Evaluation of Clinical Prognostic Factors and Further Delineation of the Effect of Mesenteric Fibrosis on Survival in Advanced Midgut Neuroendocrine Tumours

BACKGROUND

Small intestinal neuroendocrine tumours (SI NETs) represent 30-50% of small bowel neoplasms and often present at an advanced stage. To date, there is relatively limited literature regarding prognostic factors affecting overall survival (OS) in stage IV disease. In addition, the prevalence of mesenteric fibrosis (MF) in SI NETs and its effect on OS have not been sufficiently explored in the literature.

AIM

The primary aim of this study was to perform a large-scale survival analysis in an institutional cohort of 387 patients with metastatic (stage IV) SI NETs. The secondary aim was to provide epidemiological information regarding the prevalence of MF and to evaluate its effect on OS.

RESULTS

The median OS was 101 months (95% CI 84, 118). Age > 65 years, mesenteric metastases with and without desmoplasia, liver metastases, carcinoid heart disease (CHD) and bone metastases were associated with a significantly shorter OS, while primary tumour resection was predictive of a longer OS. The benefit of surgical resection was limited to symptomatic patients. MF was present in approximately 50% of patients with mesenteric lymphadenopathy. Elevated urinary 5-HIAA levels correlated strongly with the presence of CHD (p < 0.001) and to a lesser extent (p = 0.02) with MF. MF and CHD did not usually co-exist, suggesting that different mechanisms are likely to be involved in the development of these fibrotic complications.

CONCLUSIONS

This study has identified specific prognostic factors in a large cohort of 387 patients with advanced SI NETs and has provided useful epidemiological data regarding carcinoid-related fibrotic complications.

Assessment of growth hormone dynamics in human immunodeficiency virus-related lipodystrophy

Human immunodeficiency virus (HIV) lipodystrophy (LIPO) is characterized by increased visceral adiposity, peripheral fat atrophy, dyslipidemia, and insulin resistance. GH concentrations are known to vary inversely with excess weight and body fat but have not been investigated in HIV lipodystrophy. Twenty-one subjects with HIV LIPO, 20 HIV-infected nonlipodystrophy subjects (NONLIPO), and 20 control (C) subjects were prospectively recruited for this study and compared. Subjects in the three groups were all male, age-matched [median, 47 yr old (interquartile range, 37-50) LIPO; 41 (37-44) NONLIPO; and 43 (37-49) C], and body mass index-matched [median, 24.3 kg/m(2) (interquartile range, 22.2-26.6) LIPO; 24.4 (23.3-25.9) NONLIPO; and 24.8 (22.7-26.1) C] (P: > 0.05 for all comparisons). Visceral abdominal fat [16,124 mm(2) (11,246-19,790) LIPO; 7,559 (5,134-11,201) NONLIPO; and 8,803 (6,165-11,623) C; P < 0.01 LIPO vs. NONLIPO and LIPO vs. C] and the ratio of visceral abdominal fat to sc abdominal fat [1.37 (0.71-2.44) LIPO vs. 0.57 (0.47-0.78) NONLIPO vs. 0.55 (0.41-0.71) C, P < 0.01 LIPO vs. NONLIPO and LIPO vs. C] were significantly increased in the LIPO subjects but were not significantly different between NONLIPO and C. The mean overnight GH concentration, determined from frequent sampling every 20 min (from 2000 h to 0800 h) was decreased in the LIPO subjects [0.38 microg/L (0.13-0.67) LIPO vs. 0.96 (0.53-1.30) NONLIPO vs. 0.81 (0.49-1.03) C, P < 0.05 LIPO vs. NONLIPO and LIPO vs. C] and not significantly different between NONLIPO and C. Pulse analysis demonstrated decreased baseline GH [0.08 microg/L (0.06-0.21) LIPO vs. 0.19 (0.10-0.32) NONLIPO vs. 0.17 (0.12-0.57) C, P < 0.05 LIPO vs. NONLIPO and LIPO vs. C] and GH peak amplitude [1.06 microg/L (0.46-1.94) LIPO vs. 2.47 (1.22-3.43) NONLIPO and 2.27 (1.36-4.25) C, P < 0.05 LIPO vs. NONLIPO and LIPO vs. C] in the LIPO subjects but no significant difference in pulse frequency. No significant differences were observed between NONLIPO and C for any GH parameter. Insulin-like growth factor-I was not different between the groups. Total body fat (r = -0.40, P = 0.01) and visceral fat (r = -0.58, P = 0.0001) correlated inversely with mean overnight GH concentrations in the HIV-infected patients. In a multivariate regression model, controlling for age, body mass index, body fat, and visceral fat, only visceral fat was a significant predictor of mean GH concentrations (P = 0.0036, r(2) for model = 0.40). These data demonstrate normal GH pulse frequency and insulin-like growth factor-I concentrations but reduced mean GH concentrations, basal GH concentrations, and GH pulse amplitude in patients with HIV lipodystrophy. Increased visceral adiposity is the strongest predictor of reduced GH concentrations in HIV lipodystrophy. Further studies are necessary to determine the clinical significance of reduced GH in patients with HIV lipodystrophy.

