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Biomedical subjects

N Flynn

Publications and source records attributed to N Flynn.

At least 19 recordsLinked to original sources
PubMed2002

On modelling the impacts of phosphorus stripping at sewage works on in-stream phosphorus and macrophyte/epiphyte dynamics: a case study for the River Kennet.

A new model of in-stream phosphorus and macrophyte dynamics, 'The Kennet model', was applied to a reach of the River Kennet, southern England. The reach, which is 1.5 km long, is immediately downstream of Marlborough sewage treatment works, where phosphorus reduction by tertiary effluent treatment began in September 1997. The model is used to simulate the flow, water chemistry and macrophyte biomass within the reach, both before and after phosphorus removal from the effluent. Monte Carlo experiments coupled with a general sensitivity analysis indicate that the model offers a feasible explanation for the salient aspects of the system behaviour. Model simulations indicate that epiphyte smothering is an important limitation to macrophyte growth, and that higher stream and pore water soluble reactive phosphorus (SRP) concentrations allow the earlier onset of growth for the epiphytes and macrophytes, respectively. Higher flow conditions are shown to reduce the simulated peak epiphyte biomass; though at present, the effect of flow on the macrophyte biomass is unclear. Another simulation result suggests that phosphorus will not be released from the bed sediments in this reach following phosphorus removal from the effluent.

Biomass↗
PubMed2001

Hepatitis C in methadone maintenance patients: prevalence and public policy implications.

OBJECTIVE: This study measured the extent and examined implications of hepatitis C (HCV) infection in a methadone maintenance treatment (MMT) population. METHOD: Four hundred and sixty patients were tested for HCV-Ab, hepatic enzymes and bilirubin, HCV-RNA, and hepatitis B antibody. RESULTS: Overall, 87% of this population had evidence of HCV-Ab. Among drug injectors (IDU), 96% were HCV-Ab positive. Among a subset of Laotian opium-smoking patients prevalence was only 11%. Sixty-two percent of patients with HCV-Ab had detectable HCV-RNA. Only 41% had elevated hepatic enzymes, and 5% had elevated bilirubin levels. All age groups were equally infected. Systemic problems in screening and treating HCV in drug users were identified. CONCLUSION: HCV infection poses significant long-term health risks for this population. Harm reduction interventions aimed at reducing transmission of HCV and other needle-related infectious disease deserves more consideration.

Adult↗
PubMed2001

A comparison of bone remodelling around hydroxyapatite-coated, porous-coated and grit-blasted hip replacements retrieved at post-mortem.

We investigated the implant-bone interface around one design of femoral stem, proximally coated with either a plasma-sprayed porous coating (plain porous) or a hydroxyapatite porous coating (porous HA), or which had been grit-blasted (Interlok). Of 165 patients implanted with a Bimetric hip hemiarthroplasty (Biomet, Bridgend, UK) specimens were retrieved from 58 at post-mortem. We estimated ingrowth and attachment of bone to the surface of the implant in 21 of these, eight plain porous, seven porous HA and six Interlok, using image analysis and light morphometric techniques. The amount of HA coating was also quantified. There was significantly more ingrowth (p = 0.012) and attachment of bone (p < 0.05) to the porous HA surface (mean bone ingrowth 29.093 +/- 2.019%; mean bone attachment 37.287 +/- 2.489%) than to the plain porous surface (mean bone ingrowth 21.762 +/- 2.068%; mean bone attachment 18.9411 +/- 1.971%). There was no significant difference in attachment between the plain porous and Interlok surfaces. Bone grew more evenly over the surface of the HA coating whereas on the porous surface, bone ingrowth and attachment occurred more on the distal and medial parts of the coated surface. No significant differences in the volume of HA were found with the passage of time. This study shows that HA coating increases the amount of ingrowth and attachment of bone and leads to a more even distribution of bone over the surface of the implant. This may have implications in reducing stress shielding and limiting osteolysis induced by wear particles.

Aged↗
PubMed2000

Effect of highly active antiretroviral therapy on the incidence of HIV-related cytomegalovirus retinitis and retinal detachment.

