Coupling of skeletal muscle to a prosthesis for circulatory support

A durable bond between the end of skeletal muscles and prosthetic structures could, with appropriate linkage, allow circulatory support power by synchronous and/or sequential contraction of several in situ conditioned muscles. Potential advantages relative to a myoplasty wrap involve 1) less traumatic dissection, 2) efficient linear force development, 3) selectable contraction rate, 4) greater stroke work, 5) independent control of muscle pre-load and end diastolic pressure, and 6) independent control of duration of muscle tension and ejection time. However, no existing means of tissue-prosthetic bonding appears adequate. Practicality would demand that full tension bearing capacity by the bond take no longer than muscle conditioning. A prosthesis was developed to achieve those goals. As scaled for this study, it is made of 7,200-7,800 unspun, unplaited, 22 to 26 microns diameter polyester fibers swaged into four taper needles for weaving through distal muscle. The other end is formed into a polyurethane sheathed kernmantel cord for distal fixation. Devices were implanted in six 3 to 4 kg rabbits (unilateral posterior tibial tendon replacement, random side selection with contralateral dissection/closure controls), and their tensile strength was tested at 30 days. All healed well; leg movements were normal after 1 week. Limbs were frozen at -70 degrees C between death and testing. Control failure occurred at 243 +/- 94 N and experimental at 163 +/- 44 N (p = 0.065, t-test); highest estimated requirement was 17.2 N. Interface strength was adequate by 30 days. Continued investigations, addressing other questions, are warranted.     

Remote recollection of preoperative pain in patients undergoing excision of endometriosis

To determine the accuracy of postoperative recall of preoperative pain, this prospective, longitudinal study was conducted by a general gynecologist in private practice at a referral center. Before excision of endometriosis at laparoscopy or laparotomy and again at 6 to 18 months after surgery, 168 patients completed a 5-point scale assessing 11 symptoms that may be related to endometriosis. For 6 of the 11 symptoms, over 50% of patients had exact recall of pain level. For 10 symptoms, over 80% recalled their preoperative pain level within +/-1 point. Patients requiring reoperation were most likely to recall preoperative pain levels accurately. Those not requiring reoperation tended to inflate slightly their remote assessment of preoperative pain, indicating that successfully treated patients tend to forget how much they formerly hurt.     

Gray-scale ultrasound: utility preoperatively and postoperatively in a patient with obstructive jaundice

We present a case of obstructing calculi of the common bile duct diagnosed by ultrasonography. Postoperatively, a sterile abscess due to bile leakage at the distal common bile duct developed, and was also diagnosed by ultrasound Ultrasonography was useful in following the course of clearing of the bile collection. Preoperative ultrasound evaluation of the jaundiced patient should be followed by postoperative sonography, especially if complications occur.     

Mucinous biliary obstruction associated with a cystic adenocarcinoma of the pancreas

Obstruction of the biliary tree by large amounts of mucinous material is reported in a patient with a mucin-producing cystic adenocarcinoma of the pancreas invading the common bile duct. Although preoperative endoscopic retrograde cholangiography suggested bile duct invasion, mucinous obstruction, as in the previous cases in which it has been reported, was not suspected. Mucinous obstruction, although unusual, should be considered in patients with cystic carcinomas of the pancreas in the presence of jaundice or episodes of cholangitis.     

Cerebrospinal fluid shunts

Arginine-insulin stimulation and IV glucose suppression (AIGT) tests were used to evaluate release of insulin and growth hormone. Adult patients responded normally. Hypopituitary patients showed no hGH response. One third of short normal patients showed abnormal hGH responses to glucose suppression. Two thirds of the short normal patients showed poor insulin responses to either amino acid or glucose stimulation. Such patients might have abnormalities in release mechanisms for insulin and suppression mechanisms for hGH and this might contribute to their growth failure.     

Calciphylaxis in man. A syndrome of tissue necrosis and vascular calcification in 11 patients with chronic renal failure

Eleven patients with chronic renal failure and presumed secondary hyperparathyroidism developed a syndrome of medial calcinosis of the arteries and painful ischemic ulcers of the fingers, legs, or thighs, or any combination of the three. Five patients required maintenance hemodialysis; six had functioning renal homografts. Severe hyperphosphatemia had existed in each; seven showed roentgenographic evidence of subperiosteal resorption. Similarities are evident between the lesions and experimentally produced calciphylaxix. The lesions demonstrated a relentless, progressive course, with serious morbidity and mortality. Hyperplastic or adenomatours parathyroid tissue was removed from ten of 11 patients unergoing surgical procedures; healing followed in seven patients. Treatment with phosphate-binding antacids to lower serum phosphorus levels may prevent this syndrome. Total or subtotal parathyroidectomy should be considered when ischemic skin lesions appear in uremic patients or in renal transplant recipients.     

Polymer-carbon black composite sensors in an electronic nose for air-quality monitoring

An electronic nose that uses an array of 32 polymer-carbon black composite sensors has been developed, trained, and tested. By selecting a variety of chemical functionalities in the polymers used to make sensors, it is possible to construct an array capable of identifying and quantifying a broad range of target compounds, such as alcohols and aromatics, and distinguishing isomers and enantiomers (mirror-image isomers). A model of the interaction between target molecules and the polymer-carbon black composite sensors is under development to aid in selecting the array members and to enable identification of compounds with responses not stored in the analysis library.     

Peyer''s-patch-associated synthesis of immunoglobulin in germ-free, specific-pathogen-free, and conventional mice

The synthesis of immunoglobulins G, A, and M has been studied in Peyer's patches together with closely associated intestinal mucosa and in small intestine distant from Peyer's patches in specific-pathogen-free (SPF) Swiss mice and conventional and germ-free C3H mice. Thissue fragments were cultured in vitro in medium containing 14C-labelled amino acids, and newly synthesized proteins were detected by radioimmunoelectrophoresis. Small intestine from SPF and conventional animals synthesized almost exclusively IgA. No immunoglobulin synthesis was detectable in germ-free intestine. In contrast, the Peyer's patches and associated mucosa of all the groups of mice synthesized IgG, IgA, and IgM. This observation is discussed in relation to the possible role of the Peyer's patches as a source of precursors for immunoglobulin-producing cells in the intestine.     

Pancreatic cancer screening. Analysis of the problem and the role of radionuclide imaging

The clinical, surgical, and pathologic findings in a five year prospective study of 192 patients referred with a high probability of pancreatic cancer are reported. We have defined the requirements of any pancreatic imaging procedure as its ability to distinguish a normal pancreas from pancreatic cancer or chronic pancreatitis and the capability of detecting tumors less than 5 cm in diameter. There was a 47 percent incidence of pancreatic disease (27 percent pancreatic cancer and 20 percent chronic pancreatitis). Prospective radionuclide imaging as routinely performed was found to be of little clinical value in this patient population; it was neither specific nor sensitive to pancreatic cancer or chronic pancreatitis. Preliminary data with longitudinal multiplane emission tomography show an improved diagnostic accuracy and the ability to detect resectable tumors, but its efficacy needs to be prospectively compared with other screening tests on a carefully defined patient population.