Use of pet food-grade poultry by-product meal as an alternate protein source in weanling pig diets

Three experiments were conducted to evaluate pet food-grade poultry by-product meal (PBM) as a replacement protein source for fish meal (FM), blood meal (BM), and spray-dried plasma protein (SDPP) in weanling pig diets. In the first study, 200 crossbred pigs (initial BW = 6.5 kg) were weaned (21 d) and randomly allotted to one of four dietary treatments, which included a control and three test diets where PBM was substituted for FM, blood products, or both. Experimental diets were fed during Phase I (d 0 to 5 postweaning) and Phase II (d 5 to 19), and a common Phase III diet was fed from d 19 to 26. Overall (d 0 to 26), there was no difference in performance of pigs fed PBM in place of the other ingredients. However, during Phase I, BW (P < 0.05), ADG (P < 0.02), and intake (P < 0.001) in pigs fed diets containing SDPP were greater than those fed diets with PBM. In Exp. 2, the performance of pigs (n = 100, initial BW = 6.5 kg) fed diets containing 20% PBM (as-fed basis, replacing SDPP, BM, FM, and a portion of the soybean meal) in all phases of the nursery diet was compared with a group fed conventional diets without PBM. There were no differences in overall performance (d 0 to 26); however, ADG (P < 0.10) and feed intake were higher (P < 0.01) for pigs fed the conventional diet than for pigs fed the 20% PBM diet during Phase I (d 0 to 5). Experiment 3 was a slope-ratio assay to determine the ability of PBM to replace SDPP. A total of 320 pigs (initial BW = 7.32 kg) was weaned (21 d) and allotted to five treatment groups in three trials in a blocked design with product (SDPP or PBM) as the first factor, and lysine level (1.08, 1.28, 1.49%; as-fed basis) as the second factor. Growth rate increased with increasing lysine (P < 0.05), regardless of the source. These results indicate that PBM can be used in nursery diets in place of blood meal and fish meal without affecting performance. Furthermore, although feeding PBM in Phase I diets was not equivalent to SDPP during the first week, there was no overall difference in performance at the end of the nursery phase.

Testosterone does not adversely affect fibrinogen or tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) levels in 46 men with chronic stable angina

OBJECTIVE

In women, sex hormones cause increased morbidity and mortality in patients with coronary heart disease (CHD) and adversely affect the coagulation profile. We have studied the effect of physiological testosterone replacement therapy in men on coagulation factor expression, to determine if there is an increased risk of thrombosis.

METHODS

Double-blind, randomized, placebo-controlled trial of testosterone in 46 men with chronic stable angina. Measurements of free, total and bioavailable testosterone, luteinising hormone (LH) and follicle-stimulating hormone (FSH), estradiol, plasminogen activator inhibitor-1 (PAI-1), fibrinogen, tissue plasminogen activator (tPA) and full blood count were made at 0, 6 and 14 weeks.

RESULTS

Bioavailable testosterone levels were: 2.58 +/- 0.58 nmol/l at baseline, compared with 3.35 +/- 0.31 nmol/l at week 14 (P < 0.001) after treatment compared with 2.6 +/- 0.18 nmol/l and 2.44 +/- 0.18 nmol/l in the placebo group (P was not significant). There was no change in fibrinogen (3.03 +/- 0.18 g/l at baseline and 3.02 +/- 0.18 g/l at week 14, P = 0.24), tPA activity (26.77 +/- 4.9 Iu/ml and 25.67 +/- 4.4 Iu/ml, P = 0.88) or PAI-1 activity (0.49 +/- 0.85 Iu/ml and 0.36 +/- 0.06 Iu/ml, P = 0.16) with active treatment and no differences between the groups (at week 14, P value 0.98, 0.59 and 0.8 for fibrinogen, PAI-1 and tPA respectively). Haemoglobin concentration did not change over time, in the testosterone group (1.44 +/- 0.02 g/l and 1.45 +/- 0.02 g/l, P = 0.22).

CONCLUSION

Physiological testosterone replacement does not adversely affect blood coagulation status.

