The nature of gas production patterns associated with methanol degradation in natural aquifer sediments: A microcosm study

With growing global use of methanol as a fuel additive and extensive use in other industrial processes, there is the potential for unintended release and spills into soils and aquifers. In these subsurface systems it is likely that methanol will be readily biodegraded; however, degradation may lead to the production of by-products, most importantly methane possibly resulting in explosion hazards and volatile fatty acids (VFAs) causing aesthetic issues for groundwater. In this study, the formation of these potentially harmful by-products due to methanol biodegradation was investigated in natural sand and silt sediments using microcosms inoculated with neat methanol (100%) ranging in concentration from 100 to 100,000 ppm. To assess the rate of degradation and by-product formation, water and headspace samples were collected and analyzed for methanol, volatile fatty acids (VFAs, including acetic, butyric, and propionic acid), cation (metal) concentrations (Al, Ca, Fe, K, Mg, Mn and Na), microbial community structure and activity, headspace pressure, gas composition (CH₄, CO₂, O₂ and N₂), and compound specific isotopes. Methanol was completely biodegraded in sand and silt up to concentrations of 1000 ppm and 10,000 ppm, respectively. Degradation was initially aerobic, consuming oxygen (O₂) and producing carbon dioxide (CO₂). When O₂ was depleted, the microcosms became anaerobic and a lag in methanol degradation occurred (ranging from 41 to 87 days). Following this lag, methanol was preferentially degraded to acetate, coupled with CO₂ reduction. Microcosms with high methanol concentrations (10,000 ppm) were driven further down the redox ladder and exhibited fermentation, leading to concurrent acetate and methane (CH₄) generation. In all cases acetate was an intermediate product, further degraded to the final products of CH₄ and CO₂. Carbonates present in the microcosm sediments helped buffer VFA acidification and replenished CO₂. Methane generation in the anaerobic microcosms was short-lived, but temporarily reached high rates up to 13 mg kg^-1 day^-1. Under the conditions of these experiments, methanol degradation occurred rapidly, after initial lag periods, which were a function of methanol concentration and sediment type. Our experiment also showed that methanol degradation and associated methane production can occur in a stepwise fashion.

Long-term monitoring of waste-rock weathering at the Antamina mine, Peru

The weathering of mine waste rock can cause release of metal-laden and acidic drainage that requires long-term and costly environmental management. To identify and quantify the geochemical processes and physical transport mechanisms controlling drainage quality, we monitored the weathering of five large-scale (20,000 t) instrumented waste-rock piles of variable and mixed-composition at the Antamina mine, Peru, in a decade-long monitoring program. Fine-grained, sulfidic waste rock with low-carbonate content exhibited high sulfide oxidation rates (>1 g S kg^-1 waste rock yr^-1) and within 7 years produced acidic (pH < 3) drainage with high Cu and Zn concentrations in the g L^-1 range. In contrast, drainage from coarse, carbonate-rich waste rock remained neutral for >10 years and had significantly lower metal loads. Efficient metal retention (>99%) caused by sorption and secondary mineral formation of e.g., gypsum, Fe-(oxy)hydroxides, and Cu/Zn-hydroxysulfates enforced strong (temporary) controls on drainage quality. Furthermore, reactive waste-rock fractions, as small as 10% of total mass, dominated the overall drainage chemistry from the waste-rock piles through internal mixing. This study demonstrates that a reliable prediction of the timing and quality of waste-rock drainage on practice-relevant spatiotemporal scales requires a quantitative understanding of the prevailing in-situ porewater conditions, secondary mineralogy, and spatial distribution of reactive waste-rock fractions in composite piles.

Cutaneous bacterial colonization, modalities of chemotherapeutic infusion, and catheter-related bloodstream infection in totally implanted venous access devices

GOALS OF WORK

Prospective clinical study to evaluate patients suffering from solid tumor using a totally implanted venous access device (TIVAD) to determine: (1) if there is a relationship between cutaneous contamination at port insertion site and catheter-related bloodstream infection (CRBI); (2) development modalities of CRBI; (3) if there is a relationship between chemotherapy administration modalities by push/ bolus versus continuous infusion and CRBI.

PATIENTS AND METHODS

We studied 41 consecutive patients who needed a TIVAD positioned for chemotherapy administration by bolus/ push or continuous infusion. In every patient, we performed blood cultures from blood samples from port catheters and cutaneous cultures from cutaneous tampons of the skin surrounding the implant area on the first (T0) and eight day (T1) postoperatively, after 1 month (T2), and after 3 months (T3) from insertion.

