Differential topochemistry of three cationic amino acid transporter proteins, hCAT1, hCAT2 and hCAT3, in the adult human brain.

The cellular uptake of L-arginine and other cationic amino acids (such as L-lysine and L-ornithine) is mainly mediated by cationic amino acid transporter (CAT) proteins. Despite the important roles of cationic amino acid transporters for normal brain functioning and various brain diseases there is currently only fragmentary knowledge about their cellular and regional distribution patterns in the human brain. We mapped the immunohistochemical localization of human cationic amino acid transporters 1, 2 and 3 (hCAT1, 2, and 3) throughout five adult human brains and found a wide but uneven distribution of these transporters. All three hCAT1s were mainly localized in neurons, but were also found in numerous astrocytes, oligodendrocytes, plexus choroideus epithelial cells, and small blood vessels. The highest density of hCAT expressing neurons was observed in the hypothalamus, in some areas of the cerebral cortex, the thalamic reticular nucleus and the caudate nucleus, whereas weak to moderate expression was detected in the hippocampus, the prefrontal cortex (hCAT1 only), pons, brain stem and cerebellum. In contrast to what has been found in rodent brain, we detected hCAT2 and hCAT3 also in astrocytes. Overall, each hCAT has its characteristic, individual cerebral expression patterns, which, however, overlap with the others.

Ghrelin treatment increases receptor-bound leptin in healthy and endotoxemic obese Lewis rats.

Obese patients with sepsis have higher morbidity and mortality rates than normal weight subjects. One crucial factor is the disease-associated disturbed energy balance. Ghrelin is an orexigenic peptide, mainly produced in the stomach. Leptin is an adipose-tissue derived peptide, circulating as free (fl) and receptor-bound protein (bl) acting antagonistically to ghrelin's effects on food intake. In the present study we tested the weight dependent influence of an intravenous (i.v.) ghrelin injection on leptin levels as well as hepatic protein expression in healthy and endotoxemic rats. Male Lewis rats were randomly divided into four diet-induced obese and four normal weight groups. Application of either ghrelin or NaCl was followed by a bolus injection of LPS or NaCl. Blood was collected at five time points (up to 24 h) to measure fl and bl by radioimmunoassay. Furthermore, hepatic leptin, leptin receptor and ghrelin expression were investigated immunohistochemically. Results revealed a late shift from high elevated fl to significantly enhanced levels of bl in ghrelin treated obese animals. Both fl and bl levels remained unaffected in lean rats. The findings suggest that an increased body weight of the treated animals is associated with altered hormone levels after therapeutic interventions with ghrelin.

Diet-induced obesity alters behavior as well as serum levels of corticosterone in F344 rats.

Obesity is an increasing socio-economic health problem. Diet-induced obese (DIO) rodents are widely used as a model of obesity in humans. However, there is no comprehensive data about the behavioral phenotype of DIO rodents. Therefore, the aim of the present study was to determine whether a high-fat-diet changes behavioral patterns of DIO Fischer 344 (F344) rats in comparison with lean littermates. The behavioral tests (homecage, holeboard, social interaction, and hotplate) were performed in 28 normal-weight and 28 male DIO F344 rats (mean age: 16 weeks) and revealed a significantly higher level of anxiety- and aggression-related parameters in obese rats, whereas their pain threshold was significantly lower. Fitting to a different behavioral response, basal corticosterone levels (measured by RIA) of obese animals were significantly elevated (16.0ng/ml vs. 12.5ng/ml; p<0.01). We conclude that obese rats differ in various aspects from their lean littermates. The altered behavioral characteristics displayed by DIO F344 rats have to be considered in further experiments involving DIO rodents.

Prospective analysis of the long-term effect of teaching breast self-examination and breast awareness.

Breast cancer is the most common cancer in women in the industrialized world and a leading cause of death. Breast self-examination (BSE) is one of the methods for an early detection of breast cancer. In the present study the effectiveness of a campaign promoting BSE and breast awareness was analysed. Seminars were conducted in 2003 in Lower Saxony, Germany by a female gynaecologist and a social pedagogue and included a lecture, an individual training in BSE in a separate room and a talk about the importance of regular BSEs. Questionnaires were handed out immediately after the seminar and were sent by post 1 year later. Attendance of the seminar resulted in a significantly higher percentage of monthly BSEs (21.4% before vs. 61.9% after the teaching). Furthermore, 92.1% of the women who did not perform a monthly BSE stated that at least they examined their breasts more frequently after attending the seminar. The data demonstrate that the seminars in BSE had profound effects on the compliance of women in carrying out BSE regularly and correctly, without influence of age or education.

