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Biomedical subjects

J M Jenkins

Publications and source records attributed to J M Jenkins.

At least 91 records · Page 5Linked to original sources
PubMed1993

Cefamandole versus cefazolin in vascular surgical wound infection prophylaxis: cost-effectiveness and risk factors.

PURPOSE: Recent studies of perioperative antimicrobial prophylaxis have indicated an improved efficacy of beta-lactamase-stable cephalosporins compared with cefazolin, the most commonly used prophylactic agent. Previous studies in our institution have revealed a superiority of cefamandole to cefazolin in patients undergoing heart surgery, although there was no difference between cefazolin and cefuroxime in patients undergoing peripheral vascular surgery. This study was therefore designed to compare cefamandole with cefazolin in wound infection prophylaxis in clean vascular surgery. METHODS: The study was conducted from August 1990 through May 1992 and consisted of 893 patients with aortic or infrainguinal arterial procedures randomized to receive either cefamandole or cefazolin. RESULTS: The difference in infection rates associated with cefamandole versus cefazolin prophylaxis (3.2% vs 1.9%, respectively) was not significant (p = 0.42). A cost savings of approximately $95,000 per year at our institution favors the continued use of cefazolin over cefamandole. Risk factor analysis was carried out for preoperative and postoperative events that might have predisposed to infection. Only preoperative use of aspirin and the postoperative finding of a lymphocele correlated with a higher infection rate. CONCLUSIONS: Cefazolin continues to be the most cost-effective antibiotic for prophylaxis in clean vascular surgical procedures.

Adult↗
PubMed1993

The development of functional ovarian cysts during pituitary down-regulation.

This study investigated the development of functional ovarian cysts during pituitary down-regulation prior to in-vitro fertilization (IVF), and identified 16 cases of cysts in 288 IVF cycles studied. Comparing the patients with functional ovarian cysts to the other 272 IVF cycles, there was no significant difference in age or incidence of endometriosis but significantly (P < 0.01) more patients with cysts had ovulatory dysfunction. The serum progesterone was < 5.7 nmol/l in all 16 patients with cysts on day 4 of the IVF cycle, and in eight of these patients the serum progesterone was < 5.7 nmol/l on the day buserelin was commenced. In 10 of the 16 patients with cysts, serum oestradiol concentrations remained elevated despite the prolonged use of buserelin, and the cysts were aspirated. The aspirate in all cases was clear without any suggestion of endometriosis. The cyst aspirates had significantly lower progesterone (P < 0.001), higher androstenedione (P < 0.01) and similar oestradiol concentrations to 10 follicular fluid samples collected at the time of oocyte retrieval. This study suggests that functional ovarian cysts may develop during pituitary down-regulation, and these cysts are follicular cysts rather than persistent corpora lutea or endometriomata.

Adult↗
PubMed1993

A stochastic network model of the interaction between cardiac rhythm and artificial pacemaker.

The electrical interaction between the heart and an artificial pacemaker is often complex. Because of the sophistication and diversity of dual-chamber device algorithms, even experienced cardiologists can have difficulty interpreting paced electrocardiograms (ECG's). In order to study heart-pacemaker interaction (HPI), a computer model of the cardiac conduction system has been developed which includes the effects of artificial pacemaker function and failure. The stochastic network model of cardiac conduction consists of five vertices, each representing a functional electrophysiologic element. Electrophysiologic multidimensional conditional probability functions determine the depolarization status of each vertex. The atrioventricular (AV) node is emulated using a mathematical model which includes the influence of past cycle lengths on AV nodal conduction time. Twenty-three classes of arrhythmias may be simulated and, for pacing simulation, one of 12 antibradycardia pacing modes may be chosen. Random effects of pacemaker malfunction including oversensing, undersensing, or failure-to-capture may be simulated through the use of probability distribution functions. This model should prove useful in the development of pacemaker algorithms, determining patient-specific pacemaker therapy, and predicting causes for apparent pacemaker malfunction. The model has been used in the development of an expert system to analyze paced ECG's for pacemaker function and malfunction.

Algorithms↗
PubMed1993

Real-time arrhythmia identification from automated analysis of intraatrial and intraventricular electrograms.

Implantable cardioverter defibrillators have dramatically improved survival rates for patients at risk of sudden cardiac death, but the occurrence of inappropriate shocks remains an unresolved problem. Various means for better tachycardia detection, chiefly morphological analysis, have been proposed to address this problem. A new computerized scheme entitled Two-Channel Rate-Morphology (2CRM) was introduced. It is a real-time arrhythmia detection algorithm that combines timing and morphology information from intraatrial and intraventricular electrograms for arrhythmia diagnosis. The program 2CRM applies an initial cycle-by-cycle coding scheme followed by contextual diagnosis of underlying rhythm. The program was tested on 36 distinct passages of two-channel intracardiac signals from 30 patients. The distribution of the arrhythmias are as follows: 4 atrial fibrillation, 6 atrial flutter, 6 supraventricular tachycardia, 10 ventricular tachycardia, and 10 ventricular flutter-fibrillation. Of the analyzed 3,417 individual cardiac cycles 3,135 (91.7%) were correctly identified. Contextual diagnosis reversed 123 single-cycle errors to obtain a performance of 3,258 correct out of 3,417 (95.3%). Utilizing an uninterrupted continuous correct contextual diagnosis as indicator of successful arrhythmia detection, 2CRM obtained an accuracy of 34 out of 36 passages (94.4%).

Algorithms↗
PubMed1992

A review of the literature on the use of ultrasonography in schistosomiasis with special reference to its use in field studies. 1. Schistosoma haematobium.

