Biomedical subjects

M E Stark

Publications and source records attributed to M E Stark.

24 records · Page 2Linked to original sources

PubMed1991

Effect of nitric oxide on circular muscle of the canine small intestine.

1. Experiments were designed to determine in circular muscle of the canine jejunum whether exogenous nitric oxide (NO) mimics the non-adrenergic, non-cholinergic inhibitory junction potential (NANC IJP), and whether changes in the availability of endogenous NO affects IJP amplitude. 2. Mechanical and intracellular electrical activity were recorded simultaneously from circular muscle of the canine jejunum. Electrical field stimulation evoked NANC IJPs and inhibited spontaneous contractions. 3. Infusions of NO solutions evoked immediate dose-dependent and transient hyperpolarizations and transiently inhibited spontaneous contractions. NO-evoked hyperpolarizations were unaffected by atropine, propranolol, phentolamine and tetrodotoxin. 4. The maximum IJP amplitude and the maximum amplitude of NO-evoked hyperpolarization were similar. 5. NG-Mono-methyl-L-arginine (L-NMMA), which inhibits synthesis of NO from L-arginine, reduced IJP amplitudes but did not reduce the response to exogenous NO. L-Arginine, but not D-arginine, reversed the effect of L-NMMA on IJP amplitude. 6. Oxyhaemoglobin, which binds and inactivates NO, reduced IJP amplitude and abolished the response to exogenous NO. 7. Exogenous NO mimicked the effects of NANC inhibitory input. Reducing the availability of endogenous NO reduced NANC inhibitory input. 8. It was concluded that NO mediates NANC neural inhibition and may act as a NANC inhibitory neurotransmitter in the canine jejunum.

Animals↗

PubMed1987

Fatal acute tumor lysis syndrome with metastatic breast carcinoma.

A 53-year-old woman presented with an extensively metastatic and rapidly growing breast adenocarcinoma, markedly elevated lactate dehydrogenase, and mildly elevated blood urea nitrogen. She received 5-fluorouracil, doxorubicin, and cyclophosphamide. Eighteen hours after chemotherapy she was noted to have hyperuricemia, hyperkalemia, hyperphosphatemia, hypocalcemia, and acute renal failure. She experienced cardiac arrest and died 72 hours after receiving chemotherapy. A postmortem liver biopsy revealed adenocarcinoma undergoing necrosis. This case represented the acute tumor lysis syndrome that occurred after chemotherapy of breast carcinoma. Patients with metastatic breast carcinoma and similar presentations should be considered for prophylactic therapy with allopurinol and hydration before chemotherapy.

Adenocarcinoma↗

PubMed1987

The initial electrocardiogram during admission for myocardial infarction. Use as a predictor of clinical course and facility utilization.

The first electrocardiogram obtained on presentation for suspected myocardial infarction was examined for its usefulness in predicting clinical course and facility use. We studied 221 patients consecutively admitted to a nonuniversity hospital coronary care unit. High-risk patients were identified if the electrocardiographic diagnoses included myocardial infarction, ischemia, left ventricular hypertrophy, left bundle-branch block, or paced rhythm. These 63 patients (29% of total) had significantly greater incidences of serious events, need for procedures, and death than low-risk patients whose initial electrocardiograms did not carry the above diagnoses. Patients with a low-risk initial electrocardiogram may not require the facilities of a coronary care unit and perhaps could be safely observed in an intermediate care area. However, many hospitals do not have an intermediate care facility available, and in those that do, daily costs may not be markedly different than for treatment in a coronary care unit. Whether these low-risk patients could be safely treated in general medicine beds, where potential cost savings would be much greater, is unknown.

Coronary Care Units↗

PubMed1980

Routine operative cholangiography with cholecystectomy.

Four hundred and forty patients who underwent cholecystectomy and routine operative cholangiography were reviewed. False-positive and false-negative examination were 3.8 and 0.2 per cent, respectively. Unsuspected common duct stones were found 0.9 per cent of the time by cholangiography. The yield of common duct exploration was 63.8 per cent. Operative cholangiography spares at least two-thirds of the patients with clinical indications of choledocholithiasis unnecessary common duct explorations. The yield of operative cholangiography in patients with no clinical indication of choledocholithiasis is extremely low, and the cost-to-benefit ratio of routine operative cholangiography is high. Operative cholangiography should be used prior to common duct exploration for any clinical suspicion of common duct pathology. Routine operative cholangiography is not indicated for those patients with no clinical indication of common duct pathology.

Cholangiography↗

PubMedDate not supplied

Clinical features and endoscopic management of Dieulafoy's disease.

The experience of a specialized management team using urgent endoscopy in the management of acute gastrointestinal bleeding from Dieulafoy's disease is presented. Dieulafoy's disease was found in 19 of 1124 consecutive patients with upper gastrointestinal bleeding. Most patients with Dieulafoy's disease were elderly men with severe acute upper gastrointestinal hemorrhage. Endoscopic diagnosis was possible in all patients, but required multiple endoscopies in 37%. The lesions were in the proximal stomach (79%) and duodenal bulb (21%). Endoscopic therapy included epinephrine injection, then heater probe coagulation in 17 patients, bipolar electrocoagulation in 1, and Nd:YAG laser photocoagulation in 1. Endoscopic therapy was successful in 18 patients (95%); one patient had successful surgery after endoscopic therapy failed. There were no deaths due to bleeding and no endoscopic complications. Dieulafoy's disease is an unusual cause of acute gastrointestinal bleeding. Endoscopic diagnosis is sometimes difficult, but primary endoscopic therapy is safe, successful, and should be attempted.

Aged↗

PubMedDate not supplied

Metastasis of head and neck carcinoma to the site of percutaneous endoscopic gastrostomy: case report and literature review.

BACKGROUND: Patients with head and neck cancer often need a percutaneous endoscopic gastrostomy to provide adequate nutrition because of inability to swallow after tumor radiation therapy. However, metastasis of the original tumor to the gastrostomy exit site may occur. METHODS: We describe the case of a 61-year-old man with stage III (T2 N1) squamous cell carcinoma of the tongue in whom a PEG tube was placed to circumvent anticipated difficulties in swallowing after radiation therapy. We also compare this case with similar cases in the literature. RESULTS: Soreness and erythema near the gastrostomy site reported by the patient were diagnosed as cellulitis, and two courses of antibiotic treatment were prescribed. However, a biopsy showed that the original squamous cell carcinoma had metastasized to the gastrostomy exit site. The "pull" method of tube placement had been used in this patient and in all 19 cases of metastasis reported in the literature. CONCLUSIONS: Metastatic cancer should be considered in patients with head and neck cancer who have unexplained skin changes at the gastrostomy site. Our experience with this case and review of the literature indicate that, in patients with head and neck cancer, "pull" procedures for placement of gastrostomy tubes may induce metastasis by direct implantation of tumor cells because of contact between the gastrostomy tube and tumor cells. Methods of tube insertion that avoid such contact are preferred.

Carcinoma, Squamous Cell↗