Expression of apoptosis regulatory proteins p53 and Bcl-2 in skin of patients with chronic renal failure on maintenance haemodialysis

BACKGROUND: Chronic renal failure results in multi-organ system derangement including cardiovascular, gastrointestinal, neurological, endocrinal, blood and dermatological abnormalities. Maintenance of skin homeostasis requires a delicate balance between proliferation, differentiation and apoptosis. p53 and Bcl-2 proteins play a central role in the regulation of apoptosis. OBJECTIVE: Evaluation of the expression of apoptosis regulatory proteins p53 and Bcl-2 in apparently normal skin of patients, with chronic renal failure on maintenance haemodialysis, with respect to their role in the apoptotic process. METHODS: Biopsy specimens were obtained from 10 patients with chronic renal failure on maintenance haemodialysis, as well as seven age-matched control subjects. Computer-assisted image analysis was employed to measure epidermal thickness in H&E-stained sections. Immunoperoxidase technique was also used to demonstrate p53 and Bcl-2 proteins and the TUNEL technique for detection of apoptotic cells in these specimens. RESULTS: The mean epidermal thickness was significantly higher (P < 0.0001) in patients than controls. Meanwhile, no apoptotic cells were detected in the epidermis of patients. On the other hand, a statistically significant difference was observed in both p53 (P = 0.0001) and Bcl-2 expression (P = 0.0003) when comparing patients and controls. Expression of p53 (2.74 +/- 0.84) and Bcl-2 (3.45 +/- 1.35) proteins was higher in skin samples obtained from patients with chronic renal failure and on maintenance haemodialysis than those from control cases (0.5 +/- 0.96 and 0.8 +/- 0.6, respectively). Moreover, Bcl-2 expression in patients was observed in basal as well as squamous cell layers of skin, whereas in control subjects it was confined to the basal cell layer only. CONCLUSION: These findings suggest that an alteration in the proliferation/apoptosis balance may be present in the skin of such patients.     

Patient controlled analgesia (PCA) in paediatric surgery: a prospective study following laparoscopic and open appendicectomy

Patient controlled analgesia (PCA) has not yet gained universal acceptance for the management of postoperative pain in paediatric surgery. In a prospective study we evaluated feasibility and complications of PCA following 90 cases of laparoscopic or open appendicectomy. PCA proved to be a safe and feasible method with few complications (2% of medical complications, no abort of application, 17 technical checks in a total running time of 4125 h). Acceptance by patients was high and children of all age groups worked the system properly. Assessment of application protocols showed, that the consumption of analgesics was significantly reduced following laparoscopic appendicectomy (P < 0.05). PCA is a safe and feasible method for the management of postoperative pain in children and PCA recording provides an excellent insight into the consumptional behaviour of patients, enabling staff to evaluate postoperative pain for various procedures.     

Humoral Immune Responses Against Particulate Bacterial Antigens are Dependent on Marginal Metallophilic Macrophages in the Spleen

Lymphoid organs are populated by different macrophage subpopulations. In the spleen, four subpopulations can be characterized using differences in, for example, morphology, localization, cell markers and repopulation kinetics after liposome-mediated depletion. The involvement of the different macrophage subpopulations in the immune response to particulate antigens was studied in vivo by intravenous injection of clodronate containing liposomes to eliminate the splenic macrophages, followed by immunization with trinitrophenylated Brucella abortus (TNP-BA; thymus-independent (TI)) or TNP- Lactobacillus acidophilus (TNP-LB; thymus-dependent (TD)) at different time intervals. A strong decrease in the number of antibody-secreting cells (ASC) against TNP-LB was measured after elimination of all splenic macrophages. When TNP-LB was injected after repopulation of the red pulp macrophages (completed after 2 weeks), the ASC response was still strongly reduced. Restoration of the capacity to mount an immune response correlated well with the reappearance of the marginal metallophilic macrophages. It is concluded that this particular subset of macrophages is involved in the immune response to these particulate bacterial TD antigens. In contrast, the response against the particulate bacterial TI antigen TNP-BA was not impaired after depletion of splenic macrophages, although apparent changes in IgG isotypes were observed.     

The neuroendocrine challenge paradigm in headache research

The neuroendocrine challenge paradigm provides a "window" on central neurotransmitter function in vivo. This strategy is based on the premise that the sensitivity of certain central receptors can be inferred from the magnitude of the hormonal response to specific pharmacologic probes. For example, the serotonin (5HT) receptor agonist m-chlorophenylpiperazine (m-CPP) stimulates the release of cortisol and prolactin and induces migraine-like headaches. We have previously reported that the headache and cortisol responses to m-CPP are highly correlated, which may implicate a disturbance in central serotonergic neurotransmission in the pathogenesis of migraine. As pharmacologic probes with greater specificity for 5HT receptor subtypes become available, we may be able to elucidate these mechanisms with greater precision. The neuroendocrine challenge methodology is also applicable to the study of other neurotransmitter systems and other headache disorders.     

109Use of EPR Spectroscopy to Measure Tissue Oxygen in an Ischemic Flap Model

Methods to reliably measure tissue oxygenation in situ are currently lacking. We have developed a vertically oriented, dorsal, bipedicle flap model that is easy to perform, reliably reproduces tissue ischemia, eliminates craniocaudal variation, and is amenable to studying therapeutic modalities. The effect of narrowing this flap on tissue oxygenation measured with Licox electrodes has previously been presented. In this study we utilize in situ EPR spectroscopy to demonstrate the oxygen gradient in the flap as a function of flap width and placement of a silicone sheet directly under the flap. The effect of wound healing over a 2 week period is demonstrated. Twenty four, 300 gm male Sprague‐Dawley rats underwent creation of the bipedicle flap according to the following groups: 2.5 cm flap with silicone, 2.0 cm flap without silicone, 2.0 cm flap with silicone. Each group of 6 animals was injected with EMS char at 2 cm intervals along the flap and one injection in the control, non‐ischemic tissue. A 4^th group underwent 2.0 cm flaps with silicone and use of lithium phthalocyanin as the paramagnetic material. Wound measurements and EPR spectroscopy were performed on days 3, 7, 10 and 14. On day 14, after EPR measurements, the animals were sacrificed and their wounds excised. One flap and one control wound were preserved for histologic analysis, the other flap and control wounds were prepared for lactate measurements. EPR spectroscopy demonstrated a gradient of oxygen that was lowest in the center of the flap and greatest at either end. Changes in the oxygen gradient correlated with narrowing and placement of the intervening silicone sheet. This new technology has never been utilized in an animal model of impaired wound healing. Comparison of recently developed paramagnetic materials for optimal tissue oxygen and free radical measurements will be presented.     

Mediastinal lymphadenopathy and pulmonary arterial hypertension in mixed connective tissue disease

A case of mixed connective tissue disease (MCTD) is presented in which mediastinal lymphadenopathy was the most prominent radiological finding detected by plain chest radiographs and computed tomography. Pulmonary arterial hypertension, which is a rare and often fatal complication of MCTD, also developed in this patient.