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Biomedical subjects

H A Moss

Publications and source records attributed to H A Moss.

At least 19 recordsLinked to original sources
PubMed2003

The solitary pulmonary nodule.

The solitary pulmonary nodule will be found increasingly by the use of newer imaging techniques, including computed tomography (CT) screening. The aim must be to have an approach that avoids unnecessary surgery or biopsy with their attendant risks. Plain films characterisation, CT assessment, including densitometry and enhancement, and growth patterns are discussed and evaluated. The use of Bayes theorem to guide these assessment strategies is also described.

Contrast Media↗
PubMed2003

Pulmonary complications following bone marrow transplantation.

Pulmonary complications account for significant morbidity and mortality in patients following bone marrow transplants (BMT). They are distinct from other immunosuppressed patients in that there is a predictable course of immunosuppresion and therefore of likely pulmonary complications. This is important when interpreting abnormal radiology as the predictable time course will enable narrowing the differential diagnoses to certain pulmonary complications that characteristically occur at a particular time following BMT. Early recognition and correct treatment of the pulmonary complications should minimize the significant mortality and morbidity. This review aims to discuss the role of radiology in the diagnosis and management of pulmonary complications following BMT.

Bacterial Infections↗
PubMed2002

The use of carbon suspension as an adjunct to wire localisation of impalpable breast lesions.

AIM: To determine the accuracy and therapeutic success of localisation of impalpable breast lesions by hookwire with additional lesion marking with carbon suspension to mark screen detected abnormalities requiring surgical excision. MATERIALS AND METHODS: Retrospective review of all breast localisation procedures performed in our unit on women with a screen detected abnormality requiring excision over a 7 year period. RESULTS: One hundred and thirty eight women underwent breast localisation procedures. All of the mammographic abnormalities were excised at the initial surgical procedure. The benign to malignant ratio was 1:2. Pre-operative cytology was used to guide the extent of surgical excision, with clear margins in 70 of the 92 patients (75 percent) with malignancy. Twenty patients had further surgery: mastectomy in 7 and further local excision in 14. The localisation procedure was a therapeutic success in the local excision of malignancy in 73 of the 92 patients (79 percent) with malignancy. CONCLUSION: This method of localisation biopsy is an accurate technique for surgical excision of mammographically detected impalpable abnormalities. The surgeon is able to choose the site of surgical incision to give the best cosmetic result, the lesion is easier to identify at operation and the confidence that the abnormality has been excised is improved.

Aged↗
PubMed2000

A central venous catheter coated with benzalkonium chloride for the prevention of catheter-related microbial colonization.

In an attempt to overcome infections associated with central venous catheters, a new antiseptic central venous catheter coated with benzalkonium chloride on the internal and external surfaces has been developed and evaluated in a clinical trial. Patients (235) randomly received either a triple-lumen central venous catheter coated with benzalkonium chloride (117) or a polyurethane non-antiseptic catheter (118). The incidence of microbial colonization of both catheters and retained antiseptic activity of the benzalkonium chloride device following removal were determined. The benzalkonium chloride resulted in a significant reduction of the incidence of microbial colonization on both the internal and external catheter surfaces. The reduction in colonization was detected at both the intradermal (21 benzalkonium chloride catheters vs. 38 controls, P = 0.0016) and distal segments of the antiseptic-coated catheters. Following catheter removal retained activity was demonstrated in benzalkonium chloride catheters which had been in place for up to 12 days. No patients developed adverse reactions to the benzalkonium chloride catheters. The findings demonstrate that the benzalkonium chloride catheter significantly reduced the incidence of catheter-associated colonization.

Analysis of Variance↗
PubMed2000

Interferential therapy machines as possible vehicles for cross-infection.

Interferential therapy machines are used to apply alternating electric currents to patients for the treatment of various musculo-skeletal complaints. The potential for such machines to transfer skin microflora from one patient to another during treatment was investigated. The efficacy of the current disinfection procedure of the machines was also evaluated. In both the laboratory and clinical situation, interferential treatment, (which involves the direct application of electrodes to the skin surface) resulted in the transfer of micro-organisms from the skin of one subject to another. To decrease the likelihood of transmission of micro-organisms via interferential therapy machines, it is recommended that both the suction cups and sponges are disinfected with 70% isopropyl alcohol after the treatment of each patient. The use of disposable electrodes could also be considered.

Cross Infection↗
PubMed2000

A prospective clinical study to investigate the microbial contamination ofa needleless connector.

