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Biomedical subjects

L E Smith

Publications and source records attributed to L E Smith.

At least 91 records · Page 5Linked to original sources
PubMed1989

Surgical therapy in ulcerative colitis.

Ulcerative colitis is cured if the colon and rectum are removed. The total proctocolectomy provides the cure, but the ileostomy is not well accepted by patients. Thus, alternatives that provide continence but have an increased morbidity have been introduced. The continent ileostomy (Koch pouch) has a valve created in an ileal pouch which provides continence. Intubation with a catheter is necessary and a flat ostomy is present. A colectomy with ileoproctostomy can be used to salvage the sphincter. Unfortunately, the diseased rectum is spared with its potential for progressive symptoms and cancer. The newest technique is also the most morbid. This procedure requires total colectomy, stripping of the rectal mucosa, formation of an ileal pouch, anastomosis of the pouch to the anus, and placement of a diverting ileostomy to allow complete healing without passage of stool. The failure rate is five to ten per cent, but most young people opt to save the sphincter and preserve their body image.

Colectomy↗
PubMed1988

Characterization of vascular development in the mouse retina.

The murine retina provides an ideal model for the study of vascular development. In this investigation we have examined the development of blood vessels in flat-mounted whole retinas from C57B6 mice ranging from birth to 4 months of age. Basement membrane components of blood vessels were visualized by indirect immunofluorescence with antibodies against type IV collagen and laminin. Endothelial cells (EC) were labeled with a plant lectin, Ricinus communis agglutinin I (RCA), and antibodies against angiotensin converting enzyme. Results show three stages of vascular differentiation. During the first stage (postnatal days P0-P10), vessels develop radially from optic disc to ora serrata within the presumptive nerve fiber layer. In the second stage beginning P4, vessels form within deeper retinal layers. In the third stage beginning P7, a capillary network develops as branches of radial vessels in the nerve fiber layer. The entire vascular system begins as a polygonal network of capillary-like vessels. Selective regression of various segments of these polygons leads to the ultimate arborous pattern of arteries, arterioles, veins, venules, and capillaries seen in the adult. Some individual EC appear to be left behind during this retraction process and pericytes may have a role in determining which vessel segments regress. This combination of flat-mounted whole retinas and probes specific for vascular elements provides an ideal system for the study of retinal vascularization and the characterization of vasculogenesis in general.

Animals↗
PubMed1988

Ophthalmic evaluation of survivors of acute lymphoblastic leukemia.

Eighty-two survivors of acute lymphoblastic leukemia (ALL) had prospective eye evaluations to determine the ocular sequelae of the disease and its treatment. All patients had completed or nearly completed a 25- to 31-month protocol which included either 3.4 or 10.2 g of systemic prednisone/m2 per year and cranial irradiation (total 1800-2800 rad). The mean interval from the end of treatment to the eye examination was 32 months. Only one patient had reduced vision attributable to the ALL. Ocular morbidity attributed to the treatment only included posterior subcapsular cataracts (PSCs) which occurred in 52% of patients. Posterior subcapsular cataracts (PSCs) developed in none of the 15 survivors of acute myelogenous leukemia (AML) examined who had received neither long-term systemic prednisone nor irradiation (P = 0.0006). Eyes with PSC had a median visual acuity of 20/20 (range, 20/15-20/50). The authors conclude that the ocular morbidity from antileukemia treatment programs at our institutions is minimal.

Cataract↗
PubMed1988

Immobilized polyphosphate kinase: preparation, properties, and potential for use in adenosine 5'-triphosphate regeneration.

