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Biomedical subjects

L W Martin

Publications and source records attributed to L W Martin.

At least 19 recordsLinked to original sources
PubMed2000

Current management of colorectal liver metastases.

Colorectal cancer metastatic to the liver represents an uncommon situation in surgical oncology in which metastasectomy can effect longevity and may lead to cure. Liver resection can be done safely and has drastically improved 5-year survival rates to upwards of 35%, but only a minority of patients is eligible. Advances in imaging techniques facilitate detection of metastases and improve patient selection. For unresectable patients, and as an adjunct to resection, local disease control may be achieved with cryosurgery, radiofrequency ablation, or regional chemotherapy delivered by way of infusion through the hepatic artery. Areas of ongoing investigation include regional gene therapy and interference with tumor growth by inhibition of angiogenesis.

Adenocarcinoma↗
PubMed1993

Growth patterns of human neuroblastoma xenografts and their relationship to treatment outcome.

BACKGROUND: Several investigators have reported the ability to establish xenografts in nude mice from children with neuroblastomas, but a correlation of prognosis with this establishment and the growth patterns of the neuroblastomas has not been reported. METHODS: Tumor specimens from 58 children with neuroblastomas were heterotransplanted into BALB/c nude mice. In 34 patients, heterotransplantation was done before therapy; in 24 patients, tumors were obtained after at least one course of chemotherapy or radiation therapy. The histology, cytogenetics, and growth characteristics of serial passages of the xenografts were studied. RESULTS: The engraftment rate was 34%. Neuroblastomas with diploid chromosome numbers did not engraft. Chromosomal abnormalities involving 1p were seen in more than 50% of the xenografts. Cytogenetic features were retained between original tumors and resultant xenografts. Xenografts could be established only from tumors with unfavorable histology, as defined by Shimada classification criteria. The histology of each xenograft line was strikingly similar, and each was highly undifferentiated. Engraftment rates, doubling times, and lag times did not vary appreciably between xenografts established from treated tumors compared with xenografts established from untreated tumors. There was no correlation between doubling or lag times and prognosis. Patients whose tumors engrafted had only a 5% 3-year survival rate. CONCLUSIONS: From these results, it appears that successful engraftment is the most important prognostic indicator for patients with neuroblastomas. Because of the commonality of the histologic features and the stability of the tumor clones from patients before and after heterotransplantation, these xenografts may be useful as an in vivo model for studying drug resistance and for designing treatment regimens.

Animals↗
PubMed1993

Staged repair improves outcome of high-risk premature infants with esophageal atresia and tracheoesophageal fistula.

Twenty-five high-risk premature infants weighing less than 2,000 g at birth (Waterson class C), were treated for esophageal atresia (EA) and tracheoesophageal fistula (TEF). If four patients with associated Trisomy 18 are excluded for whom definitive surgery was denied, 17 of 21 patients (81%) survived. Of significance is that 14 patients with EA and TEF underwent initial gastrostomy tube placement followed by either primary anastomosis or staged repair, depending on clinical status. Four of these infants with distal TEF who were considered low risk underwent a primary anastomosis with 100% survival. However, 3 of these 4 patients developed significant postoperative complications and 2 required subsequent Nissen fundoplication (50%). Ten reached at least 2,000 g in weight with 70% survival. In this group 3 neonates died before the definitive repair could be performed. Of the 7 who survived, only 2 incurred postoperative complications and only 1 patient required Nissen fundoplication (14%). Five other patients were found to have EA without TEF and underwent staged repair with 100% survival. Finally, one additional patient with H-type TEF underwent transcervical ligation and another with a congenital esophageal stenosis died of intracerebral hemorrhage prior to the institution of surgical therapy. Although the number in this series are small, these findings suggest that premature infants with EA and TEF incur a lesser morbidity when treated by a staged repair versus a primary anastomosis.

Comorbidity↗
PubMed1993

Extended myectomy-myotomy. A therapeutic alternative for total intestinal aganglionosis.

