high Caesarean section rate

AIMS/HYPOTHESIS

The prevalence of births worldwide complicated by diabetes mellitus is increasing. In the UK, for example, <25% of diabetic women have a non-instrumental vaginal delivery. Strikingly, more than half the Caesarean sections (CS) in these patients are non-elective, but the reasons for this are not understood. We have tested the hypothesis that poor myometrial contractility as a consequence of the disease contributes to this high CS rate.

METHODS

We compared spontaneous, high K depolarisation and oxytocin-induced contractions from diabetic and matched control patients having an elective CS. To investigate the mechanism of any differences we measured intracellular Ca, and performed western blotting and compared the tissues histologically.

RESULTS

There was significantly decreased contraction amplitude and duration in uteri from diabetic compared with control patients, even when possible confounders such as BMI were analysed. Reduced intracellular calcium signals and expression of calcium entry channels were found in uteruses from diabetic patients, which, along with a reduction in muscle content found on histological examination, could explain the reduced force. Myometrium from diabetic patients was responsive to oxytocin, but still did not reach the levels found in non-diabetic patients.

CONCLUSIONS/INTERPRETATIONS

These are the first data investigating myometrium in diabetic patients and they support the hypothesis that there is poorer contractility even in the presence of oxytocin. The underlying mechanism is related to reduced Ca channel expression and intracellular calcium signals and a decrease in muscle mass. We conclude that these factors significantly contribute to the increased emergency CS rate in diabetic patients.

In vitro myometrial contractility reflects indication for caesarean section

OBJECTIVE

To assess the extent to which in vitro measurements of myometrial contractility reflect the clinical indication for caesarean section.

DESIGN

A prospective, observational hypothesis-generating study.

SETTING

Women were recruited from Liverpool Women's NHS Foundation Trust and experiments were performed in the Physiology Department at the University of Liverpool.

POPULATION

Myometrial samples were taken from women undergoing a caesarean section during labour (n = 50) or from women having a repeat nonlabouring caesarean section (n = 70).

METHODS

The demographic characteristics of the women and indications for current and previous caesarean sections were recorded. The force, frequency and duration of spontaneous contractions of myometrial strips, and changes in the intracellular calcium concentration of the strips, were measured. Kruskall-Wallis and post hoc tests were used to assess the significance of differences between groups.

RESULTS

Samples from women whose caesarean section was for fetal distress/acidosis (scalp pH <7.2) contracted with more force than those from women whose caesarean section was for delay in the first stage of labour (P < 0.001). For repeat, nonlabouring caesarean sections, samples from women whose first caesarean section was for fetal distress/acidosis also contracted with more force than did samples from women whose first caesarean section was for delay in the first stage of labour (P = 0.03).

CONCLUSIONS

These findings suggest that the myometrium contracts with greater force in women who have a caesarean section for fetal distress.

Severe H1N1 virus in pregnancy requiring extracorporeal membrane oxygenation and lobectomy

Prompt diagnosis and treatment of H1N1 is crucial during pregnancy to prevent major morbidity and mortality as the virus poses an increased risk of severe illness in pregnant women. Currently, there is limited obstetric literature concerning pregnancy and the pandemic swine flu outbreak in the UK. Although there was a concerted effort to stockpile the HIN1 virus vaccinations, critical care adult extracorporeal membrane oxygenation is only available in one centre in the UK.

Recurrent miscarriage and antiphospholipid antibodies: prognosis of subsequent pregnancy

BACKGROUND

 Although women with antiphospholipid antibodies (APLAs) are at increased risk of recurrent miscarriage, the outcome of a subsequent pregnancy is not clearly elucidated.

OBJECTIVES

To assess the pregnancy outcome of a subsequent pregnancy in women with APLAs and compare this outcome with women with unexplained recurrent miscarriage.

METHODS

 We performed a cohort study among all women who attended the Miscarriage Clinic at Liverpool Women's Hospital between 1987 and 2006 after being referred due to recurrent miscarriage (≥2 consecutive pregnancy losses). All women underwent a standardized investigation sequence. Women with other reasons for recurrent miscarriage were excluded.