Needleless connectors, which allow direct access to intravascular catheters, are widely used in clinical practice. The benefits of these devices to healthcare workers are well documented; however, the potential risk of microbial contamination and associated infection is unclear. This clinical study evaluated microbial contamination rates for a needleless connector, Connecta Clave(R) (CC(R)), as compared to a conventional three-way tap, which was connected to the hubs of central venous catheters (CVC) immediately following insertion. Patients in the study group had CC(R) attached to the three-way taps, whereas the control group had standard entry port caps. On removal (up to 72 h) the connectors were studied for microbial contamination. There was no significant difference between the number of three-way taps contaminated on the internal surface with micro-organisms in the control group with entry port caps (19/132, 14%) compared to the group with CC(R) (18/105, 17%). Sixteen percent (27/173) of the CC(R) were contaminated with micro-organisms on the internal surfaces. The external surface of 33% (27/82) of the CC(R) silicone seals were contaminated after clinical use. Micro-organisms were also isolated from 9% (8/91) of the silicone seals after disinfection. The use of this needleless connector, compared to standard caps therefore does not appear to increase the risk of infection via the internal lumen of three-way taps.

Aged↗
PubMed2000

A novel serological test for the diagnosis of central venous catheter-associated sepsis.

OBJECTIVES: To determine the sensitivity and specificity of a novel antibody test for the diagnosis of intravascular catheter-related infections due to coagulase-negative staphylococci. METHODS: Sixty-seven patients diagnosed as having central venous catheter (CVC)-associated sepsis based on strict clinical criteria, including positive blood cultures, were compared to 67 patients with a CVC in situ who exhibited no evidence of sepsis. An ELISA serological test based on a novel short-chain lipoteichoic acid antigen isolated from coagulase-negative staphylococci (CNS) was used to determine the patient's serological response (IgG and IgM) to CVC sepsis caused by CNS. The specificity and sensitivity of the test was determined. RESULTS: There was a significant increase in the antibody levels (IgG and IgM) to the short-chain lipoteichoic acid in patients with CVC-associated staphylococcal sepsis as compared to the control patients. CONCLUSIONS: This new serological method may offer a useful diagnostic test for intravascular catheter infections caused by staphylococci.

Adolescent↗
PubMed1999

How reliable is modern breast imaging in differentiating benign from malignant breast lesions in the symptomatic population?

AIM: To assess the ability of mammography and ultrasound individually and in combination to predict whether a breast abnormality is benign or malignant in patients with symptomatic breast disease. MATERIALS AND METHODS: Patients included were those in whom histological confirmation of the abnormality following surgical excision was available. Mammographic and ultrasound appearances were prospectively classified using a four-point scale (1 = no significant lesion, 2 = benign lesion, 3 = possibly malignant, 4 = probably malignant). RESULTS: Histological confirmation following surgical excision was available in 559 patients, of which 303 were benign and 256 were malignant. The imaging classification was correlated with histology in these 559 lesions. In predicting final histology, the sensitivity and specificity of mammography alone were 78.9 and 82.7%, respectively, of ultrasound alone were 88.9 and 77.9%, respectively, and of mammography and ultrasound in combination were 94.2 and 67.9%, respectively. Only one patient had both a mammogram and ultrasound reported as normal (category 1 for both tests) in whom subsequent histology revealed a carcinoma (0.4% of all carcinomas). CONCLUSION: We found that the extensive use of ultrasound increases the cancer detection rate in this selected population by 14%.

Adult↗
PubMed1999

Subclavian and internal jugular veins at Doppler US: abnormal cardiac pulsatility and respiratory phasicity as a predictor of complete central occlusion.

In 21 consecutive patients, the authors analyzed changes in venous Doppler waveforms of damped or diminished cardiac pulsatility and respiratory phasicity. Each patient was suspected of having upper limb venous thrombosis, but thrombus was not visible at gray-scale ultrasonography (US) in the subclavian and brachiocephalic veins. US findings were compared with phlebographic findings. The results show that US can be used to establish the presence or absence of thrombosis in the distal portion of the brachiocephalic or subclavian veins, which are inaccessible to direct insonation.

Adult↗
PubMed1998

Use of pulsed field gel electrophoresis to determine the source of microbial contamination of central venous catheters.