MAIN RESULTS

The study was completed on 40 patients; in one case, the port was removed at T2 for septic complications. We obtained four positive blood cultures (two, 5%), two in the same patient, all caused by staphylococcus. Positive cutaneous tampons were 21 (13%) in 11 patients (27%); the four CRBI occurred in this group of patients with none in the remaining 30 patients (73%) for a total number of 120 tampons (p<0.01). In two cases, the same germ was isolated from both the skin and blood. None of the patients presented a local infection of the subcutaneous pocket. Positive cutaneous cultures decrease over time: T0-T2; 24-5%; T1-T3, 20-5% (p<0.04). There were no differences in CRBI incidence and positive cutaneous tampons between the two chemotherapy administration modalities.

CONCLUSIONS

Cutaneous microbial flora has a primary role in CRBI development within TIVADs; there is a relationship between cutaneous colonization and CRBI; colonization reaches its maximum during the first days after catheterization in which the use of the system is at high risk; colonization occurs both via extraluminal and endoluminal routes; there is no difference in CRBI incidence between bolus and continuous infusion administration.

Systemic and haemodynamic toxicity after isolated limb perfusion (ILP) with TNF-alpha

The aim of this study was to evaluate the systemic and haemodynamic postoperative effects of ILP with medium-low dose of TNF alpha in patients diagnosed with primary or recurrent limb melanoma or sarcoma, and to compare the resulting toxicity with Systemic Inflammatory Response Syndrome (SIRS). A prospective study on 17 consecutive patients with primary or recurrent limb tumor (melanoma or sarcoma) subjected to ILP with escalating doses of TNF alpha (0.5-2.0mg) was carried out. Seventeen patients with primary or recurrent limb melanoma or sarcoma were subjected to ILP with escalating doses of TNF alpha. ILP was carried out with the standard techniques, blood being warmed at 42 degrees C for an hour. Serial serum TNF alpha determinations were performed before, during and after limb perfusion in nine patients. Systemic and pulmonary haemodynamics, by a radial and pulmonary artery catheter inserted before the induction of anesthesia, were monitored at 5 different times: before the induction of anesthesia (T0), and 6, 12, 24 and 48 hours after treatment (T1-4). Complete isolation of the limb was not always achieved, therefore leakage of TNF alpha occurred frequently during the perfusion in all patients with maximum systemic TNF alpha concentrations ranging from 431 to 111000 pg/ml. After perfusion only two patients showed detectable TNF alpha levels in peripheral blood which returned to baseline values within nine hours. These two patients had serious systemic toxicity: shock and respiratory failure secondary to pulmonary edema. Acute pulmonary edema was also observed in another patient. All three cases required supportive therapy provided by means of mechanical ventilation. In the remaining 14 patients a sepsis-like syndrome was observed. The most significant haemodynamic changes were due to the CO, which rose by 35%, and the SVR, which remained consistently low throughout. A reduction in Hb was observed in all patients (with an average decrease of 4 g/dl), while DO2 and VO2 levels rose, though not to statistically significant levels. Hypoxia occurred in all 14 patients. In three of the remaining 14 cases bilateral pulmonary leaks were noted, however the use of mechanical ventilation was not required. No perioperative death occurred and the aforementioned side effects were all reversible resulting in a patient's mean postoperative ICU permanence of 4 days (range 3 to 7 days). In conclusion, ILP with TNF alpha induces cardiovascular, respiratory and hematological toxicity with haemodynamic parameters being similar to those noted in SIRS probably due to leakage of TNF alpha in the systemic circulation during the perfusion. Nevertheless, this systemic toxicity was short-lived resulting in an acute reaction following a single application.

Hyperthermic antiblastic perfusion with TNFalpha and melphalan in stage III limb melanoma patients: A phase I - II SITILO study

Hyperthermic antiblastic perfusion (HAP) has been proven to be an effective treatment of loco-regional spreading limb melanoma. The mean complete response (CR) rate obtained is 54%, with an objective responses (OR) rate ranging between 70% and 100%. Recently, Tumor Necrosis Factor (TNFalpha) has been employed at high dosages (3-4 mg) in association to Melphalan and hyperthermia. This trimodality combination increased the percentage of CR (70%-90%), but systemic toxicity was also reported due to high TNF doses. A phase I - II study was undertaken in order to assess the MTD of TNFalpha in association to true hyperthermia (41.5 degrees C) and Melphalan. Twenty patients affected with stages IIIA (9 patients), IIIAB (10 patients), and IV (1 patient) were enrolled in this study. The trimodality treatment did not increase the local and systemic toxicity. CR was observed in 70% of the patients, PR in 20% with on OR rate of 90%. These figures are overlapping those obtained with high TNF dosages. No correlation was observed between tumor responses and TNF doses. Taking into account that 70% of our patients have been treated with TNF dosages between 0.5 mg on 1.6 mg, we conclude that 1 mg is the best dosage to be applied during HAP. Patients with bulky tumor are the best candidate to TNF perfusion, because no differences have been observed in terms of CR in patients with low tumor burden treated with TNF-Melphalan-hyperthermia or Melphalan-hyperthermia.