RESULTS

 A total of 693 women fulfilled the selection criteria, of whom 176 (25%) had APLAs. One hundred and twenty-two (69%) women with APLAs had a subsequent live birth compared with 324 (63%) women with unexplained recurrent miscarriage (OR 1.3, 95% CI 0.9-1.9). No differences were found for birth weight, gestational age, and intra-uterine growth restriction. When treatment was analyzed, 53/67 (79%) of women with APLAs who had received aspirin and heparin during their pregnancy had a live birth, compared with 64/104 (62%) of women with APLAs who received aspirin only (adjusted OR 2.7, 95% CI 1.3-5.8). In unexplained recurrent miscarriage, stratification for treatment showed no differences in outcome.

CONCLUSION

The prognosis of a subsequent pregnancy in women with APLAs is good. Although this was not a randomized clinical trial, combined treatment of aspirin and heparin seemed associated with a better outcome in women with APLAs, but not in women with unexplained recurrent miscarriage.

Recurrent miscarriage and long-term thrombosis risk: a case–control study

BACKGROUND

Recurrent miscarriage has been associated with antiphospholipid syndrome (APS) and other prothombotic conditions. We tested the hypothesis that women diagnosed as having APS as an aetiological factor for their miscarriages were at higher risk of thrombosis than those with idiopathic recurrent miscarriage.

METHODS

A retrospective case-control study was performed using validated questionnaires. A total of 141 women with recurrent miscarriage and APS alone were matched with 141 women with idiopathic recurrent miscarriage for age, number and type of pregnancy loss and number of years of follow-up. A subgroup of eight women included those who initially presented with recurrent miscarriage, thrombosis and APS.

RESULTS

The mean length of follow-up was 7.3 years and response rate 74%. The incidence of thrombosis was similar in the recurrent miscarriage and APS women (6/1000 women-years) and in the idiopathic recurrent miscarriage women (2/1000 women-years) (P = 0.18). All eight women who presented with recurrent miscarriage, APS and thrombosis reported further thrombotic events.

CONCLUSIONS

Both idiopathic and APS-associated recurrent miscarriage were associated with a similar long-term risk of thrombosis.

Conditioned nutritional deficiencies in the cardiomyopathic hamster heart

BACKGROUND

Evidence indicates that nutritional factors may be important in the maintenance of myocyte structure and energetics. The failing myocardium has been reported to exhibit a depletion of several nutrients that are important for the maintenance of intracellular calcium homeostasis and cellular energetics, and levels of oxidative stress. This nutrient depletion may contribute to the progressive deterioration in myocardial structure and function observed in heart failure.

OBJECTIVE

To examine the extent to which advanced cardiomyopathy results in a depletion of nutrients and/or metabolites and antioxidants, and whether supplementation with these nutrients may influence cellular structure or function.

SUBJECTS AND METHODS

Cardiomyopathic hamsters were randomly placed to one of the three following diet groups: chow; control gelled diet; or a supplemented gelled diet that provided taurine, carnitine, coenzyme Q10, selenium, vitamins E and C, creatine, thiamine and L-cysteine. After approximately three months of supplementation, one group of hamsters underwent functional testing using a modified Langendorff technique with biopsy samples taken for electron microscopy. Myocardial nutrient concentrations were determined in a second group of diseased and nondiseased hamsters of the same age.

RESULTS

Cardiomyopathy resulted in a depletion of vitamin E, creatine, carnitine, taurine and coenzyme Q10. Supplementation resulted in improved cardiac ultrastructure, function and contractility compared with nonsupplemented hamsters.

CONCLUSIONS

These studies suggest that heart failure results in 'condition-related nutrient deficiencies' that, once corrected, can significantly impact on heart function and structure.

Effects of estrogen replacement on infarct size, cardiac remodeling, and the endothelin system after myocardial infarction in ovariectomized rats

BACKGROUND

Estrogen may increase the long-term survival of women who have suffered from a myocardial infarction (MI). We examined the acute and chronic influence of estrogen on MI in the rat left coronary artery ligation model.