Steroid-responsive charles bonnet syndrome in temporal arteritis

The authors report a patient with biopsy-proven temporal arteritis who manifested Charles Bonnet syndrome (CBS). Treatment with steroid resulted in prompt resolution of visual hallucinations, despite persistent visual loss, suggesting that cerebral ischemia is a cofactor for the development of CBS.

Testosterone replacement in hypogonadal men with angina improves ischaemic threshold and quality of life

BACKGROUND

Low serum testosterone is associated with several cardiovascular risk factors including dyslipidaemia, adverse clotting profiles, obesity, and insulin resistance. Testosterone has been reported to improve symptoms of angina and delay time to ischaemic threshold in unselected men with coronary disease.

OBJECTIVE

This randomised single blind placebo controlled crossover study compared testosterone replacement therapy (Sustanon 100) with placebo in 10 men with ischaemic heart disease and hypogonadism.

RESULTS

Baseline total testosterone and bioavailable testosterone were respectively 4.2 (0.5) nmol/l and 1.7 (0.4) nmol/l. After a month of testosterone, delta value analysis between testosterone and placebo phase showed that mean (SD) trough testosterone concentrations increased significantly by 4.8 (6.6) nmol/l (total testosterone) (p = 0.05) and 3.8 (4.5) nmol/l (bioavailable testosterone) (p = 0.025), time to 1 mm ST segment depression assessed by Bruce protocol exercise treadmill testing increased by 74 (54) seconds (p = 0.002), and mood scores assessed with validated questionnaires all improved. Compared with placebo, testosterone therapy was also associated with a significant reduction of total cholesterol and serum tumour necrosis factor alpha with delta values of -0.41 (0.54) mmol/l (p = 0.04) and -1.8 (2.4) pg/ml (p = 0.05) respectively.

CONCLUSION

Testosterone replacement therapy in hypogonadal men delays time to ischaemia, improves mood, and is associated with potentially beneficial reductions of total cholesterol and serum tumour necrosis factor alpha.

A simulation model of brucellosis spread in British cattle under several testing regimes

Brucellosis is a widespread, economically devastating and highly infectious zoonosis. In cattle, infection predominantly is caused by Brucella abortus, and is usually detected in pregnant females through abortions. Great Britain (GB) has been declared free from brucellosis (officially brucellosis free (OBF)) since 1993 and as such is required by European Union (EU) regulations to test > or =20% of both beef and dairy cattle >24 months old routinely. Currently, however, GB serologically tests more cattle than required and the issue of reducing the level of testing has come under consideration. We developed a simulation model to determine the rate of spread of brucellosis under a variety of testing regimes. For dairy herds, we found that reducing the level of testing would have a major effect on the rate of spread of infection, should it be imported. For beef herds, reducing the level of testing would have much less effect. We also found that abortion notification is a very-important additional means of surveillance. As a result of our predictions, policy-makers decided not to reduce the level of testing and actively to promote abortion notification.

Vasoconstrictive effects of endothelin-1, endothelin-3, and urotensin II in isolated perfused human lungs and isolated human pulmonary arteries

BACKGROUND

Urotensin II (UII) has been identified as a ligand for the orphan receptor GPR14 through which it elicits potent vasoconstriction in humans and non-human primates. The pulmonary vasculature is particularly sensitive; human UII (hUII) exhibits a potency 28 times that of endothelin (ET)-1 in isolated pulmonary arteries obtained from cynomolgus monkeys. However, hUII induced vasoconstriction in isolated human intralobar pulmonary arteries is variable, possibly as a result of location dependent differences in receptor density or because it is only uncovered by disease dependent endothelial dysfunction.

METHODS

The vasoactivity of both hUII and gobi UII (gUII) in comparison with ET-1 and ET-3 was studied in isolated perfused lung preparations (n = 14) and isolated intralobar pulmonary arteries (n = 40, mean diameter 548 (27) microm) obtained from 17 men of mean (SE) age 67 (2) years and eight women of mean (SE) age 65 (3) years with a variety of vascular diseases.