In vivo and in vitro evidence for a hepatic modulation of the leptin signal in rats.

BACKGROUND: Leptin is primarily secreted by the adipose tissue. It binds not only to hypothalamic structures involved in energy regulation but also to many peripheral tissues including the liver. Leptin circulates in free and receptor-bound forms. Both components are differentially regulated under various pathophysiological conditions and serve different physiological functions. They are released from adipose tissue but previous data suggest an additional formation outside the fat compartment. Here we tested the contribution of the liver in binding and modulating leptin in the circulation. MATERIALS AND METHODS: In vivo experiments were performed with radioactive labelled leptin with and without pretreatment with unlabelled leptin in freely moving, chronic intravenously cannulated male rats. Livers were investigated by immunohistochemistry and in situ hybridization and immunoblotting was performed, followed by ex vivo liver perfusion studies with human recombinant leptin. RESULTS: In in vivo experiments radioactively labelled leptin (at low concentrations) is avidly bound to rat liver (greater than 80% of basal serum values 90 min following i.v. infusion). Pre-treatment with excess of unlabelled leptin in vivo revealed a rapid hepatic down-regulation of leptin receptor isoforms when tested by in situ hybridization, immunoblotting or immunohistochemistry. Ex vivo perfusion of rat liver with human recombinant leptin induced a dose- and time-dependent formation of receptor-bound leptin in the perfusate. CONCLUSIONS: The present data support an active role of the liver in the modulation of the leptin signal through different regulation of the soluble leptin receptor, the bound and free forms of the hormone, which may have important implications for leptin's central efficacy and the development of 'leptin resistance'.

Applied anatomy of the superior vena cava-the carina as a landmark to guide central venous catheter placement.

BACKGROUND: Cardiac tamponade is a serious complication of central venous catheter (CVC) insertion. Current guidelines strongly advise that the CVC tip should be located in the superior vena cava (SVC) and outside the pericardial sac. This may be difficult to verify as the exact location of the pericardium cannot be seen on a normal chest x-ray. The carina is an alternative radiographic marker for correct CVC placement, suggested on the basis of studies of embalmed cadavers. METHODS: We set out to confirm this radiographic landmark in 39 fresh cadavers (age 58.4 (3.4) (mean and SE) yr) and to compare the results with those from ethanol-formalin-fixed cadavers. RESULTS: We found that the carina was 0.8 (0.05) cm above the pericardial sac as it transverses the SVC. In no case was the carina inferior to the pericardial reflection and our study confirmed the previous findings. All the measured distances were significantly greater in fresh cadavers. CONCLUSIONS: We confirm that the carina is a reliable, simple anatomical landmark that can be identified in vivo for the correct placement of CVCs outside the boundaries of the pericardial sac.

Seminar in breast self-examination for female medical students integrated into a human gross anatomy course.

A breast self-examination (BSE) seminar for first-year female medical students is presented and a single-gender approach for other subjects in the medical curriculum is discussed. In 1999 a small group seminar on BSE was offered at the Hannover Medical School to female medical students as part of their curriculum in human gross anatomy. An evaluation questionnaire was answered by 94 students (87% of participants). Frequencies of answers to two open questions were used as indicators of: 1) the acceptance of a single-gender course and 2) an increased awareness of breast cancer prevention. A linear regression analysis was carried out to identify the most important predictors for the global course evaluation and a heightened interest in breast cancer prevention. The mean global rating of the seminar was 13.8 (minimum: 1 point; maximum: 15 points). Factors that significantly influenced the global rating were the course atmosphere, the teacher's enthusiasm, and the professional interest of the students. An increased concern for breast cancer prevention was significantly dependent on the professional interest and the self-awareness of the women. The results suggest that there is a need for single-gender seminars in academic medicine and that instruction of female students in BSE is an ideal subject for this approach. Because of the prevalence of breast cancer, it is recommended that such a seminar become an integral part of the preclinical curriculum for all female medical students.

Secretion of free and protein-bound leptin from subcutaneous adipose tissue of lean and obese women.