METHODS AND RESULTS

Female Sprague-Dawley rats (10 to 12 weeks, n=93), divided into 3 groups (rats with intact ovaries, ovariectomized rats administered 17beta-estradiol [17beta-E(2)] replacement, and ovariectomized rats administered placebo 2 weeks before MI), were randomized to left coronary artery ligation (n=66) or sham-operated (n=27) groups. Ten to 11 weeks after MI, rats were randomly assigned to either (1) assessment of left ventricular (LV) function and morphometric analysis or (2) measurement of cardiopulmonary mRNA expression of preproendothelin-1 and endothelin A and B receptors. Acutely, estrogen was associated with a trend toward increased mortality. Infarct size was increased in the 17beta-E(2) group compared with the placebo group (42+/-2% versus 26+/-3%, respectively; P:=0.01). Chronically, wall tension was normalized through a reduction in LV cavity size with estrogen treatment (419+/-41 mm Hg/mm for 17beta-E(2) versus 946+/-300 mm Hg/mm for placebo, P:=0.039). In the LV, there was a 2.5-fold increase in endothelin B mRNA expression after MI in placebo-treated rats (P:=0.004 versus sham-operated rats) that was prevented in the 17beta-E(2) group (P:=NS versus sham-operated rats).

CONCLUSIONS

These results suggest that estrogen is detrimental at the time of MI or early post-MI period, resulting in an increased size of infarct or infarct expansion, but chronically, it can normalize wall tension and inhibit LV dilatation, which may in turn lead to increased long-term survival. Regulation of the endothelin system, particularly the expression of the endothelin B receptor, may contribute to these estrogenic effects.

The tyrosine kinase p56lck is essential in coxsackievirus B3-mediated heart disease

Infections are thought to be important in the pathogenesis of many heart diseases. Coxsackievirus B3 (CVB3) has been linked to chronic dilated cardiomyopathy, a common cause of progressive heart disease, heart failure and sudden death. We show here that the sarcoma (Src) family kinase Lck (p56lck) is required for efficient CVB3 replication in T-cell lines and for viral replication and persistence in vivo. Whereas infection of wild-type mice with human pathogenic CVB3 caused acute and very severe myocarditis, meningitis, hepatitis, pancreatitis and dilated cardiomyopathy, mice lacking the p56lck gene were completely protected from CVB3-induced acute pathogenicity and chronic heart disease. These data identify a previously unknown function of Src family kinases and indicate that p56lck is the essential host factor that controls the replication and pathogenicity of CVB3.

Susceptibility to myocarditis is dependent on the response of alphabeta T lymphocytes to coxsackieviral infection

Viral myocarditis is an important cause of heart failure and dilated cardiomyopathy. T lymphocytes are implicated in myocardial damage in murine models of coxsackievirus B3 (CVB3) myocarditis. We used knockout mice lacking CD4 (CD4(-/-)), CD8 (CD8(-/-)), both coreceptors (CD4(-/-)CD8(-/-)), or the T-cell receptor beta chain (TCRbeta(-/-)) to address the contribution of T-cell subpopulations to host susceptibility to CVB3 myocarditis. Severity of disease was magnified in CD8(-/-) mice but attenuated in CD4(-/-) mice, consistent with a pathogenic role for CD4(+) lymphocytes. Elimination of both CD4 and CD8 molecules from T lymphocytes by genetic knockout better protected mice from myocarditis, demonstrating that both CD4(+) and CD8(+) T cells contribute to host susceptibility. The same benefit occurred in TCRbeta(-/-) mice, with prolonged survival and minimal myocardial disease observed after CVB3 infection. Elevated interferon-gamma and decreased tumor necrosis factor-alpha expression are associated with attenuated myocardial damage in CD4(-/-)CD8(-/-) mice. These results show that the presence of TCRalphabeta(+) T cells enhances host susceptibility to myocarditis. The severity of myocardial damage and associated mortality are dependent on the predominant T-cell type available to respond to CVB3 infection. One mechanism by which CD4(+) and CD8(+) T-cell subsets influence the pathogenesis of myocarditis may involve specific cytokine expression patterns.

Cardiac function and cytotoxic aldehyde production in a murine model of chronic iron-overload

OBJECTIVES

To determine the relationship between the total chronic dose of iron administered, ex-vivo cardiac function and the concentrations of cytotoxic aldehydes in heart tissue of a murine model.

