Intestinal permeability after single dose gluten challenge in coeliac disease.

The changes of intestinal permeability before and after a gluten load were studied. The study group comprised 27 patients with coeliac disease (mean age 12.3 years) and 19 healthy controls matched by sex and age. Intestinal permeability was studied by measuring the urinary excretion of two sugars, lactulose and L-rhamnose, before and six hours after the ingestion of five palatable biscuits made with 50 g of gluten powder. The patients with coeliac disease had been on a gluten free diet during the previous two years. After the gluten load lactulose and L-rhamnose urinary excretion changed significantly in patients, and a significant increase in the lactulose: L-rhamnose ratio was also observed. No significant changes were observed in the controls. In view of the modification of the three biopsies diagnostic protocol made by the European Society for Paediatric Gastroenterology and Nutrition, permeability tests associated with single gluten challenges may be an added contribution to the accuracy of the diagnosis in childhood.     

The mentored clinical casebook project at Harvard Medical School.

An excellent physician must be aware of the countless issues that affect each patient's health. Many medical education programs expose students to a broad spectrum of disparate knowledge and hope they will integrate all the pieces into a coherent whole. The authors describe an explicit approach to integration used at Harvard Medical School since 2003 that aims to enhance students' learning in medical school and throughout their medical careers: the Mentored Clinical Casebook Project (MCCP). The MCCP is constructed on the premise that such integration does not occur suddenly but, rather, is an unending process. A first-year student is assigned to one clinician and follows one patient for one year. The student is expected to spend as much time with the patient as possible, in both clinical and nonclinical settings, seek help from the clinician, and consult other experts and sources to develop a complete picture of the patient's life. The student must produce a casebook that includes, but is not limited to, the patient's history; basic science, clinical, socioeconomic, and cultural issues; and self-reflection. The MCCP is intended to allow students to develop a deeper and more diverse understanding of what comprises a patient's health care life, to discern the patient as a person and the person as a patient. This educational project has been popular with students since its inception, providing them with a personal framework from which to address the needs of future patients and introducing them to how much they will continue to learn from their patients.     

Increased numbers of interleukin-12-producing cells in human tuberculosis.

Numbers of interleukin-12 (IL-12) producing cells were quantitated in the peripheral blood of healthy donors and tuberculosis patients by the ELISPOT assay. We observed that (i) stimulation with mycobacteria increases numbers of IL-12 producers from healthy donors and (ii) tuberculosis patients have larger numbers of IL-12 producers than healthy donors. Our data emphasize the importance of Il-12 in immunity to tuberculosis.     

Living related liver transplantation. Progress or regress?

The impetus for the devolopment of living related liver programmes lies with donor shortage, which relates inversely to the success of generating cadaveric donors. A shrinking or non-existent cadaveric donor pool leads to an increased death rate among potential recipients awaiting transplantation. The living related liver programmes have by and large been successful, though it is accepted that there is potentially a significant risk to the donors. The technique of live donor liver transplantation is clearly here to stay, but the selection of suitable donors is between the family and the unit. Consequently, because of the lack of international guidelines, the programmes are open to abuse. Steps should be taken to establish either mechanisms of control or a worldwide register to combat this potential.     

Measurement of post-operative pain and narcotic administration in infants using a new clinical scoring system

We developed a clinical neurologic and behavioral scoring system composed of 10 items to measure the post-operative pain levels in infants: (1) sleep during preceeding hour, (2) facial expression of pain, (3) quality of cry, (4) spontaneous motor activity, (5) Spontaneous excitability, (6) flexion of fingers and toes, (7) sucking, (8) global evaluation of tone, (9) consolability and (10) sociability. Using this system, a group of infants ranging from one to seven months in age and undergoing minor surgical procedures was studied. The infants were randomly assigned to two groups: Group I received Fentanyl intravenously (3 g/kg) prior to surgery, and Group II received a placebo. The infants then were studied post-operatively in the recovery room at 30, 60, 90 and 120 min intervals. Over the entire post-operative observation period, 54% of the infants in Group I had satisfactory analgesia compared to 18% in Group II. There were no significant differences in Group I and Group II in oxygenation, carbon dioxide elimination, blood pressure, heart rate or temperature.     

Immunocytochemical profile of neurofibrillary tangles in Down's syndrome patients of different ages

Brains were obtained at autopsy from 24 patients with Down's syndrome, ranging in age from 13 to 71 years. Neurofibrillary tangle containing neurones of the hippocampus were stained using a Palmgren silver method and immunocytochemically (PAP) using antisera to paired helical filament protein, human tau protein and ubiquitin, as primary antibody. Counts of cells stained by each method were compared. In patients under 50 years of age, in whom only a limited number of tangle bearing cells were present, the number of profiles visualized with silver, anti-paired helical filament and anti-tau methods were similar. However, in patients over 50 years of age (and in certain of those under 50), in whom numerous tangles were present, the number of cell profiles visualized with silver and anti-paired helical filament methods were still similar though anti-tau detected fewer positive cells. This was because of the increased presence, in such patients, of extracellular tangles which had "lost" anti-tau immunoreactivity. Such data suggest that although tau protein forms a major antigenic determinant of neurofibrillary tangles in Down's syndrome (as it does in Alzheimer's disease) this protein may only decorate the basic paired helical filament protein skeleton, and is removed by macrophagic activity upon neuronal death. In all patients, anti-ubiquitin revealed fewer tangles than any other method. It is possible that ubiquitin may be present only transiently, within tangles perhaps following initial formation and lasting only as long as the normal protein degradation processes remain viable within the diseased neurone.     

