Blood flow to the latissimus dorsi muscle pouch during chronic counterpulsation stimulation.

The cyclic contraction of a skeletal muscle ventricle (SMV) stimulated in counterpulsation results in phasic perfusion of the muscle. Perfusion will occur primarily during cardiac systole when the muscle is relaxed. However, the resting preload of the SMV will be systolic arterial pressure, which will impede blood flow to the relaxed muscle. To determine the effect of chronic counterpulsation stimulation on the blood flow to an SMV and identify stimulation regimens that prevent the risk of chronic ischemia, SMVs were created in four mongrel dogs by implementing an implantable mock circulation device. The SMV was stimulated in counterpulsation for 4 weeks after a 2-week vascular delay period and 2 weeks of low-frequency muscle conditioning. During biweekly studies, the muscle was stimulated in four modes against preloads varying from 20 to 120 mm Hg. Resting blood flow decreased significantly at preloads greater than 60 mm Hg. Normalized blood flow increased between 10% and 30% during stimulation; greater increases corresponded to more demanding stimulation modes. The elevated blood flow during stimulation, however, decreased with increasing preload. Stroke work increased with increasing preload until preload exceeded 100 mm Hg. The decreased blood flow and increased stroke work occurring at higher preloads indicate that the supply/demand ratio becomes compromised with increasing preload. A hyperemic response occurred during the resting beats after a stimulated beat, increasing the volume blood flow by as much as 80%. This response occurred regardless of preload or stimulation rate. If the SMV relaxed before the onset of systole, a hyperemic response occurred within the stimulated beat.(ABSTRACT TRUNCATED AT 250 WORDS)

HTLV-III/LAV infection in hemodialysis patients.

Twenty-five (4.8%) of 520 hemodialysis patients were seropositive for antibody to human T-cell lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV) by enzyme immunoassay. Four had high reactivity on enzyme immunoassay and positive results of Western blot tests, and one of the four had a positive culture. The remaining 21 seropositive patients had low reactivity on enzyme immunoassay, negative results of Western blot tests, and negative cultures. All had received blood transfusions and 19 had antibodies to antigens associated with the H9 cell line used to propagate HTLV-III for serological tests. We found that HTLV-III/LAV was not transmitted in the dialysis centers. Frequent blood transfusion places dialysis patients at risk for HTLV-III/LAV infection, but may more commonly lead to false-positive results of enzyme immunoassay tests.

[Image quality assurance in x-ray diagnostic units. Information on DIN 6868 standard series]. / Sicherung der Bildqualität in röntgendiagnostischen Betrieben. Informationen zur Normenreihe DIN 6868.

The Working Group for Standardisation justifies and comments on the establishment of a standard series for image quality assurance in X-ray diagnostic services (DIN 6868). In order to promote compliance with these standards, the users are given some background information on the structure of the standard series and on the recommended procedures to be followed. The definitions for the various hierarchically arranged tests, such as constancy test, status test, acceptance test as well as a definition for the term "base-line image quality" are explained.

Total parathyroidectomy and autotransplantation in secondary hyperparathyroidism.

Sixteen patients with chronic renal failure and symptomatic secondary hyperparathyroidism underwent total parathyroidectomy. Sixteen to 25 fragments of parathyroid tissue measuring 1 cu mm were autotransplanted into the brachioradial muscle. Evidence of "take" of the autotransplant was present in all patients, although four patients still have hypocalcemia and require calcium and vitamin D supplementation. Three patients have experienced late diminution of autotransplant function. Symptomatic improvement occurred promptly in 15 of the 16 patients. Two patients with persistently elevated parathormone levels were treated by partial excision of the implant, and one patient whose autograft functioned inadequately was successfully treated by implantation of cryopreserved autologous parathyroid tissue. Total parathyroidectomy with autotransplantation of parathyroid fragments to the forearm is the preferred surgical procedure for secondary hyperparathyroidism.

Metolazone and spironolactone in cirrhosis and the nephrotic syndrome.

Eighteen patients with hepatic cirrhosis or nephrotic syndrome and having edema and/or ascites were treated during successive periods with metolazone 5 to 40 mg/day, spironolactone 100 mg/day, and with both diuretics concurrently. Metolazone alone produced a marked diuresis, natriuresis, and weight loss in 8 patients. Spironolactone alone had little effect, but the addition of metolazone renewed diuresis and natriuresis and resulted in additional substantial weight losses in all patients responsive to metolazone alone. Concurrent spironolactone and metolazone also induced moderate diuretic effects in some patients who failed to respond to either drug alone. The drugs were well tolerated; the administration of spironolactone with metolazone prevented decreases in serum potassium, which had occurred during treatment with metolazone alone.