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Biomedical subjects

R G Lee

Publications and source records attributed to R G Lee.

At least 127 records · Page 7Linked to original sources
PubMed1987

Patterns of reinnervation and motor unit recruitment in human hand muscles after complete ulnar and median nerve section and resuture.

Following complete ulnar or above-elbow median nerve sections, there was no significant correlation between motor unit size (twitch amplitude) and recruitment threshold, as assessed by spike triggered averaging. This absence of orderly recruitment was attributed to misdirection of motor axons during regeneration. Following median nerve section at wrist level, where the reinnervated muscles have more synergistic actions, orderly recruitment by size appeared to be re-established. Thus, the size principle of motor unit recruitment can be re-established after nerve section in humans, if motor axons innervate their original muscles or ones with closely synergistic functions.

Action Potentials↗
PubMed1987

Liver preservation for transplant. Evaluation of hepatic energy metabolism by 31P NMR.

31P NMR spectroscopy proved to be an excellent, dynamic, nondestructive method for assessing the liver during cold flush and pulsatile perfusion experiments. 31P NMR spectroscopy was used to measure ATP decay, inorganic phosphate appearance, and phosphate chemical shift in the excised mouse livers subjected to cold and warm ischemia. Cold flush followed by cold preservation in saline, Krebs-Henseleit buffer, or Collins' solution showed that Collins' solution resulted in the slowest ATP decay. In temperature-controlled experiments (5 degrees -37 degrees C), ATP decay was much slower with lower temperature. In separate pulsatile perfusion experiments with oxygenated Krebs-Henseleit buffer, hepatic ATP was unchanged for at least 6 hr at 20 degrees C. At 37 degrees C, the NMR spectrum showed changes in the diphosphoesters region, but the ATP remained stable during the 6-hr perfusion. These studies suggest that for long periods of liver preservation, an adequate perfusion method should be developed.

Adenine↗
PubMed1987

Villous regeneration in ulcerative colitis.

Three cases with extensive villous regeneration were identified in a review of 92 colectomy specimens of ulcerative colitis. Villous regeneration was evident grossly as numerous poorly defined zones of velvety mucosa present primarily in the ascending and transverse colon. These zones were characterized histologically by discrete, well-formed villi lined by epithelium with prominent regenerative changes. Occasionally, the epithelium demonstrated an oncocytic appearance that may be the result of adaptive mitochondrial hyperplasia. Distinguishing villous regeneration from epithelial dysplasia may be difficult because several features, including cytologic atypia, dystrophic goblet cells, and a villous configuration, can be seen in both. However, close attention to the nuclear changes and the type of mucous differentiation will aid in the distinction.

Adult↗
PubMed1986

Renal evaluation after CUSA plus Nd:YAG laser for partial nephrectomy.

A technique for partial nephrectomy using a combination of an Ultrasonic Surgical Aspirator and a neodymium:YAG laser provided better hemostasis and decreased total operative time compared to standard methods. Delayed hemorrhage was not seen, and thermal damage to the remaining renal parenchyma was minimal.

Animals↗
PubMed1986

Magnification radiography in osteomyelitis.

Osteomyelitis often eludes early diagnosis because plain film radiography is too insensitive and radionuclide bone scanning is nonspecific. In this study, 90 diabetic patients were studied with plain film and magnification radiographs of their feet. Among the 24 patients with osteomyelitis, plain radiographs suggested the diagnosis in 14 patients and magnification radiography was diagnostic in 18 of these patients. Thus, magnification radiography offers some diagnostic advantage in patients suspected of having osteomyelitis.

Adult↗
PubMed1986

Modification of motor output to compensate for unanticipated load conditions during rapid voluntary movements.

Mechanisms responsible for load compensation during fast voluntary movements were investigated in 20 normal subjects trained to carry out rapid wrist flexions against a standard load. When an unanticipated increase in load occurred, there was a compensatory increase in agonist EMG and decrease in antagonist EMG. Unanticipated decreases in load produced reciprocal changes with a decrease in agonist EMG and an increase in antagonist EMG. The latency of these EMG changes was quite short and compatible with a spinal reflex mechanism rather than a long loop response. The results suggest that mechanisms exist at the spinal level to allow rapid modification of motor programs when unanticipated load conditions are encountered on initiation of movement.

Adult↗
PubMed1986

Adenomas arising in Barrett's esophagus.