METHODS

In the first experiment, 34 male B6D2F1 mice were randomized to receive intraperitoneal injections of 5, 10 or 20 mg of iron dextran for three weeks, or a placebo control. The mice were subsequently randomized to undergo ex-vivo assessment of cardiac function. In the second experiment, free radical generation, quantified by the presence of 20 separate cytotoxic aldehydes, was assessed in heart tissue of 40 mice that were randomized to receive chronic treatment with various concentrations of iron dextran (100 mg to 300 mg total chronic dose administered), placebo treatment with saline, or no treatment at all (baseline).

RESULTS

Iron-loaded groups displayed dose-dependent depressions of heart rate, systolic pressure, developed pressure, coronary pressure, -dP/dt and +dP/dt, and increases in diastolic pressure. Monotonic dose-dependent increases in total heart aldehydes were observed in the iron-treated groups (r-0.97, p < 0.0001), whereas no significant differences were observed between baseline or time-placebo control groups.

CONCLUSIONS

While no single mechanism is likely to account for the complex pathophysiology of iron-induced heart failure, our findings show that chronic iron-loading in a murine model results in dose-dependent alterations to cardiac function; and results in free radical mediated damage to the heart, as measured by excess concentrations of cytotoxic aldehyde-derived peroxidation products. This is the first description of the effects of excess iron on cardiac function assessed by an ex-vivo Langendorff technique in a murine model of chronic iron-overload.

Tissue expression and immunolocalization of tumor necrosis factor-alpha in postinfarction dysfunctional myocardium

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) is markedly elevated in advanced heart failure. It is not known whether tissue TNF-alpha is elevated in the common setting of myocardial infarction leading to heart failure and what the source of TNF-alpha is. To determine this, we studied the expression and protein localization of TNF-alpha and its 2 main receptors (TNF-R1/R2) in a rat model of large infarction.

METHODS AND RESULTS

Male rats were randomized to proximal left anterior descending ligation. The animals were killed on days 1, 3, 10, and 35 after ligation to examine gene expression and protein production of TNF-alpha and TNF-R1/R2 from the infarct, peri-infarct, and contralateral zones of infarcted heart. There was increased TNF-alpha mRNA production throughout the myocardium at day 1, and detectable expression persisted to day 35 after myocardial infarction. The expression of this cytokine is not confined strictly to the infarct or peri-infarct zones but is expressed by cardiac myocytes within the myocardium in the contralateral normal zone. Changes in gene expression are mirrored initially by augmented protein production within the myocytes. Levels of TNF-alpha protein in the infarct and peri-infarct zones rose early to 8- to 10-fold above normal levels and rose to 4- to 5-fold in the contralateral zone. Finally, expression of the TNF-R1 mRNA transcripts was upregulated at days 3 and 10 after ligation in the infarct and peri-infarct zones, suggesting that the signal transduction pathways necessary for TNF-alpha in the heart remain intact as TNF-alpha biosynthesis increases.

CONCLUSIONS

TNF-alpha is present early in a model of large myocardial infarction and is sustained into the later stage within the myocardium. Expression of this cytokine is not only confined strictly to the infarct or peri-infarct zone but is expressed by cardiac myocytes within the myocardium contralateral to the infarct. Therefore TNF-alpha production forms a part of an important intrinsic myocardial stress response system to injury.

A serine elastase inhibitor reduces inflammation and fibrosis and preserves cardiac function after experimentally-induced murine myocarditis

In viral myocarditis, inflammation and destruction of cardiac myocytes leads to fibrosis, causing progressive impairment in cardiac function. Here we show the etiologic importance of serine elastase activity in the pathophysiology of acute viral myocarditis and the therapeutic efficacy of an elastase inhibitor. In DBA/2 mice inoculated with the encephalomyocarditis virus, a more than 150% increase in myocardial serine elastase activity is observed. This is suppressed by a selective serine elastase inhibitor, ZD0892, which is biologically effective after oral administration. Mice treated with this compound had little evidence of microvascular constriction and obstruction associated with myocarditis-induced ischemia reperfusion injury, much less inflammation and necrosis, only mild fibrosis and myocardial collagen deposition, and normal ventricular function, compared with the infected nontreated group.