Peritonectomy and hyperthermic antiblastic perfusion in the treatment of peritoneal carcinomatosis

AIMS

Some low-grade malignant tumours arising in the abdomen tend to remain loco-regionally confined to peritoneal surfaces, without systemic dissemination. In these cases complete surgical tumour cytoreduction followed by intra- or post-operative regional chemotherapy has curative potential. The aim of this study was to evaluate the outcome for patients treated in this way.

METHODS

Peritonectomy was performed, involving the complete removal of all the visceral and parietal peritoneum involved by disease. After peritonectomy, hyperthermic antiblastic perfusion was carried out throughout the abdominopelvic cavity for 90 min, at a temperature of 41.5-42.5 degrees C, with mitomycin C (3.3 mg/m2/l) and cisplatin (25 mg/m2/l) (for appendicular or colorectal primaries), or cisplatin alone (for ovarian primaries). Alternatively, the immediate post-operative regional chemotherapy was performed with 5-fluorouracil (13.5 mg/kg) and Lederfolin (125 mg/m2) (for colonic or appendicular tumours) or cisplatin (25 mg/m2) (for ovarian tumours), each day for 5 days.

RESULTS

Thirty-five patients affected by extensive peritoneal carcinomatosis were submitted to peritonectomy, with no residual macroscopic disease in all cases except three. Twenty-six patients were able to undergo the combined treatment involving loco-regional chemotherapy. Complications were observed in 54% of the patients and led to death in four of them. At a mean follow-up of 17 months overall 2-year survival was 55.2%, with a median survival of 26 months.

CONCLUSIONS

After a learning curve of 18 months the feasibility of the integrated treatment increased to more than 90%, while mortality decreased dramatically. The curative potential of the combined therapeutic approach seems high in selected patients with peritoneal carcinomatosis not responding to systemic chemotherapy. Careful selection of patients can minimize the surgical risk, but the treatment should currently be reserved for clinical trials.

Treatment of peritoneal carcinomatosis with intent to cure

BACKGROUND AND OBJECTIVES

Low-grade malignant tumors arise in the abdomen, do not infiltrate, and "redistribute" on the peritoneum with no extraregional spreading. In these cases, aggressive surgery combined with localized chemotherapy may provide cure.

METHODS

After removing the tumor with the regional peritoneum en bloc, intraabdominal hyperthermic chemoperfusion was performed throughout the abdominopelvic cavity. Alternatively, early intraabdominal chemotherapy, starting on the first postoperative day, was administered for 5 days.

RESULTS

Forty patients affected with extensive peritoneal carcinomatosis underwent peritonectomy, with no residual macroscopic disease except in four cases. Seventy-five percent of the patients underwent locoregional chemotherapy. Major complications were observed in 40% of the patients and led to death in five; there was a direct correlation to the duration of surgery (P = 0.03). At a mean follow-up of 20 months, the overall 2-year survival was 61.4%, with a median survival of 30 months.

CONCLUSIONS

After a learning curve of 18 months, the feasibility of the integrated treatment increased to greater than 90%, and mortality dramatically decreased. The combined treatment resulted in a high survival rate in patients with extensive carcinomatosis who were no longer responsive to traditional therapies.

Treatment of peritoneal carcinomatosis with intent to cure

BACKGROUND AND OBJECTIVES

Low-grade malignant tumors arise in the abdomen, do not infiltrate, and "redistribute" on the peritoneum with no extraregional spreading. In these cases, aggressive surgery combined with localized chemotherapy may provide cure.

METHODS

After removing the tumor with the regional peritoneum en bloc, intraabdominal hyperthermic chemoperfusion was performed throughout the abdominopelvic cavity. Alternatively, early intraabdominal chemotherapy, starting on the first postoperative day, was administered for 5 days.

RESULTS

Forty patients affected with extensive peritoneal carcinomatosis underwent peritonectomy, with no residual macroscopic disease except in four cases. Seventy-five percent of the patients underwent locoregional chemotherapy. Major complications were observed in 40% of the patients and led to death in five; there was a direct correlation to the duration of surgery (P = 0.03). At a mean follow-up of 20 months, the overall 2-year survival was 61.4%, with a median survival of 30 months.