Microorganisms detected in situ on the distal tip of central venous catheters (CVC) within 90 min of insertion were investigated using pulsed-field gel electrophoresis to analyse genomic fragments obtained with the SmaI restriction enzyme. Thirty patients received a triple lumen CVC, which was inserted directly through the skin using the Seldinger technique. In a further 30 patients a triple lumen CVC was inserted through a Swan sheath, thereby avoiding direct contact of the CVC with the skin. Staphylococci were isolated from the distal tips of the catheters in 6 patients (5 who had the CVC inserted directly through the skin and 1 who had the CVC inserted via a Swan sheath.) Twenty-three staphylococcal isolates were also isolated from the insertion equipment and the skin swabs surrounding the insertion site of these six patients. All the isolates were genotyped. In one of the patients the organisms isolated from the skin were identical to those on the CVC tip. In two further patients similar organisms were isolated from the insertion equipment and the patients' skin. These results, in addition to the reduced colonisation rates observed when catheters were introduced through a Swan sheath, support the hypothesis that microorganisms from the skin are impacted onto the CVC tip and the CVC insertion equipment at catheter insertion.

Bacteria↗
PubMed1997

Receptive and expressive language function of children with symptomatic HIV infection and relationship with disease parameters: a longitudinal 24-month follow-up study.

OBJECTIVES: To longitudinally assess the receptive and expressive language functioning of children with symptomatic HIV disease and to explore the relationship between immune status, computed tomography (CT) brain scan abnormalities, and language dysfunction over time. METHODS: Children with symptomatic HIV infection were administered an age-appropriate standardized comprehensive language test and general cognitive measure prior to starting antiretroviral therapy (n = 44) and again after 6 months (n = 29) and 24 months (n = 17). CD4 percentage and CT brain scans were also obtained at each evaluation. RESULTS: Expressive language was significantly more impaired than receptive language at the baseline, 6- and 24-month evaluations. No significant changes over time were found in receptive or expressive language from baseline to after 6 months of antiretroviral therapy, but despite treatment, language scores declined significantly between 6 and 24 months. Overall cognitive function, however, remained stable from baseline to 24 months. Age-adjusted CD4 percentage increased significantly over the initial 6 months, then remained stable. Overall CT brain scan severity ratings did not change significantly over 24 months. CONCLUSION: Expressive language was consistently more impaired than receptive language over 24 months, further supporting an earlier finding that expressive language was differentially affected by HIV in children with symptomatic disease. Both receptive and expressive language declined significantly after 24 months despite antiretroviral therapy, although overall cognitive function remained stable. Thus, functioning in some domains may be more vulnerable to the effects of HIV and global measures of cognitive ability may mask such differential changes in specific brain functions.

Adolescent↗
PubMed1997

Novel approach to investigate a source of microbial contamination of central venous catheters.

The potential route of contamination by skin microorganisms onto the distal tip of central venous catheters during insertion was investigated. Thirty patients undergoing cardiac surgery who required a central venous catheter (CVC) as part of their clinical management were studied. Following catheter placement, the device insertion equipment and the skin at the insertion site were sampled for microorganisms. The distal tips of the CVCs were also sampled in situ within 90 min post insertion. Bacteria were isolated from 20 of 30 (66%) CVC skin insertion sites, from 15 of 30 (50%) guidewires, and from five of 30 (16%) catheter distal tips in situ. These findings suggest that despite rigorous skin disinfection and strict aseptic technique, viable microorganisms are impacted during insertion onto the distal tip of the CVC, which may act as a subsequent nidus of infection.

Adult↗
PubMed1997

The potential for catheter microbial contamination from a needleless connector.

Needleless connectors have been widely introduced into clinical practice to allow the connection of syringes and luers to peripheral and central vascular catheters. The potential for microbial contamination of catheters via these devices is currently unclear. A recently introduced connector, the 'Connecta Clave', was assessed by various in-vitro methods. The 'Connecta Clave' is specifically devised to separate external components from the fluid pathway. The compression seals of 50 devices were contaminated with 1 x 10(4) cfu Staphylococcus epidermidis, disinfected with isopropanol, and fluid passed through. Only one device allowed organisms to pass through, despite this challenge, representing a contamination rate of 2%. In comparison, when 50 connectors were challenged with 20 cfu of S. epidermidis, no organisms passed through the device during use. In the clinical situation, after manipulation, < 16 cfu of skin organisms were found associated with the compression seal of the devices. It is, therefore, likely that the contamination rates in clinical practice will be extremely low. Three methods of disinfecting the compression seals and associated rims were also evaluated. A combination of alcohol chlorhexidine spray, followed by a 70% isopropanol swab, resulted in the most efficacious disinfection. The isopropanol swabs produced an adequate disinfection rate. The overall results suggest that by use of specially designed connectors, not only are needlestick injuries reduced, but the likelihood of microbial contamination of catheters via the internal route may also be diminished.