Chronic endothelin-1 blockade preserves myocardial contractility in dilated cardiomyopathy

Endothelin-1 (ET-1) is known to have positive inotropic effects in isolated cardiac muscle strips. ET-1 levels are elevated in congestive heart failure (CHF). We investigated the effects of ET-1 on contractility and cardiac relaxation (lusitropy) of the intact healthy murine heart and myocarditic/cardiomyopathic heart by chronic oral treatment with a mixed ETA/ETB blocker SB217242. Chronic ET-1 blockade of normal hearts resulted in depression of contractility and lusitropy of the normal heart but preservation and enhancement of contractility and lusitropy in myocarditic animals, in which ET-1 cardiac content is elevated. This suggests that ET-1 is important in the basal contractility and relaxation of the normal heart but that its chronic elevation in CHF causes impairment of cardiac systolic and diastolic performance.

Favorable left ventricular remodeling following large myocardial infarction by exercise training. Effect on ventricular morphology and gene expression

Continued adverse remodeling of myocardium after infarction may lead to progressive ventricular dilation and heart failure. We tested the hypothesis that exercise training in a healed myocardial infarction-dysfunction rat model can favorably modify the adverse effects of ventricular remodeling including attenuation of abnormal myosin gene expression. Sprague-Dawley rats were subjected to either proximal LAD ligation or sham operation. At 5 wk after the operation, animals were randomly assigned to sedentary conditions or 6 wk of graduated swim training, creating four experimental groups: infarct sedentary (IS), infarct exercise (IE), sham sedentary (SS), and sham exercise (SE). At 11 wk all rats were sacrificed and analyzed. Compared to sedentary infarct controls, exercise training attenuated left ventricular (LV) dilation and allowed more hypertrophy of the non infarct wall. The exercise-trained hearts also showed a reduction in the estimated peak wall tension. Northern blot analysis showed an increase in beta-myosin heavy chain expression in the hearts of the sedentary infarction group soon after infarction when compared to sham controls. However, with exercise training, there was a significant attenuation of the beta-myosin heavy chain expression in the myocardium. Exercise training in a model of left ventricular dysfunction after healed myocardial infarction can improve the adverse remodeling process by attenuating ventricular dilation and reducing wall tension. The abnormal beta-myosin expression was also attenuated in the exercise trained group. This is evidence that abnormal gene expression following severe myocardial infarction dysfunction can be favorably modified by an intervention.

Effects of oxygen free radicals and scavengers on the cardiac extracellular collagen matrix during ischemia-reperfusion

OBJECTIVE

Collagen is lysed early during ischemia-reperfusion, but whether this is due to ischemia or reperfusion injury is not known. The effect of oxygen free radicals and free radical scavengers on left ventricular hemodynamics, myocardial morphology and collagen content were studied in an isolated, Langendorff-perfused rat heart model of regional ischemia-reperfusion.

METHODS

All hearts received left anterior descending coronary artery ischemia for 20 mins. Group 1 had ischemia only; group 2 had ischemia followed by reperfusion with oxygenated Krebs-Henseleit buffer for 20 mins; group 3 had oxygen free radicals generated by hypoxanthine and xanthine oxidase during reperfusion; group 4 had free radical scavengers with superoxide dismutase plus catalase; group 5 had both oxygen free radicals and free radical scavengers during reperfusion.

RESULTS

Left ventricular developed pressure decreased significantly in group 3 during ischemia followed by reperfusion (58 +/- 3.1 mmHg versus 42 +/- 2.4 mmHg, P = 0.004), but did not change significantly in any of the other groups. Necrosis score on pathology was highest in group 3; this score also was higher than that in group 5 with free radical scavengers added (3.0 +/- 0.3 versus 2.0 +/- 0.4, P = 0.07) and higher than that of group 2 with reperfusion with buffer only (3.0 +/- 0.3 versus 1.4 +/- 0.5, P < 0.05). Collagen content decreased significantly compared with control in group 3 only with ischemia followed by reperfusion with the addition of oxygen free radicals (18.4 +/- 1.5 versus 11.9 +/- 1.7 g/mg protein, P < 0.05). The addition of free radical scavengers in group 5 mainly attenuated the collagen loss. Scanning electron microscopy revealed profound structural changes of the extracellular collagen matrix in numerous regions of 'stunning' independent of tissue necrosis.

