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Biomedical subjects

R D Murray

Publications and source records attributed to R D Murray.

At least 73 records · Page 4Linked to original sources
PubMed1998

The Internet as a source for current patient information.

OBJECTIVE: The purpose of this study was to assess the quality of information a lay person could obtain from Internet (Net) sources regarding the treatment of childhood diarrhea. It also afforded an opportunity to evaluate the awareness and compliance of the general medical community with the American Academy of Pediatrics (AAP) guidelines on the management of acute diarrhea. METHODS: This was a prospective, open, observational, literature review performed with a computer workstation and medical library. The AAP practice parameter on the management of acute gastroenteritis in young children was selected as the current standard by which to judge all other documents. The Net was searched, and all documents retrievable from the first 300 references were evaluated for compliance with current recommendations on the management of diarrhea in children. RESULTS: Of 60 articles published by traditional medical sources, only 12 (20%) conformed to current AAP recommendations for treatment of children. The source of the information, even if from a major academic medical center, did not improve the likelihood of compliance. CONCLUSIONS: As demonstrated by information supplied on World Wide Web sites by traditional medical sources, recommendations for the treatment of acute diarrhea show a low percentage of concurrence with the AAP guidelines. Major medical institutions, schools, and hospitals need to devise ways to carefully monitor and establish quality control of what is being distributed from their home pages. Patients must be warned about the voluminous misinformation available on medical subjects on the Net.

Acute Disease↗
PubMed1998

Heterogeneity of diagnoses presenting as cyclic vomiting.

OBJECTIVE: To establish the diagnostic profile in children who present with cyclic vomiting. METHODS: We studied 225 children < 18 years of age who presented to our pediatric gastroenterology service from 1986 to 1997 with at least three discrete episodes of vomiting between which they were well. To determine the diagnoses in those presenting with a pattern of cyclic vomiting, the results of diagnostic testing and responses to various treatments were obtained from a combination of chart review and structured telephone interviews. RESULTS: The largest diagnostic category included idiopathic cyclic vomiting syndrome (88%). Extraintestinal disorders (7%) and gastrointestinal disorders (5%) constituting the probable cause of vomiting were established in those having complete cessation of episodes after therapy. In 12%, serious surgical disorders of the gastrointestinal (malrotation), renal (acute hydronephrosis), and central nervous systems (neoplasm) were found. In 2%, serious endocrine (Addison's disease) and metabolic disorders (disorder of fatty acid oxidation) were found. Among those with idiopathic cyclic vomiting syndrome, 41% had associated disorders (gastroesophageal reflux and chronic sinusitis) that could contribute to the vomiting, but, based on a partial response to therapy, were not deemed to be the main cause. Altogether 49% had an identified disorder that probably caused or could contribute to the vomiting. CONCLUSIONS: The cyclic pattern of vomiting is a symptom complex that can be induced by heterogeneous disorders that either cause or contribute to the vomiting. Once the cyclic vomiting pattern is identified, systematic diagnostic testing is warranted to look for these underlying disorders.

Central Nervous System Diseases↗
PubMed1997

Cardioversion guided by transesophageal echocardiography: the ACUTE Pilot Study. A randomized, controlled trial. Assessment of Cardioversion Using Transesophageal Echocardiography.

BACKGROUND: Electrical cardioversion in patients with atrial fibrillation is associated with an increased risk for embolic stroke. Screening for atrial thrombi with transesophageal echocardiography (TEE) before cardioversion should, in many patients, safely permit cardioversion to be done earlier than would be possible with prolonged conventional, anticoagulation therapy. OBJECTIVE: To compare the feasibility and safety of TEE-guided early cardioversion with those of conventional management of cardioversion in patients with atrial fibrillation. DESIGN: Randomized, multicenter clinical trial. SETTING: 10 hospitals in the United States, Europe, and Australia. PATIENTS: 126 patients who had atrial fibrillation lasting longer than 2 days and were having electrical cardioversion. INTERVENTION: Conventional therapy or early, TEE-guided cardioversion with short-term anticoagulation therapy. OUTCOME MEASURES: Feasibility outcome variables were frequency of cardioversion and times to cardioversion and sinus rhythm. Safety outcomes were ischemic stroke, transient ischemic attack, systemic embolization, bleeding, and detected episodes of clinical hemodynamic instability occurring as long as 4 weeks after cardioversion. RESULTS: 62 patients were randomly assigned to receive TEE-guided cardioversion; TEE was done in 56 (90%) of these patients. Atrial thrombi were detected in 7 patients (13%) and led to the postponement of cardioversion. Cardioversion was successful in 38 of 45 patients (84%) who had early cardioversion. No embolization occurred with this strategy. Of the 64 patients receiving conventional therapy, 37 (58%) had cardioversion, which was successful in 28 patients (76%). One patient had a peripheral embolic event. The time to cardioversion was shorter in the TEE group (0.6 weeks [95% CI, 0.3 to 0.9 weeks] compared with 4.8 weeks [CI, 3.8 to 5.7 weeks]; P < 0.01). The incidence of clinical hemodynamic instability and bleeding complications tended to be greater in the conventional therapy group. CONCLUSIONS: These results suggest that TEE-guided cardioversion with short-term anticoagulation therapy is feasible and safe. The use of TEE may allow cardioversion to be done earlier, may decrease the risk for embolism associated with cardioversion, and may be associated with less clinical instability than conventional therapy. A large, multicenter study to confirm these findings is currently under way.

