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Biomedical subjects

J M Jenkins

Publications and source records attributed to J M Jenkins.

At least 145 records · Page 8Linked to original sources
PubMed1988

Prevention of stroke during carotid endarterectomy.

From 1976 through 1985, 2857 carotid reconstructive procedures were performed on 2087 patients. Postoperative neurologic deficit occurred in 59 patients (2.1%). Thirty one patients (1.2%) suffered deficits that were permanent while 25 patients (0.9%) cleared to be discharged normal. In the last 5 years of the study, an aggressive approach was taken in cases where the patient was noted to have a postoperative neurologic change. It is routine to allow the patient to awaken in the operating room and to perform a simple neurologic examination prior to transport to the recovery room. If a neurologic change occurs during the postoperative period, immediate exploration is undertaken without preliminary testing. With this policy, 20 patients underwent exploration of the operated carotid artery and six of these patients recovered completely. To reduce the stroke rate from carotid endarterectomy (CE), technical errors must be kept to a minimum. Prevention of hypoperfusion with a shunt and careful mobilization of the artery to prevent microembolization should be practiced. Postoperative thrombosis can be decreased by the routine use of platelet antiaggregates and the avoidance of perioperative hypotension. Reperfusion of injury can be minimized by control of postoperative hypertension and proper preoperative selection of patients. Postoperative neurologic deficit following CE remains a relatively rare event and consequently sufficient experience in the treatment of this problem is difficult to acquire.

Blood Pressure↗
PubMed1988

Ruptured abdominal aortic aneurysm: a 25-year experience and analysis of recent cases.

An 8-year experience with treatment of 58 patients with ruptured abdominal aortic aneurysm (RAAA) is reviewed with hospital mortality of 25.9 per cent. Added to a previously reported experience, 115 patients have been treated over 25 years with 33 per cent mortality. Preoperative hypotension, free rupture, venous injury, and massive transfusion were found to be associated with mortality. Interhospital transfer, preexisting coronary or pulmonary disease, known aneurysm, anemia, delay in surgery, and operative time were not found to predict outcome. Some patients are normotensive at presentation, providing an excellent chance for survival when expeditious diagnosis and treatment are carried out. Optimal operative management, complications, and causes of death are discussed. The role of computed tomography (CT) in diagnosis is considered. Elective resection of known aneurysms is the most important factor in reducing deaths from RAAA. The role of regionalization of care is unclear, since some patients cannot be safely transported. However, some evidence for optimal results in specialized centers is presented.

Aged↗
PubMed1987

Distribution of iodinated proteins in Dipetalonema viteae after surface labelling.

Adult females of the filarial parasite Dipetalonema viteae were radiolabelled using chloroglycoluril and different concentrations of iodine with and without carrier iodide. A detailed quantitative analysis of the distribution of the labelled proteins were carried out using sodium dodecylsulfate and beta-mercaptoethanol to isolate the cuticle after different iodination periods. The highest specific activity was found in the pellet, which comprised the cuticular cortical zone with the highly insoluble epicuticle. However, 50% of the radiolabelled proteins were recovered in the extracts, which contained solubilized material from the somatic compartments and the basal and median zones of the cuticle. The data indicate that the isolation of surface-iodinated antigens of filariae is hampered by the presence of a detergent-insoluble epicuticle. Radiolabelled antigens solubilized by detergents are either proteins from internal somatic or cuticular regions or proteins adsorbed onto the epicuticle.

Animals↗
PubMed1987

The lesser saphenous vein: autogenous tissue for lower extremity revascularization.

From December 1980 to December 1985, 54 patients underwent 56 lower extremity arterial procedures with the use of lesser saphenous vein (LSV) as graft material. LSV was used in all cases because a satisfactory greater saphenous vein (GSV) was unavailable to accomplish the proposed revascularization. Indications for operation were rest pain, ulceration, and gangrene (74%), and 26% had claudication alone. Fifty of the 56 procedures were femorotibial and femoroperoneal bypasses. Three graft combinations were used: LSV alone (29), lesser saphenous vein and other autogenous vein composites (LSV/AUTO) (14), and lesser saphenous vein with synthetic composite grafts (LSV/SYN) (13). Graft patency rates were determined by life-table analysis. The 3-year patency rate for LSV was 60% and for LSV/AUTO was 38%. LSV/SYN graft composites had a graft patency rate at 18 months of 21%. These data suggest that the LSV may function as an autogenous venous graft for lower extremity revascularization when sufficient GSV is not available.

Arteriovenous Shunt, Surgical↗
PubMed1987

Primary graft infections.