CONCLUSIONS

We conclude that: first, oxygen free radicals trigger significant collagen damage and left ventricular dysfunction during reperfusion; second, these changes extend beyond the ischemic damage alone; and third, free radical scavengers can effectively limit oxygen free radical-induced collagen loss and left ventricular dysfunction.

Alterations in fatty acid metabolism in adriamycin cardiomyopathy

Myocardial fatty acid metabolism may be impaired in adriamycin cardiomyopathy. In order to determine the extent of fatty acid metabolism alterations, we measured steady state [14C]palmitate oxidation and the incorporation of [14C]palmitate into the neutral lipid pool in a rat model of adriamycin cardiomyopathy. Isolated hearts from control rats and rats treated with adriamycin were perfused with 1.2 mmol/l of [14C]palmitate for 30 min to achieve steady state oxidation measured as [14C]O2 production; then perfused with 1.2 nmol/l of unlabelled palmitate. Hearts were killed early (0-5 min) or late (10-30 min) after the [14C]palmitate perfusion, to determine incorporation into the neutral lipid pool, and neutral lipid utilization. In the control group steady state oxidation was reached in 10 min ([14C]O2 production = 580 +/- 61 nmol/min/g dry wt) of perfusion. In the adriamycin treated group, mean CO2 production was significantly reduced at 10 min (329 +/- 44 nmol/min/g dry wt, P < 0.01 v control). At 30 min, [14C]O2 production in the treated group was not significantly different than controls (521 +/- 65 nmol/min/g dry wt v 617 +/- 36 nmol/min/g dry wt, P = N.S.). The incorporation of [14C]palmitate into the neutral lipid pool measured in the early subgroup was significantly reduced for adriamycin treated hearts v controls (7.2 +/- 0.6 v 12.0 +/- 1.4 mumol/g dry wt respectively, P < 0.01). In the control group 14C labelled neutral lipid reduced with time to 8.4 +/- 1.1 mumol/g dry wt (P < 0.05) in the late group. The adriamycin group demonstrated no significant change between early and late measurements. In conclusion, in adriamycin cardiomyopathy: (1) there is significant delay in achieving steady state palmitate oxidation, although the steady state rate is near normal; (2) palmitate incorporation into the neutral lipid pool is reduced; (3) neutral lipid pool utilization may also be reduced. These data suggest impaired uptake of palmitate into the cell in adriamycin cardiomyopathy, with a relatively maintained capacity for oxidative metabolism.

Impaired vascular reactivity following angioplasty is mainly due to endothelial injury

Vasoconstriction occurs frequently following coronary angioplasty and is implicated in the pathogenesis of abrupt closure and restenosis. Control of vasomotor tone is regulated in part directly by smooth muscle cells and indirectly through the endothelium. To study the mechanisms underlying vasoconstriction, the effect of angioplasty and endothelial denudation on endothelium-dependent and -independent relaxation was examined in 15 mongrel dogs. Percutaneous transluminal angioplasty and endothelial denudation of the right femoral artery were performed. Endothelial injury was assessed by adhesion of indium-111-labeled platelets. Endothelium-dependent and -independent relaxation were assessed using acetylcholine and nitroglycerin, respectively. Vessels precontracted with potassium chloride and exposed to acetylcholine showed impaired relaxation in both the angioplasty and denuded groups (angioplasty = 14 +/- 5%, denuded = 0 +/- 0%, normal = 73 +/- 12%; P less than 0.05 for both angioplasty and denuded compared to normal). Precontraction with phenylephrine yielded similar results (angioplasty = 16 +/- 8%, denuded = 4 +/- 2%, normal = 39 +/- 10%; P less than 0.05 only for denuded segment compared to normal). Segments precontracted with phenylephrine and exposed to nitroglycerin did not demonstrate impaired relaxation (angioplasty = 73 +/- 9%, denuded = 68 +/- 9%, normal = 71 +/- 7%, P = ns). Mean indium-111 counts were similar in both the angioplasty and denuded segments (2820 +/- 1481 and 2963 +/- 1228 counts/min/g, respectively) compared to a lower count in the normal segment (1514 +/- 956 counts/min/g). Thus, angioplasty produces significant vascular injury and impairment of vasodilator function, comparable to that caused by endothelial denudation alone. This implies that vasoconstriction seen following coronary angioplasty may be due to endothelial injury and the resultant loss of control of vasomotor tone.