OBJECTIVE: That total intestinal aganglionosis (extended Hirschsprung's disease) is uniformly incompatible with life as reported in 1985, is challenged by this series of patients treated over the last 7 years with an alternative therapy, extended myectomy-myotomy of the small bowel. SUMMARY BACKGROUND DATA: A total of 16 neonates worldwide presented with intestinal obstruction secondary to total (extending to the stomach) or near total (to 40 cm of jejunum) intestinal aganglionosis confirmed at one or more leveling operations. METHODS: A patient questionnaire was answered by the surgeon of all 16 patients. RESULTS: The sex distribution was eight boys and eight girls. The definitive operation included extending an antimesenteric myectomy-myotomy from the ganglionic-aganglionic transition zone for variable lengths, the operative design being to create sufficient small bowel length to support life (40-cm minimum, total small bowel maximum). The myectomized bowel was terminated as an end-stroma or as an isolated jejuno-ileal segment. Ten of 16 patients have survived (62.5%) whose length of ganglionated bowel varies from 0 to 40 cm (mean, 12.4 cm; median, 6.0 cm). Six patients have died from 1 to 33 months after operation (mean, 9.5 months; median, 5.0 months) of gut-induced infection (n = 5) and respiratory failure (n = 1); their ganglionated bowel length was similar to survivors (range, 0-26 cm; mean, 9.2 cm; median, 8.0 cm). Of the 16 patients, 15 have received enteral nutrients through the myectomized bowel. Of ten survivors, strikingly two are totally gut nourished (2 cm, 7-cm length of ganglionated bowel), six receive from 1/5 to 4/5 of total calories enterally, and one receives minimal enteral feeding. CONCLUSIONS: From these patients we have learned that (1) extended myectomy-myotomy relieves the obstruction of extended Hirschsprung's disease; (2) aganglionic bowel after extended myectomy-myotomy acts as a passive conduit for proximally propulsed nutrients; and (3) aganglionic bowel after extended myectomy-myotomy undergoes adaptive change and is capable of absorbing life-supporting nutrients. These data demonstrate extended myectomy-myotomy to be a therapeutic option for otherwise fatal extended Hirschsprung's disease, either as a potentially definitive therapy or as a putative bridge to intestinal transplantation.

Female↗
PubMed1993

Current surgical management of patients with chronic ulcerative colitis.

This report consists of a review of an experience with total colectomy with mucosal proctectomy and neorectal reservoir for pediatric patients with ulcerative colitis. The entire experience includes 221 patients, with 73 patients < 21 years of age. Fifty-six consecutive surviving pediatric patients, all > 1 year after operation, have been studied with 100% follow-up evaluation for up to 17 years after operation. Fifty (89%) are leading normal lives with an acceptable stool frequency and complete continence. A number of postoperative complications have been encountered that are of particular concern to the pediatric gastroenterologist. The most distressing finding has been the subsequent diagnosis of Crohn's disease in most of the patients whose postoperative course was unsatisfactory. This underscores the need for a more accurate means of differentiating ulcerative colitis from Crohn's colitis before advising surgery.

Adolescent↗
PubMed1993

The pull-through procedure: technical factors in influencing outcome, with emphasis on pouchitis.

BACKGROUND: The purpose of the study was to review those features that we believed to be critical to the successful performance of the ileal pouch-anal anastomosis, or pull-through, procedure, and specifically the complication of pouchitis. METHODS: The charts of 205 patients who successfully underwent ileal pouch-anal anastomosis procedure were reviewed. No follow-up was available in five patients; therefore, the basis of this report and its analysis was based on 200 consecutive procedures in which at least two of the three surgeons participated. Particular emphasis was placed on continence, particularly nighttime continence. The incidence of pouchitis, either a single episode or intermittent episodes, was surveyed. Particular attention was paid to the level of rectal mucosectomy and anastomosis at the top of the columns of Morgagni, thus retaining the transitional zone. RESULTS: Only 5% of patients were incontinent in the absence of pouchitis. Twenty-five patients (13%) wore a pad at night, but only nine (5%) wore a pad during the day. Of those patients with pouchitis, 6% (12) have had a single episode and 12% (23) were intermittently on medication. Therapy of pouchitis was usually carried out with ciprofloxacin 500 mg by mouth everyday or twice a day. CONCLUSIONS: Ileal pouch-anal anastomosis is an excellent procedure, provided technical details are adhered to. Satisfactory outcome with respect to nighttime continence can be achieved with rectal mucosectomy with minimal manipulation and retaining the transitional epithelium, performing the pouch anastomosis at the top of the columns of Morgagni. The incidence of pouchitis is disappointing but need not be inhibiting of either patients or carrying out this life-saving procedure in patients with ulcerative colitis and familial polyposis.

Adolescent↗
PubMed1993

Long-term evaluation of the endorectal Soave operation performed for ulcerative colitis or polyposis in the pediatric patient.

BACKGROUND: A follow-up study was conducted to evaluate the late results of the operation that we have performed for ulcerative colitis and polyposis during the past 25 years. METHODS: Sixty-seven consecutive patients less than 21 years of age who underwent a standard operation for ulcerative colitis or polyposis performed by or under direct supervision of one surgeon were included in the follow-up study 2 to 15 years after operation. RESULTS: The 11 patients with polyposis all had "excellent" results. Of the 56 patients with ulcerative colitis, results were "good" or excellent in 48. Of the eight patients with less than good results, one died of complications of preexisting muscular dystrophy; four, or possibly six, had Crohn's disease. Presumably the original disease was Crohn's colitis instead of ulcerative colitis. CONCLUSIONS: The results of the study suggested that this operation was not appropriate for Crohn's disease and underscored the importance and the difficulties of differentiating the two conditions, if they are indeed separate entities.

