Rapid experimental evolution of reproductive isolation from a single natural population.

Ecological speciation occurs when local adaptation generates reproductive isolation as a by-product of natural selection. Although ecological speciation is a fundamental source of diversification, the mechanistic link between natural selection and reproductive isolation remains poorly understood, especially in natural populations. Here, we show that experimental evolution of parasite body size over 4 y (approximately 60 generations) leads to reproductive isolation in natural populations of feather lice on birds. When lice are transferred to pigeons of different sizes, they rapidly evolve differences in body size that are correlated with host size. These differences in size trigger mechanical mating isolation between lice that are locally adapted to the different sized hosts. Size differences among lice also influence the outcome of competition between males for access to females. Thus, body size directly mediates reproductive isolation through its influence on both intersexual compatibility and intrasexual competition. Our results confirm that divergent natural selection acting on a single phenotypic trait can cause reproductive isolation to emerge from a single natural population in real time.

Preventing neural tube defects with folic acid: nearly 20 years on, the majority of women remain unprotected.

Many countries, including the USA and Canada, have implemented fortification of foods with folic acid, however the British Government only issues advice that supplements should be taken before and after conceiving. In this study, information was collected from women attending antenatal clinics to understand current levels of compliance with health advice and to investigate what is driving womens' behaviour. Eighty-nine percent of women consumed supplements but only 31% took folic acid prior to conceiving. Hence, the vast majority are starting too late to prevent neural tube defects (NTDs). Educational achievement, income and marital status emerged as the most significant factors influencing non-compliance. GPs and midwives were the main catalyst for women starting folic acid, however, 81% of these women started post-conception. When asked why they took folic acid, the majority of women did not mention the association with NTDs. Forty-one percent of women who did not take the supplements at all were unaware that it was recommended that they should. Fortification of UK food products offers a major public health opportunity. In the absence of fortification, gaps in the public health message need to be addressed. GPs and midwives cannot be relied upon alone to educate these women.

Military Aid to the Civil Authorities: a Defence Medical Services perspective.

This paper describes the policy and principles for the provision of Military Aid to the Civil Authorities (MACA). It emphasises the importance of following the proscribed process in order to avoid possible political, legal, reputational and financial pitfalls. It outlines the broader military application of MACA before focusing on where the Defence Medical Services can contribute, drawn from recent experiences and identifying other capabilities that may be of utility. It draws heavily from Joint Doctrine Publication 02 and is quoted with the agreement of the Developments, Concepts and Doctrine Centre.

A specific thromboxane receptor blocking drug, AH23848, reduces platelet deposition on vascular grafts in man.

The antithrombotic effect of a specific thromboxane A2 receptor blocking drug, AH23848, on radio-labelled platelet deposition in mature Dacron aorto-bifemoral grafts has been evaluated in patients. Thirty patients were randomly allocated to AH23848 70 mg, aspirin 300 mg plus dipyridamole 75 mg or placebo 8-hourly for 9 days. AH23848 inhibited platelet aggregation induced by the thromboxane A2 mimetic U-46619; no such effect was observed with aspirin plus dipyridamole. 111In-platelet uptake was measured as the thrombogenicity index (TI) which is a measure of the daily rate of accumulation of platelets by the graft. The mean (s.e. mean) value of 0.193 (0.029) on placebo was significantly reduced to 0.115 (0.022) by AH23848 (p less than 0.05) but only to 0.175 (0.028) by aspirin plus dipyridamole. There was no difference in mean platelet life span between the three treatment groups. The pronounced antithrombotic effect of AH23848 implicates thromboxane A2 in the process of platelet deposition in arterial prostheses and demonstrates the considerable promise of thromboxane receptor blocking drugs as antithrombotic therapy.

The effects of thromboxane antagonism on the transit time of platelets through the spleen.

The spleen is well-known as a site for platelet pooling, although the mechanisms controlling intrasplenic platelet transit are essentially unknown. We tested the possibility that thromboxane A2 might be involved in this control by measuring intrasplenic platelet transit time in 10 subjects receiving a specific thromboxane A2 receptor antagonist (AH23848B; 70 mg; Glaxo Group Research Ltd), in 10 receiving aspirin (300 mg) plus dipyridamole (75 mg), and in 9 receiving placebo. All doses were administered 3 times daily commencing 4 days prior to transit time measurement. Mean intrasplenic platelet transit time was measured by monitoring the kinetics of equilibration of 111In radiolabelled platelets between blood and spleen following intravenous injection. There was no difference between the mean transit time in the 3 groups of subjects, lending no support to the hypothesis that thromboxane A2 is involved in the control of platelet traffic through the spleen.