Seasonality of cattle feed sources in Pabna, Bangladesh

Cattle feed sources were studied at village level in Pabna district, Bangladesh. A large quantity of feed was offered. In the monsoon the average amount of DM fed to a mature animal of 210 kg was 7.1 kg d-1, consisting of about equal amounts of straw, weeds and leaves. In winter animals grazed for an average of 3.7 hd-1 and were supplemented with 3.9 kg DM d-1 (two-thirds straw). In summer they were offered 5.4 kg DM d-1 (one-third straw and two-thirds weeds and leaves) and they grazed for 0.5 h d-1. The major limiting constraint on cattle production is the quality of the feed offered, particularly in the monsoon period when animals cannot graze. In future, feed quality will become even more of a problem because grazing lands are gradually disappearing.

Comparison of two cattle production systems in Pabna district Bangladesh

In Pabna district, Bangladesh there are two cattle production systems: a draught-oriented system with local Deshi cattle and more milk-oriented production with Pabna Milking Cow (PMC) stock. Deshi animals are smaller than PMC animals. More PMC cows are milked than Deshi cows and the milk off-take of PMC cows is much higher. The calving interval in Deshi cows is one year longer than in PMC cows. The great majority of the bullocks and the bulls are used as draught animals. More than 80% of the Deshi cows also have to work compared with only about half of the PMC cows. The milk off-take of cows used for draught work is 30% less than that of other cows. One of the major differences between the two systems is that PMC cows have access to grazing along the rivers. These areas are increasingly taken up for cropping and the traditional Pabna milk production farming system is gradually being replaced.

Are the kinetics of technetium-99m methoxyisobutyl isonitrile affected by cell metabolism and viability?

To investigate the role of cell viability and metabolism on the myocardial kinetics of a new tracer, technetium-99m-methoxyisobutyl isonitrile (Tc-99m-MIBI), 250 microCi/l Tc-99m-MIBI was infused in isolated rat hearts under constant flow conditions. The hearts were studied after inducing irreversible damage by cytochrome c oxidase inhibitor sodium cyanide (n = 8) or sarcolemmal membrane detergent Triton X-100 (n = 8). The control hearts (n = 6) received no toxins. Mean Tc-99m-MIBI peak accumulation activity was significantly reduced after cyanide (51.1 +/- 44.2% of control, p less than 0.01) and Triton (13.8 +/- 2.7% of control, p less than 0.001) administration. Kinetic studies also showed marked reduction in accumulation rates and marked increase in clearance rates for cyanide (p less than 0.01) and Triton (p less than 0.01) groups compared with controls. Potential changes in regional flow distribution were assessed using microspheres. When peak accumulation activity was corrected for these changes, there remained significant differences between the groups. In the cyanide and Triton groups, irreversible cell injury was confirmed by creatine kinase and lactate dehydrogenase release, triphenyl tetrazolium chloride staining, and electron microscopy. All the cells were viable in the control group. We conclude that the accumulation and clearance kinetics of Tc-99m-MIBI are significantly affected by cell viability. Tc-99m-MIBI kinetics appear to be dependent on sarcolemmal integrity and to a lesser extent on aerobic metabolism.

Chrysotherapy and thrombocytopenia

In a study of the clinical and immunogenetic profiles of 17 patients with rheumatoid arthritis and thrombocytopenia (platelet count less than 150 000/mm3 (150 x 10(9)/l)) due to gold therapy two clinical patterns were distinguished without knowledge of HLA type: group I, an early precipitous thrombocytopenia (10 patients), and group II, a less dramatic fluctuant fall (seven patients). In group I patients the clinical and laboratory features suggested an immune mediated, peripheral destruction of platelets, and all patients in this group were found to be HLA-DR3 positive. Two patients subsequently received penicillamine without toxicity. In group II the basis of thrombocytopenia appeared to be different, and only two patients in this group were HLA-DR3 positive. All group II patients had received penicillamine; four developed a thrombocytopenia. Mechanisms of toxicity in both groups are discussed. It would appear that HLA typing in unlikely to help in predicting all those patients at risk of toxicity during chrysotherapy.