An amputation rate of 8% to 52% and a mortality rate of 13% to 58% make vascular prosthetic graft infections the most dreaded complication facing a vascular surgeon. In 1978 a randomized prospective double-blind study reported a statistically significant decrease in wound infections in patients treated with prophylactic antibiotics whereas the graft infection difference only approached statistical significance. The present study reviews 2614 arterial prosthetic grafts implanted from January 1975 through June 1986. Twenty-four patients were identified as having a prosthetic graft infection, yielding an overall infection rate of 0.92%. Staphylococcus aureus was the most common organism, occurring in one third of the cases. The most common graft material was polytetrafluoroethylene (PTFE) (33%) followed by Dacron (29%), composite PTFE and Dacron (20%), and umbilical vein grafts (9%). Diabetes was a common factor in one third of the patients. Symptoms of infection were present in 15 patients (63%) within 3 months of operation, with 11 patients showing symptoms within 30 days. The longest interval between operation and onset of symptoms was 48 months. Prophylactic antibiotics were administered to 22 of the 24 patients, but in only 7 of the 22 (29.5%) were they given according to our usual practice. All patients required removal of the infected prosthesis, with limb loss in 17% and death in 17%.

Anti-Bacterial Agents↗
PubMed1987

Lead configurations in esophageal electrocardiography.

There are many clinical situations that present the need for special purpose electrocardiography using standard equipment. These include monitoring cardiac activity from temporary myocardial leads implanted following cardiac surgery, detecting signals from intracardiac catheter leads, and noninvasive atrial recording from the esophagus. It is often difficult to connect nonstandard leads and access the individual amplifiers. In this article, we present the case for an esophageal electrode such as the Pill Electrode (Arzco Medical Electronics, Inc., Chicago, IL). We describe several configurations for connecting this electrode to electrocardiographs and comment on the merits and shortcomings of each method.

Electrocardiography↗
PubMed1987

Development of a template boundary algorithm to determine the ST-T threshold for silent ischemia.

A template boundary algorithm which quantitatively determines ST-T variability has been implemented and tested using seven normal patients. Relatively uniform variability was demonstrated throughout the ST-T segment in these patients during single lead continuous electrocardiographic monitoring at bedrest. The range of variability appears to be a function of both R wave and T wave amplitude. This algorithm appears to have potential utility in defining the ischemic criteria for silent ischemia.

Algorithms↗
PubMed1987

Recurrent carotid stenosis. Incidence and management.

The actual incidence of recurrent carotid occlusive disease is not known. From January 1974 through December 1984, fifty-four patients underwent at least one second carotid endarterectomy or reconstructive procedure at St. Thomas Hospital in Nashville. Five patients required a third carotid operation. This retrospective study examines case reports, risk factors, patient presentation, interval of recurrence, and pathology involved. Surgical techniques and results are described. Complications occurred in six patients undergoing a total of 66 operations for an overall incidence of 9 per cent. Thrombosis was minimized by the use of antiplatelet drugs. Follow-up of patients ranged from one to 84 months. Four main causes for restenosis are discussed.

Aged↗
PubMed1986

Abnormal steroid excretion in gestational trophoblastic disease complicated by ovarian theca-lutein cysts.

Serum and urine steroids were examined in two subjects with trophoblastic disease accompanied by large ovarian theca-lutein cysts and compared with those from 10 patients with trophoblastic disease but without palpable cysts. In the patients without cysts normal values were obtained for serum oestradiol, progesterone, 17 alpha-hydroxyprogesterone and androstenedione, and for urinary total oestrogens, pregnanediol, pregnanetriol, and 17-oxosteroids. Nineteen urinary steroid metabolites, quantified by capillary gas-liquid chromatography, were either within reference limits or marginally raised. In several cases relatively minor increases in serum testosterone and cortisol and urinary free cortisol were observed. In contrast, the subjects with cysts showed pronounced excesses of androgen metabolites, 17 alpha-hydroxypregnenolone, pregnanediol, and pregnanetriol, and both exhibited a similar pattern of unusual additional metabolites. The profiles superficially resembled those seen in 21-hydroxylase deficiency adrenogenital syndrome, but there were important discrepancies reflecting known differences in ovarian and adrenal steroid metabolism. Chemotherapy led to decline of human chorionic gonadotrophin concentrations, regression of the cysts, and return to normal of the steroid profile. Excess steroids in the patients with cysts may have originated in the ovary rather than in the trophoblastic tissue.

Adult↗
PubMed1985

The role of antiplatelet drugs in carotid reconstructive surgery.

Neurologic events following carotid reconstructive surgery for symptomatic cerebral occlusive disease are generally reported to be one to two per cent. One of the events leading to this incidence is thrombosis of the endarterectomized internal carotid artery (ICA) after surgery. Since antiplatelet drugs have been found to be effective in altering platelet-induced thrombosis, we undertook a clinical trial of administration of aspirin (or aspirin-like) drugs to a group of patients who were to undergo ICA endarterectomy. This group was then compared to a comparable group from the previous year in whom drugs had not been administered. Thrombosis resulting in hemiparesis occurred on six occasions in five patients in the group that did not receive drugs. Thrombosis was not observed in two patients exhibiting hemiparesis in the drugs group. On the basis of these results, we concluded that the incidence of neurological complications following carotid reconstructive surgery can be further reduced by the use of aspirin and aspirin-like drugs.