Leptin circulates as a free (FL) and a protein-bound (BL) form, with the soluble leptin receptor (LR) as an important binding compound. Here we measured these components of leptin in serum and in the incubation medium of sc adipose tissue in healthy lean (n = 10) and obese (n = 13) female subjects using recently developed specific RIA systems. In addition, immunostaining for FL, BL, and LR in adipose tissue was performed. Serum FL levels were increased in the obese subjects (P < 0.0001), whereas BL and LR concentrations in serum of lean and obese subjects were similar. Both FL and BL were secreted from human preadipocytes and increased in parallel to the differentiation of the cells. In sc fat cell explants LR antibodies predominantly stained the fat cell membrane, whereas FL and BL antibodies revealed intracytoplasmatic adipocyte staining. The release of FL, BL, and LR from adipose tissue was increased in obese compared with lean subjects (P < 0.005 for FL; P < 0.02 for BL, and P < 0.01 for LR). In summary, fat cells are capable of releasing not only FL, but also BL and LR.

Differential effects of neuropeptide Y (NPY) on leukocyte subsets in the blood: mobilization of B-1-like B-lymphocytes and activated monocytes.

Sympathetic nervous system activation mobilizes leukocytes but it is unknown whether the concomitant neuropeptide Y (NPY)-release also alters blood leukocyte counts. Using chronic intravenous (i.v.) cannulation of freely moving rats and flow cytometry, time-, dose- and subset-specific effects of NPY on blood leukocytes were investigated 1-15 min after injection: High-dose NPY increases leukocytes numbers by preferentially mobilizing CD4(+) T-cells, activated NKR-P1A(+) monocytes and NK-cells. Low-dose NPY significantly decreases B-lymphocyte and NK-cell numbers. Furthermore, NPY dose-dependently mobilizes a previously undetected IgM(low)CD5(+)CD11b(+) B-cell subpopulation in rats ("B1-like" B-lymphocytes). These data suggest a role for the sympathetic neurotransmitter NPY in neuroimmune alterations in vivo.

Surgery as primary treatment in patients with liver metastases from carcinoid tumors: a retrospective, unicentric study over 13 years.

BACKGROUND: The heterogeneous nature of carcinoid tumors makes it difficult to develop a standardized treatment strategy for the primary tumor itself and for probable liver metastases. However, prolongation of the 5-year survival rate (5-ysr) and amelioration of the incapacitating symptoms after resection of the primary tumor and its metastases demonstrate that surgical intervention must be the treatment of choice in these tumors. METHODS: The data of 31 patients (17 patients with midgut carcinoids, 10 patients with an endocrine carcinoma (carcinoid) of the pancreas, and 4 patients with carcinoids of the lung) who underwent liver operation for metastatic carcinoid tumors between 1983 and 1996 were analyzed, with special regard to factors influencing postoperative survival. RESULTS: Ten patients underwent curative resection (5-ysr, 86%), and palliative operations were performed in 21 patients (5-ysr, 26%). The overall 5-ysr was 47%, with a mean postoperative follow-up of 3.5 years (range, 4 months to 10.8 years). Postoperative morbidity rate was 13%. Size of liver metastases, radicality of the operation and localization of the primary tumor were factors influencing postoperative survival. CONCLUSIONS: Surgery for metastatic carcinoid tumors may be curative or palliative, with a potential for cure in some cases and prolongation of survival and amelioration of symptoms in the majority of patients.

Evaluation of the medical curriculum: why, when, by whom and for whom should questionnaires be used.

The undergraduate medical curriculum has been modified or even totally reorganized in many countries in recent years, and there are plans to make departmental budgets and the salaries of university professors partially dependent on the outcome of teaching. Questionnaires are often used in such situations as a means of curriculum evaluation. Based on our own experience such evaluations should be done not only during and immediately after a course in the curriculum, but also at later time points, e.g., at the end of the undergraduate and also the postgraduate phase. The clinical relevance of lectures and courses can only be graded adequately after some years of clinical experience. Gross anatomy was graded top at all time points evaluated and reached higher levels of 'clinical relevance' than other typical preclinical and even clinical subjects. Efforts should be made to obtain a high response rate for representative results. After modifying parts of a course detailed questionnaires should also include space for students' suggestions. The results of such evaluations are not only relevant to the head of department as feedback on the individual lecturers but also important for the curriculum committee and the dean. Anatomists should utilize these evaluations to improve teaching.

Morphology and immunology of the human palatine tonsil.