Aged↗
PubMed1997

Measurement of the rate of entry of intact colon-derived lactose into the circulation: a model for assessing gut uptake of molecules not endogenously synthesized.

BACKGROUND: Results of in vitro studies have documented colonic absorption of lactose in the newborn. A stable isotope model was developed for assessing the entry rate of intact lactose into the portal circulation in newborn piglets. METHODS: In experiment 1, unlabeled and [D-1-(13C)]-lactose were infused into two separate mesenteric veins, and in experiment 2, labeled lactose was infused into a mesenteric vein and unlabeled lactose was infused into the colon. The 13C-enrichment of plasma lactose was assessed by high performance liquid chromatography gas chromatography combined with mass spectrometry. RESULTS: The isotopic estimate of the mesenteric venous infusion rate of lactose was 91% of the theoretical. In the second experiment 13% of the unlabeled lactose infused into the colon reached the portal circulation. CONCLUSIONS: The current study provides the first, direct, in vivo confirmation of colon absorption of intact lactose. The tracer model could be used to evaluate intestinal or colonic absorption of other organic compounds not endogenously synthesized, including vitamins or drugs.

Animals↗
PubMed1997

Technical note: pig model for studying nutrient assimilation by the intestine and colon.

We have developed a system for chronically catheterizing 10- to 25-d-old pigs that permits stable isotope tracer studies of intestinal or colonic assimilation of nutrients. This model also can be used to ensure constant enteral feeding or to assess the rate of entry into the terminal ileum of carbohydrates, fats, and amino acids. A plastic cannula with a luminal flange can be surgically placed in the stomach for tracer studies of sugar digestion or for controlled infusion of any formula diet. A similar cannula can be placed in the cecum for infusion of tracer and(or) substrates for studies of fermentation. The cannula has been machined so that a washer and nut can be threaded onto it, allowing the entire apparatus to be fixed to the abdominal wall. The distal end protruding above the skin was tapered to fit standard i.v. extension tubing. A carotid arterial catheter was used to sample substrates for isotopic enrichment measurements.

Amino Acids↗
PubMed1996

Epidemiology of lameness in dairy cattle: the influence of cubicles and indoor and outdoor walking surfaces.

A survey of cubicles and indoor and outdoor walking surfaces on 37 farms served by four veterinary practices in Somerset, Cheshire, Wirral and west. Wales was carried out in 1989 to 1991. A study of the space requirements of Friesian/Holstein cows at pasture showed that they required approximately 240 cm x 120 cm lying space and a further 60 cm lunging space for rising. By these standards, 87 per cent of the cubicles were too short and 50 per cent were too wide or too narrow. Over 1500 observations on cows lying down, rising and standing indicated that only 12 per cent of the cubicles permitted real freedom of movement; 91 per cent of top partition rails were judged to be too low and 70 per cent of bottom rails too low or too high. In addition, the kerb was very high in 76 per cent of the cubicles. As a result, 10 per cent of cows appeared moderately or severely restricted when lying down, 33 per cent when rising and 55 per cent when standing. Over 2000 cubicle beds were also studied; 75 per cent had a concrete base and of those, 63 per cent were judged to have too little bedding and 11 per cent next to none. Higher incidences and prevalences of lameness were associated with limited borrowing space (P < 0.01) low bottom rails (P < 0.05), high kerbs (P < 0.05) and inadequate bedding (P < 0.01). Of 3190 walking surfaces, only 25 per cent were classified as satisfactory in the first winter and 34 per cent in the second. In general, surfaces in silage bays were too rough and those in other sites were too smooth. The farms with the smoothest indoor walking surfaces had a significantly higher incidence of lameness (P < 0.01). Of 3335 outdoor walking surfaces only 25 per cent were classified as satisfactory, and 70 per cent were too rough. The incidence of lameness was not significantly related to these findings.

Animals↗
PubMed1996

Reduced conception rates in dairy cattle associated with serological evidence of Leptospira interrogans serovar hardjo infection.