The effects of 4-aminopyridine on focal nerve conduction block

In order to test whether 4-aminopyridine (4-AP), a potassium channel blocker, may be of therapeutic value in demyelinating neuropathies, a focal tibial nerve conduction block with demyelination was produced in adult rats by an intraneural microinjection of potassium tellurite. Onset and recovery of the lesion were monitored by evoked compound muscle action potentials (CMAP) activated from the proximal and distal nerve one day before and 1, 4, 7, 14, 21 and 28 days after the injection. Intraperitoneal 4-AP (2 mg/kg) or buffered saline were injected prior to the potassium tellurite and 6 days per week for 28 days. The data show that 4-AP is tolerated, it does not prevent conduction block, and only has a modest effect on increasing its recovery from day 4 to 7 (91 % increase in CMAP ratio compared with control of 35%). Recovery is similar by day 28 in 4-AP treated or untreated animals. These results suggest that 4-AP will have limited use in the therapy of subacute demyelinating neuropathies.     

Comparison of DNA adducts and sister chromatid exchange in lung cancer cases and controls

In a molecular epidemiological study of lung cancer cases (n = 81) and noncancer controls (n = 67), polycyclic aromatic hydrocarbon (PAH)-DNA adducts were evaluated in peripheral blood leukocytes from all subjects and in a smaller number of lung tissue specimens collected prior to or at surgery. Sister chromatid exchanges (SCE) in lymphocytes were also studied in a subset of cases and controls. Questionnaire, medical record, or tumor registry data provided a family history of cancer, as well as information on cigarette smoking, dietary and occupational exposure to PAHs, and other factors related to SCEs. In both cases and controls PAH-DNA adducts in leukocytes measured by an enzyme-linked immunosorbent assay were not significantly related to age, sex, ethnicity, amount of cigarette smoking, passive smoking, dietary charcoal, or caffeine consumption. Nor did family history of cancer or histological type of cancer significantly affect adduct levels. However, when subjects were stratified by smoking status (current, former, and nonsmoker), lung cancer cases who were current smokers had significantly higher levels of covalent adducts than current smoker controls. A seasonal variation was observed in PAH-DNA binding, with a peak in adduct levels during July-October. This peak corresponds to that seen in a prior study of aryl hydrocarbon hydroxylase inducibility by other investigators. The finding of significant levels of PAH-DNA adducts in former smokers and non-smokers supports an earlier observation that this marker is not smoking specific but reflects a pervasive and variable "background" exposure to PAH. These results are consistent with a genetically determined enhancement of PAH-DNA adduct formation in leukocytes of lung cancer cases which is evident in current smokers. The results in lung tissue are limited by the small number of samples. Adduct levels were not significantly increased in lung tissue of smokers compared with nonsmokers. An inverse linear correlation was seen between adduct values in lung tissue and age of the donors. SCEs were significantly related to pack years of smoking. However, there was no difference in the frequency of SCE between cases and controls; nor were SCE and DNA adducts significantly correlated in this small sample.     

Role of mast cells in experimental anti-glomerular basement membrane glomerulonephritis

Recently, divergent reports on the role of mast cells (MC) in different glomerular diseases have brought our attention to their role in an accelerated model of anti-glomerular basement membrane (GBM) glomerulonephritis (GN). Genetically MC-deficient Kit(W)/Kit(W-v) mice, MC-reconstituted Kit(W)/Kit(W-v) mice and Kit+/+ control mice were subjected to anti-GBM GN. Kit(+/+) mice developed moderate proteinuria and glomerular damage following the induction of anti-GBM nephritis. In contrast, proteinuria and glomerular damage were dramatically increased in MC-deficient Kit(W)/Kit(W-v) mice. MC-reconstituted Kit(W)/Kit(W-v) mice showed proteinuria and glomerular damage comparable to Kit+/+ mice. A significant increase in infiltrating T cells and macrophages was detected in MC-deficient Kit(W)/Kit(W-v) mice as compared to Kit+/+ control mice and MC-reconstituted Kit(W)/Kit(W-v) mice. Accordingly, we observed an increase of TGF-beta1 mRNA in kidneys from Kit(W)/Kit(W-v) mice. Interestingly, we did not detect MC in the kidney using either Giemsa staining or RT-real-time PCR, but MC were found in the regional lymph nodes. Finally, mortality of Kit(W)/Kit(W-v) mice was significantly increased after the induction of anti-GBM GN due to uremia. Our report provides the first direct evidence that MC are protective in anti-GBM GN, possibly by modulating the influx of effector T cells and macrophages to inflammatory sites in the kidney.