Polyphosphate kinase (ATP:polyphosphate phosphotransferase; EC 2.7.4.1), partially purified from Escherichia coli, has been immobilized on glutaraldehyde-activated aminoethyl cellulose with a 10% retention of enzymatic activity. The immobilized enzyme can carry out the synthesis of ATP from ADP, using long-chain inorganic polyphosphate as a phosphoryl donor. Chromatographic analyses of the product mixture produced from ADP and [32P]polyphosphate demonstrated that 98% of the 32P was incorporated into ATP, indicating that the immobilized polyphosphate kinase is substantially free from contaminating polyphosphate phosphohydrolase (EC 3.6.1.11), adenosine triphosphatase (EC 3.6.1.4), and adenylate kinase (EC 2.7.4.3). Immobilized polyphosphate kinase loses no activity when stored in an aqueous suspension for 2 months at 5 degrees C or for 1-2 weeks at 25 degrees C. It may be stored indefinitely as a lyophilized powder at -10 degrees C. Michaelis constants for ADP and polyphosphate were determined to be 160 and 120 microM, respectively, for the immobilized enzyme. A small-batch reactor was found to produce ATP linearly with time up to 65% conversion of polyphosphate into ATP and to attain greater than 85% conversion to ATP at equilibrium. The ease of purification and immobilization of E. coli polyphosphate kinase, its storage stability, the purity and yield of its ATP product, and the low values of the Michaelis constants for its substrates make it a highly promising enzyme for ATP regeneration.

Adenosine Triphosphate↗
PubMed1987

High dose carboplatin in the treatment of lung cancer and mesothelioma: a phase I dose escalation study.

Sixteen patients with lung cancer or mesothelioma have been treated with escalating doses of carboplatin. Five patients (10 courses) were given 800 mg/m2, four patients (five courses) 1200 mg/m2 and seven patients (eight courses) 1600 mg/m2. Myelosuppression was the major toxicity encountered. The median duration of grade 4 neutropenia ranged from 1 day (800 mg/m2) to 11 days (1600 mg/m2) and the median duration of grade 4 thrombocytopenia ranged from 1 day (800 mg/m2) to 7 days (1600 mg/m2). The median fall in haemoglobin (Hb) ranged from 2.2 g/l (800 mg/m2) to 3.6 g/l (1600 mg/m2). Nephrotoxicity was encountered at all dosages and was in part, though not entirely, dose related. 2/9 patients receiving 800 mg/m2 and 4/6 of the patients receiving 1600 mg/m2 had a fall in glomerular filtration rate (GFR) greater than 25% but less than 50%. 800 mg/m2 of carboplatin was well tolerated, the performance status in 9/10 (90%) courses being 0-1 (ECOG scale). At 1600 mg/m2 in 6/8 (75%) courses the performance status was 2-4. There was one treatment-related death from neutropenia at this dose level. The severity of nausea and vomiting was not dose related but other toxicities including diarrhoea, alopecia, mild neuropathy and ototoxicity and possible CNS toxicity occurred at doses of 1200 mg/m2 and over. 5/7 patients with small cell lung cancer achieved a complete or partial response to treatment.

Adult↗
PubMed1987

Hemorrhoids. A review of current techniques and management.

Most physicians see many patients with the chief complaint of hemorrhoids. The usual presentation is bleeding with bowel movements and prolapse. Of course, if there are no symptoms, invasive treatment should not be entertained. If the symptoms are due to hemorrhoids, the degree of prolapse should be established in order to guage the treatment. Mild symptoms of first- and second-degree hemorrhoids may be treated by diet modification or a fixation process such as rubber band ligation or infrared photocoagulation. Moderate prolapse as with large second-degree and third-degree hemorrhoids need the more certain fixation of rubber band ligation or an excisional technique. Large third-degree hemorrhoids and fourth-degree hemorrhoids require removal of a portion of the prolapsing tissue to achieve a stronger fixation within the proximal anal canal.

Anal Canal↗
PubMed1986

Ambulatory surgery for anorectal diseases: an update.

More than 90% of anorectal surgery can be done in an outpatient setting. The savings for anorectal procedures in 1982 for inpatient room cost alone could have been almost $200 million. The use of local anesthesia for anorectal surgery enhances patient safety. Ambulatory surgery should be considered whenever anorectal procedures are contemplated.

Abscess↗
PubMed1986

A review of twenty-one rectal mucosectomy and ileal pouch pull through procedures.