Cytomegalovirus retinitis (CMVR) is the most common intraocular infection encountered in ophthalmic practices. To assess the impact of highly active antiretroviral therapy (HAART) on the incidence of CMVR and subsequent retinal detachments, a retrospective review of the HIV+ patients seen at a single university and community-based practice between 1992-1993 (group 1), before the advent of protease inhibitors, was compared with the data obtained from October 1996 to October 1997 (group 2) and October 1997-1998 (group 3), after the widespread use of HAART. The incidence of CMVR and retinal detachment rates for each group was calculated and compared. Twenty five (2.6%) of 974 HIV+ patients in group 1 developed CMVR. Of these, four patients developed retinal detachment (16%). Group 2 had a total of 1084 HIV+ patients, 18 (1.7%) of whom developed CMVR, which indicates a 35% decline of the incidence of CMV retinitis at our institution (p = 0.052, Odds ratio = 0.533, Confidence interval 0.28-1.01) and three patients (20%) developed retinal detachment. Only 1 patient (0.07%) of 1274 patients in group 3 developed CMVR, which represents a 99% reduction since 1993 (p = 0.0000000456). We conclude that the incidence of CMVR at this institution has decreased significantly with the recent use of HAART therapy. This effect may be related to the aggressive use of HAART and associated immune recovery in this population of AIDS patients. In this small series, however, the rate of retinal detachment appeared unchanged, but was only observed in those individuals who were not on HAART or who had just recently started.

AIDS-Related Opportunistic Infections↗
PubMed1999

Methamphetamine use and sexual and injection risk behaviors among out-of-treatment injection drug users.

Our primary objective was to examine the relationship between methamphetamine use and sexual risk-taking behaviors--number of sexual partners, frequency of sexual behaviors with regular and casual partners, trading money or drugs for sex, and condom use--among male and female out-of-treatment injection drug users (OTIDUs). As a risk group for human immunodeficiency virus (HIV) transmission, we also investigated injection behaviors by methamphetamine use. Data were collected from 1392 OTIDUs within the California counties of Fresno, Sacramento, and San Diego. Excluded from this cross-sectional survey were male OTIDUs engaging in sex with only or mostly men since 1978. In bivariate analyses, we found that male OTIDUs with a history of methamphetamine use had more sex partners and participated in more acts of anal insertive intercourse with casual partners and vaginal intercourse with regular and casual partners than male OTIDUs never using methamphetamines. In addition, a greater percentage of male OTIDUs using methamphetamines reported trading sex for money or drugs. Methamphetamine-using female OTIDUs participated in more acts of vaginal intercourse with regular male sex partners than female OTIDUs never using methamphetamines. By multivariate logistic regression, we found methamphetamine use related to consistent condom use among male OTIDUs and among male sex partners of female OTIDUs. Discriminant function analyses revealed that sexual risk taking could be differentiated by methamphetamine use among male OTIDUs. Methamphetamine use also correlated with using shared needles or syringes among male and female OTIDUs and was related to not always disinfecting used needles or syringes with bleach. Our findings suggest that methamphetamines may contribute to heterosexual HIV transmission.

Adolescent↗
PubMed1998

Analgesia following appendicectomy--the value of peritoneal bupivacaine.

PURPOSE: Peritoneal inflammation is an important feature in many patients presenting with appendicitis. The contribution of peritoneal nerve fibres to pain experienced after appendicectomy has received little attention. METHOD: In this prospective double blind randomized study a consecutive series of 60 patients undergoing appendicectomy for suspected appendicitis were enrolled. A dose of 1.5 mg.kg-1 bupivacaine 0.5% was used. Group one patients received the entire dose of bupivacaine subcutaneously. Group two patients received half the dose subcutaneously (s.c.) and half the dose to the peritoneum. Pain scores were assessed pre-operatively and at 30 min, 12 and 24 hr post-operatively using a visual analogue scale. Time to first analgesia and total analgesia requirements in the first 24 hr were recorded. RESULTS: The patients receiving the s.c. combined with peritoneal bupivacaine had a lower pain score 30 min post-operatively (32 +/- 2 vs 54 +/- 4; P < 0.0001), a longer time to first analgesia (248 +/- 20 vs 164 +/- 17 min; P = 0.002) as well as lower opioid (68 +/- 5 vs 100 +/- 7 mg; P = 0.0002) and non steroidal analgesic requirements (65 +/- 6 vs 96 +/- 6 mg; P = 0.007) in the first 24 hr post-operatively. CONCLUSION: A combination of s.c. and peritoneal infiltration with bupivacaine is superior to skin infiltration alone in the relief of pain post appendicectomy.