Adult↗
PubMed1985

Use of the pill electrode for transesophageal atrial pacing.

The pill electrode, which was developed for esophageal electrocardiography, has found application in transesophageal atrial pacing during procedures such as conversion of tachycardia, electrophysiologic measurement, and acceleration of heart rate to produce stress during cardiac imaging studies. This paper presents theoretical studies that examine the relationship of interelectrode distance, current level, and pulse duration to the achievement of successful capture. Theoretical results agree with our clinical findings, i.e., current levels of 25 mA are effective to sustain capture; increased pulse duration reduces current requirements; and close bipolar spacing combines efficacy with safety. Results of animal studies performed to assess the extent of esophageal burn injury reveal that current levels in excess of 75 mA are required to produce lesions in short-term (under 30 minutes) pacing, and greater than 60 mA in long-term (4 hours) pacing. These results are based on experiments using a pulse duration of 2 ms, and the current levels that produce injury will be considerably lower if longer pulse durations are used. Typical current levels and pulse durations for successful capture are presented for 46 subjects in several new clinical applications. Termination of tachycardia, basic electrophysiologic measurements, and controlled acceleration of heart rate can be performed noninvasively with this technique.

Adolescent↗
PubMed1985

Atrial overdrive pacing for conversion of atrial flutter in children.

Twenty-three successive patients with 27 different episodes of sustained atrial flutter were treated with atrial pacing for conversion of the tachyarrhythmia; 15 patients with 16 episodes of atrial flutter underwent intracardiac right atrial pacing and eight patients with 11 episodes of atrial flutter were treated with transesophageal atrial pacing. Ten of sixteen episodes (63%) and eight of 11 episodes (73%) were successfully converted using intracardiac and transesophageal techniques, respectively. Mean flutter cycle length for all 27 episodes was 219 ms (mean heart rate 274 beats per minute); successful pacing conversion cycle length (n = 15) was 72% of the flutter cycle length. Hemodynamic, electrophysiologic, and roentgenographic data were not predictive of conversion by either technique. Induction of localized atrial fibrillation or failure to meet critical pacing criteria may explain pacing failures. Based on this experience, a trial of transesophageal atrial pacing for acute conversion of any episode of atrial flutter in children prior to direct current cardioversion is recommended.

Adolescent↗
PubMed1984

Thresholds for transesophageal atrial pacing.

To determine the thresholds for transesophageal atrial capture, as well as factors that may influence the thresholds, we measured the minimal current and pulse width required to pace the atria through transesophageal bipolar lead systems in 12 patients, ranging in age from 1 day to 19 years, during 19 episodes of reentrant supraventricular tachycardia. Depending on the patients' age and size several electrode catheters were used. The protocol called for 1-msec step-wise increments in pulse width. At each pulse width the current was increased by 1 mamp until capture was achieved. The mean minimal pulse width and mean minimal current required for capture were 5.8 msec and 13.6 mamp, respectively. Atrial capture was achieved in 75% of attempts at a pulse width and current equal to or less than 6.5 msec and 17.5 mamp, respectively. No correlation between current and pulse width on the one hand and age, height, weight, or body surface area on the other was detected. Likewise neither electrode type nor existence of structural heart disease influenced the threshold required for capture. We conclude that atrial capture can be readily achieved through transesophageal electrodes and is not influenced by the subject's age or size.

Adolescent↗
PubMed1984

Spontaneously acquired anti-factor VIII antibodies: report of a patient with adenocarcinoma of the prostate.

Anti-factor VIII antibodies, inherited or acquired inhibitors of the factor VIII molecule, have not been reported previously in the urological literature. Although more common in hemophiliac patients who have received multiple transfusions, this anticoagulant may be the cause of severe hemorrhage in nonhemophiliac patients. We describe a patient with carcinoma of the prostate and an unsuspected anti-factor VIII antibody, who experienced excessive postoperative bleeding and prolonged hospitalization following a vesicolithotomy and bilateral orchiectomy. A prolonged partial thromboplastin time and a significant decrease in measurable factor VIII clotting activity in a patient with no history of bleeding problems are essential clues in making the diagnosis of a factor VIII inhibitor. This coagulation defect is treated best with prothrombin complex concentrates, which contain vitamin K dependent clotting factors.

Adenocarcinoma↗
PubMed1983

Lectin-resistant variants of mouse melanoma cells. II. In vitro characteristics.

Lectin-resistant variants of B-16 melanoma cells were selected with wheat-germ agglutinin, ricin and concanavalin A. They exhibited altered metastasizing capacity and tumorigenicity in C57BL mice. Several in vitro properties were defined and compared including homotypic adhesiveness, microfilament organization, melanin release, activity of tyrosine hydroxylase, DNA content, and karyotypes. The possible relevance of these properties in vitro for the malignant behavior displayed in vivo is discussed. The usefulness of this approach of selecting surface variants to study the problem of metastasis is also discussed.

Animals↗