PubMed Health⌕ Search

Biomedical subjects

J M Jenkins

Publications and source records attributed to J M Jenkins.

At least 19 recordsLinked to original sources
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↗
PubMed1992

The detrimental influence of functional ovarian cysts during in-vitro fertilization cycles.

Reviewing 780 in-vitro fertilization (IVF) cycles, where buserelin was commenced in the preceding luteal phase and human menopausal gonadotrophin on day 4 of the ensuing menses, 53 cycles were identified with sonolucent cysts (30-50 mm diameter). Of the latter 53 cycles, the serum oestradiol was significantly greater on day 4 in 22 cycles abandoned for poor follicular development than in 31 cycles which proceeded to oocyte retrieval (P less than 0.05). Of the 31 cycles proceeding to oocyte retrieval, nine had a day 4 serum oestradiol greater than 200 pmol/l (95th centile for day 4 oestradiol in patients without apparent cysts), and these cycles produced significantly fewer grade 1 embryos than the cycles with day 4 oestradiol levels less than or equal to 200 pmol/l (P less than 0.05). Six of the 53 cycles with cysts resulted in conception, and all of these cycles had a day 4 serum oestradiol less than 200 pmol/l. Among the 53 cycles with ovarian cysts, the serum progesterone on the day of abandonment in four cycles and on the day of human chorionic gonadotrophin administration in one non-abandoned cycle, was above the range established for 104 cycles without cysts. No significant difference was seen in day 4 serum androstenedione levels, and the day 4 serum progesterone was less than 5 nmol/l in all but one patient. Functional activity of ovarian cysts is associated with an adverse influence on IVF cycles.

Androstenedione↗
PubMed1992

Juxtarenal aortic occlusion.

The authors' experience with 113 aortic occlusions in 103 patients during a 26-year period (1965 to 1991) is reviewed. The authors found three distinct patterns of presentation: group I (n = 26) presented with acute aortic occlusion, group II (n = 66) presented with chronic aortic occlusion, and group III (n = 21) presented with complete occlusion of an aortic graft. Perioperative mortality rates were 31%, 9%, and 4.7% for each respective group and achieved statistical significance when comparing group I with group II (p = 0.009) and group I with group III (p = 0.015). Group I presented with profound metabolic insults due to acute ischemia and fared poorly. Group II presented with chronic claudication and did well long-term. Group III presented with acute ischemia but did well because of established collateral circulation. The treatment and expected outcome of aortic occlusion depends on the cause.

Actuarial Analysis↗
PubMed1992

In search of a perfect partnership.

There's no question that our partnership is a natural, given the technological emphasis in modern medicine. My comments are not intended as criticism, but offered in the spirit of broadening our mutual understanding. I believe that open communication will enhance our continued collaboration in this interdisciplinary effort and yield significant advances in medical science.

Algorithms↗
PubMed1992

Ventricular tachycardia detection using bipolar electrogram analysis is site specific.

While algorithms for bipolar intraventricular electrogram analysis have potential use in complementing rate criteria for ventricular tachycardia (VT) detection by implantable antitachycardia devices, the sensitivity of such algorithms to the intracavitary site of electrogram detection has not been determined. In this study, unfiltered (1-500 Hz) electrograms were recorded from a bipolar electrode catheter initially positioned at the right ventricular (RV) apex (site 1) of 12 patients during sinus rhythm (SR1) and during induced monomorphic VT (VT1). Sinus rhythm (SR2) and the identical VT (VT2) were recorded a second time after repositioning the same electrode catheter within the RV apex (site 2) 7-44 mm (mean +/- SD = 15 +/- 10) from its original site. The data were digitized at 1,000 Hz. Templates from SR1 and SR2, respectively, were compared subsequently with individual intraventricular electrograms from 15-25 sec passages of SR1 and VT1 and SR2 and VT2, respectively, using correlation waveform analysis. At site 1, the mean patient correlation coefficient ranged from 0.982-0.998 during SR1 and 0.062-0.975 during VT1. At site 2, the mean patient correlation coefficient ranged from 0.995-0.998 during SR2 and 0.113-0.983 during VT2. Using a correlation threshold of 0.9, VT was differentiated from SR in 11/12 patients (91%) overall: 8/12 patients (67%) at site 1, 9/12 patients (75%) at site 2, and 6/12 patients (50%) at both sites. Thus, while discrimination of VT from SR is feasible with morphological analysis of bipolar right ventricular intracavitary electrograms, the accuracy of bipolar intraventricular electrogram analysis may depend upon intracavitary electrode location in selected patients.