RESULTS

ET-1 (10 pM-100 nM) and ET-3 (10 pM-30 nM) elicited vasoconstriction in the lung preparations, inducing comparable increases in pulmonary arterial pressure of 24.8 (4.5) mm Hg and 14.5 (4.9) mm Hg, respectively, at 30 nM (p = 0.13). Similarly, ET-1 (10 pM-300 nM) and ET-3 (10 pM-100 nM) caused marked vasoconstriction in isolated pulmonary arteries, inducing maximal changes in tension of 4.36 (0.26) mN/mm and 1.54 (0.44) mN/mm, respectively, generating -logEC(50) values of 7.67 (0.04) M and 8.08 (0.07) M, respectively (both p<0.05). However, neither hUII nor gUII (both 10 pM-1 micro M) had any vasoactive effect in either preparation.

CONCLUSION

UII does not induce vasoconstriction in isolated human pulmonary arterial or lung preparations and is therefore unlikely to be involved in the control of pulmonary vascular tone.

A quantitative risk assessment for the importation of brucellosis-infected breeding cattle into Great Britain from selected European countries

Great Britain (GB) has been "Officially Brucellosis Free" (OBF) since 1991; because this disease has both public-health and international-trade implications, it is in the country's interest to maintain this freedom. A quantitative risk-assessment model was developed to determine the annual risk of importing brucellosis-infected breeding cattle into GB from Northern Ireland and the Republic of Ireland. (These countries exported the largest number of cattle into GB and were not brucellosis free during the development of the assessment in 2000.) We predicted that we can expect to import brucellosis from Northern Ireland every 2.63 years (1.89, 4.17) and from the Republic of Ireland, every 3.23 years (2.13, 5.88). The estimates of risk are sensitive to the assumed proportion of animals missed during routine surveillance that originate from OBF herds and the uncertainty associated with the surveillance test sensitivities. As a result of the assessment, the Department for Environment, Food and Rural Affairs (Defra) introduced post-calving testing for all cattle imported into British herds.

Phosphorus in periphyton mats provides the best metric for detecting low-level P enrichment in an oligotrophic wetland

Growing concern over the ecological consequence of phosphorus (P) enrichment in freshwater wetlands has elicited considerable debate over the concentration of water column P associated with eutrophication. In the oligotrophic Everglades, the displacement of native communities by enriched ones is widespread and has occurred at sites experiencing only minimal elevations in P input. To help define regulatory criteria for P inputs to the Everglades, we constructed an experiment that mimics P input to the natural system by continuously delivering P at concentrations elevated 5, 15 and 30 microgl(-1) above ambient to 100-m long flow-through channels. We compared patterns of P accumulation in the water, periphyton, detritus and soils among the channel treatments and also along a 16 km transect from an enriched canal that inflows to the interior of the same marsh. Water column TP and SRP were unrelated to input TP concentration in both the experiment and the marsh transect. However, concentrations of TP in periphyton mats were significantly elevated at all levels of experimental enrichment and as far as 2 km downstream from water inputs into the marsh. Elevated periphyton TP was associated with significant loss of periphyton biomass. In oligotrophic wetlands, traditional measures of water column SRP and TP will substantially underestimate P loading because biotically incorporated P is displaced from the water column to benthic surfaces. Using periphyton TP as a metric of P enrichment is uncomplicated and analogous to pelagic TP assessments in lakes where most P is sequestered in phytoplankton.

Effects of Perinatal Exposure to Hypoxia upon the Pulmonary Circulation of the Adult Rat