Three cases of the unusual esophageal adenoma are described. The patients included two men and one woman, with a mean age of 61 years, who presented with dysphagia or heartburn. Histologically, the esophageal adenomas were composed of dysplastic epithelium in a polypoid configuration, similar to adenomas elsewhere in the gastrointestinal tract. All three adenomas arose within Barrett's esophagus (columnar epithelium-lined distal esophagus), and dysplastic Barrett's mucosa was found in the adjacent mucosa of each case. Critical review of the literature identified three additional cases; similar clinicopathologic features were described. Esophageal adenomas are a complication of Barrett's esophagus and are best considered as macroscopic variants of epithelial dysplasia rather than as isolated adenomatous polyps. As such, they likely represent premalignant lesions.

Adenoma↗
PubMed1986

The histopathology of fundic gland polyps of the stomach.

To assess the histopathologic features of fundic gland polyps (FGP) of the stomach, 83 specimens from 25 patients were examined. In nine patients, FGP were associated with an inherited adenomatous polyposis syndrome; the other 16 patients had nonsyndromic FGP. FGP were microscopically characterized by the presence of fundic glands with variably disordered architecture, a feature not previously emphasized. Disordered architecture, found in 80 of 83 specimens (96%), comprised a spectrum of abnormalities, ranging from prominent glandular and cellular budding, found in 51 biopsies (61%), to irregular tortuous glands, noted in 61 biopsies (75%), to microcysts lined by fundic epithelium, seen in 72 biopsies (87%). The continuous range of these changes suggested that FGP arise through progressive formation and unfolding of secondary glandular buds, to result in cystic dilatation. No differences were found between syndromic and nonsyndromic FGP with respect to histologic features or mucin histochemistry, including presence of O-acylated sialomucins.

Adenomatous Polyposis Coli↗
PubMed1986

The colitis of Behçet's syndrome.

A 29-year-old woman with Behçet's syndrome developed a severe colitis that ultimately required colectomy. The colectomy specimen showed extensive mucosal ulceration with varying longitudinal, fissuring, and aphthoid configurations, usually occurring within a background of normal or focally inflamed mucosa, and associated with a lymphocytic vasculitis involving submucosal veins. A review of the literature reveals 29 additional cases of colitis complicating Behçet's syndrome. The colitis is characterized by multiple ulcers of diverse size, appearance, and depth of penetration involving any portion of the large bowel, occasionally with coexistent ileal or anal disease. Vasculitis may be the underlying process. Although it resembles other types of colitis, particularly Crohn's colitis, differences in clinical and pathologic features suggest that the colitis of Behçet's syndrome represents a distinct condition.

Adult↗
PubMed1986

Demonstration of hematobilia using technetium-99m labeled red blood cells.

A 75-year-old woman, who presented with obstructive jaundice, was shown by percutaneous transhepatic cholangiography to have a markedly dilated biliary system and stones within the common bile duct. The stones were removed percutaneously using the transduodenal approach, and an internal drainage catheter was placed. Following the procedure, the patient experienced gastrointestinal bleeding manifested by melanotic stools. Blood-tinged bile was withdrawn from the biliary drainage catheter, leading to the suspicion that the bleeding might be originating from the biliary tract. A Tc-99m red blood cell (Tc-99m RBC) scan was performed to try to designate the biliary tract as the site of bleeding, and to determine if there were any other bleeding sites present. The study demonstrated bleeding from the biliary tract, which was confirmed by angiography and endoscopy. The technique for the detection of gastrointestinal bleeding using Tc-99m RBCs is well described. This case suggests that when doing studies to localize occult bleeding, the liver should be included in the field-of-view to exclude bleeding from the liver.

Aged↗
PubMed1986

Lactic acidosis associated with cirrhosis, hepatoma, hemoperitoneum, and hyperphosphatemia.

A patient with cirrhosis developed hemoperitoneum, lactic acidosis, and hyperphosphatemia in the absence of shock. At post-mortem examination occult multicentric hepatocellular carcinoma eroding the liver capsule was present. The case emphasizes the central role of the liver in lactic acidosis, indicates that hemoperitoneum may precipitate this complication, and documents the association of lactic acidosis and hyperphosphatemia.

Acidosis↗
PubMed1986

Bile duct stones: percutaneous transhepatic removal.