Catheters, Indwelling↗
PubMed1996

Neurobehavioral manifestations of symptomatic HIV-1 disease in children: can nutritional factors play a role?

Central nervous system (CNS) abnormalities are significant and frequent complications of human immunodeficiency virus (HIV-1) infection in infants and children. Although the predominant cause of neurological and neuropsychological abnormalities appears to be related to HIV infection of the CNS, other factors including malnutrition may also play a role. We retrospectively evaluated the association of change in body weight with changes in neurocognitive function, ventricular brain ratio, and cerebrospinal quinolinic acid levels in a small cohort of children (n=15; mean age 6.3 years) with symptomatic HIV-1 disease before and after 6 months of antiretroviral therapy with continuous intravenous infusion of zidovudine (ZVD). Significant increases in weight and neurocognitive function as well as decreases in ventricular brain ratio and cerebrospinal quinolinic acid levels were noted after therapy. Only the relation between increase in weight and decrease in ventricular brain ratio was statistically significant (P< .01); contrary to expectations, an increase in weight seemed to correlate with a decrease in neurocognitive function (NS). Another group of children treated at the same time with oral intermittent ZVD, but otherwise receiving the same care did not show the same magnitude of improvement in neurocognitive function. These results seem to suggest that general supportive and medical care as well as nutritional factors may only play a limited role in the neurocognitive improvements after antiretroviral therapy with continuous infusion ZVD. Our sample size was, however, small and the nutritional measure rather global; thus these findings have to be considered as very preliminary.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Impairment of expressive behavior in pediatric HIV-infected patients with evidence of CNS disease.

Rated observations of videotapes were made of 16 variables representing 5 behavioral domains (task orientation, positive social-emotional, motor skills, expressive speech, and activity) on a sample of 83 HIV-infected children. Comparisons were made on the rated behaviors between children classified as either encephalopathic or nonencephalopathic. Analyses were conducted separately for infants (M age = 1.80 years) and older children (M age = 5.15 years). The nonencephalopathic infants exhibited higher activity levels and were superior in motor and verbal skills and showed more social and emotional responsiveness than did the encephalopathic group. The older nonencephalopathic children functioned in a more adaptive and appropriate manner than did the encephalopathic children in all domains of behavior. Independently made Q-sort ratings of behaviors during developmental testing were highly correlated with conceptually congruent ratings of the videotaped behaviors.

AIDS Dementia Complex↗
PubMed1995

Relation between stage of disease and neurobehavioral measures in children with symptomatic HIV disease.

OBJECTIVE: To study the relationships between stage of HIV disease, reflected by CD4+ lymphocyte percentages and p24 antigen levels, and HIV-associated central nervous system (CNS) abnormalities, measured by computed tomography (CT) brain-scan ratings and neurobehavioral tests. DESIGN: Consecutive case series. SETTING: Government medical research center. PATIENTS: Eighty-six previously untreated children with symptomatic HIV-1 disease. RESULTS: CD4% measures correlated significantly with overall CT brain-scan severity ratings (r = -0.45; P < 0.001) as well as with its component parts (cortical atrophy, white matter abnormalities, and intracerebral calcifications); they were of comparable magnitude for vertically and transfusion-infected children. CD4% measures were also associated with the general level of cognitive function (r = 0.32; P < 0.005). Furthermore, patients with detectable serum p24 antigen levels (n = 39) had CT brain scans that were more abnormal than patients with undetectable p24 levels (n = 20; CT abnormality ratings of 21.3 versus 35.9; P < 0.02); similar differences were found for the cortical atrophy and calcification ratings. p24 levels also correlated with the overall CT brain-scan severity rating (r = 0.34; P < 0.01). CONCLUSIONS: Degree of CT brain-scan abnormality and level of cognitive dysfunction were significantly associated with the stage of HIV-1 disease, as reflected by either CD4 leukocyte measures or elevations of p24 antigen. The relation between the CT brain-scan lesions and markers of HIV disease (both CD4 and p24) suggest that these CNS abnormalities are most likely associated with HIV-1 infection, and further support the hypothesis that the interaction between systemic disease progression and CNS manifestations is continuous rather than discrete.

AIDS Dementia Complex↗