The hypothesis on Fetal and Infant Origins of Adult Disease proposes that an altered in utero environment may impair fetal development and physiological function, increasing susceptibility to disease in adulthood. Previous studies demonstrated that reduced fetal growth predisposes to adult cardiovascular diseases. Maternal smoking and high altitude are also linked to reduced fetal growth and adult disease, and both cause fetal hypoxia. We therefore wanted to determine whether fetal hypoxia produces alterations in the adult pulmonary vasculature. Body and ventricular weight, pulmonary arterial compliance and vasoreactivity to potassium chloride (KCl), prostaglandin F2alpha (PGF2alpha), acetylcholine (ACh) and sodium nitroprusside (SNP) were studied in adult rats exposed to 10 % hypoxia throughout the perinatal period, compared to age-matched controls. Rats exposed to perinatal hypoxia had reduced body weight (199+/-15 vs. 294+/-10 g, P<0.001), elevated right ventricular weight (70.3+/-8.8 vs. 51.4+/-1.2 mg/100 g, P<0.05), elevated left ventricular weight (281+/-27 vs. 232+/-5 mg/100 g, P<0.05), reduced pulmonary arterial compliance (35.2+/-2.0 vs. 46.4+/-2.4 microm/mN, P<0.05) and reduced maximal pulmonary vasoconstriction to KCl (1.74+/-0.14 vs. 2.63+/-0.31 mN/mm, P<0.01), and PGF2(2alpha) (1.40+/-0.14 vs. 2.47+/-0.44 mN/mm, P<0.05). Perinatal exposure to hypoxia had a profound effect upon the adult pulmonary circulation, which could predispose to cardiopulmonary diseases in adulthood.

Effects of perinatal exposure to hypoxia upon the pulmonary circulation of the adult rat

The hypothesis on Fetal and Infant Origins of Adult Disease proposes that an altered in utero environment may impair fetal development and physiological function, increasing susceptibility to disease in adulthood. Previous studies demonstrated that reduced fetal growth predisposes to adult cardiovascular diseases. Maternal smoking and high altitude are also linked to reduced fetal growth and adult disease, and both cause fetal hypoxia. We therefore wanted to determine whether fetal hypoxia produces alterations in the adult pulmonary vasculature. Body and ventricular weight, pulmonary arterial compliance and vasoreactivity to potassium chloride (KCl), prostaglandin F2alpha (PGF2alpha), acetylcholine (ACh) and sodium nitroprusside (SNP) were studied in adult rats exposed to 10 % hypoxia throughout the perinatal period, compared to age-matched controls. Rats exposed to perinatal hypoxia had reduced body weight (199+/-15 vs. 294+/-10 g, P<0.001), elevated right ventricular weight (70.3+/-8.8 vs. 51.4+/-1.2 mg/100 g, P<0.05), elevated left ventricular weight (281+/-27 vs. 232+/-5 mg/100 g, P<0.05), reduced pulmonary arterial compliance (35.2+/-2.0 vs. 46.4+/-2.4 microm/mN, P<0.05) and reduced maximal pulmonary vasoconstriction to KCl (1.74+/-0.14 vs. 2.63+/-0.31 mN/mm, P<0.01), and PGF2(2alpha) (1.40+/-0.14 vs. 2.47+/-0.44 mN/mm, P<0.05). Perinatal exposure to hypoxia had a profound effect upon the adult pulmonary circulation, which could predispose to cardiopulmonary diseases in adulthood.

Testosterone inhibits the prostaglandin F2alpha-mediated increase in intracellular calcium in A7r5 aortic smooth muscle cells: evidence of an antagonistic action upon store-operated calcium channels

Testosterone-induced vasodilatation is proposed to contribute to the beneficial effects associated with testosterone replacement therapy in men with cardiovascular disease, and is postulated to occur via either direct calcium channel blockade, or through potassium channel activation via increased production of cyclic nucleotides. We utilised flow cytometry to investigate whether testosterone inhibits the increase in cellular fluorescence induced by prostaglandin F(2alpha) in A7r5 smooth muscle cells loaded with the calcium fluorescent probe indo-1-AM, and to study the cellular mechanisms involved. Two-minute incubation with testosterone (1 microM) significantly inhibited the change in cellular fluorescence in response to prostaglandin F(2alpha) (10 microM) (3.6+/-0.6 vs 7.6+/-1.0 arbitrary units, P=0.001). The change in cellular fluorescence in response to prostaglandin F(2alpha) (10 microM) was also significantly attenuated in the absence of extracellular calcium (3.6+/-0.3 vs 15.6+/-0.7 arbitrary units, P=0.0000002), and by a 2-min incubation with the store-operated calcium channel blocker SK&F 96365 (50 microM) (4.7+/-0.8 vs 8.1+/-0.4 arbitrary units, P=0.003). The response was insensitive to similar incubation with the voltage-operated calcium channel blockers verapamil (10 microM) (12.6+/-1.2 vs 11.9+/-0.2 arbitrary units, P=0.7) or nifedipine (10 microM) (13.9+/-1.3 vs 13.3+/-0.5 arbitrary units, P=0.7). Forskolin (1 microM) and sodium nitroprusside (100 microM) significantly increased the cellular concentration of cyclic adenosine monophosphate and cyclic guanosine monophosphate respectively, but testosterone (100 nM-100 microM) had no effect. These data indicate that the increase in intracellular calcium in response to prostaglandin F(2alpha) occurs primarily via extracellular calcium entry through store-operated calcium channels. Testosterone inhibits the response, suggesting an antagonistic action upon these channels.