Percutaneous transhepatic intervention for transduodenal removal of biliary stones was performed 38 times in 34 patients with obstructive jaundice, biliary colic, and cholangitis. The technique entailed the percutaneous transhepatic placement of a modified Dormia basket in the common duct with the flexible tip in the duodenum. The stones were passed into the duodenum and were crushed, or were crushed in the common duct and passed as fragments into the duodenum. In addition to the snare procedure, monooctanoin was used 18 times to dissolve remaining fragments of stone and sludge that could not be snared and passed into the duodenum. The average time for completion of the procedure was 10 days. There were no deaths from the procedure. The complication rate was 21%--probably no greater than would occur with surgery in a similar patient population. The procedure can be performed when endoscopic retrograde cholangiopancreatography and sphincterotomy with stone removal is technically impossible or refused, and in patients who have previously undergone choledochojejunostomy.

Adult↗
PubMed1985

Dominant inheritance of adenomatous colonic polyps and colorectal cancer.

Except in the rare polyposis syndromes, the contribution of heritable factors to the genesis of colorectal cancer and adenomatous polyps is not well understood. We examined the inheritance of susceptibility to colonic polyps and cancer in a large Utah pedigree with multiple cases of common colorectal cancer but no recognizable inheritance pattern among them. Inheritance was clarified, however, by systematic screening for colonic polyps in pedigree members and spouse controls, using flexible proctosigmoidoscopy. One or more adenomatous polyps were found in 21 per cent of family members (41 of 191) but in only 9 per cent of controls (12 of 132) (P less than 0.005). Pedigree analysis was performed with likelihood methods that compared random occurrence of cancer and polyps with autosomal recessive and autosomal dominant patterns of inheritance. The analysis suggested that the observed excess of discrete adenomatous polyps and colorectal cancers was the result of an inherited autosomal dominant gene for susceptibility, rather than an inherited recessive gene for susceptibility or a chance occurrence. This type of inheritance of colorectal polyps and cancer may be more common than previously recognized.

Adult↗
PubMed1985

Erosive arthritis in a patient with amyloid arthropathy.

Amyloid arthropathy is said to be distinguished roentgenographically from rheumatoid arthritis by the absence of joint space narrowing and the absence of articular erosions. We present a patient with multiple myeloma with swelling, stiffness and firm synovial thickening of the wrists, metacarpophalangeal joints and proximal interphalangeal joints whose hand radiographs showed articular erosions of the carpal joints and ulnar styloid and joint space narrowing of the proximal interphalangeal joints and metacarpophalangeal joints. Synovial biopsy of the left wrist showed amyloid deposits with no inflammation. Previous reports of X-ray changes in amyloid arthropathy note preservation of joint spaces or widening. Erosions when noted are of non-articular bone rather than of the articular surface. This is the first case report of erosive articular disease in amyloid arthropathy.

Aged↗
PubMed1985

Chest pain after nontransmural infarction: the absence of remediable coronary vasospasm.

To assess the contribution of coronary vasospasm to chest pain in patients with nontransmural myocardial infarction, we performed a controlled trial of prophylactic antivasospastic therapy. Fifty patients with nontransmural infarction received either nifedipine or placebo in a double-blind randomized trial. Chest pain occurred in 52% of treated patients (38 episodes on 35 days) compared to 48% of control patients (42 episodes on 33 days). Concurrent therapy was comparable in the two groups. Recurrent infarction occurred in 12% and was comparable between groups. Ejection fraction was similar and was unchanged throughout the study in both groups. Logistic regression failed to identify predictors for recurrent chest discomfort. These data indicate that potent antivasospastic therapy does not reduce the incidence of recurrent chest pain or infarction. Thus, remediable coronary vasospasm is not likely to be a major cause of post infarction ischemia in patients with nontransmural infarction.

Aged↗
PubMed1985

Solitary nodular sarcoidosis.

Three patients, each with a solitary lung nodule consisting of sarcoid tissue, are described. With the exception of one case where a submandibular lymph node was palpable, clinical and pathological involvement was limited to the thorax and the prognosis was highly favourable. In spite of atypical features, the absence of other causes of granulomatous inflammation suggests that these patients had sarcoidosis. What factors account for limited granulomatous reaction in this form of sarcoidosis are unknown. Previous use of corticosteroids and an age of over 40 years are two possible causes suggested by these cases.

Adult↗