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Biomedical subjects

S Golding

Publications and source records attributed to S Golding.

At least 19 recordsLinked to original sources
PubMed2005

Targeted nNOS gene transfer into the cardiac vagus rapidly increases parasympathetic function in the pig.

Nitric oxide (NO) derived from neuronal nitric oxide synthase (nNOS) facilitates cardiac vagal neurotransmission and bradycardia in vitro. Here we provide evidence of rapid (within 9 h) protein expression and increased vagal responsiveness in vivo following targeted gene transfer of nNOS into the cardiac vagus of the pig. Right vagi were injected with vector encoding nNOS (Ad.nNOS) or saline, while left vagi received an injection of vector encoding enhanced green fluorescent protein (Ad.eGFP). Enhanced nNOS protein expression was detected exclusively in the right vagus nerve, with no evidence of iNOS expression. This was associated with increased baroreflex sensitivity and greater heart rate responsiveness to right vagal stimulation. In contrast, responsiveness of left vagi, or sham-injected right vagi remained constant over the same time period. Basal heart rate was unchanged following gene transfer, suggesting no change in vagal tone. These results support the pre-/post-ganglionic synapse as a site for NO-mediated facilitation of vagal bradycardia in the pig. In addition they demonstrate in vivo that functional gene expression induced with adenoviral vectors occurs earlier than first thought, and may therefore, provide a novel intervention to acutely modulate the neural control of cardiac excitability.

Animals↗
PubMed2004

Impaired regulation of neuronal nitric oxide synthase and heart rate during exercise in mice lacking one nNOS allele.

We tested the hypothesis that a single allele deletion of neuronal nitric oxide synthase (nNOS) would impair the neural control of heart rate following physical training, and that this phenotype could be restored following targeted gene transfer of nNOS. Voluntary wheel-running (+EX) in heterozygous nNOS knockout mice (nNOS(+/-), +EX; n= 52; peak performance 9.1 +/- 1.8 km day(-1)) was undertaken and compared to wild-type mice (n= 38; 9.5 +/- 0.8 km day(-1)). In anaesthetized wild-type mice, exercise increased phenylephrine-induced bradycardia by 67% (measured as heart rate change, in beats per minute, divided by the change in arterial blood pressure, in mmHg) or pulse interval response to phenylephrine by 52% (measured as interbeat interval change, in milliseconds, divided by the change in blood pressure). Heart rate changes or interbeat interval changes in response to right vagal nerve stimulation were also enhanced by exercise in wild-type atria (P < 0.05), whereas both in vivo and in vitro responses to exercise were absent in nNOS(+/-) mice. nNOS inhibition attenuated heart rate responses to vagal nerve stimulation in all atria (P < 0.05) and normalized the responses in wild-type, +EX with respect to wild-type with no exercise (-EX) atria. Atrial nNOS mRNA and protein were increased in wild-type, +EX compared to wild-type, -EX (P < 0.05), although exercise failed to have any effect in nNOS(+/-) atria. In vivo nNOS gene transfer using adenoviruses targeted to atrial ganglia enhanced choline acetyltransferase-nNOS co-localization (P < 0.05) and increased phenylephrine-induced bradycardia in vivo and heart rate responses to vagal nerve stimulation in vitro compared to gene transfer of enhanced green fluorescent protein (eGFP, P < 0.01). This difference was abolished by nNOS inhibition (P < 0.05). In conclusion, genomic regulation of NO bioavailability from nNOS in cardiac autonomic ganglia in response to training is dependent on both alleles of the gene. Although basal expression of nNOS is normal, polymorphisms of nNOS may interfere with neural regulation of heart rate following training. Targeted gene transfer of nNOS can restore this impairment.

Alleles↗
PubMed2004

Community pharmacy treatment of minor ailments in refugees.