Algorithms↗
PubMed1992

The evolving surgical management of recurrent carotid stenosis.

The traditional approach to recurrent carotid stenosis has been repeat endarterectomy or patch angioplasty. Concern with the durability of repeat carotid endarterectomy has resulted in our use of carotid resection with autogenous graft interposition. This study was designed to determine the outcome and efficacy of carotid resection compared with repeat carotid endarterectomy in the management of recurrent carotid stenosis. From 1974 to 1991, 162 operations (repeat carotid endarterectomy 105, carotid resection 57) were performed for recurrent carotid stenosis. Indication for operation was hemispheric symptoms in 63% of patients, nonlateralizing symptoms in 25%, asymptomatic stenosis in 7%, and previous stroke in 5%. Ninety-one percent of patients had stenosis greater than 90% on arteriography. The perioperative stroke rate for carotid resection was 3.5%, with a subsequent rate of 0.0064 strokes per year. For repeat carotid endarterectomy, the perioperative stroke rate was 1.9% with a subsequent rate of 0.011 strokes per year. Graft patency after carotid resection was 93% (mean follow-up, 35 months). Four patients treated with carotid resection had graft thrombosis, and two of the four remained asymptomatic. After repeat carotid endarterectomy, one patient had carotid thrombosis, and recurrent stenosis greater than 50% developed in 23 patients (mean follow-up, 64 months). Twenty patients treated with repeat carotid endarterectomy underwent an additional operation for further symptomatic recurrent carotid stenosis. We conclude carotid resection is a safe and effective alternative to repeat carotid endarterectomy for patients undergoing operation for recurrent carotid stenosis.

Aged↗
PubMed1991

Effects of increased heart rate and sympathetic tone on intraventricular electrogram morphology.

Electrogram pattern recognition by way of morphologic analysis has been proposed as a technique that may improve discrimination of ventricular tachycardia from sinus rhythm by antitachycardia devices. The potential impact that increases in heart rate and sympathetic tone could have on such techniques, however, has not been previously determined. A comparative study was undertaken to quantify possible changes in ventricular electrogram morphology using correlation waveform, area of difference, and amplitude analyses in 6 patients during atrial overdrive pacing at cycle lengths of 600 and 400 ms (group A), in 13 patients during infusions of physiologic doses of epinephrine (group B), and in 20 patients undergoing infusions of isoproterenol (group C). Four patients were in both groups A and B. A bipolar intraventricular template of cardiac depolarization during sinus rhythm at rest was compared with depolarization during subsequent passages of sinus rhythm at rest and subsequently increased heart rate. In 36 of 39 patients, waveform configuration as assessed by correlation waveform analysis remained relatively stable during atrial overdrive pacing, epinephrine infusion, and isoproterenol infusion when compared with sinus rhythm at rest. The correlation value did not fall below 0.950 in any patient. Area of difference values for the same 36 patients changed by an average of 6 and 37% during atrial overdrive pacing at cycle lengths of 600 and 400 ms intervals, respectively, by 3% during epinephrine infusion, and by 17% during isoproterenol infusion. In these same patients, there was an average change in electrogram amplitude of -1% during atrial overdrive pacing at 600 ms, 26% during pacing at 400 ms, -1% during epinephrine infusion, and 12% during isoproterenol infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