High blood pressure. A side effect of drugs, poisons, and food

A variety of therapeutic agents or chemical substances can induce either a transient or a sustained increase in blood pressure. These agents increase arterial pressure by either causing sodium retention and extracellular volume expansion or directly or indirectly activating the sympathetic nervous system. Some agents act directly on arteriolar smooth muscle. For certain agents, the mechanism of pressure elevation is mixed or unknown. Paradoxically, some agents that are used to lower arterial pressure may acutely increase arterial pressure. Also, a rebound increase in pressure may be encountered after discontinuation of certain antihypertensive agents. In general, these chemically induced increases in arterial pressure are small and transient; however, severe hypertension involving encephalopathy, stroke, and irreversible renal failure has been reported. Careful evaluation of a patient's drug regimen may identify chemically induced hypertension and prevent the need for evaluation and therapy. This study reviews the therapeutic agents or chemical substances that elevate blood pressure and their mechanisms of action.     

Determination of the in situ forces and force distribution within the human anterior cruciate ligament

The in situ forces and their distribution within the human anterior cruciate ligament (ACL) can clarify this ligament's role in the knee and help to resolve controversies regarding surgical treatment of ACL deficiency. We used a universal force-moment sensor (UFS) to determine the magnitude, direction, and point of application of the in situ forces in the ACL in intact human cadaveric knees. Unlike previous studies, this approach does not require surgical intervention, the attachment of mechanical devices to or near the ACL, or a priori assumptions about the direction of in situ force. Anterior tibial loads were applied to intact knees, which were limited to 1 degree of freedom at 30 degrees flexion. The in situ forces developed in the ACL were lower than the applied force for loads under 80 N, but larger for applied loads of more than 80 N. The direction of the force vector corresponded to that of the anteromedial (AM) portion of the ACL insertion on the tibial plateau. The point of force application was located in the posterior section of the anteromedial portion of the tibial insertion site. The anterior and posterior aspects of the anteromedial portion of the ACL supported 25% and 70% of the in situ force, respectively, with the remainder carried by the posterolateral portion. We believe that the data obtained with this new UFS methodology improves our understanding of the role of the ACL in knee function, and that this methodology can be easily extended to study the function of other ligaments.     

UVB-induced suppression of the mixed epidermal cell lymphocyte reaction is critically dependent on irradiance

The mixed epidermal cell lymphocyte reaction (MECLR) is a commonly used method to study the effects of ultraviolet B (UVB) radiation on the skin immune system. In UVB experiments dosimetry is very important. The influence of irradiance on the MECLR was studied in vitro using Philips FS40 lamps with variable UV intensities. Irradiation of isolated epidermal cells with high irradiance impaired the alloactivating capacity more than irradiation with low irradiance. In vivo, the influence of long-term UVB exposure on the MECLR was studied by treating normal healthy volunteers with suberythemagenic doses of UVB thrice weekly during 4 weeks. The first set of experiments, using low irradiance Sylvania UV-21 F75/85 W lamps, resulted in a decrease of MECLR responses of 83.1%. In the second set of experiments performed a year later, employing an identical protocol except for the use of high irradiance Waldmann UV-21 F85/100 W lamps, an increase of MECLR responses of 99.7% was observed. Volunteers of both sets of experiments received equal doses of UVB. In conclusion, this study shows that in vitro UVB-induced suppression of the MECLR is critically dependent on irradiance and therefore might explain contradictory results described in the literature. The in vivo data suggest that, comparable to the in vitro experiments, irradiance may influence the effects of UVB irradiation in vivo. Further experiments should prove whether this is indeed the case.     

Large-scale screening for factor V Leiden mutation in a north-eastern German population

A 37-year-old man was referred with thoracic pain after a deceleration trauma. He also had a cerebral contusion and a wrist fracture. There were no sings of hypovolemic shock. Computerized tomography (CT) of the chest and transoesophageal echocardiography (TEE) demonstrated a type B aortic dissection originating just distal to the left subclavian artery. There was a patent false lumen without rupture or distal ischaemia. Conservative treatment was given. A paralytic ileus developed and abdominal complaints persisted for several months. Angiography showed normal patency of mesenteric vessels. On follow-up, 3 years after the accident a slight aortic dilation was found on CT thorax without development of a post-dissection aneurysm. Blunt thoracic injury to the aorta usually gives rise to aortic rupture in the region of the isthmus, which can be complete or partial. In the latter case a false aneurysm may develop. An intimal tear after blunt trauma leading to type B aortic dissection rarely occurs. General principles regarding treatment of type B dissection also apply to this particular condition.     

