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Biomedical subjects

J W Jones

Publications and source records attributed to J W Jones.

At least 19 recordsLinked to original sources
PubMed1995

Microbiological investigation of polyarthralgia.

Results of serological investigations on patients with joint pain, arthralgia or polyarthritis were analysed and this information was used to develop a diagnostic algorithm to ensure optimal utilisation of laboratory resources. Accordingly, all cases are now examined for parvovirus IgM, mycoplasma IgM and streptococcal antibodies. Further tests are undertaken by following the algorithm after obtaining supplementary information from a questionnaire. This approach is put forward as a preliminary standard which other laboratories may like to evaluate and develop according to local requirements.

Algorithms↗
PubMed1992

Usefulness of right ventricular indices in early diagnosis of cardiac tamponade.

Early diagnosis of postoperative cardiac tamponade is impeded by its clinical similarity to left ventricular failure. Moreover, the hemodynamic changes necessary to diagnose cardiac tamponade are detected by conventional monitoring technique only after clinical compromise. Early signs of cardiac tamponade and left ventricular failure were studied with emphasis on right ventricular function in anesthetized dogs. One group (n = 20) had cardiac tamponade produced by incrementally increasing pericardial pressure (2 to 20 mm Hg), and another group (n = 20) had acute left ventricular failure produced by successive ligation of the anterior descending coronary artery at the lower, middle, and upper thirds. Besides standard hemodynamic measurements, right ventricular function was examined with a rapid-response thermodilution catheter. During cardiac tamponade, cardiac output, right ventricular ejection fraction, right ventricular stroke volume, and right ventricular end-diastolic volume were significantly decreased from baseline values after a pericardial pressure of 8 mm Hg or more (p less than 0.05). Right atrial and pulmonary arterial pressures were not significantly elevated until 14 and 20 mm Hg of pericardial pressure, respectively. Although cardiac function in the left ventricular failure group was reduced after each ligation, right ventricular ejection fraction remained unchanged. This study suggests that right ventricular indices may facilitate earlier diagnosis of cardiac tamponade with greater accuracy.

Animals↗
PubMed1992

Spinal oxygenation, blood supply localization, cooling, and function with aortic clamping.

Similar to other methods of organ preservation, "spinoplegia" may protect the spinal cord from the effects of oxygen desaturation during aortic cross-clamping. In porcine experiments, spinal cord O2 saturation was studied during intraoperative localization of the blood supply to the spinal cord using hydrogen; division of arteries not supplying the spinal cord; aortic cross-clamping for 60 minutes; and 60 minutes after unclamping. In 5 animals, 120 mL of cold saline solution with lidocaine (100 mg/dL) was infused into the aorta during aortic cross-clamping. During sequential localization, O2 saturation dropped by 40.02% (standard deviation, 20.16%) for T-14 artery testing versus a decrease of 17.27% (standard deviation, 11.88%; p = 0.0075) for L-5 artery segment testing in the control animals and returned to baseline thereafter. During aortic cross-clamping maximal O2 desaturation was 5% of baseline (15.7%; p less than 0.0001), which improved slightly by 30 minutes after clamping (48% of baseline +/- 37.37%; p = 0.048 versus maximum) and then returned to baseline (97.1% of baseline +/- 41%) with unclamping; 5 minutes later, hyperoxygenation occurred with a progressive decline thereafter (68% of baseline +/- 29.3%; p = 0.025, 45 minutes after unclamping versus baseline). The decrease in spinal motor evoked potentials was significantly less (p less than 0.02) in the treated group. Intraoperative hydrogen testing in 8 patients was demonstrated to be safe. It accurately localized reattached arteries, and O2 saturation of the spinal cord fell by 56% (standard deviation, 29%; p = 0.0025) with aortic cross-clamping. We conclude that spinal cord ischemia occurs with aortic cross-clamping in both animals and humans.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

A study of coagulase-negative staphylococci with reference to slime production, adherence, antibiotic resistance patterns and clinical significance.