OBJECTIVE: To evaluate a scheme offering pharmacy referrals for minor ailments in a refugee community. To determine if minor ailments could be managed by pharmacists offering over-the-counter (OTC) medication, free of charge, to refugees exempt from prescription charges. DESIGN: Refugees presenting with minor illnesses were offered a voucher. This voucher could be taken to the pharmacist, who, after a consultation, could exchange the voucher for appropriate OTC medication. SETTING: A refugee community in south London. OUTCOME MEASURES: The presenting minor ailment and corresponding medication as recorded by the pharmacist. RESULTS: A total of 200 vouchers were distributed to 184 refugees over a 5-month period resulting in the dispensing of 264 items. The five most frequent minor ailments were: upper respiratory tract infections (37%), headache (14%), musculo-skeletal pains (7%), allergy including hay fever (6%), indigestion (6%). The five most frequently dispensed items were: paracetamol (28%), sudafed (16%), ibuprofen (11%), aspirin (10%) and simple linctus (8%). Only two clients were referred directly to the GP and two advised to attend if symptoms persisted. CONCLUSIONS: Minor ailment schemes elsewhere have demonstrated the potential to divert about one-third of patients with minor illnesses out of general practice and to care in the pharmacy. Such a scheme is being widely adopted in Scotland this year. Our results are the first to demonstrate the feasibility and acceptability of such a scheme in the refugee community.

Community Pharmacy Services↗
PubMed2002

Prescribing indicators and their use by primary care groups to influence prescribing.

OBJECTIVE: To examine the prescribing incentive schemes used by primary care groups (PCGs); to determine the prescribing indicators used under these schemes; and to assess whether the schemes were seeking to improve the quality of prescribing as well as controlling prescribing costs. DESIGN: Cross-sectional survey. SETTING: A total of 145 PCGs in the London and South-East NHS regions. PARTICIPANTS: Prescribing advisers in each PCG. METHODS: Descriptions of the prescribing indicators monitored by each PCG were obtained from a questionnaire survey of PCGs at the end of the 1999-2000 financial year. Financial information on prescribing and details about the implementation of prescribing incentive schemes for this period became available 6 months later and were obtained by a further questionnaire, follow-up telephone and E-mail surveys. OUTCOME MEASURES: Prescribing indicators, prescribing budgets and spend. RESULTS: One hundred and twenty-one out of 145 (83%) PCGs replied to the questionnaires about prescribing indicators and 129 out of 145 (89%) replied with details about their prescribing costs. The most frequently monitored prescribing indicator was generic prescribing, used by 106 out of 121 (88%) PCGs. The most frequently used clinical areas for prescribing indicators were antibiotics (76% of PCGs), gastro-intestinal prescribing (68%), non-steroidal anti-inflammatories (37%) and cardiovascular prescribing (32%). Seventy-six (63%) schemes also used non-prescribing analysis & cost (PACT) based data for their incentive schemes such as information from prescribing audits and reviews of repeat prescribing protocols. Only 33 (23%) had reached agreement with their practices enabling all prescribing indicator information to be disseminated on a named basis to allow practices to examine each others' prescribing data. CONCLUSIONS: Prescribing incentive schemes usually include targets for improvements in prescribing quality as well as cost. PACT-based data were used for cost control and quality improvement but non-PACT data were almost entirely used to promote prescribing quality improvements. The validity of non-PACT data was questioned as was the choice of some indicators that appeared to have been selected without full consideration of current expert opinion. Further work is needed on which indicators are most likely to act as catalysts to prescribing change.

Drug Prescriptions↗
PubMed2002

A systematic review of the accuracy of ultrasound in the diagnosis of endometriosis.

OBJECTIVE: To evaluate transvaginal and transabdominal ultrasound scanning, with or without Doppler, as a diagnostic test for the accurate diagnosis of pelvic endometriosis. METHODS: The MEDLINE (1966-2001) and EMBASE (1980-2001) databases were searched for relevant studies, published in English. Only studies fulfilling predefined criteria were selected. An assessment of quality was made for each study, and data were then reanalyzed using likelihood ratios to determine the usefulness of the test. RESULTS: In total, 67 papers were identified using the search strategy, of which 17 described relevant studies. Of these, seven fulfilled the inclusion criteria. All seven related to the use of transvaginal gray-scale imaging in the diagnosis of ovarian endometriomata specifically, rather than endometriosis. The positive likelihood ratios ranged from 7.6 to 29.8, and the negative likelihood ratios ranged from 0.1 to 0.4. Confidence intervals were wide. One paper addressed the use of conventional color Doppler with ultrasound: the positive likelihood ratio was 1.2, with a negative likelihood ratio of 0.4. One paper assessed the use of color Doppler energy imaging, and showed a positive likelihood ratio of 33.5 and a negative likelihood ratio of 0.1. CONCLUSIONS: Transvaginal ultrasound appears to be a useful test both to make and to exclude the diagnosis of an ovarian endometrioma.