[Infectious sequellae of 913 central catheters in oncology]

Infections associated with central catheters are a significant source of morbidity in cancer patients. The first evaluation done as part of a continuous catheter surveillance program included the 913 central catheters inserted in 1995. Three of these catheters are still in place. All were tunneled subcutaneously, and most were inserted via the subclavian route. There were 839 simple silicone catheters and 74 catheters with a cuff. Two groups were defined based on whether the central catheter was inserted for administering inpatient or outpatient chemotherapy (n = 704) or for another reason (perioperative care, symptomatic or palliative therapy; n = 209). Catheter-related infection was defined as an infection at the catheter site or as septicemia retrospectively shown to be related to the catheter. The risk of catheter-related infection was expressed as the number of cases per 1000 days of catheterization. Reasons for catheter removal were distributed in table I.

Partial growth-hormone insensitivity: the role of growth-hormone receptor mutations in idiopathic short stature

Mutations in the GHR locus may play a role in the cause of idiopathic short stature (ISS) by impairing growth-hormone (GH) receptor (GHR) function. At one extreme, mutations that nullify the function of the GH receptor are linked to complete GH insensitivity syndrome, or Laron syndrome, and we hypothesized that less-disruptive mutations could contribute to partial GH insensitivity syndrome. Low levels of GH binding protein may indicate mutations in the extracellular domain of the receptor, and by focusing on 14 children with ISS who had low GH binding protein and insulin-like growth factor I levels, we found three heterozygotes and one compound heterozygote for mutations in the extracellular domain of the receptor. We have since extended our study to a broader spectrum of patients, adding 76 patients with ISS who were treated with GH in a phase II study of the safety and efficacy of recombinant human GH in ISS and also adding 10 patients who were ascertained as having ISS by pediatric endocrinologists in private practice. The GHR gene has thus been analyzed in 100 patients with ISS, eight of whom were found to carry mutations: four in our original study and four with normal or elevated levels of GH binding protein. The latter group consists of three carriers of heterozygous extracellular domain mutations and one carrier of a heterozygous intracellular domain mutation. Family data suggest that the carriers of these mutations have a range of phenotypes, supporting our hypothesis that the expression of these heterozygous mutations as partial GH insensitivity syndrome depends on the genetic makeup of the person.

Resistance to ceftriaxone and other beta-lactams in bacteria isolated in the community. The Vigil'Roc Study Group

The incidence of bacterial species and their susceptibilities to ceftriaxone and other beta-lactams from patients with community-acquired infections were evaluated in a multicenter study over a 4-month period. A total of 5,768 bacterial isolates were classified according to whether the patient had been previously hospitalized or had received antibiotic treatment. The most relevant findings were the presence of 33.8% penicillin-resistant Streptococcus pneumoniae isolates, 25% beta-lactamase-producing Haemophilus influenzae isolates, and 36.4% amoxicillin-resistant Escherichia coli isolates. All of these bacteria were fully susceptible to ceftriaxone. Nosocomial multiply-resistant bacteria, and particularly methicillin-resistant S. aureus, were found, as expected, at a higher frequency among previously hospitalized patients. However, such bacteria may be present in the community; their incidence is high in particular clinical settings, and such bacteria should be considered when one is choosing a first-line therapy for the treatment of severe infections.

Use of cefotaxime or ceftazidime susceptibility tests for predicting susceptibility of Enterobacteriaceae and Pseudomonas aeruginosa

To determine if susceptibility to aztreonam could be predicted from cefotaxime or ceftazidime disc diffusion testing, 919 Enterobacteriaceae and 187 Pseudomonas aeruginosa clinical strains were studied. The correlation coefficient between the diameters of inhibition zones was 0.9 for cefotaxime versus aztreonam and ceftazidime versus aztreonam comparisons in Enterobacteriaceae and 0.75 for ceftazidime versus aztreonam comparison in P. aeruginosa. For 99% of the Enterobacteriaceae, there was no risk in predicting susceptibility to aztreonam on the basis of cefotaxime or ceftazidime susceptibility tests. To minimize the risk of the remaining 1% of the strains being erroneously classified as susceptible to aztreonam, ceftoaxime should be tested in preference to ceftazidime, and the production of extended-spectrum beta-lactamases should be tested for using the cefotaxime-clavulanate disc synergy test. For P. aeruginosa strains, susceptibility to aztreonam could be accurately predicted from ceftazidime susceptibility tests for ticarcillin susceptible strains, but for ticarcillin resistant strains, susceptibility to aztreonam should be tested.