The cancer recognition (CARE) antibody test.

The cancer recognition (CARE) antibody (Ab) test is a serologic assay for a specific IgM that is elevated in cancer patients. All tests are measured using an indirect enzyme-linked immunosorbent assay (ELISA) of human serum. The target polypeptide in the CARE Ab test is the IgM binding epitope (LT-11) of the CARE antigen (Ag) consisting of a 16 mer structure that has been produced synthetically. The mean relative concentration (MRC) is determined relative to standard, normalized human plasma. Non-parametric analysis showed median MRC values of healthy volunteers (HVs) with no history of cancer (n =47), family history of cancer (n = 126) and a previous cancer history (n = 24) to be 26, 34 and 46, respectively. It was determined that there was no significance found among the medians of the three HV groups (P = 0.53). The specificity of the HV types was between 87 and 98%. Benign/non-cancer surgical patients (n = 27) had a median value of 20 with a specificity of 96%. The cancer patients (n = 61) had a median value of 246 with a sensitivity of 89%. There was a significant difference between the HV and cancer patients (P < 0.0001) as well as between the benign/surgical non-cancerous group and cancer patients (P < 0.0001). The IgM antibody is heat stable at room temperature for two days versus being frozen at -80 degrees C (r2 = 0.97). Either serum or plasma samples may be used in the CARE Ab test (r2 = 0.92). The CARE Ab was almost exclusively IgM with no serum conversion to IgG in sequential measurements of patients with cancer over a six-month period. Preliminary data from patients undergoing post-operative cancer treatment showed that decreasing Ab levels revealed patients negative for residual cancer or undergoing remission, while relapsing patients show an increase in Ab levels. A return to a positive Ab level shortly after treatment is a poor prognostic sign while in advanced cancers the Ab levels may be depressed significantly.

Diminutive pulmonary artery growth following right ventricular outflow tract enlargement.

We have assessed the clinical results and angiographic pulmonary artery growth following construction of the right ventricular outflow tract in 10 children with tetralogy of Fallot or pulmonary atresia. All cases were associated with diminutive pulmonary arteries and considered unsuitable for total corrective surgery. The mean age of the children was 34 months, mean weight 10 kg and mean body surface area 0.48 m2. The right ventricular outflow tract was constructed by insertion of a patch of dura mater (5 patients), pericardium (2 patients), homograft valved conduit (2 patients) and infundibulectomy (1 patient). The ventricular septal defect was not closed. Study of the patients between 13 and 37 months postoperatively revealed an increase in mean arterial oxygen saturation of 22% (P less than 0.01) and a fall in mean haemoglobin concentration of 1.6 g% (P less than 0.05). Overall change in pulmonary artery diameter compared to that of the trachea was insignificant although in individual cases a 50% increase in diameter was shown. Palliation of symptoms was equivalent to conventional shunting procedures. Closure of the ventricular septal defect was performed successfully in 2 patients at a later date.

The surgery of aortic valve disease in neonates, infants and children.

The pre-operative findings and surgical results of forty-three patients under thirteen years of age undergoing isolated aortic valve surgery are reported. Twenty-six underwent open aortic valvotomy for isolated aortic valve stenosis. Of the nine who died, five were neonates. These deaths are attributed to an underdeveloped myxoid valve and aortic valve ring. Eleven children underwent excision of the subvalvar diaphragm but four developed asymptomatic left ventricular strain on ECG and required re-operation. There was one death. One child underwent successful surgery for supravalvar stenosis. Five children underwent surgery for isolated aortic regurgitation. Two underwent repair, but one required aortic valve replacement for uncontrolled regurgitation. Three had aortic valve replacement as a primary procedure. The management of left ventricular outflow tract obstruction and the choice of replacement valve is discussed.

Mitral valve surgery in infants and children.

The pre-operative findings and surgical results of forty-three patients under thirteen years of age undergoing mitral valve surgery, are presented. Eight underwent surgery for mitral stenosis. Four had open mitral valvotomy with a satisfactory result, one developed severe regurgitation which required mitral valve replacement. Two had primary valve replacement and two had excision of a mitral subvalvar diaphragm. Thirty five children underwent surgery for mitral regurgitation. Twelve had a mitral annuloplasty. Two of these developed further regurgitation which required mitral valve replacement. Twenty one children had primary mitral valve replacement. The results and choice of valve replacement are discussed.

The effects of platelet inhibitors on platelet uptake and restenosis after femoral angioplasty.