At the surface of the respiratory and digestive organs the organism first comes into contact nasally and orally with various foreign agents and substances in the air and in food. The palatine tonsils are located at the centre of this strategic region. Immunological processes, both humoral and cellular, are initiated in the different specialised compartments of the palatine tonsils, such as the crypt epithelium, lymphoid follicles and extrafollicular region. Each compartment has a typical composition of lymphocytes and dendritic cell subsets. This review summarises current data on the anatomy, histology, and pathology of the human palatine tonsils, describes their fundamental immunological functions, and provides insight into the various interactions involved in the initiation of immune responses. The palatine tonsil is the only easily accessible human lymphoid organ and is often taken as an example for lymphoid organs. Although affections of the palatine tonsils constitutes an essential part in the clinical routine, it is still controversial whether tonsillectomy is of general benefit. This is of increasing importance since it has been discovered in the last few years that the palatine tonsils are reservoir and replication sites of HIV.

Leukocyte mobilization induced by hypervolemia is due to a combined alpha- and beta-adrenoceptor activation.

A phenomenon of leukocytosis induced by hypervolemic stress was discovered. Although a single injection of 350 microl of saline (equivalent to approx. 70 ml in humans, 1 ml/kg of body weight) did not have an effect on the leukocyte counts in long-term intravenously cannulated, freely behaving rats, a single injection of 750 microl of saline (equivalent to approx. 150 ml in humans, 2.1 ml/kg) induced rapid leukocytosis of 160% within 1 minute followed by a gradual increase up to 180% after 1 hour. Measurement of serum norepinephrine concentration revealed a significant increase in rats of the hypervolemic group, compared with those of the low volume group. Pretreatment with either the beta-adrenoceptor antagonist nadolol or the selective alpha2-adrenoceptor antagonist yohimbine prevented both leukocyte peaks in the high volume group, suggesting a combined receptor activation. This critical dependence of leukocyte counts on changes in blood volume should be taken into consideration in experiments with laboratory animals (the quantity of volume applications can falsify results of experiments).

The carina as a landmark in central venous catheter placement.

Location of the tip of a central venous catheter (CVC) within the pericardium has been associated with potentially lethal cardiac tamponade. Because the pericardium cannot be seen on chest x-ray (CXR), an alternative radiographic marker is needed for correct placement of CVCs. The anatomy of the region was studied in 34 cadavers. The carina was a mean (SEM) distance of 0.4 (0.1) cm above the pericardial sac as it transverses the superior vena cava (SVC). In no case was the carina located below the pericardial sac. The carina is a reliable, simple anatomical landmark for the correct placement of CVCs. In almost all cases, the carina is radiologically visible even in poor quality, portable CXRs. CVC tips should be located in the SVC above the level of the carina in order to avoid cardiac tamponade.

Stereological quantification of carboxyfluorescein-labeled rat lung metastasis: a new method for the assessment of natural killer cell activity and tumor adhesion in vivo and in situ.

The function of natural killer (NK) cells is often studied by assessing in vitro levels of NK cell mediated lysis of target cells, or by assessing in vivo levels of lung tumor cell retention or metastatic colonization of intravenously injected tumor cells. However, these methods do not permit direct quantification and visualization of NK cells and their targets in vivo and in situ. Here, a new approach is described to visualize effector-to-target interactions as well as to estimate total numbers of targets in the lung, in vivo and in situ. MADB106 tumor cells were vitally labeled using carboxyfluorescein (CFSE) and intravenously (i.v.) injected into Fischer 344 rats (10(6) cells/rat). This mammary adenocarcinoma derived cell line is syngeneic to the inbred Fischer 344 rat and highly sensitive to NK cell activity in vivo. Effector-to-target interactions were visualized by immunostaining. Using the optical fractionator method, total numbers of CFSE-labeled MADB106 tumor cells were estimated in the left lung of the animals 5 min after tumor inoculation. To further demonstrate the usefulness of this approach in reflecting in vivo processes, rats were inoculated with MADB106 cells and simultaneously with a single i.v. bolus of either 1 microg/kg adrenaline or saline. Both lungs were removed 5 min later. Adrenaline caused a significant 80% reduction in the total number of lung CFSE-labeled MADB106 tumor cells, suggesting a rapid modulation of metastasis by stress hormones. This new approach facilitates the monitoring of effector-to-target interactions and the quantification of immune cell function or tumor adhesion in vivo and in situ.

Modulation of innate immune functions by intracerebroventricularly applied neuropeptide Y: dose and time dependent effects.