Fertility data from 673 cows in five dairy herds with a moderate to high seroprevalence of microscopic agglutination titres (MAT) of > or = 1:10 against Leptospira interrogans serovar hardjo were collated to assess the relationship between pregnancy rates and antibody titres to serovar hardjo. A significant proportion of failures of conception (10 to 13 per cent, P < 0.001) were associated with MATs of 1:10 to 1:100; the overall pregnancy rate of the seronegative cows was 28.5 per cent higher (P < 0.001) than that of the cows with MATs of > or = 1:100. First service pregnancy rates showed a similar trend but the differences were significant (P < 0.05) only in cows with antibody titres > or = 1:30. An assessment of other possible risk factors for reduced pregnancy rates, such as lactation number and calving to first service interval, had no effect on the statistical results of the study or its conclusions.

Animals↗
PubMed1996

Epidemiology of lameness in dairy cattle: description and analysis of foot lesions.

Information from 37 dairy farms, in four regions of England and Wales provided data on 8991 lesions and the preventive trimming of 4837 cows' feet. Of the total of 13,828 forms returned, veterinary surgeons treated 32 per cent and farmers or stockmen 46 per cent. Of the 8645 lesions associated with episodes of lameness, lesions in the hindlimbs accounted for 92 per cent, of which 65 per cent were in the outer claw, 20 per cent in the skin and 14 per cent in the inner claw. Sole ulcers (40 per cent) and white line lesions (29 per cent) were the predominant diseases of horn, and digital dermatitis (40 per cent) was the most common disease of the skin. Subjective assessments showed that sandcrack, penetration of the sole by foreign bodies and interdigital necrobacillosis were associated with the most severe cases of lameness. There was a significant seasonal effect in the reporting of lesions.

Animals↗
PubMed1996

Incidence and prevalence of lameness in dairy cattle.

A survey was made of 37 dairy farms in Wirral, mid-Cheshire, mid-Somerset and Dyfed, Wales, to assess the incidence and prevalence of lameness in the cows between May 1989 and September 1991. The incidence was obtained from records made whenever a cow was examined for lameness or received preventive foot-trimming. The mean annual incidence was 54.6 new cases per 100 cows with a range from 10.7 to 170.1 and the mean values during summer and winter were 22.9 and 31.7, respectively. The prevalence of lameness was measured by regular visits at which locomotion was scored on a scale of 1 to 5, and the prevalence of lameness was calculated for each visit as the proportion of cows with scores of 3 or more. The mean annual prevalence over the whole period was 20.6 per cent with a range from 2.0 to 53.9 per cent for the 37 farms. The mean prevalences during summer and winter were 18.6 and 25.0 per cent, respectively. The prevalence measured at a single visit in midsummer or midwinter was significantly correlated with the mean prevalence over the whole corresponding period and may be useful as an assessment of the extent of lameness in a herd and the efficacy of control measures. There was evidence that training farmers to recognise early cases of lameness and request veterinary treatment resulted in a marked reduction in the duration of cases of lameness.

Animals↗
PubMed1996

Reproductive performance of dairy herds infected with Leptospira interrogans serovar hardjo relative to the year of diagnosis.

To assess the impact of Leptospira interrogans serovar hardjo infection on the reproductive performance of nine dairy herds with evidence of infection, forty years' fertility data were analysed relative to the year of first diagnosis. Fifty per cent of various fertility variables had their lowest values only in the year of diagnosis. Culling rates were highest during the year of diagnosis in five of the herds, and were above 22 per cent in five of nine (55-6 per cent) of the diagnosis years considered compared with seven (22-6 per cent) of the 31 non-diagnosis years. An assessment of the fertility status of the herds by means of a formula with incorporated the first service conception rate, the number of services per conception for cows conceiving, the calving to conception interval and the culling rate, revealed low reproductive performance during the year of diagnosis in six of the nine herds. Abortion rates were highest in four of the herds during the year of diagnosis, and these included the herds in which the fertility status was not lowest. It was concluded that L. interrogans serovar hardjo affected reproductive adversely by causing both abortions and low fertility, but that the effect was temporary.

Abortion, Veterinary↗
PubMed1996

Integrated backscatter for quantification of left atrial spontaneous echo contrast.