OBJECTIVE: To investigate the effects of two platelet inhibitors, aspirin and iloprost, on platelet uptake and restenosis at the site of angioplasty in patients undergoing femoral or popliteal angioplasty. EXPERIMENTAL DESIGN: Prospective, open, randomised group comparison. SETTING: Two university hospitals. PATIENTS: 43 patients undergoing femoral or popliteal angioplasty were randomised. INTERVENTIONS: Patients received either aspirin (300 mg/day), iloprost (8 hours/day i.v. infusion) or no antiplatelet medication during angioplasty and on the subsequent two days. MEASURES: Platelet uptake was measured using 111Indium-labelled platelets. Restenosis was assessed by repeat angiography at 3 months and clinical symptoms up to 12 months. RESULTS: Median changes in platelet uptake were similar in the three treatment groups, but all platelet radioactivity ratios > 2.0 occurred in the control group. Restenosis at 3 months was observed in 3 control, 5 aspirin and 1 iloprost patient. Further surgical intervention was performed in 3 control and 3 aspirin patients, but in none of the iloprost patients up to 12 months after angioplasty. CONCLUSIONS: Antiplatelet therapy may prevent large increases in platelet deposition at the angioplasty site, but the link between platelet deposition and restenosis was not substantiated in this study.

Radiolabeled platelets in detecting the source of recurrent pulmonary emboli--a case report.

Multiple pulmonary emboli are recognized to be the cause of progressive pulmonary failure. In these patients, the source of emboli may be difficult to detect, even by venography. The authors describe the use of autologous Indium 111-labeled platelets to locate the origin in a patient with progressing right heart failure.

Teaching socially appropriate behavior to eliminate hoarding in a brain injured adult.

A brain injured male hoarded large quantities of unuseable items at every opportunity. The treatment consisted of two phases. First, he was taught to collect baseball cards. Second, after each meal, the client was provided with an apron and a glove and asked to pick up trash in the area and deposit the trash in an appropriate receptacle. If he hoarded, he was told not to pick up trash without his apron and glove and escorted to a quiet area for about 10 seconds. The procedure was successful in suppressing the behavior within 8 days.

Functional urethral obstruction in 3 dogs: clinical and urethral pressure profile findings.

Three dogs with dysuria and urine retention caused by excessive functional urethral resistance are described. All dogs had clinical histories and urologic signs that previously would have been classified as detrusor-urethral dyssynergia. Diagnosis of functional urinary obstruction was established by exclusion of anatomic urinary obstruction and confirmed by urethral pressure profilometry. In 2 cases, multiple pressure deflections recorded in the urethral pressure profile suggested spasm of urethral musculature, whereas in a 3rd dog, abnormally high pressures were recorded along a portion of the proximal urethra. Functional urinary obstruction was associated with prostatitis in 1 dog and with a history of urethral calculi in 1 dog, and no underlying disorder could be identified in the remaining dog. All 3 dogs improved with medical treatments that included alpha adrenergic antagonists. The etiology, diagnosis, and pharmacologic management of functional urinary obstruction are discussed.

Methods for studying leukocyte filterability in undiluted blood from intermittent claudicants.

Leukocytes are characterised from their influence on the filterability of undiluted blood from patients with PAOD (intermittent claudicants - Fontaine Stage II) and a group of sex and age-matched controls. Undiluted blood was filtered through 5 microm Nuclepore (Hemafil) filters for 300 s, at 711 Pa and room temperature, using a custom-made constant pressure filtrometer. Four populations of leukocytes are identified in both groups. In the control group, 94.4% of the leukocytes are identified as fast leukocytes with a transit time of 1.8 s. The remaining white cells are recognised as slow flowing leukocytes and subdivided into three further sub-populations. The first of these (SL1; 2.8% of total leukocyte count) is characterised by a transit time of 31.7 s, a second population (SL2; 1.5% of total leukocyte count) by a transit time of 145.8 s while the remaining cells are identified as pore blockers (PB) under these conditions. A similar rheological classification is valid in the patients but the sum of the three minor populations is elevated compared to controls (p = 0.001) although there is no overall leukocytosis. The only significant difference in flow properties of any blood cells, between the two groups of volunteers, is seen in the major population of leukocytes with an elevated transit time of 2.4 s. Stepwise regression analysis identifies the concentration of fast leukocytes, SL2 and PB as the major variables affecting blood flow through the filter. It is argued that the higher concentration of SL2 and PB probably reflect the increased sensitivity of neutrophils to physical stimuli.

Quantitative urinalysis in healthy Beagle puppies from 9 to 27 weeks of age.