Adenomatous Polyposis Coli↗
PubMed1991

Impedance measurement of absolute blood flow using an angioplasty catheter: a validation study.

An angioplasty catheter was developed to allow measurement of absolute coronary blood flow during interventional procedures. This method uses electrical impedance changes induced by a 0.5 ml bolus of 5% dextrose solution and indicator-dilution principles. The indicator is injected through a port located just proximal to the dilating balloon and the resulting changes in blood impedance are measured by electrodes at the catheter tip. Excellent linear correlations were found between known flow in 2 to 4 mm to diameter plastic tubes and catheter measurements (r = 0.99) and between timed collection canine femoral artery flow and catheter measurements (r = 0.97). Final validation was performed in canine coronary arteries using electromagnetic flowmeter data as the standard (r = 0.94). Thus accurate clinical determination of absolute coronary blood flow can be accomplished using this relatively inexpensive and simple catheter technique.

Angioplasty, Balloon, Coronary↗
PubMed1991

Dexamethasone facilitates release of the neuropeptide alpha-MSH.

alpha-Melanocyte stimulating hormone (alpha-MSH) has important host defense properties, in part similar to those of corticosteroids. Previous research suggests that secretion of alpha-MSH and of ACTH are controlled separately. The relationship between release of alpha-MSH and the activity of the hypothalamic-pituitary-adrenal axis in the rabbit was examined by monitoring changes in circulating alpha-MSH, ACTH, and corticosterone in response to endotoxin and corticotropin-releasing hormone (CRH), both with and without dexamethasone pretreatment. Endotoxin (1 microgram/kg IV) did not cause alpha-MSH release, but it did increase plasma concentrations of ACTH and corticosterone. Similarly, CRH (1 and 10 micrograms/kg IV) did not affect plasma alpha-MSH, whereas it stimulated ACTH and corticosterone release. Dexamethasone pretreatment abolished the responses of ACTH and corticosterone to either stimulus and did not modify circulating alpha-MSH after CRH. In contrast, dexamethasone pretreatment did result in a significant increase in plasma alpha-MSH after a dose of endotoxin that was ineffective alone. These data indicate that corticosteroids can facilitate the release of alpha-MSH, a powerful anti-inflammatory hormone. Since corticosteroids are released with certain challenges, this facilitatory activity may be important to the host response.

Adrenocorticotropic Hormone↗
PubMed1991

Pediatric bicycle trauma.

Bicycle-related trauma is a serious pediatric problem. Serious injuries and even fatalities can occur, and care must be taken to avoid undertreating these patients. In an effort to further define the problem, 201 consecutive patients admitted for bicycle trauma were reviewed. The patients ranged in age from 3 to 16 years and 76% (153/201) were male. Head trauma was the most common admission diagnosis (99/201; 49%). Fourteen per cent (28/201) were admitted to the Intensive Care Unit and 23% (47/201) required an operative procedure. The average hospital stay was 3 days; however, patients who were admitted at least 24 hours after injury had an average hospital stay of 7 days.

Adolescent↗
PubMed1990

Cardiac contusion in pediatric patients with blunt thoracic trauma.

To investigate the prevalence of myocardial contusion associated with blunt chest trauma in the pediatric age group, all patients admitted to our institution during a 6-month period with blunt thoracic trauma severe enough to produce a pulmonary contusion or rib fracture were prospectively evaluated. Cardiac evaluation was undertaken, including a multiple-gated acquisition (MUGA) cardiac scan, serial electrocardiograms (ECG), and serum creatine phosphokinase (CPK) and CPK isoenzymes. Seven patients, ranging in age from 2 1/2 to 18 years, with rib fractures or pulmonary contusion by chest roentgenograph were identified. One patient was injured as a passenger in a motor vehicle accident, five were struck by automobiles as pedestrians, and one sustained traumatic asphyxia when a car, supported by a jack, fell on his chest. All had at least one other major organ system injured. All patients had pulmonary contusions as determined by chest radiograph, and two had associated rib fractures. In 43% (three of seven) of patients, a significant cardiac contusion was identified, defined by abnormal right or left ventricular wall motion and a decreased ejection fraction on MUGA scan, and confirmed by an increase in cardiac enzymes and isoenzymes. However, in contrast with adults, no patients had ECG abnormalities. This limited series suggests that cardiac contusion may occur frequently in pediatric patients who have suffered from blunt thoracic trauma significant enough to result in pulmonary contusion. An MUGA scan provides a rapid, noninvasive assessment of cardiac damage in this setting. Further studies will be required to determine the clinical significance and long-term consequences of traumatic myocardial damage in the pediatric population.

