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Biomedical subjects

L L Jensen

Publications and source records attributed to L L Jensen.

25 records · Page 2Linked to original sources
PubMed1988

Balloon sphincterography. Clinical findings after 200 patients.

There are two muscular mechanisms of fecal continence. The anal sphincter squeezes the anal canal, thus lengthening it and increasing its resistance. The puborectalis kinks the distal rectum, preventing the transmission of intra-abdominal pressures into the anal canal. Balloon sphincterography simultaneously records the shape of the anal canal and distal rectum and measures the strength of the puborectalis and anal sphincter muscles. This allows the physician to evaluate the function of these important muscles in patients with symptomatic defecation disorders such as constipation, incontinence, and rectal prolapse. A cylindrical balloon is connected by a hose to a fluid reservoir filled with liquid barium. The deflated balloon is placed into the anal canal and inflated by raising the fluid reservoir in increments. Fluoroscopy visualizes the balloon's shape and video records the results. Quantitative sphincterogram measurements in patients with defecation disorders include (the three measurements in each category refer respectively to incontinent patients [N = 87], prolapse patients without incontinence [N = 26], and constipated patients [N = 65]); anorectal angle (degrees + S.D.): 114 + 28, 103 + 18, 95 + 19; anal canal length (mm + S.D.): 33 + 11, 38 + 10, 39 + 10; squeeze pressure (cm H2O + S.D.): 68 + 23, 80 + 16, 91 + 22, and opening pressure (cm H2O + S.D.): 52 + 25, 67 + 22, 81 + 24. The method is useful in identifying specific defects, such as paradoxic puborectalis contractions, that can cause constipation, and injuries to the sphincters that can cause incontinence. In over 280 patients with a wide variety of defecation disorders, sphincterography has yielded information not available by standard manometric techniques. It augments the findings of defecography.

Anal Canal↗
PubMed1988

Heightened blood pressure responsiveness to intracarotid infusion of angiotensins in the spontaneously hypertensive rat.

The purpose of this study was to test the hypothesis that intracarotid infusion of angiotensin via a brachial arterial catheter results in a heightened pressor response in the alert spontaneously hypertensive rat (SHR) as previously observed for intracerebroventricular (ICV) injection of angiotensin. We infused angiotensin II and III since these ligands are equivalently potent with respect to peak pressor effect when delivered ICV. We measured somewhat greater pressor responsiveness to AII than to AIII in the Wistar-Kyoto (WKY) normotensive control strain from a baselevel of 133.1 +/- 5.8 (mean +/- SEM) to 151.3 +/- 6.2 mmHg (+13.7%) at the 100 pmol/kg/min dose of AII, and from 132.5 +/- 5.8 to 146.0 +/- 6.1 mmHg (+10.2%) for AIII. The SHR revealed a heightened pressor sensitivity to AII, from a baselevel of 170.0 +/- 3.8 to 200.6 +/- 5.9 mmHg (+18%) while the response to AIII was less dramatic, from 171.3 +/- 2.1 to 189.8 +/- 2.4 mmHg (+10.8%). These findings suggest that a similar heightened pressor responsiveness occurs to peripheral infusion of angiotensin II in the SHR as previously observed to ICV injection.

Angiotensin II↗
PubMed1987

Neurogenic heterotopic ossification.

Neurogenic heterotopic ossification is a potential sequela of neurological disorders, especially spinal cord injury and head injury. The etiology is unknown. Clinical, radiologic, and bone scan findings are typical. Complications may threaten function. The differential diagnosis is crucial in its early stages. Treatment options include diphosphonates, non-steroidal anti-inflammatory drugs, and surgery. This article has reviewed the literature on neurogenic heterotopic ossification (HO), soft tissue ossification of neurologic disease, including pathogenesis, histology, presentation, diagnosis, natural history, complications, and current treatments.

Animals↗
PubMed1986

Balloon topography. A simple method of evaluating anal function.

Balloon topography was developed to simultaneously measure anal canal pressure, anal canal length, and anorectal angle. It is performed using a cylindrical flexible balloon placed into the anal canal and rectum and filled with liquid radiopaque contrast dye under low pressure. The pressure of the dye inside the balloon is controlled by the investigator, and does not vary with changes in balloon volume. The shape of the balloon within the anal canal is recorded using fluoroscopy and plain radiopaques. The patient receives less radiation than he would receive during a single contrast barium enema. We have performed the test on 27 subjects including a normal control, rectal prolapse patients, and incontinent patients. Early results demonstrate the usefulness of the test in examining anal sphincter and pelvic floor function in maintaining fecal continence in health and disease. The test measures multiple aspects of anopelvic function simultaneously that previously required separate investigations.

Aged↗
PubMedDate not supplied

Brain angiotensin: critical role in the ongoing regulation of body fluid homeostasis and cardiovascular function.

The existence of an endogenous brain-angiotensin system and its association with cardiovascular and body water regulation has been recognized for over a decade. Nevertheless, the importance of the brain-angiotensin system to the instantaneous regulation of these processes has not been firmly established. A 5-minute intracerebroventricular (ICV) infusion of the angiotensin antagonist, [Sar1,Thr8]-AII, effectively lowered the blood pressure in normotensive rats. Additionally, application of the selective aminopeptidase inhibitor, bestatin, given alone, resulted in a dramatic increase in blood pressure and a robust drinking response. Both effects were 100% blockable by [Sar1,Thr8]-AII pretreatment. Predictably, an aminopeptidase inhibitor, bestatin, greatly elongated the half-lives of AII and AIII in the cerebroventricles. Since neither of these treatments included the introduction of exogenous angiotensins, we have concluded that perturbations of the endogenous brain-angiotensin system are effective at rapidly influencing both cardiovascular and body fluid homeostasis, thus highlighting the paramount role played by brain angiotensin in their ongoing regulation.

Aminopeptidases↗