OBJECTIVES: This study was designed to develop a quantitative method of spontaneous echo contrast (SEC) assessment using integrated backscatter and to compare integrated backscatter SEC measurement with independent qualitative grades of SEC and clinical and echocardiographic predictors of thromboembolism. BACKGROUND: Left atrial SEC refers to dynamic swirling smokelike echoes that are associated with low flow states and embolic events and have been graded qualitatively as mild or severe. METHODS: We performed transesophageal echocardiography in 43 patients and acquired digital integrated backscatter image sequences of the interatrial septum to internally calibrate the left ventricular cavity and left atrial cavity under different gain settings. Patients were independently assessed as having no, mild or severe SEC. We compared intensity of integrated backscatter in the left atrial cavity relative to that in the left ventricular as well as to the independently assessed qualitative grades of SEC. Fourier analysis characterized the temporal variability of SEC. The integrated backscatter was compared with clinical and echocardiographic predictors of thromboembolism. RESULTS: The left atrial cavity integrated backscatter intensity of the mild SEC subgroup was 4.7 dB higher than that from the left ventricular cavity, and the left atrial intensity of the severe SEC subgroup was 12.5 dB higher than that from the left ventricular cavity. The left atrial cavity integrated backscatter intensity correlated well with the qualitative grade. Fourier transforms of SEC integrated backscatter sequences revealed a characteristic dominant low frequency/high amplitude spectrum, distinctive from no SEC. There was a close relationship between integrated backscatter values and atrial fibrillation, left atrial size, left atrial appendage flow velocities and thrombus. CONCLUSIONS: Integrated backscatter provides an objective quantitative measure of SEC that correlates well with qualitative grade and is closely associated with clinical and echocardiographic predictors of thromboembolism. The relationship between integrated backscatter measures and cardioembolic risk will be defined in future multicenter studies.

Aged↗
PubMed1996

Stereological estimation of the absolute number of glomeruli in the kidneys of lambs.

An association between the arrest of renal development and intra-uterine growth retardation (IUGR) has been demonstrated in human beings and it has been suggested that the same defect may occur in the kidneys of lambs affected by IUGR. Using design-based stereological methods, the physical disector and Cavalieri's principle, smaller absolute numbers of glomeruli were found in all six IUGR lambs studied with a low birthweight and in two of six control lambs studied with a normal birthweight than in other lambs with a normal birthweight. There was no difference in absolute numbers of glomeruli between twin births and singletons. The absolute numbers of glomeruli in three stillborn lambs were distributed among results obtained from the normal and IUGR lambs in accordance with their individual bodyweights. IUGR had a profound detrimental effect on the renal development of the lambs.

Abortion, Veterinary↗
PubMed1996

Presence of antigen and antibodies in serum and genital discharges of heifers after experimental intrauterine inoculation with Leptospira interrogans serovar hardjo.

The excretion of Leptospira interrogans serovar hardjo in cervico-vaginal mucus (CVM) or urine and the local and systemic immune responses to the organism were monitored in eight susceptible heifers after intrauterine inoculation while six similar heifers served as controls. All the heifers were inseminated at the subsequent oestrous periods. The overall percentage pregnancy rate (the number of pregnancies divided by the total number of inseminations) was lower in the infected heifers than in the controls though not significantly (33.3 v 50.0 per cent). Leptospires were detected, in either the urine or the CVM of six of the eight infected heifers during the study period of 15 weeks, either by direct immunofluorescence or dark ground microscopy; the bacteria did not grow in culture from any of the CVM samples. The control heifers remained free from evidence of infection. In the infected heifers, mean titres of at least 1:100 in a microscopic agglutination test were maintained for one to two weeks before declining to 1:10 to 1:30, whereas in serum IgG-ELISA tests (developed by using either protein or carbohydrate antigens), antibody titres of at least 1:100 were maintained throughout the study. During oestrous periods, IgA antibodies were detected more frequently in CVM with titres which were usually higher than the titres of IgG.

Agglutination Tests↗
PubMed1996

Presence of antigen and antibodies in serum and genital discharges of cows from dairy herds naturally infected with Leptospira interrogans serovar hardjo.

Samples of cervico-vaginal mucus from 163 bulling cows (group 1) and post calving discharges from 59 newly calved cows (group 2) in five dairy herds naturally infected with Leptospira interrogans serovar hardjo were examined for the presence of antigen and IgG and IgA antibodies by using two ELISA systems which were protein or carbohydrate based. Corresponding serum samples were examined for systemic immune responses by using a microscopic agglutination test (MAT) and IgG-ELISA tests. Antigen was detected by direct immunofluorescence in six of the 163 samples of cervico-vaginal mucus. Both IgG and IgA antibodies were detected by ELISA in the genital discharges with a prevalence much higher than that obtained by the MAT but lower than that observed with the serum IgG-ELISA. Combining both groups, none of the MAT-positive cattle was negative by serum-ELISA. By using the protein or carbohydrate fraction serum IgG-ELISA assays, respectively, 29 or 41 per cent of the MAT-negative cows were positive at a titre of at least 1:40. Similarly, eight or 23 samples (10 or 27 per cent) had titres of at least 1:20 in the genital discharge ELISA for IgG and IgA antibodies, respectively. The serum IgG-ELISA was the most efficient in detecting hardjo antibodies, but in group 2 the IgG- and IgA-ELISA of the post calving discharge proved to be equally effective.

Animals↗