Adult↗
PubMed1998

A prospective randomized trial of intraoperative bupivacaine irrigation for management of shoulder-tip pain following laparoscopy.

BACKGROUND: Postoperative shoulder-tip pain (STP) frequently occurs following laparoscopic surgery. In an attempt to abrogate this complication we prospectively evaluated the efficacy of intraoperative irrigation of the diaphragm with bupivacaine. METHODS: One hundred and five consecutive patients undergoing laparoscopic surgery were prospectively randomized to treatment or control groups. Treatment group (B, n = 55) received irrigation with 10 mL 0.5% bupivacaine in 500 mL saline and control group (A, n = 50) received an equal volume of normal saline. Each dome of the diaphragm was irrigated with 250 mL of either solution at the end of surgery. Laparoscopic procedures performed included cholecystectomy (n = 63), Nissen fundoplication (n = 21), appendicectomy (n = 7), hernia repair (n = 4), and diagnostic laparoscopy (n = 10). Patients' anesthesia and perioperative analgesia were standardized. STP was recorded on a visual analogue pain scale (VAPS) in the recovery room immediately following surgery and at 4, 10, and 24 hours thereafter. RESULTS: The overall incidence of STP in patients undergoing laparoscopic procedures was approximately 24%. Twenty-one patients (42%) in the control group and 4 patients (7%) in the treatment group complained of shoulder pain during the recording period (P = 0.003). Mean STP scores as recorded on VAPS were significantly lower in the bupivacaine group than in the control group from 4 to 24 hours after surgery (P < 0.01). Postoperative analgesia requirements were also significantly reduced in those patients receiving bupivacaine irrigation (P < 0.04). CONCLUSION: Intraperitoneal irrigation with bupivacaine to both hemidiaphragms at the end of surgery significantly reduces both frequency and intensity of STP following laparoscopic procedures thus reducing patient morbidity.

Adolescent↗
PubMed1998

The attitudes of patients and health care personnel to rectal drug administration following day case surgery.

The use of suppositories has been examined following a recent case in which an anaesthetist was reported to the United Kingdom General Medical Council. This study examined the preference for routes of administration of post-operative analgesia. A semistructured interview with a written questionnaire was administered to 610 subjects (49 doctors; 62 nurses; 67 paramedical staff; 44 other hospital employees; 388 patients). Four hundred and fifty (74%) preferred the intravenous (i.v.) route, 24 (4%) preferred a suppository while 136 (22%) found either route acceptable. The i.v. route was most popular with young (98% under 20 years) females (79%) social class I subjects (90%), doctors (96%), nurses (95%), those who had never had a suppository (81%) and those who had ill effects following a previous suppository (95%). This result suggests that patients are more tolerant of suppositories than hospital staff but the majority prefer the i.v. route.

Administration, Rectal↗
PubMed1994

In vitro activity of readily available household materials against HIV-1: is bleach enough?

This report describes experiments assessing the effectiveness against HIV of potential disinfecting agents that are commonly available to IDU when they are sharing syringes. We exposed cell-free HIV, HIV-infected cells, and HIV-infected blood containing known quantities of HIV to household cleaning agents, alcohols, peroxide, and highly acidic materials for 1 min, in order to examine the effects of these materials on the infectivity of the HIV. Undiluted liquid laundry bleach and dilute liquid dish detergent reduced the number of culturable HIV to an undetectable level under the experimental conditions used. Diluted bleach was not completely effective. Other potential disinfecting agents, including ethanol, isopropyl alcohol, and hydrogen peroxide, were unable to disinfect high numbers of HIV-infected cells or infected blood. Liquid dish detergent warrants further study as a possible acceptable alternative to bleach. Our data provide support for recommendations to IDU that they disinfect shared syringes every time between users with full-strength liquid laundry bleach to reduce their risk of acquiring or transmitting HIV. When bleach is not available, liquid dish detergent or other available disinfecting agents such as rubbing alcohol, hydrogen peroxide, or high alcohol content beverages are more effective than water at disinfecting HIV, recognizing that these materials are less effective than bleach. Although these materials are effective, they should not be viewed as a substitute for decreased sharing of injection equipment by IDU, or increased availability of sterile needles and syringes.