Twenty-one patients with chronic ulcerative colitis (CUC) or familial polyposis underwent total colectomy, rectal mucosectomy, ileal pouch formation and anastomosis of the pouch to the dentate line. Eleven (52%) intraoperative problems occurred. No deaths resulted. Ten (48%) postoperative complications were treated without operative intervention. Ten postoperative complications required a minor or major procedure to remedy the problem. The most common major complications were four small bowel obstructions. The only septic complication was a single wound infection. Functional results have been satisfactory with 14 of 19 (74%) having six or fewer bowel movements per day. Most patients do not wear perineal pads either day or night. Only one patient felt his lifestyle had worsened. Seventeen of 19 (90%) patients were satisfied with their result and would choose to have the operation again. Frequent diarrheal stools associated with incontinence was the primary reason for a failure and excision of one pouch. This procedure is becoming the alternative of choice for CUC and polyposis because of the ability to cure the disease as well as preserve anal sphincter function.

Adolescent↗
PubMed1985

Complications of colostomy closure.

A series of 126 colostomy closures was analyzed to evaluate factors contributing to morbidity. There were no deaths, but there was a 33 percent complication rate. Patients with penetrating abdominal trauma and foreign-body rectal perforations had fewer serious complications following colostomy closures than patients with diverticulitis or cancer. No significant difference was found in the anastomotic leak rate, length of surgery or length of hospitalization in patients with sutured or stapled anastomoses. Most patients in this series had end colostomies that required limited resection and anastomoses. Complication rates were comparable with previous series, which consisted predominantly of loop colostomy closures. The incidence of surgical complications was not related to the time interval between colostomy formation and closure. Timing of closure, however, significantly influenced the complication rate in two specific patient groups: patients with intraperitoneal colon perforation at the initial procedure when closure was performed within four weeks, and patients with surgical complications at the time of colostomy creation if they underwent closure within eight weeks. Early closures in patients still recovering from colostomy complications were associated with the highest incidence of anastomotic leak. Wound infections at stoma sites were decreased by leaving the skin open. The average hospitalization was 11.1 days for patients without complications, 15.5 days for those with wound infection, 18.5 days for patients with ileus, and 20.4 days for patients with anastomotic leaks. This study illustrates that the optimal time for colostomy closure must be determined on an individual basis. The morbidity can be minimized by delaying closure in specific groups of patients for one to two months. Delaying closure for an arbitrary time interval in all patients, however, is not warranted.

Adolescent↗
PubMed1985

Current status of sphincter-saving operations for chronic ulcerative colitis.

When surgery is demanded by the course of a patient with ulcerative colitis, the sphincter mechanism can be spared. The straight ileoanal anastomosis without a reservoir has not been satisfactory for adults because of frequent diarrheal stools. The ileorectal anastomosis has the advantage of minimal morbidity, but the patient is not totally cured, because the diseased rectum is still in place. The pouch pull-through procedure has an increased morbidity, but the patient is cured of ulcerative colitis. The anastomotic stricture rate is 7% to 15% and the failure rate, 2% to 6%. Inflammation of the pouch or reservoir occurs in 5% to 19%. There have been no deaths in the reviewed series. As the details of the pouch pull-through procedure are refined, this operation will become the choice for treatment of ulcerative colitis.

Adult↗
PubMed1985

Symposium on outpatient anorectal procedures. Flexible fiberoptic sigmoidoscopy: an office procedure.

Patients who had benign polyps and cancers were studied retrospectively to define whether use of the 60-cm flexible sigmoidoscope would markedly improve the diagnostic yield over the 25-cm rigid sigmoidoscope. Of the polyps found, 48% could have been seen by the rigid sigmoidoscope and 85% by the flexible sigmoidoscope. Cancers were within reach of digital examination in 21%, of the rigid sigmoidoscope in 38% and of the flexible sigmoidoscope in 60%. This verifies the greater diagnostic yield by the flexible sigmoidoscope. In 211 asymptomatic patients who underwent flexible fiberoptic sigmoidoscopy, the scope reached to 25 cm in all and to 50 cm in 75%. The average time required for the examination was 4.9 minutes. Of these patients, who had also undergone rigid sigmoidoscopy previously, 76% preferred the flexible scope, 18% preferred the rigid scope and 6% could tell no difference. The yield of neoplasms was 4% in the distal 25 cm of the colon and rectum, but an additional 8% were found in the sigmoid colon. This review supports the need for flexible sigmoidoscopy in the office as a screening tool for detection of polyps and early diagnosis of cancer in the asymptomatic patient over 40 years of age. Technique, costs and complications are discussed.