Endometriosis↗
PubMed2001

Intermittent hypoxia improves atrial tolerance to subsequent anoxia and reduces stress protein expression.

We tested the hypothesis that 21 days of intermittent hypoxia (IH) increases the tolerance of the spontaneously beating guinea-pig double atria preparation to acute in-vitro hypoxia, and reduces cardiac stress protein expression. A total of 28 guinea-pigs were divided into four groups: (i) IH; (ii) IH + in-vitro hypoxia (IH + IV); (iii) control (CON); (iv) control + in-vitro hypoxia (CON + IV). The IH animals were exposed to 8% O2/0.3% CO2 for 12 h day-1 for 21 days. Normoxic controls were exposed to room air for the same duration. Acute in-vitro hypoxia (20, 10, 5 and 0% O2 in 5% CO2) was introduced into the atrial preparation. Heat shock protein (Hsp) 70 and Hsp90 content were determined by Western blotting. Intermittent hypoxia groups demonstrated typical responses to chronic hypoxic exposure, characterized by significantly (P < 0.05) lower body weights, reduced growth rates and increased heart weight/body weight ratios. In the CON + IV group, in-vitro hypoxia reduced heart rate (20% O2, -30 +/- 8 beats min (-1); 10% O2, -34 +/- 8 beats min (-1); 5% O2, -37 +/- 9 beats min (-1) and 0% O2, -51 +/- 9* beats min (-1): *P < 0.05 vs. 20% O2). At 0% O2, the decrease in the rate response was significantly attenuated in the IH + IV (-30 +/- 8 beats min (-1); n=10) compared with the CON + IV (-51 +/- 9 beats min (-1); n=10). IH significantly reduced atrial Hsp70 and Hsp90 expression, however, levels of both proteins were unchanged in the ventricle. Furthermore, Hsp90 and to a lesser degree Hsp70 in the atria remained suppressed following in-vitro hypoxia in the IH group. Our results show that the increased resistance of the isolated atria to anoxia following IH may contribute to the concomitant reductions in basal and hypoxia-induced Hsp expression as the overall stress response is reduced.

Adaptation, Physiological↗
PubMed2001

Intermittent hypoxia modulates nNOS expression and heart rate response to sympathetic nerve stimulation.

Nitric oxide (NO) decreases norepinephrine (NE) release and the heart rate (HR) response to sympathetic nerve stimulation (SNS). We tested the hypothesis that the enhanced HR response to sympathetic activation following chronic intermittent hypoxia (IH) results from a peripheral modulation of pacemaking by NO. Isolated guinea pig double atrial/right stellate ganglion preparations were studied from animals that had been exposed to IH (n = 20) and control animals (n = 22). The HR response to SNS was significantly enhanced in the IH group compared with the controls. However, the increase in HR with cumulative doses (0.1--10 microM) of bath-applied NE was similar in both groups. Western blot analysis showed less neuronal NO synthase in the right atria from the IH group. In IH animals, the NO synthase inhibitor, N(omega)-nitro-L-arginine (L-NNA; 100 microM) did not alter the increased HR response to SNS, whereas in control animals L-NNA significantly increased the HR response to SNS; an effect that was reversed with excess L-arginine. In conclusion, the enhanced HR response to SNS after IH may be related to a decreased inhibitory action of NO on presynaptic NE release.

Animals↗
PubMed2001

Use of green fluorescent protein expressing Salmonella Stanley to investigate survival, spatial location, and control on alfalfa sprouts.

