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Biomedical subjects

C E Rubin

Publications and source records attributed to C E Rubin.

At least 55 records · Page 3Linked to original sources
PubMed1977

Endoscopic laser treatment. II. Comparison of the efficacy of high and low power photocoagulation in control of severely bleeding experimental ulcers in dogs.

The coagulative efficacy of a "high power" argon laser which delivers 6.5 +/- 1.0 w was compared to that of a "low power" argon laser which delivers 1.0 +/- 0.1 w. The wave-guide angle of divergence was 8 degrees. For the high power laser, the distance between the wave-guide tip and the mucosa varied from 1.0 to 1.5 cm with a delivered power density range of 160 to 487 w per cm2. For the low power laser, the distance between the tip and mucosa varied from 0.7 to 1.3 cm with a power density of 35 to 146 w per cm2. Group A consisted of acute experiments in 6 heparinized dogs in which 51 standard-sized acute gastric ulcers extending into the submucosa were made at laparotomy via a large gastrotomy. Ulcer bleeding rates were quantified into three categories of severity. Within each category, ulcers were randomized to high power, low power, or untreated control. All 19 low power-treated ulcers and 16 untreated controls continued bleeding; 13 of 16 high power-treated ulcers stopped bleeding completely. Representative ulcers were examined histologically. Group B consisted of chronic experiments on 31 ulcers in 7 unheparinized dogs. These ulcers were either treated with high power or left as untreated controls. Dogs were killed and the ulcers were examined histologically at 7, 14, and 28 days. Only rarely did the laser injury penetrate into the muscularis externa. There were no perforations. By 14 days, all lesions were covered with normal surface epithelium. These data encourage further development of congruent to 7.0 w argon laser photocoagulation for eventual clinical use in man.

Animals↗
PubMed1977

Effect of bisacodyl on the structure and function of rodent and human intestine.

The effect of bisacodyl on intestinal structure and function was investigated. Net water transport was measured under steady state conditions in vivo during single pass infusions of rodent and of human intestinal segments. Each segment served as its own control. Bisacodyl inhibited water absorption in rat jejunum, ileum, and colon. The degree of inhibition was linearly related to the logarithm of the bisacodyl concentration over the range of 0.05 to 2.0 mg per 100 ml. In human jejunal segments, bisacodyl, 1 mg per 100 ml, caused net water secretion. Bisacodyl, 5 mg every 6 hr, increased ileostomy output by 15% when it was fed to 5 patients with established ileostomies. By light microscopy, bisacodyl, 2 mg per 100 ml, erased cytoplasmic and nuclear detail within surface absorptive cells of rat intestine. By electron microscopy, the involved cells contained sparse and abnormal cytoplasmic organelles and nuclei which were deficient in chromatin. These results suggest that the laxative effect of bisacodyl is related to its ability to inhibit intestinal water absorption. Reduced absorption may be secondary to changes in surface absorptive cells.

Animals↗
PubMed1977

Human rectal mucosa: proctoscopic and morphological changes caused by laxatives.

To determine whether laxatives alter the proctoscopic and morphological appearances of the human rectum, 10 normal subjects were studied prospectively, and the following manipulations were assessed in a randomized, blinded manner: no treatment; oral mannitol to induce diarrhea; isotonic saline enema; Fleet's Phospho-Soda enema; and bisacodyl (Dulcolax), 10 mg, by enema or suppository. The rectal mucosa after mannitol-induced diarrhea, or after saline enema could not be distinguished from untreated rectum by proctoscopy, light microscopy, or scanning electron microscopy. Fleet's enema, and bisacodyl invariably changed proctoscopic appearances, and frequently altered light and scanning microscopic aspects. Both Fleet's enema and bisacodyl caused sloughing of surface epithelium. In addition, bisacodyl decreased the uptake of hematoxylin and eosin by crypt epithelial cells so that the affected cells had a partially erased appearance (16 of 25 biopsies examined by light microscopy). The lamina propria of 3 of these 25 biopsies contained polymorphonuclear cells. Transmission electron microscopy revealed that the abnormal crypt epithelial cells contained fewer cytoplasmic organelles and less nuclear chromatin. All lesions resolved within 7 days. Fleet's enema and bisacodyl by rectum may mislead the proctologist and the pathologist by altering normal rectal mucosa.

Bisacodyl↗
PubMed1976

The new look into the gastrointestinal tract.

Esophagogastroduodenoscopy has proved to be the most accurate method of diagnosing disese of the upper gastrointestinal tract. Endoscopic technics already are being employed for the treatment of gastric polyps. Experimental work on endoscopic treatment of upper gastrointestinal bleeding is under way in several medical centers. A variety of methods are being tested: laser photocoagulation, suture clip placement and the use of bioco+mpatible tissue glues. Endoscopic retrograde cholangiopancreatography now is established as a useful technic in the diagnosis of biliary tract disease. Its diagnostic usefulness in the pancreas is confined to certain diseases in which it is desirable to determine the need for operative intervention. The initial success of endoscopic papillotomy and stone extraction promises further future therapeutic uses for ERCP. Colonoscopy may well prove to be the most useful of the gastrointestinal endoscopic methods. It is particularly helpful in diagnosing colonic cancer, in determining the source of occult colonic bleeding and in providing information regarding idiopathic colonic inflammatory disease. The success of polypectomy indicates the possibility of substituting endoscopic treatment for invasive surgery. Laparoscopy in conscious patients is a well-established technic that is useful in gastroenterology, hepatology, oncology and gynecology. Its usefulness has long been appreciated in other countries and the method merits wide use in the United States. Endoscopy is a rapidly changing and evolving field. This monograph has attempted to outline the current state of the art, but many changes are expected in the next 5-10 years.