Testosterone as a protective factor against atherosclerosis--immunomodulation and influence upon plaque development and stability

Inflammation plays a central pathogenic role in the initiation and progression of coronary atheroma and its clinical consequences. Cytokines are the mediators of cellular inflammation and promote local inflammation in the arterial wall, which may lead to vascular smooth muscle apoptosis, degradation of the fibrin cap and plaque rupture. Platelet adhesion and thrombus formation then occur, resulting clinically in unstable angina or myocardial infarction. Recent studies have suggested that cytokines are pathogenic, contributing directly to the disease process. 'Anti-cytokine' therapy may, therefore, be of benefit in preventing or slowing the progression of cardiovascular disease. Both oestrogens and testosterone have been shown to have immune-modulating effects; testosterone in particular appears to suppress activation of pro-inflammatory cytokines. Men with low testosterone levels are at increased risk of coronary artery disease. An anti-inflammatory effect of normal physiological levels of sex hormones may, therefore, be important in atheroprotection. In this Article, we discuss some of the mechanisms involved in atherosclerotic coronary artery disease and the putative link between testosterone deficiency and atheroma formation. We present the hypothesis that the immune-modulating properties of testosterone may be important in inhibiting atheroma formation and progression to acute coronary syndrome.

EMMA--an eye movement measurement and analysis system

A system has been developed for stimulation, recording and analysis of a wide range of eye movements. Eye movements are stimulated with an LED bar or a video projector under the control of a PC. The eye movements are measured using a scleral reflection technique (IRIS instrument), and sampled and stored on a PC. A range of tests have been developed to measure saccadic and smooth pursuit eye movements. A variety of tools have been developed to assist in the analysis of the data. Several research studies have ably demonstrated the utility and versatility of the system.

Saccade sequences as markers for cerebral dysfunction following mild closed head injury

Diffuse axonal injury caused by mild closed head injury (CHI) is likely to affect the neural networks concerned with the planning and execution of sequences of memory-guided saccades. Thirty subjects with mild CHI and thirty controls were tested on 2- and 3-step sequences of memory-guided saccades. CHI subjects showed more directional errors, larger position errors, and hypermetria of primary saccades and final eye position. No deficits were seen in temporal accuracy (timing and rhythm). These results suggest that computerized tests of saccade sequences can provide sensitive markers of cerebral dysfunction after mild CHI.

Depression and anxiety in oncology: the oncologist's perspective

Depression and anxiety frequently occur in oncology patients and have a significant impact on patient quality of life, health care utilization, and even disease outcome. Depression and anxiety are eminently treatable, and therefore psychiatric assessment and appropriate intervention should form an integral component of management strategy in patients with cancer. It is essential that patients are recognized at an early stage, so that resources can be targeted effectively at those most at risk of developing psychiatric morbidity. Evaluation techniques that can identify signs or symptoms of depression and anxiety and can be incorporated into the program of a busy oncology clinic or in the primary care setting are therefore needed. Diagnosis of depression and anxiety may be facilitated by using primary screening tools, such as the Hospital Anxiety and Depression Scale questionnaire, and by considering factors such as family psychiatric history, levels of family support, and degrees of pain suffered by the patient. In this article, the issues surrounding diagnosis of depression and anxiety in cancer patients and the benefits of early intervention are considered from the point of view of the oncologist.