Centrally applied neuropeptide Y (NPY) interacts with the autonomic nervous system and the hypothalamo-pituitary-adrenal (HPA) axis activity. Since these physiological systems have been shown to modulate innate immune functions, the effects of intracerebroventricular (i.c.v.) NPY administration on leukocyte subsets in the blood, spleen and intravascular pool of the lung, blood granulocyte chemiluminescence response, and splenic natural killer (NK) cell-mediated lysis were studied in Lewis rats. Concentration-dependent NPY effects were tested at 15 min and 24 h post i.c.v. injection at dosages of 10(-6) M, 10(-9) M, and 10(-12) M. Time dependent effects were investigated at 15 min, 1 h and 24 h after i.c.v. administration of 10(-9) M NPY. Compared to saline controls, an increased number of granulocytes and NK cells in the blood, associated with a decreased granulocyte function and NK cytotoxicity was observed 15 min following NPY infusion. This initial immunosuppression was followed by long lasting stimulatory effects of NPY on the functional capacity of both cell populations when tested at 1 h and 24 h. The dosage of i.c.v. 10(-6) M NPY produced no changes, whilst 10(-9) M produced maximal, and 10(-12) M still significant effects. Results provide evidence that centrally applied NPY influences innate immunity in a dose and time dependent fashion. Cell mobilization from the vascular marginal pool is likely to be an underlying mechanism for the initial immunosuppression.

Brain NPY Y1 receptors rapidly mediate the behavioral response to novelty and a compartment-specific modulation of granulocyte function in blood and spleen.

Neuropeptide Y (NPY) alters behavioral activity and innate immune functions of rats within minutes of intracerebroventricular (i.c.v.) application. Using combinations of the Y1-5a,b(6) agonist NPY, the Y1,3,5 agonist [Leu31-Pro34]NPY (LP-NPY), and the selective Y1 antagonist BIBP3226 (BIBP), we investigated whether the NPY-Y1 receptor (Y1R) subtype regulates NPY-induced behavioral and immunological effects at 15 min after i.c.v. application. Administration of both NPY and LP-NPY decreased rearing activity in the open field and suppressed granulocyte function in the blood. These effects were blocked by BIBP pre-treatment. In contrast to the blood, NPY and BIBP+NPY treatments stimulated granulocyte function within the splenic compartment. In addition, a blood leukophilia composed of granulocytes and NK cells was induced by NPY only. We conclude that the tested early effects of NPY are mediated by either the Y1R (rearing, blood granulocyte function), or a non-Y1R (splenic granulocyte function), or by a combined receptor activation (leukocyte mobilization). Furthermore, the immunological effects of NPY demonstrate compartment specificity.

Centrally applied NPY mimics immunoactivation induced by non-analgesic doses of met-enkephalin.

Neuropeptide Y (NPY) and endogenous opioids (EOPs) such as methionine-enkephalin (Met-enk) regulate similar physiological responses, but it is not known whether nociceptive and immune responses also show analogy after intracerebroventricular (i.c.v.) application. Dose-response studies show that Met-enk stimulates the blood granulocyte and splenic natural killer (NK) cell function of Lewis rats at a low dose (10(2) ng/kg, i.c.v.), whereas a high dose (10(5) ng/kg) causes suppression of innate immune functions associated with analgesia in the hot-plate test. At 15 min, 1 h and 24 h after i.c.v. application, both Met-enk (10(2) ng/kg) and NPY (1 ng/kg) produced similar effects: An initial suppression of innate immune function was followed by a long lasting stimulatory action on cell functions and serum interleukin-6 (sIL-6) levels. Thus, central NPY application resembles Met-enk-induced immunostimulation at doses not affecting nociception, suggesting an involvement of both peptides in shaping stress-induced immunomodulation of the non-analgetic form, possibly via activation of a common immunomodulatory effector mechanism.

Therapy of locally unresectable pancreatic carcinoma: a randomized comparison of high dose (6000 rads) radiation alone, moderate dose radiation (4000 rads + 5-fluorouracil), and high dose radiation + 5-fluorouracil: The Gastrointestinal Tumor Study Group.

One-hundred-ninety-four eligible and evaluable patients with histologically confirmed locally unresectable adenocarcinoma of the pancreas were randomly assigned to therapy with high-dose (6000 rads) radiation therapy alone, to moderate-dose (4000 rads) radiation + 5-fluorouracil (5-FU), and to high-dose radiation plus 5-FU. Median survival with radiation alone was only 51/2 months from date of diagnosis. Both 5-FU-containing treatment regimens produced a highly significant survival improvement when compared with radiation alone. Forty percent of patients treated with the combined regimens were still living at one year compared with 10% of patients treated with radiation only. Survival differences between 4000 rads plus 5-FU and 6000 rads plus 5-FU were not significant with an overall median survival of ten months. Significant prognostic variables, in addition to treatment, were pretreatment performance status and pretreatment CEA level.