Dominance of virus-specific CD8 T cells in human primary cytomegalovirus infection

Cellular immune responses are of high importance in initiating and maintaining immunity against virus infections. Whereas the cellular immune response during persistent cytomegalovirus (CMV) infection is well assessable, the individual contribution of CD4 and CD8 T cell responses during primary infection has not been described. A novel whole-blood assay, which relies on the flow-cytometric detection of antigen-induced cytokine expression, was used to characterize CMV-specific CD4 and CD8 T cell responses during primary infection of CMV seronegative recipients of a renal allograft from a CMV seropositive donor. These T cell responses were compared with long-term CMV-positive patients with known history of transplantation-related seroconversion. Results were further correlated to CMV load and serum IgG and IgM. The long-term seroconverted patients consistently showed a dominant CMV-specific CD4 T cell response (median frequencies: CD4, 1.12% [range, 0.35 to 8.10%] versus CD8 0.13% [range, <0.05 to 0.55%]). In contrast, during primary infection, the cellular immune response is strongly dominated by CMV-specific CD8 T cells (median peak frequencies: CD4, 1.24% [range, 0.21 to 1.60%] versus CD8, 2.47% [range, 1.34 to 6.67%]). Upon receipt of ganciclovir, viral load as well as CMV-specific CD8 responses decreased. The frequency of the respective CD4 T cells fluctuated during decrease of CMV load and became dominant over CMV-specific CD8 T cell responses. These results are consistent with the view of an effective direct antiviral activity of CD8 T cells, which is most critical during periods of high viremia. Later on during persistent infection, CD4 T cells dominate the immune response to support the state of antiviral immunity.     

Biomaterials as Scaffold for Bone Tissue Engineering

Abstract Almost 20 years after the invention of tissue engineering, autogenous bone grafting has remained the favored strategy for the treatment of bone defects. As an alternative, a vast variety of bone substitutes has been developed and is available for clinical use. The ongoing search for bone substitutes, however, reflects the limitations imposed to both autogenous and allogenous bone grafts as well as to bone substitute materials. The concept of tissue engineering holds great promise for the future treatment of osseous defects. Research in this interdisciplinary field is carried out to find a way of producing biologic substitutes as functional tissue replacement. For this, functionally active cells are applied on supporting scaffolds under controlled stimulation with growth factors. Scaffolds are temporary matrices for bone growth and provide a specific environment and architecture for tissue development. Ideally, scaffolds favor cellular attachment, growth and differentiation in vitro and in vivo. Especially ceramics and biodegradable polymers are widely used and have been tested in various animal studies. Yet, to allow for precise production of specific custom-made scaffolds, rapid prototyping (RP) techniques have recently drawn a lot of attention. Using these methods scaffolds with a predefined, well-controlled internal and external architecture mimicking the structure of natural bone can be generated. Although biocompatibility of the materials used in the process and the structural resolution that can be technically achieved so far limit the range of use, rapid manufacturing techniques do offer great opportunities to generate suitable scaffolds for bone tissue engineering in the near future.     

Pulmonary surfactant dysfunction in pediatric cystic fibrosis: Mechanisms and reversal with a lipid-sequestering drug

Background

Airway surfactant is impaired in cystic fibrosis (CF) and associated with declines in pulmonary function. We hypothesized that surfactant dysfunction in CF is due to an excess of cholesterol with an interaction with oxidation.

Posttraumatic vasospasm: the epidemiology, severity, and time course of an underestimated phenomenon: a prospective study performed in 299 patients

OBJECT: The purpose of this prospective study was to evaluate the cumulative incidence, duration, and time course of cerebral vasospasm after traumatic brain injury (TBI) in a cohort of 299 patients. METHODS: Transcranial Doppler (TCD) ultrasonography studies of blood flow velocity in the middle cerebral and basilar arteries (VMCA and VBA, respectively) were performed at regular intervals during the first 2 weeks posttrauma in association with 133Xe cerebral blood flow (CBF) measurements. According to current definitions of vasospasm, five different criteria were used to classify the patients: A (VMCA > 120 cm/second); B (VMCA > 120 cm/second and a Lindegaard ratio [LR] > 3); C (spasm index [SI] in the anterior circulation > 3.4); D (VBA > 90 cm/second); and E (SI in the posterior circulation > 2.5). Criteria C and E were considered to represent hemodynamically significant vasospasm. Mixed-effects spline models were used to analyze the data of multiple measurements with an inconsistent sampling rate. Overall 45.2% of the patients demonstrated at least one criterion for vasospasm. The patients in whom vasospasm developed were significantly younger and had lower Glasgow Coma Scale scores on admission. The normalized cumulative incidences were 36.9 and 36.2% for patients with Criteria A and B, respectively. Hemodynamically significant vasospasm in the anterior circulation (Criterion C) was found in 44.6% of the patients, whereas vasospasm in the BA-Criterion D or E-was found in only 19 and 22.5% of the patients, respectively. The most common day of onset for Criteria A, B, D, and E was postinjury Day 2. The highest risk of developing hemodynamically significant vasospasm in the anterior circulation was found on Day 3. The daily prevalence of vasospasm in patients in the intensive care unit was 30% from postinjury Day 2 to Day 13. Vasospasm resolved after a duration of 5 days in 50% of the patients with Criterion A or B and after a period of 3.5 days in 50% of those patients with Criterion D or E. Hemodynamically significant vasospasm in the anterior circulation resolved after 2.5 days in 50% of the patients. The time course of that vasospasm was primarily determined by a decrease in CBF. CONCLUSIONS: The incidence of vasospasm after TBI is similar to that following aneurysmal subarachnoid hemorrhage. Because vasospasm is a significant event in a high proportion of patients after severe head injury, close TCD and CBF monitoring is recommended for the treatment of such patients.     