1-Propanol↗
PubMed1992

Role of guanylate cyclase-cGMP systems in halothane-induced vasodilation in canine cerebral arteries.

The cellular mechanisms through which halothane dilates blood vessels remain largely unknown. The present studies were designed to determine the effects of 0.59 and 0.9 mM halothane (equivalent to 2.0% and 3.0%, respectively) on tissue cyclic guanosine 3,5-monophosphate (cGMP) level and guanylate cyclase enzyme activity in canine middle cerebral arteries. Rings of cerebral arteries preconstricted with 5-hydroxytryptamine (0.2 microM) were exposed for 15 min to low or high concentrations of halothane or for 5 min to sodium nitroprusside (50 microM). The vessels were instantaneously frozen by immersing them in liquid N2; they then were homogenized, and the tissue cGMP levels were determined using radioimmunoassay. Halothane produced 2.23 +/- 0.44- and 4.47 +/- 0.87-fold increases in tissue cGMP levels over control at 0.59 and 0.9 mM, respectively. Sodium nitroprusside, a nitrovasodilator, also increased the tissue cGMP level 7.80 +/- 1.36-fold over the control value. To understand better the mechanisms of halothane-induced increase of tissue cGMP level, the effects of this anesthetic agent on guanylate cyclase enzyme activity were examined. Halothane, unlike sodium nitroprusside, did not modulate the activity of the soluble guanylate cyclase enzyme. However, halothane (1.0 mM), like atrial natriuretic factor (5 microM), stimulated the particulate guanylate cyclase enzyme activity. LY-83583 (6-anilino-5,8-quinolinedione, 10 microM), an agent that inhibits soluble guanylate cyclase activity, significantly reduced the response of the vessels to calcium ionophore (A23187, 0.4 microM), an endothelium-dependent vasodilator, without producing a significant effect on halothane-induced vasodilation. These results suggest that halothane-induced vasodilation of cerebral blood vessels is partly mediated by an increase in tissue cGMP levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminoquinolines↗
PubMed1992

Seroepidemiology of viral infections among intravenous drug users in northern California.

Intravenous drug users are frequently exposed to parenterally transmitted viral infections, and these infections can spread to the general population through sexual activity. We investigated the prevalence of serologic markers for human immunodeficiency virus type 1 (HIV-1), human T-cell lymphotropic virus type I/II (HTLV-I/II), hepatitis B virus (HBV), and hepatitis C virus (HCV) in intravenous drug users and their sexual contacts. Of 585 drug users from northern California tested for these serologic markers, 72% were reactive for the antibody to HCV, 71% for the antibody to hepatitis B core antigen, 12% for HTLV-I/II antibodies, and 1% for the HIV-1 antibody. The prevalence of serologic markers for these four viruses correlated with the duration of intravenous drug use, the ethnic group, and the drug of choice. More than 85% of subjects infected with either HCV or HBV were coinfected with the other virus. All persons reactive to HTLV-I/II antibodies had antibodies for either HBV or HCV. Of 81 sexual contacts tested, 17% had evidence of HBV infection while only 6% were reactive for HTLV-I/II antibodies and 4% for the antibody to HCV. None of this group was infected with HIV-1. We conclude that HTLV-I/II and HCV are inefficiently transmitted to sexual contacts while HBV is spread more readily. Programs designed to discourage the sharing of drug paraphernalia, such as needle and syringe exchanges, should decrease the risk of parenterally spread viral infections in intravenous drug users and thus slow the spread of these infections to the general population.

Adult↗