Testosterone acts as a coronary vasodilator by a calcium antagonistic action

T acts as a vasodilator in vitro and in vivo. Supplemental T therapy in humans with angina improves symptoms and reduces objective measures of ischemia. In left anterior descending coronary arteries taken from adult male Wistar rats, T abolishes 100+/-4.2% of calcium-dependent contraction induced by potassium chloride, 82.3+/-6.1% of the mostly calcium-dependent contraction induced by prostaglandin-F-2-alpha, but only 45.3+/-3.4% of the contraction induced by phorbol-12,13-dibutyrate (PDBu) in the presence of extracellular calcium, and 54.5+/-4.5% of the contraction induced by PDBu in the absence of extracellular calcium. These findings suggest that T is primarily inhibiting the calcium-dependent elements of vascular contraction.

Gender differences in the vasomotor effects of different steroid hormones in rat pulmonary and coronary arteries

It is well recognised that oestrogens possess vasodilatory properties, and similar responses to testosterone have been demonstrated. However, vasomotor effects of other steroid hormones have not been well described. Direct comparisons of the relative vasoactivity of different steroid hormones in different vascular beds in male and female genders have not been made. Coronary and pulmonary arteries from adult Wistar rats were mounted in a wire myograph, loaded to 100 and 17 mmHg respectively, maximally pre-contracted with 1 x 10(-4) M prostaglandin-F-2-alpha, and dose response curves to 1 x 10(-6) to 1 x 10(-3) or 3 x 10(-3) M of 17 beta-oestradiol, testosterone, progesterone, and cortisol dissolved in water were constructed. Addition of each steroid hormone caused acute, dose dependent dilatation in coronary and pulmonary vessels. In coronary arteries the order of activity was testosterone > progesterone > 17 beta-oestradiol > cortisol, p < 0.001. In pulmonary arteries, the order of activity was progesterone > testosterone > cortisol > 17 beta-oestradiol, p < 0.001. Pulmonary arteries from male animals were more sensitive to the effects of testosterone than those from female animals, p = 0.003, whereas coronary arteries from female animals were more sensitive to the effects of 17 beta-oestradiol than those from male animals, p < 0.001. We have demonstrated significant differences in the in vitro vasomotor effects of different steroid hormones in two distinct vascular beds. Gender differences in vasomotor responses to steroid hormones may play a role in the aetiology of vasospastic diseases.

Dysfluency and involuntary movements: a new look at developmental stuttering

Studies using modern imaging techniques suggest that, in developmental stuttering, there is dysfunction within the cortical and subcortical areas of the motor control system wider than that pertaining to speech motor control alone. If this is the case, one might expect motor deficits extending beyond and unrelated to the production of speech in people who stutter. This study explored this proposal by investigating the presence and characteristics of involuntary movements accompanying stuttering. Sixteen adults with developmental stuttering and 16 controls matched for age and sex were audio-videotaped during 5 minutes of conversational speech and reading a passage of 350 words. Audio-data were examined for dysfluencies. Movements of the face, head and upper body considered involuntary and not part of normal facial expression or gesture and not part of the mechanics of speech were identified and described from muted video-data. Subjects who stuttered had a higher proportion of classic (within-word) dysfluencies accompanied by involuntary movements (IMs) than controls during speech (24.4% vs. 4.5%, p = .054) and reading (28.6% vs. 4.9%, p = .033). There was no difference in proportion of classic dysfluencies accompanied by IMs between speech and reading for either group. IMs were also seen in both groups during fluent speech, with a similar incidence during free speech (3.9% vs. 3.0%, NS) but a greater incidence in the subjects who stuttered during reading (2.4% vs. 0.8%, p = .03). In contrast, there was no difference between the two groups for IMs accompanying normal (between-word) dysfluencies. This suggests that classic and normal dysfluency and their accompanying IMs have different etiologies. The notion that stuttering and IMs are due to altered function in a motor control system wider than that of speech motor control alone is supported by a higher incidence of IMs in people who stutter during both classic dysfluencies and fluent speech.