This review presents an outline of the pathology resulting from Schistosoma haematobium infections, and the ways in which the lesions can be investigated. The use of ultrasonography is covered in detail. Ultrasonography can provide direct information about lesions in internal organs, and thus provide information about patterns of morbidity and about the regression of pathological changes after treatment. The method has the advantages that it is non-invasive, and is also relatively inexpensive and can be used under field conditions. Ultrasonography has already been used in a number of epidemiological studies in areas where S. haematobium is endemic. The method has proved to be feasible and useful. However, the methodology used for ultrasound studies has varied considerably, so that it is difficult to make valid comparisons between results obtained in different places or at different times. A standardized methodology for making observations and recording the results is needed if the full potential benefit of using ultrasound in the monitoring of schistosomiasis control projects is to be realised. The correlation of results obtained using ultrasound with the results of clinical, parasitological and other observations has been investigated in a number of studies, but many questions remain to be answered.

Confounding Factors, Epidemiologic↗
PubMed1992

A review of the literature on the use of ultrasonography in schistosomiasis with special reference to its use in field studies. 2. Schistosoma mansoni.

This review presents an outline of the pathology resulting from Schistosoma mansoni infections, and the ways in which it can be investigated. The use of ultrasonography is covered in detail. Ultrasonography can provide direct information about lesions in internal organs, and thus provide information about patterns of morbidity and about the regression of pathological changes after treatment. The method is non-invasive, and can be used under field conditions. Ultrasonography is valuable for the study of hepatosplenic pathology, to detect lesions such as the development of periportal fibrosis and the enlargement of the portal vein, which can indicate the development of portal hypertension. This may lead to a severe outcome, including bleeding from oesophageal varices, which is a principal cause of death from S. mansoni infection. A problem with the use of ultrasonography is that the mild lesions likely to be observed in population surveys are not always easy to assess. Ultrasonography has already been used in a number of epidemiological studies of S. mansoni infection, and has proved to be feasible and useful. However, the methodology used for ultrasound studies has varied considerably, so that it is difficult to make valid comparisons between results obtained in different places or at different times. A standardized methodology for making observations and recording the results is needed if the full potential benefit of using ultrasound in the monitoring of schistosomiasis control projects is to be realised.

Diagnosis, Differential↗
PubMed1992

A review of the literature on the use of ultrasonography in schistosomiasis with special reference to its use in field studies. 3. Schistosoma japonicum.

This paper gives a brief description of the pathology resulting from Schistosoma japonicum infection, and ways in which it can be investigated. It then reviews reports of the application of ultrasound in investigating lesions in schistosomiasis japonica, including papers published in Chinese and Japanese. Ultrasonography has been widely used for the diagnosis of schistosomiasis and for the investigation of pathological changes resulting from the infection. Marked and characteristic changes are observed in the structure of the liver parenchyma in advanced disease. Chronic pathology may be seen as a result of past infection. Animal studies have been used to compare ultrasound images with actual pathological changes. Ultrasonography can also be used to detect early changes, for example periportal fibrosis, which can indicate the development of portal hypertension. The problem of differential diagnosis is discussed.

Confounding Factors, Epidemiologic↗
PubMed1992

Ultrasound in schistosomiasis--a critical look at methodological issues and potential applications.

This is the concluding paper of a series on the use of diagnostic ultrasound in the investigation of schistosomiasis. An earlier chapter in the volume discussed standardization of the methodology, and of recording, when ultrasound is used for epidemiological purposes. The present paper discusses some other requirements for obtaining ultrasound data which can be used to make valid comparisons within and between studies. Since there is an inherent variability in the interpretation of results from ultrasound images, quality control and the training of observers are both essential. It is also necessary to collect more information for each endemic setting about possible concomitant diseases which might lead to misinterpretation of results. Furthermore, the analysis of the data obtained must be uniform if valid comparisons are to be made. A final section considers applications of ultrasonography in research and control programmes. The technique should make it possible to obtain a better understanding of the extent and distribution of organ damage due to schistosomal infection in different geographical areas, and of the way in which lesions develop over time, or may regress in response to treatment. Since ultrasonography will always remain a relatively labour-intensive and expensive technique, it is necessary to establish, in different settings, how its findings correlate with the results of parasitological, serological and biochemical tests. The ultimate aim is to build up a body of information on the potential of ultrasonography, in combination with other procedures, in the various possible approaches to morbidity control.

Clinical Protocols↗
PubMed1992

Cystadenoma of the pancreas in a newborn.

Cystadenoma of the pancreas is a rare entity. In the pediatric population, three cases have been reported. We present a case of cystadenoma of the pancreas in a newborn. The tumor involved the head and body of the pancreas. Subtotal pancreatectomy with preservation of the duodenum, common bile duct, and pancreatic tail was performed.

Cystadenoma↗
PubMed1992

Computerized interpretation of the paced ECG.

Analysis of the paced electrocardiogram (ECG) is important to the follow-up evaluation of patients with implanted pacemakers. Because of the complexity and variability of pacemaker algorithms, diagnosis of paced ECGs is often considerably more difficult than the interpretation of usual ECGs. Automated interpretation of the paced ECG can provide great clinical benefit because few clinicians are adequately trained in the diagnosis of such ECGs for the interpretation of pacemaker functionality. However, comparatively little work has been done in this area, mainly because the diversity and complexity of pacemaker logic makes interpretation, automated or manual, a difficult task. The following paper reviews research in computer interpretation of the pacemaker ECG and presents a new automated method which yields more detailed and accurate results than any previous technique.

Algorithms↗