Evolution of health-related quality of life two to seven years after retropubic radical prostatectomy: evaluation by UCLA prostate cancer index

To determine changes in health-related quality of life (HRQOL) in patients treated with retropubic radical prostatectomy (RP) between two and seven years after surgery. A questionnaire from the University of California Los Angeles Prostate Index was sent to 142 patients previously treated with retropubic RP as mono-therapy for clinically localized prostate cancer. Patients were divided into five groups according to time from surgery. Demographics, clinical and pathological characteristics of patients were compared between these groups. Correlation coefficients controlled for age at the time of questionnaire between HRQOL scores and time from RP were assessed. A total of 105 patients (74%) returned the questionnaire. The mean time from surgery was 48 months (range 25–84). Demographics, clinical and pathological characteristics of patients were not statistically different between time groups. Several recoding items were found to decrease significantly with the time from RP including physical functioning, role limitations due to physical health problem, vitality, and general health. In contrary, urinary, bowel and sexual scores were not significantly correlated to time from RP. Although sexual, urinary and bowel scores seem to remain stable from 2 to 7 years following RP, general health appears to significantly deteriorate with time after RP, independent of the patient’s age at the time of the questionnaire.     

Palliation of malignant rectal obstruction with self-expanding metal stents

BACKGROUND: Surgical management of patients with metastatic or recurrent rectal cancer remains controversial. Self-expanding metal stents are increasingly used for palliative treatment of advanced tumors, although long-term results are not yet available. METHODS: Between 1996 and 2003, 521 patients underwent surgery for rectal neoplasms. In the same time period, self-expanding metal stents were used for palliation of 34 patients with malignant rectal obstruction and incurable disease. The outcome of the patients was analyzed retrospectively. RESULTS: Rectal stents were successfully placed in 33 of 34 patients (97%) without major complications. Early failure occurred in 7 patients (21%) because of stent migration, pain, or incontinence. Long-term success with a mean patency of 5.3 months was observed in 26 patients (79%), but restenting was required in 2 patients. Despite the initial success of stenting, a colostomy was created in 2 other patients after 3.4 months and 9.2 months because of incontinence and rectovesical fistula. Overall, 6 of 33 patients (18%) underwent palliative surgery because of early complications (n = 4) or long-term failure of stent treatment (n = 2). CONCLUSIONS: Self-expanding metal stents are useful to avoid a colostomy in selected patients with incurable rectal cancer and limited life expectancy. Nonetheless, a considerable number (18%) of patients will require surgical palliation because of failure of stent treatment.     

Changes of adiponectin oligomer composition by moderate weight reduction

Adiponectin affects lipid metabolism and insulin sensitivity. However, adiponectin circulates in three different oligomers that may also have distinct biological functions. We aimed to analyze the role of these oligomers in obesity and lipid metabolism after weight reduction. A total of 17 obese volunteers (15 women and 2 men) participated in a weight reduction program. Individuals were characterized before and after 6 months of a balanced diet. Adiponectin was determined by enzyme-linked immunosorbent assay, and oligomers were detected by nondenaturating Western blot. BMI decreased (35.1 +/- 1.2 to 32.8 +/- 1.1 kg/m(2), P < 0.001), which was associated with an improved metabolite profile. Total adiponectin increased from 5.3 +/- 0.5 to 6.1 +/- 0.6 microg/ml (P = 0.076). High (HMW) and medium molecular weight (MMW) adiponectin oligomers significantly increased during weight reduction (HMW: 0.37 +/- 0.07 to 0.4 +/- 0.08 microg/ml, P = 0.042; MMW: 2.3 +/- 0.2 to 2.9 +/- 0.3 microg/ml, P = 0.007), while low molecular weight (LMW) did not significantly change. Body weight inversely correlated with HMW (r = -0.695, P = 0.002) and positively with LMW (r = 0.579, P = 0.015). Interestingly, HDL cholesterol and HMW were strongly correlated (r = 0.665, P = 0.007). Indeed, HMW and free fatty acids before weight reduction predicted approximately 60% of HDL changes during intervention. In conclusion, weight reduction results in a relative increase of HMW/MMW adiponectin and a reduction of LMW adiponectin. Total adiponectin and especially HMW adiponectin are related to circulating HDL cholesterol.