Severe developmental prosopagnosia in a child with superior intellect

Developmental prosopagnosia, a lifelong inability to learn and recognize familiar faces, has rarely been reported, and there are even fewer cases that have been studied during childhood. Of the cases studied during childhood, significant "apperceptive" features to the face recognition defect have been noted. We had an opportunity to conduct extensive standard and experimental neuropsychological, psychophysiological, and neuroanatomical studies in a five-year-old child with severe developmental prosopagnosia. The subject was intellectually gifted (FSIQ = 130), but had a marked discrepancy between verbal and nonverbal abilities (VIQ = 140, PIQ = 110). Although some visual perceptual weaknesses were apparent, the subject's face recognition defect was found to cnform most closely to the "associative" type, and he did not have visual recognition deficits for any categories of nonunique entities. A novel finding was that the child's covert recognition of familiar faces based on an autonomic index was normal, suggesting that as in some adult-onset cases, the brain is capable of acquiring some information about familiar faces, even without conscious recognition. The child also had normal judgments of facial emotional expressions. Our report extends the understanding of the neuropsychological features of developmental prosopagnosia, and may help narrow the search for neuroanatomical correlates of this condition, which have yet to be identified.

In situ reverse transcription to detect the cbbL gene and visualize RuBisCO in chemoautotrophic nitrifying bacteria

AIMS

In situ methodologies targeting the cbbL gene were used to visualize cells of nitrifying bacteria. Both procaryotic in situ PCR (IS-PCR) and in situ reverse transcription (ISRT) protocols were employed to determine gene presence and expression, respectively.

METHODS AND RESULTS

Aged-oligotropic seawater samples were inoculated with microbial assemblages containing a mixture of actively growing nitrifying bacteria, starved nitrifying bacteria, and heterotrophic bacteria without cbbL. After the molecular manipulations, we found that while all the nitrifiers (healthy or starved) with the cbbL gene were detected by IS-PCR, only the actively growing autotrophic nitrifiers with detectable levels of carbon fixation and nitrification activity were detected by ISRT analysis.

CONCLUSION

These results show how IS-PCR and ISRT supplement each other, and their potential for the analysis of heterogeneous populations where an assortment of healthy and starved/dormant cells are expected.

The NADPH oxidase inhibitors iodonium diphenyl and cadmium sulphate inhibit hypoxic pulmonary vasoconstriction in isolated rat pulmonary arteries

Interest surrounds the role of an NADPH oxidase-like enzyme in hypoxic pulmonary vasoconstriction (HPV). We have studied the effects of the NADPH oxidase inhibitors iodonium diphenyl (ID) and cadmium sulphate (CdSO4) upon HPV of isolated rat pulmonary arteries (n = 73, internal diameter 545 +/- 23 microm). Vessels were preconstricted with prostaglandin F2alpha (PGF2alpha, 0.5 or 5 microM) prior to a hypoxic challenge. ID (10 or 50 microM), CdSO4 (100 microM) or vehicle (50 microl) was added for 30 min before re-exposure to PGF2alpha and hypoxia. ID and CdSO4 significantly inhibited HPV. In vessels preconstricted with 5 microM PGF2alpha, ID (10 and 50 microM) reduced HPV from 37.4 +/- 5.6 % to 9.67 +/- 4.4 % of the contractile response elicited by 80 mM KCl (P<0.05) and from 30.1 +/- 5.0 % to 0.63 +/- 0.6% 80 mM KCl response (P<0.01), respectively. CdSO4 (100 microM) reduced HPV from 29.4 +/-4.0 % to 17.1 +/- 2.2% 80 mM KCl response (P<0.05). In vessels preconstricted with 0.5 microM PGF2alpha, ID (10 and 50 microM) reduced HPV from 16.0 +/- 3.15% to 3.36 +/- 1.44 % 80 mM KCl response (P<0.01) and from 15.0 +/- 1.67 % to 2.82 +/- 1.40 % 80 mM KCl response (P<0.001), respectively. Constriction to PGF2alpha was potentiated by ID. ID and CdSO4, at concentrations previously shown to inhibit neutrophil NADPH oxidase, attenuate HPV in isolated rat pulmonary arteries. This suggests that an NADPH oxidase-like enzyme is involved in HPV and could act as the pulmonary oxygen sensor.