Laser scanning confocal microscopy (LSCM) was used to observe the interaction of Salmonella Stanley with alfalfa sprouts. The green fluorescent protein (gfp) gene was integrated into the chromosome of Salmonella Stanley for constitutive expression, thereby eliminating problems of plasmid stability and loss of signal. Alfalfa seeds were inoculated by immersion in a suspension of Salmonella Stanley (ca. 10(7) CFU/ml) for 5 min at 22 degrees C. Epifluorescence microscopy demonstrated the presence of target bacteria on the surface of sprouts. LSCM demonstrated bacteria present at a depth of 12 microm within intact sprout tissue. An initial population of ca. 10(4) CFU/g seed increased to 7.0 log CFU/g during a 24-h germination period and then decreased to 4.9 log CFU/g during a 144-h sprouting period. Populations of Salmonella Stanley on alfalfa seeds decreased from 5.2 to 4.1 log CFU/g and from 5.2 to 2.8 log CFU/g for seeds stored 60 days at 5 and 22 degrees C, respectively. The efficacy of 100, 200, 500, or 2,000 ppm chlorine in killing Salmonella Stanley associated with sprouts was determined. Treatment of sprouts in 2,000 ppm chlorine for 2 or 5 min caused a significant reduction in populations of Salmonella Stanley. Influence of storage on Salmonella Stanley populations was investigated by storing sprouts 4 days at 4 degrees C. The initial population (7.76 log CFU/g) of Salmonella Stanley on mature sprouts decreased (7.67 log CFU/g) only slightly. Cross-contamination during harvest was investigated by harvesting contaminated sprouts, then directly harvesting noncontaminated sprouts. This process resulted in the transfer of ca. 10(5) CFU/g Salmonella Stanley to the noncontaminated sprouts.

Bacterial Adhesion↗
PubMed2000

Pre-synaptic NO-cGMP pathway modulates vagal control of heart rate in isolated adult guinea pig atria.

The role of nitric oxide (NO) in the vagal modulation of heart rate (HR) is controversial. We tested the hypothesis that NO acts via a pre-synaptic, guanylyl cyclase (GC) dependent pathway. The effects of inhibiting NO synthase (NOS) and GC were evaluated in isolated atrial/right vagal nerve preparations from adult (550-750 g) and young (150-250 g) female guinea pigs. Levels of NOS protein were quantified in right atria using Western blotting and densitometry. The non-specific NOS inhibitor N- omega -nitro- L -arginine (L -NA, 100 microM, n=5) significantly reduced the negative chronotropic response to vagal nerve stimulation (VNS) at 3 and 5 Hz in the adult guinea pig. This effect was reversed with 1 m ML -arginine. Similar results were observed with the specific neuronal NOS inhibitor vinyl-N5-(1-imino-3-butenyl)- L -ornithine (L -VNIO, 100 microM, n=7). Inhibition of GC with 1H-(1,2,4)-oxadiazolo-(4, 3-a)-quinoxalin-1-one (ODQ, 10 microM, n=7) also significantly reduced the negative chronotropic response to VNS at 3 and 5 Hz in adult guinea pigs. Neither L -NA (n=6), L -VNIO (n=5) nor ODQ (n=6) changed the HR response to cumulative doses of carbamylcholine in adult guinea pig atria suggesting that the action of NO is pre-synaptic. The HR response to VNS was unaffected by L -NA (n=7) or ODQ (n=7) in young guinea pigs and Western blot analysis showed significantly lower levels of nNOS protein in right atria from young animals. These results suggest a pre-synaptic NO-cGMP pathway modulates cardiac cholinergic transmission, although this may depend on the developmental stage of the guinea pig.

Age Factors↗
PubMed2000

Peripheral pre-synaptic pathway reduces the heart rate response to sympathetic activation following exercise training: role of NO.

OBJECTIVES: We tested the hypothesis that the attenuated heart rate (HR) response to sympathetic activation following swim training in the guinea pig (Cavia porcellus) results from a peripheral modulation of pacemaking by nitric oxide (NO). METHODS: Nitric oxide synthase (NOS) inhibition on the increase in heart rate with sympathetic nerve stimulation (SNS) was investigated in the isolated guinea pig double atrial/right stellate ganglion preparation from exercise trained (6-weeks swimming, n=20) and sedentary animals (n=20). Western blot analysis for neuronal nitric oxide synthase (nNOS) was performed on the stellate ganglion from both groups. RESULTS: Relative to the control group, the exercise group demonstrated typical exercise adaptations of increased ventricular weight/body weight ratio, enhanced skeletal muscle citrate synthase activity and higher concentrations of [3H]ouabain binding sites in both skeletal and cardiac tissue (P<0.05). The increase in heart rate (bpm) with SNS significantly decreased in the exercise group (n=16) compared to the sedentary group (n=16) from 30+/-5 to 17+/-3 bpm at 1 Hz; 67+/-7 to 47+/-4 bpm at 3 Hz; 85+/-9 to 63+/-4 bpm at 5 Hz and 101+/-9 to 78+/-5 bpm at 7 Hz stimulation (P<0.05). The increase in heart rate with cumulative doses (0.1-10 microM) or a single dose (0.1 microM) of bath-applied norepinephrine expressed as the effective doses at which the HR response was 50% of the maximum response (EC50) were similar in both exercise (EC50 -6.08+/-0.16 M, n=8) and sedentary groups (EC50 -6.18+/-0.07 M, n=7). Trained animals had significantly more nNOS protein in left stellate ganglion compared to the sedentary group. In the exercise group, the non-isoform selective NOS inhibitor, N-omega nitro-L-arginine (L-NA, 100 microM) caused a small but significant increase in the heart rate response to SNS. However, the positive chronotropic response to sympathetic nerve stimulation remained significantly attenuated in the exercise group compared to the sedentary group during NOS inhibition (P<0.05). CONCLUSIONS: Our results indicate that there is a significant peripheral pre-synaptic component reducing the HR response to sympathetic activation following training, although NO does not play a dominant role in this response.

