[Splenic abscess]

Splenic abscess is a rare and potentially lethal clinical condition. The most common symptoms of a splenic abscess - abdominal pain, nausea and fever - are non-specific. As a result, a splenic abscess is often not considered in the initial work-up. This might lead to a delay in diagnosis and treatment. In this case series we successively describe a 41-year-old female with a splenic abscess after Streptococcus milleri bacteraemia, a 78-year-old male with a splenic abscess caused by a colon carcinoma and a 52-year-old male with a splenic abscess resulting from a colosplenic fistula after bariatric surgery. By emphasizing the different aetiologies, the different clinical presentations and the different therapeutic options of a splenic abscess, we aim to create greater awareness of this rare clinical phenomenon.

[Thrombocytopenia]

Thrombocytopenia can be caused by many different underlying disorders. The diagnostic approach to this haematological abnormality may, therefore, be challenging for physicians. Causes of thrombocytopenia may be classified according to decreased production, increased peripheral consumption or destruction, or abnormal distribution of platelets. Additionally, it is important to rule out pseudothrombocytopenia, a laboratory artefact caused in vitro by ethylenediaminetetraacetic acid (EDTA) anticoagulants. Here we discuss the clinical and laboratory evaluation of drug-induced thrombocytopenia based on the description of two patients, one with ceftriaxone-induced thrombocytopenia and the other with heparin-induced thrombocytopenia. Drug-induced thrombocytopenia is rare, but it is an important consideration in the differential diagnosis of thrombocytopenic patients. The aetiology is often not recognised or is ascribed to other complications such as disseminated intravascular coagulation (DIC) or immune thrombocytopenia (ITP). Misdiagnosis or late recognition may result in morbidity and mortality due to bleeding or thrombotic complications.

Evolution of animal models in cancer vaccine development

Advances in cancer vaccine development are facilitated by animal models reflecting key features of human cancer and its interface with host immunity. Several series of transplantable preneoplastic and neoplastic mouse mammary lesions have been used to delineate mechanisms of anti-tumor immunity. Mimicking immune tolerance to tumor-associated antigens (TAA) such as HER2/neu, transgenic mice developing spontaneous mammary tumors are strong model systems for pre-clinical vaccine testing. In these models, HER2 DNA vaccines are easily administered, well-tolerated, and induce both humoral and cellular immunity. Although engineered mouse strains have advanced cancer immunotherapy, basic shortcomings remain. For example, multiple mouse strains have to be tested to recapitulate genetic regulation of immune tolerance in humans. Outbred domestic felines more closely parallel humans in the natural development of HER2 positive breast cancer and their varying genetic background. Electrovaccination with heterologous HER2 DNA induces robust adaptive immune responses in cats. Importantly, homologous feline HER2 DNA with a single amino acid substitution elicits unique antibodies to feline mammary tumor cells, unlocking a new vaccine principle. As an alternative approach to targeted vaccination, non-surgical tumor ablation such as cryoablation induces anti-tumor immunity via in situ immunization, particularly when combined with toll-like receptor (TLR) agonist. As strategies for vaccination advance, non-invasive monitoring of host response becomes imperative. As an example, magnetic resonance imaging (MRI) and positron emission tomography (PET) scanning following administration of tryptophan metabolism tracer [11C]-alpha-methyl-tryptophan (AMT) provides non-invasive imaging of both tumor growth and metabolic activities. Because AMT is a substrate of indoleamine-pyrrole 2,3-dioxygenase (IDO), an enzyme that produces the immune regulatory molecule kynurenine, AMT imaging can provide novel insight of host response. In conclusion, new feline models improve the predictive power of cancer immunotherapy and real-time PET imaging enables mechanistic monitoring of host immunity. Strategic utilization of these new tools will expedite cancer vaccine development.

Immunotherapeutic intervention with oncolytic adenovirus in mouse mammary tumors

The goal is to elucidate the immune modulating activity of an adenovirus (Adv) vector which showed therapeutic activity in human clinical trials. The oncolytic adenovirus (Adv/CD-TK) expressing two suicide genes was tested in two HER2/neu positive BALB/c mouse mammary tumor systems: rat neu-induced TUBO and human HER2-transfected D2F2/E2. Intra-tumoral (i.t.) Adv/CD-TK injection of TUBO tumor plus systemic prodrug therapy showed limited antitumor activity, not exceeding that by the virus itself. Antibody (Ab) to the virus was induced in Adv-/Luc-treated mice, to coincide with the loss of transgene expression. Low replication activity of adenoviruses in rodent cells may limit viral persistence. Host immunity against Adv or Adv-infected cells further mutes suicide gene activity. Treatment of TUBO tumors with Adv/CD-TK alone, however, induced neu-specific Ab responses. Treatment with Adv/CD-TK/GM (Adv/GM) that also expressed mouse granulocyte macrophage colony stimulating factor (GM-CSF), but without prodrug treatment, delayed tumor growth, enhanced anti-neu Ab production and conferred complete protection against secondary tumor challenge. D2F2/E2 tumor-bearing mice showed decreased tumor growth following i.t. Adv/GM treatment and they generated greater HER2-specific T-cell responses. These data suggest that i.t. injection of Adv itself induces immune reactivity to tumor-associated antigens and the encoded cytokine, GM-CSF, amplifies that immune response, resulting in tumor growth inhibition. Incorporation of suicide gene therapy did not improve the efficacy of Adv therapy in this mouse mammary tumor system. Oncolytic adenoviral therapy may be streamlined and improved by substituting the suicide genes with immune modulating genes to exploit tumor immunity for therapeutic benefit.