CONCLUSIONS

After a learning curve of 18 months, the feasibility of the integrated treatment increased to greater than 90%, and mortality dramatically decreased. The combined treatment resulted in a high survival rate in patients with extensive carcinomatosis who were no longer responsive to traditional therapies.

[Transdermal route as an alternative to oral administration of opioids in cancer pain]

Fentanyl TTS, the only transdermal opioid, represents a real tool for a better quality of life in patients with cancer pain. In this paper we report a short description of the pharmacologic properties and administration procedures of this drug that is a useful alternative when other opioids recommended on the third step of the WHO analgesic ladder, are ineffective or present unbearable side effects (nausea and/or vomiting-severe mucosites and dysphagia). In particular we indicated some changes and adjustments switching from morphine per os to fentanyl TTS. In addition we report the results of a study carried out in our Pain Therapy Center on 49 patients with severe oncologic pain, previously treated with opioids and other drugs associations. Our results indicated a good control of continuous nociceptive cancer pain, with a better quality of life and lesser side effects to respect the previous regime of orally opioids.

Toxic shock syndrome due to group C streptococci. A case report

BACKGROUND

Streptococcal toxic shock-like syndrome is a life-threatening illness which is on the increase. In early reports, only group A beta-hemolytic streptococcus was associated with the disease, but recent evidence indicates non-A streptococci groups are also involved.

OBSERVATIONS

We describe the first reported case of streptococcal toxic shock-like syndrome caused by a group C strain in Italy. Prior to the disease, the patient, a 46-year-old man, had been in good health and had only a 3-day history of sore throat, low grade fever, vomiting, diarrhea, and myalgia before admission. Initially, diagnosis was based only on clinical evidence: shock, multiorgan failure, profound hypothermia, and no apparent signs of infection. Toxic cardiomyopathy was also present.

RESULTS

Positive throat swab and blood culture confirmed a "definite case" following established criteria. Anamnesis showed a diagnosis of monoclonal gammopathy. Antibiotic treatment was begun immediately on admission of the patient, who was discharged 20 days later in good health.

CONCLUSIONS

This case illustrates how an early diagnosis and prompt antibiotic therapy can determine a more favorable outcome.

Complications with fully implantable venous access systems in oncologic patients

AIMS

To evaluate the complications caused by long-term central venous catheterization in patients with malignant hemopathies or solid tumors.

METHODS

Retrospective study from June 1988 to June 1993 in 211 consecutive patients who required 223 venous access devices for long-term use. A consistent analysis was possible only in 161 of these patients.

RESULTS

Fourteen catheter systems were removed for complications. Infections were the most common complications, with an overall incidence rate of 9.6%, i.e. 0.033/100 catheter days/patient. A significant difference was noted between the two groups of patients: 10 cases (24%) in malignant hemopathies, 6 cases (4.8%) in solid tumors (P = 0.0002). The main mechanical complication was thrombosis, with an incidence rate of 3%.

CONCLUSIONS

Given the cost-benefit ratio, our study indicates that fully implantable venous access systems in oncologic patients are extremely useful.

[Thrombocytopenia and thrombophilic state in heparin therapy]

The authors report two clinical cases of thrombocytopenia and thrombosis which occurred during profilaxys and therapy with heparin. The mechanisms involved are reviewed and the possible therapeutic role of heparin-like drugs is discussed according to data presented in the international literature.

[Tetraplegia and acute respiratory insufficiency from an ischemic cervical medulla lesion after cocaine use. A clinical case]

The article deals with a case report on tetraplegia and acute respiratory failure following ischemic damage of the spinal medulla in the cervical tract due to cocaine assumption. The ischemic damaged produced by cocaine usually injure the great vessels of the cranial base. The case report is particular because of the area and the seize of the injured vessel. Finally, the most important hypotheses about the pathogenesis in the ischemic cerebrovascular cocaine-induced damages are debated.

[Echo-guided percutaneous celiac plexus block with alcohol with an anterior approach]

The authors report the use of ultrasound as a guide to the execution of celiac plexus alcoholization with the anterior approach. Five patients with severe pain resistant to pharmacologic treatment with NSAID, cortisone and morphine have been treated. Once found out the celiac trunk and the best direction, using ultrasound, the needle is advanced slowly beyond the anterior lateral wall of the aorta, in order to recognize the tip with the same ultrasound response of the retroperitoneal tissue. After calculating the distance between the celiac trunk and the needle tip, this is withdrawn in order to be set in the alcoholization point of injection. No complication directly related to the technique has been observed in the five patients. Pain relief was optimal in four out of five patients and was kept until the exitus.