Animals↗
PubMed1999

Neutral amino acid transport in bovine articular chondrocytes.

1. The sodium-dependent amino acid transport systems responsible for proline, glycine and glutamine transport, together with the sodium-independent systems for leucine and tryptophan, have been investigated in isolated bovine chondrocytes by inhibition studies and ion replacement. Each system was characterized kinetically. 2. Transport via system A was identified using the system-specific analogue alpha-methylaminoisobutyric acid (MeAIB) as an inhibitor of proline, glycine and glutamine transport. 3. Uptake of proline, glycine and glutamine via system ASC was identified by inhibition with alanine or serine. 4. System Gly was identified by the inhibition of glycine transport with excess sarcosine (a substrate for system Gly) whilst systems A and ASC were inhibited. This system, having a very limited substrate specificity and tissue distribution, was also shown to be Na+ and Cl- dependent. Evidence for expression of the system Gly component GLYT-1 was obtained using the reverse transcriptase-polymerase chain reaction (RT-PCR). 5. System N, also of narrow substrate specificity and tissue distribution, was shown to be present in chondrocytes. Na+-dependent glutamine uptake was inhibited by high concentrations of histidine (a substrate of system N) in the presence of excess MeAIB and serine. 6. System L was identified using the system specific analogue 2-aminobicyclo(2,2, 1)heptane-2-carboxylic acid (BCH) and D-leucine as inhibitors of leucine and tryptophan transport. 7. The presence of system T was tested by using leucine, tryptophan and tyrosine inhibition. It was concluded that this system was absent in the chondrocyte. 8. Kinetic analysis showed the Na+-independent chondrocyte L system to have apparent affinities for leucine and tryptophan of 125 +/- 27 and 36 +/- 11 microM, respectively. 9. Transport of the essential amino acids leucine and tryptophan into bovine chondrocytes occurs only by the Na+-independent system L, but with a higher affinity than the conventional L system.

Amino Acids↗
PubMed1999

Magnetic resonance imaging versus radionuclide scintigraphy in screening for bone metastases.

AIM: To determine the frequency of isolated, asymptomatic metastases of the peripheral skeleton in patients with breast and prostate cancer. METHODS: A retrospective review was performed of staging skeletal scintigrams. Patients with hot spots in the peripheral skeleton in the absence of convincing evidence of metastatic disease in the axial skeleton were followed-up to determine the nature of the peripheral lesion(s) based on other imaging modalities, serial imaging or biopsy, and to determine if the lesion(s) had been symptomatic at the time of the scintigram. SUBJECTS: 200 patients with histologically proven carcinomas of the breast or prostate. RESULTS: Four patients (2%) had isolated metastatic involvement of the peripheral skeleton, and would, therefore, have been wrongly staged by a magnetic resonance 'marrow screen' of the axial skeleton. However, in three of these patients the lesions were painful, prompting diagnostic plain radiographs independent of the scintigraphic findings. Twelve patients (6%) had isolated scintigraphic abnormalities of the peripheral skeleton suggestive of metastatic disease but which on further investigation were shown to be benign lesions. CONCLUSION: A limited magnetic resonance (MR) 'marrow screen' confined to the axial skeleton would not result in any significant loss of accuracy in staging patients with breast and prostate carcinoma compared with skeletal scintigraphy. Given the proven increased sensitivity of MR over skeletal scintigraphy in the detection of bone metastases, and the additional information MR provides, it is likely to provide a more accurate basis for management.