Characterization of ceftriaxone-resistant Enterobacteriaceae: a multicentre study in 26 French hospitals. Vigil'Roc Study Group

During a multicentre study performed in 26 French hospitals, 287 (3.2%) of 9038 Enterobacteriaceae isolated, mainly Enterobacter spp., Serratia spp., Citrobacter spp. and Klebsiella spp. were classified as ceftriaxone resistant on the basis of an MIC > 4 mg/L or the presence of an extended-spectrum beta-lactamase. Extended-spectrum beta-lactamase was present mainly in Klebsiella pneumoniae (65 strains, 10.2%) and very rarely in Escherichia coli, Proteus mirabilis, Klebsiella oxytoca, Citrobacter spp. and Enterobacter spp. The extended-spectrum beta-lactamases conferred low-level resistance to ceftriaxone in nearly 60% of the strains harbouring them, emphasizing the need for routine testing for the presence of these enzymes. Among transconjugants three types of extended-spectrum beta-lactamase were identified. Those resembling TEM-3 were the most common, but TEM-21, and SHV-4 were also found. Clavulanate and to a lesser extent sulbactam inhibited all the extended-spectrum beta-lactamases encountered in this study.

Noninvasive pressure support ventilation in patients with acute respiratory failure

To further delineate indications for noninvasive pressure support ventilation (NIPSV), we proposed this noninvasive technique as an alternative to endotracheal intubation in 17 consecutive patients with acute respiratory failure from various causes. Eight patients (47 percent) were successfully ventilated with NIPSV, while in 9 (53 percent), NIPSV failed. Gas exchange values before initiating NIPSV were different between the 2 groups: patients successfully ventilated with NIPSV had a higher PaCO2 (57 +/- 15 mm Hg vs 37 +/- 17 mm Hg; p = 0.01), a lower pH (7.33 +/- 0.03 vs 7.45 +/- 0.08; p = 0.02), and a lower alveolo-arterial oxygen pressure difference (P[A-a]O2) (144 +/- 46 mm Hg vs 265 +/- 18 mm Hg; p = 0.01), suggesting that CO2 retention without major hypoxemia is a better indication for NIPSV than severe hypoxemia alone. Acute respiratory failure occurring after extubation seemed to be a good indication for NIPSV, with an 83 percent rate of success. In both groups of patients, gas exchange improved after 1 h on NIPSV, but such values were not improved on the first day in patients who failed with NIPSV.

[Enterobacteriaceae isolated in nine general hospitals of the Ile-de-France in 1988 and 1989: susceptibility to beta-lactam antibiotics according to the length of hospitalisation]

Susceptibility to beta-lactam antibiotics of strains of Enterobacteriaceae consecutively isolated in nine general hospitals during a period of 2 months (march and april) has been studied by the disk-agar diffusion method. The separation between susceptible and resistant strains was based on the measure of the inhibition zones centered by 2 disks: cephalothin and ticarcillin. Enterobacteriaceae were divided in 2 groups: strains isolated during the first 48 h of hospitalisation or isolated after. Fifty one per cent of the strains were isolated during the first 48 h: they did not belong to the residential flora of these hospitals. Klebsiella, Proteus indole positive, Providencia, Enterobacter, Serratia were more frequently isolated after 48 h of hospitalisation. Susceptible strains of Klebsiella, Proteus indole positive, Providencia, Serratia were more rarely isolated after 48 h of hospitalisation. E. coli whatever the duration of hospitalisation, is the less frequent susceptible bacterium.

Influence of substrate background on peripheral tissue responses to growth hormone

To evaluate the effects of substrate and hormonal background on the peripheral response to methionyl human growth hormone (met-hGH), metabolic measurements were performed in 10 normal subjects before and at the end of a 6-hr infusion of met-hGH. Five subjects were studied in the postabsorptive state and five were studied on the 10th day of intravenous repletion. Measurements of hormonal levels, serum amino acid levels, and free fatty acid levels, as well as extremity amino acid and free fatty acid fluxes, were performed. Met-hGH in the postabsorptive setting had no effect on extremity amino acid flux but significantly increased extremity free fatty acid efflux. In contrast, met-hGH in the background of intravenous feeding produced a significant extremity uptake of total amino acids but had no effect on free fatty acid flux. These data suggest a relationship between the substrate background and the actions of met-hGH on both peripheral protein and lipid metabolism. Therefore, the adequacy and composition of the feeding regimen may be important when considering growth hormone as an adjunct to nutritional therapy.