Abstract 2693: Amplification of tumor immunity with cryoablation

Tumor cryoablation, the use of freezing temperatures to destroy tumor tissue while preserving tumor-associated antigens, has the potential to initiate or amplify tumor immunity. However, enhanced tumor immunity is not consistently observed in treated patients, suggesting inadequate immune priming by cryoablation itself. We hypothesize that cryoablation in coordination with DNA vaccination and/or immune modulation will amplify effector mechanisms to provide long-term anti-tumor protection. BALB/c mice implanted with a neu expressing mammary tumor TUBO received two electro-vaccinations 10 days apart, with neu DNA or blank vector, followed 4 days later with cryoablation or sham surgery of the tumor. Mice receiving both neu vaccination and cryoablation produced a 3-fold higher anti-neu antibody titer over neu vaccination alone (P<0.02) and a 16-fold higher titer over cryoablation alone (P<0.003). Combination treatment also provided full protection against TUBO re-challenge, supporting enhanced immunity by cryoablation. To test the effect of combining cryoablation with the depletion of regulatory T cells (Treg), 12 week old BALB Neu transgenic mice which had spontaneously developed ductal carcinoma in situ in the mammary glands were treated with α-CD25 mAb to deplete Tregs, partial cryoablation of the 4th mammary gland, or a combination of both. Development of palpable mammary tumor throughout all ten mammary glands was significantly delayed in mice receiving combination treatment over either treatment alone, indicating amplification of tumor immunity in Treg depleted mice by cryoablation. The mechanisms of amplified immunity are being investigated by analyzing a panel of inflammatory cytokines in the serum as well as gene expression in lymphocytes in the tumor, spleen, and tumor draining lymph nodes at different points after cryoablation. Phenotyping of tumor infiltrating immune cells post-cryoablation is also being assessed.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2693. doi:10.1158/1538-7445.AM2011-2693

Clostridium perfringens septicaemia with massive intravascular haemolysis: a case report and review of the literature

We describe the case of a 74-year-old man with cholangitis, complicated by Clostridium perfringens septicaemia and massive intravascular haemolysis. Clostridium perfringens septicaemia is a rare but well-known cause of massive intravascular haemolysis. Here we review 40 similar cases published since 1990. Most cases involve immunocompromised patients with underlying haematological disorder (22.5%), pancreatic or gastric cancer (12.5%) and÷or diabetes (30.0%). Focus of infection is mostly hepatobiliary (45.0%), intestinal or gynaecological after invasive procedure. Eighty percent of reviewed cases did not survive; the median time between admission and death was only eight hours. If an attempt was made to remove the focus of infection (i.e. by drainage of liver abscess, cholecystectomy, hysterectomy or ERCP), this proved to be a strong prognostic indicator of survival. However, in many of the cases the patient had already gone into shock or died before a diagnosis could be made. In severely ill patients with fever and haemolysis on the emergency department Clostridium perfringens septicaemia should always be considered, since early antibiotic treatment and if possible removal of the focus of infection can rescue patients from an otherwise fatal outcome.

[Diagnostic image (391). A man with fever and urticaria after a trip to Uganda]

A 35-year-old man presented with fever and severe urticaria after visiting Uganda. His symptoms were caused by acute invasive schistosomiasis, also known as Katayama fever.

[Granulomatous mastitis: a rare cause of breast swelling]

Three women, aged 37, 39 and 29 years, presented with unilateral painful swelling of the breast. Ultrasound revealed inflammation with abscess formation. Histological biopsies contained granulomatous tissue without necrosis. Corynebacterium species were cultured in the first two patients. All 3 patients were diagnosed with granulomatous mastitis and were successfully treated with doxycycline. Granulomatous mastitis is a rare disorder that may mimic breast carcinoma. It occurs most frequently in fertile women. Diagnosis is based on histological biopsy which shows granulomas without necrosis, while other causes of granulomatous inflammation, especially tuberculosis, have been excluded. The aetiology is not fully understood. It is hypothesised that the granulomatous mastitis is caused by a type IV allergic reaction. Recently an association with Corynebacterium species was suggested. Best practice treatment methods are unclear. Most patients are treated with surgical intervention and steroids, but the rate of recurrence is high (50%). Treatment with doxycycline must be considered in patients with cultured Corynebacterium species.

