Current trends in infection imaging

Infection imaging is a field of intense interest in medicine because, despite the great advances in our understanding of microorganisms and the development of new antimicrobial agents, infection remains a major cause of patient morbidity and mortality. Nuclear Medicine for many years has an important role in this field. The significance of this role varies in different clinical situations, in some cases being complementary to other imaging modalities as in postoperative patients, and in some cases being the method of choice as in orthopaedic infections after implants have been placed. Today there are many agents in Nuclear Medicine capable in imaging infection. Each of them has its own advantages and drawbacks. In recent years there is an increased research in the field with new methods tested. Among them are labelled antibacterial agents, labelled antimicrobial peptides, monoclonal antibodies for leukocyte labelling, labelled liposomes, and (18)F-FDG-PET. In this short article there is an effort to briefly review these agents and their possible role in infection imaging.     

Costing nuclear medicine diagnostic procedures

To the Editor: Referring to a recent special report about the cost analysis of twenty-nine nuclear medicine procedures, I would like to clarify some basic aspects for determining costs of nuclear medicine procedure with various costing methodologies. Activity Based Costing (ABC) method, is a new approach in imaging services costing that can provide the most accurate cost data, but is difficult to perform in nuclear medicine diagnostic procedures. That is because ABC requires determining and analyzing all direct and indirect costs of each procedure, according all its activities. Traditional costing methods, like those for estimating incomes and expenses per procedure or fixed and variable costs per procedure, which are widely used in break-even point analysis and the method of ratio-of-costs-to-charges per procedure may be easily performed in nuclear medicine departments, to evaluate the variability and differences between costs and reimbursement - charges.     

Late Perforation of the Jejuno-Jejunal Anastomosis after Laparoscopic Roux-en-Y Gastric Bypass

Roux-en-Y gastric bypass (RYGBP) is the most commonly performed operation for the treatment of morbid obesity in the USA. Complications related to the jejuno-jejunal (J-J) anastomosis include postoperative leak, staple-line bleeding and obstruction. We present 3 cases of perforation at the J-J anastomosis occurring more than 30 days after surgery. 3 morbidly obese patients underwent laparoscopic RYGBP. The side-to-side J-J anastomosis was created with a linear stapler, and the anastomotic defect was closed with a running absorbable suture. All 3 patients had uneventful recoveries, but presented 7 to 8 weeks postoperatively with acute abdominal pain and peritoneal signs. Exploratory laparoscopy in these patients revealed a perforation at the J-J anastomosis. No apparent reason for the perforation was found in 2 patients. These perforations were repaired laparoscopically with absorbable suture. The third patient had an obstruction at the J-J anastomosis from an phytobezoar and required conversion to open technique due to limited pneumoperitoneum. All 3 patients recovered uneventfully. Late perforation of the J-J anastomosis is a very rare complication. Primary laparoscopic repair is a feasible and safe choice of treatment.     

Respiratory failure: an overview

Respiratory failure is defined as a failure in gas exchange due to an impaired respiratory system--either pump or lung failure, or both. The hallmark of respiratory failure is impairment in arterial blood gases. This review describes the mechanisms leading to respiratory failure, the indices that can be used to better describe gas exchange abnormalities and the physiologic and clinical consequences of these abnormalities. The possible causes of respiratory failure are then briefly mentioned and a quick reference to the clinical evaluation of such patients is made. Finally treatment options are briefly outlined for both acute and chronic respiratory failure.     

Superior Mesenteric Artery Syndrome after Laparoscopic Roux-en-Y Gastric Bypass for Morbid Obesity

Gastrointestinal obstructive complications after laparoscopic Roux-en-Y gastric bypass (LRYGBP) are not uncommon. Their usual causes are strictures, internal hernias and adhesions. Superior mesenteric artery (SMA) syndrome is a rare disorder caused by compression of the third portion of the duodenum by the SMA that can occur after rapid weight loss. This has been reported in patients with scoliosis, burns, immobilization in body casts, and idiopathic weight loss. SMA syndrome following bariatric surgery has not been reported. We present 3 cases of SMA syndrome after LRYGBP and extensive weight loss. Two patients underwent laparoscopic duodenojejunostomy and the third patient was treated with intravenous hyperalimentation. All three are symptom free at 4-18 months follow-up. The diagnosis of SMA syndrome should be considered in bariatric surgery patients with rapid weight loss who develop atypical, recurrent obstructive symptoms not attributable to other common causes.     