Deranged alpha-adrenergic regulation of growth hormone secretion in poorly controlled diabetes: reversal of the exaggerated response to clonidine after continuous subcutaneous insulin infusion

Elevated plasma growth hormone (GH) and peripheral catecholamine levels are frequently observed in poorly controlled, insulin-dependent diabetes. Since the alpha adrenergic system plays an important role in hypothalamic regulation of GH secretion, we tested the hypothesis that altered central adrenergic activity contributes to the increased GH concentrations in diabetes. Clonidine, an alpha-adrenergic agonist, was administered to nine poorly controlled, young diabetic patients (age 12-19 yr) before and after 1 wk of continuous subcutaneous insulin infusion pump therapy. As expected, continuous subcutaneous insulin infusion lowered mean 24-h plasma glucose (from 203 +/- 21 to 112 +/- 7 mg/dl, p less than 0.01) and GH (from 17.7 +/- 2.1 to 9.2 +/- 1.2 ng/ml, p less than 0.01) to values observed in normal controls. In the diabetic patients during conventional treatment, both the peak plasma GH level postclonidine (48.3 +/- 8.7 ng/ml) and the incremental area under the GH response curve (3.23 +/- 0.58 mg X min/ml) were significantly increased above normal control values (25.2 +/- 2.1 ng/ml, p less than 0.05 and 1.63 +/- 0.11 mg X min/ml, p less than 0.0025, respectively). In contrast, the GH response to clonidine was indistinguishable from normal after only 1 wk of intensified insulin treatment. Our findings support the contention that metabolic control of diabetes influences hypothalamic regulation of GH secretion and suggests that such alterations are related, at least in part, to changes in central alpha-adrenergic activity.

Improved diabetic control enhances erythroid stem cell proliferation in vitro

Patients with type I diabetes mellitus treated with continuous sc insulin infusion (CSII) have improved glucose homeostasis, metabolic control, and linear growth. To determine the influence of CSII on cellular growth in vitro, we used a clonal stem cell assay for proliferation of erythroid progenitors, [burstforming units-erythroid (BFU-E)] in peripheral blood. Eight patients were studied before and after 1 week of CSII. Improvement in metabolic control was demonstrated by a decrease in mean 24-h plasma glucose from 232 +/- 29 (+/- SEM) mg/dl before treatment to 112 +/- 3 mg/dl after treatment (P = 0.01). Somatomedin-C levels increased from 1.1 +/- 0.4 to 1.4 +/- 0.4 U/ml (P less than 0.001). Numbers of BFU-E-derived colonies were not different from normal during conventional treatment, but increased 300% after 1 week of CSII. Our findings indicate that the acute metabolic and hormonal improvements that accompany short term CSII therapy in vivo are associated with a striking increase in the proliferation of erythroid committed stem cells in vitro.

Long-term treatment of familial hypophosphatemic rickets with oral phosphate and 1 alpha-hydroxyvitamin D3

Combined treatment with oral phosphate and 1 alpha (OH)D3 was carried out in nine children with familial hypophosphatemic rickets. All nine had positive responses over a four- to six-year period as judged by healing of rickets, change in growth rate, decrease in alkaline phosphatase activity, and symptomatic improvement. In two patients therapy was stopped for a short time because of hypercalcemia. In one patient in whom therapy was effective there was a significant reduction in creatinine clearance which necessitated cessation of treatment. The results of this study suggest that combined treatment with 1 alpha(OH)D3 and oral phosphate is an effective form of therapy for this condition, but that the balancing of these two modalities of therapy in each patient is essential if hypercalcemia and hypercalciuria, on the one hand, and secondary hyperparathyroidism, on the other, are to be avoided. A simple means of balancing these therapeutic modalities is suggested.

Risk of infection in prolonged central venous catheterization

Classically, duration of infusion was thought to increase the rate of contamination by catheters. The results of this study show that this is not true and that, to the contrary, there is a definite difference in contamination rates between the basilic and the jugular and subclavian veins. The advantage of the basilic way which exists whatever the pathologic condition must undoubtedly determine the choice of this way of catheterization rather than any other.