Ambulatory Care↗
PubMed1985

Hemodynamic and plasma catecholamine responses to epinephrine-containing perianal lidocaine anesthesia.

Despite the frequent use of large volumes (30-40 ml) of epinephrine-containing local anesthetic solutions for ano-rectal surgery, little is known about the anesthetic-induced hemodynamic consequences. Therefore, we measured the heart rate, blood pressure, and plasma catecholamine (norepinephrine and epinephrine) responses to the perianal injection of 40 ml of 0.5% lidocaine alone (n = 8) or 0.5% lidocaine with 1:200,000 epinephrine (n = 10) in 18 healthy adults undergoing outpatient ano-rectal surgery. The mean +/- SEM plasma epinephrine concentration increased from a baseline of 42 +/- 7 pg/ml to a peak of 622 +/- 94 pg/ml 4 min after injection of epinephrine-containing anesthetic (P less than 0.001), whereas lidocaine alone increased the mean plasma value from 36 +/- 9 pg/ml (baseline) to only 69 +/- 16 pg/ml (not significantly different) at its peak. Despite the increases in plasma epinephrine levels in the group receiving epinephrine-containing anesthesia, no changes in blood pressure, heart rate, or plasma norepinephrine levels were observed. Given the advantages (including prolongation of the duration of anesthesia) of adding epinephrine to perianal local anesthetics, our data support its safe use in healthy adults.

Adult↗
PubMed1984

A retinohypothalamic pathway in man: light mediation of circadian rhythms.

It has been proposed that, in animals, a retinohypothalamic pathway exists which mediates the synchronization of the diurnal light-dark cycle with the central neural components regulating endogenous rhythms. There have been numerous anatomic, physiologic and behavioral investigations to substantiate this proposed connection in experimental animals. Morphologic investigation of a retinohypothalamic tract in man has awaited the development of a technique capable of axonal tracing in the human brain. The paraphenylenediamine method was applied to 7 post-mortem human brains. Degenerated axons were found in the suprachiasmatic nuclei of the hypothalamus in each of the 4 patients who had incurred prior optic nerve damage. The retinosuprachiasmatic pathway may be the anatomical substrate for the integration of retinal light information with endogenous rhythms in man.

Aged↗
PubMed1983

Management of perforation due to colonoscopy.

Six patients who underwent emergency laparotomy for perforations secondary to colonoscopy or polypectomy are described. Three patients had the laceration closed primarily, two required colostomy, and one needed resection. When contamination is minimal and the colon is mechanically prepared, primary closure without diversion is the treatment of choice. Colostomy is rarely indicated and may lead to increased morbidity, in view of the need for closure. However, resection should be considered if suspicion of carcinoma is great. Factors that contribute to perforation include sedation, forceful introduction of the colonoscope, inadequate equipment for hemorrhage control, and prolonged application of electrocoagulation to the colonic wall.

Colonoscopy↗
PubMed1983

Subtotal colectomy for obstructing carcinoma of the left colon.

This retrospective review of seven patients with completely obstructing cancers of the left half of the colon, in addition to other reports in the literature, suggests that subtotal colectomy with primary ileal proctostomy may be the treatment of choice for those lesions that are technically resectable and located high enough to permit an intraperitoneal ileal proctostomy. The morbidity and mortality is less than that seen with the staged approach and the length of hospitalization is shorter. By eliminating a second or third hospitalization and a temporary colostomy, palliation is better in those patients who ultimately die from recurrent cancer. Furthermore, those patients resected for cure may have increased rates of long-term survival.

Aged↗