Melanin-concentrating hormone receptor mutations and human obesity: functional analysis

Melanin-concentrating hormone (MCH), a neuropeptide highly expressed in the lateral hypothalamus, has an important role in the regulation of energy balance and body weight in rodents. We examined whether mutations in the two known MCH receptors might be associated with obesity-related phenotypes in humans. Among 106 subjects with severe early onset obesity and a history of hyperphagia, we found two missense variants in MCHR1: Y181H and R248Q. Neither of these was found in 192 normal weight controls. R248Q cosegregated with obesity across two generations; family data were unavailable for Y181H. When expressed in HEK293 cells, R248Q showed no evidence of constitutive activation or ligand hypersensitivity for extracellular signal-regulated kinase phosphorylation. In addition, R248Q showed no enhanced suppression of cAMP generation. Two common single-nucleotide polymorphisms were found to be in linkage disequilibrium: g.-114A>G and c.39C>T. No association between either of these single-nucleotide polymorphisms and obesity-related phenotypes was found among a population cohort of 541 whites. Only two rare noncoding variants were found in MCHR2. In conclusion, mutations in the MCH receptors are not commonly found in humans with severe early onset obesity. Clarification of the relationship of these variants to obesity must await study in other populations and/or in genetically modified mice.     

Increased serum CA-15.3 levels in patients with megaloblastic anemia due to vitamin B12 deficiency

OBJECTIVES: To estimate the usefulness of serum tumor markers' monitoring, as predictors of gastric cancer in patients with pernicious anemia. PATIENTS AND METHODS: We investigated serum levels of carcinoembryonic antigen (CEA), alpha-fetal protein, cancer antigen (CA)-19.9, CA-125 and CA-15.3 in 50 patients with pernicious anemia and in 24 healthy controls, matched for age and sex. In 38 patients, the evaluation was repeated 1-6 months after the correction of cobalamin deficiency. RESULTS: All patients and controls had normal serum CEA and alpha-FP, and the levels of these markers as well as those of CA-125 and CA-19.9 did not differ between the two groups. All 50 patients, but only 2 controls exhibited increased serum CA-15.3, and the difference between the two groups was very significant (129.4 +/- 84.9 vs. 19.8 +/- 7.3 IU/ml, p < 0.001), while no difference between males and females was found. A thorough clinical examination of all patients, and mammographic study in 18 females did not reveal any finding suspicious of breast cancer. CA-15.3 levels were positively correlated with serum lactate dehydrogenase, and negatively with B(12) and hemoglobin, but they were substantially decreased after the correction of anemia, in all 38 patients tested, and in 33 of them they were restored to normal. After a median follow-up of 34 months, one patient developed a colon cancer, but none showed any sign suspicious of breast cancer. CONCLUSIONS: Serum CA-15.3 shows an aberrant increase in untreated patients with pernicious anemia, which is reversed after the correction of the anemia. The possible origin seems unrelated to mammary tissue, and may be released by the apoptosing bone marrow megaloblastic erythroblasts.     

Pegylated liposomal doxorubicin hydrochloride (PLD) and paclitaxel in recurrent or metastatic head and neck carcinoma: a phase I/II study conducted by the Hellenic Cooperative Oncology Group (HeCOG)

A phase I pharmacokinetics and dose-finding study and a phase II study of the combination of pegylated liposomal doxorubicin HCl (PLD) and paclitaxel were conducted in patients with recurrent or metastatic head and neck cancer (HNC). Sixty patients with recurrent or metastatic disease were enrolled in the study: 11 patients in the phase I study and 49 patients in the phase II study. In the phase I study, the initial dose level of PLD was 35 mg/m as a 1-h infusion with escalating increments of 5 mg/m until the maximum tolerated dose (MTD) was reached. A fixed dose of paclitaxel (175 mg/m) was administered as a 3-h infusion. The combination was administered every 28 days. Pharmacokinetic studies performed on 10 patients indicated that the sequence of drug administration did not cause clinically significant modifications in the pharmacokinetics of either drug. The MTD for PLD was 45 mg/m (dose level 3) and the dose-limiting toxicity was febrile neutropenia, occurring in three of five patients. The phase II dose of PLD was 40 mg/m (dose level 2) and a total of 214 cycles were delivered. Grade 3 or 4 neutropenia was observed in 26% patients and febrile neutropenia occurred in 16% of patients. Grade 3 palmar-plantar erythrodysesthesia (PPE) was recorded in only one patient. The overall response rate was 28% for patients with non-nasopharyngeal tumors [95% confidence interval (CI) 15-45%] and 28.6% for the study population (95% CI 17-43%). The median survival for the study population was 9.7 months; 1-year survival was 38%. We conclude that the recommended dose for the combination of PLD and paclitaxel is 40 and 175 mg/m every 28 days, without granulocyte colony stimulating factor support. The combination of paclitaxel with PLD demonstrated activity in recurrent or metastatic HNC, a favorable toxicity profile and relative ease of administration.