Accidents, Traffic↗
PubMed1990

High apical insertion of the right diaphragm in an infant with right-sided Bochdalek diaphragmatic hernia.

We report the case of a newborn full-term infant who presented to our service on the first day of life with a right-sided Bochdalek congenital diaphragmatic hernia associated with a high apical insertion of the right hemidiaphragm at the level of the second rib. This resulted in incarceration of the left lobe of the liver within the right hemithorax, but minimal pulmonary hypoplasia. A search of the literature failed to show a previous report of this variant of a duplication of the diaphragm in conjunction with a congenital diaphragmatic hernia. The approach taken for diaphragmatic reconstruction and closure of the defect is described.

Abnormalities, Multiple↗
PubMed1990

Multiple endocrine neoplasia type II B with symptoms suggesting Hirschsprung's disease: a case report.

A 3-year-old child was referred with a tentative diagnosis of Hirschsprung's disease because of life-long constipation and "megacolon" demonstrated radiographically. Our rectal biopsy revealed hyperganglionosis suggestive of multiple endocrine neoplasia (MEN) type II B. This, in addition to an elevated serum calcitonin level, prompted surgical removal of her thyroid, which appeared grossly normal but on sectioning, contained a medullary carcinoma in each lobe. She remains disease-free 5 years later. Gastrointestinal symptoms are a significant component of the MEN type II B syndrome, and often antedate the full phenotypic expression of the syndrome and the development of potentially lethal endocrine neoplasms. On the basis of this experience, it is recommended that MEN II B be included in the differential diagnosis of chronic constipation.

Child, Preschool↗
PubMed1990

The influence of donor age on graft survival in renal transplantation.

The current supply of kidneys from cadaver and living related donor sources is not sufficient to meet the demand. As a result, alternative sources of renal allografts are being explored, including very young donors and anencephalic newborns. However, data on the success of transplanting kidneys from very young donors are limited and conflicting. The purpose of this study was to determine whether the function and survival of renal grafts obtained from newborns and very young donors is different from that for grafts obtained from older donors. Thirty-six cadaveric donors under the age of 3 years, including seven anencephalic newborns, were evaluated. Allograft recipients ranged in age from 12 months to 57 years. The clinical outcome for these donor organs was compared with the graft survival for 136 kidneys transplanted from cadaver donors over age 3 years at our institution. There was a 65% 6-month and 64% 1-year graft survival in recipients of kidneys from donors greater than or equal to 3 years. Survival of grafts from donors under 12 months of age (n = 16) was significantly decreased compared with donors age 3 years and older, with a 31% 6-month (P less than .01) and 19% 12-month survival (P less than .001). Grafts obtained from anencephalic donors did not differ in survival or function from kidneys obtained from other donors less than 12 months of age. Survival for renal allografts from donors age 13 months to 3 years was also decreased relative to older donors: 55% at 6 months (P greater than .1) and 40% at 1 year (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Acute phase response to endotoxin: rise in plasma alpha-MSH and effects of alpha-MSH injection.

Endotoxins, cell wall components of bacteria, cause a number of biological effects, presumably via induction of potent cytokines. Previous research suggests that the neuropeptide alpha-melanocyte-stimulating hormone (alpha-MSH) and its COOH-terminal tripeptide reduce the effects of cytokines. These molecules evoke antipyretic and anti-inflammatory effects in vivo. Localization of alpha-MSH within lymphocytes and recent observations that alpha-MSH receptors are widespread and that circulating alpha-MSH increases after systemic injection of endogenous pyrogen, a cytokine-containing extract, suggest that the peptide modulates host defense reactions. One aim of the present experiments was to learn whether a rise in circulating alpha-MSH occurs in synchrony with aspects of the acute phase response (APR) in conscious rabbits given endotoxin. A second aim was to learn whether administration of a single large dose of alpha-MSH inhibits all aspects of the APR induced by a low dose of endotoxin. The results indicate that the concentration of circulating alpha-MSH in rabbits does increase along with other changes in the APR (e.g., increase in corticosterone), which suggests that the peptide is widely available to modulate cytokine effects after endotoxin. Contrary to expectations based on previous results, a large dose of the peptide given intravenously inhibited only fever and not other aspects of the APR. The results suggest that the rise in circulating alpha-MSH is an aspect of the APR and that an acute increase in the circulating peptide caused by intravenous injection does not inhibit all other aspects of the host response to endotoxin.

Acute-Phase Reaction↗