Camurati-Engelmann disease (progressive diaphyseal dysplasia) in a Moroccan family

We report on a 46-year-old mother of Moroccan origin, suffering mainly from painful, swollen legs, and her 26-year-old son who had experienced intense pain in his legs, without fever, for approximately 3 years. They did not have dysmorphic features or abnormal gaits. Radiographic studies of the mother revealed diaphyseal sclerosis of the tibia and spondylosis of the thoracal and lumbar vertebrae. The son had sclerosis of the diaphyses of the metacarpalia of the left hand, the femur and the fibula. The other parts of the skeleton were normal. Several osteosclerotic/hyperostotic disorders, such as melorheostosis (present mostly in sporadic cases and affecting lower extremities) and van Buchem's disease (autosomal recessive and commonly affecting the mandible) were considered as a diagnosis in the proposita. However, similar symptoms in the son of the proposita suggested an autosomal dominant inheritance pattern. This brought us to the diagnosis of progressive diaphyseal dysplasia (PDD) or Camurati-Engelmann disease (CED), an autosomal dominant disorder characterized by limb pain, reduced muscle mass, weakness, a waddling gait, progressive periosteal and endosteal sclerosis of the diaphyses of the long bones and sclerosis of the skull base. Mutations in the transforming growth factor (TGF)-beta1 gene on chromosome 19q13.1 have been reported to cause this disorder. The diagnosis of PDD/CED in this family was confirmed at the molecular level by detection of a C-to-T transition at position 466, leading to an arginine-to-cysteine amino acid change (position 156) in exon 2 of the transforming growth factor-beta1 (TGFB1) gene.

Impact of net pen aquaculture on lake water quality

A 3-year study was conducted by the U.S. Army Corps of Engineers assessing water quality related impacts of aquaculture of 250,000 channel catfish (Ictalurus punctatus) in floating net pens in the Rock Creek Arm of Lake Texoma, Oklahoma/Texas. Five large nylon nets suspended from a floating framework of galvanized metal anchored in open water 100 m offshore made up the net pens with fish stocking densities varying from 88 to 219 fish/m3. Water quality sampling was conducted biweekly from April to September and monthly from October to March at three locations. On all sampling dates field measurements of water temperature, pH, dissolved oxygen, and conductivity were recorded at 1 m depth intervals and water samples were collected at a depth of 0.6 m and near the bottom of the water column at each site. Sample analyses included: total alkalinity, total hardness, turbidity, chloride, sulfate, orthophosphate, total phosphorus, nitrate-N, nitrite-N, total Kjeldahl nitrogen, total organic carbon, dissolved organic carbon, biochemical oxygen demand, and chlorophyll a. The results showed statistically significant decreases in water temperature and dissolved oxygen and significant increases in field conductivity in surface waters near the net pens relative to other sampling sites. The most dramatic water quality effect observed during the study was decrease in dissolved oxygen levels near the net pens following lake turnover in the second year.

Airport malaria: report of a case and a brief review of the literature

We report a case of Plasmodium vivax malaria in a patient who had not visited an endemic area. The ways in which malaria can be transmitted in non-endemic areas are discussed. By the elimination of other possibilities, the diagnosis of airport malaria was made. Airport malaria is a rare and often initially overlooked diagnosis. Since 1969, some 89 cases of airport malaria have been reported.

[Diagnostic image (116). A man with acute exanthema. Epstein-Barr virus infection]

A 19-year-old man presented with a rash, several days after antibiotic therapy for pharyngitis. Such a rash is highly suggestive of an acute viral infection; Epstein-Barr virus infection was confirmed serologically.

Chatters on the Internet: a special target group for HIV prevention

This study examined characteristics of men who use gay chat boxes on the Internet, including dating behaviour and sexual risk-taking with sex partners who were initially met through chatting. Men on chat boxes were asked to complete a brief questionnaire on the Internet. The questionnaire contained questions on demographics, chatting-related variables, and dating and risk-taking sexual behaviour. The results show that a large majority of the 190 respondents reported actual encounters as well as sex with men who were initially met through chatting. Almost 30% of the respondents who engaged in sex with chat dates reported inconsistent safe sexual behaviour. The level of unprotected sex increased as the number of sex partners who were met through chatting increased. These results suggest that chatters on the Internet may be a new target group for HIV prevention. Further study is needed to gain insight into the feasibility of prevention efforts for this target group.