UNLABELLED: To evaluate indices of renal function in healthy, growing Beagle puppies from 9 to 27 weeks of age and to determine whether indices change with age during this period. Animals-6 healthy Beagle puppies. PROCEDURE: Urine collections were performed at 2-week intervals in puppies 9 to 27 weeks old. Daily excretion of urinary creatinine, protein, sodium, potassium, chloride, phosphorus, and calcium were determined, as were quantitative urinalyses including endogenous creatinine clearance, urine protein-to-creatinine ratios (UPr/C), and fractional clearances of sodium (FNa), potassium (FK), chloride (FCI), calcium (FCa), and phosphorus (FP). RESULTS: Significant differences among age groups were detected for endogenous creatinine clearance, and daily urinary protein, potassium, calcium, and phosphorus excretion. Significant differences also existed among age groups for UPr/C, FNa, FK, FCI and FP. Age-related effects fit a linear regression model for FNa, UPr/C, daily phosphorus excretion, and daily protein excretion. Quadratic regression models were judged most appropriate for endogenous creatinine clearance, FK, daily chloride excretion, and daily potassium excretion. Endogenous creatinine clearance measurements higher than adult reference ranges were observed from 9 to 21 weeks of age. The FNa, FK, FCI, FCa, and FP were slightly higher than those reported for adult dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Selected results of quantitative urinalyses in healthy 9- to 27-week-old Beagle puppies differ with age and differ from those measured in adult dogs. Diagnostic measurements performed in puppies of this age range should be compared with age-matched results when possible.

Adenocarcinoma of the middle ear with osteolysis of the tympanic bulla in a cat.

Peripheral vestibular disease and lethargy were attributed to an adenocarcinoma in the middle ear of a 10-year-old cat. The tumor was invasive, inducing severe lysis of the tympanic bulla and adjacent temporal bone. Direct invasion to the meninges and brainstem also was observed. Neoplasms of the middle ear are rare in cats, with squamous cell carcinomas reported most commonly, but should be considered as causes of chronic otitis or signs of peripheral vestibular disease.

Evaluation of results of preoperative urodynamic measurements in nine dogs with ectopic ureters.

Cytometrographic studies and urethral pressure profiles were performed to objectively assess the functional status of the urinary bladder and urethra in 9 dogs with congenital ectopic ureters. Functional abnormalities of the urinary bladder or urethra were detected in 8 of 9 (89%) dogs. Cystometrographic evidence of reduced bladder capacity was detected in 4 (44%) dogs, and abnormalities in urethral pressure profiles were consistent with urethral incompetence in 6 (67%) dogs. Dogs with urethral pressure profile abnormalities were treated with phenylpropanolamine hydrochloride, and the urethral pressure profile was reevaluated. Urethral pressure measurements obtained before surgery (3 dogs) and after phenylpropanolamine (6 dogs) were used to predict the likelihood of continence after surgery. Predicted outcomes included continence maintained without medication (3 dogs), continence maintained with phenylpropanolamine (2 dogs), and persistent incontinence despite phenylpropanolamine administration (4 dogs). After surgical repair of ectopic ureters, 2 of 9 (22%) dogs were continent without medication, and 2 (22%) maintained continence with phenylpropanolamine treatment. Various degrees of incontinence persisted in 5 of 9 (56%) dogs, 4 of which had urethral incompetence that had been documented as poorly responsive to phenylpropanolamine administration prior to surgery. Predicted outcomes were consistent with actual outcomes in 8 of 9 (89%) dogs, with predictions of incontinence proving accurate in 4 of 4 (100%) dogs and predictions of continence proving accurate in 4 of 5 (80%) dogs. Urodynamic assessment of dogs with ectopic ureters appears to be valuable for identifying concurrent functional abnormalities of the urinary bladder and urethra and for predicting postoperative outcome.

Feline urodynamic procedures.

Urodynamic procedures are those studies which investigate the process of storage and evacuation of urine in the lower urinary tract, usually by recording pressure or flow characteristics in the urinary bladder or urethra. Cystometric techniques, urethral pressure profilometry, electromyography, and evoked potentials have been adapted for use in cats. The applications and limitations of each of these techniques are discussed.

Pharmacologic management of feline lower urinary tract disorders.

Pharmacological recommendations for the treatment of lower urinary tract disorders in cats are rapidly evolving as more is learned about the physiology and pathophysiology of the feline urinary bladder and urethra. Recent investigations and clinical observations have led to reconsideration of previously prescribed treatments and to the use of new and alternative pharmacologic agents. Pharmacologic agents used in the management of common lower urinary tract disorders in cats, including urinary tract infections, idiopathic lower urinary tract inflammation, urinary incontinence, urine retention, and urinary elimination disorders, are reviewed.