Biliary Tract Diseases↗
PubMed1976

High power argon laser treatment via standard endoscopes. I. A preliminary study of efficacy in control of experimental erosive bleeding.

With minimal transmission loss a high power argon laser (10 w) was coupled to a waveguide consisting of a flexible, single, coated, quartz fiber encased in a protective polyethylene tube. This waveguide can be passed down the biopsy channel of any standard fiberoptic endoscope. An aiming light improves accuracy. Safety devices were developed to protect the subject and the operator. Each of 8 heparinized mongrel dogs had three superficial erosions created endoscopically in the fundal gland mucosa by a jet of warm 0.1 N HC1. In each animal two lesions were photocoagulated with the laser and the third was left as a control. The animals were killed at 0, 4, 7, 10, and 14 days, and the erosions were examined histologically. By 14 days all lesions were covered by normal surface epithelium. Parietal and chief cells had returned to untreated erosions at 14 days but not to all lasered lesions. Only rarely did the lasered lesions penetrate through the muscularis mucosae into the submucosa. High power argon laser photocoagulation is now feasible through standard endoscopes. These data are sufficiently promising to encourage further evaluation of laser photocoagulation in a variety of animal models.

Animals↗
PubMed1976

Overwhelming watery diarrhea associated with a cryptosporidium in an immunosuppressed patient.

A 39-year-old man with severe bullous pemphigoid developed overwhelming diarrhea after 5 weeks' treatment with 150 mg of cyclophosphamide and 60 mg of prednisolone daily. Jejunal and ileal biopsies showed severe mucosal injury and tiny 2- to 4-mu organisms on the epithelial surfaces. Similar organisms were seen in smears of jejunal fluid. Electron microscopic examination of jejunal biopsies showed these spherical bodies to be trophozoites, schizonts, microgametocytes, and macrogametocytes typical of the genus Cryptosporidium. Diarrhea resolved 2 weeks after discontinuation of cyclophosphamide and coincided with disappearance of Cryptosporidia from the jejunal biopsies. Immunosuppression may have predisposed this patient to cryptosporidial diarrhea. Cryptosporidiosis is another infection which can be diagnosed by small bowel biopsy. When immunosuppressed patients develop severe diarrhea, opportunistic infection with this and other organisms should be considered as the possible cause.

Adult↗
PubMed1976

A reproducible animal model of acute bleeding ulcer-the "ulcer maker".

An instrument has been developed which creates an experimental model of an acute bleeding gastric ulcer. The diameter and depth of these gastric ulcers are reproducible. The instrument can be used endoscopically or at laparotomy. Using this ulcer model nonsurgical modalities for the treatment of upper gastrointestinal bleeding can be compared in a controlled manner. This standard experimental model may also facilitate comparison of results among different research groups.

Animals↗
PubMed1975

Morphological and functional effects of bile salts on rat colon.

By correlating morphological observations with quantitative measurements of net water transport, we determined whether bile salts altered colonic absorptive cells. Epithelial alteration was equivocal and water absorption was uninhibited during infusions of 1 mM deoxycholate or of concentrations of taurocholate less than 10 mM. In contrast, 3 mM deoxycholate and greater than 10 mM taurocholate caused severe altertion of colonic epithelium and inhibited water absorption. These studies suggest that bile salts in the low concentrations normally found within the colon have little effect on colonic structure or water absorption. On the other hand, abnormally high concentrations of bile salts do alter colonic mucosal structure and function.

Animals↗
PubMed1971

Synthesis and transport of lipoprotein particles by intestinal absorptive cells in man.

The site of synthesis and some new details of lipoprotein particle transport have been demonstrated within the jejunal mucosa of man. In normal fasting volunteers, lipoprotein particles (88%, 150-650 A diameter) were visualized within the smooth endoplasmic reticulum and Golgi cisternae of absorptive cells covering the tips of jejunal villi. Electron microscopic observations suggested that these particles exited through the sides and bases of absorptive cells by reverse pinocytosis and then passed through the extracellular matrix of the lamina propria to enter lacteal lumina. When these lipid particles were isolated from fasting intestinal biopsies by preparative ultracentrifugation, their size distribution was similar to that of very low density (S(f) 20-400) lipoprotein (VLDL) particles in plasma. After a fatty meal, jejunal absorptive cells and extracts of their homogenates contained lipid particles of VLDL-size as well as chylomicrons of various sizes. The percentage of triglyceride in isolated intestinal lipid particles increased during fat absorption. Our interpretation of these data is that chylomicrons are probably derived from intestinal lipoprotein particles by addition of triglyceride.

Biological Transport↗