Two hundred and fifty-one strains of coagulase-negative staphylococci (CNS) isolated from patients in hospital and the community were investigated for slime production and adherence as indicators of pathogenicity. Staphylococcus epidermidis formed 68.5% (126) of the isolates of CNS from blood and central venous catheter (CVC) tips, of which 46.0% (58) were slime-positive and adherent. Clinically significant infections were associated with 55.2% (32) of the slime-positive adherent strains isolated and 11.1% (four) of slime-negative non-adherent strains of S. epidermidis. For other species of CNS isolated from blood and CVC tips 74.1% (43) were slime negative non-adherent and 18.6% (eight) of these were considered clinically significant isolates while none of the slime positive adherent strains were associated with a clinically significant infection. Slime production and adherence were not characteristic properties of CNS causing community-acquired urinary tract infection or colonizing the nasal mucosa. It is concluded that slime production and adherence had a limited role in the differentiation between clinically significant and contaminant strains isolated from blood cultures; however, the absence of slime and adherence in isolates of S. epidermidis suggested a lack of pathogenicity.

Bacterial Adhesion↗
PubMed1992

Lethal effects of ivermectin on Anopheles quadrimaculatus.

Female Anopheles quadrimaculatus adults were blood fed on 15 mixed breed dogs 4 h after the dogs were given oral dosages of ivermectin. Dogs were divided into 5 treatment groups of 3 dogs each, at 10, 500, 1,000, 2,500 micrograms/kg, and untreated. Additionally, An. quadrimaculatus were fed on lambskin-membranes containing blood drawn from one dog in each treatment group. Mosquitoes were allowed to feed on the dogs or the lambskin-membranes and were observed for death at 24 and 48 h post-feeding. Greater than 90% mortality was recorded in all ivermectin treatment groups except at the 24 h post-feeding period with the 10 micrograms/kg dog dose blood fed through the lambskin-membrane (65.4% mortality). The highest 2 dosages produced 100% mosquito mortality at 48 h post-feeding from either a dog or the in vitro system using a lambskin-membrane.

Animals↗
PubMed1992

Artificial blood substitutes.

Investigations directed toward the development of an effective artificial blood substitute are continuing as concerns remain regarding the safety and adequacy of the nation's blood supply. Perfluorochemical compounds, modified hemoglobin solutions, and microencapsulated hemoglobin represent the major areas of research. If a successful red cell substitute can be developed, many problems inherent in current blood transfusion practices could be alleviated, particularly in emergency situations.

Blood Substitutes↗
PubMed1991

Immunological assay of erythrocyte acetylcholinesterase.

An immunoassay for the quantitation of erythrocyte surface acetylcholinesterase is described; using a red cell suspension, bound mouse monoclonal acetylcholinesterase antibody is detected by an alkaline phosphatase conjugated rabbit anti mouse IgG. Extraction is not required. In addition, the activity of erythrocyte surface acetylcholinesterase using dithiobisnitrobenzoate to detect released thiocholine has been measured. The coefficient of variation for each method is 7%. Reference ranges have been established for healthy adults and cord blood.

Acetylcholinesterase↗
PubMed1991

Benefit from combining blood conservation measures in cardiac operations.

Conventional blood conservation techniques have been insufficient to decrease transfusion needs in increasingly complex cardiac operations. To evaluate combinations of conservation techniques, 300 patients were divided into three equal groups. Group 1 had intraoperative autotransfusion and return of mediastinal drainage for 4 hours postoperatively. Group 2 had these measures plus intraoperative plasmapheresis. These two groups were given a transfusion for a hematocrit of less than 0.21 on cardiopulmonary bypass. Group 3 was treated with the same measures as group 2 but did not receive transfusions while on pump unless the hematocrit decreased to less than 0.15. The percentage of patients in each group given transfusions in the operating room was 34% in group 1, 28% in group 2, and 7% in group 3 (p less than 0.05). The percentage of all patients receiving transfusions during hospitalization was 68% in group 1, 36% in group 2 (p less than 0.05), and 18% in group 3 (p less than 0.05). Average total units transfused were 2.16 +/- 0.25 in group 1, 0.7 +/- 0.15 in group 2 (p less than 0.05), and 0.37 +/- 0.07 in group 3 (p less than 0.05). The perioperative morbidity rates including myocardial infarctions and strokes were similar. There were no deaths in group 3. Combining complementary conservation measures is effective in reducing homologous blood transfusions, and the need for transfusion can be safely reduced by allowing profound hemodilution during bypass.

Aged↗
PubMed1991

Massive hemoptysis due to broncholithiasis.

Massive hemoptysis due to broncholithiasis is rare. Such a case is presented here, and the literature is reviewed. Surgical resection is the preferred definitive therapy, as a lack of bronchial artery collaterals limits the utility of bronchial artery embolization.

Aged↗