Tendons attached to prostheses by tendon-bone block fixation: an experimental study in dogs

To develop a method of tendon attachment to a metallic endoprosthesis, we evaluated fixation strength, clinical function of the tendon, and morphological changes in an experimental model. The canine supraspinatus tendon was removed from the greater tubercle of the humerus and attached to a titanium prosthesis. In 12 animals, the bone block underlying the tendon insertion was preserved and attached in one limb; the soft part of the tendon was attached directly to the prosthesis in the contralateral limb. Fixation strength was evaluated after 16 weeks of in vivo implantation (12 specimens) and compared with the in vitro fixation strength (12 specimens) and with intact normal controls (six specimens from cadavera). Function of the tendon in vivo was evaluated by force-plate analysis (at 3-week intervals). All specimens were evaluated histologically. Sixteen weeks after surgery, the tendon-bone block attachment was significantly stronger (mean, 16%) than the direct tendon attachment and not significantly different from the normal control, and the direct tendon attachment was significantly weaker (mean, 68%) than the normal control. There was significantly more weight-bearing on the limbs with a tendon-bone block attachment than on the limbs with a direct tendon attachment at both 3 and 6 weeks postoperatively. Both front legs showed increased weight-bearing with time, but the differences were not statistically significant. Anchorage by tissue ingrowth to the titanium prosthesis was found consistently--there was bone ingrowth in the tendon-bone block attachments and fibrous tissue ingrowth in the direct tendon attachments. When a bone block was preserved, the strength and stiffness were comparable with those of a normal tendon insertion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Why quality of life measures should be used in the treatment of patients with respiratory illness

Treatment of airways disease is directed towards improving patients' health and well-being. Measurements of airways function do not reflect all the disease activity present in the airways that may affect the patient. Spirometry correlates poorly with health. Physicians appear to estimate their patients' health using criteria different from the patients themselves. Quality of life questionnaires provide a method of quantifying the effect of disease on patients' lives. They can summarize a number of aspects of the disease and provide an overall estimate of the effect of disease and benefits due to therapy. They have the potential to identify a threshold response to treatment that may be considered "worthwhile", and allow comparison between therapies with respect to the health gain that each provides.     

Fear of humans in Japanese quail selected for low or high adrenocortical response

Behavioral reactions to a nearby human were recorded in male Japanese quail of two lines selected for reduced (LS; low stress) or exaggerated (HS; high stress) plasma corticosterone (B) response to brief mechanical immobilization. Their adrenocortical responses to one of three treatments were then examined. These were: no human disturbance (undisturbed controls, CON), capture and return to the home cage before recapture and bleeding after 5 min (CR), or capture and manual restraint for 5 min before blood sampling (CREST). Quail of the HS line showed more fear-related behavior (crouching, escape) and avoidance of the experimenter than did their LS counterparts. Plasma B concentrations were markedly elevated following each capture treatment (CREST > CR) and the response appeared to be more pronounced in quail of the HS than the LS line. These findings indicate that HS quail perceived human contact to be more aversive than did those of the LS line. Avoidance scores and the adrenocortical responses to capture were positively correlated within individual birds. Therefore, simple behavioral tests of fear may have predictive value concerning physiological responsiveness to stressful stimulation.     

Novel technique and instrumentation for laparoscopic application of hemostatic clips

A novel device for applying hemostatic clips in laparoscopic surgery incorporates a distal hook into a multiple-firing titanium clip applier. The hook may be used for blunt dissection of tissue, and to displace and control ducts and vessels during clip application. A single instrument may be used to achieve hemostasis in areas that are difficult to reach, and past pointing problems encountered with straight on clip appliers are alleviated. Comparative testing of the holding force of the curved clips used with this device versus the straight clips used in conventional multiple-clip appliers demonstrated a higher mean pull-off force of 0.473 lbs versus 0.33 lbs. Clinical application of the device in laparoscopic procedures including cholecystectomy, vaginal hysterectomy, Nissen fundoplication, vagotomy, varicocelectomy, and lymphadenectomy show the utility of the hook clip applier.     

Antiproteinuric effect predicts renal protection by angiotensin-converting enzyme inhibition in rats with established adriamycin nephrosis

1. The mechanism of renal protection by angiotensin-converting enzyme inhibition is still the subject of debate. Inhibition of proteinuria might play a role. If so, a good antiproteinuric response to angiotensin-converting enzyme inhibition should predict subsequent protection against renal structural damage. This hypothesis has not been tested in models where treatment is started after the renal disease is well established, i.e. models that mimic the clinical situation. 2. We therefore investigated this hypothesis in 96 male Wistar rats with established adriamycin nephrosis. Reduction of proteinuria was achieved by lisinopril (0, 2, 5 and 10 mg day-1 kg-1) on two different sodium diets (0.3% and 0.05% NaCl). Therapy started 6 weeks after adriamycin (at stable proteinuria) and was continued for 6 weeks. 3. Lisinopril reduced blood pressure by 32 +/- 4% and proteinuria by an average of 72 +/- 7%, with stabilization after 2 weeks. Considerable interindividual differences in antiproteinuric response was found. Glomerulosclerosis score was reduced by 15 +/- 5%. All the effects of angiotensin-converting enzyme inhibitors were enhanced by sodium depletion, but sodium depletion in itself did not affect blood pressure (124 +/- 4 mmHg), proteinuria (664 +/- 68 mg/day) or glomerulosclerosis score (30 +/- 5%). Interestingly, the more proteinuria was reduced initially in an individual rat, the less sclerosis was found in the long term in that rat. 4. In conclusion, angiotensin-converting enzyme inhibition lowers proteinuria and prevents glomerulosclerosis in established adriamycin nephrosis. These effects are enhanced by sodium depletion. The individual short-term antiproteinuric effect predicts the protection against ultimate glomerular damage. This is consistent with the hypothesis that reduction of proteinuria is a mechanism by which angiotensin-converting enzyme inhibitors exert renoprotection.