Adult↗
PubMed1998

Expression of cation exchanger NHE and anion exchanger AE isoforms in primary human bone-derived osteoblasts.

The authors used isoform-specific antibodies against cation (NHE) and anion (AE) exchange isoforms in order to establish their specific expression and localization in dispersed human bone-derived cells. Immunocytochemical preparations of permeabilized osteoblasts probed with polyclonal antibodies were optically analysed by conventional immunofluorescence and con-focal laser scanning microscopy. These techniques demonstrated the abundant presence of epitopes of the cation exchangers NHE1 and NHE3 and the anion exchanger AE2 in these cells. The NHE1 and NHE3 isoform proteins were predominantly located in subplasmalemmal and nucleoplasmic vesicles. The AE2 isoform was densely localized to a subcellular location characteristic of the Golgi complex. The molecular identity of the AE and NHE isoforms was investigated by RT-PCR that confirmed the presence of NHE1 and NHE3 transcripts in addition to NHE4. RT-PCR and diagnostic restriction analysis of amplified AE cDNA established preferential AE2 expression. Since AE2 has been shown to act as a sulfate transporter at low pH, it is possible that it performs this function in the osteoblast Golgi complex where sulfation reactions occur post-translationally on numerous extracellular matrix macromolecules prior to secretion and mineralization. The Na(+)/H(+)exchanger proteins are regulated by mitogenic and non-mitogenic stimuli in the osseus environment and are involved in the large fluxes of ions and protons that necessarily occur during bone formation and resorption and thus play an important role in intracellular ion homeostasis in osteoblasts.

Alkaline Phosphatase↗
PubMed1997

Ceruloplasmin, transferrin and apotransferrin facilitate iron release from human liver cells.

The rate of iron release from HepG2 liver cells was increased not only by extracellular apotransferrin, but also by diferric transferrin, in a non-additive, concentration-dependent manner and to a similar magnitude. This suggests that rapid equilibration between receptor-mediated uptake and the release process determines net iron retention by the liver. Release was also accelerated by ceruloplasmin; most importantly, the effect of this protein was greatest when iron release was occurring rapidly, stimulated by apotransferrin, or under conditions of limited oxygen. Thus iron release involves both apotransferrin and ferrotransferrin, with ceruloplasmin playing a role in tissues with limited oxygen supply, as in the liver in vivo.

Apoproteins↗
PubMed1997

Characterization of the Na+, K(+)-ATPase in isolated bovine articular chondrocytes; molecular evidence for multiple alpha and beta isoforms.

We have used isoform-specific antibodies against the Na+, K(+)-ATPase alpha (alpha 1, alpha 2 and alpha 3) and beta (beta 1 and beta 2) subunit isoforms in order to establish their specific localization in isolated bovine articular chondrocytes. Immunoblotting confirmed the presence of the alpha 1 and alpha 3 isoforms, although alpha 1 expression was significantly greater than alpha 3 as assessed by immunofluorescence confocal laser scanning microscopy and PCR. A similar approach revealed the presence of the beta 1 and beta 2 isoforms in chondrocytes, although beta 2 immunostaining on the plasma membrane was more punctate than beta 1 which in contrast predominated in a subcellular compartment. The plasma membrane abundance of the Na+, K(+)-ATPase was found to be sensitive to the extracellular ionic concentration and long-term elevation of extracellular Na+ concentration significantly upregulated Na+, K(+)-ATPase density as measured by specific 3H-ouabain binding. Our observations suggest that the expression of alpha 3 and beta 2 is not restricted to excitable tissues as previously reported. The physiological relevance of alpha 3 expression in chondrocytes may be related to its low affinity for intracellular Na+ in an extracellular environment where Na+ concentration is unusually high (260-350 mM) compared to other cell types (140 mM). Glycoproteins and their branched carbohydrates have been implicated in cell recognition events, thus the beta 2 subunit glycoprotein may allow the chondrocyte to detect changes in its extracellular environment by physically interacting with components of the cellular cytoskeleton and matrix macromolecules.

Animals↗