Nonselective cation channels activated by the stimulation of muscarinic receptors in mammalian gastric smooth muscle.

Muscarinic receptors play key roles in the control of gastrointestinal smooth muscle activity. However, specific physiological functions of each subtype remain to be determined. Single cell RT-PCR experiments showed that all five subtypes of muscarinic receptors were present in circular smooth muscle cells of the guinea-pig gastric antrum. Nonselective cation channels (NSCC) activated by ACh or CCh are coupled to pertussis toxin (PTX)-sensitive Go protein through m4 subtype as well as m2 and m3 subtypes in guinea-pig stomach. CCh-activated currents (I(CCh)), especially the steady-state I-V relationship of I(CCh) showed a chracteristic U-shaped curve; reversal potential of around 0 mV and inward rectification at around +15 mV and a negative slope conductance at negative potential range. Under physiological conditions, the measured single channel conductance of NSCC was approximately 25 pS. The single channel conductance was modulated by external monovalent and divalent cations including Na+, Cs+, Li+, and Ca2+ through changing both the open probability and unitary conductance. Through the NSCC, Ca2+ can move into the cell from extracellular solution as well as Na+. Calculated fractional Ca2+ current of I(CCh) (f(Ca)) was around 1% at the 2 mM [Ca2+]o and at the 4 mM [Ca2+]o, f(Ca) was 2.3%. Quinidine blocked I(CCh) potently in a reversible manner; IC50 was 0.25 microM. There were two kinds of I(CCh) modulations through Ca(2+)-dependent pathways in guinea-pig gastric smooth muscle cells; 1) Facilitation of I(CCh) via Ca2+/CaM-dependent MLCK pathway, 2) Desensitization of I(CCh) via Ca(2+)-dependent PKC pathway. In the mouse stomach, all seven types of TRPC mRNA were detected with RT-PCR. On the basis of electrophysiological, pharmacological, and molecular biological experiments, we reported the mTRPC5 as a candidate for the NSCC activated by muscarinic stimulation in mouse stomach.     

Effects of deoxynivalenol (vomitoxin) on the humoral and cellular immunity of mice

Sublethal doses (0.00, 0.25, 0.50 and 1.00 mg/kg b.w./day) of vomitoxin (deoxynivalenol; DON) were studied for their effects on humoral and cellular immunity and serum proteins of inbred, male Swiss Webster mice in a series of 4 separate experiments. Vomitoxin was added to basal diet (less than the detection limit, i.e., less than 0.05 micrograms of vomitoxin per g of feed) and administered to mice for 5 weeks beginning at 21 days of age. Mice in experiment 2 were fed the basal diet for 40 days in addition to the 5-week treatment with vomitoxin. The 1.00 mg/kg dose of vomitoxin resulted in a statistically significant reduction in the serum levels of alpha 1 and alpha 2-globulins, an increase in total serum albumin, and a reduction in feed consumption and body weight gain compared to the control group. The 0.50 mg/kg dose of vomitoxin resulted in significantly reduced serum levels of alpha 2- and beta-globulins while a significant reduction of feed consumption was evident only during Week 4. Similarly, body weight gain in this group of mice was significantly reduced during Week 2 but increased to normal levels during Week 3 and remained parallel to the control for Week 4 and 5. Both levels (0.50 and 1.00 mg/kg) of vomitoxin resulted in a reduced, dose-related, time-to-death interval following a challenge with L. monocytogenes and increased proliferative capacity of splenic lymphocyte cultures stimulated with the phytohemagglutinin P (PHA-P) mitogen compared to the control group of mice. The 0.25 mg/kg dose of vomitoxin did not have any significant effects on the parameters studied. A reasonable estimation of a 'no effect' level for immunologic effects in mice based on these and previous immunological studies would seem to be between 0.25 and 0.50 mg/kg b.w./day.     

The use of cadaver kidneys for transplantation in young children

The role of cadaver kidney transplantation in the management of end-stage renal disease in young children is controversial. To assess the current risk-benefit ratio of cadaver first and second kidney transplants in recipients under 6 years of age, we compared the outcome of 19 transplants performed between 1984 and 1989 using a quadruple-drug regimen (Minnesota antilymphocyte globulin, azathioprine, prednisone, cyclosporine) with the outcome of 25 transplants performed prior to 1984 without the use of cyclosporine at a single institution. Twenty-five transplants were in children under the age of 3 years. In the last decade patient survival has significantly improved. One-year patient survival improved from 53% before 1979 to 90% since 1979 (P less than 0.05). The use of the quadruple-drug regimen since 1984 was associated with a significant improvement in one-year cadaver graft function from 40% before 1979 to 78% in recipients under 6 years of age, and from 22% to 82% in recipients under 3 years of age (P less than 0.05). With the quadruple-drug regimen, one-year and four-year graft function rates for children under 6 years of age were 83% for first cadaver transplants and 72% for second cadaver transplants, which were essentially the same results as in older children and adults. Children who received kidneys from donors over 4 years of age achieved the best result, with 87% one-year graft function compared with 50% for kidneys from donors under 4 years old. In 15 children with successful transplants, 8 (53%) showed accelerated growth, 5 (33%) had normal-velocity growth, and only 2 children (14%) with suboptimal renal function had poor growth following transplantation. Therefore, we believe that with a quadruple-drug immunosuppressive protocol, cadaver renal transplantation using kidneys from adults or pediatric donors over 4 years old is an acceptable form of treatment in young children with end-stage renal disease for whom there are no suitable living-related donors.     

FM sonography in diffuse liver disease: prospective assessment and blinded analysis

FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease.     

Mycobacterium marinum infection of the hand and wrist. Results of conservative treatment in twenty-four cases

Inadequate débridement, extensive scarring, and breakdown of the wound have been commonly encountered after surgical débridement has been employed as the initial treatment of infection with Mycobacterium marinum involving the deep structures of the hand. Because of our disappointment with the results of this form of treatment, from 1982 to 1986 we treated twenty-four patients who had such an infection with rifampicin and ethambutol after a diagnostic biopsy was done. Surgical treatment was deferred until it was determined that the infection had not been controlled by the chemotherapy. The clinical outcome for these patients could be divided into three patterns: eleven patients (Group I) had a good result with no complications, three patients (Group II) had delayed healing of the wound, and ten patients (Group III) did not have a good response to conservative treatment and required one or more surgical débridements. Complications were sometimes associated with use of the drugs, and loss of visual acuity was a concern in three patients. In twenty-one (87 per cent) of the patients, at follow-up the function of the treated hand was equal to that of the other hand. Persistent pain, a discharging sinus, and previous local injection of steroids were unfavorable prognostic factors. If these factors are present, surgical débridement is advised.     

用于筛选天然产物中脲酶抑制剂的脲酶活性测试方法的建立

抑制幽门螺杆菌产生的脲酶具有治疗胃炎和消化性溃疡的作用。用酚红指示剂和Ｂｅｒｔｈｅｌｏｔ试剂在９６孔培养板上检测重组脲酶活性，其灵敏度指标酚红法每ｍｇ酶蛋白引起的每分钟吸光度变化。△Ａ为６．９，而Ｂｅｒｔｈｅｌｏｔ法每ｍｇ酶蛋白引起的每分钟吸光度比值变化△Ａ为３１３。结果表明用Ｂｅｒｔｈｅｌｏｔ试剂检测重组脲酶活性适宜在９６孔培养板上大规模筛选天然产物中的脲酶抑制剂。